1 /* Target hook definitions.
2 Copyright (C) 2001-2016 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation; either version 3, or (at your option) any
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; see the file COPYING3. If not see
16 <http://www.gnu.org/licenses/>.
18 In other words, you are welcome to use, share and improve this program.
19 You are forbidden to forbid anyone else to use, share and improve
20 what you give them. Help stamp out software-hoarding! */
22 /* See target-hooks-macros.h for details of macros that should be
23 provided by the including file, and how to use them here. */
24 #include "target-hooks-macros.h"
27 #define HOOK_TYPE "Target Hook"
29 HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)
31 /* Functions that output assembler for the target. */
32 #define HOOK_PREFIX "TARGET_ASM_"
33 HOOK_VECTOR (TARGET_ASM_OUT, asm_out)
35 /* Opening and closing parentheses for asm expression grouping. */
38 "These target hooks are C string constants, describing the syntax in the\n\
39 assembler for grouping arithmetic expressions. If not overridden, they\n\
40 default to normal parentheses, which is correct for most assemblers.",
42 DEFHOOKPODX (close_paren, const char *, ")")
44 /* Assembler instructions for creating various kinds of integer object. */
47 "@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP\n\
48 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP\n\
49 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP\n\
50 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP\n\
51 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP\n\
52 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP\n\
53 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP\n\
54 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP\n\
55 These hooks specify assembly directives for creating certain kinds\n\
56 of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
57 byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
58 aligned two-byte object, and so on. Any of the hooks may be\n\
59 @code{NULL}, indicating that no suitable directive is available.\n\
61 The compiler will print these strings at the start of a new line,\n\
62 followed immediately by the object's initial value. In most cases,\n\
63 the string should contain a tab, a pseudo-op, and then another tab.",
64 const char *, "\t.byte\t")
65 DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
66 DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
68 /* The maximum number of bytes to skip when applying
69 LABEL_ALIGN_AFTER_BARRIER. */
71 (label_align_after_barrier_max_skip,
72 "The maximum number of bytes to skip before @var{label} when applying\n\
73 @code{LABEL_ALIGN_AFTER_BARRIER}. This works only if\n\
74 @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
75 int, (rtx_insn *label),
76 default_label_align_after_barrier_max_skip)
78 /* The maximum number of bytes to skip when applying
82 "The maximum number of bytes to skip when applying @code{LOOP_ALIGN} to\n\
83 @var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is\n\
85 int, (rtx_insn *label),
86 default_loop_align_max_skip)
88 /* The maximum number of bytes to skip when applying
91 (label_align_max_skip,
92 "The maximum number of bytes to skip when applying @code{LABEL_ALIGN}\n\
93 to @var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN}\n\
95 int, (rtx_insn *label),
96 default_label_align_max_skip)
98 /* The maximum number of bytes to skip when applying
101 (jump_align_max_skip,
102 "The maximum number of bytes to skip before @var{label} when applying\n\
103 @code{JUMP_ALIGN}. This works only if\n\
104 @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
105 int, (rtx_insn *label),
106 default_jump_align_max_skip)
108 /* Try to output the assembler code for an integer object whose
109 value is given by X. SIZE is the size of the object in bytes and
110 ALIGNED_P indicates whether it is aligned. Return true if
111 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
112 and UNALIGNED_OP are NULL. */
115 "The @code{assemble_integer} function uses this hook to output an\n\
116 integer object. @var{x} is the object's value, @var{size} is its size\n\
117 in bytes and @var{aligned_p} indicates whether it is aligned. The\n\
118 function should return @code{true} if it was able to output the\n\
119 object. If it returns false, @code{assemble_integer} will try to\n\
120 split the object into smaller parts.\n\
122 The default implementation of this hook will use the\n\
123 @code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
124 when the relevant string is @code{NULL}.",
125 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
127 bool, (rtx x, unsigned int size, int aligned_p),
128 default_assemble_integer)
130 /* Notify the backend that we have completed emitting the data for a
134 "Define this hook if the target assembler requires a special marker to\n\
135 terminate an initialized variable declaration.",
139 /* Output code that will globalize a label. */
142 "This target hook is a function to output to the stdio stream\n\
143 @var{stream} some commands that will make the label @var{name} global;\n\
144 that is, available for reference from other files.\n\
146 The default implementation relies on a proper definition of\n\
147 @code{GLOBAL_ASM_OP}.",
148 void, (FILE *stream, const char *name),
149 default_globalize_label)
151 /* Output code that will globalize a declaration. */
153 (globalize_decl_name,
154 "This target hook is a function to output to the stdio stream\n\
155 @var{stream} some commands that will make the name associated with @var{decl}\n\
156 global; that is, available for reference from other files.\n\
158 The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
159 void, (FILE *stream, tree decl), default_globalize_decl_name)
161 /* Output code that will declare an external variable. */
163 (assemble_undefined_decl,
164 "This target hook is a function to output to the stdio stream\n\
165 @var{stream} some commands that will declare the name associated with\n\
166 @var{decl} which is not defined in the current translation unit. Most\n\
167 assemblers do not require anything to be output in this case.",
168 void, (FILE *stream, const char *name, const_tree decl),
169 hook_void_FILEptr_constcharptr_const_tree)
171 /* Output code that will emit a label for unwind info, if this
172 target requires such labels. Second argument is the decl the
173 unwind info is associated with, third is a boolean: true if
174 this is for exception handling, fourth is a boolean: true if
175 this is only a placeholder for an omitted FDE. */
178 "This target hook emits a label at the beginning of each FDE@. It\n\
179 should be defined on targets where FDEs need special labels, and it\n\
180 should write the appropriate label, for the FDE associated with the\n\
181 function declaration @var{decl}, to the stdio stream @var{stream}.\n\
182 The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
183 exception table. The fourth argument, @var{empty}, is a boolean:\n\
184 true if this is a placeholder label for an omitted FDE@.\n\
186 The default is that FDEs are not given nonlocal labels.",
187 void, (FILE *stream, tree decl, int for_eh, int empty),
188 default_emit_unwind_label)
190 /* Output code that will emit a label to divide up the exception table. */
192 (emit_except_table_label,
193 "This target hook emits a label at the beginning of the exception table.\n\
194 It should be defined on targets where it is desirable for the table\n\
195 to be broken up according to function.\n\
197 The default is that no label is emitted.",
198 void, (FILE *stream),
199 default_emit_except_table_label)
201 /* Emit a directive for setting the personality for the function. */
203 (emit_except_personality,
204 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
205 used to emit a directive to install a personality hook into the unwind\
206 info. This hook should not be used if dwarf2 unwind info is used.",
207 void, (rtx personality),
210 /* Emit any directives required to unwind this instruction. */
213 "This target hook emits assembly directives required to unwind the\n\
214 given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
215 returns @code{UI_TARGET}.",
216 void, (FILE *stream, rtx_insn *insn),
220 (unwind_emit_before_insn,
221 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
222 the assembly for @var{insn} has been emitted, false if the hook should\
223 be called afterward.",
226 /* Generate an internal label.
227 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
229 (generate_internal_label,
231 void, (char *buf, const char *prefix, unsigned long labelno),
232 default_generate_internal_label)
234 /* Output an internal label. */
237 "A function to output to the stdio stream @var{stream} a label whose\n\
238 name is made from the string @var{prefix} and the number @var{labelno}.\n\
240 It is absolutely essential that these labels be distinct from the labels\n\
241 used for user-level functions and variables. Otherwise, certain programs\n\
242 will have name conflicts with internal labels.\n\
244 It is desirable to exclude internal labels from the symbol table of the\n\
245 object file. Most assemblers have a naming convention for labels that\n\
246 should be excluded; on many systems, the letter @samp{L} at the\n\
247 beginning of a label has this effect. You should find out what\n\
248 convention your system uses, and follow it.\n\
250 The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
251 void, (FILE *stream, const char *prefix, unsigned long labelno),
252 default_internal_label)
254 /* Output label for the constant. */
256 (declare_constant_name,
257 "A target hook to output to the stdio stream @var{file} any text necessary\n\
258 for declaring the name @var{name} of a constant which is being defined. This\n\
259 target hook is responsible for outputting the label definition (perhaps using\n\
260 @code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
261 and @var{size} is the size of the constant in bytes. The @var{name}\n\
262 will be an internal label.\n\
264 The default version of this target hook, define the @var{name} in the\n\
265 usual manner as a label (by means of @code{assemble_label}).\n\
267 You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
268 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
269 default_asm_declare_constant_name)
271 /* Emit a ttype table reference to a typeinfo object. */
274 "This hook is used to output a reference from a frame unwinding table to\n\
275 the type_info object identified by @var{sym}. It should return @code{true}\n\
276 if the reference was output. Returning @code{false} will cause the\n\
277 reference to be output using the normal Dwarf2 routines.",
281 /* Emit an assembler directive to set visibility for the symbol
282 associated with the tree decl. */
284 (assemble_visibility,
285 "This target hook is a function to output to @var{asm_out_file} some\n\
286 commands that will make the symbol(s) associated with @var{decl} have\n\
287 hidden, protected or internal visibility as specified by @var{visibility}.",
288 void, (tree decl, int visibility),
289 default_assemble_visibility)
291 /* Output the assembler code for entry to a function. */
294 "If defined, a function that outputs the assembler code for entry to a\n\
295 function. The prologue is responsible for setting up the stack frame,\n\
296 initializing the frame pointer register, saving registers that must be\n\
297 saved, and allocating @var{size} additional bytes of storage for the\n\
298 local variables. @var{size} is an integer. @var{file} is a stdio\n\
299 stream to which the assembler code should be output.\n\
301 The label for the beginning of the function need not be output by this\n\
302 macro. That has already been done when the macro is run.\n\
304 @findex regs_ever_live\n\
305 To determine which registers to save, the macro can refer to the array\n\
306 @code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
307 @var{r} is used anywhere within the function. This implies the function\n\
308 prologue should save register @var{r}, provided it is not one of the\n\
309 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
310 @code{regs_ever_live}.)\n\
312 On machines that have ``register windows'', the function entry code does\n\
313 not save on the stack the registers that are in the windows, even if\n\
314 they are supposed to be preserved by function calls; instead it takes\n\
315 appropriate steps to ``push'' the register stack, if any non-call-used\n\
316 registers are used in the function.\n\
318 @findex frame_pointer_needed\n\
319 On machines where functions may or may not have frame-pointers, the\n\
320 function entry code must vary accordingly; it must set up the frame\n\
321 pointer if one is wanted, and not otherwise. To determine whether a\n\
322 frame pointer is in wanted, the macro can refer to the variable\n\
323 @code{frame_pointer_needed}. The variable's value will be 1 at run\n\
324 time in a function that needs a frame pointer. @xref{Elimination}.\n\
326 The function entry code is responsible for allocating any stack space\n\
327 required for the function. This stack space consists of the regions\n\
328 listed below. In most cases, these regions are allocated in the\n\
329 order listed, with the last listed region closest to the top of the\n\
330 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
331 the highest address if it is not defined). You can use a different order\n\
332 for a machine if doing so is more convenient or required for\n\
333 compatibility reasons. Except in cases where required by standard\n\
334 or by a debugger, there is no reason why the stack layout used by GCC\n\
335 need agree with that used by other compilers for a machine.",
336 void, (FILE *file, HOST_WIDE_INT size),
337 default_function_pro_epilogue)
339 /* Output the assembler code for end of prologue. */
341 (function_end_prologue,
342 "If defined, a function that outputs assembler code at the end of a\n\
343 prologue. This should be used when the function prologue is being\n\
344 emitted as RTL, and you have some extra assembler that needs to be\n\
345 emitted. @xref{prologue instruction pattern}.",
349 /* Output the assembler code for start of epilogue. */
351 (function_begin_epilogue,
352 "If defined, a function that outputs assembler code at the start of an\n\
353 epilogue. This should be used when the function epilogue is being\n\
354 emitted as RTL, and you have some extra assembler that needs to be\n\
355 emitted. @xref{epilogue instruction pattern}.",
359 /* Output the assembler code for function exit. */
362 "If defined, a function that outputs the assembler code for exit from a\n\
363 function. The epilogue is responsible for restoring the saved\n\
364 registers and stack pointer to their values when the function was\n\
365 called, and returning control to the caller. This macro takes the\n\
366 same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
367 registers to restore are determined from @code{regs_ever_live} and\n\
368 @code{CALL_USED_REGISTERS} in the same way.\n\
370 On some machines, there is a single instruction that does all the work\n\
371 of returning from the function. On these machines, give that\n\
372 instruction the name @samp{return} and do not define the macro\n\
373 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
375 Do not define a pattern named @samp{return} if you want the\n\
376 @code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
377 switches to control whether return instructions or epilogues are used,\n\
378 define a @samp{return} pattern with a validity condition that tests the\n\
379 target switches appropriately. If the @samp{return} pattern's validity\n\
380 condition is false, epilogues will be used.\n\
382 On machines where functions may or may not have frame-pointers, the\n\
383 function exit code must vary accordingly. Sometimes the code for these\n\
384 two cases is completely different. To determine whether a frame pointer\n\
385 is wanted, the macro can refer to the variable\n\
386 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
387 a function that needs a frame pointer.\n\
389 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
390 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
391 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
392 function. @xref{Leaf Functions}.\n\
394 On some machines, some functions pop their arguments on exit while\n\
395 others leave that for the caller to do. For example, the 68020 when\n\
396 given @option{-mrtd} pops arguments in functions that take a fixed\n\
397 number of arguments.\n\
400 @findex crtl->args.pops_args\n\
401 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
402 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
403 needs to know what was decided. The number of bytes of the current\n\
404 function's arguments that this function should pop is available in\n\
405 @code{crtl->args.pops_args}. @xref{Scalar Return}.",
406 void, (FILE *file, HOST_WIDE_INT size),
407 default_function_pro_epilogue)
409 /* Initialize target-specific sections. */
412 "Define this hook if you need to do something special to set up the\n\
413 @file{varasm.c} sections, or if your target has some special sections\n\
414 of its own that you need to create.\n\
416 GCC calls this hook after processing the command line, but before writing\n\
417 any assembly code, and before calling any of the section-returning hooks\n\
422 /* Tell assembler to change to section NAME with attributes FLAGS.
423 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
424 which this section is associated. */
427 "Output assembly directives to switch to section @var{name}. The section\n\
428 should have attributes as specified by @var{flags}, which is a bit mask\n\
429 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
430 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
431 this section is associated.",
432 void, (const char *name, unsigned int flags, tree decl),
433 default_no_named_section)
435 /* Tell assembler what section attributes to assign this elf section
436 declaration, using their numerical value. */
439 "This hook can be used to encode ELF section flags for which no letter\n\
440 code has been defined in the assembler. It is called by\n\
441 @code{default_asm_named_section} whenever the section flags need to be\n\
442 emitted in the assembler output. If the hook returns true, then the\n\
443 numerical value for ELF section flags should be calculated from\n\
444 @var{flags} and saved in @var{*num}; the value is printed out instead of the\n\
445 normal sequence of letter codes. If the hook is not defined, or if it\n\
446 returns false, then @var{num} is ignored and the traditional letter sequence\n\
448 bool, (unsigned int flags, unsigned int *num),
449 hook_bool_uint_uintp_false)
451 /* Return preferred text (sub)section for function DECL.
452 Main purpose of this function is to separate cold, normal and hot
453 functions. STARTUP is true when function is known to be used only
454 at startup (from static constructors or it is main()).
455 EXIT is true when function is known to be used only at exit
456 (from static destructors).
457 Return NULL if function should go to default text section. */
460 "Return preferred text (sub)section for function @var{decl}.\n\
461 Main purpose of this function is to separate cold, normal and hot\n\
462 functions. @var{startup} is true when function is known to be used only\n\
463 at startup (from static constructors or it is @code{main()}).\n\
464 @var{exit} is true when function is known to be used only at exit\n\
465 (from static destructors).\n\
466 Return NULL if function should go to default text section.",
467 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
468 default_function_section)
470 /* Output the assembler code for function exit. */
472 (function_switched_text_sections,
473 "Used by the target to emit any assembler directives or additional\
474 labels needed when a function is partitioned between different\
475 sections. Output should be written to @var{file}. The function\
476 decl is available as @var{decl} and the new section is `cold' if\
477 @var{new_is_cold} is @code{true}.",
478 void, (FILE *file, tree decl, bool new_is_cold),
479 default_function_switched_text_sections)
481 /* Return a mask describing how relocations should be treated when
482 selecting sections. Bit 1 should be set if global relocations
483 should be placed in a read-write section; bit 0 should be set if
484 local relocations should be placed in a read-write section. */
487 "Return a mask describing how relocations should be treated when\n\
488 selecting sections. Bit 1 should be set if global relocations\n\
489 should be placed in a read-write section; bit 0 should be set if\n\
490 local relocations should be placed in a read-write section.\n\
492 The default version of this function returns 3 when @option{-fpic}\n\
493 is in effect, and 0 otherwise. The hook is typically redefined\n\
494 when the target cannot support (some kinds of) dynamic relocations\n\
495 in read-only sections even in executables.",
497 default_reloc_rw_mask)
499 /* Return a section for EXP. It may be a DECL or a constant. RELOC
500 is nonzero if runtime relocations must be applied; bit 1 will be
501 set if the runtime relocations require non-local name resolution.
502 ALIGN is the required alignment of the data. */
505 "Return the section into which @var{exp} should be placed. You can\n\
506 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
507 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
508 requires link-time relocations. Bit 0 is set when variable contains\n\
509 local relocations only, while bit 1 is set for global relocations.\n\
510 @var{align} is the constant alignment in bits.\n\
512 The default version of this function takes care of putting read-only\n\
513 variables in @code{readonly_data_section}.\n\
515 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
516 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
517 default_select_section)
519 /* Return a section for X. MODE is X's mode and ALIGN is its
520 alignment in bits. */
523 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
524 should be placed. You can assume that @var{x} is some kind of\n\
525 constant in RTL@. The argument @var{mode} is redundant except in the\n\
526 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
529 The default version of this function takes care of putting symbolic\n\
530 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
531 else in @code{readonly_data_section}.",
532 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
533 default_select_rtx_section)
535 /* Select a unique section name for DECL. RELOC is the same as
536 for SELECT_SECTION. */
539 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
540 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
541 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
542 the initial value of @var{exp} requires link-time relocations.\n\
544 The default version of this function appends the symbol name to the\n\
545 ELF section name that would normally be used for the symbol. For\n\
546 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
547 Whatever the actual target object format, this is often good enough.",
548 void, (tree decl, int reloc),
549 default_unique_section)
551 /* Return the readonly data section associated with function DECL. */
553 (function_rodata_section,
554 "Return the readonly data section associated with\n\
555 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
556 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
557 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
558 if function is in @code{.text.name}, and the normal readonly-data section\n\
560 section *, (tree decl),
561 default_function_rodata_section)
563 /* Nonnull if the target wants to override the default ".rodata" prefix
564 for mergeable data sections. */
566 (mergeable_rodata_prefix,
567 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
568 section names for mergeable constant data. Define this macro to override\n\
569 the string if a different section name should be used.",
570 const char *, ".rodata")
572 /* Return the section to be used for transactional memory clone tables. */
574 (tm_clone_table_section,
575 "Return the section that should be used for transactional memory clone\
577 section *, (void), default_clone_table_section)
579 /* Output a constructor for a symbol with a given priority. */
582 "If defined, a function that outputs assembler code to arrange to call\n\
583 the function referenced by @var{symbol} at initialization time.\n\
585 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
586 no arguments and with no return value. If the target supports initialization\n\
587 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
588 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
590 If this macro is not defined by the target, a suitable default will\n\
591 be chosen if (1) the target supports arbitrary section names, (2) the\n\
592 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
594 void, (rtx symbol, int priority), NULL)
596 /* Output a destructor for a symbol with a given priority. */
599 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
600 functions rather than initialization functions.",
601 void, (rtx symbol, int priority), NULL)
603 /* Output the assembler code for a thunk function. THUNK_DECL is the
604 declaration for the thunk function itself, FUNCTION is the decl for
605 the target function. DELTA is an immediate constant offset to be
606 added to THIS. If VCALL_OFFSET is nonzero, the word at
607 *(*this + vcall_offset) should be added to THIS. */
610 "A function that outputs the assembler code for a thunk\n\
611 function, used to implement C++ virtual function calls with multiple\n\
612 inheritance. The thunk acts as a wrapper around a virtual function,\n\
613 adjusting the implicit object parameter before handing control off to\n\
614 the real function.\n\
616 First, emit code to add the integer @var{delta} to the location that\n\
617 contains the incoming first argument. Assume that this argument\n\
618 contains a pointer, and is the one used to pass the @code{this} pointer\n\
619 in C++. This is the incoming argument @emph{before} the function prologue,\n\
620 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
621 all other incoming arguments.\n\
623 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
624 made after adding @code{delta}. In particular, if @var{p} is the\n\
625 adjusted pointer, the following adjustment should be made:\n\
628 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
631 After the additions, emit code to jump to @var{function}, which is a\n\
632 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
633 not touch the return address. Hence returning from @var{FUNCTION} will\n\
634 return to whoever called the current @samp{thunk}.\n\
636 The effect must be as if @var{function} had been called directly with\n\
637 the adjusted first argument. This macro is responsible for emitting all\n\
638 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
639 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
641 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
642 have already been extracted from it.) It might possibly be useful on\n\
643 some targets, but probably not.\n\
645 If you do not define this macro, the target-independent code in the C++\n\
646 front end will generate a less efficient heavyweight thunk that calls\n\
647 @var{function} instead of jumping to it. The generic approach does\n\
648 not support varargs.",
649 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
650 HOST_WIDE_INT vcall_offset, tree function),
653 /* Determine whether output_mi_thunk would succeed. */
654 /* ??? Ideally, this hook would not exist, and success or failure
655 would be returned from output_mi_thunk directly. But there's
656 too much undo-able setup involved in invoking output_mi_thunk.
657 Could be fixed by making output_mi_thunk emit rtl instead of
658 text to the output file. */
660 (can_output_mi_thunk,
661 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
662 to output the assembler code for the thunk function specified by the\n\
663 arguments it is passed, and false otherwise. In the latter case, the\n\
664 generic approach will be used by the C++ front end, with the limitations\n\
665 previously exposed.",
666 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
667 HOST_WIDE_INT vcall_offset, const_tree function),
668 hook_bool_const_tree_hwi_hwi_const_tree_false)
670 /* Output any boilerplate text needed at the beginning of a
674 "Output to @code{asm_out_file} any text which the assembler expects to\n\
675 find at the beginning of a file. The default behavior is controlled\n\
676 by two flags, documented below. Unless your target's assembler is\n\
677 quite unusual, if you override the default, you should call\n\
678 @code{default_file_start} at some point in your target hook. This\n\
679 lets other target files rely on these variables.",
683 /* Output any boilerplate text needed at the end of a translation unit. */
686 "Output to @code{asm_out_file} any text which the assembler expects\n\
687 to find at the end of a file. The default is to output nothing.",
691 /* Output any boilerplate text needed at the beginning of an
692 LTO output stream. */
695 "Output to @code{asm_out_file} any text which the assembler expects\n\
696 to find at the start of an LTO section. The default is to output\n\
701 /* Output any boilerplate text needed at the end of an
702 LTO output stream. */
705 "Output to @code{asm_out_file} any text which the assembler expects\n\
706 to find at the end of an LTO section. The default is to output\n\
711 /* Output any boilerplace text needed at the end of a
712 translation unit before debug and unwind info is emitted. */
715 "Output to @code{asm_out_file} any text which is needed before emitting\n\
716 unwind info and debug info at the end of a file. Some targets emit\n\
717 here PIC setup thunks that cannot be emitted at the end of file,\n\
718 because they couldn't have unwind info then. The default is to output\n\
723 /* Output an assembler pseudo-op to declare a library function name
727 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
728 pseudo-op to declare a library function name external. The name of the\n\
729 library function is given by @var{symref}, which is a @code{symbol_ref}.",
731 default_external_libcall)
733 /* Output an assembler directive to mark decl live. This instructs
734 linker to not dead code strip this symbol. */
736 (mark_decl_preserved,
737 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
738 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
739 .no_dead_code_strip directive.",
740 void, (const char *symbol),
741 hook_void_constcharptr)
743 /* Output a record of the command line switches that have been passed. */
745 (record_gcc_switches,
746 "Provides the target with the ability to record the gcc command line\n\
747 switches that have been passed to the compiler, and options that are\n\
748 enabled. The @var{type} argument specifies what is being recorded.\n\
749 It can take the following values:\n\
752 @item SWITCH_TYPE_PASSED\n\
753 @var{text} is a command line switch that has been set by the user.\n\
755 @item SWITCH_TYPE_ENABLED\n\
756 @var{text} is an option which has been enabled. This might be as a\n\
757 direct result of a command line switch, or because it is enabled by\n\
758 default or because it has been enabled as a side effect of a different\n\
759 command line switch. For example, the @option{-O2} switch enables\n\
760 various different individual optimization passes.\n\
762 @item SWITCH_TYPE_DESCRIPTIVE\n\
763 @var{text} is either NULL or some descriptive text which should be\n\
764 ignored. If @var{text} is NULL then it is being used to warn the\n\
765 target hook that either recording is starting or ending. The first\n\
766 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
767 warning is for start up and the second time the warning is for\n\
768 wind down. This feature is to allow the target hook to make any\n\
769 necessary preparations before it starts to record switches and to\n\
770 perform any necessary tidying up after it has finished recording\n\
773 @item SWITCH_TYPE_LINE_START\n\
774 This option can be ignored by this target hook.\n\
776 @item SWITCH_TYPE_LINE_END\n\
777 This option can be ignored by this target hook.\n\
780 The hook's return value must be zero. Other return values may be\n\
781 supported in the future.\n\
783 By default this hook is set to NULL, but an example implementation is\n\
784 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
785 it records the switches as ASCII text inside a new, string mergeable\n\
786 section in the assembler output file. The name of the new section is\n\
787 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
789 int, (print_switch_type type, const char *text),
792 /* The name of the section that the example ELF implementation of
793 record_gcc_switches will use to store the information. Target
794 specific versions of record_gcc_switches may or may not use
797 (record_gcc_switches_section,
798 "This is the name of the section that will be created by the example\n\
799 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
801 const char *, ".GCC.command.line")
803 /* Output the definition of a section anchor. */
806 "Write the assembly code to define section anchor @var{x}, which is a\n\
807 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
808 The hook is called with the assembly output position set to the beginning\n\
809 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
811 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
812 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
813 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
814 is @code{NULL}, which disables the use of section anchors altogether.",
816 default_asm_output_anchor)
820 "Output a string based on @var{name}, suitable for the @samp{#ident} \
821 directive, or the equivalent directive or pragma in non-C-family languages. \
822 If this hook is not defined, nothing is output for the @samp{#ident} \
824 void, (const char *name),
825 hook_void_constcharptr)
827 /* Output a DTP-relative reference to a TLS symbol. */
829 (output_dwarf_dtprel,
830 "If defined, this target hook is a function which outputs a DTP-relative\n\
831 reference to the given TLS symbol of the specified size.",
832 void, (FILE *file, int size, rtx x),
835 /* Some target machines need to postscan each insn after it is output. */
837 (final_postscan_insn,
838 "If defined, this target hook is a function which is executed just after the\n\
839 output of assembler code for @var{insn}, to change the mode of the assembler\n\
842 Here the argument @var{opvec} is the vector containing the operands\n\
843 extracted from @var{insn}, and @var{noperands} is the number of\n\
844 elements of the vector which contain meaningful data for this insn.\n\
845 The contents of this vector are what was used to convert the insn\n\
846 template into assembler code, so you can change the assembler mode\n\
847 by checking the contents of the vector.",
848 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
851 /* Emit the trampoline template. This hook may be NULL. */
853 (trampoline_template,
854 "This hook is called by @code{assemble_trampoline_template} to output,\n\
855 on the stream @var{f}, assembler code for a block of data that contains\n\
856 the constant parts of a trampoline. This code should not include a\n\
857 label---the label is taken care of automatically.\n\
859 If you do not define this hook, it means no template is needed\n\
860 for the target. Do not define this hook on systems where the block move\n\
861 code to copy the trampoline into place would be larger than the code\n\
862 to generate it on the spot.",
867 (output_source_filename,
868 "Output COFF information or DWARF debugging information which indicates\
869 that filename @var{name} is the current source file to the stdio\
870 stream @var{file}.\n\
872 This target hook need not be defined if the standard form of output\
873 for the file format in use is appropriate.",
874 void ,(FILE *file, const char *name),
875 default_asm_output_source_filename)
878 (output_addr_const_extra,
879 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
880 can't deal with, and output assembly code to @var{file} corresponding to\n\
881 the pattern @var{x}. This may be used to allow machine-dependent\n\
882 @code{UNSPEC}s to appear within constants.\n\
884 If target hook fails to recognize a pattern, it must return @code{false},\n\
885 so that a standard error message is printed. If it prints an error message\n\
886 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
887 return @code{true}.",
888 bool, (FILE *file, rtx x),
889 hook_bool_FILEptr_rtx_false)
891 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
892 even though that is not reflected in the macro name to override their
895 #define HOOK_PREFIX "TARGET_"
897 /* Emit a machine-specific insn operand. */
898 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
899 not this hook, and uses a different name for the argument FILE. */
903 void, (FILE *file, rtx x, int code),
904 default_print_operand)
906 /* Emit a machine-specific memory address. */
907 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
908 not this hook, and uses different argument names. */
910 (print_operand_address,
912 void, (FILE *file, machine_mode mode, rtx addr),
913 default_print_operand_address)
915 /* Determine whether CODE is a valid punctuation character for the
916 `print_operand' hook. */
917 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
920 (print_operand_punct_valid_p,
922 bool ,(unsigned char code),
923 default_print_operand_punct_valid_p)
925 /* Given a symbol name, perform same mangling as assemble_name and
926 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
928 (mangle_assembler_name,
929 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
930 @code{assemble_name}, but in memory rather than to a file stream, returning\
931 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
932 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
933 then prepends the @code{USER_LABEL_PREFIX}, if any.",
934 tree, (const char *name),
935 default_mangle_assembler_name)
937 HOOK_VECTOR_END (asm_out)
939 /* Functions relating to instruction scheduling. All of these
940 default to null pointers, which haifa-sched.c looks for and handles. */
942 #define HOOK_PREFIX "TARGET_SCHED_"
943 HOOK_VECTOR (TARGET_SCHED, sched)
945 /* Given the current cost, COST, of an insn, INSN, calculate and
946 return a new cost based on its relationship to DEP_INSN through
947 the dependence LINK. The default is to make no adjustment. */
950 "This function corrects the value of @var{cost} based on the\n\
951 relationship between @var{insn} and @var{dep_insn} through a\n\
952 dependence of type dep_type, and strength @var{dw}. It should return the new\n\
953 value. The default is to make no adjustment to @var{cost}. This can be\n\
954 used for example to specify to the scheduler using the traditional pipeline\n\
955 description that an output- or anti-dependence does not incur the same cost\n\
956 as a data-dependence. If the scheduler using the automaton based pipeline\n\
957 description, the cost of anti-dependence is zero and the cost of\n\
958 output-dependence is maximum of one and the difference of latency\n\
959 times of the first and the second insns. If these values are not\n\
960 acceptable, you could use the hook to modify them too. See also\n\
961 @pxref{Processor pipeline description}.",
962 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
966 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
969 "This hook adjusts the integer scheduling priority @var{priority} of\n\
970 @var{insn}. It should return the new priority. Increase the priority to\n\
971 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
972 later. Do not define this hook if you do not need to adjust the\n\
973 scheduling priorities of insns.",
974 int, (rtx_insn *insn, int priority), NULL)
976 /* Function which returns the maximum number of insns that can be
977 scheduled in the same machine cycle. This must be constant
978 over an entire compilation. The default is 1. */
981 "This hook returns the maximum number of instructions that can ever\n\
982 issue at the same time on the target machine. The default is one.\n\
983 Although the insn scheduler can define itself the possibility of issue\n\
984 an insn on the same cycle, the value can serve as an additional\n\
985 constraint to issue insns on the same simulated processor cycle (see\n\
986 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
987 This value must be constant over the entire compilation. If you need\n\
988 it to vary depending on what the instructions are, you must use\n\
989 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
992 /* Calculate how much this insn affects how many more insns we
993 can emit this cycle. Default is they all cost the same. */
996 "This hook is executed by the scheduler after it has scheduled an insn\n\
997 from the ready list. It should return the number of insns which can\n\
998 still be issued in the current cycle. The default is\n\
999 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
1000 @code{USE}, which normally are not counted against the issue rate.\n\
1001 You should define this hook if some insns take more machine resources\n\
1002 than others, so that fewer insns can follow them in the same cycle.\n\
1003 @var{file} is either a null pointer, or a stdio stream to write any\n\
1004 debug output to. @var{verbose} is the verbose level provided by\n\
1005 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
1007 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
1009 /* Initialize machine-dependent scheduling code. */
1012 "This hook is executed by the scheduler at the beginning of each block of\n\
1013 instructions that are to be scheduled. @var{file} is either a null\n\
1014 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
1015 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1016 @var{max_ready} is the maximum number of insns in the current scheduling\n\
1017 region that can be live at the same time. This can be used to allocate\n\
1018 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1019 void, (FILE *file, int verbose, int max_ready), NULL)
1021 /* Finalize machine-dependent scheduling code. */
1024 "This hook is executed by the scheduler at the end of each block of\n\
1025 instructions that are to be scheduled. It can be used to perform\n\
1026 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1027 is either a null pointer, or a stdio stream to write any debug output\n\
1028 to. @var{verbose} is the verbose level provided by\n\
1029 @option{-fsched-verbose-@var{n}}.",
1030 void, (FILE *file, int verbose), NULL)
1032 /* Initialize machine-dependent function wide scheduling code. */
1035 "This hook is executed by the scheduler after function level initializations.\n\
1036 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1037 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1038 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1039 void, (FILE *file, int verbose, int old_max_uid), NULL)
1041 /* Finalize machine-dependent function wide scheduling code. */
1044 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1045 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1046 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1047 void, (FILE *file, int verbose), NULL)
1049 /* Reorder insns in a machine-dependent fashion, in two different
1050 places. Default does nothing. */
1053 "This hook is executed by the scheduler after it has scheduled the ready\n\
1054 list, to allow the machine description to reorder it (for example to\n\
1055 combine two small instructions together on @samp{VLIW} machines).\n\
1056 @var{file} is either a null pointer, or a stdio stream to write any\n\
1057 debug output to. @var{verbose} is the verbose level provided by\n\
1058 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1059 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1060 a pointer to the number of elements in the ready list. The scheduler\n\
1061 reads the ready list in reverse order, starting with\n\
1062 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1063 is the timer tick of the scheduler. You may modify the ready list and\n\
1064 the number of ready insns. The return value is the number of insns that\n\
1065 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1066 @samp{TARGET_SCHED_REORDER2}.",
1067 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1071 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1072 function is called whenever the scheduler starts a new cycle. This one\n\
1073 is called once per iteration over a cycle, immediately after\n\
1074 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1075 return the number of insns to be scheduled in the same cycle. Defining\n\
1076 this hook can be useful if there are frequent situations where\n\
1077 scheduling one insn causes other insns to become ready in the same\n\
1078 cycle. These other insns can then be taken into account properly.",
1079 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1083 "This hook is used to check whether target platform supports macro fusion.",
1087 (macro_fusion_pair_p,
1088 "This hook is used to check whether two insns should be macro fused for\n\
1089 a target microarchitecture. If this hook returns true for the given insn pair\n\
1090 (@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1091 group, and they will not be scheduled apart. The two insns will be either\n\
1092 two SET insns or a compare and a conditional jump and this hook should\n\
1093 validate any dependencies needed to fuse the two insns together.",
1094 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1096 /* The following member value is a pointer to a function called
1097 after evaluation forward dependencies of insns in chain given
1098 by two parameter values (head and tail correspondingly). */
1100 (dependencies_evaluation_hook,
1101 "This hook is called after evaluation forward dependencies of insns in\n\
1102 chain given by two parameter values (@var{head} and @var{tail}\n\
1103 correspondingly) but before insns scheduling of the insn chain. For\n\
1104 example, it can be used for better insn classification if it requires\n\
1105 analysis of dependencies. This hook can use backward and forward\n\
1106 dependencies of the insn scheduler because they are already\n\
1108 void, (rtx_insn *head, rtx_insn *tail), NULL)
1110 /* The values of the following four members are pointers to functions
1111 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1112 dfa_post_cycle_insn give functions returning insns which are used to
1113 change the pipeline hazard recognizer state when the new simulated
1114 processor cycle correspondingly starts and finishes. The function
1115 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1116 used to initialize the corresponding insns. The default values of
1117 the members result in not changing the automaton state when the
1118 new simulated processor cycle correspondingly starts and finishes. */
1121 (init_dfa_pre_cycle_insn,
1122 "The hook can be used to initialize data used by the previous hook.",
1126 (dfa_pre_cycle_insn,
1127 "The hook returns an RTL insn. The automaton state used in the\n\
1128 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1129 when the new simulated processor cycle starts. Usage of the hook may\n\
1130 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1131 processors. If the hook is defined, it is used only for the automaton\n\
1132 based pipeline description. The default is not to change the state\n\
1133 when the new simulated processor cycle starts.",
1137 (init_dfa_post_cycle_insn,
1138 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1139 used to initialize data used by the previous hook.",
1143 (dfa_post_cycle_insn,
1144 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1145 to changed the state as if the insn were scheduled when the new\n\
1146 simulated processor cycle finishes.",
1147 rtx_insn *, (void), NULL)
1149 /* The values of the following two members are pointers to
1150 functions used to simplify the automaton descriptions.
1151 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1152 immediately before and after cycle is advanced. */
1155 (dfa_pre_advance_cycle,
1156 "The hook to notify target that the current simulated cycle is about to finish.\n\
1157 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1158 to change the state in more complicated situations - e.g., when advancing\n\
1159 state on a single insn is not enough.",
1163 (dfa_post_advance_cycle,
1164 "The hook to notify target that new simulated cycle has just started.\n\
1165 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1166 to change the state in more complicated situations - e.g., when advancing\n\
1167 state on a single insn is not enough.",
1170 /* The following member value is a pointer to a function returning value
1171 which defines how many insns in queue `ready' will we try for
1172 multi-pass scheduling. If the member value is nonzero and the
1173 function returns positive value, the DFA based scheduler will make
1174 multi-pass scheduling for the first cycle. In other words, we will
1175 try to choose ready insn which permits to start maximum number of
1176 insns on the same cycle. */
1178 (first_cycle_multipass_dfa_lookahead,
1179 "This hook controls better choosing an insn from the ready insn queue\n\
1180 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1181 chooses the first insn from the queue. If the hook returns a positive\n\
1182 value, an additional scheduler code tries all permutations of\n\
1183 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1184 subsequent ready insns to choose an insn whose issue will result in\n\
1185 maximal number of issued insns on the same cycle. For the\n\
1186 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1187 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1188 rules of @acronym{VLIW} packing are described in the automaton.\n\
1190 This code also could be used for superscalar @acronym{RISC}\n\
1191 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1192 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1193 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1194 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1195 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1196 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1197 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1198 the processor could issue all 3 insns per cycle.\n\
1200 Actually this code demonstrates advantages of the automaton based\n\
1201 pipeline hazard recognizer. We try quickly and easy many insn\n\
1202 schedules to choose the best one.\n\
1204 The default is no multipass scheduling.",
1207 /* The following member value is pointer to a function controlling
1208 what insns from the ready insn queue will be considered for the
1209 multipass insn scheduling. If the hook returns zero for insn
1210 passed as the parameter, the insn will be not chosen to be issued. */
1212 (first_cycle_multipass_dfa_lookahead_guard,
1214 This hook controls what insns from the ready insn queue will be\n\
1215 considered for the multipass insn scheduling. If the hook returns\n\
1216 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1217 Positive return values will remove @var{insn} from consideration on\n\
1218 the current round of multipass scheduling.\n\
1219 Negative return values will remove @var{insn} from consideration for given\n\
1220 number of cycles.\n\
1221 Backends should be careful about returning non-zero for highest priority\n\
1222 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1223 to allow backends make correct judgements.\n\
1225 The default is that any ready insns can be chosen to be issued.",
1226 int, (rtx_insn *insn, int ready_index), NULL)
1228 /* This hook prepares the target for a new round of multipass
1230 DATA is a pointer to target-specific data used for multipass scheduling.
1231 READY_TRY and N_READY represent the current state of search in the
1232 optimization space. The target can filter out instructions that
1233 should not be tried during current round by setting corresponding
1234 elements in READY_TRY to non-zero.
1235 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1236 scheduling on current cycle. */
1238 (first_cycle_multipass_begin,
1239 "This hook prepares the target backend for a new round of multipass\n\
1241 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1244 /* This hook is called when multipass scheduling evaluates instruction INSN.
1245 DATA is a pointer to target-specific data that can be used to record effects
1246 of INSN on CPU that are not described in DFA.
1247 READY_TRY and N_READY represent the current state of search in the
1248 optimization space. The target can filter out instructions that
1249 should not be tried after issuing INSN by setting corresponding
1250 elements in READY_TRY to non-zero.
1251 INSN is the instruction being evaluated.
1252 PREV_DATA is a pointer to target-specific data corresponding
1253 to a state before issuing INSN. */
1255 (first_cycle_multipass_issue,
1256 "This hook is called when multipass scheduling evaluates instruction INSN.",
1257 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1258 const void *prev_data), NULL)
1260 /* This hook is called when multipass scheduling backtracks from evaluation of
1261 instruction corresponding to DATA.
1262 DATA is a pointer to target-specific data that stores the effects
1263 of instruction from which the algorithm backtracks on CPU that are not
1265 READY_TRY and N_READY represent the current state of search in the
1266 optimization space. The target can filter out instructions that
1267 should not be tried after issuing INSN by setting corresponding
1268 elements in READY_TRY to non-zero. */
1270 (first_cycle_multipass_backtrack,
1271 "This is called when multipass scheduling backtracks from evaluation of\n\
1273 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1275 /* This hook notifies the target about the result of the concluded current
1276 round of multipass scheduling.
1278 If DATA is non-NULL it points to target-specific data used for multipass
1279 scheduling which corresponds to instruction at the start of the chain of
1280 the winning solution. DATA is NULL when multipass scheduling cannot find
1281 a good enough solution on current cycle and decides to retry later,
1282 usually after advancing the cycle count. */
1284 (first_cycle_multipass_end,
1285 "This hook notifies the target about the result of the concluded current\n\
1286 round of multipass scheduling.",
1287 void, (const void *data), NULL)
1289 /* This hook is called to initialize target-specific data for multipass
1290 scheduling after it has been allocated.
1291 DATA is a pointer to target-specific data that stores the effects
1292 of instruction from which the algorithm backtracks on CPU that are not
1293 described in DFA. */
1295 (first_cycle_multipass_init,
1296 "This hook initializes target-specific data used in multipass scheduling.",
1297 void, (void *data), NULL)
1299 /* This hook is called to finalize target-specific data for multipass
1300 scheduling before it is deallocated.
1301 DATA is a pointer to target-specific data that stores the effects
1302 of instruction from which the algorithm backtracks on CPU that are not
1303 described in DFA. */
1305 (first_cycle_multipass_fini,
1306 "This hook finalizes target-specific data used in multipass scheduling.",
1307 void, (void *data), NULL)
1309 /* The following member value is pointer to a function called by
1310 the insn scheduler before issuing insn passed as the third
1311 parameter on given cycle. If the hook returns nonzero, the
1312 insn is not issued on given processors cycle. Instead of that,
1313 the processor cycle is advanced. If the value passed through
1314 the last parameter is zero, the insn ready queue is not sorted
1315 on the new cycle start as usually. The first parameter passes
1316 file for debugging output. The second one passes the scheduler
1317 verbose level of the debugging output. The forth and the fifth
1318 parameter values are correspondingly processor cycle on which
1319 the previous insn has been issued and the current processor cycle. */
1322 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1323 on cycle @var{clock}. If the hook returns nonzero,\n\
1324 @var{insn} is not issued on this processor cycle. Instead,\n\
1325 the processor cycle is advanced. If *@var{sort_p}\n\
1326 is zero, the insn ready queue is not sorted on the new cycle\n\
1327 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1328 verbosity level to use for debugging output.\n\
1329 @var{last_clock} and @var{clock} are, respectively, the\n\
1330 processor cycle on which the previous insn has been issued,\n\
1331 and the current processor cycle.",
1332 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1333 int clock, int *sort_p),
1336 /* The following member value is a pointer to a function called by the
1337 insn scheduler. It should return true if there exists a dependence
1338 which is considered costly by the target, between the insn
1339 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1340 the dep that represents the dependence between the two insns. The
1341 second argument is the cost of the dependence as estimated by
1342 the scheduler. The last argument is the distance in cycles
1343 between the already scheduled insn (first parameter) and the
1344 second insn (second parameter). */
1346 (is_costly_dependence,
1347 "This hook is used to define which dependences are considered costly by\n\
1348 the target, so costly that it is not advisable to schedule the insns that\n\
1349 are involved in the dependence too close to one another. The parameters\n\
1350 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1351 being evaluated. The second parameter @var{cost} is the cost of the\n\
1352 dependence as estimated by the scheduler, and the third\n\
1353 parameter @var{distance} is the distance in cycles between the two insns.\n\
1354 The hook returns @code{true} if considering the distance between the two\n\
1355 insns the dependence between them is considered costly by the target,\n\
1356 and @code{false} otherwise.\n\
1358 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1359 where (a) it's practically hopeless to predict the actual data/resource\n\
1360 delays, however: (b) there's a better chance to predict the actual grouping\n\
1361 that will be formed, and (c) correctly emulating the grouping can be very\n\
1362 important. In such targets one may want to allow issuing dependent insns\n\
1363 closer to one another---i.e., closer than the dependence distance; however,\n\
1364 not in cases of ``costly dependences'', which this hooks allows to define.",
1365 bool, (struct _dep *_dep, int cost, int distance), NULL)
1367 /* The following member value is a pointer to a function called
1368 by the insn scheduler. This hook is called to notify the backend
1369 that new instructions were emitted. */
1372 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1373 the instruction stream. The hook notifies a target backend to extend its\n\
1374 per instruction data structures.",
1377 /* Next 5 functions are for multi-point scheduling. */
1379 /* Allocate memory for scheduler context. */
1381 (alloc_sched_context,
1382 "Return a pointer to a store large enough to hold target scheduling context.",
1383 void *, (void), NULL)
1385 /* Fills the context from the local machine scheduler context. */
1387 (init_sched_context,
1388 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1389 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1390 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1391 void, (void *tc, bool clean_p), NULL)
1393 /* Sets local machine scheduler context to a saved value. */
1396 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1397 void, (void *tc), NULL)
1399 /* Clears a scheduler context so it becomes like after init. */
1401 (clear_sched_context,
1402 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1403 void, (void *tc), NULL)
1405 /* Frees the scheduler context. */
1407 (free_sched_context,
1408 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1409 void, (void *tc), NULL)
1411 /* The following member value is a pointer to a function called
1412 by the insn scheduler.
1413 The first parameter is an instruction, the second parameter is the type
1414 of the requested speculation, and the third parameter is a pointer to the
1415 speculative pattern of the corresponding type (set if return value == 1).
1417 -1, if there is no pattern, that will satisfy the requested speculation type,
1418 0, if current pattern satisfies the requested speculation type,
1419 1, if pattern of the instruction should be changed to the newly
1423 "This hook is called by the insn scheduler when @var{insn} has only\n\
1424 speculative dependencies and therefore can be scheduled speculatively.\n\
1425 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1426 version and, in case of successful check, to generate that speculative\n\
1427 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1428 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1429 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1430 the generated speculative pattern.",
1431 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1433 /* The following member value is a pointer to a function called
1434 by the insn scheduler. It should return true if the check instruction
1435 passed as the parameter needs a recovery block. */
1438 "This hook is called by the insn scheduler during generation of recovery code\n\
1439 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1440 instruction should branch to recovery code, or @code{false} otherwise.",
1441 bool, (unsigned int dep_status), NULL)
1443 /* The following member value is a pointer to a function called
1444 by the insn scheduler. It should return a pattern for the check
1446 The first parameter is a speculative instruction, the second parameter
1447 is the label of the corresponding recovery block (or null, if it is a
1448 simple check). The third parameter is the kind of speculation that
1449 is being performed. */
1452 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1453 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1454 speculative instruction for which the check should be generated.\n\
1455 @var{label} is either a label of a basic block, where recovery code should\n\
1456 be emitted, or a null pointer, when requested check doesn't branch to\n\
1457 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1458 a pattern for a branchy check corresponding to a simple check denoted by\n\
1459 @var{insn} should be generated. In this case @var{label} can't be null.",
1460 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1462 /* The following member value is a pointer to a function that provides
1463 information about the speculation capabilities of the target.
1464 The parameter is a pointer to spec_info variable. */
1467 "This hook is used by the insn scheduler to find out what features should be\n\
1469 The structure *@var{spec_info} should be filled in by the target.\n\
1470 The structure describes speculation types that can be used in the scheduler.",
1471 void, (struct spec_info_def *spec_info), NULL)
1475 "Return speculation types of instruction @var{insn}.",
1476 unsigned int, (rtx_insn *insn), NULL)
1479 (get_insn_checked_ds,
1480 "Return speculation types that are checked for instruction @var{insn}",
1481 unsigned int, (rtx_insn *insn), NULL)
1485 "Return bool if rtx scanning should just skip current layer and\
1486 advance to the inner rtxes.",
1487 bool, (const_rtx x), NULL)
1489 /* The following member value is a pointer to a function that provides
1490 information about the target resource-based lower bound which is
1491 used by the swing modulo scheduler. The parameter is a pointer
1495 "This hook is called by the swing modulo scheduler to calculate a\n\
1496 resource-based lower bound which is based on the resources available in\n\
1497 the machine and the resources required by each instruction. The target\n\
1498 backend can use @var{g} to calculate such bound. A very simple lower\n\
1499 bound will be used in case this hook is not implemented: the total number\n\
1500 of instructions divided by the issue rate.",
1501 int, (struct ddg *g), NULL)
1503 /* The following member value is a function that initializes dispatch
1504 schedling and adds instructions to dispatch window according to its
1508 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1509 in its second parameter.",
1510 void, (rtx_insn *insn, int x),
1511 hook_void_rtx_insn_int)
1513 /* The following member value is a a function that returns true is
1514 dispatch schedling is supported in hardware and condition passed
1515 as the second parameter is true. */
1518 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1519 is supported in hardware and the condition specified in the parameter is true.",
1520 bool, (rtx_insn *insn, int x),
1521 hook_bool_rtx_insn_int_false)
1525 "True if the processor has an exposed pipeline, which means that not just\n\
1526 the order of instructions is important for correctness when scheduling, but\n\
1527 also the latencies of operations.",
1530 /* The following member value is a function that returns number
1531 of operations reassociator should try to put in parallel for
1532 statements of the given type. By default 1 is used. */
1534 (reassociation_width,
1535 "This hook is called by tree reassociator to determine a level of\n\
1536 parallelism required in output calculations chain.",
1537 int, (unsigned int opc, machine_mode mode),
1538 hook_int_uint_mode_1)
1540 /* The following member value is a function that returns priority for
1541 fusion of each instruction via pointer parameters. */
1544 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1545 priorities for each instruction passed in by parameter. The priorities\n\
1546 are returned via pointer parameters.\n\
1548 @var{insn} is the instruction whose priorities need to be calculated.\n\
1549 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1550 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1551 fusion priority should be calculated and returned.\n\
1552 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1553 should be calculated and returned.\n\
1555 Same @var{fusion_pri} should be returned for instructions which should\n\
1556 be scheduled together. Different @var{pri} should be returned for\n\
1557 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1558 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1559 scheduled according to the two priorities. All priorities calculated\n\
1560 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1561 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1562 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1565 Given below example:\n\
1574 ldr r16, [r2, 12]\n\
1576 @end smallexample\n\
1578 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1579 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1580 loads are actually next to each other in instruction flow. That's where\n\
1581 this scheduling fusion pass works. This hook calculates priority for each\n\
1582 instruction based on its fustion type, like:\n\
1585 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1586 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1587 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1588 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1589 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1590 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1591 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1592 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1593 @end smallexample\n\
1595 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1596 to the priorities. As a result, instructions of same fusion type will be\n\
1597 pushed together in instruction flow, like:\n\
1603 ldr r16, [r2, 12]\n\
1608 @end smallexample\n\
1610 Now peephole2 pass can simply merge the two pairs of loads.\n\
1612 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1613 work, it is only enabled by default when peephole2 is in effect.\n\
1615 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1616 the hook implementation for how different fusion types are supported.",
1617 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1619 HOOK_VECTOR_END (sched)
1621 /* Functions relating to OpenMP and Cilk Plus SIMD clones. */
1623 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1624 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1627 (compute_vecsize_and_simdlen,
1628 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1629 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1630 @var{simdlen} field if it was previously 0.\n\
1631 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1632 or number of @var{vecsize_mangle} variants that should be emitted.",
1633 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1637 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1638 to SIMD clone @var{node} if needed.",
1639 void, (struct cgraph_node *), NULL)
1643 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1644 in vectorized loops in current function, or non-negative number if it is\n\
1645 usable. In that case, the smaller the number is, the more desirable it is\n\
1647 int, (struct cgraph_node *), NULL)
1649 HOOK_VECTOR_END (simd_clone)
1651 /* Functions relating to OpenMP SIMT vectorization transform. */
1653 #define HOOK_PREFIX "TARGET_SIMT_"
1654 HOOK_VECTOR (TARGET_SIMT, simt)
1658 "Return number of threads in SIMT thread group on the target.",
1661 HOOK_VECTOR_END (simt)
1663 /* Functions relating to openacc. */
1665 #define HOOK_PREFIX "TARGET_GOACC_"
1666 HOOK_VECTOR (TARGET_GOACC, goacc)
1670 "This hook should check the launch dimensions provided for an OpenACC\n\
1671 compute region, or routine. Defaulted values are represented as -1\n\
1672 and non-constant values as 0. The @var{fn_level} is negative for the\n\
1673 function corresponding to the compute region. For a routine is is the\n\
1674 outermost level at which partitioned execution may be spawned. The hook\n\
1675 should verify non-default values. If DECL is NULL, global defaults\n\
1676 are being validated and unspecified defaults should be filled in.\n\
1677 Diagnostics should be issued as appropriate. Return\n\
1678 true, if changes have been made. You must override this hook to\n\
1679 provide dimensions larger than 1.",
1680 bool, (tree decl, int *dims, int fn_level),
1681 default_goacc_validate_dims)
1685 "This hook should return the maximum size of a particular dimension,\n\
1686 or zero if unbounded.",
1688 default_goacc_dim_limit)
1692 "This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1693 function calls to target-specific gimple, or indicate whether they\n\
1694 should be retained. It is executed during the oacc_device_lower pass.\n\
1695 It should return true, if the call should be retained. It should\n\
1696 return false, if it is to be deleted (either because target-specific\n\
1697 gimple has been inserted before it, or there is no need for it).\n\
1698 The default hook returns false, if there are no RTL expanders for them.",
1699 bool, (gcall *call, const int *dims, bool is_fork),
1700 default_goacc_fork_join)
1704 "This hook is used by the oacc_transform pass to expand calls to the\n\
1705 @var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1706 instructions. @var{call} is gimple statement containing the call to\n\
1707 the function. This hook removes statement @var{call} after the\n\
1708 expanded sequence has been inserted. This hook is also responsible\n\
1709 for allocating any storage for reductions when necessary.",
1710 void, (gcall *call),
1711 default_goacc_reduction)
1713 HOOK_VECTOR_END (goacc)
1715 /* Functions relating to vectorization. */
1717 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1718 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1720 /* The following member value is a pointer to a function called
1721 by the vectorizer, and return the decl of the target builtin
1724 (builtin_mask_for_load,
1725 "This hook should return the DECL of a function @var{f} that given an\n\
1726 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1727 used to extract from two vectors the relevant data that resides in\n\
1728 @var{addr} in case @var{addr} is not properly aligned.\n\
1730 The autovectorizer, when vectorizing a load operation from an address\n\
1731 @var{addr} that may be unaligned, will generate two vector loads from\n\
1732 the two aligned addresses around @var{addr}. It then generates a\n\
1733 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1734 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1735 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1736 the third argument, @var{OFF}, defines how the data will be extracted\n\
1737 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1738 @var{v2}; otherwise, the returned vector is composed from the last\n\
1739 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1740 @var{OFF} elements of @var{v2}.\n\
1742 If this hook is defined, the autovectorizer will generate a call\n\
1743 to @var{f} (using the DECL tree that this hook returns) and will\n\
1744 use the return value of @var{f} as the argument @var{OFF} to\n\
1745 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1746 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1748 If this hook is not defined, then @var{addr} will be used as\n\
1749 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1750 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1753 /* Returns a built-in function that realizes the vectorized version of
1754 a target-independent function, or NULL_TREE if not available. */
1756 (builtin_vectorized_function,
1757 "This hook should return the decl of a function that implements the\n\
1758 vectorized variant of the function with the @code{combined_fn} code\n\
1759 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1760 The return type of the vectorized function shall be of vector type\n\
1761 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1762 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1763 default_builtin_vectorized_function)
1765 /* Returns a built-in function that realizes the vectorized version of
1766 a target-specific function, or NULL_TREE if not available. */
1768 (builtin_md_vectorized_function,
1769 "This hook should return the decl of a function that implements the\n\
1770 vectorized variant of target built-in function @code{fndecl}. The\n\
1771 return type of the vectorized function shall be of vector type\n\
1772 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1773 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1774 default_builtin_md_vectorized_function)
1776 /* Returns a function declaration for a builtin that realizes the
1777 vector conversion, or NULL_TREE if not available. */
1779 (builtin_conversion,
1780 "This hook should return the DECL of a function that implements conversion of the\n\
1781 input vector of type @var{src_type} to type @var{dest_type}.\n\
1782 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1783 specifies how the conversion is to be applied\n\
1784 (truncation, rounding, etc.).\n\
1786 If this hook is defined, the autovectorizer will use the\n\
1787 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1788 conversion. Otherwise, it will return @code{NULL_TREE}.",
1789 tree, (unsigned code, tree dest_type, tree src_type),
1790 default_builtin_vectorized_conversion)
1792 /* Cost of different vector/scalar statements in vectorization cost
1793 model. In case of misaligned vector loads and stores the cost depends
1794 on the data type and misalignment value. */
1796 (builtin_vectorization_cost,
1797 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1798 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1799 misalignment value (@var{misalign}).",
1800 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1801 default_builtin_vectorization_cost)
1803 /* Return true if vector alignment is reachable (by peeling N
1804 iterations) for the given type. */
1806 (vector_alignment_reachable,
1807 "Return true if vector alignment is reachable (by peeling N iterations) for the given type.",
1808 bool, (const_tree type, bool is_packed),
1809 default_builtin_vector_alignment_reachable)
1811 /* Return true if a vector created for vec_perm_const is valid.
1812 A NULL indicates that all constants are valid permutations. */
1815 "Return true if a vector created for @code{vec_perm_const} is valid.",
1816 bool, (machine_mode, const unsigned char *sel),
1819 /* Return true if the target supports misaligned store/load of a
1820 specific factor denoted in the third parameter. The last parameter
1821 is true if the access is defined in a packed struct. */
1823 (support_vector_misalignment,
1824 "This hook should return true if the target supports misaligned vector\n\
1825 store/load of a specific factor denoted in the @var{misalignment}\n\
1826 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1827 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1828 parameter is true if the memory access is defined in a packed struct.",
1830 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1831 default_builtin_support_vector_misalignment)
1833 /* Returns the preferred mode for SIMD operations for the specified
1836 (preferred_simd_mode,
1837 "This hook should return the preferred mode for vectorizing scalar\n\
1838 mode @var{mode}. The default is\n\
1839 equal to @code{word_mode}, because the vectorizer can do some\n\
1840 transformations even in absence of specialized @acronym{SIMD} hardware.",
1842 (machine_mode mode),
1843 default_preferred_simd_mode)
1845 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1846 after processing the preferred one derived from preferred_simd_mode. */
1848 (autovectorize_vector_sizes,
1849 "This hook should return a mask of sizes that should be iterated over\n\
1850 after trying to autovectorize using the vector size derived from the\n\
1851 mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1852 The default is zero which means to not iterate over other vector sizes.",
1855 default_autovectorize_vector_sizes)
1857 /* Function to get a target mode for a vector mask. */
1860 "This hook returns mode to be used for a mask to be used for a vector\n\
1861 of specified @var{length} with @var{nunits} elements. By default an integer\n\
1862 vector mode of a proper size is returned.",
1864 (unsigned nunits, unsigned length),
1865 default_get_mask_mode)
1867 /* Target builtin that implements vector gather operation. */
1870 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1871 is the vector type of the load and @var{index_type} is scalar type of\n\
1872 the index, scaled by @var{scale}.\n\
1873 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1876 (const_tree mem_vectype, const_tree index_type, int scale),
1879 /* Target builtin that implements vector scatter operation. */
1882 "Target builtin that implements vector scatter operation. @var{vectype}\n\
1883 is the vector type of the store and @var{index_type} is scalar type of\n\
1884 the index, scaled by @var{scale}.\n\
1885 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
1888 (const_tree vectype, const_tree index_type, int scale),
1891 /* Target function to initialize the cost model for a loop or block. */
1894 "This hook should initialize target-specific data structures in preparation "
1895 "for modeling the costs of vectorizing a loop or basic block. The default "
1896 "allocates three unsigned integers for accumulating costs for the prologue, "
1897 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1898 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1899 "is being vectorized.",
1901 (struct loop *loop_info),
1904 /* Target function to record N statements of the given kind using the
1905 given vector type within the cost model data for the current loop or
1909 "This hook should update the target-specific @var{data} in response to "
1910 "adding @var{count} copies of the given @var{kind} of statement to a "
1911 "loop or basic block. The default adds the builtin vectorizer cost for "
1912 "the copies of the statement to the accumulator specified by @var{where}, "
1913 "(the prologue, body, or epilogue) and returns the amount added. The "
1914 "return value should be viewed as a tentative cost that may later be "
1917 (void *data, int count, enum vect_cost_for_stmt kind,
1918 struct _stmt_vec_info *stmt_info, int misalign,
1919 enum vect_cost_model_location where),
1920 default_add_stmt_cost)
1922 /* Target function to calculate the total cost of the current vectorized
1926 "This hook should complete calculations of the cost of vectorizing a loop "
1927 "or basic block based on @var{data}, and return the prologue, body, and "
1928 "epilogue costs as unsigned integers. The default returns the value of "
1929 "the three accumulators.",
1931 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1932 unsigned *epilogue_cost),
1933 default_finish_cost)
1935 /* Function to delete target-specific cost modeling data. */
1938 "This hook should release @var{data} and any related data structures "
1939 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1943 default_destroy_cost_data)
1945 HOOK_VECTOR_END (vectorize)
1948 #define HOOK_PREFIX "TARGET_"
1951 (record_offload_symbol,
1952 "Used when offloaded functions are seen in the compilation unit and no named\n\
1953 sections are available. It is called once for each symbol that must be\n\
1954 recorded in the offload function and variable table.",
1959 (absolute_biggest_alignment,
1960 "If defined, this target hook specifies the absolute biggest alignment\n\
1961 that a type or variable can have on this machine, otherwise,\n\
1962 @code{BIGGEST_ALIGNMENT} is used.",
1963 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
1965 /* Allow target specific overriding of option settings after options have
1966 been changed by an attribute or pragma or when it is reset at the
1967 end of the code affected by an attribute or pragma. */
1969 (override_options_after_change,
1970 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
1971 but is called when the optimize level is changed via an attribute or\n\
1972 pragma or when it is reset at the end of the code affected by the\n\
1973 attribute or pragma. It is not called at the beginning of compilation\n\
1974 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
1975 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
1976 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
1982 "Used when writing out the list of options into an LTO file. It should\n\
1983 translate any relevant target-specific options (such as the ABI in use)\n\
1984 into one of the @option{-foffload} options that exist as a common interface\n\
1985 to express such options. It should return a string containing these options,\n\
1986 separated by spaces, which the caller will free.\n",
1987 char *, (void), hook_charptr_void_null)
1990 (eh_return_filter_mode,
1991 "Return machine mode for filter value.",
1992 machine_mode, (void),
1993 default_eh_return_filter_mode)
1995 /* Return machine mode for libgcc expanded cmp instructions. */
1997 (libgcc_cmp_return_mode,
1998 "This target hook should return the mode to be used for the return value\n\
1999 of compare instructions expanded to libgcc calls. If not defined\n\
2000 @code{word_mode} is returned which is the right choice for a majority of\n\
2002 machine_mode, (void),
2003 default_libgcc_cmp_return_mode)
2005 /* Return machine mode for libgcc expanded shift instructions. */
2007 (libgcc_shift_count_mode,
2008 "This target hook should return the mode to be used for the shift count operand\n\
2009 of shift instructions expanded to libgcc calls. If not defined\n\
2010 @code{word_mode} is returned which is the right choice for a majority of\n\
2012 machine_mode, (void),
2013 default_libgcc_shift_count_mode)
2015 /* Return machine mode to be used for _Unwind_Word type. */
2018 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2019 The default is to use @code{word_mode}.",
2020 machine_mode, (void),
2021 default_unwind_word_mode)
2023 /* Given two decls, merge their attributes and return the result. */
2025 (merge_decl_attributes,
2026 "Define this target hook if the merging of decl attributes needs special\n\
2027 handling. If defined, the result is a list of the combined\n\
2028 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2029 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2030 when this is needed are when one attribute overrides another, or when an\n\
2031 attribute is nullified by a subsequent definition. This function may\n\
2032 call @code{merge_attributes} to handle machine-independent merging.\n\
2034 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2035 If the only target-specific handling you require is @samp{dllimport}\n\
2036 for Microsoft Windows targets, you should define the macro\n\
2037 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2038 will then define a function called\n\
2039 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2040 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2041 add @code{handle_dll_attribute} in the attribute table for your port\n\
2042 to perform initial processing of the @samp{dllimport} and\n\
2043 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2044 @file{i386/i386.c}, for example.",
2045 tree, (tree olddecl, tree newdecl),
2046 merge_decl_attributes)
2048 /* Given two types, merge their attributes and return the result. */
2050 (merge_type_attributes,
2051 "Define this target hook if the merging of type attributes needs special\n\
2052 handling. If defined, the result is a list of the combined\n\
2053 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2054 that @code{comptypes} has already been called and returned 1. This\n\
2055 function may call @code{merge_attributes} to handle machine-independent\n\
2057 tree, (tree type1, tree type2),
2058 merge_type_attributes)
2060 /* Table of machine attributes and functions to handle them.
2064 "If defined, this target hook points to an array of @samp{struct\n\
2065 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2066 specific attributes for this target and some of the restrictions on the\n\
2067 entities to which these attributes are applied and the arguments they\n\
2069 const struct attribute_spec *, NULL)
2071 /* Return true iff attribute NAME expects a plain identifier as its first
2074 (attribute_takes_identifier_p,
2075 "If defined, this target hook is a function which returns true if the\n\
2076 machine-specific attribute named @var{name} expects an identifier\n\
2077 given as its first argument to be passed on as a plain identifier, not\n\
2078 subjected to name lookup. If this is not defined, the default is\n\
2079 false for all machine-specific attributes.",
2080 bool, (const_tree name),
2081 hook_bool_const_tree_false)
2083 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2084 one if they are compatible and two if they are nearly compatible
2085 (which causes a warning to be generated). */
2087 (comp_type_attributes,
2088 "If defined, this target hook is a function which returns zero if the attributes on\n\
2089 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2090 and two if they are nearly compatible (which causes a warning to be\n\
2091 generated). If this is not defined, machine-specific attributes are\n\
2092 supposed always to be compatible.",
2093 int, (const_tree type1, const_tree type2),
2094 hook_int_const_tree_const_tree_1)
2096 /* Assign default attributes to the newly defined TYPE. */
2098 (set_default_type_attributes,
2099 "If defined, this target hook is a function which assigns default attributes to\n\
2100 the newly defined @var{type}.",
2104 /* Insert attributes on the newly created DECL. */
2107 "Define this target hook if you want to be able to add attributes to a decl\n\
2108 when it is being created. This is normally useful for back ends which\n\
2109 wish to implement a pragma by using the attributes which correspond to\n\
2110 the pragma's effect. The @var{node} argument is the decl which is being\n\
2111 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2112 for this decl. The list itself should not be modified, since it may be\n\
2113 shared with other decls, but attributes may be chained on the head of\n\
2114 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2115 attributes, or a copy of the list may be made if further changes are\n\
2117 void, (tree node, tree *attr_ptr),
2118 hook_void_tree_treeptr)
2120 /* Return true if FNDECL (which has at least one machine attribute)
2121 can be inlined despite its machine attributes, false otherwise. */
2123 (function_attribute_inlinable_p,
2124 "@cindex inlining\n\
2125 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2126 into the current function, despite its having target-specific\n\
2127 attributes, @code{false} otherwise. By default, if a function has a\n\
2128 target specific attribute attached to it, it will not be inlined.",
2129 bool, (const_tree fndecl),
2130 hook_bool_const_tree_false)
2132 /* Return true if bitfields in RECORD_TYPE should follow the
2133 Microsoft Visual C++ bitfield layout rules. */
2135 (ms_bitfield_layout_p,
2136 "This target hook returns @code{true} if bit-fields in the given\n\
2137 @var{record_type} are to be laid out following the rules of Microsoft\n\
2138 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2139 unit with the previous bit-field if their underlying types have\n\
2140 different sizes, and the bit-field will be aligned to the highest\n\
2141 alignment of the underlying types of itself and of the previous\n\
2142 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2143 the whole enclosing structure, even if it is unnamed; except that\n\
2144 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2145 another bit-field of nonzero size. If this hook returns @code{true},\n\
2146 other macros that control bit-field layout are ignored.\n\
2148 When a bit-field is inserted into a packed record, the whole size\n\
2149 of the underlying type is used by one or more same-size adjacent\n\
2150 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2151 and any additional adjacent long bit-fields are packed into the same\n\
2152 chunk of 32 bits. However, if the size changes, a new field of that\n\
2153 size is allocated). In an unpacked record, this is the same as using\n\
2154 alignment, but not equivalent when packing.\n\
2156 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2157 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2158 used on a single field when MS bit-fields are in use, it will take\n\
2159 precedence for that field, but the alignment of the rest of the structure\n\
2160 may affect its placement.",
2161 bool, (const_tree record_type),
2162 hook_bool_const_tree_false)
2164 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2165 target-independent code like the front ends, need performance testing
2166 before switching completely to the target hook. */
2171 targhook_words_big_endian)
2173 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2175 (float_words_big_endian,
2178 targhook_float_words_big_endian)
2181 (float_exceptions_rounding_supported_p,
2182 "Returns true if the target supports IEEE 754 floating-point exceptions\
2183 and rounding modes, false otherwise. This is intended to relate to the\
2184 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2185 By default, returns true if the @code{adddf3} instruction pattern is\
2186 available and false otherwise, on the assumption that hardware floating\
2187 point supports exceptions and rounding modes but software floating point\
2190 default_float_exceptions_rounding_supported_p)
2192 /* True if the target supports decimal floating point. */
2194 (decimal_float_supported_p,
2195 "Returns true if the target supports decimal floating point.",
2197 default_decimal_float_supported_p)
2199 /* True if the target supports fixed-point. */
2201 (fixed_point_supported_p,
2202 "Returns true if the target supports fixed-point arithmetic.",
2204 default_fixed_point_supported_p)
2206 /* Return true if anonymous bitfields affect structure alignment. */
2208 (align_anon_bitfield,
2209 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2210 whether unnamed bitfields affect the alignment of the containing\n\
2211 structure. The hook should return true if the structure should inherit\n\
2212 the alignment requirements of an unnamed bitfield's type.",
2214 hook_bool_void_false)
2216 /* Return true if volatile bitfields should use the narrowest type possible.
2217 Return false if they should use the container type. */
2219 (narrow_volatile_bitfield,
2220 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2221 should use the narrowest mode possible. It should return @code{false} if\n\
2222 these accesses should use the bitfield container type.\n\
2224 The default is @code{false}.",
2226 hook_bool_void_false)
2228 /* Set up target-specific built-in functions. */
2231 "Define this hook if you have any machine-specific built-in functions\n\
2232 that need to be defined. It should be a function that performs the\n\
2235 Machine specific built-in functions can be useful to expand special machine\n\
2236 instructions that would otherwise not normally be generated because\n\
2237 they have no equivalent in the source language (for example, SIMD vector\n\
2238 instructions or prefetch instructions).\n\
2240 To create a built-in function, call the function\n\
2241 @code{lang_hooks.builtin_function}\n\
2242 which is defined by the language front end. You can use any type nodes set\n\
2243 up by @code{build_common_tree_nodes};\n\
2244 only language front ends that use those two functions will call\n\
2245 @samp{TARGET_INIT_BUILTINS}.",
2249 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2250 built-in function decl for CODE.
2251 Return NULL if that is not possible. Return error_mark_node if CODE
2252 is outside of the range of valid target builtin function codes. */
2255 "Define this hook if you have any machine-specific built-in functions\n\
2256 that need to be defined. It should be a function that returns the\n\
2257 builtin function declaration for the builtin function code @var{code}.\n\
2258 If there is no such builtin and it cannot be initialized at this time\n\
2259 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2260 If @var{code} is out of range the function should return\n\
2261 @code{error_mark_node}.",
2262 tree, (unsigned code, bool initialize_p), NULL)
2264 /* Expand a target-specific builtin. */
2268 Expand a call to a machine specific built-in function that was set up by\n\
2269 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2270 function call; the result should go to @var{target} if that is\n\
2271 convenient, and have mode @var{mode} if that is convenient.\n\
2272 @var{subtarget} may be used as the target for computing one of\n\
2273 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2274 ignored. This function should return the result of the call to the\n\
2275 built-in function.",
2277 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2278 default_expand_builtin)
2281 (builtin_chkp_function,
2282 "This hook allows target to redefine built-in functions used by\n\
2283 Pointer Bounds Checker for code instrumentation. Hook should return\n\
2284 fndecl of function implementing generic builtin whose code is\n\
2285 passed in @var{fcode}. Currently following built-in functions are\n\
2286 obtained using this hook:\n\
2287 @deftypefn {Built-in Function} __bounds_type __chkp_bndmk (const void *@var{lb}, size_t @var{size})\n\
2288 Function code - BUILT_IN_CHKP_BNDMK. This built-in function is used\n\
2289 by Pointer Bounds Checker to create bound values. @var{lb} holds low\n\
2290 bound of the resulting bounds. @var{size} holds size of created bounds.\n\
2293 @deftypefn {Built-in Function} void __chkp_bndstx (const void *@var{ptr}, __bounds_type @var{b}, const void **@var{loc})\n\
2294 Function code - @code{BUILT_IN_CHKP_BNDSTX}. This built-in function is used\n\
2295 by Pointer Bounds Checker to store bounds @var{b} for pointer @var{ptr}\n\
2296 when @var{ptr} is stored by address @var{loc}.\n\
2299 @deftypefn {Built-in Function} __bounds_type __chkp_bndldx (const void **@var{loc}, const void *@var{ptr})\n\
2300 Function code - @code{BUILT_IN_CHKP_BNDLDX}. This built-in function is used\n\
2301 by Pointer Bounds Checker to get bounds of pointer @var{ptr} loaded by\n\
2302 address @var{loc}.\n\
2305 @deftypefn {Built-in Function} void __chkp_bndcl (const void *@var{ptr}, __bounds_type @var{b})\n\
2306 Function code - @code{BUILT_IN_CHKP_BNDCL}. This built-in function is used\n\
2307 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2308 lower bound of bounds @var{b}.\n\
2311 @deftypefn {Built-in Function} void __chkp_bndcu (const void *@var{ptr}, __bounds_type @var{b})\n\
2312 Function code - @code{BUILT_IN_CHKP_BNDCU}. This built-in function is used\n\
2313 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2314 upper bound of bounds @var{b}.\n\
2317 @deftypefn {Built-in Function} __bounds_type __chkp_bndret (void *@var{ptr})\n\
2318 Function code - @code{BUILT_IN_CHKP_BNDRET}. This built-in function is used\n\
2319 by Pointer Bounds Checker to obtain bounds returned by a call statement.\n\
2320 @var{ptr} passed to built-in is @code{SSA_NAME} returned by the call.\n\
2323 @deftypefn {Built-in Function} __bounds_type __chkp_intersect (__bounds_type @var{b1}, __bounds_type @var{b2})\n\
2324 Function code - @code{BUILT_IN_CHKP_INTERSECT}. This built-in function\n\
2325 returns intersection of bounds @var{b1} and @var{b2}.\n\
2328 @deftypefn {Built-in Function} __bounds_type __chkp_narrow (const void *@var{ptr}, __bounds_type @var{b}, size_t @var{s})\n\
2329 Function code - @code{BUILT_IN_CHKP_NARROW}. This built-in function\n\
2330 returns intersection of bounds @var{b} and\n\
2331 [@var{ptr}, @var{ptr} + @var{s} - @code{1}].\n\
2334 @deftypefn {Built-in Function} size_t __chkp_sizeof (const void *@var{ptr})\n\
2335 Function code - @code{BUILT_IN_CHKP_SIZEOF}. This built-in function\n\
2336 returns size of object referenced by @var{ptr}. @var{ptr} is always\n\
2337 @code{ADDR_EXPR} of @code{VAR_DECL}. This built-in is used by\n\
2338 Pointer Bounds Checker when bounds of object cannot be computed statically\n\
2339 (e.g. object has incomplete type).\n\
2342 @deftypefn {Built-in Function} const void *__chkp_extract_lower (__bounds_type @var{b})\n\
2343 Function code - @code{BUILT_IN_CHKP_EXTRACT_LOWER}. This built-in function\n\
2344 returns lower bound of bounds @var{b}.\n\
2347 @deftypefn {Built-in Function} const void *__chkp_extract_upper (__bounds_type @var{b})\n\
2348 Function code - @code{BUILT_IN_CHKP_EXTRACT_UPPER}. This built-in function\n\
2349 returns upper bound of bounds @var{b}.\n\
2351 tree, (unsigned fcode),
2352 default_builtin_chkp_function)
2356 "Return type to be used for bounds",
2358 default_chkp_bound_type)
2362 "Return mode to be used for bounds.",
2363 enum machine_mode, (void),
2364 default_chkp_bound_mode)
2367 (chkp_make_bounds_constant,
2368 "Return constant used to statically initialize constant bounds\n\
2369 with specified lower bound @var{lb} and upper bounds @var{ub}.",
2370 tree, (HOST_WIDE_INT lb, HOST_WIDE_INT ub),
2371 default_chkp_make_bounds_constant)
2374 (chkp_initialize_bounds,
2375 "Generate a list of statements @var{stmts} to initialize pointer\n\
2376 bounds variable @var{var} with bounds @var{lb} and @var{ub}. Return\n\
2377 the number of generated statements.",
2378 int, (tree var, tree lb, tree ub, tree *stmts),
2379 default_chkp_initialize_bounds)
2381 /* Select a replacement for a target-specific builtin. This is done
2382 *before* regular type checking, and so allows the target to
2383 implement a crude form of function overloading. The result is a
2384 complete expression that implements the operation. PARAMS really
2385 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2387 (resolve_overloaded_builtin,
2388 "Select a replacement for a machine specific built-in function that\n\
2389 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2390 @emph{before} regular type checking, and so allows the target to\n\
2391 implement a crude form of function overloading. @var{fndecl} is the\n\
2392 declaration of the built-in function. @var{arglist} is the list of\n\
2393 arguments passed to the built-in function. The result is a\n\
2394 complete expression that implements the operation, usually\n\
2395 another @code{CALL_EXPR}.\n\
2396 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2397 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2399 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2403 "Fold a call to a machine specific built-in function that was set up by\n\
2404 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2405 built-in function. @var{n_args} is the number of arguments passed to\n\
2406 the function; the arguments themselves are pointed to by @var{argp}.\n\
2407 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2408 containing a simplified expression for the call's result. If\n\
2409 @var{ignore} is true the value will be ignored.",
2410 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2411 hook_tree_tree_int_treep_bool_null)
2413 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2415 (gimple_fold_builtin,
2416 "Fold a call to a machine specific built-in function that was set up\n\
2417 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2418 statement holding the function call. Returns true if any change\n\
2419 was made to the GIMPLE stream.",
2420 bool, (gimple_stmt_iterator *gsi),
2421 hook_bool_gsiptr_false)
2423 /* Target hook is used to compare the target attributes in two functions to
2424 determine which function's features get higher priority. This is used
2425 during function multi-versioning to figure out the order in which two
2426 versions must be dispatched. A function version with a higher priority
2427 is checked for dispatching earlier. DECL1 and DECL2 are
2428 the two function decls that will be compared. It returns positive value
2429 if DECL1 is higher priority, negative value if DECL2 is higher priority
2430 and 0 if they are the same. */
2432 (compare_version_priority,
2433 "This hook is used to compare the target attributes in two functions to\n\
2434 determine which function's features get higher priority. This is used\n\
2435 during function multi-versioning to figure out the order in which two\n\
2436 versions must be dispatched. A function version with a higher priority\n\
2437 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2438 the two function decls that will be compared.",
2439 int, (tree decl1, tree decl2), NULL)
2441 /* Target hook is used to generate the dispatcher logic to invoke the right
2442 function version at run-time for a given set of function versions.
2443 ARG points to the callgraph node of the dispatcher function whose body
2444 must be generated. */
2446 (generate_version_dispatcher_body,
2447 "This hook is used to generate the dispatcher logic to invoke the right\n\
2448 function version at run-time for a given set of function versions.\n\
2449 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2450 body must be generated.",
2451 tree, (void *arg), NULL)
2453 /* Target hook is used to get the dispatcher function for a set of function
2454 versions. The dispatcher function is called to invoke the right function
2455 version at run-time. DECL is one version from a set of semantically
2456 identical versions. */
2458 (get_function_versions_dispatcher,
2459 "This hook is used to get the dispatcher function for a set of function\n\
2460 versions. The dispatcher function is called to invoke the right function\n\
2461 version at run-time. @var{decl} is one version from a set of semantically\n\
2462 identical versions.",
2463 tree, (void *decl), NULL)
2465 /* Returns a code for a target-specific builtin that implements
2466 reciprocal of a target-specific function, or NULL_TREE if not available. */
2468 (builtin_reciprocal,
2469 "This hook should return the DECL of a function that implements the\n\
2470 reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2471 @code{NULL_TREE} if such a function is not available.",
2472 tree, (tree fndecl),
2473 default_builtin_reciprocal)
2475 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2476 string containing the C++ mangling for TYPE. In all other cases, return
2480 "If your target defines any fundamental types, or any types your target\n\
2481 uses should be mangled differently from the default, define this hook\n\
2482 to return the appropriate encoding for these types as part of a C++\n\
2483 mangled name. The @var{type} argument is the tree structure representing\n\
2484 the type to be mangled. The hook may be applied to trees which are\n\
2485 not target-specific fundamental types; it should return @code{NULL}\n\
2486 for all such types, as well as arguments it does not recognize. If the\n\
2487 return value is not @code{NULL}, it must point to a statically-allocated\n\
2490 Target-specific fundamental types might be new fundamental types or\n\
2491 qualified versions of ordinary fundamental types. Encode new\n\
2492 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2493 is the name used for the type in source code, and @var{n} is the\n\
2494 length of @var{name} in decimal. Encode qualified versions of\n\
2495 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2496 @var{name} is the name used for the type qualifier in source code,\n\
2497 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2498 code used to represent the unqualified version of this type. (See\n\
2499 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2500 codes.) In both cases the spaces are for clarity; do not include any\n\
2501 spaces in your string.\n\
2503 This hook is applied to types prior to typedef resolution. If the mangled\n\
2504 name for a particular type depends only on that type's main variant, you\n\
2505 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2508 The default version of this hook always returns @code{NULL}, which is\n\
2509 appropriate for a target that does not define any new fundamental\n\
2511 const char *, (const_tree type),
2512 hook_constcharptr_const_tree_null)
2514 /* Make any adjustments to libfunc names needed for this target. */
2517 "This hook should declare additional library routines or rename\n\
2518 existing ones, using the functions @code{set_optab_libfunc} and\n\
2519 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2520 @code{init_optabs} calls this macro after initializing all the normal\n\
2521 library routines.\n\
2523 The default is to do nothing. Most ports don't need to define this hook.",
2527 /* Add a __gnu_ prefix to library functions rather than just __. */
2529 (libfunc_gnu_prefix,
2530 "If false (the default), internal library routines start with two\n\
2531 underscores. If set to true, these routines start with @code{__gnu_}\n\
2532 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2533 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2534 is set to true, the @file{tm.h} file must also\n\
2535 @code{#define LIBGCC2_GNU_PREFIX}.",
2538 /* Given a decl, a section name, and whether the decl initializer
2539 has relocs, choose attributes for the section. */
2540 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2542 (section_type_flags,
2543 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2544 based on a variable or function decl, a section name, and whether or not the\n\
2545 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2546 null, in which case read-write data should be assumed.\n\
2548 The default version of this function handles choosing code vs data,\n\
2549 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2550 need to override this if your target has special flags that might be\n\
2551 set via @code{__attribute__}.",
2552 unsigned int, (tree decl, const char *name, int reloc),
2553 default_section_type_flags)
2557 "This hook determines whether a function from a class of functions\n\
2558 @var{fn_class} is present at the runtime.",
2559 bool, (enum function_class fn_class),
2560 default_libc_has_function)
2562 /* True if new jumps cannot be created, to replace existing ones or
2563 not, at the current point in the compilation. */
2565 (cannot_modify_jumps_p,
2566 "This target hook returns @code{true} past the point in which new jump\n\
2567 instructions could be created. On machines that require a register for\n\
2568 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2569 reload, so this target hook should be defined to a function such as:\n\
2573 cannot_modify_jumps_past_reload_p ()\n\
2575 return (reload_completed || reload_in_progress);\n\
2579 hook_bool_void_false)
2581 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2584 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2585 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2586 false, if it can't.\
2587 For example, on some targets, certain kinds of branches can't be made to\
2588 follow through a hot/cold partitioning.",
2589 bool, (const rtx_insn *follower, const rtx_insn *followee),
2590 hook_bool_const_rtx_insn_const_rtx_insn_true)
2592 /* Return a register class for which branch target register
2593 optimizations should be applied. */
2595 (branch_target_register_class,
2596 "This target hook returns a register class for which branch target register\n\
2597 optimizations should be applied. All registers in this class should be\n\
2598 usable interchangeably. After reload, registers in this class will be\n\
2599 re-allocated and loads will be hoisted out of loops and be subjected\n\
2600 to inter-block scheduling.",
2601 reg_class_t, (void),
2602 default_branch_target_register_class)
2604 /* Return true if branch target register optimizations should include
2605 callee-saved registers that are not already live during the current
2606 function. AFTER_PE_GEN is true if prologues and epilogues have
2607 already been generated. */
2609 (branch_target_register_callee_saved,
2610 "Branch target register optimization will by default exclude callee-saved\n\
2612 that are not already live during the current function; if this target hook\n\
2613 returns true, they will be included. The target code must than make sure\n\
2614 that all target registers in the class returned by\n\
2615 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2616 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2617 epilogues have already been generated. Note, even if you only return\n\
2618 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2619 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2620 to reserve space for caller-saved target registers.",
2621 bool, (bool after_prologue_epilogue_gen),
2622 hook_bool_bool_false)
2624 /* Return true if the target supports conditional execution. */
2626 (have_conditional_execution,
2627 "This target hook returns true if the target supports conditional execution.\n\
2628 This target hook is required only when the target has several different\n\
2629 modes and they have different conditional execution capability, such as ARM.",
2631 default_have_conditional_execution)
2635 "This function prepares to emit a comparison insn for the first compare in a\n\
2636 sequence of conditional comparisions. It returns an appropriate comparison\n\
2637 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2638 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2639 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2640 compares in the the conditional comparision are generated without error.\n\
2641 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2642 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, int code, tree op0, tree op1),
2647 "This function prepares to emit a conditional comparison within a sequence\n\
2648 of conditional comparisons. It returns an appropriate comparison with\n\
2649 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2650 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2651 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2652 compares in the conditional comparision are generated without error. The\n\
2653 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2654 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2655 @var{prev} and this comparison is not supported, otherwise the result must\n\
2656 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2657 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2658 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2659 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2662 /* Return a new value for loop unroll size. */
2664 (loop_unroll_adjust,
2665 "This target hook returns a new value for the number of times @var{loop}\n\
2666 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2667 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2668 the loop, which is going to be checked for unrolling. This target hook\n\
2669 is required only when the target has special constraints like maximum\n\
2670 number of memory accesses.",
2671 unsigned, (unsigned nunroll, struct loop *loop),
2674 /* True if X is a legitimate MODE-mode immediate operand. */
2676 (legitimate_constant_p,
2677 "This hook returns true if @var{x} is a legitimate constant for a\n\
2678 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2679 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2681 The default definition returns true.",
2682 bool, (machine_mode mode, rtx x),
2683 hook_bool_mode_rtx_true)
2685 /* True if the constant X cannot be placed in the constant pool. */
2687 (cannot_force_const_mem,
2688 "This hook should return true if @var{x} is of a form that cannot (or\n\
2689 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2692 The default version of this hook returns false.\n\
2694 The primary reason to define this hook is to prevent reload from\n\
2695 deciding that a non-legitimate constant would be better reloaded\n\
2696 from the constant pool instead of spilling and reloading a register\n\
2697 holding the constant. This restriction is often true of addresses\n\
2698 of TLS symbols for various targets.",
2699 bool, (machine_mode mode, rtx x),
2700 hook_bool_mode_rtx_false)
2703 (cannot_copy_insn_p,
2704 "True if the insn @var{x} cannot be duplicated.",
2705 bool, (rtx_insn *), NULL)
2707 /* True if X is considered to be commutative. */
2710 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2711 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2712 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2713 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2714 bool, (const_rtx x, int outer_code),
2715 hook_bool_const_rtx_commutative_p)
2717 /* True if ADDR is an address-expression whose effect depends
2718 on the mode of the memory reference it is used in. */
2720 (mode_dependent_address_p,
2721 "This hook returns @code{true} if memory address @var{addr} in address\n\
2722 space @var{addrspace} can have\n\
2723 different meanings depending on the machine mode of the memory\n\
2724 reference it is used for or if the address is valid for some modes\n\
2727 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2728 effects because the amount of the increment or decrement is the size\n\
2729 of the operand being addressed. Some machines have other mode-dependent\n\
2730 addresses. Many RISC machines have no mode-dependent addresses.\n\
2732 You may assume that @var{addr} is a valid address for the machine.\n\
2734 The default version of this hook returns @code{false}.",
2735 bool, (const_rtx addr, addr_space_t addrspace),
2736 default_mode_dependent_address_p)
2738 /* Given an invalid address X for a given machine mode, try machine-specific
2739 ways to make it legitimate. Return X or an invalid address on failure. */
2741 (legitimize_address,
2742 "This hook is given an invalid memory address @var{x} for an\n\
2743 operand of mode @var{mode} and should try to return a valid memory\n\
2746 @findex break_out_memory_refs\n\
2747 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2748 and @var{oldx} will be the operand that was given to that function to produce\n\
2751 The code of the hook should not alter the substructure of\n\
2752 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2753 should return the new @var{x}.\n\
2755 It is not necessary for this hook to come up with a legitimate address,\n\
2756 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2757 The compiler has standard ways of doing so in all cases. In fact, if\n\
2758 the target supports only emulated TLS, it\n\
2759 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2760 a valid way to legitimize the address. But often a machine-dependent\n\
2761 strategy can generate better code.",
2762 rtx, (rtx x, rtx oldx, machine_mode mode),
2763 default_legitimize_address)
2765 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2767 (delegitimize_address,
2768 "This hook is used to undo the possibly obfuscating effects of the\n\
2769 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2770 macros. Some backend implementations of these macros wrap symbol\n\
2771 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2772 addressing modes. This target hook allows GCC's optimizers to understand\n\
2773 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2774 into their original form.",
2776 delegitimize_mem_from_attrs)
2778 /* Given an RTX, return true if it is not ok to emit it into debug info
2781 (const_not_ok_for_debug_p,
2782 "This hook should return true if @var{x} should not be emitted into\n\
2785 hook_bool_rtx_false)
2787 /* Given an address RTX, say whether it is valid. */
2789 (legitimate_address_p,
2790 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2791 address on the target machine for a memory operand of mode @var{mode}.\n\
2793 Legitimate addresses are defined in two variants: a strict variant and a\n\
2794 non-strict one. The @var{strict} parameter chooses which variant is\n\
2795 desired by the caller.\n\
2797 The strict variant is used in the reload pass. It must be defined so\n\
2798 that any pseudo-register that has not been allocated a hard register is\n\
2799 considered a memory reference. This is because in contexts where some\n\
2800 kind of register is required, a pseudo-register with no hard register\n\
2801 must be rejected. For non-hard registers, the strict variant should look\n\
2802 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2803 register number in the array, or treat the pseudo as a memory reference\n\
2804 if the array holds @code{-1}.\n\
2806 The non-strict variant is used in other passes. It must be defined to\n\
2807 accept all pseudo-registers in every context where some kind of\n\
2808 register is required.\n\
2810 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2811 and an integer are stored inside a @code{const} RTX to mark them as\n\
2812 constant. Therefore, there is no need to recognize such sums\n\
2813 specifically as legitimate addresses. Normally you would simply\n\
2814 recognize any @code{const} as legitimate.\n\
2816 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2817 sums that are not marked with @code{const}. It assumes that a naked\n\
2818 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2819 naked constant sums as illegitimate addresses, so that none of them will\n\
2820 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2822 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2823 On some machines, whether a symbolic address is legitimate depends on\n\
2824 the section that the address refers to. On these machines, define the\n\
2825 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2826 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2827 @code{const}, you will have to look inside it to find the\n\
2828 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2831 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2832 Some ports are still using a deprecated legacy substitute for\n\
2833 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2837 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2841 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2842 address on the target machine for a memory operand of mode @var{mode}.\n\
2844 @findex REG_OK_STRICT\n\
2845 Compiler source files that want to use the strict variant of this\n\
2846 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2847 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2848 that case and the non-strict variant otherwise.\n\
2850 Using the hook is usually simpler because it limits the number of\n\
2851 files that are recompiled when changes are made.",
2852 bool, (machine_mode mode, rtx x, bool strict),
2853 default_legitimate_address_p)
2855 /* True if the given constant can be put into an object_block. */
2857 (use_blocks_for_constant_p,
2858 "This hook should return true if pool entries for constant @var{x} can\n\
2859 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2862 The default version returns false for all constants.",
2863 bool, (machine_mode mode, const_rtx x),
2864 hook_bool_mode_const_rtx_false)
2866 /* True if the given decl can be put into an object_block. */
2868 (use_blocks_for_decl_p,
2869 "This hook should return true if pool entries for @var{decl} should\n\
2870 be placed in an @code{object_block} structure.\n\
2872 The default version returns true for all decls.",
2873 bool, (const_tree decl),
2874 hook_bool_const_tree_true)
2876 /* The minimum and maximum byte offsets for anchored addresses. */
2879 "The minimum offset that should be applied to a section anchor.\n\
2880 On most targets, it should be the smallest offset that can be\n\
2881 applied to a base register while still giving a legitimate address\n\
2882 for every mode. The default value is 0.",
2887 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2888 offset that should be applied to section anchors. The default\n\
2892 /* True if section anchors can be used to access the given symbol. */
2894 (use_anchors_for_symbol_p,
2895 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2896 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2897 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2899 The default version is correct for most targets, but you might need to\n\
2900 intercept this hook to handle things like target-specific attributes\n\
2901 or target-specific sections.",
2902 bool, (const_rtx x),
2903 default_use_anchors_for_symbol_p)
2905 /* True if target supports indirect functions. */
2908 "It returns true if the target supports GNU indirect functions.\n\
2909 The support includes the assembler, linker and dynamic linker.\n\
2910 The default value of this hook is based on target's libc.",
2912 default_has_ifunc_p)
2914 /* True if it is OK to do sibling call optimization for the specified
2915 call expression EXP. DECL will be the called function, or NULL if
2916 this is an indirect call. */
2918 (function_ok_for_sibcall,
2919 "True if it is OK to do sibling call optimization for the specified\n\
2920 call expression @var{exp}. @var{decl} will be the called function,\n\
2921 or @code{NULL} if this is an indirect call.\n\
2923 It is not uncommon for limitations of calling conventions to prevent\n\
2924 tail calls to functions outside the current unit of translation, or\n\
2925 during PIC compilation. The hook is used to enforce these restrictions,\n\
2926 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2927 ``normal'' call. The criteria for successful sibling call optimization\n\
2928 may vary greatly between different architectures.",
2929 bool, (tree decl, tree exp),
2930 hook_bool_tree_tree_false)
2932 /* Establish appropriate back-end context for processing the function
2933 FNDECL. The argument might be NULL to indicate processing at top
2934 level, outside of any function scope. */
2936 (set_current_function,
2937 "The compiler invokes this hook whenever it changes its current function\n\
2938 context (@code{cfun}). You can define this function if\n\
2939 the back end needs to perform any initialization or reset actions on a\n\
2940 per-function basis. For example, it may be used to implement function\n\
2941 attributes that affect register usage or code generation patterns.\n\
2942 The argument @var{decl} is the declaration for the new function context,\n\
2943 and may be null to indicate that the compiler has left a function context\n\
2944 and is returning to processing at the top level.\n\
2945 The default hook function does nothing.\n\
2947 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2948 some parts of the back end. The hook function is not invoked in this\n\
2949 situation; you need not worry about the hook being invoked recursively,\n\
2950 or when the back end is in a partially-initialized state.\n\
2951 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2952 outside of any function scope.",
2953 void, (tree decl), hook_void_tree)
2955 /* True if EXP should be placed in a "small data" section. */
2958 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2959 The default version of this hook always returns false.",
2960 bool, (const_tree exp),
2961 hook_bool_const_tree_false)
2963 /* True if EXP names an object for which name resolution must resolve
2964 to the current executable or shared library. */
2967 "Returns true if @var{exp} names an object for which name resolution\n\
2968 rules must resolve to the current ``module'' (dynamic shared library\n\
2969 or executable image).\n\
2971 The default version of this hook implements the name resolution rules\n\
2972 for ELF, which has a looser model of global name binding than other\n\
2973 currently supported object file formats.",
2974 bool, (const_tree exp),
2975 default_binds_local_p)
2977 /* Check if profiling code is before or after prologue. */
2979 (profile_before_prologue,
2980 "It returns true if target wants profile code emitted before prologue.\n\n\
2981 The default version of this hook use the target macro\n\
2982 @code{PROFILE_BEFORE_PROLOGUE}.",
2984 default_profile_before_prologue)
2986 /* Return true if a leaf function should stay leaf even with profiling
2989 (keep_leaf_when_profiled,
2990 "This target hook returns true if the target wants the leaf flag for\
2991 the current function to stay true even if it calls mcount. This might\
2992 make sense for targets using the leaf flag only to determine whether a\
2993 stack frame needs to be generated or not and for which the call to\
2994 mcount is generated before the function prologue.",
2996 default_keep_leaf_when_profiled)
2998 /* Modify and return the identifier of a DECL's external name,
2999 originally identified by ID, as required by the target,
3000 (eg, append @nn to windows32 stdcall function names).
3001 The default is to return ID without modification. */
3003 (mangle_decl_assembler_name,
3004 "Define this hook if you need to postprocess the assembler name generated\n\
3005 by target-independent code. The @var{id} provided to this hook will be\n\
3006 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3007 or the mangled name of the @var{decl} in C++). The return value of the\n\
3008 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3009 your target system. The default implementation of this hook just\n\
3010 returns the @var{id} provided.",
3011 tree, (tree decl, tree id),
3012 default_mangle_decl_assembler_name)
3014 /* Do something target-specific to record properties of the DECL into
3015 the associated SYMBOL_REF. */
3017 (encode_section_info,
3018 "Define this hook if references to a symbol or a constant must be\n\
3019 treated differently depending on something about the variable or\n\
3020 function named by the symbol (such as what section it is in).\n\
3022 The hook is executed immediately after rtl has been created for\n\
3023 @var{decl}, which may be a variable or function declaration or\n\
3024 an entry in the constant pool. In either case, @var{rtl} is the\n\
3025 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3026 in this hook; that field may not have been initialized yet.\n\
3028 In the case of a constant, it is safe to assume that the rtl is\n\
3029 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3030 will also have this form, but that is not guaranteed. Global\n\
3031 register variables, for instance, will have a @code{reg} for their\n\
3032 rtl. (Normally the right thing to do with such unusual rtl is\n\
3035 The @var{new_decl_p} argument will be true if this is the first time\n\
3036 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3037 be false for subsequent invocations, which will happen for duplicate\n\
3038 declarations. Whether or not anything must be done for the duplicate\n\
3039 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3040 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3042 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3043 The usual thing for this hook to do is to record flags in the\n\
3044 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3045 Historically, the name string was modified if it was necessary to\n\
3046 encode more than one bit of information, but this practice is now\n\
3047 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3049 The default definition of this hook, @code{default_encode_section_info}\n\
3050 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
3051 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3052 before overriding it.",
3053 void, (tree decl, rtx rtl, int new_decl_p),
3054 default_encode_section_info)
3056 /* Undo the effects of encode_section_info on the symbol string. */
3058 (strip_name_encoding,
3059 "Decode @var{name} and return the real name part, sans\n\
3060 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3062 const char *, (const char *name),
3063 default_strip_name_encoding)
3065 /* If shift optabs for MODE are known to always truncate the shift count,
3066 return the mask that they apply. Return 0 otherwise. */
3068 (shift_truncation_mask,
3069 "This function describes how the standard shift patterns for @var{mode}\n\
3070 deal with shifts by negative amounts or by more than the width of the mode.\n\
3071 @xref{shift patterns}.\n\
3073 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3074 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3075 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3076 this is true for mode @var{mode}, the function should return @var{m},\n\
3077 otherwise it should return 0. A return value of 0 indicates that no\n\
3078 particular behavior is guaranteed.\n\
3080 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3081 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3082 that are generated by the named shift patterns.\n\
3084 The default implementation of this function returns\n\
3085 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3086 and 0 otherwise. This definition is always safe, but if\n\
3087 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3088 nevertheless truncate the shift count, you may get better code\n\
3090 unsigned HOST_WIDE_INT, (machine_mode mode),
3091 default_shift_truncation_mask)
3093 /* Return the number of divisions in the given MODE that should be present,
3094 so that it is profitable to turn the division into a multiplication by
3097 (min_divisions_for_recip_mul,
3098 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3099 divisions by the same divisor, by turning them into multiplications by\n\
3100 the reciprocal. This target hook specifies the minimum number of divisions\n\
3101 that should be there for GCC to perform the optimization for a variable\n\
3102 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3103 has an instruction for the division, and 2 if it does not.",
3104 unsigned int, (machine_mode mode),
3105 default_min_divisions_for_recip_mul)
3107 /* If the representation of integral MODE is such that values are
3108 always sign-extended to a wider mode MODE_REP then return
3109 SIGN_EXTEND. Return UNKNOWN otherwise. */
3110 /* Note that the return type ought to be RTX_CODE, but that's not
3111 necessarily defined at this point. */
3114 "The representation of an integral mode can be such that the values\n\
3115 are always extended to a wider integral mode. Return\n\
3116 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3117 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3118 otherwise. (Currently, none of the targets use zero-extended\n\
3119 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3120 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3121 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3122 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3123 widest integral mode and currently we take advantage of this fact.)\n\
3125 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3126 value even if the extension is not performed on certain hard registers\n\
3127 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3128 @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.\n\
3130 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3131 describe two related properties. If you define\n\
3132 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3133 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3136 In order to enforce the representation of @code{mode},\n\
3137 @code{TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3139 int, (machine_mode mode, machine_mode rep_mode),
3140 default_mode_rep_extended)
3142 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3144 (valid_pointer_mode,
3145 "Define this to return nonzero if the port can handle pointers\n\
3146 with machine mode @var{mode}. The default version of this\n\
3147 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3148 bool, (machine_mode mode),
3149 default_valid_pointer_mode)
3151 /* Disambiguate with errno. */
3153 (ref_may_alias_errno,
3154 "Define this to return nonzero if the memory reference @var{ref}\
3155 may alias with the system C library errno location. The default\
3156 version of this hook assumes the system C library errno location\
3157 is either a declaration of type int or accessed by dereferencing\
3159 bool, (struct ao_ref *ref),
3160 default_ref_may_alias_errno)
3162 /* Support for named address spaces. */
3164 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3165 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3167 /* MODE to use for a pointer into another address space. */
3170 "Define this to return the machine mode to use for pointers to\n\
3171 @var{address_space} if the target supports named address spaces.\n\
3172 The default version of this hook returns @code{ptr_mode}.",
3173 machine_mode, (addr_space_t address_space),
3174 default_addr_space_pointer_mode)
3176 /* MODE to use for an address in another address space. */
3179 "Define this to return the machine mode to use for addresses in\n\
3180 @var{address_space} if the target supports named address spaces.\n\
3181 The default version of this hook returns @code{Pmode}.",
3182 machine_mode, (addr_space_t address_space),
3183 default_addr_space_address_mode)
3185 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3186 in another address space. */
3188 (valid_pointer_mode,
3189 "Define this to return nonzero if the port can handle pointers\n\
3190 with machine mode @var{mode} to address space @var{as}. This target\n\
3191 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3192 except that it includes explicit named address space support. The default\n\
3193 version of this hook returns true for the modes returned by either the\n\
3194 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3195 target hooks for the given address space.",
3196 bool, (machine_mode mode, addr_space_t as),
3197 default_addr_space_valid_pointer_mode)
3199 /* True if an address is a valid memory address to a given named address
3200 space for a given mode. */
3202 (legitimate_address_p,
3203 "Define this to return true if @var{exp} is a valid address for mode\n\
3204 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3205 parameter says whether strict addressing is in effect after reload has\n\
3206 finished. This target hook is the same as the\n\
3207 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3208 explicit named address space support.",
3209 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3210 default_addr_space_legitimate_address_p)
3212 /* Return an updated address to convert an invalid pointer to a named
3213 address space to a valid one. If NULL_RTX is returned use machine
3214 independent methods to make the address valid. */
3216 (legitimize_address,
3217 "Define this to modify an invalid address @var{x} to be a valid address\n\
3218 with mode @var{mode} in the named address space @var{as}. This target\n\
3219 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3220 except that it includes explicit named address space support.",
3221 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3222 default_addr_space_legitimize_address)
3224 /* True if one named address space is a subset of another named address. */
3227 "Define this to return whether the @var{subset} named address space is\n\
3228 contained within the @var{superset} named address space. Pointers to\n\
3229 a named address space that is a subset of another named address space\n\
3230 will be converted automatically without a cast if used together in\n\
3231 arithmetic operations. Pointers to a superset address space can be\n\
3232 converted to pointers to a subset address space via explicit casts.",
3233 bool, (addr_space_t subset, addr_space_t superset),
3234 default_addr_space_subset_p)
3236 /* True if 0 is a valid address in the address space, or false if
3237 0 is a NULL in the address space. */
3239 (zero_address_valid,
3240 "Define this to modify the default handling of address 0 for the\n\
3241 address space. Return true if 0 should be considered a valid address.",
3242 bool, (addr_space_t as),
3243 default_addr_space_zero_address_valid)
3245 /* Function to convert an rtl expression from one address space to another. */
3248 "Define this to convert the pointer expression represented by the RTL\n\
3249 @var{op} with type @var{from_type} that points to a named address\n\
3250 space to a new pointer expression with type @var{to_type} that points\n\
3251 to a different named address space. When this hook it called, it is\n\
3252 guaranteed that one of the two address spaces is a subset of the other,\n\
3253 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3254 rtx, (rtx op, tree from_type, tree to_type),
3255 default_addr_space_convert)
3257 /* Function to encode an address space into dwarf. */
3260 "Define this to define how the address space is encoded in dwarf.\n\
3261 The result is the value to be used with @code{DW_AT_address_class}.",
3262 int, (addr_space_t as),
3263 default_addr_space_debug)
3265 /* Function to emit custom diagnostic if an address space is used. */
3268 "Define this hook if the availability of an address space depends on\n\
3269 command line options and some diagnostics should be printed when the\n\
3270 address space is used. This hook is called during parsing and allows\n\
3271 to emit a better diagnostic compared to the case where the address space\n\
3272 was not registered with @code{c_register_addr_space}. @var{as} is\n\
3273 the address space as registered with @code{c_register_addr_space}.\n\
3274 @var{loc} is the location of the address space qualifier token.\n\
3275 The default implementation does nothing.",
3276 void, (addr_space_t as, location_t loc),
3277 default_addr_space_diagnose_usage)
3279 HOOK_VECTOR_END (addr_space)
3282 #define HOOK_PREFIX "TARGET_"
3284 /* True if MODE is valid for the target. By "valid", we mean able to
3285 be manipulated in non-trivial ways. In particular, this means all
3286 the arithmetic is supported. */
3288 (scalar_mode_supported_p,
3289 "Define this to return nonzero if the port is prepared to handle\n\
3290 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3291 considered supported, all the basic arithmetic and comparisons\n\
3294 The default version of this hook returns true for any mode\n\
3295 required to handle the basic C types (as defined by the port).\n\
3296 Included here are the double-word arithmetic supported by the\n\
3297 code in @file{optabs.c}.",
3298 bool, (machine_mode mode),
3299 default_scalar_mode_supported_p)
3301 /* Similarly for vector modes. "Supported" here is less strict. At
3302 least some operations are supported; need to check optabs or builtins
3303 for further details. */
3305 (vector_mode_supported_p,
3306 "Define this to return nonzero if the port is prepared to handle\n\
3307 insns involving vector mode @var{mode}. At the very least, it\n\
3308 must have move patterns for this mode.",
3309 bool, (machine_mode mode),
3310 hook_bool_mode_false)
3314 "This hook can be used to define the alignment for a vector of type\n\
3315 @var{type}, in order to comply with a platform ABI. The default is to\n\
3316 require natural alignment for vector types. The alignment returned by\n\
3317 this hook must be a power-of-two multiple of the default alignment of\n\
3318 the vector element type.",
3319 HOST_WIDE_INT, (const_tree type),
3320 default_vector_alignment)
3322 /* True if we should try to use a scalar mode to represent an array,
3323 overriding the usual MAX_FIXED_MODE limit. */
3325 (array_mode_supported_p,
3326 "Return true if GCC should try to use a scalar mode to store an array\n\
3327 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3328 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3329 and allows GCC to use any defined integer mode.\n\
3331 One use of this hook is to support vector load and store operations\n\
3332 that operate on several homogeneous vectors. For example, ARM NEON\n\
3333 has operations like:\n\
3336 int8x8x3_t vld3_s8 (const int8_t *)\n\
3337 @end smallexample\n\
3339 where the return type is defined as:\n\
3342 typedef struct int8x8x3_t\n\
3346 @end smallexample\n\
3348 If this hook allows @code{val} to have a scalar mode, then\n\
3349 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3350 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3351 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3352 hook_bool_mode_uhwi_false)
3355 (libgcc_floating_mode_supported_p,
3356 "Define this to return nonzero if libgcc provides support for the \n\
3357 floating-point mode @var{mode}, which is known to pass \n\
3358 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3359 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3360 @code{XFmode} and @code{TFmode}, if such modes exist.",
3361 bool, (machine_mode mode),
3362 default_libgcc_floating_mode_supported_p)
3366 "Define this to return the machine mode to use for the type \n\
3367 @code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3368 @code{_Float@var{n}x}, if @var{extended} is true. If such a type \n\
3369 is not supported, return @code{VOIDmode}. The default version of this \n\
3370 hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for \n\
3371 @code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3372 @code{_Float128}, if those modes exist and satisfy the requirements for \n\
3373 those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3374 @code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3375 returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3376 satisfies the same requirements; for other types, it returns \n\
3377 @code{VOIDmode}. The hook is only called for values of @var{n} and \n\
3378 @var{extended} that are valid according to ISO/IEC TS 18661-3:2015; that \n\
3379 is, @var{n} is one of 32, 64, 128, or, if @var{extended} is false, 16 or \n\
3380 greater than 128 and a multiple of 32.",
3381 machine_mode, (int n, bool extended),
3382 default_floatn_mode)
3385 (printf_pointer_format,
3386 "Determine the target @code{printf} implementation format string that the most closely corresponds to the @code{%p} format directive. The object pointed to by the @var{flags} is set to a string consisting of recognized format flags such as the @code{'#'} character.",
3387 const char*, (tree, const char **flags),
3388 default_printf_pointer_format)
3390 /* Compute cost of moving data from a register of class FROM to one of
3393 (register_move_cost,
3394 "This target hook should return the cost of moving data of mode @var{mode}\n\
3395 from a register in class @var{from} to one in class @var{to}. The classes\n\
3396 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3397 A value of 2 is the default; other values are interpreted relative to\n\
3400 It is not required that the cost always equal 2 when @var{from} is the\n\
3401 same as @var{to}; on some machines it is expensive to move between\n\
3402 registers if they are not general registers.\n\
3404 If reload sees an insn consisting of a single @code{set} between two\n\
3405 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3406 classes returns a value of 2, reload does not check to ensure that the\n\
3407 constraints of the insn are met. Setting a cost of other than 2 will\n\
3408 allow reload to verify that the constraints are met. You should do this\n\
3409 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3411 The default version of this function returns 2.",
3412 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3413 default_register_move_cost)
3415 /* Compute cost of moving registers to/from memory. */
3416 /* ??? Documenting the argument types for this hook requires a GFDL
3417 license grant. Also, the documentation uses a different name for RCLASS. */
3420 "This target hook should return the cost of moving data of mode @var{mode}\n\
3421 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3422 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3423 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3424 If moving between registers and memory is more expensive than between two\n\
3425 registers, you should add this target hook to express the relative cost.\n\
3427 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3428 the cost of copying via a secondary reload register, if one is\n\
3429 needed. If your machine requires a secondary reload register to copy\n\
3430 between memory and a register of @var{rclass} but the reload mechanism is\n\
3431 more complex than copying via an intermediate, use this target hook to\n\
3432 reflect the actual cost of the move.\n\
3434 GCC defines the function @code{memory_move_secondary_cost} if\n\
3435 secondary reloads are needed. It computes the costs due to copying via\n\
3436 a secondary register. If your machine copies from memory using a\n\
3437 secondary register in the conventional way but the default base value of\n\
3438 4 is not correct for your machine, use this target hook to add some other\n\
3439 value to the result of that function. The arguments to that function\n\
3440 are the same as to this target hook.",
3441 int, (machine_mode mode, reg_class_t rclass, bool in),
3442 default_memory_move_cost)
3445 (use_by_pieces_infrastructure_p,
3446 "GCC will attempt several strategies when asked to copy between\n\
3447 two areas of memory, or to set, clear or store to memory, for example\n\
3448 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3449 implements such memory operations as a sequence of load, store or move\n\
3450 insns. Alternate strategies are to expand the\n\
3451 @code{movmem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3452 unit-by-unit, loop-based operations.\n\
3454 This target hook should return true if, for a memory operation with a\n\
3455 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3456 infrastructure is expected to result in better code generation.\n\
3457 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3460 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3461 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3462 @code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3463 under consideration.\n\
3465 The parameter @var{speed_p} is true if the code is currently being\n\
3466 optimized for speed rather than size.\n\
3468 Returning true for higher values of @var{size} can improve code generation\n\
3469 for speed if the target does not provide an implementation of the\n\
3470 @code{movmem} or @code{setmem} standard names, if the @code{movmem} or\n\
3471 @code{setmem} implementation would be more expensive than a sequence of\n\
3472 insns, or if the overhead of a library call would dominate that of\n\
3473 the body of the memory operation.\n\
3475 Returning true for higher values of @code{size} may also cause an increase\n\
3476 in code size, for example where the number of insns emitted to perform a\n\
3477 move would be greater than that of a library call.",
3478 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3479 enum by_pieces_operation op, bool speed_p),
3480 default_use_by_pieces_infrastructure_p)
3483 (compare_by_pieces_branch_ratio,
3484 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3485 number of branches at the expense of more memory operations. This hook\n\
3486 allows the target to override the default choice. It should return the\n\
3487 factor by which branches should be reduced over the plain expansion with\n\
3488 one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3489 particular mode from being used for block comparisons by returning a\n\
3490 negative number from this hook.",
3491 int, (machine_mode mode),
3492 default_compare_by_pieces_branch_ratio)
3496 "Return true if the optimizers should use optab @var{op} with\n\
3497 modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3498 The optab is known to have an associated @file{.md} instruction\n\
3499 whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3500 optabs; for direct optabs it is a copy of @var{mode1}.\n\
3502 For example, when called with @var{op} equal to @code{rint_optab} and\n\
3503 @var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3504 optimizers should use optab @code{rintdf2}.\n\
3506 The default hook returns true for all inputs.",
3507 bool, (int op, machine_mode mode1, machine_mode mode2,
3508 optimization_type opt_type),
3509 default_optab_supported_p)
3511 /* True for MODE if the target expects that registers in this mode will
3512 be allocated to registers in a small register class. The compiler is
3513 allowed to use registers explicitly used in the rtl as spill registers
3514 but it should prevent extending the lifetime of these registers. */
3516 (small_register_classes_for_mode_p,
3517 "Define this to return nonzero for machine modes for which the port has\n\
3518 small register classes. If this target hook returns nonzero for a given\n\
3519 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3520 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3521 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3524 On some machines, it is risky to let hard registers live across arbitrary\n\
3525 insns. Typically, these machines have instructions that require values\n\
3526 to be in specific registers (like an accumulator), and reload will fail\n\
3527 if the required hard register is used for another purpose across such an\n\
3530 Passes before reload do not know which hard registers will be used\n\
3531 in an instruction, but the machine modes of the registers set or used in\n\
3532 the instruction are already known. And for some machines, register\n\
3533 classes are small for, say, integer registers but not for floating point\n\
3534 registers. For example, the AMD x86-64 architecture requires specific\n\
3535 registers for the legacy x86 integer instructions, but there are many\n\
3536 SSE registers for floating point operations. On such targets, a good\n\
3537 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3538 machine modes but zero for the SSE register classes.\n\
3540 The default version of this hook returns false for any mode. It is always\n\
3541 safe to redefine this hook to return with a nonzero value. But if you\n\
3542 unnecessarily define it, you will reduce the amount of optimizations\n\
3543 that can be performed in some cases. If you do not define this hook\n\
3544 to return a nonzero value when it is required, the compiler will run out\n\
3545 of spill registers and print a fatal error message.",
3546 bool, (machine_mode mode),
3547 hook_bool_mode_false)
3549 /* Register number for a flags register. Only needs to be defined if the
3550 target is constrainted to use post-reload comparison elimination. */
3553 "If the target has a dedicated flags register, and it needs to use the\
3554 post-reload comparison elimination pass, then this value should be set\
3556 unsigned int, INVALID_REGNUM)
3558 /* Compute a (partial) cost for rtx X. Return true if the complete
3559 cost has been computed, and false if subexpressions should be
3560 scanned. In either case, *TOTAL contains the cost result. */
3561 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3562 not necessarily defined at this point. */
3565 "This target hook describes the relative costs of RTL expressions.\n\
3567 The cost may depend on the precise form of the expression, which is\n\
3568 available for examination in @var{x}, and the fact that @var{x} appears\n\
3569 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3570 That is, the hook can assume that there is some rtx @var{y} such\n\
3571 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3572 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3573 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3575 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3576 do not have a mode, the mode in which @var{x} is used.\n\
3578 In implementing this hook, you can use the construct\n\
3579 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3582 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3583 for the cost of the expression. The hook should modify this value as\n\
3584 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3585 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3586 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3588 When optimizing for code size, i.e.@: when @code{speed} is\n\
3589 false, this target hook should be used to estimate the relative\n\
3590 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3592 The hook returns true when all subexpressions of @var{x} have been\n\
3593 processed, and false when @code{rtx_cost} should recurse.",
3594 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3595 hook_bool_rtx_mode_int_int_intp_bool_false)
3597 /* Compute the cost of X, used as an address. Never called with
3598 invalid addresses. */
3601 "This hook computes the cost of an addressing mode that contains\n\
3602 @var{address}. If not defined, the cost is computed from\n\
3603 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3605 For most CISC machines, the default cost is a good approximation of the\n\
3606 true cost of the addressing mode. However, on RISC machines, all\n\
3607 instructions normally have the same length and execution time. Hence\n\
3608 all addresses will have equal costs.\n\
3610 In cases where more than one form of an address is known, the form with\n\
3611 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3612 cost, the one that is the most complex will be used.\n\
3614 For example, suppose an address that is equal to the sum of a register\n\
3615 and a constant is used twice in the same basic block. When this macro\n\
3616 is not defined, the address will be computed in a register and memory\n\
3617 references will be indirect through that register. On machines where\n\
3618 the cost of the addressing mode containing the sum is no higher than\n\
3619 that of a simple indirect reference, this will produce an additional\n\
3620 instruction and possibly require an additional register. Proper\n\
3621 specification of this macro eliminates this overhead for such machines.\n\
3623 This hook is never called with an invalid address.\n\
3625 On machines where an address involving more than one register is as\n\
3626 cheap as an address computation involving only one register, defining\n\
3627 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3628 be live over a region of code where only one would have been if\n\
3629 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3630 should be considered in the definition of this macro. Equivalent costs\n\
3631 should probably only be given to addresses with different numbers of\n\
3632 registers on machines with lots of registers.",
3633 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3634 default_address_cost)
3636 /* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3637 well defined units. */
3639 (max_noce_ifcvt_seq_cost,
3640 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3641 giving the maximum acceptable cost for a sequence generated by the RTL\n\
3642 if-conversion pass when conditional execution is not available.\n\
3643 The RTL if-conversion pass attempts to convert conditional operations\n\
3644 that would require a branch to a series of unconditional operations and\n\
3645 @code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3646 unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3647 RTL if-conversion is cancelled if the cost of the converted sequence\n\
3648 is greater than the value returned by this hook.\n\
3650 @code{e} is the edge between the basic block containing the conditional\n\
3651 branch to the basic block which would be executed if the condition\n\
3654 The default implementation of this hook uses the\n\
3655 @code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3656 and uses a multiple of @code{BRANCH_COST} otherwise.",
3657 unsigned int, (edge e),
3658 default_max_noce_ifcvt_seq_cost)
3660 /* Permit speculative instructions in delay slots during delayed-branch
3663 (no_speculation_in_delay_slots_p,
3664 "This predicate controls the use of the eager delay slot filler to disallow\n\
3665 speculatively executed instructions being placed in delay slots. Targets\n\
3666 such as certain MIPS architectures possess both branches with and without\n\
3667 delay slots. As the eager delay slot filler can decrease performance,\n\
3668 disabling it is beneficial when ordinary branches are available. Use of\n\
3669 delay slot branches filled using the basic filler is often still desirable\n\
3670 as the delay slot can hide a pipeline bubble.", bool, (void),
3671 hook_bool_void_false)
3673 /* Return where to allocate pseudo for a given hard register initial value. */
3675 (allocate_initial_value,
3677 When the initial value of a hard register has been copied in a pseudo\n\
3678 register, it is often not necessary to actually allocate another register\n\
3679 to this pseudo register, because the original hard register or a stack slot\n\
3680 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3681 is called at the start of register allocation once for each hard register\n\
3682 that had its initial value copied by using\n\
3683 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3684 Possible values are @code{NULL_RTX}, if you don't want\n\
3685 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3686 the hard register itself, if it is known not to be clobbered---or a\n\
3688 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3689 it might decide to use another register anyways.\n\
3690 You may use @code{current_function_is_leaf} or \n\
3691 @code{REG_N_SETS} in the hook to determine if the hard\n\
3692 register in question will not be clobbered.\n\
3693 The default value of this hook is @code{NULL}, which disables any special\n\
3695 rtx, (rtx hard_reg), NULL)
3697 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3698 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3701 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3702 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3703 this hook to enhance precision of analysis for @code{unspec} and\n\
3704 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3705 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3707 int, (const_rtx x, unsigned flags),
3708 default_unspec_may_trap_p)
3710 /* Given a register, this hook should return a parallel of registers
3711 to represent where to find the register pieces. Define this hook
3712 if the register and its mode are represented in Dwarf in
3713 non-contiguous locations, or if the register should be
3714 represented in more than one register in Dwarf. Otherwise, this
3715 hook should return NULL_RTX. */
3717 (dwarf_register_span,
3718 "Given a register, this hook should return a parallel of registers to\n\
3719 represent where to find the register pieces. Define this hook if the\n\
3720 register and its mode are represented in Dwarf in non-contiguous\n\
3721 locations, or if the register should be represented in more than one\n\
3722 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3723 If not defined, the default is to return @code{NULL_RTX}.",
3727 /* Given a register return the mode of the corresponding DWARF frame
3730 (dwarf_frame_reg_mode,
3731 "Given a register, this hook should return the mode which the\n\
3732 corresponding Dwarf frame register should have. This is normally\n\
3733 used to return a smaller mode than the raw mode to prevent call\n\
3734 clobbered parts of a register altering the frame register size",
3735 machine_mode, (int regno),
3736 default_dwarf_frame_reg_mode)
3738 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3739 entries not corresponding directly to registers below
3740 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3741 code, given the address of the table. */
3743 (init_dwarf_reg_sizes_extra,
3744 "If some registers are represented in Dwarf-2 unwind information in\n\
3745 multiple pieces, define this hook to fill in information about the\n\
3746 sizes of those pieces in the table used by the unwinder at runtime.\n\
3747 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3748 filling in a single size corresponding to each hard register;\n\
3749 @var{address} is the address of the table.",
3750 void, (tree address),
3753 /* Fetch the fixed register(s) which hold condition codes, for
3754 targets where it makes sense to look for duplicate assignments to
3755 the condition codes. This should return true if there is such a
3756 register, false otherwise. The arguments should be set to the
3757 fixed register numbers. Up to two condition code registers are
3758 supported. If there is only one for this target, the int pointed
3759 at by the second argument should be set to -1. */
3761 (fixed_condition_code_regs,
3762 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3763 register rather than a pseudo-register to hold condition codes, the\n\
3764 regular CSE passes are often not able to identify cases in which the\n\
3765 hard register is set to a common value. Use this hook to enable a\n\
3766 small pass which optimizes such cases. This hook should return true\n\
3767 to enable this pass, and it should set the integers to which its\n\
3768 arguments point to the hard register numbers used for condition codes.\n\
3769 When there is only one such register, as is true on most systems, the\n\
3770 integer pointed to by @var{p2} should be set to\n\
3771 @code{INVALID_REGNUM}.\n\
3773 The default version of this hook returns false.",
3774 bool, (unsigned int *p1, unsigned int *p2),
3775 hook_bool_uintp_uintp_false)
3777 /* If two condition code modes are compatible, return a condition
3778 code mode which is compatible with both, such that a comparison
3779 done in the returned mode will work for both of the original
3780 modes. If the condition code modes are not compatible, return
3783 (cc_modes_compatible,
3784 "On targets which use multiple condition code modes in class\n\
3785 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3786 validly done in more than one mode. On such a system, define this\n\
3787 target hook to take two mode arguments and to return a mode in which\n\
3788 both comparisons may be validly done. If there is no such mode,\n\
3789 return @code{VOIDmode}.\n\
3791 The default version of this hook checks whether the modes are the\n\
3792 same. If they are, it returns that mode. If they are different, it\n\
3793 returns @code{VOIDmode}.",
3794 machine_mode, (machine_mode m1, machine_mode m2),
3795 default_cc_modes_compatible)
3797 /* Do machine-dependent code transformations. Called just before
3798 delayed-branch scheduling. */
3800 (machine_dependent_reorg,
3801 "If non-null, this hook performs a target-specific pass over the\n\
3802 instruction stream. The compiler will run it at all optimization levels,\n\
3803 just before the point at which it normally does delayed-branch scheduling.\n\
3805 The exact purpose of the hook varies from target to target. Some use\n\
3806 it to do transformations that are necessary for correctness, such as\n\
3807 laying out in-function constant pools or avoiding hardware hazards.\n\
3808 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3810 You need not implement the hook if it has nothing to do. The default\n\
3811 definition is null.",
3814 /* Create the __builtin_va_list type. */
3816 (build_builtin_va_list,
3817 "This hook returns a type node for @code{va_list} for the target.\n\
3818 The default version of the hook returns @code{void*}.",
3820 std_build_builtin_va_list)
3822 /* Enumerate the va list variants. */
3825 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3826 to iterate through the target specific builtin types for va_list. The\n\
3827 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3828 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3830 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3831 this macro and are set to the name of the va_list builtin type and its\n\
3833 If the return value of this macro is zero, then there is no more element.\n\
3834 Otherwise the @var{IDX} should be increased for the next call of this\n\
3835 macro to iterate through all types.",
3836 int, (int idx, const char **pname, tree *ptree),
3839 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3842 "This hook returns the va_list type of the calling convention specified by\n\
3844 The default version of this hook returns @code{va_list_type_node}.",
3845 tree, (tree fndecl),
3848 /* Get the __builtin_va_list type dependent on input type. */
3850 (canonical_va_list_type,
3851 "This hook returns the va_list type of the calling convention specified by the\n\
3852 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3855 std_canonical_va_list_type)
3857 /* ??? Documenting this hook requires a GFDL license grant. */
3859 (expand_builtin_va_start,
3860 "Expand the @code{__builtin_va_start} builtin.",
3861 void, (tree valist, rtx nextarg), NULL)
3863 /* Gimplifies a VA_ARG_EXPR. */
3865 (gimplify_va_arg_expr,
3866 "This hook performs target-specific gimplification of\n\
3867 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3868 arguments to @code{va_arg}; the latter two are as in\n\
3869 @code{gimplify.c:gimplify_expr}.",
3870 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3871 std_gimplify_va_arg_expr)
3873 /* Validity-checking routines for PCH files, target-specific.
3874 get_pch_validity returns a pointer to the data to be stored,
3875 and stores the size in its argument. pch_valid_p gets the same
3876 information back and returns NULL if the PCH is valid,
3877 or an error message if not. */
3880 "This hook returns a pointer to the data needed by\n\
3881 @code{TARGET_PCH_VALID_P} and sets\n\
3882 @samp{*@var{sz}} to the size of the data in bytes.",
3883 void *, (size_t *sz),
3884 default_get_pch_validity)
3888 "This hook checks whether the options used to create a PCH file are\n\
3889 compatible with the current settings. It returns @code{NULL}\n\
3890 if so and a suitable error message if not. Error messages will\n\
3891 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3893 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3894 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3895 It's safe to assume that the data was created by the same version of the\n\
3896 compiler, so no format checking is needed.\n\
3898 The default definition of @code{default_pch_valid_p} should be\n\
3899 suitable for most targets.",
3900 const char *, (const void *data, size_t sz),
3901 default_pch_valid_p)
3905 "Called before writing out a PCH file. If the target has some\n\
3906 garbage-collected data that needs to be in a particular state on PCH loads,\n\
3907 it can use this hook to enforce that state. Very few targets need\n\
3908 to do anything here.",
3912 /* If nonnull, this function checks whether a PCH file with the
3913 given set of target flags can be used. It returns NULL if so,
3914 otherwise it returns an error message. */
3916 (check_pch_target_flags,
3917 "If this hook is nonnull, the default implementation of\n\
3918 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
3919 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
3920 @code{target_flags} had when the PCH file was created. The return\n\
3921 value is the same as for @code{TARGET_PCH_VALID_P}.",
3922 const char *, (int pch_flags), NULL)
3924 /* True if the compiler should give an enum type only as many
3925 bytes as it takes to represent the range of possible values of
3928 (default_short_enums,
3929 "This target hook should return true if the compiler should give an\n\
3930 @code{enum} type only as many bytes as it takes to represent the range\n\
3931 of possible values of that type. It should return false if all\n\
3932 @code{enum} types should be allocated like @code{int}.\n\
3934 The default is to return false.",
3936 hook_bool_void_false)
3938 /* This target hook returns an rtx that is used to store the address
3939 of the current frame into the built-in setjmp buffer. */
3941 (builtin_setjmp_frame_value,
3942 "This target hook should return an rtx that is used to store\n\
3943 the address of the current frame into the built in @code{setjmp} buffer.\n\
3944 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
3945 machines. One reason you may need to define this target hook is if\n\
3946 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
3948 default_builtin_setjmp_frame_value)
3950 /* This target hook should manipulate the outputs, inputs, constraints,
3951 and clobbers the port wishes for pre-processing the asm. */
3954 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
3955 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
3956 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
3957 to avoid clobbering a register that is already used by the asm.\n\
3959 It may modify the @var{outputs}, @var{inputs}, and @var{constraints}\n\
3960 as necessary for other pre-processing. In this case the return value is\n\
3961 a sequence of insns to emit after the asm.",
3963 (vec<rtx>& outputs, vec<rtx>& inputs, vec<const char *>& constraints,
3964 vec<rtx>& clobbers, HARD_REG_SET& clobbered_regs),
3967 /* This target hook allows the backend to specify a calling convention
3968 in the debug information. This function actually returns an
3969 enum dwarf_calling_convention, but because of forward declarations
3970 and not wanting to include dwarf2.h everywhere target.h is included
3971 the function is being declared as an int. */
3973 (dwarf_calling_convention,
3974 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
3975 be emitted for each function. Instead of an integer return the enum\n\
3976 value for the @code{DW_CC_} tag.",
3977 int, (const_tree function),
3978 hook_int_const_tree_0)
3980 /* This target hook allows the backend to emit frame-related insns that
3981 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
3982 engine will invoke it on insns of the form
3983 (set (reg) (unspec [...] UNSPEC_INDEX))
3985 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
3986 to let the backend emit the call frame instructions. */
3988 (dwarf_handle_frame_unspec,
3989 "This target hook allows the backend to emit frame-related insns that\n\
3990 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
3991 info engine will invoke it on insns of the form\n\
3993 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
3994 @end smallexample\n\
3997 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
3998 @end smallexample\n\
3999 to let the backend emit the call frame instructions. @var{label} is\n\
4000 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4001 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4002 void, (const char *label, rtx pattern, int index), NULL)
4004 /* ??? Documenting this hook requires a GFDL license grant. */
4006 (stdarg_optimize_hook,
4007 "Perform architecture specific checking of statements gimplified\
4008 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4009 the statement doesn't need to be checked for @code{va_list} references.",
4010 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4012 /* This target hook allows the operating system to override the DECL
4013 that represents the external variable that contains the stack
4014 protection guard variable. The type of this DECL is ptr_type_node. */
4016 (stack_protect_guard,
4017 "This hook returns a @code{DECL} node for the external variable to use\n\
4018 for the stack protection guard. This variable is initialized by the\n\
4019 runtime to some random value and is used to initialize the guard value\n\
4020 that is placed at the top of the local stack frame. The type of this\n\
4021 variable must be @code{ptr_type_node}.\n\
4023 The default version of this hook creates a variable called\n\
4024 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4026 default_stack_protect_guard)
4028 /* This target hook allows the operating system to override the CALL_EXPR
4029 that is invoked when a check vs the guard variable fails. */
4031 (stack_protect_fail,
4032 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4033 stack protect guard variable has been modified. This expression should\n\
4034 involve a call to a @code{noreturn} function.\n\
4036 The default version of this hook invokes a function called\n\
4037 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
4038 normally defined in @file{libgcc2.c}.",
4040 default_external_stack_protect_fail)
4044 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4045 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4046 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4047 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4048 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4049 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4050 loop is only entered from the top.\n\
4052 This hook is only used if @code{doloop_end} is available. The default\n\
4053 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4054 if the loop must be the innermost, and if there are no other restrictions.",
4055 bool, (const widest_int &iterations, const widest_int &iterations_max,
4056 unsigned int loop_depth, bool entered_at_top),
4057 hook_bool_wint_wint_uint_bool_true)
4059 /* Returns NULL if target supports the insn within a doloop block,
4060 otherwise it returns an error message. */
4062 (invalid_within_doloop,
4064 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4065 low-overhead loop, otherwise return a string explaining why doloop\n\
4066 could not be applied.\n\
4068 Many targets use special registers for low-overhead looping. For any\n\
4069 instruction that clobbers these this function should return a string indicating\n\
4070 the reason why the doloop could not be applied.\n\
4071 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4072 loops containing function calls or branch on table instructions.",
4073 const char *, (const rtx_insn *insn),
4074 default_invalid_within_doloop)
4076 /* Returns true for a legitimate combined insn. */
4078 (legitimate_combined_insn,
4079 "Take an instruction in @var{insn} and return @code{false} if the instruction\
4080 is not appropriate as a combination of two or more instructions. The\
4081 default is to accept all instructions.",
4082 bool, (rtx_insn *insn),
4083 hook_bool_rtx_insn_true)
4086 (valid_dllimport_attribute_p,
4087 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
4088 specified. Use this hook if the target needs to add extra validation\
4089 checks to @code{handle_dll_attribute}.",
4090 bool, (const_tree decl),
4091 hook_bool_const_tree_true)
4093 /* If non-zero, align constant anchors in CSE to a multiple of this
4097 "On some architectures it can take multiple instructions to synthesize\n\
4098 a constant. If there is another constant already in a register that\n\
4099 is close enough in value then it is preferable that the new constant\n\
4100 is computed from this register using immediate addition or\n\
4101 subtraction. We accomplish this through CSE. Besides the value of\n\
4102 the constant we also add a lower and an upper constant anchor to the\n\
4103 available expressions. These are then queried when encountering new\n\
4104 constants. The anchors are computed by rounding the constant up and\n\
4105 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4106 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4107 accepted by immediate-add plus one. We currently assume that the\n\
4108 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4109 MIPS, where add-immediate takes a 16-bit signed value,\n\
4110 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4111 is zero, which disables this optimization.",
4112 unsigned HOST_WIDE_INT, 0)
4114 /* Defines, which target-dependent bits (upper 16) are used by port */
4117 "Validate target specific memory model mask bits. When NULL no target specific\n\
4118 memory model bits are allowed.",
4119 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4121 /* Defines an offset bitwise ored into shifted address to get corresponding
4122 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4123 supported by the target. */
4125 (asan_shadow_offset,
4126 "Return the offset bitwise ored into shifted address to get corresponding\n\
4127 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4128 supported by the target.",
4129 unsigned HOST_WIDE_INT, (void),
4132 /* Functions relating to calls - argument passing, returns, etc. */
4133 /* Members of struct call have no special macro prefix. */
4134 HOOK_VECTOR (TARGET_CALLS, calls)
4137 (promote_function_mode,
4138 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4139 function return values. The target hook should return the new mode\n\
4140 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4141 change signedness. This function is called only for scalar @emph{or\n\
4144 @var{for_return} allows to distinguish the promotion of arguments and\n\
4145 return values. If it is @code{1}, a return value is being promoted and\n\
4146 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4147 If it is @code{2}, the returned mode should be that of the register in\n\
4148 which an incoming parameter is copied, or the outgoing result is computed;\n\
4149 then the hook should return the same mode as @code{promote_mode}, though\n\
4150 the signedness may be different.\n\
4152 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4154 The default is to not promote arguments and return values. You can\n\
4155 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4156 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4157 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4158 const_tree funtype, int for_return),
4159 default_promote_function_mode)
4162 (promote_prototypes,
4163 "This target hook returns @code{true} if an argument declared in a\n\
4164 prototype as an integral type smaller than @code{int} should actually be\n\
4165 passed as an @code{int}. In addition to avoiding errors in certain\n\
4166 cases of mismatch, it also makes for better code on certain machines.\n\
4167 The default is to not promote prototypes.",
4168 bool, (const_tree fntype),
4169 hook_bool_const_tree_false)
4173 "This target hook should return the location of the structure value\n\
4174 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4175 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4176 be @code{NULL}, for libcalls. You do not need to define this target\n\
4177 hook if the address is always passed as an ``invisible'' first\n\
4180 On some architectures the place where the structure value address\n\
4181 is found by the called function is not the same place that the\n\
4182 caller put it. This can be due to register windows, or it could\n\
4183 be because the function prologue moves it to a different place.\n\
4184 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4185 the context of the called function, and @code{0} in the context of\n\
4188 If @var{incoming} is nonzero and the address is to be found on the\n\
4189 stack, return a @code{mem} which refers to the frame pointer. If\n\
4190 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4191 structure value address at the beginning of a function. If you need\n\
4192 to emit adjusting code, you should do it at this point.",
4193 rtx, (tree fndecl, int incoming),
4194 hook_rtx_tree_int_null)
4197 (omit_struct_return_reg,
4198 "Normally, when a function returns a structure by memory, the address\n\
4199 is passed as an invisible pointer argument, but the compiler also\n\
4200 arranges to return the address from the function like it would a normal\n\
4201 pointer return value. Define this to true if that behavior is\n\
4202 undesirable on your target.",
4207 "This target hook should return a nonzero value to say to return the\n\
4208 function value in memory, just as large structures are always returned.\n\
4209 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4210 will be the type of the function doing the returning, or @code{NULL} for\n\
4213 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4214 by this function. Also, the option @option{-fpcc-struct-return}\n\
4215 takes effect regardless of this macro. On most systems, it is\n\
4216 possible to leave the hook undefined; this causes a default\n\
4217 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4218 values, and 0 otherwise.\n\
4220 Do not use this hook to indicate that structures and unions should always\n\
4221 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4223 bool, (const_tree type, const_tree fntype),
4224 default_return_in_memory)
4228 "This hook should return true if values of type @var{type} are returned\n\
4229 at the most significant end of a register (in other words, if they are\n\
4230 padded at the least significant end). You can assume that @var{type}\n\
4231 is returned in a register; the caller is required to check this.\n\
4233 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4234 be able to hold the complete return value. For example, if a 1-, 2-\n\
4235 or 3-byte structure is returned at the most significant end of a\n\
4236 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4237 @code{SImode} rtx.",
4238 bool, (const_tree type),
4239 hook_bool_const_tree_false)
4241 /* Return true if a parameter must be passed by reference. TYPE may
4242 be null if this is a libcall. CA may be null if this query is
4243 from __builtin_va_arg. */
4246 "This target hook should return @code{true} if an argument at the\n\
4247 position indicated by @var{cum} should be passed by reference. This\n\
4248 predicate is queried after target independent reasons for being\n\
4249 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
4251 If the hook returns true, a copy of that argument is made in memory and a\n\
4252 pointer to the argument is passed instead of the argument itself.\n\
4253 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4256 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4257 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4260 (expand_builtin_saveregs,
4261 "If defined, this hook produces the machine-specific code for a call to\n\
4262 @code{__builtin_saveregs}. This code will be moved to the very\n\
4263 beginning of the function, before any parameter access are made. The\n\
4264 return value of this function should be an RTX that contains the value\n\
4265 to use as the return of @code{__builtin_saveregs}.",
4267 default_expand_builtin_saveregs)
4269 /* Returns pretend_argument_size. */
4271 (setup_incoming_varargs,
4272 "This target hook offers an alternative to using\n\
4273 @code{__builtin_saveregs} and defining the hook\n\
4274 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4275 register arguments into the stack so that all the arguments appear to\n\
4276 have been passed consecutively on the stack. Once this is done, you can\n\
4277 use the standard implementation of varargs that works for machines that\n\
4278 pass all their arguments on the stack.\n\
4280 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4281 structure, containing the values that are obtained after processing the\n\
4282 named arguments. The arguments @var{mode} and @var{type} describe the\n\
4283 last named argument---its machine mode and its data type as a tree node.\n\
4285 The target hook should do two things: first, push onto the stack all the\n\
4286 argument registers @emph{not} used for the named arguments, and second,\n\
4287 store the size of the data thus pushed into the @code{int}-valued\n\
4288 variable pointed to by @var{pretend_args_size}. The value that you\n\
4289 store here will serve as additional offset for setting up the stack\n\
4292 Because you must generate code to push the anonymous arguments at\n\
4293 compile time without knowing their data types,\n\
4294 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4295 have just a single category of argument register and use it uniformly\n\
4296 for all data types.\n\
4298 If the argument @var{second_time} is nonzero, it means that the\n\
4299 arguments of the function are being analyzed for the second time. This\n\
4300 happens for an inline function, which is not actually compiled until the\n\
4301 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4302 not generate any instructions in this case.",
4303 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4304 int *pretend_args_size, int second_time),
4305 default_setup_incoming_varargs)
4308 (load_bounds_for_arg,
4309 "This hook is used by expand pass to emit insn to load bounds of\n\
4310 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4311 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4312 memory, then bounds are loaded as for regular pointer loaded from\n\
4313 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4314 constant holding number of the target dependent special slot which\n\
4315 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4316 rtx, (rtx slot, rtx arg, rtx slot_no),
4317 default_load_bounds_for_arg)
4320 (store_bounds_for_arg,
4321 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4322 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4323 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4324 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4325 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4326 constant holding number of the target dependent special slot which\n\
4327 should be used to store @var{bounds}.",
4328 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4329 default_store_bounds_for_arg)
4332 (load_returned_bounds,
4333 "This hook is used by expand pass to emit insn to load bounds\n\
4334 returned by function call in @var{slot}. Hook returns RTX holding\n\
4337 default_load_returned_bounds)
4340 (store_returned_bounds,
4341 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4342 returned by function call into @var{slot}.",
4343 void, (rtx slot, rtx bounds),
4344 default_store_returned_bounds)
4347 (setup_incoming_vararg_bounds,
4348 "Use it to store bounds for anonymous register arguments stored\n\
4349 into the stack. Arguments meaning is similar to\n\
4350 @code{TARGET_SETUP_INCOMING_VARARGS}.",
4351 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
4352 int *pretend_args_size, int second_time),
4353 default_setup_incoming_vararg_bounds)
4357 "While generating RTL for a function call, this target hook is invoked once\n\
4358 for each argument passed to the function, either a register returned by\n\
4359 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4360 before the point where argument registers are stored. The type of the\n\
4361 function to be called is also passed as the second argument; it is\n\
4362 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4363 invoked just after the code to copy the return reg has been emitted.\n\
4364 This functionality can be used to perform special setup of call argument\n\
4365 registers if a target needs it.\n\
4366 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4367 passed instead of an argument register.\n\
4368 Most ports do not need to implement anything for this hook.",
4374 "This target hook is invoked while generating RTL for a function call,\n\
4375 just after the point where the return reg is copied into a pseudo. It\n\
4376 signals that all the call argument and return registers for the just\n\
4377 emitted call are now no longer in use.\n\
4378 Most ports do not need to implement anything for this hook.",
4383 (strict_argument_naming,
4384 "Define this hook to return @code{true} if the location where a function\n\
4385 argument is passed depends on whether or not it is a named argument.\n\
4387 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4388 is set for varargs and stdarg functions. If this hook returns\n\
4389 @code{true}, the @var{named} argument is always true for named\n\
4390 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4391 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4392 then all arguments are treated as named. Otherwise, all named arguments\n\
4393 except the last are treated as named.\n\
4395 You need not define this hook if it always returns @code{false}.",
4396 bool, (cumulative_args_t ca),
4397 hook_bool_CUMULATIVE_ARGS_false)
4399 /* Returns true if we should use
4400 targetm.calls.setup_incoming_varargs() and/or
4401 targetm.calls.strict_argument_naming(). */
4403 (pretend_outgoing_varargs_named,
4404 "If you need to conditionally change ABIs so that one works with\n\
4405 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4406 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4407 defined, then define this hook to return @code{true} if\n\
4408 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4409 Otherwise, you should not define this hook.",
4410 bool, (cumulative_args_t ca),
4411 default_pretend_outgoing_varargs_named)
4413 /* Given a complex type T, return true if a parameter of type T
4414 should be passed as two scalars. */
4417 "This hook should return true if parameter of type @var{type} are passed\n\
4418 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4419 arguments into the target's word size. Some ABIs require complex arguments\n\
4420 to be split and treated as their individual components. For example, on\n\
4421 AIX64, complex floats should be passed in a pair of floating point\n\
4422 registers, even though a complex float would fit in one 64-bit floating\n\
4425 The default value of this hook is @code{NULL}, which is treated as always\n\
4427 bool, (const_tree type), NULL)
4429 /* Return true if type T, mode MODE, may not be passed in registers,
4430 but must be passed on the stack. */
4431 /* ??? This predicate should be applied strictly after pass-by-reference.
4432 Need audit to verify that this is the case. */
4434 (must_pass_in_stack,
4435 "This target hook should return @code{true} if we should not pass @var{type}\n\
4436 solely in registers. The file @file{expr.h} defines a\n\
4437 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4439 bool, (machine_mode mode, const_tree type),
4440 must_pass_in_stack_var_size_or_pad)
4442 /* Return true if type TYPE, mode MODE, which is passed by reference,
4443 should have the object copy generated by the callee rather than
4444 the caller. It is never called for TYPE requiring constructors. */
4447 "The function argument described by the parameters to this hook is\n\
4448 known to be passed by reference. The hook should return true if the\n\
4449 function argument should be copied by the callee instead of copied\n\
4452 For any argument for which the hook returns true, if it can be\n\
4453 determined that the argument is not modified, then a copy need\n\
4454 not be generated.\n\
4456 The default version of this hook always returns false.",
4458 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4459 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4461 /* Return zero for arguments passed entirely on the stack or entirely
4462 in registers. If passed in both, return the number of bytes passed
4463 in registers; the balance is therefore passed on the stack. */
4466 "This target hook returns the number of bytes at the beginning of an\n\
4467 argument that must be put in registers. The value must be zero for\n\
4468 arguments that are passed entirely in registers or that are entirely\n\
4469 pushed on the stack.\n\
4471 On some machines, certain arguments must be passed partially in\n\
4472 registers and partially in memory. On these machines, typically the\n\
4473 first few words of arguments are passed in registers, and the rest\n\
4474 on the stack. If a multi-word argument (a @code{double} or a\n\
4475 structure) crosses that boundary, its first few words must be passed\n\
4476 in registers and the rest must be pushed. This macro tells the\n\
4477 compiler when this occurs, and how many bytes should go in registers.\n\
4479 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4480 register to be used by the caller for this argument; likewise\n\
4481 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4482 int, (cumulative_args_t cum, machine_mode mode, tree type, bool named),
4483 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
4485 /* Update the state in CA to advance past an argument in the
4486 argument list. The values MODE, TYPE, and NAMED describe that
4489 (function_arg_advance,
4490 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4491 advance past an argument in the argument list. The values @var{mode},\n\
4492 @var{type} and @var{named} describe that argument. Once this is done,\n\
4493 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4494 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4496 This hook need not do anything if the argument in question was passed\n\
4497 on the stack. The compiler knows how to track the amount of stack space\n\
4498 used for arguments without any special help.",
4500 (cumulative_args_t ca, machine_mode mode, const_tree type, bool named),
4501 default_function_arg_advance)
4503 /* Return zero if the argument described by the state of CA should
4504 be placed on a stack, or a hard register in which to store the
4505 argument. The values MODE, TYPE, and NAMED describe that
4509 "Return an RTX indicating whether a function argument is passed in a\n\
4510 register and if so, which register.\n\
4512 The arguments are @var{ca}, which summarizes all the previous\n\
4513 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
4514 the data type of the argument as a tree node or 0 if that is not known\n\
4515 (which happens for C support library functions); and @var{named},\n\
4516 which is @code{true} for an ordinary argument and @code{false} for\n\
4517 nameless arguments that correspond to @samp{@dots{}} in the called\n\
4518 function's prototype. @var{type} can be an incomplete type if a\n\
4519 syntax error has previously occurred.\n\
4521 The return value is usually either a @code{reg} RTX for the hard\n\
4522 register in which to pass the argument, or zero to pass the argument\n\
4525 The return value can be a @code{const_int} which means argument is\n\
4526 passed in a target specific slot with specified number. Target hooks\n\
4527 should be used to store or load argument in such case. See\n\
4528 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4529 for more information.\n\
4531 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4532 used when an argument is passed in multiple locations. The mode of the\n\
4533 @code{parallel} should be the mode of the entire argument. The\n\
4534 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4535 describes where part of the argument is passed. In each\n\
4536 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4537 register in which to pass this part of the argument, and the mode of the\n\
4538 register RTX indicates how large this part of the argument is. The\n\
4539 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4540 the offset in bytes into the entire argument of where this part starts.\n\
4541 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4542 RTX may have a first operand of zero. This indicates that the entire\n\
4543 argument is also stored on the stack.\n\
4545 The last time this hook is called, it is called with @code{MODE ==\n\
4546 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4547 pattern as operands 2 and 3 respectively.\n\
4549 @cindex @file{stdarg.h} and register arguments\n\
4550 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4551 machine where some arguments are usually passed in registers, is to\n\
4552 cause nameless arguments to be passed on the stack instead. This is\n\
4553 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4554 @var{named} is @code{false}.\n\
4556 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4557 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4558 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4559 in the definition of this macro to determine if this argument is of a\n\
4560 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4561 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4562 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4563 defined, the argument will be computed in the stack and then loaded into\n\
4565 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4567 default_function_arg)
4570 (function_incoming_arg,
4571 "Define this hook if the caller and callee on the target have different\n\
4572 views of where arguments are passed. Also define this hook if there are\n\
4573 functions that are never directly called, but are invoked by the hardware\n\
4574 and which have nonstandard calling conventions.\n\
4576 In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
4577 which the caller passes the value, and\n\
4578 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4579 fashion to tell the function being called where the arguments will\n\
4582 @code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
4583 computation using hard register, which can be forced into a register,\n\
4584 so that it can be used to pass special arguments.\n\
4586 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4587 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4588 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4590 default_function_incoming_arg)
4593 (function_arg_boundary,
4594 "This hook returns the alignment boundary, in bits, of an argument\n\
4595 with the specified mode and type. The default hook returns\n\
4596 @code{PARM_BOUNDARY} for all arguments.",
4597 unsigned int, (machine_mode mode, const_tree type),
4598 default_function_arg_boundary)
4601 (function_arg_round_boundary,
4602 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4603 which is the default value for this hook. You can define this hook to\n\
4604 return a different value if an argument size must be rounded to a larger\n\
4606 unsigned int, (machine_mode mode, const_tree type),
4607 default_function_arg_round_boundary)
4609 /* Return the diagnostic message string if function without a prototype
4610 is not allowed for this 'val' argument; NULL otherwise. */
4612 (invalid_arg_for_unprototyped_fn,
4613 "If defined, this macro returns the diagnostic message when it is\n\
4614 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4615 with prototype @var{typelist}.",
4616 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4617 hook_invalid_arg_for_unprototyped_fn)
4619 /* Return an rtx for the return value location of the function
4620 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4624 Define this to return an RTX representing the place where a function\n\
4625 returns or receives a value of data type @var{ret_type}, a tree node\n\
4626 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4627 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4628 function being called. If @var{outgoing} is false, the hook should\n\
4629 compute the register in which the caller will see the return value.\n\
4630 Otherwise, the hook should return an RTX representing the place where\n\
4631 a function returns a value.\n\
4633 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4634 (Actually, on most machines, scalar values are returned in the same\n\
4635 place regardless of mode.) The value of the expression is usually a\n\
4636 @code{reg} RTX for the hard register where the return value is stored.\n\
4637 The value can also be a @code{parallel} RTX, if the return value is in\n\
4638 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4639 @code{parallel} form. Note that the callee will populate every\n\
4640 location specified in the @code{parallel}, but if the first element of\n\
4641 the @code{parallel} contains the whole return value, callers will use\n\
4642 that element as the canonical location and ignore the others. The m68k\n\
4643 port uses this type of @code{parallel} to return pointers in both\n\
4644 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
4646 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4647 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4648 @var{valtype} is a scalar type.\n\
4650 If the precise function being called is known, @var{func} is a tree\n\
4651 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4652 pointer. This makes it possible to use a different value-returning\n\
4653 convention for specific functions when all their calls are\n\
4656 Some target machines have ``register windows'' so that the register in\n\
4657 which a function returns its value is not the same as the one in which\n\
4658 the caller sees the value. For such machines, you should return\n\
4659 different RTX depending on @var{outgoing}.\n\
4661 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4662 aggregate data types, because these are returned in another way. See\n\
4663 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4664 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4665 default_function_value)
4667 /* Return the rtx for bounds of returned pointer. */
4669 (chkp_function_value_bounds,
4670 "Define this to return an RTX representing the place where a function\n\
4671 returns bounds for returned pointers. Arguments meaning is similar to\n\
4672 @code{TARGET_FUNCTION_VALUE}.",
4673 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4674 default_chkp_function_value_bounds)
4676 /* Return the rtx for the result of a libcall of mode MODE,
4677 calling the function FN_NAME. */
4680 "Define this hook if the back-end needs to know the name of the libcall\n\
4681 function in order to determine where the result should be returned.\n\
4683 The mode of the result is given by @var{mode} and the name of the called\n\
4684 library function is given by @var{fun}. The hook should return an RTX\n\
4685 representing the place where the library function result will be returned.\n\
4687 If this hook is not defined, then LIBCALL_VALUE will be used.",
4688 rtx, (machine_mode mode, const_rtx fun),
4689 default_libcall_value)
4691 /* Return true if REGNO is a possible register number for
4692 a function value as seen by the caller. */
4694 (function_value_regno_p,
4695 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4696 register in which the values of called function may come back.\n\
4698 A register whose use for returning values is limited to serving as the\n\
4699 second of a pair (for a value of type @code{double}, say) need not be\n\
4700 recognized by this target hook.\n\
4702 If the machine has register windows, so that the caller and the called\n\
4703 function use different registers for the return value, this target hook\n\
4704 should recognize only the caller's register numbers.\n\
4706 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4707 bool, (const unsigned int regno),
4708 default_function_value_regno_p)
4710 /* ??? Documenting this hook requires a GFDL license grant. */
4712 (internal_arg_pointer,
4713 "Return an rtx for the argument pointer incoming to the\
4716 default_internal_arg_pointer)
4718 /* Update the current function stack boundary if needed. */
4720 (update_stack_boundary,
4721 "Define this macro to update the current function stack boundary if\n\
4725 /* Handle stack alignment and return an rtx for Dynamic Realign
4726 Argument Pointer if necessary. */
4729 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4730 different argument pointer register is needed to access the function's\n\
4731 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4735 /* Return true if all function parameters should be spilled to the
4738 (allocate_stack_slots_for_args,
4739 "When optimization is disabled, this hook indicates whether or not\n\
4740 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4741 stacks slots for arguments when not optimizing in order to make\n\
4742 debugging easier. However, when a function is declared with\n\
4743 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4744 cannot safely move arguments from the registers in which they are passed\n\
4745 to the stack. Therefore, this hook should return true in general, but\n\
4746 false for naked functions. The default implementation always returns true.",
4748 hook_bool_void_true)
4750 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
4751 is true, then it should be for the callee; otherwise for the caller. */
4754 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4755 targets that may use different static chain locations for different\n\
4756 nested functions. This may be required if the target has function\n\
4757 attributes that affect the calling conventions of the function and\n\
4758 those calling conventions use different static chain locations.\n\
4760 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4762 If the static chain is passed in memory, this hook should be used to\n\
4763 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4764 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4765 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4766 will be at an offset from the frame pointer.\n\
4767 @findex stack_pointer_rtx\n\
4768 @findex frame_pointer_rtx\n\
4769 @findex arg_pointer_rtx\n\
4770 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4771 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4772 to refer to those items.",
4773 rtx, (const_tree fndecl_or_type, bool incoming_p),
4774 default_static_chain)
4776 /* Fill in the trampoline at MEM with a call to FNDECL and a
4777 static chain value of CHAIN. */
4780 "This hook is called to initialize a trampoline.\n\
4781 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4782 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4783 RTX for the static chain value that should be passed to the function\n\
4784 when it is called.\n\
4786 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4787 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4788 from the memory block returned by @code{assemble_trampoline_template}.\n\
4789 Note that the block move need only cover the constant parts of the\n\
4790 trampoline. If the target isolates the variable parts of the trampoline\n\
4791 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4793 If the target requires any other actions, such as flushing caches or\n\
4794 enabling stack execution, these actions should be performed after\n\
4795 initializing the trampoline proper.",
4796 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4797 default_trampoline_init)
4799 /* Adjust the address of the trampoline in a target-specific way. */
4801 (trampoline_adjust_address,
4802 "This hook should perform any machine-specific adjustment in\n\
4803 the address of the trampoline. Its argument contains the address of the\n\
4804 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4805 the address to be used for a function call should be different from the\n\
4806 address at which the template was stored, the different address should\n\
4807 be returned; otherwise @var{addr} should be returned unchanged.\n\
4808 If this hook is not defined, @var{addr} will be used for function calls.",
4809 rtx, (rtx addr), NULL)
4812 (custom_function_descriptors,
4813 "This hook should be defined to a power of 2 if the target will benefit\n\
4814 from the use of custom descriptors for nested functions instead of the\n\
4815 standard trampolines. Such descriptors are created at run time on the\n\
4816 stack and made up of data only, but they are non-standard so the generated\n\
4817 code must be prepared to deal with them. This hook should be defined to 0\n\
4818 if the target uses function descriptors for its standard calling sequence,\n\
4819 like for example HP-PA or IA-64. Using descriptors for nested functions\n\
4820 eliminates the need for trampolines that reside on the stack and require\n\
4821 it to be made executable.\n\
4823 The value of the macro is used to parameterize the run-time identification\n\
4824 scheme implemented to distinguish descriptors from function addresses: it\n\
4825 gives the number of bytes by which their address is misaligned compared\n\
4826 with function addresses. The value of 1 will generally work, unless it is\n\
4827 already reserved by the target for another purpose, like for example on ARM.",\
4830 /* Return the number of bytes of its own arguments that a function
4831 pops on returning, or 0 if the function pops no arguments and the
4832 caller must therefore pop them all after the function returns. */
4833 /* ??? tm.texi has no types for the parameters. */
4836 "This target hook returns the number of bytes of its own arguments that\n\
4837 a function pops on returning, or 0 if the function pops no arguments\n\
4838 and the caller must therefore pop them all after the function returns.\n\
4840 @var{fundecl} is a C variable whose value is a tree node that describes\n\
4841 the function in question. Normally it is a node of type\n\
4842 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
4843 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4845 @var{funtype} is a C variable whose value is a tree node that\n\
4846 describes the function in question. Normally it is a node of type\n\
4847 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
4848 From this it is possible to obtain the data types of the value and\n\
4849 arguments (if known).\n\
4851 When a call to a library function is being considered, @var{fundecl}\n\
4852 will contain an identifier node for the library function. Thus, if\n\
4853 you need to distinguish among various library functions, you can do so\n\
4854 by their names. Note that ``library function'' in this context means\n\
4855 a function used to perform arithmetic, whose name is known specially\n\
4856 in the compiler and was not mentioned in the C code being compiled.\n\
4858 @var{size} is the number of bytes of arguments passed on the\n\
4859 stack. If a variable number of bytes is passed, it is zero, and\n\
4860 argument popping will always be the responsibility of the calling function.\n\
4862 On the VAX, all functions always pop their arguments, so the definition\n\
4863 of this macro is @var{size}. On the 68000, using the standard\n\
4864 calling convention, no functions pop their arguments, so the value of\n\
4865 the macro is always 0 in this case. But an alternative calling\n\
4866 convention is available in which functions that take a fixed number of\n\
4867 arguments pop them but other functions (such as @code{printf}) pop\n\
4868 nothing (the caller pops all). When this convention is in use,\n\
4869 @var{funtype} is examined to determine whether a function takes a fixed\n\
4870 number of arguments.",
4871 int, (tree fundecl, tree funtype, int size),
4872 default_return_pops_args)
4874 /* Return a mode wide enough to copy any function value that might be
4877 (get_raw_result_mode,
4878 "This target hook returns the mode to be used when accessing raw return\
4879 registers in @code{__builtin_return}. Define this macro if the value\
4880 in @var{reg_raw_mode} is not correct.",
4881 machine_mode, (int regno),
4882 default_get_reg_raw_mode)
4884 /* Return a mode wide enough to copy any argument value that might be
4888 "This target hook returns the mode to be used when accessing raw argument\
4889 registers in @code{__builtin_apply_args}. Define this macro if the value\
4890 in @var{reg_raw_mode} is not correct.",
4891 machine_mode, (int regno),
4892 default_get_reg_raw_mode)
4894 HOOK_VECTOR_END (calls)
4897 (use_pseudo_pic_reg,
4898 "This hook should return 1 in case pseudo register should be created\n\
4899 for pic_offset_table_rtx during function expand.",
4901 hook_bool_void_false)
4905 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
4906 This hook is called at the start of register allocation.",
4910 /* Return the diagnostic message string if conversion from FROMTYPE
4911 to TOTYPE is not allowed, NULL otherwise. */
4913 (invalid_conversion,
4914 "If defined, this macro returns the diagnostic message when it is\n\
4915 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
4916 if validity should be determined by the front end.",
4917 const char *, (const_tree fromtype, const_tree totype),
4918 hook_constcharptr_const_tree_const_tree_null)
4920 /* Return the diagnostic message string if the unary operation OP is
4921 not permitted on TYPE, NULL otherwise. */
4924 "If defined, this macro returns the diagnostic message when it is\n\
4925 invalid to apply operation @var{op} (where unary plus is denoted by\n\
4926 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
4927 if validity should be determined by the front end.",
4928 const char *, (int op, const_tree type),
4929 hook_constcharptr_int_const_tree_null)
4931 /* Return the diagnostic message string if the binary operation OP
4932 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
4935 "If defined, this macro returns the diagnostic message when it is\n\
4936 invalid to apply operation @var{op} to operands of types @var{type1}\n\
4937 and @var{type2}, or @code{NULL} if validity should be determined by\n\
4939 const char *, (int op, const_tree type1, const_tree type2),
4940 hook_constcharptr_int_const_tree_const_tree_null)
4942 /* If values of TYPE are promoted to some other type when used in
4943 expressions (analogous to the integer promotions), return that type,
4944 or NULL_TREE otherwise. */
4947 "If defined, this target hook returns the type to which values of\n\
4948 @var{type} should be promoted when they appear in expressions,\n\
4949 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
4950 front end's normal promotion rules. This hook is useful when there are\n\
4951 target-specific types with special promotion rules.\n\
4952 This is currently used only by the C and C++ front ends.",
4953 tree, (const_tree type),
4954 hook_tree_const_tree_null)
4956 /* Convert EXPR to TYPE, if target-specific types with special conversion
4957 rules are involved. Return the converted expression, or NULL to apply
4958 the standard conversion rules. */
4961 "If defined, this hook returns the result of converting @var{expr} to\n\
4962 @var{type}. It should return the converted expression,\n\
4963 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
4964 This hook is useful when there are target-specific types with special\n\
4965 conversion rules.\n\
4966 This is currently used only by the C and C++ front ends.",
4967 tree, (tree type, tree expr),
4968 hook_tree_tree_tree_null)
4970 /* Change pseudo allocno class calculated by IRA. */
4972 (ira_change_pseudo_allocno_class,
4973 "A target hook which can change allocno class for given pseudo from\n\
4974 allocno and best class calculated by IRA.\n\
4976 The default version of this target hook always returns given class.",
4977 reg_class_t, (int, reg_class_t, reg_class_t),
4978 default_ira_change_pseudo_allocno_class)
4980 /* Return true if we use LRA instead of reload. */
4983 "A target hook which returns true if we use LRA instead of reload pass.\
4985 The default version of this target hook returns true. New ports\
4986 should use LRA, and existing ports are encouraged to convert.",
4990 /* Return register priority of given hard regno for the current target. */
4993 "A target hook which returns the register priority number to which the\
4994 register @var{hard_regno} belongs to. The bigger the number, the\
4995 more preferable the hard register usage (when all other conditions are\
4996 the same). This hook can be used to prefer some hard register over\
4997 others in LRA. For example, some x86-64 register usage needs\
4998 additional prefix which makes instructions longer. The hook can\
4999 return lower priority number for such registers make them less favorable\
5000 and as result making the generated code smaller.\
5002 The default version of this target hook returns always zero.",
5004 default_register_priority)
5006 /* Return true if we need register usage leveling. */
5008 (register_usage_leveling_p,
5009 "A target hook which returns true if we need register usage leveling.\
5010 That means if a few hard registers are equally good for the\
5011 assignment, we choose the least used hard register. The register\
5012 usage leveling may be profitable for some targets. Don't use the\
5013 usage leveling for targets with conditional execution or targets\
5014 with big register files as it hurts if-conversion and cross-jumping\
5017 The default version of this target hook returns always false.",
5019 default_register_usage_leveling_p)
5021 /* Return true if maximal address displacement can be different. */
5023 (different_addr_displacement_p,
5024 "A target hook which returns true if an address with the same structure\
5025 can have different maximal legitimate displacement. For example, the\
5026 displacement can depend on memory mode or on operand combinations in\
5029 The default version of this target hook returns always false.",
5031 default_different_addr_displacement_p)
5033 /* Determine class for spilling pseudos of given mode into registers
5034 instead of memory. */
5037 "This hook defines a class of registers which could be used for spilling\
5038 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
5039 should be used. Not defining this hook is equivalent to returning\
5040 @code{NO_REGS} for all inputs.",
5041 reg_class_t, (reg_class_t, machine_mode),
5044 /* Determine an additional allocno class. */
5046 (additional_allocno_class_p,
5047 "This hook should return @code{true} if given class of registers should\
5048 be an allocno class in any way. Usually RA uses only one register\
5049 class from all classes containing the same register set. In some\
5050 complicated cases, you need to have two or more such classes as\
5051 allocno ones for RA correct work. Not defining this hook is\
5052 equivalent to returning @code{false} for all inputs.",
5053 bool, (reg_class_t),
5054 hook_bool_reg_class_t_false)
5058 "This hook defines the machine mode to use for the boolean result of\
5059 conditional store patterns. The ICODE argument is the instruction code\
5060 for the cstore being performed. Not definiting this hook is the same\
5061 as accepting the mode encoded into operand 0 of the cstore expander\
5063 machine_mode, (enum insn_code icode),
5064 default_cstore_mode)
5066 /* This target hook allows the backend to compute the register pressure
5069 (compute_pressure_classes,
5070 "A target hook which lets a backend compute the set of pressure classes to\
5071 be used by those optimization passes which take register pressure into\
5072 account, as opposed to letting IRA compute them. It returns the number of\
5073 register classes stored in the array @var{pressure_classes}.",
5074 int, (enum reg_class *pressure_classes), NULL)
5076 /* True if a structure, union or array with MODE containing FIELD should
5077 be accessed using BLKmode. */
5079 (member_type_forces_blk,
5080 "Return true if a structure, union or array containing @var{field} should\n\
5081 be accessed using @code{BLKMODE}.\n\
5083 If @var{field} is the only field in the structure, @var{mode} is its\n\
5084 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5085 case where structures of one field would require the structure's mode to\n\
5086 retain the field's mode.\n\
5088 Normally, this is not needed.",
5089 bool, (const_tree field, machine_mode mode),
5090 default_member_type_forces_blk)
5092 /* See tree-ssa-math-opts.c:divmod_candidate_p for conditions
5093 that gate the divod transform. */
5095 (expand_divmod_libfunc,
5096 "Define this hook for enabling divmod transform if the port does not have\n\
5097 hardware divmod insn but defines target-specific divmod libfuncs.",
5098 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5101 /* Return the class for a secondary reload, and fill in extra information. */
5104 "Many machines have some registers that cannot be copied directly to or\n\
5105 from memory or even from other types of registers. An example is the\n\
5106 @samp{MQ} register, which on most machines, can only be copied to or\n\
5107 from general registers, but not memory. Below, we shall be using the\n\
5108 term 'intermediate register' when a move operation cannot be performed\n\
5109 directly, but has to be done by copying the source into the intermediate\n\
5110 register first, and then copying the intermediate register to the\n\
5111 destination. An intermediate register always has the same mode as\n\
5112 source and destination. Since it holds the actual value being copied,\n\
5113 reload might apply optimizations to re-use an intermediate register\n\
5114 and eliding the copy from the source when it can determine that the\n\
5115 intermediate register still holds the required value.\n\
5117 Another kind of secondary reload is required on some machines which\n\
5118 allow copying all registers to and from memory, but require a scratch\n\
5119 register for stores to some memory locations (e.g., those with symbolic\n\
5120 address on the RT, and those with certain symbolic address on the SPARC\n\
5121 when compiling PIC)@. Scratch registers need not have the same mode\n\
5122 as the value being copied, and usually hold a different value than\n\
5123 that being copied. Special patterns in the md file are needed to\n\
5124 describe how the copy is performed with the help of the scratch register;\n\
5125 these patterns also describe the number, register class(es) and mode(s)\n\
5126 of the scratch register(s).\n\
5128 In some cases, both an intermediate and a scratch register are required.\n\
5130 For input reloads, this target hook is called with nonzero @var{in_p},\n\
5131 and @var{x} is an rtx that needs to be copied to a register of class\n\
5132 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5133 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5134 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5136 If copying a register of @var{reload_class} from/to @var{x} requires\n\
5137 an intermediate register, the hook @code{secondary_reload} should\n\
5138 return the register class required for this intermediate register.\n\
5139 If no intermediate register is required, it should return NO_REGS.\n\
5140 If more than one intermediate register is required, describe the one\n\
5141 that is closest in the copy chain to the reload register.\n\
5143 If scratch registers are needed, you also have to describe how to\n\
5144 perform the copy from/to the reload register to/from this\n\
5145 closest intermediate register. Or if no intermediate register is\n\
5146 required, but still a scratch register is needed, describe the\n\
5147 copy from/to the reload register to/from the reload operand @var{x}.\n\
5149 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5150 in the md file which performs the move. Operands 0 and 1 are the output\n\
5151 and input of this copy, respectively. Operands from operand 2 onward are\n\
5152 for scratch operands. These scratch operands must have a mode, and a\n\
5153 single-register-class\n\
5154 @c [later: or memory]\n\
5155 output constraint.\n\
5157 When an intermediate register is used, the @code{secondary_reload}\n\
5158 hook will be called again to determine how to copy the intermediate\n\
5159 register to/from the reload operand @var{x}, so your hook must also\n\
5160 have code to handle the register class of the intermediate operand.\n\
5162 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5163 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5164 @c and match the constraints of input and output to determine the required\n\
5165 @c alternative. A restriction would be that constraints used to match\n\
5166 @c against reloads registers would have to be written as register class\n\
5167 @c constraints, or we need a new target macro / hook that tells us if an\n\
5168 @c arbitrary constraint can match an unknown register of a given class.\n\
5169 @c Such a macro / hook would also be useful in other places.]\n\
5172 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5173 pseudo-register, which could either be in a hard register or in memory.\n\
5174 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5175 in memory and the hard register number if it is in a register.\n\
5177 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5178 currently not supported. For the time being, you will have to continue\n\
5179 to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5181 @code{copy_cost} also uses this target hook to find out how values are\n\
5182 copied. If you want it to include some extra cost for the need to allocate\n\
5183 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5184 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5185 of the individual moves due to expected fortuitous scheduling and/or special\n\
5186 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5188 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5189 secondary_reload_info *sri),
5190 default_secondary_reload)
5192 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5193 return the class of reg to actually use. */
5195 (preferred_reload_class,
5196 "A target hook that places additional restrictions on the register class\n\
5197 to use when it is necessary to copy value @var{x} into a register in class\n\
5198 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5199 another, smaller class.\n\
5201 The default version of this hook always returns value of @code{rclass} argument.\n\
5203 Sometimes returning a more restrictive class makes better code. For\n\
5204 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5205 for a @samp{moveq} instruction, the value of this macro is always\n\
5206 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5207 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5209 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5210 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5211 loaded into some register class. By returning @code{NO_REGS} you can\n\
5212 force @var{x} into a memory location. For example, rs6000 can load\n\
5213 immediate values into general-purpose registers, but does not have an\n\
5214 instruction for loading an immediate value into a floating-point\n\
5215 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5216 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5217 into any kind of register, code generation will be better if\n\
5218 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5219 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5221 If an insn has pseudos in it after register allocation, reload will go\n\
5222 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5223 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5224 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5225 this feature to discourage usage of 387 registers when math is done in\n\
5226 the SSE registers (and vice versa).",
5228 (rtx x, reg_class_t rclass),
5229 default_preferred_reload_class)
5231 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5234 (preferred_output_reload_class,
5235 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5238 The default version of this hook always returns value of @code{rclass}\n\
5241 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5242 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5244 (rtx x, reg_class_t rclass),
5245 default_preferred_output_reload_class)
5248 (class_likely_spilled_p,
5249 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5250 to registers of class @var{rclass} would likely be spilled because\n\
5251 registers of @var{rclass} are needed for spill registers.\n\
5253 The default version of this target hook returns @code{true} if @var{rclass}\n\
5254 has exactly one register and @code{false} otherwise. On most machines, this\n\
5255 default should be used. For generally register-starved machines, such as\n\
5256 i386, or machines with right register constraints, such as SH, this hook\n\
5257 can be used to avoid excessive spilling.\n\
5259 This hook is also used by some of the global intra-procedural code\n\
5260 transformations to throtle code motion, to avoid increasing register\n\
5262 bool, (reg_class_t rclass),
5263 default_class_likely_spilled_p)
5265 /* Return the maximum number of consecutive registers
5266 needed to represent mode MODE in a register of class RCLASS. */
5269 "A target hook returns the maximum number of consecutive registers\n\
5270 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5272 This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact,\n\
5273 the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5274 @var{mode})} target hook should be the maximum value of\n\
5275 @code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5276 values in the class @var{rclass}.\n\
5278 This target hook helps control the handling of multiple-word values\n\
5279 in the reload pass.\n\
5281 The default version of this target hook returns the size of @var{mode}\n\
5283 unsigned char, (reg_class_t rclass, machine_mode mode),
5284 default_class_max_nregs)
5287 (preferred_rename_class,
5288 "A target hook that places additional preference on the register\
5289 class to use when it is necessary to rename a register in class\
5290 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5291 preferred register class is found or hook @code{preferred_rename_class}\
5292 is not implemented.\
5293 Sometimes returning a more restrictive class makes better code. For\
5294 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5295 smaller than instructions using @code{GENERIC_REGS}. By returning\
5296 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5298 reg_class_t, (reg_class_t rclass),
5299 default_preferred_rename_class)
5301 /* This target hook allows the backend to avoid unsafe substitution
5302 during register allocation. */
5304 (cannot_substitute_mem_equiv_p,
5305 "A target hook which returns @code{true} if @var{subst} can't\n\
5306 substitute safely pseudos with equivalent memory values during\n\
5307 register allocation.\n\
5308 The default version of this target hook returns @code{false}.\n\
5309 On most machines, this default should be used. For generally\n\
5310 machines with non orthogonal register usage for addressing, such\n\
5311 as SH, this hook can be used to avoid excessive spilling.",
5313 hook_bool_rtx_false)
5315 /* This target hook allows the backend to legitimize base plus
5316 displacement addressing. */
5318 (legitimize_address_displacement,
5319 "A target hook which returns @code{true} if *@var{disp} is\n\
5320 legitimezed to valid address displacement with subtracting *@var{offset}\n\
5321 at memory mode @var{mode}.\n\
5322 The default version of this target hook returns @code{false}.\n\
5323 This hook will benefit machines with limited base plus displacement\n\
5325 bool, (rtx *disp, rtx *offset, machine_mode mode),
5326 default_legitimize_address_displacement)
5328 /* This target hook allows the backend to perform additional
5329 processing while initializing for variable expansion. */
5331 (expand_to_rtl_hook,
5332 "This hook is called just before expansion into rtl, allowing the target\n\
5333 to perform additional initializations or analysis before the expansion.\n\
5334 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5335 for use in copying SDmode values between memory and floating point\n\
5336 registers whenever the function being expanded has any SDmode\n\
5341 /* This target hook allows the backend to perform additional
5342 instantiations on rtx that are not actually in insns yet,
5343 but will be later. */
5346 "This hook allows the backend to perform additional instantiations on rtl\n\
5347 that are not actually in any insns yet, but will be later.",
5351 /* Return true if is OK to use a hard register REGNO as scratch register
5354 (hard_regno_scratch_ok,
5355 "This target hook should return @code{true} if it is OK to use a hard register\n\
5356 @var{regno} as scratch reg in peephole2.\n\
5358 One common use of this macro is to prevent using of a register that\n\
5359 is not saved by a prologue in an interrupt handler.\n\
5361 The default version of this hook always returns @code{true}.",
5362 bool, (unsigned int regno),
5363 default_hard_regno_scratch_ok)
5365 /* Return the smallest number of different values for which it is best to
5366 use a jump-table instead of a tree of conditional branches. */
5368 (case_values_threshold,
5369 "This function return the smallest number of different values for which it\n\
5370 is best to use a jump-table instead of a tree of conditional branches.\n\
5371 The default is four for machines with a @code{casesi} instruction and\n\
5372 five otherwise. This is best for most machines.",
5373 unsigned int, (void),
5374 default_case_values_threshold)
5376 /* Return true if a function must have and use a frame pointer. */
5378 (frame_pointer_required,
5379 "This target hook should return @code{true} if a function must have and use\n\
5380 a frame pointer. This target hook is called in the reload pass. If its return\n\
5381 value is @code{true} the function will have a frame pointer.\n\
5383 This target hook can in principle examine the current function and decide\n\
5384 according to the facts, but on most machines the constant @code{false} or the\n\
5385 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
5386 to be generated with no frame pointer, and doing so saves some time or space.\n\
5387 Use @code{true} when there is no possible advantage to avoiding a frame\n\
5390 In certain cases, the compiler does not know how to produce valid code\n\
5391 without a frame pointer. The compiler recognizes those cases and\n\
5392 automatically gives the function a frame pointer regardless of what\n\
5393 @code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
5396 In a function that does not require a frame pointer, the frame pointer\n\
5397 register can be allocated for ordinary usage, unless you mark it as a\n\
5398 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
5400 Default return value is @code{false}.",
5402 hook_bool_void_false)
5404 /* Returns true if the compiler is allowed to try to replace register number
5405 from-reg with register number to-reg. */
5408 "This target hook should return @code{true} if the compiler is allowed to\n\
5409 try to replace register number @var{from_reg} with register number\n\
5410 @var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
5411 cases preventing register elimination are things that the compiler already\n\
5414 Default return value is @code{true}.",
5415 bool, (const int from_reg, const int to_reg),
5416 hook_bool_const_int_const_int_true)
5418 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
5419 reg_names, and reg_class_contents to account of the vagaries of the
5422 (conditional_register_usage,
5423 "This hook may conditionally modify five variables\n\
5424 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
5425 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
5426 any dependence of these register sets on target flags. The first three\n\
5427 of these are of type @code{char []} (interpreted as boolean vectors).\n\
5428 @code{global_regs} is a @code{const char *[]}, and\n\
5429 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
5430 called, @code{fixed_regs}, @code{call_used_regs},\n\
5431 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
5432 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
5433 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
5434 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
5435 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
5436 command options have been applied.\n\
5438 @cindex disabling certain registers\n\
5439 @cindex controlling register usage\n\
5440 If the usage of an entire class of registers depends on the target\n\
5441 flags, you may indicate this to GCC by using this macro to modify\n\
5442 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
5443 registers in the classes which should not be used by GCC@. Also make\n\
5444 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
5445 that shouldn't be used.\n\
5447 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
5448 of the insn patterns whose constraints permit this class are\n\
5449 controlled by target switches, then GCC will automatically avoid using\n\
5450 these registers when the target switches are opposed to them.)",
5454 /* Functions specific to the C family of frontends. */
5456 #define HOOK_PREFIX "TARGET_C_"
5457 HOOK_VECTOR (TARGET_C, c)
5459 /* ??? Documenting this hook requires a GFDL license grant. */
5462 "Return machine mode for non-standard constant literal suffix @var{c},\
5463 or VOIDmode if non-standard suffixes are unsupported.",
5464 machine_mode, (char c),
5465 default_mode_for_suffix)
5469 "Return a value, with the same meaning as the C99 macro\
5470 @code{FLT_EVAL_METHOD} that describes which excess precision should be\
5471 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\
5472 @code{EXCESS_PRECISION_TYPE_FAST}, or\
5473 @code{EXCESS_PRECISION_TYPE_STANDARD}. For\
5474 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\
5475 precision and range operations will be implictly evaluated in regardless\
5476 of the excess precision explicitly added. For\
5477 @code{EXCESS_PRECISION_TYPE_STANDARD} and\
5478 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\
5479 explicit excess precision that should be added depending on the\
5480 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\
5481 Note that unpredictable explicit excess precision does not make sense,\
5482 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\
5483 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or\
5484 @code{EXCESS_PRECISION_TYPE_FAST}.",
5485 enum flt_eval_method, (enum excess_precision_type type),
5486 default_excess_precision)
5490 /* Functions specific to the C++ frontend. */
5492 #define HOOK_PREFIX "TARGET_CXX_"
5493 HOOK_VECTOR (TARGET_CXX, cxx)
5495 /* Return the integer type used for guard variables. */
5498 "Define this hook to override the integer type used for guard variables.\n\
5499 These are used to implement one-time construction of static objects. The\n\
5500 default is long_long_integer_type_node.",
5502 default_cxx_guard_type)
5504 /* Return true if only the low bit of the guard should be tested. */
5507 "This hook determines how guard variables are used. It should return\n\
5508 @code{false} (the default) if the first byte should be used. A return value of\n\
5509 @code{true} indicates that only the least significant bit should be used.",
5511 hook_bool_void_false)
5513 /* Returns the size of the array cookie for an array of type. */
5516 "This hook returns the size of the cookie to use when allocating an array\n\
5517 whose elements have the indicated @var{type}. Assumes that it is already\n\
5518 known that a cookie is needed. The default is\n\
5519 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
5520 IA64/Generic C++ ABI@.",
5522 default_cxx_get_cookie_size)
5524 /* Returns true if the element size should be stored in the array cookie. */
5527 "This hook should return @code{true} if the element size should be stored in\n\
5528 array cookies. The default is to return @code{false}.",
5530 hook_bool_void_false)
5532 /* Allows backends to perform additional processing when
5533 deciding if a class should be exported or imported. */
5535 (import_export_class,
5536 "If defined by a backend this hook allows the decision made to export\n\
5537 class @var{type} to be overruled. Upon entry @var{import_export}\n\
5538 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
5539 to be imported and 0 otherwise. This function should return the\n\
5540 modified value and perform any other actions necessary to support the\n\
5541 backend's targeted operating system.",
5542 int, (tree type, int import_export), NULL)
5544 /* Returns true if constructors and destructors return "this". */
5546 (cdtor_returns_this,
5547 "This hook should return @code{true} if constructors and destructors return\n\
5548 the address of the object created/destroyed. The default is to return\n\
5551 hook_bool_void_false)
5553 /* Returns true if the key method for a class can be an inline
5554 function, so long as it is not declared inline in the class
5555 itself. Returning true is the behavior required by the Itanium C++ ABI. */
5557 (key_method_may_be_inline,
5558 "This hook returns true if the key method for a class (i.e., the method\n\
5559 which, if defined in the current translation unit, causes the virtual\n\
5560 table to be emitted) may be an inline function. Under the standard\n\
5561 Itanium C++ ABI the key method may be an inline function so long as\n\
5562 the function is not declared inline in the class definition. Under\n\
5563 some variants of the ABI, an inline function can never be the key\n\
5564 method. The default is to return @code{true}.",
5566 hook_bool_void_true)
5569 (determine_class_data_visibility,
5570 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
5571 or other similar implicit class data object that will be emitted with\
5572 external linkage in this translation unit. No ELF visibility has been\
5573 explicitly specified. If the target needs to specify a visibility\
5574 other than that of the containing class, use this hook to set\
5575 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
5579 /* Returns true (the default) if virtual tables and other
5580 similar implicit class data objects are always COMDAT if they
5581 have external linkage. If this hook returns false, then
5582 class data for classes whose virtual table will be emitted in
5583 only one translation unit will not be COMDAT. */
5585 (class_data_always_comdat,
5586 "This hook returns true (the default) if virtual tables and other\n\
5587 similar implicit class data objects are always COMDAT if they have\n\
5588 external linkage. If this hook returns false, then class data for\n\
5589 classes whose virtual table will be emitted in only one translation\n\
5590 unit will not be COMDAT.",
5592 hook_bool_void_true)
5594 /* Returns true (the default) if the RTTI for the basic types,
5595 which is always defined in the C++ runtime, should be COMDAT;
5596 false if it should not be COMDAT. */
5598 (library_rtti_comdat,
5599 "This hook returns true (the default) if the RTTI information for\n\
5600 the basic types which is defined in the C++ runtime should always\n\
5601 be COMDAT, false if it should not be COMDAT.",
5603 hook_bool_void_true)
5605 /* Returns true if __aeabi_atexit should be used to register static
5609 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
5610 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
5611 is in effect. The default is to return false to use @code{__cxa_atexit}.",
5613 hook_bool_void_false)
5615 /* Returns true if target may use atexit in the same manner as
5616 __cxa_atexit to register static destructors. */
5618 (use_atexit_for_cxa_atexit,
5619 "This hook returns true if the target @code{atexit} function can be used\n\
5620 in the same manner as @code{__cxa_atexit} to register C++ static\n\
5621 destructors. This requires that @code{atexit}-registered functions in\n\
5622 shared libraries are run in the correct order when the libraries are\n\
5623 unloaded. The default is to return false.",
5625 hook_bool_void_false)
5628 (adjust_class_at_definition,
5629 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
5630 been defined. Use this hook to make adjustments to the class (eg, tweak\
5631 visibility or perform any other required target modifications).",
5636 (decl_mangling_context,
5637 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
5638 tree, (const_tree decl),
5639 hook_tree_const_tree_null)
5641 HOOK_VECTOR_END (cxx)
5643 /* Functions and data for emulated TLS support. */
5645 #define HOOK_PREFIX "TARGET_EMUTLS_"
5646 HOOK_VECTOR (TARGET_EMUTLS, emutls)
5648 /* Name of the address and common functions. */
5651 "Contains the name of the helper function that uses a TLS control\n\
5652 object to locate a TLS instance. The default causes libgcc's\n\
5653 emulated TLS helper function to be used.",
5654 const char *, "__builtin___emutls_get_address")
5658 "Contains the name of the helper function that should be used at\n\
5659 program startup to register TLS objects that are implicitly\n\
5660 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
5661 have explicit initializers. The default causes libgcc's emulated TLS\n\
5662 registration function to be used.",
5663 const char *, "__builtin___emutls_register_common")
5665 /* Prefixes for proxy variable and template. */
5668 "Contains the name of the section in which TLS control variables should\n\
5669 be placed. The default of @code{NULL} allows these to be placed in\n\
5675 "Contains the name of the section in which TLS initializers should be\n\
5676 placed. The default of @code{NULL} allows these to be placed in any\n\
5680 /* Prefixes for proxy variable and template. */
5683 "Contains the prefix to be prepended to TLS control variable names.\n\
5684 The default of @code{NULL} uses a target-specific prefix.",
5689 "Contains the prefix to be prepended to TLS initializer objects. The\n\
5690 default of @code{NULL} uses a target-specific prefix.",
5693 /* Function to generate field definitions of the proxy variable. */
5696 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
5697 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
5698 @var{name} should be filled with the structure tag, if the default of\n\
5699 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
5700 for libgcc's emulated TLS function.",
5701 tree, (tree type, tree *name),
5702 default_emutls_var_fields)
5704 /* Function to initialize a proxy variable. */
5707 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
5708 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
5709 is the TLS object and @var{tmpl_addr} is the address of the\n\
5710 initializer. The default initializes libgcc's emulated TLS control object.",
5711 tree, (tree var, tree decl, tree tmpl_addr),
5712 default_emutls_var_init)
5714 /* Whether we are allowed to alter the usual alignment of the
5718 "Specifies whether the alignment of TLS control variable objects is\n\
5719 fixed and should not be increased as some backends may do to optimize\n\
5720 single objects. The default is false.",
5723 /* Whether we can emit debug information for TLS vars. */
5725 (debug_form_tls_address,
5726 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
5727 may be used to describe emulated TLS control objects.",
5730 HOOK_VECTOR_END (emutls)
5733 #define HOOK_PREFIX "TARGET_OPTION_"
5734 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
5736 /* Function to validate the attribute((target(...))) strings. If
5737 the option is validated, the hook should also fill in
5738 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
5741 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
5742 allows setting target-specific options on individual functions.\n\
5743 These function-specific options may differ\n\
5744 from the options specified on the command line. The hook should return\n\
5745 @code{true} if the options are valid.\n\
5747 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
5748 the function declaration to hold a pointer to a target-specific\n\
5749 @code{struct cl_target_option} structure.",
5750 bool, (tree fndecl, tree name, tree args, int flags),
5751 default_target_option_valid_attribute_p)
5753 /* Function to save any extra target state in the target options structure. */
5756 "This hook is called to save any additional target-specific information\n\
5757 in the @code{struct cl_target_option} structure for function-specific\n\
5758 options from the @code{struct gcc_options} structure.\n\
5759 @xref{Option file format}.",
5760 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
5762 /* Function to restore any extra target state from the target options
5766 "This hook is called to restore any additional target-specific\n\
5767 information in the @code{struct cl_target_option} structure for\n\
5768 function-specific options to the @code{struct gcc_options} structure.",
5769 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
5771 /* Function to update target-specific option information after being
5775 "This hook is called to update target-specific information in the\n\
5776 @code{struct cl_target_option} structure after it is streamed in from\n\
5778 void, (struct cl_target_option *ptr), NULL)
5780 /* Function to print any extra target state from the target options
5784 "This hook is called to print any additional target-specific\n\
5785 information in the @code{struct cl_target_option} structure for\n\
5786 function-specific options.",
5787 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
5789 /* Function to parse arguments to be validated for #pragma target, and to
5790 change the state if the options are valid. If the first argument is
5791 NULL, the second argument specifies the default options to use. Return
5792 true if the options are valid, and set the current state. */
5795 "This target hook parses the options for @code{#pragma GCC target}, which\n\
5796 sets the target-specific options for functions that occur later in the\n\
5797 input stream. The options accepted should be the same as those handled by the\n\
5798 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
5799 bool, (tree args, tree pop_target),
5800 default_target_option_pragma_parse)
5802 /* Do option overrides for the target. */
5805 "Sometimes certain combinations of command options do not make sense on\n\
5806 a particular target machine. You can override the hook\n\
5807 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
5808 once just after all the command options have been parsed.\n\
5810 Don't use this hook to turn on various extra optimizations for\n\
5811 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
5813 If you need to do something whenever the optimization level is\n\
5814 changed via the optimize attribute or pragma, see\n\
5815 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
5819 /* This function returns true if DECL1 and DECL2 are versions of the same
5820 function. DECL1 and DECL2 are function versions if and only if they
5821 have the same function signature and different target specific attributes,
5822 that is, they are compiled for different target machines. */
5825 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
5826 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
5827 versions if and only if they have the same function signature and\n\
5828 different target specific attributes, that is, they are compiled for\n\
5829 different target machines.",
5830 bool, (tree decl1, tree decl2),
5831 hook_bool_tree_tree_false)
5833 /* Function to determine if one function can inline another function. */
5835 #define HOOK_PREFIX "TARGET_"
5838 "This target hook returns @code{false} if the @var{caller} function\n\
5839 cannot inline @var{callee}, based on target specific information. By\n\
5840 default, inlining is not allowed if the callee function has function\n\
5841 specific target options and the caller does not use the same options.",
5842 bool, (tree caller, tree callee),
5843 default_target_can_inline_p)
5847 "This target hook fixes function @var{fndecl} after attributes are processed. Default does nothing. On ARM, the default function's alignment is updated with the attribute target.",
5848 void, (tree fndecl),
5851 HOOK_VECTOR_END (target_option)
5853 /* For targets that need to mark extra registers as live on entry to
5854 the function, they should define this target hook and set their
5855 bits in the bitmap passed in. */
5857 (extra_live_on_entry,
5858 "Add any hard registers to @var{regs} that are live on entry to the\n\
5859 function. This hook only needs to be defined to provide registers that\n\
5860 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
5861 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
5862 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
5863 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
5864 void, (bitmap regs),
5867 /* Targets should define this target hook to mark that non-callee clobbers are
5868 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
5871 (call_fusage_contains_non_callee_clobbers,
5872 "Set to true if each call that binds to a local definition explicitly\n\
5873 clobbers or sets all non-fixed registers modified by performing the call.\n\
5874 That is, by the call pattern itself, or by code that might be inserted by the\n\
5875 linker (e.g. stubs, veneers, branch islands), but not including those\n\
5876 modifiable by the callee. The affected registers may be mentioned explicitly\n\
5877 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
5878 The default version of this hook is set to false. The purpose of this hook\n\
5879 is to enable the fipa-ra optimization.",
5883 /* Fill in additional registers set up by prologue into a regset. */
5885 (set_up_by_prologue,
5886 "This hook should add additional registers that are computed by the prologue\
5887 to the hard regset for shrink-wrapping optimization purposes.",
5888 void, (struct hard_reg_set_container *),
5891 /* For targets that have attributes that can affect whether a
5892 function's return statements need checking. For instance a 'naked'
5893 function attribute. */
5896 "True if a function's return statements should be checked for matching the function's return type. This includes checking for falling off the end of a non-void function. Return false if no such check should be made.",
5898 hook_bool_tree_true)
5901 #define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
5902 HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
5905 (get_separate_components,
5906 "This hook should return an @code{sbitmap} with the bits set for those\n\
5907 components that can be separately shrink-wrapped in the current function.\n\
5908 Return @code{NULL} if the current function should not get any separate\n\
5910 Don't define this hook if it would always return @code{NULL}.\n\
5911 If it is defined, the other hooks in this group have to be defined as well.",
5917 "This hook should return an @code{sbitmap} with the bits set for those\n\
5918 components where either the prologue component has to be executed before\n\
5919 the @code{basic_block}, or the epilogue component after it, or both.",
5920 sbitmap, (basic_block),
5924 (disqualify_components,
5925 "This hook should clear the bits in the @var{components} bitmap for those\n\
5926 components in @var{edge_components} that the target cannot handle on edge\n\
5927 @var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
5929 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
5933 (emit_prologue_components,
5934 "Emit prologue insns for the components indicated by the parameter.",
5939 (emit_epilogue_components,
5940 "Emit epilogue insns for the components indicated by the parameter.",
5945 (set_handled_components,
5946 "Mark the components in the parameter as handled, so that the\n\
5947 @code{prologue} and @code{epilogue} named patterns know to ignore those\n\
5948 components. The target code should not hang on to the @code{sbitmap}, it\n\
5949 will be deleted after this call.",
5953 HOOK_VECTOR_END (shrink_wrap)
5955 #define HOOK_PREFIX "TARGET_"
5957 /* Determine the type of unwind info to emit for debugging. */
5960 "This hook defines the mechanism that will be used for describing frame\n\
5961 unwind information to the debugger. Normally the hook will return\n\
5962 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
5963 return @code{UI_NONE} otherwise.\n\
5965 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
5966 is disabled in order to always output DWARF 2 frame information.\n\
5968 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
5969 This will suppress generation of the normal debug frame unwind information.",
5970 enum unwind_info_type, (void),
5971 default_debug_unwind_info)
5973 /* The code parameter should be of type enum rtx_code but this is not
5974 defined at this time. */
5976 (canonicalize_comparison,
5977 "On some machines not all possible comparisons are defined, but you can\n\
5978 convert an invalid comparison into a valid one. For example, the Alpha\n\
5979 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
5980 comparison instead and swap the order of the operands.\n\
5982 On such machines, implement this hook to do any required conversions.\n\
5983 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
5984 are the left and right operands of the comparison, respectively. If\n\
5985 @var{op0_preserve_value} is @code{true} the implementation is not\n\
5986 allowed to change the value of @var{op0} since the value might be used\n\
5987 in RTXs which aren't comparisons. E.g. the implementation is not\n\
5988 allowed to swap operands in that case.\n\
5990 GCC will not assume that the comparison resulting from this macro is\n\
5991 valid but will see if the resulting insn matches a pattern in the\n\
5994 You need not to implement this hook if it would never change the\n\
5995 comparison code or operands.",
5996 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
5997 default_canonicalize_comparison)
6000 (min_arithmetic_precision,
6001 "On some RISC architectures with 64-bit registers, the processor also\n\
6002 maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6003 arithmetic, although the operations are performed on the full registers.\n\
6005 On such architectures, defining this hook to 32 tells the compiler to try\n\
6006 using 32-bit arithmetical operations setting the condition codes instead\n\
6007 of doing full 64-bit arithmetic.\n\
6009 More generally, define this hook on RISC architectures if you want the\n\
6010 compiler to try using arithmetical operations setting the condition codes\n\
6011 with a precision lower than the word precision.\n\
6013 You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6015 unsigned int, (void), default_min_arithmetic_precision)
6018 (atomic_test_and_set_trueval,
6019 "This value should be set if the result written by\
6020 @code{atomic_test_and_set} is not exactly 1, i.e. the\
6021 @code{bool} @code{true}.",
6024 /* Return an unsigned int representing the alignment (in bits) of the atomic
6025 type which maps to machine MODE. This allows alignment to be overridden
6028 (atomic_align_for_mode,
6029 "If defined, this function returns an appropriate alignment in bits for an\
6030 atomic object of machine_mode @var{mode}. If 0 is returned then the\
6031 default alignment for the specified mode is used. ",
6032 unsigned int, (machine_mode mode),
6036 (atomic_assign_expand_fenv,
6037 "ISO C11 requires atomic compound assignments that may raise floating-point\
6038 exceptions to raise exceptions corresponding to the arithmetic operation\
6039 whose result was successfully stored in a compare-and-exchange sequence. \
6040 This requires code equivalent to calls to @code{feholdexcept},\
6041 @code{feclearexcept} and @code{feupdateenv} to be generated at\
6042 appropriate points in the compare-and-exchange sequence. This hook should\
6043 set @code{*@var{hold}} to an expression equivalent to the call to\
6044 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
6045 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
6046 equivalent to the call to @code{feupdateenv}. The three expressions are\
6047 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
6048 if no code is required in a particular place. The default implementation\
6049 leaves all three expressions as @code{NULL_TREE}. The\
6050 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
6051 as part of the code generated in @code{*@var{update}}.",
6052 void, (tree *hold, tree *clear, tree *update),
6053 default_atomic_assign_expand_fenv)
6055 /* Leave the boolean fields at the end. */
6057 /* True if we can create zeroed data by switching to a BSS section
6058 and then using ASM_OUTPUT_SKIP to allocate the space. */
6060 (have_switchable_bss_sections,
6061 "This flag is true if we can create zeroed data by switching to a BSS\n\
6062 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
6063 This is true on most ELF targets.",
6066 /* True if "native" constructors and destructors are supported,
6067 false if we're using collect2 for the job. */
6070 "This value is true if the target supports some ``native'' method of\n\
6071 collecting constructors and destructors to be run at startup and exit.\n\
6072 It is false if we must use @command{collect2}.",
6075 /* True if thread-local storage is supported. */
6078 "Contains the value true if the target supports thread-local storage.\n\
6079 The default value is false.",
6082 /* True if a small readonly data section is supported. */
6084 (have_srodata_section,
6085 "Contains the value true if the target places read-only\n\
6086 ``small data'' into a separate section. The default value is false.",
6089 /* True if EH frame info sections should be zero-terminated. */
6091 (terminate_dw2_eh_frame_info,
6092 "Contains the value true if the target should add a zero word onto the\n\
6093 end of a Dwarf-2 frame info section when used for exception handling.\n\
6094 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
6098 /* True if #NO_APP should be emitted at the beginning of assembly output. */
6100 (asm_file_start_app_off,
6101 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
6102 printed as the very first line in the assembly file, unless\n\
6103 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
6104 to the empty string, this variable has no effect.) With the normal\n\
6105 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
6106 assembler that it need not bother stripping comments or extra\n\
6107 whitespace from its input. This allows it to work a bit faster.\n\
6109 The default is false. You should not set it to true unless you have\n\
6110 verified that your port does not generate any extra whitespace or\n\
6111 comments that will cause GAS to issue errors in NO_APP mode.",
6114 /* True if output_file_directive should be called for main_input_filename
6115 at the beginning of assembly output. */
6117 (asm_file_start_file_directive,
6118 "If this flag is true, @code{output_file_directive} will be called\n\
6119 for the primary source file, immediately after printing\n\
6120 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
6121 this to be done. The default is false.",
6124 /* Returns true if we should generate exception tables for use with the
6125 ARM EABI. The effects the encoding of function exception specifications. */
6128 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
6129 based unwinding library, and @code{false} on other targets. This effects\n\
6130 the format of unwinding tables, and how the unwinder in entered after\n\
6131 running a cleanup. The default is @code{false}.",
6135 (want_debug_pub_sections,
6136 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
6137 should be emitted. These sections are not used on most platforms, and\
6138 in particular GDB does not use them.",
6142 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
6143 This usually means it will be run as part of machine-specific reorg.",
6147 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
6148 This usually means it will be run as part of machine-specific reorg.",
6152 (no_register_allocation, "True if register allocation and the passes\n\
6153 following it should not be run. Usually true only for virtual assembler\n\
6157 /* Leave the boolean fields at the end. */
6159 /* Functions related to mode switching. */
6161 #define HOOK_PREFIX "TARGET_MODE_"
6162 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
6166 "Generate one or more insns to set @var{entity} to @var{mode}. @var{hard_reg_live} is the set of hard registers live at the point where the insn(s) are to be inserted. @var{prev_moxde} indicates the mode to switch from. Sets of a lower numbered entity will be emitted before sets of a higher numbered entity to a mode of the same or lower priority.",
6167 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
6171 "@var{entity} is an integer specifying a mode-switched entity. If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to return an integer value not larger than the corresponding element in @code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must be switched into prior to the execution of @var{insn}.",
6172 int, (int entity, rtx_insn *insn), NULL)
6176 "@var{entity} is an integer specifying a mode-switched entity. If this macro is defined, it is evaluated for every @var{insn} during mode switching. It determines the mode that an insn results in (if different from the incoming mode).",
6177 int, (int entity, int mode, rtx_insn *insn), NULL)
6181 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function entry. If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT} must be defined.",
6182 int, (int entity), NULL)
6186 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function exit. If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY} must be defined.",
6187 int, (int entity), NULL)
6191 "This macro specifies the order in which modes for @var{entity} are processed. 0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest. The value of the macro should be an integer designating a mode for @var{entity}. For any fixed @var{entity}, @code{mode_priority} (@var{entity}, @var{n}) shall be a bijection in 0 @dots{} @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
6192 int, (int entity, int n), NULL)
6194 HOOK_VECTOR_END (mode_switching)
6197 #define HOOK_PREFIX "TARGET_"
6199 #define DEF_TARGET_INSN(NAME, PROTO) \
6200 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
6201 #include "target-insns.def"
6202 #undef DEF_TARGET_INSN
6204 #define DEF_TARGET_INSN(NAME, PROTO) \
6205 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
6206 #include "target-insns.def"
6207 #undef DEF_TARGET_INSN
6209 #define DEF_TARGET_INSN(NAME, PROTO) \
6210 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
6211 #include "target-insns.def"
6212 #undef DEF_TARGET_INSN
6215 (run_target_selftests,
6216 "If selftests are enabled, run any selftests for this target.",
6220 /* Close the 'struct gcc_target' definition. */
6221 HOOK_VECTOR_END (C90_EMPTY_HACK)