1 /* Target hook definitions.
2 Copyright (C) 2001-2015 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 /* Return preferred text (sub)section for function DECL.
436 Main purpose of this function is to separate cold, normal and hot
437 functions. STARTUP is true when function is known to be used only
438 at startup (from static constructors or it is main()).
439 EXIT is true when function is known to be used only at exit
440 (from static destructors).
441 Return NULL if function should go to default text section. */
444 "Return preferred text (sub)section for function @var{decl}.\n\
445 Main purpose of this function is to separate cold, normal and hot\n\
446 functions. @var{startup} is true when function is known to be used only\n\
447 at startup (from static constructors or it is @code{main()}).\n\
448 @var{exit} is true when function is known to be used only at exit\n\
449 (from static destructors).\n\
450 Return NULL if function should go to default text section.",
451 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
452 default_function_section)
454 /* Output the assembler code for function exit. */
456 (function_switched_text_sections,
457 "Used by the target to emit any assembler directives or additional\
458 labels needed when a function is partitioned between different\
459 sections. Output should be written to @var{file}. The function\
460 decl is available as @var{decl} and the new section is `cold' if\
461 @var{new_is_cold} is @code{true}.",
462 void, (FILE *file, tree decl, bool new_is_cold),
463 default_function_switched_text_sections)
465 /* Return a mask describing how relocations should be treated when
466 selecting sections. Bit 1 should be set if global relocations
467 should be placed in a read-write section; bit 0 should be set if
468 local relocations should be placed in a read-write section. */
471 "Return a mask describing how relocations should be treated when\n\
472 selecting sections. Bit 1 should be set if global relocations\n\
473 should be placed in a read-write section; bit 0 should be set if\n\
474 local relocations should be placed in a read-write section.\n\
476 The default version of this function returns 3 when @option{-fpic}\n\
477 is in effect, and 0 otherwise. The hook is typically redefined\n\
478 when the target cannot support (some kinds of) dynamic relocations\n\
479 in read-only sections even in executables.",
481 default_reloc_rw_mask)
483 /* Return a section for EXP. It may be a DECL or a constant. RELOC
484 is nonzero if runtime relocations must be applied; bit 1 will be
485 set if the runtime relocations require non-local name resolution.
486 ALIGN is the required alignment of the data. */
489 "Return the section into which @var{exp} should be placed. You can\n\
490 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
491 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
492 requires link-time relocations. Bit 0 is set when variable contains\n\
493 local relocations only, while bit 1 is set for global relocations.\n\
494 @var{align} is the constant alignment in bits.\n\
496 The default version of this function takes care of putting read-only\n\
497 variables in @code{readonly_data_section}.\n\
499 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
500 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
501 default_select_section)
503 /* Return a section for X. MODE is X's mode and ALIGN is its
504 alignment in bits. */
507 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
508 should be placed. You can assume that @var{x} is some kind of\n\
509 constant in RTL@. The argument @var{mode} is redundant except in the\n\
510 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
513 The default version of this function takes care of putting symbolic\n\
514 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
515 else in @code{readonly_data_section}.",
516 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
517 default_select_rtx_section)
519 /* Select a unique section name for DECL. RELOC is the same as
520 for SELECT_SECTION. */
523 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
524 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
525 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
526 the initial value of @var{exp} requires link-time relocations.\n\
528 The default version of this function appends the symbol name to the\n\
529 ELF section name that would normally be used for the symbol. For\n\
530 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
531 Whatever the actual target object format, this is often good enough.",
532 void, (tree decl, int reloc),
533 default_unique_section)
535 /* Return the readonly data section associated with function DECL. */
537 (function_rodata_section,
538 "Return the readonly data section associated with\n\
539 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
540 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
541 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
542 if function is in @code{.text.name}, and the normal readonly-data section\n\
544 section *, (tree decl),
545 default_function_rodata_section)
547 /* Nonnull if the target wants to override the default ".rodata" prefix
548 for mergeable data sections. */
550 (mergeable_rodata_prefix,
551 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
552 section names for mergeable constant data. Define this macro to override\n\
553 the string if a different section name should be used.",
554 const char *, ".rodata")
556 /* Return the section to be used for transactional memory clone tables. */
558 (tm_clone_table_section,
559 "Return the section that should be used for transactional memory clone\
561 section *, (void), default_clone_table_section)
563 /* Output a constructor for a symbol with a given priority. */
566 "If defined, a function that outputs assembler code to arrange to call\n\
567 the function referenced by @var{symbol} at initialization time.\n\
569 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
570 no arguments and with no return value. If the target supports initialization\n\
571 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
572 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
574 If this macro is not defined by the target, a suitable default will\n\
575 be chosen if (1) the target supports arbitrary section names, (2) the\n\
576 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
578 void, (rtx symbol, int priority), NULL)
580 /* Output a destructor for a symbol with a given priority. */
583 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
584 functions rather than initialization functions.",
585 void, (rtx symbol, int priority), NULL)
587 /* Output the assembler code for a thunk function. THUNK_DECL is the
588 declaration for the thunk function itself, FUNCTION is the decl for
589 the target function. DELTA is an immediate constant offset to be
590 added to THIS. If VCALL_OFFSET is nonzero, the word at
591 *(*this + vcall_offset) should be added to THIS. */
594 "A function that outputs the assembler code for a thunk\n\
595 function, used to implement C++ virtual function calls with multiple\n\
596 inheritance. The thunk acts as a wrapper around a virtual function,\n\
597 adjusting the implicit object parameter before handing control off to\n\
598 the real function.\n\
600 First, emit code to add the integer @var{delta} to the location that\n\
601 contains the incoming first argument. Assume that this argument\n\
602 contains a pointer, and is the one used to pass the @code{this} pointer\n\
603 in C++. This is the incoming argument @emph{before} the function prologue,\n\
604 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
605 all other incoming arguments.\n\
607 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
608 made after adding @code{delta}. In particular, if @var{p} is the\n\
609 adjusted pointer, the following adjustment should be made:\n\
612 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
615 After the additions, emit code to jump to @var{function}, which is a\n\
616 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
617 not touch the return address. Hence returning from @var{FUNCTION} will\n\
618 return to whoever called the current @samp{thunk}.\n\
620 The effect must be as if @var{function} had been called directly with\n\
621 the adjusted first argument. This macro is responsible for emitting all\n\
622 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
623 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
625 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
626 have already been extracted from it.) It might possibly be useful on\n\
627 some targets, but probably not.\n\
629 If you do not define this macro, the target-independent code in the C++\n\
630 front end will generate a less efficient heavyweight thunk that calls\n\
631 @var{function} instead of jumping to it. The generic approach does\n\
632 not support varargs.",
633 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
634 HOST_WIDE_INT vcall_offset, tree function),
637 /* Determine whether output_mi_thunk would succeed. */
638 /* ??? Ideally, this hook would not exist, and success or failure
639 would be returned from output_mi_thunk directly. But there's
640 too much undo-able setup involved in invoking output_mi_thunk.
641 Could be fixed by making output_mi_thunk emit rtl instead of
642 text to the output file. */
644 (can_output_mi_thunk,
645 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
646 to output the assembler code for the thunk function specified by the\n\
647 arguments it is passed, and false otherwise. In the latter case, the\n\
648 generic approach will be used by the C++ front end, with the limitations\n\
649 previously exposed.",
650 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
651 HOST_WIDE_INT vcall_offset, const_tree function),
652 hook_bool_const_tree_hwi_hwi_const_tree_false)
654 /* Output any boilerplate text needed at the beginning of a
658 "Output to @code{asm_out_file} any text which the assembler expects to\n\
659 find at the beginning of a file. The default behavior is controlled\n\
660 by two flags, documented below. Unless your target's assembler is\n\
661 quite unusual, if you override the default, you should call\n\
662 @code{default_file_start} at some point in your target hook. This\n\
663 lets other target files rely on these variables.",
667 /* Output any boilerplate text needed at the end of a translation unit. */
670 "Output to @code{asm_out_file} any text which the assembler expects\n\
671 to find at the end of a file. The default is to output nothing.",
675 /* Output any boilerplate text needed at the beginning of an
676 LTO output stream. */
679 "Output to @code{asm_out_file} any text which the assembler expects\n\
680 to find at the start of an LTO section. The default is to output\n\
685 /* Output any boilerplate text needed at the end of an
686 LTO output stream. */
689 "Output to @code{asm_out_file} any text which the assembler expects\n\
690 to find at the end of an LTO section. The default is to output\n\
695 /* Output any boilerplace text needed at the end of a
696 translation unit before debug and unwind info is emitted. */
699 "Output to @code{asm_out_file} any text which is needed before emitting\n\
700 unwind info and debug info at the end of a file. Some targets emit\n\
701 here PIC setup thunks that cannot be emitted at the end of file,\n\
702 because they couldn't have unwind info then. The default is to output\n\
707 /* Output an assembler pseudo-op to declare a library function name
711 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
712 pseudo-op to declare a library function name external. The name of the\n\
713 library function is given by @var{symref}, which is a @code{symbol_ref}.",
715 default_external_libcall)
717 /* Output an assembler directive to mark decl live. This instructs
718 linker to not dead code strip this symbol. */
720 (mark_decl_preserved,
721 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
722 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
723 .no_dead_code_strip directive.",
724 void, (const char *symbol),
725 hook_void_constcharptr)
727 /* Output a record of the command line switches that have been passed. */
729 (record_gcc_switches,
730 "Provides the target with the ability to record the gcc command line\n\
731 switches that have been passed to the compiler, and options that are\n\
732 enabled. The @var{type} argument specifies what is being recorded.\n\
733 It can take the following values:\n\
736 @item SWITCH_TYPE_PASSED\n\
737 @var{text} is a command line switch that has been set by the user.\n\
739 @item SWITCH_TYPE_ENABLED\n\
740 @var{text} is an option which has been enabled. This might be as a\n\
741 direct result of a command line switch, or because it is enabled by\n\
742 default or because it has been enabled as a side effect of a different\n\
743 command line switch. For example, the @option{-O2} switch enables\n\
744 various different individual optimization passes.\n\
746 @item SWITCH_TYPE_DESCRIPTIVE\n\
747 @var{text} is either NULL or some descriptive text which should be\n\
748 ignored. If @var{text} is NULL then it is being used to warn the\n\
749 target hook that either recording is starting or ending. The first\n\
750 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
751 warning is for start up and the second time the warning is for\n\
752 wind down. This feature is to allow the target hook to make any\n\
753 necessary preparations before it starts to record switches and to\n\
754 perform any necessary tidying up after it has finished recording\n\
757 @item SWITCH_TYPE_LINE_START\n\
758 This option can be ignored by this target hook.\n\
760 @item SWITCH_TYPE_LINE_END\n\
761 This option can be ignored by this target hook.\n\
764 The hook's return value must be zero. Other return values may be\n\
765 supported in the future.\n\
767 By default this hook is set to NULL, but an example implementation is\n\
768 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
769 it records the switches as ASCII text inside a new, string mergeable\n\
770 section in the assembler output file. The name of the new section is\n\
771 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
773 int, (print_switch_type type, const char *text),
776 /* The name of the section that the example ELF implementation of
777 record_gcc_switches will use to store the information. Target
778 specific versions of record_gcc_switches may or may not use
781 (record_gcc_switches_section,
782 "This is the name of the section that will be created by the example\n\
783 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
785 const char *, ".GCC.command.line")
787 /* Output the definition of a section anchor. */
790 "Write the assembly code to define section anchor @var{x}, which is a\n\
791 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
792 The hook is called with the assembly output position set to the beginning\n\
793 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
795 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
796 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
797 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
798 is @code{NULL}, which disables the use of section anchors altogether.",
800 default_asm_output_anchor)
804 "Output a string based on @var{name}, suitable for the @samp{#ident} \
805 directive, or the equivalent directive or pragma in non-C-family languages. \
806 If this hook is not defined, nothing is output for the @samp{#ident} \
808 void, (const char *name),
809 hook_void_constcharptr)
811 /* Output a DTP-relative reference to a TLS symbol. */
813 (output_dwarf_dtprel,
814 "If defined, this target hook is a function which outputs a DTP-relative\n\
815 reference to the given TLS symbol of the specified size.",
816 void, (FILE *file, int size, rtx x),
819 /* Some target machines need to postscan each insn after it is output. */
821 (final_postscan_insn,
822 "If defined, this target hook is a function which is executed just after the\n\
823 output of assembler code for @var{insn}, to change the mode of the assembler\n\
826 Here the argument @var{opvec} is the vector containing the operands\n\
827 extracted from @var{insn}, and @var{noperands} is the number of\n\
828 elements of the vector which contain meaningful data for this insn.\n\
829 The contents of this vector are what was used to convert the insn\n\
830 template into assembler code, so you can change the assembler mode\n\
831 by checking the contents of the vector.",
832 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
835 /* Emit the trampoline template. This hook may be NULL. */
837 (trampoline_template,
838 "This hook is called by @code{assemble_trampoline_template} to output,\n\
839 on the stream @var{f}, assembler code for a block of data that contains\n\
840 the constant parts of a trampoline. This code should not include a\n\
841 label---the label is taken care of automatically.\n\
843 If you do not define this hook, it means no template is needed\n\
844 for the target. Do not define this hook on systems where the block move\n\
845 code to copy the trampoline into place would be larger than the code\n\
846 to generate it on the spot.",
851 (output_source_filename,
852 "Output COFF information or DWARF debugging information which indicates\
853 that filename @var{name} is the current source file to the stdio\
854 stream @var{file}.\n\
856 This target hook need not be defined if the standard form of output\
857 for the file format in use is appropriate.",
858 void ,(FILE *file, const char *name),
859 default_asm_output_source_filename)
862 (output_addr_const_extra,
863 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
864 can't deal with, and output assembly code to @var{file} corresponding to\n\
865 the pattern @var{x}. This may be used to allow machine-dependent\n\
866 @code{UNSPEC}s to appear within constants.\n\
868 If target hook fails to recognize a pattern, it must return @code{false},\n\
869 so that a standard error message is printed. If it prints an error message\n\
870 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
871 return @code{true}.",
872 bool, (FILE *file, rtx x),
873 hook_bool_FILEptr_rtx_false)
875 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
876 even though that is not reflected in the macro name to override their
879 #define HOOK_PREFIX "TARGET_"
881 /* Emit a machine-specific insn operand. */
882 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
883 not this hook, and uses a different name for the argument FILE. */
887 void, (FILE *file, rtx x, int code),
888 default_print_operand)
890 /* Emit a machine-specific memory address. */
891 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
892 not this hook, and uses different argument names. */
894 (print_operand_address,
896 void, (FILE *file, rtx addr),
897 default_print_operand_address)
899 /* Determine whether CODE is a valid punctuation character for the
900 `print_operand' hook. */
901 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
904 (print_operand_punct_valid_p,
906 bool ,(unsigned char code),
907 default_print_operand_punct_valid_p)
909 /* Given a symbol name, perform same mangling as assemble_name and
910 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
912 (mangle_assembler_name,
913 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
914 @code{assemble_name}, but in memory rather than to a file stream, returning\
915 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
916 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
917 then prepends the @code{USER_LABEL_PREFIX}, if any.",
918 tree, (const char *name),
919 default_mangle_assembler_name)
921 HOOK_VECTOR_END (asm_out)
923 /* Functions relating to instruction scheduling. All of these
924 default to null pointers, which haifa-sched.c looks for and handles. */
926 #define HOOK_PREFIX "TARGET_SCHED_"
927 HOOK_VECTOR (TARGET_SCHED, sched)
929 /* Given the current cost, COST, of an insn, INSN, calculate and
930 return a new cost based on its relationship to DEP_INSN through
931 the dependence LINK. The default is to make no adjustment. */
934 "This function corrects the value of @var{cost} based on the\n\
935 relationship between @var{insn} and @var{dep_insn} through the\n\
936 dependence @var{link}. It should return the new value. The default\n\
937 is to make no adjustment to @var{cost}. This can be used for example\n\
938 to specify to the scheduler using the traditional pipeline description\n\
939 that an output- or anti-dependence does not incur the same cost as a\n\
940 data-dependence. If the scheduler using the automaton based pipeline\n\
941 description, the cost of anti-dependence is zero and the cost of\n\
942 output-dependence is maximum of one and the difference of latency\n\
943 times of the first and the second insns. If these values are not\n\
944 acceptable, you could use the hook to modify them too. See also\n\
945 @pxref{Processor pipeline description}.",
946 int, (rtx_insn *insn, rtx link, rtx_insn *dep_insn, int cost), NULL)
948 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
951 "This hook adjusts the integer scheduling priority @var{priority} of\n\
952 @var{insn}. It should return the new priority. Increase the priority to\n\
953 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
954 later. Do not define this hook if you do not need to adjust the\n\
955 scheduling priorities of insns.",
956 int, (rtx_insn *insn, int priority), NULL)
958 /* Function which returns the maximum number of insns that can be
959 scheduled in the same machine cycle. This must be constant
960 over an entire compilation. The default is 1. */
963 "This hook returns the maximum number of instructions that can ever\n\
964 issue at the same time on the target machine. The default is one.\n\
965 Although the insn scheduler can define itself the possibility of issue\n\
966 an insn on the same cycle, the value can serve as an additional\n\
967 constraint to issue insns on the same simulated processor cycle (see\n\
968 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
969 This value must be constant over the entire compilation. If you need\n\
970 it to vary depending on what the instructions are, you must use\n\
971 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
974 /* Calculate how much this insn affects how many more insns we
975 can emit this cycle. Default is they all cost the same. */
978 "This hook is executed by the scheduler after it has scheduled an insn\n\
979 from the ready list. It should return the number of insns which can\n\
980 still be issued in the current cycle. The default is\n\
981 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
982 @code{USE}, which normally are not counted against the issue rate.\n\
983 You should define this hook if some insns take more machine resources\n\
984 than others, so that fewer insns can follow them in the same cycle.\n\
985 @var{file} is either a null pointer, or a stdio stream to write any\n\
986 debug output to. @var{verbose} is the verbose level provided by\n\
987 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
989 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
991 /* Initialize machine-dependent scheduling code. */
994 "This hook is executed by the scheduler at the beginning of each block of\n\
995 instructions that are to be scheduled. @var{file} is either a null\n\
996 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
997 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
998 @var{max_ready} is the maximum number of insns in the current scheduling\n\
999 region that can be live at the same time. This can be used to allocate\n\
1000 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1001 void, (FILE *file, int verbose, int max_ready), NULL)
1003 /* Finalize machine-dependent scheduling code. */
1006 "This hook is executed by the scheduler at the end of each block of\n\
1007 instructions that are to be scheduled. It can be used to perform\n\
1008 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1009 is either a null pointer, or a stdio stream to write any debug output\n\
1010 to. @var{verbose} is the verbose level provided by\n\
1011 @option{-fsched-verbose-@var{n}}.",
1012 void, (FILE *file, int verbose), NULL)
1014 /* Initialize machine-dependent function wide scheduling code. */
1017 "This hook is executed by the scheduler after function level initializations.\n\
1018 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1019 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1020 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1021 void, (FILE *file, int verbose, int old_max_uid), NULL)
1023 /* Finalize machine-dependent function wide scheduling code. */
1026 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1027 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1028 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1029 void, (FILE *file, int verbose), NULL)
1031 /* Reorder insns in a machine-dependent fashion, in two different
1032 places. Default does nothing. */
1035 "This hook is executed by the scheduler after it has scheduled the ready\n\
1036 list, to allow the machine description to reorder it (for example to\n\
1037 combine two small instructions together on @samp{VLIW} machines).\n\
1038 @var{file} is either a null pointer, or a stdio stream to write any\n\
1039 debug output to. @var{verbose} is the verbose level provided by\n\
1040 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1041 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1042 a pointer to the number of elements in the ready list. The scheduler\n\
1043 reads the ready list in reverse order, starting with\n\
1044 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1045 is the timer tick of the scheduler. You may modify the ready list and\n\
1046 the number of ready insns. The return value is the number of insns that\n\
1047 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1048 @samp{TARGET_SCHED_REORDER2}.",
1049 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1053 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1054 function is called whenever the scheduler starts a new cycle. This one\n\
1055 is called once per iteration over a cycle, immediately after\n\
1056 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1057 return the number of insns to be scheduled in the same cycle. Defining\n\
1058 this hook can be useful if there are frequent situations where\n\
1059 scheduling one insn causes other insns to become ready in the same\n\
1060 cycle. These other insns can then be taken into account properly.",
1061 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1065 "This hook is used to check whether target platform supports macro fusion.",
1069 (macro_fusion_pair_p,
1070 "This hook is used to check whether two insns should be macro fused for\n\
1071 a target microarchitecture. If this hook returns true for the given insn pair\n\
1072 (@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1073 group, and they will not be scheduled apart. The two insns will be either\n\
1074 two SET insns or a compare and a conditional jump and this hook should\n\
1075 validate any dependencies needed to fuse the two insns together.",
1076 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1078 /* The following member value is a pointer to a function called
1079 after evaluation forward dependencies of insns in chain given
1080 by two parameter values (head and tail correspondingly). */
1082 (dependencies_evaluation_hook,
1083 "This hook is called after evaluation forward dependencies of insns in\n\
1084 chain given by two parameter values (@var{head} and @var{tail}\n\
1085 correspondingly) but before insns scheduling of the insn chain. For\n\
1086 example, it can be used for better insn classification if it requires\n\
1087 analysis of dependencies. This hook can use backward and forward\n\
1088 dependencies of the insn scheduler because they are already\n\
1090 void, (rtx_insn *head, rtx_insn *tail), NULL)
1092 /* The values of the following four members are pointers to functions
1093 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1094 dfa_post_cycle_insn give functions returning insns which are used to
1095 change the pipeline hazard recognizer state when the new simulated
1096 processor cycle correspondingly starts and finishes. The function
1097 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1098 used to initialize the corresponding insns. The default values of
1099 the members result in not changing the automaton state when the
1100 new simulated processor cycle correspondingly starts and finishes. */
1103 (init_dfa_pre_cycle_insn,
1104 "The hook can be used to initialize data used by the previous hook.",
1108 (dfa_pre_cycle_insn,
1109 "The hook returns an RTL insn. The automaton state used in the\n\
1110 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1111 when the new simulated processor cycle starts. Usage of the hook may\n\
1112 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1113 processors. If the hook is defined, it is used only for the automaton\n\
1114 based pipeline description. The default is not to change the state\n\
1115 when the new simulated processor cycle starts.",
1119 (init_dfa_post_cycle_insn,
1120 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1121 used to initialize data used by the previous hook.",
1125 (dfa_post_cycle_insn,
1126 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1127 to changed the state as if the insn were scheduled when the new\n\
1128 simulated processor cycle finishes.",
1129 rtx_insn *, (void), NULL)
1131 /* The values of the following two members are pointers to
1132 functions used to simplify the automaton descriptions.
1133 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1134 immediately before and after cycle is advanced. */
1137 (dfa_pre_advance_cycle,
1138 "The hook to notify target that the current simulated cycle is about to finish.\n\
1139 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1140 to change the state in more complicated situations - e.g., when advancing\n\
1141 state on a single insn is not enough.",
1145 (dfa_post_advance_cycle,
1146 "The hook to notify target that new simulated cycle has just started.\n\
1147 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1148 to change the state in more complicated situations - e.g., when advancing\n\
1149 state on a single insn is not enough.",
1152 /* The following member value is a pointer to a function returning value
1153 which defines how many insns in queue `ready' will we try for
1154 multi-pass scheduling. If the member value is nonzero and the
1155 function returns positive value, the DFA based scheduler will make
1156 multi-pass scheduling for the first cycle. In other words, we will
1157 try to choose ready insn which permits to start maximum number of
1158 insns on the same cycle. */
1160 (first_cycle_multipass_dfa_lookahead,
1161 "This hook controls better choosing an insn from the ready insn queue\n\
1162 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1163 chooses the first insn from the queue. If the hook returns a positive\n\
1164 value, an additional scheduler code tries all permutations of\n\
1165 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1166 subsequent ready insns to choose an insn whose issue will result in\n\
1167 maximal number of issued insns on the same cycle. For the\n\
1168 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1169 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1170 rules of @acronym{VLIW} packing are described in the automaton.\n\
1172 This code also could be used for superscalar @acronym{RISC}\n\
1173 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1174 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1175 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1176 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1177 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1178 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1179 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1180 the processor could issue all 3 insns per cycle.\n\
1182 Actually this code demonstrates advantages of the automaton based\n\
1183 pipeline hazard recognizer. We try quickly and easy many insn\n\
1184 schedules to choose the best one.\n\
1186 The default is no multipass scheduling.",
1189 /* The following member value is pointer to a function controlling
1190 what insns from the ready insn queue will be considered for the
1191 multipass insn scheduling. If the hook returns zero for insn
1192 passed as the parameter, the insn will be not chosen to be issued. */
1194 (first_cycle_multipass_dfa_lookahead_guard,
1196 This hook controls what insns from the ready insn queue will be\n\
1197 considered for the multipass insn scheduling. If the hook returns\n\
1198 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1199 Positive return values will remove @var{insn} from consideration on\n\
1200 the current round of multipass scheduling.\n\
1201 Negative return values will remove @var{insn} from consideration for given\n\
1202 number of cycles.\n\
1203 Backends should be careful about returning non-zero for highest priority\n\
1204 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1205 to allow backends make correct judgements.\n\
1207 The default is that any ready insns can be chosen to be issued.",
1208 int, (rtx_insn *insn, int ready_index), NULL)
1210 /* This hook prepares the target for a new round of multipass
1212 DATA is a pointer to target-specific data used for multipass scheduling.
1213 READY_TRY and N_READY represent the current state of search in the
1214 optimization space. The target can filter out instructions that
1215 should not be tried during current round by setting corresponding
1216 elements in READY_TRY to non-zero.
1217 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1218 scheduling on current cycle. */
1220 (first_cycle_multipass_begin,
1221 "This hook prepares the target backend for a new round of multipass\n\
1223 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1226 /* This hook is called when multipass scheduling evaluates instruction INSN.
1227 DATA is a pointer to target-specific data that can be used to record effects
1228 of INSN on CPU that are not described in DFA.
1229 READY_TRY and N_READY represent the current state of search in the
1230 optimization space. The target can filter out instructions that
1231 should not be tried after issuing INSN by setting corresponding
1232 elements in READY_TRY to non-zero.
1233 INSN is the instruction being evaluated.
1234 PREV_DATA is a pointer to target-specific data corresponding
1235 to a state before issuing INSN. */
1237 (first_cycle_multipass_issue,
1238 "This hook is called when multipass scheduling evaluates instruction INSN.",
1239 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1240 const void *prev_data), NULL)
1242 /* This hook is called when multipass scheduling backtracks from evaluation of
1243 instruction corresponding to DATA.
1244 DATA is a pointer to target-specific data that stores the effects
1245 of instruction from which the algorithm backtracks on CPU that are not
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. */
1252 (first_cycle_multipass_backtrack,
1253 "This is called when multipass scheduling backtracks from evaluation of\n\
1255 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1257 /* This hook notifies the target about the result of the concluded current
1258 round of multipass scheduling.
1260 If DATA is non-NULL it points to target-specific data used for multipass
1261 scheduling which corresponds to instruction at the start of the chain of
1262 the winning solution. DATA is NULL when multipass scheduling cannot find
1263 a good enough solution on current cycle and decides to retry later,
1264 usually after advancing the cycle count. */
1266 (first_cycle_multipass_end,
1267 "This hook notifies the target about the result of the concluded current\n\
1268 round of multipass scheduling.",
1269 void, (const void *data), NULL)
1271 /* This hook is called to initialize target-specific data for multipass
1272 scheduling after it has been allocated.
1273 DATA is a pointer to target-specific data that stores the effects
1274 of instruction from which the algorithm backtracks on CPU that are not
1275 described in DFA. */
1277 (first_cycle_multipass_init,
1278 "This hook initializes target-specific data used in multipass scheduling.",
1279 void, (void *data), NULL)
1281 /* This hook is called to finalize target-specific data for multipass
1282 scheduling before it is deallocated.
1283 DATA is a pointer to target-specific data that stores the effects
1284 of instruction from which the algorithm backtracks on CPU that are not
1285 described in DFA. */
1287 (first_cycle_multipass_fini,
1288 "This hook finalizes target-specific data used in multipass scheduling.",
1289 void, (void *data), NULL)
1291 /* The following member value is pointer to a function called by
1292 the insn scheduler before issuing insn passed as the third
1293 parameter on given cycle. If the hook returns nonzero, the
1294 insn is not issued on given processors cycle. Instead of that,
1295 the processor cycle is advanced. If the value passed through
1296 the last parameter is zero, the insn ready queue is not sorted
1297 on the new cycle start as usually. The first parameter passes
1298 file for debugging output. The second one passes the scheduler
1299 verbose level of the debugging output. The forth and the fifth
1300 parameter values are correspondingly processor cycle on which
1301 the previous insn has been issued and the current processor cycle. */
1304 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1305 on cycle @var{clock}. If the hook returns nonzero,\n\
1306 @var{insn} is not issued on this processor cycle. Instead,\n\
1307 the processor cycle is advanced. If *@var{sort_p}\n\
1308 is zero, the insn ready queue is not sorted on the new cycle\n\
1309 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1310 verbosity level to use for debugging output.\n\
1311 @var{last_clock} and @var{clock} are, respectively, the\n\
1312 processor cycle on which the previous insn has been issued,\n\
1313 and the current processor cycle.",
1314 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1315 int clock, int *sort_p),
1318 /* The following member value is a pointer to a function called by the
1319 insn scheduler. It should return true if there exists a dependence
1320 which is considered costly by the target, between the insn
1321 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1322 the dep that represents the dependence between the two insns. The
1323 second argument is the cost of the dependence as estimated by
1324 the scheduler. The last argument is the distance in cycles
1325 between the already scheduled insn (first parameter) and the
1326 second insn (second parameter). */
1328 (is_costly_dependence,
1329 "This hook is used to define which dependences are considered costly by\n\
1330 the target, so costly that it is not advisable to schedule the insns that\n\
1331 are involved in the dependence too close to one another. The parameters\n\
1332 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1333 being evaluated. The second parameter @var{cost} is the cost of the\n\
1334 dependence as estimated by the scheduler, and the third\n\
1335 parameter @var{distance} is the distance in cycles between the two insns.\n\
1336 The hook returns @code{true} if considering the distance between the two\n\
1337 insns the dependence between them is considered costly by the target,\n\
1338 and @code{false} otherwise.\n\
1340 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1341 where (a) it's practically hopeless to predict the actual data/resource\n\
1342 delays, however: (b) there's a better chance to predict the actual grouping\n\
1343 that will be formed, and (c) correctly emulating the grouping can be very\n\
1344 important. In such targets one may want to allow issuing dependent insns\n\
1345 closer to one another---i.e., closer than the dependence distance; however,\n\
1346 not in cases of ``costly dependences'', which this hooks allows to define.",
1347 bool, (struct _dep *_dep, int cost, int distance), NULL)
1351 "Given the current cost, @var{cost}, of an insn, @var{insn}, calculate and\
1352 return a new cost based on its relationship to @var{dep_insn} through the\
1353 dependence of weakness @var{dw}. The default is to make no adjustment.",
1354 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
1358 /* The following member value is a pointer to a function called
1359 by the insn scheduler. This hook is called to notify the backend
1360 that new instructions were emitted. */
1363 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1364 the instruction stream. The hook notifies a target backend to extend its\n\
1365 per instruction data structures.",
1368 /* Next 5 functions are for multi-point scheduling. */
1370 /* Allocate memory for scheduler context. */
1372 (alloc_sched_context,
1373 "Return a pointer to a store large enough to hold target scheduling context.",
1374 void *, (void), NULL)
1376 /* Fills the context from the local machine scheduler context. */
1378 (init_sched_context,
1379 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1380 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1381 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1382 void, (void *tc, bool clean_p), NULL)
1384 /* Sets local machine scheduler context to a saved value. */
1387 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1388 void, (void *tc), NULL)
1390 /* Clears a scheduler context so it becomes like after init. */
1392 (clear_sched_context,
1393 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1394 void, (void *tc), NULL)
1396 /* Frees the scheduler context. */
1398 (free_sched_context,
1399 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1400 void, (void *tc), NULL)
1402 /* The following member value is a pointer to a function called
1403 by the insn scheduler.
1404 The first parameter is an instruction, the second parameter is the type
1405 of the requested speculation, and the third parameter is a pointer to the
1406 speculative pattern of the corresponding type (set if return value == 1).
1408 -1, if there is no pattern, that will satisfy the requested speculation type,
1409 0, if current pattern satisfies the requested speculation type,
1410 1, if pattern of the instruction should be changed to the newly
1414 "This hook is called by the insn scheduler when @var{insn} has only\n\
1415 speculative dependencies and therefore can be scheduled speculatively.\n\
1416 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1417 version and, in case of successful check, to generate that speculative\n\
1418 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1419 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1420 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1421 the generated speculative pattern.",
1422 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1424 /* The following member value is a pointer to a function called
1425 by the insn scheduler. It should return true if the check instruction
1426 passed as the parameter needs a recovery block. */
1429 "This hook is called by the insn scheduler during generation of recovery code\n\
1430 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1431 instruction should branch to recovery code, or @code{false} otherwise.",
1432 bool, (unsigned int dep_status), NULL)
1434 /* The following member value is a pointer to a function called
1435 by the insn scheduler. It should return a pattern for the check
1437 The first parameter is a speculative instruction, the second parameter
1438 is the label of the corresponding recovery block (or null, if it is a
1439 simple check). The third parameter is the kind of speculation that
1440 is being performed. */
1443 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1444 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1445 speculative instruction for which the check should be generated.\n\
1446 @var{label} is either a label of a basic block, where recovery code should\n\
1447 be emitted, or a null pointer, when requested check doesn't branch to\n\
1448 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1449 a pattern for a branchy check corresponding to a simple check denoted by\n\
1450 @var{insn} should be generated. In this case @var{label} can't be null.",
1451 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1453 /* The following member value is a pointer to a function that provides
1454 information about the speculation capabilities of the target.
1455 The parameter is a pointer to spec_info variable. */
1458 "This hook is used by the insn scheduler to find out what features should be\n\
1460 The structure *@var{spec_info} should be filled in by the target.\n\
1461 The structure describes speculation types that can be used in the scheduler.",
1462 void, (struct spec_info_def *spec_info), NULL)
1466 "Return speculation types of instruction @var{insn}.",
1467 unsigned int, (rtx_insn *insn), NULL)
1470 (get_insn_checked_ds,
1471 "Return speculation types that are checked for instruction @var{insn}",
1472 unsigned int, (rtx_insn *insn), NULL)
1476 "Return bool if rtx scanning should just skip current layer and\
1477 advance to the inner rtxes.",
1478 bool, (const_rtx x), NULL)
1480 /* The following member value is a pointer to a function that provides
1481 information about the target resource-based lower bound which is
1482 used by the swing modulo scheduler. The parameter is a pointer
1486 "This hook is called by the swing modulo scheduler to calculate a\n\
1487 resource-based lower bound which is based on the resources available in\n\
1488 the machine and the resources required by each instruction. The target\n\
1489 backend can use @var{g} to calculate such bound. A very simple lower\n\
1490 bound will be used in case this hook is not implemented: the total number\n\
1491 of instructions divided by the issue rate.",
1492 int, (struct ddg *g), NULL)
1494 /* The following member value is a function that initializes dispatch
1495 schedling and adds instructions to dispatch window according to its
1499 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1500 in its second parameter.",
1501 void, (rtx_insn *insn, int x),
1502 hook_void_rtx_insn_int)
1504 /* The following member value is a a function that returns true is
1505 dispatch schedling is supported in hardware and condition passed
1506 as the second parameter is true. */
1509 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1510 is supported in hardware and the condition specified in the parameter is true.",
1511 bool, (rtx_insn *insn, int x),
1512 hook_bool_rtx_insn_int_false)
1516 "True if the processor has an exposed pipeline, which means that not just\n\
1517 the order of instructions is important for correctness when scheduling, but\n\
1518 also the latencies of operations.",
1521 /* The following member value is a function that returns number
1522 of operations reassociator should try to put in parallel for
1523 statements of the given type. By default 1 is used. */
1525 (reassociation_width,
1526 "This hook is called by tree reassociator to determine a level of\n\
1527 parallelism required in output calculations chain.",
1528 int, (unsigned int opc, machine_mode mode),
1529 hook_int_uint_mode_1)
1531 /* The following member value is a function that returns priority for
1532 fusion of each instruction via pointer parameters. */
1535 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1536 priorities for each instruction passed in by parameter. The priorities\n\
1537 are returned via pointer parameters.\n\
1539 @var{insn} is the instruction whose priorities need to be calculated.\n\
1540 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1541 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1542 fusion priority should be calculated and returned.\n\
1543 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1544 should be calculated and returned.\n\
1546 Same @var{fusion_pri} should be returned for instructions which should\n\
1547 be scheduled together. Different @var{pri} should be returned for\n\
1548 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1549 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1550 scheduled according to the two priorities. All priorities calculated\n\
1551 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1552 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1553 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1556 Given below example:\n\
1565 ldr r16, [r2, 12]\n\
1567 @end smallexample\n\
1569 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1570 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1571 loads are actually next to each other in instruction flow. That's where\n\
1572 this scheduling fusion pass works. This hook calculates priority for each\n\
1573 instruction based on its fustion type, like:\n\
1576 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1577 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1578 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1579 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1580 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1581 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1582 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1583 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1584 @end smallexample\n\
1586 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1587 to the priorities. As a result, instructions of same fusion type will be\n\
1588 pushed together in instruction flow, like:\n\
1594 ldr r16, [r2, 12]\n\
1599 @end smallexample\n\
1601 Now peephole2 pass can simply merge the two pairs of loads.\n\
1603 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1604 work, it is only enabled by default when peephole2 is in effect.\n\
1606 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1607 the hook implementation for how different fusion types are supported.",
1608 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1610 HOOK_VECTOR_END (sched)
1612 /* Functions relating to OpenMP and Cilk Plus SIMD clones. */
1614 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1615 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1618 (compute_vecsize_and_simdlen,
1619 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1620 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1621 @var{simdlen} field if it was previously 0.\n\
1622 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1623 or number of @var{vecsize_mangle} variants that should be emitted.",
1624 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1628 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1629 to SIMD clone @var{node} if needed.",
1630 void, (struct cgraph_node *), NULL)
1634 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1635 in vectorized loops in current function, or non-negative number if it is\n\
1636 usable. In that case, the smaller the number is, the more desirable it is\n\
1638 int, (struct cgraph_node *), NULL)
1640 HOOK_VECTOR_END (simd_clone)
1642 /* Functions relating to openacc. */
1644 #define HOOK_PREFIX "TARGET_GOACC_"
1645 HOOK_VECTOR (TARGET_GOACC, goacc)
1649 "This hook should check the launch dimensions provided for an OpenACC\n\
1650 compute region, or routine. Defaulted values are represented as -1\n\
1651 and non-constant values as 0. The @var{fn_level} is negative for the\n\
1652 function corresponding to the compute region. For a routine is is the\n\
1653 outermost level at which partitioned execution may be spawned. It\n\
1654 should fill in anything that needs to default to non-unity and verify\n\
1655 non-defaults. Diagnostics should be issued as appropriate. Return\n\
1656 true, if changes have been made. You must override this hook to\n\
1657 provide dimensions larger than 1.",
1658 bool, (tree decl, int *dims, int fn_level),
1659 default_goacc_validate_dims)
1663 "This hook should return the maximum size of a particular dimension,\n\
1664 or zero if unbounded.",
1666 default_goacc_dim_limit)
1670 "This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1671 function calls to target-specific gimple, or indicate whether they\n\
1672 should be retained. It is executed during the oacc_device_lower pass.\n\
1673 It should return true, if the call should be retained. It should\n\
1674 return false, if it is to be deleted (either because target-specific\n\
1675 gimple has been inserted before it, or there is no need for it).\n\
1676 The default hook returns false, if there are no RTL expanders for them.",
1677 bool, (gcall *call, const int *dims, bool is_fork),
1678 default_goacc_fork_join)
1682 "This hook is used by the oacc_transform pass to expand calls to the\n\
1683 @var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1684 instructions. @var{call} is gimple statement containing the call to\n\
1685 the function. This hook removes statement @var{call} after the\n\
1686 expanded sequence has been inserted. This hook is also responsible\n\
1687 for allocating any storage for reductions when necessary.",
1688 void, (gcall *call),
1689 default_goacc_reduction)
1691 HOOK_VECTOR_END (goacc)
1693 /* Functions relating to vectorization. */
1695 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1696 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1698 /* The following member value is a pointer to a function called
1699 by the vectorizer, and return the decl of the target builtin
1702 (builtin_mask_for_load,
1703 "This hook should return the DECL of a function @var{f} that given an\n\
1704 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1705 used to extract from two vectors the relevant data that resides in\n\
1706 @var{addr} in case @var{addr} is not properly aligned.\n\
1708 The autovectorizer, when vectorizing a load operation from an address\n\
1709 @var{addr} that may be unaligned, will generate two vector loads from\n\
1710 the two aligned addresses around @var{addr}. It then generates a\n\
1711 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1712 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1713 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1714 the third argument, @var{OFF}, defines how the data will be extracted\n\
1715 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1716 @var{v2}; otherwise, the returned vector is composed from the last\n\
1717 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1718 @var{OFF} elements of @var{v2}.\n\
1720 If this hook is defined, the autovectorizer will generate a call\n\
1721 to @var{f} (using the DECL tree that this hook returns) and will\n\
1722 use the return value of @var{f} as the argument @var{OFF} to\n\
1723 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1724 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1726 If this hook is not defined, then @var{addr} will be used as\n\
1727 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1728 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1731 /* Returns a code for builtin that realizes vectorized version of
1732 function, or NULL_TREE if not available. */
1734 (builtin_vectorized_function,
1735 "This hook should return the decl of a function that implements the\n\
1736 vectorized variant of the builtin function with builtin function code\n\
1737 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1738 The value of @var{fndecl} is the builtin function declaration. The\n\
1739 return type of the vectorized function shall be of vector type\n\
1740 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1741 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1742 default_builtin_vectorized_function)
1744 /* Returns a function declaration for a builtin that realizes the
1745 vector conversion, or NULL_TREE if not available. */
1747 (builtin_conversion,
1748 "This hook should return the DECL of a function that implements conversion of the\n\
1749 input vector of type @var{src_type} to type @var{dest_type}.\n\
1750 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1751 specifies how the conversion is to be applied\n\
1752 (truncation, rounding, etc.).\n\
1754 If this hook is defined, the autovectorizer will use the\n\
1755 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1756 conversion. Otherwise, it will return @code{NULL_TREE}.",
1757 tree, (unsigned code, tree dest_type, tree src_type),
1758 default_builtin_vectorized_conversion)
1760 /* Cost of different vector/scalar statements in vectorization cost
1761 model. In case of misaligned vector loads and stores the cost depends
1762 on the data type and misalignment value. */
1764 (builtin_vectorization_cost,
1765 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1766 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1767 misalignment value (@var{misalign}).",
1768 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1769 default_builtin_vectorization_cost)
1771 /* Return true if vector alignment is reachable (by peeling N
1772 iterations) for the given type. */
1774 (vector_alignment_reachable,
1775 "Return true if vector alignment is reachable (by peeling N iterations) for the given type.",
1776 bool, (const_tree type, bool is_packed),
1777 default_builtin_vector_alignment_reachable)
1779 /* Return true if a vector created for vec_perm_const is valid.
1780 A NULL indicates that all constants are valid permutations. */
1783 "Return true if a vector created for @code{vec_perm_const} is valid.",
1784 bool, (machine_mode, const unsigned char *sel),
1787 /* Return true if the target supports misaligned store/load of a
1788 specific factor denoted in the third parameter. The last parameter
1789 is true if the access is defined in a packed struct. */
1791 (support_vector_misalignment,
1792 "This hook should return true if the target supports misaligned vector\n\
1793 store/load of a specific factor denoted in the @var{misalignment}\n\
1794 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1795 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1796 parameter is true if the memory access is defined in a packed struct.",
1798 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1799 default_builtin_support_vector_misalignment)
1801 /* Return the builtin decl needed to load a vector of TYPE. */
1804 "This hook should return the built-in decl needed to load a vector of the "
1805 "given type within a transaction.",
1808 default_builtin_tm_load_store)
1810 /* Return the builtin decl needed to store a vector of TYPE. */
1813 "This hook should return the built-in decl needed to store a vector of the "
1814 "given type within a transaction.",
1817 default_builtin_tm_load_store)
1819 /* Returns the preferred mode for SIMD operations for the specified
1822 (preferred_simd_mode,
1823 "This hook should return the preferred mode for vectorizing scalar\n\
1824 mode @var{mode}. The default is\n\
1825 equal to @code{word_mode}, because the vectorizer can do some\n\
1826 transformations even in absence of specialized @acronym{SIMD} hardware.",
1828 (machine_mode mode),
1829 default_preferred_simd_mode)
1831 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1832 after processing the preferred one derived from preferred_simd_mode. */
1834 (autovectorize_vector_sizes,
1835 "This hook should return a mask of sizes that should be iterated over\n\
1836 after trying to autovectorize using the vector size derived from the\n\
1837 mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1838 The default is zero which means to not iterate over other vector sizes.",
1841 default_autovectorize_vector_sizes)
1843 /* Function to get a target mode for a vector mask. */
1846 "This hook returns mode to be used for a mask to be used for a vector\n\
1847 of specified @var{length} with @var{nunits} elements. By default an integer\n\
1848 vector mode of a proper size is returned.",
1850 (unsigned nunits, unsigned length),
1851 default_get_mask_mode)
1853 /* Target builtin that implements vector gather operation. */
1856 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1857 is the vector type of the load and @var{index_type} is scalar type of\n\
1858 the index, scaled by @var{scale}.\n\
1859 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1862 (const_tree mem_vectype, const_tree index_type, int scale),
1865 /* Target builtin that implements vector scatter operation. */
1868 "Target builtin that implements vector scatter operation. @var{vectype}\n\
1869 is the vector type of the store and @var{index_type} is scalar type of\n\
1870 the index, scaled by @var{scale}.\n\
1871 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
1874 (const_tree vectype, const_tree index_type, int scale),
1877 /* Target function to initialize the cost model for a loop or block. */
1880 "This hook should initialize target-specific data structures in preparation "
1881 "for modeling the costs of vectorizing a loop or basic block. The default "
1882 "allocates three unsigned integers for accumulating costs for the prologue, "
1883 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1884 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1885 "is being vectorized.",
1887 (struct loop *loop_info),
1890 /* Target function to record N statements of the given kind using the
1891 given vector type within the cost model data for the current loop or
1895 "This hook should update the target-specific @var{data} in response to "
1896 "adding @var{count} copies of the given @var{kind} of statement to a "
1897 "loop or basic block. The default adds the builtin vectorizer cost for "
1898 "the copies of the statement to the accumulator specified by @var{where}, "
1899 "(the prologue, body, or epilogue) and returns the amount added. The "
1900 "return value should be viewed as a tentative cost that may later be "
1903 (void *data, int count, enum vect_cost_for_stmt kind,
1904 struct _stmt_vec_info *stmt_info, int misalign,
1905 enum vect_cost_model_location where),
1906 default_add_stmt_cost)
1908 /* Target function to calculate the total cost of the current vectorized
1912 "This hook should complete calculations of the cost of vectorizing a loop "
1913 "or basic block based on @var{data}, and return the prologue, body, and "
1914 "epilogue costs as unsigned integers. The default returns the value of "
1915 "the three accumulators.",
1917 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1918 unsigned *epilogue_cost),
1919 default_finish_cost)
1921 /* Function to delete target-specific cost modeling data. */
1924 "This hook should release @var{data} and any related data structures "
1925 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1929 default_destroy_cost_data)
1931 HOOK_VECTOR_END (vectorize)
1934 #define HOOK_PREFIX "TARGET_"
1937 (record_offload_symbol,
1938 "Used when offloaded functions are seen in the compilation unit and no named\n\
1939 sections are available. It is called once for each symbol that must be\n\
1940 recorded in the offload function and variable table.",
1945 (absolute_biggest_alignment,
1946 "If defined, this target hook specifies the absolute biggest alignment\n\
1947 that a type or variable can have on this machine, otherwise,\n\
1948 @code{BIGGEST_ALIGNMENT} is used.",
1949 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
1951 /* Allow target specific overriding of option settings after options have
1952 been changed by an attribute or pragma or when it is reset at the
1953 end of the code affected by an attribute or pragma. */
1955 (override_options_after_change,
1956 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
1957 but is called when the optimize level is changed via an attribute or\n\
1958 pragma or when it is reset at the end of the code affected by the\n\
1959 attribute or pragma. It is not called at the beginning of compilation\n\
1960 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
1961 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
1962 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
1968 "Used when writing out the list of options into an LTO file. It should\n\
1969 translate any relevant target-specific options (such as the ABI in use)\n\
1970 into one of the @option{-foffload} options that exist as a common interface\n\
1971 to express such options. It should return a string containing these options,\n\
1972 separated by spaces, which the caller will free.\n",
1973 char *, (void), hook_charptr_void_null)
1976 (eh_return_filter_mode,
1977 "Return machine mode for filter value.",
1978 machine_mode, (void),
1979 default_eh_return_filter_mode)
1981 /* Return machine mode for libgcc expanded cmp instructions. */
1983 (libgcc_cmp_return_mode,
1984 "This target hook should return the mode to be used for the return value\n\
1985 of compare instructions expanded to libgcc calls. If not defined\n\
1986 @code{word_mode} is returned which is the right choice for a majority of\n\
1988 machine_mode, (void),
1989 default_libgcc_cmp_return_mode)
1991 /* Return machine mode for libgcc expanded shift instructions. */
1993 (libgcc_shift_count_mode,
1994 "This target hook should return the mode to be used for the shift count operand\n\
1995 of shift instructions expanded to libgcc calls. If not defined\n\
1996 @code{word_mode} is returned which is the right choice for a majority of\n\
1998 machine_mode, (void),
1999 default_libgcc_shift_count_mode)
2001 /* Return machine mode to be used for _Unwind_Word type. */
2004 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2005 The default is to use @code{word_mode}.",
2006 machine_mode, (void),
2007 default_unwind_word_mode)
2009 /* Given two decls, merge their attributes and return the result. */
2011 (merge_decl_attributes,
2012 "Define this target hook if the merging of decl attributes needs special\n\
2013 handling. If defined, the result is a list of the combined\n\
2014 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2015 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2016 when this is needed are when one attribute overrides another, or when an\n\
2017 attribute is nullified by a subsequent definition. This function may\n\
2018 call @code{merge_attributes} to handle machine-independent merging.\n\
2020 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2021 If the only target-specific handling you require is @samp{dllimport}\n\
2022 for Microsoft Windows targets, you should define the macro\n\
2023 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2024 will then define a function called\n\
2025 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2026 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2027 add @code{handle_dll_attribute} in the attribute table for your port\n\
2028 to perform initial processing of the @samp{dllimport} and\n\
2029 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2030 @file{i386/i386.c}, for example.",
2031 tree, (tree olddecl, tree newdecl),
2032 merge_decl_attributes)
2034 /* Given two types, merge their attributes and return the result. */
2036 (merge_type_attributes,
2037 "Define this target hook if the merging of type attributes needs special\n\
2038 handling. If defined, the result is a list of the combined\n\
2039 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2040 that @code{comptypes} has already been called and returned 1. This\n\
2041 function may call @code{merge_attributes} to handle machine-independent\n\
2043 tree, (tree type1, tree type2),
2044 merge_type_attributes)
2046 /* Table of machine attributes and functions to handle them.
2050 "If defined, this target hook points to an array of @samp{struct\n\
2051 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2052 specific attributes for this target and some of the restrictions on the\n\
2053 entities to which these attributes are applied and the arguments they\n\
2055 const struct attribute_spec *, NULL)
2057 /* Return true iff attribute NAME expects a plain identifier as its first
2060 (attribute_takes_identifier_p,
2061 "If defined, this target hook is a function which returns true if the\n\
2062 machine-specific attribute named @var{name} expects an identifier\n\
2063 given as its first argument to be passed on as a plain identifier, not\n\
2064 subjected to name lookup. If this is not defined, the default is\n\
2065 false for all machine-specific attributes.",
2066 bool, (const_tree name),
2067 hook_bool_const_tree_false)
2069 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2070 one if they are compatible and two if they are nearly compatible
2071 (which causes a warning to be generated). */
2073 (comp_type_attributes,
2074 "If defined, this target hook is a function which returns zero if the attributes on\n\
2075 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2076 and two if they are nearly compatible (which causes a warning to be\n\
2077 generated). If this is not defined, machine-specific attributes are\n\
2078 supposed always to be compatible.",
2079 int, (const_tree type1, const_tree type2),
2080 hook_int_const_tree_const_tree_1)
2082 /* Assign default attributes to the newly defined TYPE. */
2084 (set_default_type_attributes,
2085 "If defined, this target hook is a function which assigns default attributes to\n\
2086 the newly defined @var{type}.",
2090 /* Insert attributes on the newly created DECL. */
2093 "Define this target hook if you want to be able to add attributes to a decl\n\
2094 when it is being created. This is normally useful for back ends which\n\
2095 wish to implement a pragma by using the attributes which correspond to\n\
2096 the pragma's effect. The @var{node} argument is the decl which is being\n\
2097 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2098 for this decl. The list itself should not be modified, since it may be\n\
2099 shared with other decls, but attributes may be chained on the head of\n\
2100 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2101 attributes, or a copy of the list may be made if further changes are\n\
2103 void, (tree node, tree *attr_ptr),
2104 hook_void_tree_treeptr)
2106 /* Return true if FNDECL (which has at least one machine attribute)
2107 can be inlined despite its machine attributes, false otherwise. */
2109 (function_attribute_inlinable_p,
2110 "@cindex inlining\n\
2111 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2112 into the current function, despite its having target-specific\n\
2113 attributes, @code{false} otherwise. By default, if a function has a\n\
2114 target specific attribute attached to it, it will not be inlined.",
2115 bool, (const_tree fndecl),
2116 hook_bool_const_tree_false)
2118 /* Return true if bitfields in RECORD_TYPE should follow the
2119 Microsoft Visual C++ bitfield layout rules. */
2121 (ms_bitfield_layout_p,
2122 "This target hook returns @code{true} if bit-fields in the given\n\
2123 @var{record_type} are to be laid out following the rules of Microsoft\n\
2124 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2125 unit with the previous bit-field if their underlying types have\n\
2126 different sizes, and the bit-field will be aligned to the highest\n\
2127 alignment of the underlying types of itself and of the previous\n\
2128 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2129 the whole enclosing structure, even if it is unnamed; except that\n\
2130 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2131 another bit-field of nonzero size. If this hook returns @code{true},\n\
2132 other macros that control bit-field layout are ignored.\n\
2134 When a bit-field is inserted into a packed record, the whole size\n\
2135 of the underlying type is used by one or more same-size adjacent\n\
2136 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2137 and any additional adjacent long bit-fields are packed into the same\n\
2138 chunk of 32 bits. However, if the size changes, a new field of that\n\
2139 size is allocated). In an unpacked record, this is the same as using\n\
2140 alignment, but not equivalent when packing.\n\
2142 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2143 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2144 used on a single field when MS bit-fields are in use, it will take\n\
2145 precedence for that field, but the alignment of the rest of the structure\n\
2146 may affect its placement.",
2147 bool, (const_tree record_type),
2148 hook_bool_const_tree_false)
2150 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2151 target-independent code like the front ends, need performance testing
2152 before switching completely to the target hook. */
2157 targhook_words_big_endian)
2159 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2161 (float_words_big_endian,
2164 targhook_float_words_big_endian)
2167 (float_exceptions_rounding_supported_p,
2168 "Returns true if the target supports IEEE 754 floating-point exceptions\
2169 and rounding modes, false otherwise. This is intended to relate to the\
2170 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2171 By default, returns true if the @code{adddf3} instruction pattern is\
2172 available and false otherwise, on the assumption that hardware floating\
2173 point supports exceptions and rounding modes but software floating point\
2176 default_float_exceptions_rounding_supported_p)
2178 /* True if the target supports decimal floating point. */
2180 (decimal_float_supported_p,
2181 "Returns true if the target supports decimal floating point.",
2183 default_decimal_float_supported_p)
2185 /* True if the target supports fixed-point. */
2187 (fixed_point_supported_p,
2188 "Returns true if the target supports fixed-point arithmetic.",
2190 default_fixed_point_supported_p)
2192 /* Return true if anonymous bitfields affect structure alignment. */
2194 (align_anon_bitfield,
2195 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2196 whether unnamed bitfields affect the alignment of the containing\n\
2197 structure. The hook should return true if the structure should inherit\n\
2198 the alignment requirements of an unnamed bitfield's type.",
2200 hook_bool_void_false)
2202 /* Return true if volatile bitfields should use the narrowest type possible.
2203 Return false if they should use the container type. */
2205 (narrow_volatile_bitfield,
2206 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2207 should use the narrowest mode possible. It should return @code{false} if\n\
2208 these accesses should use the bitfield container type.\n\
2210 The default is @code{false}.",
2212 hook_bool_void_false)
2214 /* Set up target-specific built-in functions. */
2217 "Define this hook if you have any machine-specific built-in functions\n\
2218 that need to be defined. It should be a function that performs the\n\
2221 Machine specific built-in functions can be useful to expand special machine\n\
2222 instructions that would otherwise not normally be generated because\n\
2223 they have no equivalent in the source language (for example, SIMD vector\n\
2224 instructions or prefetch instructions).\n\
2226 To create a built-in function, call the function\n\
2227 @code{lang_hooks.builtin_function}\n\
2228 which is defined by the language front end. You can use any type nodes set\n\
2229 up by @code{build_common_tree_nodes};\n\
2230 only language front ends that use those two functions will call\n\
2231 @samp{TARGET_INIT_BUILTINS}.",
2235 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2236 built-in function decl for CODE.
2237 Return NULL if that is not possible. Return error_mark_node if CODE
2238 is outside of the range of valid target builtin function codes. */
2241 "Define this hook if you have any machine-specific built-in functions\n\
2242 that need to be defined. It should be a function that returns the\n\
2243 builtin function declaration for the builtin function code @var{code}.\n\
2244 If there is no such builtin and it cannot be initialized at this time\n\
2245 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2246 If @var{code} is out of range the function should return\n\
2247 @code{error_mark_node}.",
2248 tree, (unsigned code, bool initialize_p), NULL)
2250 /* Expand a target-specific builtin. */
2254 Expand a call to a machine specific built-in function that was set up by\n\
2255 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2256 function call; the result should go to @var{target} if that is\n\
2257 convenient, and have mode @var{mode} if that is convenient.\n\
2258 @var{subtarget} may be used as the target for computing one of\n\
2259 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2260 ignored. This function should return the result of the call to the\n\
2261 built-in function.",
2263 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2264 default_expand_builtin)
2267 (builtin_chkp_function,
2268 "This hook allows target to redefine built-in functions used by\n\
2269 Pointer Bounds Checker for code instrumentation. Hook should return\n\
2270 fndecl of function implementing generic builtin whose code is\n\
2271 passed in @var{fcode}. Currently following built-in functions are\n\
2272 obtained using this hook:\n\
2273 @deftypefn {Built-in Function} __bounds_type __chkp_bndmk (const void *@var{lb}, size_t @var{size})\n\
2274 Function code - BUILT_IN_CHKP_BNDMK. This built-in function is used\n\
2275 by Pointer Bounds Checker to create bound values. @var{lb} holds low\n\
2276 bound of the resulting bounds. @var{size} holds size of created bounds.\n\
2279 @deftypefn {Built-in Function} void __chkp_bndstx (const void *@var{ptr}, __bounds_type @var{b}, const void **@var{loc})\n\
2280 Function code - @code{BUILT_IN_CHKP_BNDSTX}. This built-in function is used\n\
2281 by Pointer Bounds Checker to store bounds @var{b} for pointer @var{ptr}\n\
2282 when @var{ptr} is stored by address @var{loc}.\n\
2285 @deftypefn {Built-in Function} __bounds_type __chkp_bndldx (const void **@var{loc}, const void *@var{ptr})\n\
2286 Function code - @code{BUILT_IN_CHKP_BNDLDX}. This built-in function is used\n\
2287 by Pointer Bounds Checker to get bounds of pointer @var{ptr} loaded by\n\
2288 address @var{loc}.\n\
2291 @deftypefn {Built-in Function} void __chkp_bndcl (const void *@var{ptr}, __bounds_type @var{b})\n\
2292 Function code - @code{BUILT_IN_CHKP_BNDCL}. This built-in function is used\n\
2293 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2294 lower bound of bounds @var{b}.\n\
2297 @deftypefn {Built-in Function} void __chkp_bndcu (const void *@var{ptr}, __bounds_type @var{b})\n\
2298 Function code - @code{BUILT_IN_CHKP_BNDCU}. This built-in function is used\n\
2299 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2300 upper bound of bounds @var{b}.\n\
2303 @deftypefn {Built-in Function} __bounds_type __chkp_bndret (void *@var{ptr})\n\
2304 Function code - @code{BUILT_IN_CHKP_BNDRET}. This built-in function is used\n\
2305 by Pointer Bounds Checker to obtain bounds returned by a call statement.\n\
2306 @var{ptr} passed to built-in is @code{SSA_NAME} returned by the call.\n\
2309 @deftypefn {Built-in Function} __bounds_type __chkp_intersect (__bounds_type @var{b1}, __bounds_type @var{b2})\n\
2310 Function code - @code{BUILT_IN_CHKP_INTERSECT}. This built-in function\n\
2311 returns intersection of bounds @var{b1} and @var{b2}.\n\
2314 @deftypefn {Built-in Function} __bounds_type __chkp_narrow (const void *@var{ptr}, __bounds_type @var{b}, size_t @var{s})\n\
2315 Function code - @code{BUILT_IN_CHKP_NARROW}. This built-in function\n\
2316 returns intersection of bounds @var{b} and\n\
2317 [@var{ptr}, @var{ptr} + @var{s} - @code{1}].\n\
2320 @deftypefn {Built-in Function} size_t __chkp_sizeof (const void *@var{ptr})\n\
2321 Function code - @code{BUILT_IN_CHKP_SIZEOF}. This built-in function\n\
2322 returns size of object referenced by @var{ptr}. @var{ptr} is always\n\
2323 @code{ADDR_EXPR} of @code{VAR_DECL}. This built-in is used by\n\
2324 Pointer Bounds Checker when bounds of object cannot be computed statically\n\
2325 (e.g. object has incomplete type).\n\
2328 @deftypefn {Built-in Function} const void *__chkp_extract_lower (__bounds_type @var{b})\n\
2329 Function code - @code{BUILT_IN_CHKP_EXTRACT_LOWER}. This built-in function\n\
2330 returns lower bound of bounds @var{b}.\n\
2333 @deftypefn {Built-in Function} const void *__chkp_extract_upper (__bounds_type @var{b})\n\
2334 Function code - @code{BUILT_IN_CHKP_EXTRACT_UPPER}. This built-in function\n\
2335 returns upper bound of bounds @var{b}.\n\
2337 tree, (unsigned fcode),
2338 default_builtin_chkp_function)
2342 "Return type to be used for bounds",
2344 default_chkp_bound_type)
2348 "Return mode to be used for bounds.",
2349 enum machine_mode, (void),
2350 default_chkp_bound_mode)
2353 (chkp_make_bounds_constant,
2354 "Return constant used to statically initialize constant bounds\n\
2355 with specified lower bound @var{lb} and upper bounds @var{ub}.",
2356 tree, (HOST_WIDE_INT lb, HOST_WIDE_INT ub),
2357 default_chkp_make_bounds_constant)
2360 (chkp_initialize_bounds,
2361 "Generate a list of statements @var{stmts} to initialize pointer\n\
2362 bounds variable @var{var} with bounds @var{lb} and @var{ub}. Return\n\
2363 the number of generated statements.",
2364 int, (tree var, tree lb, tree ub, tree *stmts),
2365 default_chkp_initialize_bounds)
2367 /* Select a replacement for a target-specific builtin. This is done
2368 *before* regular type checking, and so allows the target to
2369 implement a crude form of function overloading. The result is a
2370 complete expression that implements the operation. PARAMS really
2371 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2373 (resolve_overloaded_builtin,
2374 "Select a replacement for a machine specific built-in function that\n\
2375 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2376 @emph{before} regular type checking, and so allows the target to\n\
2377 implement a crude form of function overloading. @var{fndecl} is the\n\
2378 declaration of the built-in function. @var{arglist} is the list of\n\
2379 arguments passed to the built-in function. The result is a\n\
2380 complete expression that implements the operation, usually\n\
2381 another @code{CALL_EXPR}.\n\
2382 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2383 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2385 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2389 "Fold a call to a machine specific built-in function that was set up by\n\
2390 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2391 built-in function. @var{n_args} is the number of arguments passed to\n\
2392 the function; the arguments themselves are pointed to by @var{argp}.\n\
2393 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2394 containing a simplified expression for the call's result. If\n\
2395 @var{ignore} is true the value will be ignored.",
2396 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2397 hook_tree_tree_int_treep_bool_null)
2399 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2401 (gimple_fold_builtin,
2402 "Fold a call to a machine specific built-in function that was set up\n\
2403 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2404 statement holding the function call. Returns true if any change\n\
2405 was made to the GIMPLE stream.",
2406 bool, (gimple_stmt_iterator *gsi),
2407 hook_bool_gsiptr_false)
2409 /* Target hook is used to compare the target attributes in two functions to
2410 determine which function's features get higher priority. This is used
2411 during function multi-versioning to figure out the order in which two
2412 versions must be dispatched. A function version with a higher priority
2413 is checked for dispatching earlier. DECL1 and DECL2 are
2414 the two function decls that will be compared. It returns positive value
2415 if DECL1 is higher priority, negative value if DECL2 is higher priority
2416 and 0 if they are the same. */
2418 (compare_version_priority,
2419 "This hook is used to compare the target attributes in two functions to\n\
2420 determine which function's features get higher priority. This is used\n\
2421 during function multi-versioning to figure out the order in which two\n\
2422 versions must be dispatched. A function version with a higher priority\n\
2423 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2424 the two function decls that will be compared.",
2425 int, (tree decl1, tree decl2), NULL)
2427 /* Target hook is used to generate the dispatcher logic to invoke the right
2428 function version at run-time for a given set of function versions.
2429 ARG points to the callgraph node of the dispatcher function whose body
2430 must be generated. */
2432 (generate_version_dispatcher_body,
2433 "This hook is used to generate the dispatcher logic to invoke the right\n\
2434 function version at run-time for a given set of function versions.\n\
2435 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2436 body must be generated.",
2437 tree, (void *arg), NULL)
2439 /* Target hook is used to get the dispatcher function for a set of function
2440 versions. The dispatcher function is called to invoke the right function
2441 version at run-time. DECL is one version from a set of semantically
2442 identical versions. */
2444 (get_function_versions_dispatcher,
2445 "This hook is used to get the dispatcher function for a set of function\n\
2446 versions. The dispatcher function is called to invoke the right function\n\
2447 version at run-time. @var{decl} is one version from a set of semantically\n\
2448 identical versions.",
2449 tree, (void *decl), NULL)
2451 /* Returns a code for a target-specific builtin that implements
2452 reciprocal of the function, or NULL_TREE if not available. */
2454 (builtin_reciprocal,
2455 "This hook should return the DECL of a function that implements reciprocal of\n\
2456 the builtin function with builtin function code @var{fn}, or\n\
2457 @code{NULL_TREE} if such a function is not available. @var{md_fn} is true\n\
2458 when @var{fn} is a code of a machine-dependent builtin function. When\n\
2459 @var{sqrt} is true, additional optimizations that apply only to the reciprocal\n\
2460 of a square root function are performed, and only reciprocals of @code{sqrt}\n\
2461 function are valid.",
2462 tree, (unsigned fn, bool md_fn, bool sqrt),
2463 default_builtin_reciprocal)
2465 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2466 string containing the C++ mangling for TYPE. In all other cases, return
2470 "If your target defines any fundamental types, or any types your target\n\
2471 uses should be mangled differently from the default, define this hook\n\
2472 to return the appropriate encoding for these types as part of a C++\n\
2473 mangled name. The @var{type} argument is the tree structure representing\n\
2474 the type to be mangled. The hook may be applied to trees which are\n\
2475 not target-specific fundamental types; it should return @code{NULL}\n\
2476 for all such types, as well as arguments it does not recognize. If the\n\
2477 return value is not @code{NULL}, it must point to a statically-allocated\n\
2480 Target-specific fundamental types might be new fundamental types or\n\
2481 qualified versions of ordinary fundamental types. Encode new\n\
2482 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2483 is the name used for the type in source code, and @var{n} is the\n\
2484 length of @var{name} in decimal. Encode qualified versions of\n\
2485 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2486 @var{name} is the name used for the type qualifier in source code,\n\
2487 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2488 code used to represent the unqualified version of this type. (See\n\
2489 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2490 codes.) In both cases the spaces are for clarity; do not include any\n\
2491 spaces in your string.\n\
2493 This hook is applied to types prior to typedef resolution. If the mangled\n\
2494 name for a particular type depends only on that type's main variant, you\n\
2495 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2498 The default version of this hook always returns @code{NULL}, which is\n\
2499 appropriate for a target that does not define any new fundamental\n\
2501 const char *, (const_tree type),
2502 hook_constcharptr_const_tree_null)
2504 /* Make any adjustments to libfunc names needed for this target. */
2507 "This hook should declare additional library routines or rename\n\
2508 existing ones, using the functions @code{set_optab_libfunc} and\n\
2509 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2510 @code{init_optabs} calls this macro after initializing all the normal\n\
2511 library routines.\n\
2513 The default is to do nothing. Most ports don't need to define this hook.",
2517 /* Add a __gnu_ prefix to library functions rather than just __. */
2519 (libfunc_gnu_prefix,
2520 "If false (the default), internal library routines start with two\n\
2521 underscores. If set to true, these routines start with @code{__gnu_}\n\
2522 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2523 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2524 is set to true, the @file{tm.h} file must also\n\
2525 @code{#define LIBGCC2_GNU_PREFIX}.",
2528 /* Given a decl, a section name, and whether the decl initializer
2529 has relocs, choose attributes for the section. */
2530 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2532 (section_type_flags,
2533 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2534 based on a variable or function decl, a section name, and whether or not the\n\
2535 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2536 null, in which case read-write data should be assumed.\n\
2538 The default version of this function handles choosing code vs data,\n\
2539 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2540 need to override this if your target has special flags that might be\n\
2541 set via @code{__attribute__}.",
2542 unsigned int, (tree decl, const char *name, int reloc),
2543 default_section_type_flags)
2547 "This hook determines whether a function from a class of functions\n\
2548 @var{fn_class} is present at the runtime.",
2549 bool, (enum function_class fn_class),
2550 default_libc_has_function)
2552 /* True if new jumps cannot be created, to replace existing ones or
2553 not, at the current point in the compilation. */
2555 (cannot_modify_jumps_p,
2556 "This target hook returns @code{true} past the point in which new jump\n\
2557 instructions could be created. On machines that require a register for\n\
2558 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2559 reload, so this target hook should be defined to a function such as:\n\
2563 cannot_modify_jumps_past_reload_p ()\n\
2565 return (reload_completed || reload_in_progress);\n\
2569 hook_bool_void_false)
2571 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2574 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2575 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2576 false, if it can't.\
2577 For example, on some targets, certain kinds of branches can't be made to\
2578 follow through a hot/cold partitioning.",
2579 bool, (const rtx_insn *follower, const rtx_insn *followee),
2580 hook_bool_const_rtx_insn_const_rtx_insn_true)
2582 /* Return a register class for which branch target register
2583 optimizations should be applied. */
2585 (branch_target_register_class,
2586 "This target hook returns a register class for which branch target register\n\
2587 optimizations should be applied. All registers in this class should be\n\
2588 usable interchangeably. After reload, registers in this class will be\n\
2589 re-allocated and loads will be hoisted out of loops and be subjected\n\
2590 to inter-block scheduling.",
2591 reg_class_t, (void),
2592 default_branch_target_register_class)
2594 /* Return true if branch target register optimizations should include
2595 callee-saved registers that are not already live during the current
2596 function. AFTER_PE_GEN is true if prologues and epilogues have
2597 already been generated. */
2599 (branch_target_register_callee_saved,
2600 "Branch target register optimization will by default exclude callee-saved\n\
2602 that are not already live during the current function; if this target hook\n\
2603 returns true, they will be included. The target code must than make sure\n\
2604 that all target registers in the class returned by\n\
2605 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2606 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2607 epilogues have already been generated. Note, even if you only return\n\
2608 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2609 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2610 to reserve space for caller-saved target registers.",
2611 bool, (bool after_prologue_epilogue_gen),
2612 hook_bool_bool_false)
2614 /* Return true if the target supports conditional execution. */
2616 (have_conditional_execution,
2617 "This target hook returns true if the target supports conditional execution.\n\
2618 This target hook is required only when the target has several different\n\
2619 modes and they have different conditional execution capability, such as ARM.",
2621 default_have_conditional_execution)
2625 "This function prepares to emit a comparison insn for the first compare in a\n\
2626 sequence of conditional comparisions. It returns a appropriate @code{CC}\n\
2627 for passing to @code{gen_ccmp_next} or @code{cbranch_optab}. The insns to\n\
2628 prepare the compare are saved in @var{prep_seq} and the compare insns are\n\
2629 saved in @var{gen_seq}. They will be emitted when all the compares in the\n\
2630 the conditional comparision are generated without error. @var{code} is\n\
2631 the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2632 rtx, (rtx *prep_seq, rtx *gen_seq, int code, tree op0, tree op1),
2637 "This function prepare to emit a conditional comparison within a sequence of\n\
2638 conditional comparisons. It returns a appropriate @code{CC} for passing to\n\
2639 @code{gen_ccmp_next} or @code{cbranch_optab}. The insns to prepare the\n\
2640 compare are saved in @var{prep_seq} and the compare insns are saved in\n\
2641 @var{gen_seq}. They will be emitted when all the compares in the conditional\n\
2642 comparision are generated without error. The @var{prev} expression is the\n\
2643 result of a prior call to @code{gen_ccmp_first} or @code{gen_ccmp_next}. It\n\
2644 may return @code{NULL} if the combination of @var{prev} and this comparison is\n\
2645 not supported, otherwise the result must be appropriate for passing to\n\
2646 @code{gen_ccmp_next} or @code{cbranch_optab}. @var{code} is the\n\
2647 @code{rtx_code} of the compare for @var{op0} and @var{op1}. @var{bit_code}\n\
2648 is @code{AND} or @code{IOR}, which is the op on the two compares.",
2649 rtx, (rtx *prep_seq, rtx *gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2652 /* Return a new value for loop unroll size. */
2654 (loop_unroll_adjust,
2655 "This target hook returns a new value for the number of times @var{loop}\n\
2656 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2657 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2658 the loop, which is going to be checked for unrolling. This target hook\n\
2659 is required only when the target has special constraints like maximum\n\
2660 number of memory accesses.",
2661 unsigned, (unsigned nunroll, struct loop *loop),
2664 /* True if X is a legitimate MODE-mode immediate operand. */
2666 (legitimate_constant_p,
2667 "This hook returns true if @var{x} is a legitimate constant for a\n\
2668 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2669 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2671 The default definition returns true.",
2672 bool, (machine_mode mode, rtx x),
2673 hook_bool_mode_rtx_true)
2675 /* True if the constant X cannot be placed in the constant pool. */
2677 (cannot_force_const_mem,
2678 "This hook should return true if @var{x} is of a form that cannot (or\n\
2679 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2682 The default version of this hook returns false.\n\
2684 The primary reason to define this hook is to prevent reload from\n\
2685 deciding that a non-legitimate constant would be better reloaded\n\
2686 from the constant pool instead of spilling and reloading a register\n\
2687 holding the constant. This restriction is often true of addresses\n\
2688 of TLS symbols for various targets.",
2689 bool, (machine_mode mode, rtx x),
2690 hook_bool_mode_rtx_false)
2693 (cannot_copy_insn_p,
2694 "True if the insn @var{x} cannot be duplicated.",
2695 bool, (rtx_insn *), NULL)
2697 /* True if X is considered to be commutative. */
2700 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2701 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2702 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2703 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2704 bool, (const_rtx x, int outer_code),
2705 hook_bool_const_rtx_commutative_p)
2707 /* True if ADDR is an address-expression whose effect depends
2708 on the mode of the memory reference it is used in. */
2710 (mode_dependent_address_p,
2711 "This hook returns @code{true} if memory address @var{addr} in address\n\
2712 space @var{addrspace} can have\n\
2713 different meanings depending on the machine mode of the memory\n\
2714 reference it is used for or if the address is valid for some modes\n\
2717 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2718 effects because the amount of the increment or decrement is the size\n\
2719 of the operand being addressed. Some machines have other mode-dependent\n\
2720 addresses. Many RISC machines have no mode-dependent addresses.\n\
2722 You may assume that @var{addr} is a valid address for the machine.\n\
2724 The default version of this hook returns @code{false}.",
2725 bool, (const_rtx addr, addr_space_t addrspace),
2726 default_mode_dependent_address_p)
2728 /* Given an invalid address X for a given machine mode, try machine-specific
2729 ways to make it legitimate. Return X or an invalid address on failure. */
2731 (legitimize_address,
2732 "This hook is given an invalid memory address @var{x} for an\n\
2733 operand of mode @var{mode} and should try to return a valid memory\n\
2736 @findex break_out_memory_refs\n\
2737 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2738 and @var{oldx} will be the operand that was given to that function to produce\n\
2741 The code of the hook should not alter the substructure of\n\
2742 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2743 should return the new @var{x}.\n\
2745 It is not necessary for this hook to come up with a legitimate address,\n\
2746 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2747 The compiler has standard ways of doing so in all cases. In fact, if\n\
2748 the target supports only emulated TLS, it\n\
2749 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2750 a valid way to legitimize the address. But often a machine-dependent\n\
2751 strategy can generate better code.",
2752 rtx, (rtx x, rtx oldx, machine_mode mode),
2753 default_legitimize_address)
2755 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2757 (delegitimize_address,
2758 "This hook is used to undo the possibly obfuscating effects of the\n\
2759 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2760 macros. Some backend implementations of these macros wrap symbol\n\
2761 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2762 addressing modes. This target hook allows GCC's optimizers to understand\n\
2763 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2764 into their original form.",
2766 delegitimize_mem_from_attrs)
2768 /* Given an RTX, return true if it is not ok to emit it into debug info
2771 (const_not_ok_for_debug_p,
2772 "This hook should return true if @var{x} should not be emitted into\n\
2775 hook_bool_rtx_false)
2777 /* Given an address RTX, say whether it is valid. */
2779 (legitimate_address_p,
2780 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2781 address on the target machine for a memory operand of mode @var{mode}.\n\
2783 Legitimate addresses are defined in two variants: a strict variant and a\n\
2784 non-strict one. The @var{strict} parameter chooses which variant is\n\
2785 desired by the caller.\n\
2787 The strict variant is used in the reload pass. It must be defined so\n\
2788 that any pseudo-register that has not been allocated a hard register is\n\
2789 considered a memory reference. This is because in contexts where some\n\
2790 kind of register is required, a pseudo-register with no hard register\n\
2791 must be rejected. For non-hard registers, the strict variant should look\n\
2792 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2793 register number in the array, or treat the pseudo as a memory reference\n\
2794 if the array holds @code{-1}.\n\
2796 The non-strict variant is used in other passes. It must be defined to\n\
2797 accept all pseudo-registers in every context where some kind of\n\
2798 register is required.\n\
2800 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2801 and an integer are stored inside a @code{const} RTX to mark them as\n\
2802 constant. Therefore, there is no need to recognize such sums\n\
2803 specifically as legitimate addresses. Normally you would simply\n\
2804 recognize any @code{const} as legitimate.\n\
2806 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2807 sums that are not marked with @code{const}. It assumes that a naked\n\
2808 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2809 naked constant sums as illegitimate addresses, so that none of them will\n\
2810 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2812 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2813 On some machines, whether a symbolic address is legitimate depends on\n\
2814 the section that the address refers to. On these machines, define the\n\
2815 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2816 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2817 @code{const}, you will have to look inside it to find the\n\
2818 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2821 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2822 Some ports are still using a deprecated legacy substitute for\n\
2823 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2827 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2831 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2832 address on the target machine for a memory operand of mode @var{mode}.\n\
2834 @findex REG_OK_STRICT\n\
2835 Compiler source files that want to use the strict variant of this\n\
2836 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2837 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2838 that case and the non-strict variant otherwise.\n\
2840 Using the hook is usually simpler because it limits the number of\n\
2841 files that are recompiled when changes are made.",
2842 bool, (machine_mode mode, rtx x, bool strict),
2843 default_legitimate_address_p)
2845 /* True if the given constant can be put into an object_block. */
2847 (use_blocks_for_constant_p,
2848 "This hook should return true if pool entries for constant @var{x} can\n\
2849 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2852 The default version returns false for all constants.",
2853 bool, (machine_mode mode, const_rtx x),
2854 hook_bool_mode_const_rtx_false)
2856 /* True if the given decl can be put into an object_block. */
2858 (use_blocks_for_decl_p,
2859 "This hook should return true if pool entries for @var{decl} should\n\
2860 be placed in an @code{object_block} structure.\n\
2862 The default version returns true for all decls.",
2863 bool, (const_tree decl),
2864 hook_bool_const_tree_true)
2866 /* The minimum and maximum byte offsets for anchored addresses. */
2869 "The minimum offset that should be applied to a section anchor.\n\
2870 On most targets, it should be the smallest offset that can be\n\
2871 applied to a base register while still giving a legitimate address\n\
2872 for every mode. The default value is 0.",
2877 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2878 offset that should be applied to section anchors. The default\n\
2882 /* True if section anchors can be used to access the given symbol. */
2884 (use_anchors_for_symbol_p,
2885 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2886 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2887 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2889 The default version is correct for most targets, but you might need to\n\
2890 intercept this hook to handle things like target-specific attributes\n\
2891 or target-specific sections.",
2892 bool, (const_rtx x),
2893 default_use_anchors_for_symbol_p)
2895 /* True if target supports indirect functions. */
2898 "It returns true if the target supports GNU indirect functions.\n\
2899 The support includes the assembler, linker and dynamic linker.\n\
2900 The default value of this hook is based on target's libc.",
2902 default_has_ifunc_p)
2904 /* True if it is OK to do sibling call optimization for the specified
2905 call expression EXP. DECL will be the called function, or NULL if
2906 this is an indirect call. */
2908 (function_ok_for_sibcall,
2909 "True if it is OK to do sibling call optimization for the specified\n\
2910 call expression @var{exp}. @var{decl} will be the called function,\n\
2911 or @code{NULL} if this is an indirect call.\n\
2913 It is not uncommon for limitations of calling conventions to prevent\n\
2914 tail calls to functions outside the current unit of translation, or\n\
2915 during PIC compilation. The hook is used to enforce these restrictions,\n\
2916 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2917 ``normal'' call. The criteria for successful sibling call optimization\n\
2918 may vary greatly between different architectures.",
2919 bool, (tree decl, tree exp),
2920 hook_bool_tree_tree_false)
2922 /* Establish appropriate back-end context for processing the function
2923 FNDECL. The argument might be NULL to indicate processing at top
2924 level, outside of any function scope. */
2926 (set_current_function,
2927 "The compiler invokes this hook whenever it changes its current function\n\
2928 context (@code{cfun}). You can define this function if\n\
2929 the back end needs to perform any initialization or reset actions on a\n\
2930 per-function basis. For example, it may be used to implement function\n\
2931 attributes that affect register usage or code generation patterns.\n\
2932 The argument @var{decl} is the declaration for the new function context,\n\
2933 and may be null to indicate that the compiler has left a function context\n\
2934 and is returning to processing at the top level.\n\
2935 The default hook function does nothing.\n\
2937 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2938 some parts of the back end. The hook function is not invoked in this\n\
2939 situation; you need not worry about the hook being invoked recursively,\n\
2940 or when the back end is in a partially-initialized state.\n\
2941 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2942 outside of any function scope.",
2943 void, (tree decl), hook_void_tree)
2945 /* True if EXP should be placed in a "small data" section. */
2948 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2949 The default version of this hook always returns false.",
2950 bool, (const_tree exp),
2951 hook_bool_const_tree_false)
2953 /* True if EXP names an object for which name resolution must resolve
2954 to the current executable or shared library. */
2957 "Returns true if @var{exp} names an object for which name resolution\n\
2958 rules must resolve to the current ``module'' (dynamic shared library\n\
2959 or executable image).\n\
2961 The default version of this hook implements the name resolution rules\n\
2962 for ELF, which has a looser model of global name binding than other\n\
2963 currently supported object file formats.",
2964 bool, (const_tree exp),
2965 default_binds_local_p)
2967 /* Check if profiling code is before or after prologue. */
2969 (profile_before_prologue,
2970 "It returns true if target wants profile code emitted before prologue.\n\n\
2971 The default version of this hook use the target macro\n\
2972 @code{PROFILE_BEFORE_PROLOGUE}.",
2974 default_profile_before_prologue)
2976 /* Return true if a leaf function should stay leaf even with profiling
2979 (keep_leaf_when_profiled,
2980 "This target hook returns true if the target wants the leaf flag for\
2981 the current function to stay true even if it calls mcount. This might\
2982 make sense for targets using the leaf flag only to determine whether a\
2983 stack frame needs to be generated or not and for which the call to\
2984 mcount is generated before the function prologue.",
2986 default_keep_leaf_when_profiled)
2988 /* Modify and return the identifier of a DECL's external name,
2989 originally identified by ID, as required by the target,
2990 (eg, append @nn to windows32 stdcall function names).
2991 The default is to return ID without modification. */
2993 (mangle_decl_assembler_name,
2994 "Define this hook if you need to postprocess the assembler name generated\n\
2995 by target-independent code. The @var{id} provided to this hook will be\n\
2996 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
2997 or the mangled name of the @var{decl} in C++). The return value of the\n\
2998 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
2999 your target system. The default implementation of this hook just\n\
3000 returns the @var{id} provided.",
3001 tree, (tree decl, tree id),
3002 default_mangle_decl_assembler_name)
3004 /* Do something target-specific to record properties of the DECL into
3005 the associated SYMBOL_REF. */
3007 (encode_section_info,
3008 "Define this hook if references to a symbol or a constant must be\n\
3009 treated differently depending on something about the variable or\n\
3010 function named by the symbol (such as what section it is in).\n\
3012 The hook is executed immediately after rtl has been created for\n\
3013 @var{decl}, which may be a variable or function declaration or\n\
3014 an entry in the constant pool. In either case, @var{rtl} is the\n\
3015 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3016 in this hook; that field may not have been initialized yet.\n\
3018 In the case of a constant, it is safe to assume that the rtl is\n\
3019 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3020 will also have this form, but that is not guaranteed. Global\n\
3021 register variables, for instance, will have a @code{reg} for their\n\
3022 rtl. (Normally the right thing to do with such unusual rtl is\n\
3025 The @var{new_decl_p} argument will be true if this is the first time\n\
3026 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3027 be false for subsequent invocations, which will happen for duplicate\n\
3028 declarations. Whether or not anything must be done for the duplicate\n\
3029 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3030 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3032 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3033 The usual thing for this hook to do is to record flags in the\n\
3034 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3035 Historically, the name string was modified if it was necessary to\n\
3036 encode more than one bit of information, but this practice is now\n\
3037 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3039 The default definition of this hook, @code{default_encode_section_info}\n\
3040 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
3041 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3042 before overriding it.",
3043 void, (tree decl, rtx rtl, int new_decl_p),
3044 default_encode_section_info)
3046 /* Undo the effects of encode_section_info on the symbol string. */
3048 (strip_name_encoding,
3049 "Decode @var{name} and return the real name part, sans\n\
3050 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3052 const char *, (const char *name),
3053 default_strip_name_encoding)
3055 /* If shift optabs for MODE are known to always truncate the shift count,
3056 return the mask that they apply. Return 0 otherwise. */
3058 (shift_truncation_mask,
3059 "This function describes how the standard shift patterns for @var{mode}\n\
3060 deal with shifts by negative amounts or by more than the width of the mode.\n\
3061 @xref{shift patterns}.\n\
3063 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3064 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3065 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3066 this is true for mode @var{mode}, the function should return @var{m},\n\
3067 otherwise it should return 0. A return value of 0 indicates that no\n\
3068 particular behavior is guaranteed.\n\
3070 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3071 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3072 that are generated by the named shift patterns.\n\
3074 The default implementation of this function returns\n\
3075 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3076 and 0 otherwise. This definition is always safe, but if\n\
3077 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3078 nevertheless truncate the shift count, you may get better code\n\
3080 unsigned HOST_WIDE_INT, (machine_mode mode),
3081 default_shift_truncation_mask)
3083 /* Return the number of divisions in the given MODE that should be present,
3084 so that it is profitable to turn the division into a multiplication by
3087 (min_divisions_for_recip_mul,
3088 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3089 divisions by the same divisor, by turning them into multiplications by\n\
3090 the reciprocal. This target hook specifies the minimum number of divisions\n\
3091 that should be there for GCC to perform the optimization for a variable\n\
3092 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3093 has an instruction for the division, and 2 if it does not.",
3094 unsigned int, (machine_mode mode),
3095 default_min_divisions_for_recip_mul)
3097 /* If the representation of integral MODE is such that values are
3098 always sign-extended to a wider mode MODE_REP then return
3099 SIGN_EXTEND. Return UNKNOWN otherwise. */
3100 /* Note that the return type ought to be RTX_CODE, but that's not
3101 necessarily defined at this point. */
3104 "The representation of an integral mode can be such that the values\n\
3105 are always extended to a wider integral mode. Return\n\
3106 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3107 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3108 otherwise. (Currently, none of the targets use zero-extended\n\
3109 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3110 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3111 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3112 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3113 widest integral mode and currently we take advantage of this fact.)\n\
3115 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3116 value even if the extension is not performed on certain hard registers\n\
3117 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3118 @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.\n\
3120 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3121 describe two related properties. If you define\n\
3122 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3123 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3126 In order to enforce the representation of @code{mode},\n\
3127 @code{TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3129 int, (machine_mode mode, machine_mode rep_mode),
3130 default_mode_rep_extended)
3132 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3134 (valid_pointer_mode,
3135 "Define this to return nonzero if the port can handle pointers\n\
3136 with machine mode @var{mode}. The default version of this\n\
3137 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3138 bool, (machine_mode mode),
3139 default_valid_pointer_mode)
3141 /* Disambiguate with errno. */
3143 (ref_may_alias_errno,
3144 "Define this to return nonzero if the memory reference @var{ref}\
3145 may alias with the system C library errno location. The default\
3146 version of this hook assumes the system C library errno location\
3147 is either a declaration of type int or accessed by dereferencing\
3149 bool, (struct ao_ref *ref),
3150 default_ref_may_alias_errno)
3152 /* Support for named address spaces. */
3154 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3155 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3157 /* MODE to use for a pointer into another address space. */
3160 "Define this to return the machine mode to use for pointers to\n\
3161 @var{address_space} if the target supports named address spaces.\n\
3162 The default version of this hook returns @code{ptr_mode}.",
3163 machine_mode, (addr_space_t address_space),
3164 default_addr_space_pointer_mode)
3166 /* MODE to use for an address in another address space. */
3169 "Define this to return the machine mode to use for addresses in\n\
3170 @var{address_space} if the target supports named address spaces.\n\
3171 The default version of this hook returns @code{Pmode}.",
3172 machine_mode, (addr_space_t address_space),
3173 default_addr_space_address_mode)
3175 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3176 in another address space. */
3178 (valid_pointer_mode,
3179 "Define this to return nonzero if the port can handle pointers\n\
3180 with machine mode @var{mode} to address space @var{as}. This target\n\
3181 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3182 except that it includes explicit named address space support. The default\n\
3183 version of this hook returns true for the modes returned by either the\n\
3184 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3185 target hooks for the given address space.",
3186 bool, (machine_mode mode, addr_space_t as),
3187 default_addr_space_valid_pointer_mode)
3189 /* True if an address is a valid memory address to a given named address
3190 space for a given mode. */
3192 (legitimate_address_p,
3193 "Define this to return true if @var{exp} is a valid address for mode\n\
3194 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3195 parameter says whether strict addressing is in effect after reload has\n\
3196 finished. This target hook is the same as the\n\
3197 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3198 explicit named address space support.",
3199 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3200 default_addr_space_legitimate_address_p)
3202 /* Return an updated address to convert an invalid pointer to a named
3203 address space to a valid one. If NULL_RTX is returned use machine
3204 independent methods to make the address valid. */
3206 (legitimize_address,
3207 "Define this to modify an invalid address @var{x} to be a valid address\n\
3208 with mode @var{mode} in the named address space @var{as}. This target\n\
3209 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3210 except that it includes explicit named address space support.",
3211 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3212 default_addr_space_legitimize_address)
3214 /* True if one named address space is a subset of another named address. */
3217 "Define this to return whether the @var{subset} named address space is\n\
3218 contained within the @var{superset} named address space. Pointers to\n\
3219 a named address space that is a subset of another named address space\n\
3220 will be converted automatically without a cast if used together in\n\
3221 arithmetic operations. Pointers to a superset address space can be\n\
3222 converted to pointers to a subset address space via explicit casts.",
3223 bool, (addr_space_t subset, addr_space_t superset),
3224 default_addr_space_subset_p)
3226 /* Function to convert an rtl expression from one address space to another. */
3229 "Define this to convert the pointer expression represented by the RTL\n\
3230 @var{op} with type @var{from_type} that points to a named address\n\
3231 space to a new pointer expression with type @var{to_type} that points\n\
3232 to a different named address space. When this hook it called, it is\n\
3233 guaranteed that one of the two address spaces is a subset of the other,\n\
3234 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3235 rtx, (rtx op, tree from_type, tree to_type),
3236 default_addr_space_convert)
3238 HOOK_VECTOR_END (addr_space)
3241 #define HOOK_PREFIX "TARGET_"
3243 /* True if MODE is valid for the target. By "valid", we mean able to
3244 be manipulated in non-trivial ways. In particular, this means all
3245 the arithmetic is supported. */
3247 (scalar_mode_supported_p,
3248 "Define this to return nonzero if the port is prepared to handle\n\
3249 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3250 considered supported, all the basic arithmetic and comparisons\n\
3253 The default version of this hook returns true for any mode\n\
3254 required to handle the basic C types (as defined by the port).\n\
3255 Included here are the double-word arithmetic supported by the\n\
3256 code in @file{optabs.c}.",
3257 bool, (machine_mode mode),
3258 default_scalar_mode_supported_p)
3260 /* Similarly for vector modes. "Supported" here is less strict. At
3261 least some operations are supported; need to check optabs or builtins
3262 for further details. */
3264 (vector_mode_supported_p,
3265 "Define this to return nonzero if the port is prepared to handle\n\
3266 insns involving vector mode @var{mode}. At the very least, it\n\
3267 must have move patterns for this mode.",
3268 bool, (machine_mode mode),
3269 hook_bool_mode_false)
3273 "This hook can be used to define the alignment for a vector of type\n\
3274 @var{type}, in order to comply with a platform ABI. The default is to\n\
3275 require natural alignment for vector types. The alignment returned by\n\
3276 this hook must be a power-of-two multiple of the default alignment of\n\
3277 the vector element type.",
3278 HOST_WIDE_INT, (const_tree type),
3279 default_vector_alignment)
3281 /* True if we should try to use a scalar mode to represent an array,
3282 overriding the usual MAX_FIXED_MODE limit. */
3284 (array_mode_supported_p,
3285 "Return true if GCC should try to use a scalar mode to store an array\n\
3286 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3287 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3288 and allows GCC to use any defined integer mode.\n\
3290 One use of this hook is to support vector load and store operations\n\
3291 that operate on several homogeneous vectors. For example, ARM NEON\n\
3292 has operations like:\n\
3295 int8x8x3_t vld3_s8 (const int8_t *)\n\
3296 @end smallexample\n\
3298 where the return type is defined as:\n\
3301 typedef struct int8x8x3_t\n\
3305 @end smallexample\n\
3307 If this hook allows @code{val} to have a scalar mode, then\n\
3308 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3309 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3310 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3311 hook_bool_mode_uhwi_false)
3314 (libgcc_floating_mode_supported_p,
3315 "Define this to return nonzero if libgcc provides support for the \n\
3316 floating-point mode @var{mode}, which is known to pass \n\
3317 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3318 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3319 @code{XFmode} and @code{TFmode}, if such modes exist.",
3320 bool, (machine_mode mode),
3321 default_libgcc_floating_mode_supported_p)
3323 /* Compute cost of moving data from a register of class FROM to one of
3326 (register_move_cost,
3327 "This target hook should return the cost of moving data of mode @var{mode}\n\
3328 from a register in class @var{from} to one in class @var{to}. The classes\n\
3329 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3330 A value of 2 is the default; other values are interpreted relative to\n\
3333 It is not required that the cost always equal 2 when @var{from} is the\n\
3334 same as @var{to}; on some machines it is expensive to move between\n\
3335 registers if they are not general registers.\n\
3337 If reload sees an insn consisting of a single @code{set} between two\n\
3338 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3339 classes returns a value of 2, reload does not check to ensure that the\n\
3340 constraints of the insn are met. Setting a cost of other than 2 will\n\
3341 allow reload to verify that the constraints are met. You should do this\n\
3342 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3344 The default version of this function returns 2.",
3345 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3346 default_register_move_cost)
3348 /* Compute cost of moving registers to/from memory. */
3349 /* ??? Documenting the argument types for this hook requires a GFDL
3350 license grant. Also, the documentation uses a different name for RCLASS. */
3353 "This target hook should return the cost of moving data of mode @var{mode}\n\
3354 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3355 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3356 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3357 If moving between registers and memory is more expensive than between two\n\
3358 registers, you should add this target hook to express the relative cost.\n\
3360 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3361 the cost of copying via a secondary reload register, if one is\n\
3362 needed. If your machine requires a secondary reload register to copy\n\
3363 between memory and a register of @var{rclass} but the reload mechanism is\n\
3364 more complex than copying via an intermediate, use this target hook to\n\
3365 reflect the actual cost of the move.\n\
3367 GCC defines the function @code{memory_move_secondary_cost} if\n\
3368 secondary reloads are needed. It computes the costs due to copying via\n\
3369 a secondary register. If your machine copies from memory using a\n\
3370 secondary register in the conventional way but the default base value of\n\
3371 4 is not correct for your machine, use this target hook to add some other\n\
3372 value to the result of that function. The arguments to that function\n\
3373 are the same as to this target hook.",
3374 int, (machine_mode mode, reg_class_t rclass, bool in),
3375 default_memory_move_cost)
3378 (use_by_pieces_infrastructure_p,
3379 "GCC will attempt several strategies when asked to copy between\n\
3380 two areas of memory, or to set, clear or store to memory, for example\n\
3381 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3382 implements such memory operations as a sequence of load, store or move\n\
3383 insns. Alternate strategies are to expand the\n\
3384 @code{movmem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3385 unit-by-unit, loop-based operations.\n\
3387 This target hook should return true if, for a memory operation with a\n\
3388 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3389 infrastructure is expected to result in better code generation.\n\
3390 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3393 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3394 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES}.\n\
3395 These describe the type of memory operation under consideration.\n\
3397 The parameter @var{speed_p} is true if the code is currently being\n\
3398 optimized for speed rather than size.\n\
3400 Returning true for higher values of @var{size} can improve code generation\n\
3401 for speed if the target does not provide an implementation of the\n\
3402 @code{movmem} or @code{setmem} standard names, if the @code{movmem} or\n\
3403 @code{setmem} implementation would be more expensive than a sequence of\n\
3404 insns, or if the overhead of a library call would dominate that of\n\
3405 the body of the memory operation.\n\
3407 Returning true for higher values of @code{size} may also cause an increase\n\
3408 in code size, for example where the number of insns emitted to perform a\n\
3409 move would be greater than that of a library call.",
3410 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3411 enum by_pieces_operation op, bool speed_p),
3412 default_use_by_pieces_infrastructure_p)
3414 /* True for MODE if the target expects that registers in this mode will
3415 be allocated to registers in a small register class. The compiler is
3416 allowed to use registers explicitly used in the rtl as spill registers
3417 but it should prevent extending the lifetime of these registers. */
3419 (small_register_classes_for_mode_p,
3420 "Define this to return nonzero for machine modes for which the port has\n\
3421 small register classes. If this target hook returns nonzero for a given\n\
3422 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3423 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3424 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3427 On some machines, it is risky to let hard registers live across arbitrary\n\
3428 insns. Typically, these machines have instructions that require values\n\
3429 to be in specific registers (like an accumulator), and reload will fail\n\
3430 if the required hard register is used for another purpose across such an\n\
3433 Passes before reload do not know which hard registers will be used\n\
3434 in an instruction, but the machine modes of the registers set or used in\n\
3435 the instruction are already known. And for some machines, register\n\
3436 classes are small for, say, integer registers but not for floating point\n\
3437 registers. For example, the AMD x86-64 architecture requires specific\n\
3438 registers for the legacy x86 integer instructions, but there are many\n\
3439 SSE registers for floating point operations. On such targets, a good\n\
3440 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3441 machine modes but zero for the SSE register classes.\n\
3443 The default version of this hook returns false for any mode. It is always\n\
3444 safe to redefine this hook to return with a nonzero value. But if you\n\
3445 unnecessarily define it, you will reduce the amount of optimizations\n\
3446 that can be performed in some cases. If you do not define this hook\n\
3447 to return a nonzero value when it is required, the compiler will run out\n\
3448 of spill registers and print a fatal error message.",
3449 bool, (machine_mode mode),
3450 hook_bool_mode_false)
3452 /* Register number for a flags register. Only needs to be defined if the
3453 target is constrainted to use post-reload comparison elimination. */
3456 "If the target has a dedicated flags register, and it needs to use the\
3457 post-reload comparison elimination pass, then this value should be set\
3459 unsigned int, INVALID_REGNUM)
3461 /* Compute a (partial) cost for rtx X. Return true if the complete
3462 cost has been computed, and false if subexpressions should be
3463 scanned. In either case, *TOTAL contains the cost result. */
3464 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3465 not necessarily defined at this point. */
3468 "This target hook describes the relative costs of RTL expressions.\n\
3470 The cost may depend on the precise form of the expression, which is\n\
3471 available for examination in @var{x}, and the fact that @var{x} appears\n\
3472 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3473 That is, the hook can assume that there is some rtx @var{y} such\n\
3474 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3475 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3476 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3478 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3479 do not have a mode, the mode in which @var{x} is used.\n\
3481 In implementing this hook, you can use the construct\n\
3482 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3485 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3486 for the cost of the expression. The hook should modify this value as\n\
3487 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3488 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3489 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3491 When optimizing for code size, i.e.@: when @code{speed} is\n\
3492 false, this target hook should be used to estimate the relative\n\
3493 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3495 The hook returns true when all subexpressions of @var{x} have been\n\
3496 processed, and false when @code{rtx_cost} should recurse.",
3497 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3498 hook_bool_rtx_mode_int_int_intp_bool_false)
3500 /* Compute the cost of X, used as an address. Never called with
3501 invalid addresses. */
3504 "This hook computes the cost of an addressing mode that contains\n\
3505 @var{address}. If not defined, the cost is computed from\n\
3506 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3508 For most CISC machines, the default cost is a good approximation of the\n\
3509 true cost of the addressing mode. However, on RISC machines, all\n\
3510 instructions normally have the same length and execution time. Hence\n\
3511 all addresses will have equal costs.\n\
3513 In cases where more than one form of an address is known, the form with\n\
3514 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3515 cost, the one that is the most complex will be used.\n\
3517 For example, suppose an address that is equal to the sum of a register\n\
3518 and a constant is used twice in the same basic block. When this macro\n\
3519 is not defined, the address will be computed in a register and memory\n\
3520 references will be indirect through that register. On machines where\n\
3521 the cost of the addressing mode containing the sum is no higher than\n\
3522 that of a simple indirect reference, this will produce an additional\n\
3523 instruction and possibly require an additional register. Proper\n\
3524 specification of this macro eliminates this overhead for such machines.\n\
3526 This hook is never called with an invalid address.\n\
3528 On machines where an address involving more than one register is as\n\
3529 cheap as an address computation involving only one register, defining\n\
3530 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3531 be live over a region of code where only one would have been if\n\
3532 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3533 should be considered in the definition of this macro. Equivalent costs\n\
3534 should probably only be given to addresses with different numbers of\n\
3535 registers on machines with lots of registers.",
3536 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3537 default_address_cost)
3539 /* Permit speculative instructions in delay slots during delayed-branch
3542 (no_speculation_in_delay_slots_p,
3543 "This predicate controls the use of the eager delay slot filler to disallow\n\
3544 speculatively executed instructions being placed in delay slots. Targets\n\
3545 such as certain MIPS architectures possess both branches with and without\n\
3546 delay slots. As the eager delay slot filler can decrease performance,\n\
3547 disabling it is beneficial when ordinary branches are available. Use of\n\
3548 delay slot branches filled using the basic filler is often still desirable\n\
3549 as the delay slot can hide a pipeline bubble.", bool, (void),
3550 hook_bool_void_false)
3552 /* Return where to allocate pseudo for a given hard register initial value. */
3554 (allocate_initial_value,
3556 When the initial value of a hard register has been copied in a pseudo\n\
3557 register, it is often not necessary to actually allocate another register\n\
3558 to this pseudo register, because the original hard register or a stack slot\n\
3559 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3560 is called at the start of register allocation once for each hard register\n\
3561 that had its initial value copied by using\n\
3562 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3563 Possible values are @code{NULL_RTX}, if you don't want\n\
3564 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3565 the hard register itself, if it is known not to be clobbered---or a\n\
3567 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3568 it might decide to use another register anyways.\n\
3569 You may use @code{current_function_is_leaf} or \n\
3570 @code{REG_N_SETS} in the hook to determine if the hard\n\
3571 register in question will not be clobbered.\n\
3572 The default value of this hook is @code{NULL}, which disables any special\n\
3574 rtx, (rtx hard_reg), NULL)
3576 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3577 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3580 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3581 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3582 this hook to enhance precision of analysis for @code{unspec} and\n\
3583 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3584 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3586 int, (const_rtx x, unsigned flags),
3587 default_unspec_may_trap_p)
3589 /* Given a register, this hook should return a parallel of registers
3590 to represent where to find the register pieces. Define this hook
3591 if the register and its mode are represented in Dwarf in
3592 non-contiguous locations, or if the register should be
3593 represented in more than one register in Dwarf. Otherwise, this
3594 hook should return NULL_RTX. */
3596 (dwarf_register_span,
3597 "Given a register, this hook should return a parallel of registers to\n\
3598 represent where to find the register pieces. Define this hook if the\n\
3599 register and its mode are represented in Dwarf in non-contiguous\n\
3600 locations, or if the register should be represented in more than one\n\
3601 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3602 If not defined, the default is to return @code{NULL_RTX}.",
3606 /* Given a register return the mode of the corresponding DWARF frame
3609 (dwarf_frame_reg_mode,
3610 "Given a register, this hook should return the mode which the\n\
3611 corresponding Dwarf frame register should have. This is normally\n\
3612 used to return a smaller mode than the raw mode to prevent call\n\
3613 clobbered parts of a register altering the frame register size",
3614 machine_mode, (int regno),
3615 default_dwarf_frame_reg_mode)
3617 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3618 entries not corresponding directly to registers below
3619 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3620 code, given the address of the table. */
3622 (init_dwarf_reg_sizes_extra,
3623 "If some registers are represented in Dwarf-2 unwind information in\n\
3624 multiple pieces, define this hook to fill in information about the\n\
3625 sizes of those pieces in the table used by the unwinder at runtime.\n\
3626 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3627 filling in a single size corresponding to each hard register;\n\
3628 @var{address} is the address of the table.",
3629 void, (tree address),
3632 /* Fetch the fixed register(s) which hold condition codes, for
3633 targets where it makes sense to look for duplicate assignments to
3634 the condition codes. This should return true if there is such a
3635 register, false otherwise. The arguments should be set to the
3636 fixed register numbers. Up to two condition code registers are
3637 supported. If there is only one for this target, the int pointed
3638 at by the second argument should be set to -1. */
3640 (fixed_condition_code_regs,
3641 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3642 register rather than a pseudo-register to hold condition codes, the\n\
3643 regular CSE passes are often not able to identify cases in which the\n\
3644 hard register is set to a common value. Use this hook to enable a\n\
3645 small pass which optimizes such cases. This hook should return true\n\
3646 to enable this pass, and it should set the integers to which its\n\
3647 arguments point to the hard register numbers used for condition codes.\n\
3648 When there is only one such register, as is true on most systems, the\n\
3649 integer pointed to by @var{p2} should be set to\n\
3650 @code{INVALID_REGNUM}.\n\
3652 The default version of this hook returns false.",
3653 bool, (unsigned int *p1, unsigned int *p2),
3654 hook_bool_uintp_uintp_false)
3656 /* If two condition code modes are compatible, return a condition
3657 code mode which is compatible with both, such that a comparison
3658 done in the returned mode will work for both of the original
3659 modes. If the condition code modes are not compatible, return
3662 (cc_modes_compatible,
3663 "On targets which use multiple condition code modes in class\n\
3664 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3665 validly done in more than one mode. On such a system, define this\n\
3666 target hook to take two mode arguments and to return a mode in which\n\
3667 both comparisons may be validly done. If there is no such mode,\n\
3668 return @code{VOIDmode}.\n\
3670 The default version of this hook checks whether the modes are the\n\
3671 same. If they are, it returns that mode. If they are different, it\n\
3672 returns @code{VOIDmode}.",
3673 machine_mode, (machine_mode m1, machine_mode m2),
3674 default_cc_modes_compatible)
3676 /* Do machine-dependent code transformations. Called just before
3677 delayed-branch scheduling. */
3679 (machine_dependent_reorg,
3680 "If non-null, this hook performs a target-specific pass over the\n\
3681 instruction stream. The compiler will run it at all optimization levels,\n\
3682 just before the point at which it normally does delayed-branch scheduling.\n\
3684 The exact purpose of the hook varies from target to target. Some use\n\
3685 it to do transformations that are necessary for correctness, such as\n\
3686 laying out in-function constant pools or avoiding hardware hazards.\n\
3687 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3689 You need not implement the hook if it has nothing to do. The default\n\
3690 definition is null.",
3693 /* Create the __builtin_va_list type. */
3695 (build_builtin_va_list,
3696 "This hook returns a type node for @code{va_list} for the target.\n\
3697 The default version of the hook returns @code{void*}.",
3699 std_build_builtin_va_list)
3701 /* Enumerate the va list variants. */
3704 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3705 to iterate through the target specific builtin types for va_list. The\n\
3706 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3707 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3709 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3710 this macro and are set to the name of the va_list builtin type and its\n\
3712 If the return value of this macro is zero, then there is no more element.\n\
3713 Otherwise the @var{IDX} should be increased for the next call of this\n\
3714 macro to iterate through all types.",
3715 int, (int idx, const char **pname, tree *ptree),
3718 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3721 "This hook returns the va_list type of the calling convention specified by\n\
3723 The default version of this hook returns @code{va_list_type_node}.",
3724 tree, (tree fndecl),
3727 /* Get the __builtin_va_list type dependent on input type. */
3729 (canonical_va_list_type,
3730 "This hook returns the va_list type of the calling convention specified by the\n\
3731 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3734 std_canonical_va_list_type)
3736 /* ??? Documenting this hook requires a GFDL license grant. */
3738 (expand_builtin_va_start,
3739 "Expand the @code{__builtin_va_start} builtin.",
3740 void, (tree valist, rtx nextarg), NULL)
3742 /* Gimplifies a VA_ARG_EXPR. */
3744 (gimplify_va_arg_expr,
3745 "This hook performs target-specific gimplification of\n\
3746 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3747 arguments to @code{va_arg}; the latter two are as in\n\
3748 @code{gimplify.c:gimplify_expr}.",
3749 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3750 std_gimplify_va_arg_expr)
3752 /* Validity-checking routines for PCH files, target-specific.
3753 get_pch_validity returns a pointer to the data to be stored,
3754 and stores the size in its argument. pch_valid_p gets the same
3755 information back and returns NULL if the PCH is valid,
3756 or an error message if not. */
3759 "This hook returns a pointer to the data needed by\n\
3760 @code{TARGET_PCH_VALID_P} and sets\n\
3761 @samp{*@var{sz}} to the size of the data in bytes.",
3762 void *, (size_t *sz),
3763 default_get_pch_validity)
3767 "This hook checks whether the options used to create a PCH file are\n\
3768 compatible with the current settings. It returns @code{NULL}\n\
3769 if so and a suitable error message if not. Error messages will\n\
3770 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3772 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3773 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3774 It's safe to assume that the data was created by the same version of the\n\
3775 compiler, so no format checking is needed.\n\
3777 The default definition of @code{default_pch_valid_p} should be\n\
3778 suitable for most targets.",
3779 const char *, (const void *data, size_t sz),
3780 default_pch_valid_p)
3784 "Called before writing out a PCH file. If the target has some\n\
3785 garbage-collected data that needs to be in a particular state on PCH loads,\n\
3786 it can use this hook to enforce that state. Very few targets need\n\
3787 to do anything here.",
3791 /* If nonnull, this function checks whether a PCH file with the
3792 given set of target flags can be used. It returns NULL if so,
3793 otherwise it returns an error message. */
3795 (check_pch_target_flags,
3796 "If this hook is nonnull, the default implementation of\n\
3797 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
3798 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
3799 @code{target_flags} had when the PCH file was created. The return\n\
3800 value is the same as for @code{TARGET_PCH_VALID_P}.",
3801 const char *, (int pch_flags), NULL)
3803 /* True if the compiler should give an enum type only as many
3804 bytes as it takes to represent the range of possible values of
3807 (default_short_enums,
3808 "This target hook should return true if the compiler should give an\n\
3809 @code{enum} type only as many bytes as it takes to represent the range\n\
3810 of possible values of that type. It should return false if all\n\
3811 @code{enum} types should be allocated like @code{int}.\n\
3813 The default is to return false.",
3815 hook_bool_void_false)
3817 /* This target hook returns an rtx that is used to store the address
3818 of the current frame into the built-in setjmp buffer. */
3820 (builtin_setjmp_frame_value,
3821 "This target hook should return an rtx that is used to store\n\
3822 the address of the current frame into the built in @code{setjmp} buffer.\n\
3823 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
3824 machines. One reason you may need to define this target hook is if\n\
3825 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
3827 default_builtin_setjmp_frame_value)
3829 /* This target hook should manipulate the outputs, inputs, constraints,
3830 and clobbers the port wishes for pre-processing the asm. */
3833 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
3834 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
3835 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
3836 to avoid clobbering a register that is already used by the asm.\n\
3838 It may modify the @var{outputs}, @var{inputs}, and @var{constraints}\n\
3839 as necessary for other pre-processing. In this case the return value is\n\
3840 a sequence of insns to emit after the asm.",
3842 (vec<rtx>& outputs, vec<rtx>& inputs, vec<const char *>& constraints,
3843 vec<rtx>& clobbers, HARD_REG_SET& clobbered_regs),
3846 /* This target hook allows the backend to specify a calling convention
3847 in the debug information. This function actually returns an
3848 enum dwarf_calling_convention, but because of forward declarations
3849 and not wanting to include dwarf2.h everywhere target.h is included
3850 the function is being declared as an int. */
3852 (dwarf_calling_convention,
3853 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
3854 be emitted for each function. Instead of an integer return the enum\n\
3855 value for the @code{DW_CC_} tag.",
3856 int, (const_tree function),
3857 hook_int_const_tree_0)
3859 /* This target hook allows the backend to emit frame-related insns that
3860 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
3861 engine will invoke it on insns of the form
3862 (set (reg) (unspec [...] UNSPEC_INDEX))
3864 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
3865 to let the backend emit the call frame instructions. */
3867 (dwarf_handle_frame_unspec,
3868 "This target hook allows the backend to emit frame-related insns that\n\
3869 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
3870 info engine will invoke it on insns of the form\n\
3872 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
3873 @end smallexample\n\
3876 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
3877 @end smallexample\n\
3878 to let the backend emit the call frame instructions. @var{label} is\n\
3879 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
3880 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
3881 void, (const char *label, rtx pattern, int index), NULL)
3883 /* ??? Documenting this hook requires a GFDL license grant. */
3885 (stdarg_optimize_hook,
3886 "Perform architecture specific checking of statements gimplified\
3887 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
3888 the statement doesn't need to be checked for @code{va_list} references.",
3889 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
3891 /* This target hook allows the operating system to override the DECL
3892 that represents the external variable that contains the stack
3893 protection guard variable. The type of this DECL is ptr_type_node. */
3895 (stack_protect_guard,
3896 "This hook returns a @code{DECL} node for the external variable to use\n\
3897 for the stack protection guard. This variable is initialized by the\n\
3898 runtime to some random value and is used to initialize the guard value\n\
3899 that is placed at the top of the local stack frame. The type of this\n\
3900 variable must be @code{ptr_type_node}.\n\
3902 The default version of this hook creates a variable called\n\
3903 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
3905 default_stack_protect_guard)
3907 /* This target hook allows the operating system to override the CALL_EXPR
3908 that is invoked when a check vs the guard variable fails. */
3910 (stack_protect_fail,
3911 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
3912 stack protect guard variable has been modified. This expression should\n\
3913 involve a call to a @code{noreturn} function.\n\
3915 The default version of this hook invokes a function called\n\
3916 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
3917 normally defined in @file{libgcc2.c}.",
3919 default_external_stack_protect_fail)
3923 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
3924 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
3925 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
3926 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
3927 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
3928 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
3929 loop is only entered from the top.\n\
3931 This hook is only used if @code{doloop_end} is available. The default\n\
3932 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
3933 if the loop must be the innermost, and if there are no other restrictions.",
3934 bool, (const widest_int &iterations, const widest_int &iterations_max,
3935 unsigned int loop_depth, bool entered_at_top),
3936 hook_bool_wint_wint_uint_bool_true)
3938 /* Returns NULL if target supports the insn within a doloop block,
3939 otherwise it returns an error message. */
3941 (invalid_within_doloop,
3943 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
3944 low-overhead loop, otherwise return a string explaining why doloop\n\
3945 could not be applied.\n\
3947 Many targets use special registers for low-overhead looping. For any\n\
3948 instruction that clobbers these this function should return a string indicating\n\
3949 the reason why the doloop could not be applied.\n\
3950 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
3951 loops containing function calls or branch on table instructions.",
3952 const char *, (const rtx_insn *insn),
3953 default_invalid_within_doloop)
3955 /* Returns true for a legitimate combined insn. */
3957 (legitimate_combined_insn,
3958 "Take an instruction in @var{insn} and return @code{false} if the instruction\
3959 is not appropriate as a combination of two or more instructions. The\
3960 default is to accept all instructions.",
3961 bool, (rtx_insn *insn),
3962 hook_bool_rtx_insn_true)
3965 (valid_dllimport_attribute_p,
3966 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
3967 specified. Use this hook if the target needs to add extra validation\
3968 checks to @code{handle_dll_attribute}.",
3969 bool, (const_tree decl),
3970 hook_bool_const_tree_true)
3972 /* If non-zero, align constant anchors in CSE to a multiple of this
3976 "On some architectures it can take multiple instructions to synthesize\n\
3977 a constant. If there is another constant already in a register that\n\
3978 is close enough in value then it is preferable that the new constant\n\
3979 is computed from this register using immediate addition or\n\
3980 subtraction. We accomplish this through CSE. Besides the value of\n\
3981 the constant we also add a lower and an upper constant anchor to the\n\
3982 available expressions. These are then queried when encountering new\n\
3983 constants. The anchors are computed by rounding the constant up and\n\
3984 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
3985 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
3986 accepted by immediate-add plus one. We currently assume that the\n\
3987 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
3988 MIPS, where add-immediate takes a 16-bit signed value,\n\
3989 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
3990 is zero, which disables this optimization.",
3991 unsigned HOST_WIDE_INT, 0)
3993 /* Defines, which target-dependent bits (upper 16) are used by port */
3996 "Validate target specific memory model mask bits. When NULL no target specific\n\
3997 memory model bits are allowed.",
3998 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4000 /* Defines an offset bitwise ored into shifted address to get corresponding
4001 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4002 supported by the target. */
4004 (asan_shadow_offset,
4005 "Return the offset bitwise ored into shifted address to get corresponding\n\
4006 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4007 supported by the target.",
4008 unsigned HOST_WIDE_INT, (void),
4011 /* Functions relating to calls - argument passing, returns, etc. */
4012 /* Members of struct call have no special macro prefix. */
4013 HOOK_VECTOR (TARGET_CALLS, calls)
4016 (promote_function_mode,
4017 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4018 function return values. The target hook should return the new mode\n\
4019 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4020 change signedness. This function is called only for scalar @emph{or\n\
4023 @var{for_return} allows to distinguish the promotion of arguments and\n\
4024 return values. If it is @code{1}, a return value is being promoted and\n\
4025 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4026 If it is @code{2}, the returned mode should be that of the register in\n\
4027 which an incoming parameter is copied, or the outgoing result is computed;\n\
4028 then the hook should return the same mode as @code{promote_mode}, though\n\
4029 the signedness may be different.\n\
4031 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4033 The default is to not promote arguments and return values. You can\n\
4034 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4035 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4036 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4037 const_tree funtype, int for_return),
4038 default_promote_function_mode)
4041 (promote_prototypes,
4042 "This target hook returns @code{true} if an argument declared in a\n\
4043 prototype as an integral type smaller than @code{int} should actually be\n\
4044 passed as an @code{int}. In addition to avoiding errors in certain\n\
4045 cases of mismatch, it also makes for better code on certain machines.\n\
4046 The default is to not promote prototypes.",
4047 bool, (const_tree fntype),
4048 hook_bool_const_tree_false)
4052 "This target hook should return the location of the structure value\n\
4053 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4054 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4055 be @code{NULL}, for libcalls. You do not need to define this target\n\
4056 hook if the address is always passed as an ``invisible'' first\n\
4059 On some architectures the place where the structure value address\n\
4060 is found by the called function is not the same place that the\n\
4061 caller put it. This can be due to register windows, or it could\n\
4062 be because the function prologue moves it to a different place.\n\
4063 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4064 the context of the called function, and @code{0} in the context of\n\
4067 If @var{incoming} is nonzero and the address is to be found on the\n\
4068 stack, return a @code{mem} which refers to the frame pointer. If\n\
4069 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4070 structure value address at the beginning of a function. If you need\n\
4071 to emit adjusting code, you should do it at this point.",
4072 rtx, (tree fndecl, int incoming),
4073 hook_rtx_tree_int_null)
4076 (omit_struct_return_reg,
4077 "Normally, when a function returns a structure by memory, the address\n\
4078 is passed as an invisible pointer argument, but the compiler also\n\
4079 arranges to return the address from the function like it would a normal\n\
4080 pointer return value. Define this to true if that behaviour is\n\
4081 undesirable on your target.",
4086 "This target hook should return a nonzero value to say to return the\n\
4087 function value in memory, just as large structures are always returned.\n\
4088 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4089 will be the type of the function doing the returning, or @code{NULL} for\n\
4092 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4093 by this function. Also, the option @option{-fpcc-struct-return}\n\
4094 takes effect regardless of this macro. On most systems, it is\n\
4095 possible to leave the hook undefined; this causes a default\n\
4096 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4097 values, and 0 otherwise.\n\
4099 Do not use this hook to indicate that structures and unions should always\n\
4100 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4102 bool, (const_tree type, const_tree fntype),
4103 default_return_in_memory)
4107 "This hook should return true if values of type @var{type} are returned\n\
4108 at the most significant end of a register (in other words, if they are\n\
4109 padded at the least significant end). You can assume that @var{type}\n\
4110 is returned in a register; the caller is required to check this.\n\
4112 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4113 be able to hold the complete return value. For example, if a 1-, 2-\n\
4114 or 3-byte structure is returned at the most significant end of a\n\
4115 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4116 @code{SImode} rtx.",
4117 bool, (const_tree type),
4118 hook_bool_const_tree_false)
4120 /* Return true if a parameter must be passed by reference. TYPE may
4121 be null if this is a libcall. CA may be null if this query is
4122 from __builtin_va_arg. */
4125 "This target hook should return @code{true} if an argument at the\n\
4126 position indicated by @var{cum} should be passed by reference. This\n\
4127 predicate is queried after target independent reasons for being\n\
4128 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
4130 If the hook returns true, a copy of that argument is made in memory and a\n\
4131 pointer to the argument is passed instead of the argument itself.\n\
4132 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4135 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4136 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4139 (expand_builtin_saveregs,
4140 "If defined, this hook produces the machine-specific code for a call to\n\
4141 @code{__builtin_saveregs}. This code will be moved to the very\n\
4142 beginning of the function, before any parameter access are made. The\n\
4143 return value of this function should be an RTX that contains the value\n\
4144 to use as the return of @code{__builtin_saveregs}.",
4146 default_expand_builtin_saveregs)
4148 /* Returns pretend_argument_size. */
4150 (setup_incoming_varargs,
4151 "This target hook offers an alternative to using\n\
4152 @code{__builtin_saveregs} and defining the hook\n\
4153 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4154 register arguments into the stack so that all the arguments appear to\n\
4155 have been passed consecutively on the stack. Once this is done, you can\n\
4156 use the standard implementation of varargs that works for machines that\n\
4157 pass all their arguments on the stack.\n\
4159 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4160 structure, containing the values that are obtained after processing the\n\
4161 named arguments. The arguments @var{mode} and @var{type} describe the\n\
4162 last named argument---its machine mode and its data type as a tree node.\n\
4164 The target hook should do two things: first, push onto the stack all the\n\
4165 argument registers @emph{not} used for the named arguments, and second,\n\
4166 store the size of the data thus pushed into the @code{int}-valued\n\
4167 variable pointed to by @var{pretend_args_size}. The value that you\n\
4168 store here will serve as additional offset for setting up the stack\n\
4171 Because you must generate code to push the anonymous arguments at\n\
4172 compile time without knowing their data types,\n\
4173 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4174 have just a single category of argument register and use it uniformly\n\
4175 for all data types.\n\
4177 If the argument @var{second_time} is nonzero, it means that the\n\
4178 arguments of the function are being analyzed for the second time. This\n\
4179 happens for an inline function, which is not actually compiled until the\n\
4180 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4181 not generate any instructions in this case.",
4182 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4183 int *pretend_args_size, int second_time),
4184 default_setup_incoming_varargs)
4187 (load_bounds_for_arg,
4188 "This hook is used by expand pass to emit insn to load bounds of\n\
4189 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4190 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4191 memory, then bounds are loaded as for regular pointer loaded from\n\
4192 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4193 constant holding number of the target dependent special slot which\n\
4194 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4195 rtx, (rtx slot, rtx arg, rtx slot_no),
4196 default_load_bounds_for_arg)
4199 (store_bounds_for_arg,
4200 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4201 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4202 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4203 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4204 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4205 constant holding number of the target dependent special slot which\n\
4206 should be used to store @var{bounds}.",
4207 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4208 default_store_bounds_for_arg)
4211 (load_returned_bounds,
4212 "This hook is used by expand pass to emit insn to load bounds\n\
4213 returned by function call in @var{slot}. Hook returns RTX holding\n\
4216 default_load_returned_bounds)
4219 (store_returned_bounds,
4220 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4221 returned by function call into @var{slot}.",
4222 void, (rtx slot, rtx bounds),
4223 default_store_returned_bounds)
4226 (setup_incoming_vararg_bounds,
4227 "Use it to store bounds for anonymous register arguments stored\n\
4228 into the stack. Arguments meaning is similar to\n\
4229 @code{TARGET_SETUP_INCOMING_VARARGS}.",
4230 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
4231 int *pretend_args_size, int second_time),
4232 default_setup_incoming_vararg_bounds)
4236 "While generating RTL for a function call, this target hook is invoked once\n\
4237 for each argument passed to the function, either a register returned by\n\
4238 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4239 before the point where argument registers are stored. The type of the\n\
4240 function to be called is also passed as the second argument; it is\n\
4241 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4242 invoked just after the code to copy the return reg has been emitted.\n\
4243 This functionality can be used to perform special setup of call argument\n\
4244 registers if a target needs it.\n\
4245 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4246 passed instead of an argument register.\n\
4247 Most ports do not need to implement anything for this hook.",
4253 "This target hook is invoked while generating RTL for a function call,\n\
4254 just after the point where the return reg is copied into a pseudo. It\n\
4255 signals that all the call argument and return registers for the just\n\
4256 emitted call are now no longer in use.\n\
4257 Most ports do not need to implement anything for this hook.",
4262 (strict_argument_naming,
4263 "Define this hook to return @code{true} if the location where a function\n\
4264 argument is passed depends on whether or not it is a named argument.\n\
4266 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4267 is set for varargs and stdarg functions. If this hook returns\n\
4268 @code{true}, the @var{named} argument is always true for named\n\
4269 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4270 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4271 then all arguments are treated as named. Otherwise, all named arguments\n\
4272 except the last are treated as named.\n\
4274 You need not define this hook if it always returns @code{false}.",
4275 bool, (cumulative_args_t ca),
4276 hook_bool_CUMULATIVE_ARGS_false)
4278 /* Returns true if we should use
4279 targetm.calls.setup_incoming_varargs() and/or
4280 targetm.calls.strict_argument_naming(). */
4282 (pretend_outgoing_varargs_named,
4283 "If you need to conditionally change ABIs so that one works with\n\
4284 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4285 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4286 defined, then define this hook to return @code{true} if\n\
4287 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4288 Otherwise, you should not define this hook.",
4289 bool, (cumulative_args_t ca),
4290 default_pretend_outgoing_varargs_named)
4292 /* Given a complex type T, return true if a parameter of type T
4293 should be passed as two scalars. */
4296 "This hook should return true if parameter of type @var{type} are passed\n\
4297 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4298 arguments into the target's word size. Some ABIs require complex arguments\n\
4299 to be split and treated as their individual components. For example, on\n\
4300 AIX64, complex floats should be passed in a pair of floating point\n\
4301 registers, even though a complex float would fit in one 64-bit floating\n\
4304 The default value of this hook is @code{NULL}, which is treated as always\n\
4306 bool, (const_tree type), NULL)
4308 /* Return true if type T, mode MODE, may not be passed in registers,
4309 but must be passed on the stack. */
4310 /* ??? This predicate should be applied strictly after pass-by-reference.
4311 Need audit to verify that this is the case. */
4313 (must_pass_in_stack,
4314 "This target hook should return @code{true} if we should not pass @var{type}\n\
4315 solely in registers. The file @file{expr.h} defines a\n\
4316 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4318 bool, (machine_mode mode, const_tree type),
4319 must_pass_in_stack_var_size_or_pad)
4321 /* Return true if type TYPE, mode MODE, which is passed by reference,
4322 should have the object copy generated by the callee rather than
4323 the caller. It is never called for TYPE requiring constructors. */
4326 "The function argument described by the parameters to this hook is\n\
4327 known to be passed by reference. The hook should return true if the\n\
4328 function argument should be copied by the callee instead of copied\n\
4331 For any argument for which the hook returns true, if it can be\n\
4332 determined that the argument is not modified, then a copy need\n\
4333 not be generated.\n\
4335 The default version of this hook always returns false.",
4337 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4338 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4340 /* Return zero for arguments passed entirely on the stack or entirely
4341 in registers. If passed in both, return the number of bytes passed
4342 in registers; the balance is therefore passed on the stack. */
4345 "This target hook returns the number of bytes at the beginning of an\n\
4346 argument that must be put in registers. The value must be zero for\n\
4347 arguments that are passed entirely in registers or that are entirely\n\
4348 pushed on the stack.\n\
4350 On some machines, certain arguments must be passed partially in\n\
4351 registers and partially in memory. On these machines, typically the\n\
4352 first few words of arguments are passed in registers, and the rest\n\
4353 on the stack. If a multi-word argument (a @code{double} or a\n\
4354 structure) crosses that boundary, its first few words must be passed\n\
4355 in registers and the rest must be pushed. This macro tells the\n\
4356 compiler when this occurs, and how many bytes should go in registers.\n\
4358 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4359 register to be used by the caller for this argument; likewise\n\
4360 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4361 int, (cumulative_args_t cum, machine_mode mode, tree type, bool named),
4362 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
4364 /* Update the state in CA to advance past an argument in the
4365 argument list. The values MODE, TYPE, and NAMED describe that
4368 (function_arg_advance,
4369 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4370 advance past an argument in the argument list. The values @var{mode},\n\
4371 @var{type} and @var{named} describe that argument. Once this is done,\n\
4372 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4373 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4375 This hook need not do anything if the argument in question was passed\n\
4376 on the stack. The compiler knows how to track the amount of stack space\n\
4377 used for arguments without any special help.",
4379 (cumulative_args_t ca, machine_mode mode, const_tree type, bool named),
4380 default_function_arg_advance)
4382 /* Return zero if the argument described by the state of CA should
4383 be placed on a stack, or a hard register in which to store the
4384 argument. The values MODE, TYPE, and NAMED describe that
4388 "Return an RTX indicating whether a function argument is passed in a\n\
4389 register and if so, which register.\n\
4391 The arguments are @var{ca}, which summarizes all the previous\n\
4392 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
4393 the data type of the argument as a tree node or 0 if that is not known\n\
4394 (which happens for C support library functions); and @var{named},\n\
4395 which is @code{true} for an ordinary argument and @code{false} for\n\
4396 nameless arguments that correspond to @samp{@dots{}} in the called\n\
4397 function's prototype. @var{type} can be an incomplete type if a\n\
4398 syntax error has previously occurred.\n\
4400 The return value is usually either a @code{reg} RTX for the hard\n\
4401 register in which to pass the argument, or zero to pass the argument\n\
4404 The return value can be a @code{const_int} which means argument is\n\
4405 passed in a target specific slot with specified number. Target hooks\n\
4406 should be used to store or load argument in such case. See\n\
4407 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4408 for more information.\n\
4410 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4411 used when an argument is passed in multiple locations. The mode of the\n\
4412 @code{parallel} should be the mode of the entire argument. The\n\
4413 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4414 describes where part of the argument is passed. In each\n\
4415 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4416 register in which to pass this part of the argument, and the mode of the\n\
4417 register RTX indicates how large this part of the argument is. The\n\
4418 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4419 the offset in bytes into the entire argument of where this part starts.\n\
4420 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4421 RTX may have a first operand of zero. This indicates that the entire\n\
4422 argument is also stored on the stack.\n\
4424 The last time this hook is called, it is called with @code{MODE ==\n\
4425 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4426 pattern as operands 2 and 3 respectively.\n\
4428 @cindex @file{stdarg.h} and register arguments\n\
4429 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4430 machine where some arguments are usually passed in registers, is to\n\
4431 cause nameless arguments to be passed on the stack instead. This is\n\
4432 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4433 @var{named} is @code{false}.\n\
4435 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4436 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4437 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4438 in the definition of this macro to determine if this argument is of a\n\
4439 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4440 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4441 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4442 defined, the argument will be computed in the stack and then loaded into\n\
4444 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4446 default_function_arg)
4448 /* Likewise, but for machines with register windows. Return the
4449 location where the argument will appear to the callee. */
4451 (function_incoming_arg,
4452 "Define this hook if the target machine has ``register windows'', so\n\
4453 that the register in which a function sees an arguments is not\n\
4454 necessarily the same as the one in which the caller passed the\n\
4457 For such machines, @code{TARGET_FUNCTION_ARG} computes the register in\n\
4458 which the caller passes the value, and\n\
4459 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4460 fashion to tell the function being called where the arguments will\n\
4463 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4464 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4465 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4467 default_function_incoming_arg)
4470 (function_arg_boundary,
4471 "This hook returns the alignment boundary, in bits, of an argument\n\
4472 with the specified mode and type. The default hook returns\n\
4473 @code{PARM_BOUNDARY} for all arguments.",
4474 unsigned int, (machine_mode mode, const_tree type),
4475 default_function_arg_boundary)
4478 (function_arg_round_boundary,
4479 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4480 which is the default value for this hook. You can define this hook to\n\
4481 return a different value if an argument size must be rounded to a larger\n\
4483 unsigned int, (machine_mode mode, const_tree type),
4484 default_function_arg_round_boundary)
4486 /* Return the diagnostic message string if function without a prototype
4487 is not allowed for this 'val' argument; NULL otherwise. */
4489 (invalid_arg_for_unprototyped_fn,
4490 "If defined, this macro returns the diagnostic message when it is\n\
4491 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4492 with prototype @var{typelist}.",
4493 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4494 hook_invalid_arg_for_unprototyped_fn)
4496 /* Return an rtx for the return value location of the function
4497 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4501 Define this to return an RTX representing the place where a function\n\
4502 returns or receives a value of data type @var{ret_type}, a tree node\n\
4503 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4504 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4505 function being called. If @var{outgoing} is false, the hook should\n\
4506 compute the register in which the caller will see the return value.\n\
4507 Otherwise, the hook should return an RTX representing the place where\n\
4508 a function returns a value.\n\
4510 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4511 (Actually, on most machines, scalar values are returned in the same\n\
4512 place regardless of mode.) The value of the expression is usually a\n\
4513 @code{reg} RTX for the hard register where the return value is stored.\n\
4514 The value can also be a @code{parallel} RTX, if the return value is in\n\
4515 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4516 @code{parallel} form. Note that the callee will populate every\n\
4517 location specified in the @code{parallel}, but if the first element of\n\
4518 the @code{parallel} contains the whole return value, callers will use\n\
4519 that element as the canonical location and ignore the others. The m68k\n\
4520 port uses this type of @code{parallel} to return pointers in both\n\
4521 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
4523 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4524 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4525 @var{valtype} is a scalar type.\n\
4527 If the precise function being called is known, @var{func} is a tree\n\
4528 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4529 pointer. This makes it possible to use a different value-returning\n\
4530 convention for specific functions when all their calls are\n\
4533 Some target machines have ``register windows'' so that the register in\n\
4534 which a function returns its value is not the same as the one in which\n\
4535 the caller sees the value. For such machines, you should return\n\
4536 different RTX depending on @var{outgoing}.\n\
4538 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4539 aggregate data types, because these are returned in another way. See\n\
4540 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4541 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4542 default_function_value)
4544 /* Return the rtx for bounds of returned pointer. */
4546 (chkp_function_value_bounds,
4547 "Define this to return an RTX representing the place where a function\n\
4548 returns bounds for returned pointers. Arguments meaning is similar to\n\
4549 @code{TARGET_FUNCTION_VALUE}.",
4550 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4551 default_chkp_function_value_bounds)
4553 /* Return the rtx for the result of a libcall of mode MODE,
4554 calling the function FN_NAME. */
4557 "Define this hook if the back-end needs to know the name of the libcall\n\
4558 function in order to determine where the result should be returned.\n\
4560 The mode of the result is given by @var{mode} and the name of the called\n\
4561 library function is given by @var{fun}. The hook should return an RTX\n\
4562 representing the place where the library function result will be returned.\n\
4564 If this hook is not defined, then LIBCALL_VALUE will be used.",
4565 rtx, (machine_mode mode, const_rtx fun),
4566 default_libcall_value)
4568 /* Return true if REGNO is a possible register number for
4569 a function value as seen by the caller. */
4571 (function_value_regno_p,
4572 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4573 register in which the values of called function may come back.\n\
4575 A register whose use for returning values is limited to serving as the\n\
4576 second of a pair (for a value of type @code{double}, say) need not be\n\
4577 recognized by this target hook.\n\
4579 If the machine has register windows, so that the caller and the called\n\
4580 function use different registers for the return value, this target hook\n\
4581 should recognize only the caller's register numbers.\n\
4583 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4584 bool, (const unsigned int regno),
4585 default_function_value_regno_p)
4587 /* ??? Documenting this hook requires a GFDL license grant. */
4589 (internal_arg_pointer,
4590 "Return an rtx for the argument pointer incoming to the\
4593 default_internal_arg_pointer)
4595 /* Update the current function stack boundary if needed. */
4597 (update_stack_boundary,
4598 "Define this macro to update the current function stack boundary if\n\
4602 /* Handle stack alignment and return an rtx for Dynamic Realign
4603 Argument Pointer if necessary. */
4606 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4607 different argument pointer register is needed to access the function's\n\
4608 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4612 /* Return true if all function parameters should be spilled to the
4615 (allocate_stack_slots_for_args,
4616 "When optimization is disabled, this hook indicates whether or not\n\
4617 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4618 stacks slots for arguments when not optimizing in order to make\n\
4619 debugging easier. However, when a function is declared with\n\
4620 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4621 cannot safely move arguments from the registers in which they are passed\n\
4622 to the stack. Therefore, this hook should return true in general, but\n\
4623 false for naked functions. The default implementation always returns true.",
4625 hook_bool_void_true)
4627 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
4628 is true, then it should be for the callee; otherwise for the caller. */
4631 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4632 targets that may use different static chain locations for different\n\
4633 nested functions. This may be required if the target has function\n\
4634 attributes that affect the calling conventions of the function and\n\
4635 those calling conventions use different static chain locations.\n\
4637 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4639 If the static chain is passed in memory, this hook should be used to\n\
4640 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4641 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4642 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4643 will be at an offset from the frame pointer.\n\
4644 @findex stack_pointer_rtx\n\
4645 @findex frame_pointer_rtx\n\
4646 @findex arg_pointer_rtx\n\
4647 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4648 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4649 to refer to those items.",
4650 rtx, (const_tree fndecl_or_type, bool incoming_p),
4651 default_static_chain)
4653 /* Fill in the trampoline at MEM with a call to FNDECL and a
4654 static chain value of CHAIN. */
4657 "This hook is called to initialize a trampoline.\n\
4658 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4659 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4660 RTX for the static chain value that should be passed to the function\n\
4661 when it is called.\n\
4663 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4664 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4665 from the memory block returned by @code{assemble_trampoline_template}.\n\
4666 Note that the block move need only cover the constant parts of the\n\
4667 trampoline. If the target isolates the variable parts of the trampoline\n\
4668 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4670 If the target requires any other actions, such as flushing caches or\n\
4671 enabling stack execution, these actions should be performed after\n\
4672 initializing the trampoline proper.",
4673 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4674 default_trampoline_init)
4676 /* Adjust the address of the trampoline in a target-specific way. */
4678 (trampoline_adjust_address,
4679 "This hook should perform any machine-specific adjustment in\n\
4680 the address of the trampoline. Its argument contains the address of the\n\
4681 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4682 the address to be used for a function call should be different from the\n\
4683 address at which the template was stored, the different address should\n\
4684 be returned; otherwise @var{addr} should be returned unchanged.\n\
4685 If this hook is not defined, @var{addr} will be used for function calls.",
4686 rtx, (rtx addr), NULL)
4688 /* Return the number of bytes of its own arguments that a function
4689 pops on returning, or 0 if the function pops no arguments and the
4690 caller must therefore pop them all after the function returns. */
4691 /* ??? tm.texi has no types for the parameters. */
4694 "This target hook returns the number of bytes of its own arguments that\n\
4695 a function pops on returning, or 0 if the function pops no arguments\n\
4696 and the caller must therefore pop them all after the function returns.\n\
4698 @var{fundecl} is a C variable whose value is a tree node that describes\n\
4699 the function in question. Normally it is a node of type\n\
4700 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
4701 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4703 @var{funtype} is a C variable whose value is a tree node that\n\
4704 describes the function in question. Normally it is a node of type\n\
4705 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
4706 From this it is possible to obtain the data types of the value and\n\
4707 arguments (if known).\n\
4709 When a call to a library function is being considered, @var{fundecl}\n\
4710 will contain an identifier node for the library function. Thus, if\n\
4711 you need to distinguish among various library functions, you can do so\n\
4712 by their names. Note that ``library function'' in this context means\n\
4713 a function used to perform arithmetic, whose name is known specially\n\
4714 in the compiler and was not mentioned in the C code being compiled.\n\
4716 @var{size} is the number of bytes of arguments passed on the\n\
4717 stack. If a variable number of bytes is passed, it is zero, and\n\
4718 argument popping will always be the responsibility of the calling function.\n\
4720 On the VAX, all functions always pop their arguments, so the definition\n\
4721 of this macro is @var{size}. On the 68000, using the standard\n\
4722 calling convention, no functions pop their arguments, so the value of\n\
4723 the macro is always 0 in this case. But an alternative calling\n\
4724 convention is available in which functions that take a fixed number of\n\
4725 arguments pop them but other functions (such as @code{printf}) pop\n\
4726 nothing (the caller pops all). When this convention is in use,\n\
4727 @var{funtype} is examined to determine whether a function takes a fixed\n\
4728 number of arguments.",
4729 int, (tree fundecl, tree funtype, int size),
4730 default_return_pops_args)
4732 /* Return a mode wide enough to copy any function value that might be
4735 (get_raw_result_mode,
4736 "This target hook returns the mode to be used when accessing raw return\
4737 registers in @code{__builtin_return}. Define this macro if the value\
4738 in @var{reg_raw_mode} is not correct.",
4739 machine_mode, (int regno),
4740 default_get_reg_raw_mode)
4742 /* Return a mode wide enough to copy any argument value that might be
4746 "This target hook returns the mode to be used when accessing raw argument\
4747 registers in @code{__builtin_apply_args}. Define this macro if the value\
4748 in @var{reg_raw_mode} is not correct.",
4749 machine_mode, (int regno),
4750 default_get_reg_raw_mode)
4752 HOOK_VECTOR_END (calls)
4755 (use_pseudo_pic_reg,
4756 "This hook should return 1 in case pseudo register should be created\n\
4757 for pic_offset_table_rtx during function expand.",
4759 hook_bool_void_false)
4763 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
4764 This hook is called at the start of register allocation.",
4768 /* Return the diagnostic message string if conversion from FROMTYPE
4769 to TOTYPE is not allowed, NULL otherwise. */
4771 (invalid_conversion,
4772 "If defined, this macro returns the diagnostic message when it is\n\
4773 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
4774 if validity should be determined by the front end.",
4775 const char *, (const_tree fromtype, const_tree totype),
4776 hook_constcharptr_const_tree_const_tree_null)
4778 /* Return the diagnostic message string if the unary operation OP is
4779 not permitted on TYPE, NULL otherwise. */
4782 "If defined, this macro returns the diagnostic message when it is\n\
4783 invalid to apply operation @var{op} (where unary plus is denoted by\n\
4784 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
4785 if validity should be determined by the front end.",
4786 const char *, (int op, const_tree type),
4787 hook_constcharptr_int_const_tree_null)
4789 /* Return the diagnostic message string if the binary operation OP
4790 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
4793 "If defined, this macro returns the diagnostic message when it is\n\
4794 invalid to apply operation @var{op} to operands of types @var{type1}\n\
4795 and @var{type2}, or @code{NULL} if validity should be determined by\n\
4797 const char *, (int op, const_tree type1, const_tree type2),
4798 hook_constcharptr_int_const_tree_const_tree_null)
4800 /* Return the diagnostic message string if TYPE is not valid as a
4801 function parameter type, NULL otherwise. */
4803 (invalid_parameter_type,
4804 "If defined, this macro returns the diagnostic message when it is\n\
4805 invalid for functions to include parameters of type @var{type},\n\
4806 or @code{NULL} if validity should be determined by\n\
4807 the front end. This is currently used only by the C and C++ front ends.",
4808 const char *, (const_tree type),
4809 hook_constcharptr_const_tree_null)
4811 /* Return the diagnostic message string if TYPE is not valid as a
4812 function return type, NULL otherwise. */
4814 (invalid_return_type,
4815 "If defined, this macro returns the diagnostic message when it is\n\
4816 invalid for functions to have return type @var{type},\n\
4817 or @code{NULL} if validity should be determined by\n\
4818 the front end. This is currently used only by the C and C++ front ends.",
4819 const char *, (const_tree type),
4820 hook_constcharptr_const_tree_null)
4822 /* If values of TYPE are promoted to some other type when used in
4823 expressions (analogous to the integer promotions), return that type,
4824 or NULL_TREE otherwise. */
4827 "If defined, this target hook returns the type to which values of\n\
4828 @var{type} should be promoted when they appear in expressions,\n\
4829 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
4830 front end's normal promotion rules. This hook is useful when there are\n\
4831 target-specific types with special promotion rules.\n\
4832 This is currently used only by the C and C++ front ends.",
4833 tree, (const_tree type),
4834 hook_tree_const_tree_null)
4836 /* Convert EXPR to TYPE, if target-specific types with special conversion
4837 rules are involved. Return the converted expression, or NULL to apply
4838 the standard conversion rules. */
4841 "If defined, this hook returns the result of converting @var{expr} to\n\
4842 @var{type}. It should return the converted expression,\n\
4843 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
4844 This hook is useful when there are target-specific types with special\n\
4845 conversion rules.\n\
4846 This is currently used only by the C and C++ front ends.",
4847 tree, (tree type, tree expr),
4848 hook_tree_tree_tree_null)
4850 /* Change pseudo allocno class calculated by IRA. */
4852 (ira_change_pseudo_allocno_class,
4853 "A target hook which can change allocno class for given pseudo from\n\
4854 allocno class calculated by IRA.\n\
4856 The default version of this target hook always returns given class.",
4857 reg_class_t, (int, reg_class_t),
4858 default_ira_change_pseudo_allocno_class)
4860 /* Return true if we use LRA instead of reload. */
4863 "A target hook which returns true if we use LRA instead of reload pass.\
4864 It means that LRA was ported to the target.\
4866 The default version of this target hook returns always false.",
4870 /* Return register priority of given hard regno for the current target. */
4873 "A target hook which returns the register priority number to which the\
4874 register @var{hard_regno} belongs to. The bigger the number, the\
4875 more preferable the hard register usage (when all other conditions are\
4876 the same). This hook can be used to prefer some hard register over\
4877 others in LRA. For example, some x86-64 register usage needs\
4878 additional prefix which makes instructions longer. The hook can\
4879 return lower priority number for such registers make them less favorable\
4880 and as result making the generated code smaller.\
4882 The default version of this target hook returns always zero.",
4884 default_register_priority)
4886 /* Return true if we need register usage leveling. */
4888 (register_usage_leveling_p,
4889 "A target hook which returns true if we need register usage leveling.\
4890 That means if a few hard registers are equally good for the\
4891 assignment, we choose the least used hard register. The register\
4892 usage leveling may be profitable for some targets. Don't use the\
4893 usage leveling for targets with conditional execution or targets\
4894 with big register files as it hurts if-conversion and cross-jumping\
4897 The default version of this target hook returns always false.",
4899 default_register_usage_leveling_p)
4901 /* Return true if maximal address displacement can be different. */
4903 (different_addr_displacement_p,
4904 "A target hook which returns true if an address with the same structure\
4905 can have different maximal legitimate displacement. For example, the\
4906 displacement can depend on memory mode or on operand combinations in\
4909 The default version of this target hook returns always false.",
4911 default_different_addr_displacement_p)
4913 /* Determine class for spilling pseudos of given mode into registers
4914 instead of memory. */
4917 "This hook defines a class of registers which could be used for spilling\
4918 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
4919 should be used. Not defining this hook is equivalent to returning\
4920 @code{NO_REGS} for all inputs.",
4921 reg_class_t, (reg_class_t, machine_mode),
4926 "This hook defines the machine mode to use for the boolean result of\
4927 conditional store patterns. The ICODE argument is the instruction code\
4928 for the cstore being performed. Not definiting this hook is the same\
4929 as accepting the mode encoded into operand 0 of the cstore expander\
4931 machine_mode, (enum insn_code icode),
4932 default_cstore_mode)
4934 /* True if a structure, union or array with MODE containing FIELD should
4935 be accessed using BLKmode. */
4937 (member_type_forces_blk,
4938 "Return true if a structure, union or array containing @var{field} should\n\
4939 be accessed using @code{BLKMODE}.\n\
4941 If @var{field} is the only field in the structure, @var{mode} is its\n\
4942 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
4943 case where structures of one field would require the structure's mode to\n\
4944 retain the field's mode.\n\
4946 Normally, this is not needed.",
4947 bool, (const_tree field, machine_mode mode),
4948 default_member_type_forces_blk)
4950 /* Return the class for a secondary reload, and fill in extra information. */
4953 "Many machines have some registers that cannot be copied directly to or\n\
4954 from memory or even from other types of registers. An example is the\n\
4955 @samp{MQ} register, which on most machines, can only be copied to or\n\
4956 from general registers, but not memory. Below, we shall be using the\n\
4957 term 'intermediate register' when a move operation cannot be performed\n\
4958 directly, but has to be done by copying the source into the intermediate\n\
4959 register first, and then copying the intermediate register to the\n\
4960 destination. An intermediate register always has the same mode as\n\
4961 source and destination. Since it holds the actual value being copied,\n\
4962 reload might apply optimizations to re-use an intermediate register\n\
4963 and eliding the copy from the source when it can determine that the\n\
4964 intermediate register still holds the required value.\n\
4966 Another kind of secondary reload is required on some machines which\n\
4967 allow copying all registers to and from memory, but require a scratch\n\
4968 register for stores to some memory locations (e.g., those with symbolic\n\
4969 address on the RT, and those with certain symbolic address on the SPARC\n\
4970 when compiling PIC)@. Scratch registers need not have the same mode\n\
4971 as the value being copied, and usually hold a different value than\n\
4972 that being copied. Special patterns in the md file are needed to\n\
4973 describe how the copy is performed with the help of the scratch register;\n\
4974 these patterns also describe the number, register class(es) and mode(s)\n\
4975 of the scratch register(s).\n\
4977 In some cases, both an intermediate and a scratch register are required.\n\
4979 For input reloads, this target hook is called with nonzero @var{in_p},\n\
4980 and @var{x} is an rtx that needs to be copied to a register of class\n\
4981 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
4982 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
4983 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
4985 If copying a register of @var{reload_class} from/to @var{x} requires\n\
4986 an intermediate register, the hook @code{secondary_reload} should\n\
4987 return the register class required for this intermediate register.\n\
4988 If no intermediate register is required, it should return NO_REGS.\n\
4989 If more than one intermediate register is required, describe the one\n\
4990 that is closest in the copy chain to the reload register.\n\
4992 If scratch registers are needed, you also have to describe how to\n\
4993 perform the copy from/to the reload register to/from this\n\
4994 closest intermediate register. Or if no intermediate register is\n\
4995 required, but still a scratch register is needed, describe the\n\
4996 copy from/to the reload register to/from the reload operand @var{x}.\n\
4998 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
4999 in the md file which performs the move. Operands 0 and 1 are the output\n\
5000 and input of this copy, respectively. Operands from operand 2 onward are\n\
5001 for scratch operands. These scratch operands must have a mode, and a\n\
5002 single-register-class\n\
5003 @c [later: or memory]\n\
5004 output constraint.\n\
5006 When an intermediate register is used, the @code{secondary_reload}\n\
5007 hook will be called again to determine how to copy the intermediate\n\
5008 register to/from the reload operand @var{x}, so your hook must also\n\
5009 have code to handle the register class of the intermediate operand.\n\
5011 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5012 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5013 @c and match the constraints of input and output to determine the required\n\
5014 @c alternative. A restriction would be that constraints used to match\n\
5015 @c against reloads registers would have to be written as register class\n\
5016 @c constraints, or we need a new target macro / hook that tells us if an\n\
5017 @c arbitrary constraint can match an unknown register of a given class.\n\
5018 @c Such a macro / hook would also be useful in other places.]\n\
5021 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5022 pseudo-register, which could either be in a hard register or in memory.\n\
5023 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5024 in memory and the hard register number if it is in a register.\n\
5026 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5027 currently not supported. For the time being, you will have to continue\n\
5028 to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5030 @code{copy_cost} also uses this target hook to find out how values are\n\
5031 copied. If you want it to include some extra cost for the need to allocate\n\
5032 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5033 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5034 of the individual moves due to expected fortuitous scheduling and/or special\n\
5035 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5037 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5038 secondary_reload_info *sri),
5039 default_secondary_reload)
5041 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5042 return the class of reg to actually use. */
5044 (preferred_reload_class,
5045 "A target hook that places additional restrictions on the register class\n\
5046 to use when it is necessary to copy value @var{x} into a register in class\n\
5047 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5048 another, smaller class.\n\
5050 The default version of this hook always returns value of @code{rclass} argument.\n\
5052 Sometimes returning a more restrictive class makes better code. For\n\
5053 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5054 for a @samp{moveq} instruction, the value of this macro is always\n\
5055 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5056 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5058 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5059 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5060 loaded into some register class. By returning @code{NO_REGS} you can\n\
5061 force @var{x} into a memory location. For example, rs6000 can load\n\
5062 immediate values into general-purpose registers, but does not have an\n\
5063 instruction for loading an immediate value into a floating-point\n\
5064 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5065 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5066 into any kind of register, code generation will be better if\n\
5067 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5068 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5070 If an insn has pseudos in it after register allocation, reload will go\n\
5071 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5072 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5073 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5074 this feature to discourage usage of 387 registers when math is done in\n\
5075 the SSE registers (and vice versa).",
5077 (rtx x, reg_class_t rclass),
5078 default_preferred_reload_class)
5080 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5083 (preferred_output_reload_class,
5084 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5087 The default version of this hook always returns value of @code{rclass}\n\
5090 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5091 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5093 (rtx x, reg_class_t rclass),
5094 default_preferred_output_reload_class)
5097 (class_likely_spilled_p,
5098 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5099 to registers of class @var{rclass} would likely be spilled because\n\
5100 registers of @var{rclass} are needed for spill registers.\n\
5102 The default version of this target hook returns @code{true} if @var{rclass}\n\
5103 has exactly one register and @code{false} otherwise. On most machines, this\n\
5104 default should be used. For generally register-starved machines, such as\n\
5105 i386, or machines with right register constraints, such as SH, this hook\n\
5106 can be used to avoid excessive spilling.\n\
5108 This hook is also used by some of the global intra-procedural code\n\
5109 transformations to throtle code motion, to avoid increasing register\n\
5111 bool, (reg_class_t rclass),
5112 default_class_likely_spilled_p)
5114 /* Return the maximum number of consecutive registers
5115 needed to represent mode MODE in a register of class RCLASS. */
5118 "A target hook returns the maximum number of consecutive registers\n\
5119 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5121 This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact,\n\
5122 the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5123 @var{mode})} target hook should be the maximum value of\n\
5124 @code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5125 values in the class @var{rclass}.\n\
5127 This target hook helps control the handling of multiple-word values\n\
5128 in the reload pass.\n\
5130 The default version of this target hook returns the size of @var{mode}\n\
5132 unsigned char, (reg_class_t rclass, machine_mode mode),
5133 default_class_max_nregs)
5136 (preferred_rename_class,
5137 "A target hook that places additional preference on the register\
5138 class to use when it is necessary to rename a register in class\
5139 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5140 preferred register class is found or hook @code{preferred_rename_class}\
5141 is not implemented.\
5142 Sometimes returning a more restrictive class makes better code. For\
5143 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5144 smaller than instructions using @code{GENERIC_REGS}. By returning\
5145 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5147 reg_class_t, (reg_class_t rclass),
5148 default_preferred_rename_class)
5150 /* This target hook allows the backend to avoid unsafe substitution
5151 during register allocation. */
5153 (cannot_substitute_mem_equiv_p,
5154 "A target hook which returns @code{true} if @var{subst} can't\n\
5155 substitute safely pseudos with equivalent memory values during\n\
5156 register allocation.\n\
5157 The default version of this target hook returns @code{false}.\n\
5158 On most machines, this default should be used. For generally\n\
5159 machines with non orthogonal register usage for addressing, such\n\
5160 as SH, this hook can be used to avoid excessive spilling.",
5162 hook_bool_rtx_false)
5164 /* This target hook allows the backend to legitimize base plus
5165 displacement addressing. */
5167 (legitimize_address_displacement,
5168 "A target hook which returns @code{true} if *@var{disp} is\n\
5169 legitimezed to valid address displacement with subtracting *@var{offset}\n\
5170 at memory mode @var{mode}.\n\
5171 The default version of this target hook returns @code{false}.\n\
5172 This hook will benefit machines with limited base plus displacement\n\
5174 bool, (rtx *disp, rtx *offset, machine_mode mode),
5175 default_legitimize_address_displacement)
5177 /* This target hook allows the backend to perform additional
5178 processing while initializing for variable expansion. */
5180 (expand_to_rtl_hook,
5181 "This hook is called just before expansion into rtl, allowing the target\n\
5182 to perform additional initializations or analysis before the expansion.\n\
5183 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5184 for use in copying SDmode values between memory and floating point\n\
5185 registers whenever the function being expanded has any SDmode\n\
5190 /* This target hook allows the backend to perform additional
5191 instantiations on rtx that are not actually in insns yet,
5192 but will be later. */
5195 "This hook allows the backend to perform additional instantiations on rtl\n\
5196 that are not actually in any insns yet, but will be later.",
5200 /* Return true if is OK to use a hard register REGNO as scratch register
5203 (hard_regno_scratch_ok,
5204 "This target hook should return @code{true} if it is OK to use a hard register\n\
5205 @var{regno} as scratch reg in peephole2.\n\
5207 One common use of this macro is to prevent using of a register that\n\
5208 is not saved by a prologue in an interrupt handler.\n\
5210 The default version of this hook always returns @code{true}.",
5211 bool, (unsigned int regno),
5212 default_hard_regno_scratch_ok)
5214 /* Return the smallest number of different values for which it is best to
5215 use a jump-table instead of a tree of conditional branches. */
5217 (case_values_threshold,
5218 "This function return the smallest number of different values for which it\n\
5219 is best to use a jump-table instead of a tree of conditional branches.\n\
5220 The default is four for machines with a @code{casesi} instruction and\n\
5221 five otherwise. This is best for most machines.",
5222 unsigned int, (void),
5223 default_case_values_threshold)
5225 /* Retutn true if a function must have and use a frame pointer. */
5227 (frame_pointer_required,
5228 "This target hook should return @code{true} if a function must have and use\n\
5229 a frame pointer. This target hook is called in the reload pass. If its return\n\
5230 value is @code{true} the function will have a frame pointer.\n\
5232 This target hook can in principle examine the current function and decide\n\
5233 according to the facts, but on most machines the constant @code{false} or the\n\
5234 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
5235 to be generated with no frame pointer, and doing so saves some time or space.\n\
5236 Use @code{true} when there is no possible advantage to avoiding a frame\n\
5239 In certain cases, the compiler does not know how to produce valid code\n\
5240 without a frame pointer. The compiler recognizes those cases and\n\
5241 automatically gives the function a frame pointer regardless of what\n\
5242 @code{TARGET_FRAME_POINTER_REQUIRED} returns. You don't need to worry about\n\
5245 In a function that does not require a frame pointer, the frame pointer\n\
5246 register can be allocated for ordinary usage, unless you mark it as a\n\
5247 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
5249 Default return value is @code{false}.",
5251 hook_bool_void_false)
5253 /* Returns true if the compiler is allowed to try to replace register number
5254 from-reg with register number to-reg. */
5257 "This target hook should returns @code{true} if the compiler is allowed to\n\
5258 try to replace register number @var{from_reg} with register number\n\
5259 @var{to_reg}. This target hook need only be defined if @code{ELIMINABLE_REGS}\n\
5260 is defined, and will usually be @code{true}, since most of the cases\n\
5261 preventing register elimination are things that the compiler already\n\
5264 Default return value is @code{true}.",
5265 bool, (const int from_reg, const int to_reg),
5266 hook_bool_const_int_const_int_true)
5268 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
5269 reg_names, and reg_class_contents to account of the vagaries of the
5272 (conditional_register_usage,
5273 "This hook may conditionally modify five variables\n\
5274 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
5275 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
5276 any dependence of these register sets on target flags. The first three\n\
5277 of these are of type @code{char []} (interpreted as Boolean vectors).\n\
5278 @code{global_regs} is a @code{const char *[]}, and\n\
5279 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
5280 called, @code{fixed_regs}, @code{call_used_regs},\n\
5281 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
5282 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
5283 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
5284 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
5285 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
5286 command options have been applied.\n\
5288 @cindex disabling certain registers\n\
5289 @cindex controlling register usage\n\
5290 If the usage of an entire class of registers depends on the target\n\
5291 flags, you may indicate this to GCC by using this macro to modify\n\
5292 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
5293 registers in the classes which should not be used by GCC@. Also make\n\
5294 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
5295 that shouldn't be used.\n\
5297 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
5298 of the insn patterns whose constraints permit this class are\n\
5299 controlled by target switches, then GCC will automatically avoid using\n\
5300 these registers when the target switches are opposed to them.)",
5304 /* Functions specific to the C family of frontends. */
5306 #define HOOK_PREFIX "TARGET_C_"
5307 HOOK_VECTOR (TARGET_C, c)
5309 /* ??? Documenting this hook requires a GFDL license grant. */
5312 "Return machine mode for non-standard constant literal suffix @var{c},\
5313 or VOIDmode if non-standard suffixes are unsupported.",
5314 machine_mode, (char c),
5315 default_mode_for_suffix)
5319 /* Functions specific to the C++ frontend. */
5321 #define HOOK_PREFIX "TARGET_CXX_"
5322 HOOK_VECTOR (TARGET_CXX, cxx)
5324 /* Return the integer type used for guard variables. */
5327 "Define this hook to override the integer type used for guard variables.\n\
5328 These are used to implement one-time construction of static objects. The\n\
5329 default is long_long_integer_type_node.",
5331 default_cxx_guard_type)
5333 /* Return true if only the low bit of the guard should be tested. */
5336 "This hook determines how guard variables are used. It should return\n\
5337 @code{false} (the default) if the first byte should be used. A return value of\n\
5338 @code{true} indicates that only the least significant bit should be used.",
5340 hook_bool_void_false)
5342 /* Returns the size of the array cookie for an array of type. */
5345 "This hook returns the size of the cookie to use when allocating an array\n\
5346 whose elements have the indicated @var{type}. Assumes that it is already\n\
5347 known that a cookie is needed. The default is\n\
5348 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
5349 IA64/Generic C++ ABI@.",
5351 default_cxx_get_cookie_size)
5353 /* Returns true if the element size should be stored in the array cookie. */
5356 "This hook should return @code{true} if the element size should be stored in\n\
5357 array cookies. The default is to return @code{false}.",
5359 hook_bool_void_false)
5361 /* Allows backends to perform additional processing when
5362 deciding if a class should be exported or imported. */
5364 (import_export_class,
5365 "If defined by a backend this hook allows the decision made to export\n\
5366 class @var{type} to be overruled. Upon entry @var{import_export}\n\
5367 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
5368 to be imported and 0 otherwise. This function should return the\n\
5369 modified value and perform any other actions necessary to support the\n\
5370 backend's targeted operating system.",
5371 int, (tree type, int import_export), NULL)
5373 /* Returns true if constructors and destructors return "this". */
5375 (cdtor_returns_this,
5376 "This hook should return @code{true} if constructors and destructors return\n\
5377 the address of the object created/destroyed. The default is to return\n\
5380 hook_bool_void_false)
5382 /* Returns true if the key method for a class can be an inline
5383 function, so long as it is not declared inline in the class
5384 itself. Returning true is the behavior required by the Itanium C++ ABI. */
5386 (key_method_may_be_inline,
5387 "This hook returns true if the key method for a class (i.e., the method\n\
5388 which, if defined in the current translation unit, causes the virtual\n\
5389 table to be emitted) may be an inline function. Under the standard\n\
5390 Itanium C++ ABI the key method may be an inline function so long as\n\
5391 the function is not declared inline in the class definition. Under\n\
5392 some variants of the ABI, an inline function can never be the key\n\
5393 method. The default is to return @code{true}.",
5395 hook_bool_void_true)
5398 (determine_class_data_visibility,
5399 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
5400 or other similar implicit class data object that will be emitted with\
5401 external linkage in this translation unit. No ELF visibility has been\
5402 explicitly specified. If the target needs to specify a visibility\
5403 other than that of the containing class, use this hook to set\
5404 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
5408 /* Returns true (the default) if virtual tables and other
5409 similar implicit class data objects are always COMDAT if they
5410 have external linkage. If this hook returns false, then
5411 class data for classes whose virtual table will be emitted in
5412 only one translation unit will not be COMDAT. */
5414 (class_data_always_comdat,
5415 "This hook returns true (the default) if virtual tables and other\n\
5416 similar implicit class data objects are always COMDAT if they have\n\
5417 external linkage. If this hook returns false, then class data for\n\
5418 classes whose virtual table will be emitted in only one translation\n\
5419 unit will not be COMDAT.",
5421 hook_bool_void_true)
5423 /* Returns true (the default) if the RTTI for the basic types,
5424 which is always defined in the C++ runtime, should be COMDAT;
5425 false if it should not be COMDAT. */
5427 (library_rtti_comdat,
5428 "This hook returns true (the default) if the RTTI information for\n\
5429 the basic types which is defined in the C++ runtime should always\n\
5430 be COMDAT, false if it should not be COMDAT.",
5432 hook_bool_void_true)
5434 /* Returns true if __aeabi_atexit should be used to register static
5438 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
5439 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
5440 is in effect. The default is to return false to use @code{__cxa_atexit}.",
5442 hook_bool_void_false)
5444 /* Returns true if target may use atexit in the same manner as
5445 __cxa_atexit to register static destructors. */
5447 (use_atexit_for_cxa_atexit,
5448 "This hook returns true if the target @code{atexit} function can be used\n\
5449 in the same manner as @code{__cxa_atexit} to register C++ static\n\
5450 destructors. This requires that @code{atexit}-registered functions in\n\
5451 shared libraries are run in the correct order when the libraries are\n\
5452 unloaded. The default is to return false.",
5454 hook_bool_void_false)
5457 (adjust_class_at_definition,
5458 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
5459 been defined. Use this hook to make adjustments to the class (eg, tweak\
5460 visibility or perform any other required target modifications).",
5465 (decl_mangling_context,
5466 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
5467 tree, (const_tree decl),
5468 hook_tree_const_tree_null)
5470 HOOK_VECTOR_END (cxx)
5472 /* Functions and data for emulated TLS support. */
5474 #define HOOK_PREFIX "TARGET_EMUTLS_"
5475 HOOK_VECTOR (TARGET_EMUTLS, emutls)
5477 /* Name of the address and common functions. */
5480 "Contains the name of the helper function that uses a TLS control\n\
5481 object to locate a TLS instance. The default causes libgcc's\n\
5482 emulated TLS helper function to be used.",
5483 const char *, "__builtin___emutls_get_address")
5487 "Contains the name of the helper function that should be used at\n\
5488 program startup to register TLS objects that are implicitly\n\
5489 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
5490 have explicit initializers. The default causes libgcc's emulated TLS\n\
5491 registration function to be used.",
5492 const char *, "__builtin___emutls_register_common")
5494 /* Prefixes for proxy variable and template. */
5497 "Contains the name of the section in which TLS control variables should\n\
5498 be placed. The default of @code{NULL} allows these to be placed in\n\
5504 "Contains the name of the section in which TLS initializers should be\n\
5505 placed. The default of @code{NULL} allows these to be placed in any\n\
5509 /* Prefixes for proxy variable and template. */
5512 "Contains the prefix to be prepended to TLS control variable names.\n\
5513 The default of @code{NULL} uses a target-specific prefix.",
5518 "Contains the prefix to be prepended to TLS initializer objects. The\n\
5519 default of @code{NULL} uses a target-specific prefix.",
5522 /* Function to generate field definitions of the proxy variable. */
5525 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
5526 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
5527 @var{name} should be filled with the structure tag, if the default of\n\
5528 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
5529 for libgcc's emulated TLS function.",
5530 tree, (tree type, tree *name),
5531 default_emutls_var_fields)
5533 /* Function to initialize a proxy variable. */
5536 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
5537 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
5538 is the TLS object and @var{tmpl_addr} is the address of the\n\
5539 initializer. The default initializes libgcc's emulated TLS control object.",
5540 tree, (tree var, tree decl, tree tmpl_addr),
5541 default_emutls_var_init)
5543 /* Whether we are allowed to alter the usual alignment of the
5547 "Specifies whether the alignment of TLS control variable objects is\n\
5548 fixed and should not be increased as some backends may do to optimize\n\
5549 single objects. The default is false.",
5552 /* Whether we can emit debug information for TLS vars. */
5554 (debug_form_tls_address,
5555 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
5556 may be used to describe emulated TLS control objects.",
5559 HOOK_VECTOR_END (emutls)
5562 #define HOOK_PREFIX "TARGET_OPTION_"
5563 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
5565 /* Function to validate the attribute((target(...))) strings. If
5566 the option is validated, the hook should also fill in
5567 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
5570 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
5571 allows setting target-specific options on individual functions.\n\
5572 These function-specific options may differ\n\
5573 from the options specified on the command line. The hook should return\n\
5574 @code{true} if the options are valid.\n\
5576 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
5577 the function declaration to hold a pointer to a target-specific\n\
5578 @code{struct cl_target_option} structure.",
5579 bool, (tree fndecl, tree name, tree args, int flags),
5580 default_target_option_valid_attribute_p)
5582 /* Function to save any extra target state in the target options structure. */
5585 "This hook is called to save any additional target-specific information\n\
5586 in the @code{struct cl_target_option} structure for function-specific\n\
5587 options from the @code{struct gcc_options} structure.\n\
5588 @xref{Option file format}.",
5589 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
5591 /* Function to restore any extra target state from the target options
5595 "This hook is called to restore any additional target-specific\n\
5596 information in the @code{struct cl_target_option} structure for\n\
5597 function-specific options to the @code{struct gcc_options} structure.",
5598 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
5600 /* Function to update target-specific option information after being
5604 "This hook is called to update target-specific information in the\n\
5605 @code{struct cl_target_option} structure after it is streamed in from\n\
5607 void, (struct cl_target_option *ptr), NULL)
5609 /* Function to print any extra target state from the target options
5613 "This hook is called to print any additional target-specific\n\
5614 information in the @code{struct cl_target_option} structure for\n\
5615 function-specific options.",
5616 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
5618 /* Function to parse arguments to be validated for #pragma target, and to
5619 change the state if the options are valid. If the first argument is
5620 NULL, the second argument specifies the default options to use. Return
5621 true if the options are valid, and set the current state. */
5624 "This target hook parses the options for @code{#pragma GCC target}, which\n\
5625 sets the target-specific options for functions that occur later in the\n\
5626 input stream. The options accepted should be the same as those handled by the\n\
5627 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
5628 bool, (tree args, tree pop_target),
5629 default_target_option_pragma_parse)
5631 /* Do option overrides for the target. */
5634 "Sometimes certain combinations of command options do not make sense on\n\
5635 a particular target machine. You can override the hook\n\
5636 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
5637 once just after all the command options have been parsed.\n\
5639 Don't use this hook to turn on various extra optimizations for\n\
5640 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
5642 If you need to do something whenever the optimization level is\n\
5643 changed via the optimize attribute or pragma, see\n\
5644 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
5648 /* This function returns true if DECL1 and DECL2 are versions of the same
5649 function. DECL1 and DECL2 are function versions if and only if they
5650 have the same function signature and different target specific attributes,
5651 that is, they are compiled for different target machines. */
5654 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
5655 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
5656 versions if and only if they have the same function signature and\n\
5657 different target specific attributes, that is, they are compiled for\n\
5658 different target machines.",
5659 bool, (tree decl1, tree decl2),
5660 hook_bool_tree_tree_false)
5662 /* Function to determine if one function can inline another function. */
5664 #define HOOK_PREFIX "TARGET_"
5667 "This target hook returns @code{false} if the @var{caller} function\n\
5668 cannot inline @var{callee}, based on target specific information. By\n\
5669 default, inlining is not allowed if the callee function has function\n\
5670 specific target options and the caller does not use the same options.",
5671 bool, (tree caller, tree callee),
5672 default_target_can_inline_p)
5676 "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.",
5677 void, (tree fndecl),
5680 HOOK_VECTOR_END (target_option)
5682 /* For targets that need to mark extra registers as live on entry to
5683 the function, they should define this target hook and set their
5684 bits in the bitmap passed in. */
5686 (extra_live_on_entry,
5687 "Add any hard registers to @var{regs} that are live on entry to the\n\
5688 function. This hook only needs to be defined to provide registers that\n\
5689 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
5690 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
5691 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
5692 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
5693 void, (bitmap regs),
5696 /* Targets should define this target hook to mark that non-callee clobbers are
5697 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
5700 (call_fusage_contains_non_callee_clobbers,
5701 "Set to true if each call that binds to a local definition explicitly\n\
5702 clobbers or sets all non-fixed registers modified by performing the call.\n\
5703 That is, by the call pattern itself, or by code that might be inserted by the\n\
5704 linker (e.g. stubs, veneers, branch islands), but not including those\n\
5705 modifiable by the callee. The affected registers may be mentioned explicitly\n\
5706 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
5707 The default version of this hook is set to false. The purpose of this hook\n\
5708 is to enable the fipa-ra optimization.",
5712 /* Fill in additional registers set up by prologue into a regset. */
5714 (set_up_by_prologue,
5715 "This hook should add additional registers that are computed by the prologue\
5716 to the hard regset for shrink-wrapping optimization purposes.",
5717 void, (struct hard_reg_set_container *),
5720 /* For targets that have attributes that can affect whether a
5721 function's return statements need checking. For instance a 'naked'
5722 function attribute. */
5725 "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.",
5727 hook_bool_tree_true)
5729 /* Determine the type of unwind info to emit for debugging. */
5732 "This hook defines the mechanism that will be used for describing frame\n\
5733 unwind information to the debugger. Normally the hook will return\n\
5734 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
5735 return @code{UI_NONE} otherwise.\n\
5737 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
5738 is disabled in order to always output DWARF 2 frame information.\n\
5740 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
5741 This will suppress generation of the normal debug frame unwind information.",
5742 enum unwind_info_type, (void),
5743 default_debug_unwind_info)
5745 /* The code parameter should be of type enum rtx_code but this is not
5746 defined at this time. */
5748 (canonicalize_comparison,
5749 "On some machines not all possible comparisons are defined, but you can\n\
5750 convert an invalid comparison into a valid one. For example, the Alpha\n\
5751 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
5752 comparison instead and swap the order of the operands.\n\
5754 On such machines, implement this hook to do any required conversions.\n\
5755 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
5756 are the left and right operands of the comparison, respectively. If\n\
5757 @var{op0_preserve_value} is @code{true} the implementation is not\n\
5758 allowed to change the value of @var{op0} since the value might be used\n\
5759 in RTXs which aren't comparisons. E.g. the implementation is not\n\
5760 allowed to swap operands in that case.\n\
5762 GCC will not assume that the comparison resulting from this macro is\n\
5763 valid but will see if the resulting insn matches a pattern in the\n\
5766 You need not to implement this hook if it would never change the\n\
5767 comparison code or operands.",
5768 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
5769 default_canonicalize_comparison)
5772 (atomic_test_and_set_trueval,
5773 "This value should be set if the result written by\
5774 @code{atomic_test_and_set} is not exactly 1, i.e. the\
5775 @code{bool} @code{true}.",
5778 /* Return an unsigned int representing the alignment (in bits) of the atomic
5779 type which maps to machine MODE. This allows alignment to be overridden
5782 (atomic_align_for_mode,
5783 "If defined, this function returns an appropriate alignment in bits for an\
5784 atomic object of machine_mode @var{mode}. If 0 is returned then the\
5785 default alignment for the specified mode is used. ",
5786 unsigned int, (machine_mode mode),
5790 (atomic_assign_expand_fenv,
5791 "ISO C11 requires atomic compound assignments that may raise floating-point\
5792 exceptions to raise exceptions corresponding to the arithmetic operation\
5793 whose result was successfully stored in a compare-and-exchange sequence. \
5794 This requires code equivalent to calls to @code{feholdexcept},\
5795 @code{feclearexcept} and @code{feupdateenv} to be generated at\
5796 appropriate points in the compare-and-exchange sequence. This hook should\
5797 set @code{*@var{hold}} to an expression equivalent to the call to\
5798 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
5799 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
5800 equivalent to the call to @code{feupdateenv}. The three expressions are\
5801 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
5802 if no code is required in a particular place. The default implementation\
5803 leaves all three expressions as @code{NULL_TREE}. The\
5804 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
5805 as part of the code generated in @code{*@var{update}}.",
5806 void, (tree *hold, tree *clear, tree *update),
5807 default_atomic_assign_expand_fenv)
5809 /* Leave the boolean fields at the end. */
5811 /* True if we can create zeroed data by switching to a BSS section
5812 and then using ASM_OUTPUT_SKIP to allocate the space. */
5814 (have_switchable_bss_sections,
5815 "This flag is true if we can create zeroed data by switching to a BSS\n\
5816 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
5817 This is true on most ELF targets.",
5820 /* True if "native" constructors and destructors are supported,
5821 false if we're using collect2 for the job. */
5824 "This value is true if the target supports some ``native'' method of\n\
5825 collecting constructors and destructors to be run at startup and exit.\n\
5826 It is false if we must use @command{collect2}.",
5829 /* True if thread-local storage is supported. */
5832 "Contains the value true if the target supports thread-local storage.\n\
5833 The default value is false.",
5836 /* True if a small readonly data section is supported. */
5838 (have_srodata_section,
5839 "Contains the value true if the target places read-only\n\
5840 ``small data'' into a separate section. The default value is false.",
5843 /* True if EH frame info sections should be zero-terminated. */
5845 (terminate_dw2_eh_frame_info,
5846 "Contains the value true if the target should add a zero word onto the\n\
5847 end of a Dwarf-2 frame info section when used for exception handling.\n\
5848 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
5852 /* True if #NO_APP should be emitted at the beginning of assembly output. */
5854 (asm_file_start_app_off,
5855 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
5856 printed as the very first line in the assembly file, unless\n\
5857 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
5858 to the empty string, this variable has no effect.) With the normal\n\
5859 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
5860 assembler that it need not bother stripping comments or extra\n\
5861 whitespace from its input. This allows it to work a bit faster.\n\
5863 The default is false. You should not set it to true unless you have\n\
5864 verified that your port does not generate any extra whitespace or\n\
5865 comments that will cause GAS to issue errors in NO_APP mode.",
5868 /* True if output_file_directive should be called for main_input_filename
5869 at the beginning of assembly output. */
5871 (asm_file_start_file_directive,
5872 "If this flag is true, @code{output_file_directive} will be called\n\
5873 for the primary source file, immediately after printing\n\
5874 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
5875 this to be done. The default is false.",
5878 /* Returns true if we should generate exception tables for use with the
5879 ARM EABI. The effects the encoding of function exception specifications. */
5882 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
5883 based unwinding library, and @code{false} on other targets. This effects\n\
5884 the format of unwinding tables, and how the unwinder in entered after\n\
5885 running a cleanup. The default is @code{false}.",
5889 (want_debug_pub_sections,
5890 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
5891 should be emitted. These sections are not used on most platforms, and\
5892 in particular GDB does not use them.",
5897 "True if the @code{DW_AT_comp_dir} attribute should be emitted for each \
5898 compilation unit. This attribute is required for the darwin linker \
5899 to emit debug information.",
5903 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
5904 This usually means it will be run as part of machine-specific reorg.",
5908 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
5909 This usually means it will be run as part of machine-specific reorg.",
5913 (no_register_allocation, "True if register allocation and the passes\n\
5914 following it should not be run. Usually true only for virtual assembler\n\
5918 /* Leave the boolean fields at the end. */
5920 /* Functions related to mode switching. */
5922 #define HOOK_PREFIX "TARGET_MODE_"
5923 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
5927 "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.",
5928 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
5932 "@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}.",
5933 int, (int entity, rtx_insn *insn), NULL)
5937 "@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).",
5938 int, (int entity, int mode, rtx_insn *insn), NULL)
5942 "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.",
5943 int, (int entity), NULL)
5947 "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.",
5948 int, (int entity), NULL)
5952 "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}.",
5953 int, (int entity, int n), NULL)
5955 HOOK_VECTOR_END (mode_switching)
5958 #define HOOK_PREFIX "TARGET_"
5960 #define DEF_TARGET_INSN(NAME, PROTO) \
5961 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
5962 #include "target-insns.def"
5963 #undef DEF_TARGET_INSN
5965 #define DEF_TARGET_INSN(NAME, PROTO) \
5966 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
5967 #include "target-insns.def"
5968 #undef DEF_TARGET_INSN
5970 #define DEF_TARGET_INSN(NAME, PROTO) \
5971 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
5972 #include "target-insns.def"
5973 #undef DEF_TARGET_INSN
5975 /* Close the 'struct gcc_target' definition. */
5976 HOOK_VECTOR_END (C90_EMPTY_HACK)