1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 88, 89, 92-98, 1999 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
44 #include "insn-flags.h"
45 #include "insn-config.h"
46 #include "insn-codes.h"
48 #include "hard-reg-set.h"
56 #define obstack_chunk_alloc xmalloc
57 #define obstack_chunk_free free
58 struct obstack stmt_obstack;
60 /* Assume that case vectors are not pc-relative. */
61 #ifndef CASE_VECTOR_PC_RELATIVE
62 #define CASE_VECTOR_PC_RELATIVE 0
65 /* Filename and line number of last line-number note,
66 whether we actually emitted it or not. */
70 /* Nonzero if within a ({...}) grouping, in which case we must
71 always compute a value for each expr-stmt in case it is the last one. */
73 int expr_stmts_for_value;
75 /* Each time we expand an expression-statement,
76 record the expr's type and its RTL value here. */
78 static tree last_expr_type;
79 static rtx last_expr_value;
81 /* Each time we expand the end of a binding contour (in `expand_end_bindings')
82 and we emit a new NOTE_INSN_BLOCK_END note, we save a pointer to it here.
83 This is used by the `remember_end_note' function to record the endpoint
84 of each generated block in its associated BLOCK node. */
86 static rtx last_block_end_note;
88 /* Number of binding contours started so far in this function. */
90 int block_start_count;
92 /* Nonzero if function being compiled needs to
93 return the address of where it has put a structure value. */
95 extern int current_function_returns_pcc_struct;
97 /* Label that will go on parm cleanup code, if any.
98 Jumping to this label runs cleanup code for parameters, if
99 such code must be run. Following this code is the logical return label. */
101 extern rtx cleanup_label;
103 /* Label that will go on function epilogue.
104 Jumping to this label serves as a "return" instruction
105 on machines which require execution of the epilogue on all returns. */
107 extern rtx return_label;
109 /* Offset to end of allocated area of stack frame.
110 If stack grows down, this is the address of the last stack slot allocated.
111 If stack grows up, this is the address for the next slot. */
112 extern int frame_offset;
114 /* Label to jump back to for tail recursion, or 0 if we have
115 not yet needed one for this function. */
116 extern rtx tail_recursion_label;
118 /* Place after which to insert the tail_recursion_label if we need one. */
119 extern rtx tail_recursion_reentry;
121 /* Location at which to save the argument pointer if it will need to be
122 referenced. There are two cases where this is done: if nonlocal gotos
123 exist, or if vars whose is an offset from the argument pointer will be
124 needed by inner routines. */
126 extern rtx arg_pointer_save_area;
128 /* Chain of all RTL_EXPRs that have insns in them. */
129 extern tree rtl_expr_chain;
131 /* Functions and data structures for expanding case statements. */
133 /* Case label structure, used to hold info on labels within case
134 statements. We handle "range" labels; for a single-value label
135 as in C, the high and low limits are the same.
137 An AVL tree of case nodes is initially created, and later transformed
138 to a list linked via the RIGHT fields in the nodes. Nodes with
139 higher case values are later in the list.
141 Switch statements can be output in one of two forms. A branch table
142 is used if there are more than a few labels and the labels are dense
143 within the range between the smallest and largest case value. If a
144 branch table is used, no further manipulations are done with the case
147 The alternative to the use of a branch table is to generate a series
148 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
149 and PARENT fields to hold a binary tree. Initially the tree is
150 totally unbalanced, with everything on the right. We balance the tree
151 with nodes on the left having lower case values than the parent
152 and nodes on the right having higher values. We then output the tree
157 struct case_node *left; /* Left son in binary tree */
158 struct case_node *right; /* Right son in binary tree; also node chain */
159 struct case_node *parent; /* Parent of node in binary tree */
160 tree low; /* Lowest index value for this label */
161 tree high; /* Highest index value for this label */
162 tree code_label; /* Label to jump to when node matches */
166 typedef struct case_node case_node;
167 typedef struct case_node *case_node_ptr;
169 /* These are used by estimate_case_costs and balance_case_nodes. */
171 /* This must be a signed type, and non-ANSI compilers lack signed char. */
172 static short *cost_table;
173 static int use_cost_table;
175 /* Stack of control and binding constructs we are currently inside.
177 These constructs begin when you call `expand_start_WHATEVER'
178 and end when you call `expand_end_WHATEVER'. This stack records
179 info about how the construct began that tells the end-function
180 what to do. It also may provide information about the construct
181 to alter the behavior of other constructs within the body.
182 For example, they may affect the behavior of C `break' and `continue'.
184 Each construct gets one `struct nesting' object.
185 All of these objects are chained through the `all' field.
186 `nesting_stack' points to the first object (innermost construct).
187 The position of an entry on `nesting_stack' is in its `depth' field.
189 Each type of construct has its own individual stack.
190 For example, loops have `loop_stack'. Each object points to the
191 next object of the same type through the `next' field.
193 Some constructs are visible to `break' exit-statements and others
194 are not. Which constructs are visible depends on the language.
195 Therefore, the data structure allows each construct to be visible
196 or not, according to the args given when the construct is started.
197 The construct is visible if the `exit_label' field is non-null.
198 In that case, the value should be a CODE_LABEL rtx. */
203 struct nesting *next;
208 /* For conds (if-then and if-then-else statements). */
211 /* Label for the end of the if construct.
212 There is none if EXITFLAG was not set
213 and no `else' has been seen yet. */
215 /* Label for the end of this alternative.
216 This may be the end of the if or the next else/elseif. */
222 /* Label at the top of the loop; place to loop back to. */
224 /* Label at the end of the whole construct. */
226 /* Label before a jump that branches to the end of the whole
227 construct. This is where destructors go if any. */
229 /* Label for `continue' statement to jump to;
230 this is in front of the stepper of the loop. */
233 /* For variable binding contours. */
236 /* Sequence number of this binding contour within the function,
237 in order of entry. */
238 int block_start_count;
239 /* Nonzero => value to restore stack to on exit. */
241 /* The NOTE that starts this contour.
242 Used by expand_goto to check whether the destination
243 is within each contour or not. */
245 /* Innermost containing binding contour that has a stack level. */
246 struct nesting *innermost_stack_block;
247 /* List of cleanups to be run on exit from this contour.
248 This is a list of expressions to be evaluated.
249 The TREE_PURPOSE of each link is the ..._DECL node
250 which the cleanup pertains to. */
252 /* List of cleanup-lists of blocks containing this block,
253 as they were at the locus where this block appears.
254 There is an element for each containing block,
255 ordered innermost containing block first.
256 The tail of this list can be 0,
257 if all remaining elements would be empty lists.
258 The element's TREE_VALUE is the cleanup-list of that block,
259 which may be null. */
261 /* Chain of labels defined inside this binding contour.
262 For contours that have stack levels or cleanups. */
263 struct label_chain *label_chain;
264 /* Number of function calls seen, as of start of this block. */
265 int function_call_count;
266 /* Nonzero if this is associated with a EH region. */
267 int exception_region;
268 /* The saved target_temp_slot_level from our outer block.
269 We may reset target_temp_slot_level to be the level of
270 this block, if that is done, target_temp_slot_level
271 reverts to the saved target_temp_slot_level at the very
273 int target_temp_slot_level;
274 /* True if we are currently emitting insns in an area of
275 output code that is controlled by a conditional
276 expression. This is used by the cleanup handling code to
277 generate conditional cleanup actions. */
278 int conditional_code;
279 /* A place to move the start of the exception region for any
280 of the conditional cleanups, must be at the end or after
281 the start of the last unconditional cleanup, and before any
282 conditional branch points. */
283 rtx last_unconditional_cleanup;
284 /* When in a conditional context, this is the specific
285 cleanup list associated with last_unconditional_cleanup,
286 where we place the conditionalized cleanups. */
289 /* For switch (C) or case (Pascal) statements,
290 and also for dummies (see `expand_start_case_dummy'). */
293 /* The insn after which the case dispatch should finally
294 be emitted. Zero for a dummy. */
296 /* A list of case labels; it is first built as an AVL tree.
297 During expand_end_case, this is converted to a list, and may be
298 rearranged into a nearly balanced binary tree. */
299 struct case_node *case_list;
300 /* Label to jump to if no case matches. */
302 /* The expression to be dispatched on. */
304 /* Type that INDEX_EXPR should be converted to. */
306 /* Number of range exprs in case statement. */
308 /* Name of this kind of statement, for warnings. */
309 const char *printname;
310 /* Used to save no_line_numbers till we see the first case label.
311 We set this to -1 when we see the first case label in this
313 int line_number_status;
318 /* Chain of all pending binding contours. */
319 struct nesting *block_stack;
321 /* If any new stacks are added here, add them to POPSTACKS too. */
323 /* Chain of all pending binding contours that restore stack levels
325 struct nesting *stack_block_stack;
327 /* Chain of all pending conditional statements. */
328 struct nesting *cond_stack;
330 /* Chain of all pending loops. */
331 struct nesting *loop_stack;
333 /* Chain of all pending case or switch statements. */
334 struct nesting *case_stack;
336 /* Separate chain including all of the above,
337 chained through the `all' field. */
338 struct nesting *nesting_stack;
340 /* Number of entries on nesting_stack now. */
343 /* Allocate and return a new `struct nesting'. */
345 #define ALLOC_NESTING() \
346 (struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
348 /* Pop the nesting stack element by element until we pop off
349 the element which is at the top of STACK.
350 Update all the other stacks, popping off elements from them
351 as we pop them from nesting_stack. */
353 #define POPSTACK(STACK) \
354 do { struct nesting *target = STACK; \
355 struct nesting *this; \
356 do { this = nesting_stack; \
357 if (loop_stack == this) \
358 loop_stack = loop_stack->next; \
359 if (cond_stack == this) \
360 cond_stack = cond_stack->next; \
361 if (block_stack == this) \
362 block_stack = block_stack->next; \
363 if (stack_block_stack == this) \
364 stack_block_stack = stack_block_stack->next; \
365 if (case_stack == this) \
366 case_stack = case_stack->next; \
367 nesting_depth = nesting_stack->depth - 1; \
368 nesting_stack = this->all; \
369 obstack_free (&stmt_obstack, this); } \
370 while (this != target); } while (0)
372 /* In some cases it is impossible to generate code for a forward goto
373 until the label definition is seen. This happens when it may be necessary
374 for the goto to reset the stack pointer: we don't yet know how to do that.
375 So expand_goto puts an entry on this fixup list.
376 Each time a binding contour that resets the stack is exited,
378 If the target label has now been defined, we can insert the proper code. */
382 /* Points to following fixup. */
383 struct goto_fixup *next;
384 /* Points to the insn before the jump insn.
385 If more code must be inserted, it goes after this insn. */
387 /* The LABEL_DECL that this jump is jumping to, or 0
388 for break, continue or return. */
390 /* The BLOCK for the place where this goto was found. */
392 /* The CODE_LABEL rtx that this is jumping to. */
394 /* Number of binding contours started in current function
395 before the label reference. */
396 int block_start_count;
397 /* The outermost stack level that should be restored for this jump.
398 Each time a binding contour that resets the stack is exited,
399 if the target label is *not* yet defined, this slot is updated. */
401 /* List of lists of cleanup expressions to be run by this goto.
402 There is one element for each block that this goto is within.
403 The tail of this list can be 0,
404 if all remaining elements would be empty.
405 The TREE_VALUE contains the cleanup list of that block as of the
406 time this goto was seen.
407 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
408 tree cleanup_list_list;
411 static struct goto_fixup *goto_fixup_chain;
413 /* Within any binding contour that must restore a stack level,
414 all labels are recorded with a chain of these structures. */
418 /* Points to following fixup. */
419 struct label_chain *next;
424 /* Non-zero if we are using EH to handle cleanus. */
425 static int using_eh_for_cleanups_p = 0;
428 static int n_occurrences PROTO((int, const char *));
429 static void expand_goto_internal PROTO((tree, rtx, rtx));
430 static int expand_fixup PROTO((tree, rtx, rtx));
431 static rtx expand_nl_handler_label PROTO((rtx, rtx));
432 static void expand_nl_goto_receiver PROTO((void));
433 static void expand_nl_goto_receivers PROTO((struct nesting *));
434 static void fixup_gotos PROTO((struct nesting *, rtx, tree,
436 static void expand_null_return_1 PROTO((rtx, int));
437 static void expand_value_return PROTO((rtx));
438 static int tail_recursion_args PROTO((tree, tree));
439 static void expand_cleanups PROTO((tree, tree, int, int));
440 static void check_seenlabel PROTO((void));
441 static void do_jump_if_equal PROTO((rtx, rtx, rtx, int));
442 static int estimate_case_costs PROTO((case_node_ptr));
443 static void group_case_nodes PROTO((case_node_ptr));
444 static void balance_case_nodes PROTO((case_node_ptr *,
446 static int node_has_low_bound PROTO((case_node_ptr, tree));
447 static int node_has_high_bound PROTO((case_node_ptr, tree));
448 static int node_is_bounded PROTO((case_node_ptr, tree));
449 static void emit_jump_if_reachable PROTO((rtx));
450 static void emit_case_nodes PROTO((rtx, case_node_ptr, rtx, tree));
451 static int add_case_node PROTO((tree, tree, tree, tree *));
452 static struct case_node *case_tree2list PROTO((case_node *, case_node *));
455 using_eh_for_cleanups ()
457 using_eh_for_cleanups_p = 1;
463 gcc_obstack_init (&stmt_obstack);
468 init_stmt_for_function ()
470 /* We are not currently within any block, conditional, loop or case. */
472 stack_block_stack = 0;
479 block_start_count = 0;
481 /* No gotos have been expanded yet. */
482 goto_fixup_chain = 0;
484 /* We are not processing a ({...}) grouping. */
485 expr_stmts_for_value = 0;
488 init_eh_for_function ();
495 p->block_stack = block_stack;
496 p->stack_block_stack = stack_block_stack;
497 p->cond_stack = cond_stack;
498 p->loop_stack = loop_stack;
499 p->case_stack = case_stack;
500 p->nesting_stack = nesting_stack;
501 p->nesting_depth = nesting_depth;
502 p->block_start_count = block_start_count;
503 p->last_expr_type = last_expr_type;
504 p->last_expr_value = last_expr_value;
505 p->expr_stmts_for_value = expr_stmts_for_value;
506 p->emit_filename = emit_filename;
507 p->emit_lineno = emit_lineno;
508 p->goto_fixup_chain = goto_fixup_chain;
513 restore_stmt_status (p)
516 block_stack = p->block_stack;
517 stack_block_stack = p->stack_block_stack;
518 cond_stack = p->cond_stack;
519 loop_stack = p->loop_stack;
520 case_stack = p->case_stack;
521 nesting_stack = p->nesting_stack;
522 nesting_depth = p->nesting_depth;
523 block_start_count = p->block_start_count;
524 last_expr_type = p->last_expr_type;
525 last_expr_value = p->last_expr_value;
526 expr_stmts_for_value = p->expr_stmts_for_value;
527 emit_filename = p->emit_filename;
528 emit_lineno = p->emit_lineno;
529 goto_fixup_chain = p->goto_fixup_chain;
530 restore_eh_status (p);
533 /* Emit a no-op instruction. */
540 last_insn = get_last_insn ();
542 && (GET_CODE (last_insn) == CODE_LABEL
543 || (GET_CODE (last_insn) == NOTE
544 && prev_real_insn (last_insn) == 0)))
545 emit_insn (gen_nop ());
548 /* Return the rtx-label that corresponds to a LABEL_DECL,
549 creating it if necessary. */
555 if (TREE_CODE (label) != LABEL_DECL)
558 if (DECL_RTL (label))
559 return DECL_RTL (label);
561 return DECL_RTL (label) = gen_label_rtx ();
564 /* Add an unconditional jump to LABEL as the next sequential instruction. */
570 do_pending_stack_adjust ();
571 emit_jump_insn (gen_jump (label));
575 /* Emit code to jump to the address
576 specified by the pointer expression EXP. */
579 expand_computed_goto (exp)
582 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
584 #ifdef POINTERS_EXTEND_UNSIGNED
585 x = convert_memory_address (Pmode, x);
589 /* Be sure the function is executable. */
590 if (current_function_check_memory_usage)
591 emit_library_call (chkr_check_exec_libfunc, 1,
592 VOIDmode, 1, x, ptr_mode);
594 do_pending_stack_adjust ();
595 emit_indirect_jump (x);
597 current_function_has_computed_jump = 1;
600 /* Handle goto statements and the labels that they can go to. */
602 /* Specify the location in the RTL code of a label LABEL,
603 which is a LABEL_DECL tree node.
605 This is used for the kind of label that the user can jump to with a
606 goto statement, and for alternatives of a switch or case statement.
607 RTL labels generated for loops and conditionals don't go through here;
608 they are generated directly at the RTL level, by other functions below.
610 Note that this has nothing to do with defining label *names*.
611 Languages vary in how they do that and what that even means. */
617 struct label_chain *p;
619 do_pending_stack_adjust ();
620 emit_label (label_rtx (label));
621 if (DECL_NAME (label))
622 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
624 if (stack_block_stack != 0)
626 p = (struct label_chain *) oballoc (sizeof (struct label_chain));
627 p->next = stack_block_stack->data.block.label_chain;
628 stack_block_stack->data.block.label_chain = p;
633 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
634 from nested functions. */
637 declare_nonlocal_label (label)
640 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
642 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
643 LABEL_PRESERVE_P (label_rtx (label)) = 1;
644 if (nonlocal_goto_handler_slots == 0)
646 emit_stack_save (SAVE_NONLOCAL,
647 &nonlocal_goto_stack_level,
648 PREV_INSN (tail_recursion_reentry));
650 nonlocal_goto_handler_slots
651 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
654 /* Generate RTL code for a `goto' statement with target label LABEL.
655 LABEL should be a LABEL_DECL tree node that was or will later be
656 defined with `expand_label'. */
664 /* Check for a nonlocal goto to a containing function. */
665 context = decl_function_context (label);
666 if (context != 0 && context != current_function_decl)
668 struct function *p = find_function_data (context);
669 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
670 rtx temp, handler_slot;
673 /* Find the corresponding handler slot for this label. */
674 handler_slot = p->nonlocal_goto_handler_slots;
675 for (link = p->nonlocal_labels; TREE_VALUE (link) != label;
676 link = TREE_CHAIN (link))
677 handler_slot = XEXP (handler_slot, 1);
678 handler_slot = XEXP (handler_slot, 0);
680 p->has_nonlocal_label = 1;
681 current_function_has_nonlocal_goto = 1;
682 LABEL_REF_NONLOCAL_P (label_ref) = 1;
684 /* Copy the rtl for the slots so that they won't be shared in
685 case the virtual stack vars register gets instantiated differently
686 in the parent than in the child. */
688 #if HAVE_nonlocal_goto
689 if (HAVE_nonlocal_goto)
690 emit_insn (gen_nonlocal_goto (lookup_static_chain (label),
691 copy_rtx (handler_slot),
692 copy_rtx (p->nonlocal_goto_stack_level),
699 /* Restore frame pointer for containing function.
700 This sets the actual hard register used for the frame pointer
701 to the location of the function's incoming static chain info.
702 The non-local goto handler will then adjust it to contain the
703 proper value and reload the argument pointer, if needed. */
704 emit_move_insn (hard_frame_pointer_rtx, lookup_static_chain (label));
706 /* We have now loaded the frame pointer hardware register with
707 the address of that corresponds to the start of the virtual
708 stack vars. So replace virtual_stack_vars_rtx in all
709 addresses we use with stack_pointer_rtx. */
711 /* Get addr of containing function's current nonlocal goto handler,
712 which will do any cleanups and then jump to the label. */
713 addr = copy_rtx (handler_slot);
714 temp = copy_to_reg (replace_rtx (addr, virtual_stack_vars_rtx,
715 hard_frame_pointer_rtx));
717 /* Restore the stack pointer. Note this uses fp just restored. */
718 addr = p->nonlocal_goto_stack_level;
720 addr = replace_rtx (copy_rtx (addr),
721 virtual_stack_vars_rtx,
722 hard_frame_pointer_rtx);
724 emit_stack_restore (SAVE_NONLOCAL, addr, NULL_RTX);
726 /* USE of hard_frame_pointer_rtx added for consistency; not clear if
728 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
729 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
730 emit_indirect_jump (temp);
734 expand_goto_internal (label, label_rtx (label), NULL_RTX);
737 /* Generate RTL code for a `goto' statement with target label BODY.
738 LABEL should be a LABEL_REF.
739 LAST_INSN, if non-0, is the rtx we should consider as the last
740 insn emitted (for the purposes of cleaning up a return). */
743 expand_goto_internal (body, label, last_insn)
748 struct nesting *block;
751 if (GET_CODE (label) != CODE_LABEL)
754 /* If label has already been defined, we can tell now
755 whether and how we must alter the stack level. */
757 if (PREV_INSN (label) != 0)
759 /* Find the innermost pending block that contains the label.
760 (Check containment by comparing insn-uids.)
761 Then restore the outermost stack level within that block,
762 and do cleanups of all blocks contained in it. */
763 for (block = block_stack; block; block = block->next)
765 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
767 if (block->data.block.stack_level != 0)
768 stack_level = block->data.block.stack_level;
769 /* Execute the cleanups for blocks we are exiting. */
770 if (block->data.block.cleanups != 0)
772 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
773 do_pending_stack_adjust ();
779 /* Ensure stack adjust isn't done by emit_jump, as this
780 would clobber the stack pointer. This one should be
781 deleted as dead by flow. */
782 clear_pending_stack_adjust ();
783 do_pending_stack_adjust ();
784 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
787 if (body != 0 && DECL_TOO_LATE (body))
788 error ("jump to `%s' invalidly jumps into binding contour",
789 IDENTIFIER_POINTER (DECL_NAME (body)));
791 /* Label not yet defined: may need to put this goto
792 on the fixup list. */
793 else if (! expand_fixup (body, label, last_insn))
795 /* No fixup needed. Record that the label is the target
796 of at least one goto that has no fixup. */
798 TREE_ADDRESSABLE (body) = 1;
804 /* Generate if necessary a fixup for a goto
805 whose target label in tree structure (if any) is TREE_LABEL
806 and whose target in rtl is RTL_LABEL.
808 If LAST_INSN is nonzero, we pretend that the jump appears
809 after insn LAST_INSN instead of at the current point in the insn stream.
811 The fixup will be used later to insert insns just before the goto.
812 Those insns will restore the stack level as appropriate for the
813 target label, and will (in the case of C++) also invoke any object
814 destructors which have to be invoked when we exit the scopes which
815 are exited by the goto.
817 Value is nonzero if a fixup is made. */
820 expand_fixup (tree_label, rtl_label, last_insn)
825 struct nesting *block, *end_block;
827 /* See if we can recognize which block the label will be output in.
828 This is possible in some very common cases.
829 If we succeed, set END_BLOCK to that block.
830 Otherwise, set it to 0. */
833 && (rtl_label == cond_stack->data.cond.endif_label
834 || rtl_label == cond_stack->data.cond.next_label))
835 end_block = cond_stack;
836 /* If we are in a loop, recognize certain labels which
837 are likely targets. This reduces the number of fixups
838 we need to create. */
840 && (rtl_label == loop_stack->data.loop.start_label
841 || rtl_label == loop_stack->data.loop.end_label
842 || rtl_label == loop_stack->data.loop.continue_label))
843 end_block = loop_stack;
847 /* Now set END_BLOCK to the binding level to which we will return. */
851 struct nesting *next_block = end_block->all;
854 /* First see if the END_BLOCK is inside the innermost binding level.
855 If so, then no cleanups or stack levels are relevant. */
856 while (next_block && next_block != block)
857 next_block = next_block->all;
862 /* Otherwise, set END_BLOCK to the innermost binding level
863 which is outside the relevant control-structure nesting. */
864 next_block = block_stack->next;
865 for (block = block_stack; block != end_block; block = block->all)
866 if (block == next_block)
867 next_block = next_block->next;
868 end_block = next_block;
871 /* Does any containing block have a stack level or cleanups?
872 If not, no fixup is needed, and that is the normal case
873 (the only case, for standard C). */
874 for (block = block_stack; block != end_block; block = block->next)
875 if (block->data.block.stack_level != 0
876 || block->data.block.cleanups != 0)
879 if (block != end_block)
881 /* Ok, a fixup is needed. Add a fixup to the list of such. */
882 struct goto_fixup *fixup
883 = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
884 /* In case an old stack level is restored, make sure that comes
885 after any pending stack adjust. */
886 /* ?? If the fixup isn't to come at the present position,
887 doing the stack adjust here isn't useful. Doing it with our
888 settings at that location isn't useful either. Let's hope
891 do_pending_stack_adjust ();
892 fixup->target = tree_label;
893 fixup->target_rtl = rtl_label;
895 /* Create a BLOCK node and a corresponding matched set of
896 NOTE_INSN_BEGIN_BLOCK and NOTE_INSN_END_BLOCK notes at
897 this point. The notes will encapsulate any and all fixup
898 code which we might later insert at this point in the insn
899 stream. Also, the BLOCK node will be the parent (i.e. the
900 `SUPERBLOCK') of any other BLOCK nodes which we might create
901 later on when we are expanding the fixup code.
903 Note that optimization passes (including expand_end_loop)
904 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
908 register rtx original_before_jump
909 = last_insn ? last_insn : get_last_insn ();
914 start = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
915 fixup->before_jump = emit_note (NULL_PTR, NOTE_INSN_DELETED);
916 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
917 fixup->context = poplevel (1, 0, 0); /* Create the BLOCK node now! */
919 emit_insns_after (start, original_before_jump);
922 fixup->block_start_count = block_start_count;
923 fixup->stack_level = 0;
924 fixup->cleanup_list_list
925 = ((block->data.block.outer_cleanups
926 || block->data.block.cleanups)
927 ? tree_cons (NULL_TREE, block->data.block.cleanups,
928 block->data.block.outer_cleanups)
930 fixup->next = goto_fixup_chain;
931 goto_fixup_chain = fixup;
939 /* Expand any needed fixups in the outputmost binding level of the
940 function. FIRST_INSN is the first insn in the function. */
943 expand_fixups (first_insn)
946 fixup_gotos (NULL_PTR, NULL_RTX, NULL_TREE, first_insn, 0);
949 /* When exiting a binding contour, process all pending gotos requiring fixups.
950 THISBLOCK is the structure that describes the block being exited.
951 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
952 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
953 FIRST_INSN is the insn that began this contour.
955 Gotos that jump out of this contour must restore the
956 stack level and do the cleanups before actually jumping.
958 DONT_JUMP_IN nonzero means report error there is a jump into this
959 contour from before the beginning of the contour.
960 This is also done if STACK_LEVEL is nonzero. */
963 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
964 struct nesting *thisblock;
970 register struct goto_fixup *f, *prev;
972 /* F is the fixup we are considering; PREV is the previous one. */
973 /* We run this loop in two passes so that cleanups of exited blocks
974 are run first, and blocks that are exited are marked so
977 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
979 /* Test for a fixup that is inactive because it is already handled. */
980 if (f->before_jump == 0)
982 /* Delete inactive fixup from the chain, if that is easy to do. */
984 prev->next = f->next;
986 /* Has this fixup's target label been defined?
987 If so, we can finalize it. */
988 else if (PREV_INSN (f->target_rtl) != 0)
990 register rtx cleanup_insns;
992 /* Get the first non-label after the label
993 this goto jumps to. If that's before this scope begins,
994 we don't have a jump into the scope. */
995 rtx after_label = f->target_rtl;
996 while (after_label != 0 && GET_CODE (after_label) == CODE_LABEL)
997 after_label = NEXT_INSN (after_label);
999 /* If this fixup jumped into this contour from before the beginning
1000 of this contour, report an error. */
1001 /* ??? Bug: this does not detect jumping in through intermediate
1002 blocks that have stack levels or cleanups.
1003 It detects only a problem with the innermost block
1004 around the label. */
1006 && (dont_jump_in || stack_level || cleanup_list)
1007 /* If AFTER_LABEL is 0, it means the jump goes to the end
1008 of the rtl, which means it jumps into this scope. */
1009 && (after_label == 0
1010 || INSN_UID (first_insn) < INSN_UID (after_label))
1011 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
1012 && ! DECL_ERROR_ISSUED (f->target))
1014 error_with_decl (f->target,
1015 "label `%s' used before containing binding contour");
1016 /* Prevent multiple errors for one label. */
1017 DECL_ERROR_ISSUED (f->target) = 1;
1020 /* We will expand the cleanups into a sequence of their own and
1021 then later on we will attach this new sequence to the insn
1022 stream just ahead of the actual jump insn. */
1026 /* Temporarily restore the lexical context where we will
1027 logically be inserting the fixup code. We do this for the
1028 sake of getting the debugging information right. */
1031 set_block (f->context);
1033 /* Expand the cleanups for blocks this jump exits. */
1034 if (f->cleanup_list_list)
1037 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1038 /* Marked elements correspond to blocks that have been closed.
1039 Do their cleanups. */
1040 if (TREE_ADDRESSABLE (lists)
1041 && TREE_VALUE (lists) != 0)
1043 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1044 /* Pop any pushes done in the cleanups,
1045 in case function is about to return. */
1046 do_pending_stack_adjust ();
1050 /* Restore stack level for the biggest contour that this
1051 jump jumps out of. */
1053 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1055 /* Finish up the sequence containing the insns which implement the
1056 necessary cleanups, and then attach that whole sequence to the
1057 insn stream just ahead of the actual jump insn. Attaching it
1058 at that point insures that any cleanups which are in fact
1059 implicit C++ object destructions (which must be executed upon
1060 leaving the block) appear (to the debugger) to be taking place
1061 in an area of the generated code where the object(s) being
1062 destructed are still "in scope". */
1064 cleanup_insns = get_insns ();
1068 emit_insns_after (cleanup_insns, f->before_jump);
1075 /* For any still-undefined labels, do the cleanups for this block now.
1076 We must do this now since items in the cleanup list may go out
1077 of scope when the block ends. */
1078 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1079 if (f->before_jump != 0
1080 && PREV_INSN (f->target_rtl) == 0
1081 /* Label has still not appeared. If we are exiting a block with
1082 a stack level to restore, that started before the fixup,
1083 mark this stack level as needing restoration
1084 when the fixup is later finalized. */
1086 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1087 means the label is undefined. That's erroneous, but possible. */
1088 && (thisblock->data.block.block_start_count
1089 <= f->block_start_count))
1091 tree lists = f->cleanup_list_list;
1094 for (; lists; lists = TREE_CHAIN (lists))
1095 /* If the following elt. corresponds to our containing block
1096 then the elt. must be for this block. */
1097 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1101 set_block (f->context);
1102 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1103 do_pending_stack_adjust ();
1104 cleanup_insns = get_insns ();
1107 if (cleanup_insns != 0)
1109 = emit_insns_after (cleanup_insns, f->before_jump);
1111 f->cleanup_list_list = TREE_CHAIN (lists);
1115 f->stack_level = stack_level;
1119 /* Return the number of times character C occurs in string S. */
1121 n_occurrences (c, s)
1131 /* Generate RTL for an asm statement (explicit assembler code).
1132 BODY is a STRING_CST node containing the assembler code text,
1133 or an ADDR_EXPR containing a STRING_CST. */
1139 if (current_function_check_memory_usage)
1141 error ("`asm' cannot be used with `-fcheck-memory-usage'");
1145 if (TREE_CODE (body) == ADDR_EXPR)
1146 body = TREE_OPERAND (body, 0);
1148 emit_insn (gen_rtx_ASM_INPUT (VOIDmode,
1149 TREE_STRING_POINTER (body)));
1153 /* Generate RTL for an asm statement with arguments.
1154 STRING is the instruction template.
1155 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1156 Each output or input has an expression in the TREE_VALUE and
1157 a constraint-string in the TREE_PURPOSE.
1158 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1159 that is clobbered by this insn.
1161 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1162 Some elements of OUTPUTS may be replaced with trees representing temporary
1163 values. The caller should copy those temporary values to the originally
1166 VOL nonzero means the insn is volatile; don't optimize it. */
1169 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1170 tree string, outputs, inputs, clobbers;
1175 rtvec argvec, constraints;
1177 int ninputs = list_length (inputs);
1178 int noutputs = list_length (outputs);
1183 /* Vector of RTX's of evaluated output operands. */
1184 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1185 int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
1186 rtx *real_output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1187 enum machine_mode *inout_mode
1188 = (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
1189 /* The insn we have emitted. */
1192 /* An ASM with no outputs needs to be treated as volatile, for now. */
1196 if (current_function_check_memory_usage)
1198 error ("`asm' cannot be used with `-fcheck-memory-usage'");
1202 /* Count the number of meaningful clobbered registers, ignoring what
1203 we would ignore later. */
1205 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1207 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1208 i = decode_reg_name (regname);
1209 if (i >= 0 || i == -4)
1212 error ("unknown register name `%s' in `asm'", regname);
1217 /* Check that the number of alternatives is constant across all
1219 if (outputs || inputs)
1221 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1222 int nalternatives = n_occurrences (',', TREE_STRING_POINTER (tmp));
1225 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1227 error ("too many alternatives in `asm'");
1234 char *constraint = TREE_STRING_POINTER (TREE_PURPOSE (tmp));
1235 if (n_occurrences (',', constraint) != nalternatives)
1237 error ("operand constraints for `asm' differ in number of alternatives");
1240 if (TREE_CHAIN (tmp))
1241 tmp = TREE_CHAIN (tmp);
1243 tmp = next, next = 0;
1247 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1249 tree val = TREE_VALUE (tail);
1250 tree type = TREE_TYPE (val);
1259 /* If there's an erroneous arg, emit no insn. */
1260 if (TREE_TYPE (val) == error_mark_node)
1263 /* Make sure constraint has `=' and does not have `+'. Also, see
1264 if it allows any register. Be liberal on the latter test, since
1265 the worst that happens if we get it wrong is we issue an error
1268 c_len = TREE_STRING_LENGTH (TREE_PURPOSE (tail)) - 1;
1269 constraint = TREE_STRING_POINTER (TREE_PURPOSE (tail));
1271 /* Allow the `=' or `+' to not be at the beginning of the string,
1272 since it wasn't explicitly documented that way, and there is a
1273 large body of code that puts it last. Swap the character to
1274 the front, so as not to uglify any place else. */
1278 if ((p = strchr (constraint, '=')) != NULL)
1280 if ((p = strchr (constraint, '+')) != NULL)
1283 error ("output operand constraint lacks `='");
1287 if (p != constraint)
1290 bcopy (constraint, constraint+1, p-constraint);
1293 warning ("output constraint `%c' for operand %d is not at the beginning", j, i);
1296 is_inout = constraint[0] == '+';
1297 /* Replace '+' with '='. */
1298 constraint[0] = '=';
1299 /* Make sure we can specify the matching operand. */
1300 if (is_inout && i > 9)
1302 error ("output operand constraint %d contains `+'", i);
1306 for (j = 1; j < c_len; j++)
1307 switch (constraint[j])
1311 error ("operand constraint contains '+' or '=' at illegal position.");
1315 if (i + 1 == ninputs + noutputs)
1317 error ("`%%' constraint used with last operand");
1322 case '?': case '!': case '*': case '&':
1323 case 'E': case 'F': case 'G': case 'H':
1324 case 's': case 'i': case 'n':
1325 case 'I': case 'J': case 'K': case 'L': case 'M':
1326 case 'N': case 'O': case 'P': case ',':
1327 #ifdef EXTRA_CONSTRAINT
1328 case 'Q': case 'R': case 'S': case 'T': case 'U':
1332 case '0': case '1': case '2': case '3': case '4':
1333 case '5': case '6': case '7': case '8': case '9':
1334 error ("matching constraint not valid in output operand");
1337 case 'V': case 'm': case 'o':
1342 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1343 excepting those that expand_call created. So match memory
1359 /* If an output operand is not a decl or indirect ref and our constraint
1360 allows a register, make a temporary to act as an intermediate.
1361 Make the asm insn write into that, then our caller will copy it to
1362 the real output operand. Likewise for promoted variables. */
1364 real_output_rtx[i] = NULL_RTX;
1365 if ((TREE_CODE (val) == INDIRECT_REF
1367 || (TREE_CODE_CLASS (TREE_CODE (val)) == 'd'
1368 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1369 && ! (GET_CODE (DECL_RTL (val)) == REG
1370 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1375 mark_addressable (TREE_VALUE (tail));
1378 = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode,
1379 EXPAND_MEMORY_USE_WO);
1381 if (! allows_reg && GET_CODE (output_rtx[i]) != MEM)
1382 error ("output number %d not directly addressable", i);
1383 if (! allows_mem && GET_CODE (output_rtx[i]) == MEM)
1385 real_output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1386 output_rtx[i] = gen_reg_rtx (GET_MODE (output_rtx[i]));
1388 emit_move_insn (output_rtx[i], real_output_rtx[i]);
1393 output_rtx[i] = assign_temp (type, 0, 0, 0);
1394 TREE_VALUE (tail) = make_tree (type, output_rtx[i]);
1399 inout_mode[ninout] = TYPE_MODE (TREE_TYPE (TREE_VALUE (tail)));
1400 inout_opnum[ninout++] = i;
1405 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1407 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1411 /* Make vectors for the expression-rtx and constraint strings. */
1413 argvec = rtvec_alloc (ninputs);
1414 constraints = rtvec_alloc (ninputs);
1416 body = gen_rtx_ASM_OPERANDS (VOIDmode,
1417 TREE_STRING_POINTER (string), "", 0, argvec,
1418 constraints, filename, line);
1420 MEM_VOLATILE_P (body) = vol;
1422 /* Eval the inputs and put them into ARGVEC.
1423 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1426 for (tail = inputs; tail; tail = TREE_CHAIN (tail))
1429 int allows_reg = 0, allows_mem = 0;
1430 char *constraint, *orig_constraint;
1434 /* If there's an erroneous arg, emit no insn,
1435 because the ASM_INPUT would get VOIDmode
1436 and that could cause a crash in reload. */
1437 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1440 /* ??? Can this happen, and does the error message make any sense? */
1441 if (TREE_PURPOSE (tail) == NULL_TREE)
1443 error ("hard register `%s' listed as input operand to `asm'",
1444 TREE_STRING_POINTER (TREE_VALUE (tail)) );
1448 c_len = TREE_STRING_LENGTH (TREE_PURPOSE (tail)) - 1;
1449 constraint = TREE_STRING_POINTER (TREE_PURPOSE (tail));
1450 orig_constraint = constraint;
1452 /* Make sure constraint has neither `=', `+', nor '&'. */
1454 for (j = 0; j < c_len; j++)
1455 switch (constraint[j])
1457 case '+': case '=': case '&':
1458 if (constraint == orig_constraint)
1460 error ("input operand constraint contains `%c'", constraint[j]);
1466 if (constraint == orig_constraint
1467 && i + 1 == ninputs - ninout)
1469 error ("`%%' constraint used with last operand");
1474 case 'V': case 'm': case 'o':
1479 case '?': case '!': case '*':
1480 case 'E': case 'F': case 'G': case 'H': case 'X':
1481 case 's': case 'i': case 'n':
1482 case 'I': case 'J': case 'K': case 'L': case 'M':
1483 case 'N': case 'O': case 'P': case ',':
1484 #ifdef EXTRA_CONSTRAINT
1485 case 'Q': case 'R': case 'S': case 'T': case 'U':
1489 /* Whether or not a numeric constraint allows a register is
1490 decided by the matching constraint, and so there is no need
1491 to do anything special with them. We must handle them in
1492 the default case, so that we don't unnecessarily force
1493 operands to memory. */
1494 case '0': case '1': case '2': case '3': case '4':
1495 case '5': case '6': case '7': case '8': case '9':
1496 if (constraint[j] >= '0' + noutputs)
1499 ("matching constraint references invalid operand number");
1503 /* Try and find the real constraint for this dup. */
1504 if ((j == 0 && c_len == 1)
1505 || (j == 1 && c_len == 2 && constraint[0] == '%'))
1508 for (j = constraint[j] - '0'; j > 0; --j)
1511 c_len = TREE_STRING_LENGTH (TREE_PURPOSE (o)) - 1;
1512 constraint = TREE_STRING_POINTER (TREE_PURPOSE (o));
1517 /* ... fall through ... */
1530 if (! allows_reg && allows_mem)
1531 mark_addressable (TREE_VALUE (tail));
1533 op = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1535 if (asm_operand_ok (op, constraint) <= 0)
1538 op = force_reg (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))), op);
1539 else if (!allows_mem)
1540 warning ("asm operand %d probably doesn't match constraints", i);
1541 else if (CONSTANT_P (op))
1542 op = force_const_mem (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1544 else if (GET_CODE (op) == REG
1545 || GET_CODE (op) == SUBREG
1546 || GET_CODE (op) == CONCAT)
1548 tree type = TREE_TYPE (TREE_VALUE (tail));
1549 rtx memloc = assign_temp (type, 1, 1, 1);
1551 emit_move_insn (memloc, op);
1554 else if (GET_CODE (op) == MEM && MEM_VOLATILE_P (op))
1555 /* We won't recognize volatile memory as available a
1556 memory_operand at this point. Ignore it. */
1558 else if (queued_subexp_p (op))
1561 /* ??? Leave this only until we have experience with what
1562 happens in combine and elsewhere when constraints are
1564 warning ("asm operand %d probably doesn't match constraints", i);
1566 XVECEXP (body, 3, i) = op;
1568 XVECEXP (body, 4, i) /* constraints */
1569 = gen_rtx_ASM_INPUT (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1574 /* Protect all the operands from the queue,
1575 now that they have all been evaluated. */
1577 for (i = 0; i < ninputs - ninout; i++)
1578 XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
1580 for (i = 0; i < noutputs; i++)
1581 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1583 /* For in-out operands, copy output rtx to input rtx. */
1584 for (i = 0; i < ninout; i++)
1586 static char match[9+1][2]
1587 = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
1588 int j = inout_opnum[i];
1590 XVECEXP (body, 3, ninputs - ninout + i) /* argvec */
1592 XVECEXP (body, 4, ninputs - ninout + i) /* constraints */
1593 = gen_rtx_ASM_INPUT (inout_mode[j], match[j]);
1596 /* Now, for each output, construct an rtx
1597 (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
1598 ARGVEC CONSTRAINTS))
1599 If there is more than one, put them inside a PARALLEL. */
1601 if (noutputs == 1 && nclobbers == 0)
1603 XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
1604 insn = emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1606 else if (noutputs == 0 && nclobbers == 0)
1608 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1609 insn = emit_insn (body);
1615 if (num == 0) num = 1;
1616 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1618 /* For each output operand, store a SET. */
1620 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1622 XVECEXP (body, 0, i)
1623 = gen_rtx_SET (VOIDmode,
1625 gen_rtx_ASM_OPERANDS (VOIDmode,
1626 TREE_STRING_POINTER (string),
1627 TREE_STRING_POINTER (TREE_PURPOSE (tail)),
1628 i, argvec, constraints,
1630 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1633 /* If there are no outputs (but there are some clobbers)
1634 store the bare ASM_OPERANDS into the PARALLEL. */
1637 XVECEXP (body, 0, i++) = obody;
1639 /* Store (clobber REG) for each clobbered register specified. */
1641 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1643 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1644 int j = decode_reg_name (regname);
1648 if (j == -3) /* `cc', which is not a register */
1651 if (j == -4) /* `memory', don't cache memory across asm */
1653 XVECEXP (body, 0, i++)
1654 = gen_rtx_CLOBBER (VOIDmode,
1655 gen_rtx_MEM (BLKmode,
1656 gen_rtx_SCRATCH (VOIDmode)));
1660 /* Ignore unknown register, error already signaled. */
1664 /* Use QImode since that's guaranteed to clobber just one reg. */
1665 XVECEXP (body, 0, i++)
1666 = gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (QImode, j));
1669 insn = emit_insn (body);
1672 /* For any outputs that needed reloading into registers, spill them
1673 back to where they belong. */
1674 for (i = 0; i < noutputs; ++i)
1675 if (real_output_rtx[i])
1676 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1681 /* Generate RTL to evaluate the expression EXP
1682 and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
1685 expand_expr_stmt (exp)
1688 /* If -W, warn about statements with no side effects,
1689 except for an explicit cast to void (e.g. for assert()), and
1690 except inside a ({...}) where they may be useful. */
1691 if (expr_stmts_for_value == 0 && exp != error_mark_node)
1693 if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
1694 && !(TREE_CODE (exp) == CONVERT_EXPR
1695 && TREE_TYPE (exp) == void_type_node))
1696 warning_with_file_and_line (emit_filename, emit_lineno,
1697 "statement with no effect");
1698 else if (warn_unused)
1699 warn_if_unused_value (exp);
1702 /* If EXP is of function type and we are expanding statements for
1703 value, convert it to pointer-to-function. */
1704 if (expr_stmts_for_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
1705 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
1707 last_expr_type = TREE_TYPE (exp);
1708 last_expr_value = expand_expr (exp,
1709 (expr_stmts_for_value
1710 ? NULL_RTX : const0_rtx),
1713 /* If all we do is reference a volatile value in memory,
1714 copy it to a register to be sure it is actually touched. */
1715 if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
1716 && TREE_THIS_VOLATILE (exp))
1718 if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
1720 else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
1721 copy_to_reg (last_expr_value);
1724 rtx lab = gen_label_rtx ();
1726 /* Compare the value with itself to reference it. */
1727 emit_cmp_and_jump_insns (last_expr_value, last_expr_value, EQ,
1728 expand_expr (TYPE_SIZE (last_expr_type),
1729 NULL_RTX, VOIDmode, 0),
1731 TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT,
1737 /* If this expression is part of a ({...}) and is in memory, we may have
1738 to preserve temporaries. */
1739 preserve_temp_slots (last_expr_value);
1741 /* Free any temporaries used to evaluate this expression. Any temporary
1742 used as a result of this expression will already have been preserved
1749 /* Warn if EXP contains any computations whose results are not used.
1750 Return 1 if a warning is printed; 0 otherwise. */
1753 warn_if_unused_value (exp)
1756 if (TREE_USED (exp))
1759 switch (TREE_CODE (exp))
1761 case PREINCREMENT_EXPR:
1762 case POSTINCREMENT_EXPR:
1763 case PREDECREMENT_EXPR:
1764 case POSTDECREMENT_EXPR:
1769 case METHOD_CALL_EXPR:
1771 case TRY_CATCH_EXPR:
1772 case WITH_CLEANUP_EXPR:
1774 /* We don't warn about COND_EXPR because it may be a useful
1775 construct if either arm contains a side effect. */
1780 /* For a binding, warn if no side effect within it. */
1781 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1784 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1786 case TRUTH_ORIF_EXPR:
1787 case TRUTH_ANDIF_EXPR:
1788 /* In && or ||, warn if 2nd operand has no side effect. */
1789 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1792 if (TREE_NO_UNUSED_WARNING (exp))
1794 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
1796 /* Let people do `(foo (), 0)' without a warning. */
1797 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1799 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1803 case NON_LVALUE_EXPR:
1804 /* Don't warn about values cast to void. */
1805 if (TREE_TYPE (exp) == void_type_node)
1807 /* Don't warn about conversions not explicit in the user's program. */
1808 if (TREE_NO_UNUSED_WARNING (exp))
1810 /* Assignment to a cast usually results in a cast of a modify.
1811 Don't complain about that. There can be an arbitrary number of
1812 casts before the modify, so we must loop until we find the first
1813 non-cast expression and then test to see if that is a modify. */
1815 tree tem = TREE_OPERAND (exp, 0);
1817 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1818 tem = TREE_OPERAND (tem, 0);
1820 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
1821 || TREE_CODE (tem) == CALL_EXPR)
1827 /* Don't warn about automatic dereferencing of references, since
1828 the user cannot control it. */
1829 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
1830 return warn_if_unused_value (TREE_OPERAND (exp, 0));
1831 /* ... fall through ... */
1834 /* Referencing a volatile value is a side effect, so don't warn. */
1835 if ((TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
1836 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1837 && TREE_THIS_VOLATILE (exp))
1840 warning_with_file_and_line (emit_filename, emit_lineno,
1841 "value computed is not used");
1846 /* Clear out the memory of the last expression evaluated. */
1854 /* Begin a statement which will return a value.
1855 Return the RTL_EXPR for this statement expr.
1856 The caller must save that value and pass it to expand_end_stmt_expr. */
1859 expand_start_stmt_expr ()
1864 /* Make the RTL_EXPR node temporary, not momentary,
1865 so that rtl_expr_chain doesn't become garbage. */
1866 momentary = suspend_momentary ();
1867 t = make_node (RTL_EXPR);
1868 resume_momentary (momentary);
1869 do_pending_stack_adjust ();
1870 start_sequence_for_rtl_expr (t);
1872 expr_stmts_for_value++;
1876 /* Restore the previous state at the end of a statement that returns a value.
1877 Returns a tree node representing the statement's value and the
1878 insns to compute the value.
1880 The nodes of that expression have been freed by now, so we cannot use them.
1881 But we don't want to do that anyway; the expression has already been
1882 evaluated and now we just want to use the value. So generate a RTL_EXPR
1883 with the proper type and RTL value.
1885 If the last substatement was not an expression,
1886 return something with type `void'. */
1889 expand_end_stmt_expr (t)
1894 if (last_expr_type == 0)
1896 last_expr_type = void_type_node;
1897 last_expr_value = const0_rtx;
1899 else if (last_expr_value == 0)
1900 /* There are some cases where this can happen, such as when the
1901 statement is void type. */
1902 last_expr_value = const0_rtx;
1903 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
1904 /* Remove any possible QUEUED. */
1905 last_expr_value = protect_from_queue (last_expr_value, 0);
1909 TREE_TYPE (t) = last_expr_type;
1910 RTL_EXPR_RTL (t) = last_expr_value;
1911 RTL_EXPR_SEQUENCE (t) = get_insns ();
1913 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
1917 /* Don't consider deleting this expr or containing exprs at tree level. */
1918 TREE_SIDE_EFFECTS (t) = 1;
1919 /* Propagate volatility of the actual RTL expr. */
1920 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
1923 expr_stmts_for_value--;
1928 /* Generate RTL for the start of an if-then. COND is the expression
1929 whose truth should be tested.
1931 If EXITFLAG is nonzero, this conditional is visible to
1932 `exit_something'. */
1935 expand_start_cond (cond, exitflag)
1939 struct nesting *thiscond = ALLOC_NESTING ();
1941 /* Make an entry on cond_stack for the cond we are entering. */
1943 thiscond->next = cond_stack;
1944 thiscond->all = nesting_stack;
1945 thiscond->depth = ++nesting_depth;
1946 thiscond->data.cond.next_label = gen_label_rtx ();
1947 /* Before we encounter an `else', we don't need a separate exit label
1948 unless there are supposed to be exit statements
1949 to exit this conditional. */
1950 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
1951 thiscond->data.cond.endif_label = thiscond->exit_label;
1952 cond_stack = thiscond;
1953 nesting_stack = thiscond;
1955 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
1958 /* Generate RTL between then-clause and the elseif-clause
1959 of an if-then-elseif-.... */
1962 expand_start_elseif (cond)
1965 if (cond_stack->data.cond.endif_label == 0)
1966 cond_stack->data.cond.endif_label = gen_label_rtx ();
1967 emit_jump (cond_stack->data.cond.endif_label);
1968 emit_label (cond_stack->data.cond.next_label);
1969 cond_stack->data.cond.next_label = gen_label_rtx ();
1970 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1973 /* Generate RTL between the then-clause and the else-clause
1974 of an if-then-else. */
1977 expand_start_else ()
1979 if (cond_stack->data.cond.endif_label == 0)
1980 cond_stack->data.cond.endif_label = gen_label_rtx ();
1982 emit_jump (cond_stack->data.cond.endif_label);
1983 emit_label (cond_stack->data.cond.next_label);
1984 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
1987 /* After calling expand_start_else, turn this "else" into an "else if"
1988 by providing another condition. */
1991 expand_elseif (cond)
1994 cond_stack->data.cond.next_label = gen_label_rtx ();
1995 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1998 /* Generate RTL for the end of an if-then.
1999 Pop the record for it off of cond_stack. */
2004 struct nesting *thiscond = cond_stack;
2006 do_pending_stack_adjust ();
2007 if (thiscond->data.cond.next_label)
2008 emit_label (thiscond->data.cond.next_label);
2009 if (thiscond->data.cond.endif_label)
2010 emit_label (thiscond->data.cond.endif_label);
2012 POPSTACK (cond_stack);
2018 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2019 loop should be exited by `exit_something'. This is a loop for which
2020 `expand_continue' will jump to the top of the loop.
2022 Make an entry on loop_stack to record the labels associated with
2026 expand_start_loop (exit_flag)
2029 register struct nesting *thisloop = ALLOC_NESTING ();
2031 /* Make an entry on loop_stack for the loop we are entering. */
2033 thisloop->next = loop_stack;
2034 thisloop->all = nesting_stack;
2035 thisloop->depth = ++nesting_depth;
2036 thisloop->data.loop.start_label = gen_label_rtx ();
2037 thisloop->data.loop.end_label = gen_label_rtx ();
2038 thisloop->data.loop.alt_end_label = 0;
2039 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2040 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2041 loop_stack = thisloop;
2042 nesting_stack = thisloop;
2044 do_pending_stack_adjust ();
2046 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
2047 emit_label (thisloop->data.loop.start_label);
2052 /* Like expand_start_loop but for a loop where the continuation point
2053 (for expand_continue_loop) will be specified explicitly. */
2056 expand_start_loop_continue_elsewhere (exit_flag)
2059 struct nesting *thisloop = expand_start_loop (exit_flag);
2060 loop_stack->data.loop.continue_label = gen_label_rtx ();
2064 /* Specify the continuation point for a loop started with
2065 expand_start_loop_continue_elsewhere.
2066 Use this at the point in the code to which a continue statement
2070 expand_loop_continue_here ()
2072 do_pending_stack_adjust ();
2073 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
2074 emit_label (loop_stack->data.loop.continue_label);
2077 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2078 Pop the block off of loop_stack. */
2083 rtx start_label = loop_stack->data.loop.start_label;
2084 rtx insn = get_last_insn ();
2085 int needs_end_jump = 1;
2087 /* Mark the continue-point at the top of the loop if none elsewhere. */
2088 if (start_label == loop_stack->data.loop.continue_label)
2089 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2091 do_pending_stack_adjust ();
2093 /* If optimizing, perhaps reorder the loop.
2094 First, try to use a condjump near the end.
2095 expand_exit_loop_if_false ends loops with unconditional jumps,
2098 if (test) goto label;
2100 goto loop_stack->data.loop.end_label
2104 If we find such a pattern, we can end the loop earlier. */
2107 && GET_CODE (insn) == CODE_LABEL
2108 && LABEL_NAME (insn) == NULL
2109 && GET_CODE (PREV_INSN (insn)) == BARRIER)
2112 rtx jump = PREV_INSN (PREV_INSN (label));
2114 if (GET_CODE (jump) == JUMP_INSN
2115 && GET_CODE (PATTERN (jump)) == SET
2116 && SET_DEST (PATTERN (jump)) == pc_rtx
2117 && GET_CODE (SET_SRC (PATTERN (jump))) == LABEL_REF
2118 && (XEXP (SET_SRC (PATTERN (jump)), 0)
2119 == loop_stack->data.loop.end_label))
2123 /* The test might be complex and reference LABEL multiple times,
2124 like the loop in loop_iterations to set vtop. To handle this,
2126 insn = PREV_INSN (label);
2127 reorder_insns (label, label, start_label);
2129 for (prev = PREV_INSN (jump); ; prev = PREV_INSN (prev))
2131 /* We ignore line number notes, but if we see any other note,
2132 in particular NOTE_INSN_BLOCK_*, NOTE_INSN_EH_REGION_*,
2133 NOTE_INSN_LOOP_*, we disable this optimization. */
2134 if (GET_CODE (prev) == NOTE)
2136 if (NOTE_LINE_NUMBER (prev) < 0)
2140 if (GET_CODE (prev) == CODE_LABEL)
2142 if (GET_CODE (prev) == JUMP_INSN)
2144 if (GET_CODE (PATTERN (prev)) == SET
2145 && SET_DEST (PATTERN (prev)) == pc_rtx
2146 && GET_CODE (SET_SRC (PATTERN (prev))) == IF_THEN_ELSE
2147 && (GET_CODE (XEXP (SET_SRC (PATTERN (prev)), 1))
2149 && XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0) == label)
2151 XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0)
2153 emit_note_after (NOTE_INSN_LOOP_END, prev);
2162 /* If the loop starts with a loop exit, roll that to the end where
2163 it will optimize together with the jump back.
2165 We look for the conditional branch to the exit, except that once
2166 we find such a branch, we don't look past 30 instructions.
2168 In more detail, if the loop presently looks like this (in pseudo-C):
2171 if (test) goto end_label;
2176 transform it to look like:
2182 if (test) goto end_label;
2183 goto newstart_label;
2186 Here, the `test' may actually consist of some reasonably complex
2187 code, terminating in a test. */
2192 ! (GET_CODE (insn) == JUMP_INSN
2193 && GET_CODE (PATTERN (insn)) == SET
2194 && SET_DEST (PATTERN (insn)) == pc_rtx
2195 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
2199 rtx last_test_insn = NULL_RTX;
2201 /* Scan insns from the top of the loop looking for a qualified
2202 conditional exit. */
2203 for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
2204 insn = NEXT_INSN (insn))
2206 if (GET_CODE (insn) == NOTE)
2209 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2210 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2211 /* The code that actually moves the exit test will
2212 carefully leave BLOCK notes in their original
2213 location. That means, however, that we can't debug
2214 the exit test itself. So, we refuse to move code
2215 containing BLOCK notes at low optimization levels. */
2218 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
2220 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
2224 /* We've come to the end of an EH region, but
2225 never saw the beginning of that region. That
2226 means that an EH region begins before the top
2227 of the loop, and ends in the middle of it. The
2228 existence of such a situation violates a basic
2229 assumption in this code, since that would imply
2230 that even when EH_REGIONS is zero, we might
2231 move code out of an exception region. */
2235 /* We must not walk into a nested loop. */
2236 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
2239 /* We already know this INSN is a NOTE, so there's no
2240 point in looking at it to see if it's a JUMP. */
2244 if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2247 if (last_test_insn && num_insns > 30)
2251 /* We don't want to move a partial EH region. Consider:
2265 This isn't legal C++, but here's what it's supposed to
2266 mean: if cond() is true, stop looping. Otherwise,
2267 call bar, and keep looping. In addition, if cond
2268 throws an exception, catch it and keep looping. Such
2269 constructs are certainy legal in LISP.
2271 We should not move the `if (cond()) 0' test since then
2272 the EH-region for the try-block would be broken up.
2273 (In this case we would the EH_BEG note for the `try'
2274 and `if cond()' but not the call to bar() or the
2277 So we don't look for tests within an EH region. */
2280 if (GET_CODE (insn) == JUMP_INSN
2281 && GET_CODE (PATTERN (insn)) == SET
2282 && SET_DEST (PATTERN (insn)) == pc_rtx)
2284 /* This is indeed a jump. */
2285 rtx dest1 = NULL_RTX;
2286 rtx dest2 = NULL_RTX;
2287 rtx potential_last_test;
2288 if (GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE)
2290 /* A conditional jump. */
2291 dest1 = XEXP (SET_SRC (PATTERN (insn)), 1);
2292 dest2 = XEXP (SET_SRC (PATTERN (insn)), 2);
2293 potential_last_test = insn;
2297 /* An unconditional jump. */
2298 dest1 = SET_SRC (PATTERN (insn));
2299 /* Include the BARRIER after the JUMP. */
2300 potential_last_test = NEXT_INSN (insn);
2304 if (dest1 && GET_CODE (dest1) == LABEL_REF
2305 && ((XEXP (dest1, 0)
2306 == loop_stack->data.loop.alt_end_label)
2308 == loop_stack->data.loop.end_label)))
2310 last_test_insn = potential_last_test;
2314 /* If this was a conditional jump, there may be
2315 another label at which we should look. */
2322 if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2324 /* We found one. Move everything from there up
2325 to the end of the loop, and add a jump into the loop
2326 to jump to there. */
2327 register rtx newstart_label = gen_label_rtx ();
2328 register rtx start_move = start_label;
2331 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2332 then we want to move this note also. */
2333 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2334 && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2335 == NOTE_INSN_LOOP_CONT))
2336 start_move = PREV_INSN (start_move);
2338 emit_label_after (newstart_label, PREV_INSN (start_move));
2340 /* Actually move the insns. Start at the beginning, and
2341 keep copying insns until we've copied the
2343 for (insn = start_move; insn; insn = next_insn)
2345 /* Figure out which insn comes after this one. We have
2346 to do this before we move INSN. */
2347 if (insn == last_test_insn)
2348 /* We've moved all the insns. */
2349 next_insn = NULL_RTX;
2351 next_insn = NEXT_INSN (insn);
2353 if (GET_CODE (insn) == NOTE
2354 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2355 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2356 /* We don't want to move NOTE_INSN_BLOCK_BEGs or
2357 NOTE_INSN_BLOCK_ENDs because the correct generation
2358 of debugging information depends on these appearing
2359 in the same order in the RTL and in the tree
2360 structure, where they are represented as BLOCKs.
2361 So, we don't move block notes. Of course, moving
2362 the code inside the block is likely to make it
2363 impossible to debug the instructions in the exit
2364 test, but such is the price of optimization. */
2367 /* Move the INSN. */
2368 reorder_insns (insn, insn, get_last_insn ());
2371 emit_jump_insn_after (gen_jump (start_label),
2372 PREV_INSN (newstart_label));
2373 emit_barrier_after (PREV_INSN (newstart_label));
2374 start_label = newstart_label;
2380 emit_jump (start_label);
2381 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
2383 emit_label (loop_stack->data.loop.end_label);
2385 POPSTACK (loop_stack);
2390 /* Generate a jump to the current loop's continue-point.
2391 This is usually the top of the loop, but may be specified
2392 explicitly elsewhere. If not currently inside a loop,
2393 return 0 and do nothing; caller will print an error message. */
2396 expand_continue_loop (whichloop)
2397 struct nesting *whichloop;
2401 whichloop = loop_stack;
2404 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2409 /* Generate a jump to exit the current loop. If not currently inside a loop,
2410 return 0 and do nothing; caller will print an error message. */
2413 expand_exit_loop (whichloop)
2414 struct nesting *whichloop;
2418 whichloop = loop_stack;
2421 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2425 /* Generate a conditional jump to exit the current loop if COND
2426 evaluates to zero. If not currently inside a loop,
2427 return 0 and do nothing; caller will print an error message. */
2430 expand_exit_loop_if_false (whichloop, cond)
2431 struct nesting *whichloop;
2434 rtx label = gen_label_rtx ();
2439 whichloop = loop_stack;
2442 /* In order to handle fixups, we actually create a conditional jump
2443 around a unconditional branch to exit the loop. If fixups are
2444 necessary, they go before the unconditional branch. */
2447 do_jump (cond, NULL_RTX, label);
2448 last_insn = get_last_insn ();
2449 if (GET_CODE (last_insn) == CODE_LABEL)
2450 whichloop->data.loop.alt_end_label = last_insn;
2451 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2458 /* Return nonzero if the loop nest is empty. Else return zero. */
2461 stmt_loop_nest_empty ()
2463 return (loop_stack == NULL);
2466 /* Return non-zero if we should preserve sub-expressions as separate
2467 pseudos. We never do so if we aren't optimizing. We always do so
2468 if -fexpensive-optimizations.
2470 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2471 the loop may still be a small one. */
2474 preserve_subexpressions_p ()
2478 if (flag_expensive_optimizations)
2481 if (optimize == 0 || loop_stack == 0)
2484 insn = get_last_insn_anywhere ();
2487 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2488 < n_non_fixed_regs * 3));
2492 /* Generate a jump to exit the current loop, conditional, binding contour
2493 or case statement. Not all such constructs are visible to this function,
2494 only those started with EXIT_FLAG nonzero. Individual languages use
2495 the EXIT_FLAG parameter to control which kinds of constructs you can
2498 If not currently inside anything that can be exited,
2499 return 0 and do nothing; caller will print an error message. */
2502 expand_exit_something ()
2506 for (n = nesting_stack; n; n = n->all)
2507 if (n->exit_label != 0)
2509 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2516 /* Generate RTL to return from the current function, with no value.
2517 (That is, we do not do anything about returning any value.) */
2520 expand_null_return ()
2522 struct nesting *block = block_stack;
2525 /* Does any pending block have cleanups? */
2527 while (block && block->data.block.cleanups == 0)
2528 block = block->next;
2530 /* If yes, use a goto to return, since that runs cleanups. */
2532 expand_null_return_1 (last_insn, block != 0);
2535 /* Generate RTL to return from the current function, with value VAL. */
2538 expand_value_return (val)
2541 struct nesting *block = block_stack;
2542 rtx last_insn = get_last_insn ();
2543 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2545 /* Copy the value to the return location
2546 unless it's already there. */
2548 if (return_reg != val)
2550 #ifdef PROMOTE_FUNCTION_RETURN
2551 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2552 int unsignedp = TREE_UNSIGNED (type);
2553 enum machine_mode mode
2554 = promote_mode (type, DECL_MODE (DECL_RESULT (current_function_decl)),
2557 if (GET_MODE (val) != VOIDmode && GET_MODE (val) != mode)
2558 convert_move (return_reg, val, unsignedp);
2561 emit_move_insn (return_reg, val);
2563 if (GET_CODE (return_reg) == REG
2564 && REGNO (return_reg) < FIRST_PSEUDO_REGISTER)
2565 emit_insn (gen_rtx_USE (VOIDmode, return_reg));
2566 /* Handle calls that return values in multiple non-contiguous locations.
2567 The Irix 6 ABI has examples of this. */
2568 else if (GET_CODE (return_reg) == PARALLEL)
2572 for (i = 0; i < XVECLEN (return_reg, 0); i++)
2574 rtx x = XEXP (XVECEXP (return_reg, 0, i), 0);
2576 if (GET_CODE (x) == REG
2577 && REGNO (x) < FIRST_PSEUDO_REGISTER)
2578 emit_insn (gen_rtx_USE (VOIDmode, x));
2582 /* Does any pending block have cleanups? */
2584 while (block && block->data.block.cleanups == 0)
2585 block = block->next;
2587 /* If yes, use a goto to return, since that runs cleanups.
2588 Use LAST_INSN to put cleanups *before* the move insn emitted above. */
2590 expand_null_return_1 (last_insn, block != 0);
2593 /* Output a return with no value. If LAST_INSN is nonzero,
2594 pretend that the return takes place after LAST_INSN.
2595 If USE_GOTO is nonzero then don't use a return instruction;
2596 go to the return label instead. This causes any cleanups
2597 of pending blocks to be executed normally. */
2600 expand_null_return_1 (last_insn, use_goto)
2604 rtx end_label = cleanup_label ? cleanup_label : return_label;
2606 clear_pending_stack_adjust ();
2607 do_pending_stack_adjust ();
2610 /* PCC-struct return always uses an epilogue. */
2611 if (current_function_returns_pcc_struct || use_goto)
2614 end_label = return_label = gen_label_rtx ();
2615 expand_goto_internal (NULL_TREE, end_label, last_insn);
2619 /* Otherwise output a simple return-insn if one is available,
2620 unless it won't do the job. */
2622 if (HAVE_return && use_goto == 0 && cleanup_label == 0)
2624 emit_jump_insn (gen_return ());
2630 /* Otherwise jump to the epilogue. */
2631 expand_goto_internal (NULL_TREE, end_label, last_insn);
2634 /* Generate RTL to evaluate the expression RETVAL and return it
2635 from the current function. */
2638 expand_return (retval)
2641 /* If there are any cleanups to be performed, then they will
2642 be inserted following LAST_INSN. It is desirable
2643 that the last_insn, for such purposes, should be the
2644 last insn before computing the return value. Otherwise, cleanups
2645 which call functions can clobber the return value. */
2646 /* ??? rms: I think that is erroneous, because in C++ it would
2647 run destructors on variables that might be used in the subsequent
2648 computation of the return value. */
2650 register rtx val = 0;
2655 /* If function wants no value, give it none. */
2656 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2658 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2660 expand_null_return ();
2664 /* Are any cleanups needed? E.g. C++ destructors to be run? */
2665 /* This is not sufficient. We also need to watch for cleanups of the
2666 expression we are about to expand. Unfortunately, we cannot know
2667 if it has cleanups until we expand it, and we want to change how we
2668 expand it depending upon if we need cleanups. We can't win. */
2670 cleanups = any_pending_cleanups (1);
2675 if (TREE_CODE (retval) == RESULT_DECL)
2676 retval_rhs = retval;
2677 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2678 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2679 retval_rhs = TREE_OPERAND (retval, 1);
2680 else if (TREE_TYPE (retval) == void_type_node)
2681 /* Recognize tail-recursive call to void function. */
2682 retval_rhs = retval;
2684 retval_rhs = NULL_TREE;
2686 /* Only use `last_insn' if there are cleanups which must be run. */
2687 if (cleanups || cleanup_label != 0)
2688 last_insn = get_last_insn ();
2690 /* Distribute return down conditional expr if either of the sides
2691 may involve tail recursion (see test below). This enhances the number
2692 of tail recursions we see. Don't do this always since it can produce
2693 sub-optimal code in some cases and we distribute assignments into
2694 conditional expressions when it would help. */
2696 if (optimize && retval_rhs != 0
2697 && frame_offset == 0
2698 && TREE_CODE (retval_rhs) == COND_EXPR
2699 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
2700 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
2702 rtx label = gen_label_rtx ();
2705 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
2706 start_cleanup_deferral ();
2707 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
2708 DECL_RESULT (current_function_decl),
2709 TREE_OPERAND (retval_rhs, 1));
2710 TREE_SIDE_EFFECTS (expr) = 1;
2711 expand_return (expr);
2714 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
2715 DECL_RESULT (current_function_decl),
2716 TREE_OPERAND (retval_rhs, 2));
2717 TREE_SIDE_EFFECTS (expr) = 1;
2718 expand_return (expr);
2719 end_cleanup_deferral ();
2723 /* Attempt to optimize the call if it is tail recursive. */
2724 if (optimize_tail_recursion (retval_rhs, last_insn))
2728 /* This optimization is safe if there are local cleanups
2729 because expand_null_return takes care of them.
2730 ??? I think it should also be safe when there is a cleanup label,
2731 because expand_null_return takes care of them, too.
2732 Any reason why not? */
2733 if (HAVE_return && cleanup_label == 0
2734 && ! current_function_returns_pcc_struct
2735 && BRANCH_COST <= 1)
2737 /* If this is return x == y; then generate
2738 if (x == y) return 1; else return 0;
2739 if we can do it with explicit return insns and branches are cheap,
2740 but not if we have the corresponding scc insn. */
2743 switch (TREE_CODE (retval_rhs))
2769 case TRUTH_ANDIF_EXPR:
2770 case TRUTH_ORIF_EXPR:
2771 case TRUTH_AND_EXPR:
2773 case TRUTH_NOT_EXPR:
2774 case TRUTH_XOR_EXPR:
2777 op0 = gen_label_rtx ();
2778 jumpifnot (retval_rhs, op0);
2779 expand_value_return (const1_rtx);
2781 expand_value_return (const0_rtx);
2790 #endif /* HAVE_return */
2792 /* If the result is an aggregate that is being returned in one (or more)
2793 registers, load the registers here. The compiler currently can't handle
2794 copying a BLKmode value into registers. We could put this code in a
2795 more general area (for use by everyone instead of just function
2796 call/return), but until this feature is generally usable it is kept here
2797 (and in expand_call). The value must go into a pseudo in case there
2798 are cleanups that will clobber the real return register. */
2801 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
2802 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2804 int i, bitpos, xbitpos;
2805 int big_endian_correction = 0;
2806 int bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2807 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2808 int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)),
2809 (unsigned int)BITS_PER_WORD);
2810 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
2811 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
2812 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2813 enum machine_mode tmpmode, result_reg_mode;
2815 /* Structures whose size is not a multiple of a word are aligned
2816 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
2817 machine, this means we must skip the empty high order bytes when
2818 calculating the bit offset. */
2819 if (BYTES_BIG_ENDIAN && bytes % UNITS_PER_WORD)
2820 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
2823 /* Copy the structure BITSIZE bits at a time. */
2824 for (bitpos = 0, xbitpos = big_endian_correction;
2825 bitpos < bytes * BITS_PER_UNIT;
2826 bitpos += bitsize, xbitpos += bitsize)
2828 /* We need a new destination pseudo each time xbitpos is
2829 on a word boundary and when xbitpos == big_endian_correction
2830 (the first time through). */
2831 if (xbitpos % BITS_PER_WORD == 0
2832 || xbitpos == big_endian_correction)
2834 /* Generate an appropriate register. */
2835 dst = gen_reg_rtx (word_mode);
2836 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
2838 /* Clobber the destination before we move anything into it. */
2839 emit_insn (gen_rtx_CLOBBER (VOIDmode, dst));
2842 /* We need a new source operand each time bitpos is on a word
2844 if (bitpos % BITS_PER_WORD == 0)
2845 src = operand_subword_force (result_val,
2846 bitpos / BITS_PER_WORD,
2849 /* Use bitpos for the source extraction (left justified) and
2850 xbitpos for the destination store (right justified). */
2851 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
2852 extract_bit_field (src, bitsize,
2853 bitpos % BITS_PER_WORD, 1,
2854 NULL_RTX, word_mode,
2856 bitsize / BITS_PER_UNIT,
2858 bitsize / BITS_PER_UNIT, BITS_PER_WORD);
2861 /* Find the smallest integer mode large enough to hold the
2862 entire structure and use that mode instead of BLKmode
2863 on the USE insn for the return register. */
2864 bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2865 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
2866 tmpmode != MAX_MACHINE_MODE;
2867 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
2869 /* Have we found a large enough mode? */
2870 if (GET_MODE_SIZE (tmpmode) >= bytes)
2874 /* No suitable mode found. */
2875 if (tmpmode == MAX_MACHINE_MODE)
2878 PUT_MODE (DECL_RTL (DECL_RESULT (current_function_decl)), tmpmode);
2880 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
2881 result_reg_mode = word_mode;
2883 result_reg_mode = tmpmode;
2884 result_reg = gen_reg_rtx (result_reg_mode);
2887 for (i = 0; i < n_regs; i++)
2888 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
2891 if (tmpmode != result_reg_mode)
2892 result_reg = gen_lowpart (tmpmode, result_reg);
2894 expand_value_return (result_reg);
2898 && TREE_TYPE (retval_rhs) != void_type_node
2899 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2901 /* Calculate the return value into a pseudo reg. */
2902 val = gen_reg_rtx (DECL_MODE (DECL_RESULT (current_function_decl)));
2903 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
2904 val = force_not_mem (val);
2906 /* Return the calculated value, doing cleanups first. */
2907 expand_value_return (val);
2911 /* No cleanups or no hard reg used;
2912 calculate value into hard return reg. */
2913 expand_expr (retval, const0_rtx, VOIDmode, 0);
2915 expand_value_return (DECL_RTL (DECL_RESULT (current_function_decl)));
2919 /* Return 1 if the end of the generated RTX is not a barrier.
2920 This means code already compiled can drop through. */
2923 drop_through_at_end_p ()
2925 rtx insn = get_last_insn ();
2926 while (insn && GET_CODE (insn) == NOTE)
2927 insn = PREV_INSN (insn);
2928 return insn && GET_CODE (insn) != BARRIER;
2931 /* Test CALL_EXPR to determine if it is a potential tail recursion call
2932 and emit code to optimize the tail recursion. LAST_INSN indicates where
2933 to place the jump to the tail recursion label. Return TRUE if the
2934 call was optimized into a goto.
2936 This is only used by expand_return, but expand_call is expected to
2940 optimize_tail_recursion (call_expr, last_insn)
2944 /* For tail-recursive call to current function,
2945 just jump back to the beginning.
2946 It's unsafe if any auto variable in this function
2947 has its address taken; for simplicity,
2948 require stack frame to be empty. */
2949 if (optimize && call_expr != 0
2950 && frame_offset == 0
2951 && TREE_CODE (call_expr) == CALL_EXPR
2952 && TREE_CODE (TREE_OPERAND (call_expr, 0)) == ADDR_EXPR
2953 && TREE_OPERAND (TREE_OPERAND (call_expr, 0), 0) == current_function_decl
2954 /* Finish checking validity, and if valid emit code
2955 to set the argument variables for the new call. */
2956 && tail_recursion_args (TREE_OPERAND (call_expr, 1),
2957 DECL_ARGUMENTS (current_function_decl)))
2959 if (tail_recursion_label == 0)
2961 tail_recursion_label = gen_label_rtx ();
2962 emit_label_after (tail_recursion_label,
2963 tail_recursion_reentry);
2966 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
2974 /* Emit code to alter this function's formal parms for a tail-recursive call.
2975 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
2976 FORMALS is the chain of decls of formals.
2977 Return 1 if this can be done;
2978 otherwise return 0 and do not emit any code. */
2981 tail_recursion_args (actuals, formals)
2982 tree actuals, formals;
2984 register tree a = actuals, f = formals;
2986 register rtx *argvec;
2988 /* Check that number and types of actuals are compatible
2989 with the formals. This is not always true in valid C code.
2990 Also check that no formal needs to be addressable
2991 and that all formals are scalars. */
2993 /* Also count the args. */
2995 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
2997 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
2998 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3000 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3003 if (a != 0 || f != 0)
3006 /* Compute all the actuals. */
3008 argvec = (rtx *) alloca (i * sizeof (rtx));
3010 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3011 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3013 /* Find which actual values refer to current values of previous formals.
3014 Copy each of them now, before any formal is changed. */
3016 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3020 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3021 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3022 { copy = 1; break; }
3024 argvec[i] = copy_to_reg (argvec[i]);
3027 /* Store the values of the actuals into the formals. */
3029 for (f = formals, a = actuals, i = 0; f;
3030 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3032 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3033 emit_move_insn (DECL_RTL (f), argvec[i]);
3035 convert_move (DECL_RTL (f), argvec[i],
3036 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3043 /* Generate the RTL code for entering a binding contour.
3044 The variables are declared one by one, by calls to `expand_decl'.
3046 EXIT_FLAG is nonzero if this construct should be visible to
3047 `exit_something'. */
3050 expand_start_bindings (exit_flag)
3053 struct nesting *thisblock = ALLOC_NESTING ();
3054 rtx note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
3056 /* Make an entry on block_stack for the block we are entering. */
3058 thisblock->next = block_stack;
3059 thisblock->all = nesting_stack;
3060 thisblock->depth = ++nesting_depth;
3061 thisblock->data.block.stack_level = 0;
3062 thisblock->data.block.cleanups = 0;
3063 thisblock->data.block.function_call_count = 0;
3064 thisblock->data.block.exception_region = 0;
3065 thisblock->data.block.target_temp_slot_level = target_temp_slot_level;
3067 thisblock->data.block.conditional_code = 0;
3068 thisblock->data.block.last_unconditional_cleanup = note;
3069 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
3072 && !(block_stack->data.block.cleanups == NULL_TREE
3073 && block_stack->data.block.outer_cleanups == NULL_TREE))
3074 thisblock->data.block.outer_cleanups
3075 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3076 block_stack->data.block.outer_cleanups);
3078 thisblock->data.block.outer_cleanups = 0;
3079 thisblock->data.block.label_chain = 0;
3080 thisblock->data.block.innermost_stack_block = stack_block_stack;
3081 thisblock->data.block.first_insn = note;
3082 thisblock->data.block.block_start_count = ++block_start_count;
3083 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3084 block_stack = thisblock;
3085 nesting_stack = thisblock;
3087 /* Make a new level for allocating stack slots. */
3091 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3092 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3093 expand_expr are made. After we end the region, we know that all
3094 space for all temporaries that were created by TARGET_EXPRs will be
3095 destroyed and their space freed for reuse. */
3098 expand_start_target_temps ()
3100 /* This is so that even if the result is preserved, the space
3101 allocated will be freed, as we know that it is no longer in use. */
3104 /* Start a new binding layer that will keep track of all cleanup
3105 actions to be performed. */
3106 expand_start_bindings (0);
3108 target_temp_slot_level = temp_slot_level;
3112 expand_end_target_temps ()
3114 expand_end_bindings (NULL_TREE, 0, 0);
3116 /* This is so that even if the result is preserved, the space
3117 allocated will be freed, as we know that it is no longer in use. */
3121 /* Mark top block of block_stack as an implicit binding for an
3122 exception region. This is used to prevent infinite recursion when
3123 ending a binding with expand_end_bindings. It is only ever called
3124 by expand_eh_region_start, as that it the only way to create a
3125 block stack for a exception region. */
3128 mark_block_as_eh_region ()
3130 block_stack->data.block.exception_region = 1;
3131 if (block_stack->next
3132 && block_stack->next->data.block.conditional_code)
3134 block_stack->data.block.conditional_code
3135 = block_stack->next->data.block.conditional_code;
3136 block_stack->data.block.last_unconditional_cleanup
3137 = block_stack->next->data.block.last_unconditional_cleanup;
3138 block_stack->data.block.cleanup_ptr
3139 = block_stack->next->data.block.cleanup_ptr;
3143 /* True if we are currently emitting insns in an area of output code
3144 that is controlled by a conditional expression. This is used by
3145 the cleanup handling code to generate conditional cleanup actions. */
3148 conditional_context ()
3150 return block_stack && block_stack->data.block.conditional_code;
3153 /* Mark top block of block_stack as not for an implicit binding for an
3154 exception region. This is only ever done by expand_eh_region_end
3155 to let expand_end_bindings know that it is being called explicitly
3156 to end the binding layer for just the binding layer associated with
3157 the exception region, otherwise expand_end_bindings would try and
3158 end all implicit binding layers for exceptions regions, and then
3159 one normal binding layer. */
3162 mark_block_as_not_eh_region ()
3164 block_stack->data.block.exception_region = 0;
3167 /* True if the top block of block_stack was marked as for an exception
3168 region by mark_block_as_eh_region. */
3173 return block_stack && block_stack->data.block.exception_region;
3176 /* Given a pointer to a BLOCK node, save a pointer to the most recently
3177 generated NOTE_INSN_BLOCK_END in the BLOCK_END_NOTE field of the given
3181 remember_end_note (block)
3182 register tree block;
3184 BLOCK_END_NOTE (block) = last_block_end_note;
3185 last_block_end_note = NULL_RTX;
3188 /* Emit a handler label for a nonlocal goto handler.
3189 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3192 expand_nl_handler_label (slot, before_insn)
3193 rtx slot, before_insn;
3196 rtx handler_label = gen_label_rtx ();
3198 /* Don't let jump_optimize delete the handler. */
3199 LABEL_PRESERVE_P (handler_label) = 1;
3202 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3203 insns = get_insns ();
3205 emit_insns_before (insns, before_insn);
3207 emit_label (handler_label);
3209 return handler_label;
3212 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3215 expand_nl_goto_receiver ()
3217 #ifdef HAVE_nonlocal_goto
3218 if (! HAVE_nonlocal_goto)
3220 /* First adjust our frame pointer to its actual value. It was
3221 previously set to the start of the virtual area corresponding to
3222 the stacked variables when we branched here and now needs to be
3223 adjusted to the actual hardware fp value.
3225 Assignments are to virtual registers are converted by
3226 instantiate_virtual_regs into the corresponding assignment
3227 to the underlying register (fp in this case) that makes
3228 the original assignment true.
3229 So the following insn will actually be
3230 decrementing fp by STARTING_FRAME_OFFSET. */
3231 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3233 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3234 if (fixed_regs[ARG_POINTER_REGNUM])
3236 #ifdef ELIMINABLE_REGS
3237 /* If the argument pointer can be eliminated in favor of the
3238 frame pointer, we don't need to restore it. We assume here
3239 that if such an elimination is present, it can always be used.
3240 This is the case on all known machines; if we don't make this
3241 assumption, we do unnecessary saving on many machines. */
3242 static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
3245 for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
3246 if (elim_regs[i].from == ARG_POINTER_REGNUM
3247 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3250 if (i == sizeof elim_regs / sizeof elim_regs [0])
3253 /* Now restore our arg pointer from the address at which it
3254 was saved in our stack frame.
3255 If there hasn't be space allocated for it yet, make
3257 if (arg_pointer_save_area == 0)
3258 arg_pointer_save_area
3259 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
3260 emit_move_insn (virtual_incoming_args_rtx,
3261 /* We need a pseudo here, or else
3262 instantiate_virtual_regs_1 complains. */
3263 copy_to_reg (arg_pointer_save_area));
3268 #ifdef HAVE_nonlocal_goto_receiver
3269 if (HAVE_nonlocal_goto_receiver)
3270 emit_insn (gen_nonlocal_goto_receiver ());
3274 /* Make handlers for nonlocal gotos taking place in the function calls in
3278 expand_nl_goto_receivers (thisblock)
3279 struct nesting *thisblock;
3282 rtx afterward = gen_label_rtx ();
3287 /* Record the handler address in the stack slot for that purpose,
3288 during this block, saving and restoring the outer value. */
3289 if (thisblock->next != 0)
3290 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3292 rtx save_receiver = gen_reg_rtx (Pmode);
3293 emit_move_insn (XEXP (slot, 0), save_receiver);
3296 emit_move_insn (save_receiver, XEXP (slot, 0));
3297 insns = get_insns ();
3299 emit_insns_before (insns, thisblock->data.block.first_insn);
3302 /* Jump around the handlers; they run only when specially invoked. */
3303 emit_jump (afterward);
3305 /* Make a separate handler for each label. */
3306 link = nonlocal_labels;
3307 slot = nonlocal_goto_handler_slots;
3308 label_list = NULL_RTX;
3309 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3310 /* Skip any labels we shouldn't be able to jump to from here,
3311 we generate one special handler for all of them below which just calls
3313 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3316 lab = expand_nl_handler_label (XEXP (slot, 0),
3317 thisblock->data.block.first_insn);
3318 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3320 expand_nl_goto_receiver ();
3322 /* Jump to the "real" nonlocal label. */
3323 expand_goto (TREE_VALUE (link));
3326 /* A second pass over all nonlocal labels; this time we handle those
3327 we should not be able to jump to at this point. */
3328 link = nonlocal_labels;
3329 slot = nonlocal_goto_handler_slots;
3331 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3332 if (DECL_TOO_LATE (TREE_VALUE (link)))
3335 lab = expand_nl_handler_label (XEXP (slot, 0),
3336 thisblock->data.block.first_insn);
3337 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3343 expand_nl_goto_receiver ();
3344 emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "abort"), 0,
3349 nonlocal_goto_handler_labels = label_list;
3350 emit_label (afterward);
3353 /* Generate RTL code to terminate a binding contour.
3354 VARS is the chain of VAR_DECL nodes
3355 for the variables bound in this contour.
3356 MARK_ENDS is nonzero if we should put a note at the beginning
3357 and end of this binding contour.
3359 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3360 (That is true automatically if the contour has a saved stack level.) */
3363 expand_end_bindings (vars, mark_ends, dont_jump_in)
3368 register struct nesting *thisblock;
3371 while (block_stack->data.block.exception_region)
3373 /* Because we don't need or want a new temporary level and
3374 because we didn't create one in expand_eh_region_start,
3375 create a fake one now to avoid removing one in
3376 expand_end_bindings. */
3379 block_stack->data.block.exception_region = 0;
3381 expand_end_bindings (NULL_TREE, 0, 0);
3384 /* Since expand_eh_region_start does an expand_start_bindings, we
3385 have to first end all the bindings that were created by
3386 expand_eh_region_start. */
3388 thisblock = block_stack;
3391 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3392 if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL
3393 && ! DECL_IN_SYSTEM_HEADER (decl)
3394 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3395 warning_with_decl (decl, "unused variable `%s'");
3397 if (thisblock->exit_label)
3399 do_pending_stack_adjust ();
3400 emit_label (thisblock->exit_label);
3403 /* If necessary, make handlers for nonlocal gotos taking
3404 place in the function calls in this block. */
3405 if (function_call_count != thisblock->data.block.function_call_count
3407 /* Make handler for outermost block
3408 if there were any nonlocal gotos to this function. */
3409 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3410 /* Make handler for inner block if it has something
3411 special to do when you jump out of it. */
3412 : (thisblock->data.block.cleanups != 0
3413 || thisblock->data.block.stack_level != 0)))
3414 expand_nl_goto_receivers (thisblock);
3416 /* Don't allow jumping into a block that has a stack level.
3417 Cleanups are allowed, though. */
3419 || thisblock->data.block.stack_level != 0)
3421 struct label_chain *chain;
3423 /* Any labels in this block are no longer valid to go to.
3424 Mark them to cause an error message. */
3425 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3427 DECL_TOO_LATE (chain->label) = 1;
3428 /* If any goto without a fixup came to this label,
3429 that must be an error, because gotos without fixups
3430 come from outside all saved stack-levels. */
3431 if (TREE_ADDRESSABLE (chain->label))
3432 error_with_decl (chain->label,
3433 "label `%s' used before containing binding contour");
3437 /* Restore stack level in effect before the block
3438 (only if variable-size objects allocated). */
3439 /* Perform any cleanups associated with the block. */
3441 if (thisblock->data.block.stack_level != 0
3442 || thisblock->data.block.cleanups != 0)
3444 /* Only clean up here if this point can actually be reached. */
3445 int reachable = GET_CODE (get_last_insn ()) != BARRIER;
3447 /* Don't let cleanups affect ({...}) constructs. */
3448 int old_expr_stmts_for_value = expr_stmts_for_value;
3449 rtx old_last_expr_value = last_expr_value;
3450 tree old_last_expr_type = last_expr_type;
3451 expr_stmts_for_value = 0;
3453 /* Do the cleanups. */
3454 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3456 do_pending_stack_adjust ();
3458 expr_stmts_for_value = old_expr_stmts_for_value;
3459 last_expr_value = old_last_expr_value;
3460 last_expr_type = old_last_expr_type;
3462 /* Restore the stack level. */
3464 if (reachable && thisblock->data.block.stack_level != 0)
3466 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3467 thisblock->data.block.stack_level, NULL_RTX);
3468 if (nonlocal_goto_handler_slots != 0)
3469 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3473 /* Any gotos out of this block must also do these things.
3474 Also report any gotos with fixups that came to labels in this
3476 fixup_gotos (thisblock,
3477 thisblock->data.block.stack_level,
3478 thisblock->data.block.cleanups,
3479 thisblock->data.block.first_insn,
3483 /* Mark the beginning and end of the scope if requested.
3484 We do this now, after running cleanups on the variables
3485 just going out of scope, so they are in scope for their cleanups. */
3488 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
3490 /* Get rid of the beginning-mark if we don't make an end-mark. */
3491 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3493 /* If doing stupid register allocation, make sure lives of all
3494 register variables declared here extend thru end of scope. */
3497 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3499 rtx rtl = DECL_RTL (decl);
3500 if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
3504 /* Restore the temporary level of TARGET_EXPRs. */
3505 target_temp_slot_level = thisblock->data.block.target_temp_slot_level;
3507 /* Restore block_stack level for containing block. */
3509 stack_block_stack = thisblock->data.block.innermost_stack_block;
3510 POPSTACK (block_stack);
3512 /* Pop the stack slot nesting and free any slots at this level. */
3516 /* Generate RTL for the automatic variable declaration DECL.
3517 (Other kinds of declarations are simply ignored if seen here.) */
3523 struct nesting *thisblock = block_stack;
3526 type = TREE_TYPE (decl);
3528 /* Only automatic variables need any expansion done.
3529 Static and external variables, and external functions,
3530 will be handled by `assemble_variable' (called from finish_decl).
3531 TYPE_DECL and CONST_DECL require nothing.
3532 PARM_DECLs are handled in `assign_parms'. */
3534 if (TREE_CODE (decl) != VAR_DECL)
3536 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3539 /* Create the RTL representation for the variable. */
3541 if (type == error_mark_node)
3542 DECL_RTL (decl) = gen_rtx_MEM (BLKmode, const0_rtx);
3543 else if (DECL_SIZE (decl) == 0)
3544 /* Variable with incomplete type. */
3546 if (DECL_INITIAL (decl) == 0)
3547 /* Error message was already done; now avoid a crash. */
3548 DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
3550 /* An initializer is going to decide the size of this array.
3551 Until we know the size, represent its address with a reg. */
3552 DECL_RTL (decl) = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3553 MEM_SET_IN_STRUCT_P (DECL_RTL (decl), AGGREGATE_TYPE_P (type));
3555 else if (DECL_MODE (decl) != BLKmode
3556 /* If -ffloat-store, don't put explicit float vars
3558 && !(flag_float_store
3559 && TREE_CODE (type) == REAL_TYPE)
3560 && ! TREE_THIS_VOLATILE (decl)
3561 && ! TREE_ADDRESSABLE (decl)
3562 && (DECL_REGISTER (decl) || ! obey_regdecls)
3563 /* if -fcheck-memory-usage, check all variables. */
3564 && ! current_function_check_memory_usage)
3566 /* Automatic variable that can go in a register. */
3567 int unsignedp = TREE_UNSIGNED (type);
3568 enum machine_mode reg_mode
3569 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3571 DECL_RTL (decl) = gen_reg_rtx (reg_mode);
3572 mark_user_reg (DECL_RTL (decl));
3574 if (POINTER_TYPE_P (type))
3575 mark_reg_pointer (DECL_RTL (decl),
3576 (TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl)))
3580 else if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST
3581 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3582 && (TREE_INT_CST_HIGH (DECL_SIZE (decl)) != 0
3583 || (TREE_INT_CST_LOW (DECL_SIZE (decl))
3584 > STACK_CHECK_MAX_VAR_SIZE * BITS_PER_UNIT))))
3586 /* Variable of fixed size that goes on the stack. */
3590 /* If we previously made RTL for this decl, it must be an array
3591 whose size was determined by the initializer.
3592 The old address was a register; set that register now
3593 to the proper address. */
3594 if (DECL_RTL (decl) != 0)
3596 if (GET_CODE (DECL_RTL (decl)) != MEM
3597 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3599 oldaddr = XEXP (DECL_RTL (decl), 0);
3602 DECL_RTL (decl) = assign_temp (TREE_TYPE (decl), 1, 1, 1);
3603 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3604 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3606 /* Set alignment we actually gave this decl. */
3607 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3608 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3612 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3613 if (addr != oldaddr)
3614 emit_move_insn (oldaddr, addr);
3617 /* If this is a memory ref that contains aggregate components,
3618 mark it as such for cse and loop optimize. */
3619 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3620 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3622 /* If this is in memory because of -ffloat-store,
3623 set the volatile bit, to prevent optimizations from
3624 undoing the effects. */
3625 if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
3626 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3629 MEM_ALIAS_SET (DECL_RTL (decl)) = get_alias_set (decl);
3632 /* Dynamic-size object: must push space on the stack. */
3636 /* Record the stack pointer on entry to block, if have
3637 not already done so. */
3638 if (thisblock->data.block.stack_level == 0)
3640 do_pending_stack_adjust ();
3641 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3642 &thisblock->data.block.stack_level,
3643 thisblock->data.block.first_insn);
3644 stack_block_stack = thisblock;
3647 /* Compute the variable's size, in bytes. */
3648 size = expand_expr (size_binop (CEIL_DIV_EXPR,
3650 size_int (BITS_PER_UNIT)),
3651 NULL_RTX, VOIDmode, 0);
3654 /* Allocate space on the stack for the variable. Note that
3655 DECL_ALIGN says how the variable is to be aligned and we
3656 cannot use it to conclude anything about the alignment of
3658 address = allocate_dynamic_stack_space (size, NULL_RTX,
3659 TYPE_ALIGN (TREE_TYPE (decl)));
3661 /* Reference the variable indirect through that rtx. */
3662 DECL_RTL (decl) = gen_rtx_MEM (DECL_MODE (decl), address);
3664 /* If this is a memory ref that contains aggregate components,
3665 mark it as such for cse and loop optimize. */
3666 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3667 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3669 /* Indicate the alignment we actually gave this variable. */
3670 #ifdef STACK_BOUNDARY
3671 DECL_ALIGN (decl) = STACK_BOUNDARY;
3673 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3677 if (TREE_THIS_VOLATILE (decl))
3678 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3679 #if 0 /* A variable is not necessarily unchanging
3680 just because it is const. RTX_UNCHANGING_P
3681 means no change in the function,
3682 not merely no change in the variable's scope.
3683 It is correct to set RTX_UNCHANGING_P if the variable's scope
3684 is the whole function. There's no convenient way to test that. */
3685 if (TREE_READONLY (decl))
3686 RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
3689 /* If doing stupid register allocation, make sure life of any
3690 register variable starts here, at the start of its scope. */
3693 use_variable (DECL_RTL (decl));
3698 /* Emit code to perform the initialization of a declaration DECL. */
3701 expand_decl_init (decl)
3704 int was_used = TREE_USED (decl);
3706 /* If this is a CONST_DECL, we don't have to generate any code, but
3707 if DECL_INITIAL is a constant, call expand_expr to force TREE_CST_RTL
3708 to be set while in the obstack containing the constant. If we don't
3709 do this, we can lose if we have functions nested three deep and the middle
3710 function makes a CONST_DECL whose DECL_INITIAL is a STRING_CST while
3711 the innermost function is the first to expand that STRING_CST. */
3712 if (TREE_CODE (decl) == CONST_DECL)
3714 if (DECL_INITIAL (decl) && TREE_CONSTANT (DECL_INITIAL (decl)))
3715 expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
3716 EXPAND_INITIALIZER);
3720 if (TREE_STATIC (decl))
3723 /* Compute and store the initial value now. */
3725 if (DECL_INITIAL (decl) == error_mark_node)
3727 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3729 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3730 || code == POINTER_TYPE || code == REFERENCE_TYPE)
3731 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3735 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3737 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
3738 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
3742 /* Don't let the initialization count as "using" the variable. */
3743 TREE_USED (decl) = was_used;
3745 /* Free any temporaries we made while initializing the decl. */
3746 preserve_temp_slots (NULL_RTX);
3750 /* CLEANUP is an expression to be executed at exit from this binding contour;
3751 for example, in C++, it might call the destructor for this variable.
3753 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
3754 CLEANUP multiple times, and have the correct semantics. This
3755 happens in exception handling, for gotos, returns, breaks that
3756 leave the current scope.
3758 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3759 that is not associated with any particular variable. */
3762 expand_decl_cleanup (decl, cleanup)
3765 struct nesting *thisblock = block_stack;
3767 /* Error if we are not in any block. */
3771 /* Record the cleanup if there is one. */
3777 tree *cleanups = &thisblock->data.block.cleanups;
3778 int cond_context = conditional_context ();
3782 rtx flag = gen_reg_rtx (word_mode);
3787 emit_move_insn (flag, const0_rtx);
3788 set_flag_0 = get_insns ();
3791 thisblock->data.block.last_unconditional_cleanup
3792 = emit_insns_after (set_flag_0,
3793 thisblock->data.block.last_unconditional_cleanup);
3795 emit_move_insn (flag, const1_rtx);
3797 /* All cleanups must be on the function_obstack. */
3798 push_obstacks_nochange ();
3799 resume_temporary_allocation ();
3801 cond = build_decl (VAR_DECL, NULL_TREE, type_for_mode (word_mode, 1));
3802 DECL_RTL (cond) = flag;
3804 /* Conditionalize the cleanup. */
3805 cleanup = build (COND_EXPR, void_type_node,
3806 truthvalue_conversion (cond),
3807 cleanup, integer_zero_node);
3808 cleanup = fold (cleanup);
3812 cleanups = thisblock->data.block.cleanup_ptr;
3815 /* All cleanups must be on the function_obstack. */
3816 push_obstacks_nochange ();
3817 resume_temporary_allocation ();
3818 cleanup = unsave_expr (cleanup);
3821 t = *cleanups = temp_tree_cons (decl, cleanup, *cleanups);
3824 /* If this block has a cleanup, it belongs in stack_block_stack. */
3825 stack_block_stack = thisblock;
3832 /* If this was optimized so that there is no exception region for the
3833 cleanup, then mark the TREE_LIST node, so that we can later tell
3834 if we need to call expand_eh_region_end. */
3835 if (! using_eh_for_cleanups_p
3836 || expand_eh_region_start_tree (decl, cleanup))
3837 TREE_ADDRESSABLE (t) = 1;
3838 /* If that started a new EH region, we're in a new block. */
3839 thisblock = block_stack;
3846 thisblock->data.block.last_unconditional_cleanup
3847 = emit_insns_after (seq,
3848 thisblock->data.block.last_unconditional_cleanup);
3852 thisblock->data.block.last_unconditional_cleanup
3854 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
3860 /* Like expand_decl_cleanup, but suppress generating an exception handler
3861 to perform the cleanup. */
3864 expand_decl_cleanup_no_eh (decl, cleanup)
3867 int save_eh = using_eh_for_cleanups_p;
3870 using_eh_for_cleanups_p = 0;
3871 result = expand_decl_cleanup (decl, cleanup);
3872 using_eh_for_cleanups_p = save_eh;
3877 /* Arrange for the top element of the dynamic cleanup chain to be
3878 popped if we exit the current binding contour. DECL is the
3879 associated declaration, if any, otherwise NULL_TREE. If the
3880 current contour is left via an exception, then __sjthrow will pop
3881 the top element off the dynamic cleanup chain. The code that
3882 avoids doing the action we push into the cleanup chain in the
3883 exceptional case is contained in expand_cleanups.
3885 This routine is only used by expand_eh_region_start, and that is
3886 the only way in which an exception region should be started. This
3887 routine is only used when using the setjmp/longjmp codegen method
3888 for exception handling. */
3891 expand_dcc_cleanup (decl)
3894 struct nesting *thisblock = block_stack;
3897 /* Error if we are not in any block. */
3901 /* Record the cleanup for the dynamic handler chain. */
3903 /* All cleanups must be on the function_obstack. */
3904 push_obstacks_nochange ();
3905 resume_temporary_allocation ();
3906 cleanup = make_node (POPDCC_EXPR);
3909 /* Add the cleanup in a manner similar to expand_decl_cleanup. */
3910 thisblock->data.block.cleanups
3911 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3913 /* If this block has a cleanup, it belongs in stack_block_stack. */
3914 stack_block_stack = thisblock;
3918 /* Arrange for the top element of the dynamic handler chain to be
3919 popped if we exit the current binding contour. DECL is the
3920 associated declaration, if any, otherwise NULL_TREE. If the current
3921 contour is left via an exception, then __sjthrow will pop the top
3922 element off the dynamic handler chain. The code that avoids doing
3923 the action we push into the handler chain in the exceptional case
3924 is contained in expand_cleanups.
3926 This routine is only used by expand_eh_region_start, and that is
3927 the only way in which an exception region should be started. This
3928 routine is only used when using the setjmp/longjmp codegen method
3929 for exception handling. */
3932 expand_dhc_cleanup (decl)
3935 struct nesting *thisblock = block_stack;
3938 /* Error if we are not in any block. */
3942 /* Record the cleanup for the dynamic handler chain. */
3944 /* All cleanups must be on the function_obstack. */
3945 push_obstacks_nochange ();
3946 resume_temporary_allocation ();
3947 cleanup = make_node (POPDHC_EXPR);
3950 /* Add the cleanup in a manner similar to expand_decl_cleanup. */
3951 thisblock->data.block.cleanups
3952 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3954 /* If this block has a cleanup, it belongs in stack_block_stack. */
3955 stack_block_stack = thisblock;
3959 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3960 DECL_ELTS is the list of elements that belong to DECL's type.
3961 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3964 expand_anon_union_decl (decl, cleanup, decl_elts)
3965 tree decl, cleanup, decl_elts;
3967 struct nesting *thisblock = block_stack;
3971 expand_decl_cleanup (decl, cleanup);
3972 x = DECL_RTL (decl);
3976 tree decl_elt = TREE_VALUE (decl_elts);
3977 tree cleanup_elt = TREE_PURPOSE (decl_elts);
3978 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3980 /* Propagate the union's alignment to the elements. */
3981 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
3983 /* If the element has BLKmode and the union doesn't, the union is
3984 aligned such that the element doesn't need to have BLKmode, so
3985 change the element's mode to the appropriate one for its size. */
3986 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
3987 DECL_MODE (decl_elt) = mode
3988 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl_elt)),
3991 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3992 instead create a new MEM rtx with the proper mode. */
3993 if (GET_CODE (x) == MEM)
3995 if (mode == GET_MODE (x))
3996 DECL_RTL (decl_elt) = x;
3999 DECL_RTL (decl_elt) = gen_rtx_MEM (mode, copy_rtx (XEXP (x, 0)));
4000 MEM_COPY_ATTRIBUTES (DECL_RTL (decl_elt), x);
4001 RTX_UNCHANGING_P (DECL_RTL (decl_elt)) = RTX_UNCHANGING_P (x);
4004 else if (GET_CODE (x) == REG)
4006 if (mode == GET_MODE (x))
4007 DECL_RTL (decl_elt) = x;
4009 DECL_RTL (decl_elt) = gen_rtx_SUBREG (mode, x, 0);
4014 /* Record the cleanup if there is one. */
4017 thisblock->data.block.cleanups
4018 = temp_tree_cons (decl_elt, cleanup_elt,
4019 thisblock->data.block.cleanups);
4021 decl_elts = TREE_CHAIN (decl_elts);
4025 /* Expand a list of cleanups LIST.
4026 Elements may be expressions or may be nested lists.
4028 If DONT_DO is nonnull, then any list-element
4029 whose TREE_PURPOSE matches DONT_DO is omitted.
4030 This is sometimes used to avoid a cleanup associated with
4031 a value that is being returned out of the scope.
4033 If IN_FIXUP is non-zero, we are generating this cleanup for a fixup
4034 goto and handle protection regions specially in that case.
4036 If REACHABLE, we emit code, otherwise just inform the exception handling
4037 code about this finalization. */
4040 expand_cleanups (list, dont_do, in_fixup, reachable)
4047 for (tail = list; tail; tail = TREE_CHAIN (tail))
4048 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
4050 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4051 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
4056 tree cleanup = TREE_VALUE (tail);
4058 /* See expand_d{h,c}c_cleanup for why we avoid this. */
4059 if (TREE_CODE (cleanup) != POPDHC_EXPR
4060 && TREE_CODE (cleanup) != POPDCC_EXPR
4061 /* See expand_eh_region_start_tree for this case. */
4062 && ! TREE_ADDRESSABLE (tail))
4064 cleanup = protect_with_terminate (cleanup);
4065 expand_eh_region_end (cleanup);
4071 /* Cleanups may be run multiple times. For example,
4072 when exiting a binding contour, we expand the
4073 cleanups associated with that contour. When a goto
4074 within that binding contour has a target outside that
4075 contour, it will expand all cleanups from its scope to
4076 the target. Though the cleanups are expanded multiple
4077 times, the control paths are non-overlapping so the
4078 cleanups will not be executed twice. */
4080 /* We may need to protect fixups with rethrow regions. */
4081 int protect = (in_fixup && ! TREE_ADDRESSABLE (tail));
4084 expand_fixup_region_start ();
4086 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4088 expand_fixup_region_end (TREE_VALUE (tail));
4095 /* Mark when the context we are emitting RTL for as a conditional
4096 context, so that any cleanup actions we register with
4097 expand_decl_init will be properly conditionalized when those
4098 cleanup actions are later performed. Must be called before any
4099 expression (tree) is expanded that is within a conditional context. */
4102 start_cleanup_deferral ()
4104 /* block_stack can be NULL if we are inside the parameter list. It is
4105 OK to do nothing, because cleanups aren't possible here. */
4107 ++block_stack->data.block.conditional_code;
4110 /* Mark the end of a conditional region of code. Because cleanup
4111 deferrals may be nested, we may still be in a conditional region
4112 after we end the currently deferred cleanups, only after we end all
4113 deferred cleanups, are we back in unconditional code. */
4116 end_cleanup_deferral ()
4118 /* block_stack can be NULL if we are inside the parameter list. It is
4119 OK to do nothing, because cleanups aren't possible here. */
4121 --block_stack->data.block.conditional_code;
4124 /* Move all cleanups from the current block_stack
4125 to the containing block_stack, where they are assumed to
4126 have been created. If anything can cause a temporary to
4127 be created, but not expanded for more than one level of
4128 block_stacks, then this code will have to change. */
4133 struct nesting *block = block_stack;
4134 struct nesting *outer = block->next;
4136 outer->data.block.cleanups
4137 = chainon (block->data.block.cleanups,
4138 outer->data.block.cleanups);
4139 block->data.block.cleanups = 0;
4143 last_cleanup_this_contour ()
4145 if (block_stack == 0)
4148 return block_stack->data.block.cleanups;
4151 /* Return 1 if there are any pending cleanups at this point.
4152 If THIS_CONTOUR is nonzero, check the current contour as well.
4153 Otherwise, look only at the contours that enclose this one. */
4156 any_pending_cleanups (this_contour)
4159 struct nesting *block;
4161 if (block_stack == 0)
4164 if (this_contour && block_stack->data.block.cleanups != NULL)
4166 if (block_stack->data.block.cleanups == 0
4167 && block_stack->data.block.outer_cleanups == 0)
4170 for (block = block_stack->next; block; block = block->next)
4171 if (block->data.block.cleanups != 0)
4177 /* Enter a case (Pascal) or switch (C) statement.
4178 Push a block onto case_stack and nesting_stack
4179 to accumulate the case-labels that are seen
4180 and to record the labels generated for the statement.
4182 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4183 Otherwise, this construct is transparent for `exit_something'.
4185 EXPR is the index-expression to be dispatched on.
4186 TYPE is its nominal type. We could simply convert EXPR to this type,
4187 but instead we take short cuts. */
4190 expand_start_case (exit_flag, expr, type, printname)
4194 const char *printname;
4196 register struct nesting *thiscase = ALLOC_NESTING ();
4198 /* Make an entry on case_stack for the case we are entering. */
4200 thiscase->next = case_stack;
4201 thiscase->all = nesting_stack;
4202 thiscase->depth = ++nesting_depth;
4203 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4204 thiscase->data.case_stmt.case_list = 0;
4205 thiscase->data.case_stmt.index_expr = expr;
4206 thiscase->data.case_stmt.nominal_type = type;
4207 thiscase->data.case_stmt.default_label = 0;
4208 thiscase->data.case_stmt.num_ranges = 0;
4209 thiscase->data.case_stmt.printname = printname;
4210 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4211 case_stack = thiscase;
4212 nesting_stack = thiscase;
4214 do_pending_stack_adjust ();
4216 /* Make sure case_stmt.start points to something that won't
4217 need any transformation before expand_end_case. */
4218 if (GET_CODE (get_last_insn ()) != NOTE)
4219 emit_note (NULL_PTR, NOTE_INSN_DELETED);
4221 thiscase->data.case_stmt.start = get_last_insn ();
4223 start_cleanup_deferral ();
4227 /* Start a "dummy case statement" within which case labels are invalid
4228 and are not connected to any larger real case statement.
4229 This can be used if you don't want to let a case statement jump
4230 into the middle of certain kinds of constructs. */
4233 expand_start_case_dummy ()
4235 register struct nesting *thiscase = ALLOC_NESTING ();
4237 /* Make an entry on case_stack for the dummy. */
4239 thiscase->next = case_stack;
4240 thiscase->all = nesting_stack;
4241 thiscase->depth = ++nesting_depth;
4242 thiscase->exit_label = 0;
4243 thiscase->data.case_stmt.case_list = 0;
4244 thiscase->data.case_stmt.start = 0;
4245 thiscase->data.case_stmt.nominal_type = 0;
4246 thiscase->data.case_stmt.default_label = 0;
4247 thiscase->data.case_stmt.num_ranges = 0;
4248 case_stack = thiscase;
4249 nesting_stack = thiscase;
4250 start_cleanup_deferral ();
4253 /* End a dummy case statement. */
4256 expand_end_case_dummy ()
4258 end_cleanup_deferral ();
4259 POPSTACK (case_stack);
4262 /* Return the data type of the index-expression
4263 of the innermost case statement, or null if none. */
4266 case_index_expr_type ()
4269 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
4276 /* If this is the first label, warn if any insns have been emitted. */
4277 if (case_stack->data.case_stmt.line_number_status >= 0)
4281 restore_line_number_status
4282 (case_stack->data.case_stmt.line_number_status);
4283 case_stack->data.case_stmt.line_number_status = -1;
4285 for (insn = case_stack->data.case_stmt.start;
4287 insn = NEXT_INSN (insn))
4289 if (GET_CODE (insn) == CODE_LABEL)
4291 if (GET_CODE (insn) != NOTE
4292 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4295 insn = PREV_INSN (insn);
4296 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4298 /* If insn is zero, then there must have been a syntax error. */
4300 warning_with_file_and_line (NOTE_SOURCE_FILE(insn),
4301 NOTE_LINE_NUMBER(insn),
4302 "unreachable code at beginning of %s",
4303 case_stack->data.case_stmt.printname);
4310 /* Accumulate one case or default label inside a case or switch statement.
4311 VALUE is the value of the case (a null pointer, for a default label).
4312 The function CONVERTER, when applied to arguments T and V,
4313 converts the value V to the type T.
4315 If not currently inside a case or switch statement, return 1 and do
4316 nothing. The caller will print a language-specific error message.
4317 If VALUE is a duplicate or overlaps, return 2 and do nothing
4318 except store the (first) duplicate node in *DUPLICATE.
4319 If VALUE is out of range, return 3 and do nothing.
4320 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4321 Return 0 on success.
4323 Extended to handle range statements. */
4326 pushcase (value, converter, label, duplicate)
4327 register tree value;
4328 tree (*converter) PROTO((tree, tree));
4329 register tree label;
4335 /* Fail if not inside a real case statement. */
4336 if (! (case_stack && case_stack->data.case_stmt.start))
4339 if (stack_block_stack
4340 && stack_block_stack->depth > case_stack->depth)
4343 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4344 nominal_type = case_stack->data.case_stmt.nominal_type;
4346 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4347 if (index_type == error_mark_node)
4350 /* Convert VALUE to the type in which the comparisons are nominally done. */
4352 value = (*converter) (nominal_type, value);
4356 /* Fail if this value is out of range for the actual type of the index
4357 (which may be narrower than NOMINAL_TYPE). */
4358 if (value != 0 && ! int_fits_type_p (value, index_type))
4361 /* Fail if this is a duplicate or overlaps another entry. */
4364 if (case_stack->data.case_stmt.default_label != 0)
4366 *duplicate = case_stack->data.case_stmt.default_label;
4369 case_stack->data.case_stmt.default_label = label;
4372 return add_case_node (value, value, label, duplicate);
4374 expand_label (label);
4378 /* Like pushcase but this case applies to all values between VALUE1 and
4379 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4380 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4381 starts at VALUE1 and ends at the highest value of the index type.
4382 If both are NULL, this case applies to all values.
4384 The return value is the same as that of pushcase but there is one
4385 additional error code: 4 means the specified range was empty. */
4388 pushcase_range (value1, value2, converter, label, duplicate)
4389 register tree value1, value2;
4390 tree (*converter) PROTO((tree, tree));
4391 register tree label;
4397 /* Fail if not inside a real case statement. */
4398 if (! (case_stack && case_stack->data.case_stmt.start))
4401 if (stack_block_stack
4402 && stack_block_stack->depth > case_stack->depth)
4405 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4406 nominal_type = case_stack->data.case_stmt.nominal_type;
4408 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4409 if (index_type == error_mark_node)
4414 /* Convert VALUEs to type in which the comparisons are nominally done
4415 and replace any unspecified value with the corresponding bound. */
4417 value1 = TYPE_MIN_VALUE (index_type);
4419 value2 = TYPE_MAX_VALUE (index_type);
4421 /* Fail if the range is empty. Do this before any conversion since
4422 we want to allow out-of-range empty ranges. */
4423 if (value2 && tree_int_cst_lt (value2, value1))
4426 value1 = (*converter) (nominal_type, value1);
4428 /* If the max was unbounded, use the max of the nominal_type we are
4429 converting to. Do this after the < check above to suppress false
4432 value2 = TYPE_MAX_VALUE (nominal_type);
4433 value2 = (*converter) (nominal_type, value2);
4435 /* Fail if these values are out of range. */
4436 if (TREE_CONSTANT_OVERFLOW (value1)
4437 || ! int_fits_type_p (value1, index_type))
4440 if (TREE_CONSTANT_OVERFLOW (value2)
4441 || ! int_fits_type_p (value2, index_type))
4444 return add_case_node (value1, value2, label, duplicate);
4447 /* Do the actual insertion of a case label for pushcase and pushcase_range
4448 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4449 slowdown for large switch statements. */
4452 add_case_node (low, high, label, duplicate)
4457 struct case_node *p, **q, *r;
4459 q = &case_stack->data.case_stmt.case_list;
4466 /* Keep going past elements distinctly greater than HIGH. */
4467 if (tree_int_cst_lt (high, p->low))
4470 /* or distinctly less than LOW. */
4471 else if (tree_int_cst_lt (p->high, low))
4476 /* We have an overlap; this is an error. */
4477 *duplicate = p->code_label;
4482 /* Add this label to the chain, and succeed.
4483 Copy LOW, HIGH so they are on temporary rather than momentary
4484 obstack and will thus survive till the end of the case statement. */
4486 r = (struct case_node *) oballoc (sizeof (struct case_node));
4487 r->low = copy_node (low);
4489 /* If the bounds are equal, turn this into the one-value case. */
4491 if (tree_int_cst_equal (low, high))
4495 r->high = copy_node (high);
4496 case_stack->data.case_stmt.num_ranges++;
4499 r->code_label = label;
4500 expand_label (label);
4510 struct case_node *s;
4516 if (! (b = p->balance))
4517 /* Growth propagation from left side. */
4524 if ((p->left = s = r->right))
4533 if ((r->parent = s))
4541 case_stack->data.case_stmt.case_list = r;
4544 /* r->balance == +1 */
4549 struct case_node *t = r->right;
4551 if ((p->left = s = t->right))
4555 if ((r->right = s = t->left))
4569 if ((t->parent = s))
4577 case_stack->data.case_stmt.case_list = t;
4584 /* p->balance == +1; growth of left side balances the node. */
4594 if (! (b = p->balance))
4595 /* Growth propagation from right side. */
4603 if ((p->right = s = r->left))
4611 if ((r->parent = s))
4620 case_stack->data.case_stmt.case_list = r;
4624 /* r->balance == -1 */
4628 struct case_node *t = r->left;
4630 if ((p->right = s = t->left))
4635 if ((r->left = s = t->right))
4649 if ((t->parent = s))
4658 case_stack->data.case_stmt.case_list = t;
4664 /* p->balance == -1; growth of right side balances the node. */
4678 /* Returns the number of possible values of TYPE.
4679 Returns -1 if the number is unknown or variable.
4680 Returns -2 if the number does not fit in a HOST_WIDE_INT.
4681 Sets *SPARENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4682 do not increase monotonically (there may be duplicates);
4683 to 1 if the values increase monotonically, but not always by 1;
4684 otherwise sets it to 0. */
4687 all_cases_count (type, spareness)
4691 HOST_WIDE_INT count;
4694 switch (TREE_CODE (type))
4701 count = 1 << BITS_PER_UNIT;
4705 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4706 || TYPE_MAX_VALUE (type) == NULL
4707 || TREE_CODE (TYPE_MAX_VALUE (type)) != INTEGER_CST)
4712 = TREE_INT_CST_LOW (TYPE_MAX_VALUE (type))
4713 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + 1
4714 but with overflow checking. */
4715 tree mint = TYPE_MIN_VALUE (type);
4716 tree maxt = TYPE_MAX_VALUE (type);
4717 HOST_WIDE_INT lo, hi;
4718 neg_double(TREE_INT_CST_LOW (mint), TREE_INT_CST_HIGH (mint),
4720 add_double(TREE_INT_CST_LOW (maxt), TREE_INT_CST_HIGH (maxt),
4722 add_double (lo, hi, 1, 0, &lo, &hi);
4723 if (hi != 0 || lo < 0)
4730 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4732 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4733 || TREE_CODE (TREE_VALUE (t)) != INTEGER_CST
4734 || TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + count
4735 != TREE_INT_CST_LOW (TREE_VALUE (t)))
4739 if (*spareness == 1)
4741 tree prev = TREE_VALUE (TYPE_VALUES (type));
4742 for (t = TYPE_VALUES (type); t = TREE_CHAIN (t), t != NULL_TREE; )
4744 if (! tree_int_cst_lt (prev, TREE_VALUE (t)))
4749 prev = TREE_VALUE (t);
4758 #define BITARRAY_TEST(ARRAY, INDEX) \
4759 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4760 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4761 #define BITARRAY_SET(ARRAY, INDEX) \
4762 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4763 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4765 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4766 with the case values we have seen, assuming the case expression
4768 SPARSENESS is as determined by all_cases_count.
4770 The time needed is proportional to COUNT, unless
4771 SPARSENESS is 2, in which case quadratic time is needed. */
4774 mark_seen_cases (type, cases_seen, count, sparseness)
4776 unsigned char *cases_seen;
4780 tree next_node_to_try = NULL_TREE;
4781 long next_node_offset = 0;
4783 register struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4784 tree val = make_node (INTEGER_CST);
4785 TREE_TYPE (val) = type;
4788 else if (sparseness == 2)
4793 /* This less efficient loop is only needed to handle
4794 duplicate case values (multiple enum constants
4795 with the same value). */
4796 TREE_TYPE (val) = TREE_TYPE (root->low);
4797 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4798 t = TREE_CHAIN (t), xlo++)
4800 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4801 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4805 /* Keep going past elements distinctly greater than VAL. */
4806 if (tree_int_cst_lt (val, n->low))
4809 /* or distinctly less than VAL. */
4810 else if (tree_int_cst_lt (n->high, val))
4815 /* We have found a matching range. */
4816 BITARRAY_SET (cases_seen, xlo);
4826 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
4827 for (n = root; n; n = n->right)
4829 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4830 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4831 while ( ! tree_int_cst_lt (n->high, val))
4833 /* Calculate (into xlo) the "offset" of the integer (val).
4834 The element with lowest value has offset 0, the next smallest
4835 element has offset 1, etc. */
4837 HOST_WIDE_INT xlo, xhi;
4839 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4841 /* The TYPE_VALUES will be in increasing order, so
4842 starting searching where we last ended. */
4843 t = next_node_to_try;
4844 xlo = next_node_offset;
4850 t = TYPE_VALUES (type);
4853 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4855 next_node_to_try = TREE_CHAIN (t);
4856 next_node_offset = xlo + 1;
4861 if (t == next_node_to_try)
4870 t = TYPE_MIN_VALUE (type);
4872 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
4876 add_double (xlo, xhi,
4877 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4881 if (xhi == 0 && xlo >= 0 && xlo < count)
4882 BITARRAY_SET (cases_seen, xlo);
4883 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4885 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
4891 /* Called when the index of a switch statement is an enumerated type
4892 and there is no default label.
4894 Checks that all enumeration literals are covered by the case
4895 expressions of a switch. Also, warn if there are any extra
4896 switch cases that are *not* elements of the enumerated type.
4898 If all enumeration literals were covered by the case expressions,
4899 turn one of the expressions into the default expression since it should
4900 not be possible to fall through such a switch. */
4903 check_for_full_enumeration_handling (type)
4906 register struct case_node *n;
4907 register tree chain;
4908 #if 0 /* variable used by 'if 0'ed code below. */
4909 register struct case_node **l;
4913 /* True iff the selector type is a numbered set mode. */
4916 /* The number of possible selector values. */
4919 /* For each possible selector value. a one iff it has been matched
4920 by a case value alternative. */
4921 unsigned char *cases_seen;
4923 /* The allocated size of cases_seen, in chars. */
4929 size = all_cases_count (type, &sparseness);
4930 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
4932 if (size > 0 && size < 600000
4933 /* We deliberately use malloc here - not xmalloc. */
4934 && (cases_seen = (unsigned char *) malloc (bytes_needed)) != NULL)
4937 tree v = TYPE_VALUES (type);
4938 bzero (cases_seen, bytes_needed);
4940 /* The time complexity of this code is normally O(N), where
4941 N being the number of members in the enumerated type.
4942 However, if type is a ENUMERAL_TYPE whose values do not
4943 increase monotonically, O(N*log(N)) time may be needed. */
4945 mark_seen_cases (type, cases_seen, size, sparseness);
4947 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
4949 if (BITARRAY_TEST(cases_seen, i) == 0)
4950 warning ("enumeration value `%s' not handled in switch",
4951 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
4957 /* Now we go the other way around; we warn if there are case
4958 expressions that don't correspond to enumerators. This can
4959 occur since C and C++ don't enforce type-checking of
4960 assignments to enumeration variables. */
4962 if (case_stack->data.case_stmt.case_list
4963 && case_stack->data.case_stmt.case_list->left)
4964 case_stack->data.case_stmt.case_list
4965 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
4967 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
4969 for (chain = TYPE_VALUES (type);
4970 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
4971 chain = TREE_CHAIN (chain))
4976 if (TYPE_NAME (type) == 0)
4977 warning ("case value `%ld' not in enumerated type",
4978 (long) TREE_INT_CST_LOW (n->low));
4980 warning ("case value `%ld' not in enumerated type `%s'",
4981 (long) TREE_INT_CST_LOW (n->low),
4982 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4985 : DECL_NAME (TYPE_NAME (type))));
4987 if (!tree_int_cst_equal (n->low, n->high))
4989 for (chain = TYPE_VALUES (type);
4990 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
4991 chain = TREE_CHAIN (chain))
4996 if (TYPE_NAME (type) == 0)
4997 warning ("case value `%ld' not in enumerated type",
4998 (long) TREE_INT_CST_LOW (n->high));
5000 warning ("case value `%ld' not in enumerated type `%s'",
5001 (long) TREE_INT_CST_LOW (n->high),
5002 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5005 : DECL_NAME (TYPE_NAME (type))));
5011 /* ??? This optimization is disabled because it causes valid programs to
5012 fail. ANSI C does not guarantee that an expression with enum type
5013 will have a value that is the same as one of the enumeration literals. */
5015 /* If all values were found as case labels, make one of them the default
5016 label. Thus, this switch will never fall through. We arbitrarily pick
5017 the last one to make the default since this is likely the most
5018 efficient choice. */
5022 for (l = &case_stack->data.case_stmt.case_list;
5027 case_stack->data.case_stmt.default_label = (*l)->code_label;
5034 /* Terminate a case (Pascal) or switch (C) statement
5035 in which ORIG_INDEX is the expression to be tested.
5036 Generate the code to test it and jump to the right place. */
5039 expand_end_case (orig_index)
5042 tree minval = NULL_TREE, maxval = NULL_TREE, range, orig_minval;
5043 rtx default_label = 0;
5044 register struct case_node *n;
5052 register struct nesting *thiscase = case_stack;
5053 tree index_expr, index_type;
5056 table_label = gen_label_rtx ();
5057 index_expr = thiscase->data.case_stmt.index_expr;
5058 index_type = TREE_TYPE (index_expr);
5059 unsignedp = TREE_UNSIGNED (index_type);
5061 do_pending_stack_adjust ();
5063 /* This might get an spurious warning in the presence of a syntax error;
5064 it could be fixed by moving the call to check_seenlabel after the
5065 check for error_mark_node, and copying the code of check_seenlabel that
5066 deals with case_stack->data.case_stmt.line_number_status /
5067 restore_line_number_status in front of the call to end_cleanup_deferral;
5068 However, this might miss some useful warnings in the presence of
5069 non-syntax errors. */
5072 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5073 if (index_type != error_mark_node)
5075 /* If switch expression was an enumerated type, check that all
5076 enumeration literals are covered by the cases.
5077 No sense trying this if there's a default case, however. */
5079 if (!thiscase->data.case_stmt.default_label
5080 && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
5081 && TREE_CODE (index_expr) != INTEGER_CST)
5082 check_for_full_enumeration_handling (TREE_TYPE (orig_index));
5084 /* If we don't have a default-label, create one here,
5085 after the body of the switch. */
5086 if (thiscase->data.case_stmt.default_label == 0)
5088 thiscase->data.case_stmt.default_label
5089 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5090 expand_label (thiscase->data.case_stmt.default_label);
5092 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5094 before_case = get_last_insn ();
5096 if (thiscase->data.case_stmt.case_list
5097 && thiscase->data.case_stmt.case_list->left)
5098 thiscase->data.case_stmt.case_list
5099 = case_tree2list(thiscase->data.case_stmt.case_list, 0);
5101 /* Simplify the case-list before we count it. */
5102 group_case_nodes (thiscase->data.case_stmt.case_list);
5104 /* Get upper and lower bounds of case values.
5105 Also convert all the case values to the index expr's data type. */
5108 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5110 /* Check low and high label values are integers. */
5111 if (TREE_CODE (n->low) != INTEGER_CST)
5113 if (TREE_CODE (n->high) != INTEGER_CST)
5116 n->low = convert (index_type, n->low);
5117 n->high = convert (index_type, n->high);
5119 /* Count the elements and track the largest and smallest
5120 of them (treating them as signed even if they are not). */
5128 if (INT_CST_LT (n->low, minval))
5130 if (INT_CST_LT (maxval, n->high))
5133 /* A range counts double, since it requires two compares. */
5134 if (! tree_int_cst_equal (n->low, n->high))
5138 orig_minval = minval;
5140 /* Compute span of values. */
5142 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5144 end_cleanup_deferral ();
5148 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5150 emit_jump (default_label);
5153 /* If range of values is much bigger than number of values,
5154 make a sequence of conditional branches instead of a dispatch.
5155 If the switch-index is a constant, do it this way
5156 because we can optimize it. */
5158 #ifndef CASE_VALUES_THRESHOLD
5160 #define CASE_VALUES_THRESHOLD (HAVE_casesi ? 4 : 5)
5162 /* If machine does not have a case insn that compares the
5163 bounds, this means extra overhead for dispatch tables
5164 which raises the threshold for using them. */
5165 #define CASE_VALUES_THRESHOLD 5
5166 #endif /* HAVE_casesi */
5167 #endif /* CASE_VALUES_THRESHOLD */
5169 else if (TREE_INT_CST_HIGH (range) != 0
5170 || count < (unsigned int) CASE_VALUES_THRESHOLD
5171 || ((unsigned HOST_WIDE_INT) (TREE_INT_CST_LOW (range))
5173 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5176 || TREE_CODE (index_expr) == INTEGER_CST
5177 /* These will reduce to a constant. */
5178 || (TREE_CODE (index_expr) == CALL_EXPR
5179 && TREE_CODE (TREE_OPERAND (index_expr, 0)) == ADDR_EXPR
5180 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == FUNCTION_DECL
5181 && DECL_FUNCTION_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_CLASSIFY_TYPE)
5182 || (TREE_CODE (index_expr) == COMPOUND_EXPR
5183 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
5185 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5187 /* If the index is a short or char that we do not have
5188 an insn to handle comparisons directly, convert it to
5189 a full integer now, rather than letting each comparison
5190 generate the conversion. */
5192 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5193 && (cmp_optab->handlers[(int) GET_MODE(index)].insn_code
5194 == CODE_FOR_nothing))
5196 enum machine_mode wider_mode;
5197 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5198 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5199 if (cmp_optab->handlers[(int) wider_mode].insn_code
5200 != CODE_FOR_nothing)
5202 index = convert_to_mode (wider_mode, index, unsignedp);
5208 do_pending_stack_adjust ();
5210 index = protect_from_queue (index, 0);
5211 if (GET_CODE (index) == MEM)
5212 index = copy_to_reg (index);
5213 if (GET_CODE (index) == CONST_INT
5214 || TREE_CODE (index_expr) == INTEGER_CST)
5216 /* Make a tree node with the proper constant value
5217 if we don't already have one. */
5218 if (TREE_CODE (index_expr) != INTEGER_CST)
5221 = build_int_2 (INTVAL (index),
5222 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5223 index_expr = convert (index_type, index_expr);
5226 /* For constant index expressions we need only
5227 issue a unconditional branch to the appropriate
5228 target code. The job of removing any unreachable
5229 code is left to the optimisation phase if the
5230 "-O" option is specified. */
5231 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5232 if (! tree_int_cst_lt (index_expr, n->low)
5233 && ! tree_int_cst_lt (n->high, index_expr))
5237 emit_jump (label_rtx (n->code_label));
5239 emit_jump (default_label);
5243 /* If the index expression is not constant we generate
5244 a binary decision tree to select the appropriate
5245 target code. This is done as follows:
5247 The list of cases is rearranged into a binary tree,
5248 nearly optimal assuming equal probability for each case.
5250 The tree is transformed into RTL, eliminating
5251 redundant test conditions at the same time.
5253 If program flow could reach the end of the
5254 decision tree an unconditional jump to the
5255 default code is emitted. */
5258 = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
5259 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5260 balance_case_nodes (&thiscase->data.case_stmt.case_list,
5262 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5263 default_label, index_type);
5264 emit_jump_if_reachable (default_label);
5273 enum machine_mode index_mode = SImode;
5274 int index_bits = GET_MODE_BITSIZE (index_mode);
5276 enum machine_mode op_mode;
5278 /* Convert the index to SImode. */
5279 if (GET_MODE_BITSIZE (TYPE_MODE (index_type))
5280 > GET_MODE_BITSIZE (index_mode))
5282 enum machine_mode omode = TYPE_MODE (index_type);
5283 rtx rangertx = expand_expr (range, NULL_RTX, VOIDmode, 0);
5285 /* We must handle the endpoints in the original mode. */
5286 index_expr = build (MINUS_EXPR, index_type,
5287 index_expr, minval);
5288 minval = integer_zero_node;
5289 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5290 emit_cmp_and_jump_insns (rangertx, index, LTU, NULL_RTX,
5291 omode, 1, 0, default_label);
5292 /* Now we can safely truncate. */
5293 index = convert_to_mode (index_mode, index, 0);
5297 if (TYPE_MODE (index_type) != index_mode)
5299 index_expr = convert (type_for_size (index_bits, 0),
5301 index_type = TREE_TYPE (index_expr);
5304 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5307 index = protect_from_queue (index, 0);
5308 do_pending_stack_adjust ();
5310 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][0];
5311 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][0])
5313 index = copy_to_mode_reg (op_mode, index);
5315 op1 = expand_expr (minval, NULL_RTX, VOIDmode, 0);
5317 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][1];
5318 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][1])
5320 op1 = copy_to_mode_reg (op_mode, op1);
5322 op2 = expand_expr (range, NULL_RTX, VOIDmode, 0);
5324 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][2];
5325 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][2])
5327 op2 = copy_to_mode_reg (op_mode, op2);
5329 emit_jump_insn (gen_casesi (index, op1, op2,
5330 table_label, default_label));
5334 #ifdef HAVE_tablejump
5335 if (! win && HAVE_tablejump)
5337 index_expr = convert (thiscase->data.case_stmt.nominal_type,
5338 fold (build (MINUS_EXPR, index_type,
5339 index_expr, minval)));
5340 index_type = TREE_TYPE (index_expr);
5341 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5343 index = protect_from_queue (index, 0);
5344 do_pending_stack_adjust ();
5346 do_tablejump (index, TYPE_MODE (index_type),
5347 expand_expr (range, NULL_RTX, VOIDmode, 0),
5348 table_label, default_label);
5355 /* Get table of labels to jump to, in order of case index. */
5357 ncases = TREE_INT_CST_LOW (range) + 1;
5358 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5359 bzero ((char *) labelvec, ncases * sizeof (rtx));
5361 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5363 register HOST_WIDE_INT i
5364 = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
5369 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5370 if (i + TREE_INT_CST_LOW (orig_minval)
5371 == TREE_INT_CST_LOW (n->high))
5377 /* Fill in the gaps with the default. */
5378 for (i = 0; i < ncases; i++)
5379 if (labelvec[i] == 0)
5380 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5382 /* Output the table */
5383 emit_label (table_label);
5385 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5386 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5387 gen_rtx_LABEL_REF (Pmode, table_label),
5388 gen_rtvec_v (ncases, labelvec),
5389 const0_rtx, const0_rtx, 0));
5391 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5392 gen_rtvec_v (ncases, labelvec)));
5394 /* If the case insn drops through the table,
5395 after the table we must jump to the default-label.
5396 Otherwise record no drop-through after the table. */
5397 #ifdef CASE_DROPS_THROUGH
5398 emit_jump (default_label);
5404 before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
5405 reorder_insns (before_case, get_last_insn (),
5406 thiscase->data.case_stmt.start);
5409 end_cleanup_deferral ();
5411 if (thiscase->exit_label)
5412 emit_label (thiscase->exit_label);
5414 POPSTACK (case_stack);
5419 /* Convert the tree NODE into a list linked by the right field, with the left
5420 field zeroed. RIGHT is used for recursion; it is a list to be placed
5421 rightmost in the resulting list. */
5423 static struct case_node *
5424 case_tree2list (node, right)
5425 struct case_node *node, *right;
5427 struct case_node *left;
5430 right = case_tree2list (node->right, right);
5432 node->right = right;
5433 if ((left = node->left))
5436 return case_tree2list (left, node);
5442 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5445 do_jump_if_equal (op1, op2, label, unsignedp)
5446 rtx op1, op2, label;
5449 if (GET_CODE (op1) == CONST_INT
5450 && GET_CODE (op2) == CONST_INT)
5452 if (INTVAL (op1) == INTVAL (op2))
5457 enum machine_mode mode = GET_MODE (op1);
5458 if (mode == VOIDmode)
5459 mode = GET_MODE (op2);
5460 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX, mode, unsignedp,
5465 /* Not all case values are encountered equally. This function
5466 uses a heuristic to weight case labels, in cases where that
5467 looks like a reasonable thing to do.
5469 Right now, all we try to guess is text, and we establish the
5472 chars above space: 16
5481 If we find any cases in the switch that are not either -1 or in the range
5482 of valid ASCII characters, or are control characters other than those
5483 commonly used with "\", don't treat this switch scanning text.
5485 Return 1 if these nodes are suitable for cost estimation, otherwise
5489 estimate_case_costs (node)
5492 tree min_ascii = build_int_2 (-1, -1);
5493 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5497 /* If we haven't already made the cost table, make it now. Note that the
5498 lower bound of the table is -1, not zero. */
5500 if (cost_table == NULL)
5502 cost_table = ((short *) xmalloc (129 * sizeof (short))) + 1;
5503 bzero ((char *) (cost_table - 1), 129 * sizeof (short));
5505 for (i = 0; i < 128; i++)
5509 else if (ISPUNCT (i))
5511 else if (ISCNTRL (i))
5515 cost_table[' '] = 8;
5516 cost_table['\t'] = 4;
5517 cost_table['\0'] = 4;
5518 cost_table['\n'] = 2;
5519 cost_table['\f'] = 1;
5520 cost_table['\v'] = 1;
5521 cost_table['\b'] = 1;
5524 /* See if all the case expressions look like text. It is text if the
5525 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5526 as signed arithmetic since we don't want to ever access cost_table with a
5527 value less than -1. Also check that none of the constants in a range
5528 are strange control characters. */
5530 for (n = node; n; n = n->right)
5532 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5535 for (i = TREE_INT_CST_LOW (n->low); i <= TREE_INT_CST_LOW (n->high); i++)
5536 if (cost_table[i] < 0)
5540 /* All interesting values are within the range of interesting
5541 ASCII characters. */
5545 /* Scan an ordered list of case nodes
5546 combining those with consecutive values or ranges.
5548 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5551 group_case_nodes (head)
5554 case_node_ptr node = head;
5558 rtx lb = next_real_insn (label_rtx (node->code_label));
5560 case_node_ptr np = node;
5562 /* Try to group the successors of NODE with NODE. */
5563 while (((np = np->right) != 0)
5564 /* Do they jump to the same place? */
5565 && ((lb2 = next_real_insn (label_rtx (np->code_label))) == lb
5566 || (lb != 0 && lb2 != 0
5567 && simplejump_p (lb)
5568 && simplejump_p (lb2)
5569 && rtx_equal_p (SET_SRC (PATTERN (lb)),
5570 SET_SRC (PATTERN (lb2)))))
5571 /* Are their ranges consecutive? */
5572 && tree_int_cst_equal (np->low,
5573 fold (build (PLUS_EXPR,
5574 TREE_TYPE (node->high),
5577 /* An overflow is not consecutive. */
5578 && tree_int_cst_lt (node->high,
5579 fold (build (PLUS_EXPR,
5580 TREE_TYPE (node->high),
5582 integer_one_node))))
5584 node->high = np->high;
5586 /* NP is the first node after NODE which can't be grouped with it.
5587 Delete the nodes in between, and move on to that node. */
5593 /* Take an ordered list of case nodes
5594 and transform them into a near optimal binary tree,
5595 on the assumption that any target code selection value is as
5596 likely as any other.
5598 The transformation is performed by splitting the ordered
5599 list into two equal sections plus a pivot. The parts are
5600 then attached to the pivot as left and right branches. Each
5601 branch is then transformed recursively. */
5604 balance_case_nodes (head, parent)
5605 case_node_ptr *head;
5606 case_node_ptr parent;
5608 register case_node_ptr np;
5616 register case_node_ptr *npp;
5619 /* Count the number of entries on branch. Also count the ranges. */
5623 if (!tree_int_cst_equal (np->low, np->high))
5627 cost += cost_table[TREE_INT_CST_LOW (np->high)];
5631 cost += cost_table[TREE_INT_CST_LOW (np->low)];
5639 /* Split this list if it is long enough for that to help. */
5644 /* Find the place in the list that bisects the list's total cost,
5645 Here I gets half the total cost. */
5650 /* Skip nodes while their cost does not reach that amount. */
5651 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5652 i -= cost_table[TREE_INT_CST_LOW ((*npp)->high)];
5653 i -= cost_table[TREE_INT_CST_LOW ((*npp)->low)];
5656 npp = &(*npp)->right;
5661 /* Leave this branch lopsided, but optimize left-hand
5662 side and fill in `parent' fields for right-hand side. */
5664 np->parent = parent;
5665 balance_case_nodes (&np->left, np);
5666 for (; np->right; np = np->right)
5667 np->right->parent = np;
5671 /* If there are just three nodes, split at the middle one. */
5673 npp = &(*npp)->right;
5676 /* Find the place in the list that bisects the list's total cost,
5677 where ranges count as 2.
5678 Here I gets half the total cost. */
5679 i = (i + ranges + 1) / 2;
5682 /* Skip nodes while their cost does not reach that amount. */
5683 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5688 npp = &(*npp)->right;
5693 np->parent = parent;
5696 /* Optimize each of the two split parts. */
5697 balance_case_nodes (&np->left, np);
5698 balance_case_nodes (&np->right, np);
5702 /* Else leave this branch as one level,
5703 but fill in `parent' fields. */
5705 np->parent = parent;
5706 for (; np->right; np = np->right)
5707 np->right->parent = np;
5712 /* Search the parent sections of the case node tree
5713 to see if a test for the lower bound of NODE would be redundant.
5714 INDEX_TYPE is the type of the index expression.
5716 The instructions to generate the case decision tree are
5717 output in the same order as nodes are processed so it is
5718 known that if a parent node checks the range of the current
5719 node minus one that the current node is bounded at its lower
5720 span. Thus the test would be redundant. */
5723 node_has_low_bound (node, index_type)
5728 case_node_ptr pnode;
5730 /* If the lower bound of this node is the lowest value in the index type,
5731 we need not test it. */
5733 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5736 /* If this node has a left branch, the value at the left must be less
5737 than that at this node, so it cannot be bounded at the bottom and
5738 we need not bother testing any further. */
5743 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5744 node->low, integer_one_node));
5746 /* If the subtraction above overflowed, we can't verify anything.
5747 Otherwise, look for a parent that tests our value - 1. */
5749 if (! tree_int_cst_lt (low_minus_one, node->low))
5752 for (pnode = node->parent; pnode; pnode = pnode->parent)
5753 if (tree_int_cst_equal (low_minus_one, pnode->high))
5759 /* Search the parent sections of the case node tree
5760 to see if a test for the upper bound of NODE would be redundant.
5761 INDEX_TYPE is the type of the index expression.
5763 The instructions to generate the case decision tree are
5764 output in the same order as nodes are processed so it is
5765 known that if a parent node checks the range of the current
5766 node plus one that the current node is bounded at its upper
5767 span. Thus the test would be redundant. */
5770 node_has_high_bound (node, index_type)
5775 case_node_ptr pnode;
5777 /* If there is no upper bound, obviously no test is needed. */
5779 if (TYPE_MAX_VALUE (index_type) == NULL)
5782 /* If the upper bound of this node is the highest value in the type
5783 of the index expression, we need not test against it. */
5785 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5788 /* If this node has a right branch, the value at the right must be greater
5789 than that at this node, so it cannot be bounded at the top and
5790 we need not bother testing any further. */
5795 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5796 node->high, integer_one_node));
5798 /* If the addition above overflowed, we can't verify anything.
5799 Otherwise, look for a parent that tests our value + 1. */
5801 if (! tree_int_cst_lt (node->high, high_plus_one))
5804 for (pnode = node->parent; pnode; pnode = pnode->parent)
5805 if (tree_int_cst_equal (high_plus_one, pnode->low))
5811 /* Search the parent sections of the
5812 case node tree to see if both tests for the upper and lower
5813 bounds of NODE would be redundant. */
5816 node_is_bounded (node, index_type)
5820 return (node_has_low_bound (node, index_type)
5821 && node_has_high_bound (node, index_type));
5824 /* Emit an unconditional jump to LABEL unless it would be dead code. */
5827 emit_jump_if_reachable (label)
5830 if (GET_CODE (get_last_insn ()) != BARRIER)
5834 /* Emit step-by-step code to select a case for the value of INDEX.
5835 The thus generated decision tree follows the form of the
5836 case-node binary tree NODE, whose nodes represent test conditions.
5837 INDEX_TYPE is the type of the index of the switch.
5839 Care is taken to prune redundant tests from the decision tree
5840 by detecting any boundary conditions already checked by
5841 emitted rtx. (See node_has_high_bound, node_has_low_bound
5842 and node_is_bounded, above.)
5844 Where the test conditions can be shown to be redundant we emit
5845 an unconditional jump to the target code. As a further
5846 optimization, the subordinates of a tree node are examined to
5847 check for bounded nodes. In this case conditional and/or
5848 unconditional jumps as a result of the boundary check for the
5849 current node are arranged to target the subordinates associated
5850 code for out of bound conditions on the current node.
5852 We can assume that when control reaches the code generated here,
5853 the index value has already been compared with the parents
5854 of this node, and determined to be on the same side of each parent
5855 as this node is. Thus, if this node tests for the value 51,
5856 and a parent tested for 52, we don't need to consider
5857 the possibility of a value greater than 51. If another parent
5858 tests for the value 50, then this node need not test anything. */
5861 emit_case_nodes (index, node, default_label, index_type)
5867 /* If INDEX has an unsigned type, we must make unsigned branches. */
5868 int unsignedp = TREE_UNSIGNED (index_type);
5869 typedef rtx rtx_fn ();
5870 enum machine_mode mode = GET_MODE (index);
5872 /* See if our parents have already tested everything for us.
5873 If they have, emit an unconditional jump for this node. */
5874 if (node_is_bounded (node, index_type))
5875 emit_jump (label_rtx (node->code_label));
5877 else if (tree_int_cst_equal (node->low, node->high))
5879 /* Node is single valued. First see if the index expression matches
5880 this node and then check our children, if any. */
5882 do_jump_if_equal (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5883 label_rtx (node->code_label), unsignedp);
5885 if (node->right != 0 && node->left != 0)
5887 /* This node has children on both sides.
5888 Dispatch to one side or the other
5889 by comparing the index value with this node's value.
5890 If one subtree is bounded, check that one first,
5891 so we can avoid real branches in the tree. */
5893 if (node_is_bounded (node->right, index_type))
5895 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
5897 GT, NULL_RTX, mode, unsignedp, 0,
5898 label_rtx (node->right->code_label));
5899 emit_case_nodes (index, node->left, default_label, index_type);
5902 else if (node_is_bounded (node->left, index_type))
5904 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
5906 LT, NULL_RTX, mode, unsignedp, 0,
5907 label_rtx (node->left->code_label));
5908 emit_case_nodes (index, node->right, default_label, index_type);
5913 /* Neither node is bounded. First distinguish the two sides;
5914 then emit the code for one side at a time. */
5917 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5919 /* See if the value is on the right. */
5920 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
5922 GT, NULL_RTX, mode, unsignedp, 0,
5923 label_rtx (test_label));
5925 /* Value must be on the left.
5926 Handle the left-hand subtree. */
5927 emit_case_nodes (index, node->left, default_label, index_type);
5928 /* If left-hand subtree does nothing,
5930 emit_jump_if_reachable (default_label);
5932 /* Code branches here for the right-hand subtree. */
5933 expand_label (test_label);
5934 emit_case_nodes (index, node->right, default_label, index_type);
5938 else if (node->right != 0 && node->left == 0)
5940 /* Here we have a right child but no left so we issue conditional
5941 branch to default and process the right child.
5943 Omit the conditional branch to default if we it avoid only one
5944 right child; it costs too much space to save so little time. */
5946 if (node->right->right || node->right->left
5947 || !tree_int_cst_equal (node->right->low, node->right->high))
5949 if (!node_has_low_bound (node, index_type))
5951 emit_cmp_and_jump_insns (index, expand_expr (node->high,
5954 LT, NULL_RTX, mode, unsignedp, 0,
5958 emit_case_nodes (index, node->right, default_label, index_type);
5961 /* We cannot process node->right normally
5962 since we haven't ruled out the numbers less than
5963 this node's value. So handle node->right explicitly. */
5964 do_jump_if_equal (index,
5965 expand_expr (node->right->low, NULL_RTX,
5967 label_rtx (node->right->code_label), unsignedp);
5970 else if (node->right == 0 && node->left != 0)
5972 /* Just one subtree, on the left. */
5974 #if 0 /* The following code and comment were formerly part
5975 of the condition here, but they didn't work
5976 and I don't understand what the idea was. -- rms. */
5977 /* If our "most probable entry" is less probable
5978 than the default label, emit a jump to
5979 the default label using condition codes
5980 already lying around. With no right branch,
5981 a branch-greater-than will get us to the default
5984 && cost_table[TREE_INT_CST_LOW (node->high)] < 12)
5987 if (node->left->left || node->left->right
5988 || !tree_int_cst_equal (node->left->low, node->left->high))
5990 if (!node_has_high_bound (node, index_type))
5992 emit_cmp_and_jump_insns (index, expand_expr (node->high,
5995 GT, NULL_RTX, mode, unsignedp, 0,
5999 emit_case_nodes (index, node->left, default_label, index_type);
6002 /* We cannot process node->left normally
6003 since we haven't ruled out the numbers less than
6004 this node's value. So handle node->left explicitly. */
6005 do_jump_if_equal (index,
6006 expand_expr (node->left->low, NULL_RTX,
6008 label_rtx (node->left->code_label), unsignedp);
6013 /* Node is a range. These cases are very similar to those for a single
6014 value, except that we do not start by testing whether this node
6015 is the one to branch to. */
6017 if (node->right != 0 && node->left != 0)
6019 /* Node has subtrees on both sides.
6020 If the right-hand subtree is bounded,
6021 test for it first, since we can go straight there.
6022 Otherwise, we need to make a branch in the control structure,
6023 then handle the two subtrees. */
6024 tree test_label = 0;
6027 if (node_is_bounded (node->right, index_type))
6028 /* Right hand node is fully bounded so we can eliminate any
6029 testing and branch directly to the target code. */
6030 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6032 GT, NULL_RTX, mode, unsignedp, 0,
6033 label_rtx (node->right->code_label));
6036 /* Right hand node requires testing.
6037 Branch to a label where we will handle it later. */
6039 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6040 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6042 GT, NULL_RTX, mode, unsignedp, 0,
6043 label_rtx (test_label));
6046 /* Value belongs to this node or to the left-hand subtree. */
6048 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6050 GE, NULL_RTX, mode, unsignedp, 0,
6051 label_rtx (node->code_label));
6053 /* Handle the left-hand subtree. */
6054 emit_case_nodes (index, node->left, default_label, index_type);
6056 /* If right node had to be handled later, do that now. */
6060 /* If the left-hand subtree fell through,
6061 don't let it fall into the right-hand subtree. */
6062 emit_jump_if_reachable (default_label);
6064 expand_label (test_label);
6065 emit_case_nodes (index, node->right, default_label, index_type);
6069 else if (node->right != 0 && node->left == 0)
6071 /* Deal with values to the left of this node,
6072 if they are possible. */
6073 if (!node_has_low_bound (node, index_type))
6075 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6077 LT, NULL_RTX, mode, unsignedp, 0,
6081 /* Value belongs to this node or to the right-hand subtree. */
6083 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6085 LE, NULL_RTX, mode, unsignedp, 0,
6086 label_rtx (node->code_label));
6088 emit_case_nodes (index, node->right, default_label, index_type);
6091 else if (node->right == 0 && node->left != 0)
6093 /* Deal with values to the right of this node,
6094 if they are possible. */
6095 if (!node_has_high_bound (node, index_type))
6097 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6099 GT, NULL_RTX, mode, unsignedp, 0,
6103 /* Value belongs to this node or to the left-hand subtree. */
6105 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6107 GE, NULL_RTX, mode, unsignedp, 0,
6108 label_rtx (node->code_label));
6110 emit_case_nodes (index, node->left, default_label, index_type);
6115 /* Node has no children so we check low and high bounds to remove
6116 redundant tests. Only one of the bounds can exist,
6117 since otherwise this node is bounded--a case tested already. */
6119 if (!node_has_high_bound (node, index_type))
6121 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6123 GT, NULL_RTX, mode, unsignedp, 0,
6127 if (!node_has_low_bound (node, index_type))
6129 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6131 LT, NULL_RTX, mode, unsignedp, 0,
6135 emit_jump (label_rtx (node->code_label));
6140 /* These routines are used by the loop unrolling code. They copy BLOCK trees
6141 so that the debugging info will be correct for the unrolled loop. */
6143 /* Indexed by block number, contains a pointer to the N'th block node.
6145 Allocated by the call to identify_blocks, then released after the call
6146 to reorder_blocks in the function unroll_block_trees. */
6148 static tree *block_vector;
6151 find_loop_tree_blocks ()
6153 tree block = DECL_INITIAL (current_function_decl);
6155 block_vector = identify_blocks (block, get_insns ());
6159 unroll_block_trees ()
6161 tree block = DECL_INITIAL (current_function_decl);
6163 reorder_blocks (block_vector, block, get_insns ());
6165 /* Release any memory allocated by identify_blocks. */
6167 free (block_vector);