1 /* Expands front end tree to back end RTL for GCC
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
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. */
38 #include "coretypes.h"
47 #include "insn-config.h"
50 #include "hard-reg-set.h"
57 #include "langhooks.h"
63 /* Functions and data structures for expanding case statements. */
65 /* Case label structure, used to hold info on labels within case
66 statements. We handle "range" labels; for a single-value label
67 as in C, the high and low limits are the same.
69 An AVL tree of case nodes is initially created, and later transformed
70 to a list linked via the RIGHT fields in the nodes. Nodes with
71 higher case values are later in the list.
73 Switch statements can be output in one of two forms. A branch table
74 is used if there are more than a few labels and the labels are dense
75 within the range between the smallest and largest case value. If a
76 branch table is used, no further manipulations are done with the case
79 The alternative to the use of a branch table is to generate a series
80 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
81 and PARENT fields to hold a binary tree. Initially the tree is
82 totally unbalanced, with everything on the right. We balance the tree
83 with nodes on the left having lower case values than the parent
84 and nodes on the right having higher values. We then output the tree
87 struct case_node GTY(())
89 struct case_node *left; /* Left son in binary tree */
90 struct case_node *right; /* Right son in binary tree; also node chain */
91 struct case_node *parent; /* Parent of node in binary tree */
92 tree low; /* Lowest index value for this label */
93 tree high; /* Highest index value for this label */
94 tree code_label; /* Label to jump to when node matches */
98 typedef struct case_node case_node;
99 typedef struct case_node *case_node_ptr;
101 /* These are used by estimate_case_costs and balance_case_nodes. */
103 /* This must be a signed type, and non-ANSI compilers lack signed char. */
104 static short cost_table_[129];
105 static int use_cost_table;
106 static int cost_table_initialized;
108 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
110 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
112 /* Stack of control and binding constructs we are currently inside.
114 These constructs begin when you call `expand_start_WHATEVER'
115 and end when you call `expand_end_WHATEVER'. This stack records
116 info about how the construct began that tells the end-function
117 what to do. It also may provide information about the construct
118 to alter the behavior of other constructs within the body.
119 For example, they may affect the behavior of C `break' and `continue'.
121 Each construct gets one `struct nesting' object.
122 All of these objects are chained through the `all' field.
123 `nesting_stack' points to the first object (innermost construct).
124 The position of an entry on `nesting_stack' is in its `depth' field.
126 Each type of construct has its own individual stack.
127 For example, loops have `cond_stack'. Each object points to the
128 next object of the same type through the `next' field.
130 Some constructs are visible to `break' exit-statements and others
131 are not. Which constructs are visible depends on the language.
132 Therefore, the data structure allows each construct to be visible
133 or not, according to the args given when the construct is started.
134 The construct is visible if the `exit_label' field is non-null.
135 In that case, the value should be a CODE_LABEL rtx. */
137 struct nesting GTY(())
140 struct nesting *next;
150 /* For conds (if-then and if-then-else statements). */
153 /* Label for the end of the if construct.
154 There is none if EXITFLAG was not set
155 and no `else' has been seen yet. */
157 /* Label for the end of this alternative.
158 This may be the end of the if or the next else/elseif. */
160 } GTY ((tag ("COND_NESTING"))) cond;
161 /* For variable binding contours. */
164 /* Sequence number of this binding contour within the function,
165 in order of entry. */
166 int block_start_count;
167 /* Nonzero => value to restore stack to on exit. */
169 /* The NOTE that starts this contour.
170 Used by expand_goto to check whether the destination
171 is within each contour or not. */
173 /* Innermost containing binding contour that has a stack level. */
174 struct nesting *innermost_stack_block;
175 /* List of cleanups to be run on exit from this contour.
176 This is a list of expressions to be evaluated.
177 The TREE_PURPOSE of each link is the ..._DECL node
178 which the cleanup pertains to. */
180 /* List of cleanup-lists of blocks containing this block,
181 as they were at the locus where this block appears.
182 There is an element for each containing block,
183 ordered innermost containing block first.
184 The tail of this list can be 0,
185 if all remaining elements would be empty lists.
186 The element's TREE_VALUE is the cleanup-list of that block,
187 which may be null. */
189 /* Chain of labels defined inside this binding contour.
190 For contours that have stack levels or cleanups. */
191 struct label_chain *label_chain;
192 /* Nonzero if this is associated with an EH region. */
193 int exception_region;
194 /* The saved target_temp_slot_level from our outer block.
195 We may reset target_temp_slot_level to be the level of
196 this block, if that is done, target_temp_slot_level
197 reverts to the saved target_temp_slot_level at the very
199 int block_target_temp_slot_level;
200 /* True if we are currently emitting insns in an area of
201 output code that is controlled by a conditional
202 expression. This is used by the cleanup handling code to
203 generate conditional cleanup actions. */
204 int conditional_code;
205 /* A place to move the start of the exception region for any
206 of the conditional cleanups, must be at the end or after
207 the start of the last unconditional cleanup, and before any
208 conditional branch points. */
209 rtx last_unconditional_cleanup;
210 } GTY ((tag ("BLOCK_NESTING"))) block;
211 /* For switch (C) or case (Pascal) statements. */
214 /* The insn after which the case dispatch should finally
215 be emitted. Zero for a dummy. */
217 /* A list of case labels; it is first built as an AVL tree.
218 During expand_end_case, this is converted to a list, and may be
219 rearranged into a nearly balanced binary tree. */
220 struct case_node *case_list;
221 /* Label to jump to if no case matches. */
223 /* The expression to be dispatched on. */
225 /* Type that INDEX_EXPR should be converted to. */
227 /* Name of this kind of statement, for warnings. */
228 const char *printname;
229 /* Used to save no_line_numbers till we see the first case label.
230 We set this to -1 when we see the first case label in this
232 int line_number_status;
233 } GTY ((tag ("CASE_NESTING"))) case_stmt;
234 } GTY ((desc ("%1.desc"))) data;
237 /* Allocate and return a new `struct nesting'. */
239 #define ALLOC_NESTING() ggc_alloc (sizeof (struct nesting))
241 /* Pop the nesting stack element by element until we pop off
242 the element which is at the top of STACK.
243 Update all the other stacks, popping off elements from them
244 as we pop them from nesting_stack. */
246 #define POPSTACK(STACK) \
247 do { struct nesting *target = STACK; \
248 struct nesting *this; \
249 do { this = nesting_stack; \
250 if (cond_stack == this) \
251 cond_stack = cond_stack->next; \
252 if (block_stack == this) \
253 block_stack = block_stack->next; \
254 if (stack_block_stack == this) \
255 stack_block_stack = stack_block_stack->next; \
256 if (case_stack == this) \
257 case_stack = case_stack->next; \
258 nesting_depth = nesting_stack->depth - 1; \
259 nesting_stack = this->all; } \
260 while (this != target); } while (0)
262 /* In some cases it is impossible to generate code for a forward goto
263 until the label definition is seen. This happens when it may be necessary
264 for the goto to reset the stack pointer: we don't yet know how to do that.
265 So expand_goto puts an entry on this fixup list.
266 Each time a binding contour that resets the stack is exited,
268 If the target label has now been defined, we can insert the proper code. */
270 struct goto_fixup GTY(())
272 /* Points to following fixup. */
273 struct goto_fixup *next;
274 /* Points to the insn before the jump insn.
275 If more code must be inserted, it goes after this insn. */
277 /* The LABEL_DECL that this jump is jumping to, or 0
278 for break, continue or return. */
280 /* The BLOCK for the place where this goto was found. */
282 /* The CODE_LABEL rtx that this is jumping to. */
284 /* Number of binding contours started in current function
285 before the label reference. */
286 int block_start_count;
287 /* The outermost stack level that should be restored for this jump.
288 Each time a binding contour that resets the stack is exited,
289 if the target label is *not* yet defined, this slot is updated. */
291 /* List of lists of cleanup expressions to be run by this goto.
292 There is one element for each block that this goto is within.
293 The tail of this list can be 0,
294 if all remaining elements would be empty.
295 The TREE_VALUE contains the cleanup list of that block as of the
296 time this goto was seen.
297 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
298 tree cleanup_list_list;
301 /* Within any binding contour that must restore a stack level,
302 all labels are recorded with a chain of these structures. */
304 struct label_chain GTY(())
306 /* Points to following fixup. */
307 struct label_chain *next;
311 struct stmt_status GTY(())
313 /* Chain of all pending binding contours. */
314 struct nesting * x_block_stack;
316 /* If any new stacks are added here, add them to POPSTACKS too. */
318 /* Chain of all pending binding contours that restore stack levels
320 struct nesting * x_stack_block_stack;
322 /* Chain of all pending conditional statements. */
323 struct nesting * x_cond_stack;
325 /* Chain of all pending case or switch statements. */
326 struct nesting * x_case_stack;
328 /* Separate chain including all of the above,
329 chained through the `all' field. */
330 struct nesting * x_nesting_stack;
332 /* Number of entries on nesting_stack now. */
335 /* Number of binding contours started so far in this function. */
336 int x_block_start_count;
338 /* Each time we expand an expression-statement,
339 record the expr's type and its RTL value here. */
340 tree x_last_expr_type;
341 rtx x_last_expr_value;
342 rtx x_last_expr_alt_rtl;
344 /* Nonzero if within a ({...}) grouping, in which case we must
345 always compute a value for each expr-stmt in case it is the last one. */
346 int x_expr_stmts_for_value;
348 /* Location of last line-number note, whether we actually
349 emitted it or not. */
350 location_t x_emit_locus;
352 struct goto_fixup *x_goto_fixup_chain;
355 #define block_stack (cfun->stmt->x_block_stack)
356 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
357 #define cond_stack (cfun->stmt->x_cond_stack)
358 #define case_stack (cfun->stmt->x_case_stack)
359 #define nesting_stack (cfun->stmt->x_nesting_stack)
360 #define nesting_depth (cfun->stmt->x_nesting_depth)
361 #define current_block_start_count (cfun->stmt->x_block_start_count)
362 #define last_expr_type (cfun->stmt->x_last_expr_type)
363 #define last_expr_value (cfun->stmt->x_last_expr_value)
364 #define last_expr_alt_rtl (cfun->stmt->x_last_expr_alt_rtl)
365 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
366 #define emit_locus (cfun->stmt->x_emit_locus)
367 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
369 /* Nonzero if we are using EH to handle cleanups. */
370 int using_eh_for_cleanups_p = 0;
372 static int n_occurrences (int, const char *);
373 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
374 static void expand_goto_internal (tree, rtx, rtx);
375 static int expand_fixup (tree, rtx, rtx);
376 static void expand_nl_goto_receiver (void);
377 static void fixup_gotos (struct nesting *, rtx, tree, rtx, int);
378 static bool check_operand_nalternatives (tree, tree);
379 static bool check_unique_operand_names (tree, tree);
380 static char *resolve_operand_name_1 (char *, tree, tree);
381 static void expand_null_return_1 (rtx);
382 static enum br_predictor return_prediction (rtx);
383 static rtx shift_return_value (rtx);
384 static void expand_value_return (rtx);
385 static void expand_cleanups (tree, int, int);
386 static void check_seenlabel (void);
387 static void do_jump_if_equal (rtx, rtx, rtx, int);
388 static int estimate_case_costs (case_node_ptr);
389 static bool same_case_target_p (rtx, rtx);
390 static void strip_default_case_nodes (case_node_ptr *, rtx);
391 static bool lshift_cheap_p (void);
392 static int case_bit_test_cmp (const void *, const void *);
393 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
394 static void group_case_nodes (case_node_ptr);
395 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
396 static int node_has_low_bound (case_node_ptr, tree);
397 static int node_has_high_bound (case_node_ptr, tree);
398 static int node_is_bounded (case_node_ptr, tree);
399 static void emit_jump_if_reachable (rtx);
400 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
401 static struct case_node *case_tree2list (case_node *, case_node *);
404 using_eh_for_cleanups (void)
406 using_eh_for_cleanups_p = 1;
410 init_stmt_for_function (void)
412 cfun->stmt = ggc_alloc_cleared (sizeof (struct stmt_status));
415 /* Record the current file and line. Called from emit_line_note. */
418 set_file_and_line_for_stmt (location_t location)
420 /* If we're outputting an inline function, and we add a line note,
421 there may be no CFUN->STMT information. So, there's no need to
424 emit_locus = location;
427 /* Emit a no-op instruction. */
434 last_insn = get_last_insn ();
436 && (GET_CODE (last_insn) == CODE_LABEL
437 || (GET_CODE (last_insn) == NOTE
438 && prev_real_insn (last_insn) == 0)))
439 emit_insn (gen_nop ());
442 /* Return the rtx-label that corresponds to a LABEL_DECL,
443 creating it if necessary. */
446 label_rtx (tree label)
448 if (TREE_CODE (label) != LABEL_DECL)
451 if (!DECL_RTL_SET_P (label))
453 rtx r = gen_label_rtx ();
454 SET_DECL_RTL (label, r);
455 if (FORCED_LABEL (label) || DECL_NONLOCAL (label))
456 LABEL_PRESERVE_P (r) = 1;
459 return DECL_RTL (label);
462 /* As above, but also put it on the forced-reference list of the
463 function that contains it. */
465 force_label_rtx (tree label)
467 rtx ref = label_rtx (label);
468 tree function = decl_function_context (label);
474 if (function != current_function_decl)
475 p = find_function_data (function);
479 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
480 p->expr->x_forced_labels);
484 /* Add an unconditional jump to LABEL as the next sequential instruction. */
487 emit_jump (rtx label)
489 do_pending_stack_adjust ();
490 emit_jump_insn (gen_jump (label));
494 /* Emit code to jump to the address
495 specified by the pointer expression EXP. */
498 expand_computed_goto (tree exp)
500 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
502 x = convert_memory_address (Pmode, x);
505 do_pending_stack_adjust ();
506 emit_indirect_jump (x);
509 /* Handle goto statements and the labels that they can go to. */
511 /* Specify the location in the RTL code of a label LABEL,
512 which is a LABEL_DECL tree node.
514 This is used for the kind of label that the user can jump to with a
515 goto statement, and for alternatives of a switch or case statement.
516 RTL labels generated for loops and conditionals don't go through here;
517 they are generated directly at the RTL level, by other functions below.
519 Note that this has nothing to do with defining label *names*.
520 Languages vary in how they do that and what that even means. */
523 expand_label (tree label)
525 struct label_chain *p;
526 rtx label_r = label_rtx (label);
528 do_pending_stack_adjust ();
529 emit_label (label_r);
530 if (DECL_NAME (label))
531 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
533 if (DECL_NONLOCAL (label))
535 expand_nl_goto_receiver ();
536 nonlocal_goto_handler_labels
537 = gen_rtx_EXPR_LIST (VOIDmode, label_r,
538 nonlocal_goto_handler_labels);
541 if (FORCED_LABEL (label))
542 forced_labels = gen_rtx_EXPR_LIST (VOIDmode, label_r, forced_labels);
544 if (DECL_NONLOCAL (label) || FORCED_LABEL (label))
545 maybe_set_first_label_num (label_r);
547 if (stack_block_stack != 0)
549 p = ggc_alloc (sizeof (struct label_chain));
550 p->next = stack_block_stack->data.block.label_chain;
551 stack_block_stack->data.block.label_chain = p;
556 /* Generate RTL code for a `goto' statement with target label LABEL.
557 LABEL should be a LABEL_DECL tree node that was or will later be
558 defined with `expand_label'. */
561 expand_goto (tree label)
563 #ifdef ENABLE_CHECKING
564 /* Check for a nonlocal goto to a containing function. Should have
565 gotten translated to __builtin_nonlocal_goto. */
566 tree context = decl_function_context (label);
567 if (context != 0 && context != current_function_decl)
571 expand_goto_internal (label, label_rtx (label), NULL_RTX);
574 /* Generate RTL code for a `goto' statement with target label BODY.
575 LABEL should be a LABEL_REF.
576 LAST_INSN, if non-0, is the rtx we should consider as the last
577 insn emitted (for the purposes of cleaning up a return). */
580 expand_goto_internal (tree body, rtx label, rtx last_insn)
582 struct nesting *block;
585 if (GET_CODE (label) != CODE_LABEL)
588 /* If label has already been defined, we can tell now
589 whether and how we must alter the stack level. */
591 if (PREV_INSN (label) != 0)
593 /* Find the innermost pending block that contains the label.
594 (Check containment by comparing insn-uids.)
595 Then restore the outermost stack level within that block,
596 and do cleanups of all blocks contained in it. */
597 for (block = block_stack; block; block = block->next)
599 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
601 if (block->data.block.stack_level != 0)
602 stack_level = block->data.block.stack_level;
603 /* Execute the cleanups for blocks we are exiting. */
604 if (block->data.block.cleanups != 0)
606 expand_cleanups (block->data.block.cleanups, 1, 1);
607 do_pending_stack_adjust ();
613 /* Ensure stack adjust isn't done by emit_jump, as this
614 would clobber the stack pointer. This one should be
615 deleted as dead by flow. */
616 clear_pending_stack_adjust ();
617 do_pending_stack_adjust ();
619 /* Don't do this adjust if it's to the end label and this function
620 is to return with a depressed stack pointer. */
621 if (label == return_label
622 && (((TREE_CODE (TREE_TYPE (current_function_decl))
624 && (TYPE_RETURNS_STACK_DEPRESSED
625 (TREE_TYPE (current_function_decl))))))
628 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
631 if (body != 0 && DECL_TOO_LATE (body))
632 error ("jump to `%s' invalidly jumps into binding contour",
633 IDENTIFIER_POINTER (DECL_NAME (body)));
635 /* Label not yet defined: may need to put this goto
636 on the fixup list. */
637 else if (! expand_fixup (body, label, last_insn))
639 /* No fixup needed. Record that the label is the target
640 of at least one goto that has no fixup. */
642 TREE_ADDRESSABLE (body) = 1;
648 /* Generate if necessary a fixup for a goto
649 whose target label in tree structure (if any) is TREE_LABEL
650 and whose target in rtl is RTL_LABEL.
652 If LAST_INSN is nonzero, we pretend that the jump appears
653 after insn LAST_INSN instead of at the current point in the insn stream.
655 The fixup will be used later to insert insns just before the goto.
656 Those insns will restore the stack level as appropriate for the
657 target label, and will (in the case of C++) also invoke any object
658 destructors which have to be invoked when we exit the scopes which
659 are exited by the goto.
661 Value is nonzero if a fixup is made. */
664 expand_fixup (tree tree_label, rtx rtl_label, rtx last_insn)
666 struct nesting *block, *end_block;
668 /* See if we can recognize which block the label will be output in.
669 This is possible in some very common cases.
670 If we succeed, set END_BLOCK to that block.
671 Otherwise, set it to 0. */
674 && (rtl_label == cond_stack->data.cond.endif_label
675 || rtl_label == cond_stack->data.cond.next_label))
676 end_block = cond_stack;
680 /* Now set END_BLOCK to the binding level to which we will return. */
684 struct nesting *next_block = end_block->all;
687 /* First see if the END_BLOCK is inside the innermost binding level.
688 If so, then no cleanups or stack levels are relevant. */
689 while (next_block && next_block != block)
690 next_block = next_block->all;
695 /* Otherwise, set END_BLOCK to the innermost binding level
696 which is outside the relevant control-structure nesting. */
697 next_block = block_stack->next;
698 for (block = block_stack; block != end_block; block = block->all)
699 if (block == next_block)
700 next_block = next_block->next;
701 end_block = next_block;
704 /* Does any containing block have a stack level or cleanups?
705 If not, no fixup is needed, and that is the normal case
706 (the only case, for standard C). */
707 for (block = block_stack; block != end_block; block = block->next)
708 if (block->data.block.stack_level != 0
709 || block->data.block.cleanups != 0)
712 if (block != end_block)
714 /* Ok, a fixup is needed. Add a fixup to the list of such. */
715 struct goto_fixup *fixup = ggc_alloc (sizeof (struct goto_fixup));
716 /* In case an old stack level is restored, make sure that comes
717 after any pending stack adjust. */
718 /* ?? If the fixup isn't to come at the present position,
719 doing the stack adjust here isn't useful. Doing it with our
720 settings at that location isn't useful either. Let's hope
723 do_pending_stack_adjust ();
724 fixup->target = tree_label;
725 fixup->target_rtl = rtl_label;
727 /* Create a BLOCK node and a corresponding matched set of
728 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
729 this point. The notes will encapsulate any and all fixup
730 code which we might later insert at this point in the insn
731 stream. Also, the BLOCK node will be the parent (i.e. the
732 `SUPERBLOCK') of any other BLOCK nodes which we might create
733 later on when we are expanding the fixup code.
735 Note that optimization passes might move the *_BLOCK notes away,
736 so we use a NOTE_INSN_DELETED as a placeholder. */
739 rtx original_before_jump
740 = last_insn ? last_insn : get_last_insn ();
745 block = make_node (BLOCK);
746 TREE_USED (block) = 1;
749 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
750 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
754 start = emit_note (NOTE_INSN_BLOCK_BEG);
755 NOTE_BLOCK (start) = block;
756 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
757 end = emit_note (NOTE_INSN_BLOCK_END);
758 NOTE_BLOCK (end) = block;
759 fixup->context = block;
761 emit_insn_after (start, original_before_jump);
764 fixup->block_start_count = current_block_start_count;
765 fixup->stack_level = 0;
766 fixup->cleanup_list_list
767 = ((block->data.block.outer_cleanups
768 || block->data.block.cleanups)
769 ? tree_cons (NULL_TREE, block->data.block.cleanups,
770 block->data.block.outer_cleanups)
772 fixup->next = goto_fixup_chain;
773 goto_fixup_chain = fixup;
779 /* Expand any needed fixups in the outputmost binding level of the
780 function. FIRST_INSN is the first insn in the function. */
783 expand_fixups (rtx first_insn)
785 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
788 /* When exiting a binding contour, process all pending gotos requiring fixups.
789 THISBLOCK is the structure that describes the block being exited.
790 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
791 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
792 FIRST_INSN is the insn that began this contour.
794 Gotos that jump out of this contour must restore the
795 stack level and do the cleanups before actually jumping.
797 DONT_JUMP_IN positive means report error if there is a jump into this
798 contour from before the beginning of the contour. This is also done if
799 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
802 fixup_gotos (struct nesting *thisblock, rtx stack_level,
803 tree cleanup_list, rtx first_insn, int dont_jump_in)
805 struct goto_fixup *f, *prev;
807 /* F is the fixup we are considering; PREV is the previous one. */
808 /* We run this loop in two passes so that cleanups of exited blocks
809 are run first, and blocks that are exited are marked so
812 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
814 /* Test for a fixup that is inactive because it is already handled. */
815 if (f->before_jump == 0)
817 /* Delete inactive fixup from the chain, if that is easy to do. */
819 prev->next = f->next;
821 /* Has this fixup's target label been defined?
822 If so, we can finalize it. */
823 else if (PREV_INSN (f->target_rtl) != 0)
827 /* If this fixup jumped into this contour from before the beginning
828 of this contour, report an error. This code used to use
829 the first non-label insn after f->target_rtl, but that's
830 wrong since such can be added, by things like put_var_into_stack
831 and have INSN_UIDs that are out of the range of the block. */
832 /* ??? Bug: this does not detect jumping in through intermediate
833 blocks that have stack levels or cleanups.
834 It detects only a problem with the innermost block
837 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
839 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
840 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
841 && ! DECL_ERROR_ISSUED (f->target))
843 error ("%Jlabel '%D' used before containing binding contour",
844 f->target, f->target);
845 /* Prevent multiple errors for one label. */
846 DECL_ERROR_ISSUED (f->target) = 1;
849 /* We will expand the cleanups into a sequence of their own and
850 then later on we will attach this new sequence to the insn
851 stream just ahead of the actual jump insn. */
855 /* Temporarily restore the lexical context where we will
856 logically be inserting the fixup code. We do this for the
857 sake of getting the debugging information right. */
859 lang_hooks.decls.pushlevel (0);
860 lang_hooks.decls.set_block (f->context);
862 /* Expand the cleanups for blocks this jump exits. */
863 if (f->cleanup_list_list)
866 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
867 /* Marked elements correspond to blocks that have been closed.
868 Do their cleanups. */
869 if (TREE_ADDRESSABLE (lists)
870 && TREE_VALUE (lists) != 0)
872 expand_cleanups (TREE_VALUE (lists), 1, 1);
873 /* Pop any pushes done in the cleanups,
874 in case function is about to return. */
875 do_pending_stack_adjust ();
879 /* Restore stack level for the biggest contour that this
880 jump jumps out of. */
882 && ! (f->target_rtl == return_label
883 && ((TREE_CODE (TREE_TYPE (current_function_decl))
885 && (TYPE_RETURNS_STACK_DEPRESSED
886 (TREE_TYPE (current_function_decl))))))
887 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
889 /* Finish up the sequence containing the insns which implement the
890 necessary cleanups, and then attach that whole sequence to the
891 insn stream just ahead of the actual jump insn. Attaching it
892 at that point insures that any cleanups which are in fact
893 implicit C++ object destructions (which must be executed upon
894 leaving the block) appear (to the debugger) to be taking place
895 in an area of the generated code where the object(s) being
896 destructed are still "in scope". */
898 cleanup_insns = get_insns ();
899 lang_hooks.decls.poplevel (1, 0, 0);
902 emit_insn_after (cleanup_insns, f->before_jump);
908 /* For any still-undefined labels, do the cleanups for this block now.
909 We must do this now since items in the cleanup list may go out
910 of scope when the block ends. */
911 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
912 if (f->before_jump != 0
913 && PREV_INSN (f->target_rtl) == 0
914 /* Label has still not appeared. If we are exiting a block with
915 a stack level to restore, that started before the fixup,
916 mark this stack level as needing restoration
917 when the fixup is later finalized. */
919 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
920 means the label is undefined. That's erroneous, but possible. */
921 && (thisblock->data.block.block_start_count
922 <= f->block_start_count))
924 tree lists = f->cleanup_list_list;
927 for (; lists; lists = TREE_CHAIN (lists))
928 /* If the following elt. corresponds to our containing block
929 then the elt. must be for this block. */
930 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
933 lang_hooks.decls.pushlevel (0);
934 lang_hooks.decls.set_block (f->context);
935 expand_cleanups (TREE_VALUE (lists), 1, 1);
936 do_pending_stack_adjust ();
937 cleanup_insns = get_insns ();
938 lang_hooks.decls.poplevel (1, 0, 0);
940 if (cleanup_insns != 0)
942 = emit_insn_after (cleanup_insns, f->before_jump);
944 f->cleanup_list_list = TREE_CHAIN (lists);
948 f->stack_level = stack_level;
952 /* Return the number of times character C occurs in string S. */
954 n_occurrences (int c, const char *s)
962 /* Generate RTL for an asm statement (explicit assembler code).
963 STRING is a STRING_CST node containing the assembler code text,
964 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
965 insn is volatile; don't optimize it. */
968 expand_asm (tree string, int vol)
972 if (TREE_CODE (string) == ADDR_EXPR)
973 string = TREE_OPERAND (string, 0);
975 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
977 MEM_VOLATILE_P (body) = vol;
984 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
985 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
986 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
987 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
988 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
989 constraint allows the use of a register operand. And, *IS_INOUT
990 will be true if the operand is read-write, i.e., if it is used as
991 an input as well as an output. If *CONSTRAINT_P is not in
992 canonical form, it will be made canonical. (Note that `+' will be
993 replaced with `=' as part of this process.)
995 Returns TRUE if all went well; FALSE if an error occurred. */
998 parse_output_constraint (const char **constraint_p, int operand_num,
999 int ninputs, int noutputs, bool *allows_mem,
1000 bool *allows_reg, bool *is_inout)
1002 const char *constraint = *constraint_p;
1005 /* Assume the constraint doesn't allow the use of either a register
1007 *allows_mem = false;
1008 *allows_reg = false;
1010 /* Allow the `=' or `+' to not be at the beginning of the string,
1011 since it wasn't explicitly documented that way, and there is a
1012 large body of code that puts it last. Swap the character to
1013 the front, so as not to uglify any place else. */
1014 p = strchr (constraint, '=');
1016 p = strchr (constraint, '+');
1018 /* If the string doesn't contain an `=', issue an error
1022 error ("output operand constraint lacks `='");
1026 /* If the constraint begins with `+', then the operand is both read
1027 from and written to. */
1028 *is_inout = (*p == '+');
1030 /* Canonicalize the output constraint so that it begins with `='. */
1031 if (p != constraint || is_inout)
1034 size_t c_len = strlen (constraint);
1036 if (p != constraint)
1037 warning ("output constraint `%c' for operand %d is not at the beginning",
1040 /* Make a copy of the constraint. */
1041 buf = alloca (c_len + 1);
1042 strcpy (buf, constraint);
1043 /* Swap the first character and the `=' or `+'. */
1044 buf[p - constraint] = buf[0];
1045 /* Make sure the first character is an `='. (Until we do this,
1046 it might be a `+'.) */
1048 /* Replace the constraint with the canonicalized string. */
1049 *constraint_p = ggc_alloc_string (buf, c_len);
1050 constraint = *constraint_p;
1053 /* Loop through the constraint string. */
1054 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1059 error ("operand constraint contains incorrectly positioned '+' or '='");
1063 if (operand_num + 1 == ninputs + noutputs)
1065 error ("`%%' constraint used with last operand");
1070 case 'V': case 'm': case 'o':
1074 case '?': case '!': case '*': case '&': case '#':
1075 case 'E': case 'F': case 'G': case 'H':
1076 case 's': case 'i': case 'n':
1077 case 'I': case 'J': case 'K': case 'L': case 'M':
1078 case 'N': case 'O': case 'P': case ',':
1081 case '0': case '1': case '2': case '3': case '4':
1082 case '5': case '6': case '7': case '8': case '9':
1084 error ("matching constraint not valid in output operand");
1088 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1089 excepting those that expand_call created. So match memory
1106 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1108 #ifdef EXTRA_CONSTRAINT_STR
1109 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1111 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1115 /* Otherwise we can't assume anything about the nature of
1116 the constraint except that it isn't purely registers.
1117 Treat it like "g" and hope for the best. */
1128 /* Similar, but for input constraints. */
1131 parse_input_constraint (const char **constraint_p, int input_num,
1132 int ninputs, int noutputs, int ninout,
1133 const char * const * constraints,
1134 bool *allows_mem, bool *allows_reg)
1136 const char *constraint = *constraint_p;
1137 const char *orig_constraint = constraint;
1138 size_t c_len = strlen (constraint);
1140 bool saw_match = false;
1142 /* Assume the constraint doesn't allow the use of either
1143 a register or memory. */
1144 *allows_mem = false;
1145 *allows_reg = false;
1147 /* Make sure constraint has neither `=', `+', nor '&'. */
1149 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1150 switch (constraint[j])
1152 case '+': case '=': case '&':
1153 if (constraint == orig_constraint)
1155 error ("input operand constraint contains `%c'", constraint[j]);
1161 if (constraint == orig_constraint
1162 && input_num + 1 == ninputs - ninout)
1164 error ("`%%' constraint used with last operand");
1169 case 'V': case 'm': case 'o':
1174 case '?': case '!': case '*': case '#':
1175 case 'E': case 'F': case 'G': case 'H':
1176 case 's': case 'i': case 'n':
1177 case 'I': case 'J': case 'K': case 'L': case 'M':
1178 case 'N': case 'O': case 'P': case ',':
1181 /* Whether or not a numeric constraint allows a register is
1182 decided by the matching constraint, and so there is no need
1183 to do anything special with them. We must handle them in
1184 the default case, so that we don't unnecessarily force
1185 operands to memory. */
1186 case '0': case '1': case '2': case '3': case '4':
1187 case '5': case '6': case '7': case '8': case '9':
1190 unsigned long match;
1194 match = strtoul (constraint + j, &end, 10);
1195 if (match >= (unsigned long) noutputs)
1197 error ("matching constraint references invalid operand number");
1201 /* Try and find the real constraint for this dup. Only do this
1202 if the matching constraint is the only alternative. */
1204 && (j == 0 || (j == 1 && constraint[0] == '%')))
1206 constraint = constraints[match];
1207 *constraint_p = constraint;
1208 c_len = strlen (constraint);
1210 /* ??? At the end of the loop, we will skip the first part of
1211 the matched constraint. This assumes not only that the
1212 other constraint is an output constraint, but also that
1213 the '=' or '+' come first. */
1217 j = end - constraint;
1218 /* Anticipate increment at end of loop. */
1233 if (! ISALPHA (constraint[j]))
1235 error ("invalid punctuation `%c' in constraint", constraint[j]);
1238 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1241 #ifdef EXTRA_CONSTRAINT_STR
1242 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1244 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1248 /* Otherwise we can't assume anything about the nature of
1249 the constraint except that it isn't purely registers.
1250 Treat it like "g" and hope for the best. */
1258 if (saw_match && !*allows_reg)
1259 warning ("matching constraint does not allow a register");
1264 /* INPUT is one of the input operands from EXPR, an ASM_EXPR. Returns true
1265 if it is an operand which must be passed in memory (i.e. an "m"
1266 constraint), false otherwise. */
1269 asm_op_is_mem_input (tree input, tree expr)
1271 const char *constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (input)));
1272 tree outputs = ASM_OUTPUTS (expr);
1273 int noutputs = list_length (outputs);
1274 const char **constraints
1275 = (const char **) alloca ((noutputs) * sizeof (const char *));
1277 bool allows_mem, allows_reg;
1280 /* Collect output constraints. */
1281 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1282 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1284 /* We pass 0 for input_num, ninputs and ninout; they are only used for
1285 error checking which will be done at expand time. */
1286 parse_input_constraint (&constraint, 0, 0, noutputs, 0, constraints,
1287 &allows_mem, &allows_reg);
1288 return (!allows_reg && allows_mem);
1291 /* Check for overlap between registers marked in CLOBBERED_REGS and
1292 anything inappropriate in DECL. Emit error and return TRUE for error,
1296 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
1298 /* Conflicts between asm-declared register variables and the clobber
1299 list are not allowed. */
1300 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1301 && DECL_REGISTER (decl)
1302 && REG_P (DECL_RTL (decl))
1303 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1305 rtx reg = DECL_RTL (decl);
1308 for (regno = REGNO (reg);
1309 regno < (REGNO (reg)
1310 + hard_regno_nregs[REGNO (reg)][GET_MODE (reg)]);
1312 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1314 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1315 IDENTIFIER_POINTER (DECL_NAME (decl)));
1317 /* Reset registerness to stop multiple errors emitted for a
1319 DECL_REGISTER (decl) = 0;
1326 /* Generate RTL for an asm statement with arguments.
1327 STRING is the instruction template.
1328 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1329 Each output or input has an expression in the TREE_VALUE and
1330 and a tree list in TREE_PURPOSE which in turn contains a constraint
1331 name in TREE_VALUE (or NULL_TREE) and a constraint string
1333 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1334 that is clobbered by this insn.
1336 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1337 Some elements of OUTPUTS may be replaced with trees representing temporary
1338 values. The caller should copy those temporary values to the originally
1341 VOL nonzero means the insn is volatile; don't optimize it. */
1344 expand_asm_operands (tree string, tree outputs, tree inputs,
1345 tree clobbers, int vol, location_t locus)
1347 rtvec argvec, constraintvec;
1349 int ninputs = list_length (inputs);
1350 int noutputs = list_length (outputs);
1353 HARD_REG_SET clobbered_regs;
1354 int clobber_conflict_found = 0;
1358 /* Vector of RTX's of evaluated output operands. */
1359 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
1360 int *inout_opnum = alloca (noutputs * sizeof (int));
1361 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
1362 enum machine_mode *inout_mode
1363 = alloca (noutputs * sizeof (enum machine_mode));
1364 const char **constraints
1365 = alloca ((noutputs + ninputs) * sizeof (const char *));
1366 int old_generating_concat_p = generating_concat_p;
1368 /* An ASM with no outputs needs to be treated as volatile, for now. */
1372 if (! check_operand_nalternatives (outputs, inputs))
1375 string = resolve_asm_operand_names (string, outputs, inputs);
1377 /* Collect constraints. */
1379 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1380 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1381 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1382 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1384 /* Sometimes we wish to automatically clobber registers across an asm.
1385 Case in point is when the i386 backend moved from cc0 to a hard reg --
1386 maintaining source-level compatibility means automatically clobbering
1387 the flags register. */
1388 clobbers = targetm.md_asm_clobbers (clobbers);
1390 /* Count the number of meaningful clobbered registers, ignoring what
1391 we would ignore later. */
1393 CLEAR_HARD_REG_SET (clobbered_regs);
1394 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1396 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1398 i = decode_reg_name (regname);
1399 if (i >= 0 || i == -4)
1402 error ("unknown register name `%s' in `asm'", regname);
1404 /* Mark clobbered registers. */
1407 /* Clobbering the PIC register is an error */
1408 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1410 error ("PIC register `%s' clobbered in `asm'", regname);
1414 SET_HARD_REG_BIT (clobbered_regs, i);
1420 /* First pass over inputs and outputs checks validity and sets
1421 mark_addressable if needed. */
1424 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1426 tree val = TREE_VALUE (tail);
1427 tree type = TREE_TYPE (val);
1428 const char *constraint;
1433 /* If there's an erroneous arg, emit no insn. */
1434 if (type == error_mark_node)
1437 /* Try to parse the output constraint. If that fails, there's
1438 no point in going further. */
1439 constraint = constraints[i];
1440 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1441 &allows_mem, &allows_reg, &is_inout))
1448 && REG_P (DECL_RTL (val))
1449 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1450 lang_hooks.mark_addressable (val);
1457 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1459 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1463 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1465 bool allows_reg, allows_mem;
1466 const char *constraint;
1468 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1469 would get VOIDmode and that could cause a crash in reload. */
1470 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1473 constraint = constraints[i + noutputs];
1474 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1475 constraints, &allows_mem, &allows_reg))
1478 if (! allows_reg && allows_mem)
1479 lang_hooks.mark_addressable (TREE_VALUE (tail));
1482 /* Second pass evaluates arguments. */
1485 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1487 tree val = TREE_VALUE (tail);
1488 tree type = TREE_TYPE (val);
1494 if (!parse_output_constraint (&constraints[i], i, ninputs,
1495 noutputs, &allows_mem, &allows_reg,
1499 /* If an output operand is not a decl or indirect ref and our constraint
1500 allows a register, make a temporary to act as an intermediate.
1501 Make the asm insn write into that, then our caller will copy it to
1502 the real output operand. Likewise for promoted variables. */
1504 generating_concat_p = 0;
1506 real_output_rtx[i] = NULL_RTX;
1507 if ((TREE_CODE (val) == INDIRECT_REF
1510 && (allows_mem || REG_P (DECL_RTL (val)))
1511 && ! (REG_P (DECL_RTL (val))
1512 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1516 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1517 if (GET_CODE (op) == MEM)
1518 op = validize_mem (op);
1520 if (! allows_reg && GET_CODE (op) != MEM)
1521 error ("output number %d not directly addressable", i);
1522 if ((! allows_mem && GET_CODE (op) == MEM)
1523 || GET_CODE (op) == CONCAT)
1525 real_output_rtx[i] = protect_from_queue (op, 1);
1526 op = gen_reg_rtx (GET_MODE (op));
1528 emit_move_insn (op, real_output_rtx[i]);
1533 op = assign_temp (type, 0, 0, 1);
1534 op = validize_mem (op);
1535 TREE_VALUE (tail) = make_tree (type, op);
1539 generating_concat_p = old_generating_concat_p;
1543 inout_mode[ninout] = TYPE_MODE (type);
1544 inout_opnum[ninout++] = i;
1547 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1548 clobber_conflict_found = 1;
1551 /* Make vectors for the expression-rtx, constraint strings,
1552 and named operands. */
1554 argvec = rtvec_alloc (ninputs);
1555 constraintvec = rtvec_alloc (ninputs);
1557 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1558 : GET_MODE (output_rtx[0])),
1559 TREE_STRING_POINTER (string),
1560 empty_string, 0, argvec, constraintvec,
1563 MEM_VOLATILE_P (body) = vol;
1565 /* Eval the inputs and put them into ARGVEC.
1566 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1568 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1570 bool allows_reg, allows_mem;
1571 const char *constraint;
1575 constraint = constraints[i + noutputs];
1576 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1577 constraints, &allows_mem, &allows_reg))
1580 generating_concat_p = 0;
1582 val = TREE_VALUE (tail);
1583 type = TREE_TYPE (val);
1584 op = expand_expr (val, NULL_RTX, VOIDmode,
1585 (allows_mem && !allows_reg
1586 ? EXPAND_MEMORY : EXPAND_NORMAL));
1588 /* Never pass a CONCAT to an ASM. */
1589 if (GET_CODE (op) == CONCAT)
1590 op = force_reg (GET_MODE (op), op);
1591 else if (GET_CODE (op) == MEM)
1592 op = validize_mem (op);
1594 if (asm_operand_ok (op, constraint) <= 0)
1597 op = force_reg (TYPE_MODE (type), op);
1598 else if (!allows_mem)
1599 warning ("asm operand %d probably doesn't match constraints",
1601 else if (GET_CODE (op) == MEM)
1603 /* We won't recognize either volatile memory or memory
1604 with a queued address as available a memory_operand
1605 at this point. Ignore it: clearly this *is* a memory. */
1609 warning ("use of memory input without lvalue in "
1610 "asm operand %d is deprecated", i + noutputs);
1612 if (CONSTANT_P (op))
1614 rtx mem = force_const_mem (TYPE_MODE (type), op);
1616 op = validize_mem (mem);
1618 op = force_reg (TYPE_MODE (type), op);
1621 || GET_CODE (op) == SUBREG
1622 || GET_CODE (op) == ADDRESSOF
1623 || GET_CODE (op) == CONCAT)
1625 tree qual_type = build_qualified_type (type,
1627 | TYPE_QUAL_CONST));
1628 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1629 memloc = validize_mem (memloc);
1630 emit_move_insn (memloc, op);
1636 generating_concat_p = old_generating_concat_p;
1637 ASM_OPERANDS_INPUT (body, i) = op;
1639 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1640 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1642 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1643 clobber_conflict_found = 1;
1646 /* Protect all the operands from the queue now that they have all been
1649 generating_concat_p = 0;
1651 for (i = 0; i < ninputs - ninout; i++)
1652 ASM_OPERANDS_INPUT (body, i)
1653 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1655 for (i = 0; i < noutputs; i++)
1656 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1658 /* For in-out operands, copy output rtx to input rtx. */
1659 for (i = 0; i < ninout; i++)
1661 int j = inout_opnum[i];
1664 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1667 sprintf (buffer, "%d", j);
1668 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1669 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
1672 generating_concat_p = old_generating_concat_p;
1674 /* Now, for each output, construct an rtx
1675 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1676 ARGVEC CONSTRAINTS OPNAMES))
1677 If there is more than one, put them inside a PARALLEL. */
1679 if (noutputs == 1 && nclobbers == 0)
1681 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1682 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1685 else if (noutputs == 0 && nclobbers == 0)
1687 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1699 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1701 /* For each output operand, store a SET. */
1702 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1704 XVECEXP (body, 0, i)
1705 = gen_rtx_SET (VOIDmode,
1707 gen_rtx_ASM_OPERANDS
1708 (GET_MODE (output_rtx[i]),
1709 TREE_STRING_POINTER (string),
1710 constraints[i], i, argvec, constraintvec,
1713 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1716 /* If there are no outputs (but there are some clobbers)
1717 store the bare ASM_OPERANDS into the PARALLEL. */
1720 XVECEXP (body, 0, i++) = obody;
1722 /* Store (clobber REG) for each clobbered register specified. */
1724 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1726 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1727 int j = decode_reg_name (regname);
1732 if (j == -3) /* `cc', which is not a register */
1735 if (j == -4) /* `memory', don't cache memory across asm */
1737 XVECEXP (body, 0, i++)
1738 = gen_rtx_CLOBBER (VOIDmode,
1741 gen_rtx_SCRATCH (VOIDmode)));
1745 /* Ignore unknown register, error already signaled. */
1749 /* Use QImode since that's guaranteed to clobber just one reg. */
1750 clobbered_reg = gen_rtx_REG (QImode, j);
1752 /* Do sanity check for overlap between clobbers and respectively
1753 input and outputs that hasn't been handled. Such overlap
1754 should have been detected and reported above. */
1755 if (!clobber_conflict_found)
1759 /* We test the old body (obody) contents to avoid tripping
1760 over the under-construction body. */
1761 for (opno = 0; opno < noutputs; opno++)
1762 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1763 internal_error ("asm clobber conflict with output operand");
1765 for (opno = 0; opno < ninputs - ninout; opno++)
1766 if (reg_overlap_mentioned_p (clobbered_reg,
1767 ASM_OPERANDS_INPUT (obody, opno)))
1768 internal_error ("asm clobber conflict with input operand");
1771 XVECEXP (body, 0, i++)
1772 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1778 /* For any outputs that needed reloading into registers, spill them
1779 back to where they belong. */
1780 for (i = 0; i < noutputs; ++i)
1781 if (real_output_rtx[i])
1782 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1788 expand_asm_expr (tree exp)
1794 if (ASM_INPUT_P (exp))
1796 expand_asm (ASM_STRING (exp), ASM_VOLATILE_P (exp));
1800 outputs = ASM_OUTPUTS (exp);
1801 noutputs = list_length (outputs);
1802 /* o[I] is the place that output number I should be written. */
1803 o = (tree *) alloca (noutputs * sizeof (tree));
1805 /* Record the contents of OUTPUTS before it is modified. */
1806 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1807 o[i] = TREE_VALUE (tail);
1809 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
1810 OUTPUTS some trees for where the values were actually stored. */
1811 expand_asm_operands (ASM_STRING (exp), outputs, ASM_INPUTS (exp),
1812 ASM_CLOBBERS (exp), ASM_VOLATILE_P (exp),
1815 /* Copy all the intermediate outputs into the specified outputs. */
1816 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1818 if (o[i] != TREE_VALUE (tail))
1820 expand_assignment (o[i], TREE_VALUE (tail), 0);
1823 /* Restore the original value so that it's correct the next
1824 time we expand this function. */
1825 TREE_VALUE (tail) = o[i];
1829 /* Those MODIFY_EXPRs could do autoincrements. */
1833 /* A subroutine of expand_asm_operands. Check that all operands have
1834 the same number of alternatives. Return true if so. */
1837 check_operand_nalternatives (tree outputs, tree inputs)
1839 if (outputs || inputs)
1841 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1843 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1846 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1848 error ("too many alternatives in `asm'");
1855 const char *constraint
1856 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1858 if (n_occurrences (',', constraint) != nalternatives)
1860 error ("operand constraints for `asm' differ in number of alternatives");
1864 if (TREE_CHAIN (tmp))
1865 tmp = TREE_CHAIN (tmp);
1867 tmp = next, next = 0;
1874 /* A subroutine of expand_asm_operands. Check that all operand names
1875 are unique. Return true if so. We rely on the fact that these names
1876 are identifiers, and so have been canonicalized by get_identifier,
1877 so all we need are pointer comparisons. */
1880 check_unique_operand_names (tree outputs, tree inputs)
1884 for (i = outputs; i ; i = TREE_CHAIN (i))
1886 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1890 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1891 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1895 for (i = inputs; i ; i = TREE_CHAIN (i))
1897 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1901 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1902 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1904 for (j = outputs; j ; j = TREE_CHAIN (j))
1905 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1912 error ("duplicate asm operand name '%s'",
1913 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1917 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1918 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1919 STRING and in the constraints to those numbers. */
1922 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1929 check_unique_operand_names (outputs, inputs);
1931 /* Substitute [<name>] in input constraint strings. There should be no
1932 named operands in output constraints. */
1933 for (t = inputs; t ; t = TREE_CHAIN (t))
1935 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1936 if (strchr (c, '[') != NULL)
1938 p = buffer = xstrdup (c);
1939 while ((p = strchr (p, '[')) != NULL)
1940 p = resolve_operand_name_1 (p, outputs, inputs);
1941 TREE_VALUE (TREE_PURPOSE (t))
1942 = build_string (strlen (buffer), buffer);
1947 /* Now check for any needed substitutions in the template. */
1948 c = TREE_STRING_POINTER (string);
1949 while ((c = strchr (c, '%')) != NULL)
1953 else if (ISALPHA (c[1]) && c[2] == '[')
1964 /* OK, we need to make a copy so we can perform the substitutions.
1965 Assume that we will not need extra space--we get to remove '['
1966 and ']', which means we cannot have a problem until we have more
1967 than 999 operands. */
1968 buffer = xstrdup (TREE_STRING_POINTER (string));
1969 p = buffer + (c - TREE_STRING_POINTER (string));
1971 while ((p = strchr (p, '%')) != NULL)
1975 else if (ISALPHA (p[1]) && p[2] == '[')
1983 p = resolve_operand_name_1 (p, outputs, inputs);
1986 string = build_string (strlen (buffer), buffer);
1993 /* A subroutine of resolve_operand_names. P points to the '[' for a
1994 potential named operand of the form [<name>]. In place, replace
1995 the name and brackets with a number. Return a pointer to the
1996 balance of the string after substitution. */
1999 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
2006 /* Collect the operand name. */
2007 q = strchr (p, ']');
2010 error ("missing close brace for named operand");
2011 return strchr (p, '\0');
2015 /* Resolve the name to a number. */
2016 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2018 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2021 const char *c = TREE_STRING_POINTER (name);
2022 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2026 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2028 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2031 const char *c = TREE_STRING_POINTER (name);
2032 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2038 error ("undefined named operand '%s'", p + 1);
2042 /* Replace the name with the number. Unfortunately, not all libraries
2043 get the return value of sprintf correct, so search for the end of the
2044 generated string by hand. */
2045 sprintf (p, "%d", op);
2046 p = strchr (p, '\0');
2048 /* Verify the no extra buffer space assumption. */
2052 /* Shift the rest of the buffer down to fill the gap. */
2053 memmove (p, q + 1, strlen (q + 1) + 1);
2058 /* Generate RTL to evaluate the expression EXP
2059 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2060 Provided just for backward-compatibility. expand_expr_stmt_value()
2061 should be used for new code. */
2064 expand_expr_stmt (tree exp)
2066 expand_expr_stmt_value (exp, -1, 1);
2069 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2070 whether to (1) save the value of the expression, (0) discard it or
2071 (-1) use expr_stmts_for_value to tell. The use of -1 is
2072 deprecated, and retained only for backward compatibility. */
2075 expand_expr_stmt_value (tree exp, int want_value, int maybe_last)
2081 if (want_value == -1)
2082 want_value = expr_stmts_for_value != 0;
2084 /* If -Wextra, warn about statements with no side effects,
2085 except for an explicit cast to void (e.g. for assert()), and
2086 except for last statement in ({...}) where they may be useful. */
2088 && (expr_stmts_for_value == 0 || ! maybe_last)
2089 && exp != error_mark_node
2090 && warn_unused_value)
2092 if (TREE_SIDE_EFFECTS (exp))
2093 warn_if_unused_value (exp, emit_locus);
2094 else if (!VOID_TYPE_P (TREE_TYPE (exp)) && !TREE_NO_WARNING (exp))
2095 warning ("%Hstatement with no effect", &emit_locus);
2098 /* If EXP is of function type and we are expanding statements for
2099 value, convert it to pointer-to-function. */
2100 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2101 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2103 /* The call to `expand_expr' could cause last_expr_type and
2104 last_expr_value to get reset. Therefore, we set last_expr_value
2105 and last_expr_type *after* calling expand_expr. */
2106 value = expand_expr_real (exp, want_value ? NULL_RTX : const0_rtx,
2107 VOIDmode, 0, &alt_rtl);
2108 type = TREE_TYPE (exp);
2110 /* If all we do is reference a volatile value in memory,
2111 copy it to a register to be sure it is actually touched. */
2112 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2114 if (TYPE_MODE (type) == VOIDmode)
2116 else if (TYPE_MODE (type) != BLKmode)
2117 value = copy_to_reg (value);
2120 rtx lab = gen_label_rtx ();
2122 /* Compare the value with itself to reference it. */
2123 emit_cmp_and_jump_insns (value, value, EQ,
2124 expand_expr (TYPE_SIZE (type),
2125 NULL_RTX, VOIDmode, 0),
2131 /* If this expression is part of a ({...}) and is in memory, we may have
2132 to preserve temporaries. */
2133 preserve_temp_slots (value);
2135 /* Free any temporaries used to evaluate this expression. Any temporary
2136 used as a result of this expression will already have been preserved
2142 last_expr_value = value;
2143 last_expr_alt_rtl = alt_rtl;
2144 last_expr_type = type;
2150 /* Warn if EXP contains any computations whose results are not used.
2151 Return 1 if a warning is printed; 0 otherwise. LOCUS is the
2152 (potential) location of the expression. */
2155 warn_if_unused_value (tree exp, location_t locus)
2158 if (TREE_USED (exp))
2161 /* Don't warn about void constructs. This includes casting to void,
2162 void function calls, and statement expressions with a final cast
2164 if (VOID_TYPE_P (TREE_TYPE (exp)))
2167 if (EXPR_LOCUS (exp))
2168 locus = *EXPR_LOCUS (exp);
2170 switch (TREE_CODE (exp))
2172 case PREINCREMENT_EXPR:
2173 case POSTINCREMENT_EXPR:
2174 case PREDECREMENT_EXPR:
2175 case POSTDECREMENT_EXPR:
2181 case TRY_CATCH_EXPR:
2182 case WITH_CLEANUP_EXPR:
2187 /* For a binding, warn if no side effect within it. */
2188 exp = BIND_EXPR_BODY (exp);
2192 exp = TREE_OPERAND (exp, 0);
2195 case TRUTH_ORIF_EXPR:
2196 case TRUTH_ANDIF_EXPR:
2197 /* In && or ||, warn if 2nd operand has no side effect. */
2198 exp = TREE_OPERAND (exp, 1);
2202 if (TREE_NO_WARNING (exp))
2204 if (warn_if_unused_value (TREE_OPERAND (exp, 0), locus))
2206 /* Let people do `(foo (), 0)' without a warning. */
2207 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2209 exp = TREE_OPERAND (exp, 1);
2214 case NON_LVALUE_EXPR:
2215 /* Don't warn about conversions not explicit in the user's program. */
2216 if (TREE_NO_WARNING (exp))
2218 /* Assignment to a cast usually results in a cast of a modify.
2219 Don't complain about that. There can be an arbitrary number of
2220 casts before the modify, so we must loop until we find the first
2221 non-cast expression and then test to see if that is a modify. */
2223 tree tem = TREE_OPERAND (exp, 0);
2225 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2226 tem = TREE_OPERAND (tem, 0);
2228 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2229 || TREE_CODE (tem) == CALL_EXPR)
2235 /* Don't warn about automatic dereferencing of references, since
2236 the user cannot control it. */
2237 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2239 exp = TREE_OPERAND (exp, 0);
2245 /* Referencing a volatile value is a side effect, so don't warn. */
2247 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2248 && TREE_THIS_VOLATILE (exp))
2251 /* If this is an expression which has no operands, there is no value
2252 to be unused. There are no such language-independent codes,
2253 but front ends may define such. */
2254 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2255 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2259 /* If this is an expression with side effects, don't warn. */
2260 if (TREE_SIDE_EFFECTS (exp))
2263 warning ("%Hvalue computed is not used", &locus);
2268 /* Clear out the memory of the last expression evaluated. */
2271 clear_last_expr (void)
2273 last_expr_type = NULL_TREE;
2274 last_expr_value = NULL_RTX;
2275 last_expr_alt_rtl = NULL_RTX;
2278 /* Begin a statement-expression, i.e., a series of statements which
2279 may return a value. Return the RTL_EXPR for this statement expr.
2280 The caller must save that value and pass it to
2281 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2282 in the statement-expression are deallocated at the end of the
2286 expand_start_stmt_expr (int has_scope)
2290 /* Make the RTL_EXPR node temporary, not momentary,
2291 so that rtl_expr_chain doesn't become garbage. */
2292 t = make_node (RTL_EXPR);
2293 do_pending_stack_adjust ();
2295 start_sequence_for_rtl_expr (t);
2299 expr_stmts_for_value++;
2303 /* Restore the previous state at the end of a statement that returns a value.
2304 Returns a tree node representing the statement's value and the
2305 insns to compute the value.
2307 The nodes of that expression have been freed by now, so we cannot use them.
2308 But we don't want to do that anyway; the expression has already been
2309 evaluated and now we just want to use the value. So generate a RTL_EXPR
2310 with the proper type and RTL value.
2312 If the last substatement was not an expression,
2313 return something with type `void'. */
2316 expand_end_stmt_expr (tree t)
2320 if (! last_expr_value || ! last_expr_type)
2322 last_expr_value = const0_rtx;
2323 last_expr_alt_rtl = NULL_RTX;
2324 last_expr_type = void_type_node;
2326 else if (!REG_P (last_expr_value) && ! CONSTANT_P (last_expr_value))
2327 /* Remove any possible QUEUED. */
2328 last_expr_value = protect_from_queue (last_expr_value, 0);
2332 TREE_TYPE (t) = last_expr_type;
2333 RTL_EXPR_RTL (t) = last_expr_value;
2334 RTL_EXPR_ALT_RTL (t) = last_expr_alt_rtl;
2335 RTL_EXPR_SEQUENCE (t) = get_insns ();
2337 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2341 /* Don't consider deleting this expr or containing exprs at tree level. */
2342 TREE_SIDE_EFFECTS (t) = 1;
2343 /* Propagate volatility of the actual RTL expr. */
2344 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2347 expr_stmts_for_value--;
2352 /* Generate RTL for the start of an if-then. COND is the expression
2353 whose truth should be tested.
2355 If EXITFLAG is nonzero, this conditional is visible to
2356 `exit_something'. */
2359 expand_start_cond (tree cond, int exitflag)
2361 struct nesting *thiscond = ALLOC_NESTING ();
2363 /* Make an entry on cond_stack for the cond we are entering. */
2365 thiscond->desc = COND_NESTING;
2366 thiscond->next = cond_stack;
2367 thiscond->all = nesting_stack;
2368 thiscond->depth = ++nesting_depth;
2369 thiscond->data.cond.next_label = gen_label_rtx ();
2370 /* Before we encounter an `else', we don't need a separate exit label
2371 unless there are supposed to be exit statements
2372 to exit this conditional. */
2373 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2374 thiscond->data.cond.endif_label = thiscond->exit_label;
2375 cond_stack = thiscond;
2376 nesting_stack = thiscond;
2378 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2381 /* Generate RTL between then-clause and the elseif-clause
2382 of an if-then-elseif-.... */
2385 expand_start_elseif (tree cond)
2387 if (cond_stack->data.cond.endif_label == 0)
2388 cond_stack->data.cond.endif_label = gen_label_rtx ();
2389 emit_jump (cond_stack->data.cond.endif_label);
2390 emit_label (cond_stack->data.cond.next_label);
2391 cond_stack->data.cond.next_label = gen_label_rtx ();
2392 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2395 /* Generate RTL between the then-clause and the else-clause
2396 of an if-then-else. */
2399 expand_start_else (void)
2401 if (cond_stack->data.cond.endif_label == 0)
2402 cond_stack->data.cond.endif_label = gen_label_rtx ();
2404 emit_jump (cond_stack->data.cond.endif_label);
2405 emit_label (cond_stack->data.cond.next_label);
2406 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2409 /* After calling expand_start_else, turn this "else" into an "else if"
2410 by providing another condition. */
2413 expand_elseif (tree cond)
2415 cond_stack->data.cond.next_label = gen_label_rtx ();
2416 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2419 /* Generate RTL for the end of an if-then.
2420 Pop the record for it off of cond_stack. */
2423 expand_end_cond (void)
2425 struct nesting *thiscond = cond_stack;
2427 do_pending_stack_adjust ();
2428 if (thiscond->data.cond.next_label)
2429 emit_label (thiscond->data.cond.next_label);
2430 if (thiscond->data.cond.endif_label)
2431 emit_label (thiscond->data.cond.endif_label);
2433 POPSTACK (cond_stack);
2437 /* Return nonzero if we should preserve sub-expressions as separate
2438 pseudos. We never do so if we aren't optimizing. We always do so
2439 if -fexpensive-optimizations. */
2442 preserve_subexpressions_p (void)
2444 if (flag_expensive_optimizations)
2447 if (optimize == 0 || cfun == 0 || cfun->stmt == 0)
2454 /* Generate RTL to return from the current function, with no value.
2455 (That is, we do not do anything about returning any value.) */
2458 expand_null_return (void)
2462 last_insn = get_last_insn ();
2464 /* If this function was declared to return a value, but we
2465 didn't, clobber the return registers so that they are not
2466 propagated live to the rest of the function. */
2467 clobber_return_register ();
2469 expand_null_return_1 (last_insn);
2472 /* Generate RTL to return directly from the current function.
2473 (That is, we bypass any return value.) */
2476 expand_naked_return (void)
2478 rtx last_insn, end_label;
2480 last_insn = get_last_insn ();
2481 end_label = naked_return_label;
2483 clear_pending_stack_adjust ();
2484 do_pending_stack_adjust ();
2488 end_label = naked_return_label = gen_label_rtx ();
2489 expand_goto_internal (NULL_TREE, end_label, last_insn);
2492 /* Try to guess whether the value of return means error code. */
2493 static enum br_predictor
2494 return_prediction (rtx val)
2496 /* Different heuristics for pointers and scalars. */
2497 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2499 /* NULL is usually not returned. */
2500 if (val == const0_rtx)
2501 return PRED_NULL_RETURN;
2505 /* Negative return values are often used to indicate
2507 if (GET_CODE (val) == CONST_INT
2508 && INTVAL (val) < 0)
2509 return PRED_NEGATIVE_RETURN;
2510 /* Constant return values are also usually erors,
2511 zero/one often mean booleans so exclude them from the
2513 if (CONSTANT_P (val)
2514 && (val != const0_rtx && val != const1_rtx))
2515 return PRED_CONST_RETURN;
2517 return PRED_NO_PREDICTION;
2521 /* If the current function returns values in the most significant part
2522 of a register, shift return value VAL appropriately. The mode of
2523 the function's return type is known not to be BLKmode. */
2526 shift_return_value (rtx val)
2530 type = TREE_TYPE (DECL_RESULT (current_function_decl));
2531 if (targetm.calls.return_in_msb (type))
2534 HOST_WIDE_INT shift;
2536 target = DECL_RTL (DECL_RESULT (current_function_decl));
2537 shift = (GET_MODE_BITSIZE (GET_MODE (target))
2538 - BITS_PER_UNIT * int_size_in_bytes (type));
2540 val = expand_binop (GET_MODE (target), ashl_optab,
2541 gen_lowpart (GET_MODE (target), val),
2542 GEN_INT (shift), target, 1, OPTAB_WIDEN);
2548 /* Generate RTL to return from the current function, with value VAL. */
2551 expand_value_return (rtx val)
2555 enum br_predictor pred;
2557 if (flag_guess_branch_prob
2558 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2560 /* Emit information for branch prediction. */
2563 note = emit_note (NOTE_INSN_PREDICTION);
2565 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2569 last_insn = get_last_insn ();
2570 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2572 /* Copy the value to the return location
2573 unless it's already there. */
2575 if (return_reg != val)
2577 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2578 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
2580 int unsignedp = TYPE_UNSIGNED (type);
2581 enum machine_mode old_mode
2582 = DECL_MODE (DECL_RESULT (current_function_decl));
2583 enum machine_mode mode
2584 = promote_mode (type, old_mode, &unsignedp, 1);
2586 if (mode != old_mode)
2587 val = convert_modes (mode, old_mode, val, unsignedp);
2589 if (GET_CODE (return_reg) == PARALLEL)
2590 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
2592 emit_move_insn (return_reg, val);
2595 expand_null_return_1 (last_insn);
2598 /* Output a return with no value. If LAST_INSN is nonzero,
2599 pretend that the return takes place after LAST_INSN. */
2602 expand_null_return_1 (rtx last_insn)
2604 rtx end_label = cleanup_label ? cleanup_label : return_label;
2606 clear_pending_stack_adjust ();
2607 do_pending_stack_adjust ();
2611 end_label = return_label = gen_label_rtx ();
2612 expand_goto_internal (NULL_TREE, end_label, last_insn);
2615 /* Generate RTL to evaluate the expression RETVAL and return it
2616 from the current function. */
2619 expand_return (tree retval)
2621 /* If there are any cleanups to be performed, then they will
2622 be inserted following LAST_INSN. It is desirable
2623 that the last_insn, for such purposes, should be the
2624 last insn before computing the return value. Otherwise, cleanups
2625 which call functions can clobber the return value. */
2626 /* ??? rms: I think that is erroneous, because in C++ it would
2627 run destructors on variables that might be used in the subsequent
2628 computation of the return value. */
2634 /* If function wants no value, give it none. */
2635 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2637 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2639 expand_null_return ();
2643 if (retval == error_mark_node)
2645 /* Treat this like a return of no value from a function that
2647 expand_null_return ();
2650 else if (TREE_CODE (retval) == RESULT_DECL)
2651 retval_rhs = retval;
2652 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2653 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2654 retval_rhs = TREE_OPERAND (retval, 1);
2656 retval_rhs = retval;
2658 last_insn = get_last_insn ();
2660 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
2662 /* If the result is an aggregate that is being returned in one (or more)
2663 registers, load the registers here. The compiler currently can't handle
2664 copying a BLKmode value into registers. We could put this code in a
2665 more general area (for use by everyone instead of just function
2666 call/return), but until this feature is generally usable it is kept here
2667 (and in expand_call). The value must go into a pseudo in case there
2668 are cleanups that will clobber the real return register. */
2671 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
2672 && REG_P (result_rtl))
2675 unsigned HOST_WIDE_INT bitpos, xbitpos;
2676 unsigned HOST_WIDE_INT padding_correction = 0;
2677 unsigned HOST_WIDE_INT bytes
2678 = int_size_in_bytes (TREE_TYPE (retval_rhs));
2679 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2680 unsigned int bitsize
2681 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
2682 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
2683 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
2684 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2685 enum machine_mode tmpmode, result_reg_mode;
2689 expand_null_return ();
2693 /* If the structure doesn't take up a whole number of words, see
2694 whether the register value should be padded on the left or on
2695 the right. Set PADDING_CORRECTION to the number of padding
2696 bits needed on the left side.
2698 In most ABIs, the structure will be returned at the least end of
2699 the register, which translates to right padding on little-endian
2700 targets and left padding on big-endian targets. The opposite
2701 holds if the structure is returned at the most significant
2702 end of the register. */
2703 if (bytes % UNITS_PER_WORD != 0
2704 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs))
2706 : BYTES_BIG_ENDIAN))
2707 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
2710 /* Copy the structure BITSIZE bits at a time. */
2711 for (bitpos = 0, xbitpos = padding_correction;
2712 bitpos < bytes * BITS_PER_UNIT;
2713 bitpos += bitsize, xbitpos += bitsize)
2715 /* We need a new destination pseudo each time xbitpos is
2716 on a word boundary and when xbitpos == padding_correction
2717 (the first time through). */
2718 if (xbitpos % BITS_PER_WORD == 0
2719 || xbitpos == padding_correction)
2721 /* Generate an appropriate register. */
2722 dst = gen_reg_rtx (word_mode);
2723 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
2725 /* Clear the destination before we move anything into it. */
2726 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
2729 /* We need a new source operand each time bitpos is on a word
2731 if (bitpos % BITS_PER_WORD == 0)
2732 src = operand_subword_force (result_val,
2733 bitpos / BITS_PER_WORD,
2736 /* Use bitpos for the source extraction (left justified) and
2737 xbitpos for the destination store (right justified). */
2738 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
2739 extract_bit_field (src, bitsize,
2740 bitpos % BITS_PER_WORD, 1,
2741 NULL_RTX, word_mode, word_mode,
2746 tmpmode = GET_MODE (result_rtl);
2747 if (tmpmode == BLKmode)
2749 /* Find the smallest integer mode large enough to hold the
2750 entire structure and use that mode instead of BLKmode
2751 on the USE insn for the return register. */
2752 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
2753 tmpmode != VOIDmode;
2754 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
2755 /* Have we found a large enough mode? */
2756 if (GET_MODE_SIZE (tmpmode) >= bytes)
2759 /* No suitable mode found. */
2760 if (tmpmode == VOIDmode)
2763 PUT_MODE (result_rtl, tmpmode);
2766 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
2767 result_reg_mode = word_mode;
2769 result_reg_mode = tmpmode;
2770 result_reg = gen_reg_rtx (result_reg_mode);
2773 for (i = 0; i < n_regs; i++)
2774 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
2777 if (tmpmode != result_reg_mode)
2778 result_reg = gen_lowpart (tmpmode, result_reg);
2780 expand_value_return (result_reg);
2782 else if (retval_rhs != 0
2783 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
2784 && (REG_P (result_rtl)
2785 || (GET_CODE (result_rtl) == PARALLEL)))
2787 /* Calculate the return value into a temporary (usually a pseudo
2789 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
2790 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
2792 val = assign_temp (nt, 0, 0, 1);
2793 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
2794 val = force_not_mem (val);
2796 /* Return the calculated value, doing cleanups first. */
2797 expand_value_return (shift_return_value (val));
2801 /* No cleanups or no hard reg used;
2802 calculate value into hard return reg. */
2803 expand_expr (retval, const0_rtx, VOIDmode, 0);
2805 expand_value_return (result_rtl);
2809 /* Generate the RTL code for entering a binding contour.
2810 The variables are declared one by one, by calls to `expand_decl'.
2812 FLAGS is a bitwise or of the following flags:
2814 1 - Nonzero if this construct should be visible to
2817 2 - Nonzero if this contour does not require a
2818 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
2819 language-independent code should set this flag because they
2820 will not create corresponding BLOCK nodes. (There should be
2821 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
2822 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
2823 when expand_end_bindings is called.
2825 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
2826 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
2830 expand_start_bindings_and_block (int flags, tree block)
2832 struct nesting *thisblock = ALLOC_NESTING ();
2834 int exit_flag = ((flags & 1) != 0);
2835 int block_flag = ((flags & 2) == 0);
2837 /* If a BLOCK is supplied, then the caller should be requesting a
2838 NOTE_INSN_BLOCK_BEG note. */
2839 if (!block_flag && block)
2842 /* Create a note to mark the beginning of the block. */
2843 if (block_flag && !cfun->dont_emit_block_notes)
2845 note = emit_note (NOTE_INSN_BLOCK_BEG);
2846 NOTE_BLOCK (note) = block;
2849 note = emit_note (NOTE_INSN_DELETED);
2851 /* Make an entry on block_stack for the block we are entering. */
2853 thisblock->desc = BLOCK_NESTING;
2854 thisblock->next = block_stack;
2855 thisblock->all = nesting_stack;
2856 thisblock->depth = ++nesting_depth;
2857 thisblock->data.block.stack_level = 0;
2858 thisblock->data.block.cleanups = 0;
2859 thisblock->data.block.exception_region = 0;
2860 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
2862 thisblock->data.block.conditional_code = 0;
2863 thisblock->data.block.last_unconditional_cleanup = note;
2864 /* When we insert instructions after the last unconditional cleanup,
2865 we don't adjust last_insn. That means that a later add_insn will
2866 clobber the instructions we've just added. The easiest way to
2867 fix this is to just insert another instruction here, so that the
2868 instructions inserted after the last unconditional cleanup are
2869 never the last instruction. */
2870 emit_note (NOTE_INSN_DELETED);
2873 && !(block_stack->data.block.cleanups == NULL_TREE
2874 && block_stack->data.block.outer_cleanups == NULL_TREE))
2875 thisblock->data.block.outer_cleanups
2876 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2877 block_stack->data.block.outer_cleanups);
2879 thisblock->data.block.outer_cleanups = 0;
2880 thisblock->data.block.label_chain = 0;
2881 thisblock->data.block.innermost_stack_block = stack_block_stack;
2882 thisblock->data.block.first_insn = note;
2883 thisblock->data.block.block_start_count = ++current_block_start_count;
2884 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
2885 block_stack = thisblock;
2886 nesting_stack = thisblock;
2888 /* Make a new level for allocating stack slots. */
2892 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
2893 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
2894 expand_expr are made. After we end the region, we know that all
2895 space for all temporaries that were created by TARGET_EXPRs will be
2896 destroyed and their space freed for reuse. */
2899 expand_start_target_temps (void)
2901 /* This is so that even if the result is preserved, the space
2902 allocated will be freed, as we know that it is no longer in use. */
2905 /* Start a new binding layer that will keep track of all cleanup
2906 actions to be performed. */
2907 expand_start_bindings (2);
2909 target_temp_slot_level = temp_slot_level;
2913 expand_end_target_temps (void)
2915 expand_end_bindings (NULL_TREE, 0, 0);
2917 /* This is so that even if the result is preserved, the space
2918 allocated will be freed, as we know that it is no longer in use. */
2922 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
2923 in question represents the outermost pair of curly braces (i.e. the "body
2924 block") of a function or method.
2926 For any BLOCK node representing a "body block" of a function or method, the
2927 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
2928 represents the outermost (function) scope for the function or method (i.e.
2929 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
2930 *that* node in turn will point to the relevant FUNCTION_DECL node. */
2933 is_body_block (tree stmt)
2935 if (lang_hooks.no_body_blocks)
2938 if (TREE_CODE (stmt) == BLOCK)
2940 tree parent = BLOCK_SUPERCONTEXT (stmt);
2942 if (parent && TREE_CODE (parent) == BLOCK)
2944 tree grandparent = BLOCK_SUPERCONTEXT (parent);
2946 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
2954 /* True if we are currently emitting insns in an area of output code
2955 that is controlled by a conditional expression. This is used by
2956 the cleanup handling code to generate conditional cleanup actions. */
2959 conditional_context (void)
2961 return block_stack && block_stack->data.block.conditional_code;
2964 /* Return an opaque pointer to the current nesting level, so frontend code
2965 can check its own sanity. */
2968 current_nesting_level (void)
2970 return cfun ? block_stack : 0;
2973 /* Emit code to restore vital registers at the beginning of a nonlocal goto
2976 expand_nl_goto_receiver (void)
2978 /* Clobber the FP when we get here, so we have to make sure it's
2979 marked as used by this function. */
2980 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
2982 /* Mark the static chain as clobbered here so life information
2983 doesn't get messed up for it. */
2984 emit_insn (gen_rtx_CLOBBER (VOIDmode, static_chain_rtx));
2986 #ifdef HAVE_nonlocal_goto
2987 if (! HAVE_nonlocal_goto)
2989 /* First adjust our frame pointer to its actual value. It was
2990 previously set to the start of the virtual area corresponding to
2991 the stacked variables when we branched here and now needs to be
2992 adjusted to the actual hardware fp value.
2994 Assignments are to virtual registers are converted by
2995 instantiate_virtual_regs into the corresponding assignment
2996 to the underlying register (fp in this case) that makes
2997 the original assignment true.
2998 So the following insn will actually be
2999 decrementing fp by STARTING_FRAME_OFFSET. */
3000 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3002 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3003 if (fixed_regs[ARG_POINTER_REGNUM])
3005 #ifdef ELIMINABLE_REGS
3006 /* If the argument pointer can be eliminated in favor of the
3007 frame pointer, we don't need to restore it. We assume here
3008 that if such an elimination is present, it can always be used.
3009 This is the case on all known machines; if we don't make this
3010 assumption, we do unnecessary saving on many machines. */
3011 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3014 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3015 if (elim_regs[i].from == ARG_POINTER_REGNUM
3016 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3019 if (i == ARRAY_SIZE (elim_regs))
3022 /* Now restore our arg pointer from the address at which it
3023 was saved in our stack frame. */
3024 emit_move_insn (virtual_incoming_args_rtx,
3025 copy_to_reg (get_arg_pointer_save_area (cfun)));
3030 #ifdef HAVE_nonlocal_goto_receiver
3031 if (HAVE_nonlocal_goto_receiver)
3032 emit_insn (gen_nonlocal_goto_receiver ());
3035 /* @@@ This is a kludge. Not all machine descriptions define a blockage
3036 insn, but we must not allow the code we just generated to be reordered
3037 by scheduling. Specifically, the update of the frame pointer must
3038 happen immediately, not later. So emit an ASM_INPUT to act as blockage
3040 emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
3043 /* Warn about any unused VARS (which may contain nodes other than
3044 VAR_DECLs, but such nodes are ignored). The nodes are connected
3045 via the TREE_CHAIN field. */
3048 warn_about_unused_variables (tree vars)
3052 if (warn_unused_variable)
3053 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3054 if (TREE_CODE (decl) == VAR_DECL
3055 && ! TREE_USED (decl)
3056 && ! DECL_IN_SYSTEM_HEADER (decl)
3057 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3058 warning ("%Junused variable '%D'", decl, decl);
3061 /* Generate RTL code to terminate a binding contour.
3063 VARS is the chain of VAR_DECL nodes for the variables bound in this
3064 contour. There may actually be other nodes in this chain, but any
3065 nodes other than VAR_DECLS are ignored.
3067 MARK_ENDS is nonzero if we should put a note at the beginning
3068 and end of this binding contour.
3070 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3071 zero if we can jump into this contour only if it does not have a saved
3072 stack level, and negative if we are not to check for invalid use of
3073 labels (because the front end does that). */
3076 expand_end_bindings (tree vars, int mark_ends, int dont_jump_in)
3078 struct nesting *thisblock = block_stack;
3080 /* If any of the variables in this scope were not used, warn the
3082 warn_about_unused_variables (vars);
3084 if (thisblock->exit_label)
3086 do_pending_stack_adjust ();
3087 emit_label (thisblock->exit_label);
3090 /* Don't allow jumping into a block that has a stack level.
3091 Cleanups are allowed, though. */
3092 if (dont_jump_in > 0
3093 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3095 struct label_chain *chain;
3097 /* Any labels in this block are no longer valid to go to.
3098 Mark them to cause an error message. */
3099 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3101 DECL_TOO_LATE (chain->label) = 1;
3102 /* If any goto without a fixup came to this label,
3103 that must be an error, because gotos without fixups
3104 come from outside all saved stack-levels. */
3105 if (TREE_ADDRESSABLE (chain->label))
3106 error ("%Jlabel '%D' used before containing binding contour",
3107 chain->label, chain->label);
3111 /* Restore stack level in effect before the block
3112 (only if variable-size objects allocated). */
3113 /* Perform any cleanups associated with the block. */
3115 if (thisblock->data.block.stack_level != 0
3116 || thisblock->data.block.cleanups != 0)
3121 /* Don't let cleanups affect ({...}) constructs. */
3122 int old_expr_stmts_for_value = expr_stmts_for_value;
3123 rtx old_last_expr_value = last_expr_value;
3124 rtx old_last_expr_alt_rtl = last_expr_alt_rtl;
3125 tree old_last_expr_type = last_expr_type;
3126 expr_stmts_for_value = 0;
3128 /* Only clean up here if this point can actually be reached. */
3129 insn = get_last_insn ();
3130 if (GET_CODE (insn) == NOTE)
3131 insn = prev_nonnote_insn (insn);
3132 reachable = (! insn || GET_CODE (insn) != BARRIER);
3134 /* Do the cleanups. */
3135 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3137 do_pending_stack_adjust ();
3139 expr_stmts_for_value = old_expr_stmts_for_value;
3140 last_expr_value = old_last_expr_value;
3141 last_expr_alt_rtl = old_last_expr_alt_rtl;
3142 last_expr_type = old_last_expr_type;
3144 /* Restore the stack level. */
3146 if (reachable && thisblock->data.block.stack_level != 0)
3148 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3149 thisblock->data.block.stack_level, NULL_RTX);
3150 if (cfun->nonlocal_goto_save_area)
3151 update_nonlocal_goto_save_area ();
3154 /* Any gotos out of this block must also do these things.
3155 Also report any gotos with fixups that came to labels in this
3157 fixup_gotos (thisblock,
3158 thisblock->data.block.stack_level,
3159 thisblock->data.block.cleanups,
3160 thisblock->data.block.first_insn,
3164 /* Mark the beginning and end of the scope if requested.
3165 We do this now, after running cleanups on the variables
3166 just going out of scope, so they are in scope for their cleanups. */
3168 if (mark_ends && !cfun->dont_emit_block_notes)
3170 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3171 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3174 /* Get rid of the beginning-mark if we don't make an end-mark. */
3175 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3177 /* Restore the temporary level of TARGET_EXPRs. */
3178 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3180 /* Restore block_stack level for containing block. */
3182 stack_block_stack = thisblock->data.block.innermost_stack_block;
3183 POPSTACK (block_stack);
3185 /* Pop the stack slot nesting and free any slots at this level. */
3189 /* Generate code to save the stack pointer at the start of the current block
3190 and set up to restore it on exit. */
3193 save_stack_pointer (void)
3195 struct nesting *thisblock = block_stack;
3197 if (thisblock->data.block.stack_level == 0)
3199 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3200 &thisblock->data.block.stack_level,
3201 thisblock->data.block.first_insn);
3202 stack_block_stack = thisblock;
3206 /* Generate RTL for the automatic variable declaration DECL.
3207 (Other kinds of declarations are simply ignored if seen here.) */
3210 expand_decl (tree decl)
3214 type = TREE_TYPE (decl);
3216 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3217 type in case this node is used in a reference. */
3218 if (TREE_CODE (decl) == CONST_DECL)
3220 DECL_MODE (decl) = TYPE_MODE (type);
3221 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3222 DECL_SIZE (decl) = TYPE_SIZE (type);
3223 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3227 /* Otherwise, only automatic variables need any expansion done. Static and
3228 external variables, and external functions, will be handled by
3229 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3230 nothing. PARM_DECLs are handled in `assign_parms'. */
3231 if (TREE_CODE (decl) != VAR_DECL)
3234 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3237 /* Create the RTL representation for the variable. */
3239 if (type == error_mark_node)
3240 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3242 else if (DECL_SIZE (decl) == 0)
3243 /* Variable with incomplete type. */
3246 if (DECL_INITIAL (decl) == 0)
3247 /* Error message was already done; now avoid a crash. */
3248 x = gen_rtx_MEM (BLKmode, const0_rtx);
3250 /* An initializer is going to decide the size of this array.
3251 Until we know the size, represent its address with a reg. */
3252 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3254 set_mem_attributes (x, decl, 1);
3255 SET_DECL_RTL (decl, x);
3257 else if (DECL_MODE (decl) != BLKmode
3258 /* If -ffloat-store, don't put explicit float vars
3260 && !(flag_float_store
3261 && TREE_CODE (type) == REAL_TYPE)
3262 && ! TREE_THIS_VOLATILE (decl)
3263 && ! DECL_NONLOCAL (decl)
3264 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3266 /* Automatic variable that can go in a register. */
3267 int unsignedp = TYPE_UNSIGNED (type);
3268 enum machine_mode reg_mode
3269 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3271 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3273 /* Note if the object is a user variable. */
3274 if (!DECL_ARTIFICIAL (decl))
3276 mark_user_reg (DECL_RTL (decl));
3278 /* Trust user variables which have a pointer type to really
3279 be pointers. Do not trust compiler generated temporaries
3280 as our type system is totally busted as it relates to
3281 pointer arithmetic which translates into lots of compiler
3282 generated objects with pointer types, but which are not really
3284 if (POINTER_TYPE_P (type))
3285 mark_reg_pointer (DECL_RTL (decl),
3286 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3289 maybe_set_unchanging (DECL_RTL (decl), decl);
3291 /* If something wants our address, try to use ADDRESSOF. */
3292 if (TREE_ADDRESSABLE (decl))
3293 put_var_into_stack (decl, /*rescan=*/false);
3296 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3297 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3298 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3299 STACK_CHECK_MAX_VAR_SIZE)))
3301 /* Variable of fixed size that goes on the stack. */
3306 /* If we previously made RTL for this decl, it must be an array
3307 whose size was determined by the initializer.
3308 The old address was a register; set that register now
3309 to the proper address. */
3310 if (DECL_RTL_SET_P (decl))
3312 if (GET_CODE (DECL_RTL (decl)) != MEM
3313 || !REG_P (XEXP (DECL_RTL (decl), 0)))
3315 oldaddr = XEXP (DECL_RTL (decl), 0);
3318 /* Set alignment we actually gave this decl. */
3319 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3320 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3321 DECL_USER_ALIGN (decl) = 0;
3323 x = assign_temp (decl, 1, 1, 1);
3324 set_mem_attributes (x, decl, 1);
3325 SET_DECL_RTL (decl, x);
3329 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3330 if (addr != oldaddr)
3331 emit_move_insn (oldaddr, addr);
3335 /* Dynamic-size object: must push space on the stack. */
3337 rtx address, size, x;
3339 /* Record the stack pointer on entry to block, if have
3340 not already done so. */
3341 do_pending_stack_adjust ();
3342 save_stack_pointer ();
3344 /* Compute the variable's size, in bytes. This will expand any
3345 needed SAVE_EXPRs for the first time. */
3346 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
3349 /* Allocate space on the stack for the variable. Note that
3350 DECL_ALIGN says how the variable is to be aligned and we
3351 cannot use it to conclude anything about the alignment of
3353 address = allocate_dynamic_stack_space (size, NULL_RTX,
3354 TYPE_ALIGN (TREE_TYPE (decl)));
3356 /* Reference the variable indirect through that rtx. */
3357 x = gen_rtx_MEM (DECL_MODE (decl), address);
3358 set_mem_attributes (x, decl, 1);
3359 SET_DECL_RTL (decl, x);
3362 /* Indicate the alignment we actually gave this variable. */
3363 #ifdef STACK_BOUNDARY
3364 DECL_ALIGN (decl) = STACK_BOUNDARY;
3366 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3368 DECL_USER_ALIGN (decl) = 0;
3372 /* Emit code to allocate T_SIZE bytes of dynamic stack space for ALLOC. */
3374 expand_stack_alloc (tree alloc, tree t_size)
3376 rtx address, dest, size;
3379 if (TREE_CODE (alloc) != ADDR_EXPR)
3381 var = TREE_OPERAND (alloc, 0);
3382 if (TREE_CODE (var) != VAR_DECL)
3385 type = TREE_TYPE (var);
3387 /* Compute the variable's size, in bytes. */
3388 size = expand_expr (t_size, NULL_RTX, VOIDmode, 0);
3391 /* Allocate space on the stack for the variable. */
3392 address = XEXP (DECL_RTL (var), 0);
3393 dest = allocate_dynamic_stack_space (size, address, TYPE_ALIGN (type));
3394 if (dest != address)
3395 emit_move_insn (address, dest);
3397 /* Indicate the alignment we actually gave this variable. */
3398 #ifdef STACK_BOUNDARY
3399 DECL_ALIGN (var) = STACK_BOUNDARY;
3401 DECL_ALIGN (var) = BIGGEST_ALIGNMENT;
3403 DECL_USER_ALIGN (var) = 0;
3406 /* Emit code to save the current value of stack. */
3408 expand_stack_save (void)
3412 do_pending_stack_adjust ();
3413 emit_stack_save (SAVE_BLOCK, &ret, NULL_RTX);
3417 /* Emit code to restore the current value of stack. */
3419 expand_stack_restore (tree var)
3421 rtx sa = DECL_RTL (var);
3423 emit_stack_restore (SAVE_BLOCK, sa, NULL_RTX);
3426 /* Emit code to perform the initialization of a declaration DECL. */
3429 expand_decl_init (tree decl)
3431 int was_used = TREE_USED (decl);
3433 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
3434 for static decls. */
3435 if (TREE_CODE (decl) == CONST_DECL
3436 || TREE_STATIC (decl))
3439 /* Compute and store the initial value now. */
3443 if (DECL_INITIAL (decl) == error_mark_node)
3445 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3447 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3448 || code == POINTER_TYPE || code == REFERENCE_TYPE)
3449 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3453 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3455 emit_line_note (DECL_SOURCE_LOCATION (decl));
3456 expand_assignment (decl, DECL_INITIAL (decl), 0);
3460 /* Don't let the initialization count as "using" the variable. */
3461 TREE_USED (decl) = was_used;
3463 /* Free any temporaries we made while initializing the decl. */
3464 preserve_temp_slots (NULL_RTX);
3469 /* CLEANUP is an expression to be executed at exit from this binding contour;
3470 for example, in C++, it might call the destructor for this variable.
3472 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
3473 CLEANUP multiple times, and have the correct semantics. This
3474 happens in exception handling, for gotos, returns, breaks that
3475 leave the current scope.
3477 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3478 that is not associated with any particular variable. */
3481 expand_decl_cleanup (tree decl, tree cleanup)
3483 struct nesting *thisblock;
3485 /* Error if we are not in any block. */
3486 if (cfun == 0 || block_stack == 0)
3489 thisblock = block_stack;
3491 /* Record the cleanup if there is one. */
3497 tree *cleanups = &thisblock->data.block.cleanups;
3498 int cond_context = conditional_context ();
3502 rtx flag = gen_reg_rtx (word_mode);
3507 emit_move_insn (flag, const0_rtx);
3508 set_flag_0 = get_insns ();
3511 thisblock->data.block.last_unconditional_cleanup
3512 = emit_insn_after (set_flag_0,
3513 thisblock->data.block.last_unconditional_cleanup);
3515 emit_move_insn (flag, const1_rtx);
3517 cond = build_decl (VAR_DECL, NULL_TREE,
3518 lang_hooks.types.type_for_mode (word_mode, 1));
3519 SET_DECL_RTL (cond, flag);
3521 /* Conditionalize the cleanup. */
3522 cleanup = build (COND_EXPR, void_type_node,
3523 lang_hooks.truthvalue_conversion (cond),
3524 cleanup, integer_zero_node);
3525 cleanup = fold (cleanup);
3527 cleanups = &thisblock->data.block.cleanups;
3530 cleanup = unsave_expr (cleanup);
3532 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
3535 /* If this block has a cleanup, it belongs in stack_block_stack. */
3536 stack_block_stack = thisblock;
3543 if (! using_eh_for_cleanups_p)
3544 TREE_ADDRESSABLE (t) = 1;
3546 expand_eh_region_start ();
3553 thisblock->data.block.last_unconditional_cleanup
3554 = emit_insn_after (seq,
3555 thisblock->data.block.last_unconditional_cleanup);
3559 thisblock->data.block.last_unconditional_cleanup
3561 /* When we insert instructions after the last unconditional cleanup,
3562 we don't adjust last_insn. That means that a later add_insn will
3563 clobber the instructions we've just added. The easiest way to
3564 fix this is to just insert another instruction here, so that the
3565 instructions inserted after the last unconditional cleanup are
3566 never the last instruction. */
3567 emit_note (NOTE_INSN_DELETED);
3573 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
3577 expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only)
3579 int ret = expand_decl_cleanup (decl, cleanup);
3582 tree node = block_stack->data.block.cleanups;
3583 CLEANUP_EH_ONLY (node) = eh_only;
3588 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3589 DECL_ELTS is the list of elements that belong to DECL's type.
3590 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3593 expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts)
3595 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
3599 /* If any of the elements are addressable, so is the entire union. */
3600 for (t = decl_elts; t; t = TREE_CHAIN (t))
3601 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
3603 TREE_ADDRESSABLE (decl) = 1;
3608 expand_decl_cleanup (decl, cleanup);
3609 x = DECL_RTL (decl);
3611 /* Go through the elements, assigning RTL to each. */
3612 for (t = decl_elts; t; t = TREE_CHAIN (t))
3614 tree decl_elt = TREE_VALUE (t);
3615 tree cleanup_elt = TREE_PURPOSE (t);
3616 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3618 /* If any of the elements are addressable, so is the entire
3620 if (TREE_USED (decl_elt))
3621 TREE_USED (decl) = 1;
3623 /* Propagate the union's alignment to the elements. */
3624 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
3625 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
3627 /* If the element has BLKmode and the union doesn't, the union is
3628 aligned such that the element doesn't need to have BLKmode, so
3629 change the element's mode to the appropriate one for its size. */
3630 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
3631 DECL_MODE (decl_elt) = mode
3632 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
3634 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3635 instead create a new MEM rtx with the proper mode. */
3636 if (GET_CODE (x) == MEM)
3638 if (mode == GET_MODE (x))
3639 SET_DECL_RTL (decl_elt, x);
3641 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
3645 if (mode == GET_MODE (x))
3646 SET_DECL_RTL (decl_elt, x);
3648 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
3653 /* Record the cleanup if there is one. */
3656 thisblock->data.block.cleanups
3657 = tree_cons (decl_elt, cleanup_elt,
3658 thisblock->data.block.cleanups);
3662 /* Expand a list of cleanups LIST.
3663 Elements may be expressions or may be nested lists.
3665 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
3666 goto and handle protection regions specially in that case.
3668 If REACHABLE, we emit code, otherwise just inform the exception handling
3669 code about this finalization. */
3672 expand_cleanups (tree list, int in_fixup, int reachable)
3675 for (tail = list; tail; tail = TREE_CHAIN (tail))
3676 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
3677 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
3680 if (! in_fixup && using_eh_for_cleanups_p)
3681 expand_eh_region_end_cleanup (TREE_VALUE (tail));
3683 if (reachable && !CLEANUP_EH_ONLY (tail))
3685 /* Cleanups may be run multiple times. For example,
3686 when exiting a binding contour, we expand the
3687 cleanups associated with that contour. When a goto
3688 within that binding contour has a target outside that
3689 contour, it will expand all cleanups from its scope to
3690 the target. Though the cleanups are expanded multiple
3691 times, the control paths are non-overlapping so the
3692 cleanups will not be executed twice. */
3694 /* We may need to protect from outer cleanups. */
3695 if (in_fixup && using_eh_for_cleanups_p)
3697 expand_eh_region_start ();
3699 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3701 expand_eh_region_end_fixup (TREE_VALUE (tail));
3704 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3711 /* Mark when the context we are emitting RTL for as a conditional
3712 context, so that any cleanup actions we register with
3713 expand_decl_init will be properly conditionalized when those
3714 cleanup actions are later performed. Must be called before any
3715 expression (tree) is expanded that is within a conditional context. */
3718 start_cleanup_deferral (void)
3720 /* block_stack can be NULL if we are inside the parameter list. It is
3721 OK to do nothing, because cleanups aren't possible here. */
3723 ++block_stack->data.block.conditional_code;
3726 /* Mark the end of a conditional region of code. Because cleanup
3727 deferrals may be nested, we may still be in a conditional region
3728 after we end the currently deferred cleanups, only after we end all
3729 deferred cleanups, are we back in unconditional code. */
3732 end_cleanup_deferral (void)
3734 /* block_stack can be NULL if we are inside the parameter list. It is
3735 OK to do nothing, because cleanups aren't possible here. */
3737 --block_stack->data.block.conditional_code;
3741 last_cleanup_this_contour (void)
3743 if (block_stack == 0)
3746 return block_stack->data.block.cleanups;
3750 /* Return nonzero if any containing block has a stack level or
3754 containing_blocks_have_cleanups_or_stack_level (void)
3756 struct nesting *block;
3758 for (block = block_stack; block; block = block->next)
3759 if (block->data.block.stack_level != 0
3760 || block->data.block.cleanups != 0)
3766 /* Return 1 if there are any pending cleanups at this point.
3767 Check the current contour as well as contours that enclose
3768 the current contour. */
3771 any_pending_cleanups (void)
3773 struct nesting *block;
3775 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
3778 if (block_stack->data.block.cleanups != NULL)
3781 if (block_stack->data.block.outer_cleanups == 0)
3784 for (block = block_stack->next; block; block = block->next)
3785 if (block->data.block.cleanups != 0)
3791 /* Enter a case (Pascal) or switch (C) statement.
3792 Push a block onto case_stack and nesting_stack
3793 to accumulate the case-labels that are seen
3794 and to record the labels generated for the statement.
3796 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
3797 Otherwise, this construct is transparent for `exit_something'.
3799 EXPR is the index-expression to be dispatched on.
3800 TYPE is its nominal type. We could simply convert EXPR to this type,
3801 but instead we take short cuts. */
3804 expand_start_case (int exit_flag, tree expr, tree type,
3805 const char *printname)
3807 struct nesting *thiscase = ALLOC_NESTING ();
3809 /* Make an entry on case_stack for the case we are entering. */
3811 thiscase->desc = CASE_NESTING;
3812 thiscase->next = case_stack;
3813 thiscase->all = nesting_stack;
3814 thiscase->depth = ++nesting_depth;
3815 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
3816 thiscase->data.case_stmt.case_list = 0;
3817 thiscase->data.case_stmt.index_expr = expr;
3818 thiscase->data.case_stmt.nominal_type = type;
3819 thiscase->data.case_stmt.default_label = 0;
3820 thiscase->data.case_stmt.printname = printname;
3821 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
3822 case_stack = thiscase;
3823 nesting_stack = thiscase;
3825 do_pending_stack_adjust ();
3828 /* Make sure case_stmt.start points to something that won't
3829 need any transformation before expand_end_case. */
3830 if (GET_CODE (get_last_insn ()) != NOTE)
3831 emit_note (NOTE_INSN_DELETED);
3833 thiscase->data.case_stmt.start = get_last_insn ();
3835 start_cleanup_deferral ();
3839 check_seenlabel (void)
3841 /* If this is the first label, warn if any insns have been emitted. */
3842 if (case_stack->data.case_stmt.line_number_status >= 0)
3846 restore_line_number_status
3847 (case_stack->data.case_stmt.line_number_status);
3848 case_stack->data.case_stmt.line_number_status = -1;
3850 for (insn = case_stack->data.case_stmt.start;
3852 insn = NEXT_INSN (insn))
3854 if (GET_CODE (insn) == CODE_LABEL)
3856 if (GET_CODE (insn) != NOTE
3857 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
3860 insn = PREV_INSN (insn);
3861 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
3863 /* If insn is zero, then there must have been a syntax error. */
3867 #ifdef USE_MAPPED_LOCATION
3868 locus = NOTE_SOURCE_LOCATION (insn);
3870 locus.file = NOTE_SOURCE_FILE (insn);
3871 locus.line = NOTE_LINE_NUMBER (insn);
3873 warning ("%Hunreachable code at beginning of %s", &locus,
3874 case_stack->data.case_stmt.printname);
3882 /* Accumulate one case or default label inside a case or switch statement.
3883 VALUE is the value of the case (a null pointer, for a default label).
3884 The function CONVERTER, when applied to arguments T and V,
3885 converts the value V to the type T.
3887 If not currently inside a case or switch statement, return 1 and do
3888 nothing. The caller will print a language-specific error message.
3889 If VALUE is a duplicate or overlaps, return 2 and do nothing
3890 except store the (first) duplicate node in *DUPLICATE.
3891 If VALUE is out of range, return 3 and do nothing.
3892 If we are jumping into the scope of a cleanup or var-sized array, return 5.
3893 Return 0 on success.
3895 Extended to handle range statements. */
3898 pushcase (tree value, tree (*converter) (tree, tree), tree label,
3904 /* Fail if not inside a real case statement. */
3905 if (! (case_stack && case_stack->data.case_stmt.start))
3908 if (stack_block_stack
3909 && stack_block_stack->depth > case_stack->depth)
3912 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3913 nominal_type = case_stack->data.case_stmt.nominal_type;
3915 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3916 if (index_type == error_mark_node)
3919 /* Convert VALUE to the type in which the comparisons are nominally done. */
3921 value = (*converter) (nominal_type, value);
3925 /* Fail if this value is out of range for the actual type of the index
3926 (which may be narrower than NOMINAL_TYPE). */
3928 && (TREE_CONSTANT_OVERFLOW (value)
3929 || ! int_fits_type_p (value, index_type)))
3932 return add_case_node (value, value, label, duplicate, false);
3935 /* Like pushcase but this case applies to all values between VALUE1 and
3936 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
3937 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
3938 starts at VALUE1 and ends at the highest value of the index type.
3939 If both are NULL, this case applies to all values.
3941 The return value is the same as that of pushcase but there is one
3942 additional error code: 4 means the specified range was empty. */
3945 pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree),
3946 tree label, tree *duplicate)
3951 /* Fail if not inside a real case statement. */
3952 if (! (case_stack && case_stack->data.case_stmt.start))
3955 if (stack_block_stack
3956 && stack_block_stack->depth > case_stack->depth)
3959 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3960 nominal_type = case_stack->data.case_stmt.nominal_type;
3962 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3963 if (index_type == error_mark_node)
3968 /* Convert VALUEs to type in which the comparisons are nominally done
3969 and replace any unspecified value with the corresponding bound. */
3971 value1 = TYPE_MIN_VALUE (index_type);
3973 value2 = TYPE_MAX_VALUE (index_type);
3975 /* Fail if the range is empty. Do this before any conversion since
3976 we want to allow out-of-range empty ranges. */
3977 if (value2 != 0 && tree_int_cst_lt (value2, value1))
3980 /* If the max was unbounded, use the max of the nominal_type we are
3981 converting to. Do this after the < check above to suppress false
3984 value2 = TYPE_MAX_VALUE (nominal_type);
3986 value1 = (*converter) (nominal_type, value1);
3987 value2 = (*converter) (nominal_type, value2);
3989 /* Fail if these values are out of range. */
3990 if (TREE_CONSTANT_OVERFLOW (value1)
3991 || ! int_fits_type_p (value1, index_type))
3994 if (TREE_CONSTANT_OVERFLOW (value2)
3995 || ! int_fits_type_p (value2, index_type))
3998 return add_case_node (value1, value2, label, duplicate, false);
4001 /* Do the actual insertion of a case label for pushcase and pushcase_range
4002 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4003 slowdown for large switch statements. */
4006 add_case_node (tree low, tree high, tree label, tree *duplicate,
4007 bool dont_expand_label)
4009 struct case_node *p, **q, *r;
4011 /* If there's no HIGH value, then this is not a case range; it's
4012 just a simple case label. But that's just a degenerate case
4017 /* Handle default labels specially. */
4020 if (case_stack->data.case_stmt.default_label != 0)
4022 *duplicate = case_stack->data.case_stmt.default_label;
4025 case_stack->data.case_stmt.default_label = label;
4026 if (!dont_expand_label)
4027 expand_label (label);
4031 q = &case_stack->data.case_stmt.case_list;
4038 /* Keep going past elements distinctly greater than HIGH. */
4039 if (tree_int_cst_lt (high, p->low))
4042 /* or distinctly less than LOW. */
4043 else if (tree_int_cst_lt (p->high, low))
4048 /* We have an overlap; this is an error. */
4049 *duplicate = p->code_label;
4054 /* Add this label to the chain, and succeed. */
4056 r = ggc_alloc (sizeof (struct case_node));
4059 /* If the bounds are equal, turn this into the one-value case. */
4060 if (tree_int_cst_equal (low, high))
4065 r->code_label = label;
4066 if (!dont_expand_label)
4067 expand_label (label);
4077 struct case_node *s;
4083 if (! (b = p->balance))
4084 /* Growth propagation from left side. */
4091 if ((p->left = s = r->right))
4100 if ((r->parent = s))
4108 case_stack->data.case_stmt.case_list = r;
4111 /* r->balance == +1 */
4116 struct case_node *t = r->right;
4118 if ((p->left = s = t->right))
4122 if ((r->right = s = t->left))
4136 if ((t->parent = s))
4144 case_stack->data.case_stmt.case_list = t;
4151 /* p->balance == +1; growth of left side balances the node. */
4161 if (! (b = p->balance))
4162 /* Growth propagation from right side. */
4170 if ((p->right = s = r->left))
4178 if ((r->parent = s))
4187 case_stack->data.case_stmt.case_list = r;
4191 /* r->balance == -1 */
4195 struct case_node *t = r->left;
4197 if ((p->right = s = t->left))
4202 if ((r->left = s = t->right))
4216 if ((t->parent = s))
4225 case_stack->data.case_stmt.case_list = t;
4231 /* p->balance == -1; growth of right side balances the node. */
4244 /* Maximum number of case bit tests. */
4245 #define MAX_CASE_BIT_TESTS 3
4247 /* By default, enable case bit tests on targets with ashlsi3. */
4248 #ifndef CASE_USE_BIT_TESTS
4249 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
4250 != CODE_FOR_nothing)
4254 /* A case_bit_test represents a set of case nodes that may be
4255 selected from using a bit-wise comparison. HI and LO hold
4256 the integer to be tested against, LABEL contains the label
4257 to jump to upon success and BITS counts the number of case
4258 nodes handled by this test, typically the number of bits
4261 struct case_bit_test
4269 /* Determine whether "1 << x" is relatively cheap in word_mode. */
4272 bool lshift_cheap_p (void)
4274 static bool init = false;
4275 static bool cheap = true;
4279 rtx reg = gen_rtx_REG (word_mode, 10000);
4280 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
4281 cheap = cost < COSTS_N_INSNS (3);
4288 /* Comparison function for qsort to order bit tests by decreasing
4289 number of case nodes, i.e. the node with the most cases gets
4293 case_bit_test_cmp (const void *p1, const void *p2)
4295 const struct case_bit_test *d1 = p1;
4296 const struct case_bit_test *d2 = p2;
4298 return d2->bits - d1->bits;
4301 /* Expand a switch statement by a short sequence of bit-wise
4302 comparisons. "switch(x)" is effectively converted into
4303 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
4306 INDEX_EXPR is the value being switched on, which is of
4307 type INDEX_TYPE. MINVAL is the lowest case value of in
4308 the case nodes, of INDEX_TYPE type, and RANGE is highest
4309 value minus MINVAL, also of type INDEX_TYPE. NODES is
4310 the set of case nodes, and DEFAULT_LABEL is the label to
4311 branch to should none of the cases match.
4313 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
4317 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
4318 tree range, case_node_ptr nodes, rtx default_label)
4320 struct case_bit_test test[MAX_CASE_BIT_TESTS];
4321 enum machine_mode mode;
4322 rtx expr, index, label;
4323 unsigned int i,j,lo,hi;
4324 struct case_node *n;
4328 for (n = nodes; n; n = n->right)
4330 label = label_rtx (n->code_label);
4331 for (i = 0; i < count; i++)
4332 if (same_case_target_p (label, test[i].label))
4337 if (count >= MAX_CASE_BIT_TESTS)
4341 test[i].label = label;
4348 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4349 n->low, minval)), 1);
4350 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4351 n->high, minval)), 1);
4352 for (j = lo; j <= hi; j++)
4353 if (j >= HOST_BITS_PER_WIDE_INT)
4354 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
4356 test[i].lo |= (HOST_WIDE_INT) 1 << j;
4359 qsort (test, count, sizeof(*test), case_bit_test_cmp);
4361 index_expr = fold (build (MINUS_EXPR, index_type,
4362 convert (index_type, index_expr),
4363 convert (index_type, minval)));
4364 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4366 index = protect_from_queue (index, 0);
4367 do_pending_stack_adjust ();
4369 mode = TYPE_MODE (index_type);
4370 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
4371 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
4374 index = convert_to_mode (word_mode, index, 0);
4375 index = expand_binop (word_mode, ashl_optab, const1_rtx,
4376 index, NULL_RTX, 1, OPTAB_WIDEN);
4378 for (i = 0; i < count; i++)
4380 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
4381 expr = expand_binop (word_mode, and_optab, index, expr,
4382 NULL_RTX, 1, OPTAB_WIDEN);
4383 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
4384 word_mode, 1, test[i].label);
4387 emit_jump (default_label);
4391 #define HAVE_casesi 0
4394 #ifndef HAVE_tablejump
4395 #define HAVE_tablejump 0
4398 /* Terminate a case (Pascal) or switch (C) statement
4399 in which ORIG_INDEX is the expression to be tested.
4400 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
4401 type as given in the source before any compiler conversions.
4402 Generate the code to test it and jump to the right place. */
4405 expand_end_case_type (tree orig_index, tree orig_type)
4407 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
4408 rtx default_label = 0;
4409 struct case_node *n, *m;
4410 unsigned int count, uniq;
4416 rtx before_case, end, lab;
4417 struct nesting *thiscase = case_stack;
4418 tree index_expr, index_type;
4419 bool exit_done = false;
4422 /* Don't crash due to previous errors. */
4423 if (thiscase == NULL)
4426 index_expr = thiscase->data.case_stmt.index_expr;
4427 index_type = TREE_TYPE (index_expr);
4428 unsignedp = TYPE_UNSIGNED (index_type);
4429 if (orig_type == NULL)
4430 orig_type = TREE_TYPE (orig_index);
4432 do_pending_stack_adjust ();
4434 /* This might get a spurious warning in the presence of a syntax error;
4435 it could be fixed by moving the call to check_seenlabel after the
4436 check for error_mark_node, and copying the code of check_seenlabel that
4437 deals with case_stack->data.case_stmt.line_number_status /
4438 restore_line_number_status in front of the call to end_cleanup_deferral;
4439 However, this might miss some useful warnings in the presence of
4440 non-syntax errors. */
4443 /* An ERROR_MARK occurs for various reasons including invalid data type. */
4444 if (index_type != error_mark_node)
4446 /* If we don't have a default-label, create one here,
4447 after the body of the switch. */
4448 if (thiscase->data.case_stmt.default_label == 0)
4450 thiscase->data.case_stmt.default_label
4451 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
4452 /* Share the exit label if possible. */
4453 if (thiscase->exit_label)
4455 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
4456 thiscase->exit_label);
4459 expand_label (thiscase->data.case_stmt.default_label);
4461 default_label = label_rtx (thiscase->data.case_stmt.default_label);
4463 before_case = get_last_insn ();
4465 if (thiscase->data.case_stmt.case_list
4466 && thiscase->data.case_stmt.case_list->left)
4467 thiscase->data.case_stmt.case_list
4468 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
4470 /* Simplify the case-list before we count it. */
4471 group_case_nodes (thiscase->data.case_stmt.case_list);
4472 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
4475 /* Get upper and lower bounds of case values.
4476 Also convert all the case values to the index expr's data type. */
4480 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4482 /* Check low and high label values are integers. */
4483 if (TREE_CODE (n->low) != INTEGER_CST)
4485 if (TREE_CODE (n->high) != INTEGER_CST)
4488 n->low = convert (index_type, n->low);
4489 n->high = convert (index_type, n->high);
4491 /* Count the elements and track the largest and smallest
4492 of them (treating them as signed even if they are not). */
4500 if (INT_CST_LT (n->low, minval))
4502 if (INT_CST_LT (maxval, n->high))
4505 /* A range counts double, since it requires two compares. */
4506 if (! tree_int_cst_equal (n->low, n->high))
4509 /* Count the number of unique case node targets. */
4511 lab = label_rtx (n->code_label);
4512 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
4513 if (same_case_target_p (label_rtx (m->code_label), lab))
4520 /* Compute span of values. */
4522 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
4524 end_cleanup_deferral ();
4528 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
4530 emit_jump (default_label);
4533 /* Try implementing this switch statement by a short sequence of
4534 bit-wise comparisons. However, we let the binary-tree case
4535 below handle constant index expressions. */
4536 else if (CASE_USE_BIT_TESTS
4537 && ! TREE_CONSTANT (index_expr)
4538 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
4539 && compare_tree_int (range, 0) > 0
4540 && lshift_cheap_p ()
4541 && ((uniq == 1 && count >= 3)
4542 || (uniq == 2 && count >= 5)
4543 || (uniq == 3 && count >= 6)))
4545 /* Optimize the case where all the case values fit in a
4546 word without having to subtract MINVAL. In this case,
4547 we can optimize away the subtraction. */
4548 if (compare_tree_int (minval, 0) > 0
4549 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
4551 minval = integer_zero_node;
4554 emit_case_bit_tests (index_type, index_expr, minval, range,
4555 thiscase->data.case_stmt.case_list,
4559 /* If range of values is much bigger than number of values,
4560 make a sequence of conditional branches instead of a dispatch.
4561 If the switch-index is a constant, do it this way
4562 because we can optimize it. */
4564 else if (count < case_values_threshold ()
4565 || compare_tree_int (range,
4566 (optimize_size ? 3 : 10) * count) > 0
4567 /* RANGE may be signed, and really large ranges will show up
4568 as negative numbers. */
4569 || compare_tree_int (range, 0) < 0
4570 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
4573 || TREE_CONSTANT (index_expr)
4574 /* If neither casesi or tablejump is available, we can
4575 only go this way. */
4576 || (!HAVE_casesi && !HAVE_tablejump))
4578 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4580 /* If the index is a short or char that we do not have
4581 an insn to handle comparisons directly, convert it to
4582 a full integer now, rather than letting each comparison
4583 generate the conversion. */
4585 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
4586 && ! have_insn_for (COMPARE, GET_MODE (index)))
4588 enum machine_mode wider_mode;
4589 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
4590 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
4591 if (have_insn_for (COMPARE, wider_mode))
4593 index = convert_to_mode (wider_mode, index, unsignedp);
4599 do_pending_stack_adjust ();
4601 index = protect_from_queue (index, 0);
4602 if (GET_CODE (index) == MEM)
4603 index = copy_to_reg (index);
4604 if (GET_CODE (index) == CONST_INT
4605 || TREE_CODE (index_expr) == INTEGER_CST)
4607 /* Make a tree node with the proper constant value
4608 if we don't already have one. */
4609 if (TREE_CODE (index_expr) != INTEGER_CST)
4612 = build_int_2 (INTVAL (index),
4613 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
4614 index_expr = convert (index_type, index_expr);
4617 /* For constant index expressions we need only
4618 issue an unconditional branch to the appropriate
4619 target code. The job of removing any unreachable
4620 code is left to the optimization phase if the
4621 "-O" option is specified. */
4622 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4623 if (! tree_int_cst_lt (index_expr, n->low)
4624 && ! tree_int_cst_lt (n->high, index_expr))
4628 emit_jump (label_rtx (n->code_label));
4630 emit_jump (default_label);
4634 /* If the index expression is not constant we generate
4635 a binary decision tree to select the appropriate
4636 target code. This is done as follows:
4638 The list of cases is rearranged into a binary tree,
4639 nearly optimal assuming equal probability for each case.
4641 The tree is transformed into RTL, eliminating
4642 redundant test conditions at the same time.
4644 If program flow could reach the end of the
4645 decision tree an unconditional jump to the
4646 default code is emitted. */
4649 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
4650 && estimate_case_costs (thiscase->data.case_stmt.case_list));
4651 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
4652 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
4653 default_label, index_type);
4654 emit_jump_if_reachable (default_label);
4659 table_label = gen_label_rtx ();
4660 if (! try_casesi (index_type, index_expr, minval, range,
4661 table_label, default_label))
4663 index_type = thiscase->data.case_stmt.nominal_type;
4665 /* Index jumptables from zero for suitable values of
4666 minval to avoid a subtraction. */
4668 && compare_tree_int (minval, 0) > 0
4669 && compare_tree_int (minval, 3) < 0)
4671 minval = integer_zero_node;
4675 if (! try_tablejump (index_type, index_expr, minval, range,
4676 table_label, default_label))
4680 /* Get table of labels to jump to, in order of case index. */
4682 ncases = tree_low_cst (range, 0) + 1;
4683 labelvec = alloca (ncases * sizeof (rtx));
4684 memset (labelvec, 0, ncases * sizeof (rtx));
4686 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4688 /* Compute the low and high bounds relative to the minimum
4689 value since that should fit in a HOST_WIDE_INT while the
4690 actual values may not. */
4692 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4693 n->low, minval)), 1);
4694 HOST_WIDE_INT i_high
4695 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4696 n->high, minval)), 1);
4699 for (i = i_low; i <= i_high; i ++)
4701 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
4704 /* Fill in the gaps with the default. */
4705 for (i = 0; i < ncases; i++)
4706 if (labelvec[i] == 0)
4707 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
4709 /* Output the table. */
4710 emit_label (table_label);
4712 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
4713 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
4714 gen_rtx_LABEL_REF (Pmode, table_label),
4715 gen_rtvec_v (ncases, labelvec),
4716 const0_rtx, const0_rtx));
4718 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
4719 gen_rtvec_v (ncases, labelvec)));
4721 /* If the case insn drops through the table,
4722 after the table we must jump to the default-label.
4723 Otherwise record no drop-through after the table. */
4724 #ifdef CASE_DROPS_THROUGH
4725 emit_jump (default_label);
4731 before_case = NEXT_INSN (before_case);
4732 end = get_last_insn ();
4733 if (squeeze_notes (&before_case, &end))
4735 reorder_insns (before_case, end,
4736 thiscase->data.case_stmt.start);
4739 end_cleanup_deferral ();
4741 if (thiscase->exit_label && !exit_done)
4742 emit_label (thiscase->exit_label);
4744 POPSTACK (case_stack);
4749 /* Convert the tree NODE into a list linked by the right field, with the left
4750 field zeroed. RIGHT is used for recursion; it is a list to be placed
4751 rightmost in the resulting list. */
4753 static struct case_node *
4754 case_tree2list (struct case_node *node, struct case_node *right)
4756 struct case_node *left;
4759 right = case_tree2list (node->right, right);
4761 node->right = right;
4762 if ((left = node->left))
4765 return case_tree2list (left, node);
4771 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
4774 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
4776 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
4782 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
4783 (GET_MODE (op1) == VOIDmode
4784 ? GET_MODE (op2) : GET_MODE (op1)),
4788 /* Not all case values are encountered equally. This function
4789 uses a heuristic to weight case labels, in cases where that
4790 looks like a reasonable thing to do.
4792 Right now, all we try to guess is text, and we establish the
4795 chars above space: 16
4804 If we find any cases in the switch that are not either -1 or in the range
4805 of valid ASCII characters, or are control characters other than those
4806 commonly used with "\", don't treat this switch scanning text.
4808 Return 1 if these nodes are suitable for cost estimation, otherwise
4812 estimate_case_costs (case_node_ptr node)
4814 tree min_ascii = integer_minus_one_node;
4815 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
4819 /* If we haven't already made the cost table, make it now. Note that the
4820 lower bound of the table is -1, not zero. */
4822 if (! cost_table_initialized)
4824 cost_table_initialized = 1;
4826 for (i = 0; i < 128; i++)
4829 COST_TABLE (i) = 16;
4830 else if (ISPUNCT (i))
4832 else if (ISCNTRL (i))
4833 COST_TABLE (i) = -1;
4836 COST_TABLE (' ') = 8;
4837 COST_TABLE ('\t') = 4;
4838 COST_TABLE ('\0') = 4;
4839 COST_TABLE ('\n') = 2;
4840 COST_TABLE ('\f') = 1;
4841 COST_TABLE ('\v') = 1;
4842 COST_TABLE ('\b') = 1;
4845 /* See if all the case expressions look like text. It is text if the
4846 constant is >= -1 and the highest constant is <= 127. Do all comparisons
4847 as signed arithmetic since we don't want to ever access cost_table with a
4848 value less than -1. Also check that none of the constants in a range
4849 are strange control characters. */
4851 for (n = node; n; n = n->right)
4853 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
4856 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
4857 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
4858 if (COST_TABLE (i) < 0)
4862 /* All interesting values are within the range of interesting
4863 ASCII characters. */
4867 /* Determine whether two case labels branch to the same target. */
4870 same_case_target_p (rtx l1, rtx l2)
4878 i1 = next_real_insn (l1);
4879 i2 = next_real_insn (l2);
4883 if (i1 && simplejump_p (i1))
4885 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
4888 if (i2 && simplejump_p (i2))
4890 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
4893 /* When coming from gimple, we usually won't have emitted either
4894 the labels or the body of the switch statement. The job being
4895 done here should be done via jump threading at the tree level.
4896 Cases that go the same place should have the same label. */
4900 /* Delete nodes that branch to the default label from a list of
4901 case nodes. Eg. case 5: default: becomes just default: */
4904 strip_default_case_nodes (case_node_ptr *prev, rtx deflab)
4911 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
4918 /* Scan an ordered list of case nodes
4919 combining those with consecutive values or ranges.
4921 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
4924 group_case_nodes (case_node_ptr head)
4926 case_node_ptr node = head;
4931 case_node_ptr np = node;
4933 lab = label_rtx (node->code_label);
4935 /* Try to group the successors of NODE with NODE. */
4936 while (((np = np->right) != 0)
4937 /* Do they jump to the same place? */
4938 && same_case_target_p (label_rtx (np->code_label), lab)
4939 /* Are their ranges consecutive? */
4940 && tree_int_cst_equal (np->low,
4941 fold (build (PLUS_EXPR,
4942 TREE_TYPE (node->high),
4945 /* An overflow is not consecutive. */
4946 && tree_int_cst_lt (node->high,
4947 fold (build (PLUS_EXPR,
4948 TREE_TYPE (node->high),
4950 integer_one_node))))
4952 node->high = np->high;
4954 /* NP is the first node after NODE which can't be grouped with it.
4955 Delete the nodes in between, and move on to that node. */
4961 /* Take an ordered list of case nodes
4962 and transform them into a near optimal binary tree,
4963 on the assumption that any target code selection value is as
4964 likely as any other.
4966 The transformation is performed by splitting the ordered
4967 list into two equal sections plus a pivot. The parts are
4968 then attached to the pivot as left and right branches. Each
4969 branch is then transformed recursively. */
4972 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
4985 /* Count the number of entries on branch. Also count the ranges. */
4989 if (!tree_int_cst_equal (np->low, np->high))
4993 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
4997 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5005 /* Split this list if it is long enough for that to help. */
5010 /* Find the place in the list that bisects the list's total cost,
5011 Here I gets half the total cost. */
5016 /* Skip nodes while their cost does not reach that amount. */
5017 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5018 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5019 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5022 npp = &(*npp)->right;
5027 /* Leave this branch lopsided, but optimize left-hand
5028 side and fill in `parent' fields for right-hand side. */
5030 np->parent = parent;
5031 balance_case_nodes (&np->left, np);
5032 for (; np->right; np = np->right)
5033 np->right->parent = np;
5037 /* If there are just three nodes, split at the middle one. */
5039 npp = &(*npp)->right;
5042 /* Find the place in the list that bisects the list's total cost,
5043 where ranges count as 2.
5044 Here I gets half the total cost. */
5045 i = (i + ranges + 1) / 2;
5048 /* Skip nodes while their cost does not reach that amount. */
5049 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5054 npp = &(*npp)->right;
5059 np->parent = parent;
5062 /* Optimize each of the two split parts. */
5063 balance_case_nodes (&np->left, np);
5064 balance_case_nodes (&np->right, np);
5068 /* Else leave this branch as one level,
5069 but fill in `parent' fields. */
5071 np->parent = parent;
5072 for (; np->right; np = np->right)
5073 np->right->parent = np;
5078 /* Search the parent sections of the case node tree
5079 to see if a test for the lower bound of NODE would be redundant.
5080 INDEX_TYPE is the type of the index expression.
5082 The instructions to generate the case decision tree are
5083 output in the same order as nodes are processed so it is
5084 known that if a parent node checks the range of the current
5085 node minus one that the current node is bounded at its lower
5086 span. Thus the test would be redundant. */
5089 node_has_low_bound (case_node_ptr node, tree index_type)
5092 case_node_ptr pnode;
5094 /* If the lower bound of this node is the lowest value in the index type,
5095 we need not test it. */
5097 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5100 /* If this node has a left branch, the value at the left must be less
5101 than that at this node, so it cannot be bounded at the bottom and
5102 we need not bother testing any further. */
5107 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5108 node->low, integer_one_node));
5110 /* If the subtraction above overflowed, we can't verify anything.
5111 Otherwise, look for a parent that tests our value - 1. */
5113 if (! tree_int_cst_lt (low_minus_one, node->low))
5116 for (pnode = node->parent; pnode; pnode = pnode->parent)
5117 if (tree_int_cst_equal (low_minus_one, pnode->high))
5123 /* Search the parent sections of the case node tree
5124 to see if a test for the upper bound of NODE would be redundant.
5125 INDEX_TYPE is the type of the index expression.
5127 The instructions to generate the case decision tree are
5128 output in the same order as nodes are processed so it is
5129 known that if a parent node checks the range of the current
5130 node plus one that the current node is bounded at its upper
5131 span. Thus the test would be redundant. */
5134 node_has_high_bound (case_node_ptr node, tree index_type)
5137 case_node_ptr pnode;
5139 /* If there is no upper bound, obviously no test is needed. */
5141 if (TYPE_MAX_VALUE (index_type) == NULL)
5144 /* If the upper bound of this node is the highest value in the type
5145 of the index expression, we need not test against it. */
5147 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5150 /* If this node has a right branch, the value at the right must be greater
5151 than that at this node, so it cannot be bounded at the top and
5152 we need not bother testing any further. */
5157 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5158 node->high, integer_one_node));
5160 /* If the addition above overflowed, we can't verify anything.
5161 Otherwise, look for a parent that tests our value + 1. */
5163 if (! tree_int_cst_lt (node->high, high_plus_one))
5166 for (pnode = node->parent; pnode; pnode = pnode->parent)
5167 if (tree_int_cst_equal (high_plus_one, pnode->low))
5173 /* Search the parent sections of the
5174 case node tree to see if both tests for the upper and lower
5175 bounds of NODE would be redundant. */
5178 node_is_bounded (case_node_ptr node, tree index_type)
5180 return (node_has_low_bound (node, index_type)
5181 && node_has_high_bound (node, index_type));
5184 /* Emit an unconditional jump to LABEL unless it would be dead code. */
5187 emit_jump_if_reachable (rtx label)
5189 if (GET_CODE (get_last_insn ()) != BARRIER)
5193 /* Emit step-by-step code to select a case for the value of INDEX.
5194 The thus generated decision tree follows the form of the
5195 case-node binary tree NODE, whose nodes represent test conditions.
5196 INDEX_TYPE is the type of the index of the switch.
5198 Care is taken to prune redundant tests from the decision tree
5199 by detecting any boundary conditions already checked by
5200 emitted rtx. (See node_has_high_bound, node_has_low_bound
5201 and node_is_bounded, above.)
5203 Where the test conditions can be shown to be redundant we emit
5204 an unconditional jump to the target code. As a further
5205 optimization, the subordinates of a tree node are examined to
5206 check for bounded nodes. In this case conditional and/or
5207 unconditional jumps as a result of the boundary check for the
5208 current node are arranged to target the subordinates associated
5209 code for out of bound conditions on the current node.
5211 We can assume that when control reaches the code generated here,
5212 the index value has already been compared with the parents
5213 of this node, and determined to be on the same side of each parent
5214 as this node is. Thus, if this node tests for the value 51,
5215 and a parent tested for 52, we don't need to consider
5216 the possibility of a value greater than 51. If another parent
5217 tests for the value 50, then this node need not test anything. */
5220 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
5223 /* If INDEX has an unsigned type, we must make unsigned branches. */
5224 int unsignedp = TYPE_UNSIGNED (index_type);
5225 enum machine_mode mode = GET_MODE (index);
5226 enum machine_mode imode = TYPE_MODE (index_type);
5228 /* See if our parents have already tested everything for us.
5229 If they have, emit an unconditional jump for this node. */
5230 if (node_is_bounded (node, index_type))
5231 emit_jump (label_rtx (node->code_label));
5233 else if (tree_int_cst_equal (node->low, node->high))
5235 /* Node is single valued. First see if the index expression matches
5236 this node and then check our children, if any. */
5238 do_jump_if_equal (index,
5239 convert_modes (mode, imode,
5240 expand_expr (node->low, NULL_RTX,
5243 label_rtx (node->code_label), unsignedp);
5245 if (node->right != 0 && node->left != 0)
5247 /* This node has children on both sides.
5248 Dispatch to one side or the other
5249 by comparing the index value with this node's value.
5250 If one subtree is bounded, check that one first,
5251 so we can avoid real branches in the tree. */
5253 if (node_is_bounded (node->right, index_type))
5255 emit_cmp_and_jump_insns (index,
5258 expand_expr (node->high, NULL_RTX,
5261 GT, NULL_RTX, mode, unsignedp,
5262 label_rtx (node->right->code_label));
5263 emit_case_nodes (index, node->left, default_label, index_type);
5266 else if (node_is_bounded (node->left, index_type))
5268 emit_cmp_and_jump_insns (index,
5271 expand_expr (node->high, NULL_RTX,
5274 LT, NULL_RTX, mode, unsignedp,
5275 label_rtx (node->left->code_label));
5276 emit_case_nodes (index, node->right, default_label, index_type);
5279 /* If both children are single-valued cases with no
5280 children, finish up all the work. This way, we can save
5281 one ordered comparison. */
5282 else if (tree_int_cst_equal (node->right->low, node->right->high)
5283 && node->right->left == 0
5284 && node->right->right == 0
5285 && tree_int_cst_equal (node->left->low, node->left->high)
5286 && node->left->left == 0
5287 && node->left->right == 0)
5289 /* Neither node is bounded. First distinguish the two sides;
5290 then emit the code for one side at a time. */
5292 /* See if the value matches what the right hand side
5294 do_jump_if_equal (index,
5295 convert_modes (mode, imode,
5296 expand_expr (node->right->low,
5300 label_rtx (node->right->code_label),
5303 /* See if the value matches what the left hand side
5305 do_jump_if_equal (index,
5306 convert_modes (mode, imode,
5307 expand_expr (node->left->low,
5311 label_rtx (node->left->code_label),
5317 /* Neither node is bounded. First distinguish the two sides;
5318 then emit the code for one side at a time. */
5320 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5322 /* See if the value is on the right. */
5323 emit_cmp_and_jump_insns (index,
5326 expand_expr (node->high, NULL_RTX,
5329 GT, NULL_RTX, mode, unsignedp,
5330 label_rtx (test_label));
5332 /* Value must be on the left.
5333 Handle the left-hand subtree. */
5334 emit_case_nodes (index, node->left, default_label, index_type);
5335 /* If left-hand subtree does nothing,
5337 emit_jump_if_reachable (default_label);
5339 /* Code branches here for the right-hand subtree. */
5340 expand_label (test_label);
5341 emit_case_nodes (index, node->right, default_label, index_type);
5345 else if (node->right != 0 && node->left == 0)
5347 /* Here we have a right child but no left so we issue conditional
5348 branch to default and process the right child.
5350 Omit the conditional branch to default if we it avoid only one
5351 right child; it costs too much space to save so little time. */
5353 if (node->right->right || node->right->left
5354 || !tree_int_cst_equal (node->right->low, node->right->high))
5356 if (!node_has_low_bound (node, index_type))
5358 emit_cmp_and_jump_insns (index,
5361 expand_expr (node->high, NULL_RTX,
5364 LT, NULL_RTX, mode, unsignedp,
5368 emit_case_nodes (index, node->right, default_label, index_type);
5371 /* We cannot process node->right normally
5372 since we haven't ruled out the numbers less than
5373 this node's value. So handle node->right explicitly. */
5374 do_jump_if_equal (index,
5377 expand_expr (node->right->low, NULL_RTX,
5380 label_rtx (node->right->code_label), unsignedp);
5383 else if (node->right == 0 && node->left != 0)
5385 /* Just one subtree, on the left. */
5386 if (node->left->left || node->left->right
5387 || !tree_int_cst_equal (node->left->low, node->left->high))
5389 if (!node_has_high_bound (node, index_type))
5391 emit_cmp_and_jump_insns (index,
5394 expand_expr (node->high, NULL_RTX,
5397 GT, NULL_RTX, mode, unsignedp,
5401 emit_case_nodes (index, node->left, default_label, index_type);
5404 /* We cannot process node->left normally
5405 since we haven't ruled out the numbers less than
5406 this node's value. So handle node->left explicitly. */
5407 do_jump_if_equal (index,
5410 expand_expr (node->left->low, NULL_RTX,
5413 label_rtx (node->left->code_label), unsignedp);
5418 /* Node is a range. These cases are very similar to those for a single
5419 value, except that we do not start by testing whether this node
5420 is the one to branch to. */
5422 if (node->right != 0 && node->left != 0)
5424 /* Node has subtrees on both sides.
5425 If the right-hand subtree is bounded,
5426 test for it first, since we can go straight there.
5427 Otherwise, we need to make a branch in the control structure,
5428 then handle the two subtrees. */
5429 tree test_label = 0;
5431 if (node_is_bounded (node->right, index_type))
5432 /* Right hand node is fully bounded so we can eliminate any
5433 testing and branch directly to the target code. */
5434 emit_cmp_and_jump_insns (index,
5437 expand_expr (node->high, NULL_RTX,
5440 GT, NULL_RTX, mode, unsignedp,
5441 label_rtx (node->right->code_label));
5444 /* Right hand node requires testing.
5445 Branch to a label where we will handle it later. */
5447 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5448 emit_cmp_and_jump_insns (index,
5451 expand_expr (node->high, NULL_RTX,
5454 GT, NULL_RTX, mode, unsignedp,
5455 label_rtx (test_label));
5458 /* Value belongs to this node or to the left-hand subtree. */
5460 emit_cmp_and_jump_insns (index,
5463 expand_expr (node->low, NULL_RTX,
5466 GE, NULL_RTX, mode, unsignedp,
5467 label_rtx (node->code_label));
5469 /* Handle the left-hand subtree. */
5470 emit_case_nodes (index, node->left, default_label, index_type);
5472 /* If right node had to be handled later, do that now. */
5476 /* If the left-hand subtree fell through,
5477 don't let it fall into the right-hand subtree. */
5478 emit_jump_if_reachable (default_label);
5480 expand_label (test_label);
5481 emit_case_nodes (index, node->right, default_label, index_type);
5485 else if (node->right != 0 && node->left == 0)
5487 /* Deal with values to the left of this node,
5488 if they are possible. */
5489 if (!node_has_low_bound (node, index_type))
5491 emit_cmp_and_jump_insns (index,
5494 expand_expr (node->low, NULL_RTX,
5497 LT, NULL_RTX, mode, unsignedp,
5501 /* Value belongs to this node or to the right-hand subtree. */
5503 emit_cmp_and_jump_insns (index,
5506 expand_expr (node->high, NULL_RTX,
5509 LE, NULL_RTX, mode, unsignedp,
5510 label_rtx (node->code_label));
5512 emit_case_nodes (index, node->right, default_label, index_type);
5515 else if (node->right == 0 && node->left != 0)
5517 /* Deal with values to the right of this node,
5518 if they are possible. */
5519 if (!node_has_high_bound (node, index_type))
5521 emit_cmp_and_jump_insns (index,
5524 expand_expr (node->high, NULL_RTX,
5527 GT, NULL_RTX, mode, unsignedp,
5531 /* Value belongs to this node or to the left-hand subtree. */
5533 emit_cmp_and_jump_insns (index,
5536 expand_expr (node->low, NULL_RTX,
5539 GE, NULL_RTX, mode, unsignedp,
5540 label_rtx (node->code_label));
5542 emit_case_nodes (index, node->left, default_label, index_type);
5547 /* Node has no children so we check low and high bounds to remove
5548 redundant tests. Only one of the bounds can exist,
5549 since otherwise this node is bounded--a case tested already. */
5550 int high_bound = node_has_high_bound (node, index_type);
5551 int low_bound = node_has_low_bound (node, index_type);
5553 if (!high_bound && low_bound)
5555 emit_cmp_and_jump_insns (index,
5558 expand_expr (node->high, NULL_RTX,
5561 GT, NULL_RTX, mode, unsignedp,
5565 else if (!low_bound && high_bound)
5567 emit_cmp_and_jump_insns (index,
5570 expand_expr (node->low, NULL_RTX,
5573 LT, NULL_RTX, mode, unsignedp,
5576 else if (!low_bound && !high_bound)
5578 /* Widen LOW and HIGH to the same width as INDEX. */
5579 tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
5580 tree low = build1 (CONVERT_EXPR, type, node->low);
5581 tree high = build1 (CONVERT_EXPR, type, node->high);
5582 rtx low_rtx, new_index, new_bound;
5584 /* Instead of doing two branches, emit one unsigned branch for
5585 (index-low) > (high-low). */
5586 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
5587 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
5588 NULL_RTX, unsignedp,
5590 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
5594 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
5595 mode, 1, default_label);
5598 emit_jump (label_rtx (node->code_label));
5603 #include "gt-stmt.h"