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;
748 if (!cfun->x_whole_function_mode_p)
749 lang_hooks.decls.insert_block (block);
753 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
754 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
759 start = emit_note (NOTE_INSN_BLOCK_BEG);
760 if (cfun->x_whole_function_mode_p)
761 NOTE_BLOCK (start) = block;
762 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
763 end = emit_note (NOTE_INSN_BLOCK_END);
764 if (cfun->x_whole_function_mode_p)
765 NOTE_BLOCK (end) = block;
766 fixup->context = block;
768 emit_insn_after (start, original_before_jump);
771 fixup->block_start_count = current_block_start_count;
772 fixup->stack_level = 0;
773 fixup->cleanup_list_list
774 = ((block->data.block.outer_cleanups
775 || block->data.block.cleanups)
776 ? tree_cons (NULL_TREE, block->data.block.cleanups,
777 block->data.block.outer_cleanups)
779 fixup->next = goto_fixup_chain;
780 goto_fixup_chain = fixup;
786 /* Expand any needed fixups in the outputmost binding level of the
787 function. FIRST_INSN is the first insn in the function. */
790 expand_fixups (rtx first_insn)
792 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
795 /* When exiting a binding contour, process all pending gotos requiring fixups.
796 THISBLOCK is the structure that describes the block being exited.
797 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
798 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
799 FIRST_INSN is the insn that began this contour.
801 Gotos that jump out of this contour must restore the
802 stack level and do the cleanups before actually jumping.
804 DONT_JUMP_IN positive means report error if there is a jump into this
805 contour from before the beginning of the contour. This is also done if
806 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
809 fixup_gotos (struct nesting *thisblock, rtx stack_level,
810 tree cleanup_list, rtx first_insn, int dont_jump_in)
812 struct goto_fixup *f, *prev;
814 /* F is the fixup we are considering; PREV is the previous one. */
815 /* We run this loop in two passes so that cleanups of exited blocks
816 are run first, and blocks that are exited are marked so
819 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
821 /* Test for a fixup that is inactive because it is already handled. */
822 if (f->before_jump == 0)
824 /* Delete inactive fixup from the chain, if that is easy to do. */
826 prev->next = f->next;
828 /* Has this fixup's target label been defined?
829 If so, we can finalize it. */
830 else if (PREV_INSN (f->target_rtl) != 0)
834 /* If this fixup jumped into this contour from before the beginning
835 of this contour, report an error. This code used to use
836 the first non-label insn after f->target_rtl, but that's
837 wrong since such can be added, by things like put_var_into_stack
838 and have INSN_UIDs that are out of the range of the block. */
839 /* ??? Bug: this does not detect jumping in through intermediate
840 blocks that have stack levels or cleanups.
841 It detects only a problem with the innermost block
844 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
846 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
847 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
848 && ! DECL_ERROR_ISSUED (f->target))
850 error ("%Jlabel '%D' used before containing binding contour",
851 f->target, f->target);
852 /* Prevent multiple errors for one label. */
853 DECL_ERROR_ISSUED (f->target) = 1;
856 /* We will expand the cleanups into a sequence of their own and
857 then later on we will attach this new sequence to the insn
858 stream just ahead of the actual jump insn. */
862 /* Temporarily restore the lexical context where we will
863 logically be inserting the fixup code. We do this for the
864 sake of getting the debugging information right. */
866 lang_hooks.decls.pushlevel (0);
867 lang_hooks.decls.set_block (f->context);
869 /* Expand the cleanups for blocks this jump exits. */
870 if (f->cleanup_list_list)
873 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
874 /* Marked elements correspond to blocks that have been closed.
875 Do their cleanups. */
876 if (TREE_ADDRESSABLE (lists)
877 && TREE_VALUE (lists) != 0)
879 expand_cleanups (TREE_VALUE (lists), 1, 1);
880 /* Pop any pushes done in the cleanups,
881 in case function is about to return. */
882 do_pending_stack_adjust ();
886 /* Restore stack level for the biggest contour that this
887 jump jumps out of. */
889 && ! (f->target_rtl == return_label
890 && ((TREE_CODE (TREE_TYPE (current_function_decl))
892 && (TYPE_RETURNS_STACK_DEPRESSED
893 (TREE_TYPE (current_function_decl))))))
894 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
896 /* Finish up the sequence containing the insns which implement the
897 necessary cleanups, and then attach that whole sequence to the
898 insn stream just ahead of the actual jump insn. Attaching it
899 at that point insures that any cleanups which are in fact
900 implicit C++ object destructions (which must be executed upon
901 leaving the block) appear (to the debugger) to be taking place
902 in an area of the generated code where the object(s) being
903 destructed are still "in scope". */
905 cleanup_insns = get_insns ();
906 lang_hooks.decls.poplevel (1, 0, 0);
909 emit_insn_after (cleanup_insns, f->before_jump);
915 /* For any still-undefined labels, do the cleanups for this block now.
916 We must do this now since items in the cleanup list may go out
917 of scope when the block ends. */
918 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
919 if (f->before_jump != 0
920 && PREV_INSN (f->target_rtl) == 0
921 /* Label has still not appeared. If we are exiting a block with
922 a stack level to restore, that started before the fixup,
923 mark this stack level as needing restoration
924 when the fixup is later finalized. */
926 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
927 means the label is undefined. That's erroneous, but possible. */
928 && (thisblock->data.block.block_start_count
929 <= f->block_start_count))
931 tree lists = f->cleanup_list_list;
934 for (; lists; lists = TREE_CHAIN (lists))
935 /* If the following elt. corresponds to our containing block
936 then the elt. must be for this block. */
937 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
940 lang_hooks.decls.pushlevel (0);
941 lang_hooks.decls.set_block (f->context);
942 expand_cleanups (TREE_VALUE (lists), 1, 1);
943 do_pending_stack_adjust ();
944 cleanup_insns = get_insns ();
945 lang_hooks.decls.poplevel (1, 0, 0);
947 if (cleanup_insns != 0)
949 = emit_insn_after (cleanup_insns, f->before_jump);
951 f->cleanup_list_list = TREE_CHAIN (lists);
955 f->stack_level = stack_level;
959 /* Return the number of times character C occurs in string S. */
961 n_occurrences (int c, const char *s)
969 /* Generate RTL for an asm statement (explicit assembler code).
970 STRING is a STRING_CST node containing the assembler code text,
971 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
972 insn is volatile; don't optimize it. */
975 expand_asm (tree string, int vol)
979 if (TREE_CODE (string) == ADDR_EXPR)
980 string = TREE_OPERAND (string, 0);
982 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
984 MEM_VOLATILE_P (body) = vol;
991 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
992 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
993 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
994 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
995 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
996 constraint allows the use of a register operand. And, *IS_INOUT
997 will be true if the operand is read-write, i.e., if it is used as
998 an input as well as an output. If *CONSTRAINT_P is not in
999 canonical form, it will be made canonical. (Note that `+' will be
1000 replaced with `=' as part of this process.)
1002 Returns TRUE if all went well; FALSE if an error occurred. */
1005 parse_output_constraint (const char **constraint_p, int operand_num,
1006 int ninputs, int noutputs, bool *allows_mem,
1007 bool *allows_reg, bool *is_inout)
1009 const char *constraint = *constraint_p;
1012 /* Assume the constraint doesn't allow the use of either a register
1014 *allows_mem = false;
1015 *allows_reg = false;
1017 /* Allow the `=' or `+' to not be at the beginning of the string,
1018 since it wasn't explicitly documented that way, and there is a
1019 large body of code that puts it last. Swap the character to
1020 the front, so as not to uglify any place else. */
1021 p = strchr (constraint, '=');
1023 p = strchr (constraint, '+');
1025 /* If the string doesn't contain an `=', issue an error
1029 error ("output operand constraint lacks `='");
1033 /* If the constraint begins with `+', then the operand is both read
1034 from and written to. */
1035 *is_inout = (*p == '+');
1037 /* Canonicalize the output constraint so that it begins with `='. */
1038 if (p != constraint || is_inout)
1041 size_t c_len = strlen (constraint);
1043 if (p != constraint)
1044 warning ("output constraint `%c' for operand %d is not at the beginning",
1047 /* Make a copy of the constraint. */
1048 buf = alloca (c_len + 1);
1049 strcpy (buf, constraint);
1050 /* Swap the first character and the `=' or `+'. */
1051 buf[p - constraint] = buf[0];
1052 /* Make sure the first character is an `='. (Until we do this,
1053 it might be a `+'.) */
1055 /* Replace the constraint with the canonicalized string. */
1056 *constraint_p = ggc_alloc_string (buf, c_len);
1057 constraint = *constraint_p;
1060 /* Loop through the constraint string. */
1061 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1066 error ("operand constraint contains incorrectly positioned '+' or '='");
1070 if (operand_num + 1 == ninputs + noutputs)
1072 error ("`%%' constraint used with last operand");
1077 case 'V': case 'm': case 'o':
1081 case '?': case '!': case '*': case '&': case '#':
1082 case 'E': case 'F': case 'G': case 'H':
1083 case 's': case 'i': case 'n':
1084 case 'I': case 'J': case 'K': case 'L': case 'M':
1085 case 'N': case 'O': case 'P': case ',':
1088 case '0': case '1': case '2': case '3': case '4':
1089 case '5': case '6': case '7': case '8': case '9':
1091 error ("matching constraint not valid in output operand");
1095 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1096 excepting those that expand_call created. So match memory
1113 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1115 #ifdef EXTRA_CONSTRAINT_STR
1116 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1118 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1122 /* Otherwise we can't assume anything about the nature of
1123 the constraint except that it isn't purely registers.
1124 Treat it like "g" and hope for the best. */
1135 /* Similar, but for input constraints. */
1138 parse_input_constraint (const char **constraint_p, int input_num,
1139 int ninputs, int noutputs, int ninout,
1140 const char * const * constraints,
1141 bool *allows_mem, bool *allows_reg)
1143 const char *constraint = *constraint_p;
1144 const char *orig_constraint = constraint;
1145 size_t c_len = strlen (constraint);
1147 bool saw_match = false;
1149 /* Assume the constraint doesn't allow the use of either
1150 a register or memory. */
1151 *allows_mem = false;
1152 *allows_reg = false;
1154 /* Make sure constraint has neither `=', `+', nor '&'. */
1156 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1157 switch (constraint[j])
1159 case '+': case '=': case '&':
1160 if (constraint == orig_constraint)
1162 error ("input operand constraint contains `%c'", constraint[j]);
1168 if (constraint == orig_constraint
1169 && input_num + 1 == ninputs - ninout)
1171 error ("`%%' constraint used with last operand");
1176 case 'V': case 'm': case 'o':
1181 case '?': case '!': case '*': case '#':
1182 case 'E': case 'F': case 'G': case 'H':
1183 case 's': case 'i': case 'n':
1184 case 'I': case 'J': case 'K': case 'L': case 'M':
1185 case 'N': case 'O': case 'P': case ',':
1188 /* Whether or not a numeric constraint allows a register is
1189 decided by the matching constraint, and so there is no need
1190 to do anything special with them. We must handle them in
1191 the default case, so that we don't unnecessarily force
1192 operands to memory. */
1193 case '0': case '1': case '2': case '3': case '4':
1194 case '5': case '6': case '7': case '8': case '9':
1197 unsigned long match;
1201 match = strtoul (constraint + j, &end, 10);
1202 if (match >= (unsigned long) noutputs)
1204 error ("matching constraint references invalid operand number");
1208 /* Try and find the real constraint for this dup. Only do this
1209 if the matching constraint is the only alternative. */
1211 && (j == 0 || (j == 1 && constraint[0] == '%')))
1213 constraint = constraints[match];
1214 *constraint_p = constraint;
1215 c_len = strlen (constraint);
1217 /* ??? At the end of the loop, we will skip the first part of
1218 the matched constraint. This assumes not only that the
1219 other constraint is an output constraint, but also that
1220 the '=' or '+' come first. */
1224 j = end - constraint;
1225 /* Anticipate increment at end of loop. */
1240 if (! ISALPHA (constraint[j]))
1242 error ("invalid punctuation `%c' in constraint", constraint[j]);
1245 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1248 #ifdef EXTRA_CONSTRAINT_STR
1249 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1251 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1255 /* Otherwise we can't assume anything about the nature of
1256 the constraint except that it isn't purely registers.
1257 Treat it like "g" and hope for the best. */
1265 if (saw_match && !*allows_reg)
1266 warning ("matching constraint does not allow a register");
1271 /* INPUT is one of the input operands from EXPR, an ASM_EXPR. Returns true
1272 if it is an operand which must be passed in memory (i.e. an "m"
1273 constraint), false otherwise. */
1276 asm_op_is_mem_input (tree input, tree expr)
1278 const char *constraint = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (input)));
1279 tree outputs = ASM_OUTPUTS (expr);
1280 int noutputs = list_length (outputs);
1281 const char **constraints
1282 = (const char **) alloca ((noutputs) * sizeof (const char *));
1284 bool allows_mem, allows_reg;
1287 /* Collect output constraints. */
1288 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1289 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1291 /* We pass 0 for input_num, ninputs and ninout; they are only used for
1292 error checking which will be done at expand time. */
1293 parse_input_constraint (&constraint, 0, 0, noutputs, 0, constraints,
1294 &allows_mem, &allows_reg);
1295 return (!allows_reg && allows_mem);
1298 /* Check for overlap between registers marked in CLOBBERED_REGS and
1299 anything inappropriate in DECL. Emit error and return TRUE for error,
1303 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
1305 /* Conflicts between asm-declared register variables and the clobber
1306 list are not allowed. */
1307 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1308 && DECL_REGISTER (decl)
1309 && REG_P (DECL_RTL (decl))
1310 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1312 rtx reg = DECL_RTL (decl);
1315 for (regno = REGNO (reg);
1316 regno < (REGNO (reg)
1317 + hard_regno_nregs[REGNO (reg)][GET_MODE (reg)]);
1319 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1321 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1322 IDENTIFIER_POINTER (DECL_NAME (decl)));
1324 /* Reset registerness to stop multiple errors emitted for a
1326 DECL_REGISTER (decl) = 0;
1333 /* Generate RTL for an asm statement with arguments.
1334 STRING is the instruction template.
1335 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1336 Each output or input has an expression in the TREE_VALUE and
1337 and a tree list in TREE_PURPOSE which in turn contains a constraint
1338 name in TREE_VALUE (or NULL_TREE) and a constraint string
1340 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1341 that is clobbered by this insn.
1343 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1344 Some elements of OUTPUTS may be replaced with trees representing temporary
1345 values. The caller should copy those temporary values to the originally
1348 VOL nonzero means the insn is volatile; don't optimize it. */
1351 expand_asm_operands (tree string, tree outputs, tree inputs,
1352 tree clobbers, int vol, location_t locus)
1354 rtvec argvec, constraintvec;
1356 int ninputs = list_length (inputs);
1357 int noutputs = list_length (outputs);
1360 HARD_REG_SET clobbered_regs;
1361 int clobber_conflict_found = 0;
1365 /* Vector of RTX's of evaluated output operands. */
1366 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
1367 int *inout_opnum = alloca (noutputs * sizeof (int));
1368 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
1369 enum machine_mode *inout_mode
1370 = alloca (noutputs * sizeof (enum machine_mode));
1371 const char **constraints
1372 = alloca ((noutputs + ninputs) * sizeof (const char *));
1373 int old_generating_concat_p = generating_concat_p;
1375 /* An ASM with no outputs needs to be treated as volatile, for now. */
1379 if (! check_operand_nalternatives (outputs, inputs))
1382 string = resolve_asm_operand_names (string, outputs, inputs);
1384 /* Collect constraints. */
1386 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1387 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1388 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1389 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1391 /* Sometimes we wish to automatically clobber registers across an asm.
1392 Case in point is when the i386 backend moved from cc0 to a hard reg --
1393 maintaining source-level compatibility means automatically clobbering
1394 the flags register. */
1395 clobbers = targetm.md_asm_clobbers (clobbers);
1397 /* Count the number of meaningful clobbered registers, ignoring what
1398 we would ignore later. */
1400 CLEAR_HARD_REG_SET (clobbered_regs);
1401 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1403 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1405 i = decode_reg_name (regname);
1406 if (i >= 0 || i == -4)
1409 error ("unknown register name `%s' in `asm'", regname);
1411 /* Mark clobbered registers. */
1414 /* Clobbering the PIC register is an error */
1415 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1417 error ("PIC register `%s' clobbered in `asm'", regname);
1421 SET_HARD_REG_BIT (clobbered_regs, i);
1427 /* First pass over inputs and outputs checks validity and sets
1428 mark_addressable if needed. */
1431 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1433 tree val = TREE_VALUE (tail);
1434 tree type = TREE_TYPE (val);
1435 const char *constraint;
1440 /* If there's an erroneous arg, emit no insn. */
1441 if (type == error_mark_node)
1444 /* Try to parse the output constraint. If that fails, there's
1445 no point in going further. */
1446 constraint = constraints[i];
1447 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1448 &allows_mem, &allows_reg, &is_inout))
1455 && REG_P (DECL_RTL (val))
1456 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1457 lang_hooks.mark_addressable (val);
1464 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1466 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1470 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1472 bool allows_reg, allows_mem;
1473 const char *constraint;
1475 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1476 would get VOIDmode and that could cause a crash in reload. */
1477 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1480 constraint = constraints[i + noutputs];
1481 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1482 constraints, &allows_mem, &allows_reg))
1485 if (! allows_reg && allows_mem)
1486 lang_hooks.mark_addressable (TREE_VALUE (tail));
1489 /* Second pass evaluates arguments. */
1492 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1494 tree val = TREE_VALUE (tail);
1495 tree type = TREE_TYPE (val);
1501 if (!parse_output_constraint (&constraints[i], i, ninputs,
1502 noutputs, &allows_mem, &allows_reg,
1506 /* If an output operand is not a decl or indirect ref and our constraint
1507 allows a register, make a temporary to act as an intermediate.
1508 Make the asm insn write into that, then our caller will copy it to
1509 the real output operand. Likewise for promoted variables. */
1511 generating_concat_p = 0;
1513 real_output_rtx[i] = NULL_RTX;
1514 if ((TREE_CODE (val) == INDIRECT_REF
1517 && (allows_mem || REG_P (DECL_RTL (val)))
1518 && ! (REG_P (DECL_RTL (val))
1519 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1523 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1524 if (GET_CODE (op) == MEM)
1525 op = validize_mem (op);
1527 if (! allows_reg && GET_CODE (op) != MEM)
1528 error ("output number %d not directly addressable", i);
1529 if ((! allows_mem && GET_CODE (op) == MEM)
1530 || GET_CODE (op) == CONCAT)
1532 real_output_rtx[i] = protect_from_queue (op, 1);
1533 op = gen_reg_rtx (GET_MODE (op));
1535 emit_move_insn (op, real_output_rtx[i]);
1540 op = assign_temp (type, 0, 0, 1);
1541 op = validize_mem (op);
1542 TREE_VALUE (tail) = make_tree (type, op);
1546 generating_concat_p = old_generating_concat_p;
1550 inout_mode[ninout] = TYPE_MODE (type);
1551 inout_opnum[ninout++] = i;
1554 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1555 clobber_conflict_found = 1;
1558 /* Make vectors for the expression-rtx, constraint strings,
1559 and named operands. */
1561 argvec = rtvec_alloc (ninputs);
1562 constraintvec = rtvec_alloc (ninputs);
1564 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1565 : GET_MODE (output_rtx[0])),
1566 TREE_STRING_POINTER (string),
1567 empty_string, 0, argvec, constraintvec,
1568 locus.file, locus.line);
1570 MEM_VOLATILE_P (body) = vol;
1572 /* Eval the inputs and put them into ARGVEC.
1573 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1575 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1577 bool allows_reg, allows_mem;
1578 const char *constraint;
1582 constraint = constraints[i + noutputs];
1583 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1584 constraints, &allows_mem, &allows_reg))
1587 generating_concat_p = 0;
1589 val = TREE_VALUE (tail);
1590 type = TREE_TYPE (val);
1591 op = expand_expr (val, NULL_RTX, VOIDmode,
1592 (allows_mem && !allows_reg
1593 ? EXPAND_MEMORY : EXPAND_NORMAL));
1595 /* Never pass a CONCAT to an ASM. */
1596 if (GET_CODE (op) == CONCAT)
1597 op = force_reg (GET_MODE (op), op);
1598 else if (GET_CODE (op) == MEM)
1599 op = validize_mem (op);
1601 if (asm_operand_ok (op, constraint) <= 0)
1604 op = force_reg (TYPE_MODE (type), op);
1605 else if (!allows_mem)
1606 warning ("asm operand %d probably doesn't match constraints",
1608 else if (GET_CODE (op) == MEM)
1610 /* We won't recognize either volatile memory or memory
1611 with a queued address as available a memory_operand
1612 at this point. Ignore it: clearly this *is* a memory. */
1616 warning ("use of memory input without lvalue in "
1617 "asm operand %d is deprecated", i + noutputs);
1619 if (CONSTANT_P (op))
1621 rtx mem = force_const_mem (TYPE_MODE (type), op);
1623 op = validize_mem (mem);
1625 op = force_reg (TYPE_MODE (type), op);
1628 || GET_CODE (op) == SUBREG
1629 || GET_CODE (op) == ADDRESSOF
1630 || GET_CODE (op) == CONCAT)
1632 tree qual_type = build_qualified_type (type,
1634 | TYPE_QUAL_CONST));
1635 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1636 memloc = validize_mem (memloc);
1637 emit_move_insn (memloc, op);
1643 generating_concat_p = old_generating_concat_p;
1644 ASM_OPERANDS_INPUT (body, i) = op;
1646 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1647 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1649 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1650 clobber_conflict_found = 1;
1653 /* Protect all the operands from the queue now that they have all been
1656 generating_concat_p = 0;
1658 for (i = 0; i < ninputs - ninout; i++)
1659 ASM_OPERANDS_INPUT (body, i)
1660 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1662 for (i = 0; i < noutputs; i++)
1663 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1665 /* For in-out operands, copy output rtx to input rtx. */
1666 for (i = 0; i < ninout; i++)
1668 int j = inout_opnum[i];
1671 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1674 sprintf (buffer, "%d", j);
1675 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1676 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
1679 generating_concat_p = old_generating_concat_p;
1681 /* Now, for each output, construct an rtx
1682 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1683 ARGVEC CONSTRAINTS OPNAMES))
1684 If there is more than one, put them inside a PARALLEL. */
1686 if (noutputs == 1 && nclobbers == 0)
1688 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1689 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1692 else if (noutputs == 0 && nclobbers == 0)
1694 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1706 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1708 /* For each output operand, store a SET. */
1709 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1711 XVECEXP (body, 0, i)
1712 = gen_rtx_SET (VOIDmode,
1714 gen_rtx_ASM_OPERANDS
1715 (GET_MODE (output_rtx[i]),
1716 TREE_STRING_POINTER (string),
1717 constraints[i], i, argvec, constraintvec,
1718 locus.file, locus.line));
1720 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1723 /* If there are no outputs (but there are some clobbers)
1724 store the bare ASM_OPERANDS into the PARALLEL. */
1727 XVECEXP (body, 0, i++) = obody;
1729 /* Store (clobber REG) for each clobbered register specified. */
1731 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1733 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1734 int j = decode_reg_name (regname);
1739 if (j == -3) /* `cc', which is not a register */
1742 if (j == -4) /* `memory', don't cache memory across asm */
1744 XVECEXP (body, 0, i++)
1745 = gen_rtx_CLOBBER (VOIDmode,
1748 gen_rtx_SCRATCH (VOIDmode)));
1752 /* Ignore unknown register, error already signaled. */
1756 /* Use QImode since that's guaranteed to clobber just one reg. */
1757 clobbered_reg = gen_rtx_REG (QImode, j);
1759 /* Do sanity check for overlap between clobbers and respectively
1760 input and outputs that hasn't been handled. Such overlap
1761 should have been detected and reported above. */
1762 if (!clobber_conflict_found)
1766 /* We test the old body (obody) contents to avoid tripping
1767 over the under-construction body. */
1768 for (opno = 0; opno < noutputs; opno++)
1769 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1770 internal_error ("asm clobber conflict with output operand");
1772 for (opno = 0; opno < ninputs - ninout; opno++)
1773 if (reg_overlap_mentioned_p (clobbered_reg,
1774 ASM_OPERANDS_INPUT (obody, opno)))
1775 internal_error ("asm clobber conflict with input operand");
1778 XVECEXP (body, 0, i++)
1779 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1785 /* For any outputs that needed reloading into registers, spill them
1786 back to where they belong. */
1787 for (i = 0; i < noutputs; ++i)
1788 if (real_output_rtx[i])
1789 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1795 expand_asm_expr (tree exp)
1801 if (ASM_INPUT_P (exp))
1803 expand_asm (ASM_STRING (exp), ASM_VOLATILE_P (exp));
1807 outputs = ASM_OUTPUTS (exp);
1808 noutputs = list_length (outputs);
1809 /* o[I] is the place that output number I should be written. */
1810 o = (tree *) alloca (noutputs * sizeof (tree));
1812 /* Record the contents of OUTPUTS before it is modified. */
1813 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1814 o[i] = TREE_VALUE (tail);
1816 /* Generate the ASM_OPERANDS insn; store into the TREE_VALUEs of
1817 OUTPUTS some trees for where the values were actually stored. */
1818 expand_asm_operands (ASM_STRING (exp), outputs, ASM_INPUTS (exp),
1819 ASM_CLOBBERS (exp), ASM_VOLATILE_P (exp),
1822 /* Copy all the intermediate outputs into the specified outputs. */
1823 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1825 if (o[i] != TREE_VALUE (tail))
1827 expand_assignment (o[i], TREE_VALUE (tail), 0);
1830 /* Restore the original value so that it's correct the next
1831 time we expand this function. */
1832 TREE_VALUE (tail) = o[i];
1836 /* Those MODIFY_EXPRs could do autoincrements. */
1840 /* A subroutine of expand_asm_operands. Check that all operands have
1841 the same number of alternatives. Return true if so. */
1844 check_operand_nalternatives (tree outputs, tree inputs)
1846 if (outputs || inputs)
1848 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1850 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1853 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1855 error ("too many alternatives in `asm'");
1862 const char *constraint
1863 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1865 if (n_occurrences (',', constraint) != nalternatives)
1867 error ("operand constraints for `asm' differ in number of alternatives");
1871 if (TREE_CHAIN (tmp))
1872 tmp = TREE_CHAIN (tmp);
1874 tmp = next, next = 0;
1881 /* A subroutine of expand_asm_operands. Check that all operand names
1882 are unique. Return true if so. We rely on the fact that these names
1883 are identifiers, and so have been canonicalized by get_identifier,
1884 so all we need are pointer comparisons. */
1887 check_unique_operand_names (tree outputs, tree inputs)
1891 for (i = outputs; i ; i = TREE_CHAIN (i))
1893 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1897 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1898 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1902 for (i = inputs; i ; i = TREE_CHAIN (i))
1904 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1908 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1909 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1911 for (j = outputs; j ; j = TREE_CHAIN (j))
1912 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1919 error ("duplicate asm operand name '%s'",
1920 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1924 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1925 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1926 STRING and in the constraints to those numbers. */
1929 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1936 check_unique_operand_names (outputs, inputs);
1938 /* Substitute [<name>] in input constraint strings. There should be no
1939 named operands in output constraints. */
1940 for (t = inputs; t ; t = TREE_CHAIN (t))
1942 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1943 if (strchr (c, '[') != NULL)
1945 p = buffer = xstrdup (c);
1946 while ((p = strchr (p, '[')) != NULL)
1947 p = resolve_operand_name_1 (p, outputs, inputs);
1948 TREE_VALUE (TREE_PURPOSE (t))
1949 = build_string (strlen (buffer), buffer);
1954 /* Now check for any needed substitutions in the template. */
1955 c = TREE_STRING_POINTER (string);
1956 while ((c = strchr (c, '%')) != NULL)
1960 else if (ISALPHA (c[1]) && c[2] == '[')
1971 /* OK, we need to make a copy so we can perform the substitutions.
1972 Assume that we will not need extra space--we get to remove '['
1973 and ']', which means we cannot have a problem until we have more
1974 than 999 operands. */
1975 buffer = xstrdup (TREE_STRING_POINTER (string));
1976 p = buffer + (c - TREE_STRING_POINTER (string));
1978 while ((p = strchr (p, '%')) != NULL)
1982 else if (ISALPHA (p[1]) && p[2] == '[')
1990 p = resolve_operand_name_1 (p, outputs, inputs);
1993 string = build_string (strlen (buffer), buffer);
2000 /* A subroutine of resolve_operand_names. P points to the '[' for a
2001 potential named operand of the form [<name>]. In place, replace
2002 the name and brackets with a number. Return a pointer to the
2003 balance of the string after substitution. */
2006 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
2013 /* Collect the operand name. */
2014 q = strchr (p, ']');
2017 error ("missing close brace for named operand");
2018 return strchr (p, '\0');
2022 /* Resolve the name to a number. */
2023 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2025 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2028 const char *c = TREE_STRING_POINTER (name);
2029 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2033 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2035 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2038 const char *c = TREE_STRING_POINTER (name);
2039 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2045 error ("undefined named operand '%s'", p + 1);
2049 /* Replace the name with the number. Unfortunately, not all libraries
2050 get the return value of sprintf correct, so search for the end of the
2051 generated string by hand. */
2052 sprintf (p, "%d", op);
2053 p = strchr (p, '\0');
2055 /* Verify the no extra buffer space assumption. */
2059 /* Shift the rest of the buffer down to fill the gap. */
2060 memmove (p, q + 1, strlen (q + 1) + 1);
2065 /* Generate RTL to evaluate the expression EXP
2066 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2067 Provided just for backward-compatibility. expand_expr_stmt_value()
2068 should be used for new code. */
2071 expand_expr_stmt (tree exp)
2073 expand_expr_stmt_value (exp, -1, 1);
2076 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2077 whether to (1) save the value of the expression, (0) discard it or
2078 (-1) use expr_stmts_for_value to tell. The use of -1 is
2079 deprecated, and retained only for backward compatibility. */
2082 expand_expr_stmt_value (tree exp, int want_value, int maybe_last)
2088 if (want_value == -1)
2089 want_value = expr_stmts_for_value != 0;
2091 /* If -Wextra, warn about statements with no side effects,
2092 except for an explicit cast to void (e.g. for assert()), and
2093 except for last statement in ({...}) where they may be useful. */
2095 && (expr_stmts_for_value == 0 || ! maybe_last)
2096 && exp != error_mark_node
2097 && warn_unused_value)
2099 if (TREE_SIDE_EFFECTS (exp))
2100 warn_if_unused_value (exp);
2101 else if (!VOID_TYPE_P (TREE_TYPE (exp)) && !TREE_NO_WARNING (exp))
2102 warning ("%Hstatement with no effect", &emit_locus);
2105 /* If EXP is of function type and we are expanding statements for
2106 value, convert it to pointer-to-function. */
2107 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2108 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2110 /* The call to `expand_expr' could cause last_expr_type and
2111 last_expr_value to get reset. Therefore, we set last_expr_value
2112 and last_expr_type *after* calling expand_expr. */
2113 value = expand_expr_real (exp, want_value ? NULL_RTX : const0_rtx,
2114 VOIDmode, 0, &alt_rtl);
2115 type = TREE_TYPE (exp);
2117 /* If all we do is reference a volatile value in memory,
2118 copy it to a register to be sure it is actually touched. */
2119 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2121 if (TYPE_MODE (type) == VOIDmode)
2123 else if (TYPE_MODE (type) != BLKmode)
2124 value = copy_to_reg (value);
2127 rtx lab = gen_label_rtx ();
2129 /* Compare the value with itself to reference it. */
2130 emit_cmp_and_jump_insns (value, value, EQ,
2131 expand_expr (TYPE_SIZE (type),
2132 NULL_RTX, VOIDmode, 0),
2138 /* If this expression is part of a ({...}) and is in memory, we may have
2139 to preserve temporaries. */
2140 preserve_temp_slots (value);
2142 /* Free any temporaries used to evaluate this expression. Any temporary
2143 used as a result of this expression will already have been preserved
2149 last_expr_value = value;
2150 last_expr_alt_rtl = alt_rtl;
2151 last_expr_type = type;
2157 /* Warn if EXP contains any computations whose results are not used.
2158 Return 1 if a warning is printed; 0 otherwise. */
2161 warn_if_unused_value (tree exp)
2163 if (TREE_USED (exp))
2166 /* Don't warn about void constructs. This includes casting to void,
2167 void function calls, and statement expressions with a final cast
2169 if (VOID_TYPE_P (TREE_TYPE (exp)))
2172 switch (TREE_CODE (exp))
2174 case PREINCREMENT_EXPR:
2175 case POSTINCREMENT_EXPR:
2176 case PREDECREMENT_EXPR:
2177 case POSTDECREMENT_EXPR:
2183 case TRY_CATCH_EXPR:
2184 case WITH_CLEANUP_EXPR:
2189 /* For a binding, warn if no side effect within it. */
2190 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2193 return warn_if_unused_value (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 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2201 if (TREE_NO_WARNING (exp))
2203 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2205 /* Let people do `(foo (), 0)' without a warning. */
2206 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2208 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2212 case NON_LVALUE_EXPR:
2213 /* Don't warn about conversions not explicit in the user's program. */
2214 if (TREE_NO_WARNING (exp))
2216 /* Assignment to a cast usually results in a cast of a modify.
2217 Don't complain about that. There can be an arbitrary number of
2218 casts before the modify, so we must loop until we find the first
2219 non-cast expression and then test to see if that is a modify. */
2221 tree tem = TREE_OPERAND (exp, 0);
2223 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2224 tem = TREE_OPERAND (tem, 0);
2226 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2227 || TREE_CODE (tem) == CALL_EXPR)
2233 /* Don't warn about automatic dereferencing of references, since
2234 the user cannot control it. */
2235 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2236 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2240 /* Referencing a volatile value is a side effect, so don't warn. */
2242 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2243 && TREE_THIS_VOLATILE (exp))
2246 /* If this is an expression which has no operands, there is no value
2247 to be unused. There are no such language-independent codes,
2248 but front ends may define such. */
2249 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2250 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2254 /* If this is an expression with side effects, don't warn. */
2255 if (TREE_SIDE_EFFECTS (exp))
2258 warning ("%Hvalue computed is not used", &emit_locus);
2263 /* Clear out the memory of the last expression evaluated. */
2266 clear_last_expr (void)
2268 last_expr_type = NULL_TREE;
2269 last_expr_value = NULL_RTX;
2270 last_expr_alt_rtl = NULL_RTX;
2273 /* Begin a statement-expression, i.e., a series of statements which
2274 may return a value. Return the RTL_EXPR for this statement expr.
2275 The caller must save that value and pass it to
2276 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2277 in the statement-expression are deallocated at the end of the
2281 expand_start_stmt_expr (int has_scope)
2285 /* Make the RTL_EXPR node temporary, not momentary,
2286 so that rtl_expr_chain doesn't become garbage. */
2287 t = make_node (RTL_EXPR);
2288 do_pending_stack_adjust ();
2290 start_sequence_for_rtl_expr (t);
2294 expr_stmts_for_value++;
2298 /* Restore the previous state at the end of a statement that returns a value.
2299 Returns a tree node representing the statement's value and the
2300 insns to compute the value.
2302 The nodes of that expression have been freed by now, so we cannot use them.
2303 But we don't want to do that anyway; the expression has already been
2304 evaluated and now we just want to use the value. So generate a RTL_EXPR
2305 with the proper type and RTL value.
2307 If the last substatement was not an expression,
2308 return something with type `void'. */
2311 expand_end_stmt_expr (tree t)
2315 if (! last_expr_value || ! last_expr_type)
2317 last_expr_value = const0_rtx;
2318 last_expr_alt_rtl = NULL_RTX;
2319 last_expr_type = void_type_node;
2321 else if (!REG_P (last_expr_value) && ! CONSTANT_P (last_expr_value))
2322 /* Remove any possible QUEUED. */
2323 last_expr_value = protect_from_queue (last_expr_value, 0);
2327 TREE_TYPE (t) = last_expr_type;
2328 RTL_EXPR_RTL (t) = last_expr_value;
2329 RTL_EXPR_ALT_RTL (t) = last_expr_alt_rtl;
2330 RTL_EXPR_SEQUENCE (t) = get_insns ();
2332 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2336 /* Don't consider deleting this expr or containing exprs at tree level. */
2337 TREE_SIDE_EFFECTS (t) = 1;
2338 /* Propagate volatility of the actual RTL expr. */
2339 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2342 expr_stmts_for_value--;
2347 /* Generate RTL for the start of an if-then. COND is the expression
2348 whose truth should be tested.
2350 If EXITFLAG is nonzero, this conditional is visible to
2351 `exit_something'. */
2354 expand_start_cond (tree cond, int exitflag)
2356 struct nesting *thiscond = ALLOC_NESTING ();
2358 /* Make an entry on cond_stack for the cond we are entering. */
2360 thiscond->desc = COND_NESTING;
2361 thiscond->next = cond_stack;
2362 thiscond->all = nesting_stack;
2363 thiscond->depth = ++nesting_depth;
2364 thiscond->data.cond.next_label = gen_label_rtx ();
2365 /* Before we encounter an `else', we don't need a separate exit label
2366 unless there are supposed to be exit statements
2367 to exit this conditional. */
2368 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2369 thiscond->data.cond.endif_label = thiscond->exit_label;
2370 cond_stack = thiscond;
2371 nesting_stack = thiscond;
2373 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2376 /* Generate RTL between then-clause and the elseif-clause
2377 of an if-then-elseif-.... */
2380 expand_start_elseif (tree cond)
2382 if (cond_stack->data.cond.endif_label == 0)
2383 cond_stack->data.cond.endif_label = gen_label_rtx ();
2384 emit_jump (cond_stack->data.cond.endif_label);
2385 emit_label (cond_stack->data.cond.next_label);
2386 cond_stack->data.cond.next_label = gen_label_rtx ();
2387 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2390 /* Generate RTL between the then-clause and the else-clause
2391 of an if-then-else. */
2394 expand_start_else (void)
2396 if (cond_stack->data.cond.endif_label == 0)
2397 cond_stack->data.cond.endif_label = gen_label_rtx ();
2399 emit_jump (cond_stack->data.cond.endif_label);
2400 emit_label (cond_stack->data.cond.next_label);
2401 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2404 /* After calling expand_start_else, turn this "else" into an "else if"
2405 by providing another condition. */
2408 expand_elseif (tree cond)
2410 cond_stack->data.cond.next_label = gen_label_rtx ();
2411 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2414 /* Generate RTL for the end of an if-then.
2415 Pop the record for it off of cond_stack. */
2418 expand_end_cond (void)
2420 struct nesting *thiscond = cond_stack;
2422 do_pending_stack_adjust ();
2423 if (thiscond->data.cond.next_label)
2424 emit_label (thiscond->data.cond.next_label);
2425 if (thiscond->data.cond.endif_label)
2426 emit_label (thiscond->data.cond.endif_label);
2428 POPSTACK (cond_stack);
2432 /* Return nonzero if we should preserve sub-expressions as separate
2433 pseudos. We never do so if we aren't optimizing. We always do so
2434 if -fexpensive-optimizations. */
2437 preserve_subexpressions_p (void)
2439 if (flag_expensive_optimizations)
2442 if (optimize == 0 || cfun == 0 || cfun->stmt == 0)
2449 /* Generate RTL to return from the current function, with no value.
2450 (That is, we do not do anything about returning any value.) */
2453 expand_null_return (void)
2457 last_insn = get_last_insn ();
2459 /* If this function was declared to return a value, but we
2460 didn't, clobber the return registers so that they are not
2461 propagated live to the rest of the function. */
2462 clobber_return_register ();
2464 expand_null_return_1 (last_insn);
2467 /* Generate RTL to return directly from the current function.
2468 (That is, we bypass any return value.) */
2471 expand_naked_return (void)
2473 rtx last_insn, end_label;
2475 last_insn = get_last_insn ();
2476 end_label = naked_return_label;
2478 clear_pending_stack_adjust ();
2479 do_pending_stack_adjust ();
2483 end_label = naked_return_label = gen_label_rtx ();
2484 expand_goto_internal (NULL_TREE, end_label, last_insn);
2487 /* Try to guess whether the value of return means error code. */
2488 static enum br_predictor
2489 return_prediction (rtx val)
2491 /* Different heuristics for pointers and scalars. */
2492 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2494 /* NULL is usually not returned. */
2495 if (val == const0_rtx)
2496 return PRED_NULL_RETURN;
2500 /* Negative return values are often used to indicate
2502 if (GET_CODE (val) == CONST_INT
2503 && INTVAL (val) < 0)
2504 return PRED_NEGATIVE_RETURN;
2505 /* Constant return values are also usually erors,
2506 zero/one often mean booleans so exclude them from the
2508 if (CONSTANT_P (val)
2509 && (val != const0_rtx && val != const1_rtx))
2510 return PRED_CONST_RETURN;
2512 return PRED_NO_PREDICTION;
2516 /* If the current function returns values in the most significant part
2517 of a register, shift return value VAL appropriately. The mode of
2518 the function's return type is known not to be BLKmode. */
2521 shift_return_value (rtx val)
2525 type = TREE_TYPE (DECL_RESULT (current_function_decl));
2526 if (targetm.calls.return_in_msb (type))
2529 HOST_WIDE_INT shift;
2531 target = DECL_RTL (DECL_RESULT (current_function_decl));
2532 shift = (GET_MODE_BITSIZE (GET_MODE (target))
2533 - BITS_PER_UNIT * int_size_in_bytes (type));
2535 val = expand_binop (GET_MODE (target), ashl_optab,
2536 gen_lowpart (GET_MODE (target), val),
2537 GEN_INT (shift), target, 1, OPTAB_WIDEN);
2543 /* Generate RTL to return from the current function, with value VAL. */
2546 expand_value_return (rtx val)
2550 enum br_predictor pred;
2552 if (flag_guess_branch_prob
2553 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2555 /* Emit information for branch prediction. */
2558 note = emit_note (NOTE_INSN_PREDICTION);
2560 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2564 last_insn = get_last_insn ();
2565 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2567 /* Copy the value to the return location
2568 unless it's already there. */
2570 if (return_reg != val)
2572 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2573 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
2575 int unsignedp = TYPE_UNSIGNED (type);
2576 enum machine_mode old_mode
2577 = DECL_MODE (DECL_RESULT (current_function_decl));
2578 enum machine_mode mode
2579 = promote_mode (type, old_mode, &unsignedp, 1);
2581 if (mode != old_mode)
2582 val = convert_modes (mode, old_mode, val, unsignedp);
2584 if (GET_CODE (return_reg) == PARALLEL)
2585 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
2587 emit_move_insn (return_reg, val);
2590 expand_null_return_1 (last_insn);
2593 /* Output a return with no value. If LAST_INSN is nonzero,
2594 pretend that the return takes place after LAST_INSN. */
2597 expand_null_return_1 (rtx last_insn)
2599 rtx end_label = cleanup_label ? cleanup_label : return_label;
2601 clear_pending_stack_adjust ();
2602 do_pending_stack_adjust ();
2606 end_label = return_label = gen_label_rtx ();
2607 expand_goto_internal (NULL_TREE, end_label, last_insn);
2610 /* Generate RTL to evaluate the expression RETVAL and return it
2611 from the current function. */
2614 expand_return (tree retval)
2616 /* If there are any cleanups to be performed, then they will
2617 be inserted following LAST_INSN. It is desirable
2618 that the last_insn, for such purposes, should be the
2619 last insn before computing the return value. Otherwise, cleanups
2620 which call functions can clobber the return value. */
2621 /* ??? rms: I think that is erroneous, because in C++ it would
2622 run destructors on variables that might be used in the subsequent
2623 computation of the return value. */
2629 /* If function wants no value, give it none. */
2630 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2632 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2634 expand_null_return ();
2638 if (retval == error_mark_node)
2640 /* Treat this like a return of no value from a function that
2642 expand_null_return ();
2645 else if (TREE_CODE (retval) == RESULT_DECL)
2646 retval_rhs = retval;
2647 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2648 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2649 retval_rhs = TREE_OPERAND (retval, 1);
2651 retval_rhs = retval;
2653 last_insn = get_last_insn ();
2655 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
2657 /* If the result is an aggregate that is being returned in one (or more)
2658 registers, load the registers here. The compiler currently can't handle
2659 copying a BLKmode value into registers. We could put this code in a
2660 more general area (for use by everyone instead of just function
2661 call/return), but until this feature is generally usable it is kept here
2662 (and in expand_call). The value must go into a pseudo in case there
2663 are cleanups that will clobber the real return register. */
2666 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
2667 && REG_P (result_rtl))
2670 unsigned HOST_WIDE_INT bitpos, xbitpos;
2671 unsigned HOST_WIDE_INT padding_correction = 0;
2672 unsigned HOST_WIDE_INT bytes
2673 = int_size_in_bytes (TREE_TYPE (retval_rhs));
2674 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2675 unsigned int bitsize
2676 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
2677 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
2678 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
2679 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2680 enum machine_mode tmpmode, result_reg_mode;
2684 expand_null_return ();
2688 /* If the structure doesn't take up a whole number of words, see
2689 whether the register value should be padded on the left or on
2690 the right. Set PADDING_CORRECTION to the number of padding
2691 bits needed on the left side.
2693 In most ABIs, the structure will be returned at the least end of
2694 the register, which translates to right padding on little-endian
2695 targets and left padding on big-endian targets. The opposite
2696 holds if the structure is returned at the most significant
2697 end of the register. */
2698 if (bytes % UNITS_PER_WORD != 0
2699 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs))
2701 : BYTES_BIG_ENDIAN))
2702 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
2705 /* Copy the structure BITSIZE bits at a time. */
2706 for (bitpos = 0, xbitpos = padding_correction;
2707 bitpos < bytes * BITS_PER_UNIT;
2708 bitpos += bitsize, xbitpos += bitsize)
2710 /* We need a new destination pseudo each time xbitpos is
2711 on a word boundary and when xbitpos == padding_correction
2712 (the first time through). */
2713 if (xbitpos % BITS_PER_WORD == 0
2714 || xbitpos == padding_correction)
2716 /* Generate an appropriate register. */
2717 dst = gen_reg_rtx (word_mode);
2718 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
2720 /* Clear the destination before we move anything into it. */
2721 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
2724 /* We need a new source operand each time bitpos is on a word
2726 if (bitpos % BITS_PER_WORD == 0)
2727 src = operand_subword_force (result_val,
2728 bitpos / BITS_PER_WORD,
2731 /* Use bitpos for the source extraction (left justified) and
2732 xbitpos for the destination store (right justified). */
2733 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
2734 extract_bit_field (src, bitsize,
2735 bitpos % BITS_PER_WORD, 1,
2736 NULL_RTX, word_mode, word_mode,
2741 tmpmode = GET_MODE (result_rtl);
2742 if (tmpmode == BLKmode)
2744 /* Find the smallest integer mode large enough to hold the
2745 entire structure and use that mode instead of BLKmode
2746 on the USE insn for the return register. */
2747 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
2748 tmpmode != VOIDmode;
2749 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
2750 /* Have we found a large enough mode? */
2751 if (GET_MODE_SIZE (tmpmode) >= bytes)
2754 /* No suitable mode found. */
2755 if (tmpmode == VOIDmode)
2758 PUT_MODE (result_rtl, tmpmode);
2761 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
2762 result_reg_mode = word_mode;
2764 result_reg_mode = tmpmode;
2765 result_reg = gen_reg_rtx (result_reg_mode);
2768 for (i = 0; i < n_regs; i++)
2769 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
2772 if (tmpmode != result_reg_mode)
2773 result_reg = gen_lowpart (tmpmode, result_reg);
2775 expand_value_return (result_reg);
2777 else if (retval_rhs != 0
2778 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
2779 && (REG_P (result_rtl)
2780 || (GET_CODE (result_rtl) == PARALLEL)))
2782 /* Calculate the return value into a temporary (usually a pseudo
2784 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
2785 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
2787 val = assign_temp (nt, 0, 0, 1);
2788 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
2789 val = force_not_mem (val);
2791 /* Return the calculated value, doing cleanups first. */
2792 expand_value_return (shift_return_value (val));
2796 /* No cleanups or no hard reg used;
2797 calculate value into hard return reg. */
2798 expand_expr (retval, const0_rtx, VOIDmode, 0);
2800 expand_value_return (result_rtl);
2804 /* Generate the RTL code for entering a binding contour.
2805 The variables are declared one by one, by calls to `expand_decl'.
2807 FLAGS is a bitwise or of the following flags:
2809 1 - Nonzero if this construct should be visible to
2812 2 - Nonzero if this contour does not require a
2813 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
2814 language-independent code should set this flag because they
2815 will not create corresponding BLOCK nodes. (There should be
2816 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
2817 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
2818 when expand_end_bindings is called.
2820 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
2821 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
2825 expand_start_bindings_and_block (int flags, tree block)
2827 struct nesting *thisblock = ALLOC_NESTING ();
2829 int exit_flag = ((flags & 1) != 0);
2830 int block_flag = ((flags & 2) == 0);
2832 /* If a BLOCK is supplied, then the caller should be requesting a
2833 NOTE_INSN_BLOCK_BEG note. */
2834 if (!block_flag && block)
2837 /* Create a note to mark the beginning of the block. */
2838 if (block_flag && !cfun->dont_emit_block_notes)
2840 note = emit_note (NOTE_INSN_BLOCK_BEG);
2841 NOTE_BLOCK (note) = block;
2844 note = emit_note (NOTE_INSN_DELETED);
2846 /* Make an entry on block_stack for the block we are entering. */
2848 thisblock->desc = BLOCK_NESTING;
2849 thisblock->next = block_stack;
2850 thisblock->all = nesting_stack;
2851 thisblock->depth = ++nesting_depth;
2852 thisblock->data.block.stack_level = 0;
2853 thisblock->data.block.cleanups = 0;
2854 thisblock->data.block.exception_region = 0;
2855 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
2857 thisblock->data.block.conditional_code = 0;
2858 thisblock->data.block.last_unconditional_cleanup = note;
2859 /* When we insert instructions after the last unconditional cleanup,
2860 we don't adjust last_insn. That means that a later add_insn will
2861 clobber the instructions we've just added. The easiest way to
2862 fix this is to just insert another instruction here, so that the
2863 instructions inserted after the last unconditional cleanup are
2864 never the last instruction. */
2865 emit_note (NOTE_INSN_DELETED);
2868 && !(block_stack->data.block.cleanups == NULL_TREE
2869 && block_stack->data.block.outer_cleanups == NULL_TREE))
2870 thisblock->data.block.outer_cleanups
2871 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2872 block_stack->data.block.outer_cleanups);
2874 thisblock->data.block.outer_cleanups = 0;
2875 thisblock->data.block.label_chain = 0;
2876 thisblock->data.block.innermost_stack_block = stack_block_stack;
2877 thisblock->data.block.first_insn = note;
2878 thisblock->data.block.block_start_count = ++current_block_start_count;
2879 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
2880 block_stack = thisblock;
2881 nesting_stack = thisblock;
2883 /* Make a new level for allocating stack slots. */
2887 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
2888 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
2889 expand_expr are made. After we end the region, we know that all
2890 space for all temporaries that were created by TARGET_EXPRs will be
2891 destroyed and their space freed for reuse. */
2894 expand_start_target_temps (void)
2896 /* This is so that even if the result is preserved, the space
2897 allocated will be freed, as we know that it is no longer in use. */
2900 /* Start a new binding layer that will keep track of all cleanup
2901 actions to be performed. */
2902 expand_start_bindings (2);
2904 target_temp_slot_level = temp_slot_level;
2908 expand_end_target_temps (void)
2910 expand_end_bindings (NULL_TREE, 0, 0);
2912 /* This is so that even if the result is preserved, the space
2913 allocated will be freed, as we know that it is no longer in use. */
2917 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
2918 in question represents the outermost pair of curly braces (i.e. the "body
2919 block") of a function or method.
2921 For any BLOCK node representing a "body block" of a function or method, the
2922 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
2923 represents the outermost (function) scope for the function or method (i.e.
2924 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
2925 *that* node in turn will point to the relevant FUNCTION_DECL node. */
2928 is_body_block (tree stmt)
2930 if (lang_hooks.no_body_blocks)
2933 if (TREE_CODE (stmt) == BLOCK)
2935 tree parent = BLOCK_SUPERCONTEXT (stmt);
2937 if (parent && TREE_CODE (parent) == BLOCK)
2939 tree grandparent = BLOCK_SUPERCONTEXT (parent);
2941 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
2949 /* True if we are currently emitting insns in an area of output code
2950 that is controlled by a conditional expression. This is used by
2951 the cleanup handling code to generate conditional cleanup actions. */
2954 conditional_context (void)
2956 return block_stack && block_stack->data.block.conditional_code;
2959 /* Return an opaque pointer to the current nesting level, so frontend code
2960 can check its own sanity. */
2963 current_nesting_level (void)
2965 return cfun ? block_stack : 0;
2968 /* Emit code to restore vital registers at the beginning of a nonlocal goto
2971 expand_nl_goto_receiver (void)
2973 /* Clobber the FP when we get here, so we have to make sure it's
2974 marked as used by this function. */
2975 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
2977 /* Mark the static chain as clobbered here so life information
2978 doesn't get messed up for it. */
2979 emit_insn (gen_rtx_CLOBBER (VOIDmode, static_chain_rtx));
2981 #ifdef HAVE_nonlocal_goto
2982 if (! HAVE_nonlocal_goto)
2984 /* First adjust our frame pointer to its actual value. It was
2985 previously set to the start of the virtual area corresponding to
2986 the stacked variables when we branched here and now needs to be
2987 adjusted to the actual hardware fp value.
2989 Assignments are to virtual registers are converted by
2990 instantiate_virtual_regs into the corresponding assignment
2991 to the underlying register (fp in this case) that makes
2992 the original assignment true.
2993 So the following insn will actually be
2994 decrementing fp by STARTING_FRAME_OFFSET. */
2995 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
2997 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
2998 if (fixed_regs[ARG_POINTER_REGNUM])
3000 #ifdef ELIMINABLE_REGS
3001 /* If the argument pointer can be eliminated in favor of the
3002 frame pointer, we don't need to restore it. We assume here
3003 that if such an elimination is present, it can always be used.
3004 This is the case on all known machines; if we don't make this
3005 assumption, we do unnecessary saving on many machines. */
3006 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3009 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3010 if (elim_regs[i].from == ARG_POINTER_REGNUM
3011 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3014 if (i == ARRAY_SIZE (elim_regs))
3017 /* Now restore our arg pointer from the address at which it
3018 was saved in our stack frame. */
3019 emit_move_insn (virtual_incoming_args_rtx,
3020 copy_to_reg (get_arg_pointer_save_area (cfun)));
3025 #ifdef HAVE_nonlocal_goto_receiver
3026 if (HAVE_nonlocal_goto_receiver)
3027 emit_insn (gen_nonlocal_goto_receiver ());
3030 /* @@@ This is a kludge. Not all machine descriptions define a blockage
3031 insn, but we must not allow the code we just generated to be reordered
3032 by scheduling. Specifically, the update of the frame pointer must
3033 happen immediately, not later. So emit an ASM_INPUT to act as blockage
3035 emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
3038 /* Warn about any unused VARS (which may contain nodes other than
3039 VAR_DECLs, but such nodes are ignored). The nodes are connected
3040 via the TREE_CHAIN field. */
3043 warn_about_unused_variables (tree vars)
3047 if (warn_unused_variable)
3048 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3049 if (TREE_CODE (decl) == VAR_DECL
3050 && ! TREE_USED (decl)
3051 && ! DECL_IN_SYSTEM_HEADER (decl)
3052 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3053 warning ("%Junused variable '%D'", decl, decl);
3056 /* Generate RTL code to terminate a binding contour.
3058 VARS is the chain of VAR_DECL nodes for the variables bound in this
3059 contour. There may actually be other nodes in this chain, but any
3060 nodes other than VAR_DECLS are ignored.
3062 MARK_ENDS is nonzero if we should put a note at the beginning
3063 and end of this binding contour.
3065 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3066 zero if we can jump into this contour only if it does not have a saved
3067 stack level, and negative if we are not to check for invalid use of
3068 labels (because the front end does that). */
3071 expand_end_bindings (tree vars, int mark_ends, int dont_jump_in)
3073 struct nesting *thisblock = block_stack;
3075 /* If any of the variables in this scope were not used, warn the
3077 warn_about_unused_variables (vars);
3079 if (thisblock->exit_label)
3081 do_pending_stack_adjust ();
3082 emit_label (thisblock->exit_label);
3085 /* Don't allow jumping into a block that has a stack level.
3086 Cleanups are allowed, though. */
3087 if (dont_jump_in > 0
3088 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3090 struct label_chain *chain;
3092 /* Any labels in this block are no longer valid to go to.
3093 Mark them to cause an error message. */
3094 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3096 DECL_TOO_LATE (chain->label) = 1;
3097 /* If any goto without a fixup came to this label,
3098 that must be an error, because gotos without fixups
3099 come from outside all saved stack-levels. */
3100 if (TREE_ADDRESSABLE (chain->label))
3101 error ("%Jlabel '%D' used before containing binding contour",
3102 chain->label, chain->label);
3106 /* Restore stack level in effect before the block
3107 (only if variable-size objects allocated). */
3108 /* Perform any cleanups associated with the block. */
3110 if (thisblock->data.block.stack_level != 0
3111 || thisblock->data.block.cleanups != 0)
3116 /* Don't let cleanups affect ({...}) constructs. */
3117 int old_expr_stmts_for_value = expr_stmts_for_value;
3118 rtx old_last_expr_value = last_expr_value;
3119 rtx old_last_expr_alt_rtl = last_expr_alt_rtl;
3120 tree old_last_expr_type = last_expr_type;
3121 expr_stmts_for_value = 0;
3123 /* Only clean up here if this point can actually be reached. */
3124 insn = get_last_insn ();
3125 if (GET_CODE (insn) == NOTE)
3126 insn = prev_nonnote_insn (insn);
3127 reachable = (! insn || GET_CODE (insn) != BARRIER);
3129 /* Do the cleanups. */
3130 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3132 do_pending_stack_adjust ();
3134 expr_stmts_for_value = old_expr_stmts_for_value;
3135 last_expr_value = old_last_expr_value;
3136 last_expr_alt_rtl = old_last_expr_alt_rtl;
3137 last_expr_type = old_last_expr_type;
3139 /* Restore the stack level. */
3141 if (reachable && thisblock->data.block.stack_level != 0)
3143 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3144 thisblock->data.block.stack_level, NULL_RTX);
3145 if (cfun->nonlocal_goto_save_area)
3146 update_nonlocal_goto_save_area ();
3149 /* Any gotos out of this block must also do these things.
3150 Also report any gotos with fixups that came to labels in this
3152 fixup_gotos (thisblock,
3153 thisblock->data.block.stack_level,
3154 thisblock->data.block.cleanups,
3155 thisblock->data.block.first_insn,
3159 /* Mark the beginning and end of the scope if requested.
3160 We do this now, after running cleanups on the variables
3161 just going out of scope, so they are in scope for their cleanups. */
3163 if (mark_ends && !cfun->dont_emit_block_notes)
3165 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3166 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3169 /* Get rid of the beginning-mark if we don't make an end-mark. */
3170 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3172 /* Restore the temporary level of TARGET_EXPRs. */
3173 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3175 /* Restore block_stack level for containing block. */
3177 stack_block_stack = thisblock->data.block.innermost_stack_block;
3178 POPSTACK (block_stack);
3180 /* Pop the stack slot nesting and free any slots at this level. */
3184 /* Generate code to save the stack pointer at the start of the current block
3185 and set up to restore it on exit. */
3188 save_stack_pointer (void)
3190 struct nesting *thisblock = block_stack;
3192 if (thisblock->data.block.stack_level == 0)
3194 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3195 &thisblock->data.block.stack_level,
3196 thisblock->data.block.first_insn);
3197 stack_block_stack = thisblock;
3201 /* Generate RTL for the automatic variable declaration DECL.
3202 (Other kinds of declarations are simply ignored if seen here.) */
3205 expand_decl (tree decl)
3209 type = TREE_TYPE (decl);
3211 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3212 type in case this node is used in a reference. */
3213 if (TREE_CODE (decl) == CONST_DECL)
3215 DECL_MODE (decl) = TYPE_MODE (type);
3216 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3217 DECL_SIZE (decl) = TYPE_SIZE (type);
3218 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3222 /* Otherwise, only automatic variables need any expansion done. Static and
3223 external variables, and external functions, will be handled by
3224 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3225 nothing. PARM_DECLs are handled in `assign_parms'. */
3226 if (TREE_CODE (decl) != VAR_DECL)
3229 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3232 /* Create the RTL representation for the variable. */
3234 if (type == error_mark_node)
3235 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3237 else if (DECL_SIZE (decl) == 0)
3238 /* Variable with incomplete type. */
3241 if (DECL_INITIAL (decl) == 0)
3242 /* Error message was already done; now avoid a crash. */
3243 x = gen_rtx_MEM (BLKmode, const0_rtx);
3245 /* An initializer is going to decide the size of this array.
3246 Until we know the size, represent its address with a reg. */
3247 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3249 set_mem_attributes (x, decl, 1);
3250 SET_DECL_RTL (decl, x);
3252 else if (DECL_MODE (decl) != BLKmode
3253 /* If -ffloat-store, don't put explicit float vars
3255 && !(flag_float_store
3256 && TREE_CODE (type) == REAL_TYPE)
3257 && ! TREE_THIS_VOLATILE (decl)
3258 && ! DECL_NONLOCAL (decl)
3259 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3261 /* Automatic variable that can go in a register. */
3262 int unsignedp = TYPE_UNSIGNED (type);
3263 enum machine_mode reg_mode
3264 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3266 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3268 /* Note if the object is a user variable. */
3269 if (!DECL_ARTIFICIAL (decl))
3271 mark_user_reg (DECL_RTL (decl));
3273 /* Trust user variables which have a pointer type to really
3274 be pointers. Do not trust compiler generated temporaries
3275 as our type system is totally busted as it relates to
3276 pointer arithmetic which translates into lots of compiler
3277 generated objects with pointer types, but which are not really
3279 if (POINTER_TYPE_P (type))
3280 mark_reg_pointer (DECL_RTL (decl),
3281 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3284 maybe_set_unchanging (DECL_RTL (decl), decl);
3286 /* If something wants our address, try to use ADDRESSOF. */
3287 if (TREE_ADDRESSABLE (decl))
3288 put_var_into_stack (decl, /*rescan=*/false);
3291 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3292 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3293 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3294 STACK_CHECK_MAX_VAR_SIZE)))
3296 /* Variable of fixed size that goes on the stack. */
3301 /* If we previously made RTL for this decl, it must be an array
3302 whose size was determined by the initializer.
3303 The old address was a register; set that register now
3304 to the proper address. */
3305 if (DECL_RTL_SET_P (decl))
3307 if (GET_CODE (DECL_RTL (decl)) != MEM
3308 || !REG_P (XEXP (DECL_RTL (decl), 0)))
3310 oldaddr = XEXP (DECL_RTL (decl), 0);
3313 /* Set alignment we actually gave this decl. */
3314 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3315 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3316 DECL_USER_ALIGN (decl) = 0;
3318 x = assign_temp (decl, 1, 1, 1);
3319 set_mem_attributes (x, decl, 1);
3320 SET_DECL_RTL (decl, x);
3324 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3325 if (addr != oldaddr)
3326 emit_move_insn (oldaddr, addr);
3330 /* Dynamic-size object: must push space on the stack. */
3332 rtx address, size, x;
3334 /* Record the stack pointer on entry to block, if have
3335 not already done so. */
3336 do_pending_stack_adjust ();
3337 save_stack_pointer ();
3339 /* Compute the variable's size, in bytes. This will expand any
3340 needed SAVE_EXPRs for the first time. */
3341 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
3344 /* Allocate space on the stack for the variable. Note that
3345 DECL_ALIGN says how the variable is to be aligned and we
3346 cannot use it to conclude anything about the alignment of
3348 address = allocate_dynamic_stack_space (size, NULL_RTX,
3349 TYPE_ALIGN (TREE_TYPE (decl)));
3351 /* Reference the variable indirect through that rtx. */
3352 x = gen_rtx_MEM (DECL_MODE (decl), address);
3353 set_mem_attributes (x, decl, 1);
3354 SET_DECL_RTL (decl, x);
3357 /* Indicate the alignment we actually gave this variable. */
3358 #ifdef STACK_BOUNDARY
3359 DECL_ALIGN (decl) = STACK_BOUNDARY;
3361 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3363 DECL_USER_ALIGN (decl) = 0;
3367 /* Emit code to allocate T_SIZE bytes of dynamic stack space for ALLOC. */
3369 expand_stack_alloc (tree alloc, tree t_size)
3371 rtx address, dest, size;
3374 if (TREE_CODE (alloc) != ADDR_EXPR)
3376 var = TREE_OPERAND (alloc, 0);
3377 if (TREE_CODE (var) != VAR_DECL)
3380 type = TREE_TYPE (var);
3382 /* In function-at-a-time mode, variable_size doesn't expand this,
3384 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3385 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3386 const0_rtx, VOIDmode, 0);
3388 /* Compute the variable's size, in bytes. */
3389 size = expand_expr (t_size, NULL_RTX, VOIDmode, 0);
3392 /* Allocate space on the stack for the variable. */
3393 address = XEXP (DECL_RTL (var), 0);
3394 dest = allocate_dynamic_stack_space (size, address, TYPE_ALIGN (type));
3395 if (dest != address)
3396 emit_move_insn (address, dest);
3398 /* Indicate the alignment we actually gave this variable. */
3399 #ifdef STACK_BOUNDARY
3400 DECL_ALIGN (var) = STACK_BOUNDARY;
3402 DECL_ALIGN (var) = BIGGEST_ALIGNMENT;
3404 DECL_USER_ALIGN (var) = 0;
3407 /* Emit code to save the current value of stack. */
3409 expand_stack_save (void)
3413 do_pending_stack_adjust ();
3414 emit_stack_save (SAVE_BLOCK, &ret, NULL_RTX);
3418 /* Emit code to restore the current value of stack. */
3420 expand_stack_restore (tree var)
3422 rtx sa = DECL_RTL (var);
3424 emit_stack_restore (SAVE_BLOCK, sa, NULL_RTX);
3427 /* Emit code to perform the initialization of a declaration DECL. */
3430 expand_decl_init (tree decl)
3432 int was_used = TREE_USED (decl);
3434 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
3435 for static decls. */
3436 if (TREE_CODE (decl) == CONST_DECL
3437 || TREE_STATIC (decl))
3440 /* Compute and store the initial value now. */
3444 if (DECL_INITIAL (decl) == error_mark_node)
3446 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3448 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3449 || code == POINTER_TYPE || code == REFERENCE_TYPE)
3450 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3454 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3456 emit_line_note (DECL_SOURCE_LOCATION (decl));
3457 expand_assignment (decl, DECL_INITIAL (decl), 0);
3461 /* Don't let the initialization count as "using" the variable. */
3462 TREE_USED (decl) = was_used;
3464 /* Free any temporaries we made while initializing the decl. */
3465 preserve_temp_slots (NULL_RTX);
3470 /* CLEANUP is an expression to be executed at exit from this binding contour;
3471 for example, in C++, it might call the destructor for this variable.
3473 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
3474 CLEANUP multiple times, and have the correct semantics. This
3475 happens in exception handling, for gotos, returns, breaks that
3476 leave the current scope.
3478 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3479 that is not associated with any particular variable. */
3482 expand_decl_cleanup (tree decl, tree cleanup)
3484 struct nesting *thisblock;
3486 /* Error if we are not in any block. */
3487 if (cfun == 0 || block_stack == 0)
3490 thisblock = block_stack;
3492 /* Record the cleanup if there is one. */
3498 tree *cleanups = &thisblock->data.block.cleanups;
3499 int cond_context = conditional_context ();
3503 rtx flag = gen_reg_rtx (word_mode);
3508 emit_move_insn (flag, const0_rtx);
3509 set_flag_0 = get_insns ();
3512 thisblock->data.block.last_unconditional_cleanup
3513 = emit_insn_after (set_flag_0,
3514 thisblock->data.block.last_unconditional_cleanup);
3516 emit_move_insn (flag, const1_rtx);
3518 cond = build_decl (VAR_DECL, NULL_TREE,
3519 lang_hooks.types.type_for_mode (word_mode, 1));
3520 SET_DECL_RTL (cond, flag);
3522 /* Conditionalize the cleanup. */
3523 cleanup = build (COND_EXPR, void_type_node,
3524 lang_hooks.truthvalue_conversion (cond),
3525 cleanup, integer_zero_node);
3526 cleanup = fold (cleanup);
3528 cleanups = &thisblock->data.block.cleanups;
3531 cleanup = unsave_expr (cleanup);
3533 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
3536 /* If this block has a cleanup, it belongs in stack_block_stack. */
3537 stack_block_stack = thisblock;
3544 if (! using_eh_for_cleanups_p)
3545 TREE_ADDRESSABLE (t) = 1;
3547 expand_eh_region_start ();
3554 thisblock->data.block.last_unconditional_cleanup
3555 = emit_insn_after (seq,
3556 thisblock->data.block.last_unconditional_cleanup);
3560 thisblock->data.block.last_unconditional_cleanup
3562 /* When we insert instructions after the last unconditional cleanup,
3563 we don't adjust last_insn. That means that a later add_insn will
3564 clobber the instructions we've just added. The easiest way to
3565 fix this is to just insert another instruction here, so that the
3566 instructions inserted after the last unconditional cleanup are
3567 never the last instruction. */
3568 emit_note (NOTE_INSN_DELETED);
3574 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
3578 expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only)
3580 int ret = expand_decl_cleanup (decl, cleanup);
3583 tree node = block_stack->data.block.cleanups;
3584 CLEANUP_EH_ONLY (node) = eh_only;
3589 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3590 DECL_ELTS is the list of elements that belong to DECL's type.
3591 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3594 expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts)
3596 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
3600 /* If any of the elements are addressable, so is the entire union. */
3601 for (t = decl_elts; t; t = TREE_CHAIN (t))
3602 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
3604 TREE_ADDRESSABLE (decl) = 1;
3609 expand_decl_cleanup (decl, cleanup);
3610 x = DECL_RTL (decl);
3612 /* Go through the elements, assigning RTL to each. */
3613 for (t = decl_elts; t; t = TREE_CHAIN (t))
3615 tree decl_elt = TREE_VALUE (t);
3616 tree cleanup_elt = TREE_PURPOSE (t);
3617 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3619 /* If any of the elements are addressable, so is the entire
3621 if (TREE_USED (decl_elt))
3622 TREE_USED (decl) = 1;
3624 /* Propagate the union's alignment to the elements. */
3625 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
3626 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
3628 /* If the element has BLKmode and the union doesn't, the union is
3629 aligned such that the element doesn't need to have BLKmode, so
3630 change the element's mode to the appropriate one for its size. */
3631 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
3632 DECL_MODE (decl_elt) = mode
3633 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
3635 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3636 instead create a new MEM rtx with the proper mode. */
3637 if (GET_CODE (x) == MEM)
3639 if (mode == GET_MODE (x))
3640 SET_DECL_RTL (decl_elt, x);
3642 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
3646 if (mode == GET_MODE (x))
3647 SET_DECL_RTL (decl_elt, x);
3649 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
3654 /* Record the cleanup if there is one. */
3657 thisblock->data.block.cleanups
3658 = tree_cons (decl_elt, cleanup_elt,
3659 thisblock->data.block.cleanups);
3663 /* Expand a list of cleanups LIST.
3664 Elements may be expressions or may be nested lists.
3666 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
3667 goto and handle protection regions specially in that case.
3669 If REACHABLE, we emit code, otherwise just inform the exception handling
3670 code about this finalization. */
3673 expand_cleanups (tree list, int in_fixup, int reachable)
3676 for (tail = list; tail; tail = TREE_CHAIN (tail))
3677 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
3678 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
3681 if (! in_fixup && using_eh_for_cleanups_p)
3682 expand_eh_region_end_cleanup (TREE_VALUE (tail));
3684 if (reachable && !CLEANUP_EH_ONLY (tail))
3686 /* Cleanups may be run multiple times. For example,
3687 when exiting a binding contour, we expand the
3688 cleanups associated with that contour. When a goto
3689 within that binding contour has a target outside that
3690 contour, it will expand all cleanups from its scope to
3691 the target. Though the cleanups are expanded multiple
3692 times, the control paths are non-overlapping so the
3693 cleanups will not be executed twice. */
3695 /* We may need to protect from outer cleanups. */
3696 if (in_fixup && using_eh_for_cleanups_p)
3698 expand_eh_region_start ();
3700 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3702 expand_eh_region_end_fixup (TREE_VALUE (tail));
3705 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3712 /* Mark when the context we are emitting RTL for as a conditional
3713 context, so that any cleanup actions we register with
3714 expand_decl_init will be properly conditionalized when those
3715 cleanup actions are later performed. Must be called before any
3716 expression (tree) is expanded that is within a conditional context. */
3719 start_cleanup_deferral (void)
3721 /* block_stack can be NULL if we are inside the parameter list. It is
3722 OK to do nothing, because cleanups aren't possible here. */
3724 ++block_stack->data.block.conditional_code;
3727 /* Mark the end of a conditional region of code. Because cleanup
3728 deferrals may be nested, we may still be in a conditional region
3729 after we end the currently deferred cleanups, only after we end all
3730 deferred cleanups, are we back in unconditional code. */
3733 end_cleanup_deferral (void)
3735 /* block_stack can be NULL if we are inside the parameter list. It is
3736 OK to do nothing, because cleanups aren't possible here. */
3738 --block_stack->data.block.conditional_code;
3742 last_cleanup_this_contour (void)
3744 if (block_stack == 0)
3747 return block_stack->data.block.cleanups;
3751 /* Return nonzero if any containing block has a stack level or
3755 containing_blocks_have_cleanups_or_stack_level (void)
3757 struct nesting *block;
3759 for (block = block_stack; block; block = block->next)
3760 if (block->data.block.stack_level != 0
3761 || block->data.block.cleanups != 0)
3767 /* Return 1 if there are any pending cleanups at this point.
3768 Check the current contour as well as contours that enclose
3769 the current contour. */
3772 any_pending_cleanups (void)
3774 struct nesting *block;
3776 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
3779 if (block_stack->data.block.cleanups != NULL)
3782 if (block_stack->data.block.outer_cleanups == 0)
3785 for (block = block_stack->next; block; block = block->next)
3786 if (block->data.block.cleanups != 0)
3792 /* Enter a case (Pascal) or switch (C) statement.
3793 Push a block onto case_stack and nesting_stack
3794 to accumulate the case-labels that are seen
3795 and to record the labels generated for the statement.
3797 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
3798 Otherwise, this construct is transparent for `exit_something'.
3800 EXPR is the index-expression to be dispatched on.
3801 TYPE is its nominal type. We could simply convert EXPR to this type,
3802 but instead we take short cuts. */
3805 expand_start_case (int exit_flag, tree expr, tree type,
3806 const char *printname)
3808 struct nesting *thiscase = ALLOC_NESTING ();
3810 /* Make an entry on case_stack for the case we are entering. */
3812 thiscase->desc = CASE_NESTING;
3813 thiscase->next = case_stack;
3814 thiscase->all = nesting_stack;
3815 thiscase->depth = ++nesting_depth;
3816 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
3817 thiscase->data.case_stmt.case_list = 0;
3818 thiscase->data.case_stmt.index_expr = expr;
3819 thiscase->data.case_stmt.nominal_type = type;
3820 thiscase->data.case_stmt.default_label = 0;
3821 thiscase->data.case_stmt.printname = printname;
3822 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
3823 case_stack = thiscase;
3824 nesting_stack = thiscase;
3826 do_pending_stack_adjust ();
3829 /* Make sure case_stmt.start points to something that won't
3830 need any transformation before expand_end_case. */
3831 if (GET_CODE (get_last_insn ()) != NOTE)
3832 emit_note (NOTE_INSN_DELETED);
3834 thiscase->data.case_stmt.start = get_last_insn ();
3836 start_cleanup_deferral ();
3840 check_seenlabel (void)
3842 /* If this is the first label, warn if any insns have been emitted. */
3843 if (case_stack->data.case_stmt.line_number_status >= 0)
3847 restore_line_number_status
3848 (case_stack->data.case_stmt.line_number_status);
3849 case_stack->data.case_stmt.line_number_status = -1;
3851 for (insn = case_stack->data.case_stmt.start;
3853 insn = NEXT_INSN (insn))
3855 if (GET_CODE (insn) == CODE_LABEL)
3857 if (GET_CODE (insn) != NOTE
3858 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
3861 insn = PREV_INSN (insn);
3862 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
3864 /* If insn is zero, then there must have been a syntax error. */
3868 locus.file = NOTE_SOURCE_FILE (insn);
3869 locus.line = NOTE_LINE_NUMBER (insn);
3870 warning ("%Hunreachable code at beginning of %s", &locus,
3871 case_stack->data.case_stmt.printname);
3879 /* Accumulate one case or default label inside a case or switch statement.
3880 VALUE is the value of the case (a null pointer, for a default label).
3881 The function CONVERTER, when applied to arguments T and V,
3882 converts the value V to the type T.
3884 If not currently inside a case or switch statement, return 1 and do
3885 nothing. The caller will print a language-specific error message.
3886 If VALUE is a duplicate or overlaps, return 2 and do nothing
3887 except store the (first) duplicate node in *DUPLICATE.
3888 If VALUE is out of range, return 3 and do nothing.
3889 If we are jumping into the scope of a cleanup or var-sized array, return 5.
3890 Return 0 on success.
3892 Extended to handle range statements. */
3895 pushcase (tree value, tree (*converter) (tree, tree), tree label,
3901 /* Fail if not inside a real case statement. */
3902 if (! (case_stack && case_stack->data.case_stmt.start))
3905 if (stack_block_stack
3906 && stack_block_stack->depth > case_stack->depth)
3909 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3910 nominal_type = case_stack->data.case_stmt.nominal_type;
3912 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3913 if (index_type == error_mark_node)
3916 /* Convert VALUE to the type in which the comparisons are nominally done. */
3918 value = (*converter) (nominal_type, value);
3922 /* Fail if this value is out of range for the actual type of the index
3923 (which may be narrower than NOMINAL_TYPE). */
3925 && (TREE_CONSTANT_OVERFLOW (value)
3926 || ! int_fits_type_p (value, index_type)))
3929 return add_case_node (value, value, label, duplicate, false);
3932 /* Like pushcase but this case applies to all values between VALUE1 and
3933 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
3934 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
3935 starts at VALUE1 and ends at the highest value of the index type.
3936 If both are NULL, this case applies to all values.
3938 The return value is the same as that of pushcase but there is one
3939 additional error code: 4 means the specified range was empty. */
3942 pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree),
3943 tree label, tree *duplicate)
3948 /* Fail if not inside a real case statement. */
3949 if (! (case_stack && case_stack->data.case_stmt.start))
3952 if (stack_block_stack
3953 && stack_block_stack->depth > case_stack->depth)
3956 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3957 nominal_type = case_stack->data.case_stmt.nominal_type;
3959 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3960 if (index_type == error_mark_node)
3965 /* Convert VALUEs to type in which the comparisons are nominally done
3966 and replace any unspecified value with the corresponding bound. */
3968 value1 = TYPE_MIN_VALUE (index_type);
3970 value2 = TYPE_MAX_VALUE (index_type);
3972 /* Fail if the range is empty. Do this before any conversion since
3973 we want to allow out-of-range empty ranges. */
3974 if (value2 != 0 && tree_int_cst_lt (value2, value1))
3977 /* If the max was unbounded, use the max of the nominal_type we are
3978 converting to. Do this after the < check above to suppress false
3981 value2 = TYPE_MAX_VALUE (nominal_type);
3983 value1 = (*converter) (nominal_type, value1);
3984 value2 = (*converter) (nominal_type, value2);
3986 /* Fail if these values are out of range. */
3987 if (TREE_CONSTANT_OVERFLOW (value1)
3988 || ! int_fits_type_p (value1, index_type))
3991 if (TREE_CONSTANT_OVERFLOW (value2)
3992 || ! int_fits_type_p (value2, index_type))
3995 return add_case_node (value1, value2, label, duplicate, false);
3998 /* Do the actual insertion of a case label for pushcase and pushcase_range
3999 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4000 slowdown for large switch statements. */
4003 add_case_node (tree low, tree high, tree label, tree *duplicate,
4004 bool dont_expand_label)
4006 struct case_node *p, **q, *r;
4008 /* If there's no HIGH value, then this is not a case range; it's
4009 just a simple case label. But that's just a degenerate case
4014 /* Handle default labels specially. */
4017 if (case_stack->data.case_stmt.default_label != 0)
4019 *duplicate = case_stack->data.case_stmt.default_label;
4022 case_stack->data.case_stmt.default_label = label;
4023 if (!dont_expand_label)
4024 expand_label (label);
4028 q = &case_stack->data.case_stmt.case_list;
4035 /* Keep going past elements distinctly greater than HIGH. */
4036 if (tree_int_cst_lt (high, p->low))
4039 /* or distinctly less than LOW. */
4040 else if (tree_int_cst_lt (p->high, low))
4045 /* We have an overlap; this is an error. */
4046 *duplicate = p->code_label;
4051 /* Add this label to the chain, and succeed. */
4053 r = ggc_alloc (sizeof (struct case_node));
4056 /* If the bounds are equal, turn this into the one-value case. */
4057 if (tree_int_cst_equal (low, high))
4062 r->code_label = label;
4063 if (!dont_expand_label)
4064 expand_label (label);
4074 struct case_node *s;
4080 if (! (b = p->balance))
4081 /* Growth propagation from left side. */
4088 if ((p->left = s = r->right))
4097 if ((r->parent = s))
4105 case_stack->data.case_stmt.case_list = r;
4108 /* r->balance == +1 */
4113 struct case_node *t = r->right;
4115 if ((p->left = s = t->right))
4119 if ((r->right = s = t->left))
4133 if ((t->parent = s))
4141 case_stack->data.case_stmt.case_list = t;
4148 /* p->balance == +1; growth of left side balances the node. */
4158 if (! (b = p->balance))
4159 /* Growth propagation from right side. */
4167 if ((p->right = s = r->left))
4175 if ((r->parent = s))
4184 case_stack->data.case_stmt.case_list = r;
4188 /* r->balance == -1 */
4192 struct case_node *t = r->left;
4194 if ((p->right = s = t->left))
4199 if ((r->left = s = t->right))
4213 if ((t->parent = s))
4222 case_stack->data.case_stmt.case_list = t;
4228 /* p->balance == -1; growth of right side balances the node. */
4241 /* Maximum number of case bit tests. */
4242 #define MAX_CASE_BIT_TESTS 3
4244 /* By default, enable case bit tests on targets with ashlsi3. */
4245 #ifndef CASE_USE_BIT_TESTS
4246 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
4247 != CODE_FOR_nothing)
4251 /* A case_bit_test represents a set of case nodes that may be
4252 selected from using a bit-wise comparison. HI and LO hold
4253 the integer to be tested against, LABEL contains the label
4254 to jump to upon success and BITS counts the number of case
4255 nodes handled by this test, typically the number of bits
4258 struct case_bit_test
4266 /* Determine whether "1 << x" is relatively cheap in word_mode. */
4269 bool lshift_cheap_p (void)
4271 static bool init = false;
4272 static bool cheap = true;
4276 rtx reg = gen_rtx_REG (word_mode, 10000);
4277 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
4278 cheap = cost < COSTS_N_INSNS (3);
4285 /* Comparison function for qsort to order bit tests by decreasing
4286 number of case nodes, i.e. the node with the most cases gets
4290 case_bit_test_cmp (const void *p1, const void *p2)
4292 const struct case_bit_test *d1 = p1;
4293 const struct case_bit_test *d2 = p2;
4295 return d2->bits - d1->bits;
4298 /* Expand a switch statement by a short sequence of bit-wise
4299 comparisons. "switch(x)" is effectively converted into
4300 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
4303 INDEX_EXPR is the value being switched on, which is of
4304 type INDEX_TYPE. MINVAL is the lowest case value of in
4305 the case nodes, of INDEX_TYPE type, and RANGE is highest
4306 value minus MINVAL, also of type INDEX_TYPE. NODES is
4307 the set of case nodes, and DEFAULT_LABEL is the label to
4308 branch to should none of the cases match.
4310 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
4314 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
4315 tree range, case_node_ptr nodes, rtx default_label)
4317 struct case_bit_test test[MAX_CASE_BIT_TESTS];
4318 enum machine_mode mode;
4319 rtx expr, index, label;
4320 unsigned int i,j,lo,hi;
4321 struct case_node *n;
4325 for (n = nodes; n; n = n->right)
4327 label = label_rtx (n->code_label);
4328 for (i = 0; i < count; i++)
4329 if (same_case_target_p (label, test[i].label))
4334 if (count >= MAX_CASE_BIT_TESTS)
4338 test[i].label = label;
4345 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4346 n->low, minval)), 1);
4347 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4348 n->high, minval)), 1);
4349 for (j = lo; j <= hi; j++)
4350 if (j >= HOST_BITS_PER_WIDE_INT)
4351 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
4353 test[i].lo |= (HOST_WIDE_INT) 1 << j;
4356 qsort (test, count, sizeof(*test), case_bit_test_cmp);
4358 index_expr = fold (build (MINUS_EXPR, index_type,
4359 convert (index_type, index_expr),
4360 convert (index_type, minval)));
4361 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4363 index = protect_from_queue (index, 0);
4364 do_pending_stack_adjust ();
4366 mode = TYPE_MODE (index_type);
4367 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
4368 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
4371 index = convert_to_mode (word_mode, index, 0);
4372 index = expand_binop (word_mode, ashl_optab, const1_rtx,
4373 index, NULL_RTX, 1, OPTAB_WIDEN);
4375 for (i = 0; i < count; i++)
4377 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
4378 expr = expand_binop (word_mode, and_optab, index, expr,
4379 NULL_RTX, 1, OPTAB_WIDEN);
4380 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
4381 word_mode, 1, test[i].label);
4384 emit_jump (default_label);
4388 #define HAVE_casesi 0
4391 #ifndef HAVE_tablejump
4392 #define HAVE_tablejump 0
4395 /* Terminate a case (Pascal) or switch (C) statement
4396 in which ORIG_INDEX is the expression to be tested.
4397 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
4398 type as given in the source before any compiler conversions.
4399 Generate the code to test it and jump to the right place. */
4402 expand_end_case_type (tree orig_index, tree orig_type)
4404 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
4405 rtx default_label = 0;
4406 struct case_node *n, *m;
4407 unsigned int count, uniq;
4413 rtx before_case, end, lab;
4414 struct nesting *thiscase = case_stack;
4415 tree index_expr, index_type;
4416 bool exit_done = false;
4419 /* Don't crash due to previous errors. */
4420 if (thiscase == NULL)
4423 index_expr = thiscase->data.case_stmt.index_expr;
4424 index_type = TREE_TYPE (index_expr);
4425 unsignedp = TYPE_UNSIGNED (index_type);
4426 if (orig_type == NULL)
4427 orig_type = TREE_TYPE (orig_index);
4429 do_pending_stack_adjust ();
4431 /* This might get a spurious warning in the presence of a syntax error;
4432 it could be fixed by moving the call to check_seenlabel after the
4433 check for error_mark_node, and copying the code of check_seenlabel that
4434 deals with case_stack->data.case_stmt.line_number_status /
4435 restore_line_number_status in front of the call to end_cleanup_deferral;
4436 However, this might miss some useful warnings in the presence of
4437 non-syntax errors. */
4440 /* An ERROR_MARK occurs for various reasons including invalid data type. */
4441 if (index_type != error_mark_node)
4443 /* If we don't have a default-label, create one here,
4444 after the body of the switch. */
4445 if (thiscase->data.case_stmt.default_label == 0)
4447 thiscase->data.case_stmt.default_label
4448 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
4449 /* Share the exit label if possible. */
4450 if (thiscase->exit_label)
4452 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
4453 thiscase->exit_label);
4456 expand_label (thiscase->data.case_stmt.default_label);
4458 default_label = label_rtx (thiscase->data.case_stmt.default_label);
4460 before_case = get_last_insn ();
4462 if (thiscase->data.case_stmt.case_list
4463 && thiscase->data.case_stmt.case_list->left)
4464 thiscase->data.case_stmt.case_list
4465 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
4467 /* Simplify the case-list before we count it. */
4468 group_case_nodes (thiscase->data.case_stmt.case_list);
4469 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
4472 /* Get upper and lower bounds of case values.
4473 Also convert all the case values to the index expr's data type. */
4477 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4479 /* Check low and high label values are integers. */
4480 if (TREE_CODE (n->low) != INTEGER_CST)
4482 if (TREE_CODE (n->high) != INTEGER_CST)
4485 n->low = convert (index_type, n->low);
4486 n->high = convert (index_type, n->high);
4488 /* Count the elements and track the largest and smallest
4489 of them (treating them as signed even if they are not). */
4497 if (INT_CST_LT (n->low, minval))
4499 if (INT_CST_LT (maxval, n->high))
4502 /* A range counts double, since it requires two compares. */
4503 if (! tree_int_cst_equal (n->low, n->high))
4506 /* Count the number of unique case node targets. */
4508 lab = label_rtx (n->code_label);
4509 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
4510 if (same_case_target_p (label_rtx (m->code_label), lab))
4517 /* Compute span of values. */
4519 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
4521 end_cleanup_deferral ();
4525 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
4527 emit_jump (default_label);
4530 /* Try implementing this switch statement by a short sequence of
4531 bit-wise comparisons. However, we let the binary-tree case
4532 below handle constant index expressions. */
4533 else if (CASE_USE_BIT_TESTS
4534 && ! TREE_CONSTANT (index_expr)
4535 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
4536 && compare_tree_int (range, 0) > 0
4537 && lshift_cheap_p ()
4538 && ((uniq == 1 && count >= 3)
4539 || (uniq == 2 && count >= 5)
4540 || (uniq == 3 && count >= 6)))
4542 /* Optimize the case where all the case values fit in a
4543 word without having to subtract MINVAL. In this case,
4544 we can optimize away the subtraction. */
4545 if (compare_tree_int (minval, 0) > 0
4546 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
4548 minval = integer_zero_node;
4551 emit_case_bit_tests (index_type, index_expr, minval, range,
4552 thiscase->data.case_stmt.case_list,
4556 /* If range of values is much bigger than number of values,
4557 make a sequence of conditional branches instead of a dispatch.
4558 If the switch-index is a constant, do it this way
4559 because we can optimize it. */
4561 else if (count < case_values_threshold ()
4562 || compare_tree_int (range,
4563 (optimize_size ? 3 : 10) * count) > 0
4564 /* RANGE may be signed, and really large ranges will show up
4565 as negative numbers. */
4566 || compare_tree_int (range, 0) < 0
4567 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
4570 || TREE_CONSTANT (index_expr)
4571 /* If neither casesi or tablejump is available, we can
4572 only go this way. */
4573 || (!HAVE_casesi && !HAVE_tablejump))
4575 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4577 /* If the index is a short or char that we do not have
4578 an insn to handle comparisons directly, convert it to
4579 a full integer now, rather than letting each comparison
4580 generate the conversion. */
4582 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
4583 && ! have_insn_for (COMPARE, GET_MODE (index)))
4585 enum machine_mode wider_mode;
4586 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
4587 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
4588 if (have_insn_for (COMPARE, wider_mode))
4590 index = convert_to_mode (wider_mode, index, unsignedp);
4596 do_pending_stack_adjust ();
4598 index = protect_from_queue (index, 0);
4599 if (GET_CODE (index) == MEM)
4600 index = copy_to_reg (index);
4601 if (GET_CODE (index) == CONST_INT
4602 || TREE_CODE (index_expr) == INTEGER_CST)
4604 /* Make a tree node with the proper constant value
4605 if we don't already have one. */
4606 if (TREE_CODE (index_expr) != INTEGER_CST)
4609 = build_int_2 (INTVAL (index),
4610 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
4611 index_expr = convert (index_type, index_expr);
4614 /* For constant index expressions we need only
4615 issue an unconditional branch to the appropriate
4616 target code. The job of removing any unreachable
4617 code is left to the optimization phase if the
4618 "-O" option is specified. */
4619 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4620 if (! tree_int_cst_lt (index_expr, n->low)
4621 && ! tree_int_cst_lt (n->high, index_expr))
4625 emit_jump (label_rtx (n->code_label));
4627 emit_jump (default_label);
4631 /* If the index expression is not constant we generate
4632 a binary decision tree to select the appropriate
4633 target code. This is done as follows:
4635 The list of cases is rearranged into a binary tree,
4636 nearly optimal assuming equal probability for each case.
4638 The tree is transformed into RTL, eliminating
4639 redundant test conditions at the same time.
4641 If program flow could reach the end of the
4642 decision tree an unconditional jump to the
4643 default code is emitted. */
4646 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
4647 && estimate_case_costs (thiscase->data.case_stmt.case_list));
4648 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
4649 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
4650 default_label, index_type);
4651 emit_jump_if_reachable (default_label);
4656 table_label = gen_label_rtx ();
4657 if (! try_casesi (index_type, index_expr, minval, range,
4658 table_label, default_label))
4660 index_type = thiscase->data.case_stmt.nominal_type;
4662 /* Index jumptables from zero for suitable values of
4663 minval to avoid a subtraction. */
4665 && compare_tree_int (minval, 0) > 0
4666 && compare_tree_int (minval, 3) < 0)
4668 minval = integer_zero_node;
4672 if (! try_tablejump (index_type, index_expr, minval, range,
4673 table_label, default_label))
4677 /* Get table of labels to jump to, in order of case index. */
4679 ncases = tree_low_cst (range, 0) + 1;
4680 labelvec = alloca (ncases * sizeof (rtx));
4681 memset (labelvec, 0, ncases * sizeof (rtx));
4683 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4685 /* Compute the low and high bounds relative to the minimum
4686 value since that should fit in a HOST_WIDE_INT while the
4687 actual values may not. */
4689 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4690 n->low, minval)), 1);
4691 HOST_WIDE_INT i_high
4692 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
4693 n->high, minval)), 1);
4696 for (i = i_low; i <= i_high; i ++)
4698 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
4701 /* Fill in the gaps with the default. */
4702 for (i = 0; i < ncases; i++)
4703 if (labelvec[i] == 0)
4704 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
4706 /* Output the table. */
4707 emit_label (table_label);
4709 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
4710 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
4711 gen_rtx_LABEL_REF (Pmode, table_label),
4712 gen_rtvec_v (ncases, labelvec),
4713 const0_rtx, const0_rtx));
4715 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
4716 gen_rtvec_v (ncases, labelvec)));
4718 /* If the case insn drops through the table,
4719 after the table we must jump to the default-label.
4720 Otherwise record no drop-through after the table. */
4721 #ifdef CASE_DROPS_THROUGH
4722 emit_jump (default_label);
4728 before_case = NEXT_INSN (before_case);
4729 end = get_last_insn ();
4730 if (squeeze_notes (&before_case, &end))
4732 reorder_insns (before_case, end,
4733 thiscase->data.case_stmt.start);
4736 end_cleanup_deferral ();
4738 if (thiscase->exit_label && !exit_done)
4739 emit_label (thiscase->exit_label);
4741 POPSTACK (case_stack);
4746 /* Convert the tree NODE into a list linked by the right field, with the left
4747 field zeroed. RIGHT is used for recursion; it is a list to be placed
4748 rightmost in the resulting list. */
4750 static struct case_node *
4751 case_tree2list (struct case_node *node, struct case_node *right)
4753 struct case_node *left;
4756 right = case_tree2list (node->right, right);
4758 node->right = right;
4759 if ((left = node->left))
4762 return case_tree2list (left, node);
4768 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
4771 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
4773 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
4779 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
4780 (GET_MODE (op1) == VOIDmode
4781 ? GET_MODE (op2) : GET_MODE (op1)),
4785 /* Not all case values are encountered equally. This function
4786 uses a heuristic to weight case labels, in cases where that
4787 looks like a reasonable thing to do.
4789 Right now, all we try to guess is text, and we establish the
4792 chars above space: 16
4801 If we find any cases in the switch that are not either -1 or in the range
4802 of valid ASCII characters, or are control characters other than those
4803 commonly used with "\", don't treat this switch scanning text.
4805 Return 1 if these nodes are suitable for cost estimation, otherwise
4809 estimate_case_costs (case_node_ptr node)
4811 tree min_ascii = integer_minus_one_node;
4812 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
4816 /* If we haven't already made the cost table, make it now. Note that the
4817 lower bound of the table is -1, not zero. */
4819 if (! cost_table_initialized)
4821 cost_table_initialized = 1;
4823 for (i = 0; i < 128; i++)
4826 COST_TABLE (i) = 16;
4827 else if (ISPUNCT (i))
4829 else if (ISCNTRL (i))
4830 COST_TABLE (i) = -1;
4833 COST_TABLE (' ') = 8;
4834 COST_TABLE ('\t') = 4;
4835 COST_TABLE ('\0') = 4;
4836 COST_TABLE ('\n') = 2;
4837 COST_TABLE ('\f') = 1;
4838 COST_TABLE ('\v') = 1;
4839 COST_TABLE ('\b') = 1;
4842 /* See if all the case expressions look like text. It is text if the
4843 constant is >= -1 and the highest constant is <= 127. Do all comparisons
4844 as signed arithmetic since we don't want to ever access cost_table with a
4845 value less than -1. Also check that none of the constants in a range
4846 are strange control characters. */
4848 for (n = node; n; n = n->right)
4850 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
4853 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
4854 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
4855 if (COST_TABLE (i) < 0)
4859 /* All interesting values are within the range of interesting
4860 ASCII characters. */
4864 /* Determine whether two case labels branch to the same target. */
4867 same_case_target_p (rtx l1, rtx l2)
4875 i1 = next_real_insn (l1);
4876 i2 = next_real_insn (l2);
4880 if (i1 && simplejump_p (i1))
4882 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
4885 if (i2 && simplejump_p (i2))
4887 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
4890 /* When coming from gimple, we usually won't have emitted either
4891 the labels or the body of the switch statement. The job being
4892 done here should be done via jump threading at the tree level.
4893 Cases that go the same place should have the same label. */
4897 /* Delete nodes that branch to the default label from a list of
4898 case nodes. Eg. case 5: default: becomes just default: */
4901 strip_default_case_nodes (case_node_ptr *prev, rtx deflab)
4908 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
4915 /* Scan an ordered list of case nodes
4916 combining those with consecutive values or ranges.
4918 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
4921 group_case_nodes (case_node_ptr head)
4923 case_node_ptr node = head;
4928 case_node_ptr np = node;
4930 lab = label_rtx (node->code_label);
4932 /* Try to group the successors of NODE with NODE. */
4933 while (((np = np->right) != 0)
4934 /* Do they jump to the same place? */
4935 && same_case_target_p (label_rtx (np->code_label), lab)
4936 /* Are their ranges consecutive? */
4937 && tree_int_cst_equal (np->low,
4938 fold (build (PLUS_EXPR,
4939 TREE_TYPE (node->high),
4942 /* An overflow is not consecutive. */
4943 && tree_int_cst_lt (node->high,
4944 fold (build (PLUS_EXPR,
4945 TREE_TYPE (node->high),
4947 integer_one_node))))
4949 node->high = np->high;
4951 /* NP is the first node after NODE which can't be grouped with it.
4952 Delete the nodes in between, and move on to that node. */
4958 /* Take an ordered list of case nodes
4959 and transform them into a near optimal binary tree,
4960 on the assumption that any target code selection value is as
4961 likely as any other.
4963 The transformation is performed by splitting the ordered
4964 list into two equal sections plus a pivot. The parts are
4965 then attached to the pivot as left and right branches. Each
4966 branch is then transformed recursively. */
4969 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
4982 /* Count the number of entries on branch. Also count the ranges. */
4986 if (!tree_int_cst_equal (np->low, np->high))
4990 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
4994 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5002 /* Split this list if it is long enough for that to help. */
5007 /* Find the place in the list that bisects the list's total cost,
5008 Here I gets half the total cost. */
5013 /* Skip nodes while their cost does not reach that amount. */
5014 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5015 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5016 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5019 npp = &(*npp)->right;
5024 /* Leave this branch lopsided, but optimize left-hand
5025 side and fill in `parent' fields for right-hand side. */
5027 np->parent = parent;
5028 balance_case_nodes (&np->left, np);
5029 for (; np->right; np = np->right)
5030 np->right->parent = np;
5034 /* If there are just three nodes, split at the middle one. */
5036 npp = &(*npp)->right;
5039 /* Find the place in the list that bisects the list's total cost,
5040 where ranges count as 2.
5041 Here I gets half the total cost. */
5042 i = (i + ranges + 1) / 2;
5045 /* Skip nodes while their cost does not reach that amount. */
5046 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5051 npp = &(*npp)->right;
5056 np->parent = parent;
5059 /* Optimize each of the two split parts. */
5060 balance_case_nodes (&np->left, np);
5061 balance_case_nodes (&np->right, np);
5065 /* Else leave this branch as one level,
5066 but fill in `parent' fields. */
5068 np->parent = parent;
5069 for (; np->right; np = np->right)
5070 np->right->parent = np;
5075 /* Search the parent sections of the case node tree
5076 to see if a test for the lower bound of NODE would be redundant.
5077 INDEX_TYPE is the type of the index expression.
5079 The instructions to generate the case decision tree are
5080 output in the same order as nodes are processed so it is
5081 known that if a parent node checks the range of the current
5082 node minus one that the current node is bounded at its lower
5083 span. Thus the test would be redundant. */
5086 node_has_low_bound (case_node_ptr node, tree index_type)
5089 case_node_ptr pnode;
5091 /* If the lower bound of this node is the lowest value in the index type,
5092 we need not test it. */
5094 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5097 /* If this node has a left branch, the value at the left must be less
5098 than that at this node, so it cannot be bounded at the bottom and
5099 we need not bother testing any further. */
5104 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5105 node->low, integer_one_node));
5107 /* If the subtraction above overflowed, we can't verify anything.
5108 Otherwise, look for a parent that tests our value - 1. */
5110 if (! tree_int_cst_lt (low_minus_one, node->low))
5113 for (pnode = node->parent; pnode; pnode = pnode->parent)
5114 if (tree_int_cst_equal (low_minus_one, pnode->high))
5120 /* Search the parent sections of the case node tree
5121 to see if a test for the upper bound of NODE would be redundant.
5122 INDEX_TYPE is the type of the index expression.
5124 The instructions to generate the case decision tree are
5125 output in the same order as nodes are processed so it is
5126 known that if a parent node checks the range of the current
5127 node plus one that the current node is bounded at its upper
5128 span. Thus the test would be redundant. */
5131 node_has_high_bound (case_node_ptr node, tree index_type)
5134 case_node_ptr pnode;
5136 /* If there is no upper bound, obviously no test is needed. */
5138 if (TYPE_MAX_VALUE (index_type) == NULL)
5141 /* If the upper bound of this node is the highest value in the type
5142 of the index expression, we need not test against it. */
5144 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5147 /* If this node has a right branch, the value at the right must be greater
5148 than that at this node, so it cannot be bounded at the top and
5149 we need not bother testing any further. */
5154 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5155 node->high, integer_one_node));
5157 /* If the addition above overflowed, we can't verify anything.
5158 Otherwise, look for a parent that tests our value + 1. */
5160 if (! tree_int_cst_lt (node->high, high_plus_one))
5163 for (pnode = node->parent; pnode; pnode = pnode->parent)
5164 if (tree_int_cst_equal (high_plus_one, pnode->low))
5170 /* Search the parent sections of the
5171 case node tree to see if both tests for the upper and lower
5172 bounds of NODE would be redundant. */
5175 node_is_bounded (case_node_ptr node, tree index_type)
5177 return (node_has_low_bound (node, index_type)
5178 && node_has_high_bound (node, index_type));
5181 /* Emit an unconditional jump to LABEL unless it would be dead code. */
5184 emit_jump_if_reachable (rtx label)
5186 if (GET_CODE (get_last_insn ()) != BARRIER)
5190 /* Emit step-by-step code to select a case for the value of INDEX.
5191 The thus generated decision tree follows the form of the
5192 case-node binary tree NODE, whose nodes represent test conditions.
5193 INDEX_TYPE is the type of the index of the switch.
5195 Care is taken to prune redundant tests from the decision tree
5196 by detecting any boundary conditions already checked by
5197 emitted rtx. (See node_has_high_bound, node_has_low_bound
5198 and node_is_bounded, above.)
5200 Where the test conditions can be shown to be redundant we emit
5201 an unconditional jump to the target code. As a further
5202 optimization, the subordinates of a tree node are examined to
5203 check for bounded nodes. In this case conditional and/or
5204 unconditional jumps as a result of the boundary check for the
5205 current node are arranged to target the subordinates associated
5206 code for out of bound conditions on the current node.
5208 We can assume that when control reaches the code generated here,
5209 the index value has already been compared with the parents
5210 of this node, and determined to be on the same side of each parent
5211 as this node is. Thus, if this node tests for the value 51,
5212 and a parent tested for 52, we don't need to consider
5213 the possibility of a value greater than 51. If another parent
5214 tests for the value 50, then this node need not test anything. */
5217 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
5220 /* If INDEX has an unsigned type, we must make unsigned branches. */
5221 int unsignedp = TYPE_UNSIGNED (index_type);
5222 enum machine_mode mode = GET_MODE (index);
5223 enum machine_mode imode = TYPE_MODE (index_type);
5225 /* See if our parents have already tested everything for us.
5226 If they have, emit an unconditional jump for this node. */
5227 if (node_is_bounded (node, index_type))
5228 emit_jump (label_rtx (node->code_label));
5230 else if (tree_int_cst_equal (node->low, node->high))
5232 /* Node is single valued. First see if the index expression matches
5233 this node and then check our children, if any. */
5235 do_jump_if_equal (index,
5236 convert_modes (mode, imode,
5237 expand_expr (node->low, NULL_RTX,
5240 label_rtx (node->code_label), unsignedp);
5242 if (node->right != 0 && node->left != 0)
5244 /* This node has children on both sides.
5245 Dispatch to one side or the other
5246 by comparing the index value with this node's value.
5247 If one subtree is bounded, check that one first,
5248 so we can avoid real branches in the tree. */
5250 if (node_is_bounded (node->right, index_type))
5252 emit_cmp_and_jump_insns (index,
5255 expand_expr (node->high, NULL_RTX,
5258 GT, NULL_RTX, mode, unsignedp,
5259 label_rtx (node->right->code_label));
5260 emit_case_nodes (index, node->left, default_label, index_type);
5263 else if (node_is_bounded (node->left, index_type))
5265 emit_cmp_and_jump_insns (index,
5268 expand_expr (node->high, NULL_RTX,
5271 LT, NULL_RTX, mode, unsignedp,
5272 label_rtx (node->left->code_label));
5273 emit_case_nodes (index, node->right, default_label, index_type);
5276 /* If both children are single-valued cases with no
5277 children, finish up all the work. This way, we can save
5278 one ordered comparison. */
5279 else if (tree_int_cst_equal (node->right->low, node->right->high)
5280 && node->right->left == 0
5281 && node->right->right == 0
5282 && tree_int_cst_equal (node->left->low, node->left->high)
5283 && node->left->left == 0
5284 && node->left->right == 0)
5286 /* Neither node is bounded. First distinguish the two sides;
5287 then emit the code for one side at a time. */
5289 /* See if the value matches what the right hand side
5291 do_jump_if_equal (index,
5292 convert_modes (mode, imode,
5293 expand_expr (node->right->low,
5297 label_rtx (node->right->code_label),
5300 /* See if the value matches what the left hand side
5302 do_jump_if_equal (index,
5303 convert_modes (mode, imode,
5304 expand_expr (node->left->low,
5308 label_rtx (node->left->code_label),
5314 /* Neither node is bounded. First distinguish the two sides;
5315 then emit the code for one side at a time. */
5317 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5319 /* See if the value is on the right. */
5320 emit_cmp_and_jump_insns (index,
5323 expand_expr (node->high, NULL_RTX,
5326 GT, NULL_RTX, mode, unsignedp,
5327 label_rtx (test_label));
5329 /* Value must be on the left.
5330 Handle the left-hand subtree. */
5331 emit_case_nodes (index, node->left, default_label, index_type);
5332 /* If left-hand subtree does nothing,
5334 emit_jump_if_reachable (default_label);
5336 /* Code branches here for the right-hand subtree. */
5337 expand_label (test_label);
5338 emit_case_nodes (index, node->right, default_label, index_type);
5342 else if (node->right != 0 && node->left == 0)
5344 /* Here we have a right child but no left so we issue conditional
5345 branch to default and process the right child.
5347 Omit the conditional branch to default if we it avoid only one
5348 right child; it costs too much space to save so little time. */
5350 if (node->right->right || node->right->left
5351 || !tree_int_cst_equal (node->right->low, node->right->high))
5353 if (!node_has_low_bound (node, index_type))
5355 emit_cmp_and_jump_insns (index,
5358 expand_expr (node->high, NULL_RTX,
5361 LT, NULL_RTX, mode, unsignedp,
5365 emit_case_nodes (index, node->right, default_label, index_type);
5368 /* We cannot process node->right normally
5369 since we haven't ruled out the numbers less than
5370 this node's value. So handle node->right explicitly. */
5371 do_jump_if_equal (index,
5374 expand_expr (node->right->low, NULL_RTX,
5377 label_rtx (node->right->code_label), unsignedp);
5380 else if (node->right == 0 && node->left != 0)
5382 /* Just one subtree, on the left. */
5383 if (node->left->left || node->left->right
5384 || !tree_int_cst_equal (node->left->low, node->left->high))
5386 if (!node_has_high_bound (node, index_type))
5388 emit_cmp_and_jump_insns (index,
5391 expand_expr (node->high, NULL_RTX,
5394 GT, NULL_RTX, mode, unsignedp,
5398 emit_case_nodes (index, node->left, default_label, index_type);
5401 /* We cannot process node->left normally
5402 since we haven't ruled out the numbers less than
5403 this node's value. So handle node->left explicitly. */
5404 do_jump_if_equal (index,
5407 expand_expr (node->left->low, NULL_RTX,
5410 label_rtx (node->left->code_label), unsignedp);
5415 /* Node is a range. These cases are very similar to those for a single
5416 value, except that we do not start by testing whether this node
5417 is the one to branch to. */
5419 if (node->right != 0 && node->left != 0)
5421 /* Node has subtrees on both sides.
5422 If the right-hand subtree is bounded,
5423 test for it first, since we can go straight there.
5424 Otherwise, we need to make a branch in the control structure,
5425 then handle the two subtrees. */
5426 tree test_label = 0;
5428 if (node_is_bounded (node->right, index_type))
5429 /* Right hand node is fully bounded so we can eliminate any
5430 testing and branch directly to the target code. */
5431 emit_cmp_and_jump_insns (index,
5434 expand_expr (node->high, NULL_RTX,
5437 GT, NULL_RTX, mode, unsignedp,
5438 label_rtx (node->right->code_label));
5441 /* Right hand node requires testing.
5442 Branch to a label where we will handle it later. */
5444 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5445 emit_cmp_and_jump_insns (index,
5448 expand_expr (node->high, NULL_RTX,
5451 GT, NULL_RTX, mode, unsignedp,
5452 label_rtx (test_label));
5455 /* Value belongs to this node or to the left-hand subtree. */
5457 emit_cmp_and_jump_insns (index,
5460 expand_expr (node->low, NULL_RTX,
5463 GE, NULL_RTX, mode, unsignedp,
5464 label_rtx (node->code_label));
5466 /* Handle the left-hand subtree. */
5467 emit_case_nodes (index, node->left, default_label, index_type);
5469 /* If right node had to be handled later, do that now. */
5473 /* If the left-hand subtree fell through,
5474 don't let it fall into the right-hand subtree. */
5475 emit_jump_if_reachable (default_label);
5477 expand_label (test_label);
5478 emit_case_nodes (index, node->right, default_label, index_type);
5482 else if (node->right != 0 && node->left == 0)
5484 /* Deal with values to the left of this node,
5485 if they are possible. */
5486 if (!node_has_low_bound (node, index_type))
5488 emit_cmp_and_jump_insns (index,
5491 expand_expr (node->low, NULL_RTX,
5494 LT, NULL_RTX, mode, unsignedp,
5498 /* Value belongs to this node or to the right-hand subtree. */
5500 emit_cmp_and_jump_insns (index,
5503 expand_expr (node->high, NULL_RTX,
5506 LE, NULL_RTX, mode, unsignedp,
5507 label_rtx (node->code_label));
5509 emit_case_nodes (index, node->right, default_label, index_type);
5512 else if (node->right == 0 && node->left != 0)
5514 /* Deal with values to the right of this node,
5515 if they are possible. */
5516 if (!node_has_high_bound (node, index_type))
5518 emit_cmp_and_jump_insns (index,
5521 expand_expr (node->high, NULL_RTX,
5524 GT, NULL_RTX, mode, unsignedp,
5528 /* Value belongs to this node or to the left-hand subtree. */
5530 emit_cmp_and_jump_insns (index,
5533 expand_expr (node->low, NULL_RTX,
5536 GE, NULL_RTX, mode, unsignedp,
5537 label_rtx (node->code_label));
5539 emit_case_nodes (index, node->left, default_label, index_type);
5544 /* Node has no children so we check low and high bounds to remove
5545 redundant tests. Only one of the bounds can exist,
5546 since otherwise this node is bounded--a case tested already. */
5547 int high_bound = node_has_high_bound (node, index_type);
5548 int low_bound = node_has_low_bound (node, index_type);
5550 if (!high_bound && low_bound)
5552 emit_cmp_and_jump_insns (index,
5555 expand_expr (node->high, NULL_RTX,
5558 GT, NULL_RTX, mode, unsignedp,
5562 else if (!low_bound && high_bound)
5564 emit_cmp_and_jump_insns (index,
5567 expand_expr (node->low, NULL_RTX,
5570 LT, NULL_RTX, mode, unsignedp,
5573 else if (!low_bound && !high_bound)
5575 /* Widen LOW and HIGH to the same width as INDEX. */
5576 tree type = lang_hooks.types.type_for_mode (mode, unsignedp);
5577 tree low = build1 (CONVERT_EXPR, type, node->low);
5578 tree high = build1 (CONVERT_EXPR, type, node->high);
5579 rtx low_rtx, new_index, new_bound;
5581 /* Instead of doing two branches, emit one unsigned branch for
5582 (index-low) > (high-low). */
5583 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
5584 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
5585 NULL_RTX, unsignedp,
5587 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
5591 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
5592 mode, 1, default_label);
5595 emit_jump (label_rtx (node->code_label));
5600 #include "gt-stmt.h"