1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002 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. */
45 #include "insn-config.h"
48 #include "hard-reg-set.h"
55 #include "langhooks.h"
58 /* Assume that case vectors are not pc-relative. */
59 #ifndef CASE_VECTOR_PC_RELATIVE
60 #define CASE_VECTOR_PC_RELATIVE 0
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 `loop_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;
151 /* For conds (if-then and if-then-else statements). */
154 /* Label for the end of the if construct.
155 There is none if EXITFLAG was not set
156 and no `else' has been seen yet. */
158 /* Label for the end of this alternative.
159 This may be the end of the if or the next else/elseif. */
161 } GTY ((tag ("COND_NESTING"))) cond;
165 /* Label at the top of the loop; place to loop back to. */
167 /* Label at the end of the whole construct. */
169 /* Label before a jump that branches to the end of the whole
170 construct. This is where destructors go if any. */
172 /* Label for `continue' statement to jump to;
173 this is in front of the stepper of the loop. */
175 } GTY ((tag ("LOOP_NESTING"))) loop;
176 /* For variable binding contours. */
179 /* Sequence number of this binding contour within the function,
180 in order of entry. */
181 int block_start_count;
182 /* Nonzero => value to restore stack to on exit. */
184 /* The NOTE that starts this contour.
185 Used by expand_goto to check whether the destination
186 is within each contour or not. */
188 /* Innermost containing binding contour that has a stack level. */
189 struct nesting *innermost_stack_block;
190 /* List of cleanups to be run on exit from this contour.
191 This is a list of expressions to be evaluated.
192 The TREE_PURPOSE of each link is the ..._DECL node
193 which the cleanup pertains to. */
195 /* List of cleanup-lists of blocks containing this block,
196 as they were at the locus where this block appears.
197 There is an element for each containing block,
198 ordered innermost containing block first.
199 The tail of this list can be 0,
200 if all remaining elements would be empty lists.
201 The element's TREE_VALUE is the cleanup-list of that block,
202 which may be null. */
204 /* Chain of labels defined inside this binding contour.
205 For contours that have stack levels or cleanups. */
206 struct label_chain *label_chain;
207 /* Number of function calls seen, as of start of this block. */
208 int n_function_calls;
209 /* Nonzero if this is associated with an EH region. */
210 int exception_region;
211 /* The saved target_temp_slot_level from our outer block.
212 We may reset target_temp_slot_level to be the level of
213 this block, if that is done, target_temp_slot_level
214 reverts to the saved target_temp_slot_level at the very
216 int block_target_temp_slot_level;
217 /* True if we are currently emitting insns in an area of
218 output code that is controlled by a conditional
219 expression. This is used by the cleanup handling code to
220 generate conditional cleanup actions. */
221 int conditional_code;
222 /* A place to move the start of the exception region for any
223 of the conditional cleanups, must be at the end or after
224 the start of the last unconditional cleanup, and before any
225 conditional branch points. */
226 rtx last_unconditional_cleanup;
227 } GTY ((tag ("BLOCK_NESTING"))) block;
228 /* For switch (C) or case (Pascal) statements,
229 and also for dummies (see `expand_start_case_dummy'). */
232 /* The insn after which the case dispatch should finally
233 be emitted. Zero for a dummy. */
235 /* A list of case labels; it is first built as an AVL tree.
236 During expand_end_case, this is converted to a list, and may be
237 rearranged into a nearly balanced binary tree. */
238 struct case_node *case_list;
239 /* Label to jump to if no case matches. */
241 /* The expression to be dispatched on. */
243 /* Type that INDEX_EXPR should be converted to. */
245 /* Name of this kind of statement, for warnings. */
246 const char *printname;
247 /* Used to save no_line_numbers till we see the first case label.
248 We set this to -1 when we see the first case label in this
250 int line_number_status;
251 } GTY ((tag ("CASE_NESTING"))) case_stmt;
252 } GTY ((desc ("%1.desc"))) data;
255 /* Allocate and return a new `struct nesting'. */
257 #define ALLOC_NESTING() \
258 (struct nesting *) ggc_alloc (sizeof (struct nesting))
260 /* Pop the nesting stack element by element until we pop off
261 the element which is at the top of STACK.
262 Update all the other stacks, popping off elements from them
263 as we pop them from nesting_stack. */
265 #define POPSTACK(STACK) \
266 do { struct nesting *target = STACK; \
267 struct nesting *this; \
268 do { this = nesting_stack; \
269 if (loop_stack == this) \
270 loop_stack = loop_stack->next; \
271 if (cond_stack == this) \
272 cond_stack = cond_stack->next; \
273 if (block_stack == this) \
274 block_stack = block_stack->next; \
275 if (stack_block_stack == this) \
276 stack_block_stack = stack_block_stack->next; \
277 if (case_stack == this) \
278 case_stack = case_stack->next; \
279 nesting_depth = nesting_stack->depth - 1; \
280 nesting_stack = this->all; } \
281 while (this != target); } while (0)
283 /* In some cases it is impossible to generate code for a forward goto
284 until the label definition is seen. This happens when it may be necessary
285 for the goto to reset the stack pointer: we don't yet know how to do that.
286 So expand_goto puts an entry on this fixup list.
287 Each time a binding contour that resets the stack is exited,
289 If the target label has now been defined, we can insert the proper code. */
291 struct goto_fixup GTY(())
293 /* Points to following fixup. */
294 struct goto_fixup *next;
295 /* Points to the insn before the jump insn.
296 If more code must be inserted, it goes after this insn. */
298 /* The LABEL_DECL that this jump is jumping to, or 0
299 for break, continue or return. */
301 /* The BLOCK for the place where this goto was found. */
303 /* The CODE_LABEL rtx that this is jumping to. */
305 /* Number of binding contours started in current function
306 before the label reference. */
307 int block_start_count;
308 /* The outermost stack level that should be restored for this jump.
309 Each time a binding contour that resets the stack is exited,
310 if the target label is *not* yet defined, this slot is updated. */
312 /* List of lists of cleanup expressions to be run by this goto.
313 There is one element for each block that this goto is within.
314 The tail of this list can be 0,
315 if all remaining elements would be empty.
316 The TREE_VALUE contains the cleanup list of that block as of the
317 time this goto was seen.
318 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
319 tree cleanup_list_list;
322 /* Within any binding contour that must restore a stack level,
323 all labels are recorded with a chain of these structures. */
325 struct label_chain GTY(())
327 /* Points to following fixup. */
328 struct label_chain *next;
332 struct stmt_status GTY(())
334 /* Chain of all pending binding contours. */
335 struct nesting * x_block_stack;
337 /* If any new stacks are added here, add them to POPSTACKS too. */
339 /* Chain of all pending binding contours that restore stack levels
341 struct nesting * x_stack_block_stack;
343 /* Chain of all pending conditional statements. */
344 struct nesting * x_cond_stack;
346 /* Chain of all pending loops. */
347 struct nesting * x_loop_stack;
349 /* Chain of all pending case or switch statements. */
350 struct nesting * x_case_stack;
352 /* Separate chain including all of the above,
353 chained through the `all' field. */
354 struct nesting * x_nesting_stack;
356 /* Number of entries on nesting_stack now. */
359 /* Number of binding contours started so far in this function. */
360 int x_block_start_count;
362 /* Each time we expand an expression-statement,
363 record the expr's type and its RTL value here. */
364 tree x_last_expr_type;
365 rtx x_last_expr_value;
367 /* Nonzero if within a ({...}) grouping, in which case we must
368 always compute a value for each expr-stmt in case it is the last one. */
369 int x_expr_stmts_for_value;
371 /* Filename and line number of last line-number note,
372 whether we actually emitted it or not. */
373 const char *x_emit_filename;
376 struct goto_fixup *x_goto_fixup_chain;
379 #define block_stack (cfun->stmt->x_block_stack)
380 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
381 #define cond_stack (cfun->stmt->x_cond_stack)
382 #define loop_stack (cfun->stmt->x_loop_stack)
383 #define case_stack (cfun->stmt->x_case_stack)
384 #define nesting_stack (cfun->stmt->x_nesting_stack)
385 #define nesting_depth (cfun->stmt->x_nesting_depth)
386 #define current_block_start_count (cfun->stmt->x_block_start_count)
387 #define last_expr_type (cfun->stmt->x_last_expr_type)
388 #define last_expr_value (cfun->stmt->x_last_expr_value)
389 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
390 #define emit_filename (cfun->stmt->x_emit_filename)
391 #define emit_lineno (cfun->stmt->x_emit_lineno)
392 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
394 /* Non-zero if we are using EH to handle cleanups. */
395 static int using_eh_for_cleanups_p = 0;
397 static int n_occurrences PARAMS ((int, const char *));
398 static bool parse_input_constraint PARAMS ((const char **, int, int, int,
399 int, const char * const *,
401 static bool decl_conflicts_with_clobbers_p PARAMS ((tree, const HARD_REG_SET));
402 static void expand_goto_internal PARAMS ((tree, rtx, rtx));
403 static int expand_fixup PARAMS ((tree, rtx, rtx));
404 static rtx expand_nl_handler_label PARAMS ((rtx, rtx));
405 static void expand_nl_goto_receiver PARAMS ((void));
406 static void expand_nl_goto_receivers PARAMS ((struct nesting *));
407 static void fixup_gotos PARAMS ((struct nesting *, rtx, tree,
409 static bool check_operand_nalternatives PARAMS ((tree, tree));
410 static bool check_unique_operand_names PARAMS ((tree, tree));
411 static tree resolve_operand_names PARAMS ((tree, tree, tree,
413 static char *resolve_operand_name_1 PARAMS ((char *, tree, tree));
414 static void expand_null_return_1 PARAMS ((rtx));
415 static enum br_predictor return_prediction PARAMS ((rtx));
416 static void expand_value_return PARAMS ((rtx));
417 static int tail_recursion_args PARAMS ((tree, tree));
418 static void expand_cleanups PARAMS ((tree, tree, int, int));
419 static void check_seenlabel PARAMS ((void));
420 static void do_jump_if_equal PARAMS ((rtx, rtx, rtx, int));
421 static int estimate_case_costs PARAMS ((case_node_ptr));
422 static void group_case_nodes PARAMS ((case_node_ptr));
423 static void balance_case_nodes PARAMS ((case_node_ptr *,
425 static int node_has_low_bound PARAMS ((case_node_ptr, tree));
426 static int node_has_high_bound PARAMS ((case_node_ptr, tree));
427 static int node_is_bounded PARAMS ((case_node_ptr, tree));
428 static void emit_jump_if_reachable PARAMS ((rtx));
429 static void emit_case_nodes PARAMS ((rtx, case_node_ptr, rtx, tree));
430 static struct case_node *case_tree2list PARAMS ((case_node *, case_node *));
433 using_eh_for_cleanups ()
435 using_eh_for_cleanups_p = 1;
439 init_stmt_for_function ()
441 cfun->stmt = ((struct stmt_status *)ggc_alloc (sizeof (struct stmt_status)));
443 /* We are not currently within any block, conditional, loop or case. */
445 stack_block_stack = 0;
452 current_block_start_count = 0;
454 /* No gotos have been expanded yet. */
455 goto_fixup_chain = 0;
457 /* We are not processing a ({...}) grouping. */
458 expr_stmts_for_value = 0;
462 /* Return nonzero if anything is pushed on the loop, condition, or case
467 return cond_stack || loop_stack || case_stack;
470 /* Record the current file and line. Called from emit_line_note. */
472 set_file_and_line_for_stmt (file, line)
476 /* If we're outputting an inline function, and we add a line note,
477 there may be no CFUN->STMT information. So, there's no need to
481 emit_filename = file;
486 /* Emit a no-op instruction. */
493 last_insn = get_last_insn ();
495 && (GET_CODE (last_insn) == CODE_LABEL
496 || (GET_CODE (last_insn) == NOTE
497 && prev_real_insn (last_insn) == 0)))
498 emit_insn (gen_nop ());
501 /* Return the rtx-label that corresponds to a LABEL_DECL,
502 creating it if necessary. */
508 if (TREE_CODE (label) != LABEL_DECL)
511 if (!DECL_RTL_SET_P (label))
512 SET_DECL_RTL (label, gen_label_rtx ());
514 return DECL_RTL (label);
518 /* Add an unconditional jump to LABEL as the next sequential instruction. */
524 do_pending_stack_adjust ();
525 emit_jump_insn (gen_jump (label));
529 /* Emit code to jump to the address
530 specified by the pointer expression EXP. */
533 expand_computed_goto (exp)
536 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
538 #ifdef POINTERS_EXTEND_UNSIGNED
539 if (GET_MODE (x) != Pmode)
540 x = convert_memory_address (Pmode, x);
544 do_pending_stack_adjust ();
545 emit_indirect_jump (x);
547 current_function_has_computed_jump = 1;
550 /* Handle goto statements and the labels that they can go to. */
552 /* Specify the location in the RTL code of a label LABEL,
553 which is a LABEL_DECL tree node.
555 This is used for the kind of label that the user can jump to with a
556 goto statement, and for alternatives of a switch or case statement.
557 RTL labels generated for loops and conditionals don't go through here;
558 they are generated directly at the RTL level, by other functions below.
560 Note that this has nothing to do with defining label *names*.
561 Languages vary in how they do that and what that even means. */
567 struct label_chain *p;
569 do_pending_stack_adjust ();
570 emit_label (label_rtx (label));
571 if (DECL_NAME (label))
572 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
574 if (stack_block_stack != 0)
576 p = (struct label_chain *) ggc_alloc (sizeof (struct label_chain));
577 p->next = stack_block_stack->data.block.label_chain;
578 stack_block_stack->data.block.label_chain = p;
583 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
584 from nested functions. */
587 declare_nonlocal_label (label)
590 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
592 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
593 LABEL_PRESERVE_P (label_rtx (label)) = 1;
594 if (nonlocal_goto_handler_slots == 0)
596 emit_stack_save (SAVE_NONLOCAL,
597 &nonlocal_goto_stack_level,
598 PREV_INSN (tail_recursion_reentry));
600 nonlocal_goto_handler_slots
601 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
604 /* Generate RTL code for a `goto' statement with target label LABEL.
605 LABEL should be a LABEL_DECL tree node that was or will later be
606 defined with `expand_label'. */
614 /* Check for a nonlocal goto to a containing function. */
615 context = decl_function_context (label);
616 if (context != 0 && context != current_function_decl)
618 struct function *p = find_function_data (context);
619 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
620 rtx handler_slot, static_chain, save_area, insn;
623 /* Find the corresponding handler slot for this label. */
624 handler_slot = p->x_nonlocal_goto_handler_slots;
625 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
626 link = TREE_CHAIN (link))
627 handler_slot = XEXP (handler_slot, 1);
628 handler_slot = XEXP (handler_slot, 0);
630 p->has_nonlocal_label = 1;
631 current_function_has_nonlocal_goto = 1;
632 LABEL_REF_NONLOCAL_P (label_ref) = 1;
634 /* Copy the rtl for the slots so that they won't be shared in
635 case the virtual stack vars register gets instantiated differently
636 in the parent than in the child. */
638 static_chain = copy_to_reg (lookup_static_chain (label));
640 /* Get addr of containing function's current nonlocal goto handler,
641 which will do any cleanups and then jump to the label. */
642 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
643 virtual_stack_vars_rtx,
646 /* Get addr of containing function's nonlocal save area. */
647 save_area = p->x_nonlocal_goto_stack_level;
649 save_area = replace_rtx (copy_rtx (save_area),
650 virtual_stack_vars_rtx, static_chain);
652 #if HAVE_nonlocal_goto
653 if (HAVE_nonlocal_goto)
654 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
655 save_area, label_ref));
659 /* Restore frame pointer for containing function.
660 This sets the actual hard register used for the frame pointer
661 to the location of the function's incoming static chain info.
662 The non-local goto handler will then adjust it to contain the
663 proper value and reload the argument pointer, if needed. */
664 emit_move_insn (hard_frame_pointer_rtx, static_chain);
665 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
667 /* USE of hard_frame_pointer_rtx added for consistency;
668 not clear if really needed. */
669 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
670 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
671 emit_indirect_jump (handler_slot);
674 /* Search backwards to the jump insn and mark it as a
676 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
678 if (GET_CODE (insn) == JUMP_INSN)
680 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
681 const0_rtx, REG_NOTES (insn));
684 else if (GET_CODE (insn) == CALL_INSN)
689 expand_goto_internal (label, label_rtx (label), NULL_RTX);
692 /* Generate RTL code for a `goto' statement with target label BODY.
693 LABEL should be a LABEL_REF.
694 LAST_INSN, if non-0, is the rtx we should consider as the last
695 insn emitted (for the purposes of cleaning up a return). */
698 expand_goto_internal (body, label, last_insn)
703 struct nesting *block;
706 if (GET_CODE (label) != CODE_LABEL)
709 /* If label has already been defined, we can tell now
710 whether and how we must alter the stack level. */
712 if (PREV_INSN (label) != 0)
714 /* Find the innermost pending block that contains the label.
715 (Check containment by comparing insn-uids.)
716 Then restore the outermost stack level within that block,
717 and do cleanups of all blocks contained in it. */
718 for (block = block_stack; block; block = block->next)
720 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
722 if (block->data.block.stack_level != 0)
723 stack_level = block->data.block.stack_level;
724 /* Execute the cleanups for blocks we are exiting. */
725 if (block->data.block.cleanups != 0)
727 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
728 do_pending_stack_adjust ();
734 /* Ensure stack adjust isn't done by emit_jump, as this
735 would clobber the stack pointer. This one should be
736 deleted as dead by flow. */
737 clear_pending_stack_adjust ();
738 do_pending_stack_adjust ();
740 /* Don't do this adjust if it's to the end label and this function
741 is to return with a depressed stack pointer. */
742 if (label == return_label
743 && (((TREE_CODE (TREE_TYPE (current_function_decl))
745 && (TYPE_RETURNS_STACK_DEPRESSED
746 (TREE_TYPE (current_function_decl))))))
749 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
752 if (body != 0 && DECL_TOO_LATE (body))
753 error ("jump to `%s' invalidly jumps into binding contour",
754 IDENTIFIER_POINTER (DECL_NAME (body)));
756 /* Label not yet defined: may need to put this goto
757 on the fixup list. */
758 else if (! expand_fixup (body, label, last_insn))
760 /* No fixup needed. Record that the label is the target
761 of at least one goto that has no fixup. */
763 TREE_ADDRESSABLE (body) = 1;
769 /* Generate if necessary a fixup for a goto
770 whose target label in tree structure (if any) is TREE_LABEL
771 and whose target in rtl is RTL_LABEL.
773 If LAST_INSN is nonzero, we pretend that the jump appears
774 after insn LAST_INSN instead of at the current point in the insn stream.
776 The fixup will be used later to insert insns just before the goto.
777 Those insns will restore the stack level as appropriate for the
778 target label, and will (in the case of C++) also invoke any object
779 destructors which have to be invoked when we exit the scopes which
780 are exited by the goto.
782 Value is nonzero if a fixup is made. */
785 expand_fixup (tree_label, rtl_label, last_insn)
790 struct nesting *block, *end_block;
792 /* See if we can recognize which block the label will be output in.
793 This is possible in some very common cases.
794 If we succeed, set END_BLOCK to that block.
795 Otherwise, set it to 0. */
798 && (rtl_label == cond_stack->data.cond.endif_label
799 || rtl_label == cond_stack->data.cond.next_label))
800 end_block = cond_stack;
801 /* If we are in a loop, recognize certain labels which
802 are likely targets. This reduces the number of fixups
803 we need to create. */
805 && (rtl_label == loop_stack->data.loop.start_label
806 || rtl_label == loop_stack->data.loop.end_label
807 || rtl_label == loop_stack->data.loop.continue_label))
808 end_block = loop_stack;
812 /* Now set END_BLOCK to the binding level to which we will return. */
816 struct nesting *next_block = end_block->all;
819 /* First see if the END_BLOCK is inside the innermost binding level.
820 If so, then no cleanups or stack levels are relevant. */
821 while (next_block && next_block != block)
822 next_block = next_block->all;
827 /* Otherwise, set END_BLOCK to the innermost binding level
828 which is outside the relevant control-structure nesting. */
829 next_block = block_stack->next;
830 for (block = block_stack; block != end_block; block = block->all)
831 if (block == next_block)
832 next_block = next_block->next;
833 end_block = next_block;
836 /* Does any containing block have a stack level or cleanups?
837 If not, no fixup is needed, and that is the normal case
838 (the only case, for standard C). */
839 for (block = block_stack; block != end_block; block = block->next)
840 if (block->data.block.stack_level != 0
841 || block->data.block.cleanups != 0)
844 if (block != end_block)
846 /* Ok, a fixup is needed. Add a fixup to the list of such. */
847 struct goto_fixup *fixup
848 = (struct goto_fixup *) ggc_alloc (sizeof (struct goto_fixup));
849 /* In case an old stack level is restored, make sure that comes
850 after any pending stack adjust. */
851 /* ?? If the fixup isn't to come at the present position,
852 doing the stack adjust here isn't useful. Doing it with our
853 settings at that location isn't useful either. Let's hope
856 do_pending_stack_adjust ();
857 fixup->target = tree_label;
858 fixup->target_rtl = rtl_label;
860 /* Create a BLOCK node and a corresponding matched set of
861 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
862 this point. The notes will encapsulate any and all fixup
863 code which we might later insert at this point in the insn
864 stream. Also, the BLOCK node will be the parent (i.e. the
865 `SUPERBLOCK') of any other BLOCK nodes which we might create
866 later on when we are expanding the fixup code.
868 Note that optimization passes (including expand_end_loop)
869 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
873 rtx original_before_jump
874 = last_insn ? last_insn : get_last_insn ();
879 block = make_node (BLOCK);
880 TREE_USED (block) = 1;
882 if (!cfun->x_whole_function_mode_p)
883 (*lang_hooks.decls.insert_block) (block);
887 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
888 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
893 start = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
894 if (cfun->x_whole_function_mode_p)
895 NOTE_BLOCK (start) = block;
896 fixup->before_jump = emit_note (NULL, NOTE_INSN_DELETED);
897 end = emit_note (NULL, NOTE_INSN_BLOCK_END);
898 if (cfun->x_whole_function_mode_p)
899 NOTE_BLOCK (end) = block;
900 fixup->context = block;
902 emit_insn_after (start, original_before_jump);
905 fixup->block_start_count = current_block_start_count;
906 fixup->stack_level = 0;
907 fixup->cleanup_list_list
908 = ((block->data.block.outer_cleanups
909 || block->data.block.cleanups)
910 ? tree_cons (NULL_TREE, block->data.block.cleanups,
911 block->data.block.outer_cleanups)
913 fixup->next = goto_fixup_chain;
914 goto_fixup_chain = fixup;
920 /* Expand any needed fixups in the outputmost binding level of the
921 function. FIRST_INSN is the first insn in the function. */
924 expand_fixups (first_insn)
927 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
930 /* When exiting a binding contour, process all pending gotos requiring fixups.
931 THISBLOCK is the structure that describes the block being exited.
932 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
933 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
934 FIRST_INSN is the insn that began this contour.
936 Gotos that jump out of this contour must restore the
937 stack level and do the cleanups before actually jumping.
939 DONT_JUMP_IN nonzero means report error there is a jump into this
940 contour from before the beginning of the contour.
941 This is also done if STACK_LEVEL is nonzero. */
944 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
945 struct nesting *thisblock;
951 struct goto_fixup *f, *prev;
953 /* F is the fixup we are considering; PREV is the previous one. */
954 /* We run this loop in two passes so that cleanups of exited blocks
955 are run first, and blocks that are exited are marked so
958 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
960 /* Test for a fixup that is inactive because it is already handled. */
961 if (f->before_jump == 0)
963 /* Delete inactive fixup from the chain, if that is easy to do. */
965 prev->next = f->next;
967 /* Has this fixup's target label been defined?
968 If so, we can finalize it. */
969 else if (PREV_INSN (f->target_rtl) != 0)
973 /* If this fixup jumped into this contour from before the beginning
974 of this contour, report an error. This code used to use
975 the first non-label insn after f->target_rtl, but that's
976 wrong since such can be added, by things like put_var_into_stack
977 and have INSN_UIDs that are out of the range of the block. */
978 /* ??? Bug: this does not detect jumping in through intermediate
979 blocks that have stack levels or cleanups.
980 It detects only a problem with the innermost block
983 && (dont_jump_in || stack_level || cleanup_list)
984 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
985 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
986 && ! DECL_ERROR_ISSUED (f->target))
988 error_with_decl (f->target,
989 "label `%s' used before containing binding contour");
990 /* Prevent multiple errors for one label. */
991 DECL_ERROR_ISSUED (f->target) = 1;
994 /* We will expand the cleanups into a sequence of their own and
995 then later on we will attach this new sequence to the insn
996 stream just ahead of the actual jump insn. */
1000 /* Temporarily restore the lexical context where we will
1001 logically be inserting the fixup code. We do this for the
1002 sake of getting the debugging information right. */
1004 (*lang_hooks.decls.pushlevel) (0);
1005 (*lang_hooks.decls.set_block) (f->context);
1007 /* Expand the cleanups for blocks this jump exits. */
1008 if (f->cleanup_list_list)
1011 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1012 /* Marked elements correspond to blocks that have been closed.
1013 Do their cleanups. */
1014 if (TREE_ADDRESSABLE (lists)
1015 && TREE_VALUE (lists) != 0)
1017 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1018 /* Pop any pushes done in the cleanups,
1019 in case function is about to return. */
1020 do_pending_stack_adjust ();
1024 /* Restore stack level for the biggest contour that this
1025 jump jumps out of. */
1027 && ! (f->target_rtl == return_label
1028 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1030 && (TYPE_RETURNS_STACK_DEPRESSED
1031 (TREE_TYPE (current_function_decl))))))
1032 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1034 /* Finish up the sequence containing the insns which implement the
1035 necessary cleanups, and then attach that whole sequence to the
1036 insn stream just ahead of the actual jump insn. Attaching it
1037 at that point insures that any cleanups which are in fact
1038 implicit C++ object destructions (which must be executed upon
1039 leaving the block) appear (to the debugger) to be taking place
1040 in an area of the generated code where the object(s) being
1041 destructed are still "in scope". */
1043 cleanup_insns = get_insns ();
1044 (*lang_hooks.decls.poplevel) (1, 0, 0);
1047 emit_insn_after (cleanup_insns, f->before_jump);
1053 /* For any still-undefined labels, do the cleanups for this block now.
1054 We must do this now since items in the cleanup list may go out
1055 of scope when the block ends. */
1056 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1057 if (f->before_jump != 0
1058 && PREV_INSN (f->target_rtl) == 0
1059 /* Label has still not appeared. If we are exiting a block with
1060 a stack level to restore, that started before the fixup,
1061 mark this stack level as needing restoration
1062 when the fixup is later finalized. */
1064 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1065 means the label is undefined. That's erroneous, but possible. */
1066 && (thisblock->data.block.block_start_count
1067 <= f->block_start_count))
1069 tree lists = f->cleanup_list_list;
1072 for (; lists; lists = TREE_CHAIN (lists))
1073 /* If the following elt. corresponds to our containing block
1074 then the elt. must be for this block. */
1075 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1078 (*lang_hooks.decls.pushlevel) (0);
1079 (*lang_hooks.decls.set_block) (f->context);
1080 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1081 do_pending_stack_adjust ();
1082 cleanup_insns = get_insns ();
1083 (*lang_hooks.decls.poplevel) (1, 0, 0);
1085 if (cleanup_insns != 0)
1087 = emit_insn_after (cleanup_insns, f->before_jump);
1089 f->cleanup_list_list = TREE_CHAIN (lists);
1093 f->stack_level = stack_level;
1097 /* Return the number of times character C occurs in string S. */
1099 n_occurrences (c, s)
1109 /* Generate RTL for an asm statement (explicit assembler code).
1110 BODY is a STRING_CST node containing the assembler code text,
1111 or an ADDR_EXPR containing a STRING_CST. */
1117 if (TREE_CODE (body) == ADDR_EXPR)
1118 body = TREE_OPERAND (body, 0);
1120 emit_insn (gen_rtx_ASM_INPUT (VOIDmode,
1121 TREE_STRING_POINTER (body)));
1125 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1126 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1127 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1128 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1129 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1130 constraint allows the use of a register operand. And, *IS_INOUT
1131 will be true if the operand is read-write, i.e., if it is used as
1132 an input as well as an output. If *CONSTRAINT_P is not in
1133 canonical form, it will be made canonical. (Note that `+' will be
1134 rpelaced with `=' as part of this process.)
1136 Returns TRUE if all went well; FALSE if an error occurred. */
1139 parse_output_constraint (constraint_p, operand_num, ninputs, noutputs,
1140 allows_mem, allows_reg, is_inout)
1141 const char **constraint_p;
1149 const char *constraint = *constraint_p;
1152 /* Assume the constraint doesn't allow the use of either a register
1154 *allows_mem = false;
1155 *allows_reg = false;
1157 /* Allow the `=' or `+' to not be at the beginning of the string,
1158 since it wasn't explicitly documented that way, and there is a
1159 large body of code that puts it last. Swap the character to
1160 the front, so as not to uglify any place else. */
1161 p = strchr (constraint, '=');
1163 p = strchr (constraint, '+');
1165 /* If the string doesn't contain an `=', issue an error
1169 error ("output operand constraint lacks `='");
1173 /* If the constraint begins with `+', then the operand is both read
1174 from and written to. */
1175 *is_inout = (*p == '+');
1177 /* Canonicalize the output constraint so that it begins with `='. */
1178 if (p != constraint || is_inout)
1181 size_t c_len = strlen (constraint);
1183 if (p != constraint)
1184 warning ("output constraint `%c' for operand %d is not at the beginning",
1187 /* Make a copy of the constraint. */
1188 buf = alloca (c_len + 1);
1189 strcpy (buf, constraint);
1190 /* Swap the first character and the `=' or `+'. */
1191 buf[p - constraint] = buf[0];
1192 /* Make sure the first character is an `='. (Until we do this,
1193 it might be a `+'.) */
1195 /* Replace the constraint with the canonicalized string. */
1196 *constraint_p = ggc_alloc_string (buf, c_len);
1197 constraint = *constraint_p;
1200 /* Loop through the constraint string. */
1201 for (p = constraint + 1; *p; ++p)
1206 error ("operand constraint contains incorrectly positioned '+' or '='");
1210 if (operand_num + 1 == ninputs + noutputs)
1212 error ("`%%' constraint used with last operand");
1217 case 'V': case 'm': case 'o':
1221 case '?': case '!': case '*': case '&': case '#':
1222 case 'E': case 'F': case 'G': case 'H':
1223 case 's': case 'i': case 'n':
1224 case 'I': case 'J': case 'K': case 'L': case 'M':
1225 case 'N': case 'O': case 'P': case ',':
1228 case '0': case '1': case '2': case '3': case '4':
1229 case '5': case '6': case '7': case '8': case '9':
1231 error ("matching constraint not valid in output operand");
1235 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1236 excepting those that expand_call created. So match memory
1253 if (REG_CLASS_FROM_LETTER (*p) != NO_REGS)
1255 #ifdef EXTRA_CONSTRAINT
1256 else if (EXTRA_ADDRESS_CONSTRAINT (*p))
1258 else if (EXTRA_MEMORY_CONSTRAINT (*p))
1262 /* Otherwise we can't assume anything about the nature of
1263 the constraint except that it isn't purely registers.
1264 Treat it like "g" and hope for the best. */
1275 /* Similar, but for input constraints. */
1278 parse_input_constraint (constraint_p, input_num, ninputs, noutputs, ninout,
1279 constraints, allows_mem, allows_reg)
1280 const char **constraint_p;
1285 const char * const * constraints;
1289 const char *constraint = *constraint_p;
1290 const char *orig_constraint = constraint;
1291 size_t c_len = strlen (constraint);
1294 /* Assume the constraint doesn't allow the use of either
1295 a register or memory. */
1296 *allows_mem = false;
1297 *allows_reg = false;
1299 /* Make sure constraint has neither `=', `+', nor '&'. */
1301 for (j = 0; j < c_len; j++)
1302 switch (constraint[j])
1304 case '+': case '=': case '&':
1305 if (constraint == orig_constraint)
1307 error ("input operand constraint contains `%c'", constraint[j]);
1313 if (constraint == orig_constraint
1314 && input_num + 1 == ninputs - ninout)
1316 error ("`%%' constraint used with last operand");
1321 case 'V': case 'm': case 'o':
1326 case '?': case '!': case '*': case '#':
1327 case 'E': case 'F': case 'G': case 'H':
1328 case 's': case 'i': case 'n':
1329 case 'I': case 'J': case 'K': case 'L': case 'M':
1330 case 'N': case 'O': case 'P': case ',':
1333 /* Whether or not a numeric constraint allows a register is
1334 decided by the matching constraint, and so there is no need
1335 to do anything special with them. We must handle them in
1336 the default case, so that we don't unnecessarily force
1337 operands to memory. */
1338 case '0': case '1': case '2': case '3': case '4':
1339 case '5': case '6': case '7': case '8': case '9':
1342 unsigned long match;
1344 match = strtoul (constraint + j, &end, 10);
1345 if (match >= (unsigned long) noutputs)
1347 error ("matching constraint references invalid operand number");
1351 /* Try and find the real constraint for this dup. Only do this
1352 if the matching constraint is the only alternative. */
1354 && (j == 0 || (j == 1 && constraint[0] == '%')))
1356 constraint = constraints[match];
1357 *constraint_p = constraint;
1358 c_len = strlen (constraint);
1363 j = end - constraint;
1377 if (! ISALPHA (constraint[j]))
1379 error ("invalid punctuation `%c' in constraint", constraint[j]);
1382 if (REG_CLASS_FROM_LETTER (constraint[j]) != NO_REGS)
1384 #ifdef EXTRA_CONSTRAINT
1385 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j]))
1387 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j]))
1391 /* Otherwise we can't assume anything about the nature of
1392 the constraint except that it isn't purely registers.
1393 Treat it like "g" and hope for the best. */
1404 /* Check for overlap between registers marked in CLOBBERED_REGS and
1405 anything inappropriate in DECL. Emit error and return TRUE for error,
1409 decl_conflicts_with_clobbers_p (decl, clobbered_regs)
1411 const HARD_REG_SET clobbered_regs;
1413 /* Conflicts between asm-declared register variables and the clobber
1414 list are not allowed. */
1415 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1416 && DECL_REGISTER (decl)
1417 && REG_P (DECL_RTL (decl))
1418 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1420 rtx reg = DECL_RTL (decl);
1423 for (regno = REGNO (reg);
1424 regno < (REGNO (reg)
1425 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1427 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1429 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1430 IDENTIFIER_POINTER (DECL_NAME (decl)));
1432 /* Reset registerness to stop multiple errors emitted for a
1434 DECL_REGISTER (decl) = 0;
1441 /* Generate RTL for an asm statement with arguments.
1442 STRING is the instruction template.
1443 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1444 Each output or input has an expression in the TREE_VALUE and
1445 and a tree list in TREE_PURPOSE which in turn contains a constraint
1446 name in TREE_VALUE (or NULL_TREE) and a constraint string
1448 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1449 that is clobbered by this insn.
1451 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1452 Some elements of OUTPUTS may be replaced with trees representing temporary
1453 values. The caller should copy those temporary values to the originally
1456 VOL nonzero means the insn is volatile; don't optimize it. */
1459 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1460 tree string, outputs, inputs, clobbers;
1462 const char *filename;
1465 rtvec argvec, constraintvec;
1467 int ninputs = list_length (inputs);
1468 int noutputs = list_length (outputs);
1471 HARD_REG_SET clobbered_regs;
1472 int clobber_conflict_found = 0;
1475 /* Vector of RTX's of evaluated output operands. */
1476 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1477 int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
1478 rtx *real_output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1479 enum machine_mode *inout_mode
1480 = (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
1481 const char **constraints
1482 = (const char **) alloca ((noutputs + ninputs) * sizeof (const char *));
1483 /* The insn we have emitted. */
1485 int old_generating_concat_p = generating_concat_p;
1487 /* An ASM with no outputs needs to be treated as volatile, for now. */
1491 if (! check_operand_nalternatives (outputs, inputs))
1494 if (! check_unique_operand_names (outputs, inputs))
1497 string = resolve_operand_names (string, outputs, inputs, constraints);
1499 #ifdef MD_ASM_CLOBBERS
1500 /* Sometimes we wish to automatically clobber registers across an asm.
1501 Case in point is when the i386 backend moved from cc0 to a hard reg --
1502 maintaining source-level compatibility means automatically clobbering
1503 the flags register. */
1504 MD_ASM_CLOBBERS (clobbers);
1507 /* Count the number of meaningful clobbered registers, ignoring what
1508 we would ignore later. */
1510 CLEAR_HARD_REG_SET (clobbered_regs);
1511 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1513 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1515 i = decode_reg_name (regname);
1516 if (i >= 0 || i == -4)
1519 error ("unknown register name `%s' in `asm'", regname);
1521 /* Mark clobbered registers. */
1523 SET_HARD_REG_BIT (clobbered_regs, i);
1528 /* First pass over inputs and outputs checks validity and sets
1529 mark_addressable if needed. */
1532 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1534 tree val = TREE_VALUE (tail);
1535 tree type = TREE_TYPE (val);
1536 const char *constraint;
1541 /* If there's an erroneous arg, emit no insn. */
1542 if (type == error_mark_node)
1545 /* Try to parse the output constraint. If that fails, there's
1546 no point in going further. */
1547 constraint = constraints[i];
1548 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1549 &allows_mem, &allows_reg, &is_inout))
1556 && GET_CODE (DECL_RTL (val)) == REG
1557 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1558 (*lang_hooks.mark_addressable) (val);
1565 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1567 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1571 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1573 bool allows_reg, allows_mem;
1574 const char *constraint;
1576 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1577 would get VOIDmode and that could cause a crash in reload. */
1578 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1581 constraint = constraints[i + noutputs];
1582 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1583 constraints, &allows_mem, &allows_reg))
1586 if (! allows_reg && allows_mem)
1587 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1590 /* Second pass evaluates arguments. */
1593 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1595 tree val = TREE_VALUE (tail);
1596 tree type = TREE_TYPE (val);
1601 if (!parse_output_constraint (&constraints[i], i, ninputs,
1602 noutputs, &allows_mem, &allows_reg,
1606 /* If an output operand is not a decl or indirect ref and our constraint
1607 allows a register, make a temporary to act as an intermediate.
1608 Make the asm insn write into that, then our caller will copy it to
1609 the real output operand. Likewise for promoted variables. */
1611 generating_concat_p = 0;
1613 real_output_rtx[i] = NULL_RTX;
1614 if ((TREE_CODE (val) == INDIRECT_REF
1617 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1618 && ! (GET_CODE (DECL_RTL (val)) == REG
1619 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1623 output_rtx[i] = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1625 if (! allows_reg && GET_CODE (output_rtx[i]) != MEM)
1626 error ("output number %d not directly addressable", i);
1627 if ((! allows_mem && GET_CODE (output_rtx[i]) == MEM)
1628 || GET_CODE (output_rtx[i]) == CONCAT)
1630 real_output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1631 output_rtx[i] = gen_reg_rtx (GET_MODE (output_rtx[i]));
1633 emit_move_insn (output_rtx[i], real_output_rtx[i]);
1638 output_rtx[i] = assign_temp (type, 0, 0, 1);
1639 TREE_VALUE (tail) = make_tree (type, output_rtx[i]);
1642 generating_concat_p = old_generating_concat_p;
1646 inout_mode[ninout] = TYPE_MODE (type);
1647 inout_opnum[ninout++] = i;
1650 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1651 clobber_conflict_found = 1;
1654 /* Make vectors for the expression-rtx, constraint strings,
1655 and named operands. */
1657 argvec = rtvec_alloc (ninputs);
1658 constraintvec = rtvec_alloc (ninputs);
1660 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1661 : GET_MODE (output_rtx[0])),
1662 TREE_STRING_POINTER (string),
1663 empty_string, 0, argvec, constraintvec,
1666 MEM_VOLATILE_P (body) = vol;
1668 /* Eval the inputs and put them into ARGVEC.
1669 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1671 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1673 bool allows_reg, allows_mem;
1674 const char *constraint;
1678 constraint = constraints[i + noutputs];
1679 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1680 constraints, &allows_mem, &allows_reg))
1683 generating_concat_p = 0;
1685 val = TREE_VALUE (tail);
1686 type = TREE_TYPE (val);
1687 op = expand_expr (val, NULL_RTX, VOIDmode, 0);
1689 /* Never pass a CONCAT to an ASM. */
1690 if (GET_CODE (op) == CONCAT)
1691 op = force_reg (GET_MODE (op), op);
1693 if (asm_operand_ok (op, constraint) <= 0)
1696 op = force_reg (TYPE_MODE (type), op);
1697 else if (!allows_mem)
1698 warning ("asm operand %d probably doesn't match constraints",
1700 else if (CONSTANT_P (op))
1701 op = force_const_mem (TYPE_MODE (type), op);
1702 else if (GET_CODE (op) == REG
1703 || GET_CODE (op) == SUBREG
1704 || GET_CODE (op) == ADDRESSOF
1705 || GET_CODE (op) == CONCAT)
1707 tree qual_type = build_qualified_type (type,
1709 | TYPE_QUAL_CONST));
1710 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1712 emit_move_insn (memloc, op);
1716 else if (GET_CODE (op) == MEM && MEM_VOLATILE_P (op))
1718 /* We won't recognize volatile memory as available a
1719 memory_operand at this point. Ignore it. */
1721 else if (queued_subexp_p (op))
1724 /* ??? Leave this only until we have experience with what
1725 happens in combine and elsewhere when constraints are
1727 warning ("asm operand %d probably doesn't match constraints",
1731 generating_concat_p = old_generating_concat_p;
1732 ASM_OPERANDS_INPUT (body, i) = op;
1734 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1735 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1737 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1738 clobber_conflict_found = 1;
1741 /* Protect all the operands from the queue now that they have all been
1744 generating_concat_p = 0;
1746 for (i = 0; i < ninputs - ninout; i++)
1747 ASM_OPERANDS_INPUT (body, i)
1748 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1750 for (i = 0; i < noutputs; i++)
1751 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1753 /* For in-out operands, copy output rtx to input rtx. */
1754 for (i = 0; i < ninout; i++)
1756 int j = inout_opnum[i];
1759 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1762 sprintf (buffer, "%d", j);
1763 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1764 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_alloc_string (buffer, -1));
1767 generating_concat_p = old_generating_concat_p;
1769 /* Now, for each output, construct an rtx
1770 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1771 ARGVEC CONSTRAINTS OPNAMES))
1772 If there is more than one, put them inside a PARALLEL. */
1774 if (noutputs == 1 && nclobbers == 0)
1776 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1777 insn = emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1780 else if (noutputs == 0 && nclobbers == 0)
1782 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1783 insn = emit_insn (body);
1794 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1796 /* For each output operand, store a SET. */
1797 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1799 XVECEXP (body, 0, i)
1800 = gen_rtx_SET (VOIDmode,
1802 gen_rtx_ASM_OPERANDS
1803 (GET_MODE (output_rtx[i]),
1804 TREE_STRING_POINTER (string),
1805 constraints[i], i, argvec, constraintvec,
1808 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1811 /* If there are no outputs (but there are some clobbers)
1812 store the bare ASM_OPERANDS into the PARALLEL. */
1815 XVECEXP (body, 0, i++) = obody;
1817 /* Store (clobber REG) for each clobbered register specified. */
1819 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1821 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1822 int j = decode_reg_name (regname);
1827 if (j == -3) /* `cc', which is not a register */
1830 if (j == -4) /* `memory', don't cache memory across asm */
1832 XVECEXP (body, 0, i++)
1833 = gen_rtx_CLOBBER (VOIDmode,
1836 gen_rtx_SCRATCH (VOIDmode)));
1840 /* Ignore unknown register, error already signaled. */
1844 /* Use QImode since that's guaranteed to clobber just one reg. */
1845 clobbered_reg = gen_rtx_REG (QImode, j);
1847 /* Do sanity check for overlap between clobbers and respectively
1848 input and outputs that hasn't been handled. Such overlap
1849 should have been detected and reported above. */
1850 if (!clobber_conflict_found)
1854 /* We test the old body (obody) contents to avoid tripping
1855 over the under-construction body. */
1856 for (opno = 0; opno < noutputs; opno++)
1857 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1858 internal_error ("asm clobber conflict with output operand");
1860 for (opno = 0; opno < ninputs - ninout; opno++)
1861 if (reg_overlap_mentioned_p (clobbered_reg,
1862 ASM_OPERANDS_INPUT (obody, opno)))
1863 internal_error ("asm clobber conflict with input operand");
1866 XVECEXP (body, 0, i++)
1867 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1870 insn = emit_insn (body);
1873 /* For any outputs that needed reloading into registers, spill them
1874 back to where they belong. */
1875 for (i = 0; i < noutputs; ++i)
1876 if (real_output_rtx[i])
1877 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1882 /* A subroutine of expand_asm_operands. Check that all operands have
1883 the same number of alternatives. Return true if so. */
1886 check_operand_nalternatives (outputs, inputs)
1887 tree outputs, inputs;
1889 if (outputs || inputs)
1891 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1893 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1896 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1898 error ("too many alternatives in `asm'");
1905 const char *constraint
1906 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1908 if (n_occurrences (',', constraint) != nalternatives)
1910 error ("operand constraints for `asm' differ in number of alternatives");
1914 if (TREE_CHAIN (tmp))
1915 tmp = TREE_CHAIN (tmp);
1917 tmp = next, next = 0;
1924 /* A subroutine of expand_asm_operands. Check that all operand names
1925 are unique. Return true if so. We rely on the fact that these names
1926 are identifiers, and so have been canonicalized by get_identifier,
1927 so all we need are pointer comparisons. */
1930 check_unique_operand_names (outputs, inputs)
1931 tree outputs, inputs;
1935 for (i = outputs; i ; i = TREE_CHAIN (i))
1937 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1941 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1942 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1946 for (i = inputs; i ; i = TREE_CHAIN (i))
1948 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1952 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1953 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1955 for (j = outputs; j ; j = TREE_CHAIN (j))
1956 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1963 error ("duplicate asm operand name '%s'",
1964 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1968 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1969 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1970 STRING and in the constraints to those numbers. */
1973 resolve_operand_names (string, outputs, inputs, pconstraints)
1975 tree outputs, inputs;
1976 const char **pconstraints;
1978 char *buffer = xstrdup (TREE_STRING_POINTER (string));
1982 /* Assume that we will not need extra space to perform the substitution.
1983 This because we get to remove '[' and ']', which means we cannot have
1984 a problem until we have more than 999 operands. */
1987 while ((p = strchr (p, '%')) != NULL)
1991 else if (ISALPHA (p[1]) && p[2] == '[')
1999 p = resolve_operand_name_1 (p, outputs, inputs);
2002 string = build_string (strlen (buffer), buffer);
2005 /* Collect output constraints here because it's convenient.
2006 There should be no named operands here; this is verified
2007 in expand_asm_operand. */
2008 for (t = outputs; t ; t = TREE_CHAIN (t), pconstraints++)
2009 *pconstraints = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
2011 /* Substitute [<name>] in input constraint strings. */
2012 for (t = inputs; t ; t = TREE_CHAIN (t), pconstraints++)
2014 const char *c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
2015 if (strchr (c, '[') == NULL)
2019 p = buffer = xstrdup (c);
2020 while ((p = strchr (p, '[')) != NULL)
2021 p = resolve_operand_name_1 (p, outputs, inputs);
2023 *pconstraints = ggc_alloc_string (buffer, -1);
2031 /* A subroutine of resolve_operand_names. P points to the '[' for a
2032 potential named operand of the form [<name>]. In place, replace
2033 the name and brackets with a number. Return a pointer to the
2034 balance of the string after substitution. */
2037 resolve_operand_name_1 (p, outputs, inputs)
2039 tree outputs, inputs;
2046 /* Collect the operand name. */
2047 q = strchr (p, ']');
2050 error ("missing close brace for named operand");
2051 return strchr (p, '\0');
2055 /* Resolve the name to a number. */
2056 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2058 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2061 const char *c = TREE_STRING_POINTER (name);
2062 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2066 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2068 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2071 const char *c = TREE_STRING_POINTER (name);
2072 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2078 error ("undefined named operand '%s'", p + 1);
2082 /* Replace the name with the number. Unfortunately, not all libraries
2083 get the return value of sprintf correct, so search for the end of the
2084 generated string by hand. */
2085 sprintf (p, "%d", op);
2086 p = strchr (p, '\0');
2088 /* Verify the no extra buffer space assumption. */
2092 /* Shift the rest of the buffer down to fill the gap. */
2093 memmove (p, q + 1, strlen (q + 1) + 1);
2098 /* Generate RTL to evaluate the expression EXP
2099 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2100 Provided just for backward-compatibility. expand_expr_stmt_value()
2101 should be used for new code. */
2104 expand_expr_stmt (exp)
2107 expand_expr_stmt_value (exp, -1, 1);
2110 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2111 whether to (1) save the value of the expression, (0) discard it or
2112 (-1) use expr_stmts_for_value to tell. The use of -1 is
2113 deprecated, and retained only for backward compatibility. */
2116 expand_expr_stmt_value (exp, want_value, maybe_last)
2118 int want_value, maybe_last;
2123 if (want_value == -1)
2124 want_value = expr_stmts_for_value != 0;
2126 /* If -W, warn about statements with no side effects,
2127 except for an explicit cast to void (e.g. for assert()), and
2128 except for last statement in ({...}) where they may be useful. */
2130 && (expr_stmts_for_value == 0 || ! maybe_last)
2131 && exp != error_mark_node)
2133 if (! TREE_SIDE_EFFECTS (exp))
2135 if ((extra_warnings || warn_unused_value)
2136 && !(TREE_CODE (exp) == CONVERT_EXPR
2137 && VOID_TYPE_P (TREE_TYPE (exp))))
2138 warning_with_file_and_line (emit_filename, emit_lineno,
2139 "statement with no effect");
2141 else if (warn_unused_value)
2142 warn_if_unused_value (exp);
2145 /* If EXP is of function type and we are expanding statements for
2146 value, convert it to pointer-to-function. */
2147 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2148 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2150 /* The call to `expand_expr' could cause last_expr_type and
2151 last_expr_value to get reset. Therefore, we set last_expr_value
2152 and last_expr_type *after* calling expand_expr. */
2153 value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
2155 type = TREE_TYPE (exp);
2157 /* If all we do is reference a volatile value in memory,
2158 copy it to a register to be sure it is actually touched. */
2159 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2161 if (TYPE_MODE (type) == VOIDmode)
2163 else if (TYPE_MODE (type) != BLKmode)
2164 value = copy_to_reg (value);
2167 rtx lab = gen_label_rtx ();
2169 /* Compare the value with itself to reference it. */
2170 emit_cmp_and_jump_insns (value, value, EQ,
2171 expand_expr (TYPE_SIZE (type),
2172 NULL_RTX, VOIDmode, 0),
2178 /* If this expression is part of a ({...}) and is in memory, we may have
2179 to preserve temporaries. */
2180 preserve_temp_slots (value);
2182 /* Free any temporaries used to evaluate this expression. Any temporary
2183 used as a result of this expression will already have been preserved
2189 last_expr_value = value;
2190 last_expr_type = type;
2196 /* Warn if EXP contains any computations whose results are not used.
2197 Return 1 if a warning is printed; 0 otherwise. */
2200 warn_if_unused_value (exp)
2203 if (TREE_USED (exp))
2206 /* Don't warn about void constructs. This includes casting to void,
2207 void function calls, and statement expressions with a final cast
2209 if (VOID_TYPE_P (TREE_TYPE (exp)))
2212 switch (TREE_CODE (exp))
2214 case PREINCREMENT_EXPR:
2215 case POSTINCREMENT_EXPR:
2216 case PREDECREMENT_EXPR:
2217 case POSTDECREMENT_EXPR:
2222 case METHOD_CALL_EXPR:
2224 case TRY_CATCH_EXPR:
2225 case WITH_CLEANUP_EXPR:
2230 /* For a binding, warn if no side effect within it. */
2231 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2234 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2236 case TRUTH_ORIF_EXPR:
2237 case TRUTH_ANDIF_EXPR:
2238 /* In && or ||, warn if 2nd operand has no side effect. */
2239 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2242 if (TREE_NO_UNUSED_WARNING (exp))
2244 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2246 /* Let people do `(foo (), 0)' without a warning. */
2247 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2249 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2253 case NON_LVALUE_EXPR:
2254 /* Don't warn about conversions not explicit in the user's program. */
2255 if (TREE_NO_UNUSED_WARNING (exp))
2257 /* Assignment to a cast usually results in a cast of a modify.
2258 Don't complain about that. There can be an arbitrary number of
2259 casts before the modify, so we must loop until we find the first
2260 non-cast expression and then test to see if that is a modify. */
2262 tree tem = TREE_OPERAND (exp, 0);
2264 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2265 tem = TREE_OPERAND (tem, 0);
2267 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2268 || TREE_CODE (tem) == CALL_EXPR)
2274 /* Don't warn about automatic dereferencing of references, since
2275 the user cannot control it. */
2276 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2277 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2281 /* Referencing a volatile value is a side effect, so don't warn. */
2283 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2284 && TREE_THIS_VOLATILE (exp))
2287 /* If this is an expression which has no operands, there is no value
2288 to be unused. There are no such language-independent codes,
2289 but front ends may define such. */
2290 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2291 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2295 /* If this is an expression with side effects, don't warn. */
2296 if (TREE_SIDE_EFFECTS (exp))
2299 warning_with_file_and_line (emit_filename, emit_lineno,
2300 "value computed is not used");
2305 /* Clear out the memory of the last expression evaluated. */
2310 last_expr_type = NULL_TREE;
2311 last_expr_value = NULL_RTX;
2314 /* Begin a statement-expression, i.e., a series of statements which
2315 may return a value. Return the RTL_EXPR for this statement expr.
2316 The caller must save that value and pass it to
2317 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2318 in the statement-expression are deallocated at the end of the
2322 expand_start_stmt_expr (has_scope)
2327 /* Make the RTL_EXPR node temporary, not momentary,
2328 so that rtl_expr_chain doesn't become garbage. */
2329 t = make_node (RTL_EXPR);
2330 do_pending_stack_adjust ();
2332 start_sequence_for_rtl_expr (t);
2336 expr_stmts_for_value++;
2340 /* Restore the previous state at the end of a statement that returns a value.
2341 Returns a tree node representing the statement's value and the
2342 insns to compute the value.
2344 The nodes of that expression have been freed by now, so we cannot use them.
2345 But we don't want to do that anyway; the expression has already been
2346 evaluated and now we just want to use the value. So generate a RTL_EXPR
2347 with the proper type and RTL value.
2349 If the last substatement was not an expression,
2350 return something with type `void'. */
2353 expand_end_stmt_expr (t)
2358 if (! last_expr_value || ! last_expr_type)
2360 last_expr_value = const0_rtx;
2361 last_expr_type = void_type_node;
2363 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2364 /* Remove any possible QUEUED. */
2365 last_expr_value = protect_from_queue (last_expr_value, 0);
2369 TREE_TYPE (t) = last_expr_type;
2370 RTL_EXPR_RTL (t) = last_expr_value;
2371 RTL_EXPR_SEQUENCE (t) = get_insns ();
2373 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2377 /* Don't consider deleting this expr or containing exprs at tree level. */
2378 TREE_SIDE_EFFECTS (t) = 1;
2379 /* Propagate volatility of the actual RTL expr. */
2380 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2383 expr_stmts_for_value--;
2388 /* Generate RTL for the start of an if-then. COND is the expression
2389 whose truth should be tested.
2391 If EXITFLAG is nonzero, this conditional is visible to
2392 `exit_something'. */
2395 expand_start_cond (cond, exitflag)
2399 struct nesting *thiscond = ALLOC_NESTING ();
2401 /* Make an entry on cond_stack for the cond we are entering. */
2403 thiscond->desc = COND_NESTING;
2404 thiscond->next = cond_stack;
2405 thiscond->all = nesting_stack;
2406 thiscond->depth = ++nesting_depth;
2407 thiscond->data.cond.next_label = gen_label_rtx ();
2408 /* Before we encounter an `else', we don't need a separate exit label
2409 unless there are supposed to be exit statements
2410 to exit this conditional. */
2411 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2412 thiscond->data.cond.endif_label = thiscond->exit_label;
2413 cond_stack = thiscond;
2414 nesting_stack = thiscond;
2416 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2419 /* Generate RTL between then-clause and the elseif-clause
2420 of an if-then-elseif-.... */
2423 expand_start_elseif (cond)
2426 if (cond_stack->data.cond.endif_label == 0)
2427 cond_stack->data.cond.endif_label = gen_label_rtx ();
2428 emit_jump (cond_stack->data.cond.endif_label);
2429 emit_label (cond_stack->data.cond.next_label);
2430 cond_stack->data.cond.next_label = gen_label_rtx ();
2431 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2434 /* Generate RTL between the then-clause and the else-clause
2435 of an if-then-else. */
2438 expand_start_else ()
2440 if (cond_stack->data.cond.endif_label == 0)
2441 cond_stack->data.cond.endif_label = gen_label_rtx ();
2443 emit_jump (cond_stack->data.cond.endif_label);
2444 emit_label (cond_stack->data.cond.next_label);
2445 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2448 /* After calling expand_start_else, turn this "else" into an "else if"
2449 by providing another condition. */
2452 expand_elseif (cond)
2455 cond_stack->data.cond.next_label = gen_label_rtx ();
2456 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2459 /* Generate RTL for the end of an if-then.
2460 Pop the record for it off of cond_stack. */
2465 struct nesting *thiscond = cond_stack;
2467 do_pending_stack_adjust ();
2468 if (thiscond->data.cond.next_label)
2469 emit_label (thiscond->data.cond.next_label);
2470 if (thiscond->data.cond.endif_label)
2471 emit_label (thiscond->data.cond.endif_label);
2473 POPSTACK (cond_stack);
2477 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2478 loop should be exited by `exit_something'. This is a loop for which
2479 `expand_continue' will jump to the top of the loop.
2481 Make an entry on loop_stack to record the labels associated with
2485 expand_start_loop (exit_flag)
2488 struct nesting *thisloop = ALLOC_NESTING ();
2490 /* Make an entry on loop_stack for the loop we are entering. */
2492 thisloop->desc = LOOP_NESTING;
2493 thisloop->next = loop_stack;
2494 thisloop->all = nesting_stack;
2495 thisloop->depth = ++nesting_depth;
2496 thisloop->data.loop.start_label = gen_label_rtx ();
2497 thisloop->data.loop.end_label = gen_label_rtx ();
2498 thisloop->data.loop.alt_end_label = 0;
2499 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2500 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2501 loop_stack = thisloop;
2502 nesting_stack = thisloop;
2504 do_pending_stack_adjust ();
2506 emit_note (NULL, NOTE_INSN_LOOP_BEG);
2507 emit_label (thisloop->data.loop.start_label);
2512 /* Like expand_start_loop but for a loop where the continuation point
2513 (for expand_continue_loop) will be specified explicitly. */
2516 expand_start_loop_continue_elsewhere (exit_flag)
2519 struct nesting *thisloop = expand_start_loop (exit_flag);
2520 loop_stack->data.loop.continue_label = gen_label_rtx ();
2524 /* Begin a null, aka do { } while (0) "loop". But since the contents
2525 of said loop can still contain a break, we must frob the loop nest. */
2528 expand_start_null_loop ()
2530 struct nesting *thisloop = ALLOC_NESTING ();
2532 /* Make an entry on loop_stack for the loop we are entering. */
2534 thisloop->desc = LOOP_NESTING;
2535 thisloop->next = loop_stack;
2536 thisloop->all = nesting_stack;
2537 thisloop->depth = ++nesting_depth;
2538 thisloop->data.loop.start_label = emit_note (NULL, NOTE_INSN_DELETED);
2539 thisloop->data.loop.end_label = gen_label_rtx ();
2540 thisloop->data.loop.alt_end_label = NULL_RTX;
2541 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2542 thisloop->exit_label = thisloop->data.loop.end_label;
2543 loop_stack = thisloop;
2544 nesting_stack = thisloop;
2549 /* Specify the continuation point for a loop started with
2550 expand_start_loop_continue_elsewhere.
2551 Use this at the point in the code to which a continue statement
2555 expand_loop_continue_here ()
2557 do_pending_stack_adjust ();
2558 emit_note (NULL, NOTE_INSN_LOOP_CONT);
2559 emit_label (loop_stack->data.loop.continue_label);
2562 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2563 Pop the block off of loop_stack. */
2568 rtx start_label = loop_stack->data.loop.start_label;
2570 int eh_regions, debug_blocks;
2572 /* Mark the continue-point at the top of the loop if none elsewhere. */
2573 if (start_label == loop_stack->data.loop.continue_label)
2574 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2576 do_pending_stack_adjust ();
2578 /* If the loop starts with a loop exit, roll that to the end where
2579 it will optimize together with the jump back.
2581 If the loop presently looks like this (in pseudo-C):
2585 if (test) goto end_label;
2591 transform it to look like:
2598 if (test) goto end_label;
2602 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2603 the end of the entry condtional. Without this, our lexical scan
2604 can't tell the difference between an entry conditional and a
2605 body conditional that exits the loop. Mistaking the two means
2606 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2607 screw up loop unrolling.
2609 Things will be oh so much better when loop optimization is done
2610 off of a proper control flow graph... */
2612 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2614 eh_regions = debug_blocks = 0;
2615 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2616 if (GET_CODE (etc_note) == NOTE)
2618 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2621 /* We must not walk into a nested loop. */
2622 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2624 etc_note = NULL_RTX;
2628 /* At the same time, scan for EH region notes, as we don't want
2629 to scrog region nesting. This shouldn't happen, but... */
2630 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2632 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2634 if (--eh_regions < 0)
2635 /* We've come to the end of an EH region, but never saw the
2636 beginning of that region. That means that an EH region
2637 begins before the top of the loop, and ends in the middle
2638 of it. The existence of such a situation violates a basic
2639 assumption in this code, since that would imply that even
2640 when EH_REGIONS is zero, we might move code out of an
2641 exception region. */
2645 /* Likewise for debug scopes. In this case we'll either (1) move
2646 all of the notes if they are properly nested or (2) leave the
2647 notes alone and only rotate the loop at high optimization
2648 levels when we expect to scrog debug info. */
2649 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2651 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2658 && (debug_blocks == 0 || optimize >= 2)
2659 && NEXT_INSN (etc_note) != NULL_RTX
2660 && ! any_condjump_p (get_last_insn ()))
2662 /* We found one. Move everything from START to ETC to the end
2663 of the loop, and add a jump from the top of the loop. */
2664 rtx top_label = gen_label_rtx ();
2665 rtx start_move = start_label;
2667 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2668 then we want to move this note also. */
2669 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2670 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2671 start_move = PREV_INSN (start_move);
2673 emit_label_before (top_label, start_move);
2675 /* Actually move the insns. If the debug scopes are nested, we
2676 can move everything at once. Otherwise we have to move them
2677 one by one and squeeze out the block notes. */
2678 if (debug_blocks == 0)
2679 reorder_insns (start_move, etc_note, get_last_insn ());
2682 rtx insn, next_insn;
2683 for (insn = start_move; insn; insn = next_insn)
2685 /* Figure out which insn comes after this one. We have
2686 to do this before we move INSN. */
2687 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2689 if (GET_CODE (insn) == NOTE
2690 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2691 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2694 reorder_insns (insn, insn, get_last_insn ());
2698 /* Add the jump from the top of the loop. */
2699 emit_jump_insn_before (gen_jump (start_label), top_label);
2700 emit_barrier_before (top_label);
2701 start_label = top_label;
2704 emit_jump (start_label);
2705 emit_note (NULL, NOTE_INSN_LOOP_END);
2706 emit_label (loop_stack->data.loop.end_label);
2708 POPSTACK (loop_stack);
2713 /* Finish a null loop, aka do { } while (0). */
2716 expand_end_null_loop ()
2718 do_pending_stack_adjust ();
2719 emit_label (loop_stack->data.loop.end_label);
2721 POPSTACK (loop_stack);
2726 /* Generate a jump to the current loop's continue-point.
2727 This is usually the top of the loop, but may be specified
2728 explicitly elsewhere. If not currently inside a loop,
2729 return 0 and do nothing; caller will print an error message. */
2732 expand_continue_loop (whichloop)
2733 struct nesting *whichloop;
2735 /* Emit information for branch prediction. */
2738 note = emit_note (NULL, NOTE_INSN_PREDICTION);
2739 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2742 whichloop = loop_stack;
2745 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2750 /* Generate a jump to exit the current loop. If not currently inside a loop,
2751 return 0 and do nothing; caller will print an error message. */
2754 expand_exit_loop (whichloop)
2755 struct nesting *whichloop;
2759 whichloop = loop_stack;
2762 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2766 /* Generate a conditional jump to exit the current loop if COND
2767 evaluates to zero. If not currently inside a loop,
2768 return 0 and do nothing; caller will print an error message. */
2771 expand_exit_loop_if_false (whichloop, cond)
2772 struct nesting *whichloop;
2775 rtx label = gen_label_rtx ();
2780 whichloop = loop_stack;
2783 /* In order to handle fixups, we actually create a conditional jump
2784 around an unconditional branch to exit the loop. If fixups are
2785 necessary, they go before the unconditional branch. */
2787 do_jump (cond, NULL_RTX, label);
2788 last_insn = get_last_insn ();
2789 if (GET_CODE (last_insn) == CODE_LABEL)
2790 whichloop->data.loop.alt_end_label = last_insn;
2791 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2798 /* Like expand_exit_loop_if_false except also emit a note marking
2799 the end of the conditional. Should only be used immediately
2800 after expand_loop_start. */
2803 expand_exit_loop_top_cond (whichloop, cond)
2804 struct nesting *whichloop;
2807 if (! expand_exit_loop_if_false (whichloop, cond))
2810 emit_note (NULL, NOTE_INSN_LOOP_END_TOP_COND);
2814 /* Return nonzero if the loop nest is empty. Else return zero. */
2817 stmt_loop_nest_empty ()
2819 /* cfun->stmt can be NULL if we are building a call to get the
2820 EH context for a setjmp/longjmp EH target and the current
2821 function was a deferred inline function. */
2822 return (cfun->stmt == NULL || loop_stack == NULL);
2825 /* Return nonzero if we should preserve sub-expressions as separate
2826 pseudos. We never do so if we aren't optimizing. We always do so
2827 if -fexpensive-optimizations.
2829 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2830 the loop may still be a small one. */
2833 preserve_subexpressions_p ()
2837 if (flag_expensive_optimizations)
2840 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2843 insn = get_last_insn_anywhere ();
2846 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2847 < n_non_fixed_regs * 3));
2851 /* Generate a jump to exit the current loop, conditional, binding contour
2852 or case statement. Not all such constructs are visible to this function,
2853 only those started with EXIT_FLAG nonzero. Individual languages use
2854 the EXIT_FLAG parameter to control which kinds of constructs you can
2857 If not currently inside anything that can be exited,
2858 return 0 and do nothing; caller will print an error message. */
2861 expand_exit_something ()
2865 for (n = nesting_stack; n; n = n->all)
2866 if (n->exit_label != 0)
2868 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2875 /* Generate RTL to return from the current function, with no value.
2876 (That is, we do not do anything about returning any value.) */
2879 expand_null_return ()
2883 last_insn = get_last_insn ();
2885 /* If this function was declared to return a value, but we
2886 didn't, clobber the return registers so that they are not
2887 propagated live to the rest of the function. */
2888 clobber_return_register ();
2890 expand_null_return_1 (last_insn);
2893 /* Try to guess whether the value of return means error code. */
2894 static enum br_predictor
2895 return_prediction (val)
2898 /* Different heuristics for pointers and scalars. */
2899 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2901 /* NULL is usually not returned. */
2902 if (val == const0_rtx)
2903 return PRED_NULL_RETURN;
2907 /* Negative return values are often used to indicate
2909 if (GET_CODE (val) == CONST_INT
2910 && INTVAL (val) < 0)
2911 return PRED_NEGATIVE_RETURN;
2912 /* Constant return values are also usually erors,
2913 zero/one often mean booleans so exclude them from the
2915 if (CONSTANT_P (val)
2916 && (val != const0_rtx && val != const1_rtx))
2917 return PRED_CONST_RETURN;
2919 return PRED_NO_PREDICTION;
2922 /* Generate RTL to return from the current function, with value VAL. */
2925 expand_value_return (val)
2930 enum br_predictor pred;
2932 if ((pred = return_prediction (val)) != PRED_NO_PREDICTION)
2934 /* Emit information for branch prediction. */
2937 note = emit_note (NULL, NOTE_INSN_PREDICTION);
2939 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2943 last_insn = get_last_insn ();
2944 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2946 /* Copy the value to the return location
2947 unless it's already there. */
2949 if (return_reg != val)
2951 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2952 #ifdef PROMOTE_FUNCTION_RETURN
2953 int unsignedp = TREE_UNSIGNED (type);
2954 enum machine_mode old_mode
2955 = DECL_MODE (DECL_RESULT (current_function_decl));
2956 enum machine_mode mode
2957 = promote_mode (type, old_mode, &unsignedp, 1);
2959 if (mode != old_mode)
2960 val = convert_modes (mode, old_mode, val, unsignedp);
2962 if (GET_CODE (return_reg) == PARALLEL)
2963 emit_group_load (return_reg, val, int_size_in_bytes (type));
2965 emit_move_insn (return_reg, val);
2968 expand_null_return_1 (last_insn);
2971 /* Output a return with no value. If LAST_INSN is nonzero,
2972 pretend that the return takes place after LAST_INSN. */
2975 expand_null_return_1 (last_insn)
2978 rtx end_label = cleanup_label ? cleanup_label : return_label;
2980 clear_pending_stack_adjust ();
2981 do_pending_stack_adjust ();
2985 end_label = return_label = gen_label_rtx ();
2986 expand_goto_internal (NULL_TREE, end_label, last_insn);
2989 /* Generate RTL to evaluate the expression RETVAL and return it
2990 from the current function. */
2993 expand_return (retval)
2996 /* If there are any cleanups to be performed, then they will
2997 be inserted following LAST_INSN. It is desirable
2998 that the last_insn, for such purposes, should be the
2999 last insn before computing the return value. Otherwise, cleanups
3000 which call functions can clobber the return value. */
3001 /* ??? rms: I think that is erroneous, because in C++ it would
3002 run destructors on variables that might be used in the subsequent
3003 computation of the return value. */
3009 /* If function wants no value, give it none. */
3010 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3012 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3014 expand_null_return ();
3018 if (retval == error_mark_node)
3020 /* Treat this like a return of no value from a function that
3022 expand_null_return ();
3025 else if (TREE_CODE (retval) == RESULT_DECL)
3026 retval_rhs = retval;
3027 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3028 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3029 retval_rhs = TREE_OPERAND (retval, 1);
3030 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3031 /* Recognize tail-recursive call to void function. */
3032 retval_rhs = retval;
3034 retval_rhs = NULL_TREE;
3036 last_insn = get_last_insn ();
3038 /* Distribute return down conditional expr if either of the sides
3039 may involve tail recursion (see test below). This enhances the number
3040 of tail recursions we see. Don't do this always since it can produce
3041 sub-optimal code in some cases and we distribute assignments into
3042 conditional expressions when it would help. */
3044 if (optimize && retval_rhs != 0
3045 && frame_offset == 0
3046 && TREE_CODE (retval_rhs) == COND_EXPR
3047 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3048 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3050 rtx label = gen_label_rtx ();
3053 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3054 start_cleanup_deferral ();
3055 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3056 DECL_RESULT (current_function_decl),
3057 TREE_OPERAND (retval_rhs, 1));
3058 TREE_SIDE_EFFECTS (expr) = 1;
3059 expand_return (expr);
3062 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3063 DECL_RESULT (current_function_decl),
3064 TREE_OPERAND (retval_rhs, 2));
3065 TREE_SIDE_EFFECTS (expr) = 1;
3066 expand_return (expr);
3067 end_cleanup_deferral ();
3071 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3073 /* If the result is an aggregate that is being returned in one (or more)
3074 registers, load the registers here. The compiler currently can't handle
3075 copying a BLKmode value into registers. We could put this code in a
3076 more general area (for use by everyone instead of just function
3077 call/return), but until this feature is generally usable it is kept here
3078 (and in expand_call). The value must go into a pseudo in case there
3079 are cleanups that will clobber the real return register. */
3082 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3083 && GET_CODE (result_rtl) == REG)
3086 unsigned HOST_WIDE_INT bitpos, xbitpos;
3087 unsigned HOST_WIDE_INT big_endian_correction = 0;
3088 unsigned HOST_WIDE_INT bytes
3089 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3090 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3091 unsigned int bitsize
3092 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3093 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
3094 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3095 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3096 enum machine_mode tmpmode, result_reg_mode;
3100 expand_null_return ();
3104 /* Structures whose size is not a multiple of a word are aligned
3105 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
3106 machine, this means we must skip the empty high order bytes when
3107 calculating the bit offset. */
3108 if (BYTES_BIG_ENDIAN
3109 && !FUNCTION_ARG_REG_LITTLE_ENDIAN
3110 && bytes % UNITS_PER_WORD)
3111 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3114 /* Copy the structure BITSIZE bits at a time. */
3115 for (bitpos = 0, xbitpos = big_endian_correction;
3116 bitpos < bytes * BITS_PER_UNIT;
3117 bitpos += bitsize, xbitpos += bitsize)
3119 /* We need a new destination pseudo each time xbitpos is
3120 on a word boundary and when xbitpos == big_endian_correction
3121 (the first time through). */
3122 if (xbitpos % BITS_PER_WORD == 0
3123 || xbitpos == big_endian_correction)
3125 /* Generate an appropriate register. */
3126 dst = gen_reg_rtx (word_mode);
3127 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3129 /* Clear the destination before we move anything into it. */
3130 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3133 /* We need a new source operand each time bitpos is on a word
3135 if (bitpos % BITS_PER_WORD == 0)
3136 src = operand_subword_force (result_val,
3137 bitpos / BITS_PER_WORD,
3140 /* Use bitpos for the source extraction (left justified) and
3141 xbitpos for the destination store (right justified). */
3142 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3143 extract_bit_field (src, bitsize,
3144 bitpos % BITS_PER_WORD, 1,
3145 NULL_RTX, word_mode, word_mode,
3150 /* Find the smallest integer mode large enough to hold the
3151 entire structure and use that mode instead of BLKmode
3152 on the USE insn for the return register. */
3153 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3154 tmpmode != VOIDmode;
3155 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3156 /* Have we found a large enough mode? */
3157 if (GET_MODE_SIZE (tmpmode) >= bytes)
3160 /* No suitable mode found. */
3161 if (tmpmode == VOIDmode)
3164 PUT_MODE (result_rtl, tmpmode);
3166 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3167 result_reg_mode = word_mode;
3169 result_reg_mode = tmpmode;
3170 result_reg = gen_reg_rtx (result_reg_mode);
3173 for (i = 0; i < n_regs; i++)
3174 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3177 if (tmpmode != result_reg_mode)
3178 result_reg = gen_lowpart (tmpmode, result_reg);
3180 expand_value_return (result_reg);
3182 else if (retval_rhs != 0
3183 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3184 && (GET_CODE (result_rtl) == REG
3185 || (GET_CODE (result_rtl) == PARALLEL)))
3187 /* Calculate the return value into a temporary (usually a pseudo
3189 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3190 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3192 val = assign_temp (nt, 0, 0, 1);
3193 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3194 val = force_not_mem (val);
3196 /* Return the calculated value, doing cleanups first. */
3197 expand_value_return (val);
3201 /* No cleanups or no hard reg used;
3202 calculate value into hard return reg. */
3203 expand_expr (retval, const0_rtx, VOIDmode, 0);
3205 expand_value_return (result_rtl);
3209 /* Return 1 if the end of the generated RTX is not a barrier.
3210 This means code already compiled can drop through. */
3213 drop_through_at_end_p ()
3215 rtx insn = get_last_insn ();
3216 while (insn && GET_CODE (insn) == NOTE)
3217 insn = PREV_INSN (insn);
3218 return insn && GET_CODE (insn) != BARRIER;
3221 /* Attempt to optimize a potential tail recursion call into a goto.
3222 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3223 where to place the jump to the tail recursion label.
3225 Return TRUE if the call was optimized into a goto. */
3228 optimize_tail_recursion (arguments, last_insn)
3232 /* Finish checking validity, and if valid emit code to set the
3233 argument variables for the new call. */
3234 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3236 if (tail_recursion_label == 0)
3238 tail_recursion_label = gen_label_rtx ();
3239 emit_label_after (tail_recursion_label,
3240 tail_recursion_reentry);
3243 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3250 /* Emit code to alter this function's formal parms for a tail-recursive call.
3251 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3252 FORMALS is the chain of decls of formals.
3253 Return 1 if this can be done;
3254 otherwise return 0 and do not emit any code. */
3257 tail_recursion_args (actuals, formals)
3258 tree actuals, formals;
3260 tree a = actuals, f = formals;
3264 /* Check that number and types of actuals are compatible
3265 with the formals. This is not always true in valid C code.
3266 Also check that no formal needs to be addressable
3267 and that all formals are scalars. */
3269 /* Also count the args. */
3271 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3273 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3274 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3276 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3279 if (a != 0 || f != 0)
3282 /* Compute all the actuals. */
3284 argvec = (rtx *) alloca (i * sizeof (rtx));
3286 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3287 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3289 /* Find which actual values refer to current values of previous formals.
3290 Copy each of them now, before any formal is changed. */
3292 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3296 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3297 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3303 argvec[i] = copy_to_reg (argvec[i]);
3306 /* Store the values of the actuals into the formals. */
3308 for (f = formals, a = actuals, i = 0; f;
3309 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3311 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3312 emit_move_insn (DECL_RTL (f), argvec[i]);
3314 convert_move (DECL_RTL (f), argvec[i],
3315 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3322 /* Generate the RTL code for entering a binding contour.
3323 The variables are declared one by one, by calls to `expand_decl'.
3325 FLAGS is a bitwise or of the following flags:
3327 1 - Nonzero if this construct should be visible to
3330 2 - Nonzero if this contour does not require a
3331 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3332 language-independent code should set this flag because they
3333 will not create corresponding BLOCK nodes. (There should be
3334 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3335 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3336 when expand_end_bindings is called.
3338 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3339 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3343 expand_start_bindings_and_block (flags, block)
3347 struct nesting *thisblock = ALLOC_NESTING ();
3349 int exit_flag = ((flags & 1) != 0);
3350 int block_flag = ((flags & 2) == 0);
3352 /* If a BLOCK is supplied, then the caller should be requesting a
3353 NOTE_INSN_BLOCK_BEG note. */
3354 if (!block_flag && block)
3357 /* Create a note to mark the beginning of the block. */
3360 note = emit_note (NULL, NOTE_INSN_BLOCK_BEG);
3361 NOTE_BLOCK (note) = block;
3364 note = emit_note (NULL, NOTE_INSN_DELETED);
3366 /* Make an entry on block_stack for the block we are entering. */
3368 thisblock->desc = BLOCK_NESTING;
3369 thisblock->next = block_stack;
3370 thisblock->all = nesting_stack;
3371 thisblock->depth = ++nesting_depth;
3372 thisblock->data.block.stack_level = 0;
3373 thisblock->data.block.cleanups = 0;
3374 thisblock->data.block.n_function_calls = 0;
3375 thisblock->data.block.exception_region = 0;
3376 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3378 thisblock->data.block.conditional_code = 0;
3379 thisblock->data.block.last_unconditional_cleanup = note;
3380 /* When we insert instructions after the last unconditional cleanup,
3381 we don't adjust last_insn. That means that a later add_insn will
3382 clobber the instructions we've just added. The easiest way to
3383 fix this is to just insert another instruction here, so that the
3384 instructions inserted after the last unconditional cleanup are
3385 never the last instruction. */
3386 emit_note (NULL, NOTE_INSN_DELETED);
3389 && !(block_stack->data.block.cleanups == NULL_TREE
3390 && block_stack->data.block.outer_cleanups == NULL_TREE))
3391 thisblock->data.block.outer_cleanups
3392 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3393 block_stack->data.block.outer_cleanups);
3395 thisblock->data.block.outer_cleanups = 0;
3396 thisblock->data.block.label_chain = 0;
3397 thisblock->data.block.innermost_stack_block = stack_block_stack;
3398 thisblock->data.block.first_insn = note;
3399 thisblock->data.block.block_start_count = ++current_block_start_count;
3400 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3401 block_stack = thisblock;
3402 nesting_stack = thisblock;
3404 /* Make a new level for allocating stack slots. */
3408 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3409 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3410 expand_expr are made. After we end the region, we know that all
3411 space for all temporaries that were created by TARGET_EXPRs will be
3412 destroyed and their space freed for reuse. */
3415 expand_start_target_temps ()
3417 /* This is so that even if the result is preserved, the space
3418 allocated will be freed, as we know that it is no longer in use. */
3421 /* Start a new binding layer that will keep track of all cleanup
3422 actions to be performed. */
3423 expand_start_bindings (2);
3425 target_temp_slot_level = temp_slot_level;
3429 expand_end_target_temps ()
3431 expand_end_bindings (NULL_TREE, 0, 0);
3433 /* This is so that even if the result is preserved, the space
3434 allocated will be freed, as we know that it is no longer in use. */
3438 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3439 in question represents the outermost pair of curly braces (i.e. the "body
3440 block") of a function or method.
3442 For any BLOCK node representing a "body block" of a function or method, the
3443 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3444 represents the outermost (function) scope for the function or method (i.e.
3445 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3446 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3449 is_body_block (stmt)
3452 if (TREE_CODE (stmt) == BLOCK)
3454 tree parent = BLOCK_SUPERCONTEXT (stmt);
3456 if (parent && TREE_CODE (parent) == BLOCK)
3458 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3460 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3468 /* True if we are currently emitting insns in an area of output code
3469 that is controlled by a conditional expression. This is used by
3470 the cleanup handling code to generate conditional cleanup actions. */
3473 conditional_context ()
3475 return block_stack && block_stack->data.block.conditional_code;
3478 /* Return an opaque pointer to the current nesting level, so frontend code
3479 can check its own sanity. */
3482 current_nesting_level ()
3484 return cfun ? block_stack : 0;
3487 /* Emit a handler label for a nonlocal goto handler.
3488 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3491 expand_nl_handler_label (slot, before_insn)
3492 rtx slot, before_insn;
3495 rtx handler_label = gen_label_rtx ();
3497 /* Don't let cleanup_cfg delete the handler. */
3498 LABEL_PRESERVE_P (handler_label) = 1;
3501 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3502 insns = get_insns ();
3504 emit_insn_before (insns, before_insn);
3506 emit_label (handler_label);
3508 return handler_label;
3511 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3514 expand_nl_goto_receiver ()
3516 #ifdef HAVE_nonlocal_goto
3517 if (! HAVE_nonlocal_goto)
3519 /* First adjust our frame pointer to its actual value. It was
3520 previously set to the start of the virtual area corresponding to
3521 the stacked variables when we branched here and now needs to be
3522 adjusted to the actual hardware fp value.
3524 Assignments are to virtual registers are converted by
3525 instantiate_virtual_regs into the corresponding assignment
3526 to the underlying register (fp in this case) that makes
3527 the original assignment true.
3528 So the following insn will actually be
3529 decrementing fp by STARTING_FRAME_OFFSET. */
3530 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3532 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3533 if (fixed_regs[ARG_POINTER_REGNUM])
3535 #ifdef ELIMINABLE_REGS
3536 /* If the argument pointer can be eliminated in favor of the
3537 frame pointer, we don't need to restore it. We assume here
3538 that if such an elimination is present, it can always be used.
3539 This is the case on all known machines; if we don't make this
3540 assumption, we do unnecessary saving on many machines. */
3541 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3544 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3545 if (elim_regs[i].from == ARG_POINTER_REGNUM
3546 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3549 if (i == ARRAY_SIZE (elim_regs))
3552 /* Now restore our arg pointer from the address at which it
3553 was saved in our stack frame. */
3554 emit_move_insn (virtual_incoming_args_rtx,
3555 copy_to_reg (get_arg_pointer_save_area (cfun)));
3560 #ifdef HAVE_nonlocal_goto_receiver
3561 if (HAVE_nonlocal_goto_receiver)
3562 emit_insn (gen_nonlocal_goto_receiver ());
3566 /* Make handlers for nonlocal gotos taking place in the function calls in
3570 expand_nl_goto_receivers (thisblock)
3571 struct nesting *thisblock;
3574 rtx afterward = gen_label_rtx ();
3579 /* Record the handler address in the stack slot for that purpose,
3580 during this block, saving and restoring the outer value. */
3581 if (thisblock->next != 0)
3582 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3584 rtx save_receiver = gen_reg_rtx (Pmode);
3585 emit_move_insn (XEXP (slot, 0), save_receiver);
3588 emit_move_insn (save_receiver, XEXP (slot, 0));
3589 insns = get_insns ();
3591 emit_insn_before (insns, thisblock->data.block.first_insn);
3594 /* Jump around the handlers; they run only when specially invoked. */
3595 emit_jump (afterward);
3597 /* Make a separate handler for each label. */
3598 link = nonlocal_labels;
3599 slot = nonlocal_goto_handler_slots;
3600 label_list = NULL_RTX;
3601 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3602 /* Skip any labels we shouldn't be able to jump to from here,
3603 we generate one special handler for all of them below which just calls
3605 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3608 lab = expand_nl_handler_label (XEXP (slot, 0),
3609 thisblock->data.block.first_insn);
3610 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3612 expand_nl_goto_receiver ();
3614 /* Jump to the "real" nonlocal label. */
3615 expand_goto (TREE_VALUE (link));
3618 /* A second pass over all nonlocal labels; this time we handle those
3619 we should not be able to jump to at this point. */
3620 link = nonlocal_labels;
3621 slot = nonlocal_goto_handler_slots;
3623 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3624 if (DECL_TOO_LATE (TREE_VALUE (link)))
3627 lab = expand_nl_handler_label (XEXP (slot, 0),
3628 thisblock->data.block.first_insn);
3629 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3635 expand_nl_goto_receiver ();
3636 expand_builtin_trap ();
3639 nonlocal_goto_handler_labels = label_list;
3640 emit_label (afterward);
3643 /* Warn about any unused VARS (which may contain nodes other than
3644 VAR_DECLs, but such nodes are ignored). The nodes are connected
3645 via the TREE_CHAIN field. */
3648 warn_about_unused_variables (vars)
3653 if (warn_unused_variable)
3654 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3655 if (TREE_CODE (decl) == VAR_DECL
3656 && ! TREE_USED (decl)
3657 && ! DECL_IN_SYSTEM_HEADER (decl)
3658 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3659 warning_with_decl (decl, "unused variable `%s'");
3662 /* Generate RTL code to terminate a binding contour.
3664 VARS is the chain of VAR_DECL nodes for the variables bound in this
3665 contour. There may actually be other nodes in this chain, but any
3666 nodes other than VAR_DECLS are ignored.
3668 MARK_ENDS is nonzero if we should put a note at the beginning
3669 and end of this binding contour.
3671 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3672 (That is true automatically if the contour has a saved stack level.) */
3675 expand_end_bindings (vars, mark_ends, dont_jump_in)
3680 struct nesting *thisblock = block_stack;
3682 /* If any of the variables in this scope were not used, warn the
3684 warn_about_unused_variables (vars);
3686 if (thisblock->exit_label)
3688 do_pending_stack_adjust ();
3689 emit_label (thisblock->exit_label);
3692 /* If necessary, make handlers for nonlocal gotos taking
3693 place in the function calls in this block. */
3694 if (function_call_count != thisblock->data.block.n_function_calls
3696 /* Make handler for outermost block
3697 if there were any nonlocal gotos to this function. */
3698 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3699 /* Make handler for inner block if it has something
3700 special to do when you jump out of it. */
3701 : (thisblock->data.block.cleanups != 0
3702 || thisblock->data.block.stack_level != 0)))
3703 expand_nl_goto_receivers (thisblock);
3705 /* Don't allow jumping into a block that has a stack level.
3706 Cleanups are allowed, though. */
3708 || thisblock->data.block.stack_level != 0)
3710 struct label_chain *chain;
3712 /* Any labels in this block are no longer valid to go to.
3713 Mark them to cause an error message. */
3714 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3716 DECL_TOO_LATE (chain->label) = 1;
3717 /* If any goto without a fixup came to this label,
3718 that must be an error, because gotos without fixups
3719 come from outside all saved stack-levels. */
3720 if (TREE_ADDRESSABLE (chain->label))
3721 error_with_decl (chain->label,
3722 "label `%s' used before containing binding contour");
3726 /* Restore stack level in effect before the block
3727 (only if variable-size objects allocated). */
3728 /* Perform any cleanups associated with the block. */
3730 if (thisblock->data.block.stack_level != 0
3731 || thisblock->data.block.cleanups != 0)
3736 /* Don't let cleanups affect ({...}) constructs. */
3737 int old_expr_stmts_for_value = expr_stmts_for_value;
3738 rtx old_last_expr_value = last_expr_value;
3739 tree old_last_expr_type = last_expr_type;
3740 expr_stmts_for_value = 0;
3742 /* Only clean up here if this point can actually be reached. */
3743 insn = get_last_insn ();
3744 if (GET_CODE (insn) == NOTE)
3745 insn = prev_nonnote_insn (insn);
3746 reachable = (! insn || GET_CODE (insn) != BARRIER);
3748 /* Do the cleanups. */
3749 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3751 do_pending_stack_adjust ();
3753 expr_stmts_for_value = old_expr_stmts_for_value;
3754 last_expr_value = old_last_expr_value;
3755 last_expr_type = old_last_expr_type;
3757 /* Restore the stack level. */
3759 if (reachable && thisblock->data.block.stack_level != 0)
3761 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3762 thisblock->data.block.stack_level, NULL_RTX);
3763 if (nonlocal_goto_handler_slots != 0)
3764 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3768 /* Any gotos out of this block must also do these things.
3769 Also report any gotos with fixups that came to labels in this
3771 fixup_gotos (thisblock,
3772 thisblock->data.block.stack_level,
3773 thisblock->data.block.cleanups,
3774 thisblock->data.block.first_insn,
3778 /* Mark the beginning and end of the scope if requested.
3779 We do this now, after running cleanups on the variables
3780 just going out of scope, so they are in scope for their cleanups. */
3784 rtx note = emit_note (NULL, NOTE_INSN_BLOCK_END);
3785 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3788 /* Get rid of the beginning-mark if we don't make an end-mark. */
3789 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3791 /* Restore the temporary level of TARGET_EXPRs. */
3792 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3794 /* Restore block_stack level for containing block. */
3796 stack_block_stack = thisblock->data.block.innermost_stack_block;
3797 POPSTACK (block_stack);
3799 /* Pop the stack slot nesting and free any slots at this level. */
3803 /* Generate code to save the stack pointer at the start of the current block
3804 and set up to restore it on exit. */
3807 save_stack_pointer ()
3809 struct nesting *thisblock = block_stack;
3811 if (thisblock->data.block.stack_level == 0)
3813 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3814 &thisblock->data.block.stack_level,
3815 thisblock->data.block.first_insn);
3816 stack_block_stack = thisblock;
3820 /* Generate RTL for the automatic variable declaration DECL.
3821 (Other kinds of declarations are simply ignored if seen here.) */
3827 struct nesting *thisblock;
3830 type = TREE_TYPE (decl);
3832 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3833 type in case this node is used in a reference. */
3834 if (TREE_CODE (decl) == CONST_DECL)
3836 DECL_MODE (decl) = TYPE_MODE (type);
3837 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3838 DECL_SIZE (decl) = TYPE_SIZE (type);
3839 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3843 /* Otherwise, only automatic variables need any expansion done. Static and
3844 external variables, and external functions, will be handled by
3845 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3846 nothing. PARM_DECLs are handled in `assign_parms'. */
3847 if (TREE_CODE (decl) != VAR_DECL)
3850 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3853 thisblock = block_stack;
3855 /* Create the RTL representation for the variable. */
3857 if (type == error_mark_node)
3858 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3860 else if (DECL_SIZE (decl) == 0)
3861 /* Variable with incomplete type. */
3864 if (DECL_INITIAL (decl) == 0)
3865 /* Error message was already done; now avoid a crash. */
3866 x = gen_rtx_MEM (BLKmode, const0_rtx);
3868 /* An initializer is going to decide the size of this array.
3869 Until we know the size, represent its address with a reg. */
3870 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3872 set_mem_attributes (x, decl, 1);
3873 SET_DECL_RTL (decl, x);
3875 else if (DECL_MODE (decl) != BLKmode
3876 /* If -ffloat-store, don't put explicit float vars
3878 && !(flag_float_store
3879 && TREE_CODE (type) == REAL_TYPE)
3880 && ! TREE_THIS_VOLATILE (decl)
3881 && (DECL_REGISTER (decl) || optimize))
3883 /* Automatic variable that can go in a register. */
3884 int unsignedp = TREE_UNSIGNED (type);
3885 enum machine_mode reg_mode
3886 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3888 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3890 if (GET_CODE (DECL_RTL (decl)) == REG)
3891 REGNO_DECL (REGNO (DECL_RTL (decl))) = decl;
3892 else if (GET_CODE (DECL_RTL (decl)) == CONCAT)
3894 REGNO_DECL (REGNO (XEXP (DECL_RTL (decl), 0))) = decl;
3895 REGNO_DECL (REGNO (XEXP (DECL_RTL (decl), 1))) = decl;
3898 mark_user_reg (DECL_RTL (decl));
3900 if (POINTER_TYPE_P (type))
3901 mark_reg_pointer (DECL_RTL (decl),
3902 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3904 maybe_set_unchanging (DECL_RTL (decl), decl);
3906 /* If something wants our address, try to use ADDRESSOF. */
3907 if (TREE_ADDRESSABLE (decl))
3908 put_var_into_stack (decl);
3911 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3912 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3913 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3914 STACK_CHECK_MAX_VAR_SIZE)))
3916 /* Variable of fixed size that goes on the stack. */
3921 /* If we previously made RTL for this decl, it must be an array
3922 whose size was determined by the initializer.
3923 The old address was a register; set that register now
3924 to the proper address. */
3925 if (DECL_RTL_SET_P (decl))
3927 if (GET_CODE (DECL_RTL (decl)) != MEM
3928 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3930 oldaddr = XEXP (DECL_RTL (decl), 0);
3933 /* Set alignment we actually gave this decl. */
3934 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3935 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3936 DECL_USER_ALIGN (decl) = 0;
3938 x = assign_temp (decl, 1, 1, 1);
3939 set_mem_attributes (x, decl, 1);
3940 SET_DECL_RTL (decl, x);
3944 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3945 if (addr != oldaddr)
3946 emit_move_insn (oldaddr, addr);
3950 /* Dynamic-size object: must push space on the stack. */
3952 rtx address, size, x;
3954 /* Record the stack pointer on entry to block, if have
3955 not already done so. */
3956 do_pending_stack_adjust ();
3957 save_stack_pointer ();
3959 /* In function-at-a-time mode, variable_size doesn't expand this,
3961 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3962 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3963 const0_rtx, VOIDmode, 0);
3965 /* Compute the variable's size, in bytes. */
3966 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
3969 /* Allocate space on the stack for the variable. Note that
3970 DECL_ALIGN says how the variable is to be aligned and we
3971 cannot use it to conclude anything about the alignment of
3973 address = allocate_dynamic_stack_space (size, NULL_RTX,
3974 TYPE_ALIGN (TREE_TYPE (decl)));
3976 /* Reference the variable indirect through that rtx. */
3977 x = gen_rtx_MEM (DECL_MODE (decl), address);
3978 set_mem_attributes (x, decl, 1);
3979 SET_DECL_RTL (decl, x);
3982 /* Indicate the alignment we actually gave this variable. */
3983 #ifdef STACK_BOUNDARY
3984 DECL_ALIGN (decl) = STACK_BOUNDARY;
3986 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3988 DECL_USER_ALIGN (decl) = 0;
3992 /* Emit code to perform the initialization of a declaration DECL. */
3995 expand_decl_init (decl)
3998 int was_used = TREE_USED (decl);
4000 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
4001 for static decls. */
4002 if (TREE_CODE (decl) == CONST_DECL
4003 || TREE_STATIC (decl))
4006 /* Compute and store the initial value now. */
4008 if (DECL_INITIAL (decl) == error_mark_node)
4010 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4012 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4013 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4014 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4018 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4020 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
4021 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
4025 /* Don't let the initialization count as "using" the variable. */
4026 TREE_USED (decl) = was_used;
4028 /* Free any temporaries we made while initializing the decl. */
4029 preserve_temp_slots (NULL_RTX);
4033 /* CLEANUP is an expression to be executed at exit from this binding contour;
4034 for example, in C++, it might call the destructor for this variable.
4036 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4037 CLEANUP multiple times, and have the correct semantics. This
4038 happens in exception handling, for gotos, returns, breaks that
4039 leave the current scope.
4041 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4042 that is not associated with any particular variable. */
4045 expand_decl_cleanup (decl, cleanup)
4048 struct nesting *thisblock;
4050 /* Error if we are not in any block. */
4051 if (cfun == 0 || block_stack == 0)
4054 thisblock = block_stack;
4056 /* Record the cleanup if there is one. */
4062 tree *cleanups = &thisblock->data.block.cleanups;
4063 int cond_context = conditional_context ();
4067 rtx flag = gen_reg_rtx (word_mode);
4072 emit_move_insn (flag, const0_rtx);
4073 set_flag_0 = get_insns ();
4076 thisblock->data.block.last_unconditional_cleanup
4077 = emit_insn_after (set_flag_0,
4078 thisblock->data.block.last_unconditional_cleanup);
4080 emit_move_insn (flag, const1_rtx);
4082 cond = build_decl (VAR_DECL, NULL_TREE,
4083 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4084 SET_DECL_RTL (cond, flag);
4086 /* Conditionalize the cleanup. */
4087 cleanup = build (COND_EXPR, void_type_node,
4088 (*lang_hooks.truthvalue_conversion) (cond),
4089 cleanup, integer_zero_node);
4090 cleanup = fold (cleanup);
4092 cleanups = &thisblock->data.block.cleanups;
4095 cleanup = unsave_expr (cleanup);
4097 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4100 /* If this block has a cleanup, it belongs in stack_block_stack. */
4101 stack_block_stack = thisblock;
4108 if (! using_eh_for_cleanups_p)
4109 TREE_ADDRESSABLE (t) = 1;
4111 expand_eh_region_start ();
4118 thisblock->data.block.last_unconditional_cleanup
4119 = emit_insn_after (seq,
4120 thisblock->data.block.last_unconditional_cleanup);
4124 thisblock->data.block.last_unconditional_cleanup
4126 /* When we insert instructions after the last unconditional cleanup,
4127 we don't adjust last_insn. That means that a later add_insn will
4128 clobber the instructions we've just added. The easiest way to
4129 fix this is to just insert another instruction here, so that the
4130 instructions inserted after the last unconditional cleanup are
4131 never the last instruction. */
4132 emit_note (NULL, NOTE_INSN_DELETED);
4138 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4142 expand_decl_cleanup_eh (decl, cleanup, eh_only)
4146 int ret = expand_decl_cleanup (decl, cleanup);
4149 tree node = block_stack->data.block.cleanups;
4150 CLEANUP_EH_ONLY (node) = eh_only;
4155 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4156 DECL_ELTS is the list of elements that belong to DECL's type.
4157 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4160 expand_anon_union_decl (decl, cleanup, decl_elts)
4161 tree decl, cleanup, decl_elts;
4163 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4167 /* If any of the elements are addressable, so is the entire union. */
4168 for (t = decl_elts; t; t = TREE_CHAIN (t))
4169 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4171 TREE_ADDRESSABLE (decl) = 1;
4176 expand_decl_cleanup (decl, cleanup);
4177 x = DECL_RTL (decl);
4179 /* Go through the elements, assigning RTL to each. */
4180 for (t = decl_elts; t; t = TREE_CHAIN (t))
4182 tree decl_elt = TREE_VALUE (t);
4183 tree cleanup_elt = TREE_PURPOSE (t);
4184 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4186 /* If any of the elements are addressable, so is the entire
4188 if (TREE_USED (decl_elt))
4189 TREE_USED (decl) = 1;
4191 /* Propagate the union's alignment to the elements. */
4192 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4193 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4195 /* If the element has BLKmode and the union doesn't, the union is
4196 aligned such that the element doesn't need to have BLKmode, so
4197 change the element's mode to the appropriate one for its size. */
4198 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4199 DECL_MODE (decl_elt) = mode
4200 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4202 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4203 instead create a new MEM rtx with the proper mode. */
4204 if (GET_CODE (x) == MEM)
4206 if (mode == GET_MODE (x))
4207 SET_DECL_RTL (decl_elt, x);
4209 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4211 else if (GET_CODE (x) == REG)
4213 if (mode == GET_MODE (x))
4214 SET_DECL_RTL (decl_elt, x);
4216 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4221 /* Record the cleanup if there is one. */
4224 thisblock->data.block.cleanups
4225 = tree_cons (decl_elt, cleanup_elt,
4226 thisblock->data.block.cleanups);
4230 /* Expand a list of cleanups LIST.
4231 Elements may be expressions or may be nested lists.
4233 If DONT_DO is nonnull, then any list-element
4234 whose TREE_PURPOSE matches DONT_DO is omitted.
4235 This is sometimes used to avoid a cleanup associated with
4236 a value that is being returned out of the scope.
4238 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4239 goto and handle protection regions specially in that case.
4241 If REACHABLE, we emit code, otherwise just inform the exception handling
4242 code about this finalization. */
4245 expand_cleanups (list, dont_do, in_fixup, reachable)
4252 for (tail = list; tail; tail = TREE_CHAIN (tail))
4253 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
4255 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4256 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
4259 if (! in_fixup && using_eh_for_cleanups_p)
4260 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4262 if (reachable && !CLEANUP_EH_ONLY (tail))
4264 /* Cleanups may be run multiple times. For example,
4265 when exiting a binding contour, we expand the
4266 cleanups associated with that contour. When a goto
4267 within that binding contour has a target outside that
4268 contour, it will expand all cleanups from its scope to
4269 the target. Though the cleanups are expanded multiple
4270 times, the control paths are non-overlapping so the
4271 cleanups will not be executed twice. */
4273 /* We may need to protect from outer cleanups. */
4274 if (in_fixup && using_eh_for_cleanups_p)
4276 expand_eh_region_start ();
4278 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4280 expand_eh_region_end_fixup (TREE_VALUE (tail));
4283 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4291 /* Mark when the context we are emitting RTL for as a conditional
4292 context, so that any cleanup actions we register with
4293 expand_decl_init will be properly conditionalized when those
4294 cleanup actions are later performed. Must be called before any
4295 expression (tree) is expanded that is within a conditional context. */
4298 start_cleanup_deferral ()
4300 /* block_stack can be NULL if we are inside the parameter list. It is
4301 OK to do nothing, because cleanups aren't possible here. */
4303 ++block_stack->data.block.conditional_code;
4306 /* Mark the end of a conditional region of code. Because cleanup
4307 deferrals may be nested, we may still be in a conditional region
4308 after we end the currently deferred cleanups, only after we end all
4309 deferred cleanups, are we back in unconditional code. */
4312 end_cleanup_deferral ()
4314 /* block_stack can be NULL if we are inside the parameter list. It is
4315 OK to do nothing, because cleanups aren't possible here. */
4317 --block_stack->data.block.conditional_code;
4320 /* Move all cleanups from the current block_stack
4321 to the containing block_stack, where they are assumed to
4322 have been created. If anything can cause a temporary to
4323 be created, but not expanded for more than one level of
4324 block_stacks, then this code will have to change. */
4329 struct nesting *block = block_stack;
4330 struct nesting *outer = block->next;
4332 outer->data.block.cleanups
4333 = chainon (block->data.block.cleanups,
4334 outer->data.block.cleanups);
4335 block->data.block.cleanups = 0;
4339 last_cleanup_this_contour ()
4341 if (block_stack == 0)
4344 return block_stack->data.block.cleanups;
4347 /* Return 1 if there are any pending cleanups at this point.
4348 If THIS_CONTOUR is nonzero, check the current contour as well.
4349 Otherwise, look only at the contours that enclose this one. */
4352 any_pending_cleanups (this_contour)
4355 struct nesting *block;
4357 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4360 if (this_contour && block_stack->data.block.cleanups != NULL)
4362 if (block_stack->data.block.cleanups == 0
4363 && block_stack->data.block.outer_cleanups == 0)
4366 for (block = block_stack->next; block; block = block->next)
4367 if (block->data.block.cleanups != 0)
4373 /* Enter a case (Pascal) or switch (C) statement.
4374 Push a block onto case_stack and nesting_stack
4375 to accumulate the case-labels that are seen
4376 and to record the labels generated for the statement.
4378 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4379 Otherwise, this construct is transparent for `exit_something'.
4381 EXPR is the index-expression to be dispatched on.
4382 TYPE is its nominal type. We could simply convert EXPR to this type,
4383 but instead we take short cuts. */
4386 expand_start_case (exit_flag, expr, type, printname)
4390 const char *printname;
4392 struct nesting *thiscase = ALLOC_NESTING ();
4394 /* Make an entry on case_stack for the case we are entering. */
4396 thiscase->desc = CASE_NESTING;
4397 thiscase->next = case_stack;
4398 thiscase->all = nesting_stack;
4399 thiscase->depth = ++nesting_depth;
4400 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4401 thiscase->data.case_stmt.case_list = 0;
4402 thiscase->data.case_stmt.index_expr = expr;
4403 thiscase->data.case_stmt.nominal_type = type;
4404 thiscase->data.case_stmt.default_label = 0;
4405 thiscase->data.case_stmt.printname = printname;
4406 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4407 case_stack = thiscase;
4408 nesting_stack = thiscase;
4410 do_pending_stack_adjust ();
4412 /* Make sure case_stmt.start points to something that won't
4413 need any transformation before expand_end_case. */
4414 if (GET_CODE (get_last_insn ()) != NOTE)
4415 emit_note (NULL, NOTE_INSN_DELETED);
4417 thiscase->data.case_stmt.start = get_last_insn ();
4419 start_cleanup_deferral ();
4422 /* Start a "dummy case statement" within which case labels are invalid
4423 and are not connected to any larger real case statement.
4424 This can be used if you don't want to let a case statement jump
4425 into the middle of certain kinds of constructs. */
4428 expand_start_case_dummy ()
4430 struct nesting *thiscase = ALLOC_NESTING ();
4432 /* Make an entry on case_stack for the dummy. */
4434 thiscase->desc = CASE_NESTING;
4435 thiscase->next = case_stack;
4436 thiscase->all = nesting_stack;
4437 thiscase->depth = ++nesting_depth;
4438 thiscase->exit_label = 0;
4439 thiscase->data.case_stmt.case_list = 0;
4440 thiscase->data.case_stmt.start = 0;
4441 thiscase->data.case_stmt.nominal_type = 0;
4442 thiscase->data.case_stmt.default_label = 0;
4443 case_stack = thiscase;
4444 nesting_stack = thiscase;
4445 start_cleanup_deferral ();
4448 /* End a dummy case statement. */
4451 expand_end_case_dummy ()
4453 end_cleanup_deferral ();
4454 POPSTACK (case_stack);
4457 /* Return the data type of the index-expression
4458 of the innermost case statement, or null if none. */
4461 case_index_expr_type ()
4464 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
4471 /* If this is the first label, warn if any insns have been emitted. */
4472 if (case_stack->data.case_stmt.line_number_status >= 0)
4476 restore_line_number_status
4477 (case_stack->data.case_stmt.line_number_status);
4478 case_stack->data.case_stmt.line_number_status = -1;
4480 for (insn = case_stack->data.case_stmt.start;
4482 insn = NEXT_INSN (insn))
4484 if (GET_CODE (insn) == CODE_LABEL)
4486 if (GET_CODE (insn) != NOTE
4487 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4490 insn = PREV_INSN (insn);
4491 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4493 /* If insn is zero, then there must have been a syntax error. */
4495 warning_with_file_and_line (NOTE_SOURCE_FILE (insn),
4496 NOTE_LINE_NUMBER (insn),
4497 "unreachable code at beginning of %s",
4498 case_stack->data.case_stmt.printname);
4505 /* Accumulate one case or default label inside a case or switch statement.
4506 VALUE is the value of the case (a null pointer, for a default label).
4507 The function CONVERTER, when applied to arguments T and V,
4508 converts the value V to the type T.
4510 If not currently inside a case or switch statement, return 1 and do
4511 nothing. The caller will print a language-specific error message.
4512 If VALUE is a duplicate or overlaps, return 2 and do nothing
4513 except store the (first) duplicate node in *DUPLICATE.
4514 If VALUE is out of range, return 3 and do nothing.
4515 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4516 Return 0 on success.
4518 Extended to handle range statements. */
4521 pushcase (value, converter, label, duplicate)
4523 tree (*converter) PARAMS ((tree, tree));
4530 /* Fail if not inside a real case statement. */
4531 if (! (case_stack && case_stack->data.case_stmt.start))
4534 if (stack_block_stack
4535 && stack_block_stack->depth > case_stack->depth)
4538 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4539 nominal_type = case_stack->data.case_stmt.nominal_type;
4541 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4542 if (index_type == error_mark_node)
4545 /* Convert VALUE to the type in which the comparisons are nominally done. */
4547 value = (*converter) (nominal_type, value);
4551 /* Fail if this value is out of range for the actual type of the index
4552 (which may be narrower than NOMINAL_TYPE). */
4554 && (TREE_CONSTANT_OVERFLOW (value)
4555 || ! int_fits_type_p (value, index_type)))
4558 return add_case_node (value, value, label, duplicate);
4561 /* Like pushcase but this case applies to all values between VALUE1 and
4562 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4563 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4564 starts at VALUE1 and ends at the highest value of the index type.
4565 If both are NULL, this case applies to all values.
4567 The return value is the same as that of pushcase but there is one
4568 additional error code: 4 means the specified range was empty. */
4571 pushcase_range (value1, value2, converter, label, duplicate)
4572 tree value1, value2;
4573 tree (*converter) PARAMS ((tree, tree));
4580 /* Fail if not inside a real case statement. */
4581 if (! (case_stack && case_stack->data.case_stmt.start))
4584 if (stack_block_stack
4585 && stack_block_stack->depth > case_stack->depth)
4588 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4589 nominal_type = case_stack->data.case_stmt.nominal_type;
4591 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4592 if (index_type == error_mark_node)
4597 /* Convert VALUEs to type in which the comparisons are nominally done
4598 and replace any unspecified value with the corresponding bound. */
4600 value1 = TYPE_MIN_VALUE (index_type);
4602 value2 = TYPE_MAX_VALUE (index_type);
4604 /* Fail if the range is empty. Do this before any conversion since
4605 we want to allow out-of-range empty ranges. */
4606 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4609 /* If the max was unbounded, use the max of the nominal_type we are
4610 converting to. Do this after the < check above to suppress false
4613 value2 = TYPE_MAX_VALUE (nominal_type);
4615 value1 = (*converter) (nominal_type, value1);
4616 value2 = (*converter) (nominal_type, value2);
4618 /* Fail if these values are out of range. */
4619 if (TREE_CONSTANT_OVERFLOW (value1)
4620 || ! int_fits_type_p (value1, index_type))
4623 if (TREE_CONSTANT_OVERFLOW (value2)
4624 || ! int_fits_type_p (value2, index_type))
4627 return add_case_node (value1, value2, label, duplicate);
4630 /* Do the actual insertion of a case label for pushcase and pushcase_range
4631 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4632 slowdown for large switch statements. */
4635 add_case_node (low, high, label, duplicate)
4640 struct case_node *p, **q, *r;
4642 /* If there's no HIGH value, then this is not a case range; it's
4643 just a simple case label. But that's just a degenerate case
4648 /* Handle default labels specially. */
4651 if (case_stack->data.case_stmt.default_label != 0)
4653 *duplicate = case_stack->data.case_stmt.default_label;
4656 case_stack->data.case_stmt.default_label = label;
4657 expand_label (label);
4661 q = &case_stack->data.case_stmt.case_list;
4668 /* Keep going past elements distinctly greater than HIGH. */
4669 if (tree_int_cst_lt (high, p->low))
4672 /* or distinctly less than LOW. */
4673 else if (tree_int_cst_lt (p->high, low))
4678 /* We have an overlap; this is an error. */
4679 *duplicate = p->code_label;
4684 /* Add this label to the chain, and succeed. */
4686 r = (struct case_node *) ggc_alloc (sizeof (struct case_node));
4689 /* If the bounds are equal, turn this into the one-value case. */
4690 if (tree_int_cst_equal (low, high))
4695 r->code_label = label;
4696 expand_label (label);
4706 struct case_node *s;
4712 if (! (b = p->balance))
4713 /* Growth propagation from left side. */
4720 if ((p->left = s = r->right))
4729 if ((r->parent = s))
4737 case_stack->data.case_stmt.case_list = r;
4740 /* r->balance == +1 */
4745 struct case_node *t = r->right;
4747 if ((p->left = s = t->right))
4751 if ((r->right = s = t->left))
4765 if ((t->parent = s))
4773 case_stack->data.case_stmt.case_list = t;
4780 /* p->balance == +1; growth of left side balances the node. */
4790 if (! (b = p->balance))
4791 /* Growth propagation from right side. */
4799 if ((p->right = s = r->left))
4807 if ((r->parent = s))
4816 case_stack->data.case_stmt.case_list = r;
4820 /* r->balance == -1 */
4824 struct case_node *t = r->left;
4826 if ((p->right = s = t->left))
4831 if ((r->left = s = t->right))
4845 if ((t->parent = s))
4854 case_stack->data.case_stmt.case_list = t;
4860 /* p->balance == -1; growth of right side balances the node. */
4873 /* Returns the number of possible values of TYPE.
4874 Returns -1 if the number is unknown, variable, or if the number does not
4875 fit in a HOST_WIDE_INT.
4876 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4877 do not increase monotonically (there may be duplicates);
4878 to 1 if the values increase monotonically, but not always by 1;
4879 otherwise sets it to 0. */
4882 all_cases_count (type, sparseness)
4887 HOST_WIDE_INT count, minval, lastval;
4891 switch (TREE_CODE (type))
4898 count = 1 << BITS_PER_UNIT;
4903 if (TYPE_MAX_VALUE (type) != 0
4904 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4905 TYPE_MIN_VALUE (type))))
4906 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4907 convert (type, integer_zero_node))))
4908 && host_integerp (t, 1))
4909 count = tree_low_cst (t, 1);
4915 /* Don't waste time with enumeral types with huge values. */
4916 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4917 || TYPE_MAX_VALUE (type) == 0
4918 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4921 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4924 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4926 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4928 if (*sparseness == 2 || thisval <= lastval)
4930 else if (thisval != minval + count)
4941 #define BITARRAY_TEST(ARRAY, INDEX) \
4942 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4943 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4944 #define BITARRAY_SET(ARRAY, INDEX) \
4945 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4946 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4948 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4949 with the case values we have seen, assuming the case expression
4951 SPARSENESS is as determined by all_cases_count.
4953 The time needed is proportional to COUNT, unless
4954 SPARSENESS is 2, in which case quadratic time is needed. */
4957 mark_seen_cases (type, cases_seen, count, sparseness)
4959 unsigned char *cases_seen;
4960 HOST_WIDE_INT count;
4963 tree next_node_to_try = NULL_TREE;
4964 HOST_WIDE_INT next_node_offset = 0;
4966 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4967 tree val = make_node (INTEGER_CST);
4969 TREE_TYPE (val) = type;
4973 else if (sparseness == 2)
4976 unsigned HOST_WIDE_INT xlo;
4978 /* This less efficient loop is only needed to handle
4979 duplicate case values (multiple enum constants
4980 with the same value). */
4981 TREE_TYPE (val) = TREE_TYPE (root->low);
4982 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4983 t = TREE_CHAIN (t), xlo++)
4985 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4986 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4990 /* Keep going past elements distinctly greater than VAL. */
4991 if (tree_int_cst_lt (val, n->low))
4994 /* or distinctly less than VAL. */
4995 else if (tree_int_cst_lt (n->high, val))
5000 /* We have found a matching range. */
5001 BITARRAY_SET (cases_seen, xlo);
5011 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
5013 for (n = root; n; n = n->right)
5015 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
5016 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
5017 while (! tree_int_cst_lt (n->high, val))
5019 /* Calculate (into xlo) the "offset" of the integer (val).
5020 The element with lowest value has offset 0, the next smallest
5021 element has offset 1, etc. */
5023 unsigned HOST_WIDE_INT xlo;
5027 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
5029 /* The TYPE_VALUES will be in increasing order, so
5030 starting searching where we last ended. */
5031 t = next_node_to_try;
5032 xlo = next_node_offset;
5038 t = TYPE_VALUES (type);
5041 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5043 next_node_to_try = TREE_CHAIN (t);
5044 next_node_offset = xlo + 1;
5049 if (t == next_node_to_try)
5058 t = TYPE_MIN_VALUE (type);
5060 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5064 add_double (xlo, xhi,
5065 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5069 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5070 BITARRAY_SET (cases_seen, xlo);
5072 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5074 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5080 /* Given a switch statement with an expression that is an enumeration
5081 type, warn if any of the enumeration type's literals are not
5082 covered by the case expressions of the switch. Also, warn if there
5083 are any extra switch cases that are *not* elements of the
5088 At one stage this function would: ``If all enumeration literals
5089 were covered by the case expressions, turn one of the expressions
5090 into the default expression since it should not be possible to fall
5091 through such a switch.''
5093 That code has since been removed as: ``This optimization is
5094 disabled because it causes valid programs to fail. ANSI C does not
5095 guarantee that an expression with enum type will have a value that
5096 is the same as one of the enumeration literals.'' */
5099 check_for_full_enumeration_handling (type)
5102 struct case_node *n;
5105 /* True iff the selector type is a numbered set mode. */
5108 /* The number of possible selector values. */
5111 /* For each possible selector value. a one iff it has been matched
5112 by a case value alternative. */
5113 unsigned char *cases_seen;
5115 /* The allocated size of cases_seen, in chars. */
5116 HOST_WIDE_INT bytes_needed;
5118 size = all_cases_count (type, &sparseness);
5119 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5121 if (size > 0 && size < 600000
5122 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5123 this optimization if we don't have enough memory rather than
5124 aborting, as xmalloc would do. */
5126 (unsigned char *) really_call_calloc (bytes_needed, 1)) != NULL)
5129 tree v = TYPE_VALUES (type);
5131 /* The time complexity of this code is normally O(N), where
5132 N being the number of members in the enumerated type.
5133 However, if type is an ENUMERAL_TYPE whose values do not
5134 increase monotonically, O(N*log(N)) time may be needed. */
5136 mark_seen_cases (type, cases_seen, size, sparseness);
5138 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5139 if (BITARRAY_TEST (cases_seen, i) == 0)
5140 warning ("enumeration value `%s' not handled in switch",
5141 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5146 /* Now we go the other way around; we warn if there are case
5147 expressions that don't correspond to enumerators. This can
5148 occur since C and C++ don't enforce type-checking of
5149 assignments to enumeration variables. */
5151 if (case_stack->data.case_stmt.case_list
5152 && case_stack->data.case_stmt.case_list->left)
5153 case_stack->data.case_stmt.case_list
5154 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5155 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5157 for (chain = TYPE_VALUES (type);
5158 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5159 chain = TREE_CHAIN (chain))
5164 if (TYPE_NAME (type) == 0)
5165 warning ("case value `%ld' not in enumerated type",
5166 (long) TREE_INT_CST_LOW (n->low));
5168 warning ("case value `%ld' not in enumerated type `%s'",
5169 (long) TREE_INT_CST_LOW (n->low),
5170 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5173 : DECL_NAME (TYPE_NAME (type))));
5175 if (!tree_int_cst_equal (n->low, n->high))
5177 for (chain = TYPE_VALUES (type);
5178 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5179 chain = TREE_CHAIN (chain))
5184 if (TYPE_NAME (type) == 0)
5185 warning ("case value `%ld' not in enumerated type",
5186 (long) TREE_INT_CST_LOW (n->high));
5188 warning ("case value `%ld' not in enumerated type `%s'",
5189 (long) TREE_INT_CST_LOW (n->high),
5190 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5193 : DECL_NAME (TYPE_NAME (type))));
5201 /* Terminate a case (Pascal) or switch (C) statement
5202 in which ORIG_INDEX is the expression to be tested.
5203 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5204 type as given in the source before any compiler conversions.
5205 Generate the code to test it and jump to the right place. */
5208 expand_end_case_type (orig_index, orig_type)
5209 tree orig_index, orig_type;
5211 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5212 rtx default_label = 0;
5213 struct case_node *n;
5220 rtx before_case, end;
5221 struct nesting *thiscase = case_stack;
5222 tree index_expr, index_type;
5225 /* Don't crash due to previous errors. */
5226 if (thiscase == NULL)
5229 table_label = gen_label_rtx ();
5230 index_expr = thiscase->data.case_stmt.index_expr;
5231 index_type = TREE_TYPE (index_expr);
5232 unsignedp = TREE_UNSIGNED (index_type);
5233 if (orig_type == NULL)
5234 orig_type = TREE_TYPE (orig_index);
5236 do_pending_stack_adjust ();
5238 /* This might get an spurious warning in the presence of a syntax error;
5239 it could be fixed by moving the call to check_seenlabel after the
5240 check for error_mark_node, and copying the code of check_seenlabel that
5241 deals with case_stack->data.case_stmt.line_number_status /
5242 restore_line_number_status in front of the call to end_cleanup_deferral;
5243 However, this might miss some useful warnings in the presence of
5244 non-syntax errors. */
5247 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5248 if (index_type != error_mark_node)
5250 /* If the switch expression was an enumerated type, check that
5251 exactly all enumeration literals are covered by the cases.
5252 The check is made when -Wswitch was specified and there is no
5253 default case, or when -Wswitch-enum was specified. */
5254 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5255 || warn_switch_enum)
5256 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5257 && TREE_CODE (index_expr) != INTEGER_CST)
5258 check_for_full_enumeration_handling (orig_type);
5260 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5261 warning ("switch missing default case");
5263 /* If we don't have a default-label, create one here,
5264 after the body of the switch. */
5265 if (thiscase->data.case_stmt.default_label == 0)
5267 thiscase->data.case_stmt.default_label
5268 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5269 expand_label (thiscase->data.case_stmt.default_label);
5271 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5273 before_case = get_last_insn ();
5275 if (thiscase->data.case_stmt.case_list
5276 && thiscase->data.case_stmt.case_list->left)
5277 thiscase->data.case_stmt.case_list
5278 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5280 /* Simplify the case-list before we count it. */
5281 group_case_nodes (thiscase->data.case_stmt.case_list);
5283 /* Get upper and lower bounds of case values.
5284 Also convert all the case values to the index expr's data type. */
5287 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5289 /* Check low and high label values are integers. */
5290 if (TREE_CODE (n->low) != INTEGER_CST)
5292 if (TREE_CODE (n->high) != INTEGER_CST)
5295 n->low = convert (index_type, n->low);
5296 n->high = convert (index_type, n->high);
5298 /* Count the elements and track the largest and smallest
5299 of them (treating them as signed even if they are not). */
5307 if (INT_CST_LT (n->low, minval))
5309 if (INT_CST_LT (maxval, n->high))
5312 /* A range counts double, since it requires two compares. */
5313 if (! tree_int_cst_equal (n->low, n->high))
5317 /* Compute span of values. */
5319 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5321 end_cleanup_deferral ();
5325 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5327 emit_jump (default_label);
5330 /* If range of values is much bigger than number of values,
5331 make a sequence of conditional branches instead of a dispatch.
5332 If the switch-index is a constant, do it this way
5333 because we can optimize it. */
5335 else if (count < case_values_threshold ()
5336 || compare_tree_int (range, 10 * count) > 0
5337 /* RANGE may be signed, and really large ranges will show up
5338 as negative numbers. */
5339 || compare_tree_int (range, 0) < 0
5340 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5343 || TREE_CODE (index_expr) == INTEGER_CST
5344 || (TREE_CODE (index_expr) == COMPOUND_EXPR
5345 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
5347 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5349 /* If the index is a short or char that we do not have
5350 an insn to handle comparisons directly, convert it to
5351 a full integer now, rather than letting each comparison
5352 generate the conversion. */
5354 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5355 && ! have_insn_for (COMPARE, GET_MODE (index)))
5357 enum machine_mode wider_mode;
5358 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5359 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5360 if (have_insn_for (COMPARE, wider_mode))
5362 index = convert_to_mode (wider_mode, index, unsignedp);
5368 do_pending_stack_adjust ();
5370 index = protect_from_queue (index, 0);
5371 if (GET_CODE (index) == MEM)
5372 index = copy_to_reg (index);
5373 if (GET_CODE (index) == CONST_INT
5374 || TREE_CODE (index_expr) == INTEGER_CST)
5376 /* Make a tree node with the proper constant value
5377 if we don't already have one. */
5378 if (TREE_CODE (index_expr) != INTEGER_CST)
5381 = build_int_2 (INTVAL (index),
5382 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5383 index_expr = convert (index_type, index_expr);
5386 /* For constant index expressions we need only
5387 issue an unconditional branch to the appropriate
5388 target code. The job of removing any unreachable
5389 code is left to the optimisation phase if the
5390 "-O" option is specified. */
5391 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5392 if (! tree_int_cst_lt (index_expr, n->low)
5393 && ! tree_int_cst_lt (n->high, index_expr))
5397 emit_jump (label_rtx (n->code_label));
5399 emit_jump (default_label);
5403 /* If the index expression is not constant we generate
5404 a binary decision tree to select the appropriate
5405 target code. This is done as follows:
5407 The list of cases is rearranged into a binary tree,
5408 nearly optimal assuming equal probability for each case.
5410 The tree is transformed into RTL, eliminating
5411 redundant test conditions at the same time.
5413 If program flow could reach the end of the
5414 decision tree an unconditional jump to the
5415 default code is emitted. */
5418 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5419 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5420 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5421 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5422 default_label, index_type);
5423 emit_jump_if_reachable (default_label);
5428 if (! try_casesi (index_type, index_expr, minval, range,
5429 table_label, default_label))
5431 index_type = thiscase->data.case_stmt.nominal_type;
5433 /* Index jumptables from zero for suitable values of
5434 minval to avoid a subtraction. */
5436 && compare_tree_int (minval, 0) > 0
5437 && compare_tree_int (minval, 3) < 0)
5439 minval = integer_zero_node;
5443 if (! try_tablejump (index_type, index_expr, minval, range,
5444 table_label, default_label))
5448 /* Get table of labels to jump to, in order of case index. */
5450 ncases = tree_low_cst (range, 0) + 1;
5451 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5452 memset ((char *) labelvec, 0, ncases * sizeof (rtx));
5454 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5456 /* Compute the low and high bounds relative to the minimum
5457 value since that should fit in a HOST_WIDE_INT while the
5458 actual values may not. */
5460 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5461 n->low, minval)), 1);
5462 HOST_WIDE_INT i_high
5463 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5464 n->high, minval)), 1);
5467 for (i = i_low; i <= i_high; i ++)
5469 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5472 /* Fill in the gaps with the default. */
5473 for (i = 0; i < ncases; i++)
5474 if (labelvec[i] == 0)
5475 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5477 /* Output the table */
5478 emit_label (table_label);
5480 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5481 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5482 gen_rtx_LABEL_REF (Pmode, table_label),
5483 gen_rtvec_v (ncases, labelvec),
5484 const0_rtx, const0_rtx));
5486 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5487 gen_rtvec_v (ncases, labelvec)));
5489 /* If the case insn drops through the table,
5490 after the table we must jump to the default-label.
5491 Otherwise record no drop-through after the table. */
5492 #ifdef CASE_DROPS_THROUGH
5493 emit_jump (default_label);
5499 before_case = NEXT_INSN (before_case);
5500 end = get_last_insn ();
5501 if (squeeze_notes (&before_case, &end))
5503 reorder_insns (before_case, end,
5504 thiscase->data.case_stmt.start);
5507 end_cleanup_deferral ();
5509 if (thiscase->exit_label)
5510 emit_label (thiscase->exit_label);
5512 POPSTACK (case_stack);
5517 /* Convert the tree NODE into a list linked by the right field, with the left
5518 field zeroed. RIGHT is used for recursion; it is a list to be placed
5519 rightmost in the resulting list. */
5521 static struct case_node *
5522 case_tree2list (node, right)
5523 struct case_node *node, *right;
5525 struct case_node *left;
5528 right = case_tree2list (node->right, right);
5530 node->right = right;
5531 if ((left = node->left))
5534 return case_tree2list (left, node);
5540 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5543 do_jump_if_equal (op1, op2, label, unsignedp)
5544 rtx op1, op2, label;
5547 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5549 if (INTVAL (op1) == INTVAL (op2))
5553 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5554 (GET_MODE (op1) == VOIDmode
5555 ? GET_MODE (op2) : GET_MODE (op1)),
5559 /* Not all case values are encountered equally. This function
5560 uses a heuristic to weight case labels, in cases where that
5561 looks like a reasonable thing to do.
5563 Right now, all we try to guess is text, and we establish the
5566 chars above space: 16
5575 If we find any cases in the switch that are not either -1 or in the range
5576 of valid ASCII characters, or are control characters other than those
5577 commonly used with "\", don't treat this switch scanning text.
5579 Return 1 if these nodes are suitable for cost estimation, otherwise
5583 estimate_case_costs (node)
5586 tree min_ascii = integer_minus_one_node;
5587 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5591 /* If we haven't already made the cost table, make it now. Note that the
5592 lower bound of the table is -1, not zero. */
5594 if (! cost_table_initialized)
5596 cost_table_initialized = 1;
5598 for (i = 0; i < 128; i++)
5601 COST_TABLE (i) = 16;
5602 else if (ISPUNCT (i))
5604 else if (ISCNTRL (i))
5605 COST_TABLE (i) = -1;
5608 COST_TABLE (' ') = 8;
5609 COST_TABLE ('\t') = 4;
5610 COST_TABLE ('\0') = 4;
5611 COST_TABLE ('\n') = 2;
5612 COST_TABLE ('\f') = 1;
5613 COST_TABLE ('\v') = 1;
5614 COST_TABLE ('\b') = 1;
5617 /* See if all the case expressions look like text. It is text if the
5618 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5619 as signed arithmetic since we don't want to ever access cost_table with a
5620 value less than -1. Also check that none of the constants in a range
5621 are strange control characters. */
5623 for (n = node; n; n = n->right)
5625 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5628 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5629 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5630 if (COST_TABLE (i) < 0)
5634 /* All interesting values are within the range of interesting
5635 ASCII characters. */
5639 /* Scan an ordered list of case nodes
5640 combining those with consecutive values or ranges.
5642 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5645 group_case_nodes (head)
5648 case_node_ptr node = head;
5652 rtx lb = next_real_insn (label_rtx (node->code_label));
5654 case_node_ptr np = node;
5656 /* Try to group the successors of NODE with NODE. */
5657 while (((np = np->right) != 0)
5658 /* Do they jump to the same place? */
5659 && ((lb2 = next_real_insn (label_rtx (np->code_label))) == lb
5660 || (lb != 0 && lb2 != 0
5661 && simplejump_p (lb)
5662 && simplejump_p (lb2)
5663 && rtx_equal_p (SET_SRC (PATTERN (lb)),
5664 SET_SRC (PATTERN (lb2)))))
5665 /* Are their ranges consecutive? */
5666 && tree_int_cst_equal (np->low,
5667 fold (build (PLUS_EXPR,
5668 TREE_TYPE (node->high),
5671 /* An overflow is not consecutive. */
5672 && tree_int_cst_lt (node->high,
5673 fold (build (PLUS_EXPR,
5674 TREE_TYPE (node->high),
5676 integer_one_node))))
5678 node->high = np->high;
5680 /* NP is the first node after NODE which can't be grouped with it.
5681 Delete the nodes in between, and move on to that node. */
5687 /* Take an ordered list of case nodes
5688 and transform them into a near optimal binary tree,
5689 on the assumption that any target code selection value is as
5690 likely as any other.
5692 The transformation is performed by splitting the ordered
5693 list into two equal sections plus a pivot. The parts are
5694 then attached to the pivot as left and right branches. Each
5695 branch is then transformed recursively. */
5698 balance_case_nodes (head, parent)
5699 case_node_ptr *head;
5700 case_node_ptr parent;
5713 /* Count the number of entries on branch. Also count the ranges. */
5717 if (!tree_int_cst_equal (np->low, np->high))
5721 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5725 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5733 /* Split this list if it is long enough for that to help. */
5738 /* Find the place in the list that bisects the list's total cost,
5739 Here I gets half the total cost. */
5744 /* Skip nodes while their cost does not reach that amount. */
5745 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5746 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5747 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5750 npp = &(*npp)->right;
5755 /* Leave this branch lopsided, but optimize left-hand
5756 side and fill in `parent' fields for right-hand side. */
5758 np->parent = parent;
5759 balance_case_nodes (&np->left, np);
5760 for (; np->right; np = np->right)
5761 np->right->parent = np;
5765 /* If there are just three nodes, split at the middle one. */
5767 npp = &(*npp)->right;
5770 /* Find the place in the list that bisects the list's total cost,
5771 where ranges count as 2.
5772 Here I gets half the total cost. */
5773 i = (i + ranges + 1) / 2;
5776 /* Skip nodes while their cost does not reach that amount. */
5777 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5782 npp = &(*npp)->right;
5787 np->parent = parent;
5790 /* Optimize each of the two split parts. */
5791 balance_case_nodes (&np->left, np);
5792 balance_case_nodes (&np->right, np);
5796 /* Else leave this branch as one level,
5797 but fill in `parent' fields. */
5799 np->parent = parent;
5800 for (; np->right; np = np->right)
5801 np->right->parent = np;
5806 /* Search the parent sections of the case node tree
5807 to see if a test for the lower bound of NODE would be redundant.
5808 INDEX_TYPE is the type of the index expression.
5810 The instructions to generate the case decision tree are
5811 output in the same order as nodes are processed so it is
5812 known that if a parent node checks the range of the current
5813 node minus one that the current node is bounded at its lower
5814 span. Thus the test would be redundant. */
5817 node_has_low_bound (node, index_type)
5822 case_node_ptr pnode;
5824 /* If the lower bound of this node is the lowest value in the index type,
5825 we need not test it. */
5827 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5830 /* If this node has a left branch, the value at the left must be less
5831 than that at this node, so it cannot be bounded at the bottom and
5832 we need not bother testing any further. */
5837 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5838 node->low, integer_one_node));
5840 /* If the subtraction above overflowed, we can't verify anything.
5841 Otherwise, look for a parent that tests our value - 1. */
5843 if (! tree_int_cst_lt (low_minus_one, node->low))
5846 for (pnode = node->parent; pnode; pnode = pnode->parent)
5847 if (tree_int_cst_equal (low_minus_one, pnode->high))
5853 /* Search the parent sections of the case node tree
5854 to see if a test for the upper bound of NODE would be redundant.
5855 INDEX_TYPE is the type of the index expression.
5857 The instructions to generate the case decision tree are
5858 output in the same order as nodes are processed so it is
5859 known that if a parent node checks the range of the current
5860 node plus one that the current node is bounded at its upper
5861 span. Thus the test would be redundant. */
5864 node_has_high_bound (node, index_type)
5869 case_node_ptr pnode;
5871 /* If there is no upper bound, obviously no test is needed. */
5873 if (TYPE_MAX_VALUE (index_type) == NULL)
5876 /* If the upper bound of this node is the highest value in the type
5877 of the index expression, we need not test against it. */
5879 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5882 /* If this node has a right branch, the value at the right must be greater
5883 than that at this node, so it cannot be bounded at the top and
5884 we need not bother testing any further. */
5889 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5890 node->high, integer_one_node));
5892 /* If the addition above overflowed, we can't verify anything.
5893 Otherwise, look for a parent that tests our value + 1. */
5895 if (! tree_int_cst_lt (node->high, high_plus_one))
5898 for (pnode = node->parent; pnode; pnode = pnode->parent)
5899 if (tree_int_cst_equal (high_plus_one, pnode->low))
5905 /* Search the parent sections of the
5906 case node tree to see if both tests for the upper and lower
5907 bounds of NODE would be redundant. */
5910 node_is_bounded (node, index_type)
5914 return (node_has_low_bound (node, index_type)
5915 && node_has_high_bound (node, index_type));
5918 /* Emit an unconditional jump to LABEL unless it would be dead code. */
5921 emit_jump_if_reachable (label)
5924 if (GET_CODE (get_last_insn ()) != BARRIER)
5928 /* Emit step-by-step code to select a case for the value of INDEX.
5929 The thus generated decision tree follows the form of the
5930 case-node binary tree NODE, whose nodes represent test conditions.
5931 INDEX_TYPE is the type of the index of the switch.
5933 Care is taken to prune redundant tests from the decision tree
5934 by detecting any boundary conditions already checked by
5935 emitted rtx. (See node_has_high_bound, node_has_low_bound
5936 and node_is_bounded, above.)
5938 Where the test conditions can be shown to be redundant we emit
5939 an unconditional jump to the target code. As a further
5940 optimization, the subordinates of a tree node are examined to
5941 check for bounded nodes. In this case conditional and/or
5942 unconditional jumps as a result of the boundary check for the
5943 current node are arranged to target the subordinates associated
5944 code for out of bound conditions on the current node.
5946 We can assume that when control reaches the code generated here,
5947 the index value has already been compared with the parents
5948 of this node, and determined to be on the same side of each parent
5949 as this node is. Thus, if this node tests for the value 51,
5950 and a parent tested for 52, we don't need to consider
5951 the possibility of a value greater than 51. If another parent
5952 tests for the value 50, then this node need not test anything. */
5955 emit_case_nodes (index, node, default_label, index_type)
5961 /* If INDEX has an unsigned type, we must make unsigned branches. */
5962 int unsignedp = TREE_UNSIGNED (index_type);
5963 enum machine_mode mode = GET_MODE (index);
5964 enum machine_mode imode = TYPE_MODE (index_type);
5966 /* See if our parents have already tested everything for us.
5967 If they have, emit an unconditional jump for this node. */
5968 if (node_is_bounded (node, index_type))
5969 emit_jump (label_rtx (node->code_label));
5971 else if (tree_int_cst_equal (node->low, node->high))
5973 /* Node is single valued. First see if the index expression matches
5974 this node and then check our children, if any. */
5976 do_jump_if_equal (index,
5977 convert_modes (mode, imode,
5978 expand_expr (node->low, NULL_RTX,
5981 label_rtx (node->code_label), unsignedp);
5983 if (node->right != 0 && node->left != 0)
5985 /* This node has children on both sides.
5986 Dispatch to one side or the other
5987 by comparing the index value with this node's value.
5988 If one subtree is bounded, check that one first,
5989 so we can avoid real branches in the tree. */
5991 if (node_is_bounded (node->right, index_type))
5993 emit_cmp_and_jump_insns (index,
5996 expand_expr (node->high, NULL_RTX,
5999 GT, NULL_RTX, mode, unsignedp,
6000 label_rtx (node->right->code_label));
6001 emit_case_nodes (index, node->left, default_label, index_type);
6004 else if (node_is_bounded (node->left, index_type))
6006 emit_cmp_and_jump_insns (index,
6009 expand_expr (node->high, NULL_RTX,
6012 LT, NULL_RTX, mode, unsignedp,
6013 label_rtx (node->left->code_label));
6014 emit_case_nodes (index, node->right, default_label, index_type);
6019 /* Neither node is bounded. First distinguish the two sides;
6020 then emit the code for one side at a time. */
6022 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6024 /* See if the value is on the right. */
6025 emit_cmp_and_jump_insns (index,
6028 expand_expr (node->high, NULL_RTX,
6031 GT, NULL_RTX, mode, unsignedp,
6032 label_rtx (test_label));
6034 /* Value must be on the left.
6035 Handle the left-hand subtree. */
6036 emit_case_nodes (index, node->left, default_label, index_type);
6037 /* If left-hand subtree does nothing,
6039 emit_jump_if_reachable (default_label);
6041 /* Code branches here for the right-hand subtree. */
6042 expand_label (test_label);
6043 emit_case_nodes (index, node->right, default_label, index_type);
6047 else if (node->right != 0 && node->left == 0)
6049 /* Here we have a right child but no left so we issue conditional
6050 branch to default and process the right child.
6052 Omit the conditional branch to default if we it avoid only one
6053 right child; it costs too much space to save so little time. */
6055 if (node->right->right || node->right->left
6056 || !tree_int_cst_equal (node->right->low, node->right->high))
6058 if (!node_has_low_bound (node, index_type))
6060 emit_cmp_and_jump_insns (index,
6063 expand_expr (node->high, NULL_RTX,
6066 LT, NULL_RTX, mode, unsignedp,
6070 emit_case_nodes (index, node->right, default_label, index_type);
6073 /* We cannot process node->right normally
6074 since we haven't ruled out the numbers less than
6075 this node's value. So handle node->right explicitly. */
6076 do_jump_if_equal (index,
6079 expand_expr (node->right->low, NULL_RTX,
6082 label_rtx (node->right->code_label), unsignedp);
6085 else if (node->right == 0 && node->left != 0)
6087 /* Just one subtree, on the left. */
6088 if (node->left->left || node->left->right
6089 || !tree_int_cst_equal (node->left->low, node->left->high))
6091 if (!node_has_high_bound (node, index_type))
6093 emit_cmp_and_jump_insns (index,
6096 expand_expr (node->high, NULL_RTX,
6099 GT, NULL_RTX, mode, unsignedp,
6103 emit_case_nodes (index, node->left, default_label, index_type);
6106 /* We cannot process node->left normally
6107 since we haven't ruled out the numbers less than
6108 this node's value. So handle node->left explicitly. */
6109 do_jump_if_equal (index,
6112 expand_expr (node->left->low, NULL_RTX,
6115 label_rtx (node->left->code_label), unsignedp);
6120 /* Node is a range. These cases are very similar to those for a single
6121 value, except that we do not start by testing whether this node
6122 is the one to branch to. */
6124 if (node->right != 0 && node->left != 0)
6126 /* Node has subtrees on both sides.
6127 If the right-hand subtree is bounded,
6128 test for it first, since we can go straight there.
6129 Otherwise, we need to make a branch in the control structure,
6130 then handle the two subtrees. */
6131 tree test_label = 0;
6133 if (node_is_bounded (node->right, index_type))
6134 /* Right hand node is fully bounded so we can eliminate any
6135 testing and branch directly to the target code. */
6136 emit_cmp_and_jump_insns (index,
6139 expand_expr (node->high, NULL_RTX,
6142 GT, NULL_RTX, mode, unsignedp,
6143 label_rtx (node->right->code_label));
6146 /* Right hand node requires testing.
6147 Branch to a label where we will handle it later. */
6149 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6150 emit_cmp_and_jump_insns (index,
6153 expand_expr (node->high, NULL_RTX,
6156 GT, NULL_RTX, mode, unsignedp,
6157 label_rtx (test_label));
6160 /* Value belongs to this node or to the left-hand subtree. */
6162 emit_cmp_and_jump_insns (index,
6165 expand_expr (node->low, NULL_RTX,
6168 GE, NULL_RTX, mode, unsignedp,
6169 label_rtx (node->code_label));
6171 /* Handle the left-hand subtree. */
6172 emit_case_nodes (index, node->left, default_label, index_type);
6174 /* If right node had to be handled later, do that now. */
6178 /* If the left-hand subtree fell through,
6179 don't let it fall into the right-hand subtree. */
6180 emit_jump_if_reachable (default_label);
6182 expand_label (test_label);
6183 emit_case_nodes (index, node->right, default_label, index_type);
6187 else if (node->right != 0 && node->left == 0)
6189 /* Deal with values to the left of this node,
6190 if they are possible. */
6191 if (!node_has_low_bound (node, index_type))
6193 emit_cmp_and_jump_insns (index,
6196 expand_expr (node->low, NULL_RTX,
6199 LT, NULL_RTX, mode, unsignedp,
6203 /* Value belongs to this node or to the right-hand subtree. */
6205 emit_cmp_and_jump_insns (index,
6208 expand_expr (node->high, NULL_RTX,
6211 LE, NULL_RTX, mode, unsignedp,
6212 label_rtx (node->code_label));
6214 emit_case_nodes (index, node->right, default_label, index_type);
6217 else if (node->right == 0 && node->left != 0)
6219 /* Deal with values to the right of this node,
6220 if they are possible. */
6221 if (!node_has_high_bound (node, index_type))
6223 emit_cmp_and_jump_insns (index,
6226 expand_expr (node->high, NULL_RTX,
6229 GT, NULL_RTX, mode, unsignedp,
6233 /* Value belongs to this node or to the left-hand subtree. */
6235 emit_cmp_and_jump_insns (index,
6238 expand_expr (node->low, NULL_RTX,
6241 GE, NULL_RTX, mode, unsignedp,
6242 label_rtx (node->code_label));
6244 emit_case_nodes (index, node->left, default_label, index_type);
6249 /* Node has no children so we check low and high bounds to remove
6250 redundant tests. Only one of the bounds can exist,
6251 since otherwise this node is bounded--a case tested already. */
6252 int high_bound = node_has_high_bound (node, index_type);
6253 int low_bound = node_has_low_bound (node, index_type);
6255 if (!high_bound && low_bound)
6257 emit_cmp_and_jump_insns (index,
6260 expand_expr (node->high, NULL_RTX,
6263 GT, NULL_RTX, mode, unsignedp,
6267 else if (!low_bound && high_bound)
6269 emit_cmp_and_jump_insns (index,
6272 expand_expr (node->low, NULL_RTX,
6275 LT, NULL_RTX, mode, unsignedp,
6278 else if (!low_bound && !high_bound)
6280 /* Widen LOW and HIGH to the same width as INDEX. */
6281 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6282 tree low = build1 (CONVERT_EXPR, type, node->low);
6283 tree high = build1 (CONVERT_EXPR, type, node->high);
6284 rtx low_rtx, new_index, new_bound;
6286 /* Instead of doing two branches, emit one unsigned branch for
6287 (index-low) > (high-low). */
6288 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6289 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6290 NULL_RTX, unsignedp,
6292 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6296 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6297 mode, 1, default_label);
6300 emit_jump (label_rtx (node->code_label));
6305 #include "gt-stmt.h"