1 /* Expands front end tree to back end RTL for GCC
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
38 #include "coretypes.h"
47 #include "insn-config.h"
50 #include "hard-reg-set.h"
57 #include "langhooks.h"
62 /* Assume that case vectors are not pc-relative. */
63 #ifndef CASE_VECTOR_PC_RELATIVE
64 #define CASE_VECTOR_PC_RELATIVE 0
67 /* Functions and data structures for expanding case statements. */
69 /* Case label structure, used to hold info on labels within case
70 statements. We handle "range" labels; for a single-value label
71 as in C, the high and low limits are the same.
73 An AVL tree of case nodes is initially created, and later transformed
74 to a list linked via the RIGHT fields in the nodes. Nodes with
75 higher case values are later in the list.
77 Switch statements can be output in one of two forms. A branch table
78 is used if there are more than a few labels and the labels are dense
79 within the range between the smallest and largest case value. If a
80 branch table is used, no further manipulations are done with the case
83 The alternative to the use of a branch table is to generate a series
84 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
85 and PARENT fields to hold a binary tree. Initially the tree is
86 totally unbalanced, with everything on the right. We balance the tree
87 with nodes on the left having lower case values than the parent
88 and nodes on the right having higher values. We then output the tree
91 struct case_node GTY(())
93 struct case_node *left; /* Left son in binary tree */
94 struct case_node *right; /* Right son in binary tree; also node chain */
95 struct case_node *parent; /* Parent of node in binary tree */
96 tree low; /* Lowest index value for this label */
97 tree high; /* Highest index value for this label */
98 tree code_label; /* Label to jump to when node matches */
102 typedef struct case_node case_node;
103 typedef struct case_node *case_node_ptr;
105 /* These are used by estimate_case_costs and balance_case_nodes. */
107 /* This must be a signed type, and non-ANSI compilers lack signed char. */
108 static short cost_table_[129];
109 static int use_cost_table;
110 static int cost_table_initialized;
112 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
114 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
116 /* Stack of control and binding constructs we are currently inside.
118 These constructs begin when you call `expand_start_WHATEVER'
119 and end when you call `expand_end_WHATEVER'. This stack records
120 info about how the construct began that tells the end-function
121 what to do. It also may provide information about the construct
122 to alter the behavior of other constructs within the body.
123 For example, they may affect the behavior of C `break' and `continue'.
125 Each construct gets one `struct nesting' object.
126 All of these objects are chained through the `all' field.
127 `nesting_stack' points to the first object (innermost construct).
128 The position of an entry on `nesting_stack' is in its `depth' field.
130 Each type of construct has its own individual stack.
131 For example, loops have `loop_stack'. Each object points to the
132 next object of the same type through the `next' field.
134 Some constructs are visible to `break' exit-statements and others
135 are not. Which constructs are visible depends on the language.
136 Therefore, the data structure allows each construct to be visible
137 or not, according to the args given when the construct is started.
138 The construct is visible if the `exit_label' field is non-null.
139 In that case, the value should be a CODE_LABEL rtx. */
141 struct nesting GTY(())
144 struct nesting *next;
155 /* For conds (if-then and if-then-else statements). */
158 /* Label for the end of the if construct.
159 There is none if EXITFLAG was not set
160 and no `else' has been seen yet. */
162 /* Label for the end of this alternative.
163 This may be the end of the if or the next else/elseif. */
165 } GTY ((tag ("COND_NESTING"))) cond;
169 /* Label at the top of the loop; place to loop back to. */
171 /* Label at the end of the whole construct. */
173 /* Label for `continue' statement to jump to;
174 this is in front of the stepper of the loop. */
176 } GTY ((tag ("LOOP_NESTING"))) loop;
177 /* For variable binding contours. */
180 /* Sequence number of this binding contour within the function,
181 in order of entry. */
182 int block_start_count;
183 /* Nonzero => value to restore stack to on exit. */
185 /* The NOTE that starts this contour.
186 Used by expand_goto to check whether the destination
187 is within each contour or not. */
189 /* Innermost containing binding contour that has a stack level. */
190 struct nesting *innermost_stack_block;
191 /* List of cleanups to be run on exit from this contour.
192 This is a list of expressions to be evaluated.
193 The TREE_PURPOSE of each link is the ..._DECL node
194 which the cleanup pertains to. */
196 /* List of cleanup-lists of blocks containing this block,
197 as they were at the locus where this block appears.
198 There is an element for each containing block,
199 ordered innermost containing block first.
200 The tail of this list can be 0,
201 if all remaining elements would be empty lists.
202 The element's TREE_VALUE is the cleanup-list of that block,
203 which may be null. */
205 /* Chain of labels defined inside this binding contour.
206 For contours that have stack levels or cleanups. */
207 struct label_chain *label_chain;
208 /* Nonzero if this is associated with an EH region. */
209 int exception_region;
210 /* The saved target_temp_slot_level from our outer block.
211 We may reset target_temp_slot_level to be the level of
212 this block, if that is done, target_temp_slot_level
213 reverts to the saved target_temp_slot_level at the very
215 int block_target_temp_slot_level;
216 /* True if we are currently emitting insns in an area of
217 output code that is controlled by a conditional
218 expression. This is used by the cleanup handling code to
219 generate conditional cleanup actions. */
220 int conditional_code;
221 /* A place to move the start of the exception region for any
222 of the conditional cleanups, must be at the end or after
223 the start of the last unconditional cleanup, and before any
224 conditional branch points. */
225 rtx last_unconditional_cleanup;
226 } GTY ((tag ("BLOCK_NESTING"))) block;
227 /* For switch (C) or case (Pascal) statements,
228 and also for dummies (see `expand_start_case_dummy'). */
231 /* The insn after which the case dispatch should finally
232 be emitted. Zero for a dummy. */
234 /* A list of case labels; it is first built as an AVL tree.
235 During expand_end_case, this is converted to a list, and may be
236 rearranged into a nearly balanced binary tree. */
237 struct case_node *case_list;
238 /* Label to jump to if no case matches. */
240 /* The expression to be dispatched on. */
242 /* Type that INDEX_EXPR should be converted to. */
244 /* Name of this kind of statement, for warnings. */
245 const char *printname;
246 /* Used to save no_line_numbers till we see the first case label.
247 We set this to -1 when we see the first case label in this
249 int line_number_status;
250 } GTY ((tag ("CASE_NESTING"))) case_stmt;
251 } GTY ((desc ("%1.desc"))) data;
254 /* Allocate and return a new `struct nesting'. */
256 #define ALLOC_NESTING() ggc_alloc (sizeof (struct nesting))
258 /* Pop the nesting stack element by element until we pop off
259 the element which is at the top of STACK.
260 Update all the other stacks, popping off elements from them
261 as we pop them from nesting_stack. */
263 #define POPSTACK(STACK) \
264 do { struct nesting *target = STACK; \
265 struct nesting *this; \
266 do { this = nesting_stack; \
267 if (loop_stack == this) \
268 loop_stack = loop_stack->next; \
269 if (cond_stack == this) \
270 cond_stack = cond_stack->next; \
271 if (block_stack == this) \
272 block_stack = block_stack->next; \
273 if (stack_block_stack == this) \
274 stack_block_stack = stack_block_stack->next; \
275 if (case_stack == this) \
276 case_stack = case_stack->next; \
277 nesting_depth = nesting_stack->depth - 1; \
278 nesting_stack = this->all; } \
279 while (this != target); } while (0)
281 /* In some cases it is impossible to generate code for a forward goto
282 until the label definition is seen. This happens when it may be necessary
283 for the goto to reset the stack pointer: we don't yet know how to do that.
284 So expand_goto puts an entry on this fixup list.
285 Each time a binding contour that resets the stack is exited,
287 If the target label has now been defined, we can insert the proper code. */
289 struct goto_fixup GTY(())
291 /* Points to following fixup. */
292 struct goto_fixup *next;
293 /* Points to the insn before the jump insn.
294 If more code must be inserted, it goes after this insn. */
296 /* The LABEL_DECL that this jump is jumping to, or 0
297 for break, continue or return. */
299 /* The BLOCK for the place where this goto was found. */
301 /* The CODE_LABEL rtx that this is jumping to. */
303 /* Number of binding contours started in current function
304 before the label reference. */
305 int block_start_count;
306 /* The outermost stack level that should be restored for this jump.
307 Each time a binding contour that resets the stack is exited,
308 if the target label is *not* yet defined, this slot is updated. */
310 /* List of lists of cleanup expressions to be run by this goto.
311 There is one element for each block that this goto is within.
312 The tail of this list can be 0,
313 if all remaining elements would be empty.
314 The TREE_VALUE contains the cleanup list of that block as of the
315 time this goto was seen.
316 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
317 tree cleanup_list_list;
320 /* Within any binding contour that must restore a stack level,
321 all labels are recorded with a chain of these structures. */
323 struct label_chain GTY(())
325 /* Points to following fixup. */
326 struct label_chain *next;
330 struct stmt_status GTY(())
332 /* Chain of all pending binding contours. */
333 struct nesting * x_block_stack;
335 /* If any new stacks are added here, add them to POPSTACKS too. */
337 /* Chain of all pending binding contours that restore stack levels
339 struct nesting * x_stack_block_stack;
341 /* Chain of all pending conditional statements. */
342 struct nesting * x_cond_stack;
344 /* Chain of all pending loops. */
345 struct nesting * x_loop_stack;
347 /* Chain of all pending case or switch statements. */
348 struct nesting * x_case_stack;
350 /* Separate chain including all of the above,
351 chained through the `all' field. */
352 struct nesting * x_nesting_stack;
354 /* Number of entries on nesting_stack now. */
357 /* Number of binding contours started so far in this function. */
358 int x_block_start_count;
360 /* Each time we expand an expression-statement,
361 record the expr's type and its RTL value here. */
362 tree x_last_expr_type;
363 rtx x_last_expr_value;
365 /* Nonzero if within a ({...}) grouping, in which case we must
366 always compute a value for each expr-stmt in case it is the last one. */
367 int x_expr_stmts_for_value;
369 /* Location of last line-number note, whether we actually
370 emitted it or not. */
371 location_t x_emit_locus;
373 struct goto_fixup *x_goto_fixup_chain;
376 #define block_stack (cfun->stmt->x_block_stack)
377 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
378 #define cond_stack (cfun->stmt->x_cond_stack)
379 #define loop_stack (cfun->stmt->x_loop_stack)
380 #define case_stack (cfun->stmt->x_case_stack)
381 #define nesting_stack (cfun->stmt->x_nesting_stack)
382 #define nesting_depth (cfun->stmt->x_nesting_depth)
383 #define current_block_start_count (cfun->stmt->x_block_start_count)
384 #define last_expr_type (cfun->stmt->x_last_expr_type)
385 #define last_expr_value (cfun->stmt->x_last_expr_value)
386 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
387 #define emit_locus (cfun->stmt->x_emit_locus)
388 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
390 /* Nonzero if we are using EH to handle cleanups. */
391 static int using_eh_for_cleanups_p = 0;
393 static int n_occurrences (int, const char *);
394 static bool parse_input_constraint (const char **, int, int, int, int,
395 const char * const *, bool *, bool *);
396 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
397 static void expand_goto_internal (tree, rtx, rtx);
398 static int expand_fixup (tree, rtx, rtx);
399 static rtx expand_nl_handler_label (rtx, rtx);
400 static void expand_nl_goto_receiver (void);
401 static void expand_nl_goto_receivers (struct nesting *);
402 static void fixup_gotos (struct nesting *, rtx, tree, rtx, int);
403 static bool check_operand_nalternatives (tree, tree);
404 static bool check_unique_operand_names (tree, tree);
405 static char *resolve_operand_name_1 (char *, tree, tree);
406 static void expand_null_return_1 (rtx);
407 static enum br_predictor return_prediction (rtx);
408 static void expand_value_return (rtx);
409 static int tail_recursion_args (tree, tree);
410 static void expand_cleanups (tree, int, int);
411 static void check_seenlabel (void);
412 static void do_jump_if_equal (rtx, rtx, rtx, int);
413 static int estimate_case_costs (case_node_ptr);
414 static bool same_case_target_p (rtx, rtx);
415 static void strip_default_case_nodes (case_node_ptr *, rtx);
416 static bool lshift_cheap_p (void);
417 static int case_bit_test_cmp (const void *, const void *);
418 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
419 static void group_case_nodes (case_node_ptr);
420 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
421 static int node_has_low_bound (case_node_ptr, tree);
422 static int node_has_high_bound (case_node_ptr, tree);
423 static int node_is_bounded (case_node_ptr, tree);
424 static void emit_jump_if_reachable (rtx);
425 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
426 static struct case_node *case_tree2list (case_node *, case_node *);
429 using_eh_for_cleanups (void)
431 using_eh_for_cleanups_p = 1;
435 init_stmt_for_function (void)
437 cfun->stmt = ggc_alloc_cleared (sizeof (struct stmt_status));
440 /* Record the current file and line. Called from emit_line_note. */
443 set_file_and_line_for_stmt (location_t location)
445 /* If we're outputting an inline function, and we add a line note,
446 there may be no CFUN->STMT information. So, there's no need to
449 emit_locus = location;
452 /* Emit a no-op instruction. */
459 last_insn = get_last_insn ();
461 && (GET_CODE (last_insn) == CODE_LABEL
462 || (GET_CODE (last_insn) == NOTE
463 && prev_real_insn (last_insn) == 0)))
464 emit_insn (gen_nop ());
467 /* Return the rtx-label that corresponds to a LABEL_DECL,
468 creating it if necessary. */
471 label_rtx (tree label)
473 if (TREE_CODE (label) != LABEL_DECL)
476 if (!DECL_RTL_SET_P (label))
477 SET_DECL_RTL (label, gen_label_rtx ());
479 return DECL_RTL (label);
482 /* As above, but also put it on the forced-reference list of the
483 function that contains it. */
485 force_label_rtx (tree label)
487 rtx ref = label_rtx (label);
488 tree function = decl_function_context (label);
494 if (function != current_function_decl
495 && function != inline_function_decl)
496 p = find_function_data (function);
500 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
501 p->expr->x_forced_labels);
505 /* Add an unconditional jump to LABEL as the next sequential instruction. */
508 emit_jump (rtx label)
510 do_pending_stack_adjust ();
511 emit_jump_insn (gen_jump (label));
515 /* Emit code to jump to the address
516 specified by the pointer expression EXP. */
519 expand_computed_goto (tree exp)
521 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
523 x = convert_memory_address (Pmode, x);
527 if (! cfun->computed_goto_common_label)
529 cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
530 cfun->computed_goto_common_label = gen_label_rtx ();
531 emit_label (cfun->computed_goto_common_label);
533 do_pending_stack_adjust ();
534 emit_indirect_jump (cfun->computed_goto_common_reg);
536 current_function_has_computed_jump = 1;
540 emit_move_insn (cfun->computed_goto_common_reg, x);
541 emit_jump (cfun->computed_goto_common_label);
545 /* Handle goto statements and the labels that they can go to. */
547 /* Specify the location in the RTL code of a label LABEL,
548 which is a LABEL_DECL tree node.
550 This is used for the kind of label that the user can jump to with a
551 goto statement, and for alternatives of a switch or case statement.
552 RTL labels generated for loops and conditionals don't go through here;
553 they are generated directly at the RTL level, by other functions below.
555 Note that this has nothing to do with defining label *names*.
556 Languages vary in how they do that and what that even means. */
559 expand_label (tree label)
561 struct label_chain *p;
563 do_pending_stack_adjust ();
564 emit_label (label_rtx (label));
565 if (DECL_NAME (label))
566 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
568 if (stack_block_stack != 0)
570 p = ggc_alloc (sizeof (struct label_chain));
571 p->next = stack_block_stack->data.block.label_chain;
572 stack_block_stack->data.block.label_chain = p;
577 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
578 from nested functions. */
581 declare_nonlocal_label (tree label)
583 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
585 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
586 LABEL_PRESERVE_P (label_rtx (label)) = 1;
587 if (nonlocal_goto_handler_slots == 0)
589 emit_stack_save (SAVE_NONLOCAL,
590 &nonlocal_goto_stack_level,
591 PREV_INSN (tail_recursion_reentry));
593 nonlocal_goto_handler_slots
594 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
597 /* Generate RTL code for a `goto' statement with target label LABEL.
598 LABEL should be a LABEL_DECL tree node that was or will later be
599 defined with `expand_label'. */
602 expand_goto (tree label)
606 /* Check for a nonlocal goto to a containing function. */
607 context = decl_function_context (label);
608 if (context != 0 && context != current_function_decl)
610 struct function *p = find_function_data (context);
611 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
612 rtx handler_slot, static_chain, save_area, insn;
615 /* Find the corresponding handler slot for this label. */
616 handler_slot = p->x_nonlocal_goto_handler_slots;
617 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
618 link = TREE_CHAIN (link))
619 handler_slot = XEXP (handler_slot, 1);
620 handler_slot = XEXP (handler_slot, 0);
622 p->has_nonlocal_label = 1;
623 current_function_has_nonlocal_goto = 1;
624 LABEL_REF_NONLOCAL_P (label_ref) = 1;
626 /* Copy the rtl for the slots so that they won't be shared in
627 case the virtual stack vars register gets instantiated differently
628 in the parent than in the child. */
630 static_chain = copy_to_reg (lookup_static_chain (label));
632 /* Get addr of containing function's current nonlocal goto handler,
633 which will do any cleanups and then jump to the label. */
634 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
635 virtual_stack_vars_rtx,
638 /* Get addr of containing function's nonlocal save area. */
639 save_area = p->x_nonlocal_goto_stack_level;
641 save_area = replace_rtx (copy_rtx (save_area),
642 virtual_stack_vars_rtx, static_chain);
644 #if HAVE_nonlocal_goto
645 if (HAVE_nonlocal_goto)
646 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
647 save_area, label_ref));
651 /* Restore frame pointer for containing function.
652 This sets the actual hard register used for the frame pointer
653 to the location of the function's incoming static chain info.
654 The non-local goto handler will then adjust it to contain the
655 proper value and reload the argument pointer, if needed. */
656 emit_move_insn (hard_frame_pointer_rtx, static_chain);
657 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
659 /* USE of hard_frame_pointer_rtx added for consistency;
660 not clear if really needed. */
661 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
662 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
663 emit_indirect_jump (handler_slot);
666 /* Search backwards to the jump insn and mark it as a
668 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
670 if (GET_CODE (insn) == JUMP_INSN)
672 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
673 const0_rtx, REG_NOTES (insn));
676 else if (GET_CODE (insn) == CALL_INSN)
681 expand_goto_internal (label, label_rtx (label), NULL_RTX);
684 /* Generate RTL code for a `goto' statement with target label BODY.
685 LABEL should be a LABEL_REF.
686 LAST_INSN, if non-0, is the rtx we should consider as the last
687 insn emitted (for the purposes of cleaning up a return). */
690 expand_goto_internal (tree body, rtx label, rtx last_insn)
692 struct nesting *block;
695 if (GET_CODE (label) != CODE_LABEL)
698 /* If label has already been defined, we can tell now
699 whether and how we must alter the stack level. */
701 if (PREV_INSN (label) != 0)
703 /* Find the innermost pending block that contains the label.
704 (Check containment by comparing insn-uids.)
705 Then restore the outermost stack level within that block,
706 and do cleanups of all blocks contained in it. */
707 for (block = block_stack; block; block = block->next)
709 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
711 if (block->data.block.stack_level != 0)
712 stack_level = block->data.block.stack_level;
713 /* Execute the cleanups for blocks we are exiting. */
714 if (block->data.block.cleanups != 0)
716 expand_cleanups (block->data.block.cleanups, 1, 1);
717 do_pending_stack_adjust ();
723 /* Ensure stack adjust isn't done by emit_jump, as this
724 would clobber the stack pointer. This one should be
725 deleted as dead by flow. */
726 clear_pending_stack_adjust ();
727 do_pending_stack_adjust ();
729 /* Don't do this adjust if it's to the end label and this function
730 is to return with a depressed stack pointer. */
731 if (label == return_label
732 && (((TREE_CODE (TREE_TYPE (current_function_decl))
734 && (TYPE_RETURNS_STACK_DEPRESSED
735 (TREE_TYPE (current_function_decl))))))
738 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
741 if (body != 0 && DECL_TOO_LATE (body))
742 error ("jump to `%s' invalidly jumps into binding contour",
743 IDENTIFIER_POINTER (DECL_NAME (body)));
745 /* Label not yet defined: may need to put this goto
746 on the fixup list. */
747 else if (! expand_fixup (body, label, last_insn))
749 /* No fixup needed. Record that the label is the target
750 of at least one goto that has no fixup. */
752 TREE_ADDRESSABLE (body) = 1;
758 /* Generate if necessary a fixup for a goto
759 whose target label in tree structure (if any) is TREE_LABEL
760 and whose target in rtl is RTL_LABEL.
762 If LAST_INSN is nonzero, we pretend that the jump appears
763 after insn LAST_INSN instead of at the current point in the insn stream.
765 The fixup will be used later to insert insns just before the goto.
766 Those insns will restore the stack level as appropriate for the
767 target label, and will (in the case of C++) also invoke any object
768 destructors which have to be invoked when we exit the scopes which
769 are exited by the goto.
771 Value is nonzero if a fixup is made. */
774 expand_fixup (tree tree_label, rtx rtl_label, rtx last_insn)
776 struct nesting *block, *end_block;
778 /* See if we can recognize which block the label will be output in.
779 This is possible in some very common cases.
780 If we succeed, set END_BLOCK to that block.
781 Otherwise, set it to 0. */
784 && (rtl_label == cond_stack->data.cond.endif_label
785 || rtl_label == cond_stack->data.cond.next_label))
786 end_block = cond_stack;
787 /* If we are in a loop, recognize certain labels which
788 are likely targets. This reduces the number of fixups
789 we need to create. */
791 && (rtl_label == loop_stack->data.loop.start_label
792 || rtl_label == loop_stack->data.loop.end_label
793 || rtl_label == loop_stack->data.loop.continue_label))
794 end_block = loop_stack;
798 /* Now set END_BLOCK to the binding level to which we will return. */
802 struct nesting *next_block = end_block->all;
805 /* First see if the END_BLOCK is inside the innermost binding level.
806 If so, then no cleanups or stack levels are relevant. */
807 while (next_block && next_block != block)
808 next_block = next_block->all;
813 /* Otherwise, set END_BLOCK to the innermost binding level
814 which is outside the relevant control-structure nesting. */
815 next_block = block_stack->next;
816 for (block = block_stack; block != end_block; block = block->all)
817 if (block == next_block)
818 next_block = next_block->next;
819 end_block = next_block;
822 /* Does any containing block have a stack level or cleanups?
823 If not, no fixup is needed, and that is the normal case
824 (the only case, for standard C). */
825 for (block = block_stack; block != end_block; block = block->next)
826 if (block->data.block.stack_level != 0
827 || block->data.block.cleanups != 0)
830 if (block != end_block)
832 /* Ok, a fixup is needed. Add a fixup to the list of such. */
833 struct goto_fixup *fixup = ggc_alloc (sizeof (struct goto_fixup));
834 /* In case an old stack level is restored, make sure that comes
835 after any pending stack adjust. */
836 /* ?? If the fixup isn't to come at the present position,
837 doing the stack adjust here isn't useful. Doing it with our
838 settings at that location isn't useful either. Let's hope
841 do_pending_stack_adjust ();
842 fixup->target = tree_label;
843 fixup->target_rtl = rtl_label;
845 /* Create a BLOCK node and a corresponding matched set of
846 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
847 this point. The notes will encapsulate any and all fixup
848 code which we might later insert at this point in the insn
849 stream. Also, the BLOCK node will be the parent (i.e. the
850 `SUPERBLOCK') of any other BLOCK nodes which we might create
851 later on when we are expanding the fixup code.
853 Note that optimization passes (including expand_end_loop)
854 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
858 rtx original_before_jump
859 = last_insn ? last_insn : get_last_insn ();
864 block = make_node (BLOCK);
865 TREE_USED (block) = 1;
867 if (!cfun->x_whole_function_mode_p)
868 (*lang_hooks.decls.insert_block) (block);
872 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
873 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
878 start = emit_note (NOTE_INSN_BLOCK_BEG);
879 if (cfun->x_whole_function_mode_p)
880 NOTE_BLOCK (start) = block;
881 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
882 end = emit_note (NOTE_INSN_BLOCK_END);
883 if (cfun->x_whole_function_mode_p)
884 NOTE_BLOCK (end) = block;
885 fixup->context = block;
887 emit_insn_after (start, original_before_jump);
890 fixup->block_start_count = current_block_start_count;
891 fixup->stack_level = 0;
892 fixup->cleanup_list_list
893 = ((block->data.block.outer_cleanups
894 || block->data.block.cleanups)
895 ? tree_cons (NULL_TREE, block->data.block.cleanups,
896 block->data.block.outer_cleanups)
898 fixup->next = goto_fixup_chain;
899 goto_fixup_chain = fixup;
905 /* Expand any needed fixups in the outputmost binding level of the
906 function. FIRST_INSN is the first insn in the function. */
909 expand_fixups (rtx first_insn)
911 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
914 /* When exiting a binding contour, process all pending gotos requiring fixups.
915 THISBLOCK is the structure that describes the block being exited.
916 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
917 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
918 FIRST_INSN is the insn that began this contour.
920 Gotos that jump out of this contour must restore the
921 stack level and do the cleanups before actually jumping.
923 DONT_JUMP_IN positive means report error if there is a jump into this
924 contour from before the beginning of the contour. This is also done if
925 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
928 fixup_gotos (struct nesting *thisblock, rtx stack_level,
929 tree cleanup_list, rtx first_insn, int dont_jump_in)
931 struct goto_fixup *f, *prev;
933 /* F is the fixup we are considering; PREV is the previous one. */
934 /* We run this loop in two passes so that cleanups of exited blocks
935 are run first, and blocks that are exited are marked so
938 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
940 /* Test for a fixup that is inactive because it is already handled. */
941 if (f->before_jump == 0)
943 /* Delete inactive fixup from the chain, if that is easy to do. */
945 prev->next = f->next;
947 /* Has this fixup's target label been defined?
948 If so, we can finalize it. */
949 else if (PREV_INSN (f->target_rtl) != 0)
953 /* If this fixup jumped into this contour from before the beginning
954 of this contour, report an error. This code used to use
955 the first non-label insn after f->target_rtl, but that's
956 wrong since such can be added, by things like put_var_into_stack
957 and have INSN_UIDs that are out of the range of the block. */
958 /* ??? Bug: this does not detect jumping in through intermediate
959 blocks that have stack levels or cleanups.
960 It detects only a problem with the innermost block
963 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
965 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
966 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
967 && ! DECL_ERROR_ISSUED (f->target))
969 error ("%Jlabel '%D' used before containing binding contour",
970 f->target, f->target);
971 /* Prevent multiple errors for one label. */
972 DECL_ERROR_ISSUED (f->target) = 1;
975 /* We will expand the cleanups into a sequence of their own and
976 then later on we will attach this new sequence to the insn
977 stream just ahead of the actual jump insn. */
981 /* Temporarily restore the lexical context where we will
982 logically be inserting the fixup code. We do this for the
983 sake of getting the debugging information right. */
985 (*lang_hooks.decls.pushlevel) (0);
986 (*lang_hooks.decls.set_block) (f->context);
988 /* Expand the cleanups for blocks this jump exits. */
989 if (f->cleanup_list_list)
992 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
993 /* Marked elements correspond to blocks that have been closed.
994 Do their cleanups. */
995 if (TREE_ADDRESSABLE (lists)
996 && TREE_VALUE (lists) != 0)
998 expand_cleanups (TREE_VALUE (lists), 1, 1);
999 /* Pop any pushes done in the cleanups,
1000 in case function is about to return. */
1001 do_pending_stack_adjust ();
1005 /* Restore stack level for the biggest contour that this
1006 jump jumps out of. */
1008 && ! (f->target_rtl == return_label
1009 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1011 && (TYPE_RETURNS_STACK_DEPRESSED
1012 (TREE_TYPE (current_function_decl))))))
1013 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1015 /* Finish up the sequence containing the insns which implement the
1016 necessary cleanups, and then attach that whole sequence to the
1017 insn stream just ahead of the actual jump insn. Attaching it
1018 at that point insures that any cleanups which are in fact
1019 implicit C++ object destructions (which must be executed upon
1020 leaving the block) appear (to the debugger) to be taking place
1021 in an area of the generated code where the object(s) being
1022 destructed are still "in scope". */
1024 cleanup_insns = get_insns ();
1025 (*lang_hooks.decls.poplevel) (1, 0, 0);
1028 emit_insn_after (cleanup_insns, f->before_jump);
1034 /* For any still-undefined labels, do the cleanups for this block now.
1035 We must do this now since items in the cleanup list may go out
1036 of scope when the block ends. */
1037 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1038 if (f->before_jump != 0
1039 && PREV_INSN (f->target_rtl) == 0
1040 /* Label has still not appeared. If we are exiting a block with
1041 a stack level to restore, that started before the fixup,
1042 mark this stack level as needing restoration
1043 when the fixup is later finalized. */
1045 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1046 means the label is undefined. That's erroneous, but possible. */
1047 && (thisblock->data.block.block_start_count
1048 <= f->block_start_count))
1050 tree lists = f->cleanup_list_list;
1053 for (; lists; lists = TREE_CHAIN (lists))
1054 /* If the following elt. corresponds to our containing block
1055 then the elt. must be for this block. */
1056 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1059 (*lang_hooks.decls.pushlevel) (0);
1060 (*lang_hooks.decls.set_block) (f->context);
1061 expand_cleanups (TREE_VALUE (lists), 1, 1);
1062 do_pending_stack_adjust ();
1063 cleanup_insns = get_insns ();
1064 (*lang_hooks.decls.poplevel) (1, 0, 0);
1066 if (cleanup_insns != 0)
1068 = emit_insn_after (cleanup_insns, f->before_jump);
1070 f->cleanup_list_list = TREE_CHAIN (lists);
1074 f->stack_level = stack_level;
1078 /* Return the number of times character C occurs in string S. */
1080 n_occurrences (int c, const char *s)
1088 /* Generate RTL for an asm statement (explicit assembler code).
1089 STRING is a STRING_CST node containing the assembler code text,
1090 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
1091 insn is volatile; don't optimize it. */
1094 expand_asm (tree string, int vol)
1098 if (TREE_CODE (string) == ADDR_EXPR)
1099 string = TREE_OPERAND (string, 0);
1101 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
1103 MEM_VOLATILE_P (body) = vol;
1110 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1111 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1112 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1113 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1114 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1115 constraint allows the use of a register operand. And, *IS_INOUT
1116 will be true if the operand is read-write, i.e., if it is used as
1117 an input as well as an output. If *CONSTRAINT_P is not in
1118 canonical form, it will be made canonical. (Note that `+' will be
1119 replaced with `=' as part of this process.)
1121 Returns TRUE if all went well; FALSE if an error occurred. */
1124 parse_output_constraint (const char **constraint_p, int operand_num,
1125 int ninputs, int noutputs, bool *allows_mem,
1126 bool *allows_reg, bool *is_inout)
1128 const char *constraint = *constraint_p;
1131 /* Assume the constraint doesn't allow the use of either a register
1133 *allows_mem = false;
1134 *allows_reg = false;
1136 /* Allow the `=' or `+' to not be at the beginning of the string,
1137 since it wasn't explicitly documented that way, and there is a
1138 large body of code that puts it last. Swap the character to
1139 the front, so as not to uglify any place else. */
1140 p = strchr (constraint, '=');
1142 p = strchr (constraint, '+');
1144 /* If the string doesn't contain an `=', issue an error
1148 error ("output operand constraint lacks `='");
1152 /* If the constraint begins with `+', then the operand is both read
1153 from and written to. */
1154 *is_inout = (*p == '+');
1156 /* Canonicalize the output constraint so that it begins with `='. */
1157 if (p != constraint || is_inout)
1160 size_t c_len = strlen (constraint);
1162 if (p != constraint)
1163 warning ("output constraint `%c' for operand %d is not at the beginning",
1166 /* Make a copy of the constraint. */
1167 buf = alloca (c_len + 1);
1168 strcpy (buf, constraint);
1169 /* Swap the first character and the `=' or `+'. */
1170 buf[p - constraint] = buf[0];
1171 /* Make sure the first character is an `='. (Until we do this,
1172 it might be a `+'.) */
1174 /* Replace the constraint with the canonicalized string. */
1175 *constraint_p = ggc_alloc_string (buf, c_len);
1176 constraint = *constraint_p;
1179 /* Loop through the constraint string. */
1180 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1185 error ("operand constraint contains incorrectly positioned '+' or '='");
1189 if (operand_num + 1 == ninputs + noutputs)
1191 error ("`%%' constraint used with last operand");
1196 case 'V': case 'm': case 'o':
1200 case '?': case '!': case '*': case '&': case '#':
1201 case 'E': case 'F': case 'G': case 'H':
1202 case 's': case 'i': case 'n':
1203 case 'I': case 'J': case 'K': case 'L': case 'M':
1204 case 'N': case 'O': case 'P': case ',':
1207 case '0': case '1': case '2': case '3': case '4':
1208 case '5': case '6': case '7': case '8': case '9':
1210 error ("matching constraint not valid in output operand");
1214 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1215 excepting those that expand_call created. So match memory
1232 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1234 #ifdef EXTRA_CONSTRAINT_STR
1235 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1237 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1241 /* Otherwise we can't assume anything about the nature of
1242 the constraint except that it isn't purely registers.
1243 Treat it like "g" and hope for the best. */
1254 /* Similar, but for input constraints. */
1257 parse_input_constraint (const char **constraint_p, int input_num,
1258 int ninputs, int noutputs, int ninout,
1259 const char * const * constraints,
1260 bool *allows_mem, bool *allows_reg)
1262 const char *constraint = *constraint_p;
1263 const char *orig_constraint = constraint;
1264 size_t c_len = strlen (constraint);
1267 /* Assume the constraint doesn't allow the use of either
1268 a register or memory. */
1269 *allows_mem = false;
1270 *allows_reg = false;
1272 /* Make sure constraint has neither `=', `+', nor '&'. */
1274 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1275 switch (constraint[j])
1277 case '+': case '=': case '&':
1278 if (constraint == orig_constraint)
1280 error ("input operand constraint contains `%c'", constraint[j]);
1286 if (constraint == orig_constraint
1287 && input_num + 1 == ninputs - ninout)
1289 error ("`%%' constraint used with last operand");
1294 case 'V': case 'm': case 'o':
1299 case '?': case '!': case '*': case '#':
1300 case 'E': case 'F': case 'G': case 'H':
1301 case 's': case 'i': case 'n':
1302 case 'I': case 'J': case 'K': case 'L': case 'M':
1303 case 'N': case 'O': case 'P': case ',':
1306 /* Whether or not a numeric constraint allows a register is
1307 decided by the matching constraint, and so there is no need
1308 to do anything special with them. We must handle them in
1309 the default case, so that we don't unnecessarily force
1310 operands to memory. */
1311 case '0': case '1': case '2': case '3': case '4':
1312 case '5': case '6': case '7': case '8': case '9':
1315 unsigned long match;
1317 match = strtoul (constraint + j, &end, 10);
1318 if (match >= (unsigned long) noutputs)
1320 error ("matching constraint references invalid operand number");
1324 /* Try and find the real constraint for this dup. Only do this
1325 if the matching constraint is the only alternative. */
1327 && (j == 0 || (j == 1 && constraint[0] == '%')))
1329 constraint = constraints[match];
1330 *constraint_p = constraint;
1331 c_len = strlen (constraint);
1333 /* ??? At the end of the loop, we will skip the first part of
1334 the matched constraint. This assumes not only that the
1335 other constraint is an output constraint, but also that
1336 the '=' or '+' come first. */
1340 j = end - constraint;
1341 /* Anticipate increment at end of loop. */
1356 if (! ISALPHA (constraint[j]))
1358 error ("invalid punctuation `%c' in constraint", constraint[j]);
1361 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1364 #ifdef EXTRA_CONSTRAINT_STR
1365 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1367 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1371 /* Otherwise we can't assume anything about the nature of
1372 the constraint except that it isn't purely registers.
1373 Treat it like "g" and hope for the best. */
1384 /* Check for overlap between registers marked in CLOBBERED_REGS and
1385 anything inappropriate in DECL. Emit error and return TRUE for error,
1389 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
1391 /* Conflicts between asm-declared register variables and the clobber
1392 list are not allowed. */
1393 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1394 && DECL_REGISTER (decl)
1395 && REG_P (DECL_RTL (decl))
1396 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1398 rtx reg = DECL_RTL (decl);
1401 for (regno = REGNO (reg);
1402 regno < (REGNO (reg)
1403 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1405 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1407 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1408 IDENTIFIER_POINTER (DECL_NAME (decl)));
1410 /* Reset registerness to stop multiple errors emitted for a
1412 DECL_REGISTER (decl) = 0;
1419 /* Generate RTL for an asm statement with arguments.
1420 STRING is the instruction template.
1421 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1422 Each output or input has an expression in the TREE_VALUE and
1423 and a tree list in TREE_PURPOSE which in turn contains a constraint
1424 name in TREE_VALUE (or NULL_TREE) and a constraint string
1426 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1427 that is clobbered by this insn.
1429 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1430 Some elements of OUTPUTS may be replaced with trees representing temporary
1431 values. The caller should copy those temporary values to the originally
1434 VOL nonzero means the insn is volatile; don't optimize it. */
1437 expand_asm_operands (tree string, tree outputs, tree inputs,
1438 tree clobbers, int vol, const char *filename, int line)
1440 rtvec argvec, constraintvec;
1442 int ninputs = list_length (inputs);
1443 int noutputs = list_length (outputs);
1446 HARD_REG_SET clobbered_regs;
1447 int clobber_conflict_found = 0;
1451 /* Vector of RTX's of evaluated output operands. */
1452 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
1453 int *inout_opnum = alloca (noutputs * sizeof (int));
1454 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
1455 enum machine_mode *inout_mode
1456 = alloca (noutputs * sizeof (enum machine_mode));
1457 const char **constraints
1458 = alloca ((noutputs + ninputs) * sizeof (const char *));
1459 int old_generating_concat_p = generating_concat_p;
1461 /* An ASM with no outputs needs to be treated as volatile, for now. */
1465 if (! check_operand_nalternatives (outputs, inputs))
1468 if (! check_unique_operand_names (outputs, inputs))
1471 string = resolve_asm_operand_names (string, outputs, inputs);
1473 /* Collect constraints. */
1475 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1476 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1477 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1478 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1480 #ifdef MD_ASM_CLOBBERS
1481 /* Sometimes we wish to automatically clobber registers across an asm.
1482 Case in point is when the i386 backend moved from cc0 to a hard reg --
1483 maintaining source-level compatibility means automatically clobbering
1484 the flags register. */
1485 MD_ASM_CLOBBERS (clobbers);
1488 /* Count the number of meaningful clobbered registers, ignoring what
1489 we would ignore later. */
1491 CLEAR_HARD_REG_SET (clobbered_regs);
1492 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1494 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1496 i = decode_reg_name (regname);
1497 if (i >= 0 || i == -4)
1500 error ("unknown register name `%s' in `asm'", regname);
1502 /* Mark clobbered registers. */
1505 /* Clobbering the PIC register is an error */
1506 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1508 error ("PIC register `%s' clobbered in `asm'", regname);
1512 SET_HARD_REG_BIT (clobbered_regs, i);
1518 /* First pass over inputs and outputs checks validity and sets
1519 mark_addressable if needed. */
1522 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1524 tree val = TREE_VALUE (tail);
1525 tree type = TREE_TYPE (val);
1526 const char *constraint;
1531 /* If there's an erroneous arg, emit no insn. */
1532 if (type == error_mark_node)
1535 /* Try to parse the output constraint. If that fails, there's
1536 no point in going further. */
1537 constraint = constraints[i];
1538 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1539 &allows_mem, &allows_reg, &is_inout))
1546 && GET_CODE (DECL_RTL (val)) == REG
1547 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1548 (*lang_hooks.mark_addressable) (val);
1555 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1557 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1561 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1563 bool allows_reg, allows_mem;
1564 const char *constraint;
1566 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1567 would get VOIDmode and that could cause a crash in reload. */
1568 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1571 constraint = constraints[i + noutputs];
1572 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1573 constraints, &allows_mem, &allows_reg))
1576 if (! allows_reg && allows_mem)
1577 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1580 /* Second pass evaluates arguments. */
1583 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1585 tree val = TREE_VALUE (tail);
1586 tree type = TREE_TYPE (val);
1592 if (!parse_output_constraint (&constraints[i], i, ninputs,
1593 noutputs, &allows_mem, &allows_reg,
1597 /* If an output operand is not a decl or indirect ref and our constraint
1598 allows a register, make a temporary to act as an intermediate.
1599 Make the asm insn write into that, then our caller will copy it to
1600 the real output operand. Likewise for promoted variables. */
1602 generating_concat_p = 0;
1604 real_output_rtx[i] = NULL_RTX;
1605 if ((TREE_CODE (val) == INDIRECT_REF
1608 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1609 && ! (GET_CODE (DECL_RTL (val)) == REG
1610 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1614 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1615 if (GET_CODE (op) == MEM)
1616 op = validize_mem (op);
1618 if (! allows_reg && GET_CODE (op) != MEM)
1619 error ("output number %d not directly addressable", i);
1620 if ((! allows_mem && GET_CODE (op) == MEM)
1621 || GET_CODE (op) == CONCAT)
1623 real_output_rtx[i] = protect_from_queue (op, 1);
1624 op = gen_reg_rtx (GET_MODE (op));
1626 emit_move_insn (op, real_output_rtx[i]);
1631 op = assign_temp (type, 0, 0, 1);
1632 op = validize_mem (op);
1633 TREE_VALUE (tail) = make_tree (type, op);
1637 generating_concat_p = old_generating_concat_p;
1641 inout_mode[ninout] = TYPE_MODE (type);
1642 inout_opnum[ninout++] = i;
1645 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1646 clobber_conflict_found = 1;
1649 /* Make vectors for the expression-rtx, constraint strings,
1650 and named operands. */
1652 argvec = rtvec_alloc (ninputs);
1653 constraintvec = rtvec_alloc (ninputs);
1655 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1656 : GET_MODE (output_rtx[0])),
1657 TREE_STRING_POINTER (string),
1658 empty_string, 0, argvec, constraintvec,
1661 MEM_VOLATILE_P (body) = vol;
1663 /* Eval the inputs and put them into ARGVEC.
1664 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1666 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1668 bool allows_reg, allows_mem;
1669 const char *constraint;
1673 constraint = constraints[i + noutputs];
1674 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1675 constraints, &allows_mem, &allows_reg))
1678 generating_concat_p = 0;
1680 val = TREE_VALUE (tail);
1681 type = TREE_TYPE (val);
1682 op = expand_expr (val, NULL_RTX, VOIDmode,
1683 (allows_mem && !allows_reg
1684 ? EXPAND_MEMORY : EXPAND_NORMAL));
1686 /* Never pass a CONCAT to an ASM. */
1687 if (GET_CODE (op) == CONCAT)
1688 op = force_reg (GET_MODE (op), op);
1689 else if (GET_CODE (op) == MEM)
1690 op = validize_mem (op);
1692 if (asm_operand_ok (op, constraint) <= 0)
1695 op = force_reg (TYPE_MODE (type), op);
1696 else if (!allows_mem)
1697 warning ("asm operand %d probably doesn't match constraints",
1699 else if (GET_CODE (op) == MEM)
1701 /* We won't recognize either volatile memory or memory
1702 with a queued address as available a memory_operand
1703 at this point. Ignore it: clearly this *is* a memory. */
1707 warning ("use of memory input without lvalue in "
1708 "asm operand %d is deprecated", i + noutputs);
1710 if (CONSTANT_P (op))
1712 op = force_const_mem (TYPE_MODE (type), op);
1713 op = validize_mem (op);
1715 else if (GET_CODE (op) == REG
1716 || GET_CODE (op) == SUBREG
1717 || GET_CODE (op) == ADDRESSOF
1718 || GET_CODE (op) == CONCAT)
1720 tree qual_type = build_qualified_type (type,
1722 | TYPE_QUAL_CONST));
1723 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1724 memloc = validize_mem (memloc);
1725 emit_move_insn (memloc, op);
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_strdup (buffer));
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 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. */
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);
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 (tree outputs, tree inputs)
1888 if (outputs || inputs)
1890 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1892 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1895 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1897 error ("too many alternatives in `asm'");
1904 const char *constraint
1905 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1907 if (n_occurrences (',', constraint) != nalternatives)
1909 error ("operand constraints for `asm' differ in number of alternatives");
1913 if (TREE_CHAIN (tmp))
1914 tmp = TREE_CHAIN (tmp);
1916 tmp = next, next = 0;
1923 /* A subroutine of expand_asm_operands. Check that all operand names
1924 are unique. Return true if so. We rely on the fact that these names
1925 are identifiers, and so have been canonicalized by get_identifier,
1926 so all we need are pointer comparisons. */
1929 check_unique_operand_names (tree outputs, tree inputs)
1933 for (i = outputs; i ; i = TREE_CHAIN (i))
1935 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1939 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1940 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1944 for (i = inputs; i ; i = TREE_CHAIN (i))
1946 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1950 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1951 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1953 for (j = outputs; j ; j = TREE_CHAIN (j))
1954 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1961 error ("duplicate asm operand name '%s'",
1962 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1966 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1967 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1968 STRING and in the constraints to those numbers. */
1971 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1978 /* Substitute [<name>] in input constraint strings. There should be no
1979 named operands in output constraints. */
1980 for (t = inputs; t ; t = TREE_CHAIN (t))
1982 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1983 if (strchr (c, '[') != NULL)
1985 p = buffer = xstrdup (c);
1986 while ((p = strchr (p, '[')) != NULL)
1987 p = resolve_operand_name_1 (p, outputs, inputs);
1988 TREE_VALUE (TREE_PURPOSE (t))
1989 = build_string (strlen (buffer), buffer);
1994 /* Now check for any needed substitutions in the template. */
1995 c = TREE_STRING_POINTER (string);
1996 while ((c = strchr (c, '%')) != NULL)
2000 else if (ISALPHA (c[1]) && c[2] == '[')
2011 /* OK, we need to make a copy so we can perform the substitutions.
2012 Assume that we will not need extra space--we get to remove '['
2013 and ']', which means we cannot have a problem until we have more
2014 than 999 operands. */
2015 buffer = xstrdup (TREE_STRING_POINTER (string));
2016 p = buffer + (c - TREE_STRING_POINTER (string));
2018 while ((p = strchr (p, '%')) != NULL)
2022 else if (ISALPHA (p[1]) && p[2] == '[')
2030 p = resolve_operand_name_1 (p, outputs, inputs);
2033 string = build_string (strlen (buffer), buffer);
2040 /* A subroutine of resolve_operand_names. P points to the '[' for a
2041 potential named operand of the form [<name>]. In place, replace
2042 the name and brackets with a number. Return a pointer to the
2043 balance of the string after substitution. */
2046 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
2053 /* Collect the operand name. */
2054 q = strchr (p, ']');
2057 error ("missing close brace for named operand");
2058 return strchr (p, '\0');
2062 /* Resolve the name to a number. */
2063 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2065 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2068 const char *c = TREE_STRING_POINTER (name);
2069 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2073 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2075 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2078 const char *c = TREE_STRING_POINTER (name);
2079 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2085 error ("undefined named operand '%s'", p + 1);
2089 /* Replace the name with the number. Unfortunately, not all libraries
2090 get the return value of sprintf correct, so search for the end of the
2091 generated string by hand. */
2092 sprintf (p, "%d", op);
2093 p = strchr (p, '\0');
2095 /* Verify the no extra buffer space assumption. */
2099 /* Shift the rest of the buffer down to fill the gap. */
2100 memmove (p, q + 1, strlen (q + 1) + 1);
2105 /* Generate RTL to evaluate the expression EXP
2106 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2107 Provided just for backward-compatibility. expand_expr_stmt_value()
2108 should be used for new code. */
2111 expand_expr_stmt (tree exp)
2113 expand_expr_stmt_value (exp, -1, 1);
2116 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2117 whether to (1) save the value of the expression, (0) discard it or
2118 (-1) use expr_stmts_for_value to tell. The use of -1 is
2119 deprecated, and retained only for backward compatibility. */
2122 expand_expr_stmt_value (tree exp, int want_value, int maybe_last)
2127 if (want_value == -1)
2128 want_value = expr_stmts_for_value != 0;
2130 /* If -Wextra, warn about statements with no side effects,
2131 except for an explicit cast to void (e.g. for assert()), and
2132 except for last statement in ({...}) where they may be useful. */
2134 && (expr_stmts_for_value == 0 || ! maybe_last)
2135 && exp != error_mark_node
2136 && warn_unused_value)
2138 if (TREE_SIDE_EFFECTS (exp))
2139 warn_if_unused_value (exp);
2140 else if (!VOID_TYPE_P (TREE_TYPE (exp)))
2141 warning ("%Hstatement with no effect", &emit_locus);
2144 /* If EXP is of function type and we are expanding statements for
2145 value, convert it to pointer-to-function. */
2146 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2147 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2149 /* The call to `expand_expr' could cause last_expr_type and
2150 last_expr_value to get reset. Therefore, we set last_expr_value
2151 and last_expr_type *after* calling expand_expr. */
2152 value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
2154 type = TREE_TYPE (exp);
2156 /* If all we do is reference a volatile value in memory,
2157 copy it to a register to be sure it is actually touched. */
2158 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2160 if (TYPE_MODE (type) == VOIDmode)
2162 else if (TYPE_MODE (type) != BLKmode)
2163 value = copy_to_reg (value);
2166 rtx lab = gen_label_rtx ();
2168 /* Compare the value with itself to reference it. */
2169 emit_cmp_and_jump_insns (value, value, EQ,
2170 expand_expr (TYPE_SIZE (type),
2171 NULL_RTX, VOIDmode, 0),
2177 /* If this expression is part of a ({...}) and is in memory, we may have
2178 to preserve temporaries. */
2179 preserve_temp_slots (value);
2181 /* Free any temporaries used to evaluate this expression. Any temporary
2182 used as a result of this expression will already have been preserved
2188 last_expr_value = value;
2189 last_expr_type = type;
2195 /* Warn if EXP contains any computations whose results are not used.
2196 Return 1 if a warning is printed; 0 otherwise. */
2199 warn_if_unused_value (tree exp)
2201 if (TREE_USED (exp))
2204 /* Don't warn about void constructs. This includes casting to void,
2205 void function calls, and statement expressions with a final cast
2207 if (VOID_TYPE_P (TREE_TYPE (exp)))
2210 switch (TREE_CODE (exp))
2212 case PREINCREMENT_EXPR:
2213 case POSTINCREMENT_EXPR:
2214 case PREDECREMENT_EXPR:
2215 case POSTDECREMENT_EXPR:
2221 case TRY_CATCH_EXPR:
2222 case WITH_CLEANUP_EXPR:
2227 /* For a binding, warn if no side effect within it. */
2228 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2231 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2233 case TRUTH_ORIF_EXPR:
2234 case TRUTH_ANDIF_EXPR:
2235 /* In && or ||, warn if 2nd operand has no side effect. */
2236 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2239 if (TREE_NO_UNUSED_WARNING (exp))
2241 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2243 /* Let people do `(foo (), 0)' without a warning. */
2244 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2246 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2250 case NON_LVALUE_EXPR:
2251 /* Don't warn about conversions not explicit in the user's program. */
2252 if (TREE_NO_UNUSED_WARNING (exp))
2254 /* Assignment to a cast usually results in a cast of a modify.
2255 Don't complain about that. There can be an arbitrary number of
2256 casts before the modify, so we must loop until we find the first
2257 non-cast expression and then test to see if that is a modify. */
2259 tree tem = TREE_OPERAND (exp, 0);
2261 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2262 tem = TREE_OPERAND (tem, 0);
2264 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2265 || TREE_CODE (tem) == CALL_EXPR)
2271 /* Don't warn about automatic dereferencing of references, since
2272 the user cannot control it. */
2273 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2274 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2278 /* Referencing a volatile value is a side effect, so don't warn. */
2280 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2281 && TREE_THIS_VOLATILE (exp))
2284 /* If this is an expression which has no operands, there is no value
2285 to be unused. There are no such language-independent codes,
2286 but front ends may define such. */
2287 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2288 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2292 /* If this is an expression with side effects, don't warn. */
2293 if (TREE_SIDE_EFFECTS (exp))
2296 warning ("%Hvalue computed is not used", &emit_locus);
2301 /* Clear out the memory of the last expression evaluated. */
2304 clear_last_expr (void)
2306 last_expr_type = NULL_TREE;
2307 last_expr_value = NULL_RTX;
2310 /* Begin a statement-expression, i.e., a series of statements which
2311 may return a value. Return the RTL_EXPR for this statement expr.
2312 The caller must save that value and pass it to
2313 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2314 in the statement-expression are deallocated at the end of the
2318 expand_start_stmt_expr (int has_scope)
2322 /* Make the RTL_EXPR node temporary, not momentary,
2323 so that rtl_expr_chain doesn't become garbage. */
2324 t = make_node (RTL_EXPR);
2325 do_pending_stack_adjust ();
2327 start_sequence_for_rtl_expr (t);
2331 expr_stmts_for_value++;
2335 /* Restore the previous state at the end of a statement that returns a value.
2336 Returns a tree node representing the statement's value and the
2337 insns to compute the value.
2339 The nodes of that expression have been freed by now, so we cannot use them.
2340 But we don't want to do that anyway; the expression has already been
2341 evaluated and now we just want to use the value. So generate a RTL_EXPR
2342 with the proper type and RTL value.
2344 If the last substatement was not an expression,
2345 return something with type `void'. */
2348 expand_end_stmt_expr (tree t)
2352 if (! last_expr_value || ! last_expr_type)
2354 last_expr_value = const0_rtx;
2355 last_expr_type = void_type_node;
2357 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2358 /* Remove any possible QUEUED. */
2359 last_expr_value = protect_from_queue (last_expr_value, 0);
2363 TREE_TYPE (t) = last_expr_type;
2364 RTL_EXPR_RTL (t) = last_expr_value;
2365 RTL_EXPR_SEQUENCE (t) = get_insns ();
2367 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2371 /* Don't consider deleting this expr or containing exprs at tree level. */
2372 TREE_SIDE_EFFECTS (t) = 1;
2373 /* Propagate volatility of the actual RTL expr. */
2374 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2377 expr_stmts_for_value--;
2382 /* Generate RTL for the start of an if-then. COND is the expression
2383 whose truth should be tested.
2385 If EXITFLAG is nonzero, this conditional is visible to
2386 `exit_something'. */
2389 expand_start_cond (tree cond, int exitflag)
2391 struct nesting *thiscond = ALLOC_NESTING ();
2393 /* Make an entry on cond_stack for the cond we are entering. */
2395 thiscond->desc = COND_NESTING;
2396 thiscond->next = cond_stack;
2397 thiscond->all = nesting_stack;
2398 thiscond->depth = ++nesting_depth;
2399 thiscond->data.cond.next_label = gen_label_rtx ();
2400 /* Before we encounter an `else', we don't need a separate exit label
2401 unless there are supposed to be exit statements
2402 to exit this conditional. */
2403 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2404 thiscond->data.cond.endif_label = thiscond->exit_label;
2405 cond_stack = thiscond;
2406 nesting_stack = thiscond;
2408 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2411 /* Generate RTL between then-clause and the elseif-clause
2412 of an if-then-elseif-.... */
2415 expand_start_elseif (tree cond)
2417 if (cond_stack->data.cond.endif_label == 0)
2418 cond_stack->data.cond.endif_label = gen_label_rtx ();
2419 emit_jump (cond_stack->data.cond.endif_label);
2420 emit_label (cond_stack->data.cond.next_label);
2421 cond_stack->data.cond.next_label = gen_label_rtx ();
2422 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2425 /* Generate RTL between the then-clause and the else-clause
2426 of an if-then-else. */
2429 expand_start_else (void)
2431 if (cond_stack->data.cond.endif_label == 0)
2432 cond_stack->data.cond.endif_label = gen_label_rtx ();
2434 emit_jump (cond_stack->data.cond.endif_label);
2435 emit_label (cond_stack->data.cond.next_label);
2436 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2439 /* After calling expand_start_else, turn this "else" into an "else if"
2440 by providing another condition. */
2443 expand_elseif (tree cond)
2445 cond_stack->data.cond.next_label = gen_label_rtx ();
2446 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2449 /* Generate RTL for the end of an if-then.
2450 Pop the record for it off of cond_stack. */
2453 expand_end_cond (void)
2455 struct nesting *thiscond = cond_stack;
2457 do_pending_stack_adjust ();
2458 if (thiscond->data.cond.next_label)
2459 emit_label (thiscond->data.cond.next_label);
2460 if (thiscond->data.cond.endif_label)
2461 emit_label (thiscond->data.cond.endif_label);
2463 POPSTACK (cond_stack);
2467 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2468 loop should be exited by `exit_something'. This is a loop for which
2469 `expand_continue' will jump to the top of the loop.
2471 Make an entry on loop_stack to record the labels associated with
2475 expand_start_loop (int exit_flag)
2477 struct nesting *thisloop = ALLOC_NESTING ();
2479 /* Make an entry on loop_stack for the loop we are entering. */
2481 thisloop->desc = LOOP_NESTING;
2482 thisloop->next = loop_stack;
2483 thisloop->all = nesting_stack;
2484 thisloop->depth = ++nesting_depth;
2485 thisloop->data.loop.start_label = gen_label_rtx ();
2486 thisloop->data.loop.end_label = gen_label_rtx ();
2487 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2488 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2489 loop_stack = thisloop;
2490 nesting_stack = thisloop;
2492 do_pending_stack_adjust ();
2494 emit_note (NOTE_INSN_LOOP_BEG);
2495 emit_label (thisloop->data.loop.start_label);
2500 /* Like expand_start_loop but for a loop where the continuation point
2501 (for expand_continue_loop) will be specified explicitly. */
2504 expand_start_loop_continue_elsewhere (int exit_flag)
2506 struct nesting *thisloop = expand_start_loop (exit_flag);
2507 loop_stack->data.loop.continue_label = gen_label_rtx ();
2511 /* Begin a null, aka do { } while (0) "loop". But since the contents
2512 of said loop can still contain a break, we must frob the loop nest. */
2515 expand_start_null_loop (void)
2517 struct nesting *thisloop = ALLOC_NESTING ();
2519 /* Make an entry on loop_stack for the loop we are entering. */
2521 thisloop->desc = LOOP_NESTING;
2522 thisloop->next = loop_stack;
2523 thisloop->all = nesting_stack;
2524 thisloop->depth = ++nesting_depth;
2525 thisloop->data.loop.start_label = emit_note (NOTE_INSN_DELETED);
2526 thisloop->data.loop.end_label = gen_label_rtx ();
2527 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2528 thisloop->exit_label = thisloop->data.loop.end_label;
2529 loop_stack = thisloop;
2530 nesting_stack = thisloop;
2535 /* Specify the continuation point for a loop started with
2536 expand_start_loop_continue_elsewhere.
2537 Use this at the point in the code to which a continue statement
2541 expand_loop_continue_here (void)
2543 do_pending_stack_adjust ();
2544 emit_note (NOTE_INSN_LOOP_CONT);
2545 emit_label (loop_stack->data.loop.continue_label);
2548 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2549 Pop the block off of loop_stack. */
2552 expand_end_loop (void)
2554 rtx start_label = loop_stack->data.loop.start_label;
2556 int eh_regions, debug_blocks;
2559 /* Mark the continue-point at the top of the loop if none elsewhere. */
2560 if (start_label == loop_stack->data.loop.continue_label)
2561 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2563 do_pending_stack_adjust ();
2565 /* If the loop starts with a loop exit, roll that to the end where
2566 it will optimize together with the jump back.
2568 If the loop presently looks like this (in pseudo-C):
2572 if (test) goto end_label;
2578 transform it to look like:
2585 if (test) goto end_label;
2589 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2590 the end of the entry conditional. Without this, our lexical scan
2591 can't tell the difference between an entry conditional and a
2592 body conditional that exits the loop. Mistaking the two means
2593 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2594 screw up loop unrolling.
2596 Things will be oh so much better when loop optimization is done
2597 off of a proper control flow graph... */
2599 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2602 eh_regions = debug_blocks = 0;
2603 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2604 if (GET_CODE (etc_note) == NOTE)
2606 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2609 /* We must not walk into a nested loop. */
2610 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2612 etc_note = NULL_RTX;
2616 /* At the same time, scan for EH region notes, as we don't want
2617 to scrog region nesting. This shouldn't happen, but... */
2618 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2620 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2622 if (--eh_regions < 0)
2623 /* We've come to the end of an EH region, but never saw the
2624 beginning of that region. That means that an EH region
2625 begins before the top of the loop, and ends in the middle
2626 of it. The existence of such a situation violates a basic
2627 assumption in this code, since that would imply that even
2628 when EH_REGIONS is zero, we might move code out of an
2629 exception region. */
2633 /* Likewise for debug scopes. In this case we'll either (1) move
2634 all of the notes if they are properly nested or (2) leave the
2635 notes alone and only rotate the loop at high optimization
2636 levels when we expect to scrog debug info. */
2637 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2639 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2642 else if (INSN_P (etc_note))
2649 && (debug_blocks == 0 || optimize >= 2)
2650 && NEXT_INSN (etc_note) != NULL_RTX
2651 && ! any_condjump_p (get_last_insn ()))
2653 /* We found one. Move everything from START to ETC to the end
2654 of the loop, and add a jump from the top of the loop. */
2655 rtx top_label = gen_label_rtx ();
2656 rtx start_move = start_label;
2658 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2659 then we want to move this note also. */
2660 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2661 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2662 start_move = PREV_INSN (start_move);
2664 emit_label_before (top_label, start_move);
2666 /* Actually move the insns. If the debug scopes are nested, we
2667 can move everything at once. Otherwise we have to move them
2668 one by one and squeeze out the block notes. */
2669 if (debug_blocks == 0)
2670 reorder_insns (start_move, etc_note, get_last_insn ());
2673 rtx insn, next_insn;
2674 for (insn = start_move; insn; insn = next_insn)
2676 /* Figure out which insn comes after this one. We have
2677 to do this before we move INSN. */
2678 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2680 if (GET_CODE (insn) == NOTE
2681 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2682 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2685 reorder_insns (insn, insn, get_last_insn ());
2689 /* Add the jump from the top of the loop. */
2690 emit_jump_insn_before (gen_jump (start_label), top_label);
2691 emit_barrier_before (top_label);
2692 start_label = top_label;
2695 emit_jump (start_label);
2696 emit_note (NOTE_INSN_LOOP_END);
2697 emit_label (loop_stack->data.loop.end_label);
2699 POPSTACK (loop_stack);
2704 /* Finish a null loop, aka do { } while (0). */
2707 expand_end_null_loop (void)
2709 do_pending_stack_adjust ();
2710 emit_label (loop_stack->data.loop.end_label);
2712 POPSTACK (loop_stack);
2717 /* Generate a jump to the current loop's continue-point.
2718 This is usually the top of the loop, but may be specified
2719 explicitly elsewhere. If not currently inside a loop,
2720 return 0 and do nothing; caller will print an error message. */
2723 expand_continue_loop (struct nesting *whichloop)
2725 /* Emit information for branch prediction. */
2728 if (flag_guess_branch_prob)
2730 note = emit_note (NOTE_INSN_PREDICTION);
2731 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2735 whichloop = loop_stack;
2738 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2743 /* Generate a jump to exit the current loop. If not currently inside a loop,
2744 return 0 and do nothing; caller will print an error message. */
2747 expand_exit_loop (struct nesting *whichloop)
2751 whichloop = loop_stack;
2754 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2758 /* Generate a conditional jump to exit the current loop if COND
2759 evaluates to zero. If not currently inside a loop,
2760 return 0 and do nothing; caller will print an error message. */
2763 expand_exit_loop_if_false (struct nesting *whichloop, tree cond)
2769 whichloop = loop_stack;
2773 if (integer_nonzerop (cond))
2775 if (integer_zerop (cond))
2776 return expand_exit_loop (whichloop);
2778 /* Check if we definitely won't need a fixup. */
2779 if (whichloop == nesting_stack)
2781 jumpifnot (cond, whichloop->data.loop.end_label);
2785 /* In order to handle fixups, we actually create a conditional jump
2786 around an unconditional branch to exit the loop. If fixups are
2787 necessary, they go before the unconditional branch. */
2789 label = gen_label_rtx ();
2790 jumpif (cond, label);
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 (struct nesting *whichloop, tree cond)
2805 if (! expand_exit_loop_if_false (whichloop, cond))
2808 emit_note (NOTE_INSN_LOOP_END_TOP_COND);
2812 /* Return nonzero if we should preserve sub-expressions as separate
2813 pseudos. We never do so if we aren't optimizing. We always do so
2814 if -fexpensive-optimizations.
2816 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2817 the loop may still be a small one. */
2820 preserve_subexpressions_p (void)
2824 if (flag_expensive_optimizations)
2827 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2830 insn = get_last_insn_anywhere ();
2833 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2834 < n_non_fixed_regs * 3));
2838 /* Generate a jump to exit the current loop, conditional, binding contour
2839 or case statement. Not all such constructs are visible to this function,
2840 only those started with EXIT_FLAG nonzero. Individual languages use
2841 the EXIT_FLAG parameter to control which kinds of constructs you can
2844 If not currently inside anything that can be exited,
2845 return 0 and do nothing; caller will print an error message. */
2848 expand_exit_something (void)
2852 for (n = nesting_stack; n; n = n->all)
2853 if (n->exit_label != 0)
2855 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2862 /* Generate RTL to return from the current function, with no value.
2863 (That is, we do not do anything about returning any value.) */
2866 expand_null_return (void)
2870 last_insn = get_last_insn ();
2872 /* If this function was declared to return a value, but we
2873 didn't, clobber the return registers so that they are not
2874 propagated live to the rest of the function. */
2875 clobber_return_register ();
2877 expand_null_return_1 (last_insn);
2880 /* Try to guess whether the value of return means error code. */
2881 static enum br_predictor
2882 return_prediction (rtx val)
2884 /* Different heuristics for pointers and scalars. */
2885 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2887 /* NULL is usually not returned. */
2888 if (val == const0_rtx)
2889 return PRED_NULL_RETURN;
2893 /* Negative return values are often used to indicate
2895 if (GET_CODE (val) == CONST_INT
2896 && INTVAL (val) < 0)
2897 return PRED_NEGATIVE_RETURN;
2898 /* Constant return values are also usually erors,
2899 zero/one often mean booleans so exclude them from the
2901 if (CONSTANT_P (val)
2902 && (val != const0_rtx && val != const1_rtx))
2903 return PRED_CONST_RETURN;
2905 return PRED_NO_PREDICTION;
2908 /* Generate RTL to return from the current function, with value VAL. */
2911 expand_value_return (rtx val)
2915 enum br_predictor pred;
2917 if (flag_guess_branch_prob
2918 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2920 /* Emit information for branch prediction. */
2923 note = emit_note (NOTE_INSN_PREDICTION);
2925 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2929 last_insn = get_last_insn ();
2930 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2932 /* Copy the value to the return location
2933 unless it's already there. */
2935 if (return_reg != val)
2937 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2938 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
2940 int unsignedp = TREE_UNSIGNED (type);
2941 enum machine_mode old_mode
2942 = DECL_MODE (DECL_RESULT (current_function_decl));
2943 enum machine_mode mode
2944 = promote_mode (type, old_mode, &unsignedp, 1);
2946 if (mode != old_mode)
2947 val = convert_modes (mode, old_mode, val, unsignedp);
2949 if (GET_CODE (return_reg) == PARALLEL)
2950 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
2952 emit_move_insn (return_reg, val);
2955 expand_null_return_1 (last_insn);
2958 /* Output a return with no value. If LAST_INSN is nonzero,
2959 pretend that the return takes place after LAST_INSN. */
2962 expand_null_return_1 (rtx last_insn)
2964 rtx end_label = cleanup_label ? cleanup_label : return_label;
2966 clear_pending_stack_adjust ();
2967 do_pending_stack_adjust ();
2971 end_label = return_label = gen_label_rtx ();
2972 expand_goto_internal (NULL_TREE, end_label, last_insn);
2975 /* Generate RTL to evaluate the expression RETVAL and return it
2976 from the current function. */
2979 expand_return (tree retval)
2981 /* If there are any cleanups to be performed, then they will
2982 be inserted following LAST_INSN. It is desirable
2983 that the last_insn, for such purposes, should be the
2984 last insn before computing the return value. Otherwise, cleanups
2985 which call functions can clobber the return value. */
2986 /* ??? rms: I think that is erroneous, because in C++ it would
2987 run destructors on variables that might be used in the subsequent
2988 computation of the return value. */
2994 /* If function wants no value, give it none. */
2995 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2997 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2999 expand_null_return ();
3003 if (retval == error_mark_node)
3005 /* Treat this like a return of no value from a function that
3007 expand_null_return ();
3010 else if (TREE_CODE (retval) == RESULT_DECL)
3011 retval_rhs = retval;
3012 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3013 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3014 retval_rhs = TREE_OPERAND (retval, 1);
3015 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3016 /* Recognize tail-recursive call to void function. */
3017 retval_rhs = retval;
3019 retval_rhs = NULL_TREE;
3021 last_insn = get_last_insn ();
3023 /* Distribute return down conditional expr if either of the sides
3024 may involve tail recursion (see test below). This enhances the number
3025 of tail recursions we see. Don't do this always since it can produce
3026 sub-optimal code in some cases and we distribute assignments into
3027 conditional expressions when it would help. */
3029 if (optimize && retval_rhs != 0
3030 && frame_offset == 0
3031 && TREE_CODE (retval_rhs) == COND_EXPR
3032 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3033 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3035 rtx label = gen_label_rtx ();
3038 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3039 start_cleanup_deferral ();
3040 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3041 DECL_RESULT (current_function_decl),
3042 TREE_OPERAND (retval_rhs, 1));
3043 TREE_SIDE_EFFECTS (expr) = 1;
3044 expand_return (expr);
3047 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3048 DECL_RESULT (current_function_decl),
3049 TREE_OPERAND (retval_rhs, 2));
3050 TREE_SIDE_EFFECTS (expr) = 1;
3051 expand_return (expr);
3052 end_cleanup_deferral ();
3056 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3058 /* If the result is an aggregate that is being returned in one (or more)
3059 registers, load the registers here. The compiler currently can't handle
3060 copying a BLKmode value into registers. We could put this code in a
3061 more general area (for use by everyone instead of just function
3062 call/return), but until this feature is generally usable it is kept here
3063 (and in expand_call). The value must go into a pseudo in case there
3064 are cleanups that will clobber the real return register. */
3067 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3068 && GET_CODE (result_rtl) == REG)
3071 unsigned HOST_WIDE_INT bitpos, xbitpos;
3072 unsigned HOST_WIDE_INT big_endian_correction = 0;
3073 unsigned HOST_WIDE_INT bytes
3074 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3075 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3076 unsigned int bitsize
3077 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3078 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
3079 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3080 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3081 enum machine_mode tmpmode, result_reg_mode;
3085 expand_null_return ();
3089 /* Structures whose size is not a multiple of a word are aligned
3090 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
3091 machine, this means we must skip the empty high order bytes when
3092 calculating the bit offset. */
3093 if (BYTES_BIG_ENDIAN
3094 && bytes % UNITS_PER_WORD)
3095 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3098 /* Copy the structure BITSIZE bits at a time. */
3099 for (bitpos = 0, xbitpos = big_endian_correction;
3100 bitpos < bytes * BITS_PER_UNIT;
3101 bitpos += bitsize, xbitpos += bitsize)
3103 /* We need a new destination pseudo each time xbitpos is
3104 on a word boundary and when xbitpos == big_endian_correction
3105 (the first time through). */
3106 if (xbitpos % BITS_PER_WORD == 0
3107 || xbitpos == big_endian_correction)
3109 /* Generate an appropriate register. */
3110 dst = gen_reg_rtx (word_mode);
3111 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3113 /* Clear the destination before we move anything into it. */
3114 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3117 /* We need a new source operand each time bitpos is on a word
3119 if (bitpos % BITS_PER_WORD == 0)
3120 src = operand_subword_force (result_val,
3121 bitpos / BITS_PER_WORD,
3124 /* Use bitpos for the source extraction (left justified) and
3125 xbitpos for the destination store (right justified). */
3126 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3127 extract_bit_field (src, bitsize,
3128 bitpos % BITS_PER_WORD, 1,
3129 NULL_RTX, word_mode, word_mode,
3134 /* Find the smallest integer mode large enough to hold the
3135 entire structure and use that mode instead of BLKmode
3136 on the USE insn for the return register. */
3137 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3138 tmpmode != VOIDmode;
3139 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3140 /* Have we found a large enough mode? */
3141 if (GET_MODE_SIZE (tmpmode) >= bytes)
3144 /* No suitable mode found. */
3145 if (tmpmode == VOIDmode)
3148 PUT_MODE (result_rtl, tmpmode);
3150 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3151 result_reg_mode = word_mode;
3153 result_reg_mode = tmpmode;
3154 result_reg = gen_reg_rtx (result_reg_mode);
3157 for (i = 0; i < n_regs; i++)
3158 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3161 if (tmpmode != result_reg_mode)
3162 result_reg = gen_lowpart (tmpmode, result_reg);
3164 expand_value_return (result_reg);
3166 else if (retval_rhs != 0
3167 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3168 && (GET_CODE (result_rtl) == REG
3169 || (GET_CODE (result_rtl) == PARALLEL)))
3171 /* Calculate the return value into a temporary (usually a pseudo
3173 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3174 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3176 val = assign_temp (nt, 0, 0, 1);
3177 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3178 val = force_not_mem (val);
3180 /* Return the calculated value, doing cleanups first. */
3181 expand_value_return (val);
3185 /* No cleanups or no hard reg used;
3186 calculate value into hard return reg. */
3187 expand_expr (retval, const0_rtx, VOIDmode, 0);
3189 expand_value_return (result_rtl);
3193 /* Attempt to optimize a potential tail recursion call into a goto.
3194 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3195 where to place the jump to the tail recursion label.
3197 Return TRUE if the call was optimized into a goto. */
3200 optimize_tail_recursion (tree arguments, rtx last_insn)
3202 /* Finish checking validity, and if valid emit code to set the
3203 argument variables for the new call. */
3204 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3206 if (tail_recursion_label == 0)
3208 tail_recursion_label = gen_label_rtx ();
3209 emit_label_after (tail_recursion_label,
3210 tail_recursion_reentry);
3213 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3220 /* Emit code to alter this function's formal parms for a tail-recursive call.
3221 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3222 FORMALS is the chain of decls of formals.
3223 Return 1 if this can be done;
3224 otherwise return 0 and do not emit any code. */
3227 tail_recursion_args (tree actuals, tree formals)
3229 tree a = actuals, f = formals;
3233 /* Check that number and types of actuals are compatible
3234 with the formals. This is not always true in valid C code.
3235 Also check that no formal needs to be addressable
3236 and that all formals are scalars. */
3238 /* Also count the args. */
3240 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3242 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3243 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3245 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3248 if (a != 0 || f != 0)
3251 /* Compute all the actuals. */
3253 argvec = alloca (i * sizeof (rtx));
3255 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3256 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3258 /* Find which actual values refer to current values of previous formals.
3259 Copy each of them now, before any formal is changed. */
3261 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3265 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3266 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3272 argvec[i] = copy_to_reg (argvec[i]);
3275 /* Store the values of the actuals into the formals. */
3277 for (f = formals, a = actuals, i = 0; f;
3278 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3280 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3281 emit_move_insn (DECL_RTL (f), argvec[i]);
3284 rtx tmp = argvec[i];
3285 int unsignedp = TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a)));
3286 promote_mode(TREE_TYPE (TREE_VALUE (a)), GET_MODE (tmp),
3288 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3290 tmp = gen_reg_rtx (DECL_MODE (f));
3291 convert_move (tmp, argvec[i], unsignedp);
3293 convert_move (DECL_RTL (f), tmp, unsignedp);
3301 /* Generate the RTL code for entering a binding contour.
3302 The variables are declared one by one, by calls to `expand_decl'.
3304 FLAGS is a bitwise or of the following flags:
3306 1 - Nonzero if this construct should be visible to
3309 2 - Nonzero if this contour does not require a
3310 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3311 language-independent code should set this flag because they
3312 will not create corresponding BLOCK nodes. (There should be
3313 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3314 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3315 when expand_end_bindings is called.
3317 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3318 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3322 expand_start_bindings_and_block (int flags, tree block)
3324 struct nesting *thisblock = ALLOC_NESTING ();
3326 int exit_flag = ((flags & 1) != 0);
3327 int block_flag = ((flags & 2) == 0);
3329 /* If a BLOCK is supplied, then the caller should be requesting a
3330 NOTE_INSN_BLOCK_BEG note. */
3331 if (!block_flag && block)
3334 /* Create a note to mark the beginning of the block. */
3337 note = emit_note (NOTE_INSN_BLOCK_BEG);
3338 NOTE_BLOCK (note) = block;
3341 note = emit_note (NOTE_INSN_DELETED);
3343 /* Make an entry on block_stack for the block we are entering. */
3345 thisblock->desc = BLOCK_NESTING;
3346 thisblock->next = block_stack;
3347 thisblock->all = nesting_stack;
3348 thisblock->depth = ++nesting_depth;
3349 thisblock->data.block.stack_level = 0;
3350 thisblock->data.block.cleanups = 0;
3351 thisblock->data.block.exception_region = 0;
3352 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3354 thisblock->data.block.conditional_code = 0;
3355 thisblock->data.block.last_unconditional_cleanup = note;
3356 /* When we insert instructions after the last unconditional cleanup,
3357 we don't adjust last_insn. That means that a later add_insn will
3358 clobber the instructions we've just added. The easiest way to
3359 fix this is to just insert another instruction here, so that the
3360 instructions inserted after the last unconditional cleanup are
3361 never the last instruction. */
3362 emit_note (NOTE_INSN_DELETED);
3365 && !(block_stack->data.block.cleanups == NULL_TREE
3366 && block_stack->data.block.outer_cleanups == NULL_TREE))
3367 thisblock->data.block.outer_cleanups
3368 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3369 block_stack->data.block.outer_cleanups);
3371 thisblock->data.block.outer_cleanups = 0;
3372 thisblock->data.block.label_chain = 0;
3373 thisblock->data.block.innermost_stack_block = stack_block_stack;
3374 thisblock->data.block.first_insn = note;
3375 thisblock->data.block.block_start_count = ++current_block_start_count;
3376 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3377 block_stack = thisblock;
3378 nesting_stack = thisblock;
3380 /* Make a new level for allocating stack slots. */
3384 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3385 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3386 expand_expr are made. After we end the region, we know that all
3387 space for all temporaries that were created by TARGET_EXPRs will be
3388 destroyed and their space freed for reuse. */
3391 expand_start_target_temps (void)
3393 /* This is so that even if the result is preserved, the space
3394 allocated will be freed, as we know that it is no longer in use. */
3397 /* Start a new binding layer that will keep track of all cleanup
3398 actions to be performed. */
3399 expand_start_bindings (2);
3401 target_temp_slot_level = temp_slot_level;
3405 expand_end_target_temps (void)
3407 expand_end_bindings (NULL_TREE, 0, 0);
3409 /* This is so that even if the result is preserved, the space
3410 allocated will be freed, as we know that it is no longer in use. */
3414 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3415 in question represents the outermost pair of curly braces (i.e. the "body
3416 block") of a function or method.
3418 For any BLOCK node representing a "body block" of a function or method, the
3419 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3420 represents the outermost (function) scope for the function or method (i.e.
3421 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3422 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3425 is_body_block (tree stmt)
3427 if (lang_hooks.no_body_blocks)
3430 if (TREE_CODE (stmt) == BLOCK)
3432 tree parent = BLOCK_SUPERCONTEXT (stmt);
3434 if (parent && TREE_CODE (parent) == BLOCK)
3436 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3438 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3446 /* True if we are currently emitting insns in an area of output code
3447 that is controlled by a conditional expression. This is used by
3448 the cleanup handling code to generate conditional cleanup actions. */
3451 conditional_context (void)
3453 return block_stack && block_stack->data.block.conditional_code;
3456 /* Return an opaque pointer to the current nesting level, so frontend code
3457 can check its own sanity. */
3460 current_nesting_level (void)
3462 return cfun ? block_stack : 0;
3465 /* Emit a handler label for a nonlocal goto handler.
3466 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3469 expand_nl_handler_label (rtx slot, rtx before_insn)
3472 rtx handler_label = gen_label_rtx ();
3474 /* Don't let cleanup_cfg delete the handler. */
3475 LABEL_PRESERVE_P (handler_label) = 1;
3478 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3479 insns = get_insns ();
3481 emit_insn_before (insns, before_insn);
3483 emit_label (handler_label);
3485 return handler_label;
3488 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3491 expand_nl_goto_receiver (void)
3493 #ifdef HAVE_nonlocal_goto
3494 if (! HAVE_nonlocal_goto)
3496 /* First adjust our frame pointer to its actual value. It was
3497 previously set to the start of the virtual area corresponding to
3498 the stacked variables when we branched here and now needs to be
3499 adjusted to the actual hardware fp value.
3501 Assignments are to virtual registers are converted by
3502 instantiate_virtual_regs into the corresponding assignment
3503 to the underlying register (fp in this case) that makes
3504 the original assignment true.
3505 So the following insn will actually be
3506 decrementing fp by STARTING_FRAME_OFFSET. */
3507 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3509 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3510 if (fixed_regs[ARG_POINTER_REGNUM])
3512 #ifdef ELIMINABLE_REGS
3513 /* If the argument pointer can be eliminated in favor of the
3514 frame pointer, we don't need to restore it. We assume here
3515 that if such an elimination is present, it can always be used.
3516 This is the case on all known machines; if we don't make this
3517 assumption, we do unnecessary saving on many machines. */
3518 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3521 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3522 if (elim_regs[i].from == ARG_POINTER_REGNUM
3523 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3526 if (i == ARRAY_SIZE (elim_regs))
3529 /* Now restore our arg pointer from the address at which it
3530 was saved in our stack frame. */
3531 emit_move_insn (virtual_incoming_args_rtx,
3532 copy_to_reg (get_arg_pointer_save_area (cfun)));
3537 #ifdef HAVE_nonlocal_goto_receiver
3538 if (HAVE_nonlocal_goto_receiver)
3539 emit_insn (gen_nonlocal_goto_receiver ());
3543 /* Make handlers for nonlocal gotos taking place in the function calls in
3547 expand_nl_goto_receivers (struct nesting *thisblock)
3550 rtx afterward = gen_label_rtx ();
3555 /* Record the handler address in the stack slot for that purpose,
3556 during this block, saving and restoring the outer value. */
3557 if (thisblock->next != 0)
3558 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3560 rtx save_receiver = gen_reg_rtx (Pmode);
3561 emit_move_insn (XEXP (slot, 0), save_receiver);
3564 emit_move_insn (save_receiver, XEXP (slot, 0));
3565 insns = get_insns ();
3567 emit_insn_before (insns, thisblock->data.block.first_insn);
3570 /* Jump around the handlers; they run only when specially invoked. */
3571 emit_jump (afterward);
3573 /* Make a separate handler for each label. */
3574 link = nonlocal_labels;
3575 slot = nonlocal_goto_handler_slots;
3576 label_list = NULL_RTX;
3577 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3578 /* Skip any labels we shouldn't be able to jump to from here,
3579 we generate one special handler for all of them below which just calls
3581 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3584 lab = expand_nl_handler_label (XEXP (slot, 0),
3585 thisblock->data.block.first_insn);
3586 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3588 expand_nl_goto_receiver ();
3590 /* Jump to the "real" nonlocal label. */
3591 expand_goto (TREE_VALUE (link));
3594 /* A second pass over all nonlocal labels; this time we handle those
3595 we should not be able to jump to at this point. */
3596 link = nonlocal_labels;
3597 slot = nonlocal_goto_handler_slots;
3599 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3600 if (DECL_TOO_LATE (TREE_VALUE (link)))
3603 lab = expand_nl_handler_label (XEXP (slot, 0),
3604 thisblock->data.block.first_insn);
3605 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3611 expand_nl_goto_receiver ();
3612 expand_builtin_trap ();
3615 nonlocal_goto_handler_labels = label_list;
3616 emit_label (afterward);
3619 /* Warn about any unused VARS (which may contain nodes other than
3620 VAR_DECLs, but such nodes are ignored). The nodes are connected
3621 via the TREE_CHAIN field. */
3624 warn_about_unused_variables (tree vars)
3628 if (warn_unused_variable)
3629 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3630 if (TREE_CODE (decl) == VAR_DECL
3631 && ! TREE_USED (decl)
3632 && ! DECL_IN_SYSTEM_HEADER (decl)
3633 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3634 warning ("%Junused variable '%D'", decl, decl);
3637 /* Generate RTL code to terminate a binding contour.
3639 VARS is the chain of VAR_DECL nodes for the variables bound in this
3640 contour. There may actually be other nodes in this chain, but any
3641 nodes other than VAR_DECLS are ignored.
3643 MARK_ENDS is nonzero if we should put a note at the beginning
3644 and end of this binding contour.
3646 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3647 zero if we can jump into this contour only if it does not have a saved
3648 stack level, and negative if we are not to check for invalid use of
3649 labels (because the front end does that). */
3652 expand_end_bindings (tree vars, int mark_ends, int dont_jump_in)
3654 struct nesting *thisblock = block_stack;
3656 /* If any of the variables in this scope were not used, warn the
3658 warn_about_unused_variables (vars);
3660 if (thisblock->exit_label)
3662 do_pending_stack_adjust ();
3663 emit_label (thisblock->exit_label);
3666 /* If necessary, make handlers for nonlocal gotos taking
3667 place in the function calls in this block. */
3668 if (function_call_count != 0 && nonlocal_labels
3669 /* Make handler for outermost block
3670 if there were any nonlocal gotos to this function. */
3671 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3672 /* Make handler for inner block if it has something
3673 special to do when you jump out of it. */
3674 : (thisblock->data.block.cleanups != 0
3675 || thisblock->data.block.stack_level != 0)))
3676 expand_nl_goto_receivers (thisblock);
3678 /* Don't allow jumping into a block that has a stack level.
3679 Cleanups are allowed, though. */
3680 if (dont_jump_in > 0
3681 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3683 struct label_chain *chain;
3685 /* Any labels in this block are no longer valid to go to.
3686 Mark them to cause an error message. */
3687 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3689 DECL_TOO_LATE (chain->label) = 1;
3690 /* If any goto without a fixup came to this label,
3691 that must be an error, because gotos without fixups
3692 come from outside all saved stack-levels. */
3693 if (TREE_ADDRESSABLE (chain->label))
3694 error ("%Jlabel '%D' used before containing binding contour",
3695 chain->label, chain->label);
3699 /* Restore stack level in effect before the block
3700 (only if variable-size objects allocated). */
3701 /* Perform any cleanups associated with the block. */
3703 if (thisblock->data.block.stack_level != 0
3704 || thisblock->data.block.cleanups != 0)
3709 /* Don't let cleanups affect ({...}) constructs. */
3710 int old_expr_stmts_for_value = expr_stmts_for_value;
3711 rtx old_last_expr_value = last_expr_value;
3712 tree old_last_expr_type = last_expr_type;
3713 expr_stmts_for_value = 0;
3715 /* Only clean up here if this point can actually be reached. */
3716 insn = get_last_insn ();
3717 if (GET_CODE (insn) == NOTE)
3718 insn = prev_nonnote_insn (insn);
3719 reachable = (! insn || GET_CODE (insn) != BARRIER);
3721 /* Do the cleanups. */
3722 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3724 do_pending_stack_adjust ();
3726 expr_stmts_for_value = old_expr_stmts_for_value;
3727 last_expr_value = old_last_expr_value;
3728 last_expr_type = old_last_expr_type;
3730 /* Restore the stack level. */
3732 if (reachable && thisblock->data.block.stack_level != 0)
3734 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3735 thisblock->data.block.stack_level, NULL_RTX);
3736 if (nonlocal_goto_handler_slots != 0)
3737 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3741 /* Any gotos out of this block must also do these things.
3742 Also report any gotos with fixups that came to labels in this
3744 fixup_gotos (thisblock,
3745 thisblock->data.block.stack_level,
3746 thisblock->data.block.cleanups,
3747 thisblock->data.block.first_insn,
3751 /* Mark the beginning and end of the scope if requested.
3752 We do this now, after running cleanups on the variables
3753 just going out of scope, so they are in scope for their cleanups. */
3757 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3758 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3761 /* Get rid of the beginning-mark if we don't make an end-mark. */
3762 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3764 /* Restore the temporary level of TARGET_EXPRs. */
3765 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3767 /* Restore block_stack level for containing block. */
3769 stack_block_stack = thisblock->data.block.innermost_stack_block;
3770 POPSTACK (block_stack);
3772 /* Pop the stack slot nesting and free any slots at this level. */
3776 /* Generate code to save the stack pointer at the start of the current block
3777 and set up to restore it on exit. */
3780 save_stack_pointer (void)
3782 struct nesting *thisblock = block_stack;
3784 if (thisblock->data.block.stack_level == 0)
3786 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3787 &thisblock->data.block.stack_level,
3788 thisblock->data.block.first_insn);
3789 stack_block_stack = thisblock;
3793 /* Generate RTL for the automatic variable declaration DECL.
3794 (Other kinds of declarations are simply ignored if seen here.) */
3797 expand_decl (tree decl)
3801 type = TREE_TYPE (decl);
3803 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3804 type in case this node is used in a reference. */
3805 if (TREE_CODE (decl) == CONST_DECL)
3807 DECL_MODE (decl) = TYPE_MODE (type);
3808 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3809 DECL_SIZE (decl) = TYPE_SIZE (type);
3810 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3814 /* Otherwise, only automatic variables need any expansion done. Static and
3815 external variables, and external functions, will be handled by
3816 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3817 nothing. PARM_DECLs are handled in `assign_parms'. */
3818 if (TREE_CODE (decl) != VAR_DECL)
3821 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3824 /* Create the RTL representation for the variable. */
3826 if (type == error_mark_node)
3827 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3829 else if (DECL_SIZE (decl) == 0)
3830 /* Variable with incomplete type. */
3833 if (DECL_INITIAL (decl) == 0)
3834 /* Error message was already done; now avoid a crash. */
3835 x = gen_rtx_MEM (BLKmode, const0_rtx);
3837 /* An initializer is going to decide the size of this array.
3838 Until we know the size, represent its address with a reg. */
3839 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3841 set_mem_attributes (x, decl, 1);
3842 SET_DECL_RTL (decl, x);
3844 else if (DECL_MODE (decl) != BLKmode
3845 /* If -ffloat-store, don't put explicit float vars
3847 && !(flag_float_store
3848 && TREE_CODE (type) == REAL_TYPE)
3849 && ! TREE_THIS_VOLATILE (decl)
3850 && ! DECL_NONLOCAL (decl)
3851 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3853 /* Automatic variable that can go in a register. */
3854 int unsignedp = TREE_UNSIGNED (type);
3855 enum machine_mode reg_mode
3856 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3858 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3860 if (!DECL_ARTIFICIAL (decl))
3861 mark_user_reg (DECL_RTL (decl));
3863 if (POINTER_TYPE_P (type))
3864 mark_reg_pointer (DECL_RTL (decl),
3865 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3867 maybe_set_unchanging (DECL_RTL (decl), decl);
3869 /* If something wants our address, try to use ADDRESSOF. */
3870 if (TREE_ADDRESSABLE (decl))
3871 put_var_into_stack (decl, /*rescan=*/false);
3874 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3875 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3876 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3877 STACK_CHECK_MAX_VAR_SIZE)))
3879 /* Variable of fixed size that goes on the stack. */
3884 /* If we previously made RTL for this decl, it must be an array
3885 whose size was determined by the initializer.
3886 The old address was a register; set that register now
3887 to the proper address. */
3888 if (DECL_RTL_SET_P (decl))
3890 if (GET_CODE (DECL_RTL (decl)) != MEM
3891 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3893 oldaddr = XEXP (DECL_RTL (decl), 0);
3896 /* Set alignment we actually gave this decl. */
3897 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3898 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3899 DECL_USER_ALIGN (decl) = 0;
3901 x = assign_temp (decl, 1, 1, 1);
3902 set_mem_attributes (x, decl, 1);
3903 SET_DECL_RTL (decl, x);
3907 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3908 if (addr != oldaddr)
3909 emit_move_insn (oldaddr, addr);
3913 /* Dynamic-size object: must push space on the stack. */
3915 rtx address, size, x;
3917 /* Record the stack pointer on entry to block, if have
3918 not already done so. */
3919 do_pending_stack_adjust ();
3920 save_stack_pointer ();
3922 /* In function-at-a-time mode, variable_size doesn't expand this,
3924 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3925 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3926 const0_rtx, VOIDmode, 0);
3928 /* Compute the variable's size, in bytes. */
3929 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
3932 /* Allocate space on the stack for the variable. Note that
3933 DECL_ALIGN says how the variable is to be aligned and we
3934 cannot use it to conclude anything about the alignment of
3936 address = allocate_dynamic_stack_space (size, NULL_RTX,
3937 TYPE_ALIGN (TREE_TYPE (decl)));
3939 /* Reference the variable indirect through that rtx. */
3940 x = gen_rtx_MEM (DECL_MODE (decl), address);
3941 set_mem_attributes (x, decl, 1);
3942 SET_DECL_RTL (decl, x);
3945 /* Indicate the alignment we actually gave this variable. */
3946 #ifdef STACK_BOUNDARY
3947 DECL_ALIGN (decl) = STACK_BOUNDARY;
3949 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3951 DECL_USER_ALIGN (decl) = 0;
3955 /* Emit code to perform the initialization of a declaration DECL. */
3958 expand_decl_init (tree decl)
3960 int was_used = TREE_USED (decl);
3962 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
3963 for static decls. */
3964 if (TREE_CODE (decl) == CONST_DECL
3965 || TREE_STATIC (decl))
3968 /* Compute and store the initial value now. */
3972 if (DECL_INITIAL (decl) == error_mark_node)
3974 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3976 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3977 || code == POINTER_TYPE || code == REFERENCE_TYPE)
3978 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3982 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3984 emit_line_note (DECL_SOURCE_LOCATION (decl));
3985 expand_assignment (decl, DECL_INITIAL (decl), 0);
3989 /* Don't let the initialization count as "using" the variable. */
3990 TREE_USED (decl) = was_used;
3992 /* Free any temporaries we made while initializing the decl. */
3993 preserve_temp_slots (NULL_RTX);
3998 /* CLEANUP is an expression to be executed at exit from this binding contour;
3999 for example, in C++, it might call the destructor for this variable.
4001 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4002 CLEANUP multiple times, and have the correct semantics. This
4003 happens in exception handling, for gotos, returns, breaks that
4004 leave the current scope.
4006 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4007 that is not associated with any particular variable. */
4010 expand_decl_cleanup (tree decl, tree cleanup)
4012 struct nesting *thisblock;
4014 /* Error if we are not in any block. */
4015 if (cfun == 0 || block_stack == 0)
4018 thisblock = block_stack;
4020 /* Record the cleanup if there is one. */
4026 tree *cleanups = &thisblock->data.block.cleanups;
4027 int cond_context = conditional_context ();
4031 rtx flag = gen_reg_rtx (word_mode);
4036 emit_move_insn (flag, const0_rtx);
4037 set_flag_0 = get_insns ();
4040 thisblock->data.block.last_unconditional_cleanup
4041 = emit_insn_after (set_flag_0,
4042 thisblock->data.block.last_unconditional_cleanup);
4044 emit_move_insn (flag, const1_rtx);
4046 cond = build_decl (VAR_DECL, NULL_TREE,
4047 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4048 SET_DECL_RTL (cond, flag);
4050 /* Conditionalize the cleanup. */
4051 cleanup = build (COND_EXPR, void_type_node,
4052 (*lang_hooks.truthvalue_conversion) (cond),
4053 cleanup, integer_zero_node);
4054 cleanup = fold (cleanup);
4056 cleanups = &thisblock->data.block.cleanups;
4059 cleanup = unsave_expr (cleanup);
4061 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4064 /* If this block has a cleanup, it belongs in stack_block_stack. */
4065 stack_block_stack = thisblock;
4072 if (! using_eh_for_cleanups_p)
4073 TREE_ADDRESSABLE (t) = 1;
4075 expand_eh_region_start ();
4082 thisblock->data.block.last_unconditional_cleanup
4083 = emit_insn_after (seq,
4084 thisblock->data.block.last_unconditional_cleanup);
4088 thisblock->data.block.last_unconditional_cleanup
4090 /* When we insert instructions after the last unconditional cleanup,
4091 we don't adjust last_insn. That means that a later add_insn will
4092 clobber the instructions we've just added. The easiest way to
4093 fix this is to just insert another instruction here, so that the
4094 instructions inserted after the last unconditional cleanup are
4095 never the last instruction. */
4096 emit_note (NOTE_INSN_DELETED);
4102 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4106 expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only)
4108 int ret = expand_decl_cleanup (decl, cleanup);
4111 tree node = block_stack->data.block.cleanups;
4112 CLEANUP_EH_ONLY (node) = eh_only;
4117 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4118 DECL_ELTS is the list of elements that belong to DECL's type.
4119 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4122 expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts)
4124 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4128 /* If any of the elements are addressable, so is the entire union. */
4129 for (t = decl_elts; t; t = TREE_CHAIN (t))
4130 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4132 TREE_ADDRESSABLE (decl) = 1;
4137 expand_decl_cleanup (decl, cleanup);
4138 x = DECL_RTL (decl);
4140 /* Go through the elements, assigning RTL to each. */
4141 for (t = decl_elts; t; t = TREE_CHAIN (t))
4143 tree decl_elt = TREE_VALUE (t);
4144 tree cleanup_elt = TREE_PURPOSE (t);
4145 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4147 /* If any of the elements are addressable, so is the entire
4149 if (TREE_USED (decl_elt))
4150 TREE_USED (decl) = 1;
4152 /* Propagate the union's alignment to the elements. */
4153 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4154 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4156 /* If the element has BLKmode and the union doesn't, the union is
4157 aligned such that the element doesn't need to have BLKmode, so
4158 change the element's mode to the appropriate one for its size. */
4159 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4160 DECL_MODE (decl_elt) = mode
4161 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4163 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4164 instead create a new MEM rtx with the proper mode. */
4165 if (GET_CODE (x) == MEM)
4167 if (mode == GET_MODE (x))
4168 SET_DECL_RTL (decl_elt, x);
4170 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4172 else if (GET_CODE (x) == REG)
4174 if (mode == GET_MODE (x))
4175 SET_DECL_RTL (decl_elt, x);
4177 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4182 /* Record the cleanup if there is one. */
4185 thisblock->data.block.cleanups
4186 = tree_cons (decl_elt, cleanup_elt,
4187 thisblock->data.block.cleanups);
4191 /* Expand a list of cleanups LIST.
4192 Elements may be expressions or may be nested lists.
4194 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4195 goto and handle protection regions specially in that case.
4197 If REACHABLE, we emit code, otherwise just inform the exception handling
4198 code about this finalization. */
4201 expand_cleanups (tree list, int in_fixup, int reachable)
4204 for (tail = list; tail; tail = TREE_CHAIN (tail))
4205 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4206 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
4209 if (! in_fixup && using_eh_for_cleanups_p)
4210 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4212 if (reachable && !CLEANUP_EH_ONLY (tail))
4214 /* Cleanups may be run multiple times. For example,
4215 when exiting a binding contour, we expand the
4216 cleanups associated with that contour. When a goto
4217 within that binding contour has a target outside that
4218 contour, it will expand all cleanups from its scope to
4219 the target. Though the cleanups are expanded multiple
4220 times, the control paths are non-overlapping so the
4221 cleanups will not be executed twice. */
4223 /* We may need to protect from outer cleanups. */
4224 if (in_fixup && using_eh_for_cleanups_p)
4226 expand_eh_region_start ();
4228 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4230 expand_eh_region_end_fixup (TREE_VALUE (tail));
4233 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4240 /* Mark when the context we are emitting RTL for as a conditional
4241 context, so that any cleanup actions we register with
4242 expand_decl_init will be properly conditionalized when those
4243 cleanup actions are later performed. Must be called before any
4244 expression (tree) is expanded that is within a conditional context. */
4247 start_cleanup_deferral (void)
4249 /* block_stack can be NULL if we are inside the parameter list. It is
4250 OK to do nothing, because cleanups aren't possible here. */
4252 ++block_stack->data.block.conditional_code;
4255 /* Mark the end of a conditional region of code. Because cleanup
4256 deferrals may be nested, we may still be in a conditional region
4257 after we end the currently deferred cleanups, only after we end all
4258 deferred cleanups, are we back in unconditional code. */
4261 end_cleanup_deferral (void)
4263 /* block_stack can be NULL if we are inside the parameter list. It is
4264 OK to do nothing, because cleanups aren't possible here. */
4266 --block_stack->data.block.conditional_code;
4270 last_cleanup_this_contour (void)
4272 if (block_stack == 0)
4275 return block_stack->data.block.cleanups;
4278 /* Return 1 if there are any pending cleanups at this point.
4279 Check the current contour as well as contours that enclose
4280 the current contour. */
4283 any_pending_cleanups (void)
4285 struct nesting *block;
4287 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4290 if (block_stack->data.block.cleanups != NULL)
4293 if (block_stack->data.block.outer_cleanups == 0)
4296 for (block = block_stack->next; block; block = block->next)
4297 if (block->data.block.cleanups != 0)
4303 /* Enter a case (Pascal) or switch (C) statement.
4304 Push a block onto case_stack and nesting_stack
4305 to accumulate the case-labels that are seen
4306 and to record the labels generated for the statement.
4308 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4309 Otherwise, this construct is transparent for `exit_something'.
4311 EXPR is the index-expression to be dispatched on.
4312 TYPE is its nominal type. We could simply convert EXPR to this type,
4313 but instead we take short cuts. */
4316 expand_start_case (int exit_flag, tree expr, tree type,
4317 const char *printname)
4319 struct nesting *thiscase = ALLOC_NESTING ();
4321 /* Make an entry on case_stack for the case we are entering. */
4323 thiscase->desc = CASE_NESTING;
4324 thiscase->next = case_stack;
4325 thiscase->all = nesting_stack;
4326 thiscase->depth = ++nesting_depth;
4327 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4328 thiscase->data.case_stmt.case_list = 0;
4329 thiscase->data.case_stmt.index_expr = expr;
4330 thiscase->data.case_stmt.nominal_type = type;
4331 thiscase->data.case_stmt.default_label = 0;
4332 thiscase->data.case_stmt.printname = printname;
4333 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4334 case_stack = thiscase;
4335 nesting_stack = thiscase;
4337 do_pending_stack_adjust ();
4340 /* Make sure case_stmt.start points to something that won't
4341 need any transformation before expand_end_case. */
4342 if (GET_CODE (get_last_insn ()) != NOTE)
4343 emit_note (NOTE_INSN_DELETED);
4345 thiscase->data.case_stmt.start = get_last_insn ();
4347 start_cleanup_deferral ();
4350 /* Start a "dummy case statement" within which case labels are invalid
4351 and are not connected to any larger real case statement.
4352 This can be used if you don't want to let a case statement jump
4353 into the middle of certain kinds of constructs. */
4356 expand_start_case_dummy (void)
4358 struct nesting *thiscase = ALLOC_NESTING ();
4360 /* Make an entry on case_stack for the dummy. */
4362 thiscase->desc = CASE_NESTING;
4363 thiscase->next = case_stack;
4364 thiscase->all = nesting_stack;
4365 thiscase->depth = ++nesting_depth;
4366 thiscase->exit_label = 0;
4367 thiscase->data.case_stmt.case_list = 0;
4368 thiscase->data.case_stmt.start = 0;
4369 thiscase->data.case_stmt.nominal_type = 0;
4370 thiscase->data.case_stmt.default_label = 0;
4371 case_stack = thiscase;
4372 nesting_stack = thiscase;
4373 start_cleanup_deferral ();
4377 check_seenlabel (void)
4379 /* If this is the first label, warn if any insns have been emitted. */
4380 if (case_stack->data.case_stmt.line_number_status >= 0)
4384 restore_line_number_status
4385 (case_stack->data.case_stmt.line_number_status);
4386 case_stack->data.case_stmt.line_number_status = -1;
4388 for (insn = case_stack->data.case_stmt.start;
4390 insn = NEXT_INSN (insn))
4392 if (GET_CODE (insn) == CODE_LABEL)
4394 if (GET_CODE (insn) != NOTE
4395 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4398 insn = PREV_INSN (insn);
4399 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4401 /* If insn is zero, then there must have been a syntax error. */
4405 locus.file = NOTE_SOURCE_FILE (insn);
4406 locus.line = NOTE_LINE_NUMBER (insn);
4407 warning ("%Hunreachable code at beginning of %s", &locus,
4408 case_stack->data.case_stmt.printname);
4416 /* Accumulate one case or default label inside a case or switch statement.
4417 VALUE is the value of the case (a null pointer, for a default label).
4418 The function CONVERTER, when applied to arguments T and V,
4419 converts the value V to the type T.
4421 If not currently inside a case or switch statement, return 1 and do
4422 nothing. The caller will print a language-specific error message.
4423 If VALUE is a duplicate or overlaps, return 2 and do nothing
4424 except store the (first) duplicate node in *DUPLICATE.
4425 If VALUE is out of range, return 3 and do nothing.
4426 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4427 Return 0 on success.
4429 Extended to handle range statements. */
4432 pushcase (tree value, tree (*converter) (tree, tree), tree label,
4438 /* Fail if not inside a real case statement. */
4439 if (! (case_stack && case_stack->data.case_stmt.start))
4442 if (stack_block_stack
4443 && stack_block_stack->depth > case_stack->depth)
4446 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4447 nominal_type = case_stack->data.case_stmt.nominal_type;
4449 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4450 if (index_type == error_mark_node)
4453 /* Convert VALUE to the type in which the comparisons are nominally done. */
4455 value = (*converter) (nominal_type, value);
4459 /* Fail if this value is out of range for the actual type of the index
4460 (which may be narrower than NOMINAL_TYPE). */
4462 && (TREE_CONSTANT_OVERFLOW (value)
4463 || ! int_fits_type_p (value, index_type)))
4466 return add_case_node (value, value, label, duplicate);
4469 /* Like pushcase but this case applies to all values between VALUE1 and
4470 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4471 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4472 starts at VALUE1 and ends at the highest value of the index type.
4473 If both are NULL, this case applies to all values.
4475 The return value is the same as that of pushcase but there is one
4476 additional error code: 4 means the specified range was empty. */
4479 pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree),
4480 tree label, tree *duplicate)
4485 /* Fail if not inside a real case statement. */
4486 if (! (case_stack && case_stack->data.case_stmt.start))
4489 if (stack_block_stack
4490 && stack_block_stack->depth > case_stack->depth)
4493 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4494 nominal_type = case_stack->data.case_stmt.nominal_type;
4496 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4497 if (index_type == error_mark_node)
4502 /* Convert VALUEs to type in which the comparisons are nominally done
4503 and replace any unspecified value with the corresponding bound. */
4505 value1 = TYPE_MIN_VALUE (index_type);
4507 value2 = TYPE_MAX_VALUE (index_type);
4509 /* Fail if the range is empty. Do this before any conversion since
4510 we want to allow out-of-range empty ranges. */
4511 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4514 /* If the max was unbounded, use the max of the nominal_type we are
4515 converting to. Do this after the < check above to suppress false
4518 value2 = TYPE_MAX_VALUE (nominal_type);
4520 value1 = (*converter) (nominal_type, value1);
4521 value2 = (*converter) (nominal_type, value2);
4523 /* Fail if these values are out of range. */
4524 if (TREE_CONSTANT_OVERFLOW (value1)
4525 || ! int_fits_type_p (value1, index_type))
4528 if (TREE_CONSTANT_OVERFLOW (value2)
4529 || ! int_fits_type_p (value2, index_type))
4532 return add_case_node (value1, value2, label, duplicate);
4535 /* Do the actual insertion of a case label for pushcase and pushcase_range
4536 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4537 slowdown for large switch statements. */
4540 add_case_node (tree low, tree high, tree label, tree *duplicate)
4542 struct case_node *p, **q, *r;
4544 /* If there's no HIGH value, then this is not a case range; it's
4545 just a simple case label. But that's just a degenerate case
4550 /* Handle default labels specially. */
4553 if (case_stack->data.case_stmt.default_label != 0)
4555 *duplicate = case_stack->data.case_stmt.default_label;
4558 case_stack->data.case_stmt.default_label = label;
4559 expand_label (label);
4563 q = &case_stack->data.case_stmt.case_list;
4570 /* Keep going past elements distinctly greater than HIGH. */
4571 if (tree_int_cst_lt (high, p->low))
4574 /* or distinctly less than LOW. */
4575 else if (tree_int_cst_lt (p->high, low))
4580 /* We have an overlap; this is an error. */
4581 *duplicate = p->code_label;
4586 /* Add this label to the chain, and succeed. */
4588 r = ggc_alloc (sizeof (struct case_node));
4591 /* If the bounds are equal, turn this into the one-value case. */
4592 if (tree_int_cst_equal (low, high))
4597 r->code_label = label;
4598 expand_label (label);
4608 struct case_node *s;
4614 if (! (b = p->balance))
4615 /* Growth propagation from left side. */
4622 if ((p->left = s = r->right))
4631 if ((r->parent = s))
4639 case_stack->data.case_stmt.case_list = r;
4642 /* r->balance == +1 */
4647 struct case_node *t = r->right;
4649 if ((p->left = s = t->right))
4653 if ((r->right = s = t->left))
4667 if ((t->parent = s))
4675 case_stack->data.case_stmt.case_list = t;
4682 /* p->balance == +1; growth of left side balances the node. */
4692 if (! (b = p->balance))
4693 /* Growth propagation from right side. */
4701 if ((p->right = s = r->left))
4709 if ((r->parent = s))
4718 case_stack->data.case_stmt.case_list = r;
4722 /* r->balance == -1 */
4726 struct case_node *t = r->left;
4728 if ((p->right = s = t->left))
4733 if ((r->left = s = t->right))
4747 if ((t->parent = s))
4756 case_stack->data.case_stmt.case_list = t;
4762 /* p->balance == -1; growth of right side balances the node. */
4775 /* Returns the number of possible values of TYPE.
4776 Returns -1 if the number is unknown, variable, or if the number does not
4777 fit in a HOST_WIDE_INT.
4778 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4779 do not increase monotonically (there may be duplicates);
4780 to 1 if the values increase monotonically, but not always by 1;
4781 otherwise sets it to 0. */
4784 all_cases_count (tree type, int *sparseness)
4787 HOST_WIDE_INT count, minval, lastval;
4791 switch (TREE_CODE (type))
4798 count = 1 << BITS_PER_UNIT;
4803 if (TYPE_MAX_VALUE (type) != 0
4804 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4805 TYPE_MIN_VALUE (type))))
4806 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4807 convert (type, integer_zero_node))))
4808 && host_integerp (t, 1))
4809 count = tree_low_cst (t, 1);
4815 /* Don't waste time with enumeral types with huge values. */
4816 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4817 || TYPE_MAX_VALUE (type) == 0
4818 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4821 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4824 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4826 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4828 if (*sparseness == 2 || thisval <= lastval)
4830 else if (thisval != minval + count)
4841 #define BITARRAY_TEST(ARRAY, INDEX) \
4842 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4843 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4844 #define BITARRAY_SET(ARRAY, INDEX) \
4845 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4846 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4848 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4849 with the case values we have seen, assuming the case expression
4851 SPARSENESS is as determined by all_cases_count.
4853 The time needed is proportional to COUNT, unless
4854 SPARSENESS is 2, in which case quadratic time is needed. */
4857 mark_seen_cases (tree type, unsigned char *cases_seen, HOST_WIDE_INT count,
4860 tree next_node_to_try = NULL_TREE;
4861 HOST_WIDE_INT next_node_offset = 0;
4863 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4864 tree val = make_node (INTEGER_CST);
4866 TREE_TYPE (val) = type;
4870 else if (sparseness == 2)
4873 unsigned HOST_WIDE_INT xlo;
4875 /* This less efficient loop is only needed to handle
4876 duplicate case values (multiple enum constants
4877 with the same value). */
4878 TREE_TYPE (val) = TREE_TYPE (root->low);
4879 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4880 t = TREE_CHAIN (t), xlo++)
4882 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4883 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4887 /* Keep going past elements distinctly greater than VAL. */
4888 if (tree_int_cst_lt (val, n->low))
4891 /* or distinctly less than VAL. */
4892 else if (tree_int_cst_lt (n->high, val))
4897 /* We have found a matching range. */
4898 BITARRAY_SET (cases_seen, xlo);
4908 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
4910 for (n = root; n; n = n->right)
4912 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4913 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4914 while (! tree_int_cst_lt (n->high, val))
4916 /* Calculate (into xlo) the "offset" of the integer (val).
4917 The element with lowest value has offset 0, the next smallest
4918 element has offset 1, etc. */
4920 unsigned HOST_WIDE_INT xlo;
4924 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4926 /* The TYPE_VALUES will be in increasing order, so
4927 starting searching where we last ended. */
4928 t = next_node_to_try;
4929 xlo = next_node_offset;
4935 t = TYPE_VALUES (type);
4938 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4940 next_node_to_try = TREE_CHAIN (t);
4941 next_node_offset = xlo + 1;
4946 if (t == next_node_to_try)
4955 t = TYPE_MIN_VALUE (type);
4957 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
4961 add_double (xlo, xhi,
4962 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4966 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
4967 BITARRAY_SET (cases_seen, xlo);
4969 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4971 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
4977 /* Given a switch statement with an expression that is an enumeration
4978 type, warn if any of the enumeration type's literals are not
4979 covered by the case expressions of the switch. Also, warn if there
4980 are any extra switch cases that are *not* elements of the
4985 At one stage this function would: ``If all enumeration literals
4986 were covered by the case expressions, turn one of the expressions
4987 into the default expression since it should not be possible to fall
4988 through such a switch.''
4990 That code has since been removed as: ``This optimization is
4991 disabled because it causes valid programs to fail. ANSI C does not
4992 guarantee that an expression with enum type will have a value that
4993 is the same as one of the enumeration literals.'' */
4996 check_for_full_enumeration_handling (tree type)
4998 struct case_node *n;
5001 /* True iff the selector type is a numbered set mode. */
5004 /* The number of possible selector values. */
5007 /* For each possible selector value. a one iff it has been matched
5008 by a case value alternative. */
5009 unsigned char *cases_seen;
5011 /* The allocated size of cases_seen, in chars. */
5012 HOST_WIDE_INT bytes_needed;
5014 size = all_cases_count (type, &sparseness);
5015 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5017 if (size > 0 && size < 600000
5018 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5019 this optimization if we don't have enough memory rather than
5020 aborting, as xmalloc would do. */
5021 && (cases_seen = really_call_calloc (bytes_needed, 1)) != NULL)
5024 tree v = TYPE_VALUES (type);
5026 /* The time complexity of this code is normally O(N), where
5027 N being the number of members in the enumerated type.
5028 However, if type is an ENUMERAL_TYPE whose values do not
5029 increase monotonically, O(N*log(N)) time may be needed. */
5031 mark_seen_cases (type, cases_seen, size, sparseness);
5033 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5034 if (BITARRAY_TEST (cases_seen, i) == 0)
5035 warning ("enumeration value `%s' not handled in switch",
5036 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5041 /* Now we go the other way around; we warn if there are case
5042 expressions that don't correspond to enumerators. This can
5043 occur since C and C++ don't enforce type-checking of
5044 assignments to enumeration variables. */
5046 if (case_stack->data.case_stmt.case_list
5047 && case_stack->data.case_stmt.case_list->left)
5048 case_stack->data.case_stmt.case_list
5049 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5050 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5052 for (chain = TYPE_VALUES (type);
5053 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5054 chain = TREE_CHAIN (chain))
5059 if (TYPE_NAME (type) == 0)
5060 warning ("case value `%ld' not in enumerated type",
5061 (long) TREE_INT_CST_LOW (n->low));
5063 warning ("case value `%ld' not in enumerated type `%s'",
5064 (long) TREE_INT_CST_LOW (n->low),
5065 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5068 : DECL_NAME (TYPE_NAME (type))));
5070 if (!tree_int_cst_equal (n->low, n->high))
5072 for (chain = TYPE_VALUES (type);
5073 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5074 chain = TREE_CHAIN (chain))
5079 if (TYPE_NAME (type) == 0)
5080 warning ("case value `%ld' not in enumerated type",
5081 (long) TREE_INT_CST_LOW (n->high));
5083 warning ("case value `%ld' not in enumerated type `%s'",
5084 (long) TREE_INT_CST_LOW (n->high),
5085 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5088 : DECL_NAME (TYPE_NAME (type))));
5095 /* Maximum number of case bit tests. */
5096 #define MAX_CASE_BIT_TESTS 3
5098 /* By default, enable case bit tests on targets with ashlsi3. */
5099 #ifndef CASE_USE_BIT_TESTS
5100 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5101 != CODE_FOR_nothing)
5105 /* A case_bit_test represents a set of case nodes that may be
5106 selected from using a bit-wise comparison. HI and LO hold
5107 the integer to be tested against, LABEL contains the label
5108 to jump to upon success and BITS counts the number of case
5109 nodes handled by this test, typically the number of bits
5112 struct case_bit_test
5120 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5123 bool lshift_cheap_p (void)
5125 static bool init = false;
5126 static bool cheap = true;
5130 rtx reg = gen_rtx_REG (word_mode, 10000);
5131 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5132 cheap = cost < COSTS_N_INSNS (3);
5139 /* Comparison function for qsort to order bit tests by decreasing
5140 number of case nodes, i.e. the node with the most cases gets
5144 int case_bit_test_cmp (const void *p1, const void *p2)
5146 const struct case_bit_test *d1 = p1;
5147 const struct case_bit_test *d2 = p2;
5149 return d2->bits - d1->bits;
5152 /* Expand a switch statement by a short sequence of bit-wise
5153 comparisons. "switch(x)" is effectively converted into
5154 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5157 INDEX_EXPR is the value being switched on, which is of
5158 type INDEX_TYPE. MINVAL is the lowest case value of in
5159 the case nodes, of INDEX_TYPE type, and RANGE is highest
5160 value minus MINVAL, also of type INDEX_TYPE. NODES is
5161 the set of case nodes, and DEFAULT_LABEL is the label to
5162 branch to should none of the cases match.
5164 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5168 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
5169 tree range, case_node_ptr nodes, rtx default_label)
5171 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5172 enum machine_mode mode;
5173 rtx expr, index, label;
5174 unsigned int i,j,lo,hi;
5175 struct case_node *n;
5179 for (n = nodes; n; n = n->right)
5181 label = label_rtx (n->code_label);
5182 for (i = 0; i < count; i++)
5183 if (same_case_target_p (label, test[i].label))
5188 if (count >= MAX_CASE_BIT_TESTS)
5192 test[i].label = label;
5199 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5200 n->low, minval)), 1);
5201 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5202 n->high, minval)), 1);
5203 for (j = lo; j <= hi; j++)
5204 if (j >= HOST_BITS_PER_WIDE_INT)
5205 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5207 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5210 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5212 index_expr = fold (build (MINUS_EXPR, index_type,
5213 convert (index_type, index_expr),
5214 convert (index_type, minval)));
5215 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5217 index = protect_from_queue (index, 0);
5218 do_pending_stack_adjust ();
5220 mode = TYPE_MODE (index_type);
5221 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5222 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5225 index = convert_to_mode (word_mode, index, 0);
5226 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5227 index, NULL_RTX, 1, OPTAB_WIDEN);
5229 for (i = 0; i < count; i++)
5231 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5232 expr = expand_binop (word_mode, and_optab, index, expr,
5233 NULL_RTX, 1, OPTAB_WIDEN);
5234 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5235 word_mode, 1, test[i].label);
5238 emit_jump (default_label);
5241 /* Terminate a case (Pascal) or switch (C) statement
5242 in which ORIG_INDEX is the expression to be tested.
5243 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5244 type as given in the source before any compiler conversions.
5245 Generate the code to test it and jump to the right place. */
5248 expand_end_case_type (tree orig_index, tree orig_type)
5250 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5251 rtx default_label = 0;
5252 struct case_node *n, *m;
5253 unsigned int count, uniq;
5259 rtx before_case, end, lab;
5260 struct nesting *thiscase = case_stack;
5261 tree index_expr, index_type;
5262 bool exit_done = false;
5265 /* Don't crash due to previous errors. */
5266 if (thiscase == NULL)
5269 index_expr = thiscase->data.case_stmt.index_expr;
5270 index_type = TREE_TYPE (index_expr);
5271 unsignedp = TREE_UNSIGNED (index_type);
5272 if (orig_type == NULL)
5273 orig_type = TREE_TYPE (orig_index);
5275 do_pending_stack_adjust ();
5277 /* This might get a spurious warning in the presence of a syntax error;
5278 it could be fixed by moving the call to check_seenlabel after the
5279 check for error_mark_node, and copying the code of check_seenlabel that
5280 deals with case_stack->data.case_stmt.line_number_status /
5281 restore_line_number_status in front of the call to end_cleanup_deferral;
5282 However, this might miss some useful warnings in the presence of
5283 non-syntax errors. */
5286 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5287 if (index_type != error_mark_node)
5289 /* If the switch expression was an enumerated type, check that
5290 exactly all enumeration literals are covered by the cases.
5291 The check is made when -Wswitch was specified and there is no
5292 default case, or when -Wswitch-enum was specified. */
5293 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5294 || warn_switch_enum)
5295 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5296 && TREE_CODE (index_expr) != INTEGER_CST)
5297 check_for_full_enumeration_handling (orig_type);
5299 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5300 warning ("switch missing default case");
5302 /* If we don't have a default-label, create one here,
5303 after the body of the switch. */
5304 if (thiscase->data.case_stmt.default_label == 0)
5306 thiscase->data.case_stmt.default_label
5307 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5308 /* Share the exit label if possible. */
5309 if (thiscase->exit_label)
5311 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5312 thiscase->exit_label);
5315 expand_label (thiscase->data.case_stmt.default_label);
5317 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5319 before_case = get_last_insn ();
5321 if (thiscase->data.case_stmt.case_list
5322 && thiscase->data.case_stmt.case_list->left)
5323 thiscase->data.case_stmt.case_list
5324 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5326 /* Simplify the case-list before we count it. */
5327 group_case_nodes (thiscase->data.case_stmt.case_list);
5328 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5331 /* Get upper and lower bounds of case values.
5332 Also convert all the case values to the index expr's data type. */
5336 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5338 /* Check low and high label values are integers. */
5339 if (TREE_CODE (n->low) != INTEGER_CST)
5341 if (TREE_CODE (n->high) != INTEGER_CST)
5344 n->low = convert (index_type, n->low);
5345 n->high = convert (index_type, n->high);
5347 /* Count the elements and track the largest and smallest
5348 of them (treating them as signed even if they are not). */
5356 if (INT_CST_LT (n->low, minval))
5358 if (INT_CST_LT (maxval, n->high))
5361 /* A range counts double, since it requires two compares. */
5362 if (! tree_int_cst_equal (n->low, n->high))
5365 /* Count the number of unique case node targets. */
5367 lab = label_rtx (n->code_label);
5368 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5369 if (same_case_target_p (label_rtx (m->code_label), lab))
5376 /* Compute span of values. */
5378 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5380 end_cleanup_deferral ();
5384 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5386 emit_jump (default_label);
5389 /* Try implementing this switch statement by a short sequence of
5390 bit-wise comparisons. However, we let the binary-tree case
5391 below handle constant index expressions. */
5392 else if (CASE_USE_BIT_TESTS
5393 && ! TREE_CONSTANT (index_expr)
5394 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5395 && compare_tree_int (range, 0) > 0
5396 && lshift_cheap_p ()
5397 && ((uniq == 1 && count >= 3)
5398 || (uniq == 2 && count >= 5)
5399 || (uniq == 3 && count >= 6)))
5401 /* Optimize the case where all the case values fit in a
5402 word without having to subtract MINVAL. In this case,
5403 we can optimize away the subtraction. */
5404 if (compare_tree_int (minval, 0) > 0
5405 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5407 minval = integer_zero_node;
5410 emit_case_bit_tests (index_type, index_expr, minval, range,
5411 thiscase->data.case_stmt.case_list,
5415 /* If range of values is much bigger than number of values,
5416 make a sequence of conditional branches instead of a dispatch.
5417 If the switch-index is a constant, do it this way
5418 because we can optimize it. */
5420 else if (count < case_values_threshold ()
5421 || compare_tree_int (range,
5422 (optimize_size ? 3 : 10) * count) > 0
5423 /* RANGE may be signed, and really large ranges will show up
5424 as negative numbers. */
5425 || compare_tree_int (range, 0) < 0
5426 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5429 || TREE_CONSTANT (index_expr))
5431 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5433 /* If the index is a short or char that we do not have
5434 an insn to handle comparisons directly, convert it to
5435 a full integer now, rather than letting each comparison
5436 generate the conversion. */
5438 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5439 && ! have_insn_for (COMPARE, GET_MODE (index)))
5441 enum machine_mode wider_mode;
5442 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5443 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5444 if (have_insn_for (COMPARE, wider_mode))
5446 index = convert_to_mode (wider_mode, index, unsignedp);
5452 do_pending_stack_adjust ();
5454 index = protect_from_queue (index, 0);
5455 if (GET_CODE (index) == MEM)
5456 index = copy_to_reg (index);
5457 if (GET_CODE (index) == CONST_INT
5458 || TREE_CODE (index_expr) == INTEGER_CST)
5460 /* Make a tree node with the proper constant value
5461 if we don't already have one. */
5462 if (TREE_CODE (index_expr) != INTEGER_CST)
5465 = build_int_2 (INTVAL (index),
5466 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5467 index_expr = convert (index_type, index_expr);
5470 /* For constant index expressions we need only
5471 issue an unconditional branch to the appropriate
5472 target code. The job of removing any unreachable
5473 code is left to the optimization phase if the
5474 "-O" option is specified. */
5475 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5476 if (! tree_int_cst_lt (index_expr, n->low)
5477 && ! tree_int_cst_lt (n->high, index_expr))
5481 emit_jump (label_rtx (n->code_label));
5483 emit_jump (default_label);
5487 /* If the index expression is not constant we generate
5488 a binary decision tree to select the appropriate
5489 target code. This is done as follows:
5491 The list of cases is rearranged into a binary tree,
5492 nearly optimal assuming equal probability for each case.
5494 The tree is transformed into RTL, eliminating
5495 redundant test conditions at the same time.
5497 If program flow could reach the end of the
5498 decision tree an unconditional jump to the
5499 default code is emitted. */
5502 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5503 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5504 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5505 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5506 default_label, index_type);
5507 emit_jump_if_reachable (default_label);
5512 table_label = gen_label_rtx ();
5513 if (! try_casesi (index_type, index_expr, minval, range,
5514 table_label, default_label))
5516 index_type = thiscase->data.case_stmt.nominal_type;
5518 /* Index jumptables from zero for suitable values of
5519 minval to avoid a subtraction. */
5521 && compare_tree_int (minval, 0) > 0
5522 && compare_tree_int (minval, 3) < 0)
5524 minval = integer_zero_node;
5528 if (! try_tablejump (index_type, index_expr, minval, range,
5529 table_label, default_label))
5533 /* Get table of labels to jump to, in order of case index. */
5535 ncases = tree_low_cst (range, 0) + 1;
5536 labelvec = alloca (ncases * sizeof (rtx));
5537 memset (labelvec, 0, ncases * sizeof (rtx));
5539 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5541 /* Compute the low and high bounds relative to the minimum
5542 value since that should fit in a HOST_WIDE_INT while the
5543 actual values may not. */
5545 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5546 n->low, minval)), 1);
5547 HOST_WIDE_INT i_high
5548 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5549 n->high, minval)), 1);
5552 for (i = i_low; i <= i_high; i ++)
5554 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5557 /* Fill in the gaps with the default. */
5558 for (i = 0; i < ncases; i++)
5559 if (labelvec[i] == 0)
5560 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5562 /* Output the table. */
5563 emit_label (table_label);
5565 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5566 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5567 gen_rtx_LABEL_REF (Pmode, table_label),
5568 gen_rtvec_v (ncases, labelvec),
5569 const0_rtx, const0_rtx));
5571 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5572 gen_rtvec_v (ncases, labelvec)));
5574 /* If the case insn drops through the table,
5575 after the table we must jump to the default-label.
5576 Otherwise record no drop-through after the table. */
5577 #ifdef CASE_DROPS_THROUGH
5578 emit_jump (default_label);
5584 before_case = NEXT_INSN (before_case);
5585 end = get_last_insn ();
5586 if (squeeze_notes (&before_case, &end))
5588 reorder_insns (before_case, end,
5589 thiscase->data.case_stmt.start);
5592 end_cleanup_deferral ();
5594 if (thiscase->exit_label && !exit_done)
5595 emit_label (thiscase->exit_label);
5597 POPSTACK (case_stack);
5602 /* Convert the tree NODE into a list linked by the right field, with the left
5603 field zeroed. RIGHT is used for recursion; it is a list to be placed
5604 rightmost in the resulting list. */
5606 static struct case_node *
5607 case_tree2list (struct case_node *node, struct case_node *right)
5609 struct case_node *left;
5612 right = case_tree2list (node->right, right);
5614 node->right = right;
5615 if ((left = node->left))
5618 return case_tree2list (left, node);
5624 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5627 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
5629 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5635 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5636 (GET_MODE (op1) == VOIDmode
5637 ? GET_MODE (op2) : GET_MODE (op1)),
5641 /* Not all case values are encountered equally. This function
5642 uses a heuristic to weight case labels, in cases where that
5643 looks like a reasonable thing to do.
5645 Right now, all we try to guess is text, and we establish the
5648 chars above space: 16
5657 If we find any cases in the switch that are not either -1 or in the range
5658 of valid ASCII characters, or are control characters other than those
5659 commonly used with "\", don't treat this switch scanning text.
5661 Return 1 if these nodes are suitable for cost estimation, otherwise
5665 estimate_case_costs (case_node_ptr node)
5667 tree min_ascii = integer_minus_one_node;
5668 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5672 /* If we haven't already made the cost table, make it now. Note that the
5673 lower bound of the table is -1, not zero. */
5675 if (! cost_table_initialized)
5677 cost_table_initialized = 1;
5679 for (i = 0; i < 128; i++)
5682 COST_TABLE (i) = 16;
5683 else if (ISPUNCT (i))
5685 else if (ISCNTRL (i))
5686 COST_TABLE (i) = -1;
5689 COST_TABLE (' ') = 8;
5690 COST_TABLE ('\t') = 4;
5691 COST_TABLE ('\0') = 4;
5692 COST_TABLE ('\n') = 2;
5693 COST_TABLE ('\f') = 1;
5694 COST_TABLE ('\v') = 1;
5695 COST_TABLE ('\b') = 1;
5698 /* See if all the case expressions look like text. It is text if the
5699 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5700 as signed arithmetic since we don't want to ever access cost_table with a
5701 value less than -1. Also check that none of the constants in a range
5702 are strange control characters. */
5704 for (n = node; n; n = n->right)
5706 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5709 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5710 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5711 if (COST_TABLE (i) < 0)
5715 /* All interesting values are within the range of interesting
5716 ASCII characters. */
5720 /* Determine whether two case labels branch to the same target. */
5723 same_case_target_p (rtx l1, rtx l2)
5730 i1 = next_real_insn (l1);
5731 i2 = next_real_insn (l2);
5735 if (i1 && simplejump_p (i1))
5737 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
5740 if (i2 && simplejump_p (i2))
5742 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
5747 /* Delete nodes that branch to the default label from a list of
5748 case nodes. Eg. case 5: default: becomes just default: */
5751 strip_default_case_nodes (case_node_ptr *prev, rtx deflab)
5758 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
5765 /* Scan an ordered list of case nodes
5766 combining those with consecutive values or ranges.
5768 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5771 group_case_nodes (case_node_ptr head)
5773 case_node_ptr node = head;
5777 rtx lab = label_rtx (node->code_label);
5778 case_node_ptr np = node;
5780 /* Try to group the successors of NODE with NODE. */
5781 while (((np = np->right) != 0)
5782 /* Do they jump to the same place? */
5783 && same_case_target_p (label_rtx (np->code_label), lab)
5784 /* Are their ranges consecutive? */
5785 && tree_int_cst_equal (np->low,
5786 fold (build (PLUS_EXPR,
5787 TREE_TYPE (node->high),
5790 /* An overflow is not consecutive. */
5791 && tree_int_cst_lt (node->high,
5792 fold (build (PLUS_EXPR,
5793 TREE_TYPE (node->high),
5795 integer_one_node))))
5797 node->high = np->high;
5799 /* NP is the first node after NODE which can't be grouped with it.
5800 Delete the nodes in between, and move on to that node. */
5806 /* Take an ordered list of case nodes
5807 and transform them into a near optimal binary tree,
5808 on the assumption that any target code selection value is as
5809 likely as any other.
5811 The transformation is performed by splitting the ordered
5812 list into two equal sections plus a pivot. The parts are
5813 then attached to the pivot as left and right branches. Each
5814 branch is then transformed recursively. */
5817 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
5830 /* Count the number of entries on branch. Also count the ranges. */
5834 if (!tree_int_cst_equal (np->low, np->high))
5838 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5842 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5850 /* Split this list if it is long enough for that to help. */
5855 /* Find the place in the list that bisects the list's total cost,
5856 Here I gets half the total cost. */
5861 /* Skip nodes while their cost does not reach that amount. */
5862 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5863 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5864 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5867 npp = &(*npp)->right;
5872 /* Leave this branch lopsided, but optimize left-hand
5873 side and fill in `parent' fields for right-hand side. */
5875 np->parent = parent;
5876 balance_case_nodes (&np->left, np);
5877 for (; np->right; np = np->right)
5878 np->right->parent = np;
5882 /* If there are just three nodes, split at the middle one. */
5884 npp = &(*npp)->right;
5887 /* Find the place in the list that bisects the list's total cost,
5888 where ranges count as 2.
5889 Here I gets half the total cost. */
5890 i = (i + ranges + 1) / 2;
5893 /* Skip nodes while their cost does not reach that amount. */
5894 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5899 npp = &(*npp)->right;
5904 np->parent = parent;
5907 /* Optimize each of the two split parts. */
5908 balance_case_nodes (&np->left, np);
5909 balance_case_nodes (&np->right, np);
5913 /* Else leave this branch as one level,
5914 but fill in `parent' fields. */
5916 np->parent = parent;
5917 for (; np->right; np = np->right)
5918 np->right->parent = np;
5923 /* Search the parent sections of the case node tree
5924 to see if a test for the lower bound of NODE would be redundant.
5925 INDEX_TYPE is the type of the index expression.
5927 The instructions to generate the case decision tree are
5928 output in the same order as nodes are processed so it is
5929 known that if a parent node checks the range of the current
5930 node minus one that the current node is bounded at its lower
5931 span. Thus the test would be redundant. */
5934 node_has_low_bound (case_node_ptr node, tree index_type)
5937 case_node_ptr pnode;
5939 /* If the lower bound of this node is the lowest value in the index type,
5940 we need not test it. */
5942 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5945 /* If this node has a left branch, the value at the left must be less
5946 than that at this node, so it cannot be bounded at the bottom and
5947 we need not bother testing any further. */
5952 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5953 node->low, integer_one_node));
5955 /* If the subtraction above overflowed, we can't verify anything.
5956 Otherwise, look for a parent that tests our value - 1. */
5958 if (! tree_int_cst_lt (low_minus_one, node->low))
5961 for (pnode = node->parent; pnode; pnode = pnode->parent)
5962 if (tree_int_cst_equal (low_minus_one, pnode->high))
5968 /* Search the parent sections of the case node tree
5969 to see if a test for the upper bound of NODE would be redundant.
5970 INDEX_TYPE is the type of the index expression.
5972 The instructions to generate the case decision tree are
5973 output in the same order as nodes are processed so it is
5974 known that if a parent node checks the range of the current
5975 node plus one that the current node is bounded at its upper
5976 span. Thus the test would be redundant. */
5979 node_has_high_bound (case_node_ptr node, tree index_type)
5982 case_node_ptr pnode;
5984 /* If there is no upper bound, obviously no test is needed. */
5986 if (TYPE_MAX_VALUE (index_type) == NULL)
5989 /* If the upper bound of this node is the highest value in the type
5990 of the index expression, we need not test against it. */
5992 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5995 /* If this node has a right branch, the value at the right must be greater
5996 than that at this node, so it cannot be bounded at the top and
5997 we need not bother testing any further. */
6002 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6003 node->high, integer_one_node));
6005 /* If the addition above overflowed, we can't verify anything.
6006 Otherwise, look for a parent that tests our value + 1. */
6008 if (! tree_int_cst_lt (node->high, high_plus_one))
6011 for (pnode = node->parent; pnode; pnode = pnode->parent)
6012 if (tree_int_cst_equal (high_plus_one, pnode->low))
6018 /* Search the parent sections of the
6019 case node tree to see if both tests for the upper and lower
6020 bounds of NODE would be redundant. */
6023 node_is_bounded (case_node_ptr node, tree index_type)
6025 return (node_has_low_bound (node, index_type)
6026 && node_has_high_bound (node, index_type));
6029 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6032 emit_jump_if_reachable (rtx label)
6034 if (GET_CODE (get_last_insn ()) != BARRIER)
6038 /* Emit step-by-step code to select a case for the value of INDEX.
6039 The thus generated decision tree follows the form of the
6040 case-node binary tree NODE, whose nodes represent test conditions.
6041 INDEX_TYPE is the type of the index of the switch.
6043 Care is taken to prune redundant tests from the decision tree
6044 by detecting any boundary conditions already checked by
6045 emitted rtx. (See node_has_high_bound, node_has_low_bound
6046 and node_is_bounded, above.)
6048 Where the test conditions can be shown to be redundant we emit
6049 an unconditional jump to the target code. As a further
6050 optimization, the subordinates of a tree node are examined to
6051 check for bounded nodes. In this case conditional and/or
6052 unconditional jumps as a result of the boundary check for the
6053 current node are arranged to target the subordinates associated
6054 code for out of bound conditions on the current node.
6056 We can assume that when control reaches the code generated here,
6057 the index value has already been compared with the parents
6058 of this node, and determined to be on the same side of each parent
6059 as this node is. Thus, if this node tests for the value 51,
6060 and a parent tested for 52, we don't need to consider
6061 the possibility of a value greater than 51. If another parent
6062 tests for the value 50, then this node need not test anything. */
6065 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
6068 /* If INDEX has an unsigned type, we must make unsigned branches. */
6069 int unsignedp = TREE_UNSIGNED (index_type);
6070 enum machine_mode mode = GET_MODE (index);
6071 enum machine_mode imode = TYPE_MODE (index_type);
6073 /* See if our parents have already tested everything for us.
6074 If they have, emit an unconditional jump for this node. */
6075 if (node_is_bounded (node, index_type))
6076 emit_jump (label_rtx (node->code_label));
6078 else if (tree_int_cst_equal (node->low, node->high))
6080 /* Node is single valued. First see if the index expression matches
6081 this node and then check our children, if any. */
6083 do_jump_if_equal (index,
6084 convert_modes (mode, imode,
6085 expand_expr (node->low, NULL_RTX,
6088 label_rtx (node->code_label), unsignedp);
6090 if (node->right != 0 && node->left != 0)
6092 /* This node has children on both sides.
6093 Dispatch to one side or the other
6094 by comparing the index value with this node's value.
6095 If one subtree is bounded, check that one first,
6096 so we can avoid real branches in the tree. */
6098 if (node_is_bounded (node->right, index_type))
6100 emit_cmp_and_jump_insns (index,
6103 expand_expr (node->high, NULL_RTX,
6106 GT, NULL_RTX, mode, unsignedp,
6107 label_rtx (node->right->code_label));
6108 emit_case_nodes (index, node->left, default_label, index_type);
6111 else if (node_is_bounded (node->left, index_type))
6113 emit_cmp_and_jump_insns (index,
6116 expand_expr (node->high, NULL_RTX,
6119 LT, NULL_RTX, mode, unsignedp,
6120 label_rtx (node->left->code_label));
6121 emit_case_nodes (index, node->right, default_label, index_type);
6126 /* Neither node is bounded. First distinguish the two sides;
6127 then emit the code for one side at a time. */
6129 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6131 /* See if the value is on the right. */
6132 emit_cmp_and_jump_insns (index,
6135 expand_expr (node->high, NULL_RTX,
6138 GT, NULL_RTX, mode, unsignedp,
6139 label_rtx (test_label));
6141 /* Value must be on the left.
6142 Handle the left-hand subtree. */
6143 emit_case_nodes (index, node->left, default_label, index_type);
6144 /* If left-hand subtree does nothing,
6146 emit_jump_if_reachable (default_label);
6148 /* Code branches here for the right-hand subtree. */
6149 expand_label (test_label);
6150 emit_case_nodes (index, node->right, default_label, index_type);
6154 else if (node->right != 0 && node->left == 0)
6156 /* Here we have a right child but no left so we issue conditional
6157 branch to default and process the right child.
6159 Omit the conditional branch to default if we it avoid only one
6160 right child; it costs too much space to save so little time. */
6162 if (node->right->right || node->right->left
6163 || !tree_int_cst_equal (node->right->low, node->right->high))
6165 if (!node_has_low_bound (node, index_type))
6167 emit_cmp_and_jump_insns (index,
6170 expand_expr (node->high, NULL_RTX,
6173 LT, NULL_RTX, mode, unsignedp,
6177 emit_case_nodes (index, node->right, default_label, index_type);
6180 /* We cannot process node->right normally
6181 since we haven't ruled out the numbers less than
6182 this node's value. So handle node->right explicitly. */
6183 do_jump_if_equal (index,
6186 expand_expr (node->right->low, NULL_RTX,
6189 label_rtx (node->right->code_label), unsignedp);
6192 else if (node->right == 0 && node->left != 0)
6194 /* Just one subtree, on the left. */
6195 if (node->left->left || node->left->right
6196 || !tree_int_cst_equal (node->left->low, node->left->high))
6198 if (!node_has_high_bound (node, index_type))
6200 emit_cmp_and_jump_insns (index,
6203 expand_expr (node->high, NULL_RTX,
6206 GT, NULL_RTX, mode, unsignedp,
6210 emit_case_nodes (index, node->left, default_label, index_type);
6213 /* We cannot process node->left normally
6214 since we haven't ruled out the numbers less than
6215 this node's value. So handle node->left explicitly. */
6216 do_jump_if_equal (index,
6219 expand_expr (node->left->low, NULL_RTX,
6222 label_rtx (node->left->code_label), unsignedp);
6227 /* Node is a range. These cases are very similar to those for a single
6228 value, except that we do not start by testing whether this node
6229 is the one to branch to. */
6231 if (node->right != 0 && node->left != 0)
6233 /* Node has subtrees on both sides.
6234 If the right-hand subtree is bounded,
6235 test for it first, since we can go straight there.
6236 Otherwise, we need to make a branch in the control structure,
6237 then handle the two subtrees. */
6238 tree test_label = 0;
6240 if (node_is_bounded (node->right, index_type))
6241 /* Right hand node is fully bounded so we can eliminate any
6242 testing and branch directly to the target code. */
6243 emit_cmp_and_jump_insns (index,
6246 expand_expr (node->high, NULL_RTX,
6249 GT, NULL_RTX, mode, unsignedp,
6250 label_rtx (node->right->code_label));
6253 /* Right hand node requires testing.
6254 Branch to a label where we will handle it later. */
6256 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6257 emit_cmp_and_jump_insns (index,
6260 expand_expr (node->high, NULL_RTX,
6263 GT, NULL_RTX, mode, unsignedp,
6264 label_rtx (test_label));
6267 /* Value belongs to this node or to the left-hand subtree. */
6269 emit_cmp_and_jump_insns (index,
6272 expand_expr (node->low, NULL_RTX,
6275 GE, NULL_RTX, mode, unsignedp,
6276 label_rtx (node->code_label));
6278 /* Handle the left-hand subtree. */
6279 emit_case_nodes (index, node->left, default_label, index_type);
6281 /* If right node had to be handled later, do that now. */
6285 /* If the left-hand subtree fell through,
6286 don't let it fall into the right-hand subtree. */
6287 emit_jump_if_reachable (default_label);
6289 expand_label (test_label);
6290 emit_case_nodes (index, node->right, default_label, index_type);
6294 else if (node->right != 0 && node->left == 0)
6296 /* Deal with values to the left of this node,
6297 if they are possible. */
6298 if (!node_has_low_bound (node, index_type))
6300 emit_cmp_and_jump_insns (index,
6303 expand_expr (node->low, NULL_RTX,
6306 LT, NULL_RTX, mode, unsignedp,
6310 /* Value belongs to this node or to the right-hand subtree. */
6312 emit_cmp_and_jump_insns (index,
6315 expand_expr (node->high, NULL_RTX,
6318 LE, NULL_RTX, mode, unsignedp,
6319 label_rtx (node->code_label));
6321 emit_case_nodes (index, node->right, default_label, index_type);
6324 else if (node->right == 0 && node->left != 0)
6326 /* Deal with values to the right of this node,
6327 if they are possible. */
6328 if (!node_has_high_bound (node, index_type))
6330 emit_cmp_and_jump_insns (index,
6333 expand_expr (node->high, NULL_RTX,
6336 GT, NULL_RTX, mode, unsignedp,
6340 /* Value belongs to this node or to the left-hand subtree. */
6342 emit_cmp_and_jump_insns (index,
6345 expand_expr (node->low, NULL_RTX,
6348 GE, NULL_RTX, mode, unsignedp,
6349 label_rtx (node->code_label));
6351 emit_case_nodes (index, node->left, default_label, index_type);
6356 /* Node has no children so we check low and high bounds to remove
6357 redundant tests. Only one of the bounds can exist,
6358 since otherwise this node is bounded--a case tested already. */
6359 int high_bound = node_has_high_bound (node, index_type);
6360 int low_bound = node_has_low_bound (node, index_type);
6362 if (!high_bound && low_bound)
6364 emit_cmp_and_jump_insns (index,
6367 expand_expr (node->high, NULL_RTX,
6370 GT, NULL_RTX, mode, unsignedp,
6374 else if (!low_bound && high_bound)
6376 emit_cmp_and_jump_insns (index,
6379 expand_expr (node->low, NULL_RTX,
6382 LT, NULL_RTX, mode, unsignedp,
6385 else if (!low_bound && !high_bound)
6387 /* Widen LOW and HIGH to the same width as INDEX. */
6388 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6389 tree low = build1 (CONVERT_EXPR, type, node->low);
6390 tree high = build1 (CONVERT_EXPR, type, node->high);
6391 rtx low_rtx, new_index, new_bound;
6393 /* Instead of doing two branches, emit one unsigned branch for
6394 (index-low) > (high-low). */
6395 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6396 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6397 NULL_RTX, unsignedp,
6399 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6403 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6404 mode, 1, default_label);
6407 emit_jump (label_rtx (node->code_label));
6412 #include "gt-stmt.h"