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"
61 /* Assume that case vectors are not pc-relative. */
62 #ifndef CASE_VECTOR_PC_RELATIVE
63 #define CASE_VECTOR_PC_RELATIVE 0
66 /* Functions and data structures for expanding case statements. */
68 /* Case label structure, used to hold info on labels within case
69 statements. We handle "range" labels; for a single-value label
70 as in C, the high and low limits are the same.
72 An AVL tree of case nodes is initially created, and later transformed
73 to a list linked via the RIGHT fields in the nodes. Nodes with
74 higher case values are later in the list.
76 Switch statements can be output in one of two forms. A branch table
77 is used if there are more than a few labels and the labels are dense
78 within the range between the smallest and largest case value. If a
79 branch table is used, no further manipulations are done with the case
82 The alternative to the use of a branch table is to generate a series
83 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
84 and PARENT fields to hold a binary tree. Initially the tree is
85 totally unbalanced, with everything on the right. We balance the tree
86 with nodes on the left having lower case values than the parent
87 and nodes on the right having higher values. We then output the tree
90 struct case_node GTY(())
92 struct case_node *left; /* Left son in binary tree */
93 struct case_node *right; /* Right son in binary tree; also node chain */
94 struct case_node *parent; /* Parent of node in binary tree */
95 tree low; /* Lowest index value for this label */
96 tree high; /* Highest index value for this label */
97 tree code_label; /* Label to jump to when node matches */
101 typedef struct case_node case_node;
102 typedef struct case_node *case_node_ptr;
104 /* These are used by estimate_case_costs and balance_case_nodes. */
106 /* This must be a signed type, and non-ANSI compilers lack signed char. */
107 static short cost_table_[129];
108 static int use_cost_table;
109 static int cost_table_initialized;
111 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
113 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
115 /* Stack of control and binding constructs we are currently inside.
117 These constructs begin when you call `expand_start_WHATEVER'
118 and end when you call `expand_end_WHATEVER'. This stack records
119 info about how the construct began that tells the end-function
120 what to do. It also may provide information about the construct
121 to alter the behavior of other constructs within the body.
122 For example, they may affect the behavior of C `break' and `continue'.
124 Each construct gets one `struct nesting' object.
125 All of these objects are chained through the `all' field.
126 `nesting_stack' points to the first object (innermost construct).
127 The position of an entry on `nesting_stack' is in its `depth' field.
129 Each type of construct has its own individual stack.
130 For example, loops have `loop_stack'. Each object points to the
131 next object of the same type through the `next' field.
133 Some constructs are visible to `break' exit-statements and others
134 are not. Which constructs are visible depends on the language.
135 Therefore, the data structure allows each construct to be visible
136 or not, according to the args given when the construct is started.
137 The construct is visible if the `exit_label' field is non-null.
138 In that case, the value should be a CODE_LABEL rtx. */
140 struct nesting GTY(())
143 struct nesting *next;
154 /* For conds (if-then and if-then-else statements). */
157 /* Label for the end of the if construct.
158 There is none if EXITFLAG was not set
159 and no `else' has been seen yet. */
161 /* Label for the end of this alternative.
162 This may be the end of the if or the next else/elseif. */
164 } GTY ((tag ("COND_NESTING"))) cond;
168 /* Label at the top of the loop; place to loop back to. */
170 /* Label at the end of the whole construct. */
172 /* Label for `continue' statement to jump to;
173 this is in front of the stepper of the loop. */
175 } GTY ((tag ("LOOP_NESTING"))) loop;
176 /* For variable binding contours. */
179 /* Sequence number of this binding contour within the function,
180 in order of entry. */
181 int block_start_count;
182 /* Nonzero => value to restore stack to on exit. */
184 /* The NOTE that starts this contour.
185 Used by expand_goto to check whether the destination
186 is within each contour or not. */
188 /* Innermost containing binding contour that has a stack level. */
189 struct nesting *innermost_stack_block;
190 /* List of cleanups to be run on exit from this contour.
191 This is a list of expressions to be evaluated.
192 The TREE_PURPOSE of each link is the ..._DECL node
193 which the cleanup pertains to. */
195 /* List of cleanup-lists of blocks containing this block,
196 as they were at the locus where this block appears.
197 There is an element for each containing block,
198 ordered innermost containing block first.
199 The tail of this list can be 0,
200 if all remaining elements would be empty lists.
201 The element's TREE_VALUE is the cleanup-list of that block,
202 which may be null. */
204 /* Chain of labels defined inside this binding contour.
205 For contours that have stack levels or cleanups. */
206 struct label_chain *label_chain;
207 /* Nonzero if this is associated with an EH region. */
208 int exception_region;
209 /* The saved target_temp_slot_level from our outer block.
210 We may reset target_temp_slot_level to be the level of
211 this block, if that is done, target_temp_slot_level
212 reverts to the saved target_temp_slot_level at the very
214 int block_target_temp_slot_level;
215 /* True if we are currently emitting insns in an area of
216 output code that is controlled by a conditional
217 expression. This is used by the cleanup handling code to
218 generate conditional cleanup actions. */
219 int conditional_code;
220 /* A place to move the start of the exception region for any
221 of the conditional cleanups, must be at the end or after
222 the start of the last unconditional cleanup, and before any
223 conditional branch points. */
224 rtx last_unconditional_cleanup;
225 } GTY ((tag ("BLOCK_NESTING"))) block;
226 /* For switch (C) or case (Pascal) statements,
227 and also for dummies (see `expand_start_case_dummy'). */
230 /* The insn after which the case dispatch should finally
231 be emitted. Zero for a dummy. */
233 /* A list of case labels; it is first built as an AVL tree.
234 During expand_end_case, this is converted to a list, and may be
235 rearranged into a nearly balanced binary tree. */
236 struct case_node *case_list;
237 /* Label to jump to if no case matches. */
239 /* The expression to be dispatched on. */
241 /* Type that INDEX_EXPR should be converted to. */
243 /* Name of this kind of statement, for warnings. */
244 const char *printname;
245 /* Used to save no_line_numbers till we see the first case label.
246 We set this to -1 when we see the first case label in this
248 int line_number_status;
249 } GTY ((tag ("CASE_NESTING"))) case_stmt;
250 } GTY ((desc ("%1.desc"))) data;
253 /* Allocate and return a new `struct nesting'. */
255 #define ALLOC_NESTING() ggc_alloc (sizeof (struct nesting))
257 /* Pop the nesting stack element by element until we pop off
258 the element which is at the top of STACK.
259 Update all the other stacks, popping off elements from them
260 as we pop them from nesting_stack. */
262 #define POPSTACK(STACK) \
263 do { struct nesting *target = STACK; \
264 struct nesting *this; \
265 do { this = nesting_stack; \
266 if (loop_stack == this) \
267 loop_stack = loop_stack->next; \
268 if (cond_stack == this) \
269 cond_stack = cond_stack->next; \
270 if (block_stack == this) \
271 block_stack = block_stack->next; \
272 if (stack_block_stack == this) \
273 stack_block_stack = stack_block_stack->next; \
274 if (case_stack == this) \
275 case_stack = case_stack->next; \
276 nesting_depth = nesting_stack->depth - 1; \
277 nesting_stack = this->all; } \
278 while (this != target); } while (0)
280 /* In some cases it is impossible to generate code for a forward goto
281 until the label definition is seen. This happens when it may be necessary
282 for the goto to reset the stack pointer: we don't yet know how to do that.
283 So expand_goto puts an entry on this fixup list.
284 Each time a binding contour that resets the stack is exited,
286 If the target label has now been defined, we can insert the proper code. */
288 struct goto_fixup GTY(())
290 /* Points to following fixup. */
291 struct goto_fixup *next;
292 /* Points to the insn before the jump insn.
293 If more code must be inserted, it goes after this insn. */
295 /* The LABEL_DECL that this jump is jumping to, or 0
296 for break, continue or return. */
298 /* The BLOCK for the place where this goto was found. */
300 /* The CODE_LABEL rtx that this is jumping to. */
302 /* Number of binding contours started in current function
303 before the label reference. */
304 int block_start_count;
305 /* The outermost stack level that should be restored for this jump.
306 Each time a binding contour that resets the stack is exited,
307 if the target label is *not* yet defined, this slot is updated. */
309 /* List of lists of cleanup expressions to be run by this goto.
310 There is one element for each block that this goto is within.
311 The tail of this list can be 0,
312 if all remaining elements would be empty.
313 The TREE_VALUE contains the cleanup list of that block as of the
314 time this goto was seen.
315 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
316 tree cleanup_list_list;
319 /* Within any binding contour that must restore a stack level,
320 all labels are recorded with a chain of these structures. */
322 struct label_chain GTY(())
324 /* Points to following fixup. */
325 struct label_chain *next;
329 struct stmt_status GTY(())
331 /* Chain of all pending binding contours. */
332 struct nesting * x_block_stack;
334 /* If any new stacks are added here, add them to POPSTACKS too. */
336 /* Chain of all pending binding contours that restore stack levels
338 struct nesting * x_stack_block_stack;
340 /* Chain of all pending conditional statements. */
341 struct nesting * x_cond_stack;
343 /* Chain of all pending loops. */
344 struct nesting * x_loop_stack;
346 /* Chain of all pending case or switch statements. */
347 struct nesting * x_case_stack;
349 /* Separate chain including all of the above,
350 chained through the `all' field. */
351 struct nesting * x_nesting_stack;
353 /* Number of entries on nesting_stack now. */
356 /* Number of binding contours started so far in this function. */
357 int x_block_start_count;
359 /* Each time we expand an expression-statement,
360 record the expr's type and its RTL value here. */
361 tree x_last_expr_type;
362 rtx x_last_expr_value;
364 /* Nonzero if within a ({...}) grouping, in which case we must
365 always compute a value for each expr-stmt in case it is the last one. */
366 int x_expr_stmts_for_value;
368 /* Location of last line-number note, whether we actually
369 emitted it or not. */
370 location_t x_emit_locus;
372 struct goto_fixup *x_goto_fixup_chain;
375 #define block_stack (cfun->stmt->x_block_stack)
376 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
377 #define cond_stack (cfun->stmt->x_cond_stack)
378 #define loop_stack (cfun->stmt->x_loop_stack)
379 #define case_stack (cfun->stmt->x_case_stack)
380 #define nesting_stack (cfun->stmt->x_nesting_stack)
381 #define nesting_depth (cfun->stmt->x_nesting_depth)
382 #define current_block_start_count (cfun->stmt->x_block_start_count)
383 #define last_expr_type (cfun->stmt->x_last_expr_type)
384 #define last_expr_value (cfun->stmt->x_last_expr_value)
385 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
386 #define emit_locus (cfun->stmt->x_emit_locus)
387 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
389 /* Nonzero if we are using EH to handle cleanups. */
390 static int using_eh_for_cleanups_p = 0;
392 static int n_occurrences (int, const char *);
393 static bool parse_input_constraint (const char **, int, int, int, int,
394 const char * const *, bool *, bool *);
395 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
396 static void expand_goto_internal (tree, rtx, rtx);
397 static int expand_fixup (tree, rtx, rtx);
398 static rtx expand_nl_handler_label (rtx, rtx);
399 static void expand_nl_goto_receiver (void);
400 static void expand_nl_goto_receivers (struct nesting *);
401 static void fixup_gotos (struct nesting *, rtx, tree, rtx, int);
402 static bool check_operand_nalternatives (tree, tree);
403 static bool check_unique_operand_names (tree, tree);
404 static char *resolve_operand_name_1 (char *, tree, tree);
405 static void expand_null_return_1 (rtx);
406 static enum br_predictor return_prediction (rtx);
407 static void expand_value_return (rtx);
408 static int tail_recursion_args (tree, tree);
409 static void expand_cleanups (tree, int, int);
410 static void check_seenlabel (void);
411 static void do_jump_if_equal (rtx, rtx, rtx, int);
412 static int estimate_case_costs (case_node_ptr);
413 static bool same_case_target_p (rtx, rtx);
414 static void strip_default_case_nodes (case_node_ptr *, rtx);
415 static bool lshift_cheap_p (void);
416 static int case_bit_test_cmp (const void *, const void *);
417 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
418 static void group_case_nodes (case_node_ptr);
419 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
420 static int node_has_low_bound (case_node_ptr, tree);
421 static int node_has_high_bound (case_node_ptr, tree);
422 static int node_is_bounded (case_node_ptr, tree);
423 static void emit_jump_if_reachable (rtx);
424 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
425 static struct case_node *case_tree2list (case_node *, case_node *);
428 using_eh_for_cleanups (void)
430 using_eh_for_cleanups_p = 1;
434 init_stmt_for_function (void)
436 cfun->stmt = ggc_alloc_cleared (sizeof (struct stmt_status));
439 /* Record the current file and line. Called from emit_line_note. */
442 set_file_and_line_for_stmt (location_t location)
444 /* If we're outputting an inline function, and we add a line note,
445 there may be no CFUN->STMT information. So, there's no need to
448 emit_locus = location;
451 /* Emit a no-op instruction. */
458 last_insn = get_last_insn ();
460 && (GET_CODE (last_insn) == CODE_LABEL
461 || (GET_CODE (last_insn) == NOTE
462 && prev_real_insn (last_insn) == 0)))
463 emit_insn (gen_nop ());
466 /* Return the rtx-label that corresponds to a LABEL_DECL,
467 creating it if necessary. */
470 label_rtx (tree label)
472 if (TREE_CODE (label) != LABEL_DECL)
475 if (!DECL_RTL_SET_P (label))
476 SET_DECL_RTL (label, gen_label_rtx ());
478 return DECL_RTL (label);
481 /* As above, but also put it on the forced-reference list of the
482 function that contains it. */
484 force_label_rtx (tree label)
486 rtx ref = label_rtx (label);
487 tree function = decl_function_context (label);
493 if (function != current_function_decl
494 && function != inline_function_decl)
495 p = find_function_data (function);
499 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
500 p->expr->x_forced_labels);
504 /* Add an unconditional jump to LABEL as the next sequential instruction. */
507 emit_jump (rtx label)
509 do_pending_stack_adjust ();
510 emit_jump_insn (gen_jump (label));
514 /* Emit code to jump to the address
515 specified by the pointer expression EXP. */
518 expand_computed_goto (tree exp)
520 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
522 #ifdef POINTERS_EXTEND_UNSIGNED
523 if (GET_MODE (x) != Pmode)
524 x = convert_memory_address (Pmode, x);
529 if (! cfun->computed_goto_common_label)
531 cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
532 cfun->computed_goto_common_label = gen_label_rtx ();
533 emit_label (cfun->computed_goto_common_label);
535 do_pending_stack_adjust ();
536 emit_indirect_jump (cfun->computed_goto_common_reg);
538 current_function_has_computed_jump = 1;
542 emit_move_insn (cfun->computed_goto_common_reg, x);
543 emit_jump (cfun->computed_goto_common_label);
547 /* Handle goto statements and the labels that they can go to. */
549 /* Specify the location in the RTL code of a label LABEL,
550 which is a LABEL_DECL tree node.
552 This is used for the kind of label that the user can jump to with a
553 goto statement, and for alternatives of a switch or case statement.
554 RTL labels generated for loops and conditionals don't go through here;
555 they are generated directly at the RTL level, by other functions below.
557 Note that this has nothing to do with defining label *names*.
558 Languages vary in how they do that and what that even means. */
561 expand_label (tree label)
563 struct label_chain *p;
565 do_pending_stack_adjust ();
566 emit_label (label_rtx (label));
567 if (DECL_NAME (label))
568 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
570 if (stack_block_stack != 0)
572 p = ggc_alloc (sizeof (struct label_chain));
573 p->next = stack_block_stack->data.block.label_chain;
574 stack_block_stack->data.block.label_chain = p;
579 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
580 from nested functions. */
583 declare_nonlocal_label (tree label)
585 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
587 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
588 LABEL_PRESERVE_P (label_rtx (label)) = 1;
589 if (nonlocal_goto_handler_slots == 0)
591 emit_stack_save (SAVE_NONLOCAL,
592 &nonlocal_goto_stack_level,
593 PREV_INSN (tail_recursion_reentry));
595 nonlocal_goto_handler_slots
596 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
599 /* Generate RTL code for a `goto' statement with target label LABEL.
600 LABEL should be a LABEL_DECL tree node that was or will later be
601 defined with `expand_label'. */
604 expand_goto (tree label)
608 /* Check for a nonlocal goto to a containing function. */
609 context = decl_function_context (label);
610 if (context != 0 && context != current_function_decl)
612 struct function *p = find_function_data (context);
613 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
614 rtx handler_slot, static_chain, save_area, insn;
617 /* Find the corresponding handler slot for this label. */
618 handler_slot = p->x_nonlocal_goto_handler_slots;
619 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
620 link = TREE_CHAIN (link))
621 handler_slot = XEXP (handler_slot, 1);
622 handler_slot = XEXP (handler_slot, 0);
624 p->has_nonlocal_label = 1;
625 current_function_has_nonlocal_goto = 1;
626 LABEL_REF_NONLOCAL_P (label_ref) = 1;
628 /* Copy the rtl for the slots so that they won't be shared in
629 case the virtual stack vars register gets instantiated differently
630 in the parent than in the child. */
632 static_chain = copy_to_reg (lookup_static_chain (label));
634 /* Get addr of containing function's current nonlocal goto handler,
635 which will do any cleanups and then jump to the label. */
636 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
637 virtual_stack_vars_rtx,
640 /* Get addr of containing function's nonlocal save area. */
641 save_area = p->x_nonlocal_goto_stack_level;
643 save_area = replace_rtx (copy_rtx (save_area),
644 virtual_stack_vars_rtx, static_chain);
646 #if HAVE_nonlocal_goto
647 if (HAVE_nonlocal_goto)
648 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
649 save_area, label_ref));
653 /* Restore frame pointer for containing function.
654 This sets the actual hard register used for the frame pointer
655 to the location of the function's incoming static chain info.
656 The non-local goto handler will then adjust it to contain the
657 proper value and reload the argument pointer, if needed. */
658 emit_move_insn (hard_frame_pointer_rtx, static_chain);
659 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
661 /* USE of hard_frame_pointer_rtx added for consistency;
662 not clear if really needed. */
663 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
664 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
665 emit_indirect_jump (handler_slot);
668 /* Search backwards to the jump insn and mark it as a
670 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
672 if (GET_CODE (insn) == JUMP_INSN)
674 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
675 const0_rtx, REG_NOTES (insn));
678 else if (GET_CODE (insn) == CALL_INSN)
683 expand_goto_internal (label, label_rtx (label), NULL_RTX);
686 /* Generate RTL code for a `goto' statement with target label BODY.
687 LABEL should be a LABEL_REF.
688 LAST_INSN, if non-0, is the rtx we should consider as the last
689 insn emitted (for the purposes of cleaning up a return). */
692 expand_goto_internal (tree body, rtx label, rtx last_insn)
694 struct nesting *block;
697 if (GET_CODE (label) != CODE_LABEL)
700 /* If label has already been defined, we can tell now
701 whether and how we must alter the stack level. */
703 if (PREV_INSN (label) != 0)
705 /* Find the innermost pending block that contains the label.
706 (Check containment by comparing insn-uids.)
707 Then restore the outermost stack level within that block,
708 and do cleanups of all blocks contained in it. */
709 for (block = block_stack; block; block = block->next)
711 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
713 if (block->data.block.stack_level != 0)
714 stack_level = block->data.block.stack_level;
715 /* Execute the cleanups for blocks we are exiting. */
716 if (block->data.block.cleanups != 0)
718 expand_cleanups (block->data.block.cleanups, 1, 1);
719 do_pending_stack_adjust ();
725 /* Ensure stack adjust isn't done by emit_jump, as this
726 would clobber the stack pointer. This one should be
727 deleted as dead by flow. */
728 clear_pending_stack_adjust ();
729 do_pending_stack_adjust ();
731 /* Don't do this adjust if it's to the end label and this function
732 is to return with a depressed stack pointer. */
733 if (label == return_label
734 && (((TREE_CODE (TREE_TYPE (current_function_decl))
736 && (TYPE_RETURNS_STACK_DEPRESSED
737 (TREE_TYPE (current_function_decl))))))
740 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
743 if (body != 0 && DECL_TOO_LATE (body))
744 error ("jump to `%s' invalidly jumps into binding contour",
745 IDENTIFIER_POINTER (DECL_NAME (body)));
747 /* Label not yet defined: may need to put this goto
748 on the fixup list. */
749 else if (! expand_fixup (body, label, last_insn))
751 /* No fixup needed. Record that the label is the target
752 of at least one goto that has no fixup. */
754 TREE_ADDRESSABLE (body) = 1;
760 /* Generate if necessary a fixup for a goto
761 whose target label in tree structure (if any) is TREE_LABEL
762 and whose target in rtl is RTL_LABEL.
764 If LAST_INSN is nonzero, we pretend that the jump appears
765 after insn LAST_INSN instead of at the current point in the insn stream.
767 The fixup will be used later to insert insns just before the goto.
768 Those insns will restore the stack level as appropriate for the
769 target label, and will (in the case of C++) also invoke any object
770 destructors which have to be invoked when we exit the scopes which
771 are exited by the goto.
773 Value is nonzero if a fixup is made. */
776 expand_fixup (tree tree_label, rtx rtl_label, rtx last_insn)
778 struct nesting *block, *end_block;
780 /* See if we can recognize which block the label will be output in.
781 This is possible in some very common cases.
782 If we succeed, set END_BLOCK to that block.
783 Otherwise, set it to 0. */
786 && (rtl_label == cond_stack->data.cond.endif_label
787 || rtl_label == cond_stack->data.cond.next_label))
788 end_block = cond_stack;
789 /* If we are in a loop, recognize certain labels which
790 are likely targets. This reduces the number of fixups
791 we need to create. */
793 && (rtl_label == loop_stack->data.loop.start_label
794 || rtl_label == loop_stack->data.loop.end_label
795 || rtl_label == loop_stack->data.loop.continue_label))
796 end_block = loop_stack;
800 /* Now set END_BLOCK to the binding level to which we will return. */
804 struct nesting *next_block = end_block->all;
807 /* First see if the END_BLOCK is inside the innermost binding level.
808 If so, then no cleanups or stack levels are relevant. */
809 while (next_block && next_block != block)
810 next_block = next_block->all;
815 /* Otherwise, set END_BLOCK to the innermost binding level
816 which is outside the relevant control-structure nesting. */
817 next_block = block_stack->next;
818 for (block = block_stack; block != end_block; block = block->all)
819 if (block == next_block)
820 next_block = next_block->next;
821 end_block = next_block;
824 /* Does any containing block have a stack level or cleanups?
825 If not, no fixup is needed, and that is the normal case
826 (the only case, for standard C). */
827 for (block = block_stack; block != end_block; block = block->next)
828 if (block->data.block.stack_level != 0
829 || block->data.block.cleanups != 0)
832 if (block != end_block)
834 /* Ok, a fixup is needed. Add a fixup to the list of such. */
835 struct goto_fixup *fixup = ggc_alloc (sizeof (struct goto_fixup));
836 /* In case an old stack level is restored, make sure that comes
837 after any pending stack adjust. */
838 /* ?? If the fixup isn't to come at the present position,
839 doing the stack adjust here isn't useful. Doing it with our
840 settings at that location isn't useful either. Let's hope
843 do_pending_stack_adjust ();
844 fixup->target = tree_label;
845 fixup->target_rtl = rtl_label;
847 /* Create a BLOCK node and a corresponding matched set of
848 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
849 this point. The notes will encapsulate any and all fixup
850 code which we might later insert at this point in the insn
851 stream. Also, the BLOCK node will be the parent (i.e. the
852 `SUPERBLOCK') of any other BLOCK nodes which we might create
853 later on when we are expanding the fixup code.
855 Note that optimization passes (including expand_end_loop)
856 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
860 rtx original_before_jump
861 = last_insn ? last_insn : get_last_insn ();
866 block = make_node (BLOCK);
867 TREE_USED (block) = 1;
869 if (!cfun->x_whole_function_mode_p)
870 (*lang_hooks.decls.insert_block) (block);
874 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
875 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
880 start = emit_note (NOTE_INSN_BLOCK_BEG);
881 if (cfun->x_whole_function_mode_p)
882 NOTE_BLOCK (start) = block;
883 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
884 end = emit_note (NOTE_INSN_BLOCK_END);
885 if (cfun->x_whole_function_mode_p)
886 NOTE_BLOCK (end) = block;
887 fixup->context = block;
889 emit_insn_after (start, original_before_jump);
892 fixup->block_start_count = current_block_start_count;
893 fixup->stack_level = 0;
894 fixup->cleanup_list_list
895 = ((block->data.block.outer_cleanups
896 || block->data.block.cleanups)
897 ? tree_cons (NULL_TREE, block->data.block.cleanups,
898 block->data.block.outer_cleanups)
900 fixup->next = goto_fixup_chain;
901 goto_fixup_chain = fixup;
907 /* Expand any needed fixups in the outputmost binding level of the
908 function. FIRST_INSN is the first insn in the function. */
911 expand_fixups (rtx first_insn)
913 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
916 /* When exiting a binding contour, process all pending gotos requiring fixups.
917 THISBLOCK is the structure that describes the block being exited.
918 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
919 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
920 FIRST_INSN is the insn that began this contour.
922 Gotos that jump out of this contour must restore the
923 stack level and do the cleanups before actually jumping.
925 DONT_JUMP_IN positive means report error if there is a jump into this
926 contour from before the beginning of the contour. This is also done if
927 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
930 fixup_gotos (struct nesting *thisblock, rtx stack_level,
931 tree cleanup_list, rtx first_insn, int dont_jump_in)
933 struct goto_fixup *f, *prev;
935 /* F is the fixup we are considering; PREV is the previous one. */
936 /* We run this loop in two passes so that cleanups of exited blocks
937 are run first, and blocks that are exited are marked so
940 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
942 /* Test for a fixup that is inactive because it is already handled. */
943 if (f->before_jump == 0)
945 /* Delete inactive fixup from the chain, if that is easy to do. */
947 prev->next = f->next;
949 /* Has this fixup's target label been defined?
950 If so, we can finalize it. */
951 else if (PREV_INSN (f->target_rtl) != 0)
955 /* If this fixup jumped into this contour from before the beginning
956 of this contour, report an error. This code used to use
957 the first non-label insn after f->target_rtl, but that's
958 wrong since such can be added, by things like put_var_into_stack
959 and have INSN_UIDs that are out of the range of the block. */
960 /* ??? Bug: this does not detect jumping in through intermediate
961 blocks that have stack levels or cleanups.
962 It detects only a problem with the innermost block
965 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
967 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
968 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
969 && ! DECL_ERROR_ISSUED (f->target))
971 error ("%Hlabel '%D' used before containing binding contour",
972 &DECL_SOURCE_LOCATION (f->target), f->target);
973 /* Prevent multiple errors for one label. */
974 DECL_ERROR_ISSUED (f->target) = 1;
977 /* We will expand the cleanups into a sequence of their own and
978 then later on we will attach this new sequence to the insn
979 stream just ahead of the actual jump insn. */
983 /* Temporarily restore the lexical context where we will
984 logically be inserting the fixup code. We do this for the
985 sake of getting the debugging information right. */
987 (*lang_hooks.decls.pushlevel) (0);
988 (*lang_hooks.decls.set_block) (f->context);
990 /* Expand the cleanups for blocks this jump exits. */
991 if (f->cleanup_list_list)
994 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
995 /* Marked elements correspond to blocks that have been closed.
996 Do their cleanups. */
997 if (TREE_ADDRESSABLE (lists)
998 && TREE_VALUE (lists) != 0)
1000 expand_cleanups (TREE_VALUE (lists), 1, 1);
1001 /* Pop any pushes done in the cleanups,
1002 in case function is about to return. */
1003 do_pending_stack_adjust ();
1007 /* Restore stack level for the biggest contour that this
1008 jump jumps out of. */
1010 && ! (f->target_rtl == return_label
1011 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1013 && (TYPE_RETURNS_STACK_DEPRESSED
1014 (TREE_TYPE (current_function_decl))))))
1015 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1017 /* Finish up the sequence containing the insns which implement the
1018 necessary cleanups, and then attach that whole sequence to the
1019 insn stream just ahead of the actual jump insn. Attaching it
1020 at that point insures that any cleanups which are in fact
1021 implicit C++ object destructions (which must be executed upon
1022 leaving the block) appear (to the debugger) to be taking place
1023 in an area of the generated code where the object(s) being
1024 destructed are still "in scope". */
1026 cleanup_insns = get_insns ();
1027 (*lang_hooks.decls.poplevel) (1, 0, 0);
1030 emit_insn_after (cleanup_insns, f->before_jump);
1036 /* For any still-undefined labels, do the cleanups for this block now.
1037 We must do this now since items in the cleanup list may go out
1038 of scope when the block ends. */
1039 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1040 if (f->before_jump != 0
1041 && PREV_INSN (f->target_rtl) == 0
1042 /* Label has still not appeared. If we are exiting a block with
1043 a stack level to restore, that started before the fixup,
1044 mark this stack level as needing restoration
1045 when the fixup is later finalized. */
1047 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1048 means the label is undefined. That's erroneous, but possible. */
1049 && (thisblock->data.block.block_start_count
1050 <= f->block_start_count))
1052 tree lists = f->cleanup_list_list;
1055 for (; lists; lists = TREE_CHAIN (lists))
1056 /* If the following elt. corresponds to our containing block
1057 then the elt. must be for this block. */
1058 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1061 (*lang_hooks.decls.pushlevel) (0);
1062 (*lang_hooks.decls.set_block) (f->context);
1063 expand_cleanups (TREE_VALUE (lists), 1, 1);
1064 do_pending_stack_adjust ();
1065 cleanup_insns = get_insns ();
1066 (*lang_hooks.decls.poplevel) (1, 0, 0);
1068 if (cleanup_insns != 0)
1070 = emit_insn_after (cleanup_insns, f->before_jump);
1072 f->cleanup_list_list = TREE_CHAIN (lists);
1076 f->stack_level = stack_level;
1080 /* Return the number of times character C occurs in string S. */
1082 n_occurrences (int c, const char *s)
1090 /* Generate RTL for an asm statement (explicit assembler code).
1091 STRING is a STRING_CST node containing the assembler code text,
1092 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
1093 insn is volatile; don't optimize it. */
1096 expand_asm (tree string, int vol)
1100 if (TREE_CODE (string) == ADDR_EXPR)
1101 string = TREE_OPERAND (string, 0);
1103 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
1105 MEM_VOLATILE_P (body) = vol;
1112 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1113 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1114 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1115 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1116 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1117 constraint allows the use of a register operand. And, *IS_INOUT
1118 will be true if the operand is read-write, i.e., if it is used as
1119 an input as well as an output. If *CONSTRAINT_P is not in
1120 canonical form, it will be made canonical. (Note that `+' will be
1121 replaced with `=' as part of this process.)
1123 Returns TRUE if all went well; FALSE if an error occurred. */
1126 parse_output_constraint (const char **constraint_p, int operand_num,
1127 int ninputs, int noutputs, bool *allows_mem,
1128 bool *allows_reg, bool *is_inout)
1130 const char *constraint = *constraint_p;
1133 /* Assume the constraint doesn't allow the use of either a register
1135 *allows_mem = false;
1136 *allows_reg = false;
1138 /* Allow the `=' or `+' to not be at the beginning of the string,
1139 since it wasn't explicitly documented that way, and there is a
1140 large body of code that puts it last. Swap the character to
1141 the front, so as not to uglify any place else. */
1142 p = strchr (constraint, '=');
1144 p = strchr (constraint, '+');
1146 /* If the string doesn't contain an `=', issue an error
1150 error ("output operand constraint lacks `='");
1154 /* If the constraint begins with `+', then the operand is both read
1155 from and written to. */
1156 *is_inout = (*p == '+');
1158 /* Canonicalize the output constraint so that it begins with `='. */
1159 if (p != constraint || is_inout)
1162 size_t c_len = strlen (constraint);
1164 if (p != constraint)
1165 warning ("output constraint `%c' for operand %d is not at the beginning",
1168 /* Make a copy of the constraint. */
1169 buf = alloca (c_len + 1);
1170 strcpy (buf, constraint);
1171 /* Swap the first character and the `=' or `+'. */
1172 buf[p - constraint] = buf[0];
1173 /* Make sure the first character is an `='. (Until we do this,
1174 it might be a `+'.) */
1176 /* Replace the constraint with the canonicalized string. */
1177 *constraint_p = ggc_alloc_string (buf, c_len);
1178 constraint = *constraint_p;
1181 /* Loop through the constraint string. */
1182 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1187 error ("operand constraint contains incorrectly positioned '+' or '='");
1191 if (operand_num + 1 == ninputs + noutputs)
1193 error ("`%%' constraint used with last operand");
1198 case 'V': case 'm': case 'o':
1202 case '?': case '!': case '*': case '&': case '#':
1203 case 'E': case 'F': case 'G': case 'H':
1204 case 's': case 'i': case 'n':
1205 case 'I': case 'J': case 'K': case 'L': case 'M':
1206 case 'N': case 'O': case 'P': case ',':
1209 case '0': case '1': case '2': case '3': case '4':
1210 case '5': case '6': case '7': case '8': case '9':
1212 error ("matching constraint not valid in output operand");
1216 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1217 excepting those that expand_call created. So match memory
1234 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1236 #ifdef EXTRA_CONSTRAINT_STR
1237 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1239 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1243 /* Otherwise we can't assume anything about the nature of
1244 the constraint except that it isn't purely registers.
1245 Treat it like "g" and hope for the best. */
1256 /* Similar, but for input constraints. */
1259 parse_input_constraint (const char **constraint_p, int input_num,
1260 int ninputs, int noutputs, int ninout,
1261 const char * const * constraints,
1262 bool *allows_mem, bool *allows_reg)
1264 const char *constraint = *constraint_p;
1265 const char *orig_constraint = constraint;
1266 size_t c_len = strlen (constraint);
1269 /* Assume the constraint doesn't allow the use of either
1270 a register or memory. */
1271 *allows_mem = false;
1272 *allows_reg = false;
1274 /* Make sure constraint has neither `=', `+', nor '&'. */
1276 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1277 switch (constraint[j])
1279 case '+': case '=': case '&':
1280 if (constraint == orig_constraint)
1282 error ("input operand constraint contains `%c'", constraint[j]);
1288 if (constraint == orig_constraint
1289 && input_num + 1 == ninputs - ninout)
1291 error ("`%%' constraint used with last operand");
1296 case 'V': case 'm': case 'o':
1301 case '?': case '!': case '*': case '#':
1302 case 'E': case 'F': case 'G': case 'H':
1303 case 's': case 'i': case 'n':
1304 case 'I': case 'J': case 'K': case 'L': case 'M':
1305 case 'N': case 'O': case 'P': case ',':
1308 /* Whether or not a numeric constraint allows a register is
1309 decided by the matching constraint, and so there is no need
1310 to do anything special with them. We must handle them in
1311 the default case, so that we don't unnecessarily force
1312 operands to memory. */
1313 case '0': case '1': case '2': case '3': case '4':
1314 case '5': case '6': case '7': case '8': case '9':
1317 unsigned long match;
1319 match = strtoul (constraint + j, &end, 10);
1320 if (match >= (unsigned long) noutputs)
1322 error ("matching constraint references invalid operand number");
1326 /* Try and find the real constraint for this dup. Only do this
1327 if the matching constraint is the only alternative. */
1329 && (j == 0 || (j == 1 && constraint[0] == '%')))
1331 constraint = constraints[match];
1332 *constraint_p = constraint;
1333 c_len = strlen (constraint);
1335 /* ??? At the end of the loop, we will skip the first part of
1336 the matched constraint. This assumes not only that the
1337 other constraint is an output constraint, but also that
1338 the '=' or '+' come first. */
1342 j = end - constraint;
1343 /* Anticipate increment at end of loop. */
1358 if (! ISALPHA (constraint[j]))
1360 error ("invalid punctuation `%c' in constraint", constraint[j]);
1363 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1366 #ifdef EXTRA_CONSTRAINT_STR
1367 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1369 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1373 /* Otherwise we can't assume anything about the nature of
1374 the constraint except that it isn't purely registers.
1375 Treat it like "g" and hope for the best. */
1386 /* Check for overlap between registers marked in CLOBBERED_REGS and
1387 anything inappropriate in DECL. Emit error and return TRUE for error,
1391 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
1393 /* Conflicts between asm-declared register variables and the clobber
1394 list are not allowed. */
1395 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1396 && DECL_REGISTER (decl)
1397 && REG_P (DECL_RTL (decl))
1398 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1400 rtx reg = DECL_RTL (decl);
1403 for (regno = REGNO (reg);
1404 regno < (REGNO (reg)
1405 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1407 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1409 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1410 IDENTIFIER_POINTER (DECL_NAME (decl)));
1412 /* Reset registerness to stop multiple errors emitted for a
1414 DECL_REGISTER (decl) = 0;
1421 /* Generate RTL for an asm statement with arguments.
1422 STRING is the instruction template.
1423 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1424 Each output or input has an expression in the TREE_VALUE and
1425 and a tree list in TREE_PURPOSE which in turn contains a constraint
1426 name in TREE_VALUE (or NULL_TREE) and a constraint string
1428 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1429 that is clobbered by this insn.
1431 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1432 Some elements of OUTPUTS may be replaced with trees representing temporary
1433 values. The caller should copy those temporary values to the originally
1436 VOL nonzero means the insn is volatile; don't optimize it. */
1439 expand_asm_operands (tree string, tree outputs, tree inputs,
1440 tree clobbers, int vol, const char *filename, int line)
1442 rtvec argvec, constraintvec;
1444 int ninputs = list_length (inputs);
1445 int noutputs = list_length (outputs);
1448 HARD_REG_SET clobbered_regs;
1449 int clobber_conflict_found = 0;
1453 /* Vector of RTX's of evaluated output operands. */
1454 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
1455 int *inout_opnum = alloca (noutputs * sizeof (int));
1456 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
1457 enum machine_mode *inout_mode
1458 = alloca (noutputs * sizeof (enum machine_mode));
1459 const char **constraints
1460 = alloca ((noutputs + ninputs) * sizeof (const char *));
1461 int old_generating_concat_p = generating_concat_p;
1463 /* An ASM with no outputs needs to be treated as volatile, for now. */
1467 if (! check_operand_nalternatives (outputs, inputs))
1470 if (! check_unique_operand_names (outputs, inputs))
1473 string = resolve_asm_operand_names (string, outputs, inputs);
1475 /* Collect constraints. */
1477 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1478 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1479 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1480 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1482 #ifdef MD_ASM_CLOBBERS
1483 /* Sometimes we wish to automatically clobber registers across an asm.
1484 Case in point is when the i386 backend moved from cc0 to a hard reg --
1485 maintaining source-level compatibility means automatically clobbering
1486 the flags register. */
1487 MD_ASM_CLOBBERS (clobbers);
1490 /* Count the number of meaningful clobbered registers, ignoring what
1491 we would ignore later. */
1493 CLEAR_HARD_REG_SET (clobbered_regs);
1494 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1496 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1498 i = decode_reg_name (regname);
1499 if (i >= 0 || i == -4)
1502 error ("unknown register name `%s' in `asm'", regname);
1504 /* Mark clobbered registers. */
1507 /* Clobbering the PIC register is an error */
1508 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1510 error ("PIC register `%s' clobbered in `asm'", regname);
1514 SET_HARD_REG_BIT (clobbered_regs, i);
1520 /* First pass over inputs and outputs checks validity and sets
1521 mark_addressable if needed. */
1524 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1526 tree val = TREE_VALUE (tail);
1527 tree type = TREE_TYPE (val);
1528 const char *constraint;
1533 /* If there's an erroneous arg, emit no insn. */
1534 if (type == error_mark_node)
1537 /* Try to parse the output constraint. If that fails, there's
1538 no point in going further. */
1539 constraint = constraints[i];
1540 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1541 &allows_mem, &allows_reg, &is_inout))
1548 && GET_CODE (DECL_RTL (val)) == REG
1549 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1550 (*lang_hooks.mark_addressable) (val);
1557 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1559 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1563 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1565 bool allows_reg, allows_mem;
1566 const char *constraint;
1568 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1569 would get VOIDmode and that could cause a crash in reload. */
1570 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1573 constraint = constraints[i + noutputs];
1574 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1575 constraints, &allows_mem, &allows_reg))
1578 if (! allows_reg && allows_mem)
1579 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1582 /* Second pass evaluates arguments. */
1585 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1587 tree val = TREE_VALUE (tail);
1588 tree type = TREE_TYPE (val);
1594 if (!parse_output_constraint (&constraints[i], i, ninputs,
1595 noutputs, &allows_mem, &allows_reg,
1599 /* If an output operand is not a decl or indirect ref and our constraint
1600 allows a register, make a temporary to act as an intermediate.
1601 Make the asm insn write into that, then our caller will copy it to
1602 the real output operand. Likewise for promoted variables. */
1604 generating_concat_p = 0;
1606 real_output_rtx[i] = NULL_RTX;
1607 if ((TREE_CODE (val) == INDIRECT_REF
1610 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1611 && ! (GET_CODE (DECL_RTL (val)) == REG
1612 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1616 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1617 if (GET_CODE (op) == MEM)
1618 op = validize_mem (op);
1620 if (! allows_reg && GET_CODE (op) != MEM)
1621 error ("output number %d not directly addressable", i);
1622 if ((! allows_mem && GET_CODE (op) == MEM)
1623 || GET_CODE (op) == CONCAT)
1625 real_output_rtx[i] = protect_from_queue (op, 1);
1626 op = gen_reg_rtx (GET_MODE (op));
1628 emit_move_insn (op, real_output_rtx[i]);
1633 op = assign_temp (type, 0, 0, 1);
1634 op = validize_mem (op);
1635 TREE_VALUE (tail) = make_tree (type, op);
1639 generating_concat_p = old_generating_concat_p;
1643 inout_mode[ninout] = TYPE_MODE (type);
1644 inout_opnum[ninout++] = i;
1647 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1648 clobber_conflict_found = 1;
1651 /* Make vectors for the expression-rtx, constraint strings,
1652 and named operands. */
1654 argvec = rtvec_alloc (ninputs);
1655 constraintvec = rtvec_alloc (ninputs);
1657 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1658 : GET_MODE (output_rtx[0])),
1659 TREE_STRING_POINTER (string),
1660 empty_string, 0, argvec, constraintvec,
1663 MEM_VOLATILE_P (body) = vol;
1665 /* Eval the inputs and put them into ARGVEC.
1666 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1668 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1670 bool allows_reg, allows_mem;
1671 const char *constraint;
1675 constraint = constraints[i + noutputs];
1676 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1677 constraints, &allows_mem, &allows_reg))
1680 generating_concat_p = 0;
1682 val = TREE_VALUE (tail);
1683 type = TREE_TYPE (val);
1684 op = expand_expr (val, NULL_RTX, VOIDmode,
1685 (allows_mem && !allows_reg
1686 ? EXPAND_MEMORY : EXPAND_NORMAL));
1688 /* Never pass a CONCAT to an ASM. */
1689 if (GET_CODE (op) == CONCAT)
1690 op = force_reg (GET_MODE (op), op);
1691 else if (GET_CODE (op) == MEM)
1692 op = validize_mem (op);
1694 if (asm_operand_ok (op, constraint) <= 0)
1697 op = force_reg (TYPE_MODE (type), op);
1698 else if (!allows_mem)
1699 warning ("asm operand %d probably doesn't match constraints",
1701 else if (GET_CODE (op) == MEM)
1703 /* We won't recognize either volatile memory or memory
1704 with a queued address as available a memory_operand
1705 at this point. Ignore it: clearly this *is* a memory. */
1709 warning ("use of memory input without lvalue in "
1710 "asm operand %d is deprecated", i + noutputs);
1712 if (CONSTANT_P (op))
1714 op = force_const_mem (TYPE_MODE (type), op);
1715 op = validize_mem (op);
1717 else if (GET_CODE (op) == REG
1718 || GET_CODE (op) == SUBREG
1719 || GET_CODE (op) == ADDRESSOF
1720 || GET_CODE (op) == CONCAT)
1722 tree qual_type = build_qualified_type (type,
1724 | TYPE_QUAL_CONST));
1725 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1726 memloc = validize_mem (memloc);
1727 emit_move_insn (memloc, op);
1733 generating_concat_p = old_generating_concat_p;
1734 ASM_OPERANDS_INPUT (body, i) = op;
1736 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1737 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1739 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1740 clobber_conflict_found = 1;
1743 /* Protect all the operands from the queue now that they have all been
1746 generating_concat_p = 0;
1748 for (i = 0; i < ninputs - ninout; i++)
1749 ASM_OPERANDS_INPUT (body, i)
1750 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1752 for (i = 0; i < noutputs; i++)
1753 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1755 /* For in-out operands, copy output rtx to input rtx. */
1756 for (i = 0; i < ninout; i++)
1758 int j = inout_opnum[i];
1761 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1764 sprintf (buffer, "%d", j);
1765 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1766 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
1769 generating_concat_p = old_generating_concat_p;
1771 /* Now, for each output, construct an rtx
1772 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1773 ARGVEC CONSTRAINTS OPNAMES))
1774 If there is more than one, put them inside a PARALLEL. */
1776 if (noutputs == 1 && nclobbers == 0)
1778 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1779 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1782 else if (noutputs == 0 && nclobbers == 0)
1784 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1796 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1798 /* For each output operand, store a SET. */
1799 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1801 XVECEXP (body, 0, i)
1802 = gen_rtx_SET (VOIDmode,
1804 gen_rtx_ASM_OPERANDS
1805 (GET_MODE (output_rtx[i]),
1806 TREE_STRING_POINTER (string),
1807 constraints[i], i, argvec, constraintvec,
1810 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1813 /* If there are no outputs (but there are some clobbers)
1814 store the bare ASM_OPERANDS into the PARALLEL. */
1817 XVECEXP (body, 0, i++) = obody;
1819 /* Store (clobber REG) for each clobbered register specified. */
1821 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1823 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1824 int j = decode_reg_name (regname);
1829 if (j == -3) /* `cc', which is not a register */
1832 if (j == -4) /* `memory', don't cache memory across asm */
1834 XVECEXP (body, 0, i++)
1835 = gen_rtx_CLOBBER (VOIDmode,
1838 gen_rtx_SCRATCH (VOIDmode)));
1842 /* Ignore unknown register, error already signaled. */
1846 /* Use QImode since that's guaranteed to clobber just one reg. */
1847 clobbered_reg = gen_rtx_REG (QImode, j);
1849 /* Do sanity check for overlap between clobbers and respectively
1850 input and outputs that hasn't been handled. Such overlap
1851 should have been detected and reported above. */
1852 if (!clobber_conflict_found)
1856 /* We test the old body (obody) contents to avoid tripping
1857 over the under-construction body. */
1858 for (opno = 0; opno < noutputs; opno++)
1859 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1860 internal_error ("asm clobber conflict with output operand");
1862 for (opno = 0; opno < ninputs - ninout; opno++)
1863 if (reg_overlap_mentioned_p (clobbered_reg,
1864 ASM_OPERANDS_INPUT (obody, opno)))
1865 internal_error ("asm clobber conflict with input operand");
1868 XVECEXP (body, 0, i++)
1869 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1875 /* For any outputs that needed reloading into registers, spill them
1876 back to where they belong. */
1877 for (i = 0; i < noutputs; ++i)
1878 if (real_output_rtx[i])
1879 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1884 /* A subroutine of expand_asm_operands. Check that all operands have
1885 the same number of alternatives. Return true if so. */
1888 check_operand_nalternatives (tree outputs, tree inputs)
1890 if (outputs || inputs)
1892 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1894 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1897 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1899 error ("too many alternatives in `asm'");
1906 const char *constraint
1907 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1909 if (n_occurrences (',', constraint) != nalternatives)
1911 error ("operand constraints for `asm' differ in number of alternatives");
1915 if (TREE_CHAIN (tmp))
1916 tmp = TREE_CHAIN (tmp);
1918 tmp = next, next = 0;
1925 /* A subroutine of expand_asm_operands. Check that all operand names
1926 are unique. Return true if so. We rely on the fact that these names
1927 are identifiers, and so have been canonicalized by get_identifier,
1928 so all we need are pointer comparisons. */
1931 check_unique_operand_names (tree outputs, tree inputs)
1935 for (i = outputs; i ; i = TREE_CHAIN (i))
1937 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1941 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1942 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1946 for (i = inputs; i ; i = TREE_CHAIN (i))
1948 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1952 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1953 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1955 for (j = outputs; j ; j = TREE_CHAIN (j))
1956 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1963 error ("duplicate asm operand name '%s'",
1964 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1968 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1969 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1970 STRING and in the constraints to those numbers. */
1973 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1980 /* Substitute [<name>] in input constraint strings. There should be no
1981 named operands in output constraints. */
1982 for (t = inputs; t ; t = TREE_CHAIN (t))
1984 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1985 if (strchr (c, '[') != NULL)
1987 p = buffer = xstrdup (c);
1988 while ((p = strchr (p, '[')) != NULL)
1989 p = resolve_operand_name_1 (p, outputs, inputs);
1990 TREE_VALUE (TREE_PURPOSE (t))
1991 = build_string (strlen (buffer), buffer);
1996 /* Now check for any needed substitutions in the template. */
1997 c = TREE_STRING_POINTER (string);
1998 while ((c = strchr (c, '%')) != NULL)
2002 else if (ISALPHA (c[1]) && c[2] == '[')
2013 /* OK, we need to make a copy so we can perform the substitutions.
2014 Assume that we will not need extra space--we get to remove '['
2015 and ']', which means we cannot have a problem until we have more
2016 than 999 operands. */
2017 buffer = xstrdup (TREE_STRING_POINTER (string));
2018 p = buffer + (c - TREE_STRING_POINTER (string));
2020 while ((p = strchr (p, '%')) != NULL)
2024 else if (ISALPHA (p[1]) && p[2] == '[')
2032 p = resolve_operand_name_1 (p, outputs, inputs);
2035 string = build_string (strlen (buffer), buffer);
2042 /* A subroutine of resolve_operand_names. P points to the '[' for a
2043 potential named operand of the form [<name>]. In place, replace
2044 the name and brackets with a number. Return a pointer to the
2045 balance of the string after substitution. */
2048 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
2055 /* Collect the operand name. */
2056 q = strchr (p, ']');
2059 error ("missing close brace for named operand");
2060 return strchr (p, '\0');
2064 /* Resolve the name to a number. */
2065 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2067 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2070 const char *c = TREE_STRING_POINTER (name);
2071 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2075 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2077 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2080 const char *c = TREE_STRING_POINTER (name);
2081 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2087 error ("undefined named operand '%s'", p + 1);
2091 /* Replace the name with the number. Unfortunately, not all libraries
2092 get the return value of sprintf correct, so search for the end of the
2093 generated string by hand. */
2094 sprintf (p, "%d", op);
2095 p = strchr (p, '\0');
2097 /* Verify the no extra buffer space assumption. */
2101 /* Shift the rest of the buffer down to fill the gap. */
2102 memmove (p, q + 1, strlen (q + 1) + 1);
2107 /* Generate RTL to evaluate the expression EXP
2108 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2109 Provided just for backward-compatibility. expand_expr_stmt_value()
2110 should be used for new code. */
2113 expand_expr_stmt (tree exp)
2115 expand_expr_stmt_value (exp, -1, 1);
2118 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2119 whether to (1) save the value of the expression, (0) discard it or
2120 (-1) use expr_stmts_for_value to tell. The use of -1 is
2121 deprecated, and retained only for backward compatibility. */
2124 expand_expr_stmt_value (tree exp, int want_value, int maybe_last)
2129 if (want_value == -1)
2130 want_value = expr_stmts_for_value != 0;
2132 /* If -Wextra, warn about statements with no side effects,
2133 except for an explicit cast to void (e.g. for assert()), and
2134 except for last statement in ({...}) where they may be useful. */
2136 && (expr_stmts_for_value == 0 || ! maybe_last)
2137 && exp != error_mark_node
2138 && warn_unused_value)
2140 if (TREE_SIDE_EFFECTS (exp))
2141 warn_if_unused_value (exp);
2142 else if (!VOID_TYPE_P (TREE_TYPE (exp)))
2143 warning ("%Hstatement with no effect", &emit_locus);
2146 /* If EXP is of function type and we are expanding statements for
2147 value, convert it to pointer-to-function. */
2148 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2149 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2151 /* The call to `expand_expr' could cause last_expr_type and
2152 last_expr_value to get reset. Therefore, we set last_expr_value
2153 and last_expr_type *after* calling expand_expr. */
2154 value = expand_expr (exp, want_value ? NULL_RTX : const0_rtx,
2156 type = TREE_TYPE (exp);
2158 /* If all we do is reference a volatile value in memory,
2159 copy it to a register to be sure it is actually touched. */
2160 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2162 if (TYPE_MODE (type) == VOIDmode)
2164 else if (TYPE_MODE (type) != BLKmode)
2165 value = copy_to_reg (value);
2168 rtx lab = gen_label_rtx ();
2170 /* Compare the value with itself to reference it. */
2171 emit_cmp_and_jump_insns (value, value, EQ,
2172 expand_expr (TYPE_SIZE (type),
2173 NULL_RTX, VOIDmode, 0),
2179 /* If this expression is part of a ({...}) and is in memory, we may have
2180 to preserve temporaries. */
2181 preserve_temp_slots (value);
2183 /* Free any temporaries used to evaluate this expression. Any temporary
2184 used as a result of this expression will already have been preserved
2190 last_expr_value = value;
2191 last_expr_type = type;
2197 /* Warn if EXP contains any computations whose results are not used.
2198 Return 1 if a warning is printed; 0 otherwise. */
2201 warn_if_unused_value (tree exp)
2203 if (TREE_USED (exp))
2206 /* Don't warn about void constructs. This includes casting to void,
2207 void function calls, and statement expressions with a final cast
2209 if (VOID_TYPE_P (TREE_TYPE (exp)))
2212 switch (TREE_CODE (exp))
2214 case PREINCREMENT_EXPR:
2215 case POSTINCREMENT_EXPR:
2216 case PREDECREMENT_EXPR:
2217 case POSTDECREMENT_EXPR:
2223 case TRY_CATCH_EXPR:
2224 case WITH_CLEANUP_EXPR:
2229 /* For a binding, warn if no side effect within it. */
2230 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2233 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2235 case TRUTH_ORIF_EXPR:
2236 case TRUTH_ANDIF_EXPR:
2237 /* In && or ||, warn if 2nd operand has no side effect. */
2238 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2241 if (TREE_NO_UNUSED_WARNING (exp))
2243 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2245 /* Let people do `(foo (), 0)' without a warning. */
2246 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2248 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2252 case NON_LVALUE_EXPR:
2253 /* Don't warn about conversions not explicit in the user's program. */
2254 if (TREE_NO_UNUSED_WARNING (exp))
2256 /* Assignment to a cast usually results in a cast of a modify.
2257 Don't complain about that. There can be an arbitrary number of
2258 casts before the modify, so we must loop until we find the first
2259 non-cast expression and then test to see if that is a modify. */
2261 tree tem = TREE_OPERAND (exp, 0);
2263 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2264 tem = TREE_OPERAND (tem, 0);
2266 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2267 || TREE_CODE (tem) == CALL_EXPR)
2273 /* Don't warn about automatic dereferencing of references, since
2274 the user cannot control it. */
2275 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2276 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2280 /* Referencing a volatile value is a side effect, so don't warn. */
2282 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2283 && TREE_THIS_VOLATILE (exp))
2286 /* If this is an expression which has no operands, there is no value
2287 to be unused. There are no such language-independent codes,
2288 but front ends may define such. */
2289 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2290 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2294 /* If this is an expression with side effects, don't warn. */
2295 if (TREE_SIDE_EFFECTS (exp))
2298 warning ("%Hvalue computed is not used", &emit_locus);
2303 /* Clear out the memory of the last expression evaluated. */
2306 clear_last_expr (void)
2308 last_expr_type = NULL_TREE;
2309 last_expr_value = NULL_RTX;
2312 /* Begin a statement-expression, i.e., a series of statements which
2313 may return a value. Return the RTL_EXPR for this statement expr.
2314 The caller must save that value and pass it to
2315 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2316 in the statement-expression are deallocated at the end of the
2320 expand_start_stmt_expr (int has_scope)
2324 /* Make the RTL_EXPR node temporary, not momentary,
2325 so that rtl_expr_chain doesn't become garbage. */
2326 t = make_node (RTL_EXPR);
2327 do_pending_stack_adjust ();
2329 start_sequence_for_rtl_expr (t);
2333 expr_stmts_for_value++;
2337 /* Restore the previous state at the end of a statement that returns a value.
2338 Returns a tree node representing the statement's value and the
2339 insns to compute the value.
2341 The nodes of that expression have been freed by now, so we cannot use them.
2342 But we don't want to do that anyway; the expression has already been
2343 evaluated and now we just want to use the value. So generate a RTL_EXPR
2344 with the proper type and RTL value.
2346 If the last substatement was not an expression,
2347 return something with type `void'. */
2350 expand_end_stmt_expr (tree t)
2354 if (! last_expr_value || ! last_expr_type)
2356 last_expr_value = const0_rtx;
2357 last_expr_type = void_type_node;
2359 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2360 /* Remove any possible QUEUED. */
2361 last_expr_value = protect_from_queue (last_expr_value, 0);
2365 TREE_TYPE (t) = last_expr_type;
2366 RTL_EXPR_RTL (t) = last_expr_value;
2367 RTL_EXPR_SEQUENCE (t) = get_insns ();
2369 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2373 /* Don't consider deleting this expr or containing exprs at tree level. */
2374 TREE_SIDE_EFFECTS (t) = 1;
2375 /* Propagate volatility of the actual RTL expr. */
2376 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2379 expr_stmts_for_value--;
2384 /* Generate RTL for the start of an if-then. COND is the expression
2385 whose truth should be tested.
2387 If EXITFLAG is nonzero, this conditional is visible to
2388 `exit_something'. */
2391 expand_start_cond (tree cond, int exitflag)
2393 struct nesting *thiscond = ALLOC_NESTING ();
2395 /* Make an entry on cond_stack for the cond we are entering. */
2397 thiscond->desc = COND_NESTING;
2398 thiscond->next = cond_stack;
2399 thiscond->all = nesting_stack;
2400 thiscond->depth = ++nesting_depth;
2401 thiscond->data.cond.next_label = gen_label_rtx ();
2402 /* Before we encounter an `else', we don't need a separate exit label
2403 unless there are supposed to be exit statements
2404 to exit this conditional. */
2405 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2406 thiscond->data.cond.endif_label = thiscond->exit_label;
2407 cond_stack = thiscond;
2408 nesting_stack = thiscond;
2410 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2413 /* Generate RTL between then-clause and the elseif-clause
2414 of an if-then-elseif-.... */
2417 expand_start_elseif (tree cond)
2419 if (cond_stack->data.cond.endif_label == 0)
2420 cond_stack->data.cond.endif_label = gen_label_rtx ();
2421 emit_jump (cond_stack->data.cond.endif_label);
2422 emit_label (cond_stack->data.cond.next_label);
2423 cond_stack->data.cond.next_label = gen_label_rtx ();
2424 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2427 /* Generate RTL between the then-clause and the else-clause
2428 of an if-then-else. */
2431 expand_start_else (void)
2433 if (cond_stack->data.cond.endif_label == 0)
2434 cond_stack->data.cond.endif_label = gen_label_rtx ();
2436 emit_jump (cond_stack->data.cond.endif_label);
2437 emit_label (cond_stack->data.cond.next_label);
2438 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2441 /* After calling expand_start_else, turn this "else" into an "else if"
2442 by providing another condition. */
2445 expand_elseif (tree cond)
2447 cond_stack->data.cond.next_label = gen_label_rtx ();
2448 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2451 /* Generate RTL for the end of an if-then.
2452 Pop the record for it off of cond_stack. */
2455 expand_end_cond (void)
2457 struct nesting *thiscond = cond_stack;
2459 do_pending_stack_adjust ();
2460 if (thiscond->data.cond.next_label)
2461 emit_label (thiscond->data.cond.next_label);
2462 if (thiscond->data.cond.endif_label)
2463 emit_label (thiscond->data.cond.endif_label);
2465 POPSTACK (cond_stack);
2469 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2470 loop should be exited by `exit_something'. This is a loop for which
2471 `expand_continue' will jump to the top of the loop.
2473 Make an entry on loop_stack to record the labels associated with
2477 expand_start_loop (int exit_flag)
2479 struct nesting *thisloop = ALLOC_NESTING ();
2481 /* Make an entry on loop_stack for the loop we are entering. */
2483 thisloop->desc = LOOP_NESTING;
2484 thisloop->next = loop_stack;
2485 thisloop->all = nesting_stack;
2486 thisloop->depth = ++nesting_depth;
2487 thisloop->data.loop.start_label = gen_label_rtx ();
2488 thisloop->data.loop.end_label = gen_label_rtx ();
2489 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2490 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2491 loop_stack = thisloop;
2492 nesting_stack = thisloop;
2494 do_pending_stack_adjust ();
2496 emit_note (NOTE_INSN_LOOP_BEG);
2497 emit_label (thisloop->data.loop.start_label);
2502 /* Like expand_start_loop but for a loop where the continuation point
2503 (for expand_continue_loop) will be specified explicitly. */
2506 expand_start_loop_continue_elsewhere (int exit_flag)
2508 struct nesting *thisloop = expand_start_loop (exit_flag);
2509 loop_stack->data.loop.continue_label = gen_label_rtx ();
2513 /* Begin a null, aka do { } while (0) "loop". But since the contents
2514 of said loop can still contain a break, we must frob the loop nest. */
2517 expand_start_null_loop (void)
2519 struct nesting *thisloop = ALLOC_NESTING ();
2521 /* Make an entry on loop_stack for the loop we are entering. */
2523 thisloop->desc = LOOP_NESTING;
2524 thisloop->next = loop_stack;
2525 thisloop->all = nesting_stack;
2526 thisloop->depth = ++nesting_depth;
2527 thisloop->data.loop.start_label = emit_note (NOTE_INSN_DELETED);
2528 thisloop->data.loop.end_label = gen_label_rtx ();
2529 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2530 thisloop->exit_label = thisloop->data.loop.end_label;
2531 loop_stack = thisloop;
2532 nesting_stack = thisloop;
2537 /* Specify the continuation point for a loop started with
2538 expand_start_loop_continue_elsewhere.
2539 Use this at the point in the code to which a continue statement
2543 expand_loop_continue_here (void)
2545 do_pending_stack_adjust ();
2546 emit_note (NOTE_INSN_LOOP_CONT);
2547 emit_label (loop_stack->data.loop.continue_label);
2550 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2551 Pop the block off of loop_stack. */
2554 expand_end_loop (void)
2556 rtx start_label = loop_stack->data.loop.start_label;
2558 int eh_regions, debug_blocks;
2561 /* Mark the continue-point at the top of the loop if none elsewhere. */
2562 if (start_label == loop_stack->data.loop.continue_label)
2563 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2565 do_pending_stack_adjust ();
2567 /* If the loop starts with a loop exit, roll that to the end where
2568 it will optimize together with the jump back.
2570 If the loop presently looks like this (in pseudo-C):
2574 if (test) goto end_label;
2580 transform it to look like:
2587 if (test) goto end_label;
2591 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2592 the end of the entry conditional. Without this, our lexical scan
2593 can't tell the difference between an entry conditional and a
2594 body conditional that exits the loop. Mistaking the two means
2595 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2596 screw up loop unrolling.
2598 Things will be oh so much better when loop optimization is done
2599 off of a proper control flow graph... */
2601 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2604 eh_regions = debug_blocks = 0;
2605 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2606 if (GET_CODE (etc_note) == NOTE)
2608 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2611 /* We must not walk into a nested loop. */
2612 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2614 etc_note = NULL_RTX;
2618 /* At the same time, scan for EH region notes, as we don't want
2619 to scrog region nesting. This shouldn't happen, but... */
2620 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2622 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2624 if (--eh_regions < 0)
2625 /* We've come to the end of an EH region, but never saw the
2626 beginning of that region. That means that an EH region
2627 begins before the top of the loop, and ends in the middle
2628 of it. The existence of such a situation violates a basic
2629 assumption in this code, since that would imply that even
2630 when EH_REGIONS is zero, we might move code out of an
2631 exception region. */
2635 /* Likewise for debug scopes. In this case we'll either (1) move
2636 all of the notes if they are properly nested or (2) leave the
2637 notes alone and only rotate the loop at high optimization
2638 levels when we expect to scrog debug info. */
2639 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2641 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2644 else if (INSN_P (etc_note))
2651 && (debug_blocks == 0 || optimize >= 2)
2652 && NEXT_INSN (etc_note) != NULL_RTX
2653 && ! any_condjump_p (get_last_insn ()))
2655 /* We found one. Move everything from START to ETC to the end
2656 of the loop, and add a jump from the top of the loop. */
2657 rtx top_label = gen_label_rtx ();
2658 rtx start_move = start_label;
2660 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2661 then we want to move this note also. */
2662 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2663 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2664 start_move = PREV_INSN (start_move);
2666 emit_label_before (top_label, start_move);
2668 /* Actually move the insns. If the debug scopes are nested, we
2669 can move everything at once. Otherwise we have to move them
2670 one by one and squeeze out the block notes. */
2671 if (debug_blocks == 0)
2672 reorder_insns (start_move, etc_note, get_last_insn ());
2675 rtx insn, next_insn;
2676 for (insn = start_move; insn; insn = next_insn)
2678 /* Figure out which insn comes after this one. We have
2679 to do this before we move INSN. */
2680 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2682 if (GET_CODE (insn) == NOTE
2683 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2684 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2687 reorder_insns (insn, insn, get_last_insn ());
2691 /* Add the jump from the top of the loop. */
2692 emit_jump_insn_before (gen_jump (start_label), top_label);
2693 emit_barrier_before (top_label);
2694 start_label = top_label;
2697 emit_jump (start_label);
2698 emit_note (NOTE_INSN_LOOP_END);
2699 emit_label (loop_stack->data.loop.end_label);
2701 POPSTACK (loop_stack);
2706 /* Finish a null loop, aka do { } while (0). */
2709 expand_end_null_loop (void)
2711 do_pending_stack_adjust ();
2712 emit_label (loop_stack->data.loop.end_label);
2714 POPSTACK (loop_stack);
2719 /* Generate a jump to the current loop's continue-point.
2720 This is usually the top of the loop, but may be specified
2721 explicitly elsewhere. If not currently inside a loop,
2722 return 0 and do nothing; caller will print an error message. */
2725 expand_continue_loop (struct nesting *whichloop)
2727 /* Emit information for branch prediction. */
2730 if (flag_guess_branch_prob)
2732 note = emit_note (NOTE_INSN_PREDICTION);
2733 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2737 whichloop = loop_stack;
2740 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2745 /* Generate a jump to exit the current loop. If not currently inside a loop,
2746 return 0 and do nothing; caller will print an error message. */
2749 expand_exit_loop (struct nesting *whichloop)
2753 whichloop = loop_stack;
2756 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2760 /* Generate a conditional jump to exit the current loop if COND
2761 evaluates to zero. If not currently inside a loop,
2762 return 0 and do nothing; caller will print an error message. */
2765 expand_exit_loop_if_false (struct nesting *whichloop, tree cond)
2771 whichloop = loop_stack;
2775 if (integer_nonzerop (cond))
2777 if (integer_zerop (cond))
2778 return expand_exit_loop (whichloop);
2780 /* Check if we definitely won't need a fixup. */
2781 if (whichloop == nesting_stack)
2783 jumpifnot (cond, whichloop->data.loop.end_label);
2787 /* In order to handle fixups, we actually create a conditional jump
2788 around an unconditional branch to exit the loop. If fixups are
2789 necessary, they go before the unconditional branch. */
2791 label = gen_label_rtx ();
2792 jumpif (cond, label);
2793 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2800 /* Like expand_exit_loop_if_false except also emit a note marking
2801 the end of the conditional. Should only be used immediately
2802 after expand_loop_start. */
2805 expand_exit_loop_top_cond (struct nesting *whichloop, tree cond)
2807 if (! expand_exit_loop_if_false (whichloop, cond))
2810 emit_note (NOTE_INSN_LOOP_END_TOP_COND);
2814 /* Return nonzero if we should preserve sub-expressions as separate
2815 pseudos. We never do so if we aren't optimizing. We always do so
2816 if -fexpensive-optimizations.
2818 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2819 the loop may still be a small one. */
2822 preserve_subexpressions_p (void)
2826 if (flag_expensive_optimizations)
2829 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2832 insn = get_last_insn_anywhere ();
2835 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2836 < n_non_fixed_regs * 3));
2840 /* Generate a jump to exit the current loop, conditional, binding contour
2841 or case statement. Not all such constructs are visible to this function,
2842 only those started with EXIT_FLAG nonzero. Individual languages use
2843 the EXIT_FLAG parameter to control which kinds of constructs you can
2846 If not currently inside anything that can be exited,
2847 return 0 and do nothing; caller will print an error message. */
2850 expand_exit_something (void)
2854 for (n = nesting_stack; n; n = n->all)
2855 if (n->exit_label != 0)
2857 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2864 /* Generate RTL to return from the current function, with no value.
2865 (That is, we do not do anything about returning any value.) */
2868 expand_null_return (void)
2872 last_insn = get_last_insn ();
2874 /* If this function was declared to return a value, but we
2875 didn't, clobber the return registers so that they are not
2876 propagated live to the rest of the function. */
2877 clobber_return_register ();
2879 expand_null_return_1 (last_insn);
2882 /* Try to guess whether the value of return means error code. */
2883 static enum br_predictor
2884 return_prediction (rtx val)
2886 /* Different heuristics for pointers and scalars. */
2887 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2889 /* NULL is usually not returned. */
2890 if (val == const0_rtx)
2891 return PRED_NULL_RETURN;
2895 /* Negative return values are often used to indicate
2897 if (GET_CODE (val) == CONST_INT
2898 && INTVAL (val) < 0)
2899 return PRED_NEGATIVE_RETURN;
2900 /* Constant return values are also usually erors,
2901 zero/one often mean booleans so exclude them from the
2903 if (CONSTANT_P (val)
2904 && (val != const0_rtx && val != const1_rtx))
2905 return PRED_CONST_RETURN;
2907 return PRED_NO_PREDICTION;
2910 /* Generate RTL to return from the current function, with value VAL. */
2913 expand_value_return (rtx val)
2917 enum br_predictor pred;
2919 if (flag_guess_branch_prob
2920 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2922 /* Emit information for branch prediction. */
2925 note = emit_note (NOTE_INSN_PREDICTION);
2927 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2931 last_insn = get_last_insn ();
2932 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2934 /* Copy the value to the return location
2935 unless it's already there. */
2937 if (return_reg != val)
2939 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2940 #ifdef PROMOTE_FUNCTION_RETURN
2941 int unsignedp = TREE_UNSIGNED (type);
2942 enum machine_mode old_mode
2943 = DECL_MODE (DECL_RESULT (current_function_decl));
2944 enum machine_mode mode
2945 = promote_mode (type, old_mode, &unsignedp, 1);
2947 if (mode != old_mode)
2948 val = convert_modes (mode, old_mode, val, unsignedp);
2950 if (GET_CODE (return_reg) == PARALLEL)
2951 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
2953 emit_move_insn (return_reg, val);
2956 expand_null_return_1 (last_insn);
2959 /* Output a return with no value. If LAST_INSN is nonzero,
2960 pretend that the return takes place after LAST_INSN. */
2963 expand_null_return_1 (rtx last_insn)
2965 rtx end_label = cleanup_label ? cleanup_label : return_label;
2967 clear_pending_stack_adjust ();
2968 do_pending_stack_adjust ();
2972 end_label = return_label = gen_label_rtx ();
2973 expand_goto_internal (NULL_TREE, end_label, last_insn);
2976 /* Generate RTL to evaluate the expression RETVAL and return it
2977 from the current function. */
2980 expand_return (tree retval)
2982 /* If there are any cleanups to be performed, then they will
2983 be inserted following LAST_INSN. It is desirable
2984 that the last_insn, for such purposes, should be the
2985 last insn before computing the return value. Otherwise, cleanups
2986 which call functions can clobber the return value. */
2987 /* ??? rms: I think that is erroneous, because in C++ it would
2988 run destructors on variables that might be used in the subsequent
2989 computation of the return value. */
2995 /* If function wants no value, give it none. */
2996 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2998 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3000 expand_null_return ();
3004 if (retval == error_mark_node)
3006 /* Treat this like a return of no value from a function that
3008 expand_null_return ();
3011 else if (TREE_CODE (retval) == RESULT_DECL)
3012 retval_rhs = retval;
3013 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3014 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3015 retval_rhs = TREE_OPERAND (retval, 1);
3016 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3017 /* Recognize tail-recursive call to void function. */
3018 retval_rhs = retval;
3020 retval_rhs = NULL_TREE;
3022 last_insn = get_last_insn ();
3024 /* Distribute return down conditional expr if either of the sides
3025 may involve tail recursion (see test below). This enhances the number
3026 of tail recursions we see. Don't do this always since it can produce
3027 sub-optimal code in some cases and we distribute assignments into
3028 conditional expressions when it would help. */
3030 if (optimize && retval_rhs != 0
3031 && frame_offset == 0
3032 && TREE_CODE (retval_rhs) == COND_EXPR
3033 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3034 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3036 rtx label = gen_label_rtx ();
3039 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3040 start_cleanup_deferral ();
3041 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3042 DECL_RESULT (current_function_decl),
3043 TREE_OPERAND (retval_rhs, 1));
3044 TREE_SIDE_EFFECTS (expr) = 1;
3045 expand_return (expr);
3048 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3049 DECL_RESULT (current_function_decl),
3050 TREE_OPERAND (retval_rhs, 2));
3051 TREE_SIDE_EFFECTS (expr) = 1;
3052 expand_return (expr);
3053 end_cleanup_deferral ();
3057 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3059 /* If the result is an aggregate that is being returned in one (or more)
3060 registers, load the registers here. The compiler currently can't handle
3061 copying a BLKmode value into registers. We could put this code in a
3062 more general area (for use by everyone instead of just function
3063 call/return), but until this feature is generally usable it is kept here
3064 (and in expand_call). The value must go into a pseudo in case there
3065 are cleanups that will clobber the real return register. */
3068 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3069 && GET_CODE (result_rtl) == REG)
3072 unsigned HOST_WIDE_INT bitpos, xbitpos;
3073 unsigned HOST_WIDE_INT big_endian_correction = 0;
3074 unsigned HOST_WIDE_INT bytes
3075 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3076 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3077 unsigned int bitsize
3078 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3079 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
3080 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3081 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3082 enum machine_mode tmpmode, result_reg_mode;
3086 expand_null_return ();
3090 /* Structures whose size is not a multiple of a word are aligned
3091 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
3092 machine, this means we must skip the empty high order bytes when
3093 calculating the bit offset. */
3094 if (BYTES_BIG_ENDIAN
3095 && bytes % UNITS_PER_WORD)
3096 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3099 /* Copy the structure BITSIZE bits at a time. */
3100 for (bitpos = 0, xbitpos = big_endian_correction;
3101 bitpos < bytes * BITS_PER_UNIT;
3102 bitpos += bitsize, xbitpos += bitsize)
3104 /* We need a new destination pseudo each time xbitpos is
3105 on a word boundary and when xbitpos == big_endian_correction
3106 (the first time through). */
3107 if (xbitpos % BITS_PER_WORD == 0
3108 || xbitpos == big_endian_correction)
3110 /* Generate an appropriate register. */
3111 dst = gen_reg_rtx (word_mode);
3112 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3114 /* Clear the destination before we move anything into it. */
3115 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3118 /* We need a new source operand each time bitpos is on a word
3120 if (bitpos % BITS_PER_WORD == 0)
3121 src = operand_subword_force (result_val,
3122 bitpos / BITS_PER_WORD,
3125 /* Use bitpos for the source extraction (left justified) and
3126 xbitpos for the destination store (right justified). */
3127 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3128 extract_bit_field (src, bitsize,
3129 bitpos % BITS_PER_WORD, 1,
3130 NULL_RTX, word_mode, word_mode,
3135 /* Find the smallest integer mode large enough to hold the
3136 entire structure and use that mode instead of BLKmode
3137 on the USE insn for the return register. */
3138 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3139 tmpmode != VOIDmode;
3140 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3141 /* Have we found a large enough mode? */
3142 if (GET_MODE_SIZE (tmpmode) >= bytes)
3145 /* No suitable mode found. */
3146 if (tmpmode == VOIDmode)
3149 PUT_MODE (result_rtl, tmpmode);
3151 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3152 result_reg_mode = word_mode;
3154 result_reg_mode = tmpmode;
3155 result_reg = gen_reg_rtx (result_reg_mode);
3158 for (i = 0; i < n_regs; i++)
3159 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3162 if (tmpmode != result_reg_mode)
3163 result_reg = gen_lowpart (tmpmode, result_reg);
3165 expand_value_return (result_reg);
3167 else if (retval_rhs != 0
3168 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3169 && (GET_CODE (result_rtl) == REG
3170 || (GET_CODE (result_rtl) == PARALLEL)))
3172 /* Calculate the return value into a temporary (usually a pseudo
3174 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3175 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3177 val = assign_temp (nt, 0, 0, 1);
3178 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3179 val = force_not_mem (val);
3181 /* Return the calculated value, doing cleanups first. */
3182 expand_value_return (val);
3186 /* No cleanups or no hard reg used;
3187 calculate value into hard return reg. */
3188 expand_expr (retval, const0_rtx, VOIDmode, 0);
3190 expand_value_return (result_rtl);
3194 /* Attempt to optimize a potential tail recursion call into a goto.
3195 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3196 where to place the jump to the tail recursion label.
3198 Return TRUE if the call was optimized into a goto. */
3201 optimize_tail_recursion (tree arguments, rtx last_insn)
3203 /* Finish checking validity, and if valid emit code to set the
3204 argument variables for the new call. */
3205 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3207 if (tail_recursion_label == 0)
3209 tail_recursion_label = gen_label_rtx ();
3210 emit_label_after (tail_recursion_label,
3211 tail_recursion_reentry);
3214 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3221 /* Emit code to alter this function's formal parms for a tail-recursive call.
3222 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3223 FORMALS is the chain of decls of formals.
3224 Return 1 if this can be done;
3225 otherwise return 0 and do not emit any code. */
3228 tail_recursion_args (tree actuals, tree formals)
3230 tree a = actuals, f = formals;
3234 /* Check that number and types of actuals are compatible
3235 with the formals. This is not always true in valid C code.
3236 Also check that no formal needs to be addressable
3237 and that all formals are scalars. */
3239 /* Also count the args. */
3241 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3243 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3244 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3246 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3249 if (a != 0 || f != 0)
3252 /* Compute all the actuals. */
3254 argvec = alloca (i * sizeof (rtx));
3256 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3257 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3259 /* Find which actual values refer to current values of previous formals.
3260 Copy each of them now, before any formal is changed. */
3262 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3266 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3267 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3273 argvec[i] = copy_to_reg (argvec[i]);
3276 /* Store the values of the actuals into the formals. */
3278 for (f = formals, a = actuals, i = 0; f;
3279 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3281 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3282 emit_move_insn (DECL_RTL (f), argvec[i]);
3285 rtx tmp = argvec[i];
3286 int unsignedp = TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a)));
3287 promote_mode(TREE_TYPE (TREE_VALUE (a)), GET_MODE (tmp),
3289 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3291 tmp = gen_reg_rtx (DECL_MODE (f));
3292 convert_move (tmp, argvec[i], unsignedp);
3294 convert_move (DECL_RTL (f), tmp, unsignedp);
3302 /* Generate the RTL code for entering a binding contour.
3303 The variables are declared one by one, by calls to `expand_decl'.
3305 FLAGS is a bitwise or of the following flags:
3307 1 - Nonzero if this construct should be visible to
3310 2 - Nonzero if this contour does not require a
3311 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3312 language-independent code should set this flag because they
3313 will not create corresponding BLOCK nodes. (There should be
3314 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3315 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3316 when expand_end_bindings is called.
3318 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3319 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3323 expand_start_bindings_and_block (int flags, tree block)
3325 struct nesting *thisblock = ALLOC_NESTING ();
3327 int exit_flag = ((flags & 1) != 0);
3328 int block_flag = ((flags & 2) == 0);
3330 /* If a BLOCK is supplied, then the caller should be requesting a
3331 NOTE_INSN_BLOCK_BEG note. */
3332 if (!block_flag && block)
3335 /* Create a note to mark the beginning of the block. */
3338 note = emit_note (NOTE_INSN_BLOCK_BEG);
3339 NOTE_BLOCK (note) = block;
3342 note = emit_note (NOTE_INSN_DELETED);
3344 /* Make an entry on block_stack for the block we are entering. */
3346 thisblock->desc = BLOCK_NESTING;
3347 thisblock->next = block_stack;
3348 thisblock->all = nesting_stack;
3349 thisblock->depth = ++nesting_depth;
3350 thisblock->data.block.stack_level = 0;
3351 thisblock->data.block.cleanups = 0;
3352 thisblock->data.block.exception_region = 0;
3353 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3355 thisblock->data.block.conditional_code = 0;
3356 thisblock->data.block.last_unconditional_cleanup = note;
3357 /* When we insert instructions after the last unconditional cleanup,
3358 we don't adjust last_insn. That means that a later add_insn will
3359 clobber the instructions we've just added. The easiest way to
3360 fix this is to just insert another instruction here, so that the
3361 instructions inserted after the last unconditional cleanup are
3362 never the last instruction. */
3363 emit_note (NOTE_INSN_DELETED);
3366 && !(block_stack->data.block.cleanups == NULL_TREE
3367 && block_stack->data.block.outer_cleanups == NULL_TREE))
3368 thisblock->data.block.outer_cleanups
3369 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3370 block_stack->data.block.outer_cleanups);
3372 thisblock->data.block.outer_cleanups = 0;
3373 thisblock->data.block.label_chain = 0;
3374 thisblock->data.block.innermost_stack_block = stack_block_stack;
3375 thisblock->data.block.first_insn = note;
3376 thisblock->data.block.block_start_count = ++current_block_start_count;
3377 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3378 block_stack = thisblock;
3379 nesting_stack = thisblock;
3381 /* Make a new level for allocating stack slots. */
3385 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3386 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3387 expand_expr are made. After we end the region, we know that all
3388 space for all temporaries that were created by TARGET_EXPRs will be
3389 destroyed and their space freed for reuse. */
3392 expand_start_target_temps (void)
3394 /* This is so that even if the result is preserved, the space
3395 allocated will be freed, as we know that it is no longer in use. */
3398 /* Start a new binding layer that will keep track of all cleanup
3399 actions to be performed. */
3400 expand_start_bindings (2);
3402 target_temp_slot_level = temp_slot_level;
3406 expand_end_target_temps (void)
3408 expand_end_bindings (NULL_TREE, 0, 0);
3410 /* This is so that even if the result is preserved, the space
3411 allocated will be freed, as we know that it is no longer in use. */
3415 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3416 in question represents the outermost pair of curly braces (i.e. the "body
3417 block") of a function or method.
3419 For any BLOCK node representing a "body block" of a function or method, the
3420 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3421 represents the outermost (function) scope for the function or method (i.e.
3422 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3423 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3426 is_body_block (tree stmt)
3428 if (lang_hooks.no_body_blocks)
3431 if (TREE_CODE (stmt) == BLOCK)
3433 tree parent = BLOCK_SUPERCONTEXT (stmt);
3435 if (parent && TREE_CODE (parent) == BLOCK)
3437 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3439 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3447 /* True if we are currently emitting insns in an area of output code
3448 that is controlled by a conditional expression. This is used by
3449 the cleanup handling code to generate conditional cleanup actions. */
3452 conditional_context (void)
3454 return block_stack && block_stack->data.block.conditional_code;
3457 /* Return an opaque pointer to the current nesting level, so frontend code
3458 can check its own sanity. */
3461 current_nesting_level (void)
3463 return cfun ? block_stack : 0;
3466 /* Emit a handler label for a nonlocal goto handler.
3467 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3470 expand_nl_handler_label (rtx slot, rtx before_insn)
3473 rtx handler_label = gen_label_rtx ();
3475 /* Don't let cleanup_cfg delete the handler. */
3476 LABEL_PRESERVE_P (handler_label) = 1;
3479 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3480 insns = get_insns ();
3482 emit_insn_before (insns, before_insn);
3484 emit_label (handler_label);
3486 return handler_label;
3489 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3492 expand_nl_goto_receiver (void)
3494 #ifdef HAVE_nonlocal_goto
3495 if (! HAVE_nonlocal_goto)
3497 /* First adjust our frame pointer to its actual value. It was
3498 previously set to the start of the virtual area corresponding to
3499 the stacked variables when we branched here and now needs to be
3500 adjusted to the actual hardware fp value.
3502 Assignments are to virtual registers are converted by
3503 instantiate_virtual_regs into the corresponding assignment
3504 to the underlying register (fp in this case) that makes
3505 the original assignment true.
3506 So the following insn will actually be
3507 decrementing fp by STARTING_FRAME_OFFSET. */
3508 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3510 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3511 if (fixed_regs[ARG_POINTER_REGNUM])
3513 #ifdef ELIMINABLE_REGS
3514 /* If the argument pointer can be eliminated in favor of the
3515 frame pointer, we don't need to restore it. We assume here
3516 that if such an elimination is present, it can always be used.
3517 This is the case on all known machines; if we don't make this
3518 assumption, we do unnecessary saving on many machines. */
3519 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3522 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3523 if (elim_regs[i].from == ARG_POINTER_REGNUM
3524 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3527 if (i == ARRAY_SIZE (elim_regs))
3530 /* Now restore our arg pointer from the address at which it
3531 was saved in our stack frame. */
3532 emit_move_insn (virtual_incoming_args_rtx,
3533 copy_to_reg (get_arg_pointer_save_area (cfun)));
3538 #ifdef HAVE_nonlocal_goto_receiver
3539 if (HAVE_nonlocal_goto_receiver)
3540 emit_insn (gen_nonlocal_goto_receiver ());
3544 /* Make handlers for nonlocal gotos taking place in the function calls in
3548 expand_nl_goto_receivers (struct nesting *thisblock)
3551 rtx afterward = gen_label_rtx ();
3556 /* Record the handler address in the stack slot for that purpose,
3557 during this block, saving and restoring the outer value. */
3558 if (thisblock->next != 0)
3559 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3561 rtx save_receiver = gen_reg_rtx (Pmode);
3562 emit_move_insn (XEXP (slot, 0), save_receiver);
3565 emit_move_insn (save_receiver, XEXP (slot, 0));
3566 insns = get_insns ();
3568 emit_insn_before (insns, thisblock->data.block.first_insn);
3571 /* Jump around the handlers; they run only when specially invoked. */
3572 emit_jump (afterward);
3574 /* Make a separate handler for each label. */
3575 link = nonlocal_labels;
3576 slot = nonlocal_goto_handler_slots;
3577 label_list = NULL_RTX;
3578 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3579 /* Skip any labels we shouldn't be able to jump to from here,
3580 we generate one special handler for all of them below which just calls
3582 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3585 lab = expand_nl_handler_label (XEXP (slot, 0),
3586 thisblock->data.block.first_insn);
3587 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3589 expand_nl_goto_receiver ();
3591 /* Jump to the "real" nonlocal label. */
3592 expand_goto (TREE_VALUE (link));
3595 /* A second pass over all nonlocal labels; this time we handle those
3596 we should not be able to jump to at this point. */
3597 link = nonlocal_labels;
3598 slot = nonlocal_goto_handler_slots;
3600 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3601 if (DECL_TOO_LATE (TREE_VALUE (link)))
3604 lab = expand_nl_handler_label (XEXP (slot, 0),
3605 thisblock->data.block.first_insn);
3606 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3612 expand_nl_goto_receiver ();
3613 expand_builtin_trap ();
3616 nonlocal_goto_handler_labels = label_list;
3617 emit_label (afterward);
3620 /* Warn about any unused VARS (which may contain nodes other than
3621 VAR_DECLs, but such nodes are ignored). The nodes are connected
3622 via the TREE_CHAIN field. */
3625 warn_about_unused_variables (tree vars)
3629 if (warn_unused_variable)
3630 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3631 if (TREE_CODE (decl) == VAR_DECL
3632 && ! TREE_USED (decl)
3633 && ! DECL_IN_SYSTEM_HEADER (decl)
3634 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3635 warning ("%Hunused variable '%D'", &DECL_SOURCE_LOCATION (decl), decl);
3638 /* Generate RTL code to terminate a binding contour.
3640 VARS is the chain of VAR_DECL nodes for the variables bound in this
3641 contour. There may actually be other nodes in this chain, but any
3642 nodes other than VAR_DECLS are ignored.
3644 MARK_ENDS is nonzero if we should put a note at the beginning
3645 and end of this binding contour.
3647 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3648 zero if we can jump into this contour only if it does not have a saved
3649 stack level, and negative if we are not to check for invalid use of
3650 labels (because the front end does that). */
3653 expand_end_bindings (tree vars, int mark_ends, int dont_jump_in)
3655 struct nesting *thisblock = block_stack;
3657 /* If any of the variables in this scope were not used, warn the
3659 warn_about_unused_variables (vars);
3661 if (thisblock->exit_label)
3663 do_pending_stack_adjust ();
3664 emit_label (thisblock->exit_label);
3667 /* If necessary, make handlers for nonlocal gotos taking
3668 place in the function calls in this block. */
3669 if (function_call_count != 0 && nonlocal_labels
3670 /* Make handler for outermost block
3671 if there were any nonlocal gotos to this function. */
3672 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3673 /* Make handler for inner block if it has something
3674 special to do when you jump out of it. */
3675 : (thisblock->data.block.cleanups != 0
3676 || thisblock->data.block.stack_level != 0)))
3677 expand_nl_goto_receivers (thisblock);
3679 /* Don't allow jumping into a block that has a stack level.
3680 Cleanups are allowed, though. */
3681 if (dont_jump_in > 0
3682 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3684 struct label_chain *chain;
3686 /* Any labels in this block are no longer valid to go to.
3687 Mark them to cause an error message. */
3688 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3690 DECL_TOO_LATE (chain->label) = 1;
3691 /* If any goto without a fixup came to this label,
3692 that must be an error, because gotos without fixups
3693 come from outside all saved stack-levels. */
3694 if (TREE_ADDRESSABLE (chain->label))
3695 error ("%Hlabel '%D' used before containing binding contour",
3696 &DECL_SOURCE_LOCATION (chain->label), chain->label);
3700 /* Restore stack level in effect before the block
3701 (only if variable-size objects allocated). */
3702 /* Perform any cleanups associated with the block. */
3704 if (thisblock->data.block.stack_level != 0
3705 || thisblock->data.block.cleanups != 0)
3710 /* Don't let cleanups affect ({...}) constructs. */
3711 int old_expr_stmts_for_value = expr_stmts_for_value;
3712 rtx old_last_expr_value = last_expr_value;
3713 tree old_last_expr_type = last_expr_type;
3714 expr_stmts_for_value = 0;
3716 /* Only clean up here if this point can actually be reached. */
3717 insn = get_last_insn ();
3718 if (GET_CODE (insn) == NOTE)
3719 insn = prev_nonnote_insn (insn);
3720 reachable = (! insn || GET_CODE (insn) != BARRIER);
3722 /* Do the cleanups. */
3723 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3725 do_pending_stack_adjust ();
3727 expr_stmts_for_value = old_expr_stmts_for_value;
3728 last_expr_value = old_last_expr_value;
3729 last_expr_type = old_last_expr_type;
3731 /* Restore the stack level. */
3733 if (reachable && thisblock->data.block.stack_level != 0)
3735 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3736 thisblock->data.block.stack_level, NULL_RTX);
3737 if (nonlocal_goto_handler_slots != 0)
3738 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3742 /* Any gotos out of this block must also do these things.
3743 Also report any gotos with fixups that came to labels in this
3745 fixup_gotos (thisblock,
3746 thisblock->data.block.stack_level,
3747 thisblock->data.block.cleanups,
3748 thisblock->data.block.first_insn,
3752 /* Mark the beginning and end of the scope if requested.
3753 We do this now, after running cleanups on the variables
3754 just going out of scope, so they are in scope for their cleanups. */
3758 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3759 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3762 /* Get rid of the beginning-mark if we don't make an end-mark. */
3763 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3765 /* Restore the temporary level of TARGET_EXPRs. */
3766 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3768 /* Restore block_stack level for containing block. */
3770 stack_block_stack = thisblock->data.block.innermost_stack_block;
3771 POPSTACK (block_stack);
3773 /* Pop the stack slot nesting and free any slots at this level. */
3777 /* Generate code to save the stack pointer at the start of the current block
3778 and set up to restore it on exit. */
3781 save_stack_pointer (void)
3783 struct nesting *thisblock = block_stack;
3785 if (thisblock->data.block.stack_level == 0)
3787 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3788 &thisblock->data.block.stack_level,
3789 thisblock->data.block.first_insn);
3790 stack_block_stack = thisblock;
3794 /* Generate RTL for the automatic variable declaration DECL.
3795 (Other kinds of declarations are simply ignored if seen here.) */
3798 expand_decl (tree decl)
3802 type = TREE_TYPE (decl);
3804 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3805 type in case this node is used in a reference. */
3806 if (TREE_CODE (decl) == CONST_DECL)
3808 DECL_MODE (decl) = TYPE_MODE (type);
3809 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3810 DECL_SIZE (decl) = TYPE_SIZE (type);
3811 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3815 /* Otherwise, only automatic variables need any expansion done. Static and
3816 external variables, and external functions, will be handled by
3817 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3818 nothing. PARM_DECLs are handled in `assign_parms'. */
3819 if (TREE_CODE (decl) != VAR_DECL)
3822 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3825 /* Create the RTL representation for the variable. */
3827 if (type == error_mark_node)
3828 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3830 else if (DECL_SIZE (decl) == 0)
3831 /* Variable with incomplete type. */
3834 if (DECL_INITIAL (decl) == 0)
3835 /* Error message was already done; now avoid a crash. */
3836 x = gen_rtx_MEM (BLKmode, const0_rtx);
3838 /* An initializer is going to decide the size of this array.
3839 Until we know the size, represent its address with a reg. */
3840 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3842 set_mem_attributes (x, decl, 1);
3843 SET_DECL_RTL (decl, x);
3845 else if (DECL_MODE (decl) != BLKmode
3846 /* If -ffloat-store, don't put explicit float vars
3848 && !(flag_float_store
3849 && TREE_CODE (type) == REAL_TYPE)
3850 && ! TREE_THIS_VOLATILE (decl)
3851 && ! DECL_NONLOCAL (decl)
3852 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3854 /* Automatic variable that can go in a register. */
3855 int unsignedp = TREE_UNSIGNED (type);
3856 enum machine_mode reg_mode
3857 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3859 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3861 if (!DECL_ARTIFICIAL (decl))
3862 mark_user_reg (DECL_RTL (decl));
3864 if (POINTER_TYPE_P (type))
3865 mark_reg_pointer (DECL_RTL (decl),
3866 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3868 maybe_set_unchanging (DECL_RTL (decl), decl);
3870 /* If something wants our address, try to use ADDRESSOF. */
3871 if (TREE_ADDRESSABLE (decl))
3872 put_var_into_stack (decl, /*rescan=*/false);
3875 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3876 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3877 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3878 STACK_CHECK_MAX_VAR_SIZE)))
3880 /* Variable of fixed size that goes on the stack. */
3885 /* If we previously made RTL for this decl, it must be an array
3886 whose size was determined by the initializer.
3887 The old address was a register; set that register now
3888 to the proper address. */
3889 if (DECL_RTL_SET_P (decl))
3891 if (GET_CODE (DECL_RTL (decl)) != MEM
3892 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3894 oldaddr = XEXP (DECL_RTL (decl), 0);
3897 /* Set alignment we actually gave this decl. */
3898 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3899 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3900 DECL_USER_ALIGN (decl) = 0;
3902 x = assign_temp (decl, 1, 1, 1);
3903 set_mem_attributes (x, decl, 1);
3904 SET_DECL_RTL (decl, x);
3908 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3909 if (addr != oldaddr)
3910 emit_move_insn (oldaddr, addr);
3914 /* Dynamic-size object: must push space on the stack. */
3916 rtx address, size, x;
3918 /* Record the stack pointer on entry to block, if have
3919 not already done so. */
3920 do_pending_stack_adjust ();
3921 save_stack_pointer ();
3923 /* In function-at-a-time mode, variable_size doesn't expand this,
3925 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3926 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3927 const0_rtx, VOIDmode, 0);
3929 /* Compute the variable's size, in bytes. */
3930 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
3933 /* Allocate space on the stack for the variable. Note that
3934 DECL_ALIGN says how the variable is to be aligned and we
3935 cannot use it to conclude anything about the alignment of
3937 address = allocate_dynamic_stack_space (size, NULL_RTX,
3938 TYPE_ALIGN (TREE_TYPE (decl)));
3940 /* Reference the variable indirect through that rtx. */
3941 x = gen_rtx_MEM (DECL_MODE (decl), address);
3942 set_mem_attributes (x, decl, 1);
3943 SET_DECL_RTL (decl, x);
3946 /* Indicate the alignment we actually gave this variable. */
3947 #ifdef STACK_BOUNDARY
3948 DECL_ALIGN (decl) = STACK_BOUNDARY;
3950 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3952 DECL_USER_ALIGN (decl) = 0;
3956 /* Emit code to perform the initialization of a declaration DECL. */
3959 expand_decl_init (tree decl)
3961 int was_used = TREE_USED (decl);
3963 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
3964 for static decls. */
3965 if (TREE_CODE (decl) == CONST_DECL
3966 || TREE_STATIC (decl))
3969 /* Compute and store the initial value now. */
3973 if (DECL_INITIAL (decl) == error_mark_node)
3975 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3977 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3978 || code == POINTER_TYPE || code == REFERENCE_TYPE)
3979 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3983 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3985 emit_line_note (DECL_SOURCE_LOCATION (decl));
3986 expand_assignment (decl, DECL_INITIAL (decl), 0);
3990 /* Don't let the initialization count as "using" the variable. */
3991 TREE_USED (decl) = was_used;
3993 /* Free any temporaries we made while initializing the decl. */
3994 preserve_temp_slots (NULL_RTX);
3999 /* CLEANUP is an expression to be executed at exit from this binding contour;
4000 for example, in C++, it might call the destructor for this variable.
4002 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4003 CLEANUP multiple times, and have the correct semantics. This
4004 happens in exception handling, for gotos, returns, breaks that
4005 leave the current scope.
4007 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4008 that is not associated with any particular variable. */
4011 expand_decl_cleanup (tree decl, tree cleanup)
4013 struct nesting *thisblock;
4015 /* Error if we are not in any block. */
4016 if (cfun == 0 || block_stack == 0)
4019 thisblock = block_stack;
4021 /* Record the cleanup if there is one. */
4027 tree *cleanups = &thisblock->data.block.cleanups;
4028 int cond_context = conditional_context ();
4032 rtx flag = gen_reg_rtx (word_mode);
4037 emit_move_insn (flag, const0_rtx);
4038 set_flag_0 = get_insns ();
4041 thisblock->data.block.last_unconditional_cleanup
4042 = emit_insn_after (set_flag_0,
4043 thisblock->data.block.last_unconditional_cleanup);
4045 emit_move_insn (flag, const1_rtx);
4047 cond = build_decl (VAR_DECL, NULL_TREE,
4048 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4049 SET_DECL_RTL (cond, flag);
4051 /* Conditionalize the cleanup. */
4052 cleanup = build (COND_EXPR, void_type_node,
4053 (*lang_hooks.truthvalue_conversion) (cond),
4054 cleanup, integer_zero_node);
4055 cleanup = fold (cleanup);
4057 cleanups = &thisblock->data.block.cleanups;
4060 cleanup = unsave_expr (cleanup);
4062 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4065 /* If this block has a cleanup, it belongs in stack_block_stack. */
4066 stack_block_stack = thisblock;
4073 if (! using_eh_for_cleanups_p)
4074 TREE_ADDRESSABLE (t) = 1;
4076 expand_eh_region_start ();
4083 thisblock->data.block.last_unconditional_cleanup
4084 = emit_insn_after (seq,
4085 thisblock->data.block.last_unconditional_cleanup);
4089 thisblock->data.block.last_unconditional_cleanup
4091 /* When we insert instructions after the last unconditional cleanup,
4092 we don't adjust last_insn. That means that a later add_insn will
4093 clobber the instructions we've just added. The easiest way to
4094 fix this is to just insert another instruction here, so that the
4095 instructions inserted after the last unconditional cleanup are
4096 never the last instruction. */
4097 emit_note (NOTE_INSN_DELETED);
4103 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4107 expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only)
4109 int ret = expand_decl_cleanup (decl, cleanup);
4112 tree node = block_stack->data.block.cleanups;
4113 CLEANUP_EH_ONLY (node) = eh_only;
4118 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4119 DECL_ELTS is the list of elements that belong to DECL's type.
4120 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4123 expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts)
4125 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4129 /* If any of the elements are addressable, so is the entire union. */
4130 for (t = decl_elts; t; t = TREE_CHAIN (t))
4131 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4133 TREE_ADDRESSABLE (decl) = 1;
4138 expand_decl_cleanup (decl, cleanup);
4139 x = DECL_RTL (decl);
4141 /* Go through the elements, assigning RTL to each. */
4142 for (t = decl_elts; t; t = TREE_CHAIN (t))
4144 tree decl_elt = TREE_VALUE (t);
4145 tree cleanup_elt = TREE_PURPOSE (t);
4146 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4148 /* If any of the elements are addressable, so is the entire
4150 if (TREE_USED (decl_elt))
4151 TREE_USED (decl) = 1;
4153 /* Propagate the union's alignment to the elements. */
4154 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4155 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4157 /* If the element has BLKmode and the union doesn't, the union is
4158 aligned such that the element doesn't need to have BLKmode, so
4159 change the element's mode to the appropriate one for its size. */
4160 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4161 DECL_MODE (decl_elt) = mode
4162 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4164 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4165 instead create a new MEM rtx with the proper mode. */
4166 if (GET_CODE (x) == MEM)
4168 if (mode == GET_MODE (x))
4169 SET_DECL_RTL (decl_elt, x);
4171 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4173 else if (GET_CODE (x) == REG)
4175 if (mode == GET_MODE (x))
4176 SET_DECL_RTL (decl_elt, x);
4178 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4183 /* Record the cleanup if there is one. */
4186 thisblock->data.block.cleanups
4187 = tree_cons (decl_elt, cleanup_elt,
4188 thisblock->data.block.cleanups);
4192 /* Expand a list of cleanups LIST.
4193 Elements may be expressions or may be nested lists.
4195 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4196 goto and handle protection regions specially in that case.
4198 If REACHABLE, we emit code, otherwise just inform the exception handling
4199 code about this finalization. */
4202 expand_cleanups (tree list, int in_fixup, int reachable)
4205 for (tail = list; tail; tail = TREE_CHAIN (tail))
4206 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4207 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
4210 if (! in_fixup && using_eh_for_cleanups_p)
4211 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4213 if (reachable && !CLEANUP_EH_ONLY (tail))
4215 /* Cleanups may be run multiple times. For example,
4216 when exiting a binding contour, we expand the
4217 cleanups associated with that contour. When a goto
4218 within that binding contour has a target outside that
4219 contour, it will expand all cleanups from its scope to
4220 the target. Though the cleanups are expanded multiple
4221 times, the control paths are non-overlapping so the
4222 cleanups will not be executed twice. */
4224 /* We may need to protect from outer cleanups. */
4225 if (in_fixup && using_eh_for_cleanups_p)
4227 expand_eh_region_start ();
4229 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4231 expand_eh_region_end_fixup (TREE_VALUE (tail));
4234 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4241 /* Mark when the context we are emitting RTL for as a conditional
4242 context, so that any cleanup actions we register with
4243 expand_decl_init will be properly conditionalized when those
4244 cleanup actions are later performed. Must be called before any
4245 expression (tree) is expanded that is within a conditional context. */
4248 start_cleanup_deferral (void)
4250 /* block_stack can be NULL if we are inside the parameter list. It is
4251 OK to do nothing, because cleanups aren't possible here. */
4253 ++block_stack->data.block.conditional_code;
4256 /* Mark the end of a conditional region of code. Because cleanup
4257 deferrals may be nested, we may still be in a conditional region
4258 after we end the currently deferred cleanups, only after we end all
4259 deferred cleanups, are we back in unconditional code. */
4262 end_cleanup_deferral (void)
4264 /* block_stack can be NULL if we are inside the parameter list. It is
4265 OK to do nothing, because cleanups aren't possible here. */
4267 --block_stack->data.block.conditional_code;
4271 last_cleanup_this_contour (void)
4273 if (block_stack == 0)
4276 return block_stack->data.block.cleanups;
4279 /* Return 1 if there are any pending cleanups at this point.
4280 Check the current contour as well as contours that enclose
4281 the current contour. */
4284 any_pending_cleanups (void)
4286 struct nesting *block;
4288 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4291 if (block_stack->data.block.cleanups != NULL)
4294 if (block_stack->data.block.outer_cleanups == 0)
4297 for (block = block_stack->next; block; block = block->next)
4298 if (block->data.block.cleanups != 0)
4304 /* Enter a case (Pascal) or switch (C) statement.
4305 Push a block onto case_stack and nesting_stack
4306 to accumulate the case-labels that are seen
4307 and to record the labels generated for the statement.
4309 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4310 Otherwise, this construct is transparent for `exit_something'.
4312 EXPR is the index-expression to be dispatched on.
4313 TYPE is its nominal type. We could simply convert EXPR to this type,
4314 but instead we take short cuts. */
4317 expand_start_case (int exit_flag, tree expr, tree type,
4318 const char *printname)
4320 struct nesting *thiscase = ALLOC_NESTING ();
4322 /* Make an entry on case_stack for the case we are entering. */
4324 thiscase->desc = CASE_NESTING;
4325 thiscase->next = case_stack;
4326 thiscase->all = nesting_stack;
4327 thiscase->depth = ++nesting_depth;
4328 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4329 thiscase->data.case_stmt.case_list = 0;
4330 thiscase->data.case_stmt.index_expr = expr;
4331 thiscase->data.case_stmt.nominal_type = type;
4332 thiscase->data.case_stmt.default_label = 0;
4333 thiscase->data.case_stmt.printname = printname;
4334 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4335 case_stack = thiscase;
4336 nesting_stack = thiscase;
4338 do_pending_stack_adjust ();
4341 /* Make sure case_stmt.start points to something that won't
4342 need any transformation before expand_end_case. */
4343 if (GET_CODE (get_last_insn ()) != NOTE)
4344 emit_note (NOTE_INSN_DELETED);
4346 thiscase->data.case_stmt.start = get_last_insn ();
4348 start_cleanup_deferral ();
4351 /* Start a "dummy case statement" within which case labels are invalid
4352 and are not connected to any larger real case statement.
4353 This can be used if you don't want to let a case statement jump
4354 into the middle of certain kinds of constructs. */
4357 expand_start_case_dummy (void)
4359 struct nesting *thiscase = ALLOC_NESTING ();
4361 /* Make an entry on case_stack for the dummy. */
4363 thiscase->desc = CASE_NESTING;
4364 thiscase->next = case_stack;
4365 thiscase->all = nesting_stack;
4366 thiscase->depth = ++nesting_depth;
4367 thiscase->exit_label = 0;
4368 thiscase->data.case_stmt.case_list = 0;
4369 thiscase->data.case_stmt.start = 0;
4370 thiscase->data.case_stmt.nominal_type = 0;
4371 thiscase->data.case_stmt.default_label = 0;
4372 case_stack = thiscase;
4373 nesting_stack = thiscase;
4374 start_cleanup_deferral ();
4378 check_seenlabel (void)
4380 /* If this is the first label, warn if any insns have been emitted. */
4381 if (case_stack->data.case_stmt.line_number_status >= 0)
4385 restore_line_number_status
4386 (case_stack->data.case_stmt.line_number_status);
4387 case_stack->data.case_stmt.line_number_status = -1;
4389 for (insn = case_stack->data.case_stmt.start;
4391 insn = NEXT_INSN (insn))
4393 if (GET_CODE (insn) == CODE_LABEL)
4395 if (GET_CODE (insn) != NOTE
4396 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4399 insn = PREV_INSN (insn);
4400 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4402 /* If insn is zero, then there must have been a syntax error. */
4406 locus.file = NOTE_SOURCE_FILE (insn);
4407 locus.line = NOTE_LINE_NUMBER (insn);
4408 warning ("%Hunreachable code at beginning of %s", &locus,
4409 case_stack->data.case_stmt.printname);
4417 /* Accumulate one case or default label inside a case or switch statement.
4418 VALUE is the value of the case (a null pointer, for a default label).
4419 The function CONVERTER, when applied to arguments T and V,
4420 converts the value V to the type T.
4422 If not currently inside a case or switch statement, return 1 and do
4423 nothing. The caller will print a language-specific error message.
4424 If VALUE is a duplicate or overlaps, return 2 and do nothing
4425 except store the (first) duplicate node in *DUPLICATE.
4426 If VALUE is out of range, return 3 and do nothing.
4427 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4428 Return 0 on success.
4430 Extended to handle range statements. */
4433 pushcase (tree value, tree (*converter) (tree, tree), tree label,
4439 /* Fail if not inside a real case statement. */
4440 if (! (case_stack && case_stack->data.case_stmt.start))
4443 if (stack_block_stack
4444 && stack_block_stack->depth > case_stack->depth)
4447 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4448 nominal_type = case_stack->data.case_stmt.nominal_type;
4450 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4451 if (index_type == error_mark_node)
4454 /* Convert VALUE to the type in which the comparisons are nominally done. */
4456 value = (*converter) (nominal_type, value);
4460 /* Fail if this value is out of range for the actual type of the index
4461 (which may be narrower than NOMINAL_TYPE). */
4463 && (TREE_CONSTANT_OVERFLOW (value)
4464 || ! int_fits_type_p (value, index_type)))
4467 return add_case_node (value, value, label, duplicate);
4470 /* Like pushcase but this case applies to all values between VALUE1 and
4471 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4472 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4473 starts at VALUE1 and ends at the highest value of the index type.
4474 If both are NULL, this case applies to all values.
4476 The return value is the same as that of pushcase but there is one
4477 additional error code: 4 means the specified range was empty. */
4480 pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree),
4481 tree label, tree *duplicate)
4486 /* Fail if not inside a real case statement. */
4487 if (! (case_stack && case_stack->data.case_stmt.start))
4490 if (stack_block_stack
4491 && stack_block_stack->depth > case_stack->depth)
4494 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4495 nominal_type = case_stack->data.case_stmt.nominal_type;
4497 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4498 if (index_type == error_mark_node)
4503 /* Convert VALUEs to type in which the comparisons are nominally done
4504 and replace any unspecified value with the corresponding bound. */
4506 value1 = TYPE_MIN_VALUE (index_type);
4508 value2 = TYPE_MAX_VALUE (index_type);
4510 /* Fail if the range is empty. Do this before any conversion since
4511 we want to allow out-of-range empty ranges. */
4512 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4515 /* If the max was unbounded, use the max of the nominal_type we are
4516 converting to. Do this after the < check above to suppress false
4519 value2 = TYPE_MAX_VALUE (nominal_type);
4521 value1 = (*converter) (nominal_type, value1);
4522 value2 = (*converter) (nominal_type, value2);
4524 /* Fail if these values are out of range. */
4525 if (TREE_CONSTANT_OVERFLOW (value1)
4526 || ! int_fits_type_p (value1, index_type))
4529 if (TREE_CONSTANT_OVERFLOW (value2)
4530 || ! int_fits_type_p (value2, index_type))
4533 return add_case_node (value1, value2, label, duplicate);
4536 /* Do the actual insertion of a case label for pushcase and pushcase_range
4537 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4538 slowdown for large switch statements. */
4541 add_case_node (tree low, tree high, tree label, tree *duplicate)
4543 struct case_node *p, **q, *r;
4545 /* If there's no HIGH value, then this is not a case range; it's
4546 just a simple case label. But that's just a degenerate case
4551 /* Handle default labels specially. */
4554 if (case_stack->data.case_stmt.default_label != 0)
4556 *duplicate = case_stack->data.case_stmt.default_label;
4559 case_stack->data.case_stmt.default_label = label;
4560 expand_label (label);
4564 q = &case_stack->data.case_stmt.case_list;
4571 /* Keep going past elements distinctly greater than HIGH. */
4572 if (tree_int_cst_lt (high, p->low))
4575 /* or distinctly less than LOW. */
4576 else if (tree_int_cst_lt (p->high, low))
4581 /* We have an overlap; this is an error. */
4582 *duplicate = p->code_label;
4587 /* Add this label to the chain, and succeed. */
4589 r = ggc_alloc (sizeof (struct case_node));
4592 /* If the bounds are equal, turn this into the one-value case. */
4593 if (tree_int_cst_equal (low, high))
4598 r->code_label = label;
4599 expand_label (label);
4609 struct case_node *s;
4615 if (! (b = p->balance))
4616 /* Growth propagation from left side. */
4623 if ((p->left = s = r->right))
4632 if ((r->parent = s))
4640 case_stack->data.case_stmt.case_list = r;
4643 /* r->balance == +1 */
4648 struct case_node *t = r->right;
4650 if ((p->left = s = t->right))
4654 if ((r->right = s = t->left))
4668 if ((t->parent = s))
4676 case_stack->data.case_stmt.case_list = t;
4683 /* p->balance == +1; growth of left side balances the node. */
4693 if (! (b = p->balance))
4694 /* Growth propagation from right side. */
4702 if ((p->right = s = r->left))
4710 if ((r->parent = s))
4719 case_stack->data.case_stmt.case_list = r;
4723 /* r->balance == -1 */
4727 struct case_node *t = r->left;
4729 if ((p->right = s = t->left))
4734 if ((r->left = s = t->right))
4748 if ((t->parent = s))
4757 case_stack->data.case_stmt.case_list = t;
4763 /* p->balance == -1; growth of right side balances the node. */
4776 /* Returns the number of possible values of TYPE.
4777 Returns -1 if the number is unknown, variable, or if the number does not
4778 fit in a HOST_WIDE_INT.
4779 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4780 do not increase monotonically (there may be duplicates);
4781 to 1 if the values increase monotonically, but not always by 1;
4782 otherwise sets it to 0. */
4785 all_cases_count (tree type, int *sparseness)
4788 HOST_WIDE_INT count, minval, lastval;
4792 switch (TREE_CODE (type))
4799 count = 1 << BITS_PER_UNIT;
4804 if (TYPE_MAX_VALUE (type) != 0
4805 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4806 TYPE_MIN_VALUE (type))))
4807 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4808 convert (type, integer_zero_node))))
4809 && host_integerp (t, 1))
4810 count = tree_low_cst (t, 1);
4816 /* Don't waste time with enumeral types with huge values. */
4817 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4818 || TYPE_MAX_VALUE (type) == 0
4819 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4822 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4825 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4827 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4829 if (*sparseness == 2 || thisval <= lastval)
4831 else if (thisval != minval + count)
4842 #define BITARRAY_TEST(ARRAY, INDEX) \
4843 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4844 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4845 #define BITARRAY_SET(ARRAY, INDEX) \
4846 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4847 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4849 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4850 with the case values we have seen, assuming the case expression
4852 SPARSENESS is as determined by all_cases_count.
4854 The time needed is proportional to COUNT, unless
4855 SPARSENESS is 2, in which case quadratic time is needed. */
4858 mark_seen_cases (tree type, unsigned char *cases_seen, HOST_WIDE_INT count,
4861 tree next_node_to_try = NULL_TREE;
4862 HOST_WIDE_INT next_node_offset = 0;
4864 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4865 tree val = make_node (INTEGER_CST);
4867 TREE_TYPE (val) = type;
4871 else if (sparseness == 2)
4874 unsigned HOST_WIDE_INT xlo;
4876 /* This less efficient loop is only needed to handle
4877 duplicate case values (multiple enum constants
4878 with the same value). */
4879 TREE_TYPE (val) = TREE_TYPE (root->low);
4880 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4881 t = TREE_CHAIN (t), xlo++)
4883 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4884 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4888 /* Keep going past elements distinctly greater than VAL. */
4889 if (tree_int_cst_lt (val, n->low))
4892 /* or distinctly less than VAL. */
4893 else if (tree_int_cst_lt (n->high, val))
4898 /* We have found a matching range. */
4899 BITARRAY_SET (cases_seen, xlo);
4909 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
4911 for (n = root; n; n = n->right)
4913 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4914 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4915 while (! tree_int_cst_lt (n->high, val))
4917 /* Calculate (into xlo) the "offset" of the integer (val).
4918 The element with lowest value has offset 0, the next smallest
4919 element has offset 1, etc. */
4921 unsigned HOST_WIDE_INT xlo;
4925 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4927 /* The TYPE_VALUES will be in increasing order, so
4928 starting searching where we last ended. */
4929 t = next_node_to_try;
4930 xlo = next_node_offset;
4936 t = TYPE_VALUES (type);
4939 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4941 next_node_to_try = TREE_CHAIN (t);
4942 next_node_offset = xlo + 1;
4947 if (t == next_node_to_try)
4956 t = TYPE_MIN_VALUE (type);
4958 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
4962 add_double (xlo, xhi,
4963 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4967 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
4968 BITARRAY_SET (cases_seen, xlo);
4970 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4972 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
4978 /* Given a switch statement with an expression that is an enumeration
4979 type, warn if any of the enumeration type's literals are not
4980 covered by the case expressions of the switch. Also, warn if there
4981 are any extra switch cases that are *not* elements of the
4986 At one stage this function would: ``If all enumeration literals
4987 were covered by the case expressions, turn one of the expressions
4988 into the default expression since it should not be possible to fall
4989 through such a switch.''
4991 That code has since been removed as: ``This optimization is
4992 disabled because it causes valid programs to fail. ANSI C does not
4993 guarantee that an expression with enum type will have a value that
4994 is the same as one of the enumeration literals.'' */
4997 check_for_full_enumeration_handling (tree type)
4999 struct case_node *n;
5002 /* True iff the selector type is a numbered set mode. */
5005 /* The number of possible selector values. */
5008 /* For each possible selector value. a one iff it has been matched
5009 by a case value alternative. */
5010 unsigned char *cases_seen;
5012 /* The allocated size of cases_seen, in chars. */
5013 HOST_WIDE_INT bytes_needed;
5015 size = all_cases_count (type, &sparseness);
5016 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5018 if (size > 0 && size < 600000
5019 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5020 this optimization if we don't have enough memory rather than
5021 aborting, as xmalloc would do. */
5022 && (cases_seen = really_call_calloc (bytes_needed, 1)) != NULL)
5025 tree v = TYPE_VALUES (type);
5027 /* The time complexity of this code is normally O(N), where
5028 N being the number of members in the enumerated type.
5029 However, if type is an ENUMERAL_TYPE whose values do not
5030 increase monotonically, O(N*log(N)) time may be needed. */
5032 mark_seen_cases (type, cases_seen, size, sparseness);
5034 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5035 if (BITARRAY_TEST (cases_seen, i) == 0)
5036 warning ("enumeration value `%s' not handled in switch",
5037 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5042 /* Now we go the other way around; we warn if there are case
5043 expressions that don't correspond to enumerators. This can
5044 occur since C and C++ don't enforce type-checking of
5045 assignments to enumeration variables. */
5047 if (case_stack->data.case_stmt.case_list
5048 && case_stack->data.case_stmt.case_list->left)
5049 case_stack->data.case_stmt.case_list
5050 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5051 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5053 for (chain = TYPE_VALUES (type);
5054 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5055 chain = TREE_CHAIN (chain))
5060 if (TYPE_NAME (type) == 0)
5061 warning ("case value `%ld' not in enumerated type",
5062 (long) TREE_INT_CST_LOW (n->low));
5064 warning ("case value `%ld' not in enumerated type `%s'",
5065 (long) TREE_INT_CST_LOW (n->low),
5066 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5069 : DECL_NAME (TYPE_NAME (type))));
5071 if (!tree_int_cst_equal (n->low, n->high))
5073 for (chain = TYPE_VALUES (type);
5074 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5075 chain = TREE_CHAIN (chain))
5080 if (TYPE_NAME (type) == 0)
5081 warning ("case value `%ld' not in enumerated type",
5082 (long) TREE_INT_CST_LOW (n->high));
5084 warning ("case value `%ld' not in enumerated type `%s'",
5085 (long) TREE_INT_CST_LOW (n->high),
5086 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5089 : DECL_NAME (TYPE_NAME (type))));
5096 /* Maximum number of case bit tests. */
5097 #define MAX_CASE_BIT_TESTS 3
5099 /* By default, enable case bit tests on targets with ashlsi3. */
5100 #ifndef CASE_USE_BIT_TESTS
5101 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5102 != CODE_FOR_nothing)
5106 /* A case_bit_test represents a set of case nodes that may be
5107 selected from using a bit-wise comparison. HI and LO hold
5108 the integer to be tested against, LABEL contains the label
5109 to jump to upon success and BITS counts the number of case
5110 nodes handled by this test, typically the number of bits
5113 struct case_bit_test
5121 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5124 bool lshift_cheap_p (void)
5126 static bool init = false;
5127 static bool cheap = true;
5131 rtx reg = gen_rtx_REG (word_mode, 10000);
5132 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5133 cheap = cost < COSTS_N_INSNS (3);
5140 /* Comparison function for qsort to order bit tests by decreasing
5141 number of case nodes, i.e. the node with the most cases gets
5145 int case_bit_test_cmp (const void *p1, const void *p2)
5147 const struct case_bit_test *d1 = p1;
5148 const struct case_bit_test *d2 = p2;
5150 return d2->bits - d1->bits;
5153 /* Expand a switch statement by a short sequence of bit-wise
5154 comparisons. "switch(x)" is effectively converted into
5155 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5158 INDEX_EXPR is the value being switched on, which is of
5159 type INDEX_TYPE. MINVAL is the lowest case value of in
5160 the case nodes, of INDEX_TYPE type, and RANGE is highest
5161 value minus MINVAL, also of type INDEX_TYPE. NODES is
5162 the set of case nodes, and DEFAULT_LABEL is the label to
5163 branch to should none of the cases match.
5165 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5169 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
5170 tree range, case_node_ptr nodes, rtx default_label)
5172 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5173 enum machine_mode mode;
5174 rtx expr, index, label;
5175 unsigned int i,j,lo,hi;
5176 struct case_node *n;
5180 for (n = nodes; n; n = n->right)
5182 label = label_rtx (n->code_label);
5183 for (i = 0; i < count; i++)
5184 if (same_case_target_p (label, test[i].label))
5189 if (count >= MAX_CASE_BIT_TESTS)
5193 test[i].label = label;
5200 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5201 n->low, minval)), 1);
5202 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5203 n->high, minval)), 1);
5204 for (j = lo; j <= hi; j++)
5205 if (j >= HOST_BITS_PER_WIDE_INT)
5206 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5208 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5211 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5213 index_expr = fold (build (MINUS_EXPR, index_type,
5214 convert (index_type, index_expr),
5215 convert (index_type, minval)));
5216 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5218 index = protect_from_queue (index, 0);
5219 do_pending_stack_adjust ();
5221 mode = TYPE_MODE (index_type);
5222 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5223 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5226 index = convert_to_mode (word_mode, index, 0);
5227 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5228 index, NULL_RTX, 1, OPTAB_WIDEN);
5230 for (i = 0; i < count; i++)
5232 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5233 expr = expand_binop (word_mode, and_optab, index, expr,
5234 NULL_RTX, 1, OPTAB_WIDEN);
5235 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5236 word_mode, 1, test[i].label);
5239 emit_jump (default_label);
5242 /* Terminate a case (Pascal) or switch (C) statement
5243 in which ORIG_INDEX is the expression to be tested.
5244 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5245 type as given in the source before any compiler conversions.
5246 Generate the code to test it and jump to the right place. */
5249 expand_end_case_type (tree orig_index, tree orig_type)
5251 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5252 rtx default_label = 0;
5253 struct case_node *n, *m;
5254 unsigned int count, uniq;
5260 rtx before_case, end, lab;
5261 struct nesting *thiscase = case_stack;
5262 tree index_expr, index_type;
5263 bool exit_done = false;
5266 /* Don't crash due to previous errors. */
5267 if (thiscase == NULL)
5270 index_expr = thiscase->data.case_stmt.index_expr;
5271 index_type = TREE_TYPE (index_expr);
5272 unsignedp = TREE_UNSIGNED (index_type);
5273 if (orig_type == NULL)
5274 orig_type = TREE_TYPE (orig_index);
5276 do_pending_stack_adjust ();
5278 /* This might get a spurious warning in the presence of a syntax error;
5279 it could be fixed by moving the call to check_seenlabel after the
5280 check for error_mark_node, and copying the code of check_seenlabel that
5281 deals with case_stack->data.case_stmt.line_number_status /
5282 restore_line_number_status in front of the call to end_cleanup_deferral;
5283 However, this might miss some useful warnings in the presence of
5284 non-syntax errors. */
5287 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5288 if (index_type != error_mark_node)
5290 /* If the switch expression was an enumerated type, check that
5291 exactly all enumeration literals are covered by the cases.
5292 The check is made when -Wswitch was specified and there is no
5293 default case, or when -Wswitch-enum was specified. */
5294 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5295 || warn_switch_enum)
5296 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5297 && TREE_CODE (index_expr) != INTEGER_CST)
5298 check_for_full_enumeration_handling (orig_type);
5300 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5301 warning ("switch missing default case");
5303 /* If we don't have a default-label, create one here,
5304 after the body of the switch. */
5305 if (thiscase->data.case_stmt.default_label == 0)
5307 thiscase->data.case_stmt.default_label
5308 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5309 /* Share the exit label if possible. */
5310 if (thiscase->exit_label)
5312 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5313 thiscase->exit_label);
5316 expand_label (thiscase->data.case_stmt.default_label);
5318 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5320 before_case = get_last_insn ();
5322 if (thiscase->data.case_stmt.case_list
5323 && thiscase->data.case_stmt.case_list->left)
5324 thiscase->data.case_stmt.case_list
5325 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5327 /* Simplify the case-list before we count it. */
5328 group_case_nodes (thiscase->data.case_stmt.case_list);
5329 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5332 /* Get upper and lower bounds of case values.
5333 Also convert all the case values to the index expr's data type. */
5337 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5339 /* Check low and high label values are integers. */
5340 if (TREE_CODE (n->low) != INTEGER_CST)
5342 if (TREE_CODE (n->high) != INTEGER_CST)
5345 n->low = convert (index_type, n->low);
5346 n->high = convert (index_type, n->high);
5348 /* Count the elements and track the largest and smallest
5349 of them (treating them as signed even if they are not). */
5357 if (INT_CST_LT (n->low, minval))
5359 if (INT_CST_LT (maxval, n->high))
5362 /* A range counts double, since it requires two compares. */
5363 if (! tree_int_cst_equal (n->low, n->high))
5366 /* Count the number of unique case node targets. */
5368 lab = label_rtx (n->code_label);
5369 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5370 if (same_case_target_p (label_rtx (m->code_label), lab))
5377 /* Compute span of values. */
5379 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5381 end_cleanup_deferral ();
5385 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5387 emit_jump (default_label);
5390 /* Try implementing this switch statement by a short sequence of
5391 bit-wise comparisons. However, we let the binary-tree case
5392 below handle constant index expressions. */
5393 else if (CASE_USE_BIT_TESTS
5394 && ! TREE_CONSTANT (index_expr)
5395 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5396 && compare_tree_int (range, 0) > 0
5397 && lshift_cheap_p ()
5398 && ((uniq == 1 && count >= 3)
5399 || (uniq == 2 && count >= 5)
5400 || (uniq == 3 && count >= 6)))
5402 /* Optimize the case where all the case values fit in a
5403 word without having to subtract MINVAL. In this case,
5404 we can optimize away the subtraction. */
5405 if (compare_tree_int (minval, 0) > 0
5406 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5408 minval = integer_zero_node;
5411 emit_case_bit_tests (index_type, index_expr, minval, range,
5412 thiscase->data.case_stmt.case_list,
5416 /* If range of values is much bigger than number of values,
5417 make a sequence of conditional branches instead of a dispatch.
5418 If the switch-index is a constant, do it this way
5419 because we can optimize it. */
5421 else if (count < case_values_threshold ()
5422 || compare_tree_int (range, 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"