1 /* Expands front end tree to back end RTL for GCC
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
22 /* This file handles the generation of rtl code from tree structure
23 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
24 It also creates the rtl expressions for parameters and auto variables
25 and has full responsibility for allocating stack slots.
27 The functions whose names start with `expand_' are called by the
28 parser to generate RTL instructions for various kinds of constructs.
30 Some control and binding constructs require calling several such
31 functions at different times. For example, a simple if-then
32 is expanded by calling `expand_start_cond' (with the condition-expression
33 as argument) before parsing the then-clause and calling `expand_end_cond'
34 after parsing the then-clause. */
38 #include "coretypes.h"
47 #include "insn-config.h"
50 #include "hard-reg-set.h"
57 #include "langhooks.h"
62 /* Assume that case vectors are not pc-relative. */
63 #ifndef CASE_VECTOR_PC_RELATIVE
64 #define CASE_VECTOR_PC_RELATIVE 0
67 /* Functions and data structures for expanding case statements. */
69 /* Case label structure, used to hold info on labels within case
70 statements. We handle "range" labels; for a single-value label
71 as in C, the high and low limits are the same.
73 An AVL tree of case nodes is initially created, and later transformed
74 to a list linked via the RIGHT fields in the nodes. Nodes with
75 higher case values are later in the list.
77 Switch statements can be output in one of two forms. A branch table
78 is used if there are more than a few labels and the labels are dense
79 within the range between the smallest and largest case value. If a
80 branch table is used, no further manipulations are done with the case
83 The alternative to the use of a branch table is to generate a series
84 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
85 and PARENT fields to hold a binary tree. Initially the tree is
86 totally unbalanced, with everything on the right. We balance the tree
87 with nodes on the left having lower case values than the parent
88 and nodes on the right having higher values. We then output the tree
91 struct case_node GTY(())
93 struct case_node *left; /* Left son in binary tree */
94 struct case_node *right; /* Right son in binary tree; also node chain */
95 struct case_node *parent; /* Parent of node in binary tree */
96 tree low; /* Lowest index value for this label */
97 tree high; /* Highest index value for this label */
98 tree code_label; /* Label to jump to when node matches */
102 typedef struct case_node case_node;
103 typedef struct case_node *case_node_ptr;
105 /* These are used by estimate_case_costs and balance_case_nodes. */
107 /* This must be a signed type, and non-ANSI compilers lack signed char. */
108 static short cost_table_[129];
109 static int use_cost_table;
110 static int cost_table_initialized;
112 /* Special care is needed because we allow -1, but TREE_INT_CST_LOW
114 #define COST_TABLE(I) cost_table_[(unsigned HOST_WIDE_INT) ((I) + 1)]
116 /* Stack of control and binding constructs we are currently inside.
118 These constructs begin when you call `expand_start_WHATEVER'
119 and end when you call `expand_end_WHATEVER'. This stack records
120 info about how the construct began that tells the end-function
121 what to do. It also may provide information about the construct
122 to alter the behavior of other constructs within the body.
123 For example, they may affect the behavior of C `break' and `continue'.
125 Each construct gets one `struct nesting' object.
126 All of these objects are chained through the `all' field.
127 `nesting_stack' points to the first object (innermost construct).
128 The position of an entry on `nesting_stack' is in its `depth' field.
130 Each type of construct has its own individual stack.
131 For example, loops have `loop_stack'. Each object points to the
132 next object of the same type through the `next' field.
134 Some constructs are visible to `break' exit-statements and others
135 are not. Which constructs are visible depends on the language.
136 Therefore, the data structure allows each construct to be visible
137 or not, according to the args given when the construct is started.
138 The construct is visible if the `exit_label' field is non-null.
139 In that case, the value should be a CODE_LABEL rtx. */
141 struct nesting GTY(())
144 struct nesting *next;
155 /* For conds (if-then and if-then-else statements). */
158 /* Label for the end of the if construct.
159 There is none if EXITFLAG was not set
160 and no `else' has been seen yet. */
162 /* Label for the end of this alternative.
163 This may be the end of the if or the next else/elseif. */
165 } GTY ((tag ("COND_NESTING"))) cond;
169 /* Label at the top of the loop; place to loop back to. */
171 /* Label at the end of the whole construct. */
173 /* Label for `continue' statement to jump to;
174 this is in front of the stepper of the loop. */
176 } GTY ((tag ("LOOP_NESTING"))) loop;
177 /* For variable binding contours. */
180 /* Sequence number of this binding contour within the function,
181 in order of entry. */
182 int block_start_count;
183 /* Nonzero => value to restore stack to on exit. */
185 /* The NOTE that starts this contour.
186 Used by expand_goto to check whether the destination
187 is within each contour or not. */
189 /* Innermost containing binding contour that has a stack level. */
190 struct nesting *innermost_stack_block;
191 /* List of cleanups to be run on exit from this contour.
192 This is a list of expressions to be evaluated.
193 The TREE_PURPOSE of each link is the ..._DECL node
194 which the cleanup pertains to. */
196 /* List of cleanup-lists of blocks containing this block,
197 as they were at the locus where this block appears.
198 There is an element for each containing block,
199 ordered innermost containing block first.
200 The tail of this list can be 0,
201 if all remaining elements would be empty lists.
202 The element's TREE_VALUE is the cleanup-list of that block,
203 which may be null. */
205 /* Chain of labels defined inside this binding contour.
206 For contours that have stack levels or cleanups. */
207 struct label_chain *label_chain;
208 /* Nonzero if this is associated with an EH region. */
209 int exception_region;
210 /* The saved target_temp_slot_level from our outer block.
211 We may reset target_temp_slot_level to be the level of
212 this block, if that is done, target_temp_slot_level
213 reverts to the saved target_temp_slot_level at the very
215 int block_target_temp_slot_level;
216 /* True if we are currently emitting insns in an area of
217 output code that is controlled by a conditional
218 expression. This is used by the cleanup handling code to
219 generate conditional cleanup actions. */
220 int conditional_code;
221 /* A place to move the start of the exception region for any
222 of the conditional cleanups, must be at the end or after
223 the start of the last unconditional cleanup, and before any
224 conditional branch points. */
225 rtx last_unconditional_cleanup;
226 } GTY ((tag ("BLOCK_NESTING"))) block;
227 /* For switch (C) or case (Pascal) statements,
228 and also for dummies (see `expand_start_case_dummy'). */
231 /* The insn after which the case dispatch should finally
232 be emitted. Zero for a dummy. */
234 /* A list of case labels; it is first built as an AVL tree.
235 During expand_end_case, this is converted to a list, and may be
236 rearranged into a nearly balanced binary tree. */
237 struct case_node *case_list;
238 /* Label to jump to if no case matches. */
240 /* The expression to be dispatched on. */
242 /* Type that INDEX_EXPR should be converted to. */
244 /* Name of this kind of statement, for warnings. */
245 const char *printname;
246 /* Used to save no_line_numbers till we see the first case label.
247 We set this to -1 when we see the first case label in this
249 int line_number_status;
250 } GTY ((tag ("CASE_NESTING"))) case_stmt;
251 } GTY ((desc ("%1.desc"))) data;
254 /* Allocate and return a new `struct nesting'. */
256 #define ALLOC_NESTING() ggc_alloc (sizeof (struct nesting))
258 /* Pop the nesting stack element by element until we pop off
259 the element which is at the top of STACK.
260 Update all the other stacks, popping off elements from them
261 as we pop them from nesting_stack. */
263 #define POPSTACK(STACK) \
264 do { struct nesting *target = STACK; \
265 struct nesting *this; \
266 do { this = nesting_stack; \
267 if (loop_stack == this) \
268 loop_stack = loop_stack->next; \
269 if (cond_stack == this) \
270 cond_stack = cond_stack->next; \
271 if (block_stack == this) \
272 block_stack = block_stack->next; \
273 if (stack_block_stack == this) \
274 stack_block_stack = stack_block_stack->next; \
275 if (case_stack == this) \
276 case_stack = case_stack->next; \
277 nesting_depth = nesting_stack->depth - 1; \
278 nesting_stack = this->all; } \
279 while (this != target); } while (0)
281 /* In some cases it is impossible to generate code for a forward goto
282 until the label definition is seen. This happens when it may be necessary
283 for the goto to reset the stack pointer: we don't yet know how to do that.
284 So expand_goto puts an entry on this fixup list.
285 Each time a binding contour that resets the stack is exited,
287 If the target label has now been defined, we can insert the proper code. */
289 struct goto_fixup GTY(())
291 /* Points to following fixup. */
292 struct goto_fixup *next;
293 /* Points to the insn before the jump insn.
294 If more code must be inserted, it goes after this insn. */
296 /* The LABEL_DECL that this jump is jumping to, or 0
297 for break, continue or return. */
299 /* The BLOCK for the place where this goto was found. */
301 /* The CODE_LABEL rtx that this is jumping to. */
303 /* Number of binding contours started in current function
304 before the label reference. */
305 int block_start_count;
306 /* The outermost stack level that should be restored for this jump.
307 Each time a binding contour that resets the stack is exited,
308 if the target label is *not* yet defined, this slot is updated. */
310 /* List of lists of cleanup expressions to be run by this goto.
311 There is one element for each block that this goto is within.
312 The tail of this list can be 0,
313 if all remaining elements would be empty.
314 The TREE_VALUE contains the cleanup list of that block as of the
315 time this goto was seen.
316 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
317 tree cleanup_list_list;
320 /* Within any binding contour that must restore a stack level,
321 all labels are recorded with a chain of these structures. */
323 struct label_chain GTY(())
325 /* Points to following fixup. */
326 struct label_chain *next;
330 struct stmt_status GTY(())
332 /* Chain of all pending binding contours. */
333 struct nesting * x_block_stack;
335 /* If any new stacks are added here, add them to POPSTACKS too. */
337 /* Chain of all pending binding contours that restore stack levels
339 struct nesting * x_stack_block_stack;
341 /* Chain of all pending conditional statements. */
342 struct nesting * x_cond_stack;
344 /* Chain of all pending loops. */
345 struct nesting * x_loop_stack;
347 /* Chain of all pending case or switch statements. */
348 struct nesting * x_case_stack;
350 /* Separate chain including all of the above,
351 chained through the `all' field. */
352 struct nesting * x_nesting_stack;
354 /* Number of entries on nesting_stack now. */
357 /* Number of binding contours started so far in this function. */
358 int x_block_start_count;
360 /* Each time we expand an expression-statement,
361 record the expr's type and its RTL value here. */
362 tree x_last_expr_type;
363 rtx x_last_expr_value;
364 rtx x_last_expr_alt_rtl;
366 /* Nonzero if within a ({...}) grouping, in which case we must
367 always compute a value for each expr-stmt in case it is the last one. */
368 int x_expr_stmts_for_value;
370 /* Location of last line-number note, whether we actually
371 emitted it or not. */
372 location_t x_emit_locus;
374 struct goto_fixup *x_goto_fixup_chain;
377 #define block_stack (cfun->stmt->x_block_stack)
378 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
379 #define cond_stack (cfun->stmt->x_cond_stack)
380 #define loop_stack (cfun->stmt->x_loop_stack)
381 #define case_stack (cfun->stmt->x_case_stack)
382 #define nesting_stack (cfun->stmt->x_nesting_stack)
383 #define nesting_depth (cfun->stmt->x_nesting_depth)
384 #define current_block_start_count (cfun->stmt->x_block_start_count)
385 #define last_expr_type (cfun->stmt->x_last_expr_type)
386 #define last_expr_value (cfun->stmt->x_last_expr_value)
387 #define last_expr_alt_rtl (cfun->stmt->x_last_expr_alt_rtl)
388 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
389 #define emit_locus (cfun->stmt->x_emit_locus)
390 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
392 /* Nonzero if we are using EH to handle cleanups. */
393 static int using_eh_for_cleanups_p = 0;
395 static int n_occurrences (int, const char *);
396 static bool decl_conflicts_with_clobbers_p (tree, const HARD_REG_SET);
397 static void expand_goto_internal (tree, rtx, rtx);
398 static int expand_fixup (tree, rtx, rtx);
399 static rtx expand_nl_handler_label (rtx, rtx);
400 static void expand_nl_goto_receiver (void);
401 static void expand_nl_goto_receivers (struct nesting *);
402 static void fixup_gotos (struct nesting *, rtx, tree, rtx, int);
403 static bool check_operand_nalternatives (tree, tree);
404 static bool check_unique_operand_names (tree, tree);
405 static char *resolve_operand_name_1 (char *, tree, tree);
406 static void expand_null_return_1 (rtx);
407 static enum br_predictor return_prediction (rtx);
408 static rtx shift_return_value (rtx);
409 static void expand_value_return (rtx);
410 static int tail_recursion_args (tree, tree);
411 static void expand_cleanups (tree, int, int);
412 static void check_seenlabel (void);
413 static void do_jump_if_equal (rtx, rtx, rtx, int);
414 static int estimate_case_costs (case_node_ptr);
415 static bool same_case_target_p (rtx, rtx);
416 static void strip_default_case_nodes (case_node_ptr *, rtx);
417 static bool lshift_cheap_p (void);
418 static int case_bit_test_cmp (const void *, const void *);
419 static void emit_case_bit_tests (tree, tree, tree, tree, case_node_ptr, rtx);
420 static void group_case_nodes (case_node_ptr);
421 static void balance_case_nodes (case_node_ptr *, case_node_ptr);
422 static int node_has_low_bound (case_node_ptr, tree);
423 static int node_has_high_bound (case_node_ptr, tree);
424 static int node_is_bounded (case_node_ptr, tree);
425 static void emit_jump_if_reachable (rtx);
426 static void emit_case_nodes (rtx, case_node_ptr, rtx, tree);
427 static struct case_node *case_tree2list (case_node *, case_node *);
430 using_eh_for_cleanups (void)
432 using_eh_for_cleanups_p = 1;
436 init_stmt_for_function (void)
438 cfun->stmt = ggc_alloc_cleared (sizeof (struct stmt_status));
441 /* Record the current file and line. Called from emit_line_note. */
444 set_file_and_line_for_stmt (location_t location)
446 /* If we're outputting an inline function, and we add a line note,
447 there may be no CFUN->STMT information. So, there's no need to
450 emit_locus = location;
453 /* Emit a no-op instruction. */
460 last_insn = get_last_insn ();
462 && (GET_CODE (last_insn) == CODE_LABEL
463 || (GET_CODE (last_insn) == NOTE
464 && prev_real_insn (last_insn) == 0)))
465 emit_insn (gen_nop ());
468 /* Return the rtx-label that corresponds to a LABEL_DECL,
469 creating it if necessary. */
472 label_rtx (tree label)
474 if (TREE_CODE (label) != LABEL_DECL)
477 if (!DECL_RTL_SET_P (label))
478 SET_DECL_RTL (label, gen_label_rtx ());
480 return DECL_RTL (label);
483 /* As above, but also put it on the forced-reference list of the
484 function that contains it. */
486 force_label_rtx (tree label)
488 rtx ref = label_rtx (label);
489 tree function = decl_function_context (label);
495 if (function != current_function_decl
496 && function != inline_function_decl)
497 p = find_function_data (function);
501 p->expr->x_forced_labels = gen_rtx_EXPR_LIST (VOIDmode, ref,
502 p->expr->x_forced_labels);
506 /* Add an unconditional jump to LABEL as the next sequential instruction. */
509 emit_jump (rtx label)
511 do_pending_stack_adjust ();
512 emit_jump_insn (gen_jump (label));
516 /* Emit code to jump to the address
517 specified by the pointer expression EXP. */
520 expand_computed_goto (tree exp)
522 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
524 x = convert_memory_address (Pmode, x);
528 if (! cfun->computed_goto_common_label)
530 cfun->computed_goto_common_reg = copy_to_mode_reg (Pmode, x);
531 cfun->computed_goto_common_label = gen_label_rtx ();
533 do_pending_stack_adjust ();
534 emit_label (cfun->computed_goto_common_label);
535 emit_indirect_jump (cfun->computed_goto_common_reg);
537 current_function_has_computed_jump = 1;
541 emit_move_insn (cfun->computed_goto_common_reg, x);
542 emit_jump (cfun->computed_goto_common_label);
546 /* Handle goto statements and the labels that they can go to. */
548 /* Specify the location in the RTL code of a label LABEL,
549 which is a LABEL_DECL tree node.
551 This is used for the kind of label that the user can jump to with a
552 goto statement, and for alternatives of a switch or case statement.
553 RTL labels generated for loops and conditionals don't go through here;
554 they are generated directly at the RTL level, by other functions below.
556 Note that this has nothing to do with defining label *names*.
557 Languages vary in how they do that and what that even means. */
560 expand_label (tree label)
562 struct label_chain *p;
564 do_pending_stack_adjust ();
565 emit_label (label_rtx (label));
566 if (DECL_NAME (label))
567 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
569 if (stack_block_stack != 0)
571 p = ggc_alloc (sizeof (struct label_chain));
572 p->next = stack_block_stack->data.block.label_chain;
573 stack_block_stack->data.block.label_chain = p;
578 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
579 from nested functions. */
582 declare_nonlocal_label (tree label)
584 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
586 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
587 LABEL_PRESERVE_P (label_rtx (label)) = 1;
588 if (nonlocal_goto_handler_slots == 0)
590 emit_stack_save (SAVE_NONLOCAL,
591 &nonlocal_goto_stack_level,
592 PREV_INSN (tail_recursion_reentry));
594 nonlocal_goto_handler_slots
595 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
598 /* Generate RTL code for a `goto' statement with target label LABEL.
599 LABEL should be a LABEL_DECL tree node that was or will later be
600 defined with `expand_label'. */
603 expand_goto (tree label)
607 /* Check for a nonlocal goto to a containing function. */
608 context = decl_function_context (label);
609 if (context != 0 && context != current_function_decl)
611 struct function *p = find_function_data (context);
612 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
613 rtx handler_slot, static_chain, save_area, insn;
616 /* Find the corresponding handler slot for this label. */
617 handler_slot = p->x_nonlocal_goto_handler_slots;
618 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
619 link = TREE_CHAIN (link))
620 handler_slot = XEXP (handler_slot, 1);
621 handler_slot = XEXP (handler_slot, 0);
623 p->has_nonlocal_label = 1;
624 current_function_has_nonlocal_goto = 1;
625 LABEL_REF_NONLOCAL_P (label_ref) = 1;
627 /* Copy the rtl for the slots so that they won't be shared in
628 case the virtual stack vars register gets instantiated differently
629 in the parent than in the child. */
631 static_chain = copy_to_reg (lookup_static_chain (label));
633 /* Get addr of containing function's current nonlocal goto handler,
634 which will do any cleanups and then jump to the label. */
635 handler_slot = copy_to_reg (replace_rtx (copy_rtx (handler_slot),
636 virtual_stack_vars_rtx,
639 /* Get addr of containing function's nonlocal save area. */
640 save_area = p->x_nonlocal_goto_stack_level;
642 save_area = replace_rtx (copy_rtx (save_area),
643 virtual_stack_vars_rtx, static_chain);
645 #if HAVE_nonlocal_goto
646 if (HAVE_nonlocal_goto)
647 emit_insn (gen_nonlocal_goto (static_chain, handler_slot,
648 save_area, label_ref));
652 emit_insn (gen_rtx_CLOBBER (VOIDmode,
653 gen_rtx_MEM (BLKmode,
654 gen_rtx_SCRATCH (VOIDmode))));
655 emit_insn (gen_rtx_CLOBBER (VOIDmode,
656 gen_rtx_MEM (BLKmode,
657 hard_frame_pointer_rtx)));
659 /* Restore frame pointer for containing function.
660 This sets the actual hard register used for the frame pointer
661 to the location of the function's incoming static chain info.
662 The non-local goto handler will then adjust it to contain the
663 proper value and reload the argument pointer, if needed. */
664 emit_move_insn (hard_frame_pointer_rtx, static_chain);
665 emit_stack_restore (SAVE_NONLOCAL, save_area, NULL_RTX);
667 /* USE of hard_frame_pointer_rtx added for consistency;
668 not clear if really needed. */
669 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
670 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
671 emit_indirect_jump (handler_slot);
674 /* Search backwards to the jump insn and mark it as a
676 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
678 if (GET_CODE (insn) == JUMP_INSN)
680 REG_NOTES (insn) = alloc_EXPR_LIST (REG_NON_LOCAL_GOTO,
681 const0_rtx, REG_NOTES (insn));
684 else if (GET_CODE (insn) == CALL_INSN)
689 expand_goto_internal (label, label_rtx (label), NULL_RTX);
692 /* Generate RTL code for a `goto' statement with target label BODY.
693 LABEL should be a LABEL_REF.
694 LAST_INSN, if non-0, is the rtx we should consider as the last
695 insn emitted (for the purposes of cleaning up a return). */
698 expand_goto_internal (tree body, rtx label, rtx last_insn)
700 struct nesting *block;
703 if (GET_CODE (label) != CODE_LABEL)
706 /* If label has already been defined, we can tell now
707 whether and how we must alter the stack level. */
709 if (PREV_INSN (label) != 0)
711 /* Find the innermost pending block that contains the label.
712 (Check containment by comparing insn-uids.)
713 Then restore the outermost stack level within that block,
714 and do cleanups of all blocks contained in it. */
715 for (block = block_stack; block; block = block->next)
717 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
719 if (block->data.block.stack_level != 0)
720 stack_level = block->data.block.stack_level;
721 /* Execute the cleanups for blocks we are exiting. */
722 if (block->data.block.cleanups != 0)
724 expand_cleanups (block->data.block.cleanups, 1, 1);
725 do_pending_stack_adjust ();
731 /* Ensure stack adjust isn't done by emit_jump, as this
732 would clobber the stack pointer. This one should be
733 deleted as dead by flow. */
734 clear_pending_stack_adjust ();
735 do_pending_stack_adjust ();
737 /* Don't do this adjust if it's to the end label and this function
738 is to return with a depressed stack pointer. */
739 if (label == return_label
740 && (((TREE_CODE (TREE_TYPE (current_function_decl))
742 && (TYPE_RETURNS_STACK_DEPRESSED
743 (TREE_TYPE (current_function_decl))))))
746 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
749 if (body != 0 && DECL_TOO_LATE (body))
750 error ("jump to `%s' invalidly jumps into binding contour",
751 IDENTIFIER_POINTER (DECL_NAME (body)));
753 /* Label not yet defined: may need to put this goto
754 on the fixup list. */
755 else if (! expand_fixup (body, label, last_insn))
757 /* No fixup needed. Record that the label is the target
758 of at least one goto that has no fixup. */
760 TREE_ADDRESSABLE (body) = 1;
766 /* Generate if necessary a fixup for a goto
767 whose target label in tree structure (if any) is TREE_LABEL
768 and whose target in rtl is RTL_LABEL.
770 If LAST_INSN is nonzero, we pretend that the jump appears
771 after insn LAST_INSN instead of at the current point in the insn stream.
773 The fixup will be used later to insert insns just before the goto.
774 Those insns will restore the stack level as appropriate for the
775 target label, and will (in the case of C++) also invoke any object
776 destructors which have to be invoked when we exit the scopes which
777 are exited by the goto.
779 Value is nonzero if a fixup is made. */
782 expand_fixup (tree tree_label, rtx rtl_label, rtx last_insn)
784 struct nesting *block, *end_block;
786 /* See if we can recognize which block the label will be output in.
787 This is possible in some very common cases.
788 If we succeed, set END_BLOCK to that block.
789 Otherwise, set it to 0. */
792 && (rtl_label == cond_stack->data.cond.endif_label
793 || rtl_label == cond_stack->data.cond.next_label))
794 end_block = cond_stack;
795 /* If we are in a loop, recognize certain labels which
796 are likely targets. This reduces the number of fixups
797 we need to create. */
799 && (rtl_label == loop_stack->data.loop.start_label
800 || rtl_label == loop_stack->data.loop.end_label
801 || rtl_label == loop_stack->data.loop.continue_label))
802 end_block = loop_stack;
806 /* Now set END_BLOCK to the binding level to which we will return. */
810 struct nesting *next_block = end_block->all;
813 /* First see if the END_BLOCK is inside the innermost binding level.
814 If so, then no cleanups or stack levels are relevant. */
815 while (next_block && next_block != block)
816 next_block = next_block->all;
821 /* Otherwise, set END_BLOCK to the innermost binding level
822 which is outside the relevant control-structure nesting. */
823 next_block = block_stack->next;
824 for (block = block_stack; block != end_block; block = block->all)
825 if (block == next_block)
826 next_block = next_block->next;
827 end_block = next_block;
830 /* Does any containing block have a stack level or cleanups?
831 If not, no fixup is needed, and that is the normal case
832 (the only case, for standard C). */
833 for (block = block_stack; block != end_block; block = block->next)
834 if (block->data.block.stack_level != 0
835 || block->data.block.cleanups != 0)
838 if (block != end_block)
840 /* Ok, a fixup is needed. Add a fixup to the list of such. */
841 struct goto_fixup *fixup = ggc_alloc (sizeof (struct goto_fixup));
842 /* In case an old stack level is restored, make sure that comes
843 after any pending stack adjust. */
844 /* ?? If the fixup isn't to come at the present position,
845 doing the stack adjust here isn't useful. Doing it with our
846 settings at that location isn't useful either. Let's hope
849 do_pending_stack_adjust ();
850 fixup->target = tree_label;
851 fixup->target_rtl = rtl_label;
853 /* Create a BLOCK node and a corresponding matched set of
854 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
855 this point. The notes will encapsulate any and all fixup
856 code which we might later insert at this point in the insn
857 stream. Also, the BLOCK node will be the parent (i.e. the
858 `SUPERBLOCK') of any other BLOCK nodes which we might create
859 later on when we are expanding the fixup code.
861 Note that optimization passes (including expand_end_loop)
862 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
866 rtx original_before_jump
867 = last_insn ? last_insn : get_last_insn ();
872 block = make_node (BLOCK);
873 TREE_USED (block) = 1;
875 if (!cfun->x_whole_function_mode_p)
876 (*lang_hooks.decls.insert_block) (block);
880 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
881 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
886 start = emit_note (NOTE_INSN_BLOCK_BEG);
887 if (cfun->x_whole_function_mode_p)
888 NOTE_BLOCK (start) = block;
889 fixup->before_jump = emit_note (NOTE_INSN_DELETED);
890 end = emit_note (NOTE_INSN_BLOCK_END);
891 if (cfun->x_whole_function_mode_p)
892 NOTE_BLOCK (end) = block;
893 fixup->context = block;
895 emit_insn_after (start, original_before_jump);
898 fixup->block_start_count = current_block_start_count;
899 fixup->stack_level = 0;
900 fixup->cleanup_list_list
901 = ((block->data.block.outer_cleanups
902 || block->data.block.cleanups)
903 ? tree_cons (NULL_TREE, block->data.block.cleanups,
904 block->data.block.outer_cleanups)
906 fixup->next = goto_fixup_chain;
907 goto_fixup_chain = fixup;
913 /* Expand any needed fixups in the outputmost binding level of the
914 function. FIRST_INSN is the first insn in the function. */
917 expand_fixups (rtx first_insn)
919 fixup_gotos (NULL, NULL_RTX, NULL_TREE, first_insn, 0);
922 /* When exiting a binding contour, process all pending gotos requiring fixups.
923 THISBLOCK is the structure that describes the block being exited.
924 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
925 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
926 FIRST_INSN is the insn that began this contour.
928 Gotos that jump out of this contour must restore the
929 stack level and do the cleanups before actually jumping.
931 DONT_JUMP_IN positive means report error if there is a jump into this
932 contour from before the beginning of the contour. This is also done if
933 STACK_LEVEL is nonzero unless DONT_JUMP_IN is negative. */
936 fixup_gotos (struct nesting *thisblock, rtx stack_level,
937 tree cleanup_list, rtx first_insn, int dont_jump_in)
939 struct goto_fixup *f, *prev;
941 /* F is the fixup we are considering; PREV is the previous one. */
942 /* We run this loop in two passes so that cleanups of exited blocks
943 are run first, and blocks that are exited are marked so
946 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
948 /* Test for a fixup that is inactive because it is already handled. */
949 if (f->before_jump == 0)
951 /* Delete inactive fixup from the chain, if that is easy to do. */
953 prev->next = f->next;
955 /* Has this fixup's target label been defined?
956 If so, we can finalize it. */
957 else if (PREV_INSN (f->target_rtl) != 0)
961 /* If this fixup jumped into this contour from before the beginning
962 of this contour, report an error. This code used to use
963 the first non-label insn after f->target_rtl, but that's
964 wrong since such can be added, by things like put_var_into_stack
965 and have INSN_UIDs that are out of the range of the block. */
966 /* ??? Bug: this does not detect jumping in through intermediate
967 blocks that have stack levels or cleanups.
968 It detects only a problem with the innermost block
971 && (dont_jump_in > 0 || (dont_jump_in == 0 && stack_level)
973 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
974 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
975 && ! DECL_ERROR_ISSUED (f->target))
977 error ("%Jlabel '%D' used before containing binding contour",
978 f->target, f->target);
979 /* Prevent multiple errors for one label. */
980 DECL_ERROR_ISSUED (f->target) = 1;
983 /* We will expand the cleanups into a sequence of their own and
984 then later on we will attach this new sequence to the insn
985 stream just ahead of the actual jump insn. */
989 /* Temporarily restore the lexical context where we will
990 logically be inserting the fixup code. We do this for the
991 sake of getting the debugging information right. */
993 (*lang_hooks.decls.pushlevel) (0);
994 (*lang_hooks.decls.set_block) (f->context);
996 /* Expand the cleanups for blocks this jump exits. */
997 if (f->cleanup_list_list)
1000 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1001 /* Marked elements correspond to blocks that have been closed.
1002 Do their cleanups. */
1003 if (TREE_ADDRESSABLE (lists)
1004 && TREE_VALUE (lists) != 0)
1006 expand_cleanups (TREE_VALUE (lists), 1, 1);
1007 /* Pop any pushes done in the cleanups,
1008 in case function is about to return. */
1009 do_pending_stack_adjust ();
1013 /* Restore stack level for the biggest contour that this
1014 jump jumps out of. */
1016 && ! (f->target_rtl == return_label
1017 && ((TREE_CODE (TREE_TYPE (current_function_decl))
1019 && (TYPE_RETURNS_STACK_DEPRESSED
1020 (TREE_TYPE (current_function_decl))))))
1021 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1023 /* Finish up the sequence containing the insns which implement the
1024 necessary cleanups, and then attach that whole sequence to the
1025 insn stream just ahead of the actual jump insn. Attaching it
1026 at that point insures that any cleanups which are in fact
1027 implicit C++ object destructions (which must be executed upon
1028 leaving the block) appear (to the debugger) to be taking place
1029 in an area of the generated code where the object(s) being
1030 destructed are still "in scope". */
1032 cleanup_insns = get_insns ();
1033 (*lang_hooks.decls.poplevel) (1, 0, 0);
1036 emit_insn_after (cleanup_insns, f->before_jump);
1042 /* For any still-undefined labels, do the cleanups for this block now.
1043 We must do this now since items in the cleanup list may go out
1044 of scope when the block ends. */
1045 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1046 if (f->before_jump != 0
1047 && PREV_INSN (f->target_rtl) == 0
1048 /* Label has still not appeared. If we are exiting a block with
1049 a stack level to restore, that started before the fixup,
1050 mark this stack level as needing restoration
1051 when the fixup is later finalized. */
1053 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1054 means the label is undefined. That's erroneous, but possible. */
1055 && (thisblock->data.block.block_start_count
1056 <= f->block_start_count))
1058 tree lists = f->cleanup_list_list;
1061 for (; lists; lists = TREE_CHAIN (lists))
1062 /* If the following elt. corresponds to our containing block
1063 then the elt. must be for this block. */
1064 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1067 (*lang_hooks.decls.pushlevel) (0);
1068 (*lang_hooks.decls.set_block) (f->context);
1069 expand_cleanups (TREE_VALUE (lists), 1, 1);
1070 do_pending_stack_adjust ();
1071 cleanup_insns = get_insns ();
1072 (*lang_hooks.decls.poplevel) (1, 0, 0);
1074 if (cleanup_insns != 0)
1076 = emit_insn_after (cleanup_insns, f->before_jump);
1078 f->cleanup_list_list = TREE_CHAIN (lists);
1082 f->stack_level = stack_level;
1086 /* Return the number of times character C occurs in string S. */
1088 n_occurrences (int c, const char *s)
1096 /* Generate RTL for an asm statement (explicit assembler code).
1097 STRING is a STRING_CST node containing the assembler code text,
1098 or an ADDR_EXPR containing a STRING_CST. VOL nonzero means the
1099 insn is volatile; don't optimize it. */
1102 expand_asm (tree string, int vol)
1106 if (TREE_CODE (string) == ADDR_EXPR)
1107 string = TREE_OPERAND (string, 0);
1109 body = gen_rtx_ASM_INPUT (VOIDmode, TREE_STRING_POINTER (string));
1111 MEM_VOLATILE_P (body) = vol;
1118 /* Parse the output constraint pointed to by *CONSTRAINT_P. It is the
1119 OPERAND_NUMth output operand, indexed from zero. There are NINPUTS
1120 inputs and NOUTPUTS outputs to this extended-asm. Upon return,
1121 *ALLOWS_MEM will be TRUE iff the constraint allows the use of a
1122 memory operand. Similarly, *ALLOWS_REG will be TRUE iff the
1123 constraint allows the use of a register operand. And, *IS_INOUT
1124 will be true if the operand is read-write, i.e., if it is used as
1125 an input as well as an output. If *CONSTRAINT_P is not in
1126 canonical form, it will be made canonical. (Note that `+' will be
1127 replaced with `=' as part of this process.)
1129 Returns TRUE if all went well; FALSE if an error occurred. */
1132 parse_output_constraint (const char **constraint_p, int operand_num,
1133 int ninputs, int noutputs, bool *allows_mem,
1134 bool *allows_reg, bool *is_inout)
1136 const char *constraint = *constraint_p;
1139 /* Assume the constraint doesn't allow the use of either a register
1141 *allows_mem = false;
1142 *allows_reg = false;
1144 /* Allow the `=' or `+' to not be at the beginning of the string,
1145 since it wasn't explicitly documented that way, and there is a
1146 large body of code that puts it last. Swap the character to
1147 the front, so as not to uglify any place else. */
1148 p = strchr (constraint, '=');
1150 p = strchr (constraint, '+');
1152 /* If the string doesn't contain an `=', issue an error
1156 error ("output operand constraint lacks `='");
1160 /* If the constraint begins with `+', then the operand is both read
1161 from and written to. */
1162 *is_inout = (*p == '+');
1164 /* Canonicalize the output constraint so that it begins with `='. */
1165 if (p != constraint || is_inout)
1168 size_t c_len = strlen (constraint);
1170 if (p != constraint)
1171 warning ("output constraint `%c' for operand %d is not at the beginning",
1174 /* Make a copy of the constraint. */
1175 buf = alloca (c_len + 1);
1176 strcpy (buf, constraint);
1177 /* Swap the first character and the `=' or `+'. */
1178 buf[p - constraint] = buf[0];
1179 /* Make sure the first character is an `='. (Until we do this,
1180 it might be a `+'.) */
1182 /* Replace the constraint with the canonicalized string. */
1183 *constraint_p = ggc_alloc_string (buf, c_len);
1184 constraint = *constraint_p;
1187 /* Loop through the constraint string. */
1188 for (p = constraint + 1; *p; p += CONSTRAINT_LEN (*p, p))
1193 error ("operand constraint contains incorrectly positioned '+' or '='");
1197 if (operand_num + 1 == ninputs + noutputs)
1199 error ("`%%' constraint used with last operand");
1204 case 'V': case 'm': case 'o':
1208 case '?': case '!': case '*': case '&': case '#':
1209 case 'E': case 'F': case 'G': case 'H':
1210 case 's': case 'i': case 'n':
1211 case 'I': case 'J': case 'K': case 'L': case 'M':
1212 case 'N': case 'O': case 'P': case ',':
1215 case '0': case '1': case '2': case '3': case '4':
1216 case '5': case '6': case '7': case '8': case '9':
1218 error ("matching constraint not valid in output operand");
1222 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1223 excepting those that expand_call created. So match memory
1240 if (REG_CLASS_FROM_CONSTRAINT (*p, p) != NO_REGS)
1242 #ifdef EXTRA_CONSTRAINT_STR
1243 else if (EXTRA_ADDRESS_CONSTRAINT (*p, p))
1245 else if (EXTRA_MEMORY_CONSTRAINT (*p, p))
1249 /* Otherwise we can't assume anything about the nature of
1250 the constraint except that it isn't purely registers.
1251 Treat it like "g" and hope for the best. */
1262 /* Similar, but for input constraints. */
1265 parse_input_constraint (const char **constraint_p, int input_num,
1266 int ninputs, int noutputs, int ninout,
1267 const char * const * constraints,
1268 bool *allows_mem, bool *allows_reg)
1270 const char *constraint = *constraint_p;
1271 const char *orig_constraint = constraint;
1272 size_t c_len = strlen (constraint);
1274 bool saw_match = false;
1276 /* Assume the constraint doesn't allow the use of either
1277 a register or memory. */
1278 *allows_mem = false;
1279 *allows_reg = false;
1281 /* Make sure constraint has neither `=', `+', nor '&'. */
1283 for (j = 0; j < c_len; j += CONSTRAINT_LEN (constraint[j], constraint+j))
1284 switch (constraint[j])
1286 case '+': case '=': case '&':
1287 if (constraint == orig_constraint)
1289 error ("input operand constraint contains `%c'", constraint[j]);
1295 if (constraint == orig_constraint
1296 && input_num + 1 == ninputs - ninout)
1298 error ("`%%' constraint used with last operand");
1303 case 'V': case 'm': case 'o':
1308 case '?': case '!': case '*': case '#':
1309 case 'E': case 'F': case 'G': case 'H':
1310 case 's': case 'i': case 'n':
1311 case 'I': case 'J': case 'K': case 'L': case 'M':
1312 case 'N': case 'O': case 'P': case ',':
1315 /* Whether or not a numeric constraint allows a register is
1316 decided by the matching constraint, and so there is no need
1317 to do anything special with them. We must handle them in
1318 the default case, so that we don't unnecessarily force
1319 operands to memory. */
1320 case '0': case '1': case '2': case '3': case '4':
1321 case '5': case '6': case '7': case '8': case '9':
1324 unsigned long match;
1328 match = strtoul (constraint + j, &end, 10);
1329 if (match >= (unsigned long) noutputs)
1331 error ("matching constraint references invalid operand number");
1335 /* Try and find the real constraint for this dup. Only do this
1336 if the matching constraint is the only alternative. */
1338 && (j == 0 || (j == 1 && constraint[0] == '%')))
1340 constraint = constraints[match];
1341 *constraint_p = constraint;
1342 c_len = strlen (constraint);
1344 /* ??? At the end of the loop, we will skip the first part of
1345 the matched constraint. This assumes not only that the
1346 other constraint is an output constraint, but also that
1347 the '=' or '+' come first. */
1351 j = end - constraint;
1352 /* Anticipate increment at end of loop. */
1367 if (! ISALPHA (constraint[j]))
1369 error ("invalid punctuation `%c' in constraint", constraint[j]);
1372 if (REG_CLASS_FROM_CONSTRAINT (constraint[j], constraint + j)
1375 #ifdef EXTRA_CONSTRAINT_STR
1376 else if (EXTRA_ADDRESS_CONSTRAINT (constraint[j], constraint + j))
1378 else if (EXTRA_MEMORY_CONSTRAINT (constraint[j], constraint + j))
1382 /* Otherwise we can't assume anything about the nature of
1383 the constraint except that it isn't purely registers.
1384 Treat it like "g" and hope for the best. */
1392 if (saw_match && !*allows_reg)
1393 warning ("matching constraint does not allow a register");
1398 /* Check for overlap between registers marked in CLOBBERED_REGS and
1399 anything inappropriate in DECL. Emit error and return TRUE for error,
1403 decl_conflicts_with_clobbers_p (tree decl, const HARD_REG_SET clobbered_regs)
1405 /* Conflicts between asm-declared register variables and the clobber
1406 list are not allowed. */
1407 if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
1408 && DECL_REGISTER (decl)
1409 && REG_P (DECL_RTL (decl))
1410 && REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
1412 rtx reg = DECL_RTL (decl);
1415 for (regno = REGNO (reg);
1416 regno < (REGNO (reg)
1417 + HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
1419 if (TEST_HARD_REG_BIT (clobbered_regs, regno))
1421 error ("asm-specifier for variable `%s' conflicts with asm clobber list",
1422 IDENTIFIER_POINTER (DECL_NAME (decl)));
1424 /* Reset registerness to stop multiple errors emitted for a
1426 DECL_REGISTER (decl) = 0;
1433 /* Generate RTL for an asm statement with arguments.
1434 STRING is the instruction template.
1435 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1436 Each output or input has an expression in the TREE_VALUE and
1437 and a tree list in TREE_PURPOSE which in turn contains a constraint
1438 name in TREE_VALUE (or NULL_TREE) and a constraint string
1440 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1441 that is clobbered by this insn.
1443 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1444 Some elements of OUTPUTS may be replaced with trees representing temporary
1445 values. The caller should copy those temporary values to the originally
1448 VOL nonzero means the insn is volatile; don't optimize it. */
1451 expand_asm_operands (tree string, tree outputs, tree inputs,
1452 tree clobbers, int vol, location_t locus)
1454 rtvec argvec, constraintvec;
1456 int ninputs = list_length (inputs);
1457 int noutputs = list_length (outputs);
1460 HARD_REG_SET clobbered_regs;
1461 int clobber_conflict_found = 0;
1465 /* Vector of RTX's of evaluated output operands. */
1466 rtx *output_rtx = alloca (noutputs * sizeof (rtx));
1467 int *inout_opnum = alloca (noutputs * sizeof (int));
1468 rtx *real_output_rtx = alloca (noutputs * sizeof (rtx));
1469 enum machine_mode *inout_mode
1470 = alloca (noutputs * sizeof (enum machine_mode));
1471 const char **constraints
1472 = alloca ((noutputs + ninputs) * sizeof (const char *));
1473 int old_generating_concat_p = generating_concat_p;
1475 /* An ASM with no outputs needs to be treated as volatile, for now. */
1479 if (! check_operand_nalternatives (outputs, inputs))
1482 string = resolve_asm_operand_names (string, outputs, inputs);
1484 /* Collect constraints. */
1486 for (t = outputs; t ; t = TREE_CHAIN (t), i++)
1487 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1488 for (t = inputs; t ; t = TREE_CHAIN (t), i++)
1489 constraints[i] = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1491 #ifdef MD_ASM_CLOBBERS
1492 /* Sometimes we wish to automatically clobber registers across an asm.
1493 Case in point is when the i386 backend moved from cc0 to a hard reg --
1494 maintaining source-level compatibility means automatically clobbering
1495 the flags register. */
1496 MD_ASM_CLOBBERS (clobbers);
1499 /* Count the number of meaningful clobbered registers, ignoring what
1500 we would ignore later. */
1502 CLEAR_HARD_REG_SET (clobbered_regs);
1503 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1505 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1507 i = decode_reg_name (regname);
1508 if (i >= 0 || i == -4)
1511 error ("unknown register name `%s' in `asm'", regname);
1513 /* Mark clobbered registers. */
1516 /* Clobbering the PIC register is an error */
1517 if (i == (int) PIC_OFFSET_TABLE_REGNUM)
1519 error ("PIC register `%s' clobbered in `asm'", regname);
1523 SET_HARD_REG_BIT (clobbered_regs, i);
1529 /* First pass over inputs and outputs checks validity and sets
1530 mark_addressable if needed. */
1533 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1535 tree val = TREE_VALUE (tail);
1536 tree type = TREE_TYPE (val);
1537 const char *constraint;
1542 /* If there's an erroneous arg, emit no insn. */
1543 if (type == error_mark_node)
1546 /* Try to parse the output constraint. If that fails, there's
1547 no point in going further. */
1548 constraint = constraints[i];
1549 if (!parse_output_constraint (&constraint, i, ninputs, noutputs,
1550 &allows_mem, &allows_reg, &is_inout))
1557 && GET_CODE (DECL_RTL (val)) == REG
1558 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type))))
1559 (*lang_hooks.mark_addressable) (val);
1566 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1568 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1572 for (i = 0, tail = inputs; tail; i++, tail = TREE_CHAIN (tail))
1574 bool allows_reg, allows_mem;
1575 const char *constraint;
1577 /* If there's an erroneous arg, emit no insn, because the ASM_INPUT
1578 would get VOIDmode and that could cause a crash in reload. */
1579 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1582 constraint = constraints[i + noutputs];
1583 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1584 constraints, &allows_mem, &allows_reg))
1587 if (! allows_reg && allows_mem)
1588 (*lang_hooks.mark_addressable) (TREE_VALUE (tail));
1591 /* Second pass evaluates arguments. */
1594 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1596 tree val = TREE_VALUE (tail);
1597 tree type = TREE_TYPE (val);
1603 if (!parse_output_constraint (&constraints[i], i, ninputs,
1604 noutputs, &allows_mem, &allows_reg,
1608 /* If an output operand is not a decl or indirect ref and our constraint
1609 allows a register, make a temporary to act as an intermediate.
1610 Make the asm insn write into that, then our caller will copy it to
1611 the real output operand. Likewise for promoted variables. */
1613 generating_concat_p = 0;
1615 real_output_rtx[i] = NULL_RTX;
1616 if ((TREE_CODE (val) == INDIRECT_REF
1619 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1620 && ! (GET_CODE (DECL_RTL (val)) == REG
1621 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1625 op = expand_expr (val, NULL_RTX, VOIDmode, EXPAND_WRITE);
1626 if (GET_CODE (op) == MEM)
1627 op = validize_mem (op);
1629 if (! allows_reg && GET_CODE (op) != MEM)
1630 error ("output number %d not directly addressable", i);
1631 if ((! allows_mem && GET_CODE (op) == MEM)
1632 || GET_CODE (op) == CONCAT)
1634 real_output_rtx[i] = protect_from_queue (op, 1);
1635 op = gen_reg_rtx (GET_MODE (op));
1637 emit_move_insn (op, real_output_rtx[i]);
1642 op = assign_temp (type, 0, 0, 1);
1643 op = validize_mem (op);
1644 TREE_VALUE (tail) = make_tree (type, op);
1648 generating_concat_p = old_generating_concat_p;
1652 inout_mode[ninout] = TYPE_MODE (type);
1653 inout_opnum[ninout++] = i;
1656 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1657 clobber_conflict_found = 1;
1660 /* Make vectors for the expression-rtx, constraint strings,
1661 and named operands. */
1663 argvec = rtvec_alloc (ninputs);
1664 constraintvec = rtvec_alloc (ninputs);
1666 body = gen_rtx_ASM_OPERANDS ((noutputs == 0 ? VOIDmode
1667 : GET_MODE (output_rtx[0])),
1668 TREE_STRING_POINTER (string),
1669 empty_string, 0, argvec, constraintvec,
1670 locus.file, locus.line);
1672 MEM_VOLATILE_P (body) = vol;
1674 /* Eval the inputs and put them into ARGVEC.
1675 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1677 for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), ++i)
1679 bool allows_reg, allows_mem;
1680 const char *constraint;
1684 constraint = constraints[i + noutputs];
1685 if (! parse_input_constraint (&constraint, i, ninputs, noutputs, ninout,
1686 constraints, &allows_mem, &allows_reg))
1689 generating_concat_p = 0;
1691 val = TREE_VALUE (tail);
1692 type = TREE_TYPE (val);
1693 op = expand_expr (val, NULL_RTX, VOIDmode,
1694 (allows_mem && !allows_reg
1695 ? EXPAND_MEMORY : EXPAND_NORMAL));
1697 /* Never pass a CONCAT to an ASM. */
1698 if (GET_CODE (op) == CONCAT)
1699 op = force_reg (GET_MODE (op), op);
1700 else if (GET_CODE (op) == MEM)
1701 op = validize_mem (op);
1703 if (asm_operand_ok (op, constraint) <= 0)
1706 op = force_reg (TYPE_MODE (type), op);
1707 else if (!allows_mem)
1708 warning ("asm operand %d probably doesn't match constraints",
1710 else if (GET_CODE (op) == MEM)
1712 /* We won't recognize either volatile memory or memory
1713 with a queued address as available a memory_operand
1714 at this point. Ignore it: clearly this *is* a memory. */
1718 warning ("use of memory input without lvalue in "
1719 "asm operand %d is deprecated", i + noutputs);
1721 if (CONSTANT_P (op))
1723 rtx mem = force_const_mem (TYPE_MODE (type), op);
1725 op = validize_mem (mem);
1727 op = force_reg (TYPE_MODE (type), op);
1729 if (GET_CODE (op) == REG
1730 || GET_CODE (op) == SUBREG
1731 || GET_CODE (op) == ADDRESSOF
1732 || GET_CODE (op) == CONCAT)
1734 tree qual_type = build_qualified_type (type,
1736 | TYPE_QUAL_CONST));
1737 rtx memloc = assign_temp (qual_type, 1, 1, 1);
1738 memloc = validize_mem (memloc);
1739 emit_move_insn (memloc, op);
1745 generating_concat_p = old_generating_concat_p;
1746 ASM_OPERANDS_INPUT (body, i) = op;
1748 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
1749 = gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
1751 if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
1752 clobber_conflict_found = 1;
1755 /* Protect all the operands from the queue now that they have all been
1758 generating_concat_p = 0;
1760 for (i = 0; i < ninputs - ninout; i++)
1761 ASM_OPERANDS_INPUT (body, i)
1762 = protect_from_queue (ASM_OPERANDS_INPUT (body, i), 0);
1764 for (i = 0; i < noutputs; i++)
1765 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1767 /* For in-out operands, copy output rtx to input rtx. */
1768 for (i = 0; i < ninout; i++)
1770 int j = inout_opnum[i];
1773 ASM_OPERANDS_INPUT (body, ninputs - ninout + i)
1776 sprintf (buffer, "%d", j);
1777 ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, ninputs - ninout + i)
1778 = gen_rtx_ASM_INPUT (inout_mode[i], ggc_strdup (buffer));
1781 generating_concat_p = old_generating_concat_p;
1783 /* Now, for each output, construct an rtx
1784 (set OUTPUT (asm_operands INSN OUTPUTCONSTRAINT OUTPUTNUMBER
1785 ARGVEC CONSTRAINTS OPNAMES))
1786 If there is more than one, put them inside a PARALLEL. */
1788 if (noutputs == 1 && nclobbers == 0)
1790 ASM_OPERANDS_OUTPUT_CONSTRAINT (body) = constraints[0];
1791 emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1794 else if (noutputs == 0 && nclobbers == 0)
1796 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1808 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1810 /* For each output operand, store a SET. */
1811 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1813 XVECEXP (body, 0, i)
1814 = gen_rtx_SET (VOIDmode,
1816 gen_rtx_ASM_OPERANDS
1817 (GET_MODE (output_rtx[i]),
1818 TREE_STRING_POINTER (string),
1819 constraints[i], i, argvec, constraintvec,
1820 locus.file, locus.line));
1822 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1825 /* If there are no outputs (but there are some clobbers)
1826 store the bare ASM_OPERANDS into the PARALLEL. */
1829 XVECEXP (body, 0, i++) = obody;
1831 /* Store (clobber REG) for each clobbered register specified. */
1833 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1835 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1836 int j = decode_reg_name (regname);
1841 if (j == -3) /* `cc', which is not a register */
1844 if (j == -4) /* `memory', don't cache memory across asm */
1846 XVECEXP (body, 0, i++)
1847 = gen_rtx_CLOBBER (VOIDmode,
1850 gen_rtx_SCRATCH (VOIDmode)));
1854 /* Ignore unknown register, error already signaled. */
1858 /* Use QImode since that's guaranteed to clobber just one reg. */
1859 clobbered_reg = gen_rtx_REG (QImode, j);
1861 /* Do sanity check for overlap between clobbers and respectively
1862 input and outputs that hasn't been handled. Such overlap
1863 should have been detected and reported above. */
1864 if (!clobber_conflict_found)
1868 /* We test the old body (obody) contents to avoid tripping
1869 over the under-construction body. */
1870 for (opno = 0; opno < noutputs; opno++)
1871 if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
1872 internal_error ("asm clobber conflict with output operand");
1874 for (opno = 0; opno < ninputs - ninout; opno++)
1875 if (reg_overlap_mentioned_p (clobbered_reg,
1876 ASM_OPERANDS_INPUT (obody, opno)))
1877 internal_error ("asm clobber conflict with input operand");
1880 XVECEXP (body, 0, i++)
1881 = gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
1887 /* For any outputs that needed reloading into registers, spill them
1888 back to where they belong. */
1889 for (i = 0; i < noutputs; ++i)
1890 if (real_output_rtx[i])
1891 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1896 /* A subroutine of expand_asm_operands. Check that all operands have
1897 the same number of alternatives. Return true if so. */
1900 check_operand_nalternatives (tree outputs, tree inputs)
1902 if (outputs || inputs)
1904 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1906 = n_occurrences (',', TREE_STRING_POINTER (TREE_VALUE (tmp)));
1909 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1911 error ("too many alternatives in `asm'");
1918 const char *constraint
1919 = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (tmp)));
1921 if (n_occurrences (',', constraint) != nalternatives)
1923 error ("operand constraints for `asm' differ in number of alternatives");
1927 if (TREE_CHAIN (tmp))
1928 tmp = TREE_CHAIN (tmp);
1930 tmp = next, next = 0;
1937 /* A subroutine of expand_asm_operands. Check that all operand names
1938 are unique. Return true if so. We rely on the fact that these names
1939 are identifiers, and so have been canonicalized by get_identifier,
1940 so all we need are pointer comparisons. */
1943 check_unique_operand_names (tree outputs, tree inputs)
1947 for (i = outputs; i ; i = TREE_CHAIN (i))
1949 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1953 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1954 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1958 for (i = inputs; i ; i = TREE_CHAIN (i))
1960 tree i_name = TREE_PURPOSE (TREE_PURPOSE (i));
1964 for (j = TREE_CHAIN (i); j ; j = TREE_CHAIN (j))
1965 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1967 for (j = outputs; j ; j = TREE_CHAIN (j))
1968 if (simple_cst_equal (i_name, TREE_PURPOSE (TREE_PURPOSE (j))))
1975 error ("duplicate asm operand name '%s'",
1976 TREE_STRING_POINTER (TREE_PURPOSE (TREE_PURPOSE (i))));
1980 /* A subroutine of expand_asm_operands. Resolve the names of the operands
1981 in *POUTPUTS and *PINPUTS to numbers, and replace the name expansions in
1982 STRING and in the constraints to those numbers. */
1985 resolve_asm_operand_names (tree string, tree outputs, tree inputs)
1992 check_unique_operand_names (outputs, inputs);
1994 /* Substitute [<name>] in input constraint strings. There should be no
1995 named operands in output constraints. */
1996 for (t = inputs; t ; t = TREE_CHAIN (t))
1998 c = TREE_STRING_POINTER (TREE_VALUE (TREE_PURPOSE (t)));
1999 if (strchr (c, '[') != NULL)
2001 p = buffer = xstrdup (c);
2002 while ((p = strchr (p, '[')) != NULL)
2003 p = resolve_operand_name_1 (p, outputs, inputs);
2004 TREE_VALUE (TREE_PURPOSE (t))
2005 = build_string (strlen (buffer), buffer);
2010 /* Now check for any needed substitutions in the template. */
2011 c = TREE_STRING_POINTER (string);
2012 while ((c = strchr (c, '%')) != NULL)
2016 else if (ISALPHA (c[1]) && c[2] == '[')
2027 /* OK, we need to make a copy so we can perform the substitutions.
2028 Assume that we will not need extra space--we get to remove '['
2029 and ']', which means we cannot have a problem until we have more
2030 than 999 operands. */
2031 buffer = xstrdup (TREE_STRING_POINTER (string));
2032 p = buffer + (c - TREE_STRING_POINTER (string));
2034 while ((p = strchr (p, '%')) != NULL)
2038 else if (ISALPHA (p[1]) && p[2] == '[')
2046 p = resolve_operand_name_1 (p, outputs, inputs);
2049 string = build_string (strlen (buffer), buffer);
2056 /* A subroutine of resolve_operand_names. P points to the '[' for a
2057 potential named operand of the form [<name>]. In place, replace
2058 the name and brackets with a number. Return a pointer to the
2059 balance of the string after substitution. */
2062 resolve_operand_name_1 (char *p, tree outputs, tree inputs)
2069 /* Collect the operand name. */
2070 q = strchr (p, ']');
2073 error ("missing close brace for named operand");
2074 return strchr (p, '\0');
2078 /* Resolve the name to a number. */
2079 for (op = 0, t = outputs; t ; t = TREE_CHAIN (t), op++)
2081 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2084 const char *c = TREE_STRING_POINTER (name);
2085 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2089 for (t = inputs; t ; t = TREE_CHAIN (t), op++)
2091 tree name = TREE_PURPOSE (TREE_PURPOSE (t));
2094 const char *c = TREE_STRING_POINTER (name);
2095 if (strncmp (c, p + 1, len) == 0 && c[len] == '\0')
2101 error ("undefined named operand '%s'", p + 1);
2105 /* Replace the name with the number. Unfortunately, not all libraries
2106 get the return value of sprintf correct, so search for the end of the
2107 generated string by hand. */
2108 sprintf (p, "%d", op);
2109 p = strchr (p, '\0');
2111 /* Verify the no extra buffer space assumption. */
2115 /* Shift the rest of the buffer down to fill the gap. */
2116 memmove (p, q + 1, strlen (q + 1) + 1);
2121 /* Generate RTL to evaluate the expression EXP
2122 and remember it in case this is the VALUE in a ({... VALUE; }) constr.
2123 Provided just for backward-compatibility. expand_expr_stmt_value()
2124 should be used for new code. */
2127 expand_expr_stmt (tree exp)
2129 expand_expr_stmt_value (exp, -1, 1);
2132 /* Generate RTL to evaluate the expression EXP. WANT_VALUE tells
2133 whether to (1) save the value of the expression, (0) discard it or
2134 (-1) use expr_stmts_for_value to tell. The use of -1 is
2135 deprecated, and retained only for backward compatibility. */
2138 expand_expr_stmt_value (tree exp, int want_value, int maybe_last)
2144 if (want_value == -1)
2145 want_value = expr_stmts_for_value != 0;
2147 /* If -Wextra, warn about statements with no side effects,
2148 except for an explicit cast to void (e.g. for assert()), and
2149 except for last statement in ({...}) where they may be useful. */
2151 && (expr_stmts_for_value == 0 || ! maybe_last)
2152 && exp != error_mark_node
2153 && warn_unused_value)
2155 if (TREE_SIDE_EFFECTS (exp))
2156 warn_if_unused_value (exp);
2157 else if (!VOID_TYPE_P (TREE_TYPE (exp)))
2158 warning ("%Hstatement with no effect", &emit_locus);
2161 /* If EXP is of function type and we are expanding statements for
2162 value, convert it to pointer-to-function. */
2163 if (want_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
2164 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
2166 /* The call to `expand_expr' could cause last_expr_type and
2167 last_expr_value to get reset. Therefore, we set last_expr_value
2168 and last_expr_type *after* calling expand_expr. */
2169 value = expand_expr_real (exp, want_value ? NULL_RTX : const0_rtx,
2170 VOIDmode, 0, &alt_rtl);
2171 type = TREE_TYPE (exp);
2173 /* If all we do is reference a volatile value in memory,
2174 copy it to a register to be sure it is actually touched. */
2175 if (value && GET_CODE (value) == MEM && TREE_THIS_VOLATILE (exp))
2177 if (TYPE_MODE (type) == VOIDmode)
2179 else if (TYPE_MODE (type) != BLKmode)
2180 value = copy_to_reg (value);
2183 rtx lab = gen_label_rtx ();
2185 /* Compare the value with itself to reference it. */
2186 emit_cmp_and_jump_insns (value, value, EQ,
2187 expand_expr (TYPE_SIZE (type),
2188 NULL_RTX, VOIDmode, 0),
2194 /* If this expression is part of a ({...}) and is in memory, we may have
2195 to preserve temporaries. */
2196 preserve_temp_slots (value);
2198 /* Free any temporaries used to evaluate this expression. Any temporary
2199 used as a result of this expression will already have been preserved
2205 last_expr_value = value;
2206 last_expr_alt_rtl = alt_rtl;
2207 last_expr_type = type;
2213 /* Warn if EXP contains any computations whose results are not used.
2214 Return 1 if a warning is printed; 0 otherwise. */
2217 warn_if_unused_value (tree exp)
2219 if (TREE_USED (exp))
2222 /* Don't warn about void constructs. This includes casting to void,
2223 void function calls, and statement expressions with a final cast
2225 if (VOID_TYPE_P (TREE_TYPE (exp)))
2228 switch (TREE_CODE (exp))
2230 case PREINCREMENT_EXPR:
2231 case POSTINCREMENT_EXPR:
2232 case PREDECREMENT_EXPR:
2233 case POSTDECREMENT_EXPR:
2239 case TRY_CATCH_EXPR:
2240 case WITH_CLEANUP_EXPR:
2245 /* For a binding, warn if no side effect within it. */
2246 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2249 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2251 case TRUTH_ORIF_EXPR:
2252 case TRUTH_ANDIF_EXPR:
2253 /* In && or ||, warn if 2nd operand has no side effect. */
2254 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2257 if (TREE_NO_UNUSED_WARNING (exp))
2259 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
2261 /* Let people do `(foo (), 0)' without a warning. */
2262 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
2264 return warn_if_unused_value (TREE_OPERAND (exp, 1));
2268 case NON_LVALUE_EXPR:
2269 /* Don't warn about conversions not explicit in the user's program. */
2270 if (TREE_NO_UNUSED_WARNING (exp))
2272 /* Assignment to a cast usually results in a cast of a modify.
2273 Don't complain about that. There can be an arbitrary number of
2274 casts before the modify, so we must loop until we find the first
2275 non-cast expression and then test to see if that is a modify. */
2277 tree tem = TREE_OPERAND (exp, 0);
2279 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
2280 tem = TREE_OPERAND (tem, 0);
2282 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
2283 || TREE_CODE (tem) == CALL_EXPR)
2289 /* Don't warn about automatic dereferencing of references, since
2290 the user cannot control it. */
2291 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
2292 return warn_if_unused_value (TREE_OPERAND (exp, 0));
2296 /* Referencing a volatile value is a side effect, so don't warn. */
2298 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
2299 && TREE_THIS_VOLATILE (exp))
2302 /* If this is an expression which has no operands, there is no value
2303 to be unused. There are no such language-independent codes,
2304 but front ends may define such. */
2305 if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'e'
2306 && TREE_CODE_LENGTH (TREE_CODE (exp)) == 0)
2310 /* If this is an expression with side effects, don't warn. */
2311 if (TREE_SIDE_EFFECTS (exp))
2314 warning ("%Hvalue computed is not used", &emit_locus);
2319 /* Clear out the memory of the last expression evaluated. */
2322 clear_last_expr (void)
2324 last_expr_type = NULL_TREE;
2325 last_expr_value = NULL_RTX;
2326 last_expr_alt_rtl = NULL_RTX;
2329 /* Begin a statement-expression, i.e., a series of statements which
2330 may return a value. Return the RTL_EXPR for this statement expr.
2331 The caller must save that value and pass it to
2332 expand_end_stmt_expr. If HAS_SCOPE is nonzero, temporaries created
2333 in the statement-expression are deallocated at the end of the
2337 expand_start_stmt_expr (int has_scope)
2341 /* Make the RTL_EXPR node temporary, not momentary,
2342 so that rtl_expr_chain doesn't become garbage. */
2343 t = make_node (RTL_EXPR);
2344 do_pending_stack_adjust ();
2346 start_sequence_for_rtl_expr (t);
2350 expr_stmts_for_value++;
2354 /* Restore the previous state at the end of a statement that returns a value.
2355 Returns a tree node representing the statement's value and the
2356 insns to compute the value.
2358 The nodes of that expression have been freed by now, so we cannot use them.
2359 But we don't want to do that anyway; the expression has already been
2360 evaluated and now we just want to use the value. So generate a RTL_EXPR
2361 with the proper type and RTL value.
2363 If the last substatement was not an expression,
2364 return something with type `void'. */
2367 expand_end_stmt_expr (tree t)
2371 if (! last_expr_value || ! last_expr_type)
2373 last_expr_value = const0_rtx;
2374 last_expr_alt_rtl = NULL_RTX;
2375 last_expr_type = void_type_node;
2377 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2378 /* Remove any possible QUEUED. */
2379 last_expr_value = protect_from_queue (last_expr_value, 0);
2383 TREE_TYPE (t) = last_expr_type;
2384 RTL_EXPR_RTL (t) = last_expr_value;
2385 RTL_EXPR_ALT_RTL (t) = last_expr_alt_rtl;
2386 RTL_EXPR_SEQUENCE (t) = get_insns ();
2388 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2392 /* Don't consider deleting this expr or containing exprs at tree level. */
2393 TREE_SIDE_EFFECTS (t) = 1;
2394 /* Propagate volatility of the actual RTL expr. */
2395 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2398 expr_stmts_for_value--;
2403 /* Generate RTL for the start of an if-then. COND is the expression
2404 whose truth should be tested.
2406 If EXITFLAG is nonzero, this conditional is visible to
2407 `exit_something'. */
2410 expand_start_cond (tree cond, int exitflag)
2412 struct nesting *thiscond = ALLOC_NESTING ();
2414 /* Make an entry on cond_stack for the cond we are entering. */
2416 thiscond->desc = COND_NESTING;
2417 thiscond->next = cond_stack;
2418 thiscond->all = nesting_stack;
2419 thiscond->depth = ++nesting_depth;
2420 thiscond->data.cond.next_label = gen_label_rtx ();
2421 /* Before we encounter an `else', we don't need a separate exit label
2422 unless there are supposed to be exit statements
2423 to exit this conditional. */
2424 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2425 thiscond->data.cond.endif_label = thiscond->exit_label;
2426 cond_stack = thiscond;
2427 nesting_stack = thiscond;
2429 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2432 /* Generate RTL between then-clause and the elseif-clause
2433 of an if-then-elseif-.... */
2436 expand_start_elseif (tree cond)
2438 if (cond_stack->data.cond.endif_label == 0)
2439 cond_stack->data.cond.endif_label = gen_label_rtx ();
2440 emit_jump (cond_stack->data.cond.endif_label);
2441 emit_label (cond_stack->data.cond.next_label);
2442 cond_stack->data.cond.next_label = gen_label_rtx ();
2443 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2446 /* Generate RTL between the then-clause and the else-clause
2447 of an if-then-else. */
2450 expand_start_else (void)
2452 if (cond_stack->data.cond.endif_label == 0)
2453 cond_stack->data.cond.endif_label = gen_label_rtx ();
2455 emit_jump (cond_stack->data.cond.endif_label);
2456 emit_label (cond_stack->data.cond.next_label);
2457 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2460 /* After calling expand_start_else, turn this "else" into an "else if"
2461 by providing another condition. */
2464 expand_elseif (tree cond)
2466 cond_stack->data.cond.next_label = gen_label_rtx ();
2467 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2470 /* Generate RTL for the end of an if-then.
2471 Pop the record for it off of cond_stack. */
2474 expand_end_cond (void)
2476 struct nesting *thiscond = cond_stack;
2478 do_pending_stack_adjust ();
2479 if (thiscond->data.cond.next_label)
2480 emit_label (thiscond->data.cond.next_label);
2481 if (thiscond->data.cond.endif_label)
2482 emit_label (thiscond->data.cond.endif_label);
2484 POPSTACK (cond_stack);
2488 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2489 loop should be exited by `exit_something'. This is a loop for which
2490 `expand_continue' will jump to the top of the loop.
2492 Make an entry on loop_stack to record the labels associated with
2496 expand_start_loop (int exit_flag)
2498 struct nesting *thisloop = ALLOC_NESTING ();
2500 /* Make an entry on loop_stack for the loop we are entering. */
2502 thisloop->desc = LOOP_NESTING;
2503 thisloop->next = loop_stack;
2504 thisloop->all = nesting_stack;
2505 thisloop->depth = ++nesting_depth;
2506 thisloop->data.loop.start_label = gen_label_rtx ();
2507 thisloop->data.loop.end_label = gen_label_rtx ();
2508 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2509 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2510 loop_stack = thisloop;
2511 nesting_stack = thisloop;
2513 do_pending_stack_adjust ();
2515 emit_note (NOTE_INSN_LOOP_BEG);
2516 emit_label (thisloop->data.loop.start_label);
2521 /* Like expand_start_loop but for a loop where the continuation point
2522 (for expand_continue_loop) will be specified explicitly. */
2525 expand_start_loop_continue_elsewhere (int exit_flag)
2527 struct nesting *thisloop = expand_start_loop (exit_flag);
2528 loop_stack->data.loop.continue_label = gen_label_rtx ();
2532 /* Begin a null, aka do { } while (0) "loop". But since the contents
2533 of said loop can still contain a break, we must frob the loop nest. */
2536 expand_start_null_loop (void)
2538 struct nesting *thisloop = ALLOC_NESTING ();
2540 /* Make an entry on loop_stack for the loop we are entering. */
2542 thisloop->desc = LOOP_NESTING;
2543 thisloop->next = loop_stack;
2544 thisloop->all = nesting_stack;
2545 thisloop->depth = ++nesting_depth;
2546 thisloop->data.loop.start_label = emit_note (NOTE_INSN_DELETED);
2547 thisloop->data.loop.end_label = gen_label_rtx ();
2548 thisloop->data.loop.continue_label = thisloop->data.loop.end_label;
2549 thisloop->exit_label = thisloop->data.loop.end_label;
2550 loop_stack = thisloop;
2551 nesting_stack = thisloop;
2556 /* Specify the continuation point for a loop started with
2557 expand_start_loop_continue_elsewhere.
2558 Use this at the point in the code to which a continue statement
2562 expand_loop_continue_here (void)
2564 do_pending_stack_adjust ();
2565 emit_note (NOTE_INSN_LOOP_CONT);
2566 emit_label (loop_stack->data.loop.continue_label);
2569 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2570 Pop the block off of loop_stack. */
2573 expand_end_loop (void)
2575 rtx start_label = loop_stack->data.loop.start_label;
2577 int eh_regions, debug_blocks;
2580 /* Mark the continue-point at the top of the loop if none elsewhere. */
2581 if (start_label == loop_stack->data.loop.continue_label)
2582 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2584 do_pending_stack_adjust ();
2586 /* If the loop starts with a loop exit, roll that to the end where
2587 it will optimize together with the jump back.
2589 If the loop presently looks like this (in pseudo-C):
2593 if (test) goto end_label;
2599 transform it to look like:
2606 if (test) goto end_label;
2610 We rely on the presence of NOTE_INSN_LOOP_END_TOP_COND to mark
2611 the end of the entry conditional. Without this, our lexical scan
2612 can't tell the difference between an entry conditional and a
2613 body conditional that exits the loop. Mistaking the two means
2614 that we can misplace the NOTE_INSN_LOOP_CONT note, which can
2615 screw up loop unrolling.
2617 Things will be oh so much better when loop optimization is done
2618 off of a proper control flow graph... */
2620 /* Scan insns from the top of the loop looking for the END_TOP_COND note. */
2623 eh_regions = debug_blocks = 0;
2624 for (etc_note = start_label; etc_note ; etc_note = NEXT_INSN (etc_note))
2625 if (GET_CODE (etc_note) == NOTE)
2627 if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_END_TOP_COND)
2630 /* We must not walk into a nested loop. */
2631 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_LOOP_BEG)
2633 etc_note = NULL_RTX;
2637 /* At the same time, scan for EH region notes, as we don't want
2638 to scrog region nesting. This shouldn't happen, but... */
2639 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_BEG)
2641 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_EH_REGION_END)
2643 if (--eh_regions < 0)
2644 /* We've come to the end of an EH region, but never saw the
2645 beginning of that region. That means that an EH region
2646 begins before the top of the loop, and ends in the middle
2647 of it. The existence of such a situation violates a basic
2648 assumption in this code, since that would imply that even
2649 when EH_REGIONS is zero, we might move code out of an
2650 exception region. */
2654 /* Likewise for debug scopes. In this case we'll either (1) move
2655 all of the notes if they are properly nested or (2) leave the
2656 notes alone and only rotate the loop at high optimization
2657 levels when we expect to scrog debug info. */
2658 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_BEG)
2660 else if (NOTE_LINE_NUMBER (etc_note) == NOTE_INSN_BLOCK_END)
2663 else if (INSN_P (etc_note))
2670 && (debug_blocks == 0 || optimize >= 2)
2671 && NEXT_INSN (etc_note) != NULL_RTX
2672 && ! any_condjump_p (get_last_insn ()))
2674 /* We found one. Move everything from START to ETC to the end
2675 of the loop, and add a jump from the top of the loop. */
2676 rtx top_label = gen_label_rtx ();
2677 rtx start_move = start_label;
2679 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2680 then we want to move this note also. */
2681 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2682 && NOTE_LINE_NUMBER (PREV_INSN (start_move)) == NOTE_INSN_LOOP_CONT)
2683 start_move = PREV_INSN (start_move);
2685 emit_label_before (top_label, start_move);
2687 /* Actually move the insns. If the debug scopes are nested, we
2688 can move everything at once. Otherwise we have to move them
2689 one by one and squeeze out the block notes. */
2690 if (debug_blocks == 0)
2691 reorder_insns (start_move, etc_note, get_last_insn ());
2694 rtx insn, next_insn;
2695 for (insn = start_move; insn; insn = next_insn)
2697 /* Figure out which insn comes after this one. We have
2698 to do this before we move INSN. */
2699 next_insn = (insn == etc_note ? NULL : NEXT_INSN (insn));
2701 if (GET_CODE (insn) == NOTE
2702 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2703 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2706 reorder_insns (insn, insn, get_last_insn ());
2710 /* Add the jump from the top of the loop. */
2711 emit_jump_insn_before (gen_jump (start_label), top_label);
2712 emit_barrier_before (top_label);
2713 start_label = top_label;
2716 emit_jump (start_label);
2717 emit_note (NOTE_INSN_LOOP_END);
2718 emit_label (loop_stack->data.loop.end_label);
2720 POPSTACK (loop_stack);
2725 /* Finish a null loop, aka do { } while (0). */
2728 expand_end_null_loop (void)
2730 do_pending_stack_adjust ();
2731 emit_label (loop_stack->data.loop.end_label);
2733 POPSTACK (loop_stack);
2738 /* Generate a jump to the current loop's continue-point.
2739 This is usually the top of the loop, but may be specified
2740 explicitly elsewhere. If not currently inside a loop,
2741 return 0 and do nothing; caller will print an error message. */
2744 expand_continue_loop (struct nesting *whichloop)
2746 /* Emit information for branch prediction. */
2749 if (flag_guess_branch_prob)
2751 note = emit_note (NOTE_INSN_PREDICTION);
2752 NOTE_PREDICTION (note) = NOTE_PREDICT (PRED_CONTINUE, IS_TAKEN);
2756 whichloop = loop_stack;
2759 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2764 /* Generate a jump to exit the current loop. If not currently inside a loop,
2765 return 0 and do nothing; caller will print an error message. */
2768 expand_exit_loop (struct nesting *whichloop)
2772 whichloop = loop_stack;
2775 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2779 /* Generate a conditional jump to exit the current loop if COND
2780 evaluates to zero. If not currently inside a loop,
2781 return 0 and do nothing; caller will print an error message. */
2784 expand_exit_loop_if_false (struct nesting *whichloop, tree cond)
2790 whichloop = loop_stack;
2794 if (integer_nonzerop (cond))
2796 if (integer_zerop (cond))
2797 return expand_exit_loop (whichloop);
2799 /* Check if we definitely won't need a fixup. */
2800 if (whichloop == nesting_stack)
2802 jumpifnot (cond, whichloop->data.loop.end_label);
2806 /* In order to handle fixups, we actually create a conditional jump
2807 around an unconditional branch to exit the loop. If fixups are
2808 necessary, they go before the unconditional branch. */
2810 label = gen_label_rtx ();
2811 jumpif (cond, label);
2812 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2819 /* Like expand_exit_loop_if_false except also emit a note marking
2820 the end of the conditional. Should only be used immediately
2821 after expand_loop_start. */
2824 expand_exit_loop_top_cond (struct nesting *whichloop, tree cond)
2826 if (! expand_exit_loop_if_false (whichloop, cond))
2829 emit_note (NOTE_INSN_LOOP_END_TOP_COND);
2833 /* Return nonzero if we should preserve sub-expressions as separate
2834 pseudos. We never do so if we aren't optimizing. We always do so
2835 if -fexpensive-optimizations.
2837 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2838 the loop may still be a small one. */
2841 preserve_subexpressions_p (void)
2845 if (flag_expensive_optimizations)
2848 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2851 insn = get_last_insn_anywhere ();
2854 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2855 < n_non_fixed_regs * 3));
2859 /* Generate a jump to exit the current loop, conditional, binding contour
2860 or case statement. Not all such constructs are visible to this function,
2861 only those started with EXIT_FLAG nonzero. Individual languages use
2862 the EXIT_FLAG parameter to control which kinds of constructs you can
2865 If not currently inside anything that can be exited,
2866 return 0 and do nothing; caller will print an error message. */
2869 expand_exit_something (void)
2873 for (n = nesting_stack; n; n = n->all)
2874 if (n->exit_label != 0)
2876 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2883 /* Generate RTL to return from the current function, with no value.
2884 (That is, we do not do anything about returning any value.) */
2887 expand_null_return (void)
2891 last_insn = get_last_insn ();
2893 /* If this function was declared to return a value, but we
2894 didn't, clobber the return registers so that they are not
2895 propagated live to the rest of the function. */
2896 clobber_return_register ();
2898 expand_null_return_1 (last_insn);
2901 /* Generate RTL to return directly from the current function.
2902 (That is, we bypass any return value.) */
2905 expand_naked_return (void)
2907 rtx last_insn, end_label;
2909 last_insn = get_last_insn ();
2910 end_label = naked_return_label;
2912 clear_pending_stack_adjust ();
2913 do_pending_stack_adjust ();
2917 end_label = naked_return_label = gen_label_rtx ();
2918 expand_goto_internal (NULL_TREE, end_label, last_insn);
2921 /* Try to guess whether the value of return means error code. */
2922 static enum br_predictor
2923 return_prediction (rtx val)
2925 /* Different heuristics for pointers and scalars. */
2926 if (POINTER_TYPE_P (TREE_TYPE (DECL_RESULT (current_function_decl))))
2928 /* NULL is usually not returned. */
2929 if (val == const0_rtx)
2930 return PRED_NULL_RETURN;
2934 /* Negative return values are often used to indicate
2936 if (GET_CODE (val) == CONST_INT
2937 && INTVAL (val) < 0)
2938 return PRED_NEGATIVE_RETURN;
2939 /* Constant return values are also usually erors,
2940 zero/one often mean booleans so exclude them from the
2942 if (CONSTANT_P (val)
2943 && (val != const0_rtx && val != const1_rtx))
2944 return PRED_CONST_RETURN;
2946 return PRED_NO_PREDICTION;
2950 /* If the current function returns values in the most significant part
2951 of a register, shift return value VAL appropriately. The mode of
2952 the function's return type is known not to be BLKmode. */
2955 shift_return_value (rtx val)
2959 type = TREE_TYPE (DECL_RESULT (current_function_decl));
2960 if (targetm.calls.return_in_msb (type))
2963 HOST_WIDE_INT shift;
2965 target = DECL_RTL (DECL_RESULT (current_function_decl));
2966 shift = (GET_MODE_BITSIZE (GET_MODE (target))
2967 - BITS_PER_UNIT * int_size_in_bytes (type));
2969 val = expand_binop (GET_MODE (target), ashl_optab,
2970 gen_lowpart (GET_MODE (target), val),
2971 GEN_INT (shift), target, 1, OPTAB_WIDEN);
2977 /* Generate RTL to return from the current function, with value VAL. */
2980 expand_value_return (rtx val)
2984 enum br_predictor pred;
2986 if (flag_guess_branch_prob
2987 && (pred = return_prediction (val)) != PRED_NO_PREDICTION)
2989 /* Emit information for branch prediction. */
2992 note = emit_note (NOTE_INSN_PREDICTION);
2994 NOTE_PREDICTION (note) = NOTE_PREDICT (pred, NOT_TAKEN);
2998 last_insn = get_last_insn ();
2999 return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
3001 /* Copy the value to the return location
3002 unless it's already there. */
3004 if (return_reg != val)
3006 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
3007 if (targetm.calls.promote_function_return (TREE_TYPE (current_function_decl)))
3009 int unsignedp = TREE_UNSIGNED (type);
3010 enum machine_mode old_mode
3011 = DECL_MODE (DECL_RESULT (current_function_decl));
3012 enum machine_mode mode
3013 = promote_mode (type, old_mode, &unsignedp, 1);
3015 if (mode != old_mode)
3016 val = convert_modes (mode, old_mode, val, unsignedp);
3018 if (GET_CODE (return_reg) == PARALLEL)
3019 emit_group_load (return_reg, val, type, int_size_in_bytes (type));
3021 emit_move_insn (return_reg, val);
3024 expand_null_return_1 (last_insn);
3027 /* Output a return with no value. If LAST_INSN is nonzero,
3028 pretend that the return takes place after LAST_INSN. */
3031 expand_null_return_1 (rtx last_insn)
3033 rtx end_label = cleanup_label ? cleanup_label : return_label;
3035 clear_pending_stack_adjust ();
3036 do_pending_stack_adjust ();
3040 end_label = return_label = gen_label_rtx ();
3041 expand_goto_internal (NULL_TREE, end_label, last_insn);
3044 /* Generate RTL to evaluate the expression RETVAL and return it
3045 from the current function. */
3048 expand_return (tree retval)
3050 /* If there are any cleanups to be performed, then they will
3051 be inserted following LAST_INSN. It is desirable
3052 that the last_insn, for such purposes, should be the
3053 last insn before computing the return value. Otherwise, cleanups
3054 which call functions can clobber the return value. */
3055 /* ??? rms: I think that is erroneous, because in C++ it would
3056 run destructors on variables that might be used in the subsequent
3057 computation of the return value. */
3063 /* If function wants no value, give it none. */
3064 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
3066 expand_expr (retval, NULL_RTX, VOIDmode, 0);
3068 expand_null_return ();
3072 if (retval == error_mark_node)
3074 /* Treat this like a return of no value from a function that
3076 expand_null_return ();
3079 else if (TREE_CODE (retval) == RESULT_DECL)
3080 retval_rhs = retval;
3081 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
3082 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
3083 retval_rhs = TREE_OPERAND (retval, 1);
3084 else if (VOID_TYPE_P (TREE_TYPE (retval)))
3085 /* Recognize tail-recursive call to void function. */
3086 retval_rhs = retval;
3088 retval_rhs = NULL_TREE;
3090 last_insn = get_last_insn ();
3092 /* Distribute return down conditional expr if either of the sides
3093 may involve tail recursion (see test below). This enhances the number
3094 of tail recursions we see. Don't do this always since it can produce
3095 sub-optimal code in some cases and we distribute assignments into
3096 conditional expressions when it would help. */
3098 if (optimize && retval_rhs != 0
3099 && frame_offset == 0
3100 && TREE_CODE (retval_rhs) == COND_EXPR
3101 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
3102 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
3104 rtx label = gen_label_rtx ();
3107 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
3108 start_cleanup_deferral ();
3109 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3110 DECL_RESULT (current_function_decl),
3111 TREE_OPERAND (retval_rhs, 1));
3112 TREE_SIDE_EFFECTS (expr) = 1;
3113 expand_return (expr);
3116 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
3117 DECL_RESULT (current_function_decl),
3118 TREE_OPERAND (retval_rhs, 2));
3119 TREE_SIDE_EFFECTS (expr) = 1;
3120 expand_return (expr);
3121 end_cleanup_deferral ();
3125 result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
3127 /* If the result is an aggregate that is being returned in one (or more)
3128 registers, load the registers here. The compiler currently can't handle
3129 copying a BLKmode value into registers. We could put this code in a
3130 more general area (for use by everyone instead of just function
3131 call/return), but until this feature is generally usable it is kept here
3132 (and in expand_call). The value must go into a pseudo in case there
3133 are cleanups that will clobber the real return register. */
3136 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
3137 && GET_CODE (result_rtl) == REG)
3140 unsigned HOST_WIDE_INT bitpos, xbitpos;
3141 unsigned HOST_WIDE_INT padding_correction = 0;
3142 unsigned HOST_WIDE_INT bytes
3143 = int_size_in_bytes (TREE_TYPE (retval_rhs));
3144 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
3145 unsigned int bitsize
3146 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
3147 rtx *result_pseudos = alloca (sizeof (rtx) * n_regs);
3148 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
3149 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
3150 enum machine_mode tmpmode, result_reg_mode;
3154 expand_null_return ();
3158 /* If the structure doesn't take up a whole number of words, see
3159 whether the register value should be padded on the left or on
3160 the right. Set PADDING_CORRECTION to the number of padding
3161 bits needed on the left side.
3163 In most ABIs, the structure will be returned at the least end of
3164 the register, which translates to right padding on little-endian
3165 targets and left padding on big-endian targets. The opposite
3166 holds if the structure is returned at the most significant
3167 end of the register. */
3168 if (bytes % UNITS_PER_WORD != 0
3169 && (targetm.calls.return_in_msb (TREE_TYPE (retval_rhs))
3171 : BYTES_BIG_ENDIAN))
3172 padding_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
3175 /* Copy the structure BITSIZE bits at a time. */
3176 for (bitpos = 0, xbitpos = padding_correction;
3177 bitpos < bytes * BITS_PER_UNIT;
3178 bitpos += bitsize, xbitpos += bitsize)
3180 /* We need a new destination pseudo each time xbitpos is
3181 on a word boundary and when xbitpos == padding_correction
3182 (the first time through). */
3183 if (xbitpos % BITS_PER_WORD == 0
3184 || xbitpos == padding_correction)
3186 /* Generate an appropriate register. */
3187 dst = gen_reg_rtx (word_mode);
3188 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3190 /* Clear the destination before we move anything into it. */
3191 emit_move_insn (dst, CONST0_RTX (GET_MODE (dst)));
3194 /* We need a new source operand each time bitpos is on a word
3196 if (bitpos % BITS_PER_WORD == 0)
3197 src = operand_subword_force (result_val,
3198 bitpos / BITS_PER_WORD,
3201 /* Use bitpos for the source extraction (left justified) and
3202 xbitpos for the destination store (right justified). */
3203 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3204 extract_bit_field (src, bitsize,
3205 bitpos % BITS_PER_WORD, 1,
3206 NULL_RTX, word_mode, word_mode,
3211 tmpmode = GET_MODE (result_rtl);
3212 if (tmpmode == BLKmode)
3214 /* Find the smallest integer mode large enough to hold the
3215 entire structure and use that mode instead of BLKmode
3216 on the USE insn for the return register. */
3217 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3218 tmpmode != VOIDmode;
3219 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3220 /* Have we found a large enough mode? */
3221 if (GET_MODE_SIZE (tmpmode) >= bytes)
3224 /* No suitable mode found. */
3225 if (tmpmode == VOIDmode)
3228 PUT_MODE (result_rtl, tmpmode);
3231 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3232 result_reg_mode = word_mode;
3234 result_reg_mode = tmpmode;
3235 result_reg = gen_reg_rtx (result_reg_mode);
3238 for (i = 0; i < n_regs; i++)
3239 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3242 if (tmpmode != result_reg_mode)
3243 result_reg = gen_lowpart (tmpmode, result_reg);
3245 expand_value_return (result_reg);
3247 else if (retval_rhs != 0
3248 && !VOID_TYPE_P (TREE_TYPE (retval_rhs))
3249 && (GET_CODE (result_rtl) == REG
3250 || (GET_CODE (result_rtl) == PARALLEL)))
3252 /* Calculate the return value into a temporary (usually a pseudo
3254 tree ot = TREE_TYPE (DECL_RESULT (current_function_decl));
3255 tree nt = build_qualified_type (ot, TYPE_QUALS (ot) | TYPE_QUAL_CONST);
3257 val = assign_temp (nt, 0, 0, 1);
3258 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3259 val = force_not_mem (val);
3261 /* Return the calculated value, doing cleanups first. */
3262 expand_value_return (shift_return_value (val));
3266 /* No cleanups or no hard reg used;
3267 calculate value into hard return reg. */
3268 expand_expr (retval, const0_rtx, VOIDmode, 0);
3270 expand_value_return (result_rtl);
3274 /* Attempt to optimize a potential tail recursion call into a goto.
3275 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3276 where to place the jump to the tail recursion label.
3278 Return TRUE if the call was optimized into a goto. */
3281 optimize_tail_recursion (tree arguments, rtx last_insn)
3283 /* Finish checking validity, and if valid emit code to set the
3284 argument variables for the new call. */
3285 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3287 if (tail_recursion_label == 0)
3289 tail_recursion_label = gen_label_rtx ();
3290 emit_label_after (tail_recursion_label,
3291 tail_recursion_reentry);
3294 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3301 /* Emit code to alter this function's formal parms for a tail-recursive call.
3302 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3303 FORMALS is the chain of decls of formals.
3304 Return 1 if this can be done;
3305 otherwise return 0 and do not emit any code. */
3308 tail_recursion_args (tree actuals, tree formals)
3310 tree a = actuals, f = formals;
3314 /* Check that number and types of actuals are compatible
3315 with the formals. This is not always true in valid C code.
3316 Also check that no formal needs to be addressable
3317 and that all formals are scalars. */
3319 /* Also count the args. */
3321 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3323 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3324 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3326 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3329 if (a != 0 || f != 0)
3332 /* Compute all the actuals. */
3334 argvec = alloca (i * sizeof (rtx));
3336 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3337 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3339 /* Find which actual values refer to current values of previous formals.
3340 Copy each of them now, before any formal is changed. */
3342 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3346 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3347 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3353 argvec[i] = copy_to_reg (argvec[i]);
3356 /* Store the values of the actuals into the formals. */
3358 for (f = formals, a = actuals, i = 0; f;
3359 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3361 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3362 emit_move_insn (DECL_RTL (f), argvec[i]);
3365 rtx tmp = argvec[i];
3366 int unsignedp = TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a)));
3367 promote_mode(TREE_TYPE (TREE_VALUE (a)), GET_MODE (tmp),
3369 if (DECL_MODE (f) != GET_MODE (DECL_RTL (f)))
3371 tmp = gen_reg_rtx (DECL_MODE (f));
3372 convert_move (tmp, argvec[i], unsignedp);
3374 convert_move (DECL_RTL (f), tmp, unsignedp);
3382 /* Generate the RTL code for entering a binding contour.
3383 The variables are declared one by one, by calls to `expand_decl'.
3385 FLAGS is a bitwise or of the following flags:
3387 1 - Nonzero if this construct should be visible to
3390 2 - Nonzero if this contour does not require a
3391 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3392 language-independent code should set this flag because they
3393 will not create corresponding BLOCK nodes. (There should be
3394 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3395 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3396 when expand_end_bindings is called.
3398 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3399 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3403 expand_start_bindings_and_block (int flags, tree block)
3405 struct nesting *thisblock = ALLOC_NESTING ();
3407 int exit_flag = ((flags & 1) != 0);
3408 int block_flag = ((flags & 2) == 0);
3410 /* If a BLOCK is supplied, then the caller should be requesting a
3411 NOTE_INSN_BLOCK_BEG note. */
3412 if (!block_flag && block)
3415 /* Create a note to mark the beginning of the block. */
3418 note = emit_note (NOTE_INSN_BLOCK_BEG);
3419 NOTE_BLOCK (note) = block;
3422 note = emit_note (NOTE_INSN_DELETED);
3424 /* Make an entry on block_stack for the block we are entering. */
3426 thisblock->desc = BLOCK_NESTING;
3427 thisblock->next = block_stack;
3428 thisblock->all = nesting_stack;
3429 thisblock->depth = ++nesting_depth;
3430 thisblock->data.block.stack_level = 0;
3431 thisblock->data.block.cleanups = 0;
3432 thisblock->data.block.exception_region = 0;
3433 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3435 thisblock->data.block.conditional_code = 0;
3436 thisblock->data.block.last_unconditional_cleanup = note;
3437 /* When we insert instructions after the last unconditional cleanup,
3438 we don't adjust last_insn. That means that a later add_insn will
3439 clobber the instructions we've just added. The easiest way to
3440 fix this is to just insert another instruction here, so that the
3441 instructions inserted after the last unconditional cleanup are
3442 never the last instruction. */
3443 emit_note (NOTE_INSN_DELETED);
3446 && !(block_stack->data.block.cleanups == NULL_TREE
3447 && block_stack->data.block.outer_cleanups == NULL_TREE))
3448 thisblock->data.block.outer_cleanups
3449 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3450 block_stack->data.block.outer_cleanups);
3452 thisblock->data.block.outer_cleanups = 0;
3453 thisblock->data.block.label_chain = 0;
3454 thisblock->data.block.innermost_stack_block = stack_block_stack;
3455 thisblock->data.block.first_insn = note;
3456 thisblock->data.block.block_start_count = ++current_block_start_count;
3457 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3458 block_stack = thisblock;
3459 nesting_stack = thisblock;
3461 /* Make a new level for allocating stack slots. */
3465 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3466 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3467 expand_expr are made. After we end the region, we know that all
3468 space for all temporaries that were created by TARGET_EXPRs will be
3469 destroyed and their space freed for reuse. */
3472 expand_start_target_temps (void)
3474 /* This is so that even if the result is preserved, the space
3475 allocated will be freed, as we know that it is no longer in use. */
3478 /* Start a new binding layer that will keep track of all cleanup
3479 actions to be performed. */
3480 expand_start_bindings (2);
3482 target_temp_slot_level = temp_slot_level;
3486 expand_end_target_temps (void)
3488 expand_end_bindings (NULL_TREE, 0, 0);
3490 /* This is so that even if the result is preserved, the space
3491 allocated will be freed, as we know that it is no longer in use. */
3495 /* Given a pointer to a BLOCK node return nonzero if (and only if) the node
3496 in question represents the outermost pair of curly braces (i.e. the "body
3497 block") of a function or method.
3499 For any BLOCK node representing a "body block" of a function or method, the
3500 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3501 represents the outermost (function) scope for the function or method (i.e.
3502 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3503 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3506 is_body_block (tree stmt)
3508 if (lang_hooks.no_body_blocks)
3511 if (TREE_CODE (stmt) == BLOCK)
3513 tree parent = BLOCK_SUPERCONTEXT (stmt);
3515 if (parent && TREE_CODE (parent) == BLOCK)
3517 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3519 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3527 /* True if we are currently emitting insns in an area of output code
3528 that is controlled by a conditional expression. This is used by
3529 the cleanup handling code to generate conditional cleanup actions. */
3532 conditional_context (void)
3534 return block_stack && block_stack->data.block.conditional_code;
3537 /* Return an opaque pointer to the current nesting level, so frontend code
3538 can check its own sanity. */
3541 current_nesting_level (void)
3543 return cfun ? block_stack : 0;
3546 /* Emit a handler label for a nonlocal goto handler.
3547 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3550 expand_nl_handler_label (rtx slot, rtx before_insn)
3553 rtx handler_label = gen_label_rtx ();
3555 /* Don't let cleanup_cfg delete the handler. */
3556 LABEL_PRESERVE_P (handler_label) = 1;
3559 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3560 insns = get_insns ();
3562 emit_insn_before (insns, before_insn);
3564 emit_label (handler_label);
3566 return handler_label;
3569 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3572 expand_nl_goto_receiver (void)
3574 /* Clobber the FP when we get here, so we have to make sure it's
3575 marked as used by this function. */
3576 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
3578 /* Mark the static chain as clobbered here so life information
3579 doesn't get messed up for it. */
3580 emit_insn (gen_rtx_CLOBBER (VOIDmode, static_chain_rtx));
3582 #ifdef HAVE_nonlocal_goto
3583 if (! HAVE_nonlocal_goto)
3585 /* First adjust our frame pointer to its actual value. It was
3586 previously set to the start of the virtual area corresponding to
3587 the stacked variables when we branched here and now needs to be
3588 adjusted to the actual hardware fp value.
3590 Assignments are to virtual registers are converted by
3591 instantiate_virtual_regs into the corresponding assignment
3592 to the underlying register (fp in this case) that makes
3593 the original assignment true.
3594 So the following insn will actually be
3595 decrementing fp by STARTING_FRAME_OFFSET. */
3596 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3598 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3599 if (fixed_regs[ARG_POINTER_REGNUM])
3601 #ifdef ELIMINABLE_REGS
3602 /* If the argument pointer can be eliminated in favor of the
3603 frame pointer, we don't need to restore it. We assume here
3604 that if such an elimination is present, it can always be used.
3605 This is the case on all known machines; if we don't make this
3606 assumption, we do unnecessary saving on many machines. */
3607 static const struct elims {const int from, to;} elim_regs[] = ELIMINABLE_REGS;
3610 for (i = 0; i < ARRAY_SIZE (elim_regs); i++)
3611 if (elim_regs[i].from == ARG_POINTER_REGNUM
3612 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3615 if (i == ARRAY_SIZE (elim_regs))
3618 /* Now restore our arg pointer from the address at which it
3619 was saved in our stack frame. */
3620 emit_move_insn (virtual_incoming_args_rtx,
3621 copy_to_reg (get_arg_pointer_save_area (cfun)));
3626 #ifdef HAVE_nonlocal_goto_receiver
3627 if (HAVE_nonlocal_goto_receiver)
3628 emit_insn (gen_nonlocal_goto_receiver ());
3631 /* @@@ This is a kludge. Not all machine descriptions define a blockage
3632 insn, but we must not allow the code we just generated to be reordered
3633 by scheduling. Specifically, the update of the frame pointer must
3634 happen immediately, not later. So emit an ASM_INPUT to act as blockage
3636 emit_insn (gen_rtx_ASM_INPUT (VOIDmode, ""));
3639 /* Make handlers for nonlocal gotos taking place in the function calls in
3643 expand_nl_goto_receivers (struct nesting *thisblock)
3646 rtx afterward = gen_label_rtx ();
3651 /* Record the handler address in the stack slot for that purpose,
3652 during this block, saving and restoring the outer value. */
3653 if (thisblock->next != 0)
3654 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3656 rtx save_receiver = gen_reg_rtx (Pmode);
3657 emit_move_insn (XEXP (slot, 0), save_receiver);
3660 emit_move_insn (save_receiver, XEXP (slot, 0));
3661 insns = get_insns ();
3663 emit_insn_before (insns, thisblock->data.block.first_insn);
3666 /* Jump around the handlers; they run only when specially invoked. */
3667 emit_jump (afterward);
3669 /* Make a separate handler for each label. */
3670 link = nonlocal_labels;
3671 slot = nonlocal_goto_handler_slots;
3672 label_list = NULL_RTX;
3673 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3674 /* Skip any labels we shouldn't be able to jump to from here,
3675 we generate one special handler for all of them below which just calls
3677 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3680 lab = expand_nl_handler_label (XEXP (slot, 0),
3681 thisblock->data.block.first_insn);
3682 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3684 expand_nl_goto_receiver ();
3686 /* Jump to the "real" nonlocal label. */
3687 expand_goto (TREE_VALUE (link));
3690 /* A second pass over all nonlocal labels; this time we handle those
3691 we should not be able to jump to at this point. */
3692 link = nonlocal_labels;
3693 slot = nonlocal_goto_handler_slots;
3695 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3696 if (DECL_TOO_LATE (TREE_VALUE (link)))
3699 lab = expand_nl_handler_label (XEXP (slot, 0),
3700 thisblock->data.block.first_insn);
3701 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3707 expand_nl_goto_receiver ();
3708 expand_builtin_trap ();
3711 nonlocal_goto_handler_labels = label_list;
3712 emit_label (afterward);
3715 /* Warn about any unused VARS (which may contain nodes other than
3716 VAR_DECLs, but such nodes are ignored). The nodes are connected
3717 via the TREE_CHAIN field. */
3720 warn_about_unused_variables (tree vars)
3724 if (warn_unused_variable)
3725 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3726 if (TREE_CODE (decl) == VAR_DECL
3727 && ! TREE_USED (decl)
3728 && ! DECL_IN_SYSTEM_HEADER (decl)
3729 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3730 warning ("%Junused variable '%D'", decl, decl);
3733 /* Generate RTL code to terminate a binding contour.
3735 VARS is the chain of VAR_DECL nodes for the variables bound in this
3736 contour. There may actually be other nodes in this chain, but any
3737 nodes other than VAR_DECLS are ignored.
3739 MARK_ENDS is nonzero if we should put a note at the beginning
3740 and end of this binding contour.
3742 DONT_JUMP_IN is positive if it is not valid to jump into this contour,
3743 zero if we can jump into this contour only if it does not have a saved
3744 stack level, and negative if we are not to check for invalid use of
3745 labels (because the front end does that). */
3748 expand_end_bindings (tree vars, int mark_ends, int dont_jump_in)
3750 struct nesting *thisblock = block_stack;
3752 /* If any of the variables in this scope were not used, warn the
3754 warn_about_unused_variables (vars);
3756 if (thisblock->exit_label)
3758 do_pending_stack_adjust ();
3759 emit_label (thisblock->exit_label);
3762 /* If necessary, make handlers for nonlocal gotos taking
3763 place in the function calls in this block. */
3764 if (function_call_count != 0 && nonlocal_labels
3765 /* Make handler for outermost block
3766 if there were any nonlocal gotos to this function. */
3767 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3768 /* Make handler for inner block if it has something
3769 special to do when you jump out of it. */
3770 : (thisblock->data.block.cleanups != 0
3771 || thisblock->data.block.stack_level != 0)))
3772 expand_nl_goto_receivers (thisblock);
3774 /* Don't allow jumping into a block that has a stack level.
3775 Cleanups are allowed, though. */
3776 if (dont_jump_in > 0
3777 || (dont_jump_in == 0 && thisblock->data.block.stack_level != 0))
3779 struct label_chain *chain;
3781 /* Any labels in this block are no longer valid to go to.
3782 Mark them to cause an error message. */
3783 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3785 DECL_TOO_LATE (chain->label) = 1;
3786 /* If any goto without a fixup came to this label,
3787 that must be an error, because gotos without fixups
3788 come from outside all saved stack-levels. */
3789 if (TREE_ADDRESSABLE (chain->label))
3790 error ("%Jlabel '%D' used before containing binding contour",
3791 chain->label, chain->label);
3795 /* Restore stack level in effect before the block
3796 (only if variable-size objects allocated). */
3797 /* Perform any cleanups associated with the block. */
3799 if (thisblock->data.block.stack_level != 0
3800 || thisblock->data.block.cleanups != 0)
3805 /* Don't let cleanups affect ({...}) constructs. */
3806 int old_expr_stmts_for_value = expr_stmts_for_value;
3807 rtx old_last_expr_value = last_expr_value;
3808 rtx old_last_expr_alt_rtl = last_expr_alt_rtl;
3809 tree old_last_expr_type = last_expr_type;
3810 expr_stmts_for_value = 0;
3812 /* Only clean up here if this point can actually be reached. */
3813 insn = get_last_insn ();
3814 if (GET_CODE (insn) == NOTE)
3815 insn = prev_nonnote_insn (insn);
3816 reachable = (! insn || GET_CODE (insn) != BARRIER);
3818 /* Do the cleanups. */
3819 expand_cleanups (thisblock->data.block.cleanups, 0, reachable);
3821 do_pending_stack_adjust ();
3823 expr_stmts_for_value = old_expr_stmts_for_value;
3824 last_expr_value = old_last_expr_value;
3825 last_expr_alt_rtl = old_last_expr_alt_rtl;
3826 last_expr_type = old_last_expr_type;
3828 /* Restore the stack level. */
3830 if (reachable && thisblock->data.block.stack_level != 0)
3832 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3833 thisblock->data.block.stack_level, NULL_RTX);
3834 if (nonlocal_goto_handler_slots != 0)
3835 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3839 /* Any gotos out of this block must also do these things.
3840 Also report any gotos with fixups that came to labels in this
3842 fixup_gotos (thisblock,
3843 thisblock->data.block.stack_level,
3844 thisblock->data.block.cleanups,
3845 thisblock->data.block.first_insn,
3849 /* Mark the beginning and end of the scope if requested.
3850 We do this now, after running cleanups on the variables
3851 just going out of scope, so they are in scope for their cleanups. */
3855 rtx note = emit_note (NOTE_INSN_BLOCK_END);
3856 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3859 /* Get rid of the beginning-mark if we don't make an end-mark. */
3860 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3862 /* Restore the temporary level of TARGET_EXPRs. */
3863 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3865 /* Restore block_stack level for containing block. */
3867 stack_block_stack = thisblock->data.block.innermost_stack_block;
3868 POPSTACK (block_stack);
3870 /* Pop the stack slot nesting and free any slots at this level. */
3874 /* Generate code to save the stack pointer at the start of the current block
3875 and set up to restore it on exit. */
3878 save_stack_pointer (void)
3880 struct nesting *thisblock = block_stack;
3882 if (thisblock->data.block.stack_level == 0)
3884 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3885 &thisblock->data.block.stack_level,
3886 thisblock->data.block.first_insn);
3887 stack_block_stack = thisblock;
3891 /* Generate RTL for the automatic variable declaration DECL.
3892 (Other kinds of declarations are simply ignored if seen here.) */
3895 expand_decl (tree decl)
3899 type = TREE_TYPE (decl);
3901 /* For a CONST_DECL, set mode, alignment, and sizes from those of the
3902 type in case this node is used in a reference. */
3903 if (TREE_CODE (decl) == CONST_DECL)
3905 DECL_MODE (decl) = TYPE_MODE (type);
3906 DECL_ALIGN (decl) = TYPE_ALIGN (type);
3907 DECL_SIZE (decl) = TYPE_SIZE (type);
3908 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
3912 /* Otherwise, only automatic variables need any expansion done. Static and
3913 external variables, and external functions, will be handled by
3914 `assemble_variable' (called from finish_decl). TYPE_DECL requires
3915 nothing. PARM_DECLs are handled in `assign_parms'. */
3916 if (TREE_CODE (decl) != VAR_DECL)
3919 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3922 /* Create the RTL representation for the variable. */
3924 if (type == error_mark_node)
3925 SET_DECL_RTL (decl, gen_rtx_MEM (BLKmode, const0_rtx));
3927 else if (DECL_SIZE (decl) == 0)
3928 /* Variable with incomplete type. */
3931 if (DECL_INITIAL (decl) == 0)
3932 /* Error message was already done; now avoid a crash. */
3933 x = gen_rtx_MEM (BLKmode, const0_rtx);
3935 /* An initializer is going to decide the size of this array.
3936 Until we know the size, represent its address with a reg. */
3937 x = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3939 set_mem_attributes (x, decl, 1);
3940 SET_DECL_RTL (decl, x);
3942 else if (DECL_MODE (decl) != BLKmode
3943 /* If -ffloat-store, don't put explicit float vars
3945 && !(flag_float_store
3946 && TREE_CODE (type) == REAL_TYPE)
3947 && ! TREE_THIS_VOLATILE (decl)
3948 && ! DECL_NONLOCAL (decl)
3949 && (DECL_REGISTER (decl) || DECL_ARTIFICIAL (decl) || optimize))
3951 /* Automatic variable that can go in a register. */
3952 int unsignedp = TREE_UNSIGNED (type);
3953 enum machine_mode reg_mode
3954 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3956 SET_DECL_RTL (decl, gen_reg_rtx (reg_mode));
3958 if (!DECL_ARTIFICIAL (decl))
3959 mark_user_reg (DECL_RTL (decl));
3961 if (POINTER_TYPE_P (type))
3962 mark_reg_pointer (DECL_RTL (decl),
3963 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3965 maybe_set_unchanging (DECL_RTL (decl), decl);
3967 /* If something wants our address, try to use ADDRESSOF. */
3968 if (TREE_ADDRESSABLE (decl))
3969 put_var_into_stack (decl, /*rescan=*/false);
3972 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3973 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3974 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3975 STACK_CHECK_MAX_VAR_SIZE)))
3977 /* Variable of fixed size that goes on the stack. */
3982 /* If we previously made RTL for this decl, it must be an array
3983 whose size was determined by the initializer.
3984 The old address was a register; set that register now
3985 to the proper address. */
3986 if (DECL_RTL_SET_P (decl))
3988 if (GET_CODE (DECL_RTL (decl)) != MEM
3989 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3991 oldaddr = XEXP (DECL_RTL (decl), 0);
3994 /* Set alignment we actually gave this decl. */
3995 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3996 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3997 DECL_USER_ALIGN (decl) = 0;
3999 x = assign_temp (decl, 1, 1, 1);
4000 set_mem_attributes (x, decl, 1);
4001 SET_DECL_RTL (decl, x);
4005 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
4006 if (addr != oldaddr)
4007 emit_move_insn (oldaddr, addr);
4011 /* Dynamic-size object: must push space on the stack. */
4013 rtx address, size, x;
4015 /* Record the stack pointer on entry to block, if have
4016 not already done so. */
4017 do_pending_stack_adjust ();
4018 save_stack_pointer ();
4020 /* In function-at-a-time mode, variable_size doesn't expand this,
4022 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
4023 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
4024 const0_rtx, VOIDmode, 0);
4026 /* Compute the variable's size, in bytes. */
4027 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
4030 /* Allocate space on the stack for the variable. Note that
4031 DECL_ALIGN says how the variable is to be aligned and we
4032 cannot use it to conclude anything about the alignment of
4034 address = allocate_dynamic_stack_space (size, NULL_RTX,
4035 TYPE_ALIGN (TREE_TYPE (decl)));
4037 /* Reference the variable indirect through that rtx. */
4038 x = gen_rtx_MEM (DECL_MODE (decl), address);
4039 set_mem_attributes (x, decl, 1);
4040 SET_DECL_RTL (decl, x);
4043 /* Indicate the alignment we actually gave this variable. */
4044 #ifdef STACK_BOUNDARY
4045 DECL_ALIGN (decl) = STACK_BOUNDARY;
4047 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
4049 DECL_USER_ALIGN (decl) = 0;
4053 /* Emit code to perform the initialization of a declaration DECL. */
4056 expand_decl_init (tree decl)
4058 int was_used = TREE_USED (decl);
4060 /* If this is a CONST_DECL, we don't have to generate any code. Likewise
4061 for static decls. */
4062 if (TREE_CODE (decl) == CONST_DECL
4063 || TREE_STATIC (decl))
4066 /* Compute and store the initial value now. */
4070 if (DECL_INITIAL (decl) == error_mark_node)
4072 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
4074 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
4075 || code == POINTER_TYPE || code == REFERENCE_TYPE)
4076 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
4080 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
4082 emit_line_note (DECL_SOURCE_LOCATION (decl));
4083 expand_assignment (decl, DECL_INITIAL (decl), 0);
4087 /* Don't let the initialization count as "using" the variable. */
4088 TREE_USED (decl) = was_used;
4090 /* Free any temporaries we made while initializing the decl. */
4091 preserve_temp_slots (NULL_RTX);
4096 /* CLEANUP is an expression to be executed at exit from this binding contour;
4097 for example, in C++, it might call the destructor for this variable.
4099 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
4100 CLEANUP multiple times, and have the correct semantics. This
4101 happens in exception handling, for gotos, returns, breaks that
4102 leave the current scope.
4104 If CLEANUP is nonzero and DECL is zero, we record a cleanup
4105 that is not associated with any particular variable. */
4108 expand_decl_cleanup (tree decl, tree cleanup)
4110 struct nesting *thisblock;
4112 /* Error if we are not in any block. */
4113 if (cfun == 0 || block_stack == 0)
4116 thisblock = block_stack;
4118 /* Record the cleanup if there is one. */
4124 tree *cleanups = &thisblock->data.block.cleanups;
4125 int cond_context = conditional_context ();
4129 rtx flag = gen_reg_rtx (word_mode);
4134 emit_move_insn (flag, const0_rtx);
4135 set_flag_0 = get_insns ();
4138 thisblock->data.block.last_unconditional_cleanup
4139 = emit_insn_after (set_flag_0,
4140 thisblock->data.block.last_unconditional_cleanup);
4142 emit_move_insn (flag, const1_rtx);
4144 cond = build_decl (VAR_DECL, NULL_TREE,
4145 (*lang_hooks.types.type_for_mode) (word_mode, 1));
4146 SET_DECL_RTL (cond, flag);
4148 /* Conditionalize the cleanup. */
4149 cleanup = build (COND_EXPR, void_type_node,
4150 (*lang_hooks.truthvalue_conversion) (cond),
4151 cleanup, integer_zero_node);
4152 cleanup = fold (cleanup);
4154 cleanups = &thisblock->data.block.cleanups;
4157 cleanup = unsave_expr (cleanup);
4159 t = *cleanups = tree_cons (decl, cleanup, *cleanups);
4162 /* If this block has a cleanup, it belongs in stack_block_stack. */
4163 stack_block_stack = thisblock;
4170 if (! using_eh_for_cleanups_p)
4171 TREE_ADDRESSABLE (t) = 1;
4173 expand_eh_region_start ();
4180 thisblock->data.block.last_unconditional_cleanup
4181 = emit_insn_after (seq,
4182 thisblock->data.block.last_unconditional_cleanup);
4186 thisblock->data.block.last_unconditional_cleanup
4188 /* When we insert instructions after the last unconditional cleanup,
4189 we don't adjust last_insn. That means that a later add_insn will
4190 clobber the instructions we've just added. The easiest way to
4191 fix this is to just insert another instruction here, so that the
4192 instructions inserted after the last unconditional cleanup are
4193 never the last instruction. */
4194 emit_note (NOTE_INSN_DELETED);
4200 /* Like expand_decl_cleanup, but maybe only run the cleanup if an exception
4204 expand_decl_cleanup_eh (tree decl, tree cleanup, int eh_only)
4206 int ret = expand_decl_cleanup (decl, cleanup);
4209 tree node = block_stack->data.block.cleanups;
4210 CLEANUP_EH_ONLY (node) = eh_only;
4215 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4216 DECL_ELTS is the list of elements that belong to DECL's type.
4217 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4220 expand_anon_union_decl (tree decl, tree cleanup, tree decl_elts)
4222 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4226 /* If any of the elements are addressable, so is the entire union. */
4227 for (t = decl_elts; t; t = TREE_CHAIN (t))
4228 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4230 TREE_ADDRESSABLE (decl) = 1;
4235 expand_decl_cleanup (decl, cleanup);
4236 x = DECL_RTL (decl);
4238 /* Go through the elements, assigning RTL to each. */
4239 for (t = decl_elts; t; t = TREE_CHAIN (t))
4241 tree decl_elt = TREE_VALUE (t);
4242 tree cleanup_elt = TREE_PURPOSE (t);
4243 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4245 /* If any of the elements are addressable, so is the entire
4247 if (TREE_USED (decl_elt))
4248 TREE_USED (decl) = 1;
4250 /* Propagate the union's alignment to the elements. */
4251 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4252 DECL_USER_ALIGN (decl_elt) = DECL_USER_ALIGN (decl);
4254 /* If the element has BLKmode and the union doesn't, the union is
4255 aligned such that the element doesn't need to have BLKmode, so
4256 change the element's mode to the appropriate one for its size. */
4257 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4258 DECL_MODE (decl_elt) = mode
4259 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4261 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4262 instead create a new MEM rtx with the proper mode. */
4263 if (GET_CODE (x) == MEM)
4265 if (mode == GET_MODE (x))
4266 SET_DECL_RTL (decl_elt, x);
4268 SET_DECL_RTL (decl_elt, adjust_address_nv (x, mode, 0));
4270 else if (GET_CODE (x) == REG)
4272 if (mode == GET_MODE (x))
4273 SET_DECL_RTL (decl_elt, x);
4275 SET_DECL_RTL (decl_elt, gen_lowpart_SUBREG (mode, x));
4280 /* Record the cleanup if there is one. */
4283 thisblock->data.block.cleanups
4284 = tree_cons (decl_elt, cleanup_elt,
4285 thisblock->data.block.cleanups);
4289 /* Expand a list of cleanups LIST.
4290 Elements may be expressions or may be nested lists.
4292 If IN_FIXUP is nonzero, we are generating this cleanup for a fixup
4293 goto and handle protection regions specially in that case.
4295 If REACHABLE, we emit code, otherwise just inform the exception handling
4296 code about this finalization. */
4299 expand_cleanups (tree list, int in_fixup, int reachable)
4302 for (tail = list; tail; tail = TREE_CHAIN (tail))
4303 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4304 expand_cleanups (TREE_VALUE (tail), in_fixup, reachable);
4307 if (! in_fixup && using_eh_for_cleanups_p)
4308 expand_eh_region_end_cleanup (TREE_VALUE (tail));
4310 if (reachable && !CLEANUP_EH_ONLY (tail))
4312 /* Cleanups may be run multiple times. For example,
4313 when exiting a binding contour, we expand the
4314 cleanups associated with that contour. When a goto
4315 within that binding contour has a target outside that
4316 contour, it will expand all cleanups from its scope to
4317 the target. Though the cleanups are expanded multiple
4318 times, the control paths are non-overlapping so the
4319 cleanups will not be executed twice. */
4321 /* We may need to protect from outer cleanups. */
4322 if (in_fixup && using_eh_for_cleanups_p)
4324 expand_eh_region_start ();
4326 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4328 expand_eh_region_end_fixup (TREE_VALUE (tail));
4331 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4338 /* Mark when the context we are emitting RTL for as a conditional
4339 context, so that any cleanup actions we register with
4340 expand_decl_init will be properly conditionalized when those
4341 cleanup actions are later performed. Must be called before any
4342 expression (tree) is expanded that is within a conditional context. */
4345 start_cleanup_deferral (void)
4347 /* block_stack can be NULL if we are inside the parameter list. It is
4348 OK to do nothing, because cleanups aren't possible here. */
4350 ++block_stack->data.block.conditional_code;
4353 /* Mark the end of a conditional region of code. Because cleanup
4354 deferrals may be nested, we may still be in a conditional region
4355 after we end the currently deferred cleanups, only after we end all
4356 deferred cleanups, are we back in unconditional code. */
4359 end_cleanup_deferral (void)
4361 /* block_stack can be NULL if we are inside the parameter list. It is
4362 OK to do nothing, because cleanups aren't possible here. */
4364 --block_stack->data.block.conditional_code;
4368 last_cleanup_this_contour (void)
4370 if (block_stack == 0)
4373 return block_stack->data.block.cleanups;
4376 /* Return 1 if there are any pending cleanups at this point.
4377 Check the current contour as well as contours that enclose
4378 the current contour. */
4381 any_pending_cleanups (void)
4383 struct nesting *block;
4385 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4388 if (block_stack->data.block.cleanups != NULL)
4391 if (block_stack->data.block.outer_cleanups == 0)
4394 for (block = block_stack->next; block; block = block->next)
4395 if (block->data.block.cleanups != 0)
4401 /* Enter a case (Pascal) or switch (C) statement.
4402 Push a block onto case_stack and nesting_stack
4403 to accumulate the case-labels that are seen
4404 and to record the labels generated for the statement.
4406 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4407 Otherwise, this construct is transparent for `exit_something'.
4409 EXPR is the index-expression to be dispatched on.
4410 TYPE is its nominal type. We could simply convert EXPR to this type,
4411 but instead we take short cuts. */
4414 expand_start_case (int exit_flag, tree expr, tree type,
4415 const char *printname)
4417 struct nesting *thiscase = ALLOC_NESTING ();
4419 /* Make an entry on case_stack for the case we are entering. */
4421 thiscase->desc = CASE_NESTING;
4422 thiscase->next = case_stack;
4423 thiscase->all = nesting_stack;
4424 thiscase->depth = ++nesting_depth;
4425 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4426 thiscase->data.case_stmt.case_list = 0;
4427 thiscase->data.case_stmt.index_expr = expr;
4428 thiscase->data.case_stmt.nominal_type = type;
4429 thiscase->data.case_stmt.default_label = 0;
4430 thiscase->data.case_stmt.printname = printname;
4431 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4432 case_stack = thiscase;
4433 nesting_stack = thiscase;
4435 do_pending_stack_adjust ();
4438 /* Make sure case_stmt.start points to something that won't
4439 need any transformation before expand_end_case. */
4440 if (GET_CODE (get_last_insn ()) != NOTE)
4441 emit_note (NOTE_INSN_DELETED);
4443 thiscase->data.case_stmt.start = get_last_insn ();
4445 start_cleanup_deferral ();
4448 /* Start a "dummy case statement" within which case labels are invalid
4449 and are not connected to any larger real case statement.
4450 This can be used if you don't want to let a case statement jump
4451 into the middle of certain kinds of constructs. */
4454 expand_start_case_dummy (void)
4456 struct nesting *thiscase = ALLOC_NESTING ();
4458 /* Make an entry on case_stack for the dummy. */
4460 thiscase->desc = CASE_NESTING;
4461 thiscase->next = case_stack;
4462 thiscase->all = nesting_stack;
4463 thiscase->depth = ++nesting_depth;
4464 thiscase->exit_label = 0;
4465 thiscase->data.case_stmt.case_list = 0;
4466 thiscase->data.case_stmt.start = 0;
4467 thiscase->data.case_stmt.nominal_type = 0;
4468 thiscase->data.case_stmt.default_label = 0;
4469 case_stack = thiscase;
4470 nesting_stack = thiscase;
4471 start_cleanup_deferral ();
4475 check_seenlabel (void)
4477 /* If this is the first label, warn if any insns have been emitted. */
4478 if (case_stack->data.case_stmt.line_number_status >= 0)
4482 restore_line_number_status
4483 (case_stack->data.case_stmt.line_number_status);
4484 case_stack->data.case_stmt.line_number_status = -1;
4486 for (insn = case_stack->data.case_stmt.start;
4488 insn = NEXT_INSN (insn))
4490 if (GET_CODE (insn) == CODE_LABEL)
4492 if (GET_CODE (insn) != NOTE
4493 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4496 insn = PREV_INSN (insn);
4497 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4499 /* If insn is zero, then there must have been a syntax error. */
4503 locus.file = NOTE_SOURCE_FILE (insn);
4504 locus.line = NOTE_LINE_NUMBER (insn);
4505 warning ("%Hunreachable code at beginning of %s", &locus,
4506 case_stack->data.case_stmt.printname);
4514 /* Accumulate one case or default label inside a case or switch statement.
4515 VALUE is the value of the case (a null pointer, for a default label).
4516 The function CONVERTER, when applied to arguments T and V,
4517 converts the value V to the type T.
4519 If not currently inside a case or switch statement, return 1 and do
4520 nothing. The caller will print a language-specific error message.
4521 If VALUE is a duplicate or overlaps, return 2 and do nothing
4522 except store the (first) duplicate node in *DUPLICATE.
4523 If VALUE is out of range, return 3 and do nothing.
4524 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4525 Return 0 on success.
4527 Extended to handle range statements. */
4530 pushcase (tree value, tree (*converter) (tree, tree), tree label,
4536 /* Fail if not inside a real case statement. */
4537 if (! (case_stack && case_stack->data.case_stmt.start))
4540 if (stack_block_stack
4541 && stack_block_stack->depth > case_stack->depth)
4544 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4545 nominal_type = case_stack->data.case_stmt.nominal_type;
4547 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4548 if (index_type == error_mark_node)
4551 /* Convert VALUE to the type in which the comparisons are nominally done. */
4553 value = (*converter) (nominal_type, value);
4557 /* Fail if this value is out of range for the actual type of the index
4558 (which may be narrower than NOMINAL_TYPE). */
4560 && (TREE_CONSTANT_OVERFLOW (value)
4561 || ! int_fits_type_p (value, index_type)))
4564 return add_case_node (value, value, label, duplicate);
4567 /* Like pushcase but this case applies to all values between VALUE1 and
4568 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4569 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4570 starts at VALUE1 and ends at the highest value of the index type.
4571 If both are NULL, this case applies to all values.
4573 The return value is the same as that of pushcase but there is one
4574 additional error code: 4 means the specified range was empty. */
4577 pushcase_range (tree value1, tree value2, tree (*converter) (tree, tree),
4578 tree label, tree *duplicate)
4583 /* Fail if not inside a real case statement. */
4584 if (! (case_stack && case_stack->data.case_stmt.start))
4587 if (stack_block_stack
4588 && stack_block_stack->depth > case_stack->depth)
4591 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4592 nominal_type = case_stack->data.case_stmt.nominal_type;
4594 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4595 if (index_type == error_mark_node)
4600 /* Convert VALUEs to type in which the comparisons are nominally done
4601 and replace any unspecified value with the corresponding bound. */
4603 value1 = TYPE_MIN_VALUE (index_type);
4605 value2 = TYPE_MAX_VALUE (index_type);
4607 /* Fail if the range is empty. Do this before any conversion since
4608 we want to allow out-of-range empty ranges. */
4609 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4612 /* If the max was unbounded, use the max of the nominal_type we are
4613 converting to. Do this after the < check above to suppress false
4616 value2 = TYPE_MAX_VALUE (nominal_type);
4618 value1 = (*converter) (nominal_type, value1);
4619 value2 = (*converter) (nominal_type, value2);
4621 /* Fail if these values are out of range. */
4622 if (TREE_CONSTANT_OVERFLOW (value1)
4623 || ! int_fits_type_p (value1, index_type))
4626 if (TREE_CONSTANT_OVERFLOW (value2)
4627 || ! int_fits_type_p (value2, index_type))
4630 return add_case_node (value1, value2, label, duplicate);
4633 /* Do the actual insertion of a case label for pushcase and pushcase_range
4634 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4635 slowdown for large switch statements. */
4638 add_case_node (tree low, tree high, tree label, tree *duplicate)
4640 struct case_node *p, **q, *r;
4642 /* If there's no HIGH value, then this is not a case range; it's
4643 just a simple case label. But that's just a degenerate case
4648 /* Handle default labels specially. */
4651 if (case_stack->data.case_stmt.default_label != 0)
4653 *duplicate = case_stack->data.case_stmt.default_label;
4656 case_stack->data.case_stmt.default_label = label;
4657 expand_label (label);
4661 q = &case_stack->data.case_stmt.case_list;
4668 /* Keep going past elements distinctly greater than HIGH. */
4669 if (tree_int_cst_lt (high, p->low))
4672 /* or distinctly less than LOW. */
4673 else if (tree_int_cst_lt (p->high, low))
4678 /* We have an overlap; this is an error. */
4679 *duplicate = p->code_label;
4684 /* Add this label to the chain, and succeed. */
4686 r = ggc_alloc (sizeof (struct case_node));
4689 /* If the bounds are equal, turn this into the one-value case. */
4690 if (tree_int_cst_equal (low, high))
4695 r->code_label = label;
4696 expand_label (label);
4706 struct case_node *s;
4712 if (! (b = p->balance))
4713 /* Growth propagation from left side. */
4720 if ((p->left = s = r->right))
4729 if ((r->parent = s))
4737 case_stack->data.case_stmt.case_list = r;
4740 /* r->balance == +1 */
4745 struct case_node *t = r->right;
4747 if ((p->left = s = t->right))
4751 if ((r->right = s = t->left))
4765 if ((t->parent = s))
4773 case_stack->data.case_stmt.case_list = t;
4780 /* p->balance == +1; growth of left side balances the node. */
4790 if (! (b = p->balance))
4791 /* Growth propagation from right side. */
4799 if ((p->right = s = r->left))
4807 if ((r->parent = s))
4816 case_stack->data.case_stmt.case_list = r;
4820 /* r->balance == -1 */
4824 struct case_node *t = r->left;
4826 if ((p->right = s = t->left))
4831 if ((r->left = s = t->right))
4845 if ((t->parent = s))
4854 case_stack->data.case_stmt.case_list = t;
4860 /* p->balance == -1; growth of right side balances the node. */
4873 /* Returns the number of possible values of TYPE.
4874 Returns -1 if the number is unknown, variable, or if the number does not
4875 fit in a HOST_WIDE_INT.
4876 Sets *SPARSENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4877 do not increase monotonically (there may be duplicates);
4878 to 1 if the values increase monotonically, but not always by 1;
4879 otherwise sets it to 0. */
4882 all_cases_count (tree type, int *sparseness)
4885 HOST_WIDE_INT count, minval, lastval;
4889 switch (TREE_CODE (type))
4896 count = 1 << BITS_PER_UNIT;
4901 if (TYPE_MAX_VALUE (type) != 0
4902 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4903 TYPE_MIN_VALUE (type))))
4904 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4905 convert (type, integer_zero_node))))
4906 && host_integerp (t, 1))
4907 count = tree_low_cst (t, 1);
4913 /* Don't waste time with enumeral types with huge values. */
4914 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4915 || TYPE_MAX_VALUE (type) == 0
4916 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4919 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4922 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4924 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4926 if (*sparseness == 2 || thisval <= lastval)
4928 else if (thisval != minval + count)
4939 #define BITARRAY_TEST(ARRAY, INDEX) \
4940 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4941 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4942 #define BITARRAY_SET(ARRAY, INDEX) \
4943 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4944 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4946 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4947 with the case values we have seen, assuming the case expression
4949 SPARSENESS is as determined by all_cases_count.
4951 The time needed is proportional to COUNT, unless
4952 SPARSENESS is 2, in which case quadratic time is needed. */
4955 mark_seen_cases (tree type, unsigned char *cases_seen, HOST_WIDE_INT count,
4958 tree next_node_to_try = NULL_TREE;
4959 HOST_WIDE_INT next_node_offset = 0;
4961 struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4962 tree val = make_node (INTEGER_CST);
4964 TREE_TYPE (val) = type;
4968 else if (sparseness == 2)
4971 unsigned HOST_WIDE_INT xlo;
4973 /* This less efficient loop is only needed to handle
4974 duplicate case values (multiple enum constants
4975 with the same value). */
4976 TREE_TYPE (val) = TREE_TYPE (root->low);
4977 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4978 t = TREE_CHAIN (t), xlo++)
4980 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
4981 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
4985 /* Keep going past elements distinctly greater than VAL. */
4986 if (tree_int_cst_lt (val, n->low))
4989 /* or distinctly less than VAL. */
4990 else if (tree_int_cst_lt (n->high, val))
4995 /* We have found a matching range. */
4996 BITARRAY_SET (cases_seen, xlo);
5006 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
5008 for (n = root; n; n = n->right)
5010 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
5011 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
5012 while (! tree_int_cst_lt (n->high, val))
5014 /* Calculate (into xlo) the "offset" of the integer (val).
5015 The element with lowest value has offset 0, the next smallest
5016 element has offset 1, etc. */
5018 unsigned HOST_WIDE_INT xlo;
5022 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
5024 /* The TYPE_VALUES will be in increasing order, so
5025 starting searching where we last ended. */
5026 t = next_node_to_try;
5027 xlo = next_node_offset;
5033 t = TYPE_VALUES (type);
5036 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5038 next_node_to_try = TREE_CHAIN (t);
5039 next_node_offset = xlo + 1;
5044 if (t == next_node_to_try)
5053 t = TYPE_MIN_VALUE (type);
5055 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5059 add_double (xlo, xhi,
5060 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5064 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5065 BITARRAY_SET (cases_seen, xlo);
5067 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5069 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5075 /* Given a switch statement with an expression that is an enumeration
5076 type, warn if any of the enumeration type's literals are not
5077 covered by the case expressions of the switch. Also, warn if there
5078 are any extra switch cases that are *not* elements of the
5083 At one stage this function would: ``If all enumeration literals
5084 were covered by the case expressions, turn one of the expressions
5085 into the default expression since it should not be possible to fall
5086 through such a switch.''
5088 That code has since been removed as: ``This optimization is
5089 disabled because it causes valid programs to fail. ANSI C does not
5090 guarantee that an expression with enum type will have a value that
5091 is the same as one of the enumeration literals.'' */
5094 check_for_full_enumeration_handling (tree type)
5096 struct case_node *n;
5099 /* True iff the selector type is a numbered set mode. */
5102 /* The number of possible selector values. */
5105 /* For each possible selector value. a one iff it has been matched
5106 by a case value alternative. */
5107 unsigned char *cases_seen;
5109 /* The allocated size of cases_seen, in chars. */
5110 HOST_WIDE_INT bytes_needed;
5112 size = all_cases_count (type, &sparseness);
5113 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5115 if (size > 0 && size < 600000
5116 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5117 this optimization if we don't have enough memory rather than
5118 aborting, as xmalloc would do. */
5119 && (cases_seen = really_call_calloc (bytes_needed, 1)) != NULL)
5122 tree v = TYPE_VALUES (type);
5124 /* The time complexity of this code is normally O(N), where
5125 N being the number of members in the enumerated type.
5126 However, if type is an ENUMERAL_TYPE whose values do not
5127 increase monotonically, O(N*log(N)) time may be needed. */
5129 mark_seen_cases (type, cases_seen, size, sparseness);
5131 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5132 if (BITARRAY_TEST (cases_seen, i) == 0)
5133 warning ("enumeration value `%s' not handled in switch",
5134 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5139 /* Now we go the other way around; we warn if there are case
5140 expressions that don't correspond to enumerators. This can
5141 occur since C and C++ don't enforce type-checking of
5142 assignments to enumeration variables. */
5144 if (case_stack->data.case_stmt.case_list
5145 && case_stack->data.case_stmt.case_list->left)
5146 case_stack->data.case_stmt.case_list
5147 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5148 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5150 for (chain = TYPE_VALUES (type);
5151 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5152 chain = TREE_CHAIN (chain))
5157 if (TYPE_NAME (type) == 0)
5158 warning ("case value `%ld' not in enumerated type",
5159 (long) TREE_INT_CST_LOW (n->low));
5161 warning ("case value `%ld' not in enumerated type `%s'",
5162 (long) TREE_INT_CST_LOW (n->low),
5163 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5166 : DECL_NAME (TYPE_NAME (type))));
5168 if (!tree_int_cst_equal (n->low, n->high))
5170 for (chain = TYPE_VALUES (type);
5171 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5172 chain = TREE_CHAIN (chain))
5177 if (TYPE_NAME (type) == 0)
5178 warning ("case value `%ld' not in enumerated type",
5179 (long) TREE_INT_CST_LOW (n->high));
5181 warning ("case value `%ld' not in enumerated type `%s'",
5182 (long) TREE_INT_CST_LOW (n->high),
5183 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5186 : DECL_NAME (TYPE_NAME (type))));
5193 /* Maximum number of case bit tests. */
5194 #define MAX_CASE_BIT_TESTS 3
5196 /* By default, enable case bit tests on targets with ashlsi3. */
5197 #ifndef CASE_USE_BIT_TESTS
5198 #define CASE_USE_BIT_TESTS (ashl_optab->handlers[word_mode].insn_code \
5199 != CODE_FOR_nothing)
5203 /* A case_bit_test represents a set of case nodes that may be
5204 selected from using a bit-wise comparison. HI and LO hold
5205 the integer to be tested against, LABEL contains the label
5206 to jump to upon success and BITS counts the number of case
5207 nodes handled by this test, typically the number of bits
5210 struct case_bit_test
5218 /* Determine whether "1 << x" is relatively cheap in word_mode. */
5221 bool lshift_cheap_p (void)
5223 static bool init = false;
5224 static bool cheap = true;
5228 rtx reg = gen_rtx_REG (word_mode, 10000);
5229 int cost = rtx_cost (gen_rtx_ASHIFT (word_mode, const1_rtx, reg), SET);
5230 cheap = cost < COSTS_N_INSNS (3);
5237 /* Comparison function for qsort to order bit tests by decreasing
5238 number of case nodes, i.e. the node with the most cases gets
5242 int case_bit_test_cmp (const void *p1, const void *p2)
5244 const struct case_bit_test *d1 = p1;
5245 const struct case_bit_test *d2 = p2;
5247 return d2->bits - d1->bits;
5250 /* Expand a switch statement by a short sequence of bit-wise
5251 comparisons. "switch(x)" is effectively converted into
5252 "if ((1 << (x-MINVAL)) & CST)" where CST and MINVAL are
5255 INDEX_EXPR is the value being switched on, which is of
5256 type INDEX_TYPE. MINVAL is the lowest case value of in
5257 the case nodes, of INDEX_TYPE type, and RANGE is highest
5258 value minus MINVAL, also of type INDEX_TYPE. NODES is
5259 the set of case nodes, and DEFAULT_LABEL is the label to
5260 branch to should none of the cases match.
5262 There *MUST* be MAX_CASE_BIT_TESTS or less unique case
5266 emit_case_bit_tests (tree index_type, tree index_expr, tree minval,
5267 tree range, case_node_ptr nodes, rtx default_label)
5269 struct case_bit_test test[MAX_CASE_BIT_TESTS];
5270 enum machine_mode mode;
5271 rtx expr, index, label;
5272 unsigned int i,j,lo,hi;
5273 struct case_node *n;
5277 for (n = nodes; n; n = n->right)
5279 label = label_rtx (n->code_label);
5280 for (i = 0; i < count; i++)
5281 if (same_case_target_p (label, test[i].label))
5286 if (count >= MAX_CASE_BIT_TESTS)
5290 test[i].label = label;
5297 lo = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5298 n->low, minval)), 1);
5299 hi = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5300 n->high, minval)), 1);
5301 for (j = lo; j <= hi; j++)
5302 if (j >= HOST_BITS_PER_WIDE_INT)
5303 test[i].hi |= (HOST_WIDE_INT) 1 << (j - HOST_BITS_PER_INT);
5305 test[i].lo |= (HOST_WIDE_INT) 1 << j;
5308 qsort (test, count, sizeof(*test), case_bit_test_cmp);
5310 index_expr = fold (build (MINUS_EXPR, index_type,
5311 convert (index_type, index_expr),
5312 convert (index_type, minval)));
5313 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5315 index = protect_from_queue (index, 0);
5316 do_pending_stack_adjust ();
5318 mode = TYPE_MODE (index_type);
5319 expr = expand_expr (range, NULL_RTX, VOIDmode, 0);
5320 emit_cmp_and_jump_insns (index, expr, GTU, NULL_RTX, mode, 1,
5323 index = convert_to_mode (word_mode, index, 0);
5324 index = expand_binop (word_mode, ashl_optab, const1_rtx,
5325 index, NULL_RTX, 1, OPTAB_WIDEN);
5327 for (i = 0; i < count; i++)
5329 expr = immed_double_const (test[i].lo, test[i].hi, word_mode);
5330 expr = expand_binop (word_mode, and_optab, index, expr,
5331 NULL_RTX, 1, OPTAB_WIDEN);
5332 emit_cmp_and_jump_insns (expr, const0_rtx, NE, NULL_RTX,
5333 word_mode, 1, test[i].label);
5336 emit_jump (default_label);
5339 /* Terminate a case (Pascal) or switch (C) statement
5340 in which ORIG_INDEX is the expression to be tested.
5341 If ORIG_TYPE is not NULL, it is the original ORIG_INDEX
5342 type as given in the source before any compiler conversions.
5343 Generate the code to test it and jump to the right place. */
5346 expand_end_case_type (tree orig_index, tree orig_type)
5348 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE;
5349 rtx default_label = 0;
5350 struct case_node *n, *m;
5351 unsigned int count, uniq;
5357 rtx before_case, end, lab;
5358 struct nesting *thiscase = case_stack;
5359 tree index_expr, index_type;
5360 bool exit_done = false;
5363 /* Don't crash due to previous errors. */
5364 if (thiscase == NULL)
5367 index_expr = thiscase->data.case_stmt.index_expr;
5368 index_type = TREE_TYPE (index_expr);
5369 unsignedp = TREE_UNSIGNED (index_type);
5370 if (orig_type == NULL)
5371 orig_type = TREE_TYPE (orig_index);
5373 do_pending_stack_adjust ();
5375 /* This might get a spurious warning in the presence of a syntax error;
5376 it could be fixed by moving the call to check_seenlabel after the
5377 check for error_mark_node, and copying the code of check_seenlabel that
5378 deals with case_stack->data.case_stmt.line_number_status /
5379 restore_line_number_status in front of the call to end_cleanup_deferral;
5380 However, this might miss some useful warnings in the presence of
5381 non-syntax errors. */
5384 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5385 if (index_type != error_mark_node)
5387 /* If the switch expression was an enumerated type, check that
5388 exactly all enumeration literals are covered by the cases.
5389 The check is made when -Wswitch was specified and there is no
5390 default case, or when -Wswitch-enum was specified. */
5391 if (((warn_switch && !thiscase->data.case_stmt.default_label)
5392 || warn_switch_enum)
5393 && TREE_CODE (orig_type) == ENUMERAL_TYPE
5394 && TREE_CODE (index_expr) != INTEGER_CST)
5395 check_for_full_enumeration_handling (orig_type);
5397 if (warn_switch_default && !thiscase->data.case_stmt.default_label)
5398 warning ("switch missing default case");
5400 /* If we don't have a default-label, create one here,
5401 after the body of the switch. */
5402 if (thiscase->data.case_stmt.default_label == 0)
5404 thiscase->data.case_stmt.default_label
5405 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5406 /* Share the exit label if possible. */
5407 if (thiscase->exit_label)
5409 SET_DECL_RTL (thiscase->data.case_stmt.default_label,
5410 thiscase->exit_label);
5413 expand_label (thiscase->data.case_stmt.default_label);
5415 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5417 before_case = get_last_insn ();
5419 if (thiscase->data.case_stmt.case_list
5420 && thiscase->data.case_stmt.case_list->left)
5421 thiscase->data.case_stmt.case_list
5422 = case_tree2list (thiscase->data.case_stmt.case_list, 0);
5424 /* Simplify the case-list before we count it. */
5425 group_case_nodes (thiscase->data.case_stmt.case_list);
5426 strip_default_case_nodes (&thiscase->data.case_stmt.case_list,
5429 /* Get upper and lower bounds of case values.
5430 Also convert all the case values to the index expr's data type. */
5434 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5436 /* Check low and high label values are integers. */
5437 if (TREE_CODE (n->low) != INTEGER_CST)
5439 if (TREE_CODE (n->high) != INTEGER_CST)
5442 n->low = convert (index_type, n->low);
5443 n->high = convert (index_type, n->high);
5445 /* Count the elements and track the largest and smallest
5446 of them (treating them as signed even if they are not). */
5454 if (INT_CST_LT (n->low, minval))
5456 if (INT_CST_LT (maxval, n->high))
5459 /* A range counts double, since it requires two compares. */
5460 if (! tree_int_cst_equal (n->low, n->high))
5463 /* Count the number of unique case node targets. */
5465 lab = label_rtx (n->code_label);
5466 for (m = thiscase->data.case_stmt.case_list; m != n; m = m->right)
5467 if (same_case_target_p (label_rtx (m->code_label), lab))
5474 /* Compute span of values. */
5476 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5478 end_cleanup_deferral ();
5482 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5484 emit_jump (default_label);
5487 /* Try implementing this switch statement by a short sequence of
5488 bit-wise comparisons. However, we let the binary-tree case
5489 below handle constant index expressions. */
5490 else if (CASE_USE_BIT_TESTS
5491 && ! TREE_CONSTANT (index_expr)
5492 && compare_tree_int (range, GET_MODE_BITSIZE (word_mode)) < 0
5493 && compare_tree_int (range, 0) > 0
5494 && lshift_cheap_p ()
5495 && ((uniq == 1 && count >= 3)
5496 || (uniq == 2 && count >= 5)
5497 || (uniq == 3 && count >= 6)))
5499 /* Optimize the case where all the case values fit in a
5500 word without having to subtract MINVAL. In this case,
5501 we can optimize away the subtraction. */
5502 if (compare_tree_int (minval, 0) > 0
5503 && compare_tree_int (maxval, GET_MODE_BITSIZE (word_mode)) < 0)
5505 minval = integer_zero_node;
5508 emit_case_bit_tests (index_type, index_expr, minval, range,
5509 thiscase->data.case_stmt.case_list,
5513 /* If range of values is much bigger than number of values,
5514 make a sequence of conditional branches instead of a dispatch.
5515 If the switch-index is a constant, do it this way
5516 because we can optimize it. */
5518 else if (count < case_values_threshold ()
5519 || compare_tree_int (range,
5520 (optimize_size ? 3 : 10) * count) > 0
5521 /* RANGE may be signed, and really large ranges will show up
5522 as negative numbers. */
5523 || compare_tree_int (range, 0) < 0
5524 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5527 || TREE_CONSTANT (index_expr))
5529 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5531 /* If the index is a short or char that we do not have
5532 an insn to handle comparisons directly, convert it to
5533 a full integer now, rather than letting each comparison
5534 generate the conversion. */
5536 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5537 && ! have_insn_for (COMPARE, GET_MODE (index)))
5539 enum machine_mode wider_mode;
5540 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5541 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5542 if (have_insn_for (COMPARE, wider_mode))
5544 index = convert_to_mode (wider_mode, index, unsignedp);
5550 do_pending_stack_adjust ();
5552 index = protect_from_queue (index, 0);
5553 if (GET_CODE (index) == MEM)
5554 index = copy_to_reg (index);
5555 if (GET_CODE (index) == CONST_INT
5556 || TREE_CODE (index_expr) == INTEGER_CST)
5558 /* Make a tree node with the proper constant value
5559 if we don't already have one. */
5560 if (TREE_CODE (index_expr) != INTEGER_CST)
5563 = build_int_2 (INTVAL (index),
5564 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5565 index_expr = convert (index_type, index_expr);
5568 /* For constant index expressions we need only
5569 issue an unconditional branch to the appropriate
5570 target code. The job of removing any unreachable
5571 code is left to the optimization phase if the
5572 "-O" option is specified. */
5573 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5574 if (! tree_int_cst_lt (index_expr, n->low)
5575 && ! tree_int_cst_lt (n->high, index_expr))
5579 emit_jump (label_rtx (n->code_label));
5581 emit_jump (default_label);
5585 /* If the index expression is not constant we generate
5586 a binary decision tree to select the appropriate
5587 target code. This is done as follows:
5589 The list of cases is rearranged into a binary tree,
5590 nearly optimal assuming equal probability for each case.
5592 The tree is transformed into RTL, eliminating
5593 redundant test conditions at the same time.
5595 If program flow could reach the end of the
5596 decision tree an unconditional jump to the
5597 default code is emitted. */
5600 = (TREE_CODE (orig_type) != ENUMERAL_TYPE
5601 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5602 balance_case_nodes (&thiscase->data.case_stmt.case_list, NULL);
5603 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5604 default_label, index_type);
5605 emit_jump_if_reachable (default_label);
5610 table_label = gen_label_rtx ();
5611 if (! try_casesi (index_type, index_expr, minval, range,
5612 table_label, default_label))
5614 index_type = thiscase->data.case_stmt.nominal_type;
5616 /* Index jumptables from zero for suitable values of
5617 minval to avoid a subtraction. */
5619 && compare_tree_int (minval, 0) > 0
5620 && compare_tree_int (minval, 3) < 0)
5622 minval = integer_zero_node;
5626 if (! try_tablejump (index_type, index_expr, minval, range,
5627 table_label, default_label))
5631 /* Get table of labels to jump to, in order of case index. */
5633 ncases = tree_low_cst (range, 0) + 1;
5634 labelvec = alloca (ncases * sizeof (rtx));
5635 memset (labelvec, 0, ncases * sizeof (rtx));
5637 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5639 /* Compute the low and high bounds relative to the minimum
5640 value since that should fit in a HOST_WIDE_INT while the
5641 actual values may not. */
5643 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5644 n->low, minval)), 1);
5645 HOST_WIDE_INT i_high
5646 = tree_low_cst (fold (build (MINUS_EXPR, index_type,
5647 n->high, minval)), 1);
5650 for (i = i_low; i <= i_high; i ++)
5652 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5655 /* Fill in the gaps with the default. */
5656 for (i = 0; i < ncases; i++)
5657 if (labelvec[i] == 0)
5658 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5660 /* Output the table. */
5661 emit_label (table_label);
5663 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5664 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5665 gen_rtx_LABEL_REF (Pmode, table_label),
5666 gen_rtvec_v (ncases, labelvec),
5667 const0_rtx, const0_rtx));
5669 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5670 gen_rtvec_v (ncases, labelvec)));
5672 /* If the case insn drops through the table,
5673 after the table we must jump to the default-label.
5674 Otherwise record no drop-through after the table. */
5675 #ifdef CASE_DROPS_THROUGH
5676 emit_jump (default_label);
5682 before_case = NEXT_INSN (before_case);
5683 end = get_last_insn ();
5684 if (squeeze_notes (&before_case, &end))
5686 reorder_insns (before_case, end,
5687 thiscase->data.case_stmt.start);
5690 end_cleanup_deferral ();
5692 if (thiscase->exit_label && !exit_done)
5693 emit_label (thiscase->exit_label);
5695 POPSTACK (case_stack);
5700 /* Convert the tree NODE into a list linked by the right field, with the left
5701 field zeroed. RIGHT is used for recursion; it is a list to be placed
5702 rightmost in the resulting list. */
5704 static struct case_node *
5705 case_tree2list (struct case_node *node, struct case_node *right)
5707 struct case_node *left;
5710 right = case_tree2list (node->right, right);
5712 node->right = right;
5713 if ((left = node->left))
5716 return case_tree2list (left, node);
5722 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5725 do_jump_if_equal (rtx op1, rtx op2, rtx label, int unsignedp)
5727 if (GET_CODE (op1) == CONST_INT && GET_CODE (op2) == CONST_INT)
5733 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX,
5734 (GET_MODE (op1) == VOIDmode
5735 ? GET_MODE (op2) : GET_MODE (op1)),
5739 /* Not all case values are encountered equally. This function
5740 uses a heuristic to weight case labels, in cases where that
5741 looks like a reasonable thing to do.
5743 Right now, all we try to guess is text, and we establish the
5746 chars above space: 16
5755 If we find any cases in the switch that are not either -1 or in the range
5756 of valid ASCII characters, or are control characters other than those
5757 commonly used with "\", don't treat this switch scanning text.
5759 Return 1 if these nodes are suitable for cost estimation, otherwise
5763 estimate_case_costs (case_node_ptr node)
5765 tree min_ascii = integer_minus_one_node;
5766 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5770 /* If we haven't already made the cost table, make it now. Note that the
5771 lower bound of the table is -1, not zero. */
5773 if (! cost_table_initialized)
5775 cost_table_initialized = 1;
5777 for (i = 0; i < 128; i++)
5780 COST_TABLE (i) = 16;
5781 else if (ISPUNCT (i))
5783 else if (ISCNTRL (i))
5784 COST_TABLE (i) = -1;
5787 COST_TABLE (' ') = 8;
5788 COST_TABLE ('\t') = 4;
5789 COST_TABLE ('\0') = 4;
5790 COST_TABLE ('\n') = 2;
5791 COST_TABLE ('\f') = 1;
5792 COST_TABLE ('\v') = 1;
5793 COST_TABLE ('\b') = 1;
5796 /* See if all the case expressions look like text. It is text if the
5797 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5798 as signed arithmetic since we don't want to ever access cost_table with a
5799 value less than -1. Also check that none of the constants in a range
5800 are strange control characters. */
5802 for (n = node; n; n = n->right)
5804 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5807 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5808 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5809 if (COST_TABLE (i) < 0)
5813 /* All interesting values are within the range of interesting
5814 ASCII characters. */
5818 /* Determine whether two case labels branch to the same target. */
5821 same_case_target_p (rtx l1, rtx l2)
5828 i1 = next_real_insn (l1);
5829 i2 = next_real_insn (l2);
5833 if (i1 && simplejump_p (i1))
5835 l1 = XEXP (SET_SRC (PATTERN (i1)), 0);
5838 if (i2 && simplejump_p (i2))
5840 l2 = XEXP (SET_SRC (PATTERN (i2)), 0);
5845 /* Delete nodes that branch to the default label from a list of
5846 case nodes. Eg. case 5: default: becomes just default: */
5849 strip_default_case_nodes (case_node_ptr *prev, rtx deflab)
5856 if (same_case_target_p (label_rtx (ptr->code_label), deflab))
5863 /* Scan an ordered list of case nodes
5864 combining those with consecutive values or ranges.
5866 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5869 group_case_nodes (case_node_ptr head)
5871 case_node_ptr node = head;
5875 rtx lab = label_rtx (node->code_label);
5876 case_node_ptr np = node;
5878 /* Try to group the successors of NODE with NODE. */
5879 while (((np = np->right) != 0)
5880 /* Do they jump to the same place? */
5881 && same_case_target_p (label_rtx (np->code_label), lab)
5882 /* Are their ranges consecutive? */
5883 && tree_int_cst_equal (np->low,
5884 fold (build (PLUS_EXPR,
5885 TREE_TYPE (node->high),
5888 /* An overflow is not consecutive. */
5889 && tree_int_cst_lt (node->high,
5890 fold (build (PLUS_EXPR,
5891 TREE_TYPE (node->high),
5893 integer_one_node))))
5895 node->high = np->high;
5897 /* NP is the first node after NODE which can't be grouped with it.
5898 Delete the nodes in between, and move on to that node. */
5904 /* Take an ordered list of case nodes
5905 and transform them into a near optimal binary tree,
5906 on the assumption that any target code selection value is as
5907 likely as any other.
5909 The transformation is performed by splitting the ordered
5910 list into two equal sections plus a pivot. The parts are
5911 then attached to the pivot as left and right branches. Each
5912 branch is then transformed recursively. */
5915 balance_case_nodes (case_node_ptr *head, case_node_ptr parent)
5928 /* Count the number of entries on branch. Also count the ranges. */
5932 if (!tree_int_cst_equal (np->low, np->high))
5936 cost += COST_TABLE (TREE_INT_CST_LOW (np->high));
5940 cost += COST_TABLE (TREE_INT_CST_LOW (np->low));
5948 /* Split this list if it is long enough for that to help. */
5953 /* Find the place in the list that bisects the list's total cost,
5954 Here I gets half the total cost. */
5959 /* Skip nodes while their cost does not reach that amount. */
5960 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5961 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->high));
5962 i -= COST_TABLE (TREE_INT_CST_LOW ((*npp)->low));
5965 npp = &(*npp)->right;
5970 /* Leave this branch lopsided, but optimize left-hand
5971 side and fill in `parent' fields for right-hand side. */
5973 np->parent = parent;
5974 balance_case_nodes (&np->left, np);
5975 for (; np->right; np = np->right)
5976 np->right->parent = np;
5980 /* If there are just three nodes, split at the middle one. */
5982 npp = &(*npp)->right;
5985 /* Find the place in the list that bisects the list's total cost,
5986 where ranges count as 2.
5987 Here I gets half the total cost. */
5988 i = (i + ranges + 1) / 2;
5991 /* Skip nodes while their cost does not reach that amount. */
5992 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5997 npp = &(*npp)->right;
6002 np->parent = parent;
6005 /* Optimize each of the two split parts. */
6006 balance_case_nodes (&np->left, np);
6007 balance_case_nodes (&np->right, np);
6011 /* Else leave this branch as one level,
6012 but fill in `parent' fields. */
6014 np->parent = parent;
6015 for (; np->right; np = np->right)
6016 np->right->parent = np;
6021 /* Search the parent sections of the case node tree
6022 to see if a test for the lower bound of NODE would be redundant.
6023 INDEX_TYPE is the type of the index expression.
6025 The instructions to generate the case decision tree are
6026 output in the same order as nodes are processed so it is
6027 known that if a parent node checks the range of the current
6028 node minus one that the current node is bounded at its lower
6029 span. Thus the test would be redundant. */
6032 node_has_low_bound (case_node_ptr node, tree index_type)
6035 case_node_ptr pnode;
6037 /* If the lower bound of this node is the lowest value in the index type,
6038 we need not test it. */
6040 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
6043 /* If this node has a left branch, the value at the left must be less
6044 than that at this node, so it cannot be bounded at the bottom and
6045 we need not bother testing any further. */
6050 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
6051 node->low, integer_one_node));
6053 /* If the subtraction above overflowed, we can't verify anything.
6054 Otherwise, look for a parent that tests our value - 1. */
6056 if (! tree_int_cst_lt (low_minus_one, node->low))
6059 for (pnode = node->parent; pnode; pnode = pnode->parent)
6060 if (tree_int_cst_equal (low_minus_one, pnode->high))
6066 /* Search the parent sections of the case node tree
6067 to see if a test for the upper bound of NODE would be redundant.
6068 INDEX_TYPE is the type of the index expression.
6070 The instructions to generate the case decision tree are
6071 output in the same order as nodes are processed so it is
6072 known that if a parent node checks the range of the current
6073 node plus one that the current node is bounded at its upper
6074 span. Thus the test would be redundant. */
6077 node_has_high_bound (case_node_ptr node, tree index_type)
6080 case_node_ptr pnode;
6082 /* If there is no upper bound, obviously no test is needed. */
6084 if (TYPE_MAX_VALUE (index_type) == NULL)
6087 /* If the upper bound of this node is the highest value in the type
6088 of the index expression, we need not test against it. */
6090 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
6093 /* If this node has a right branch, the value at the right must be greater
6094 than that at this node, so it cannot be bounded at the top and
6095 we need not bother testing any further. */
6100 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6101 node->high, integer_one_node));
6103 /* If the addition above overflowed, we can't verify anything.
6104 Otherwise, look for a parent that tests our value + 1. */
6106 if (! tree_int_cst_lt (node->high, high_plus_one))
6109 for (pnode = node->parent; pnode; pnode = pnode->parent)
6110 if (tree_int_cst_equal (high_plus_one, pnode->low))
6116 /* Search the parent sections of the
6117 case node tree to see if both tests for the upper and lower
6118 bounds of NODE would be redundant. */
6121 node_is_bounded (case_node_ptr node, tree index_type)
6123 return (node_has_low_bound (node, index_type)
6124 && node_has_high_bound (node, index_type));
6127 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6130 emit_jump_if_reachable (rtx label)
6132 if (GET_CODE (get_last_insn ()) != BARRIER)
6136 /* Emit step-by-step code to select a case for the value of INDEX.
6137 The thus generated decision tree follows the form of the
6138 case-node binary tree NODE, whose nodes represent test conditions.
6139 INDEX_TYPE is the type of the index of the switch.
6141 Care is taken to prune redundant tests from the decision tree
6142 by detecting any boundary conditions already checked by
6143 emitted rtx. (See node_has_high_bound, node_has_low_bound
6144 and node_is_bounded, above.)
6146 Where the test conditions can be shown to be redundant we emit
6147 an unconditional jump to the target code. As a further
6148 optimization, the subordinates of a tree node are examined to
6149 check for bounded nodes. In this case conditional and/or
6150 unconditional jumps as a result of the boundary check for the
6151 current node are arranged to target the subordinates associated
6152 code for out of bound conditions on the current node.
6154 We can assume that when control reaches the code generated here,
6155 the index value has already been compared with the parents
6156 of this node, and determined to be on the same side of each parent
6157 as this node is. Thus, if this node tests for the value 51,
6158 and a parent tested for 52, we don't need to consider
6159 the possibility of a value greater than 51. If another parent
6160 tests for the value 50, then this node need not test anything. */
6163 emit_case_nodes (rtx index, case_node_ptr node, rtx default_label,
6166 /* If INDEX has an unsigned type, we must make unsigned branches. */
6167 int unsignedp = TREE_UNSIGNED (index_type);
6168 enum machine_mode mode = GET_MODE (index);
6169 enum machine_mode imode = TYPE_MODE (index_type);
6171 /* See if our parents have already tested everything for us.
6172 If they have, emit an unconditional jump for this node. */
6173 if (node_is_bounded (node, index_type))
6174 emit_jump (label_rtx (node->code_label));
6176 else if (tree_int_cst_equal (node->low, node->high))
6178 /* Node is single valued. First see if the index expression matches
6179 this node and then check our children, if any. */
6181 do_jump_if_equal (index,
6182 convert_modes (mode, imode,
6183 expand_expr (node->low, NULL_RTX,
6186 label_rtx (node->code_label), unsignedp);
6188 if (node->right != 0 && node->left != 0)
6190 /* This node has children on both sides.
6191 Dispatch to one side or the other
6192 by comparing the index value with this node's value.
6193 If one subtree is bounded, check that one first,
6194 so we can avoid real branches in the tree. */
6196 if (node_is_bounded (node->right, index_type))
6198 emit_cmp_and_jump_insns (index,
6201 expand_expr (node->high, NULL_RTX,
6204 GT, NULL_RTX, mode, unsignedp,
6205 label_rtx (node->right->code_label));
6206 emit_case_nodes (index, node->left, default_label, index_type);
6209 else if (node_is_bounded (node->left, index_type))
6211 emit_cmp_and_jump_insns (index,
6214 expand_expr (node->high, NULL_RTX,
6217 LT, NULL_RTX, mode, unsignedp,
6218 label_rtx (node->left->code_label));
6219 emit_case_nodes (index, node->right, default_label, index_type);
6224 /* Neither node is bounded. First distinguish the two sides;
6225 then emit the code for one side at a time. */
6227 tree test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6229 /* See if the value is on the right. */
6230 emit_cmp_and_jump_insns (index,
6233 expand_expr (node->high, NULL_RTX,
6236 GT, NULL_RTX, mode, unsignedp,
6237 label_rtx (test_label));
6239 /* Value must be on the left.
6240 Handle the left-hand subtree. */
6241 emit_case_nodes (index, node->left, default_label, index_type);
6242 /* If left-hand subtree does nothing,
6244 emit_jump_if_reachable (default_label);
6246 /* Code branches here for the right-hand subtree. */
6247 expand_label (test_label);
6248 emit_case_nodes (index, node->right, default_label, index_type);
6252 else if (node->right != 0 && node->left == 0)
6254 /* Here we have a right child but no left so we issue conditional
6255 branch to default and process the right child.
6257 Omit the conditional branch to default if we it avoid only one
6258 right child; it costs too much space to save so little time. */
6260 if (node->right->right || node->right->left
6261 || !tree_int_cst_equal (node->right->low, node->right->high))
6263 if (!node_has_low_bound (node, index_type))
6265 emit_cmp_and_jump_insns (index,
6268 expand_expr (node->high, NULL_RTX,
6271 LT, NULL_RTX, mode, unsignedp,
6275 emit_case_nodes (index, node->right, default_label, index_type);
6278 /* We cannot process node->right normally
6279 since we haven't ruled out the numbers less than
6280 this node's value. So handle node->right explicitly. */
6281 do_jump_if_equal (index,
6284 expand_expr (node->right->low, NULL_RTX,
6287 label_rtx (node->right->code_label), unsignedp);
6290 else if (node->right == 0 && node->left != 0)
6292 /* Just one subtree, on the left. */
6293 if (node->left->left || node->left->right
6294 || !tree_int_cst_equal (node->left->low, node->left->high))
6296 if (!node_has_high_bound (node, index_type))
6298 emit_cmp_and_jump_insns (index,
6301 expand_expr (node->high, NULL_RTX,
6304 GT, NULL_RTX, mode, unsignedp,
6308 emit_case_nodes (index, node->left, default_label, index_type);
6311 /* We cannot process node->left normally
6312 since we haven't ruled out the numbers less than
6313 this node's value. So handle node->left explicitly. */
6314 do_jump_if_equal (index,
6317 expand_expr (node->left->low, NULL_RTX,
6320 label_rtx (node->left->code_label), unsignedp);
6325 /* Node is a range. These cases are very similar to those for a single
6326 value, except that we do not start by testing whether this node
6327 is the one to branch to. */
6329 if (node->right != 0 && node->left != 0)
6331 /* Node has subtrees on both sides.
6332 If the right-hand subtree is bounded,
6333 test for it first, since we can go straight there.
6334 Otherwise, we need to make a branch in the control structure,
6335 then handle the two subtrees. */
6336 tree test_label = 0;
6338 if (node_is_bounded (node->right, index_type))
6339 /* Right hand node is fully bounded so we can eliminate any
6340 testing and branch directly to the target code. */
6341 emit_cmp_and_jump_insns (index,
6344 expand_expr (node->high, NULL_RTX,
6347 GT, NULL_RTX, mode, unsignedp,
6348 label_rtx (node->right->code_label));
6351 /* Right hand node requires testing.
6352 Branch to a label where we will handle it later. */
6354 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6355 emit_cmp_and_jump_insns (index,
6358 expand_expr (node->high, NULL_RTX,
6361 GT, NULL_RTX, mode, unsignedp,
6362 label_rtx (test_label));
6365 /* Value belongs to this node or to the left-hand subtree. */
6367 emit_cmp_and_jump_insns (index,
6370 expand_expr (node->low, NULL_RTX,
6373 GE, NULL_RTX, mode, unsignedp,
6374 label_rtx (node->code_label));
6376 /* Handle the left-hand subtree. */
6377 emit_case_nodes (index, node->left, default_label, index_type);
6379 /* If right node had to be handled later, do that now. */
6383 /* If the left-hand subtree fell through,
6384 don't let it fall into the right-hand subtree. */
6385 emit_jump_if_reachable (default_label);
6387 expand_label (test_label);
6388 emit_case_nodes (index, node->right, default_label, index_type);
6392 else if (node->right != 0 && node->left == 0)
6394 /* Deal with values to the left of this node,
6395 if they are possible. */
6396 if (!node_has_low_bound (node, index_type))
6398 emit_cmp_and_jump_insns (index,
6401 expand_expr (node->low, NULL_RTX,
6404 LT, NULL_RTX, mode, unsignedp,
6408 /* Value belongs to this node or to the right-hand subtree. */
6410 emit_cmp_and_jump_insns (index,
6413 expand_expr (node->high, NULL_RTX,
6416 LE, NULL_RTX, mode, unsignedp,
6417 label_rtx (node->code_label));
6419 emit_case_nodes (index, node->right, default_label, index_type);
6422 else if (node->right == 0 && node->left != 0)
6424 /* Deal with values to the right of this node,
6425 if they are possible. */
6426 if (!node_has_high_bound (node, index_type))
6428 emit_cmp_and_jump_insns (index,
6431 expand_expr (node->high, NULL_RTX,
6434 GT, NULL_RTX, mode, unsignedp,
6438 /* Value belongs to this node or to the left-hand subtree. */
6440 emit_cmp_and_jump_insns (index,
6443 expand_expr (node->low, NULL_RTX,
6446 GE, NULL_RTX, mode, unsignedp,
6447 label_rtx (node->code_label));
6449 emit_case_nodes (index, node->left, default_label, index_type);
6454 /* Node has no children so we check low and high bounds to remove
6455 redundant tests. Only one of the bounds can exist,
6456 since otherwise this node is bounded--a case tested already. */
6457 int high_bound = node_has_high_bound (node, index_type);
6458 int low_bound = node_has_low_bound (node, index_type);
6460 if (!high_bound && low_bound)
6462 emit_cmp_and_jump_insns (index,
6465 expand_expr (node->high, NULL_RTX,
6468 GT, NULL_RTX, mode, unsignedp,
6472 else if (!low_bound && high_bound)
6474 emit_cmp_and_jump_insns (index,
6477 expand_expr (node->low, NULL_RTX,
6480 LT, NULL_RTX, mode, unsignedp,
6483 else if (!low_bound && !high_bound)
6485 /* Widen LOW and HIGH to the same width as INDEX. */
6486 tree type = (*lang_hooks.types.type_for_mode) (mode, unsignedp);
6487 tree low = build1 (CONVERT_EXPR, type, node->low);
6488 tree high = build1 (CONVERT_EXPR, type, node->high);
6489 rtx low_rtx, new_index, new_bound;
6491 /* Instead of doing two branches, emit one unsigned branch for
6492 (index-low) > (high-low). */
6493 low_rtx = expand_expr (low, NULL_RTX, mode, 0);
6494 new_index = expand_simple_binop (mode, MINUS, index, low_rtx,
6495 NULL_RTX, unsignedp,
6497 new_bound = expand_expr (fold (build (MINUS_EXPR, type,
6501 emit_cmp_and_jump_insns (new_index, new_bound, GT, NULL_RTX,
6502 mode, 1, default_label);
6505 emit_jump (label_rtx (node->code_label));
6510 #include "gt-stmt.h"