1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 88, 89, 92, 93, 94, 1995 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 /* This file handles the generation of rtl code from tree structure
22 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
23 It also creates the rtl expressions for parameters and auto variables
24 and has full responsibility for allocating stack slots.
26 The functions whose names start with `expand_' are called by the
27 parser to generate RTL instructions for various kinds of constructs.
29 Some control and binding constructs require calling several such
30 functions at different times. For example, a simple if-then
31 is expanded by calling `expand_start_cond' (with the condition-expression
32 as argument) before parsing the then-clause and calling `expand_end_cond'
33 after parsing the then-clause. */
44 #include "insn-flags.h"
45 #include "insn-config.h"
46 #include "insn-codes.h"
48 #include "hard-reg-set.h"
55 #include "bc-typecd.h"
56 #include "bc-opcode.h"
60 #define obstack_chunk_alloc xmalloc
61 #define obstack_chunk_free free
62 struct obstack stmt_obstack;
64 /* Filename and line number of last line-number note,
65 whether we actually emitted it or not. */
69 /* Nonzero if within a ({...}) grouping, in which case we must
70 always compute a value for each expr-stmt in case it is the last one. */
72 int expr_stmts_for_value;
74 /* Each time we expand an expression-statement,
75 record the expr's type and its RTL value here. */
77 static tree last_expr_type;
78 static rtx last_expr_value;
80 /* Each time we expand the end of a binding contour (in `expand_end_bindings')
81 and we emit a new NOTE_INSN_BLOCK_END note, we save a pointer to it here.
82 This is used by the `remember_end_note' function to record the endpoint
83 of each generated block in its associated BLOCK node. */
85 static rtx last_block_end_note;
87 /* Number of binding contours started so far in this function. */
89 int block_start_count;
91 /* Nonzero if function being compiled needs to
92 return the address of where it has put a structure value. */
94 extern int current_function_returns_pcc_struct;
96 /* Label that will go on parm cleanup code, if any.
97 Jumping to this label runs cleanup code for parameters, if
98 such code must be run. Following this code is the logical return label. */
100 extern rtx cleanup_label;
102 /* Label that will go on function epilogue.
103 Jumping to this label serves as a "return" instruction
104 on machines which require execution of the epilogue on all returns. */
106 extern rtx return_label;
108 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
109 So we can mark them all live at the end of the function, if nonopt. */
110 extern rtx save_expr_regs;
112 /* Offset to end of allocated area of stack frame.
113 If stack grows down, this is the address of the last stack slot allocated.
114 If stack grows up, this is the address for the next slot. */
115 extern int frame_offset;
117 /* Label to jump back to for tail recursion, or 0 if we have
118 not yet needed one for this function. */
119 extern rtx tail_recursion_label;
121 /* Place after which to insert the tail_recursion_label if we need one. */
122 extern rtx tail_recursion_reentry;
124 /* Location at which to save the argument pointer if it will need to be
125 referenced. There are two cases where this is done: if nonlocal gotos
126 exist, or if vars whose is an offset from the argument pointer will be
127 needed by inner routines. */
129 extern rtx arg_pointer_save_area;
131 /* Chain of all RTL_EXPRs that have insns in them. */
132 extern tree rtl_expr_chain;
134 #if 0 /* Turned off because 0 seems to work just as well. */
135 /* Cleanup lists are required for binding levels regardless of whether
136 that binding level has cleanups or not. This node serves as the
137 cleanup list whenever an empty list is required. */
138 static tree empty_cleanup_list;
141 extern void (*interim_eh_hook) PROTO((tree));
143 /* Functions and data structures for expanding case statements. */
145 /* Case label structure, used to hold info on labels within case
146 statements. We handle "range" labels; for a single-value label
147 as in C, the high and low limits are the same.
149 A chain of case nodes is initially maintained via the RIGHT fields
150 in the nodes. Nodes with higher case values are later in the list.
152 Switch statements can be output in one of two forms. A branch table
153 is used if there are more than a few labels and the labels are dense
154 within the range between the smallest and largest case value. If a
155 branch table is used, no further manipulations are done with the case
158 The alternative to the use of a branch table is to generate a series
159 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
160 and PARENT fields to hold a binary tree. Initially the tree is
161 totally unbalanced, with everything on the right. We balance the tree
162 with nodes on the left having lower case values than the parent
163 and nodes on the right having higher values. We then output the tree
168 struct case_node *left; /* Left son in binary tree */
169 struct case_node *right; /* Right son in binary tree; also node chain */
170 struct case_node *parent; /* Parent of node in binary tree */
171 tree low; /* Lowest index value for this label */
172 tree high; /* Highest index value for this label */
173 tree code_label; /* Label to jump to when node matches */
176 typedef struct case_node case_node;
177 typedef struct case_node *case_node_ptr;
179 /* These are used by estimate_case_costs and balance_case_nodes. */
181 /* This must be a signed type, and non-ANSI compilers lack signed char. */
182 static short *cost_table;
183 static int use_cost_table;
185 /* Stack of control and binding constructs we are currently inside.
187 These constructs begin when you call `expand_start_WHATEVER'
188 and end when you call `expand_end_WHATEVER'. This stack records
189 info about how the construct began that tells the end-function
190 what to do. It also may provide information about the construct
191 to alter the behavior of other constructs within the body.
192 For example, they may affect the behavior of C `break' and `continue'.
194 Each construct gets one `struct nesting' object.
195 All of these objects are chained through the `all' field.
196 `nesting_stack' points to the first object (innermost construct).
197 The position of an entry on `nesting_stack' is in its `depth' field.
199 Each type of construct has its own individual stack.
200 For example, loops have `loop_stack'. Each object points to the
201 next object of the same type through the `next' field.
203 Some constructs are visible to `break' exit-statements and others
204 are not. Which constructs are visible depends on the language.
205 Therefore, the data structure allows each construct to be visible
206 or not, according to the args given when the construct is started.
207 The construct is visible if the `exit_label' field is non-null.
208 In that case, the value should be a CODE_LABEL rtx. */
213 struct nesting *next;
218 /* For conds (if-then and if-then-else statements). */
221 /* Label for the end of the if construct.
222 There is none if EXITFLAG was not set
223 and no `else' has been seen yet. */
225 /* Label for the end of this alternative.
226 This may be the end of the if or the next else/elseif. */
232 /* Label at the top of the loop; place to loop back to. */
234 /* Label at the end of the whole construct. */
236 /* Label before a jump that branches to the end of the whole
237 construct. This is where destructors go if any. */
239 /* Label for `continue' statement to jump to;
240 this is in front of the stepper of the loop. */
243 /* For variable binding contours. */
246 /* Sequence number of this binding contour within the function,
247 in order of entry. */
248 int block_start_count;
249 /* Nonzero => value to restore stack to on exit. Complemented by
250 bc_stack_level (see below) when generating bytecodes. */
252 /* The NOTE that starts this contour.
253 Used by expand_goto to check whether the destination
254 is within each contour or not. */
256 /* Innermost containing binding contour that has a stack level. */
257 struct nesting *innermost_stack_block;
258 /* List of cleanups to be run on exit from this contour.
259 This is a list of expressions to be evaluated.
260 The TREE_PURPOSE of each link is the ..._DECL node
261 which the cleanup pertains to. */
263 /* List of cleanup-lists of blocks containing this block,
264 as they were at the locus where this block appears.
265 There is an element for each containing block,
266 ordered innermost containing block first.
267 The tail of this list can be 0 (was empty_cleanup_list),
268 if all remaining elements would be empty lists.
269 The element's TREE_VALUE is the cleanup-list of that block,
270 which may be null. */
272 /* Chain of labels defined inside this binding contour.
273 For contours that have stack levels or cleanups. */
274 struct label_chain *label_chain;
275 /* Number of function calls seen, as of start of this block. */
276 int function_call_count;
277 /* Bytecode specific: stack level to restore stack to on exit. */
280 /* For switch (C) or case (Pascal) statements,
281 and also for dummies (see `expand_start_case_dummy'). */
284 /* The insn after which the case dispatch should finally
285 be emitted. Zero for a dummy. */
287 /* For bytecodes, the case table is in-lined right in the code.
288 A label is needed for skipping over this block. It is only
289 used when generating bytecodes. */
291 /* A list of case labels, kept in ascending order by value
292 as the list is built.
293 During expand_end_case, this list may be rearranged into a
294 nearly balanced binary tree. */
295 struct case_node *case_list;
296 /* Label to jump to if no case matches. */
298 /* The expression to be dispatched on. */
300 /* Type that INDEX_EXPR should be converted to. */
302 /* Number of range exprs in case statement. */
304 /* Name of this kind of statement, for warnings. */
306 /* Nonzero if a case label has been seen in this case stmt. */
312 /* Chain of all pending binding contours. */
313 struct nesting *block_stack;
315 /* If any new stacks are added here, add them to POPSTACKS too. */
317 /* Chain of all pending binding contours that restore stack levels
319 struct nesting *stack_block_stack;
321 /* Chain of all pending conditional statements. */
322 struct nesting *cond_stack;
324 /* Chain of all pending loops. */
325 struct nesting *loop_stack;
327 /* Chain of all pending case or switch statements. */
328 struct nesting *case_stack;
330 /* Separate chain including all of the above,
331 chained through the `all' field. */
332 struct nesting *nesting_stack;
334 /* Number of entries on nesting_stack now. */
337 /* Allocate and return a new `struct nesting'. */
339 #define ALLOC_NESTING() \
340 (struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
342 /* Pop the nesting stack element by element until we pop off
343 the element which is at the top of STACK.
344 Update all the other stacks, popping off elements from them
345 as we pop them from nesting_stack. */
347 #define POPSTACK(STACK) \
348 do { struct nesting *target = STACK; \
349 struct nesting *this; \
350 do { this = nesting_stack; \
351 if (loop_stack == this) \
352 loop_stack = loop_stack->next; \
353 if (cond_stack == this) \
354 cond_stack = cond_stack->next; \
355 if (block_stack == this) \
356 block_stack = block_stack->next; \
357 if (stack_block_stack == this) \
358 stack_block_stack = stack_block_stack->next; \
359 if (case_stack == this) \
360 case_stack = case_stack->next; \
361 nesting_depth = nesting_stack->depth - 1; \
362 nesting_stack = this->all; \
363 obstack_free (&stmt_obstack, this); } \
364 while (this != target); } while (0)
366 /* In some cases it is impossible to generate code for a forward goto
367 until the label definition is seen. This happens when it may be necessary
368 for the goto to reset the stack pointer: we don't yet know how to do that.
369 So expand_goto puts an entry on this fixup list.
370 Each time a binding contour that resets the stack is exited,
372 If the target label has now been defined, we can insert the proper code. */
376 /* Points to following fixup. */
377 struct goto_fixup *next;
378 /* Points to the insn before the jump insn.
379 If more code must be inserted, it goes after this insn. */
381 /* The LABEL_DECL that this jump is jumping to, or 0
382 for break, continue or return. */
384 /* The BLOCK for the place where this goto was found. */
386 /* The CODE_LABEL rtx that this is jumping to. */
388 /* Number of binding contours started in current function
389 before the label reference. */
390 int block_start_count;
391 /* The outermost stack level that should be restored for this jump.
392 Each time a binding contour that resets the stack is exited,
393 if the target label is *not* yet defined, this slot is updated. */
395 /* List of lists of cleanup expressions to be run by this goto.
396 There is one element for each block that this goto is within.
397 The tail of this list can be 0 (was empty_cleanup_list),
398 if all remaining elements would be empty.
399 The TREE_VALUE contains the cleanup list of that block as of the
400 time this goto was seen.
401 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
402 tree cleanup_list_list;
404 /* Bytecode specific members follow */
406 /* The label that this jump is jumping to, or 0 for break, continue
408 struct bc_label *bc_target;
410 /* The label we use for the fixup patch */
411 struct bc_label *label;
413 /* True (non-0) if fixup has been handled */
416 /* Like stack_level above, except refers to the interpreter stack */
420 static struct goto_fixup *goto_fixup_chain;
422 /* Within any binding contour that must restore a stack level,
423 all labels are recorded with a chain of these structures. */
427 /* Points to following fixup. */
428 struct label_chain *next;
431 static void expand_goto_internal PROTO((tree, rtx, rtx));
432 static void bc_expand_goto_internal PROTO((enum bytecode_opcode,
433 struct bc_label *, tree));
434 static int expand_fixup PROTO((tree, rtx, rtx));
435 static void bc_expand_fixup PROTO((enum bytecode_opcode,
436 struct bc_label *, int));
437 static void fixup_gotos PROTO((struct nesting *, rtx, tree,
439 static void bc_fixup_gotos PROTO((struct nesting *, int, tree,
441 static int warn_if_unused_value PROTO((tree));
442 static void bc_expand_start_cond PROTO((tree, int));
443 static void bc_expand_end_cond PROTO((void));
444 static void bc_expand_start_else PROTO((void));
445 static void bc_expand_end_loop PROTO((void));
446 static void bc_expand_end_bindings PROTO((tree, int, int));
447 static void bc_expand_decl PROTO((tree, tree));
448 static void bc_expand_variable_local_init PROTO((tree));
449 static void bc_expand_decl_init PROTO((tree));
450 static void expand_null_return_1 PROTO((rtx, int));
451 static void expand_value_return PROTO((rtx));
452 static int tail_recursion_args PROTO((tree, tree));
453 static void expand_cleanups PROTO((tree, tree, int, int));
454 static void bc_expand_start_case PROTO((struct nesting *, tree,
456 static int bc_pushcase PROTO((tree, tree));
457 static void bc_check_for_full_enumeration_handling PROTO((tree));
458 static void bc_expand_end_case PROTO((tree));
459 static void do_jump_if_equal PROTO((rtx, rtx, rtx, int));
460 static int estimate_case_costs PROTO((case_node_ptr));
461 static void group_case_nodes PROTO((case_node_ptr));
462 static void balance_case_nodes PROTO((case_node_ptr *,
464 static int node_has_low_bound PROTO((case_node_ptr, tree));
465 static int node_has_high_bound PROTO((case_node_ptr, tree));
466 static int node_is_bounded PROTO((case_node_ptr, tree));
467 static void emit_jump_if_reachable PROTO((rtx));
468 static void emit_case_nodes PROTO((rtx, case_node_ptr, rtx, tree));
470 int bc_expand_exit_loop_if_false ();
471 void bc_expand_start_cond ();
472 void bc_expand_end_cond ();
473 void bc_expand_start_else ();
474 void bc_expand_end_bindings ();
475 void bc_expand_start_case ();
476 void bc_check_for_full_enumeration_handling ();
477 void bc_expand_end_case ();
478 void bc_expand_decl ();
480 extern rtx bc_allocate_local ();
481 extern rtx bc_allocate_variable_array ();
486 gcc_obstack_init (&stmt_obstack);
488 empty_cleanup_list = build_tree_list (NULL_TREE, NULL_TREE);
493 init_stmt_for_function ()
495 /* We are not currently within any block, conditional, loop or case. */
497 stack_block_stack = 0;
504 block_start_count = 0;
506 /* No gotos have been expanded yet. */
507 goto_fixup_chain = 0;
509 /* We are not processing a ({...}) grouping. */
510 expr_stmts_for_value = 0;
518 p->block_stack = block_stack;
519 p->stack_block_stack = stack_block_stack;
520 p->cond_stack = cond_stack;
521 p->loop_stack = loop_stack;
522 p->case_stack = case_stack;
523 p->nesting_stack = nesting_stack;
524 p->nesting_depth = nesting_depth;
525 p->block_start_count = block_start_count;
526 p->last_expr_type = last_expr_type;
527 p->last_expr_value = last_expr_value;
528 p->expr_stmts_for_value = expr_stmts_for_value;
529 p->emit_filename = emit_filename;
530 p->emit_lineno = emit_lineno;
531 p->goto_fixup_chain = goto_fixup_chain;
535 restore_stmt_status (p)
538 block_stack = p->block_stack;
539 stack_block_stack = p->stack_block_stack;
540 cond_stack = p->cond_stack;
541 loop_stack = p->loop_stack;
542 case_stack = p->case_stack;
543 nesting_stack = p->nesting_stack;
544 nesting_depth = p->nesting_depth;
545 block_start_count = p->block_start_count;
546 last_expr_type = p->last_expr_type;
547 last_expr_value = p->last_expr_value;
548 expr_stmts_for_value = p->expr_stmts_for_value;
549 emit_filename = p->emit_filename;
550 emit_lineno = p->emit_lineno;
551 goto_fixup_chain = p->goto_fixup_chain;
554 /* Emit a no-op instruction. */
561 if (!output_bytecode)
563 last_insn = get_last_insn ();
565 && (GET_CODE (last_insn) == CODE_LABEL
566 || prev_real_insn (last_insn) == 0))
567 emit_insn (gen_nop ());
571 /* Return the rtx-label that corresponds to a LABEL_DECL,
572 creating it if necessary. */
578 if (TREE_CODE (label) != LABEL_DECL)
581 if (DECL_RTL (label))
582 return DECL_RTL (label);
584 return DECL_RTL (label) = gen_label_rtx ();
587 /* Add an unconditional jump to LABEL as the next sequential instruction. */
593 do_pending_stack_adjust ();
594 emit_jump_insn (gen_jump (label));
598 /* Emit code to jump to the address
599 specified by the pointer expression EXP. */
602 expand_computed_goto (exp)
607 bc_expand_expr (exp);
608 bc_emit_instruction (jumpP);
612 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
614 emit_indirect_jump (x);
618 /* Handle goto statements and the labels that they can go to. */
620 /* Specify the location in the RTL code of a label LABEL,
621 which is a LABEL_DECL tree node.
623 This is used for the kind of label that the user can jump to with a
624 goto statement, and for alternatives of a switch or case statement.
625 RTL labels generated for loops and conditionals don't go through here;
626 they are generated directly at the RTL level, by other functions below.
628 Note that this has nothing to do with defining label *names*.
629 Languages vary in how they do that and what that even means. */
635 struct label_chain *p;
639 if (! DECL_RTL (label))
640 DECL_RTL (label) = bc_gen_rtx ((char *) 0, 0, bc_get_bytecode_label ());
641 if (! bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (DECL_RTL (label))))
642 error ("multiply defined label");
646 do_pending_stack_adjust ();
647 emit_label (label_rtx (label));
648 if (DECL_NAME (label))
649 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
651 if (stack_block_stack != 0)
653 p = (struct label_chain *) oballoc (sizeof (struct label_chain));
654 p->next = stack_block_stack->data.block.label_chain;
655 stack_block_stack->data.block.label_chain = p;
660 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
661 from nested functions. */
664 declare_nonlocal_label (label)
667 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
668 LABEL_PRESERVE_P (label_rtx (label)) = 1;
669 if (nonlocal_goto_handler_slot == 0)
671 nonlocal_goto_handler_slot
672 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
673 emit_stack_save (SAVE_NONLOCAL,
674 &nonlocal_goto_stack_level,
675 PREV_INSN (tail_recursion_reentry));
679 /* Generate RTL code for a `goto' statement with target label LABEL.
680 LABEL should be a LABEL_DECL tree node that was or will later be
681 defined with `expand_label'. */
691 expand_goto_internal (label, label_rtx (label), NULL_RTX);
695 /* Check for a nonlocal goto to a containing function. */
696 context = decl_function_context (label);
697 if (context != 0 && context != current_function_decl)
699 struct function *p = find_function_data (context);
700 rtx label_ref = gen_rtx (LABEL_REF, Pmode, label_rtx (label));
703 p->has_nonlocal_label = 1;
704 current_function_has_nonlocal_goto = 1;
705 LABEL_REF_NONLOCAL_P (label_ref) = 1;
707 /* Copy the rtl for the slots so that they won't be shared in
708 case the virtual stack vars register gets instantiated differently
709 in the parent than in the child. */
711 #if HAVE_nonlocal_goto
712 if (HAVE_nonlocal_goto)
713 emit_insn (gen_nonlocal_goto (lookup_static_chain (label),
714 copy_rtx (p->nonlocal_goto_handler_slot),
715 copy_rtx (p->nonlocal_goto_stack_level),
722 /* Restore frame pointer for containing function.
723 This sets the actual hard register used for the frame pointer
724 to the location of the function's incoming static chain info.
725 The non-local goto handler will then adjust it to contain the
726 proper value and reload the argument pointer, if needed. */
727 emit_move_insn (hard_frame_pointer_rtx, lookup_static_chain (label));
729 /* We have now loaded the frame pointer hardware register with
730 the address of that corresponds to the start of the virtual
731 stack vars. So replace virtual_stack_vars_rtx in all
732 addresses we use with stack_pointer_rtx. */
734 /* Get addr of containing function's current nonlocal goto handler,
735 which will do any cleanups and then jump to the label. */
736 addr = copy_rtx (p->nonlocal_goto_handler_slot);
737 temp = copy_to_reg (replace_rtx (addr, virtual_stack_vars_rtx,
738 hard_frame_pointer_rtx));
740 /* Restore the stack pointer. Note this uses fp just restored. */
741 addr = p->nonlocal_goto_stack_level;
743 addr = replace_rtx (copy_rtx (addr),
744 virtual_stack_vars_rtx,
745 hard_frame_pointer_rtx);
747 emit_stack_restore (SAVE_NONLOCAL, addr, NULL_RTX);
749 /* Put in the static chain register the nonlocal label address. */
750 emit_move_insn (static_chain_rtx, label_ref);
751 /* USE of hard_frame_pointer_rtx added for consistency; not clear if
753 emit_insn (gen_rtx (USE, VOIDmode, hard_frame_pointer_rtx));
754 emit_insn (gen_rtx (USE, VOIDmode, stack_pointer_rtx));
755 emit_insn (gen_rtx (USE, VOIDmode, static_chain_rtx));
756 emit_indirect_jump (temp);
760 expand_goto_internal (label, label_rtx (label), NULL_RTX);
763 /* Generate RTL code for a `goto' statement with target label BODY.
764 LABEL should be a LABEL_REF.
765 LAST_INSN, if non-0, is the rtx we should consider as the last
766 insn emitted (for the purposes of cleaning up a return). */
769 expand_goto_internal (body, label, last_insn)
774 struct nesting *block;
777 /* NOTICE! If a bytecode instruction other than `jump' is needed,
778 then the caller has to call bc_expand_goto_internal()
779 directly. This is rather an exceptional case, and there aren't
780 that many places where this is necessary. */
783 expand_goto_internal (body, label, last_insn);
787 if (GET_CODE (label) != CODE_LABEL)
790 /* If label has already been defined, we can tell now
791 whether and how we must alter the stack level. */
793 if (PREV_INSN (label) != 0)
795 /* Find the innermost pending block that contains the label.
796 (Check containment by comparing insn-uids.)
797 Then restore the outermost stack level within that block,
798 and do cleanups of all blocks contained in it. */
799 for (block = block_stack; block; block = block->next)
801 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
803 if (block->data.block.stack_level != 0)
804 stack_level = block->data.block.stack_level;
805 /* Execute the cleanups for blocks we are exiting. */
806 if (block->data.block.cleanups != 0)
808 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
809 do_pending_stack_adjust ();
815 /* Ensure stack adjust isn't done by emit_jump, as this would clobber
816 the stack pointer. This one should be deleted as dead by flow. */
817 clear_pending_stack_adjust ();
818 do_pending_stack_adjust ();
819 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
822 if (body != 0 && DECL_TOO_LATE (body))
823 error ("jump to `%s' invalidly jumps into binding contour",
824 IDENTIFIER_POINTER (DECL_NAME (body)));
826 /* Label not yet defined: may need to put this goto
827 on the fixup list. */
828 else if (! expand_fixup (body, label, last_insn))
830 /* No fixup needed. Record that the label is the target
831 of at least one goto that has no fixup. */
833 TREE_ADDRESSABLE (body) = 1;
839 /* Generate a jump with OPCODE to the given bytecode LABEL which is
840 found within BODY. */
843 bc_expand_goto_internal (opcode, label, body)
844 enum bytecode_opcode opcode;
845 struct bc_label *label;
848 struct nesting *block;
849 int stack_level = -1;
851 /* If the label is defined, adjust the stack as necessary.
852 If it's not defined, we have to push the reference on the
858 /* Find the innermost pending block that contains the label.
859 (Check containment by comparing bytecode uids.) Then restore the
860 outermost stack level within that block. */
862 for (block = block_stack; block; block = block->next)
864 if (BYTECODE_BC_LABEL (block->data.block.first_insn)->uid < label->uid)
866 if (block->data.block.bc_stack_level)
867 stack_level = block->data.block.bc_stack_level;
869 /* Execute the cleanups for blocks we are exiting. */
870 if (block->data.block.cleanups != 0)
872 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
873 do_pending_stack_adjust ();
877 /* Restore the stack level. If we need to adjust the stack, we
878 must do so after the jump, since the jump may depend on
879 what's on the stack. Thus, any stack-modifying conditional
880 jumps (these are the only ones that rely on what's on the
881 stack) go into the fixup list. */
884 && stack_depth != stack_level
887 bc_expand_fixup (opcode, label, stack_level);
890 if (stack_level >= 0)
891 bc_adjust_stack (stack_depth - stack_level);
893 if (body && DECL_BIT_FIELD (body))
894 error ("jump to `%s' invalidly jumps into binding contour",
895 IDENTIFIER_POINTER (DECL_NAME (body)));
897 /* Emit immediate jump */
898 bc_emit_bytecode (opcode);
899 bc_emit_bytecode_labelref (label);
901 #ifdef DEBUG_PRINT_CODE
902 fputc ('\n', stderr);
907 /* Put goto in the fixup list */
908 bc_expand_fixup (opcode, label, stack_level);
911 /* Generate if necessary a fixup for a goto
912 whose target label in tree structure (if any) is TREE_LABEL
913 and whose target in rtl is RTL_LABEL.
915 If LAST_INSN is nonzero, we pretend that the jump appears
916 after insn LAST_INSN instead of at the current point in the insn stream.
918 The fixup will be used later to insert insns just before the goto.
919 Those insns will restore the stack level as appropriate for the
920 target label, and will (in the case of C++) also invoke any object
921 destructors which have to be invoked when we exit the scopes which
922 are exited by the goto.
924 Value is nonzero if a fixup is made. */
927 expand_fixup (tree_label, rtl_label, last_insn)
932 struct nesting *block, *end_block;
934 /* See if we can recognize which block the label will be output in.
935 This is possible in some very common cases.
936 If we succeed, set END_BLOCK to that block.
937 Otherwise, set it to 0. */
940 && (rtl_label == cond_stack->data.cond.endif_label
941 || rtl_label == cond_stack->data.cond.next_label))
942 end_block = cond_stack;
943 /* If we are in a loop, recognize certain labels which
944 are likely targets. This reduces the number of fixups
945 we need to create. */
947 && (rtl_label == loop_stack->data.loop.start_label
948 || rtl_label == loop_stack->data.loop.end_label
949 || rtl_label == loop_stack->data.loop.continue_label))
950 end_block = loop_stack;
954 /* Now set END_BLOCK to the binding level to which we will return. */
958 struct nesting *next_block = end_block->all;
961 /* First see if the END_BLOCK is inside the innermost binding level.
962 If so, then no cleanups or stack levels are relevant. */
963 while (next_block && next_block != block)
964 next_block = next_block->all;
969 /* Otherwise, set END_BLOCK to the innermost binding level
970 which is outside the relevant control-structure nesting. */
971 next_block = block_stack->next;
972 for (block = block_stack; block != end_block; block = block->all)
973 if (block == next_block)
974 next_block = next_block->next;
975 end_block = next_block;
978 /* Does any containing block have a stack level or cleanups?
979 If not, no fixup is needed, and that is the normal case
980 (the only case, for standard C). */
981 for (block = block_stack; block != end_block; block = block->next)
982 if (block->data.block.stack_level != 0
983 || block->data.block.cleanups != 0)
986 if (block != end_block)
988 /* Ok, a fixup is needed. Add a fixup to the list of such. */
989 struct goto_fixup *fixup
990 = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
991 /* In case an old stack level is restored, make sure that comes
992 after any pending stack adjust. */
993 /* ?? If the fixup isn't to come at the present position,
994 doing the stack adjust here isn't useful. Doing it with our
995 settings at that location isn't useful either. Let's hope
998 do_pending_stack_adjust ();
999 fixup->target = tree_label;
1000 fixup->target_rtl = rtl_label;
1002 /* Create a BLOCK node and a corresponding matched set of
1003 NOTE_INSN_BEGIN_BLOCK and NOTE_INSN_END_BLOCK notes at
1004 this point. The notes will encapsulate any and all fixup
1005 code which we might later insert at this point in the insn
1006 stream. Also, the BLOCK node will be the parent (i.e. the
1007 `SUPERBLOCK') of any other BLOCK nodes which we might create
1008 later on when we are expanding the fixup code. */
1011 register rtx original_before_jump
1012 = last_insn ? last_insn : get_last_insn ();
1016 fixup->before_jump = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
1017 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
1018 fixup->context = poplevel (1, 0, 0); /* Create the BLOCK node now! */
1020 emit_insns_after (fixup->before_jump, original_before_jump);
1023 fixup->block_start_count = block_start_count;
1024 fixup->stack_level = 0;
1025 fixup->cleanup_list_list
1026 = (((block->data.block.outer_cleanups
1028 && block->data.block.outer_cleanups != empty_cleanup_list
1031 || block->data.block.cleanups)
1032 ? tree_cons (NULL_TREE, block->data.block.cleanups,
1033 block->data.block.outer_cleanups)
1035 fixup->next = goto_fixup_chain;
1036 goto_fixup_chain = fixup;
1043 /* Generate bytecode jump with OPCODE to a fixup routine that links to LABEL.
1044 Make the fixup restore the stack level to STACK_LEVEL. */
1047 bc_expand_fixup (opcode, label, stack_level)
1048 enum bytecode_opcode opcode;
1049 struct bc_label *label;
1052 struct goto_fixup *fixup
1053 = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
1055 fixup->label = bc_get_bytecode_label ();
1056 fixup->bc_target = label;
1057 fixup->bc_stack_level = stack_level;
1058 fixup->bc_handled = FALSE;
1060 fixup->next = goto_fixup_chain;
1061 goto_fixup_chain = fixup;
1063 /* Insert a jump to the fixup code */
1064 bc_emit_bytecode (opcode);
1065 bc_emit_bytecode_labelref (fixup->label);
1067 #ifdef DEBUG_PRINT_CODE
1068 fputc ('\n', stderr);
1072 /* Expand any needed fixups in the outputmost binding level of the
1073 function. FIRST_INSN is the first insn in the function. */
1076 expand_fixups (first_insn)
1079 fixup_gotos (NULL_PTR, NULL_RTX, NULL_TREE, first_insn, 0);
1082 /* When exiting a binding contour, process all pending gotos requiring fixups.
1083 THISBLOCK is the structure that describes the block being exited.
1084 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
1085 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
1086 FIRST_INSN is the insn that began this contour.
1088 Gotos that jump out of this contour must restore the
1089 stack level and do the cleanups before actually jumping.
1091 DONT_JUMP_IN nonzero means report error there is a jump into this
1092 contour from before the beginning of the contour.
1093 This is also done if STACK_LEVEL is nonzero. */
1096 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
1097 struct nesting *thisblock;
1103 register struct goto_fixup *f, *prev;
1105 if (output_bytecode)
1107 /* ??? The second arg is the bc stack level, which is not the same
1108 as STACK_LEVEL. I have no idea what should go here, so I'll
1110 bc_fixup_gotos (thisblock, 0, cleanup_list, first_insn, dont_jump_in);
1114 /* F is the fixup we are considering; PREV is the previous one. */
1115 /* We run this loop in two passes so that cleanups of exited blocks
1116 are run first, and blocks that are exited are marked so
1119 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1121 /* Test for a fixup that is inactive because it is already handled. */
1122 if (f->before_jump == 0)
1124 /* Delete inactive fixup from the chain, if that is easy to do. */
1126 prev->next = f->next;
1128 /* Has this fixup's target label been defined?
1129 If so, we can finalize it. */
1130 else if (PREV_INSN (f->target_rtl) != 0)
1132 register rtx cleanup_insns;
1134 /* Get the first non-label after the label
1135 this goto jumps to. If that's before this scope begins,
1136 we don't have a jump into the scope. */
1137 rtx after_label = f->target_rtl;
1138 while (after_label != 0 && GET_CODE (after_label) == CODE_LABEL)
1139 after_label = NEXT_INSN (after_label);
1141 /* If this fixup jumped into this contour from before the beginning
1142 of this contour, report an error. */
1143 /* ??? Bug: this does not detect jumping in through intermediate
1144 blocks that have stack levels or cleanups.
1145 It detects only a problem with the innermost block
1146 around the label. */
1148 && (dont_jump_in || stack_level || cleanup_list)
1149 /* If AFTER_LABEL is 0, it means the jump goes to the end
1150 of the rtl, which means it jumps into this scope. */
1151 && (after_label == 0
1152 || INSN_UID (first_insn) < INSN_UID (after_label))
1153 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
1154 && ! DECL_REGISTER (f->target))
1156 error_with_decl (f->target,
1157 "label `%s' used before containing binding contour");
1158 /* Prevent multiple errors for one label. */
1159 DECL_REGISTER (f->target) = 1;
1162 /* We will expand the cleanups into a sequence of their own and
1163 then later on we will attach this new sequence to the insn
1164 stream just ahead of the actual jump insn. */
1168 /* Temporarily restore the lexical context where we will
1169 logically be inserting the fixup code. We do this for the
1170 sake of getting the debugging information right. */
1173 set_block (f->context);
1175 /* Expand the cleanups for blocks this jump exits. */
1176 if (f->cleanup_list_list)
1179 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1180 /* Marked elements correspond to blocks that have been closed.
1181 Do their cleanups. */
1182 if (TREE_ADDRESSABLE (lists)
1183 && TREE_VALUE (lists) != 0)
1185 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1186 /* Pop any pushes done in the cleanups,
1187 in case function is about to return. */
1188 do_pending_stack_adjust ();
1192 /* Restore stack level for the biggest contour that this
1193 jump jumps out of. */
1195 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1197 /* Finish up the sequence containing the insns which implement the
1198 necessary cleanups, and then attach that whole sequence to the
1199 insn stream just ahead of the actual jump insn. Attaching it
1200 at that point insures that any cleanups which are in fact
1201 implicit C++ object destructions (which must be executed upon
1202 leaving the block) appear (to the debugger) to be taking place
1203 in an area of the generated code where the object(s) being
1204 destructed are still "in scope". */
1206 cleanup_insns = get_insns ();
1210 emit_insns_after (cleanup_insns, f->before_jump);
1217 /* For any still-undefined labels, do the cleanups for this block now.
1218 We must do this now since items in the cleanup list may go out
1219 of scope when the block ends. */
1220 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1221 if (f->before_jump != 0
1222 && PREV_INSN (f->target_rtl) == 0
1223 /* Label has still not appeared. If we are exiting a block with
1224 a stack level to restore, that started before the fixup,
1225 mark this stack level as needing restoration
1226 when the fixup is later finalized. */
1228 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1229 means the label is undefined. That's erroneous, but possible. */
1230 && (thisblock->data.block.block_start_count
1231 <= f->block_start_count))
1233 tree lists = f->cleanup_list_list;
1236 for (; lists; lists = TREE_CHAIN (lists))
1237 /* If the following elt. corresponds to our containing block
1238 then the elt. must be for this block. */
1239 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1243 set_block (f->context);
1244 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1245 do_pending_stack_adjust ();
1246 cleanup_insns = get_insns ();
1250 = emit_insns_after (cleanup_insns, f->before_jump);
1252 TREE_VALUE (lists) = 0;
1256 f->stack_level = stack_level;
1261 /* When exiting a binding contour, process all pending gotos requiring fixups.
1262 Note: STACK_DEPTH is not altered.
1264 The arguments are currently not used in the bytecode compiler, but we may
1265 need them one day for languages other than C.
1267 THISBLOCK is the structure that describes the block being exited.
1268 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
1269 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
1270 FIRST_INSN is the insn that began this contour.
1272 Gotos that jump out of this contour must restore the
1273 stack level and do the cleanups before actually jumping.
1275 DONT_JUMP_IN nonzero means report error there is a jump into this
1276 contour from before the beginning of the contour.
1277 This is also done if STACK_LEVEL is nonzero. */
1280 bc_fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
1281 struct nesting *thisblock;
1287 register struct goto_fixup *f, *prev;
1288 int saved_stack_depth;
1290 /* F is the fixup we are considering; PREV is the previous one. */
1292 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1294 /* Test for a fixup that is inactive because it is already handled. */
1295 if (f->before_jump == 0)
1297 /* Delete inactive fixup from the chain, if that is easy to do. */
1299 prev->next = f->next;
1302 /* Emit code to restore the stack and continue */
1303 bc_emit_bytecode_labeldef (f->label);
1305 /* Save stack_depth across call, since bc_adjust_stack () will alter
1306 the perceived stack depth via the instructions generated. */
1308 if (f->bc_stack_level >= 0)
1310 saved_stack_depth = stack_depth;
1311 bc_adjust_stack (stack_depth - f->bc_stack_level);
1312 stack_depth = saved_stack_depth;
1315 bc_emit_bytecode (jump);
1316 bc_emit_bytecode_labelref (f->bc_target);
1318 #ifdef DEBUG_PRINT_CODE
1319 fputc ('\n', stderr);
1323 goto_fixup_chain = NULL;
1326 /* Generate RTL for an asm statement (explicit assembler code).
1327 BODY is a STRING_CST node containing the assembler code text,
1328 or an ADDR_EXPR containing a STRING_CST. */
1334 if (output_bytecode)
1336 error ("`asm' is invalid when generating bytecode");
1340 if (TREE_CODE (body) == ADDR_EXPR)
1341 body = TREE_OPERAND (body, 0);
1343 emit_insn (gen_rtx (ASM_INPUT, VOIDmode,
1344 TREE_STRING_POINTER (body)));
1348 /* Generate RTL for an asm statement with arguments.
1349 STRING is the instruction template.
1350 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1351 Each output or input has an expression in the TREE_VALUE and
1352 a constraint-string in the TREE_PURPOSE.
1353 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1354 that is clobbered by this insn.
1356 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1357 Some elements of OUTPUTS may be replaced with trees representing temporary
1358 values. The caller should copy those temporary values to the originally
1361 VOL nonzero means the insn is volatile; don't optimize it. */
1364 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1365 tree string, outputs, inputs, clobbers;
1370 rtvec argvec, constraints;
1372 int ninputs = list_length (inputs);
1373 int noutputs = list_length (outputs);
1377 /* Vector of RTX's of evaluated output operands. */
1378 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1379 /* The insn we have emitted. */
1382 if (output_bytecode)
1384 error ("`asm' is invalid when generating bytecode");
1388 /* Count the number of meaningful clobbered registers, ignoring what
1389 we would ignore later. */
1391 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1393 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1394 i = decode_reg_name (regname);
1395 if (i >= 0 || i == -4)
1398 error ("unknown register name `%s' in `asm'", regname);
1403 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1405 tree val = TREE_VALUE (tail);
1410 /* If there's an erroneous arg, emit no insn. */
1411 if (TREE_TYPE (val) == error_mark_node)
1414 /* Make sure constraint has `=' and does not have `+'. */
1417 for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1419 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1421 error ("output operand constraint contains `+'");
1424 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '=')
1429 error ("output operand constraint lacks `='");
1433 /* If an output operand is not a variable or indirect ref,
1435 create a SAVE_EXPR which is a pseudo-reg
1436 to act as an intermediate temporary.
1437 Make the asm insn write into that, then copy it to
1438 the real output operand. */
1440 while (TREE_CODE (val) == COMPONENT_REF
1441 || TREE_CODE (val) == ARRAY_REF)
1442 val = TREE_OPERAND (val, 0);
1444 if (TREE_CODE (val) != VAR_DECL
1445 && TREE_CODE (val) != PARM_DECL
1446 && TREE_CODE (val) != INDIRECT_REF)
1448 TREE_VALUE (tail) = save_expr (TREE_VALUE (tail));
1449 /* If it's a constant, print error now so don't crash later. */
1450 if (TREE_CODE (TREE_VALUE (tail)) != SAVE_EXPR)
1452 error ("invalid output in `asm'");
1457 output_rtx[i] = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1460 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1462 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1466 /* Make vectors for the expression-rtx and constraint strings. */
1468 argvec = rtvec_alloc (ninputs);
1469 constraints = rtvec_alloc (ninputs);
1471 body = gen_rtx (ASM_OPERANDS, VOIDmode,
1472 TREE_STRING_POINTER (string), "", 0, argvec, constraints,
1474 MEM_VOLATILE_P (body) = vol;
1476 /* Eval the inputs and put them into ARGVEC.
1477 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1480 for (tail = inputs; tail; tail = TREE_CHAIN (tail))
1484 /* If there's an erroneous arg, emit no insn,
1485 because the ASM_INPUT would get VOIDmode
1486 and that could cause a crash in reload. */
1487 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1489 if (TREE_PURPOSE (tail) == NULL_TREE)
1491 error ("hard register `%s' listed as input operand to `asm'",
1492 TREE_STRING_POINTER (TREE_VALUE (tail)) );
1496 /* Make sure constraint has neither `=' nor `+'. */
1498 for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1499 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '='
1500 || TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1502 error ("input operand constraint contains `%c'",
1503 TREE_STRING_POINTER (TREE_PURPOSE (tail))[j]);
1507 XVECEXP (body, 3, i) /* argvec */
1508 = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1509 if (CONSTANT_P (XVECEXP (body, 3, i))
1510 && ! general_operand (XVECEXP (body, 3, i),
1511 TYPE_MODE (TREE_TYPE (TREE_VALUE (tail)))))
1512 XVECEXP (body, 3, i)
1513 = force_reg (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1514 XVECEXP (body, 3, i));
1515 XVECEXP (body, 4, i) /* constraints */
1516 = gen_rtx (ASM_INPUT, TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1517 TREE_STRING_POINTER (TREE_PURPOSE (tail)));
1521 /* Protect all the operands from the queue,
1522 now that they have all been evaluated. */
1524 for (i = 0; i < ninputs; i++)
1525 XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
1527 for (i = 0; i < noutputs; i++)
1528 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1530 /* Now, for each output, construct an rtx
1531 (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
1532 ARGVEC CONSTRAINTS))
1533 If there is more than one, put them inside a PARALLEL. */
1535 if (noutputs == 1 && nclobbers == 0)
1537 XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
1538 insn = emit_insn (gen_rtx (SET, VOIDmode, output_rtx[0], body));
1540 else if (noutputs == 0 && nclobbers == 0)
1542 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1543 insn = emit_insn (body);
1549 if (num == 0) num = 1;
1550 body = gen_rtx (PARALLEL, VOIDmode, rtvec_alloc (num + nclobbers));
1552 /* For each output operand, store a SET. */
1554 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1556 XVECEXP (body, 0, i)
1557 = gen_rtx (SET, VOIDmode,
1559 gen_rtx (ASM_OPERANDS, VOIDmode,
1560 TREE_STRING_POINTER (string),
1561 TREE_STRING_POINTER (TREE_PURPOSE (tail)),
1562 i, argvec, constraints,
1564 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1567 /* If there are no outputs (but there are some clobbers)
1568 store the bare ASM_OPERANDS into the PARALLEL. */
1571 XVECEXP (body, 0, i++) = obody;
1573 /* Store (clobber REG) for each clobbered register specified. */
1575 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1577 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1578 int j = decode_reg_name (regname);
1582 if (j == -3) /* `cc', which is not a register */
1585 if (j == -4) /* `memory', don't cache memory across asm */
1587 XVECEXP (body, 0, i++)
1588 = gen_rtx (CLOBBER, VOIDmode,
1589 gen_rtx (MEM, BLKmode,
1590 gen_rtx (SCRATCH, VOIDmode, 0)));
1594 /* Ignore unknown register, error already signalled. */
1597 /* Use QImode since that's guaranteed to clobber just one reg. */
1598 XVECEXP (body, 0, i++)
1599 = gen_rtx (CLOBBER, VOIDmode, gen_rtx (REG, QImode, j));
1602 insn = emit_insn (body);
1608 /* Generate RTL to evaluate the expression EXP
1609 and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
1612 expand_expr_stmt (exp)
1615 if (output_bytecode)
1617 int org_stack_depth = stack_depth;
1619 bc_expand_expr (exp);
1621 /* Restore stack depth */
1622 if (stack_depth < org_stack_depth)
1625 bc_emit_instruction (drop);
1627 last_expr_type = TREE_TYPE (exp);
1631 /* If -W, warn about statements with no side effects,
1632 except for an explicit cast to void (e.g. for assert()), and
1633 except inside a ({...}) where they may be useful. */
1634 if (expr_stmts_for_value == 0 && exp != error_mark_node)
1636 if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
1637 && !(TREE_CODE (exp) == CONVERT_EXPR
1638 && TREE_TYPE (exp) == void_type_node))
1639 warning_with_file_and_line (emit_filename, emit_lineno,
1640 "statement with no effect");
1641 else if (warn_unused)
1642 warn_if_unused_value (exp);
1645 /* If EXP is of function type and we are expanding statements for
1646 value, convert it to pointer-to-function. */
1647 if (expr_stmts_for_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
1648 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
1650 last_expr_type = TREE_TYPE (exp);
1651 if (! flag_syntax_only)
1652 last_expr_value = expand_expr (exp,
1653 (expr_stmts_for_value
1654 ? NULL_RTX : const0_rtx),
1657 /* If all we do is reference a volatile value in memory,
1658 copy it to a register to be sure it is actually touched. */
1659 if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
1660 && TREE_THIS_VOLATILE (exp))
1662 if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
1664 else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
1665 copy_to_reg (last_expr_value);
1668 rtx lab = gen_label_rtx ();
1670 /* Compare the value with itself to reference it. */
1671 emit_cmp_insn (last_expr_value, last_expr_value, EQ,
1672 expand_expr (TYPE_SIZE (last_expr_type),
1673 NULL_RTX, VOIDmode, 0),
1675 TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT);
1676 emit_jump_insn ((*bcc_gen_fctn[(int) EQ]) (lab));
1681 /* If this expression is part of a ({...}) and is in memory, we may have
1682 to preserve temporaries. */
1683 preserve_temp_slots (last_expr_value);
1685 /* Free any temporaries used to evaluate this expression. Any temporary
1686 used as a result of this expression will already have been preserved
1693 /* Warn if EXP contains any computations whose results are not used.
1694 Return 1 if a warning is printed; 0 otherwise. */
1697 warn_if_unused_value (exp)
1700 if (TREE_USED (exp))
1703 switch (TREE_CODE (exp))
1705 case PREINCREMENT_EXPR:
1706 case POSTINCREMENT_EXPR:
1707 case PREDECREMENT_EXPR:
1708 case POSTDECREMENT_EXPR:
1713 case METHOD_CALL_EXPR:
1715 case WITH_CLEANUP_EXPR:
1717 /* We don't warn about COND_EXPR because it may be a useful
1718 construct if either arm contains a side effect. */
1723 /* For a binding, warn if no side effect within it. */
1724 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1727 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1729 case TRUTH_ORIF_EXPR:
1730 case TRUTH_ANDIF_EXPR:
1731 /* In && or ||, warn if 2nd operand has no side effect. */
1732 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1735 if (TREE_NO_UNUSED_WARNING (exp))
1737 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
1739 /* Let people do `(foo (), 0)' without a warning. */
1740 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1742 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1746 case NON_LVALUE_EXPR:
1747 /* Don't warn about values cast to void. */
1748 if (TREE_TYPE (exp) == void_type_node)
1750 /* Don't warn about conversions not explicit in the user's program. */
1751 if (TREE_NO_UNUSED_WARNING (exp))
1753 /* Assignment to a cast usually results in a cast of a modify.
1754 Don't complain about that. There can be an arbitrary number of
1755 casts before the modify, so we must loop until we find the first
1756 non-cast expression and then test to see if that is a modify. */
1758 tree tem = TREE_OPERAND (exp, 0);
1760 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1761 tem = TREE_OPERAND (tem, 0);
1763 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
1764 || TREE_CODE (tem) == CALL_EXPR)
1770 /* Don't warn about automatic dereferencing of references, since
1771 the user cannot control it. */
1772 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
1773 return warn_if_unused_value (TREE_OPERAND (exp, 0));
1774 /* ... fall through ... */
1777 /* Referencing a volatile value is a side effect, so don't warn. */
1778 if ((TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
1779 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1780 && TREE_THIS_VOLATILE (exp))
1783 warning_with_file_and_line (emit_filename, emit_lineno,
1784 "value computed is not used");
1789 /* Clear out the memory of the last expression evaluated. */
1797 /* Begin a statement which will return a value.
1798 Return the RTL_EXPR for this statement expr.
1799 The caller must save that value and pass it to expand_end_stmt_expr. */
1802 expand_start_stmt_expr ()
1807 /* When generating bytecode just note down the stack depth */
1808 if (output_bytecode)
1809 return (build_int_2 (stack_depth, 0));
1811 /* Make the RTL_EXPR node temporary, not momentary,
1812 so that rtl_expr_chain doesn't become garbage. */
1813 momentary = suspend_momentary ();
1814 t = make_node (RTL_EXPR);
1815 resume_momentary (momentary);
1816 start_sequence_for_rtl_expr (t);
1818 expr_stmts_for_value++;
1822 /* Restore the previous state at the end of a statement that returns a value.
1823 Returns a tree node representing the statement's value and the
1824 insns to compute the value.
1826 The nodes of that expression have been freed by now, so we cannot use them.
1827 But we don't want to do that anyway; the expression has already been
1828 evaluated and now we just want to use the value. So generate a RTL_EXPR
1829 with the proper type and RTL value.
1831 If the last substatement was not an expression,
1832 return something with type `void'. */
1835 expand_end_stmt_expr (t)
1838 if (output_bytecode)
1844 /* At this point, all expressions have been evaluated in order.
1845 However, all expression values have been popped when evaluated,
1846 which means we have to recover the last expression value. This is
1847 the last value removed by means of a `drop' instruction. Instead
1848 of adding code to inhibit dropping the last expression value, it
1849 is here recovered by undoing the `drop'. Since `drop' is
1850 equivalent to `adjustackSI [1]', it can be undone with `adjstackSI
1853 bc_adjust_stack (-1);
1855 if (!last_expr_type)
1856 last_expr_type = void_type_node;
1858 t = make_node (RTL_EXPR);
1859 TREE_TYPE (t) = last_expr_type;
1860 RTL_EXPR_RTL (t) = NULL;
1861 RTL_EXPR_SEQUENCE (t) = NULL;
1863 /* Don't consider deleting this expr or containing exprs at tree level. */
1864 TREE_THIS_VOLATILE (t) = 1;
1872 if (last_expr_type == 0)
1874 last_expr_type = void_type_node;
1875 last_expr_value = const0_rtx;
1877 else if (last_expr_value == 0)
1878 /* There are some cases where this can happen, such as when the
1879 statement is void type. */
1880 last_expr_value = const0_rtx;
1881 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
1882 /* Remove any possible QUEUED. */
1883 last_expr_value = protect_from_queue (last_expr_value, 0);
1887 TREE_TYPE (t) = last_expr_type;
1888 RTL_EXPR_RTL (t) = last_expr_value;
1889 RTL_EXPR_SEQUENCE (t) = get_insns ();
1891 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
1895 /* Don't consider deleting this expr or containing exprs at tree level. */
1896 TREE_SIDE_EFFECTS (t) = 1;
1897 /* Propagate volatility of the actual RTL expr. */
1898 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
1901 expr_stmts_for_value--;
1906 /* Generate RTL for the start of an if-then. COND is the expression
1907 whose truth should be tested.
1909 If EXITFLAG is nonzero, this conditional is visible to
1910 `exit_something'. */
1913 expand_start_cond (cond, exitflag)
1917 struct nesting *thiscond = ALLOC_NESTING ();
1919 /* Make an entry on cond_stack for the cond we are entering. */
1921 thiscond->next = cond_stack;
1922 thiscond->all = nesting_stack;
1923 thiscond->depth = ++nesting_depth;
1924 thiscond->data.cond.next_label = gen_label_rtx ();
1925 /* Before we encounter an `else', we don't need a separate exit label
1926 unless there are supposed to be exit statements
1927 to exit this conditional. */
1928 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
1929 thiscond->data.cond.endif_label = thiscond->exit_label;
1930 cond_stack = thiscond;
1931 nesting_stack = thiscond;
1933 if (output_bytecode)
1934 bc_expand_start_cond (cond, exitflag);
1936 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
1939 /* Generate RTL between then-clause and the elseif-clause
1940 of an if-then-elseif-.... */
1943 expand_start_elseif (cond)
1946 if (cond_stack->data.cond.endif_label == 0)
1947 cond_stack->data.cond.endif_label = gen_label_rtx ();
1948 emit_jump (cond_stack->data.cond.endif_label);
1949 emit_label (cond_stack->data.cond.next_label);
1950 cond_stack->data.cond.next_label = gen_label_rtx ();
1951 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1954 /* Generate RTL between the then-clause and the else-clause
1955 of an if-then-else. */
1958 expand_start_else ()
1960 if (cond_stack->data.cond.endif_label == 0)
1961 cond_stack->data.cond.endif_label = gen_label_rtx ();
1963 if (output_bytecode)
1965 bc_expand_start_else ();
1969 emit_jump (cond_stack->data.cond.endif_label);
1970 emit_label (cond_stack->data.cond.next_label);
1971 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
1974 /* After calling expand_start_else, turn this "else" into an "else if"
1975 by providing another condition. */
1978 expand_elseif (cond)
1981 cond_stack->data.cond.next_label = gen_label_rtx ();
1982 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1985 /* Generate RTL for the end of an if-then.
1986 Pop the record for it off of cond_stack. */
1991 struct nesting *thiscond = cond_stack;
1993 if (output_bytecode)
1994 bc_expand_end_cond ();
1997 do_pending_stack_adjust ();
1998 if (thiscond->data.cond.next_label)
1999 emit_label (thiscond->data.cond.next_label);
2000 if (thiscond->data.cond.endif_label)
2001 emit_label (thiscond->data.cond.endif_label);
2004 POPSTACK (cond_stack);
2009 /* Generate code for the start of an if-then. COND is the expression
2010 whose truth is to be tested; if EXITFLAG is nonzero this conditional
2011 is to be visible to exit_something. It is assumed that the caller
2012 has pushed the previous context on the cond stack. */
2015 bc_expand_start_cond (cond, exitflag)
2019 struct nesting *thiscond = cond_stack;
2021 thiscond->data.case_stmt.nominal_type = cond;
2023 thiscond->exit_label = gen_label_rtx ();
2024 bc_expand_expr (cond);
2025 bc_emit_bytecode (xjumpifnot);
2026 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscond->exit_label));
2028 #ifdef DEBUG_PRINT_CODE
2029 fputc ('\n', stderr);
2033 /* Generate the label for the end of an if with
2037 bc_expand_end_cond ()
2039 struct nesting *thiscond = cond_stack;
2041 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscond->exit_label));
2044 /* Generate code for the start of the else- clause of
2048 bc_expand_start_else ()
2050 struct nesting *thiscond = cond_stack;
2052 thiscond->data.cond.endif_label = thiscond->exit_label;
2053 thiscond->exit_label = gen_label_rtx ();
2054 bc_emit_bytecode (jump);
2055 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscond->exit_label));
2057 #ifdef DEBUG_PRINT_CODE
2058 fputc ('\n', stderr);
2061 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscond->data.cond.endif_label));
2064 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2065 loop should be exited by `exit_something'. This is a loop for which
2066 `expand_continue' will jump to the top of the loop.
2068 Make an entry on loop_stack to record the labels associated with
2072 expand_start_loop (exit_flag)
2075 register struct nesting *thisloop = ALLOC_NESTING ();
2077 /* Make an entry on loop_stack for the loop we are entering. */
2079 thisloop->next = loop_stack;
2080 thisloop->all = nesting_stack;
2081 thisloop->depth = ++nesting_depth;
2082 thisloop->data.loop.start_label = gen_label_rtx ();
2083 thisloop->data.loop.end_label = gen_label_rtx ();
2084 thisloop->data.loop.alt_end_label = 0;
2085 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2086 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2087 loop_stack = thisloop;
2088 nesting_stack = thisloop;
2090 if (output_bytecode)
2092 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisloop->data.loop.start_label));
2096 do_pending_stack_adjust ();
2098 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
2099 emit_label (thisloop->data.loop.start_label);
2104 /* Like expand_start_loop but for a loop where the continuation point
2105 (for expand_continue_loop) will be specified explicitly. */
2108 expand_start_loop_continue_elsewhere (exit_flag)
2111 struct nesting *thisloop = expand_start_loop (exit_flag);
2112 loop_stack->data.loop.continue_label = gen_label_rtx ();
2116 /* Specify the continuation point for a loop started with
2117 expand_start_loop_continue_elsewhere.
2118 Use this at the point in the code to which a continue statement
2122 expand_loop_continue_here ()
2124 if (output_bytecode)
2126 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (loop_stack->data.loop.continue_label));
2129 do_pending_stack_adjust ();
2130 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
2131 emit_label (loop_stack->data.loop.continue_label);
2137 bc_expand_end_loop ()
2139 struct nesting *thisloop = loop_stack;
2141 bc_emit_bytecode (jump);
2142 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thisloop->data.loop.start_label));
2144 #ifdef DEBUG_PRINT_CODE
2145 fputc ('\n', stderr);
2148 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisloop->exit_label));
2149 POPSTACK (loop_stack);
2154 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2155 Pop the block off of loop_stack. */
2161 register rtx start_label;
2162 rtx last_test_insn = 0;
2165 if (output_bytecode)
2167 bc_expand_end_loop ();
2171 insn = get_last_insn ();
2172 start_label = loop_stack->data.loop.start_label;
2174 /* Mark the continue-point at the top of the loop if none elsewhere. */
2175 if (start_label == loop_stack->data.loop.continue_label)
2176 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2178 do_pending_stack_adjust ();
2180 /* If optimizing, perhaps reorder the loop. If the loop
2181 starts with a conditional exit, roll that to the end
2182 where it will optimize together with the jump back.
2184 We look for the last conditional branch to the exit that we encounter
2185 before hitting 30 insns or a CALL_INSN. If we see an unconditional
2186 branch to the exit first, use it.
2188 We must also stop at NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes
2189 because moving them is not valid. */
2193 ! (GET_CODE (insn) == JUMP_INSN
2194 && GET_CODE (PATTERN (insn)) == SET
2195 && SET_DEST (PATTERN (insn)) == pc_rtx
2196 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
2198 /* Scan insns from the top of the loop looking for a qualified
2199 conditional exit. */
2200 for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
2201 insn = NEXT_INSN (insn))
2203 if (GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == CODE_LABEL)
2206 if (GET_CODE (insn) == NOTE
2207 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2208 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2211 if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2214 if (last_test_insn && num_insns > 30)
2217 if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == SET
2218 && SET_DEST (PATTERN (insn)) == pc_rtx
2219 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE
2220 && ((GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == LABEL_REF
2221 && ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
2222 == loop_stack->data.loop.end_label)
2223 || (XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
2224 == loop_stack->data.loop.alt_end_label)))
2225 || (GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 2)) == LABEL_REF
2226 && ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
2227 == loop_stack->data.loop.end_label)
2228 || (XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
2229 == loop_stack->data.loop.alt_end_label)))))
2230 last_test_insn = insn;
2232 if (last_test_insn == 0 && GET_CODE (insn) == JUMP_INSN
2233 && GET_CODE (PATTERN (insn)) == SET
2234 && SET_DEST (PATTERN (insn)) == pc_rtx
2235 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF
2236 && ((XEXP (SET_SRC (PATTERN (insn)), 0)
2237 == loop_stack->data.loop.end_label)
2238 || (XEXP (SET_SRC (PATTERN (insn)), 0)
2239 == loop_stack->data.loop.alt_end_label)))
2240 /* Include BARRIER. */
2241 last_test_insn = NEXT_INSN (insn);
2244 if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2246 /* We found one. Move everything from there up
2247 to the end of the loop, and add a jump into the loop
2248 to jump to there. */
2249 register rtx newstart_label = gen_label_rtx ();
2250 register rtx start_move = start_label;
2252 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2253 then we want to move this note also. */
2254 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2255 && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2256 == NOTE_INSN_LOOP_CONT))
2257 start_move = PREV_INSN (start_move);
2259 emit_label_after (newstart_label, PREV_INSN (start_move));
2260 reorder_insns (start_move, last_test_insn, get_last_insn ());
2261 emit_jump_insn_after (gen_jump (start_label),
2262 PREV_INSN (newstart_label));
2263 emit_barrier_after (PREV_INSN (newstart_label));
2264 start_label = newstart_label;
2268 emit_jump (start_label);
2269 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
2270 emit_label (loop_stack->data.loop.end_label);
2272 POPSTACK (loop_stack);
2277 /* Generate a jump to the current loop's continue-point.
2278 This is usually the top of the loop, but may be specified
2279 explicitly elsewhere. If not currently inside a loop,
2280 return 0 and do nothing; caller will print an error message. */
2283 expand_continue_loop (whichloop)
2284 struct nesting *whichloop;
2288 whichloop = loop_stack;
2291 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2296 /* Generate a jump to exit the current loop. If not currently inside a loop,
2297 return 0 and do nothing; caller will print an error message. */
2300 expand_exit_loop (whichloop)
2301 struct nesting *whichloop;
2305 whichloop = loop_stack;
2308 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2312 /* Generate a conditional jump to exit the current loop if COND
2313 evaluates to zero. If not currently inside a loop,
2314 return 0 and do nothing; caller will print an error message. */
2317 expand_exit_loop_if_false (whichloop, cond)
2318 struct nesting *whichloop;
2323 whichloop = loop_stack;
2326 if (output_bytecode)
2328 bc_expand_expr (cond);
2329 bc_expand_goto_internal (xjumpifnot,
2330 BYTECODE_BC_LABEL (whichloop->exit_label),
2335 /* In order to handle fixups, we actually create a conditional jump
2336 around a unconditional branch to exit the loop. If fixups are
2337 necessary, they go before the unconditional branch. */
2339 rtx label = gen_label_rtx ();
2342 do_jump (cond, NULL_RTX, label);
2343 last_insn = get_last_insn ();
2344 if (GET_CODE (last_insn) == CODE_LABEL)
2345 whichloop->data.loop.alt_end_label = last_insn;
2346 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2354 /* Return non-zero if we should preserve sub-expressions as separate
2355 pseudos. We never do so if we aren't optimizing. We always do so
2356 if -fexpensive-optimizations.
2358 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2359 the loop may still be a small one. */
2362 preserve_subexpressions_p ()
2366 if (flag_expensive_optimizations)
2369 if (optimize == 0 || loop_stack == 0)
2372 insn = get_last_insn_anywhere ();
2375 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2376 < n_non_fixed_regs * 3));
2380 /* Generate a jump to exit the current loop, conditional, binding contour
2381 or case statement. Not all such constructs are visible to this function,
2382 only those started with EXIT_FLAG nonzero. Individual languages use
2383 the EXIT_FLAG parameter to control which kinds of constructs you can
2386 If not currently inside anything that can be exited,
2387 return 0 and do nothing; caller will print an error message. */
2390 expand_exit_something ()
2394 for (n = nesting_stack; n; n = n->all)
2395 if (n->exit_label != 0)
2397 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2404 /* Generate RTL to return from the current function, with no value.
2405 (That is, we do not do anything about returning any value.) */
2408 expand_null_return ()
2410 struct nesting *block = block_stack;
2413 if (output_bytecode)
2415 bc_emit_instruction (ret);
2419 /* Does any pending block have cleanups? */
2421 while (block && block->data.block.cleanups == 0)
2422 block = block->next;
2424 /* If yes, use a goto to return, since that runs cleanups. */
2426 expand_null_return_1 (last_insn, block != 0);
2429 /* Generate RTL to return from the current function, with value VAL. */
2432 expand_value_return (val)
2435 struct nesting *block = block_stack;
2436 rtx last_insn = get_last_insn ();
2437 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2439 /* Copy the value to the return location
2440 unless it's already there. */
2442 if (return_reg != val)
2444 #ifdef PROMOTE_FUNCTION_RETURN
2445 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2446 int unsignedp = TREE_UNSIGNED (type);
2447 enum machine_mode mode
2448 = promote_mode (type, DECL_MODE (DECL_RESULT (current_function_decl)),
2451 if (GET_MODE (val) != VOIDmode && GET_MODE (val) != mode)
2452 convert_move (return_reg, val, unsignedp);
2455 emit_move_insn (return_reg, val);
2457 if (GET_CODE (return_reg) == REG
2458 && REGNO (return_reg) < FIRST_PSEUDO_REGISTER)
2459 emit_insn (gen_rtx (USE, VOIDmode, return_reg));
2461 /* Does any pending block have cleanups? */
2463 while (block && block->data.block.cleanups == 0)
2464 block = block->next;
2466 /* If yes, use a goto to return, since that runs cleanups.
2467 Use LAST_INSN to put cleanups *before* the move insn emitted above. */
2469 expand_null_return_1 (last_insn, block != 0);
2472 /* Output a return with no value. If LAST_INSN is nonzero,
2473 pretend that the return takes place after LAST_INSN.
2474 If USE_GOTO is nonzero then don't use a return instruction;
2475 go to the return label instead. This causes any cleanups
2476 of pending blocks to be executed normally. */
2479 expand_null_return_1 (last_insn, use_goto)
2483 rtx end_label = cleanup_label ? cleanup_label : return_label;
2485 clear_pending_stack_adjust ();
2486 do_pending_stack_adjust ();
2489 /* PCC-struct return always uses an epilogue. */
2490 if (current_function_returns_pcc_struct || use_goto)
2493 end_label = return_label = gen_label_rtx ();
2494 expand_goto_internal (NULL_TREE, end_label, last_insn);
2498 /* Otherwise output a simple return-insn if one is available,
2499 unless it won't do the job. */
2501 if (HAVE_return && use_goto == 0 && cleanup_label == 0)
2503 emit_jump_insn (gen_return ());
2509 /* Otherwise jump to the epilogue. */
2510 expand_goto_internal (NULL_TREE, end_label, last_insn);
2513 /* Generate RTL to evaluate the expression RETVAL and return it
2514 from the current function. */
2517 expand_return (retval)
2520 /* If there are any cleanups to be performed, then they will
2521 be inserted following LAST_INSN. It is desirable
2522 that the last_insn, for such purposes, should be the
2523 last insn before computing the return value. Otherwise, cleanups
2524 which call functions can clobber the return value. */
2525 /* ??? rms: I think that is erroneous, because in C++ it would
2526 run destructors on variables that might be used in the subsequent
2527 computation of the return value. */
2529 register rtx val = 0;
2533 struct nesting *block;
2535 /* Bytecode returns are quite simple, just leave the result on the
2536 arithmetic stack. */
2537 if (output_bytecode)
2539 bc_expand_expr (retval);
2540 bc_emit_instruction (ret);
2544 /* If function wants no value, give it none. */
2545 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2547 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2549 expand_null_return ();
2553 /* Are any cleanups needed? E.g. C++ destructors to be run? */
2554 /* This is not sufficient. We also need to watch for cleanups of the
2555 expression we are about to expand. Unfortunately, we cannot know
2556 if it has cleanups until we expand it, and we want to change how we
2557 expand it depending upon if we need cleanups. We can't win. */
2559 cleanups = any_pending_cleanups (1);
2564 if (TREE_CODE (retval) == RESULT_DECL)
2565 retval_rhs = retval;
2566 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2567 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2568 retval_rhs = TREE_OPERAND (retval, 1);
2569 else if (TREE_TYPE (retval) == void_type_node)
2570 /* Recognize tail-recursive call to void function. */
2571 retval_rhs = retval;
2573 retval_rhs = NULL_TREE;
2575 /* Only use `last_insn' if there are cleanups which must be run. */
2576 if (cleanups || cleanup_label != 0)
2577 last_insn = get_last_insn ();
2579 /* Distribute return down conditional expr if either of the sides
2580 may involve tail recursion (see test below). This enhances the number
2581 of tail recursions we see. Don't do this always since it can produce
2582 sub-optimal code in some cases and we distribute assignments into
2583 conditional expressions when it would help. */
2585 if (optimize && retval_rhs != 0
2586 && frame_offset == 0
2587 && TREE_CODE (retval_rhs) == COND_EXPR
2588 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
2589 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
2591 rtx label = gen_label_rtx ();
2594 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
2595 expr = build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2596 DECL_RESULT (current_function_decl),
2597 TREE_OPERAND (retval_rhs, 1));
2598 TREE_SIDE_EFFECTS (expr) = 1;
2599 expand_return (expr);
2602 expr = build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2603 DECL_RESULT (current_function_decl),
2604 TREE_OPERAND (retval_rhs, 2));
2605 TREE_SIDE_EFFECTS (expr) = 1;
2606 expand_return (expr);
2610 /* For tail-recursive call to current function,
2611 just jump back to the beginning.
2612 It's unsafe if any auto variable in this function
2613 has its address taken; for simplicity,
2614 require stack frame to be empty. */
2615 if (optimize && retval_rhs != 0
2616 && frame_offset == 0
2617 && TREE_CODE (retval_rhs) == CALL_EXPR
2618 && TREE_CODE (TREE_OPERAND (retval_rhs, 0)) == ADDR_EXPR
2619 && TREE_OPERAND (TREE_OPERAND (retval_rhs, 0), 0) == current_function_decl
2620 /* Finish checking validity, and if valid emit code
2621 to set the argument variables for the new call. */
2622 && tail_recursion_args (TREE_OPERAND (retval_rhs, 1),
2623 DECL_ARGUMENTS (current_function_decl)))
2625 if (tail_recursion_label == 0)
2627 tail_recursion_label = gen_label_rtx ();
2628 emit_label_after (tail_recursion_label,
2629 tail_recursion_reentry);
2632 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
2637 /* This optimization is safe if there are local cleanups
2638 because expand_null_return takes care of them.
2639 ??? I think it should also be safe when there is a cleanup label,
2640 because expand_null_return takes care of them, too.
2641 Any reason why not? */
2642 if (HAVE_return && cleanup_label == 0
2643 && ! current_function_returns_pcc_struct
2644 && BRANCH_COST <= 1)
2646 /* If this is return x == y; then generate
2647 if (x == y) return 1; else return 0;
2648 if we can do it with explicit return insns and
2649 branches are cheap. */
2651 switch (TREE_CODE (retval_rhs))
2659 case TRUTH_ANDIF_EXPR:
2660 case TRUTH_ORIF_EXPR:
2661 case TRUTH_AND_EXPR:
2663 case TRUTH_NOT_EXPR:
2664 case TRUTH_XOR_EXPR:
2665 op0 = gen_label_rtx ();
2666 jumpifnot (retval_rhs, op0);
2667 expand_value_return (const1_rtx);
2669 expand_value_return (const0_rtx);
2673 #endif /* HAVE_return */
2675 /* If the result is an aggregate that is being returned in one (or more)
2676 registers, load the registers here. The compiler currently can't handle
2677 copying a BLKmode value into registers. We could put this code in a
2678 more general area (for use by everyone instead of just function
2679 call/return), but until this feature is generally usable it is kept here
2680 (and in expand_call). */
2683 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
2684 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2687 int big_endian_correction = 0;
2688 int bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2689 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2690 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
2691 rtx result_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2692 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2693 enum machine_mode tmpmode;
2695 /* Structures smaller than a word are aligned to the least significant
2696 byte (to the right). On a BYTES_BIG_ENDIAN machine, this means we
2697 must skip the empty high order bytes when calculating the bit
2699 if (BYTES_BIG_ENDIAN && bytes < UNITS_PER_WORD)
2700 big_endian_correction = (BITS_PER_WORD - (bytes * BITS_PER_UNIT));
2702 for (i = 0; i < n_regs; i++)
2704 rtx reg = gen_reg_rtx (word_mode);
2705 rtx word = operand_subword_force (result_val, i, BLKmode);
2706 int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)),BITS_PER_WORD);
2709 result_pseudos[i] = reg;
2711 /* Clobber REG and move each partword into it. Ensure we don't
2712 go past the end of the structure. Note that the loop below
2713 works because we've already verified that padding and
2714 endianness are compatable. */
2715 emit_insn (gen_rtx (CLOBBER, VOIDmode, reg));
2718 bitpos < BITS_PER_WORD && bytes > 0;
2719 bitpos += bitsize, bytes -= bitsize / BITS_PER_UNIT)
2721 int xbitpos = bitpos + big_endian_correction;
2723 store_bit_field (reg, bitsize, xbitpos, word_mode,
2724 extract_bit_field (word, bitsize, bitpos, 1,
2725 NULL_RTX, word_mode,
2727 bitsize / BITS_PER_UNIT,
2729 bitsize / BITS_PER_UNIT, BITS_PER_WORD);
2733 /* Now that the value is in pseudos, copy it to the result reg(s). */
2736 for (i = 0; i < n_regs; i++)
2737 emit_move_insn (gen_rtx (REG, word_mode, REGNO (result_reg) + i),
2740 /* Find the smallest integer mode large enough to hold the
2741 entire structure and use that mode instead of BLKmode
2742 on the USE insn for the return register. */
2743 bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2744 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
2745 tmpmode != MAX_MACHINE_MODE;
2746 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
2748 /* Have we found a large enough mode? */
2749 if (GET_MODE_SIZE (tmpmode) >= bytes)
2753 /* No suitable mode found. */
2754 if (tmpmode == MAX_MACHINE_MODE)
2757 PUT_MODE (result_reg, tmpmode);
2759 expand_value_return (result_reg);
2763 && TREE_TYPE (retval_rhs) != void_type_node
2764 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2766 /* Calculate the return value into a pseudo reg. */
2767 val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2769 /* All temporaries have now been used. */
2771 /* Return the calculated value, doing cleanups first. */
2772 expand_value_return (val);
2776 /* No cleanups or no hard reg used;
2777 calculate value into hard return reg. */
2778 expand_expr (retval, const0_rtx, VOIDmode, 0);
2781 expand_value_return (DECL_RTL (DECL_RESULT (current_function_decl)));
2785 /* Return 1 if the end of the generated RTX is not a barrier.
2786 This means code already compiled can drop through. */
2789 drop_through_at_end_p ()
2791 rtx insn = get_last_insn ();
2792 while (insn && GET_CODE (insn) == NOTE)
2793 insn = PREV_INSN (insn);
2794 return insn && GET_CODE (insn) != BARRIER;
2797 /* Emit code to alter this function's formal parms for a tail-recursive call.
2798 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
2799 FORMALS is the chain of decls of formals.
2800 Return 1 if this can be done;
2801 otherwise return 0 and do not emit any code. */
2804 tail_recursion_args (actuals, formals)
2805 tree actuals, formals;
2807 register tree a = actuals, f = formals;
2809 register rtx *argvec;
2811 /* Check that number and types of actuals are compatible
2812 with the formals. This is not always true in valid C code.
2813 Also check that no formal needs to be addressable
2814 and that all formals are scalars. */
2816 /* Also count the args. */
2818 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
2820 if (TREE_TYPE (TREE_VALUE (a)) != TREE_TYPE (f))
2822 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
2825 if (a != 0 || f != 0)
2828 /* Compute all the actuals. */
2830 argvec = (rtx *) alloca (i * sizeof (rtx));
2832 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2833 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
2835 /* Find which actual values refer to current values of previous formals.
2836 Copy each of them now, before any formal is changed. */
2838 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2842 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
2843 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
2844 { copy = 1; break; }
2846 argvec[i] = copy_to_reg (argvec[i]);
2849 /* Store the values of the actuals into the formals. */
2851 for (f = formals, a = actuals, i = 0; f;
2852 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
2854 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
2855 emit_move_insn (DECL_RTL (f), argvec[i]);
2857 convert_move (DECL_RTL (f), argvec[i],
2858 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
2865 /* Generate the RTL code for entering a binding contour.
2866 The variables are declared one by one, by calls to `expand_decl'.
2868 EXIT_FLAG is nonzero if this construct should be visible to
2869 `exit_something'. */
2872 expand_start_bindings (exit_flag)
2875 struct nesting *thisblock = ALLOC_NESTING ();
2876 rtx note = output_bytecode ? 0 : emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
2878 /* Make an entry on block_stack for the block we are entering. */
2880 thisblock->next = block_stack;
2881 thisblock->all = nesting_stack;
2882 thisblock->depth = ++nesting_depth;
2883 thisblock->data.block.stack_level = 0;
2884 thisblock->data.block.cleanups = 0;
2885 thisblock->data.block.function_call_count = 0;
2889 if (block_stack->data.block.cleanups == NULL_TREE
2890 && (block_stack->data.block.outer_cleanups == NULL_TREE
2891 || block_stack->data.block.outer_cleanups == empty_cleanup_list))
2892 thisblock->data.block.outer_cleanups = empty_cleanup_list;
2894 thisblock->data.block.outer_cleanups
2895 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2896 block_stack->data.block.outer_cleanups);
2899 thisblock->data.block.outer_cleanups = 0;
2903 && !(block_stack->data.block.cleanups == NULL_TREE
2904 && block_stack->data.block.outer_cleanups == NULL_TREE))
2905 thisblock->data.block.outer_cleanups
2906 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2907 block_stack->data.block.outer_cleanups);
2909 thisblock->data.block.outer_cleanups = 0;
2911 thisblock->data.block.label_chain = 0;
2912 thisblock->data.block.innermost_stack_block = stack_block_stack;
2913 thisblock->data.block.first_insn = note;
2914 thisblock->data.block.block_start_count = ++block_start_count;
2915 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
2916 block_stack = thisblock;
2917 nesting_stack = thisblock;
2919 if (!output_bytecode)
2921 /* Make a new level for allocating stack slots. */
2926 /* Given a pointer to a BLOCK node, save a pointer to the most recently
2927 generated NOTE_INSN_BLOCK_END in the BLOCK_END_NOTE field of the given
2931 remember_end_note (block)
2932 register tree block;
2934 BLOCK_END_NOTE (block) = last_block_end_note;
2935 last_block_end_note = NULL_RTX;
2938 /* Generate RTL code to terminate a binding contour.
2939 VARS is the chain of VAR_DECL nodes
2940 for the variables bound in this contour.
2941 MARK_ENDS is nonzero if we should put a note at the beginning
2942 and end of this binding contour.
2944 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
2945 (That is true automatically if the contour has a saved stack level.) */
2948 expand_end_bindings (vars, mark_ends, dont_jump_in)
2953 register struct nesting *thisblock = block_stack;
2956 if (output_bytecode)
2958 bc_expand_end_bindings (vars, mark_ends, dont_jump_in);
2963 for (decl = vars; decl; decl = TREE_CHAIN (decl))
2964 if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL
2965 && ! DECL_IN_SYSTEM_HEADER (decl))
2966 warning_with_decl (decl, "unused variable `%s'");
2968 if (thisblock->exit_label)
2970 do_pending_stack_adjust ();
2971 emit_label (thisblock->exit_label);
2974 /* If necessary, make a handler for nonlocal gotos taking
2975 place in the function calls in this block. */
2976 if (function_call_count != thisblock->data.block.function_call_count
2978 /* Make handler for outermost block
2979 if there were any nonlocal gotos to this function. */
2980 && (thisblock->next == 0 ? current_function_has_nonlocal_label
2981 /* Make handler for inner block if it has something
2982 special to do when you jump out of it. */
2983 : (thisblock->data.block.cleanups != 0
2984 || thisblock->data.block.stack_level != 0)))
2987 rtx afterward = gen_label_rtx ();
2988 rtx handler_label = gen_label_rtx ();
2989 rtx save_receiver = gen_reg_rtx (Pmode);
2992 /* Don't let jump_optimize delete the handler. */
2993 LABEL_PRESERVE_P (handler_label) = 1;
2995 /* Record the handler address in the stack slot for that purpose,
2996 during this block, saving and restoring the outer value. */
2997 if (thisblock->next != 0)
2999 emit_move_insn (nonlocal_goto_handler_slot, save_receiver);
3002 emit_move_insn (save_receiver, nonlocal_goto_handler_slot);
3003 insns = get_insns ();
3005 emit_insns_before (insns, thisblock->data.block.first_insn);
3009 emit_move_insn (nonlocal_goto_handler_slot,
3010 gen_rtx (LABEL_REF, Pmode, handler_label));
3011 insns = get_insns ();
3013 emit_insns_before (insns, thisblock->data.block.first_insn);
3015 /* Jump around the handler; it runs only when specially invoked. */
3016 emit_jump (afterward);
3017 emit_label (handler_label);
3019 #ifdef HAVE_nonlocal_goto
3020 if (! HAVE_nonlocal_goto)
3022 /* First adjust our frame pointer to its actual value. It was
3023 previously set to the start of the virtual area corresponding to
3024 the stacked variables when we branched here and now needs to be
3025 adjusted to the actual hardware fp value.
3027 Assignments are to virtual registers are converted by
3028 instantiate_virtual_regs into the corresponding assignment
3029 to the underlying register (fp in this case) that makes
3030 the original assignment true.
3031 So the following insn will actually be
3032 decrementing fp by STARTING_FRAME_OFFSET. */
3033 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3035 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3036 if (fixed_regs[ARG_POINTER_REGNUM])
3038 #ifdef ELIMINABLE_REGS
3039 /* If the argument pointer can be eliminated in favor of the
3040 frame pointer, we don't need to restore it. We assume here
3041 that if such an elimination is present, it can always be used.
3042 This is the case on all known machines; if we don't make this
3043 assumption, we do unnecessary saving on many machines. */
3044 static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
3047 for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
3048 if (elim_regs[i].from == ARG_POINTER_REGNUM
3049 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3052 if (i == sizeof elim_regs / sizeof elim_regs [0])
3055 /* Now restore our arg pointer from the address at which it
3056 was saved in our stack frame.
3057 If there hasn't be space allocated for it yet, make
3059 if (arg_pointer_save_area == 0)
3060 arg_pointer_save_area
3061 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
3062 emit_move_insn (virtual_incoming_args_rtx,
3063 /* We need a pseudo here, or else
3064 instantiate_virtual_regs_1 complains. */
3065 copy_to_reg (arg_pointer_save_area));
3070 /* The handler expects the desired label address in the static chain
3071 register. It tests the address and does an appropriate jump
3072 to whatever label is desired. */
3073 for (link = nonlocal_labels; link; link = TREE_CHAIN (link))
3074 /* Skip any labels we shouldn't be able to jump to from here. */
3075 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3077 rtx not_this = gen_label_rtx ();
3078 rtx this = gen_label_rtx ();
3079 do_jump_if_equal (static_chain_rtx,
3080 gen_rtx (LABEL_REF, Pmode, DECL_RTL (TREE_VALUE (link))),
3082 emit_jump (not_this);
3084 expand_goto (TREE_VALUE (link));
3085 emit_label (not_this);
3087 /* If label is not recognized, abort. */
3088 emit_library_call (gen_rtx (SYMBOL_REF, Pmode, "abort"), 0,
3090 emit_label (afterward);
3093 /* Don't allow jumping into a block that has cleanups or a stack level. */
3095 || thisblock->data.block.stack_level != 0
3096 || thisblock->data.block.cleanups != 0)
3098 struct label_chain *chain;
3100 /* Any labels in this block are no longer valid to go to.
3101 Mark them to cause an error message. */
3102 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3104 DECL_TOO_LATE (chain->label) = 1;
3105 /* If any goto without a fixup came to this label,
3106 that must be an error, because gotos without fixups
3107 come from outside all saved stack-levels and all cleanups. */
3108 if (TREE_ADDRESSABLE (chain->label))
3109 error_with_decl (chain->label,
3110 "label `%s' used before containing binding contour");
3114 /* Restore stack level in effect before the block
3115 (only if variable-size objects allocated). */
3116 /* Perform any cleanups associated with the block. */
3118 if (thisblock->data.block.stack_level != 0
3119 || thisblock->data.block.cleanups != 0)
3121 /* Only clean up here if this point can actually be reached. */
3122 int reachable = GET_CODE (get_last_insn ()) != BARRIER;
3124 /* Don't let cleanups affect ({...}) constructs. */
3125 int old_expr_stmts_for_value = expr_stmts_for_value;
3126 rtx old_last_expr_value = last_expr_value;
3127 tree old_last_expr_type = last_expr_type;
3128 expr_stmts_for_value = 0;
3130 /* Do the cleanups. */
3131 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3133 do_pending_stack_adjust ();
3135 expr_stmts_for_value = old_expr_stmts_for_value;
3136 last_expr_value = old_last_expr_value;
3137 last_expr_type = old_last_expr_type;
3139 /* Restore the stack level. */
3141 if (reachable && thisblock->data.block.stack_level != 0)
3143 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3144 thisblock->data.block.stack_level, NULL_RTX);
3145 if (nonlocal_goto_handler_slot != 0)
3146 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3150 /* Any gotos out of this block must also do these things.
3151 Also report any gotos with fixups that came to labels in this
3153 fixup_gotos (thisblock,
3154 thisblock->data.block.stack_level,
3155 thisblock->data.block.cleanups,
3156 thisblock->data.block.first_insn,
3160 /* Mark the beginning and end of the scope if requested.
3161 We do this now, after running cleanups on the variables
3162 just going out of scope, so they are in scope for their cleanups. */
3165 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
3167 /* Get rid of the beginning-mark if we don't make an end-mark. */
3168 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3170 /* If doing stupid register allocation, make sure lives of all
3171 register variables declared here extend thru end of scope. */
3174 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3176 rtx rtl = DECL_RTL (decl);
3177 if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
3181 /* Restore block_stack level for containing block. */
3183 stack_block_stack = thisblock->data.block.innermost_stack_block;
3184 POPSTACK (block_stack);
3186 /* Pop the stack slot nesting and free any slots at this level. */
3191 /* End a binding contour.
3192 VARS is the chain of VAR_DECL nodes for the variables bound
3193 in this contour. MARK_ENDS is nonzer if we should put a note
3194 at the beginning and end of this binding contour.
3195 DONT_JUMP_IN is nonzero if it is not valid to jump into this
3199 bc_expand_end_bindings (vars, mark_ends, dont_jump_in)
3204 struct nesting *thisbind = nesting_stack;
3208 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3209 if (! TREE_USED (TREE_VALUE (decl)) && TREE_CODE (TREE_VALUE (decl)) == VAR_DECL)
3210 warning_with_decl (decl, "unused variable `%s'");
3212 if (thisbind->exit_label)
3213 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisbind->exit_label));
3215 /* Pop block/bindings off stack */
3216 POPSTACK (block_stack);
3219 /* Generate RTL for the automatic variable declaration DECL.
3220 (Other kinds of declarations are simply ignored if seen here.)
3221 CLEANUP is an expression to be executed at exit from this binding contour;
3222 for example, in C++, it might call the destructor for this variable.
3224 If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
3225 either before or after calling `expand_decl' but before compiling
3226 any subsequent expressions. This is because CLEANUP may be expanded
3227 more than once, on different branches of execution.
3228 For the same reason, CLEANUP may not contain a CALL_EXPR
3229 except as its topmost node--else `preexpand_calls' would get confused.
3231 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3232 that is not associated with any particular variable.
3234 There is no special support here for C++ constructors.
3235 They should be handled by the proper code in DECL_INITIAL. */
3241 struct nesting *thisblock = block_stack;
3244 if (output_bytecode)
3246 bc_expand_decl (decl, 0);
3250 type = TREE_TYPE (decl);
3252 /* Only automatic variables need any expansion done.
3253 Static and external variables, and external functions,
3254 will be handled by `assemble_variable' (called from finish_decl).
3255 TYPE_DECL and CONST_DECL require nothing.
3256 PARM_DECLs are handled in `assign_parms'. */
3258 if (TREE_CODE (decl) != VAR_DECL)
3260 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3263 /* Create the RTL representation for the variable. */
3265 if (type == error_mark_node)
3266 DECL_RTL (decl) = gen_rtx (MEM, BLKmode, const0_rtx);
3267 else if (DECL_SIZE (decl) == 0)
3268 /* Variable with incomplete type. */
3270 if (DECL_INITIAL (decl) == 0)
3271 /* Error message was already done; now avoid a crash. */
3272 DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
3274 /* An initializer is going to decide the size of this array.
3275 Until we know the size, represent its address with a reg. */
3276 DECL_RTL (decl) = gen_rtx (MEM, BLKmode, gen_reg_rtx (Pmode));
3277 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (type);
3279 else if (DECL_MODE (decl) != BLKmode
3280 /* If -ffloat-store, don't put explicit float vars
3282 && !(flag_float_store
3283 && TREE_CODE (type) == REAL_TYPE)
3284 && ! TREE_THIS_VOLATILE (decl)
3285 && ! TREE_ADDRESSABLE (decl)
3286 && (DECL_REGISTER (decl) || ! obey_regdecls))
3288 /* Automatic variable that can go in a register. */
3289 int unsignedp = TREE_UNSIGNED (type);
3290 enum machine_mode reg_mode
3291 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3293 if (TREE_CODE (type) == COMPLEX_TYPE)
3295 rtx realpart, imagpart;
3296 enum machine_mode partmode = TYPE_MODE (TREE_TYPE (type));
3298 /* For a complex type variable, make a CONCAT of two pseudos
3299 so that the real and imaginary parts
3300 can be allocated separately. */
3301 realpart = gen_reg_rtx (partmode);
3302 REG_USERVAR_P (realpart) = 1;
3303 imagpart = gen_reg_rtx (partmode);
3304 REG_USERVAR_P (imagpart) = 1;
3305 DECL_RTL (decl) = gen_rtx (CONCAT, reg_mode, realpart, imagpart);
3309 DECL_RTL (decl) = gen_reg_rtx (reg_mode);
3310 if (TREE_CODE (type) == POINTER_TYPE)
3311 mark_reg_pointer (DECL_RTL (decl));
3312 REG_USERVAR_P (DECL_RTL (decl)) = 1;
3315 else if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST)
3317 /* Variable of fixed size that goes on the stack. */
3321 /* If we previously made RTL for this decl, it must be an array
3322 whose size was determined by the initializer.
3323 The old address was a register; set that register now
3324 to the proper address. */
3325 if (DECL_RTL (decl) != 0)
3327 if (GET_CODE (DECL_RTL (decl)) != MEM
3328 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3330 oldaddr = XEXP (DECL_RTL (decl), 0);
3334 = assign_stack_temp (DECL_MODE (decl),
3335 ((TREE_INT_CST_LOW (DECL_SIZE (decl))
3336 + BITS_PER_UNIT - 1)
3339 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (TREE_TYPE (decl));
3341 /* Set alignment we actually gave this decl. */
3342 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3343 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3347 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3348 if (addr != oldaddr)
3349 emit_move_insn (oldaddr, addr);
3352 /* If this is a memory ref that contains aggregate components,
3353 mark it as such for cse and loop optimize. */
3354 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (TREE_TYPE (decl));
3356 /* If this is in memory because of -ffloat-store,
3357 set the volatile bit, to prevent optimizations from
3358 undoing the effects. */
3359 if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
3360 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3364 /* Dynamic-size object: must push space on the stack. */
3368 /* Record the stack pointer on entry to block, if have
3369 not already done so. */
3370 if (thisblock->data.block.stack_level == 0)
3372 do_pending_stack_adjust ();
3373 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3374 &thisblock->data.block.stack_level,
3375 thisblock->data.block.first_insn);
3376 stack_block_stack = thisblock;
3379 /* Compute the variable's size, in bytes. */
3380 size = expand_expr (size_binop (CEIL_DIV_EXPR,
3382 size_int (BITS_PER_UNIT)),
3383 NULL_RTX, VOIDmode, 0);
3386 /* Allocate space on the stack for the variable. */
3387 address = allocate_dynamic_stack_space (size, NULL_RTX,
3390 /* Reference the variable indirect through that rtx. */
3391 DECL_RTL (decl) = gen_rtx (MEM, DECL_MODE (decl), address);
3393 /* If this is a memory ref that contains aggregate components,
3394 mark it as such for cse and loop optimize. */
3395 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (TREE_TYPE (decl));
3397 /* Indicate the alignment we actually gave this variable. */
3398 #ifdef STACK_BOUNDARY
3399 DECL_ALIGN (decl) = STACK_BOUNDARY;
3401 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3405 if (TREE_THIS_VOLATILE (decl))
3406 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3407 #if 0 /* A variable is not necessarily unchanging
3408 just because it is const. RTX_UNCHANGING_P
3409 means no change in the function,
3410 not merely no change in the variable's scope.
3411 It is correct to set RTX_UNCHANGING_P if the variable's scope
3412 is the whole function. There's no convenient way to test that. */
3413 if (TREE_READONLY (decl))
3414 RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
3417 /* If doing stupid register allocation, make sure life of any
3418 register variable starts here, at the start of its scope. */
3421 use_variable (DECL_RTL (decl));
3425 /* Generate code for the automatic variable declaration DECL. For
3426 most variables this just means we give it a stack offset. The
3427 compiler sometimes emits cleanups without variables and we will
3428 have to deal with those too. */
3431 bc_expand_decl (decl, cleanup)
3439 /* A cleanup with no variable. */
3446 /* Only auto variables need any work. */
3447 if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3450 type = TREE_TYPE (decl);
3452 if (type == error_mark_node)
3453 DECL_RTL (decl) = bc_gen_rtx ((char *) 0, 0, (struct bc_label *) 0);
3455 else if (DECL_SIZE (decl) == 0)
3457 /* Variable with incomplete type. The stack offset herein will be
3458 fixed later in expand_decl_init (). */
3459 DECL_RTL (decl) = bc_gen_rtx ((char *) 0, 0, (struct bc_label *) 0);
3461 else if (TREE_CONSTANT (DECL_SIZE (decl)))
3463 DECL_RTL (decl) = bc_allocate_local (TREE_INT_CST_LOW (DECL_SIZE (decl)) / BITS_PER_UNIT,
3467 DECL_RTL (decl) = bc_allocate_variable_array (DECL_SIZE (decl));
3470 /* Emit code to perform the initialization of a declaration DECL. */
3473 expand_decl_init (decl)
3476 int was_used = TREE_USED (decl);
3478 if (output_bytecode)
3480 bc_expand_decl_init (decl);
3484 /* If this is a CONST_DECL, we don't have to generate any code, but
3485 if DECL_INITIAL is a constant, call expand_expr to force TREE_CST_RTL
3486 to be set while in the obstack containing the constant. If we don't
3487 do this, we can lose if we have functions nested three deep and the middle
3488 function makes a CONST_DECL whose DECL_INITIAL is a STRING_CST while
3489 the innermost function is the first to expand that STRING_CST. */
3490 if (TREE_CODE (decl) == CONST_DECL)
3492 if (DECL_INITIAL (decl) && TREE_CONSTANT (DECL_INITIAL (decl)))
3493 expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
3494 EXPAND_INITIALIZER);
3498 if (TREE_STATIC (decl))
3501 /* Compute and store the initial value now. */
3503 if (DECL_INITIAL (decl) == error_mark_node)
3505 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3506 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3507 || code == POINTER_TYPE)
3508 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3512 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3514 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
3515 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
3519 /* Don't let the initialization count as "using" the variable. */
3520 TREE_USED (decl) = was_used;
3522 /* Free any temporaries we made while initializing the decl. */
3526 /* Expand initialization for variable-sized types. Allocate array
3527 using newlocalSI and set local variable, which is a pointer to the
3531 bc_expand_variable_local_init (decl)
3534 /* Evaluate size expression and coerce to SI */
3535 bc_expand_expr (DECL_SIZE (decl));
3537 /* Type sizes are always (?) of TREE_CODE INTEGER_CST, so
3538 no coercion is necessary (?) */
3540 /* emit_typecode_conversion (preferred_typecode (TYPE_MODE (DECL_SIZE (decl)),
3541 TREE_UNSIGNED (DECL_SIZE (decl))), SIcode); */
3543 /* Emit code to allocate array */
3544 bc_emit_instruction (newlocalSI);
3546 /* Store array pointer in local variable. This is the only instance
3547 where we actually want the address of the pointer to the
3548 variable-size block, rather than the pointer itself. We avoid
3549 using expand_address() since that would cause the pointer to be
3550 pushed rather than its address. Hence the hard-coded reference;
3551 notice also that the variable is always local (no global
3552 variable-size type variables). */
3554 bc_load_localaddr (DECL_RTL (decl));
3555 bc_emit_instruction (storeP);
3559 /* Emit code to initialize a declaration. */
3562 bc_expand_decl_init (decl)
3565 int org_stack_depth;
3567 /* Statical initializers are handled elsewhere */
3569 if (TREE_STATIC (decl))
3572 /* Memory original stack depth */
3573 org_stack_depth = stack_depth;
3575 /* If the type is variable-size, we first create its space (we ASSUME
3576 it CAN'T be static). We do this regardless of whether there's an
3577 initializer assignment or not. */
3579 if (TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
3580 bc_expand_variable_local_init (decl);
3582 /* Expand initializer assignment */
3583 if (DECL_INITIAL (decl) == error_mark_node)
3585 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3587 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3588 || code == POINTER_TYPE)
3590 expand_assignment (TREE_TYPE (decl), decl, 0, 0);
3592 else if (DECL_INITIAL (decl))
3593 expand_assignment (TREE_TYPE (decl), decl, 0, 0);
3595 /* Restore stack depth */
3596 if (org_stack_depth > stack_depth)
3599 bc_adjust_stack (stack_depth - org_stack_depth);
3603 /* CLEANUP is an expression to be executed at exit from this binding contour;
3604 for example, in C++, it might call the destructor for this variable.
3606 If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
3607 either before or after calling `expand_decl' but before compiling
3608 any subsequent expressions. This is because CLEANUP may be expanded
3609 more than once, on different branches of execution.
3610 For the same reason, CLEANUP may not contain a CALL_EXPR
3611 except as its topmost node--else `preexpand_calls' would get confused.
3613 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3614 that is not associated with any particular variable. */
3617 expand_decl_cleanup (decl, cleanup)
3620 struct nesting *thisblock = block_stack;
3622 /* Error if we are not in any block. */
3626 /* Record the cleanup if there is one. */
3630 thisblock->data.block.cleanups
3631 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3632 /* If this block has a cleanup, it belongs in stack_block_stack. */
3633 stack_block_stack = thisblock;
3634 (*interim_eh_hook) (NULL_TREE);
3639 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3640 DECL_ELTS is the list of elements that belong to DECL's type.
3641 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3644 expand_anon_union_decl (decl, cleanup, decl_elts)
3645 tree decl, cleanup, decl_elts;
3647 struct nesting *thisblock = block_stack;
3650 expand_decl (decl, cleanup);
3651 x = DECL_RTL (decl);
3655 tree decl_elt = TREE_VALUE (decl_elts);
3656 tree cleanup_elt = TREE_PURPOSE (decl_elts);
3657 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3659 /* Propagate the union's alignment to the elements. */
3660 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
3662 /* If the element has BLKmode and the union doesn't, the union is
3663 aligned such that the element doesn't need to have BLKmode, so
3664 change the element's mode to the appropriate one for its size. */
3665 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
3666 DECL_MODE (decl_elt) = mode
3667 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl_elt)),
3670 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3671 instead create a new MEM rtx with the proper mode. */
3672 if (GET_CODE (x) == MEM)
3674 if (mode == GET_MODE (x))
3675 DECL_RTL (decl_elt) = x;
3678 DECL_RTL (decl_elt) = gen_rtx (MEM, mode, copy_rtx (XEXP (x, 0)));
3679 MEM_IN_STRUCT_P (DECL_RTL (decl_elt)) = MEM_IN_STRUCT_P (x);
3680 RTX_UNCHANGING_P (DECL_RTL (decl_elt)) = RTX_UNCHANGING_P (x);
3683 else if (GET_CODE (x) == REG)
3685 if (mode == GET_MODE (x))
3686 DECL_RTL (decl_elt) = x;
3688 DECL_RTL (decl_elt) = gen_rtx (SUBREG, mode, x, 0);
3693 /* Record the cleanup if there is one. */
3696 thisblock->data.block.cleanups
3697 = temp_tree_cons (decl_elt, cleanup_elt,
3698 thisblock->data.block.cleanups);
3700 decl_elts = TREE_CHAIN (decl_elts);
3704 /* Expand a list of cleanups LIST.
3705 Elements may be expressions or may be nested lists.
3707 If DONT_DO is nonnull, then any list-element
3708 whose TREE_PURPOSE matches DONT_DO is omitted.
3709 This is sometimes used to avoid a cleanup associated with
3710 a value that is being returned out of the scope.
3712 If IN_FIXUP is non-zero, we are generating this cleanup for a fixup
3713 goto and handle protection regions specially in that case.
3715 If REACHABLE, we emit code, otherwise just inform the exception handling
3716 code about this finalization. */
3719 expand_cleanups (list, dont_do, in_fixup, reachable)
3726 for (tail = list; tail; tail = TREE_CHAIN (tail))
3727 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
3729 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
3730 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
3734 (*interim_eh_hook) (TREE_VALUE (tail));
3738 /* Cleanups may be run multiple times. For example,
3739 when exiting a binding contour, we expand the
3740 cleanups associated with that contour. When a goto
3741 within that binding contour has a target outside that
3742 contour, it will expand all cleanups from its scope to
3743 the target. Though the cleanups are expanded multiple
3744 times, the control paths are non-overlapping so the
3745 cleanups will not be executed twice. */
3746 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3753 /* Move all cleanups from the current block_stack
3754 to the containing block_stack, where they are assumed to
3755 have been created. If anything can cause a temporary to
3756 be created, but not expanded for more than one level of
3757 block_stacks, then this code will have to change. */
3762 struct nesting *block = block_stack;
3763 struct nesting *outer = block->next;
3765 outer->data.block.cleanups
3766 = chainon (block->data.block.cleanups,
3767 outer->data.block.cleanups);
3768 block->data.block.cleanups = 0;
3772 last_cleanup_this_contour ()
3774 if (block_stack == 0)
3777 return block_stack->data.block.cleanups;
3780 /* Return 1 if there are any pending cleanups at this point.
3781 If THIS_CONTOUR is nonzero, check the current contour as well.
3782 Otherwise, look only at the contours that enclose this one. */
3785 any_pending_cleanups (this_contour)
3788 struct nesting *block;
3790 if (block_stack == 0)
3793 if (this_contour && block_stack->data.block.cleanups != NULL)
3795 if (block_stack->data.block.cleanups == 0
3796 && (block_stack->data.block.outer_cleanups == 0
3798 || block_stack->data.block.outer_cleanups == empty_cleanup_list
3803 for (block = block_stack->next; block; block = block->next)
3804 if (block->data.block.cleanups != 0)
3810 /* Enter a case (Pascal) or switch (C) statement.
3811 Push a block onto case_stack and nesting_stack
3812 to accumulate the case-labels that are seen
3813 and to record the labels generated for the statement.
3815 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
3816 Otherwise, this construct is transparent for `exit_something'.
3818 EXPR is the index-expression to be dispatched on.
3819 TYPE is its nominal type. We could simply convert EXPR to this type,
3820 but instead we take short cuts. */
3823 expand_start_case (exit_flag, expr, type, printname)
3829 register struct nesting *thiscase = ALLOC_NESTING ();
3831 /* Make an entry on case_stack for the case we are entering. */
3833 thiscase->next = case_stack;
3834 thiscase->all = nesting_stack;
3835 thiscase->depth = ++nesting_depth;
3836 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
3837 thiscase->data.case_stmt.case_list = 0;
3838 thiscase->data.case_stmt.index_expr = expr;
3839 thiscase->data.case_stmt.nominal_type = type;
3840 thiscase->data.case_stmt.default_label = 0;
3841 thiscase->data.case_stmt.num_ranges = 0;
3842 thiscase->data.case_stmt.printname = printname;
3843 thiscase->data.case_stmt.seenlabel = 0;
3844 case_stack = thiscase;
3845 nesting_stack = thiscase;
3847 if (output_bytecode)
3849 bc_expand_start_case (thiscase, expr, type, printname);
3853 do_pending_stack_adjust ();
3855 /* Make sure case_stmt.start points to something that won't
3856 need any transformation before expand_end_case. */
3857 if (GET_CODE (get_last_insn ()) != NOTE)
3858 emit_note (NULL_PTR, NOTE_INSN_DELETED);
3860 thiscase->data.case_stmt.start = get_last_insn ();
3864 /* Enter a case statement. It is assumed that the caller has pushed
3865 the current context onto the case stack. */
3868 bc_expand_start_case (thiscase, expr, type, printname)
3869 struct nesting *thiscase;
3874 bc_expand_expr (expr);
3875 bc_expand_conversion (TREE_TYPE (expr), type);
3877 /* For cases, the skip is a place we jump to that's emitted after
3878 the size of the jump table is known. */
3880 thiscase->data.case_stmt.skip_label = gen_label_rtx ();
3881 bc_emit_bytecode (jump);
3882 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->data.case_stmt.skip_label));
3884 #ifdef DEBUG_PRINT_CODE
3885 fputc ('\n', stderr);
3890 /* Start a "dummy case statement" within which case labels are invalid
3891 and are not connected to any larger real case statement.
3892 This can be used if you don't want to let a case statement jump
3893 into the middle of certain kinds of constructs. */
3896 expand_start_case_dummy ()
3898 register struct nesting *thiscase = ALLOC_NESTING ();
3900 /* Make an entry on case_stack for the dummy. */
3902 thiscase->next = case_stack;
3903 thiscase->all = nesting_stack;
3904 thiscase->depth = ++nesting_depth;
3905 thiscase->exit_label = 0;
3906 thiscase->data.case_stmt.case_list = 0;
3907 thiscase->data.case_stmt.start = 0;
3908 thiscase->data.case_stmt.nominal_type = 0;
3909 thiscase->data.case_stmt.default_label = 0;
3910 thiscase->data.case_stmt.num_ranges = 0;
3911 case_stack = thiscase;
3912 nesting_stack = thiscase;
3915 /* End a dummy case statement. */
3918 expand_end_case_dummy ()
3920 POPSTACK (case_stack);
3923 /* Return the data type of the index-expression
3924 of the innermost case statement, or null if none. */
3927 case_index_expr_type ()
3930 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
3934 /* Accumulate one case or default label inside a case or switch statement.
3935 VALUE is the value of the case (a null pointer, for a default label).
3936 The function CONVERTER, when applied to arguments T and V,
3937 converts the value V to the type T.
3939 If not currently inside a case or switch statement, return 1 and do
3940 nothing. The caller will print a language-specific error message.
3941 If VALUE is a duplicate or overlaps, return 2 and do nothing
3942 except store the (first) duplicate node in *DUPLICATE.
3943 If VALUE is out of range, return 3 and do nothing.
3944 If we are jumping into the scope of a cleaup or var-sized array, return 5.
3945 Return 0 on success.
3947 Extended to handle range statements. */
3950 pushcase (value, converter, label, duplicate)
3951 register tree value;
3952 tree (*converter) PROTO((tree, tree));
3953 register tree label;
3956 register struct case_node **l;
3957 register struct case_node *n;
3961 if (output_bytecode)
3962 return bc_pushcase (value, label);
3964 /* Fail if not inside a real case statement. */
3965 if (! (case_stack && case_stack->data.case_stmt.start))
3968 if (stack_block_stack
3969 && stack_block_stack->depth > case_stack->depth)
3972 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3973 nominal_type = case_stack->data.case_stmt.nominal_type;
3975 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3976 if (index_type == error_mark_node)
3979 /* Convert VALUE to the type in which the comparisons are nominally done. */
3981 value = (*converter) (nominal_type, value);
3983 /* If this is the first label, warn if any insns have been emitted. */
3984 if (case_stack->data.case_stmt.seenlabel == 0)
3987 for (insn = case_stack->data.case_stmt.start;
3989 insn = NEXT_INSN (insn))
3991 if (GET_CODE (insn) == CODE_LABEL)
3993 if (GET_CODE (insn) != NOTE
3994 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
3996 warning ("unreachable code at beginning of %s",
3997 case_stack->data.case_stmt.printname);
4002 case_stack->data.case_stmt.seenlabel = 1;
4004 /* Fail if this value is out of range for the actual type of the index
4005 (which may be narrower than NOMINAL_TYPE). */
4006 if (value != 0 && ! int_fits_type_p (value, index_type))
4009 /* Fail if this is a duplicate or overlaps another entry. */
4012 if (case_stack->data.case_stmt.default_label != 0)
4014 *duplicate = case_stack->data.case_stmt.default_label;
4017 case_stack->data.case_stmt.default_label = label;
4021 /* Find the elt in the chain before which to insert the new value,
4022 to keep the chain sorted in increasing order.
4023 But report an error if this element is a duplicate. */
4024 for (l = &case_stack->data.case_stmt.case_list;
4025 /* Keep going past elements distinctly less than VALUE. */
4026 *l != 0 && tree_int_cst_lt ((*l)->high, value);
4031 /* Element we will insert before must be distinctly greater;
4032 overlap means error. */
4033 if (! tree_int_cst_lt (value, (*l)->low))
4035 *duplicate = (*l)->code_label;
4040 /* Add this label to the chain, and succeed.
4041 Copy VALUE so it is on temporary rather than momentary
4042 obstack and will thus survive till the end of the case statement. */
4043 n = (struct case_node *) oballoc (sizeof (struct case_node));
4046 n->high = n->low = copy_node (value);
4047 n->code_label = label;
4051 expand_label (label);
4055 /* Like pushcase but this case applies to all values
4056 between VALUE1 and VALUE2 (inclusive).
4057 The return value is the same as that of pushcase
4058 but there is one additional error code:
4059 4 means the specified range was empty. */
4062 pushcase_range (value1, value2, converter, label, duplicate)
4063 register tree value1, value2;
4064 tree (*converter) PROTO((tree, tree));
4065 register tree label;
4068 register struct case_node **l;
4069 register struct case_node *n;
4073 /* Fail if not inside a real case statement. */
4074 if (! (case_stack && case_stack->data.case_stmt.start))
4077 if (stack_block_stack
4078 && stack_block_stack->depth > case_stack->depth)
4081 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4082 nominal_type = case_stack->data.case_stmt.nominal_type;
4084 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4085 if (index_type == error_mark_node)
4088 /* If this is the first label, warn if any insns have been emitted. */
4089 if (case_stack->data.case_stmt.seenlabel == 0)
4092 for (insn = case_stack->data.case_stmt.start;
4094 insn = NEXT_INSN (insn))
4096 if (GET_CODE (insn) == CODE_LABEL)
4098 if (GET_CODE (insn) != NOTE
4099 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4101 warning ("unreachable code at beginning of %s",
4102 case_stack->data.case_stmt.printname);
4107 case_stack->data.case_stmt.seenlabel = 1;
4109 /* Convert VALUEs to type in which the comparisons are nominally done. */
4110 if (value1 == 0) /* Negative infinity. */
4111 value1 = TYPE_MIN_VALUE(index_type);
4112 value1 = (*converter) (nominal_type, value1);
4114 if (value2 == 0) /* Positive infinity. */
4115 value2 = TYPE_MAX_VALUE(index_type);
4116 value2 = (*converter) (nominal_type, value2);
4118 /* Fail if these values are out of range. */
4119 if (! int_fits_type_p (value1, index_type))
4122 if (! int_fits_type_p (value2, index_type))
4125 /* Fail if the range is empty. */
4126 if (tree_int_cst_lt (value2, value1))
4129 /* If the bounds are equal, turn this into the one-value case. */
4130 if (tree_int_cst_equal (value1, value2))
4131 return pushcase (value1, converter, label, duplicate);
4133 /* Find the elt in the chain before which to insert the new value,
4134 to keep the chain sorted in increasing order.
4135 But report an error if this element is a duplicate. */
4136 for (l = &case_stack->data.case_stmt.case_list;
4137 /* Keep going past elements distinctly less than this range. */
4138 *l != 0 && tree_int_cst_lt ((*l)->high, value1);
4143 /* Element we will insert before must be distinctly greater;
4144 overlap means error. */
4145 if (! tree_int_cst_lt (value2, (*l)->low))
4147 *duplicate = (*l)->code_label;
4152 /* Add this label to the chain, and succeed.
4153 Copy VALUE1, VALUE2 so they are on temporary rather than momentary
4154 obstack and will thus survive till the end of the case statement. */
4156 n = (struct case_node *) oballoc (sizeof (struct case_node));
4159 n->low = copy_node (value1);
4160 n->high = copy_node (value2);
4161 n->code_label = label;
4164 expand_label (label);
4166 case_stack->data.case_stmt.num_ranges++;
4172 /* Accumulate one case or default label; VALUE is the value of the
4173 case, or nil for a default label. If not currently inside a case,
4174 return 1 and do nothing. If VALUE is a duplicate or overlaps, return
4175 2 and do nothing. If VALUE is out of range, return 3 and do nothing.
4176 Return 0 on success. This function is a leftover from the earlier
4177 bytecode compiler, which was based on gcc 1.37. It should be
4178 merged into pushcase. */
4181 bc_pushcase (value, label)
4185 struct nesting *thiscase = case_stack;
4186 struct case_node *case_label, *new_label;
4191 /* Fail if duplicate, overlap, or out of type range. */
4194 value = convert (thiscase->data.case_stmt.nominal_type, value);
4195 if (! int_fits_type_p (value, thiscase->data.case_stmt.nominal_type))
4198 for (case_label = thiscase->data.case_stmt.case_list;
4199 case_label->left; case_label = case_label->left)
4200 if (! tree_int_cst_lt (case_label->left->high, value))
4203 if (case_label != thiscase->data.case_stmt.case_list
4204 && ! tree_int_cst_lt (case_label->high, value)
4205 || case_label->left && ! tree_int_cst_lt (value, case_label->left->low))
4208 new_label = (struct case_node *) oballoc (sizeof (struct case_node));
4209 new_label->low = new_label->high = copy_node (value);
4210 new_label->code_label = label;
4211 new_label->left = case_label->left;
4213 case_label->left = new_label;
4214 thiscase->data.case_stmt.num_ranges++;
4218 if (thiscase->data.case_stmt.default_label)
4220 thiscase->data.case_stmt.default_label = label;
4223 expand_label (label);
4227 /* Returns the number of possible values of TYPE.
4228 Returns -1 if the number is unknown or variable.
4229 Returns -2 if the number does not fit in a HOST_WIDE_INT.
4230 Sets *SPARENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4231 do not increase monotonically (there may be duplicates);
4232 to 1 if the values increase monotonically, but not always by 1;
4233 otherwise sets it to 0. */
4236 all_cases_count (type, spareness)
4240 HOST_WIDE_INT count, count_high = 0;
4243 switch (TREE_CODE (type))
4250 count = 1 << BITS_PER_UNIT;
4254 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4255 || TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST)
4260 = TREE_INT_CST_LOW (TYPE_MAX_VALUE (type))
4261 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + 1
4262 but with overflow checking. */
4263 tree mint = TYPE_MIN_VALUE (type);
4264 tree maxt = TYPE_MAX_VALUE (type);
4265 HOST_WIDE_INT lo, hi;
4266 neg_double(TREE_INT_CST_LOW (mint), TREE_INT_CST_HIGH (mint),
4268 add_double(TREE_INT_CST_LOW (maxt), TREE_INT_CST_HIGH (maxt),
4270 add_double (lo, hi, 1, 0, &lo, &hi);
4271 if (hi != 0 || lo < 0)
4278 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4280 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4281 || TREE_CODE (TREE_VALUE (t)) != INTEGER_CST
4282 || TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + count
4283 != TREE_INT_CST_LOW (TREE_VALUE (t)))
4287 if (*spareness == 1)
4289 tree prev = TREE_VALUE (TYPE_VALUES (type));
4290 for (t = TYPE_VALUES (type); t = TREE_CHAIN (t), t != NULL_TREE; )
4292 if (! tree_int_cst_lt (prev, TREE_VALUE (t)))
4297 prev = TREE_VALUE (t);
4306 #define BITARRAY_TEST(ARRAY, INDEX) \
4307 ((ARRAY)[(unsigned)(INDEX) / HOST_BITS_PER_CHAR]\
4308 & (1 << ((unsigned)(INDEX) % HOST_BITS_PER_CHAR)))
4309 #define BITARRAY_SET(ARRAY, INDEX) \
4310 ((ARRAY)[(unsigned)(INDEX) / HOST_BITS_PER_CHAR]\
4311 |= 1 << ((unsigned)(INDEX) % HOST_BITS_PER_CHAR))
4313 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4314 with the case values we have seen, assuming the case expression
4316 SPARSENESS is as determined by all_cases_count.
4318 The time needed is propotional to COUNT, unless
4319 SPARSENESS is 2, in which case quadratic time is needed. */
4322 mark_seen_cases (type, cases_seen, count, sparseness)
4324 unsigned char *cases_seen;
4330 tree next_node_to_try = NULL_TREE;
4331 long next_node_offset = 0;
4333 register struct case_node *n;
4334 tree val = make_node (INTEGER_CST);
4335 TREE_TYPE (val) = type;
4336 for (n = case_stack->data.case_stmt.case_list; n;
4339 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4340 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4341 while ( ! tree_int_cst_lt (n->high, val))
4343 /* Calculate (into xlo) the "offset" of the integer (val).
4344 The element with lowest value has offset 0, the next smallest
4345 element has offset 1, etc. */
4347 HOST_WIDE_INT xlo, xhi;
4349 if (sparseness == 2)
4351 /* This less efficient loop is only needed to handle
4352 duplicate case values (multiple enum constants
4353 with the same value). */
4354 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4355 t = TREE_CHAIN (t), xlo++)
4357 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4358 BITARRAY_SET (cases_seen, xlo);
4363 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4365 /* The TYPE_VALUES will be in increasing order, so
4366 starting searching where we last ended. */
4367 t = next_node_to_try;
4368 xlo = next_node_offset;
4374 t = TYPE_VALUES (type);
4377 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4379 next_node_to_try = TREE_CHAIN (t);
4380 next_node_offset = xlo + 1;
4385 if (t == next_node_to_try)
4391 t = TYPE_MIN_VALUE (type);
4393 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
4397 add_double (xlo, xhi,
4398 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4402 if (xhi == 0 && xlo >= 0 && xlo < count)
4403 BITARRAY_SET (cases_seen, xlo);
4405 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4407 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
4412 /* Called when the index of a switch statement is an enumerated type
4413 and there is no default label.
4415 Checks that all enumeration literals are covered by the case
4416 expressions of a switch. Also, warn if there are any extra
4417 switch cases that are *not* elements of the enumerated type.
4419 If all enumeration literals were covered by the case expressions,
4420 turn one of the expressions into the default expression since it should
4421 not be possible to fall through such a switch. */
4424 check_for_full_enumeration_handling (type)
4427 register struct case_node *n;
4428 register struct case_node **l;
4429 register tree chain;
4432 /* True iff the selector type is a numbered set mode. */
4435 /* The number of possible selector values. */
4438 /* For each possible selector value. a one iff it has been matched
4439 by a case value alternative. */
4440 unsigned char *cases_seen;
4442 /* The allocated size of cases_seen, in chars. */
4446 if (output_bytecode)
4448 bc_check_for_full_enumeration_handling (type);
4455 size = all_cases_count (type, &sparseness);
4456 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
4458 if (size > 0 && size < 600000
4459 /* We deliberately use malloc here - not xmalloc. */
4460 && (cases_seen = (unsigned char *) malloc (bytes_needed)) != NULL)
4463 tree v = TYPE_VALUES (type);
4464 bzero (cases_seen, bytes_needed);
4466 /* The time complexity of this code is normally O(N), where
4467 N being the number of members in the enumerated type.
4468 However, if type is a ENUMERAL_TYPE whose values do not
4469 increase monotonically, quadratic time may be needed. */
4471 mark_seen_cases (type, cases_seen, size, sparseness);
4473 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
4475 if (BITARRAY_TEST(cases_seen, i) == 0)
4476 warning ("enumeration value `%s' not handled in switch",
4477 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
4483 /* Now we go the other way around; we warn if there are case
4484 expressions that don't correspond to enumerators. This can
4485 occur since C and C++ don't enforce type-checking of
4486 assignments to enumeration variables. */
4489 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
4491 for (chain = TYPE_VALUES (type);
4492 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
4493 chain = TREE_CHAIN (chain))
4498 if (TYPE_NAME (type) == 0)
4499 warning ("case value `%d' not in enumerated type",
4500 TREE_INT_CST_LOW (n->low));
4502 warning ("case value `%d' not in enumerated type `%s'",
4503 TREE_INT_CST_LOW (n->low),
4504 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4507 : DECL_NAME (TYPE_NAME (type))));
4509 if (!tree_int_cst_equal (n->low, n->high))
4511 for (chain = TYPE_VALUES (type);
4512 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
4513 chain = TREE_CHAIN (chain))
4518 if (TYPE_NAME (type) == 0)
4519 warning ("case value `%d' not in enumerated type",
4520 TREE_INT_CST_LOW (n->high));
4522 warning ("case value `%d' not in enumerated type `%s'",
4523 TREE_INT_CST_LOW (n->high),
4524 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4527 : DECL_NAME (TYPE_NAME (type))));
4533 /* ??? This optimization is disabled because it causes valid programs to
4534 fail. ANSI C does not guarantee that an expression with enum type
4535 will have a value that is the same as one of the enumation literals. */
4537 /* If all values were found as case labels, make one of them the default
4538 label. Thus, this switch will never fall through. We arbitrarily pick
4539 the last one to make the default since this is likely the most
4540 efficient choice. */
4544 for (l = &case_stack->data.case_stmt.case_list;
4549 case_stack->data.case_stmt.default_label = (*l)->code_label;
4556 /* Check that all enumeration literals are covered by the case
4557 expressions of a switch. Also warn if there are any cases
4558 that are not elements of the enumerated type. */
4561 bc_check_for_full_enumeration_handling (type)
4564 struct nesting *thiscase = case_stack;
4565 struct case_node *c;
4568 /* Check for enums not handled. */
4569 for (e = TYPE_VALUES (type); e; e = TREE_CHAIN (e))
4571 for (c = thiscase->data.case_stmt.case_list->left;
4572 c && tree_int_cst_lt (c->high, TREE_VALUE (e));
4575 if (! (c && tree_int_cst_equal (c->low, TREE_VALUE (e))))
4576 warning ("enumerated value `%s' not handled in switch",
4577 IDENTIFIER_POINTER (TREE_PURPOSE (e)));
4580 /* Check for cases not in the enumeration. */
4581 for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
4583 for (e = TYPE_VALUES (type);
4584 e && !tree_int_cst_equal (c->low, TREE_VALUE (e));
4588 warning ("case value `%d' not in enumerated type `%s'",
4589 TREE_INT_CST_LOW (c->low),
4590 IDENTIFIER_POINTER (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE
4592 : DECL_NAME (TYPE_NAME (type))));
4596 /* Terminate a case (Pascal) or switch (C) statement
4597 in which ORIG_INDEX is the expression to be tested.
4598 Generate the code to test it and jump to the right place. */
4601 expand_end_case (orig_index)
4604 tree minval, maxval, range, orig_minval;
4605 rtx default_label = 0;
4606 register struct case_node *n;
4614 register struct nesting *thiscase = case_stack;
4615 tree index_expr, index_type;
4618 if (output_bytecode)
4620 bc_expand_end_case (orig_index);
4624 table_label = gen_label_rtx ();
4625 index_expr = thiscase->data.case_stmt.index_expr;
4626 index_type = TREE_TYPE (index_expr);
4627 unsignedp = TREE_UNSIGNED (index_type);
4629 do_pending_stack_adjust ();
4631 /* An ERROR_MARK occurs for various reasons including invalid data type. */
4632 if (index_type != error_mark_node)
4634 /* If switch expression was an enumerated type, check that all
4635 enumeration literals are covered by the cases.
4636 No sense trying this if there's a default case, however. */
4638 if (!thiscase->data.case_stmt.default_label
4639 && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
4640 && TREE_CODE (index_expr) != INTEGER_CST)
4641 check_for_full_enumeration_handling (TREE_TYPE (orig_index));
4643 /* If this is the first label, warn if any insns have been emitted. */
4644 if (thiscase->data.case_stmt.seenlabel == 0)
4647 for (insn = get_last_insn ();
4648 insn != case_stack->data.case_stmt.start;
4649 insn = PREV_INSN (insn))
4650 if (GET_CODE (insn) != NOTE
4651 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn))!= USE))
4653 warning ("unreachable code at beginning of %s",
4654 case_stack->data.case_stmt.printname);
4659 /* If we don't have a default-label, create one here,
4660 after the body of the switch. */
4661 if (thiscase->data.case_stmt.default_label == 0)
4663 thiscase->data.case_stmt.default_label
4664 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
4665 expand_label (thiscase->data.case_stmt.default_label);
4667 default_label = label_rtx (thiscase->data.case_stmt.default_label);
4669 before_case = get_last_insn ();
4671 /* Simplify the case-list before we count it. */
4672 group_case_nodes (thiscase->data.case_stmt.case_list);
4674 /* Get upper and lower bounds of case values.
4675 Also convert all the case values to the index expr's data type. */
4678 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4680 /* Check low and high label values are integers. */
4681 if (TREE_CODE (n->low) != INTEGER_CST)
4683 if (TREE_CODE (n->high) != INTEGER_CST)
4686 n->low = convert (index_type, n->low);
4687 n->high = convert (index_type, n->high);
4689 /* Count the elements and track the largest and smallest
4690 of them (treating them as signed even if they are not). */
4698 if (INT_CST_LT (n->low, minval))
4700 if (INT_CST_LT (maxval, n->high))
4703 /* A range counts double, since it requires two compares. */
4704 if (! tree_int_cst_equal (n->low, n->high))
4708 orig_minval = minval;
4710 /* Compute span of values. */
4712 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
4716 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
4718 emit_jump (default_label);
4721 /* If range of values is much bigger than number of values,
4722 make a sequence of conditional branches instead of a dispatch.
4723 If the switch-index is a constant, do it this way
4724 because we can optimize it. */
4726 #ifndef CASE_VALUES_THRESHOLD
4728 #define CASE_VALUES_THRESHOLD (HAVE_casesi ? 4 : 5)
4730 /* If machine does not have a case insn that compares the
4731 bounds, this means extra overhead for dispatch tables
4732 which raises the threshold for using them. */
4733 #define CASE_VALUES_THRESHOLD 5
4734 #endif /* HAVE_casesi */
4735 #endif /* CASE_VALUES_THRESHOLD */
4737 else if (TREE_INT_CST_HIGH (range) != 0
4738 || count < CASE_VALUES_THRESHOLD
4739 || ((unsigned HOST_WIDE_INT) (TREE_INT_CST_LOW (range))
4741 || TREE_CODE (index_expr) == INTEGER_CST
4742 /* These will reduce to a constant. */
4743 || (TREE_CODE (index_expr) == CALL_EXPR
4744 && TREE_CODE (TREE_OPERAND (index_expr, 0)) == ADDR_EXPR
4745 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == FUNCTION_DECL
4746 && DECL_FUNCTION_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_CLASSIFY_TYPE)
4747 || (TREE_CODE (index_expr) == COMPOUND_EXPR
4748 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
4750 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4752 /* If the index is a short or char that we do not have
4753 an insn to handle comparisons directly, convert it to
4754 a full integer now, rather than letting each comparison
4755 generate the conversion. */
4757 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
4758 && (cmp_optab->handlers[(int) GET_MODE(index)].insn_code
4759 == CODE_FOR_nothing))
4761 enum machine_mode wider_mode;
4762 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
4763 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
4764 if (cmp_optab->handlers[(int) wider_mode].insn_code
4765 != CODE_FOR_nothing)
4767 index = convert_to_mode (wider_mode, index, unsignedp);
4773 do_pending_stack_adjust ();
4775 index = protect_from_queue (index, 0);
4776 if (GET_CODE (index) == MEM)
4777 index = copy_to_reg (index);
4778 if (GET_CODE (index) == CONST_INT
4779 || TREE_CODE (index_expr) == INTEGER_CST)
4781 /* Make a tree node with the proper constant value
4782 if we don't already have one. */
4783 if (TREE_CODE (index_expr) != INTEGER_CST)
4786 = build_int_2 (INTVAL (index),
4787 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
4788 index_expr = convert (index_type, index_expr);
4791 /* For constant index expressions we need only
4792 issue a unconditional branch to the appropriate
4793 target code. The job of removing any unreachable
4794 code is left to the optimisation phase if the
4795 "-O" option is specified. */
4796 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4797 if (! tree_int_cst_lt (index_expr, n->low)
4798 && ! tree_int_cst_lt (n->high, index_expr))
4802 emit_jump (label_rtx (n->code_label));
4804 emit_jump (default_label);
4808 /* If the index expression is not constant we generate
4809 a binary decision tree to select the appropriate
4810 target code. This is done as follows:
4812 The list of cases is rearranged into a binary tree,
4813 nearly optimal assuming equal probability for each case.
4815 The tree is transformed into RTL, eliminating
4816 redundant test conditions at the same time.
4818 If program flow could reach the end of the
4819 decision tree an unconditional jump to the
4820 default code is emitted. */
4823 = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
4824 && estimate_case_costs (thiscase->data.case_stmt.case_list));
4825 balance_case_nodes (&thiscase->data.case_stmt.case_list,
4827 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
4828 default_label, index_type);
4829 emit_jump_if_reachable (default_label);
4838 enum machine_mode index_mode = SImode;
4839 int index_bits = GET_MODE_BITSIZE (index_mode);
4841 enum machine_mode op_mode;
4843 /* Convert the index to SImode. */
4844 if (GET_MODE_BITSIZE (TYPE_MODE (index_type))
4845 > GET_MODE_BITSIZE (index_mode))
4847 enum machine_mode omode = TYPE_MODE (index_type);
4848 rtx rangertx = expand_expr (range, NULL_RTX, VOIDmode, 0);
4850 /* We must handle the endpoints in the original mode. */
4851 index_expr = build (MINUS_EXPR, index_type,
4852 index_expr, minval);
4853 minval = integer_zero_node;
4854 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4855 emit_cmp_insn (rangertx, index, LTU, NULL_RTX, omode, 1, 0);
4856 emit_jump_insn (gen_bltu (default_label));
4857 /* Now we can safely truncate. */
4858 index = convert_to_mode (index_mode, index, 0);
4862 if (TYPE_MODE (index_type) != index_mode)
4864 index_expr = convert (type_for_size (index_bits, 0),
4866 index_type = TREE_TYPE (index_expr);
4869 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4872 index = protect_from_queue (index, 0);
4873 do_pending_stack_adjust ();
4875 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][0];
4876 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][0])
4878 index = copy_to_mode_reg (op_mode, index);
4880 op1 = expand_expr (minval, NULL_RTX, VOIDmode, 0);
4882 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][1];
4883 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][1])
4885 op1 = copy_to_mode_reg (op_mode, op1);
4887 op2 = expand_expr (range, NULL_RTX, VOIDmode, 0);
4889 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][2];
4890 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][2])
4892 op2 = copy_to_mode_reg (op_mode, op2);
4894 emit_jump_insn (gen_casesi (index, op1, op2,
4895 table_label, default_label));
4899 #ifdef HAVE_tablejump
4900 if (! win && HAVE_tablejump)
4902 index_expr = convert (thiscase->data.case_stmt.nominal_type,
4903 fold (build (MINUS_EXPR, index_type,
4904 index_expr, minval)));
4905 index_type = TREE_TYPE (index_expr);
4906 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4908 index = protect_from_queue (index, 0);
4909 do_pending_stack_adjust ();
4911 do_tablejump (index, TYPE_MODE (index_type),
4912 expand_expr (range, NULL_RTX, VOIDmode, 0),
4913 table_label, default_label);
4920 /* Get table of labels to jump to, in order of case index. */
4922 ncases = TREE_INT_CST_LOW (range) + 1;
4923 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
4924 bzero ((char *) labelvec, ncases * sizeof (rtx));
4926 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4928 register HOST_WIDE_INT i
4929 = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
4934 = gen_rtx (LABEL_REF, Pmode, label_rtx (n->code_label));
4935 if (i + TREE_INT_CST_LOW (orig_minval)
4936 == TREE_INT_CST_LOW (n->high))
4942 /* Fill in the gaps with the default. */
4943 for (i = 0; i < ncases; i++)
4944 if (labelvec[i] == 0)
4945 labelvec[i] = gen_rtx (LABEL_REF, Pmode, default_label);
4947 /* Output the table */
4948 emit_label (table_label);
4950 /* This would be a lot nicer if CASE_VECTOR_PC_RELATIVE
4951 were an expression, instead of an #ifdef/#ifndef. */
4953 #ifdef CASE_VECTOR_PC_RELATIVE
4957 emit_jump_insn (gen_rtx (ADDR_DIFF_VEC, CASE_VECTOR_MODE,
4958 gen_rtx (LABEL_REF, Pmode, table_label),
4959 gen_rtvec_v (ncases, labelvec)));
4961 emit_jump_insn (gen_rtx (ADDR_VEC, CASE_VECTOR_MODE,
4962 gen_rtvec_v (ncases, labelvec)));
4964 /* If the case insn drops through the table,
4965 after the table we must jump to the default-label.
4966 Otherwise record no drop-through after the table. */
4967 #ifdef CASE_DROPS_THROUGH
4968 emit_jump (default_label);
4974 before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
4975 reorder_insns (before_case, get_last_insn (),
4976 thiscase->data.case_stmt.start);
4979 if (thiscase->exit_label)
4980 emit_label (thiscase->exit_label);
4982 POPSTACK (case_stack);
4988 /* Terminate a case statement. EXPR is the original index
4992 bc_expand_end_case (expr)
4995 struct nesting *thiscase = case_stack;
4996 enum bytecode_opcode opcode;
4997 struct bc_label *jump_label;
4998 struct case_node *c;
5000 bc_emit_bytecode (jump);
5001 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->exit_label));
5003 #ifdef DEBUG_PRINT_CODE
5004 fputc ('\n', stderr);
5007 /* Now that the size of the jump table is known, emit the actual
5008 indexed jump instruction. */
5009 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscase->data.case_stmt.skip_label));
5011 opcode = TYPE_MODE (thiscase->data.case_stmt.nominal_type) == SImode
5012 ? TREE_UNSIGNED (thiscase->data.case_stmt.nominal_type) ? caseSU : caseSI
5013 : TREE_UNSIGNED (thiscase->data.case_stmt.nominal_type) ? caseDU : caseDI;
5015 bc_emit_bytecode (opcode);
5017 /* Now emit the case instructions literal arguments, in order.
5018 In addition to the value on the stack, it uses:
5019 1. The address of the jump table.
5020 2. The size of the jump table.
5021 3. The default label. */
5023 jump_label = bc_get_bytecode_label ();
5024 bc_emit_bytecode_labelref (jump_label);
5025 bc_emit_bytecode_const ((char *) &thiscase->data.case_stmt.num_ranges,
5026 sizeof thiscase->data.case_stmt.num_ranges);
5028 if (thiscase->data.case_stmt.default_label)
5029 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (thiscase->data.case_stmt.default_label)));
5031 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->exit_label));
5033 /* Output the jump table. */
5035 bc_align_bytecode (3 /* PTR_ALIGN */);
5036 bc_emit_bytecode_labeldef (jump_label);
5038 if (TYPE_MODE (thiscase->data.case_stmt.nominal_type) == SImode)
5039 for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
5041 opcode = TREE_INT_CST_LOW (c->low);
5042 bc_emit_bytecode_const ((char *) &opcode, sizeof opcode);
5044 opcode = TREE_INT_CST_LOW (c->high);
5045 bc_emit_bytecode_const ((char *) &opcode, sizeof opcode);
5047 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (c->code_label)));
5050 if (TYPE_MODE (thiscase->data.case_stmt.nominal_type) == DImode)
5051 for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
5053 bc_emit_bytecode_DI_const (c->low);
5054 bc_emit_bytecode_DI_const (c->high);
5056 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (c->code_label)));
5063 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscase->exit_label));
5065 /* Possibly issue enumeration warnings. */
5067 if (!thiscase->data.case_stmt.default_label
5068 && TREE_CODE (TREE_TYPE (expr)) == ENUMERAL_TYPE
5069 && TREE_CODE (expr) != INTEGER_CST
5071 check_for_full_enumeration_handling (TREE_TYPE (expr));
5074 #ifdef DEBUG_PRINT_CODE
5075 fputc ('\n', stderr);
5078 POPSTACK (case_stack);
5082 /* Return unique bytecode ID. */
5087 static int bc_uid = 0;
5092 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5095 do_jump_if_equal (op1, op2, label, unsignedp)
5096 rtx op1, op2, label;
5099 if (GET_CODE (op1) == CONST_INT
5100 && GET_CODE (op2) == CONST_INT)
5102 if (INTVAL (op1) == INTVAL (op2))
5107 enum machine_mode mode = GET_MODE (op1);
5108 if (mode == VOIDmode)
5109 mode = GET_MODE (op2);
5110 emit_cmp_insn (op1, op2, EQ, NULL_RTX, mode, unsignedp, 0);
5111 emit_jump_insn (gen_beq (label));
5115 /* Not all case values are encountered equally. This function
5116 uses a heuristic to weight case labels, in cases where that
5117 looks like a reasonable thing to do.
5119 Right now, all we try to guess is text, and we establish the
5122 chars above space: 16
5131 If we find any cases in the switch that are not either -1 or in the range
5132 of valid ASCII characters, or are control characters other than those
5133 commonly used with "\", don't treat this switch scanning text.
5135 Return 1 if these nodes are suitable for cost estimation, otherwise
5139 estimate_case_costs (node)
5142 tree min_ascii = build_int_2 (-1, -1);
5143 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5147 /* If we haven't already made the cost table, make it now. Note that the
5148 lower bound of the table is -1, not zero. */
5150 if (cost_table == NULL)
5152 cost_table = ((short *) xmalloc (129 * sizeof (short))) + 1;
5153 bzero ((char *) (cost_table - 1), 129 * sizeof (short));
5155 for (i = 0; i < 128; i++)
5159 else if (ispunct (i))
5161 else if (iscntrl (i))
5165 cost_table[' '] = 8;
5166 cost_table['\t'] = 4;
5167 cost_table['\0'] = 4;
5168 cost_table['\n'] = 2;
5169 cost_table['\f'] = 1;
5170 cost_table['\v'] = 1;
5171 cost_table['\b'] = 1;
5174 /* See if all the case expressions look like text. It is text if the
5175 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5176 as signed arithmetic since we don't want to ever access cost_table with a
5177 value less than -1. Also check that none of the constants in a range
5178 are strange control characters. */
5180 for (n = node; n; n = n->right)
5182 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5185 for (i = TREE_INT_CST_LOW (n->low); i <= TREE_INT_CST_LOW (n->high); i++)
5186 if (cost_table[i] < 0)
5190 /* All interesting values are within the range of interesting
5191 ASCII characters. */
5195 /* Scan an ordered list of case nodes
5196 combining those with consecutive values or ranges.
5198 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5201 group_case_nodes (head)
5204 case_node_ptr node = head;
5208 rtx lb = next_real_insn (label_rtx (node->code_label));
5209 case_node_ptr np = node;
5211 /* Try to group the successors of NODE with NODE. */
5212 while (((np = np->right) != 0)
5213 /* Do they jump to the same place? */
5214 && next_real_insn (label_rtx (np->code_label)) == lb
5215 /* Are their ranges consecutive? */
5216 && tree_int_cst_equal (np->low,
5217 fold (build (PLUS_EXPR,
5218 TREE_TYPE (node->high),
5221 /* An overflow is not consecutive. */
5222 && tree_int_cst_lt (node->high,
5223 fold (build (PLUS_EXPR,
5224 TREE_TYPE (node->high),
5226 integer_one_node))))
5228 node->high = np->high;
5230 /* NP is the first node after NODE which can't be grouped with it.
5231 Delete the nodes in between, and move on to that node. */
5237 /* Take an ordered list of case nodes
5238 and transform them into a near optimal binary tree,
5239 on the assumption that any target code selection value is as
5240 likely as any other.
5242 The transformation is performed by splitting the ordered
5243 list into two equal sections plus a pivot. The parts are
5244 then attached to the pivot as left and right branches. Each
5245 branch is is then transformed recursively. */
5248 balance_case_nodes (head, parent)
5249 case_node_ptr *head;
5250 case_node_ptr parent;
5252 register case_node_ptr np;
5260 register case_node_ptr *npp;
5263 /* Count the number of entries on branch. Also count the ranges. */
5267 if (!tree_int_cst_equal (np->low, np->high))
5271 cost += cost_table[TREE_INT_CST_LOW (np->high)];
5275 cost += cost_table[TREE_INT_CST_LOW (np->low)];
5283 /* Split this list if it is long enough for that to help. */
5288 /* Find the place in the list that bisects the list's total cost,
5289 Here I gets half the total cost. */
5294 /* Skip nodes while their cost does not reach that amount. */
5295 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5296 i -= cost_table[TREE_INT_CST_LOW ((*npp)->high)];
5297 i -= cost_table[TREE_INT_CST_LOW ((*npp)->low)];
5300 npp = &(*npp)->right;
5305 /* Leave this branch lopsided, but optimize left-hand
5306 side and fill in `parent' fields for right-hand side. */
5308 np->parent = parent;
5309 balance_case_nodes (&np->left, np);
5310 for (; np->right; np = np->right)
5311 np->right->parent = np;
5315 /* If there are just three nodes, split at the middle one. */
5317 npp = &(*npp)->right;
5320 /* Find the place in the list that bisects the list's total cost,
5321 where ranges count as 2.
5322 Here I gets half the total cost. */
5323 i = (i + ranges + 1) / 2;
5326 /* Skip nodes while their cost does not reach that amount. */
5327 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5332 npp = &(*npp)->right;
5337 np->parent = parent;
5340 /* Optimize each of the two split parts. */
5341 balance_case_nodes (&np->left, np);
5342 balance_case_nodes (&np->right, np);
5346 /* Else leave this branch as one level,
5347 but fill in `parent' fields. */
5349 np->parent = parent;
5350 for (; np->right; np = np->right)
5351 np->right->parent = np;
5356 /* Search the parent sections of the case node tree
5357 to see if a test for the lower bound of NODE would be redundant.
5358 INDEX_TYPE is the type of the index expression.
5360 The instructions to generate the case decision tree are
5361 output in the same order as nodes are processed so it is
5362 known that if a parent node checks the range of the current
5363 node minus one that the current node is bounded at its lower
5364 span. Thus the test would be redundant. */
5367 node_has_low_bound (node, index_type)
5372 case_node_ptr pnode;
5374 /* If the lower bound of this node is the lowest value in the index type,
5375 we need not test it. */
5377 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5380 /* If this node has a left branch, the value at the left must be less
5381 than that at this node, so it cannot be bounded at the bottom and
5382 we need not bother testing any further. */
5387 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5388 node->low, integer_one_node));
5390 /* If the subtraction above overflowed, we can't verify anything.
5391 Otherwise, look for a parent that tests our value - 1. */
5393 if (! tree_int_cst_lt (low_minus_one, node->low))
5396 for (pnode = node->parent; pnode; pnode = pnode->parent)
5397 if (tree_int_cst_equal (low_minus_one, pnode->high))
5403 /* Search the parent sections of the case node tree
5404 to see if a test for the upper bound of NODE would be redundant.
5405 INDEX_TYPE is the type of the index expression.
5407 The instructions to generate the case decision tree are
5408 output in the same order as nodes are processed so it is
5409 known that if a parent node checks the range of the current
5410 node plus one that the current node is bounded at its upper
5411 span. Thus the test would be redundant. */
5414 node_has_high_bound (node, index_type)
5419 case_node_ptr pnode;
5421 /* If the upper bound of this node is the highest value in the type
5422 of the index expression, we need not test against it. */
5424 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5427 /* If this node has a right branch, the value at the right must be greater
5428 than that at this node, so it cannot be bounded at the top and
5429 we need not bother testing any further. */
5434 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5435 node->high, integer_one_node));
5437 /* If the addition above overflowed, we can't verify anything.
5438 Otherwise, look for a parent that tests our value + 1. */
5440 if (! tree_int_cst_lt (node->high, high_plus_one))
5443 for (pnode = node->parent; pnode; pnode = pnode->parent)
5444 if (tree_int_cst_equal (high_plus_one, pnode->low))
5450 /* Search the parent sections of the
5451 case node tree to see if both tests for the upper and lower
5452 bounds of NODE would be redundant. */
5455 node_is_bounded (node, index_type)
5459 return (node_has_low_bound (node, index_type)
5460 && node_has_high_bound (node, index_type));
5463 /* Emit an unconditional jump to LABEL unless it would be dead code. */
5466 emit_jump_if_reachable (label)
5469 if (GET_CODE (get_last_insn ()) != BARRIER)
5473 /* Emit step-by-step code to select a case for the value of INDEX.
5474 The thus generated decision tree follows the form of the
5475 case-node binary tree NODE, whose nodes represent test conditions.
5476 INDEX_TYPE is the type of the index of the switch.
5478 Care is taken to prune redundant tests from the decision tree
5479 by detecting any boundary conditions already checked by
5480 emitted rtx. (See node_has_high_bound, node_has_low_bound
5481 and node_is_bounded, above.)
5483 Where the test conditions can be shown to be redundant we emit
5484 an unconditional jump to the target code. As a further
5485 optimization, the subordinates of a tree node are examined to
5486 check for bounded nodes. In this case conditional and/or
5487 unconditional jumps as a result of the boundary check for the
5488 current node are arranged to target the subordinates associated
5489 code for out of bound conditions on the current node node.
5491 We can assume that when control reaches the code generated here,
5492 the index value has already been compared with the parents
5493 of this node, and determined to be on the same side of each parent
5494 as this node is. Thus, if this node tests for the value 51,
5495 and a parent tested for 52, we don't need to consider
5496 the possibility of a value greater than 51. If another parent
5497 tests for the value 50, then this node need not test anything. */
5500 emit_case_nodes (index, node, default_label, index_type)
5506 /* If INDEX has an unsigned type, we must make unsigned branches. */
5507 int unsignedp = TREE_UNSIGNED (index_type);
5508 typedef rtx rtx_function ();
5509 rtx_function *gen_bgt_pat = unsignedp ? gen_bgtu : gen_bgt;
5510 rtx_function *gen_bge_pat = unsignedp ? gen_bgeu : gen_bge;
5511 rtx_function *gen_blt_pat = unsignedp ? gen_bltu : gen_blt;
5512 rtx_function *gen_ble_pat = unsignedp ? gen_bleu : gen_ble;
5513 enum machine_mode mode = GET_MODE (index);
5515 /* See if our parents have already tested everything for us.
5516 If they have, emit an unconditional jump for this node. */
5517 if (node_is_bounded (node, index_type))
5518 emit_jump (label_rtx (node->code_label));
5520 else if (tree_int_cst_equal (node->low, node->high))
5522 /* Node is single valued. First see if the index expression matches
5523 this node and then check our children, if any. */
5525 do_jump_if_equal (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5526 label_rtx (node->code_label), unsignedp);
5528 if (node->right != 0 && node->left != 0)
5530 /* This node has children on both sides.
5531 Dispatch to one side or the other
5532 by comparing the index value with this node's value.
5533 If one subtree is bounded, check that one first,
5534 so we can avoid real branches in the tree. */
5536 if (node_is_bounded (node->right, index_type))
5538 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5540 GT, NULL_RTX, mode, unsignedp, 0);
5542 emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
5543 emit_case_nodes (index, node->left, default_label, index_type);
5546 else if (node_is_bounded (node->left, index_type))
5548 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5550 LT, NULL_RTX, mode, unsignedp, 0);
5551 emit_jump_insn ((*gen_blt_pat) (label_rtx (node->left->code_label)));
5552 emit_case_nodes (index, node->right, default_label, index_type);
5557 /* Neither node is bounded. First distinguish the two sides;
5558 then emit the code for one side at a time. */
5561 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5563 /* See if the value is on the right. */
5564 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5566 GT, NULL_RTX, mode, unsignedp, 0);
5567 emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
5569 /* Value must be on the left.
5570 Handle the left-hand subtree. */
5571 emit_case_nodes (index, node->left, default_label, index_type);
5572 /* If left-hand subtree does nothing,
5574 emit_jump_if_reachable (default_label);
5576 /* Code branches here for the right-hand subtree. */
5577 expand_label (test_label);
5578 emit_case_nodes (index, node->right, default_label, index_type);
5582 else if (node->right != 0 && node->left == 0)
5584 /* Here we have a right child but no left so we issue conditional
5585 branch to default and process the right child.
5587 Omit the conditional branch to default if we it avoid only one
5588 right child; it costs too much space to save so little time. */
5590 if (node->right->right || node->right->left
5591 || !tree_int_cst_equal (node->right->low, node->right->high))
5593 if (!node_has_low_bound (node, index_type))
5595 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5597 LT, NULL_RTX, mode, unsignedp, 0);
5598 emit_jump_insn ((*gen_blt_pat) (default_label));
5601 emit_case_nodes (index, node->right, default_label, index_type);
5604 /* We cannot process node->right normally
5605 since we haven't ruled out the numbers less than
5606 this node's value. So handle node->right explicitly. */
5607 do_jump_if_equal (index,
5608 expand_expr (node->right->low, NULL_RTX,
5610 label_rtx (node->right->code_label), unsignedp);
5613 else if (node->right == 0 && node->left != 0)
5615 /* Just one subtree, on the left. */
5617 #if 0 /* The following code and comment were formerly part
5618 of the condition here, but they didn't work
5619 and I don't understand what the idea was. -- rms. */
5620 /* If our "most probable entry" is less probable
5621 than the default label, emit a jump to
5622 the default label using condition codes
5623 already lying around. With no right branch,
5624 a branch-greater-than will get us to the default
5627 && cost_table[TREE_INT_CST_LOW (node->high)] < 12)
5630 if (node->left->left || node->left->right
5631 || !tree_int_cst_equal (node->left->low, node->left->high))
5633 if (!node_has_high_bound (node, index_type))
5635 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5637 GT, NULL_RTX, mode, unsignedp, 0);
5638 emit_jump_insn ((*gen_bgt_pat) (default_label));
5641 emit_case_nodes (index, node->left, default_label, index_type);
5644 /* We cannot process node->left normally
5645 since we haven't ruled out the numbers less than
5646 this node's value. So handle node->left explicitly. */
5647 do_jump_if_equal (index,
5648 expand_expr (node->left->low, NULL_RTX,
5650 label_rtx (node->left->code_label), unsignedp);
5655 /* Node is a range. These cases are very similar to those for a single
5656 value, except that we do not start by testing whether this node
5657 is the one to branch to. */
5659 if (node->right != 0 && node->left != 0)
5661 /* Node has subtrees on both sides.
5662 If the right-hand subtree is bounded,
5663 test for it first, since we can go straight there.
5664 Otherwise, we need to make a branch in the control structure,
5665 then handle the two subtrees. */
5666 tree test_label = 0;
5668 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5670 GT, NULL_RTX, mode, unsignedp, 0);
5672 if (node_is_bounded (node->right, index_type))
5673 /* Right hand node is fully bounded so we can eliminate any
5674 testing and branch directly to the target code. */
5675 emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
5678 /* Right hand node requires testing.
5679 Branch to a label where we will handle it later. */
5681 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5682 emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
5685 /* Value belongs to this node or to the left-hand subtree. */
5687 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5688 GE, NULL_RTX, mode, unsignedp, 0);
5689 emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
5691 /* Handle the left-hand subtree. */
5692 emit_case_nodes (index, node->left, default_label, index_type);
5694 /* If right node had to be handled later, do that now. */
5698 /* If the left-hand subtree fell through,
5699 don't let it fall into the right-hand subtree. */
5700 emit_jump_if_reachable (default_label);
5702 expand_label (test_label);
5703 emit_case_nodes (index, node->right, default_label, index_type);
5707 else if (node->right != 0 && node->left == 0)
5709 /* Deal with values to the left of this node,
5710 if they are possible. */
5711 if (!node_has_low_bound (node, index_type))
5713 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
5715 LT, NULL_RTX, mode, unsignedp, 0);
5716 emit_jump_insn ((*gen_blt_pat) (default_label));
5719 /* Value belongs to this node or to the right-hand subtree. */
5721 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5723 LE, NULL_RTX, mode, unsignedp, 0);
5724 emit_jump_insn ((*gen_ble_pat) (label_rtx (node->code_label)));
5726 emit_case_nodes (index, node->right, default_label, index_type);
5729 else if (node->right == 0 && node->left != 0)
5731 /* Deal with values to the right of this node,
5732 if they are possible. */
5733 if (!node_has_high_bound (node, index_type))
5735 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5737 GT, NULL_RTX, mode, unsignedp, 0);
5738 emit_jump_insn ((*gen_bgt_pat) (default_label));
5741 /* Value belongs to this node or to the left-hand subtree. */
5743 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5744 GE, NULL_RTX, mode, unsignedp, 0);
5745 emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
5747 emit_case_nodes (index, node->left, default_label, index_type);
5752 /* Node has no children so we check low and high bounds to remove
5753 redundant tests. Only one of the bounds can exist,
5754 since otherwise this node is bounded--a case tested already. */
5756 if (!node_has_high_bound (node, index_type))
5758 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5760 GT, NULL_RTX, mode, unsignedp, 0);
5761 emit_jump_insn ((*gen_bgt_pat) (default_label));
5764 if (!node_has_low_bound (node, index_type))
5766 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
5768 LT, NULL_RTX, mode, unsignedp, 0);
5769 emit_jump_insn ((*gen_blt_pat) (default_label));
5772 emit_jump (label_rtx (node->code_label));
5777 /* These routines are used by the loop unrolling code. They copy BLOCK trees
5778 so that the debugging info will be correct for the unrolled loop. */
5780 /* Indexed by block number, contains a pointer to the N'th block node. */
5782 static tree *block_vector;
5785 find_loop_tree_blocks ()
5787 tree block = DECL_INITIAL (current_function_decl);
5789 /* There first block is for the function body, and does not have
5790 corresponding block notes. Don't include it in the block vector. */
5791 block = BLOCK_SUBBLOCKS (block);
5793 block_vector = identify_blocks (block, get_insns ());
5797 unroll_block_trees ()
5799 tree block = DECL_INITIAL (current_function_decl);
5801 reorder_blocks (block_vector, block, get_insns ());