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 cleanup_insns = get_insns ();
1249 = emit_insns_after (cleanup_insns, f->before_jump);
1251 TREE_VALUE (lists) = 0;
1255 f->stack_level = stack_level;
1260 /* When exiting a binding contour, process all pending gotos requiring fixups.
1261 Note: STACK_DEPTH is not altered.
1263 The arguments are currently not used in the bytecode compiler, but we may
1264 need them one day for languages other than C.
1266 THISBLOCK is the structure that describes the block being exited.
1267 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
1268 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
1269 FIRST_INSN is the insn that began this contour.
1271 Gotos that jump out of this contour must restore the
1272 stack level and do the cleanups before actually jumping.
1274 DONT_JUMP_IN nonzero means report error there is a jump into this
1275 contour from before the beginning of the contour.
1276 This is also done if STACK_LEVEL is nonzero. */
1279 bc_fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
1280 struct nesting *thisblock;
1286 register struct goto_fixup *f, *prev;
1287 int saved_stack_depth;
1289 /* F is the fixup we are considering; PREV is the previous one. */
1291 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1293 /* Test for a fixup that is inactive because it is already handled. */
1294 if (f->before_jump == 0)
1296 /* Delete inactive fixup from the chain, if that is easy to do. */
1298 prev->next = f->next;
1301 /* Emit code to restore the stack and continue */
1302 bc_emit_bytecode_labeldef (f->label);
1304 /* Save stack_depth across call, since bc_adjust_stack () will alter
1305 the perceived stack depth via the instructions generated. */
1307 if (f->bc_stack_level >= 0)
1309 saved_stack_depth = stack_depth;
1310 bc_adjust_stack (stack_depth - f->bc_stack_level);
1311 stack_depth = saved_stack_depth;
1314 bc_emit_bytecode (jump);
1315 bc_emit_bytecode_labelref (f->bc_target);
1317 #ifdef DEBUG_PRINT_CODE
1318 fputc ('\n', stderr);
1322 goto_fixup_chain = NULL;
1325 /* Generate RTL for an asm statement (explicit assembler code).
1326 BODY is a STRING_CST node containing the assembler code text,
1327 or an ADDR_EXPR containing a STRING_CST. */
1333 if (output_bytecode)
1335 error ("`asm' is invalid when generating bytecode");
1339 if (TREE_CODE (body) == ADDR_EXPR)
1340 body = TREE_OPERAND (body, 0);
1342 emit_insn (gen_rtx (ASM_INPUT, VOIDmode,
1343 TREE_STRING_POINTER (body)));
1347 /* Generate RTL for an asm statement with arguments.
1348 STRING is the instruction template.
1349 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1350 Each output or input has an expression in the TREE_VALUE and
1351 a constraint-string in the TREE_PURPOSE.
1352 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1353 that is clobbered by this insn.
1355 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1356 Some elements of OUTPUTS may be replaced with trees representing temporary
1357 values. The caller should copy those temporary values to the originally
1360 VOL nonzero means the insn is volatile; don't optimize it. */
1363 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1364 tree string, outputs, inputs, clobbers;
1369 rtvec argvec, constraints;
1371 int ninputs = list_length (inputs);
1372 int noutputs = list_length (outputs);
1376 /* Vector of RTX's of evaluated output operands. */
1377 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1378 /* The insn we have emitted. */
1381 if (output_bytecode)
1383 error ("`asm' is invalid when generating bytecode");
1387 /* Count the number of meaningful clobbered registers, ignoring what
1388 we would ignore later. */
1390 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1392 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1393 i = decode_reg_name (regname);
1394 if (i >= 0 || i == -4)
1397 error ("unknown register name `%s' in `asm'", regname);
1402 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1404 tree val = TREE_VALUE (tail);
1409 /* If there's an erroneous arg, emit no insn. */
1410 if (TREE_TYPE (val) == error_mark_node)
1413 /* Make sure constraint has `=' and does not have `+'. */
1416 for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1418 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1420 error ("output operand constraint contains `+'");
1423 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '=')
1428 error ("output operand constraint lacks `='");
1432 /* If an output operand is not a variable or indirect ref,
1434 create a SAVE_EXPR which is a pseudo-reg
1435 to act as an intermediate temporary.
1436 Make the asm insn write into that, then copy it to
1437 the real output operand. */
1439 while (TREE_CODE (val) == COMPONENT_REF
1440 || TREE_CODE (val) == ARRAY_REF)
1441 val = TREE_OPERAND (val, 0);
1443 if (TREE_CODE (val) != VAR_DECL
1444 && TREE_CODE (val) != PARM_DECL
1445 && TREE_CODE (val) != INDIRECT_REF)
1447 TREE_VALUE (tail) = save_expr (TREE_VALUE (tail));
1448 /* If it's a constant, print error now so don't crash later. */
1449 if (TREE_CODE (TREE_VALUE (tail)) != SAVE_EXPR)
1451 error ("invalid output in `asm'");
1456 output_rtx[i] = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1459 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1461 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1465 /* Make vectors for the expression-rtx and constraint strings. */
1467 argvec = rtvec_alloc (ninputs);
1468 constraints = rtvec_alloc (ninputs);
1470 body = gen_rtx (ASM_OPERANDS, VOIDmode,
1471 TREE_STRING_POINTER (string), "", 0, argvec, constraints,
1473 MEM_VOLATILE_P (body) = vol;
1475 /* Eval the inputs and put them into ARGVEC.
1476 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1479 for (tail = inputs; tail; tail = TREE_CHAIN (tail))
1483 /* If there's an erroneous arg, emit no insn,
1484 because the ASM_INPUT would get VOIDmode
1485 and that could cause a crash in reload. */
1486 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1488 if (TREE_PURPOSE (tail) == NULL_TREE)
1490 error ("hard register `%s' listed as input operand to `asm'",
1491 TREE_STRING_POINTER (TREE_VALUE (tail)) );
1495 /* Make sure constraint has neither `=' nor `+'. */
1497 for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1498 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '='
1499 || TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1501 error ("input operand constraint contains `%c'",
1502 TREE_STRING_POINTER (TREE_PURPOSE (tail))[j]);
1506 XVECEXP (body, 3, i) /* argvec */
1507 = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1508 if (CONSTANT_P (XVECEXP (body, 3, i))
1509 && ! general_operand (XVECEXP (body, 3, i),
1510 TYPE_MODE (TREE_TYPE (TREE_VALUE (tail)))))
1511 XVECEXP (body, 3, i)
1512 = force_reg (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1513 XVECEXP (body, 3, i));
1514 XVECEXP (body, 4, i) /* constraints */
1515 = gen_rtx (ASM_INPUT, TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1516 TREE_STRING_POINTER (TREE_PURPOSE (tail)));
1520 /* Protect all the operands from the queue,
1521 now that they have all been evaluated. */
1523 for (i = 0; i < ninputs; i++)
1524 XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
1526 for (i = 0; i < noutputs; i++)
1527 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1529 /* Now, for each output, construct an rtx
1530 (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
1531 ARGVEC CONSTRAINTS))
1532 If there is more than one, put them inside a PARALLEL. */
1534 if (noutputs == 1 && nclobbers == 0)
1536 XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
1537 insn = emit_insn (gen_rtx (SET, VOIDmode, output_rtx[0], body));
1539 else if (noutputs == 0 && nclobbers == 0)
1541 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1542 insn = emit_insn (body);
1548 if (num == 0) num = 1;
1549 body = gen_rtx (PARALLEL, VOIDmode, rtvec_alloc (num + nclobbers));
1551 /* For each output operand, store a SET. */
1553 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1555 XVECEXP (body, 0, i)
1556 = gen_rtx (SET, VOIDmode,
1558 gen_rtx (ASM_OPERANDS, VOIDmode,
1559 TREE_STRING_POINTER (string),
1560 TREE_STRING_POINTER (TREE_PURPOSE (tail)),
1561 i, argvec, constraints,
1563 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1566 /* If there are no outputs (but there are some clobbers)
1567 store the bare ASM_OPERANDS into the PARALLEL. */
1570 XVECEXP (body, 0, i++) = obody;
1572 /* Store (clobber REG) for each clobbered register specified. */
1574 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1576 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1577 int j = decode_reg_name (regname);
1581 if (j == -3) /* `cc', which is not a register */
1584 if (j == -4) /* `memory', don't cache memory across asm */
1586 XVECEXP (body, 0, i++)
1587 = gen_rtx (CLOBBER, VOIDmode,
1588 gen_rtx (MEM, BLKmode,
1589 gen_rtx (SCRATCH, VOIDmode, 0)));
1593 /* Ignore unknown register, error already signalled. */
1596 /* Use QImode since that's guaranteed to clobber just one reg. */
1597 XVECEXP (body, 0, i++)
1598 = gen_rtx (CLOBBER, VOIDmode, gen_rtx (REG, QImode, j));
1601 insn = emit_insn (body);
1607 /* Generate RTL to evaluate the expression EXP
1608 and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
1611 expand_expr_stmt (exp)
1614 if (output_bytecode)
1616 int org_stack_depth = stack_depth;
1618 bc_expand_expr (exp);
1620 /* Restore stack depth */
1621 if (stack_depth < org_stack_depth)
1624 bc_emit_instruction (drop);
1626 last_expr_type = TREE_TYPE (exp);
1630 /* If -W, warn about statements with no side effects,
1631 except for an explicit cast to void (e.g. for assert()), and
1632 except inside a ({...}) where they may be useful. */
1633 if (expr_stmts_for_value == 0 && exp != error_mark_node)
1635 if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
1636 && !(TREE_CODE (exp) == CONVERT_EXPR
1637 && TREE_TYPE (exp) == void_type_node))
1638 warning_with_file_and_line (emit_filename, emit_lineno,
1639 "statement with no effect");
1640 else if (warn_unused)
1641 warn_if_unused_value (exp);
1644 /* If EXP is of function type and we are expanding statements for
1645 value, convert it to pointer-to-function. */
1646 if (expr_stmts_for_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
1647 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
1649 last_expr_type = TREE_TYPE (exp);
1650 if (! flag_syntax_only)
1651 last_expr_value = expand_expr (exp,
1652 (expr_stmts_for_value
1653 ? NULL_RTX : const0_rtx),
1656 /* If all we do is reference a volatile value in memory,
1657 copy it to a register to be sure it is actually touched. */
1658 if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
1659 && TREE_THIS_VOLATILE (exp))
1661 if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
1663 else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
1664 copy_to_reg (last_expr_value);
1667 rtx lab = gen_label_rtx ();
1669 /* Compare the value with itself to reference it. */
1670 emit_cmp_insn (last_expr_value, last_expr_value, EQ,
1671 expand_expr (TYPE_SIZE (last_expr_type),
1672 NULL_RTX, VOIDmode, 0),
1674 TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT);
1675 emit_jump_insn ((*bcc_gen_fctn[(int) EQ]) (lab));
1680 /* If this expression is part of a ({...}) and is in memory, we may have
1681 to preserve temporaries. */
1682 preserve_temp_slots (last_expr_value);
1684 /* Free any temporaries used to evaluate this expression. Any temporary
1685 used as a result of this expression will already have been preserved
1692 /* Warn if EXP contains any computations whose results are not used.
1693 Return 1 if a warning is printed; 0 otherwise. */
1696 warn_if_unused_value (exp)
1699 if (TREE_USED (exp))
1702 switch (TREE_CODE (exp))
1704 case PREINCREMENT_EXPR:
1705 case POSTINCREMENT_EXPR:
1706 case PREDECREMENT_EXPR:
1707 case POSTDECREMENT_EXPR:
1712 case METHOD_CALL_EXPR:
1714 case WITH_CLEANUP_EXPR:
1716 /* We don't warn about COND_EXPR because it may be a useful
1717 construct if either arm contains a side effect. */
1722 /* For a binding, warn if no side effect within it. */
1723 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1726 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1728 case TRUTH_ORIF_EXPR:
1729 case TRUTH_ANDIF_EXPR:
1730 /* In && or ||, warn if 2nd operand has no side effect. */
1731 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1734 if (TREE_NO_UNUSED_WARNING (exp))
1736 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
1738 /* Let people do `(foo (), 0)' without a warning. */
1739 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1741 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1745 case NON_LVALUE_EXPR:
1746 /* Don't warn about values cast to void. */
1747 if (TREE_TYPE (exp) == void_type_node)
1749 /* Don't warn about conversions not explicit in the user's program. */
1750 if (TREE_NO_UNUSED_WARNING (exp))
1752 /* Assignment to a cast usually results in a cast of a modify.
1753 Don't complain about that. There can be an arbitrary number of
1754 casts before the modify, so we must loop until we find the first
1755 non-cast expression and then test to see if that is a modify. */
1757 tree tem = TREE_OPERAND (exp, 0);
1759 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1760 tem = TREE_OPERAND (tem, 0);
1762 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
1763 || TREE_CODE (tem) == CALL_EXPR)
1769 /* Don't warn about automatic dereferencing of references, since
1770 the user cannot control it. */
1771 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
1772 return warn_if_unused_value (TREE_OPERAND (exp, 0));
1773 /* ... fall through ... */
1776 /* Referencing a volatile value is a side effect, so don't warn. */
1777 if ((TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
1778 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1779 && TREE_THIS_VOLATILE (exp))
1782 warning_with_file_and_line (emit_filename, emit_lineno,
1783 "value computed is not used");
1788 /* Clear out the memory of the last expression evaluated. */
1796 /* Begin a statement which will return a value.
1797 Return the RTL_EXPR for this statement expr.
1798 The caller must save that value and pass it to expand_end_stmt_expr. */
1801 expand_start_stmt_expr ()
1806 /* When generating bytecode just note down the stack depth */
1807 if (output_bytecode)
1808 return (build_int_2 (stack_depth, 0));
1810 /* Make the RTL_EXPR node temporary, not momentary,
1811 so that rtl_expr_chain doesn't become garbage. */
1812 momentary = suspend_momentary ();
1813 t = make_node (RTL_EXPR);
1814 resume_momentary (momentary);
1815 start_sequence_for_rtl_expr (t);
1817 expr_stmts_for_value++;
1821 /* Restore the previous state at the end of a statement that returns a value.
1822 Returns a tree node representing the statement's value and the
1823 insns to compute the value.
1825 The nodes of that expression have been freed by now, so we cannot use them.
1826 But we don't want to do that anyway; the expression has already been
1827 evaluated and now we just want to use the value. So generate a RTL_EXPR
1828 with the proper type and RTL value.
1830 If the last substatement was not an expression,
1831 return something with type `void'. */
1834 expand_end_stmt_expr (t)
1837 if (output_bytecode)
1843 /* At this point, all expressions have been evaluated in order.
1844 However, all expression values have been popped when evaluated,
1845 which means we have to recover the last expression value. This is
1846 the last value removed by means of a `drop' instruction. Instead
1847 of adding code to inhibit dropping the last expression value, it
1848 is here recovered by undoing the `drop'. Since `drop' is
1849 equivalent to `adjustackSI [1]', it can be undone with `adjstackSI
1852 bc_adjust_stack (-1);
1854 if (!last_expr_type)
1855 last_expr_type = void_type_node;
1857 t = make_node (RTL_EXPR);
1858 TREE_TYPE (t) = last_expr_type;
1859 RTL_EXPR_RTL (t) = NULL;
1860 RTL_EXPR_SEQUENCE (t) = NULL;
1862 /* Don't consider deleting this expr or containing exprs at tree level. */
1863 TREE_THIS_VOLATILE (t) = 1;
1871 if (last_expr_type == 0)
1873 last_expr_type = void_type_node;
1874 last_expr_value = const0_rtx;
1876 else if (last_expr_value == 0)
1877 /* There are some cases where this can happen, such as when the
1878 statement is void type. */
1879 last_expr_value = const0_rtx;
1880 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
1881 /* Remove any possible QUEUED. */
1882 last_expr_value = protect_from_queue (last_expr_value, 0);
1886 TREE_TYPE (t) = last_expr_type;
1887 RTL_EXPR_RTL (t) = last_expr_value;
1888 RTL_EXPR_SEQUENCE (t) = get_insns ();
1890 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
1894 /* Don't consider deleting this expr or containing exprs at tree level. */
1895 TREE_SIDE_EFFECTS (t) = 1;
1896 /* Propagate volatility of the actual RTL expr. */
1897 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
1900 expr_stmts_for_value--;
1905 /* Generate RTL for the start of an if-then. COND is the expression
1906 whose truth should be tested.
1908 If EXITFLAG is nonzero, this conditional is visible to
1909 `exit_something'. */
1912 expand_start_cond (cond, exitflag)
1916 struct nesting *thiscond = ALLOC_NESTING ();
1918 /* Make an entry on cond_stack for the cond we are entering. */
1920 thiscond->next = cond_stack;
1921 thiscond->all = nesting_stack;
1922 thiscond->depth = ++nesting_depth;
1923 thiscond->data.cond.next_label = gen_label_rtx ();
1924 /* Before we encounter an `else', we don't need a separate exit label
1925 unless there are supposed to be exit statements
1926 to exit this conditional. */
1927 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
1928 thiscond->data.cond.endif_label = thiscond->exit_label;
1929 cond_stack = thiscond;
1930 nesting_stack = thiscond;
1932 if (output_bytecode)
1933 bc_expand_start_cond (cond, exitflag);
1935 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
1938 /* Generate RTL between then-clause and the elseif-clause
1939 of an if-then-elseif-.... */
1942 expand_start_elseif (cond)
1945 if (cond_stack->data.cond.endif_label == 0)
1946 cond_stack->data.cond.endif_label = gen_label_rtx ();
1947 emit_jump (cond_stack->data.cond.endif_label);
1948 emit_label (cond_stack->data.cond.next_label);
1949 cond_stack->data.cond.next_label = gen_label_rtx ();
1950 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1953 /* Generate RTL between the then-clause and the else-clause
1954 of an if-then-else. */
1957 expand_start_else ()
1959 if (cond_stack->data.cond.endif_label == 0)
1960 cond_stack->data.cond.endif_label = gen_label_rtx ();
1962 if (output_bytecode)
1964 bc_expand_start_else ();
1968 emit_jump (cond_stack->data.cond.endif_label);
1969 emit_label (cond_stack->data.cond.next_label);
1970 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
1973 /* After calling expand_start_else, turn this "else" into an "else if"
1974 by providing another condition. */
1977 expand_elseif (cond)
1980 cond_stack->data.cond.next_label = gen_label_rtx ();
1981 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1984 /* Generate RTL for the end of an if-then.
1985 Pop the record for it off of cond_stack. */
1990 struct nesting *thiscond = cond_stack;
1992 if (output_bytecode)
1993 bc_expand_end_cond ();
1996 do_pending_stack_adjust ();
1997 if (thiscond->data.cond.next_label)
1998 emit_label (thiscond->data.cond.next_label);
1999 if (thiscond->data.cond.endif_label)
2000 emit_label (thiscond->data.cond.endif_label);
2003 POPSTACK (cond_stack);
2008 /* Generate code for the start of an if-then. COND is the expression
2009 whose truth is to be tested; if EXITFLAG is nonzero this conditional
2010 is to be visible to exit_something. It is assumed that the caller
2011 has pushed the previous context on the cond stack. */
2014 bc_expand_start_cond (cond, exitflag)
2018 struct nesting *thiscond = cond_stack;
2020 thiscond->data.case_stmt.nominal_type = cond;
2022 thiscond->exit_label = gen_label_rtx ();
2023 bc_expand_expr (cond);
2024 bc_emit_bytecode (xjumpifnot);
2025 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscond->exit_label));
2027 #ifdef DEBUG_PRINT_CODE
2028 fputc ('\n', stderr);
2032 /* Generate the label for the end of an if with
2036 bc_expand_end_cond ()
2038 struct nesting *thiscond = cond_stack;
2040 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscond->exit_label));
2043 /* Generate code for the start of the else- clause of
2047 bc_expand_start_else ()
2049 struct nesting *thiscond = cond_stack;
2051 thiscond->data.cond.endif_label = thiscond->exit_label;
2052 thiscond->exit_label = gen_label_rtx ();
2053 bc_emit_bytecode (jump);
2054 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscond->exit_label));
2056 #ifdef DEBUG_PRINT_CODE
2057 fputc ('\n', stderr);
2060 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscond->data.cond.endif_label));
2063 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2064 loop should be exited by `exit_something'. This is a loop for which
2065 `expand_continue' will jump to the top of the loop.
2067 Make an entry on loop_stack to record the labels associated with
2071 expand_start_loop (exit_flag)
2074 register struct nesting *thisloop = ALLOC_NESTING ();
2076 /* Make an entry on loop_stack for the loop we are entering. */
2078 thisloop->next = loop_stack;
2079 thisloop->all = nesting_stack;
2080 thisloop->depth = ++nesting_depth;
2081 thisloop->data.loop.start_label = gen_label_rtx ();
2082 thisloop->data.loop.end_label = gen_label_rtx ();
2083 thisloop->data.loop.alt_end_label = 0;
2084 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2085 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2086 loop_stack = thisloop;
2087 nesting_stack = thisloop;
2089 if (output_bytecode)
2091 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisloop->data.loop.start_label));
2095 do_pending_stack_adjust ();
2097 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
2098 emit_label (thisloop->data.loop.start_label);
2103 /* Like expand_start_loop but for a loop where the continuation point
2104 (for expand_continue_loop) will be specified explicitly. */
2107 expand_start_loop_continue_elsewhere (exit_flag)
2110 struct nesting *thisloop = expand_start_loop (exit_flag);
2111 loop_stack->data.loop.continue_label = gen_label_rtx ();
2115 /* Specify the continuation point for a loop started with
2116 expand_start_loop_continue_elsewhere.
2117 Use this at the point in the code to which a continue statement
2121 expand_loop_continue_here ()
2123 if (output_bytecode)
2125 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (loop_stack->data.loop.continue_label));
2128 do_pending_stack_adjust ();
2129 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
2130 emit_label (loop_stack->data.loop.continue_label);
2136 bc_expand_end_loop ()
2138 struct nesting *thisloop = loop_stack;
2140 bc_emit_bytecode (jump);
2141 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thisloop->data.loop.start_label));
2143 #ifdef DEBUG_PRINT_CODE
2144 fputc ('\n', stderr);
2147 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisloop->exit_label));
2148 POPSTACK (loop_stack);
2153 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2154 Pop the block off of loop_stack. */
2160 register rtx start_label;
2161 rtx last_test_insn = 0;
2164 if (output_bytecode)
2166 bc_expand_end_loop ();
2170 insn = get_last_insn ();
2171 start_label = loop_stack->data.loop.start_label;
2173 /* Mark the continue-point at the top of the loop if none elsewhere. */
2174 if (start_label == loop_stack->data.loop.continue_label)
2175 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2177 do_pending_stack_adjust ();
2179 /* If optimizing, perhaps reorder the loop. If the loop
2180 starts with a conditional exit, roll that to the end
2181 where it will optimize together with the jump back.
2183 We look for the last conditional branch to the exit that we encounter
2184 before hitting 30 insns or a CALL_INSN. If we see an unconditional
2185 branch to the exit first, use it.
2187 We must also stop at NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes
2188 because moving them is not valid. */
2192 ! (GET_CODE (insn) == JUMP_INSN
2193 && GET_CODE (PATTERN (insn)) == SET
2194 && SET_DEST (PATTERN (insn)) == pc_rtx
2195 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
2197 /* Scan insns from the top of the loop looking for a qualified
2198 conditional exit. */
2199 for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
2200 insn = NEXT_INSN (insn))
2202 if (GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == CODE_LABEL)
2205 if (GET_CODE (insn) == NOTE
2206 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2207 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2210 if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2213 if (last_test_insn && num_insns > 30)
2216 if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == SET
2217 && SET_DEST (PATTERN (insn)) == pc_rtx
2218 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE
2219 && ((GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == LABEL_REF
2220 && ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
2221 == loop_stack->data.loop.end_label)
2222 || (XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
2223 == loop_stack->data.loop.alt_end_label)))
2224 || (GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 2)) == LABEL_REF
2225 && ((XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
2226 == loop_stack->data.loop.end_label)
2227 || (XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
2228 == loop_stack->data.loop.alt_end_label)))))
2229 last_test_insn = insn;
2231 if (last_test_insn == 0 && GET_CODE (insn) == JUMP_INSN
2232 && GET_CODE (PATTERN (insn)) == SET
2233 && SET_DEST (PATTERN (insn)) == pc_rtx
2234 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF
2235 && ((XEXP (SET_SRC (PATTERN (insn)), 0)
2236 == loop_stack->data.loop.end_label)
2237 || (XEXP (SET_SRC (PATTERN (insn)), 0)
2238 == loop_stack->data.loop.alt_end_label)))
2239 /* Include BARRIER. */
2240 last_test_insn = NEXT_INSN (insn);
2243 if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2245 /* We found one. Move everything from there up
2246 to the end of the loop, and add a jump into the loop
2247 to jump to there. */
2248 register rtx newstart_label = gen_label_rtx ();
2249 register rtx start_move = start_label;
2251 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2252 then we want to move this note also. */
2253 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2254 && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2255 == NOTE_INSN_LOOP_CONT))
2256 start_move = PREV_INSN (start_move);
2258 emit_label_after (newstart_label, PREV_INSN (start_move));
2259 reorder_insns (start_move, last_test_insn, get_last_insn ());
2260 emit_jump_insn_after (gen_jump (start_label),
2261 PREV_INSN (newstart_label));
2262 emit_barrier_after (PREV_INSN (newstart_label));
2263 start_label = newstart_label;
2267 emit_jump (start_label);
2268 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
2269 emit_label (loop_stack->data.loop.end_label);
2271 POPSTACK (loop_stack);
2276 /* Generate a jump to the current loop's continue-point.
2277 This is usually the top of the loop, but may be specified
2278 explicitly elsewhere. If not currently inside a loop,
2279 return 0 and do nothing; caller will print an error message. */
2282 expand_continue_loop (whichloop)
2283 struct nesting *whichloop;
2287 whichloop = loop_stack;
2290 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2295 /* Generate a jump to exit the current loop. If not currently inside a loop,
2296 return 0 and do nothing; caller will print an error message. */
2299 expand_exit_loop (whichloop)
2300 struct nesting *whichloop;
2304 whichloop = loop_stack;
2307 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2311 /* Generate a conditional jump to exit the current loop if COND
2312 evaluates to zero. If not currently inside a loop,
2313 return 0 and do nothing; caller will print an error message. */
2316 expand_exit_loop_if_false (whichloop, cond)
2317 struct nesting *whichloop;
2322 whichloop = loop_stack;
2325 if (output_bytecode)
2327 bc_expand_expr (cond);
2328 bc_expand_goto_internal (xjumpifnot,
2329 BYTECODE_BC_LABEL (whichloop->exit_label),
2334 /* In order to handle fixups, we actually create a conditional jump
2335 around a unconditional branch to exit the loop. If fixups are
2336 necessary, they go before the unconditional branch. */
2338 rtx label = gen_label_rtx ();
2341 do_jump (cond, NULL_RTX, label);
2342 last_insn = get_last_insn ();
2343 if (GET_CODE (last_insn) == CODE_LABEL)
2344 whichloop->data.loop.alt_end_label = last_insn;
2345 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2353 /* Return non-zero if we should preserve sub-expressions as separate
2354 pseudos. We never do so if we aren't optimizing. We always do so
2355 if -fexpensive-optimizations.
2357 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2358 the loop may still be a small one. */
2361 preserve_subexpressions_p ()
2365 if (flag_expensive_optimizations)
2368 if (optimize == 0 || loop_stack == 0)
2371 insn = get_last_insn_anywhere ();
2374 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2375 < n_non_fixed_regs * 3));
2379 /* Generate a jump to exit the current loop, conditional, binding contour
2380 or case statement. Not all such constructs are visible to this function,
2381 only those started with EXIT_FLAG nonzero. Individual languages use
2382 the EXIT_FLAG parameter to control which kinds of constructs you can
2385 If not currently inside anything that can be exited,
2386 return 0 and do nothing; caller will print an error message. */
2389 expand_exit_something ()
2393 for (n = nesting_stack; n; n = n->all)
2394 if (n->exit_label != 0)
2396 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2403 /* Generate RTL to return from the current function, with no value.
2404 (That is, we do not do anything about returning any value.) */
2407 expand_null_return ()
2409 struct nesting *block = block_stack;
2412 if (output_bytecode)
2414 bc_emit_instruction (ret);
2418 /* Does any pending block have cleanups? */
2420 while (block && block->data.block.cleanups == 0)
2421 block = block->next;
2423 /* If yes, use a goto to return, since that runs cleanups. */
2425 expand_null_return_1 (last_insn, block != 0);
2428 /* Generate RTL to return from the current function, with value VAL. */
2431 expand_value_return (val)
2434 struct nesting *block = block_stack;
2435 rtx last_insn = get_last_insn ();
2436 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2438 /* Copy the value to the return location
2439 unless it's already there. */
2441 if (return_reg != val)
2443 #ifdef PROMOTE_FUNCTION_RETURN
2444 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2445 int unsignedp = TREE_UNSIGNED (type);
2446 enum machine_mode mode
2447 = promote_mode (type, DECL_MODE (DECL_RESULT (current_function_decl)),
2450 if (GET_MODE (val) != VOIDmode && GET_MODE (val) != mode)
2451 convert_move (return_reg, val, unsignedp);
2454 emit_move_insn (return_reg, val);
2456 if (GET_CODE (return_reg) == REG
2457 && REGNO (return_reg) < FIRST_PSEUDO_REGISTER)
2458 emit_insn (gen_rtx (USE, VOIDmode, return_reg));
2460 /* Does any pending block have cleanups? */
2462 while (block && block->data.block.cleanups == 0)
2463 block = block->next;
2465 /* If yes, use a goto to return, since that runs cleanups.
2466 Use LAST_INSN to put cleanups *before* the move insn emitted above. */
2468 expand_null_return_1 (last_insn, block != 0);
2471 /* Output a return with no value. If LAST_INSN is nonzero,
2472 pretend that the return takes place after LAST_INSN.
2473 If USE_GOTO is nonzero then don't use a return instruction;
2474 go to the return label instead. This causes any cleanups
2475 of pending blocks to be executed normally. */
2478 expand_null_return_1 (last_insn, use_goto)
2482 rtx end_label = cleanup_label ? cleanup_label : return_label;
2484 clear_pending_stack_adjust ();
2485 do_pending_stack_adjust ();
2488 /* PCC-struct return always uses an epilogue. */
2489 if (current_function_returns_pcc_struct || use_goto)
2492 end_label = return_label = gen_label_rtx ();
2493 expand_goto_internal (NULL_TREE, end_label, last_insn);
2497 /* Otherwise output a simple return-insn if one is available,
2498 unless it won't do the job. */
2500 if (HAVE_return && use_goto == 0 && cleanup_label == 0)
2502 emit_jump_insn (gen_return ());
2508 /* Otherwise jump to the epilogue. */
2509 expand_goto_internal (NULL_TREE, end_label, last_insn);
2512 /* Generate RTL to evaluate the expression RETVAL and return it
2513 from the current function. */
2516 expand_return (retval)
2519 /* If there are any cleanups to be performed, then they will
2520 be inserted following LAST_INSN. It is desirable
2521 that the last_insn, for such purposes, should be the
2522 last insn before computing the return value. Otherwise, cleanups
2523 which call functions can clobber the return value. */
2524 /* ??? rms: I think that is erroneous, because in C++ it would
2525 run destructors on variables that might be used in the subsequent
2526 computation of the return value. */
2528 register rtx val = 0;
2532 struct nesting *block;
2534 /* Bytecode returns are quite simple, just leave the result on the
2535 arithmetic stack. */
2536 if (output_bytecode)
2538 bc_expand_expr (retval);
2539 bc_emit_instruction (ret);
2543 /* If function wants no value, give it none. */
2544 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2546 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2548 expand_null_return ();
2552 /* Are any cleanups needed? E.g. C++ destructors to be run? */
2553 /* This is not sufficient. We also need to watch for cleanups of the
2554 expression we are about to expand. Unfortunately, we cannot know
2555 if it has cleanups until we expand it, and we want to change how we
2556 expand it depending upon if we need cleanups. We can't win. */
2558 cleanups = any_pending_cleanups (1);
2563 if (TREE_CODE (retval) == RESULT_DECL)
2564 retval_rhs = retval;
2565 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2566 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2567 retval_rhs = TREE_OPERAND (retval, 1);
2568 else if (TREE_TYPE (retval) == void_type_node)
2569 /* Recognize tail-recursive call to void function. */
2570 retval_rhs = retval;
2572 retval_rhs = NULL_TREE;
2574 /* Only use `last_insn' if there are cleanups which must be run. */
2575 if (cleanups || cleanup_label != 0)
2576 last_insn = get_last_insn ();
2578 /* Distribute return down conditional expr if either of the sides
2579 may involve tail recursion (see test below). This enhances the number
2580 of tail recursions we see. Don't do this always since it can produce
2581 sub-optimal code in some cases and we distribute assignments into
2582 conditional expressions when it would help. */
2584 if (optimize && retval_rhs != 0
2585 && frame_offset == 0
2586 && TREE_CODE (retval_rhs) == COND_EXPR
2587 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
2588 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
2590 rtx label = gen_label_rtx ();
2593 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
2594 expr = build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2595 DECL_RESULT (current_function_decl),
2596 TREE_OPERAND (retval_rhs, 1));
2597 TREE_SIDE_EFFECTS (expr) = 1;
2598 expand_return (expr);
2601 expr = build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2602 DECL_RESULT (current_function_decl),
2603 TREE_OPERAND (retval_rhs, 2));
2604 TREE_SIDE_EFFECTS (expr) = 1;
2605 expand_return (expr);
2609 /* For tail-recursive call to current function,
2610 just jump back to the beginning.
2611 It's unsafe if any auto variable in this function
2612 has its address taken; for simplicity,
2613 require stack frame to be empty. */
2614 if (optimize && retval_rhs != 0
2615 && frame_offset == 0
2616 && TREE_CODE (retval_rhs) == CALL_EXPR
2617 && TREE_CODE (TREE_OPERAND (retval_rhs, 0)) == ADDR_EXPR
2618 && TREE_OPERAND (TREE_OPERAND (retval_rhs, 0), 0) == current_function_decl
2619 /* Finish checking validity, and if valid emit code
2620 to set the argument variables for the new call. */
2621 && tail_recursion_args (TREE_OPERAND (retval_rhs, 1),
2622 DECL_ARGUMENTS (current_function_decl)))
2624 if (tail_recursion_label == 0)
2626 tail_recursion_label = gen_label_rtx ();
2627 emit_label_after (tail_recursion_label,
2628 tail_recursion_reentry);
2631 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
2636 /* This optimization is safe if there are local cleanups
2637 because expand_null_return takes care of them.
2638 ??? I think it should also be safe when there is a cleanup label,
2639 because expand_null_return takes care of them, too.
2640 Any reason why not? */
2641 if (HAVE_return && cleanup_label == 0
2642 && ! current_function_returns_pcc_struct
2643 && BRANCH_COST <= 1)
2645 /* If this is return x == y; then generate
2646 if (x == y) return 1; else return 0;
2647 if we can do it with explicit return insns and
2648 branches are cheap. */
2650 switch (TREE_CODE (retval_rhs))
2658 case TRUTH_ANDIF_EXPR:
2659 case TRUTH_ORIF_EXPR:
2660 case TRUTH_AND_EXPR:
2662 case TRUTH_NOT_EXPR:
2663 case TRUTH_XOR_EXPR:
2664 op0 = gen_label_rtx ();
2665 jumpifnot (retval_rhs, op0);
2666 expand_value_return (const1_rtx);
2668 expand_value_return (const0_rtx);
2672 #endif /* HAVE_return */
2674 /* If the result is an aggregate that is being returned in one (or more)
2675 registers, load the registers here. The compiler currently can't handle
2676 copying a BLKmode value into registers. We could put this code in a
2677 more general area (for use by everyone instead of just function
2678 call/return), but until this feature is generally usable it is kept here
2679 (and in expand_call). */
2682 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
2683 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2686 int big_endian_correction = 0;
2687 int bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2688 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2689 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
2690 rtx result_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2691 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2692 enum machine_mode tmpmode;
2694 /* Structures smaller than a word are aligned to the least significant
2695 byte (to the right). On a BYTES_BIG_ENDIAN machine, this means we
2696 must skip the empty high order bytes when calculating the bit
2698 if (BYTES_BIG_ENDIAN && bytes < UNITS_PER_WORD)
2699 big_endian_correction = (BITS_PER_WORD - (bytes * BITS_PER_UNIT));
2701 for (i = 0; i < n_regs; i++)
2703 rtx reg = gen_reg_rtx (word_mode);
2704 rtx word = operand_subword_force (result_val, i, BLKmode);
2705 int bitsize = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)),BITS_PER_WORD);
2708 result_pseudos[i] = reg;
2710 /* Clobber REG and move each partword into it. Ensure we don't
2711 go past the end of the structure. Note that the loop below
2712 works because we've already verified that padding and
2713 endianness are compatable. */
2714 emit_insn (gen_rtx (CLOBBER, VOIDmode, reg));
2717 bitpos < BITS_PER_WORD && bytes > 0;
2718 bitpos += bitsize, bytes -= bitsize / BITS_PER_UNIT)
2720 int xbitpos = bitpos + big_endian_correction;
2722 store_bit_field (reg, bitsize, xbitpos, word_mode,
2723 extract_bit_field (word, bitsize, bitpos, 1,
2724 NULL_RTX, word_mode,
2726 bitsize / BITS_PER_UNIT,
2728 bitsize / BITS_PER_UNIT, BITS_PER_WORD);
2732 /* Now that the value is in pseudos, copy it to the result reg(s). */
2735 for (i = 0; i < n_regs; i++)
2736 emit_move_insn (gen_rtx (REG, word_mode, REGNO (result_reg) + i),
2739 /* Find the smallest integer mode large enough to hold the
2740 entire structure and use that mode instead of BLKmode
2741 on the USE insn for the return register. */
2742 bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
2743 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
2744 tmpmode != MAX_MACHINE_MODE;
2745 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
2747 /* Have we found a large enough mode? */
2748 if (GET_MODE_SIZE (tmpmode) >= bytes)
2752 /* No suitable mode found. */
2753 if (tmpmode == MAX_MACHINE_MODE)
2756 PUT_MODE (result_reg, tmpmode);
2758 expand_value_return (result_reg);
2762 && TREE_TYPE (retval_rhs) != void_type_node
2763 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2765 /* Calculate the return value into a pseudo reg. */
2766 val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2768 /* All temporaries have now been used. */
2770 /* Return the calculated value, doing cleanups first. */
2771 expand_value_return (val);
2775 /* No cleanups or no hard reg used;
2776 calculate value into hard return reg. */
2777 expand_expr (retval, const0_rtx, VOIDmode, 0);
2780 expand_value_return (DECL_RTL (DECL_RESULT (current_function_decl)));
2784 /* Return 1 if the end of the generated RTX is not a barrier.
2785 This means code already compiled can drop through. */
2788 drop_through_at_end_p ()
2790 rtx insn = get_last_insn ();
2791 while (insn && GET_CODE (insn) == NOTE)
2792 insn = PREV_INSN (insn);
2793 return insn && GET_CODE (insn) != BARRIER;
2796 /* Emit code to alter this function's formal parms for a tail-recursive call.
2797 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
2798 FORMALS is the chain of decls of formals.
2799 Return 1 if this can be done;
2800 otherwise return 0 and do not emit any code. */
2803 tail_recursion_args (actuals, formals)
2804 tree actuals, formals;
2806 register tree a = actuals, f = formals;
2808 register rtx *argvec;
2810 /* Check that number and types of actuals are compatible
2811 with the formals. This is not always true in valid C code.
2812 Also check that no formal needs to be addressable
2813 and that all formals are scalars. */
2815 /* Also count the args. */
2817 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
2819 if (TREE_TYPE (TREE_VALUE (a)) != TREE_TYPE (f))
2821 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
2824 if (a != 0 || f != 0)
2827 /* Compute all the actuals. */
2829 argvec = (rtx *) alloca (i * sizeof (rtx));
2831 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2832 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
2834 /* Find which actual values refer to current values of previous formals.
2835 Copy each of them now, before any formal is changed. */
2837 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2841 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
2842 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
2843 { copy = 1; break; }
2845 argvec[i] = copy_to_reg (argvec[i]);
2848 /* Store the values of the actuals into the formals. */
2850 for (f = formals, a = actuals, i = 0; f;
2851 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
2853 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
2854 emit_move_insn (DECL_RTL (f), argvec[i]);
2856 convert_move (DECL_RTL (f), argvec[i],
2857 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
2864 /* Generate the RTL code for entering a binding contour.
2865 The variables are declared one by one, by calls to `expand_decl'.
2867 EXIT_FLAG is nonzero if this construct should be visible to
2868 `exit_something'. */
2871 expand_start_bindings (exit_flag)
2874 struct nesting *thisblock = ALLOC_NESTING ();
2875 rtx note = output_bytecode ? 0 : emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
2877 /* Make an entry on block_stack for the block we are entering. */
2879 thisblock->next = block_stack;
2880 thisblock->all = nesting_stack;
2881 thisblock->depth = ++nesting_depth;
2882 thisblock->data.block.stack_level = 0;
2883 thisblock->data.block.cleanups = 0;
2884 thisblock->data.block.function_call_count = 0;
2888 if (block_stack->data.block.cleanups == NULL_TREE
2889 && (block_stack->data.block.outer_cleanups == NULL_TREE
2890 || block_stack->data.block.outer_cleanups == empty_cleanup_list))
2891 thisblock->data.block.outer_cleanups = empty_cleanup_list;
2893 thisblock->data.block.outer_cleanups
2894 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2895 block_stack->data.block.outer_cleanups);
2898 thisblock->data.block.outer_cleanups = 0;
2902 && !(block_stack->data.block.cleanups == NULL_TREE
2903 && block_stack->data.block.outer_cleanups == NULL_TREE))
2904 thisblock->data.block.outer_cleanups
2905 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2906 block_stack->data.block.outer_cleanups);
2908 thisblock->data.block.outer_cleanups = 0;
2910 thisblock->data.block.label_chain = 0;
2911 thisblock->data.block.innermost_stack_block = stack_block_stack;
2912 thisblock->data.block.first_insn = note;
2913 thisblock->data.block.block_start_count = ++block_start_count;
2914 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
2915 block_stack = thisblock;
2916 nesting_stack = thisblock;
2918 if (!output_bytecode)
2920 /* Make a new level for allocating stack slots. */
2925 /* Given a pointer to a BLOCK node, save a pointer to the most recently
2926 generated NOTE_INSN_BLOCK_END in the BLOCK_END_NOTE field of the given
2930 remember_end_note (block)
2931 register tree block;
2933 BLOCK_END_NOTE (block) = last_block_end_note;
2934 last_block_end_note = NULL_RTX;
2937 /* Generate RTL code to terminate a binding contour.
2938 VARS is the chain of VAR_DECL nodes
2939 for the variables bound in this contour.
2940 MARK_ENDS is nonzero if we should put a note at the beginning
2941 and end of this binding contour.
2943 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
2944 (That is true automatically if the contour has a saved stack level.) */
2947 expand_end_bindings (vars, mark_ends, dont_jump_in)
2952 register struct nesting *thisblock = block_stack;
2955 if (output_bytecode)
2957 bc_expand_end_bindings (vars, mark_ends, dont_jump_in);
2962 for (decl = vars; decl; decl = TREE_CHAIN (decl))
2963 if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL
2964 && ! DECL_IN_SYSTEM_HEADER (decl))
2965 warning_with_decl (decl, "unused variable `%s'");
2967 if (thisblock->exit_label)
2969 do_pending_stack_adjust ();
2970 emit_label (thisblock->exit_label);
2973 /* If necessary, make a handler for nonlocal gotos taking
2974 place in the function calls in this block. */
2975 if (function_call_count != thisblock->data.block.function_call_count
2977 /* Make handler for outermost block
2978 if there were any nonlocal gotos to this function. */
2979 && (thisblock->next == 0 ? current_function_has_nonlocal_label
2980 /* Make handler for inner block if it has something
2981 special to do when you jump out of it. */
2982 : (thisblock->data.block.cleanups != 0
2983 || thisblock->data.block.stack_level != 0)))
2986 rtx afterward = gen_label_rtx ();
2987 rtx handler_label = gen_label_rtx ();
2988 rtx save_receiver = gen_reg_rtx (Pmode);
2991 /* Don't let jump_optimize delete the handler. */
2992 LABEL_PRESERVE_P (handler_label) = 1;
2994 /* Record the handler address in the stack slot for that purpose,
2995 during this block, saving and restoring the outer value. */
2996 if (thisblock->next != 0)
2998 emit_move_insn (nonlocal_goto_handler_slot, save_receiver);
3001 emit_move_insn (save_receiver, nonlocal_goto_handler_slot);
3002 insns = get_insns ();
3004 emit_insns_before (insns, thisblock->data.block.first_insn);
3008 emit_move_insn (nonlocal_goto_handler_slot,
3009 gen_rtx (LABEL_REF, Pmode, handler_label));
3010 insns = get_insns ();
3012 emit_insns_before (insns, thisblock->data.block.first_insn);
3014 /* Jump around the handler; it runs only when specially invoked. */
3015 emit_jump (afterward);
3016 emit_label (handler_label);
3018 #ifdef HAVE_nonlocal_goto
3019 if (! HAVE_nonlocal_goto)
3021 /* First adjust our frame pointer to its actual value. It was
3022 previously set to the start of the virtual area corresponding to
3023 the stacked variables when we branched here and now needs to be
3024 adjusted to the actual hardware fp value.
3026 Assignments are to virtual registers are converted by
3027 instantiate_virtual_regs into the corresponding assignment
3028 to the underlying register (fp in this case) that makes
3029 the original assignment true.
3030 So the following insn will actually be
3031 decrementing fp by STARTING_FRAME_OFFSET. */
3032 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3034 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3035 if (fixed_regs[ARG_POINTER_REGNUM])
3037 #ifdef ELIMINABLE_REGS
3038 /* If the argument pointer can be eliminated in favor of the
3039 frame pointer, we don't need to restore it. We assume here
3040 that if such an elimination is present, it can always be used.
3041 This is the case on all known machines; if we don't make this
3042 assumption, we do unnecessary saving on many machines. */
3043 static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
3046 for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
3047 if (elim_regs[i].from == ARG_POINTER_REGNUM
3048 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3051 if (i == sizeof elim_regs / sizeof elim_regs [0])
3054 /* Now restore our arg pointer from the address at which it
3055 was saved in our stack frame.
3056 If there hasn't be space allocated for it yet, make
3058 if (arg_pointer_save_area == 0)
3059 arg_pointer_save_area
3060 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
3061 emit_move_insn (virtual_incoming_args_rtx,
3062 /* We need a pseudo here, or else
3063 instantiate_virtual_regs_1 complains. */
3064 copy_to_reg (arg_pointer_save_area));
3069 /* The handler expects the desired label address in the static chain
3070 register. It tests the address and does an appropriate jump
3071 to whatever label is desired. */
3072 for (link = nonlocal_labels; link; link = TREE_CHAIN (link))
3073 /* Skip any labels we shouldn't be able to jump to from here. */
3074 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3076 rtx not_this = gen_label_rtx ();
3077 rtx this = gen_label_rtx ();
3078 do_jump_if_equal (static_chain_rtx,
3079 gen_rtx (LABEL_REF, Pmode, DECL_RTL (TREE_VALUE (link))),
3081 emit_jump (not_this);
3083 expand_goto (TREE_VALUE (link));
3084 emit_label (not_this);
3086 /* If label is not recognized, abort. */
3087 emit_library_call (gen_rtx (SYMBOL_REF, Pmode, "abort"), 0,
3089 emit_label (afterward);
3092 /* Don't allow jumping into a block that has cleanups or a stack level. */
3094 || thisblock->data.block.stack_level != 0
3095 || thisblock->data.block.cleanups != 0)
3097 struct label_chain *chain;
3099 /* Any labels in this block are no longer valid to go to.
3100 Mark them to cause an error message. */
3101 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3103 DECL_TOO_LATE (chain->label) = 1;
3104 /* If any goto without a fixup came to this label,
3105 that must be an error, because gotos without fixups
3106 come from outside all saved stack-levels and all cleanups. */
3107 if (TREE_ADDRESSABLE (chain->label))
3108 error_with_decl (chain->label,
3109 "label `%s' used before containing binding contour");
3113 /* Restore stack level in effect before the block
3114 (only if variable-size objects allocated). */
3115 /* Perform any cleanups associated with the block. */
3117 if (thisblock->data.block.stack_level != 0
3118 || thisblock->data.block.cleanups != 0)
3120 /* Only clean up here if this point can actually be reached. */
3121 int reachable = GET_CODE (get_last_insn ()) != BARRIER;
3123 /* Don't let cleanups affect ({...}) constructs. */
3124 int old_expr_stmts_for_value = expr_stmts_for_value;
3125 rtx old_last_expr_value = last_expr_value;
3126 tree old_last_expr_type = last_expr_type;
3127 expr_stmts_for_value = 0;
3129 /* Do the cleanups. */
3130 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3132 do_pending_stack_adjust ();
3134 expr_stmts_for_value = old_expr_stmts_for_value;
3135 last_expr_value = old_last_expr_value;
3136 last_expr_type = old_last_expr_type;
3138 /* Restore the stack level. */
3140 if (reachable && thisblock->data.block.stack_level != 0)
3142 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3143 thisblock->data.block.stack_level, NULL_RTX);
3144 if (nonlocal_goto_handler_slot != 0)
3145 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3149 /* Any gotos out of this block must also do these things.
3150 Also report any gotos with fixups that came to labels in this
3152 fixup_gotos (thisblock,
3153 thisblock->data.block.stack_level,
3154 thisblock->data.block.cleanups,
3155 thisblock->data.block.first_insn,
3159 /* Mark the beginning and end of the scope if requested.
3160 We do this now, after running cleanups on the variables
3161 just going out of scope, so they are in scope for their cleanups. */
3164 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
3166 /* Get rid of the beginning-mark if we don't make an end-mark. */
3167 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3169 /* If doing stupid register allocation, make sure lives of all
3170 register variables declared here extend thru end of scope. */
3173 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3175 rtx rtl = DECL_RTL (decl);
3176 if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
3180 /* Restore block_stack level for containing block. */
3182 stack_block_stack = thisblock->data.block.innermost_stack_block;
3183 POPSTACK (block_stack);
3185 /* Pop the stack slot nesting and free any slots at this level. */
3190 /* End a binding contour.
3191 VARS is the chain of VAR_DECL nodes for the variables bound
3192 in this contour. MARK_ENDS is nonzer if we should put a note
3193 at the beginning and end of this binding contour.
3194 DONT_JUMP_IN is nonzero if it is not valid to jump into this
3198 bc_expand_end_bindings (vars, mark_ends, dont_jump_in)
3203 struct nesting *thisbind = nesting_stack;
3207 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3208 if (! TREE_USED (TREE_VALUE (decl)) && TREE_CODE (TREE_VALUE (decl)) == VAR_DECL)
3209 warning_with_decl (decl, "unused variable `%s'");
3211 if (thisbind->exit_label)
3212 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thisbind->exit_label));
3214 /* Pop block/bindings off stack */
3215 POPSTACK (block_stack);
3218 /* Generate RTL for the automatic variable declaration DECL.
3219 (Other kinds of declarations are simply ignored if seen here.)
3220 CLEANUP is an expression to be executed at exit from this binding contour;
3221 for example, in C++, it might call the destructor for this variable.
3223 If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
3224 either before or after calling `expand_decl' but before compiling
3225 any subsequent expressions. This is because CLEANUP may be expanded
3226 more than once, on different branches of execution.
3227 For the same reason, CLEANUP may not contain a CALL_EXPR
3228 except as its topmost node--else `preexpand_calls' would get confused.
3230 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3231 that is not associated with any particular variable.
3233 There is no special support here for C++ constructors.
3234 They should be handled by the proper code in DECL_INITIAL. */
3240 struct nesting *thisblock = block_stack;
3243 if (output_bytecode)
3245 bc_expand_decl (decl, 0);
3249 type = TREE_TYPE (decl);
3251 /* Only automatic variables need any expansion done.
3252 Static and external variables, and external functions,
3253 will be handled by `assemble_variable' (called from finish_decl).
3254 TYPE_DECL and CONST_DECL require nothing.
3255 PARM_DECLs are handled in `assign_parms'. */
3257 if (TREE_CODE (decl) != VAR_DECL)
3259 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3262 /* Create the RTL representation for the variable. */
3264 if (type == error_mark_node)
3265 DECL_RTL (decl) = gen_rtx (MEM, BLKmode, const0_rtx);
3266 else if (DECL_SIZE (decl) == 0)
3267 /* Variable with incomplete type. */
3269 if (DECL_INITIAL (decl) == 0)
3270 /* Error message was already done; now avoid a crash. */
3271 DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
3273 /* An initializer is going to decide the size of this array.
3274 Until we know the size, represent its address with a reg. */
3275 DECL_RTL (decl) = gen_rtx (MEM, BLKmode, gen_reg_rtx (Pmode));
3276 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (type);
3278 else if (DECL_MODE (decl) != BLKmode
3279 /* If -ffloat-store, don't put explicit float vars
3281 && !(flag_float_store
3282 && TREE_CODE (type) == REAL_TYPE)
3283 && ! TREE_THIS_VOLATILE (decl)
3284 && ! TREE_ADDRESSABLE (decl)
3285 && (DECL_REGISTER (decl) || ! obey_regdecls))
3287 /* Automatic variable that can go in a register. */
3288 int unsignedp = TREE_UNSIGNED (type);
3289 enum machine_mode reg_mode
3290 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3292 if (TREE_CODE (type) == COMPLEX_TYPE)
3294 rtx realpart, imagpart;
3295 enum machine_mode partmode = TYPE_MODE (TREE_TYPE (type));
3297 /* For a complex type variable, make a CONCAT of two pseudos
3298 so that the real and imaginary parts
3299 can be allocated separately. */
3300 realpart = gen_reg_rtx (partmode);
3301 REG_USERVAR_P (realpart) = 1;
3302 imagpart = gen_reg_rtx (partmode);
3303 REG_USERVAR_P (imagpart) = 1;
3304 DECL_RTL (decl) = gen_rtx (CONCAT, reg_mode, realpart, imagpart);
3308 DECL_RTL (decl) = gen_reg_rtx (reg_mode);
3309 if (TREE_CODE (type) == POINTER_TYPE)
3310 mark_reg_pointer (DECL_RTL (decl));
3311 REG_USERVAR_P (DECL_RTL (decl)) = 1;
3314 else if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST)
3316 /* Variable of fixed size that goes on the stack. */
3320 /* If we previously made RTL for this decl, it must be an array
3321 whose size was determined by the initializer.
3322 The old address was a register; set that register now
3323 to the proper address. */
3324 if (DECL_RTL (decl) != 0)
3326 if (GET_CODE (DECL_RTL (decl)) != MEM
3327 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3329 oldaddr = XEXP (DECL_RTL (decl), 0);
3333 = assign_stack_temp (DECL_MODE (decl),
3334 ((TREE_INT_CST_LOW (DECL_SIZE (decl))
3335 + BITS_PER_UNIT - 1)
3338 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (TREE_TYPE (decl));
3340 /* Set alignment we actually gave this decl. */
3341 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3342 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3346 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3347 if (addr != oldaddr)
3348 emit_move_insn (oldaddr, addr);
3351 /* If this is a memory ref that contains aggregate components,
3352 mark it as such for cse and loop optimize. */
3353 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (TREE_TYPE (decl));
3355 /* If this is in memory because of -ffloat-store,
3356 set the volatile bit, to prevent optimizations from
3357 undoing the effects. */
3358 if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
3359 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3363 /* Dynamic-size object: must push space on the stack. */
3367 /* Record the stack pointer on entry to block, if have
3368 not already done so. */
3369 if (thisblock->data.block.stack_level == 0)
3371 do_pending_stack_adjust ();
3372 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3373 &thisblock->data.block.stack_level,
3374 thisblock->data.block.first_insn);
3375 stack_block_stack = thisblock;
3378 /* Compute the variable's size, in bytes. */
3379 size = expand_expr (size_binop (CEIL_DIV_EXPR,
3381 size_int (BITS_PER_UNIT)),
3382 NULL_RTX, VOIDmode, 0);
3385 /* Allocate space on the stack for the variable. */
3386 address = allocate_dynamic_stack_space (size, NULL_RTX,
3389 /* Reference the variable indirect through that rtx. */
3390 DECL_RTL (decl) = gen_rtx (MEM, DECL_MODE (decl), address);
3392 /* If this is a memory ref that contains aggregate components,
3393 mark it as such for cse and loop optimize. */
3394 MEM_IN_STRUCT_P (DECL_RTL (decl)) = AGGREGATE_TYPE_P (TREE_TYPE (decl));
3396 /* Indicate the alignment we actually gave this variable. */
3397 #ifdef STACK_BOUNDARY
3398 DECL_ALIGN (decl) = STACK_BOUNDARY;
3400 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3404 if (TREE_THIS_VOLATILE (decl))
3405 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3406 #if 0 /* A variable is not necessarily unchanging
3407 just because it is const. RTX_UNCHANGING_P
3408 means no change in the function,
3409 not merely no change in the variable's scope.
3410 It is correct to set RTX_UNCHANGING_P if the variable's scope
3411 is the whole function. There's no convenient way to test that. */
3412 if (TREE_READONLY (decl))
3413 RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
3416 /* If doing stupid register allocation, make sure life of any
3417 register variable starts here, at the start of its scope. */
3420 use_variable (DECL_RTL (decl));
3424 /* Generate code for the automatic variable declaration DECL. For
3425 most variables this just means we give it a stack offset. The
3426 compiler sometimes emits cleanups without variables and we will
3427 have to deal with those too. */
3430 bc_expand_decl (decl, cleanup)
3438 /* A cleanup with no variable. */
3445 /* Only auto variables need any work. */
3446 if (TREE_CODE (decl) != VAR_DECL || TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3449 type = TREE_TYPE (decl);
3451 if (type == error_mark_node)
3452 DECL_RTL (decl) = bc_gen_rtx ((char *) 0, 0, (struct bc_label *) 0);
3454 else if (DECL_SIZE (decl) == 0)
3456 /* Variable with incomplete type. The stack offset herein will be
3457 fixed later in expand_decl_init (). */
3458 DECL_RTL (decl) = bc_gen_rtx ((char *) 0, 0, (struct bc_label *) 0);
3460 else if (TREE_CONSTANT (DECL_SIZE (decl)))
3462 DECL_RTL (decl) = bc_allocate_local (TREE_INT_CST_LOW (DECL_SIZE (decl)) / BITS_PER_UNIT,
3466 DECL_RTL (decl) = bc_allocate_variable_array (DECL_SIZE (decl));
3469 /* Emit code to perform the initialization of a declaration DECL. */
3472 expand_decl_init (decl)
3475 int was_used = TREE_USED (decl);
3477 if (output_bytecode)
3479 bc_expand_decl_init (decl);
3483 /* If this is a CONST_DECL, we don't have to generate any code, but
3484 if DECL_INITIAL is a constant, call expand_expr to force TREE_CST_RTL
3485 to be set while in the obstack containing the constant. If we don't
3486 do this, we can lose if we have functions nested three deep and the middle
3487 function makes a CONST_DECL whose DECL_INITIAL is a STRING_CST while
3488 the innermost function is the first to expand that STRING_CST. */
3489 if (TREE_CODE (decl) == CONST_DECL)
3491 if (DECL_INITIAL (decl) && TREE_CONSTANT (DECL_INITIAL (decl)))
3492 expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
3493 EXPAND_INITIALIZER);
3497 if (TREE_STATIC (decl))
3500 /* Compute and store the initial value now. */
3502 if (DECL_INITIAL (decl) == error_mark_node)
3504 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3505 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3506 || code == POINTER_TYPE)
3507 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3511 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3513 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
3514 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
3518 /* Don't let the initialization count as "using" the variable. */
3519 TREE_USED (decl) = was_used;
3521 /* Free any temporaries we made while initializing the decl. */
3525 /* Expand initialization for variable-sized types. Allocate array
3526 using newlocalSI and set local variable, which is a pointer to the
3530 bc_expand_variable_local_init (decl)
3533 /* Evaluate size expression and coerce to SI */
3534 bc_expand_expr (DECL_SIZE (decl));
3536 /* Type sizes are always (?) of TREE_CODE INTEGER_CST, so
3537 no coercion is necessary (?) */
3539 /* emit_typecode_conversion (preferred_typecode (TYPE_MODE (DECL_SIZE (decl)),
3540 TREE_UNSIGNED (DECL_SIZE (decl))), SIcode); */
3542 /* Emit code to allocate array */
3543 bc_emit_instruction (newlocalSI);
3545 /* Store array pointer in local variable. This is the only instance
3546 where we actually want the address of the pointer to the
3547 variable-size block, rather than the pointer itself. We avoid
3548 using expand_address() since that would cause the pointer to be
3549 pushed rather than its address. Hence the hard-coded reference;
3550 notice also that the variable is always local (no global
3551 variable-size type variables). */
3553 bc_load_localaddr (DECL_RTL (decl));
3554 bc_emit_instruction (storeP);
3558 /* Emit code to initialize a declaration. */
3561 bc_expand_decl_init (decl)
3564 int org_stack_depth;
3566 /* Statical initializers are handled elsewhere */
3568 if (TREE_STATIC (decl))
3571 /* Memory original stack depth */
3572 org_stack_depth = stack_depth;
3574 /* If the type is variable-size, we first create its space (we ASSUME
3575 it CAN'T be static). We do this regardless of whether there's an
3576 initializer assignment or not. */
3578 if (TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
3579 bc_expand_variable_local_init (decl);
3581 /* Expand initializer assignment */
3582 if (DECL_INITIAL (decl) == error_mark_node)
3584 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3586 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3587 || code == POINTER_TYPE)
3589 expand_assignment (TREE_TYPE (decl), decl, 0, 0);
3591 else if (DECL_INITIAL (decl))
3592 expand_assignment (TREE_TYPE (decl), decl, 0, 0);
3594 /* Restore stack depth */
3595 if (org_stack_depth > stack_depth)
3598 bc_adjust_stack (stack_depth - org_stack_depth);
3602 /* CLEANUP is an expression to be executed at exit from this binding contour;
3603 for example, in C++, it might call the destructor for this variable.
3605 If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
3606 either before or after calling `expand_decl' but before compiling
3607 any subsequent expressions. This is because CLEANUP may be expanded
3608 more than once, on different branches of execution.
3609 For the same reason, CLEANUP may not contain a CALL_EXPR
3610 except as its topmost node--else `preexpand_calls' would get confused.
3612 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3613 that is not associated with any particular variable. */
3616 expand_decl_cleanup (decl, cleanup)
3619 struct nesting *thisblock = block_stack;
3621 /* Error if we are not in any block. */
3625 /* Record the cleanup if there is one. */
3629 thisblock->data.block.cleanups
3630 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3631 /* If this block has a cleanup, it belongs in stack_block_stack. */
3632 stack_block_stack = thisblock;
3633 (*interim_eh_hook) (NULL_TREE);
3638 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3639 DECL_ELTS is the list of elements that belong to DECL's type.
3640 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3643 expand_anon_union_decl (decl, cleanup, decl_elts)
3644 tree decl, cleanup, decl_elts;
3646 struct nesting *thisblock = block_stack;
3649 expand_decl (decl, cleanup);
3650 x = DECL_RTL (decl);
3654 tree decl_elt = TREE_VALUE (decl_elts);
3655 tree cleanup_elt = TREE_PURPOSE (decl_elts);
3656 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3658 /* Propagate the union's alignment to the elements. */
3659 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
3661 /* If the element has BLKmode and the union doesn't, the union is
3662 aligned such that the element doesn't need to have BLKmode, so
3663 change the element's mode to the appropriate one for its size. */
3664 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
3665 DECL_MODE (decl_elt) = mode
3666 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl_elt)),
3669 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3670 instead create a new MEM rtx with the proper mode. */
3671 if (GET_CODE (x) == MEM)
3673 if (mode == GET_MODE (x))
3674 DECL_RTL (decl_elt) = x;
3677 DECL_RTL (decl_elt) = gen_rtx (MEM, mode, copy_rtx (XEXP (x, 0)));
3678 MEM_IN_STRUCT_P (DECL_RTL (decl_elt)) = MEM_IN_STRUCT_P (x);
3679 RTX_UNCHANGING_P (DECL_RTL (decl_elt)) = RTX_UNCHANGING_P (x);
3682 else if (GET_CODE (x) == REG)
3684 if (mode == GET_MODE (x))
3685 DECL_RTL (decl_elt) = x;
3687 DECL_RTL (decl_elt) = gen_rtx (SUBREG, mode, x, 0);
3692 /* Record the cleanup if there is one. */
3695 thisblock->data.block.cleanups
3696 = temp_tree_cons (decl_elt, cleanup_elt,
3697 thisblock->data.block.cleanups);
3699 decl_elts = TREE_CHAIN (decl_elts);
3703 /* Expand a list of cleanups LIST.
3704 Elements may be expressions or may be nested lists.
3706 If DONT_DO is nonnull, then any list-element
3707 whose TREE_PURPOSE matches DONT_DO is omitted.
3708 This is sometimes used to avoid a cleanup associated with
3709 a value that is being returned out of the scope.
3711 If IN_FIXUP is non-zero, we are generating this cleanup for a fixup
3712 goto and handle protection regions specially in that case.
3714 If REACHABLE, we emit code, otherwise just inform the exception handling
3715 code about this finalization. */
3718 expand_cleanups (list, dont_do, in_fixup, reachable)
3725 for (tail = list; tail; tail = TREE_CHAIN (tail))
3726 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
3728 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
3729 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
3733 (*interim_eh_hook) (TREE_VALUE (tail));
3737 /* Cleanups may be run multiple times. For example,
3738 when exiting a binding contour, we expand the
3739 cleanups associated with that contour. When a goto
3740 within that binding contour has a target outside that
3741 contour, it will expand all cleanups from its scope to
3742 the target. Though the cleanups are expanded multiple
3743 times, the control paths are non-overlapping so the
3744 cleanups will not be executed twice. */
3745 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3752 /* Move all cleanups from the current block_stack
3753 to the containing block_stack, where they are assumed to
3754 have been created. If anything can cause a temporary to
3755 be created, but not expanded for more than one level of
3756 block_stacks, then this code will have to change. */
3761 struct nesting *block = block_stack;
3762 struct nesting *outer = block->next;
3764 outer->data.block.cleanups
3765 = chainon (block->data.block.cleanups,
3766 outer->data.block.cleanups);
3767 block->data.block.cleanups = 0;
3771 last_cleanup_this_contour ()
3773 if (block_stack == 0)
3776 return block_stack->data.block.cleanups;
3779 /* Return 1 if there are any pending cleanups at this point.
3780 If THIS_CONTOUR is nonzero, check the current contour as well.
3781 Otherwise, look only at the contours that enclose this one. */
3784 any_pending_cleanups (this_contour)
3787 struct nesting *block;
3789 if (block_stack == 0)
3792 if (this_contour && block_stack->data.block.cleanups != NULL)
3794 if (block_stack->data.block.cleanups == 0
3795 && (block_stack->data.block.outer_cleanups == 0
3797 || block_stack->data.block.outer_cleanups == empty_cleanup_list
3802 for (block = block_stack->next; block; block = block->next)
3803 if (block->data.block.cleanups != 0)
3809 /* Enter a case (Pascal) or switch (C) statement.
3810 Push a block onto case_stack and nesting_stack
3811 to accumulate the case-labels that are seen
3812 and to record the labels generated for the statement.
3814 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
3815 Otherwise, this construct is transparent for `exit_something'.
3817 EXPR is the index-expression to be dispatched on.
3818 TYPE is its nominal type. We could simply convert EXPR to this type,
3819 but instead we take short cuts. */
3822 expand_start_case (exit_flag, expr, type, printname)
3828 register struct nesting *thiscase = ALLOC_NESTING ();
3830 /* Make an entry on case_stack for the case we are entering. */
3832 thiscase->next = case_stack;
3833 thiscase->all = nesting_stack;
3834 thiscase->depth = ++nesting_depth;
3835 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
3836 thiscase->data.case_stmt.case_list = 0;
3837 thiscase->data.case_stmt.index_expr = expr;
3838 thiscase->data.case_stmt.nominal_type = type;
3839 thiscase->data.case_stmt.default_label = 0;
3840 thiscase->data.case_stmt.num_ranges = 0;
3841 thiscase->data.case_stmt.printname = printname;
3842 thiscase->data.case_stmt.seenlabel = 0;
3843 case_stack = thiscase;
3844 nesting_stack = thiscase;
3846 if (output_bytecode)
3848 bc_expand_start_case (thiscase, expr, type, printname);
3852 do_pending_stack_adjust ();
3854 /* Make sure case_stmt.start points to something that won't
3855 need any transformation before expand_end_case. */
3856 if (GET_CODE (get_last_insn ()) != NOTE)
3857 emit_note (NULL_PTR, NOTE_INSN_DELETED);
3859 thiscase->data.case_stmt.start = get_last_insn ();
3863 /* Enter a case statement. It is assumed that the caller has pushed
3864 the current context onto the case stack. */
3867 bc_expand_start_case (thiscase, expr, type, printname)
3868 struct nesting *thiscase;
3873 bc_expand_expr (expr);
3874 bc_expand_conversion (TREE_TYPE (expr), type);
3876 /* For cases, the skip is a place we jump to that's emitted after
3877 the size of the jump table is known. */
3879 thiscase->data.case_stmt.skip_label = gen_label_rtx ();
3880 bc_emit_bytecode (jump);
3881 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->data.case_stmt.skip_label));
3883 #ifdef DEBUG_PRINT_CODE
3884 fputc ('\n', stderr);
3889 /* Start a "dummy case statement" within which case labels are invalid
3890 and are not connected to any larger real case statement.
3891 This can be used if you don't want to let a case statement jump
3892 into the middle of certain kinds of constructs. */
3895 expand_start_case_dummy ()
3897 register struct nesting *thiscase = ALLOC_NESTING ();
3899 /* Make an entry on case_stack for the dummy. */
3901 thiscase->next = case_stack;
3902 thiscase->all = nesting_stack;
3903 thiscase->depth = ++nesting_depth;
3904 thiscase->exit_label = 0;
3905 thiscase->data.case_stmt.case_list = 0;
3906 thiscase->data.case_stmt.start = 0;
3907 thiscase->data.case_stmt.nominal_type = 0;
3908 thiscase->data.case_stmt.default_label = 0;
3909 thiscase->data.case_stmt.num_ranges = 0;
3910 case_stack = thiscase;
3911 nesting_stack = thiscase;
3914 /* End a dummy case statement. */
3917 expand_end_case_dummy ()
3919 POPSTACK (case_stack);
3922 /* Return the data type of the index-expression
3923 of the innermost case statement, or null if none. */
3926 case_index_expr_type ()
3929 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
3933 /* Accumulate one case or default label inside a case or switch statement.
3934 VALUE is the value of the case (a null pointer, for a default label).
3935 The function CONVERTER, when applied to arguments T and V,
3936 converts the value V to the type T.
3938 If not currently inside a case or switch statement, return 1 and do
3939 nothing. The caller will print a language-specific error message.
3940 If VALUE is a duplicate or overlaps, return 2 and do nothing
3941 except store the (first) duplicate node in *DUPLICATE.
3942 If VALUE is out of range, return 3 and do nothing.
3943 If we are jumping into the scope of a cleaup or var-sized array, return 5.
3944 Return 0 on success.
3946 Extended to handle range statements. */
3949 pushcase (value, converter, label, duplicate)
3950 register tree value;
3951 tree (*converter) PROTO((tree, tree));
3952 register tree label;
3955 register struct case_node **l;
3956 register struct case_node *n;
3960 if (output_bytecode)
3961 return bc_pushcase (value, label);
3963 /* Fail if not inside a real case statement. */
3964 if (! (case_stack && case_stack->data.case_stmt.start))
3967 if (stack_block_stack
3968 && stack_block_stack->depth > case_stack->depth)
3971 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3972 nominal_type = case_stack->data.case_stmt.nominal_type;
3974 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3975 if (index_type == error_mark_node)
3978 /* Convert VALUE to the type in which the comparisons are nominally done. */
3980 value = (*converter) (nominal_type, value);
3982 /* If this is the first label, warn if any insns have been emitted. */
3983 if (case_stack->data.case_stmt.seenlabel == 0)
3986 for (insn = case_stack->data.case_stmt.start;
3988 insn = NEXT_INSN (insn))
3990 if (GET_CODE (insn) == CODE_LABEL)
3992 if (GET_CODE (insn) != NOTE
3993 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
3995 warning ("unreachable code at beginning of %s",
3996 case_stack->data.case_stmt.printname);
4001 case_stack->data.case_stmt.seenlabel = 1;
4003 /* Fail if this value is out of range for the actual type of the index
4004 (which may be narrower than NOMINAL_TYPE). */
4005 if (value != 0 && ! int_fits_type_p (value, index_type))
4008 /* Fail if this is a duplicate or overlaps another entry. */
4011 if (case_stack->data.case_stmt.default_label != 0)
4013 *duplicate = case_stack->data.case_stmt.default_label;
4016 case_stack->data.case_stmt.default_label = label;
4020 /* Find the elt in the chain before which to insert the new value,
4021 to keep the chain sorted in increasing order.
4022 But report an error if this element is a duplicate. */
4023 for (l = &case_stack->data.case_stmt.case_list;
4024 /* Keep going past elements distinctly less than VALUE. */
4025 *l != 0 && tree_int_cst_lt ((*l)->high, value);
4030 /* Element we will insert before must be distinctly greater;
4031 overlap means error. */
4032 if (! tree_int_cst_lt (value, (*l)->low))
4034 *duplicate = (*l)->code_label;
4039 /* Add this label to the chain, and succeed.
4040 Copy VALUE so it is on temporary rather than momentary
4041 obstack and will thus survive till the end of the case statement. */
4042 n = (struct case_node *) oballoc (sizeof (struct case_node));
4045 n->high = n->low = copy_node (value);
4046 n->code_label = label;
4050 expand_label (label);
4054 /* Like pushcase but this case applies to all values
4055 between VALUE1 and VALUE2 (inclusive).
4056 The return value is the same as that of pushcase
4057 but there is one additional error code:
4058 4 means the specified range was empty. */
4061 pushcase_range (value1, value2, converter, label, duplicate)
4062 register tree value1, value2;
4063 tree (*converter) PROTO((tree, tree));
4064 register tree label;
4067 register struct case_node **l;
4068 register struct case_node *n;
4072 /* Fail if not inside a real case statement. */
4073 if (! (case_stack && case_stack->data.case_stmt.start))
4076 if (stack_block_stack
4077 && stack_block_stack->depth > case_stack->depth)
4080 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4081 nominal_type = case_stack->data.case_stmt.nominal_type;
4083 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4084 if (index_type == error_mark_node)
4087 /* If this is the first label, warn if any insns have been emitted. */
4088 if (case_stack->data.case_stmt.seenlabel == 0)
4091 for (insn = case_stack->data.case_stmt.start;
4093 insn = NEXT_INSN (insn))
4095 if (GET_CODE (insn) == CODE_LABEL)
4097 if (GET_CODE (insn) != NOTE
4098 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4100 warning ("unreachable code at beginning of %s",
4101 case_stack->data.case_stmt.printname);
4106 case_stack->data.case_stmt.seenlabel = 1;
4108 /* Convert VALUEs to type in which the comparisons are nominally done. */
4109 if (value1 == 0) /* Negative infinity. */
4110 value1 = TYPE_MIN_VALUE(index_type);
4111 value1 = (*converter) (nominal_type, value1);
4113 if (value2 == 0) /* Positive infinity. */
4114 value2 = TYPE_MAX_VALUE(index_type);
4115 value2 = (*converter) (nominal_type, value2);
4117 /* Fail if these values are out of range. */
4118 if (! int_fits_type_p (value1, index_type))
4121 if (! int_fits_type_p (value2, index_type))
4124 /* Fail if the range is empty. */
4125 if (tree_int_cst_lt (value2, value1))
4128 /* If the bounds are equal, turn this into the one-value case. */
4129 if (tree_int_cst_equal (value1, value2))
4130 return pushcase (value1, converter, label, duplicate);
4132 /* Find the elt in the chain before which to insert the new value,
4133 to keep the chain sorted in increasing order.
4134 But report an error if this element is a duplicate. */
4135 for (l = &case_stack->data.case_stmt.case_list;
4136 /* Keep going past elements distinctly less than this range. */
4137 *l != 0 && tree_int_cst_lt ((*l)->high, value1);
4142 /* Element we will insert before must be distinctly greater;
4143 overlap means error. */
4144 if (! tree_int_cst_lt (value2, (*l)->low))
4146 *duplicate = (*l)->code_label;
4151 /* Add this label to the chain, and succeed.
4152 Copy VALUE1, VALUE2 so they are on temporary rather than momentary
4153 obstack and will thus survive till the end of the case statement. */
4155 n = (struct case_node *) oballoc (sizeof (struct case_node));
4158 n->low = copy_node (value1);
4159 n->high = copy_node (value2);
4160 n->code_label = label;
4163 expand_label (label);
4165 case_stack->data.case_stmt.num_ranges++;
4171 /* Accumulate one case or default label; VALUE is the value of the
4172 case, or nil for a default label. If not currently inside a case,
4173 return 1 and do nothing. If VALUE is a duplicate or overlaps, return
4174 2 and do nothing. If VALUE is out of range, return 3 and do nothing.
4175 Return 0 on success. This function is a leftover from the earlier
4176 bytecode compiler, which was based on gcc 1.37. It should be
4177 merged into pushcase. */
4180 bc_pushcase (value, label)
4184 struct nesting *thiscase = case_stack;
4185 struct case_node *case_label, *new_label;
4190 /* Fail if duplicate, overlap, or out of type range. */
4193 value = convert (thiscase->data.case_stmt.nominal_type, value);
4194 if (! int_fits_type_p (value, thiscase->data.case_stmt.nominal_type))
4197 for (case_label = thiscase->data.case_stmt.case_list;
4198 case_label->left; case_label = case_label->left)
4199 if (! tree_int_cst_lt (case_label->left->high, value))
4202 if (case_label != thiscase->data.case_stmt.case_list
4203 && ! tree_int_cst_lt (case_label->high, value)
4204 || case_label->left && ! tree_int_cst_lt (value, case_label->left->low))
4207 new_label = (struct case_node *) oballoc (sizeof (struct case_node));
4208 new_label->low = new_label->high = copy_node (value);
4209 new_label->code_label = label;
4210 new_label->left = case_label->left;
4212 case_label->left = new_label;
4213 thiscase->data.case_stmt.num_ranges++;
4217 if (thiscase->data.case_stmt.default_label)
4219 thiscase->data.case_stmt.default_label = label;
4222 expand_label (label);
4226 /* Returns the number of possible values of TYPE.
4227 Returns -1 if the number is unknown or variable.
4228 Returns -2 if the number does not fit in a HOST_WIDE_INT.
4229 Sets *SPARENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4230 do not increase monotonically (there may be duplicates);
4231 to 1 if the values increase monotonically, but not always by 1;
4232 otherwise sets it to 0. */
4235 all_cases_count (type, spareness)
4239 HOST_WIDE_INT count, count_high = 0;
4242 switch (TREE_CODE (type))
4249 count = 1 << BITS_PER_UNIT;
4253 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4254 || TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST)
4259 = TREE_INT_CST_LOW (TYPE_MAX_VALUE (type))
4260 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + 1
4261 but with overflow checking. */
4262 tree mint = TYPE_MIN_VALUE (type);
4263 tree maxt = TYPE_MAX_VALUE (type);
4264 HOST_WIDE_INT lo, hi;
4265 neg_double(TREE_INT_CST_LOW (mint), TREE_INT_CST_HIGH (mint),
4267 add_double(TREE_INT_CST_LOW (maxt), TREE_INT_CST_HIGH (maxt),
4269 add_double (lo, hi, 1, 0, &lo, &hi);
4270 if (hi != 0 || lo < 0)
4277 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4279 if (TREE_CODE (TYPE_MIN_VALUE (type)) != INTEGER_CST
4280 || TREE_CODE (TREE_VALUE (t)) != INTEGER_CST
4281 || TREE_INT_CST_LOW (TYPE_MIN_VALUE (type)) + count
4282 != TREE_INT_CST_LOW (TREE_VALUE (t)))
4286 if (*spareness == 1)
4288 tree prev = TREE_VALUE (TYPE_VALUES (type));
4289 for (t = TYPE_VALUES (type); t = TREE_CHAIN (t), t != NULL_TREE; )
4291 if (! tree_int_cst_lt (prev, TREE_VALUE (t)))
4296 prev = TREE_VALUE (t);
4305 #define BITARRAY_TEST(ARRAY, INDEX) \
4306 ((ARRAY)[(unsigned)(INDEX) / HOST_BITS_PER_CHAR]\
4307 & (1 << ((unsigned)(INDEX) % HOST_BITS_PER_CHAR)))
4308 #define BITARRAY_SET(ARRAY, INDEX) \
4309 ((ARRAY)[(unsigned)(INDEX) / HOST_BITS_PER_CHAR]\
4310 |= 1 << ((unsigned)(INDEX) % HOST_BITS_PER_CHAR))
4312 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4313 with the case values we have seen, assuming the case expression
4315 SPARSENESS is as determined by all_cases_count.
4317 The time needed is propotional to COUNT, unless
4318 SPARSENESS is 2, in which case quadratic time is needed. */
4321 mark_seen_cases (type, cases_seen, count, sparseness)
4323 unsigned char *cases_seen;
4329 tree next_node_to_try = NULL_TREE;
4330 long next_node_offset = 0;
4332 register struct case_node *n;
4333 tree val = make_node (INTEGER_CST);
4334 TREE_TYPE (val) = type;
4335 for (n = case_stack->data.case_stmt.case_list; n;
4338 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
4339 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
4340 while ( ! tree_int_cst_lt (n->high, val))
4342 /* Calculate (into xlo) the "offset" of the integer (val).
4343 The element with lowest value has offset 0, the next smallest
4344 element has offset 1, etc. */
4346 HOST_WIDE_INT xlo, xhi;
4348 if (sparseness == 2)
4350 /* This less efficient loop is only needed to handle
4351 duplicate case values (multiple enum constants
4352 with the same value). */
4353 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
4354 t = TREE_CHAIN (t), xlo++)
4356 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4357 BITARRAY_SET (cases_seen, xlo);
4362 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
4364 /* The TYPE_VALUES will be in increasing order, so
4365 starting searching where we last ended. */
4366 t = next_node_to_try;
4367 xlo = next_node_offset;
4373 t = TYPE_VALUES (type);
4376 if (tree_int_cst_equal (val, TREE_VALUE (t)))
4378 next_node_to_try = TREE_CHAIN (t);
4379 next_node_offset = xlo + 1;
4384 if (t == next_node_to_try)
4390 t = TYPE_MIN_VALUE (type);
4392 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
4396 add_double (xlo, xhi,
4397 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4401 if (xhi == 0 && xlo >= 0 && xlo < count)
4402 BITARRAY_SET (cases_seen, xlo);
4404 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
4406 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
4411 /* Called when the index of a switch statement is an enumerated type
4412 and there is no default label.
4414 Checks that all enumeration literals are covered by the case
4415 expressions of a switch. Also, warn if there are any extra
4416 switch cases that are *not* elements of the enumerated type.
4418 If all enumeration literals were covered by the case expressions,
4419 turn one of the expressions into the default expression since it should
4420 not be possible to fall through such a switch. */
4423 check_for_full_enumeration_handling (type)
4426 register struct case_node *n;
4427 register struct case_node **l;
4428 register tree chain;
4431 /* True iff the selector type is a numbered set mode. */
4434 /* The number of possible selector values. */
4437 /* For each possible selector value. a one iff it has been matched
4438 by a case value alternative. */
4439 unsigned char *cases_seen;
4441 /* The allocated size of cases_seen, in chars. */
4445 if (output_bytecode)
4447 bc_check_for_full_enumeration_handling (type);
4454 size = all_cases_count (type, &sparseness);
4455 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
4457 if (size > 0 && size < 600000
4458 /* We deliberately use malloc here - not xmalloc. */
4459 && (cases_seen = (unsigned char *) malloc (bytes_needed)) != NULL)
4462 tree v = TYPE_VALUES (type);
4463 bzero (cases_seen, bytes_needed);
4465 /* The time complexity of this code is normally O(N), where
4466 N being the number of members in the enumerated type.
4467 However, if type is a ENUMERAL_TYPE whose values do not
4468 increase monotonically, quadratic time may be needed. */
4470 mark_seen_cases (type, cases_seen, size, sparseness);
4472 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
4474 if (BITARRAY_TEST(cases_seen, i) == 0)
4475 warning ("enumeration value `%s' not handled in switch",
4476 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
4482 /* Now we go the other way around; we warn if there are case
4483 expressions that don't correspond to enumerators. This can
4484 occur since C and C++ don't enforce type-checking of
4485 assignments to enumeration variables. */
4488 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
4490 for (chain = TYPE_VALUES (type);
4491 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
4492 chain = TREE_CHAIN (chain))
4497 if (TYPE_NAME (type) == 0)
4498 warning ("case value `%d' not in enumerated type",
4499 TREE_INT_CST_LOW (n->low));
4501 warning ("case value `%d' not in enumerated type `%s'",
4502 TREE_INT_CST_LOW (n->low),
4503 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4506 : DECL_NAME (TYPE_NAME (type))));
4508 if (!tree_int_cst_equal (n->low, n->high))
4510 for (chain = TYPE_VALUES (type);
4511 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
4512 chain = TREE_CHAIN (chain))
4517 if (TYPE_NAME (type) == 0)
4518 warning ("case value `%d' not in enumerated type",
4519 TREE_INT_CST_LOW (n->high));
4521 warning ("case value `%d' not in enumerated type `%s'",
4522 TREE_INT_CST_LOW (n->high),
4523 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
4526 : DECL_NAME (TYPE_NAME (type))));
4532 /* ??? This optimization is disabled because it causes valid programs to
4533 fail. ANSI C does not guarantee that an expression with enum type
4534 will have a value that is the same as one of the enumation literals. */
4536 /* If all values were found as case labels, make one of them the default
4537 label. Thus, this switch will never fall through. We arbitrarily pick
4538 the last one to make the default since this is likely the most
4539 efficient choice. */
4543 for (l = &case_stack->data.case_stmt.case_list;
4548 case_stack->data.case_stmt.default_label = (*l)->code_label;
4555 /* Check that all enumeration literals are covered by the case
4556 expressions of a switch. Also warn if there are any cases
4557 that are not elements of the enumerated type. */
4560 bc_check_for_full_enumeration_handling (type)
4563 struct nesting *thiscase = case_stack;
4564 struct case_node *c;
4567 /* Check for enums not handled. */
4568 for (e = TYPE_VALUES (type); e; e = TREE_CHAIN (e))
4570 for (c = thiscase->data.case_stmt.case_list->left;
4571 c && tree_int_cst_lt (c->high, TREE_VALUE (e));
4574 if (! (c && tree_int_cst_equal (c->low, TREE_VALUE (e))))
4575 warning ("enumerated value `%s' not handled in switch",
4576 IDENTIFIER_POINTER (TREE_PURPOSE (e)));
4579 /* Check for cases not in the enumeration. */
4580 for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
4582 for (e = TYPE_VALUES (type);
4583 e && !tree_int_cst_equal (c->low, TREE_VALUE (e));
4587 warning ("case value `%d' not in enumerated type `%s'",
4588 TREE_INT_CST_LOW (c->low),
4589 IDENTIFIER_POINTER (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE
4591 : DECL_NAME (TYPE_NAME (type))));
4595 /* Terminate a case (Pascal) or switch (C) statement
4596 in which ORIG_INDEX is the expression to be tested.
4597 Generate the code to test it and jump to the right place. */
4600 expand_end_case (orig_index)
4603 tree minval, maxval, range, orig_minval;
4604 rtx default_label = 0;
4605 register struct case_node *n;
4613 register struct nesting *thiscase = case_stack;
4614 tree index_expr, index_type;
4617 if (output_bytecode)
4619 bc_expand_end_case (orig_index);
4623 table_label = gen_label_rtx ();
4624 index_expr = thiscase->data.case_stmt.index_expr;
4625 index_type = TREE_TYPE (index_expr);
4626 unsignedp = TREE_UNSIGNED (index_type);
4628 do_pending_stack_adjust ();
4630 /* An ERROR_MARK occurs for various reasons including invalid data type. */
4631 if (index_type != error_mark_node)
4633 /* If switch expression was an enumerated type, check that all
4634 enumeration literals are covered by the cases.
4635 No sense trying this if there's a default case, however. */
4637 if (!thiscase->data.case_stmt.default_label
4638 && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
4639 && TREE_CODE (index_expr) != INTEGER_CST)
4640 check_for_full_enumeration_handling (TREE_TYPE (orig_index));
4642 /* If this is the first label, warn if any insns have been emitted. */
4643 if (thiscase->data.case_stmt.seenlabel == 0)
4646 for (insn = get_last_insn ();
4647 insn != case_stack->data.case_stmt.start;
4648 insn = PREV_INSN (insn))
4649 if (GET_CODE (insn) != NOTE
4650 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn))!= USE))
4652 warning ("unreachable code at beginning of %s",
4653 case_stack->data.case_stmt.printname);
4658 /* If we don't have a default-label, create one here,
4659 after the body of the switch. */
4660 if (thiscase->data.case_stmt.default_label == 0)
4662 thiscase->data.case_stmt.default_label
4663 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
4664 expand_label (thiscase->data.case_stmt.default_label);
4666 default_label = label_rtx (thiscase->data.case_stmt.default_label);
4668 before_case = get_last_insn ();
4670 /* Simplify the case-list before we count it. */
4671 group_case_nodes (thiscase->data.case_stmt.case_list);
4673 /* Get upper and lower bounds of case values.
4674 Also convert all the case values to the index expr's data type. */
4677 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4679 /* Check low and high label values are integers. */
4680 if (TREE_CODE (n->low) != INTEGER_CST)
4682 if (TREE_CODE (n->high) != INTEGER_CST)
4685 n->low = convert (index_type, n->low);
4686 n->high = convert (index_type, n->high);
4688 /* Count the elements and track the largest and smallest
4689 of them (treating them as signed even if they are not). */
4697 if (INT_CST_LT (n->low, minval))
4699 if (INT_CST_LT (maxval, n->high))
4702 /* A range counts double, since it requires two compares. */
4703 if (! tree_int_cst_equal (n->low, n->high))
4707 orig_minval = minval;
4709 /* Compute span of values. */
4711 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
4715 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
4717 emit_jump (default_label);
4720 /* If range of values is much bigger than number of values,
4721 make a sequence of conditional branches instead of a dispatch.
4722 If the switch-index is a constant, do it this way
4723 because we can optimize it. */
4725 #ifndef CASE_VALUES_THRESHOLD
4727 #define CASE_VALUES_THRESHOLD (HAVE_casesi ? 4 : 5)
4729 /* If machine does not have a case insn that compares the
4730 bounds, this means extra overhead for dispatch tables
4731 which raises the threshold for using them. */
4732 #define CASE_VALUES_THRESHOLD 5
4733 #endif /* HAVE_casesi */
4734 #endif /* CASE_VALUES_THRESHOLD */
4736 else if (TREE_INT_CST_HIGH (range) != 0
4737 || count < CASE_VALUES_THRESHOLD
4738 || ((unsigned HOST_WIDE_INT) (TREE_INT_CST_LOW (range))
4740 || TREE_CODE (index_expr) == INTEGER_CST
4741 /* These will reduce to a constant. */
4742 || (TREE_CODE (index_expr) == CALL_EXPR
4743 && TREE_CODE (TREE_OPERAND (index_expr, 0)) == ADDR_EXPR
4744 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == FUNCTION_DECL
4745 && DECL_FUNCTION_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_CLASSIFY_TYPE)
4746 || (TREE_CODE (index_expr) == COMPOUND_EXPR
4747 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
4749 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4751 /* If the index is a short or char that we do not have
4752 an insn to handle comparisons directly, convert it to
4753 a full integer now, rather than letting each comparison
4754 generate the conversion. */
4756 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
4757 && (cmp_optab->handlers[(int) GET_MODE(index)].insn_code
4758 == CODE_FOR_nothing))
4760 enum machine_mode wider_mode;
4761 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
4762 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
4763 if (cmp_optab->handlers[(int) wider_mode].insn_code
4764 != CODE_FOR_nothing)
4766 index = convert_to_mode (wider_mode, index, unsignedp);
4772 do_pending_stack_adjust ();
4774 index = protect_from_queue (index, 0);
4775 if (GET_CODE (index) == MEM)
4776 index = copy_to_reg (index);
4777 if (GET_CODE (index) == CONST_INT
4778 || TREE_CODE (index_expr) == INTEGER_CST)
4780 /* Make a tree node with the proper constant value
4781 if we don't already have one. */
4782 if (TREE_CODE (index_expr) != INTEGER_CST)
4785 = build_int_2 (INTVAL (index),
4786 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
4787 index_expr = convert (index_type, index_expr);
4790 /* For constant index expressions we need only
4791 issue a unconditional branch to the appropriate
4792 target code. The job of removing any unreachable
4793 code is left to the optimisation phase if the
4794 "-O" option is specified. */
4795 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4796 if (! tree_int_cst_lt (index_expr, n->low)
4797 && ! tree_int_cst_lt (n->high, index_expr))
4801 emit_jump (label_rtx (n->code_label));
4803 emit_jump (default_label);
4807 /* If the index expression is not constant we generate
4808 a binary decision tree to select the appropriate
4809 target code. This is done as follows:
4811 The list of cases is rearranged into a binary tree,
4812 nearly optimal assuming equal probability for each case.
4814 The tree is transformed into RTL, eliminating
4815 redundant test conditions at the same time.
4817 If program flow could reach the end of the
4818 decision tree an unconditional jump to the
4819 default code is emitted. */
4822 = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
4823 && estimate_case_costs (thiscase->data.case_stmt.case_list));
4824 balance_case_nodes (&thiscase->data.case_stmt.case_list,
4826 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
4827 default_label, index_type);
4828 emit_jump_if_reachable (default_label);
4837 enum machine_mode index_mode = SImode;
4838 int index_bits = GET_MODE_BITSIZE (index_mode);
4840 enum machine_mode op_mode;
4842 /* Convert the index to SImode. */
4843 if (GET_MODE_BITSIZE (TYPE_MODE (index_type))
4844 > GET_MODE_BITSIZE (index_mode))
4846 enum machine_mode omode = TYPE_MODE (index_type);
4847 rtx rangertx = expand_expr (range, NULL_RTX, VOIDmode, 0);
4849 /* We must handle the endpoints in the original mode. */
4850 index_expr = build (MINUS_EXPR, index_type,
4851 index_expr, minval);
4852 minval = integer_zero_node;
4853 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4854 emit_cmp_insn (rangertx, index, LTU, NULL_RTX, omode, 1, 0);
4855 emit_jump_insn (gen_bltu (default_label));
4856 /* Now we can safely truncate. */
4857 index = convert_to_mode (index_mode, index, 0);
4861 if (TYPE_MODE (index_type) != index_mode)
4863 index_expr = convert (type_for_size (index_bits, 0),
4865 index_type = TREE_TYPE (index_expr);
4868 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4871 index = protect_from_queue (index, 0);
4872 do_pending_stack_adjust ();
4874 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][0];
4875 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][0])
4877 index = copy_to_mode_reg (op_mode, index);
4879 op1 = expand_expr (minval, NULL_RTX, VOIDmode, 0);
4881 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][1];
4882 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][1])
4884 op1 = copy_to_mode_reg (op_mode, op1);
4886 op2 = expand_expr (range, NULL_RTX, VOIDmode, 0);
4888 op_mode = insn_operand_mode[(int)CODE_FOR_casesi][2];
4889 if (! (*insn_operand_predicate[(int)CODE_FOR_casesi][2])
4891 op2 = copy_to_mode_reg (op_mode, op2);
4893 emit_jump_insn (gen_casesi (index, op1, op2,
4894 table_label, default_label));
4898 #ifdef HAVE_tablejump
4899 if (! win && HAVE_tablejump)
4901 index_expr = convert (thiscase->data.case_stmt.nominal_type,
4902 fold (build (MINUS_EXPR, index_type,
4903 index_expr, minval)));
4904 index_type = TREE_TYPE (index_expr);
4905 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
4907 index = protect_from_queue (index, 0);
4908 do_pending_stack_adjust ();
4910 do_tablejump (index, TYPE_MODE (index_type),
4911 expand_expr (range, NULL_RTX, VOIDmode, 0),
4912 table_label, default_label);
4919 /* Get table of labels to jump to, in order of case index. */
4921 ncases = TREE_INT_CST_LOW (range) + 1;
4922 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
4923 bzero ((char *) labelvec, ncases * sizeof (rtx));
4925 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
4927 register HOST_WIDE_INT i
4928 = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
4933 = gen_rtx (LABEL_REF, Pmode, label_rtx (n->code_label));
4934 if (i + TREE_INT_CST_LOW (orig_minval)
4935 == TREE_INT_CST_LOW (n->high))
4941 /* Fill in the gaps with the default. */
4942 for (i = 0; i < ncases; i++)
4943 if (labelvec[i] == 0)
4944 labelvec[i] = gen_rtx (LABEL_REF, Pmode, default_label);
4946 /* Output the table */
4947 emit_label (table_label);
4949 /* This would be a lot nicer if CASE_VECTOR_PC_RELATIVE
4950 were an expression, instead of an #ifdef/#ifndef. */
4952 #ifdef CASE_VECTOR_PC_RELATIVE
4956 emit_jump_insn (gen_rtx (ADDR_DIFF_VEC, CASE_VECTOR_MODE,
4957 gen_rtx (LABEL_REF, Pmode, table_label),
4958 gen_rtvec_v (ncases, labelvec)));
4960 emit_jump_insn (gen_rtx (ADDR_VEC, CASE_VECTOR_MODE,
4961 gen_rtvec_v (ncases, labelvec)));
4963 /* If the case insn drops through the table,
4964 after the table we must jump to the default-label.
4965 Otherwise record no drop-through after the table. */
4966 #ifdef CASE_DROPS_THROUGH
4967 emit_jump (default_label);
4973 before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
4974 reorder_insns (before_case, get_last_insn (),
4975 thiscase->data.case_stmt.start);
4978 if (thiscase->exit_label)
4979 emit_label (thiscase->exit_label);
4981 POPSTACK (case_stack);
4987 /* Terminate a case statement. EXPR is the original index
4991 bc_expand_end_case (expr)
4994 struct nesting *thiscase = case_stack;
4995 enum bytecode_opcode opcode;
4996 struct bc_label *jump_label;
4997 struct case_node *c;
4999 bc_emit_bytecode (jump);
5000 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->exit_label));
5002 #ifdef DEBUG_PRINT_CODE
5003 fputc ('\n', stderr);
5006 /* Now that the size of the jump table is known, emit the actual
5007 indexed jump instruction. */
5008 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscase->data.case_stmt.skip_label));
5010 opcode = TYPE_MODE (thiscase->data.case_stmt.nominal_type) == SImode
5011 ? TREE_UNSIGNED (thiscase->data.case_stmt.nominal_type) ? caseSU : caseSI
5012 : TREE_UNSIGNED (thiscase->data.case_stmt.nominal_type) ? caseDU : caseDI;
5014 bc_emit_bytecode (opcode);
5016 /* Now emit the case instructions literal arguments, in order.
5017 In addition to the value on the stack, it uses:
5018 1. The address of the jump table.
5019 2. The size of the jump table.
5020 3. The default label. */
5022 jump_label = bc_get_bytecode_label ();
5023 bc_emit_bytecode_labelref (jump_label);
5024 bc_emit_bytecode_const ((char *) &thiscase->data.case_stmt.num_ranges,
5025 sizeof thiscase->data.case_stmt.num_ranges);
5027 if (thiscase->data.case_stmt.default_label)
5028 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (thiscase->data.case_stmt.default_label)));
5030 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (thiscase->exit_label));
5032 /* Output the jump table. */
5034 bc_align_bytecode (3 /* PTR_ALIGN */);
5035 bc_emit_bytecode_labeldef (jump_label);
5037 if (TYPE_MODE (thiscase->data.case_stmt.nominal_type) == SImode)
5038 for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
5040 opcode = TREE_INT_CST_LOW (c->low);
5041 bc_emit_bytecode_const ((char *) &opcode, sizeof opcode);
5043 opcode = TREE_INT_CST_LOW (c->high);
5044 bc_emit_bytecode_const ((char *) &opcode, sizeof opcode);
5046 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (c->code_label)));
5049 if (TYPE_MODE (thiscase->data.case_stmt.nominal_type) == DImode)
5050 for (c = thiscase->data.case_stmt.case_list->left; c; c = c->left)
5052 bc_emit_bytecode_DI_const (c->low);
5053 bc_emit_bytecode_DI_const (c->high);
5055 bc_emit_bytecode_labelref (BYTECODE_BC_LABEL (DECL_RTL (c->code_label)));
5062 bc_emit_bytecode_labeldef (BYTECODE_BC_LABEL (thiscase->exit_label));
5064 /* Possibly issue enumeration warnings. */
5066 if (!thiscase->data.case_stmt.default_label
5067 && TREE_CODE (TREE_TYPE (expr)) == ENUMERAL_TYPE
5068 && TREE_CODE (expr) != INTEGER_CST
5070 check_for_full_enumeration_handling (TREE_TYPE (expr));
5073 #ifdef DEBUG_PRINT_CODE
5074 fputc ('\n', stderr);
5077 POPSTACK (case_stack);
5081 /* Return unique bytecode ID. */
5086 static int bc_uid = 0;
5091 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5094 do_jump_if_equal (op1, op2, label, unsignedp)
5095 rtx op1, op2, label;
5098 if (GET_CODE (op1) == CONST_INT
5099 && GET_CODE (op2) == CONST_INT)
5101 if (INTVAL (op1) == INTVAL (op2))
5106 enum machine_mode mode = GET_MODE (op1);
5107 if (mode == VOIDmode)
5108 mode = GET_MODE (op2);
5109 emit_cmp_insn (op1, op2, EQ, NULL_RTX, mode, unsignedp, 0);
5110 emit_jump_insn (gen_beq (label));
5114 /* Not all case values are encountered equally. This function
5115 uses a heuristic to weight case labels, in cases where that
5116 looks like a reasonable thing to do.
5118 Right now, all we try to guess is text, and we establish the
5121 chars above space: 16
5130 If we find any cases in the switch that are not either -1 or in the range
5131 of valid ASCII characters, or are control characters other than those
5132 commonly used with "\", don't treat this switch scanning text.
5134 Return 1 if these nodes are suitable for cost estimation, otherwise
5138 estimate_case_costs (node)
5141 tree min_ascii = build_int_2 (-1, -1);
5142 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5146 /* If we haven't already made the cost table, make it now. Note that the
5147 lower bound of the table is -1, not zero. */
5149 if (cost_table == NULL)
5151 cost_table = ((short *) xmalloc (129 * sizeof (short))) + 1;
5152 bzero ((char *) (cost_table - 1), 129 * sizeof (short));
5154 for (i = 0; i < 128; i++)
5158 else if (ispunct (i))
5160 else if (iscntrl (i))
5164 cost_table[' '] = 8;
5165 cost_table['\t'] = 4;
5166 cost_table['\0'] = 4;
5167 cost_table['\n'] = 2;
5168 cost_table['\f'] = 1;
5169 cost_table['\v'] = 1;
5170 cost_table['\b'] = 1;
5173 /* See if all the case expressions look like text. It is text if the
5174 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5175 as signed arithmetic since we don't want to ever access cost_table with a
5176 value less than -1. Also check that none of the constants in a range
5177 are strange control characters. */
5179 for (n = node; n; n = n->right)
5181 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5184 for (i = TREE_INT_CST_LOW (n->low); i <= TREE_INT_CST_LOW (n->high); i++)
5185 if (cost_table[i] < 0)
5189 /* All interesting values are within the range of interesting
5190 ASCII characters. */
5194 /* Scan an ordered list of case nodes
5195 combining those with consecutive values or ranges.
5197 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5200 group_case_nodes (head)
5203 case_node_ptr node = head;
5207 rtx lb = next_real_insn (label_rtx (node->code_label));
5208 case_node_ptr np = node;
5210 /* Try to group the successors of NODE with NODE. */
5211 while (((np = np->right) != 0)
5212 /* Do they jump to the same place? */
5213 && next_real_insn (label_rtx (np->code_label)) == lb
5214 /* Are their ranges consecutive? */
5215 && tree_int_cst_equal (np->low,
5216 fold (build (PLUS_EXPR,
5217 TREE_TYPE (node->high),
5220 /* An overflow is not consecutive. */
5221 && tree_int_cst_lt (node->high,
5222 fold (build (PLUS_EXPR,
5223 TREE_TYPE (node->high),
5225 integer_one_node))))
5227 node->high = np->high;
5229 /* NP is the first node after NODE which can't be grouped with it.
5230 Delete the nodes in between, and move on to that node. */
5236 /* Take an ordered list of case nodes
5237 and transform them into a near optimal binary tree,
5238 on the assumption that any target code selection value is as
5239 likely as any other.
5241 The transformation is performed by splitting the ordered
5242 list into two equal sections plus a pivot. The parts are
5243 then attached to the pivot as left and right branches. Each
5244 branch is is then transformed recursively. */
5247 balance_case_nodes (head, parent)
5248 case_node_ptr *head;
5249 case_node_ptr parent;
5251 register case_node_ptr np;
5259 register case_node_ptr *npp;
5262 /* Count the number of entries on branch. Also count the ranges. */
5266 if (!tree_int_cst_equal (np->low, np->high))
5270 cost += cost_table[TREE_INT_CST_LOW (np->high)];
5274 cost += cost_table[TREE_INT_CST_LOW (np->low)];
5282 /* Split this list if it is long enough for that to help. */
5287 /* Find the place in the list that bisects the list's total cost,
5288 Here I gets half the total cost. */
5293 /* Skip nodes while their cost does not reach that amount. */
5294 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5295 i -= cost_table[TREE_INT_CST_LOW ((*npp)->high)];
5296 i -= cost_table[TREE_INT_CST_LOW ((*npp)->low)];
5299 npp = &(*npp)->right;
5304 /* Leave this branch lopsided, but optimize left-hand
5305 side and fill in `parent' fields for right-hand side. */
5307 np->parent = parent;
5308 balance_case_nodes (&np->left, np);
5309 for (; np->right; np = np->right)
5310 np->right->parent = np;
5314 /* If there are just three nodes, split at the middle one. */
5316 npp = &(*npp)->right;
5319 /* Find the place in the list that bisects the list's total cost,
5320 where ranges count as 2.
5321 Here I gets half the total cost. */
5322 i = (i + ranges + 1) / 2;
5325 /* Skip nodes while their cost does not reach that amount. */
5326 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5331 npp = &(*npp)->right;
5336 np->parent = parent;
5339 /* Optimize each of the two split parts. */
5340 balance_case_nodes (&np->left, np);
5341 balance_case_nodes (&np->right, np);
5345 /* Else leave this branch as one level,
5346 but fill in `parent' fields. */
5348 np->parent = parent;
5349 for (; np->right; np = np->right)
5350 np->right->parent = np;
5355 /* Search the parent sections of the case node tree
5356 to see if a test for the lower bound of NODE would be redundant.
5357 INDEX_TYPE is the type of the index expression.
5359 The instructions to generate the case decision tree are
5360 output in the same order as nodes are processed so it is
5361 known that if a parent node checks the range of the current
5362 node minus one that the current node is bounded at its lower
5363 span. Thus the test would be redundant. */
5366 node_has_low_bound (node, index_type)
5371 case_node_ptr pnode;
5373 /* If the lower bound of this node is the lowest value in the index type,
5374 we need not test it. */
5376 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5379 /* If this node has a left branch, the value at the left must be less
5380 than that at this node, so it cannot be bounded at the bottom and
5381 we need not bother testing any further. */
5386 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5387 node->low, integer_one_node));
5389 /* If the subtraction above overflowed, we can't verify anything.
5390 Otherwise, look for a parent that tests our value - 1. */
5392 if (! tree_int_cst_lt (low_minus_one, node->low))
5395 for (pnode = node->parent; pnode; pnode = pnode->parent)
5396 if (tree_int_cst_equal (low_minus_one, pnode->high))
5402 /* Search the parent sections of the case node tree
5403 to see if a test for the upper bound of NODE would be redundant.
5404 INDEX_TYPE is the type of the index expression.
5406 The instructions to generate the case decision tree are
5407 output in the same order as nodes are processed so it is
5408 known that if a parent node checks the range of the current
5409 node plus one that the current node is bounded at its upper
5410 span. Thus the test would be redundant. */
5413 node_has_high_bound (node, index_type)
5418 case_node_ptr pnode;
5420 /* If the upper bound of this node is the highest value in the type
5421 of the index expression, we need not test against it. */
5423 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
5426 /* If this node has a right branch, the value at the right must be greater
5427 than that at this node, so it cannot be bounded at the top and
5428 we need not bother testing any further. */
5433 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
5434 node->high, integer_one_node));
5436 /* If the addition above overflowed, we can't verify anything.
5437 Otherwise, look for a parent that tests our value + 1. */
5439 if (! tree_int_cst_lt (node->high, high_plus_one))
5442 for (pnode = node->parent; pnode; pnode = pnode->parent)
5443 if (tree_int_cst_equal (high_plus_one, pnode->low))
5449 /* Search the parent sections of the
5450 case node tree to see if both tests for the upper and lower
5451 bounds of NODE would be redundant. */
5454 node_is_bounded (node, index_type)
5458 return (node_has_low_bound (node, index_type)
5459 && node_has_high_bound (node, index_type));
5462 /* Emit an unconditional jump to LABEL unless it would be dead code. */
5465 emit_jump_if_reachable (label)
5468 if (GET_CODE (get_last_insn ()) != BARRIER)
5472 /* Emit step-by-step code to select a case for the value of INDEX.
5473 The thus generated decision tree follows the form of the
5474 case-node binary tree NODE, whose nodes represent test conditions.
5475 INDEX_TYPE is the type of the index of the switch.
5477 Care is taken to prune redundant tests from the decision tree
5478 by detecting any boundary conditions already checked by
5479 emitted rtx. (See node_has_high_bound, node_has_low_bound
5480 and node_is_bounded, above.)
5482 Where the test conditions can be shown to be redundant we emit
5483 an unconditional jump to the target code. As a further
5484 optimization, the subordinates of a tree node are examined to
5485 check for bounded nodes. In this case conditional and/or
5486 unconditional jumps as a result of the boundary check for the
5487 current node are arranged to target the subordinates associated
5488 code for out of bound conditions on the current node node.
5490 We can assume that when control reaches the code generated here,
5491 the index value has already been compared with the parents
5492 of this node, and determined to be on the same side of each parent
5493 as this node is. Thus, if this node tests for the value 51,
5494 and a parent tested for 52, we don't need to consider
5495 the possibility of a value greater than 51. If another parent
5496 tests for the value 50, then this node need not test anything. */
5499 emit_case_nodes (index, node, default_label, index_type)
5505 /* If INDEX has an unsigned type, we must make unsigned branches. */
5506 int unsignedp = TREE_UNSIGNED (index_type);
5507 typedef rtx rtx_function ();
5508 rtx_function *gen_bgt_pat = unsignedp ? gen_bgtu : gen_bgt;
5509 rtx_function *gen_bge_pat = unsignedp ? gen_bgeu : gen_bge;
5510 rtx_function *gen_blt_pat = unsignedp ? gen_bltu : gen_blt;
5511 rtx_function *gen_ble_pat = unsignedp ? gen_bleu : gen_ble;
5512 enum machine_mode mode = GET_MODE (index);
5514 /* See if our parents have already tested everything for us.
5515 If they have, emit an unconditional jump for this node. */
5516 if (node_is_bounded (node, index_type))
5517 emit_jump (label_rtx (node->code_label));
5519 else if (tree_int_cst_equal (node->low, node->high))
5521 /* Node is single valued. First see if the index expression matches
5522 this node and then check our children, if any. */
5524 do_jump_if_equal (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5525 label_rtx (node->code_label), unsignedp);
5527 if (node->right != 0 && node->left != 0)
5529 /* This node has children on both sides.
5530 Dispatch to one side or the other
5531 by comparing the index value with this node's value.
5532 If one subtree is bounded, check that one first,
5533 so we can avoid real branches in the tree. */
5535 if (node_is_bounded (node->right, index_type))
5537 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5539 GT, NULL_RTX, mode, unsignedp, 0);
5541 emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
5542 emit_case_nodes (index, node->left, default_label, index_type);
5545 else if (node_is_bounded (node->left, index_type))
5547 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5549 LT, NULL_RTX, mode, unsignedp, 0);
5550 emit_jump_insn ((*gen_blt_pat) (label_rtx (node->left->code_label)));
5551 emit_case_nodes (index, node->right, default_label, index_type);
5556 /* Neither node is bounded. First distinguish the two sides;
5557 then emit the code for one side at a time. */
5560 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5562 /* See if the value is on the right. */
5563 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5565 GT, NULL_RTX, mode, unsignedp, 0);
5566 emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
5568 /* Value must be on the left.
5569 Handle the left-hand subtree. */
5570 emit_case_nodes (index, node->left, default_label, index_type);
5571 /* If left-hand subtree does nothing,
5573 emit_jump_if_reachable (default_label);
5575 /* Code branches here for the right-hand subtree. */
5576 expand_label (test_label);
5577 emit_case_nodes (index, node->right, default_label, index_type);
5581 else if (node->right != 0 && node->left == 0)
5583 /* Here we have a right child but no left so we issue conditional
5584 branch to default and process the right child.
5586 Omit the conditional branch to default if we it avoid only one
5587 right child; it costs too much space to save so little time. */
5589 if (node->right->right || node->right->left
5590 || !tree_int_cst_equal (node->right->low, node->right->high))
5592 if (!node_has_low_bound (node, index_type))
5594 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5596 LT, NULL_RTX, mode, unsignedp, 0);
5597 emit_jump_insn ((*gen_blt_pat) (default_label));
5600 emit_case_nodes (index, node->right, default_label, index_type);
5603 /* We cannot process node->right normally
5604 since we haven't ruled out the numbers less than
5605 this node's value. So handle node->right explicitly. */
5606 do_jump_if_equal (index,
5607 expand_expr (node->right->low, NULL_RTX,
5609 label_rtx (node->right->code_label), unsignedp);
5612 else if (node->right == 0 && node->left != 0)
5614 /* Just one subtree, on the left. */
5616 #if 0 /* The following code and comment were formerly part
5617 of the condition here, but they didn't work
5618 and I don't understand what the idea was. -- rms. */
5619 /* If our "most probable entry" is less probable
5620 than the default label, emit a jump to
5621 the default label using condition codes
5622 already lying around. With no right branch,
5623 a branch-greater-than will get us to the default
5626 && cost_table[TREE_INT_CST_LOW (node->high)] < 12)
5629 if (node->left->left || node->left->right
5630 || !tree_int_cst_equal (node->left->low, node->left->high))
5632 if (!node_has_high_bound (node, index_type))
5634 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5636 GT, NULL_RTX, mode, unsignedp, 0);
5637 emit_jump_insn ((*gen_bgt_pat) (default_label));
5640 emit_case_nodes (index, node->left, default_label, index_type);
5643 /* We cannot process node->left normally
5644 since we haven't ruled out the numbers less than
5645 this node's value. So handle node->left explicitly. */
5646 do_jump_if_equal (index,
5647 expand_expr (node->left->low, NULL_RTX,
5649 label_rtx (node->left->code_label), unsignedp);
5654 /* Node is a range. These cases are very similar to those for a single
5655 value, except that we do not start by testing whether this node
5656 is the one to branch to. */
5658 if (node->right != 0 && node->left != 0)
5660 /* Node has subtrees on both sides.
5661 If the right-hand subtree is bounded,
5662 test for it first, since we can go straight there.
5663 Otherwise, we need to make a branch in the control structure,
5664 then handle the two subtrees. */
5665 tree test_label = 0;
5667 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5669 GT, NULL_RTX, mode, unsignedp, 0);
5671 if (node_is_bounded (node->right, index_type))
5672 /* Right hand node is fully bounded so we can eliminate any
5673 testing and branch directly to the target code. */
5674 emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
5677 /* Right hand node requires testing.
5678 Branch to a label where we will handle it later. */
5680 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5681 emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
5684 /* Value belongs to this node or to the left-hand subtree. */
5686 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5687 GE, NULL_RTX, mode, unsignedp, 0);
5688 emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
5690 /* Handle the left-hand subtree. */
5691 emit_case_nodes (index, node->left, default_label, index_type);
5693 /* If right node had to be handled later, do that now. */
5697 /* If the left-hand subtree fell through,
5698 don't let it fall into the right-hand subtree. */
5699 emit_jump_if_reachable (default_label);
5701 expand_label (test_label);
5702 emit_case_nodes (index, node->right, default_label, index_type);
5706 else if (node->right != 0 && node->left == 0)
5708 /* Deal with values to the left of this node,
5709 if they are possible. */
5710 if (!node_has_low_bound (node, index_type))
5712 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
5714 LT, NULL_RTX, mode, unsignedp, 0);
5715 emit_jump_insn ((*gen_blt_pat) (default_label));
5718 /* Value belongs to this node or to the right-hand subtree. */
5720 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5722 LE, NULL_RTX, mode, unsignedp, 0);
5723 emit_jump_insn ((*gen_ble_pat) (label_rtx (node->code_label)));
5725 emit_case_nodes (index, node->right, default_label, index_type);
5728 else if (node->right == 0 && node->left != 0)
5730 /* Deal with values to the right of this node,
5731 if they are possible. */
5732 if (!node_has_high_bound (node, index_type))
5734 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5736 GT, NULL_RTX, mode, unsignedp, 0);
5737 emit_jump_insn ((*gen_bgt_pat) (default_label));
5740 /* Value belongs to this node or to the left-hand subtree. */
5742 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
5743 GE, NULL_RTX, mode, unsignedp, 0);
5744 emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
5746 emit_case_nodes (index, node->left, default_label, index_type);
5751 /* Node has no children so we check low and high bounds to remove
5752 redundant tests. Only one of the bounds can exist,
5753 since otherwise this node is bounded--a case tested already. */
5755 if (!node_has_high_bound (node, index_type))
5757 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
5759 GT, NULL_RTX, mode, unsignedp, 0);
5760 emit_jump_insn ((*gen_bgt_pat) (default_label));
5763 if (!node_has_low_bound (node, index_type))
5765 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
5767 LT, NULL_RTX, mode, unsignedp, 0);
5768 emit_jump_insn ((*gen_blt_pat) (default_label));
5771 emit_jump (label_rtx (node->code_label));
5776 /* These routines are used by the loop unrolling code. They copy BLOCK trees
5777 so that the debugging info will be correct for the unrolled loop. */
5779 /* Indexed by block number, contains a pointer to the N'th block node. */
5781 static tree *block_vector;
5784 find_loop_tree_blocks ()
5786 tree block = DECL_INITIAL (current_function_decl);
5788 /* There first block is for the function body, and does not have
5789 corresponding block notes. Don't include it in the block vector. */
5790 block = BLOCK_SUBBLOCKS (block);
5792 block_vector = identify_blocks (block, get_insns ());
5796 unroll_block_trees ()
5798 tree block = DECL_INITIAL (current_function_decl);
5800 reorder_blocks (block_vector, block, get_insns ());