1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 1988, 1989, 1992 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"
53 #define obstack_chunk_alloc xmalloc
54 #define obstack_chunk_free free
55 struct obstack stmt_obstack;
57 /* Filename and line number of last line-number note,
58 whether we actually emitted it or not. */
62 /* Nonzero if within a ({...}) grouping, in which case we must
63 always compute a value for each expr-stmt in case it is the last one. */
65 int expr_stmts_for_value;
67 /* Each time we expand an expression-statement,
68 record the expr's type and its RTL value here. */
70 static tree last_expr_type;
71 static rtx last_expr_value;
73 /* Each time we expand the end of a binding contour (in `expand_end_bindings')
74 and we emit a new NOTE_INSN_BLOCK_END note, we save a pointer to it here.
75 This is used by the `remember_end_note' function to record the endpoint
76 of each generated block in its associated BLOCK node. */
78 static rtx last_block_end_note;
80 /* Number of binding contours started so far in this function. */
82 int block_start_count;
84 /* Nonzero if function being compiled needs to
85 return the address of where it has put a structure value. */
87 extern int current_function_returns_pcc_struct;
89 /* Label that will go on parm cleanup code, if any.
90 Jumping to this label runs cleanup code for parameters, if
91 such code must be run. Following this code is the logical return label. */
93 extern rtx cleanup_label;
95 /* Label that will go on function epilogue.
96 Jumping to this label serves as a "return" instruction
97 on machines which require execution of the epilogue on all returns. */
99 extern rtx return_label;
101 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
102 So we can mark them all live at the end of the function, if nonopt. */
103 extern rtx save_expr_regs;
105 /* Offset to end of allocated area of stack frame.
106 If stack grows down, this is the address of the last stack slot allocated.
107 If stack grows up, this is the address for the next slot. */
108 extern int frame_offset;
110 /* Label to jump back to for tail recursion, or 0 if we have
111 not yet needed one for this function. */
112 extern rtx tail_recursion_label;
114 /* Place after which to insert the tail_recursion_label if we need one. */
115 extern rtx tail_recursion_reentry;
117 /* Location at which to save the argument pointer if it will need to be
118 referenced. There are two cases where this is done: if nonlocal gotos
119 exist, or if vars whose is an offset from the argument pointer will be
120 needed by inner routines. */
122 extern rtx arg_pointer_save_area;
124 /* Chain of all RTL_EXPRs that have insns in them. */
125 extern tree rtl_expr_chain;
127 #if 0 /* Turned off because 0 seems to work just as well. */
128 /* Cleanup lists are required for binding levels regardless of whether
129 that binding level has cleanups or not. This node serves as the
130 cleanup list whenever an empty list is required. */
131 static tree empty_cleanup_list;
134 /* Functions and data structures for expanding case statements. */
136 /* Case label structure, used to hold info on labels within case
137 statements. We handle "range" labels; for a single-value label
138 as in C, the high and low limits are the same.
140 A chain of case nodes is initially maintained via the RIGHT fields
141 in the nodes. Nodes with higher case values are later in the list.
143 Switch statements can be output in one of two forms. A branch table
144 is used if there are more than a few labels and the labels are dense
145 within the range between the smallest and largest case value. If a
146 branch table is used, no further manipulations are done with the case
149 The alternative to the use of a branch table is to generate a series
150 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
151 and PARENT fields to hold a binary tree. Initially the tree is
152 totally unbalanced, with everything on the right. We balance the tree
153 with nodes on the left having lower case values than the parent
154 and nodes on the right having higher values. We then output the tree
159 struct case_node *left; /* Left son in binary tree */
160 struct case_node *right; /* Right son in binary tree; also node chain */
161 struct case_node *parent; /* Parent of node in binary tree */
162 tree low; /* Lowest index value for this label */
163 tree high; /* Highest index value for this label */
164 tree code_label; /* Label to jump to when node matches */
167 typedef struct case_node case_node;
168 typedef struct case_node *case_node_ptr;
170 /* These are used by estimate_case_costs and balance_case_nodes. */
172 /* This must be a signed type, and non-ANSI compilers lack signed char. */
173 static short *cost_table;
174 static int use_cost_table;
176 static int estimate_case_costs ();
177 static void balance_case_nodes ();
178 static void emit_case_nodes ();
179 static void group_case_nodes ();
180 static void emit_jump_if_reachable ();
182 static int warn_if_unused_value ();
183 static void expand_goto_internal ();
184 static int expand_fixup ();
186 void free_temp_slots ();
187 static void expand_cleanups ();
188 static void expand_null_return_1 ();
189 static int tail_recursion_args ();
190 static void do_jump_if_equal ();
192 /* Stack of control and binding constructs we are currently inside.
194 These constructs begin when you call `expand_start_WHATEVER'
195 and end when you call `expand_end_WHATEVER'. This stack records
196 info about how the construct began that tells the end-function
197 what to do. It also may provide information about the construct
198 to alter the behavior of other constructs within the body.
199 For example, they may affect the behavior of C `break' and `continue'.
201 Each construct gets one `struct nesting' object.
202 All of these objects are chained through the `all' field.
203 `nesting_stack' points to the first object (innermost construct).
204 The position of an entry on `nesting_stack' is in its `depth' field.
206 Each type of construct has its own individual stack.
207 For example, loops have `loop_stack'. Each object points to the
208 next object of the same type through the `next' field.
210 Some constructs are visible to `break' exit-statements and others
211 are not. Which constructs are visible depends on the language.
212 Therefore, the data structure allows each construct to be visible
213 or not, according to the args given when the construct is started.
214 The construct is visible if the `exit_label' field is non-null.
215 In that case, the value should be a CODE_LABEL rtx. */
220 struct nesting *next;
225 /* For conds (if-then and if-then-else statements). */
228 /* Label for the end of the if construct.
229 There is none if EXITFLAG was not set
230 and no `else' has been seen yet. */
232 /* Label for the end of this alternative.
233 This may be the end of the if or the next else/elseif. */
239 /* Label at the top of the loop; place to loop back to. */
241 /* Label at the end of the whole construct. */
243 /* Label for `continue' statement to jump to;
244 this is in front of the stepper of the loop. */
247 /* For variable binding contours. */
250 /* Sequence number of this binding contour within the function,
251 in order of entry. */
252 int block_start_count;
253 /* Nonzero => value to restore stack to on exit. */
255 /* The NOTE that starts this contour.
256 Used by expand_goto to check whether the destination
257 is within each contour or not. */
259 /* Innermost containing binding contour that has a stack level. */
260 struct nesting *innermost_stack_block;
261 /* List of cleanups to be run on exit from this contour.
262 This is a list of expressions to be evaluated.
263 The TREE_PURPOSE of each link is the ..._DECL node
264 which the cleanup pertains to. */
266 /* List of cleanup-lists of blocks containing this block,
267 as they were at the locus where this block appears.
268 There is an element for each containing block,
269 ordered innermost containing block first.
270 The tail of this list can be 0 (was empty_cleanup_list),
271 if all remaining elements would be empty lists.
272 The element's TREE_VALUE is the cleanup-list of that block,
273 which may be null. */
275 /* Chain of labels defined inside this binding contour.
276 For contours that have stack levels or cleanups. */
277 struct label_chain *label_chain;
278 /* Number of function calls seen, as of start of this block. */
279 int function_call_count;
281 /* For switch (C) or case (Pascal) statements,
282 and also for dummies (see `expand_start_case_dummy'). */
285 /* The insn after which the case dispatch should finally
286 be emitted. Zero for a dummy. */
288 /* A list of case labels, kept in ascending order by value
289 as the list is built.
290 During expand_end_case, this list may be rearranged into a
291 nearly balanced binary tree. */
292 struct case_node *case_list;
293 /* Label to jump to if no case matches. */
295 /* The expression to be dispatched on. */
297 /* Type that INDEX_EXPR should be converted to. */
299 /* Number of range exprs in case statement. */
301 /* Name of this kind of statement, for warnings. */
303 /* Nonzero if a case label has been seen in this case stmt. */
306 /* For exception contours. */
309 /* List of exceptions raised. This is a TREE_LIST
310 of whatever you want. */
312 /* List of exceptions caught. This is also a TREE_LIST
313 of whatever you want. As a special case, it has the
314 value `void_type_node' if it handles default exceptions. */
317 /* First insn of TRY block, in case resumptive model is needed. */
319 /* Label for the catch clauses. */
321 /* Label for unhandled exceptions. */
323 /* Label at the end of whole construct. */
325 /* Label which "escapes" the exception construct.
326 Like EXIT_LABEL for BREAK construct, but for exceptions. */
332 /* Chain of all pending binding contours. */
333 struct nesting *block_stack;
335 /* If any new stacks are added here, add them to POPSTACKS too. */
337 /* Chain of all pending binding contours that restore stack levels
339 struct nesting *stack_block_stack;
341 /* Chain of all pending conditional statements. */
342 struct nesting *cond_stack;
344 /* Chain of all pending loops. */
345 struct nesting *loop_stack;
347 /* Chain of all pending case or switch statements. */
348 struct nesting *case_stack;
350 /* Chain of all pending exception contours. */
351 struct nesting *except_stack;
353 /* Separate chain including all of the above,
354 chained through the `all' field. */
355 struct nesting *nesting_stack;
357 /* Number of entries on nesting_stack now. */
360 /* Allocate and return a new `struct nesting'. */
362 #define ALLOC_NESTING() \
363 (struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
365 /* Pop the nesting stack element by element until we pop off
366 the element which is at the top of STACK.
367 Update all the other stacks, popping off elements from them
368 as we pop them from nesting_stack. */
370 #define POPSTACK(STACK) \
371 do { struct nesting *target = STACK; \
372 struct nesting *this; \
373 do { this = nesting_stack; \
374 if (loop_stack == this) \
375 loop_stack = loop_stack->next; \
376 if (cond_stack == this) \
377 cond_stack = cond_stack->next; \
378 if (block_stack == this) \
379 block_stack = block_stack->next; \
380 if (stack_block_stack == this) \
381 stack_block_stack = stack_block_stack->next; \
382 if (case_stack == this) \
383 case_stack = case_stack->next; \
384 if (except_stack == this) \
385 except_stack = except_stack->next; \
386 nesting_depth = nesting_stack->depth - 1; \
387 nesting_stack = this->all; \
388 obstack_free (&stmt_obstack, this); } \
389 while (this != target); } while (0)
391 /* In some cases it is impossible to generate code for a forward goto
392 until the label definition is seen. This happens when it may be necessary
393 for the goto to reset the stack pointer: we don't yet know how to do that.
394 So expand_goto puts an entry on this fixup list.
395 Each time a binding contour that resets the stack is exited,
397 If the target label has now been defined, we can insert the proper code. */
401 /* Points to following fixup. */
402 struct goto_fixup *next;
403 /* Points to the insn before the jump insn.
404 If more code must be inserted, it goes after this insn. */
406 /* The LABEL_DECL that this jump is jumping to, or 0
407 for break, continue or return. */
409 /* The BLOCK for the place where this goto was found. */
411 /* The CODE_LABEL rtx that this is jumping to. */
413 /* Number of binding contours started in current function
414 before the label reference. */
415 int block_start_count;
416 /* The outermost stack level that should be restored for this jump.
417 Each time a binding contour that resets the stack is exited,
418 if the target label is *not* yet defined, this slot is updated. */
420 /* List of lists of cleanup expressions to be run by this goto.
421 There is one element for each block that this goto is within.
422 The tail of this list can be 0 (was empty_cleanup_list),
423 if all remaining elements would be empty.
424 The TREE_VALUE contains the cleanup list of that block as of the
425 time this goto was seen.
426 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
427 tree cleanup_list_list;
430 static struct goto_fixup *goto_fixup_chain;
432 /* Within any binding contour that must restore a stack level,
433 all labels are recorded with a chain of these structures. */
437 /* Points to following fixup. */
438 struct label_chain *next;
445 gcc_obstack_init (&stmt_obstack);
447 empty_cleanup_list = build_tree_list (NULL_TREE, NULL_TREE);
452 init_stmt_for_function ()
454 /* We are not currently within any block, conditional, loop or case. */
462 block_start_count = 0;
464 /* No gotos have been expanded yet. */
465 goto_fixup_chain = 0;
467 /* We are not processing a ({...}) grouping. */
468 expr_stmts_for_value = 0;
476 p->block_stack = block_stack;
477 p->stack_block_stack = stack_block_stack;
478 p->cond_stack = cond_stack;
479 p->loop_stack = loop_stack;
480 p->case_stack = case_stack;
481 p->nesting_stack = nesting_stack;
482 p->nesting_depth = nesting_depth;
483 p->block_start_count = block_start_count;
484 p->last_expr_type = last_expr_type;
485 p->last_expr_value = last_expr_value;
486 p->expr_stmts_for_value = expr_stmts_for_value;
487 p->emit_filename = emit_filename;
488 p->emit_lineno = emit_lineno;
489 p->goto_fixup_chain = goto_fixup_chain;
493 restore_stmt_status (p)
496 block_stack = p->block_stack;
497 stack_block_stack = p->stack_block_stack;
498 cond_stack = p->cond_stack;
499 loop_stack = p->loop_stack;
500 case_stack = p->case_stack;
501 nesting_stack = p->nesting_stack;
502 nesting_depth = p->nesting_depth;
503 block_start_count = p->block_start_count;
504 last_expr_type = p->last_expr_type;
505 last_expr_value = p->last_expr_value;
506 expr_stmts_for_value = p->expr_stmts_for_value;
507 emit_filename = p->emit_filename;
508 emit_lineno = p->emit_lineno;
509 goto_fixup_chain = p->goto_fixup_chain;
512 /* Emit a no-op instruction. */
517 rtx last_insn = get_last_insn ();
519 && (GET_CODE (last_insn) == CODE_LABEL
520 || prev_real_insn (last_insn) == 0))
521 emit_insn (gen_nop ());
524 /* Return the rtx-label that corresponds to a LABEL_DECL,
525 creating it if necessary. */
531 if (TREE_CODE (label) != LABEL_DECL)
534 if (DECL_RTL (label))
535 return DECL_RTL (label);
537 return DECL_RTL (label) = gen_label_rtx ();
540 /* Add an unconditional jump to LABEL as the next sequential instruction. */
546 do_pending_stack_adjust ();
547 emit_jump_insn (gen_jump (label));
551 /* Emit code to jump to the address
552 specified by the pointer expression EXP. */
555 expand_computed_goto (exp)
558 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
560 emit_indirect_jump (x);
563 /* Handle goto statements and the labels that they can go to. */
565 /* Specify the location in the RTL code of a label LABEL,
566 which is a LABEL_DECL tree node.
568 This is used for the kind of label that the user can jump to with a
569 goto statement, and for alternatives of a switch or case statement.
570 RTL labels generated for loops and conditionals don't go through here;
571 they are generated directly at the RTL level, by other functions below.
573 Note that this has nothing to do with defining label *names*.
574 Languages vary in how they do that and what that even means. */
580 struct label_chain *p;
582 do_pending_stack_adjust ();
583 emit_label (label_rtx (label));
584 if (DECL_NAME (label))
585 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
587 if (stack_block_stack != 0)
589 p = (struct label_chain *) oballoc (sizeof (struct label_chain));
590 p->next = stack_block_stack->data.block.label_chain;
591 stack_block_stack->data.block.label_chain = p;
596 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
597 from nested functions. */
600 declare_nonlocal_label (label)
603 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
604 LABEL_PRESERVE_P (label_rtx (label)) = 1;
605 if (nonlocal_goto_handler_slot == 0)
607 nonlocal_goto_handler_slot
608 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
609 emit_stack_save (SAVE_NONLOCAL,
610 &nonlocal_goto_stack_level,
611 PREV_INSN (tail_recursion_reentry));
615 /* Generate RTL code for a `goto' statement with target label LABEL.
616 LABEL should be a LABEL_DECL tree node that was or will later be
617 defined with `expand_label'. */
623 /* Check for a nonlocal goto to a containing function. */
624 tree context = decl_function_context (label);
625 if (context != 0 && context != current_function_decl)
627 struct function *p = find_function_data (context);
628 rtx label_ref = gen_rtx (LABEL_REF, Pmode, label_rtx (label));
631 p->has_nonlocal_label = 1;
632 LABEL_REF_NONLOCAL_P (label_ref) = 1;
634 /* Copy the rtl for the slots so that they won't be shared in
635 case the virtual stack vars register gets instantiated differently
636 in the parent than in the child. */
638 #if HAVE_nonlocal_goto
639 if (HAVE_nonlocal_goto)
640 emit_insn (gen_nonlocal_goto (lookup_static_chain (label),
641 copy_rtx (p->nonlocal_goto_handler_slot),
642 copy_rtx (p->nonlocal_goto_stack_level),
649 /* Restore frame pointer for containing function.
650 This sets the actual hard register used for the frame pointer
651 to the location of the function's incoming static chain info.
652 The non-local goto handler will then adjust it to contain the
653 proper value and reload the argument pointer, if needed. */
654 emit_move_insn (frame_pointer_rtx, lookup_static_chain (label));
656 /* We have now loaded the frame pointer hardware register with
657 the address of that corresponds to the start of the virtual
658 stack vars. So replace virtual_stack_vars_rtx in all
659 addresses we use with stack_pointer_rtx. */
661 /* Get addr of containing function's current nonlocal goto handler,
662 which will do any cleanups and then jump to the label. */
663 addr = copy_rtx (p->nonlocal_goto_handler_slot);
664 temp = copy_to_reg (replace_rtx (addr, virtual_stack_vars_rtx,
667 /* Restore the stack pointer. Note this uses fp just restored. */
668 addr = p->nonlocal_goto_stack_level;
670 addr = replace_rtx (copy_rtx (addr),
671 virtual_stack_vars_rtx, frame_pointer_rtx);
673 emit_stack_restore (SAVE_NONLOCAL, addr, NULL_RTX);
675 /* Put in the static chain register the nonlocal label address. */
676 emit_move_insn (static_chain_rtx, label_ref);
677 /* USE of frame_pointer_rtx added for consistency; not clear if
679 emit_insn (gen_rtx (USE, VOIDmode, frame_pointer_rtx));
680 emit_insn (gen_rtx (USE, VOIDmode, stack_pointer_rtx));
681 emit_insn (gen_rtx (USE, VOIDmode, static_chain_rtx));
682 emit_indirect_jump (temp);
686 expand_goto_internal (label, label_rtx (label), NULL_RTX);
689 /* Generate RTL code for a `goto' statement with target label BODY.
690 LABEL should be a LABEL_REF.
691 LAST_INSN, if non-0, is the rtx we should consider as the last
692 insn emitted (for the purposes of cleaning up a return). */
695 expand_goto_internal (body, label, last_insn)
700 struct nesting *block;
703 if (GET_CODE (label) != CODE_LABEL)
706 /* If label has already been defined, we can tell now
707 whether and how we must alter the stack level. */
709 if (PREV_INSN (label) != 0)
711 /* Find the innermost pending block that contains the label.
712 (Check containment by comparing insn-uids.)
713 Then restore the outermost stack level within that block,
714 and do cleanups of all blocks contained in it. */
715 for (block = block_stack; block; block = block->next)
717 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
719 if (block->data.block.stack_level != 0)
720 stack_level = block->data.block.stack_level;
721 /* Execute the cleanups for blocks we are exiting. */
722 if (block->data.block.cleanups != 0)
724 expand_cleanups (block->data.block.cleanups, NULL_TREE);
725 do_pending_stack_adjust ();
731 /* Ensure stack adjust isn't done by emit_jump, as this would clobber
732 the stack pointer. This one should be deleted as dead by flow. */
733 clear_pending_stack_adjust ();
734 do_pending_stack_adjust ();
735 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
738 if (body != 0 && DECL_TOO_LATE (body))
739 error ("jump to `%s' invalidly jumps into binding contour",
740 IDENTIFIER_POINTER (DECL_NAME (body)));
742 /* Label not yet defined: may need to put this goto
743 on the fixup list. */
744 else if (! expand_fixup (body, label, last_insn))
746 /* No fixup needed. Record that the label is the target
747 of at least one goto that has no fixup. */
749 TREE_ADDRESSABLE (body) = 1;
755 /* Generate if necessary a fixup for a goto
756 whose target label in tree structure (if any) is TREE_LABEL
757 and whose target in rtl is RTL_LABEL.
759 If LAST_INSN is nonzero, we pretend that the jump appears
760 after insn LAST_INSN instead of at the current point in the insn stream.
762 The fixup will be used later to insert insns just before the goto.
763 Those insns will restore the stack level as appropriate for the
764 target label, and will (in the case of C++) also invoke any object
765 destructors which have to be invoked when we exit the scopes which
766 are exited by the goto.
768 Value is nonzero if a fixup is made. */
771 expand_fixup (tree_label, rtl_label, last_insn)
776 struct nesting *block, *end_block;
778 /* See if we can recognize which block the label will be output in.
779 This is possible in some very common cases.
780 If we succeed, set END_BLOCK to that block.
781 Otherwise, set it to 0. */
784 && (rtl_label == cond_stack->data.cond.endif_label
785 || rtl_label == cond_stack->data.cond.next_label))
786 end_block = cond_stack;
787 /* If we are in a loop, recognize certain labels which
788 are likely targets. This reduces the number of fixups
789 we need to create. */
791 && (rtl_label == loop_stack->data.loop.start_label
792 || rtl_label == loop_stack->data.loop.end_label
793 || rtl_label == loop_stack->data.loop.continue_label))
794 end_block = loop_stack;
798 /* Now set END_BLOCK to the binding level to which we will return. */
802 struct nesting *next_block = end_block->all;
805 /* First see if the END_BLOCK is inside the innermost binding level.
806 If so, then no cleanups or stack levels are relevant. */
807 while (next_block && next_block != block)
808 next_block = next_block->all;
813 /* Otherwise, set END_BLOCK to the innermost binding level
814 which is outside the relevant control-structure nesting. */
815 next_block = block_stack->next;
816 for (block = block_stack; block != end_block; block = block->all)
817 if (block == next_block)
818 next_block = next_block->next;
819 end_block = next_block;
822 /* Does any containing block have a stack level or cleanups?
823 If not, no fixup is needed, and that is the normal case
824 (the only case, for standard C). */
825 for (block = block_stack; block != end_block; block = block->next)
826 if (block->data.block.stack_level != 0
827 || block->data.block.cleanups != 0)
830 if (block != end_block)
832 /* Ok, a fixup is needed. Add a fixup to the list of such. */
833 struct goto_fixup *fixup
834 = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
835 /* In case an old stack level is restored, make sure that comes
836 after any pending stack adjust. */
837 /* ?? If the fixup isn't to come at the present position,
838 doing the stack adjust here isn't useful. Doing it with our
839 settings at that location isn't useful either. Let's hope
842 do_pending_stack_adjust ();
843 fixup->target = tree_label;
844 fixup->target_rtl = rtl_label;
846 /* Create a BLOCK node and a corresponding matched set of
847 NOTE_INSN_BEGIN_BLOCK and NOTE_INSN_END_BLOCK notes at
848 this point. The notes will encapsulate any and all fixup
849 code which we might later insert at this point in the insn
850 stream. Also, the BLOCK node will be the parent (i.e. the
851 `SUPERBLOCK') of any other BLOCK nodes which we might create
852 later on when we are expanding the fixup code. */
855 register rtx original_before_jump
856 = last_insn ? last_insn : get_last_insn ();
860 fixup->before_jump = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
861 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
862 fixup->context = poplevel (1, 0, 0); /* Create the BLOCK node now! */
864 emit_insns_after (fixup->before_jump, original_before_jump);
867 fixup->block_start_count = block_start_count;
868 fixup->stack_level = 0;
869 fixup->cleanup_list_list
870 = (((block->data.block.outer_cleanups
872 && block->data.block.outer_cleanups != empty_cleanup_list
875 || block->data.block.cleanups)
876 ? tree_cons (NULL_TREE, block->data.block.cleanups,
877 block->data.block.outer_cleanups)
879 fixup->next = goto_fixup_chain;
880 goto_fixup_chain = fixup;
886 /* When exiting a binding contour, process all pending gotos requiring fixups.
887 THISBLOCK is the structure that describes the block being exited.
888 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
889 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
890 FIRST_INSN is the insn that began this contour.
892 Gotos that jump out of this contour must restore the
893 stack level and do the cleanups before actually jumping.
895 DONT_JUMP_IN nonzero means report error there is a jump into this
896 contour from before the beginning of the contour.
897 This is also done if STACK_LEVEL is nonzero. */
900 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
901 struct nesting *thisblock;
907 register struct goto_fixup *f, *prev;
909 /* F is the fixup we are considering; PREV is the previous one. */
910 /* We run this loop in two passes so that cleanups of exited blocks
911 are run first, and blocks that are exited are marked so
914 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
916 /* Test for a fixup that is inactive because it is already handled. */
917 if (f->before_jump == 0)
919 /* Delete inactive fixup from the chain, if that is easy to do. */
921 prev->next = f->next;
923 /* Has this fixup's target label been defined?
924 If so, we can finalize it. */
925 else if (PREV_INSN (f->target_rtl) != 0)
927 register rtx cleanup_insns;
929 /* Get the first non-label after the label
930 this goto jumps to. If that's before this scope begins,
931 we don't have a jump into the scope. */
932 rtx after_label = f->target_rtl;
933 while (after_label != 0 && GET_CODE (after_label) == CODE_LABEL)
934 after_label = NEXT_INSN (after_label);
936 /* If this fixup jumped into this contour from before the beginning
937 of this contour, report an error. */
938 /* ??? Bug: this does not detect jumping in through intermediate
939 blocks that have stack levels or cleanups.
940 It detects only a problem with the innermost block
943 && (dont_jump_in || stack_level || cleanup_list)
944 /* If AFTER_LABEL is 0, it means the jump goes to the end
945 of the rtl, which means it jumps into this scope. */
947 || INSN_UID (first_insn) < INSN_UID (after_label))
948 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
949 && ! DECL_REGISTER (f->target))
951 error_with_decl (f->target,
952 "label `%s' used before containing binding contour");
953 /* Prevent multiple errors for one label. */
954 DECL_REGISTER (f->target) = 1;
957 /* We will expand the cleanups into a sequence of their own and
958 then later on we will attach this new sequence to the insn
959 stream just ahead of the actual jump insn. */
963 /* Temporarily restore the lexical context where we will
964 logically be inserting the fixup code. We do this for the
965 sake of getting the debugging information right. */
968 set_block (f->context);
970 /* Expand the cleanups for blocks this jump exits. */
971 if (f->cleanup_list_list)
974 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
975 /* Marked elements correspond to blocks that have been closed.
976 Do their cleanups. */
977 if (TREE_ADDRESSABLE (lists)
978 && TREE_VALUE (lists) != 0)
980 expand_cleanups (TREE_VALUE (lists), 0);
981 /* Pop any pushes done in the cleanups,
982 in case function is about to return. */
983 do_pending_stack_adjust ();
987 /* Restore stack level for the biggest contour that this
988 jump jumps out of. */
990 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
992 /* Finish up the sequence containing the insns which implement the
993 necessary cleanups, and then attach that whole sequence to the
994 insn stream just ahead of the actual jump insn. Attaching it
995 at that point insures that any cleanups which are in fact
996 implicit C++ object destructions (which must be executed upon
997 leaving the block) appear (to the debugger) to be taking place
998 in an area of the generated code where the object(s) being
999 destructed are still "in scope". */
1001 cleanup_insns = get_insns ();
1005 emit_insns_after (cleanup_insns, f->before_jump);
1012 /* Mark the cleanups of exited blocks so that they are executed
1013 by the code above. */
1014 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1015 if (f->before_jump != 0
1016 && PREV_INSN (f->target_rtl) == 0
1017 /* Label has still not appeared. If we are exiting a block with
1018 a stack level to restore, that started before the fixup,
1019 mark this stack level as needing restoration
1020 when the fixup is later finalized.
1021 Also mark the cleanup_list_list element for F
1022 that corresponds to this block, so that ultimately
1023 this block's cleanups will be executed by the code above. */
1025 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared,
1026 it means the label is undefined. That's erroneous, but possible. */
1027 && (thisblock->data.block.block_start_count
1028 <= f->block_start_count))
1030 tree lists = f->cleanup_list_list;
1031 for (; lists; lists = TREE_CHAIN (lists))
1032 /* If the following elt. corresponds to our containing block
1033 then the elt. must be for this block. */
1034 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1035 TREE_ADDRESSABLE (lists) = 1;
1038 f->stack_level = stack_level;
1042 /* Generate RTL for an asm statement (explicit assembler code).
1043 BODY is a STRING_CST node containing the assembler code text,
1044 or an ADDR_EXPR containing a STRING_CST. */
1050 if (TREE_CODE (body) == ADDR_EXPR)
1051 body = TREE_OPERAND (body, 0);
1053 emit_insn (gen_rtx (ASM_INPUT, VOIDmode,
1054 TREE_STRING_POINTER (body)));
1058 /* Generate RTL for an asm statement with arguments.
1059 STRING is the instruction template.
1060 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1061 Each output or input has an expression in the TREE_VALUE and
1062 a constraint-string in the TREE_PURPOSE.
1063 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1064 that is clobbered by this insn.
1066 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1067 Some elements of OUTPUTS may be replaced with trees representing temporary
1068 values. The caller should copy those temporary values to the originally
1071 VOL nonzero means the insn is volatile; don't optimize it. */
1074 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1075 tree string, outputs, inputs, clobbers;
1080 rtvec argvec, constraints;
1082 int ninputs = list_length (inputs);
1083 int noutputs = list_length (outputs);
1087 /* Vector of RTX's of evaluated output operands. */
1088 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1089 /* The insn we have emitted. */
1092 /* Count the number of meaningful clobbered registers, ignoring what
1093 we would ignore later. */
1095 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1097 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1098 i = decode_reg_name (regname);
1099 if (i >= 0 || i == -4)
1105 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1107 tree val = TREE_VALUE (tail);
1112 /* If there's an erroneous arg, emit no insn. */
1113 if (TREE_TYPE (val) == error_mark_node)
1116 /* Make sure constraint has `=' and does not have `+'. */
1119 for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1121 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1123 error ("output operand constraint contains `+'");
1126 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '=')
1131 error ("output operand constraint lacks `='");
1135 /* If an output operand is not a variable or indirect ref,
1137 create a SAVE_EXPR which is a pseudo-reg
1138 to act as an intermediate temporary.
1139 Make the asm insn write into that, then copy it to
1140 the real output operand. */
1142 while (TREE_CODE (val) == COMPONENT_REF
1143 || TREE_CODE (val) == ARRAY_REF)
1144 val = TREE_OPERAND (val, 0);
1146 if (TREE_CODE (val) != VAR_DECL
1147 && TREE_CODE (val) != PARM_DECL
1148 && TREE_CODE (val) != INDIRECT_REF)
1150 TREE_VALUE (tail) = save_expr (TREE_VALUE (tail));
1151 /* If it's a constant, print error now so don't crash later. */
1152 if (TREE_CODE (TREE_VALUE (tail)) != SAVE_EXPR)
1154 error ("invalid output in `asm'");
1159 output_rtx[i] = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1162 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1164 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1168 /* Make vectors for the expression-rtx and constraint strings. */
1170 argvec = rtvec_alloc (ninputs);
1171 constraints = rtvec_alloc (ninputs);
1173 body = gen_rtx (ASM_OPERANDS, VOIDmode,
1174 TREE_STRING_POINTER (string), "", 0, argvec, constraints,
1176 MEM_VOLATILE_P (body) = vol;
1178 /* Eval the inputs and put them into ARGVEC.
1179 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1182 for (tail = inputs; tail; tail = TREE_CHAIN (tail))
1186 /* If there's an erroneous arg, emit no insn,
1187 because the ASM_INPUT would get VOIDmode
1188 and that could cause a crash in reload. */
1189 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1191 if (TREE_PURPOSE (tail) == NULL_TREE)
1193 error ("hard register `%s' listed as input operand to `asm'",
1194 TREE_STRING_POINTER (TREE_VALUE (tail)) );
1198 /* Make sure constraint has neither `=' nor `+'. */
1200 for (j = 0; j < TREE_STRING_LENGTH (TREE_PURPOSE (tail)); j++)
1201 if (TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '='
1202 || TREE_STRING_POINTER (TREE_PURPOSE (tail))[j] == '+')
1204 error ("input operand constraint contains `%c'",
1205 TREE_STRING_POINTER (TREE_PURPOSE (tail))[j]);
1209 XVECEXP (body, 3, i) /* argvec */
1210 = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1211 XVECEXP (body, 4, i) /* constraints */
1212 = gen_rtx (ASM_INPUT, TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1213 TREE_STRING_POINTER (TREE_PURPOSE (tail)));
1217 /* Protect all the operands from the queue,
1218 now that they have all been evaluated. */
1220 for (i = 0; i < ninputs; i++)
1221 XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
1223 for (i = 0; i < noutputs; i++)
1224 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1226 /* Now, for each output, construct an rtx
1227 (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
1228 ARGVEC CONSTRAINTS))
1229 If there is more than one, put them inside a PARALLEL. */
1231 if (noutputs == 1 && nclobbers == 0)
1233 XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
1234 insn = emit_insn (gen_rtx (SET, VOIDmode, output_rtx[0], body));
1236 else if (noutputs == 0 && nclobbers == 0)
1238 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1239 insn = emit_insn (body);
1245 if (num == 0) num = 1;
1246 body = gen_rtx (PARALLEL, VOIDmode, rtvec_alloc (num + nclobbers));
1248 /* For each output operand, store a SET. */
1250 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1252 XVECEXP (body, 0, i)
1253 = gen_rtx (SET, VOIDmode,
1255 gen_rtx (ASM_OPERANDS, VOIDmode,
1256 TREE_STRING_POINTER (string),
1257 TREE_STRING_POINTER (TREE_PURPOSE (tail)),
1258 i, argvec, constraints,
1260 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1263 /* If there are no outputs (but there are some clobbers)
1264 store the bare ASM_OPERANDS into the PARALLEL. */
1267 XVECEXP (body, 0, i++) = obody;
1269 /* Store (clobber REG) for each clobbered register specified. */
1271 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1273 char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1274 int j = decode_reg_name (regname);
1278 if (j == -3) /* `cc', which is not a register */
1281 if (j == -4) /* `memory', don't cache memory across asm */
1283 XVECEXP (body, 0, i++)
1284 = gen_rtx (CLOBBER, VOIDmode,
1285 gen_rtx (MEM, QImode,
1286 gen_rtx (SCRATCH, VOIDmode, 0)));
1290 error ("unknown register name `%s' in `asm'", regname);
1294 /* Use QImode since that's guaranteed to clobber just one reg. */
1295 XVECEXP (body, 0, i++)
1296 = gen_rtx (CLOBBER, VOIDmode, gen_rtx (REG, QImode, j));
1299 insn = emit_insn (body);
1305 /* Generate RTL to evaluate the expression EXP
1306 and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
1309 expand_expr_stmt (exp)
1312 /* If -W, warn about statements with no side effects,
1313 except for an explicit cast to void (e.g. for assert()), and
1314 except inside a ({...}) where they may be useful. */
1315 if (expr_stmts_for_value == 0 && exp != error_mark_node)
1317 if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
1318 && !(TREE_CODE (exp) == CONVERT_EXPR
1319 && TREE_TYPE (exp) == void_type_node))
1320 warning_with_file_and_line (emit_filename, emit_lineno,
1321 "statement with no effect");
1322 else if (warn_unused)
1323 warn_if_unused_value (exp);
1325 last_expr_type = TREE_TYPE (exp);
1326 if (! flag_syntax_only)
1327 last_expr_value = expand_expr (exp,
1328 (expr_stmts_for_value
1329 ? NULL_RTX : const0_rtx),
1332 /* If all we do is reference a volatile value in memory,
1333 copy it to a register to be sure it is actually touched. */
1334 if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
1335 && TREE_THIS_VOLATILE (exp))
1337 if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
1339 else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
1340 copy_to_reg (last_expr_value);
1343 rtx lab = gen_label_rtx ();
1345 /* Compare the value with itself to reference it. */
1346 emit_cmp_insn (last_expr_value, last_expr_value, EQ,
1347 expand_expr (TYPE_SIZE (last_expr_type),
1348 NULL_RTX, VOIDmode, 0),
1350 TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT);
1351 emit_jump_insn ((*bcc_gen_fctn[(int) EQ]) (lab));
1356 /* If this expression is part of a ({...}) and is in memory, we may have
1357 to preserve temporaries. */
1358 preserve_temp_slots (last_expr_value);
1360 /* Free any temporaries used to evaluate this expression. Any temporary
1361 used as a result of this expression will already have been preserved
1368 /* Warn if EXP contains any computations whose results are not used.
1369 Return 1 if a warning is printed; 0 otherwise. */
1372 warn_if_unused_value (exp)
1375 if (TREE_USED (exp))
1378 switch (TREE_CODE (exp))
1380 case PREINCREMENT_EXPR:
1381 case POSTINCREMENT_EXPR:
1382 case PREDECREMENT_EXPR:
1383 case POSTDECREMENT_EXPR:
1388 case METHOD_CALL_EXPR:
1390 case WITH_CLEANUP_EXPR:
1392 /* We don't warn about COND_EXPR because it may be a useful
1393 construct if either arm contains a side effect. */
1398 /* For a binding, warn if no side effect within it. */
1399 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1401 case TRUTH_ORIF_EXPR:
1402 case TRUTH_ANDIF_EXPR:
1403 /* In && or ||, warn if 2nd operand has no side effect. */
1404 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1407 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
1409 /* Let people do `(foo (), 0)' without a warning. */
1410 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1412 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1416 case NON_LVALUE_EXPR:
1417 /* Don't warn about values cast to void. */
1418 if (TREE_TYPE (exp) == void_type_node)
1420 /* Don't warn about conversions not explicit in the user's program. */
1421 if (TREE_NO_UNUSED_WARNING (exp))
1423 /* Assignment to a cast usually results in a cast of a modify.
1424 Don't complain about that. */
1425 if (TREE_CODE (TREE_OPERAND (exp, 0)) == MODIFY_EXPR)
1427 /* Sometimes it results in a cast of a cast of a modify.
1428 Don't complain about that. */
1429 if ((TREE_CODE (TREE_OPERAND (exp, 0)) == CONVERT_EXPR
1430 || TREE_CODE (TREE_OPERAND (exp, 0)) == NOP_EXPR)
1431 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (exp, 0), 0)) == MODIFY_EXPR)
1435 /* Referencing a volatile value is a side effect, so don't warn. */
1436 if ((TREE_CODE_CLASS (TREE_CODE (exp)) == 'd'
1437 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1438 && TREE_THIS_VOLATILE (exp))
1440 warning_with_file_and_line (emit_filename, emit_lineno,
1441 "value computed is not used");
1446 /* Clear out the memory of the last expression evaluated. */
1454 /* Begin a statement which will return a value.
1455 Return the RTL_EXPR for this statement expr.
1456 The caller must save that value and pass it to expand_end_stmt_expr. */
1459 expand_start_stmt_expr ()
1461 /* Make the RTL_EXPR node temporary, not momentary,
1462 so that rtl_expr_chain doesn't become garbage. */
1463 int momentary = suspend_momentary ();
1464 tree t = make_node (RTL_EXPR);
1465 resume_momentary (momentary);
1468 expr_stmts_for_value++;
1472 /* Restore the previous state at the end of a statement that returns a value.
1473 Returns a tree node representing the statement's value and the
1474 insns to compute the value.
1476 The nodes of that expression have been freed by now, so we cannot use them.
1477 But we don't want to do that anyway; the expression has already been
1478 evaluated and now we just want to use the value. So generate a RTL_EXPR
1479 with the proper type and RTL value.
1481 If the last substatement was not an expression,
1482 return something with type `void'. */
1485 expand_end_stmt_expr (t)
1490 if (last_expr_type == 0)
1492 last_expr_type = void_type_node;
1493 last_expr_value = const0_rtx;
1495 else if (last_expr_value == 0)
1496 /* There are some cases where this can happen, such as when the
1497 statement is void type. */
1498 last_expr_value = const0_rtx;
1499 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
1500 /* Remove any possible QUEUED. */
1501 last_expr_value = protect_from_queue (last_expr_value, 0);
1505 TREE_TYPE (t) = last_expr_type;
1506 RTL_EXPR_RTL (t) = last_expr_value;
1507 RTL_EXPR_SEQUENCE (t) = get_insns ();
1509 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
1513 /* Don't consider deleting this expr or containing exprs at tree level. */
1514 TREE_SIDE_EFFECTS (t) = 1;
1515 /* Propagate volatility of the actual RTL expr. */
1516 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
1519 expr_stmts_for_value--;
1524 /* The exception handling nesting looks like this:
1527 { <-- exception handler block
1529 <-- in an exception handler
1531 : <-- in a TRY block
1532 : <-- in an exception handler
1537 : <-- in an except block
1538 : <-- in an exception handler
1545 /* Return nonzero iff in a try block at level LEVEL. */
1548 in_try_block (level)
1551 struct nesting *n = except_stack;
1554 while (n && n->data.except_stmt.after_label != 0)
1565 /* Return nonzero iff in an except block at level LEVEL. */
1568 in_except_block (level)
1571 struct nesting *n = except_stack;
1574 while (n && n->data.except_stmt.after_label == 0)
1585 /* Return nonzero iff in an exception handler at level LEVEL. */
1588 in_exception_handler (level)
1591 struct nesting *n = except_stack;
1592 while (n && level--)
1597 /* Record the fact that the current exception nesting raises
1598 exception EX. If not in an exception handler, return 0. */
1605 if (except_stack == 0)
1607 raises_ptr = &except_stack->data.except_stmt.raised;
1608 if (! value_member (ex, *raises_ptr))
1609 *raises_ptr = tree_cons (NULL_TREE, ex, *raises_ptr);
1613 /* Generate RTL for the start of a try block.
1615 TRY_CLAUSE is the condition to test to enter the try block. */
1618 expand_start_try (try_clause, exitflag, escapeflag)
1623 struct nesting *thishandler = ALLOC_NESTING ();
1625 /* Make an entry on cond_stack for the cond we are entering. */
1627 thishandler->next = except_stack;
1628 thishandler->all = nesting_stack;
1629 thishandler->depth = ++nesting_depth;
1630 thishandler->data.except_stmt.raised = 0;
1631 thishandler->data.except_stmt.handled = 0;
1632 thishandler->data.except_stmt.first_insn = get_insns ();
1633 thishandler->data.except_stmt.except_label = gen_label_rtx ();
1634 thishandler->data.except_stmt.unhandled_label = 0;
1635 thishandler->data.except_stmt.after_label = 0;
1636 thishandler->data.except_stmt.escape_label
1637 = escapeflag ? thishandler->data.except_stmt.except_label : 0;
1638 thishandler->exit_label = exitflag ? gen_label_rtx () : 0;
1639 except_stack = thishandler;
1640 nesting_stack = thishandler;
1642 do_jump (try_clause, thishandler->data.except_stmt.except_label, NULL_RTX);
1645 /* End of a TRY block. Nothing to do for now. */
1650 except_stack->data.except_stmt.after_label = gen_label_rtx ();
1651 expand_goto_internal (NULL_TREE, except_stack->data.except_stmt.after_label,
1655 /* Start an `except' nesting contour.
1656 EXITFLAG says whether this contour should be able to `exit' something.
1657 ESCAPEFLAG says whether this contour should be escapable. */
1660 expand_start_except (exitflag, escapeflag)
1667 /* An `exit' from catch clauses goes out to next exit level,
1668 if there is one. Otherwise, it just goes to the end
1669 of the construct. */
1670 for (n = except_stack->next; n; n = n->next)
1671 if (n->exit_label != 0)
1673 except_stack->exit_label = n->exit_label;
1677 except_stack->exit_label = except_stack->data.except_stmt.after_label;
1682 /* An `escape' from catch clauses goes out to next escape level,
1683 if there is one. Otherwise, it just goes to the end
1684 of the construct. */
1685 for (n = except_stack->next; n; n = n->next)
1686 if (n->data.except_stmt.escape_label != 0)
1688 except_stack->data.except_stmt.escape_label
1689 = n->data.except_stmt.escape_label;
1693 except_stack->data.except_stmt.escape_label
1694 = except_stack->data.except_stmt.after_label;
1696 do_pending_stack_adjust ();
1697 emit_label (except_stack->data.except_stmt.except_label);
1700 /* Generate code to `escape' from an exception contour. This
1701 is like `exiting', but does not conflict with constructs which
1704 Return nonzero if this contour is escapable, otherwise
1705 return zero, and language-specific code will emit the
1706 appropriate error message. */
1708 expand_escape_except ()
1712 for (n = except_stack; n; n = n->next)
1713 if (n->data.except_stmt.escape_label != 0)
1715 expand_goto_internal (NULL_TREE,
1716 n->data.except_stmt.escape_label, NULL_RTX);
1723 /* Finish processing and `except' contour.
1724 Culls out all exceptions which might be raise but not
1725 handled, and returns the list to the caller.
1726 Language-specific code is responsible for dealing with these
1730 expand_end_except ()
1733 tree raised = NULL_TREE;
1735 do_pending_stack_adjust ();
1736 emit_label (except_stack->data.except_stmt.after_label);
1738 n = except_stack->next;
1741 /* Propagate exceptions raised but not handled to next
1743 tree handled = except_stack->data.except_stmt.raised;
1744 if (handled != void_type_node)
1746 tree prev = NULL_TREE;
1747 raised = except_stack->data.except_stmt.raised;
1751 for (this_raise = raised, prev = 0; this_raise;
1752 this_raise = TREE_CHAIN (this_raise))
1754 if (value_member (TREE_VALUE (this_raise), handled))
1757 TREE_CHAIN (prev) = TREE_CHAIN (this_raise);
1760 raised = TREE_CHAIN (raised);
1761 if (raised == NULL_TREE)
1768 handled = TREE_CHAIN (handled);
1770 if (prev == NULL_TREE)
1773 TREE_CHAIN (prev) = n->data.except_stmt.raised;
1775 n->data.except_stmt.raised = raised;
1779 POPSTACK (except_stack);
1784 /* Record that exception EX is caught by this exception handler.
1785 Return nonzero if in exception handling construct, otherwise return 0. */
1792 if (except_stack == 0)
1794 raises_ptr = &except_stack->data.except_stmt.handled;
1795 if (*raises_ptr != void_type_node
1797 && ! value_member (ex, *raises_ptr))
1798 *raises_ptr = tree_cons (NULL_TREE, ex, *raises_ptr);
1802 /* Record that this exception handler catches all exceptions.
1803 Return nonzero if in exception handling construct, otherwise return 0. */
1806 expand_catch_default ()
1808 if (except_stack == 0)
1810 except_stack->data.except_stmt.handled = void_type_node;
1817 if (except_stack == 0 || except_stack->data.except_stmt.after_label == 0)
1819 expand_goto_internal (NULL_TREE, except_stack->data.except_stmt.after_label,
1824 /* Generate RTL for the start of an if-then. COND is the expression
1825 whose truth should be tested.
1827 If EXITFLAG is nonzero, this conditional is visible to
1828 `exit_something'. */
1831 expand_start_cond (cond, exitflag)
1835 struct nesting *thiscond = ALLOC_NESTING ();
1837 /* Make an entry on cond_stack for the cond we are entering. */
1839 thiscond->next = cond_stack;
1840 thiscond->all = nesting_stack;
1841 thiscond->depth = ++nesting_depth;
1842 thiscond->data.cond.next_label = gen_label_rtx ();
1843 /* Before we encounter an `else', we don't need a separate exit label
1844 unless there are supposed to be exit statements
1845 to exit this conditional. */
1846 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
1847 thiscond->data.cond.endif_label = thiscond->exit_label;
1848 cond_stack = thiscond;
1849 nesting_stack = thiscond;
1851 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
1854 /* Generate RTL between then-clause and the elseif-clause
1855 of an if-then-elseif-.... */
1858 expand_start_elseif (cond)
1861 if (cond_stack->data.cond.endif_label == 0)
1862 cond_stack->data.cond.endif_label = gen_label_rtx ();
1863 emit_jump (cond_stack->data.cond.endif_label);
1864 emit_label (cond_stack->data.cond.next_label);
1865 cond_stack->data.cond.next_label = gen_label_rtx ();
1866 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
1869 /* Generate RTL between the then-clause and the else-clause
1870 of an if-then-else. */
1873 expand_start_else ()
1875 if (cond_stack->data.cond.endif_label == 0)
1876 cond_stack->data.cond.endif_label = gen_label_rtx ();
1877 emit_jump (cond_stack->data.cond.endif_label);
1878 emit_label (cond_stack->data.cond.next_label);
1879 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
1882 /* Generate RTL for the end of an if-then.
1883 Pop the record for it off of cond_stack. */
1888 struct nesting *thiscond = cond_stack;
1890 do_pending_stack_adjust ();
1891 if (thiscond->data.cond.next_label)
1892 emit_label (thiscond->data.cond.next_label);
1893 if (thiscond->data.cond.endif_label)
1894 emit_label (thiscond->data.cond.endif_label);
1896 POPSTACK (cond_stack);
1900 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
1901 loop should be exited by `exit_something'. This is a loop for which
1902 `expand_continue' will jump to the top of the loop.
1904 Make an entry on loop_stack to record the labels associated with
1908 expand_start_loop (exit_flag)
1911 register struct nesting *thisloop = ALLOC_NESTING ();
1913 /* Make an entry on loop_stack for the loop we are entering. */
1915 thisloop->next = loop_stack;
1916 thisloop->all = nesting_stack;
1917 thisloop->depth = ++nesting_depth;
1918 thisloop->data.loop.start_label = gen_label_rtx ();
1919 thisloop->data.loop.end_label = gen_label_rtx ();
1920 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
1921 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
1922 loop_stack = thisloop;
1923 nesting_stack = thisloop;
1925 do_pending_stack_adjust ();
1927 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
1928 emit_label (thisloop->data.loop.start_label);
1933 /* Like expand_start_loop but for a loop where the continuation point
1934 (for expand_continue_loop) will be specified explicitly. */
1937 expand_start_loop_continue_elsewhere (exit_flag)
1940 struct nesting *thisloop = expand_start_loop (exit_flag);
1941 loop_stack->data.loop.continue_label = gen_label_rtx ();
1945 /* Specify the continuation point for a loop started with
1946 expand_start_loop_continue_elsewhere.
1947 Use this at the point in the code to which a continue statement
1951 expand_loop_continue_here ()
1953 do_pending_stack_adjust ();
1954 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
1955 emit_label (loop_stack->data.loop.continue_label);
1958 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
1959 Pop the block off of loop_stack. */
1964 register rtx insn = get_last_insn ();
1965 register rtx start_label = loop_stack->data.loop.start_label;
1966 rtx last_test_insn = 0;
1969 /* Mark the continue-point at the top of the loop if none elsewhere. */
1970 if (start_label == loop_stack->data.loop.continue_label)
1971 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
1973 do_pending_stack_adjust ();
1975 /* If optimizing, perhaps reorder the loop. If the loop
1976 starts with a conditional exit, roll that to the end
1977 where it will optimize together with the jump back.
1979 We look for the last conditional branch to the exit that we encounter
1980 before hitting 30 insns or a CALL_INSN. If we see an unconditional
1981 branch to the exit first, use it.
1983 We must also stop at NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes
1984 because moving them is not valid. */
1988 ! (GET_CODE (insn) == JUMP_INSN
1989 && GET_CODE (PATTERN (insn)) == SET
1990 && SET_DEST (PATTERN (insn)) == pc_rtx
1991 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
1993 /* Scan insns from the top of the loop looking for a qualified
1994 conditional exit. */
1995 for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
1996 insn = NEXT_INSN (insn))
1998 if (GET_CODE (insn) == CALL_INSN || GET_CODE (insn) == CODE_LABEL)
2001 if (GET_CODE (insn) == NOTE
2002 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2003 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2006 if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2009 if (last_test_insn && num_insns > 30)
2012 if (GET_CODE (insn) == JUMP_INSN && GET_CODE (PATTERN (insn)) == SET
2013 && SET_DEST (PATTERN (insn)) == pc_rtx
2014 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE
2015 && ((GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 1)) == LABEL_REF
2016 && (XEXP (XEXP (SET_SRC (PATTERN (insn)), 1), 0)
2017 == loop_stack->data.loop.end_label))
2018 || (GET_CODE (XEXP (SET_SRC (PATTERN (insn)), 2)) == LABEL_REF
2019 && (XEXP (XEXP (SET_SRC (PATTERN (insn)), 2), 0)
2020 == loop_stack->data.loop.end_label))))
2021 last_test_insn = insn;
2023 if (last_test_insn == 0 && GET_CODE (insn) == JUMP_INSN
2024 && GET_CODE (PATTERN (insn)) == SET
2025 && SET_DEST (PATTERN (insn)) == pc_rtx
2026 && GET_CODE (SET_SRC (PATTERN (insn))) == LABEL_REF
2027 && (XEXP (SET_SRC (PATTERN (insn)), 0)
2028 == loop_stack->data.loop.end_label))
2029 /* Include BARRIER. */
2030 last_test_insn = NEXT_INSN (insn);
2033 if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2035 /* We found one. Move everything from there up
2036 to the end of the loop, and add a jump into the loop
2037 to jump to there. */
2038 register rtx newstart_label = gen_label_rtx ();
2039 register rtx start_move = start_label;
2041 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2042 then we want to move this note also. */
2043 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2044 && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2045 == NOTE_INSN_LOOP_CONT))
2046 start_move = PREV_INSN (start_move);
2048 emit_label_after (newstart_label, PREV_INSN (start_move));
2049 reorder_insns (start_move, last_test_insn, get_last_insn ());
2050 emit_jump_insn_after (gen_jump (start_label),
2051 PREV_INSN (newstart_label));
2052 emit_barrier_after (PREV_INSN (newstart_label));
2053 start_label = newstart_label;
2057 emit_jump (start_label);
2058 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
2059 emit_label (loop_stack->data.loop.end_label);
2061 POPSTACK (loop_stack);
2066 /* Generate a jump to the current loop's continue-point.
2067 This is usually the top of the loop, but may be specified
2068 explicitly elsewhere. If not currently inside a loop,
2069 return 0 and do nothing; caller will print an error message. */
2072 expand_continue_loop (whichloop)
2073 struct nesting *whichloop;
2077 whichloop = loop_stack;
2080 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2085 /* Generate a jump to exit the current loop. If not currently inside a loop,
2086 return 0 and do nothing; caller will print an error message. */
2089 expand_exit_loop (whichloop)
2090 struct nesting *whichloop;
2094 whichloop = loop_stack;
2097 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2101 /* Generate a conditional jump to exit the current loop if COND
2102 evaluates to zero. If not currently inside a loop,
2103 return 0 and do nothing; caller will print an error message. */
2106 expand_exit_loop_if_false (whichloop, cond)
2107 struct nesting *whichloop;
2112 whichloop = loop_stack;
2115 do_jump (cond, whichloop->data.loop.end_label, NULL_RTX);
2119 /* Return non-zero if we should preserve sub-expressions as separate
2120 pseudos. We never do so if we aren't optimizing. We always do so
2121 if -fexpensive-optimizations.
2123 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2124 the loop may still be a small one. */
2127 preserve_subexpressions_p ()
2131 if (flag_expensive_optimizations)
2134 if (optimize == 0 || loop_stack == 0)
2137 insn = get_last_insn_anywhere ();
2140 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2141 < n_non_fixed_regs * 3));
2145 /* Generate a jump to exit the current loop, conditional, binding contour
2146 or case statement. Not all such constructs are visible to this function,
2147 only those started with EXIT_FLAG nonzero. Individual languages use
2148 the EXIT_FLAG parameter to control which kinds of constructs you can
2151 If not currently inside anything that can be exited,
2152 return 0 and do nothing; caller will print an error message. */
2155 expand_exit_something ()
2159 for (n = nesting_stack; n; n = n->all)
2160 if (n->exit_label != 0)
2162 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2169 /* Generate RTL to return from the current function, with no value.
2170 (That is, we do not do anything about returning any value.) */
2173 expand_null_return ()
2175 struct nesting *block = block_stack;
2178 /* Does any pending block have cleanups? */
2180 while (block && block->data.block.cleanups == 0)
2181 block = block->next;
2183 /* If yes, use a goto to return, since that runs cleanups. */
2185 expand_null_return_1 (last_insn, block != 0);
2188 /* Generate RTL to return from the current function, with value VAL. */
2191 expand_value_return (val)
2194 struct nesting *block = block_stack;
2195 rtx last_insn = get_last_insn ();
2196 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2198 /* Copy the value to the return location
2199 unless it's already there. */
2201 if (return_reg != val)
2203 #ifdef PROMOTE_FUNCTION_RETURN
2204 enum machine_mode mode = DECL_MODE (DECL_RESULT (current_function_decl));
2205 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2206 int unsignedp = TREE_UNSIGNED (type);
2208 if (TREE_CODE (type) == INTEGER_TYPE || TREE_CODE (type) == ENUMERAL_TYPE
2209 || TREE_CODE (type) == BOOLEAN_TYPE || TREE_CODE (type) == CHAR_TYPE
2210 || TREE_CODE (type) == REAL_TYPE || TREE_CODE (type) == POINTER_TYPE
2211 || TREE_CODE (type) == OFFSET_TYPE)
2213 PROMOTE_MODE (mode, unsignedp, type);
2216 if (GET_MODE (val) != VOIDmode && GET_MODE (val) != mode)
2217 convert_move (return_reg, val, unsignedp);
2220 emit_move_insn (return_reg, val);
2222 if (GET_CODE (return_reg) == REG
2223 && REGNO (return_reg) < FIRST_PSEUDO_REGISTER)
2224 emit_insn (gen_rtx (USE, VOIDmode, return_reg));
2226 /* Does any pending block have cleanups? */
2228 while (block && block->data.block.cleanups == 0)
2229 block = block->next;
2231 /* If yes, use a goto to return, since that runs cleanups.
2232 Use LAST_INSN to put cleanups *before* the move insn emitted above. */
2234 expand_null_return_1 (last_insn, block != 0);
2237 /* Output a return with no value. If LAST_INSN is nonzero,
2238 pretend that the return takes place after LAST_INSN.
2239 If USE_GOTO is nonzero then don't use a return instruction;
2240 go to the return label instead. This causes any cleanups
2241 of pending blocks to be executed normally. */
2244 expand_null_return_1 (last_insn, use_goto)
2248 rtx end_label = cleanup_label ? cleanup_label : return_label;
2250 clear_pending_stack_adjust ();
2251 do_pending_stack_adjust ();
2254 /* PCC-struct return always uses an epilogue. */
2255 if (current_function_returns_pcc_struct || use_goto)
2258 end_label = return_label = gen_label_rtx ();
2259 expand_goto_internal (NULL_TREE, end_label, last_insn);
2263 /* Otherwise output a simple return-insn if one is available,
2264 unless it won't do the job. */
2266 if (HAVE_return && use_goto == 0 && cleanup_label == 0)
2268 emit_jump_insn (gen_return ());
2274 /* Otherwise jump to the epilogue. */
2275 expand_goto_internal (NULL_TREE, end_label, last_insn);
2278 /* Generate RTL to evaluate the expression RETVAL and return it
2279 from the current function. */
2282 expand_return (retval)
2285 /* If there are any cleanups to be performed, then they will
2286 be inserted following LAST_INSN. It is desirable
2287 that the last_insn, for such purposes, should be the
2288 last insn before computing the return value. Otherwise, cleanups
2289 which call functions can clobber the return value. */
2290 /* ??? rms: I think that is erroneous, because in C++ it would
2291 run destructors on variables that might be used in the subsequent
2292 computation of the return value. */
2294 register rtx val = 0;
2298 struct nesting *block;
2300 /* If function wants no value, give it none. */
2301 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2303 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2305 expand_null_return ();
2309 /* Are any cleanups needed? E.g. C++ destructors to be run? */
2310 cleanups = any_pending_cleanups (1);
2312 if (TREE_CODE (retval) == RESULT_DECL)
2313 retval_rhs = retval;
2314 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2315 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2316 retval_rhs = TREE_OPERAND (retval, 1);
2317 else if (TREE_TYPE (retval) == void_type_node)
2318 /* Recognize tail-recursive call to void function. */
2319 retval_rhs = retval;
2321 retval_rhs = NULL_TREE;
2323 /* Only use `last_insn' if there are cleanups which must be run. */
2324 if (cleanups || cleanup_label != 0)
2325 last_insn = get_last_insn ();
2327 /* Distribute return down conditional expr if either of the sides
2328 may involve tail recursion (see test below). This enhances the number
2329 of tail recursions we see. Don't do this always since it can produce
2330 sub-optimal code in some cases and we distribute assignments into
2331 conditional expressions when it would help. */
2333 if (optimize && retval_rhs != 0
2334 && frame_offset == 0
2335 && TREE_CODE (retval_rhs) == COND_EXPR
2336 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
2337 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
2339 rtx label = gen_label_rtx ();
2340 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
2341 expand_return (build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2342 DECL_RESULT (current_function_decl),
2343 TREE_OPERAND (retval_rhs, 1)));
2345 expand_return (build (MODIFY_EXPR, TREE_TYPE (current_function_decl),
2346 DECL_RESULT (current_function_decl),
2347 TREE_OPERAND (retval_rhs, 2)));
2351 /* For tail-recursive call to current function,
2352 just jump back to the beginning.
2353 It's unsafe if any auto variable in this function
2354 has its address taken; for simplicity,
2355 require stack frame to be empty. */
2356 if (optimize && retval_rhs != 0
2357 && frame_offset == 0
2358 && TREE_CODE (retval_rhs) == CALL_EXPR
2359 && TREE_CODE (TREE_OPERAND (retval_rhs, 0)) == ADDR_EXPR
2360 && TREE_OPERAND (TREE_OPERAND (retval_rhs, 0), 0) == current_function_decl
2361 /* Finish checking validity, and if valid emit code
2362 to set the argument variables for the new call. */
2363 && tail_recursion_args (TREE_OPERAND (retval_rhs, 1),
2364 DECL_ARGUMENTS (current_function_decl)))
2366 if (tail_recursion_label == 0)
2368 tail_recursion_label = gen_label_rtx ();
2369 emit_label_after (tail_recursion_label,
2370 tail_recursion_reentry);
2373 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
2378 /* This optimization is safe if there are local cleanups
2379 because expand_null_return takes care of them.
2380 ??? I think it should also be safe when there is a cleanup label,
2381 because expand_null_return takes care of them, too.
2382 Any reason why not? */
2383 if (HAVE_return && cleanup_label == 0
2384 && ! current_function_returns_pcc_struct)
2386 /* If this is return x == y; then generate
2387 if (x == y) return 1; else return 0;
2388 if we can do it with explicit return insns. */
2390 switch (TREE_CODE (retval_rhs))
2398 case TRUTH_ANDIF_EXPR:
2399 case TRUTH_ORIF_EXPR:
2400 case TRUTH_AND_EXPR:
2402 case TRUTH_NOT_EXPR:
2403 case TRUTH_XOR_EXPR:
2404 op0 = gen_label_rtx ();
2405 jumpifnot (retval_rhs, op0);
2406 expand_value_return (const1_rtx);
2408 expand_value_return (const0_rtx);
2412 #endif /* HAVE_return */
2416 && TREE_TYPE (retval_rhs) != void_type_node
2417 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG)
2419 /* Calculate the return value into a pseudo reg. */
2420 val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2422 /* All temporaries have now been used. */
2424 /* Return the calculated value, doing cleanups first. */
2425 expand_value_return (val);
2429 /* No cleanups or no hard reg used;
2430 calculate value into hard return reg. */
2431 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2434 expand_value_return (DECL_RTL (DECL_RESULT (current_function_decl)));
2438 /* Return 1 if the end of the generated RTX is not a barrier.
2439 This means code already compiled can drop through. */
2442 drop_through_at_end_p ()
2444 rtx insn = get_last_insn ();
2445 while (insn && GET_CODE (insn) == NOTE)
2446 insn = PREV_INSN (insn);
2447 return insn && GET_CODE (insn) != BARRIER;
2450 /* Emit code to alter this function's formal parms for a tail-recursive call.
2451 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
2452 FORMALS is the chain of decls of formals.
2453 Return 1 if this can be done;
2454 otherwise return 0 and do not emit any code. */
2457 tail_recursion_args (actuals, formals)
2458 tree actuals, formals;
2460 register tree a = actuals, f = formals;
2462 register rtx *argvec;
2464 /* Check that number and types of actuals are compatible
2465 with the formals. This is not always true in valid C code.
2466 Also check that no formal needs to be addressable
2467 and that all formals are scalars. */
2469 /* Also count the args. */
2471 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
2473 if (TREE_TYPE (TREE_VALUE (a)) != TREE_TYPE (f))
2475 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
2478 if (a != 0 || f != 0)
2481 /* Compute all the actuals. */
2483 argvec = (rtx *) alloca (i * sizeof (rtx));
2485 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2486 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
2488 /* Find which actual values refer to current values of previous formals.
2489 Copy each of them now, before any formal is changed. */
2491 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
2495 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
2496 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
2497 { copy = 1; break; }
2499 argvec[i] = copy_to_reg (argvec[i]);
2502 /* Store the values of the actuals into the formals. */
2504 for (f = formals, a = actuals, i = 0; f;
2505 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
2507 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
2508 emit_move_insn (DECL_RTL (f), argvec[i]);
2510 convert_move (DECL_RTL (f), argvec[i],
2511 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
2518 /* Generate the RTL code for entering a binding contour.
2519 The variables are declared one by one, by calls to `expand_decl'.
2521 EXIT_FLAG is nonzero if this construct should be visible to
2522 `exit_something'. */
2525 expand_start_bindings (exit_flag)
2528 struct nesting *thisblock = ALLOC_NESTING ();
2530 rtx note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
2532 /* Make an entry on block_stack for the block we are entering. */
2534 thisblock->next = block_stack;
2535 thisblock->all = nesting_stack;
2536 thisblock->depth = ++nesting_depth;
2537 thisblock->data.block.stack_level = 0;
2538 thisblock->data.block.cleanups = 0;
2539 thisblock->data.block.function_call_count = 0;
2543 if (block_stack->data.block.cleanups == NULL_TREE
2544 && (block_stack->data.block.outer_cleanups == NULL_TREE
2545 || block_stack->data.block.outer_cleanups == empty_cleanup_list))
2546 thisblock->data.block.outer_cleanups = empty_cleanup_list;
2548 thisblock->data.block.outer_cleanups
2549 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2550 block_stack->data.block.outer_cleanups);
2553 thisblock->data.block.outer_cleanups = 0;
2557 && !(block_stack->data.block.cleanups == NULL_TREE
2558 && block_stack->data.block.outer_cleanups == NULL_TREE))
2559 thisblock->data.block.outer_cleanups
2560 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
2561 block_stack->data.block.outer_cleanups);
2563 thisblock->data.block.outer_cleanups = 0;
2565 thisblock->data.block.label_chain = 0;
2566 thisblock->data.block.innermost_stack_block = stack_block_stack;
2567 thisblock->data.block.first_insn = note;
2568 thisblock->data.block.block_start_count = ++block_start_count;
2569 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
2570 block_stack = thisblock;
2571 nesting_stack = thisblock;
2573 /* Make a new level for allocating stack slots. */
2577 /* Given a pointer to a BLOCK node, save a pointer to the most recently
2578 generated NOTE_INSN_BLOCK_END in the BLOCK_END_NOTE field of the given
2582 remember_end_note (block)
2583 register tree block;
2585 BLOCK_END_NOTE (block) = last_block_end_note;
2586 last_block_end_note = NULL_RTX;
2589 /* Generate RTL code to terminate a binding contour.
2590 VARS is the chain of VAR_DECL nodes
2591 for the variables bound in this contour.
2592 MARK_ENDS is nonzero if we should put a note at the beginning
2593 and end of this binding contour.
2595 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
2596 (That is true automatically if the contour has a saved stack level.) */
2599 expand_end_bindings (vars, mark_ends, dont_jump_in)
2604 register struct nesting *thisblock = block_stack;
2608 for (decl = vars; decl; decl = TREE_CHAIN (decl))
2609 if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL
2610 && ! DECL_IN_SYSTEM_HEADER (decl))
2611 warning_with_decl (decl, "unused variable `%s'");
2613 if (thisblock->exit_label)
2615 do_pending_stack_adjust ();
2616 emit_label (thisblock->exit_label);
2619 /* If necessary, make a handler for nonlocal gotos taking
2620 place in the function calls in this block. */
2621 if (function_call_count != thisblock->data.block.function_call_count
2623 /* Make handler for outermost block
2624 if there were any nonlocal gotos to this function. */
2625 && (thisblock->next == 0 ? current_function_has_nonlocal_label
2626 /* Make handler for inner block if it has something
2627 special to do when you jump out of it. */
2628 : (thisblock->data.block.cleanups != 0
2629 || thisblock->data.block.stack_level != 0)))
2632 rtx afterward = gen_label_rtx ();
2633 rtx handler_label = gen_label_rtx ();
2634 rtx save_receiver = gen_reg_rtx (Pmode);
2636 /* Don't let jump_optimize delete the handler. */
2637 LABEL_PRESERVE_P (handler_label) = 1;
2639 /* Record the handler address in the stack slot for that purpose,
2640 during this block, saving and restoring the outer value. */
2641 if (thisblock->next != 0)
2643 emit_move_insn (nonlocal_goto_handler_slot, save_receiver);
2644 emit_insn_before (gen_move_insn (save_receiver,
2645 nonlocal_goto_handler_slot),
2646 thisblock->data.block.first_insn);
2648 emit_insn_before (gen_move_insn (nonlocal_goto_handler_slot,
2649 gen_rtx (LABEL_REF, Pmode,
2651 thisblock->data.block.first_insn);
2653 /* Jump around the handler; it runs only when specially invoked. */
2654 emit_jump (afterward);
2655 emit_label (handler_label);
2657 #ifdef HAVE_nonlocal_goto
2658 if (! HAVE_nonlocal_goto)
2660 /* First adjust our frame pointer to its actual value. It was
2661 previously set to the start of the virtual area corresponding to
2662 the stacked variables when we branched here and now needs to be
2663 adjusted to the actual hardware fp value.
2665 Assignments are to virtual registers are converted by
2666 instantiate_virtual_regs into the corresponding assignment
2667 to the underlying register (fp in this case) that makes
2668 the original assignment true.
2669 So the following insn will actually be
2670 decrementing fp by STARTING_FRAME_OFFSET. */
2671 emit_move_insn (virtual_stack_vars_rtx, frame_pointer_rtx);
2673 #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM
2674 if (fixed_regs[ARG_POINTER_REGNUM])
2676 #ifdef ELIMINABLE_REGS
2677 /* If the argument pointer can be eliminated in favor of the
2678 frame pointer, we don't need to restore it. We assume here
2679 that if such an elimination is present, it can always be used.
2680 This is the case on all known machines; if we don't make this
2681 assumption, we do unnecessary saving on many machines. */
2682 static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
2685 for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
2686 if (elim_regs[i].from == ARG_POINTER_REGNUM
2687 && elim_regs[i].to == FRAME_POINTER_REGNUM)
2690 if (i == sizeof elim_regs / sizeof elim_regs [0])
2693 /* Now restore our arg pointer from the address at which it
2694 was saved in our stack frame.
2695 If there hasn't be space allocated for it yet, make
2697 if (arg_pointer_save_area == 0)
2698 arg_pointer_save_area
2699 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
2700 emit_move_insn (virtual_incoming_args_rtx,
2701 /* We need a pseudo here, or else
2702 instantiate_virtual_regs_1 complains. */
2703 copy_to_reg (arg_pointer_save_area));
2708 /* The handler expects the desired label address in the static chain
2709 register. It tests the address and does an appropriate jump
2710 to whatever label is desired. */
2711 for (link = nonlocal_labels; link; link = TREE_CHAIN (link))
2712 /* Skip any labels we shouldn't be able to jump to from here. */
2713 if (! DECL_TOO_LATE (TREE_VALUE (link)))
2715 rtx not_this = gen_label_rtx ();
2716 rtx this = gen_label_rtx ();
2717 do_jump_if_equal (static_chain_rtx,
2718 gen_rtx (LABEL_REF, Pmode, DECL_RTL (TREE_VALUE (link))),
2720 emit_jump (not_this);
2722 expand_goto (TREE_VALUE (link));
2723 emit_label (not_this);
2725 /* If label is not recognized, abort. */
2726 emit_library_call (gen_rtx (SYMBOL_REF, Pmode, "abort"), 0,
2728 emit_label (afterward);
2731 /* Don't allow jumping into a block that has cleanups or a stack level. */
2733 || thisblock->data.block.stack_level != 0
2734 || thisblock->data.block.cleanups != 0)
2736 struct label_chain *chain;
2738 /* Any labels in this block are no longer valid to go to.
2739 Mark them to cause an error message. */
2740 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
2742 DECL_TOO_LATE (chain->label) = 1;
2743 /* If any goto without a fixup came to this label,
2744 that must be an error, because gotos without fixups
2745 come from outside all saved stack-levels and all cleanups. */
2746 if (TREE_ADDRESSABLE (chain->label))
2747 error_with_decl (chain->label,
2748 "label `%s' used before containing binding contour");
2752 /* Restore stack level in effect before the block
2753 (only if variable-size objects allocated). */
2754 /* Perform any cleanups associated with the block. */
2756 if (thisblock->data.block.stack_level != 0
2757 || thisblock->data.block.cleanups != 0)
2759 /* Don't let cleanups affect ({...}) constructs. */
2760 int old_expr_stmts_for_value = expr_stmts_for_value;
2761 rtx old_last_expr_value = last_expr_value;
2762 tree old_last_expr_type = last_expr_type;
2763 expr_stmts_for_value = 0;
2765 /* Do the cleanups. */
2766 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE);
2767 do_pending_stack_adjust ();
2769 expr_stmts_for_value = old_expr_stmts_for_value;
2770 last_expr_value = old_last_expr_value;
2771 last_expr_type = old_last_expr_type;
2773 /* Restore the stack level. */
2775 if (thisblock->data.block.stack_level != 0)
2777 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
2778 thisblock->data.block.stack_level, NULL_RTX);
2779 if (nonlocal_goto_handler_slot != 0)
2780 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
2784 /* Any gotos out of this block must also do these things.
2785 Also report any gotos with fixups that came to labels in this
2787 fixup_gotos (thisblock,
2788 thisblock->data.block.stack_level,
2789 thisblock->data.block.cleanups,
2790 thisblock->data.block.first_insn,
2794 /* Mark the beginning and end of the scope if requested.
2795 We do this now, after running cleanups on the variables
2796 just going out of scope, so they are in scope for their cleanups. */
2799 last_block_end_note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
2801 /* Get rid of the beginning-mark if we don't make an end-mark. */
2802 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
2804 /* If doing stupid register allocation, make sure lives of all
2805 register variables declared here extend thru end of scope. */
2808 for (decl = vars; decl; decl = TREE_CHAIN (decl))
2810 rtx rtl = DECL_RTL (decl);
2811 if (TREE_CODE (decl) == VAR_DECL && rtl != 0)
2815 /* Restore block_stack level for containing block. */
2817 stack_block_stack = thisblock->data.block.innermost_stack_block;
2818 POPSTACK (block_stack);
2820 /* Pop the stack slot nesting and free any slots at this level. */
2824 /* Generate RTL for the automatic variable declaration DECL.
2825 (Other kinds of declarations are simply ignored if seen here.)
2826 CLEANUP is an expression to be executed at exit from this binding contour;
2827 for example, in C++, it might call the destructor for this variable.
2829 If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
2830 either before or after calling `expand_decl' but before compiling
2831 any subsequent expressions. This is because CLEANUP may be expanded
2832 more than once, on different branches of execution.
2833 For the same reason, CLEANUP may not contain a CALL_EXPR
2834 except as its topmost node--else `preexpand_calls' would get confused.
2836 If CLEANUP is nonzero and DECL is zero, we record a cleanup
2837 that is not associated with any particular variable.
2839 There is no special support here for C++ constructors.
2840 They should be handled by the proper code in DECL_INITIAL. */
2846 struct nesting *thisblock = block_stack;
2847 tree type = TREE_TYPE (decl);
2849 /* Only automatic variables need any expansion done.
2850 Static and external variables, and external functions,
2851 will be handled by `assemble_variable' (called from finish_decl).
2852 TYPE_DECL and CONST_DECL require nothing.
2853 PARM_DECLs are handled in `assign_parms'. */
2855 if (TREE_CODE (decl) != VAR_DECL)
2857 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
2860 /* Create the RTL representation for the variable. */
2862 if (type == error_mark_node)
2863 DECL_RTL (decl) = gen_rtx (MEM, BLKmode, const0_rtx);
2864 else if (DECL_SIZE (decl) == 0)
2865 /* Variable with incomplete type. */
2867 if (DECL_INITIAL (decl) == 0)
2868 /* Error message was already done; now avoid a crash. */
2869 DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
2871 /* An initializer is going to decide the size of this array.
2872 Until we know the size, represent its address with a reg. */
2873 DECL_RTL (decl) = gen_rtx (MEM, BLKmode, gen_reg_rtx (Pmode));
2875 else if (DECL_MODE (decl) != BLKmode
2876 /* If -ffloat-store, don't put explicit float vars
2878 && !(flag_float_store
2879 && TREE_CODE (type) == REAL_TYPE)
2880 && ! TREE_THIS_VOLATILE (decl)
2881 && ! TREE_ADDRESSABLE (decl)
2882 && (DECL_REGISTER (decl) || ! obey_regdecls))
2884 /* Automatic variable that can go in a register. */
2885 enum machine_mode reg_mode = DECL_MODE (decl);
2886 int unsignedp = TREE_UNSIGNED (type);
2888 if (TREE_CODE (type) == INTEGER_TYPE || TREE_CODE (type) == ENUMERAL_TYPE
2889 || TREE_CODE (type) == BOOLEAN_TYPE || TREE_CODE (type) == CHAR_TYPE
2890 || TREE_CODE (type) == REAL_TYPE || TREE_CODE (type) == POINTER_TYPE
2891 || TREE_CODE (type) == OFFSET_TYPE)
2893 PROMOTE_MODE (reg_mode, unsignedp, type);
2896 DECL_RTL (decl) = gen_reg_rtx (reg_mode);
2897 if (TREE_CODE (type) == POINTER_TYPE)
2898 mark_reg_pointer (DECL_RTL (decl));
2899 REG_USERVAR_P (DECL_RTL (decl)) = 1;
2901 else if (TREE_CODE (DECL_SIZE (decl)) == INTEGER_CST)
2903 /* Variable of fixed size that goes on the stack. */
2907 /* If we previously made RTL for this decl, it must be an array
2908 whose size was determined by the initializer.
2909 The old address was a register; set that register now
2910 to the proper address. */
2911 if (DECL_RTL (decl) != 0)
2913 if (GET_CODE (DECL_RTL (decl)) != MEM
2914 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
2916 oldaddr = XEXP (DECL_RTL (decl), 0);
2920 = assign_stack_temp (DECL_MODE (decl),
2921 ((TREE_INT_CST_LOW (DECL_SIZE (decl))
2922 + BITS_PER_UNIT - 1)
2926 /* Set alignment we actually gave this decl. */
2927 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
2928 : GET_MODE_BITSIZE (DECL_MODE (decl)));
2932 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
2933 if (addr != oldaddr)
2934 emit_move_insn (oldaddr, addr);
2937 /* If this is a memory ref that contains aggregate components,
2938 mark it as such for cse and loop optimize. */
2939 MEM_IN_STRUCT_P (DECL_RTL (decl))
2940 = (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
2941 || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
2942 || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
2943 || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE);
2945 /* If this is in memory because of -ffloat-store,
2946 set the volatile bit, to prevent optimizations from
2947 undoing the effects. */
2948 if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
2949 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
2953 /* Dynamic-size object: must push space on the stack. */
2957 /* Record the stack pointer on entry to block, if have
2958 not already done so. */
2959 if (thisblock->data.block.stack_level == 0)
2961 do_pending_stack_adjust ();
2962 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
2963 &thisblock->data.block.stack_level,
2964 thisblock->data.block.first_insn);
2965 stack_block_stack = thisblock;
2968 /* Compute the variable's size, in bytes. */
2969 size = expand_expr (size_binop (CEIL_DIV_EXPR,
2971 size_int (BITS_PER_UNIT)),
2972 NULL_RTX, VOIDmode, 0);
2975 /* This is equivalent to calling alloca. */
2976 current_function_calls_alloca = 1;
2978 /* Allocate space on the stack for the variable. */
2979 address = allocate_dynamic_stack_space (size, NULL_RTX,
2982 if (nonlocal_goto_handler_slot != 0)
2983 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level, NULL_RTX);
2985 /* Reference the variable indirect through that rtx. */
2986 DECL_RTL (decl) = gen_rtx (MEM, DECL_MODE (decl), address);
2988 /* If this is a memory ref that contains aggregate components,
2989 mark it as such for cse and loop optimize. */
2990 MEM_IN_STRUCT_P (DECL_RTL (decl))
2991 = (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
2992 || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
2993 || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
2994 || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE);
2996 /* Indicate the alignment we actually gave this variable. */
2997 #ifdef STACK_BOUNDARY
2998 DECL_ALIGN (decl) = STACK_BOUNDARY;
3000 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3004 if (TREE_THIS_VOLATILE (decl))
3005 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3006 #if 0 /* A variable is not necessarily unchanging
3007 just because it is const. RTX_UNCHANGING_P
3008 means no change in the function,
3009 not merely no change in the variable's scope.
3010 It is correct to set RTX_UNCHANGING_P if the variable's scope
3011 is the whole function. There's no convenient way to test that. */
3012 if (TREE_READONLY (decl))
3013 RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
3016 /* If doing stupid register allocation, make sure life of any
3017 register variable starts here, at the start of its scope. */
3020 use_variable (DECL_RTL (decl));
3023 /* Emit code to perform the initialization of a declaration DECL. */
3026 expand_decl_init (decl)
3029 int was_used = TREE_USED (decl);
3031 if (TREE_STATIC (decl))
3034 /* Compute and store the initial value now. */
3036 if (DECL_INITIAL (decl) == error_mark_node)
3038 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3039 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3040 || code == POINTER_TYPE)
3041 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3045 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3047 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
3048 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
3052 /* Don't let the initialization count as "using" the variable. */
3053 TREE_USED (decl) = was_used;
3055 /* Free any temporaries we made while initializing the decl. */
3059 /* CLEANUP is an expression to be executed at exit from this binding contour;
3060 for example, in C++, it might call the destructor for this variable.
3062 If CLEANUP contains any SAVE_EXPRs, then you must preevaluate them
3063 either before or after calling `expand_decl' but before compiling
3064 any subsequent expressions. This is because CLEANUP may be expanded
3065 more than once, on different branches of execution.
3066 For the same reason, CLEANUP may not contain a CALL_EXPR
3067 except as its topmost node--else `preexpand_calls' would get confused.
3069 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3070 that is not associated with any particular variable. */
3073 expand_decl_cleanup (decl, cleanup)
3076 struct nesting *thisblock = block_stack;
3078 /* Error if we are not in any block. */
3082 /* Record the cleanup if there is one. */
3086 thisblock->data.block.cleanups
3087 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
3088 /* If this block has a cleanup, it belongs in stack_block_stack. */
3089 stack_block_stack = thisblock;
3094 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
3095 DECL_ELTS is the list of elements that belong to DECL's type.
3096 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
3099 expand_anon_union_decl (decl, cleanup, decl_elts)
3100 tree decl, cleanup, decl_elts;
3102 struct nesting *thisblock = block_stack;
3105 expand_decl (decl, cleanup);
3106 x = DECL_RTL (decl);
3110 tree decl_elt = TREE_VALUE (decl_elts);
3111 tree cleanup_elt = TREE_PURPOSE (decl_elts);
3112 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
3114 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
3115 instead create a new MEM rtx with the proper mode. */
3116 if (GET_CODE (x) == MEM)
3118 if (mode == GET_MODE (x))
3119 DECL_RTL (decl_elt) = x;
3122 DECL_RTL (decl_elt) = gen_rtx (MEM, mode, copy_rtx (XEXP (x, 0)));
3123 MEM_IN_STRUCT_P (DECL_RTL (decl_elt)) = MEM_IN_STRUCT_P (x);
3124 RTX_UNCHANGING_P (DECL_RTL (decl_elt)) = RTX_UNCHANGING_P (x);
3127 else if (GET_CODE (x) == REG)
3129 if (mode == GET_MODE (x))
3130 DECL_RTL (decl_elt) = x;
3132 DECL_RTL (decl_elt) = gen_rtx (SUBREG, mode, x, 0);
3137 /* Record the cleanup if there is one. */
3140 thisblock->data.block.cleanups
3141 = temp_tree_cons (decl_elt, cleanup_elt,
3142 thisblock->data.block.cleanups);
3144 decl_elts = TREE_CHAIN (decl_elts);
3148 /* Expand a list of cleanups LIST.
3149 Elements may be expressions or may be nested lists.
3151 If DONT_DO is nonnull, then any list-element
3152 whose TREE_PURPOSE matches DONT_DO is omitted.
3153 This is sometimes used to avoid a cleanup associated with
3154 a value that is being returned out of the scope. */
3157 expand_cleanups (list, dont_do)
3162 for (tail = list; tail; tail = TREE_CHAIN (tail))
3163 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
3165 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
3166 expand_cleanups (TREE_VALUE (tail), dont_do);
3169 /* Cleanups may be run multiple times. For example,
3170 when exiting a binding contour, we expand the
3171 cleanups associated with that contour. When a goto
3172 within that binding contour has a target outside that
3173 contour, it will expand all cleanups from its scope to
3174 the target. Though the cleanups are expanded multiple
3175 times, the control paths are non-overlapping so the
3176 cleanups will not be executed twice. */
3177 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
3183 /* Move all cleanups from the current block_stack
3184 to the containing block_stack, where they are assumed to
3185 have been created. If anything can cause a temporary to
3186 be created, but not expanded for more than one level of
3187 block_stacks, then this code will have to change. */
3192 struct nesting *block = block_stack;
3193 struct nesting *outer = block->next;
3195 outer->data.block.cleanups
3196 = chainon (block->data.block.cleanups,
3197 outer->data.block.cleanups);
3198 block->data.block.cleanups = 0;
3202 last_cleanup_this_contour ()
3204 if (block_stack == 0)
3207 return block_stack->data.block.cleanups;
3210 /* Return 1 if there are any pending cleanups at this point.
3211 If THIS_CONTOUR is nonzero, check the current contour as well.
3212 Otherwise, look only at the contours that enclose this one. */
3215 any_pending_cleanups (this_contour)
3218 struct nesting *block;
3220 if (block_stack == 0)
3223 if (this_contour && block_stack->data.block.cleanups != NULL)
3225 if (block_stack->data.block.cleanups == 0
3226 && (block_stack->data.block.outer_cleanups == 0
3228 || block_stack->data.block.outer_cleanups == empty_cleanup_list
3233 for (block = block_stack->next; block; block = block->next)
3234 if (block->data.block.cleanups != 0)
3240 /* Enter a case (Pascal) or switch (C) statement.
3241 Push a block onto case_stack and nesting_stack
3242 to accumulate the case-labels that are seen
3243 and to record the labels generated for the statement.
3245 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
3246 Otherwise, this construct is transparent for `exit_something'.
3248 EXPR is the index-expression to be dispatched on.
3249 TYPE is its nominal type. We could simply convert EXPR to this type,
3250 but instead we take short cuts. */
3253 expand_start_case (exit_flag, expr, type, printname)
3259 register struct nesting *thiscase = ALLOC_NESTING ();
3261 /* Make an entry on case_stack for the case we are entering. */
3263 thiscase->next = case_stack;
3264 thiscase->all = nesting_stack;
3265 thiscase->depth = ++nesting_depth;
3266 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
3267 thiscase->data.case_stmt.case_list = 0;
3268 thiscase->data.case_stmt.index_expr = expr;
3269 thiscase->data.case_stmt.nominal_type = type;
3270 thiscase->data.case_stmt.default_label = 0;
3271 thiscase->data.case_stmt.num_ranges = 0;
3272 thiscase->data.case_stmt.printname = printname;
3273 thiscase->data.case_stmt.seenlabel = 0;
3274 case_stack = thiscase;
3275 nesting_stack = thiscase;
3277 do_pending_stack_adjust ();
3279 /* Make sure case_stmt.start points to something that won't
3280 need any transformation before expand_end_case. */
3281 if (GET_CODE (get_last_insn ()) != NOTE)
3282 emit_note (NULL_PTR, NOTE_INSN_DELETED);
3284 thiscase->data.case_stmt.start = get_last_insn ();
3287 /* Start a "dummy case statement" within which case labels are invalid
3288 and are not connected to any larger real case statement.
3289 This can be used if you don't want to let a case statement jump
3290 into the middle of certain kinds of constructs. */
3293 expand_start_case_dummy ()
3295 register struct nesting *thiscase = ALLOC_NESTING ();
3297 /* Make an entry on case_stack for the dummy. */
3299 thiscase->next = case_stack;
3300 thiscase->all = nesting_stack;
3301 thiscase->depth = ++nesting_depth;
3302 thiscase->exit_label = 0;
3303 thiscase->data.case_stmt.case_list = 0;
3304 thiscase->data.case_stmt.start = 0;
3305 thiscase->data.case_stmt.nominal_type = 0;
3306 thiscase->data.case_stmt.default_label = 0;
3307 thiscase->data.case_stmt.num_ranges = 0;
3308 case_stack = thiscase;
3309 nesting_stack = thiscase;
3312 /* End a dummy case statement. */
3315 expand_end_case_dummy ()
3317 POPSTACK (case_stack);
3320 /* Return the data type of the index-expression
3321 of the innermost case statement, or null if none. */
3324 case_index_expr_type ()
3327 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
3331 /* Accumulate one case or default label inside a case or switch statement.
3332 VALUE is the value of the case (a null pointer, for a default label).
3334 If not currently inside a case or switch statement, return 1 and do
3335 nothing. The caller will print a language-specific error message.
3336 If VALUE is a duplicate or overlaps, return 2 and do nothing
3337 except store the (first) duplicate node in *DUPLICATE.
3338 If VALUE is out of range, return 3 and do nothing.
3339 If we are jumping into the scope of a cleaup or var-sized array, return 5.
3340 Return 0 on success.
3342 Extended to handle range statements. */
3345 pushcase (value, label, duplicate)
3346 register tree value;
3347 register tree label;
3350 register struct case_node **l;
3351 register struct case_node *n;
3355 /* Fail if not inside a real case statement. */
3356 if (! (case_stack && case_stack->data.case_stmt.start))
3359 if (stack_block_stack
3360 && stack_block_stack->depth > case_stack->depth)
3363 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3364 nominal_type = case_stack->data.case_stmt.nominal_type;
3366 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3367 if (index_type == error_mark_node)
3370 /* Convert VALUE to the type in which the comparisons are nominally done. */
3372 value = convert (nominal_type, value);
3374 /* If this is the first label, warn if any insns have been emitted. */
3375 if (case_stack->data.case_stmt.seenlabel == 0)
3378 for (insn = case_stack->data.case_stmt.start;
3380 insn = NEXT_INSN (insn))
3382 if (GET_CODE (insn) == CODE_LABEL)
3384 if (GET_CODE (insn) != NOTE
3385 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
3387 warning ("unreachable code at beginning of %s",
3388 case_stack->data.case_stmt.printname);
3393 case_stack->data.case_stmt.seenlabel = 1;
3395 /* Fail if this value is out of range for the actual type of the index
3396 (which may be narrower than NOMINAL_TYPE). */
3397 if (value != 0 && ! int_fits_type_p (value, index_type))
3400 /* Fail if this is a duplicate or overlaps another entry. */
3403 if (case_stack->data.case_stmt.default_label != 0)
3405 *duplicate = case_stack->data.case_stmt.default_label;
3408 case_stack->data.case_stmt.default_label = label;
3412 /* Find the elt in the chain before which to insert the new value,
3413 to keep the chain sorted in increasing order.
3414 But report an error if this element is a duplicate. */
3415 for (l = &case_stack->data.case_stmt.case_list;
3416 /* Keep going past elements distinctly less than VALUE. */
3417 *l != 0 && tree_int_cst_lt ((*l)->high, value);
3422 /* Element we will insert before must be distinctly greater;
3423 overlap means error. */
3424 if (! tree_int_cst_lt (value, (*l)->low))
3426 *duplicate = (*l)->code_label;
3431 /* Add this label to the chain, and succeed.
3432 Copy VALUE so it is on temporary rather than momentary
3433 obstack and will thus survive till the end of the case statement. */
3434 n = (struct case_node *) oballoc (sizeof (struct case_node));
3437 n->high = n->low = copy_node (value);
3438 n->code_label = label;
3442 expand_label (label);
3446 /* Like pushcase but this case applies to all values
3447 between VALUE1 and VALUE2 (inclusive).
3448 The return value is the same as that of pushcase
3449 but there is one additional error code:
3450 4 means the specified range was empty. */
3453 pushcase_range (value1, value2, label, duplicate)
3454 register tree value1, value2;
3455 register tree label;
3458 register struct case_node **l;
3459 register struct case_node *n;
3463 /* Fail if not inside a real case statement. */
3464 if (! (case_stack && case_stack->data.case_stmt.start))
3467 if (stack_block_stack
3468 && stack_block_stack->depth > case_stack->depth)
3471 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
3472 nominal_type = case_stack->data.case_stmt.nominal_type;
3474 /* If the index is erroneous, avoid more problems: pretend to succeed. */
3475 if (index_type == error_mark_node)
3478 /* If this is the first label, warn if any insns have been emitted. */
3479 if (case_stack->data.case_stmt.seenlabel == 0)
3482 for (insn = case_stack->data.case_stmt.start;
3484 insn = NEXT_INSN (insn))
3486 if (GET_CODE (insn) == CODE_LABEL)
3488 if (GET_CODE (insn) != NOTE
3489 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
3491 warning ("unreachable code at beginning of %s",
3492 case_stack->data.case_stmt.printname);
3497 case_stack->data.case_stmt.seenlabel = 1;
3499 /* Convert VALUEs to type in which the comparisons are nominally done. */
3500 if (value1 == 0) /* Negative infinity. */
3501 value1 = TYPE_MIN_VALUE(index_type);
3502 value1 = convert (nominal_type, value1);
3504 if (value2 == 0) /* Positive infinity. */
3505 value2 = TYPE_MAX_VALUE(index_type);
3506 value2 = convert (nominal_type, value2);
3508 /* Fail if these values are out of range. */
3509 if (! int_fits_type_p (value1, index_type))
3512 if (! int_fits_type_p (value2, index_type))
3515 /* Fail if the range is empty. */
3516 if (tree_int_cst_lt (value2, value1))
3519 /* If the bounds are equal, turn this into the one-value case. */
3520 if (tree_int_cst_equal (value1, value2))
3521 return pushcase (value1, label, duplicate);
3523 /* Find the elt in the chain before which to insert the new value,
3524 to keep the chain sorted in increasing order.
3525 But report an error if this element is a duplicate. */
3526 for (l = &case_stack->data.case_stmt.case_list;
3527 /* Keep going past elements distinctly less than this range. */
3528 *l != 0 && tree_int_cst_lt ((*l)->high, value1);
3533 /* Element we will insert before must be distinctly greater;
3534 overlap means error. */
3535 if (! tree_int_cst_lt (value2, (*l)->low))
3537 *duplicate = (*l)->code_label;
3542 /* Add this label to the chain, and succeed.
3543 Copy VALUE1, VALUE2 so they are on temporary rather than momentary
3544 obstack and will thus survive till the end of the case statement. */
3546 n = (struct case_node *) oballoc (sizeof (struct case_node));
3549 n->low = copy_node (value1);
3550 n->high = copy_node (value2);
3551 n->code_label = label;
3554 expand_label (label);
3556 case_stack->data.case_stmt.num_ranges++;
3561 /* Called when the index of a switch statement is an enumerated type
3562 and there is no default label.
3564 Checks that all enumeration literals are covered by the case
3565 expressions of a switch. Also, warn if there are any extra
3566 switch cases that are *not* elements of the enumerated type.
3568 If all enumeration literals were covered by the case expressions,
3569 turn one of the expressions into the default expression since it should
3570 not be possible to fall through such a switch. */
3573 check_for_full_enumeration_handling (type)
3576 register struct case_node *n;
3577 register struct case_node **l;
3578 register tree chain;
3581 /* The time complexity of this loop is currently O(N * M), with
3582 N being the number of members in the enumerated type, and
3583 M being the number of case expressions in the switch. */
3585 for (chain = TYPE_VALUES (type);
3587 chain = TREE_CHAIN (chain))
3589 /* Find a match between enumeral and case expression, if possible.
3590 Quit looking when we've gone too far (since case expressions
3591 are kept sorted in ascending order). Warn about enumerators not
3592 handled in the switch statement case expression list. */
3594 for (n = case_stack->data.case_stmt.case_list;
3595 n && tree_int_cst_lt (n->high, TREE_VALUE (chain));
3599 if (!n || tree_int_cst_lt (TREE_VALUE (chain), n->low))
3602 warning ("enumeration value `%s' not handled in switch",
3603 IDENTIFIER_POINTER (TREE_PURPOSE (chain)));
3608 /* Now we go the other way around; we warn if there are case
3609 expressions that don't correspond to enumerators. This can
3610 occur since C and C++ don't enforce type-checking of
3611 assignments to enumeration variables. */
3614 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
3616 for (chain = TYPE_VALUES (type);
3617 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
3618 chain = TREE_CHAIN (chain))
3623 if (TYPE_NAME (type) == 0)
3624 warning ("case value `%d' not in enumerated type",
3625 TREE_INT_CST_LOW (n->low));
3627 warning ("case value `%d' not in enumerated type `%s'",
3628 TREE_INT_CST_LOW (n->low),
3629 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
3632 : DECL_NAME (TYPE_NAME (type))));
3634 if (!tree_int_cst_equal (n->low, n->high))
3636 for (chain = TYPE_VALUES (type);
3637 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
3638 chain = TREE_CHAIN (chain))
3643 if (TYPE_NAME (type) == 0)
3644 warning ("case value `%d' not in enumerated type",
3645 TREE_INT_CST_LOW (n->high));
3647 warning ("case value `%d' not in enumerated type `%s'",
3648 TREE_INT_CST_LOW (n->high),
3649 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
3652 : DECL_NAME (TYPE_NAME (type))));
3658 /* ??? This optimization is disabled because it causes valid programs to
3659 fail. ANSI C does not guarantee that an expression with enum type
3660 will have a value that is the same as one of the enumation literals. */
3662 /* If all values were found as case labels, make one of them the default
3663 label. Thus, this switch will never fall through. We arbitrarily pick
3664 the last one to make the default since this is likely the most
3665 efficient choice. */
3669 for (l = &case_stack->data.case_stmt.case_list;
3674 case_stack->data.case_stmt.default_label = (*l)->code_label;
3680 /* Terminate a case (Pascal) or switch (C) statement
3681 in which ORIG_INDEX is the expression to be tested.
3682 Generate the code to test it and jump to the right place. */
3685 expand_end_case (orig_index)
3688 tree minval, maxval, range, orig_minval;
3689 rtx default_label = 0;
3690 register struct case_node *n;
3693 rtx table_label = gen_label_rtx ();
3698 register struct nesting *thiscase = case_stack;
3699 tree index_expr = thiscase->data.case_stmt.index_expr;
3700 int unsignedp = TREE_UNSIGNED (TREE_TYPE (index_expr));
3702 do_pending_stack_adjust ();
3704 /* An ERROR_MARK occurs for various reasons including invalid data type. */
3705 if (TREE_TYPE (index_expr) != error_mark_node)
3707 /* If switch expression was an enumerated type, check that all
3708 enumeration literals are covered by the cases.
3709 No sense trying this if there's a default case, however. */
3711 if (!thiscase->data.case_stmt.default_label
3712 && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
3713 && TREE_CODE (index_expr) != INTEGER_CST)
3714 check_for_full_enumeration_handling (TREE_TYPE (orig_index));
3716 /* If this is the first label, warn if any insns have been emitted. */
3717 if (thiscase->data.case_stmt.seenlabel == 0)
3720 for (insn = get_last_insn ();
3721 insn != case_stack->data.case_stmt.start;
3722 insn = PREV_INSN (insn))
3723 if (GET_CODE (insn) != NOTE
3724 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn))!= USE))
3726 warning ("unreachable code at beginning of %s",
3727 case_stack->data.case_stmt.printname);
3732 /* If we don't have a default-label, create one here,
3733 after the body of the switch. */
3734 if (thiscase->data.case_stmt.default_label == 0)
3736 thiscase->data.case_stmt.default_label
3737 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
3738 expand_label (thiscase->data.case_stmt.default_label);
3740 default_label = label_rtx (thiscase->data.case_stmt.default_label);
3742 before_case = get_last_insn ();
3744 /* Simplify the case-list before we count it. */
3745 group_case_nodes (thiscase->data.case_stmt.case_list);
3747 /* Get upper and lower bounds of case values.
3748 Also convert all the case values to the index expr's data type. */
3751 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
3753 /* Check low and high label values are integers. */
3754 if (TREE_CODE (n->low) != INTEGER_CST)
3756 if (TREE_CODE (n->high) != INTEGER_CST)
3759 n->low = convert (TREE_TYPE (index_expr), n->low);
3760 n->high = convert (TREE_TYPE (index_expr), n->high);
3762 /* Count the elements and track the largest and smallest
3763 of them (treating them as signed even if they are not). */
3771 if (INT_CST_LT (n->low, minval))
3773 if (INT_CST_LT (maxval, n->high))
3776 /* A range counts double, since it requires two compares. */
3777 if (! tree_int_cst_equal (n->low, n->high))
3781 orig_minval = minval;
3783 /* Compute span of values. */
3785 range = fold (build (MINUS_EXPR, TREE_TYPE (index_expr),
3788 if (count == 0 || TREE_CODE (TREE_TYPE (index_expr)) == ERROR_MARK)
3790 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
3792 emit_jump (default_label);
3795 /* If range of values is much bigger than number of values,
3796 make a sequence of conditional branches instead of a dispatch.
3797 If the switch-index is a constant, do it this way
3798 because we can optimize it. */
3800 #ifndef CASE_VALUES_THRESHOLD
3802 #define CASE_VALUES_THRESHOLD (HAVE_casesi ? 4 : 5)
3804 /* If machine does not have a case insn that compares the
3805 bounds, this means extra overhead for dispatch tables
3806 which raises the threshold for using them. */
3807 #define CASE_VALUES_THRESHOLD 5
3808 #endif /* HAVE_casesi */
3809 #endif /* CASE_VALUES_THRESHOLD */
3811 else if (TREE_INT_CST_HIGH (range) != 0
3812 || count < CASE_VALUES_THRESHOLD
3813 || ((unsigned HOST_WIDE_INT) (TREE_INT_CST_LOW (range))
3815 || TREE_CODE (index_expr) == INTEGER_CST
3816 /* These will reduce to a constant. */
3817 || (TREE_CODE (index_expr) == CALL_EXPR
3818 && TREE_CODE (TREE_OPERAND (index_expr, 0)) == ADDR_EXPR
3819 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == FUNCTION_DECL
3820 && DECL_FUNCTION_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_CLASSIFY_TYPE)
3821 || (TREE_CODE (index_expr) == COMPOUND_EXPR
3822 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
3824 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
3826 /* If the index is a short or char that we do not have
3827 an insn to handle comparisons directly, convert it to
3828 a full integer now, rather than letting each comparison
3829 generate the conversion. */
3831 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
3832 && (cmp_optab->handlers[(int) GET_MODE(index)].insn_code
3833 == CODE_FOR_nothing))
3835 enum machine_mode wider_mode;
3836 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
3837 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
3838 if (cmp_optab->handlers[(int) wider_mode].insn_code
3839 != CODE_FOR_nothing)
3841 index = convert_to_mode (wider_mode, index, unsignedp);
3847 do_pending_stack_adjust ();
3849 index = protect_from_queue (index, 0);
3850 if (GET_CODE (index) == MEM)
3851 index = copy_to_reg (index);
3852 if (GET_CODE (index) == CONST_INT
3853 || TREE_CODE (index_expr) == INTEGER_CST)
3855 /* Make a tree node with the proper constant value
3856 if we don't already have one. */
3857 if (TREE_CODE (index_expr) != INTEGER_CST)
3860 = build_int_2 (INTVAL (index),
3861 !unsignedp && INTVAL (index) >= 0 ? 0 : -1);
3862 index_expr = convert (TREE_TYPE (index_expr), index_expr);
3865 /* For constant index expressions we need only
3866 issue a unconditional branch to the appropriate
3867 target code. The job of removing any unreachable
3868 code is left to the optimisation phase if the
3869 "-O" option is specified. */
3870 for (n = thiscase->data.case_stmt.case_list;
3874 if (! tree_int_cst_lt (index_expr, n->low)
3875 && ! tree_int_cst_lt (n->high, index_expr))
3879 emit_jump (label_rtx (n->code_label));
3881 emit_jump (default_label);
3885 /* If the index expression is not constant we generate
3886 a binary decision tree to select the appropriate
3887 target code. This is done as follows:
3889 The list of cases is rearranged into a binary tree,
3890 nearly optimal assuming equal probability for each case.
3892 The tree is transformed into RTL, eliminating
3893 redundant test conditions at the same time.
3895 If program flow could reach the end of the
3896 decision tree an unconditional jump to the
3897 default code is emitted. */
3900 = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
3901 && estimate_case_costs (thiscase->data.case_stmt.case_list));
3902 balance_case_nodes (&thiscase->data.case_stmt.case_list,
3904 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
3905 default_label, TREE_TYPE (index_expr));
3906 emit_jump_if_reachable (default_label);
3915 enum machine_mode index_mode = SImode;
3916 int index_bits = GET_MODE_BITSIZE (index_mode);
3918 /* Convert the index to SImode. */
3919 if (GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (index_expr)))
3920 > GET_MODE_BITSIZE (index_mode))
3922 enum machine_mode omode = TYPE_MODE (TREE_TYPE (index_expr));
3923 rtx rangertx = expand_expr (range, NULL_RTX, VOIDmode, 0);
3925 /* We must handle the endpoints in the original mode. */
3926 index_expr = build (MINUS_EXPR, TREE_TYPE (index_expr),
3927 index_expr, minval);
3928 minval = integer_zero_node;
3929 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
3930 emit_cmp_insn (rangertx, index, LTU, NULL_RTX, omode, 1, 0);
3931 emit_jump_insn (gen_bltu (default_label));
3932 /* Now we can safely truncate. */
3933 index = convert_to_mode (index_mode, index, 0);
3937 if (TYPE_MODE (TREE_TYPE (index_expr)) != index_mode)
3938 index_expr = convert (type_for_size (index_bits, 0),
3940 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
3943 index = protect_from_queue (index, 0);
3944 do_pending_stack_adjust ();
3946 emit_jump_insn (gen_casesi (index, expand_expr (minval, NULL_RTX,
3948 expand_expr (range, NULL_RTX,
3950 table_label, default_label));
3954 #ifdef HAVE_tablejump
3955 if (! win && HAVE_tablejump)
3957 index_expr = convert (thiscase->data.case_stmt.nominal_type,
3958 fold (build (MINUS_EXPR,
3959 TREE_TYPE (index_expr),
3960 index_expr, minval)));
3961 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
3963 index = protect_from_queue (index, 0);
3964 do_pending_stack_adjust ();
3966 do_tablejump (index, TYPE_MODE (TREE_TYPE (index_expr)),
3967 expand_expr (range, NULL_RTX, VOIDmode, 0),
3968 table_label, default_label);
3975 /* Get table of labels to jump to, in order of case index. */
3977 ncases = TREE_INT_CST_LOW (range) + 1;
3978 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
3979 bzero (labelvec, ncases * sizeof (rtx));
3981 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
3983 register HOST_WIDE_INT i
3984 = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
3989 = gen_rtx (LABEL_REF, Pmode, label_rtx (n->code_label));
3990 if (i + TREE_INT_CST_LOW (orig_minval)
3991 == TREE_INT_CST_LOW (n->high))
3997 /* Fill in the gaps with the default. */
3998 for (i = 0; i < ncases; i++)
3999 if (labelvec[i] == 0)
4000 labelvec[i] = gen_rtx (LABEL_REF, Pmode, default_label);
4002 /* Output the table */
4003 emit_label (table_label);
4005 /* This would be a lot nicer if CASE_VECTOR_PC_RELATIVE
4006 were an expression, instead of an #ifdef/#ifndef. */
4008 #ifdef CASE_VECTOR_PC_RELATIVE
4012 emit_jump_insn (gen_rtx (ADDR_DIFF_VEC, CASE_VECTOR_MODE,
4013 gen_rtx (LABEL_REF, Pmode, table_label),
4014 gen_rtvec_v (ncases, labelvec)));
4016 emit_jump_insn (gen_rtx (ADDR_VEC, CASE_VECTOR_MODE,
4017 gen_rtvec_v (ncases, labelvec)));
4019 /* If the case insn drops through the table,
4020 after the table we must jump to the default-label.
4021 Otherwise record no drop-through after the table. */
4022 #ifdef CASE_DROPS_THROUGH
4023 emit_jump (default_label);
4029 before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
4030 reorder_insns (before_case, get_last_insn (),
4031 thiscase->data.case_stmt.start);
4033 if (thiscase->exit_label)
4034 emit_label (thiscase->exit_label);
4036 POPSTACK (case_stack);
4041 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
4044 do_jump_if_equal (op1, op2, label, unsignedp)
4045 rtx op1, op2, label;
4048 if (GET_CODE (op1) == CONST_INT
4049 && GET_CODE (op2) == CONST_INT)
4051 if (INTVAL (op1) == INTVAL (op2))
4056 enum machine_mode mode = GET_MODE (op1);
4057 if (mode == VOIDmode)
4058 mode = GET_MODE (op2);
4059 emit_cmp_insn (op1, op2, EQ, NULL_RTX, mode, unsignedp, 0);
4060 emit_jump_insn (gen_beq (label));
4064 /* Not all case values are encountered equally. This function
4065 uses a heuristic to weight case labels, in cases where that
4066 looks like a reasonable thing to do.
4068 Right now, all we try to guess is text, and we establish the
4071 chars above space: 16
4080 If we find any cases in the switch that are not either -1 or in the range
4081 of valid ASCII characters, or are control characters other than those
4082 commonly used with "\", don't treat this switch scanning text.
4084 Return 1 if these nodes are suitable for cost estimation, otherwise
4088 estimate_case_costs (node)
4091 tree min_ascii = build_int_2 (-1, -1);
4092 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
4096 /* If we haven't already made the cost table, make it now. Note that the
4097 lower bound of the table is -1, not zero. */
4099 if (cost_table == NULL)
4101 cost_table = ((short *) xmalloc (129 * sizeof (short))) + 1;
4102 bzero (cost_table - 1, 129 * sizeof (short));
4104 for (i = 0; i < 128; i++)
4108 else if (ispunct (i))
4110 else if (iscntrl (i))
4114 cost_table[' '] = 8;
4115 cost_table['\t'] = 4;
4116 cost_table['\0'] = 4;
4117 cost_table['\n'] = 2;
4118 cost_table['\f'] = 1;
4119 cost_table['\v'] = 1;
4120 cost_table['\b'] = 1;
4123 /* See if all the case expressions look like text. It is text if the
4124 constant is >= -1 and the highest constant is <= 127. Do all comparisons
4125 as signed arithmetic since we don't want to ever access cost_table with a
4126 value less than -1. Also check that none of the constants in a range
4127 are strange control characters. */
4129 for (n = node; n; n = n->right)
4131 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
4134 for (i = TREE_INT_CST_LOW (n->low); i <= TREE_INT_CST_LOW (n->high); i++)
4135 if (cost_table[i] < 0)
4139 /* All interesting values are within the range of interesting
4140 ASCII characters. */
4144 /* Scan an ordered list of case nodes
4145 combining those with consecutive values or ranges.
4147 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
4150 group_case_nodes (head)
4153 case_node_ptr node = head;
4157 rtx lb = next_real_insn (label_rtx (node->code_label));
4158 case_node_ptr np = node;
4160 /* Try to group the successors of NODE with NODE. */
4161 while (((np = np->right) != 0)
4162 /* Do they jump to the same place? */
4163 && next_real_insn (label_rtx (np->code_label)) == lb
4164 /* Are their ranges consecutive? */
4165 && tree_int_cst_equal (np->low,
4166 fold (build (PLUS_EXPR,
4167 TREE_TYPE (node->high),
4170 /* An overflow is not consecutive. */
4171 && tree_int_cst_lt (node->high,
4172 fold (build (PLUS_EXPR,
4173 TREE_TYPE (node->high),
4175 integer_one_node))))
4177 node->high = np->high;
4179 /* NP is the first node after NODE which can't be grouped with it.
4180 Delete the nodes in between, and move on to that node. */
4186 /* Take an ordered list of case nodes
4187 and transform them into a near optimal binary tree,
4188 on the assumption that any target code selection value is as
4189 likely as any other.
4191 The transformation is performed by splitting the ordered
4192 list into two equal sections plus a pivot. The parts are
4193 then attached to the pivot as left and right branches. Each
4194 branch is is then transformed recursively. */
4197 balance_case_nodes (head, parent)
4198 case_node_ptr *head;
4199 case_node_ptr parent;
4201 register case_node_ptr np;
4209 register case_node_ptr *npp;
4212 /* Count the number of entries on branch. Also count the ranges. */
4216 if (!tree_int_cst_equal (np->low, np->high))
4220 cost += cost_table[TREE_INT_CST_LOW (np->high)];
4224 cost += cost_table[TREE_INT_CST_LOW (np->low)];
4232 /* Split this list if it is long enough for that to help. */
4237 /* Find the place in the list that bisects the list's total cost,
4238 Here I gets half the total cost. */
4243 /* Skip nodes while their cost does not reach that amount. */
4244 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
4245 i -= cost_table[TREE_INT_CST_LOW ((*npp)->high)];
4246 i -= cost_table[TREE_INT_CST_LOW ((*npp)->low)];
4249 npp = &(*npp)->right;
4254 /* Leave this branch lopsided, but optimize left-hand
4255 side and fill in `parent' fields for right-hand side. */
4257 np->parent = parent;
4258 balance_case_nodes (&np->left, np);
4259 for (; np->right; np = np->right)
4260 np->right->parent = np;
4264 /* If there are just three nodes, split at the middle one. */
4266 npp = &(*npp)->right;
4269 /* Find the place in the list that bisects the list's total cost,
4270 where ranges count as 2.
4271 Here I gets half the total cost. */
4272 i = (i + ranges + 1) / 2;
4275 /* Skip nodes while their cost does not reach that amount. */
4276 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
4281 npp = &(*npp)->right;
4286 np->parent = parent;
4289 /* Optimize each of the two split parts. */
4290 balance_case_nodes (&np->left, np);
4291 balance_case_nodes (&np->right, np);
4295 /* Else leave this branch as one level,
4296 but fill in `parent' fields. */
4298 np->parent = parent;
4299 for (; np->right; np = np->right)
4300 np->right->parent = np;
4305 /* Search the parent sections of the case node tree
4306 to see if a test for the lower bound of NODE would be redundant.
4307 INDEX_TYPE is the type of the index expression.
4309 The instructions to generate the case decision tree are
4310 output in the same order as nodes are processed so it is
4311 known that if a parent node checks the range of the current
4312 node minus one that the current node is bounded at its lower
4313 span. Thus the test would be redundant. */
4316 node_has_low_bound (node, index_type)
4321 case_node_ptr pnode;
4323 /* If the lower bound of this node is the lowest value in the index type,
4324 we need not test it. */
4326 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
4329 /* If this node has a left branch, the value at the left must be less
4330 than that at this node, so it cannot be bounded at the bottom and
4331 we need not bother testing any further. */
4336 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
4337 node->low, integer_one_node));
4339 /* If the subtraction above overflowed, we can't verify anything.
4340 Otherwise, look for a parent that tests our value - 1. */
4342 if (! tree_int_cst_lt (low_minus_one, node->low))
4345 for (pnode = node->parent; pnode; pnode = pnode->parent)
4346 if (tree_int_cst_equal (low_minus_one, pnode->high))
4352 /* Search the parent sections of the case node tree
4353 to see if a test for the upper bound of NODE would be redundant.
4354 INDEX_TYPE is the type of the index expression.
4356 The instructions to generate the case decision tree are
4357 output in the same order as nodes are processed so it is
4358 known that if a parent node checks the range of the current
4359 node plus one that the current node is bounded at its upper
4360 span. Thus the test would be redundant. */
4363 node_has_high_bound (node, index_type)
4368 case_node_ptr pnode;
4370 /* If the upper bound of this node is the highest value in the type
4371 of the index expression, we need not test against it. */
4373 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
4376 /* If this node has a right branch, the value at the right must be greater
4377 than that at this node, so it cannot be bounded at the top and
4378 we need not bother testing any further. */
4383 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
4384 node->high, integer_one_node));
4386 /* If the addition above overflowed, we can't verify anything.
4387 Otherwise, look for a parent that tests our value + 1. */
4389 if (! tree_int_cst_lt (node->high, high_plus_one))
4392 for (pnode = node->parent; pnode; pnode = pnode->parent)
4393 if (tree_int_cst_equal (high_plus_one, pnode->low))
4399 /* Search the parent sections of the
4400 case node tree to see if both tests for the upper and lower
4401 bounds of NODE would be redundant. */
4404 node_is_bounded (node, index_type)
4408 return (node_has_low_bound (node, index_type)
4409 && node_has_high_bound (node, index_type));
4412 /* Emit an unconditional jump to LABEL unless it would be dead code. */
4415 emit_jump_if_reachable (label)
4418 if (GET_CODE (get_last_insn ()) != BARRIER)
4422 /* Emit step-by-step code to select a case for the value of INDEX.
4423 The thus generated decision tree follows the form of the
4424 case-node binary tree NODE, whose nodes represent test conditions.
4425 INDEX_TYPE is the type of the index of the switch.
4427 Care is taken to prune redundant tests from the decision tree
4428 by detecting any boundary conditions already checked by
4429 emitted rtx. (See node_has_high_bound, node_has_low_bound
4430 and node_is_bounded, above.)
4432 Where the test conditions can be shown to be redundant we emit
4433 an unconditional jump to the target code. As a further
4434 optimization, the subordinates of a tree node are examined to
4435 check for bounded nodes. In this case conditional and/or
4436 unconditional jumps as a result of the boundary check for the
4437 current node are arranged to target the subordinates associated
4438 code for out of bound conditions on the current node node.
4440 We can assume that when control reaches the code generated here,
4441 the index value has already been compared with the parents
4442 of this node, and determined to be on the same side of each parent
4443 as this node is. Thus, if this node tests for the value 51,
4444 and a parent tested for 52, we don't need to consider
4445 the possibility of a value greater than 51. If another parent
4446 tests for the value 50, then this node need not test anything. */
4449 emit_case_nodes (index, node, default_label, index_type)
4455 /* If INDEX has an unsigned type, we must make unsigned branches. */
4456 int unsignedp = TREE_UNSIGNED (index_type);
4457 typedef rtx rtx_function ();
4458 rtx_function *gen_bgt_pat = unsignedp ? gen_bgtu : gen_bgt;
4459 rtx_function *gen_bge_pat = unsignedp ? gen_bgeu : gen_bge;
4460 rtx_function *gen_blt_pat = unsignedp ? gen_bltu : gen_blt;
4461 rtx_function *gen_ble_pat = unsignedp ? gen_bleu : gen_ble;
4462 enum machine_mode mode = GET_MODE (index);
4464 /* See if our parents have already tested everything for us.
4465 If they have, emit an unconditional jump for this node. */
4466 if (node_is_bounded (node, index_type))
4467 emit_jump (label_rtx (node->code_label));
4469 else if (tree_int_cst_equal (node->low, node->high))
4471 /* Node is single valued. First see if the index expression matches
4472 this node and then check our children, if any. */
4474 do_jump_if_equal (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
4475 label_rtx (node->code_label), unsignedp);
4477 if (node->right != 0 && node->left != 0)
4479 /* This node has children on both sides.
4480 Dispatch to one side or the other
4481 by comparing the index value with this node's value.
4482 If one subtree is bounded, check that one first,
4483 so we can avoid real branches in the tree. */
4485 if (node_is_bounded (node->right, index_type))
4487 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4489 GT, NULL_RTX, mode, unsignedp, 0);
4491 emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
4492 emit_case_nodes (index, node->left, default_label, index_type);
4495 else if (node_is_bounded (node->left, index_type))
4497 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4499 LT, NULL_RTX, mode, unsignedp, 0);
4500 emit_jump_insn ((*gen_blt_pat) (label_rtx (node->left->code_label)));
4501 emit_case_nodes (index, node->right, default_label, index_type);
4506 /* Neither node is bounded. First distinguish the two sides;
4507 then emit the code for one side at a time. */
4510 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
4512 /* See if the value is on the right. */
4513 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4515 GT, NULL_RTX, mode, unsignedp, 0);
4516 emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
4518 /* Value must be on the left.
4519 Handle the left-hand subtree. */
4520 emit_case_nodes (index, node->left, default_label, index_type);
4521 /* If left-hand subtree does nothing,
4523 emit_jump_if_reachable (default_label);
4525 /* Code branches here for the right-hand subtree. */
4526 expand_label (test_label);
4527 emit_case_nodes (index, node->right, default_label, index_type);
4531 else if (node->right != 0 && node->left == 0)
4533 /* Here we have a right child but no left so we issue conditional
4534 branch to default and process the right child.
4536 Omit the conditional branch to default if we it avoid only one
4537 right child; it costs too much space to save so little time. */
4539 if (node->right->right || node->right->left
4540 || !tree_int_cst_equal (node->right->low, node->right->high))
4542 if (!node_has_low_bound (node, index_type))
4544 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4546 LT, NULL_RTX, mode, unsignedp, 0);
4547 emit_jump_insn ((*gen_blt_pat) (default_label));
4550 emit_case_nodes (index, node->right, default_label, index_type);
4553 /* We cannot process node->right normally
4554 since we haven't ruled out the numbers less than
4555 this node's value. So handle node->right explicitly. */
4556 do_jump_if_equal (index,
4557 expand_expr (node->right->low, NULL_RTX,
4559 label_rtx (node->right->code_label), unsignedp);
4562 else if (node->right == 0 && node->left != 0)
4564 /* Just one subtree, on the left. */
4566 #if 0 /* The following code and comment were formerly part
4567 of the condition here, but they didn't work
4568 and I don't understand what the idea was. -- rms. */
4569 /* If our "most probable entry" is less probable
4570 than the default label, emit a jump to
4571 the default label using condition codes
4572 already lying around. With no right branch,
4573 a branch-greater-than will get us to the default
4576 && cost_table[TREE_INT_CST_LOW (node->high)] < 12)
4579 if (node->left->left || node->left->right
4580 || !tree_int_cst_equal (node->left->low, node->left->high))
4582 if (!node_has_high_bound (node, index_type))
4584 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4586 GT, NULL_RTX, mode, unsignedp, 0);
4587 emit_jump_insn ((*gen_bgt_pat) (default_label));
4590 emit_case_nodes (index, node->left, default_label, index_type);
4593 /* We cannot process node->left normally
4594 since we haven't ruled out the numbers less than
4595 this node's value. So handle node->left explicitly. */
4596 do_jump_if_equal (index,
4597 expand_expr (node->left->low, NULL_RTX,
4599 label_rtx (node->left->code_label), unsignedp);
4604 /* Node is a range. These cases are very similar to those for a single
4605 value, except that we do not start by testing whether this node
4606 is the one to branch to. */
4608 if (node->right != 0 && node->left != 0)
4610 /* Node has subtrees on both sides.
4611 If the right-hand subtree is bounded,
4612 test for it first, since we can go straight there.
4613 Otherwise, we need to make a branch in the control structure,
4614 then handle the two subtrees. */
4615 tree test_label = 0;
4617 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4619 GT, NULL_RTX, mode, unsignedp, 0);
4621 if (node_is_bounded (node->right, index_type))
4622 /* Right hand node is fully bounded so we can eliminate any
4623 testing and branch directly to the target code. */
4624 emit_jump_insn ((*gen_bgt_pat) (label_rtx (node->right->code_label)));
4627 /* Right hand node requires testing.
4628 Branch to a label where we will handle it later. */
4630 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
4631 emit_jump_insn ((*gen_bgt_pat) (label_rtx (test_label)));
4634 /* Value belongs to this node or to the left-hand subtree. */
4636 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
4637 GE, NULL_RTX, mode, unsignedp, 0);
4638 emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
4640 /* Handle the left-hand subtree. */
4641 emit_case_nodes (index, node->left, default_label, index_type);
4643 /* If right node had to be handled later, do that now. */
4647 /* If the left-hand subtree fell through,
4648 don't let it fall into the right-hand subtree. */
4649 emit_jump_if_reachable (default_label);
4651 expand_label (test_label);
4652 emit_case_nodes (index, node->right, default_label, index_type);
4656 else if (node->right != 0 && node->left == 0)
4658 /* Deal with values to the left of this node,
4659 if they are possible. */
4660 if (!node_has_low_bound (node, index_type))
4662 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
4664 LT, NULL_RTX, mode, unsignedp, 0);
4665 emit_jump_insn ((*gen_blt_pat) (default_label));
4668 /* Value belongs to this node or to the right-hand subtree. */
4670 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4672 LE, NULL_RTX, mode, unsignedp, 0);
4673 emit_jump_insn ((*gen_ble_pat) (label_rtx (node->code_label)));
4675 emit_case_nodes (index, node->right, default_label, index_type);
4678 else if (node->right == 0 && node->left != 0)
4680 /* Deal with values to the right of this node,
4681 if they are possible. */
4682 if (!node_has_high_bound (node, index_type))
4684 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4686 GT, NULL_RTX, mode, unsignedp, 0);
4687 emit_jump_insn ((*gen_bgt_pat) (default_label));
4690 /* Value belongs to this node or to the left-hand subtree. */
4692 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
4693 GE, NULL_RTX, mode, unsignedp, 0);
4694 emit_jump_insn ((*gen_bge_pat) (label_rtx (node->code_label)));
4696 emit_case_nodes (index, node->left, default_label, index_type);
4701 /* Node has no children so we check low and high bounds to remove
4702 redundant tests. Only one of the bounds can exist,
4703 since otherwise this node is bounded--a case tested already. */
4705 if (!node_has_high_bound (node, index_type))
4707 emit_cmp_insn (index, expand_expr (node->high, NULL_RTX,
4709 GT, NULL_RTX, mode, unsignedp, 0);
4710 emit_jump_insn ((*gen_bgt_pat) (default_label));
4713 if (!node_has_low_bound (node, index_type))
4715 emit_cmp_insn (index, expand_expr (node->low, NULL_RTX,
4717 LT, NULL_RTX, mode, unsignedp, 0);
4718 emit_jump_insn ((*gen_blt_pat) (default_label));
4721 emit_jump (label_rtx (node->code_label));
4726 /* These routines are used by the loop unrolling code. They copy BLOCK trees
4727 so that the debugging info will be correct for the unrolled loop. */
4729 /* Indexed by block number, contains a pointer to the N'th block node. */
4731 static tree *block_vector;
4734 find_loop_tree_blocks ()
4736 tree block = DECL_INITIAL (current_function_decl);
4738 /* There first block is for the function body, and does not have
4739 corresponding block notes. Don't include it in the block vector. */
4740 block = BLOCK_SUBBLOCKS (block);
4742 block_vector = identify_blocks (block, get_insns ());
4746 unroll_block_trees ()
4748 tree block = DECL_INITIAL (current_function_decl);
4750 reorder_blocks (block_vector, block, get_insns ());