1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 1988, 1989, 1992, 1993, 1994, 1995, 1996, 1997,
3 1998, 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
23 /* This file handles the generation of rtl code from tree structure
24 above the level of expressions, using subroutines in exp*.c and emit-rtl.c.
25 It also creates the rtl expressions for parameters and auto variables
26 and has full responsibility for allocating stack slots.
28 The functions whose names start with `expand_' are called by the
29 parser to generate RTL instructions for various kinds of constructs.
31 Some control and binding constructs require calling several such
32 functions at different times. For example, a simple if-then
33 is expanded by calling `expand_start_cond' (with the condition-expression
34 as argument) before parsing the then-clause and calling `expand_end_cond'
35 after parsing the then-clause. */
46 #include "insn-flags.h"
47 #include "insn-config.h"
48 #include "insn-codes.h"
50 #include "hard-reg-set.h"
59 #define obstack_chunk_alloc xmalloc
60 #define obstack_chunk_free free
61 struct obstack stmt_obstack;
63 /* Assume that case vectors are not pc-relative. */
64 #ifndef CASE_VECTOR_PC_RELATIVE
65 #define CASE_VECTOR_PC_RELATIVE 0
69 /* Functions and data structures for expanding case statements. */
71 /* Case label structure, used to hold info on labels within case
72 statements. We handle "range" labels; for a single-value label
73 as in C, the high and low limits are the same.
75 An AVL tree of case nodes is initially created, and later transformed
76 to a list linked via the RIGHT fields in the nodes. Nodes with
77 higher case values are later in the list.
79 Switch statements can be output in one of two forms. A branch table
80 is used if there are more than a few labels and the labels are dense
81 within the range between the smallest and largest case value. If a
82 branch table is used, no further manipulations are done with the case
85 The alternative to the use of a branch table is to generate a series
86 of compare and jump insns. When that is done, we use the LEFT, RIGHT,
87 and PARENT fields to hold a binary tree. Initially the tree is
88 totally unbalanced, with everything on the right. We balance the tree
89 with nodes on the left having lower case values than the parent
90 and nodes on the right having higher values. We then output the tree
95 struct case_node *left; /* Left son in binary tree */
96 struct case_node *right; /* Right son in binary tree; also node chain */
97 struct case_node *parent; /* Parent of node in binary tree */
98 tree low; /* Lowest index value for this label */
99 tree high; /* Highest index value for this label */
100 tree code_label; /* Label to jump to when node matches */
104 typedef struct case_node case_node;
105 typedef struct case_node *case_node_ptr;
107 /* These are used by estimate_case_costs and balance_case_nodes. */
109 /* This must be a signed type, and non-ANSI compilers lack signed char. */
110 static short cost_table_[129];
111 static short *cost_table;
112 static int use_cost_table;
114 /* Stack of control and binding constructs we are currently inside.
116 These constructs begin when you call `expand_start_WHATEVER'
117 and end when you call `expand_end_WHATEVER'. This stack records
118 info about how the construct began that tells the end-function
119 what to do. It also may provide information about the construct
120 to alter the behavior of other constructs within the body.
121 For example, they may affect the behavior of C `break' and `continue'.
123 Each construct gets one `struct nesting' object.
124 All of these objects are chained through the `all' field.
125 `nesting_stack' points to the first object (innermost construct).
126 The position of an entry on `nesting_stack' is in its `depth' field.
128 Each type of construct has its own individual stack.
129 For example, loops have `loop_stack'. Each object points to the
130 next object of the same type through the `next' field.
132 Some constructs are visible to `break' exit-statements and others
133 are not. Which constructs are visible depends on the language.
134 Therefore, the data structure allows each construct to be visible
135 or not, according to the args given when the construct is started.
136 The construct is visible if the `exit_label' field is non-null.
137 In that case, the value should be a CODE_LABEL rtx. */
142 struct nesting *next;
147 /* For conds (if-then and if-then-else statements). */
150 /* Label for the end of the if construct.
151 There is none if EXITFLAG was not set
152 and no `else' has been seen yet. */
154 /* Label for the end of this alternative.
155 This may be the end of the if or the next else/elseif. */
161 /* Label at the top of the loop; place to loop back to. */
163 /* Label at the end of the whole construct. */
165 /* Label before a jump that branches to the end of the whole
166 construct. This is where destructors go if any. */
168 /* Label for `continue' statement to jump to;
169 this is in front of the stepper of the loop. */
172 /* For variable binding contours. */
175 /* Sequence number of this binding contour within the function,
176 in order of entry. */
177 int block_start_count;
178 /* Nonzero => value to restore stack to on exit. */
180 /* The NOTE that starts this contour.
181 Used by expand_goto to check whether the destination
182 is within each contour or not. */
184 /* Innermost containing binding contour that has a stack level. */
185 struct nesting *innermost_stack_block;
186 /* List of cleanups to be run on exit from this contour.
187 This is a list of expressions to be evaluated.
188 The TREE_PURPOSE of each link is the ..._DECL node
189 which the cleanup pertains to. */
191 /* List of cleanup-lists of blocks containing this block,
192 as they were at the locus where this block appears.
193 There is an element for each containing block,
194 ordered innermost containing block first.
195 The tail of this list can be 0,
196 if all remaining elements would be empty lists.
197 The element's TREE_VALUE is the cleanup-list of that block,
198 which may be null. */
200 /* Chain of labels defined inside this binding contour.
201 For contours that have stack levels or cleanups. */
202 struct label_chain *label_chain;
203 /* Number of function calls seen, as of start of this block. */
204 int n_function_calls;
205 /* Nonzero if this is associated with a EH region. */
206 int exception_region;
207 /* The saved target_temp_slot_level from our outer block.
208 We may reset target_temp_slot_level to be the level of
209 this block, if that is done, target_temp_slot_level
210 reverts to the saved target_temp_slot_level at the very
212 int block_target_temp_slot_level;
213 /* True if we are currently emitting insns in an area of
214 output code that is controlled by a conditional
215 expression. This is used by the cleanup handling code to
216 generate conditional cleanup actions. */
217 int conditional_code;
218 /* A place to move the start of the exception region for any
219 of the conditional cleanups, must be at the end or after
220 the start of the last unconditional cleanup, and before any
221 conditional branch points. */
222 rtx last_unconditional_cleanup;
223 /* When in a conditional context, this is the specific
224 cleanup list associated with last_unconditional_cleanup,
225 where we place the conditionalized cleanups. */
228 /* For switch (C) or case (Pascal) statements,
229 and also for dummies (see `expand_start_case_dummy'). */
232 /* The insn after which the case dispatch should finally
233 be emitted. Zero for a dummy. */
235 /* A list of case labels; it is first built as an AVL tree.
236 During expand_end_case, this is converted to a list, and may be
237 rearranged into a nearly balanced binary tree. */
238 struct case_node *case_list;
239 /* Label to jump to if no case matches. */
241 /* The expression to be dispatched on. */
243 /* Type that INDEX_EXPR should be converted to. */
245 /* Number of range exprs in case statement. */
247 /* Name of this kind of statement, for warnings. */
248 const char *printname;
249 /* Used to save no_line_numbers till we see the first case label.
250 We set this to -1 when we see the first case label in this
252 int line_number_status;
257 /* Allocate and return a new `struct nesting'. */
259 #define ALLOC_NESTING() \
260 (struct nesting *) obstack_alloc (&stmt_obstack, sizeof (struct nesting))
262 /* Pop the nesting stack element by element until we pop off
263 the element which is at the top of STACK.
264 Update all the other stacks, popping off elements from them
265 as we pop them from nesting_stack. */
267 #define POPSTACK(STACK) \
268 do { struct nesting *target = STACK; \
269 struct nesting *this; \
270 do { this = nesting_stack; \
271 if (loop_stack == this) \
272 loop_stack = loop_stack->next; \
273 if (cond_stack == this) \
274 cond_stack = cond_stack->next; \
275 if (block_stack == this) \
276 block_stack = block_stack->next; \
277 if (stack_block_stack == this) \
278 stack_block_stack = stack_block_stack->next; \
279 if (case_stack == this) \
280 case_stack = case_stack->next; \
281 nesting_depth = nesting_stack->depth - 1; \
282 nesting_stack = this->all; \
283 obstack_free (&stmt_obstack, this); } \
284 while (this != target); } while (0)
286 /* In some cases it is impossible to generate code for a forward goto
287 until the label definition is seen. This happens when it may be necessary
288 for the goto to reset the stack pointer: we don't yet know how to do that.
289 So expand_goto puts an entry on this fixup list.
290 Each time a binding contour that resets the stack is exited,
292 If the target label has now been defined, we can insert the proper code. */
296 /* Points to following fixup. */
297 struct goto_fixup *next;
298 /* Points to the insn before the jump insn.
299 If more code must be inserted, it goes after this insn. */
301 /* The LABEL_DECL that this jump is jumping to, or 0
302 for break, continue or return. */
304 /* The BLOCK for the place where this goto was found. */
306 /* The CODE_LABEL rtx that this is jumping to. */
308 /* Number of binding contours started in current function
309 before the label reference. */
310 int block_start_count;
311 /* The outermost stack level that should be restored for this jump.
312 Each time a binding contour that resets the stack is exited,
313 if the target label is *not* yet defined, this slot is updated. */
315 /* List of lists of cleanup expressions to be run by this goto.
316 There is one element for each block that this goto is within.
317 The tail of this list can be 0,
318 if all remaining elements would be empty.
319 The TREE_VALUE contains the cleanup list of that block as of the
320 time this goto was seen.
321 The TREE_ADDRESSABLE flag is 1 for a block that has been exited. */
322 tree cleanup_list_list;
325 /* Within any binding contour that must restore a stack level,
326 all labels are recorded with a chain of these structures. */
330 /* Points to following fixup. */
331 struct label_chain *next;
337 /* Chain of all pending binding contours. */
338 struct nesting *x_block_stack;
340 /* If any new stacks are added here, add them to POPSTACKS too. */
342 /* Chain of all pending binding contours that restore stack levels
344 struct nesting *x_stack_block_stack;
346 /* Chain of all pending conditional statements. */
347 struct nesting *x_cond_stack;
349 /* Chain of all pending loops. */
350 struct nesting *x_loop_stack;
352 /* Chain of all pending case or switch statements. */
353 struct nesting *x_case_stack;
355 /* Separate chain including all of the above,
356 chained through the `all' field. */
357 struct nesting *x_nesting_stack;
359 /* Number of entries on nesting_stack now. */
362 /* Number of binding contours started so far in this function. */
363 int x_block_start_count;
365 /* Each time we expand an expression-statement,
366 record the expr's type and its RTL value here. */
367 tree x_last_expr_type;
368 rtx x_last_expr_value;
370 /* Nonzero if within a ({...}) grouping, in which case we must
371 always compute a value for each expr-stmt in case it is the last one. */
372 int x_expr_stmts_for_value;
374 /* Filename and line number of last line-number note,
375 whether we actually emitted it or not. */
376 const char *x_emit_filename;
379 struct goto_fixup *x_goto_fixup_chain;
382 #define block_stack (cfun->stmt->x_block_stack)
383 #define stack_block_stack (cfun->stmt->x_stack_block_stack)
384 #define cond_stack (cfun->stmt->x_cond_stack)
385 #define loop_stack (cfun->stmt->x_loop_stack)
386 #define case_stack (cfun->stmt->x_case_stack)
387 #define nesting_stack (cfun->stmt->x_nesting_stack)
388 #define nesting_depth (cfun->stmt->x_nesting_depth)
389 #define current_block_start_count (cfun->stmt->x_block_start_count)
390 #define last_expr_type (cfun->stmt->x_last_expr_type)
391 #define last_expr_value (cfun->stmt->x_last_expr_value)
392 #define expr_stmts_for_value (cfun->stmt->x_expr_stmts_for_value)
393 #define emit_filename (cfun->stmt->x_emit_filename)
394 #define emit_lineno (cfun->stmt->x_emit_lineno)
395 #define goto_fixup_chain (cfun->stmt->x_goto_fixup_chain)
397 /* Non-zero if we are using EH to handle cleanus. */
398 static int using_eh_for_cleanups_p = 0;
400 /* Character strings, each containing a single decimal digit. */
401 static char *digit_strings[10];
404 static int n_occurrences PARAMS ((int, const char *));
405 static void expand_goto_internal PARAMS ((tree, rtx, rtx));
406 static int expand_fixup PARAMS ((tree, rtx, rtx));
407 static rtx expand_nl_handler_label PARAMS ((rtx, rtx));
408 static void expand_nl_goto_receiver PARAMS ((void));
409 static void expand_nl_goto_receivers PARAMS ((struct nesting *));
410 static void fixup_gotos PARAMS ((struct nesting *, rtx, tree,
412 static void expand_null_return_1 PARAMS ((rtx, int));
413 static void expand_value_return PARAMS ((rtx));
414 static int tail_recursion_args PARAMS ((tree, tree));
415 static void expand_cleanups PARAMS ((tree, tree, int, int));
416 static void check_seenlabel PARAMS ((void));
417 static void do_jump_if_equal PARAMS ((rtx, rtx, rtx, int));
418 static int estimate_case_costs PARAMS ((case_node_ptr));
419 static void group_case_nodes PARAMS ((case_node_ptr));
420 static void balance_case_nodes PARAMS ((case_node_ptr *,
422 static int node_has_low_bound PARAMS ((case_node_ptr, tree));
423 static int node_has_high_bound PARAMS ((case_node_ptr, tree));
424 static int node_is_bounded PARAMS ((case_node_ptr, tree));
425 static void emit_jump_if_reachable PARAMS ((rtx));
426 static void emit_case_nodes PARAMS ((rtx, case_node_ptr, rtx, tree));
427 static int add_case_node PARAMS ((tree, tree, tree, tree *));
428 static struct case_node *case_tree2list PARAMS ((case_node *, case_node *));
429 static void mark_cond_nesting PARAMS ((struct nesting *));
430 static void mark_loop_nesting PARAMS ((struct nesting *));
431 static void mark_block_nesting PARAMS ((struct nesting *));
432 static void mark_case_nesting PARAMS ((struct nesting *));
433 static void mark_goto_fixup PARAMS ((struct goto_fixup *));
437 using_eh_for_cleanups ()
439 using_eh_for_cleanups_p = 1;
442 /* Mark N (known to be a cond-nesting) for GC. */
445 mark_cond_nesting (n)
450 ggc_mark_rtx (n->exit_label);
451 ggc_mark_rtx (n->data.cond.endif_label);
452 ggc_mark_rtx (n->data.cond.next_label);
458 /* Mark N (known to be a loop-nesting) for GC. */
461 mark_loop_nesting (n)
467 ggc_mark_rtx (n->exit_label);
468 ggc_mark_rtx (n->data.loop.start_label);
469 ggc_mark_rtx (n->data.loop.end_label);
470 ggc_mark_rtx (n->data.loop.alt_end_label);
471 ggc_mark_rtx (n->data.loop.continue_label);
477 /* Mark N (known to be a block-nesting) for GC. */
480 mark_block_nesting (n)
485 struct label_chain *l;
487 ggc_mark_rtx (n->exit_label);
488 ggc_mark_rtx (n->data.block.stack_level);
489 ggc_mark_rtx (n->data.block.first_insn);
490 ggc_mark_tree (n->data.block.cleanups);
491 ggc_mark_tree (n->data.block.outer_cleanups);
493 for (l = n->data.block.label_chain; l != NULL; l = l->next)
494 ggc_mark_tree (l->label);
496 ggc_mark_rtx (n->data.block.last_unconditional_cleanup);
498 /* ??? cleanup_ptr never points outside the stack, does it? */
504 /* Mark N (known to be a case-nesting) for GC. */
507 mark_case_nesting (n)
512 struct case_node *node;
514 ggc_mark_rtx (n->exit_label);
515 ggc_mark_rtx (n->data.case_stmt.start);
517 node = n->data.case_stmt.case_list;
520 ggc_mark_tree (node->low);
521 ggc_mark_tree (node->high);
522 ggc_mark_tree (node->code_label);
526 ggc_mark_tree (n->data.case_stmt.default_label);
527 ggc_mark_tree (n->data.case_stmt.index_expr);
528 ggc_mark_tree (n->data.case_stmt.nominal_type);
538 struct goto_fixup *g;
542 ggc_mark_rtx (g->before_jump);
543 ggc_mark_tree (g->target);
544 ggc_mark_tree (g->context);
545 ggc_mark_rtx (g->target_rtl);
546 ggc_mark_rtx (g->stack_level);
547 ggc_mark_tree (g->cleanup_list_list);
553 /* Clear out all parts of the state in F that can safely be discarded
554 after the function has been compiled, to let garbage collection
555 reclaim the memory. */
561 /* We're about to free the function obstack. If we hold pointers to
562 things allocated there, then we'll try to mark them when we do
563 GC. So, we clear them out here explicitly. */
573 struct stmt_status *p;
578 mark_block_nesting (p->x_block_stack);
579 mark_cond_nesting (p->x_cond_stack);
580 mark_loop_nesting (p->x_loop_stack);
581 mark_case_nesting (p->x_case_stack);
583 ggc_mark_tree (p->x_last_expr_type);
584 /* last_epxr_value is only valid if last_expr_type is nonzero. */
585 if (p->x_last_expr_type)
586 ggc_mark_rtx (p->x_last_expr_value);
588 mark_goto_fixup (p->x_goto_fixup_chain);
596 gcc_obstack_init (&stmt_obstack);
598 for (i = 0; i < 10; i++)
600 digit_strings[i] = ggc_alloc_string (NULL, 1);
601 digit_strings[i][0] = '0' + i;
603 ggc_add_string_root (digit_strings, 10);
607 init_stmt_for_function ()
609 cfun->stmt = (struct stmt_status *) xmalloc (sizeof (struct stmt_status));
611 /* We are not currently within any block, conditional, loop or case. */
613 stack_block_stack = 0;
620 current_block_start_count = 0;
622 /* No gotos have been expanded yet. */
623 goto_fixup_chain = 0;
625 /* We are not processing a ({...}) grouping. */
626 expr_stmts_for_value = 0;
628 last_expr_value = NULL_RTX;
631 /* Return nonzero if anything is pushed on the loop, condition, or case
636 return cond_stack || loop_stack || case_stack;
639 /* Record the current file and line. Called from emit_line_note. */
641 set_file_and_line_for_stmt (file, line)
645 /* If we're outputting an inline function, and we add a line note,
646 there may be no CFUN->STMT information. So, there's no need to
650 emit_filename = file;
655 /* Emit a no-op instruction. */
662 last_insn = get_last_insn ();
664 && (GET_CODE (last_insn) == CODE_LABEL
665 || (GET_CODE (last_insn) == NOTE
666 && prev_real_insn (last_insn) == 0)))
667 emit_insn (gen_nop ());
670 /* Return the rtx-label that corresponds to a LABEL_DECL,
671 creating it if necessary. */
677 if (TREE_CODE (label) != LABEL_DECL)
680 if (DECL_RTL (label))
681 return DECL_RTL (label);
683 return DECL_RTL (label) = gen_label_rtx ();
686 /* Add an unconditional jump to LABEL as the next sequential instruction. */
692 do_pending_stack_adjust ();
693 emit_jump_insn (gen_jump (label));
697 /* Emit code to jump to the address
698 specified by the pointer expression EXP. */
701 expand_computed_goto (exp)
704 rtx x = expand_expr (exp, NULL_RTX, VOIDmode, 0);
706 #ifdef POINTERS_EXTEND_UNSIGNED
707 x = convert_memory_address (Pmode, x);
711 /* Be sure the function is executable. */
712 if (current_function_check_memory_usage)
713 emit_library_call (chkr_check_exec_libfunc, 1,
714 VOIDmode, 1, x, ptr_mode);
716 do_pending_stack_adjust ();
717 emit_indirect_jump (x);
719 current_function_has_computed_jump = 1;
722 /* Handle goto statements and the labels that they can go to. */
724 /* Specify the location in the RTL code of a label LABEL,
725 which is a LABEL_DECL tree node.
727 This is used for the kind of label that the user can jump to with a
728 goto statement, and for alternatives of a switch or case statement.
729 RTL labels generated for loops and conditionals don't go through here;
730 they are generated directly at the RTL level, by other functions below.
732 Note that this has nothing to do with defining label *names*.
733 Languages vary in how they do that and what that even means. */
739 struct label_chain *p;
741 do_pending_stack_adjust ();
742 emit_label (label_rtx (label));
743 if (DECL_NAME (label))
744 LABEL_NAME (DECL_RTL (label)) = IDENTIFIER_POINTER (DECL_NAME (label));
746 if (stack_block_stack != 0)
748 p = (struct label_chain *) oballoc (sizeof (struct label_chain));
749 p->next = stack_block_stack->data.block.label_chain;
750 stack_block_stack->data.block.label_chain = p;
755 /* Declare that LABEL (a LABEL_DECL) may be used for nonlocal gotos
756 from nested functions. */
759 declare_nonlocal_label (label)
762 rtx slot = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
764 nonlocal_labels = tree_cons (NULL_TREE, label, nonlocal_labels);
765 LABEL_PRESERVE_P (label_rtx (label)) = 1;
766 if (nonlocal_goto_handler_slots == 0)
768 emit_stack_save (SAVE_NONLOCAL,
769 &nonlocal_goto_stack_level,
770 PREV_INSN (tail_recursion_reentry));
772 nonlocal_goto_handler_slots
773 = gen_rtx_EXPR_LIST (VOIDmode, slot, nonlocal_goto_handler_slots);
776 /* Generate RTL code for a `goto' statement with target label LABEL.
777 LABEL should be a LABEL_DECL tree node that was or will later be
778 defined with `expand_label'. */
786 /* Check for a nonlocal goto to a containing function. */
787 context = decl_function_context (label);
788 if (context != 0 && context != current_function_decl)
790 struct function *p = find_function_data (context);
791 rtx label_ref = gen_rtx_LABEL_REF (Pmode, label_rtx (label));
792 rtx temp, handler_slot;
795 /* Find the corresponding handler slot for this label. */
796 handler_slot = p->x_nonlocal_goto_handler_slots;
797 for (link = p->x_nonlocal_labels; TREE_VALUE (link) != label;
798 link = TREE_CHAIN (link))
799 handler_slot = XEXP (handler_slot, 1);
800 handler_slot = XEXP (handler_slot, 0);
802 p->has_nonlocal_label = 1;
803 current_function_has_nonlocal_goto = 1;
804 LABEL_REF_NONLOCAL_P (label_ref) = 1;
806 /* Copy the rtl for the slots so that they won't be shared in
807 case the virtual stack vars register gets instantiated differently
808 in the parent than in the child. */
810 #if HAVE_nonlocal_goto
811 if (HAVE_nonlocal_goto)
812 emit_insn (gen_nonlocal_goto (lookup_static_chain (label),
813 copy_rtx (handler_slot),
814 copy_rtx (p->x_nonlocal_goto_stack_level),
821 /* Restore frame pointer for containing function.
822 This sets the actual hard register used for the frame pointer
823 to the location of the function's incoming static chain info.
824 The non-local goto handler will then adjust it to contain the
825 proper value and reload the argument pointer, if needed. */
826 emit_move_insn (hard_frame_pointer_rtx, lookup_static_chain (label));
828 /* We have now loaded the frame pointer hardware register with
829 the address of that corresponds to the start of the virtual
830 stack vars. So replace virtual_stack_vars_rtx in all
831 addresses we use with stack_pointer_rtx. */
833 /* Get addr of containing function's current nonlocal goto handler,
834 which will do any cleanups and then jump to the label. */
835 addr = copy_rtx (handler_slot);
836 temp = copy_to_reg (replace_rtx (addr, virtual_stack_vars_rtx,
837 hard_frame_pointer_rtx));
839 /* Restore the stack pointer. Note this uses fp just restored. */
840 addr = p->x_nonlocal_goto_stack_level;
842 addr = replace_rtx (copy_rtx (addr),
843 virtual_stack_vars_rtx,
844 hard_frame_pointer_rtx);
846 emit_stack_restore (SAVE_NONLOCAL, addr, NULL_RTX);
848 /* USE of hard_frame_pointer_rtx added for consistency; not clear if
850 emit_insn (gen_rtx_USE (VOIDmode, hard_frame_pointer_rtx));
851 emit_insn (gen_rtx_USE (VOIDmode, stack_pointer_rtx));
852 emit_indirect_jump (temp);
856 expand_goto_internal (label, label_rtx (label), NULL_RTX);
859 /* Generate RTL code for a `goto' statement with target label BODY.
860 LABEL should be a LABEL_REF.
861 LAST_INSN, if non-0, is the rtx we should consider as the last
862 insn emitted (for the purposes of cleaning up a return). */
865 expand_goto_internal (body, label, last_insn)
870 struct nesting *block;
873 if (GET_CODE (label) != CODE_LABEL)
876 /* If label has already been defined, we can tell now
877 whether and how we must alter the stack level. */
879 if (PREV_INSN (label) != 0)
881 /* Find the innermost pending block that contains the label.
882 (Check containment by comparing insn-uids.)
883 Then restore the outermost stack level within that block,
884 and do cleanups of all blocks contained in it. */
885 for (block = block_stack; block; block = block->next)
887 if (INSN_UID (block->data.block.first_insn) < INSN_UID (label))
889 if (block->data.block.stack_level != 0)
890 stack_level = block->data.block.stack_level;
891 /* Execute the cleanups for blocks we are exiting. */
892 if (block->data.block.cleanups != 0)
894 expand_cleanups (block->data.block.cleanups, NULL_TREE, 1, 1);
895 do_pending_stack_adjust ();
901 /* Ensure stack adjust isn't done by emit_jump, as this
902 would clobber the stack pointer. This one should be
903 deleted as dead by flow. */
904 clear_pending_stack_adjust ();
905 do_pending_stack_adjust ();
906 emit_stack_restore (SAVE_BLOCK, stack_level, NULL_RTX);
909 if (body != 0 && DECL_TOO_LATE (body))
910 error ("jump to `%s' invalidly jumps into binding contour",
911 IDENTIFIER_POINTER (DECL_NAME (body)));
913 /* Label not yet defined: may need to put this goto
914 on the fixup list. */
915 else if (! expand_fixup (body, label, last_insn))
917 /* No fixup needed. Record that the label is the target
918 of at least one goto that has no fixup. */
920 TREE_ADDRESSABLE (body) = 1;
926 /* Generate if necessary a fixup for a goto
927 whose target label in tree structure (if any) is TREE_LABEL
928 and whose target in rtl is RTL_LABEL.
930 If LAST_INSN is nonzero, we pretend that the jump appears
931 after insn LAST_INSN instead of at the current point in the insn stream.
933 The fixup will be used later to insert insns just before the goto.
934 Those insns will restore the stack level as appropriate for the
935 target label, and will (in the case of C++) also invoke any object
936 destructors which have to be invoked when we exit the scopes which
937 are exited by the goto.
939 Value is nonzero if a fixup is made. */
942 expand_fixup (tree_label, rtl_label, last_insn)
947 struct nesting *block, *end_block;
949 /* See if we can recognize which block the label will be output in.
950 This is possible in some very common cases.
951 If we succeed, set END_BLOCK to that block.
952 Otherwise, set it to 0. */
955 && (rtl_label == cond_stack->data.cond.endif_label
956 || rtl_label == cond_stack->data.cond.next_label))
957 end_block = cond_stack;
958 /* If we are in a loop, recognize certain labels which
959 are likely targets. This reduces the number of fixups
960 we need to create. */
962 && (rtl_label == loop_stack->data.loop.start_label
963 || rtl_label == loop_stack->data.loop.end_label
964 || rtl_label == loop_stack->data.loop.continue_label))
965 end_block = loop_stack;
969 /* Now set END_BLOCK to the binding level to which we will return. */
973 struct nesting *next_block = end_block->all;
976 /* First see if the END_BLOCK is inside the innermost binding level.
977 If so, then no cleanups or stack levels are relevant. */
978 while (next_block && next_block != block)
979 next_block = next_block->all;
984 /* Otherwise, set END_BLOCK to the innermost binding level
985 which is outside the relevant control-structure nesting. */
986 next_block = block_stack->next;
987 for (block = block_stack; block != end_block; block = block->all)
988 if (block == next_block)
989 next_block = next_block->next;
990 end_block = next_block;
993 /* Does any containing block have a stack level or cleanups?
994 If not, no fixup is needed, and that is the normal case
995 (the only case, for standard C). */
996 for (block = block_stack; block != end_block; block = block->next)
997 if (block->data.block.stack_level != 0
998 || block->data.block.cleanups != 0)
1001 if (block != end_block)
1003 /* Ok, a fixup is needed. Add a fixup to the list of such. */
1004 struct goto_fixup *fixup
1005 = (struct goto_fixup *) oballoc (sizeof (struct goto_fixup));
1006 /* In case an old stack level is restored, make sure that comes
1007 after any pending stack adjust. */
1008 /* ?? If the fixup isn't to come at the present position,
1009 doing the stack adjust here isn't useful. Doing it with our
1010 settings at that location isn't useful either. Let's hope
1013 do_pending_stack_adjust ();
1014 fixup->target = tree_label;
1015 fixup->target_rtl = rtl_label;
1017 /* Create a BLOCK node and a corresponding matched set of
1018 NOTE_INSN_BLOCK_BEG and NOTE_INSN_BLOCK_END notes at
1019 this point. The notes will encapsulate any and all fixup
1020 code which we might later insert at this point in the insn
1021 stream. Also, the BLOCK node will be the parent (i.e. the
1022 `SUPERBLOCK') of any other BLOCK nodes which we might create
1023 later on when we are expanding the fixup code.
1025 Note that optimization passes (including expand_end_loop)
1026 might move the *_BLOCK notes away, so we use a NOTE_INSN_DELETED
1027 as a placeholder. */
1030 register rtx original_before_jump
1031 = last_insn ? last_insn : get_last_insn ();
1036 block = make_node (BLOCK);
1037 TREE_USED (block) = 1;
1039 if (!cfun->x_whole_function_mode_p)
1040 insert_block (block);
1044 = BLOCK_CHAIN (DECL_INITIAL (current_function_decl));
1045 BLOCK_CHAIN (DECL_INITIAL (current_function_decl))
1050 start = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
1051 if (cfun->x_whole_function_mode_p)
1052 NOTE_BLOCK (start) = block;
1053 fixup->before_jump = emit_note (NULL_PTR, NOTE_INSN_DELETED);
1054 end = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
1055 if (cfun->x_whole_function_mode_p)
1056 NOTE_BLOCK (end) = block;
1057 fixup->context = block;
1059 emit_insns_after (start, original_before_jump);
1062 fixup->block_start_count = current_block_start_count;
1063 fixup->stack_level = 0;
1064 fixup->cleanup_list_list
1065 = ((block->data.block.outer_cleanups
1066 || block->data.block.cleanups)
1067 ? tree_cons (NULL_TREE, block->data.block.cleanups,
1068 block->data.block.outer_cleanups)
1070 fixup->next = goto_fixup_chain;
1071 goto_fixup_chain = fixup;
1079 /* Expand any needed fixups in the outputmost binding level of the
1080 function. FIRST_INSN is the first insn in the function. */
1083 expand_fixups (first_insn)
1086 fixup_gotos (NULL_PTR, NULL_RTX, NULL_TREE, first_insn, 0);
1089 /* When exiting a binding contour, process all pending gotos requiring fixups.
1090 THISBLOCK is the structure that describes the block being exited.
1091 STACK_LEVEL is the rtx for the stack level to restore exiting this contour.
1092 CLEANUP_LIST is a list of expressions to evaluate on exiting this contour.
1093 FIRST_INSN is the insn that began this contour.
1095 Gotos that jump out of this contour must restore the
1096 stack level and do the cleanups before actually jumping.
1098 DONT_JUMP_IN nonzero means report error there is a jump into this
1099 contour from before the beginning of the contour.
1100 This is also done if STACK_LEVEL is nonzero. */
1103 fixup_gotos (thisblock, stack_level, cleanup_list, first_insn, dont_jump_in)
1104 struct nesting *thisblock;
1110 register struct goto_fixup *f, *prev;
1112 /* F is the fixup we are considering; PREV is the previous one. */
1113 /* We run this loop in two passes so that cleanups of exited blocks
1114 are run first, and blocks that are exited are marked so
1117 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1119 /* Test for a fixup that is inactive because it is already handled. */
1120 if (f->before_jump == 0)
1122 /* Delete inactive fixup from the chain, if that is easy to do. */
1124 prev->next = f->next;
1126 /* Has this fixup's target label been defined?
1127 If so, we can finalize it. */
1128 else if (PREV_INSN (f->target_rtl) != 0)
1130 register rtx cleanup_insns;
1132 /* If this fixup jumped into this contour from before the beginning
1133 of this contour, report an error. This code used to use
1134 the first non-label insn after f->target_rtl, but that's
1135 wrong since such can be added, by things like put_var_into_stack
1136 and have INSN_UIDs that are out of the range of the block. */
1137 /* ??? Bug: this does not detect jumping in through intermediate
1138 blocks that have stack levels or cleanups.
1139 It detects only a problem with the innermost block
1140 around the label. */
1142 && (dont_jump_in || stack_level || cleanup_list)
1143 && INSN_UID (first_insn) < INSN_UID (f->target_rtl)
1144 && INSN_UID (first_insn) > INSN_UID (f->before_jump)
1145 && ! DECL_ERROR_ISSUED (f->target))
1147 error_with_decl (f->target,
1148 "label `%s' used before containing binding contour");
1149 /* Prevent multiple errors for one label. */
1150 DECL_ERROR_ISSUED (f->target) = 1;
1153 /* We will expand the cleanups into a sequence of their own and
1154 then later on we will attach this new sequence to the insn
1155 stream just ahead of the actual jump insn. */
1159 /* Temporarily restore the lexical context where we will
1160 logically be inserting the fixup code. We do this for the
1161 sake of getting the debugging information right. */
1164 set_block (f->context);
1166 /* Expand the cleanups for blocks this jump exits. */
1167 if (f->cleanup_list_list)
1170 for (lists = f->cleanup_list_list; lists; lists = TREE_CHAIN (lists))
1171 /* Marked elements correspond to blocks that have been closed.
1172 Do their cleanups. */
1173 if (TREE_ADDRESSABLE (lists)
1174 && TREE_VALUE (lists) != 0)
1176 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1177 /* Pop any pushes done in the cleanups,
1178 in case function is about to return. */
1179 do_pending_stack_adjust ();
1183 /* Restore stack level for the biggest contour that this
1184 jump jumps out of. */
1186 emit_stack_restore (SAVE_BLOCK, f->stack_level, f->before_jump);
1188 /* Finish up the sequence containing the insns which implement the
1189 necessary cleanups, and then attach that whole sequence to the
1190 insn stream just ahead of the actual jump insn. Attaching it
1191 at that point insures that any cleanups which are in fact
1192 implicit C++ object destructions (which must be executed upon
1193 leaving the block) appear (to the debugger) to be taking place
1194 in an area of the generated code where the object(s) being
1195 destructed are still "in scope". */
1197 cleanup_insns = get_insns ();
1201 emit_insns_after (cleanup_insns, f->before_jump);
1208 /* For any still-undefined labels, do the cleanups for this block now.
1209 We must do this now since items in the cleanup list may go out
1210 of scope when the block ends. */
1211 for (prev = 0, f = goto_fixup_chain; f; prev = f, f = f->next)
1212 if (f->before_jump != 0
1213 && PREV_INSN (f->target_rtl) == 0
1214 /* Label has still not appeared. If we are exiting a block with
1215 a stack level to restore, that started before the fixup,
1216 mark this stack level as needing restoration
1217 when the fixup is later finalized. */
1219 /* Note: if THISBLOCK == 0 and we have a label that hasn't appeared, it
1220 means the label is undefined. That's erroneous, but possible. */
1221 && (thisblock->data.block.block_start_count
1222 <= f->block_start_count))
1224 tree lists = f->cleanup_list_list;
1227 for (; lists; lists = TREE_CHAIN (lists))
1228 /* If the following elt. corresponds to our containing block
1229 then the elt. must be for this block. */
1230 if (TREE_CHAIN (lists) == thisblock->data.block.outer_cleanups)
1234 set_block (f->context);
1235 expand_cleanups (TREE_VALUE (lists), NULL_TREE, 1, 1);
1236 do_pending_stack_adjust ();
1237 cleanup_insns = get_insns ();
1240 if (cleanup_insns != 0)
1242 = emit_insns_after (cleanup_insns, f->before_jump);
1244 f->cleanup_list_list = TREE_CHAIN (lists);
1248 f->stack_level = stack_level;
1252 /* Return the number of times character C occurs in string S. */
1254 n_occurrences (c, s)
1264 /* Generate RTL for an asm statement (explicit assembler code).
1265 BODY is a STRING_CST node containing the assembler code text,
1266 or an ADDR_EXPR containing a STRING_CST. */
1272 if (current_function_check_memory_usage)
1274 error ("`asm' cannot be used in function where memory usage is checked");
1278 if (TREE_CODE (body) == ADDR_EXPR)
1279 body = TREE_OPERAND (body, 0);
1281 emit_insn (gen_rtx_ASM_INPUT (VOIDmode,
1282 TREE_STRING_POINTER (body)));
1286 /* Generate RTL for an asm statement with arguments.
1287 STRING is the instruction template.
1288 OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
1289 Each output or input has an expression in the TREE_VALUE and
1290 a constraint-string in the TREE_PURPOSE.
1291 CLOBBERS is a list of STRING_CST nodes each naming a hard register
1292 that is clobbered by this insn.
1294 Not all kinds of lvalue that may appear in OUTPUTS can be stored directly.
1295 Some elements of OUTPUTS may be replaced with trees representing temporary
1296 values. The caller should copy those temporary values to the originally
1299 VOL nonzero means the insn is volatile; don't optimize it. */
1302 expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
1303 tree string, outputs, inputs, clobbers;
1308 rtvec argvec, constraints;
1310 int ninputs = list_length (inputs);
1311 int noutputs = list_length (outputs);
1316 /* Vector of RTX's of evaluated output operands. */
1317 rtx *output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1318 int *inout_opnum = (int *) alloca (noutputs * sizeof (int));
1319 rtx *real_output_rtx = (rtx *) alloca (noutputs * sizeof (rtx));
1320 enum machine_mode *inout_mode
1321 = (enum machine_mode *) alloca (noutputs * sizeof (enum machine_mode));
1322 /* The insn we have emitted. */
1325 /* An ASM with no outputs needs to be treated as volatile, for now. */
1329 if (current_function_check_memory_usage)
1331 error ("`asm' cannot be used with `-fcheck-memory-usage'");
1335 #ifdef MD_ASM_CLOBBERS
1336 /* Sometimes we wish to automatically clobber registers across an asm.
1337 Case in point is when the i386 backend moved from cc0 to a hard reg --
1338 maintaining source-level compatability means automatically clobbering
1339 the flags register. */
1340 MD_ASM_CLOBBERS (clobbers);
1343 if (current_function_check_memory_usage)
1345 error ("`asm' cannot be used in function where memory usage is checked");
1349 /* Count the number of meaningful clobbered registers, ignoring what
1350 we would ignore later. */
1352 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1354 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1356 i = decode_reg_name (regname);
1357 if (i >= 0 || i == -4)
1360 error ("unknown register name `%s' in `asm'", regname);
1365 /* Check that the number of alternatives is constant across all
1367 if (outputs || inputs)
1369 tree tmp = TREE_PURPOSE (outputs ? outputs : inputs);
1370 int nalternatives = n_occurrences (',', TREE_STRING_POINTER (tmp));
1373 if (nalternatives + 1 > MAX_RECOG_ALTERNATIVES)
1375 error ("too many alternatives in `asm'");
1382 const char *constraint = TREE_STRING_POINTER (TREE_PURPOSE (tmp));
1384 if (n_occurrences (',', constraint) != nalternatives)
1386 error ("operand constraints for `asm' differ in number of alternatives");
1390 if (TREE_CHAIN (tmp))
1391 tmp = TREE_CHAIN (tmp);
1393 tmp = next, next = 0;
1397 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1399 tree val = TREE_VALUE (tail);
1400 tree type = TREE_TYPE (val);
1409 /* If there's an erroneous arg, emit no insn. */
1410 if (TREE_TYPE (val) == error_mark_node)
1413 /* Make sure constraint has `=' and does not have `+'. Also, see
1414 if it allows any register. Be liberal on the latter test, since
1415 the worst that happens if we get it wrong is we issue an error
1418 c_len = strlen (TREE_STRING_POINTER (TREE_PURPOSE (tail)));
1419 constraint = TREE_STRING_POINTER (TREE_PURPOSE (tail));
1421 /* Allow the `=' or `+' to not be at the beginning of the string,
1422 since it wasn't explicitly documented that way, and there is a
1423 large body of code that puts it last. Swap the character to
1424 the front, so as not to uglify any place else. */
1428 if ((p = strchr (constraint, '=')) != NULL)
1430 if ((p = strchr (constraint, '+')) != NULL)
1433 error ("output operand constraint lacks `='");
1437 if (p != constraint)
1440 bcopy (constraint, constraint+1, p-constraint);
1443 warning ("output constraint `%c' for operand %d is not at the beginning", j, i);
1446 is_inout = constraint[0] == '+';
1447 /* Replace '+' with '='. */
1448 constraint[0] = '=';
1449 /* Make sure we can specify the matching operand. */
1450 if (is_inout && i > 9)
1452 error ("output operand constraint %d contains `+'", i);
1456 for (j = 1; j < c_len; j++)
1457 switch (constraint[j])
1461 error ("operand constraint contains '+' or '=' at illegal position.");
1465 if (i + 1 == ninputs + noutputs)
1467 error ("`%%' constraint used with last operand");
1472 case '?': case '!': case '*': case '&':
1473 case 'E': case 'F': case 'G': case 'H':
1474 case 's': case 'i': case 'n':
1475 case 'I': case 'J': case 'K': case 'L': case 'M':
1476 case 'N': case 'O': case 'P': case ',':
1477 #ifdef EXTRA_CONSTRAINT
1478 case 'Q': case 'R': case 'S': case 'T': case 'U':
1482 case '0': case '1': case '2': case '3': case '4':
1483 case '5': case '6': case '7': case '8': case '9':
1484 error ("matching constraint not valid in output operand");
1487 case 'V': case 'm': case 'o':
1492 /* ??? Before flow, auto inc/dec insns are not supposed to exist,
1493 excepting those that expand_call created. So match memory
1509 /* If an output operand is not a decl or indirect ref and our constraint
1510 allows a register, make a temporary to act as an intermediate.
1511 Make the asm insn write into that, then our caller will copy it to
1512 the real output operand. Likewise for promoted variables. */
1514 real_output_rtx[i] = NULL_RTX;
1515 if ((TREE_CODE (val) == INDIRECT_REF
1518 && (allows_mem || GET_CODE (DECL_RTL (val)) == REG)
1519 && ! (GET_CODE (DECL_RTL (val)) == REG
1520 && GET_MODE (DECL_RTL (val)) != TYPE_MODE (type)))
1525 mark_addressable (TREE_VALUE (tail));
1528 = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode,
1529 EXPAND_MEMORY_USE_WO);
1531 if (! allows_reg && GET_CODE (output_rtx[i]) != MEM)
1532 error ("output number %d not directly addressable", i);
1533 if (! allows_mem && GET_CODE (output_rtx[i]) == MEM)
1535 real_output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1536 output_rtx[i] = gen_reg_rtx (GET_MODE (output_rtx[i]));
1538 emit_move_insn (output_rtx[i], real_output_rtx[i]);
1543 output_rtx[i] = assign_temp (type, 0, 0, 1);
1544 TREE_VALUE (tail) = make_tree (type, output_rtx[i]);
1549 inout_mode[ninout] = TYPE_MODE (TREE_TYPE (TREE_VALUE (tail)));
1550 inout_opnum[ninout++] = i;
1555 if (ninputs + noutputs > MAX_RECOG_OPERANDS)
1557 error ("more than %d operands in `asm'", MAX_RECOG_OPERANDS);
1561 /* Make vectors for the expression-rtx and constraint strings. */
1563 argvec = rtvec_alloc (ninputs);
1564 constraints = rtvec_alloc (ninputs);
1566 body = gen_rtx_ASM_OPERANDS (VOIDmode, TREE_STRING_POINTER (string),
1567 empty_string, 0, argvec, constraints,
1570 MEM_VOLATILE_P (body) = vol;
1572 /* Eval the inputs and put them into ARGVEC.
1573 Put their constraints into ASM_INPUTs and store in CONSTRAINTS. */
1576 for (tail = inputs; tail; tail = TREE_CHAIN (tail))
1579 int allows_reg = 0, allows_mem = 0;
1580 char *constraint, *orig_constraint;
1584 /* If there's an erroneous arg, emit no insn,
1585 because the ASM_INPUT would get VOIDmode
1586 and that could cause a crash in reload. */
1587 if (TREE_TYPE (TREE_VALUE (tail)) == error_mark_node)
1590 /* ??? Can this happen, and does the error message make any sense? */
1591 if (TREE_PURPOSE (tail) == NULL_TREE)
1593 error ("hard register `%s' listed as input operand to `asm'",
1594 TREE_STRING_POINTER (TREE_VALUE (tail)) );
1598 c_len = strlen (TREE_STRING_POINTER (TREE_PURPOSE (tail)));
1599 constraint = TREE_STRING_POINTER (TREE_PURPOSE (tail));
1600 orig_constraint = constraint;
1602 /* Make sure constraint has neither `=', `+', nor '&'. */
1604 for (j = 0; j < c_len; j++)
1605 switch (constraint[j])
1607 case '+': case '=': case '&':
1608 if (constraint == orig_constraint)
1610 error ("input operand constraint contains `%c'",
1617 if (constraint == orig_constraint
1618 && i + 1 == ninputs - ninout)
1620 error ("`%%' constraint used with last operand");
1625 case 'V': case 'm': case 'o':
1630 case '?': case '!': case '*':
1631 case 'E': case 'F': case 'G': case 'H': case 'X':
1632 case 's': case 'i': case 'n':
1633 case 'I': case 'J': case 'K': case 'L': case 'M':
1634 case 'N': case 'O': case 'P': case ',':
1635 #ifdef EXTRA_CONSTRAINT
1636 case 'Q': case 'R': case 'S': case 'T': case 'U':
1640 /* Whether or not a numeric constraint allows a register is
1641 decided by the matching constraint, and so there is no need
1642 to do anything special with them. We must handle them in
1643 the default case, so that we don't unnecessarily force
1644 operands to memory. */
1645 case '0': case '1': case '2': case '3': case '4':
1646 case '5': case '6': case '7': case '8': case '9':
1647 if (constraint[j] >= '0' + noutputs)
1650 ("matching constraint references invalid operand number");
1654 /* Try and find the real constraint for this dup. */
1655 if ((j == 0 && c_len == 1)
1656 || (j == 1 && c_len == 2 && constraint[0] == '%'))
1660 for (j = constraint[j] - '0'; j > 0; --j)
1663 c_len = strlen (TREE_STRING_POINTER (TREE_PURPOSE (o)));
1664 constraint = TREE_STRING_POINTER (TREE_PURPOSE (o));
1669 /* ... fall through ... */
1682 if (! allows_reg && allows_mem)
1683 mark_addressable (TREE_VALUE (tail));
1685 op = expand_expr (TREE_VALUE (tail), NULL_RTX, VOIDmode, 0);
1687 if (asm_operand_ok (op, constraint) <= 0)
1690 op = force_reg (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))), op);
1691 else if (!allows_mem)
1692 warning ("asm operand %d probably doesn't match constraints", i);
1693 else if (CONSTANT_P (op))
1694 op = force_const_mem (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1696 else if (GET_CODE (op) == REG
1697 || GET_CODE (op) == SUBREG
1698 || GET_CODE (op) == CONCAT)
1700 tree type = TREE_TYPE (TREE_VALUE (tail));
1701 rtx memloc = assign_temp (type, 1, 1, 1);
1703 emit_move_insn (memloc, op);
1707 else if (GET_CODE (op) == MEM && MEM_VOLATILE_P (op))
1708 /* We won't recognize volatile memory as available a
1709 memory_operand at this point. Ignore it. */
1711 else if (queued_subexp_p (op))
1714 /* ??? Leave this only until we have experience with what
1715 happens in combine and elsewhere when constraints are
1717 warning ("asm operand %d probably doesn't match constraints", i);
1719 XVECEXP (body, 3, i) = op;
1721 XVECEXP (body, 4, i) /* constraints */
1722 = gen_rtx_ASM_INPUT (TYPE_MODE (TREE_TYPE (TREE_VALUE (tail))),
1727 /* Protect all the operands from the queue now that they have all been
1730 for (i = 0; i < ninputs - ninout; i++)
1731 XVECEXP (body, 3, i) = protect_from_queue (XVECEXP (body, 3, i), 0);
1733 for (i = 0; i < noutputs; i++)
1734 output_rtx[i] = protect_from_queue (output_rtx[i], 1);
1736 /* For in-out operands, copy output rtx to input rtx. */
1737 for (i = 0; i < ninout; i++)
1739 int j = inout_opnum[i];
1741 XVECEXP (body, 3, ninputs - ninout + i) /* argvec */
1743 XVECEXP (body, 4, ninputs - ninout + i) /* constraints */
1744 = gen_rtx_ASM_INPUT (inout_mode[i], digit_strings[j]);
1747 /* Now, for each output, construct an rtx
1748 (set OUTPUT (asm_operands INSN OUTPUTNUMBER OUTPUTCONSTRAINT
1749 ARGVEC CONSTRAINTS))
1750 If there is more than one, put them inside a PARALLEL. */
1752 if (noutputs == 1 && nclobbers == 0)
1754 XSTR (body, 1) = TREE_STRING_POINTER (TREE_PURPOSE (outputs));
1755 insn = emit_insn (gen_rtx_SET (VOIDmode, output_rtx[0], body));
1758 else if (noutputs == 0 && nclobbers == 0)
1760 /* No output operands: put in a raw ASM_OPERANDS rtx. */
1761 insn = emit_insn (body);
1772 body = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num + nclobbers));
1774 /* For each output operand, store a SET. */
1775 for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
1777 XVECEXP (body, 0, i)
1778 = gen_rtx_SET (VOIDmode,
1780 gen_rtx_ASM_OPERANDS
1782 TREE_STRING_POINTER (string),
1783 TREE_STRING_POINTER (TREE_PURPOSE (tail)),
1784 i, argvec, constraints,
1787 MEM_VOLATILE_P (SET_SRC (XVECEXP (body, 0, i))) = vol;
1790 /* If there are no outputs (but there are some clobbers)
1791 store the bare ASM_OPERANDS into the PARALLEL. */
1794 XVECEXP (body, 0, i++) = obody;
1796 /* Store (clobber REG) for each clobbered register specified. */
1798 for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
1800 const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
1801 int j = decode_reg_name (regname);
1805 if (j == -3) /* `cc', which is not a register */
1808 if (j == -4) /* `memory', don't cache memory across asm */
1810 XVECEXP (body, 0, i++)
1811 = gen_rtx_CLOBBER (VOIDmode,
1814 gen_rtx_SCRATCH (VOIDmode)));
1818 /* Ignore unknown register, error already signaled. */
1822 /* Use QImode since that's guaranteed to clobber just one reg. */
1823 XVECEXP (body, 0, i++)
1824 = gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (QImode, j));
1827 insn = emit_insn (body);
1830 /* For any outputs that needed reloading into registers, spill them
1831 back to where they belong. */
1832 for (i = 0; i < noutputs; ++i)
1833 if (real_output_rtx[i])
1834 emit_move_insn (real_output_rtx[i], output_rtx[i]);
1839 /* Generate RTL to evaluate the expression EXP
1840 and remember it in case this is the VALUE in a ({... VALUE; }) constr. */
1843 expand_expr_stmt (exp)
1846 /* If -W, warn about statements with no side effects,
1847 except for an explicit cast to void (e.g. for assert()), and
1848 except inside a ({...}) where they may be useful. */
1849 if (expr_stmts_for_value == 0 && exp != error_mark_node)
1851 if (! TREE_SIDE_EFFECTS (exp) && (extra_warnings || warn_unused)
1852 && !(TREE_CODE (exp) == CONVERT_EXPR
1853 && TREE_TYPE (exp) == void_type_node))
1854 warning_with_file_and_line (emit_filename, emit_lineno,
1855 "statement with no effect");
1856 else if (warn_unused)
1857 warn_if_unused_value (exp);
1860 /* If EXP is of function type and we are expanding statements for
1861 value, convert it to pointer-to-function. */
1862 if (expr_stmts_for_value && TREE_CODE (TREE_TYPE (exp)) == FUNCTION_TYPE)
1863 exp = build1 (ADDR_EXPR, build_pointer_type (TREE_TYPE (exp)), exp);
1865 last_expr_type = TREE_TYPE (exp);
1866 last_expr_value = expand_expr (exp,
1867 (expr_stmts_for_value
1868 ? NULL_RTX : const0_rtx),
1871 /* If all we do is reference a volatile value in memory,
1872 copy it to a register to be sure it is actually touched. */
1873 if (last_expr_value != 0 && GET_CODE (last_expr_value) == MEM
1874 && TREE_THIS_VOLATILE (exp))
1876 if (TYPE_MODE (TREE_TYPE (exp)) == VOIDmode)
1878 else if (TYPE_MODE (TREE_TYPE (exp)) != BLKmode)
1879 copy_to_reg (last_expr_value);
1882 rtx lab = gen_label_rtx ();
1884 /* Compare the value with itself to reference it. */
1885 emit_cmp_and_jump_insns (last_expr_value, last_expr_value, EQ,
1886 expand_expr (TYPE_SIZE (last_expr_type),
1887 NULL_RTX, VOIDmode, 0),
1889 TYPE_ALIGN (last_expr_type) / BITS_PER_UNIT,
1895 /* If this expression is part of a ({...}) and is in memory, we may have
1896 to preserve temporaries. */
1897 preserve_temp_slots (last_expr_value);
1899 /* Free any temporaries used to evaluate this expression. Any temporary
1900 used as a result of this expression will already have been preserved
1907 /* Warn if EXP contains any computations whose results are not used.
1908 Return 1 if a warning is printed; 0 otherwise. */
1911 warn_if_unused_value (exp)
1914 if (TREE_USED (exp))
1917 switch (TREE_CODE (exp))
1919 case PREINCREMENT_EXPR:
1920 case POSTINCREMENT_EXPR:
1921 case PREDECREMENT_EXPR:
1922 case POSTDECREMENT_EXPR:
1927 case METHOD_CALL_EXPR:
1929 case TRY_CATCH_EXPR:
1930 case WITH_CLEANUP_EXPR:
1932 /* We don't warn about COND_EXPR because it may be a useful
1933 construct if either arm contains a side effect. */
1938 /* For a binding, warn if no side effect within it. */
1939 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1942 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1944 case TRUTH_ORIF_EXPR:
1945 case TRUTH_ANDIF_EXPR:
1946 /* In && or ||, warn if 2nd operand has no side effect. */
1947 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1950 if (TREE_NO_UNUSED_WARNING (exp))
1952 if (warn_if_unused_value (TREE_OPERAND (exp, 0)))
1954 /* Let people do `(foo (), 0)' without a warning. */
1955 if (TREE_CONSTANT (TREE_OPERAND (exp, 1)))
1957 return warn_if_unused_value (TREE_OPERAND (exp, 1));
1961 case NON_LVALUE_EXPR:
1962 /* Don't warn about values cast to void. */
1963 if (TREE_TYPE (exp) == void_type_node)
1965 /* Don't warn about conversions not explicit in the user's program. */
1966 if (TREE_NO_UNUSED_WARNING (exp))
1968 /* Assignment to a cast usually results in a cast of a modify.
1969 Don't complain about that. There can be an arbitrary number of
1970 casts before the modify, so we must loop until we find the first
1971 non-cast expression and then test to see if that is a modify. */
1973 tree tem = TREE_OPERAND (exp, 0);
1975 while (TREE_CODE (tem) == CONVERT_EXPR || TREE_CODE (tem) == NOP_EXPR)
1976 tem = TREE_OPERAND (tem, 0);
1978 if (TREE_CODE (tem) == MODIFY_EXPR || TREE_CODE (tem) == INIT_EXPR
1979 || TREE_CODE (tem) == CALL_EXPR)
1985 /* Don't warn about automatic dereferencing of references, since
1986 the user cannot control it. */
1987 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == REFERENCE_TYPE)
1988 return warn_if_unused_value (TREE_OPERAND (exp, 0));
1989 /* ... fall through ... */
1992 /* Referencing a volatile value is a side effect, so don't warn. */
1994 || TREE_CODE_CLASS (TREE_CODE (exp)) == 'r')
1995 && TREE_THIS_VOLATILE (exp))
1998 warning_with_file_and_line (emit_filename, emit_lineno,
1999 "value computed is not used");
2004 /* Clear out the memory of the last expression evaluated. */
2012 /* Begin a statement which will return a value.
2013 Return the RTL_EXPR for this statement expr.
2014 The caller must save that value and pass it to expand_end_stmt_expr. */
2017 expand_start_stmt_expr ()
2022 /* Make the RTL_EXPR node temporary, not momentary,
2023 so that rtl_expr_chain doesn't become garbage. */
2024 momentary = suspend_momentary ();
2025 t = make_node (RTL_EXPR);
2026 resume_momentary (momentary);
2027 do_pending_stack_adjust ();
2028 start_sequence_for_rtl_expr (t);
2030 expr_stmts_for_value++;
2034 /* Restore the previous state at the end of a statement that returns a value.
2035 Returns a tree node representing the statement's value and the
2036 insns to compute the value.
2038 The nodes of that expression have been freed by now, so we cannot use them.
2039 But we don't want to do that anyway; the expression has already been
2040 evaluated and now we just want to use the value. So generate a RTL_EXPR
2041 with the proper type and RTL value.
2043 If the last substatement was not an expression,
2044 return something with type `void'. */
2047 expand_end_stmt_expr (t)
2052 if (last_expr_type == 0)
2054 last_expr_type = void_type_node;
2055 last_expr_value = const0_rtx;
2057 else if (last_expr_value == 0)
2058 /* There are some cases where this can happen, such as when the
2059 statement is void type. */
2060 last_expr_value = const0_rtx;
2061 else if (GET_CODE (last_expr_value) != REG && ! CONSTANT_P (last_expr_value))
2062 /* Remove any possible QUEUED. */
2063 last_expr_value = protect_from_queue (last_expr_value, 0);
2067 TREE_TYPE (t) = last_expr_type;
2068 RTL_EXPR_RTL (t) = last_expr_value;
2069 RTL_EXPR_SEQUENCE (t) = get_insns ();
2071 rtl_expr_chain = tree_cons (NULL_TREE, t, rtl_expr_chain);
2075 /* Don't consider deleting this expr or containing exprs at tree level. */
2076 TREE_SIDE_EFFECTS (t) = 1;
2077 /* Propagate volatility of the actual RTL expr. */
2078 TREE_THIS_VOLATILE (t) = volatile_refs_p (last_expr_value);
2081 expr_stmts_for_value--;
2086 /* Generate RTL for the start of an if-then. COND is the expression
2087 whose truth should be tested.
2089 If EXITFLAG is nonzero, this conditional is visible to
2090 `exit_something'. */
2093 expand_start_cond (cond, exitflag)
2097 struct nesting *thiscond = ALLOC_NESTING ();
2099 /* Make an entry on cond_stack for the cond we are entering. */
2101 thiscond->next = cond_stack;
2102 thiscond->all = nesting_stack;
2103 thiscond->depth = ++nesting_depth;
2104 thiscond->data.cond.next_label = gen_label_rtx ();
2105 /* Before we encounter an `else', we don't need a separate exit label
2106 unless there are supposed to be exit statements
2107 to exit this conditional. */
2108 thiscond->exit_label = exitflag ? gen_label_rtx () : 0;
2109 thiscond->data.cond.endif_label = thiscond->exit_label;
2110 cond_stack = thiscond;
2111 nesting_stack = thiscond;
2113 do_jump (cond, thiscond->data.cond.next_label, NULL_RTX);
2116 /* Generate RTL between then-clause and the elseif-clause
2117 of an if-then-elseif-.... */
2120 expand_start_elseif (cond)
2123 if (cond_stack->data.cond.endif_label == 0)
2124 cond_stack->data.cond.endif_label = gen_label_rtx ();
2125 emit_jump (cond_stack->data.cond.endif_label);
2126 emit_label (cond_stack->data.cond.next_label);
2127 cond_stack->data.cond.next_label = gen_label_rtx ();
2128 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2131 /* Generate RTL between the then-clause and the else-clause
2132 of an if-then-else. */
2135 expand_start_else ()
2137 if (cond_stack->data.cond.endif_label == 0)
2138 cond_stack->data.cond.endif_label = gen_label_rtx ();
2140 emit_jump (cond_stack->data.cond.endif_label);
2141 emit_label (cond_stack->data.cond.next_label);
2142 cond_stack->data.cond.next_label = 0; /* No more _else or _elseif calls. */
2145 /* After calling expand_start_else, turn this "else" into an "else if"
2146 by providing another condition. */
2149 expand_elseif (cond)
2152 cond_stack->data.cond.next_label = gen_label_rtx ();
2153 do_jump (cond, cond_stack->data.cond.next_label, NULL_RTX);
2156 /* Generate RTL for the end of an if-then.
2157 Pop the record for it off of cond_stack. */
2162 struct nesting *thiscond = cond_stack;
2164 do_pending_stack_adjust ();
2165 if (thiscond->data.cond.next_label)
2166 emit_label (thiscond->data.cond.next_label);
2167 if (thiscond->data.cond.endif_label)
2168 emit_label (thiscond->data.cond.endif_label);
2170 POPSTACK (cond_stack);
2176 /* Generate RTL for the start of a loop. EXIT_FLAG is nonzero if this
2177 loop should be exited by `exit_something'. This is a loop for which
2178 `expand_continue' will jump to the top of the loop.
2180 Make an entry on loop_stack to record the labels associated with
2184 expand_start_loop (exit_flag)
2187 register struct nesting *thisloop = ALLOC_NESTING ();
2189 /* Make an entry on loop_stack for the loop we are entering. */
2191 thisloop->next = loop_stack;
2192 thisloop->all = nesting_stack;
2193 thisloop->depth = ++nesting_depth;
2194 thisloop->data.loop.start_label = gen_label_rtx ();
2195 thisloop->data.loop.end_label = gen_label_rtx ();
2196 thisloop->data.loop.alt_end_label = 0;
2197 thisloop->data.loop.continue_label = thisloop->data.loop.start_label;
2198 thisloop->exit_label = exit_flag ? thisloop->data.loop.end_label : 0;
2199 loop_stack = thisloop;
2200 nesting_stack = thisloop;
2202 do_pending_stack_adjust ();
2204 emit_note (NULL_PTR, NOTE_INSN_LOOP_BEG);
2205 emit_label (thisloop->data.loop.start_label);
2210 /* Like expand_start_loop but for a loop where the continuation point
2211 (for expand_continue_loop) will be specified explicitly. */
2214 expand_start_loop_continue_elsewhere (exit_flag)
2217 struct nesting *thisloop = expand_start_loop (exit_flag);
2218 loop_stack->data.loop.continue_label = gen_label_rtx ();
2222 /* Specify the continuation point for a loop started with
2223 expand_start_loop_continue_elsewhere.
2224 Use this at the point in the code to which a continue statement
2228 expand_loop_continue_here ()
2230 do_pending_stack_adjust ();
2231 emit_note (NULL_PTR, NOTE_INSN_LOOP_CONT);
2232 emit_label (loop_stack->data.loop.continue_label);
2235 /* Finish a loop. Generate a jump back to the top and the loop-exit label.
2236 Pop the block off of loop_stack. */
2241 rtx start_label = loop_stack->data.loop.start_label;
2242 rtx insn = get_last_insn ();
2243 int needs_end_jump = 1;
2245 /* Mark the continue-point at the top of the loop if none elsewhere. */
2246 if (start_label == loop_stack->data.loop.continue_label)
2247 emit_note_before (NOTE_INSN_LOOP_CONT, start_label);
2249 do_pending_stack_adjust ();
2251 /* If optimizing, perhaps reorder the loop.
2252 First, try to use a condjump near the end.
2253 expand_exit_loop_if_false ends loops with unconditional jumps,
2256 if (test) goto label;
2258 goto loop_stack->data.loop.end_label
2262 If we find such a pattern, we can end the loop earlier. */
2265 && GET_CODE (insn) == CODE_LABEL
2266 && LABEL_NAME (insn) == NULL
2267 && GET_CODE (PREV_INSN (insn)) == BARRIER)
2270 rtx jump = PREV_INSN (PREV_INSN (label));
2272 if (GET_CODE (jump) == JUMP_INSN
2273 && GET_CODE (PATTERN (jump)) == SET
2274 && SET_DEST (PATTERN (jump)) == pc_rtx
2275 && GET_CODE (SET_SRC (PATTERN (jump))) == LABEL_REF
2276 && (XEXP (SET_SRC (PATTERN (jump)), 0)
2277 == loop_stack->data.loop.end_label))
2281 /* The test might be complex and reference LABEL multiple times,
2282 like the loop in loop_iterations to set vtop. To handle this,
2284 insn = PREV_INSN (label);
2285 reorder_insns (label, label, start_label);
2287 for (prev = PREV_INSN (jump); ; prev = PREV_INSN (prev))
2289 /* We ignore line number notes, but if we see any other note,
2290 in particular NOTE_INSN_BLOCK_*, NOTE_INSN_EH_REGION_*,
2291 NOTE_INSN_LOOP_*, we disable this optimization. */
2292 if (GET_CODE (prev) == NOTE)
2294 if (NOTE_LINE_NUMBER (prev) < 0)
2298 if (GET_CODE (prev) == CODE_LABEL)
2300 if (GET_CODE (prev) == JUMP_INSN)
2302 if (GET_CODE (PATTERN (prev)) == SET
2303 && SET_DEST (PATTERN (prev)) == pc_rtx
2304 && GET_CODE (SET_SRC (PATTERN (prev))) == IF_THEN_ELSE
2305 && (GET_CODE (XEXP (SET_SRC (PATTERN (prev)), 1))
2307 && XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0) == label)
2309 XEXP (XEXP (SET_SRC (PATTERN (prev)), 1), 0)
2311 emit_note_after (NOTE_INSN_LOOP_END, prev);
2320 /* If the loop starts with a loop exit, roll that to the end where
2321 it will optimize together with the jump back.
2323 We look for the conditional branch to the exit, except that once
2324 we find such a branch, we don't look past 30 instructions.
2326 In more detail, if the loop presently looks like this (in pseudo-C):
2329 if (test) goto end_label;
2334 transform it to look like:
2340 if (test) goto end_label;
2341 goto newstart_label;
2344 Here, the `test' may actually consist of some reasonably complex
2345 code, terminating in a test. */
2350 ! (GET_CODE (insn) == JUMP_INSN
2351 && GET_CODE (PATTERN (insn)) == SET
2352 && SET_DEST (PATTERN (insn)) == pc_rtx
2353 && GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE))
2357 rtx last_test_insn = NULL_RTX;
2359 /* Scan insns from the top of the loop looking for a qualified
2360 conditional exit. */
2361 for (insn = NEXT_INSN (loop_stack->data.loop.start_label); insn;
2362 insn = NEXT_INSN (insn))
2364 if (GET_CODE (insn) == NOTE)
2367 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2368 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2369 /* The code that actually moves the exit test will
2370 carefully leave BLOCK notes in their original
2371 location. That means, however, that we can't debug
2372 the exit test itself. So, we refuse to move code
2373 containing BLOCK notes at low optimization levels. */
2376 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_BEG)
2378 else if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_EH_REGION_END)
2382 /* We've come to the end of an EH region, but
2383 never saw the beginning of that region. That
2384 means that an EH region begins before the top
2385 of the loop, and ends in the middle of it. The
2386 existence of such a situation violates a basic
2387 assumption in this code, since that would imply
2388 that even when EH_REGIONS is zero, we might
2389 move code out of an exception region. */
2393 /* We must not walk into a nested loop. */
2394 if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
2397 /* We already know this INSN is a NOTE, so there's no
2398 point in looking at it to see if it's a JUMP. */
2402 if (GET_CODE (insn) == JUMP_INSN || GET_CODE (insn) == INSN)
2405 if (last_test_insn && num_insns > 30)
2409 /* We don't want to move a partial EH region. Consider:
2423 This isn't legal C++, but here's what it's supposed to
2424 mean: if cond() is true, stop looping. Otherwise,
2425 call bar, and keep looping. In addition, if cond
2426 throws an exception, catch it and keep looping. Such
2427 constructs are certainy legal in LISP.
2429 We should not move the `if (cond()) 0' test since then
2430 the EH-region for the try-block would be broken up.
2431 (In this case we would the EH_BEG note for the `try'
2432 and `if cond()' but not the call to bar() or the
2435 So we don't look for tests within an EH region. */
2438 if (GET_CODE (insn) == JUMP_INSN
2439 && GET_CODE (PATTERN (insn)) == SET
2440 && SET_DEST (PATTERN (insn)) == pc_rtx)
2442 /* This is indeed a jump. */
2443 rtx dest1 = NULL_RTX;
2444 rtx dest2 = NULL_RTX;
2445 rtx potential_last_test;
2446 if (GET_CODE (SET_SRC (PATTERN (insn))) == IF_THEN_ELSE)
2448 /* A conditional jump. */
2449 dest1 = XEXP (SET_SRC (PATTERN (insn)), 1);
2450 dest2 = XEXP (SET_SRC (PATTERN (insn)), 2);
2451 potential_last_test = insn;
2455 /* An unconditional jump. */
2456 dest1 = SET_SRC (PATTERN (insn));
2457 /* Include the BARRIER after the JUMP. */
2458 potential_last_test = NEXT_INSN (insn);
2462 if (dest1 && GET_CODE (dest1) == LABEL_REF
2463 && ((XEXP (dest1, 0)
2464 == loop_stack->data.loop.alt_end_label)
2466 == loop_stack->data.loop.end_label)))
2468 last_test_insn = potential_last_test;
2472 /* If this was a conditional jump, there may be
2473 another label at which we should look. */
2480 if (last_test_insn != 0 && last_test_insn != get_last_insn ())
2482 /* We found one. Move everything from there up
2483 to the end of the loop, and add a jump into the loop
2484 to jump to there. */
2485 register rtx newstart_label = gen_label_rtx ();
2486 register rtx start_move = start_label;
2489 /* If the start label is preceded by a NOTE_INSN_LOOP_CONT note,
2490 then we want to move this note also. */
2491 if (GET_CODE (PREV_INSN (start_move)) == NOTE
2492 && (NOTE_LINE_NUMBER (PREV_INSN (start_move))
2493 == NOTE_INSN_LOOP_CONT))
2494 start_move = PREV_INSN (start_move);
2496 emit_label_after (newstart_label, PREV_INSN (start_move));
2498 /* Actually move the insns. Start at the beginning, and
2499 keep copying insns until we've copied the
2501 for (insn = start_move; insn; insn = next_insn)
2503 /* Figure out which insn comes after this one. We have
2504 to do this before we move INSN. */
2505 if (insn == last_test_insn)
2506 /* We've moved all the insns. */
2507 next_insn = NULL_RTX;
2509 next_insn = NEXT_INSN (insn);
2511 if (GET_CODE (insn) == NOTE
2512 && (NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_BEG
2513 || NOTE_LINE_NUMBER (insn) == NOTE_INSN_BLOCK_END))
2514 /* We don't want to move NOTE_INSN_BLOCK_BEGs or
2515 NOTE_INSN_BLOCK_ENDs because the correct generation
2516 of debugging information depends on these appearing
2517 in the same order in the RTL and in the tree
2518 structure, where they are represented as BLOCKs.
2519 So, we don't move block notes. Of course, moving
2520 the code inside the block is likely to make it
2521 impossible to debug the instructions in the exit
2522 test, but such is the price of optimization. */
2525 /* Move the INSN. */
2526 reorder_insns (insn, insn, get_last_insn ());
2529 emit_jump_insn_after (gen_jump (start_label),
2530 PREV_INSN (newstart_label));
2531 emit_barrier_after (PREV_INSN (newstart_label));
2532 start_label = newstart_label;
2538 emit_jump (start_label);
2539 emit_note (NULL_PTR, NOTE_INSN_LOOP_END);
2541 emit_label (loop_stack->data.loop.end_label);
2543 POPSTACK (loop_stack);
2548 /* Generate a jump to the current loop's continue-point.
2549 This is usually the top of the loop, but may be specified
2550 explicitly elsewhere. If not currently inside a loop,
2551 return 0 and do nothing; caller will print an error message. */
2554 expand_continue_loop (whichloop)
2555 struct nesting *whichloop;
2559 whichloop = loop_stack;
2562 expand_goto_internal (NULL_TREE, whichloop->data.loop.continue_label,
2567 /* Generate a jump to exit the current loop. If not currently inside a loop,
2568 return 0 and do nothing; caller will print an error message. */
2571 expand_exit_loop (whichloop)
2572 struct nesting *whichloop;
2576 whichloop = loop_stack;
2579 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label, NULL_RTX);
2583 /* Generate a conditional jump to exit the current loop if COND
2584 evaluates to zero. If not currently inside a loop,
2585 return 0 and do nothing; caller will print an error message. */
2588 expand_exit_loop_if_false (whichloop, cond)
2589 struct nesting *whichloop;
2592 rtx label = gen_label_rtx ();
2597 whichloop = loop_stack;
2600 /* In order to handle fixups, we actually create a conditional jump
2601 around a unconditional branch to exit the loop. If fixups are
2602 necessary, they go before the unconditional branch. */
2605 do_jump (cond, NULL_RTX, label);
2606 last_insn = get_last_insn ();
2607 if (GET_CODE (last_insn) == CODE_LABEL)
2608 whichloop->data.loop.alt_end_label = last_insn;
2609 expand_goto_internal (NULL_TREE, whichloop->data.loop.end_label,
2616 /* Return nonzero if the loop nest is empty. Else return zero. */
2619 stmt_loop_nest_empty ()
2621 /* cfun->stmt can be NULL if we are building a call to get the
2622 EH context for a setjmp/longjmp EH target and the current
2623 function was a deferred inline function. */
2624 return (cfun->stmt == NULL || loop_stack == NULL);
2627 /* Return non-zero if we should preserve sub-expressions as separate
2628 pseudos. We never do so if we aren't optimizing. We always do so
2629 if -fexpensive-optimizations.
2631 Otherwise, we only do so if we are in the "early" part of a loop. I.e.,
2632 the loop may still be a small one. */
2635 preserve_subexpressions_p ()
2639 if (flag_expensive_optimizations)
2642 if (optimize == 0 || cfun == 0 || cfun->stmt == 0 || loop_stack == 0)
2645 insn = get_last_insn_anywhere ();
2648 && (INSN_UID (insn) - INSN_UID (loop_stack->data.loop.start_label)
2649 < n_non_fixed_regs * 3));
2653 /* Generate a jump to exit the current loop, conditional, binding contour
2654 or case statement. Not all such constructs are visible to this function,
2655 only those started with EXIT_FLAG nonzero. Individual languages use
2656 the EXIT_FLAG parameter to control which kinds of constructs you can
2659 If not currently inside anything that can be exited,
2660 return 0 and do nothing; caller will print an error message. */
2663 expand_exit_something ()
2667 for (n = nesting_stack; n; n = n->all)
2668 if (n->exit_label != 0)
2670 expand_goto_internal (NULL_TREE, n->exit_label, NULL_RTX);
2677 /* Generate RTL to return from the current function, with no value.
2678 (That is, we do not do anything about returning any value.) */
2681 expand_null_return ()
2683 struct nesting *block = block_stack;
2684 rtx last_insn = get_last_insn ();
2686 /* If this function was declared to return a value, but we
2687 didn't, clobber the return registers so that they are not
2688 propogated live to the rest of the function. */
2689 clobber_return_register ();
2691 /* Does any pending block have cleanups? */
2692 while (block && block->data.block.cleanups == 0)
2693 block = block->next;
2695 /* If yes, use a goto to return, since that runs cleanups. */
2697 expand_null_return_1 (last_insn, block != 0);
2700 /* Generate RTL to return from the current function, with value VAL. */
2703 expand_value_return (val)
2706 struct nesting *block = block_stack;
2707 rtx last_insn = get_last_insn ();
2708 rtx return_reg = DECL_RTL (DECL_RESULT (current_function_decl));
2710 /* Copy the value to the return location
2711 unless it's already there. */
2713 if (return_reg != val)
2715 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
2716 #ifdef PROMOTE_FUNCTION_RETURN
2717 int unsignedp = TREE_UNSIGNED (type);
2718 enum machine_mode old_mode
2719 = DECL_MODE (DECL_RESULT (current_function_decl));
2720 enum machine_mode mode
2721 = promote_mode (type, old_mode, &unsignedp, 1);
2723 if (mode != old_mode)
2724 val = convert_modes (mode, old_mode, val, unsignedp);
2726 if (GET_CODE (return_reg) == PARALLEL)
2727 emit_group_load (return_reg, val, int_size_in_bytes (type),
2730 emit_move_insn (return_reg, val);
2733 /* Does any pending block have cleanups? */
2735 while (block && block->data.block.cleanups == 0)
2736 block = block->next;
2738 /* If yes, use a goto to return, since that runs cleanups.
2739 Use LAST_INSN to put cleanups *before* the move insn emitted above. */
2741 expand_null_return_1 (last_insn, block != 0);
2744 /* Output a return with no value. If LAST_INSN is nonzero,
2745 pretend that the return takes place after LAST_INSN.
2746 If USE_GOTO is nonzero then don't use a return instruction;
2747 go to the return label instead. This causes any cleanups
2748 of pending blocks to be executed normally. */
2751 expand_null_return_1 (last_insn, use_goto)
2755 rtx end_label = cleanup_label ? cleanup_label : return_label;
2757 clear_pending_stack_adjust ();
2758 do_pending_stack_adjust ();
2761 /* PCC-struct return always uses an epilogue. */
2762 if (current_function_returns_pcc_struct || use_goto)
2765 end_label = return_label = gen_label_rtx ();
2766 expand_goto_internal (NULL_TREE, end_label, last_insn);
2770 /* Otherwise output a simple return-insn if one is available,
2771 unless it won't do the job. */
2773 if (HAVE_return && use_goto == 0 && cleanup_label == 0)
2775 emit_jump_insn (gen_return ());
2781 /* Otherwise jump to the epilogue. */
2782 expand_goto_internal (NULL_TREE, end_label, last_insn);
2785 /* Generate RTL to evaluate the expression RETVAL and return it
2786 from the current function. */
2789 expand_return (retval)
2792 /* If there are any cleanups to be performed, then they will
2793 be inserted following LAST_INSN. It is desirable
2794 that the last_insn, for such purposes, should be the
2795 last insn before computing the return value. Otherwise, cleanups
2796 which call functions can clobber the return value. */
2797 /* ??? rms: I think that is erroneous, because in C++ it would
2798 run destructors on variables that might be used in the subsequent
2799 computation of the return value. */
2801 rtx result_rtl = DECL_RTL (DECL_RESULT (current_function_decl));
2802 register rtx val = 0;
2809 /* If function wants no value, give it none. */
2810 if (TREE_CODE (TREE_TYPE (TREE_TYPE (current_function_decl))) == VOID_TYPE)
2812 expand_expr (retval, NULL_RTX, VOIDmode, 0);
2814 expand_null_return ();
2818 /* Are any cleanups needed? E.g. C++ destructors to be run? */
2819 /* This is not sufficient. We also need to watch for cleanups of the
2820 expression we are about to expand. Unfortunately, we cannot know
2821 if it has cleanups until we expand it, and we want to change how we
2822 expand it depending upon if we need cleanups. We can't win. */
2824 cleanups = any_pending_cleanups (1);
2829 if (TREE_CODE (retval) == RESULT_DECL)
2830 retval_rhs = retval;
2831 else if ((TREE_CODE (retval) == MODIFY_EXPR || TREE_CODE (retval) == INIT_EXPR)
2832 && TREE_CODE (TREE_OPERAND (retval, 0)) == RESULT_DECL)
2833 retval_rhs = TREE_OPERAND (retval, 1);
2834 else if (TREE_TYPE (retval) == void_type_node)
2835 /* Recognize tail-recursive call to void function. */
2836 retval_rhs = retval;
2838 retval_rhs = NULL_TREE;
2840 /* Only use `last_insn' if there are cleanups which must be run. */
2841 if (cleanups || cleanup_label != 0)
2842 last_insn = get_last_insn ();
2844 /* Distribute return down conditional expr if either of the sides
2845 may involve tail recursion (see test below). This enhances the number
2846 of tail recursions we see. Don't do this always since it can produce
2847 sub-optimal code in some cases and we distribute assignments into
2848 conditional expressions when it would help. */
2850 if (optimize && retval_rhs != 0
2851 && frame_offset == 0
2852 && TREE_CODE (retval_rhs) == COND_EXPR
2853 && (TREE_CODE (TREE_OPERAND (retval_rhs, 1)) == CALL_EXPR
2854 || TREE_CODE (TREE_OPERAND (retval_rhs, 2)) == CALL_EXPR))
2856 rtx label = gen_label_rtx ();
2859 do_jump (TREE_OPERAND (retval_rhs, 0), label, NULL_RTX);
2860 start_cleanup_deferral ();
2861 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
2862 DECL_RESULT (current_function_decl),
2863 TREE_OPERAND (retval_rhs, 1));
2864 TREE_SIDE_EFFECTS (expr) = 1;
2865 expand_return (expr);
2868 expr = build (MODIFY_EXPR, TREE_TYPE (TREE_TYPE (current_function_decl)),
2869 DECL_RESULT (current_function_decl),
2870 TREE_OPERAND (retval_rhs, 2));
2871 TREE_SIDE_EFFECTS (expr) = 1;
2872 expand_return (expr);
2873 end_cleanup_deferral ();
2877 /* Attempt to optimize the call if it is tail recursive. */
2878 if (flag_optimize_sibling_calls
2879 && retval_rhs != NULL_TREE
2880 && frame_offset == 0
2881 && TREE_CODE (retval_rhs) == CALL_EXPR
2882 && TREE_CODE (TREE_OPERAND (retval_rhs, 0)) == ADDR_EXPR
2883 && (TREE_OPERAND (TREE_OPERAND (retval_rhs, 0), 0)
2884 == current_function_decl)
2885 && optimize_tail_recursion (TREE_OPERAND (retval_rhs, 1), last_insn))
2889 /* This optimization is safe if there are local cleanups
2890 because expand_null_return takes care of them.
2891 ??? I think it should also be safe when there is a cleanup label,
2892 because expand_null_return takes care of them, too.
2893 Any reason why not? */
2894 if (HAVE_return && cleanup_label == 0
2895 && ! current_function_returns_pcc_struct
2896 && BRANCH_COST <= 1)
2898 /* If this is return x == y; then generate
2899 if (x == y) return 1; else return 0;
2900 if we can do it with explicit return insns and branches are cheap,
2901 but not if we have the corresponding scc insn. */
2904 switch (TREE_CODE (retval_rhs))
2930 case TRUTH_ANDIF_EXPR:
2931 case TRUTH_ORIF_EXPR:
2932 case TRUTH_AND_EXPR:
2934 case TRUTH_NOT_EXPR:
2935 case TRUTH_XOR_EXPR:
2938 op0 = gen_label_rtx ();
2939 jumpifnot (retval_rhs, op0);
2940 expand_value_return (const1_rtx);
2942 expand_value_return (const0_rtx);
2951 #endif /* HAVE_return */
2953 /* If the result is an aggregate that is being returned in one (or more)
2954 registers, load the registers here. The compiler currently can't handle
2955 copying a BLKmode value into registers. We could put this code in a
2956 more general area (for use by everyone instead of just function
2957 call/return), but until this feature is generally usable it is kept here
2958 (and in expand_call). The value must go into a pseudo in case there
2959 are cleanups that will clobber the real return register. */
2962 && TYPE_MODE (TREE_TYPE (retval_rhs)) == BLKmode
2963 && GET_CODE (result_rtl) == REG)
2966 unsigned HOST_WIDE_INT bitpos, xbitpos;
2967 unsigned HOST_WIDE_INT big_endian_correction = 0;
2968 unsigned HOST_WIDE_INT bytes
2969 = int_size_in_bytes (TREE_TYPE (retval_rhs));
2970 int n_regs = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;
2971 unsigned int bitsize
2972 = MIN (TYPE_ALIGN (TREE_TYPE (retval_rhs)), BITS_PER_WORD);
2973 rtx *result_pseudos = (rtx *) alloca (sizeof (rtx) * n_regs);
2974 rtx result_reg, src = NULL_RTX, dst = NULL_RTX;
2975 rtx result_val = expand_expr (retval_rhs, NULL_RTX, VOIDmode, 0);
2976 enum machine_mode tmpmode, result_reg_mode;
2978 /* Structures whose size is not a multiple of a word are aligned
2979 to the least significant byte (to the right). On a BYTES_BIG_ENDIAN
2980 machine, this means we must skip the empty high order bytes when
2981 calculating the bit offset. */
2982 if (BYTES_BIG_ENDIAN && bytes % UNITS_PER_WORD)
2983 big_endian_correction = (BITS_PER_WORD - ((bytes % UNITS_PER_WORD)
2986 /* Copy the structure BITSIZE bits at a time. */
2987 for (bitpos = 0, xbitpos = big_endian_correction;
2988 bitpos < bytes * BITS_PER_UNIT;
2989 bitpos += bitsize, xbitpos += bitsize)
2991 /* We need a new destination pseudo each time xbitpos is
2992 on a word boundary and when xbitpos == big_endian_correction
2993 (the first time through). */
2994 if (xbitpos % BITS_PER_WORD == 0
2995 || xbitpos == big_endian_correction)
2997 /* Generate an appropriate register. */
2998 dst = gen_reg_rtx (word_mode);
2999 result_pseudos[xbitpos / BITS_PER_WORD] = dst;
3001 /* Clobber the destination before we move anything into it. */
3002 emit_insn (gen_rtx_CLOBBER (VOIDmode, dst));
3005 /* We need a new source operand each time bitpos is on a word
3007 if (bitpos % BITS_PER_WORD == 0)
3008 src = operand_subword_force (result_val,
3009 bitpos / BITS_PER_WORD,
3012 /* Use bitpos for the source extraction (left justified) and
3013 xbitpos for the destination store (right justified). */
3014 store_bit_field (dst, bitsize, xbitpos % BITS_PER_WORD, word_mode,
3015 extract_bit_field (src, bitsize,
3016 bitpos % BITS_PER_WORD, 1,
3017 NULL_RTX, word_mode, word_mode,
3018 bitsize, BITS_PER_WORD),
3019 bitsize, BITS_PER_WORD);
3022 /* Find the smallest integer mode large enough to hold the
3023 entire structure and use that mode instead of BLKmode
3024 on the USE insn for the return register. */
3025 bytes = int_size_in_bytes (TREE_TYPE (retval_rhs));
3026 for (tmpmode = GET_CLASS_NARROWEST_MODE (MODE_INT);
3027 tmpmode != VOIDmode;
3028 tmpmode = GET_MODE_WIDER_MODE (tmpmode))
3030 /* Have we found a large enough mode? */
3031 if (GET_MODE_SIZE (tmpmode) >= bytes)
3035 /* No suitable mode found. */
3036 if (tmpmode == VOIDmode)
3039 PUT_MODE (result_rtl, tmpmode);
3041 if (GET_MODE_SIZE (tmpmode) < GET_MODE_SIZE (word_mode))
3042 result_reg_mode = word_mode;
3044 result_reg_mode = tmpmode;
3045 result_reg = gen_reg_rtx (result_reg_mode);
3048 for (i = 0; i < n_regs; i++)
3049 emit_move_insn (operand_subword (result_reg, i, 0, result_reg_mode),
3052 if (tmpmode != result_reg_mode)
3053 result_reg = gen_lowpart (tmpmode, result_reg);
3055 expand_value_return (result_reg);
3059 && TREE_TYPE (retval_rhs) != void_type_node
3060 && (GET_CODE (result_rtl) == REG
3061 || (GET_CODE (result_rtl) == PARALLEL)))
3063 /* Calculate the return value into a temporary (usually a pseudo
3065 val = assign_temp (TREE_TYPE (DECL_RESULT (current_function_decl)),
3067 val = expand_expr (retval_rhs, val, GET_MODE (val), 0);
3068 val = force_not_mem (val);
3070 /* Return the calculated value, doing cleanups first. */
3071 expand_value_return (val);
3075 /* No cleanups or no hard reg used;
3076 calculate value into hard return reg. */
3077 expand_expr (retval, const0_rtx, VOIDmode, 0);
3079 expand_value_return (result_rtl);
3083 /* Return 1 if the end of the generated RTX is not a barrier.
3084 This means code already compiled can drop through. */
3087 drop_through_at_end_p ()
3089 rtx insn = get_last_insn ();
3090 while (insn && GET_CODE (insn) == NOTE)
3091 insn = PREV_INSN (insn);
3092 return insn && GET_CODE (insn) != BARRIER;
3095 /* Attempt to optimize a potential tail recursion call into a goto.
3096 ARGUMENTS are the arguments to a CALL_EXPR; LAST_INSN indicates
3097 where to place the jump to the tail recursion label.
3099 Return TRUE if the call was optimized into a goto. */
3102 optimize_tail_recursion (arguments, last_insn)
3106 /* Finish checking validity, and if valid emit code to set the
3107 argument variables for the new call. */
3108 if (tail_recursion_args (arguments, DECL_ARGUMENTS (current_function_decl)))
3110 if (tail_recursion_label == 0)
3112 tail_recursion_label = gen_label_rtx ();
3113 emit_label_after (tail_recursion_label,
3114 tail_recursion_reentry);
3117 expand_goto_internal (NULL_TREE, tail_recursion_label, last_insn);
3124 /* Emit code to alter this function's formal parms for a tail-recursive call.
3125 ACTUALS is a list of actual parameter expressions (chain of TREE_LISTs).
3126 FORMALS is the chain of decls of formals.
3127 Return 1 if this can be done;
3128 otherwise return 0 and do not emit any code. */
3131 tail_recursion_args (actuals, formals)
3132 tree actuals, formals;
3134 register tree a = actuals, f = formals;
3136 register rtx *argvec;
3138 /* Check that number and types of actuals are compatible
3139 with the formals. This is not always true in valid C code.
3140 Also check that no formal needs to be addressable
3141 and that all formals are scalars. */
3143 /* Also count the args. */
3145 for (a = actuals, f = formals, i = 0; a && f; a = TREE_CHAIN (a), f = TREE_CHAIN (f), i++)
3147 if (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_VALUE (a)))
3148 != TYPE_MAIN_VARIANT (TREE_TYPE (f)))
3150 if (GET_CODE (DECL_RTL (f)) != REG || DECL_MODE (f) == BLKmode)
3153 if (a != 0 || f != 0)
3156 /* Compute all the actuals. */
3158 argvec = (rtx *) alloca (i * sizeof (rtx));
3160 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3161 argvec[i] = expand_expr (TREE_VALUE (a), NULL_RTX, VOIDmode, 0);
3163 /* Find which actual values refer to current values of previous formals.
3164 Copy each of them now, before any formal is changed. */
3166 for (a = actuals, i = 0; a; a = TREE_CHAIN (a), i++)
3170 for (f = formals, j = 0; j < i; f = TREE_CHAIN (f), j++)
3171 if (reg_mentioned_p (DECL_RTL (f), argvec[i]))
3172 { copy = 1; break; }
3174 argvec[i] = copy_to_reg (argvec[i]);
3177 /* Store the values of the actuals into the formals. */
3179 for (f = formals, a = actuals, i = 0; f;
3180 f = TREE_CHAIN (f), a = TREE_CHAIN (a), i++)
3182 if (GET_MODE (DECL_RTL (f)) == GET_MODE (argvec[i]))
3183 emit_move_insn (DECL_RTL (f), argvec[i]);
3185 convert_move (DECL_RTL (f), argvec[i],
3186 TREE_UNSIGNED (TREE_TYPE (TREE_VALUE (a))));
3193 /* Generate the RTL code for entering a binding contour.
3194 The variables are declared one by one, by calls to `expand_decl'.
3196 FLAGS is a bitwise or of the following flags:
3198 1 - Nonzero if this construct should be visible to
3201 2 - Nonzero if this contour does not require a
3202 NOTE_INSN_BLOCK_BEG note. Virtually all calls from
3203 language-independent code should set this flag because they
3204 will not create corresponding BLOCK nodes. (There should be
3205 a one-to-one correspondence between NOTE_INSN_BLOCK_BEG notes
3206 and BLOCKs.) If this flag is set, MARK_ENDS should be zero
3207 when expand_end_bindings is called.
3209 If we are creating a NOTE_INSN_BLOCK_BEG note, a BLOCK may
3210 optionally be supplied. If so, it becomes the NOTE_BLOCK for the
3214 expand_start_bindings_and_block (flags, block)
3218 struct nesting *thisblock = ALLOC_NESTING ();
3220 int exit_flag = ((flags & 1) != 0);
3221 int block_flag = ((flags & 2) == 0);
3223 /* If a BLOCK is supplied, then the caller should be requesting a
3224 NOTE_INSN_BLOCK_BEG note. */
3225 if (!block_flag && block)
3228 /* Create a note to mark the beginning of the block. */
3231 note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_BEG);
3232 NOTE_BLOCK (note) = block;
3235 note = emit_note (NULL_PTR, NOTE_INSN_DELETED);
3237 /* Make an entry on block_stack for the block we are entering. */
3239 thisblock->next = block_stack;
3240 thisblock->all = nesting_stack;
3241 thisblock->depth = ++nesting_depth;
3242 thisblock->data.block.stack_level = 0;
3243 thisblock->data.block.cleanups = 0;
3244 thisblock->data.block.n_function_calls = 0;
3245 thisblock->data.block.exception_region = 0;
3246 thisblock->data.block.block_target_temp_slot_level = target_temp_slot_level;
3248 thisblock->data.block.conditional_code = 0;
3249 thisblock->data.block.last_unconditional_cleanup = note;
3250 /* When we insert instructions after the last unconditional cleanup,
3251 we don't adjust last_insn. That means that a later add_insn will
3252 clobber the instructions we've just added. The easiest way to
3253 fix this is to just insert another instruction here, so that the
3254 instructions inserted after the last unconditional cleanup are
3255 never the last instruction. */
3256 emit_note (NULL_PTR, NOTE_INSN_DELETED);
3257 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
3260 && !(block_stack->data.block.cleanups == NULL_TREE
3261 && block_stack->data.block.outer_cleanups == NULL_TREE))
3262 thisblock->data.block.outer_cleanups
3263 = tree_cons (NULL_TREE, block_stack->data.block.cleanups,
3264 block_stack->data.block.outer_cleanups);
3266 thisblock->data.block.outer_cleanups = 0;
3267 thisblock->data.block.label_chain = 0;
3268 thisblock->data.block.innermost_stack_block = stack_block_stack;
3269 thisblock->data.block.first_insn = note;
3270 thisblock->data.block.block_start_count = ++current_block_start_count;
3271 thisblock->exit_label = exit_flag ? gen_label_rtx () : 0;
3272 block_stack = thisblock;
3273 nesting_stack = thisblock;
3275 /* Make a new level for allocating stack slots. */
3279 /* Specify the scope of temporaries created by TARGET_EXPRs. Similar
3280 to CLEANUP_POINT_EXPR, but handles cases when a series of calls to
3281 expand_expr are made. After we end the region, we know that all
3282 space for all temporaries that were created by TARGET_EXPRs will be
3283 destroyed and their space freed for reuse. */
3286 expand_start_target_temps ()
3288 /* This is so that even if the result is preserved, the space
3289 allocated will be freed, as we know that it is no longer in use. */
3292 /* Start a new binding layer that will keep track of all cleanup
3293 actions to be performed. */
3294 expand_start_bindings (2);
3296 target_temp_slot_level = temp_slot_level;
3300 expand_end_target_temps ()
3302 expand_end_bindings (NULL_TREE, 0, 0);
3304 /* This is so that even if the result is preserved, the space
3305 allocated will be freed, as we know that it is no longer in use. */
3309 /* Given a pointer to a BLOCK node return non-zero if (and only if) the node
3310 in question represents the outermost pair of curly braces (i.e. the "body
3311 block") of a function or method.
3313 For any BLOCK node representing a "body block" of a function or method, the
3314 BLOCK_SUPERCONTEXT of the node will point to another BLOCK node which
3315 represents the outermost (function) scope for the function or method (i.e.
3316 the one which includes the formal parameters). The BLOCK_SUPERCONTEXT of
3317 *that* node in turn will point to the relevant FUNCTION_DECL node. */
3320 is_body_block (stmt)
3323 if (TREE_CODE (stmt) == BLOCK)
3325 tree parent = BLOCK_SUPERCONTEXT (stmt);
3327 if (parent && TREE_CODE (parent) == BLOCK)
3329 tree grandparent = BLOCK_SUPERCONTEXT (parent);
3331 if (grandparent && TREE_CODE (grandparent) == FUNCTION_DECL)
3339 /* Mark top block of block_stack as an implicit binding for an
3340 exception region. This is used to prevent infinite recursion when
3341 ending a binding with expand_end_bindings. It is only ever called
3342 by expand_eh_region_start, as that it the only way to create a
3343 block stack for a exception region. */
3346 mark_block_as_eh_region ()
3348 block_stack->data.block.exception_region = 1;
3349 if (block_stack->next
3350 && block_stack->next->data.block.conditional_code)
3352 block_stack->data.block.conditional_code
3353 = block_stack->next->data.block.conditional_code;
3354 block_stack->data.block.last_unconditional_cleanup
3355 = block_stack->next->data.block.last_unconditional_cleanup;
3356 block_stack->data.block.cleanup_ptr
3357 = block_stack->next->data.block.cleanup_ptr;
3361 /* True if we are currently emitting insns in an area of output code
3362 that is controlled by a conditional expression. This is used by
3363 the cleanup handling code to generate conditional cleanup actions. */
3366 conditional_context ()
3368 return block_stack && block_stack->data.block.conditional_code;
3371 /* Mark top block of block_stack as not for an implicit binding for an
3372 exception region. This is only ever done by expand_eh_region_end
3373 to let expand_end_bindings know that it is being called explicitly
3374 to end the binding layer for just the binding layer associated with
3375 the exception region, otherwise expand_end_bindings would try and
3376 end all implicit binding layers for exceptions regions, and then
3377 one normal binding layer. */
3380 mark_block_as_not_eh_region ()
3382 block_stack->data.block.exception_region = 0;
3385 /* True if the top block of block_stack was marked as for an exception
3386 region by mark_block_as_eh_region. */
3391 return cfun && block_stack && block_stack->data.block.exception_region;
3394 /* Emit a handler label for a nonlocal goto handler.
3395 Also emit code to store the handler label in SLOT before BEFORE_INSN. */
3398 expand_nl_handler_label (slot, before_insn)
3399 rtx slot, before_insn;
3402 rtx handler_label = gen_label_rtx ();
3404 /* Don't let jump_optimize delete the handler. */
3405 LABEL_PRESERVE_P (handler_label) = 1;
3408 emit_move_insn (slot, gen_rtx_LABEL_REF (Pmode, handler_label));
3409 insns = get_insns ();
3411 emit_insns_before (insns, before_insn);
3413 emit_label (handler_label);
3415 return handler_label;
3418 /* Emit code to restore vital registers at the beginning of a nonlocal goto
3421 expand_nl_goto_receiver ()
3423 #ifdef HAVE_nonlocal_goto
3424 if (! HAVE_nonlocal_goto)
3426 /* First adjust our frame pointer to its actual value. It was
3427 previously set to the start of the virtual area corresponding to
3428 the stacked variables when we branched here and now needs to be
3429 adjusted to the actual hardware fp value.
3431 Assignments are to virtual registers are converted by
3432 instantiate_virtual_regs into the corresponding assignment
3433 to the underlying register (fp in this case) that makes
3434 the original assignment true.
3435 So the following insn will actually be
3436 decrementing fp by STARTING_FRAME_OFFSET. */
3437 emit_move_insn (virtual_stack_vars_rtx, hard_frame_pointer_rtx);
3439 #if ARG_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM
3440 if (fixed_regs[ARG_POINTER_REGNUM])
3442 #ifdef ELIMINABLE_REGS
3443 /* If the argument pointer can be eliminated in favor of the
3444 frame pointer, we don't need to restore it. We assume here
3445 that if such an elimination is present, it can always be used.
3446 This is the case on all known machines; if we don't make this
3447 assumption, we do unnecessary saving on many machines. */
3448 static struct elims {int from, to;} elim_regs[] = ELIMINABLE_REGS;
3451 for (i = 0; i < sizeof elim_regs / sizeof elim_regs[0]; i++)
3452 if (elim_regs[i].from == ARG_POINTER_REGNUM
3453 && elim_regs[i].to == HARD_FRAME_POINTER_REGNUM)
3456 if (i == sizeof elim_regs / sizeof elim_regs [0])
3459 /* Now restore our arg pointer from the address at which it
3460 was saved in our stack frame.
3461 If there hasn't be space allocated for it yet, make
3463 if (arg_pointer_save_area == 0)
3464 arg_pointer_save_area
3465 = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
3466 emit_move_insn (virtual_incoming_args_rtx,
3467 /* We need a pseudo here, or else
3468 instantiate_virtual_regs_1 complains. */
3469 copy_to_reg (arg_pointer_save_area));
3474 #ifdef HAVE_nonlocal_goto_receiver
3475 if (HAVE_nonlocal_goto_receiver)
3476 emit_insn (gen_nonlocal_goto_receiver ());
3480 /* Make handlers for nonlocal gotos taking place in the function calls in
3484 expand_nl_goto_receivers (thisblock)
3485 struct nesting *thisblock;
3488 rtx afterward = gen_label_rtx ();
3493 /* Record the handler address in the stack slot for that purpose,
3494 during this block, saving and restoring the outer value. */
3495 if (thisblock->next != 0)
3496 for (slot = nonlocal_goto_handler_slots; slot; slot = XEXP (slot, 1))
3498 rtx save_receiver = gen_reg_rtx (Pmode);
3499 emit_move_insn (XEXP (slot, 0), save_receiver);
3502 emit_move_insn (save_receiver, XEXP (slot, 0));
3503 insns = get_insns ();
3505 emit_insns_before (insns, thisblock->data.block.first_insn);
3508 /* Jump around the handlers; they run only when specially invoked. */
3509 emit_jump (afterward);
3511 /* Make a separate handler for each label. */
3512 link = nonlocal_labels;
3513 slot = nonlocal_goto_handler_slots;
3514 label_list = NULL_RTX;
3515 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3516 /* Skip any labels we shouldn't be able to jump to from here,
3517 we generate one special handler for all of them below which just calls
3519 if (! DECL_TOO_LATE (TREE_VALUE (link)))
3522 lab = expand_nl_handler_label (XEXP (slot, 0),
3523 thisblock->data.block.first_insn);
3524 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3526 expand_nl_goto_receiver ();
3528 /* Jump to the "real" nonlocal label. */
3529 expand_goto (TREE_VALUE (link));
3532 /* A second pass over all nonlocal labels; this time we handle those
3533 we should not be able to jump to at this point. */
3534 link = nonlocal_labels;
3535 slot = nonlocal_goto_handler_slots;
3537 for (; link; link = TREE_CHAIN (link), slot = XEXP (slot, 1))
3538 if (DECL_TOO_LATE (TREE_VALUE (link)))
3541 lab = expand_nl_handler_label (XEXP (slot, 0),
3542 thisblock->data.block.first_insn);
3543 label_list = gen_rtx_EXPR_LIST (VOIDmode, lab, label_list);
3549 expand_nl_goto_receiver ();
3550 emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "abort"), 0,
3555 nonlocal_goto_handler_labels = label_list;
3556 emit_label (afterward);
3559 /* Warn about any unused VARS (which may contain nodes other than
3560 VAR_DECLs, but such nodes are ignored). The nodes are connected
3561 via the TREE_CHAIN field. */
3564 warn_about_unused_variables (vars)
3570 for (decl = vars; decl; decl = TREE_CHAIN (decl))
3571 if (TREE_CODE (decl) == VAR_DECL
3572 && ! TREE_USED (decl)
3573 && ! DECL_IN_SYSTEM_HEADER (decl)
3574 && DECL_NAME (decl) && ! DECL_ARTIFICIAL (decl))
3575 warning_with_decl (decl, "unused variable `%s'");
3578 /* Generate RTL code to terminate a binding contour.
3580 VARS is the chain of VAR_DECL nodes for the variables bound in this
3581 contour. There may actually be other nodes in this chain, but any
3582 nodes other than VAR_DECLS are ignored.
3584 MARK_ENDS is nonzero if we should put a note at the beginning
3585 and end of this binding contour.
3587 DONT_JUMP_IN is nonzero if it is not valid to jump into this contour.
3588 (That is true automatically if the contour has a saved stack level.) */
3591 expand_end_bindings (vars, mark_ends, dont_jump_in)
3596 register struct nesting *thisblock;
3598 while (block_stack->data.block.exception_region)
3600 /* Because we don't need or want a new temporary level and
3601 because we didn't create one in expand_eh_region_start,
3602 create a fake one now to avoid removing one in
3603 expand_end_bindings. */
3606 block_stack->data.block.exception_region = 0;
3608 expand_end_bindings (NULL_TREE, 0, 0);
3611 /* Since expand_eh_region_start does an expand_start_bindings, we
3612 have to first end all the bindings that were created by
3613 expand_eh_region_start. */
3615 thisblock = block_stack;
3617 /* If any of the variables in this scope were not used, warn the
3619 warn_about_unused_variables (vars);
3621 if (thisblock->exit_label)
3623 do_pending_stack_adjust ();
3624 emit_label (thisblock->exit_label);
3627 /* If necessary, make handlers for nonlocal gotos taking
3628 place in the function calls in this block. */
3629 if (function_call_count != thisblock->data.block.n_function_calls
3631 /* Make handler for outermost block
3632 if there were any nonlocal gotos to this function. */
3633 && (thisblock->next == 0 ? current_function_has_nonlocal_label
3634 /* Make handler for inner block if it has something
3635 special to do when you jump out of it. */
3636 : (thisblock->data.block.cleanups != 0
3637 || thisblock->data.block.stack_level != 0)))
3638 expand_nl_goto_receivers (thisblock);
3640 /* Don't allow jumping into a block that has a stack level.
3641 Cleanups are allowed, though. */
3643 || thisblock->data.block.stack_level != 0)
3645 struct label_chain *chain;
3647 /* Any labels in this block are no longer valid to go to.
3648 Mark them to cause an error message. */
3649 for (chain = thisblock->data.block.label_chain; chain; chain = chain->next)
3651 DECL_TOO_LATE (chain->label) = 1;
3652 /* If any goto without a fixup came to this label,
3653 that must be an error, because gotos without fixups
3654 come from outside all saved stack-levels. */
3655 if (TREE_ADDRESSABLE (chain->label))
3656 error_with_decl (chain->label,
3657 "label `%s' used before containing binding contour");
3661 /* Restore stack level in effect before the block
3662 (only if variable-size objects allocated). */
3663 /* Perform any cleanups associated with the block. */
3665 if (thisblock->data.block.stack_level != 0
3666 || thisblock->data.block.cleanups != 0)
3668 /* Only clean up here if this point can actually be reached. */
3669 int reachable = GET_CODE (get_last_insn ()) != BARRIER;
3671 /* Don't let cleanups affect ({...}) constructs. */
3672 int old_expr_stmts_for_value = expr_stmts_for_value;
3673 rtx old_last_expr_value = last_expr_value;
3674 tree old_last_expr_type = last_expr_type;
3675 expr_stmts_for_value = 0;
3677 /* Do the cleanups. */
3678 expand_cleanups (thisblock->data.block.cleanups, NULL_TREE, 0, reachable);
3680 do_pending_stack_adjust ();
3682 expr_stmts_for_value = old_expr_stmts_for_value;
3683 last_expr_value = old_last_expr_value;
3684 last_expr_type = old_last_expr_type;
3686 /* Restore the stack level. */
3688 if (reachable && thisblock->data.block.stack_level != 0)
3690 emit_stack_restore (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3691 thisblock->data.block.stack_level, NULL_RTX);
3692 if (nonlocal_goto_handler_slots != 0)
3693 emit_stack_save (SAVE_NONLOCAL, &nonlocal_goto_stack_level,
3697 /* Any gotos out of this block must also do these things.
3698 Also report any gotos with fixups that came to labels in this
3700 fixup_gotos (thisblock,
3701 thisblock->data.block.stack_level,
3702 thisblock->data.block.cleanups,
3703 thisblock->data.block.first_insn,
3707 /* Mark the beginning and end of the scope if requested.
3708 We do this now, after running cleanups on the variables
3709 just going out of scope, so they are in scope for their cleanups. */
3713 rtx note = emit_note (NULL_PTR, NOTE_INSN_BLOCK_END);
3714 NOTE_BLOCK (note) = NOTE_BLOCK (thisblock->data.block.first_insn);
3717 /* Get rid of the beginning-mark if we don't make an end-mark. */
3718 NOTE_LINE_NUMBER (thisblock->data.block.first_insn) = NOTE_INSN_DELETED;
3720 /* Restore the temporary level of TARGET_EXPRs. */
3721 target_temp_slot_level = thisblock->data.block.block_target_temp_slot_level;
3723 /* Restore block_stack level for containing block. */
3725 stack_block_stack = thisblock->data.block.innermost_stack_block;
3726 POPSTACK (block_stack);
3728 /* Pop the stack slot nesting and free any slots at this level. */
3732 /* Generate RTL for the automatic variable declaration DECL.
3733 (Other kinds of declarations are simply ignored if seen here.) */
3739 struct nesting *thisblock;
3742 type = TREE_TYPE (decl);
3744 /* Only automatic variables need any expansion done.
3745 Static and external variables, and external functions,
3746 will be handled by `assemble_variable' (called from finish_decl).
3747 TYPE_DECL and CONST_DECL require nothing.
3748 PARM_DECLs are handled in `assign_parms'. */
3750 if (TREE_CODE (decl) != VAR_DECL)
3752 if (TREE_STATIC (decl) || DECL_EXTERNAL (decl))
3755 thisblock = block_stack;
3757 /* Create the RTL representation for the variable. */
3759 if (type == error_mark_node)
3760 DECL_RTL (decl) = gen_rtx_MEM (BLKmode, const0_rtx);
3761 else if (DECL_SIZE (decl) == 0)
3762 /* Variable with incomplete type. */
3764 if (DECL_INITIAL (decl) == 0)
3765 /* Error message was already done; now avoid a crash. */
3766 DECL_RTL (decl) = assign_stack_temp (DECL_MODE (decl), 0, 1);
3768 /* An initializer is going to decide the size of this array.
3769 Until we know the size, represent its address with a reg. */
3770 DECL_RTL (decl) = gen_rtx_MEM (BLKmode, gen_reg_rtx (Pmode));
3771 MEM_SET_IN_STRUCT_P (DECL_RTL (decl), AGGREGATE_TYPE_P (type));
3773 else if (DECL_MODE (decl) != BLKmode
3774 /* If -ffloat-store, don't put explicit float vars
3776 && !(flag_float_store
3777 && TREE_CODE (type) == REAL_TYPE)
3778 && ! TREE_THIS_VOLATILE (decl)
3779 && ! TREE_ADDRESSABLE (decl)
3780 && (DECL_REGISTER (decl) || optimize)
3781 /* if -fcheck-memory-usage, check all variables. */
3782 && ! current_function_check_memory_usage)
3784 /* Automatic variable that can go in a register. */
3785 int unsignedp = TREE_UNSIGNED (type);
3786 enum machine_mode reg_mode
3787 = promote_mode (type, DECL_MODE (decl), &unsignedp, 0);
3789 DECL_RTL (decl) = gen_reg_rtx (reg_mode);
3790 mark_user_reg (DECL_RTL (decl));
3792 if (POINTER_TYPE_P (type))
3793 mark_reg_pointer (DECL_RTL (decl),
3794 TYPE_ALIGN (TREE_TYPE (TREE_TYPE (decl))));
3798 else if (TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST
3799 && ! (flag_stack_check && ! STACK_CHECK_BUILTIN
3800 && 0 < compare_tree_int (DECL_SIZE_UNIT (decl),
3801 STACK_CHECK_MAX_VAR_SIZE)))
3803 /* Variable of fixed size that goes on the stack. */
3807 /* If we previously made RTL for this decl, it must be an array
3808 whose size was determined by the initializer.
3809 The old address was a register; set that register now
3810 to the proper address. */
3811 if (DECL_RTL (decl) != 0)
3813 if (GET_CODE (DECL_RTL (decl)) != MEM
3814 || GET_CODE (XEXP (DECL_RTL (decl), 0)) != REG)
3816 oldaddr = XEXP (DECL_RTL (decl), 0);
3819 DECL_RTL (decl) = assign_temp (TREE_TYPE (decl), 1, 1, 1);
3820 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3821 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3823 /* Set alignment we actually gave this decl. */
3824 DECL_ALIGN (decl) = (DECL_MODE (decl) == BLKmode ? BIGGEST_ALIGNMENT
3825 : GET_MODE_BITSIZE (DECL_MODE (decl)));
3829 addr = force_operand (XEXP (DECL_RTL (decl), 0), oldaddr);
3830 if (addr != oldaddr)
3831 emit_move_insn (oldaddr, addr);
3834 /* If this is a memory ref that contains aggregate components,
3835 mark it as such for cse and loop optimize. */
3836 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3837 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3839 /* If this is in memory because of -ffloat-store,
3840 set the volatile bit, to prevent optimizations from
3841 undoing the effects. */
3842 if (flag_float_store && TREE_CODE (type) == REAL_TYPE)
3843 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3846 MEM_ALIAS_SET (DECL_RTL (decl)) = get_alias_set (decl);
3849 /* Dynamic-size object: must push space on the stack. */
3853 /* Record the stack pointer on entry to block, if have
3854 not already done so. */
3855 if (thisblock->data.block.stack_level == 0)
3857 do_pending_stack_adjust ();
3858 emit_stack_save (thisblock->next ? SAVE_BLOCK : SAVE_FUNCTION,
3859 &thisblock->data.block.stack_level,
3860 thisblock->data.block.first_insn);
3861 stack_block_stack = thisblock;
3864 /* In function-at-a-time mode, variable_size doesn't expand this,
3866 if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type))
3867 expand_expr (TYPE_MAX_VALUE (TYPE_DOMAIN (type)),
3868 const0_rtx, VOIDmode, 0);
3870 /* Compute the variable's size, in bytes. */
3871 size = expand_expr (DECL_SIZE_UNIT (decl), NULL_RTX, VOIDmode, 0);
3874 /* Allocate space on the stack for the variable. Note that
3875 DECL_ALIGN says how the variable is to be aligned and we
3876 cannot use it to conclude anything about the alignment of
3878 address = allocate_dynamic_stack_space (size, NULL_RTX,
3879 TYPE_ALIGN (TREE_TYPE (decl)));
3881 /* Reference the variable indirect through that rtx. */
3882 DECL_RTL (decl) = gen_rtx_MEM (DECL_MODE (decl), address);
3884 /* If this is a memory ref that contains aggregate components,
3885 mark it as such for cse and loop optimize. */
3886 MEM_SET_IN_STRUCT_P (DECL_RTL (decl),
3887 AGGREGATE_TYPE_P (TREE_TYPE (decl)));
3889 /* Indicate the alignment we actually gave this variable. */
3890 #ifdef STACK_BOUNDARY
3891 DECL_ALIGN (decl) = STACK_BOUNDARY;
3893 DECL_ALIGN (decl) = BIGGEST_ALIGNMENT;
3897 if (TREE_THIS_VOLATILE (decl))
3898 MEM_VOLATILE_P (DECL_RTL (decl)) = 1;
3900 if (TREE_READONLY (decl))
3901 RTX_UNCHANGING_P (DECL_RTL (decl)) = 1;
3904 /* Emit code to perform the initialization of a declaration DECL. */
3907 expand_decl_init (decl)
3910 int was_used = TREE_USED (decl);
3912 /* If this is a CONST_DECL, we don't have to generate any code, but
3913 if DECL_INITIAL is a constant, call expand_expr to force TREE_CST_RTL
3914 to be set while in the obstack containing the constant. If we don't
3915 do this, we can lose if we have functions nested three deep and the middle
3916 function makes a CONST_DECL whose DECL_INITIAL is a STRING_CST while
3917 the innermost function is the first to expand that STRING_CST. */
3918 if (TREE_CODE (decl) == CONST_DECL)
3920 if (DECL_INITIAL (decl) && TREE_CONSTANT (DECL_INITIAL (decl)))
3921 expand_expr (DECL_INITIAL (decl), NULL_RTX, VOIDmode,
3922 EXPAND_INITIALIZER);
3926 if (TREE_STATIC (decl))
3929 /* Compute and store the initial value now. */
3931 if (DECL_INITIAL (decl) == error_mark_node)
3933 enum tree_code code = TREE_CODE (TREE_TYPE (decl));
3935 if (code == INTEGER_TYPE || code == REAL_TYPE || code == ENUMERAL_TYPE
3936 || code == POINTER_TYPE || code == REFERENCE_TYPE)
3937 expand_assignment (decl, convert (TREE_TYPE (decl), integer_zero_node),
3941 else if (DECL_INITIAL (decl) && TREE_CODE (DECL_INITIAL (decl)) != TREE_LIST)
3943 emit_line_note (DECL_SOURCE_FILE (decl), DECL_SOURCE_LINE (decl));
3944 expand_assignment (decl, DECL_INITIAL (decl), 0, 0);
3948 /* Don't let the initialization count as "using" the variable. */
3949 TREE_USED (decl) = was_used;
3951 /* Free any temporaries we made while initializing the decl. */
3952 preserve_temp_slots (NULL_RTX);
3956 /* CLEANUP is an expression to be executed at exit from this binding contour;
3957 for example, in C++, it might call the destructor for this variable.
3959 We wrap CLEANUP in an UNSAVE_EXPR node, so that we can expand the
3960 CLEANUP multiple times, and have the correct semantics. This
3961 happens in exception handling, for gotos, returns, breaks that
3962 leave the current scope.
3964 If CLEANUP is nonzero and DECL is zero, we record a cleanup
3965 that is not associated with any particular variable. */
3968 expand_decl_cleanup (decl, cleanup)
3971 struct nesting *thisblock;
3973 /* Error if we are not in any block. */
3974 if (cfun == 0 || block_stack == 0)
3977 thisblock = block_stack;
3979 /* Record the cleanup if there is one. */
3985 tree *cleanups = &thisblock->data.block.cleanups;
3986 int cond_context = conditional_context ();
3990 rtx flag = gen_reg_rtx (word_mode);
3995 emit_move_insn (flag, const0_rtx);
3996 set_flag_0 = get_insns ();
3999 thisblock->data.block.last_unconditional_cleanup
4000 = emit_insns_after (set_flag_0,
4001 thisblock->data.block.last_unconditional_cleanup);
4003 emit_move_insn (flag, const1_rtx);
4005 /* All cleanups must be on the function_obstack. */
4006 push_obstacks_nochange ();
4007 resume_temporary_allocation ();
4009 cond = build_decl (VAR_DECL, NULL_TREE, type_for_mode (word_mode, 1));
4010 DECL_RTL (cond) = flag;
4012 /* Conditionalize the cleanup. */
4013 cleanup = build (COND_EXPR, void_type_node,
4014 truthvalue_conversion (cond),
4015 cleanup, integer_zero_node);
4016 cleanup = fold (cleanup);
4020 cleanups = thisblock->data.block.cleanup_ptr;
4023 /* All cleanups must be on the function_obstack. */
4024 push_obstacks_nochange ();
4025 resume_temporary_allocation ();
4026 cleanup = unsave_expr (cleanup);
4029 t = *cleanups = temp_tree_cons (decl, cleanup, *cleanups);
4032 /* If this block has a cleanup, it belongs in stack_block_stack. */
4033 stack_block_stack = thisblock;
4040 /* If this was optimized so that there is no exception region for the
4041 cleanup, then mark the TREE_LIST node, so that we can later tell
4042 if we need to call expand_eh_region_end. */
4043 if (! using_eh_for_cleanups_p
4044 || expand_eh_region_start_tree (decl, cleanup))
4045 TREE_ADDRESSABLE (t) = 1;
4046 /* If that started a new EH region, we're in a new block. */
4047 thisblock = block_stack;
4054 thisblock->data.block.last_unconditional_cleanup
4055 = emit_insns_after (seq,
4056 thisblock->data.block.last_unconditional_cleanup);
4060 thisblock->data.block.last_unconditional_cleanup
4062 thisblock->data.block.cleanup_ptr = &thisblock->data.block.cleanups;
4068 /* Like expand_decl_cleanup, but suppress generating an exception handler
4069 to perform the cleanup. */
4073 expand_decl_cleanup_no_eh (decl, cleanup)
4076 int save_eh = using_eh_for_cleanups_p;
4079 using_eh_for_cleanups_p = 0;
4080 result = expand_decl_cleanup (decl, cleanup);
4081 using_eh_for_cleanups_p = save_eh;
4087 /* Arrange for the top element of the dynamic cleanup chain to be
4088 popped if we exit the current binding contour. DECL is the
4089 associated declaration, if any, otherwise NULL_TREE. If the
4090 current contour is left via an exception, then __sjthrow will pop
4091 the top element off the dynamic cleanup chain. The code that
4092 avoids doing the action we push into the cleanup chain in the
4093 exceptional case is contained in expand_cleanups.
4095 This routine is only used by expand_eh_region_start, and that is
4096 the only way in which an exception region should be started. This
4097 routine is only used when using the setjmp/longjmp codegen method
4098 for exception handling. */
4101 expand_dcc_cleanup (decl)
4104 struct nesting *thisblock;
4107 /* Error if we are not in any block. */
4108 if (cfun == 0 || block_stack == 0)
4110 thisblock = block_stack;
4112 /* Record the cleanup for the dynamic handler chain. */
4114 /* All cleanups must be on the function_obstack. */
4115 push_obstacks_nochange ();
4116 resume_temporary_allocation ();
4117 cleanup = make_node (POPDCC_EXPR);
4120 /* Add the cleanup in a manner similar to expand_decl_cleanup. */
4121 thisblock->data.block.cleanups
4122 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
4124 /* If this block has a cleanup, it belongs in stack_block_stack. */
4125 stack_block_stack = thisblock;
4129 /* Arrange for the top element of the dynamic handler chain to be
4130 popped if we exit the current binding contour. DECL is the
4131 associated declaration, if any, otherwise NULL_TREE. If the current
4132 contour is left via an exception, then __sjthrow will pop the top
4133 element off the dynamic handler chain. The code that avoids doing
4134 the action we push into the handler chain in the exceptional case
4135 is contained in expand_cleanups.
4137 This routine is only used by expand_eh_region_start, and that is
4138 the only way in which an exception region should be started. This
4139 routine is only used when using the setjmp/longjmp codegen method
4140 for exception handling. */
4143 expand_dhc_cleanup (decl)
4146 struct nesting *thisblock;
4149 /* Error if we are not in any block. */
4150 if (cfun == 0 || block_stack == 0)
4152 thisblock = block_stack;
4154 /* Record the cleanup for the dynamic handler chain. */
4156 /* All cleanups must be on the function_obstack. */
4157 push_obstacks_nochange ();
4158 resume_temporary_allocation ();
4159 cleanup = make_node (POPDHC_EXPR);
4162 /* Add the cleanup in a manner similar to expand_decl_cleanup. */
4163 thisblock->data.block.cleanups
4164 = temp_tree_cons (decl, cleanup, thisblock->data.block.cleanups);
4166 /* If this block has a cleanup, it belongs in stack_block_stack. */
4167 stack_block_stack = thisblock;
4171 /* DECL is an anonymous union. CLEANUP is a cleanup for DECL.
4172 DECL_ELTS is the list of elements that belong to DECL's type.
4173 In each, the TREE_VALUE is a VAR_DECL, and the TREE_PURPOSE a cleanup. */
4176 expand_anon_union_decl (decl, cleanup, decl_elts)
4177 tree decl, cleanup, decl_elts;
4179 struct nesting *thisblock = cfun == 0 ? 0 : block_stack;
4183 /* If any of the elements are addressable, so is the entire union. */
4184 for (t = decl_elts; t; t = TREE_CHAIN (t))
4185 if (TREE_ADDRESSABLE (TREE_VALUE (t)))
4187 TREE_ADDRESSABLE (decl) = 1;
4192 expand_decl_cleanup (decl, cleanup);
4193 x = DECL_RTL (decl);
4195 /* Go through the elements, assigning RTL to each. */
4196 for (t = decl_elts; t; t = TREE_CHAIN (t))
4198 tree decl_elt = TREE_VALUE (t);
4199 tree cleanup_elt = TREE_PURPOSE (t);
4200 enum machine_mode mode = TYPE_MODE (TREE_TYPE (decl_elt));
4202 /* Propagate the union's alignment to the elements. */
4203 DECL_ALIGN (decl_elt) = DECL_ALIGN (decl);
4205 /* If the element has BLKmode and the union doesn't, the union is
4206 aligned such that the element doesn't need to have BLKmode, so
4207 change the element's mode to the appropriate one for its size. */
4208 if (mode == BLKmode && DECL_MODE (decl) != BLKmode)
4209 DECL_MODE (decl_elt) = mode
4210 = mode_for_size_tree (DECL_SIZE (decl_elt), MODE_INT, 1);
4212 /* (SUBREG (MEM ...)) at RTL generation time is invalid, so we
4213 instead create a new MEM rtx with the proper mode. */
4214 if (GET_CODE (x) == MEM)
4216 if (mode == GET_MODE (x))
4217 DECL_RTL (decl_elt) = x;
4220 DECL_RTL (decl_elt) = gen_rtx_MEM (mode, copy_rtx (XEXP (x, 0)));
4221 MEM_COPY_ATTRIBUTES (DECL_RTL (decl_elt), x);
4222 RTX_UNCHANGING_P (DECL_RTL (decl_elt)) = RTX_UNCHANGING_P (x);
4225 else if (GET_CODE (x) == REG)
4227 if (mode == GET_MODE (x))
4228 DECL_RTL (decl_elt) = x;
4230 DECL_RTL (decl_elt) = gen_rtx_SUBREG (mode, x, 0);
4235 /* Record the cleanup if there is one. */
4238 thisblock->data.block.cleanups
4239 = temp_tree_cons (decl_elt, cleanup_elt,
4240 thisblock->data.block.cleanups);
4244 /* Expand a list of cleanups LIST.
4245 Elements may be expressions or may be nested lists.
4247 If DONT_DO is nonnull, then any list-element
4248 whose TREE_PURPOSE matches DONT_DO is omitted.
4249 This is sometimes used to avoid a cleanup associated with
4250 a value that is being returned out of the scope.
4252 If IN_FIXUP is non-zero, we are generating this cleanup for a fixup
4253 goto and handle protection regions specially in that case.
4255 If REACHABLE, we emit code, otherwise just inform the exception handling
4256 code about this finalization. */
4259 expand_cleanups (list, dont_do, in_fixup, reachable)
4266 for (tail = list; tail; tail = TREE_CHAIN (tail))
4267 if (dont_do == 0 || TREE_PURPOSE (tail) != dont_do)
4269 if (TREE_CODE (TREE_VALUE (tail)) == TREE_LIST)
4270 expand_cleanups (TREE_VALUE (tail), dont_do, in_fixup, reachable);
4275 tree cleanup = TREE_VALUE (tail);
4277 /* See expand_d{h,c}c_cleanup for why we avoid this. */
4278 if (TREE_CODE (cleanup) != POPDHC_EXPR
4279 && TREE_CODE (cleanup) != POPDCC_EXPR
4280 /* See expand_eh_region_start_tree for this case. */
4281 && ! TREE_ADDRESSABLE (tail))
4283 cleanup = protect_with_terminate (cleanup);
4284 expand_eh_region_end (cleanup);
4290 /* Cleanups may be run multiple times. For example,
4291 when exiting a binding contour, we expand the
4292 cleanups associated with that contour. When a goto
4293 within that binding contour has a target outside that
4294 contour, it will expand all cleanups from its scope to
4295 the target. Though the cleanups are expanded multiple
4296 times, the control paths are non-overlapping so the
4297 cleanups will not be executed twice. */
4299 /* We may need to protect fixups with rethrow regions. */
4300 int protect = (in_fixup && ! TREE_ADDRESSABLE (tail));
4303 expand_fixup_region_start ();
4305 /* The cleanup might contain try-blocks, so we have to
4306 preserve our current queue. */
4308 expand_expr (TREE_VALUE (tail), const0_rtx, VOIDmode, 0);
4311 expand_fixup_region_end (TREE_VALUE (tail));
4318 /* Mark when the context we are emitting RTL for as a conditional
4319 context, so that any cleanup actions we register with
4320 expand_decl_init will be properly conditionalized when those
4321 cleanup actions are later performed. Must be called before any
4322 expression (tree) is expanded that is within a conditional context. */
4325 start_cleanup_deferral ()
4327 /* block_stack can be NULL if we are inside the parameter list. It is
4328 OK to do nothing, because cleanups aren't possible here. */
4330 ++block_stack->data.block.conditional_code;
4333 /* Mark the end of a conditional region of code. Because cleanup
4334 deferrals may be nested, we may still be in a conditional region
4335 after we end the currently deferred cleanups, only after we end all
4336 deferred cleanups, are we back in unconditional code. */
4339 end_cleanup_deferral ()
4341 /* block_stack can be NULL if we are inside the parameter list. It is
4342 OK to do nothing, because cleanups aren't possible here. */
4344 --block_stack->data.block.conditional_code;
4347 /* Move all cleanups from the current block_stack
4348 to the containing block_stack, where they are assumed to
4349 have been created. If anything can cause a temporary to
4350 be created, but not expanded for more than one level of
4351 block_stacks, then this code will have to change. */
4356 struct nesting *block = block_stack;
4357 struct nesting *outer = block->next;
4359 outer->data.block.cleanups
4360 = chainon (block->data.block.cleanups,
4361 outer->data.block.cleanups);
4362 block->data.block.cleanups = 0;
4366 last_cleanup_this_contour ()
4368 if (block_stack == 0)
4371 return block_stack->data.block.cleanups;
4374 /* Return 1 if there are any pending cleanups at this point.
4375 If THIS_CONTOUR is nonzero, check the current contour as well.
4376 Otherwise, look only at the contours that enclose this one. */
4379 any_pending_cleanups (this_contour)
4382 struct nesting *block;
4384 if (cfun == NULL || cfun->stmt == NULL || block_stack == 0)
4387 if (this_contour && block_stack->data.block.cleanups != NULL)
4389 if (block_stack->data.block.cleanups == 0
4390 && block_stack->data.block.outer_cleanups == 0)
4393 for (block = block_stack->next; block; block = block->next)
4394 if (block->data.block.cleanups != 0)
4400 /* Enter a case (Pascal) or switch (C) statement.
4401 Push a block onto case_stack and nesting_stack
4402 to accumulate the case-labels that are seen
4403 and to record the labels generated for the statement.
4405 EXIT_FLAG is nonzero if `exit_something' should exit this case stmt.
4406 Otherwise, this construct is transparent for `exit_something'.
4408 EXPR is the index-expression to be dispatched on.
4409 TYPE is its nominal type. We could simply convert EXPR to this type,
4410 but instead we take short cuts. */
4413 expand_start_case (exit_flag, expr, type, printname)
4417 const char *printname;
4419 register struct nesting *thiscase = ALLOC_NESTING ();
4421 /* Make an entry on case_stack for the case we are entering. */
4423 thiscase->next = case_stack;
4424 thiscase->all = nesting_stack;
4425 thiscase->depth = ++nesting_depth;
4426 thiscase->exit_label = exit_flag ? gen_label_rtx () : 0;
4427 thiscase->data.case_stmt.case_list = 0;
4428 thiscase->data.case_stmt.index_expr = expr;
4429 thiscase->data.case_stmt.nominal_type = type;
4430 thiscase->data.case_stmt.default_label = 0;
4431 thiscase->data.case_stmt.num_ranges = 0;
4432 thiscase->data.case_stmt.printname = printname;
4433 thiscase->data.case_stmt.line_number_status = force_line_numbers ();
4434 case_stack = thiscase;
4435 nesting_stack = thiscase;
4437 do_pending_stack_adjust ();
4439 /* Make sure case_stmt.start points to something that won't
4440 need any transformation before expand_end_case. */
4441 if (GET_CODE (get_last_insn ()) != NOTE)
4442 emit_note (NULL_PTR, NOTE_INSN_DELETED);
4444 thiscase->data.case_stmt.start = get_last_insn ();
4446 start_cleanup_deferral ();
4450 /* Start a "dummy case statement" within which case labels are invalid
4451 and are not connected to any larger real case statement.
4452 This can be used if you don't want to let a case statement jump
4453 into the middle of certain kinds of constructs. */
4456 expand_start_case_dummy ()
4458 register struct nesting *thiscase = ALLOC_NESTING ();
4460 /* Make an entry on case_stack for the dummy. */
4462 thiscase->next = case_stack;
4463 thiscase->all = nesting_stack;
4464 thiscase->depth = ++nesting_depth;
4465 thiscase->exit_label = 0;
4466 thiscase->data.case_stmt.case_list = 0;
4467 thiscase->data.case_stmt.start = 0;
4468 thiscase->data.case_stmt.nominal_type = 0;
4469 thiscase->data.case_stmt.default_label = 0;
4470 thiscase->data.case_stmt.num_ranges = 0;
4471 case_stack = thiscase;
4472 nesting_stack = thiscase;
4473 start_cleanup_deferral ();
4476 /* End a dummy case statement. */
4479 expand_end_case_dummy ()
4481 end_cleanup_deferral ();
4482 POPSTACK (case_stack);
4485 /* Return the data type of the index-expression
4486 of the innermost case statement, or null if none. */
4489 case_index_expr_type ()
4492 return TREE_TYPE (case_stack->data.case_stmt.index_expr);
4499 /* If this is the first label, warn if any insns have been emitted. */
4500 if (case_stack->data.case_stmt.line_number_status >= 0)
4504 restore_line_number_status
4505 (case_stack->data.case_stmt.line_number_status);
4506 case_stack->data.case_stmt.line_number_status = -1;
4508 for (insn = case_stack->data.case_stmt.start;
4510 insn = NEXT_INSN (insn))
4512 if (GET_CODE (insn) == CODE_LABEL)
4514 if (GET_CODE (insn) != NOTE
4515 && (GET_CODE (insn) != INSN || GET_CODE (PATTERN (insn)) != USE))
4518 insn = PREV_INSN (insn);
4519 while (insn && (GET_CODE (insn) != NOTE || NOTE_LINE_NUMBER (insn) < 0));
4521 /* If insn is zero, then there must have been a syntax error. */
4523 warning_with_file_and_line (NOTE_SOURCE_FILE(insn),
4524 NOTE_LINE_NUMBER(insn),
4525 "unreachable code at beginning of %s",
4526 case_stack->data.case_stmt.printname);
4533 /* Accumulate one case or default label inside a case or switch statement.
4534 VALUE is the value of the case (a null pointer, for a default label).
4535 The function CONVERTER, when applied to arguments T and V,
4536 converts the value V to the type T.
4538 If not currently inside a case or switch statement, return 1 and do
4539 nothing. The caller will print a language-specific error message.
4540 If VALUE is a duplicate or overlaps, return 2 and do nothing
4541 except store the (first) duplicate node in *DUPLICATE.
4542 If VALUE is out of range, return 3 and do nothing.
4543 If we are jumping into the scope of a cleanup or var-sized array, return 5.
4544 Return 0 on success.
4546 Extended to handle range statements. */
4549 pushcase (value, converter, label, duplicate)
4550 register tree value;
4551 tree (*converter) PARAMS ((tree, tree));
4552 register tree label;
4558 /* Fail if not inside a real case statement. */
4559 if (! (case_stack && case_stack->data.case_stmt.start))
4562 if (stack_block_stack
4563 && stack_block_stack->depth > case_stack->depth)
4566 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4567 nominal_type = case_stack->data.case_stmt.nominal_type;
4569 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4570 if (index_type == error_mark_node)
4573 /* Convert VALUE to the type in which the comparisons are nominally done. */
4575 value = (*converter) (nominal_type, value);
4579 /* Fail if this value is out of range for the actual type of the index
4580 (which may be narrower than NOMINAL_TYPE). */
4582 && (TREE_CONSTANT_OVERFLOW (value)
4583 || ! int_fits_type_p (value, index_type)))
4586 /* Fail if this is a duplicate or overlaps another entry. */
4589 if (case_stack->data.case_stmt.default_label != 0)
4591 *duplicate = case_stack->data.case_stmt.default_label;
4594 case_stack->data.case_stmt.default_label = label;
4597 return add_case_node (value, value, label, duplicate);
4599 expand_label (label);
4603 /* Like pushcase but this case applies to all values between VALUE1 and
4604 VALUE2 (inclusive). If VALUE1 is NULL, the range starts at the lowest
4605 value of the index type and ends at VALUE2. If VALUE2 is NULL, the range
4606 starts at VALUE1 and ends at the highest value of the index type.
4607 If both are NULL, this case applies to all values.
4609 The return value is the same as that of pushcase but there is one
4610 additional error code: 4 means the specified range was empty. */
4613 pushcase_range (value1, value2, converter, label, duplicate)
4614 register tree value1, value2;
4615 tree (*converter) PARAMS ((tree, tree));
4616 register tree label;
4622 /* Fail if not inside a real case statement. */
4623 if (! (case_stack && case_stack->data.case_stmt.start))
4626 if (stack_block_stack
4627 && stack_block_stack->depth > case_stack->depth)
4630 index_type = TREE_TYPE (case_stack->data.case_stmt.index_expr);
4631 nominal_type = case_stack->data.case_stmt.nominal_type;
4633 /* If the index is erroneous, avoid more problems: pretend to succeed. */
4634 if (index_type == error_mark_node)
4639 /* Convert VALUEs to type in which the comparisons are nominally done
4640 and replace any unspecified value with the corresponding bound. */
4642 value1 = TYPE_MIN_VALUE (index_type);
4644 value2 = TYPE_MAX_VALUE (index_type);
4646 /* Fail if the range is empty. Do this before any conversion since
4647 we want to allow out-of-range empty ranges. */
4648 if (value2 != 0 && tree_int_cst_lt (value2, value1))
4651 /* If the max was unbounded, use the max of the nominal_type we are
4652 converting to. Do this after the < check above to suppress false
4655 value2 = TYPE_MAX_VALUE (nominal_type);
4657 value1 = (*converter) (nominal_type, value1);
4658 value2 = (*converter) (nominal_type, value2);
4660 /* Fail if these values are out of range. */
4661 if (TREE_CONSTANT_OVERFLOW (value1)
4662 || ! int_fits_type_p (value1, index_type))
4665 if (TREE_CONSTANT_OVERFLOW (value2)
4666 || ! int_fits_type_p (value2, index_type))
4669 return add_case_node (value1, value2, label, duplicate);
4672 /* Do the actual insertion of a case label for pushcase and pushcase_range
4673 into case_stack->data.case_stmt.case_list. Use an AVL tree to avoid
4674 slowdown for large switch statements. */
4677 add_case_node (low, high, label, duplicate)
4682 struct case_node *p, **q, *r;
4684 q = &case_stack->data.case_stmt.case_list;
4691 /* Keep going past elements distinctly greater than HIGH. */
4692 if (tree_int_cst_lt (high, p->low))
4695 /* or distinctly less than LOW. */
4696 else if (tree_int_cst_lt (p->high, low))
4701 /* We have an overlap; this is an error. */
4702 *duplicate = p->code_label;
4707 /* Add this label to the chain, and succeed.
4708 Copy LOW, HIGH so they are on temporary rather than momentary
4709 obstack and will thus survive till the end of the case statement. */
4711 r = (struct case_node *) oballoc (sizeof (struct case_node));
4712 r->low = copy_node (low);
4714 /* If the bounds are equal, turn this into the one-value case. */
4716 if (tree_int_cst_equal (low, high))
4720 r->high = copy_node (high);
4721 case_stack->data.case_stmt.num_ranges++;
4724 r->code_label = label;
4725 expand_label (label);
4735 struct case_node *s;
4741 if (! (b = p->balance))
4742 /* Growth propagation from left side. */
4749 if ((p->left = s = r->right))
4758 if ((r->parent = s))
4766 case_stack->data.case_stmt.case_list = r;
4769 /* r->balance == +1 */
4774 struct case_node *t = r->right;
4776 if ((p->left = s = t->right))
4780 if ((r->right = s = t->left))
4794 if ((t->parent = s))
4802 case_stack->data.case_stmt.case_list = t;
4809 /* p->balance == +1; growth of left side balances the node. */
4819 if (! (b = p->balance))
4820 /* Growth propagation from right side. */
4828 if ((p->right = s = r->left))
4836 if ((r->parent = s))
4845 case_stack->data.case_stmt.case_list = r;
4849 /* r->balance == -1 */
4853 struct case_node *t = r->left;
4855 if ((p->right = s = t->left))
4860 if ((r->left = s = t->right))
4874 if ((t->parent = s))
4883 case_stack->data.case_stmt.case_list = t;
4889 /* p->balance == -1; growth of right side balances the node. */
4903 /* Returns the number of possible values of TYPE.
4904 Returns -1 if the number is unknown, variable, or if the number does not
4905 fit in a HOST_WIDE_INT.
4906 Sets *SPARENESS to 2 if TYPE is an ENUMERAL_TYPE whose values
4907 do not increase monotonically (there may be duplicates);
4908 to 1 if the values increase monotonically, but not always by 1;
4909 otherwise sets it to 0. */
4912 all_cases_count (type, spareness)
4917 HOST_WIDE_INT count, minval, lastval;
4921 switch (TREE_CODE (type))
4928 count = 1 << BITS_PER_UNIT;
4933 if (TYPE_MAX_VALUE (type) != 0
4934 && 0 != (t = fold (build (MINUS_EXPR, type, TYPE_MAX_VALUE (type),
4935 TYPE_MIN_VALUE (type))))
4936 && 0 != (t = fold (build (PLUS_EXPR, type, t,
4937 convert (type, integer_zero_node))))
4938 && host_integerp (t, 1))
4939 count = tree_low_cst (t, 1);
4945 /* Don't waste time with enumeral types with huge values. */
4946 if (! host_integerp (TYPE_MIN_VALUE (type), 0)
4947 || TYPE_MAX_VALUE (type) == 0
4948 || ! host_integerp (TYPE_MAX_VALUE (type), 0))
4951 lastval = minval = tree_low_cst (TYPE_MIN_VALUE (type), 0);
4954 for (t = TYPE_VALUES (type); t != NULL_TREE; t = TREE_CHAIN (t))
4956 HOST_WIDE_INT thisval = tree_low_cst (TREE_VALUE (t), 0);
4958 if (*spareness == 2 || thisval < lastval)
4960 else if (thisval != minval + count)
4970 #define BITARRAY_TEST(ARRAY, INDEX) \
4971 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4972 & (1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR)))
4973 #define BITARRAY_SET(ARRAY, INDEX) \
4974 ((ARRAY)[(unsigned) (INDEX) / HOST_BITS_PER_CHAR]\
4975 |= 1 << ((unsigned) (INDEX) % HOST_BITS_PER_CHAR))
4977 /* Set the elements of the bitstring CASES_SEEN (which has length COUNT),
4978 with the case values we have seen, assuming the case expression
4980 SPARSENESS is as determined by all_cases_count.
4982 The time needed is proportional to COUNT, unless
4983 SPARSENESS is 2, in which case quadratic time is needed. */
4986 mark_seen_cases (type, cases_seen, count, sparseness)
4988 unsigned char *cases_seen;
4989 HOST_WIDE_INT count;
4992 tree next_node_to_try = NULL_TREE;
4993 HOST_WIDE_INT next_node_offset = 0;
4995 register struct case_node *n, *root = case_stack->data.case_stmt.case_list;
4996 tree val = make_node (INTEGER_CST);
4998 TREE_TYPE (val) = type;
5001 else if (sparseness == 2)
5004 unsigned HOST_WIDE_INT xlo;
5006 /* This less efficient loop is only needed to handle
5007 duplicate case values (multiple enum constants
5008 with the same value). */
5009 TREE_TYPE (val) = TREE_TYPE (root->low);
5010 for (t = TYPE_VALUES (type), xlo = 0; t != NULL_TREE;
5011 t = TREE_CHAIN (t), xlo++)
5013 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (TREE_VALUE (t));
5014 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (TREE_VALUE (t));
5018 /* Keep going past elements distinctly greater than VAL. */
5019 if (tree_int_cst_lt (val, n->low))
5022 /* or distinctly less than VAL. */
5023 else if (tree_int_cst_lt (n->high, val))
5028 /* We have found a matching range. */
5029 BITARRAY_SET (cases_seen, xlo);
5039 case_stack->data.case_stmt.case_list = root = case_tree2list (root, 0);
5041 for (n = root; n; n = n->right)
5043 TREE_INT_CST_LOW (val) = TREE_INT_CST_LOW (n->low);
5044 TREE_INT_CST_HIGH (val) = TREE_INT_CST_HIGH (n->low);
5045 while ( ! tree_int_cst_lt (n->high, val))
5047 /* Calculate (into xlo) the "offset" of the integer (val).
5048 The element with lowest value has offset 0, the next smallest
5049 element has offset 1, etc. */
5051 unsigned HOST_WIDE_INT xlo;
5055 if (sparseness && TYPE_VALUES (type) != NULL_TREE)
5057 /* The TYPE_VALUES will be in increasing order, so
5058 starting searching where we last ended. */
5059 t = next_node_to_try;
5060 xlo = next_node_offset;
5066 t = TYPE_VALUES (type);
5069 if (tree_int_cst_equal (val, TREE_VALUE (t)))
5071 next_node_to_try = TREE_CHAIN (t);
5072 next_node_offset = xlo + 1;
5077 if (t == next_node_to_try)
5086 t = TYPE_MIN_VALUE (type);
5088 neg_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t),
5092 add_double (xlo, xhi,
5093 TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5097 if (xhi == 0 && xlo < (unsigned HOST_WIDE_INT) count)
5098 BITARRAY_SET (cases_seen, xlo);
5100 add_double (TREE_INT_CST_LOW (val), TREE_INT_CST_HIGH (val),
5102 &TREE_INT_CST_LOW (val), &TREE_INT_CST_HIGH (val));
5108 /* Called when the index of a switch statement is an enumerated type
5109 and there is no default label.
5111 Checks that all enumeration literals are covered by the case
5112 expressions of a switch. Also, warn if there are any extra
5113 switch cases that are *not* elements of the enumerated type.
5115 If all enumeration literals were covered by the case expressions,
5116 turn one of the expressions into the default expression since it should
5117 not be possible to fall through such a switch. */
5120 check_for_full_enumeration_handling (type)
5123 register struct case_node *n;
5124 register tree chain;
5125 #if 0 /* variable used by 'if 0'ed code below. */
5126 register struct case_node **l;
5130 /* True iff the selector type is a numbered set mode. */
5133 /* The number of possible selector values. */
5136 /* For each possible selector value. a one iff it has been matched
5137 by a case value alternative. */
5138 unsigned char *cases_seen;
5140 /* The allocated size of cases_seen, in chars. */
5141 HOST_WIDE_INT bytes_needed;
5146 size = all_cases_count (type, &sparseness);
5147 bytes_needed = (size + HOST_BITS_PER_CHAR) / HOST_BITS_PER_CHAR;
5149 if (size > 0 && size < 600000
5150 /* We deliberately use calloc here, not cmalloc, so that we can suppress
5151 this optimization if we don't have enough memory rather than
5152 aborting, as xmalloc would do. */
5153 && (cases_seen = (unsigned char *) calloc (bytes_needed, 1)) != NULL)
5156 tree v = TYPE_VALUES (type);
5158 /* The time complexity of this code is normally O(N), where
5159 N being the number of members in the enumerated type.
5160 However, if type is a ENUMERAL_TYPE whose values do not
5161 increase monotonically, O(N*log(N)) time may be needed. */
5163 mark_seen_cases (type, cases_seen, size, sparseness);
5165 for (i = 0; v != NULL_TREE && i < size; i++, v = TREE_CHAIN (v))
5166 if (BITARRAY_TEST(cases_seen, i) == 0)
5167 warning ("enumeration value `%s' not handled in switch",
5168 IDENTIFIER_POINTER (TREE_PURPOSE (v)));
5173 /* Now we go the other way around; we warn if there are case
5174 expressions that don't correspond to enumerators. This can
5175 occur since C and C++ don't enforce type-checking of
5176 assignments to enumeration variables. */
5178 if (case_stack->data.case_stmt.case_list
5179 && case_stack->data.case_stmt.case_list->left)
5180 case_stack->data.case_stmt.case_list
5181 = case_tree2list (case_stack->data.case_stmt.case_list, 0);
5183 for (n = case_stack->data.case_stmt.case_list; n; n = n->right)
5185 for (chain = TYPE_VALUES (type);
5186 chain && !tree_int_cst_equal (n->low, TREE_VALUE (chain));
5187 chain = TREE_CHAIN (chain))
5192 if (TYPE_NAME (type) == 0)
5193 warning ("case value `%ld' not in enumerated type",
5194 (long) TREE_INT_CST_LOW (n->low));
5196 warning ("case value `%ld' not in enumerated type `%s'",
5197 (long) TREE_INT_CST_LOW (n->low),
5198 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5201 : DECL_NAME (TYPE_NAME (type))));
5203 if (!tree_int_cst_equal (n->low, n->high))
5205 for (chain = TYPE_VALUES (type);
5206 chain && !tree_int_cst_equal (n->high, TREE_VALUE (chain));
5207 chain = TREE_CHAIN (chain))
5212 if (TYPE_NAME (type) == 0)
5213 warning ("case value `%ld' not in enumerated type",
5214 (long) TREE_INT_CST_LOW (n->high));
5216 warning ("case value `%ld' not in enumerated type `%s'",
5217 (long) TREE_INT_CST_LOW (n->high),
5218 IDENTIFIER_POINTER ((TREE_CODE (TYPE_NAME (type))
5221 : DECL_NAME (TYPE_NAME (type))));
5227 /* ??? This optimization is disabled because it causes valid programs to
5228 fail. ANSI C does not guarantee that an expression with enum type
5229 will have a value that is the same as one of the enumeration literals. */
5231 /* If all values were found as case labels, make one of them the default
5232 label. Thus, this switch will never fall through. We arbitrarily pick
5233 the last one to make the default since this is likely the most
5234 efficient choice. */
5238 for (l = &case_stack->data.case_stmt.case_list;
5243 case_stack->data.case_stmt.default_label = (*l)->code_label;
5250 /* Terminate a case (Pascal) or switch (C) statement
5251 in which ORIG_INDEX is the expression to be tested.
5252 Generate the code to test it and jump to the right place. */
5255 expand_end_case (orig_index)
5258 tree minval = NULL_TREE, maxval = NULL_TREE, range = NULL_TREE, orig_minval;
5259 rtx default_label = 0;
5260 register struct case_node *n;
5268 register struct nesting *thiscase = case_stack;
5269 tree index_expr, index_type;
5272 /* Don't crash due to previous errors. */
5273 if (thiscase == NULL)
5276 table_label = gen_label_rtx ();
5277 index_expr = thiscase->data.case_stmt.index_expr;
5278 index_type = TREE_TYPE (index_expr);
5279 unsignedp = TREE_UNSIGNED (index_type);
5281 do_pending_stack_adjust ();
5283 /* This might get an spurious warning in the presence of a syntax error;
5284 it could be fixed by moving the call to check_seenlabel after the
5285 check for error_mark_node, and copying the code of check_seenlabel that
5286 deals with case_stack->data.case_stmt.line_number_status /
5287 restore_line_number_status in front of the call to end_cleanup_deferral;
5288 However, this might miss some useful warnings in the presence of
5289 non-syntax errors. */
5292 /* An ERROR_MARK occurs for various reasons including invalid data type. */
5293 if (index_type != error_mark_node)
5295 /* If switch expression was an enumerated type, check that all
5296 enumeration literals are covered by the cases.
5297 No sense trying this if there's a default case, however. */
5299 if (!thiscase->data.case_stmt.default_label
5300 && TREE_CODE (TREE_TYPE (orig_index)) == ENUMERAL_TYPE
5301 && TREE_CODE (index_expr) != INTEGER_CST)
5302 check_for_full_enumeration_handling (TREE_TYPE (orig_index));
5304 /* If we don't have a default-label, create one here,
5305 after the body of the switch. */
5306 if (thiscase->data.case_stmt.default_label == 0)
5308 thiscase->data.case_stmt.default_label
5309 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
5310 expand_label (thiscase->data.case_stmt.default_label);
5312 default_label = label_rtx (thiscase->data.case_stmt.default_label);
5314 before_case = get_last_insn ();
5316 if (thiscase->data.case_stmt.case_list
5317 && thiscase->data.case_stmt.case_list->left)
5318 thiscase->data.case_stmt.case_list
5319 = case_tree2list(thiscase->data.case_stmt.case_list, 0);
5321 /* Simplify the case-list before we count it. */
5322 group_case_nodes (thiscase->data.case_stmt.case_list);
5324 /* Get upper and lower bounds of case values.
5325 Also convert all the case values to the index expr's data type. */
5328 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5330 /* Check low and high label values are integers. */
5331 if (TREE_CODE (n->low) != INTEGER_CST)
5333 if (TREE_CODE (n->high) != INTEGER_CST)
5336 n->low = convert (index_type, n->low);
5337 n->high = convert (index_type, n->high);
5339 /* Count the elements and track the largest and smallest
5340 of them (treating them as signed even if they are not). */
5348 if (INT_CST_LT (n->low, minval))
5350 if (INT_CST_LT (maxval, n->high))
5353 /* A range counts double, since it requires two compares. */
5354 if (! tree_int_cst_equal (n->low, n->high))
5358 orig_minval = minval;
5360 /* Compute span of values. */
5362 range = fold (build (MINUS_EXPR, index_type, maxval, minval));
5364 end_cleanup_deferral ();
5368 expand_expr (index_expr, const0_rtx, VOIDmode, 0);
5370 emit_jump (default_label);
5373 /* If range of values is much bigger than number of values,
5374 make a sequence of conditional branches instead of a dispatch.
5375 If the switch-index is a constant, do it this way
5376 because we can optimize it. */
5378 #ifndef CASE_VALUES_THRESHOLD
5380 #define CASE_VALUES_THRESHOLD (HAVE_casesi ? 4 : 5)
5382 /* If machine does not have a case insn that compares the
5383 bounds, this means extra overhead for dispatch tables
5384 which raises the threshold for using them. */
5385 #define CASE_VALUES_THRESHOLD 5
5386 #endif /* HAVE_casesi */
5387 #endif /* CASE_VALUES_THRESHOLD */
5389 else if (count < CASE_VALUES_THRESHOLD
5390 || compare_tree_int (range, 10 * count) > 0
5391 /* RANGE may be signed, and really large ranges will show up
5392 as negative numbers. */
5393 || compare_tree_int (range, 0) < 0
5394 #ifndef ASM_OUTPUT_ADDR_DIFF_ELT
5397 || TREE_CODE (index_expr) == INTEGER_CST
5398 /* These will reduce to a constant. */
5399 || (TREE_CODE (index_expr) == CALL_EXPR
5400 && TREE_CODE (TREE_OPERAND (index_expr, 0)) == ADDR_EXPR
5401 && TREE_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == FUNCTION_DECL
5402 && DECL_BUILT_IN_CLASS (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_NORMAL
5403 && DECL_FUNCTION_CODE (TREE_OPERAND (TREE_OPERAND (index_expr, 0), 0)) == BUILT_IN_CLASSIFY_TYPE)
5404 || (TREE_CODE (index_expr) == COMPOUND_EXPR
5405 && TREE_CODE (TREE_OPERAND (index_expr, 1)) == INTEGER_CST))
5407 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5409 /* If the index is a short or char that we do not have
5410 an insn to handle comparisons directly, convert it to
5411 a full integer now, rather than letting each comparison
5412 generate the conversion. */
5414 if (GET_MODE_CLASS (GET_MODE (index)) == MODE_INT
5415 && (cmp_optab->handlers[(int) GET_MODE(index)].insn_code
5416 == CODE_FOR_nothing))
5418 enum machine_mode wider_mode;
5419 for (wider_mode = GET_MODE (index); wider_mode != VOIDmode;
5420 wider_mode = GET_MODE_WIDER_MODE (wider_mode))
5421 if (cmp_optab->handlers[(int) wider_mode].insn_code
5422 != CODE_FOR_nothing)
5424 index = convert_to_mode (wider_mode, index, unsignedp);
5430 do_pending_stack_adjust ();
5432 index = protect_from_queue (index, 0);
5433 if (GET_CODE (index) == MEM)
5434 index = copy_to_reg (index);
5435 if (GET_CODE (index) == CONST_INT
5436 || TREE_CODE (index_expr) == INTEGER_CST)
5438 /* Make a tree node with the proper constant value
5439 if we don't already have one. */
5440 if (TREE_CODE (index_expr) != INTEGER_CST)
5443 = build_int_2 (INTVAL (index),
5444 unsignedp || INTVAL (index) >= 0 ? 0 : -1);
5445 index_expr = convert (index_type, index_expr);
5448 /* For constant index expressions we need only
5449 issue a unconditional branch to the appropriate
5450 target code. The job of removing any unreachable
5451 code is left to the optimisation phase if the
5452 "-O" option is specified. */
5453 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5454 if (! tree_int_cst_lt (index_expr, n->low)
5455 && ! tree_int_cst_lt (n->high, index_expr))
5459 emit_jump (label_rtx (n->code_label));
5461 emit_jump (default_label);
5465 /* If the index expression is not constant we generate
5466 a binary decision tree to select the appropriate
5467 target code. This is done as follows:
5469 The list of cases is rearranged into a binary tree,
5470 nearly optimal assuming equal probability for each case.
5472 The tree is transformed into RTL, eliminating
5473 redundant test conditions at the same time.
5475 If program flow could reach the end of the
5476 decision tree an unconditional jump to the
5477 default code is emitted. */
5480 = (TREE_CODE (TREE_TYPE (orig_index)) != ENUMERAL_TYPE
5481 && estimate_case_costs (thiscase->data.case_stmt.case_list));
5482 balance_case_nodes (&thiscase->data.case_stmt.case_list,
5484 emit_case_nodes (index, thiscase->data.case_stmt.case_list,
5485 default_label, index_type);
5486 emit_jump_if_reachable (default_label);
5495 enum machine_mode index_mode = SImode;
5496 int index_bits = GET_MODE_BITSIZE (index_mode);
5498 enum machine_mode op_mode;
5500 /* Convert the index to SImode. */
5501 if (GET_MODE_BITSIZE (TYPE_MODE (index_type))
5502 > GET_MODE_BITSIZE (index_mode))
5504 enum machine_mode omode = TYPE_MODE (index_type);
5505 rtx rangertx = expand_expr (range, NULL_RTX, VOIDmode, 0);
5507 /* We must handle the endpoints in the original mode. */
5508 index_expr = build (MINUS_EXPR, index_type,
5509 index_expr, minval);
5510 minval = integer_zero_node;
5511 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5512 emit_cmp_and_jump_insns (rangertx, index, LTU, NULL_RTX,
5513 omode, 1, 0, default_label);
5514 /* Now we can safely truncate. */
5515 index = convert_to_mode (index_mode, index, 0);
5519 if (TYPE_MODE (index_type) != index_mode)
5521 index_expr = convert (type_for_size (index_bits, 0),
5523 index_type = TREE_TYPE (index_expr);
5526 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5529 index = protect_from_queue (index, 0);
5530 do_pending_stack_adjust ();
5532 op_mode = insn_data[(int)CODE_FOR_casesi].operand[0].mode;
5533 if (! (*insn_data[(int)CODE_FOR_casesi].operand[0].predicate)
5535 index = copy_to_mode_reg (op_mode, index);
5537 op1 = expand_expr (minval, NULL_RTX, VOIDmode, 0);
5539 op_mode = insn_data[(int)CODE_FOR_casesi].operand[1].mode;
5540 if (! (*insn_data[(int)CODE_FOR_casesi].operand[1].predicate)
5542 op1 = copy_to_mode_reg (op_mode, op1);
5544 op2 = expand_expr (range, NULL_RTX, VOIDmode, 0);
5546 op_mode = insn_data[(int)CODE_FOR_casesi].operand[2].mode;
5547 if (! (*insn_data[(int)CODE_FOR_casesi].operand[2].predicate)
5549 op2 = copy_to_mode_reg (op_mode, op2);
5551 emit_jump_insn (gen_casesi (index, op1, op2,
5552 table_label, default_label));
5556 #ifdef HAVE_tablejump
5557 if (! win && HAVE_tablejump)
5559 index_expr = convert (thiscase->data.case_stmt.nominal_type,
5560 fold (build (MINUS_EXPR, index_type,
5561 index_expr, minval)));
5562 index_type = TREE_TYPE (index_expr);
5563 index = expand_expr (index_expr, NULL_RTX, VOIDmode, 0);
5565 index = protect_from_queue (index, 0);
5566 do_pending_stack_adjust ();
5568 do_tablejump (index, TYPE_MODE (index_type),
5569 expand_expr (range, NULL_RTX, VOIDmode, 0),
5570 table_label, default_label);
5577 /* Get table of labels to jump to, in order of case index. */
5579 ncases = TREE_INT_CST_LOW (range) + 1;
5580 labelvec = (rtx *) alloca (ncases * sizeof (rtx));
5581 bzero ((char *) labelvec, ncases * sizeof (rtx));
5583 for (n = thiscase->data.case_stmt.case_list; n; n = n->right)
5585 register HOST_WIDE_INT i
5586 = TREE_INT_CST_LOW (n->low) - TREE_INT_CST_LOW (orig_minval);
5591 = gen_rtx_LABEL_REF (Pmode, label_rtx (n->code_label));
5592 if (i + TREE_INT_CST_LOW (orig_minval)
5593 == TREE_INT_CST_LOW (n->high))
5599 /* Fill in the gaps with the default. */
5600 for (i = 0; i < ncases; i++)
5601 if (labelvec[i] == 0)
5602 labelvec[i] = gen_rtx_LABEL_REF (Pmode, default_label);
5604 /* Output the table */
5605 emit_label (table_label);
5607 if (CASE_VECTOR_PC_RELATIVE || flag_pic)
5608 emit_jump_insn (gen_rtx_ADDR_DIFF_VEC (CASE_VECTOR_MODE,
5609 gen_rtx_LABEL_REF (Pmode, table_label),
5610 gen_rtvec_v (ncases, labelvec),
5611 const0_rtx, const0_rtx));
5613 emit_jump_insn (gen_rtx_ADDR_VEC (CASE_VECTOR_MODE,
5614 gen_rtvec_v (ncases, labelvec)));
5616 /* If the case insn drops through the table,
5617 after the table we must jump to the default-label.
5618 Otherwise record no drop-through after the table. */
5619 #ifdef CASE_DROPS_THROUGH
5620 emit_jump (default_label);
5626 before_case = squeeze_notes (NEXT_INSN (before_case), get_last_insn ());
5627 reorder_insns (before_case, get_last_insn (),
5628 thiscase->data.case_stmt.start);
5631 end_cleanup_deferral ();
5633 if (thiscase->exit_label)
5634 emit_label (thiscase->exit_label);
5636 POPSTACK (case_stack);
5641 /* Convert the tree NODE into a list linked by the right field, with the left
5642 field zeroed. RIGHT is used for recursion; it is a list to be placed
5643 rightmost in the resulting list. */
5645 static struct case_node *
5646 case_tree2list (node, right)
5647 struct case_node *node, *right;
5649 struct case_node *left;
5652 right = case_tree2list (node->right, right);
5654 node->right = right;
5655 if ((left = node->left))
5658 return case_tree2list (left, node);
5664 /* Generate code to jump to LABEL if OP1 and OP2 are equal. */
5667 do_jump_if_equal (op1, op2, label, unsignedp)
5668 rtx op1, op2, label;
5671 if (GET_CODE (op1) == CONST_INT
5672 && GET_CODE (op2) == CONST_INT)
5674 if (INTVAL (op1) == INTVAL (op2))
5679 enum machine_mode mode = GET_MODE (op1);
5680 if (mode == VOIDmode)
5681 mode = GET_MODE (op2);
5682 emit_cmp_and_jump_insns (op1, op2, EQ, NULL_RTX, mode, unsignedp,
5687 /* Not all case values are encountered equally. This function
5688 uses a heuristic to weight case labels, in cases where that
5689 looks like a reasonable thing to do.
5691 Right now, all we try to guess is text, and we establish the
5694 chars above space: 16
5703 If we find any cases in the switch that are not either -1 or in the range
5704 of valid ASCII characters, or are control characters other than those
5705 commonly used with "\", don't treat this switch scanning text.
5707 Return 1 if these nodes are suitable for cost estimation, otherwise
5711 estimate_case_costs (node)
5714 tree min_ascii = build_int_2 (-1, -1);
5715 tree max_ascii = convert (TREE_TYPE (node->high), build_int_2 (127, 0));
5719 /* If we haven't already made the cost table, make it now. Note that the
5720 lower bound of the table is -1, not zero. */
5722 if (cost_table == NULL)
5724 cost_table = cost_table_ + 1;
5726 for (i = 0; i < 128; i++)
5730 else if (ISPUNCT (i))
5732 else if (ISCNTRL (i))
5736 cost_table[' '] = 8;
5737 cost_table['\t'] = 4;
5738 cost_table['\0'] = 4;
5739 cost_table['\n'] = 2;
5740 cost_table['\f'] = 1;
5741 cost_table['\v'] = 1;
5742 cost_table['\b'] = 1;
5745 /* See if all the case expressions look like text. It is text if the
5746 constant is >= -1 and the highest constant is <= 127. Do all comparisons
5747 as signed arithmetic since we don't want to ever access cost_table with a
5748 value less than -1. Also check that none of the constants in a range
5749 are strange control characters. */
5751 for (n = node; n; n = n->right)
5753 if ((INT_CST_LT (n->low, min_ascii)) || INT_CST_LT (max_ascii, n->high))
5756 for (i = (HOST_WIDE_INT) TREE_INT_CST_LOW (n->low);
5757 i <= (HOST_WIDE_INT) TREE_INT_CST_LOW (n->high); i++)
5758 if (cost_table[i] < 0)
5762 /* All interesting values are within the range of interesting
5763 ASCII characters. */
5767 /* Scan an ordered list of case nodes
5768 combining those with consecutive values or ranges.
5770 Eg. three separate entries 1: 2: 3: become one entry 1..3: */
5773 group_case_nodes (head)
5776 case_node_ptr node = head;
5780 rtx lb = next_real_insn (label_rtx (node->code_label));
5782 case_node_ptr np = node;
5784 /* Try to group the successors of NODE with NODE. */
5785 while (((np = np->right) != 0)
5786 /* Do they jump to the same place? */
5787 && ((lb2 = next_real_insn (label_rtx (np->code_label))) == lb
5788 || (lb != 0 && lb2 != 0
5789 && simplejump_p (lb)
5790 && simplejump_p (lb2)
5791 && rtx_equal_p (SET_SRC (PATTERN (lb)),
5792 SET_SRC (PATTERN (lb2)))))
5793 /* Are their ranges consecutive? */
5794 && tree_int_cst_equal (np->low,
5795 fold (build (PLUS_EXPR,
5796 TREE_TYPE (node->high),
5799 /* An overflow is not consecutive. */
5800 && tree_int_cst_lt (node->high,
5801 fold (build (PLUS_EXPR,
5802 TREE_TYPE (node->high),
5804 integer_one_node))))
5806 node->high = np->high;
5808 /* NP is the first node after NODE which can't be grouped with it.
5809 Delete the nodes in between, and move on to that node. */
5815 /* Take an ordered list of case nodes
5816 and transform them into a near optimal binary tree,
5817 on the assumption that any target code selection value is as
5818 likely as any other.
5820 The transformation is performed by splitting the ordered
5821 list into two equal sections plus a pivot. The parts are
5822 then attached to the pivot as left and right branches. Each
5823 branch is then transformed recursively. */
5826 balance_case_nodes (head, parent)
5827 case_node_ptr *head;
5828 case_node_ptr parent;
5830 register case_node_ptr np;
5838 register case_node_ptr *npp;
5841 /* Count the number of entries on branch. Also count the ranges. */
5845 if (!tree_int_cst_equal (np->low, np->high))
5849 cost += cost_table[TREE_INT_CST_LOW (np->high)];
5853 cost += cost_table[TREE_INT_CST_LOW (np->low)];
5861 /* Split this list if it is long enough for that to help. */
5866 /* Find the place in the list that bisects the list's total cost,
5867 Here I gets half the total cost. */
5872 /* Skip nodes while their cost does not reach that amount. */
5873 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5874 i -= cost_table[TREE_INT_CST_LOW ((*npp)->high)];
5875 i -= cost_table[TREE_INT_CST_LOW ((*npp)->low)];
5878 npp = &(*npp)->right;
5883 /* Leave this branch lopsided, but optimize left-hand
5884 side and fill in `parent' fields for right-hand side. */
5886 np->parent = parent;
5887 balance_case_nodes (&np->left, np);
5888 for (; np->right; np = np->right)
5889 np->right->parent = np;
5893 /* If there are just three nodes, split at the middle one. */
5895 npp = &(*npp)->right;
5898 /* Find the place in the list that bisects the list's total cost,
5899 where ranges count as 2.
5900 Here I gets half the total cost. */
5901 i = (i + ranges + 1) / 2;
5904 /* Skip nodes while their cost does not reach that amount. */
5905 if (!tree_int_cst_equal ((*npp)->low, (*npp)->high))
5910 npp = &(*npp)->right;
5915 np->parent = parent;
5918 /* Optimize each of the two split parts. */
5919 balance_case_nodes (&np->left, np);
5920 balance_case_nodes (&np->right, np);
5924 /* Else leave this branch as one level,
5925 but fill in `parent' fields. */
5927 np->parent = parent;
5928 for (; np->right; np = np->right)
5929 np->right->parent = np;
5934 /* Search the parent sections of the case node tree
5935 to see if a test for the lower bound of NODE would be redundant.
5936 INDEX_TYPE is the type of the index expression.
5938 The instructions to generate the case decision tree are
5939 output in the same order as nodes are processed so it is
5940 known that if a parent node checks the range of the current
5941 node minus one that the current node is bounded at its lower
5942 span. Thus the test would be redundant. */
5945 node_has_low_bound (node, index_type)
5950 case_node_ptr pnode;
5952 /* If the lower bound of this node is the lowest value in the index type,
5953 we need not test it. */
5955 if (tree_int_cst_equal (node->low, TYPE_MIN_VALUE (index_type)))
5958 /* If this node has a left branch, the value at the left must be less
5959 than that at this node, so it cannot be bounded at the bottom and
5960 we need not bother testing any further. */
5965 low_minus_one = fold (build (MINUS_EXPR, TREE_TYPE (node->low),
5966 node->low, integer_one_node));
5968 /* If the subtraction above overflowed, we can't verify anything.
5969 Otherwise, look for a parent that tests our value - 1. */
5971 if (! tree_int_cst_lt (low_minus_one, node->low))
5974 for (pnode = node->parent; pnode; pnode = pnode->parent)
5975 if (tree_int_cst_equal (low_minus_one, pnode->high))
5981 /* Search the parent sections of the case node tree
5982 to see if a test for the upper bound of NODE would be redundant.
5983 INDEX_TYPE is the type of the index expression.
5985 The instructions to generate the case decision tree are
5986 output in the same order as nodes are processed so it is
5987 known that if a parent node checks the range of the current
5988 node plus one that the current node is bounded at its upper
5989 span. Thus the test would be redundant. */
5992 node_has_high_bound (node, index_type)
5997 case_node_ptr pnode;
5999 /* If there is no upper bound, obviously no test is needed. */
6001 if (TYPE_MAX_VALUE (index_type) == NULL)
6004 /* If the upper bound of this node is the highest value in the type
6005 of the index expression, we need not test against it. */
6007 if (tree_int_cst_equal (node->high, TYPE_MAX_VALUE (index_type)))
6010 /* If this node has a right branch, the value at the right must be greater
6011 than that at this node, so it cannot be bounded at the top and
6012 we need not bother testing any further. */
6017 high_plus_one = fold (build (PLUS_EXPR, TREE_TYPE (node->high),
6018 node->high, integer_one_node));
6020 /* If the addition above overflowed, we can't verify anything.
6021 Otherwise, look for a parent that tests our value + 1. */
6023 if (! tree_int_cst_lt (node->high, high_plus_one))
6026 for (pnode = node->parent; pnode; pnode = pnode->parent)
6027 if (tree_int_cst_equal (high_plus_one, pnode->low))
6033 /* Search the parent sections of the
6034 case node tree to see if both tests for the upper and lower
6035 bounds of NODE would be redundant. */
6038 node_is_bounded (node, index_type)
6042 return (node_has_low_bound (node, index_type)
6043 && node_has_high_bound (node, index_type));
6046 /* Emit an unconditional jump to LABEL unless it would be dead code. */
6049 emit_jump_if_reachable (label)
6052 if (GET_CODE (get_last_insn ()) != BARRIER)
6056 /* Emit step-by-step code to select a case for the value of INDEX.
6057 The thus generated decision tree follows the form of the
6058 case-node binary tree NODE, whose nodes represent test conditions.
6059 INDEX_TYPE is the type of the index of the switch.
6061 Care is taken to prune redundant tests from the decision tree
6062 by detecting any boundary conditions already checked by
6063 emitted rtx. (See node_has_high_bound, node_has_low_bound
6064 and node_is_bounded, above.)
6066 Where the test conditions can be shown to be redundant we emit
6067 an unconditional jump to the target code. As a further
6068 optimization, the subordinates of a tree node are examined to
6069 check for bounded nodes. In this case conditional and/or
6070 unconditional jumps as a result of the boundary check for the
6071 current node are arranged to target the subordinates associated
6072 code for out of bound conditions on the current node.
6074 We can assume that when control reaches the code generated here,
6075 the index value has already been compared with the parents
6076 of this node, and determined to be on the same side of each parent
6077 as this node is. Thus, if this node tests for the value 51,
6078 and a parent tested for 52, we don't need to consider
6079 the possibility of a value greater than 51. If another parent
6080 tests for the value 50, then this node need not test anything. */
6083 emit_case_nodes (index, node, default_label, index_type)
6089 /* If INDEX has an unsigned type, we must make unsigned branches. */
6090 int unsignedp = TREE_UNSIGNED (index_type);
6091 enum machine_mode mode = GET_MODE (index);
6093 /* See if our parents have already tested everything for us.
6094 If they have, emit an unconditional jump for this node. */
6095 if (node_is_bounded (node, index_type))
6096 emit_jump (label_rtx (node->code_label));
6098 else if (tree_int_cst_equal (node->low, node->high))
6100 /* Node is single valued. First see if the index expression matches
6101 this node and then check our children, if any. */
6103 do_jump_if_equal (index, expand_expr (node->low, NULL_RTX, VOIDmode, 0),
6104 label_rtx (node->code_label), unsignedp);
6106 if (node->right != 0 && node->left != 0)
6108 /* This node has children on both sides.
6109 Dispatch to one side or the other
6110 by comparing the index value with this node's value.
6111 If one subtree is bounded, check that one first,
6112 so we can avoid real branches in the tree. */
6114 if (node_is_bounded (node->right, index_type))
6116 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6118 GT, NULL_RTX, mode, unsignedp, 0,
6119 label_rtx (node->right->code_label));
6120 emit_case_nodes (index, node->left, default_label, index_type);
6123 else if (node_is_bounded (node->left, index_type))
6125 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6127 LT, NULL_RTX, mode, unsignedp, 0,
6128 label_rtx (node->left->code_label));
6129 emit_case_nodes (index, node->right, default_label, index_type);
6134 /* Neither node is bounded. First distinguish the two sides;
6135 then emit the code for one side at a time. */
6138 = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6140 /* See if the value is on the right. */
6141 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6143 GT, NULL_RTX, mode, unsignedp, 0,
6144 label_rtx (test_label));
6146 /* Value must be on the left.
6147 Handle the left-hand subtree. */
6148 emit_case_nodes (index, node->left, default_label, index_type);
6149 /* If left-hand subtree does nothing,
6151 emit_jump_if_reachable (default_label);
6153 /* Code branches here for the right-hand subtree. */
6154 expand_label (test_label);
6155 emit_case_nodes (index, node->right, default_label, index_type);
6159 else if (node->right != 0 && node->left == 0)
6161 /* Here we have a right child but no left so we issue conditional
6162 branch to default and process the right child.
6164 Omit the conditional branch to default if we it avoid only one
6165 right child; it costs too much space to save so little time. */
6167 if (node->right->right || node->right->left
6168 || !tree_int_cst_equal (node->right->low, node->right->high))
6170 if (!node_has_low_bound (node, index_type))
6172 emit_cmp_and_jump_insns (index, expand_expr (node->high,
6175 LT, NULL_RTX, mode, unsignedp, 0,
6179 emit_case_nodes (index, node->right, default_label, index_type);
6182 /* We cannot process node->right normally
6183 since we haven't ruled out the numbers less than
6184 this node's value. So handle node->right explicitly. */
6185 do_jump_if_equal (index,
6186 expand_expr (node->right->low, NULL_RTX,
6188 label_rtx (node->right->code_label), unsignedp);
6191 else if (node->right == 0 && node->left != 0)
6193 /* Just one subtree, on the left. */
6195 #if 0 /* The following code and comment were formerly part
6196 of the condition here, but they didn't work
6197 and I don't understand what the idea was. -- rms. */
6198 /* If our "most probable entry" is less probable
6199 than the default label, emit a jump to
6200 the default label using condition codes
6201 already lying around. With no right branch,
6202 a branch-greater-than will get us to the default
6205 && cost_table[TREE_INT_CST_LOW (node->high)] < 12)
6208 if (node->left->left || node->left->right
6209 || !tree_int_cst_equal (node->left->low, node->left->high))
6211 if (!node_has_high_bound (node, index_type))
6213 emit_cmp_and_jump_insns (index, expand_expr (node->high,
6216 GT, NULL_RTX, mode, unsignedp, 0,
6220 emit_case_nodes (index, node->left, default_label, index_type);
6223 /* We cannot process node->left normally
6224 since we haven't ruled out the numbers less than
6225 this node's value. So handle node->left explicitly. */
6226 do_jump_if_equal (index,
6227 expand_expr (node->left->low, NULL_RTX,
6229 label_rtx (node->left->code_label), unsignedp);
6234 /* Node is a range. These cases are very similar to those for a single
6235 value, except that we do not start by testing whether this node
6236 is the one to branch to. */
6238 if (node->right != 0 && node->left != 0)
6240 /* Node has subtrees on both sides.
6241 If the right-hand subtree is bounded,
6242 test for it first, since we can go straight there.
6243 Otherwise, we need to make a branch in the control structure,
6244 then handle the two subtrees. */
6245 tree test_label = 0;
6248 if (node_is_bounded (node->right, index_type))
6249 /* Right hand node is fully bounded so we can eliminate any
6250 testing and branch directly to the target code. */
6251 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6253 GT, NULL_RTX, mode, unsignedp, 0,
6254 label_rtx (node->right->code_label));
6257 /* Right hand node requires testing.
6258 Branch to a label where we will handle it later. */
6260 test_label = build_decl (LABEL_DECL, NULL_TREE, NULL_TREE);
6261 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6263 GT, NULL_RTX, mode, unsignedp, 0,
6264 label_rtx (test_label));
6267 /* Value belongs to this node or to the left-hand subtree. */
6269 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6271 GE, NULL_RTX, mode, unsignedp, 0,
6272 label_rtx (node->code_label));
6274 /* Handle the left-hand subtree. */
6275 emit_case_nodes (index, node->left, default_label, index_type);
6277 /* If right node had to be handled later, do that now. */
6281 /* If the left-hand subtree fell through,
6282 don't let it fall into the right-hand subtree. */
6283 emit_jump_if_reachable (default_label);
6285 expand_label (test_label);
6286 emit_case_nodes (index, node->right, default_label, index_type);
6290 else if (node->right != 0 && node->left == 0)
6292 /* Deal with values to the left of this node,
6293 if they are possible. */
6294 if (!node_has_low_bound (node, index_type))
6296 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6298 LT, NULL_RTX, mode, unsignedp, 0,
6302 /* Value belongs to this node or to the right-hand subtree. */
6304 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6306 LE, NULL_RTX, mode, unsignedp, 0,
6307 label_rtx (node->code_label));
6309 emit_case_nodes (index, node->right, default_label, index_type);
6312 else if (node->right == 0 && node->left != 0)
6314 /* Deal with values to the right of this node,
6315 if they are possible. */
6316 if (!node_has_high_bound (node, index_type))
6318 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6320 GT, NULL_RTX, mode, unsignedp, 0,
6324 /* Value belongs to this node or to the left-hand subtree. */
6326 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6328 GE, NULL_RTX, mode, unsignedp, 0,
6329 label_rtx (node->code_label));
6331 emit_case_nodes (index, node->left, default_label, index_type);
6336 /* Node has no children so we check low and high bounds to remove
6337 redundant tests. Only one of the bounds can exist,
6338 since otherwise this node is bounded--a case tested already. */
6340 if (!node_has_high_bound (node, index_type))
6342 emit_cmp_and_jump_insns (index, expand_expr (node->high, NULL_RTX,
6344 GT, NULL_RTX, mode, unsignedp, 0,
6348 if (!node_has_low_bound (node, index_type))
6350 emit_cmp_and_jump_insns (index, expand_expr (node->low, NULL_RTX,
6352 LT, NULL_RTX, mode, unsignedp, 0,
6356 emit_jump (label_rtx (node->code_label));