1 /* Language-independent node constructors for parse phase of GNU compiler.
2 Copyright (C) 1987, 1988, 1992, 1993, 1994 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 /* This file contains the low level primitives for operating on tree nodes,
22 including allocation, list operations, interning of identifiers,
23 construction of data type nodes and statement nodes,
24 and construction of type conversion nodes. It also contains
25 tables index by tree code that describe how to take apart
28 It is intended to be language-independent, but occasionally
29 calls language-dependent routines defined (for C) in typecheck.c.
31 The low-level allocation routines oballoc and permalloc
32 are used also for allocating many other kinds of objects
33 by all passes of the compiler. */
47 #define obstack_chunk_alloc xmalloc
48 #define obstack_chunk_free free
50 /* Tree nodes of permanent duration are allocated in this obstack.
51 They are the identifier nodes, and everything outside of
52 the bodies and parameters of function definitions. */
54 struct obstack permanent_obstack;
56 /* The initial RTL, and all ..._TYPE nodes, in a function
57 are allocated in this obstack. Usually they are freed at the
58 end of the function, but if the function is inline they are saved.
59 For top-level functions, this is maybepermanent_obstack.
60 Separate obstacks are made for nested functions. */
62 struct obstack *function_maybepermanent_obstack;
64 /* This is the function_maybepermanent_obstack for top-level functions. */
66 struct obstack maybepermanent_obstack;
68 /* The contents of the current function definition are allocated
69 in this obstack, and all are freed at the end of the function.
70 For top-level functions, this is temporary_obstack.
71 Separate obstacks are made for nested functions. */
73 struct obstack *function_obstack;
75 /* This is used for reading initializers of global variables. */
77 struct obstack temporary_obstack;
79 /* The tree nodes of an expression are allocated
80 in this obstack, and all are freed at the end of the expression. */
82 struct obstack momentary_obstack;
84 /* The tree nodes of a declarator are allocated
85 in this obstack, and all are freed when the declarator
88 static struct obstack temp_decl_obstack;
90 /* This points at either permanent_obstack
91 or the current function_maybepermanent_obstack. */
93 struct obstack *saveable_obstack;
95 /* This is same as saveable_obstack during parse and expansion phase;
96 it points to the current function's obstack during optimization.
97 This is the obstack to be used for creating rtl objects. */
99 struct obstack *rtl_obstack;
101 /* This points at either permanent_obstack or the current function_obstack. */
103 struct obstack *current_obstack;
105 /* This points at either permanent_obstack or the current function_obstack
106 or momentary_obstack. */
108 struct obstack *expression_obstack;
110 /* Stack of obstack selections for push_obstacks and pop_obstacks. */
114 struct obstack_stack *next;
115 struct obstack *current;
116 struct obstack *saveable;
117 struct obstack *expression;
121 struct obstack_stack *obstack_stack;
123 /* Obstack for allocating struct obstack_stack entries. */
125 static struct obstack obstack_stack_obstack;
127 /* Addresses of first objects in some obstacks.
128 This is for freeing their entire contents. */
129 char *maybepermanent_firstobj;
130 char *temporary_firstobj;
131 char *momentary_firstobj;
132 char *temp_decl_firstobj;
134 /* Nonzero means all ..._TYPE nodes should be allocated permanently. */
136 int all_types_permanent;
138 /* Stack of places to restore the momentary obstack back to. */
140 struct momentary_level
142 /* Pointer back to previous such level. */
143 struct momentary_level *prev;
144 /* First object allocated within this level. */
146 /* Value of expression_obstack saved at entry to this level. */
147 struct obstack *obstack;
150 struct momentary_level *momentary_stack;
152 /* Table indexed by tree code giving a string containing a character
153 classifying the tree code. Possibilities are
154 t, d, s, c, r, <, 1, 2 and e. See tree.def for details. */
156 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,
158 char *standard_tree_code_type[] = {
163 /* Table indexed by tree code giving number of expression
164 operands beyond the fixed part of the node structure.
165 Not used for types or decls. */
167 #define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,
169 int standard_tree_code_length[] = {
174 /* Names of tree components.
175 Used for printing out the tree and error messages. */
176 #define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,
178 char *standard_tree_code_name[] = {
183 /* Table indexed by tree code giving a string containing a character
184 classifying the tree code. Possibilities are
185 t, d, s, c, r, e, <, 1 and 2. See tree.def for details. */
187 char **tree_code_type;
189 /* Table indexed by tree code giving number of expression
190 operands beyond the fixed part of the node structure.
191 Not used for types or decls. */
193 int *tree_code_length;
195 /* Table indexed by tree code giving name of tree code, as a string. */
197 char **tree_code_name;
199 /* Statistics-gathering stuff. */
220 int tree_node_counts[(int)all_kinds];
221 int tree_node_sizes[(int)all_kinds];
222 int id_string_size = 0;
224 char *tree_node_kind_names[] = {
242 /* Hash table for uniquizing IDENTIFIER_NODEs by name. */
244 #define MAX_HASH_TABLE 1009
245 static tree hash_table[MAX_HASH_TABLE]; /* id hash buckets */
247 /* 0 while creating built-in identifiers. */
248 static int do_identifier_warnings;
250 /* Unique id for next decl created. */
251 static int next_decl_uid;
252 /* Unique id for next type created. */
253 static int next_type_uid = 1;
255 extern char *mode_name[];
257 void gcc_obstack_init ();
258 static tree stabilize_reference_1 ();
260 /* Init the principal obstacks. */
265 gcc_obstack_init (&obstack_stack_obstack);
266 gcc_obstack_init (&permanent_obstack);
268 gcc_obstack_init (&temporary_obstack);
269 temporary_firstobj = (char *) obstack_alloc (&temporary_obstack, 0);
270 gcc_obstack_init (&momentary_obstack);
271 momentary_firstobj = (char *) obstack_alloc (&momentary_obstack, 0);
272 gcc_obstack_init (&maybepermanent_obstack);
273 maybepermanent_firstobj
274 = (char *) obstack_alloc (&maybepermanent_obstack, 0);
275 gcc_obstack_init (&temp_decl_obstack);
276 temp_decl_firstobj = (char *) obstack_alloc (&temp_decl_obstack, 0);
278 function_obstack = &temporary_obstack;
279 function_maybepermanent_obstack = &maybepermanent_obstack;
280 current_obstack = &permanent_obstack;
281 expression_obstack = &permanent_obstack;
282 rtl_obstack = saveable_obstack = &permanent_obstack;
284 /* Init the hash table of identifiers. */
285 bzero (hash_table, sizeof hash_table);
289 gcc_obstack_init (obstack)
290 struct obstack *obstack;
292 /* Let particular systems override the size of a chunk. */
293 #ifndef OBSTACK_CHUNK_SIZE
294 #define OBSTACK_CHUNK_SIZE 0
296 /* Let them override the alloc and free routines too. */
297 #ifndef OBSTACK_CHUNK_ALLOC
298 #define OBSTACK_CHUNK_ALLOC xmalloc
300 #ifndef OBSTACK_CHUNK_FREE
301 #define OBSTACK_CHUNK_FREE free
303 _obstack_begin (obstack, OBSTACK_CHUNK_SIZE, 0,
304 (void *(*) ()) OBSTACK_CHUNK_ALLOC,
305 (void (*) ()) OBSTACK_CHUNK_FREE);
308 /* Save all variables describing the current status into the structure *P.
309 This is used before starting a nested function. */
315 p->all_types_permanent = all_types_permanent;
316 p->momentary_stack = momentary_stack;
317 p->maybepermanent_firstobj = maybepermanent_firstobj;
318 p->momentary_firstobj = momentary_firstobj;
319 p->function_obstack = function_obstack;
320 p->function_maybepermanent_obstack = function_maybepermanent_obstack;
321 p->current_obstack = current_obstack;
322 p->expression_obstack = expression_obstack;
323 p->saveable_obstack = saveable_obstack;
324 p->rtl_obstack = rtl_obstack;
326 /* Objects that need to be saved in this function can be in the nonsaved
327 obstack of the enclosing function since they can't possibly be needed
328 once it has returned. */
329 function_maybepermanent_obstack = function_obstack;
331 function_obstack = (struct obstack *) xmalloc (sizeof (struct obstack));
332 gcc_obstack_init (function_obstack);
334 current_obstack = &permanent_obstack;
335 expression_obstack = &permanent_obstack;
336 rtl_obstack = saveable_obstack = &permanent_obstack;
338 momentary_firstobj = (char *) obstack_finish (&momentary_obstack);
339 maybepermanent_firstobj
340 = (char *) obstack_finish (function_maybepermanent_obstack);
343 /* Restore all variables describing the current status from the structure *P.
344 This is used after a nested function. */
347 restore_tree_status (p)
350 all_types_permanent = p->all_types_permanent;
351 momentary_stack = p->momentary_stack;
353 obstack_free (&momentary_obstack, momentary_firstobj);
355 /* Free saveable storage used by the function just compiled and not
358 CAUTION: This is in function_obstack of the containing function. So
359 we must be sure that we never allocate from that obstack during
360 the compilation of a nested function if we expect it to survive past the
361 nested function's end. */
362 obstack_free (function_maybepermanent_obstack, maybepermanent_firstobj);
364 obstack_free (function_obstack, 0);
365 free (function_obstack);
367 momentary_firstobj = p->momentary_firstobj;
368 maybepermanent_firstobj = p->maybepermanent_firstobj;
369 function_obstack = p->function_obstack;
370 function_maybepermanent_obstack = p->function_maybepermanent_obstack;
371 current_obstack = p->current_obstack;
372 expression_obstack = p->expression_obstack;
373 saveable_obstack = p->saveable_obstack;
374 rtl_obstack = p->rtl_obstack;
377 /* Start allocating on the temporary (per function) obstack.
378 This is done in start_function before parsing the function body,
379 and before each initialization at top level, and to go back
380 to temporary allocation after doing permanent_allocation. */
383 temporary_allocation ()
385 /* Note that function_obstack at top level points to temporary_obstack.
386 But within a nested function context, it is a separate obstack. */
387 current_obstack = function_obstack;
388 expression_obstack = function_obstack;
389 rtl_obstack = saveable_obstack = function_maybepermanent_obstack;
393 /* Start allocating on the permanent obstack but don't
394 free the temporary data. After calling this, call
395 `permanent_allocation' to fully resume permanent allocation status. */
398 end_temporary_allocation ()
400 current_obstack = &permanent_obstack;
401 expression_obstack = &permanent_obstack;
402 rtl_obstack = saveable_obstack = &permanent_obstack;
405 /* Resume allocating on the temporary obstack, undoing
406 effects of `end_temporary_allocation'. */
409 resume_temporary_allocation ()
411 current_obstack = function_obstack;
412 expression_obstack = function_obstack;
413 rtl_obstack = saveable_obstack = function_maybepermanent_obstack;
416 /* While doing temporary allocation, switch to allocating in such a
417 way as to save all nodes if the function is inlined. Call
418 resume_temporary_allocation to go back to ordinary temporary
422 saveable_allocation ()
424 /* Note that function_obstack at top level points to temporary_obstack.
425 But within a nested function context, it is a separate obstack. */
426 expression_obstack = current_obstack = saveable_obstack;
429 /* Switch to current obstack CURRENT and maybepermanent obstack SAVEABLE,
430 recording the previously current obstacks on a stack.
431 This does not free any storage in any obstack. */
434 push_obstacks (current, saveable)
435 struct obstack *current, *saveable;
437 struct obstack_stack *p
438 = (struct obstack_stack *) obstack_alloc (&obstack_stack_obstack,
439 (sizeof (struct obstack_stack)));
441 p->current = current_obstack;
442 p->saveable = saveable_obstack;
443 p->expression = expression_obstack;
444 p->rtl = rtl_obstack;
445 p->next = obstack_stack;
448 current_obstack = current;
449 expression_obstack = current;
450 rtl_obstack = saveable_obstack = saveable;
453 /* Save the current set of obstacks, but don't change them. */
456 push_obstacks_nochange ()
458 struct obstack_stack *p
459 = (struct obstack_stack *) obstack_alloc (&obstack_stack_obstack,
460 (sizeof (struct obstack_stack)));
462 p->current = current_obstack;
463 p->saveable = saveable_obstack;
464 p->expression = expression_obstack;
465 p->rtl = rtl_obstack;
466 p->next = obstack_stack;
470 /* Pop the obstack selection stack. */
475 struct obstack_stack *p = obstack_stack;
476 obstack_stack = p->next;
478 current_obstack = p->current;
479 saveable_obstack = p->saveable;
480 expression_obstack = p->expression;
481 rtl_obstack = p->rtl;
483 obstack_free (&obstack_stack_obstack, p);
486 /* Nonzero if temporary allocation is currently in effect.
487 Zero if currently doing permanent allocation. */
490 allocation_temporary_p ()
492 return current_obstack != &permanent_obstack;
495 /* Go back to allocating on the permanent obstack
496 and free everything in the temporary obstack.
497 This is done in finish_function after fully compiling a function. */
500 permanent_allocation ()
502 /* Free up previous temporary obstack data */
503 obstack_free (&temporary_obstack, temporary_firstobj);
504 obstack_free (&momentary_obstack, momentary_firstobj);
505 obstack_free (&maybepermanent_obstack, maybepermanent_firstobj);
506 obstack_free (&temp_decl_obstack, temp_decl_firstobj);
508 current_obstack = &permanent_obstack;
509 expression_obstack = &permanent_obstack;
510 rtl_obstack = saveable_obstack = &permanent_obstack;
513 /* Save permanently everything on the maybepermanent_obstack. */
518 maybepermanent_firstobj
519 = (char *) obstack_alloc (function_maybepermanent_obstack, 0);
523 preserve_initializer ()
526 = (char *) obstack_alloc (&temporary_obstack, 0);
528 = (char *) obstack_alloc (&momentary_obstack, 0);
529 maybepermanent_firstobj
530 = (char *) obstack_alloc (function_maybepermanent_obstack, 0);
533 /* Start allocating new rtl in current_obstack.
534 Use resume_temporary_allocation
535 to go back to allocating rtl in saveable_obstack. */
538 rtl_in_current_obstack ()
540 rtl_obstack = current_obstack;
543 /* Start allocating rtl from saveable_obstack. Intended to be used after
544 a call to push_obstacks_nochange. */
547 rtl_in_saveable_obstack ()
549 rtl_obstack = saveable_obstack;
552 /* Allocate SIZE bytes in the current obstack
553 and return a pointer to them.
554 In practice the current obstack is always the temporary one. */
560 return (char *) obstack_alloc (current_obstack, size);
563 /* Free the object PTR in the current obstack
564 as well as everything allocated since PTR.
565 In practice the current obstack is always the temporary one. */
571 obstack_free (current_obstack, ptr);
574 /* Allocate SIZE bytes in the permanent obstack
575 and return a pointer to them. */
581 return (char *) obstack_alloc (&permanent_obstack, size);
584 /* Allocate NELEM items of SIZE bytes in the permanent obstack
585 and return a pointer to them. The storage is cleared before
586 returning the value. */
589 perm_calloc (nelem, size)
593 char *rval = (char *) obstack_alloc (&permanent_obstack, nelem * size);
594 bzero (rval, nelem * size);
598 /* Allocate SIZE bytes in the saveable obstack
599 and return a pointer to them. */
605 return (char *) obstack_alloc (saveable_obstack, size);
608 /* Print out which obstack an object is in. */
611 print_obstack_name (object, file, prefix)
616 struct obstack *obstack = NULL;
617 char *obstack_name = NULL;
620 for (p = outer_function_chain; p; p = p->next)
622 if (_obstack_allocated_p (p->function_obstack, object))
624 obstack = p->function_obstack;
625 obstack_name = "containing function obstack";
627 if (_obstack_allocated_p (p->function_maybepermanent_obstack, object))
629 obstack = p->function_maybepermanent_obstack;
630 obstack_name = "containing function maybepermanent obstack";
634 if (_obstack_allocated_p (&obstack_stack_obstack, object))
636 obstack = &obstack_stack_obstack;
637 obstack_name = "obstack_stack_obstack";
639 else if (_obstack_allocated_p (function_obstack, object))
641 obstack = function_obstack;
642 obstack_name = "function obstack";
644 else if (_obstack_allocated_p (&permanent_obstack, object))
646 obstack = &permanent_obstack;
647 obstack_name = "permanent_obstack";
649 else if (_obstack_allocated_p (&momentary_obstack, object))
651 obstack = &momentary_obstack;
652 obstack_name = "momentary_obstack";
654 else if (_obstack_allocated_p (function_maybepermanent_obstack, object))
656 obstack = function_maybepermanent_obstack;
657 obstack_name = "function maybepermanent obstack";
659 else if (_obstack_allocated_p (&temp_decl_obstack, object))
661 obstack = &temp_decl_obstack;
662 obstack_name = "temp_decl_obstack";
665 /* Check to see if the object is in the free area of the obstack. */
668 if (object >= obstack->next_free
669 && object < obstack->chunk_limit)
670 fprintf (file, "%s in free portion of obstack %s",
671 prefix, obstack_name);
673 fprintf (file, "%s allocated from %s", prefix, obstack_name);
676 fprintf (file, "%s not allocated from any obstack", prefix);
680 debug_obstack (object)
683 print_obstack_name (object, stderr, "object");
684 fprintf (stderr, ".\n");
687 /* Return 1 if OBJ is in the permanent obstack.
688 This is slow, and should be used only for debugging.
689 Use TREE_PERMANENT for other purposes. */
692 object_permanent_p (obj)
695 return _obstack_allocated_p (&permanent_obstack, obj);
698 /* Start a level of momentary allocation.
699 In C, each compound statement has its own level
700 and that level is freed at the end of each statement.
701 All expression nodes are allocated in the momentary allocation level. */
706 struct momentary_level *tem
707 = (struct momentary_level *) obstack_alloc (&momentary_obstack,
708 sizeof (struct momentary_level));
709 tem->prev = momentary_stack;
710 tem->base = (char *) obstack_base (&momentary_obstack);
711 tem->obstack = expression_obstack;
712 momentary_stack = tem;
713 expression_obstack = &momentary_obstack;
716 /* Free all the storage in the current momentary-allocation level.
717 In C, this happens at the end of each statement. */
722 obstack_free (&momentary_obstack, momentary_stack->base);
725 /* Discard a level of momentary allocation.
726 In C, this happens at the end of each compound statement.
727 Restore the status of expression node allocation
728 that was in effect before this level was created. */
733 struct momentary_level *tem = momentary_stack;
734 momentary_stack = tem->prev;
735 expression_obstack = tem->obstack;
736 obstack_free (&momentary_obstack, tem);
739 /* Pop back to the previous level of momentary allocation,
740 but don't free any momentary data just yet. */
743 pop_momentary_nofree ()
745 struct momentary_level *tem = momentary_stack;
746 momentary_stack = tem->prev;
747 expression_obstack = tem->obstack;
750 /* Call when starting to parse a declaration:
751 make expressions in the declaration last the length of the function.
752 Returns an argument that should be passed to resume_momentary later. */
757 register int tem = expression_obstack == &momentary_obstack;
758 expression_obstack = saveable_obstack;
762 /* Call when finished parsing a declaration:
763 restore the treatment of node-allocation that was
764 in effect before the suspension.
765 YES should be the value previously returned by suspend_momentary. */
768 resume_momentary (yes)
772 expression_obstack = &momentary_obstack;
775 /* Init the tables indexed by tree code.
776 Note that languages can add to these tables to define their own codes. */
781 tree_code_type = (char **) xmalloc (sizeof (standard_tree_code_type));
782 tree_code_length = (int *) xmalloc (sizeof (standard_tree_code_length));
783 tree_code_name = (char **) xmalloc (sizeof (standard_tree_code_name));
784 bcopy (standard_tree_code_type, tree_code_type,
785 sizeof (standard_tree_code_type));
786 bcopy (standard_tree_code_length, tree_code_length,
787 sizeof (standard_tree_code_length));
788 bcopy (standard_tree_code_name, tree_code_name,
789 sizeof (standard_tree_code_name));
792 /* Return a newly allocated node of code CODE.
793 Initialize the node's unique id and its TREE_PERMANENT flag.
794 For decl and type nodes, some other fields are initialized.
795 The rest of the node is initialized to zero.
797 Achoo! I got a code in the node. */
804 register int type = TREE_CODE_CLASS (code);
806 register struct obstack *obstack = current_obstack;
808 register tree_node_kind kind;
812 case 'd': /* A decl node */
813 #ifdef GATHER_STATISTICS
816 length = sizeof (struct tree_decl);
817 /* All decls in an inline function need to be saved. */
818 if (obstack != &permanent_obstack)
819 obstack = saveable_obstack;
821 /* PARM_DECLs go on the context of the parent. If this is a nested
822 function, then we must allocate the PARM_DECL on the parent's
823 obstack, so that they will live to the end of the parent's
824 closing brace. This is neccesary in case we try to inline the
825 function into its parent.
827 PARM_DECLs of top-level functions do not have this problem. However,
828 we allocate them where we put the FUNCTION_DECL for languauges such as
829 Ada that need to consult some flags in the PARM_DECLs of the function
832 See comment in restore_tree_status for why we can't put this
833 in function_obstack. */
834 if (code == PARM_DECL && obstack != &permanent_obstack)
837 if (current_function_decl)
838 context = decl_function_context (current_function_decl);
842 = find_function_data (context)->function_maybepermanent_obstack;
846 case 't': /* a type node */
847 #ifdef GATHER_STATISTICS
850 length = sizeof (struct tree_type);
851 /* All data types are put where we can preserve them if nec. */
852 if (obstack != &permanent_obstack)
853 obstack = all_types_permanent ? &permanent_obstack : saveable_obstack;
856 case 'b': /* a lexical block */
857 #ifdef GATHER_STATISTICS
860 length = sizeof (struct tree_block);
861 /* All BLOCK nodes are put where we can preserve them if nec. */
862 if (obstack != &permanent_obstack)
863 obstack = saveable_obstack;
866 case 's': /* an expression with side effects */
867 #ifdef GATHER_STATISTICS
871 case 'r': /* a reference */
872 #ifdef GATHER_STATISTICS
876 case 'e': /* an expression */
877 case '<': /* a comparison expression */
878 case '1': /* a unary arithmetic expression */
879 case '2': /* a binary arithmetic expression */
880 #ifdef GATHER_STATISTICS
884 obstack = expression_obstack;
885 /* All BIND_EXPR nodes are put where we can preserve them if nec. */
886 if (code == BIND_EXPR && obstack != &permanent_obstack)
887 obstack = saveable_obstack;
888 length = sizeof (struct tree_exp)
889 + (tree_code_length[(int) code] - 1) * sizeof (char *);
892 case 'c': /* a constant */
893 #ifdef GATHER_STATISTICS
896 obstack = expression_obstack;
898 /* We can't use tree_code_length for INTEGER_CST, since the number of
899 words is machine-dependent due to varying length of HOST_WIDE_INT,
900 which might be wider than a pointer (e.g., long long). Similarly
901 for REAL_CST, since the number of words is machine-dependent due
902 to varying size and alignment of `double'. */
904 if (code == INTEGER_CST)
905 length = sizeof (struct tree_int_cst);
906 else if (code == REAL_CST)
907 length = sizeof (struct tree_real_cst);
909 length = sizeof (struct tree_common)
910 + tree_code_length[(int) code] * sizeof (char *);
913 case 'x': /* something random, like an identifier. */
914 #ifdef GATHER_STATISTICS
915 if (code == IDENTIFIER_NODE)
917 else if (code == OP_IDENTIFIER)
919 else if (code == TREE_VEC)
924 length = sizeof (struct tree_common)
925 + tree_code_length[(int) code] * sizeof (char *);
926 /* Identifier nodes are always permanent since they are
927 unique in a compiler run. */
928 if (code == IDENTIFIER_NODE) obstack = &permanent_obstack;
931 t = (tree) obstack_alloc (obstack, length);
933 #ifdef GATHER_STATISTICS
934 tree_node_counts[(int)kind]++;
935 tree_node_sizes[(int)kind] += length;
938 /* Clear a word at a time. */
939 for (i = (length / sizeof (int)) - 1; i >= 0; i--)
941 /* Clear any extra bytes. */
942 for (i = length / sizeof (int) * sizeof (int); i < length; i++)
945 TREE_SET_CODE (t, code);
946 if (obstack == &permanent_obstack)
947 TREE_PERMANENT (t) = 1;
952 TREE_SIDE_EFFECTS (t) = 1;
953 TREE_TYPE (t) = void_type_node;
957 if (code != FUNCTION_DECL)
959 DECL_IN_SYSTEM_HEADER (t)
960 = in_system_header && (obstack == &permanent_obstack);
961 DECL_SOURCE_LINE (t) = lineno;
962 DECL_SOURCE_FILE (t) = (input_filename) ? input_filename : "<built-in>";
963 DECL_UID (t) = next_decl_uid++;
967 TYPE_UID (t) = next_type_uid++;
969 TYPE_MAIN_VARIANT (t) = t;
970 TYPE_OBSTACK (t) = obstack;
974 TREE_CONSTANT (t) = 1;
981 /* Return a new node with the same contents as NODE
982 except that its TREE_CHAIN is zero and it has a fresh uid. */
989 register enum tree_code code = TREE_CODE (node);
993 switch (TREE_CODE_CLASS (code))
995 case 'd': /* A decl node */
996 length = sizeof (struct tree_decl);
999 case 't': /* a type node */
1000 length = sizeof (struct tree_type);
1003 case 'b': /* a lexical block node */
1004 length = sizeof (struct tree_block);
1007 case 'r': /* a reference */
1008 case 'e': /* an expression */
1009 case 's': /* an expression with side effects */
1010 case '<': /* a comparison expression */
1011 case '1': /* a unary arithmetic expression */
1012 case '2': /* a binary arithmetic expression */
1013 length = sizeof (struct tree_exp)
1014 + (tree_code_length[(int) code] - 1) * sizeof (char *);
1017 case 'c': /* a constant */
1018 /* We can't use tree_code_length for INTEGER_CST, since the number of
1019 words is machine-dependent due to varying length of HOST_WIDE_INT,
1020 which might be wider than a pointer (e.g., long long). Similarly
1021 for REAL_CST, since the number of words is machine-dependent due
1022 to varying size and alignment of `double'. */
1023 if (code == INTEGER_CST)
1025 length = sizeof (struct tree_int_cst);
1028 else if (code == REAL_CST)
1030 length = sizeof (struct tree_real_cst);
1034 case 'x': /* something random, like an identifier. */
1035 length = sizeof (struct tree_common)
1036 + tree_code_length[(int) code] * sizeof (char *);
1037 if (code == TREE_VEC)
1038 length += (TREE_VEC_LENGTH (node) - 1) * sizeof (char *);
1041 t = (tree) obstack_alloc (current_obstack, length);
1043 for (i = (length / sizeof (int)) - 1; i >= 0; i--)
1044 ((int *) t)[i] = ((int *) node)[i];
1045 /* Clear any extra bytes. */
1046 for (i = length / sizeof (int) * sizeof (int); i < length; i++)
1047 ((char *) t)[i] = ((char *) node)[i];
1051 if (TREE_CODE_CLASS (code) == 'd')
1052 DECL_UID (t) = next_decl_uid++;
1053 else if (TREE_CODE_CLASS (code) == 't')
1055 TYPE_UID (t) = next_type_uid++;
1056 TYPE_OBSTACK (t) = current_obstack;
1059 TREE_PERMANENT (t) = (current_obstack == &permanent_obstack);
1064 /* Return a copy of a chain of nodes, chained through the TREE_CHAIN field.
1065 For example, this can copy a list made of TREE_LIST nodes. */
1072 register tree prev, next;
1077 head = prev = copy_node (list);
1078 next = TREE_CHAIN (list);
1081 TREE_CHAIN (prev) = copy_node (next);
1082 prev = TREE_CHAIN (prev);
1083 next = TREE_CHAIN (next);
1090 /* Return an IDENTIFIER_NODE whose name is TEXT (a null-terminated string).
1091 If an identifier with that name has previously been referred to,
1092 the same node is returned this time. */
1095 get_identifier (text)
1096 register char *text;
1101 register int len, hash_len;
1103 /* Compute length of text in len. */
1104 for (len = 0; text[len]; len++);
1106 /* Decide how much of that length to hash on */
1108 if (warn_id_clash && len > id_clash_len)
1109 hash_len = id_clash_len;
1111 /* Compute hash code */
1112 hi = hash_len * 613 + (unsigned)text[0];
1113 for (i = 1; i < hash_len; i += 2)
1114 hi = ((hi * 613) + (unsigned)(text[i]));
1116 hi &= (1 << HASHBITS) - 1;
1117 hi %= MAX_HASH_TABLE;
1119 /* Search table for identifier */
1120 for (idp = hash_table[hi]; idp; idp = TREE_CHAIN (idp))
1121 if (IDENTIFIER_LENGTH (idp) == len
1122 && IDENTIFIER_POINTER (idp)[0] == text[0]
1123 && !bcmp (IDENTIFIER_POINTER (idp), text, len))
1124 return idp; /* <-- return if found */
1126 /* Not found; optionally warn about a similar identifier */
1127 if (warn_id_clash && do_identifier_warnings && len >= id_clash_len)
1128 for (idp = hash_table[hi]; idp; idp = TREE_CHAIN (idp))
1129 if (!strncmp (IDENTIFIER_POINTER (idp), text, id_clash_len))
1131 warning ("`%s' and `%s' identical in first %d characters",
1132 IDENTIFIER_POINTER (idp), text, id_clash_len);
1136 if (tree_code_length[(int) IDENTIFIER_NODE] < 0)
1137 abort (); /* set_identifier_size hasn't been called. */
1139 /* Not found, create one, add to chain */
1140 idp = make_node (IDENTIFIER_NODE);
1141 IDENTIFIER_LENGTH (idp) = len;
1142 #ifdef GATHER_STATISTICS
1143 id_string_size += len;
1146 IDENTIFIER_POINTER (idp) = obstack_copy0 (&permanent_obstack, text, len);
1148 TREE_CHAIN (idp) = hash_table[hi];
1149 hash_table[hi] = idp;
1150 return idp; /* <-- return if created */
1153 /* Enable warnings on similar identifiers (if requested).
1154 Done after the built-in identifiers are created. */
1157 start_identifier_warnings ()
1159 do_identifier_warnings = 1;
1162 /* Record the size of an identifier node for the language in use.
1163 SIZE is the total size in bytes.
1164 This is called by the language-specific files. This must be
1165 called before allocating any identifiers. */
1168 set_identifier_size (size)
1171 tree_code_length[(int) IDENTIFIER_NODE]
1172 = (size - sizeof (struct tree_common)) / sizeof (tree);
1175 /* Return a newly constructed INTEGER_CST node whose constant value
1176 is specified by the two ints LOW and HI.
1177 The TREE_TYPE is set to `int'.
1179 This function should be used via the `build_int_2' macro. */
1182 build_int_2_wide (low, hi)
1183 HOST_WIDE_INT low, hi;
1185 register tree t = make_node (INTEGER_CST);
1186 TREE_INT_CST_LOW (t) = low;
1187 TREE_INT_CST_HIGH (t) = hi;
1188 TREE_TYPE (t) = integer_type_node;
1192 /* Return a new REAL_CST node whose type is TYPE and value is D. */
1195 build_real (type, d)
1201 /* Check for valid float value for this type on this target machine;
1202 if not, can print error message and store a valid value in D. */
1203 #ifdef CHECK_FLOAT_VALUE
1204 CHECK_FLOAT_VALUE (TYPE_MODE (type), d);
1207 v = make_node (REAL_CST);
1208 TREE_TYPE (v) = type;
1209 TREE_REAL_CST (v) = d;
1213 /* Return a new REAL_CST node whose type is TYPE
1214 and whose value is the integer value of the INTEGER_CST node I. */
1216 #if !defined (REAL_IS_NOT_DOUBLE) || defined (REAL_ARITHMETIC)
1219 real_value_from_int_cst (i)
1224 /* Some 386 compilers mishandle unsigned int to float conversions,
1225 so introduce a temporary variable E to avoid those bugs. */
1227 #ifdef REAL_ARITHMETIC
1228 if (! TREE_UNSIGNED (TREE_TYPE (i)))
1229 REAL_VALUE_FROM_INT (d, TREE_INT_CST_LOW (i), TREE_INT_CST_HIGH (i));
1231 REAL_VALUE_FROM_UNSIGNED_INT (d, TREE_INT_CST_LOW (i), TREE_INT_CST_HIGH (i));
1232 #else /* not REAL_ARITHMETIC */
1233 if (TREE_INT_CST_HIGH (i) < 0 && ! TREE_UNSIGNED (TREE_TYPE (i)))
1235 d = (double) (~ TREE_INT_CST_HIGH (i));
1236 e = ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
1237 * (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
1239 e = (double) (unsigned HOST_WIDE_INT) (~ TREE_INT_CST_LOW (i));
1245 d = (double) (unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (i);
1246 e = ((double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2))
1247 * (double) ((HOST_WIDE_INT) 1 << (HOST_BITS_PER_WIDE_INT / 2)));
1249 e = (double) (unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (i);
1252 #endif /* not REAL_ARITHMETIC */
1256 /* This function can't be implemented if we can't do arithmetic
1257 on the float representation. */
1260 build_real_from_int_cst (type, i)
1267 v = make_node (REAL_CST);
1268 TREE_TYPE (v) = type;
1270 d = REAL_VALUE_TRUNCATE (TYPE_MODE (type), real_value_from_int_cst (i));
1271 /* Check for valid float value for this type on this target machine;
1272 if not, can print error message and store a valid value in D. */
1273 #ifdef CHECK_FLOAT_VALUE
1274 CHECK_FLOAT_VALUE (TYPE_MODE (type), d);
1277 TREE_REAL_CST (v) = d;
1281 #endif /* not REAL_IS_NOT_DOUBLE, or REAL_ARITHMETIC */
1283 /* Return a newly constructed STRING_CST node whose value is
1284 the LEN characters at STR.
1285 The TREE_TYPE is not initialized. */
1288 build_string (len, str)
1292 /* Put the string in saveable_obstack since it will be placed in the RTL
1293 for an "asm" statement and will also be kept around a while if
1294 deferring constant output in varasm.c. */
1296 register tree s = make_node (STRING_CST);
1297 TREE_STRING_LENGTH (s) = len;
1298 TREE_STRING_POINTER (s) = obstack_copy0 (saveable_obstack, str, len);
1302 /* Return a newly constructed COMPLEX_CST node whose value is
1303 specified by the real and imaginary parts REAL and IMAG.
1304 Both REAL and IMAG should be constant nodes.
1305 The TREE_TYPE is not initialized. */
1308 build_complex (real, imag)
1311 register tree t = make_node (COMPLEX_CST);
1312 TREE_REALPART (t) = real;
1313 TREE_IMAGPART (t) = imag;
1314 TREE_TYPE (t) = build_complex_type (TREE_TYPE (real));
1318 /* Build a newly constructed TREE_VEC node of length LEN. */
1324 register int length = (len-1) * sizeof (tree) + sizeof (struct tree_vec);
1325 register struct obstack *obstack = current_obstack;
1328 #ifdef GATHER_STATISTICS
1329 tree_node_counts[(int)vec_kind]++;
1330 tree_node_sizes[(int)vec_kind] += length;
1333 t = (tree) obstack_alloc (obstack, length);
1335 for (i = (length / sizeof (int)) - 1; i >= 0; i--)
1338 TREE_SET_CODE (t, TREE_VEC);
1339 TREE_VEC_LENGTH (t) = len;
1340 if (obstack == &permanent_obstack)
1341 TREE_PERMANENT (t) = 1;
1346 /* Return 1 if EXPR is the integer constant zero. */
1349 integer_zerop (expr)
1354 return (TREE_CODE (expr) == INTEGER_CST
1355 && TREE_INT_CST_LOW (expr) == 0
1356 && TREE_INT_CST_HIGH (expr) == 0);
1359 /* Return 1 if EXPR is the integer constant one. */
1367 return (TREE_CODE (expr) == INTEGER_CST
1368 && TREE_INT_CST_LOW (expr) == 1
1369 && TREE_INT_CST_HIGH (expr) == 0);
1372 /* Return 1 if EXPR is an integer containing all 1's
1373 in as much precision as it contains. */
1376 integer_all_onesp (expr)
1384 if (TREE_CODE (expr) != INTEGER_CST)
1387 uns = TREE_UNSIGNED (TREE_TYPE (expr));
1389 return TREE_INT_CST_LOW (expr) == -1 && TREE_INT_CST_HIGH (expr) == -1;
1391 prec = TYPE_PRECISION (TREE_TYPE (expr));
1392 if (prec >= HOST_BITS_PER_WIDE_INT)
1394 int high_value, shift_amount;
1396 shift_amount = prec - HOST_BITS_PER_WIDE_INT;
1398 if (shift_amount > HOST_BITS_PER_WIDE_INT)
1399 /* Can not handle precisions greater than twice the host int size. */
1401 else if (shift_amount == HOST_BITS_PER_WIDE_INT)
1402 /* Shifting by the host word size is undefined according to the ANSI
1403 standard, so we must handle this as a special case. */
1406 high_value = ((HOST_WIDE_INT) 1 << shift_amount) - 1;
1408 return TREE_INT_CST_LOW (expr) == -1
1409 && TREE_INT_CST_HIGH (expr) == high_value;
1412 return TREE_INT_CST_LOW (expr) == ((HOST_WIDE_INT) 1 << prec) - 1;
1415 /* Return 1 if EXPR is an integer constant that is a power of 2 (i.e., has only
1419 integer_pow2p (expr)
1422 HOST_WIDE_INT high, low;
1426 if (TREE_CODE (expr) != INTEGER_CST)
1429 high = TREE_INT_CST_HIGH (expr);
1430 low = TREE_INT_CST_LOW (expr);
1432 if (high == 0 && low == 0)
1435 return ((high == 0 && (low & (low - 1)) == 0)
1436 || (low == 0 && (high & (high - 1)) == 0));
1439 /* Return 1 if EXPR is the real constant zero. */
1447 return (TREE_CODE (expr) == REAL_CST
1448 && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst0));
1451 /* Return 1 if EXPR is the real constant one. */
1459 return (TREE_CODE (expr) == REAL_CST
1460 && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst1));
1463 /* Return 1 if EXPR is the real constant two. */
1471 return (TREE_CODE (expr) == REAL_CST
1472 && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst2));
1475 /* Nonzero if EXP is a constant or a cast of a constant. */
1478 really_constant_p (exp)
1481 /* This is not quite the same as STRIP_NOPS. It does more. */
1482 while (TREE_CODE (exp) == NOP_EXPR
1483 || TREE_CODE (exp) == CONVERT_EXPR
1484 || TREE_CODE (exp) == NON_LVALUE_EXPR)
1485 exp = TREE_OPERAND (exp, 0);
1486 return TREE_CONSTANT (exp);
1489 /* Return first list element whose TREE_VALUE is ELEM.
1490 Return 0 if ELEM is not it LIST. */
1493 value_member (elem, list)
1498 if (elem == TREE_VALUE (list))
1500 list = TREE_CHAIN (list);
1505 /* Return first list element whose TREE_PURPOSE is ELEM.
1506 Return 0 if ELEM is not it LIST. */
1509 purpose_member (elem, list)
1514 if (elem == TREE_PURPOSE (list))
1516 list = TREE_CHAIN (list);
1521 /* Return first list element whose BINFO_TYPE is ELEM.
1522 Return 0 if ELEM is not it LIST. */
1525 binfo_member (elem, list)
1530 if (elem == BINFO_TYPE (list))
1532 list = TREE_CHAIN (list);
1537 /* Return nonzero if ELEM is part of the chain CHAIN. */
1540 chain_member (elem, chain)
1547 chain = TREE_CHAIN (chain);
1553 /* Return the length of a chain of nodes chained through TREE_CHAIN.
1554 We expect a null pointer to mark the end of the chain.
1555 This is the Lisp primitive `length'. */
1562 register int len = 0;
1564 for (tail = t; tail; tail = TREE_CHAIN (tail))
1570 /* Concatenate two chains of nodes (chained through TREE_CHAIN)
1571 by modifying the last node in chain 1 to point to chain 2.
1572 This is the Lisp primitive `nconc'. */
1584 for (t1 = op1; TREE_CHAIN (t1); t1 = TREE_CHAIN (t1))
1586 TREE_CHAIN (t1) = op2;
1587 for (t2 = op2; t2; t2 = TREE_CHAIN (t2))
1589 abort (); /* Circularity created. */
1595 /* Return the last node in a chain of nodes (chained through TREE_CHAIN). */
1599 register tree chain;
1603 while (next = TREE_CHAIN (chain))
1608 /* Reverse the order of elements in the chain T,
1609 and return the new head of the chain (old last element). */
1615 register tree prev = 0, decl, next;
1616 for (decl = t; decl; decl = next)
1618 next = TREE_CHAIN (decl);
1619 TREE_CHAIN (decl) = prev;
1625 /* Given a chain CHAIN of tree nodes,
1626 construct and return a list of those nodes. */
1632 tree result = NULL_TREE;
1633 tree in_tail = chain;
1634 tree out_tail = NULL_TREE;
1638 tree next = tree_cons (NULL_TREE, in_tail, NULL_TREE);
1640 TREE_CHAIN (out_tail) = next;
1644 in_tail = TREE_CHAIN (in_tail);
1650 /* Return a newly created TREE_LIST node whose
1651 purpose and value fields are PARM and VALUE. */
1654 build_tree_list (parm, value)
1657 register tree t = make_node (TREE_LIST);
1658 TREE_PURPOSE (t) = parm;
1659 TREE_VALUE (t) = value;
1663 /* Similar, but build on the temp_decl_obstack. */
1666 build_decl_list (parm, value)
1670 register struct obstack *ambient_obstack = current_obstack;
1671 current_obstack = &temp_decl_obstack;
1672 node = build_tree_list (parm, value);
1673 current_obstack = ambient_obstack;
1677 /* Return a newly created TREE_LIST node whose
1678 purpose and value fields are PARM and VALUE
1679 and whose TREE_CHAIN is CHAIN. */
1682 tree_cons (purpose, value, chain)
1683 tree purpose, value, chain;
1686 register tree node = make_node (TREE_LIST);
1689 register tree node = (tree) obstack_alloc (current_obstack, sizeof (struct tree_list));
1690 #ifdef GATHER_STATISTICS
1691 tree_node_counts[(int)x_kind]++;
1692 tree_node_sizes[(int)x_kind] += sizeof (struct tree_list);
1695 for (i = (sizeof (struct tree_common) / sizeof (int)) - 1; i >= 0; i--)
1696 ((int *) node)[i] = 0;
1698 TREE_SET_CODE (node, TREE_LIST);
1699 if (current_obstack == &permanent_obstack)
1700 TREE_PERMANENT (node) = 1;
1703 TREE_CHAIN (node) = chain;
1704 TREE_PURPOSE (node) = purpose;
1705 TREE_VALUE (node) = value;
1709 /* Similar, but build on the temp_decl_obstack. */
1712 decl_tree_cons (purpose, value, chain)
1713 tree purpose, value, chain;
1716 register struct obstack *ambient_obstack = current_obstack;
1717 current_obstack = &temp_decl_obstack;
1718 node = tree_cons (purpose, value, chain);
1719 current_obstack = ambient_obstack;
1723 /* Same as `tree_cons' but make a permanent object. */
1726 perm_tree_cons (purpose, value, chain)
1727 tree purpose, value, chain;
1730 register struct obstack *ambient_obstack = current_obstack;
1731 current_obstack = &permanent_obstack;
1733 node = tree_cons (purpose, value, chain);
1734 current_obstack = ambient_obstack;
1738 /* Same as `tree_cons', but make this node temporary, regardless. */
1741 temp_tree_cons (purpose, value, chain)
1742 tree purpose, value, chain;
1745 register struct obstack *ambient_obstack = current_obstack;
1746 current_obstack = &temporary_obstack;
1748 node = tree_cons (purpose, value, chain);
1749 current_obstack = ambient_obstack;
1753 /* Same as `tree_cons', but save this node if the function's RTL is saved. */
1756 saveable_tree_cons (purpose, value, chain)
1757 tree purpose, value, chain;
1760 register struct obstack *ambient_obstack = current_obstack;
1761 current_obstack = saveable_obstack;
1763 node = tree_cons (purpose, value, chain);
1764 current_obstack = ambient_obstack;
1768 /* Return the size nominally occupied by an object of type TYPE
1769 when it resides in memory. The value is measured in units of bytes,
1770 and its data type is that normally used for type sizes
1771 (which is the first type created by make_signed_type or
1772 make_unsigned_type). */
1775 size_in_bytes (type)
1780 if (type == error_mark_node)
1781 return integer_zero_node;
1782 type = TYPE_MAIN_VARIANT (type);
1783 if (TYPE_SIZE (type) == 0)
1785 incomplete_type_error (NULL_TREE, type);
1786 return integer_zero_node;
1788 t = size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type),
1789 size_int (BITS_PER_UNIT));
1790 if (TREE_CODE (t) == INTEGER_CST)
1791 force_fit_type (t, 0);
1795 /* Return the size of TYPE (in bytes) as an integer,
1796 or return -1 if the size can vary. */
1799 int_size_in_bytes (type)
1803 if (type == error_mark_node)
1805 type = TYPE_MAIN_VARIANT (type);
1806 if (TYPE_SIZE (type) == 0)
1808 if (TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1810 if (TREE_INT_CST_HIGH (TYPE_SIZE (type)) != 0)
1812 tree t = size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type),
1813 size_int (BITS_PER_UNIT));
1814 return TREE_INT_CST_LOW (t);
1816 size = TREE_INT_CST_LOW (TYPE_SIZE (type));
1817 return (size + BITS_PER_UNIT - 1) / BITS_PER_UNIT;
1820 /* Return, as a tree node, the number of elements for TYPE (which is an
1821 ARRAY_TYPE) minus one. This counts only elements of the top array. */
1824 array_type_nelts (type)
1827 tree index_type = TYPE_DOMAIN (type);
1829 return (integer_zerop (TYPE_MIN_VALUE (index_type))
1830 ? TYPE_MAX_VALUE (index_type)
1831 : fold (build (MINUS_EXPR, TREE_TYPE (TYPE_MAX_VALUE (index_type)),
1832 TYPE_MAX_VALUE (index_type),
1833 TYPE_MIN_VALUE (index_type))));
1836 /* Return nonzero if arg is static -- a reference to an object in
1837 static storage. This is not the same as the C meaning of `static'. */
1843 switch (TREE_CODE (arg))
1847 return TREE_STATIC (arg) || DECL_EXTERNAL (arg);
1850 return TREE_STATIC (arg);
1857 return staticp (TREE_OPERAND (arg, 0));
1860 return TREE_CONSTANT (TREE_OPERAND (arg, 0));
1863 if (TREE_CODE (TYPE_SIZE (TREE_TYPE (arg))) == INTEGER_CST
1864 && TREE_CODE (TREE_OPERAND (arg, 1)) == INTEGER_CST)
1865 return staticp (TREE_OPERAND (arg, 0));
1871 /* Wrap a SAVE_EXPR around EXPR, if appropriate.
1872 Do this to any expression which may be used in more than one place,
1873 but must be evaluated only once.
1875 Normally, expand_expr would reevaluate the expression each time.
1876 Calling save_expr produces something that is evaluated and recorded
1877 the first time expand_expr is called on it. Subsequent calls to
1878 expand_expr just reuse the recorded value.
1880 The call to expand_expr that generates code that actually computes
1881 the value is the first call *at compile time*. Subsequent calls
1882 *at compile time* generate code to use the saved value.
1883 This produces correct result provided that *at run time* control
1884 always flows through the insns made by the first expand_expr
1885 before reaching the other places where the save_expr was evaluated.
1886 You, the caller of save_expr, must make sure this is so.
1888 Constants, and certain read-only nodes, are returned with no
1889 SAVE_EXPR because that is safe. Expressions containing placeholders
1890 are not touched; see tree.def for an explanation of what these
1897 register tree t = fold (expr);
1899 /* We don't care about whether this can be used as an lvalue in this
1901 while (TREE_CODE (t) == NON_LVALUE_EXPR)
1902 t = TREE_OPERAND (t, 0);
1904 /* If the tree evaluates to a constant, then we don't want to hide that
1905 fact (i.e. this allows further folding, and direct checks for constants).
1906 However, a read-only object that has side effects cannot be bypassed.
1907 Since it is no problem to reevaluate literals, we just return the
1910 if (TREE_CONSTANT (t) || (TREE_READONLY (t) && ! TREE_SIDE_EFFECTS (t))
1911 || TREE_CODE (t) == SAVE_EXPR)
1914 /* If T contains a PLACEHOLDER_EXPR, we must evaluate it each time, since
1915 it means that the size or offset of some field of an object depends on
1916 the value within another field.
1918 Note that it must not be the case that T contains both a PLACEHOLDER_EXPR
1919 and some variable since it would then need to be both evaluated once and
1920 evaluated more than once. Front-ends must assure this case cannot
1921 happen by surrounding any such subexpressions in their own SAVE_EXPR
1922 and forcing evaluation at the proper time. */
1923 if (contains_placeholder_p (t))
1926 t = build (SAVE_EXPR, TREE_TYPE (expr), t, current_function_decl, NULL_TREE);
1928 /* This expression might be placed ahead of a jump to ensure that the
1929 value was computed on both sides of the jump. So make sure it isn't
1930 eliminated as dead. */
1931 TREE_SIDE_EFFECTS (t) = 1;
1935 /* Return 1 if EXP contains a PLACEHOLDER_EXPR; i.e., if it represents a size
1936 or offset that depends on a field within a record.
1938 Note that we only allow such expressions within simple arithmetic
1942 contains_placeholder_p (exp)
1945 register enum tree_code code = TREE_CODE (exp);
1948 /* If we have a WITH_RECORD_EXPR, it "cancels" any PLACEHOLDER_EXPR
1949 in it since it is supplying a value for it. */
1950 if (code == WITH_RECORD_EXPR)
1953 switch (TREE_CODE_CLASS (code))
1956 for (inner = TREE_OPERAND (exp, 0);
1957 TREE_CODE_CLASS (TREE_CODE (inner)) == 'r';
1958 inner = TREE_OPERAND (inner, 0))
1960 return TREE_CODE (inner) == PLACEHOLDER_EXPR;
1965 switch (tree_code_length[(int) code])
1968 return contains_placeholder_p (TREE_OPERAND (exp, 0));
1970 return (code != RTL_EXPR
1971 && code != CONSTRUCTOR
1972 && ! (code == SAVE_EXPR && SAVE_EXPR_RTL (exp) != 0)
1973 && code != WITH_RECORD_EXPR
1974 && (contains_placeholder_p (TREE_OPERAND (exp, 0))
1975 || contains_placeholder_p (TREE_OPERAND (exp, 1))));
1977 return (code == COND_EXPR
1978 && (contains_placeholder_p (TREE_OPERAND (exp, 0))
1979 || contains_placeholder_p (TREE_OPERAND (exp, 1))
1980 || contains_placeholder_p (TREE_OPERAND (exp, 2))));
1987 /* Given a tree EXP, a FIELD_DECL F, and a replacement value R,
1988 return a tree with all occurrences of references to F in a
1989 PLACEHOLDER_EXPR replaced by R. Note that we assume here that EXP
1990 contains only arithmetic expressions. */
1993 substitute_in_expr (exp, f, r)
1998 enum tree_code code = TREE_CODE (exp);
2001 switch (TREE_CODE_CLASS (code))
2008 if (code == PLACEHOLDER_EXPR)
2016 switch (tree_code_length[(int) code])
2019 return fold (build1 (code, TREE_TYPE (exp),
2020 substitute_in_expr (TREE_OPERAND (exp, 0),
2024 /* An RTL_EXPR cannot contain a PLACEHOLDER_EXPR; a CONSTRUCTOR
2025 could, but we don't support it. */
2026 if (code == RTL_EXPR)
2028 else if (code == CONSTRUCTOR)
2031 return fold (build (code, TREE_TYPE (exp),
2032 substitute_in_expr (TREE_OPERAND (exp, 0), f, r),
2033 substitute_in_expr (TREE_OPERAND (exp, 1),
2037 /* It cannot be that anything inside a SAVE_EXPR contains a
2038 PLACEHOLDER_EXPR. */
2039 if (code == SAVE_EXPR)
2042 if (code != COND_EXPR)
2045 return fold (build (code, TREE_TYPE (exp),
2046 substitute_in_expr (TREE_OPERAND (exp, 0), f, r),
2047 substitute_in_expr (TREE_OPERAND (exp, 1), f, r),
2048 substitute_in_expr (TREE_OPERAND (exp, 2),
2058 /* If this expression is getting a value from a PLACEHOLDER_EXPR
2059 and it is the right field, replace it with R. */
2060 for (inner = TREE_OPERAND (exp, 0);
2061 TREE_CODE_CLASS (TREE_CODE (inner)) == 'r';
2062 inner = TREE_OPERAND (inner, 0))
2064 if (TREE_CODE (inner) == PLACEHOLDER_EXPR
2065 && TREE_OPERAND (exp, 1) == f)
2068 return fold (build (code, TREE_TYPE (exp),
2069 substitute_in_expr (TREE_OPERAND (exp, 0), f, r),
2070 TREE_OPERAND (exp, 1)));
2072 return fold (build (code, TREE_TYPE (exp),
2073 substitute_in_expr (TREE_OPERAND (exp, 0), f, r),
2074 substitute_in_expr (TREE_OPERAND (exp, 1), f, r),
2075 substitute_in_expr (TREE_OPERAND (exp, 2), f, r)));
2078 return fold (build1 (code, TREE_TYPE (exp),
2079 substitute_in_expr (TREE_OPERAND (exp, 0),
2082 return fold (build (code, TREE_TYPE (exp),
2083 substitute_in_expr (TREE_OPERAND (exp, 0), f, r),
2084 substitute_in_expr (TREE_OPERAND (exp, 1), f, r)));
2088 /* If it wasn't one of the cases we handle, give up. */
2093 /* Given a type T, a FIELD_DECL F, and a replacement value R,
2094 return a new type with all size expressions that contain F
2095 updated by replacing F with R. */
2098 substitute_in_type (t, f, r)
2101 switch (TREE_CODE (t))
2110 if ((TREE_CODE (TYPE_MIN_VALUE (t)) != INTEGER_CST
2111 && contains_placeholder_p (TYPE_MIN_VALUE (t)))
2112 || (TREE_CODE (TYPE_MAX_VALUE (t)) != INTEGER_CST
2113 && contains_placeholder_p (TYPE_MAX_VALUE (t))))
2114 return build_range_type (t,
2115 substitute_in_expr (TYPE_MIN_VALUE (t), f, r),
2116 substitute_in_expr (TYPE_MAX_VALUE (t), f, r));
2120 if ((TREE_CODE (TYPE_MIN_VALUE (t)) != INTEGER_CST
2121 && contains_placeholder_p (TYPE_MIN_VALUE (t)))
2122 || (TREE_CODE (TYPE_MAX_VALUE (t)) != INTEGER_CST
2123 && contains_placeholder_p (TYPE_MAX_VALUE (t))))
2125 t = build_type_copy (t);
2126 TYPE_MIN_VALUE (t) = substitute_in_expr (TYPE_MIN_VALUE (t), f, r);
2127 TYPE_MAX_VALUE (t) = substitute_in_expr (TYPE_MAX_VALUE (t), f, r);
2132 return build_complex_type (substitute_in_type (TREE_TYPE (t), f, r));
2136 case REFERENCE_TYPE:
2142 /* Don't know how to do these yet. */
2146 t = build_array_type (substitute_in_type (TREE_TYPE (t), f, r),
2147 substitute_in_type (TYPE_DOMAIN (t), f, r));
2154 case QUAL_UNION_TYPE:
2156 tree new = copy_node (t);
2158 tree last_field = 0;
2160 /* Start out with no fields, make new fields, and chain them
2163 TYPE_FIELDS (new) = 0;
2164 TYPE_SIZE (new) = 0;
2166 for (field = TYPE_FIELDS (t); field;
2167 field = TREE_CHAIN (field))
2169 tree new_field = copy_node (field);
2171 TREE_TYPE (new_field)
2172 = substitute_in_type (TREE_TYPE (new_field), f, r);
2174 /* If this is an anonymous field and the type of this field is
2175 a UNION_TYPE or RECORD_TYPE with no elements, ignore it. If
2176 the type just has one element, treat that as the field.
2177 But don't do this if we are processing a QUAL_UNION_TYPE. */
2178 if (TREE_CODE (t) != QUAL_UNION_TYPE && DECL_NAME (new_field) == 0
2179 && (TREE_CODE (TREE_TYPE (new_field)) == UNION_TYPE
2180 || TREE_CODE (TREE_TYPE (new_field)) == RECORD_TYPE))
2182 if (TYPE_FIELDS (TREE_TYPE (new_field)) == 0)
2185 if (TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (new_field))) == 0)
2186 new_field = TYPE_FIELDS (TREE_TYPE (new_field));
2189 DECL_CONTEXT (new_field) = new;
2190 DECL_SIZE (new_field) = 0;
2192 if (TREE_CODE (t) == QUAL_UNION_TYPE)
2194 /* Do the substitution inside the qualifier and if we find
2195 that this field will not be present, omit it. */
2196 DECL_QUALIFIER (new_field)
2197 = substitute_in_expr (DECL_QUALIFIER (field), f, r);
2198 if (integer_zerop (DECL_QUALIFIER (new_field)))
2202 if (last_field == 0)
2203 TYPE_FIELDS (new) = new_field;
2205 TREE_CHAIN (last_field) = new_field;
2207 last_field = new_field;
2209 /* If this is a qualified type and this field will always be
2210 present, we are done. */
2211 if (TREE_CODE (t) == QUAL_UNION_TYPE
2212 && integer_onep (DECL_QUALIFIER (new_field)))
2216 /* If this used to be a qualified union type, but we now know what
2217 field will be present, make this a normal union. */
2218 if (TREE_CODE (new) == QUAL_UNION_TYPE
2219 && (TYPE_FIELDS (new) == 0
2220 || integer_onep (DECL_QUALIFIER (TYPE_FIELDS (new)))))
2221 TREE_SET_CODE (new, UNION_TYPE);
2229 /* Stabilize a reference so that we can use it any number of times
2230 without causing its operands to be evaluated more than once.
2231 Returns the stabilized reference. This works by means of save_expr,
2232 so see the caveats in the comments about save_expr.
2234 Also allows conversion expressions whose operands are references.
2235 Any other kind of expression is returned unchanged. */
2238 stabilize_reference (ref)
2241 register tree result;
2242 register enum tree_code code = TREE_CODE (ref);
2249 /* No action is needed in this case. */
2255 case FIX_TRUNC_EXPR:
2256 case FIX_FLOOR_EXPR:
2257 case FIX_ROUND_EXPR:
2259 result = build_nt (code, stabilize_reference (TREE_OPERAND (ref, 0)));
2263 result = build_nt (INDIRECT_REF,
2264 stabilize_reference_1 (TREE_OPERAND (ref, 0)));
2268 result = build_nt (COMPONENT_REF,
2269 stabilize_reference (TREE_OPERAND (ref, 0)),
2270 TREE_OPERAND (ref, 1));
2274 result = build_nt (BIT_FIELD_REF,
2275 stabilize_reference (TREE_OPERAND (ref, 0)),
2276 stabilize_reference_1 (TREE_OPERAND (ref, 1)),
2277 stabilize_reference_1 (TREE_OPERAND (ref, 2)));
2281 result = build_nt (ARRAY_REF,
2282 stabilize_reference (TREE_OPERAND (ref, 0)),
2283 stabilize_reference_1 (TREE_OPERAND (ref, 1)));
2286 /* If arg isn't a kind of lvalue we recognize, make no change.
2287 Caller should recognize the error for an invalid lvalue. */
2292 return error_mark_node;
2295 TREE_TYPE (result) = TREE_TYPE (ref);
2296 TREE_READONLY (result) = TREE_READONLY (ref);
2297 TREE_SIDE_EFFECTS (result) = TREE_SIDE_EFFECTS (ref);
2298 TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (ref);
2299 TREE_RAISES (result) = TREE_RAISES (ref);
2304 /* Subroutine of stabilize_reference; this is called for subtrees of
2305 references. Any expression with side-effects must be put in a SAVE_EXPR
2306 to ensure that it is only evaluated once.
2308 We don't put SAVE_EXPR nodes around everything, because assigning very
2309 simple expressions to temporaries causes us to miss good opportunities
2310 for optimizations. Among other things, the opportunity to fold in the
2311 addition of a constant into an addressing mode often gets lost, e.g.
2312 "y[i+1] += x;". In general, we take the approach that we should not make
2313 an assignment unless we are forced into it - i.e., that any non-side effect
2314 operator should be allowed, and that cse should take care of coalescing
2315 multiple utterances of the same expression should that prove fruitful. */
2318 stabilize_reference_1 (e)
2321 register tree result;
2322 register int length;
2323 register enum tree_code code = TREE_CODE (e);
2325 /* We cannot ignore const expressions because it might be a reference
2326 to a const array but whose index contains side-effects. But we can
2327 ignore things that are actual constant or that already have been
2328 handled by this function. */
2330 if (TREE_CONSTANT (e) || code == SAVE_EXPR)
2333 switch (TREE_CODE_CLASS (code))
2343 /* If the expression has side-effects, then encase it in a SAVE_EXPR
2344 so that it will only be evaluated once. */
2345 /* The reference (r) and comparison (<) classes could be handled as
2346 below, but it is generally faster to only evaluate them once. */
2347 if (TREE_SIDE_EFFECTS (e))
2348 return save_expr (e);
2352 /* Constants need no processing. In fact, we should never reach
2357 /* Division is slow and tends to be compiled with jumps,
2358 especially the division by powers of 2 that is often
2359 found inside of an array reference. So do it just once. */
2360 if (code == TRUNC_DIV_EXPR || code == TRUNC_MOD_EXPR
2361 || code == FLOOR_DIV_EXPR || code == FLOOR_MOD_EXPR
2362 || code == CEIL_DIV_EXPR || code == CEIL_MOD_EXPR
2363 || code == ROUND_DIV_EXPR || code == ROUND_MOD_EXPR)
2364 return save_expr (e);
2365 /* Recursively stabilize each operand. */
2366 result = build_nt (code, stabilize_reference_1 (TREE_OPERAND (e, 0)),
2367 stabilize_reference_1 (TREE_OPERAND (e, 1)));
2371 /* Recursively stabilize each operand. */
2372 result = build_nt (code, stabilize_reference_1 (TREE_OPERAND (e, 0)));
2376 TREE_TYPE (result) = TREE_TYPE (e);
2377 TREE_READONLY (result) = TREE_READONLY (e);
2378 TREE_SIDE_EFFECTS (result) = TREE_SIDE_EFFECTS (e);
2379 TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (e);
2380 TREE_RAISES (result) = TREE_RAISES (e);
2385 /* Low-level constructors for expressions. */
2387 /* Build an expression of code CODE, data type TYPE,
2388 and operands as specified by the arguments ARG1 and following arguments.
2389 Expressions and reference nodes can be created this way.
2390 Constants, decls, types and misc nodes cannot be. */
2393 build VPROTO((enum tree_code code, tree tt, ...))
2396 enum tree_code code;
2401 register int length;
2407 code = va_arg (p, enum tree_code);
2408 tt = va_arg (p, tree);
2411 t = make_node (code);
2412 length = tree_code_length[(int) code];
2417 /* This is equivalent to the loop below, but faster. */
2418 register tree arg0 = va_arg (p, tree);
2419 register tree arg1 = va_arg (p, tree);
2420 TREE_OPERAND (t, 0) = arg0;
2421 TREE_OPERAND (t, 1) = arg1;
2422 if ((arg0 && TREE_SIDE_EFFECTS (arg0))
2423 || (arg1 && TREE_SIDE_EFFECTS (arg1)))
2424 TREE_SIDE_EFFECTS (t) = 1;
2426 = (arg0 && TREE_RAISES (arg0)) || (arg1 && TREE_RAISES (arg1));
2428 else if (length == 1)
2430 register tree arg0 = va_arg (p, tree);
2432 /* Call build1 for this! */
2433 if (TREE_CODE_CLASS (code) != 's')
2435 TREE_OPERAND (t, 0) = arg0;
2436 if (arg0 && TREE_SIDE_EFFECTS (arg0))
2437 TREE_SIDE_EFFECTS (t) = 1;
2438 TREE_RAISES (t) = (arg0 && TREE_RAISES (arg0));
2442 for (i = 0; i < length; i++)
2444 register tree operand = va_arg (p, tree);
2445 TREE_OPERAND (t, i) = operand;
2448 if (TREE_SIDE_EFFECTS (operand))
2449 TREE_SIDE_EFFECTS (t) = 1;
2450 if (TREE_RAISES (operand))
2451 TREE_RAISES (t) = 1;
2459 /* Same as above, but only builds for unary operators.
2460 Saves lions share of calls to `build'; cuts down use
2461 of varargs, which is expensive for RISC machines. */
2463 build1 (code, type, node)
2464 enum tree_code code;
2468 register struct obstack *obstack = current_obstack;
2469 register int i, length;
2470 register tree_node_kind kind;
2473 #ifdef GATHER_STATISTICS
2474 if (TREE_CODE_CLASS (code) == 'r')
2480 obstack = expression_obstack;
2481 length = sizeof (struct tree_exp);
2483 t = (tree) obstack_alloc (obstack, length);
2485 #ifdef GATHER_STATISTICS
2486 tree_node_counts[(int)kind]++;
2487 tree_node_sizes[(int)kind] += length;
2490 for (i = (length / sizeof (int)) - 1; i >= 0; i--)
2493 TREE_TYPE (t) = type;
2494 TREE_SET_CODE (t, code);
2496 if (obstack == &permanent_obstack)
2497 TREE_PERMANENT (t) = 1;
2499 TREE_OPERAND (t, 0) = node;
2502 if (TREE_SIDE_EFFECTS (node))
2503 TREE_SIDE_EFFECTS (t) = 1;
2504 if (TREE_RAISES (node))
2505 TREE_RAISES (t) = 1;
2511 /* Similar except don't specify the TREE_TYPE
2512 and leave the TREE_SIDE_EFFECTS as 0.
2513 It is permissible for arguments to be null,
2514 or even garbage if their values do not matter. */
2517 build_nt VPROTO((register enum tree_code code, ...))
2520 register enum tree_code code;
2524 register int length;
2530 code = va_arg (p, enum tree_code);
2533 t = make_node (code);
2534 length = tree_code_length[(int) code];
2536 for (i = 0; i < length; i++)
2537 TREE_OPERAND (t, i) = va_arg (p, tree);
2543 /* Similar to `build_nt', except we build
2544 on the temp_decl_obstack, regardless. */
2547 build_parse_node VPROTO((register enum tree_code code, ...))
2550 register enum tree_code code;
2552 register struct obstack *ambient_obstack = expression_obstack;
2555 register int length;
2561 code = va_arg (p, enum tree_code);
2564 expression_obstack = &temp_decl_obstack;
2566 t = make_node (code);
2567 length = tree_code_length[(int) code];
2569 for (i = 0; i < length; i++)
2570 TREE_OPERAND (t, i) = va_arg (p, tree);
2573 expression_obstack = ambient_obstack;
2578 /* Commented out because this wants to be done very
2579 differently. See cp-lex.c. */
2581 build_op_identifier (op1, op2)
2584 register tree t = make_node (OP_IDENTIFIER);
2585 TREE_PURPOSE (t) = op1;
2586 TREE_VALUE (t) = op2;
2591 /* Create a DECL_... node of code CODE, name NAME and data type TYPE.
2592 We do NOT enter this node in any sort of symbol table.
2594 layout_decl is used to set up the decl's storage layout.
2595 Other slots are initialized to 0 or null pointers. */
2598 build_decl (code, name, type)
2599 enum tree_code code;
2604 t = make_node (code);
2606 /* if (type == error_mark_node)
2607 type = integer_type_node; */
2608 /* That is not done, deliberately, so that having error_mark_node
2609 as the type can suppress useless errors in the use of this variable. */
2611 DECL_NAME (t) = name;
2612 DECL_ASSEMBLER_NAME (t) = name;
2613 TREE_TYPE (t) = type;
2615 if (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
2617 else if (code == FUNCTION_DECL)
2618 DECL_MODE (t) = FUNCTION_MODE;
2623 /* BLOCK nodes are used to represent the structure of binding contours
2624 and declarations, once those contours have been exited and their contents
2625 compiled. This information is used for outputting debugging info. */
2628 build_block (vars, tags, subblocks, supercontext, chain)
2629 tree vars, tags, subblocks, supercontext, chain;
2631 register tree block = make_node (BLOCK);
2632 BLOCK_VARS (block) = vars;
2633 BLOCK_TYPE_TAGS (block) = tags;
2634 BLOCK_SUBBLOCKS (block) = subblocks;
2635 BLOCK_SUPERCONTEXT (block) = supercontext;
2636 BLOCK_CHAIN (block) = chain;
2640 /* Return a type like TYPE except that its TYPE_READONLY is CONSTP
2641 and its TYPE_VOLATILE is VOLATILEP.
2643 Such variant types already made are recorded so that duplicates
2646 A variant types should never be used as the type of an expression.
2647 Always copy the variant information into the TREE_READONLY
2648 and TREE_THIS_VOLATILE of the expression, and then give the expression
2649 as its type the "main variant", the variant whose TYPE_READONLY
2650 and TYPE_VOLATILE are zero. Use TYPE_MAIN_VARIANT to find the
2654 build_type_variant (type, constp, volatilep)
2656 int constp, volatilep;
2660 /* Treat any nonzero argument as 1. */
2662 volatilep = !!volatilep;
2664 /* If not generating auxiliary info, search the chain of variants to see
2665 if there is already one there just like the one we need to have. If so,
2666 use that existing one.
2668 We don't do this in the case where we are generating aux info because
2669 in that case we want each typedef names to get it's own distinct type
2670 node, even if the type of this new typedef is the same as some other
2673 if (!flag_gen_aux_info)
2674 for (t = TYPE_MAIN_VARIANT(type); t; t = TYPE_NEXT_VARIANT (t))
2675 if (constp == TYPE_READONLY (t) && volatilep == TYPE_VOLATILE (t))
2678 /* We need a new one. */
2680 t = build_type_copy (type);
2681 TYPE_READONLY (t) = constp;
2682 TYPE_VOLATILE (t) = volatilep;
2687 /* Give TYPE a new main variant: NEW_MAIN.
2688 This is the right thing to do only when something else
2689 about TYPE is modified in place. */
2692 change_main_variant (type, new_main)
2693 tree type, new_main;
2696 tree omain = TYPE_MAIN_VARIANT (type);
2698 /* Remove TYPE from the TYPE_NEXT_VARIANT chain of its main variant. */
2699 if (TYPE_NEXT_VARIANT (omain) == type)
2700 TYPE_NEXT_VARIANT (omain) = TYPE_NEXT_VARIANT (type);
2702 for (t = TYPE_NEXT_VARIANT (omain); t && TYPE_NEXT_VARIANT (t);
2703 t = TYPE_NEXT_VARIANT (t))
2704 if (TYPE_NEXT_VARIANT (t) == type)
2706 TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (type);
2710 TYPE_MAIN_VARIANT (type) = new_main;
2711 TYPE_NEXT_VARIANT (type) = TYPE_NEXT_VARIANT (new_main);
2712 TYPE_NEXT_VARIANT (new_main) = type;
2715 /* Create a new variant of TYPE, equivalent but distinct.
2716 This is so the caller can modify it. */
2719 build_type_copy (type)
2722 register tree t, m = TYPE_MAIN_VARIANT (type);
2723 register struct obstack *ambient_obstack = current_obstack;
2725 current_obstack = TYPE_OBSTACK (type);
2726 t = copy_node (type);
2727 current_obstack = ambient_obstack;
2729 TYPE_POINTER_TO (t) = 0;
2730 TYPE_REFERENCE_TO (t) = 0;
2732 /* Add this type to the chain of variants of TYPE. */
2733 TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
2734 TYPE_NEXT_VARIANT (m) = t;
2739 /* Hashing of types so that we don't make duplicates.
2740 The entry point is `type_hash_canon'. */
2742 /* Each hash table slot is a bucket containing a chain
2743 of these structures. */
2747 struct type_hash *next; /* Next structure in the bucket. */
2748 int hashcode; /* Hash code of this type. */
2749 tree type; /* The type recorded here. */
2752 /* Now here is the hash table. When recording a type, it is added
2753 to the slot whose index is the hash code mod the table size.
2754 Note that the hash table is used for several kinds of types
2755 (function types, array types and array index range types, for now).
2756 While all these live in the same table, they are completely independent,
2757 and the hash code is computed differently for each of these. */
2759 #define TYPE_HASH_SIZE 59
2760 struct type_hash *type_hash_table[TYPE_HASH_SIZE];
2762 /* Here is how primitive or already-canonicalized types' hash
2764 #define TYPE_HASH(TYPE) ((HOST_WIDE_INT) (TYPE) & 0777777)
2766 /* Compute a hash code for a list of types (chain of TREE_LIST nodes
2767 with types in the TREE_VALUE slots), by adding the hash codes
2768 of the individual types. */
2771 type_hash_list (list)
2774 register int hashcode;
2776 for (hashcode = 0, tail = list; tail; tail = TREE_CHAIN (tail))
2777 hashcode += TYPE_HASH (TREE_VALUE (tail));
2781 /* Look in the type hash table for a type isomorphic to TYPE.
2782 If one is found, return it. Otherwise return 0. */
2785 type_hash_lookup (hashcode, type)
2789 register struct type_hash *h;
2790 for (h = type_hash_table[hashcode % TYPE_HASH_SIZE]; h; h = h->next)
2791 if (h->hashcode == hashcode
2792 && TREE_CODE (h->type) == TREE_CODE (type)
2793 && TREE_TYPE (h->type) == TREE_TYPE (type)
2794 && (TYPE_MAX_VALUE (h->type) == TYPE_MAX_VALUE (type)
2795 || tree_int_cst_equal (TYPE_MAX_VALUE (h->type),
2796 TYPE_MAX_VALUE (type)))
2797 && (TYPE_MIN_VALUE (h->type) == TYPE_MIN_VALUE (type)
2798 || tree_int_cst_equal (TYPE_MIN_VALUE (h->type),
2799 TYPE_MIN_VALUE (type)))
2800 && (TYPE_DOMAIN (h->type) == TYPE_DOMAIN (type)
2801 || (TYPE_DOMAIN (h->type)
2802 && TREE_CODE (TYPE_DOMAIN (h->type)) == TREE_LIST
2803 && TYPE_DOMAIN (type)
2804 && TREE_CODE (TYPE_DOMAIN (type)) == TREE_LIST
2805 && type_list_equal (TYPE_DOMAIN (h->type), TYPE_DOMAIN (type)))))
2810 /* Add an entry to the type-hash-table
2811 for a type TYPE whose hash code is HASHCODE. */
2814 type_hash_add (hashcode, type)
2818 register struct type_hash *h;
2820 h = (struct type_hash *) oballoc (sizeof (struct type_hash));
2821 h->hashcode = hashcode;
2823 h->next = type_hash_table[hashcode % TYPE_HASH_SIZE];
2824 type_hash_table[hashcode % TYPE_HASH_SIZE] = h;
2827 /* Given TYPE, and HASHCODE its hash code, return the canonical
2828 object for an identical type if one already exists.
2829 Otherwise, return TYPE, and record it as the canonical object
2830 if it is a permanent object.
2832 To use this function, first create a type of the sort you want.
2833 Then compute its hash code from the fields of the type that
2834 make it different from other similar types.
2835 Then call this function and use the value.
2836 This function frees the type you pass in if it is a duplicate. */
2838 /* Set to 1 to debug without canonicalization. Never set by program. */
2839 int debug_no_type_hash = 0;
2842 type_hash_canon (hashcode, type)
2848 if (debug_no_type_hash)
2851 t1 = type_hash_lookup (hashcode, type);
2854 obstack_free (TYPE_OBSTACK (type), type);
2855 #ifdef GATHER_STATISTICS
2856 tree_node_counts[(int)t_kind]--;
2857 tree_node_sizes[(int)t_kind] -= sizeof (struct tree_type);
2862 /* If this is a permanent type, record it for later reuse. */
2863 if (TREE_PERMANENT (type))
2864 type_hash_add (hashcode, type);
2869 /* Given two lists of types
2870 (chains of TREE_LIST nodes with types in the TREE_VALUE slots)
2871 return 1 if the lists contain the same types in the same order.
2872 Also, the TREE_PURPOSEs must match. */
2875 type_list_equal (l1, l2)
2878 register tree t1, t2;
2879 for (t1 = l1, t2 = l2; t1 && t2; t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
2881 if (TREE_VALUE (t1) != TREE_VALUE (t2))
2883 if (TREE_PURPOSE (t1) != TREE_PURPOSE (t2))
2885 int cmp = simple_cst_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2));
2896 /* Nonzero if integer constants T1 and T2
2897 represent the same constant value. */
2900 tree_int_cst_equal (t1, t2)
2905 if (t1 == 0 || t2 == 0)
2907 if (TREE_CODE (t1) == INTEGER_CST
2908 && TREE_CODE (t2) == INTEGER_CST
2909 && TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
2910 && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2))
2915 /* Nonzero if integer constants T1 and T2 represent values that satisfy <.
2916 The precise way of comparison depends on their data type. */
2919 tree_int_cst_lt (t1, t2)
2925 if (!TREE_UNSIGNED (TREE_TYPE (t1)))
2926 return INT_CST_LT (t1, t2);
2927 return INT_CST_LT_UNSIGNED (t1, t2);
2930 /* Compare two constructor-element-type constants. */
2932 simple_cst_list_equal (l1, l2)
2935 while (l1 != NULL_TREE && l2 != NULL_TREE)
2937 int cmp = simple_cst_equal (TREE_VALUE (l1), TREE_VALUE (l2));
2942 l1 = TREE_CHAIN (l1);
2943 l2 = TREE_CHAIN (l2);
2948 /* Return truthvalue of whether T1 is the same tree structure as T2.
2949 Return 1 if they are the same.
2950 Return 0 if they are understandably different.
2951 Return -1 if either contains tree structure not understood by
2955 simple_cst_equal (t1, t2)
2958 register enum tree_code code1, code2;
2963 if (t1 == 0 || t2 == 0)
2966 code1 = TREE_CODE (t1);
2967 code2 = TREE_CODE (t2);
2969 if (code1 == NOP_EXPR || code1 == CONVERT_EXPR || code1 == NON_LVALUE_EXPR)
2970 if (code2 == NOP_EXPR || code2 == CONVERT_EXPR || code2 == NON_LVALUE_EXPR)
2971 return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
2973 return simple_cst_equal (TREE_OPERAND (t1, 0), t2);
2974 else if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
2975 || code2 == NON_LVALUE_EXPR)
2976 return simple_cst_equal (t1, TREE_OPERAND (t2, 0));
2984 return TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
2985 && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2);
2988 return REAL_VALUES_EQUAL (TREE_REAL_CST (t1), TREE_REAL_CST (t2));
2991 return TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
2992 && !bcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
2993 TREE_STRING_LENGTH (t1));
2999 return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
3002 cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
3005 return simple_cst_list_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
3008 /* Special case: if either target is an unallocated VAR_DECL,
3009 it means that it's going to be unified with whatever the
3010 TARGET_EXPR is really supposed to initialize, so treat it
3011 as being equivalent to anything. */
3012 if ((TREE_CODE (TREE_OPERAND (t1, 0)) == VAR_DECL
3013 && DECL_NAME (TREE_OPERAND (t1, 0)) == NULL_TREE
3014 && DECL_RTL (TREE_OPERAND (t1, 0)) == 0)
3015 || (TREE_CODE (TREE_OPERAND (t2, 0)) == VAR_DECL
3016 && DECL_NAME (TREE_OPERAND (t2, 0)) == NULL_TREE
3017 && DECL_RTL (TREE_OPERAND (t2, 0)) == 0))
3020 cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
3023 return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
3025 case WITH_CLEANUP_EXPR:
3026 cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
3029 return simple_cst_equal (TREE_OPERAND (t1, 2), TREE_OPERAND (t1, 2));
3032 if (TREE_OPERAND (t1, 1) == TREE_OPERAND (t2, 1))
3033 return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
3043 /* This general rule works for most tree codes.
3044 All exceptions should be handled above. */
3046 switch (TREE_CODE_CLASS (code1))
3056 for (i=0; i<tree_code_length[(int) code1]; ++i)
3058 cmp = simple_cst_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i));
3068 /* Constructors for pointer, array and function types.
3069 (RECORD_TYPE, UNION_TYPE and ENUMERAL_TYPE nodes are
3070 constructed by language-dependent code, not here.) */
3072 /* Construct, lay out and return the type of pointers to TO_TYPE.
3073 If such a type has already been constructed, reuse it. */
3076 build_pointer_type (to_type)
3079 register tree t = TYPE_POINTER_TO (to_type);
3081 /* First, if we already have a type for pointers to TO_TYPE, use it. */
3086 /* We need a new one. Put this in the same obstack as TO_TYPE. */
3087 push_obstacks (TYPE_OBSTACK (to_type), TYPE_OBSTACK (to_type));
3088 t = make_node (POINTER_TYPE);
3091 TREE_TYPE (t) = to_type;
3093 /* Record this type as the pointer to TO_TYPE. */
3094 TYPE_POINTER_TO (to_type) = t;
3096 /* Lay out the type. This function has many callers that are concerned
3097 with expression-construction, and this simplifies them all.
3098 Also, it guarantees the TYPE_SIZE is in the same obstack as the type. */
3104 /* Create a type of integers to be the TYPE_DOMAIN of an ARRAY_TYPE.
3105 MAXVAL should be the maximum value in the domain
3106 (one less than the length of the array). */
3109 build_index_type (maxval)
3112 register tree itype = make_node (INTEGER_TYPE);
3113 TYPE_PRECISION (itype) = TYPE_PRECISION (sizetype);
3114 TYPE_MIN_VALUE (itype) = build_int_2 (0, 0);
3115 TREE_TYPE (TYPE_MIN_VALUE (itype)) = sizetype;
3116 TYPE_MAX_VALUE (itype) = convert (sizetype, maxval);
3117 TYPE_MODE (itype) = TYPE_MODE (sizetype);
3118 TYPE_SIZE (itype) = TYPE_SIZE (sizetype);
3119 TYPE_ALIGN (itype) = TYPE_ALIGN (sizetype);
3120 if (TREE_CODE (maxval) == INTEGER_CST)
3122 int maxint = (int) TREE_INT_CST_LOW (maxval);
3123 /* If the domain should be empty, make sure the maxval
3124 remains -1 and is not spoiled by truncation. */
3125 if (INT_CST_LT (maxval, integer_zero_node))
3127 TYPE_MAX_VALUE (itype) = build_int_2 (-1, -1);
3128 TREE_TYPE (TYPE_MAX_VALUE (itype)) = sizetype;
3130 return type_hash_canon (maxint < 0 ? ~maxint : maxint, itype);
3136 /* Create a range of some discrete type TYPE (an INTEGER_TYPE,
3137 ENUMERAL_TYPE, BOOLEAN_TYPE, or CHAR_TYPE), with
3138 low bound LOWVAL and high bound HIGHVAL.
3139 if TYPE==NULL_TREE, sizetype is used. */
3142 build_range_type (type, lowval, highval)
3143 tree type, lowval, highval;
3145 register tree itype = make_node (INTEGER_TYPE);
3146 TREE_TYPE (itype) = type;
3147 if (type == NULL_TREE)
3149 TYPE_PRECISION (itype) = TYPE_PRECISION (type);
3150 TYPE_MIN_VALUE (itype) = convert (type, lowval);
3151 TYPE_MAX_VALUE (itype) = convert (type, highval);
3152 TYPE_MODE (itype) = TYPE_MODE (type);
3153 TYPE_SIZE (itype) = TYPE_SIZE (type);
3154 TYPE_ALIGN (itype) = TYPE_ALIGN (type);
3155 if ((TREE_CODE (lowval) == INTEGER_CST)
3156 && (TREE_CODE (highval) == INTEGER_CST))
3158 HOST_WIDE_INT highint = TREE_INT_CST_LOW (highval);
3159 HOST_WIDE_INT lowint = TREE_INT_CST_LOW (lowval);
3160 int maxint = (int) (highint - lowint);
3161 return type_hash_canon (maxint < 0 ? ~maxint : maxint, itype);
3167 /* Just like build_index_type, but takes lowval and highval instead
3168 of just highval (maxval). */
3171 build_index_2_type (lowval,highval)
3172 tree lowval, highval;
3174 return build_range_type (NULL_TREE, lowval, highval);
3177 /* Return nonzero iff ITYPE1 and ITYPE2 are equal (in the LISP sense).
3178 Needed because when index types are not hashed, equal index types
3179 built at different times appear distinct, even though structurally,
3183 index_type_equal (itype1, itype2)
3184 tree itype1, itype2;
3186 if (TREE_CODE (itype1) != TREE_CODE (itype2))
3188 if (TREE_CODE (itype1) == INTEGER_TYPE)
3190 if (TYPE_PRECISION (itype1) != TYPE_PRECISION (itype2)
3191 || TYPE_MODE (itype1) != TYPE_MODE (itype2)
3192 || ! simple_cst_equal (TYPE_SIZE (itype1), TYPE_SIZE (itype2))
3193 || TYPE_ALIGN (itype1) != TYPE_ALIGN (itype2))
3195 if (simple_cst_equal (TYPE_MIN_VALUE (itype1), TYPE_MIN_VALUE (itype2))
3196 && simple_cst_equal (TYPE_MAX_VALUE (itype1), TYPE_MAX_VALUE (itype2)))
3202 /* Construct, lay out and return the type of arrays of elements with ELT_TYPE
3203 and number of elements specified by the range of values of INDEX_TYPE.
3204 If such a type has already been constructed, reuse it. */
3207 build_array_type (elt_type, index_type)
3208 tree elt_type, index_type;
3213 if (TREE_CODE (elt_type) == FUNCTION_TYPE)
3215 error ("arrays of functions are not meaningful");
3216 elt_type = integer_type_node;
3219 /* Make sure TYPE_POINTER_TO (elt_type) is filled in. */
3220 build_pointer_type (elt_type);
3222 /* Allocate the array after the pointer type,
3223 in case we free it in type_hash_canon. */
3224 t = make_node (ARRAY_TYPE);
3225 TREE_TYPE (t) = elt_type;
3226 TYPE_DOMAIN (t) = index_type;
3228 if (index_type == 0)
3233 hashcode = TYPE_HASH (elt_type) + TYPE_HASH (index_type);
3234 t = type_hash_canon (hashcode, t);
3236 #if 0 /* This led to crashes, because it could put a temporary node
3237 on the TYPE_NEXT_VARIANT chain of a permanent one. */
3238 /* The main variant of an array type should always
3239 be an array whose element type is the main variant. */
3240 if (elt_type != TYPE_MAIN_VARIANT (elt_type))
3241 change_main_variant (t, build_array_type (TYPE_MAIN_VARIANT (elt_type),
3245 if (TYPE_SIZE (t) == 0)
3250 /* Construct, lay out and return
3251 the type of functions returning type VALUE_TYPE
3252 given arguments of types ARG_TYPES.
3253 ARG_TYPES is a chain of TREE_LIST nodes whose TREE_VALUEs
3254 are data type nodes for the arguments of the function.
3255 If such a type has already been constructed, reuse it. */
3258 build_function_type (value_type, arg_types)
3259 tree value_type, arg_types;
3264 if (TREE_CODE (value_type) == FUNCTION_TYPE)
3266 error ("function return type cannot be function");
3267 value_type = integer_type_node;
3270 /* Make a node of the sort we want. */
3271 t = make_node (FUNCTION_TYPE);
3272 TREE_TYPE (t) = value_type;
3273 TYPE_ARG_TYPES (t) = arg_types;
3275 /* If we already have such a type, use the old one and free this one. */
3276 hashcode = TYPE_HASH (value_type) + type_hash_list (arg_types);
3277 t = type_hash_canon (hashcode, t);
3279 if (TYPE_SIZE (t) == 0)
3284 /* Build the node for the type of references-to-TO_TYPE. */
3287 build_reference_type (to_type)
3290 register tree t = TYPE_REFERENCE_TO (to_type);
3291 register struct obstack *ambient_obstack = current_obstack;
3292 register struct obstack *ambient_saveable_obstack = saveable_obstack;
3294 /* First, if we already have a type for pointers to TO_TYPE, use it. */
3299 /* We need a new one. If TO_TYPE is permanent, make this permanent too. */
3300 if (TREE_PERMANENT (to_type))
3302 current_obstack = &permanent_obstack;
3303 saveable_obstack = &permanent_obstack;
3306 t = make_node (REFERENCE_TYPE);
3307 TREE_TYPE (t) = to_type;
3309 /* Record this type as the pointer to TO_TYPE. */
3310 TYPE_REFERENCE_TO (to_type) = t;
3314 current_obstack = ambient_obstack;
3315 saveable_obstack = ambient_saveable_obstack;
3319 /* Construct, lay out and return the type of methods belonging to class
3320 BASETYPE and whose arguments and values are described by TYPE.
3321 If that type exists already, reuse it.
3322 TYPE must be a FUNCTION_TYPE node. */
3325 build_method_type (basetype, type)
3326 tree basetype, type;
3331 /* Make a node of the sort we want. */
3332 t = make_node (METHOD_TYPE);
3334 if (TREE_CODE (type) != FUNCTION_TYPE)
3337 TYPE_METHOD_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
3338 TREE_TYPE (t) = TREE_TYPE (type);
3340 /* The actual arglist for this function includes a "hidden" argument
3341 which is "this". Put it into the list of argument types. */
3344 = tree_cons (NULL_TREE,
3345 build_pointer_type (basetype), TYPE_ARG_TYPES (type));
3347 /* If we already have such a type, use the old one and free this one. */
3348 hashcode = TYPE_HASH (basetype) + TYPE_HASH (type);
3349 t = type_hash_canon (hashcode, t);
3351 if (TYPE_SIZE (t) == 0)
3357 /* Construct, lay out and return the type of offsets to a value
3358 of type TYPE, within an object of type BASETYPE.
3359 If a suitable offset type exists already, reuse it. */
3362 build_offset_type (basetype, type)
3363 tree basetype, type;
3368 /* Make a node of the sort we want. */
3369 t = make_node (OFFSET_TYPE);
3371 TYPE_OFFSET_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
3372 TREE_TYPE (t) = type;
3374 /* If we already have such a type, use the old one and free this one. */
3375 hashcode = TYPE_HASH (basetype) + TYPE_HASH (type);
3376 t = type_hash_canon (hashcode, t);
3378 if (TYPE_SIZE (t) == 0)
3384 /* Create a complex type whose components are COMPONENT_TYPE. */
3387 build_complex_type (component_type)
3388 tree component_type;
3393 /* Make a node of the sort we want. */
3394 t = make_node (COMPLEX_TYPE);
3396 TREE_TYPE (t) = TYPE_MAIN_VARIANT (component_type);
3397 TYPE_VOLATILE (t) = TYPE_VOLATILE (component_type);
3398 TYPE_READONLY (t) = TYPE_READONLY (component_type);
3400 /* If we already have such a type, use the old one and free this one. */
3401 hashcode = TYPE_HASH (component_type);
3402 t = type_hash_canon (hashcode, t);
3404 if (TYPE_SIZE (t) == 0)
3410 /* Return OP, stripped of any conversions to wider types as much as is safe.
3411 Converting the value back to OP's type makes a value equivalent to OP.
3413 If FOR_TYPE is nonzero, we return a value which, if converted to
3414 type FOR_TYPE, would be equivalent to converting OP to type FOR_TYPE.
3416 If FOR_TYPE is nonzero, unaligned bit-field references may be changed to the
3417 narrowest type that can hold the value, even if they don't exactly fit.
3418 Otherwise, bit-field references are changed to a narrower type
3419 only if they can be fetched directly from memory in that type.
3421 OP must have integer, real or enumeral type. Pointers are not allowed!
3423 There are some cases where the obvious value we could return
3424 would regenerate to OP if converted to OP's type,
3425 but would not extend like OP to wider types.
3426 If FOR_TYPE indicates such extension is contemplated, we eschew such values.
3427 For example, if OP is (unsigned short)(signed char)-1,
3428 we avoid returning (signed char)-1 if FOR_TYPE is int,
3429 even though extending that to an unsigned short would regenerate OP,
3430 since the result of extending (signed char)-1 to (int)
3431 is different from (int) OP. */
3434 get_unwidened (op, for_type)
3438 /* Set UNS initially if converting OP to FOR_TYPE is a zero-extension. */
3439 /* TYPE_PRECISION is safe in place of type_precision since
3440 pointer types are not allowed. */
3441 register tree type = TREE_TYPE (op);
3442 register unsigned final_prec
3443 = TYPE_PRECISION (for_type != 0 ? for_type : type);
3445 = (for_type != 0 && for_type != type
3446 && final_prec > TYPE_PRECISION (type)
3447 && TREE_UNSIGNED (type));
3448 register tree win = op;
3450 while (TREE_CODE (op) == NOP_EXPR)
3452 register int bitschange
3453 = TYPE_PRECISION (TREE_TYPE (op))
3454 - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0)));
3456 /* Truncations are many-one so cannot be removed.
3457 Unless we are later going to truncate down even farther. */
3459 && final_prec > TYPE_PRECISION (TREE_TYPE (op)))
3462 /* See what's inside this conversion. If we decide to strip it,
3464 op = TREE_OPERAND (op, 0);
3466 /* If we have not stripped any zero-extensions (uns is 0),
3467 we can strip any kind of extension.
3468 If we have previously stripped a zero-extension,
3469 only zero-extensions can safely be stripped.
3470 Any extension can be stripped if the bits it would produce
3471 are all going to be discarded later by truncating to FOR_TYPE. */
3475 if (! uns || final_prec <= TYPE_PRECISION (TREE_TYPE (op)))
3477 /* TREE_UNSIGNED says whether this is a zero-extension.
3478 Let's avoid computing it if it does not affect WIN
3479 and if UNS will not be needed again. */
3480 if ((uns || TREE_CODE (op) == NOP_EXPR)
3481 && TREE_UNSIGNED (TREE_TYPE (op)))
3489 if (TREE_CODE (op) == COMPONENT_REF
3490 /* Since type_for_size always gives an integer type. */
3491 && TREE_CODE (type) != REAL_TYPE)
3493 unsigned innerprec = TREE_INT_CST_LOW (DECL_SIZE (TREE_OPERAND (op, 1)));
3494 type = type_for_size (innerprec, TREE_UNSIGNED (TREE_OPERAND (op, 1)));
3496 /* We can get this structure field in the narrowest type it fits in.
3497 If FOR_TYPE is 0, do this only for a field that matches the
3498 narrower type exactly and is aligned for it
3499 The resulting extension to its nominal type (a fullword type)
3500 must fit the same conditions as for other extensions. */
3502 if (innerprec < TYPE_PRECISION (TREE_TYPE (op))
3503 && (for_type || ! DECL_BIT_FIELD (TREE_OPERAND (op, 1)))
3504 && (! uns || final_prec <= innerprec
3505 || TREE_UNSIGNED (TREE_OPERAND (op, 1)))
3508 win = build (COMPONENT_REF, type, TREE_OPERAND (op, 0),
3509 TREE_OPERAND (op, 1));
3510 TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
3511 TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
3512 TREE_RAISES (win) = TREE_RAISES (op);
3518 /* Return OP or a simpler expression for a narrower value
3519 which can be sign-extended or zero-extended to give back OP.
3520 Store in *UNSIGNEDP_PTR either 1 if the value should be zero-extended
3521 or 0 if the value should be sign-extended. */
3524 get_narrower (op, unsignedp_ptr)
3528 register int uns = 0;
3530 register tree win = op;
3532 while (TREE_CODE (op) == NOP_EXPR)
3534 register int bitschange
3535 = TYPE_PRECISION (TREE_TYPE (op))
3536 - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0)));
3538 /* Truncations are many-one so cannot be removed. */
3542 /* See what's inside this conversion. If we decide to strip it,
3544 op = TREE_OPERAND (op, 0);
3548 /* An extension: the outermost one can be stripped,
3549 but remember whether it is zero or sign extension. */
3551 uns = TREE_UNSIGNED (TREE_TYPE (op));
3552 /* Otherwise, if a sign extension has been stripped,
3553 only sign extensions can now be stripped;
3554 if a zero extension has been stripped, only zero-extensions. */
3555 else if (uns != TREE_UNSIGNED (TREE_TYPE (op)))
3559 else /* bitschange == 0 */
3561 /* A change in nominal type can always be stripped, but we must
3562 preserve the unsignedness. */
3564 uns = TREE_UNSIGNED (TREE_TYPE (op));
3571 if (TREE_CODE (op) == COMPONENT_REF
3572 /* Since type_for_size always gives an integer type. */
3573 && TREE_CODE (TREE_TYPE (op)) != REAL_TYPE)
3575 unsigned innerprec = TREE_INT_CST_LOW (DECL_SIZE (TREE_OPERAND (op, 1)));
3576 tree type = type_for_size (innerprec, TREE_UNSIGNED (op));
3578 /* We can get this structure field in a narrower type that fits it,
3579 but the resulting extension to its nominal type (a fullword type)
3580 must satisfy the same conditions as for other extensions.
3582 Do this only for fields that are aligned (not bit-fields),
3583 because when bit-field insns will be used there is no
3584 advantage in doing this. */
3586 if (innerprec < TYPE_PRECISION (TREE_TYPE (op))
3587 && ! DECL_BIT_FIELD (TREE_OPERAND (op, 1))
3588 && (first || uns == TREE_UNSIGNED (TREE_OPERAND (op, 1)))
3592 uns = TREE_UNSIGNED (TREE_OPERAND (op, 1));
3593 win = build (COMPONENT_REF, type, TREE_OPERAND (op, 0),
3594 TREE_OPERAND (op, 1));
3595 TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
3596 TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
3597 TREE_RAISES (win) = TREE_RAISES (op);
3600 *unsignedp_ptr = uns;
3604 /* Return the precision of a type, for arithmetic purposes.
3605 Supports all types on which arithmetic is possible
3606 (including pointer types).
3607 It's not clear yet what will be right for complex types. */
3610 type_precision (type)
3613 return ((TREE_CODE (type) == INTEGER_TYPE
3614 || TREE_CODE (type) == ENUMERAL_TYPE
3615 || TREE_CODE (type) == REAL_TYPE)
3616 ? TYPE_PRECISION (type) : POINTER_SIZE);
3619 /* Nonzero if integer constant C has a value that is permissible
3620 for type TYPE (an INTEGER_TYPE). */
3623 int_fits_type_p (c, type)
3626 if (TREE_UNSIGNED (type))
3627 return (! (TREE_CODE (TYPE_MAX_VALUE (type)) == INTEGER_CST
3628 && INT_CST_LT_UNSIGNED (TYPE_MAX_VALUE (type), c))
3629 && ! (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
3630 && INT_CST_LT_UNSIGNED (c, TYPE_MIN_VALUE (type))));
3632 return (! (TREE_CODE (TYPE_MAX_VALUE (type)) == INTEGER_CST
3633 && INT_CST_LT (TYPE_MAX_VALUE (type), c))
3634 && ! (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
3635 && INT_CST_LT (c, TYPE_MIN_VALUE (type))));
3638 /* Return the innermost context enclosing DECL that is
3639 a FUNCTION_DECL, or zero if none. */
3642 decl_function_context (decl)
3647 if (TREE_CODE (decl) == ERROR_MARK)
3650 if (TREE_CODE (decl) == SAVE_EXPR)
3651 context = SAVE_EXPR_CONTEXT (decl);
3653 context = DECL_CONTEXT (decl);
3655 while (context && TREE_CODE (context) != FUNCTION_DECL)
3657 if (TREE_CODE (context) == RECORD_TYPE
3658 || TREE_CODE (context) == UNION_TYPE)
3659 context = TYPE_CONTEXT (context);
3660 else if (TREE_CODE (context) == TYPE_DECL)
3661 context = DECL_CONTEXT (context);
3662 else if (TREE_CODE (context) == BLOCK)
3663 context = BLOCK_SUPERCONTEXT (context);
3665 /* Unhandled CONTEXT !? */
3672 /* Return the innermost context enclosing DECL that is
3673 a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE, or zero if none.
3674 TYPE_DECLs and FUNCTION_DECLs are transparent to this function. */
3677 decl_type_context (decl)
3680 tree context = DECL_CONTEXT (decl);
3684 if (TREE_CODE (context) == RECORD_TYPE
3685 || TREE_CODE (context) == UNION_TYPE
3686 || TREE_CODE (context) == QUAL_UNION_TYPE)
3688 if (TREE_CODE (context) == TYPE_DECL
3689 || TREE_CODE (context) == FUNCTION_DECL)
3690 context = DECL_CONTEXT (context);
3691 else if (TREE_CODE (context) == BLOCK)
3692 context = BLOCK_SUPERCONTEXT (context);
3694 /* Unhandled CONTEXT!? */
3701 print_obstack_statistics (str, o)
3705 struct _obstack_chunk *chunk = o->chunk;
3712 n_alloc += chunk->limit - &chunk->contents[0];
3713 chunk = chunk->prev;
3715 fprintf (stderr, "obstack %s: %d bytes, %d chunks\n",
3716 str, n_alloc, n_chunks);
3719 dump_tree_statistics ()
3722 int total_nodes, total_bytes;
3724 fprintf (stderr, "\n??? tree nodes created\n\n");
3725 #ifdef GATHER_STATISTICS
3726 fprintf (stderr, "Kind Nodes Bytes\n");
3727 fprintf (stderr, "-------------------------------------\n");
3728 total_nodes = total_bytes = 0;
3729 for (i = 0; i < (int) all_kinds; i++)
3731 fprintf (stderr, "%-20s %6d %9d\n", tree_node_kind_names[i],
3732 tree_node_counts[i], tree_node_sizes[i]);
3733 total_nodes += tree_node_counts[i];
3734 total_bytes += tree_node_sizes[i];
3736 fprintf (stderr, "%-20s %9d\n", "identifier names", id_string_size);
3737 fprintf (stderr, "-------------------------------------\n");
3738 fprintf (stderr, "%-20s %6d %9d\n", "Total", total_nodes, total_bytes);
3739 fprintf (stderr, "-------------------------------------\n");
3741 fprintf (stderr, "(No per-node statistics)\n");
3743 print_lang_statistics ();
3746 #define FILE_FUNCTION_PREFIX_LEN 9
3748 #ifndef NO_DOLLAR_IN_LABEL
3749 #define FILE_FUNCTION_FORMAT "_GLOBAL_$D$%s"
3750 #else /* NO_DOLLAR_IN_LABEL */
3751 #ifndef NO_DOT_IN_LABEL
3752 #define FILE_FUNCTION_FORMAT "_GLOBAL_.D.%s"
3753 #else /* NO_DOT_IN_LABEL */
3754 #define FILE_FUNCTION_FORMAT "_GLOBAL__D_%s"
3755 #endif /* NO_DOT_IN_LABEL */
3756 #endif /* NO_DOLLAR_IN_LABEL */
3758 extern char * first_global_object_name;
3760 /* If KIND=='I', return a suitable global initializer (constructor) name.
3761 If KIND=='D', return a suitable global clean-up (destructor) name. */
3764 get_file_function_name (kind)
3770 if (first_global_object_name)
3771 p = first_global_object_name;
3772 else if (main_input_filename)
3773 p = main_input_filename;
3777 buf = (char *) alloca (sizeof (FILE_FUNCTION_FORMAT) + strlen (p));
3779 /* Set up the name of the file-level functions we may need. */
3780 /* Use a global object (which is already required to be unique over
3781 the program) rather than the file name (which imposes extra
3782 constraints). -- Raeburn@MIT.EDU, 10 Jan 1990. */
3783 sprintf (buf, FILE_FUNCTION_FORMAT, p);
3785 /* Don't need to pull wierd characters out of global names. */
3786 if (p != first_global_object_name)
3788 for (p = buf+11; *p; p++)
3789 if (! ((*p >= '0' && *p <= '9')
3790 #if 0 /* we always want labels, which are valid C++ identifiers (+ `$') */
3791 #ifndef ASM_IDENTIFY_GCC /* this is required if `.' is invalid -- k. raeburn */
3795 #ifndef NO_DOLLAR_IN_LABEL /* this for `$'; unlikely, but... -- kr */
3798 #ifndef NO_DOT_IN_LABEL /* this for `.'; unlikely, but... */
3801 || (*p >= 'A' && *p <= 'Z')
3802 || (*p >= 'a' && *p <= 'z')))
3806 buf[FILE_FUNCTION_PREFIX_LEN] = kind;
3808 return get_identifier (buf);