1 /****************************************************************************
3 * GNAT COMPILER COMPONENTS *
7 * C Implementation File *
9 * Copyright (C) 1992-2006, Free Software Foundation, Inc. *
11 * GNAT is free software; you can redistribute it and/or modify it under *
12 * terms of the GNU General Public License as published by the Free Soft- *
13 * ware Foundation; either version 2, or (at your option) any later ver- *
14 * sion. GNAT is distributed in the hope that it will be useful, but WITH- *
15 * OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY *
16 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
17 * for more details. You should have received a copy of the GNU General *
18 * Public License distributed with GNAT; see file COPYING. If not, write *
19 * to the Free Software Foundation, 51 Franklin Street, Fifth Floor, *
20 * Boston, MA 02110-1301, USA. *
22 * GNAT was originally developed by the GNAT team at New York University. *
23 * Extensive contributions were provided by Ada Core Technologies Inc. *
25 ****************************************************************************/
29 #include "coretypes.h"
42 #include "tree-inline.h"
43 #include "tree-gimple.h"
44 #include "tree-dump.h"
60 #ifndef MAX_FIXED_MODE_SIZE
61 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
64 #ifndef MAX_BITS_PER_WORD
65 #define MAX_BITS_PER_WORD BITS_PER_WORD
68 /* If nonzero, pretend we are allocating at global level. */
71 /* Tree nodes for the various types and decls we create. */
72 tree gnat_std_decls[(int) ADT_LAST];
74 /* Functions to call for each of the possible raise reasons. */
75 tree gnat_raise_decls[(int) LAST_REASON_CODE + 1];
77 /* List of functions called automatically at the beginning and
78 end of execution, on targets without .ctors/.dtors sections. */
82 /* Associates a GNAT tree node to a GCC tree node. It is used in
83 `save_gnu_tree', `get_gnu_tree' and `present_gnu_tree'. See documentation
84 of `save_gnu_tree' for more info. */
85 static GTY((length ("max_gnat_nodes"))) tree *associate_gnat_to_gnu;
87 /* This variable keeps a table for types for each precision so that we only
88 allocate each of them once. Signed and unsigned types are kept separate.
90 Note that these types are only used when fold-const requests something
91 special. Perhaps we should NOT share these types; we'll see how it
93 static GTY(()) tree signed_and_unsigned_types[2 * MAX_BITS_PER_WORD + 1][2];
95 /* Likewise for float types, but record these by mode. */
96 static GTY(()) tree float_types[NUM_MACHINE_MODES];
98 /* For each binding contour we allocate a binding_level structure to indicate
101 struct gnat_binding_level GTY((chain_next ("%h.chain")))
103 /* The binding level containing this one (the enclosing binding level). */
104 struct gnat_binding_level *chain;
105 /* The BLOCK node for this level. */
107 /* If nonzero, the setjmp buffer that needs to be updated for any
108 variable-sized definition within this context. */
112 /* The binding level currently in effect. */
113 static GTY(()) struct gnat_binding_level *current_binding_level;
115 /* A chain of gnat_binding_level structures awaiting reuse. */
116 static GTY((deletable)) struct gnat_binding_level *free_binding_level;
118 /* A chain of unused BLOCK nodes. */
119 static GTY((deletable)) tree free_block_chain;
121 struct language_function GTY(())
126 static void gnat_install_builtins (void);
127 static tree merge_sizes (tree, tree, tree, bool, bool);
128 static tree compute_related_constant (tree, tree);
129 static tree split_plus (tree, tree *);
130 static bool value_zerop (tree);
131 static void gnat_gimplify_function (tree);
132 static tree float_type_for_precision (int, enum machine_mode);
133 static tree convert_to_fat_pointer (tree, tree);
134 static tree convert_to_thin_pointer (tree, tree);
135 static tree make_descriptor_field (const char *,tree, tree, tree);
136 static bool potential_alignment_gap (tree, tree, tree);
138 /* Initialize the association of GNAT nodes to GCC trees. */
141 init_gnat_to_gnu (void)
143 associate_gnat_to_gnu
144 = (tree *) ggc_alloc_cleared (max_gnat_nodes * sizeof (tree));
147 /* GNAT_ENTITY is a GNAT tree node for an entity. GNU_DECL is the GCC tree
148 which is to be associated with GNAT_ENTITY. Such GCC tree node is always
149 a ..._DECL node. If NO_CHECK is nonzero, the latter check is suppressed.
151 If GNU_DECL is zero, a previous association is to be reset. */
154 save_gnu_tree (Entity_Id gnat_entity, tree gnu_decl, bool no_check)
156 /* Check that GNAT_ENTITY is not already defined and that it is being set
157 to something which is a decl. Raise gigi 401 if not. Usually, this
158 means GNAT_ENTITY is defined twice, but occasionally is due to some
160 gcc_assert (!gnu_decl
161 || (!associate_gnat_to_gnu[gnat_entity - First_Node_Id]
162 && (no_check || DECL_P (gnu_decl))));
163 associate_gnat_to_gnu[gnat_entity - First_Node_Id] = gnu_decl;
166 /* GNAT_ENTITY is a GNAT tree node for a defining identifier.
167 Return the ..._DECL node that was associated with it. If there is no tree
168 node associated with GNAT_ENTITY, abort.
170 In some cases, such as delayed elaboration or expressions that need to
171 be elaborated only once, GNAT_ENTITY is really not an entity. */
174 get_gnu_tree (Entity_Id gnat_entity)
176 gcc_assert (associate_gnat_to_gnu[gnat_entity - First_Node_Id]);
177 return associate_gnat_to_gnu[gnat_entity - First_Node_Id];
180 /* Return nonzero if a GCC tree has been associated with GNAT_ENTITY. */
183 present_gnu_tree (Entity_Id gnat_entity)
185 return (associate_gnat_to_gnu[gnat_entity - First_Node_Id]) != 0;
189 /* Return nonzero if we are currently in the global binding level. */
192 global_bindings_p (void)
194 return ((force_global || !current_function_decl) ? -1 : 0);
197 /* Enter a new binding level. */
202 struct gnat_binding_level *newlevel = NULL;
204 /* Reuse a struct for this binding level, if there is one. */
205 if (free_binding_level)
207 newlevel = free_binding_level;
208 free_binding_level = free_binding_level->chain;
212 = (struct gnat_binding_level *)
213 ggc_alloc (sizeof (struct gnat_binding_level));
215 /* Use a free BLOCK, if any; otherwise, allocate one. */
216 if (free_block_chain)
218 newlevel->block = free_block_chain;
219 free_block_chain = TREE_CHAIN (free_block_chain);
220 TREE_CHAIN (newlevel->block) = NULL_TREE;
223 newlevel->block = make_node (BLOCK);
225 /* Point the BLOCK we just made to its parent. */
226 if (current_binding_level)
227 BLOCK_SUPERCONTEXT (newlevel->block) = current_binding_level->block;
229 BLOCK_VARS (newlevel->block) = BLOCK_SUBBLOCKS (newlevel->block) = NULL_TREE;
230 TREE_USED (newlevel->block) = 1;
232 /* Add this level to the front of the chain (stack) of levels that are
234 newlevel->chain = current_binding_level;
235 newlevel->jmpbuf_decl = NULL_TREE;
236 current_binding_level = newlevel;
239 /* Set SUPERCONTEXT of the BLOCK for the current binding level to FNDECL
240 and point FNDECL to this BLOCK. */
243 set_current_block_context (tree fndecl)
245 BLOCK_SUPERCONTEXT (current_binding_level->block) = fndecl;
246 DECL_INITIAL (fndecl) = current_binding_level->block;
249 /* Set the jmpbuf_decl for the current binding level to DECL. */
252 set_block_jmpbuf_decl (tree decl)
254 current_binding_level->jmpbuf_decl = decl;
257 /* Get the jmpbuf_decl, if any, for the current binding level. */
260 get_block_jmpbuf_decl ()
262 return current_binding_level->jmpbuf_decl;
265 /* Exit a binding level. Set any BLOCK into the current code group. */
270 struct gnat_binding_level *level = current_binding_level;
271 tree block = level->block;
273 BLOCK_VARS (block) = nreverse (BLOCK_VARS (block));
274 BLOCK_SUBBLOCKS (block) = nreverse (BLOCK_SUBBLOCKS (block));
276 /* If this is a function-level BLOCK don't do anything. Otherwise, if there
277 are no variables free the block and merge its subblocks into those of its
278 parent block. Otherwise, add it to the list of its parent. */
279 if (TREE_CODE (BLOCK_SUPERCONTEXT (block)) == FUNCTION_DECL)
281 else if (BLOCK_VARS (block) == NULL_TREE)
283 BLOCK_SUBBLOCKS (level->chain->block)
284 = chainon (BLOCK_SUBBLOCKS (block),
285 BLOCK_SUBBLOCKS (level->chain->block));
286 TREE_CHAIN (block) = free_block_chain;
287 free_block_chain = block;
291 TREE_CHAIN (block) = BLOCK_SUBBLOCKS (level->chain->block);
292 BLOCK_SUBBLOCKS (level->chain->block) = block;
293 TREE_USED (block) = 1;
294 set_block_for_group (block);
297 /* Free this binding structure. */
298 current_binding_level = level->chain;
299 level->chain = free_binding_level;
300 free_binding_level = level;
303 /* Insert BLOCK at the end of the list of subblocks of the
304 current binding level. This is used when a BIND_EXPR is expanded,
305 to handle the BLOCK node inside the BIND_EXPR. */
308 insert_block (tree block)
310 TREE_USED (block) = 1;
311 TREE_CHAIN (block) = BLOCK_SUBBLOCKS (current_binding_level->block);
312 BLOCK_SUBBLOCKS (current_binding_level->block) = block;
315 /* Records a ..._DECL node DECL as belonging to the current lexical scope
316 and uses GNAT_NODE for location information and propagating flags. */
319 gnat_pushdecl (tree decl, Node_Id gnat_node)
321 /* If at top level, there is no context. But PARM_DECLs always go in the
322 level of its function. */
323 if (global_bindings_p () && TREE_CODE (decl) != PARM_DECL)
324 DECL_CONTEXT (decl) = 0;
327 DECL_CONTEXT (decl) = current_function_decl;
329 /* Functions imported in another function are not really nested. */
330 if (TREE_CODE (decl) == FUNCTION_DECL && TREE_PUBLIC (decl))
331 DECL_NO_STATIC_CHAIN (decl) = 1;
334 TREE_NO_WARNING (decl) = (gnat_node == Empty || Warnings_Off (gnat_node));
336 /* Set the location of DECL and emit a declaration for it. */
337 if (Present (gnat_node))
338 Sloc_to_locus (Sloc (gnat_node), &DECL_SOURCE_LOCATION (decl));
339 add_decl_expr (decl, gnat_node);
341 /* Put the declaration on the list. The list of declarations is in reverse
342 order. The list will be reversed later. We don't do this for global
343 variables. Also, don't put TYPE_DECLs for UNCONSTRAINED_ARRAY_TYPE into
344 the list. They will cause trouble with the debugger and aren't needed
346 if (!global_bindings_p ()
347 && (TREE_CODE (decl) != TYPE_DECL
348 || TREE_CODE (TREE_TYPE (decl)) != UNCONSTRAINED_ARRAY_TYPE))
350 TREE_CHAIN (decl) = BLOCK_VARS (current_binding_level->block);
351 BLOCK_VARS (current_binding_level->block) = decl;
354 /* For the declaration of a type, set its name if it either is not already
355 set, was set to an IDENTIFIER_NODE, indicating an internal name,
356 or if the previous type name was not derived from a source name.
357 We'd rather have the type named with a real name and all the pointer
358 types to the same object have the same POINTER_TYPE node. Code in this
359 function in c-decl.c makes a copy of the type node here, but that may
360 cause us trouble with incomplete types, so let's not try it (at least
363 if (TREE_CODE (decl) == TYPE_DECL
365 && (!TYPE_NAME (TREE_TYPE (decl))
366 || TREE_CODE (TYPE_NAME (TREE_TYPE (decl))) == IDENTIFIER_NODE
367 || (TREE_CODE (TYPE_NAME (TREE_TYPE (decl))) == TYPE_DECL
368 && DECL_ARTIFICIAL (TYPE_NAME (TREE_TYPE (decl)))
369 && !DECL_ARTIFICIAL (decl))))
370 TYPE_NAME (TREE_TYPE (decl)) = decl;
372 /* if (TREE_CODE (decl) != CONST_DECL)
373 rest_of_decl_compilation (decl, global_bindings_p (), 0); */
376 /* Do little here. Set up the standard declarations later after the
377 front end has been run. */
380 gnat_init_decl_processing (void)
384 /* Make the binding_level structure for global names. */
385 current_function_decl = 0;
386 current_binding_level = 0;
387 free_binding_level = 0;
390 build_common_tree_nodes (true, true);
392 /* In Ada, we use a signed type for SIZETYPE. Use the signed type
393 corresponding to the size of Pmode. In most cases when ptr_mode and
394 Pmode differ, C will use the width of ptr_mode as sizetype. But we get
395 far better code using the width of Pmode. Make this here since we need
396 this before we can expand the GNAT types. */
397 size_type_node = gnat_type_for_size (GET_MODE_BITSIZE (Pmode), 0);
398 set_sizetype (size_type_node);
399 build_common_tree_nodes_2 (0);
401 /* Give names and make TYPE_DECLs for common types. */
402 gnat_pushdecl (build_decl (TYPE_DECL, get_identifier (SIZE_TYPE), sizetype),
404 gnat_pushdecl (build_decl (TYPE_DECL, get_identifier ("integer"),
407 gnat_pushdecl (build_decl (TYPE_DECL, get_identifier ("unsigned char"),
410 gnat_pushdecl (build_decl (TYPE_DECL, get_identifier ("long integer"),
411 long_integer_type_node),
414 ptr_void_type_node = build_pointer_type (void_type_node);
416 gnat_install_builtins ();
419 /* Install the builtin functions the middle-end needs. */
422 gnat_install_builtins ()
424 /* Builtins used by generic optimizers. */
425 build_common_builtin_nodes ();
427 /* Target specific builtins, such as the AltiVec family on ppc. */
428 targetm.init_builtins ();
431 /* Create the predefined scalar types such as `integer_type_node' needed
432 in the gcc back-end and initialize the global binding level. */
435 init_gigi_decls (tree long_long_float_type, tree exception_type)
440 /* Set the types that GCC and Gigi use from the front end. We would like
441 to do this for char_type_node, but it needs to correspond to the C
443 if (TREE_CODE (TREE_TYPE (long_long_float_type)) == INTEGER_TYPE)
445 /* In this case, the builtin floating point types are VAX float,
446 so make up a type for use. */
447 longest_float_type_node = make_node (REAL_TYPE);
448 TYPE_PRECISION (longest_float_type_node) = LONG_DOUBLE_TYPE_SIZE;
449 layout_type (longest_float_type_node);
450 create_type_decl (get_identifier ("longest float type"),
451 longest_float_type_node, NULL, false, true, Empty);
454 longest_float_type_node = TREE_TYPE (long_long_float_type);
456 except_type_node = TREE_TYPE (exception_type);
458 unsigned_type_node = gnat_type_for_size (INT_TYPE_SIZE, 1);
459 create_type_decl (get_identifier ("unsigned int"), unsigned_type_node,
460 NULL, false, true, Empty);
462 void_type_decl_node = create_type_decl (get_identifier ("void"),
463 void_type_node, NULL, false, true,
466 void_ftype = build_function_type (void_type_node, NULL_TREE);
467 ptr_void_ftype = build_pointer_type (void_ftype);
469 /* Now declare runtime functions. */
470 endlink = tree_cons (NULL_TREE, void_type_node, NULL_TREE);
472 /* malloc is a function declaration tree for a function to allocate
474 malloc_decl = create_subprog_decl (get_identifier ("__gnat_malloc"),
476 build_function_type (ptr_void_type_node,
477 tree_cons (NULL_TREE,
480 NULL_TREE, false, true, true, NULL,
483 /* free is a function declaration tree for a function to free memory. */
485 = create_subprog_decl (get_identifier ("__gnat_free"), NULL_TREE,
486 build_function_type (void_type_node,
487 tree_cons (NULL_TREE,
490 NULL_TREE, false, true, true, NULL, Empty);
492 /* Make the types and functions used for exception processing. */
494 = build_array_type (gnat_type_for_mode (Pmode, 0),
495 build_index_type (build_int_cst (NULL_TREE, 5)));
496 create_type_decl (get_identifier ("JMPBUF_T"), jmpbuf_type, NULL,
498 jmpbuf_ptr_type = build_pointer_type (jmpbuf_type);
500 /* Functions to get and set the jumpbuf pointer for the current thread. */
502 = create_subprog_decl
503 (get_identifier ("system__soft_links__get_jmpbuf_address_soft"),
504 NULL_TREE, build_function_type (jmpbuf_ptr_type, NULL_TREE),
505 NULL_TREE, false, true, true, NULL, Empty);
508 = create_subprog_decl
509 (get_identifier ("system__soft_links__set_jmpbuf_address_soft"),
511 build_function_type (void_type_node,
512 tree_cons (NULL_TREE, jmpbuf_ptr_type, endlink)),
513 NULL_TREE, false, true, true, NULL, Empty);
515 /* Function to get the current exception. */
517 = create_subprog_decl
518 (get_identifier ("system__soft_links__get_gnat_exception"),
520 build_function_type (build_pointer_type (except_type_node), NULL_TREE),
521 NULL_TREE, false, true, true, NULL, Empty);
523 /* Functions that raise exceptions. */
525 = create_subprog_decl
526 (get_identifier ("__gnat_raise_nodefer_with_msg"), NULL_TREE,
527 build_function_type (void_type_node,
528 tree_cons (NULL_TREE,
529 build_pointer_type (except_type_node),
531 NULL_TREE, false, true, true, NULL, Empty);
533 /* Dummy objects to materialize "others" and "all others" in the exception
534 tables. These are exported by a-exexpr.adb, so see this unit for the
538 = create_var_decl (get_identifier ("OTHERS"),
539 get_identifier ("__gnat_others_value"),
540 integer_type_node, 0, 1, 0, 1, 1, 0, Empty);
543 = create_var_decl (get_identifier ("ALL_OTHERS"),
544 get_identifier ("__gnat_all_others_value"),
545 integer_type_node, 0, 1, 0, 1, 1, 0, Empty);
547 /* Hooks to call when entering/leaving an exception handler. */
549 = create_subprog_decl (get_identifier ("__gnat_begin_handler"), NULL_TREE,
550 build_function_type (void_type_node,
551 tree_cons (NULL_TREE,
554 NULL_TREE, false, true, true, NULL, Empty);
557 = create_subprog_decl (get_identifier ("__gnat_end_handler"), NULL_TREE,
558 build_function_type (void_type_node,
559 tree_cons (NULL_TREE,
562 NULL_TREE, false, true, true, NULL, Empty);
564 /* If in no exception handlers mode, all raise statements are redirected to
565 __gnat_last_chance_handler. No need to redefine raise_nodefer_decl, since
566 this procedure will never be called in this mode. */
567 if (No_Exception_Handlers_Set ())
570 = create_subprog_decl
571 (get_identifier ("__gnat_last_chance_handler"), NULL_TREE,
572 build_function_type (void_type_node,
573 tree_cons (NULL_TREE,
574 build_pointer_type (char_type_node),
575 tree_cons (NULL_TREE,
578 NULL_TREE, false, true, true, NULL, Empty);
580 for (i = 0; i < ARRAY_SIZE (gnat_raise_decls); i++)
581 gnat_raise_decls[i] = decl;
584 /* Otherwise, make one decl for each exception reason. */
585 for (i = 0; i < ARRAY_SIZE (gnat_raise_decls); i++)
589 sprintf (name, "__gnat_rcheck_%.2d", i);
591 = create_subprog_decl
592 (get_identifier (name), NULL_TREE,
593 build_function_type (void_type_node,
594 tree_cons (NULL_TREE,
597 tree_cons (NULL_TREE,
600 NULL_TREE, false, true, true, NULL, Empty);
603 /* Indicate that these never return. */
604 TREE_THIS_VOLATILE (raise_nodefer_decl) = 1;
605 TREE_SIDE_EFFECTS (raise_nodefer_decl) = 1;
606 TREE_TYPE (raise_nodefer_decl)
607 = build_qualified_type (TREE_TYPE (raise_nodefer_decl),
610 for (i = 0; i < ARRAY_SIZE (gnat_raise_decls); i++)
612 TREE_THIS_VOLATILE (gnat_raise_decls[i]) = 1;
613 TREE_SIDE_EFFECTS (gnat_raise_decls[i]) = 1;
614 TREE_TYPE (gnat_raise_decls[i])
615 = build_qualified_type (TREE_TYPE (gnat_raise_decls[i]),
619 /* setjmp returns an integer and has one operand, which is a pointer to
622 = create_subprog_decl
623 (get_identifier ("__builtin_setjmp"), NULL_TREE,
624 build_function_type (integer_type_node,
625 tree_cons (NULL_TREE, jmpbuf_ptr_type, endlink)),
626 NULL_TREE, false, true, true, NULL, Empty);
628 DECL_BUILT_IN_CLASS (setjmp_decl) = BUILT_IN_NORMAL;
629 DECL_FUNCTION_CODE (setjmp_decl) = BUILT_IN_SETJMP;
631 /* update_setjmp_buf updates a setjmp buffer from the current stack pointer
633 update_setjmp_buf_decl
634 = create_subprog_decl
635 (get_identifier ("__builtin_update_setjmp_buf"), NULL_TREE,
636 build_function_type (void_type_node,
637 tree_cons (NULL_TREE, jmpbuf_ptr_type, endlink)),
638 NULL_TREE, false, true, true, NULL, Empty);
640 DECL_BUILT_IN_CLASS (update_setjmp_buf_decl) = BUILT_IN_NORMAL;
641 DECL_FUNCTION_CODE (update_setjmp_buf_decl) = BUILT_IN_UPDATE_SETJMP_BUF;
643 main_identifier_node = get_identifier ("main");
646 /* Given a record type (RECORD_TYPE) and a chain of FIELD_DECL nodes
647 (FIELDLIST), finish constructing the record or union type. If HAS_REP is
648 true, this record has a rep clause; don't call layout_type but merely set
649 the size and alignment ourselves. If DEFER_DEBUG is true, do not call
650 the debugging routines on this type; it will be done later. */
653 finish_record_type (tree record_type, tree fieldlist, bool has_rep,
656 enum tree_code code = TREE_CODE (record_type);
657 tree ada_size = bitsize_zero_node;
658 tree size = bitsize_zero_node;
659 bool var_size = false;
660 bool had_size = TYPE_SIZE (record_type) != 0;
661 bool had_size_unit = TYPE_SIZE_UNIT (record_type) != 0;
664 TYPE_FIELDS (record_type) = fieldlist;
665 TYPE_STUB_DECL (record_type)
666 = build_decl (TYPE_DECL, NULL_TREE, record_type);
668 /* We don't need both the typedef name and the record name output in
669 the debugging information, since they are the same. */
670 DECL_ARTIFICIAL (TYPE_STUB_DECL (record_type)) = 1;
672 /* Globally initialize the record first. If this is a rep'ed record,
673 that just means some initializations; otherwise, layout the record. */
677 TYPE_ALIGN (record_type) = MAX (BITS_PER_UNIT, TYPE_ALIGN (record_type));
678 TYPE_MODE (record_type) = BLKmode;
681 TYPE_SIZE_UNIT (record_type) = size_zero_node;
683 TYPE_SIZE (record_type) = bitsize_zero_node;
685 /* For all-repped records with a size specified, lay the QUAL_UNION_TYPE
686 out just like a UNION_TYPE, since the size will be fixed. */
687 else if (code == QUAL_UNION_TYPE)
692 /* Ensure there isn't a size already set. There can be in an error
693 case where there is a rep clause but all fields have errors and
694 no longer have a position. */
695 TYPE_SIZE (record_type) = 0;
696 layout_type (record_type);
699 /* At this point, the position and size of each field is known. It was
700 either set before entry by a rep clause, or by laying out the type above.
702 We now run a pass over the fields (in reverse order for QUAL_UNION_TYPEs)
703 to compute the Ada size; the GCC size and alignment (for rep'ed records
704 that are not padding types); and the mode (for rep'ed records). We also
705 clear the DECL_BIT_FIELD indication for the cases we know have not been
706 handled yet, and adjust DECL_NONADDRESSABLE_P accordingly. */
708 if (code == QUAL_UNION_TYPE)
709 fieldlist = nreverse (fieldlist);
711 for (field = fieldlist; field; field = TREE_CHAIN (field))
713 tree pos = bit_position (field);
715 tree type = TREE_TYPE (field);
716 tree this_size = DECL_SIZE (field);
717 tree this_ada_size = DECL_SIZE (field);
719 /* We need to make an XVE/XVU record if any field has variable size,
720 whether or not the record does. For example, if we have a union,
721 it may be that all fields, rounded up to the alignment, have the
722 same size, in which case we'll use that size. But the debug
723 output routines (except Dwarf2) won't be able to output the fields,
724 so we need to make the special record. */
725 if (TREE_CODE (this_size) != INTEGER_CST)
728 if ((TREE_CODE (type) == RECORD_TYPE || TREE_CODE (type) == UNION_TYPE
729 || TREE_CODE (type) == QUAL_UNION_TYPE)
730 && !TYPE_IS_FAT_POINTER_P (type)
731 && !TYPE_CONTAINS_TEMPLATE_P (type)
732 && TYPE_ADA_SIZE (type))
733 this_ada_size = TYPE_ADA_SIZE (type);
735 /* Clear DECL_BIT_FIELD for the cases layout_decl does not handle. */
736 if (DECL_BIT_FIELD (field) && !STRICT_ALIGNMENT
737 && value_factor_p (pos, BITS_PER_UNIT)
738 && operand_equal_p (this_size, TYPE_SIZE (type), 0))
739 DECL_BIT_FIELD (field) = 0;
741 /* If we still have DECL_BIT_FIELD set at this point, we know the field
742 is technically not addressable. Except that it can actually be
743 addressed if the field is BLKmode and happens to be properly
745 DECL_NONADDRESSABLE_P (field)
746 |= DECL_BIT_FIELD (field) && DECL_MODE (field) != BLKmode;
748 if (has_rep && !DECL_BIT_FIELD (field))
749 TYPE_ALIGN (record_type)
750 = MAX (TYPE_ALIGN (record_type), DECL_ALIGN (field));
755 ada_size = size_binop (MAX_EXPR, ada_size, this_ada_size);
756 size = size_binop (MAX_EXPR, size, this_size);
759 case QUAL_UNION_TYPE:
761 = fold (build3 (COND_EXPR, bitsizetype, DECL_QUALIFIER (field),
762 this_ada_size, ada_size));
763 size = fold (build3 (COND_EXPR, bitsizetype, DECL_QUALIFIER (field),
768 /* Since we know here that all fields are sorted in order of
769 increasing bit position, the size of the record is one
770 higher than the ending bit of the last field processed
771 unless we have a rep clause, since in that case we might
772 have a field outside a QUAL_UNION_TYPE that has a higher ending
773 position. So use a MAX in that case. Also, if this field is a
774 QUAL_UNION_TYPE, we need to take into account the previous size in
775 the case of empty variants. */
777 = merge_sizes (ada_size, pos, this_ada_size,
778 TREE_CODE (type) == QUAL_UNION_TYPE, has_rep);
779 size = merge_sizes (size, pos, this_size,
780 TREE_CODE (type) == QUAL_UNION_TYPE, has_rep);
788 if (code == QUAL_UNION_TYPE)
789 nreverse (fieldlist);
791 /* If this is a padding record, we never want to make the size smaller than
792 what was specified in it, if any. */
793 if (TREE_CODE (record_type) == RECORD_TYPE
794 && TYPE_IS_PADDING_P (record_type) && TYPE_SIZE (record_type))
795 size = TYPE_SIZE (record_type);
797 /* Now set any of the values we've just computed that apply. */
798 if (!TYPE_IS_FAT_POINTER_P (record_type)
799 && !TYPE_CONTAINS_TEMPLATE_P (record_type))
800 SET_TYPE_ADA_SIZE (record_type, ada_size);
805 = (had_size_unit ? TYPE_SIZE_UNIT (record_type)
806 : convert (sizetype, size_binop (CEIL_DIV_EXPR, size,
807 bitsize_unit_node)));
809 TYPE_SIZE (record_type)
810 = variable_size (round_up (size, TYPE_ALIGN (record_type)));
811 TYPE_SIZE_UNIT (record_type)
812 = variable_size (round_up (size_unit,
813 TYPE_ALIGN (record_type) / BITS_PER_UNIT));
815 compute_record_mode (record_type);
819 write_record_type_debug_info (record_type);
822 /* Output the debug information associated to a record type. */
825 write_record_type_debug_info (tree record_type)
827 tree fieldlist = TYPE_FIELDS (record_type);
829 bool var_size = false;
831 for (field = fieldlist; field; field = TREE_CHAIN (field))
833 /* We need to make an XVE/XVU record if any field has variable size,
834 whether or not the record does. For example, if we have a union,
835 it may be that all fields, rounded up to the alignment, have the
836 same size, in which case we'll use that size. But the debug
837 output routines (except Dwarf2) won't be able to output the fields,
838 so we need to make the special record. */
839 if (TREE_CODE (DECL_SIZE (field)) != INTEGER_CST)
846 /* If this record is of variable size, rename it so that the
847 debugger knows it is and make a new, parallel, record
848 that tells the debugger how the record is laid out. See
849 exp_dbug.ads. But don't do this for records that are padding
850 since they confuse GDB. */
852 && !(TREE_CODE (record_type) == RECORD_TYPE
853 && TYPE_IS_PADDING_P (record_type)))
856 = make_node (TREE_CODE (record_type) == QUAL_UNION_TYPE
857 ? UNION_TYPE : TREE_CODE (record_type));
858 tree orig_name = TYPE_NAME (record_type);
860 = (TREE_CODE (orig_name) == TYPE_DECL ? DECL_NAME (orig_name)
863 = concat_id_with_name (orig_id,
864 TREE_CODE (record_type) == QUAL_UNION_TYPE
866 tree last_pos = bitsize_zero_node;
868 tree prev_old_field = 0;
870 TYPE_NAME (new_record_type) = new_id;
871 TYPE_ALIGN (new_record_type) = BIGGEST_ALIGNMENT;
872 TYPE_STUB_DECL (new_record_type)
873 = build_decl (TYPE_DECL, NULL_TREE, new_record_type);
874 DECL_ARTIFICIAL (TYPE_STUB_DECL (new_record_type)) = 1;
875 DECL_IGNORED_P (TYPE_STUB_DECL (new_record_type))
876 = DECL_IGNORED_P (TYPE_STUB_DECL (record_type));
877 TYPE_SIZE (new_record_type) = size_int (TYPE_ALIGN (record_type));
878 TYPE_SIZE_UNIT (new_record_type)
879 = size_int (TYPE_ALIGN (record_type) / BITS_PER_UNIT);
881 /* Now scan all the fields, replacing each field with a new
882 field corresponding to the new encoding. */
883 for (old_field = TYPE_FIELDS (record_type); old_field;
884 old_field = TREE_CHAIN (old_field))
886 tree field_type = TREE_TYPE (old_field);
887 tree field_name = DECL_NAME (old_field);
889 tree curpos = bit_position (old_field);
891 unsigned int align = 0;
894 /* See how the position was modified from the last position.
896 There are two basic cases we support: a value was added
897 to the last position or the last position was rounded to
898 a boundary and they something was added. Check for the
899 first case first. If not, see if there is any evidence
900 of rounding. If so, round the last position and try
903 If this is a union, the position can be taken as zero. */
905 if (TREE_CODE (new_record_type) == UNION_TYPE)
906 pos = bitsize_zero_node, align = 0;
908 pos = compute_related_constant (curpos, last_pos);
910 if (!pos && TREE_CODE (curpos) == MULT_EXPR
911 && TREE_CODE (TREE_OPERAND (curpos, 1)) == INTEGER_CST)
913 align = TREE_INT_CST_LOW (TREE_OPERAND (curpos, 1));
914 pos = compute_related_constant (curpos,
915 round_up (last_pos, align));
917 else if (!pos && TREE_CODE (curpos) == PLUS_EXPR
918 && TREE_CODE (TREE_OPERAND (curpos, 1)) == INTEGER_CST
919 && TREE_CODE (TREE_OPERAND (curpos, 0)) == MULT_EXPR
920 && host_integerp (TREE_OPERAND
921 (TREE_OPERAND (curpos, 0), 1),
926 (TREE_OPERAND (TREE_OPERAND (curpos, 0), 1), 1);
927 pos = compute_related_constant (curpos,
928 round_up (last_pos, align));
930 else if (potential_alignment_gap (prev_old_field, old_field,
933 align = TYPE_ALIGN (field_type);
934 pos = compute_related_constant (curpos,
935 round_up (last_pos, align));
938 /* If we can't compute a position, set it to zero.
940 ??? We really should abort here, but it's too much work
941 to get this correct for all cases. */
944 pos = bitsize_zero_node;
946 /* See if this type is variable-size and make a new type
947 and indicate the indirection if so. */
948 if (TREE_CODE (DECL_SIZE (old_field)) != INTEGER_CST)
950 field_type = build_pointer_type (field_type);
954 /* Make a new field name, if necessary. */
955 if (var || align != 0)
960 sprintf (suffix, "XV%c%u", var ? 'L' : 'A',
961 align / BITS_PER_UNIT);
963 strcpy (suffix, "XVL");
965 field_name = concat_id_with_name (field_name, suffix);
968 new_field = create_field_decl (field_name, field_type,
970 DECL_SIZE (old_field), pos, 0);
971 TREE_CHAIN (new_field) = TYPE_FIELDS (new_record_type);
972 TYPE_FIELDS (new_record_type) = new_field;
974 /* If old_field is a QUAL_UNION_TYPE, take its size as being
975 zero. The only time it's not the last field of the record
976 is when there are other components at fixed positions after
977 it (meaning there was a rep clause for every field) and we
978 want to be able to encode them. */
979 last_pos = size_binop (PLUS_EXPR, bit_position (old_field),
980 (TREE_CODE (TREE_TYPE (old_field))
983 : DECL_SIZE (old_field));
984 prev_old_field = old_field;
987 TYPE_FIELDS (new_record_type)
988 = nreverse (TYPE_FIELDS (new_record_type));
990 rest_of_type_compilation (new_record_type, global_bindings_p ());
993 rest_of_type_compilation (record_type, global_bindings_p ());
996 /* Utility function of above to merge LAST_SIZE, the previous size of a record
997 with FIRST_BIT and SIZE that describe a field. SPECIAL is nonzero
998 if this represents a QUAL_UNION_TYPE in which case we must look for
999 COND_EXPRs and replace a value of zero with the old size. If HAS_REP
1000 is nonzero, we must take the MAX of the end position of this field
1001 with LAST_SIZE. In all other cases, we use FIRST_BIT plus SIZE.
1003 We return an expression for the size. */
1006 merge_sizes (tree last_size, tree first_bit, tree size, bool special,
1009 tree type = TREE_TYPE (last_size);
1012 if (!special || TREE_CODE (size) != COND_EXPR)
1014 new = size_binop (PLUS_EXPR, first_bit, size);
1016 new = size_binop (MAX_EXPR, last_size, new);
1020 new = fold (build3 (COND_EXPR, type, TREE_OPERAND (size, 0),
1021 integer_zerop (TREE_OPERAND (size, 1))
1022 ? last_size : merge_sizes (last_size, first_bit,
1023 TREE_OPERAND (size, 1),
1025 integer_zerop (TREE_OPERAND (size, 2))
1026 ? last_size : merge_sizes (last_size, first_bit,
1027 TREE_OPERAND (size, 2),
1030 /* We don't need any NON_VALUE_EXPRs and they can confuse us (especially
1031 when fed through substitute_in_expr) into thinking that a constant
1032 size is not constant. */
1033 while (TREE_CODE (new) == NON_LVALUE_EXPR)
1034 new = TREE_OPERAND (new, 0);
1039 /* Utility function of above to see if OP0 and OP1, both of SIZETYPE, are
1040 related by the addition of a constant. Return that constant if so. */
1043 compute_related_constant (tree op0, tree op1)
1045 tree op0_var, op1_var;
1046 tree op0_con = split_plus (op0, &op0_var);
1047 tree op1_con = split_plus (op1, &op1_var);
1048 tree result = size_binop (MINUS_EXPR, op0_con, op1_con);
1050 if (operand_equal_p (op0_var, op1_var, 0))
1052 else if (operand_equal_p (op0, size_binop (PLUS_EXPR, op1_var, result), 0))
1058 /* Utility function of above to split a tree OP which may be a sum, into a
1059 constant part, which is returned, and a variable part, which is stored
1060 in *PVAR. *PVAR may be bitsize_zero_node. All operations must be of
1064 split_plus (tree in, tree *pvar)
1066 /* Strip NOPS in order to ease the tree traversal and maximize the
1067 potential for constant or plus/minus discovery. We need to be careful
1068 to always return and set *pvar to bitsizetype trees, but it's worth
1072 *pvar = convert (bitsizetype, in);
1074 if (TREE_CODE (in) == INTEGER_CST)
1076 *pvar = bitsize_zero_node;
1077 return convert (bitsizetype, in);
1079 else if (TREE_CODE (in) == PLUS_EXPR || TREE_CODE (in) == MINUS_EXPR)
1081 tree lhs_var, rhs_var;
1082 tree lhs_con = split_plus (TREE_OPERAND (in, 0), &lhs_var);
1083 tree rhs_con = split_plus (TREE_OPERAND (in, 1), &rhs_var);
1085 if (lhs_var == TREE_OPERAND (in, 0)
1086 && rhs_var == TREE_OPERAND (in, 1))
1087 return bitsize_zero_node;
1089 *pvar = size_binop (TREE_CODE (in), lhs_var, rhs_var);
1090 return size_binop (TREE_CODE (in), lhs_con, rhs_con);
1093 return bitsize_zero_node;
1096 /* Return a FUNCTION_TYPE node. RETURN_TYPE is the type returned by the
1097 subprogram. If it is void_type_node, then we are dealing with a procedure,
1098 otherwise we are dealing with a function. PARAM_DECL_LIST is a list of
1099 PARM_DECL nodes that are the subprogram arguments. CICO_LIST is the
1100 copy-in/copy-out list to be stored into TYPE_CICO_LIST.
1101 RETURNS_UNCONSTRAINED is nonzero if the function returns an unconstrained
1102 object. RETURNS_BY_REF is nonzero if the function returns by reference.
1103 RETURNS_WITH_DSP is nonzero if the function is to return with a
1104 depressed stack pointer. RETURNS_BY_TARGET_PTR is true if the function
1105 is to be passed (as its first parameter) the address of the place to copy
1109 create_subprog_type (tree return_type, tree param_decl_list, tree cico_list,
1110 bool returns_unconstrained, bool returns_by_ref,
1111 bool returns_with_dsp, bool returns_by_target_ptr)
1113 /* A chain of TREE_LIST nodes whose TREE_VALUEs are the data type nodes of
1114 the subprogram formal parameters. This list is generated by traversing the
1115 input list of PARM_DECL nodes. */
1116 tree param_type_list = NULL;
1120 for (param_decl = param_decl_list; param_decl;
1121 param_decl = TREE_CHAIN (param_decl))
1122 param_type_list = tree_cons (NULL_TREE, TREE_TYPE (param_decl),
1125 /* The list of the function parameter types has to be terminated by the void
1126 type to signal to the back-end that we are not dealing with a variable
1127 parameter subprogram, but that the subprogram has a fixed number of
1129 param_type_list = tree_cons (NULL_TREE, void_type_node, param_type_list);
1131 /* The list of argument types has been created in reverse
1133 param_type_list = nreverse (param_type_list);
1135 type = build_function_type (return_type, param_type_list);
1137 /* TYPE may have been shared since GCC hashes types. If it has a CICO_LIST
1138 or the new type should, make a copy of TYPE. Likewise for
1139 RETURNS_UNCONSTRAINED and RETURNS_BY_REF. */
1140 if (TYPE_CI_CO_LIST (type) || cico_list
1141 || TYPE_RETURNS_UNCONSTRAINED_P (type) != returns_unconstrained
1142 || TYPE_RETURNS_BY_REF_P (type) != returns_by_ref
1143 || TYPE_RETURNS_BY_TARGET_PTR_P (type) != returns_by_target_ptr)
1144 type = copy_type (type);
1146 TYPE_CI_CO_LIST (type) = cico_list;
1147 TYPE_RETURNS_UNCONSTRAINED_P (type) = returns_unconstrained;
1148 TYPE_RETURNS_STACK_DEPRESSED (type) = returns_with_dsp;
1149 TYPE_RETURNS_BY_REF_P (type) = returns_by_ref;
1150 TYPE_RETURNS_BY_TARGET_PTR_P (type) = returns_by_target_ptr;
1154 /* Return a copy of TYPE but safe to modify in any way. */
1157 copy_type (tree type)
1159 tree new = copy_node (type);
1161 /* copy_node clears this field instead of copying it, because it is
1162 aliased with TREE_CHAIN. */
1163 TYPE_STUB_DECL (new) = TYPE_STUB_DECL (type);
1165 TYPE_POINTER_TO (new) = 0;
1166 TYPE_REFERENCE_TO (new) = 0;
1167 TYPE_MAIN_VARIANT (new) = new;
1168 TYPE_NEXT_VARIANT (new) = 0;
1173 /* Return an INTEGER_TYPE of SIZETYPE with range MIN to MAX and whose
1174 TYPE_INDEX_TYPE is INDEX. */
1177 create_index_type (tree min, tree max, tree index)
1179 /* First build a type for the desired range. */
1180 tree type = build_index_2_type (min, max);
1182 /* If this type has the TYPE_INDEX_TYPE we want, return it. Otherwise, if it
1183 doesn't have TYPE_INDEX_TYPE set, set it to INDEX. If TYPE_INDEX_TYPE
1184 is set, but not to INDEX, make a copy of this type with the requested
1185 index type. Note that we have no way of sharing these types, but that's
1186 only a small hole. */
1187 if (TYPE_INDEX_TYPE (type) == index)
1189 else if (TYPE_INDEX_TYPE (type))
1190 type = copy_type (type);
1192 SET_TYPE_INDEX_TYPE (type, index);
1193 create_type_decl (NULL_TREE, type, NULL, true, false, Empty);
1197 /* Return a TYPE_DECL node. TYPE_NAME gives the name of the type (a character
1198 string) and TYPE is a ..._TYPE node giving its data type.
1199 ARTIFICIAL_P is true if this is a declaration that was generated
1200 by the compiler. DEBUG_INFO_P is true if we need to write debugging
1201 information about this type. GNAT_NODE is used for the position of
1205 create_type_decl (tree type_name, tree type, struct attrib *attr_list,
1206 bool artificial_p, bool debug_info_p, Node_Id gnat_node)
1208 tree type_decl = build_decl (TYPE_DECL, type_name, type);
1209 enum tree_code code = TREE_CODE (type);
1211 DECL_ARTIFICIAL (type_decl) = artificial_p;
1213 process_attributes (type_decl, attr_list);
1215 /* Pass type declaration information to the debugger unless this is an
1216 UNCONSTRAINED_ARRAY_TYPE, which the debugger does not support,
1217 and ENUMERAL_TYPE or RECORD_TYPE which is handled separately, or
1218 type for which debugging information was not requested. */
1219 if (code == UNCONSTRAINED_ARRAY_TYPE || ! debug_info_p)
1220 DECL_IGNORED_P (type_decl) = 1;
1221 if (code == UNCONSTRAINED_ARRAY_TYPE || TYPE_IS_DUMMY_P (type)
1223 DECL_IGNORED_P (type_decl) = 1;
1224 else if (code != ENUMERAL_TYPE && code != RECORD_TYPE
1225 && !((code == POINTER_TYPE || code == REFERENCE_TYPE)
1226 && TYPE_IS_DUMMY_P (TREE_TYPE (type))))
1227 rest_of_decl_compilation (type_decl, global_bindings_p (), 0);
1229 if (!TYPE_IS_DUMMY_P (type))
1230 gnat_pushdecl (type_decl, gnat_node);
1235 /* Returns a GCC VAR_DECL node. VAR_NAME gives the name of the variable.
1236 ASM_NAME is its assembler name (if provided). TYPE is its data type
1237 (a GCC ..._TYPE node). VAR_INIT is the GCC tree for an optional initial
1238 expression; NULL_TREE if none.
1240 CONST_FLAG is true if this variable is constant.
1242 PUBLIC_FLAG is true if this definition is to be made visible outside of
1243 the current compilation unit. This flag should be set when processing the
1244 variable definitions in a package specification. EXTERN_FLAG is nonzero
1245 when processing an external variable declaration (as opposed to a
1246 definition: no storage is to be allocated for the variable here).
1248 STATIC_FLAG is only relevant when not at top level. In that case
1249 it indicates whether to always allocate storage to the variable.
1251 GNAT_NODE is used for the position of the decl. */
1254 create_var_decl (tree var_name, tree asm_name, tree type, tree var_init,
1255 bool const_flag, bool public_flag, bool extern_flag,
1256 bool static_flag, struct attrib *attr_list, Node_Id gnat_node)
1261 : (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (var_init))
1262 && (global_bindings_p () || static_flag
1263 ? 0 != initializer_constant_valid_p (var_init,
1264 TREE_TYPE (var_init))
1265 : TREE_CONSTANT (var_init))));
1267 = build_decl ((const_flag && init_const
1268 /* Only make a CONST_DECL for sufficiently-small objects.
1269 We consider complex double "sufficiently-small" */
1270 && TYPE_SIZE (type) != 0
1271 && host_integerp (TYPE_SIZE_UNIT (type), 1)
1272 && 0 >= compare_tree_int (TYPE_SIZE_UNIT (type),
1273 GET_MODE_SIZE (DCmode)))
1274 ? CONST_DECL : VAR_DECL, var_name, type);
1276 /* If this is external, throw away any initializations unless this is a
1277 CONST_DECL (meaning we have a constant); they will be done elsewhere.
1278 If we are defining a global here, leave a constant initialization and
1279 save any variable elaborations for the elaboration routine. If we are
1280 just annotating types, throw away the initialization if it isn't a
1282 if ((extern_flag && TREE_CODE (var_decl) != CONST_DECL)
1283 || (type_annotate_only && var_init && !TREE_CONSTANT (var_init)))
1284 var_init = NULL_TREE;
1286 /* At the global level, an initializer requiring code to be generated
1287 produces elaboration statements. Check that such statements are allowed,
1288 that is, not violating a No_Elaboration_Code restriction. */
1289 if (global_bindings_p () && var_init != 0 && ! init_const)
1290 Check_Elaboration_Code_Allowed (gnat_node);
1292 /* Ada doesn't feature Fortran-like COMMON variables so we shouldn't
1293 try to fiddle with DECL_COMMON. However, on platforms that don't
1294 support global BSS sections, uninitialized global variables would
1295 go in DATA instead, thus increasing the size of the executable. */
1297 && TREE_CODE (var_decl) == VAR_DECL
1298 && !have_global_bss_p ())
1299 DECL_COMMON (var_decl) = 1;
1300 DECL_INITIAL (var_decl) = var_init;
1301 TREE_READONLY (var_decl) = const_flag;
1302 DECL_EXTERNAL (var_decl) = extern_flag;
1303 TREE_PUBLIC (var_decl) = public_flag || extern_flag;
1304 TREE_CONSTANT (var_decl) = TREE_CODE (var_decl) == CONST_DECL;
1305 TREE_THIS_VOLATILE (var_decl) = TREE_SIDE_EFFECTS (var_decl)
1306 = TYPE_VOLATILE (type);
1308 /* If it's public and not external, always allocate storage for it.
1309 At the global binding level we need to allocate static storage for the
1310 variable if and only if it's not external. If we are not at the top level
1311 we allocate automatic storage unless requested not to. */
1312 TREE_STATIC (var_decl)
1313 = public_flag || (global_bindings_p () ? !extern_flag : static_flag);
1315 if (asm_name && VAR_OR_FUNCTION_DECL_P (var_decl))
1316 SET_DECL_ASSEMBLER_NAME (var_decl, asm_name);
1318 process_attributes (var_decl, attr_list);
1320 /* Add this decl to the current binding level. */
1321 gnat_pushdecl (var_decl, gnat_node);
1323 if (TREE_SIDE_EFFECTS (var_decl))
1324 TREE_ADDRESSABLE (var_decl) = 1;
1326 if (TREE_CODE (var_decl) != CONST_DECL)
1327 rest_of_decl_compilation (var_decl, global_bindings_p (), 0);
1329 /* expand CONST_DECLs to set their MODE, ALIGN, SIZE and SIZE_UNIT,
1330 which we need for later back-annotations. */
1331 expand_decl (var_decl);
1336 /* Returns a FIELD_DECL node. FIELD_NAME the field name, FIELD_TYPE is its
1337 type, and RECORD_TYPE is the type of the parent. PACKED is nonzero if
1338 this field is in a record type with a "pragma pack". If SIZE is nonzero
1339 it is the specified size for this field. If POS is nonzero, it is the bit
1340 position. If ADDRESSABLE is nonzero, it means we are allowed to take
1341 the address of this field for aliasing purposes. If it is negative, we
1342 should not make a bitfield, which is used by make_aligning_type. */
1345 create_field_decl (tree field_name, tree field_type, tree record_type,
1346 int packed, tree size, tree pos, int addressable)
1348 tree field_decl = build_decl (FIELD_DECL, field_name, field_type);
1350 DECL_CONTEXT (field_decl) = record_type;
1351 TREE_READONLY (field_decl) = TYPE_READONLY (field_type);
1353 /* If FIELD_TYPE is BLKmode, we must ensure this is aligned to at least a
1354 byte boundary since GCC cannot handle less-aligned BLKmode bitfields. */
1355 if (packed && TYPE_MODE (field_type) == BLKmode)
1356 DECL_ALIGN (field_decl) = BITS_PER_UNIT;
1358 /* If a size is specified, use it. Otherwise, if the record type is packed
1359 compute a size to use, which may differ from the object's natural size.
1360 We always set a size in this case to trigger the checks for bitfield
1361 creation below, which is typically required when no position has been
1364 size = convert (bitsizetype, size);
1365 else if (packed == 1)
1367 size = rm_size (field_type);
1369 /* For a constant size larger than MAX_FIXED_MODE_SIZE, round up to
1371 if (TREE_CODE (size) == INTEGER_CST
1372 && compare_tree_int (size, MAX_FIXED_MODE_SIZE) > 0)
1373 size = round_up (size, BITS_PER_UNIT);
1376 /* If we may, according to ADDRESSABLE, make a bitfield if a size is
1377 specified for two reasons: first if the size differs from the natural
1378 size. Second, if the alignment is insufficient. There are a number of
1379 ways the latter can be true.
1381 We never make a bitfield if the type of the field has a nonconstant size,
1382 because no such entity requiring bitfield operations should reach here.
1384 We do *preventively* make a bitfield when there might be the need for it
1385 but we don't have all the necessary information to decide, as is the case
1386 of a field with no specified position in a packed record.
1388 We also don't look at STRICT_ALIGNMENT here, and rely on later processing
1389 in layout_decl or finish_record_type to clear the bit_field indication if
1390 it is in fact not needed. */
1391 if (addressable >= 0
1393 && TREE_CODE (size) == INTEGER_CST
1394 && TREE_CODE (TYPE_SIZE (field_type)) == INTEGER_CST
1395 && (!operand_equal_p (TYPE_SIZE (field_type), size, 0)
1396 || (pos && !value_factor_p (pos, TYPE_ALIGN (field_type)))
1398 || (TYPE_ALIGN (record_type) != 0
1399 && TYPE_ALIGN (record_type) < TYPE_ALIGN (field_type))))
1401 DECL_BIT_FIELD (field_decl) = 1;
1402 DECL_SIZE (field_decl) = size;
1403 if (!packed && !pos)
1404 DECL_ALIGN (field_decl)
1405 = (TYPE_ALIGN (record_type) != 0
1406 ? MIN (TYPE_ALIGN (record_type), TYPE_ALIGN (field_type))
1407 : TYPE_ALIGN (field_type));
1410 DECL_PACKED (field_decl) = pos ? DECL_BIT_FIELD (field_decl) : packed;
1411 DECL_ALIGN (field_decl)
1412 = MAX (DECL_ALIGN (field_decl),
1413 DECL_BIT_FIELD (field_decl) ? 1
1414 : packed && TYPE_MODE (field_type) != BLKmode ? BITS_PER_UNIT
1415 : TYPE_ALIGN (field_type));
1419 /* We need to pass in the alignment the DECL is known to have.
1420 This is the lowest-order bit set in POS, but no more than
1421 the alignment of the record, if one is specified. Note
1422 that an alignment of 0 is taken as infinite. */
1423 unsigned int known_align;
1425 if (host_integerp (pos, 1))
1426 known_align = tree_low_cst (pos, 1) & - tree_low_cst (pos, 1);
1428 known_align = BITS_PER_UNIT;
1430 if (TYPE_ALIGN (record_type)
1431 && (known_align == 0 || known_align > TYPE_ALIGN (record_type)))
1432 known_align = TYPE_ALIGN (record_type);
1434 layout_decl (field_decl, known_align);
1435 SET_DECL_OFFSET_ALIGN (field_decl,
1436 host_integerp (pos, 1) ? BIGGEST_ALIGNMENT
1438 pos_from_bit (&DECL_FIELD_OFFSET (field_decl),
1439 &DECL_FIELD_BIT_OFFSET (field_decl),
1440 DECL_OFFSET_ALIGN (field_decl), pos);
1442 DECL_HAS_REP_P (field_decl) = 1;
1445 /* If the field type is passed by reference, we will have pointers to the
1446 field, so it is addressable. */
1447 if (must_pass_by_ref (field_type) || default_pass_by_ref (field_type))
1450 /* ??? For now, we say that any field of aggregate type is addressable
1451 because the front end may take 'Reference of it. */
1452 if (AGGREGATE_TYPE_P (field_type))
1455 /* Mark the decl as nonaddressable if it is indicated so semantically,
1456 meaning we won't ever attempt to take the address of the field.
1458 It may also be "technically" nonaddressable, meaning that even if we
1459 attempt to take the field's address we will actually get the address of a
1460 copy. This is the case for true bitfields, but the DECL_BIT_FIELD value
1461 we have at this point is not accurate enough, so we don't account for
1462 this here and let finish_record_type decide. */
1463 DECL_NONADDRESSABLE_P (field_decl) = !addressable;
1468 /* Subroutine of previous function: return nonzero if EXP, ignoring any side
1469 effects, has the value of zero. */
1472 value_zerop (tree exp)
1474 if (TREE_CODE (exp) == COMPOUND_EXPR)
1475 return value_zerop (TREE_OPERAND (exp, 1));
1477 return integer_zerop (exp);
1480 /* Returns a PARM_DECL node. PARAM_NAME is the name of the parameter,
1481 PARAM_TYPE is its type. READONLY is true if the parameter is
1482 readonly (either an IN parameter or an address of a pass-by-ref
1486 create_param_decl (tree param_name, tree param_type, bool readonly)
1488 tree param_decl = build_decl (PARM_DECL, param_name, param_type);
1490 /* Honor targetm.calls.promote_prototypes(), as not doing so can
1491 lead to various ABI violations. */
1492 if (targetm.calls.promote_prototypes (param_type)
1493 && (TREE_CODE (param_type) == INTEGER_TYPE
1494 || TREE_CODE (param_type) == ENUMERAL_TYPE)
1495 && TYPE_PRECISION (param_type) < TYPE_PRECISION (integer_type_node))
1497 /* We have to be careful about biased types here. Make a subtype
1498 of integer_type_node with the proper biasing. */
1499 if (TREE_CODE (param_type) == INTEGER_TYPE
1500 && TYPE_BIASED_REPRESENTATION_P (param_type))
1503 = copy_type (build_range_type (integer_type_node,
1504 TYPE_MIN_VALUE (param_type),
1505 TYPE_MAX_VALUE (param_type)));
1507 TYPE_BIASED_REPRESENTATION_P (param_type) = 1;
1510 param_type = integer_type_node;
1513 DECL_ARG_TYPE (param_decl) = param_type;
1514 TREE_READONLY (param_decl) = readonly;
1518 /* Given a DECL and ATTR_LIST, process the listed attributes. */
1521 process_attributes (tree decl, struct attrib *attr_list)
1523 for (; attr_list; attr_list = attr_list->next)
1524 switch (attr_list->type)
1526 case ATTR_MACHINE_ATTRIBUTE:
1527 decl_attributes (&decl, tree_cons (attr_list->name, attr_list->args,
1529 ATTR_FLAG_TYPE_IN_PLACE);
1532 case ATTR_LINK_ALIAS:
1533 if (! DECL_EXTERNAL (decl))
1535 TREE_STATIC (decl) = 1;
1536 assemble_alias (decl, attr_list->name);
1540 case ATTR_WEAK_EXTERNAL:
1542 declare_weak (decl);
1544 post_error ("?weak declarations not supported on this target",
1545 attr_list->error_point);
1548 case ATTR_LINK_SECTION:
1549 if (targetm.have_named_sections)
1551 DECL_SECTION_NAME (decl)
1552 = build_string (IDENTIFIER_LENGTH (attr_list->name),
1553 IDENTIFIER_POINTER (attr_list->name));
1554 DECL_COMMON (decl) = 0;
1557 post_error ("?section attributes are not supported for this target",
1558 attr_list->error_point);
1561 case ATTR_LINK_CONSTRUCTOR:
1562 DECL_STATIC_CONSTRUCTOR (decl) = 1;
1563 TREE_USED (decl) = 1;
1566 case ATTR_LINK_DESTRUCTOR:
1567 DECL_STATIC_DESTRUCTOR (decl) = 1;
1568 TREE_USED (decl) = 1;
1573 /* Return true if VALUE is a known to be a multiple of FACTOR, which must be
1577 value_factor_p (tree value, HOST_WIDE_INT factor)
1579 if (host_integerp (value, 1))
1580 return tree_low_cst (value, 1) % factor == 0;
1582 if (TREE_CODE (value) == MULT_EXPR)
1583 return (value_factor_p (TREE_OPERAND (value, 0), factor)
1584 || value_factor_p (TREE_OPERAND (value, 1), factor));
1589 /* Given 2 consecutive field decls PREV_FIELD and CURR_FIELD, return true
1590 unless we can prove these 2 fields are laid out in such a way that no gap
1591 exist between the end of PREV_FIELD and the beginning of CURR_FIELD. OFFSET
1592 is the distance in bits between the end of PREV_FIELD and the starting
1593 position of CURR_FIELD. It is ignored if null. */
1596 potential_alignment_gap (tree prev_field, tree curr_field, tree offset)
1598 /* If this is the first field of the record, there cannot be any gap */
1602 /* If the previous field is a union type, then return False: The only
1603 time when such a field is not the last field of the record is when
1604 there are other components at fixed positions after it (meaning there
1605 was a rep clause for every field), in which case we don't want the
1606 alignment constraint to override them. */
1607 if (TREE_CODE (TREE_TYPE (prev_field)) == QUAL_UNION_TYPE)
1610 /* If the distance between the end of prev_field and the beginning of
1611 curr_field is constant, then there is a gap if the value of this
1612 constant is not null. */
1613 if (offset && host_integerp (offset, 1))
1614 return !integer_zerop (offset);
1616 /* If the size and position of the previous field are constant,
1617 then check the sum of this size and position. There will be a gap
1618 iff it is not multiple of the current field alignment. */
1619 if (host_integerp (DECL_SIZE (prev_field), 1)
1620 && host_integerp (bit_position (prev_field), 1))
1621 return ((tree_low_cst (bit_position (prev_field), 1)
1622 + tree_low_cst (DECL_SIZE (prev_field), 1))
1623 % DECL_ALIGN (curr_field) != 0);
1625 /* If both the position and size of the previous field are multiples
1626 of the current field alignment, there cannot be any gap. */
1627 if (value_factor_p (bit_position (prev_field), DECL_ALIGN (curr_field))
1628 && value_factor_p (DECL_SIZE (prev_field), DECL_ALIGN (curr_field)))
1631 /* Fallback, return that there may be a potential gap */
1635 /* Returns a LABEL_DECL node for LABEL_NAME. */
1638 create_label_decl (tree label_name)
1640 tree label_decl = build_decl (LABEL_DECL, label_name, void_type_node);
1642 DECL_CONTEXT (label_decl) = current_function_decl;
1643 DECL_MODE (label_decl) = VOIDmode;
1644 DECL_SOURCE_LOCATION (label_decl) = input_location;
1649 /* Returns a FUNCTION_DECL node. SUBPROG_NAME is the name of the subprogram,
1650 ASM_NAME is its assembler name, SUBPROG_TYPE is its type (a FUNCTION_TYPE
1651 node), PARAM_DECL_LIST is the list of the subprogram arguments (a list of
1652 PARM_DECL nodes chained through the TREE_CHAIN field).
1654 INLINE_FLAG, PUBLIC_FLAG, EXTERN_FLAG, and ATTR_LIST are used to set the
1655 appropriate fields in the FUNCTION_DECL. GNAT_NODE gives the location. */
1658 create_subprog_decl (tree subprog_name, tree asm_name,
1659 tree subprog_type, tree param_decl_list, bool inline_flag,
1660 bool public_flag, bool extern_flag,
1661 struct attrib *attr_list, Node_Id gnat_node)
1663 tree return_type = TREE_TYPE (subprog_type);
1664 tree subprog_decl = build_decl (FUNCTION_DECL, subprog_name, subprog_type);
1666 /* If this is a function nested inside an inlined external function, it
1667 means we aren't going to compile the outer function unless it is
1668 actually inlined, so do the same for us. */
1669 if (current_function_decl && DECL_INLINE (current_function_decl)
1670 && DECL_EXTERNAL (current_function_decl))
1673 DECL_EXTERNAL (subprog_decl) = extern_flag;
1674 TREE_PUBLIC (subprog_decl) = public_flag;
1675 TREE_STATIC (subprog_decl) = 1;
1676 TREE_READONLY (subprog_decl) = TYPE_READONLY (subprog_type);
1677 TREE_THIS_VOLATILE (subprog_decl) = TYPE_VOLATILE (subprog_type);
1678 TREE_SIDE_EFFECTS (subprog_decl) = TYPE_VOLATILE (subprog_type);
1679 DECL_ARGUMENTS (subprog_decl) = param_decl_list;
1680 DECL_RESULT (subprog_decl) = build_decl (RESULT_DECL, 0, return_type);
1681 DECL_ARTIFICIAL (DECL_RESULT (subprog_decl)) = 1;
1682 DECL_IGNORED_P (DECL_RESULT (subprog_decl)) = 1;
1685 DECL_DECLARED_INLINE_P (subprog_decl) = 1;
1688 SET_DECL_ASSEMBLER_NAME (subprog_decl, asm_name);
1690 process_attributes (subprog_decl, attr_list);
1692 /* Add this decl to the current binding level. */
1693 gnat_pushdecl (subprog_decl, gnat_node);
1695 /* Output the assembler code and/or RTL for the declaration. */
1696 rest_of_decl_compilation (subprog_decl, global_bindings_p (), 0);
1698 return subprog_decl;
1701 /* Set up the framework for generating code for SUBPROG_DECL, a subprogram
1702 body. This routine needs to be invoked before processing the declarations
1703 appearing in the subprogram. */
1706 begin_subprog_body (tree subprog_decl)
1710 current_function_decl = subprog_decl;
1711 announce_function (subprog_decl);
1713 /* Enter a new binding level and show that all the parameters belong to
1716 for (param_decl = DECL_ARGUMENTS (subprog_decl); param_decl;
1717 param_decl = TREE_CHAIN (param_decl))
1718 DECL_CONTEXT (param_decl) = subprog_decl;
1720 make_decl_rtl (subprog_decl);
1722 /* We handle pending sizes via the elaboration of types, so we don't need to
1723 save them. This causes them to be marked as part of the outer function
1724 and then discarded. */
1725 get_pending_sizes ();
1728 /* Finish the definition of the current subprogram and compile it all the way
1729 to assembler language output. BODY is the tree corresponding to
1733 end_subprog_body (tree body)
1735 tree fndecl = current_function_decl;
1737 /* Mark the BLOCK for this level as being for this function and pop the
1738 level. Since the vars in it are the parameters, clear them. */
1739 BLOCK_VARS (current_binding_level->block) = 0;
1740 BLOCK_SUPERCONTEXT (current_binding_level->block) = fndecl;
1741 DECL_INITIAL (fndecl) = current_binding_level->block;
1744 /* Deal with inline. If declared inline or we should default to inline,
1745 set the flag in the decl. */
1746 DECL_INLINE (fndecl)
1747 = DECL_DECLARED_INLINE_P (fndecl) || flag_inline_trees == 2;
1749 /* We handle pending sizes via the elaboration of types, so we don't
1750 need to save them. */
1751 get_pending_sizes ();
1753 /* Mark the RESULT_DECL as being in this subprogram. */
1754 DECL_CONTEXT (DECL_RESULT (fndecl)) = fndecl;
1756 DECL_SAVED_TREE (fndecl) = body;
1758 current_function_decl = DECL_CONTEXT (fndecl);
1761 /* If we're only annotating types, don't actually compile this function. */
1762 if (type_annotate_only)
1765 /* If we don't have .ctors/.dtors sections, and this is a static
1766 constructor or destructor, it must be recorded now. */
1767 if (DECL_STATIC_CONSTRUCTOR (fndecl) && !targetm.have_ctors_dtors)
1768 static_ctors = tree_cons (NULL_TREE, fndecl, static_ctors);
1770 if (DECL_STATIC_DESTRUCTOR (fndecl) && !targetm.have_ctors_dtors)
1771 static_dtors = tree_cons (NULL_TREE, fndecl, static_dtors);
1773 /* We do different things for nested and non-nested functions.
1774 ??? This should be in cgraph. */
1775 if (!DECL_CONTEXT (fndecl))
1777 gnat_gimplify_function (fndecl);
1778 cgraph_finalize_function (fndecl, false);
1781 /* Register this function with cgraph just far enough to get it
1782 added to our parent's nested function list. */
1783 (void) cgraph_node (fndecl);
1786 /* Convert FNDECL's code to GIMPLE and handle any nested functions. */
1789 gnat_gimplify_function (tree fndecl)
1791 struct cgraph_node *cgn;
1793 dump_function (TDI_original, fndecl);
1794 gimplify_function_tree (fndecl);
1795 dump_function (TDI_generic, fndecl);
1797 /* Convert all nested functions to GIMPLE now. We do things in this order
1798 so that items like VLA sizes are expanded properly in the context of the
1799 correct function. */
1800 cgn = cgraph_node (fndecl);
1801 for (cgn = cgn->nested; cgn; cgn = cgn->next_nested)
1802 gnat_gimplify_function (cgn->decl);
1805 /* Return a definition for a builtin function named NAME and whose data type
1806 is TYPE. TYPE should be a function type with argument types.
1807 FUNCTION_CODE tells later passes how to compile calls to this function.
1808 See tree.h for its possible values.
1810 If LIBRARY_NAME is nonzero, use that for DECL_ASSEMBLER_NAME,
1811 the name to be called if we can't opencode the function. If
1812 ATTRS is nonzero, use that for the function attribute list. */
1815 builtin_function (const char *name, tree type, int function_code,
1816 enum built_in_class class, const char *library_name,
1819 tree decl = build_decl (FUNCTION_DECL, get_identifier (name), type);
1821 DECL_EXTERNAL (decl) = 1;
1822 TREE_PUBLIC (decl) = 1;
1824 SET_DECL_ASSEMBLER_NAME (decl, get_identifier (library_name));
1826 gnat_pushdecl (decl, Empty);
1827 DECL_BUILT_IN_CLASS (decl) = class;
1828 DECL_FUNCTION_CODE (decl) = function_code;
1830 decl_attributes (&decl, attrs, ATTR_FLAG_BUILT_IN);
1834 /* Return an integer type with the number of bits of precision given by
1835 PRECISION. UNSIGNEDP is nonzero if the type is unsigned; otherwise
1836 it is a signed type. */
1839 gnat_type_for_size (unsigned precision, int unsignedp)
1844 if (precision <= 2 * MAX_BITS_PER_WORD
1845 && signed_and_unsigned_types[precision][unsignedp])
1846 return signed_and_unsigned_types[precision][unsignedp];
1849 t = make_unsigned_type (precision);
1851 t = make_signed_type (precision);
1853 if (precision <= 2 * MAX_BITS_PER_WORD)
1854 signed_and_unsigned_types[precision][unsignedp] = t;
1858 sprintf (type_name, "%sSIGNED_%d", unsignedp ? "UN" : "", precision);
1859 TYPE_NAME (t) = get_identifier (type_name);
1865 /* Likewise for floating-point types. */
1868 float_type_for_precision (int precision, enum machine_mode mode)
1873 if (float_types[(int) mode])
1874 return float_types[(int) mode];
1876 float_types[(int) mode] = t = make_node (REAL_TYPE);
1877 TYPE_PRECISION (t) = precision;
1880 gcc_assert (TYPE_MODE (t) == mode);
1883 sprintf (type_name, "FLOAT_%d", precision);
1884 TYPE_NAME (t) = get_identifier (type_name);
1890 /* Return a data type that has machine mode MODE. UNSIGNEDP selects
1891 an unsigned type; otherwise a signed type is returned. */
1894 gnat_type_for_mode (enum machine_mode mode, int unsignedp)
1896 if (mode == BLKmode)
1898 else if (mode == VOIDmode)
1899 return void_type_node;
1900 else if (COMPLEX_MODE_P (mode))
1902 else if (SCALAR_FLOAT_MODE_P (mode))
1903 return float_type_for_precision (GET_MODE_PRECISION (mode), mode);
1904 else if (SCALAR_INT_MODE_P (mode))
1905 return gnat_type_for_size (GET_MODE_BITSIZE (mode), unsignedp);
1910 /* Return the unsigned version of a TYPE_NODE, a scalar type. */
1913 gnat_unsigned_type (tree type_node)
1915 tree type = gnat_type_for_size (TYPE_PRECISION (type_node), 1);
1917 if (TREE_CODE (type_node) == INTEGER_TYPE && TYPE_MODULAR_P (type_node))
1919 type = copy_node (type);
1920 TREE_TYPE (type) = type_node;
1922 else if (TREE_TYPE (type_node)
1923 && TREE_CODE (TREE_TYPE (type_node)) == INTEGER_TYPE
1924 && TYPE_MODULAR_P (TREE_TYPE (type_node)))
1926 type = copy_node (type);
1927 TREE_TYPE (type) = TREE_TYPE (type_node);
1933 /* Return the signed version of a TYPE_NODE, a scalar type. */
1936 gnat_signed_type (tree type_node)
1938 tree type = gnat_type_for_size (TYPE_PRECISION (type_node), 0);
1940 if (TREE_CODE (type_node) == INTEGER_TYPE && TYPE_MODULAR_P (type_node))
1942 type = copy_node (type);
1943 TREE_TYPE (type) = type_node;
1945 else if (TREE_TYPE (type_node)
1946 && TREE_CODE (TREE_TYPE (type_node)) == INTEGER_TYPE
1947 && TYPE_MODULAR_P (TREE_TYPE (type_node)))
1949 type = copy_node (type);
1950 TREE_TYPE (type) = TREE_TYPE (type_node);
1956 /* Return a type the same as TYPE except unsigned or signed according to
1960 gnat_signed_or_unsigned_type (int unsignedp, tree type)
1962 if (!INTEGRAL_TYPE_P (type) || TYPE_UNSIGNED (type) == unsignedp)
1965 return gnat_type_for_size (TYPE_PRECISION (type), unsignedp);
1968 /* EXP is an expression for the size of an object. If this size contains
1969 discriminant references, replace them with the maximum (if MAX_P) or
1970 minimum (if !MAX_P) possible value of the discriminant. */
1973 max_size (tree exp, bool max_p)
1975 enum tree_code code = TREE_CODE (exp);
1976 tree type = TREE_TYPE (exp);
1978 switch (TREE_CODE_CLASS (code))
1980 case tcc_declaration:
1984 case tcc_exceptional:
1985 if (code == TREE_LIST)
1986 return tree_cons (TREE_PURPOSE (exp),
1987 max_size (TREE_VALUE (exp), max_p),
1989 ? max_size (TREE_CHAIN (exp), max_p) : NULL_TREE);
1993 /* If this contains a PLACEHOLDER_EXPR, it is the thing we want to
1994 modify. Otherwise, we treat it like a variable. */
1995 if (!CONTAINS_PLACEHOLDER_P (exp))
1998 type = TREE_TYPE (TREE_OPERAND (exp, 1));
2000 max_size (max_p ? TYPE_MAX_VALUE (type) : TYPE_MIN_VALUE (type), true);
2002 case tcc_comparison:
2003 return max_p ? size_one_node : size_zero_node;
2007 case tcc_expression:
2008 switch (TREE_CODE_LENGTH (code))
2011 if (code == NON_LVALUE_EXPR)
2012 return max_size (TREE_OPERAND (exp, 0), max_p);
2015 fold (build1 (code, type,
2016 max_size (TREE_OPERAND (exp, 0),
2017 code == NEGATE_EXPR ? !max_p : max_p)));
2020 if (code == COMPOUND_EXPR)
2021 return max_size (TREE_OPERAND (exp, 1), max_p);
2024 tree lhs = max_size (TREE_OPERAND (exp, 0), max_p);
2025 tree rhs = max_size (TREE_OPERAND (exp, 1),
2026 code == MINUS_EXPR ? !max_p : max_p);
2028 /* Special-case wanting the maximum value of a MIN_EXPR.
2029 In that case, if one side overflows, return the other.
2030 sizetype is signed, but we know sizes are non-negative.
2031 Likewise, handle a MINUS_EXPR or PLUS_EXPR with the LHS
2032 overflowing or the maximum possible value and the RHS
2036 && TREE_CODE (rhs) == INTEGER_CST
2037 && TREE_OVERFLOW (rhs))
2041 && TREE_CODE (lhs) == INTEGER_CST
2042 && TREE_OVERFLOW (lhs))
2044 else if ((code == MINUS_EXPR || code == PLUS_EXPR)
2045 && ((TREE_CODE (lhs) == INTEGER_CST
2046 && TREE_OVERFLOW (lhs))
2047 || operand_equal_p (lhs, TYPE_MAX_VALUE (type), 0))
2048 && !TREE_CONSTANT (rhs))
2051 return fold (build2 (code, type, lhs, rhs));
2055 if (code == SAVE_EXPR)
2057 else if (code == COND_EXPR)
2058 return fold (build2 (max_p ? MAX_EXPR : MIN_EXPR, type,
2059 max_size (TREE_OPERAND (exp, 1), max_p),
2060 max_size (TREE_OPERAND (exp, 2), max_p)));
2061 else if (code == CALL_EXPR && TREE_OPERAND (exp, 1))
2062 return build3 (CALL_EXPR, type, TREE_OPERAND (exp, 0),
2063 max_size (TREE_OPERAND (exp, 1), max_p), NULL);
2066 /* Other tree classes cannot happen. */
2074 /* Build a template of type TEMPLATE_TYPE from the array bounds of ARRAY_TYPE.
2075 EXPR is an expression that we can use to locate any PLACEHOLDER_EXPRs.
2076 Return a constructor for the template. */
2079 build_template (tree template_type, tree array_type, tree expr)
2081 tree template_elts = NULL_TREE;
2082 tree bound_list = NULL_TREE;
2085 if (TREE_CODE (array_type) == RECORD_TYPE
2086 && (TYPE_IS_PADDING_P (array_type)
2087 || TYPE_JUSTIFIED_MODULAR_P (array_type)))
2088 array_type = TREE_TYPE (TYPE_FIELDS (array_type));
2090 if (TREE_CODE (array_type) == ARRAY_TYPE
2091 || (TREE_CODE (array_type) == INTEGER_TYPE
2092 && TYPE_HAS_ACTUAL_BOUNDS_P (array_type)))
2093 bound_list = TYPE_ACTUAL_BOUNDS (array_type);
2095 /* First make the list for a CONSTRUCTOR for the template. Go down the
2096 field list of the template instead of the type chain because this
2097 array might be an Ada array of arrays and we can't tell where the
2098 nested arrays stop being the underlying object. */
2100 for (field = TYPE_FIELDS (template_type); field;
2102 ? (bound_list = TREE_CHAIN (bound_list))
2103 : (array_type = TREE_TYPE (array_type))),
2104 field = TREE_CHAIN (TREE_CHAIN (field)))
2106 tree bounds, min, max;
2108 /* If we have a bound list, get the bounds from there. Likewise
2109 for an ARRAY_TYPE. Otherwise, if expr is a PARM_DECL with
2110 DECL_BY_COMPONENT_PTR_P, use the bounds of the field in the template.
2111 This will give us a maximum range. */
2113 bounds = TREE_VALUE (bound_list);
2114 else if (TREE_CODE (array_type) == ARRAY_TYPE)
2115 bounds = TYPE_INDEX_TYPE (TYPE_DOMAIN (array_type));
2116 else if (expr && TREE_CODE (expr) == PARM_DECL
2117 && DECL_BY_COMPONENT_PTR_P (expr))
2118 bounds = TREE_TYPE (field);
2122 min = convert (TREE_TYPE (TREE_CHAIN (field)), TYPE_MIN_VALUE (bounds));
2123 max = convert (TREE_TYPE (field), TYPE_MAX_VALUE (bounds));
2125 /* If either MIN or MAX involve a PLACEHOLDER_EXPR, we must
2126 substitute it from OBJECT. */
2127 min = SUBSTITUTE_PLACEHOLDER_IN_EXPR (min, expr);
2128 max = SUBSTITUTE_PLACEHOLDER_IN_EXPR (max, expr);
2130 template_elts = tree_cons (TREE_CHAIN (field), max,
2131 tree_cons (field, min, template_elts));
2134 return gnat_build_constructor (template_type, nreverse (template_elts));
2137 /* Build a VMS descriptor from a Mechanism_Type, which must specify
2138 a descriptor type, and the GCC type of an object. Each FIELD_DECL
2139 in the type contains in its DECL_INITIAL the expression to use when
2140 a constructor is made for the type. GNAT_ENTITY is an entity used
2141 to print out an error message if the mechanism cannot be applied to
2142 an object of that type and also for the name. */
2145 build_vms_descriptor (tree type, Mechanism_Type mech, Entity_Id gnat_entity)
2147 tree record_type = make_node (RECORD_TYPE);
2148 tree field_list = 0;
2157 /* If TYPE is an unconstrained array, use the underlying array type. */
2158 if (TREE_CODE (type) == UNCONSTRAINED_ARRAY_TYPE)
2159 type = TREE_TYPE (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (type))));
2161 /* If this is an array, compute the number of dimensions in the array,
2162 get the index types, and point to the inner type. */
2163 if (TREE_CODE (type) != ARRAY_TYPE)
2166 for (ndim = 1, inner_type = type;
2167 TREE_CODE (TREE_TYPE (inner_type)) == ARRAY_TYPE
2168 && TYPE_MULTI_ARRAY_P (TREE_TYPE (inner_type));
2169 ndim++, inner_type = TREE_TYPE (inner_type))
2172 idx_arr = (tree *) alloca (ndim * sizeof (tree));
2174 if (mech != By_Descriptor_NCA
2175 && TREE_CODE (type) == ARRAY_TYPE && TYPE_CONVENTION_FORTRAN_P (type))
2176 for (i = ndim - 1, inner_type = type;
2178 i--, inner_type = TREE_TYPE (inner_type))
2179 idx_arr[i] = TYPE_DOMAIN (inner_type);
2181 for (i = 0, inner_type = type;
2183 i++, inner_type = TREE_TYPE (inner_type))
2184 idx_arr[i] = TYPE_DOMAIN (inner_type);
2186 /* Now get the DTYPE value. */
2187 switch (TREE_CODE (type))
2191 if (TYPE_VAX_FLOATING_POINT_P (type))
2192 switch (tree_low_cst (TYPE_DIGITS_VALUE (type), 1))
2205 switch (GET_MODE_BITSIZE (TYPE_MODE (type)))
2208 dtype = TYPE_UNSIGNED (type) ? 2 : 6;
2211 dtype = TYPE_UNSIGNED (type) ? 3 : 7;
2214 dtype = TYPE_UNSIGNED (type) ? 4 : 8;
2217 dtype = TYPE_UNSIGNED (type) ? 5 : 9;
2220 dtype = TYPE_UNSIGNED (type) ? 25 : 26;
2226 dtype = GET_MODE_BITSIZE (TYPE_MODE (type)) == 32 ? 52 : 53;
2230 if (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
2231 && TYPE_VAX_FLOATING_POINT_P (type))
2232 switch (tree_low_cst (TYPE_DIGITS_VALUE (type), 1))
2244 dtype = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (type))) == 32 ? 54: 55;
2255 /* Get the CLASS value. */
2258 case By_Descriptor_A:
2261 case By_Descriptor_NCA:
2264 case By_Descriptor_SB:
2271 /* Make the type for a descriptor for VMS. The first four fields
2272 are the same for all types. */
2275 = chainon (field_list,
2276 make_descriptor_field
2277 ("LENGTH", gnat_type_for_size (16, 1), record_type,
2278 size_in_bytes (mech == By_Descriptor_A ? inner_type : type)));
2280 field_list = chainon (field_list,
2281 make_descriptor_field ("DTYPE",
2282 gnat_type_for_size (8, 1),
2283 record_type, size_int (dtype)));
2284 field_list = chainon (field_list,
2285 make_descriptor_field ("CLASS",
2286 gnat_type_for_size (8, 1),
2287 record_type, size_int (class)));
2290 = chainon (field_list,
2291 make_descriptor_field
2293 build_pointer_type_for_mode (type, SImode, false), record_type,
2295 build_pointer_type_for_mode (type, SImode, false),
2296 build0 (PLACEHOLDER_EXPR, type))));
2301 case By_Descriptor_S:
2304 case By_Descriptor_SB:
2306 = chainon (field_list,
2307 make_descriptor_field
2308 ("SB_L1", gnat_type_for_size (32, 1), record_type,
2309 TREE_CODE (type) == ARRAY_TYPE
2310 ? TYPE_MIN_VALUE (TYPE_DOMAIN (type)) : size_zero_node));
2312 = chainon (field_list,
2313 make_descriptor_field
2314 ("SB_L2", gnat_type_for_size (32, 1), record_type,
2315 TREE_CODE (type) == ARRAY_TYPE
2316 ? TYPE_MAX_VALUE (TYPE_DOMAIN (type)) : size_zero_node));
2319 case By_Descriptor_A:
2320 case By_Descriptor_NCA:
2321 field_list = chainon (field_list,
2322 make_descriptor_field ("SCALE",
2323 gnat_type_for_size (8, 1),
2327 field_list = chainon (field_list,
2328 make_descriptor_field ("DIGITS",
2329 gnat_type_for_size (8, 1),
2334 = chainon (field_list,
2335 make_descriptor_field
2336 ("AFLAGS", gnat_type_for_size (8, 1), record_type,
2337 size_int (mech == By_Descriptor_NCA
2339 /* Set FL_COLUMN, FL_COEFF, and FL_BOUNDS. */
2340 : (TREE_CODE (type) == ARRAY_TYPE
2341 && TYPE_CONVENTION_FORTRAN_P (type)
2344 field_list = chainon (field_list,
2345 make_descriptor_field ("DIMCT",
2346 gnat_type_for_size (8, 1),
2350 field_list = chainon (field_list,
2351 make_descriptor_field ("ARSIZE",
2352 gnat_type_for_size (32, 1),
2354 size_in_bytes (type)));
2356 /* Now build a pointer to the 0,0,0... element. */
2357 tem = build0 (PLACEHOLDER_EXPR, type);
2358 for (i = 0, inner_type = type; i < ndim;
2359 i++, inner_type = TREE_TYPE (inner_type))
2360 tem = build4 (ARRAY_REF, TREE_TYPE (inner_type), tem,
2361 convert (TYPE_DOMAIN (inner_type), size_zero_node),
2362 NULL_TREE, NULL_TREE);
2365 = chainon (field_list,
2366 make_descriptor_field
2368 build_pointer_type_for_mode (inner_type, SImode, false),
2371 build_pointer_type_for_mode (inner_type, SImode,
2375 /* Next come the addressing coefficients. */
2377 for (i = 0; i < ndim; i++)
2381 = size_binop (MULT_EXPR, tem,
2382 size_binop (PLUS_EXPR,
2383 size_binop (MINUS_EXPR,
2384 TYPE_MAX_VALUE (idx_arr[i]),
2385 TYPE_MIN_VALUE (idx_arr[i])),
2388 fname[0] = (mech == By_Descriptor_NCA ? 'S' : 'M');
2389 fname[1] = '0' + i, fname[2] = 0;
2391 = chainon (field_list,
2392 make_descriptor_field (fname,
2393 gnat_type_for_size (32, 1),
2394 record_type, idx_length));
2396 if (mech == By_Descriptor_NCA)
2400 /* Finally here are the bounds. */
2401 for (i = 0; i < ndim; i++)
2405 fname[0] = 'L', fname[1] = '0' + i, fname[2] = 0;
2407 = chainon (field_list,
2408 make_descriptor_field
2409 (fname, gnat_type_for_size (32, 1), record_type,
2410 TYPE_MIN_VALUE (idx_arr[i])));
2414 = chainon (field_list,
2415 make_descriptor_field
2416 (fname, gnat_type_for_size (32, 1), record_type,
2417 TYPE_MAX_VALUE (idx_arr[i])));
2422 post_error ("unsupported descriptor type for &", gnat_entity);
2425 finish_record_type (record_type, field_list, false, true);
2426 create_type_decl (create_concat_name (gnat_entity, "DESC"), record_type,
2427 NULL, true, false, gnat_entity);
2432 /* Utility routine for above code to make a field. */
2435 make_descriptor_field (const char *name, tree type,
2436 tree rec_type, tree initial)
2439 = create_field_decl (get_identifier (name), type, rec_type, 0, 0, 0, 0);
2441 DECL_INITIAL (field) = initial;
2445 /* Build a type to be used to represent an aliased object whose nominal
2446 type is an unconstrained array. This consists of a RECORD_TYPE containing
2447 a field of TEMPLATE_TYPE and a field of OBJECT_TYPE, which is an
2448 ARRAY_TYPE. If ARRAY_TYPE is that of the unconstrained array, this
2449 is used to represent an arbitrary unconstrained object. Use NAME
2450 as the name of the record. */
2453 build_unc_object_type (tree template_type, tree object_type, tree name)
2455 tree type = make_node (RECORD_TYPE);
2456 tree template_field = create_field_decl (get_identifier ("BOUNDS"),
2457 template_type, type, 0, 0, 0, 1);
2458 tree array_field = create_field_decl (get_identifier ("ARRAY"), object_type,
2461 TYPE_NAME (type) = name;
2462 TYPE_CONTAINS_TEMPLATE_P (type) = 1;
2463 finish_record_type (type,
2464 chainon (chainon (NULL_TREE, template_field),
2471 /* Same, taking a thin or fat pointer type instead of a template type. */
2474 build_unc_object_type_from_ptr (tree thin_fat_ptr_type, tree object_type,
2479 gcc_assert (TYPE_FAT_OR_THIN_POINTER_P (thin_fat_ptr_type));
2482 = (TYPE_FAT_POINTER_P (thin_fat_ptr_type)
2483 ? TREE_TYPE (TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (thin_fat_ptr_type))))
2484 : TREE_TYPE (TYPE_FIELDS (TREE_TYPE (thin_fat_ptr_type))));
2485 return build_unc_object_type (template_type, object_type, name);
2488 /* Update anything previously pointing to OLD_TYPE to point to NEW_TYPE. In
2489 the normal case this is just two adjustments, but we have more to do
2490 if NEW is an UNCONSTRAINED_ARRAY_TYPE. */
2493 update_pointer_to (tree old_type, tree new_type)
2495 tree ptr = TYPE_POINTER_TO (old_type);
2496 tree ref = TYPE_REFERENCE_TO (old_type);
2500 /* If this is the main variant, process all the other variants first. */
2501 if (TYPE_MAIN_VARIANT (old_type) == old_type)
2502 for (type = TYPE_NEXT_VARIANT (old_type); type;
2503 type = TYPE_NEXT_VARIANT (type))
2504 update_pointer_to (type, new_type);
2506 /* If no pointer or reference, we are done. */
2510 /* Merge the old type qualifiers in the new type.
2512 Each old variant has qualifiers for specific reasons, and the new
2513 designated type as well. Each set of qualifiers represents useful
2514 information grabbed at some point, and merging the two simply unifies
2515 these inputs into the final type description.
2517 Consider for instance a volatile type frozen after an access to constant
2518 type designating it. After the designated type freeze, we get here with a
2519 volatile new_type and a dummy old_type with a readonly variant, created
2520 when the access type was processed. We shall make a volatile and readonly
2521 designated type, because that's what it really is.
2523 We might also get here for a non-dummy old_type variant with different
2524 qualifiers than the new_type ones, for instance in some cases of pointers
2525 to private record type elaboration (see the comments around the call to
2526 this routine from gnat_to_gnu_entity/E_Access_Type). We have to merge the
2527 qualifiers in thoses cases too, to avoid accidentally discarding the
2528 initial set, and will often end up with old_type == new_type then. */
2529 new_type = build_qualified_type (new_type,
2530 TYPE_QUALS (old_type)
2531 | TYPE_QUALS (new_type));
2533 /* If the new type and the old one are identical, there is nothing to
2535 if (old_type == new_type)
2538 /* Otherwise, first handle the simple case. */
2539 if (TREE_CODE (new_type) != UNCONSTRAINED_ARRAY_TYPE)
2541 TYPE_POINTER_TO (new_type) = ptr;
2542 TYPE_REFERENCE_TO (new_type) = ref;
2544 for (; ptr; ptr = TYPE_NEXT_PTR_TO (ptr))
2545 for (ptr1 = TYPE_MAIN_VARIANT (ptr); ptr1;
2546 ptr1 = TYPE_NEXT_VARIANT (ptr1))
2547 TREE_TYPE (ptr1) = new_type;
2549 for (; ref; ref = TYPE_NEXT_REF_TO (ref))
2550 for (ref1 = TYPE_MAIN_VARIANT (ref); ref1;
2551 ref1 = TYPE_NEXT_VARIANT (ref1))
2552 TREE_TYPE (ref1) = new_type;
2555 /* Now deal with the unconstrained array case. In this case the "pointer"
2556 is actually a RECORD_TYPE where the types of both fields are
2557 pointers to void. In that case, copy the field list from the
2558 old type to the new one and update the fields' context. */
2559 else if (TREE_CODE (ptr) != RECORD_TYPE || !TYPE_IS_FAT_POINTER_P (ptr))
2564 tree new_obj_rec = TYPE_OBJECT_RECORD_TYPE (new_type);
2569 SET_DECL_ORIGINAL_FIELD (TYPE_FIELDS (ptr),
2570 TYPE_FIELDS (TYPE_POINTER_TO (new_type)));
2571 SET_DECL_ORIGINAL_FIELD (TREE_CHAIN (TYPE_FIELDS (ptr)),
2572 TREE_CHAIN (TYPE_FIELDS
2573 (TYPE_POINTER_TO (new_type))));
2575 TYPE_FIELDS (ptr) = TYPE_FIELDS (TYPE_POINTER_TO (new_type));
2576 DECL_CONTEXT (TYPE_FIELDS (ptr)) = ptr;
2577 DECL_CONTEXT (TREE_CHAIN (TYPE_FIELDS (ptr))) = ptr;
2579 /* Rework the PLACEHOLDER_EXPR inside the reference to the
2582 ??? This is now the only use of gnat_substitute_in_type, which
2583 is now a very "heavy" routine to do this, so it should be replaced
2585 ptr_temp_type = TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (ptr)));
2586 new_ref = build3 (COMPONENT_REF, ptr_temp_type,
2587 build0 (PLACEHOLDER_EXPR, ptr),
2588 TREE_CHAIN (TYPE_FIELDS (ptr)), NULL_TREE);
2591 (TREE_TYPE (TREE_TYPE (TYPE_FIELDS (ptr))),
2592 gnat_substitute_in_type (TREE_TYPE (TREE_TYPE (TYPE_FIELDS (ptr))),
2593 TREE_CHAIN (TYPE_FIELDS (ptr)), new_ref));
2595 for (var = TYPE_MAIN_VARIANT (ptr); var; var = TYPE_NEXT_VARIANT (var))
2597 SET_TYPE_UNCONSTRAINED_ARRAY (var, new_type);
2599 /* This may seem a bit gross, in particular wrt DECL_CONTEXT, but
2600 actually is in keeping with what build_qualified_type does. */
2601 TYPE_FIELDS (var) = TYPE_FIELDS (ptr);
2604 TYPE_POINTER_TO (new_type) = TYPE_REFERENCE_TO (new_type)
2605 = TREE_TYPE (new_type) = ptr;
2607 /* Now handle updating the allocation record, what the thin pointer
2608 points to. Update all pointers from the old record into the new
2609 one, update the types of the fields, and recompute the size. */
2611 update_pointer_to (TYPE_OBJECT_RECORD_TYPE (old_type), new_obj_rec);
2613 TREE_TYPE (TYPE_FIELDS (new_obj_rec)) = TREE_TYPE (ptr_temp_type);
2614 TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (new_obj_rec)))
2615 = TREE_TYPE (TREE_TYPE (TYPE_FIELDS (ptr)));
2616 DECL_SIZE (TREE_CHAIN (TYPE_FIELDS (new_obj_rec)))
2617 = TYPE_SIZE (TREE_TYPE (TREE_TYPE (TYPE_FIELDS (ptr))));
2618 DECL_SIZE_UNIT (TREE_CHAIN (TYPE_FIELDS (new_obj_rec)))
2619 = TYPE_SIZE_UNIT (TREE_TYPE (TREE_TYPE (TYPE_FIELDS (ptr))));
2621 TYPE_SIZE (new_obj_rec)
2622 = size_binop (PLUS_EXPR,
2623 DECL_SIZE (TYPE_FIELDS (new_obj_rec)),
2624 DECL_SIZE (TREE_CHAIN (TYPE_FIELDS (new_obj_rec))));
2625 TYPE_SIZE_UNIT (new_obj_rec)
2626 = size_binop (PLUS_EXPR,
2627 DECL_SIZE_UNIT (TYPE_FIELDS (new_obj_rec)),
2628 DECL_SIZE_UNIT (TREE_CHAIN (TYPE_FIELDS (new_obj_rec))));
2629 rest_of_type_compilation (ptr, global_bindings_p ());
2633 /* Convert a pointer to a constrained array into a pointer to a fat
2634 pointer. This involves making or finding a template. */
2637 convert_to_fat_pointer (tree type, tree expr)
2639 tree template_type = TREE_TYPE (TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (type))));
2640 tree template, template_addr;
2641 tree etype = TREE_TYPE (expr);
2643 /* If EXPR is a constant of zero, we make a fat pointer that has a null
2644 pointer to the template and array. */
2645 if (integer_zerop (expr))
2647 gnat_build_constructor
2649 tree_cons (TYPE_FIELDS (type),
2650 convert (TREE_TYPE (TYPE_FIELDS (type)), expr),
2651 tree_cons (TREE_CHAIN (TYPE_FIELDS (type)),
2652 convert (build_pointer_type (template_type),
2656 /* If EXPR is a thin pointer, make the template and data from the record. */
2658 else if (TYPE_THIN_POINTER_P (etype))
2660 tree fields = TYPE_FIELDS (TREE_TYPE (etype));
2662 expr = save_expr (expr);
2663 if (TREE_CODE (expr) == ADDR_EXPR)
2664 expr = TREE_OPERAND (expr, 0);
2666 expr = build1 (INDIRECT_REF, TREE_TYPE (etype), expr);
2668 template = build_component_ref (expr, NULL_TREE, fields, false);
2669 expr = build_unary_op (ADDR_EXPR, NULL_TREE,
2670 build_component_ref (expr, NULL_TREE,
2671 TREE_CHAIN (fields), false));
2674 /* Otherwise, build the constructor for the template. */
2675 template = build_template (template_type, TREE_TYPE (etype), expr);
2677 template_addr = build_unary_op (ADDR_EXPR, NULL_TREE, template);
2679 /* The result is a CONSTRUCTOR for the fat pointer.
2681 If expr is an argument of a foreign convention subprogram, the type it
2682 points to is directly the component type. In this case, the expression
2683 type may not match the corresponding FIELD_DECL type at this point, so we
2684 call "convert" here to fix that up if necessary. This type consistency is
2685 required, for instance because it ensures that possible later folding of
2686 component_refs against this constructor always yields something of the
2687 same type as the initial reference.
2689 Note that the call to "build_template" above is still fine, because it
2690 will only refer to the provided template_type in this case. */
2692 gnat_build_constructor
2693 (type, tree_cons (TYPE_FIELDS (type),
2694 convert (TREE_TYPE (TYPE_FIELDS (type)), expr),
2695 tree_cons (TREE_CHAIN (TYPE_FIELDS (type)),
2696 template_addr, NULL_TREE)));
2699 /* Convert to a thin pointer type, TYPE. The only thing we know how to convert
2700 is something that is a fat pointer, so convert to it first if it EXPR
2701 is not already a fat pointer. */
2704 convert_to_thin_pointer (tree type, tree expr)
2706 if (!TYPE_FAT_POINTER_P (TREE_TYPE (expr)))
2708 = convert_to_fat_pointer
2709 (TREE_TYPE (TYPE_UNCONSTRAINED_ARRAY (TREE_TYPE (type))), expr);
2711 /* We get the pointer to the data and use a NOP_EXPR to make it the
2713 expr = build_component_ref (expr, NULL_TREE, TYPE_FIELDS (TREE_TYPE (expr)),
2715 expr = build1 (NOP_EXPR, type, expr);
2720 /* Create an expression whose value is that of EXPR,
2721 converted to type TYPE. The TREE_TYPE of the value
2722 is always TYPE. This function implements all reasonable
2723 conversions; callers should filter out those that are
2724 not permitted by the language being compiled. */
2727 convert (tree type, tree expr)
2729 enum tree_code code = TREE_CODE (type);
2730 tree etype = TREE_TYPE (expr);
2731 enum tree_code ecode = TREE_CODE (etype);
2733 /* If EXPR is already the right type, we are done. */
2737 /* If the input type has padding, remove it by doing a component reference
2738 to the field. If the output type has padding, make a constructor
2739 to build the record. If both input and output have padding and are
2740 of variable size, do this as an unchecked conversion. */
2741 else if (ecode == RECORD_TYPE && code == RECORD_TYPE
2742 && TYPE_IS_PADDING_P (type) && TYPE_IS_PADDING_P (etype)
2743 && (!TREE_CONSTANT (TYPE_SIZE (type))
2744 || !TREE_CONSTANT (TYPE_SIZE (etype))))
2746 else if (ecode == RECORD_TYPE && TYPE_IS_PADDING_P (etype))
2748 /* If we have just converted to this padded type, just get
2749 the inner expression. */
2750 if (TREE_CODE (expr) == CONSTRUCTOR
2751 && !VEC_empty (constructor_elt, CONSTRUCTOR_ELTS (expr))
2752 && VEC_index (constructor_elt, CONSTRUCTOR_ELTS (expr), 0)->index
2753 == TYPE_FIELDS (etype))
2754 return VEC_index (constructor_elt, CONSTRUCTOR_ELTS (expr), 0)->value;
2756 return convert (type,
2757 build_component_ref (expr, NULL_TREE,
2758 TYPE_FIELDS (etype), false));
2760 else if (code == RECORD_TYPE && TYPE_IS_PADDING_P (type))
2762 /* If we previously converted from another type and our type is
2763 of variable size, remove the conversion to avoid the need for
2764 variable-size temporaries. */
2765 if (TREE_CODE (expr) == VIEW_CONVERT_EXPR
2766 && !TREE_CONSTANT (TYPE_SIZE (type)))
2767 expr = TREE_OPERAND (expr, 0);
2769 /* If we are just removing the padding from expr, convert the original
2770 object if we have variable size. That will avoid the need
2771 for some variable-size temporaries. */
2772 if (TREE_CODE (expr) == COMPONENT_REF
2773 && TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == RECORD_TYPE
2774 && TYPE_IS_PADDING_P (TREE_TYPE (TREE_OPERAND (expr, 0)))
2775 && !TREE_CONSTANT (TYPE_SIZE (type)))
2776 return convert (type, TREE_OPERAND (expr, 0));
2778 /* If the result type is a padded type with a self-referentially-sized
2779 field and the expression type is a record, do this as an
2780 unchecked conversion. */
2781 else if (TREE_CODE (etype) == RECORD_TYPE
2782 && CONTAINS_PLACEHOLDER_P (DECL_SIZE (TYPE_FIELDS (type))))
2783 return unchecked_convert (type, expr, false);
2787 gnat_build_constructor (type,
2788 tree_cons (TYPE_FIELDS (type),
2790 (TYPE_FIELDS (type)),
2795 /* If the input is a biased type, adjust first. */
2796 if (ecode == INTEGER_TYPE && TYPE_BIASED_REPRESENTATION_P (etype))
2797 return convert (type, fold (build2 (PLUS_EXPR, TREE_TYPE (etype),
2798 fold_convert (TREE_TYPE (etype),
2800 TYPE_MIN_VALUE (etype))));
2802 /* If the input is a justified modular type, we need to extract the actual
2803 object before converting it to any other type with the exceptions of an
2804 unconstrained array or of a mere type variant. It is useful to avoid the
2805 extraction and conversion in the type variant case because it could end
2806 up replacing a VAR_DECL expr by a constructor and we might be about the
2807 take the address of the result. */
2808 if (ecode == RECORD_TYPE && TYPE_JUSTIFIED_MODULAR_P (etype)
2809 && code != UNCONSTRAINED_ARRAY_TYPE
2810 && TYPE_MAIN_VARIANT (type) != TYPE_MAIN_VARIANT (etype))
2811 return convert (type, build_component_ref (expr, NULL_TREE,
2812 TYPE_FIELDS (etype), false));
2814 /* If converting to a type that contains a template, convert to the data
2815 type and then build the template. */
2816 if (code == RECORD_TYPE && TYPE_CONTAINS_TEMPLATE_P (type))
2818 tree obj_type = TREE_TYPE (TREE_CHAIN (TYPE_FIELDS (type)));
2820 /* If the source already has a template, get a reference to the
2821 associated array only, as we are going to rebuild a template
2822 for the target type anyway. */
2823 expr = maybe_unconstrained_array (expr);
2826 gnat_build_constructor
2828 tree_cons (TYPE_FIELDS (type),
2829 build_template (TREE_TYPE (TYPE_FIELDS (type)),
2830 obj_type, NULL_TREE),
2831 tree_cons (TREE_CHAIN (TYPE_FIELDS (type)),
2832 convert (obj_type, expr), NULL_TREE)));
2835 /* There are some special cases of expressions that we process
2837 switch (TREE_CODE (expr))
2843 /* Just set its type here. For TRANSFORM_EXPR, we will do the actual
2844 conversion in gnat_expand_expr. NULL_EXPR does not represent
2845 and actual value, so no conversion is needed. */
2846 expr = copy_node (expr);
2847 TREE_TYPE (expr) = type;
2851 /* If we are converting a STRING_CST to another constrained array type,
2852 just make a new one in the proper type. */
2853 if (code == ecode && AGGREGATE_TYPE_P (etype)
2854 && !(TREE_CODE (TYPE_SIZE (etype)) == INTEGER_CST
2855 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST))
2857 expr = copy_node (expr);
2858 TREE_TYPE (expr) = type;
2863 case UNCONSTRAINED_ARRAY_REF:
2864 /* Convert this to the type of the inner array by getting the address of
2865 the array from the template. */
2866 expr = build_unary_op (INDIRECT_REF, NULL_TREE,
2867 build_component_ref (TREE_OPERAND (expr, 0),
2868 get_identifier ("P_ARRAY"),
2870 etype = TREE_TYPE (expr);
2871 ecode = TREE_CODE (etype);
2874 case VIEW_CONVERT_EXPR:
2876 /* GCC 4.x is very sensitive to type consistency overall, and view
2877 conversions thus are very frequent. Even though just "convert"ing
2878 the inner operand to the output type is fine in most cases, it
2879 might expose unexpected input/output type mismatches in special
2880 circumstances so we avoid such recursive calls when we can. */
2882 tree op0 = TREE_OPERAND (expr, 0);
2884 /* If we are converting back to the original type, we can just
2885 lift the input conversion. This is a common occurrence with
2886 switches back-and-forth amongst type variants. */
2887 if (type == TREE_TYPE (op0))
2890 /* Otherwise, if we're converting between two aggregate types, we
2891 might be allowed to substitute the VIEW_CONVERT target type in
2892 place or to just convert the inner expression. */
2893 if (AGGREGATE_TYPE_P (type) && AGGREGATE_TYPE_P (etype))
2895 /* If we are converting between type variants, we can just
2896 substitute the VIEW_CONVERT in place. */
2897 if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (etype))
2898 return build1 (VIEW_CONVERT_EXPR, type, op0);
2900 /* Otherwise, we may just bypass the input view conversion unless
2901 one of the types is a fat pointer, which is handled by
2902 specialized code below which relies on exact type matching. */
2903 else if (!TYPE_FAT_POINTER_P (type) && !TYPE_FAT_POINTER_P (etype))
2904 return convert (type, op0);
2910 /* If both types are record types, just convert the pointer and
2911 make a new INDIRECT_REF.
2913 ??? Disable this for now since it causes problems with the
2914 code in build_binary_op for MODIFY_EXPR which wants to
2915 strip off conversions. But that code really is a mess and
2916 we need to do this a much better way some time. */
2918 && (TREE_CODE (type) == RECORD_TYPE
2919 || TREE_CODE (type) == UNION_TYPE)
2920 && (TREE_CODE (etype) == RECORD_TYPE
2921 || TREE_CODE (etype) == UNION_TYPE)
2922 && !TYPE_FAT_POINTER_P (type) && !TYPE_FAT_POINTER_P (etype))
2923 return build_unary_op (INDIRECT_REF, NULL_TREE,
2924 convert (build_pointer_type (type),
2925 TREE_OPERAND (expr, 0)));
2932 /* Check for converting to a pointer to an unconstrained array. */
2933 if (TYPE_FAT_POINTER_P (type) && !TYPE_FAT_POINTER_P (etype))
2934 return convert_to_fat_pointer (type, expr);
2936 /* If we're converting between two aggregate types that have the same main
2937 variant, just make a VIEW_CONVER_EXPR. */
2938 else if (AGGREGATE_TYPE_P (type)
2939 && TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (etype))
2940 return build1 (VIEW_CONVERT_EXPR, type, expr);
2942 /* In all other cases of related types, make a NOP_EXPR. */
2943 else if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (etype)
2944 || (code == INTEGER_CST && ecode == INTEGER_CST
2945 && (type == TREE_TYPE (etype) || etype == TREE_TYPE (type))))
2946 return fold_convert (type, expr);
2951 return build1 (CONVERT_EXPR, type, expr);
2954 return fold_convert (type, gnat_truthvalue_conversion (expr));
2957 if (TYPE_HAS_ACTUAL_BOUNDS_P (type)
2958 && (ecode == ARRAY_TYPE || ecode == UNCONSTRAINED_ARRAY_TYPE
2959 || (ecode == RECORD_TYPE && TYPE_CONTAINS_TEMPLATE_P (etype))))
2960 return unchecked_convert (type, expr, false);
2961 else if (TYPE_BIASED_REPRESENTATION_P (type))
2962 return fold_convert (type,
2963 fold_build2 (MINUS_EXPR, TREE_TYPE (type),
2964 convert (TREE_TYPE (type), expr),
2965 TYPE_MIN_VALUE (type)));
2967 /* ... fall through ... */
2970 return fold (convert_to_integer (type, expr));
2973 case REFERENCE_TYPE:
2974 /* If converting between two pointers to records denoting
2975 both a template and type, adjust if needed to account
2976 for any differing offsets, since one might be negative. */
2977 if (TYPE_THIN_POINTER_P (etype) && TYPE_THIN_POINTER_P (type))
2980 = size_diffop (bit_position (TYPE_FIELDS (TREE_TYPE (etype))),
2981 bit_position (TYPE_FIELDS (TREE_TYPE (type))));
2982 tree byte_diff = size_binop (CEIL_DIV_EXPR, bit_diff,
2983 sbitsize_int (BITS_PER_UNIT));
2985 expr = build1 (NOP_EXPR, type, expr);
2986 TREE_CONSTANT (expr) = TREE_CONSTANT (TREE_OPERAND (expr, 0));
2987 if (integer_zerop (byte_diff))
2990 return build_binary_op (PLUS_EXPR, type, expr,
2991 fold (convert_to_pointer (type, byte_diff)));
2994 /* If converting to a thin pointer, handle specially. */
2995 if (TYPE_THIN_POINTER_P (type)
2996 && TYPE_UNCONSTRAINED_ARRAY (TREE_TYPE (type)))
2997 return convert_to_thin_pointer (type, expr);
2999 /* If converting fat pointer to normal pointer, get the pointer to the
3000 array and then convert it. */
3001 else if (TYPE_FAT_POINTER_P (etype))
3002 expr = build_component_ref (expr, get_identifier ("P_ARRAY"),
3005 return fold (convert_to_pointer (type, expr));
3008 return fold (convert_to_real (type, expr));
3011 if (TYPE_JUSTIFIED_MODULAR_P (type) && !AGGREGATE_TYPE_P (etype))
3013 gnat_build_constructor
3014 (type, tree_cons (TYPE_FIELDS (type),
3015 convert (TREE_TYPE (TYPE_FIELDS (type)), expr),
3018 /* ... fall through ... */
3021 /* In these cases, assume the front-end has validated the conversion.
3022 If the conversion is valid, it will be a bit-wise conversion, so
3023 it can be viewed as an unchecked conversion. */
3024 return unchecked_convert (type, expr, false);
3027 /* This is a either a conversion between a tagged type and some
3028 subtype, which we have to mark as a UNION_TYPE because of
3029 overlapping fields or a conversion of an Unchecked_Union. */
3030 return unchecked_convert (type, expr, false);
3032 case UNCONSTRAINED_ARRAY_TYPE:
3033 /* If EXPR is a constrained array, take its address, convert it to a
3034 fat pointer, and then dereference it. Likewise if EXPR is a
3035 record containing both a template and a constrained array.
3036 Note that a record representing a justified modular type
3037 always represents a packed constrained array. */
3038 if (ecode == ARRAY_TYPE
3039 || (ecode == INTEGER_TYPE && TYPE_HAS_ACTUAL_BOUNDS_P (etype))
3040 || (ecode == RECORD_TYPE && TYPE_CONTAINS_TEMPLATE_P (etype))
3041 || (ecode == RECORD_TYPE && TYPE_JUSTIFIED_MODULAR_P (etype)))
3044 (INDIRECT_REF, NULL_TREE,
3045 convert_to_fat_pointer (TREE_TYPE (type),
3046 build_unary_op (ADDR_EXPR,
3049 /* Do something very similar for converting one unconstrained
3050 array to another. */
3051 else if (ecode == UNCONSTRAINED_ARRAY_TYPE)
3053 build_unary_op (INDIRECT_REF, NULL_TREE,
3054 convert (TREE_TYPE (type),
3055 build_unary_op (ADDR_EXPR,
3061 return fold (convert_to_complex (type, expr));
3068 /* Remove all conversions that are done in EXP. This includes converting
3069 from a padded type or to a justified modular type. If TRUE_ADDRESS
3070 is true, always return the address of the containing object even if
3071 the address is not bit-aligned. */
3074 remove_conversions (tree exp, bool true_address)
3076 switch (TREE_CODE (exp))
3080 && TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE
3081 && TYPE_JUSTIFIED_MODULAR_P (TREE_TYPE (exp)))
3083 remove_conversions (VEC_index (constructor_elt,
3084 CONSTRUCTOR_ELTS (exp), 0)->value,
3089 if (TREE_CODE (TREE_TYPE (TREE_OPERAND (exp, 0))) == RECORD_TYPE
3090 && TYPE_IS_PADDING_P (TREE_TYPE (TREE_OPERAND (exp, 0))))
3091 return remove_conversions (TREE_OPERAND (exp, 0), true_address);
3094 case VIEW_CONVERT_EXPR: case NON_LVALUE_EXPR:
3095 case NOP_EXPR: case CONVERT_EXPR:
3096 return remove_conversions (TREE_OPERAND (exp, 0), true_address);
3105 /* If EXP's type is an UNCONSTRAINED_ARRAY_TYPE, return an expression that
3106 refers to the underlying array. If its type has TYPE_CONTAINS_TEMPLATE_P,
3107 likewise return an expression pointing to the underlying array. */
3110 maybe_unconstrained_array (tree exp)
3112 enum tree_code code = TREE_CODE (exp);
3115 switch (TREE_CODE (TREE_TYPE (exp)))
3117 case UNCONSTRAINED_ARRAY_TYPE:
3118 if (code == UNCONSTRAINED_ARRAY_REF)
3121 = build_unary_op (INDIRECT_REF, NULL_TREE,
3122 build_component_ref (TREE_OPERAND (exp, 0),
3123 get_identifier ("P_ARRAY"),
3125 TREE_READONLY (new) = TREE_STATIC (new) = TREE_READONLY (exp);
3129 else if (code == NULL_EXPR)
3130 return build1 (NULL_EXPR,
3131 TREE_TYPE (TREE_TYPE (TYPE_FIELDS
3132 (TREE_TYPE (TREE_TYPE (exp))))),
3133 TREE_OPERAND (exp, 0));
3136 /* If this is a padded type, convert to the unpadded type and see if
3137 it contains a template. */
3138 if (TYPE_IS_PADDING_P (TREE_TYPE (exp)))
3140 new = convert (TREE_TYPE (TYPE_FIELDS (TREE_TYPE (exp))), exp);
3141 if (TREE_CODE (TREE_TYPE (new)) == RECORD_TYPE
3142 && TYPE_CONTAINS_TEMPLATE_P (TREE_TYPE (new)))
3144 build_component_ref (new, NULL_TREE,
3145 TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (new))),
3148 else if (TYPE_CONTAINS_TEMPLATE_P (TREE_TYPE (exp)))
3150 build_component_ref (exp, NULL_TREE,
3151 TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (exp))), 0);
3161 /* Return an expression that does an unchecked conversion of EXPR to TYPE.
3162 If NOTRUNC_P is true, truncation operations should be suppressed. */
3165 unchecked_convert (tree type, tree expr, bool notrunc_p)
3167 tree etype = TREE_TYPE (expr);
3169 /* If the expression is already the right type, we are done. */
3173 /* If both types types are integral just do a normal conversion.
3174 Likewise for a conversion to an unconstrained array. */
3175 if ((((INTEGRAL_TYPE_P (type)
3176 && !(TREE_CODE (type) == INTEGER_TYPE
3177 && TYPE_VAX_FLOATING_POINT_P (type)))
3178 || (POINTER_TYPE_P (type) && ! TYPE_THIN_POINTER_P (type))
3179 || (TREE_CODE (type) == RECORD_TYPE
3180 && TYPE_JUSTIFIED_MODULAR_P (type)))
3181 && ((INTEGRAL_TYPE_P (etype)
3182 && !(TREE_CODE (etype) == INTEGER_TYPE
3183 && TYPE_VAX_FLOATING_POINT_P (etype)))
3184 || (POINTER_TYPE_P (etype) && !TYPE_THIN_POINTER_P (etype))
3185 || (TREE_CODE (etype) == RECORD_TYPE
3186 && TYPE_JUSTIFIED_MODULAR_P (etype))))
3187 || TREE_CODE (type) == UNCONSTRAINED_ARRAY_TYPE)
3191 if (TREE_CODE (etype) == INTEGER_TYPE
3192 && TYPE_BIASED_REPRESENTATION_P (etype))
3194 tree ntype = copy_type (etype);
3196 TYPE_BIASED_REPRESENTATION_P (ntype) = 0;
3197 TYPE_MAIN_VARIANT (ntype) = ntype;
3198 expr = build1 (NOP_EXPR, ntype, expr);
3201 if (TREE_CODE (type) == INTEGER_TYPE
3202 && TYPE_BIASED_REPRESENTATION_P (type))
3204 rtype = copy_type (type);
3205 TYPE_BIASED_REPRESENTATION_P (rtype) = 0;
3206 TYPE_MAIN_VARIANT (rtype) = rtype;
3209 expr = convert (rtype, expr);
3211 expr = build1 (NOP_EXPR, type, expr);
3214 /* If we are converting TO an integral type whose precision is not the
3215 same as its size, first unchecked convert to a record that contains
3216 an object of the output type. Then extract the field. */
3217 else if (INTEGRAL_TYPE_P (type) && TYPE_RM_SIZE (type)
3218 && 0 != compare_tree_int (TYPE_RM_SIZE (type),
3219 GET_MODE_BITSIZE (TYPE_MODE (type))))
3221 tree rec_type = make_node (RECORD_TYPE);
3222 tree field = create_field_decl (get_identifier ("OBJ"), type,
3223 rec_type, 1, 0, 0, 0);
3225 TYPE_FIELDS (rec_type) = field;
3226 layout_type (rec_type);
3228 expr = unchecked_convert (rec_type, expr, notrunc_p);
3229 expr = build_component_ref (expr, NULL_TREE, field, 0);
3232 /* Similarly for integral input type whose precision is not equal to its
3234 else if (INTEGRAL_TYPE_P (etype) && TYPE_RM_SIZE (etype)
3235 && 0 != compare_tree_int (TYPE_RM_SIZE (etype),
3236 GET_MODE_BITSIZE (TYPE_MODE (etype))))
3238 tree rec_type = make_node (RECORD_TYPE);
3240 = create_field_decl (get_identifier ("OBJ"), etype, rec_type,
3243 TYPE_FIELDS (rec_type) = field;
3244 layout_type (rec_type);
3246 expr = gnat_build_constructor (rec_type, build_tree_list (field, expr));
3247 expr = unchecked_convert (type, expr, notrunc_p);
3250 /* We have a special case when we are converting between two
3251 unconstrained array types. In that case, take the address,
3252 convert the fat pointer types, and dereference. */
3253 else if (TREE_CODE (etype) == UNCONSTRAINED_ARRAY_TYPE
3254 && TREE_CODE (type) == UNCONSTRAINED_ARRAY_TYPE)
3255 expr = build_unary_op (INDIRECT_REF, NULL_TREE,
3256 build1 (VIEW_CONVERT_EXPR, TREE_TYPE (type),
3257 build_unary_op (ADDR_EXPR, NULL_TREE,
3261 expr = maybe_unconstrained_array (expr);
3263 /* There's no point in doing two unchecked conversions in a row. */
3264 if (TREE_CODE (expr) == VIEW_CONVERT_EXPR)
3265 expr = TREE_OPERAND (expr, 0);
3267 etype = TREE_TYPE (expr);
3268 expr = build1 (VIEW_CONVERT_EXPR, type, expr);
3271 /* If the result is an integral type whose size is not equal to
3272 the size of the underlying machine type, sign- or zero-extend
3273 the result. We need not do this in the case where the input is
3274 an integral type of the same precision and signedness or if the output
3275 is a biased type or if both the input and output are unsigned. */
3277 && INTEGRAL_TYPE_P (type) && TYPE_RM_SIZE (type)
3278 && !(TREE_CODE (type) == INTEGER_TYPE
3279 && TYPE_BIASED_REPRESENTATION_P (type))
3280 && 0 != compare_tree_int (TYPE_RM_SIZE (type),
3281 GET_MODE_BITSIZE (TYPE_MODE (type)))
3282 && !(INTEGRAL_TYPE_P (etype)
3283 && TYPE_UNSIGNED (type) == TYPE_UNSIGNED (etype)
3284 && operand_equal_p (TYPE_RM_SIZE (type),
3285 (TYPE_RM_SIZE (etype) != 0
3286 ? TYPE_RM_SIZE (etype) : TYPE_SIZE (etype)),
3288 && !(TYPE_UNSIGNED (type) && TYPE_UNSIGNED (etype)))
3290 tree base_type = gnat_type_for_mode (TYPE_MODE (type),
3291 TYPE_UNSIGNED (type));
3293 = convert (base_type,
3294 size_binop (MINUS_EXPR,
3296 (GET_MODE_BITSIZE (TYPE_MODE (type))),
3297 TYPE_RM_SIZE (type)));
3300 build_binary_op (RSHIFT_EXPR, base_type,
3301 build_binary_op (LSHIFT_EXPR, base_type,
3302 convert (base_type, expr),
3307 /* An unchecked conversion should never raise Constraint_Error. The code
3308 below assumes that GCC's conversion routines overflow the same way that
3309 the underlying hardware does. This is probably true. In the rare case
3310 when it is false, we can rely on the fact that such conversions are
3311 erroneous anyway. */
3312 if (TREE_CODE (expr) == INTEGER_CST)
3313 TREE_OVERFLOW (expr) = TREE_CONSTANT_OVERFLOW (expr) = 0;
3315 /* If the sizes of the types differ and this is an VIEW_CONVERT_EXPR,
3316 show no longer constant. */
3317 if (TREE_CODE (expr) == VIEW_CONVERT_EXPR
3318 && !operand_equal_p (TYPE_SIZE_UNIT (type), TYPE_SIZE_UNIT (etype),
3320 TREE_CONSTANT (expr) = 0;
3325 /* Search the chain of currently reachable declarations for a builtin
3326 FUNCTION_DECL node corresponding to function NAME (an IDENTIFIER_NODE).
3327 Return the first node found, if any, or NULL_TREE otherwise. */
3330 builtin_decl_for (tree name __attribute__ ((unused)))
3332 /* ??? not clear yet how to implement this function in tree-ssa, so
3333 return NULL_TREE for now */
3337 #include "gt-ada-utils.h"
3338 #include "gtype-ada.h"