1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1996, 1998,
3 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
34 #include "langhooks.h"
36 /* Set to one when set_sizetype has been called. */
37 static int sizetype_set;
39 /* List of types created before set_sizetype has been called. We do not
40 make this a GGC root since we want these nodes to be reclaimed. */
41 static tree early_type_list;
43 /* Data type for the expressions representing sizes of data types.
44 It is the first integer type laid out. */
45 tree sizetype_tab[(int) TYPE_KIND_LAST];
47 /* If nonzero, this is an upper limit on alignment of structure fields.
48 The value is measured in bits. */
49 unsigned int maximum_field_alignment;
51 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
52 May be overridden by front-ends. */
53 unsigned int set_alignment = 0;
55 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
56 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
57 called only by a front end. */
58 static int reference_types_internal = 0;
60 static void finalize_record_size PARAMS ((record_layout_info));
61 static void finalize_type_size PARAMS ((tree));
62 static void place_union_field PARAMS ((record_layout_info, tree));
63 extern void debug_rli PARAMS ((record_layout_info));
65 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
67 static GTY(()) tree pending_sizes;
69 /* Nonzero means cannot safely call expand_expr now,
70 so put variable sizes onto `pending_sizes' instead. */
72 int immediate_size_expand;
74 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
78 internal_reference_types ()
80 reference_types_internal = 1;
83 /* Get a list of all the objects put on the pending sizes list. */
88 tree chain = pending_sizes;
91 /* Put each SAVE_EXPR into the current function. */
92 for (t = chain; t; t = TREE_CHAIN (t))
93 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
99 /* Return nonzero if EXPR is present on the pending sizes list. */
102 is_pending_size (expr)
107 for (t = pending_sizes; t; t = TREE_CHAIN (t))
108 if (TREE_VALUE (t) == expr)
113 /* Add EXPR to the pending sizes list. */
116 put_pending_size (expr)
119 /* Strip any simple arithmetic from EXPR to see if it has an underlying
121 while (TREE_CODE_CLASS (TREE_CODE (expr)) == '1'
122 || (TREE_CODE_CLASS (TREE_CODE (expr)) == '2'
123 && TREE_CONSTANT (TREE_OPERAND (expr, 1))))
124 expr = TREE_OPERAND (expr, 0);
126 if (TREE_CODE (expr) == SAVE_EXPR)
127 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
130 /* Put a chain of objects into the pending sizes list, which must be
134 put_pending_sizes (chain)
140 pending_sizes = chain;
143 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
144 to serve as the actual size-expression for a type or decl. */
150 /* If the language-processor is to take responsibility for variable-sized
151 items (e.g., languages which have elaboration procedures like Ada),
152 just return SIZE unchanged. Likewise for self-referential sizes and
154 if (TREE_CONSTANT (size)
155 || (*lang_hooks.decls.global_bindings_p) () < 0
156 || contains_placeholder_p (size))
159 size = save_expr (size);
161 /* If an array with a variable number of elements is declared, and
162 the elements require destruction, we will emit a cleanup for the
163 array. That cleanup is run both on normal exit from the block
164 and in the exception-handler for the block. Normally, when code
165 is used in both ordinary code and in an exception handler it is
166 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
167 not wish to do that here; the array-size is the same in both
169 if (TREE_CODE (size) == SAVE_EXPR)
170 SAVE_EXPR_PERSISTENT_P (size) = 1;
172 if ((*lang_hooks.decls.global_bindings_p) ())
174 if (TREE_CONSTANT (size))
175 error ("type size can't be explicitly evaluated");
177 error ("variable-size type declared outside of any function");
179 return size_one_node;
182 if (immediate_size_expand)
183 /* NULL_RTX is not defined; neither is the rtx type.
184 Also, we would like to pass const0_rtx here, but don't have it. */
185 expand_expr (size, expand_expr (integer_zero_node, NULL_RTX, VOIDmode, 0),
187 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
188 /* The front-end doesn't want us to keep a list of the expressions
189 that determine sizes for variable size objects. */
192 put_pending_size (size);
197 #ifndef MAX_FIXED_MODE_SIZE
198 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
201 /* Return the machine mode to use for a nonscalar of SIZE bits.
202 The mode must be in class CLASS, and have exactly that many bits.
203 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
207 mode_for_size (size, class, limit)
209 enum mode_class class;
212 enum machine_mode mode;
214 if (limit && size > MAX_FIXED_MODE_SIZE)
217 /* Get the first mode which has this size, in the specified class. */
218 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
219 mode = GET_MODE_WIDER_MODE (mode))
220 if (GET_MODE_BITSIZE (mode) == size)
226 /* Similar, except passed a tree node. */
229 mode_for_size_tree (size, class, limit)
231 enum mode_class class;
234 if (TREE_CODE (size) != INTEGER_CST
235 /* What we really want to say here is that the size can fit in a
236 host integer, but we know there's no way we'd find a mode for
237 this many bits, so there's no point in doing the precise test. */
238 || compare_tree_int (size, 1000) > 0)
241 return mode_for_size (TREE_INT_CST_LOW (size), class, limit);
244 /* Similar, but never return BLKmode; return the narrowest mode that
245 contains at least the requested number of bits. */
248 smallest_mode_for_size (size, class)
250 enum mode_class class;
252 enum machine_mode mode;
254 /* Get the first mode which has at least this size, in the
256 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
257 mode = GET_MODE_WIDER_MODE (mode))
258 if (GET_MODE_BITSIZE (mode) >= size)
264 /* Find an integer mode of the exact same size, or BLKmode on failure. */
267 int_mode_for_mode (mode)
268 enum machine_mode mode;
270 switch (GET_MODE_CLASS (mode))
273 case MODE_PARTIAL_INT:
276 case MODE_COMPLEX_INT:
277 case MODE_COMPLEX_FLOAT:
279 case MODE_VECTOR_INT:
280 case MODE_VECTOR_FLOAT:
281 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
288 /* ... fall through ... */
298 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
299 This can only be applied to objects of a sizetype. */
302 round_up (value, divisor)
306 tree arg = size_int_type (divisor, TREE_TYPE (value));
308 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
311 /* Likewise, but round down. */
314 round_down (value, divisor)
318 tree arg = size_int_type (divisor, TREE_TYPE (value));
320 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
323 /* Set the size, mode and alignment of a ..._DECL node.
324 TYPE_DECL does need this for C++.
325 Note that LABEL_DECL and CONST_DECL nodes do not need this,
326 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
327 Don't call layout_decl for them.
329 KNOWN_ALIGN is the amount of alignment we can assume this
330 decl has with no special effort. It is relevant only for FIELD_DECLs
331 and depends on the previous fields.
332 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
333 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
334 the record will be aligned to suit. */
337 layout_decl (decl, known_align)
339 unsigned int known_align;
341 tree type = TREE_TYPE (decl);
342 enum tree_code code = TREE_CODE (decl);
344 if (code == CONST_DECL)
346 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
347 && code != TYPE_DECL && code != FIELD_DECL)
350 if (type == error_mark_node)
351 type = void_type_node;
353 /* Usually the size and mode come from the data type without change,
354 however, the front-end may set the explicit width of the field, so its
355 size may not be the same as the size of its type. This happens with
356 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
357 also happens with other fields. For example, the C++ front-end creates
358 zero-sized fields corresponding to empty base classes, and depends on
359 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
360 size in bytes from the size in bits. If we have already set the mode,
361 don't set it again since we can be called twice for FIELD_DECLs. */
363 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
364 if (DECL_MODE (decl) == VOIDmode)
365 DECL_MODE (decl) = TYPE_MODE (type);
367 if (DECL_SIZE (decl) == 0)
369 DECL_SIZE (decl) = TYPE_SIZE (type);
370 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
373 DECL_SIZE_UNIT (decl)
374 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
377 /* Force alignment required for the data type.
378 But if the decl itself wants greater alignment, don't override that.
379 Likewise, if the decl is packed, don't override it. */
380 if (! (code == FIELD_DECL && DECL_BIT_FIELD (decl))
381 && (DECL_ALIGN (decl) == 0
382 || (! (code == FIELD_DECL && DECL_PACKED (decl))
383 && TYPE_ALIGN (type) > DECL_ALIGN (decl))))
385 DECL_ALIGN (decl) = TYPE_ALIGN (type);
386 DECL_USER_ALIGN (decl) = 0;
389 /* For fields, set the bit field type and update the alignment. */
390 if (code == FIELD_DECL)
392 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
393 if (maximum_field_alignment != 0)
394 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
396 /* If the field is of variable size, we can't misalign it since we
397 have no way to make a temporary to align the result. But this
398 isn't an issue if the decl is not addressable. Likewise if it
399 is of unknown size. */
400 else if (DECL_PACKED (decl)
401 && (DECL_NONADDRESSABLE_P (decl)
402 || DECL_SIZE_UNIT (decl) == 0
403 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
405 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
406 DECL_USER_ALIGN (decl) = 0;
410 /* See if we can use an ordinary integer mode for a bit-field.
411 Conditions are: a fixed size that is correct for another mode
412 and occupying a complete byte or bytes on proper boundary. */
413 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
414 && TYPE_SIZE (type) != 0
415 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
416 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
418 enum machine_mode xmode
419 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
421 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
423 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
425 DECL_MODE (decl) = xmode;
426 DECL_BIT_FIELD (decl) = 0;
430 /* Turn off DECL_BIT_FIELD if we won't need it set. */
431 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
432 && TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
433 && known_align >= TYPE_ALIGN (type)
434 && DECL_ALIGN (decl) >= TYPE_ALIGN (type)
435 && DECL_SIZE_UNIT (decl) != 0)
436 DECL_BIT_FIELD (decl) = 0;
438 /* Evaluate nonconstant size only once, either now or as soon as safe. */
439 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
440 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
441 if (DECL_SIZE_UNIT (decl) != 0
442 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
443 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
445 /* If requested, warn about definitions of large data objects. */
447 && (code == VAR_DECL || code == PARM_DECL)
448 && ! DECL_EXTERNAL (decl))
450 tree size = DECL_SIZE_UNIT (decl);
452 if (size != 0 && TREE_CODE (size) == INTEGER_CST
453 && compare_tree_int (size, larger_than_size) > 0)
455 unsigned int size_as_int = TREE_INT_CST_LOW (size);
457 if (compare_tree_int (size, size_as_int) == 0)
458 warning_with_decl (decl, "size of `%s' is %d bytes", size_as_int);
460 warning_with_decl (decl, "size of `%s' is larger than %d bytes",
466 /* Hook for a front-end function that can modify the record layout as needed
467 immediately before it is finalized. */
469 void (*lang_adjust_rli) PARAMS ((record_layout_info)) = 0;
472 set_lang_adjust_rli (f)
473 void (*f) PARAMS ((record_layout_info));
478 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
479 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
480 is to be passed to all other layout functions for this record. It is the
481 responsibility of the caller to call `free' for the storage returned.
482 Note that garbage collection is not permitted until we finish laying
486 start_record_layout (t)
489 record_layout_info rli
490 = (record_layout_info) xmalloc (sizeof (struct record_layout_info_s));
494 /* If the type has a minimum specified alignment (via an attribute
495 declaration, for example) use it -- otherwise, start with a
496 one-byte alignment. */
497 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
498 rli->unpacked_align = rli->unpadded_align = rli->record_align;
499 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
501 #ifdef STRUCTURE_SIZE_BOUNDARY
502 /* Packed structures don't need to have minimum size. */
503 if (! TYPE_PACKED (t))
504 rli->record_align = MAX (rli->record_align, STRUCTURE_SIZE_BOUNDARY);
507 rli->offset = size_zero_node;
508 rli->bitpos = bitsize_zero_node;
510 rli->pending_statics = 0;
511 rli->packed_maybe_necessary = 0;
516 /* These four routines perform computations that convert between
517 the offset/bitpos forms and byte and bit offsets. */
520 bit_from_pos (offset, bitpos)
523 return size_binop (PLUS_EXPR, bitpos,
524 size_binop (MULT_EXPR, convert (bitsizetype, offset),
529 byte_from_pos (offset, bitpos)
532 return size_binop (PLUS_EXPR, offset,
534 size_binop (TRUNC_DIV_EXPR, bitpos,
535 bitsize_unit_node)));
539 pos_from_byte (poffset, pbitpos, off_align, pos)
540 tree *poffset, *pbitpos;
541 unsigned int off_align;
545 = size_binop (MULT_EXPR,
547 size_binop (FLOOR_DIV_EXPR, pos,
548 bitsize_int (off_align
550 size_int (off_align / BITS_PER_UNIT));
551 *pbitpos = size_binop (MULT_EXPR,
552 size_binop (FLOOR_MOD_EXPR, pos,
553 bitsize_int (off_align / BITS_PER_UNIT)),
558 pos_from_bit (poffset, pbitpos, off_align, pos)
559 tree *poffset, *pbitpos;
560 unsigned int off_align;
563 *poffset = size_binop (MULT_EXPR,
565 size_binop (FLOOR_DIV_EXPR, pos,
566 bitsize_int (off_align))),
567 size_int (off_align / BITS_PER_UNIT));
568 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
571 /* Given a pointer to bit and byte offsets and an offset alignment,
572 normalize the offsets so they are within the alignment. */
575 normalize_offset (poffset, pbitpos, off_align)
576 tree *poffset, *pbitpos;
577 unsigned int off_align;
579 /* If the bit position is now larger than it should be, adjust it
581 if (compare_tree_int (*pbitpos, off_align) >= 0)
583 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
584 bitsize_int (off_align));
587 = size_binop (PLUS_EXPR, *poffset,
588 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
589 size_int (off_align / BITS_PER_UNIT)));
592 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
596 /* Print debugging information about the information in RLI. */
600 record_layout_info rli;
602 print_node_brief (stderr, "type", rli->t, 0);
603 print_node_brief (stderr, "\noffset", rli->offset, 0);
604 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
606 fprintf (stderr, "\naligns: rec = %u, unpack = %u, unpad = %u, off = %u\n",
607 rli->record_align, rli->unpacked_align, rli->unpadded_align,
609 if (rli->packed_maybe_necessary)
610 fprintf (stderr, "packed may be necessary\n");
612 if (rli->pending_statics)
614 fprintf (stderr, "pending statics:\n");
615 debug_tree (rli->pending_statics);
619 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
620 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
624 record_layout_info rli;
626 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
629 /* Returns the size in bytes allocated so far. */
632 rli_size_unit_so_far (rli)
633 record_layout_info rli;
635 return byte_from_pos (rli->offset, rli->bitpos);
638 /* Returns the size in bits allocated so far. */
641 rli_size_so_far (rli)
642 record_layout_info rli;
644 return bit_from_pos (rli->offset, rli->bitpos);
647 /* Called from place_field to handle unions. */
650 place_union_field (rli, field)
651 record_layout_info rli;
654 unsigned int desired_align;
656 layout_decl (field, 0);
658 DECL_FIELD_OFFSET (field) = size_zero_node;
659 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
660 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
662 desired_align = DECL_ALIGN (field);
664 #ifdef BIGGEST_FIELD_ALIGNMENT
665 /* Some targets (i.e. i386) limit union field alignment
666 to a lower boundary than alignment of variables unless
667 it was overridden by attribute aligned. */
668 if (! DECL_USER_ALIGN (field))
670 MIN (desired_align, (unsigned) BIGGEST_FIELD_ALIGNMENT);
673 #ifdef ADJUST_FIELD_ALIGN
674 if (! DECL_USER_ALIGN (field))
675 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
678 TYPE_USER_ALIGN (rli->t) |= DECL_USER_ALIGN (field);
680 /* Union must be at least as aligned as any field requires. */
681 rli->record_align = MAX (rli->record_align, desired_align);
682 rli->unpadded_align = MAX (rli->unpadded_align, desired_align);
684 #ifdef PCC_BITFIELD_TYPE_MATTERS
685 /* On the m88000, a bit field of declare type `int' forces the
686 entire union to have `int' alignment. */
687 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
689 unsigned int type_align = TYPE_ALIGN (TREE_TYPE (field));
691 #ifdef ADJUST_FIELD_ALIGN
692 if (! TYPE_USER_ALIGN (TREE_TYPE (field)))
693 type_align = ADJUST_FIELD_ALIGN (field, type_align);
695 rli->record_align = MAX (rli->record_align, type_align);
696 rli->unpadded_align = MAX (rli->unpadded_align, type_align);
697 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (TREE_TYPE (field));
701 /* We assume the union's size will be a multiple of a byte so we don't
702 bother with BITPOS. */
703 if (TREE_CODE (rli->t) == UNION_TYPE)
704 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
705 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
706 rli->offset = fold (build (COND_EXPR, sizetype,
707 DECL_QUALIFIER (field),
708 DECL_SIZE_UNIT (field), rli->offset));
711 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
712 is a FIELD_DECL to be added after those fields already present in
713 T. (FIELD is not actually added to the TYPE_FIELDS list here;
714 callers that desire that behavior must manually perform that step.) */
717 place_field (rli, field)
718 record_layout_info rli;
721 /* The alignment required for FIELD. */
722 unsigned int desired_align;
723 /* The alignment FIELD would have if we just dropped it into the
724 record as it presently stands. */
725 unsigned int known_align;
726 unsigned int actual_align;
727 unsigned int user_align;
728 /* The type of this field. */
729 tree type = TREE_TYPE (field);
731 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
734 /* If FIELD is static, then treat it like a separate variable, not
735 really like a structure field. If it is a FUNCTION_DECL, it's a
736 method. In both cases, all we do is lay out the decl, and we do
737 it *after* the record is laid out. */
738 if (TREE_CODE (field) == VAR_DECL)
740 rli->pending_statics = tree_cons (NULL_TREE, field,
741 rli->pending_statics);
745 /* Enumerators and enum types which are local to this class need not
746 be laid out. Likewise for initialized constant fields. */
747 else if (TREE_CODE (field) != FIELD_DECL)
750 /* Unions are laid out very differently than records, so split
751 that code off to another function. */
752 else if (TREE_CODE (rli->t) != RECORD_TYPE)
754 place_union_field (rli, field);
758 /* Work out the known alignment so far. Note that A & (-A) is the
759 value of the least-significant bit in A that is one. */
760 if (! integer_zerop (rli->bitpos))
761 known_align = (tree_low_cst (rli->bitpos, 1)
762 & - tree_low_cst (rli->bitpos, 1));
763 else if (integer_zerop (rli->offset))
764 known_align = BIGGEST_ALIGNMENT;
765 else if (host_integerp (rli->offset, 1))
766 known_align = (BITS_PER_UNIT
767 * (tree_low_cst (rli->offset, 1)
768 & - tree_low_cst (rli->offset, 1)));
770 known_align = rli->offset_align;
772 /* Lay out the field so we know what alignment it needs. For a
773 packed field, use the alignment as specified, disregarding what
774 the type would want. */
775 desired_align = DECL_ALIGN (field);
776 user_align = DECL_USER_ALIGN (field);
777 layout_decl (field, known_align);
778 if (! DECL_PACKED (field))
780 desired_align = DECL_ALIGN (field);
781 user_align = DECL_USER_ALIGN (field);
784 /* Some targets (i.e. i386, VMS) limit struct field alignment
785 to a lower boundary than alignment of variables unless
786 it was overridden by attribute aligned. */
787 #ifdef BIGGEST_FIELD_ALIGNMENT
790 = MIN (desired_align, (unsigned) BIGGEST_FIELD_ALIGNMENT);
793 #ifdef ADJUST_FIELD_ALIGN
795 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
798 /* Record must have at least as much alignment as any field.
799 Otherwise, the alignment of the field within the record is
801 if ((* targetm.ms_bitfield_layout_p) (rli->t)
802 && type != error_mark_node
803 && DECL_BIT_FIELD_TYPE (field)
804 && ! integer_zerop (TYPE_SIZE (type)))
806 /* Here, the alignment of the underlying type of a bitfield can
807 affect the alignment of a record; even a zero-sized field
808 can do this. The alignment should be to the alignment of
809 the type, except that for zero-size bitfields this only
810 applies if there was an immediately prior, nonzero-size
811 bitfield. (That's the way it is, experimentally.) */
812 if (! integer_zerop (DECL_SIZE (field))
813 ? ! DECL_PACKED (field)
815 && DECL_BIT_FIELD_TYPE (rli->prev_field)
816 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
818 unsigned int type_align = TYPE_ALIGN (type);
819 type_align = MAX (type_align, desired_align);
820 if (maximum_field_alignment != 0)
821 type_align = MIN (type_align, maximum_field_alignment);
822 rli->record_align = MAX (rli->record_align, type_align);
823 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
824 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
830 #ifdef PCC_BITFIELD_TYPE_MATTERS
831 if (PCC_BITFIELD_TYPE_MATTERS && type != error_mark_node
832 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
833 && DECL_BIT_FIELD_TYPE (field)
834 && ! integer_zerop (TYPE_SIZE (type)))
836 /* For these machines, a zero-length field does not
837 affect the alignment of the structure as a whole.
838 It does, however, affect the alignment of the next field
839 within the structure. */
840 if (! integer_zerop (DECL_SIZE (field)))
841 rli->record_align = MAX (rli->record_align, desired_align);
842 else if (! DECL_PACKED (field))
843 desired_align = TYPE_ALIGN (type);
845 /* A named bit field of declared type `int'
846 forces the entire structure to have `int' alignment. */
847 if (DECL_NAME (field) != 0)
849 unsigned int type_align = TYPE_ALIGN (type);
851 #ifdef ADJUST_FIELD_ALIGN
852 if (! TYPE_USER_ALIGN (type))
853 type_align = ADJUST_FIELD_ALIGN (field, type_align);
856 if (maximum_field_alignment != 0)
857 type_align = MIN (type_align, maximum_field_alignment);
858 else if (DECL_PACKED (field))
859 type_align = MIN (type_align, BITS_PER_UNIT);
861 rli->record_align = MAX (rli->record_align, type_align);
862 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
864 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
865 user_align |= TYPE_USER_ALIGN (type);
871 rli->record_align = MAX (rli->record_align, desired_align);
872 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
873 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
876 if (warn_packed && DECL_PACKED (field))
878 if (known_align > TYPE_ALIGN (type))
880 if (TYPE_ALIGN (type) > desired_align)
882 if (STRICT_ALIGNMENT)
883 warning_with_decl (field, "packed attribute causes inefficient alignment for `%s'");
885 warning_with_decl (field, "packed attribute is unnecessary for `%s'");
889 rli->packed_maybe_necessary = 1;
892 /* Does this field automatically have alignment it needs by virtue
893 of the fields that precede it and the record's own alignment? */
894 if (known_align < desired_align)
896 /* No, we need to skip space before this field.
897 Bump the cumulative size to multiple of field alignment. */
900 warning_with_decl (field, "padding struct to align `%s'");
902 /* If the alignment is still within offset_align, just align
904 if (desired_align < rli->offset_align)
905 rli->bitpos = round_up (rli->bitpos, desired_align);
908 /* First adjust OFFSET by the partial bits, then align. */
910 = size_binop (PLUS_EXPR, rli->offset,
912 size_binop (CEIL_DIV_EXPR, rli->bitpos,
913 bitsize_unit_node)));
914 rli->bitpos = bitsize_zero_node;
916 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
919 if (! TREE_CONSTANT (rli->offset))
920 rli->offset_align = desired_align;
924 /* Handle compatibility with PCC. Note that if the record has any
925 variable-sized fields, we need not worry about compatibility. */
926 #ifdef PCC_BITFIELD_TYPE_MATTERS
927 if (PCC_BITFIELD_TYPE_MATTERS
928 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
929 && TREE_CODE (field) == FIELD_DECL
930 && type != error_mark_node
931 && DECL_BIT_FIELD (field)
932 && ! DECL_PACKED (field)
933 && maximum_field_alignment == 0
934 && ! integer_zerop (DECL_SIZE (field))
935 && host_integerp (DECL_SIZE (field), 1)
936 && host_integerp (rli->offset, 1)
937 && host_integerp (TYPE_SIZE (type), 1))
939 unsigned int type_align = TYPE_ALIGN (type);
940 tree dsize = DECL_SIZE (field);
941 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
942 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
943 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
945 #ifdef ADJUST_FIELD_ALIGN
946 if (! TYPE_USER_ALIGN (type))
947 type_align = ADJUST_FIELD_ALIGN (field, type_align);
950 /* A bit field may not span more units of alignment of its type
951 than its type itself. Advance to next boundary if necessary. */
952 if ((((offset * BITS_PER_UNIT + bit_offset + field_size +
955 - (offset * BITS_PER_UNIT + bit_offset) / type_align)
956 > tree_low_cst (TYPE_SIZE (type), 1) / type_align)
957 rli->bitpos = round_up (rli->bitpos, type_align);
959 user_align |= TYPE_USER_ALIGN (type);
963 #ifdef BITFIELD_NBYTES_LIMITED
964 if (BITFIELD_NBYTES_LIMITED
965 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
966 && TREE_CODE (field) == FIELD_DECL
967 && type != error_mark_node
968 && DECL_BIT_FIELD_TYPE (field)
969 && ! DECL_PACKED (field)
970 && ! integer_zerop (DECL_SIZE (field))
971 && host_integerp (DECL_SIZE (field), 1)
972 && host_integerp (rli->offset, 1)
973 && host_integerp (TYPE_SIZE (type), 1))
975 unsigned int type_align = TYPE_ALIGN (type);
976 tree dsize = DECL_SIZE (field);
977 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
978 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
979 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
981 #ifdef ADJUST_FIELD_ALIGN
982 if (! TYPE_USER_ALIGN (type))
983 type_align = ADJUST_FIELD_ALIGN (field, type_align);
986 if (maximum_field_alignment != 0)
987 type_align = MIN (type_align, maximum_field_alignment);
988 /* ??? This test is opposite the test in the containing if
989 statement, so this code is unreachable currently. */
990 else if (DECL_PACKED (field))
991 type_align = MIN (type_align, BITS_PER_UNIT);
993 /* A bit field may not span the unit of alignment of its type.
994 Advance to next boundary if necessary. */
995 /* ??? This code should match the code above for the
996 PCC_BITFIELD_TYPE_MATTERS case. */
997 if ((offset * BITS_PER_UNIT + bit_offset) / type_align
998 != ((offset * BITS_PER_UNIT + bit_offset + field_size - 1)
1000 rli->bitpos = round_up (rli->bitpos, type_align);
1002 user_align |= TYPE_USER_ALIGN (type);
1006 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1008 When a bit field is inserted into a packed record, the whole
1009 size of the underlying type is used by one or more same-size
1010 adjacent bitfields. (That is, if its long:3, 32 bits is
1011 used in the record, and any additional adjacent long bitfields are
1012 packed into the same chunk of 32 bits. However, if the size
1013 changes, a new field of that size is allocated.) In an unpacked
1014 record, this is the same as using alignment, but not eqivalent
1017 Note: for compatability, we use the type size, not the type alignment
1018 to determine alignment, since that matches the documentation */
1020 if ((* targetm.ms_bitfield_layout_p) (rli->t)
1021 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1022 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1024 /* At this point, either the prior or current are bitfields,
1025 (possibly both), and we're dealing with MS packing. */
1026 tree prev_saved = rli->prev_field;
1028 /* Is the prior field a bitfield? If so, handle "runs" of same
1029 type size fields. */
1030 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1032 /* If both are bitfields, nonzero, and the same size, this is
1033 the middle of a run. Zero declared size fields are special
1034 and handled as "end of run". (Note: it's nonzero declared
1035 size, but equal type sizes!) (Since we know that both
1036 the current and previous fields are bitfields by the
1037 time we check it, DECL_SIZE must be present for both.) */
1038 if (DECL_BIT_FIELD_TYPE (field)
1039 && !integer_zerop (DECL_SIZE (field))
1040 && !integer_zerop (DECL_SIZE (rli->prev_field))
1041 && simple_cst_equal (TYPE_SIZE (type),
1042 TYPE_SIZE (TREE_TYPE (rli->prev_field))) )
1044 /* We're in the middle of a run of equal type size fields; make
1045 sure we realign if we run out of bits. (Not decl size,
1047 int bitsize = TREE_INT_CST_LOW (DECL_SIZE (field));
1048 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1050 if (rli->remaining_in_alignment < bitsize)
1052 /* out of bits; bump up to next 'word'. */
1053 rli->bitpos = size_binop (PLUS_EXPR,
1055 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1056 rli->prev_field = field;
1057 rli->remaining_in_alignment = TREE_INT_CST_LOW (type_size);
1059 rli->remaining_in_alignment -= bitsize;
1063 /* End of a run: if leaving a run of bitfields of the same type
1064 size, we have to "use up" the rest of the bits of the type
1067 Compute the new position as the sum of the size for the prior
1068 type and where we first started working on that type.
1069 Note: since the beginning of the field was aligned then
1070 of course the end will be too. No round needed. */
1072 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1074 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1075 rli->bitpos = size_binop (PLUS_EXPR,
1077 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1081 /* We "use up" size zero fields; the code below should behave
1082 as if the prior field was not a bitfield. */
1086 /* Cause a new bitfield to be captured, either this time (if
1087 currently a bitfield) or next time we see one. */
1088 if (!DECL_BIT_FIELD_TYPE(field)
1089 || integer_zerop (DECL_SIZE (field)))
1091 rli->prev_field = NULL;
1094 normalize_rli (rli);
1097 /* If we're starting a new run of same size type bitfields
1098 (or a run of non-bitfields), set up the "first of the run"
1101 That is, if the current field is not a bitfield, or if there
1102 was a prior bitfield the type sizes differ, or if there wasn't
1103 a prior bitfield the size of the current field is nonzero.
1105 Note: we must be sure to test ONLY the type size if there was
1106 a prior bitfield and ONLY for the current field being zero if
1109 if (!DECL_BIT_FIELD_TYPE (field)
1110 || ( prev_saved != NULL
1111 ? !simple_cst_equal (TYPE_SIZE (type),
1112 TYPE_SIZE (TREE_TYPE (prev_saved)))
1113 : !integer_zerop (DECL_SIZE (field)) ))
1115 unsigned int type_align = 8; /* Never below 8 for compatability */
1117 /* (When not a bitfield), we could be seeing a flex array (with
1118 no DECL_SIZE). Since we won't be using remaining_in_alignment
1119 until we see a bitfield (and come by here again) we just skip
1122 if (DECL_SIZE (field) != NULL)
1123 rli->remaining_in_alignment
1124 = TREE_INT_CST_LOW (TYPE_SIZE(TREE_TYPE(field)))
1125 - TREE_INT_CST_LOW (DECL_SIZE (field));
1127 /* Now align (conventionally) for the new type. */
1128 if (!DECL_PACKED(field))
1129 type_align = MAX(TYPE_ALIGN (type), type_align);
1132 && DECL_BIT_FIELD_TYPE (prev_saved)
1133 /* If the previous bit-field is zero-sized, we've already
1134 accounted for its alignment needs (or ignored it, if
1135 appropriate) while placing it. */
1136 && ! integer_zerop (DECL_SIZE (prev_saved)))
1137 type_align = MAX (type_align,
1138 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1140 if (maximum_field_alignment != 0)
1141 type_align = MIN (type_align, maximum_field_alignment);
1143 rli->bitpos = round_up (rli->bitpos, type_align);
1144 /* If we really aligned, don't allow subsequent bitfields
1146 rli->prev_field = NULL;
1150 /* Offset so far becomes the position of this field after normalizing. */
1151 normalize_rli (rli);
1152 DECL_FIELD_OFFSET (field) = rli->offset;
1153 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1154 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1156 TYPE_USER_ALIGN (rli->t) |= user_align;
1158 /* If this field ended up more aligned than we thought it would be (we
1159 approximate this by seeing if its position changed), lay out the field
1160 again; perhaps we can use an integral mode for it now. */
1161 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1162 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1163 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1164 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1165 actual_align = BIGGEST_ALIGNMENT;
1166 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1167 actual_align = (BITS_PER_UNIT
1168 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1169 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1171 actual_align = DECL_OFFSET_ALIGN (field);
1173 if (known_align != actual_align)
1174 layout_decl (field, actual_align);
1176 /* Only the MS bitfields use this. */
1177 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1178 rli->prev_field = field;
1180 /* Now add size of this field to the size of the record. If the size is
1181 not constant, treat the field as being a multiple of bytes and just
1182 adjust the offset, resetting the bit position. Otherwise, apportion the
1183 size amongst the bit position and offset. First handle the case of an
1184 unspecified size, which can happen when we have an invalid nested struct
1185 definition, such as struct j { struct j { int i; } }. The error message
1186 is printed in finish_struct. */
1187 if (DECL_SIZE (field) == 0)
1189 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1190 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1193 = size_binop (PLUS_EXPR, rli->offset,
1195 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1196 bitsize_unit_node)));
1198 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1199 rli->bitpos = bitsize_zero_node;
1200 rli->offset_align = MIN (rli->offset_align, DECL_ALIGN (field));
1204 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1205 normalize_rli (rli);
1209 /* Assuming that all the fields have been laid out, this function uses
1210 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1211 inidicated by RLI. */
1214 finalize_record_size (rli)
1215 record_layout_info rli;
1217 tree unpadded_size, unpadded_size_unit;
1219 /* Now we want just byte and bit offsets, so set the offset alignment
1220 to be a byte and then normalize. */
1221 rli->offset_align = BITS_PER_UNIT;
1222 normalize_rli (rli);
1224 /* Determine the desired alignment. */
1225 #ifdef ROUND_TYPE_ALIGN
1226 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1229 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1232 /* Compute the size so far. Be sure to allow for extra bits in the
1233 size in bytes. We have guaranteed above that it will be no more
1234 than a single byte. */
1235 unpadded_size = rli_size_so_far (rli);
1236 unpadded_size_unit = rli_size_unit_so_far (rli);
1237 if (! integer_zerop (rli->bitpos))
1239 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1241 /* Record the un-rounded size in the binfo node. But first we check
1242 the size of TYPE_BINFO to make sure that BINFO_SIZE is available. */
1243 if (TYPE_BINFO (rli->t) && TREE_VEC_LENGTH (TYPE_BINFO (rli->t)) > 6)
1245 TYPE_BINFO_SIZE (rli->t) = unpadded_size;
1246 TYPE_BINFO_SIZE_UNIT (rli->t) = unpadded_size_unit;
1249 /* Round the size up to be a multiple of the required alignment */
1250 #ifdef ROUND_TYPE_SIZE
1251 TYPE_SIZE (rli->t) = ROUND_TYPE_SIZE (rli->t, unpadded_size,
1252 TYPE_ALIGN (rli->t));
1253 TYPE_SIZE_UNIT (rli->t)
1254 = ROUND_TYPE_SIZE_UNIT (rli->t, unpadded_size_unit,
1255 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1257 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1258 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1259 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1262 if (warn_padded && TREE_CONSTANT (unpadded_size)
1263 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1264 warning ("padding struct size to alignment boundary");
1266 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1267 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1268 && TREE_CONSTANT (unpadded_size))
1272 #ifdef ROUND_TYPE_ALIGN
1274 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1276 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1279 #ifdef ROUND_TYPE_SIZE
1280 unpacked_size = ROUND_TYPE_SIZE (rli->t, TYPE_SIZE (rli->t),
1281 rli->unpacked_align);
1283 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1286 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1288 TYPE_PACKED (rli->t) = 0;
1290 if (TYPE_NAME (rli->t))
1294 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1295 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1297 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1299 if (STRICT_ALIGNMENT)
1300 warning ("packed attribute causes inefficient alignment for `%s'", name);
1302 warning ("packed attribute is unnecessary for `%s'", name);
1306 if (STRICT_ALIGNMENT)
1307 warning ("packed attribute causes inefficient alignment");
1309 warning ("packed attribute is unnecessary");
1315 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1318 compute_record_mode (type)
1322 enum machine_mode mode = VOIDmode;
1324 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1325 However, if possible, we use a mode that fits in a register
1326 instead, in order to allow for better optimization down the
1328 TYPE_MODE (type) = BLKmode;
1330 if (! host_integerp (TYPE_SIZE (type), 1))
1333 /* A record which has any BLKmode members must itself be
1334 BLKmode; it can't go in a register. Unless the member is
1335 BLKmode only because it isn't aligned. */
1336 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1338 unsigned HOST_WIDE_INT bitpos;
1340 if (TREE_CODE (field) != FIELD_DECL)
1343 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1344 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1345 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
1346 || ! host_integerp (bit_position (field), 1)
1347 || DECL_SIZE (field) == 0
1348 || ! host_integerp (DECL_SIZE (field), 1))
1351 bitpos = int_bit_position (field);
1353 /* Must be BLKmode if any field crosses a word boundary,
1354 since extract_bit_field can't handle that in registers. */
1355 if (bitpos / BITS_PER_WORD
1356 != ((tree_low_cst (DECL_SIZE (field), 1) + bitpos - 1)
1358 /* But there is no problem if the field is entire words. */
1359 && tree_low_cst (DECL_SIZE (field), 1) % BITS_PER_WORD != 0)
1362 /* If this field is the whole struct, remember its mode so
1363 that, say, we can put a double in a class into a DF
1364 register instead of forcing it to live in the stack. */
1365 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1366 mode = DECL_MODE (field);
1368 #ifdef MEMBER_TYPE_FORCES_BLK
1369 /* With some targets, eg. c4x, it is sub-optimal
1370 to access an aligned BLKmode structure as a scalar. */
1372 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1374 #endif /* MEMBER_TYPE_FORCES_BLK */
1377 /* If we only have one real field; use its mode. This only applies to
1378 RECORD_TYPE. This does not apply to unions. */
1379 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1380 TYPE_MODE (type) = mode;
1382 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1384 /* If structure's known alignment is less than what the scalar
1385 mode would need, and it matters, then stick with BLKmode. */
1386 if (TYPE_MODE (type) != BLKmode
1388 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1389 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1391 /* If this is the only reason this type is BLKmode, then
1392 don't force containing types to be BLKmode. */
1393 TYPE_NO_FORCE_BLK (type) = 1;
1394 TYPE_MODE (type) = BLKmode;
1398 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1402 finalize_type_size (type)
1405 /* Normally, use the alignment corresponding to the mode chosen.
1406 However, where strict alignment is not required, avoid
1407 over-aligning structures, since most compilers do not do this
1410 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1411 && (STRICT_ALIGNMENT
1412 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1413 && TREE_CODE (type) != QUAL_UNION_TYPE
1414 && TREE_CODE (type) != ARRAY_TYPE)))
1416 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1417 TYPE_USER_ALIGN (type) = 0;
1420 /* Do machine-dependent extra alignment. */
1421 #ifdef ROUND_TYPE_ALIGN
1423 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1426 /* If we failed to find a simple way to calculate the unit size
1427 of the type, find it by division. */
1428 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1429 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1430 result will fit in sizetype. We will get more efficient code using
1431 sizetype, so we force a conversion. */
1432 TYPE_SIZE_UNIT (type)
1433 = convert (sizetype,
1434 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1435 bitsize_unit_node));
1437 if (TYPE_SIZE (type) != 0)
1439 #ifdef ROUND_TYPE_SIZE
1441 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1442 TYPE_SIZE_UNIT (type)
1443 = ROUND_TYPE_SIZE_UNIT (type, TYPE_SIZE_UNIT (type),
1444 TYPE_ALIGN (type) / BITS_PER_UNIT);
1446 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1447 TYPE_SIZE_UNIT (type)
1448 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1452 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1453 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1454 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1455 if (TYPE_SIZE_UNIT (type) != 0
1456 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1457 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1459 /* Also layout any other variants of the type. */
1460 if (TYPE_NEXT_VARIANT (type)
1461 || type != TYPE_MAIN_VARIANT (type))
1464 /* Record layout info of this variant. */
1465 tree size = TYPE_SIZE (type);
1466 tree size_unit = TYPE_SIZE_UNIT (type);
1467 unsigned int align = TYPE_ALIGN (type);
1468 unsigned int user_align = TYPE_USER_ALIGN (type);
1469 enum machine_mode mode = TYPE_MODE (type);
1471 /* Copy it into all variants. */
1472 for (variant = TYPE_MAIN_VARIANT (type);
1474 variant = TYPE_NEXT_VARIANT (variant))
1476 TYPE_SIZE (variant) = size;
1477 TYPE_SIZE_UNIT (variant) = size_unit;
1478 TYPE_ALIGN (variant) = align;
1479 TYPE_USER_ALIGN (variant) = user_align;
1480 TYPE_MODE (variant) = mode;
1485 /* Do all of the work required to layout the type indicated by RLI,
1486 once the fields have been laid out. This function will call `free'
1490 finish_record_layout (rli)
1491 record_layout_info rli;
1493 /* Compute the final size. */
1494 finalize_record_size (rli);
1496 /* Compute the TYPE_MODE for the record. */
1497 compute_record_mode (rli->t);
1499 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1500 finalize_type_size (rli->t);
1502 /* Lay out any static members. This is done now because their type
1503 may use the record's type. */
1504 while (rli->pending_statics)
1506 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1507 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1514 /* Calculate the mode, size, and alignment for TYPE.
1515 For an array type, calculate the element separation as well.
1516 Record TYPE on the chain of permanent or temporary types
1517 so that dbxout will find out about it.
1519 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1520 layout_type does nothing on such a type.
1522 If the type is incomplete, its TYPE_SIZE remains zero. */
1531 /* Do nothing if type has been laid out before. */
1532 if (TYPE_SIZE (type))
1535 switch (TREE_CODE (type))
1538 /* This kind of type is the responsibility
1539 of the language-specific code. */
1542 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1543 if (TYPE_PRECISION (type) == 0)
1544 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1546 /* ... fall through ... */
1551 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1552 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1553 TREE_UNSIGNED (type) = 1;
1555 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1557 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1558 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1562 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1563 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1564 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1568 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1570 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1571 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1572 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1574 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1575 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1582 subtype = TREE_TYPE (type);
1583 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1584 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1585 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1590 /* This is an incomplete type and so doesn't have a size. */
1591 TYPE_ALIGN (type) = 1;
1592 TYPE_USER_ALIGN (type) = 0;
1593 TYPE_MODE (type) = VOIDmode;
1597 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1598 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1599 /* A pointer might be MODE_PARTIAL_INT,
1600 but ptrdiff_t must be integral. */
1601 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1606 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1607 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1608 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1612 case REFERENCE_TYPE:
1614 int nbits = ((TREE_CODE (type) == REFERENCE_TYPE
1615 && reference_types_internal)
1616 ? GET_MODE_BITSIZE (Pmode) : POINTER_SIZE);
1618 TYPE_MODE (type) = nbits == POINTER_SIZE ? ptr_mode : Pmode;
1619 TYPE_SIZE (type) = bitsize_int (nbits);
1620 TYPE_SIZE_UNIT (type) = size_int (nbits / BITS_PER_UNIT);
1621 TREE_UNSIGNED (type) = 1;
1622 TYPE_PRECISION (type) = nbits;
1628 tree index = TYPE_DOMAIN (type);
1629 tree element = TREE_TYPE (type);
1631 build_pointer_type (element);
1633 /* We need to know both bounds in order to compute the size. */
1634 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1635 && TYPE_SIZE (element))
1637 tree ub = TYPE_MAX_VALUE (index);
1638 tree lb = TYPE_MIN_VALUE (index);
1642 /* The initial subtraction should happen in the original type so
1643 that (possible) negative values are handled appropriately. */
1644 length = size_binop (PLUS_EXPR, size_one_node,
1646 fold (build (MINUS_EXPR,
1650 /* Special handling for arrays of bits (for Chill). */
1651 element_size = TYPE_SIZE (element);
1652 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1653 && (integer_zerop (TYPE_MAX_VALUE (element))
1654 || integer_onep (TYPE_MAX_VALUE (element)))
1655 && host_integerp (TYPE_MIN_VALUE (element), 1))
1657 HOST_WIDE_INT maxvalue
1658 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1659 HOST_WIDE_INT minvalue
1660 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1662 if (maxvalue - minvalue == 1
1663 && (maxvalue == 1 || maxvalue == 0))
1664 element_size = integer_one_node;
1667 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1668 convert (bitsizetype, length));
1670 /* If we know the size of the element, calculate the total
1671 size directly, rather than do some division thing below.
1672 This optimization helps Fortran assumed-size arrays
1673 (where the size of the array is determined at runtime)
1675 Note that we can't do this in the case where the size of
1676 the elements is one bit since TYPE_SIZE_UNIT cannot be
1677 set correctly in that case. */
1678 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1679 TYPE_SIZE_UNIT (type)
1680 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1683 /* Now round the alignment and size,
1684 using machine-dependent criteria if any. */
1686 #ifdef ROUND_TYPE_ALIGN
1688 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1690 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1692 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1694 #ifdef ROUND_TYPE_SIZE
1695 if (TYPE_SIZE (type) != 0)
1698 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1700 /* If the rounding changed the size of the type, remove any
1701 pre-calculated TYPE_SIZE_UNIT. */
1702 if (simple_cst_equal (TYPE_SIZE (type), tmp) != 1)
1703 TYPE_SIZE_UNIT (type) = NULL;
1705 TYPE_SIZE (type) = tmp;
1709 TYPE_MODE (type) = BLKmode;
1710 if (TYPE_SIZE (type) != 0
1711 #ifdef MEMBER_TYPE_FORCES_BLK
1712 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1714 /* BLKmode elements force BLKmode aggregate;
1715 else extract/store fields may lose. */
1716 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1717 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1719 /* One-element arrays get the component type's mode. */
1720 if (simple_cst_equal (TYPE_SIZE (type),
1721 TYPE_SIZE (TREE_TYPE (type))))
1722 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1725 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1727 if (TYPE_MODE (type) != BLKmode
1728 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1729 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1730 && TYPE_MODE (type) != BLKmode)
1732 TYPE_NO_FORCE_BLK (type) = 1;
1733 TYPE_MODE (type) = BLKmode;
1741 case QUAL_UNION_TYPE:
1744 record_layout_info rli;
1746 /* Initialize the layout information. */
1747 rli = start_record_layout (type);
1749 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1750 in the reverse order in building the COND_EXPR that denotes
1751 its size. We reverse them again later. */
1752 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1753 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1755 /* Place all the fields. */
1756 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1757 place_field (rli, field);
1759 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1760 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1762 if (lang_adjust_rli)
1763 (*lang_adjust_rli) (rli);
1765 /* Finish laying out the record. */
1766 finish_record_layout (rli);
1770 case SET_TYPE: /* Used by Chill and Pascal. */
1771 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1772 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1776 #ifndef SET_WORD_SIZE
1777 #define SET_WORD_SIZE BITS_PER_WORD
1779 unsigned int alignment
1780 = set_alignment ? set_alignment : SET_WORD_SIZE;
1782 = (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
1783 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1);
1785 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1787 if (rounded_size > (int) alignment)
1788 TYPE_MODE (type) = BLKmode;
1790 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1792 TYPE_SIZE (type) = bitsize_int (rounded_size);
1793 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1794 TYPE_ALIGN (type) = alignment;
1795 TYPE_USER_ALIGN (type) = 0;
1796 TYPE_PRECISION (type) = size_in_bits;
1801 /* The size may vary in different languages, so the language front end
1802 should fill in the size. */
1803 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1804 TYPE_USER_ALIGN (type) = 0;
1805 TYPE_MODE (type) = BLKmode;
1812 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1813 records and unions, finish_record_layout already called this
1815 if (TREE_CODE (type) != RECORD_TYPE
1816 && TREE_CODE (type) != UNION_TYPE
1817 && TREE_CODE (type) != QUAL_UNION_TYPE)
1818 finalize_type_size (type);
1820 /* If this type is created before sizetype has been permanently set,
1821 record it so set_sizetype can fix it up. */
1823 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1825 /* If an alias set has been set for this aggregate when it was incomplete,
1826 force it into alias set 0.
1827 This is too conservative, but we cannot call record_component_aliases
1828 here because some frontends still change the aggregates after
1830 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1831 TYPE_ALIAS_SET (type) = 0;
1834 /* Create and return a type for signed integers of PRECISION bits. */
1837 make_signed_type (precision)
1840 tree type = make_node (INTEGER_TYPE);
1842 TYPE_PRECISION (type) = precision;
1844 fixup_signed_type (type);
1848 /* Create and return a type for unsigned integers of PRECISION bits. */
1851 make_unsigned_type (precision)
1854 tree type = make_node (INTEGER_TYPE);
1856 TYPE_PRECISION (type) = precision;
1858 fixup_unsigned_type (type);
1862 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1863 value to enable integer types to be created. */
1866 initialize_sizetypes ()
1868 tree t = make_node (INTEGER_TYPE);
1870 /* Set this so we do something reasonable for the build_int_2 calls
1872 integer_type_node = t;
1874 TYPE_MODE (t) = SImode;
1875 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1876 TYPE_USER_ALIGN (t) = 0;
1877 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1878 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1879 TREE_UNSIGNED (t) = 1;
1880 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1881 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1882 TYPE_IS_SIZETYPE (t) = 1;
1884 /* 1000 avoids problems with possible overflow and is certainly
1885 larger than any size value we'd want to be storing. */
1886 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1888 /* These two must be different nodes because of the caching done in
1891 bitsizetype = copy_node (t);
1892 integer_type_node = 0;
1895 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1896 Also update the type of any standard type's sizes made so far. */
1902 int oprecision = TYPE_PRECISION (type);
1903 /* The *bitsizetype types use a precision that avoids overflows when
1904 calculating signed sizes / offsets in bits. However, when
1905 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1907 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1908 2 * HOST_BITS_PER_WIDE_INT);
1915 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1916 sizetype = copy_node (type);
1917 TYPE_DOMAIN (sizetype) = type;
1918 TYPE_IS_SIZETYPE (sizetype) = 1;
1919 bitsizetype = make_node (INTEGER_TYPE);
1920 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1921 TYPE_PRECISION (bitsizetype) = precision;
1922 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1924 if (TREE_UNSIGNED (type))
1925 fixup_unsigned_type (bitsizetype);
1927 fixup_signed_type (bitsizetype);
1929 layout_type (bitsizetype);
1931 if (TREE_UNSIGNED (type))
1933 usizetype = sizetype;
1934 ubitsizetype = bitsizetype;
1935 ssizetype = copy_node (make_signed_type (oprecision));
1936 sbitsizetype = copy_node (make_signed_type (precision));
1940 ssizetype = sizetype;
1941 sbitsizetype = bitsizetype;
1942 usizetype = copy_node (make_unsigned_type (oprecision));
1943 ubitsizetype = copy_node (make_unsigned_type (precision));
1946 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1948 /* Show is a sizetype, is a main type, and has no pointers to it. */
1949 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1951 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1952 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1953 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1954 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1955 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1958 /* Go down each of the types we already made and set the proper type
1959 for the sizes in them. */
1960 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1962 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE)
1965 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1966 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1969 early_type_list = 0;
1973 /* Set the extreme values of TYPE based on its precision in bits,
1974 then lay it out. Used when make_signed_type won't do
1975 because the tree code is not INTEGER_TYPE.
1976 E.g. for Pascal, when the -fsigned-char option is given. */
1979 fixup_signed_type (type)
1982 int precision = TYPE_PRECISION (type);
1984 /* We can not represent properly constants greater then
1985 2 * HOST_BITS_PER_WIDE_INT, still we need the types
1986 as they are used by i386 vector extensions and friends. */
1987 if (precision > HOST_BITS_PER_WIDE_INT * 2)
1988 precision = HOST_BITS_PER_WIDE_INT * 2;
1990 TYPE_MIN_VALUE (type)
1991 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1992 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1993 (((HOST_WIDE_INT) (-1)
1994 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1995 ? precision - HOST_BITS_PER_WIDE_INT - 1
1997 TYPE_MAX_VALUE (type)
1998 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1999 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2000 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2001 ? (((HOST_WIDE_INT) 1
2002 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2005 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2006 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2008 /* Lay out the type: set its alignment, size, etc. */
2012 /* Set the extreme values of TYPE based on its precision in bits,
2013 then lay it out. This is used both in `make_unsigned_type'
2014 and for enumeral types. */
2017 fixup_unsigned_type (type)
2020 int precision = TYPE_PRECISION (type);
2022 /* We can not represent properly constants greater then
2023 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2024 as they are used by i386 vector extensions and friends. */
2025 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2026 precision = HOST_BITS_PER_WIDE_INT * 2;
2028 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
2029 TYPE_MAX_VALUE (type)
2030 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
2031 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
2032 precision - HOST_BITS_PER_WIDE_INT > 0
2033 ? ((unsigned HOST_WIDE_INT) ~0
2034 >> (HOST_BITS_PER_WIDE_INT
2035 - (precision - HOST_BITS_PER_WIDE_INT)))
2037 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2038 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2040 /* Lay out the type: set its alignment, size, etc. */
2044 /* Find the best machine mode to use when referencing a bit field of length
2045 BITSIZE bits starting at BITPOS.
2047 The underlying object is known to be aligned to a boundary of ALIGN bits.
2048 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2049 larger than LARGEST_MODE (usually SImode).
2051 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2052 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2053 mode meeting these conditions.
2055 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2056 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2057 all the conditions. */
2060 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
2061 int bitsize, bitpos;
2063 enum machine_mode largest_mode;
2066 enum machine_mode mode;
2067 unsigned int unit = 0;
2069 /* Find the narrowest integer mode that contains the bit field. */
2070 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2071 mode = GET_MODE_WIDER_MODE (mode))
2073 unit = GET_MODE_BITSIZE (mode);
2074 if ((bitpos % unit) + bitsize <= unit)
2078 if (mode == VOIDmode
2079 /* It is tempting to omit the following line
2080 if STRICT_ALIGNMENT is true.
2081 But that is incorrect, since if the bitfield uses part of 3 bytes
2082 and we use a 4-byte mode, we could get a spurious segv
2083 if the extra 4th byte is past the end of memory.
2084 (Though at least one Unix compiler ignores this problem:
2085 that on the Sequent 386 machine. */
2086 || MIN (unit, BIGGEST_ALIGNMENT) > align
2087 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2090 if (SLOW_BYTE_ACCESS && ! volatilep)
2092 enum machine_mode wide_mode = VOIDmode, tmode;
2094 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2095 tmode = GET_MODE_WIDER_MODE (tmode))
2097 unit = GET_MODE_BITSIZE (tmode);
2098 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2099 && unit <= BITS_PER_WORD
2100 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2101 && (largest_mode == VOIDmode
2102 || unit <= GET_MODE_BITSIZE (largest_mode)))
2106 if (wide_mode != VOIDmode)
2113 #include "gt-stor-layout.h"