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 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
34 /* Set to one when set_sizetype has been called. */
35 static int sizetype_set;
37 /* List of types created before set_sizetype has been called. We do not
38 make this a GGC root since we want these nodes to be reclaimed. */
39 static tree early_type_list;
41 /* Data type for the expressions representing sizes of data types.
42 It is the first integer type laid out. */
43 tree sizetype_tab[(int) TYPE_KIND_LAST];
45 /* If nonzero, this is an upper limit on alignment of structure fields.
46 The value is measured in bits. */
47 unsigned int maximum_field_alignment;
49 /* If non-zero, the alignment of a bitstring or (power-)set value, in bits.
50 May be overridden by front-ends. */
51 unsigned int set_alignment = 0;
53 static void finalize_record_size PARAMS ((record_layout_info));
54 static void finalize_type_size PARAMS ((tree));
55 static void place_union_field PARAMS ((record_layout_info, tree));
56 extern void debug_rli PARAMS ((record_layout_info));
58 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
60 static tree pending_sizes;
62 /* Nonzero means cannot safely call expand_expr now,
63 so put variable sizes onto `pending_sizes' instead. */
65 int immediate_size_expand;
67 /* Get a list of all the objects put on the pending sizes list. */
72 tree chain = pending_sizes;
75 /* Put each SAVE_EXPR into the current function. */
76 for (t = chain; t; t = TREE_CHAIN (t))
77 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
83 /* Put a chain of objects into the pending sizes list, which must be
87 put_pending_sizes (chain)
93 pending_sizes = chain;
96 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
97 to serve as the actual size-expression for a type or decl. */
103 /* If the language-processor is to take responsibility for variable-sized
104 items (e.g., languages which have elaboration procedures like Ada),
105 just return SIZE unchanged. Likewise for self-referential sizes. */
106 if (TREE_CONSTANT (size)
107 || global_bindings_p () < 0 || contains_placeholder_p (size))
110 size = save_expr (size);
112 /* If an array with a variable number of elements is declared, and
113 the elements require destruction, we will emit a cleanup for the
114 array. That cleanup is run both on normal exit from the block
115 and in the exception-handler for the block. Normally, when code
116 is used in both ordinary code and in an exception handler it is
117 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
118 not wish to do that here; the array-size is the same in both
120 if (TREE_CODE (size) == SAVE_EXPR)
121 SAVE_EXPR_PERSISTENT_P (size) = 1;
123 if (global_bindings_p ())
125 if (TREE_CONSTANT (size))
126 error ("type size can't be explicitly evaluated");
128 error ("variable-size type declared outside of any function");
130 return size_one_node;
133 if (immediate_size_expand)
134 /* NULL_RTX is not defined; neither is the rtx type.
135 Also, we would like to pass const0_rtx here, but don't have it. */
136 expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
138 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
139 /* The front-end doesn't want us to keep a list of the expressions
140 that determine sizes for variable size objects. */
143 pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
148 #ifndef MAX_FIXED_MODE_SIZE
149 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
152 /* Return the machine mode to use for a nonscalar of SIZE bits.
153 The mode must be in class CLASS, and have exactly that many bits.
154 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
158 mode_for_size (size, class, limit)
160 enum mode_class class;
163 register enum machine_mode mode;
165 if (limit && size > MAX_FIXED_MODE_SIZE)
168 /* Get the first mode which has this size, in the specified class. */
169 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
170 mode = GET_MODE_WIDER_MODE (mode))
171 if (GET_MODE_BITSIZE (mode) == size)
177 /* Similar, except passed a tree node. */
180 mode_for_size_tree (size, class, limit)
182 enum mode_class class;
185 if (TREE_CODE (size) != INTEGER_CST
186 /* What we really want to say here is that the size can fit in a
187 host integer, but we know there's no way we'd find a mode for
188 this many bits, so there's no point in doing the precise test. */
189 || compare_tree_int (size, 1000) > 0)
192 return mode_for_size (TREE_INT_CST_LOW (size), class, limit);
195 /* Similar, but never return BLKmode; return the narrowest mode that
196 contains at least the requested number of bits. */
199 smallest_mode_for_size (size, class)
201 enum mode_class class;
203 register enum machine_mode mode;
205 /* Get the first mode which has at least this size, in the
207 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
208 mode = GET_MODE_WIDER_MODE (mode))
209 if (GET_MODE_BITSIZE (mode) >= size)
215 /* Find an integer mode of the exact same size, or BLKmode on failure. */
218 int_mode_for_mode (mode)
219 enum machine_mode mode;
221 switch (GET_MODE_CLASS (mode))
224 case MODE_PARTIAL_INT:
227 case MODE_COMPLEX_INT:
228 case MODE_COMPLEX_FLOAT:
230 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
237 /* ... fall through ... */
247 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
248 This can only be applied to objects of a sizetype. */
251 round_up (value, divisor)
255 tree arg = size_int_type (divisor, TREE_TYPE (value));
257 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
260 /* Likewise, but round down. */
263 round_down (value, divisor)
267 tree arg = size_int_type (divisor, TREE_TYPE (value));
269 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
272 /* Set the size, mode and alignment of a ..._DECL node.
273 TYPE_DECL does need this for C++.
274 Note that LABEL_DECL and CONST_DECL nodes do not need this,
275 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
276 Don't call layout_decl for them.
278 KNOWN_ALIGN is the amount of alignment we can assume this
279 decl has with no special effort. It is relevant only for FIELD_DECLs
280 and depends on the previous fields.
281 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
282 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
283 the record will be aligned to suit. */
286 layout_decl (decl, known_align)
288 unsigned int known_align;
290 register tree type = TREE_TYPE (decl);
291 register enum tree_code code = TREE_CODE (decl);
293 if (code == CONST_DECL)
295 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
296 && code != TYPE_DECL && code != FIELD_DECL)
299 if (type == error_mark_node)
300 type = void_type_node;
302 /* Usually the size and mode come from the data type without change,
303 however, the front-end may set the explicit width of the field, so its
304 size may not be the same as the size of its type. This happens with
305 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
306 also happens with other fields. For example, the C++ front-end creates
307 zero-sized fields corresponding to empty base classes, and depends on
308 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
309 size in bytes from the size in bits. If we have already set the mode,
310 don't set it again since we can be called twice for FIELD_DECLs. */
312 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
313 if (DECL_MODE (decl) == VOIDmode)
314 DECL_MODE (decl) = TYPE_MODE (type);
316 if (DECL_SIZE (decl) == 0)
318 DECL_SIZE (decl) = TYPE_SIZE (type);
319 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
322 DECL_SIZE_UNIT (decl)
323 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
326 /* Force alignment required for the data type.
327 But if the decl itself wants greater alignment, don't override that.
328 Likewise, if the decl is packed, don't override it. */
329 if (! (code == FIELD_DECL && DECL_BIT_FIELD (decl))
330 && (DECL_ALIGN (decl) == 0
331 || (! (code == FIELD_DECL && DECL_PACKED (decl))
332 && TYPE_ALIGN (type) > DECL_ALIGN (decl))))
334 DECL_ALIGN (decl) = TYPE_ALIGN (type);
335 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
338 /* For fields, set the bit field type and update the alignment. */
339 if (code == FIELD_DECL)
341 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
342 if (maximum_field_alignment != 0)
343 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
344 else if (DECL_PACKED (decl))
346 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
347 DECL_USER_ALIGN (decl) = 0;
351 /* See if we can use an ordinary integer mode for a bit-field.
352 Conditions are: a fixed size that is correct for another mode
353 and occupying a complete byte or bytes on proper boundary. */
354 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
355 && TYPE_SIZE (type) != 0
356 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
357 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
359 register enum machine_mode xmode
360 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
362 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
364 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
366 DECL_MODE (decl) = xmode;
367 DECL_BIT_FIELD (decl) = 0;
371 /* Turn off DECL_BIT_FIELD if we won't need it set. */
372 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
373 && TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
374 && known_align >= TYPE_ALIGN (type)
375 && DECL_ALIGN (decl) >= TYPE_ALIGN (type)
376 && DECL_SIZE_UNIT (decl) != 0)
377 DECL_BIT_FIELD (decl) = 0;
379 /* Evaluate nonconstant size only once, either now or as soon as safe. */
380 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
381 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
382 if (DECL_SIZE_UNIT (decl) != 0
383 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
384 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
386 /* If requested, warn about definitions of large data objects. */
388 && (code == VAR_DECL || code == PARM_DECL)
389 && ! DECL_EXTERNAL (decl))
391 tree size = DECL_SIZE_UNIT (decl);
393 if (size != 0 && TREE_CODE (size) == INTEGER_CST
394 && compare_tree_int (size, larger_than_size) > 0)
396 unsigned int size_as_int = TREE_INT_CST_LOW (size);
398 if (compare_tree_int (size, size_as_int) == 0)
399 warning_with_decl (decl, "size of `%s' is %d bytes", size_as_int);
401 warning_with_decl (decl, "size of `%s' is larger than %d bytes",
407 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
408 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
409 is to be passed to all other layout functions for this record. It is the
410 responsibility of the caller to call `free' for the storage returned.
411 Note that garbage collection is not permitted until we finish laying
415 start_record_layout (t)
418 record_layout_info rli
419 = (record_layout_info) xmalloc (sizeof (struct record_layout_info_s));
423 /* If the type has a minimum specified alignment (via an attribute
424 declaration, for example) use it -- otherwise, start with a
425 one-byte alignment. */
426 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
427 rli->unpacked_align = rli->record_align;
428 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
430 #ifdef STRUCTURE_SIZE_BOUNDARY
431 /* Packed structures don't need to have minimum size. */
432 if (! TYPE_PACKED (t))
433 rli->record_align = MAX (rli->record_align, STRUCTURE_SIZE_BOUNDARY);
436 rli->offset = size_zero_node;
437 rli->bitpos = bitsize_zero_node;
438 rli->pending_statics = 0;
439 rli->packed_maybe_necessary = 0;
444 /* These four routines perform computations that convert between
445 the offset/bitpos forms and byte and bit offsets. */
448 bit_from_pos (offset, bitpos)
451 return size_binop (PLUS_EXPR, bitpos,
452 size_binop (MULT_EXPR, convert (bitsizetype, offset),
457 byte_from_pos (offset, bitpos)
460 return size_binop (PLUS_EXPR, offset,
462 size_binop (TRUNC_DIV_EXPR, bitpos,
463 bitsize_unit_node)));
467 pos_from_byte (poffset, pbitpos, off_align, pos)
468 tree *poffset, *pbitpos;
469 unsigned int off_align;
473 = size_binop (MULT_EXPR,
475 size_binop (FLOOR_DIV_EXPR, pos,
476 bitsize_int (off_align
478 size_int (off_align / BITS_PER_UNIT));
479 *pbitpos = size_binop (MULT_EXPR,
480 size_binop (FLOOR_MOD_EXPR, pos,
481 bitsize_int (off_align / BITS_PER_UNIT)),
486 pos_from_bit (poffset, pbitpos, off_align, pos)
487 tree *poffset, *pbitpos;
488 unsigned int off_align;
491 *poffset = size_binop (MULT_EXPR,
493 size_binop (FLOOR_DIV_EXPR, pos,
494 bitsize_int (off_align))),
495 size_int (off_align / BITS_PER_UNIT));
496 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
499 /* Given a pointer to bit and byte offsets and an offset alignment,
500 normalize the offsets so they are within the alignment. */
503 normalize_offset (poffset, pbitpos, off_align)
504 tree *poffset, *pbitpos;
505 unsigned int off_align;
507 /* If the bit position is now larger than it should be, adjust it
509 if (compare_tree_int (*pbitpos, off_align) >= 0)
511 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
512 bitsize_int (off_align));
515 = size_binop (PLUS_EXPR, *poffset,
516 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
517 size_int (off_align / BITS_PER_UNIT)));
520 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
524 /* Print debugging information about the information in RLI. */
528 record_layout_info rli;
530 print_node_brief (stderr, "type", rli->t, 0);
531 print_node_brief (stderr, "\noffset", rli->offset, 0);
532 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
534 fprintf (stderr, "\nrec_align = %u, unpack_align = %u, off_align = %u\n",
535 rli->record_align, rli->unpacked_align, rli->offset_align);
536 if (rli->packed_maybe_necessary)
537 fprintf (stderr, "packed may be necessary\n");
539 if (rli->pending_statics)
541 fprintf (stderr, "pending statics:\n");
542 debug_tree (rli->pending_statics);
546 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
547 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
551 record_layout_info rli;
553 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
556 /* Returns the size in bytes allocated so far. */
559 rli_size_unit_so_far (rli)
560 record_layout_info rli;
562 return byte_from_pos (rli->offset, rli->bitpos);
565 /* Returns the size in bits allocated so far. */
568 rli_size_so_far (rli)
569 record_layout_info rli;
571 return bit_from_pos (rli->offset, rli->bitpos);
574 /* Called from place_field to handle unions. */
577 place_union_field (rli, field)
578 record_layout_info rli;
581 unsigned int desired_align;
583 layout_decl (field, 0);
585 DECL_FIELD_OFFSET (field) = size_zero_node;
586 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
587 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
589 desired_align = DECL_ALIGN (field);
591 #ifdef BIGGEST_FIELD_ALIGNMENT
592 /* Some targets (i.e. i386) limit union field alignment
593 to a lower boundary than alignment of variables unless
594 it was overridden by attribute aligned. */
595 if (! DECL_USER_ALIGN (field))
597 MIN (desired_align, (unsigned) BIGGEST_FIELD_ALIGNMENT);
600 /* Union must be at least as aligned as any field requires. */
601 rli->record_align = MAX (rli->record_align, desired_align);
603 #ifdef PCC_BITFIELD_TYPE_MATTERS
604 /* On the m88000, a bit field of declare type `int' forces the
605 entire union to have `int' alignment. */
606 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
607 rli->record_align = MAX (rli->record_align,
608 TYPE_ALIGN (TREE_TYPE (field)));
611 /* We assume the union's size will be a multiple of a byte so we don't
612 bother with BITPOS. */
613 if (TREE_CODE (rli->t) == UNION_TYPE)
614 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
615 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
616 rli->offset = fold (build (COND_EXPR, sizetype,
617 DECL_QUALIFIER (field),
618 DECL_SIZE_UNIT (field), rli->offset));
621 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
622 is a FIELD_DECL to be added after those fields already present in
623 T. (FIELD is not actually added to the TYPE_FIELDS list here;
624 callers that desire that behavior must manually perform that step.) */
627 place_field (rli, field)
628 record_layout_info rli;
631 /* The alignment required for FIELD. */
632 unsigned int desired_align;
633 /* The alignment FIELD would have if we just dropped it into the
634 record as it presently stands. */
635 unsigned int known_align;
636 unsigned int actual_align;
637 unsigned int user_align;
638 /* The type of this field. */
639 tree type = TREE_TYPE (field);
641 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
644 /* If FIELD is static, then treat it like a separate variable, not
645 really like a structure field. If it is a FUNCTION_DECL, it's a
646 method. In both cases, all we do is lay out the decl, and we do
647 it *after* the record is laid out. */
648 if (TREE_CODE (field) == VAR_DECL)
650 rli->pending_statics = tree_cons (NULL_TREE, field,
651 rli->pending_statics);
655 /* Enumerators and enum types which are local to this class need not
656 be laid out. Likewise for initialized constant fields. */
657 else if (TREE_CODE (field) != FIELD_DECL)
660 /* Unions are laid out very differently than records, so split
661 that code off to another function. */
662 else if (TREE_CODE (rli->t) != RECORD_TYPE)
664 place_union_field (rli, field);
668 /* Work out the known alignment so far. Note that A & (-A) is the
669 value of the least-significant bit in A that is one. */
670 if (! integer_zerop (rli->bitpos))
671 known_align = (tree_low_cst (rli->bitpos, 1)
672 & - tree_low_cst (rli->bitpos, 1));
673 else if (integer_zerop (rli->offset))
674 known_align = BIGGEST_ALIGNMENT;
675 else if (host_integerp (rli->offset, 1))
676 known_align = (BITS_PER_UNIT
677 * (tree_low_cst (rli->offset, 1)
678 & - tree_low_cst (rli->offset, 1)));
680 known_align = rli->offset_align;
682 /* Lay out the field so we know what alignment it needs. For a
683 packed field, use the alignment as specified, disregarding what
684 the type would want. */
685 desired_align = DECL_ALIGN (field);
686 user_align = DECL_USER_ALIGN (field);
687 layout_decl (field, known_align);
688 if (! DECL_PACKED (field))
690 desired_align = DECL_ALIGN (field);
691 user_align = DECL_USER_ALIGN (field);
694 #ifdef BIGGEST_FIELD_ALIGNMENT
695 /* Some targets (i.e. i386, VMS) limit struct field alignment
696 to a lower boundary than alignment of variables unless
697 it was overridden by attribute aligned. */
700 MIN (desired_align, (unsigned) BIGGEST_FIELD_ALIGNMENT);
702 #ifdef ADJUST_FIELD_ALIGN
703 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
706 /* Record must have at least as much alignment as any field.
707 Otherwise, the alignment of the field within the record is
709 #ifdef PCC_BITFIELD_TYPE_MATTERS
710 if (PCC_BITFIELD_TYPE_MATTERS && type != error_mark_node
711 && DECL_BIT_FIELD_TYPE (field)
712 && ! integer_zerop (TYPE_SIZE (type)))
714 /* For these machines, a zero-length field does not
715 affect the alignment of the structure as a whole.
716 It does, however, affect the alignment of the next field
717 within the structure. */
718 if (! integer_zerop (DECL_SIZE (field)))
719 rli->record_align = MAX (rli->record_align, desired_align);
720 else if (! DECL_PACKED (field))
721 desired_align = TYPE_ALIGN (type);
723 /* A named bit field of declared type `int'
724 forces the entire structure to have `int' alignment. */
725 if (DECL_NAME (field) != 0)
727 unsigned int type_align = TYPE_ALIGN (type);
729 if (maximum_field_alignment != 0)
730 type_align = MIN (type_align, maximum_field_alignment);
731 else if (DECL_PACKED (field))
732 type_align = MIN (type_align, BITS_PER_UNIT);
734 rli->record_align = MAX (rli->record_align, type_align);
736 rli->unpacked_align = MAX (rli->unpacked_align,
743 rli->record_align = MAX (rli->record_align, desired_align);
744 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
747 if (warn_packed && DECL_PACKED (field))
749 if (known_align > TYPE_ALIGN (type))
751 if (TYPE_ALIGN (type) > desired_align)
753 if (STRICT_ALIGNMENT)
754 warning_with_decl (field, "packed attribute causes inefficient alignment for `%s'");
756 warning_with_decl (field, "packed attribute is unnecessary for `%s'");
760 rli->packed_maybe_necessary = 1;
763 /* Does this field automatically have alignment it needs by virtue
764 of the fields that precede it and the record's own alignment? */
765 if (known_align < desired_align)
767 /* No, we need to skip space before this field.
768 Bump the cumulative size to multiple of field alignment. */
771 warning_with_decl (field, "padding struct to align `%s'");
773 /* If the alignment is still within offset_align, just align
775 if (desired_align < rli->offset_align)
776 rli->bitpos = round_up (rli->bitpos, desired_align);
779 /* First adjust OFFSET by the partial bits, then align. */
781 = size_binop (PLUS_EXPR, rli->offset,
783 size_binop (CEIL_DIV_EXPR, rli->bitpos,
784 bitsize_unit_node)));
785 rli->bitpos = bitsize_zero_node;
787 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
790 if (! TREE_CONSTANT (rli->offset))
791 rli->offset_align = desired_align;
795 /* Handle compatibility with PCC. Note that if the record has any
796 variable-sized fields, we need not worry about compatibility. */
797 #ifdef PCC_BITFIELD_TYPE_MATTERS
798 if (PCC_BITFIELD_TYPE_MATTERS
799 && TREE_CODE (field) == FIELD_DECL
800 && type != error_mark_node
801 && DECL_BIT_FIELD (field)
802 && ! DECL_PACKED (field)
803 && maximum_field_alignment == 0
804 && ! integer_zerop (DECL_SIZE (field))
805 && host_integerp (DECL_SIZE (field), 1)
806 && host_integerp (rli->offset, 1)
807 && host_integerp (TYPE_SIZE (type), 1))
809 unsigned int type_align = TYPE_ALIGN (type);
810 tree dsize = DECL_SIZE (field);
811 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
812 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
813 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
815 /* A bit field may not span more units of alignment of its type
816 than its type itself. Advance to next boundary if necessary. */
817 if ((((offset * BITS_PER_UNIT + bit_offset + field_size +
820 - (offset * BITS_PER_UNIT + bit_offset) / type_align)
821 > tree_low_cst (TYPE_SIZE (type), 1) / type_align)
822 rli->bitpos = round_up (rli->bitpos, type_align);
826 #ifdef BITFIELD_NBYTES_LIMITED
827 if (BITFIELD_NBYTES_LIMITED
828 && TREE_CODE (field) == FIELD_DECL
829 && type != error_mark_node
830 && DECL_BIT_FIELD_TYPE (field)
831 && ! DECL_PACKED (field)
832 && ! integer_zerop (DECL_SIZE (field))
833 && host_integerp (DECL_SIZE (field), 1)
834 && host_integerp (rli->offset, 1)
835 && host_integerp (TYPE_SIZE (type), 1))
837 unsigned int type_align = TYPE_ALIGN (type);
838 tree dsize = DECL_SIZE (field);
839 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
840 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
841 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
843 if (maximum_field_alignment != 0)
844 type_align = MIN (type_align, maximum_field_alignment);
845 /* ??? This test is opposite the test in the containing if
846 statement, so this code is unreachable currently. */
847 else if (DECL_PACKED (field))
848 type_align = MIN (type_align, BITS_PER_UNIT);
850 /* A bit field may not span the unit of alignment of its type.
851 Advance to next boundary if necessary. */
852 /* ??? This code should match the code above for the
853 PCC_BITFIELD_TYPE_MATTERS case. */
854 if ((offset * BITS_PER_UNIT + bit_offset) / type_align
855 != ((offset * BITS_PER_UNIT + bit_offset + field_size - 1)
857 rli->bitpos = round_up (rli->bitpos, type_align);
861 /* Offset so far becomes the position of this field after normalizing. */
863 DECL_FIELD_OFFSET (field) = rli->offset;
864 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
865 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
867 /* If this field ended up more aligned than we thought it would be (we
868 approximate this by seeing if its position changed), lay out the field
869 again; perhaps we can use an integral mode for it now. */
870 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
871 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
872 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
873 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
874 actual_align = BIGGEST_ALIGNMENT;
875 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
876 actual_align = (BITS_PER_UNIT
877 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
878 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
880 actual_align = DECL_OFFSET_ALIGN (field);
882 if (known_align != actual_align)
883 layout_decl (field, actual_align);
885 /* Now add size of this field to the size of the record. If the size is
886 not constant, treat the field as being a multiple of bytes and just
887 adjust the offset, resetting the bit position. Otherwise, apportion the
888 size amongst the bit position and offset. First handle the case of an
889 unspecified size, which can happen when we have an invalid nested struct
890 definition, such as struct j { struct j { int i; } }. The error message
891 is printed in finish_struct. */
892 if (DECL_SIZE (field) == 0)
894 else if (! TREE_CONSTANT (DECL_SIZE_UNIT (field)))
897 = size_binop (PLUS_EXPR, rli->offset,
899 size_binop (CEIL_DIV_EXPR, rli->bitpos,
900 bitsize_unit_node)));
902 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
903 rli->bitpos = bitsize_zero_node;
904 rli->offset_align = MIN (rli->offset_align, DECL_ALIGN (field));
908 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
913 /* Assuming that all the fields have been laid out, this function uses
914 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
915 inidicated by RLI. */
918 finalize_record_size (rli)
919 record_layout_info rli;
921 tree unpadded_size, unpadded_size_unit;
923 /* Now we want just byte and bit offsets, so set the offset alignment
924 to be a byte and then normalize. */
925 rli->offset_align = BITS_PER_UNIT;
928 /* Determine the desired alignment. */
929 #ifdef ROUND_TYPE_ALIGN
930 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
933 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
935 TYPE_USER_ALIGN (rli->t) = 1;
937 /* Compute the size so far. Be sure to allow for extra bits in the
938 size in bytes. We have guaranteed above that it will be no more
939 than a single byte. */
940 unpadded_size = rli_size_so_far (rli);
941 unpadded_size_unit = rli_size_unit_so_far (rli);
942 if (! integer_zerop (rli->bitpos))
944 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
946 /* Record the un-rounded size in the binfo node. But first we check
947 the size of TYPE_BINFO to make sure that BINFO_SIZE is available. */
948 if (TYPE_BINFO (rli->t) && TREE_VEC_LENGTH (TYPE_BINFO (rli->t)) > 6)
950 TYPE_BINFO_SIZE (rli->t) = unpadded_size;
951 TYPE_BINFO_SIZE_UNIT (rli->t) = unpadded_size_unit;
954 /* Round the size up to be a multiple of the required alignment */
955 #ifdef ROUND_TYPE_SIZE
956 TYPE_SIZE (rli->t) = ROUND_TYPE_SIZE (rli->t, unpadded_size,
957 TYPE_ALIGN (rli->t));
958 TYPE_SIZE_UNIT (rli->t)
959 = ROUND_TYPE_SIZE_UNIT (rli->t, unpadded_size_unit,
960 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
962 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
963 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
964 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
967 if (warn_padded && TREE_CONSTANT (unpadded_size)
968 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
969 warning ("padding struct size to alignment boundary");
971 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
972 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
973 && TREE_CONSTANT (unpadded_size))
977 #ifdef ROUND_TYPE_ALIGN
979 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
981 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
984 #ifdef ROUND_TYPE_SIZE
985 unpacked_size = ROUND_TYPE_SIZE (rli->t, TYPE_SIZE (rli->t),
986 rli->unpacked_align);
988 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
991 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
993 TYPE_PACKED (rli->t) = 0;
995 if (TYPE_NAME (rli->t))
999 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1000 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1002 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1004 if (STRICT_ALIGNMENT)
1005 warning ("packed attribute causes inefficient alignment for `%s'", name);
1007 warning ("packed attribute is unnecessary for `%s'", name);
1011 if (STRICT_ALIGNMENT)
1012 warning ("packed attribute causes inefficient alignment");
1014 warning ("packed attribute is unnecessary");
1020 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1023 compute_record_mode (type)
1027 enum machine_mode mode = VOIDmode;
1029 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1030 However, if possible, we use a mode that fits in a register
1031 instead, in order to allow for better optimization down the
1033 TYPE_MODE (type) = BLKmode;
1035 if (! host_integerp (TYPE_SIZE (type), 1))
1038 /* A record which has any BLKmode members must itself be
1039 BLKmode; it can't go in a register. Unless the member is
1040 BLKmode only because it isn't aligned. */
1041 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1043 unsigned HOST_WIDE_INT bitpos;
1045 if (TREE_CODE (field) != FIELD_DECL)
1048 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1049 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1050 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
1051 || ! host_integerp (bit_position (field), 1)
1052 || ! host_integerp (DECL_SIZE (field), 1))
1055 bitpos = int_bit_position (field);
1057 /* Must be BLKmode if any field crosses a word boundary,
1058 since extract_bit_field can't handle that in registers. */
1059 if (bitpos / BITS_PER_WORD
1060 != ((tree_low_cst (DECL_SIZE (field), 1) + bitpos - 1)
1062 /* But there is no problem if the field is entire words. */
1063 && tree_low_cst (DECL_SIZE (field), 1) % BITS_PER_WORD != 0)
1066 /* If this field is the whole struct, remember its mode so
1067 that, say, we can put a double in a class into a DF
1068 register instead of forcing it to live in the stack. */
1069 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1070 mode = DECL_MODE (field);
1072 #ifdef STRUCT_FORCE_BLK
1073 /* With some targets, eg. c4x, it is sub-optimal
1074 to access an aligned BLKmode structure as a scalar. */
1075 if (mode == VOIDmode && STRUCT_FORCE_BLK (field))
1077 #endif /* STRUCT_FORCE_BLK */
1080 /* If we only have one real field; use its mode. This only applies to
1081 RECORD_TYPE. This does not apply to unions. */
1082 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1083 TYPE_MODE (type) = mode;
1085 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1087 /* If structure's known alignment is less than what the scalar
1088 mode would need, and it matters, then stick with BLKmode. */
1089 if (TYPE_MODE (type) != BLKmode
1091 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1092 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1094 /* If this is the only reason this type is BLKmode, then
1095 don't force containing types to be BLKmode. */
1096 TYPE_NO_FORCE_BLK (type) = 1;
1097 TYPE_MODE (type) = BLKmode;
1101 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1105 finalize_type_size (type)
1108 /* Normally, use the alignment corresponding to the mode chosen.
1109 However, where strict alignment is not required, avoid
1110 over-aligning structures, since most compilers do not do this
1113 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1114 && (STRICT_ALIGNMENT
1115 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1116 && TREE_CODE (type) != QUAL_UNION_TYPE
1117 && TREE_CODE (type) != ARRAY_TYPE)))
1119 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1120 TYPE_USER_ALIGN (type) = 0;
1123 /* Do machine-dependent extra alignment. */
1124 #ifdef ROUND_TYPE_ALIGN
1126 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1129 /* If we failed to find a simple way to calculate the unit size
1130 of the type, find it by division. */
1131 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1132 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1133 result will fit in sizetype. We will get more efficient code using
1134 sizetype, so we force a conversion. */
1135 TYPE_SIZE_UNIT (type)
1136 = convert (sizetype,
1137 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1138 bitsize_unit_node));
1140 if (TYPE_SIZE (type) != 0)
1142 #ifdef ROUND_TYPE_SIZE
1144 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1145 TYPE_SIZE_UNIT (type)
1146 = ROUND_TYPE_SIZE_UNIT (type, TYPE_SIZE_UNIT (type),
1147 TYPE_ALIGN (type) / BITS_PER_UNIT);
1149 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1150 TYPE_SIZE_UNIT (type)
1151 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1155 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1156 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1157 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1158 if (TYPE_SIZE_UNIT (type) != 0
1159 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1160 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1162 /* Also layout any other variants of the type. */
1163 if (TYPE_NEXT_VARIANT (type)
1164 || type != TYPE_MAIN_VARIANT (type))
1167 /* Record layout info of this variant. */
1168 tree size = TYPE_SIZE (type);
1169 tree size_unit = TYPE_SIZE_UNIT (type);
1170 unsigned int align = TYPE_ALIGN (type);
1171 unsigned int user_align = TYPE_USER_ALIGN (type);
1172 enum machine_mode mode = TYPE_MODE (type);
1174 /* Copy it into all variants. */
1175 for (variant = TYPE_MAIN_VARIANT (type);
1177 variant = TYPE_NEXT_VARIANT (variant))
1179 TYPE_SIZE (variant) = size;
1180 TYPE_SIZE_UNIT (variant) = size_unit;
1181 TYPE_ALIGN (variant) = align;
1182 TYPE_USER_ALIGN (variant) = user_align;
1183 TYPE_MODE (variant) = mode;
1188 /* Do all of the work required to layout the type indicated by RLI,
1189 once the fields have been laid out. This function will call `free'
1193 finish_record_layout (rli)
1194 record_layout_info rli;
1196 /* Compute the final size. */
1197 finalize_record_size (rli);
1199 /* Compute the TYPE_MODE for the record. */
1200 compute_record_mode (rli->t);
1202 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1203 finalize_type_size (rli->t);
1205 /* Lay out any static members. This is done now because their type
1206 may use the record's type. */
1207 while (rli->pending_statics)
1209 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1210 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1217 /* Calculate the mode, size, and alignment for TYPE.
1218 For an array type, calculate the element separation as well.
1219 Record TYPE on the chain of permanent or temporary types
1220 so that dbxout will find out about it.
1222 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1223 layout_type does nothing on such a type.
1225 If the type is incomplete, its TYPE_SIZE remains zero. */
1234 /* Do nothing if type has been laid out before. */
1235 if (TYPE_SIZE (type))
1238 switch (TREE_CODE (type))
1241 /* This kind of type is the responsibility
1242 of the language-specific code. */
1245 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1246 if (TYPE_PRECISION (type) == 0)
1247 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1249 /* ... fall through ... */
1254 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1255 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1256 TREE_UNSIGNED (type) = 1;
1258 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1260 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1261 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1265 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1266 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1267 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1271 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1273 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1274 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1275 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1277 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1278 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1285 subtype = TREE_TYPE (type);
1286 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1287 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1288 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1293 /* This is an incomplete type and so doesn't have a size. */
1294 TYPE_ALIGN (type) = 1;
1295 TYPE_USER_ALIGN (type) = 0;
1296 TYPE_MODE (type) = VOIDmode;
1300 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1301 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1302 TYPE_MODE (type) = ptr_mode;
1307 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1308 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1309 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1313 case REFERENCE_TYPE:
1314 TYPE_MODE (type) = ptr_mode;
1315 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1316 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1317 TREE_UNSIGNED (type) = 1;
1318 TYPE_PRECISION (type) = POINTER_SIZE;
1323 register tree index = TYPE_DOMAIN (type);
1324 register tree element = TREE_TYPE (type);
1326 build_pointer_type (element);
1328 /* We need to know both bounds in order to compute the size. */
1329 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1330 && TYPE_SIZE (element))
1332 tree ub = TYPE_MAX_VALUE (index);
1333 tree lb = TYPE_MIN_VALUE (index);
1337 /* The initial subtraction should happen in the original type so
1338 that (possible) negative values are handled appropriately. */
1339 length = size_binop (PLUS_EXPR, size_one_node,
1341 fold (build (MINUS_EXPR,
1345 /* Special handling for arrays of bits (for Chill). */
1346 element_size = TYPE_SIZE (element);
1347 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1348 && (integer_zerop (TYPE_MAX_VALUE (element))
1349 || integer_onep (TYPE_MAX_VALUE (element)))
1350 && host_integerp (TYPE_MIN_VALUE (element), 1))
1352 HOST_WIDE_INT maxvalue
1353 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1354 HOST_WIDE_INT minvalue
1355 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1357 if (maxvalue - minvalue == 1
1358 && (maxvalue == 1 || maxvalue == 0))
1359 element_size = integer_one_node;
1362 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1363 convert (bitsizetype, length));
1365 /* If we know the size of the element, calculate the total
1366 size directly, rather than do some division thing below.
1367 This optimization helps Fortran assumed-size arrays
1368 (where the size of the array is determined at runtime)
1370 Note that we can't do this in the case where the size of
1371 the elements is one bit since TYPE_SIZE_UNIT cannot be
1372 set correctly in that case. */
1373 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1374 TYPE_SIZE_UNIT (type)
1375 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1378 /* Now round the alignment and size,
1379 using machine-dependent criteria if any. */
1381 #ifdef ROUND_TYPE_ALIGN
1383 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1385 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1388 #ifdef ROUND_TYPE_SIZE
1389 if (TYPE_SIZE (type) != 0)
1392 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1394 /* If the rounding changed the size of the type, remove any
1395 pre-calculated TYPE_SIZE_UNIT. */
1396 if (simple_cst_equal (TYPE_SIZE (type), tmp) != 1)
1397 TYPE_SIZE_UNIT (type) = NULL;
1399 TYPE_SIZE (type) = tmp;
1403 TYPE_MODE (type) = BLKmode;
1404 if (TYPE_SIZE (type) != 0
1405 /* BLKmode elements force BLKmode aggregate;
1406 else extract/store fields may lose. */
1407 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1408 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1411 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1413 if (TYPE_MODE (type) != BLKmode
1414 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1415 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1416 && TYPE_MODE (type) != BLKmode)
1418 TYPE_NO_FORCE_BLK (type) = 1;
1419 TYPE_MODE (type) = BLKmode;
1427 case QUAL_UNION_TYPE:
1430 record_layout_info rli;
1432 /* Initialize the layout information. */
1433 rli = start_record_layout (type);
1435 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1436 in the reverse order in building the COND_EXPR that denotes
1437 its size. We reverse them again later. */
1438 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1439 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1441 /* Place all the fields. */
1442 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1443 place_field (rli, field);
1445 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1446 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1448 /* Finish laying out the record. */
1449 finish_record_layout (rli);
1453 case SET_TYPE: /* Used by Chill and Pascal. */
1454 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1455 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1459 #ifndef SET_WORD_SIZE
1460 #define SET_WORD_SIZE BITS_PER_WORD
1462 unsigned int alignment
1463 = set_alignment ? set_alignment : SET_WORD_SIZE;
1465 = (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
1466 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1);
1468 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1470 if (rounded_size > (int) alignment)
1471 TYPE_MODE (type) = BLKmode;
1473 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1475 TYPE_SIZE (type) = bitsize_int (rounded_size);
1476 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1477 TYPE_ALIGN (type) = alignment;
1478 TYPE_USER_ALIGN (type) = 0;
1479 TYPE_PRECISION (type) = size_in_bits;
1484 /* The size may vary in different languages, so the language front end
1485 should fill in the size. */
1486 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1487 TYPE_USER_ALIGN (type) = 0;
1488 TYPE_MODE (type) = BLKmode;
1495 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1496 records and unions, finish_record_layout already called this
1498 if (TREE_CODE (type) != RECORD_TYPE
1499 && TREE_CODE (type) != UNION_TYPE
1500 && TREE_CODE (type) != QUAL_UNION_TYPE)
1501 finalize_type_size (type);
1503 /* If this type is created before sizetype has been permanently set,
1504 record it so set_sizetype can fix it up. */
1506 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1509 /* Create and return a type for signed integers of PRECISION bits. */
1512 make_signed_type (precision)
1515 register tree type = make_node (INTEGER_TYPE);
1517 TYPE_PRECISION (type) = precision;
1519 fixup_signed_type (type);
1523 /* Create and return a type for unsigned integers of PRECISION bits. */
1526 make_unsigned_type (precision)
1529 register tree type = make_node (INTEGER_TYPE);
1531 TYPE_PRECISION (type) = precision;
1533 fixup_unsigned_type (type);
1537 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1538 value to enable integer types to be created. */
1541 initialize_sizetypes ()
1543 tree t = make_node (INTEGER_TYPE);
1545 /* Set this so we do something reasonable for the build_int_2 calls
1547 integer_type_node = t;
1549 TYPE_MODE (t) = SImode;
1550 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1551 TYPE_USER_ALIGN (t) = 0;
1552 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1553 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1554 TREE_UNSIGNED (t) = 1;
1555 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1556 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1557 TYPE_IS_SIZETYPE (t) = 1;
1559 /* 1000 avoids problems with possible overflow and is certainly
1560 larger than any size value we'd want to be storing. */
1561 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1563 /* These two must be different nodes because of the caching done in
1566 bitsizetype = copy_node (t);
1567 integer_type_node = 0;
1570 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1571 Also update the type of any standard type's sizes made so far. */
1577 int oprecision = TYPE_PRECISION (type);
1578 /* The *bitsizetype types use a precision that avoids overflows when
1579 calculating signed sizes / offsets in bits. However, when
1580 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1582 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1583 2 * HOST_BITS_PER_WIDE_INT);
1590 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1591 sizetype = copy_node (type);
1592 TYPE_DOMAIN (sizetype) = type;
1593 TYPE_IS_SIZETYPE (sizetype) = 1;
1594 bitsizetype = make_node (INTEGER_TYPE);
1595 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1596 TYPE_PRECISION (bitsizetype) = precision;
1597 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1599 if (TREE_UNSIGNED (type))
1600 fixup_unsigned_type (bitsizetype);
1602 fixup_signed_type (bitsizetype);
1604 layout_type (bitsizetype);
1606 if (TREE_UNSIGNED (type))
1608 usizetype = sizetype;
1609 ubitsizetype = bitsizetype;
1610 ssizetype = copy_node (make_signed_type (oprecision));
1611 sbitsizetype = copy_node (make_signed_type (precision));
1615 ssizetype = sizetype;
1616 sbitsizetype = bitsizetype;
1617 usizetype = copy_node (make_unsigned_type (oprecision));
1618 ubitsizetype = copy_node (make_unsigned_type (precision));
1621 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1623 /* Show is a sizetype, is a main type, and has no pointers to it. */
1624 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1626 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1627 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1628 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1629 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1630 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1633 ggc_add_tree_root ((tree *) &sizetype_tab,
1634 sizeof sizetype_tab / sizeof (tree));
1636 /* Go down each of the types we already made and set the proper type
1637 for the sizes in them. */
1638 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1640 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE)
1643 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1644 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1647 early_type_list = 0;
1651 /* Set the extreme values of TYPE based on its precision in bits,
1652 then lay it out. Used when make_signed_type won't do
1653 because the tree code is not INTEGER_TYPE.
1654 E.g. for Pascal, when the -fsigned-char option is given. */
1657 fixup_signed_type (type)
1660 register int precision = TYPE_PRECISION (type);
1662 TYPE_MIN_VALUE (type)
1663 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1664 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1665 (((HOST_WIDE_INT) (-1)
1666 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1667 ? precision - HOST_BITS_PER_WIDE_INT - 1
1669 TYPE_MAX_VALUE (type)
1670 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1671 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1672 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1673 ? (((HOST_WIDE_INT) 1
1674 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1677 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1678 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1680 /* Lay out the type: set its alignment, size, etc. */
1684 /* Set the extreme values of TYPE based on its precision in bits,
1685 then lay it out. This is used both in `make_unsigned_type'
1686 and for enumeral types. */
1689 fixup_unsigned_type (type)
1692 register int precision = TYPE_PRECISION (type);
1694 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1695 TYPE_MAX_VALUE (type)
1696 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1697 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1698 precision - HOST_BITS_PER_WIDE_INT > 0
1699 ? ((unsigned HOST_WIDE_INT) ~0
1700 >> (HOST_BITS_PER_WIDE_INT
1701 - (precision - HOST_BITS_PER_WIDE_INT)))
1703 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1704 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1706 /* Lay out the type: set its alignment, size, etc. */
1710 /* Find the best machine mode to use when referencing a bit field of length
1711 BITSIZE bits starting at BITPOS.
1713 The underlying object is known to be aligned to a boundary of ALIGN bits.
1714 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1715 larger than LARGEST_MODE (usually SImode).
1717 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1718 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1719 mode meeting these conditions.
1721 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1722 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1723 all the conditions. */
1726 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1727 int bitsize, bitpos;
1729 enum machine_mode largest_mode;
1732 enum machine_mode mode;
1733 unsigned int unit = 0;
1735 /* Find the narrowest integer mode that contains the bit field. */
1736 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1737 mode = GET_MODE_WIDER_MODE (mode))
1739 unit = GET_MODE_BITSIZE (mode);
1740 if ((bitpos % unit) + bitsize <= unit)
1744 if (mode == VOIDmode
1745 /* It is tempting to omit the following line
1746 if STRICT_ALIGNMENT is true.
1747 But that is incorrect, since if the bitfield uses part of 3 bytes
1748 and we use a 4-byte mode, we could get a spurious segv
1749 if the extra 4th byte is past the end of memory.
1750 (Though at least one Unix compiler ignores this problem:
1751 that on the Sequent 386 machine. */
1752 || MIN (unit, BIGGEST_ALIGNMENT) > align
1753 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1756 if (SLOW_BYTE_ACCESS && ! volatilep)
1758 enum machine_mode wide_mode = VOIDmode, tmode;
1760 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1761 tmode = GET_MODE_WIDER_MODE (tmode))
1763 unit = GET_MODE_BITSIZE (tmode);
1764 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1765 && unit <= BITS_PER_WORD
1766 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1767 && (largest_mode == VOIDmode
1768 || unit <= GET_MODE_BITSIZE (largest_mode)))
1772 if (wide_mode != VOIDmode)
1779 /* Return the alignment of MODE. This will be bounded by 1 and
1780 BIGGEST_ALIGNMENT. */
1783 get_mode_alignment (mode)
1784 enum machine_mode mode;
1786 unsigned int alignment = GET_MODE_UNIT_SIZE (mode) * BITS_PER_UNIT;
1788 /* Extract the LSB of the size. */
1789 alignment = alignment & -alignment;
1791 alignment = MIN (BIGGEST_ALIGNMENT, MAX (1, alignment));
1795 /* This function is run once to initialize stor-layout.c. */
1798 init_stor_layout_once ()
1800 ggc_add_tree_root (&pending_sizes, 1);