1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 1988, 1992 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
27 #define CEIL(x,y) (((x) + (y) - 1) / (y))
29 /* Data type for the expressions representing sizes of data types.
30 It is the first integer type laid out.
35 /* An integer constant with value 0 whose type is sizetype. */
39 /* An integer constant with value 1 whose type is sizetype. */
43 /* If nonzero, this is an upper limit on alignment of structure fields.
44 The value is measured in bits. */
45 int maximum_field_alignment;
47 #define GET_MODE_ALIGNMENT(MODE) \
48 MIN (BIGGEST_ALIGNMENT, \
49 MAX (1, (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT)))
51 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
53 static tree pending_sizes;
55 /* Nonzero means cannot safely call expand_expr now,
56 so put variable sizes onto `pending_sizes' instead. */
58 int immediate_size_expand;
63 tree chain = pending_sizes;
66 /* Put each SAVE_EXPR into the current function. */
67 for (t = chain; t; t = TREE_CHAIN (t))
68 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
73 /* Given a size SIZE that isn't constant, return a SAVE_EXPR
74 to serve as the actual size-expression for a type or decl. */
80 size = save_expr (size);
82 if (global_bindings_p ())
84 if (TREE_CONSTANT (size))
85 error ("type size can't be explicitly evaluated");
87 error ("variable-size type declared outside of any function");
92 if (immediate_size_expand)
93 /* NULL_RTX is not defined; neither is the rtx type.
94 Also, we would like to pass const0_rtx here, but don't have it. */
95 expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
98 pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
103 #ifndef MAX_FIXED_MODE_SIZE
104 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
107 /* Return the machine mode to use for a nonscalar of SIZE bits.
108 The mode must be in class CLASS, and have exactly that many bits.
109 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
113 mode_for_size (size, class, limit)
115 enum mode_class class;
118 register enum machine_mode mode;
120 if (limit && size > MAX_FIXED_MODE_SIZE)
123 /* Get the last mode which has this size, in the specified class. */
124 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
125 mode = GET_MODE_WIDER_MODE (mode))
126 if (GET_MODE_BITSIZE (mode) == size)
132 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
135 round_up (value, divisor)
139 return size_binop (MULT_EXPR,
140 size_binop (CEIL_DIV_EXPR, value, size_int (divisor)),
144 /* Set the size, mode and alignment of a ..._DECL node.
145 TYPE_DECL does need this for C++.
146 Note that LABEL_DECL and CONST_DECL nodes do not need this,
147 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
148 Don't call layout_decl for them.
150 KNOWN_ALIGN is the amount of alignment we can assume this
151 decl has with no special effort. It is relevant only for FIELD_DECLs
152 and depends on the previous fields.
153 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
154 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
155 the record will be aligned to suit. */
158 layout_decl (decl, known_align)
160 unsigned known_align;
162 register tree type = TREE_TYPE (decl);
163 register enum tree_code code = TREE_CODE (decl);
164 int spec_size = DECL_FIELD_SIZE (decl);
166 if (code == CONST_DECL)
169 if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
170 && code != FIELD_DECL && code != TYPE_DECL)
173 if (type == error_mark_node)
175 type = void_type_node;
179 /* Usually the size and mode come from the data type without change. */
181 DECL_MODE (decl) = TYPE_MODE (type);
182 DECL_SIZE (decl) = TYPE_SIZE (type);
183 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
185 if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
187 /* This is a bit-field. We don't know how to handle
188 them except for integers and enums, and front end should
189 never generate them otherwise. */
191 if (! (TREE_CODE (type) == INTEGER_TYPE
192 || TREE_CODE (type) == ENUMERAL_TYPE))
195 if (spec_size == 0 && DECL_NAME (decl) != 0)
198 /* Size is specified number of bits. */
199 DECL_SIZE (decl) = size_int (spec_size);
201 /* Force alignment required for the data type.
202 But if the decl itself wants greater alignment, don't override that.
203 Likewise, if the decl is packed, don't override it. */
204 else if (DECL_ALIGN (decl) == 0
205 || (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl)))
206 DECL_ALIGN (decl) = TYPE_ALIGN (type);
208 /* See if we can use an ordinary integer mode for a bit-field. */
209 /* Conditions are: a fixed size that is correct for another mode
210 and occupying a complete byte or bytes on proper boundary. */
211 if (code == FIELD_DECL)
213 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
214 if (maximum_field_alignment != 0)
215 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
218 if (DECL_BIT_FIELD (decl)
219 && TYPE_SIZE (type) != 0
220 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
222 register enum machine_mode xmode
223 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1);
226 && known_align % GET_MODE_ALIGNMENT (xmode) == 0)
228 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
230 DECL_MODE (decl) = xmode;
231 DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode));
232 /* This no longer needs to be accessed as a bit field. */
233 DECL_BIT_FIELD (decl) = 0;
237 /* Evaluate nonconstant size only once, either now or as soon as safe. */
238 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
239 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
242 /* Lay out a RECORD_TYPE type (a C struct).
243 This means laying out the fields, determining their positions,
244 and computing the overall size and required alignment of the record.
245 Note that if you set the TYPE_ALIGN before calling this
246 then the struct is aligned to at least that boundary.
248 If the type has basetypes, you must call layout_basetypes
249 before calling this function.
251 The return value is a list of static members of the record.
252 They still need to be laid out. */
259 #ifdef STRUCTURE_SIZE_BOUNDARY
260 unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
262 unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
264 /* These must be laid out *after* the record is. */
265 tree pending_statics = NULL_TREE;
266 /* Record size so far is CONST_SIZE + VAR_SIZE bits,
267 where CONST_SIZE is an integer
268 and VAR_SIZE is a tree expression.
269 If VAR_SIZE is null, the size is just CONST_SIZE.
270 Naturally we try to avoid using VAR_SIZE. */
271 register int const_size = 0;
272 register tree var_size = 0;
273 /* Once we start using VAR_SIZE, this is the maximum alignment
274 that we know VAR_SIZE has. */
275 register int var_align = BITS_PER_UNIT;
278 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
280 register int desired_align;
282 /* If FIELD is static, then treat it like a separate variable,
283 not really like a structure field.
284 If it is a FUNCTION_DECL, it's a method.
285 In both cases, all we do is lay out the decl,
286 and we do it *after* the record is laid out. */
288 if (TREE_STATIC (field))
290 pending_statics = tree_cons (NULL_TREE, field, pending_statics);
293 /* Enumerators and enum types which are local to this class need not
294 be laid out. Likewise for initialized constant fields. */
295 if (TREE_CODE (field) != FIELD_DECL)
298 /* Lay out the field so we know what alignment it needs.
299 For KNOWN_ALIGN, pass the number of bits from start of record
300 or some divisor of it. */
302 /* For a packed field, use the alignment as specified,
303 disregarding what the type would want. */
304 if (DECL_PACKED (field))
305 desired_align = DECL_ALIGN (field);
306 layout_decl (field, var_size ? var_align : const_size);
307 if (! DECL_PACKED (field))
308 desired_align = DECL_ALIGN (field);
309 /* Some targets (i.e. VMS) limit struct field alignment
310 to a lower boundary than alignment of variables. */
311 #ifdef BIGGEST_FIELD_ALIGNMENT
312 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
315 /* Record must have at least as much alignment as any field.
316 Otherwise, the alignment of the field within the record
319 #ifndef PCC_BITFIELD_TYPE_MATTERS
320 record_align = MAX (record_align, desired_align);
322 if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
323 && DECL_BIT_FIELD_TYPE (field)
324 && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
326 /* For these machines, a zero-length field does not
327 affect the alignment of the structure as a whole.
328 It does, however, affect the alignment of the next field
329 within the structure. */
330 if (! integer_zerop (DECL_SIZE (field)))
331 record_align = MAX (record_align, desired_align);
332 else if (! DECL_PACKED (field))
333 desired_align = TYPE_ALIGN (TREE_TYPE (field));
334 /* A named bit field of declared type `int'
335 forces the entire structure to have `int' alignment. */
336 if (DECL_NAME (field) != 0)
338 int type_align = TYPE_ALIGN (TREE_TYPE (field));
339 if (maximum_field_alignment != 0)
340 type_align = MIN (type_align, maximum_field_alignment);
342 record_align = MAX (record_align, type_align);
346 record_align = MAX (record_align, desired_align);
349 /* Does this field automatically have alignment it needs
350 by virtue of the fields that precede it and the record's
353 if (const_size % desired_align != 0
354 || (var_align % desired_align != 0
357 /* No, we need to skip space before this field.
358 Bump the cumulative size to multiple of field alignment. */
361 || var_align % desired_align == 0)
363 = CEIL (const_size, desired_align) * desired_align;
367 var_size = size_binop (PLUS_EXPR, var_size,
368 size_int (const_size));
370 var_size = round_up (var_size, desired_align);
371 var_align = MIN (var_align, desired_align);
375 #ifdef PCC_BITFIELD_TYPE_MATTERS
376 if (PCC_BITFIELD_TYPE_MATTERS
377 && TREE_CODE (field) == FIELD_DECL
378 && TREE_TYPE (field) != error_mark_node
379 && DECL_BIT_FIELD_TYPE (field)
380 && !DECL_PACKED (field)
381 && !integer_zerop (DECL_SIZE (field)))
383 int type_align = TYPE_ALIGN (TREE_TYPE (field));
384 register tree dsize = DECL_SIZE (field);
385 int field_size = TREE_INT_CST_LOW (dsize);
387 if (maximum_field_alignment != 0)
388 type_align = MIN (type_align, maximum_field_alignment);
390 /* A bit field may not span the unit of alignment of its type.
391 Advance to next boundary if necessary. */
392 /* ??? There is some uncertainty here as to what
393 should be done if type_align is less than the width of the type.
394 That can happen because the width exceeds BIGGEST_ALIGNMENT
395 or because it exceeds maximum_field_alignment. */
396 if (const_size / type_align
397 != (const_size + field_size - 1) / type_align)
398 const_size = CEIL (const_size, type_align) * type_align;
402 /* No existing machine description uses this parameter.
403 So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
404 #ifdef BITFIELD_NBYTES_LIMITED
405 if (BITFIELD_NBYTES_LIMITED
406 && TREE_CODE (field) == FIELD_DECL
407 && TREE_TYPE (field) != error_mark_node
408 && DECL_BIT_FIELD_TYPE (field)
409 && !DECL_PACKED (field)
410 && !integer_zerop (DECL_SIZE (field)))
412 int type_align = TYPE_ALIGN (TREE_TYPE (field));
413 register tree dsize = DECL_SIZE (field);
414 int field_size = TREE_INT_CST_LOW (dsize);
416 if (maximum_field_alignment != 0)
417 type_align = MIN (type_align, maximum_field_alignment);
419 /* A bit field may not span the unit of alignment of its type.
420 Advance to next boundary if necessary. */
421 if (const_size / type_align
422 != (const_size + field_size - 1) / type_align)
423 const_size = CEIL (const_size, type_align) * type_align;
427 /* Size so far becomes the position of this field. */
429 if (var_size && const_size)
430 DECL_FIELD_BITPOS (field)
431 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
433 DECL_FIELD_BITPOS (field) = var_size;
435 DECL_FIELD_BITPOS (field) = size_int (const_size);
437 /* If this field is an anonymous union,
438 give each union-member the same position as the union has.
440 ??? This is a real kludge because it makes the structure
441 of the types look strange. This feature is only used by
442 C++, which should have build_component_ref build two
443 COMPONENT_REF operations, one for the union and one for
444 the inner field. We set the offset of this field to zero
445 so that either the old or the correct method will work.
446 Setting DECL_FIELD_CONTEXT is wrong unless the inner fields are
447 moved into the type of this field, but nothing seems to break
448 by doing this. This kludge should be removed after 2.4. */
450 if (DECL_NAME (field) == 0
451 && TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
453 tree uelt = TYPE_FIELDS (TREE_TYPE (field));
454 for (; uelt; uelt = TREE_CHAIN (uelt))
456 DECL_FIELD_CONTEXT (uelt) = DECL_FIELD_CONTEXT (field);
457 DECL_FIELD_BITPOS (uelt) = DECL_FIELD_BITPOS (field);
460 DECL_FIELD_BITPOS (field) = integer_zero_node;
463 /* Now add size of this field to the size of the record. */
466 register tree dsize = DECL_SIZE (field);
468 /* This can happen when we have an invalid nested struct definition,
469 such as struct j { struct j { int i; } }. The error message is
470 printed in finish_struct. */
473 else if (TREE_CODE (dsize) == INTEGER_CST
474 && TREE_INT_CST_HIGH (dsize) == 0
475 && TREE_INT_CST_LOW (dsize) + const_size > const_size)
476 /* Use const_size if there's no overflow. */
477 const_size += TREE_INT_CST_LOW (dsize);
483 var_size = size_binop (PLUS_EXPR, var_size, dsize);
488 /* Work out the total size and alignment of the record
489 as one expression and store in the record type.
490 Round it up to a multiple of the record's alignment. */
494 TYPE_SIZE (rec) = size_int (const_size);
500 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
501 TYPE_SIZE (rec) = var_size;
504 /* Determine the desired alignment. */
505 #ifdef ROUND_TYPE_ALIGN
506 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
508 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
511 #ifdef ROUND_TYPE_SIZE
512 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
514 /* Round the size up to be a multiple of the required alignment */
515 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
518 return pending_statics;
521 /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
522 Lay out all the fields, set their positions to zero,
523 and compute the size and alignment of the union (maximum of any field).
524 Note that if you set the TYPE_ALIGN before calling this
525 then the union align is aligned to at least that boundary. */
532 #ifdef STRUCTURE_SIZE_BOUNDARY
533 unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
535 unsigned union_align = BITS_PER_UNIT;
538 /* The size of the union, based on the fields scanned so far,
539 is max (CONST_SIZE, VAR_SIZE).
540 VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
541 register int const_size = 0;
542 register tree var_size = 0;
544 /* If this is a QUAL_UNION_TYPE, we want to process the fields in
545 the reverse order in building the COND_EXPR that denotes its
546 size. We reverse them again later. */
547 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
548 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
550 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
552 /* Enums which are local to this class need not be laid out. */
553 if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
556 layout_decl (field, 0);
557 DECL_FIELD_BITPOS (field) = size_int (0);
559 /* Union must be at least as aligned as any field requires. */
561 union_align = MAX (union_align, DECL_ALIGN (field));
563 #ifdef PCC_BITFIELD_TYPE_MATTERS
564 /* On the m88000, a bit field of declare type `int'
565 forces the entire union to have `int' alignment. */
566 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
567 union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
570 if (TREE_CODE (rec) == UNION_TYPE)
572 /* Set union_size to max (decl_size, union_size).
573 There are more and less general ways to do this.
574 Use only CONST_SIZE unless forced to use VAR_SIZE. */
576 if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
578 = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
579 else if (var_size == 0)
580 var_size = DECL_SIZE (field);
582 var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
584 else if (TREE_CODE (rec) == QUAL_UNION_TYPE)
585 var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field),
587 var_size ? var_size : integer_zero_node));
590 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
591 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
593 /* Determine the ultimate size of the union (in bytes). */
594 if (NULL == var_size)
595 TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
597 else if (const_size == 0)
598 TYPE_SIZE (rec) = var_size;
600 TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
601 round_up (size_int (const_size),
604 /* Determine the desired alignment. */
605 #ifdef ROUND_TYPE_ALIGN
606 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
608 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
611 #ifdef ROUND_TYPE_SIZE
612 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
614 /* Round the size up to be a multiple of the required alignment */
615 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
619 /* Calculate the mode, size, and alignment for TYPE.
620 For an array type, calculate the element separation as well.
621 Record TYPE on the chain of permanent or temporary types
622 so that dbxout will find out about it.
624 TYPE_SIZE of a type is nonzero if the type has been laid out already.
625 layout_type does nothing on such a type.
627 If the type is incomplete, its TYPE_SIZE remains zero. */
634 tree pending_statics;
639 /* Do nothing if type has been laid out before. */
640 if (TYPE_SIZE (type))
643 /* Make sure all nodes we allocate are not momentary;
644 they must last past the current statement. */
645 old = suspend_momentary ();
647 /* If we are processing a permanent type, make nodes permanent.
648 If processing a temporary type, make it saveable, since the
649 type node itself is. This is important if the function is inline,
650 since its decls will get copied later. */
651 push_obstacks_nochange ();
652 if (allocation_temporary_p ())
654 if (TREE_PERMANENT (type))
655 end_temporary_allocation ();
657 saveable_allocation ();
660 switch (TREE_CODE (type))
663 /* This kind of type is the responsibility
664 of the languge-specific code. */
669 if (TREE_INT_CST_HIGH (TYPE_MIN_VALUE (type)) >= 0)
670 TREE_UNSIGNED (type) = 1;
672 /* We pass 0 for the last arg of mode_for_size because otherwise
673 on the Apollo using long long causes a crash.
674 It seems better to use integer modes than to try to support
675 integer types with BLKmode. */
676 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_INT, 0);
677 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
681 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
682 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
686 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
688 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
689 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
690 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
692 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
696 TYPE_SIZE (type) = size_zero_node;
697 TYPE_ALIGN (type) = 1;
698 TYPE_MODE (type) = VOIDmode;
702 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (Pmode));
703 TYPE_MODE (type) = Pmode;
708 TYPE_MODE (type) = mode_for_size (2 * GET_MODE_BITSIZE (Pmode),
710 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
715 TYPE_MODE (type) = Pmode;
716 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
717 TREE_UNSIGNED (type) = 1;
718 TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type));
723 register tree index = TYPE_DOMAIN (type);
724 register tree element = TREE_TYPE (type);
726 build_pointer_type (element);
728 /* We need to know both bounds in order to compute the size. */
729 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
730 && TYPE_SIZE (element))
733 = size_binop (PLUS_EXPR, size_one_node,
734 size_binop (MINUS_EXPR, TYPE_MAX_VALUE (index),
735 TYPE_MIN_VALUE (index)));
737 TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
738 TYPE_SIZE (element));
741 /* Now round the alignment and size,
742 using machine-dependent criteria if any. */
744 #ifdef ROUND_TYPE_ALIGN
746 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
748 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
751 #ifdef ROUND_TYPE_SIZE
752 if (TYPE_SIZE (type) != 0)
754 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
757 TYPE_MODE (type) = BLKmode;
758 if (TYPE_SIZE (type) != 0
759 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
760 /* BLKmode elements force BLKmode aggregate;
761 else extract/store fields may lose. */
762 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
763 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
766 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
769 if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
770 && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
771 && TYPE_MODE (type) != BLKmode)
773 TYPE_NO_FORCE_BLK (type) = 1;
774 TYPE_MODE (type) = BLKmode;
781 pending_statics = layout_record (type);
782 TYPE_MODE (type) = BLKmode;
783 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
786 /* A record which has any BLKmode members must itself be BLKmode;
787 it can't go in a register.
788 Unless the member is BLKmode only because it isn't aligned. */
789 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
793 if (TREE_CODE (field) != FIELD_DECL)
796 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
797 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
800 if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
803 bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
805 /* Must be BLKmode if any field crosses a word boundary,
806 since extract_bit_field can't handle that in registers. */
807 if (bitpos / BITS_PER_WORD
808 != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
810 /* But there is no problem if the field is entire words. */
811 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
816 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
819 /* If structure's known alignment is less than
820 what the scalar mode would need, and it matters,
821 then stick with BLKmode. */
823 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
824 || (TYPE_ALIGN (type)
825 >= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
827 if (TYPE_MODE (type) != BLKmode)
828 /* If this is the only reason this type is BLKmode,
829 then don't force containing types to be BLKmode. */
830 TYPE_NO_FORCE_BLK (type) = 1;
831 TYPE_MODE (type) = BLKmode;
837 /* Lay out any static members. This is done now
838 because their type may use the record's type. */
839 while (pending_statics)
841 layout_decl (TREE_VALUE (pending_statics), 0);
842 pending_statics = TREE_CHAIN (pending_statics);
847 case QUAL_UNION_TYPE:
849 TYPE_MODE (type) = BLKmode;
850 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
851 /* If structure's known alignment is less than
852 what the scalar mode would need, and it matters,
853 then stick with BLKmode. */
854 && (! STRICT_ALIGNMENT
855 || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
856 || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
859 /* A union which has any BLKmode members must itself be BLKmode;
860 it can't go in a register.
861 Unless the member is BLKmode only because it isn't aligned. */
862 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
864 if (TREE_CODE (field) != FIELD_DECL)
867 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
868 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
873 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
881 case BOOLEAN_TYPE: /* store one byte/boolean for now. */
882 TYPE_MODE (type) = QImode;
883 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
884 TYPE_PRECISION (type) = 1;
885 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
889 TYPE_MODE (type) = QImode;
890 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
891 TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type));
892 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
896 /* The size may vary in different languages, so the language front end
897 should fill in the size. */
898 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
899 TYPE_MODE (type) = BLKmode;
906 /* Normally, use the alignment corresponding to the mode chosen.
907 However, where strict alignment is not required, avoid
908 over-aligning structures, since most compilers do not do this
911 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
913 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
914 && TREE_CODE (type) != QUAL_UNION_TYPE
915 && TREE_CODE (type) != ARRAY_TYPE)))
916 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
918 /* Evaluate nonconstant size only once, either now or as soon as safe. */
919 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
920 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
922 /* Also layout any other variants of the type. */
923 if (TYPE_NEXT_VARIANT (type)
924 || type != TYPE_MAIN_VARIANT (type))
927 /* Record layout info of this variant. */
928 tree size = TYPE_SIZE (type);
929 int align = TYPE_ALIGN (type);
930 enum machine_mode mode = TYPE_MODE (type);
932 /* Copy it into all variants. */
933 for (variant = TYPE_MAIN_VARIANT (type);
935 variant = TYPE_NEXT_VARIANT (variant))
937 TYPE_SIZE (variant) = size;
938 TYPE_ALIGN (variant) = align;
939 TYPE_MODE (variant) = mode;
944 resume_momentary (old);
947 /* Create and return a type for signed integers of PRECISION bits. */
950 make_signed_type (precision)
953 register tree type = make_node (INTEGER_TYPE);
955 TYPE_PRECISION (type) = precision;
957 /* Create the extreme values based on the number of bits. */
959 TYPE_MIN_VALUE (type)
960 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
961 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
962 (((HOST_WIDE_INT) (-1)
963 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
964 ? precision - HOST_BITS_PER_WIDE_INT - 1
966 TYPE_MAX_VALUE (type)
967 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
968 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
969 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
970 ? (((HOST_WIDE_INT) 1
971 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
974 /* Give this type's extreme values this type as their type. */
976 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
977 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
979 /* The first type made with this or `make_unsigned_type'
980 is the type for size values. */
987 /* Lay out the type: set its alignment, size, etc. */
994 /* Create and return a type for unsigned integers of PRECISION bits. */
997 make_unsigned_type (precision)
1000 register tree type = make_node (INTEGER_TYPE);
1002 TYPE_PRECISION (type) = precision;
1004 /* The first type made with this or `make_signed_type'
1005 is the type for size values. */
1012 fixup_unsigned_type (type);
1016 /* Set the extreme values of TYPE based on its precision in bits,
1017 then lay it out. Used when make_signed_type won't do
1018 because the tree code is not INTEGER_TYPE.
1019 E.g. for Pascal, when the -fsigned-char option is given. */
1022 fixup_signed_type (type)
1025 register int precision = TYPE_PRECISION (type);
1027 TYPE_MIN_VALUE (type)
1028 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1029 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1030 (((HOST_WIDE_INT) (-1)
1031 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1032 ? precision - HOST_BITS_PER_WIDE_INT - 1
1034 TYPE_MAX_VALUE (type)
1035 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1036 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1037 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1038 ? (((HOST_WIDE_INT) 1
1039 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1042 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1043 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1045 /* Lay out the type: set its alignment, size, etc. */
1050 /* Set the extreme values of TYPE based on its precision in bits,
1051 then lay it out. This is used both in `make_unsigned_type'
1052 and for enumeral types. */
1055 fixup_unsigned_type (type)
1058 register int precision = TYPE_PRECISION (type);
1060 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1061 TYPE_MAX_VALUE (type)
1062 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1063 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1064 precision - HOST_BITS_PER_WIDE_INT > 0
1065 ? ((unsigned HOST_WIDE_INT) ~0
1066 >> (HOST_BITS_PER_WIDE_INT
1067 - (precision - HOST_BITS_PER_WIDE_INT)))
1069 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1070 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1072 /* Lay out the type: set its alignment, size, etc. */
1077 /* Find the best machine mode to use when referencing a bit field of length
1078 BITSIZE bits starting at BITPOS.
1080 The underlying object is known to be aligned to a boundary of ALIGN bits.
1081 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1082 larger than LARGEST_MODE (usually SImode).
1084 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1085 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1086 mode meeting these conditions.
1088 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1089 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1090 all the conditions. */
1093 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1094 int bitsize, bitpos;
1096 enum machine_mode largest_mode;
1099 enum machine_mode mode;
1102 /* Find the narrowest integer mode that contains the bit field. */
1103 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1104 mode = GET_MODE_WIDER_MODE (mode))
1106 unit = GET_MODE_BITSIZE (mode);
1107 if (bitpos / unit == (bitpos + bitsize - 1) / unit)
1111 if (mode == MAX_MACHINE_MODE
1112 /* It is tempting to omit the following line
1113 if STRICT_ALIGNMENT is true.
1114 But that is incorrect, since if the bitfield uses part of 3 bytes
1115 and we use a 4-byte mode, we could get a spurious segv
1116 if the extra 4th byte is past the end of memory.
1117 (Though at least one Unix compiler ignores this problem:
1118 that on the Sequent 386 machine. */
1119 || MIN (unit, BIGGEST_ALIGNMENT) > align
1120 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1123 if (SLOW_BYTE_ACCESS && ! volatilep)
1125 enum machine_mode wide_mode = VOIDmode, tmode;
1127 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1128 tmode = GET_MODE_WIDER_MODE (tmode))
1130 unit = GET_MODE_BITSIZE (tmode);
1131 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1132 && unit <= BITS_PER_WORD
1133 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1134 && (largest_mode == VOIDmode
1135 || unit <= GET_MODE_BITSIZE (largest_mode)))
1139 if (wide_mode != VOIDmode)
1146 /* Save all variables describing the current status into the structure *P.
1147 This is used before starting a nested function. */
1150 save_storage_status (p)
1153 #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
1154 p->pending_sizes = pending_sizes;
1155 p->immediate_size_expand = immediate_size_expand;
1159 /* Restore all variables describing the current status from the structure *P.
1160 This is used after a nested function. */
1163 restore_storage_status (p)
1167 pending_sizes = p->pending_sizes;
1168 immediate_size_expand = p->immediate_size_expand;