1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 1988, 1992, 1993 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 static enum machine_mode smallest_mode_for_size PROTO((unsigned int,
53 static tree layout_record PROTO((tree));
54 static void layout_union PROTO((tree));
56 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
58 static tree pending_sizes;
60 /* Nonzero means cannot safely call expand_expr now,
61 so put variable sizes onto `pending_sizes' instead. */
63 int immediate_size_expand;
68 tree chain = pending_sizes;
71 /* Put each SAVE_EXPR into the current function. */
72 for (t = chain; t; t = TREE_CHAIN (t))
73 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
78 /* Given a size SIZE that isn't constant, return a SAVE_EXPR
79 to serve as the actual size-expression for a type or decl. */
85 size = save_expr (size);
87 /* If the language-processor is to take responsibility for variable-sized
88 items (e.g., languages which have elaboration procedures like Ada),
89 just return SIZE unchanged. */
90 if (global_bindings_p () < 0)
93 else if (global_bindings_p ())
95 if (TREE_CONSTANT (size))
96 error ("type size can't be explicitly evaluated");
98 error ("variable-size type declared outside of any function");
103 if (immediate_size_expand)
104 /* NULL_RTX is not defined; neither is the rtx type.
105 Also, we would like to pass const0_rtx here, but don't have it. */
106 expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
109 pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
114 #ifndef MAX_FIXED_MODE_SIZE
115 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
118 /* Return the machine mode to use for a nonscalar of SIZE bits.
119 The mode must be in class CLASS, and have exactly that many bits.
120 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
124 mode_for_size (size, class, limit)
126 enum mode_class class;
129 register enum machine_mode mode;
131 if (limit && size > MAX_FIXED_MODE_SIZE)
134 /* Get the first mode which has this size, in the specified class. */
135 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
136 mode = GET_MODE_WIDER_MODE (mode))
137 if (GET_MODE_BITSIZE (mode) == size)
143 /* Similar, but never return BLKmode; return the narrowest mode that
144 contains at least the requested number of bits. */
146 static enum machine_mode
147 smallest_mode_for_size (size, class)
149 enum mode_class class;
151 register enum machine_mode mode;
153 /* Get the first mode which has at least this size, in the
155 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
156 mode = GET_MODE_WIDER_MODE (mode))
157 if (GET_MODE_BITSIZE (mode) >= size)
163 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
166 round_up (value, divisor)
170 return size_binop (MULT_EXPR,
171 size_binop (CEIL_DIV_EXPR, value, size_int (divisor)),
175 /* Set the size, mode and alignment of a ..._DECL node.
176 TYPE_DECL does need this for C++.
177 Note that LABEL_DECL and CONST_DECL nodes do not need this,
178 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
179 Don't call layout_decl for them.
181 KNOWN_ALIGN is the amount of alignment we can assume this
182 decl has with no special effort. It is relevant only for FIELD_DECLs
183 and depends on the previous fields.
184 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
185 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
186 the record will be aligned to suit. */
189 layout_decl (decl, known_align)
191 unsigned known_align;
193 register tree type = TREE_TYPE (decl);
194 register enum tree_code code = TREE_CODE (decl);
195 int spec_size = DECL_FIELD_SIZE (decl);
197 if (code == CONST_DECL)
200 if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
201 && code != FIELD_DECL && code != TYPE_DECL)
204 if (type == error_mark_node)
206 type = void_type_node;
210 /* Usually the size and mode come from the data type without change. */
212 DECL_MODE (decl) = TYPE_MODE (type);
213 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
214 if (DECL_SIZE (decl) == 0)
215 DECL_SIZE (decl) = TYPE_SIZE (type);
217 if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
219 /* This is a bit-field. We don't know how to handle
220 them except for integers and enums, and front end should
221 never generate them otherwise. */
223 if (! (TREE_CODE (type) == INTEGER_TYPE
224 || TREE_CODE (type) == ENUMERAL_TYPE))
227 if (spec_size == 0 && DECL_NAME (decl) != 0)
230 /* Size is specified number of bits. */
231 DECL_SIZE (decl) = size_int (spec_size);
233 /* Force alignment required for the data type.
234 But if the decl itself wants greater alignment, don't override that.
235 Likewise, if the decl is packed, don't override it. */
236 else if (DECL_ALIGN (decl) == 0
237 || (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl)))
238 DECL_ALIGN (decl) = TYPE_ALIGN (type);
240 /* See if we can use an ordinary integer mode for a bit-field. */
241 /* Conditions are: a fixed size that is correct for another mode
242 and occupying a complete byte or bytes on proper boundary. */
243 if (code == FIELD_DECL)
245 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
246 if (maximum_field_alignment != 0)
247 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
250 if (DECL_BIT_FIELD (decl)
251 && TYPE_SIZE (type) != 0
252 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
254 register enum machine_mode xmode
255 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1);
258 && known_align % GET_MODE_ALIGNMENT (xmode) == 0)
260 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
262 DECL_MODE (decl) = xmode;
263 DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode));
264 /* This no longer needs to be accessed as a bit field. */
265 DECL_BIT_FIELD (decl) = 0;
269 /* Evaluate nonconstant size only once, either now or as soon as safe. */
270 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
271 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
274 /* Lay out a RECORD_TYPE type (a C struct).
275 This means laying out the fields, determining their positions,
276 and computing the overall size and required alignment of the record.
277 Note that if you set the TYPE_ALIGN before calling this
278 then the struct is aligned to at least that boundary.
280 If the type has basetypes, you must call layout_basetypes
281 before calling this function.
283 The return value is a list of static members of the record.
284 They still need to be laid out. */
291 #ifdef STRUCTURE_SIZE_BOUNDARY
292 unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
294 unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
296 /* These must be laid out *after* the record is. */
297 tree pending_statics = NULL_TREE;
298 /* Record size so far is CONST_SIZE + VAR_SIZE bits,
299 where CONST_SIZE is an integer
300 and VAR_SIZE is a tree expression.
301 If VAR_SIZE is null, the size is just CONST_SIZE.
302 Naturally we try to avoid using VAR_SIZE. */
303 register int const_size = 0;
304 register tree var_size = 0;
305 /* Once we start using VAR_SIZE, this is the maximum alignment
306 that we know VAR_SIZE has. */
307 register int var_align = BITS_PER_UNIT;
310 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
312 register int desired_align;
314 /* If FIELD is static, then treat it like a separate variable,
315 not really like a structure field.
316 If it is a FUNCTION_DECL, it's a method.
317 In both cases, all we do is lay out the decl,
318 and we do it *after* the record is laid out. */
320 if (TREE_STATIC (field))
322 pending_statics = tree_cons (NULL_TREE, field, pending_statics);
325 /* Enumerators and enum types which are local to this class need not
326 be laid out. Likewise for initialized constant fields. */
327 if (TREE_CODE (field) != FIELD_DECL)
330 /* Lay out the field so we know what alignment it needs.
331 For KNOWN_ALIGN, pass the number of bits from start of record
332 or some divisor of it. */
334 /* For a packed field, use the alignment as specified,
335 disregarding what the type would want. */
336 if (DECL_PACKED (field))
337 desired_align = DECL_ALIGN (field);
338 layout_decl (field, var_size ? var_align : const_size);
339 if (! DECL_PACKED (field))
340 desired_align = DECL_ALIGN (field);
341 /* Some targets (i.e. VMS) limit struct field alignment
342 to a lower boundary than alignment of variables. */
343 #ifdef BIGGEST_FIELD_ALIGNMENT
344 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
347 /* Record must have at least as much alignment as any field.
348 Otherwise, the alignment of the field within the record
351 #ifndef PCC_BITFIELD_TYPE_MATTERS
352 record_align = MAX (record_align, desired_align);
354 if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
355 && DECL_BIT_FIELD_TYPE (field)
356 && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
358 /* For these machines, a zero-length field does not
359 affect the alignment of the structure as a whole.
360 It does, however, affect the alignment of the next field
361 within the structure. */
362 if (! integer_zerop (DECL_SIZE (field)))
363 record_align = MAX (record_align, desired_align);
364 else if (! DECL_PACKED (field))
365 desired_align = TYPE_ALIGN (TREE_TYPE (field));
366 /* A named bit field of declared type `int'
367 forces the entire structure to have `int' alignment. */
368 if (DECL_NAME (field) != 0)
370 int type_align = TYPE_ALIGN (TREE_TYPE (field));
371 if (maximum_field_alignment != 0)
372 type_align = MIN (type_align, maximum_field_alignment);
374 record_align = MAX (record_align, type_align);
378 record_align = MAX (record_align, desired_align);
381 /* Does this field automatically have alignment it needs
382 by virtue of the fields that precede it and the record's
385 if (const_size % desired_align != 0
386 || (var_align % desired_align != 0
389 /* No, we need to skip space before this field.
390 Bump the cumulative size to multiple of field alignment. */
393 || var_align % desired_align == 0)
395 = CEIL (const_size, desired_align) * desired_align;
399 var_size = size_binop (PLUS_EXPR, var_size,
400 size_int (const_size));
402 var_size = round_up (var_size, desired_align);
403 var_align = MIN (var_align, desired_align);
407 #ifdef PCC_BITFIELD_TYPE_MATTERS
408 if (PCC_BITFIELD_TYPE_MATTERS
409 && TREE_CODE (field) == FIELD_DECL
410 && TREE_TYPE (field) != error_mark_node
411 && DECL_BIT_FIELD_TYPE (field)
412 && !DECL_PACKED (field)
413 && !integer_zerop (DECL_SIZE (field)))
415 int type_align = TYPE_ALIGN (TREE_TYPE (field));
416 register tree dsize = DECL_SIZE (field);
417 int field_size = TREE_INT_CST_LOW (dsize);
419 if (maximum_field_alignment != 0)
420 type_align = MIN (type_align, maximum_field_alignment);
422 /* A bit field may not span the unit of alignment of its type.
423 Advance to next boundary if necessary. */
424 /* ??? There is some uncertainty here as to what
425 should be done if type_align is less than the width of the type.
426 That can happen because the width exceeds BIGGEST_ALIGNMENT
427 or because it exceeds maximum_field_alignment. */
428 if (const_size / type_align
429 != (const_size + field_size - 1) / type_align)
430 const_size = CEIL (const_size, type_align) * type_align;
434 /* No existing machine description uses this parameter.
435 So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
436 #ifdef BITFIELD_NBYTES_LIMITED
437 if (BITFIELD_NBYTES_LIMITED
438 && TREE_CODE (field) == FIELD_DECL
439 && TREE_TYPE (field) != error_mark_node
440 && DECL_BIT_FIELD_TYPE (field)
441 && !DECL_PACKED (field)
442 && !integer_zerop (DECL_SIZE (field)))
444 int type_align = TYPE_ALIGN (TREE_TYPE (field));
445 register tree dsize = DECL_SIZE (field);
446 int field_size = TREE_INT_CST_LOW (dsize);
448 if (maximum_field_alignment != 0)
449 type_align = MIN (type_align, maximum_field_alignment);
451 /* A bit field may not span the unit of alignment of its type.
452 Advance to next boundary if necessary. */
453 if (const_size / type_align
454 != (const_size + field_size - 1) / type_align)
455 const_size = CEIL (const_size, type_align) * type_align;
459 /* Size so far becomes the position of this field. */
461 if (var_size && const_size)
462 DECL_FIELD_BITPOS (field)
463 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
465 DECL_FIELD_BITPOS (field) = var_size;
467 DECL_FIELD_BITPOS (field) = size_int (const_size);
469 /* If this field is an anonymous union,
470 give each union-member the same position as the union has.
472 ??? This is a real kludge because it makes the structure
473 of the types look strange. This feature is only used by
474 C++, which should have build_component_ref build two
475 COMPONENT_REF operations, one for the union and one for
476 the inner field. We set the offset of this field to zero
477 so that either the old or the correct method will work.
478 Setting DECL_FIELD_CONTEXT is wrong unless the inner fields are
479 moved into the type of this field, but nothing seems to break
480 by doing this. This kludge should be removed after 2.4. */
482 if (DECL_NAME (field) == 0
483 && TREE_CODE (TREE_TYPE (field)) == UNION_TYPE)
485 tree uelt = TYPE_FIELDS (TREE_TYPE (field));
486 for (; uelt; uelt = TREE_CHAIN (uelt))
488 DECL_FIELD_CONTEXT (uelt) = DECL_FIELD_CONTEXT (field);
489 DECL_FIELD_BITPOS (uelt) = DECL_FIELD_BITPOS (field);
492 DECL_FIELD_BITPOS (field) = integer_zero_node;
495 /* Now add size of this field to the size of the record. */
498 register tree dsize = DECL_SIZE (field);
500 /* This can happen when we have an invalid nested struct definition,
501 such as struct j { struct j { int i; } }. The error message is
502 printed in finish_struct. */
505 else if (TREE_CODE (dsize) == INTEGER_CST
506 && TREE_INT_CST_HIGH (dsize) == 0
507 && TREE_INT_CST_LOW (dsize) + const_size > const_size)
508 /* Use const_size if there's no overflow. */
509 const_size += TREE_INT_CST_LOW (dsize);
515 var_size = size_binop (PLUS_EXPR, var_size, dsize);
520 /* Work out the total size and alignment of the record
521 as one expression and store in the record type.
522 Round it up to a multiple of the record's alignment. */
526 TYPE_SIZE (rec) = size_int (const_size);
532 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
533 TYPE_SIZE (rec) = var_size;
536 /* Determine the desired alignment. */
537 #ifdef ROUND_TYPE_ALIGN
538 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
540 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
543 #ifdef ROUND_TYPE_SIZE
544 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
546 /* Round the size up to be a multiple of the required alignment */
547 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
550 return pending_statics;
553 /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
554 Lay out all the fields, set their positions to zero,
555 and compute the size and alignment of the union (maximum of any field).
556 Note that if you set the TYPE_ALIGN before calling this
557 then the union align is aligned to at least that boundary. */
564 #ifdef STRUCTURE_SIZE_BOUNDARY
565 unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
567 unsigned union_align = BITS_PER_UNIT;
570 /* The size of the union, based on the fields scanned so far,
571 is max (CONST_SIZE, VAR_SIZE).
572 VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
573 register int const_size = 0;
574 register tree var_size = 0;
576 /* If this is a QUAL_UNION_TYPE, we want to process the fields in
577 the reverse order in building the COND_EXPR that denotes its
578 size. We reverse them again later. */
579 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
580 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
582 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
584 /* Enums which are local to this class need not be laid out. */
585 if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
588 layout_decl (field, 0);
589 DECL_FIELD_BITPOS (field) = size_int (0);
591 /* Union must be at least as aligned as any field requires. */
593 union_align = MAX (union_align, DECL_ALIGN (field));
595 #ifdef PCC_BITFIELD_TYPE_MATTERS
596 /* On the m88000, a bit field of declare type `int'
597 forces the entire union to have `int' alignment. */
598 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
599 union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
602 if (TREE_CODE (rec) == UNION_TYPE)
604 /* Set union_size to max (decl_size, union_size).
605 There are more and less general ways to do this.
606 Use only CONST_SIZE unless forced to use VAR_SIZE. */
608 if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
610 = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
611 else if (var_size == 0)
612 var_size = DECL_SIZE (field);
614 var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
616 else if (TREE_CODE (rec) == QUAL_UNION_TYPE)
617 var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field),
619 var_size ? var_size : integer_zero_node));
622 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
623 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
625 /* Determine the ultimate size of the union (in bytes). */
626 if (NULL == var_size)
627 TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
629 else if (const_size == 0)
630 TYPE_SIZE (rec) = var_size;
632 TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
633 round_up (size_int (const_size),
636 /* Determine the desired alignment. */
637 #ifdef ROUND_TYPE_ALIGN
638 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
640 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
643 #ifdef ROUND_TYPE_SIZE
644 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
646 /* Round the size up to be a multiple of the required alignment */
647 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
651 /* Calculate the mode, size, and alignment for TYPE.
652 For an array type, calculate the element separation as well.
653 Record TYPE on the chain of permanent or temporary types
654 so that dbxout will find out about it.
656 TYPE_SIZE of a type is nonzero if the type has been laid out already.
657 layout_type does nothing on such a type.
659 If the type is incomplete, its TYPE_SIZE remains zero. */
666 tree pending_statics;
671 /* Do nothing if type has been laid out before. */
672 if (TYPE_SIZE (type))
675 /* Make sure all nodes we allocate are not momentary;
676 they must last past the current statement. */
677 old = suspend_momentary ();
679 /* If we are processing a permanent type, make nodes permanent.
680 If processing a temporary type, make it saveable, since the
681 type node itself is. This is important if the function is inline,
682 since its decls will get copied later. */
683 push_obstacks_nochange ();
684 if (allocation_temporary_p ())
686 if (TREE_PERMANENT (type))
687 end_temporary_allocation ();
689 saveable_allocation ();
692 switch (TREE_CODE (type))
695 /* This kind of type is the responsibility
696 of the languge-specific code. */
701 if (TREE_INT_CST_HIGH (TYPE_MIN_VALUE (type)) >= 0)
702 TREE_UNSIGNED (type) = 1;
704 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
706 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
710 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
711 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
715 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
717 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
718 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
719 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
721 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
725 TYPE_SIZE (type) = size_zero_node;
726 TYPE_ALIGN (type) = 1;
727 TYPE_MODE (type) = VOIDmode;
731 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (Pmode));
732 TYPE_MODE (type) = Pmode;
737 TYPE_MODE (type) = mode_for_size (2 * GET_MODE_BITSIZE (Pmode),
739 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
744 TYPE_MODE (type) = Pmode;
745 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
746 TREE_UNSIGNED (type) = 1;
747 TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type));
752 register tree index = TYPE_DOMAIN (type);
753 register tree element = TREE_TYPE (type);
755 build_pointer_type (element);
757 /* We need to know both bounds in order to compute the size. */
758 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
759 && TYPE_SIZE (element))
762 = size_binop (PLUS_EXPR, size_one_node,
763 size_binop (MINUS_EXPR, TYPE_MAX_VALUE (index),
764 TYPE_MIN_VALUE (index)));
766 TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
767 TYPE_SIZE (element));
770 /* Now round the alignment and size,
771 using machine-dependent criteria if any. */
773 #ifdef ROUND_TYPE_ALIGN
775 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
777 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
780 #ifdef ROUND_TYPE_SIZE
781 if (TYPE_SIZE (type) != 0)
783 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
786 TYPE_MODE (type) = BLKmode;
787 if (TYPE_SIZE (type) != 0
788 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
789 /* BLKmode elements force BLKmode aggregate;
790 else extract/store fields may lose. */
791 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
792 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
795 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
798 if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
799 && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
800 && TYPE_MODE (type) != BLKmode)
802 TYPE_NO_FORCE_BLK (type) = 1;
803 TYPE_MODE (type) = BLKmode;
810 pending_statics = layout_record (type);
811 TYPE_MODE (type) = BLKmode;
812 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
815 /* A record which has any BLKmode members must itself be BLKmode;
816 it can't go in a register.
817 Unless the member is BLKmode only because it isn't aligned. */
818 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
822 if (TREE_CODE (field) != FIELD_DECL)
825 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
826 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
829 if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
832 bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
834 /* Must be BLKmode if any field crosses a word boundary,
835 since extract_bit_field can't handle that in registers. */
836 if (bitpos / BITS_PER_WORD
837 != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
839 /* But there is no problem if the field is entire words. */
840 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
845 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
848 /* If structure's known alignment is less than
849 what the scalar mode would need, and it matters,
850 then stick with BLKmode. */
852 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
853 || (TYPE_ALIGN (type)
854 >= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
856 if (TYPE_MODE (type) != BLKmode)
857 /* If this is the only reason this type is BLKmode,
858 then don't force containing types to be BLKmode. */
859 TYPE_NO_FORCE_BLK (type) = 1;
860 TYPE_MODE (type) = BLKmode;
866 /* Lay out any static members. This is done now
867 because their type may use the record's type. */
868 while (pending_statics)
870 layout_decl (TREE_VALUE (pending_statics), 0);
871 pending_statics = TREE_CHAIN (pending_statics);
876 case QUAL_UNION_TYPE:
878 TYPE_MODE (type) = BLKmode;
879 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
880 /* If structure's known alignment is less than
881 what the scalar mode would need, and it matters,
882 then stick with BLKmode. */
883 && (! STRICT_ALIGNMENT
884 || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
885 || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
888 /* A union which has any BLKmode members must itself be BLKmode;
889 it can't go in a register.
890 Unless the member is BLKmode only because it isn't aligned. */
891 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
893 if (TREE_CODE (field) != FIELD_DECL)
896 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
897 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
902 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
910 case BOOLEAN_TYPE: /* store one byte/boolean for now. */
911 TYPE_MODE (type) = QImode;
912 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
913 TYPE_PRECISION (type) = 1;
914 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
918 TYPE_MODE (type) = QImode;
919 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
920 TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type));
921 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
925 /* The size may vary in different languages, so the language front end
926 should fill in the size. */
927 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
928 TYPE_MODE (type) = BLKmode;
935 /* Normally, use the alignment corresponding to the mode chosen.
936 However, where strict alignment is not required, avoid
937 over-aligning structures, since most compilers do not do this
940 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
942 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
943 && TREE_CODE (type) != QUAL_UNION_TYPE
944 && TREE_CODE (type) != ARRAY_TYPE)))
945 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
947 /* Evaluate nonconstant size only once, either now or as soon as safe. */
948 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
949 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
951 /* Also layout any other variants of the type. */
952 if (TYPE_NEXT_VARIANT (type)
953 || type != TYPE_MAIN_VARIANT (type))
956 /* Record layout info of this variant. */
957 tree size = TYPE_SIZE (type);
958 int align = TYPE_ALIGN (type);
959 enum machine_mode mode = TYPE_MODE (type);
961 /* Copy it into all variants. */
962 for (variant = TYPE_MAIN_VARIANT (type);
964 variant = TYPE_NEXT_VARIANT (variant))
966 TYPE_SIZE (variant) = size;
967 TYPE_ALIGN (variant) = align;
968 TYPE_MODE (variant) = mode;
973 resume_momentary (old);
976 /* Create and return a type for signed integers of PRECISION bits. */
979 make_signed_type (precision)
982 register tree type = make_node (INTEGER_TYPE);
984 TYPE_PRECISION (type) = precision;
986 /* Create the extreme values based on the number of bits. */
988 TYPE_MIN_VALUE (type)
989 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
990 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
991 (((HOST_WIDE_INT) (-1)
992 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
993 ? precision - HOST_BITS_PER_WIDE_INT - 1
995 TYPE_MAX_VALUE (type)
996 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
997 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
998 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
999 ? (((HOST_WIDE_INT) 1
1000 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1003 /* Give this type's extreme values this type as their type. */
1005 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1006 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1008 /* The first type made with this or `make_unsigned_type'
1009 is the type for size values. */
1016 /* Lay out the type: set its alignment, size, etc. */
1023 /* Create and return a type for unsigned integers of PRECISION bits. */
1026 make_unsigned_type (precision)
1029 register tree type = make_node (INTEGER_TYPE);
1031 TYPE_PRECISION (type) = precision;
1033 /* The first type made with this or `make_signed_type'
1034 is the type for size values. */
1041 fixup_unsigned_type (type);
1045 /* Set the extreme values of TYPE based on its precision in bits,
1046 then lay it out. Used when make_signed_type won't do
1047 because the tree code is not INTEGER_TYPE.
1048 E.g. for Pascal, when the -fsigned-char option is given. */
1051 fixup_signed_type (type)
1054 register int precision = TYPE_PRECISION (type);
1056 TYPE_MIN_VALUE (type)
1057 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1058 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1059 (((HOST_WIDE_INT) (-1)
1060 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1061 ? precision - HOST_BITS_PER_WIDE_INT - 1
1063 TYPE_MAX_VALUE (type)
1064 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1065 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1066 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1067 ? (((HOST_WIDE_INT) 1
1068 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1071 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1072 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1074 /* Lay out the type: set its alignment, size, etc. */
1079 /* Set the extreme values of TYPE based on its precision in bits,
1080 then lay it out. This is used both in `make_unsigned_type'
1081 and for enumeral types. */
1084 fixup_unsigned_type (type)
1087 register int precision = TYPE_PRECISION (type);
1089 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1090 TYPE_MAX_VALUE (type)
1091 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1092 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1093 precision - HOST_BITS_PER_WIDE_INT > 0
1094 ? ((unsigned HOST_WIDE_INT) ~0
1095 >> (HOST_BITS_PER_WIDE_INT
1096 - (precision - HOST_BITS_PER_WIDE_INT)))
1098 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1099 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1101 /* Lay out the type: set its alignment, size, etc. */
1106 /* Find the best machine mode to use when referencing a bit field of length
1107 BITSIZE bits starting at BITPOS.
1109 The underlying object is known to be aligned to a boundary of ALIGN bits.
1110 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1111 larger than LARGEST_MODE (usually SImode).
1113 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1114 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1115 mode meeting these conditions.
1117 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1118 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1119 all the conditions. */
1122 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1123 int bitsize, bitpos;
1125 enum machine_mode largest_mode;
1128 enum machine_mode mode;
1131 /* Find the narrowest integer mode that contains the bit field. */
1132 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1133 mode = GET_MODE_WIDER_MODE (mode))
1135 unit = GET_MODE_BITSIZE (mode);
1136 if (bitpos / unit == (bitpos + bitsize - 1) / unit)
1140 if (mode == MAX_MACHINE_MODE
1141 /* It is tempting to omit the following line
1142 if STRICT_ALIGNMENT is true.
1143 But that is incorrect, since if the bitfield uses part of 3 bytes
1144 and we use a 4-byte mode, we could get a spurious segv
1145 if the extra 4th byte is past the end of memory.
1146 (Though at least one Unix compiler ignores this problem:
1147 that on the Sequent 386 machine. */
1148 || MIN (unit, BIGGEST_ALIGNMENT) > align
1149 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1152 if (SLOW_BYTE_ACCESS && ! volatilep)
1154 enum machine_mode wide_mode = VOIDmode, tmode;
1156 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1157 tmode = GET_MODE_WIDER_MODE (tmode))
1159 unit = GET_MODE_BITSIZE (tmode);
1160 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1161 && unit <= BITS_PER_WORD
1162 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1163 && (largest_mode == VOIDmode
1164 || unit <= GET_MODE_BITSIZE (largest_mode)))
1168 if (wide_mode != VOIDmode)
1175 /* Save all variables describing the current status into the structure *P.
1176 This is used before starting a nested function. */
1179 save_storage_status (p)
1182 #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
1183 p->pending_sizes = pending_sizes;
1184 p->immediate_size_expand = immediate_size_expand;
1188 /* Restore all variables describing the current status from the structure *P.
1189 This is used after a nested function. */
1192 restore_storage_status (p)
1196 pending_sizes = p->pending_sizes;
1197 immediate_size_expand = p->immediate_size_expand;