1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 88, 92, 93, 94, 95, 1996 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, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
30 #define CEIL(x,y) (((x) + (y) - 1) / (y))
32 /* Data type for the expressions representing sizes of data types.
33 It is the first integer type laid out.
38 /* An integer constant with value 0 whose type is sizetype. */
42 /* An integer constant with value 1 whose type is sizetype. */
46 /* If nonzero, this is an upper limit on alignment of structure fields.
47 The value is measured in bits. */
48 int maximum_field_alignment;
50 /* If non-zero, the alignment of a bitstring or (power-)set value, in bits.
51 May be overridden by front-ends. */
52 int set_alignment = 0;
54 static enum machine_mode smallest_mode_for_size PROTO((unsigned int,
56 static tree layout_record PROTO((tree));
57 static void layout_union PROTO((tree));
59 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
61 static tree pending_sizes;
63 /* Nonzero means cannot safely call expand_expr now,
64 so put variable sizes onto `pending_sizes' instead. */
66 int immediate_size_expand;
71 tree chain = pending_sizes;
74 /* Put each SAVE_EXPR into the current function. */
75 for (t = chain; t; t = TREE_CHAIN (t))
76 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
82 put_pending_sizes (chain)
88 pending_sizes = chain;
91 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
92 to serve as the actual size-expression for a type or decl. */
98 /* If the language-processor is to take responsibility for variable-sized
99 items (e.g., languages which have elaboration procedures like Ada),
100 just return SIZE unchanged. Likewise for self-referential sizes. */
101 if (TREE_CONSTANT (size)
102 || global_bindings_p () < 0 || contains_placeholder_p (size))
105 size = save_expr (size);
107 if (global_bindings_p ())
109 if (TREE_CONSTANT (size))
110 error ("type size can't be explicitly evaluated");
112 error ("variable-size type declared outside of any function");
117 if (immediate_size_expand)
118 /* NULL_RTX is not defined; neither is the rtx type.
119 Also, we would like to pass const0_rtx here, but don't have it. */
120 expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
123 pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
128 #ifndef MAX_FIXED_MODE_SIZE
129 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
132 /* Return the machine mode to use for a nonscalar of SIZE bits.
133 The mode must be in class CLASS, and have exactly that many bits.
134 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
138 mode_for_size (size, class, limit)
140 enum mode_class class;
143 register enum machine_mode mode;
145 if (limit && size > MAX_FIXED_MODE_SIZE)
148 /* Get the first mode which has this size, in the specified class. */
149 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
150 mode = GET_MODE_WIDER_MODE (mode))
151 if (GET_MODE_BITSIZE (mode) == size)
157 /* Similar, but never return BLKmode; return the narrowest mode that
158 contains at least the requested number of bits. */
160 static enum machine_mode
161 smallest_mode_for_size (size, class)
163 enum mode_class class;
165 register enum machine_mode mode;
167 /* Get the first mode which has at least this size, in the
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 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
180 round_up (value, divisor)
184 return size_binop (MULT_EXPR,
185 size_binop (CEIL_DIV_EXPR, value, size_int (divisor)),
189 /* Set the size, mode and alignment of a ..._DECL node.
190 TYPE_DECL does need this for C++.
191 Note that LABEL_DECL and CONST_DECL nodes do not need this,
192 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
193 Don't call layout_decl for them.
195 KNOWN_ALIGN is the amount of alignment we can assume this
196 decl has with no special effort. It is relevant only for FIELD_DECLs
197 and depends on the previous fields.
198 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
199 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
200 the record will be aligned to suit. */
203 layout_decl (decl, known_align)
205 unsigned known_align;
207 register tree type = TREE_TYPE (decl);
208 register enum tree_code code = TREE_CODE (decl);
209 int spec_size = DECL_FIELD_SIZE (decl);
211 if (code == CONST_DECL)
214 if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
215 && code != FIELD_DECL && code != TYPE_DECL)
218 if (type == error_mark_node)
220 type = void_type_node;
224 /* Usually the size and mode come from the data type without change. */
226 DECL_MODE (decl) = TYPE_MODE (type);
227 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
228 if (DECL_SIZE (decl) == 0)
229 DECL_SIZE (decl) = TYPE_SIZE (type);
231 if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
233 if (spec_size == 0 && DECL_NAME (decl) != 0)
236 /* Size is specified number of bits. */
237 DECL_SIZE (decl) = size_int (spec_size);
239 /* Force alignment required for the data type.
240 But if the decl itself wants greater alignment, don't override that.
241 Likewise, if the decl is packed, don't override it. */
242 else if (DECL_ALIGN (decl) == 0
243 || (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl)))
244 DECL_ALIGN (decl) = TYPE_ALIGN (type);
246 /* See if we can use an ordinary integer mode for a bit-field. */
247 /* Conditions are: a fixed size that is correct for another mode
248 and occupying a complete byte or bytes on proper boundary. */
249 if (code == FIELD_DECL)
251 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
252 if (maximum_field_alignment != 0)
253 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
254 else if (DECL_PACKED (decl))
255 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
258 if (DECL_BIT_FIELD (decl)
259 && TYPE_SIZE (type) != 0
260 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
261 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
263 register enum machine_mode xmode
264 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1);
267 && known_align % GET_MODE_ALIGNMENT (xmode) == 0)
269 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
271 DECL_MODE (decl) = xmode;
272 DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode));
273 /* This no longer needs to be accessed as a bit field. */
274 DECL_BIT_FIELD (decl) = 0;
278 /* Turn off DECL_BIT_FIELD if we won't need it set. */
279 if (DECL_BIT_FIELD (decl) && TYPE_MODE (type) == BLKmode
280 && known_align % TYPE_ALIGN (type) == 0
281 && DECL_SIZE (decl) != 0
282 && (TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST
283 || (TREE_INT_CST_LOW (DECL_SIZE (decl)) % BITS_PER_UNIT) == 0)
284 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
285 DECL_BIT_FIELD (decl) = 0;
287 /* Evaluate nonconstant size only once, either now or as soon as safe. */
288 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
289 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
292 /* Lay out a RECORD_TYPE type (a C struct).
293 This means laying out the fields, determining their positions,
294 and computing the overall size and required alignment of the record.
295 Note that if you set the TYPE_ALIGN before calling this
296 then the struct is aligned to at least that boundary.
298 If the type has basetypes, you must call layout_basetypes
299 before calling this function.
301 The return value is a list of static members of the record.
302 They still need to be laid out. */
309 #ifdef STRUCTURE_SIZE_BOUNDARY
310 unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
312 unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
314 /* These must be laid out *after* the record is. */
315 tree pending_statics = NULL_TREE;
316 /* Record size so far is CONST_SIZE + VAR_SIZE bits,
317 where CONST_SIZE is an integer
318 and VAR_SIZE is a tree expression.
319 If VAR_SIZE is null, the size is just CONST_SIZE.
320 Naturally we try to avoid using VAR_SIZE. */
321 register HOST_WIDE_INT const_size = 0;
322 register tree var_size = 0;
323 /* Once we start using VAR_SIZE, this is the maximum alignment
324 that we know VAR_SIZE has. */
325 register int var_align = BITS_PER_UNIT;
328 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
330 register int known_align = var_size ? var_align : const_size;
331 register int desired_align;
333 /* If FIELD is static, then treat it like a separate variable,
334 not really like a structure field.
335 If it is a FUNCTION_DECL, it's a method.
336 In both cases, all we do is lay out the decl,
337 and we do it *after* the record is laid out. */
339 if (TREE_CODE (field) == VAR_DECL)
341 pending_statics = tree_cons (NULL_TREE, field, pending_statics);
344 /* Enumerators and enum types which are local to this class need not
345 be laid out. Likewise for initialized constant fields. */
346 if (TREE_CODE (field) != FIELD_DECL)
349 /* Lay out the field so we know what alignment it needs.
350 For a packed field, use the alignment as specified,
351 disregarding what the type would want. */
352 if (DECL_PACKED (field))
353 desired_align = DECL_ALIGN (field);
354 layout_decl (field, known_align);
355 if (! DECL_PACKED (field))
356 desired_align = DECL_ALIGN (field);
357 /* Some targets (i.e. VMS) limit struct field alignment
358 to a lower boundary than alignment of variables. */
359 #ifdef BIGGEST_FIELD_ALIGNMENT
360 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
362 #ifdef ADJUST_FIELD_ALIGN
363 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
366 /* Record must have at least as much alignment as any field.
367 Otherwise, the alignment of the field within the record
370 #ifndef PCC_BITFIELD_TYPE_MATTERS
371 record_align = MAX (record_align, desired_align);
373 if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
374 && DECL_BIT_FIELD_TYPE (field)
375 && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
377 /* For these machines, a zero-length field does not
378 affect the alignment of the structure as a whole.
379 It does, however, affect the alignment of the next field
380 within the structure. */
381 if (! integer_zerop (DECL_SIZE (field)))
382 record_align = MAX (record_align, desired_align);
383 else if (! DECL_PACKED (field))
384 desired_align = TYPE_ALIGN (TREE_TYPE (field));
385 /* A named bit field of declared type `int'
386 forces the entire structure to have `int' alignment. */
387 if (DECL_NAME (field) != 0)
389 int type_align = TYPE_ALIGN (TREE_TYPE (field));
390 if (maximum_field_alignment != 0)
391 type_align = MIN (type_align, maximum_field_alignment);
392 else if (TYPE_PACKED (rec))
393 type_align = MIN (type_align, BITS_PER_UNIT);
395 record_align = MAX (record_align, type_align);
399 record_align = MAX (record_align, desired_align);
402 /* Does this field automatically have alignment it needs
403 by virtue of the fields that precede it and the record's
406 if (const_size % desired_align != 0
407 || (var_align % desired_align != 0
410 /* No, we need to skip space before this field.
411 Bump the cumulative size to multiple of field alignment. */
414 || var_align % desired_align == 0)
416 = CEIL (const_size, desired_align) * desired_align;
420 var_size = size_binop (PLUS_EXPR, var_size,
421 size_int (const_size));
423 var_size = round_up (var_size, desired_align);
424 var_align = MIN (var_align, desired_align);
428 #ifdef PCC_BITFIELD_TYPE_MATTERS
429 if (PCC_BITFIELD_TYPE_MATTERS
430 && TREE_CODE (field) == FIELD_DECL
431 && TREE_TYPE (field) != error_mark_node
432 && DECL_BIT_FIELD_TYPE (field)
433 && !DECL_PACKED (field)
434 && maximum_field_alignment == 0
435 && !integer_zerop (DECL_SIZE (field)))
437 int type_align = TYPE_ALIGN (TREE_TYPE (field));
438 register tree dsize = DECL_SIZE (field);
439 int field_size = TREE_INT_CST_LOW (dsize);
441 /* A bit field may not span the unit of alignment of its type.
442 Advance to next boundary if necessary. */
443 /* ??? There is some uncertainty here as to what
444 should be done if type_align is less than the width of the type.
445 That can happen because the width exceeds BIGGEST_ALIGNMENT
446 or because it exceeds maximum_field_alignment. */
447 if (const_size / type_align
448 != (const_size + MIN (field_size, type_align) - 1) / type_align)
449 const_size = CEIL (const_size, type_align) * type_align;
453 /* No existing machine description uses this parameter.
454 So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
455 #ifdef BITFIELD_NBYTES_LIMITED
456 if (BITFIELD_NBYTES_LIMITED
457 && TREE_CODE (field) == FIELD_DECL
458 && TREE_TYPE (field) != error_mark_node
459 && DECL_BIT_FIELD_TYPE (field)
460 && !DECL_PACKED (field)
461 && !integer_zerop (DECL_SIZE (field)))
463 int type_align = TYPE_ALIGN (TREE_TYPE (field));
464 register tree dsize = DECL_SIZE (field);
465 int field_size = TREE_INT_CST_LOW (dsize);
467 if (maximum_field_alignment != 0)
468 type_align = MIN (type_align, maximum_field_alignment);
469 else if (TYPE_PACKED (rec))
470 type_align = MIN (type_align, BITS_PER_UNIT);
472 /* A bit field may not span the unit of alignment of its type.
473 Advance to next boundary if necessary. */
474 if (const_size / type_align
475 != (const_size + field_size - 1) / type_align)
476 const_size = CEIL (const_size, type_align) * type_align;
480 /* Size so far becomes the position of this field. */
482 if (var_size && const_size)
483 DECL_FIELD_BITPOS (field)
484 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
486 DECL_FIELD_BITPOS (field) = var_size;
489 DECL_FIELD_BITPOS (field) = size_int (const_size);
491 /* If this field ended up more aligned than we thought it
492 would be (we approximate this by seeing if its position
493 changed), lay out the field again; perhaps we can use an
494 integral mode for it now. */
495 if (known_align != const_size)
496 layout_decl (field, const_size);
499 /* Now add size of this field to the size of the record. */
502 register tree dsize = DECL_SIZE (field);
504 /* This can happen when we have an invalid nested struct definition,
505 such as struct j { struct j { int i; } }. The error message is
506 printed in finish_struct. */
509 else if (TREE_CODE (dsize) == INTEGER_CST
510 && ! TREE_CONSTANT_OVERFLOW (dsize)
511 && TREE_INT_CST_HIGH (dsize) == 0
512 && TREE_INT_CST_LOW (dsize) + const_size >= const_size)
513 /* Use const_size if there's no overflow. */
514 const_size += TREE_INT_CST_LOW (dsize);
520 var_size = size_binop (PLUS_EXPR, var_size, dsize);
525 /* Work out the total size and alignment of the record
526 as one expression and store in the record type.
527 Round it up to a multiple of the record's alignment. */
531 TYPE_SIZE (rec) = size_int (const_size);
537 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
538 TYPE_SIZE (rec) = var_size;
541 /* Determine the desired alignment. */
542 #ifdef ROUND_TYPE_ALIGN
543 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
545 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
548 #ifdef ROUND_TYPE_SIZE
549 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
551 /* Round the size up to be a multiple of the required alignment */
552 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
555 return pending_statics;
558 /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
559 Lay out all the fields, set their positions to zero,
560 and compute the size and alignment of the union (maximum of any field).
561 Note that if you set the TYPE_ALIGN before calling this
562 then the union align is aligned to at least that boundary. */
569 #ifdef STRUCTURE_SIZE_BOUNDARY
570 unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
572 unsigned union_align = BITS_PER_UNIT;
575 /* The size of the union, based on the fields scanned so far,
576 is max (CONST_SIZE, VAR_SIZE).
577 VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
578 register int const_size = 0;
579 register tree var_size = 0;
581 /* If this is a QUAL_UNION_TYPE, we want to process the fields in
582 the reverse order in building the COND_EXPR that denotes its
583 size. We reverse them again later. */
584 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
585 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
587 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
589 /* Enums which are local to this class need not be laid out. */
590 if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
593 layout_decl (field, 0);
594 DECL_FIELD_BITPOS (field) = size_int (0);
596 /* Union must be at least as aligned as any field requires. */
598 union_align = MAX (union_align, DECL_ALIGN (field));
600 #ifdef PCC_BITFIELD_TYPE_MATTERS
601 /* On the m88000, a bit field of declare type `int'
602 forces the entire union to have `int' alignment. */
603 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
604 union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
607 if (TREE_CODE (rec) == UNION_TYPE)
609 /* Set union_size to max (decl_size, union_size).
610 There are more and less general ways to do this.
611 Use only CONST_SIZE unless forced to use VAR_SIZE. */
613 if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
615 = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
616 else if (var_size == 0)
617 var_size = DECL_SIZE (field);
619 var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
621 else if (TREE_CODE (rec) == QUAL_UNION_TYPE)
622 var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field),
624 var_size ? var_size : integer_zero_node));
627 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
628 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
630 /* Determine the ultimate size of the union (in bytes). */
631 if (NULL == var_size)
632 TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
634 else if (const_size == 0)
635 TYPE_SIZE (rec) = var_size;
637 TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
638 round_up (size_int (const_size),
641 /* Determine the desired alignment. */
642 #ifdef ROUND_TYPE_ALIGN
643 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
645 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
648 #ifdef ROUND_TYPE_SIZE
649 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
651 /* Round the size up to be a multiple of the required alignment */
652 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
656 /* Calculate the mode, size, and alignment for TYPE.
657 For an array type, calculate the element separation as well.
658 Record TYPE on the chain of permanent or temporary types
659 so that dbxout will find out about it.
661 TYPE_SIZE of a type is nonzero if the type has been laid out already.
662 layout_type does nothing on such a type.
664 If the type is incomplete, its TYPE_SIZE remains zero. */
671 tree pending_statics;
676 /* Do nothing if type has been laid out before. */
677 if (TYPE_SIZE (type))
680 /* Make sure all nodes we allocate are not momentary;
681 they must last past the current statement. */
682 old = suspend_momentary ();
684 /* Put all our nodes into the same obstack as the type. Also,
685 make expressions saveable (this is a no-op for permanent types). */
687 push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type));
688 saveable_allocation ();
690 switch (TREE_CODE (type))
693 /* This kind of type is the responsibility
694 of the language-specific code. */
700 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
701 && tree_int_cst_sgn (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 (POINTER_SIZE);
732 TYPE_MODE (type) = ptr_mode;
737 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
738 TYPE_SIZE (type) = size_int (2 * POINTER_SIZE);
743 TYPE_MODE (type) = ptr_mode;
744 TYPE_SIZE (type) = size_int (POINTER_SIZE);
745 TREE_UNSIGNED (type) = 1;
746 TYPE_PRECISION (type) = POINTER_SIZE;
751 register tree index = TYPE_DOMAIN (type);
752 register tree element = TREE_TYPE (type);
754 build_pointer_type (element);
756 /* We need to know both bounds in order to compute the size. */
757 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
758 && TYPE_SIZE (element))
760 tree ub = TYPE_MAX_VALUE (index);
761 tree lb = TYPE_MIN_VALUE (index);
764 /* If UB is max (lb - 1, x), remove the MAX_EXPR since the
765 test for negative below covers it. */
766 if (TREE_CODE (ub) == MAX_EXPR
767 && TREE_CODE (TREE_OPERAND (ub, 0)) == MINUS_EXPR
768 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 0), 1))
769 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 0), 0),
771 ub = TREE_OPERAND (ub, 1);
772 else if (TREE_CODE (ub) == MAX_EXPR
773 && TREE_CODE (TREE_OPERAND (ub, 1)) == MINUS_EXPR
774 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 1), 1))
775 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 1),
778 ub = TREE_OPERAND (ub, 0);
780 length = size_binop (PLUS_EXPR, size_one_node,
781 size_binop (MINUS_EXPR, ub, lb));
783 /* If neither bound is a constant and sizetype is signed, make
784 sure the size is never negative. We should really do this
785 if *either* bound is non-constant, but this is the best
786 compromise between C and Ada. */
787 if (! TREE_UNSIGNED (sizetype)
788 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
789 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
790 length = size_binop (MAX_EXPR, length, size_zero_node);
792 TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
793 TYPE_SIZE (element));
796 /* Now round the alignment and size,
797 using machine-dependent criteria if any. */
799 #ifdef ROUND_TYPE_ALIGN
801 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
803 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
806 #ifdef ROUND_TYPE_SIZE
807 if (TYPE_SIZE (type) != 0)
809 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
812 TYPE_MODE (type) = BLKmode;
813 if (TYPE_SIZE (type) != 0
814 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
815 /* BLKmode elements force BLKmode aggregate;
816 else extract/store fields may lose. */
817 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
818 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
821 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
824 if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
825 && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
826 && TYPE_MODE (type) != BLKmode)
828 TYPE_NO_FORCE_BLK (type) = 1;
829 TYPE_MODE (type) = BLKmode;
836 pending_statics = layout_record (type);
837 TYPE_MODE (type) = BLKmode;
838 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
841 /* A record which has any BLKmode members must itself be BLKmode;
842 it can't go in a register.
843 Unless the member is BLKmode only because it isn't aligned. */
844 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
848 if (TREE_CODE (field) != FIELD_DECL)
851 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
852 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
855 if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
858 bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
860 /* Must be BLKmode if any field crosses a word boundary,
861 since extract_bit_field can't handle that in registers. */
862 if (bitpos / BITS_PER_WORD
863 != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
865 /* But there is no problem if the field is entire words. */
866 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
871 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
874 /* If structure's known alignment is less than
875 what the scalar mode would need, and it matters,
876 then stick with BLKmode. */
878 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
879 || (TYPE_ALIGN (type)
880 >= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
882 if (TYPE_MODE (type) != BLKmode)
883 /* If this is the only reason this type is BLKmode,
884 then don't force containing types to be BLKmode. */
885 TYPE_NO_FORCE_BLK (type) = 1;
886 TYPE_MODE (type) = BLKmode;
892 /* Lay out any static members. This is done now
893 because their type may use the record's type. */
894 while (pending_statics)
896 layout_decl (TREE_VALUE (pending_statics), 0);
897 pending_statics = TREE_CHAIN (pending_statics);
902 case QUAL_UNION_TYPE:
904 TYPE_MODE (type) = BLKmode;
905 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
906 /* If structure's known alignment is less than
907 what the scalar mode would need, and it matters,
908 then stick with BLKmode. */
909 && (! STRICT_ALIGNMENT
910 || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
911 || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
914 /* A union which has any BLKmode members must itself be BLKmode;
915 it can't go in a register.
916 Unless the member is BLKmode only because it isn't aligned. */
917 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
919 if (TREE_CODE (field) != FIELD_DECL)
922 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
923 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
928 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
935 /* Pascal and Chill types */
936 case BOOLEAN_TYPE: /* store one byte/boolean for now. */
937 TYPE_MODE (type) = QImode;
938 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
939 TYPE_PRECISION (type) = 1;
940 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
941 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
942 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
943 TREE_UNSIGNED (type) = 1;
947 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
948 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
952 #ifndef SET_WORD_SIZE
953 #define SET_WORD_SIZE BITS_PER_WORD
955 int alignment = set_alignment ? set_alignment : SET_WORD_SIZE;
957 TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
958 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1;
960 = ((size_in_bits + alignment - 1) / alignment) * alignment;
961 if (rounded_size > alignment)
962 TYPE_MODE (type) = BLKmode;
964 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
965 TYPE_SIZE (type) = size_int (rounded_size);
966 TYPE_ALIGN (type) = alignment;
967 TYPE_PRECISION (type) = size_in_bits;
972 /* The size may vary in different languages, so the language front end
973 should fill in the size. */
974 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
975 TYPE_MODE (type) = BLKmode;
982 /* Normally, use the alignment corresponding to the mode chosen.
983 However, where strict alignment is not required, avoid
984 over-aligning structures, since most compilers do not do this
987 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
989 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
990 && TREE_CODE (type) != QUAL_UNION_TYPE
991 && TREE_CODE (type) != ARRAY_TYPE)))
992 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
994 /* Evaluate nonconstant size only once, either now or as soon as safe. */
995 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
996 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
998 /* Also layout any other variants of the type. */
999 if (TYPE_NEXT_VARIANT (type)
1000 || type != TYPE_MAIN_VARIANT (type))
1003 /* Record layout info of this variant. */
1004 tree size = TYPE_SIZE (type);
1005 int align = TYPE_ALIGN (type);
1006 enum machine_mode mode = TYPE_MODE (type);
1008 /* Copy it into all variants. */
1009 for (variant = TYPE_MAIN_VARIANT (type);
1011 variant = TYPE_NEXT_VARIANT (variant))
1013 TYPE_SIZE (variant) = size;
1014 TYPE_ALIGN (variant) = align;
1015 TYPE_MODE (variant) = mode;
1020 resume_momentary (old);
1023 /* Create and return a type for signed integers of PRECISION bits. */
1026 make_signed_type (precision)
1029 register tree type = make_node (INTEGER_TYPE);
1031 TYPE_PRECISION (type) = precision;
1033 /* Create the extreme values based on the number of bits. */
1035 TYPE_MIN_VALUE (type)
1036 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1037 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1038 (((HOST_WIDE_INT) (-1)
1039 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1040 ? precision - HOST_BITS_PER_WIDE_INT - 1
1042 TYPE_MAX_VALUE (type)
1043 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1044 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1045 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1046 ? (((HOST_WIDE_INT) 1
1047 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1050 /* Give this type's extreme values this type as their type. */
1052 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1053 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1055 /* The first type made with this or `make_unsigned_type'
1056 is the type for size values. */
1063 /* Lay out the type: set its alignment, size, etc. */
1070 /* Create and return a type for unsigned integers of PRECISION bits. */
1073 make_unsigned_type (precision)
1076 register tree type = make_node (INTEGER_TYPE);
1078 TYPE_PRECISION (type) = precision;
1080 /* The first type made with this or `make_signed_type'
1081 is the type for size values. */
1088 fixup_unsigned_type (type);
1092 /* Set the extreme values of TYPE based on its precision in bits,
1093 then lay it out. Used when make_signed_type won't do
1094 because the tree code is not INTEGER_TYPE.
1095 E.g. for Pascal, when the -fsigned-char option is given. */
1098 fixup_signed_type (type)
1101 register int precision = TYPE_PRECISION (type);
1103 TYPE_MIN_VALUE (type)
1104 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1105 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1106 (((HOST_WIDE_INT) (-1)
1107 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1108 ? precision - HOST_BITS_PER_WIDE_INT - 1
1110 TYPE_MAX_VALUE (type)
1111 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1112 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1113 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1114 ? (((HOST_WIDE_INT) 1
1115 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1118 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1119 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1121 /* Lay out the type: set its alignment, size, etc. */
1126 /* Set the extreme values of TYPE based on its precision in bits,
1127 then lay it out. This is used both in `make_unsigned_type'
1128 and for enumeral types. */
1131 fixup_unsigned_type (type)
1134 register int precision = TYPE_PRECISION (type);
1136 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1137 TYPE_MAX_VALUE (type)
1138 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1139 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1140 precision - HOST_BITS_PER_WIDE_INT > 0
1141 ? ((unsigned HOST_WIDE_INT) ~0
1142 >> (HOST_BITS_PER_WIDE_INT
1143 - (precision - HOST_BITS_PER_WIDE_INT)))
1145 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1146 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1148 /* Lay out the type: set its alignment, size, etc. */
1153 /* Find the best machine mode to use when referencing a bit field of length
1154 BITSIZE bits starting at BITPOS.
1156 The underlying object is known to be aligned to a boundary of ALIGN bits.
1157 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1158 larger than LARGEST_MODE (usually SImode).
1160 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1161 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1162 mode meeting these conditions.
1164 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1165 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1166 all the conditions. */
1169 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1170 int bitsize, bitpos;
1172 enum machine_mode largest_mode;
1175 enum machine_mode mode;
1178 /* Find the narrowest integer mode that contains the bit field. */
1179 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1180 mode = GET_MODE_WIDER_MODE (mode))
1182 unit = GET_MODE_BITSIZE (mode);
1183 if (bitpos / unit == (bitpos + bitsize - 1) / unit)
1187 if (mode == MAX_MACHINE_MODE
1188 /* It is tempting to omit the following line
1189 if STRICT_ALIGNMENT is true.
1190 But that is incorrect, since if the bitfield uses part of 3 bytes
1191 and we use a 4-byte mode, we could get a spurious segv
1192 if the extra 4th byte is past the end of memory.
1193 (Though at least one Unix compiler ignores this problem:
1194 that on the Sequent 386 machine. */
1195 || MIN (unit, BIGGEST_ALIGNMENT) > align
1196 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1199 if (SLOW_BYTE_ACCESS && ! volatilep)
1201 enum machine_mode wide_mode = VOIDmode, tmode;
1203 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1204 tmode = GET_MODE_WIDER_MODE (tmode))
1206 unit = GET_MODE_BITSIZE (tmode);
1207 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1208 && unit <= BITS_PER_WORD
1209 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1210 && (largest_mode == VOIDmode
1211 || unit <= GET_MODE_BITSIZE (largest_mode)))
1215 if (wide_mode != VOIDmode)
1222 /* Save all variables describing the current status into the structure *P.
1223 This is used before starting a nested function. */
1226 save_storage_status (p)
1229 #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
1230 p->pending_sizes = pending_sizes;
1231 p->immediate_size_expand = immediate_size_expand;
1235 /* Restore all variables describing the current status from the structure *P.
1236 This is used after a nested function. */
1239 restore_storage_status (p)
1243 pending_sizes = p->pending_sizes;
1244 immediate_size_expand = p->immediate_size_expand;