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 #define GET_MODE_ALIGNMENT(MODE) \
55 MIN (BIGGEST_ALIGNMENT, \
56 MAX (1, (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT)))
58 static enum machine_mode smallest_mode_for_size PROTO((unsigned int,
60 static tree layout_record PROTO((tree));
61 static void layout_union PROTO((tree));
63 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
65 static tree pending_sizes;
67 /* Nonzero means cannot safely call expand_expr now,
68 so put variable sizes onto `pending_sizes' instead. */
70 int immediate_size_expand;
75 tree chain = pending_sizes;
78 /* Put each SAVE_EXPR into the current function. */
79 for (t = chain; t; t = TREE_CHAIN (t))
80 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
86 put_pending_sizes (chain)
92 pending_sizes = chain;
95 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
96 to serve as the actual size-expression for a type or decl. */
102 /* If the language-processor is to take responsibility for variable-sized
103 items (e.g., languages which have elaboration procedures like Ada),
104 just return SIZE unchanged. Likewise for self-referential sizes. */
105 if (TREE_CONSTANT (size)
106 || global_bindings_p () < 0 || contains_placeholder_p (size))
109 size = save_expr (size);
111 if (global_bindings_p ())
113 if (TREE_CONSTANT (size))
114 error ("type size can't be explicitly evaluated");
116 error ("variable-size type declared outside of any function");
121 if (immediate_size_expand)
122 /* NULL_RTX is not defined; neither is the rtx type.
123 Also, we would like to pass const0_rtx here, but don't have it. */
124 expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
127 pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
132 #ifndef MAX_FIXED_MODE_SIZE
133 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
136 /* Return the machine mode to use for a nonscalar of SIZE bits.
137 The mode must be in class CLASS, and have exactly that many bits.
138 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
142 mode_for_size (size, class, limit)
144 enum mode_class class;
147 register enum machine_mode mode;
149 if (limit && size > MAX_FIXED_MODE_SIZE)
152 /* Get the first mode which has this size, in the specified class. */
153 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
154 mode = GET_MODE_WIDER_MODE (mode))
155 if (GET_MODE_BITSIZE (mode) == size)
161 /* Similar, but never return BLKmode; return the narrowest mode that
162 contains at least the requested number of bits. */
164 static enum machine_mode
165 smallest_mode_for_size (size, class)
167 enum mode_class class;
169 register enum machine_mode mode;
171 /* Get the first mode which has at least this size, in the
173 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
174 mode = GET_MODE_WIDER_MODE (mode))
175 if (GET_MODE_BITSIZE (mode) >= size)
181 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
184 round_up (value, divisor)
188 return size_binop (MULT_EXPR,
189 size_binop (CEIL_DIV_EXPR, value, size_int (divisor)),
193 /* Set the size, mode and alignment of a ..._DECL node.
194 TYPE_DECL does need this for C++.
195 Note that LABEL_DECL and CONST_DECL nodes do not need this,
196 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
197 Don't call layout_decl for them.
199 KNOWN_ALIGN is the amount of alignment we can assume this
200 decl has with no special effort. It is relevant only for FIELD_DECLs
201 and depends on the previous fields.
202 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
203 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
204 the record will be aligned to suit. */
207 layout_decl (decl, known_align)
209 unsigned known_align;
211 register tree type = TREE_TYPE (decl);
212 register enum tree_code code = TREE_CODE (decl);
213 int spec_size = DECL_FIELD_SIZE (decl);
215 if (code == CONST_DECL)
218 if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
219 && code != FIELD_DECL && code != TYPE_DECL)
222 if (type == error_mark_node)
224 type = void_type_node;
228 /* Usually the size and mode come from the data type without change. */
230 DECL_MODE (decl) = TYPE_MODE (type);
231 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
232 if (DECL_SIZE (decl) == 0)
233 DECL_SIZE (decl) = TYPE_SIZE (type);
235 if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
237 if (spec_size == 0 && DECL_NAME (decl) != 0)
240 /* Size is specified number of bits. */
241 DECL_SIZE (decl) = size_int (spec_size);
243 /* Force alignment required for the data type.
244 But if the decl itself wants greater alignment, don't override that.
245 Likewise, if the decl is packed, don't override it. */
246 else if (DECL_ALIGN (decl) == 0
247 || (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl)))
248 DECL_ALIGN (decl) = TYPE_ALIGN (type);
250 /* See if we can use an ordinary integer mode for a bit-field. */
251 /* Conditions are: a fixed size that is correct for another mode
252 and occupying a complete byte or bytes on proper boundary. */
253 if (code == FIELD_DECL)
255 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
256 if (maximum_field_alignment != 0)
257 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
258 else if (DECL_PACKED (decl))
259 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
262 if (DECL_BIT_FIELD (decl)
263 && TYPE_SIZE (type) != 0
264 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
265 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
267 register enum machine_mode xmode
268 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1);
271 && known_align % GET_MODE_ALIGNMENT (xmode) == 0)
273 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
275 DECL_MODE (decl) = xmode;
276 DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode));
277 /* This no longer needs to be accessed as a bit field. */
278 DECL_BIT_FIELD (decl) = 0;
282 /* Turn off DECL_BIT_FIELD if we won't need it set. */
283 if (DECL_BIT_FIELD (decl) && TYPE_MODE (type) == BLKmode
284 && known_align % TYPE_ALIGN (type) == 0
285 && DECL_SIZE (decl) != 0
286 && (TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST
287 || (TREE_INT_CST_LOW (DECL_SIZE (decl)) % BITS_PER_UNIT) == 0))
288 DECL_BIT_FIELD (decl) = 0;
290 /* Evaluate nonconstant size only once, either now or as soon as safe. */
291 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
292 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
295 /* Lay out a RECORD_TYPE type (a C struct).
296 This means laying out the fields, determining their positions,
297 and computing the overall size and required alignment of the record.
298 Note that if you set the TYPE_ALIGN before calling this
299 then the struct is aligned to at least that boundary.
301 If the type has basetypes, you must call layout_basetypes
302 before calling this function.
304 The return value is a list of static members of the record.
305 They still need to be laid out. */
312 #ifdef STRUCTURE_SIZE_BOUNDARY
313 unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
315 unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
317 /* These must be laid out *after* the record is. */
318 tree pending_statics = NULL_TREE;
319 /* Record size so far is CONST_SIZE + VAR_SIZE bits,
320 where CONST_SIZE is an integer
321 and VAR_SIZE is a tree expression.
322 If VAR_SIZE is null, the size is just CONST_SIZE.
323 Naturally we try to avoid using VAR_SIZE. */
324 register int const_size = 0;
325 register tree var_size = 0;
326 /* Once we start using VAR_SIZE, this is the maximum alignment
327 that we know VAR_SIZE has. */
328 register int var_align = BITS_PER_UNIT;
331 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
333 register int known_align = var_size ? var_align : const_size;
334 register int desired_align;
336 /* If FIELD is static, then treat it like a separate variable,
337 not really like a structure field.
338 If it is a FUNCTION_DECL, it's a method.
339 In both cases, all we do is lay out the decl,
340 and we do it *after* the record is laid out. */
342 if (TREE_STATIC (field))
344 pending_statics = tree_cons (NULL_TREE, field, pending_statics);
347 /* Enumerators and enum types which are local to this class need not
348 be laid out. Likewise for initialized constant fields. */
349 if (TREE_CODE (field) != FIELD_DECL)
352 /* Lay out the field so we know what alignment it needs.
353 For a packed field, use the alignment as specified,
354 disregarding what the type would want. */
355 if (DECL_PACKED (field))
356 desired_align = DECL_ALIGN (field);
357 layout_decl (field, known_align);
358 if (! DECL_PACKED (field))
359 desired_align = DECL_ALIGN (field);
360 /* Some targets (i.e. VMS) limit struct field alignment
361 to a lower boundary than alignment of variables. */
362 #ifdef BIGGEST_FIELD_ALIGNMENT
363 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
365 #ifdef ADJUST_FIELD_ALIGN
366 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
369 /* Record must have at least as much alignment as any field.
370 Otherwise, the alignment of the field within the record
373 #ifndef PCC_BITFIELD_TYPE_MATTERS
374 record_align = MAX (record_align, desired_align);
376 if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
377 && DECL_BIT_FIELD_TYPE (field)
378 && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
380 /* For these machines, a zero-length field does not
381 affect the alignment of the structure as a whole.
382 It does, however, affect the alignment of the next field
383 within the structure. */
384 if (! integer_zerop (DECL_SIZE (field)))
385 record_align = MAX (record_align, desired_align);
386 else if (! DECL_PACKED (field))
387 desired_align = TYPE_ALIGN (TREE_TYPE (field));
388 /* A named bit field of declared type `int'
389 forces the entire structure to have `int' alignment. */
390 if (DECL_NAME (field) != 0)
392 int type_align = TYPE_ALIGN (TREE_TYPE (field));
393 if (maximum_field_alignment != 0)
394 type_align = MIN (type_align, maximum_field_alignment);
395 else if (TYPE_PACKED (rec))
396 type_align = MIN (type_align, BITS_PER_UNIT);
398 record_align = MAX (record_align, type_align);
402 record_align = MAX (record_align, desired_align);
405 /* Does this field automatically have alignment it needs
406 by virtue of the fields that precede it and the record's
409 if (const_size % desired_align != 0
410 || (var_align % desired_align != 0
413 /* No, we need to skip space before this field.
414 Bump the cumulative size to multiple of field alignment. */
417 || var_align % desired_align == 0)
419 = CEIL (const_size, desired_align) * desired_align;
423 var_size = size_binop (PLUS_EXPR, var_size,
424 size_int (const_size));
426 var_size = round_up (var_size, desired_align);
427 var_align = MIN (var_align, desired_align);
431 #ifdef PCC_BITFIELD_TYPE_MATTERS
432 if (PCC_BITFIELD_TYPE_MATTERS
433 && TREE_CODE (field) == FIELD_DECL
434 && TREE_TYPE (field) != error_mark_node
435 && DECL_BIT_FIELD_TYPE (field)
436 && !DECL_PACKED (field)
437 && maximum_field_alignment == 0
438 && !integer_zerop (DECL_SIZE (field)))
440 int type_align = TYPE_ALIGN (TREE_TYPE (field));
441 register tree dsize = DECL_SIZE (field);
442 int field_size = TREE_INT_CST_LOW (dsize);
444 /* A bit field may not span the unit of alignment of its type.
445 Advance to next boundary if necessary. */
446 /* ??? There is some uncertainty here as to what
447 should be done if type_align is less than the width of the type.
448 That can happen because the width exceeds BIGGEST_ALIGNMENT
449 or because it exceeds maximum_field_alignment. */
450 if (const_size / type_align
451 != (const_size + (field_size % type_align) - 1) / type_align)
452 const_size = CEIL (const_size, type_align) * type_align;
456 /* No existing machine description uses this parameter.
457 So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
458 #ifdef BITFIELD_NBYTES_LIMITED
459 if (BITFIELD_NBYTES_LIMITED
460 && TREE_CODE (field) == FIELD_DECL
461 && TREE_TYPE (field) != error_mark_node
462 && DECL_BIT_FIELD_TYPE (field)
463 && !DECL_PACKED (field)
464 && !integer_zerop (DECL_SIZE (field)))
466 int type_align = TYPE_ALIGN (TREE_TYPE (field));
467 register tree dsize = DECL_SIZE (field);
468 int field_size = TREE_INT_CST_LOW (dsize);
470 if (maximum_field_alignment != 0)
471 type_align = MIN (type_align, maximum_field_alignment);
472 else if (TYPE_PACKED (rec))
473 type_align = MIN (type_align, BITS_PER_UNIT);
475 /* A bit field may not span the unit of alignment of its type.
476 Advance to next boundary if necessary. */
477 if (const_size / type_align
478 != (const_size + field_size - 1) / type_align)
479 const_size = CEIL (const_size, type_align) * type_align;
483 /* Size so far becomes the position of this field. */
485 if (var_size && const_size)
486 DECL_FIELD_BITPOS (field)
487 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
489 DECL_FIELD_BITPOS (field) = var_size;
492 DECL_FIELD_BITPOS (field) = size_int (const_size);
494 /* If this field ended up more aligned than we thought it
495 would be (we approximate this by seeing if its position
496 changed), lay out the field again; perhaps we can use an
497 integral mode for it now. */
498 if (known_align != const_size)
499 layout_decl (field, const_size);
502 /* Now add size of this field to the size of the record. */
505 register tree dsize = DECL_SIZE (field);
507 /* This can happen when we have an invalid nested struct definition,
508 such as struct j { struct j { int i; } }. The error message is
509 printed in finish_struct. */
512 else if (TREE_CODE (dsize) == INTEGER_CST
513 && TREE_INT_CST_HIGH (dsize) == 0
514 && TREE_INT_CST_LOW (dsize) + const_size > const_size)
515 /* Use const_size if there's no overflow. */
516 const_size += TREE_INT_CST_LOW (dsize);
522 var_size = size_binop (PLUS_EXPR, var_size, dsize);
527 /* Work out the total size and alignment of the record
528 as one expression and store in the record type.
529 Round it up to a multiple of the record's alignment. */
533 TYPE_SIZE (rec) = size_int (const_size);
539 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
540 TYPE_SIZE (rec) = var_size;
543 /* Determine the desired alignment. */
544 #ifdef ROUND_TYPE_ALIGN
545 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
547 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
550 #ifdef ROUND_TYPE_SIZE
551 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
553 /* Round the size up to be a multiple of the required alignment */
554 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
557 return pending_statics;
560 /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
561 Lay out all the fields, set their positions to zero,
562 and compute the size and alignment of the union (maximum of any field).
563 Note that if you set the TYPE_ALIGN before calling this
564 then the union align is aligned to at least that boundary. */
571 #ifdef STRUCTURE_SIZE_BOUNDARY
572 unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
574 unsigned union_align = BITS_PER_UNIT;
577 /* The size of the union, based on the fields scanned so far,
578 is max (CONST_SIZE, VAR_SIZE).
579 VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
580 register int const_size = 0;
581 register tree var_size = 0;
583 /* If this is a QUAL_UNION_TYPE, we want to process the fields in
584 the reverse order in building the COND_EXPR that denotes its
585 size. We reverse them again later. */
586 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
587 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
589 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
591 /* Enums which are local to this class need not be laid out. */
592 if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
595 layout_decl (field, 0);
596 DECL_FIELD_BITPOS (field) = size_int (0);
598 /* Union must be at least as aligned as any field requires. */
600 union_align = MAX (union_align, DECL_ALIGN (field));
602 #ifdef PCC_BITFIELD_TYPE_MATTERS
603 /* On the m88000, a bit field of declare type `int'
604 forces the entire union to have `int' alignment. */
605 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
606 union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
609 if (TREE_CODE (rec) == UNION_TYPE)
611 /* Set union_size to max (decl_size, union_size).
612 There are more and less general ways to do this.
613 Use only CONST_SIZE unless forced to use VAR_SIZE. */
615 if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
617 = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
618 else if (var_size == 0)
619 var_size = DECL_SIZE (field);
621 var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
623 else if (TREE_CODE (rec) == QUAL_UNION_TYPE)
624 var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field),
626 var_size ? var_size : integer_zero_node));
629 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
630 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
632 /* Determine the ultimate size of the union (in bytes). */
633 if (NULL == var_size)
634 TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
636 else if (const_size == 0)
637 TYPE_SIZE (rec) = var_size;
639 TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
640 round_up (size_int (const_size),
643 /* Determine the desired alignment. */
644 #ifdef ROUND_TYPE_ALIGN
645 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
647 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
650 #ifdef ROUND_TYPE_SIZE
651 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
653 /* Round the size up to be a multiple of the required alignment */
654 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
658 /* Calculate the mode, size, and alignment for TYPE.
659 For an array type, calculate the element separation as well.
660 Record TYPE on the chain of permanent or temporary types
661 so that dbxout will find out about it.
663 TYPE_SIZE of a type is nonzero if the type has been laid out already.
664 layout_type does nothing on such a type.
666 If the type is incomplete, its TYPE_SIZE remains zero. */
673 tree pending_statics;
678 /* Do nothing if type has been laid out before. */
679 if (TYPE_SIZE (type))
682 /* Make sure all nodes we allocate are not momentary;
683 they must last past the current statement. */
684 old = suspend_momentary ();
686 /* Put all our nodes into the same obstack as the type. Also,
687 make expressions saveable (this is a no-op for permanent types). */
689 push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type));
690 saveable_allocation ();
692 switch (TREE_CODE (type))
695 /* This kind of type is the responsibility
696 of the language-specific code. */
702 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
703 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
704 TREE_UNSIGNED (type) = 1;
706 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
708 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
712 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
713 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
717 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
719 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
720 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
721 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
723 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
727 TYPE_SIZE (type) = size_zero_node;
728 TYPE_ALIGN (type) = 1;
729 TYPE_MODE (type) = VOIDmode;
733 TYPE_SIZE (type) = size_int (POINTER_SIZE);
734 TYPE_MODE (type) = ptr_mode;
739 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
740 TYPE_SIZE (type) = size_int (2 * POINTER_SIZE);
745 TYPE_MODE (type) = ptr_mode;
746 TYPE_SIZE (type) = size_int (POINTER_SIZE);
747 TREE_UNSIGNED (type) = 1;
748 TYPE_PRECISION (type) = POINTER_SIZE;
753 register tree index = TYPE_DOMAIN (type);
754 register tree element = TREE_TYPE (type);
756 build_pointer_type (element);
758 /* We need to know both bounds in order to compute the size. */
759 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
760 && TYPE_SIZE (element))
762 tree ub = TYPE_MAX_VALUE (index);
763 tree lb = TYPE_MIN_VALUE (index);
766 /* If UB is max (lb - 1, x), remove the MAX_EXPR since the
767 test for negative below covers it. */
768 if (TREE_CODE (ub) == MAX_EXPR
769 && TREE_CODE (TREE_OPERAND (ub, 0)) == MINUS_EXPR
770 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 0), 1))
771 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 0), 0),
773 ub = TREE_OPERAND (ub, 1);
774 else if (TREE_CODE (ub) == MAX_EXPR
775 && TREE_CODE (TREE_OPERAND (ub, 1)) == MINUS_EXPR
776 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 1), 1))
777 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 1),
780 ub = TREE_OPERAND (ub, 0);
782 length = size_binop (PLUS_EXPR, size_one_node,
783 size_binop (MINUS_EXPR, ub, lb));
785 /* If neither bound is a constant and sizetype is signed, make
786 sure the size is never negative. We should really do this
787 if *either* bound is non-constant, but this is the best
788 compromise between C and Ada. */
789 if (! TREE_UNSIGNED (sizetype)
790 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
791 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
792 length = size_binop (MAX_EXPR, length, size_zero_node);
794 TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
795 TYPE_SIZE (element));
798 /* Now round the alignment and size,
799 using machine-dependent criteria if any. */
801 #ifdef ROUND_TYPE_ALIGN
803 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
805 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
808 #ifdef ROUND_TYPE_SIZE
809 if (TYPE_SIZE (type) != 0)
811 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
814 TYPE_MODE (type) = BLKmode;
815 if (TYPE_SIZE (type) != 0
816 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
817 /* BLKmode elements force BLKmode aggregate;
818 else extract/store fields may lose. */
819 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
820 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
823 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
826 if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
827 && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
828 && TYPE_MODE (type) != BLKmode)
830 TYPE_NO_FORCE_BLK (type) = 1;
831 TYPE_MODE (type) = BLKmode;
838 pending_statics = layout_record (type);
839 TYPE_MODE (type) = BLKmode;
840 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
843 /* A record which has any BLKmode members must itself be BLKmode;
844 it can't go in a register.
845 Unless the member is BLKmode only because it isn't aligned. */
846 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
850 if (TREE_CODE (field) != FIELD_DECL)
853 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
854 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
857 if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
860 bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
862 /* Must be BLKmode if any field crosses a word boundary,
863 since extract_bit_field can't handle that in registers. */
864 if (bitpos / BITS_PER_WORD
865 != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
867 /* But there is no problem if the field is entire words. */
868 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
873 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
876 /* If structure's known alignment is less than
877 what the scalar mode would need, and it matters,
878 then stick with BLKmode. */
880 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
881 || (TYPE_ALIGN (type)
882 >= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
884 if (TYPE_MODE (type) != BLKmode)
885 /* If this is the only reason this type is BLKmode,
886 then don't force containing types to be BLKmode. */
887 TYPE_NO_FORCE_BLK (type) = 1;
888 TYPE_MODE (type) = BLKmode;
894 /* Lay out any static members. This is done now
895 because their type may use the record's type. */
896 while (pending_statics)
898 layout_decl (TREE_VALUE (pending_statics), 0);
899 pending_statics = TREE_CHAIN (pending_statics);
904 case QUAL_UNION_TYPE:
906 TYPE_MODE (type) = BLKmode;
907 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
908 /* If structure's known alignment is less than
909 what the scalar mode would need, and it matters,
910 then stick with BLKmode. */
911 && (! STRICT_ALIGNMENT
912 || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
913 || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
916 /* A union which has any BLKmode members must itself be BLKmode;
917 it can't go in a register.
918 Unless the member is BLKmode only because it isn't aligned. */
919 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
921 if (TREE_CODE (field) != FIELD_DECL)
924 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
925 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
930 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
937 /* Pascal and Chill types */
938 case BOOLEAN_TYPE: /* store one byte/boolean for now. */
939 TYPE_MODE (type) = QImode;
940 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
941 TYPE_PRECISION (type) = 1;
942 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
943 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
944 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
945 TREE_UNSIGNED (type) = 1;
949 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
950 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
954 #ifndef SET_WORD_SIZE
955 #define SET_WORD_SIZE BITS_PER_WORD
957 int alignment = set_alignment ? set_alignment : SET_WORD_SIZE;
959 TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
960 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1;
962 = ((size_in_bits + alignment - 1) / alignment) * alignment;
963 if (rounded_size > alignment)
964 TYPE_MODE (type) = BLKmode;
966 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
967 TYPE_SIZE (type) = size_int (rounded_size);
968 TYPE_ALIGN (type) = alignment;
969 TYPE_PRECISION (type) = size_in_bits;
974 /* The size may vary in different languages, so the language front end
975 should fill in the size. */
976 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
977 TYPE_MODE (type) = BLKmode;
984 /* Normally, use the alignment corresponding to the mode chosen.
985 However, where strict alignment is not required, avoid
986 over-aligning structures, since most compilers do not do this
989 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
991 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
992 && TREE_CODE (type) != QUAL_UNION_TYPE
993 && TREE_CODE (type) != ARRAY_TYPE)))
994 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
996 /* Evaluate nonconstant size only once, either now or as soon as safe. */
997 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
998 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1000 /* Also layout any other variants of the type. */
1001 if (TYPE_NEXT_VARIANT (type)
1002 || type != TYPE_MAIN_VARIANT (type))
1005 /* Record layout info of this variant. */
1006 tree size = TYPE_SIZE (type);
1007 int align = TYPE_ALIGN (type);
1008 enum machine_mode mode = TYPE_MODE (type);
1010 /* Copy it into all variants. */
1011 for (variant = TYPE_MAIN_VARIANT (type);
1013 variant = TYPE_NEXT_VARIANT (variant))
1015 TYPE_SIZE (variant) = size;
1016 TYPE_ALIGN (variant) = align;
1017 TYPE_MODE (variant) = mode;
1022 resume_momentary (old);
1025 /* Create and return a type for signed integers of PRECISION bits. */
1028 make_signed_type (precision)
1031 register tree type = make_node (INTEGER_TYPE);
1033 TYPE_PRECISION (type) = precision;
1035 /* Create the extreme values based on the number of bits. */
1037 TYPE_MIN_VALUE (type)
1038 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1039 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1040 (((HOST_WIDE_INT) (-1)
1041 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1042 ? precision - HOST_BITS_PER_WIDE_INT - 1
1044 TYPE_MAX_VALUE (type)
1045 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1046 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1047 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1048 ? (((HOST_WIDE_INT) 1
1049 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1052 /* Give this type's extreme values this type as their type. */
1054 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1055 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1057 /* The first type made with this or `make_unsigned_type'
1058 is the type for size values. */
1065 /* Lay out the type: set its alignment, size, etc. */
1072 /* Create and return a type for unsigned integers of PRECISION bits. */
1075 make_unsigned_type (precision)
1078 register tree type = make_node (INTEGER_TYPE);
1080 TYPE_PRECISION (type) = precision;
1082 /* The first type made with this or `make_signed_type'
1083 is the type for size values. */
1090 fixup_unsigned_type (type);
1094 /* Set the extreme values of TYPE based on its precision in bits,
1095 then lay it out. Used when make_signed_type won't do
1096 because the tree code is not INTEGER_TYPE.
1097 E.g. for Pascal, when the -fsigned-char option is given. */
1100 fixup_signed_type (type)
1103 register int precision = TYPE_PRECISION (type);
1105 TYPE_MIN_VALUE (type)
1106 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1107 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1108 (((HOST_WIDE_INT) (-1)
1109 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1110 ? precision - HOST_BITS_PER_WIDE_INT - 1
1112 TYPE_MAX_VALUE (type)
1113 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1114 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1115 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1116 ? (((HOST_WIDE_INT) 1
1117 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1120 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1121 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1123 /* Lay out the type: set its alignment, size, etc. */
1128 /* Set the extreme values of TYPE based on its precision in bits,
1129 then lay it out. This is used both in `make_unsigned_type'
1130 and for enumeral types. */
1133 fixup_unsigned_type (type)
1136 register int precision = TYPE_PRECISION (type);
1138 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1139 TYPE_MAX_VALUE (type)
1140 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1141 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1142 precision - HOST_BITS_PER_WIDE_INT > 0
1143 ? ((unsigned HOST_WIDE_INT) ~0
1144 >> (HOST_BITS_PER_WIDE_INT
1145 - (precision - HOST_BITS_PER_WIDE_INT)))
1147 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1148 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1150 /* Lay out the type: set its alignment, size, etc. */
1155 /* Find the best machine mode to use when referencing a bit field of length
1156 BITSIZE bits starting at BITPOS.
1158 The underlying object is known to be aligned to a boundary of ALIGN bits.
1159 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1160 larger than LARGEST_MODE (usually SImode).
1162 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1163 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1164 mode meeting these conditions.
1166 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1167 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1168 all the conditions. */
1171 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1172 int bitsize, bitpos;
1174 enum machine_mode largest_mode;
1177 enum machine_mode mode;
1180 /* Find the narrowest integer mode that contains the bit field. */
1181 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1182 mode = GET_MODE_WIDER_MODE (mode))
1184 unit = GET_MODE_BITSIZE (mode);
1185 if (bitpos / unit == (bitpos + bitsize - 1) / unit)
1189 if (mode == MAX_MACHINE_MODE
1190 /* It is tempting to omit the following line
1191 if STRICT_ALIGNMENT is true.
1192 But that is incorrect, since if the bitfield uses part of 3 bytes
1193 and we use a 4-byte mode, we could get a spurious segv
1194 if the extra 4th byte is past the end of memory.
1195 (Though at least one Unix compiler ignores this problem:
1196 that on the Sequent 386 machine. */
1197 || MIN (unit, BIGGEST_ALIGNMENT) > align
1198 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1201 if (SLOW_BYTE_ACCESS && ! volatilep)
1203 enum machine_mode wide_mode = VOIDmode, tmode;
1205 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1206 tmode = GET_MODE_WIDER_MODE (tmode))
1208 unit = GET_MODE_BITSIZE (tmode);
1209 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1210 && unit <= BITS_PER_WORD
1211 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1212 && (largest_mode == VOIDmode
1213 || unit <= GET_MODE_BITSIZE (largest_mode)))
1217 if (wide_mode != VOIDmode)
1224 /* Save all variables describing the current status into the structure *P.
1225 This is used before starting a nested function. */
1228 save_storage_status (p)
1231 #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
1232 p->pending_sizes = pending_sizes;
1233 p->immediate_size_expand = immediate_size_expand;
1237 /* Restore all variables describing the current status from the structure *P.
1238 This is used after a nested function. */
1241 restore_storage_status (p)
1245 pending_sizes = p->pending_sizes;
1246 immediate_size_expand = p->immediate_size_expand;