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. */
29 #define CEIL(x,y) (((x) + (y) - 1) / (y))
31 /* Data type for the expressions representing sizes of data types.
32 It is the first integer type laid out.
37 /* An integer constant with value 0 whose type is sizetype. */
41 /* An integer constant with value 1 whose type is sizetype. */
45 /* If nonzero, this is an upper limit on alignment of structure fields.
46 The value is measured in bits. */
47 int maximum_field_alignment;
49 /* If non-zero, the alignment of a bitstring or (power-)set value, in bits.
50 May be overridden by front-ends. */
51 int set_alignment = 0;
53 #define GET_MODE_ALIGNMENT(MODE) \
54 MIN (BIGGEST_ALIGNMENT, \
55 MAX (1, (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT)))
57 static enum machine_mode smallest_mode_for_size PROTO((unsigned int,
59 static tree layout_record PROTO((tree));
60 static void layout_union PROTO((tree));
62 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
64 static tree pending_sizes;
66 /* Nonzero means cannot safely call expand_expr now,
67 so put variable sizes onto `pending_sizes' instead. */
69 int immediate_size_expand;
74 tree chain = pending_sizes;
77 /* Put each SAVE_EXPR into the current function. */
78 for (t = chain; t; t = TREE_CHAIN (t))
79 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
85 put_pending_sizes (chain)
91 pending_sizes = chain;
94 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
95 to serve as the actual size-expression for a type or decl. */
101 /* If the language-processor is to take responsibility for variable-sized
102 items (e.g., languages which have elaboration procedures like Ada),
103 just return SIZE unchanged. Likewise for self-referential sizes. */
104 if (TREE_CONSTANT (size)
105 || global_bindings_p () < 0 || contains_placeholder_p (size))
108 size = save_expr (size);
110 if (global_bindings_p ())
112 if (TREE_CONSTANT (size))
113 error ("type size can't be explicitly evaluated");
115 error ("variable-size type declared outside of any function");
120 if (immediate_size_expand)
121 /* NULL_RTX is not defined; neither is the rtx type.
122 Also, we would like to pass const0_rtx here, but don't have it. */
123 expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
126 pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
131 #ifndef MAX_FIXED_MODE_SIZE
132 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
135 /* Return the machine mode to use for a nonscalar of SIZE bits.
136 The mode must be in class CLASS, and have exactly that many bits.
137 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
141 mode_for_size (size, class, limit)
143 enum mode_class class;
146 register enum machine_mode mode;
148 if (limit && size > MAX_FIXED_MODE_SIZE)
151 /* Get the first mode which has this size, in the specified class. */
152 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
153 mode = GET_MODE_WIDER_MODE (mode))
154 if (GET_MODE_BITSIZE (mode) == size)
160 /* Similar, but never return BLKmode; return the narrowest mode that
161 contains at least the requested number of bits. */
163 static enum machine_mode
164 smallest_mode_for_size (size, class)
166 enum mode_class class;
168 register enum machine_mode mode;
170 /* Get the first mode which has at least this size, in the
172 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
173 mode = GET_MODE_WIDER_MODE (mode))
174 if (GET_MODE_BITSIZE (mode) >= size)
180 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
183 round_up (value, divisor)
187 return size_binop (MULT_EXPR,
188 size_binop (CEIL_DIV_EXPR, value, size_int (divisor)),
192 /* Set the size, mode and alignment of a ..._DECL node.
193 TYPE_DECL does need this for C++.
194 Note that LABEL_DECL and CONST_DECL nodes do not need this,
195 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
196 Don't call layout_decl for them.
198 KNOWN_ALIGN is the amount of alignment we can assume this
199 decl has with no special effort. It is relevant only for FIELD_DECLs
200 and depends on the previous fields.
201 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
202 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
203 the record will be aligned to suit. */
206 layout_decl (decl, known_align)
208 unsigned known_align;
210 register tree type = TREE_TYPE (decl);
211 register enum tree_code code = TREE_CODE (decl);
212 int spec_size = DECL_FIELD_SIZE (decl);
214 if (code == CONST_DECL)
217 if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
218 && code != FIELD_DECL && code != TYPE_DECL)
221 if (type == error_mark_node)
223 type = void_type_node;
227 /* Usually the size and mode come from the data type without change. */
229 DECL_MODE (decl) = TYPE_MODE (type);
230 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
231 if (DECL_SIZE (decl) == 0)
232 DECL_SIZE (decl) = TYPE_SIZE (type);
234 if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
236 if (spec_size == 0 && DECL_NAME (decl) != 0)
239 /* Size is specified number of bits. */
240 DECL_SIZE (decl) = size_int (spec_size);
242 /* Force alignment required for the data type.
243 But if the decl itself wants greater alignment, don't override that.
244 Likewise, if the decl is packed, don't override it. */
245 else if (DECL_ALIGN (decl) == 0
246 || (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl)))
247 DECL_ALIGN (decl) = TYPE_ALIGN (type);
249 /* See if we can use an ordinary integer mode for a bit-field. */
250 /* Conditions are: a fixed size that is correct for another mode
251 and occupying a complete byte or bytes on proper boundary. */
252 if (code == FIELD_DECL)
254 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
255 if (maximum_field_alignment != 0)
256 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
257 else if (DECL_PACKED (decl))
258 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
261 if (DECL_BIT_FIELD (decl)
262 && TYPE_SIZE (type) != 0
263 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
264 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
266 register enum machine_mode xmode
267 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1);
270 && known_align % GET_MODE_ALIGNMENT (xmode) == 0)
272 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
274 DECL_MODE (decl) = xmode;
275 DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode));
276 /* This no longer needs to be accessed as a bit field. */
277 DECL_BIT_FIELD (decl) = 0;
281 /* Turn off DECL_BIT_FIELD if we won't need it set. */
282 if (DECL_BIT_FIELD (decl) && TYPE_MODE (type) == BLKmode
283 && known_align % TYPE_ALIGN (type) == 0
284 && DECL_SIZE (decl) != 0
285 && (TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST
286 || (TREE_INT_CST_LOW (DECL_SIZE (decl)) % BITS_PER_UNIT) == 0))
287 DECL_BIT_FIELD (decl) = 0;
289 /* Evaluate nonconstant size only once, either now or as soon as safe. */
290 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
291 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
294 /* Lay out a RECORD_TYPE type (a C struct).
295 This means laying out the fields, determining their positions,
296 and computing the overall size and required alignment of the record.
297 Note that if you set the TYPE_ALIGN before calling this
298 then the struct is aligned to at least that boundary.
300 If the type has basetypes, you must call layout_basetypes
301 before calling this function.
303 The return value is a list of static members of the record.
304 They still need to be laid out. */
311 #ifdef STRUCTURE_SIZE_BOUNDARY
312 unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
314 unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
316 /* These must be laid out *after* the record is. */
317 tree pending_statics = NULL_TREE;
318 /* Record size so far is CONST_SIZE + VAR_SIZE bits,
319 where CONST_SIZE is an integer
320 and VAR_SIZE is a tree expression.
321 If VAR_SIZE is null, the size is just CONST_SIZE.
322 Naturally we try to avoid using VAR_SIZE. */
323 register int const_size = 0;
324 register tree var_size = 0;
325 /* Once we start using VAR_SIZE, this is the maximum alignment
326 that we know VAR_SIZE has. */
327 register int var_align = BITS_PER_UNIT;
330 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
332 register int known_align = var_size ? var_align : const_size;
333 register int desired_align;
335 /* If FIELD is static, then treat it like a separate variable,
336 not really like a structure field.
337 If it is a FUNCTION_DECL, it's a method.
338 In both cases, all we do is lay out the decl,
339 and we do it *after* the record is laid out. */
341 if (TREE_STATIC (field))
343 pending_statics = tree_cons (NULL_TREE, field, pending_statics);
346 /* Enumerators and enum types which are local to this class need not
347 be laid out. Likewise for initialized constant fields. */
348 if (TREE_CODE (field) != FIELD_DECL)
351 /* Lay out the field so we know what alignment it needs.
352 For a packed field, use the alignment as specified,
353 disregarding what the type would want. */
354 if (DECL_PACKED (field))
355 desired_align = DECL_ALIGN (field);
356 layout_decl (field, known_align);
357 if (! DECL_PACKED (field))
358 desired_align = DECL_ALIGN (field);
359 /* Some targets (i.e. VMS) limit struct field alignment
360 to a lower boundary than alignment of variables. */
361 #ifdef BIGGEST_FIELD_ALIGNMENT
362 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
364 #ifdef ADJUST_FIELD_ALIGN
365 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
368 /* Record must have at least as much alignment as any field.
369 Otherwise, the alignment of the field within the record
372 #ifndef PCC_BITFIELD_TYPE_MATTERS
373 record_align = MAX (record_align, desired_align);
375 if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
376 && DECL_BIT_FIELD_TYPE (field)
377 && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
379 /* For these machines, a zero-length field does not
380 affect the alignment of the structure as a whole.
381 It does, however, affect the alignment of the next field
382 within the structure. */
383 if (! integer_zerop (DECL_SIZE (field)))
384 record_align = MAX (record_align, desired_align);
385 else if (! DECL_PACKED (field))
386 desired_align = TYPE_ALIGN (TREE_TYPE (field));
387 /* A named bit field of declared type `int'
388 forces the entire structure to have `int' alignment. */
389 if (DECL_NAME (field) != 0)
391 int type_align = TYPE_ALIGN (TREE_TYPE (field));
392 if (maximum_field_alignment != 0)
393 type_align = MIN (type_align, maximum_field_alignment);
394 else if (TYPE_PACKED (rec))
395 type_align = MIN (type_align, BITS_PER_UNIT);
397 record_align = MAX (record_align, type_align);
401 record_align = MAX (record_align, desired_align);
404 /* Does this field automatically have alignment it needs
405 by virtue of the fields that precede it and the record's
408 if (const_size % desired_align != 0
409 || (var_align % desired_align != 0
412 /* No, we need to skip space before this field.
413 Bump the cumulative size to multiple of field alignment. */
416 || var_align % desired_align == 0)
418 = CEIL (const_size, desired_align) * desired_align;
422 var_size = size_binop (PLUS_EXPR, var_size,
423 size_int (const_size));
425 var_size = round_up (var_size, desired_align);
426 var_align = MIN (var_align, desired_align);
430 #ifdef PCC_BITFIELD_TYPE_MATTERS
431 if (PCC_BITFIELD_TYPE_MATTERS
432 && TREE_CODE (field) == FIELD_DECL
433 && TREE_TYPE (field) != error_mark_node
434 && DECL_BIT_FIELD_TYPE (field)
435 && !DECL_PACKED (field)
436 && maximum_field_alignment == 0
437 && !integer_zerop (DECL_SIZE (field)))
439 int type_align = TYPE_ALIGN (TREE_TYPE (field));
440 register tree dsize = DECL_SIZE (field);
441 int field_size = TREE_INT_CST_LOW (dsize);
443 /* A bit field may not span the unit of alignment of its type.
444 Advance to next boundary if necessary. */
445 /* ??? There is some uncertainty here as to what
446 should be done if type_align is less than the width of the type.
447 That can happen because the width exceeds BIGGEST_ALIGNMENT
448 or because it exceeds maximum_field_alignment. */
449 if (const_size / type_align
450 != (const_size + (field_size % type_align) - 1) / type_align)
451 const_size = CEIL (const_size, type_align) * type_align;
455 /* No existing machine description uses this parameter.
456 So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
457 #ifdef BITFIELD_NBYTES_LIMITED
458 if (BITFIELD_NBYTES_LIMITED
459 && TREE_CODE (field) == FIELD_DECL
460 && TREE_TYPE (field) != error_mark_node
461 && DECL_BIT_FIELD_TYPE (field)
462 && !DECL_PACKED (field)
463 && !integer_zerop (DECL_SIZE (field)))
465 int type_align = TYPE_ALIGN (TREE_TYPE (field));
466 register tree dsize = DECL_SIZE (field);
467 int field_size = TREE_INT_CST_LOW (dsize);
469 if (maximum_field_alignment != 0)
470 type_align = MIN (type_align, maximum_field_alignment);
471 else if (TYPE_PACKED (rec))
472 type_align = MIN (type_align, BITS_PER_UNIT);
474 /* A bit field may not span the unit of alignment of its type.
475 Advance to next boundary if necessary. */
476 if (const_size / type_align
477 != (const_size + field_size - 1) / type_align)
478 const_size = CEIL (const_size, type_align) * type_align;
482 /* Size so far becomes the position of this field. */
484 if (var_size && const_size)
485 DECL_FIELD_BITPOS (field)
486 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
488 DECL_FIELD_BITPOS (field) = var_size;
491 DECL_FIELD_BITPOS (field) = size_int (const_size);
493 /* If this field ended up more aligned than we thought it
494 would be (we approximate this by seeing if its position
495 changed), lay out the field again; perhaps we can use an
496 integral mode for it now. */
497 if (known_align != const_size)
498 layout_decl (field, const_size);
501 /* Now add size of this field to the size of the record. */
504 register tree dsize = DECL_SIZE (field);
506 /* This can happen when we have an invalid nested struct definition,
507 such as struct j { struct j { int i; } }. The error message is
508 printed in finish_struct. */
511 else if (TREE_CODE (dsize) == INTEGER_CST
512 && TREE_INT_CST_HIGH (dsize) == 0
513 && TREE_INT_CST_LOW (dsize) + const_size > const_size)
514 /* Use const_size if there's no overflow. */
515 const_size += TREE_INT_CST_LOW (dsize);
521 var_size = size_binop (PLUS_EXPR, var_size, dsize);
526 /* Work out the total size and alignment of the record
527 as one expression and store in the record type.
528 Round it up to a multiple of the record's alignment. */
532 TYPE_SIZE (rec) = size_int (const_size);
538 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
539 TYPE_SIZE (rec) = var_size;
542 /* Determine the desired alignment. */
543 #ifdef ROUND_TYPE_ALIGN
544 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
546 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
549 #ifdef ROUND_TYPE_SIZE
550 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
552 /* Round the size up to be a multiple of the required alignment */
553 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
556 return pending_statics;
559 /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
560 Lay out all the fields, set their positions to zero,
561 and compute the size and alignment of the union (maximum of any field).
562 Note that if you set the TYPE_ALIGN before calling this
563 then the union align is aligned to at least that boundary. */
570 #ifdef STRUCTURE_SIZE_BOUNDARY
571 unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
573 unsigned union_align = BITS_PER_UNIT;
576 /* The size of the union, based on the fields scanned so far,
577 is max (CONST_SIZE, VAR_SIZE).
578 VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
579 register int const_size = 0;
580 register tree var_size = 0;
582 /* If this is a QUAL_UNION_TYPE, we want to process the fields in
583 the reverse order in building the COND_EXPR that denotes its
584 size. We reverse them again later. */
585 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
586 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
588 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
590 /* Enums which are local to this class need not be laid out. */
591 if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
594 layout_decl (field, 0);
595 DECL_FIELD_BITPOS (field) = size_int (0);
597 /* Union must be at least as aligned as any field requires. */
599 union_align = MAX (union_align, DECL_ALIGN (field));
601 #ifdef PCC_BITFIELD_TYPE_MATTERS
602 /* On the m88000, a bit field of declare type `int'
603 forces the entire union to have `int' alignment. */
604 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
605 union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
608 if (TREE_CODE (rec) == UNION_TYPE)
610 /* Set union_size to max (decl_size, union_size).
611 There are more and less general ways to do this.
612 Use only CONST_SIZE unless forced to use VAR_SIZE. */
614 if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
616 = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
617 else if (var_size == 0)
618 var_size = DECL_SIZE (field);
620 var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
622 else if (TREE_CODE (rec) == QUAL_UNION_TYPE)
623 var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field),
625 var_size ? var_size : integer_zero_node));
628 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
629 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
631 /* Determine the ultimate size of the union (in bytes). */
632 if (NULL == var_size)
633 TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
635 else if (const_size == 0)
636 TYPE_SIZE (rec) = var_size;
638 TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
639 round_up (size_int (const_size),
642 /* Determine the desired alignment. */
643 #ifdef ROUND_TYPE_ALIGN
644 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
646 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
649 #ifdef ROUND_TYPE_SIZE
650 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
652 /* Round the size up to be a multiple of the required alignment */
653 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
657 /* Calculate the mode, size, and alignment for TYPE.
658 For an array type, calculate the element separation as well.
659 Record TYPE on the chain of permanent or temporary types
660 so that dbxout will find out about it.
662 TYPE_SIZE of a type is nonzero if the type has been laid out already.
663 layout_type does nothing on such a type.
665 If the type is incomplete, its TYPE_SIZE remains zero. */
672 tree pending_statics;
677 /* Do nothing if type has been laid out before. */
678 if (TYPE_SIZE (type))
681 /* Make sure all nodes we allocate are not momentary;
682 they must last past the current statement. */
683 old = suspend_momentary ();
685 /* Put all our nodes into the same obstack as the type. Also,
686 make expressions saveable (this is a no-op for permanent types). */
688 push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type));
689 saveable_allocation ();
691 switch (TREE_CODE (type))
694 /* This kind of type is the responsibility
695 of the language-specific code. */
701 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
702 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
703 TREE_UNSIGNED (type) = 1;
705 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
707 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
711 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
712 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
716 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
718 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
719 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
720 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
722 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
726 TYPE_SIZE (type) = size_zero_node;
727 TYPE_ALIGN (type) = 1;
728 TYPE_MODE (type) = VOIDmode;
732 TYPE_SIZE (type) = size_int (POINTER_SIZE);
733 TYPE_MODE (type) = ptr_mode;
738 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
739 TYPE_SIZE (type) = size_int (2 * POINTER_SIZE);
744 TYPE_MODE (type) = ptr_mode;
745 TYPE_SIZE (type) = size_int (POINTER_SIZE);
746 TREE_UNSIGNED (type) = 1;
747 TYPE_PRECISION (type) = POINTER_SIZE;
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))
761 tree ub = TYPE_MAX_VALUE (index);
762 tree lb = TYPE_MIN_VALUE (index);
765 /* If UB is max (lb - 1, x), remove the MAX_EXPR since the
766 test for negative below covers it. */
767 if (TREE_CODE (ub) == MAX_EXPR
768 && TREE_CODE (TREE_OPERAND (ub, 0)) == MINUS_EXPR
769 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 0), 1))
770 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 0), 0),
772 ub = TREE_OPERAND (ub, 1);
773 else if (TREE_CODE (ub) == MAX_EXPR
774 && TREE_CODE (TREE_OPERAND (ub, 1)) == MINUS_EXPR
775 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 1), 1))
776 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 1),
779 ub = TREE_OPERAND (ub, 0);
781 length = size_binop (PLUS_EXPR, size_one_node,
782 size_binop (MINUS_EXPR, ub, lb));
784 /* If neither bound is a constant and sizetype is signed, make
785 sure the size is never negative. We should really do this
786 if *either* bound is non-constant, but this is the best
787 compromise between C and Ada. */
788 if (! TREE_UNSIGNED (sizetype)
789 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
790 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
791 length = size_binop (MAX_EXPR, length, size_zero_node);
793 TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
794 TYPE_SIZE (element));
797 /* Now round the alignment and size,
798 using machine-dependent criteria if any. */
800 #ifdef ROUND_TYPE_ALIGN
802 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
804 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
807 #ifdef ROUND_TYPE_SIZE
808 if (TYPE_SIZE (type) != 0)
810 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
813 TYPE_MODE (type) = BLKmode;
814 if (TYPE_SIZE (type) != 0
815 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
816 /* BLKmode elements force BLKmode aggregate;
817 else extract/store fields may lose. */
818 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
819 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
822 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
825 if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
826 && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
827 && TYPE_MODE (type) != BLKmode)
829 TYPE_NO_FORCE_BLK (type) = 1;
830 TYPE_MODE (type) = BLKmode;
837 pending_statics = layout_record (type);
838 TYPE_MODE (type) = BLKmode;
839 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
842 /* A record which has any BLKmode members must itself be BLKmode;
843 it can't go in a register.
844 Unless the member is BLKmode only because it isn't aligned. */
845 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
849 if (TREE_CODE (field) != FIELD_DECL)
852 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
853 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
856 if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
859 bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
861 /* Must be BLKmode if any field crosses a word boundary,
862 since extract_bit_field can't handle that in registers. */
863 if (bitpos / BITS_PER_WORD
864 != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
866 /* But there is no problem if the field is entire words. */
867 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
872 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
875 /* If structure's known alignment is less than
876 what the scalar mode would need, and it matters,
877 then stick with BLKmode. */
879 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
880 || (TYPE_ALIGN (type)
881 >= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
883 if (TYPE_MODE (type) != BLKmode)
884 /* If this is the only reason this type is BLKmode,
885 then don't force containing types to be BLKmode. */
886 TYPE_NO_FORCE_BLK (type) = 1;
887 TYPE_MODE (type) = BLKmode;
893 /* Lay out any static members. This is done now
894 because their type may use the record's type. */
895 while (pending_statics)
897 layout_decl (TREE_VALUE (pending_statics), 0);
898 pending_statics = TREE_CHAIN (pending_statics);
903 case QUAL_UNION_TYPE:
905 TYPE_MODE (type) = BLKmode;
906 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
907 /* If structure's known alignment is less than
908 what the scalar mode would need, and it matters,
909 then stick with BLKmode. */
910 && (! STRICT_ALIGNMENT
911 || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
912 || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
915 /* A union which has any BLKmode members must itself be BLKmode;
916 it can't go in a register.
917 Unless the member is BLKmode only because it isn't aligned. */
918 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
920 if (TREE_CODE (field) != FIELD_DECL)
923 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
924 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
929 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
936 /* Pascal and Chill types */
937 case BOOLEAN_TYPE: /* store one byte/boolean for now. */
938 TYPE_MODE (type) = QImode;
939 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
940 TYPE_PRECISION (type) = 1;
941 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
942 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
943 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
944 TREE_UNSIGNED (type) = 1;
948 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
949 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
953 #ifndef SET_WORD_SIZE
954 #define SET_WORD_SIZE BITS_PER_WORD
956 int alignment = set_alignment ? set_alignment : SET_WORD_SIZE;
958 TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
959 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1;
961 = ((size_in_bits + alignment - 1) / alignment) * alignment;
962 if (rounded_size > alignment)
963 TYPE_MODE (type) = BLKmode;
965 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
966 TYPE_SIZE (type) = size_int (rounded_size);
967 TYPE_ALIGN (type) = alignment;
968 TYPE_PRECISION (type) = size_in_bits;
973 /* The size may vary in different languages, so the language front end
974 should fill in the size. */
975 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
976 TYPE_MODE (type) = BLKmode;
983 /* Normally, use the alignment corresponding to the mode chosen.
984 However, where strict alignment is not required, avoid
985 over-aligning structures, since most compilers do not do this
988 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
990 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
991 && TREE_CODE (type) != QUAL_UNION_TYPE
992 && TREE_CODE (type) != ARRAY_TYPE)))
993 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
995 /* Evaluate nonconstant size only once, either now or as soon as safe. */
996 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
997 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
999 /* Also layout any other variants of the type. */
1000 if (TYPE_NEXT_VARIANT (type)
1001 || type != TYPE_MAIN_VARIANT (type))
1004 /* Record layout info of this variant. */
1005 tree size = TYPE_SIZE (type);
1006 int align = TYPE_ALIGN (type);
1007 enum machine_mode mode = TYPE_MODE (type);
1009 /* Copy it into all variants. */
1010 for (variant = TYPE_MAIN_VARIANT (type);
1012 variant = TYPE_NEXT_VARIANT (variant))
1014 TYPE_SIZE (variant) = size;
1015 TYPE_ALIGN (variant) = align;
1016 TYPE_MODE (variant) = mode;
1021 resume_momentary (old);
1024 /* Create and return a type for signed integers of PRECISION bits. */
1027 make_signed_type (precision)
1030 register tree type = make_node (INTEGER_TYPE);
1032 TYPE_PRECISION (type) = precision;
1034 /* Create the extreme values based on the number of bits. */
1036 TYPE_MIN_VALUE (type)
1037 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1038 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1039 (((HOST_WIDE_INT) (-1)
1040 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1041 ? precision - HOST_BITS_PER_WIDE_INT - 1
1043 TYPE_MAX_VALUE (type)
1044 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1045 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1046 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1047 ? (((HOST_WIDE_INT) 1
1048 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1051 /* Give this type's extreme values this type as their type. */
1053 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1054 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1056 /* The first type made with this or `make_unsigned_type'
1057 is the type for size values. */
1064 /* Lay out the type: set its alignment, size, etc. */
1071 /* Create and return a type for unsigned integers of PRECISION bits. */
1074 make_unsigned_type (precision)
1077 register tree type = make_node (INTEGER_TYPE);
1079 TYPE_PRECISION (type) = precision;
1081 /* The first type made with this or `make_signed_type'
1082 is the type for size values. */
1089 fixup_unsigned_type (type);
1093 /* Set the extreme values of TYPE based on its precision in bits,
1094 then lay it out. Used when make_signed_type won't do
1095 because the tree code is not INTEGER_TYPE.
1096 E.g. for Pascal, when the -fsigned-char option is given. */
1099 fixup_signed_type (type)
1102 register int precision = TYPE_PRECISION (type);
1104 TYPE_MIN_VALUE (type)
1105 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1106 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1107 (((HOST_WIDE_INT) (-1)
1108 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1109 ? precision - HOST_BITS_PER_WIDE_INT - 1
1111 TYPE_MAX_VALUE (type)
1112 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1113 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1114 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1115 ? (((HOST_WIDE_INT) 1
1116 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1119 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1120 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1122 /* Lay out the type: set its alignment, size, etc. */
1127 /* Set the extreme values of TYPE based on its precision in bits,
1128 then lay it out. This is used both in `make_unsigned_type'
1129 and for enumeral types. */
1132 fixup_unsigned_type (type)
1135 register int precision = TYPE_PRECISION (type);
1137 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1138 TYPE_MAX_VALUE (type)
1139 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1140 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1141 precision - HOST_BITS_PER_WIDE_INT > 0
1142 ? ((unsigned HOST_WIDE_INT) ~0
1143 >> (HOST_BITS_PER_WIDE_INT
1144 - (precision - HOST_BITS_PER_WIDE_INT)))
1146 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1147 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1149 /* Lay out the type: set its alignment, size, etc. */
1154 /* Find the best machine mode to use when referencing a bit field of length
1155 BITSIZE bits starting at BITPOS.
1157 The underlying object is known to be aligned to a boundary of ALIGN bits.
1158 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1159 larger than LARGEST_MODE (usually SImode).
1161 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1162 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1163 mode meeting these conditions.
1165 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1166 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1167 all the conditions. */
1170 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1171 int bitsize, bitpos;
1173 enum machine_mode largest_mode;
1176 enum machine_mode mode;
1179 /* Find the narrowest integer mode that contains the bit field. */
1180 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1181 mode = GET_MODE_WIDER_MODE (mode))
1183 unit = GET_MODE_BITSIZE (mode);
1184 if (bitpos / unit == (bitpos + bitsize - 1) / unit)
1188 if (mode == MAX_MACHINE_MODE
1189 /* It is tempting to omit the following line
1190 if STRICT_ALIGNMENT is true.
1191 But that is incorrect, since if the bitfield uses part of 3 bytes
1192 and we use a 4-byte mode, we could get a spurious segv
1193 if the extra 4th byte is past the end of memory.
1194 (Though at least one Unix compiler ignores this problem:
1195 that on the Sequent 386 machine. */
1196 || MIN (unit, BIGGEST_ALIGNMENT) > align
1197 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1200 if (SLOW_BYTE_ACCESS && ! volatilep)
1202 enum machine_mode wide_mode = VOIDmode, tmode;
1204 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1205 tmode = GET_MODE_WIDER_MODE (tmode))
1207 unit = GET_MODE_BITSIZE (tmode);
1208 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1209 && unit <= BITS_PER_WORD
1210 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1211 && (largest_mode == VOIDmode
1212 || unit <= GET_MODE_BITSIZE (largest_mode)))
1216 if (wide_mode != VOIDmode)
1223 /* Save all variables describing the current status into the structure *P.
1224 This is used before starting a nested function. */
1227 save_storage_status (p)
1230 #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
1231 p->pending_sizes = pending_sizes;
1232 p->immediate_size_expand = immediate_size_expand;
1236 /* Restore all variables describing the current status from the structure *P.
1237 This is used after a nested function. */
1240 restore_storage_status (p)
1244 pending_sizes = p->pending_sizes;
1245 immediate_size_expand = p->immediate_size_expand;