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_ALIGN (decl) >= TYPE_ALIGN (type))
289 DECL_BIT_FIELD (decl) = 0;
291 /* Evaluate nonconstant size only once, either now or as soon as safe. */
292 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
293 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
296 /* Lay out a RECORD_TYPE type (a C struct).
297 This means laying out the fields, determining their positions,
298 and computing the overall size and required alignment of the record.
299 Note that if you set the TYPE_ALIGN before calling this
300 then the struct is aligned to at least that boundary.
302 If the type has basetypes, you must call layout_basetypes
303 before calling this function.
305 The return value is a list of static members of the record.
306 They still need to be laid out. */
313 #ifdef STRUCTURE_SIZE_BOUNDARY
314 unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
316 unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
318 /* These must be laid out *after* the record is. */
319 tree pending_statics = NULL_TREE;
320 /* Record size so far is CONST_SIZE + VAR_SIZE bits,
321 where CONST_SIZE is an integer
322 and VAR_SIZE is a tree expression.
323 If VAR_SIZE is null, the size is just CONST_SIZE.
324 Naturally we try to avoid using VAR_SIZE. */
325 register int const_size = 0;
326 register tree var_size = 0;
327 /* Once we start using VAR_SIZE, this is the maximum alignment
328 that we know VAR_SIZE has. */
329 register int var_align = BITS_PER_UNIT;
332 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
334 register int known_align = var_size ? var_align : const_size;
335 register int desired_align;
337 /* If FIELD is static, then treat it like a separate variable,
338 not really like a structure field.
339 If it is a FUNCTION_DECL, it's a method.
340 In both cases, all we do is lay out the decl,
341 and we do it *after* the record is laid out. */
343 if (TREE_STATIC (field))
345 pending_statics = tree_cons (NULL_TREE, field, pending_statics);
348 /* Enumerators and enum types which are local to this class need not
349 be laid out. Likewise for initialized constant fields. */
350 if (TREE_CODE (field) != FIELD_DECL)
353 /* Lay out the field so we know what alignment it needs.
354 For a packed field, use the alignment as specified,
355 disregarding what the type would want. */
356 if (DECL_PACKED (field))
357 desired_align = DECL_ALIGN (field);
358 layout_decl (field, known_align);
359 if (! DECL_PACKED (field))
360 desired_align = DECL_ALIGN (field);
361 /* Some targets (i.e. VMS) limit struct field alignment
362 to a lower boundary than alignment of variables. */
363 #ifdef BIGGEST_FIELD_ALIGNMENT
364 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
366 #ifdef ADJUST_FIELD_ALIGN
367 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
370 /* Record must have at least as much alignment as any field.
371 Otherwise, the alignment of the field within the record
374 #ifndef PCC_BITFIELD_TYPE_MATTERS
375 record_align = MAX (record_align, desired_align);
377 if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
378 && DECL_BIT_FIELD_TYPE (field)
379 && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
381 /* For these machines, a zero-length field does not
382 affect the alignment of the structure as a whole.
383 It does, however, affect the alignment of the next field
384 within the structure. */
385 if (! integer_zerop (DECL_SIZE (field)))
386 record_align = MAX (record_align, desired_align);
387 else if (! DECL_PACKED (field))
388 desired_align = TYPE_ALIGN (TREE_TYPE (field));
389 /* A named bit field of declared type `int'
390 forces the entire structure to have `int' alignment. */
391 if (DECL_NAME (field) != 0)
393 int type_align = TYPE_ALIGN (TREE_TYPE (field));
394 if (maximum_field_alignment != 0)
395 type_align = MIN (type_align, maximum_field_alignment);
396 else if (TYPE_PACKED (rec))
397 type_align = MIN (type_align, BITS_PER_UNIT);
399 record_align = MAX (record_align, type_align);
403 record_align = MAX (record_align, desired_align);
406 /* Does this field automatically have alignment it needs
407 by virtue of the fields that precede it and the record's
410 if (const_size % desired_align != 0
411 || (var_align % desired_align != 0
414 /* No, we need to skip space before this field.
415 Bump the cumulative size to multiple of field alignment. */
418 || var_align % desired_align == 0)
420 = CEIL (const_size, desired_align) * desired_align;
424 var_size = size_binop (PLUS_EXPR, var_size,
425 size_int (const_size));
427 var_size = round_up (var_size, desired_align);
428 var_align = MIN (var_align, desired_align);
432 #ifdef PCC_BITFIELD_TYPE_MATTERS
433 if (PCC_BITFIELD_TYPE_MATTERS
434 && TREE_CODE (field) == FIELD_DECL
435 && TREE_TYPE (field) != error_mark_node
436 && DECL_BIT_FIELD_TYPE (field)
437 && !DECL_PACKED (field)
438 && maximum_field_alignment == 0
439 && !integer_zerop (DECL_SIZE (field)))
441 int type_align = TYPE_ALIGN (TREE_TYPE (field));
442 register tree dsize = DECL_SIZE (field);
443 int field_size = TREE_INT_CST_LOW (dsize);
445 /* A bit field may not span the unit of alignment of its type.
446 Advance to next boundary if necessary. */
447 /* ??? There is some uncertainty here as to what
448 should be done if type_align is less than the width of the type.
449 That can happen because the width exceeds BIGGEST_ALIGNMENT
450 or because it exceeds maximum_field_alignment. */
451 if (const_size / type_align
452 != (const_size + (field_size % type_align) - 1) / type_align)
453 const_size = CEIL (const_size, type_align) * type_align;
457 /* No existing machine description uses this parameter.
458 So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
459 #ifdef BITFIELD_NBYTES_LIMITED
460 if (BITFIELD_NBYTES_LIMITED
461 && TREE_CODE (field) == FIELD_DECL
462 && TREE_TYPE (field) != error_mark_node
463 && DECL_BIT_FIELD_TYPE (field)
464 && !DECL_PACKED (field)
465 && !integer_zerop (DECL_SIZE (field)))
467 int type_align = TYPE_ALIGN (TREE_TYPE (field));
468 register tree dsize = DECL_SIZE (field);
469 int field_size = TREE_INT_CST_LOW (dsize);
471 if (maximum_field_alignment != 0)
472 type_align = MIN (type_align, maximum_field_alignment);
473 else if (TYPE_PACKED (rec))
474 type_align = MIN (type_align, BITS_PER_UNIT);
476 /* A bit field may not span the unit of alignment of its type.
477 Advance to next boundary if necessary. */
478 if (const_size / type_align
479 != (const_size + field_size - 1) / type_align)
480 const_size = CEIL (const_size, type_align) * type_align;
484 /* Size so far becomes the position of this field. */
486 if (var_size && const_size)
487 DECL_FIELD_BITPOS (field)
488 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
490 DECL_FIELD_BITPOS (field) = var_size;
493 DECL_FIELD_BITPOS (field) = size_int (const_size);
495 /* If this field ended up more aligned than we thought it
496 would be (we approximate this by seeing if its position
497 changed), lay out the field again; perhaps we can use an
498 integral mode for it now. */
499 if (known_align != const_size)
500 layout_decl (field, const_size);
503 /* Now add size of this field to the size of the record. */
506 register tree dsize = DECL_SIZE (field);
508 /* This can happen when we have an invalid nested struct definition,
509 such as struct j { struct j { int i; } }. The error message is
510 printed in finish_struct. */
513 else if (TREE_CODE (dsize) == INTEGER_CST
514 && TREE_INT_CST_HIGH (dsize) == 0
515 && TREE_INT_CST_LOW (dsize) + const_size >= const_size)
516 /* Use const_size if there's no overflow. */
517 const_size += TREE_INT_CST_LOW (dsize);
523 var_size = size_binop (PLUS_EXPR, var_size, dsize);
528 /* Work out the total size and alignment of the record
529 as one expression and store in the record type.
530 Round it up to a multiple of the record's alignment. */
534 TYPE_SIZE (rec) = size_int (const_size);
540 = size_binop (PLUS_EXPR, var_size, size_int (const_size));
541 TYPE_SIZE (rec) = var_size;
544 /* Determine the desired alignment. */
545 #ifdef ROUND_TYPE_ALIGN
546 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
548 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
551 #ifdef ROUND_TYPE_SIZE
552 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
554 /* Round the size up to be a multiple of the required alignment */
555 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
558 return pending_statics;
561 /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
562 Lay out all the fields, set their positions to zero,
563 and compute the size and alignment of the union (maximum of any field).
564 Note that if you set the TYPE_ALIGN before calling this
565 then the union align is aligned to at least that boundary. */
572 #ifdef STRUCTURE_SIZE_BOUNDARY
573 unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
575 unsigned union_align = BITS_PER_UNIT;
578 /* The size of the union, based on the fields scanned so far,
579 is max (CONST_SIZE, VAR_SIZE).
580 VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
581 register int const_size = 0;
582 register tree var_size = 0;
584 /* If this is a QUAL_UNION_TYPE, we want to process the fields in
585 the reverse order in building the COND_EXPR that denotes its
586 size. We reverse them again later. */
587 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
588 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
590 for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
592 /* Enums which are local to this class need not be laid out. */
593 if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
596 layout_decl (field, 0);
597 DECL_FIELD_BITPOS (field) = size_int (0);
599 /* Union must be at least as aligned as any field requires. */
601 union_align = MAX (union_align, DECL_ALIGN (field));
603 #ifdef PCC_BITFIELD_TYPE_MATTERS
604 /* On the m88000, a bit field of declare type `int'
605 forces the entire union to have `int' alignment. */
606 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
607 union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
610 if (TREE_CODE (rec) == UNION_TYPE)
612 /* Set union_size to max (decl_size, union_size).
613 There are more and less general ways to do this.
614 Use only CONST_SIZE unless forced to use VAR_SIZE. */
616 if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
618 = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
619 else if (var_size == 0)
620 var_size = DECL_SIZE (field);
622 var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
624 else if (TREE_CODE (rec) == QUAL_UNION_TYPE)
625 var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field),
627 var_size ? var_size : integer_zero_node));
630 if (TREE_CODE (rec) == QUAL_UNION_TYPE)
631 TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
633 /* Determine the ultimate size of the union (in bytes). */
634 if (NULL == var_size)
635 TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
637 else if (const_size == 0)
638 TYPE_SIZE (rec) = var_size;
640 TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
641 round_up (size_int (const_size),
644 /* Determine the desired alignment. */
645 #ifdef ROUND_TYPE_ALIGN
646 TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
648 TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
651 #ifdef ROUND_TYPE_SIZE
652 TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
654 /* Round the size up to be a multiple of the required alignment */
655 TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
659 /* Calculate the mode, size, and alignment for TYPE.
660 For an array type, calculate the element separation as well.
661 Record TYPE on the chain of permanent or temporary types
662 so that dbxout will find out about it.
664 TYPE_SIZE of a type is nonzero if the type has been laid out already.
665 layout_type does nothing on such a type.
667 If the type is incomplete, its TYPE_SIZE remains zero. */
674 tree pending_statics;
679 /* Do nothing if type has been laid out before. */
680 if (TYPE_SIZE (type))
683 /* Make sure all nodes we allocate are not momentary;
684 they must last past the current statement. */
685 old = suspend_momentary ();
687 /* Put all our nodes into the same obstack as the type. Also,
688 make expressions saveable (this is a no-op for permanent types). */
690 push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type));
691 saveable_allocation ();
693 switch (TREE_CODE (type))
696 /* This kind of type is the responsibility
697 of the language-specific code. */
703 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
704 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
705 TREE_UNSIGNED (type) = 1;
707 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
709 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
713 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
714 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
718 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
720 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
721 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
722 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
724 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
728 TYPE_SIZE (type) = size_zero_node;
729 TYPE_ALIGN (type) = 1;
730 TYPE_MODE (type) = VOIDmode;
734 TYPE_SIZE (type) = size_int (POINTER_SIZE);
735 TYPE_MODE (type) = ptr_mode;
740 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
741 TYPE_SIZE (type) = size_int (2 * POINTER_SIZE);
746 TYPE_MODE (type) = ptr_mode;
747 TYPE_SIZE (type) = size_int (POINTER_SIZE);
748 TREE_UNSIGNED (type) = 1;
749 TYPE_PRECISION (type) = POINTER_SIZE;
754 register tree index = TYPE_DOMAIN (type);
755 register tree element = TREE_TYPE (type);
757 build_pointer_type (element);
759 /* We need to know both bounds in order to compute the size. */
760 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
761 && TYPE_SIZE (element))
763 tree ub = TYPE_MAX_VALUE (index);
764 tree lb = TYPE_MIN_VALUE (index);
767 /* If UB is max (lb - 1, x), remove the MAX_EXPR since the
768 test for negative below covers it. */
769 if (TREE_CODE (ub) == MAX_EXPR
770 && TREE_CODE (TREE_OPERAND (ub, 0)) == MINUS_EXPR
771 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 0), 1))
772 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 0), 0),
774 ub = TREE_OPERAND (ub, 1);
775 else if (TREE_CODE (ub) == MAX_EXPR
776 && TREE_CODE (TREE_OPERAND (ub, 1)) == MINUS_EXPR
777 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 1), 1))
778 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 1),
781 ub = TREE_OPERAND (ub, 0);
783 length = size_binop (PLUS_EXPR, size_one_node,
784 size_binop (MINUS_EXPR, ub, lb));
786 /* If neither bound is a constant and sizetype is signed, make
787 sure the size is never negative. We should really do this
788 if *either* bound is non-constant, but this is the best
789 compromise between C and Ada. */
790 if (! TREE_UNSIGNED (sizetype)
791 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
792 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
793 length = size_binop (MAX_EXPR, length, size_zero_node);
795 TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
796 TYPE_SIZE (element));
799 /* Now round the alignment and size,
800 using machine-dependent criteria if any. */
802 #ifdef ROUND_TYPE_ALIGN
804 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
806 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
809 #ifdef ROUND_TYPE_SIZE
810 if (TYPE_SIZE (type) != 0)
812 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
815 TYPE_MODE (type) = BLKmode;
816 if (TYPE_SIZE (type) != 0
817 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
818 /* BLKmode elements force BLKmode aggregate;
819 else extract/store fields may lose. */
820 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
821 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
824 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
827 if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
828 && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
829 && TYPE_MODE (type) != BLKmode)
831 TYPE_NO_FORCE_BLK (type) = 1;
832 TYPE_MODE (type) = BLKmode;
839 pending_statics = layout_record (type);
840 TYPE_MODE (type) = BLKmode;
841 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
844 /* A record which has any BLKmode members must itself be BLKmode;
845 it can't go in a register.
846 Unless the member is BLKmode only because it isn't aligned. */
847 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
851 if (TREE_CODE (field) != FIELD_DECL)
854 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
855 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
858 if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
861 bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
863 /* Must be BLKmode if any field crosses a word boundary,
864 since extract_bit_field can't handle that in registers. */
865 if (bitpos / BITS_PER_WORD
866 != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
868 /* But there is no problem if the field is entire words. */
869 && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
874 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
877 /* If structure's known alignment is less than
878 what the scalar mode would need, and it matters,
879 then stick with BLKmode. */
881 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
882 || (TYPE_ALIGN (type)
883 >= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
885 if (TYPE_MODE (type) != BLKmode)
886 /* If this is the only reason this type is BLKmode,
887 then don't force containing types to be BLKmode. */
888 TYPE_NO_FORCE_BLK (type) = 1;
889 TYPE_MODE (type) = BLKmode;
895 /* Lay out any static members. This is done now
896 because their type may use the record's type. */
897 while (pending_statics)
899 layout_decl (TREE_VALUE (pending_statics), 0);
900 pending_statics = TREE_CHAIN (pending_statics);
905 case QUAL_UNION_TYPE:
907 TYPE_MODE (type) = BLKmode;
908 if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
909 /* If structure's known alignment is less than
910 what the scalar mode would need, and it matters,
911 then stick with BLKmode. */
912 && (! STRICT_ALIGNMENT
913 || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
914 || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
917 /* A union which has any BLKmode members must itself be BLKmode;
918 it can't go in a register.
919 Unless the member is BLKmode only because it isn't aligned. */
920 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
922 if (TREE_CODE (field) != FIELD_DECL)
925 if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
926 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
931 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
938 /* Pascal and Chill types */
939 case BOOLEAN_TYPE: /* store one byte/boolean for now. */
940 TYPE_MODE (type) = QImode;
941 TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
942 TYPE_PRECISION (type) = 1;
943 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
944 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
945 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
946 TREE_UNSIGNED (type) = 1;
950 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
951 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
955 #ifndef SET_WORD_SIZE
956 #define SET_WORD_SIZE BITS_PER_WORD
958 int alignment = set_alignment ? set_alignment : SET_WORD_SIZE;
960 TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
961 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1;
963 = ((size_in_bits + alignment - 1) / alignment) * alignment;
964 if (rounded_size > alignment)
965 TYPE_MODE (type) = BLKmode;
967 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
968 TYPE_SIZE (type) = size_int (rounded_size);
969 TYPE_ALIGN (type) = alignment;
970 TYPE_PRECISION (type) = size_in_bits;
975 /* The size may vary in different languages, so the language front end
976 should fill in the size. */
977 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
978 TYPE_MODE (type) = BLKmode;
985 /* Normally, use the alignment corresponding to the mode chosen.
986 However, where strict alignment is not required, avoid
987 over-aligning structures, since most compilers do not do this
990 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
992 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
993 && TREE_CODE (type) != QUAL_UNION_TYPE
994 && TREE_CODE (type) != ARRAY_TYPE)))
995 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
997 /* Evaluate nonconstant size only once, either now or as soon as safe. */
998 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
999 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1001 /* Also layout any other variants of the type. */
1002 if (TYPE_NEXT_VARIANT (type)
1003 || type != TYPE_MAIN_VARIANT (type))
1006 /* Record layout info of this variant. */
1007 tree size = TYPE_SIZE (type);
1008 int align = TYPE_ALIGN (type);
1009 enum machine_mode mode = TYPE_MODE (type);
1011 /* Copy it into all variants. */
1012 for (variant = TYPE_MAIN_VARIANT (type);
1014 variant = TYPE_NEXT_VARIANT (variant))
1016 TYPE_SIZE (variant) = size;
1017 TYPE_ALIGN (variant) = align;
1018 TYPE_MODE (variant) = mode;
1023 resume_momentary (old);
1026 /* Create and return a type for signed integers of PRECISION bits. */
1029 make_signed_type (precision)
1032 register tree type = make_node (INTEGER_TYPE);
1034 TYPE_PRECISION (type) = precision;
1036 /* Create the extreme values based on the number of bits. */
1038 TYPE_MIN_VALUE (type)
1039 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1040 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1041 (((HOST_WIDE_INT) (-1)
1042 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1043 ? precision - HOST_BITS_PER_WIDE_INT - 1
1045 TYPE_MAX_VALUE (type)
1046 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1047 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1048 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1049 ? (((HOST_WIDE_INT) 1
1050 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1053 /* Give this type's extreme values this type as their type. */
1055 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1056 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1058 /* The first type made with this or `make_unsigned_type'
1059 is the type for size values. */
1066 /* Lay out the type: set its alignment, size, etc. */
1073 /* Create and return a type for unsigned integers of PRECISION bits. */
1076 make_unsigned_type (precision)
1079 register tree type = make_node (INTEGER_TYPE);
1081 TYPE_PRECISION (type) = precision;
1083 /* The first type made with this or `make_signed_type'
1084 is the type for size values. */
1091 fixup_unsigned_type (type);
1095 /* Set the extreme values of TYPE based on its precision in bits,
1096 then lay it out. Used when make_signed_type won't do
1097 because the tree code is not INTEGER_TYPE.
1098 E.g. for Pascal, when the -fsigned-char option is given. */
1101 fixup_signed_type (type)
1104 register int precision = TYPE_PRECISION (type);
1106 TYPE_MIN_VALUE (type)
1107 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1108 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1109 (((HOST_WIDE_INT) (-1)
1110 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1111 ? precision - HOST_BITS_PER_WIDE_INT - 1
1113 TYPE_MAX_VALUE (type)
1114 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1115 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1116 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1117 ? (((HOST_WIDE_INT) 1
1118 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1121 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1122 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1124 /* Lay out the type: set its alignment, size, etc. */
1129 /* Set the extreme values of TYPE based on its precision in bits,
1130 then lay it out. This is used both in `make_unsigned_type'
1131 and for enumeral types. */
1134 fixup_unsigned_type (type)
1137 register int precision = TYPE_PRECISION (type);
1139 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1140 TYPE_MAX_VALUE (type)
1141 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1142 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1143 precision - HOST_BITS_PER_WIDE_INT > 0
1144 ? ((unsigned HOST_WIDE_INT) ~0
1145 >> (HOST_BITS_PER_WIDE_INT
1146 - (precision - HOST_BITS_PER_WIDE_INT)))
1148 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1149 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1151 /* Lay out the type: set its alignment, size, etc. */
1156 /* Find the best machine mode to use when referencing a bit field of length
1157 BITSIZE bits starting at BITPOS.
1159 The underlying object is known to be aligned to a boundary of ALIGN bits.
1160 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1161 larger than LARGEST_MODE (usually SImode).
1163 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1164 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1165 mode meeting these conditions.
1167 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1168 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1169 all the conditions. */
1172 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1173 int bitsize, bitpos;
1175 enum machine_mode largest_mode;
1178 enum machine_mode mode;
1181 /* Find the narrowest integer mode that contains the bit field. */
1182 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1183 mode = GET_MODE_WIDER_MODE (mode))
1185 unit = GET_MODE_BITSIZE (mode);
1186 if (bitpos / unit == (bitpos + bitsize - 1) / unit)
1190 if (mode == MAX_MACHINE_MODE
1191 /* It is tempting to omit the following line
1192 if STRICT_ALIGNMENT is true.
1193 But that is incorrect, since if the bitfield uses part of 3 bytes
1194 and we use a 4-byte mode, we could get a spurious segv
1195 if the extra 4th byte is past the end of memory.
1196 (Though at least one Unix compiler ignores this problem:
1197 that on the Sequent 386 machine. */
1198 || MIN (unit, BIGGEST_ALIGNMENT) > align
1199 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1202 if (SLOW_BYTE_ACCESS && ! volatilep)
1204 enum machine_mode wide_mode = VOIDmode, tmode;
1206 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1207 tmode = GET_MODE_WIDER_MODE (tmode))
1209 unit = GET_MODE_BITSIZE (tmode);
1210 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1211 && unit <= BITS_PER_WORD
1212 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1213 && (largest_mode == VOIDmode
1214 || unit <= GET_MODE_BITSIZE (largest_mode)))
1218 if (wide_mode != VOIDmode)
1225 /* Save all variables describing the current status into the structure *P.
1226 This is used before starting a nested function. */
1229 save_storage_status (p)
1232 #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
1233 p->pending_sizes = pending_sizes;
1234 p->immediate_size_expand = immediate_size_expand;
1238 /* Restore all variables describing the current status from the structure *P.
1239 This is used after a nested function. */
1242 restore_storage_status (p)
1246 pending_sizes = p->pending_sizes;
1247 immediate_size_expand = p->immediate_size_expand;