1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1996, 1998,
3 1999, 2000 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
34 /* Set to one when set_sizetype has been called. */
35 static int sizetype_set;
37 /* List of types created before set_sizetype has been called. We do not
38 make this a GGC root since we want these nodes to be reclaimed. */
39 static tree early_type_list;
41 /* Data type for the expressions representing sizes of data types.
42 It is the first integer type laid out. */
43 tree sizetype_tab[(int) TYPE_KIND_LAST];
45 /* If nonzero, this is an upper limit on alignment of structure fields.
46 The value is measured in bits. */
47 unsigned 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 unsigned int set_alignment = 0;
53 static void finalize_record_size PARAMS ((record_layout_info));
54 static void finalize_type_size PARAMS ((tree));
55 static void place_union_field PARAMS ((record_layout_info, tree));
57 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
59 static tree pending_sizes;
61 /* Nonzero means cannot safely call expand_expr now,
62 so put variable sizes onto `pending_sizes' instead. */
64 int immediate_size_expand;
66 /* Get a list of all the objects put on the pending sizes list. */
71 tree chain = pending_sizes;
74 /* Put each SAVE_EXPR into the current function. */
75 for (t = chain; t; t = TREE_CHAIN (t))
76 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
82 /* Put a chain of objects into the pending sizes list, which must be
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 an array with a variable number of elements is declared, and
112 the elements require destruction, we will emit a cleanup for the
113 array. That cleanup is run both on normal exit from the block
114 and in the exception-handler for the block. Normally, when code
115 is used in both ordinary code and in an exception handler it is
116 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
117 not wish to do that here; the array-size is the same in both
119 if (TREE_CODE (size) == SAVE_EXPR)
120 SAVE_EXPR_PERSISTENT_P (size) = 1;
122 if (global_bindings_p ())
124 if (TREE_CONSTANT (size))
125 error ("type size can't be explicitly evaluated");
127 error ("variable-size type declared outside of any function");
129 return size_one_node;
132 if (immediate_size_expand)
133 /* NULL_RTX is not defined; neither is the rtx type.
134 Also, we would like to pass const0_rtx here, but don't have it. */
135 expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
137 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
138 /* The front-end doesn't want us to keep a list of the expressions
139 that determine sizes for variable size objects. */
142 pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
147 #ifndef MAX_FIXED_MODE_SIZE
148 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
151 /* Return the machine mode to use for a nonscalar of SIZE bits.
152 The mode must be in class CLASS, and have exactly that many bits.
153 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
157 mode_for_size (size, class, limit)
159 enum mode_class class;
162 register enum machine_mode mode;
164 if (limit && size > MAX_FIXED_MODE_SIZE)
167 /* Get the first mode which has this size, in the specified class. */
168 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
169 mode = GET_MODE_WIDER_MODE (mode))
170 if (GET_MODE_BITSIZE (mode) == size)
176 /* Similar, except passed a tree node. */
179 mode_for_size_tree (size, class, limit)
181 enum mode_class class;
184 if (TREE_CODE (size) != INTEGER_CST
185 /* What we really want to say here is that the size can fit in a
186 host integer, but we know there's no way we'd find a mode for
187 this many bits, so there's no point in doing the precise test. */
188 || compare_tree_int (size, 1000) > 0)
191 return mode_for_size (TREE_INT_CST_LOW (size), class, limit);
194 /* Similar, but never return BLKmode; return the narrowest mode that
195 contains at least the requested number of bits. */
198 smallest_mode_for_size (size, class)
200 enum mode_class class;
202 register enum machine_mode mode;
204 /* Get the first mode which has at least this size, in the
206 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
207 mode = GET_MODE_WIDER_MODE (mode))
208 if (GET_MODE_BITSIZE (mode) >= size)
214 /* Find an integer mode of the exact same size, or BLKmode on failure. */
217 int_mode_for_mode (mode)
218 enum machine_mode mode;
220 switch (GET_MODE_CLASS (mode))
223 case MODE_PARTIAL_INT:
226 case MODE_COMPLEX_INT:
227 case MODE_COMPLEX_FLOAT:
229 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
236 /* ... fall through ... */
246 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
247 This can only be applied to objects of a sizetype. */
250 round_up (value, divisor)
254 tree arg = size_int_type (divisor, TREE_TYPE (value));
256 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
259 /* Likewise, but round down. */
262 round_down (value, divisor)
266 tree arg = size_int_type (divisor, TREE_TYPE (value));
268 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
271 /* Set the size, mode and alignment of a ..._DECL node.
272 TYPE_DECL does need this for C++.
273 Note that LABEL_DECL and CONST_DECL nodes do not need this,
274 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
275 Don't call layout_decl for them.
277 KNOWN_ALIGN is the amount of alignment we can assume this
278 decl has with no special effort. It is relevant only for FIELD_DECLs
279 and depends on the previous fields.
280 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
281 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
282 the record will be aligned to suit. */
285 layout_decl (decl, known_align)
287 unsigned int known_align;
289 register tree type = TREE_TYPE (decl);
290 register enum tree_code code = TREE_CODE (decl);
292 if (code == CONST_DECL)
294 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
295 && code != TYPE_DECL && code != FIELD_DECL)
298 if (type == error_mark_node)
299 type = void_type_node;
301 /* Usually the size and mode come from the data type without change,
302 however, the front-end may set the explicit width of the field, so its
303 size may not be the same as the size of its type. This happens with
304 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
305 also happens with other fields. For example, the C++ front-end creates
306 zero-sized fields corresponding to empty base classes, and depends on
307 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
308 size in bytes from the size in bits. If we have already set the mode,
309 don't set it again since we can be called twice for FIELD_DECLs. */
311 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
312 if (DECL_MODE (decl) == VOIDmode)
313 DECL_MODE (decl) = TYPE_MODE (type);
315 if (DECL_SIZE (decl) == 0)
317 DECL_SIZE (decl) = TYPE_SIZE (type);
318 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
321 DECL_SIZE_UNIT (decl)
322 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
325 /* Force alignment required for the data type.
326 But if the decl itself wants greater alignment, don't override that.
327 Likewise, if the decl is packed, don't override it. */
328 if (! (code == FIELD_DECL && DECL_BIT_FIELD (decl))
329 && (DECL_ALIGN (decl) == 0
330 || (! (code == FIELD_DECL && DECL_PACKED (decl))
331 && TYPE_ALIGN (type) > DECL_ALIGN (decl))))
332 DECL_ALIGN (decl) = TYPE_ALIGN (type);
334 /* For fields, set the bit field type and update the alignment. */
335 if (code == FIELD_DECL)
337 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
338 if (maximum_field_alignment != 0)
339 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
340 else if (DECL_PACKED (decl))
341 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
344 /* See if we can use an ordinary integer mode for a bit-field.
345 Conditions are: a fixed size that is correct for another mode
346 and occupying a complete byte or bytes on proper boundary. */
347 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
348 && TYPE_SIZE (type) != 0
349 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
350 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
352 register enum machine_mode xmode
353 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
355 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
357 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
359 DECL_MODE (decl) = xmode;
360 DECL_BIT_FIELD (decl) = 0;
364 /* Turn off DECL_BIT_FIELD if we won't need it set. */
365 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
366 && TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
367 && known_align >= TYPE_ALIGN (type)
368 && DECL_ALIGN (decl) >= TYPE_ALIGN (type)
369 && DECL_SIZE_UNIT (decl) != 0)
370 DECL_BIT_FIELD (decl) = 0;
372 /* Evaluate nonconstant size only once, either now or as soon as safe. */
373 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
374 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
375 if (DECL_SIZE_UNIT (decl) != 0
376 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
377 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
379 /* If requested, warn about definitions of large data objects. */
381 && (code == VAR_DECL || code == PARM_DECL)
382 && ! DECL_EXTERNAL (decl))
384 tree size = DECL_SIZE_UNIT (decl);
386 if (size != 0 && TREE_CODE (size) == INTEGER_CST
387 && compare_tree_int (size, larger_than_size) > 0)
389 unsigned int size_as_int = TREE_INT_CST_LOW (size);
391 if (compare_tree_int (size, size_as_int) == 0)
392 warning_with_decl (decl, "size of `%s' is %d bytes", size_as_int);
394 warning_with_decl (decl, "size of `%s' is larger than %d bytes",
400 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
401 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
402 is to be passed to all other layout functions for this record. It is the
403 responsibility of the caller to call `free' for the storage returned.
404 Note that garbage collection is not permitted until we finish laying
408 start_record_layout (t)
411 record_layout_info rli
412 = (record_layout_info) xmalloc (sizeof (struct record_layout_info));
416 /* If the type has a minimum specified alignment (via an attribute
417 declaration, for example) use it -- otherwise, start with a
418 one-byte alignment. */
419 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
420 rli->unpacked_align = rli->record_align;
421 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
423 #ifdef STRUCTURE_SIZE_BOUNDARY
424 /* Packed structures don't need to have minimum size. */
425 if (! TYPE_PACKED (t))
426 rli->record_align = MAX (rli->record_align, STRUCTURE_SIZE_BOUNDARY);
429 rli->offset = size_zero_node;
430 rli->bitpos = bitsize_zero_node;
431 rli->pending_statics = 0;
432 rli->packed_maybe_necessary = 0;
437 /* These four routines perform computations that convert between
438 the offset/bitpos forms and byte and bit offsets. */
441 bit_from_pos (offset, bitpos)
444 return size_binop (PLUS_EXPR, bitpos,
445 size_binop (MULT_EXPR, convert (bitsizetype, offset),
450 byte_from_pos (offset, bitpos)
453 return size_binop (PLUS_EXPR, offset,
455 size_binop (TRUNC_DIV_EXPR, bitpos,
456 bitsize_unit_node)));
460 pos_from_byte (poffset, pbitpos, off_align, pos)
461 tree *poffset, *pbitpos;
462 unsigned int off_align;
466 = size_binop (MULT_EXPR,
468 size_binop (FLOOR_DIV_EXPR, pos,
469 bitsize_int (off_align
471 size_int (off_align / BITS_PER_UNIT));
472 *pbitpos = size_binop (MULT_EXPR,
473 size_binop (FLOOR_MOD_EXPR, pos,
474 bitsize_int (off_align / BITS_PER_UNIT)),
479 pos_from_bit (poffset, pbitpos, off_align, pos)
480 tree *poffset, *pbitpos;
481 unsigned int off_align;
484 *poffset = size_binop (MULT_EXPR,
486 size_binop (FLOOR_DIV_EXPR, pos,
487 bitsize_int (off_align))),
488 size_int (off_align / BITS_PER_UNIT));
489 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
492 /* Given a pointer to bit and byte offsets and an offset alignment,
493 normalize the offsets so they are within the alignment. */
496 normalize_offset (poffset, pbitpos, off_align)
497 tree *poffset, *pbitpos;
498 unsigned int off_align;
500 /* If the bit position is now larger than it should be, adjust it
502 if (compare_tree_int (*pbitpos, off_align) >= 0)
504 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
505 bitsize_int (off_align));
508 = size_binop (PLUS_EXPR, *poffset,
509 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
510 size_int (off_align / BITS_PER_UNIT)));
513 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
517 /* Print debugging information about the information in RLI. */
521 record_layout_info rli;
523 print_node_brief (stderr, "type", rli->t, 0);
524 print_node_brief (stderr, "\noffset", rli->offset, 0);
525 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
527 fprintf (stderr, "\nrec_align = %u, unpack_align = %u, off_align = %u\n",
528 rli->record_align, rli->unpacked_align, rli->offset_align);
529 if (rli->packed_maybe_necessary)
530 fprintf (stderr, "packed may be necessary\n");
532 if (rli->pending_statics)
534 fprintf (stderr, "pending statics:\n");
535 debug_tree (rli->pending_statics);
539 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
540 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
544 record_layout_info rli;
546 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
549 /* Returns the size in bytes allocated so far. */
552 rli_size_unit_so_far (rli)
553 record_layout_info rli;
555 return byte_from_pos (rli->offset, rli->bitpos);
558 /* Returns the size in bits allocated so far. */
561 rli_size_so_far (rli)
562 record_layout_info rli;
564 return bit_from_pos (rli->offset, rli->bitpos);
567 /* Called from place_field to handle unions. */
570 place_union_field (rli, field)
571 record_layout_info rli;
574 layout_decl (field, 0);
576 DECL_FIELD_OFFSET (field) = size_zero_node;
577 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
578 DECL_OFFSET_ALIGN (field) = BIGGEST_ALIGNMENT;
580 /* Union must be at least as aligned as any field requires. */
581 rli->record_align = MAX (rli->record_align, DECL_ALIGN (field));
583 #ifdef PCC_BITFIELD_TYPE_MATTERS
584 /* On the m88000, a bit field of declare type `int' forces the
585 entire union to have `int' alignment. */
586 if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
587 rli->record_align = MAX (rli->record_align,
588 TYPE_ALIGN (TREE_TYPE (field)));
591 /* We assume the union's size will be a multiple of a byte so we don't
592 bother with BITPOS. */
593 if (TREE_CODE (rli->t) == UNION_TYPE)
594 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
595 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
596 rli->offset = fold (build (COND_EXPR, sizetype,
597 DECL_QUALIFIER (field),
598 DECL_SIZE_UNIT (field), rli->offset));
601 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
602 is a FIELD_DECL to be added after those fields already present in
603 T. (FIELD is not actually added to the TYPE_FIELDS list here;
604 callers that desire that behavior must manually perform that step.) */
607 place_field (rli, field)
608 record_layout_info rli;
611 /* The alignment required for FIELD. */
612 unsigned int desired_align;
613 /* The alignment FIELD would have if we just dropped it into the
614 record as it presently stands. */
615 unsigned int known_align;
616 unsigned int actual_align;
617 /* The type of this field. */
618 tree type = TREE_TYPE (field);
620 /* If FIELD is static, then treat it like a separate variable, not
621 really like a structure field. If it is a FUNCTION_DECL, it's a
622 method. In both cases, all we do is lay out the decl, and we do
623 it *after* the record is laid out. */
624 if (TREE_CODE (field) == VAR_DECL)
626 rli->pending_statics = tree_cons (NULL_TREE, field,
627 rli->pending_statics);
631 /* Enumerators and enum types which are local to this class need not
632 be laid out. Likewise for initialized constant fields. */
633 else if (TREE_CODE (field) != FIELD_DECL)
636 /* Unions are laid out very differently than records, so split
637 that code off to another function. */
638 else if (TREE_CODE (rli->t) != RECORD_TYPE)
640 place_union_field (rli, field);
644 /* Work out the known alignment so far. Note that A & (-A) is the
645 value of the least-significant bit in A that is one. */
646 if (! integer_zerop (rli->bitpos))
647 known_align = (tree_low_cst (rli->bitpos, 1)
648 & - tree_low_cst (rli->bitpos, 1));
649 else if (integer_zerop (rli->offset))
650 known_align = BIGGEST_ALIGNMENT;
651 else if (host_integerp (rli->offset, 1))
652 known_align = (BITS_PER_UNIT
653 * (tree_low_cst (rli->offset, 1)
654 & - tree_low_cst (rli->offset, 1)));
656 known_align = rli->offset_align;
658 /* Lay out the field so we know what alignment it needs. For a
659 packed field, use the alignment as specified, disregarding what
660 the type would want. */
661 desired_align = DECL_ALIGN (field);
662 layout_decl (field, known_align);
663 if (! DECL_PACKED (field))
664 desired_align = DECL_ALIGN (field);
666 /* Some targets (i.e. VMS) limit struct field alignment
667 to a lower boundary than alignment of variables. */
668 #ifdef BIGGEST_FIELD_ALIGNMENT
669 desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
671 #ifdef ADJUST_FIELD_ALIGN
672 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
675 /* Record must have at least as much alignment as any field.
676 Otherwise, the alignment of the field within the record is
678 #ifdef PCC_BITFIELD_TYPE_MATTERS
679 if (PCC_BITFIELD_TYPE_MATTERS && type != error_mark_node
680 && DECL_BIT_FIELD_TYPE (field)
681 && ! integer_zerop (TYPE_SIZE (type)))
683 /* For these machines, a zero-length field does not
684 affect the alignment of the structure as a whole.
685 It does, however, affect the alignment of the next field
686 within the structure. */
687 if (! integer_zerop (DECL_SIZE (field)))
688 rli->record_align = MAX (rli->record_align, desired_align);
689 else if (! DECL_PACKED (field))
690 desired_align = TYPE_ALIGN (type);
692 /* A named bit field of declared type `int'
693 forces the entire structure to have `int' alignment. */
694 if (DECL_NAME (field) != 0)
696 unsigned int type_align = TYPE_ALIGN (type);
698 if (maximum_field_alignment != 0)
699 type_align = MIN (type_align, maximum_field_alignment);
700 else if (DECL_PACKED (field))
701 type_align = MIN (type_align, BITS_PER_UNIT);
703 rli->record_align = MAX (rli->record_align, type_align);
705 rli->unpacked_align = MAX (rli->unpacked_align,
712 rli->record_align = MAX (rli->record_align, desired_align);
713 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
716 if (warn_packed && DECL_PACKED (field))
718 if (known_align > TYPE_ALIGN (type))
720 if (TYPE_ALIGN (type) > desired_align)
722 if (STRICT_ALIGNMENT)
723 warning_with_decl (field, "packed attribute causes inefficient alignment for `%s'");
725 warning_with_decl (field, "packed attribute is unnecessary for `%s'");
729 rli->packed_maybe_necessary = 1;
732 /* Does this field automatically have alignment it needs by virtue
733 of the fields that precede it and the record's own alignment? */
734 if (known_align < desired_align)
736 /* No, we need to skip space before this field.
737 Bump the cumulative size to multiple of field alignment. */
740 warning_with_decl (field, "padding struct to align `%s'");
742 /* If the alignment is still within offset_align, just align
744 if (desired_align < rli->offset_align)
745 rli->bitpos = round_up (rli->bitpos, desired_align);
748 /* First adjust OFFSET by the partial bits, then align. */
750 = size_binop (PLUS_EXPR, rli->offset,
752 size_binop (CEIL_DIV_EXPR, rli->bitpos,
753 bitsize_unit_node)));
754 rli->bitpos = bitsize_zero_node;
756 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
759 if (! TREE_CONSTANT (rli->offset))
760 rli->offset_align = desired_align;
764 /* Handle compatibility with PCC. Note that if the record has any
765 variable-sized fields, we need not worry about compatibility. */
766 #ifdef PCC_BITFIELD_TYPE_MATTERS
767 if (PCC_BITFIELD_TYPE_MATTERS
768 && TREE_CODE (field) == FIELD_DECL
769 && type != error_mark_node
770 && DECL_BIT_FIELD (field)
771 && ! DECL_PACKED (field)
772 && maximum_field_alignment == 0
773 && ! integer_zerop (DECL_SIZE (field))
774 && host_integerp (DECL_SIZE (field), 1)
775 && host_integerp (rli->offset, 1)
776 && host_integerp (TYPE_SIZE (type), 1))
778 unsigned int type_align = TYPE_ALIGN (type);
779 tree dsize = DECL_SIZE (field);
780 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
781 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
782 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
784 /* A bit field may not span more units of alignment of its type
785 than its type itself. Advance to next boundary if necessary. */
786 if ((((offset * BITS_PER_UNIT + bit_offset + field_size +
789 - (offset * BITS_PER_UNIT + bit_offset) / type_align)
790 > tree_low_cst (TYPE_SIZE (type), 1) / type_align)
791 rli->bitpos = round_up (rli->bitpos, type_align);
795 #ifdef BITFIELD_NBYTES_LIMITED
796 if (BITFIELD_NBYTES_LIMITED
797 && TREE_CODE (field) == FIELD_DECL
798 && type != error_mark_node
799 && DECL_BIT_FIELD_TYPE (field)
800 && ! DECL_PACKED (field)
801 && ! integer_zerop (DECL_SIZE (field))
802 && host_integerp (DECL_SIZE (field), 1)
803 && host_integerp (rli->size, 1)
804 && host_integerp (TYPE_SIZE (type), 1))
806 unsigned int type_align = TYPE_ALIGN (type);
807 tree dsize = DECL_SIZE (field);
808 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
809 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
810 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
812 if (maximum_field_alignment != 0)
813 type_align = MIN (type_align, maximum_field_alignment);
814 /* ??? This test is opposite the test in the containing if
815 statement, so this code is unreachable currently. */
816 else if (DECL_PACKED (field))
817 type_align = MIN (type_align, BITS_PER_UNIT);
819 /* A bit field may not span the unit of alignment of its type.
820 Advance to next boundary if necessary. */
821 /* ??? This code should match the code above for the
822 PCC_BITFIELD_TYPE_MATTERS case. */
823 if ((offset * BITS_PER_UNIT + bit_offset) / type_align
824 != ((offset * BITS_PER_UNIT + bit_offset + field_size - 1)
826 rli->bitpos = round_up (rli->bitpos, type_align);
830 /* Offset so far becomes the position of this field after normalizing. */
832 DECL_FIELD_OFFSET (field) = rli->offset;
833 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
834 DECL_OFFSET_ALIGN (field) = rli->offset_align;
836 /* If this field ended up more aligned than we thought it would be (we
837 approximate this by seeing if its position changed), lay out the field
838 again; perhaps we can use an integral mode for it now. */
839 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
840 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
841 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
842 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
843 actual_align = BIGGEST_ALIGNMENT;
844 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
845 actual_align = (BITS_PER_UNIT
846 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
847 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
849 actual_align = DECL_OFFSET_ALIGN (field);
851 if (known_align != actual_align)
852 layout_decl (field, actual_align);
854 /* Now add size of this field to the size of the record. If the size is
855 not constant, treat the field as being a multiple of bytes and just
856 adjust the offset, resetting the bit position. Otherwise, apportion the
857 size amongst the bit position and offset. First handle the case of an
858 unspecified size, which can happen when we have an invalid nested struct
859 definition, such as struct j { struct j { int i; } }. The error message
860 is printed in finish_struct. */
861 if (DECL_SIZE (field) == 0)
863 else if (! TREE_CONSTANT (DECL_SIZE_UNIT (field)))
866 = size_binop (PLUS_EXPR, rli->offset,
868 size_binop (CEIL_DIV_EXPR, rli->bitpos,
869 bitsize_unit_node)));
871 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
872 rli->bitpos = bitsize_zero_node;
873 rli->offset_align = MIN (rli->offset_align, DECL_ALIGN (field));
877 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
882 /* Assuming that all the fields have been laid out, this function uses
883 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
884 inidicated by RLI. */
887 finalize_record_size (rli)
888 record_layout_info rli;
890 tree unpadded_size, unpadded_size_unit;
892 /* Now we want just byte and bit offsets, so set the offset alignment
893 to be a byte and then normalize. */
894 rli->offset_align = BITS_PER_UNIT;
897 /* Determine the desired alignment. */
898 #ifdef ROUND_TYPE_ALIGN
899 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
902 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
905 /* Compute the size so far. Be sure to allow for extra bits in the
906 size in bytes. We have guaranteed above that it will be no more
907 than a single byte. */
908 unpadded_size = rli_size_so_far (rli);
909 unpadded_size_unit = rli_size_unit_so_far (rli);
910 if (! integer_zerop (rli->bitpos))
912 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
914 /* Record the un-rounded size in the binfo node. But first we check
915 the size of TYPE_BINFO to make sure that BINFO_SIZE is available. */
916 if (TYPE_BINFO (rli->t) && TREE_VEC_LENGTH (TYPE_BINFO (rli->t)) > 6)
918 TYPE_BINFO_SIZE (rli->t) = unpadded_size;
919 TYPE_BINFO_SIZE_UNIT (rli->t) = unpadded_size_unit;
922 /* Round the size up to be a multiple of the required alignment */
923 #ifdef ROUND_TYPE_SIZE
924 TYPE_SIZE (rli->t) = ROUND_TYPE_SIZE (rli->t, unpadded_size,
925 TYPE_ALIGN (rli->t));
926 TYPE_SIZE_UNIT (rli->t)
927 = ROUND_TYPE_SIZE_UNIT (rli->t, unpaded_size_unit,
928 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
930 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
931 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
932 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
935 if (warn_padded && TREE_CONSTANT (unpadded_size)
936 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
937 warning ("padding struct size to alignment boundary");
939 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
940 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
941 && TREE_CONSTANT (unpadded_size))
945 #ifdef ROUND_TYPE_ALIGN
947 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
949 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
952 #ifdef ROUND_TYPE_SIZE
953 unpacked_size = ROUND_TYPE_SIZE (rli->t, TYPE_SIZE (rli->t),
954 rli->unpacked_align);
956 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
959 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
961 TYPE_PACKED (rli->t) = 0;
963 if (TYPE_NAME (rli->t))
967 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
968 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
970 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
972 if (STRICT_ALIGNMENT)
973 warning ("packed attribute causes inefficient alignment for `%s'", name);
975 warning ("packed attribute is unnecessary for `%s'", name);
979 if (STRICT_ALIGNMENT)
980 warning ("packed attribute causes inefficient alignment");
982 warning ("packed attribute is unnecessary");
988 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
991 compute_record_mode (type)
995 enum machine_mode mode = VOIDmode;
997 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
998 However, if possible, we use a mode that fits in a register
999 instead, in order to allow for better optimization down the
1001 TYPE_MODE (type) = BLKmode;
1003 if (! host_integerp (TYPE_SIZE (type), 1))
1006 /* A record which has any BLKmode members must itself be
1007 BLKmode; it can't go in a register. Unless the member is
1008 BLKmode only because it isn't aligned. */
1009 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1011 unsigned HOST_WIDE_INT bitpos;
1013 if (TREE_CODE (field) != FIELD_DECL)
1016 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1017 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1018 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
1019 || ! host_integerp (bit_position (field), 1)
1020 || ! host_integerp (DECL_SIZE (field), 1))
1023 bitpos = int_bit_position (field);
1025 /* Must be BLKmode if any field crosses a word boundary,
1026 since extract_bit_field can't handle that in registers. */
1027 if (bitpos / BITS_PER_WORD
1028 != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
1030 /* But there is no problem if the field is entire words. */
1031 && tree_low_cst (DECL_SIZE (field), 1) % BITS_PER_WORD != 0)
1034 /* If this field is the whole struct, remember its mode so
1035 that, say, we can put a double in a class into a DF
1036 register instead of forcing it to live in the stack. */
1037 if (field == TYPE_FIELDS (type) && TREE_CHAIN (field) == 0)
1038 mode = DECL_MODE (field);
1040 #ifdef STRUCT_FORCE_BLK
1041 /* With some targets, eg. c4x, it is sub-optimal
1042 to access an aligned BLKmode structure as a scalar. */
1043 if (mode == VOIDmode && STRUCT_FORCE_BLK (field))
1045 #endif /* STRUCT_FORCE_BLK */
1048 if (mode != VOIDmode)
1049 /* We only have one real field; use its mode. */
1050 TYPE_MODE (type) = mode;
1052 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1054 /* If structure's known alignment is less than what the scalar
1055 mode would need, and it matters, then stick with BLKmode. */
1056 if (TYPE_MODE (type) != BLKmode
1058 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1059 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1061 /* If this is the only reason this type is BLKmode, then
1062 don't force containing types to be BLKmode. */
1063 TYPE_NO_FORCE_BLK (type) = 1;
1064 TYPE_MODE (type) = BLKmode;
1068 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1072 finalize_type_size (type)
1075 /* Normally, use the alignment corresponding to the mode chosen.
1076 However, where strict alignment is not required, avoid
1077 over-aligning structures, since most compilers do not do this
1080 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1081 && (STRICT_ALIGNMENT
1082 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1083 && TREE_CODE (type) != QUAL_UNION_TYPE
1084 && TREE_CODE (type) != ARRAY_TYPE)))
1085 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1087 /* Do machine-dependent extra alignment. */
1088 #ifdef ROUND_TYPE_ALIGN
1090 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1093 /* If we failed to find a simple way to calculate the unit size
1094 of the type, find it by division. */
1095 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1096 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1097 result will fit in sizetype. We will get more efficient code using
1098 sizetype, so we force a conversion. */
1099 TYPE_SIZE_UNIT (type)
1100 = convert (sizetype,
1101 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1102 bitsize_unit_node));
1104 if (TYPE_SIZE (type) != 0)
1106 #ifdef ROUND_TYPE_SIZE
1108 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1109 TYPE_SIZE_UNIT (type)
1110 = ROUND_TYPE_SIZE_UNIT (type, TYPE_SIZE_UNIT (type),
1111 TYPE_ALIGN (type) / BITS_PER_UNIT);
1113 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1114 TYPE_SIZE_UNIT (type)
1115 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1119 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1120 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1121 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1122 if (TYPE_SIZE_UNIT (type) != 0
1123 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1124 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1126 /* Also layout any other variants of the type. */
1127 if (TYPE_NEXT_VARIANT (type)
1128 || type != TYPE_MAIN_VARIANT (type))
1131 /* Record layout info of this variant. */
1132 tree size = TYPE_SIZE (type);
1133 tree size_unit = TYPE_SIZE_UNIT (type);
1134 unsigned int align = TYPE_ALIGN (type);
1135 enum machine_mode mode = TYPE_MODE (type);
1137 /* Copy it into all variants. */
1138 for (variant = TYPE_MAIN_VARIANT (type);
1140 variant = TYPE_NEXT_VARIANT (variant))
1142 TYPE_SIZE (variant) = size;
1143 TYPE_SIZE_UNIT (variant) = size_unit;
1144 TYPE_ALIGN (variant) = align;
1145 TYPE_MODE (variant) = mode;
1150 /* Do all of the work required to layout the type indicated by RLI,
1151 once the fields have been laid out. This function will call `free'
1155 finish_record_layout (rli)
1156 record_layout_info rli;
1158 /* Compute the final size. */
1159 finalize_record_size (rli);
1161 /* Compute the TYPE_MODE for the record. */
1162 compute_record_mode (rli->t);
1164 /* Lay out any static members. This is done now because their type
1165 may use the record's type. */
1166 while (rli->pending_statics)
1168 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1169 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1172 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1173 finalize_type_size (rli->t);
1179 /* Calculate the mode, size, and alignment for TYPE.
1180 For an array type, calculate the element separation as well.
1181 Record TYPE on the chain of permanent or temporary types
1182 so that dbxout will find out about it.
1184 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1185 layout_type does nothing on such a type.
1187 If the type is incomplete, its TYPE_SIZE remains zero. */
1198 /* Do nothing if type has been laid out before. */
1199 if (TYPE_SIZE (type))
1202 /* Make sure all nodes we allocate are not momentary; they must last
1203 past the current statement. */
1204 old = suspend_momentary ();
1206 /* Put all our nodes into the same obstack as the type. Also,
1207 make expressions saveable (this is a no-op for permanent types). */
1209 push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type));
1210 saveable_allocation ();
1212 switch (TREE_CODE (type))
1215 /* This kind of type is the responsibility
1216 of the language-specific code. */
1219 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1220 if (TYPE_PRECISION (type) == 0)
1221 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1223 /* ... fall through ... */
1228 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1229 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1230 TREE_UNSIGNED (type) = 1;
1232 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1234 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1235 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1239 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1240 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1241 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1245 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1247 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1248 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1249 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1251 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1252 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1256 /* This is an incomplete type and so doesn't have a size. */
1257 TYPE_ALIGN (type) = 1;
1258 TYPE_MODE (type) = VOIDmode;
1262 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1263 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1264 TYPE_MODE (type) = ptr_mode;
1269 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1270 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1271 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1275 case REFERENCE_TYPE:
1276 TYPE_MODE (type) = ptr_mode;
1277 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1278 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1279 TREE_UNSIGNED (type) = 1;
1280 TYPE_PRECISION (type) = POINTER_SIZE;
1285 register tree index = TYPE_DOMAIN (type);
1286 register tree element = TREE_TYPE (type);
1288 build_pointer_type (element);
1290 /* We need to know both bounds in order to compute the size. */
1291 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1292 && TYPE_SIZE (element))
1294 tree ub = TYPE_MAX_VALUE (index);
1295 tree lb = TYPE_MIN_VALUE (index);
1299 /* If UB is max (lb - 1, x), remove the MAX_EXPR since the
1300 test for negative below covers it. */
1301 if (TREE_CODE (ub) == MAX_EXPR
1302 && TREE_CODE (TREE_OPERAND (ub, 0)) == MINUS_EXPR
1303 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 0), 1))
1304 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 0), 0),
1306 ub = TREE_OPERAND (ub, 1);
1307 else if (TREE_CODE (ub) == MAX_EXPR
1308 && TREE_CODE (TREE_OPERAND (ub, 1)) == MINUS_EXPR
1309 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 1), 1))
1310 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 1),
1313 ub = TREE_OPERAND (ub, 0);
1315 /* The initial subtraction should happen in the original type so
1316 that (possible) negative values are handled appropriately. */
1317 length = size_binop (PLUS_EXPR, size_one_node,
1319 fold (build (MINUS_EXPR,
1323 /* If neither bound is a constant and sizetype is signed, make
1324 sure the size is never negative. We should really do this
1325 if *either* bound is non-constant, but this is the best
1326 compromise between C and Ada. */
1327 if (! TREE_UNSIGNED (sizetype)
1328 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
1329 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
1330 length = size_binop (MAX_EXPR, length, size_zero_node);
1332 /* Special handling for arrays of bits (for Chill). */
1333 element_size = TYPE_SIZE (element);
1334 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element))
1336 HOST_WIDE_INT maxvalue
1337 = TREE_INT_CST_LOW (TYPE_MAX_VALUE (element));
1338 HOST_WIDE_INT minvalue
1339 = TREE_INT_CST_LOW (TYPE_MIN_VALUE (element));
1341 if (maxvalue - minvalue == 1
1342 && (maxvalue == 1 || maxvalue == 0))
1343 element_size = integer_one_node;
1346 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1347 convert (bitsizetype, length));
1349 /* If we know the size of the element, calculate the total
1350 size directly, rather than do some division thing below.
1351 This optimization helps Fortran assumed-size arrays
1352 (where the size of the array is determined at runtime)
1354 Note that we can't do this in the case where the size of
1355 the elements is one bit since TYPE_SIZE_UNIT cannot be
1356 set correctly in that case. */
1357 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1358 TYPE_SIZE_UNIT (type)
1359 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1362 /* Now round the alignment and size,
1363 using machine-dependent criteria if any. */
1365 #ifdef ROUND_TYPE_ALIGN
1367 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1369 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1372 #ifdef ROUND_TYPE_SIZE
1373 if (TYPE_SIZE (type) != 0)
1376 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1378 /* If the rounding changed the size of the type, remove any
1379 pre-calculated TYPE_SIZE_UNIT. */
1380 if (simple_cst_equal (TYPE_SIZE (type), tmp) != 1)
1381 TYPE_SIZE_UNIT (type) = NULL;
1383 TYPE_SIZE (type) = tmp;
1387 TYPE_MODE (type) = BLKmode;
1388 if (TYPE_SIZE (type) != 0
1389 /* BLKmode elements force BLKmode aggregate;
1390 else extract/store fields may lose. */
1391 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1392 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1395 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1397 if (TYPE_MODE (type) != BLKmode
1398 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1399 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1400 && TYPE_MODE (type) != BLKmode)
1402 TYPE_NO_FORCE_BLK (type) = 1;
1403 TYPE_MODE (type) = BLKmode;
1411 case QUAL_UNION_TYPE:
1414 record_layout_info rli;
1416 /* Initialize the layout information. */
1417 rli = start_record_layout (type);
1419 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1420 in the reverse order in building the COND_EXPR that denotes
1421 its size. We reverse them again later. */
1422 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1423 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1425 /* Place all the fields. */
1426 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1427 place_field (rli, field);
1429 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1430 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1432 /* Finish laying out the record. */
1433 finish_record_layout (rli);
1437 case SET_TYPE: /* Used by Chill and Pascal. */
1438 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1439 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1443 #ifndef SET_WORD_SIZE
1444 #define SET_WORD_SIZE BITS_PER_WORD
1446 unsigned int alignment
1447 = set_alignment ? set_alignment : SET_WORD_SIZE;
1449 = (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
1450 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1);
1452 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1454 if (rounded_size > (int) alignment)
1455 TYPE_MODE (type) = BLKmode;
1457 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1459 TYPE_SIZE (type) = bitsize_int (rounded_size);
1460 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1461 TYPE_ALIGN (type) = alignment;
1462 TYPE_PRECISION (type) = size_in_bits;
1467 /* The size may vary in different languages, so the language front end
1468 should fill in the size. */
1469 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1470 TYPE_MODE (type) = BLKmode;
1477 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1478 records and unions, finish_record_layout already called this
1480 if (TREE_CODE (type) != RECORD_TYPE
1481 && TREE_CODE (type) != UNION_TYPE
1482 && TREE_CODE (type) != QUAL_UNION_TYPE)
1483 finalize_type_size (type);
1486 resume_momentary (old);
1488 /* If this type is created before sizetype has been permanently set,
1489 record it so set_sizetype can fix it up. */
1491 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1494 /* Create and return a type for signed integers of PRECISION bits. */
1497 make_signed_type (precision)
1500 register tree type = make_node (INTEGER_TYPE);
1502 TYPE_PRECISION (type) = precision;
1504 fixup_signed_type (type);
1508 /* Create and return a type for unsigned integers of PRECISION bits. */
1511 make_unsigned_type (precision)
1514 register tree type = make_node (INTEGER_TYPE);
1516 TYPE_PRECISION (type) = precision;
1518 fixup_unsigned_type (type);
1522 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1523 value to enable integer types to be created. */
1526 initialize_sizetypes ()
1528 tree t = make_node (INTEGER_TYPE);
1530 /* Set this so we do something reasonable for the build_int_2 calls
1532 integer_type_node = t;
1534 TYPE_MODE (t) = SImode;
1535 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1536 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1537 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1538 TREE_UNSIGNED (t) = 1;
1539 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1540 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1541 TYPE_IS_SIZETYPE (t) = 1;
1543 /* 1000 avoids problems with possible overflow and is certainly
1544 larger than any size value we'd want to be storing. */
1545 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1547 /* These two must be different nodes because of the caching done in
1550 bitsizetype = copy_node (t);
1551 integer_type_node = 0;
1554 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1555 Also update the type of any standard type's sizes made so far. */
1561 int oprecision = TYPE_PRECISION (type);
1562 /* The *bitsizetype types use a precision that avoids overflows when
1563 calculating signed sizes / offsets in bits. However, when
1564 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1566 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1567 2 * HOST_BITS_PER_WIDE_INT);
1574 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1575 sizetype = copy_node (type);
1576 TYPE_DOMAIN (sizetype) = type;
1577 TYPE_IS_SIZETYPE (sizetype) = 1;
1578 bitsizetype = make_node (INTEGER_TYPE);
1579 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1580 TYPE_PRECISION (bitsizetype) = precision;
1581 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1583 if (TREE_UNSIGNED (type))
1584 fixup_unsigned_type (bitsizetype);
1586 fixup_signed_type (bitsizetype);
1588 layout_type (bitsizetype);
1590 if (TREE_UNSIGNED (type))
1592 usizetype = sizetype;
1593 ubitsizetype = bitsizetype;
1594 ssizetype = copy_node (make_signed_type (oprecision));
1595 sbitsizetype = copy_node (make_signed_type (precision));
1599 ssizetype = sizetype;
1600 sbitsizetype = bitsizetype;
1601 usizetype = copy_node (make_unsigned_type (oprecision));
1602 ubitsizetype = copy_node (make_unsigned_type (precision));
1605 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1607 /* Show is a sizetype, is a main type, and has no pointers to it. */
1608 for (i = 0; i < sizeof sizetype_tab / sizeof sizetype_tab[0]; i++)
1610 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1611 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1612 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1613 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1614 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1617 ggc_add_tree_root ((tree *) &sizetype_tab,
1618 sizeof sizetype_tab / sizeof (tree));
1620 /* Go down each of the types we already made and set the proper type
1621 for the sizes in them. */
1622 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1624 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE)
1627 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1628 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1631 early_type_list = 0;
1635 /* Set the extreme values of TYPE based on its precision in bits,
1636 then lay it out. Used when make_signed_type won't do
1637 because the tree code is not INTEGER_TYPE.
1638 E.g. for Pascal, when the -fsigned-char option is given. */
1641 fixup_signed_type (type)
1644 register int precision = TYPE_PRECISION (type);
1646 TYPE_MIN_VALUE (type)
1647 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1648 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1649 (((HOST_WIDE_INT) (-1)
1650 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1651 ? precision - HOST_BITS_PER_WIDE_INT - 1
1653 TYPE_MAX_VALUE (type)
1654 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1655 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1656 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1657 ? (((HOST_WIDE_INT) 1
1658 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1661 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1662 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1664 /* Lay out the type: set its alignment, size, etc. */
1668 /* Set the extreme values of TYPE based on its precision in bits,
1669 then lay it out. This is used both in `make_unsigned_type'
1670 and for enumeral types. */
1673 fixup_unsigned_type (type)
1676 register int precision = TYPE_PRECISION (type);
1678 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
1679 TYPE_MAX_VALUE (type)
1680 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1681 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1682 precision - HOST_BITS_PER_WIDE_INT > 0
1683 ? ((unsigned HOST_WIDE_INT) ~0
1684 >> (HOST_BITS_PER_WIDE_INT
1685 - (precision - HOST_BITS_PER_WIDE_INT)))
1687 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
1688 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
1690 /* Lay out the type: set its alignment, size, etc. */
1694 /* Find the best machine mode to use when referencing a bit field of length
1695 BITSIZE bits starting at BITPOS.
1697 The underlying object is known to be aligned to a boundary of ALIGN bits.
1698 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1699 larger than LARGEST_MODE (usually SImode).
1701 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1702 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1703 mode meeting these conditions.
1705 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1706 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1707 all the conditions. */
1710 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
1711 int bitsize, bitpos;
1713 enum machine_mode largest_mode;
1716 enum machine_mode mode;
1717 unsigned int unit = 0;
1719 /* Find the narrowest integer mode that contains the bit field. */
1720 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
1721 mode = GET_MODE_WIDER_MODE (mode))
1723 unit = GET_MODE_BITSIZE (mode);
1724 if ((bitpos % unit) + bitsize <= unit)
1728 if (mode == VOIDmode
1729 /* It is tempting to omit the following line
1730 if STRICT_ALIGNMENT is true.
1731 But that is incorrect, since if the bitfield uses part of 3 bytes
1732 and we use a 4-byte mode, we could get a spurious segv
1733 if the extra 4th byte is past the end of memory.
1734 (Though at least one Unix compiler ignores this problem:
1735 that on the Sequent 386 machine. */
1736 || MIN (unit, BIGGEST_ALIGNMENT) > align
1737 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
1740 if (SLOW_BYTE_ACCESS && ! volatilep)
1742 enum machine_mode wide_mode = VOIDmode, tmode;
1744 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
1745 tmode = GET_MODE_WIDER_MODE (tmode))
1747 unit = GET_MODE_BITSIZE (tmode);
1748 if (bitpos / unit == (bitpos + bitsize - 1) / unit
1749 && unit <= BITS_PER_WORD
1750 && unit <= MIN (align, BIGGEST_ALIGNMENT)
1751 && (largest_mode == VOIDmode
1752 || unit <= GET_MODE_BITSIZE (largest_mode)))
1756 if (wide_mode != VOIDmode)
1763 /* Return the alignment of MODE. This will be bounded by 1 and
1764 BIGGEST_ALIGNMENT. */
1767 get_mode_alignment (mode)
1768 enum machine_mode mode;
1770 unsigned int alignment = GET_MODE_UNIT_SIZE (mode) * BITS_PER_UNIT;
1772 /* Extract the LSB of the size. */
1773 alignment = alignment & -alignment;
1775 alignment = MIN (BIGGEST_ALIGNMENT, MAX (1, alignment));
1779 /* This function is run once to initialize stor-layout.c. */
1782 init_stor_layout_once ()
1784 ggc_add_tree_root (&pending_sizes, 1);