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, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
36 #include "langhooks.h"
38 /* Set to one when set_sizetype has been called. */
39 static int sizetype_set;
41 /* List of types created before set_sizetype has been called. We do not
42 make this a GGC root since we want these nodes to be reclaimed. */
43 static tree early_type_list;
45 /* Data type for the expressions representing sizes of data types.
46 It is the first integer type laid out. */
47 tree sizetype_tab[(int) TYPE_KIND_LAST];
49 /* If nonzero, this is an upper limit on alignment of structure fields.
50 The value is measured in bits. */
51 unsigned int maximum_field_alignment;
53 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
54 May be overridden by front-ends. */
55 unsigned int set_alignment = 0;
57 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
58 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
59 called only by a front end. */
60 static int reference_types_internal = 0;
62 static void finalize_record_size (record_layout_info);
63 static void finalize_type_size (tree);
64 static void place_union_field (record_layout_info, tree);
65 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
66 static int excess_unit_span (HOST_WIDE_INT, HOST_WIDE_INT, HOST_WIDE_INT,
69 extern void debug_rli (record_layout_info);
71 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
73 static GTY(()) tree pending_sizes;
75 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
79 internal_reference_types (void)
81 reference_types_internal = 1;
84 /* Get a list of all the objects put on the pending sizes list. */
87 get_pending_sizes (void)
89 tree chain = pending_sizes;
95 /* Add EXPR to the pending sizes list. */
98 put_pending_size (tree expr)
100 /* Strip any simple arithmetic from EXPR to see if it has an underlying
102 expr = skip_simple_arithmetic (expr);
104 if (TREE_CODE (expr) == SAVE_EXPR)
105 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
108 /* Put a chain of objects into the pending sizes list, which must be
112 put_pending_sizes (tree chain)
117 pending_sizes = chain;
120 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
121 to serve as the actual size-expression for a type or decl. */
124 variable_size (tree size)
128 /* If the language-processor is to take responsibility for variable-sized
129 items (e.g., languages which have elaboration procedures like Ada),
130 just return SIZE unchanged. Likewise for self-referential sizes and
132 if (TREE_CONSTANT (size)
133 || lang_hooks.decls.global_bindings_p () < 0
134 || CONTAINS_PLACEHOLDER_P (size))
137 size = save_expr (size);
139 /* If an array with a variable number of elements is declared, and
140 the elements require destruction, we will emit a cleanup for the
141 array. That cleanup is run both on normal exit from the block
142 and in the exception-handler for the block. Normally, when code
143 is used in both ordinary code and in an exception handler it is
144 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
145 not wish to do that here; the array-size is the same in both
147 save = skip_simple_arithmetic (size);
149 if (cfun && cfun->x_dont_save_pending_sizes_p)
150 /* The front-end doesn't want us to keep a list of the expressions
151 that determine sizes for variable size objects. Trust it. */
154 if (lang_hooks.decls.global_bindings_p ())
156 if (TREE_CONSTANT (size))
157 error ("type size can't be explicitly evaluated");
159 error ("variable-size type declared outside of any function");
161 return size_one_node;
164 put_pending_size (save);
169 #ifndef MAX_FIXED_MODE_SIZE
170 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
173 /* Return the machine mode to use for a nonscalar of SIZE bits. The
174 mode must be in class CLASS, and have exactly that many value bits;
175 it may have padding as well. If LIMIT is nonzero, modes of wider
176 than MAX_FIXED_MODE_SIZE will not be used. */
179 mode_for_size (unsigned int size, enum mode_class class, int limit)
181 enum machine_mode mode;
183 if (limit && size > MAX_FIXED_MODE_SIZE)
186 /* Get the first mode which has this size, in the specified class. */
187 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
188 mode = GET_MODE_WIDER_MODE (mode))
189 if (GET_MODE_PRECISION (mode) == size)
195 /* Similar, except passed a tree node. */
198 mode_for_size_tree (tree size, enum mode_class class, int limit)
200 if (TREE_CODE (size) != INTEGER_CST
201 || TREE_OVERFLOW (size)
202 /* What we really want to say here is that the size can fit in a
203 host integer, but we know there's no way we'd find a mode for
204 this many bits, so there's no point in doing the precise test. */
205 || compare_tree_int (size, 1000) > 0)
208 return mode_for_size (tree_low_cst (size, 1), class, limit);
211 /* Similar, but never return BLKmode; return the narrowest mode that
212 contains at least the requested number of value bits. */
215 smallest_mode_for_size (unsigned int size, enum mode_class class)
217 enum machine_mode mode;
219 /* Get the first mode which has at least this size, in the
221 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
222 mode = GET_MODE_WIDER_MODE (mode))
223 if (GET_MODE_PRECISION (mode) >= size)
229 /* Find an integer mode of the exact same size, or BLKmode on failure. */
232 int_mode_for_mode (enum machine_mode mode)
234 switch (GET_MODE_CLASS (mode))
237 case MODE_PARTIAL_INT:
240 case MODE_COMPLEX_INT:
241 case MODE_COMPLEX_FLOAT:
243 case MODE_VECTOR_INT:
244 case MODE_VECTOR_FLOAT:
245 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
252 /* ... fall through ... */
262 /* Return the alignment of MODE. This will be bounded by 1 and
263 BIGGEST_ALIGNMENT. */
266 get_mode_alignment (enum machine_mode mode)
268 return MIN (BIGGEST_ALIGNMENT, MAX (1, mode_base_align[mode]*BITS_PER_UNIT));
271 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
272 This can only be applied to objects of a sizetype. */
275 round_up (tree value, int divisor)
279 /* If divisor is a power of two, simplify this to bit manipulation. */
280 if (divisor == (divisor & -divisor))
282 t = size_int_type (divisor - 1, TREE_TYPE (value));
283 value = size_binop (PLUS_EXPR, value, t);
284 t = size_int_type (-divisor, TREE_TYPE (value));
285 value = size_binop (BIT_AND_EXPR, value, t);
289 t = size_int_type (divisor, TREE_TYPE (value));
290 value = size_binop (CEIL_DIV_EXPR, value, t);
291 value = size_binop (MULT_EXPR, value, t);
297 /* Likewise, but round down. */
300 round_down (tree value, int divisor)
304 /* If divisor is a power of two, simplify this to bit manipulation. */
305 if (divisor == (divisor & -divisor))
307 t = size_int_type (-divisor, TREE_TYPE (value));
308 value = size_binop (BIT_AND_EXPR, value, t);
312 t = size_int_type (divisor, TREE_TYPE (value));
313 value = size_binop (FLOOR_DIV_EXPR, value, t);
314 value = size_binop (MULT_EXPR, value, t);
320 /* Subroutine of layout_decl: Force alignment required for the data type.
321 But if the decl itself wants greater alignment, don't override that. */
324 do_type_align (tree type, tree decl)
326 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
328 DECL_ALIGN (decl) = TYPE_ALIGN (type);
329 if (TREE_CODE (decl) == FIELD_DECL)
330 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
334 /* Set the size, mode and alignment of a ..._DECL node.
335 TYPE_DECL does need this for C++.
336 Note that LABEL_DECL and CONST_DECL nodes do not need this,
337 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
338 Don't call layout_decl for them.
340 KNOWN_ALIGN is the amount of alignment we can assume this
341 decl has with no special effort. It is relevant only for FIELD_DECLs
342 and depends on the previous fields.
343 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
344 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
345 the record will be aligned to suit. */
348 layout_decl (tree decl, unsigned int known_align)
350 tree type = TREE_TYPE (decl);
351 enum tree_code code = TREE_CODE (decl);
354 if (code == CONST_DECL)
356 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
357 && code != TYPE_DECL && code != FIELD_DECL)
360 rtl = DECL_RTL_IF_SET (decl);
362 if (type == error_mark_node)
363 type = void_type_node;
365 /* Usually the size and mode come from the data type without change,
366 however, the front-end may set the explicit width of the field, so its
367 size may not be the same as the size of its type. This happens with
368 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
369 also happens with other fields. For example, the C++ front-end creates
370 zero-sized fields corresponding to empty base classes, and depends on
371 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
372 size in bytes from the size in bits. If we have already set the mode,
373 don't set it again since we can be called twice for FIELD_DECLs. */
375 DECL_UNSIGNED (decl) = TYPE_UNSIGNED (type);
376 if (DECL_MODE (decl) == VOIDmode)
377 DECL_MODE (decl) = TYPE_MODE (type);
379 if (DECL_SIZE (decl) == 0)
381 DECL_SIZE (decl) = TYPE_SIZE (type);
382 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
384 else if (DECL_SIZE_UNIT (decl) == 0)
385 DECL_SIZE_UNIT (decl)
386 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
389 if (code != FIELD_DECL)
390 /* For non-fields, update the alignment from the type. */
391 do_type_align (type, decl);
393 /* For fields, it's a bit more complicated... */
395 bool old_user_align = DECL_USER_ALIGN (decl);
397 if (DECL_BIT_FIELD (decl))
399 DECL_BIT_FIELD_TYPE (decl) = type;
401 /* A zero-length bit-field affects the alignment of the next
403 if (integer_zerop (DECL_SIZE (decl))
404 && ! DECL_PACKED (decl)
405 && ! targetm.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl)))
407 #ifdef PCC_BITFIELD_TYPE_MATTERS
408 if (PCC_BITFIELD_TYPE_MATTERS)
409 do_type_align (type, decl);
413 #ifdef EMPTY_FIELD_BOUNDARY
414 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
416 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
417 DECL_USER_ALIGN (decl) = 0;
423 /* See if we can use an ordinary integer mode for a bit-field.
424 Conditions are: a fixed size that is correct for another mode
425 and occupying a complete byte or bytes on proper boundary. */
426 if (TYPE_SIZE (type) != 0
427 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
428 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
430 enum machine_mode xmode
431 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
435 || known_align >= GET_MODE_ALIGNMENT (xmode)))
437 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
439 DECL_MODE (decl) = xmode;
440 DECL_BIT_FIELD (decl) = 0;
444 /* Turn off DECL_BIT_FIELD if we won't need it set. */
445 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
446 && known_align >= TYPE_ALIGN (type)
447 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
448 DECL_BIT_FIELD (decl) = 0;
450 else if (DECL_PACKED (decl) && DECL_USER_ALIGN (decl))
451 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
452 round up; we'll reduce it again below. We want packing to
453 supersede USER_ALIGN inherited from the type, but defer to
454 alignment explicitly specified on the field decl. */;
456 do_type_align (type, decl);
458 /* If the field is of variable size, we can't misalign it since we
459 have no way to make a temporary to align the result. But this
460 isn't an issue if the decl is not addressable. Likewise if it
463 Note that do_type_align may set DECL_USER_ALIGN, so we need to
464 check old_user_align instead. */
465 if (DECL_PACKED (decl)
467 && (DECL_NONADDRESSABLE_P (decl)
468 || DECL_SIZE_UNIT (decl) == 0
469 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
470 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
472 if (! DECL_USER_ALIGN (decl) && ! DECL_PACKED (decl))
474 /* Some targets (i.e. i386, VMS) limit struct field alignment
475 to a lower boundary than alignment of variables unless
476 it was overridden by attribute aligned. */
477 #ifdef BIGGEST_FIELD_ALIGNMENT
479 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
481 #ifdef ADJUST_FIELD_ALIGN
482 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
486 /* Should this be controlled by DECL_USER_ALIGN, too? */
487 if (maximum_field_alignment != 0)
488 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
491 /* Evaluate nonconstant size only once, either now or as soon as safe. */
492 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
493 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
494 if (DECL_SIZE_UNIT (decl) != 0
495 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
496 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
498 /* If requested, warn about definitions of large data objects. */
500 && (code == VAR_DECL || code == PARM_DECL)
501 && ! DECL_EXTERNAL (decl))
503 tree size = DECL_SIZE_UNIT (decl);
505 if (size != 0 && TREE_CODE (size) == INTEGER_CST
506 && compare_tree_int (size, larger_than_size) > 0)
508 int size_as_int = TREE_INT_CST_LOW (size);
510 if (compare_tree_int (size, size_as_int) == 0)
511 warning ("%Jsize of '%D' is %d bytes", decl, decl, size_as_int);
513 warning ("%Jsize of '%D' is larger than %d bytes",
514 decl, decl, larger_than_size);
518 /* If the RTL was already set, update its mode and mem attributes. */
521 PUT_MODE (rtl, DECL_MODE (decl));
522 SET_DECL_RTL (decl, 0);
523 set_mem_attributes (rtl, decl, 1);
524 SET_DECL_RTL (decl, rtl);
528 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
529 a previous call to layout_decl and calls it again. */
532 relayout_decl (tree decl)
534 DECL_SIZE (decl) = DECL_SIZE_UNIT (decl) = 0;
535 DECL_MODE (decl) = VOIDmode;
536 DECL_ALIGN (decl) = 0;
537 SET_DECL_RTL (decl, 0);
539 layout_decl (decl, 0);
542 /* Hook for a front-end function that can modify the record layout as needed
543 immediately before it is finalized. */
545 void (*lang_adjust_rli) (record_layout_info) = 0;
548 set_lang_adjust_rli (void (*f) (record_layout_info))
553 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
554 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
555 is to be passed to all other layout functions for this record. It is the
556 responsibility of the caller to call `free' for the storage returned.
557 Note that garbage collection is not permitted until we finish laying
561 start_record_layout (tree t)
563 record_layout_info rli = xmalloc (sizeof (struct record_layout_info_s));
567 /* If the type has a minimum specified alignment (via an attribute
568 declaration, for example) use it -- otherwise, start with a
569 one-byte alignment. */
570 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
571 rli->unpacked_align = rli->record_align;
572 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
574 #ifdef STRUCTURE_SIZE_BOUNDARY
575 /* Packed structures don't need to have minimum size. */
576 if (! TYPE_PACKED (t))
577 rli->record_align = MAX (rli->record_align, (unsigned) STRUCTURE_SIZE_BOUNDARY);
580 rli->offset = size_zero_node;
581 rli->bitpos = bitsize_zero_node;
583 rli->pending_statics = 0;
584 rli->packed_maybe_necessary = 0;
589 /* These four routines perform computations that convert between
590 the offset/bitpos forms and byte and bit offsets. */
593 bit_from_pos (tree offset, tree bitpos)
595 return size_binop (PLUS_EXPR, bitpos,
596 size_binop (MULT_EXPR, convert (bitsizetype, offset),
601 byte_from_pos (tree offset, tree bitpos)
603 return size_binop (PLUS_EXPR, offset,
605 size_binop (TRUNC_DIV_EXPR, bitpos,
606 bitsize_unit_node)));
610 pos_from_bit (tree *poffset, tree *pbitpos, unsigned int off_align,
613 *poffset = size_binop (MULT_EXPR,
615 size_binop (FLOOR_DIV_EXPR, pos,
616 bitsize_int (off_align))),
617 size_int (off_align / BITS_PER_UNIT));
618 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
621 /* Given a pointer to bit and byte offsets and an offset alignment,
622 normalize the offsets so they are within the alignment. */
625 normalize_offset (tree *poffset, tree *pbitpos, unsigned int off_align)
627 /* If the bit position is now larger than it should be, adjust it
629 if (compare_tree_int (*pbitpos, off_align) >= 0)
631 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
632 bitsize_int (off_align));
635 = size_binop (PLUS_EXPR, *poffset,
636 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
637 size_int (off_align / BITS_PER_UNIT)));
640 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
644 /* Print debugging information about the information in RLI. */
647 debug_rli (record_layout_info rli)
649 print_node_brief (stderr, "type", rli->t, 0);
650 print_node_brief (stderr, "\noffset", rli->offset, 0);
651 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
653 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
654 rli->record_align, rli->unpacked_align,
656 if (rli->packed_maybe_necessary)
657 fprintf (stderr, "packed may be necessary\n");
659 if (rli->pending_statics)
661 fprintf (stderr, "pending statics:\n");
662 debug_tree (rli->pending_statics);
666 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
667 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
670 normalize_rli (record_layout_info rli)
672 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
675 /* Returns the size in bytes allocated so far. */
678 rli_size_unit_so_far (record_layout_info rli)
680 return byte_from_pos (rli->offset, rli->bitpos);
683 /* Returns the size in bits allocated so far. */
686 rli_size_so_far (record_layout_info rli)
688 return bit_from_pos (rli->offset, rli->bitpos);
691 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
692 the next available location is given by KNOWN_ALIGN. Update the
693 variable alignment fields in RLI, and return the alignment to give
697 update_alignment_for_field (record_layout_info rli, tree field,
698 unsigned int known_align)
700 /* The alignment required for FIELD. */
701 unsigned int desired_align;
702 /* The type of this field. */
703 tree type = TREE_TYPE (field);
704 /* True if the field was explicitly aligned by the user. */
708 /* Lay out the field so we know what alignment it needs. */
709 layout_decl (field, known_align);
710 desired_align = DECL_ALIGN (field);
711 user_align = DECL_USER_ALIGN (field);
713 is_bitfield = (type != error_mark_node
714 && DECL_BIT_FIELD_TYPE (field)
715 && ! integer_zerop (TYPE_SIZE (type)));
717 /* Record must have at least as much alignment as any field.
718 Otherwise, the alignment of the field within the record is
720 if (is_bitfield && targetm.ms_bitfield_layout_p (rli->t))
722 /* Here, the alignment of the underlying type of a bitfield can
723 affect the alignment of a record; even a zero-sized field
724 can do this. The alignment should be to the alignment of
725 the type, except that for zero-size bitfields this only
726 applies if there was an immediately prior, nonzero-size
727 bitfield. (That's the way it is, experimentally.) */
728 if (! integer_zerop (DECL_SIZE (field))
729 ? ! DECL_PACKED (field)
731 && DECL_BIT_FIELD_TYPE (rli->prev_field)
732 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
734 unsigned int type_align = TYPE_ALIGN (type);
735 type_align = MAX (type_align, desired_align);
736 if (maximum_field_alignment != 0)
737 type_align = MIN (type_align, maximum_field_alignment);
738 rli->record_align = MAX (rli->record_align, type_align);
739 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
742 #ifdef PCC_BITFIELD_TYPE_MATTERS
743 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
745 /* Named bit-fields cause the entire structure to have the
746 alignment implied by their type. Some targets also apply the same
747 rules to unnamed bitfields. */
748 if (DECL_NAME (field) != 0
749 || targetm.align_anon_bitfield ())
751 unsigned int type_align = TYPE_ALIGN (type);
753 #ifdef ADJUST_FIELD_ALIGN
754 if (! TYPE_USER_ALIGN (type))
755 type_align = ADJUST_FIELD_ALIGN (field, type_align);
758 if (maximum_field_alignment != 0)
759 type_align = MIN (type_align, maximum_field_alignment);
760 else if (DECL_PACKED (field))
761 type_align = MIN (type_align, BITS_PER_UNIT);
763 /* The alignment of the record is increased to the maximum
764 of the current alignment, the alignment indicated on the
765 field (i.e., the alignment specified by an __aligned__
766 attribute), and the alignment indicated by the type of
768 rli->record_align = MAX (rli->record_align, desired_align);
769 rli->record_align = MAX (rli->record_align, type_align);
772 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
773 user_align |= TYPE_USER_ALIGN (type);
779 rli->record_align = MAX (rli->record_align, desired_align);
780 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
783 TYPE_USER_ALIGN (rli->t) |= user_align;
785 return desired_align;
788 /* Called from place_field to handle unions. */
791 place_union_field (record_layout_info rli, tree field)
793 update_alignment_for_field (rli, field, /*known_align=*/0);
795 DECL_FIELD_OFFSET (field) = size_zero_node;
796 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
797 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
799 /* We assume the union's size will be a multiple of a byte so we don't
800 bother with BITPOS. */
801 if (TREE_CODE (rli->t) == UNION_TYPE)
802 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
803 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
804 rli->offset = fold (build (COND_EXPR, sizetype,
805 DECL_QUALIFIER (field),
806 DECL_SIZE_UNIT (field), rli->offset));
809 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
810 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
811 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
812 units of alignment than the underlying TYPE. */
814 excess_unit_span (HOST_WIDE_INT byte_offset, HOST_WIDE_INT bit_offset,
815 HOST_WIDE_INT size, HOST_WIDE_INT align, tree type)
817 /* Note that the calculation of OFFSET might overflow; we calculate it so
818 that we still get the right result as long as ALIGN is a power of two. */
819 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
821 offset = offset % align;
822 return ((offset + size + align - 1) / align
823 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
828 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
829 is a FIELD_DECL to be added after those fields already present in
830 T. (FIELD is not actually added to the TYPE_FIELDS list here;
831 callers that desire that behavior must manually perform that step.) */
834 place_field (record_layout_info rli, tree field)
836 /* The alignment required for FIELD. */
837 unsigned int desired_align;
838 /* The alignment FIELD would have if we just dropped it into the
839 record as it presently stands. */
840 unsigned int known_align;
841 unsigned int actual_align;
842 /* The type of this field. */
843 tree type = TREE_TYPE (field);
845 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
848 /* If FIELD is static, then treat it like a separate variable, not
849 really like a structure field. If it is a FUNCTION_DECL, it's a
850 method. In both cases, all we do is lay out the decl, and we do
851 it *after* the record is laid out. */
852 if (TREE_CODE (field) == VAR_DECL)
854 rli->pending_statics = tree_cons (NULL_TREE, field,
855 rli->pending_statics);
859 /* Enumerators and enum types which are local to this class need not
860 be laid out. Likewise for initialized constant fields. */
861 else if (TREE_CODE (field) != FIELD_DECL)
864 /* Unions are laid out very differently than records, so split
865 that code off to another function. */
866 else if (TREE_CODE (rli->t) != RECORD_TYPE)
868 place_union_field (rli, field);
872 /* Work out the known alignment so far. Note that A & (-A) is the
873 value of the least-significant bit in A that is one. */
874 if (! integer_zerop (rli->bitpos))
875 known_align = (tree_low_cst (rli->bitpos, 1)
876 & - tree_low_cst (rli->bitpos, 1));
877 else if (integer_zerop (rli->offset))
878 known_align = BIGGEST_ALIGNMENT;
879 else if (host_integerp (rli->offset, 1))
880 known_align = (BITS_PER_UNIT
881 * (tree_low_cst (rli->offset, 1)
882 & - tree_low_cst (rli->offset, 1)));
884 known_align = rli->offset_align;
886 desired_align = update_alignment_for_field (rli, field, known_align);
888 if (warn_packed && DECL_PACKED (field))
890 if (known_align >= TYPE_ALIGN (type))
892 if (TYPE_ALIGN (type) > desired_align)
894 if (STRICT_ALIGNMENT)
895 warning ("%Jpacked attribute causes inefficient alignment "
896 "for '%D'", field, field);
898 warning ("%Jpacked attribute is unnecessary for '%D'",
903 rli->packed_maybe_necessary = 1;
906 /* Does this field automatically have alignment it needs by virtue
907 of the fields that precede it and the record's own alignment? */
908 if (known_align < desired_align)
910 /* No, we need to skip space before this field.
911 Bump the cumulative size to multiple of field alignment. */
914 warning ("%Jpadding struct to align '%D'", field, field);
916 /* If the alignment is still within offset_align, just align
918 if (desired_align < rli->offset_align)
919 rli->bitpos = round_up (rli->bitpos, desired_align);
922 /* First adjust OFFSET by the partial bits, then align. */
924 = size_binop (PLUS_EXPR, rli->offset,
926 size_binop (CEIL_DIV_EXPR, rli->bitpos,
927 bitsize_unit_node)));
928 rli->bitpos = bitsize_zero_node;
930 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
933 if (! TREE_CONSTANT (rli->offset))
934 rli->offset_align = desired_align;
938 /* Handle compatibility with PCC. Note that if the record has any
939 variable-sized fields, we need not worry about compatibility. */
940 #ifdef PCC_BITFIELD_TYPE_MATTERS
941 if (PCC_BITFIELD_TYPE_MATTERS
942 && ! targetm.ms_bitfield_layout_p (rli->t)
943 && TREE_CODE (field) == FIELD_DECL
944 && type != error_mark_node
945 && DECL_BIT_FIELD (field)
946 && ! DECL_PACKED (field)
947 && maximum_field_alignment == 0
948 && ! integer_zerop (DECL_SIZE (field))
949 && host_integerp (DECL_SIZE (field), 1)
950 && host_integerp (rli->offset, 1)
951 && host_integerp (TYPE_SIZE (type), 1))
953 unsigned int type_align = TYPE_ALIGN (type);
954 tree dsize = DECL_SIZE (field);
955 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
956 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
957 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
959 #ifdef ADJUST_FIELD_ALIGN
960 if (! TYPE_USER_ALIGN (type))
961 type_align = ADJUST_FIELD_ALIGN (field, type_align);
964 /* A bit field may not span more units of alignment of its type
965 than its type itself. Advance to next boundary if necessary. */
966 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
967 rli->bitpos = round_up (rli->bitpos, type_align);
969 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
973 #ifdef BITFIELD_NBYTES_LIMITED
974 if (BITFIELD_NBYTES_LIMITED
975 && ! targetm.ms_bitfield_layout_p (rli->t)
976 && TREE_CODE (field) == FIELD_DECL
977 && type != error_mark_node
978 && DECL_BIT_FIELD_TYPE (field)
979 && ! DECL_PACKED (field)
980 && ! integer_zerop (DECL_SIZE (field))
981 && host_integerp (DECL_SIZE (field), 1)
982 && host_integerp (rli->offset, 1)
983 && host_integerp (TYPE_SIZE (type), 1))
985 unsigned int type_align = TYPE_ALIGN (type);
986 tree dsize = DECL_SIZE (field);
987 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
988 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
989 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
991 #ifdef ADJUST_FIELD_ALIGN
992 if (! TYPE_USER_ALIGN (type))
993 type_align = ADJUST_FIELD_ALIGN (field, type_align);
996 if (maximum_field_alignment != 0)
997 type_align = MIN (type_align, maximum_field_alignment);
998 /* ??? This test is opposite the test in the containing if
999 statement, so this code is unreachable currently. */
1000 else if (DECL_PACKED (field))
1001 type_align = MIN (type_align, BITS_PER_UNIT);
1003 /* A bit field may not span the unit of alignment of its type.
1004 Advance to next boundary if necessary. */
1005 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
1006 rli->bitpos = round_up (rli->bitpos, type_align);
1008 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
1012 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1014 When a bit field is inserted into a packed record, the whole
1015 size of the underlying type is used by one or more same-size
1016 adjacent bitfields. (That is, if its long:3, 32 bits is
1017 used in the record, and any additional adjacent long bitfields are
1018 packed into the same chunk of 32 bits. However, if the size
1019 changes, a new field of that size is allocated.) In an unpacked
1020 record, this is the same as using alignment, but not equivalent
1023 Note: for compatibility, we use the type size, not the type alignment
1024 to determine alignment, since that matches the documentation */
1026 if (targetm.ms_bitfield_layout_p (rli->t)
1027 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1028 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1030 /* At this point, either the prior or current are bitfields,
1031 (possibly both), and we're dealing with MS packing. */
1032 tree prev_saved = rli->prev_field;
1034 /* Is the prior field a bitfield? If so, handle "runs" of same
1035 type size fields. */
1036 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1038 /* If both are bitfields, nonzero, and the same size, this is
1039 the middle of a run. Zero declared size fields are special
1040 and handled as "end of run". (Note: it's nonzero declared
1041 size, but equal type sizes!) (Since we know that both
1042 the current and previous fields are bitfields by the
1043 time we check it, DECL_SIZE must be present for both.) */
1044 if (DECL_BIT_FIELD_TYPE (field)
1045 && !integer_zerop (DECL_SIZE (field))
1046 && !integer_zerop (DECL_SIZE (rli->prev_field))
1047 && host_integerp (DECL_SIZE (rli->prev_field), 0)
1048 && host_integerp (TYPE_SIZE (type), 0)
1049 && simple_cst_equal (TYPE_SIZE (type),
1050 TYPE_SIZE (TREE_TYPE (rli->prev_field))))
1052 /* We're in the middle of a run of equal type size fields; make
1053 sure we realign if we run out of bits. (Not decl size,
1055 HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 0);
1057 if (rli->remaining_in_alignment < bitsize)
1059 /* out of bits; bump up to next 'word'. */
1060 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1062 = size_binop (PLUS_EXPR, TYPE_SIZE (type),
1063 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1064 rli->prev_field = field;
1065 rli->remaining_in_alignment
1066 = tree_low_cst (TYPE_SIZE (type), 0);
1069 rli->remaining_in_alignment -= bitsize;
1073 /* End of a run: if leaving a run of bitfields of the same type
1074 size, we have to "use up" the rest of the bits of the type
1077 Compute the new position as the sum of the size for the prior
1078 type and where we first started working on that type.
1079 Note: since the beginning of the field was aligned then
1080 of course the end will be too. No round needed. */
1082 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1084 tree type_size = TYPE_SIZE (TREE_TYPE (rli->prev_field));
1087 = size_binop (PLUS_EXPR, type_size,
1088 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1091 /* We "use up" size zero fields; the code below should behave
1092 as if the prior field was not a bitfield. */
1095 /* Cause a new bitfield to be captured, either this time (if
1096 currently a bitfield) or next time we see one. */
1097 if (!DECL_BIT_FIELD_TYPE(field)
1098 || integer_zerop (DECL_SIZE (field)))
1099 rli->prev_field = NULL;
1102 normalize_rli (rli);
1105 /* If we're starting a new run of same size type bitfields
1106 (or a run of non-bitfields), set up the "first of the run"
1109 That is, if the current field is not a bitfield, or if there
1110 was a prior bitfield the type sizes differ, or if there wasn't
1111 a prior bitfield the size of the current field is nonzero.
1113 Note: we must be sure to test ONLY the type size if there was
1114 a prior bitfield and ONLY for the current field being zero if
1117 if (!DECL_BIT_FIELD_TYPE (field)
1118 || ( prev_saved != NULL
1119 ? !simple_cst_equal (TYPE_SIZE (type),
1120 TYPE_SIZE (TREE_TYPE (prev_saved)))
1121 : !integer_zerop (DECL_SIZE (field)) ))
1123 /* Never smaller than a byte for compatibility. */
1124 unsigned int type_align = BITS_PER_UNIT;
1126 /* (When not a bitfield), we could be seeing a flex array (with
1127 no DECL_SIZE). Since we won't be using remaining_in_alignment
1128 until we see a bitfield (and come by here again) we just skip
1130 if (DECL_SIZE (field) != NULL
1131 && host_integerp (TYPE_SIZE (TREE_TYPE (field)), 0)
1132 && host_integerp (DECL_SIZE (field), 0))
1133 rli->remaining_in_alignment
1134 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field)), 0)
1135 - tree_low_cst (DECL_SIZE (field), 0);
1137 /* Now align (conventionally) for the new type. */
1138 if (!DECL_PACKED(field))
1139 type_align = MAX(TYPE_ALIGN (type), type_align);
1142 && DECL_BIT_FIELD_TYPE (prev_saved)
1143 /* If the previous bit-field is zero-sized, we've already
1144 accounted for its alignment needs (or ignored it, if
1145 appropriate) while placing it. */
1146 && ! integer_zerop (DECL_SIZE (prev_saved)))
1147 type_align = MAX (type_align,
1148 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1150 if (maximum_field_alignment != 0)
1151 type_align = MIN (type_align, maximum_field_alignment);
1153 rli->bitpos = round_up (rli->bitpos, type_align);
1155 /* If we really aligned, don't allow subsequent bitfields
1157 rli->prev_field = NULL;
1161 /* Offset so far becomes the position of this field after normalizing. */
1162 normalize_rli (rli);
1163 DECL_FIELD_OFFSET (field) = rli->offset;
1164 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1165 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1167 /* If this field ended up more aligned than we thought it would be (we
1168 approximate this by seeing if its position changed), lay out the field
1169 again; perhaps we can use an integral mode for it now. */
1170 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1171 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1172 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1173 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1174 actual_align = BIGGEST_ALIGNMENT;
1175 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1176 actual_align = (BITS_PER_UNIT
1177 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1178 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1180 actual_align = DECL_OFFSET_ALIGN (field);
1182 if (known_align != actual_align)
1183 layout_decl (field, actual_align);
1185 /* Only the MS bitfields use this. */
1186 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1187 rli->prev_field = field;
1189 /* Now add size of this field to the size of the record. If the size is
1190 not constant, treat the field as being a multiple of bytes and just
1191 adjust the offset, resetting the bit position. Otherwise, apportion the
1192 size amongst the bit position and offset. First handle the case of an
1193 unspecified size, which can happen when we have an invalid nested struct
1194 definition, such as struct j { struct j { int i; } }. The error message
1195 is printed in finish_struct. */
1196 if (DECL_SIZE (field) == 0)
1198 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1199 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1202 = size_binop (PLUS_EXPR, rli->offset,
1204 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1205 bitsize_unit_node)));
1207 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1208 rli->bitpos = bitsize_zero_node;
1209 rli->offset_align = MIN (rli->offset_align, desired_align);
1213 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1214 normalize_rli (rli);
1218 /* Assuming that all the fields have been laid out, this function uses
1219 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1220 indicated by RLI. */
1223 finalize_record_size (record_layout_info rli)
1225 tree unpadded_size, unpadded_size_unit;
1227 /* Now we want just byte and bit offsets, so set the offset alignment
1228 to be a byte and then normalize. */
1229 rli->offset_align = BITS_PER_UNIT;
1230 normalize_rli (rli);
1232 /* Determine the desired alignment. */
1233 #ifdef ROUND_TYPE_ALIGN
1234 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1237 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1240 /* Compute the size so far. Be sure to allow for extra bits in the
1241 size in bytes. We have guaranteed above that it will be no more
1242 than a single byte. */
1243 unpadded_size = rli_size_so_far (rli);
1244 unpadded_size_unit = rli_size_unit_so_far (rli);
1245 if (! integer_zerop (rli->bitpos))
1247 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1249 /* Round the size up to be a multiple of the required alignment. */
1250 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1251 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1252 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1254 if (warn_padded && TREE_CONSTANT (unpadded_size)
1255 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1256 warning ("padding struct size to alignment boundary");
1258 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1259 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1260 && TREE_CONSTANT (unpadded_size))
1264 #ifdef ROUND_TYPE_ALIGN
1266 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1268 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1271 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1272 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1274 TYPE_PACKED (rli->t) = 0;
1276 if (TYPE_NAME (rli->t))
1280 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1281 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1283 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1285 if (STRICT_ALIGNMENT)
1286 warning ("packed attribute causes inefficient alignment for `%s'", name);
1288 warning ("packed attribute is unnecessary for `%s'", name);
1292 if (STRICT_ALIGNMENT)
1293 warning ("packed attribute causes inefficient alignment");
1295 warning ("packed attribute is unnecessary");
1301 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1304 compute_record_mode (tree type)
1307 enum machine_mode mode = VOIDmode;
1309 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1310 However, if possible, we use a mode that fits in a register
1311 instead, in order to allow for better optimization down the
1313 TYPE_MODE (type) = BLKmode;
1315 if (! host_integerp (TYPE_SIZE (type), 1))
1318 /* A record which has any BLKmode members must itself be
1319 BLKmode; it can't go in a register. Unless the member is
1320 BLKmode only because it isn't aligned. */
1321 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1323 if (TREE_CODE (field) != FIELD_DECL)
1326 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1327 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1328 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))
1329 && !(TYPE_SIZE (TREE_TYPE (field)) != 0
1330 && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))))
1331 || ! host_integerp (bit_position (field), 1)
1332 || DECL_SIZE (field) == 0
1333 || ! host_integerp (DECL_SIZE (field), 1))
1336 /* If this field is the whole struct, remember its mode so
1337 that, say, we can put a double in a class into a DF
1338 register instead of forcing it to live in the stack. */
1339 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1340 mode = DECL_MODE (field);
1342 #ifdef MEMBER_TYPE_FORCES_BLK
1343 /* With some targets, eg. c4x, it is sub-optimal
1344 to access an aligned BLKmode structure as a scalar. */
1346 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1348 #endif /* MEMBER_TYPE_FORCES_BLK */
1351 /* If we only have one real field; use its mode. This only applies to
1352 RECORD_TYPE. This does not apply to unions. */
1353 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1354 TYPE_MODE (type) = mode;
1356 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1358 /* If structure's known alignment is less than what the scalar
1359 mode would need, and it matters, then stick with BLKmode. */
1360 if (TYPE_MODE (type) != BLKmode
1362 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1363 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1365 /* If this is the only reason this type is BLKmode, then
1366 don't force containing types to be BLKmode. */
1367 TYPE_NO_FORCE_BLK (type) = 1;
1368 TYPE_MODE (type) = BLKmode;
1372 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1376 finalize_type_size (tree type)
1378 /* Normally, use the alignment corresponding to the mode chosen.
1379 However, where strict alignment is not required, avoid
1380 over-aligning structures, since most compilers do not do this
1383 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1384 && (STRICT_ALIGNMENT
1385 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1386 && TREE_CODE (type) != QUAL_UNION_TYPE
1387 && TREE_CODE (type) != ARRAY_TYPE)))
1389 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1390 TYPE_USER_ALIGN (type) = 0;
1393 /* Do machine-dependent extra alignment. */
1394 #ifdef ROUND_TYPE_ALIGN
1396 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1399 /* If we failed to find a simple way to calculate the unit size
1400 of the type, find it by division. */
1401 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1402 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1403 result will fit in sizetype. We will get more efficient code using
1404 sizetype, so we force a conversion. */
1405 TYPE_SIZE_UNIT (type)
1406 = convert (sizetype,
1407 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1408 bitsize_unit_node));
1410 if (TYPE_SIZE (type) != 0)
1412 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1413 TYPE_SIZE_UNIT (type)
1414 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1417 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1418 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1419 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1420 if (TYPE_SIZE_UNIT (type) != 0
1421 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1422 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1424 /* Also layout any other variants of the type. */
1425 if (TYPE_NEXT_VARIANT (type)
1426 || type != TYPE_MAIN_VARIANT (type))
1429 /* Record layout info of this variant. */
1430 tree size = TYPE_SIZE (type);
1431 tree size_unit = TYPE_SIZE_UNIT (type);
1432 unsigned int align = TYPE_ALIGN (type);
1433 unsigned int user_align = TYPE_USER_ALIGN (type);
1434 enum machine_mode mode = TYPE_MODE (type);
1436 /* Copy it into all variants. */
1437 for (variant = TYPE_MAIN_VARIANT (type);
1439 variant = TYPE_NEXT_VARIANT (variant))
1441 TYPE_SIZE (variant) = size;
1442 TYPE_SIZE_UNIT (variant) = size_unit;
1443 TYPE_ALIGN (variant) = align;
1444 TYPE_USER_ALIGN (variant) = user_align;
1445 TYPE_MODE (variant) = mode;
1450 /* Do all of the work required to layout the type indicated by RLI,
1451 once the fields have been laid out. This function will call `free'
1452 for RLI, unless FREE_P is false. Passing a value other than false
1453 for FREE_P is bad practice; this option only exists to support the
1457 finish_record_layout (record_layout_info rli, int free_p)
1459 /* Compute the final size. */
1460 finalize_record_size (rli);
1462 /* Compute the TYPE_MODE for the record. */
1463 compute_record_mode (rli->t);
1465 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1466 finalize_type_size (rli->t);
1468 /* Lay out any static members. This is done now because their type
1469 may use the record's type. */
1470 while (rli->pending_statics)
1472 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1473 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1482 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1483 NAME, its fields are chained in reverse on FIELDS.
1485 If ALIGN_TYPE is non-null, it is given the same alignment as
1489 finish_builtin_struct (tree type, const char *name, tree fields,
1494 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1496 DECL_FIELD_CONTEXT (fields) = type;
1497 next = TREE_CHAIN (fields);
1498 TREE_CHAIN (fields) = tail;
1500 TYPE_FIELDS (type) = tail;
1504 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1505 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1509 #if 0 /* not yet, should get fixed properly later */
1510 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1512 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1514 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1515 layout_decl (TYPE_NAME (type), 0);
1518 /* Calculate the mode, size, and alignment for TYPE.
1519 For an array type, calculate the element separation as well.
1520 Record TYPE on the chain of permanent or temporary types
1521 so that dbxout will find out about it.
1523 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1524 layout_type does nothing on such a type.
1526 If the type is incomplete, its TYPE_SIZE remains zero. */
1529 layout_type (tree type)
1534 if (type == error_mark_node)
1537 /* Do nothing if type has been laid out before. */
1538 if (TYPE_SIZE (type))
1541 switch (TREE_CODE (type))
1544 /* This kind of type is the responsibility
1545 of the language-specific code. */
1548 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1549 if (TYPE_PRECISION (type) == 0)
1550 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1552 /* ... fall through ... */
1557 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1558 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1559 TYPE_UNSIGNED (type) = 1;
1561 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1563 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1564 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1568 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1569 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1570 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1574 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1576 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1577 (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE
1578 ? MODE_COMPLEX_FLOAT : MODE_COMPLEX_INT),
1580 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1581 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1585 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1586 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1587 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1591 /* This is an incomplete type and so doesn't have a size. */
1592 TYPE_ALIGN (type) = 1;
1593 TYPE_USER_ALIGN (type) = 0;
1594 TYPE_MODE (type) = VOIDmode;
1598 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1599 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1600 /* A pointer might be MODE_PARTIAL_INT,
1601 but ptrdiff_t must be integral. */
1602 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1607 /* It's hard to see what the mode and size of a function ought to
1608 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1609 make it consistent with that. */
1610 TYPE_MODE (type) = mode_for_size (FUNCTION_BOUNDARY, MODE_INT, 0);
1611 TYPE_SIZE (type) = bitsize_int (FUNCTION_BOUNDARY);
1612 TYPE_SIZE_UNIT (type) = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
1616 case REFERENCE_TYPE:
1619 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1620 && reference_types_internal)
1621 ? Pmode : TYPE_MODE (type));
1623 int nbits = GET_MODE_BITSIZE (mode);
1625 TYPE_SIZE (type) = bitsize_int (nbits);
1626 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1627 TYPE_UNSIGNED (type) = 1;
1628 TYPE_PRECISION (type) = nbits;
1634 tree index = TYPE_DOMAIN (type);
1635 tree element = TREE_TYPE (type);
1637 build_pointer_type (element);
1639 /* We need to know both bounds in order to compute the size. */
1640 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1641 && TYPE_SIZE (element))
1643 tree ub = TYPE_MAX_VALUE (index);
1644 tree lb = TYPE_MIN_VALUE (index);
1648 /* The initial subtraction should happen in the original type so
1649 that (possible) negative values are handled appropriately. */
1650 length = size_binop (PLUS_EXPR, size_one_node,
1652 fold (build (MINUS_EXPR,
1656 /* Special handling for arrays of bits (for Chill). */
1657 element_size = TYPE_SIZE (element);
1658 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1659 && (integer_zerop (TYPE_MAX_VALUE (element))
1660 || integer_onep (TYPE_MAX_VALUE (element)))
1661 && host_integerp (TYPE_MIN_VALUE (element), 1))
1663 HOST_WIDE_INT maxvalue
1664 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1665 HOST_WIDE_INT minvalue
1666 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1668 if (maxvalue - minvalue == 1
1669 && (maxvalue == 1 || maxvalue == 0))
1670 element_size = integer_one_node;
1673 /* If neither bound is a constant and sizetype is signed, make
1674 sure the size is never negative. We should really do this
1675 if *either* bound is non-constant, but this is the best
1676 compromise between C and Ada. */
1677 if (!TYPE_UNSIGNED (sizetype)
1678 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
1679 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
1680 length = size_binop (MAX_EXPR, length, size_zero_node);
1682 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1683 convert (bitsizetype, length));
1685 /* If we know the size of the element, calculate the total
1686 size directly, rather than do some division thing below.
1687 This optimization helps Fortran assumed-size arrays
1688 (where the size of the array is determined at runtime)
1690 Note that we can't do this in the case where the size of
1691 the elements is one bit since TYPE_SIZE_UNIT cannot be
1692 set correctly in that case. */
1693 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1694 TYPE_SIZE_UNIT (type)
1695 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1698 /* Now round the alignment and size,
1699 using machine-dependent criteria if any. */
1701 #ifdef ROUND_TYPE_ALIGN
1703 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1705 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1707 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1708 TYPE_MODE (type) = BLKmode;
1709 if (TYPE_SIZE (type) != 0
1710 #ifdef MEMBER_TYPE_FORCES_BLK
1711 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1713 /* BLKmode elements force BLKmode aggregate;
1714 else extract/store fields may lose. */
1715 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1716 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1718 /* One-element arrays get the component type's mode. */
1719 if (simple_cst_equal (TYPE_SIZE (type),
1720 TYPE_SIZE (TREE_TYPE (type))))
1721 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1724 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1726 if (TYPE_MODE (type) != BLKmode
1727 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1728 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1729 && TYPE_MODE (type) != BLKmode)
1731 TYPE_NO_FORCE_BLK (type) = 1;
1732 TYPE_MODE (type) = BLKmode;
1740 case QUAL_UNION_TYPE:
1743 record_layout_info rli;
1745 /* Initialize the layout information. */
1746 rli = start_record_layout (type);
1748 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1749 in the reverse order in building the COND_EXPR that denotes
1750 its size. We reverse them again later. */
1751 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1752 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1754 /* Place all the fields. */
1755 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1756 place_field (rli, field);
1758 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1759 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1761 if (lang_adjust_rli)
1762 (*lang_adjust_rli) (rli);
1764 /* Finish laying out the record. */
1765 finish_record_layout (rli, /*free_p=*/true);
1769 case SET_TYPE: /* Used by Chill and Pascal. */
1770 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1771 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1775 #ifndef SET_WORD_SIZE
1776 #define SET_WORD_SIZE BITS_PER_WORD
1778 unsigned int alignment
1779 = set_alignment ? set_alignment : SET_WORD_SIZE;
1780 HOST_WIDE_INT size_in_bits
1781 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), 0)
1782 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0) + 1);
1783 HOST_WIDE_INT rounded_size
1784 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1786 if (rounded_size > (int) alignment)
1787 TYPE_MODE (type) = BLKmode;
1789 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1791 TYPE_SIZE (type) = bitsize_int (rounded_size);
1792 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1793 TYPE_ALIGN (type) = alignment;
1794 TYPE_USER_ALIGN (type) = 0;
1795 TYPE_PRECISION (type) = size_in_bits;
1800 /* The size may vary in different languages, so the language front end
1801 should fill in the size. */
1802 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1803 TYPE_USER_ALIGN (type) = 0;
1804 TYPE_MODE (type) = BLKmode;
1811 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1812 records and unions, finish_record_layout already called this
1814 if (TREE_CODE (type) != RECORD_TYPE
1815 && TREE_CODE (type) != UNION_TYPE
1816 && TREE_CODE (type) != QUAL_UNION_TYPE)
1817 finalize_type_size (type);
1819 /* If this type is created before sizetype has been permanently set,
1820 record it so set_sizetype can fix it up. */
1822 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1824 /* If an alias set has been set for this aggregate when it was incomplete,
1825 force it into alias set 0.
1826 This is too conservative, but we cannot call record_component_aliases
1827 here because some frontends still change the aggregates after
1829 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1830 TYPE_ALIAS_SET (type) = 0;
1833 /* Create and return a type for signed integers of PRECISION bits. */
1836 make_signed_type (int precision)
1838 tree type = make_node (INTEGER_TYPE);
1840 TYPE_PRECISION (type) = precision;
1842 fixup_signed_type (type);
1846 /* Create and return a type for unsigned integers of PRECISION bits. */
1849 make_unsigned_type (int precision)
1851 tree type = make_node (INTEGER_TYPE);
1853 TYPE_PRECISION (type) = precision;
1855 fixup_unsigned_type (type);
1859 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1860 value to enable integer types to be created. */
1863 initialize_sizetypes (void)
1865 tree t = make_node (INTEGER_TYPE);
1867 /* Set this so we do something reasonable for the build_int_2 calls
1869 integer_type_node = t;
1871 TYPE_MODE (t) = SImode;
1872 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1873 TYPE_USER_ALIGN (t) = 0;
1874 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1875 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1876 TYPE_UNSIGNED (t) = 1;
1877 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1878 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1879 TYPE_IS_SIZETYPE (t) = 1;
1881 /* 1000 avoids problems with possible overflow and is certainly
1882 larger than any size value we'd want to be storing. */
1883 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1885 /* These two must be different nodes because of the caching done in
1888 bitsizetype = copy_node (t);
1889 integer_type_node = 0;
1892 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1893 Also update the type of any standard type's sizes made so far. */
1896 set_sizetype (tree type)
1898 int oprecision = TYPE_PRECISION (type);
1899 /* The *bitsizetype types use a precision that avoids overflows when
1900 calculating signed sizes / offsets in bits. However, when
1901 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1903 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1904 2 * HOST_BITS_PER_WIDE_INT);
1911 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1912 sizetype = copy_node (type);
1913 TYPE_ORIG_SIZE_TYPE (sizetype) = type;
1914 TYPE_IS_SIZETYPE (sizetype) = 1;
1915 bitsizetype = make_node (INTEGER_TYPE);
1916 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1917 TYPE_PRECISION (bitsizetype) = precision;
1918 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1920 if (TYPE_UNSIGNED (type))
1921 fixup_unsigned_type (bitsizetype);
1923 fixup_signed_type (bitsizetype);
1925 layout_type (bitsizetype);
1927 if (TYPE_UNSIGNED (type))
1929 usizetype = sizetype;
1930 ubitsizetype = bitsizetype;
1931 ssizetype = copy_node (make_signed_type (oprecision));
1932 sbitsizetype = copy_node (make_signed_type (precision));
1936 ssizetype = sizetype;
1937 sbitsizetype = bitsizetype;
1938 usizetype = copy_node (make_unsigned_type (oprecision));
1939 ubitsizetype = copy_node (make_unsigned_type (precision));
1942 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1944 /* Show is a sizetype, is a main type, and has no pointers to it. */
1945 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1947 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1948 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1949 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1950 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1951 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1954 /* Go down each of the types we already made and set the proper type
1955 for the sizes in them. */
1956 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1958 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE
1959 && TREE_CODE (TREE_VALUE (t)) != BOOLEAN_TYPE)
1962 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1963 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1966 early_type_list = 0;
1970 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1971 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1972 for TYPE, based on the PRECISION and whether or not the TYPE
1973 IS_UNSIGNED. PRECISION need not correspond to a width supported
1974 natively by the hardware; for example, on a machine with 8-bit,
1975 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1979 set_min_and_max_values_for_integral_type (tree type,
1988 min_value = build_int_2 (0, 0);
1990 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1991 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1992 precision - HOST_BITS_PER_WIDE_INT > 0
1993 ? ((unsigned HOST_WIDE_INT) ~0
1994 >> (HOST_BITS_PER_WIDE_INT
1995 - (precision - HOST_BITS_PER_WIDE_INT)))
2001 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2002 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
2003 (((HOST_WIDE_INT) (-1)
2004 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2005 ? precision - HOST_BITS_PER_WIDE_INT - 1
2008 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2009 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2010 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2011 ? (((HOST_WIDE_INT) 1
2012 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2016 TREE_TYPE (min_value) = type;
2017 TREE_TYPE (max_value) = type;
2018 TYPE_MIN_VALUE (type) = min_value;
2019 TYPE_MAX_VALUE (type) = max_value;
2022 /* Set the extreme values of TYPE based on its precision in bits,
2023 then lay it out. Used when make_signed_type won't do
2024 because the tree code is not INTEGER_TYPE.
2025 E.g. for Pascal, when the -fsigned-char option is given. */
2028 fixup_signed_type (tree type)
2030 int precision = TYPE_PRECISION (type);
2032 /* We can not represent properly constants greater then
2033 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2034 as they are used by i386 vector extensions and friends. */
2035 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2036 precision = HOST_BITS_PER_WIDE_INT * 2;
2038 set_min_and_max_values_for_integral_type (type, precision,
2039 /*is_unsigned=*/false);
2041 /* Lay out the type: set its alignment, size, etc. */
2045 /* Set the extreme values of TYPE based on its precision in bits,
2046 then lay it out. This is used both in `make_unsigned_type'
2047 and for enumeral types. */
2050 fixup_unsigned_type (tree type)
2052 int precision = TYPE_PRECISION (type);
2054 /* We can not represent properly constants greater then
2055 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2056 as they are used by i386 vector extensions and friends. */
2057 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2058 precision = HOST_BITS_PER_WIDE_INT * 2;
2060 set_min_and_max_values_for_integral_type (type, precision,
2061 /*is_unsigned=*/true);
2063 /* Lay out the type: set its alignment, size, etc. */
2067 /* Find the best machine mode to use when referencing a bit field of length
2068 BITSIZE bits starting at BITPOS.
2070 The underlying object is known to be aligned to a boundary of ALIGN bits.
2071 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2072 larger than LARGEST_MODE (usually SImode).
2074 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2075 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2076 mode meeting these conditions.
2078 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2079 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2080 all the conditions. */
2083 get_best_mode (int bitsize, int bitpos, unsigned int align,
2084 enum machine_mode largest_mode, int volatilep)
2086 enum machine_mode mode;
2087 unsigned int unit = 0;
2089 /* Find the narrowest integer mode that contains the bit field. */
2090 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2091 mode = GET_MODE_WIDER_MODE (mode))
2093 unit = GET_MODE_BITSIZE (mode);
2094 if ((bitpos % unit) + bitsize <= unit)
2098 if (mode == VOIDmode
2099 /* It is tempting to omit the following line
2100 if STRICT_ALIGNMENT is true.
2101 But that is incorrect, since if the bitfield uses part of 3 bytes
2102 and we use a 4-byte mode, we could get a spurious segv
2103 if the extra 4th byte is past the end of memory.
2104 (Though at least one Unix compiler ignores this problem:
2105 that on the Sequent 386 machine. */
2106 || MIN (unit, BIGGEST_ALIGNMENT) > align
2107 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2110 if (SLOW_BYTE_ACCESS && ! volatilep)
2112 enum machine_mode wide_mode = VOIDmode, tmode;
2114 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2115 tmode = GET_MODE_WIDER_MODE (tmode))
2117 unit = GET_MODE_BITSIZE (tmode);
2118 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2119 && unit <= BITS_PER_WORD
2120 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2121 && (largest_mode == VOIDmode
2122 || unit <= GET_MODE_BITSIZE (largest_mode)))
2126 if (wide_mode != VOIDmode)
2133 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2134 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2137 get_mode_bounds (enum machine_mode mode, int sign,
2138 enum machine_mode target_mode,
2139 rtx *mmin, rtx *mmax)
2141 unsigned size = GET_MODE_BITSIZE (mode);
2142 unsigned HOST_WIDE_INT min_val, max_val;
2144 if (size > HOST_BITS_PER_WIDE_INT)
2149 min_val = -((unsigned HOST_WIDE_INT) 1 << (size - 1));
2150 max_val = ((unsigned HOST_WIDE_INT) 1 << (size - 1)) - 1;
2155 max_val = ((unsigned HOST_WIDE_INT) 1 << (size - 1) << 1) - 1;
2158 *mmin = GEN_INT (trunc_int_for_mode (min_val, target_mode));
2159 *mmax = GEN_INT (trunc_int_for_mode (max_val, target_mode));
2162 #include "gt-stor-layout.h"