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 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 PARAMS ((record_layout_info));
63 static void finalize_type_size PARAMS ((tree));
64 static void place_union_field PARAMS ((record_layout_info, tree));
65 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
66 static int excess_unit_span PARAMS ((HOST_WIDE_INT, HOST_WIDE_INT,
67 HOST_WIDE_INT, HOST_WIDE_INT,
70 static unsigned int update_alignment_for_field
71 PARAMS ((record_layout_info, tree,
73 extern void debug_rli PARAMS ((record_layout_info));
75 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
77 static GTY(()) tree pending_sizes;
79 /* Nonzero means cannot safely call expand_expr now,
80 so put variable sizes onto `pending_sizes' instead. */
82 int immediate_size_expand;
84 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
88 internal_reference_types ()
90 reference_types_internal = 1;
93 /* Get a list of all the objects put on the pending sizes list. */
98 tree chain = pending_sizes;
101 /* Put each SAVE_EXPR into the current function. */
102 for (t = chain; t; t = TREE_CHAIN (t))
103 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
109 /* Return nonzero if EXPR is present on the pending sizes list. */
112 is_pending_size (expr)
117 for (t = pending_sizes; t; t = TREE_CHAIN (t))
118 if (TREE_VALUE (t) == expr)
123 /* Add EXPR to the pending sizes list. */
126 put_pending_size (expr)
129 /* Strip any simple arithmetic from EXPR to see if it has an underlying
131 while (TREE_CODE_CLASS (TREE_CODE (expr)) == '1'
132 || (TREE_CODE_CLASS (TREE_CODE (expr)) == '2'
133 && TREE_CONSTANT (TREE_OPERAND (expr, 1))))
134 expr = TREE_OPERAND (expr, 0);
136 if (TREE_CODE (expr) == SAVE_EXPR)
137 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
140 /* Put a chain of objects into the pending sizes list, which must be
144 put_pending_sizes (chain)
150 pending_sizes = chain;
153 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
154 to serve as the actual size-expression for a type or decl. */
162 /* If the language-processor is to take responsibility for variable-sized
163 items (e.g., languages which have elaboration procedures like Ada),
164 just return SIZE unchanged. Likewise for self-referential sizes and
166 if (TREE_CONSTANT (size)
167 || (*lang_hooks.decls.global_bindings_p) () < 0
168 || contains_placeholder_p (size))
171 if (TREE_CODE (size) == MINUS_EXPR && integer_onep (TREE_OPERAND (size, 1)))
172 /* If this is the upper bound of a C array, leave the minus 1 outside
173 the SAVE_EXPR so it can be folded away. */
174 TREE_OPERAND (size, 0) = save = save_expr (TREE_OPERAND (size, 0));
176 size = save = save_expr (size);
178 /* If an array with a variable number of elements is declared, and
179 the elements require destruction, we will emit a cleanup for the
180 array. That cleanup is run both on normal exit from the block
181 and in the exception-handler for the block. Normally, when code
182 is used in both ordinary code and in an exception handler it is
183 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
184 not wish to do that here; the array-size is the same in both
186 if (TREE_CODE (save) == SAVE_EXPR)
187 SAVE_EXPR_PERSISTENT_P (save) = 1;
189 if ((*lang_hooks.decls.global_bindings_p) ())
191 if (TREE_CONSTANT (size))
192 error ("type size can't be explicitly evaluated");
194 error ("variable-size type declared outside of any function");
196 return size_one_node;
199 if (immediate_size_expand)
200 expand_expr (save, const0_rtx, VOIDmode, 0);
201 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
202 /* The front-end doesn't want us to keep a list of the expressions
203 that determine sizes for variable size objects. */
206 put_pending_size (save);
211 #ifndef MAX_FIXED_MODE_SIZE
212 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
215 /* Return the machine mode to use for a nonscalar of SIZE bits.
216 The mode must be in class CLASS, and have exactly that many bits.
217 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
221 mode_for_size (size, class, limit)
223 enum mode_class class;
226 enum machine_mode mode;
228 if (limit && size > MAX_FIXED_MODE_SIZE)
231 /* Get the first mode which has this size, in the specified class. */
232 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
233 mode = GET_MODE_WIDER_MODE (mode))
234 if (GET_MODE_BITSIZE (mode) == size)
240 /* Similar, except passed a tree node. */
243 mode_for_size_tree (size, class, limit)
245 enum mode_class class;
248 if (TREE_CODE (size) != INTEGER_CST
249 /* What we really want to say here is that the size can fit in a
250 host integer, but we know there's no way we'd find a mode for
251 this many bits, so there's no point in doing the precise test. */
252 || compare_tree_int (size, 1000) > 0)
255 return mode_for_size (TREE_INT_CST_LOW (size), class, limit);
258 /* Similar, but never return BLKmode; return the narrowest mode that
259 contains at least the requested number of bits. */
262 smallest_mode_for_size (size, class)
264 enum mode_class class;
266 enum machine_mode mode;
268 /* Get the first mode which has at least this size, in the
270 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
271 mode = GET_MODE_WIDER_MODE (mode))
272 if (GET_MODE_BITSIZE (mode) >= size)
278 /* Find an integer mode of the exact same size, or BLKmode on failure. */
281 int_mode_for_mode (mode)
282 enum machine_mode mode;
284 switch (GET_MODE_CLASS (mode))
287 case MODE_PARTIAL_INT:
290 case MODE_COMPLEX_INT:
291 case MODE_COMPLEX_FLOAT:
293 case MODE_VECTOR_INT:
294 case MODE_VECTOR_FLOAT:
295 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
302 /* ... fall through ... */
312 /* Return the alignment of MODE. This will be bounded by 1 and
313 BIGGEST_ALIGNMENT. */
316 get_mode_alignment (mode)
317 enum machine_mode mode;
319 unsigned int alignment;
321 if (GET_MODE_CLASS (mode) == MODE_COMPLEX_FLOAT
322 || GET_MODE_CLASS (mode) == MODE_COMPLEX_INT)
323 alignment = GET_MODE_UNIT_SIZE (mode);
325 alignment = GET_MODE_SIZE (mode);
327 /* Extract the LSB of the size. */
328 alignment = alignment & -alignment;
329 alignment *= BITS_PER_UNIT;
331 alignment = MIN (BIGGEST_ALIGNMENT, MAX (1, alignment));
335 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
336 This can only be applied to objects of a sizetype. */
339 round_up (value, divisor)
343 tree arg = size_int_type (divisor, TREE_TYPE (value));
345 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
348 /* Likewise, but round down. */
351 round_down (value, divisor)
355 tree arg = size_int_type (divisor, TREE_TYPE (value));
357 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
360 /* Subroutine of layout_decl: Force alignment required for the data type.
361 But if the decl itself wants greater alignment, don't override that. */
364 do_type_align (tree type, tree decl)
366 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
368 DECL_ALIGN (decl) = TYPE_ALIGN (type);
369 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
373 /* Set the size, mode and alignment of a ..._DECL node.
374 TYPE_DECL does need this for C++.
375 Note that LABEL_DECL and CONST_DECL nodes do not need this,
376 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
377 Don't call layout_decl for them.
379 KNOWN_ALIGN is the amount of alignment we can assume this
380 decl has with no special effort. It is relevant only for FIELD_DECLs
381 and depends on the previous fields.
382 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
383 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
384 the record will be aligned to suit. */
387 layout_decl (decl, known_align)
389 unsigned int known_align;
391 tree type = TREE_TYPE (decl);
392 enum tree_code code = TREE_CODE (decl);
394 if (code == CONST_DECL)
396 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
397 && code != TYPE_DECL && code != FIELD_DECL)
400 if (type == error_mark_node)
401 type = void_type_node;
403 /* Usually the size and mode come from the data type without change,
404 however, the front-end may set the explicit width of the field, so its
405 size may not be the same as the size of its type. This happens with
406 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
407 also happens with other fields. For example, the C++ front-end creates
408 zero-sized fields corresponding to empty base classes, and depends on
409 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
410 size in bytes from the size in bits. If we have already set the mode,
411 don't set it again since we can be called twice for FIELD_DECLs. */
413 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
414 if (DECL_MODE (decl) == VOIDmode)
415 DECL_MODE (decl) = TYPE_MODE (type);
417 if (DECL_SIZE (decl) == 0)
419 DECL_SIZE (decl) = TYPE_SIZE (type);
420 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
423 DECL_SIZE_UNIT (decl)
424 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
427 if (code != FIELD_DECL)
428 /* For non-fields, update the alignment from the type. */
429 do_type_align (type, decl);
431 /* For fields, it's a bit more complicated... */
433 if (DECL_BIT_FIELD (decl))
435 DECL_BIT_FIELD_TYPE (decl) = type;
437 /* A zero-length bit-field affects the alignment of the next
439 if (integer_zerop (DECL_SIZE (decl))
440 && ! DECL_PACKED (decl)
441 && ! (*targetm.ms_bitfield_layout_p) (DECL_FIELD_CONTEXT (decl)))
443 #ifdef PCC_BITFIELD_TYPE_MATTERS
444 if (PCC_BITFIELD_TYPE_MATTERS)
445 do_type_align (type, decl);
449 #ifdef EMPTY_FIELD_BOUNDARY
450 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
452 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
453 DECL_USER_ALIGN (decl) = 0;
459 /* See if we can use an ordinary integer mode for a bit-field.
460 Conditions are: a fixed size that is correct for another mode
461 and occupying a complete byte or bytes on proper boundary. */
462 if (TYPE_SIZE (type) != 0
463 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
464 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
466 enum machine_mode xmode
467 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
469 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
471 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
473 DECL_MODE (decl) = xmode;
474 DECL_BIT_FIELD (decl) = 0;
478 /* Turn off DECL_BIT_FIELD if we won't need it set. */
479 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
480 && known_align >= TYPE_ALIGN (type)
481 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
482 DECL_BIT_FIELD (decl) = 0;
484 else if (DECL_PACKED (decl) && DECL_USER_ALIGN (decl))
485 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
486 round up; we'll reduce it again below. */;
488 do_type_align (type, decl);
490 /* If the field is of variable size, we can't misalign it since we
491 have no way to make a temporary to align the result. But this
492 isn't an issue if the decl is not addressable. Likewise if it
493 is of unknown size. */
494 if (DECL_PACKED (decl)
495 && !DECL_USER_ALIGN (decl)
496 && (DECL_NONADDRESSABLE_P (decl)
497 || DECL_SIZE_UNIT (decl) == 0
498 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
499 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
501 /* Should this be controlled by DECL_USER_ALIGN, too? */
502 if (maximum_field_alignment != 0)
503 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
504 if (! DECL_USER_ALIGN (decl))
506 /* Some targets (i.e. i386, VMS) limit struct field alignment
507 to a lower boundary than alignment of variables unless
508 it was overridden by attribute aligned. */
509 #ifdef BIGGEST_FIELD_ALIGNMENT
511 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
513 #ifdef ADJUST_FIELD_ALIGN
514 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
519 /* Evaluate nonconstant size only once, either now or as soon as safe. */
520 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
521 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
522 if (DECL_SIZE_UNIT (decl) != 0
523 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
524 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
526 /* If requested, warn about definitions of large data objects. */
528 && (code == VAR_DECL || code == PARM_DECL)
529 && ! DECL_EXTERNAL (decl))
531 tree size = DECL_SIZE_UNIT (decl);
533 if (size != 0 && TREE_CODE (size) == INTEGER_CST
534 && compare_tree_int (size, larger_than_size) > 0)
536 unsigned int size_as_int = TREE_INT_CST_LOW (size);
538 if (compare_tree_int (size, size_as_int) == 0)
539 warning_with_decl (decl, "size of `%s' is %d bytes", size_as_int);
541 warning_with_decl (decl, "size of `%s' is larger than %d bytes",
547 /* Hook for a front-end function that can modify the record layout as needed
548 immediately before it is finalized. */
550 void (*lang_adjust_rli) PARAMS ((record_layout_info)) = 0;
553 set_lang_adjust_rli (f)
554 void (*f) PARAMS ((record_layout_info));
559 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
560 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
561 is to be passed to all other layout functions for this record. It is the
562 responsibility of the caller to call `free' for the storage returned.
563 Note that garbage collection is not permitted until we finish laying
567 start_record_layout (t)
570 record_layout_info rli
571 = (record_layout_info) xmalloc (sizeof (struct record_layout_info_s));
575 /* If the type has a minimum specified alignment (via an attribute
576 declaration, for example) use it -- otherwise, start with a
577 one-byte alignment. */
578 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
579 rli->unpacked_align = rli->record_align;
580 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
582 #ifdef STRUCTURE_SIZE_BOUNDARY
583 /* Packed structures don't need to have minimum size. */
584 if (! TYPE_PACKED (t))
585 rli->record_align = MAX (rli->record_align, (unsigned) STRUCTURE_SIZE_BOUNDARY);
588 rli->offset = size_zero_node;
589 rli->bitpos = bitsize_zero_node;
591 rli->pending_statics = 0;
592 rli->packed_maybe_necessary = 0;
597 /* These four routines perform computations that convert between
598 the offset/bitpos forms and byte and bit offsets. */
601 bit_from_pos (offset, bitpos)
604 return size_binop (PLUS_EXPR, bitpos,
605 size_binop (MULT_EXPR, convert (bitsizetype, offset),
610 byte_from_pos (offset, bitpos)
613 return size_binop (PLUS_EXPR, offset,
615 size_binop (TRUNC_DIV_EXPR, bitpos,
616 bitsize_unit_node)));
620 pos_from_bit (poffset, pbitpos, off_align, pos)
621 tree *poffset, *pbitpos;
622 unsigned int off_align;
625 *poffset = size_binop (MULT_EXPR,
627 size_binop (FLOOR_DIV_EXPR, pos,
628 bitsize_int (off_align))),
629 size_int (off_align / BITS_PER_UNIT));
630 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
633 /* Given a pointer to bit and byte offsets and an offset alignment,
634 normalize the offsets so they are within the alignment. */
637 normalize_offset (poffset, pbitpos, off_align)
638 tree *poffset, *pbitpos;
639 unsigned int off_align;
641 /* If the bit position is now larger than it should be, adjust it
643 if (compare_tree_int (*pbitpos, off_align) >= 0)
645 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
646 bitsize_int (off_align));
649 = size_binop (PLUS_EXPR, *poffset,
650 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
651 size_int (off_align / BITS_PER_UNIT)));
654 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
658 /* Print debugging information about the information in RLI. */
662 record_layout_info rli;
664 print_node_brief (stderr, "type", rli->t, 0);
665 print_node_brief (stderr, "\noffset", rli->offset, 0);
666 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
668 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
669 rli->record_align, rli->unpacked_align,
671 if (rli->packed_maybe_necessary)
672 fprintf (stderr, "packed may be necessary\n");
674 if (rli->pending_statics)
676 fprintf (stderr, "pending statics:\n");
677 debug_tree (rli->pending_statics);
681 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
682 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
686 record_layout_info rli;
688 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
691 /* Returns the size in bytes allocated so far. */
694 rli_size_unit_so_far (rli)
695 record_layout_info rli;
697 return byte_from_pos (rli->offset, rli->bitpos);
700 /* Returns the size in bits allocated so far. */
703 rli_size_so_far (rli)
704 record_layout_info rli;
706 return bit_from_pos (rli->offset, rli->bitpos);
709 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
710 the next available location is given by KNOWN_ALIGN. Update the
711 variable alignment fields in RLI, and return the alignment to give
715 update_alignment_for_field (rli, field, known_align)
716 record_layout_info rli;
718 unsigned int known_align;
720 /* The alignment required for FIELD. */
721 unsigned int desired_align;
722 /* The type of this field. */
723 tree type = TREE_TYPE (field);
724 /* True if the field was explicitly aligned by the user. */
728 /* Lay out the field so we know what alignment it needs. */
729 layout_decl (field, known_align);
730 desired_align = DECL_ALIGN (field);
731 user_align = DECL_USER_ALIGN (field);
733 is_bitfield = (type != error_mark_node
734 && DECL_BIT_FIELD_TYPE (field)
735 && ! integer_zerop (TYPE_SIZE (type)));
737 /* Record must have at least as much alignment as any field.
738 Otherwise, the alignment of the field within the record is
740 if (is_bitfield && (* targetm.ms_bitfield_layout_p) (rli->t))
742 /* Here, the alignment of the underlying type of a bitfield can
743 affect the alignment of a record; even a zero-sized field
744 can do this. The alignment should be to the alignment of
745 the type, except that for zero-size bitfields this only
746 applies if there was an immediately prior, nonzero-size
747 bitfield. (That's the way it is, experimentally.) */
748 if (! integer_zerop (DECL_SIZE (field))
749 ? ! DECL_PACKED (field)
751 && DECL_BIT_FIELD_TYPE (rli->prev_field)
752 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
754 unsigned int type_align = TYPE_ALIGN (type);
755 type_align = MAX (type_align, desired_align);
756 if (maximum_field_alignment != 0)
757 type_align = MIN (type_align, maximum_field_alignment);
758 rli->record_align = MAX (rli->record_align, type_align);
759 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
762 #ifdef PCC_BITFIELD_TYPE_MATTERS
763 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
765 /* Named bit-fields cause the entire structure to have the
766 alignment implied by their type. */
767 if (DECL_NAME (field) != 0)
769 unsigned int type_align = TYPE_ALIGN (type);
771 #ifdef ADJUST_FIELD_ALIGN
772 if (! TYPE_USER_ALIGN (type))
773 type_align = ADJUST_FIELD_ALIGN (field, type_align);
776 if (maximum_field_alignment != 0)
777 type_align = MIN (type_align, maximum_field_alignment);
778 else if (DECL_PACKED (field))
779 type_align = MIN (type_align, BITS_PER_UNIT);
781 /* The alignment of the record is increased to the maximum
782 of the current alignment, the alignment indicated on the
783 field (i.e., the alignment specified by an __aligned__
784 attribute), and the alignment indicated by the type of
786 rli->record_align = MAX (rli->record_align, desired_align);
787 rli->record_align = MAX (rli->record_align, type_align);
790 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
791 user_align |= TYPE_USER_ALIGN (type);
797 rli->record_align = MAX (rli->record_align, desired_align);
798 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
801 TYPE_USER_ALIGN (rli->t) |= user_align;
803 return desired_align;
806 /* Called from place_field to handle unions. */
809 place_union_field (rli, field)
810 record_layout_info rli;
813 update_alignment_for_field (rli, field, /*known_align=*/0);
815 DECL_FIELD_OFFSET (field) = size_zero_node;
816 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
817 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
819 /* We assume the union's size will be a multiple of a byte so we don't
820 bother with BITPOS. */
821 if (TREE_CODE (rli->t) == UNION_TYPE)
822 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
823 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
824 rli->offset = fold (build (COND_EXPR, sizetype,
825 DECL_QUALIFIER (field),
826 DECL_SIZE_UNIT (field), rli->offset));
829 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
830 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
831 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
832 units of alignment than the underlying TYPE. */
834 excess_unit_span (byte_offset, bit_offset, size, align, type)
835 HOST_WIDE_INT byte_offset, bit_offset, size, align;
838 /* Note that the calculation of OFFSET might overflow; we calculate it so
839 that we still get the right result as long as ALIGN is a power of two. */
840 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
842 offset = offset % align;
843 return ((offset + size + align - 1) / align
844 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
849 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
850 is a FIELD_DECL to be added after those fields already present in
851 T. (FIELD is not actually added to the TYPE_FIELDS list here;
852 callers that desire that behavior must manually perform that step.) */
855 place_field (rli, field)
856 record_layout_info rli;
859 /* The alignment required for FIELD. */
860 unsigned int desired_align;
861 /* The alignment FIELD would have if we just dropped it into the
862 record as it presently stands. */
863 unsigned int known_align;
864 unsigned int actual_align;
865 /* The type of this field. */
866 tree type = TREE_TYPE (field);
868 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
871 /* If FIELD is static, then treat it like a separate variable, not
872 really like a structure field. If it is a FUNCTION_DECL, it's a
873 method. In both cases, all we do is lay out the decl, and we do
874 it *after* the record is laid out. */
875 if (TREE_CODE (field) == VAR_DECL)
877 rli->pending_statics = tree_cons (NULL_TREE, field,
878 rli->pending_statics);
882 /* Enumerators and enum types which are local to this class need not
883 be laid out. Likewise for initialized constant fields. */
884 else if (TREE_CODE (field) != FIELD_DECL)
887 /* Unions are laid out very differently than records, so split
888 that code off to another function. */
889 else if (TREE_CODE (rli->t) != RECORD_TYPE)
891 place_union_field (rli, field);
895 /* Work out the known alignment so far. Note that A & (-A) is the
896 value of the least-significant bit in A that is one. */
897 if (! integer_zerop (rli->bitpos))
898 known_align = (tree_low_cst (rli->bitpos, 1)
899 & - tree_low_cst (rli->bitpos, 1));
900 else if (integer_zerop (rli->offset))
901 known_align = BIGGEST_ALIGNMENT;
902 else if (host_integerp (rli->offset, 1))
903 known_align = (BITS_PER_UNIT
904 * (tree_low_cst (rli->offset, 1)
905 & - tree_low_cst (rli->offset, 1)));
907 known_align = rli->offset_align;
909 desired_align = update_alignment_for_field (rli, field, known_align);
911 if (warn_packed && DECL_PACKED (field))
913 if (known_align >= TYPE_ALIGN (type))
915 if (TYPE_ALIGN (type) > desired_align)
917 if (STRICT_ALIGNMENT)
918 warning_with_decl (field, "packed attribute causes inefficient alignment for `%s'");
920 warning_with_decl (field, "packed attribute is unnecessary for `%s'");
924 rli->packed_maybe_necessary = 1;
927 /* Does this field automatically have alignment it needs by virtue
928 of the fields that precede it and the record's own alignment? */
929 if (known_align < desired_align)
931 /* No, we need to skip space before this field.
932 Bump the cumulative size to multiple of field alignment. */
935 warning_with_decl (field, "padding struct to align `%s'");
937 /* If the alignment is still within offset_align, just align
939 if (desired_align < rli->offset_align)
940 rli->bitpos = round_up (rli->bitpos, desired_align);
943 /* First adjust OFFSET by the partial bits, then align. */
945 = size_binop (PLUS_EXPR, rli->offset,
947 size_binop (CEIL_DIV_EXPR, rli->bitpos,
948 bitsize_unit_node)));
949 rli->bitpos = bitsize_zero_node;
951 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
954 if (! TREE_CONSTANT (rli->offset))
955 rli->offset_align = desired_align;
959 /* Handle compatibility with PCC. Note that if the record has any
960 variable-sized fields, we need not worry about compatibility. */
961 #ifdef PCC_BITFIELD_TYPE_MATTERS
962 if (PCC_BITFIELD_TYPE_MATTERS
963 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
964 && TREE_CODE (field) == FIELD_DECL
965 && type != error_mark_node
966 && DECL_BIT_FIELD (field)
967 && ! DECL_PACKED (field)
968 && maximum_field_alignment == 0
969 && ! integer_zerop (DECL_SIZE (field))
970 && host_integerp (DECL_SIZE (field), 1)
971 && host_integerp (rli->offset, 1)
972 && host_integerp (TYPE_SIZE (type), 1))
974 unsigned int type_align = TYPE_ALIGN (type);
975 tree dsize = DECL_SIZE (field);
976 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
977 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
978 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
980 #ifdef ADJUST_FIELD_ALIGN
981 if (! TYPE_USER_ALIGN (type))
982 type_align = ADJUST_FIELD_ALIGN (field, type_align);
985 /* A bit field may not span more units of alignment of its type
986 than its type itself. Advance to next boundary if necessary. */
987 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
988 rli->bitpos = round_up (rli->bitpos, type_align);
990 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
994 #ifdef BITFIELD_NBYTES_LIMITED
995 if (BITFIELD_NBYTES_LIMITED
996 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
997 && TREE_CODE (field) == FIELD_DECL
998 && type != error_mark_node
999 && DECL_BIT_FIELD_TYPE (field)
1000 && ! DECL_PACKED (field)
1001 && ! integer_zerop (DECL_SIZE (field))
1002 && host_integerp (DECL_SIZE (field), 1)
1003 && host_integerp (rli->offset, 1)
1004 && host_integerp (TYPE_SIZE (type), 1))
1006 unsigned int type_align = TYPE_ALIGN (type);
1007 tree dsize = DECL_SIZE (field);
1008 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
1009 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
1010 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
1012 #ifdef ADJUST_FIELD_ALIGN
1013 if (! TYPE_USER_ALIGN (type))
1014 type_align = ADJUST_FIELD_ALIGN (field, type_align);
1017 if (maximum_field_alignment != 0)
1018 type_align = MIN (type_align, maximum_field_alignment);
1019 /* ??? This test is opposite the test in the containing if
1020 statement, so this code is unreachable currently. */
1021 else if (DECL_PACKED (field))
1022 type_align = MIN (type_align, BITS_PER_UNIT);
1024 /* A bit field may not span the unit of alignment of its type.
1025 Advance to next boundary if necessary. */
1026 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
1027 rli->bitpos = round_up (rli->bitpos, type_align);
1029 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
1033 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1035 When a bit field is inserted into a packed record, the whole
1036 size of the underlying type is used by one or more same-size
1037 adjacent bitfields. (That is, if its long:3, 32 bits is
1038 used in the record, and any additional adjacent long bitfields are
1039 packed into the same chunk of 32 bits. However, if the size
1040 changes, a new field of that size is allocated.) In an unpacked
1041 record, this is the same as using alignment, but not equivalent
1044 Note: for compatibility, we use the type size, not the type alignment
1045 to determine alignment, since that matches the documentation */
1047 if ((* targetm.ms_bitfield_layout_p) (rli->t)
1048 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1049 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1051 /* At this point, either the prior or current are bitfields,
1052 (possibly both), and we're dealing with MS packing. */
1053 tree prev_saved = rli->prev_field;
1055 /* Is the prior field a bitfield? If so, handle "runs" of same
1056 type size fields. */
1057 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1059 /* If both are bitfields, nonzero, and the same size, this is
1060 the middle of a run. Zero declared size fields are special
1061 and handled as "end of run". (Note: it's nonzero declared
1062 size, but equal type sizes!) (Since we know that both
1063 the current and previous fields are bitfields by the
1064 time we check it, DECL_SIZE must be present for both.) */
1065 if (DECL_BIT_FIELD_TYPE (field)
1066 && !integer_zerop (DECL_SIZE (field))
1067 && !integer_zerop (DECL_SIZE (rli->prev_field))
1068 && simple_cst_equal (TYPE_SIZE (type),
1069 TYPE_SIZE (TREE_TYPE (rli->prev_field))) )
1071 /* We're in the middle of a run of equal type size fields; make
1072 sure we realign if we run out of bits. (Not decl size,
1074 int bitsize = TREE_INT_CST_LOW (DECL_SIZE (field));
1075 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1077 if (rli->remaining_in_alignment < bitsize)
1079 /* out of bits; bump up to next 'word'. */
1080 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1081 rli->bitpos = size_binop (PLUS_EXPR,
1083 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1084 rli->prev_field = field;
1085 rli->remaining_in_alignment = TREE_INT_CST_LOW (type_size);
1087 rli->remaining_in_alignment -= bitsize;
1091 /* End of a run: if leaving a run of bitfields of the same type
1092 size, we have to "use up" the rest of the bits of the type
1095 Compute the new position as the sum of the size for the prior
1096 type and where we first started working on that type.
1097 Note: since the beginning of the field was aligned then
1098 of course the end will be too. No round needed. */
1100 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1102 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1103 rli->bitpos = size_binop (PLUS_EXPR,
1105 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1109 /* We "use up" size zero fields; the code below should behave
1110 as if the prior field was not a bitfield. */
1114 /* Cause a new bitfield to be captured, either this time (if
1115 currently a bitfield) or next time we see one. */
1116 if (!DECL_BIT_FIELD_TYPE(field)
1117 || integer_zerop (DECL_SIZE (field)))
1119 rli->prev_field = NULL;
1122 normalize_rli (rli);
1125 /* If we're starting a new run of same size type bitfields
1126 (or a run of non-bitfields), set up the "first of the run"
1129 That is, if the current field is not a bitfield, or if there
1130 was a prior bitfield the type sizes differ, or if there wasn't
1131 a prior bitfield the size of the current field is nonzero.
1133 Note: we must be sure to test ONLY the type size if there was
1134 a prior bitfield and ONLY for the current field being zero if
1137 if (!DECL_BIT_FIELD_TYPE (field)
1138 || ( prev_saved != NULL
1139 ? !simple_cst_equal (TYPE_SIZE (type),
1140 TYPE_SIZE (TREE_TYPE (prev_saved)))
1141 : !integer_zerop (DECL_SIZE (field)) ))
1143 unsigned int type_align = 8; /* Never below 8 for compatibility */
1145 /* (When not a bitfield), we could be seeing a flex array (with
1146 no DECL_SIZE). Since we won't be using remaining_in_alignment
1147 until we see a bitfield (and come by here again) we just skip
1150 if (DECL_SIZE (field) != NULL)
1151 rli->remaining_in_alignment
1152 = TREE_INT_CST_LOW (TYPE_SIZE(TREE_TYPE(field)))
1153 - TREE_INT_CST_LOW (DECL_SIZE (field));
1155 /* Now align (conventionally) for the new type. */
1156 if (!DECL_PACKED(field))
1157 type_align = MAX(TYPE_ALIGN (type), type_align);
1160 && DECL_BIT_FIELD_TYPE (prev_saved)
1161 /* If the previous bit-field is zero-sized, we've already
1162 accounted for its alignment needs (or ignored it, if
1163 appropriate) while placing it. */
1164 && ! integer_zerop (DECL_SIZE (prev_saved)))
1165 type_align = MAX (type_align,
1166 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1168 if (maximum_field_alignment != 0)
1169 type_align = MIN (type_align, maximum_field_alignment);
1171 rli->bitpos = round_up (rli->bitpos, type_align);
1172 /* If we really aligned, don't allow subsequent bitfields
1174 rli->prev_field = NULL;
1178 /* Offset so far becomes the position of this field after normalizing. */
1179 normalize_rli (rli);
1180 DECL_FIELD_OFFSET (field) = rli->offset;
1181 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1182 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1184 /* If this field ended up more aligned than we thought it would be (we
1185 approximate this by seeing if its position changed), lay out the field
1186 again; perhaps we can use an integral mode for it now. */
1187 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1188 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1189 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1190 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1191 actual_align = BIGGEST_ALIGNMENT;
1192 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1193 actual_align = (BITS_PER_UNIT
1194 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1195 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1197 actual_align = DECL_OFFSET_ALIGN (field);
1199 if (known_align != actual_align)
1200 layout_decl (field, actual_align);
1202 /* Only the MS bitfields use this. */
1203 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1204 rli->prev_field = field;
1206 /* Now add size of this field to the size of the record. If the size is
1207 not constant, treat the field as being a multiple of bytes and just
1208 adjust the offset, resetting the bit position. Otherwise, apportion the
1209 size amongst the bit position and offset. First handle the case of an
1210 unspecified size, which can happen when we have an invalid nested struct
1211 definition, such as struct j { struct j { int i; } }. The error message
1212 is printed in finish_struct. */
1213 if (DECL_SIZE (field) == 0)
1215 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1216 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1219 = size_binop (PLUS_EXPR, rli->offset,
1221 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1222 bitsize_unit_node)));
1224 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1225 rli->bitpos = bitsize_zero_node;
1226 rli->offset_align = MIN (rli->offset_align, DECL_ALIGN (field));
1230 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1231 normalize_rli (rli);
1235 /* Assuming that all the fields have been laid out, this function uses
1236 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1237 indicated by RLI. */
1240 finalize_record_size (rli)
1241 record_layout_info rli;
1243 tree unpadded_size, unpadded_size_unit;
1245 /* Now we want just byte and bit offsets, so set the offset alignment
1246 to be a byte and then normalize. */
1247 rli->offset_align = BITS_PER_UNIT;
1248 normalize_rli (rli);
1250 /* Determine the desired alignment. */
1251 #ifdef ROUND_TYPE_ALIGN
1252 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1255 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1258 /* Compute the size so far. Be sure to allow for extra bits in the
1259 size in bytes. We have guaranteed above that it will be no more
1260 than a single byte. */
1261 unpadded_size = rli_size_so_far (rli);
1262 unpadded_size_unit = rli_size_unit_so_far (rli);
1263 if (! integer_zerop (rli->bitpos))
1265 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1267 /* Round the size up to be a multiple of the required alignment */
1268 #ifdef ROUND_TYPE_SIZE
1269 TYPE_SIZE (rli->t) = ROUND_TYPE_SIZE (rli->t, unpadded_size,
1270 TYPE_ALIGN (rli->t));
1271 TYPE_SIZE_UNIT (rli->t)
1272 = ROUND_TYPE_SIZE_UNIT (rli->t, unpadded_size_unit,
1273 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1275 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1276 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1277 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1280 if (warn_padded && TREE_CONSTANT (unpadded_size)
1281 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1282 warning ("padding struct size to alignment boundary");
1284 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1285 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1286 && TREE_CONSTANT (unpadded_size))
1290 #ifdef ROUND_TYPE_ALIGN
1292 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1294 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1297 #ifdef ROUND_TYPE_SIZE
1298 unpacked_size = ROUND_TYPE_SIZE (rli->t, TYPE_SIZE (rli->t),
1299 rli->unpacked_align);
1301 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1304 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1306 TYPE_PACKED (rli->t) = 0;
1308 if (TYPE_NAME (rli->t))
1312 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1313 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1315 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1317 if (STRICT_ALIGNMENT)
1318 warning ("packed attribute causes inefficient alignment for `%s'", name);
1320 warning ("packed attribute is unnecessary for `%s'", name);
1324 if (STRICT_ALIGNMENT)
1325 warning ("packed attribute causes inefficient alignment");
1327 warning ("packed attribute is unnecessary");
1333 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1336 compute_record_mode (type)
1340 enum machine_mode mode = VOIDmode;
1342 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1343 However, if possible, we use a mode that fits in a register
1344 instead, in order to allow for better optimization down the
1346 TYPE_MODE (type) = BLKmode;
1348 if (! host_integerp (TYPE_SIZE (type), 1))
1351 /* A record which has any BLKmode members must itself be
1352 BLKmode; it can't go in a register. Unless the member is
1353 BLKmode only because it isn't aligned. */
1354 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1356 unsigned HOST_WIDE_INT bitpos;
1358 if (TREE_CODE (field) != FIELD_DECL)
1361 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1362 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1363 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
1364 || ! host_integerp (bit_position (field), 1)
1365 || DECL_SIZE (field) == 0
1366 || ! host_integerp (DECL_SIZE (field), 1))
1369 bitpos = int_bit_position (field);
1371 /* Must be BLKmode if any field crosses a word boundary,
1372 since extract_bit_field can't handle that in registers. */
1373 if (bitpos / BITS_PER_WORD
1374 != ((tree_low_cst (DECL_SIZE (field), 1) + bitpos - 1)
1376 /* But there is no problem if the field is entire words. */
1377 && tree_low_cst (DECL_SIZE (field), 1) % BITS_PER_WORD != 0)
1380 /* If this field is the whole struct, remember its mode so
1381 that, say, we can put a double in a class into a DF
1382 register instead of forcing it to live in the stack. */
1383 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1384 mode = DECL_MODE (field);
1386 #ifdef MEMBER_TYPE_FORCES_BLK
1387 /* With some targets, eg. c4x, it is sub-optimal
1388 to access an aligned BLKmode structure as a scalar. */
1390 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1392 #endif /* MEMBER_TYPE_FORCES_BLK */
1395 /* If we only have one real field; use its mode. This only applies to
1396 RECORD_TYPE. This does not apply to unions. */
1397 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1398 TYPE_MODE (type) = mode;
1400 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1402 /* If structure's known alignment is less than what the scalar
1403 mode would need, and it matters, then stick with BLKmode. */
1404 if (TYPE_MODE (type) != BLKmode
1406 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1407 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1409 /* If this is the only reason this type is BLKmode, then
1410 don't force containing types to be BLKmode. */
1411 TYPE_NO_FORCE_BLK (type) = 1;
1412 TYPE_MODE (type) = BLKmode;
1416 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1420 finalize_type_size (type)
1423 /* Normally, use the alignment corresponding to the mode chosen.
1424 However, where strict alignment is not required, avoid
1425 over-aligning structures, since most compilers do not do this
1428 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1429 && (STRICT_ALIGNMENT
1430 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1431 && TREE_CODE (type) != QUAL_UNION_TYPE
1432 && TREE_CODE (type) != ARRAY_TYPE)))
1434 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1435 TYPE_USER_ALIGN (type) = 0;
1438 /* Do machine-dependent extra alignment. */
1439 #ifdef ROUND_TYPE_ALIGN
1441 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1444 /* If we failed to find a simple way to calculate the unit size
1445 of the type, find it by division. */
1446 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1447 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1448 result will fit in sizetype. We will get more efficient code using
1449 sizetype, so we force a conversion. */
1450 TYPE_SIZE_UNIT (type)
1451 = convert (sizetype,
1452 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1453 bitsize_unit_node));
1455 if (TYPE_SIZE (type) != 0)
1457 #ifdef ROUND_TYPE_SIZE
1459 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1460 TYPE_SIZE_UNIT (type)
1461 = ROUND_TYPE_SIZE_UNIT (type, TYPE_SIZE_UNIT (type),
1462 TYPE_ALIGN (type) / BITS_PER_UNIT);
1464 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1465 TYPE_SIZE_UNIT (type)
1466 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1470 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1471 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1472 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1473 if (TYPE_SIZE_UNIT (type) != 0
1474 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1475 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1477 /* Also layout any other variants of the type. */
1478 if (TYPE_NEXT_VARIANT (type)
1479 || type != TYPE_MAIN_VARIANT (type))
1482 /* Record layout info of this variant. */
1483 tree size = TYPE_SIZE (type);
1484 tree size_unit = TYPE_SIZE_UNIT (type);
1485 unsigned int align = TYPE_ALIGN (type);
1486 unsigned int user_align = TYPE_USER_ALIGN (type);
1487 enum machine_mode mode = TYPE_MODE (type);
1489 /* Copy it into all variants. */
1490 for (variant = TYPE_MAIN_VARIANT (type);
1492 variant = TYPE_NEXT_VARIANT (variant))
1494 TYPE_SIZE (variant) = size;
1495 TYPE_SIZE_UNIT (variant) = size_unit;
1496 TYPE_ALIGN (variant) = align;
1497 TYPE_USER_ALIGN (variant) = user_align;
1498 TYPE_MODE (variant) = mode;
1503 /* Do all of the work required to layout the type indicated by RLI,
1504 once the fields have been laid out. This function will call `free'
1505 for RLI, unless FREE_P is false. Passing a value other than false
1506 for FREE_P is bad practice; this option only exists to support the
1510 finish_record_layout (rli, free_p)
1511 record_layout_info rli;
1514 /* Compute the final size. */
1515 finalize_record_size (rli);
1517 /* Compute the TYPE_MODE for the record. */
1518 compute_record_mode (rli->t);
1520 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1521 finalize_type_size (rli->t);
1523 /* Lay out any static members. This is done now because their type
1524 may use the record's type. */
1525 while (rli->pending_statics)
1527 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1528 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1537 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1538 NAME, its fields are chained in reverse on FIELDS.
1540 If ALIGN_TYPE is non-null, it is given the same alignment as
1544 finish_builtin_struct (type, name, fields, align_type)
1552 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1554 DECL_FIELD_CONTEXT (fields) = type;
1555 next = TREE_CHAIN (fields);
1556 TREE_CHAIN (fields) = tail;
1558 TYPE_FIELDS (type) = tail;
1562 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1563 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1567 #if 0 /* not yet, should get fixed properly later */
1568 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1570 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1572 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1573 layout_decl (TYPE_NAME (type), 0);
1576 /* Calculate the mode, size, and alignment for TYPE.
1577 For an array type, calculate the element separation as well.
1578 Record TYPE on the chain of permanent or temporary types
1579 so that dbxout will find out about it.
1581 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1582 layout_type does nothing on such a type.
1584 If the type is incomplete, its TYPE_SIZE remains zero. */
1593 /* Do nothing if type has been laid out before. */
1594 if (TYPE_SIZE (type))
1597 switch (TREE_CODE (type))
1600 /* This kind of type is the responsibility
1601 of the language-specific code. */
1604 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1605 if (TYPE_PRECISION (type) == 0)
1606 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1608 /* ... fall through ... */
1613 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1614 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1615 TREE_UNSIGNED (type) = 1;
1617 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1619 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1620 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1624 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1625 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1626 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1630 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1632 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1633 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1634 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1636 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1637 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1644 subtype = TREE_TYPE (type);
1645 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1646 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1647 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1652 /* This is an incomplete type and so doesn't have a size. */
1653 TYPE_ALIGN (type) = 1;
1654 TYPE_USER_ALIGN (type) = 0;
1655 TYPE_MODE (type) = VOIDmode;
1659 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1660 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1661 /* A pointer might be MODE_PARTIAL_INT,
1662 but ptrdiff_t must be integral. */
1663 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1668 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1669 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1670 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1674 case REFERENCE_TYPE:
1677 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1678 && reference_types_internal)
1679 ? Pmode : TYPE_MODE (type));
1681 int nbits = GET_MODE_BITSIZE (mode);
1683 TYPE_SIZE (type) = bitsize_int (nbits);
1684 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1685 TREE_UNSIGNED (type) = 1;
1686 TYPE_PRECISION (type) = nbits;
1692 tree index = TYPE_DOMAIN (type);
1693 tree element = TREE_TYPE (type);
1695 build_pointer_type (element);
1697 /* We need to know both bounds in order to compute the size. */
1698 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1699 && TYPE_SIZE (element))
1701 tree ub = TYPE_MAX_VALUE (index);
1702 tree lb = TYPE_MIN_VALUE (index);
1706 /* The initial subtraction should happen in the original type so
1707 that (possible) negative values are handled appropriately. */
1708 length = size_binop (PLUS_EXPR, size_one_node,
1710 fold (build (MINUS_EXPR,
1714 /* Special handling for arrays of bits (for Chill). */
1715 element_size = TYPE_SIZE (element);
1716 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1717 && (integer_zerop (TYPE_MAX_VALUE (element))
1718 || integer_onep (TYPE_MAX_VALUE (element)))
1719 && host_integerp (TYPE_MIN_VALUE (element), 1))
1721 HOST_WIDE_INT maxvalue
1722 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1723 HOST_WIDE_INT minvalue
1724 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1726 if (maxvalue - minvalue == 1
1727 && (maxvalue == 1 || maxvalue == 0))
1728 element_size = integer_one_node;
1731 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1732 convert (bitsizetype, length));
1734 /* If we know the size of the element, calculate the total
1735 size directly, rather than do some division thing below.
1736 This optimization helps Fortran assumed-size arrays
1737 (where the size of the array is determined at runtime)
1739 Note that we can't do this in the case where the size of
1740 the elements is one bit since TYPE_SIZE_UNIT cannot be
1741 set correctly in that case. */
1742 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1743 TYPE_SIZE_UNIT (type)
1744 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1747 /* Now round the alignment and size,
1748 using machine-dependent criteria if any. */
1750 #ifdef ROUND_TYPE_ALIGN
1752 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1754 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1756 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1758 #ifdef ROUND_TYPE_SIZE
1759 if (TYPE_SIZE (type) != 0)
1762 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1764 /* If the rounding changed the size of the type, remove any
1765 pre-calculated TYPE_SIZE_UNIT. */
1766 if (simple_cst_equal (TYPE_SIZE (type), tmp) != 1)
1767 TYPE_SIZE_UNIT (type) = NULL;
1769 TYPE_SIZE (type) = tmp;
1773 TYPE_MODE (type) = BLKmode;
1774 if (TYPE_SIZE (type) != 0
1775 #ifdef MEMBER_TYPE_FORCES_BLK
1776 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1778 /* BLKmode elements force BLKmode aggregate;
1779 else extract/store fields may lose. */
1780 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1781 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1783 /* One-element arrays get the component type's mode. */
1784 if (simple_cst_equal (TYPE_SIZE (type),
1785 TYPE_SIZE (TREE_TYPE (type))))
1786 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1789 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1791 if (TYPE_MODE (type) != BLKmode
1792 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1793 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1794 && TYPE_MODE (type) != BLKmode)
1796 TYPE_NO_FORCE_BLK (type) = 1;
1797 TYPE_MODE (type) = BLKmode;
1805 case QUAL_UNION_TYPE:
1808 record_layout_info rli;
1810 /* Initialize the layout information. */
1811 rli = start_record_layout (type);
1813 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1814 in the reverse order in building the COND_EXPR that denotes
1815 its size. We reverse them again later. */
1816 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1817 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1819 /* Place all the fields. */
1820 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1821 place_field (rli, field);
1823 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1824 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1826 if (lang_adjust_rli)
1827 (*lang_adjust_rli) (rli);
1829 /* Finish laying out the record. */
1830 finish_record_layout (rli, /*free_p=*/true);
1834 case SET_TYPE: /* Used by Chill and Pascal. */
1835 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1836 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1840 #ifndef SET_WORD_SIZE
1841 #define SET_WORD_SIZE BITS_PER_WORD
1843 unsigned int alignment
1844 = set_alignment ? set_alignment : SET_WORD_SIZE;
1846 = (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
1847 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1);
1849 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1851 if (rounded_size > (int) alignment)
1852 TYPE_MODE (type) = BLKmode;
1854 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1856 TYPE_SIZE (type) = bitsize_int (rounded_size);
1857 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1858 TYPE_ALIGN (type) = alignment;
1859 TYPE_USER_ALIGN (type) = 0;
1860 TYPE_PRECISION (type) = size_in_bits;
1865 /* The size may vary in different languages, so the language front end
1866 should fill in the size. */
1867 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1868 TYPE_USER_ALIGN (type) = 0;
1869 TYPE_MODE (type) = BLKmode;
1876 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1877 records and unions, finish_record_layout already called this
1879 if (TREE_CODE (type) != RECORD_TYPE
1880 && TREE_CODE (type) != UNION_TYPE
1881 && TREE_CODE (type) != QUAL_UNION_TYPE)
1882 finalize_type_size (type);
1884 /* If this type is created before sizetype has been permanently set,
1885 record it so set_sizetype can fix it up. */
1887 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1889 /* If an alias set has been set for this aggregate when it was incomplete,
1890 force it into alias set 0.
1891 This is too conservative, but we cannot call record_component_aliases
1892 here because some frontends still change the aggregates after
1894 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1895 TYPE_ALIAS_SET (type) = 0;
1898 /* Create and return a type for signed integers of PRECISION bits. */
1901 make_signed_type (precision)
1904 tree type = make_node (INTEGER_TYPE);
1906 TYPE_PRECISION (type) = precision;
1908 fixup_signed_type (type);
1912 /* Create and return a type for unsigned integers of PRECISION bits. */
1915 make_unsigned_type (precision)
1918 tree type = make_node (INTEGER_TYPE);
1920 TYPE_PRECISION (type) = precision;
1922 fixup_unsigned_type (type);
1926 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1927 value to enable integer types to be created. */
1930 initialize_sizetypes ()
1932 tree t = make_node (INTEGER_TYPE);
1934 /* Set this so we do something reasonable for the build_int_2 calls
1936 integer_type_node = t;
1938 TYPE_MODE (t) = SImode;
1939 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1940 TYPE_USER_ALIGN (t) = 0;
1941 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1942 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1943 TREE_UNSIGNED (t) = 1;
1944 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1945 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1946 TYPE_IS_SIZETYPE (t) = 1;
1948 /* 1000 avoids problems with possible overflow and is certainly
1949 larger than any size value we'd want to be storing. */
1950 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1952 /* These two must be different nodes because of the caching done in
1955 bitsizetype = copy_node (t);
1956 integer_type_node = 0;
1959 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1960 Also update the type of any standard type's sizes made so far. */
1966 int oprecision = TYPE_PRECISION (type);
1967 /* The *bitsizetype types use a precision that avoids overflows when
1968 calculating signed sizes / offsets in bits. However, when
1969 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1971 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1972 2 * HOST_BITS_PER_WIDE_INT);
1979 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1980 sizetype = copy_node (type);
1981 TYPE_DOMAIN (sizetype) = type;
1982 TYPE_IS_SIZETYPE (sizetype) = 1;
1983 bitsizetype = make_node (INTEGER_TYPE);
1984 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1985 TYPE_PRECISION (bitsizetype) = precision;
1986 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1988 if (TREE_UNSIGNED (type))
1989 fixup_unsigned_type (bitsizetype);
1991 fixup_signed_type (bitsizetype);
1993 layout_type (bitsizetype);
1995 if (TREE_UNSIGNED (type))
1997 usizetype = sizetype;
1998 ubitsizetype = bitsizetype;
1999 ssizetype = copy_node (make_signed_type (oprecision));
2000 sbitsizetype = copy_node (make_signed_type (precision));
2004 ssizetype = sizetype;
2005 sbitsizetype = bitsizetype;
2006 usizetype = copy_node (make_unsigned_type (oprecision));
2007 ubitsizetype = copy_node (make_unsigned_type (precision));
2010 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
2012 /* Show is a sizetype, is a main type, and has no pointers to it. */
2013 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
2015 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
2016 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
2017 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
2018 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
2019 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
2022 /* Go down each of the types we already made and set the proper type
2023 for the sizes in them. */
2024 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
2026 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE)
2029 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
2030 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
2033 early_type_list = 0;
2037 /* Set the extreme values of TYPE based on its precision in bits,
2038 then lay it out. Used when make_signed_type won't do
2039 because the tree code is not INTEGER_TYPE.
2040 E.g. for Pascal, when the -fsigned-char option is given. */
2043 fixup_signed_type (type)
2046 int precision = TYPE_PRECISION (type);
2048 /* We can not represent properly constants greater then
2049 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2050 as they are used by i386 vector extensions and friends. */
2051 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2052 precision = HOST_BITS_PER_WIDE_INT * 2;
2054 TYPE_MIN_VALUE (type)
2055 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2056 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
2057 (((HOST_WIDE_INT) (-1)
2058 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2059 ? precision - HOST_BITS_PER_WIDE_INT - 1
2061 TYPE_MAX_VALUE (type)
2062 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2063 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2064 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2065 ? (((HOST_WIDE_INT) 1
2066 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2069 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2070 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2072 /* Lay out the type: set its alignment, size, etc. */
2076 /* Set the extreme values of TYPE based on its precision in bits,
2077 then lay it out. This is used both in `make_unsigned_type'
2078 and for enumeral types. */
2081 fixup_unsigned_type (type)
2084 int precision = TYPE_PRECISION (type);
2086 /* We can not represent properly constants greater then
2087 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2088 as they are used by i386 vector extensions and friends. */
2089 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2090 precision = HOST_BITS_PER_WIDE_INT * 2;
2092 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
2093 TYPE_MAX_VALUE (type)
2094 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
2095 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
2096 precision - HOST_BITS_PER_WIDE_INT > 0
2097 ? ((unsigned HOST_WIDE_INT) ~0
2098 >> (HOST_BITS_PER_WIDE_INT
2099 - (precision - HOST_BITS_PER_WIDE_INT)))
2101 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2102 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2104 /* Lay out the type: set its alignment, size, etc. */
2108 /* Find the best machine mode to use when referencing a bit field of length
2109 BITSIZE bits starting at BITPOS.
2111 The underlying object is known to be aligned to a boundary of ALIGN bits.
2112 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2113 larger than LARGEST_MODE (usually SImode).
2115 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2116 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2117 mode meeting these conditions.
2119 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2120 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2121 all the conditions. */
2124 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
2125 int bitsize, bitpos;
2127 enum machine_mode largest_mode;
2130 enum machine_mode mode;
2131 unsigned int unit = 0;
2133 /* Find the narrowest integer mode that contains the bit field. */
2134 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2135 mode = GET_MODE_WIDER_MODE (mode))
2137 unit = GET_MODE_BITSIZE (mode);
2138 if ((bitpos % unit) + bitsize <= unit)
2142 if (mode == VOIDmode
2143 /* It is tempting to omit the following line
2144 if STRICT_ALIGNMENT is true.
2145 But that is incorrect, since if the bitfield uses part of 3 bytes
2146 and we use a 4-byte mode, we could get a spurious segv
2147 if the extra 4th byte is past the end of memory.
2148 (Though at least one Unix compiler ignores this problem:
2149 that on the Sequent 386 machine. */
2150 || MIN (unit, BIGGEST_ALIGNMENT) > align
2151 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2154 if (SLOW_BYTE_ACCESS && ! volatilep)
2156 enum machine_mode wide_mode = VOIDmode, tmode;
2158 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2159 tmode = GET_MODE_WIDER_MODE (tmode))
2161 unit = GET_MODE_BITSIZE (tmode);
2162 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2163 && unit <= BITS_PER_WORD
2164 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2165 && (largest_mode == VOIDmode
2166 || unit <= GET_MODE_BITSIZE (largest_mode)))
2170 if (wide_mode != VOIDmode)
2177 #include "gt-stor-layout.h"