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 (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 static unsigned int update_alignment_for_field (record_layout_info, tree,
71 extern void debug_rli (record_layout_info);
73 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
75 static GTY(()) tree pending_sizes;
77 /* Nonzero means cannot safely call expand_expr now,
78 so put variable sizes onto `pending_sizes' instead. */
80 int immediate_size_expand;
82 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
86 internal_reference_types (void)
88 reference_types_internal = 1;
91 /* Get a list of all the objects put on the pending sizes list. */
94 get_pending_sizes (void)
96 tree chain = pending_sizes;
99 /* Put each SAVE_EXPR into the current function. */
100 for (t = chain; t; t = TREE_CHAIN (t))
101 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
107 /* Return nonzero if EXPR is present on the pending sizes list. */
110 is_pending_size (tree expr)
114 for (t = pending_sizes; t; t = TREE_CHAIN (t))
115 if (TREE_VALUE (t) == expr)
120 /* Add EXPR to the pending sizes list. */
123 put_pending_size (tree expr)
125 /* Strip any simple arithmetic from EXPR to see if it has an underlying
127 expr = skip_simple_arithmetic (expr);
129 if (TREE_CODE (expr) == SAVE_EXPR)
130 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
133 /* Put a chain of objects into the pending sizes list, which must be
137 put_pending_sizes (tree chain)
142 pending_sizes = chain;
145 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
146 to serve as the actual size-expression for a type or decl. */
149 variable_size (tree size)
153 /* If the language-processor is to take responsibility for variable-sized
154 items (e.g., languages which have elaboration procedures like Ada),
155 just return SIZE unchanged. Likewise for self-referential sizes and
157 if (TREE_CONSTANT (size)
158 || (*lang_hooks.decls.global_bindings_p) () < 0
159 || CONTAINS_PLACEHOLDER_P (size))
162 if (TREE_CODE (size) == MINUS_EXPR && integer_onep (TREE_OPERAND (size, 1)))
163 /* If this is the upper bound of a C array, leave the minus 1 outside
164 the SAVE_EXPR so it can be folded away. */
165 TREE_OPERAND (size, 0) = save = save_expr (TREE_OPERAND (size, 0));
167 size = save = save_expr (size);
169 /* If an array with a variable number of elements is declared, and
170 the elements require destruction, we will emit a cleanup for the
171 array. That cleanup is run both on normal exit from the block
172 and in the exception-handler for the block. Normally, when code
173 is used in both ordinary code and in an exception handler it is
174 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
175 not wish to do that here; the array-size is the same in both
177 if (TREE_CODE (save) == SAVE_EXPR)
178 SAVE_EXPR_PERSISTENT_P (save) = 1;
180 if ((*lang_hooks.decls.global_bindings_p) ())
182 if (TREE_CONSTANT (size))
183 error ("type size can't be explicitly evaluated");
185 error ("variable-size type declared outside of any function");
187 return size_one_node;
190 if (immediate_size_expand)
191 expand_expr (save, const0_rtx, VOIDmode, 0);
192 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
193 /* The front-end doesn't want us to keep a list of the expressions
194 that determine sizes for variable size objects. */
197 put_pending_size (save);
202 #ifndef MAX_FIXED_MODE_SIZE
203 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
206 /* Return the machine mode to use for a nonscalar of SIZE bits.
207 The mode must be in class CLASS, and have exactly that many bits.
208 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
212 mode_for_size (unsigned int size, enum mode_class class, int limit)
214 enum machine_mode mode;
216 if (limit && size > MAX_FIXED_MODE_SIZE)
219 /* Get the first mode which has this size, in the specified class. */
220 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
221 mode = GET_MODE_WIDER_MODE (mode))
222 if (GET_MODE_BITSIZE (mode) == size)
228 /* Similar, except passed a tree node. */
231 mode_for_size_tree (tree size, enum mode_class class, int limit)
233 if (TREE_CODE (size) != INTEGER_CST
234 || TREE_OVERFLOW (size)
235 /* What we really want to say here is that the size can fit in a
236 host integer, but we know there's no way we'd find a mode for
237 this many bits, so there's no point in doing the precise test. */
238 || compare_tree_int (size, 1000) > 0)
241 return mode_for_size (tree_low_cst (size, 1), class, limit);
244 /* Similar, but never return BLKmode; return the narrowest mode that
245 contains at least the requested number of bits. */
248 smallest_mode_for_size (unsigned int size, enum mode_class class)
250 enum machine_mode mode;
252 /* Get the first mode which has at least this size, in the
254 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
255 mode = GET_MODE_WIDER_MODE (mode))
256 if (GET_MODE_BITSIZE (mode) >= size)
262 /* Find an integer mode of the exact same size, or BLKmode on failure. */
265 int_mode_for_mode (enum machine_mode mode)
267 switch (GET_MODE_CLASS (mode))
270 case MODE_PARTIAL_INT:
273 case MODE_COMPLEX_INT:
274 case MODE_COMPLEX_FLOAT:
276 case MODE_VECTOR_INT:
277 case MODE_VECTOR_FLOAT:
278 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
285 /* ... fall through ... */
295 /* Return the alignment of MODE. This will be bounded by 1 and
296 BIGGEST_ALIGNMENT. */
299 get_mode_alignment (enum machine_mode mode)
301 return MIN (BIGGEST_ALIGNMENT, MAX (1, mode_base_align[mode]*BITS_PER_UNIT));
304 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
305 This can only be applied to objects of a sizetype. */
308 round_up (tree value, int divisor)
310 tree arg = size_int_type (divisor, TREE_TYPE (value));
312 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
315 /* Likewise, but round down. */
318 round_down (tree value, int divisor)
320 tree arg = size_int_type (divisor, TREE_TYPE (value));
322 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
325 /* Subroutine of layout_decl: Force alignment required for the data type.
326 But if the decl itself wants greater alignment, don't override that. */
329 do_type_align (tree type, tree decl)
331 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
333 DECL_ALIGN (decl) = TYPE_ALIGN (type);
334 if (TREE_CODE (decl) == FIELD_DECL)
335 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
339 /* Set the size, mode and alignment of a ..._DECL node.
340 TYPE_DECL does need this for C++.
341 Note that LABEL_DECL and CONST_DECL nodes do not need this,
342 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
343 Don't call layout_decl for them.
345 KNOWN_ALIGN is the amount of alignment we can assume this
346 decl has with no special effort. It is relevant only for FIELD_DECLs
347 and depends on the previous fields.
348 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
349 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
350 the record will be aligned to suit. */
353 layout_decl (tree decl, unsigned int known_align)
355 tree type = TREE_TYPE (decl);
356 enum tree_code code = TREE_CODE (decl);
359 if (code == CONST_DECL)
361 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
362 && code != TYPE_DECL && code != FIELD_DECL)
365 rtl = DECL_RTL_IF_SET (decl);
367 if (type == error_mark_node)
368 type = void_type_node;
370 /* Usually the size and mode come from the data type without change,
371 however, the front-end may set the explicit width of the field, so its
372 size may not be the same as the size of its type. This happens with
373 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
374 also happens with other fields. For example, the C++ front-end creates
375 zero-sized fields corresponding to empty base classes, and depends on
376 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
377 size in bytes from the size in bits. If we have already set the mode,
378 don't set it again since we can be called twice for FIELD_DECLs. */
380 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
381 if (DECL_MODE (decl) == VOIDmode)
382 DECL_MODE (decl) = TYPE_MODE (type);
384 if (DECL_SIZE (decl) == 0)
386 DECL_SIZE (decl) = TYPE_SIZE (type);
387 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
389 else if (DECL_SIZE_UNIT (decl) == 0)
390 DECL_SIZE_UNIT (decl)
391 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
394 if (code != FIELD_DECL)
395 /* For non-fields, update the alignment from the type. */
396 do_type_align (type, decl);
398 /* For fields, it's a bit more complicated... */
400 if (DECL_BIT_FIELD (decl))
402 DECL_BIT_FIELD_TYPE (decl) = type;
404 /* A zero-length bit-field affects the alignment of the next
406 if (integer_zerop (DECL_SIZE (decl))
407 && ! DECL_PACKED (decl)
408 && ! (*targetm.ms_bitfield_layout_p) (DECL_FIELD_CONTEXT (decl)))
410 #ifdef PCC_BITFIELD_TYPE_MATTERS
411 if (PCC_BITFIELD_TYPE_MATTERS)
412 do_type_align (type, decl);
416 #ifdef EMPTY_FIELD_BOUNDARY
417 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
419 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
420 DECL_USER_ALIGN (decl) = 0;
426 /* See if we can use an ordinary integer mode for a bit-field.
427 Conditions are: a fixed size that is correct for another mode
428 and occupying a complete byte or bytes on proper boundary. */
429 if (TYPE_SIZE (type) != 0
430 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
431 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
433 enum machine_mode xmode
434 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
436 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
438 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
440 DECL_MODE (decl) = xmode;
441 DECL_BIT_FIELD (decl) = 0;
445 /* Turn off DECL_BIT_FIELD if we won't need it set. */
446 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
447 && known_align >= TYPE_ALIGN (type)
448 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
449 DECL_BIT_FIELD (decl) = 0;
451 else if (DECL_PACKED (decl) && DECL_USER_ALIGN (decl))
452 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
453 round up; we'll reduce it again below. We want packing to
454 supercede USER_ALIGN inherited from the type, but defer to
455 alignment explicitly specified on the field decl. */;
458 do_type_align (type, decl);
460 /* If the field is of variable size, we can't misalign it since we
461 have no way to make a temporary to align the result. But this
462 isn't an issue if the decl is not addressable. Likewise if it
465 Note that do_type_align may set DECL_USER_ALIGN, so we don't
466 want to check it again here. */
467 if (DECL_PACKED (decl)
468 && (DECL_NONADDRESSABLE_P (decl)
469 || DECL_SIZE_UNIT (decl) == 0
470 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
471 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
474 /* Should this be controlled by DECL_USER_ALIGN, too? */
475 if (maximum_field_alignment != 0)
476 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
477 if (! DECL_USER_ALIGN (decl))
479 /* Some targets (i.e. i386, VMS) limit struct field alignment
480 to a lower boundary than alignment of variables unless
481 it was overridden by attribute aligned. */
482 #ifdef BIGGEST_FIELD_ALIGNMENT
484 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
486 #ifdef ADJUST_FIELD_ALIGN
487 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
492 /* Evaluate nonconstant size only once, either now or as soon as safe. */
493 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
494 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
495 if (DECL_SIZE_UNIT (decl) != 0
496 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
497 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
499 /* If requested, warn about definitions of large data objects. */
501 && (code == VAR_DECL || code == PARM_DECL)
502 && ! DECL_EXTERNAL (decl))
504 tree size = DECL_SIZE_UNIT (decl);
506 if (size != 0 && TREE_CODE (size) == INTEGER_CST
507 && compare_tree_int (size, larger_than_size) > 0)
509 int size_as_int = TREE_INT_CST_LOW (size);
511 if (compare_tree_int (size, size_as_int) == 0)
512 warning ("%Jsize of '%D' is %d bytes", decl, decl, size_as_int);
514 warning ("%Jsize of '%D' is larger than %d bytes",
515 decl, decl, larger_than_size);
519 /* If the RTL was already set, update its mode and mem attributes. */
522 PUT_MODE (rtl, DECL_MODE (decl));
523 SET_DECL_RTL (decl, 0);
524 set_mem_attributes (rtl, decl, 1);
525 SET_DECL_RTL (decl, rtl);
529 /* Hook for a front-end function that can modify the record layout as needed
530 immediately before it is finalized. */
532 void (*lang_adjust_rli) (record_layout_info) = 0;
535 set_lang_adjust_rli (void (*f) (record_layout_info))
540 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
541 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
542 is to be passed to all other layout functions for this record. It is the
543 responsibility of the caller to call `free' for the storage returned.
544 Note that garbage collection is not permitted until we finish laying
548 start_record_layout (tree t)
550 record_layout_info rli = xmalloc (sizeof (struct record_layout_info_s));
554 /* If the type has a minimum specified alignment (via an attribute
555 declaration, for example) use it -- otherwise, start with a
556 one-byte alignment. */
557 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
558 rli->unpacked_align = rli->record_align;
559 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
561 #ifdef STRUCTURE_SIZE_BOUNDARY
562 /* Packed structures don't need to have minimum size. */
563 if (! TYPE_PACKED (t))
564 rli->record_align = MAX (rli->record_align, (unsigned) STRUCTURE_SIZE_BOUNDARY);
567 rli->offset = size_zero_node;
568 rli->bitpos = bitsize_zero_node;
570 rli->pending_statics = 0;
571 rli->packed_maybe_necessary = 0;
576 /* These four routines perform computations that convert between
577 the offset/bitpos forms and byte and bit offsets. */
580 bit_from_pos (tree offset, tree bitpos)
582 return size_binop (PLUS_EXPR, bitpos,
583 size_binop (MULT_EXPR, convert (bitsizetype, offset),
588 byte_from_pos (tree offset, tree bitpos)
590 return size_binop (PLUS_EXPR, offset,
592 size_binop (TRUNC_DIV_EXPR, bitpos,
593 bitsize_unit_node)));
597 pos_from_bit (tree *poffset, tree *pbitpos, unsigned int off_align,
600 *poffset = size_binop (MULT_EXPR,
602 size_binop (FLOOR_DIV_EXPR, pos,
603 bitsize_int (off_align))),
604 size_int (off_align / BITS_PER_UNIT));
605 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
608 /* Given a pointer to bit and byte offsets and an offset alignment,
609 normalize the offsets so they are within the alignment. */
612 normalize_offset (tree *poffset, tree *pbitpos, unsigned int off_align)
614 /* If the bit position is now larger than it should be, adjust it
616 if (compare_tree_int (*pbitpos, off_align) >= 0)
618 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
619 bitsize_int (off_align));
622 = size_binop (PLUS_EXPR, *poffset,
623 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
624 size_int (off_align / BITS_PER_UNIT)));
627 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
631 /* Print debugging information about the information in RLI. */
634 debug_rli (record_layout_info rli)
636 print_node_brief (stderr, "type", rli->t, 0);
637 print_node_brief (stderr, "\noffset", rli->offset, 0);
638 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
640 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
641 rli->record_align, rli->unpacked_align,
643 if (rli->packed_maybe_necessary)
644 fprintf (stderr, "packed may be necessary\n");
646 if (rli->pending_statics)
648 fprintf (stderr, "pending statics:\n");
649 debug_tree (rli->pending_statics);
653 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
654 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
657 normalize_rli (record_layout_info rli)
659 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
662 /* Returns the size in bytes allocated so far. */
665 rli_size_unit_so_far (record_layout_info rli)
667 return byte_from_pos (rli->offset, rli->bitpos);
670 /* Returns the size in bits allocated so far. */
673 rli_size_so_far (record_layout_info rli)
675 return bit_from_pos (rli->offset, rli->bitpos);
678 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
679 the next available location is given by KNOWN_ALIGN. Update the
680 variable alignment fields in RLI, and return the alignment to give
684 update_alignment_for_field (record_layout_info rli, tree field,
685 unsigned int known_align)
687 /* The alignment required for FIELD. */
688 unsigned int desired_align;
689 /* The type of this field. */
690 tree type = TREE_TYPE (field);
691 /* True if the field was explicitly aligned by the user. */
695 /* Lay out the field so we know what alignment it needs. */
696 layout_decl (field, known_align);
697 desired_align = DECL_ALIGN (field);
698 user_align = DECL_USER_ALIGN (field);
700 is_bitfield = (type != error_mark_node
701 && DECL_BIT_FIELD_TYPE (field)
702 && ! integer_zerop (TYPE_SIZE (type)));
704 /* Record must have at least as much alignment as any field.
705 Otherwise, the alignment of the field within the record is
707 if (is_bitfield && (* targetm.ms_bitfield_layout_p) (rli->t))
709 /* Here, the alignment of the underlying type of a bitfield can
710 affect the alignment of a record; even a zero-sized field
711 can do this. The alignment should be to the alignment of
712 the type, except that for zero-size bitfields this only
713 applies if there was an immediately prior, nonzero-size
714 bitfield. (That's the way it is, experimentally.) */
715 if (! integer_zerop (DECL_SIZE (field))
716 ? ! DECL_PACKED (field)
718 && DECL_BIT_FIELD_TYPE (rli->prev_field)
719 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
721 unsigned int type_align = TYPE_ALIGN (type);
722 type_align = MAX (type_align, desired_align);
723 if (maximum_field_alignment != 0)
724 type_align = MIN (type_align, maximum_field_alignment);
725 rli->record_align = MAX (rli->record_align, type_align);
726 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
729 #ifdef PCC_BITFIELD_TYPE_MATTERS
730 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
732 /* Named bit-fields cause the entire structure to have the
733 alignment implied by their type. */
734 if (DECL_NAME (field) != 0)
736 unsigned int type_align = TYPE_ALIGN (type);
738 #ifdef ADJUST_FIELD_ALIGN
739 if (! TYPE_USER_ALIGN (type))
740 type_align = ADJUST_FIELD_ALIGN (field, type_align);
743 if (maximum_field_alignment != 0)
744 type_align = MIN (type_align, maximum_field_alignment);
745 else if (DECL_PACKED (field))
746 type_align = MIN (type_align, BITS_PER_UNIT);
748 /* The alignment of the record is increased to the maximum
749 of the current alignment, the alignment indicated on the
750 field (i.e., the alignment specified by an __aligned__
751 attribute), and the alignment indicated by the type of
753 rli->record_align = MAX (rli->record_align, desired_align);
754 rli->record_align = MAX (rli->record_align, type_align);
757 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
758 user_align |= TYPE_USER_ALIGN (type);
764 rli->record_align = MAX (rli->record_align, desired_align);
765 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
768 TYPE_USER_ALIGN (rli->t) |= user_align;
770 return desired_align;
773 /* Called from place_field to handle unions. */
776 place_union_field (record_layout_info rli, tree field)
778 update_alignment_for_field (rli, field, /*known_align=*/0);
780 DECL_FIELD_OFFSET (field) = size_zero_node;
781 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
782 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
784 /* We assume the union's size will be a multiple of a byte so we don't
785 bother with BITPOS. */
786 if (TREE_CODE (rli->t) == UNION_TYPE)
787 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
788 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
789 rli->offset = fold (build (COND_EXPR, sizetype,
790 DECL_QUALIFIER (field),
791 DECL_SIZE_UNIT (field), rli->offset));
794 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
795 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
796 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
797 units of alignment than the underlying TYPE. */
799 excess_unit_span (HOST_WIDE_INT byte_offset, HOST_WIDE_INT bit_offset,
800 HOST_WIDE_INT size, HOST_WIDE_INT align, tree type)
802 /* Note that the calculation of OFFSET might overflow; we calculate it so
803 that we still get the right result as long as ALIGN is a power of two. */
804 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
806 offset = offset % align;
807 return ((offset + size + align - 1) / align
808 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
813 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
814 is a FIELD_DECL to be added after those fields already present in
815 T. (FIELD is not actually added to the TYPE_FIELDS list here;
816 callers that desire that behavior must manually perform that step.) */
819 place_field (record_layout_info rli, tree field)
821 /* The alignment required for FIELD. */
822 unsigned int desired_align;
823 /* The alignment FIELD would have if we just dropped it into the
824 record as it presently stands. */
825 unsigned int known_align;
826 unsigned int actual_align;
827 /* The type of this field. */
828 tree type = TREE_TYPE (field);
830 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
833 /* If FIELD is static, then treat it like a separate variable, not
834 really like a structure field. If it is a FUNCTION_DECL, it's a
835 method. In both cases, all we do is lay out the decl, and we do
836 it *after* the record is laid out. */
837 if (TREE_CODE (field) == VAR_DECL)
839 rli->pending_statics = tree_cons (NULL_TREE, field,
840 rli->pending_statics);
844 /* Enumerators and enum types which are local to this class need not
845 be laid out. Likewise for initialized constant fields. */
846 else if (TREE_CODE (field) != FIELD_DECL)
849 /* Unions are laid out very differently than records, so split
850 that code off to another function. */
851 else if (TREE_CODE (rli->t) != RECORD_TYPE)
853 place_union_field (rli, field);
857 /* Work out the known alignment so far. Note that A & (-A) is the
858 value of the least-significant bit in A that is one. */
859 if (! integer_zerop (rli->bitpos))
860 known_align = (tree_low_cst (rli->bitpos, 1)
861 & - tree_low_cst (rli->bitpos, 1));
862 else if (integer_zerop (rli->offset))
863 known_align = BIGGEST_ALIGNMENT;
864 else if (host_integerp (rli->offset, 1))
865 known_align = (BITS_PER_UNIT
866 * (tree_low_cst (rli->offset, 1)
867 & - tree_low_cst (rli->offset, 1)));
869 known_align = rli->offset_align;
871 desired_align = update_alignment_for_field (rli, field, known_align);
873 if (warn_packed && DECL_PACKED (field))
875 if (known_align >= TYPE_ALIGN (type))
877 if (TYPE_ALIGN (type) > desired_align)
879 if (STRICT_ALIGNMENT)
880 warning ("%Jpacked attribute causes inefficient alignment "
881 "for '%D'", field, field);
883 warning ("%Jpacked attribute is unnecessary for '%D'",
888 rli->packed_maybe_necessary = 1;
891 /* Does this field automatically have alignment it needs by virtue
892 of the fields that precede it and the record's own alignment? */
893 if (known_align < desired_align)
895 /* No, we need to skip space before this field.
896 Bump the cumulative size to multiple of field alignment. */
899 warning ("%Jpadding struct to align '%D'", field, field);
901 /* If the alignment is still within offset_align, just align
903 if (desired_align < rli->offset_align)
904 rli->bitpos = round_up (rli->bitpos, desired_align);
907 /* First adjust OFFSET by the partial bits, then align. */
909 = size_binop (PLUS_EXPR, rli->offset,
911 size_binop (CEIL_DIV_EXPR, rli->bitpos,
912 bitsize_unit_node)));
913 rli->bitpos = bitsize_zero_node;
915 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
918 if (! TREE_CONSTANT (rli->offset))
919 rli->offset_align = desired_align;
923 /* Handle compatibility with PCC. Note that if the record has any
924 variable-sized fields, we need not worry about compatibility. */
925 #ifdef PCC_BITFIELD_TYPE_MATTERS
926 if (PCC_BITFIELD_TYPE_MATTERS
927 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
928 && TREE_CODE (field) == FIELD_DECL
929 && type != error_mark_node
930 && DECL_BIT_FIELD (field)
931 && ! DECL_PACKED (field)
932 && maximum_field_alignment == 0
933 && ! integer_zerop (DECL_SIZE (field))
934 && host_integerp (DECL_SIZE (field), 1)
935 && host_integerp (rli->offset, 1)
936 && host_integerp (TYPE_SIZE (type), 1))
938 unsigned int type_align = TYPE_ALIGN (type);
939 tree dsize = DECL_SIZE (field);
940 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
941 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
942 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
944 #ifdef ADJUST_FIELD_ALIGN
945 if (! TYPE_USER_ALIGN (type))
946 type_align = ADJUST_FIELD_ALIGN (field, type_align);
949 /* A bit field may not span more units of alignment of its type
950 than its type itself. Advance to next boundary if necessary. */
951 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
952 rli->bitpos = round_up (rli->bitpos, type_align);
954 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
958 #ifdef BITFIELD_NBYTES_LIMITED
959 if (BITFIELD_NBYTES_LIMITED
960 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
961 && TREE_CODE (field) == FIELD_DECL
962 && type != error_mark_node
963 && DECL_BIT_FIELD_TYPE (field)
964 && ! DECL_PACKED (field)
965 && ! integer_zerop (DECL_SIZE (field))
966 && host_integerp (DECL_SIZE (field), 1)
967 && host_integerp (rli->offset, 1)
968 && host_integerp (TYPE_SIZE (type), 1))
970 unsigned int type_align = TYPE_ALIGN (type);
971 tree dsize = DECL_SIZE (field);
972 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
973 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
974 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
976 #ifdef ADJUST_FIELD_ALIGN
977 if (! TYPE_USER_ALIGN (type))
978 type_align = ADJUST_FIELD_ALIGN (field, type_align);
981 if (maximum_field_alignment != 0)
982 type_align = MIN (type_align, maximum_field_alignment);
983 /* ??? This test is opposite the test in the containing if
984 statement, so this code is unreachable currently. */
985 else if (DECL_PACKED (field))
986 type_align = MIN (type_align, BITS_PER_UNIT);
988 /* A bit field may not span the unit of alignment of its type.
989 Advance to next boundary if necessary. */
990 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
991 rli->bitpos = round_up (rli->bitpos, type_align);
993 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
997 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
999 When a bit field is inserted into a packed record, the whole
1000 size of the underlying type is used by one or more same-size
1001 adjacent bitfields. (That is, if its long:3, 32 bits is
1002 used in the record, and any additional adjacent long bitfields are
1003 packed into the same chunk of 32 bits. However, if the size
1004 changes, a new field of that size is allocated.) In an unpacked
1005 record, this is the same as using alignment, but not equivalent
1008 Note: for compatibility, we use the type size, not the type alignment
1009 to determine alignment, since that matches the documentation */
1011 if ((* targetm.ms_bitfield_layout_p) (rli->t)
1012 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1013 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1015 /* At this point, either the prior or current are bitfields,
1016 (possibly both), and we're dealing with MS packing. */
1017 tree prev_saved = rli->prev_field;
1019 /* Is the prior field a bitfield? If so, handle "runs" of same
1020 type size fields. */
1021 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1023 /* If both are bitfields, nonzero, and the same size, this is
1024 the middle of a run. Zero declared size fields are special
1025 and handled as "end of run". (Note: it's nonzero declared
1026 size, but equal type sizes!) (Since we know that both
1027 the current and previous fields are bitfields by the
1028 time we check it, DECL_SIZE must be present for both.) */
1029 if (DECL_BIT_FIELD_TYPE (field)
1030 && !integer_zerop (DECL_SIZE (field))
1031 && !integer_zerop (DECL_SIZE (rli->prev_field))
1032 && host_integerp (DECL_SIZE (rli->prev_field), 0)
1033 && host_integerp (TYPE_SIZE (type), 0)
1034 && simple_cst_equal (TYPE_SIZE (type),
1035 TYPE_SIZE (TREE_TYPE (rli->prev_field))))
1037 /* We're in the middle of a run of equal type size fields; make
1038 sure we realign if we run out of bits. (Not decl size,
1040 HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 0);
1042 if (rli->remaining_in_alignment < bitsize)
1044 /* out of bits; bump up to next 'word'. */
1045 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1047 = size_binop (PLUS_EXPR, TYPE_SIZE (type),
1048 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1049 rli->prev_field = field;
1050 rli->remaining_in_alignment
1051 = tree_low_cst (TYPE_SIZE (type), 0);
1054 rli->remaining_in_alignment -= bitsize;
1058 /* End of a run: if leaving a run of bitfields of the same type
1059 size, we have to "use up" the rest of the bits of the type
1062 Compute the new position as the sum of the size for the prior
1063 type and where we first started working on that type.
1064 Note: since the beginning of the field was aligned then
1065 of course the end will be too. No round needed. */
1067 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1069 tree type_size = TYPE_SIZE (TREE_TYPE (rli->prev_field));
1072 = size_binop (PLUS_EXPR, type_size,
1073 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1076 /* We "use up" size zero fields; the code below should behave
1077 as if the prior field was not a bitfield. */
1080 /* Cause a new bitfield to be captured, either this time (if
1081 currently a bitfield) or next time we see one. */
1082 if (!DECL_BIT_FIELD_TYPE(field)
1083 || integer_zerop (DECL_SIZE (field)))
1084 rli->prev_field = NULL;
1087 rli->offset_align = tree_low_cst (TYPE_SIZE (type), 0);
1088 normalize_rli (rli);
1091 /* If we're starting a new run of same size type bitfields
1092 (or a run of non-bitfields), set up the "first of the run"
1095 That is, if the current field is not a bitfield, or if there
1096 was a prior bitfield the type sizes differ, or if there wasn't
1097 a prior bitfield the size of the current field is nonzero.
1099 Note: we must be sure to test ONLY the type size if there was
1100 a prior bitfield and ONLY for the current field being zero if
1103 if (!DECL_BIT_FIELD_TYPE (field)
1104 || ( prev_saved != NULL
1105 ? !simple_cst_equal (TYPE_SIZE (type),
1106 TYPE_SIZE (TREE_TYPE (prev_saved)))
1107 : !integer_zerop (DECL_SIZE (field)) ))
1109 /* Never smaller than a byte for compatibility. */
1110 unsigned int type_align = BITS_PER_UNIT;
1112 /* (When not a bitfield), we could be seeing a flex array (with
1113 no DECL_SIZE). Since we won't be using remaining_in_alignment
1114 until we see a bitfield (and come by here again) we just skip
1116 if (DECL_SIZE (field) != NULL
1117 && host_integerp (TYPE_SIZE (TREE_TYPE (field)), 0)
1118 && host_integerp (DECL_SIZE (field), 0))
1119 rli->remaining_in_alignment
1120 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field)), 0)
1121 - tree_low_cst (DECL_SIZE (field), 0);
1123 /* Now align (conventionally) for the new type. */
1124 if (!DECL_PACKED(field))
1125 type_align = MAX(TYPE_ALIGN (type), type_align);
1128 && DECL_BIT_FIELD_TYPE (prev_saved)
1129 /* If the previous bit-field is zero-sized, we've already
1130 accounted for its alignment needs (or ignored it, if
1131 appropriate) while placing it. */
1132 && ! integer_zerop (DECL_SIZE (prev_saved)))
1133 type_align = MAX (type_align,
1134 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1136 if (maximum_field_alignment != 0)
1137 type_align = MIN (type_align, maximum_field_alignment);
1139 rli->bitpos = round_up (rli->bitpos, type_align);
1141 /* If we really aligned, don't allow subsequent bitfields
1143 rli->prev_field = NULL;
1147 /* Offset so far becomes the position of this field after normalizing. */
1148 normalize_rli (rli);
1149 DECL_FIELD_OFFSET (field) = rli->offset;
1150 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1151 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1153 /* If this field ended up more aligned than we thought it would be (we
1154 approximate this by seeing if its position changed), lay out the field
1155 again; perhaps we can use an integral mode for it now. */
1156 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1157 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1158 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1159 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1160 actual_align = BIGGEST_ALIGNMENT;
1161 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1162 actual_align = (BITS_PER_UNIT
1163 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1164 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1166 actual_align = DECL_OFFSET_ALIGN (field);
1168 if (known_align != actual_align)
1169 layout_decl (field, actual_align);
1171 /* Only the MS bitfields use this. */
1172 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1173 rli->prev_field = field;
1175 /* Now add size of this field to the size of the record. If the size is
1176 not constant, treat the field as being a multiple of bytes and just
1177 adjust the offset, resetting the bit position. Otherwise, apportion the
1178 size amongst the bit position and offset. First handle the case of an
1179 unspecified size, which can happen when we have an invalid nested struct
1180 definition, such as struct j { struct j { int i; } }. The error message
1181 is printed in finish_struct. */
1182 if (DECL_SIZE (field) == 0)
1184 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1185 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1188 = size_binop (PLUS_EXPR, rli->offset,
1190 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1191 bitsize_unit_node)));
1193 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1194 rli->bitpos = bitsize_zero_node;
1195 rli->offset_align = MIN (rli->offset_align, desired_align);
1199 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1200 normalize_rli (rli);
1204 /* Assuming that all the fields have been laid out, this function uses
1205 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1206 indicated by RLI. */
1209 finalize_record_size (record_layout_info rli)
1211 tree unpadded_size, unpadded_size_unit;
1213 /* Now we want just byte and bit offsets, so set the offset alignment
1214 to be a byte and then normalize. */
1215 rli->offset_align = BITS_PER_UNIT;
1216 normalize_rli (rli);
1218 /* Determine the desired alignment. */
1219 #ifdef ROUND_TYPE_ALIGN
1220 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1223 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1226 /* Compute the size so far. Be sure to allow for extra bits in the
1227 size in bytes. We have guaranteed above that it will be no more
1228 than a single byte. */
1229 unpadded_size = rli_size_so_far (rli);
1230 unpadded_size_unit = rli_size_unit_so_far (rli);
1231 if (! integer_zerop (rli->bitpos))
1233 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1235 /* Round the size up to be a multiple of the required alignment. */
1236 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1237 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1238 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1240 if (warn_padded && TREE_CONSTANT (unpadded_size)
1241 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1242 warning ("padding struct size to alignment boundary");
1244 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1245 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1246 && TREE_CONSTANT (unpadded_size))
1250 #ifdef ROUND_TYPE_ALIGN
1252 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1254 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1257 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1258 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1260 TYPE_PACKED (rli->t) = 0;
1262 if (TYPE_NAME (rli->t))
1266 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1267 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1269 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1271 if (STRICT_ALIGNMENT)
1272 warning ("packed attribute causes inefficient alignment for `%s'", name);
1274 warning ("packed attribute is unnecessary for `%s'", name);
1278 if (STRICT_ALIGNMENT)
1279 warning ("packed attribute causes inefficient alignment");
1281 warning ("packed attribute is unnecessary");
1287 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1290 compute_record_mode (tree type)
1293 enum machine_mode mode = VOIDmode;
1295 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1296 However, if possible, we use a mode that fits in a register
1297 instead, in order to allow for better optimization down the
1299 TYPE_MODE (type) = BLKmode;
1301 if (! host_integerp (TYPE_SIZE (type), 1))
1304 /* A record which has any BLKmode members must itself be
1305 BLKmode; it can't go in a register. Unless the member is
1306 BLKmode only because it isn't aligned. */
1307 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1309 if (TREE_CODE (field) != FIELD_DECL)
1312 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1313 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1314 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))
1315 && !(TYPE_SIZE (TREE_TYPE (field)) != 0
1316 && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))))
1317 || ! host_integerp (bit_position (field), 1)
1318 || DECL_SIZE (field) == 0
1319 || ! host_integerp (DECL_SIZE (field), 1))
1322 /* If this field is the whole struct, remember its mode so
1323 that, say, we can put a double in a class into a DF
1324 register instead of forcing it to live in the stack. */
1325 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1326 mode = DECL_MODE (field);
1328 #ifdef MEMBER_TYPE_FORCES_BLK
1329 /* With some targets, eg. c4x, it is sub-optimal
1330 to access an aligned BLKmode structure as a scalar. */
1332 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1334 #endif /* MEMBER_TYPE_FORCES_BLK */
1337 /* If we only have one real field; use its mode. This only applies to
1338 RECORD_TYPE. This does not apply to unions. */
1339 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1340 TYPE_MODE (type) = mode;
1342 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1344 /* If structure's known alignment is less than what the scalar
1345 mode would need, and it matters, then stick with BLKmode. */
1346 if (TYPE_MODE (type) != BLKmode
1348 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1349 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1351 /* If this is the only reason this type is BLKmode, then
1352 don't force containing types to be BLKmode. */
1353 TYPE_NO_FORCE_BLK (type) = 1;
1354 TYPE_MODE (type) = BLKmode;
1358 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1362 finalize_type_size (tree type)
1364 /* Normally, use the alignment corresponding to the mode chosen.
1365 However, where strict alignment is not required, avoid
1366 over-aligning structures, since most compilers do not do this
1369 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1370 && (STRICT_ALIGNMENT
1371 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1372 && TREE_CODE (type) != QUAL_UNION_TYPE
1373 && TREE_CODE (type) != ARRAY_TYPE)))
1375 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1376 TYPE_USER_ALIGN (type) = 0;
1379 /* Do machine-dependent extra alignment. */
1380 #ifdef ROUND_TYPE_ALIGN
1382 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1385 /* If we failed to find a simple way to calculate the unit size
1386 of the type, find it by division. */
1387 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1388 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1389 result will fit in sizetype. We will get more efficient code using
1390 sizetype, so we force a conversion. */
1391 TYPE_SIZE_UNIT (type)
1392 = convert (sizetype,
1393 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1394 bitsize_unit_node));
1396 if (TYPE_SIZE (type) != 0)
1398 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1399 TYPE_SIZE_UNIT (type)
1400 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1403 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1404 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1405 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1406 if (TYPE_SIZE_UNIT (type) != 0
1407 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1408 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1410 /* Also layout any other variants of the type. */
1411 if (TYPE_NEXT_VARIANT (type)
1412 || type != TYPE_MAIN_VARIANT (type))
1415 /* Record layout info of this variant. */
1416 tree size = TYPE_SIZE (type);
1417 tree size_unit = TYPE_SIZE_UNIT (type);
1418 unsigned int align = TYPE_ALIGN (type);
1419 unsigned int user_align = TYPE_USER_ALIGN (type);
1420 enum machine_mode mode = TYPE_MODE (type);
1422 /* Copy it into all variants. */
1423 for (variant = TYPE_MAIN_VARIANT (type);
1425 variant = TYPE_NEXT_VARIANT (variant))
1427 TYPE_SIZE (variant) = size;
1428 TYPE_SIZE_UNIT (variant) = size_unit;
1429 TYPE_ALIGN (variant) = align;
1430 TYPE_USER_ALIGN (variant) = user_align;
1431 TYPE_MODE (variant) = mode;
1436 /* Do all of the work required to layout the type indicated by RLI,
1437 once the fields have been laid out. This function will call `free'
1438 for RLI, unless FREE_P is false. Passing a value other than false
1439 for FREE_P is bad practice; this option only exists to support the
1443 finish_record_layout (record_layout_info rli, int free_p)
1445 /* Compute the final size. */
1446 finalize_record_size (rli);
1448 /* Compute the TYPE_MODE for the record. */
1449 compute_record_mode (rli->t);
1451 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1452 finalize_type_size (rli->t);
1454 /* Lay out any static members. This is done now because their type
1455 may use the record's type. */
1456 while (rli->pending_statics)
1458 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1459 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1468 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1469 NAME, its fields are chained in reverse on FIELDS.
1471 If ALIGN_TYPE is non-null, it is given the same alignment as
1475 finish_builtin_struct (tree type, const char *name, tree fields,
1480 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1482 DECL_FIELD_CONTEXT (fields) = type;
1483 next = TREE_CHAIN (fields);
1484 TREE_CHAIN (fields) = tail;
1486 TYPE_FIELDS (type) = tail;
1490 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1491 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1495 #if 0 /* not yet, should get fixed properly later */
1496 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1498 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1500 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1501 layout_decl (TYPE_NAME (type), 0);
1504 /* Calculate the mode, size, and alignment for TYPE.
1505 For an array type, calculate the element separation as well.
1506 Record TYPE on the chain of permanent or temporary types
1507 so that dbxout will find out about it.
1509 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1510 layout_type does nothing on such a type.
1512 If the type is incomplete, its TYPE_SIZE remains zero. */
1515 layout_type (tree type)
1520 /* Do nothing if type has been laid out before. */
1521 if (TYPE_SIZE (type))
1524 switch (TREE_CODE (type))
1527 /* This kind of type is the responsibility
1528 of the language-specific code. */
1531 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1532 if (TYPE_PRECISION (type) == 0)
1533 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1535 /* ... fall through ... */
1540 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1541 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1542 TREE_UNSIGNED (type) = 1;
1544 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1546 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1547 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1551 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1552 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1553 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1557 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1559 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1560 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1561 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
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)));
1571 subtype = TREE_TYPE (type);
1572 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1573 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1574 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1579 /* This is an incomplete type and so doesn't have a size. */
1580 TYPE_ALIGN (type) = 1;
1581 TYPE_USER_ALIGN (type) = 0;
1582 TYPE_MODE (type) = VOIDmode;
1586 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1587 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1588 /* A pointer might be MODE_PARTIAL_INT,
1589 but ptrdiff_t must be integral. */
1590 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1595 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1596 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1597 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1601 case REFERENCE_TYPE:
1604 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1605 && reference_types_internal)
1606 ? Pmode : TYPE_MODE (type));
1608 int nbits = GET_MODE_BITSIZE (mode);
1610 TYPE_SIZE (type) = bitsize_int (nbits);
1611 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1612 TREE_UNSIGNED (type) = 1;
1613 TYPE_PRECISION (type) = nbits;
1619 tree index = TYPE_DOMAIN (type);
1620 tree element = TREE_TYPE (type);
1622 build_pointer_type (element);
1624 /* We need to know both bounds in order to compute the size. */
1625 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1626 && TYPE_SIZE (element))
1628 tree ub = TYPE_MAX_VALUE (index);
1629 tree lb = TYPE_MIN_VALUE (index);
1633 /* The initial subtraction should happen in the original type so
1634 that (possible) negative values are handled appropriately. */
1635 length = size_binop (PLUS_EXPR, size_one_node,
1637 fold (build (MINUS_EXPR,
1641 /* Special handling for arrays of bits (for Chill). */
1642 element_size = TYPE_SIZE (element);
1643 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1644 && (integer_zerop (TYPE_MAX_VALUE (element))
1645 || integer_onep (TYPE_MAX_VALUE (element)))
1646 && host_integerp (TYPE_MIN_VALUE (element), 1))
1648 HOST_WIDE_INT maxvalue
1649 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1650 HOST_WIDE_INT minvalue
1651 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1653 if (maxvalue - minvalue == 1
1654 && (maxvalue == 1 || maxvalue == 0))
1655 element_size = integer_one_node;
1658 /* If neither bound is a constant and sizetype is signed, make
1659 sure the size is never negative. We should really do this
1660 if *either* bound is non-constant, but this is the best
1661 compromise between C and Ada. */
1662 if (! TREE_UNSIGNED (sizetype)
1663 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
1664 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
1665 length = size_binop (MAX_EXPR, length, size_zero_node);
1667 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1668 convert (bitsizetype, length));
1670 /* If we know the size of the element, calculate the total
1671 size directly, rather than do some division thing below.
1672 This optimization helps Fortran assumed-size arrays
1673 (where the size of the array is determined at runtime)
1675 Note that we can't do this in the case where the size of
1676 the elements is one bit since TYPE_SIZE_UNIT cannot be
1677 set correctly in that case. */
1678 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1679 TYPE_SIZE_UNIT (type)
1680 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1683 /* Now round the alignment and size,
1684 using machine-dependent criteria if any. */
1686 #ifdef ROUND_TYPE_ALIGN
1688 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1690 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1692 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1693 TYPE_MODE (type) = BLKmode;
1694 if (TYPE_SIZE (type) != 0
1695 #ifdef MEMBER_TYPE_FORCES_BLK
1696 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1698 /* BLKmode elements force BLKmode aggregate;
1699 else extract/store fields may lose. */
1700 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1701 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1703 /* One-element arrays get the component type's mode. */
1704 if (simple_cst_equal (TYPE_SIZE (type),
1705 TYPE_SIZE (TREE_TYPE (type))))
1706 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1709 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1711 if (TYPE_MODE (type) != BLKmode
1712 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1713 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1714 && TYPE_MODE (type) != BLKmode)
1716 TYPE_NO_FORCE_BLK (type) = 1;
1717 TYPE_MODE (type) = BLKmode;
1725 case QUAL_UNION_TYPE:
1728 record_layout_info rli;
1730 /* Initialize the layout information. */
1731 rli = start_record_layout (type);
1733 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1734 in the reverse order in building the COND_EXPR that denotes
1735 its size. We reverse them again later. */
1736 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1737 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1739 /* Place all the fields. */
1740 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1741 place_field (rli, field);
1743 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1744 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1746 if (lang_adjust_rli)
1747 (*lang_adjust_rli) (rli);
1749 /* Finish laying out the record. */
1750 finish_record_layout (rli, /*free_p=*/true);
1754 case SET_TYPE: /* Used by Chill and Pascal. */
1755 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1756 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1760 #ifndef SET_WORD_SIZE
1761 #define SET_WORD_SIZE BITS_PER_WORD
1763 unsigned int alignment
1764 = set_alignment ? set_alignment : SET_WORD_SIZE;
1765 HOST_WIDE_INT size_in_bits
1766 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), 0)
1767 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0) + 1);
1768 HOST_WIDE_INT rounded_size
1769 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1771 if (rounded_size > (int) alignment)
1772 TYPE_MODE (type) = BLKmode;
1774 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1776 TYPE_SIZE (type) = bitsize_int (rounded_size);
1777 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1778 TYPE_ALIGN (type) = alignment;
1779 TYPE_USER_ALIGN (type) = 0;
1780 TYPE_PRECISION (type) = size_in_bits;
1785 /* The size may vary in different languages, so the language front end
1786 should fill in the size. */
1787 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1788 TYPE_USER_ALIGN (type) = 0;
1789 TYPE_MODE (type) = BLKmode;
1796 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1797 records and unions, finish_record_layout already called this
1799 if (TREE_CODE (type) != RECORD_TYPE
1800 && TREE_CODE (type) != UNION_TYPE
1801 && TREE_CODE (type) != QUAL_UNION_TYPE)
1802 finalize_type_size (type);
1804 /* If this type is created before sizetype has been permanently set,
1805 record it so set_sizetype can fix it up. */
1807 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1809 /* If an alias set has been set for this aggregate when it was incomplete,
1810 force it into alias set 0.
1811 This is too conservative, but we cannot call record_component_aliases
1812 here because some frontends still change the aggregates after
1814 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1815 TYPE_ALIAS_SET (type) = 0;
1818 /* Create and return a type for signed integers of PRECISION bits. */
1821 make_signed_type (int precision)
1823 tree type = make_node (INTEGER_TYPE);
1825 TYPE_PRECISION (type) = precision;
1827 fixup_signed_type (type);
1831 /* Create and return a type for unsigned integers of PRECISION bits. */
1834 make_unsigned_type (int precision)
1836 tree type = make_node (INTEGER_TYPE);
1838 TYPE_PRECISION (type) = precision;
1840 fixup_unsigned_type (type);
1844 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1845 value to enable integer types to be created. */
1848 initialize_sizetypes (void)
1850 tree t = make_node (INTEGER_TYPE);
1852 /* Set this so we do something reasonable for the build_int_2 calls
1854 integer_type_node = t;
1856 TYPE_MODE (t) = SImode;
1857 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1858 TYPE_USER_ALIGN (t) = 0;
1859 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1860 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1861 TREE_UNSIGNED (t) = 1;
1862 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1863 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1864 TYPE_IS_SIZETYPE (t) = 1;
1866 /* 1000 avoids problems with possible overflow and is certainly
1867 larger than any size value we'd want to be storing. */
1868 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1870 /* These two must be different nodes because of the caching done in
1873 bitsizetype = copy_node (t);
1874 integer_type_node = 0;
1877 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1878 Also update the type of any standard type's sizes made so far. */
1881 set_sizetype (tree type)
1883 int oprecision = TYPE_PRECISION (type);
1884 /* The *bitsizetype types use a precision that avoids overflows when
1885 calculating signed sizes / offsets in bits. However, when
1886 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1888 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1889 2 * HOST_BITS_PER_WIDE_INT);
1896 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1897 sizetype = copy_node (type);
1898 TYPE_DOMAIN (sizetype) = type;
1899 TYPE_IS_SIZETYPE (sizetype) = 1;
1900 bitsizetype = make_node (INTEGER_TYPE);
1901 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1902 TYPE_PRECISION (bitsizetype) = precision;
1903 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1905 if (TREE_UNSIGNED (type))
1906 fixup_unsigned_type (bitsizetype);
1908 fixup_signed_type (bitsizetype);
1910 layout_type (bitsizetype);
1912 if (TREE_UNSIGNED (type))
1914 usizetype = sizetype;
1915 ubitsizetype = bitsizetype;
1916 ssizetype = copy_node (make_signed_type (oprecision));
1917 sbitsizetype = copy_node (make_signed_type (precision));
1921 ssizetype = sizetype;
1922 sbitsizetype = bitsizetype;
1923 usizetype = copy_node (make_unsigned_type (oprecision));
1924 ubitsizetype = copy_node (make_unsigned_type (precision));
1927 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1929 /* Show is a sizetype, is a main type, and has no pointers to it. */
1930 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1932 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1933 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1934 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1935 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1936 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1939 /* Go down each of the types we already made and set the proper type
1940 for the sizes in them. */
1941 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1943 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE
1944 && TREE_CODE (TREE_VALUE (t)) != BOOLEAN_TYPE)
1947 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1948 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1951 early_type_list = 0;
1955 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1956 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1957 for TYPE, based on the PRECISION and whether or not the TYPE
1958 IS_UNSIGNED. PRECISION need not correspond to a width supported
1959 natively by the hardware; for example, on a machine with 8-bit,
1960 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1964 set_min_and_max_values_for_integral_type (tree type,
1973 min_value = build_int_2 (0, 0);
1975 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1976 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1977 precision - HOST_BITS_PER_WIDE_INT > 0
1978 ? ((unsigned HOST_WIDE_INT) ~0
1979 >> (HOST_BITS_PER_WIDE_INT
1980 - (precision - HOST_BITS_PER_WIDE_INT)))
1986 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1987 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1988 (((HOST_WIDE_INT) (-1)
1989 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1990 ? precision - HOST_BITS_PER_WIDE_INT - 1
1993 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1994 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1995 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1996 ? (((HOST_WIDE_INT) 1
1997 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2001 TREE_TYPE (min_value) = type;
2002 TREE_TYPE (max_value) = type;
2003 TYPE_MIN_VALUE (type) = min_value;
2004 TYPE_MAX_VALUE (type) = max_value;
2007 /* Set the extreme values of TYPE based on its precision in bits,
2008 then lay it out. Used when make_signed_type won't do
2009 because the tree code is not INTEGER_TYPE.
2010 E.g. for Pascal, when the -fsigned-char option is given. */
2013 fixup_signed_type (tree type)
2015 int precision = TYPE_PRECISION (type);
2017 /* We can not represent properly constants greater then
2018 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2019 as they are used by i386 vector extensions and friends. */
2020 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2021 precision = HOST_BITS_PER_WIDE_INT * 2;
2023 set_min_and_max_values_for_integral_type (type, precision,
2024 /*is_unsigned=*/false);
2026 /* Lay out the type: set its alignment, size, etc. */
2030 /* Set the extreme values of TYPE based on its precision in bits,
2031 then lay it out. This is used both in `make_unsigned_type'
2032 and for enumeral types. */
2035 fixup_unsigned_type (tree type)
2037 int precision = TYPE_PRECISION (type);
2039 /* We can not represent properly constants greater then
2040 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2041 as they are used by i386 vector extensions and friends. */
2042 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2043 precision = HOST_BITS_PER_WIDE_INT * 2;
2045 set_min_and_max_values_for_integral_type (type, precision,
2046 /*is_unsigned=*/true);
2048 /* Lay out the type: set its alignment, size, etc. */
2052 /* Find the best machine mode to use when referencing a bit field of length
2053 BITSIZE bits starting at BITPOS.
2055 The underlying object is known to be aligned to a boundary of ALIGN bits.
2056 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2057 larger than LARGEST_MODE (usually SImode).
2059 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2060 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2061 mode meeting these conditions.
2063 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2064 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2065 all the conditions. */
2068 get_best_mode (int bitsize, int bitpos, unsigned int align,
2069 enum machine_mode largest_mode, int volatilep)
2071 enum machine_mode mode;
2072 unsigned int unit = 0;
2074 /* Find the narrowest integer mode that contains the bit field. */
2075 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2076 mode = GET_MODE_WIDER_MODE (mode))
2078 unit = GET_MODE_BITSIZE (mode);
2079 if ((bitpos % unit) + bitsize <= unit)
2083 if (mode == VOIDmode
2084 /* It is tempting to omit the following line
2085 if STRICT_ALIGNMENT is true.
2086 But that is incorrect, since if the bitfield uses part of 3 bytes
2087 and we use a 4-byte mode, we could get a spurious segv
2088 if the extra 4th byte is past the end of memory.
2089 (Though at least one Unix compiler ignores this problem:
2090 that on the Sequent 386 machine. */
2091 || MIN (unit, BIGGEST_ALIGNMENT) > align
2092 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2095 if (SLOW_BYTE_ACCESS && ! volatilep)
2097 enum machine_mode wide_mode = VOIDmode, tmode;
2099 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2100 tmode = GET_MODE_WIDER_MODE (tmode))
2102 unit = GET_MODE_BITSIZE (tmode);
2103 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2104 && unit <= BITS_PER_WORD
2105 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2106 && (largest_mode == VOIDmode
2107 || unit <= GET_MODE_BITSIZE (largest_mode)))
2111 if (wide_mode != VOIDmode)
2118 #include "gt-stor-layout.h"