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 unsigned int alignment;
303 if (GET_MODE_CLASS (mode) == MODE_COMPLEX_FLOAT
304 || GET_MODE_CLASS (mode) == MODE_COMPLEX_INT)
305 alignment = GET_MODE_UNIT_SIZE (mode);
307 alignment = GET_MODE_SIZE (mode);
309 /* Extract the LSB of the size. */
310 alignment = alignment & -alignment;
311 alignment *= BITS_PER_UNIT;
313 alignment = MIN (BIGGEST_ALIGNMENT, MAX (1, alignment));
317 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
318 This can only be applied to objects of a sizetype. */
321 round_up (tree value, int divisor)
323 tree arg = size_int_type (divisor, TREE_TYPE (value));
325 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
328 /* Likewise, but round down. */
331 round_down (tree value, int divisor)
333 tree arg = size_int_type (divisor, TREE_TYPE (value));
335 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
338 /* Subroutine of layout_decl: Force alignment required for the data type.
339 But if the decl itself wants greater alignment, don't override that. */
342 do_type_align (tree type, tree decl)
344 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
346 DECL_ALIGN (decl) = TYPE_ALIGN (type);
347 if (TREE_CODE (decl) == FIELD_DECL)
348 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
352 /* Set the size, mode and alignment of a ..._DECL node.
353 TYPE_DECL does need this for C++.
354 Note that LABEL_DECL and CONST_DECL nodes do not need this,
355 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
356 Don't call layout_decl for them.
358 KNOWN_ALIGN is the amount of alignment we can assume this
359 decl has with no special effort. It is relevant only for FIELD_DECLs
360 and depends on the previous fields.
361 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
362 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
363 the record will be aligned to suit. */
366 layout_decl (tree decl, unsigned int known_align)
368 tree type = TREE_TYPE (decl);
369 enum tree_code code = TREE_CODE (decl);
372 if (code == CONST_DECL)
374 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
375 && code != TYPE_DECL && code != FIELD_DECL)
378 rtl = DECL_RTL_IF_SET (decl);
380 if (type == error_mark_node)
381 type = void_type_node;
383 /* Usually the size and mode come from the data type without change,
384 however, the front-end may set the explicit width of the field, so its
385 size may not be the same as the size of its type. This happens with
386 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
387 also happens with other fields. For example, the C++ front-end creates
388 zero-sized fields corresponding to empty base classes, and depends on
389 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
390 size in bytes from the size in bits. If we have already set the mode,
391 don't set it again since we can be called twice for FIELD_DECLs. */
393 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
394 if (DECL_MODE (decl) == VOIDmode)
395 DECL_MODE (decl) = TYPE_MODE (type);
397 if (DECL_SIZE (decl) == 0)
399 DECL_SIZE (decl) = TYPE_SIZE (type);
400 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
402 else if (DECL_SIZE_UNIT (decl) == 0)
403 DECL_SIZE_UNIT (decl)
404 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
407 if (code != FIELD_DECL)
408 /* For non-fields, update the alignment from the type. */
409 do_type_align (type, decl);
411 /* For fields, it's a bit more complicated... */
413 if (DECL_BIT_FIELD (decl))
415 DECL_BIT_FIELD_TYPE (decl) = type;
417 /* A zero-length bit-field affects the alignment of the next
419 if (integer_zerop (DECL_SIZE (decl))
420 && ! DECL_PACKED (decl)
421 && ! (*targetm.ms_bitfield_layout_p) (DECL_FIELD_CONTEXT (decl)))
423 #ifdef PCC_BITFIELD_TYPE_MATTERS
424 if (PCC_BITFIELD_TYPE_MATTERS)
425 do_type_align (type, decl);
429 #ifdef EMPTY_FIELD_BOUNDARY
430 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
432 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
433 DECL_USER_ALIGN (decl) = 0;
439 /* See if we can use an ordinary integer mode for a bit-field.
440 Conditions are: a fixed size that is correct for another mode
441 and occupying a complete byte or bytes on proper boundary. */
442 if (TYPE_SIZE (type) != 0
443 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
444 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
446 enum machine_mode xmode
447 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
449 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
451 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
453 DECL_MODE (decl) = xmode;
454 DECL_BIT_FIELD (decl) = 0;
458 /* Turn off DECL_BIT_FIELD if we won't need it set. */
459 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
460 && known_align >= TYPE_ALIGN (type)
461 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
462 DECL_BIT_FIELD (decl) = 0;
464 else if (DECL_PACKED (decl) && DECL_USER_ALIGN (decl))
465 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
466 round up; we'll reduce it again below. */;
468 do_type_align (type, decl);
470 /* If the field is of variable size, we can't misalign it since we
471 have no way to make a temporary to align the result. But this
472 isn't an issue if the decl is not addressable. Likewise if it
473 is of unknown size. */
474 if (DECL_PACKED (decl)
475 && !DECL_USER_ALIGN (decl)
476 && (DECL_NONADDRESSABLE_P (decl)
477 || DECL_SIZE_UNIT (decl) == 0
478 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
479 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
481 /* Should this be controlled by DECL_USER_ALIGN, too? */
482 if (maximum_field_alignment != 0)
483 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
484 if (! DECL_USER_ALIGN (decl))
486 /* Some targets (i.e. i386, VMS) limit struct field alignment
487 to a lower boundary than alignment of variables unless
488 it was overridden by attribute aligned. */
489 #ifdef BIGGEST_FIELD_ALIGNMENT
491 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
493 #ifdef ADJUST_FIELD_ALIGN
494 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
499 /* Evaluate nonconstant size only once, either now or as soon as safe. */
500 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
501 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
502 if (DECL_SIZE_UNIT (decl) != 0
503 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
504 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
506 /* If requested, warn about definitions of large data objects. */
508 && (code == VAR_DECL || code == PARM_DECL)
509 && ! DECL_EXTERNAL (decl))
511 tree size = DECL_SIZE_UNIT (decl);
513 if (size != 0 && TREE_CODE (size) == INTEGER_CST
514 && compare_tree_int (size, larger_than_size) > 0)
516 int size_as_int = TREE_INT_CST_LOW (size);
518 if (compare_tree_int (size, size_as_int) == 0)
519 warning ("%Jsize of '%D' is %d bytes", decl, decl, size_as_int);
521 warning ("%Jsize of '%D' is larger than %d bytes",
522 decl, decl, larger_than_size);
526 /* If the RTL was already set, update its mode and mem attributes. */
529 PUT_MODE (rtl, DECL_MODE (decl));
530 SET_DECL_RTL (decl, 0);
531 set_mem_attributes (rtl, decl, 1);
532 SET_DECL_RTL (decl, rtl);
536 /* Hook for a front-end function that can modify the record layout as needed
537 immediately before it is finalized. */
539 void (*lang_adjust_rli) (record_layout_info) = 0;
542 set_lang_adjust_rli (void (*f) (record_layout_info))
547 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
548 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
549 is to be passed to all other layout functions for this record. It is the
550 responsibility of the caller to call `free' for the storage returned.
551 Note that garbage collection is not permitted until we finish laying
555 start_record_layout (tree t)
557 record_layout_info rli = xmalloc (sizeof (struct record_layout_info_s));
561 /* If the type has a minimum specified alignment (via an attribute
562 declaration, for example) use it -- otherwise, start with a
563 one-byte alignment. */
564 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
565 rli->unpacked_align = rli->record_align;
566 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
568 #ifdef STRUCTURE_SIZE_BOUNDARY
569 /* Packed structures don't need to have minimum size. */
570 if (! TYPE_PACKED (t))
571 rli->record_align = MAX (rli->record_align, (unsigned) STRUCTURE_SIZE_BOUNDARY);
574 rli->offset = size_zero_node;
575 rli->bitpos = bitsize_zero_node;
577 rli->pending_statics = 0;
578 rli->packed_maybe_necessary = 0;
583 /* These four routines perform computations that convert between
584 the offset/bitpos forms and byte and bit offsets. */
587 bit_from_pos (tree offset, tree bitpos)
589 return size_binop (PLUS_EXPR, bitpos,
590 size_binop (MULT_EXPR, convert (bitsizetype, offset),
595 byte_from_pos (tree offset, tree bitpos)
597 return size_binop (PLUS_EXPR, offset,
599 size_binop (TRUNC_DIV_EXPR, bitpos,
600 bitsize_unit_node)));
604 pos_from_bit (tree *poffset, tree *pbitpos, unsigned int off_align,
607 *poffset = size_binop (MULT_EXPR,
609 size_binop (FLOOR_DIV_EXPR, pos,
610 bitsize_int (off_align))),
611 size_int (off_align / BITS_PER_UNIT));
612 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
615 /* Given a pointer to bit and byte offsets and an offset alignment,
616 normalize the offsets so they are within the alignment. */
619 normalize_offset (tree *poffset, tree *pbitpos, unsigned int off_align)
621 /* If the bit position is now larger than it should be, adjust it
623 if (compare_tree_int (*pbitpos, off_align) >= 0)
625 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
626 bitsize_int (off_align));
629 = size_binop (PLUS_EXPR, *poffset,
630 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
631 size_int (off_align / BITS_PER_UNIT)));
634 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
638 /* Print debugging information about the information in RLI. */
641 debug_rli (record_layout_info rli)
643 print_node_brief (stderr, "type", rli->t, 0);
644 print_node_brief (stderr, "\noffset", rli->offset, 0);
645 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
647 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
648 rli->record_align, rli->unpacked_align,
650 if (rli->packed_maybe_necessary)
651 fprintf (stderr, "packed may be necessary\n");
653 if (rli->pending_statics)
655 fprintf (stderr, "pending statics:\n");
656 debug_tree (rli->pending_statics);
660 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
661 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
664 normalize_rli (record_layout_info rli)
666 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
669 /* Returns the size in bytes allocated so far. */
672 rli_size_unit_so_far (record_layout_info rli)
674 return byte_from_pos (rli->offset, rli->bitpos);
677 /* Returns the size in bits allocated so far. */
680 rli_size_so_far (record_layout_info rli)
682 return bit_from_pos (rli->offset, rli->bitpos);
685 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
686 the next available location is given by KNOWN_ALIGN. Update the
687 variable alignment fields in RLI, and return the alignment to give
691 update_alignment_for_field (record_layout_info rli, tree field,
692 unsigned int known_align)
694 /* The alignment required for FIELD. */
695 unsigned int desired_align;
696 /* The type of this field. */
697 tree type = TREE_TYPE (field);
698 /* True if the field was explicitly aligned by the user. */
702 /* Lay out the field so we know what alignment it needs. */
703 layout_decl (field, known_align);
704 desired_align = DECL_ALIGN (field);
705 user_align = DECL_USER_ALIGN (field);
707 is_bitfield = (type != error_mark_node
708 && DECL_BIT_FIELD_TYPE (field)
709 && ! integer_zerop (TYPE_SIZE (type)));
711 /* Record must have at least as much alignment as any field.
712 Otherwise, the alignment of the field within the record is
714 if (is_bitfield && (* targetm.ms_bitfield_layout_p) (rli->t))
716 /* Here, the alignment of the underlying type of a bitfield can
717 affect the alignment of a record; even a zero-sized field
718 can do this. The alignment should be to the alignment of
719 the type, except that for zero-size bitfields this only
720 applies if there was an immediately prior, nonzero-size
721 bitfield. (That's the way it is, experimentally.) */
722 if (! integer_zerop (DECL_SIZE (field))
723 ? ! DECL_PACKED (field)
725 && DECL_BIT_FIELD_TYPE (rli->prev_field)
726 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
728 unsigned int type_align = TYPE_ALIGN (type);
729 type_align = MAX (type_align, desired_align);
730 if (maximum_field_alignment != 0)
731 type_align = MIN (type_align, maximum_field_alignment);
732 rli->record_align = MAX (rli->record_align, type_align);
733 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
736 #ifdef PCC_BITFIELD_TYPE_MATTERS
737 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
739 /* Named bit-fields cause the entire structure to have the
740 alignment implied by their type. */
741 if (DECL_NAME (field) != 0)
743 unsigned int type_align = TYPE_ALIGN (type);
745 #ifdef ADJUST_FIELD_ALIGN
746 if (! TYPE_USER_ALIGN (type))
747 type_align = ADJUST_FIELD_ALIGN (field, type_align);
750 if (maximum_field_alignment != 0)
751 type_align = MIN (type_align, maximum_field_alignment);
752 else if (DECL_PACKED (field))
753 type_align = MIN (type_align, BITS_PER_UNIT);
755 /* The alignment of the record is increased to the maximum
756 of the current alignment, the alignment indicated on the
757 field (i.e., the alignment specified by an __aligned__
758 attribute), and the alignment indicated by the type of
760 rli->record_align = MAX (rli->record_align, desired_align);
761 rli->record_align = MAX (rli->record_align, type_align);
764 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
765 user_align |= TYPE_USER_ALIGN (type);
771 rli->record_align = MAX (rli->record_align, desired_align);
772 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
775 TYPE_USER_ALIGN (rli->t) |= user_align;
777 return desired_align;
780 /* Called from place_field to handle unions. */
783 place_union_field (record_layout_info rli, tree field)
785 update_alignment_for_field (rli, field, /*known_align=*/0);
787 DECL_FIELD_OFFSET (field) = size_zero_node;
788 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
789 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
791 /* We assume the union's size will be a multiple of a byte so we don't
792 bother with BITPOS. */
793 if (TREE_CODE (rli->t) == UNION_TYPE)
794 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
795 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
796 rli->offset = fold (build (COND_EXPR, sizetype,
797 DECL_QUALIFIER (field),
798 DECL_SIZE_UNIT (field), rli->offset));
801 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
802 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
803 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
804 units of alignment than the underlying TYPE. */
806 excess_unit_span (HOST_WIDE_INT byte_offset, HOST_WIDE_INT bit_offset,
807 HOST_WIDE_INT size, HOST_WIDE_INT align, tree type)
809 /* Note that the calculation of OFFSET might overflow; we calculate it so
810 that we still get the right result as long as ALIGN is a power of two. */
811 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
813 offset = offset % align;
814 return ((offset + size + align - 1) / align
815 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
820 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
821 is a FIELD_DECL to be added after those fields already present in
822 T. (FIELD is not actually added to the TYPE_FIELDS list here;
823 callers that desire that behavior must manually perform that step.) */
826 place_field (record_layout_info rli, tree field)
828 /* The alignment required for FIELD. */
829 unsigned int desired_align;
830 /* The alignment FIELD would have if we just dropped it into the
831 record as it presently stands. */
832 unsigned int known_align;
833 unsigned int actual_align;
834 /* The type of this field. */
835 tree type = TREE_TYPE (field);
837 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
840 /* If FIELD is static, then treat it like a separate variable, not
841 really like a structure field. If it is a FUNCTION_DECL, it's a
842 method. In both cases, all we do is lay out the decl, and we do
843 it *after* the record is laid out. */
844 if (TREE_CODE (field) == VAR_DECL)
846 rli->pending_statics = tree_cons (NULL_TREE, field,
847 rli->pending_statics);
851 /* Enumerators and enum types which are local to this class need not
852 be laid out. Likewise for initialized constant fields. */
853 else if (TREE_CODE (field) != FIELD_DECL)
856 /* Unions are laid out very differently than records, so split
857 that code off to another function. */
858 else if (TREE_CODE (rli->t) != RECORD_TYPE)
860 place_union_field (rli, field);
864 /* Work out the known alignment so far. Note that A & (-A) is the
865 value of the least-significant bit in A that is one. */
866 if (! integer_zerop (rli->bitpos))
867 known_align = (tree_low_cst (rli->bitpos, 1)
868 & - tree_low_cst (rli->bitpos, 1));
869 else if (integer_zerop (rli->offset))
870 known_align = BIGGEST_ALIGNMENT;
871 else if (host_integerp (rli->offset, 1))
872 known_align = (BITS_PER_UNIT
873 * (tree_low_cst (rli->offset, 1)
874 & - tree_low_cst (rli->offset, 1)));
876 known_align = rli->offset_align;
878 desired_align = update_alignment_for_field (rli, field, known_align);
880 if (warn_packed && DECL_PACKED (field))
882 if (known_align >= TYPE_ALIGN (type))
884 if (TYPE_ALIGN (type) > desired_align)
886 if (STRICT_ALIGNMENT)
887 warning ("%Jpacked attribute causes inefficient alignment "
888 "for '%D'", field, field);
890 warning ("%Jpacked attribute is unnecessary for '%D'",
895 rli->packed_maybe_necessary = 1;
898 /* Does this field automatically have alignment it needs by virtue
899 of the fields that precede it and the record's own alignment? */
900 if (known_align < desired_align)
902 /* No, we need to skip space before this field.
903 Bump the cumulative size to multiple of field alignment. */
906 warning ("%Jpadding struct to align '%D'", field, field);
908 /* If the alignment is still within offset_align, just align
910 if (desired_align < rli->offset_align)
911 rli->bitpos = round_up (rli->bitpos, desired_align);
914 /* First adjust OFFSET by the partial bits, then align. */
916 = size_binop (PLUS_EXPR, rli->offset,
918 size_binop (CEIL_DIV_EXPR, rli->bitpos,
919 bitsize_unit_node)));
920 rli->bitpos = bitsize_zero_node;
922 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
925 if (! TREE_CONSTANT (rli->offset))
926 rli->offset_align = desired_align;
930 /* Handle compatibility with PCC. Note that if the record has any
931 variable-sized fields, we need not worry about compatibility. */
932 #ifdef PCC_BITFIELD_TYPE_MATTERS
933 if (PCC_BITFIELD_TYPE_MATTERS
934 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
935 && TREE_CODE (field) == FIELD_DECL
936 && type != error_mark_node
937 && DECL_BIT_FIELD (field)
938 && ! DECL_PACKED (field)
939 && maximum_field_alignment == 0
940 && ! integer_zerop (DECL_SIZE (field))
941 && host_integerp (DECL_SIZE (field), 1)
942 && host_integerp (rli->offset, 1)
943 && host_integerp (TYPE_SIZE (type), 1))
945 unsigned int type_align = TYPE_ALIGN (type);
946 tree dsize = DECL_SIZE (field);
947 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
948 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
949 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
951 #ifdef ADJUST_FIELD_ALIGN
952 if (! TYPE_USER_ALIGN (type))
953 type_align = ADJUST_FIELD_ALIGN (field, type_align);
956 /* A bit field may not span more units of alignment of its type
957 than its type itself. Advance to next boundary if necessary. */
958 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
959 rli->bitpos = round_up (rli->bitpos, type_align);
961 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
965 #ifdef BITFIELD_NBYTES_LIMITED
966 if (BITFIELD_NBYTES_LIMITED
967 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
968 && TREE_CODE (field) == FIELD_DECL
969 && type != error_mark_node
970 && DECL_BIT_FIELD_TYPE (field)
971 && ! DECL_PACKED (field)
972 && ! integer_zerop (DECL_SIZE (field))
973 && host_integerp (DECL_SIZE (field), 1)
974 && host_integerp (rli->offset, 1)
975 && host_integerp (TYPE_SIZE (type), 1))
977 unsigned int type_align = TYPE_ALIGN (type);
978 tree dsize = DECL_SIZE (field);
979 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
980 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
981 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
983 #ifdef ADJUST_FIELD_ALIGN
984 if (! TYPE_USER_ALIGN (type))
985 type_align = ADJUST_FIELD_ALIGN (field, type_align);
988 if (maximum_field_alignment != 0)
989 type_align = MIN (type_align, maximum_field_alignment);
990 /* ??? This test is opposite the test in the containing if
991 statement, so this code is unreachable currently. */
992 else if (DECL_PACKED (field))
993 type_align = MIN (type_align, BITS_PER_UNIT);
995 /* A bit field may not span the unit of alignment of its type.
996 Advance to next boundary if necessary. */
997 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
998 rli->bitpos = round_up (rli->bitpos, type_align);
1000 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
1004 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1006 When a bit field is inserted into a packed record, the whole
1007 size of the underlying type is used by one or more same-size
1008 adjacent bitfields. (That is, if its long:3, 32 bits is
1009 used in the record, and any additional adjacent long bitfields are
1010 packed into the same chunk of 32 bits. However, if the size
1011 changes, a new field of that size is allocated.) In an unpacked
1012 record, this is the same as using alignment, but not equivalent
1015 Note: for compatibility, we use the type size, not the type alignment
1016 to determine alignment, since that matches the documentation */
1018 if ((* targetm.ms_bitfield_layout_p) (rli->t)
1019 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1020 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1022 /* At this point, either the prior or current are bitfields,
1023 (possibly both), and we're dealing with MS packing. */
1024 tree prev_saved = rli->prev_field;
1026 /* Is the prior field a bitfield? If so, handle "runs" of same
1027 type size fields. */
1028 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1030 /* If both are bitfields, nonzero, and the same size, this is
1031 the middle of a run. Zero declared size fields are special
1032 and handled as "end of run". (Note: it's nonzero declared
1033 size, but equal type sizes!) (Since we know that both
1034 the current and previous fields are bitfields by the
1035 time we check it, DECL_SIZE must be present for both.) */
1036 if (DECL_BIT_FIELD_TYPE (field)
1037 && !integer_zerop (DECL_SIZE (field))
1038 && !integer_zerop (DECL_SIZE (rli->prev_field))
1039 && host_integerp (DECL_SIZE (rli->prev_field), 0)
1040 && host_integerp (TYPE_SIZE (type), 0)
1041 && simple_cst_equal (TYPE_SIZE (type),
1042 TYPE_SIZE (TREE_TYPE (rli->prev_field))))
1044 /* We're in the middle of a run of equal type size fields; make
1045 sure we realign if we run out of bits. (Not decl size,
1047 HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 0);
1049 if (rli->remaining_in_alignment < bitsize)
1051 /* out of bits; bump up to next 'word'. */
1052 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1054 = size_binop (PLUS_EXPR, TYPE_SIZE (type),
1055 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1056 rli->prev_field = field;
1057 rli->remaining_in_alignment
1058 = tree_low_cst (TYPE_SIZE (type), 0);
1061 rli->remaining_in_alignment -= bitsize;
1065 /* End of a run: if leaving a run of bitfields of the same type
1066 size, we have to "use up" the rest of the bits of the type
1069 Compute the new position as the sum of the size for the prior
1070 type and where we first started working on that type.
1071 Note: since the beginning of the field was aligned then
1072 of course the end will be too. No round needed. */
1074 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1076 tree type_size = TYPE_SIZE (TREE_TYPE (rli->prev_field));
1079 = size_binop (PLUS_EXPR, type_size,
1080 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1083 /* We "use up" size zero fields; the code below should behave
1084 as if the prior field was not a bitfield. */
1087 /* Cause a new bitfield to be captured, either this time (if
1088 currently a bitfield) or next time we see one. */
1089 if (!DECL_BIT_FIELD_TYPE(field)
1090 || integer_zerop (DECL_SIZE (field)))
1091 rli->prev_field = NULL;
1094 rli->offset_align = tree_low_cst (TYPE_SIZE (type), 0);
1095 normalize_rli (rli);
1098 /* If we're starting a new run of same size type bitfields
1099 (or a run of non-bitfields), set up the "first of the run"
1102 That is, if the current field is not a bitfield, or if there
1103 was a prior bitfield the type sizes differ, or if there wasn't
1104 a prior bitfield the size of the current field is nonzero.
1106 Note: we must be sure to test ONLY the type size if there was
1107 a prior bitfield and ONLY for the current field being zero if
1110 if (!DECL_BIT_FIELD_TYPE (field)
1111 || ( prev_saved != NULL
1112 ? !simple_cst_equal (TYPE_SIZE (type),
1113 TYPE_SIZE (TREE_TYPE (prev_saved)))
1114 : !integer_zerop (DECL_SIZE (field)) ))
1116 /* Never smaller than a byte for compatibility. */
1117 unsigned int type_align = BITS_PER_UNIT;
1119 /* (When not a bitfield), we could be seeing a flex array (with
1120 no DECL_SIZE). Since we won't be using remaining_in_alignment
1121 until we see a bitfield (and come by here again) we just skip
1123 if (DECL_SIZE (field) != NULL
1124 && host_integerp (TYPE_SIZE (TREE_TYPE (field)), 0)
1125 && host_integerp (DECL_SIZE (field), 0))
1126 rli->remaining_in_alignment
1127 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field)), 0)
1128 - tree_low_cst (DECL_SIZE (field), 0);
1130 /* Now align (conventionally) for the new type. */
1131 if (!DECL_PACKED(field))
1132 type_align = MAX(TYPE_ALIGN (type), type_align);
1135 && DECL_BIT_FIELD_TYPE (prev_saved)
1136 /* If the previous bit-field is zero-sized, we've already
1137 accounted for its alignment needs (or ignored it, if
1138 appropriate) while placing it. */
1139 && ! integer_zerop (DECL_SIZE (prev_saved)))
1140 type_align = MAX (type_align,
1141 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1143 if (maximum_field_alignment != 0)
1144 type_align = MIN (type_align, maximum_field_alignment);
1146 rli->bitpos = round_up (rli->bitpos, type_align);
1148 /* If we really aligned, don't allow subsequent bitfields
1150 rli->prev_field = NULL;
1154 /* Offset so far becomes the position of this field after normalizing. */
1155 normalize_rli (rli);
1156 DECL_FIELD_OFFSET (field) = rli->offset;
1157 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1158 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1160 /* If this field ended up more aligned than we thought it would be (we
1161 approximate this by seeing if its position changed), lay out the field
1162 again; perhaps we can use an integral mode for it now. */
1163 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1164 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1165 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1166 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1167 actual_align = BIGGEST_ALIGNMENT;
1168 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1169 actual_align = (BITS_PER_UNIT
1170 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1171 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1173 actual_align = DECL_OFFSET_ALIGN (field);
1175 if (known_align != actual_align)
1176 layout_decl (field, actual_align);
1178 /* Only the MS bitfields use this. */
1179 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1180 rli->prev_field = field;
1182 /* Now add size of this field to the size of the record. If the size is
1183 not constant, treat the field as being a multiple of bytes and just
1184 adjust the offset, resetting the bit position. Otherwise, apportion the
1185 size amongst the bit position and offset. First handle the case of an
1186 unspecified size, which can happen when we have an invalid nested struct
1187 definition, such as struct j { struct j { int i; } }. The error message
1188 is printed in finish_struct. */
1189 if (DECL_SIZE (field) == 0)
1191 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1192 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1195 = size_binop (PLUS_EXPR, rli->offset,
1197 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1198 bitsize_unit_node)));
1200 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1201 rli->bitpos = bitsize_zero_node;
1202 rli->offset_align = MIN (rli->offset_align, desired_align);
1206 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1207 normalize_rli (rli);
1211 /* Assuming that all the fields have been laid out, this function uses
1212 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1213 indicated by RLI. */
1216 finalize_record_size (record_layout_info rli)
1218 tree unpadded_size, unpadded_size_unit;
1220 /* Now we want just byte and bit offsets, so set the offset alignment
1221 to be a byte and then normalize. */
1222 rli->offset_align = BITS_PER_UNIT;
1223 normalize_rli (rli);
1225 /* Determine the desired alignment. */
1226 #ifdef ROUND_TYPE_ALIGN
1227 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1230 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1233 /* Compute the size so far. Be sure to allow for extra bits in the
1234 size in bytes. We have guaranteed above that it will be no more
1235 than a single byte. */
1236 unpadded_size = rli_size_so_far (rli);
1237 unpadded_size_unit = rli_size_unit_so_far (rli);
1238 if (! integer_zerop (rli->bitpos))
1240 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1242 /* Round the size up to be a multiple of the required alignment. */
1243 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1244 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1245 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1247 if (warn_padded && TREE_CONSTANT (unpadded_size)
1248 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1249 warning ("padding struct size to alignment boundary");
1251 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1252 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1253 && TREE_CONSTANT (unpadded_size))
1257 #ifdef ROUND_TYPE_ALIGN
1259 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1261 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1264 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1265 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1267 TYPE_PACKED (rli->t) = 0;
1269 if (TYPE_NAME (rli->t))
1273 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1274 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1276 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1278 if (STRICT_ALIGNMENT)
1279 warning ("packed attribute causes inefficient alignment for `%s'", name);
1281 warning ("packed attribute is unnecessary for `%s'", name);
1285 if (STRICT_ALIGNMENT)
1286 warning ("packed attribute causes inefficient alignment");
1288 warning ("packed attribute is unnecessary");
1294 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1297 compute_record_mode (tree type)
1300 enum machine_mode mode = VOIDmode;
1302 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1303 However, if possible, we use a mode that fits in a register
1304 instead, in order to allow for better optimization down the
1306 TYPE_MODE (type) = BLKmode;
1308 if (! host_integerp (TYPE_SIZE (type), 1))
1311 /* A record which has any BLKmode members must itself be
1312 BLKmode; it can't go in a register. Unless the member is
1313 BLKmode only because it isn't aligned. */
1314 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1316 if (TREE_CODE (field) != FIELD_DECL)
1319 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1320 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1321 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))
1322 && !(TYPE_SIZE (TREE_TYPE (field)) != 0
1323 && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))))
1324 || ! host_integerp (bit_position (field), 1)
1325 || DECL_SIZE (field) == 0
1326 || ! host_integerp (DECL_SIZE (field), 1))
1329 /* If this field is the whole struct, remember its mode so
1330 that, say, we can put a double in a class into a DF
1331 register instead of forcing it to live in the stack. */
1332 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1333 mode = DECL_MODE (field);
1335 #ifdef MEMBER_TYPE_FORCES_BLK
1336 /* With some targets, eg. c4x, it is sub-optimal
1337 to access an aligned BLKmode structure as a scalar. */
1339 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1341 #endif /* MEMBER_TYPE_FORCES_BLK */
1344 /* If we only have one real field; use its mode. This only applies to
1345 RECORD_TYPE. This does not apply to unions. */
1346 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1347 TYPE_MODE (type) = mode;
1349 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1351 /* If structure's known alignment is less than what the scalar
1352 mode would need, and it matters, then stick with BLKmode. */
1353 if (TYPE_MODE (type) != BLKmode
1355 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1356 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1358 /* If this is the only reason this type is BLKmode, then
1359 don't force containing types to be BLKmode. */
1360 TYPE_NO_FORCE_BLK (type) = 1;
1361 TYPE_MODE (type) = BLKmode;
1365 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1369 finalize_type_size (tree type)
1371 /* Normally, use the alignment corresponding to the mode chosen.
1372 However, where strict alignment is not required, avoid
1373 over-aligning structures, since most compilers do not do this
1376 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1377 && (STRICT_ALIGNMENT
1378 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1379 && TREE_CODE (type) != QUAL_UNION_TYPE
1380 && TREE_CODE (type) != ARRAY_TYPE)))
1382 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1383 TYPE_USER_ALIGN (type) = 0;
1386 /* Do machine-dependent extra alignment. */
1387 #ifdef ROUND_TYPE_ALIGN
1389 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1392 /* If we failed to find a simple way to calculate the unit size
1393 of the type, find it by division. */
1394 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1395 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1396 result will fit in sizetype. We will get more efficient code using
1397 sizetype, so we force a conversion. */
1398 TYPE_SIZE_UNIT (type)
1399 = convert (sizetype,
1400 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1401 bitsize_unit_node));
1403 if (TYPE_SIZE (type) != 0)
1405 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1406 TYPE_SIZE_UNIT (type)
1407 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1410 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1411 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1412 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1413 if (TYPE_SIZE_UNIT (type) != 0
1414 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1415 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1417 /* Also layout any other variants of the type. */
1418 if (TYPE_NEXT_VARIANT (type)
1419 || type != TYPE_MAIN_VARIANT (type))
1422 /* Record layout info of this variant. */
1423 tree size = TYPE_SIZE (type);
1424 tree size_unit = TYPE_SIZE_UNIT (type);
1425 unsigned int align = TYPE_ALIGN (type);
1426 unsigned int user_align = TYPE_USER_ALIGN (type);
1427 enum machine_mode mode = TYPE_MODE (type);
1429 /* Copy it into all variants. */
1430 for (variant = TYPE_MAIN_VARIANT (type);
1432 variant = TYPE_NEXT_VARIANT (variant))
1434 TYPE_SIZE (variant) = size;
1435 TYPE_SIZE_UNIT (variant) = size_unit;
1436 TYPE_ALIGN (variant) = align;
1437 TYPE_USER_ALIGN (variant) = user_align;
1438 TYPE_MODE (variant) = mode;
1443 /* Do all of the work required to layout the type indicated by RLI,
1444 once the fields have been laid out. This function will call `free'
1445 for RLI, unless FREE_P is false. Passing a value other than false
1446 for FREE_P is bad practice; this option only exists to support the
1450 finish_record_layout (record_layout_info rli, int free_p)
1452 /* Compute the final size. */
1453 finalize_record_size (rli);
1455 /* Compute the TYPE_MODE for the record. */
1456 compute_record_mode (rli->t);
1458 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1459 finalize_type_size (rli->t);
1461 /* Lay out any static members. This is done now because their type
1462 may use the record's type. */
1463 while (rli->pending_statics)
1465 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1466 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1475 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1476 NAME, its fields are chained in reverse on FIELDS.
1478 If ALIGN_TYPE is non-null, it is given the same alignment as
1482 finish_builtin_struct (tree type, const char *name, tree fields,
1487 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1489 DECL_FIELD_CONTEXT (fields) = type;
1490 next = TREE_CHAIN (fields);
1491 TREE_CHAIN (fields) = tail;
1493 TYPE_FIELDS (type) = tail;
1497 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1498 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1502 #if 0 /* not yet, should get fixed properly later */
1503 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1505 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1507 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1508 layout_decl (TYPE_NAME (type), 0);
1511 /* Calculate the mode, size, and alignment for TYPE.
1512 For an array type, calculate the element separation as well.
1513 Record TYPE on the chain of permanent or temporary types
1514 so that dbxout will find out about it.
1516 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1517 layout_type does nothing on such a type.
1519 If the type is incomplete, its TYPE_SIZE remains zero. */
1522 layout_type (tree type)
1527 /* Do nothing if type has been laid out before. */
1528 if (TYPE_SIZE (type))
1531 switch (TREE_CODE (type))
1534 /* This kind of type is the responsibility
1535 of the language-specific code. */
1538 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1539 if (TYPE_PRECISION (type) == 0)
1540 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1542 /* ... fall through ... */
1547 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1548 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1549 TREE_UNSIGNED (type) = 1;
1551 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1553 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1554 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1558 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1559 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1560 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1564 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1566 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1567 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1568 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1570 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1571 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1578 subtype = TREE_TYPE (type);
1579 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1580 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1581 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1586 /* This is an incomplete type and so doesn't have a size. */
1587 TYPE_ALIGN (type) = 1;
1588 TYPE_USER_ALIGN (type) = 0;
1589 TYPE_MODE (type) = VOIDmode;
1593 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1594 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1595 /* A pointer might be MODE_PARTIAL_INT,
1596 but ptrdiff_t must be integral. */
1597 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1602 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1603 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1604 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1608 case REFERENCE_TYPE:
1611 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1612 && reference_types_internal)
1613 ? Pmode : TYPE_MODE (type));
1615 int nbits = GET_MODE_BITSIZE (mode);
1617 TYPE_SIZE (type) = bitsize_int (nbits);
1618 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1619 TREE_UNSIGNED (type) = 1;
1620 TYPE_PRECISION (type) = nbits;
1626 tree index = TYPE_DOMAIN (type);
1627 tree element = TREE_TYPE (type);
1629 build_pointer_type (element);
1631 /* We need to know both bounds in order to compute the size. */
1632 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1633 && TYPE_SIZE (element))
1635 tree ub = TYPE_MAX_VALUE (index);
1636 tree lb = TYPE_MIN_VALUE (index);
1640 /* The initial subtraction should happen in the original type so
1641 that (possible) negative values are handled appropriately. */
1642 length = size_binop (PLUS_EXPR, size_one_node,
1644 fold (build (MINUS_EXPR,
1648 /* Special handling for arrays of bits (for Chill). */
1649 element_size = TYPE_SIZE (element);
1650 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1651 && (integer_zerop (TYPE_MAX_VALUE (element))
1652 || integer_onep (TYPE_MAX_VALUE (element)))
1653 && host_integerp (TYPE_MIN_VALUE (element), 1))
1655 HOST_WIDE_INT maxvalue
1656 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1657 HOST_WIDE_INT minvalue
1658 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1660 if (maxvalue - minvalue == 1
1661 && (maxvalue == 1 || maxvalue == 0))
1662 element_size = integer_one_node;
1665 /* If neither bound is a constant and sizetype is signed, make
1666 sure the size is never negative. We should really do this
1667 if *either* bound is non-constant, but this is the best
1668 compromise between C and Ada. */
1669 if (! TREE_UNSIGNED (sizetype)
1670 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
1671 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
1672 length = size_binop (MAX_EXPR, length, size_zero_node);
1674 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1675 convert (bitsizetype, length));
1677 /* If we know the size of the element, calculate the total
1678 size directly, rather than do some division thing below.
1679 This optimization helps Fortran assumed-size arrays
1680 (where the size of the array is determined at runtime)
1682 Note that we can't do this in the case where the size of
1683 the elements is one bit since TYPE_SIZE_UNIT cannot be
1684 set correctly in that case. */
1685 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1686 TYPE_SIZE_UNIT (type)
1687 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1690 /* Now round the alignment and size,
1691 using machine-dependent criteria if any. */
1693 #ifdef ROUND_TYPE_ALIGN
1695 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1697 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1699 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1700 TYPE_MODE (type) = BLKmode;
1701 if (TYPE_SIZE (type) != 0
1702 #ifdef MEMBER_TYPE_FORCES_BLK
1703 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1705 /* BLKmode elements force BLKmode aggregate;
1706 else extract/store fields may lose. */
1707 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1708 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1710 /* One-element arrays get the component type's mode. */
1711 if (simple_cst_equal (TYPE_SIZE (type),
1712 TYPE_SIZE (TREE_TYPE (type))))
1713 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1716 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1718 if (TYPE_MODE (type) != BLKmode
1719 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1720 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1721 && TYPE_MODE (type) != BLKmode)
1723 TYPE_NO_FORCE_BLK (type) = 1;
1724 TYPE_MODE (type) = BLKmode;
1732 case QUAL_UNION_TYPE:
1735 record_layout_info rli;
1737 /* Initialize the layout information. */
1738 rli = start_record_layout (type);
1740 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1741 in the reverse order in building the COND_EXPR that denotes
1742 its size. We reverse them again later. */
1743 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1744 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1746 /* Place all the fields. */
1747 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1748 place_field (rli, field);
1750 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1751 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1753 if (lang_adjust_rli)
1754 (*lang_adjust_rli) (rli);
1756 /* Finish laying out the record. */
1757 finish_record_layout (rli, /*free_p=*/true);
1761 case SET_TYPE: /* Used by Chill and Pascal. */
1762 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1763 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1767 #ifndef SET_WORD_SIZE
1768 #define SET_WORD_SIZE BITS_PER_WORD
1770 unsigned int alignment
1771 = set_alignment ? set_alignment : SET_WORD_SIZE;
1772 HOST_WIDE_INT size_in_bits
1773 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), 0)
1774 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0) + 1);
1775 HOST_WIDE_INT rounded_size
1776 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1778 if (rounded_size > (int) alignment)
1779 TYPE_MODE (type) = BLKmode;
1781 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1783 TYPE_SIZE (type) = bitsize_int (rounded_size);
1784 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1785 TYPE_ALIGN (type) = alignment;
1786 TYPE_USER_ALIGN (type) = 0;
1787 TYPE_PRECISION (type) = size_in_bits;
1792 /* The size may vary in different languages, so the language front end
1793 should fill in the size. */
1794 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1795 TYPE_USER_ALIGN (type) = 0;
1796 TYPE_MODE (type) = BLKmode;
1803 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1804 records and unions, finish_record_layout already called this
1806 if (TREE_CODE (type) != RECORD_TYPE
1807 && TREE_CODE (type) != UNION_TYPE
1808 && TREE_CODE (type) != QUAL_UNION_TYPE)
1809 finalize_type_size (type);
1811 /* If this type is created before sizetype has been permanently set,
1812 record it so set_sizetype can fix it up. */
1814 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1816 /* If an alias set has been set for this aggregate when it was incomplete,
1817 force it into alias set 0.
1818 This is too conservative, but we cannot call record_component_aliases
1819 here because some frontends still change the aggregates after
1821 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1822 TYPE_ALIAS_SET (type) = 0;
1825 /* Create and return a type for signed integers of PRECISION bits. */
1828 make_signed_type (int precision)
1830 tree type = make_node (INTEGER_TYPE);
1832 TYPE_PRECISION (type) = precision;
1834 fixup_signed_type (type);
1838 /* Create and return a type for unsigned integers of PRECISION bits. */
1841 make_unsigned_type (int precision)
1843 tree type = make_node (INTEGER_TYPE);
1845 TYPE_PRECISION (type) = precision;
1847 fixup_unsigned_type (type);
1851 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1852 value to enable integer types to be created. */
1855 initialize_sizetypes (void)
1857 tree t = make_node (INTEGER_TYPE);
1859 /* Set this so we do something reasonable for the build_int_2 calls
1861 integer_type_node = t;
1863 TYPE_MODE (t) = SImode;
1864 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1865 TYPE_USER_ALIGN (t) = 0;
1866 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1867 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1868 TREE_UNSIGNED (t) = 1;
1869 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1870 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1871 TYPE_IS_SIZETYPE (t) = 1;
1873 /* 1000 avoids problems with possible overflow and is certainly
1874 larger than any size value we'd want to be storing. */
1875 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1877 /* These two must be different nodes because of the caching done in
1880 bitsizetype = copy_node (t);
1881 integer_type_node = 0;
1884 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1885 Also update the type of any standard type's sizes made so far. */
1888 set_sizetype (tree type)
1890 int oprecision = TYPE_PRECISION (type);
1891 /* The *bitsizetype types use a precision that avoids overflows when
1892 calculating signed sizes / offsets in bits. However, when
1893 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1895 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1896 2 * HOST_BITS_PER_WIDE_INT);
1903 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1904 sizetype = copy_node (type);
1905 TYPE_DOMAIN (sizetype) = type;
1906 TYPE_IS_SIZETYPE (sizetype) = 1;
1907 bitsizetype = make_node (INTEGER_TYPE);
1908 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1909 TYPE_PRECISION (bitsizetype) = precision;
1910 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1912 if (TREE_UNSIGNED (type))
1913 fixup_unsigned_type (bitsizetype);
1915 fixup_signed_type (bitsizetype);
1917 layout_type (bitsizetype);
1919 if (TREE_UNSIGNED (type))
1921 usizetype = sizetype;
1922 ubitsizetype = bitsizetype;
1923 ssizetype = copy_node (make_signed_type (oprecision));
1924 sbitsizetype = copy_node (make_signed_type (precision));
1928 ssizetype = sizetype;
1929 sbitsizetype = bitsizetype;
1930 usizetype = copy_node (make_unsigned_type (oprecision));
1931 ubitsizetype = copy_node (make_unsigned_type (precision));
1934 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1936 /* Show is a sizetype, is a main type, and has no pointers to it. */
1937 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1939 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1940 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1941 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1942 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1943 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1946 /* Go down each of the types we already made and set the proper type
1947 for the sizes in them. */
1948 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1950 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE
1951 && TREE_CODE (TREE_VALUE (t)) != BOOLEAN_TYPE)
1954 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1955 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1958 early_type_list = 0;
1962 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1963 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1964 for TYPE, based on the PRECISION and whether or not the TYPE
1965 IS_UNSIGNED. PRECISION need not correspond to a width supported
1966 natively by the hardware; for example, on a machine with 8-bit,
1967 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1971 set_min_and_max_values_for_integral_type (tree type,
1980 min_value = build_int_2 (0, 0);
1982 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1983 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1984 precision - HOST_BITS_PER_WIDE_INT > 0
1985 ? ((unsigned HOST_WIDE_INT) ~0
1986 >> (HOST_BITS_PER_WIDE_INT
1987 - (precision - HOST_BITS_PER_WIDE_INT)))
1993 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1994 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1995 (((HOST_WIDE_INT) (-1)
1996 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1997 ? precision - HOST_BITS_PER_WIDE_INT - 1
2000 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2001 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2002 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2003 ? (((HOST_WIDE_INT) 1
2004 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2008 TREE_TYPE (min_value) = type;
2009 TREE_TYPE (max_value) = type;
2010 TYPE_MIN_VALUE (type) = min_value;
2011 TYPE_MAX_VALUE (type) = max_value;
2014 /* Set the extreme values of TYPE based on its precision in bits,
2015 then lay it out. Used when make_signed_type won't do
2016 because the tree code is not INTEGER_TYPE.
2017 E.g. for Pascal, when the -fsigned-char option is given. */
2020 fixup_signed_type (tree type)
2022 int precision = TYPE_PRECISION (type);
2024 /* We can not represent properly constants greater then
2025 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2026 as they are used by i386 vector extensions and friends. */
2027 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2028 precision = HOST_BITS_PER_WIDE_INT * 2;
2030 set_min_and_max_values_for_integral_type (type, precision,
2031 /*is_unsigned=*/false);
2033 /* Lay out the type: set its alignment, size, etc. */
2037 /* Set the extreme values of TYPE based on its precision in bits,
2038 then lay it out. This is used both in `make_unsigned_type'
2039 and for enumeral types. */
2042 fixup_unsigned_type (tree type)
2044 int precision = TYPE_PRECISION (type);
2046 /* We can not represent properly constants greater then
2047 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2048 as they are used by i386 vector extensions and friends. */
2049 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2050 precision = HOST_BITS_PER_WIDE_INT * 2;
2052 set_min_and_max_values_for_integral_type (type, precision,
2053 /*is_unsigned=*/true);
2055 /* Lay out the type: set its alignment, size, etc. */
2059 /* Find the best machine mode to use when referencing a bit field of length
2060 BITSIZE bits starting at BITPOS.
2062 The underlying object is known to be aligned to a boundary of ALIGN bits.
2063 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2064 larger than LARGEST_MODE (usually SImode).
2066 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2067 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2068 mode meeting these conditions.
2070 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2071 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2072 all the conditions. */
2075 get_best_mode (int bitsize, int bitpos, unsigned int align,
2076 enum machine_mode largest_mode, int volatilep)
2078 enum machine_mode mode;
2079 unsigned int unit = 0;
2081 /* Find the narrowest integer mode that contains the bit field. */
2082 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2083 mode = GET_MODE_WIDER_MODE (mode))
2085 unit = GET_MODE_BITSIZE (mode);
2086 if ((bitpos % unit) + bitsize <= unit)
2090 if (mode == VOIDmode
2091 /* It is tempting to omit the following line
2092 if STRICT_ALIGNMENT is true.
2093 But that is incorrect, since if the bitfield uses part of 3 bytes
2094 and we use a 4-byte mode, we could get a spurious segv
2095 if the extra 4th byte is past the end of memory.
2096 (Though at least one Unix compiler ignores this problem:
2097 that on the Sequent 386 machine. */
2098 || MIN (unit, BIGGEST_ALIGNMENT) > align
2099 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2102 if (SLOW_BYTE_ACCESS && ! volatilep)
2104 enum machine_mode wide_mode = VOIDmode, tmode;
2106 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2107 tmode = GET_MODE_WIDER_MODE (tmode))
2109 unit = GET_MODE_BITSIZE (tmode);
2110 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2111 && unit <= BITS_PER_WORD
2112 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2113 && (largest_mode == VOIDmode
2114 || unit <= GET_MODE_BITSIZE (largest_mode)))
2118 if (wide_mode != VOIDmode)
2125 #include "gt-stor-layout.h"