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 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
36 #include "langhooks.h"
38 /* Set to one when set_sizetype has been called. */
39 static int sizetype_set;
41 /* List of types created before set_sizetype has been called. We do not
42 make this a GGC root since we want these nodes to be reclaimed. */
43 static tree early_type_list;
45 /* Data type for the expressions representing sizes of data types.
46 It is the first integer type laid out. */
47 tree sizetype_tab[(int) TYPE_KIND_LAST];
49 /* If nonzero, this is an upper limit on alignment of structure fields.
50 The value is measured in bits. */
51 unsigned int maximum_field_alignment;
53 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
54 May be overridden by front-ends. */
55 unsigned int set_alignment = 0;
57 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
58 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
59 called only by a front end. */
60 static int reference_types_internal = 0;
62 static void finalize_record_size PARAMS ((record_layout_info));
63 static void finalize_type_size PARAMS ((tree));
64 static void place_union_field PARAMS ((record_layout_info, tree));
65 static int excess_unit_span PARAMS ((HOST_WIDE_INT, HOST_WIDE_INT,
66 HOST_WIDE_INT, HOST_WIDE_INT,
68 static unsigned int update_alignment_for_field
69 PARAMS ((record_layout_info, tree,
71 extern void debug_rli PARAMS ((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 ()
88 reference_types_internal = 1;
91 /* Get a list of all the objects put on the pending sizes list. */
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 (expr)
115 for (t = pending_sizes; t; t = TREE_CHAIN (t))
116 if (TREE_VALUE (t) == expr)
121 /* Add EXPR to the pending sizes list. */
124 put_pending_size (expr)
127 /* Strip any simple arithmetic from EXPR to see if it has an underlying
129 while (TREE_CODE_CLASS (TREE_CODE (expr)) == '1'
130 || (TREE_CODE_CLASS (TREE_CODE (expr)) == '2'
131 && TREE_CONSTANT (TREE_OPERAND (expr, 1))))
132 expr = TREE_OPERAND (expr, 0);
134 if (TREE_CODE (expr) == SAVE_EXPR)
135 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
138 /* Put a chain of objects into the pending sizes list, which must be
142 put_pending_sizes (chain)
148 pending_sizes = chain;
151 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
152 to serve as the actual size-expression for a type or decl. */
158 /* If the language-processor is to take responsibility for variable-sized
159 items (e.g., languages which have elaboration procedures like Ada),
160 just return SIZE unchanged. Likewise for self-referential sizes and
162 if (TREE_CONSTANT (size)
163 || (*lang_hooks.decls.global_bindings_p) () < 0
164 || contains_placeholder_p (size))
167 size = 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 (size) == SAVE_EXPR)
178 SAVE_EXPR_PERSISTENT_P (size) = 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 /* NULL_RTX is not defined; neither is the rtx type.
192 Also, we would like to pass const0_rtx here, but don't have it. */
193 expand_expr (size, expand_expr (integer_zero_node, NULL_RTX, VOIDmode, 0),
195 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
196 /* The front-end doesn't want us to keep a list of the expressions
197 that determine sizes for variable size objects. */
200 put_pending_size (size);
205 #ifndef MAX_FIXED_MODE_SIZE
206 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
209 /* Return the machine mode to use for a nonscalar of SIZE bits.
210 The mode must be in class CLASS, and have exactly that many bits.
211 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
215 mode_for_size (size, class, limit)
217 enum mode_class class;
220 enum machine_mode mode;
222 if (limit && size > MAX_FIXED_MODE_SIZE)
225 /* Get the first mode which has this size, in the specified class. */
226 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
227 mode = GET_MODE_WIDER_MODE (mode))
228 if (GET_MODE_BITSIZE (mode) == size)
234 /* Similar, except passed a tree node. */
237 mode_for_size_tree (size, class, limit)
239 enum mode_class class;
242 if (TREE_CODE (size) != INTEGER_CST
243 /* What we really want to say here is that the size can fit in a
244 host integer, but we know there's no way we'd find a mode for
245 this many bits, so there's no point in doing the precise test. */
246 || compare_tree_int (size, 1000) > 0)
249 return mode_for_size (TREE_INT_CST_LOW (size), class, limit);
252 /* Similar, but never return BLKmode; return the narrowest mode that
253 contains at least the requested number of bits. */
256 smallest_mode_for_size (size, class)
258 enum mode_class class;
260 enum machine_mode mode;
262 /* Get the first mode which has at least this size, in the
264 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
265 mode = GET_MODE_WIDER_MODE (mode))
266 if (GET_MODE_BITSIZE (mode) >= size)
272 /* Find an integer mode of the exact same size, or BLKmode on failure. */
275 int_mode_for_mode (mode)
276 enum machine_mode mode;
278 switch (GET_MODE_CLASS (mode))
281 case MODE_PARTIAL_INT:
284 case MODE_COMPLEX_INT:
285 case MODE_COMPLEX_FLOAT:
287 case MODE_VECTOR_INT:
288 case MODE_VECTOR_FLOAT:
289 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
296 /* ... fall through ... */
306 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
307 This can only be applied to objects of a sizetype. */
310 round_up (value, divisor)
314 tree arg = size_int_type (divisor, TREE_TYPE (value));
316 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
319 /* Likewise, but round down. */
322 round_down (value, divisor)
326 tree arg = size_int_type (divisor, TREE_TYPE (value));
328 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
331 /* Set the size, mode and alignment of a ..._DECL node.
332 TYPE_DECL does need this for C++.
333 Note that LABEL_DECL and CONST_DECL nodes do not need this,
334 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
335 Don't call layout_decl for them.
337 KNOWN_ALIGN is the amount of alignment we can assume this
338 decl has with no special effort. It is relevant only for FIELD_DECLs
339 and depends on the previous fields.
340 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
341 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
342 the record will be aligned to suit. */
345 layout_decl (decl, known_align)
347 unsigned int known_align;
349 tree type = TREE_TYPE (decl);
350 enum tree_code code = TREE_CODE (decl);
352 if (code == CONST_DECL)
354 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
355 && code != TYPE_DECL && code != FIELD_DECL)
358 if (type == error_mark_node)
359 type = void_type_node;
361 /* Usually the size and mode come from the data type without change,
362 however, the front-end may set the explicit width of the field, so its
363 size may not be the same as the size of its type. This happens with
364 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
365 also happens with other fields. For example, the C++ front-end creates
366 zero-sized fields corresponding to empty base classes, and depends on
367 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
368 size in bytes from the size in bits. If we have already set the mode,
369 don't set it again since we can be called twice for FIELD_DECLs. */
371 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
372 if (DECL_MODE (decl) == VOIDmode)
373 DECL_MODE (decl) = TYPE_MODE (type);
375 if (DECL_SIZE (decl) == 0)
377 DECL_SIZE (decl) = TYPE_SIZE (type);
378 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
381 DECL_SIZE_UNIT (decl)
382 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
385 /* Force alignment required for the data type.
386 But if the decl itself wants greater alignment, don't override that.
387 Likewise, if the decl is packed, don't override it. */
388 if (! (code == FIELD_DECL && DECL_BIT_FIELD (decl))
389 && (DECL_ALIGN (decl) == 0
390 || (! (code == FIELD_DECL && DECL_PACKED (decl))
391 && TYPE_ALIGN (type) > DECL_ALIGN (decl))))
393 DECL_ALIGN (decl) = TYPE_ALIGN (type);
394 DECL_USER_ALIGN (decl) = 0;
397 /* For fields, set the bit field type and update the alignment. */
398 if (code == FIELD_DECL)
400 DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
401 if (maximum_field_alignment != 0)
402 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
404 /* If the field is of variable size, we can't misalign it since we
405 have no way to make a temporary to align the result. But this
406 isn't an issue if the decl is not addressable. Likewise if it
407 is of unknown size. */
408 else if (DECL_PACKED (decl)
409 && (DECL_NONADDRESSABLE_P (decl)
410 || DECL_SIZE_UNIT (decl) == 0
411 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
413 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
414 DECL_USER_ALIGN (decl) = 0;
418 /* See if we can use an ordinary integer mode for a bit-field.
419 Conditions are: a fixed size that is correct for another mode
420 and occupying a complete byte or bytes on proper boundary. */
421 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
422 && TYPE_SIZE (type) != 0
423 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
424 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
426 enum machine_mode xmode
427 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
429 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
431 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
433 DECL_MODE (decl) = xmode;
434 DECL_BIT_FIELD (decl) = 0;
438 /* Turn off DECL_BIT_FIELD if we won't need it set. */
439 if (code == FIELD_DECL && DECL_BIT_FIELD (decl)
440 && TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
441 && known_align >= TYPE_ALIGN (type)
442 && DECL_ALIGN (decl) >= TYPE_ALIGN (type)
443 && DECL_SIZE_UNIT (decl) != 0)
444 DECL_BIT_FIELD (decl) = 0;
446 /* Evaluate nonconstant size only once, either now or as soon as safe. */
447 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
448 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
449 if (DECL_SIZE_UNIT (decl) != 0
450 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
451 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
453 /* If requested, warn about definitions of large data objects. */
455 && (code == VAR_DECL || code == PARM_DECL)
456 && ! DECL_EXTERNAL (decl))
458 tree size = DECL_SIZE_UNIT (decl);
460 if (size != 0 && TREE_CODE (size) == INTEGER_CST
461 && compare_tree_int (size, larger_than_size) > 0)
463 unsigned int size_as_int = TREE_INT_CST_LOW (size);
465 if (compare_tree_int (size, size_as_int) == 0)
466 warning_with_decl (decl, "size of `%s' is %d bytes", size_as_int);
468 warning_with_decl (decl, "size of `%s' is larger than %d bytes",
474 /* Hook for a front-end function that can modify the record layout as needed
475 immediately before it is finalized. */
477 void (*lang_adjust_rli) PARAMS ((record_layout_info)) = 0;
480 set_lang_adjust_rli (f)
481 void (*f) PARAMS ((record_layout_info));
486 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
487 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
488 is to be passed to all other layout functions for this record. It is the
489 responsibility of the caller to call `free' for the storage returned.
490 Note that garbage collection is not permitted until we finish laying
494 start_record_layout (t)
497 record_layout_info rli
498 = (record_layout_info) xmalloc (sizeof (struct record_layout_info_s));
502 /* If the type has a minimum specified alignment (via an attribute
503 declaration, for example) use it -- otherwise, start with a
504 one-byte alignment. */
505 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
506 rli->unpacked_align = rli->unpadded_align = rli->record_align;
507 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
509 #ifdef STRUCTURE_SIZE_BOUNDARY
510 /* Packed structures don't need to have minimum size. */
511 if (! TYPE_PACKED (t))
512 rli->record_align = MAX (rli->record_align, STRUCTURE_SIZE_BOUNDARY);
515 rli->offset = size_zero_node;
516 rli->bitpos = bitsize_zero_node;
518 rli->pending_statics = 0;
519 rli->packed_maybe_necessary = 0;
524 /* These four routines perform computations that convert between
525 the offset/bitpos forms and byte and bit offsets. */
528 bit_from_pos (offset, bitpos)
531 return size_binop (PLUS_EXPR, bitpos,
532 size_binop (MULT_EXPR, convert (bitsizetype, offset),
537 byte_from_pos (offset, bitpos)
540 return size_binop (PLUS_EXPR, offset,
542 size_binop (TRUNC_DIV_EXPR, bitpos,
543 bitsize_unit_node)));
547 pos_from_bit (poffset, pbitpos, off_align, pos)
548 tree *poffset, *pbitpos;
549 unsigned int off_align;
552 *poffset = size_binop (MULT_EXPR,
554 size_binop (FLOOR_DIV_EXPR, pos,
555 bitsize_int (off_align))),
556 size_int (off_align / BITS_PER_UNIT));
557 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
560 /* Given a pointer to bit and byte offsets and an offset alignment,
561 normalize the offsets so they are within the alignment. */
564 normalize_offset (poffset, pbitpos, off_align)
565 tree *poffset, *pbitpos;
566 unsigned int off_align;
568 /* If the bit position is now larger than it should be, adjust it
570 if (compare_tree_int (*pbitpos, off_align) >= 0)
572 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
573 bitsize_int (off_align));
576 = size_binop (PLUS_EXPR, *poffset,
577 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
578 size_int (off_align / BITS_PER_UNIT)));
581 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
585 /* Print debugging information about the information in RLI. */
589 record_layout_info rli;
591 print_node_brief (stderr, "type", rli->t, 0);
592 print_node_brief (stderr, "\noffset", rli->offset, 0);
593 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
595 fprintf (stderr, "\naligns: rec = %u, unpack = %u, unpad = %u, off = %u\n",
596 rli->record_align, rli->unpacked_align, rli->unpadded_align,
598 if (rli->packed_maybe_necessary)
599 fprintf (stderr, "packed may be necessary\n");
601 if (rli->pending_statics)
603 fprintf (stderr, "pending statics:\n");
604 debug_tree (rli->pending_statics);
608 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
609 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
613 record_layout_info rli;
615 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
618 /* Returns the size in bytes allocated so far. */
621 rli_size_unit_so_far (rli)
622 record_layout_info rli;
624 return byte_from_pos (rli->offset, rli->bitpos);
627 /* Returns the size in bits allocated so far. */
630 rli_size_so_far (rli)
631 record_layout_info rli;
633 return bit_from_pos (rli->offset, rli->bitpos);
636 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
637 the next available location is given by KNOWN_ALIGN. Update the
638 variable alignment fields in RLI, and return the alignment to give
642 update_alignment_for_field (rli, field, known_align)
643 record_layout_info rli;
645 unsigned int known_align;
647 /* The alignment required for FIELD. */
648 unsigned int desired_align;
649 /* The type of this field. */
650 tree type = TREE_TYPE (field);
651 /* True if the field was explicitly aligned by the user. */
654 /* Lay out the field so we know what alignment it needs. For a
655 packed field, use the alignment as specified, disregarding what
656 the type would want. */
657 desired_align = DECL_ALIGN (field);
658 user_align = DECL_USER_ALIGN (field);
659 layout_decl (field, known_align);
660 if (! DECL_PACKED (field))
662 desired_align = DECL_ALIGN (field);
663 user_align = DECL_USER_ALIGN (field);
666 /* Some targets (i.e. i386, VMS) limit struct field alignment
667 to a lower boundary than alignment of variables unless
668 it was overridden by attribute aligned. */
669 #ifdef BIGGEST_FIELD_ALIGNMENT
672 = MIN (desired_align, (unsigned) BIGGEST_FIELD_ALIGNMENT);
675 #ifdef ADJUST_FIELD_ALIGN
677 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
680 /* Record must have at least as much alignment as any field.
681 Otherwise, the alignment of the field within the record is
683 if ((* targetm.ms_bitfield_layout_p) (rli->t)
684 && type != error_mark_node
685 && DECL_BIT_FIELD_TYPE (field)
686 && ! integer_zerop (TYPE_SIZE (type)))
688 /* Here, the alignment of the underlying type of a bitfield can
689 affect the alignment of a record; even a zero-sized field
690 can do this. The alignment should be to the alignment of
691 the type, except that for zero-size bitfields this only
692 applies if there was an immediately prior, nonzero-size
693 bitfield. (That's the way it is, experimentally.) */
694 if (! integer_zerop (DECL_SIZE (field))
695 ? ! DECL_PACKED (field)
697 && DECL_BIT_FIELD_TYPE (rli->prev_field)
698 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
700 unsigned int type_align = TYPE_ALIGN (type);
701 type_align = MAX (type_align, desired_align);
702 if (maximum_field_alignment != 0)
703 type_align = MIN (type_align, maximum_field_alignment);
704 rli->record_align = MAX (rli->record_align, type_align);
705 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
706 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
712 #ifdef PCC_BITFIELD_TYPE_MATTERS
713 if (PCC_BITFIELD_TYPE_MATTERS && type != error_mark_node
714 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
715 && DECL_BIT_FIELD_TYPE (field)
716 && ! integer_zerop (TYPE_SIZE (type)))
718 /* For these machines, a zero-length field does not
719 affect the alignment of the structure as a whole.
720 It does, however, affect the alignment of the next field
721 within the structure. */
722 if (! integer_zerop (DECL_SIZE (field)))
723 rli->record_align = MAX (rli->record_align, desired_align);
724 else if (! DECL_PACKED (field))
726 desired_align = TYPE_ALIGN (type);
727 desired_align = ADJUST_FIELD_ALIGN (field, desired_align);
730 /* A named bit field of declared type `int'
731 forces the entire structure to have `int' alignment. */
732 if (DECL_NAME (field) != 0)
734 unsigned int type_align = TYPE_ALIGN (type);
736 #ifdef ADJUST_FIELD_ALIGN
737 if (! TYPE_USER_ALIGN (type))
738 type_align = ADJUST_FIELD_ALIGN (field, type_align);
741 if (maximum_field_alignment != 0)
742 type_align = MIN (type_align, maximum_field_alignment);
743 else if (DECL_PACKED (field))
744 type_align = MIN (type_align, BITS_PER_UNIT);
746 rli->record_align = MAX (rli->record_align, type_align);
747 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
749 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
750 user_align |= TYPE_USER_ALIGN (type);
756 rli->record_align = MAX (rli->record_align, desired_align);
757 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
758 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
761 TYPE_USER_ALIGN (rli->t) |= user_align;
763 return desired_align;
766 /* Called from place_field to handle unions. */
769 place_union_field (rli, field)
770 record_layout_info rli;
773 update_alignment_for_field (rli, field, /*known_align=*/0);
775 DECL_FIELD_OFFSET (field) = size_zero_node;
776 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
777 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
779 /* We assume the union's size will be a multiple of a byte so we don't
780 bother with BITPOS. */
781 if (TREE_CODE (rli->t) == UNION_TYPE)
782 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
783 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
784 rli->offset = fold (build (COND_EXPR, sizetype,
785 DECL_QUALIFIER (field),
786 DECL_SIZE_UNIT (field), rli->offset));
789 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
790 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
791 units of alignment than the underlying TYPE. */
793 excess_unit_span (byte_offset, bit_offset, size, align, type)
794 HOST_WIDE_INT byte_offset, bit_offset, size, align;
797 /* Note that the calculation of OFFSET might overflow; we calculate it so
798 that we still get the right result as long as ALIGN is a power of two. */
799 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
801 offset = offset % align;
802 return ((offset + size + align - 1) / align
803 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
807 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
808 is a FIELD_DECL to be added after those fields already present in
809 T. (FIELD is not actually added to the TYPE_FIELDS list here;
810 callers that desire that behavior must manually perform that step.) */
813 place_field (rli, field)
814 record_layout_info rli;
817 /* The alignment required for FIELD. */
818 unsigned int desired_align;
819 /* The alignment FIELD would have if we just dropped it into the
820 record as it presently stands. */
821 unsigned int known_align;
822 unsigned int actual_align;
823 /* The type of this field. */
824 tree type = TREE_TYPE (field);
826 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
829 /* If FIELD is static, then treat it like a separate variable, not
830 really like a structure field. If it is a FUNCTION_DECL, it's a
831 method. In both cases, all we do is lay out the decl, and we do
832 it *after* the record is laid out. */
833 if (TREE_CODE (field) == VAR_DECL)
835 rli->pending_statics = tree_cons (NULL_TREE, field,
836 rli->pending_statics);
840 /* Enumerators and enum types which are local to this class need not
841 be laid out. Likewise for initialized constant fields. */
842 else if (TREE_CODE (field) != FIELD_DECL)
845 /* Unions are laid out very differently than records, so split
846 that code off to another function. */
847 else if (TREE_CODE (rli->t) != RECORD_TYPE)
849 place_union_field (rli, field);
853 /* Work out the known alignment so far. Note that A & (-A) is the
854 value of the least-significant bit in A that is one. */
855 if (! integer_zerop (rli->bitpos))
856 known_align = (tree_low_cst (rli->bitpos, 1)
857 & - tree_low_cst (rli->bitpos, 1));
858 else if (integer_zerop (rli->offset))
859 known_align = BIGGEST_ALIGNMENT;
860 else if (host_integerp (rli->offset, 1))
861 known_align = (BITS_PER_UNIT
862 * (tree_low_cst (rli->offset, 1)
863 & - tree_low_cst (rli->offset, 1)));
865 known_align = rli->offset_align;
867 desired_align = update_alignment_for_field (rli, field, known_align);
869 if (warn_packed && DECL_PACKED (field))
871 if (known_align > TYPE_ALIGN (type))
873 if (TYPE_ALIGN (type) > desired_align)
875 if (STRICT_ALIGNMENT)
876 warning_with_decl (field, "packed attribute causes inefficient alignment for `%s'");
878 warning_with_decl (field, "packed attribute is unnecessary for `%s'");
882 rli->packed_maybe_necessary = 1;
885 /* Does this field automatically have alignment it needs by virtue
886 of the fields that precede it and the record's own alignment? */
887 if (known_align < desired_align)
889 /* No, we need to skip space before this field.
890 Bump the cumulative size to multiple of field alignment. */
893 warning_with_decl (field, "padding struct to align `%s'");
895 /* If the alignment is still within offset_align, just align
897 if (desired_align < rli->offset_align)
898 rli->bitpos = round_up (rli->bitpos, desired_align);
901 /* First adjust OFFSET by the partial bits, then align. */
903 = size_binop (PLUS_EXPR, rli->offset,
905 size_binop (CEIL_DIV_EXPR, rli->bitpos,
906 bitsize_unit_node)));
907 rli->bitpos = bitsize_zero_node;
909 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
912 if (! TREE_CONSTANT (rli->offset))
913 rli->offset_align = desired_align;
917 /* Handle compatibility with PCC. Note that if the record has any
918 variable-sized fields, we need not worry about compatibility. */
919 #ifdef PCC_BITFIELD_TYPE_MATTERS
920 if (PCC_BITFIELD_TYPE_MATTERS
921 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
922 && TREE_CODE (field) == FIELD_DECL
923 && type != error_mark_node
924 && DECL_BIT_FIELD (field)
925 && ! DECL_PACKED (field)
926 && maximum_field_alignment == 0
927 && ! integer_zerop (DECL_SIZE (field))
928 && host_integerp (DECL_SIZE (field), 1)
929 && host_integerp (rli->offset, 1)
930 && host_integerp (TYPE_SIZE (type), 1))
932 unsigned int type_align = TYPE_ALIGN (type);
933 tree dsize = DECL_SIZE (field);
934 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
935 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
936 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
938 #ifdef ADJUST_FIELD_ALIGN
939 if (! TYPE_USER_ALIGN (type))
940 type_align = ADJUST_FIELD_ALIGN (field, type_align);
943 /* A bit field may not span more units of alignment of its type
944 than its type itself. Advance to next boundary if necessary. */
945 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
946 rli->bitpos = round_up (rli->bitpos, type_align);
948 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
952 #ifdef BITFIELD_NBYTES_LIMITED
953 if (BITFIELD_NBYTES_LIMITED
954 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
955 && TREE_CODE (field) == FIELD_DECL
956 && type != error_mark_node
957 && DECL_BIT_FIELD_TYPE (field)
958 && ! DECL_PACKED (field)
959 && ! integer_zerop (DECL_SIZE (field))
960 && host_integerp (DECL_SIZE (field), 1)
961 && host_integerp (rli->offset, 1)
962 && host_integerp (TYPE_SIZE (type), 1))
964 unsigned int type_align = TYPE_ALIGN (type);
965 tree dsize = DECL_SIZE (field);
966 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
967 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
968 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
970 #ifdef ADJUST_FIELD_ALIGN
971 if (! TYPE_USER_ALIGN (type))
972 type_align = ADJUST_FIELD_ALIGN (field, type_align);
975 if (maximum_field_alignment != 0)
976 type_align = MIN (type_align, maximum_field_alignment);
977 /* ??? This test is opposite the test in the containing if
978 statement, so this code is unreachable currently. */
979 else if (DECL_PACKED (field))
980 type_align = MIN (type_align, BITS_PER_UNIT);
982 /* A bit field may not span the unit of alignment of its type.
983 Advance to next boundary if necessary. */
984 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
985 rli->bitpos = round_up (rli->bitpos, type_align);
987 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
991 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
993 When a bit field is inserted into a packed record, the whole
994 size of the underlying type is used by one or more same-size
995 adjacent bitfields. (That is, if its long:3, 32 bits is
996 used in the record, and any additional adjacent long bitfields are
997 packed into the same chunk of 32 bits. However, if the size
998 changes, a new field of that size is allocated.) In an unpacked
999 record, this is the same as using alignment, but not eqivalent
1002 Note: for compatability, we use the type size, not the type alignment
1003 to determine alignment, since that matches the documentation */
1005 if ((* targetm.ms_bitfield_layout_p) (rli->t)
1006 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1007 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1009 /* At this point, either the prior or current are bitfields,
1010 (possibly both), and we're dealing with MS packing. */
1011 tree prev_saved = rli->prev_field;
1013 /* Is the prior field a bitfield? If so, handle "runs" of same
1014 type size fields. */
1015 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1017 /* If both are bitfields, nonzero, and the same size, this is
1018 the middle of a run. Zero declared size fields are special
1019 and handled as "end of run". (Note: it's nonzero declared
1020 size, but equal type sizes!) (Since we know that both
1021 the current and previous fields are bitfields by the
1022 time we check it, DECL_SIZE must be present for both.) */
1023 if (DECL_BIT_FIELD_TYPE (field)
1024 && !integer_zerop (DECL_SIZE (field))
1025 && !integer_zerop (DECL_SIZE (rli->prev_field))
1026 && simple_cst_equal (TYPE_SIZE (type),
1027 TYPE_SIZE (TREE_TYPE (rli->prev_field))) )
1029 /* We're in the middle of a run of equal type size fields; make
1030 sure we realign if we run out of bits. (Not decl size,
1032 int bitsize = TREE_INT_CST_LOW (DECL_SIZE (field));
1033 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1035 if (rli->remaining_in_alignment < bitsize)
1037 /* out of bits; bump up to next 'word'. */
1038 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1039 rli->bitpos = size_binop (PLUS_EXPR,
1041 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1042 rli->prev_field = field;
1043 rli->remaining_in_alignment = TREE_INT_CST_LOW (type_size);
1045 rli->remaining_in_alignment -= bitsize;
1049 /* End of a run: if leaving a run of bitfields of the same type
1050 size, we have to "use up" the rest of the bits of the type
1053 Compute the new position as the sum of the size for the prior
1054 type and where we first started working on that type.
1055 Note: since the beginning of the field was aligned then
1056 of course the end will be too. No round needed. */
1058 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1060 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1061 rli->bitpos = size_binop (PLUS_EXPR,
1063 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1067 /* We "use up" size zero fields; the code below should behave
1068 as if the prior field was not a bitfield. */
1072 /* Cause a new bitfield to be captured, either this time (if
1073 currently a bitfield) or next time we see one. */
1074 if (!DECL_BIT_FIELD_TYPE(field)
1075 || integer_zerop (DECL_SIZE (field)))
1077 rli->prev_field = NULL;
1080 normalize_rli (rli);
1083 /* If we're starting a new run of same size type bitfields
1084 (or a run of non-bitfields), set up the "first of the run"
1087 That is, if the current field is not a bitfield, or if there
1088 was a prior bitfield the type sizes differ, or if there wasn't
1089 a prior bitfield the size of the current field is nonzero.
1091 Note: we must be sure to test ONLY the type size if there was
1092 a prior bitfield and ONLY for the current field being zero if
1095 if (!DECL_BIT_FIELD_TYPE (field)
1096 || ( prev_saved != NULL
1097 ? !simple_cst_equal (TYPE_SIZE (type),
1098 TYPE_SIZE (TREE_TYPE (prev_saved)))
1099 : !integer_zerop (DECL_SIZE (field)) ))
1101 unsigned int type_align = 8; /* Never below 8 for compatability */
1103 /* (When not a bitfield), we could be seeing a flex array (with
1104 no DECL_SIZE). Since we won't be using remaining_in_alignment
1105 until we see a bitfield (and come by here again) we just skip
1108 if (DECL_SIZE (field) != NULL)
1109 rli->remaining_in_alignment
1110 = TREE_INT_CST_LOW (TYPE_SIZE(TREE_TYPE(field)))
1111 - TREE_INT_CST_LOW (DECL_SIZE (field));
1113 /* Now align (conventionally) for the new type. */
1114 if (!DECL_PACKED(field))
1115 type_align = MAX(TYPE_ALIGN (type), type_align);
1118 && DECL_BIT_FIELD_TYPE (prev_saved)
1119 /* If the previous bit-field is zero-sized, we've already
1120 accounted for its alignment needs (or ignored it, if
1121 appropriate) while placing it. */
1122 && ! integer_zerop (DECL_SIZE (prev_saved)))
1123 type_align = MAX (type_align,
1124 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1126 if (maximum_field_alignment != 0)
1127 type_align = MIN (type_align, maximum_field_alignment);
1129 rli->bitpos = round_up (rli->bitpos, type_align);
1130 /* If we really aligned, don't allow subsequent bitfields
1132 rli->prev_field = NULL;
1136 /* Offset so far becomes the position of this field after normalizing. */
1137 normalize_rli (rli);
1138 DECL_FIELD_OFFSET (field) = rli->offset;
1139 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1140 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1142 /* If this field ended up more aligned than we thought it would be (we
1143 approximate this by seeing if its position changed), lay out the field
1144 again; perhaps we can use an integral mode for it now. */
1145 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1146 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1147 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1148 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1149 actual_align = BIGGEST_ALIGNMENT;
1150 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1151 actual_align = (BITS_PER_UNIT
1152 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1153 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1155 actual_align = DECL_OFFSET_ALIGN (field);
1157 if (known_align != actual_align)
1158 layout_decl (field, actual_align);
1160 /* Only the MS bitfields use this. */
1161 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1162 rli->prev_field = field;
1164 /* Now add size of this field to the size of the record. If the size is
1165 not constant, treat the field as being a multiple of bytes and just
1166 adjust the offset, resetting the bit position. Otherwise, apportion the
1167 size amongst the bit position and offset. First handle the case of an
1168 unspecified size, which can happen when we have an invalid nested struct
1169 definition, such as struct j { struct j { int i; } }. The error message
1170 is printed in finish_struct. */
1171 if (DECL_SIZE (field) == 0)
1173 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1174 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1177 = size_binop (PLUS_EXPR, rli->offset,
1179 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1180 bitsize_unit_node)));
1182 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1183 rli->bitpos = bitsize_zero_node;
1184 rli->offset_align = MIN (rli->offset_align, DECL_ALIGN (field));
1188 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1189 normalize_rli (rli);
1193 /* Assuming that all the fields have been laid out, this function uses
1194 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1195 inidicated by RLI. */
1198 finalize_record_size (rli)
1199 record_layout_info rli;
1201 tree unpadded_size, unpadded_size_unit;
1203 /* Now we want just byte and bit offsets, so set the offset alignment
1204 to be a byte and then normalize. */
1205 rli->offset_align = BITS_PER_UNIT;
1206 normalize_rli (rli);
1208 /* Determine the desired alignment. */
1209 #ifdef ROUND_TYPE_ALIGN
1210 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1213 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1216 /* Compute the size so far. Be sure to allow for extra bits in the
1217 size in bytes. We have guaranteed above that it will be no more
1218 than a single byte. */
1219 unpadded_size = rli_size_so_far (rli);
1220 unpadded_size_unit = rli_size_unit_so_far (rli);
1221 if (! integer_zerop (rli->bitpos))
1223 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1225 /* Record the un-rounded size in the binfo node. But first we check
1226 the size of TYPE_BINFO to make sure that BINFO_SIZE is available. */
1227 if (TYPE_BINFO (rli->t) && TREE_VEC_LENGTH (TYPE_BINFO (rli->t)) > 6)
1229 TYPE_BINFO_SIZE (rli->t) = unpadded_size;
1230 TYPE_BINFO_SIZE_UNIT (rli->t) = unpadded_size_unit;
1233 /* Round the size up to be a multiple of the required alignment */
1234 #ifdef ROUND_TYPE_SIZE
1235 TYPE_SIZE (rli->t) = ROUND_TYPE_SIZE (rli->t, unpadded_size,
1236 TYPE_ALIGN (rli->t));
1237 TYPE_SIZE_UNIT (rli->t)
1238 = ROUND_TYPE_SIZE_UNIT (rli->t, unpadded_size_unit,
1239 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1241 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1242 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1243 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1246 if (warn_padded && TREE_CONSTANT (unpadded_size)
1247 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1248 warning ("padding struct size to alignment boundary");
1250 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1251 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1252 && TREE_CONSTANT (unpadded_size))
1256 #ifdef ROUND_TYPE_ALIGN
1258 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1260 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1263 #ifdef ROUND_TYPE_SIZE
1264 unpacked_size = ROUND_TYPE_SIZE (rli->t, TYPE_SIZE (rli->t),
1265 rli->unpacked_align);
1267 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1270 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1272 TYPE_PACKED (rli->t) = 0;
1274 if (TYPE_NAME (rli->t))
1278 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1279 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1281 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1283 if (STRICT_ALIGNMENT)
1284 warning ("packed attribute causes inefficient alignment for `%s'", name);
1286 warning ("packed attribute is unnecessary for `%s'", name);
1290 if (STRICT_ALIGNMENT)
1291 warning ("packed attribute causes inefficient alignment");
1293 warning ("packed attribute is unnecessary");
1299 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1302 compute_record_mode (type)
1306 enum machine_mode mode = VOIDmode;
1308 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1309 However, if possible, we use a mode that fits in a register
1310 instead, in order to allow for better optimization down the
1312 TYPE_MODE (type) = BLKmode;
1314 if (! host_integerp (TYPE_SIZE (type), 1))
1317 /* A record which has any BLKmode members must itself be
1318 BLKmode; it can't go in a register. Unless the member is
1319 BLKmode only because it isn't aligned. */
1320 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1322 unsigned HOST_WIDE_INT bitpos;
1324 if (TREE_CODE (field) != FIELD_DECL)
1327 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1328 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1329 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
1330 || ! host_integerp (bit_position (field), 1)
1331 || DECL_SIZE (field) == 0
1332 || ! host_integerp (DECL_SIZE (field), 1))
1335 bitpos = int_bit_position (field);
1337 /* Must be BLKmode if any field crosses a word boundary,
1338 since extract_bit_field can't handle that in registers. */
1339 if (bitpos / BITS_PER_WORD
1340 != ((tree_low_cst (DECL_SIZE (field), 1) + bitpos - 1)
1342 /* But there is no problem if the field is entire words. */
1343 && tree_low_cst (DECL_SIZE (field), 1) % BITS_PER_WORD != 0)
1346 /* If this field is the whole struct, remember its mode so
1347 that, say, we can put a double in a class into a DF
1348 register instead of forcing it to live in the stack. */
1349 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1350 mode = DECL_MODE (field);
1352 #ifdef MEMBER_TYPE_FORCES_BLK
1353 /* With some targets, eg. c4x, it is sub-optimal
1354 to access an aligned BLKmode structure as a scalar. */
1356 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1358 #endif /* MEMBER_TYPE_FORCES_BLK */
1361 /* If we only have one real field; use its mode. This only applies to
1362 RECORD_TYPE. This does not apply to unions. */
1363 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1364 TYPE_MODE (type) = mode;
1366 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1368 /* If structure's known alignment is less than what the scalar
1369 mode would need, and it matters, then stick with BLKmode. */
1370 if (TYPE_MODE (type) != BLKmode
1372 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1373 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1375 /* If this is the only reason this type is BLKmode, then
1376 don't force containing types to be BLKmode. */
1377 TYPE_NO_FORCE_BLK (type) = 1;
1378 TYPE_MODE (type) = BLKmode;
1382 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1386 finalize_type_size (type)
1389 /* Normally, use the alignment corresponding to the mode chosen.
1390 However, where strict alignment is not required, avoid
1391 over-aligning structures, since most compilers do not do this
1394 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1395 && (STRICT_ALIGNMENT
1396 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1397 && TREE_CODE (type) != QUAL_UNION_TYPE
1398 && TREE_CODE (type) != ARRAY_TYPE)))
1400 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1401 TYPE_USER_ALIGN (type) = 0;
1404 /* Do machine-dependent extra alignment. */
1405 #ifdef ROUND_TYPE_ALIGN
1407 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1410 /* If we failed to find a simple way to calculate the unit size
1411 of the type, find it by division. */
1412 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1413 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1414 result will fit in sizetype. We will get more efficient code using
1415 sizetype, so we force a conversion. */
1416 TYPE_SIZE_UNIT (type)
1417 = convert (sizetype,
1418 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1419 bitsize_unit_node));
1421 if (TYPE_SIZE (type) != 0)
1423 #ifdef ROUND_TYPE_SIZE
1425 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1426 TYPE_SIZE_UNIT (type)
1427 = ROUND_TYPE_SIZE_UNIT (type, TYPE_SIZE_UNIT (type),
1428 TYPE_ALIGN (type) / BITS_PER_UNIT);
1430 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1431 TYPE_SIZE_UNIT (type)
1432 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1436 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1437 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1438 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1439 if (TYPE_SIZE_UNIT (type) != 0
1440 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1441 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1443 /* Also layout any other variants of the type. */
1444 if (TYPE_NEXT_VARIANT (type)
1445 || type != TYPE_MAIN_VARIANT (type))
1448 /* Record layout info of this variant. */
1449 tree size = TYPE_SIZE (type);
1450 tree size_unit = TYPE_SIZE_UNIT (type);
1451 unsigned int align = TYPE_ALIGN (type);
1452 unsigned int user_align = TYPE_USER_ALIGN (type);
1453 enum machine_mode mode = TYPE_MODE (type);
1455 /* Copy it into all variants. */
1456 for (variant = TYPE_MAIN_VARIANT (type);
1458 variant = TYPE_NEXT_VARIANT (variant))
1460 TYPE_SIZE (variant) = size;
1461 TYPE_SIZE_UNIT (variant) = size_unit;
1462 TYPE_ALIGN (variant) = align;
1463 TYPE_USER_ALIGN (variant) = user_align;
1464 TYPE_MODE (variant) = mode;
1469 /* Do all of the work required to layout the type indicated by RLI,
1470 once the fields have been laid out. This function will call `free'
1471 for RLI, unless FREE_P is false. Passing a value other than false
1472 for FREE_P is bad practice; this option only exists to support the
1476 finish_record_layout (rli, free_p)
1477 record_layout_info rli;
1480 /* Compute the final size. */
1481 finalize_record_size (rli);
1483 /* Compute the TYPE_MODE for the record. */
1484 compute_record_mode (rli->t);
1486 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1487 finalize_type_size (rli->t);
1489 /* Lay out any static members. This is done now because their type
1490 may use the record's type. */
1491 while (rli->pending_statics)
1493 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1494 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1503 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1504 NAME, its fields are chained in reverse on FIELDS.
1506 If ALIGN_TYPE is non-null, it is given the same alignment as
1510 finish_builtin_struct (type, name, fields, align_type)
1518 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1520 DECL_FIELD_CONTEXT (fields) = type;
1521 next = TREE_CHAIN (fields);
1522 TREE_CHAIN (fields) = tail;
1524 TYPE_FIELDS (type) = tail;
1528 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1529 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1533 #if 0 /* not yet, should get fixed properly later */
1534 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1536 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1538 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1539 layout_decl (TYPE_NAME (type), 0);
1542 /* Calculate the mode, size, and alignment for TYPE.
1543 For an array type, calculate the element separation as well.
1544 Record TYPE on the chain of permanent or temporary types
1545 so that dbxout will find out about it.
1547 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1548 layout_type does nothing on such a type.
1550 If the type is incomplete, its TYPE_SIZE remains zero. */
1559 /* Do nothing if type has been laid out before. */
1560 if (TYPE_SIZE (type))
1563 switch (TREE_CODE (type))
1566 /* This kind of type is the responsibility
1567 of the language-specific code. */
1570 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1571 if (TYPE_PRECISION (type) == 0)
1572 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1574 /* ... fall through ... */
1579 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1580 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1581 TREE_UNSIGNED (type) = 1;
1583 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1585 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1586 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1590 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1591 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1592 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1596 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1598 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1599 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1600 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1602 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1603 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1610 subtype = TREE_TYPE (type);
1611 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1612 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1613 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1618 /* This is an incomplete type and so doesn't have a size. */
1619 TYPE_ALIGN (type) = 1;
1620 TYPE_USER_ALIGN (type) = 0;
1621 TYPE_MODE (type) = VOIDmode;
1625 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1626 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1627 /* A pointer might be MODE_PARTIAL_INT,
1628 but ptrdiff_t must be integral. */
1629 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1634 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1635 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1636 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1640 case REFERENCE_TYPE:
1643 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1644 && reference_types_internal)
1645 ? Pmode : TYPE_MODE (type));
1647 int nbits = GET_MODE_BITSIZE (mode);
1649 TYPE_SIZE (type) = bitsize_int (nbits);
1650 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1651 TREE_UNSIGNED (type) = 1;
1652 TYPE_PRECISION (type) = nbits;
1658 tree index = TYPE_DOMAIN (type);
1659 tree element = TREE_TYPE (type);
1661 build_pointer_type (element);
1663 /* We need to know both bounds in order to compute the size. */
1664 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1665 && TYPE_SIZE (element))
1667 tree ub = TYPE_MAX_VALUE (index);
1668 tree lb = TYPE_MIN_VALUE (index);
1672 /* The initial subtraction should happen in the original type so
1673 that (possible) negative values are handled appropriately. */
1674 length = size_binop (PLUS_EXPR, size_one_node,
1676 fold (build (MINUS_EXPR,
1680 /* Special handling for arrays of bits (for Chill). */
1681 element_size = TYPE_SIZE (element);
1682 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1683 && (integer_zerop (TYPE_MAX_VALUE (element))
1684 || integer_onep (TYPE_MAX_VALUE (element)))
1685 && host_integerp (TYPE_MIN_VALUE (element), 1))
1687 HOST_WIDE_INT maxvalue
1688 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1689 HOST_WIDE_INT minvalue
1690 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1692 if (maxvalue - minvalue == 1
1693 && (maxvalue == 1 || maxvalue == 0))
1694 element_size = integer_one_node;
1697 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1698 convert (bitsizetype, length));
1700 /* If we know the size of the element, calculate the total
1701 size directly, rather than do some division thing below.
1702 This optimization helps Fortran assumed-size arrays
1703 (where the size of the array is determined at runtime)
1705 Note that we can't do this in the case where the size of
1706 the elements is one bit since TYPE_SIZE_UNIT cannot be
1707 set correctly in that case. */
1708 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1709 TYPE_SIZE_UNIT (type)
1710 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1713 /* Now round the alignment and size,
1714 using machine-dependent criteria if any. */
1716 #ifdef ROUND_TYPE_ALIGN
1718 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1720 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1722 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1724 #ifdef ROUND_TYPE_SIZE
1725 if (TYPE_SIZE (type) != 0)
1728 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1730 /* If the rounding changed the size of the type, remove any
1731 pre-calculated TYPE_SIZE_UNIT. */
1732 if (simple_cst_equal (TYPE_SIZE (type), tmp) != 1)
1733 TYPE_SIZE_UNIT (type) = NULL;
1735 TYPE_SIZE (type) = tmp;
1739 TYPE_MODE (type) = BLKmode;
1740 if (TYPE_SIZE (type) != 0
1741 #ifdef MEMBER_TYPE_FORCES_BLK
1742 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1744 /* BLKmode elements force BLKmode aggregate;
1745 else extract/store fields may lose. */
1746 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1747 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1749 /* One-element arrays get the component type's mode. */
1750 if (simple_cst_equal (TYPE_SIZE (type),
1751 TYPE_SIZE (TREE_TYPE (type))))
1752 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1755 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1757 if (TYPE_MODE (type) != BLKmode
1758 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1759 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1760 && TYPE_MODE (type) != BLKmode)
1762 TYPE_NO_FORCE_BLK (type) = 1;
1763 TYPE_MODE (type) = BLKmode;
1771 case QUAL_UNION_TYPE:
1774 record_layout_info rli;
1776 /* Initialize the layout information. */
1777 rli = start_record_layout (type);
1779 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1780 in the reverse order in building the COND_EXPR that denotes
1781 its size. We reverse them again later. */
1782 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1783 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1785 /* Place all the fields. */
1786 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1787 place_field (rli, field);
1789 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1790 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1792 if (lang_adjust_rli)
1793 (*lang_adjust_rli) (rli);
1795 /* Finish laying out the record. */
1796 finish_record_layout (rli, /*free_p=*/true);
1800 case SET_TYPE: /* Used by Chill and Pascal. */
1801 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1802 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1806 #ifndef SET_WORD_SIZE
1807 #define SET_WORD_SIZE BITS_PER_WORD
1809 unsigned int alignment
1810 = set_alignment ? set_alignment : SET_WORD_SIZE;
1812 = (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
1813 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1);
1815 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1817 if (rounded_size > (int) alignment)
1818 TYPE_MODE (type) = BLKmode;
1820 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1822 TYPE_SIZE (type) = bitsize_int (rounded_size);
1823 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1824 TYPE_ALIGN (type) = alignment;
1825 TYPE_USER_ALIGN (type) = 0;
1826 TYPE_PRECISION (type) = size_in_bits;
1831 /* The size may vary in different languages, so the language front end
1832 should fill in the size. */
1833 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1834 TYPE_USER_ALIGN (type) = 0;
1835 TYPE_MODE (type) = BLKmode;
1842 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1843 records and unions, finish_record_layout already called this
1845 if (TREE_CODE (type) != RECORD_TYPE
1846 && TREE_CODE (type) != UNION_TYPE
1847 && TREE_CODE (type) != QUAL_UNION_TYPE)
1848 finalize_type_size (type);
1850 /* If this type is created before sizetype has been permanently set,
1851 record it so set_sizetype can fix it up. */
1853 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1855 /* If an alias set has been set for this aggregate when it was incomplete,
1856 force it into alias set 0.
1857 This is too conservative, but we cannot call record_component_aliases
1858 here because some frontends still change the aggregates after
1860 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1861 TYPE_ALIAS_SET (type) = 0;
1864 /* Create and return a type for signed integers of PRECISION bits. */
1867 make_signed_type (precision)
1870 tree type = make_node (INTEGER_TYPE);
1872 TYPE_PRECISION (type) = precision;
1874 fixup_signed_type (type);
1878 /* Create and return a type for unsigned integers of PRECISION bits. */
1881 make_unsigned_type (precision)
1884 tree type = make_node (INTEGER_TYPE);
1886 TYPE_PRECISION (type) = precision;
1888 fixup_unsigned_type (type);
1892 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1893 value to enable integer types to be created. */
1896 initialize_sizetypes ()
1898 tree t = make_node (INTEGER_TYPE);
1900 /* Set this so we do something reasonable for the build_int_2 calls
1902 integer_type_node = t;
1904 TYPE_MODE (t) = SImode;
1905 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1906 TYPE_USER_ALIGN (t) = 0;
1907 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1908 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1909 TREE_UNSIGNED (t) = 1;
1910 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1911 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1912 TYPE_IS_SIZETYPE (t) = 1;
1914 /* 1000 avoids problems with possible overflow and is certainly
1915 larger than any size value we'd want to be storing. */
1916 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1918 /* These two must be different nodes because of the caching done in
1921 bitsizetype = copy_node (t);
1922 integer_type_node = 0;
1925 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1926 Also update the type of any standard type's sizes made so far. */
1932 int oprecision = TYPE_PRECISION (type);
1933 /* The *bitsizetype types use a precision that avoids overflows when
1934 calculating signed sizes / offsets in bits. However, when
1935 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1937 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1938 2 * HOST_BITS_PER_WIDE_INT);
1945 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1946 sizetype = copy_node (type);
1947 TYPE_DOMAIN (sizetype) = type;
1948 TYPE_IS_SIZETYPE (sizetype) = 1;
1949 bitsizetype = make_node (INTEGER_TYPE);
1950 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1951 TYPE_PRECISION (bitsizetype) = precision;
1952 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1954 if (TREE_UNSIGNED (type))
1955 fixup_unsigned_type (bitsizetype);
1957 fixup_signed_type (bitsizetype);
1959 layout_type (bitsizetype);
1961 if (TREE_UNSIGNED (type))
1963 usizetype = sizetype;
1964 ubitsizetype = bitsizetype;
1965 ssizetype = copy_node (make_signed_type (oprecision));
1966 sbitsizetype = copy_node (make_signed_type (precision));
1970 ssizetype = sizetype;
1971 sbitsizetype = bitsizetype;
1972 usizetype = copy_node (make_unsigned_type (oprecision));
1973 ubitsizetype = copy_node (make_unsigned_type (precision));
1976 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1978 /* Show is a sizetype, is a main type, and has no pointers to it. */
1979 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1981 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1982 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1983 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1984 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1985 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1988 /* Go down each of the types we already made and set the proper type
1989 for the sizes in them. */
1990 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1992 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE)
1995 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1996 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1999 early_type_list = 0;
2003 /* Set the extreme values of TYPE based on its precision in bits,
2004 then lay it out. Used when make_signed_type won't do
2005 because the tree code is not INTEGER_TYPE.
2006 E.g. for Pascal, when the -fsigned-char option is given. */
2009 fixup_signed_type (type)
2012 int precision = TYPE_PRECISION (type);
2014 /* We can not represent properly constants greater then
2015 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2016 as they are used by i386 vector extensions and friends. */
2017 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2018 precision = HOST_BITS_PER_WIDE_INT * 2;
2020 TYPE_MIN_VALUE (type)
2021 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2022 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
2023 (((HOST_WIDE_INT) (-1)
2024 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2025 ? precision - HOST_BITS_PER_WIDE_INT - 1
2027 TYPE_MAX_VALUE (type)
2028 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2029 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2030 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2031 ? (((HOST_WIDE_INT) 1
2032 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2035 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2036 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2038 /* Lay out the type: set its alignment, size, etc. */
2042 /* Set the extreme values of TYPE based on its precision in bits,
2043 then lay it out. This is used both in `make_unsigned_type'
2044 and for enumeral types. */
2047 fixup_unsigned_type (type)
2050 int precision = TYPE_PRECISION (type);
2052 /* We can not represent properly constants greater then
2053 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2054 as they are used by i386 vector extensions and friends. */
2055 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2056 precision = HOST_BITS_PER_WIDE_INT * 2;
2058 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
2059 TYPE_MAX_VALUE (type)
2060 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
2061 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
2062 precision - HOST_BITS_PER_WIDE_INT > 0
2063 ? ((unsigned HOST_WIDE_INT) ~0
2064 >> (HOST_BITS_PER_WIDE_INT
2065 - (precision - HOST_BITS_PER_WIDE_INT)))
2067 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2068 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2070 /* Lay out the type: set its alignment, size, etc. */
2074 /* Find the best machine mode to use when referencing a bit field of length
2075 BITSIZE bits starting at BITPOS.
2077 The underlying object is known to be aligned to a boundary of ALIGN bits.
2078 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2079 larger than LARGEST_MODE (usually SImode).
2081 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2082 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2083 mode meeting these conditions.
2085 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2086 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2087 all the conditions. */
2090 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
2091 int bitsize, bitpos;
2093 enum machine_mode largest_mode;
2096 enum machine_mode mode;
2097 unsigned int unit = 0;
2099 /* Find the narrowest integer mode that contains the bit field. */
2100 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2101 mode = GET_MODE_WIDER_MODE (mode))
2103 unit = GET_MODE_BITSIZE (mode);
2104 if ((bitpos % unit) + bitsize <= unit)
2108 if (mode == VOIDmode
2109 /* It is tempting to omit the following line
2110 if STRICT_ALIGNMENT is true.
2111 But that is incorrect, since if the bitfield uses part of 3 bytes
2112 and we use a 4-byte mode, we could get a spurious segv
2113 if the extra 4th byte is past the end of memory.
2114 (Though at least one Unix compiler ignores this problem:
2115 that on the Sequent 386 machine. */
2116 || MIN (unit, BIGGEST_ALIGNMENT) > align
2117 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2120 if (SLOW_BYTE_ACCESS && ! volatilep)
2122 enum machine_mode wide_mode = VOIDmode, tmode;
2124 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2125 tmode = GET_MODE_WIDER_MODE (tmode))
2127 unit = GET_MODE_BITSIZE (tmode);
2128 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2129 && unit <= BITS_PER_WORD
2130 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2131 && (largest_mode == VOIDmode
2132 || unit <= GET_MODE_BITSIZE (largest_mode)))
2136 if (wide_mode != VOIDmode)
2143 #include "gt-stor-layout.h"