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))
725 desired_align = TYPE_ALIGN (type);
727 /* A named bit field of declared type `int'
728 forces the entire structure to have `int' alignment. */
729 if (DECL_NAME (field) != 0)
731 unsigned int type_align = TYPE_ALIGN (type);
733 #ifdef ADJUST_FIELD_ALIGN
734 if (! TYPE_USER_ALIGN (type))
735 type_align = ADJUST_FIELD_ALIGN (field, type_align);
738 if (maximum_field_alignment != 0)
739 type_align = MIN (type_align, maximum_field_alignment);
740 else if (DECL_PACKED (field))
741 type_align = MIN (type_align, BITS_PER_UNIT);
743 rli->record_align = MAX (rli->record_align, type_align);
744 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
746 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
747 user_align |= TYPE_USER_ALIGN (type);
753 rli->record_align = MAX (rli->record_align, desired_align);
754 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
755 rli->unpadded_align = MAX (rli->unpadded_align, DECL_ALIGN (field));
758 TYPE_USER_ALIGN (rli->t) |= user_align;
760 return desired_align;
763 /* Called from place_field to handle unions. */
766 place_union_field (rli, field)
767 record_layout_info rli;
770 update_alignment_for_field (rli, field, /*known_align=*/0);
772 DECL_FIELD_OFFSET (field) = size_zero_node;
773 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
774 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
776 /* We assume the union's size will be a multiple of a byte so we don't
777 bother with BITPOS. */
778 if (TREE_CODE (rli->t) == UNION_TYPE)
779 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
780 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
781 rli->offset = fold (build (COND_EXPR, sizetype,
782 DECL_QUALIFIER (field),
783 DECL_SIZE_UNIT (field), rli->offset));
786 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
787 at BYTE_OFFSET / BIT_OFFSET. Return non-zero if the field would span more
788 units of alignment than the underlying TYPE. */
790 excess_unit_span (byte_offset, bit_offset, size, align, type)
791 HOST_WIDE_INT byte_offset, bit_offset, size, align;
794 /* Note that the calculation of OFFSET might overflow; we calculate it so
795 that we still get the right result as long as ALIGN is a power of two. */
796 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
798 offset = offset % align;
799 return ((offset + size + align - 1) / align
800 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
804 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
805 is a FIELD_DECL to be added after those fields already present in
806 T. (FIELD is not actually added to the TYPE_FIELDS list here;
807 callers that desire that behavior must manually perform that step.) */
810 place_field (rli, field)
811 record_layout_info rli;
814 /* The alignment required for FIELD. */
815 unsigned int desired_align;
816 /* The alignment FIELD would have if we just dropped it into the
817 record as it presently stands. */
818 unsigned int known_align;
819 unsigned int actual_align;
820 /* The type of this field. */
821 tree type = TREE_TYPE (field);
823 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
826 /* If FIELD is static, then treat it like a separate variable, not
827 really like a structure field. If it is a FUNCTION_DECL, it's a
828 method. In both cases, all we do is lay out the decl, and we do
829 it *after* the record is laid out. */
830 if (TREE_CODE (field) == VAR_DECL)
832 rli->pending_statics = tree_cons (NULL_TREE, field,
833 rli->pending_statics);
837 /* Enumerators and enum types which are local to this class need not
838 be laid out. Likewise for initialized constant fields. */
839 else if (TREE_CODE (field) != FIELD_DECL)
842 /* Unions are laid out very differently than records, so split
843 that code off to another function. */
844 else if (TREE_CODE (rli->t) != RECORD_TYPE)
846 place_union_field (rli, field);
850 /* Work out the known alignment so far. Note that A & (-A) is the
851 value of the least-significant bit in A that is one. */
852 if (! integer_zerop (rli->bitpos))
853 known_align = (tree_low_cst (rli->bitpos, 1)
854 & - tree_low_cst (rli->bitpos, 1));
855 else if (integer_zerop (rli->offset))
856 known_align = BIGGEST_ALIGNMENT;
857 else if (host_integerp (rli->offset, 1))
858 known_align = (BITS_PER_UNIT
859 * (tree_low_cst (rli->offset, 1)
860 & - tree_low_cst (rli->offset, 1)));
862 known_align = rli->offset_align;
864 desired_align = update_alignment_for_field (rli, field, known_align);
866 if (warn_packed && DECL_PACKED (field))
868 if (known_align > TYPE_ALIGN (type))
870 if (TYPE_ALIGN (type) > desired_align)
872 if (STRICT_ALIGNMENT)
873 warning_with_decl (field, "packed attribute causes inefficient alignment for `%s'");
875 warning_with_decl (field, "packed attribute is unnecessary for `%s'");
879 rli->packed_maybe_necessary = 1;
882 /* Does this field automatically have alignment it needs by virtue
883 of the fields that precede it and the record's own alignment? */
884 if (known_align < desired_align)
886 /* No, we need to skip space before this field.
887 Bump the cumulative size to multiple of field alignment. */
890 warning_with_decl (field, "padding struct to align `%s'");
892 /* If the alignment is still within offset_align, just align
894 if (desired_align < rli->offset_align)
895 rli->bitpos = round_up (rli->bitpos, desired_align);
898 /* First adjust OFFSET by the partial bits, then align. */
900 = size_binop (PLUS_EXPR, rli->offset,
902 size_binop (CEIL_DIV_EXPR, rli->bitpos,
903 bitsize_unit_node)));
904 rli->bitpos = bitsize_zero_node;
906 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
909 if (! TREE_CONSTANT (rli->offset))
910 rli->offset_align = desired_align;
914 /* Handle compatibility with PCC. Note that if the record has any
915 variable-sized fields, we need not worry about compatibility. */
916 #ifdef PCC_BITFIELD_TYPE_MATTERS
917 if (PCC_BITFIELD_TYPE_MATTERS
918 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
919 && TREE_CODE (field) == FIELD_DECL
920 && type != error_mark_node
921 && DECL_BIT_FIELD (field)
922 && ! DECL_PACKED (field)
923 && maximum_field_alignment == 0
924 && ! integer_zerop (DECL_SIZE (field))
925 && host_integerp (DECL_SIZE (field), 1)
926 && host_integerp (rli->offset, 1)
927 && host_integerp (TYPE_SIZE (type), 1))
929 unsigned int type_align = TYPE_ALIGN (type);
930 tree dsize = DECL_SIZE (field);
931 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
932 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
933 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
935 #ifdef ADJUST_FIELD_ALIGN
936 if (! TYPE_USER_ALIGN (type))
937 type_align = ADJUST_FIELD_ALIGN (field, type_align);
940 /* A bit field may not span more units of alignment of its type
941 than its type itself. Advance to next boundary if necessary. */
942 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
943 rli->bitpos = round_up (rli->bitpos, type_align);
945 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
949 #ifdef BITFIELD_NBYTES_LIMITED
950 if (BITFIELD_NBYTES_LIMITED
951 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
952 && TREE_CODE (field) == FIELD_DECL
953 && type != error_mark_node
954 && DECL_BIT_FIELD_TYPE (field)
955 && ! DECL_PACKED (field)
956 && ! integer_zerop (DECL_SIZE (field))
957 && host_integerp (DECL_SIZE (field), 1)
958 && host_integerp (rli->offset, 1)
959 && host_integerp (TYPE_SIZE (type), 1))
961 unsigned int type_align = TYPE_ALIGN (type);
962 tree dsize = DECL_SIZE (field);
963 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
964 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
965 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
967 #ifdef ADJUST_FIELD_ALIGN
968 if (! TYPE_USER_ALIGN (type))
969 type_align = ADJUST_FIELD_ALIGN (field, type_align);
972 if (maximum_field_alignment != 0)
973 type_align = MIN (type_align, maximum_field_alignment);
974 /* ??? This test is opposite the test in the containing if
975 statement, so this code is unreachable currently. */
976 else if (DECL_PACKED (field))
977 type_align = MIN (type_align, BITS_PER_UNIT);
979 /* A bit field may not span the unit of alignment of its type.
980 Advance to next boundary if necessary. */
981 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
982 rli->bitpos = round_up (rli->bitpos, type_align);
984 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
988 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
990 When a bit field is inserted into a packed record, the whole
991 size of the underlying type is used by one or more same-size
992 adjacent bitfields. (That is, if its long:3, 32 bits is
993 used in the record, and any additional adjacent long bitfields are
994 packed into the same chunk of 32 bits. However, if the size
995 changes, a new field of that size is allocated.) In an unpacked
996 record, this is the same as using alignment, but not eqivalent
999 Note: for compatability, we use the type size, not the type alignment
1000 to determine alignment, since that matches the documentation */
1002 if ((* targetm.ms_bitfield_layout_p) (rli->t)
1003 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1004 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1006 /* At this point, either the prior or current are bitfields,
1007 (possibly both), and we're dealing with MS packing. */
1008 tree prev_saved = rli->prev_field;
1010 /* Is the prior field a bitfield? If so, handle "runs" of same
1011 type size fields. */
1012 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1014 /* If both are bitfields, nonzero, and the same size, this is
1015 the middle of a run. Zero declared size fields are special
1016 and handled as "end of run". (Note: it's nonzero declared
1017 size, but equal type sizes!) (Since we know that both
1018 the current and previous fields are bitfields by the
1019 time we check it, DECL_SIZE must be present for both.) */
1020 if (DECL_BIT_FIELD_TYPE (field)
1021 && !integer_zerop (DECL_SIZE (field))
1022 && !integer_zerop (DECL_SIZE (rli->prev_field))
1023 && simple_cst_equal (TYPE_SIZE (type),
1024 TYPE_SIZE (TREE_TYPE (rli->prev_field))) )
1026 /* We're in the middle of a run of equal type size fields; make
1027 sure we realign if we run out of bits. (Not decl size,
1029 int bitsize = TREE_INT_CST_LOW (DECL_SIZE (field));
1030 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1032 if (rli->remaining_in_alignment < bitsize)
1034 /* out of bits; bump up to next 'word'. */
1035 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1036 rli->bitpos = size_binop (PLUS_EXPR,
1038 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1039 rli->prev_field = field;
1040 rli->remaining_in_alignment = TREE_INT_CST_LOW (type_size);
1042 rli->remaining_in_alignment -= bitsize;
1046 /* End of a run: if leaving a run of bitfields of the same type
1047 size, we have to "use up" the rest of the bits of the type
1050 Compute the new position as the sum of the size for the prior
1051 type and where we first started working on that type.
1052 Note: since the beginning of the field was aligned then
1053 of course the end will be too. No round needed. */
1055 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1057 tree type_size = TYPE_SIZE(TREE_TYPE(rli->prev_field));
1058 rli->bitpos = size_binop (PLUS_EXPR,
1060 DECL_FIELD_BIT_OFFSET(rli->prev_field));
1064 /* We "use up" size zero fields; the code below should behave
1065 as if the prior field was not a bitfield. */
1069 /* Cause a new bitfield to be captured, either this time (if
1070 currently a bitfield) or next time we see one. */
1071 if (!DECL_BIT_FIELD_TYPE(field)
1072 || integer_zerop (DECL_SIZE (field)))
1074 rli->prev_field = NULL;
1077 normalize_rli (rli);
1080 /* If we're starting a new run of same size type bitfields
1081 (or a run of non-bitfields), set up the "first of the run"
1084 That is, if the current field is not a bitfield, or if there
1085 was a prior bitfield the type sizes differ, or if there wasn't
1086 a prior bitfield the size of the current field is nonzero.
1088 Note: we must be sure to test ONLY the type size if there was
1089 a prior bitfield and ONLY for the current field being zero if
1092 if (!DECL_BIT_FIELD_TYPE (field)
1093 || ( prev_saved != NULL
1094 ? !simple_cst_equal (TYPE_SIZE (type),
1095 TYPE_SIZE (TREE_TYPE (prev_saved)))
1096 : !integer_zerop (DECL_SIZE (field)) ))
1098 unsigned int type_align = 8; /* Never below 8 for compatability */
1100 /* (When not a bitfield), we could be seeing a flex array (with
1101 no DECL_SIZE). Since we won't be using remaining_in_alignment
1102 until we see a bitfield (and come by here again) we just skip
1105 if (DECL_SIZE (field) != NULL)
1106 rli->remaining_in_alignment
1107 = TREE_INT_CST_LOW (TYPE_SIZE(TREE_TYPE(field)))
1108 - TREE_INT_CST_LOW (DECL_SIZE (field));
1110 /* Now align (conventionally) for the new type. */
1111 if (!DECL_PACKED(field))
1112 type_align = MAX(TYPE_ALIGN (type), type_align);
1115 && DECL_BIT_FIELD_TYPE (prev_saved)
1116 /* If the previous bit-field is zero-sized, we've already
1117 accounted for its alignment needs (or ignored it, if
1118 appropriate) while placing it. */
1119 && ! integer_zerop (DECL_SIZE (prev_saved)))
1120 type_align = MAX (type_align,
1121 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1123 if (maximum_field_alignment != 0)
1124 type_align = MIN (type_align, maximum_field_alignment);
1126 rli->bitpos = round_up (rli->bitpos, type_align);
1127 /* If we really aligned, don't allow subsequent bitfields
1129 rli->prev_field = NULL;
1133 /* Offset so far becomes the position of this field after normalizing. */
1134 normalize_rli (rli);
1135 DECL_FIELD_OFFSET (field) = rli->offset;
1136 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1137 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1139 /* If this field ended up more aligned than we thought it would be (we
1140 approximate this by seeing if its position changed), lay out the field
1141 again; perhaps we can use an integral mode for it now. */
1142 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1143 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1144 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1145 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1146 actual_align = BIGGEST_ALIGNMENT;
1147 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1148 actual_align = (BITS_PER_UNIT
1149 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1150 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1152 actual_align = DECL_OFFSET_ALIGN (field);
1154 if (known_align != actual_align)
1155 layout_decl (field, actual_align);
1157 /* Only the MS bitfields use this. */
1158 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1159 rli->prev_field = field;
1161 /* Now add size of this field to the size of the record. If the size is
1162 not constant, treat the field as being a multiple of bytes and just
1163 adjust the offset, resetting the bit position. Otherwise, apportion the
1164 size amongst the bit position and offset. First handle the case of an
1165 unspecified size, which can happen when we have an invalid nested struct
1166 definition, such as struct j { struct j { int i; } }. The error message
1167 is printed in finish_struct. */
1168 if (DECL_SIZE (field) == 0)
1170 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1171 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1174 = size_binop (PLUS_EXPR, rli->offset,
1176 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1177 bitsize_unit_node)));
1179 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1180 rli->bitpos = bitsize_zero_node;
1181 rli->offset_align = MIN (rli->offset_align, DECL_ALIGN (field));
1185 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1186 normalize_rli (rli);
1190 /* Assuming that all the fields have been laid out, this function uses
1191 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1192 inidicated by RLI. */
1195 finalize_record_size (rli)
1196 record_layout_info rli;
1198 tree unpadded_size, unpadded_size_unit;
1200 /* Now we want just byte and bit offsets, so set the offset alignment
1201 to be a byte and then normalize. */
1202 rli->offset_align = BITS_PER_UNIT;
1203 normalize_rli (rli);
1205 /* Determine the desired alignment. */
1206 #ifdef ROUND_TYPE_ALIGN
1207 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1210 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1213 /* Compute the size so far. Be sure to allow for extra bits in the
1214 size in bytes. We have guaranteed above that it will be no more
1215 than a single byte. */
1216 unpadded_size = rli_size_so_far (rli);
1217 unpadded_size_unit = rli_size_unit_so_far (rli);
1218 if (! integer_zerop (rli->bitpos))
1220 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1222 /* Record the un-rounded size in the binfo node. But first we check
1223 the size of TYPE_BINFO to make sure that BINFO_SIZE is available. */
1224 if (TYPE_BINFO (rli->t) && TREE_VEC_LENGTH (TYPE_BINFO (rli->t)) > 6)
1226 TYPE_BINFO_SIZE (rli->t) = unpadded_size;
1227 TYPE_BINFO_SIZE_UNIT (rli->t) = unpadded_size_unit;
1230 /* Round the size up to be a multiple of the required alignment */
1231 #ifdef ROUND_TYPE_SIZE
1232 TYPE_SIZE (rli->t) = ROUND_TYPE_SIZE (rli->t, unpadded_size,
1233 TYPE_ALIGN (rli->t));
1234 TYPE_SIZE_UNIT (rli->t)
1235 = ROUND_TYPE_SIZE_UNIT (rli->t, unpadded_size_unit,
1236 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1238 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1239 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1240 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1243 if (warn_padded && TREE_CONSTANT (unpadded_size)
1244 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1245 warning ("padding struct size to alignment boundary");
1247 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1248 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1249 && TREE_CONSTANT (unpadded_size))
1253 #ifdef ROUND_TYPE_ALIGN
1255 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1257 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1260 #ifdef ROUND_TYPE_SIZE
1261 unpacked_size = ROUND_TYPE_SIZE (rli->t, TYPE_SIZE (rli->t),
1262 rli->unpacked_align);
1264 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1267 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1269 TYPE_PACKED (rli->t) = 0;
1271 if (TYPE_NAME (rli->t))
1275 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1276 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1278 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1280 if (STRICT_ALIGNMENT)
1281 warning ("packed attribute causes inefficient alignment for `%s'", name);
1283 warning ("packed attribute is unnecessary for `%s'", name);
1287 if (STRICT_ALIGNMENT)
1288 warning ("packed attribute causes inefficient alignment");
1290 warning ("packed attribute is unnecessary");
1296 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1299 compute_record_mode (type)
1303 enum machine_mode mode = VOIDmode;
1305 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1306 However, if possible, we use a mode that fits in a register
1307 instead, in order to allow for better optimization down the
1309 TYPE_MODE (type) = BLKmode;
1311 if (! host_integerp (TYPE_SIZE (type), 1))
1314 /* A record which has any BLKmode members must itself be
1315 BLKmode; it can't go in a register. Unless the member is
1316 BLKmode only because it isn't aligned. */
1317 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1319 unsigned HOST_WIDE_INT bitpos;
1321 if (TREE_CODE (field) != FIELD_DECL)
1324 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1325 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1326 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
1327 || ! host_integerp (bit_position (field), 1)
1328 || DECL_SIZE (field) == 0
1329 || ! host_integerp (DECL_SIZE (field), 1))
1332 bitpos = int_bit_position (field);
1334 /* Must be BLKmode if any field crosses a word boundary,
1335 since extract_bit_field can't handle that in registers. */
1336 if (bitpos / BITS_PER_WORD
1337 != ((tree_low_cst (DECL_SIZE (field), 1) + bitpos - 1)
1339 /* But there is no problem if the field is entire words. */
1340 && tree_low_cst (DECL_SIZE (field), 1) % BITS_PER_WORD != 0)
1343 /* If this field is the whole struct, remember its mode so
1344 that, say, we can put a double in a class into a DF
1345 register instead of forcing it to live in the stack. */
1346 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1347 mode = DECL_MODE (field);
1349 #ifdef MEMBER_TYPE_FORCES_BLK
1350 /* With some targets, eg. c4x, it is sub-optimal
1351 to access an aligned BLKmode structure as a scalar. */
1353 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1355 #endif /* MEMBER_TYPE_FORCES_BLK */
1358 /* If we only have one real field; use its mode. This only applies to
1359 RECORD_TYPE. This does not apply to unions. */
1360 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1361 TYPE_MODE (type) = mode;
1363 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1365 /* If structure's known alignment is less than what the scalar
1366 mode would need, and it matters, then stick with BLKmode. */
1367 if (TYPE_MODE (type) != BLKmode
1369 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1370 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1372 /* If this is the only reason this type is BLKmode, then
1373 don't force containing types to be BLKmode. */
1374 TYPE_NO_FORCE_BLK (type) = 1;
1375 TYPE_MODE (type) = BLKmode;
1379 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1383 finalize_type_size (type)
1386 /* Normally, use the alignment corresponding to the mode chosen.
1387 However, where strict alignment is not required, avoid
1388 over-aligning structures, since most compilers do not do this
1391 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1392 && (STRICT_ALIGNMENT
1393 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1394 && TREE_CODE (type) != QUAL_UNION_TYPE
1395 && TREE_CODE (type) != ARRAY_TYPE)))
1397 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1398 TYPE_USER_ALIGN (type) = 0;
1401 /* Do machine-dependent extra alignment. */
1402 #ifdef ROUND_TYPE_ALIGN
1404 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1407 /* If we failed to find a simple way to calculate the unit size
1408 of the type, find it by division. */
1409 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1410 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1411 result will fit in sizetype. We will get more efficient code using
1412 sizetype, so we force a conversion. */
1413 TYPE_SIZE_UNIT (type)
1414 = convert (sizetype,
1415 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1416 bitsize_unit_node));
1418 if (TYPE_SIZE (type) != 0)
1420 #ifdef ROUND_TYPE_SIZE
1422 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1423 TYPE_SIZE_UNIT (type)
1424 = ROUND_TYPE_SIZE_UNIT (type, TYPE_SIZE_UNIT (type),
1425 TYPE_ALIGN (type) / BITS_PER_UNIT);
1427 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1428 TYPE_SIZE_UNIT (type)
1429 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1433 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1434 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1435 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1436 if (TYPE_SIZE_UNIT (type) != 0
1437 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1438 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1440 /* Also layout any other variants of the type. */
1441 if (TYPE_NEXT_VARIANT (type)
1442 || type != TYPE_MAIN_VARIANT (type))
1445 /* Record layout info of this variant. */
1446 tree size = TYPE_SIZE (type);
1447 tree size_unit = TYPE_SIZE_UNIT (type);
1448 unsigned int align = TYPE_ALIGN (type);
1449 unsigned int user_align = TYPE_USER_ALIGN (type);
1450 enum machine_mode mode = TYPE_MODE (type);
1452 /* Copy it into all variants. */
1453 for (variant = TYPE_MAIN_VARIANT (type);
1455 variant = TYPE_NEXT_VARIANT (variant))
1457 TYPE_SIZE (variant) = size;
1458 TYPE_SIZE_UNIT (variant) = size_unit;
1459 TYPE_ALIGN (variant) = align;
1460 TYPE_USER_ALIGN (variant) = user_align;
1461 TYPE_MODE (variant) = mode;
1466 /* Do all of the work required to layout the type indicated by RLI,
1467 once the fields have been laid out. This function will call `free'
1468 for RLI, unless FREE_P is false. Passing a value other than false
1469 for FREE_P is bad practice; this option only exists to support the
1473 finish_record_layout (rli, free_p)
1474 record_layout_info rli;
1477 /* Compute the final size. */
1478 finalize_record_size (rli);
1480 /* Compute the TYPE_MODE for the record. */
1481 compute_record_mode (rli->t);
1483 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1484 finalize_type_size (rli->t);
1486 /* Lay out any static members. This is done now because their type
1487 may use the record's type. */
1488 while (rli->pending_statics)
1490 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1491 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1500 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1501 NAME, its fields are chained in reverse on FIELDS.
1503 If ALIGN_TYPE is non-null, it is given the same alignment as
1507 finish_builtin_struct (type, name, fields, align_type)
1515 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1517 DECL_FIELD_CONTEXT (fields) = type;
1518 next = TREE_CHAIN (fields);
1519 TREE_CHAIN (fields) = tail;
1521 TYPE_FIELDS (type) = tail;
1525 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1526 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1530 #if 0 /* not yet, should get fixed properly later */
1531 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1533 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1535 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1536 layout_decl (TYPE_NAME (type), 0);
1539 /* Calculate the mode, size, and alignment for TYPE.
1540 For an array type, calculate the element separation as well.
1541 Record TYPE on the chain of permanent or temporary types
1542 so that dbxout will find out about it.
1544 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1545 layout_type does nothing on such a type.
1547 If the type is incomplete, its TYPE_SIZE remains zero. */
1556 /* Do nothing if type has been laid out before. */
1557 if (TYPE_SIZE (type))
1560 switch (TREE_CODE (type))
1563 /* This kind of type is the responsibility
1564 of the language-specific code. */
1567 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1568 if (TYPE_PRECISION (type) == 0)
1569 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1571 /* ... fall through ... */
1576 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1577 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1578 TREE_UNSIGNED (type) = 1;
1580 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1582 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1583 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1587 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1588 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1589 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1593 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1595 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1596 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1597 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1599 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1600 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1607 subtype = TREE_TYPE (type);
1608 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1609 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1610 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1615 /* This is an incomplete type and so doesn't have a size. */
1616 TYPE_ALIGN (type) = 1;
1617 TYPE_USER_ALIGN (type) = 0;
1618 TYPE_MODE (type) = VOIDmode;
1622 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1623 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1624 /* A pointer might be MODE_PARTIAL_INT,
1625 but ptrdiff_t must be integral. */
1626 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1631 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1632 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1633 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1637 case REFERENCE_TYPE:
1640 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1641 && reference_types_internal)
1642 ? Pmode : TYPE_MODE (type));
1644 int nbits = GET_MODE_BITSIZE (mode);
1646 TYPE_SIZE (type) = bitsize_int (nbits);
1647 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1648 TREE_UNSIGNED (type) = 1;
1649 TYPE_PRECISION (type) = nbits;
1655 tree index = TYPE_DOMAIN (type);
1656 tree element = TREE_TYPE (type);
1658 build_pointer_type (element);
1660 /* We need to know both bounds in order to compute the size. */
1661 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1662 && TYPE_SIZE (element))
1664 tree ub = TYPE_MAX_VALUE (index);
1665 tree lb = TYPE_MIN_VALUE (index);
1669 /* The initial subtraction should happen in the original type so
1670 that (possible) negative values are handled appropriately. */
1671 length = size_binop (PLUS_EXPR, size_one_node,
1673 fold (build (MINUS_EXPR,
1677 /* Special handling for arrays of bits (for Chill). */
1678 element_size = TYPE_SIZE (element);
1679 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1680 && (integer_zerop (TYPE_MAX_VALUE (element))
1681 || integer_onep (TYPE_MAX_VALUE (element)))
1682 && host_integerp (TYPE_MIN_VALUE (element), 1))
1684 HOST_WIDE_INT maxvalue
1685 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1686 HOST_WIDE_INT minvalue
1687 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1689 if (maxvalue - minvalue == 1
1690 && (maxvalue == 1 || maxvalue == 0))
1691 element_size = integer_one_node;
1694 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1695 convert (bitsizetype, length));
1697 /* If we know the size of the element, calculate the total
1698 size directly, rather than do some division thing below.
1699 This optimization helps Fortran assumed-size arrays
1700 (where the size of the array is determined at runtime)
1702 Note that we can't do this in the case where the size of
1703 the elements is one bit since TYPE_SIZE_UNIT cannot be
1704 set correctly in that case. */
1705 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1706 TYPE_SIZE_UNIT (type)
1707 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1710 /* Now round the alignment and size,
1711 using machine-dependent criteria if any. */
1713 #ifdef ROUND_TYPE_ALIGN
1715 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1717 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1719 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1721 #ifdef ROUND_TYPE_SIZE
1722 if (TYPE_SIZE (type) != 0)
1725 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1727 /* If the rounding changed the size of the type, remove any
1728 pre-calculated TYPE_SIZE_UNIT. */
1729 if (simple_cst_equal (TYPE_SIZE (type), tmp) != 1)
1730 TYPE_SIZE_UNIT (type) = NULL;
1732 TYPE_SIZE (type) = tmp;
1736 TYPE_MODE (type) = BLKmode;
1737 if (TYPE_SIZE (type) != 0
1738 #ifdef MEMBER_TYPE_FORCES_BLK
1739 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1741 /* BLKmode elements force BLKmode aggregate;
1742 else extract/store fields may lose. */
1743 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1744 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1746 /* One-element arrays get the component type's mode. */
1747 if (simple_cst_equal (TYPE_SIZE (type),
1748 TYPE_SIZE (TREE_TYPE (type))))
1749 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1752 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1754 if (TYPE_MODE (type) != BLKmode
1755 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1756 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1757 && TYPE_MODE (type) != BLKmode)
1759 TYPE_NO_FORCE_BLK (type) = 1;
1760 TYPE_MODE (type) = BLKmode;
1768 case QUAL_UNION_TYPE:
1771 record_layout_info rli;
1773 /* Initialize the layout information. */
1774 rli = start_record_layout (type);
1776 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1777 in the reverse order in building the COND_EXPR that denotes
1778 its size. We reverse them again later. */
1779 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1780 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1782 /* Place all the fields. */
1783 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1784 place_field (rli, field);
1786 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1787 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1789 if (lang_adjust_rli)
1790 (*lang_adjust_rli) (rli);
1792 /* Finish laying out the record. */
1793 finish_record_layout (rli, /*free_p=*/true);
1797 case SET_TYPE: /* Used by Chill and Pascal. */
1798 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1799 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1803 #ifndef SET_WORD_SIZE
1804 #define SET_WORD_SIZE BITS_PER_WORD
1806 unsigned int alignment
1807 = set_alignment ? set_alignment : SET_WORD_SIZE;
1809 = (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
1810 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1);
1812 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1814 if (rounded_size > (int) alignment)
1815 TYPE_MODE (type) = BLKmode;
1817 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1819 TYPE_SIZE (type) = bitsize_int (rounded_size);
1820 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1821 TYPE_ALIGN (type) = alignment;
1822 TYPE_USER_ALIGN (type) = 0;
1823 TYPE_PRECISION (type) = size_in_bits;
1828 /* The size may vary in different languages, so the language front end
1829 should fill in the size. */
1830 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1831 TYPE_USER_ALIGN (type) = 0;
1832 TYPE_MODE (type) = BLKmode;
1839 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1840 records and unions, finish_record_layout already called this
1842 if (TREE_CODE (type) != RECORD_TYPE
1843 && TREE_CODE (type) != UNION_TYPE
1844 && TREE_CODE (type) != QUAL_UNION_TYPE)
1845 finalize_type_size (type);
1847 /* If this type is created before sizetype has been permanently set,
1848 record it so set_sizetype can fix it up. */
1850 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1852 /* If an alias set has been set for this aggregate when it was incomplete,
1853 force it into alias set 0.
1854 This is too conservative, but we cannot call record_component_aliases
1855 here because some frontends still change the aggregates after
1857 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1858 TYPE_ALIAS_SET (type) = 0;
1861 /* Create and return a type for signed integers of PRECISION bits. */
1864 make_signed_type (precision)
1867 tree type = make_node (INTEGER_TYPE);
1869 TYPE_PRECISION (type) = precision;
1871 fixup_signed_type (type);
1875 /* Create and return a type for unsigned integers of PRECISION bits. */
1878 make_unsigned_type (precision)
1881 tree type = make_node (INTEGER_TYPE);
1883 TYPE_PRECISION (type) = precision;
1885 fixup_unsigned_type (type);
1889 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1890 value to enable integer types to be created. */
1893 initialize_sizetypes ()
1895 tree t = make_node (INTEGER_TYPE);
1897 /* Set this so we do something reasonable for the build_int_2 calls
1899 integer_type_node = t;
1901 TYPE_MODE (t) = SImode;
1902 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1903 TYPE_USER_ALIGN (t) = 0;
1904 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1905 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1906 TREE_UNSIGNED (t) = 1;
1907 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1908 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1909 TYPE_IS_SIZETYPE (t) = 1;
1911 /* 1000 avoids problems with possible overflow and is certainly
1912 larger than any size value we'd want to be storing. */
1913 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1915 /* These two must be different nodes because of the caching done in
1918 bitsizetype = copy_node (t);
1919 integer_type_node = 0;
1922 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1923 Also update the type of any standard type's sizes made so far. */
1929 int oprecision = TYPE_PRECISION (type);
1930 /* The *bitsizetype types use a precision that avoids overflows when
1931 calculating signed sizes / offsets in bits. However, when
1932 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1934 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1935 2 * HOST_BITS_PER_WIDE_INT);
1942 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1943 sizetype = copy_node (type);
1944 TYPE_DOMAIN (sizetype) = type;
1945 TYPE_IS_SIZETYPE (sizetype) = 1;
1946 bitsizetype = make_node (INTEGER_TYPE);
1947 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1948 TYPE_PRECISION (bitsizetype) = precision;
1949 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1951 if (TREE_UNSIGNED (type))
1952 fixup_unsigned_type (bitsizetype);
1954 fixup_signed_type (bitsizetype);
1956 layout_type (bitsizetype);
1958 if (TREE_UNSIGNED (type))
1960 usizetype = sizetype;
1961 ubitsizetype = bitsizetype;
1962 ssizetype = copy_node (make_signed_type (oprecision));
1963 sbitsizetype = copy_node (make_signed_type (precision));
1967 ssizetype = sizetype;
1968 sbitsizetype = bitsizetype;
1969 usizetype = copy_node (make_unsigned_type (oprecision));
1970 ubitsizetype = copy_node (make_unsigned_type (precision));
1973 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1975 /* Show is a sizetype, is a main type, and has no pointers to it. */
1976 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1978 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1979 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1980 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1981 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1982 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1985 /* Go down each of the types we already made and set the proper type
1986 for the sizes in them. */
1987 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1989 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE)
1992 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1993 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1996 early_type_list = 0;
2000 /* Set the extreme values of TYPE based on its precision in bits,
2001 then lay it out. Used when make_signed_type won't do
2002 because the tree code is not INTEGER_TYPE.
2003 E.g. for Pascal, when the -fsigned-char option is given. */
2006 fixup_signed_type (type)
2009 int precision = TYPE_PRECISION (type);
2011 /* We can not represent properly constants greater then
2012 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2013 as they are used by i386 vector extensions and friends. */
2014 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2015 precision = HOST_BITS_PER_WIDE_INT * 2;
2017 TYPE_MIN_VALUE (type)
2018 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2019 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
2020 (((HOST_WIDE_INT) (-1)
2021 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2022 ? precision - HOST_BITS_PER_WIDE_INT - 1
2024 TYPE_MAX_VALUE (type)
2025 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2026 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2027 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2028 ? (((HOST_WIDE_INT) 1
2029 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2032 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2033 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2035 /* Lay out the type: set its alignment, size, etc. */
2039 /* Set the extreme values of TYPE based on its precision in bits,
2040 then lay it out. This is used both in `make_unsigned_type'
2041 and for enumeral types. */
2044 fixup_unsigned_type (type)
2047 int precision = TYPE_PRECISION (type);
2049 /* We can not represent properly constants greater then
2050 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2051 as they are used by i386 vector extensions and friends. */
2052 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2053 precision = HOST_BITS_PER_WIDE_INT * 2;
2055 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
2056 TYPE_MAX_VALUE (type)
2057 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
2058 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
2059 precision - HOST_BITS_PER_WIDE_INT > 0
2060 ? ((unsigned HOST_WIDE_INT) ~0
2061 >> (HOST_BITS_PER_WIDE_INT
2062 - (precision - HOST_BITS_PER_WIDE_INT)))
2064 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2065 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2067 /* Lay out the type: set its alignment, size, etc. */
2071 /* Find the best machine mode to use when referencing a bit field of length
2072 BITSIZE bits starting at BITPOS.
2074 The underlying object is known to be aligned to a boundary of ALIGN bits.
2075 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2076 larger than LARGEST_MODE (usually SImode).
2078 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2079 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2080 mode meeting these conditions.
2082 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2083 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2084 all the conditions. */
2087 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
2088 int bitsize, bitpos;
2090 enum machine_mode largest_mode;
2093 enum machine_mode mode;
2094 unsigned int unit = 0;
2096 /* Find the narrowest integer mode that contains the bit field. */
2097 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2098 mode = GET_MODE_WIDER_MODE (mode))
2100 unit = GET_MODE_BITSIZE (mode);
2101 if ((bitpos % unit) + bitsize <= unit)
2105 if (mode == VOIDmode
2106 /* It is tempting to omit the following line
2107 if STRICT_ALIGNMENT is true.
2108 But that is incorrect, since if the bitfield uses part of 3 bytes
2109 and we use a 4-byte mode, we could get a spurious segv
2110 if the extra 4th byte is past the end of memory.
2111 (Though at least one Unix compiler ignores this problem:
2112 that on the Sequent 386 machine. */
2113 || MIN (unit, BIGGEST_ALIGNMENT) > align
2114 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2117 if (SLOW_BYTE_ACCESS && ! volatilep)
2119 enum machine_mode wide_mode = VOIDmode, tmode;
2121 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2122 tmode = GET_MODE_WIDER_MODE (tmode))
2124 unit = GET_MODE_BITSIZE (tmode);
2125 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2126 && unit <= BITS_PER_WORD
2127 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2128 && (largest_mode == VOIDmode
2129 || unit <= GET_MODE_BITSIZE (largest_mode)))
2133 if (wide_mode != VOIDmode)
2140 #include "gt-stor-layout.h"