1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1996, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004 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"
40 /* Set to one when set_sizetype has been called. */
41 static int sizetype_set;
43 /* Data type for the expressions representing sizes of data types.
44 It is the first integer type laid out. */
45 tree sizetype_tab[(int) TYPE_KIND_LAST];
47 /* If nonzero, this is an upper limit on alignment of structure fields.
48 The value is measured in bits. */
49 unsigned int maximum_field_alignment;
51 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
52 May be overridden by front-ends. */
53 unsigned int set_alignment = 0;
55 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
56 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
57 called only by a front end. */
58 static int reference_types_internal = 0;
60 static void finalize_record_size (record_layout_info);
61 static void finalize_type_size (tree);
62 static void place_union_field (record_layout_info, tree);
63 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
64 static int excess_unit_span (HOST_WIDE_INT, HOST_WIDE_INT, HOST_WIDE_INT,
67 extern void debug_rli (record_layout_info);
69 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
71 static GTY(()) tree pending_sizes;
73 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
77 internal_reference_types (void)
79 reference_types_internal = 1;
82 /* Get a list of all the objects put on the pending sizes list. */
85 get_pending_sizes (void)
87 tree chain = pending_sizes;
93 /* Add EXPR to the pending sizes list. */
96 put_pending_size (tree expr)
98 /* Strip any simple arithmetic from EXPR to see if it has an underlying
100 expr = skip_simple_arithmetic (expr);
102 if (TREE_CODE (expr) == SAVE_EXPR)
103 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
106 /* Put a chain of objects into the pending sizes list, which must be
110 put_pending_sizes (tree chain)
115 pending_sizes = chain;
118 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
119 to serve as the actual size-expression for a type or decl. */
122 variable_size (tree size)
126 /* If the language-processor is to take responsibility for variable-sized
127 items (e.g., languages which have elaboration procedures like Ada),
128 just return SIZE unchanged. Likewise for self-referential sizes and
130 if (TREE_CONSTANT (size)
131 || lang_hooks.decls.global_bindings_p () < 0
132 || CONTAINS_PLACEHOLDER_P (size))
135 size = save_expr (size);
137 /* If an array with a variable number of elements is declared, and
138 the elements require destruction, we will emit a cleanup for the
139 array. That cleanup is run both on normal exit from the block
140 and in the exception-handler for the block. Normally, when code
141 is used in both ordinary code and in an exception handler it is
142 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
143 not wish to do that here; the array-size is the same in both
145 save = skip_simple_arithmetic (size);
147 if (cfun && cfun->x_dont_save_pending_sizes_p)
148 /* The front-end doesn't want us to keep a list of the expressions
149 that determine sizes for variable size objects. Trust it. */
152 if (lang_hooks.decls.global_bindings_p ())
154 if (TREE_CONSTANT (size))
155 error ("type size can't be explicitly evaluated");
157 error ("variable-size type declared outside of any function");
159 return size_one_node;
162 put_pending_size (save);
167 #ifndef MAX_FIXED_MODE_SIZE
168 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
171 /* Return the machine mode to use for a nonscalar of SIZE bits. The
172 mode must be in class CLASS, and have exactly that many value bits;
173 it may have padding as well. If LIMIT is nonzero, modes of wider
174 than MAX_FIXED_MODE_SIZE will not be used. */
177 mode_for_size (unsigned int size, enum mode_class class, int limit)
179 enum machine_mode mode;
181 if (limit && size > MAX_FIXED_MODE_SIZE)
184 /* Get the first mode which has this size, in the specified class. */
185 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
186 mode = GET_MODE_WIDER_MODE (mode))
187 if (GET_MODE_PRECISION (mode) == size)
193 /* Similar, except passed a tree node. */
196 mode_for_size_tree (tree size, enum mode_class class, int limit)
198 if (TREE_CODE (size) != INTEGER_CST
199 || TREE_OVERFLOW (size)
200 /* What we really want to say here is that the size can fit in a
201 host integer, but we know there's no way we'd find a mode for
202 this many bits, so there's no point in doing the precise test. */
203 || compare_tree_int (size, 1000) > 0)
206 return mode_for_size (tree_low_cst (size, 1), class, limit);
209 /* Similar, but never return BLKmode; return the narrowest mode that
210 contains at least the requested number of value bits. */
213 smallest_mode_for_size (unsigned int size, enum mode_class class)
215 enum machine_mode mode;
217 /* Get the first mode which has at least this size, in the
219 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
220 mode = GET_MODE_WIDER_MODE (mode))
221 if (GET_MODE_PRECISION (mode) >= size)
227 /* Find an integer mode of the exact same size, or BLKmode on failure. */
230 int_mode_for_mode (enum machine_mode mode)
232 switch (GET_MODE_CLASS (mode))
235 case MODE_PARTIAL_INT:
238 case MODE_COMPLEX_INT:
239 case MODE_COMPLEX_FLOAT:
241 case MODE_VECTOR_INT:
242 case MODE_VECTOR_FLOAT:
243 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
250 /* ... fall through ... */
260 /* Return the alignment of MODE. This will be bounded by 1 and
261 BIGGEST_ALIGNMENT. */
264 get_mode_alignment (enum machine_mode mode)
266 return MIN (BIGGEST_ALIGNMENT, MAX (1, mode_base_align[mode]*BITS_PER_UNIT));
270 /* Subroutine of layout_decl: Force alignment required for the data type.
271 But if the decl itself wants greater alignment, don't override that. */
274 do_type_align (tree type, tree decl)
276 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
278 DECL_ALIGN (decl) = TYPE_ALIGN (type);
279 if (TREE_CODE (decl) == FIELD_DECL)
280 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
284 /* Set the size, mode and alignment of a ..._DECL node.
285 TYPE_DECL does need this for C++.
286 Note that LABEL_DECL and CONST_DECL nodes do not need this,
287 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
288 Don't call layout_decl for them.
290 KNOWN_ALIGN is the amount of alignment we can assume this
291 decl has with no special effort. It is relevant only for FIELD_DECLs
292 and depends on the previous fields.
293 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
294 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
295 the record will be aligned to suit. */
298 layout_decl (tree decl, unsigned int known_align)
300 tree type = TREE_TYPE (decl);
301 enum tree_code code = TREE_CODE (decl);
304 if (code == CONST_DECL)
306 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
307 && code != TYPE_DECL && code != FIELD_DECL)
310 rtl = DECL_RTL_IF_SET (decl);
312 if (type == error_mark_node)
313 type = void_type_node;
315 /* Usually the size and mode come from the data type without change,
316 however, the front-end may set the explicit width of the field, so its
317 size may not be the same as the size of its type. This happens with
318 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
319 also happens with other fields. For example, the C++ front-end creates
320 zero-sized fields corresponding to empty base classes, and depends on
321 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
322 size in bytes from the size in bits. If we have already set the mode,
323 don't set it again since we can be called twice for FIELD_DECLs. */
325 DECL_UNSIGNED (decl) = TYPE_UNSIGNED (type);
326 if (DECL_MODE (decl) == VOIDmode)
327 DECL_MODE (decl) = TYPE_MODE (type);
329 if (DECL_SIZE (decl) == 0)
331 DECL_SIZE (decl) = TYPE_SIZE (type);
332 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
334 else if (DECL_SIZE_UNIT (decl) == 0)
335 DECL_SIZE_UNIT (decl)
336 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
339 if (code != FIELD_DECL)
340 /* For non-fields, update the alignment from the type. */
341 do_type_align (type, decl);
343 /* For fields, it's a bit more complicated... */
345 bool old_user_align = DECL_USER_ALIGN (decl);
347 if (DECL_BIT_FIELD (decl))
349 DECL_BIT_FIELD_TYPE (decl) = type;
351 /* A zero-length bit-field affects the alignment of the next
353 if (integer_zerop (DECL_SIZE (decl))
354 && ! DECL_PACKED (decl)
355 && ! targetm.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl)))
357 #ifdef PCC_BITFIELD_TYPE_MATTERS
358 if (PCC_BITFIELD_TYPE_MATTERS)
359 do_type_align (type, decl);
363 #ifdef EMPTY_FIELD_BOUNDARY
364 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
366 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
367 DECL_USER_ALIGN (decl) = 0;
373 /* See if we can use an ordinary integer mode for a bit-field.
374 Conditions are: a fixed size that is correct for another mode
375 and occupying a complete byte or bytes on proper boundary. */
376 if (TYPE_SIZE (type) != 0
377 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
378 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
380 enum machine_mode xmode
381 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
385 || known_align >= GET_MODE_ALIGNMENT (xmode)))
387 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
389 DECL_MODE (decl) = xmode;
390 DECL_BIT_FIELD (decl) = 0;
394 /* Turn off DECL_BIT_FIELD if we won't need it set. */
395 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
396 && known_align >= TYPE_ALIGN (type)
397 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
398 DECL_BIT_FIELD (decl) = 0;
400 else if (DECL_PACKED (decl) && DECL_USER_ALIGN (decl))
401 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
402 round up; we'll reduce it again below. We want packing to
403 supersede USER_ALIGN inherited from the type, but defer to
404 alignment explicitly specified on the field decl. */;
406 do_type_align (type, decl);
408 /* If the field is of variable size, we can't misalign it since we
409 have no way to make a temporary to align the result. But this
410 isn't an issue if the decl is not addressable. Likewise if it
413 Note that do_type_align may set DECL_USER_ALIGN, so we need to
414 check old_user_align instead. */
415 if (DECL_PACKED (decl)
417 && (DECL_NONADDRESSABLE_P (decl)
418 || DECL_SIZE_UNIT (decl) == 0
419 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
420 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
422 if (! DECL_USER_ALIGN (decl) && ! DECL_PACKED (decl))
424 /* Some targets (i.e. i386, VMS) limit struct field alignment
425 to a lower boundary than alignment of variables unless
426 it was overridden by attribute aligned. */
427 #ifdef BIGGEST_FIELD_ALIGNMENT
429 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
431 #ifdef ADJUST_FIELD_ALIGN
432 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
436 /* Should this be controlled by DECL_USER_ALIGN, too? */
437 if (maximum_field_alignment != 0)
438 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
441 /* Evaluate nonconstant size only once, either now or as soon as safe. */
442 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
443 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
444 if (DECL_SIZE_UNIT (decl) != 0
445 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
446 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
448 /* If requested, warn about definitions of large data objects. */
450 && (code == VAR_DECL || code == PARM_DECL)
451 && ! DECL_EXTERNAL (decl))
453 tree size = DECL_SIZE_UNIT (decl);
455 if (size != 0 && TREE_CODE (size) == INTEGER_CST
456 && compare_tree_int (size, larger_than_size) > 0)
458 int size_as_int = TREE_INT_CST_LOW (size);
460 if (compare_tree_int (size, size_as_int) == 0)
461 warning ("%Jsize of '%D' is %d bytes", decl, decl, size_as_int);
463 warning ("%Jsize of '%D' is larger than %d bytes",
464 decl, decl, larger_than_size);
468 /* If the RTL was already set, update its mode and mem attributes. */
471 PUT_MODE (rtl, DECL_MODE (decl));
472 SET_DECL_RTL (decl, 0);
473 set_mem_attributes (rtl, decl, 1);
474 SET_DECL_RTL (decl, rtl);
478 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
479 a previous call to layout_decl and calls it again. */
482 relayout_decl (tree decl)
484 DECL_SIZE (decl) = DECL_SIZE_UNIT (decl) = 0;
485 DECL_MODE (decl) = VOIDmode;
486 DECL_ALIGN (decl) = 0;
487 SET_DECL_RTL (decl, 0);
489 layout_decl (decl, 0);
492 /* Hook for a front-end function that can modify the record layout as needed
493 immediately before it is finalized. */
495 void (*lang_adjust_rli) (record_layout_info) = 0;
498 set_lang_adjust_rli (void (*f) (record_layout_info))
503 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
504 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
505 is to be passed to all other layout functions for this record. It is the
506 responsibility of the caller to call `free' for the storage returned.
507 Note that garbage collection is not permitted until we finish laying
511 start_record_layout (tree t)
513 record_layout_info rli = xmalloc (sizeof (struct record_layout_info_s));
517 /* If the type has a minimum specified alignment (via an attribute
518 declaration, for example) use it -- otherwise, start with a
519 one-byte alignment. */
520 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
521 rli->unpacked_align = rli->record_align;
522 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
524 #ifdef STRUCTURE_SIZE_BOUNDARY
525 /* Packed structures don't need to have minimum size. */
526 if (! TYPE_PACKED (t))
527 rli->record_align = MAX (rli->record_align, (unsigned) STRUCTURE_SIZE_BOUNDARY);
530 rli->offset = size_zero_node;
531 rli->bitpos = bitsize_zero_node;
533 rli->pending_statics = 0;
534 rli->packed_maybe_necessary = 0;
539 /* These four routines perform computations that convert between
540 the offset/bitpos forms and byte and bit offsets. */
543 bit_from_pos (tree offset, tree bitpos)
545 return size_binop (PLUS_EXPR, bitpos,
546 size_binop (MULT_EXPR, convert (bitsizetype, offset),
551 byte_from_pos (tree offset, tree bitpos)
553 return size_binop (PLUS_EXPR, offset,
555 size_binop (TRUNC_DIV_EXPR, bitpos,
556 bitsize_unit_node)));
560 pos_from_bit (tree *poffset, tree *pbitpos, unsigned int off_align,
563 *poffset = size_binop (MULT_EXPR,
565 size_binop (FLOOR_DIV_EXPR, pos,
566 bitsize_int (off_align))),
567 size_int (off_align / BITS_PER_UNIT));
568 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
571 /* Given a pointer to bit and byte offsets and an offset alignment,
572 normalize the offsets so they are within the alignment. */
575 normalize_offset (tree *poffset, tree *pbitpos, unsigned int off_align)
577 /* If the bit position is now larger than it should be, adjust it
579 if (compare_tree_int (*pbitpos, off_align) >= 0)
581 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
582 bitsize_int (off_align));
585 = size_binop (PLUS_EXPR, *poffset,
586 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
587 size_int (off_align / BITS_PER_UNIT)));
590 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
594 /* Print debugging information about the information in RLI. */
597 debug_rli (record_layout_info rli)
599 print_node_brief (stderr, "type", rli->t, 0);
600 print_node_brief (stderr, "\noffset", rli->offset, 0);
601 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
603 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
604 rli->record_align, rli->unpacked_align,
606 if (rli->packed_maybe_necessary)
607 fprintf (stderr, "packed may be necessary\n");
609 if (rli->pending_statics)
611 fprintf (stderr, "pending statics:\n");
612 debug_tree (rli->pending_statics);
616 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
617 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
620 normalize_rli (record_layout_info rli)
622 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
625 /* Returns the size in bytes allocated so far. */
628 rli_size_unit_so_far (record_layout_info rli)
630 return byte_from_pos (rli->offset, rli->bitpos);
633 /* Returns the size in bits allocated so far. */
636 rli_size_so_far (record_layout_info rli)
638 return bit_from_pos (rli->offset, rli->bitpos);
641 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
642 the next available location is given by KNOWN_ALIGN. Update the
643 variable alignment fields in RLI, and return the alignment to give
647 update_alignment_for_field (record_layout_info rli, tree field,
648 unsigned int known_align)
650 /* The alignment required for FIELD. */
651 unsigned int desired_align;
652 /* The type of this field. */
653 tree type = TREE_TYPE (field);
654 /* True if the field was explicitly aligned by the user. */
658 /* Lay out the field so we know what alignment it needs. */
659 layout_decl (field, known_align);
660 desired_align = DECL_ALIGN (field);
661 user_align = DECL_USER_ALIGN (field);
663 is_bitfield = (type != error_mark_node
664 && DECL_BIT_FIELD_TYPE (field)
665 && ! integer_zerop (TYPE_SIZE (type)));
667 /* Record must have at least as much alignment as any field.
668 Otherwise, the alignment of the field within the record is
670 if (is_bitfield && targetm.ms_bitfield_layout_p (rli->t))
672 /* Here, the alignment of the underlying type of a bitfield can
673 affect the alignment of a record; even a zero-sized field
674 can do this. The alignment should be to the alignment of
675 the type, except that for zero-size bitfields this only
676 applies if there was an immediately prior, nonzero-size
677 bitfield. (That's the way it is, experimentally.) */
678 if (! integer_zerop (DECL_SIZE (field))
679 ? ! DECL_PACKED (field)
681 && DECL_BIT_FIELD_TYPE (rli->prev_field)
682 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
684 unsigned int type_align = TYPE_ALIGN (type);
685 type_align = MAX (type_align, desired_align);
686 if (maximum_field_alignment != 0)
687 type_align = MIN (type_align, maximum_field_alignment);
688 rli->record_align = MAX (rli->record_align, type_align);
689 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
692 #ifdef PCC_BITFIELD_TYPE_MATTERS
693 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
695 /* Named bit-fields cause the entire structure to have the
696 alignment implied by their type. Some targets also apply the same
697 rules to unnamed bitfields. */
698 if (DECL_NAME (field) != 0
699 || targetm.align_anon_bitfield ())
701 unsigned int type_align = TYPE_ALIGN (type);
703 #ifdef ADJUST_FIELD_ALIGN
704 if (! TYPE_USER_ALIGN (type))
705 type_align = ADJUST_FIELD_ALIGN (field, type_align);
708 if (maximum_field_alignment != 0)
709 type_align = MIN (type_align, maximum_field_alignment);
710 else if (DECL_PACKED (field))
711 type_align = MIN (type_align, BITS_PER_UNIT);
713 /* The alignment of the record is increased to the maximum
714 of the current alignment, the alignment indicated on the
715 field (i.e., the alignment specified by an __aligned__
716 attribute), and the alignment indicated by the type of
718 rli->record_align = MAX (rli->record_align, desired_align);
719 rli->record_align = MAX (rli->record_align, type_align);
722 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
723 user_align |= TYPE_USER_ALIGN (type);
729 rli->record_align = MAX (rli->record_align, desired_align);
730 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
733 TYPE_USER_ALIGN (rli->t) |= user_align;
735 return desired_align;
738 /* Called from place_field to handle unions. */
741 place_union_field (record_layout_info rli, tree field)
743 update_alignment_for_field (rli, field, /*known_align=*/0);
745 DECL_FIELD_OFFSET (field) = size_zero_node;
746 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
747 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
749 /* We assume the union's size will be a multiple of a byte so we don't
750 bother with BITPOS. */
751 if (TREE_CODE (rli->t) == UNION_TYPE)
752 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
753 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
754 rli->offset = fold (build3 (COND_EXPR, sizetype,
755 DECL_QUALIFIER (field),
756 DECL_SIZE_UNIT (field), rli->offset));
759 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
760 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
761 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
762 units of alignment than the underlying TYPE. */
764 excess_unit_span (HOST_WIDE_INT byte_offset, HOST_WIDE_INT bit_offset,
765 HOST_WIDE_INT size, HOST_WIDE_INT align, tree type)
767 /* Note that the calculation of OFFSET might overflow; we calculate it so
768 that we still get the right result as long as ALIGN is a power of two. */
769 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
771 offset = offset % align;
772 return ((offset + size + align - 1) / align
773 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
778 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
779 is a FIELD_DECL to be added after those fields already present in
780 T. (FIELD is not actually added to the TYPE_FIELDS list here;
781 callers that desire that behavior must manually perform that step.) */
784 place_field (record_layout_info rli, tree field)
786 /* The alignment required for FIELD. */
787 unsigned int desired_align;
788 /* The alignment FIELD would have if we just dropped it into the
789 record as it presently stands. */
790 unsigned int known_align;
791 unsigned int actual_align;
792 /* The type of this field. */
793 tree type = TREE_TYPE (field);
795 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
798 /* If FIELD is static, then treat it like a separate variable, not
799 really like a structure field. If it is a FUNCTION_DECL, it's a
800 method. In both cases, all we do is lay out the decl, and we do
801 it *after* the record is laid out. */
802 if (TREE_CODE (field) == VAR_DECL)
804 rli->pending_statics = tree_cons (NULL_TREE, field,
805 rli->pending_statics);
809 /* Enumerators and enum types which are local to this class need not
810 be laid out. Likewise for initialized constant fields. */
811 else if (TREE_CODE (field) != FIELD_DECL)
814 /* Unions are laid out very differently than records, so split
815 that code off to another function. */
816 else if (TREE_CODE (rli->t) != RECORD_TYPE)
818 place_union_field (rli, field);
822 /* Work out the known alignment so far. Note that A & (-A) is the
823 value of the least-significant bit in A that is one. */
824 if (! integer_zerop (rli->bitpos))
825 known_align = (tree_low_cst (rli->bitpos, 1)
826 & - tree_low_cst (rli->bitpos, 1));
827 else if (integer_zerop (rli->offset))
828 known_align = BIGGEST_ALIGNMENT;
829 else if (host_integerp (rli->offset, 1))
830 known_align = (BITS_PER_UNIT
831 * (tree_low_cst (rli->offset, 1)
832 & - tree_low_cst (rli->offset, 1)));
834 known_align = rli->offset_align;
836 desired_align = update_alignment_for_field (rli, field, known_align);
838 if (warn_packed && DECL_PACKED (field))
840 if (known_align >= TYPE_ALIGN (type))
842 if (TYPE_ALIGN (type) > desired_align)
844 if (STRICT_ALIGNMENT)
845 warning ("%Jpacked attribute causes inefficient alignment "
846 "for '%D'", field, field);
848 warning ("%Jpacked attribute is unnecessary for '%D'",
853 rli->packed_maybe_necessary = 1;
856 /* Does this field automatically have alignment it needs by virtue
857 of the fields that precede it and the record's own alignment? */
858 if (known_align < desired_align)
860 /* No, we need to skip space before this field.
861 Bump the cumulative size to multiple of field alignment. */
864 warning ("%Jpadding struct to align '%D'", field, field);
866 /* If the alignment is still within offset_align, just align
868 if (desired_align < rli->offset_align)
869 rli->bitpos = round_up (rli->bitpos, desired_align);
872 /* First adjust OFFSET by the partial bits, then align. */
874 = size_binop (PLUS_EXPR, rli->offset,
876 size_binop (CEIL_DIV_EXPR, rli->bitpos,
877 bitsize_unit_node)));
878 rli->bitpos = bitsize_zero_node;
880 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
883 if (! TREE_CONSTANT (rli->offset))
884 rli->offset_align = desired_align;
888 /* Handle compatibility with PCC. Note that if the record has any
889 variable-sized fields, we need not worry about compatibility. */
890 #ifdef PCC_BITFIELD_TYPE_MATTERS
891 if (PCC_BITFIELD_TYPE_MATTERS
892 && ! targetm.ms_bitfield_layout_p (rli->t)
893 && TREE_CODE (field) == FIELD_DECL
894 && type != error_mark_node
895 && DECL_BIT_FIELD (field)
896 && ! DECL_PACKED (field)
897 && maximum_field_alignment == 0
898 && ! integer_zerop (DECL_SIZE (field))
899 && host_integerp (DECL_SIZE (field), 1)
900 && host_integerp (rli->offset, 1)
901 && host_integerp (TYPE_SIZE (type), 1))
903 unsigned int type_align = TYPE_ALIGN (type);
904 tree dsize = DECL_SIZE (field);
905 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
906 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
907 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
909 #ifdef ADJUST_FIELD_ALIGN
910 if (! TYPE_USER_ALIGN (type))
911 type_align = ADJUST_FIELD_ALIGN (field, type_align);
914 /* A bit field may not span more units of alignment of its type
915 than its type itself. Advance to next boundary if necessary. */
916 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
917 rli->bitpos = round_up (rli->bitpos, type_align);
919 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
923 #ifdef BITFIELD_NBYTES_LIMITED
924 if (BITFIELD_NBYTES_LIMITED
925 && ! targetm.ms_bitfield_layout_p (rli->t)
926 && TREE_CODE (field) == FIELD_DECL
927 && type != error_mark_node
928 && DECL_BIT_FIELD_TYPE (field)
929 && ! DECL_PACKED (field)
930 && ! integer_zerop (DECL_SIZE (field))
931 && host_integerp (DECL_SIZE (field), 1)
932 && host_integerp (rli->offset, 1)
933 && host_integerp (TYPE_SIZE (type), 1))
935 unsigned int type_align = TYPE_ALIGN (type);
936 tree dsize = DECL_SIZE (field);
937 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
938 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
939 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
941 #ifdef ADJUST_FIELD_ALIGN
942 if (! TYPE_USER_ALIGN (type))
943 type_align = ADJUST_FIELD_ALIGN (field, type_align);
946 if (maximum_field_alignment != 0)
947 type_align = MIN (type_align, maximum_field_alignment);
948 /* ??? This test is opposite the test in the containing if
949 statement, so this code is unreachable currently. */
950 else if (DECL_PACKED (field))
951 type_align = MIN (type_align, BITS_PER_UNIT);
953 /* A bit field may not span the unit of alignment of its type.
954 Advance to next boundary if necessary. */
955 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
956 rli->bitpos = round_up (rli->bitpos, type_align);
958 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
962 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
964 When a bit field is inserted into a packed record, the whole
965 size of the underlying type is used by one or more same-size
966 adjacent bitfields. (That is, if its long:3, 32 bits is
967 used in the record, and any additional adjacent long bitfields are
968 packed into the same chunk of 32 bits. However, if the size
969 changes, a new field of that size is allocated.) In an unpacked
970 record, this is the same as using alignment, but not equivalent
973 Note: for compatibility, we use the type size, not the type alignment
974 to determine alignment, since that matches the documentation */
976 if (targetm.ms_bitfield_layout_p (rli->t)
977 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
978 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
980 /* At this point, either the prior or current are bitfields,
981 (possibly both), and we're dealing with MS packing. */
982 tree prev_saved = rli->prev_field;
984 /* Is the prior field a bitfield? If so, handle "runs" of same
986 if (rli->prev_field /* necessarily a bitfield if it exists. */)
988 /* If both are bitfields, nonzero, and the same size, this is
989 the middle of a run. Zero declared size fields are special
990 and handled as "end of run". (Note: it's nonzero declared
991 size, but equal type sizes!) (Since we know that both
992 the current and previous fields are bitfields by the
993 time we check it, DECL_SIZE must be present for both.) */
994 if (DECL_BIT_FIELD_TYPE (field)
995 && !integer_zerop (DECL_SIZE (field))
996 && !integer_zerop (DECL_SIZE (rli->prev_field))
997 && host_integerp (DECL_SIZE (rli->prev_field), 0)
998 && host_integerp (TYPE_SIZE (type), 0)
999 && simple_cst_equal (TYPE_SIZE (type),
1000 TYPE_SIZE (TREE_TYPE (rli->prev_field))))
1002 /* We're in the middle of a run of equal type size fields; make
1003 sure we realign if we run out of bits. (Not decl size,
1005 HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 0);
1007 if (rli->remaining_in_alignment < bitsize)
1009 /* out of bits; bump up to next 'word'. */
1010 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1012 = size_binop (PLUS_EXPR, TYPE_SIZE (type),
1013 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1014 rli->prev_field = field;
1015 rli->remaining_in_alignment
1016 = tree_low_cst (TYPE_SIZE (type), 0);
1019 rli->remaining_in_alignment -= bitsize;
1023 /* End of a run: if leaving a run of bitfields of the same type
1024 size, we have to "use up" the rest of the bits of the type
1027 Compute the new position as the sum of the size for the prior
1028 type and where we first started working on that type.
1029 Note: since the beginning of the field was aligned then
1030 of course the end will be too. No round needed. */
1032 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1034 tree type_size = TYPE_SIZE (TREE_TYPE (rli->prev_field));
1037 = size_binop (PLUS_EXPR, type_size,
1038 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1041 /* We "use up" size zero fields; the code below should behave
1042 as if the prior field was not a bitfield. */
1045 /* Cause a new bitfield to be captured, either this time (if
1046 currently a bitfield) or next time we see one. */
1047 if (!DECL_BIT_FIELD_TYPE(field)
1048 || integer_zerop (DECL_SIZE (field)))
1049 rli->prev_field = NULL;
1052 normalize_rli (rli);
1055 /* If we're starting a new run of same size type bitfields
1056 (or a run of non-bitfields), set up the "first of the run"
1059 That is, if the current field is not a bitfield, or if there
1060 was a prior bitfield the type sizes differ, or if there wasn't
1061 a prior bitfield the size of the current field is nonzero.
1063 Note: we must be sure to test ONLY the type size if there was
1064 a prior bitfield and ONLY for the current field being zero if
1067 if (!DECL_BIT_FIELD_TYPE (field)
1068 || ( prev_saved != NULL
1069 ? !simple_cst_equal (TYPE_SIZE (type),
1070 TYPE_SIZE (TREE_TYPE (prev_saved)))
1071 : !integer_zerop (DECL_SIZE (field)) ))
1073 /* Never smaller than a byte for compatibility. */
1074 unsigned int type_align = BITS_PER_UNIT;
1076 /* (When not a bitfield), we could be seeing a flex array (with
1077 no DECL_SIZE). Since we won't be using remaining_in_alignment
1078 until we see a bitfield (and come by here again) we just skip
1080 if (DECL_SIZE (field) != NULL
1081 && host_integerp (TYPE_SIZE (TREE_TYPE (field)), 0)
1082 && host_integerp (DECL_SIZE (field), 0))
1083 rli->remaining_in_alignment
1084 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field)), 0)
1085 - tree_low_cst (DECL_SIZE (field), 0);
1087 /* Now align (conventionally) for the new type. */
1088 if (!DECL_PACKED(field))
1089 type_align = MAX(TYPE_ALIGN (type), type_align);
1092 && DECL_BIT_FIELD_TYPE (prev_saved)
1093 /* If the previous bit-field is zero-sized, we've already
1094 accounted for its alignment needs (or ignored it, if
1095 appropriate) while placing it. */
1096 && ! integer_zerop (DECL_SIZE (prev_saved)))
1097 type_align = MAX (type_align,
1098 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1100 if (maximum_field_alignment != 0)
1101 type_align = MIN (type_align, maximum_field_alignment);
1103 rli->bitpos = round_up (rli->bitpos, type_align);
1105 /* If we really aligned, don't allow subsequent bitfields
1107 rli->prev_field = NULL;
1111 /* Offset so far becomes the position of this field after normalizing. */
1112 normalize_rli (rli);
1113 DECL_FIELD_OFFSET (field) = rli->offset;
1114 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1115 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1117 /* If this field ended up more aligned than we thought it would be (we
1118 approximate this by seeing if its position changed), lay out the field
1119 again; perhaps we can use an integral mode for it now. */
1120 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1121 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1122 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1123 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1124 actual_align = BIGGEST_ALIGNMENT;
1125 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1126 actual_align = (BITS_PER_UNIT
1127 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1128 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1130 actual_align = DECL_OFFSET_ALIGN (field);
1132 if (known_align != actual_align)
1133 layout_decl (field, actual_align);
1135 /* Only the MS bitfields use this. */
1136 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1137 rli->prev_field = field;
1139 /* Now add size of this field to the size of the record. If the size is
1140 not constant, treat the field as being a multiple of bytes and just
1141 adjust the offset, resetting the bit position. Otherwise, apportion the
1142 size amongst the bit position and offset. First handle the case of an
1143 unspecified size, which can happen when we have an invalid nested struct
1144 definition, such as struct j { struct j { int i; } }. The error message
1145 is printed in finish_struct. */
1146 if (DECL_SIZE (field) == 0)
1148 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1149 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1152 = size_binop (PLUS_EXPR, rli->offset,
1154 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1155 bitsize_unit_node)));
1157 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1158 rli->bitpos = bitsize_zero_node;
1159 rli->offset_align = MIN (rli->offset_align, desired_align);
1163 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1164 normalize_rli (rli);
1168 /* Assuming that all the fields have been laid out, this function uses
1169 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1170 indicated by RLI. */
1173 finalize_record_size (record_layout_info rli)
1175 tree unpadded_size, unpadded_size_unit;
1177 /* Now we want just byte and bit offsets, so set the offset alignment
1178 to be a byte and then normalize. */
1179 rli->offset_align = BITS_PER_UNIT;
1180 normalize_rli (rli);
1182 /* Determine the desired alignment. */
1183 #ifdef ROUND_TYPE_ALIGN
1184 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1187 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1190 /* Compute the size so far. Be sure to allow for extra bits in the
1191 size in bytes. We have guaranteed above that it will be no more
1192 than a single byte. */
1193 unpadded_size = rli_size_so_far (rli);
1194 unpadded_size_unit = rli_size_unit_so_far (rli);
1195 if (! integer_zerop (rli->bitpos))
1197 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1199 /* Round the size up to be a multiple of the required alignment. */
1200 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1201 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1202 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1204 if (warn_padded && TREE_CONSTANT (unpadded_size)
1205 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1206 warning ("padding struct size to alignment boundary");
1208 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1209 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1210 && TREE_CONSTANT (unpadded_size))
1214 #ifdef ROUND_TYPE_ALIGN
1216 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1218 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1221 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1222 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1224 TYPE_PACKED (rli->t) = 0;
1226 if (TYPE_NAME (rli->t))
1230 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1231 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1233 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1235 if (STRICT_ALIGNMENT)
1236 warning ("packed attribute causes inefficient alignment for `%s'", name);
1238 warning ("packed attribute is unnecessary for `%s'", name);
1242 if (STRICT_ALIGNMENT)
1243 warning ("packed attribute causes inefficient alignment");
1245 warning ("packed attribute is unnecessary");
1251 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1254 compute_record_mode (tree type)
1257 enum machine_mode mode = VOIDmode;
1259 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1260 However, if possible, we use a mode that fits in a register
1261 instead, in order to allow for better optimization down the
1263 TYPE_MODE (type) = BLKmode;
1265 if (! host_integerp (TYPE_SIZE (type), 1))
1268 /* A record which has any BLKmode members must itself be
1269 BLKmode; it can't go in a register. Unless the member is
1270 BLKmode only because it isn't aligned. */
1271 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1273 if (TREE_CODE (field) != FIELD_DECL)
1276 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1277 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1278 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))
1279 && !(TYPE_SIZE (TREE_TYPE (field)) != 0
1280 && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))))
1281 || ! host_integerp (bit_position (field), 1)
1282 || DECL_SIZE (field) == 0
1283 || ! host_integerp (DECL_SIZE (field), 1))
1286 /* If this field is the whole struct, remember its mode so
1287 that, say, we can put a double in a class into a DF
1288 register instead of forcing it to live in the stack. */
1289 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1290 mode = DECL_MODE (field);
1292 #ifdef MEMBER_TYPE_FORCES_BLK
1293 /* With some targets, eg. c4x, it is sub-optimal
1294 to access an aligned BLKmode structure as a scalar. */
1296 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1298 #endif /* MEMBER_TYPE_FORCES_BLK */
1301 /* If we only have one real field; use its mode. This only applies to
1302 RECORD_TYPE. This does not apply to unions. */
1303 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1304 TYPE_MODE (type) = mode;
1306 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1308 /* If structure's known alignment is less than what the scalar
1309 mode would need, and it matters, then stick with BLKmode. */
1310 if (TYPE_MODE (type) != BLKmode
1312 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1313 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1315 /* If this is the only reason this type is BLKmode, then
1316 don't force containing types to be BLKmode. */
1317 TYPE_NO_FORCE_BLK (type) = 1;
1318 TYPE_MODE (type) = BLKmode;
1322 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1326 finalize_type_size (tree type)
1328 /* Normally, use the alignment corresponding to the mode chosen.
1329 However, where strict alignment is not required, avoid
1330 over-aligning structures, since most compilers do not do this
1333 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1334 && (STRICT_ALIGNMENT
1335 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1336 && TREE_CODE (type) != QUAL_UNION_TYPE
1337 && TREE_CODE (type) != ARRAY_TYPE)))
1339 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1340 TYPE_USER_ALIGN (type) = 0;
1343 /* Do machine-dependent extra alignment. */
1344 #ifdef ROUND_TYPE_ALIGN
1346 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1349 /* If we failed to find a simple way to calculate the unit size
1350 of the type, find it by division. */
1351 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1352 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1353 result will fit in sizetype. We will get more efficient code using
1354 sizetype, so we force a conversion. */
1355 TYPE_SIZE_UNIT (type)
1356 = convert (sizetype,
1357 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1358 bitsize_unit_node));
1360 if (TYPE_SIZE (type) != 0)
1362 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1363 TYPE_SIZE_UNIT (type)
1364 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1367 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1368 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1369 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1370 if (TYPE_SIZE_UNIT (type) != 0
1371 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1372 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1374 /* Also layout any other variants of the type. */
1375 if (TYPE_NEXT_VARIANT (type)
1376 || type != TYPE_MAIN_VARIANT (type))
1379 /* Record layout info of this variant. */
1380 tree size = TYPE_SIZE (type);
1381 tree size_unit = TYPE_SIZE_UNIT (type);
1382 unsigned int align = TYPE_ALIGN (type);
1383 unsigned int user_align = TYPE_USER_ALIGN (type);
1384 enum machine_mode mode = TYPE_MODE (type);
1386 /* Copy it into all variants. */
1387 for (variant = TYPE_MAIN_VARIANT (type);
1389 variant = TYPE_NEXT_VARIANT (variant))
1391 TYPE_SIZE (variant) = size;
1392 TYPE_SIZE_UNIT (variant) = size_unit;
1393 TYPE_ALIGN (variant) = align;
1394 TYPE_USER_ALIGN (variant) = user_align;
1395 TYPE_MODE (variant) = mode;
1400 /* Do all of the work required to layout the type indicated by RLI,
1401 once the fields have been laid out. This function will call `free'
1402 for RLI, unless FREE_P is false. Passing a value other than false
1403 for FREE_P is bad practice; this option only exists to support the
1407 finish_record_layout (record_layout_info rli, int free_p)
1409 /* Compute the final size. */
1410 finalize_record_size (rli);
1412 /* Compute the TYPE_MODE for the record. */
1413 compute_record_mode (rli->t);
1415 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1416 finalize_type_size (rli->t);
1418 /* Lay out any static members. This is done now because their type
1419 may use the record's type. */
1420 while (rli->pending_statics)
1422 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1423 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1432 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1433 NAME, its fields are chained in reverse on FIELDS.
1435 If ALIGN_TYPE is non-null, it is given the same alignment as
1439 finish_builtin_struct (tree type, const char *name, tree fields,
1444 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1446 DECL_FIELD_CONTEXT (fields) = type;
1447 next = TREE_CHAIN (fields);
1448 TREE_CHAIN (fields) = tail;
1450 TYPE_FIELDS (type) = tail;
1454 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1455 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1459 #if 0 /* not yet, should get fixed properly later */
1460 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1462 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1464 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1465 layout_decl (TYPE_NAME (type), 0);
1468 /* Calculate the mode, size, and alignment for TYPE.
1469 For an array type, calculate the element separation as well.
1470 Record TYPE on the chain of permanent or temporary types
1471 so that dbxout will find out about it.
1473 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1474 layout_type does nothing on such a type.
1476 If the type is incomplete, its TYPE_SIZE remains zero. */
1479 layout_type (tree type)
1484 if (type == error_mark_node)
1487 /* Do nothing if type has been laid out before. */
1488 if (TYPE_SIZE (type))
1491 switch (TREE_CODE (type))
1494 /* This kind of type is the responsibility
1495 of the language-specific code. */
1498 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1499 if (TYPE_PRECISION (type) == 0)
1500 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1502 /* ... fall through ... */
1507 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1508 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1509 TYPE_UNSIGNED (type) = 1;
1511 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1513 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1514 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1518 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1519 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1520 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1524 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1526 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1527 (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE
1528 ? MODE_COMPLEX_FLOAT : MODE_COMPLEX_INT),
1530 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1531 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1536 int nunits = TYPE_VECTOR_SUBPARTS (type);
1537 tree nunits_tree = build_int_cst (NULL_TREE, nunits, 0);
1538 tree innertype = TREE_TYPE (type);
1540 if (nunits & (nunits - 1))
1543 /* Find an appropriate mode for the vector type. */
1544 if (TYPE_MODE (type) == VOIDmode)
1546 enum machine_mode innermode = TYPE_MODE (innertype);
1547 enum machine_mode mode;
1549 /* First, look for a supported vector type. */
1550 if (GET_MODE_CLASS (innermode) == MODE_FLOAT)
1551 mode = MIN_MODE_VECTOR_FLOAT;
1553 mode = MIN_MODE_VECTOR_INT;
1555 for (; mode != VOIDmode ; mode = GET_MODE_WIDER_MODE (mode))
1556 if (GET_MODE_NUNITS (mode) == nunits
1557 && GET_MODE_INNER (mode) == innermode
1558 && targetm.vector_mode_supported_p (mode))
1561 /* For integers, try mapping it to a same-sized scalar mode. */
1562 if (mode == VOIDmode
1563 && GET_MODE_CLASS (innermode) == MODE_INT)
1564 mode = mode_for_size (nunits * GET_MODE_BITSIZE (innermode),
1567 if (mode == VOIDmode || !have_regs_of_mode[mode])
1568 TYPE_MODE (type) = BLKmode;
1570 TYPE_MODE (type) = mode;
1573 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1574 TYPE_SIZE_UNIT (type) = int_const_binop (MULT_EXPR,
1575 TYPE_SIZE_UNIT (innertype),
1577 TYPE_SIZE (type) = int_const_binop (MULT_EXPR, TYPE_SIZE (innertype),
1583 /* This is an incomplete type and so doesn't have a size. */
1584 TYPE_ALIGN (type) = 1;
1585 TYPE_USER_ALIGN (type) = 0;
1586 TYPE_MODE (type) = VOIDmode;
1590 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1591 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1592 /* A pointer might be MODE_PARTIAL_INT,
1593 but ptrdiff_t must be integral. */
1594 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1599 /* It's hard to see what the mode and size of a function ought to
1600 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1601 make it consistent with that. */
1602 TYPE_MODE (type) = mode_for_size (FUNCTION_BOUNDARY, MODE_INT, 0);
1603 TYPE_SIZE (type) = bitsize_int (FUNCTION_BOUNDARY);
1604 TYPE_SIZE_UNIT (type) = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
1608 case REFERENCE_TYPE:
1611 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1612 && reference_types_internal)
1613 ? Pmode : TYPE_MODE (type));
1615 int nbits = GET_MODE_BITSIZE (mode);
1617 TYPE_SIZE (type) = bitsize_int (nbits);
1618 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1619 TYPE_UNSIGNED (type) = 1;
1620 TYPE_PRECISION (type) = nbits;
1626 tree index = TYPE_DOMAIN (type);
1627 tree element = TREE_TYPE (type);
1629 build_pointer_type (element);
1631 /* We need to know both bounds in order to compute the size. */
1632 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1633 && TYPE_SIZE (element))
1635 tree ub = TYPE_MAX_VALUE (index);
1636 tree lb = TYPE_MIN_VALUE (index);
1640 /* The initial subtraction should happen in the original type so
1641 that (possible) negative values are handled appropriately. */
1642 length = size_binop (PLUS_EXPR, size_one_node,
1644 fold (build2 (MINUS_EXPR,
1648 /* Special handling for arrays of bits (for Chill). */
1649 element_size = TYPE_SIZE (element);
1650 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1651 && (integer_zerop (TYPE_MAX_VALUE (element))
1652 || integer_onep (TYPE_MAX_VALUE (element)))
1653 && host_integerp (TYPE_MIN_VALUE (element), 1))
1655 HOST_WIDE_INT maxvalue
1656 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1657 HOST_WIDE_INT minvalue
1658 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1660 if (maxvalue - minvalue == 1
1661 && (maxvalue == 1 || maxvalue == 0))
1662 element_size = integer_one_node;
1665 /* If neither bound is a constant and sizetype is signed, make
1666 sure the size is never negative. We should really do this
1667 if *either* bound is non-constant, but this is the best
1668 compromise between C and Ada. */
1669 if (!TYPE_UNSIGNED (sizetype)
1670 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
1671 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
1672 length = size_binop (MAX_EXPR, length, size_zero_node);
1674 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1675 convert (bitsizetype, length));
1677 /* If we know the size of the element, calculate the total
1678 size directly, rather than do some division thing below.
1679 This optimization helps Fortran assumed-size arrays
1680 (where the size of the array is determined at runtime)
1682 Note that we can't do this in the case where the size of
1683 the elements is one bit since TYPE_SIZE_UNIT cannot be
1684 set correctly in that case. */
1685 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1686 TYPE_SIZE_UNIT (type)
1687 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1690 /* Now round the alignment and size,
1691 using machine-dependent criteria if any. */
1693 #ifdef ROUND_TYPE_ALIGN
1695 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1697 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1699 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1700 TYPE_MODE (type) = BLKmode;
1701 if (TYPE_SIZE (type) != 0
1702 #ifdef MEMBER_TYPE_FORCES_BLK
1703 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1705 /* BLKmode elements force BLKmode aggregate;
1706 else extract/store fields may lose. */
1707 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1708 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1710 /* One-element arrays get the component type's mode. */
1711 if (simple_cst_equal (TYPE_SIZE (type),
1712 TYPE_SIZE (TREE_TYPE (type))))
1713 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1716 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1718 if (TYPE_MODE (type) != BLKmode
1719 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1720 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1721 && TYPE_MODE (type) != BLKmode)
1723 TYPE_NO_FORCE_BLK (type) = 1;
1724 TYPE_MODE (type) = BLKmode;
1732 case QUAL_UNION_TYPE:
1735 record_layout_info rli;
1737 /* Initialize the layout information. */
1738 rli = start_record_layout (type);
1740 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1741 in the reverse order in building the COND_EXPR that denotes
1742 its size. We reverse them again later. */
1743 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1744 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1746 /* Place all the fields. */
1747 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1748 place_field (rli, field);
1750 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1751 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1753 if (lang_adjust_rli)
1754 (*lang_adjust_rli) (rli);
1756 /* Finish laying out the record. */
1757 finish_record_layout (rli, /*free_p=*/true);
1761 case SET_TYPE: /* Used by Chill and Pascal. */
1762 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1763 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1767 #ifndef SET_WORD_SIZE
1768 #define SET_WORD_SIZE BITS_PER_WORD
1770 unsigned int alignment
1771 = set_alignment ? set_alignment : SET_WORD_SIZE;
1772 HOST_WIDE_INT size_in_bits
1773 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), 0)
1774 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0) + 1);
1775 HOST_WIDE_INT rounded_size
1776 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1778 if (rounded_size > (int) alignment)
1779 TYPE_MODE (type) = BLKmode;
1781 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1783 TYPE_SIZE (type) = bitsize_int (rounded_size);
1784 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1785 TYPE_ALIGN (type) = alignment;
1786 TYPE_USER_ALIGN (type) = 0;
1787 TYPE_PRECISION (type) = size_in_bits;
1792 /* The size may vary in different languages, so the language front end
1793 should fill in the size. */
1794 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1795 TYPE_USER_ALIGN (type) = 0;
1796 TYPE_MODE (type) = BLKmode;
1803 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1804 records and unions, finish_record_layout already called this
1806 if (TREE_CODE (type) != RECORD_TYPE
1807 && TREE_CODE (type) != UNION_TYPE
1808 && TREE_CODE (type) != QUAL_UNION_TYPE)
1809 finalize_type_size (type);
1811 /* If an alias set has been set for this aggregate when it was incomplete,
1812 force it into alias set 0.
1813 This is too conservative, but we cannot call record_component_aliases
1814 here because some frontends still change the aggregates after
1816 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1817 TYPE_ALIAS_SET (type) = 0;
1820 /* Create and return a type for signed integers of PRECISION bits. */
1823 make_signed_type (int precision)
1825 tree type = make_node (INTEGER_TYPE);
1827 TYPE_PRECISION (type) = precision;
1829 fixup_signed_type (type);
1833 /* Create and return a type for unsigned integers of PRECISION bits. */
1836 make_unsigned_type (int precision)
1838 tree type = make_node (INTEGER_TYPE);
1840 TYPE_PRECISION (type) = precision;
1842 fixup_unsigned_type (type);
1846 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1847 value to enable integer types to be created. */
1850 initialize_sizetypes (bool signed_p)
1852 tree t = make_node (INTEGER_TYPE);
1854 TYPE_MODE (t) = SImode;
1855 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1856 TYPE_USER_ALIGN (t) = 0;
1857 TYPE_IS_SIZETYPE (t) = 1;
1858 TYPE_UNSIGNED (t) = !signed_p;
1859 TYPE_SIZE (t) = build_int_cst (t, GET_MODE_BITSIZE (SImode), 0);
1860 TYPE_SIZE_UNIT (t) = build_int_cst (t, GET_MODE_SIZE (SImode), 0);
1861 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1862 TYPE_MIN_VALUE (t) = build_int_cst (t, 0, 0);
1864 /* 1000 avoids problems with possible overflow and is certainly
1865 larger than any size value we'd want to be storing. */
1866 TYPE_MAX_VALUE (t) = build_int_cst (t, 1000, 0);
1869 bitsizetype = build_distinct_type_copy (t);
1872 /* Make sizetype a version of TYPE, and initialize *sizetype
1873 accordingly. We do this by overwriting the stub sizetype and
1874 bitsizetype nodes created by initialize_sizetypes. This makes sure
1875 that (a) anything stubby about them no longer exists, (b) any
1876 INTEGER_CSTs created with such a type, remain valid. */
1879 set_sizetype (tree type)
1881 int oprecision = TYPE_PRECISION (type);
1882 /* The *bitsizetype types use a precision that avoids overflows when
1883 calculating signed sizes / offsets in bits. However, when
1884 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1886 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1887 2 * HOST_BITS_PER_WIDE_INT);
1892 if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (sizetype))
1895 t = build_distinct_type_copy (type);
1896 /* We do want to use sizetype's cache, as we will be replacing that
1898 TYPE_CACHED_VALUES (t) = TYPE_CACHED_VALUES (sizetype);
1899 TYPE_CACHED_VALUES_P (t) = TYPE_CACHED_VALUES_P (sizetype);
1900 TREE_TYPE (TYPE_CACHED_VALUES (t)) = type;
1901 TYPE_UID (t) = TYPE_UID (sizetype);
1902 TYPE_IS_SIZETYPE (t) = 1;
1904 /* Replace our original stub sizetype. */
1905 memcpy (sizetype, t, tree_size (sizetype));
1906 TYPE_MAIN_VARIANT (sizetype) = sizetype;
1908 t = make_node (INTEGER_TYPE);
1909 TYPE_NAME (t) = get_identifier ("bit_size_type");
1910 /* We do want to use bitsizetype's cache, as we will be replacing that
1912 TYPE_CACHED_VALUES (t) = TYPE_CACHED_VALUES (bitsizetype);
1913 TYPE_CACHED_VALUES_P (t) = TYPE_CACHED_VALUES_P (bitsizetype);
1914 TYPE_PRECISION (t) = precision;
1915 TYPE_UID (t) = TYPE_UID (bitsizetype);
1916 TYPE_IS_SIZETYPE (t) = 1;
1917 /* Replace our original stub bitsizetype. */
1918 memcpy (bitsizetype, t, tree_size (bitsizetype));
1920 if (TYPE_UNSIGNED (type))
1922 fixup_unsigned_type (bitsizetype);
1923 ssizetype = build_distinct_type_copy (make_signed_type (oprecision));
1924 TYPE_IS_SIZETYPE (ssizetype) = 1;
1925 sbitsizetype = build_distinct_type_copy (make_signed_type (precision));
1926 TYPE_IS_SIZETYPE (sbitsizetype) = 1;
1930 fixup_signed_type (bitsizetype);
1931 ssizetype = sizetype;
1932 sbitsizetype = bitsizetype;
1936 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1937 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1938 for TYPE, based on the PRECISION and whether or not the TYPE
1939 IS_UNSIGNED. PRECISION need not correspond to a width supported
1940 natively by the hardware; for example, on a machine with 8-bit,
1941 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1945 set_min_and_max_values_for_integral_type (tree type,
1954 min_value = build_int_cst (type, 0, 0);
1956 = build_int_cst (type, precision - HOST_BITS_PER_WIDE_INT >= 0
1957 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1958 precision - HOST_BITS_PER_WIDE_INT > 0
1959 ? ((unsigned HOST_WIDE_INT) ~0
1960 >> (HOST_BITS_PER_WIDE_INT
1961 - (precision - HOST_BITS_PER_WIDE_INT)))
1967 = build_int_cst (type,
1968 (precision - HOST_BITS_PER_WIDE_INT > 0
1969 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1970 (((HOST_WIDE_INT) (-1)
1971 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1972 ? precision - HOST_BITS_PER_WIDE_INT - 1
1975 = build_int_cst (type,
1976 (precision - HOST_BITS_PER_WIDE_INT > 0
1977 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1978 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1979 ? (((HOST_WIDE_INT) 1
1980 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1984 TYPE_MIN_VALUE (type) = min_value;
1985 TYPE_MAX_VALUE (type) = max_value;
1988 /* Set the extreme values of TYPE based on its precision in bits,
1989 then lay it out. Used when make_signed_type won't do
1990 because the tree code is not INTEGER_TYPE.
1991 E.g. for Pascal, when the -fsigned-char option is given. */
1994 fixup_signed_type (tree type)
1996 int precision = TYPE_PRECISION (type);
1998 /* We can not represent properly constants greater then
1999 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2000 as they are used by i386 vector extensions and friends. */
2001 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2002 precision = HOST_BITS_PER_WIDE_INT * 2;
2004 set_min_and_max_values_for_integral_type (type, precision,
2005 /*is_unsigned=*/false);
2007 /* Lay out the type: set its alignment, size, etc. */
2011 /* Set the extreme values of TYPE based on its precision in bits,
2012 then lay it out. This is used both in `make_unsigned_type'
2013 and for enumeral types. */
2016 fixup_unsigned_type (tree type)
2018 int precision = TYPE_PRECISION (type);
2020 /* We can not represent properly constants greater then
2021 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2022 as they are used by i386 vector extensions and friends. */
2023 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2024 precision = HOST_BITS_PER_WIDE_INT * 2;
2026 TYPE_UNSIGNED (type) = 1;
2028 set_min_and_max_values_for_integral_type (type, precision,
2029 /*is_unsigned=*/true);
2031 /* Lay out the type: set its alignment, size, etc. */
2035 /* Find the best machine mode to use when referencing a bit field of length
2036 BITSIZE bits starting at BITPOS.
2038 The underlying object is known to be aligned to a boundary of ALIGN bits.
2039 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2040 larger than LARGEST_MODE (usually SImode).
2042 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2043 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2044 mode meeting these conditions.
2046 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2047 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2048 all the conditions. */
2051 get_best_mode (int bitsize, int bitpos, unsigned int align,
2052 enum machine_mode largest_mode, int volatilep)
2054 enum machine_mode mode;
2055 unsigned int unit = 0;
2057 /* Find the narrowest integer mode that contains the bit field. */
2058 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2059 mode = GET_MODE_WIDER_MODE (mode))
2061 unit = GET_MODE_BITSIZE (mode);
2062 if ((bitpos % unit) + bitsize <= unit)
2066 if (mode == VOIDmode
2067 /* It is tempting to omit the following line
2068 if STRICT_ALIGNMENT is true.
2069 But that is incorrect, since if the bitfield uses part of 3 bytes
2070 and we use a 4-byte mode, we could get a spurious segv
2071 if the extra 4th byte is past the end of memory.
2072 (Though at least one Unix compiler ignores this problem:
2073 that on the Sequent 386 machine. */
2074 || MIN (unit, BIGGEST_ALIGNMENT) > align
2075 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2078 if (SLOW_BYTE_ACCESS && ! volatilep)
2080 enum machine_mode wide_mode = VOIDmode, tmode;
2082 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2083 tmode = GET_MODE_WIDER_MODE (tmode))
2085 unit = GET_MODE_BITSIZE (tmode);
2086 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2087 && unit <= BITS_PER_WORD
2088 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2089 && (largest_mode == VOIDmode
2090 || unit <= GET_MODE_BITSIZE (largest_mode)))
2094 if (wide_mode != VOIDmode)
2101 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2102 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2105 get_mode_bounds (enum machine_mode mode, int sign,
2106 enum machine_mode target_mode,
2107 rtx *mmin, rtx *mmax)
2109 unsigned size = GET_MODE_BITSIZE (mode);
2110 unsigned HOST_WIDE_INT min_val, max_val;
2112 if (size > HOST_BITS_PER_WIDE_INT)
2117 min_val = -((unsigned HOST_WIDE_INT) 1 << (size - 1));
2118 max_val = ((unsigned HOST_WIDE_INT) 1 << (size - 1)) - 1;
2123 max_val = ((unsigned HOST_WIDE_INT) 1 << (size - 1) << 1) - 1;
2126 *mmin = GEN_INT (trunc_int_for_mode (min_val, target_mode));
2127 *mmax = GEN_INT (trunc_int_for_mode (max_val, target_mode));
2130 #include "gt-stor-layout.h"