1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1996, 1998,
3 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
36 #include "langhooks.h"
38 /* Set to one when set_sizetype has been called. */
39 static int sizetype_set;
41 /* List of types created before set_sizetype has been called. We do not
42 make this a GGC root since we want these nodes to be reclaimed. */
43 static tree early_type_list;
45 /* Data type for the expressions representing sizes of data types.
46 It is the first integer type laid out. */
47 tree sizetype_tab[(int) TYPE_KIND_LAST];
49 /* If nonzero, this is an upper limit on alignment of structure fields.
50 The value is measured in bits. */
51 unsigned int maximum_field_alignment;
53 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
54 May be overridden by front-ends. */
55 unsigned int set_alignment = 0;
57 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
58 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
59 called only by a front end. */
60 static int reference_types_internal = 0;
62 static void finalize_record_size PARAMS ((record_layout_info));
63 static void finalize_type_size PARAMS ((tree));
64 static void place_union_field PARAMS ((record_layout_info, tree));
65 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
66 static int excess_unit_span PARAMS ((HOST_WIDE_INT, HOST_WIDE_INT,
67 HOST_WIDE_INT, HOST_WIDE_INT,
70 static unsigned int update_alignment_for_field
71 PARAMS ((record_layout_info, tree,
73 extern void debug_rli PARAMS ((record_layout_info));
75 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
77 static GTY(()) tree pending_sizes;
79 /* Nonzero means cannot safely call expand_expr now,
80 so put variable sizes onto `pending_sizes' instead. */
82 int immediate_size_expand;
84 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
88 internal_reference_types ()
90 reference_types_internal = 1;
93 /* Get a list of all the objects put on the pending sizes list. */
98 tree chain = pending_sizes;
101 /* Put each SAVE_EXPR into the current function. */
102 for (t = chain; t; t = TREE_CHAIN (t))
103 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
109 /* Return nonzero if EXPR is present on the pending sizes list. */
112 is_pending_size (expr)
117 for (t = pending_sizes; t; t = TREE_CHAIN (t))
118 if (TREE_VALUE (t) == expr)
123 /* Add EXPR to the pending sizes list. */
126 put_pending_size (expr)
129 /* Strip any simple arithmetic from EXPR to see if it has an underlying
131 expr = skip_simple_arithmetic (expr);
133 if (TREE_CODE (expr) == SAVE_EXPR)
134 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
137 /* Put a chain of objects into the pending sizes list, which must be
141 put_pending_sizes (chain)
147 pending_sizes = chain;
150 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
151 to serve as the actual size-expression for a type or decl. */
159 /* If the language-processor is to take responsibility for variable-sized
160 items (e.g., languages which have elaboration procedures like Ada),
161 just return SIZE unchanged. Likewise for self-referential sizes and
163 if (TREE_CONSTANT (size)
164 || (*lang_hooks.decls.global_bindings_p) () < 0
165 || contains_placeholder_p (size))
168 if (TREE_CODE (size) == MINUS_EXPR && integer_onep (TREE_OPERAND (size, 1)))
169 /* If this is the upper bound of a C array, leave the minus 1 outside
170 the SAVE_EXPR so it can be folded away. */
171 TREE_OPERAND (size, 0) = save = save_expr (TREE_OPERAND (size, 0));
173 size = save = save_expr (size);
175 /* If an array with a variable number of elements is declared, and
176 the elements require destruction, we will emit a cleanup for the
177 array. That cleanup is run both on normal exit from the block
178 and in the exception-handler for the block. Normally, when code
179 is used in both ordinary code and in an exception handler it is
180 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
181 not wish to do that here; the array-size is the same in both
183 if (TREE_CODE (save) == SAVE_EXPR)
184 SAVE_EXPR_PERSISTENT_P (save) = 1;
186 if ((*lang_hooks.decls.global_bindings_p) ())
188 if (TREE_CONSTANT (size))
189 error ("type size can't be explicitly evaluated");
191 error ("variable-size type declared outside of any function");
193 return size_one_node;
196 if (immediate_size_expand)
197 expand_expr (save, const0_rtx, VOIDmode, 0);
198 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
199 /* The front-end doesn't want us to keep a list of the expressions
200 that determine sizes for variable size objects. */
203 put_pending_size (save);
208 #ifndef MAX_FIXED_MODE_SIZE
209 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
212 /* Return the machine mode to use for a nonscalar of SIZE bits.
213 The mode must be in class CLASS, and have exactly that many bits.
214 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
218 mode_for_size (size, class, limit)
220 enum mode_class class;
223 enum machine_mode mode;
225 if (limit && size > MAX_FIXED_MODE_SIZE)
228 /* Get the first mode which has this size, in the specified class. */
229 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
230 mode = GET_MODE_WIDER_MODE (mode))
231 if (GET_MODE_BITSIZE (mode) == size)
237 /* Similar, except passed a tree node. */
240 mode_for_size_tree (size, class, limit)
242 enum mode_class class;
245 if (TREE_CODE (size) != INTEGER_CST
246 || TREE_OVERFLOW (size)
247 /* What we really want to say here is that the size can fit in a
248 host integer, but we know there's no way we'd find a mode for
249 this many bits, so there's no point in doing the precise test. */
250 || compare_tree_int (size, 1000) > 0)
253 return mode_for_size (tree_low_cst (size, 1), class, limit);
256 /* Similar, but never return BLKmode; return the narrowest mode that
257 contains at least the requested number of bits. */
260 smallest_mode_for_size (size, class)
262 enum mode_class class;
264 enum machine_mode mode;
266 /* Get the first mode which has at least this size, in the
268 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
269 mode = GET_MODE_WIDER_MODE (mode))
270 if (GET_MODE_BITSIZE (mode) >= size)
276 /* Find an integer mode of the exact same size, or BLKmode on failure. */
279 int_mode_for_mode (mode)
280 enum machine_mode mode;
282 switch (GET_MODE_CLASS (mode))
285 case MODE_PARTIAL_INT:
288 case MODE_COMPLEX_INT:
289 case MODE_COMPLEX_FLOAT:
291 case MODE_VECTOR_INT:
292 case MODE_VECTOR_FLOAT:
293 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
300 /* ... fall through ... */
310 /* Return the alignment of MODE. This will be bounded by 1 and
311 BIGGEST_ALIGNMENT. */
314 get_mode_alignment (mode)
315 enum machine_mode mode;
317 unsigned int alignment;
319 if (GET_MODE_CLASS (mode) == MODE_COMPLEX_FLOAT
320 || GET_MODE_CLASS (mode) == MODE_COMPLEX_INT)
321 alignment = GET_MODE_UNIT_SIZE (mode);
323 alignment = GET_MODE_SIZE (mode);
325 /* Extract the LSB of the size. */
326 alignment = alignment & -alignment;
327 alignment *= BITS_PER_UNIT;
329 alignment = MIN (BIGGEST_ALIGNMENT, MAX (1, alignment));
333 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
334 This can only be applied to objects of a sizetype. */
337 round_up (value, divisor)
341 tree arg = size_int_type (divisor, TREE_TYPE (value));
343 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
346 /* Likewise, but round down. */
349 round_down (value, divisor)
353 tree arg = size_int_type (divisor, TREE_TYPE (value));
355 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
358 /* Subroutine of layout_decl: Force alignment required for the data type.
359 But if the decl itself wants greater alignment, don't override that. */
362 do_type_align (tree type, tree decl)
364 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
366 DECL_ALIGN (decl) = TYPE_ALIGN (type);
367 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
371 /* Set the size, mode and alignment of a ..._DECL node.
372 TYPE_DECL does need this for C++.
373 Note that LABEL_DECL and CONST_DECL nodes do not need this,
374 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
375 Don't call layout_decl for them.
377 KNOWN_ALIGN is the amount of alignment we can assume this
378 decl has with no special effort. It is relevant only for FIELD_DECLs
379 and depends on the previous fields.
380 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
381 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
382 the record will be aligned to suit. */
385 layout_decl (decl, known_align)
387 unsigned int known_align;
389 tree type = TREE_TYPE (decl);
390 enum tree_code code = TREE_CODE (decl);
393 if (code == CONST_DECL)
395 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
396 && code != TYPE_DECL && code != FIELD_DECL)
399 rtl = DECL_RTL_IF_SET (decl);
401 if (type == error_mark_node)
402 type = void_type_node;
404 /* Usually the size and mode come from the data type without change,
405 however, the front-end may set the explicit width of the field, so its
406 size may not be the same as the size of its type. This happens with
407 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
408 also happens with other fields. For example, the C++ front-end creates
409 zero-sized fields corresponding to empty base classes, and depends on
410 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
411 size in bytes from the size in bits. If we have already set the mode,
412 don't set it again since we can be called twice for FIELD_DECLs. */
414 TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
415 if (DECL_MODE (decl) == VOIDmode)
416 DECL_MODE (decl) = TYPE_MODE (type);
418 if (DECL_SIZE (decl) == 0)
420 DECL_SIZE (decl) = TYPE_SIZE (type);
421 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
423 else if (DECL_SIZE_UNIT (decl) == 0)
424 DECL_SIZE_UNIT (decl)
425 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
428 if (code != FIELD_DECL)
429 /* For non-fields, update the alignment from the type. */
430 do_type_align (type, decl);
432 /* For fields, it's a bit more complicated... */
434 if (DECL_BIT_FIELD (decl))
436 DECL_BIT_FIELD_TYPE (decl) = type;
438 /* A zero-length bit-field affects the alignment of the next
440 if (integer_zerop (DECL_SIZE (decl))
441 && ! DECL_PACKED (decl)
442 && ! (*targetm.ms_bitfield_layout_p) (DECL_FIELD_CONTEXT (decl)))
444 #ifdef PCC_BITFIELD_TYPE_MATTERS
445 if (PCC_BITFIELD_TYPE_MATTERS)
446 do_type_align (type, decl);
450 #ifdef EMPTY_FIELD_BOUNDARY
451 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
453 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
454 DECL_USER_ALIGN (decl) = 0;
460 /* See if we can use an ordinary integer mode for a bit-field.
461 Conditions are: a fixed size that is correct for another mode
462 and occupying a complete byte or bytes on proper boundary. */
463 if (TYPE_SIZE (type) != 0
464 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
465 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
467 enum machine_mode xmode
468 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
470 if (xmode != BLKmode && known_align >= GET_MODE_ALIGNMENT (xmode))
472 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
474 DECL_MODE (decl) = xmode;
475 DECL_BIT_FIELD (decl) = 0;
479 /* Turn off DECL_BIT_FIELD if we won't need it set. */
480 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
481 && known_align >= TYPE_ALIGN (type)
482 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
483 DECL_BIT_FIELD (decl) = 0;
485 else if (DECL_PACKED (decl) && DECL_USER_ALIGN (decl))
486 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
487 round up; we'll reduce it again below. */;
489 do_type_align (type, decl);
491 /* If the field is of variable size, we can't misalign it since we
492 have no way to make a temporary to align the result. But this
493 isn't an issue if the decl is not addressable. Likewise if it
494 is of unknown size. */
495 if (DECL_PACKED (decl)
496 && !DECL_USER_ALIGN (decl)
497 && (DECL_NONADDRESSABLE_P (decl)
498 || DECL_SIZE_UNIT (decl) == 0
499 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
500 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
502 /* Should this be controlled by DECL_USER_ALIGN, too? */
503 if (maximum_field_alignment != 0)
504 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
505 if (! DECL_USER_ALIGN (decl))
507 /* Some targets (i.e. i386, VMS) limit struct field alignment
508 to a lower boundary than alignment of variables unless
509 it was overridden by attribute aligned. */
510 #ifdef BIGGEST_FIELD_ALIGNMENT
512 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
514 #ifdef ADJUST_FIELD_ALIGN
515 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
520 /* Evaluate nonconstant size only once, either now or as soon as safe. */
521 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
522 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
523 if (DECL_SIZE_UNIT (decl) != 0
524 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
525 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
527 /* If requested, warn about definitions of large data objects. */
529 && (code == VAR_DECL || code == PARM_DECL)
530 && ! DECL_EXTERNAL (decl))
532 tree size = DECL_SIZE_UNIT (decl);
534 if (size != 0 && TREE_CODE (size) == INTEGER_CST
535 && compare_tree_int (size, larger_than_size) > 0)
537 int size_as_int = TREE_INT_CST_LOW (size);
539 if (compare_tree_int (size, size_as_int) == 0)
540 warning_with_decl (decl, "size of `%s' is %d bytes", size_as_int);
542 warning_with_decl (decl, "size of `%s' is larger than %d bytes",
547 /* If the RTL was already set, update its mode and mem attributes. */
550 PUT_MODE (rtl, DECL_MODE (decl));
551 SET_DECL_RTL (decl, 0);
552 set_mem_attributes (rtl, decl, 1);
553 SET_DECL_RTL (decl, rtl);
557 /* Hook for a front-end function that can modify the record layout as needed
558 immediately before it is finalized. */
560 void (*lang_adjust_rli) PARAMS ((record_layout_info)) = 0;
563 set_lang_adjust_rli (f)
564 void (*f) PARAMS ((record_layout_info));
569 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
570 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
571 is to be passed to all other layout functions for this record. It is the
572 responsibility of the caller to call `free' for the storage returned.
573 Note that garbage collection is not permitted until we finish laying
577 start_record_layout (t)
580 record_layout_info rli
581 = (record_layout_info) xmalloc (sizeof (struct record_layout_info_s));
585 /* If the type has a minimum specified alignment (via an attribute
586 declaration, for example) use it -- otherwise, start with a
587 one-byte alignment. */
588 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
589 rli->unpacked_align = rli->record_align;
590 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
592 #ifdef STRUCTURE_SIZE_BOUNDARY
593 /* Packed structures don't need to have minimum size. */
594 if (! TYPE_PACKED (t))
595 rli->record_align = MAX (rli->record_align, (unsigned) STRUCTURE_SIZE_BOUNDARY);
598 rli->offset = size_zero_node;
599 rli->bitpos = bitsize_zero_node;
601 rli->pending_statics = 0;
602 rli->packed_maybe_necessary = 0;
607 /* These four routines perform computations that convert between
608 the offset/bitpos forms and byte and bit offsets. */
611 bit_from_pos (offset, bitpos)
614 return size_binop (PLUS_EXPR, bitpos,
615 size_binop (MULT_EXPR, convert (bitsizetype, offset),
620 byte_from_pos (offset, bitpos)
623 return size_binop (PLUS_EXPR, offset,
625 size_binop (TRUNC_DIV_EXPR, bitpos,
626 bitsize_unit_node)));
630 pos_from_bit (poffset, pbitpos, off_align, pos)
631 tree *poffset, *pbitpos;
632 unsigned int off_align;
635 *poffset = size_binop (MULT_EXPR,
637 size_binop (FLOOR_DIV_EXPR, pos,
638 bitsize_int (off_align))),
639 size_int (off_align / BITS_PER_UNIT));
640 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
643 /* Given a pointer to bit and byte offsets and an offset alignment,
644 normalize the offsets so they are within the alignment. */
647 normalize_offset (poffset, pbitpos, off_align)
648 tree *poffset, *pbitpos;
649 unsigned int off_align;
651 /* If the bit position is now larger than it should be, adjust it
653 if (compare_tree_int (*pbitpos, off_align) >= 0)
655 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
656 bitsize_int (off_align));
659 = size_binop (PLUS_EXPR, *poffset,
660 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
661 size_int (off_align / BITS_PER_UNIT)));
664 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
668 /* Print debugging information about the information in RLI. */
672 record_layout_info rli;
674 print_node_brief (stderr, "type", rli->t, 0);
675 print_node_brief (stderr, "\noffset", rli->offset, 0);
676 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
678 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
679 rli->record_align, rli->unpacked_align,
681 if (rli->packed_maybe_necessary)
682 fprintf (stderr, "packed may be necessary\n");
684 if (rli->pending_statics)
686 fprintf (stderr, "pending statics:\n");
687 debug_tree (rli->pending_statics);
691 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
692 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
696 record_layout_info rli;
698 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
701 /* Returns the size in bytes allocated so far. */
704 rli_size_unit_so_far (rli)
705 record_layout_info rli;
707 return byte_from_pos (rli->offset, rli->bitpos);
710 /* Returns the size in bits allocated so far. */
713 rli_size_so_far (rli)
714 record_layout_info rli;
716 return bit_from_pos (rli->offset, rli->bitpos);
719 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
720 the next available location is given by KNOWN_ALIGN. Update the
721 variable alignment fields in RLI, and return the alignment to give
725 update_alignment_for_field (rli, field, known_align)
726 record_layout_info rli;
728 unsigned int known_align;
730 /* The alignment required for FIELD. */
731 unsigned int desired_align;
732 /* The type of this field. */
733 tree type = TREE_TYPE (field);
734 /* True if the field was explicitly aligned by the user. */
738 /* Lay out the field so we know what alignment it needs. */
739 layout_decl (field, known_align);
740 desired_align = DECL_ALIGN (field);
741 user_align = DECL_USER_ALIGN (field);
743 is_bitfield = (type != error_mark_node
744 && DECL_BIT_FIELD_TYPE (field)
745 && ! integer_zerop (TYPE_SIZE (type)));
747 /* Record must have at least as much alignment as any field.
748 Otherwise, the alignment of the field within the record is
750 if (is_bitfield && (* targetm.ms_bitfield_layout_p) (rli->t))
752 /* Here, the alignment of the underlying type of a bitfield can
753 affect the alignment of a record; even a zero-sized field
754 can do this. The alignment should be to the alignment of
755 the type, except that for zero-size bitfields this only
756 applies if there was an immediately prior, nonzero-size
757 bitfield. (That's the way it is, experimentally.) */
758 if (! integer_zerop (DECL_SIZE (field))
759 ? ! DECL_PACKED (field)
761 && DECL_BIT_FIELD_TYPE (rli->prev_field)
762 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
764 unsigned int type_align = TYPE_ALIGN (type);
765 type_align = MAX (type_align, desired_align);
766 if (maximum_field_alignment != 0)
767 type_align = MIN (type_align, maximum_field_alignment);
768 rli->record_align = MAX (rli->record_align, type_align);
769 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
772 #ifdef PCC_BITFIELD_TYPE_MATTERS
773 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
775 /* Named bit-fields cause the entire structure to have the
776 alignment implied by their type. */
777 if (DECL_NAME (field) != 0)
779 unsigned int type_align = TYPE_ALIGN (type);
781 #ifdef ADJUST_FIELD_ALIGN
782 if (! TYPE_USER_ALIGN (type))
783 type_align = ADJUST_FIELD_ALIGN (field, type_align);
786 if (maximum_field_alignment != 0)
787 type_align = MIN (type_align, maximum_field_alignment);
788 else if (DECL_PACKED (field))
789 type_align = MIN (type_align, BITS_PER_UNIT);
791 /* The alignment of the record is increased to the maximum
792 of the current alignment, the alignment indicated on the
793 field (i.e., the alignment specified by an __aligned__
794 attribute), and the alignment indicated by the type of
796 rli->record_align = MAX (rli->record_align, desired_align);
797 rli->record_align = MAX (rli->record_align, type_align);
800 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
801 user_align |= TYPE_USER_ALIGN (type);
807 rli->record_align = MAX (rli->record_align, desired_align);
808 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
811 TYPE_USER_ALIGN (rli->t) |= user_align;
813 return desired_align;
816 /* Called from place_field to handle unions. */
819 place_union_field (rli, field)
820 record_layout_info rli;
823 update_alignment_for_field (rli, field, /*known_align=*/0);
825 DECL_FIELD_OFFSET (field) = size_zero_node;
826 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
827 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
829 /* We assume the union's size will be a multiple of a byte so we don't
830 bother with BITPOS. */
831 if (TREE_CODE (rli->t) == UNION_TYPE)
832 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
833 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
834 rli->offset = fold (build (COND_EXPR, sizetype,
835 DECL_QUALIFIER (field),
836 DECL_SIZE_UNIT (field), rli->offset));
839 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
840 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
841 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
842 units of alignment than the underlying TYPE. */
844 excess_unit_span (byte_offset, bit_offset, size, align, type)
845 HOST_WIDE_INT byte_offset, bit_offset, size, align;
848 /* Note that the calculation of OFFSET might overflow; we calculate it so
849 that we still get the right result as long as ALIGN is a power of two. */
850 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
852 offset = offset % align;
853 return ((offset + size + align - 1) / align
854 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
859 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
860 is a FIELD_DECL to be added after those fields already present in
861 T. (FIELD is not actually added to the TYPE_FIELDS list here;
862 callers that desire that behavior must manually perform that step.) */
865 place_field (rli, field)
866 record_layout_info rli;
869 /* The alignment required for FIELD. */
870 unsigned int desired_align;
871 /* The alignment FIELD would have if we just dropped it into the
872 record as it presently stands. */
873 unsigned int known_align;
874 unsigned int actual_align;
875 /* The type of this field. */
876 tree type = TREE_TYPE (field);
878 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
881 /* If FIELD is static, then treat it like a separate variable, not
882 really like a structure field. If it is a FUNCTION_DECL, it's a
883 method. In both cases, all we do is lay out the decl, and we do
884 it *after* the record is laid out. */
885 if (TREE_CODE (field) == VAR_DECL)
887 rli->pending_statics = tree_cons (NULL_TREE, field,
888 rli->pending_statics);
892 /* Enumerators and enum types which are local to this class need not
893 be laid out. Likewise for initialized constant fields. */
894 else if (TREE_CODE (field) != FIELD_DECL)
897 /* Unions are laid out very differently than records, so split
898 that code off to another function. */
899 else if (TREE_CODE (rli->t) != RECORD_TYPE)
901 place_union_field (rli, field);
905 /* Work out the known alignment so far. Note that A & (-A) is the
906 value of the least-significant bit in A that is one. */
907 if (! integer_zerop (rli->bitpos))
908 known_align = (tree_low_cst (rli->bitpos, 1)
909 & - tree_low_cst (rli->bitpos, 1));
910 else if (integer_zerop (rli->offset))
911 known_align = BIGGEST_ALIGNMENT;
912 else if (host_integerp (rli->offset, 1))
913 known_align = (BITS_PER_UNIT
914 * (tree_low_cst (rli->offset, 1)
915 & - tree_low_cst (rli->offset, 1)));
917 known_align = rli->offset_align;
919 desired_align = update_alignment_for_field (rli, field, known_align);
921 if (warn_packed && DECL_PACKED (field))
923 if (known_align >= TYPE_ALIGN (type))
925 if (TYPE_ALIGN (type) > desired_align)
927 if (STRICT_ALIGNMENT)
928 warning_with_decl (field, "packed attribute causes inefficient alignment for `%s'");
930 warning_with_decl (field, "packed attribute is unnecessary for `%s'");
934 rli->packed_maybe_necessary = 1;
937 /* Does this field automatically have alignment it needs by virtue
938 of the fields that precede it and the record's own alignment? */
939 if (known_align < desired_align)
941 /* No, we need to skip space before this field.
942 Bump the cumulative size to multiple of field alignment. */
945 warning_with_decl (field, "padding struct to align `%s'");
947 /* If the alignment is still within offset_align, just align
949 if (desired_align < rli->offset_align)
950 rli->bitpos = round_up (rli->bitpos, desired_align);
953 /* First adjust OFFSET by the partial bits, then align. */
955 = size_binop (PLUS_EXPR, rli->offset,
957 size_binop (CEIL_DIV_EXPR, rli->bitpos,
958 bitsize_unit_node)));
959 rli->bitpos = bitsize_zero_node;
961 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
964 if (! TREE_CONSTANT (rli->offset))
965 rli->offset_align = desired_align;
969 /* Handle compatibility with PCC. Note that if the record has any
970 variable-sized fields, we need not worry about compatibility. */
971 #ifdef PCC_BITFIELD_TYPE_MATTERS
972 if (PCC_BITFIELD_TYPE_MATTERS
973 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
974 && TREE_CODE (field) == FIELD_DECL
975 && type != error_mark_node
976 && DECL_BIT_FIELD (field)
977 && ! DECL_PACKED (field)
978 && maximum_field_alignment == 0
979 && ! integer_zerop (DECL_SIZE (field))
980 && host_integerp (DECL_SIZE (field), 1)
981 && host_integerp (rli->offset, 1)
982 && host_integerp (TYPE_SIZE (type), 1))
984 unsigned int type_align = TYPE_ALIGN (type);
985 tree dsize = DECL_SIZE (field);
986 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
987 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
988 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
990 #ifdef ADJUST_FIELD_ALIGN
991 if (! TYPE_USER_ALIGN (type))
992 type_align = ADJUST_FIELD_ALIGN (field, type_align);
995 /* A bit field may not span more units of alignment of its type
996 than its type itself. Advance to next boundary if necessary. */
997 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
998 rli->bitpos = round_up (rli->bitpos, type_align);
1000 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
1004 #ifdef BITFIELD_NBYTES_LIMITED
1005 if (BITFIELD_NBYTES_LIMITED
1006 && ! (* targetm.ms_bitfield_layout_p) (rli->t)
1007 && TREE_CODE (field) == FIELD_DECL
1008 && type != error_mark_node
1009 && DECL_BIT_FIELD_TYPE (field)
1010 && ! DECL_PACKED (field)
1011 && ! integer_zerop (DECL_SIZE (field))
1012 && host_integerp (DECL_SIZE (field), 1)
1013 && host_integerp (rli->offset, 1)
1014 && host_integerp (TYPE_SIZE (type), 1))
1016 unsigned int type_align = TYPE_ALIGN (type);
1017 tree dsize = DECL_SIZE (field);
1018 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
1019 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
1020 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
1022 #ifdef ADJUST_FIELD_ALIGN
1023 if (! TYPE_USER_ALIGN (type))
1024 type_align = ADJUST_FIELD_ALIGN (field, type_align);
1027 if (maximum_field_alignment != 0)
1028 type_align = MIN (type_align, maximum_field_alignment);
1029 /* ??? This test is opposite the test in the containing if
1030 statement, so this code is unreachable currently. */
1031 else if (DECL_PACKED (field))
1032 type_align = MIN (type_align, BITS_PER_UNIT);
1034 /* A bit field may not span the unit of alignment of its type.
1035 Advance to next boundary if necessary. */
1036 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
1037 rli->bitpos = round_up (rli->bitpos, type_align);
1039 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
1043 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1045 When a bit field is inserted into a packed record, the whole
1046 size of the underlying type is used by one or more same-size
1047 adjacent bitfields. (That is, if its long:3, 32 bits is
1048 used in the record, and any additional adjacent long bitfields are
1049 packed into the same chunk of 32 bits. However, if the size
1050 changes, a new field of that size is allocated.) In an unpacked
1051 record, this is the same as using alignment, but not equivalent
1054 Note: for compatibility, we use the type size, not the type alignment
1055 to determine alignment, since that matches the documentation */
1057 if ((* targetm.ms_bitfield_layout_p) (rli->t)
1058 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1059 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1061 /* At this point, either the prior or current are bitfields,
1062 (possibly both), and we're dealing with MS packing. */
1063 tree prev_saved = rli->prev_field;
1065 /* Is the prior field a bitfield? If so, handle "runs" of same
1066 type size fields. */
1067 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1069 /* If both are bitfields, nonzero, and the same size, this is
1070 the middle of a run. Zero declared size fields are special
1071 and handled as "end of run". (Note: it's nonzero declared
1072 size, but equal type sizes!) (Since we know that both
1073 the current and previous fields are bitfields by the
1074 time we check it, DECL_SIZE must be present for both.) */
1075 if (DECL_BIT_FIELD_TYPE (field)
1076 && !integer_zerop (DECL_SIZE (field))
1077 && !integer_zerop (DECL_SIZE (rli->prev_field))
1078 && host_integerp (DECL_SIZE (rli->prev_field), 0)
1079 && host_integerp (TYPE_SIZE (type), 0)
1080 && simple_cst_equal (TYPE_SIZE (type),
1081 TYPE_SIZE (TREE_TYPE (rli->prev_field))))
1083 /* We're in the middle of a run of equal type size fields; make
1084 sure we realign if we run out of bits. (Not decl size,
1086 HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 0);
1088 if (rli->remaining_in_alignment < bitsize)
1090 /* out of bits; bump up to next 'word'. */
1091 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1093 = size_binop (PLUS_EXPR, TYPE_SIZE (type),
1094 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1095 rli->prev_field = field;
1096 rli->remaining_in_alignment
1097 = tree_low_cst (TYPE_SIZE (type), 0);
1100 rli->remaining_in_alignment -= bitsize;
1104 /* End of a run: if leaving a run of bitfields of the same type
1105 size, we have to "use up" the rest of the bits of the type
1108 Compute the new position as the sum of the size for the prior
1109 type and where we first started working on that type.
1110 Note: since the beginning of the field was aligned then
1111 of course the end will be too. No round needed. */
1113 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1115 tree type_size = TYPE_SIZE (TREE_TYPE (rli->prev_field));
1118 = size_binop (PLUS_EXPR, type_size,
1119 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1122 /* We "use up" size zero fields; the code below should behave
1123 as if the prior field was not a bitfield. */
1126 /* Cause a new bitfield to be captured, either this time (if
1127 currently a bitfield) or next time we see one. */
1128 if (!DECL_BIT_FIELD_TYPE(field)
1129 || integer_zerop (DECL_SIZE (field)))
1130 rli->prev_field = NULL;
1133 normalize_rli (rli);
1136 /* If we're starting a new run of same size type bitfields
1137 (or a run of non-bitfields), set up the "first of the run"
1140 That is, if the current field is not a bitfield, or if there
1141 was a prior bitfield the type sizes differ, or if there wasn't
1142 a prior bitfield the size of the current field is nonzero.
1144 Note: we must be sure to test ONLY the type size if there was
1145 a prior bitfield and ONLY for the current field being zero if
1148 if (!DECL_BIT_FIELD_TYPE (field)
1149 || ( prev_saved != NULL
1150 ? !simple_cst_equal (TYPE_SIZE (type),
1151 TYPE_SIZE (TREE_TYPE (prev_saved)))
1152 : !integer_zerop (DECL_SIZE (field)) ))
1154 /* Never smaller than a byte for compatibility. */
1155 unsigned int type_align = BITS_PER_UNIT;
1157 /* (When not a bitfield), we could be seeing a flex array (with
1158 no DECL_SIZE). Since we won't be using remaining_in_alignment
1159 until we see a bitfield (and come by here again) we just skip
1161 if (DECL_SIZE (field) != NULL
1162 && host_integerp (TYPE_SIZE (TREE_TYPE (field)), 0)
1163 && host_integerp (DECL_SIZE (field), 0))
1164 rli->remaining_in_alignment
1165 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field)), 0)
1166 - tree_low_cst (DECL_SIZE (field), 0);
1168 /* Now align (conventionally) for the new type. */
1169 if (!DECL_PACKED(field))
1170 type_align = MAX(TYPE_ALIGN (type), type_align);
1173 && DECL_BIT_FIELD_TYPE (prev_saved)
1174 /* If the previous bit-field is zero-sized, we've already
1175 accounted for its alignment needs (or ignored it, if
1176 appropriate) while placing it. */
1177 && ! integer_zerop (DECL_SIZE (prev_saved)))
1178 type_align = MAX (type_align,
1179 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1181 if (maximum_field_alignment != 0)
1182 type_align = MIN (type_align, maximum_field_alignment);
1184 rli->bitpos = round_up (rli->bitpos, type_align);
1186 /* If we really aligned, don't allow subsequent bitfields
1188 rli->prev_field = NULL;
1192 /* Offset so far becomes the position of this field after normalizing. */
1193 normalize_rli (rli);
1194 DECL_FIELD_OFFSET (field) = rli->offset;
1195 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1196 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1198 /* If this field ended up more aligned than we thought it would be (we
1199 approximate this by seeing if its position changed), lay out the field
1200 again; perhaps we can use an integral mode for it now. */
1201 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1202 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1203 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1204 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1205 actual_align = BIGGEST_ALIGNMENT;
1206 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1207 actual_align = (BITS_PER_UNIT
1208 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1209 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1211 actual_align = DECL_OFFSET_ALIGN (field);
1213 if (known_align != actual_align)
1214 layout_decl (field, actual_align);
1216 /* Only the MS bitfields use this. */
1217 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1218 rli->prev_field = field;
1220 /* Now add size of this field to the size of the record. If the size is
1221 not constant, treat the field as being a multiple of bytes and just
1222 adjust the offset, resetting the bit position. Otherwise, apportion the
1223 size amongst the bit position and offset. First handle the case of an
1224 unspecified size, which can happen when we have an invalid nested struct
1225 definition, such as struct j { struct j { int i; } }. The error message
1226 is printed in finish_struct. */
1227 if (DECL_SIZE (field) == 0)
1229 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1230 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1233 = size_binop (PLUS_EXPR, rli->offset,
1235 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1236 bitsize_unit_node)));
1238 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1239 rli->bitpos = bitsize_zero_node;
1240 rli->offset_align = MIN (rli->offset_align, desired_align);
1244 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1245 normalize_rli (rli);
1249 /* Assuming that all the fields have been laid out, this function uses
1250 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1251 indicated by RLI. */
1254 finalize_record_size (rli)
1255 record_layout_info rli;
1257 tree unpadded_size, unpadded_size_unit;
1259 /* Now we want just byte and bit offsets, so set the offset alignment
1260 to be a byte and then normalize. */
1261 rli->offset_align = BITS_PER_UNIT;
1262 normalize_rli (rli);
1264 /* Determine the desired alignment. */
1265 #ifdef ROUND_TYPE_ALIGN
1266 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1269 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1272 /* Compute the size so far. Be sure to allow for extra bits in the
1273 size in bytes. We have guaranteed above that it will be no more
1274 than a single byte. */
1275 unpadded_size = rli_size_so_far (rli);
1276 unpadded_size_unit = rli_size_unit_so_far (rli);
1277 if (! integer_zerop (rli->bitpos))
1279 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1281 /* Round the size up to be a multiple of the required alignment */
1282 #ifdef ROUND_TYPE_SIZE
1283 TYPE_SIZE (rli->t) = ROUND_TYPE_SIZE (rli->t, unpadded_size,
1284 TYPE_ALIGN (rli->t));
1285 TYPE_SIZE_UNIT (rli->t)
1286 = ROUND_TYPE_SIZE_UNIT (rli->t, unpadded_size_unit,
1287 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1289 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1290 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1291 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1294 if (warn_padded && TREE_CONSTANT (unpadded_size)
1295 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1296 warning ("padding struct size to alignment boundary");
1298 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1299 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1300 && TREE_CONSTANT (unpadded_size))
1304 #ifdef ROUND_TYPE_ALIGN
1306 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1308 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1311 #ifdef ROUND_TYPE_SIZE
1312 unpacked_size = ROUND_TYPE_SIZE (rli->t, TYPE_SIZE (rli->t),
1313 rli->unpacked_align);
1315 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1318 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1320 TYPE_PACKED (rli->t) = 0;
1322 if (TYPE_NAME (rli->t))
1326 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1327 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1329 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1331 if (STRICT_ALIGNMENT)
1332 warning ("packed attribute causes inefficient alignment for `%s'", name);
1334 warning ("packed attribute is unnecessary for `%s'", name);
1338 if (STRICT_ALIGNMENT)
1339 warning ("packed attribute causes inefficient alignment");
1341 warning ("packed attribute is unnecessary");
1347 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1350 compute_record_mode (type)
1354 enum machine_mode mode = VOIDmode;
1356 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1357 However, if possible, we use a mode that fits in a register
1358 instead, in order to allow for better optimization down the
1360 TYPE_MODE (type) = BLKmode;
1362 if (! host_integerp (TYPE_SIZE (type), 1))
1365 /* A record which has any BLKmode members must itself be
1366 BLKmode; it can't go in a register. Unless the member is
1367 BLKmode only because it isn't aligned. */
1368 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1370 unsigned HOST_WIDE_INT bitpos;
1372 if (TREE_CODE (field) != FIELD_DECL)
1375 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1376 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1377 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
1378 || ! host_integerp (bit_position (field), 1)
1379 || DECL_SIZE (field) == 0
1380 || ! host_integerp (DECL_SIZE (field), 1))
1383 bitpos = int_bit_position (field);
1385 /* Must be BLKmode if any field crosses a word boundary,
1386 since extract_bit_field can't handle that in registers. */
1387 if (bitpos / BITS_PER_WORD
1388 != ((tree_low_cst (DECL_SIZE (field), 1) + bitpos - 1)
1390 /* But there is no problem if the field is entire words
1391 or bigger than a word. */
1392 && ! (tree_low_cst (DECL_SIZE (field), 1) % BITS_PER_WORD == 0
1393 || compare_tree_int (DECL_SIZE (field), BITS_PER_WORD) > 0))
1396 /* If this field is the whole struct, remember its mode so
1397 that, say, we can put a double in a class into a DF
1398 register instead of forcing it to live in the stack. */
1399 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1400 mode = DECL_MODE (field);
1402 #ifdef MEMBER_TYPE_FORCES_BLK
1403 /* With some targets, eg. c4x, it is sub-optimal
1404 to access an aligned BLKmode structure as a scalar. */
1406 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1408 #endif /* MEMBER_TYPE_FORCES_BLK */
1411 /* If we only have one real field; use its mode. This only applies to
1412 RECORD_TYPE. This does not apply to unions. */
1413 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1414 TYPE_MODE (type) = mode;
1416 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1418 /* If structure's known alignment is less than what the scalar
1419 mode would need, and it matters, then stick with BLKmode. */
1420 if (TYPE_MODE (type) != BLKmode
1422 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1423 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1425 /* If this is the only reason this type is BLKmode, then
1426 don't force containing types to be BLKmode. */
1427 TYPE_NO_FORCE_BLK (type) = 1;
1428 TYPE_MODE (type) = BLKmode;
1432 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1436 finalize_type_size (type)
1439 /* Normally, use the alignment corresponding to the mode chosen.
1440 However, where strict alignment is not required, avoid
1441 over-aligning structures, since most compilers do not do this
1444 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1445 && (STRICT_ALIGNMENT
1446 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1447 && TREE_CODE (type) != QUAL_UNION_TYPE
1448 && TREE_CODE (type) != ARRAY_TYPE)))
1450 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1451 TYPE_USER_ALIGN (type) = 0;
1454 /* Do machine-dependent extra alignment. */
1455 #ifdef ROUND_TYPE_ALIGN
1457 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1460 /* If we failed to find a simple way to calculate the unit size
1461 of the type, find it by division. */
1462 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1463 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1464 result will fit in sizetype. We will get more efficient code using
1465 sizetype, so we force a conversion. */
1466 TYPE_SIZE_UNIT (type)
1467 = convert (sizetype,
1468 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1469 bitsize_unit_node));
1471 if (TYPE_SIZE (type) != 0)
1473 #ifdef ROUND_TYPE_SIZE
1475 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1476 TYPE_SIZE_UNIT (type)
1477 = ROUND_TYPE_SIZE_UNIT (type, TYPE_SIZE_UNIT (type),
1478 TYPE_ALIGN (type) / BITS_PER_UNIT);
1480 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1481 TYPE_SIZE_UNIT (type)
1482 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1486 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1487 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1488 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1489 if (TYPE_SIZE_UNIT (type) != 0
1490 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1491 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1493 /* Also layout any other variants of the type. */
1494 if (TYPE_NEXT_VARIANT (type)
1495 || type != TYPE_MAIN_VARIANT (type))
1498 /* Record layout info of this variant. */
1499 tree size = TYPE_SIZE (type);
1500 tree size_unit = TYPE_SIZE_UNIT (type);
1501 unsigned int align = TYPE_ALIGN (type);
1502 unsigned int user_align = TYPE_USER_ALIGN (type);
1503 enum machine_mode mode = TYPE_MODE (type);
1505 /* Copy it into all variants. */
1506 for (variant = TYPE_MAIN_VARIANT (type);
1508 variant = TYPE_NEXT_VARIANT (variant))
1510 TYPE_SIZE (variant) = size;
1511 TYPE_SIZE_UNIT (variant) = size_unit;
1512 TYPE_ALIGN (variant) = align;
1513 TYPE_USER_ALIGN (variant) = user_align;
1514 TYPE_MODE (variant) = mode;
1519 /* Do all of the work required to layout the type indicated by RLI,
1520 once the fields have been laid out. This function will call `free'
1521 for RLI, unless FREE_P is false. Passing a value other than false
1522 for FREE_P is bad practice; this option only exists to support the
1526 finish_record_layout (rli, free_p)
1527 record_layout_info rli;
1530 /* Compute the final size. */
1531 finalize_record_size (rli);
1533 /* Compute the TYPE_MODE for the record. */
1534 compute_record_mode (rli->t);
1536 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1537 finalize_type_size (rli->t);
1539 /* Lay out any static members. This is done now because their type
1540 may use the record's type. */
1541 while (rli->pending_statics)
1543 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1544 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1553 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1554 NAME, its fields are chained in reverse on FIELDS.
1556 If ALIGN_TYPE is non-null, it is given the same alignment as
1560 finish_builtin_struct (type, name, fields, align_type)
1568 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1570 DECL_FIELD_CONTEXT (fields) = type;
1571 next = TREE_CHAIN (fields);
1572 TREE_CHAIN (fields) = tail;
1574 TYPE_FIELDS (type) = tail;
1578 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1579 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1583 #if 0 /* not yet, should get fixed properly later */
1584 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1586 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1588 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1589 layout_decl (TYPE_NAME (type), 0);
1592 /* Calculate the mode, size, and alignment for TYPE.
1593 For an array type, calculate the element separation as well.
1594 Record TYPE on the chain of permanent or temporary types
1595 so that dbxout will find out about it.
1597 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1598 layout_type does nothing on such a type.
1600 If the type is incomplete, its TYPE_SIZE remains zero. */
1609 /* Do nothing if type has been laid out before. */
1610 if (TYPE_SIZE (type))
1613 switch (TREE_CODE (type))
1616 /* This kind of type is the responsibility
1617 of the language-specific code. */
1620 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1621 if (TYPE_PRECISION (type) == 0)
1622 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1624 /* ... fall through ... */
1629 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1630 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1631 TREE_UNSIGNED (type) = 1;
1633 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1635 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1636 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1640 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1641 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1642 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1646 TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
1648 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1649 (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
1650 ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
1652 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1653 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1660 subtype = TREE_TYPE (type);
1661 TREE_UNSIGNED (type) = TREE_UNSIGNED (subtype);
1662 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1663 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1668 /* This is an incomplete type and so doesn't have a size. */
1669 TYPE_ALIGN (type) = 1;
1670 TYPE_USER_ALIGN (type) = 0;
1671 TYPE_MODE (type) = VOIDmode;
1675 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1676 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1677 /* A pointer might be MODE_PARTIAL_INT,
1678 but ptrdiff_t must be integral. */
1679 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1684 TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
1685 TYPE_SIZE (type) = bitsize_int (2 * POINTER_SIZE);
1686 TYPE_SIZE_UNIT (type) = size_int ((2 * POINTER_SIZE) / BITS_PER_UNIT);
1690 case REFERENCE_TYPE:
1693 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1694 && reference_types_internal)
1695 ? Pmode : TYPE_MODE (type));
1697 int nbits = GET_MODE_BITSIZE (mode);
1699 TYPE_SIZE (type) = bitsize_int (nbits);
1700 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1701 TREE_UNSIGNED (type) = 1;
1702 TYPE_PRECISION (type) = nbits;
1708 tree index = TYPE_DOMAIN (type);
1709 tree element = TREE_TYPE (type);
1711 build_pointer_type (element);
1713 /* We need to know both bounds in order to compute the size. */
1714 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1715 && TYPE_SIZE (element))
1717 tree ub = TYPE_MAX_VALUE (index);
1718 tree lb = TYPE_MIN_VALUE (index);
1722 /* The initial subtraction should happen in the original type so
1723 that (possible) negative values are handled appropriately. */
1724 length = size_binop (PLUS_EXPR, size_one_node,
1726 fold (build (MINUS_EXPR,
1730 /* Special handling for arrays of bits (for Chill). */
1731 element_size = TYPE_SIZE (element);
1732 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1733 && (integer_zerop (TYPE_MAX_VALUE (element))
1734 || integer_onep (TYPE_MAX_VALUE (element)))
1735 && host_integerp (TYPE_MIN_VALUE (element), 1))
1737 HOST_WIDE_INT maxvalue
1738 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1739 HOST_WIDE_INT minvalue
1740 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1742 if (maxvalue - minvalue == 1
1743 && (maxvalue == 1 || maxvalue == 0))
1744 element_size = integer_one_node;
1747 /* If neither bound is a constant and sizetype is signed, make
1748 sure the size is never negative. We should really do this
1749 if *either* bound is non-constant, but this is the best
1750 compromise between C and Ada. */
1751 if (! TREE_UNSIGNED (sizetype)
1752 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
1753 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
1754 length = size_binop (MAX_EXPR, length, size_zero_node);
1756 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1757 convert (bitsizetype, length));
1759 /* If we know the size of the element, calculate the total
1760 size directly, rather than do some division thing below.
1761 This optimization helps Fortran assumed-size arrays
1762 (where the size of the array is determined at runtime)
1764 Note that we can't do this in the case where the size of
1765 the elements is one bit since TYPE_SIZE_UNIT cannot be
1766 set correctly in that case. */
1767 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1768 TYPE_SIZE_UNIT (type)
1769 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1772 /* Now round the alignment and size,
1773 using machine-dependent criteria if any. */
1775 #ifdef ROUND_TYPE_ALIGN
1777 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1779 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1781 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1783 #ifdef ROUND_TYPE_SIZE
1784 if (TYPE_SIZE (type) != 0)
1787 = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
1789 /* If the rounding changed the size of the type, remove any
1790 pre-calculated TYPE_SIZE_UNIT. */
1791 if (simple_cst_equal (TYPE_SIZE (type), tmp) != 1)
1792 TYPE_SIZE_UNIT (type) = NULL;
1794 TYPE_SIZE (type) = tmp;
1798 TYPE_MODE (type) = BLKmode;
1799 if (TYPE_SIZE (type) != 0
1800 #ifdef MEMBER_TYPE_FORCES_BLK
1801 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1803 /* BLKmode elements force BLKmode aggregate;
1804 else extract/store fields may lose. */
1805 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1806 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1808 /* One-element arrays get the component type's mode. */
1809 if (simple_cst_equal (TYPE_SIZE (type),
1810 TYPE_SIZE (TREE_TYPE (type))))
1811 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1814 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1816 if (TYPE_MODE (type) != BLKmode
1817 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1818 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1819 && TYPE_MODE (type) != BLKmode)
1821 TYPE_NO_FORCE_BLK (type) = 1;
1822 TYPE_MODE (type) = BLKmode;
1830 case QUAL_UNION_TYPE:
1833 record_layout_info rli;
1835 /* Initialize the layout information. */
1836 rli = start_record_layout (type);
1838 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1839 in the reverse order in building the COND_EXPR that denotes
1840 its size. We reverse them again later. */
1841 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1842 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1844 /* Place all the fields. */
1845 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1846 place_field (rli, field);
1848 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1849 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1851 if (lang_adjust_rli)
1852 (*lang_adjust_rli) (rli);
1854 /* Finish laying out the record. */
1855 finish_record_layout (rli, /*free_p=*/true);
1859 case SET_TYPE: /* Used by Chill and Pascal. */
1860 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1861 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1865 #ifndef SET_WORD_SIZE
1866 #define SET_WORD_SIZE BITS_PER_WORD
1868 unsigned int alignment
1869 = set_alignment ? set_alignment : SET_WORD_SIZE;
1870 HOST_WIDE_INT size_in_bits
1871 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), 0)
1872 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0) + 1);
1873 HOST_WIDE_INT rounded_size
1874 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1876 if (rounded_size > (int) alignment)
1877 TYPE_MODE (type) = BLKmode;
1879 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1881 TYPE_SIZE (type) = bitsize_int (rounded_size);
1882 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1883 TYPE_ALIGN (type) = alignment;
1884 TYPE_USER_ALIGN (type) = 0;
1885 TYPE_PRECISION (type) = size_in_bits;
1890 /* The size may vary in different languages, so the language front end
1891 should fill in the size. */
1892 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1893 TYPE_USER_ALIGN (type) = 0;
1894 TYPE_MODE (type) = BLKmode;
1901 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1902 records and unions, finish_record_layout already called this
1904 if (TREE_CODE (type) != RECORD_TYPE
1905 && TREE_CODE (type) != UNION_TYPE
1906 && TREE_CODE (type) != QUAL_UNION_TYPE)
1907 finalize_type_size (type);
1909 /* If this type is created before sizetype has been permanently set,
1910 record it so set_sizetype can fix it up. */
1912 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1914 /* If an alias set has been set for this aggregate when it was incomplete,
1915 force it into alias set 0.
1916 This is too conservative, but we cannot call record_component_aliases
1917 here because some frontends still change the aggregates after
1919 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1920 TYPE_ALIAS_SET (type) = 0;
1923 /* Create and return a type for signed integers of PRECISION bits. */
1926 make_signed_type (precision)
1929 tree type = make_node (INTEGER_TYPE);
1931 TYPE_PRECISION (type) = precision;
1933 fixup_signed_type (type);
1937 /* Create and return a type for unsigned integers of PRECISION bits. */
1940 make_unsigned_type (precision)
1943 tree type = make_node (INTEGER_TYPE);
1945 TYPE_PRECISION (type) = precision;
1947 fixup_unsigned_type (type);
1951 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1952 value to enable integer types to be created. */
1955 initialize_sizetypes ()
1957 tree t = make_node (INTEGER_TYPE);
1959 /* Set this so we do something reasonable for the build_int_2 calls
1961 integer_type_node = t;
1963 TYPE_MODE (t) = SImode;
1964 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1965 TYPE_USER_ALIGN (t) = 0;
1966 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1967 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1968 TREE_UNSIGNED (t) = 1;
1969 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1970 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1971 TYPE_IS_SIZETYPE (t) = 1;
1973 /* 1000 avoids problems with possible overflow and is certainly
1974 larger than any size value we'd want to be storing. */
1975 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1977 /* These two must be different nodes because of the caching done in
1980 bitsizetype = copy_node (t);
1981 integer_type_node = 0;
1984 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1985 Also update the type of any standard type's sizes made so far. */
1991 int oprecision = TYPE_PRECISION (type);
1992 /* The *bitsizetype types use a precision that avoids overflows when
1993 calculating signed sizes / offsets in bits. However, when
1994 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1996 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1997 2 * HOST_BITS_PER_WIDE_INT);
2004 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
2005 sizetype = copy_node (type);
2006 TYPE_DOMAIN (sizetype) = type;
2007 TYPE_IS_SIZETYPE (sizetype) = 1;
2008 bitsizetype = make_node (INTEGER_TYPE);
2009 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
2010 TYPE_PRECISION (bitsizetype) = precision;
2011 TYPE_IS_SIZETYPE (bitsizetype) = 1;
2013 if (TREE_UNSIGNED (type))
2014 fixup_unsigned_type (bitsizetype);
2016 fixup_signed_type (bitsizetype);
2018 layout_type (bitsizetype);
2020 if (TREE_UNSIGNED (type))
2022 usizetype = sizetype;
2023 ubitsizetype = bitsizetype;
2024 ssizetype = copy_node (make_signed_type (oprecision));
2025 sbitsizetype = copy_node (make_signed_type (precision));
2029 ssizetype = sizetype;
2030 sbitsizetype = bitsizetype;
2031 usizetype = copy_node (make_unsigned_type (oprecision));
2032 ubitsizetype = copy_node (make_unsigned_type (precision));
2035 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
2037 /* Show is a sizetype, is a main type, and has no pointers to it. */
2038 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
2040 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
2041 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
2042 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
2043 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
2044 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
2047 /* Go down each of the types we already made and set the proper type
2048 for the sizes in them. */
2049 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
2051 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE)
2054 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
2055 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
2058 early_type_list = 0;
2062 /* Set the extreme values of TYPE based on its precision in bits,
2063 then lay it out. Used when make_signed_type won't do
2064 because the tree code is not INTEGER_TYPE.
2065 E.g. for Pascal, when the -fsigned-char option is given. */
2068 fixup_signed_type (type)
2071 int precision = TYPE_PRECISION (type);
2073 /* We can not represent properly constants greater then
2074 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2075 as they are used by i386 vector extensions and friends. */
2076 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2077 precision = HOST_BITS_PER_WIDE_INT * 2;
2079 TYPE_MIN_VALUE (type)
2080 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2081 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
2082 (((HOST_WIDE_INT) (-1)
2083 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2084 ? precision - HOST_BITS_PER_WIDE_INT - 1
2086 TYPE_MAX_VALUE (type)
2087 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
2088 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2089 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2090 ? (((HOST_WIDE_INT) 1
2091 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2094 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2095 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2097 /* Lay out the type: set its alignment, size, etc. */
2101 /* Set the extreme values of TYPE based on its precision in bits,
2102 then lay it out. This is used both in `make_unsigned_type'
2103 and for enumeral types. */
2106 fixup_unsigned_type (type)
2109 int precision = TYPE_PRECISION (type);
2111 /* We can not represent properly constants greater then
2112 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2113 as they are used by i386 vector extensions and friends. */
2114 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2115 precision = HOST_BITS_PER_WIDE_INT * 2;
2117 TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
2118 TYPE_MAX_VALUE (type)
2119 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
2120 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
2121 precision - HOST_BITS_PER_WIDE_INT > 0
2122 ? ((unsigned HOST_WIDE_INT) ~0
2123 >> (HOST_BITS_PER_WIDE_INT
2124 - (precision - HOST_BITS_PER_WIDE_INT)))
2126 TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
2127 TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
2129 /* Lay out the type: set its alignment, size, etc. */
2133 /* Find the best machine mode to use when referencing a bit field of length
2134 BITSIZE bits starting at BITPOS.
2136 The underlying object is known to be aligned to a boundary of ALIGN bits.
2137 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2138 larger than LARGEST_MODE (usually SImode).
2140 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2141 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2142 mode meeting these conditions.
2144 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2145 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2146 all the conditions. */
2149 get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
2150 int bitsize, bitpos;
2152 enum machine_mode largest_mode;
2155 enum machine_mode mode;
2156 unsigned int unit = 0;
2158 /* Find the narrowest integer mode that contains the bit field. */
2159 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2160 mode = GET_MODE_WIDER_MODE (mode))
2162 unit = GET_MODE_BITSIZE (mode);
2163 if ((bitpos % unit) + bitsize <= unit)
2167 if (mode == VOIDmode
2168 /* It is tempting to omit the following line
2169 if STRICT_ALIGNMENT is true.
2170 But that is incorrect, since if the bitfield uses part of 3 bytes
2171 and we use a 4-byte mode, we could get a spurious segv
2172 if the extra 4th byte is past the end of memory.
2173 (Though at least one Unix compiler ignores this problem:
2174 that on the Sequent 386 machine. */
2175 || MIN (unit, BIGGEST_ALIGNMENT) > align
2176 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2179 if (SLOW_BYTE_ACCESS && ! volatilep)
2181 enum machine_mode wide_mode = VOIDmode, tmode;
2183 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2184 tmode = GET_MODE_WIDER_MODE (tmode))
2186 unit = GET_MODE_BITSIZE (tmode);
2187 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2188 && unit <= BITS_PER_WORD
2189 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2190 && (largest_mode == VOIDmode
2191 || unit <= GET_MODE_BITSIZE (largest_mode)))
2195 if (wide_mode != VOIDmode)
2202 #include "gt-stor-layout.h"