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"
38 /* Set to one when set_sizetype has been called. */
39 static int sizetype_set;
41 /* List of types created before set_sizetype has been called. We do not
42 make this a GGC root since we want these nodes to be reclaimed. */
43 static tree early_type_list;
45 /* Data type for the expressions representing sizes of data types.
46 It is the first integer type laid out. */
47 tree sizetype_tab[(int) TYPE_KIND_LAST];
49 /* If nonzero, this is an upper limit on alignment of structure fields.
50 The value is measured in bits. */
51 unsigned int maximum_field_alignment;
53 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
54 May be overridden by front-ends. */
55 unsigned int set_alignment = 0;
57 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
58 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
59 called only by a front end. */
60 static int reference_types_internal = 0;
62 static void finalize_record_size (record_layout_info);
63 static void finalize_type_size (tree);
64 static void place_union_field (record_layout_info, tree);
65 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
66 static int excess_unit_span (HOST_WIDE_INT, HOST_WIDE_INT, HOST_WIDE_INT,
69 static unsigned int update_alignment_for_field (record_layout_info, tree,
71 extern void debug_rli (record_layout_info);
73 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
75 static GTY(()) tree pending_sizes;
77 /* Nonzero means cannot safely call expand_expr now,
78 so put variable sizes onto `pending_sizes' instead. */
80 int immediate_size_expand;
82 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
86 internal_reference_types (void)
88 reference_types_internal = 1;
91 /* Get a list of all the objects put on the pending sizes list. */
94 get_pending_sizes (void)
96 tree chain = pending_sizes;
99 /* Put each SAVE_EXPR into the current function. */
100 for (t = chain; t; t = TREE_CHAIN (t))
101 SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
107 /* Add EXPR to the pending sizes list. */
110 put_pending_size (tree expr)
112 /* Strip any simple arithmetic from EXPR to see if it has an underlying
114 expr = skip_simple_arithmetic (expr);
116 if (TREE_CODE (expr) == SAVE_EXPR)
117 pending_sizes = tree_cons (NULL_TREE, expr, pending_sizes);
120 /* Put a chain of objects into the pending sizes list, which must be
124 put_pending_sizes (tree chain)
129 pending_sizes = chain;
132 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
133 to serve as the actual size-expression for a type or decl. */
136 variable_size (tree size)
140 /* If the language-processor is to take responsibility for variable-sized
141 items (e.g., languages which have elaboration procedures like Ada),
142 just return SIZE unchanged. Likewise for self-referential sizes and
144 if (TREE_CONSTANT (size)
145 || lang_hooks.decls.global_bindings_p () < 0
146 || CONTAINS_PLACEHOLDER_P (size))
149 if (TREE_CODE (size) == MINUS_EXPR && integer_onep (TREE_OPERAND (size, 1)))
150 /* If this is the upper bound of a C array, leave the minus 1 outside
151 the SAVE_EXPR so it can be folded away. */
152 TREE_OPERAND (size, 0) = save = save_expr (TREE_OPERAND (size, 0));
154 size = save = save_expr (size);
156 /* If an array with a variable number of elements is declared, and
157 the elements require destruction, we will emit a cleanup for the
158 array. That cleanup is run both on normal exit from the block
159 and in the exception-handler for the block. Normally, when code
160 is used in both ordinary code and in an exception handler it is
161 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
162 not wish to do that here; the array-size is the same in both
164 if (TREE_CODE (save) == SAVE_EXPR)
165 SAVE_EXPR_PERSISTENT_P (save) = 1;
167 if (lang_hooks.decls.global_bindings_p ())
169 if (TREE_CONSTANT (size))
170 error ("type size can't be explicitly evaluated");
172 error ("variable-size type declared outside of any function");
174 return size_one_node;
177 if (immediate_size_expand)
178 expand_expr (save, const0_rtx, VOIDmode, 0);
179 else if (cfun != 0 && cfun->x_dont_save_pending_sizes_p)
180 /* The front-end doesn't want us to keep a list of the expressions
181 that determine sizes for variable size objects. */
184 put_pending_size (save);
189 #ifndef MAX_FIXED_MODE_SIZE
190 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
193 /* Return the machine mode to use for a nonscalar of SIZE bits. The
194 mode must be in class CLASS, and have exactly that many value bits;
195 it may have padding as well. If LIMIT is nonzero, modes of wider
196 than MAX_FIXED_MODE_SIZE will not be used. */
199 mode_for_size (unsigned int size, enum mode_class class, int limit)
201 enum machine_mode mode;
203 if (limit && size > MAX_FIXED_MODE_SIZE)
206 /* Get the first mode which has this size, in the specified class. */
207 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
208 mode = GET_MODE_WIDER_MODE (mode))
209 if (GET_MODE_PRECISION (mode) == size)
215 /* Similar, except passed a tree node. */
218 mode_for_size_tree (tree size, enum mode_class class, int limit)
220 if (TREE_CODE (size) != INTEGER_CST
221 || TREE_OVERFLOW (size)
222 /* What we really want to say here is that the size can fit in a
223 host integer, but we know there's no way we'd find a mode for
224 this many bits, so there's no point in doing the precise test. */
225 || compare_tree_int (size, 1000) > 0)
228 return mode_for_size (tree_low_cst (size, 1), class, limit);
231 /* Similar, but never return BLKmode; return the narrowest mode that
232 contains at least the requested number of value bits. */
235 smallest_mode_for_size (unsigned int size, enum mode_class class)
237 enum machine_mode mode;
239 /* Get the first mode which has at least this size, in the
241 for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
242 mode = GET_MODE_WIDER_MODE (mode))
243 if (GET_MODE_PRECISION (mode) >= size)
249 /* Find an integer mode of the exact same size, or BLKmode on failure. */
252 int_mode_for_mode (enum machine_mode mode)
254 switch (GET_MODE_CLASS (mode))
257 case MODE_PARTIAL_INT:
260 case MODE_COMPLEX_INT:
261 case MODE_COMPLEX_FLOAT:
263 case MODE_VECTOR_INT:
264 case MODE_VECTOR_FLOAT:
265 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
272 /* ... fall through ... */
282 /* Return the alignment of MODE. This will be bounded by 1 and
283 BIGGEST_ALIGNMENT. */
286 get_mode_alignment (enum machine_mode mode)
288 return MIN (BIGGEST_ALIGNMENT, MAX (1, mode_base_align[mode]*BITS_PER_UNIT));
291 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
292 This can only be applied to objects of a sizetype. */
295 round_up (tree value, int divisor)
297 tree arg = size_int_type (divisor, TREE_TYPE (value));
299 return size_binop (MULT_EXPR, size_binop (CEIL_DIV_EXPR, value, arg), arg);
302 /* Likewise, but round down. */
305 round_down (tree value, int divisor)
307 tree arg = size_int_type (divisor, TREE_TYPE (value));
309 return size_binop (MULT_EXPR, size_binop (FLOOR_DIV_EXPR, value, arg), arg);
312 /* Subroutine of layout_decl: Force alignment required for the data type.
313 But if the decl itself wants greater alignment, don't override that. */
316 do_type_align (tree type, tree decl)
318 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
320 DECL_ALIGN (decl) = TYPE_ALIGN (type);
321 if (TREE_CODE (decl) == FIELD_DECL)
322 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
326 /* Set the size, mode and alignment of a ..._DECL node.
327 TYPE_DECL does need this for C++.
328 Note that LABEL_DECL and CONST_DECL nodes do not need this,
329 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
330 Don't call layout_decl for them.
332 KNOWN_ALIGN is the amount of alignment we can assume this
333 decl has with no special effort. It is relevant only for FIELD_DECLs
334 and depends on the previous fields.
335 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
336 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
337 the record will be aligned to suit. */
340 layout_decl (tree decl, unsigned int known_align)
342 tree type = TREE_TYPE (decl);
343 enum tree_code code = TREE_CODE (decl);
346 if (code == CONST_DECL)
348 else if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
349 && code != TYPE_DECL && code != FIELD_DECL)
352 rtl = DECL_RTL_IF_SET (decl);
354 if (type == error_mark_node)
355 type = void_type_node;
357 /* Usually the size and mode come from the data type without change,
358 however, the front-end may set the explicit width of the field, so its
359 size may not be the same as the size of its type. This happens with
360 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
361 also happens with other fields. For example, the C++ front-end creates
362 zero-sized fields corresponding to empty base classes, and depends on
363 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
364 size in bytes from the size in bits. If we have already set the mode,
365 don't set it again since we can be called twice for FIELD_DECLs. */
367 DECL_UNSIGNED (decl) = TYPE_UNSIGNED (type);
368 if (DECL_MODE (decl) == VOIDmode)
369 DECL_MODE (decl) = TYPE_MODE (type);
371 if (DECL_SIZE (decl) == 0)
373 DECL_SIZE (decl) = TYPE_SIZE (type);
374 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
376 else if (DECL_SIZE_UNIT (decl) == 0)
377 DECL_SIZE_UNIT (decl)
378 = convert (sizetype, size_binop (CEIL_DIV_EXPR, DECL_SIZE (decl),
381 if (code != FIELD_DECL)
382 /* For non-fields, update the alignment from the type. */
383 do_type_align (type, decl);
385 /* For fields, it's a bit more complicated... */
387 bool old_user_align = DECL_USER_ALIGN (decl);
389 if (DECL_BIT_FIELD (decl))
391 DECL_BIT_FIELD_TYPE (decl) = type;
393 /* A zero-length bit-field affects the alignment of the next
395 if (integer_zerop (DECL_SIZE (decl))
396 && ! DECL_PACKED (decl)
397 && ! targetm.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl)))
399 #ifdef PCC_BITFIELD_TYPE_MATTERS
400 if (PCC_BITFIELD_TYPE_MATTERS)
401 do_type_align (type, decl);
405 #ifdef EMPTY_FIELD_BOUNDARY
406 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
408 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
409 DECL_USER_ALIGN (decl) = 0;
415 /* See if we can use an ordinary integer mode for a bit-field.
416 Conditions are: a fixed size that is correct for another mode
417 and occupying a complete byte or bytes on proper boundary. */
418 if (TYPE_SIZE (type) != 0
419 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
420 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT)
422 enum machine_mode xmode
423 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
427 || known_align >= GET_MODE_ALIGNMENT (xmode)))
429 DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
431 DECL_MODE (decl) = xmode;
432 DECL_BIT_FIELD (decl) = 0;
436 /* Turn off DECL_BIT_FIELD if we won't need it set. */
437 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
438 && known_align >= TYPE_ALIGN (type)
439 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
440 DECL_BIT_FIELD (decl) = 0;
442 else if (DECL_PACKED (decl) && DECL_USER_ALIGN (decl))
443 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
444 round up; we'll reduce it again below. We want packing to
445 supersede USER_ALIGN inherited from the type, but defer to
446 alignment explicitly specified on the field decl. */;
448 do_type_align (type, decl);
450 /* If the field is of variable size, we can't misalign it since we
451 have no way to make a temporary to align the result. But this
452 isn't an issue if the decl is not addressable. Likewise if it
455 Note that do_type_align may set DECL_USER_ALIGN, so we need to
456 check old_user_align instead. */
457 if (DECL_PACKED (decl)
459 && (DECL_NONADDRESSABLE_P (decl)
460 || DECL_SIZE_UNIT (decl) == 0
461 || TREE_CODE (DECL_SIZE_UNIT (decl)) == INTEGER_CST))
462 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
464 /* Should this be controlled by DECL_USER_ALIGN, too? */
465 if (maximum_field_alignment != 0)
466 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
467 if (! DECL_USER_ALIGN (decl))
469 /* Some targets (i.e. i386, VMS) limit struct field alignment
470 to a lower boundary than alignment of variables unless
471 it was overridden by attribute aligned. */
472 #ifdef BIGGEST_FIELD_ALIGNMENT
474 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
476 #ifdef ADJUST_FIELD_ALIGN
477 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
482 /* Evaluate nonconstant size only once, either now or as soon as safe. */
483 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
484 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
485 if (DECL_SIZE_UNIT (decl) != 0
486 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
487 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
489 /* If requested, warn about definitions of large data objects. */
491 && (code == VAR_DECL || code == PARM_DECL)
492 && ! DECL_EXTERNAL (decl))
494 tree size = DECL_SIZE_UNIT (decl);
496 if (size != 0 && TREE_CODE (size) == INTEGER_CST
497 && compare_tree_int (size, larger_than_size) > 0)
499 int size_as_int = TREE_INT_CST_LOW (size);
501 if (compare_tree_int (size, size_as_int) == 0)
502 warning ("%Jsize of '%D' is %d bytes", decl, decl, size_as_int);
504 warning ("%Jsize of '%D' is larger than %d bytes",
505 decl, decl, larger_than_size);
509 /* If the RTL was already set, update its mode and mem attributes. */
512 PUT_MODE (rtl, DECL_MODE (decl));
513 SET_DECL_RTL (decl, 0);
514 set_mem_attributes (rtl, decl, 1);
515 SET_DECL_RTL (decl, rtl);
519 /* Hook for a front-end function that can modify the record layout as needed
520 immediately before it is finalized. */
522 void (*lang_adjust_rli) (record_layout_info) = 0;
525 set_lang_adjust_rli (void (*f) (record_layout_info))
530 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
531 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
532 is to be passed to all other layout functions for this record. It is the
533 responsibility of the caller to call `free' for the storage returned.
534 Note that garbage collection is not permitted until we finish laying
538 start_record_layout (tree t)
540 record_layout_info rli = xmalloc (sizeof (struct record_layout_info_s));
544 /* If the type has a minimum specified alignment (via an attribute
545 declaration, for example) use it -- otherwise, start with a
546 one-byte alignment. */
547 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
548 rli->unpacked_align = rli->record_align;
549 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
551 #ifdef STRUCTURE_SIZE_BOUNDARY
552 /* Packed structures don't need to have minimum size. */
553 if (! TYPE_PACKED (t))
554 rli->record_align = MAX (rli->record_align, (unsigned) STRUCTURE_SIZE_BOUNDARY);
557 rli->offset = size_zero_node;
558 rli->bitpos = bitsize_zero_node;
560 rli->pending_statics = 0;
561 rli->packed_maybe_necessary = 0;
566 /* These four routines perform computations that convert between
567 the offset/bitpos forms and byte and bit offsets. */
570 bit_from_pos (tree offset, tree bitpos)
572 return size_binop (PLUS_EXPR, bitpos,
573 size_binop (MULT_EXPR, convert (bitsizetype, offset),
578 byte_from_pos (tree offset, tree bitpos)
580 return size_binop (PLUS_EXPR, offset,
582 size_binop (TRUNC_DIV_EXPR, bitpos,
583 bitsize_unit_node)));
587 pos_from_bit (tree *poffset, tree *pbitpos, unsigned int off_align,
590 *poffset = size_binop (MULT_EXPR,
592 size_binop (FLOOR_DIV_EXPR, pos,
593 bitsize_int (off_align))),
594 size_int (off_align / BITS_PER_UNIT));
595 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
598 /* Given a pointer to bit and byte offsets and an offset alignment,
599 normalize the offsets so they are within the alignment. */
602 normalize_offset (tree *poffset, tree *pbitpos, unsigned int off_align)
604 /* If the bit position is now larger than it should be, adjust it
606 if (compare_tree_int (*pbitpos, off_align) >= 0)
608 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
609 bitsize_int (off_align));
612 = size_binop (PLUS_EXPR, *poffset,
613 size_binop (MULT_EXPR, convert (sizetype, extra_aligns),
614 size_int (off_align / BITS_PER_UNIT)));
617 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
621 /* Print debugging information about the information in RLI. */
624 debug_rli (record_layout_info rli)
626 print_node_brief (stderr, "type", rli->t, 0);
627 print_node_brief (stderr, "\noffset", rli->offset, 0);
628 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
630 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
631 rli->record_align, rli->unpacked_align,
633 if (rli->packed_maybe_necessary)
634 fprintf (stderr, "packed may be necessary\n");
636 if (rli->pending_statics)
638 fprintf (stderr, "pending statics:\n");
639 debug_tree (rli->pending_statics);
643 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
644 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
647 normalize_rli (record_layout_info rli)
649 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
652 /* Returns the size in bytes allocated so far. */
655 rli_size_unit_so_far (record_layout_info rli)
657 return byte_from_pos (rli->offset, rli->bitpos);
660 /* Returns the size in bits allocated so far. */
663 rli_size_so_far (record_layout_info rli)
665 return bit_from_pos (rli->offset, rli->bitpos);
668 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
669 the next available location is given by KNOWN_ALIGN. Update the
670 variable alignment fields in RLI, and return the alignment to give
674 update_alignment_for_field (record_layout_info rli, tree field,
675 unsigned int known_align)
677 /* The alignment required for FIELD. */
678 unsigned int desired_align;
679 /* The type of this field. */
680 tree type = TREE_TYPE (field);
681 /* True if the field was explicitly aligned by the user. */
685 /* Lay out the field so we know what alignment it needs. */
686 layout_decl (field, known_align);
687 desired_align = DECL_ALIGN (field);
688 user_align = DECL_USER_ALIGN (field);
690 is_bitfield = (type != error_mark_node
691 && DECL_BIT_FIELD_TYPE (field)
692 && ! integer_zerop (TYPE_SIZE (type)));
694 /* Record must have at least as much alignment as any field.
695 Otherwise, the alignment of the field within the record is
697 if (is_bitfield && targetm.ms_bitfield_layout_p (rli->t))
699 /* Here, the alignment of the underlying type of a bitfield can
700 affect the alignment of a record; even a zero-sized field
701 can do this. The alignment should be to the alignment of
702 the type, except that for zero-size bitfields this only
703 applies if there was an immediately prior, nonzero-size
704 bitfield. (That's the way it is, experimentally.) */
705 if (! integer_zerop (DECL_SIZE (field))
706 ? ! DECL_PACKED (field)
708 && DECL_BIT_FIELD_TYPE (rli->prev_field)
709 && ! integer_zerop (DECL_SIZE (rli->prev_field))))
711 unsigned int type_align = TYPE_ALIGN (type);
712 type_align = MAX (type_align, desired_align);
713 if (maximum_field_alignment != 0)
714 type_align = MIN (type_align, maximum_field_alignment);
715 rli->record_align = MAX (rli->record_align, type_align);
716 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
719 #ifdef PCC_BITFIELD_TYPE_MATTERS
720 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
722 /* Named bit-fields cause the entire structure to have the
723 alignment implied by their type. */
724 if (DECL_NAME (field) != 0)
726 unsigned int type_align = TYPE_ALIGN (type);
728 #ifdef ADJUST_FIELD_ALIGN
729 if (! TYPE_USER_ALIGN (type))
730 type_align = ADJUST_FIELD_ALIGN (field, type_align);
733 if (maximum_field_alignment != 0)
734 type_align = MIN (type_align, maximum_field_alignment);
735 else if (DECL_PACKED (field))
736 type_align = MIN (type_align, BITS_PER_UNIT);
738 /* The alignment of the record is increased to the maximum
739 of the current alignment, the alignment indicated on the
740 field (i.e., the alignment specified by an __aligned__
741 attribute), and the alignment indicated by the type of
743 rli->record_align = MAX (rli->record_align, desired_align);
744 rli->record_align = MAX (rli->record_align, type_align);
747 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
748 user_align |= TYPE_USER_ALIGN (type);
754 rli->record_align = MAX (rli->record_align, desired_align);
755 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
758 TYPE_USER_ALIGN (rli->t) |= user_align;
760 return desired_align;
763 /* Called from place_field to handle unions. */
766 place_union_field (record_layout_info rli, tree field)
768 update_alignment_for_field (rli, field, /*known_align=*/0);
770 DECL_FIELD_OFFSET (field) = size_zero_node;
771 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
772 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
774 /* We assume the union's size will be a multiple of a byte so we don't
775 bother with BITPOS. */
776 if (TREE_CODE (rli->t) == UNION_TYPE)
777 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
778 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
779 rli->offset = fold (build (COND_EXPR, sizetype,
780 DECL_QUALIFIER (field),
781 DECL_SIZE_UNIT (field), rli->offset));
784 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
785 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
786 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
787 units of alignment than the underlying TYPE. */
789 excess_unit_span (HOST_WIDE_INT byte_offset, HOST_WIDE_INT bit_offset,
790 HOST_WIDE_INT size, HOST_WIDE_INT align, tree type)
792 /* Note that the calculation of OFFSET might overflow; we calculate it so
793 that we still get the right result as long as ALIGN is a power of two. */
794 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
796 offset = offset % align;
797 return ((offset + size + align - 1) / align
798 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
803 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
804 is a FIELD_DECL to be added after those fields already present in
805 T. (FIELD is not actually added to the TYPE_FIELDS list here;
806 callers that desire that behavior must manually perform that step.) */
809 place_field (record_layout_info rli, tree field)
811 /* The alignment required for FIELD. */
812 unsigned int desired_align;
813 /* The alignment FIELD would have if we just dropped it into the
814 record as it presently stands. */
815 unsigned int known_align;
816 unsigned int actual_align;
817 /* The type of this field. */
818 tree type = TREE_TYPE (field);
820 if (TREE_CODE (field) == ERROR_MARK || TREE_CODE (type) == ERROR_MARK)
823 /* If FIELD is static, then treat it like a separate variable, not
824 really like a structure field. If it is a FUNCTION_DECL, it's a
825 method. In both cases, all we do is lay out the decl, and we do
826 it *after* the record is laid out. */
827 if (TREE_CODE (field) == VAR_DECL)
829 rli->pending_statics = tree_cons (NULL_TREE, field,
830 rli->pending_statics);
834 /* Enumerators and enum types which are local to this class need not
835 be laid out. Likewise for initialized constant fields. */
836 else if (TREE_CODE (field) != FIELD_DECL)
839 /* Unions are laid out very differently than records, so split
840 that code off to another function. */
841 else if (TREE_CODE (rli->t) != RECORD_TYPE)
843 place_union_field (rli, field);
847 /* Work out the known alignment so far. Note that A & (-A) is the
848 value of the least-significant bit in A that is one. */
849 if (! integer_zerop (rli->bitpos))
850 known_align = (tree_low_cst (rli->bitpos, 1)
851 & - tree_low_cst (rli->bitpos, 1));
852 else if (integer_zerop (rli->offset))
853 known_align = BIGGEST_ALIGNMENT;
854 else if (host_integerp (rli->offset, 1))
855 known_align = (BITS_PER_UNIT
856 * (tree_low_cst (rli->offset, 1)
857 & - tree_low_cst (rli->offset, 1)));
859 known_align = rli->offset_align;
861 desired_align = update_alignment_for_field (rli, field, known_align);
863 if (warn_packed && DECL_PACKED (field))
865 if (known_align >= TYPE_ALIGN (type))
867 if (TYPE_ALIGN (type) > desired_align)
869 if (STRICT_ALIGNMENT)
870 warning ("%Jpacked attribute causes inefficient alignment "
871 "for '%D'", field, field);
873 warning ("%Jpacked attribute is unnecessary for '%D'",
878 rli->packed_maybe_necessary = 1;
881 /* Does this field automatically have alignment it needs by virtue
882 of the fields that precede it and the record's own alignment? */
883 if (known_align < desired_align)
885 /* No, we need to skip space before this field.
886 Bump the cumulative size to multiple of field alignment. */
889 warning ("%Jpadding struct to align '%D'", field, field);
891 /* If the alignment is still within offset_align, just align
893 if (desired_align < rli->offset_align)
894 rli->bitpos = round_up (rli->bitpos, desired_align);
897 /* First adjust OFFSET by the partial bits, then align. */
899 = size_binop (PLUS_EXPR, rli->offset,
901 size_binop (CEIL_DIV_EXPR, rli->bitpos,
902 bitsize_unit_node)));
903 rli->bitpos = bitsize_zero_node;
905 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
908 if (! TREE_CONSTANT (rli->offset))
909 rli->offset_align = desired_align;
913 /* Handle compatibility with PCC. Note that if the record has any
914 variable-sized fields, we need not worry about compatibility. */
915 #ifdef PCC_BITFIELD_TYPE_MATTERS
916 if (PCC_BITFIELD_TYPE_MATTERS
917 && ! targetm.ms_bitfield_layout_p (rli->t)
918 && TREE_CODE (field) == FIELD_DECL
919 && type != error_mark_node
920 && DECL_BIT_FIELD (field)
921 && ! DECL_PACKED (field)
922 && maximum_field_alignment == 0
923 && ! integer_zerop (DECL_SIZE (field))
924 && host_integerp (DECL_SIZE (field), 1)
925 && host_integerp (rli->offset, 1)
926 && host_integerp (TYPE_SIZE (type), 1))
928 unsigned int type_align = TYPE_ALIGN (type);
929 tree dsize = DECL_SIZE (field);
930 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
931 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
932 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
934 #ifdef ADJUST_FIELD_ALIGN
935 if (! TYPE_USER_ALIGN (type))
936 type_align = ADJUST_FIELD_ALIGN (field, type_align);
939 /* A bit field may not span more units of alignment of its type
940 than its type itself. Advance to next boundary if necessary. */
941 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
942 rli->bitpos = round_up (rli->bitpos, type_align);
944 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
948 #ifdef BITFIELD_NBYTES_LIMITED
949 if (BITFIELD_NBYTES_LIMITED
950 && ! targetm.ms_bitfield_layout_p (rli->t)
951 && TREE_CODE (field) == FIELD_DECL
952 && type != error_mark_node
953 && DECL_BIT_FIELD_TYPE (field)
954 && ! DECL_PACKED (field)
955 && ! integer_zerop (DECL_SIZE (field))
956 && host_integerp (DECL_SIZE (field), 1)
957 && host_integerp (rli->offset, 1)
958 && host_integerp (TYPE_SIZE (type), 1))
960 unsigned int type_align = TYPE_ALIGN (type);
961 tree dsize = DECL_SIZE (field);
962 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
963 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
964 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
966 #ifdef ADJUST_FIELD_ALIGN
967 if (! TYPE_USER_ALIGN (type))
968 type_align = ADJUST_FIELD_ALIGN (field, type_align);
971 if (maximum_field_alignment != 0)
972 type_align = MIN (type_align, maximum_field_alignment);
973 /* ??? This test is opposite the test in the containing if
974 statement, so this code is unreachable currently. */
975 else if (DECL_PACKED (field))
976 type_align = MIN (type_align, BITS_PER_UNIT);
978 /* A bit field may not span the unit of alignment of its type.
979 Advance to next boundary if necessary. */
980 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
981 rli->bitpos = round_up (rli->bitpos, type_align);
983 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
987 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
989 When a bit field is inserted into a packed record, the whole
990 size of the underlying type is used by one or more same-size
991 adjacent bitfields. (That is, if its long:3, 32 bits is
992 used in the record, and any additional adjacent long bitfields are
993 packed into the same chunk of 32 bits. However, if the size
994 changes, a new field of that size is allocated.) In an unpacked
995 record, this is the same as using alignment, but not equivalent
998 Note: for compatibility, we use the type size, not the type alignment
999 to determine alignment, since that matches the documentation */
1001 if (targetm.ms_bitfield_layout_p (rli->t)
1002 && ((DECL_BIT_FIELD_TYPE (field) && ! DECL_PACKED (field))
1003 || (rli->prev_field && ! DECL_PACKED (rli->prev_field))))
1005 /* At this point, either the prior or current are bitfields,
1006 (possibly both), and we're dealing with MS packing. */
1007 tree prev_saved = rli->prev_field;
1009 /* Is the prior field a bitfield? If so, handle "runs" of same
1010 type size fields. */
1011 if (rli->prev_field /* necessarily a bitfield if it exists. */)
1013 /* If both are bitfields, nonzero, and the same size, this is
1014 the middle of a run. Zero declared size fields are special
1015 and handled as "end of run". (Note: it's nonzero declared
1016 size, but equal type sizes!) (Since we know that both
1017 the current and previous fields are bitfields by the
1018 time we check it, DECL_SIZE must be present for both.) */
1019 if (DECL_BIT_FIELD_TYPE (field)
1020 && !integer_zerop (DECL_SIZE (field))
1021 && !integer_zerop (DECL_SIZE (rli->prev_field))
1022 && host_integerp (DECL_SIZE (rli->prev_field), 0)
1023 && host_integerp (TYPE_SIZE (type), 0)
1024 && simple_cst_equal (TYPE_SIZE (type),
1025 TYPE_SIZE (TREE_TYPE (rli->prev_field))))
1027 /* We're in the middle of a run of equal type size fields; make
1028 sure we realign if we run out of bits. (Not decl size,
1030 HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 0);
1032 if (rli->remaining_in_alignment < bitsize)
1034 /* out of bits; bump up to next 'word'. */
1035 rli->offset = DECL_FIELD_OFFSET (rli->prev_field);
1037 = size_binop (PLUS_EXPR, TYPE_SIZE (type),
1038 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1039 rli->prev_field = field;
1040 rli->remaining_in_alignment
1041 = tree_low_cst (TYPE_SIZE (type), 0);
1044 rli->remaining_in_alignment -= bitsize;
1048 /* End of a run: if leaving a run of bitfields of the same type
1049 size, we have to "use up" the rest of the bits of the type
1052 Compute the new position as the sum of the size for the prior
1053 type and where we first started working on that type.
1054 Note: since the beginning of the field was aligned then
1055 of course the end will be too. No round needed. */
1057 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1059 tree type_size = TYPE_SIZE (TREE_TYPE (rli->prev_field));
1062 = size_binop (PLUS_EXPR, type_size,
1063 DECL_FIELD_BIT_OFFSET (rli->prev_field));
1066 /* We "use up" size zero fields; the code below should behave
1067 as if the prior field was not a bitfield. */
1070 /* Cause a new bitfield to be captured, either this time (if
1071 currently a bitfield) or next time we see one. */
1072 if (!DECL_BIT_FIELD_TYPE(field)
1073 || integer_zerop (DECL_SIZE (field)))
1074 rli->prev_field = NULL;
1077 rli->offset_align = tree_low_cst (TYPE_SIZE (type), 0);
1078 normalize_rli (rli);
1081 /* If we're starting a new run of same size type bitfields
1082 (or a run of non-bitfields), set up the "first of the run"
1085 That is, if the current field is not a bitfield, or if there
1086 was a prior bitfield the type sizes differ, or if there wasn't
1087 a prior bitfield the size of the current field is nonzero.
1089 Note: we must be sure to test ONLY the type size if there was
1090 a prior bitfield and ONLY for the current field being zero if
1093 if (!DECL_BIT_FIELD_TYPE (field)
1094 || ( prev_saved != NULL
1095 ? !simple_cst_equal (TYPE_SIZE (type),
1096 TYPE_SIZE (TREE_TYPE (prev_saved)))
1097 : !integer_zerop (DECL_SIZE (field)) ))
1099 /* Never smaller than a byte for compatibility. */
1100 unsigned int type_align = BITS_PER_UNIT;
1102 /* (When not a bitfield), we could be seeing a flex array (with
1103 no DECL_SIZE). Since we won't be using remaining_in_alignment
1104 until we see a bitfield (and come by here again) we just skip
1106 if (DECL_SIZE (field) != NULL
1107 && host_integerp (TYPE_SIZE (TREE_TYPE (field)), 0)
1108 && host_integerp (DECL_SIZE (field), 0))
1109 rli->remaining_in_alignment
1110 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field)), 0)
1111 - tree_low_cst (DECL_SIZE (field), 0);
1113 /* Now align (conventionally) for the new type. */
1114 if (!DECL_PACKED(field))
1115 type_align = MAX(TYPE_ALIGN (type), type_align);
1118 && DECL_BIT_FIELD_TYPE (prev_saved)
1119 /* If the previous bit-field is zero-sized, we've already
1120 accounted for its alignment needs (or ignored it, if
1121 appropriate) while placing it. */
1122 && ! integer_zerop (DECL_SIZE (prev_saved)))
1123 type_align = MAX (type_align,
1124 TYPE_ALIGN (TREE_TYPE (prev_saved)));
1126 if (maximum_field_alignment != 0)
1127 type_align = MIN (type_align, maximum_field_alignment);
1129 rli->bitpos = round_up (rli->bitpos, type_align);
1131 /* If we really aligned, don't allow subsequent bitfields
1133 rli->prev_field = NULL;
1137 /* Offset so far becomes the position of this field after normalizing. */
1138 normalize_rli (rli);
1139 DECL_FIELD_OFFSET (field) = rli->offset;
1140 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1141 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1143 /* If this field ended up more aligned than we thought it would be (we
1144 approximate this by seeing if its position changed), lay out the field
1145 again; perhaps we can use an integral mode for it now. */
1146 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1147 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1148 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1149 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1150 actual_align = BIGGEST_ALIGNMENT;
1151 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1152 actual_align = (BITS_PER_UNIT
1153 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1154 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1156 actual_align = DECL_OFFSET_ALIGN (field);
1158 if (known_align != actual_align)
1159 layout_decl (field, actual_align);
1161 /* Only the MS bitfields use this. */
1162 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE(field))
1163 rli->prev_field = field;
1165 /* Now add size of this field to the size of the record. If the size is
1166 not constant, treat the field as being a multiple of bytes and just
1167 adjust the offset, resetting the bit position. Otherwise, apportion the
1168 size amongst the bit position and offset. First handle the case of an
1169 unspecified size, which can happen when we have an invalid nested struct
1170 definition, such as struct j { struct j { int i; } }. The error message
1171 is printed in finish_struct. */
1172 if (DECL_SIZE (field) == 0)
1174 else if (TREE_CODE (DECL_SIZE_UNIT (field)) != INTEGER_CST
1175 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field)))
1178 = size_binop (PLUS_EXPR, rli->offset,
1180 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1181 bitsize_unit_node)));
1183 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1184 rli->bitpos = bitsize_zero_node;
1185 rli->offset_align = MIN (rli->offset_align, desired_align);
1189 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1190 normalize_rli (rli);
1194 /* Assuming that all the fields have been laid out, this function uses
1195 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1196 indicated by RLI. */
1199 finalize_record_size (record_layout_info rli)
1201 tree unpadded_size, unpadded_size_unit;
1203 /* Now we want just byte and bit offsets, so set the offset alignment
1204 to be a byte and then normalize. */
1205 rli->offset_align = BITS_PER_UNIT;
1206 normalize_rli (rli);
1208 /* Determine the desired alignment. */
1209 #ifdef ROUND_TYPE_ALIGN
1210 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1213 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1216 /* Compute the size so far. Be sure to allow for extra bits in the
1217 size in bytes. We have guaranteed above that it will be no more
1218 than a single byte. */
1219 unpadded_size = rli_size_so_far (rli);
1220 unpadded_size_unit = rli_size_unit_so_far (rli);
1221 if (! integer_zerop (rli->bitpos))
1223 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1225 /* Round the size up to be a multiple of the required alignment. */
1226 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1227 TYPE_SIZE_UNIT (rli->t) = round_up (unpadded_size_unit,
1228 TYPE_ALIGN (rli->t) / BITS_PER_UNIT);
1230 if (warn_padded && TREE_CONSTANT (unpadded_size)
1231 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0)
1232 warning ("padding struct size to alignment boundary");
1234 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1235 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1236 && TREE_CONSTANT (unpadded_size))
1240 #ifdef ROUND_TYPE_ALIGN
1242 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1244 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1247 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1248 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1250 TYPE_PACKED (rli->t) = 0;
1252 if (TYPE_NAME (rli->t))
1256 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1257 name = IDENTIFIER_POINTER (TYPE_NAME (rli->t));
1259 name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli->t)));
1261 if (STRICT_ALIGNMENT)
1262 warning ("packed attribute causes inefficient alignment for `%s'", name);
1264 warning ("packed attribute is unnecessary for `%s'", name);
1268 if (STRICT_ALIGNMENT)
1269 warning ("packed attribute causes inefficient alignment");
1271 warning ("packed attribute is unnecessary");
1277 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1280 compute_record_mode (tree type)
1283 enum machine_mode mode = VOIDmode;
1285 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1286 However, if possible, we use a mode that fits in a register
1287 instead, in order to allow for better optimization down the
1289 TYPE_MODE (type) = BLKmode;
1291 if (! host_integerp (TYPE_SIZE (type), 1))
1294 /* A record which has any BLKmode members must itself be
1295 BLKmode; it can't go in a register. Unless the member is
1296 BLKmode only because it isn't aligned. */
1297 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1299 if (TREE_CODE (field) != FIELD_DECL)
1302 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1303 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1304 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))
1305 && !(TYPE_SIZE (TREE_TYPE (field)) != 0
1306 && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))))
1307 || ! host_integerp (bit_position (field), 1)
1308 || DECL_SIZE (field) == 0
1309 || ! host_integerp (DECL_SIZE (field), 1))
1312 /* If this field is the whole struct, remember its mode so
1313 that, say, we can put a double in a class into a DF
1314 register instead of forcing it to live in the stack. */
1315 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1316 mode = DECL_MODE (field);
1318 #ifdef MEMBER_TYPE_FORCES_BLK
1319 /* With some targets, eg. c4x, it is sub-optimal
1320 to access an aligned BLKmode structure as a scalar. */
1322 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1324 #endif /* MEMBER_TYPE_FORCES_BLK */
1327 /* If we only have one real field; use its mode. This only applies to
1328 RECORD_TYPE. This does not apply to unions. */
1329 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode)
1330 TYPE_MODE (type) = mode;
1332 TYPE_MODE (type) = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1334 /* If structure's known alignment is less than what the scalar
1335 mode would need, and it matters, then stick with BLKmode. */
1336 if (TYPE_MODE (type) != BLKmode
1338 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1339 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1341 /* If this is the only reason this type is BLKmode, then
1342 don't force containing types to be BLKmode. */
1343 TYPE_NO_FORCE_BLK (type) = 1;
1344 TYPE_MODE (type) = BLKmode;
1348 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1352 finalize_type_size (tree type)
1354 /* Normally, use the alignment corresponding to the mode chosen.
1355 However, where strict alignment is not required, avoid
1356 over-aligning structures, since most compilers do not do this
1359 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1360 && (STRICT_ALIGNMENT
1361 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1362 && TREE_CODE (type) != QUAL_UNION_TYPE
1363 && TREE_CODE (type) != ARRAY_TYPE)))
1365 TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1366 TYPE_USER_ALIGN (type) = 0;
1369 /* Do machine-dependent extra alignment. */
1370 #ifdef ROUND_TYPE_ALIGN
1372 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1375 /* If we failed to find a simple way to calculate the unit size
1376 of the type, find it by division. */
1377 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1378 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1379 result will fit in sizetype. We will get more efficient code using
1380 sizetype, so we force a conversion. */
1381 TYPE_SIZE_UNIT (type)
1382 = convert (sizetype,
1383 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1384 bitsize_unit_node));
1386 if (TYPE_SIZE (type) != 0)
1388 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1389 TYPE_SIZE_UNIT (type)
1390 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN (type) / BITS_PER_UNIT);
1393 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1394 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1395 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1396 if (TYPE_SIZE_UNIT (type) != 0
1397 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1398 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1400 /* Also layout any other variants of the type. */
1401 if (TYPE_NEXT_VARIANT (type)
1402 || type != TYPE_MAIN_VARIANT (type))
1405 /* Record layout info of this variant. */
1406 tree size = TYPE_SIZE (type);
1407 tree size_unit = TYPE_SIZE_UNIT (type);
1408 unsigned int align = TYPE_ALIGN (type);
1409 unsigned int user_align = TYPE_USER_ALIGN (type);
1410 enum machine_mode mode = TYPE_MODE (type);
1412 /* Copy it into all variants. */
1413 for (variant = TYPE_MAIN_VARIANT (type);
1415 variant = TYPE_NEXT_VARIANT (variant))
1417 TYPE_SIZE (variant) = size;
1418 TYPE_SIZE_UNIT (variant) = size_unit;
1419 TYPE_ALIGN (variant) = align;
1420 TYPE_USER_ALIGN (variant) = user_align;
1421 TYPE_MODE (variant) = mode;
1426 /* Do all of the work required to layout the type indicated by RLI,
1427 once the fields have been laid out. This function will call `free'
1428 for RLI, unless FREE_P is false. Passing a value other than false
1429 for FREE_P is bad practice; this option only exists to support the
1433 finish_record_layout (record_layout_info rli, int free_p)
1435 /* Compute the final size. */
1436 finalize_record_size (rli);
1438 /* Compute the TYPE_MODE for the record. */
1439 compute_record_mode (rli->t);
1441 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1442 finalize_type_size (rli->t);
1444 /* Lay out any static members. This is done now because their type
1445 may use the record's type. */
1446 while (rli->pending_statics)
1448 layout_decl (TREE_VALUE (rli->pending_statics), 0);
1449 rli->pending_statics = TREE_CHAIN (rli->pending_statics);
1458 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1459 NAME, its fields are chained in reverse on FIELDS.
1461 If ALIGN_TYPE is non-null, it is given the same alignment as
1465 finish_builtin_struct (tree type, const char *name, tree fields,
1470 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1472 DECL_FIELD_CONTEXT (fields) = type;
1473 next = TREE_CHAIN (fields);
1474 TREE_CHAIN (fields) = tail;
1476 TYPE_FIELDS (type) = tail;
1480 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1481 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1485 #if 0 /* not yet, should get fixed properly later */
1486 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1488 TYPE_NAME (type) = build_decl (TYPE_DECL, get_identifier (name), type);
1490 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1491 layout_decl (TYPE_NAME (type), 0);
1494 /* Calculate the mode, size, and alignment for TYPE.
1495 For an array type, calculate the element separation as well.
1496 Record TYPE on the chain of permanent or temporary types
1497 so that dbxout will find out about it.
1499 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1500 layout_type does nothing on such a type.
1502 If the type is incomplete, its TYPE_SIZE remains zero. */
1505 layout_type (tree type)
1510 /* Do nothing if type has been laid out before. */
1511 if (TYPE_SIZE (type))
1514 switch (TREE_CODE (type))
1517 /* This kind of type is the responsibility
1518 of the language-specific code. */
1521 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1522 if (TYPE_PRECISION (type) == 0)
1523 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1525 /* ... fall through ... */
1530 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1531 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1532 TYPE_UNSIGNED (type) = 1;
1534 TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
1536 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1537 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1541 TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
1542 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1543 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1547 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1549 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1550 (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE
1551 ? MODE_COMPLEX_FLOAT : MODE_COMPLEX_INT),
1553 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1554 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1558 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1559 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1560 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1564 /* This is an incomplete type and so doesn't have a size. */
1565 TYPE_ALIGN (type) = 1;
1566 TYPE_USER_ALIGN (type) = 0;
1567 TYPE_MODE (type) = VOIDmode;
1571 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1572 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1573 /* A pointer might be MODE_PARTIAL_INT,
1574 but ptrdiff_t must be integral. */
1575 TYPE_MODE (type) = mode_for_size (POINTER_SIZE, MODE_INT, 0);
1580 /* It's hard to see what the mode and size of a function ought to
1581 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1582 make it consistent with that. */
1583 TYPE_MODE (type) = mode_for_size (FUNCTION_BOUNDARY, MODE_INT, 0);
1584 TYPE_SIZE (type) = bitsize_int (FUNCTION_BOUNDARY);
1585 TYPE_SIZE_UNIT (type) = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
1589 case REFERENCE_TYPE:
1592 enum machine_mode mode = ((TREE_CODE (type) == REFERENCE_TYPE
1593 && reference_types_internal)
1594 ? Pmode : TYPE_MODE (type));
1596 int nbits = GET_MODE_BITSIZE (mode);
1598 TYPE_SIZE (type) = bitsize_int (nbits);
1599 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
1600 TYPE_UNSIGNED (type) = 1;
1601 TYPE_PRECISION (type) = nbits;
1607 tree index = TYPE_DOMAIN (type);
1608 tree element = TREE_TYPE (type);
1610 build_pointer_type (element);
1612 /* We need to know both bounds in order to compute the size. */
1613 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
1614 && TYPE_SIZE (element))
1616 tree ub = TYPE_MAX_VALUE (index);
1617 tree lb = TYPE_MIN_VALUE (index);
1621 /* The initial subtraction should happen in the original type so
1622 that (possible) negative values are handled appropriately. */
1623 length = size_binop (PLUS_EXPR, size_one_node,
1625 fold (build (MINUS_EXPR,
1629 /* Special handling for arrays of bits (for Chill). */
1630 element_size = TYPE_SIZE (element);
1631 if (TYPE_PACKED (type) && INTEGRAL_TYPE_P (element)
1632 && (integer_zerop (TYPE_MAX_VALUE (element))
1633 || integer_onep (TYPE_MAX_VALUE (element)))
1634 && host_integerp (TYPE_MIN_VALUE (element), 1))
1636 HOST_WIDE_INT maxvalue
1637 = tree_low_cst (TYPE_MAX_VALUE (element), 1);
1638 HOST_WIDE_INT minvalue
1639 = tree_low_cst (TYPE_MIN_VALUE (element), 1);
1641 if (maxvalue - minvalue == 1
1642 && (maxvalue == 1 || maxvalue == 0))
1643 element_size = integer_one_node;
1646 /* If neither bound is a constant and sizetype is signed, make
1647 sure the size is never negative. We should really do this
1648 if *either* bound is non-constant, but this is the best
1649 compromise between C and Ada. */
1650 if (!TYPE_UNSIGNED (sizetype)
1651 && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST
1652 && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST)
1653 length = size_binop (MAX_EXPR, length, size_zero_node);
1655 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
1656 convert (bitsizetype, length));
1658 /* If we know the size of the element, calculate the total
1659 size directly, rather than do some division thing below.
1660 This optimization helps Fortran assumed-size arrays
1661 (where the size of the array is determined at runtime)
1663 Note that we can't do this in the case where the size of
1664 the elements is one bit since TYPE_SIZE_UNIT cannot be
1665 set correctly in that case. */
1666 if (TYPE_SIZE_UNIT (element) != 0 && ! integer_onep (element_size))
1667 TYPE_SIZE_UNIT (type)
1668 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
1671 /* Now round the alignment and size,
1672 using machine-dependent criteria if any. */
1674 #ifdef ROUND_TYPE_ALIGN
1676 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
1678 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
1680 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
1681 TYPE_MODE (type) = BLKmode;
1682 if (TYPE_SIZE (type) != 0
1683 #ifdef MEMBER_TYPE_FORCES_BLK
1684 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
1686 /* BLKmode elements force BLKmode aggregate;
1687 else extract/store fields may lose. */
1688 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
1689 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
1691 /* One-element arrays get the component type's mode. */
1692 if (simple_cst_equal (TYPE_SIZE (type),
1693 TYPE_SIZE (TREE_TYPE (type))))
1694 TYPE_MODE (type) = TYPE_MODE (TREE_TYPE (type));
1697 = mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1);
1699 if (TYPE_MODE (type) != BLKmode
1700 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
1701 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type))
1702 && TYPE_MODE (type) != BLKmode)
1704 TYPE_NO_FORCE_BLK (type) = 1;
1705 TYPE_MODE (type) = BLKmode;
1713 case QUAL_UNION_TYPE:
1716 record_layout_info rli;
1718 /* Initialize the layout information. */
1719 rli = start_record_layout (type);
1721 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1722 in the reverse order in building the COND_EXPR that denotes
1723 its size. We reverse them again later. */
1724 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1725 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1727 /* Place all the fields. */
1728 for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
1729 place_field (rli, field);
1731 if (TREE_CODE (type) == QUAL_UNION_TYPE)
1732 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
1734 if (lang_adjust_rli)
1735 (*lang_adjust_rli) (rli);
1737 /* Finish laying out the record. */
1738 finish_record_layout (rli, /*free_p=*/true);
1742 case SET_TYPE: /* Used by Chill and Pascal. */
1743 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
1744 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
1748 #ifndef SET_WORD_SIZE
1749 #define SET_WORD_SIZE BITS_PER_WORD
1751 unsigned int alignment
1752 = set_alignment ? set_alignment : SET_WORD_SIZE;
1753 HOST_WIDE_INT size_in_bits
1754 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type)), 0)
1755 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type)), 0) + 1);
1756 HOST_WIDE_INT rounded_size
1757 = ((size_in_bits + alignment - 1) / alignment) * alignment;
1759 if (rounded_size > (int) alignment)
1760 TYPE_MODE (type) = BLKmode;
1762 TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
1764 TYPE_SIZE (type) = bitsize_int (rounded_size);
1765 TYPE_SIZE_UNIT (type) = size_int (rounded_size / BITS_PER_UNIT);
1766 TYPE_ALIGN (type) = alignment;
1767 TYPE_USER_ALIGN (type) = 0;
1768 TYPE_PRECISION (type) = size_in_bits;
1773 /* The size may vary in different languages, so the language front end
1774 should fill in the size. */
1775 TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
1776 TYPE_USER_ALIGN (type) = 0;
1777 TYPE_MODE (type) = BLKmode;
1784 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1785 records and unions, finish_record_layout already called this
1787 if (TREE_CODE (type) != RECORD_TYPE
1788 && TREE_CODE (type) != UNION_TYPE
1789 && TREE_CODE (type) != QUAL_UNION_TYPE)
1790 finalize_type_size (type);
1792 /* If this type is created before sizetype has been permanently set,
1793 record it so set_sizetype can fix it up. */
1795 early_type_list = tree_cons (NULL_TREE, type, early_type_list);
1797 /* If an alias set has been set for this aggregate when it was incomplete,
1798 force it into alias set 0.
1799 This is too conservative, but we cannot call record_component_aliases
1800 here because some frontends still change the aggregates after
1802 if (AGGREGATE_TYPE_P (type) && TYPE_ALIAS_SET_KNOWN_P (type))
1803 TYPE_ALIAS_SET (type) = 0;
1806 /* Create and return a type for signed integers of PRECISION bits. */
1809 make_signed_type (int precision)
1811 tree type = make_node (INTEGER_TYPE);
1813 TYPE_PRECISION (type) = precision;
1815 fixup_signed_type (type);
1819 /* Create and return a type for unsigned integers of PRECISION bits. */
1822 make_unsigned_type (int precision)
1824 tree type = make_node (INTEGER_TYPE);
1826 TYPE_PRECISION (type) = precision;
1828 fixup_unsigned_type (type);
1832 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1833 value to enable integer types to be created. */
1836 initialize_sizetypes (void)
1838 tree t = make_node (INTEGER_TYPE);
1840 /* Set this so we do something reasonable for the build_int_2 calls
1842 integer_type_node = t;
1844 TYPE_MODE (t) = SImode;
1845 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
1846 TYPE_USER_ALIGN (t) = 0;
1847 TYPE_SIZE (t) = build_int_2 (GET_MODE_BITSIZE (SImode), 0);
1848 TYPE_SIZE_UNIT (t) = build_int_2 (GET_MODE_SIZE (SImode), 0);
1849 TYPE_UNSIGNED (t) = 1;
1850 TYPE_PRECISION (t) = GET_MODE_BITSIZE (SImode);
1851 TYPE_MIN_VALUE (t) = build_int_2 (0, 0);
1852 TYPE_IS_SIZETYPE (t) = 1;
1854 /* 1000 avoids problems with possible overflow and is certainly
1855 larger than any size value we'd want to be storing. */
1856 TYPE_MAX_VALUE (t) = build_int_2 (1000, 0);
1858 /* These two must be different nodes because of the caching done in
1861 bitsizetype = copy_node (t);
1862 integer_type_node = 0;
1865 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1866 Also update the type of any standard type's sizes made so far. */
1869 set_sizetype (tree type)
1871 int oprecision = TYPE_PRECISION (type);
1872 /* The *bitsizetype types use a precision that avoids overflows when
1873 calculating signed sizes / offsets in bits. However, when
1874 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1876 int precision = MIN (oprecision + BITS_PER_UNIT_LOG + 1,
1877 2 * HOST_BITS_PER_WIDE_INT);
1884 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1885 sizetype = copy_node (type);
1886 TYPE_ORIG_SIZE_TYPE (sizetype) = type;
1887 TYPE_IS_SIZETYPE (sizetype) = 1;
1888 bitsizetype = make_node (INTEGER_TYPE);
1889 TYPE_NAME (bitsizetype) = TYPE_NAME (type);
1890 TYPE_PRECISION (bitsizetype) = precision;
1891 TYPE_IS_SIZETYPE (bitsizetype) = 1;
1893 if (TYPE_UNSIGNED (type))
1894 fixup_unsigned_type (bitsizetype);
1896 fixup_signed_type (bitsizetype);
1898 layout_type (bitsizetype);
1900 if (TYPE_UNSIGNED (type))
1902 usizetype = sizetype;
1903 ubitsizetype = bitsizetype;
1904 ssizetype = copy_node (make_signed_type (oprecision));
1905 sbitsizetype = copy_node (make_signed_type (precision));
1909 ssizetype = sizetype;
1910 sbitsizetype = bitsizetype;
1911 usizetype = copy_node (make_unsigned_type (oprecision));
1912 ubitsizetype = copy_node (make_unsigned_type (precision));
1915 TYPE_NAME (bitsizetype) = get_identifier ("bit_size_type");
1917 /* Show is a sizetype, is a main type, and has no pointers to it. */
1918 for (i = 0; i < ARRAY_SIZE (sizetype_tab); i++)
1920 TYPE_IS_SIZETYPE (sizetype_tab[i]) = 1;
1921 TYPE_MAIN_VARIANT (sizetype_tab[i]) = sizetype_tab[i];
1922 TYPE_NEXT_VARIANT (sizetype_tab[i]) = 0;
1923 TYPE_POINTER_TO (sizetype_tab[i]) = 0;
1924 TYPE_REFERENCE_TO (sizetype_tab[i]) = 0;
1927 /* Go down each of the types we already made and set the proper type
1928 for the sizes in them. */
1929 for (t = early_type_list; t != 0; t = TREE_CHAIN (t))
1931 if (TREE_CODE (TREE_VALUE (t)) != INTEGER_TYPE
1932 && TREE_CODE (TREE_VALUE (t)) != BOOLEAN_TYPE)
1935 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t))) = bitsizetype;
1936 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t))) = sizetype;
1939 early_type_list = 0;
1943 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1944 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1945 for TYPE, based on the PRECISION and whether or not the TYPE
1946 IS_UNSIGNED. PRECISION need not correspond to a width supported
1947 natively by the hardware; for example, on a machine with 8-bit,
1948 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1952 set_min_and_max_values_for_integral_type (tree type,
1961 min_value = build_int_2 (0, 0);
1963 = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
1964 ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
1965 precision - HOST_BITS_PER_WIDE_INT > 0
1966 ? ((unsigned HOST_WIDE_INT) ~0
1967 >> (HOST_BITS_PER_WIDE_INT
1968 - (precision - HOST_BITS_PER_WIDE_INT)))
1974 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1975 ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
1976 (((HOST_WIDE_INT) (-1)
1977 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1978 ? precision - HOST_BITS_PER_WIDE_INT - 1
1981 = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
1982 ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
1983 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
1984 ? (((HOST_WIDE_INT) 1
1985 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
1989 TREE_TYPE (min_value) = type;
1990 TREE_TYPE (max_value) = type;
1991 TYPE_MIN_VALUE (type) = min_value;
1992 TYPE_MAX_VALUE (type) = max_value;
1995 /* Set the extreme values of TYPE based on its precision in bits,
1996 then lay it out. Used when make_signed_type won't do
1997 because the tree code is not INTEGER_TYPE.
1998 E.g. for Pascal, when the -fsigned-char option is given. */
2001 fixup_signed_type (tree type)
2003 int precision = TYPE_PRECISION (type);
2005 /* We can not represent properly constants greater then
2006 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2007 as they are used by i386 vector extensions and friends. */
2008 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2009 precision = HOST_BITS_PER_WIDE_INT * 2;
2011 set_min_and_max_values_for_integral_type (type, precision,
2012 /*is_unsigned=*/false);
2014 /* Lay out the type: set its alignment, size, etc. */
2018 /* Set the extreme values of TYPE based on its precision in bits,
2019 then lay it out. This is used both in `make_unsigned_type'
2020 and for enumeral types. */
2023 fixup_unsigned_type (tree type)
2025 int precision = TYPE_PRECISION (type);
2027 /* We can not represent properly constants greater then
2028 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2029 as they are used by i386 vector extensions and friends. */
2030 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2031 precision = HOST_BITS_PER_WIDE_INT * 2;
2033 set_min_and_max_values_for_integral_type (type, precision,
2034 /*is_unsigned=*/true);
2036 /* Lay out the type: set its alignment, size, etc. */
2040 /* Find the best machine mode to use when referencing a bit field of length
2041 BITSIZE bits starting at BITPOS.
2043 The underlying object is known to be aligned to a boundary of ALIGN bits.
2044 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2045 larger than LARGEST_MODE (usually SImode).
2047 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2048 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2049 mode meeting these conditions.
2051 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2052 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2053 all the conditions. */
2056 get_best_mode (int bitsize, int bitpos, unsigned int align,
2057 enum machine_mode largest_mode, int volatilep)
2059 enum machine_mode mode;
2060 unsigned int unit = 0;
2062 /* Find the narrowest integer mode that contains the bit field. */
2063 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2064 mode = GET_MODE_WIDER_MODE (mode))
2066 unit = GET_MODE_BITSIZE (mode);
2067 if ((bitpos % unit) + bitsize <= unit)
2071 if (mode == VOIDmode
2072 /* It is tempting to omit the following line
2073 if STRICT_ALIGNMENT is true.
2074 But that is incorrect, since if the bitfield uses part of 3 bytes
2075 and we use a 4-byte mode, we could get a spurious segv
2076 if the extra 4th byte is past the end of memory.
2077 (Though at least one Unix compiler ignores this problem:
2078 that on the Sequent 386 machine. */
2079 || MIN (unit, BIGGEST_ALIGNMENT) > align
2080 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2083 if (SLOW_BYTE_ACCESS && ! volatilep)
2085 enum machine_mode wide_mode = VOIDmode, tmode;
2087 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2088 tmode = GET_MODE_WIDER_MODE (tmode))
2090 unit = GET_MODE_BITSIZE (tmode);
2091 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2092 && unit <= BITS_PER_WORD
2093 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2094 && (largest_mode == VOIDmode
2095 || unit <= GET_MODE_BITSIZE (largest_mode)))
2099 if (wide_mode != VOIDmode)
2106 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2110 get_mode_bounds (enum machine_mode mode, int sign, rtx *mmin, rtx *mmax)
2112 int size = GET_MODE_BITSIZE (mode);
2114 if (size > HOST_BITS_PER_WIDE_INT)
2119 *mmin = GEN_INT (-((unsigned HOST_WIDE_INT) 1 << (size - 1)));
2120 *mmax = GEN_INT (((unsigned HOST_WIDE_INT) 1 << (size - 1)) - 1);
2125 *mmax = GEN_INT (((unsigned HOST_WIDE_INT) 1 << (size - 1) << 1) - 1);
2129 #include "gt-stor-layout.h"