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"
39 /* Set to one when set_sizetype has been called. */
40 static int sizetype_set
;
42 /* List of types created before set_sizetype has been called. We do not
43 make this a GGC root since we want these nodes to be reclaimed. */
44 static tree early_type_list
;
46 /* Data type for the expressions representing sizes of data types.
47 It is the first integer type laid out. */
48 tree sizetype_tab
[(int) TYPE_KIND_LAST
];
50 /* If nonzero, this is an upper limit on alignment of structure fields.
51 The value is measured in bits. */
52 unsigned int maximum_field_alignment
;
54 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
55 May be overridden by front-ends. */
56 unsigned int set_alignment
= 0;
58 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
59 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
60 called only by a front end. */
61 static int reference_types_internal
= 0;
63 static void finalize_record_size (record_layout_info
);
64 static void finalize_type_size (tree
);
65 static void place_union_field (record_layout_info
, tree
);
66 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
67 static int excess_unit_span (HOST_WIDE_INT
, HOST_WIDE_INT
, HOST_WIDE_INT
,
70 extern void debug_rli (record_layout_info
);
72 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
74 static GTY(()) tree pending_sizes
;
76 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
80 internal_reference_types (void)
82 reference_types_internal
= 1;
85 /* Get a list of all the objects put on the pending sizes list. */
88 get_pending_sizes (void)
90 tree chain
= pending_sizes
;
96 /* Add EXPR to the pending sizes list. */
99 put_pending_size (tree expr
)
101 /* Strip any simple arithmetic from EXPR to see if it has an underlying
103 expr
= skip_simple_arithmetic (expr
);
105 if (TREE_CODE (expr
) == SAVE_EXPR
)
106 pending_sizes
= tree_cons (NULL_TREE
, expr
, pending_sizes
);
109 /* Put a chain of objects into the pending sizes list, which must be
113 put_pending_sizes (tree chain
)
118 pending_sizes
= chain
;
121 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
122 to serve as the actual size-expression for a type or decl. */
125 variable_size (tree size
)
129 /* If the language-processor is to take responsibility for variable-sized
130 items (e.g., languages which have elaboration procedures like Ada),
131 just return SIZE unchanged. Likewise for self-referential sizes and
133 if (TREE_CONSTANT (size
)
134 || lang_hooks
.decls
.global_bindings_p () < 0
135 || CONTAINS_PLACEHOLDER_P (size
))
138 size
= save_expr (size
);
140 /* If an array with a variable number of elements is declared, and
141 the elements require destruction, we will emit a cleanup for the
142 array. That cleanup is run both on normal exit from the block
143 and in the exception-handler for the block. Normally, when code
144 is used in both ordinary code and in an exception handler it is
145 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
146 not wish to do that here; the array-size is the same in both
148 save
= skip_simple_arithmetic (size
);
150 if (cfun
&& cfun
->x_dont_save_pending_sizes_p
)
151 /* The front-end doesn't want us to keep a list of the expressions
152 that determine sizes for variable size objects. Trust it. */
155 if (lang_hooks
.decls
.global_bindings_p ())
157 if (TREE_CONSTANT (size
))
158 error ("type size can't be explicitly evaluated");
160 error ("variable-size type declared outside of any function");
162 return size_one_node
;
165 put_pending_size (save
);
170 #ifndef MAX_FIXED_MODE_SIZE
171 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
174 /* Return the machine mode to use for a nonscalar of SIZE bits. The
175 mode must be in class CLASS, and have exactly that many value bits;
176 it may have padding as well. If LIMIT is nonzero, modes of wider
177 than MAX_FIXED_MODE_SIZE will not be used. */
180 mode_for_size (unsigned int size
, enum mode_class
class, int limit
)
182 enum machine_mode mode
;
184 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
187 /* Get the first mode which has this size, in the specified class. */
188 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
189 mode
= GET_MODE_WIDER_MODE (mode
))
190 if (GET_MODE_PRECISION (mode
) == size
)
196 /* Similar, except passed a tree node. */
199 mode_for_size_tree (tree size
, enum mode_class
class, int limit
)
201 if (TREE_CODE (size
) != INTEGER_CST
202 || TREE_OVERFLOW (size
)
203 /* What we really want to say here is that the size can fit in a
204 host integer, but we know there's no way we'd find a mode for
205 this many bits, so there's no point in doing the precise test. */
206 || compare_tree_int (size
, 1000) > 0)
209 return mode_for_size (tree_low_cst (size
, 1), class, limit
);
212 /* Similar, but never return BLKmode; return the narrowest mode that
213 contains at least the requested number of value bits. */
216 smallest_mode_for_size (unsigned int size
, enum mode_class
class)
218 enum machine_mode mode
;
220 /* Get the first mode which has at least this size, in the
222 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
223 mode
= GET_MODE_WIDER_MODE (mode
))
224 if (GET_MODE_PRECISION (mode
) >= size
)
230 /* Find an integer mode of the exact same size, or BLKmode on failure. */
233 int_mode_for_mode (enum machine_mode mode
)
235 switch (GET_MODE_CLASS (mode
))
238 case MODE_PARTIAL_INT
:
241 case MODE_COMPLEX_INT
:
242 case MODE_COMPLEX_FLOAT
:
244 case MODE_VECTOR_INT
:
245 case MODE_VECTOR_FLOAT
:
246 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
253 /* ... fall through ... */
263 /* Return the alignment of MODE. This will be bounded by 1 and
264 BIGGEST_ALIGNMENT. */
267 get_mode_alignment (enum machine_mode mode
)
269 return MIN (BIGGEST_ALIGNMENT
, MAX (1, mode_base_align
[mode
]*BITS_PER_UNIT
));
273 /* Subroutine of layout_decl: Force alignment required for the data type.
274 But if the decl itself wants greater alignment, don't override that. */
277 do_type_align (tree type
, tree decl
)
279 if (TYPE_ALIGN (type
) > DECL_ALIGN (decl
))
281 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
282 if (TREE_CODE (decl
) == FIELD_DECL
)
283 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
287 /* Set the size, mode and alignment of a ..._DECL node.
288 TYPE_DECL does need this for C++.
289 Note that LABEL_DECL and CONST_DECL nodes do not need this,
290 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
291 Don't call layout_decl for them.
293 KNOWN_ALIGN is the amount of alignment we can assume this
294 decl has with no special effort. It is relevant only for FIELD_DECLs
295 and depends on the previous fields.
296 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
297 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
298 the record will be aligned to suit. */
301 layout_decl (tree decl
, unsigned int known_align
)
303 tree type
= TREE_TYPE (decl
);
304 enum tree_code code
= TREE_CODE (decl
);
307 if (code
== CONST_DECL
)
309 else if (code
!= VAR_DECL
&& code
!= PARM_DECL
&& code
!= RESULT_DECL
310 && code
!= TYPE_DECL
&& code
!= FIELD_DECL
)
313 rtl
= DECL_RTL_IF_SET (decl
);
315 if (type
== error_mark_node
)
316 type
= void_type_node
;
318 /* Usually the size and mode come from the data type without change,
319 however, the front-end may set the explicit width of the field, so its
320 size may not be the same as the size of its type. This happens with
321 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
322 also happens with other fields. For example, the C++ front-end creates
323 zero-sized fields corresponding to empty base classes, and depends on
324 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
325 size in bytes from the size in bits. If we have already set the mode,
326 don't set it again since we can be called twice for FIELD_DECLs. */
328 DECL_UNSIGNED (decl
) = TYPE_UNSIGNED (type
);
329 if (DECL_MODE (decl
) == VOIDmode
)
330 DECL_MODE (decl
) = TYPE_MODE (type
);
332 if (DECL_SIZE (decl
) == 0)
334 DECL_SIZE (decl
) = TYPE_SIZE (type
);
335 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
337 else if (DECL_SIZE_UNIT (decl
) == 0)
338 DECL_SIZE_UNIT (decl
)
339 = convert (sizetype
, size_binop (CEIL_DIV_EXPR
, DECL_SIZE (decl
),
342 if (code
!= FIELD_DECL
)
343 /* For non-fields, update the alignment from the type. */
344 do_type_align (type
, decl
);
346 /* For fields, it's a bit more complicated... */
348 bool old_user_align
= DECL_USER_ALIGN (decl
);
350 if (DECL_BIT_FIELD (decl
))
352 DECL_BIT_FIELD_TYPE (decl
) = type
;
354 /* A zero-length bit-field affects the alignment of the next
356 if (integer_zerop (DECL_SIZE (decl
))
357 && ! DECL_PACKED (decl
)
358 && ! targetm
.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl
)))
360 #ifdef PCC_BITFIELD_TYPE_MATTERS
361 if (PCC_BITFIELD_TYPE_MATTERS
)
362 do_type_align (type
, decl
);
366 #ifdef EMPTY_FIELD_BOUNDARY
367 if (EMPTY_FIELD_BOUNDARY
> DECL_ALIGN (decl
))
369 DECL_ALIGN (decl
) = EMPTY_FIELD_BOUNDARY
;
370 DECL_USER_ALIGN (decl
) = 0;
376 /* See if we can use an ordinary integer mode for a bit-field.
377 Conditions are: a fixed size that is correct for another mode
378 and occupying a complete byte or bytes on proper boundary. */
379 if (TYPE_SIZE (type
) != 0
380 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
381 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
)
383 enum machine_mode xmode
384 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
388 || known_align
>= GET_MODE_ALIGNMENT (xmode
)))
390 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
392 DECL_MODE (decl
) = xmode
;
393 DECL_BIT_FIELD (decl
) = 0;
397 /* Turn off DECL_BIT_FIELD if we won't need it set. */
398 if (TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
399 && known_align
>= TYPE_ALIGN (type
)
400 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
))
401 DECL_BIT_FIELD (decl
) = 0;
403 else if (DECL_PACKED (decl
) && DECL_USER_ALIGN (decl
))
404 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
405 round up; we'll reduce it again below. We want packing to
406 supersede USER_ALIGN inherited from the type, but defer to
407 alignment explicitly specified on the field decl. */;
409 do_type_align (type
, decl
);
411 /* If the field is of variable size, we can't misalign it since we
412 have no way to make a temporary to align the result. But this
413 isn't an issue if the decl is not addressable. Likewise if it
416 Note that do_type_align may set DECL_USER_ALIGN, so we need to
417 check old_user_align instead. */
418 if (DECL_PACKED (decl
)
420 && (DECL_NONADDRESSABLE_P (decl
)
421 || DECL_SIZE_UNIT (decl
) == 0
422 || TREE_CODE (DECL_SIZE_UNIT (decl
)) == INTEGER_CST
))
423 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
425 if (! DECL_USER_ALIGN (decl
) && ! DECL_PACKED (decl
))
427 /* Some targets (i.e. i386, VMS) limit struct field alignment
428 to a lower boundary than alignment of variables unless
429 it was overridden by attribute aligned. */
430 #ifdef BIGGEST_FIELD_ALIGNMENT
432 = MIN (DECL_ALIGN (decl
), (unsigned) BIGGEST_FIELD_ALIGNMENT
);
434 #ifdef ADJUST_FIELD_ALIGN
435 DECL_ALIGN (decl
) = ADJUST_FIELD_ALIGN (decl
, DECL_ALIGN (decl
));
439 /* Should this be controlled by DECL_USER_ALIGN, too? */
440 if (maximum_field_alignment
!= 0)
441 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), maximum_field_alignment
);
444 /* Evaluate nonconstant size only once, either now or as soon as safe. */
445 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
446 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
447 if (DECL_SIZE_UNIT (decl
) != 0
448 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
449 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
451 /* If requested, warn about definitions of large data objects. */
453 && (code
== VAR_DECL
|| code
== PARM_DECL
)
454 && ! DECL_EXTERNAL (decl
))
456 tree size
= DECL_SIZE_UNIT (decl
);
458 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
459 && compare_tree_int (size
, larger_than_size
) > 0)
461 int size_as_int
= TREE_INT_CST_LOW (size
);
463 if (compare_tree_int (size
, size_as_int
) == 0)
464 warning ("%Jsize of '%D' is %d bytes", decl
, decl
, size_as_int
);
466 warning ("%Jsize of '%D' is larger than %d bytes",
467 decl
, decl
, larger_than_size
);
471 /* If the RTL was already set, update its mode and mem attributes. */
474 PUT_MODE (rtl
, DECL_MODE (decl
));
475 SET_DECL_RTL (decl
, 0);
476 set_mem_attributes (rtl
, decl
, 1);
477 SET_DECL_RTL (decl
, rtl
);
481 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
482 a previous call to layout_decl and calls it again. */
485 relayout_decl (tree decl
)
487 DECL_SIZE (decl
) = DECL_SIZE_UNIT (decl
) = 0;
488 DECL_MODE (decl
) = VOIDmode
;
489 DECL_ALIGN (decl
) = 0;
490 SET_DECL_RTL (decl
, 0);
492 layout_decl (decl
, 0);
495 /* Hook for a front-end function that can modify the record layout as needed
496 immediately before it is finalized. */
498 void (*lang_adjust_rli
) (record_layout_info
) = 0;
501 set_lang_adjust_rli (void (*f
) (record_layout_info
))
506 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
507 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
508 is to be passed to all other layout functions for this record. It is the
509 responsibility of the caller to call `free' for the storage returned.
510 Note that garbage collection is not permitted until we finish laying
514 start_record_layout (tree t
)
516 record_layout_info rli
= xmalloc (sizeof (struct record_layout_info_s
));
520 /* If the type has a minimum specified alignment (via an attribute
521 declaration, for example) use it -- otherwise, start with a
522 one-byte alignment. */
523 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
524 rli
->unpacked_align
= rli
->record_align
;
525 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
527 #ifdef STRUCTURE_SIZE_BOUNDARY
528 /* Packed structures don't need to have minimum size. */
529 if (! TYPE_PACKED (t
))
530 rli
->record_align
= MAX (rli
->record_align
, (unsigned) STRUCTURE_SIZE_BOUNDARY
);
533 rli
->offset
= size_zero_node
;
534 rli
->bitpos
= bitsize_zero_node
;
536 rli
->pending_statics
= 0;
537 rli
->packed_maybe_necessary
= 0;
542 /* These four routines perform computations that convert between
543 the offset/bitpos forms and byte and bit offsets. */
546 bit_from_pos (tree offset
, tree bitpos
)
548 return size_binop (PLUS_EXPR
, bitpos
,
549 size_binop (MULT_EXPR
, convert (bitsizetype
, offset
),
554 byte_from_pos (tree offset
, tree bitpos
)
556 return size_binop (PLUS_EXPR
, offset
,
558 size_binop (TRUNC_DIV_EXPR
, bitpos
,
559 bitsize_unit_node
)));
563 pos_from_bit (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
,
566 *poffset
= size_binop (MULT_EXPR
,
568 size_binop (FLOOR_DIV_EXPR
, pos
,
569 bitsize_int (off_align
))),
570 size_int (off_align
/ BITS_PER_UNIT
));
571 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
574 /* Given a pointer to bit and byte offsets and an offset alignment,
575 normalize the offsets so they are within the alignment. */
578 normalize_offset (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
)
580 /* If the bit position is now larger than it should be, adjust it
582 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
584 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
585 bitsize_int (off_align
));
588 = size_binop (PLUS_EXPR
, *poffset
,
589 size_binop (MULT_EXPR
, convert (sizetype
, extra_aligns
),
590 size_int (off_align
/ BITS_PER_UNIT
)));
593 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
597 /* Print debugging information about the information in RLI. */
600 debug_rli (record_layout_info rli
)
602 print_node_brief (stderr
, "type", rli
->t
, 0);
603 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
604 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
606 fprintf (stderr
, "\naligns: rec = %u, unpack = %u, off = %u\n",
607 rli
->record_align
, rli
->unpacked_align
,
609 if (rli
->packed_maybe_necessary
)
610 fprintf (stderr
, "packed may be necessary\n");
612 if (rli
->pending_statics
)
614 fprintf (stderr
, "pending statics:\n");
615 debug_tree (rli
->pending_statics
);
619 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
620 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
623 normalize_rli (record_layout_info rli
)
625 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
628 /* Returns the size in bytes allocated so far. */
631 rli_size_unit_so_far (record_layout_info rli
)
633 return byte_from_pos (rli
->offset
, rli
->bitpos
);
636 /* Returns the size in bits allocated so far. */
639 rli_size_so_far (record_layout_info rli
)
641 return bit_from_pos (rli
->offset
, rli
->bitpos
);
644 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
645 the next available location is given by KNOWN_ALIGN. Update the
646 variable alignment fields in RLI, and return the alignment to give
650 update_alignment_for_field (record_layout_info rli
, tree field
,
651 unsigned int known_align
)
653 /* The alignment required for FIELD. */
654 unsigned int desired_align
;
655 /* The type of this field. */
656 tree type
= TREE_TYPE (field
);
657 /* True if the field was explicitly aligned by the user. */
661 /* Lay out the field so we know what alignment it needs. */
662 layout_decl (field
, known_align
);
663 desired_align
= DECL_ALIGN (field
);
664 user_align
= DECL_USER_ALIGN (field
);
666 is_bitfield
= (type
!= error_mark_node
667 && DECL_BIT_FIELD_TYPE (field
)
668 && ! integer_zerop (TYPE_SIZE (type
)));
670 /* Record must have at least as much alignment as any field.
671 Otherwise, the alignment of the field within the record is
673 if (is_bitfield
&& targetm
.ms_bitfield_layout_p (rli
->t
))
675 /* Here, the alignment of the underlying type of a bitfield can
676 affect the alignment of a record; even a zero-sized field
677 can do this. The alignment should be to the alignment of
678 the type, except that for zero-size bitfields this only
679 applies if there was an immediately prior, nonzero-size
680 bitfield. (That's the way it is, experimentally.) */
681 if (! integer_zerop (DECL_SIZE (field
))
682 ? ! DECL_PACKED (field
)
684 && DECL_BIT_FIELD_TYPE (rli
->prev_field
)
685 && ! integer_zerop (DECL_SIZE (rli
->prev_field
))))
687 unsigned int type_align
= TYPE_ALIGN (type
);
688 type_align
= MAX (type_align
, desired_align
);
689 if (maximum_field_alignment
!= 0)
690 type_align
= MIN (type_align
, maximum_field_alignment
);
691 rli
->record_align
= MAX (rli
->record_align
, type_align
);
692 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
695 #ifdef PCC_BITFIELD_TYPE_MATTERS
696 else if (is_bitfield
&& PCC_BITFIELD_TYPE_MATTERS
)
698 /* Named bit-fields cause the entire structure to have the
699 alignment implied by their type. Some targets also apply the same
700 rules to unnamed bitfields. */
701 if (DECL_NAME (field
) != 0
702 || targetm
.align_anon_bitfield ())
704 unsigned int type_align
= TYPE_ALIGN (type
);
706 #ifdef ADJUST_FIELD_ALIGN
707 if (! TYPE_USER_ALIGN (type
))
708 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
711 if (maximum_field_alignment
!= 0)
712 type_align
= MIN (type_align
, maximum_field_alignment
);
713 else if (DECL_PACKED (field
))
714 type_align
= MIN (type_align
, BITS_PER_UNIT
);
716 /* The alignment of the record is increased to the maximum
717 of the current alignment, the alignment indicated on the
718 field (i.e., the alignment specified by an __aligned__
719 attribute), and the alignment indicated by the type of
721 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
722 rli
->record_align
= MAX (rli
->record_align
, type_align
);
725 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
726 user_align
|= TYPE_USER_ALIGN (type
);
732 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
733 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
736 TYPE_USER_ALIGN (rli
->t
) |= user_align
;
738 return desired_align
;
741 /* Called from place_field to handle unions. */
744 place_union_field (record_layout_info rli
, tree field
)
746 update_alignment_for_field (rli
, field
, /*known_align=*/0);
748 DECL_FIELD_OFFSET (field
) = size_zero_node
;
749 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
750 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
752 /* We assume the union's size will be a multiple of a byte so we don't
753 bother with BITPOS. */
754 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
755 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
756 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
757 rli
->offset
= fold (build3 (COND_EXPR
, sizetype
,
758 DECL_QUALIFIER (field
),
759 DECL_SIZE_UNIT (field
), rli
->offset
));
762 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
763 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
764 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
765 units of alignment than the underlying TYPE. */
767 excess_unit_span (HOST_WIDE_INT byte_offset
, HOST_WIDE_INT bit_offset
,
768 HOST_WIDE_INT size
, HOST_WIDE_INT align
, tree type
)
770 /* Note that the calculation of OFFSET might overflow; we calculate it so
771 that we still get the right result as long as ALIGN is a power of two. */
772 unsigned HOST_WIDE_INT offset
= byte_offset
* BITS_PER_UNIT
+ bit_offset
;
774 offset
= offset
% align
;
775 return ((offset
+ size
+ align
- 1) / align
776 > ((unsigned HOST_WIDE_INT
) tree_low_cst (TYPE_SIZE (type
), 1)
781 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
782 is a FIELD_DECL to be added after those fields already present in
783 T. (FIELD is not actually added to the TYPE_FIELDS list here;
784 callers that desire that behavior must manually perform that step.) */
787 place_field (record_layout_info rli
, tree field
)
789 /* The alignment required for FIELD. */
790 unsigned int desired_align
;
791 /* The alignment FIELD would have if we just dropped it into the
792 record as it presently stands. */
793 unsigned int known_align
;
794 unsigned int actual_align
;
795 /* The type of this field. */
796 tree type
= TREE_TYPE (field
);
798 if (TREE_CODE (field
) == ERROR_MARK
|| TREE_CODE (type
) == ERROR_MARK
)
801 /* If FIELD is static, then treat it like a separate variable, not
802 really like a structure field. If it is a FUNCTION_DECL, it's a
803 method. In both cases, all we do is lay out the decl, and we do
804 it *after* the record is laid out. */
805 if (TREE_CODE (field
) == VAR_DECL
)
807 rli
->pending_statics
= tree_cons (NULL_TREE
, field
,
808 rli
->pending_statics
);
812 /* Enumerators and enum types which are local to this class need not
813 be laid out. Likewise for initialized constant fields. */
814 else if (TREE_CODE (field
) != FIELD_DECL
)
817 /* Unions are laid out very differently than records, so split
818 that code off to another function. */
819 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
821 place_union_field (rli
, field
);
825 /* Work out the known alignment so far. Note that A & (-A) is the
826 value of the least-significant bit in A that is one. */
827 if (! integer_zerop (rli
->bitpos
))
828 known_align
= (tree_low_cst (rli
->bitpos
, 1)
829 & - tree_low_cst (rli
->bitpos
, 1));
830 else if (integer_zerop (rli
->offset
))
831 known_align
= BIGGEST_ALIGNMENT
;
832 else if (host_integerp (rli
->offset
, 1))
833 known_align
= (BITS_PER_UNIT
834 * (tree_low_cst (rli
->offset
, 1)
835 & - tree_low_cst (rli
->offset
, 1)));
837 known_align
= rli
->offset_align
;
839 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
841 if (warn_packed
&& DECL_PACKED (field
))
843 if (known_align
>= TYPE_ALIGN (type
))
845 if (TYPE_ALIGN (type
) > desired_align
)
847 if (STRICT_ALIGNMENT
)
848 warning ("%Jpacked attribute causes inefficient alignment "
849 "for '%D'", field
, field
);
851 warning ("%Jpacked attribute is unnecessary for '%D'",
856 rli
->packed_maybe_necessary
= 1;
859 /* Does this field automatically have alignment it needs by virtue
860 of the fields that precede it and the record's own alignment? */
861 if (known_align
< desired_align
)
863 /* No, we need to skip space before this field.
864 Bump the cumulative size to multiple of field alignment. */
867 warning ("%Jpadding struct to align '%D'", field
, field
);
869 /* If the alignment is still within offset_align, just align
871 if (desired_align
< rli
->offset_align
)
872 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
875 /* First adjust OFFSET by the partial bits, then align. */
877 = size_binop (PLUS_EXPR
, rli
->offset
,
879 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
880 bitsize_unit_node
)));
881 rli
->bitpos
= bitsize_zero_node
;
883 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
886 if (! TREE_CONSTANT (rli
->offset
))
887 rli
->offset_align
= desired_align
;
891 /* Handle compatibility with PCC. Note that if the record has any
892 variable-sized fields, we need not worry about compatibility. */
893 #ifdef PCC_BITFIELD_TYPE_MATTERS
894 if (PCC_BITFIELD_TYPE_MATTERS
895 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
896 && TREE_CODE (field
) == FIELD_DECL
897 && type
!= error_mark_node
898 && DECL_BIT_FIELD (field
)
899 && ! DECL_PACKED (field
)
900 && maximum_field_alignment
== 0
901 && ! integer_zerop (DECL_SIZE (field
))
902 && host_integerp (DECL_SIZE (field
), 1)
903 && host_integerp (rli
->offset
, 1)
904 && host_integerp (TYPE_SIZE (type
), 1))
906 unsigned int type_align
= TYPE_ALIGN (type
);
907 tree dsize
= DECL_SIZE (field
);
908 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
909 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
910 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
912 #ifdef ADJUST_FIELD_ALIGN
913 if (! TYPE_USER_ALIGN (type
))
914 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
917 /* A bit field may not span more units of alignment of its type
918 than its type itself. Advance to next boundary if necessary. */
919 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
920 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
922 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
926 #ifdef BITFIELD_NBYTES_LIMITED
927 if (BITFIELD_NBYTES_LIMITED
928 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
929 && TREE_CODE (field
) == FIELD_DECL
930 && type
!= error_mark_node
931 && DECL_BIT_FIELD_TYPE (field
)
932 && ! DECL_PACKED (field
)
933 && ! integer_zerop (DECL_SIZE (field
))
934 && host_integerp (DECL_SIZE (field
), 1)
935 && host_integerp (rli
->offset
, 1)
936 && host_integerp (TYPE_SIZE (type
), 1))
938 unsigned int type_align
= TYPE_ALIGN (type
);
939 tree dsize
= DECL_SIZE (field
);
940 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
941 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
942 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
944 #ifdef ADJUST_FIELD_ALIGN
945 if (! TYPE_USER_ALIGN (type
))
946 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
949 if (maximum_field_alignment
!= 0)
950 type_align
= MIN (type_align
, maximum_field_alignment
);
951 /* ??? This test is opposite the test in the containing if
952 statement, so this code is unreachable currently. */
953 else if (DECL_PACKED (field
))
954 type_align
= MIN (type_align
, BITS_PER_UNIT
);
956 /* A bit field may not span the unit of alignment of its type.
957 Advance to next boundary if necessary. */
958 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
959 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
961 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
965 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
967 When a bit field is inserted into a packed record, the whole
968 size of the underlying type is used by one or more same-size
969 adjacent bitfields. (That is, if its long:3, 32 bits is
970 used in the record, and any additional adjacent long bitfields are
971 packed into the same chunk of 32 bits. However, if the size
972 changes, a new field of that size is allocated.) In an unpacked
973 record, this is the same as using alignment, but not equivalent
976 Note: for compatibility, we use the type size, not the type alignment
977 to determine alignment, since that matches the documentation */
979 if (targetm
.ms_bitfield_layout_p (rli
->t
)
980 && ((DECL_BIT_FIELD_TYPE (field
) && ! DECL_PACKED (field
))
981 || (rli
->prev_field
&& ! DECL_PACKED (rli
->prev_field
))))
983 /* At this point, either the prior or current are bitfields,
984 (possibly both), and we're dealing with MS packing. */
985 tree prev_saved
= rli
->prev_field
;
987 /* Is the prior field a bitfield? If so, handle "runs" of same
989 if (rli
->prev_field
/* necessarily a bitfield if it exists. */)
991 /* If both are bitfields, nonzero, and the same size, this is
992 the middle of a run. Zero declared size fields are special
993 and handled as "end of run". (Note: it's nonzero declared
994 size, but equal type sizes!) (Since we know that both
995 the current and previous fields are bitfields by the
996 time we check it, DECL_SIZE must be present for both.) */
997 if (DECL_BIT_FIELD_TYPE (field
)
998 && !integer_zerop (DECL_SIZE (field
))
999 && !integer_zerop (DECL_SIZE (rli
->prev_field
))
1000 && host_integerp (DECL_SIZE (rli
->prev_field
), 0)
1001 && host_integerp (TYPE_SIZE (type
), 0)
1002 && simple_cst_equal (TYPE_SIZE (type
),
1003 TYPE_SIZE (TREE_TYPE (rli
->prev_field
))))
1005 /* We're in the middle of a run of equal type size fields; make
1006 sure we realign if we run out of bits. (Not decl size,
1008 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 0);
1010 if (rli
->remaining_in_alignment
< bitsize
)
1012 /* out of bits; bump up to next 'word'. */
1013 rli
->offset
= DECL_FIELD_OFFSET (rli
->prev_field
);
1015 = size_binop (PLUS_EXPR
, TYPE_SIZE (type
),
1016 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1017 rli
->prev_field
= field
;
1018 rli
->remaining_in_alignment
1019 = tree_low_cst (TYPE_SIZE (type
), 0);
1022 rli
->remaining_in_alignment
-= bitsize
;
1026 /* End of a run: if leaving a run of bitfields of the same type
1027 size, we have to "use up" the rest of the bits of the type
1030 Compute the new position as the sum of the size for the prior
1031 type and where we first started working on that type.
1032 Note: since the beginning of the field was aligned then
1033 of course the end will be too. No round needed. */
1035 if (!integer_zerop (DECL_SIZE (rli
->prev_field
)))
1037 tree type_size
= TYPE_SIZE (TREE_TYPE (rli
->prev_field
));
1040 = size_binop (PLUS_EXPR
, type_size
,
1041 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1044 /* We "use up" size zero fields; the code below should behave
1045 as if the prior field was not a bitfield. */
1048 /* Cause a new bitfield to be captured, either this time (if
1049 currently a bitfield) or next time we see one. */
1050 if (!DECL_BIT_FIELD_TYPE(field
)
1051 || integer_zerop (DECL_SIZE (field
)))
1052 rli
->prev_field
= NULL
;
1055 normalize_rli (rli
);
1058 /* If we're starting a new run of same size type bitfields
1059 (or a run of non-bitfields), set up the "first of the run"
1062 That is, if the current field is not a bitfield, or if there
1063 was a prior bitfield the type sizes differ, or if there wasn't
1064 a prior bitfield the size of the current field is nonzero.
1066 Note: we must be sure to test ONLY the type size if there was
1067 a prior bitfield and ONLY for the current field being zero if
1070 if (!DECL_BIT_FIELD_TYPE (field
)
1071 || ( prev_saved
!= NULL
1072 ? !simple_cst_equal (TYPE_SIZE (type
),
1073 TYPE_SIZE (TREE_TYPE (prev_saved
)))
1074 : !integer_zerop (DECL_SIZE (field
)) ))
1076 /* Never smaller than a byte for compatibility. */
1077 unsigned int type_align
= BITS_PER_UNIT
;
1079 /* (When not a bitfield), we could be seeing a flex array (with
1080 no DECL_SIZE). Since we won't be using remaining_in_alignment
1081 until we see a bitfield (and come by here again) we just skip
1083 if (DECL_SIZE (field
) != NULL
1084 && host_integerp (TYPE_SIZE (TREE_TYPE (field
)), 0)
1085 && host_integerp (DECL_SIZE (field
), 0))
1086 rli
->remaining_in_alignment
1087 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field
)), 0)
1088 - tree_low_cst (DECL_SIZE (field
), 0);
1090 /* Now align (conventionally) for the new type. */
1091 if (!DECL_PACKED(field
))
1092 type_align
= MAX(TYPE_ALIGN (type
), type_align
);
1095 && DECL_BIT_FIELD_TYPE (prev_saved
)
1096 /* If the previous bit-field is zero-sized, we've already
1097 accounted for its alignment needs (or ignored it, if
1098 appropriate) while placing it. */
1099 && ! integer_zerop (DECL_SIZE (prev_saved
)))
1100 type_align
= MAX (type_align
,
1101 TYPE_ALIGN (TREE_TYPE (prev_saved
)));
1103 if (maximum_field_alignment
!= 0)
1104 type_align
= MIN (type_align
, maximum_field_alignment
);
1106 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1108 /* If we really aligned, don't allow subsequent bitfields
1110 rli
->prev_field
= NULL
;
1114 /* Offset so far becomes the position of this field after normalizing. */
1115 normalize_rli (rli
);
1116 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1117 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1118 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1120 /* If this field ended up more aligned than we thought it would be (we
1121 approximate this by seeing if its position changed), lay out the field
1122 again; perhaps we can use an integral mode for it now. */
1123 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
1124 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
1125 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
1126 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
1127 actual_align
= BIGGEST_ALIGNMENT
;
1128 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
1129 actual_align
= (BITS_PER_UNIT
1130 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
1131 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
1133 actual_align
= DECL_OFFSET_ALIGN (field
);
1135 if (known_align
!= actual_align
)
1136 layout_decl (field
, actual_align
);
1138 /* Only the MS bitfields use this. */
1139 if (rli
->prev_field
== NULL
&& DECL_BIT_FIELD_TYPE(field
))
1140 rli
->prev_field
= field
;
1142 /* Now add size of this field to the size of the record. If the size is
1143 not constant, treat the field as being a multiple of bytes and just
1144 adjust the offset, resetting the bit position. Otherwise, apportion the
1145 size amongst the bit position and offset. First handle the case of an
1146 unspecified size, which can happen when we have an invalid nested struct
1147 definition, such as struct j { struct j { int i; } }. The error message
1148 is printed in finish_struct. */
1149 if (DECL_SIZE (field
) == 0)
1151 else if (TREE_CODE (DECL_SIZE_UNIT (field
)) != INTEGER_CST
1152 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field
)))
1155 = size_binop (PLUS_EXPR
, rli
->offset
,
1157 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1158 bitsize_unit_node
)));
1160 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1161 rli
->bitpos
= bitsize_zero_node
;
1162 rli
->offset_align
= MIN (rli
->offset_align
, desired_align
);
1166 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1167 normalize_rli (rli
);
1171 /* Assuming that all the fields have been laid out, this function uses
1172 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1173 indicated by RLI. */
1176 finalize_record_size (record_layout_info rli
)
1178 tree unpadded_size
, unpadded_size_unit
;
1180 /* Now we want just byte and bit offsets, so set the offset alignment
1181 to be a byte and then normalize. */
1182 rli
->offset_align
= BITS_PER_UNIT
;
1183 normalize_rli (rli
);
1185 /* Determine the desired alignment. */
1186 #ifdef ROUND_TYPE_ALIGN
1187 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
1190 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
1193 /* Compute the size so far. Be sure to allow for extra bits in the
1194 size in bytes. We have guaranteed above that it will be no more
1195 than a single byte. */
1196 unpadded_size
= rli_size_so_far (rli
);
1197 unpadded_size_unit
= rli_size_unit_so_far (rli
);
1198 if (! integer_zerop (rli
->bitpos
))
1200 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
1202 /* Round the size up to be a multiple of the required alignment. */
1203 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
1204 TYPE_SIZE_UNIT (rli
->t
) = round_up (unpadded_size_unit
,
1205 TYPE_ALIGN (rli
->t
) / BITS_PER_UNIT
);
1207 if (warn_padded
&& TREE_CONSTANT (unpadded_size
)
1208 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0)
1209 warning ("padding struct size to alignment boundary");
1211 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
1212 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
1213 && TREE_CONSTANT (unpadded_size
))
1217 #ifdef ROUND_TYPE_ALIGN
1219 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1221 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1224 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
1225 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
1227 TYPE_PACKED (rli
->t
) = 0;
1229 if (TYPE_NAME (rli
->t
))
1233 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1234 name
= IDENTIFIER_POINTER (TYPE_NAME (rli
->t
));
1236 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli
->t
)));
1238 if (STRICT_ALIGNMENT
)
1239 warning ("packed attribute causes inefficient alignment for `%s'", name
);
1241 warning ("packed attribute is unnecessary for `%s'", name
);
1245 if (STRICT_ALIGNMENT
)
1246 warning ("packed attribute causes inefficient alignment");
1248 warning ("packed attribute is unnecessary");
1254 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1257 compute_record_mode (tree type
)
1260 enum machine_mode mode
= VOIDmode
;
1262 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1263 However, if possible, we use a mode that fits in a register
1264 instead, in order to allow for better optimization down the
1266 TYPE_MODE (type
) = BLKmode
;
1268 if (! host_integerp (TYPE_SIZE (type
), 1))
1271 /* A record which has any BLKmode members must itself be
1272 BLKmode; it can't go in a register. Unless the member is
1273 BLKmode only because it isn't aligned. */
1274 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1276 if (TREE_CODE (field
) != FIELD_DECL
)
1279 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1280 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1281 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
))
1282 && !(TYPE_SIZE (TREE_TYPE (field
)) != 0
1283 && integer_zerop (TYPE_SIZE (TREE_TYPE (field
)))))
1284 || ! host_integerp (bit_position (field
), 1)
1285 || DECL_SIZE (field
) == 0
1286 || ! host_integerp (DECL_SIZE (field
), 1))
1289 /* If this field is the whole struct, remember its mode so
1290 that, say, we can put a double in a class into a DF
1291 register instead of forcing it to live in the stack. */
1292 if (simple_cst_equal (TYPE_SIZE (type
), DECL_SIZE (field
)))
1293 mode
= DECL_MODE (field
);
1295 #ifdef MEMBER_TYPE_FORCES_BLK
1296 /* With some targets, eg. c4x, it is sub-optimal
1297 to access an aligned BLKmode structure as a scalar. */
1299 if (MEMBER_TYPE_FORCES_BLK (field
, mode
))
1301 #endif /* MEMBER_TYPE_FORCES_BLK */
1304 /* If we only have one real field; use its mode. This only applies to
1305 RECORD_TYPE. This does not apply to unions. */
1306 if (TREE_CODE (type
) == RECORD_TYPE
&& mode
!= VOIDmode
)
1307 TYPE_MODE (type
) = mode
;
1309 TYPE_MODE (type
) = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1311 /* If structure's known alignment is less than what the scalar
1312 mode would need, and it matters, then stick with BLKmode. */
1313 if (TYPE_MODE (type
) != BLKmode
1315 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1316 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1318 /* If this is the only reason this type is BLKmode, then
1319 don't force containing types to be BLKmode. */
1320 TYPE_NO_FORCE_BLK (type
) = 1;
1321 TYPE_MODE (type
) = BLKmode
;
1325 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1329 finalize_type_size (tree type
)
1331 /* Normally, use the alignment corresponding to the mode chosen.
1332 However, where strict alignment is not required, avoid
1333 over-aligning structures, since most compilers do not do this
1336 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1337 && (STRICT_ALIGNMENT
1338 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1339 && TREE_CODE (type
) != QUAL_UNION_TYPE
1340 && TREE_CODE (type
) != ARRAY_TYPE
)))
1342 TYPE_ALIGN (type
) = GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1343 TYPE_USER_ALIGN (type
) = 0;
1346 /* Do machine-dependent extra alignment. */
1347 #ifdef ROUND_TYPE_ALIGN
1349 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1352 /* If we failed to find a simple way to calculate the unit size
1353 of the type, find it by division. */
1354 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1355 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1356 result will fit in sizetype. We will get more efficient code using
1357 sizetype, so we force a conversion. */
1358 TYPE_SIZE_UNIT (type
)
1359 = convert (sizetype
,
1360 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1361 bitsize_unit_node
));
1363 if (TYPE_SIZE (type
) != 0)
1365 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1366 TYPE_SIZE_UNIT (type
)
1367 = round_up (TYPE_SIZE_UNIT (type
), TYPE_ALIGN (type
) / BITS_PER_UNIT
);
1370 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1371 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1372 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1373 if (TYPE_SIZE_UNIT (type
) != 0
1374 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1375 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1377 /* Also layout any other variants of the type. */
1378 if (TYPE_NEXT_VARIANT (type
)
1379 || type
!= TYPE_MAIN_VARIANT (type
))
1382 /* Record layout info of this variant. */
1383 tree size
= TYPE_SIZE (type
);
1384 tree size_unit
= TYPE_SIZE_UNIT (type
);
1385 unsigned int align
= TYPE_ALIGN (type
);
1386 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1387 enum machine_mode mode
= TYPE_MODE (type
);
1389 /* Copy it into all variants. */
1390 for (variant
= TYPE_MAIN_VARIANT (type
);
1392 variant
= TYPE_NEXT_VARIANT (variant
))
1394 TYPE_SIZE (variant
) = size
;
1395 TYPE_SIZE_UNIT (variant
) = size_unit
;
1396 TYPE_ALIGN (variant
) = align
;
1397 TYPE_USER_ALIGN (variant
) = user_align
;
1398 TYPE_MODE (variant
) = mode
;
1403 /* Do all of the work required to layout the type indicated by RLI,
1404 once the fields have been laid out. This function will call `free'
1405 for RLI, unless FREE_P is false. Passing a value other than false
1406 for FREE_P is bad practice; this option only exists to support the
1410 finish_record_layout (record_layout_info rli
, int free_p
)
1412 /* Compute the final size. */
1413 finalize_record_size (rli
);
1415 /* Compute the TYPE_MODE for the record. */
1416 compute_record_mode (rli
->t
);
1418 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1419 finalize_type_size (rli
->t
);
1421 /* Lay out any static members. This is done now because their type
1422 may use the record's type. */
1423 while (rli
->pending_statics
)
1425 layout_decl (TREE_VALUE (rli
->pending_statics
), 0);
1426 rli
->pending_statics
= TREE_CHAIN (rli
->pending_statics
);
1435 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1436 NAME, its fields are chained in reverse on FIELDS.
1438 If ALIGN_TYPE is non-null, it is given the same alignment as
1442 finish_builtin_struct (tree type
, const char *name
, tree fields
,
1447 for (tail
= NULL_TREE
; fields
; tail
= fields
, fields
= next
)
1449 DECL_FIELD_CONTEXT (fields
) = type
;
1450 next
= TREE_CHAIN (fields
);
1451 TREE_CHAIN (fields
) = tail
;
1453 TYPE_FIELDS (type
) = tail
;
1457 TYPE_ALIGN (type
) = TYPE_ALIGN (align_type
);
1458 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (align_type
);
1462 #if 0 /* not yet, should get fixed properly later */
1463 TYPE_NAME (type
) = make_type_decl (get_identifier (name
), type
);
1465 TYPE_NAME (type
) = build_decl (TYPE_DECL
, get_identifier (name
), type
);
1467 TYPE_STUB_DECL (type
) = TYPE_NAME (type
);
1468 layout_decl (TYPE_NAME (type
), 0);
1471 /* Calculate the mode, size, and alignment for TYPE.
1472 For an array type, calculate the element separation as well.
1473 Record TYPE on the chain of permanent or temporary types
1474 so that dbxout will find out about it.
1476 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1477 layout_type does nothing on such a type.
1479 If the type is incomplete, its TYPE_SIZE remains zero. */
1482 layout_type (tree type
)
1487 if (type
== error_mark_node
)
1490 /* Do nothing if type has been laid out before. */
1491 if (TYPE_SIZE (type
))
1494 switch (TREE_CODE (type
))
1497 /* This kind of type is the responsibility
1498 of the language-specific code. */
1501 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1502 if (TYPE_PRECISION (type
) == 0)
1503 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1505 /* ... fall through ... */
1510 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1511 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1512 TYPE_UNSIGNED (type
) = 1;
1514 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
1516 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1517 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1521 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
1522 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1523 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1527 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1529 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1530 (TREE_CODE (TREE_TYPE (type
)) == REAL_TYPE
1531 ? MODE_COMPLEX_FLOAT
: MODE_COMPLEX_INT
),
1533 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1534 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1539 int nunits
= TYPE_VECTOR_SUBPARTS (type
);
1540 tree nunits_tree
= build_int_cst (NULL_TREE
, nunits
, 0);
1541 tree innertype
= TREE_TYPE (type
);
1543 if (nunits
& (nunits
- 1))
1546 /* Find an appropriate mode for the vector type. */
1547 if (TYPE_MODE (type
) == VOIDmode
)
1549 enum machine_mode innermode
= TYPE_MODE (innertype
);
1550 enum machine_mode mode
;
1552 /* First, look for a supported vector type. */
1553 if (GET_MODE_CLASS (innermode
) == MODE_FLOAT
)
1554 mode
= MIN_MODE_VECTOR_FLOAT
;
1556 mode
= MIN_MODE_VECTOR_INT
;
1558 for (; mode
!= VOIDmode
; mode
= GET_MODE_WIDER_MODE (mode
))
1559 if (GET_MODE_NUNITS (mode
) == nunits
1560 && GET_MODE_INNER (mode
) == innermode
1561 && VECTOR_MODE_SUPPORTED_P (mode
))
1564 /* For integers, try mapping it to a same-sized scalar mode. */
1565 if (mode
== VOIDmode
1566 && GET_MODE_CLASS (innermode
) == MODE_INT
)
1567 mode
= mode_for_size (nunits
* GET_MODE_BITSIZE (innermode
),
1570 if (mode
== VOIDmode
|| !have_regs_of_mode
[mode
])
1571 TYPE_MODE (type
) = BLKmode
;
1573 TYPE_MODE (type
) = mode
;
1576 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1577 TYPE_SIZE_UNIT (type
) = int_const_binop (MULT_EXPR
,
1578 TYPE_SIZE_UNIT (innertype
),
1580 TYPE_SIZE (type
) = int_const_binop (MULT_EXPR
, TYPE_SIZE (innertype
),
1586 /* This is an incomplete type and so doesn't have a size. */
1587 TYPE_ALIGN (type
) = 1;
1588 TYPE_USER_ALIGN (type
) = 0;
1589 TYPE_MODE (type
) = VOIDmode
;
1593 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1594 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1595 /* A pointer might be MODE_PARTIAL_INT,
1596 but ptrdiff_t must be integral. */
1597 TYPE_MODE (type
) = mode_for_size (POINTER_SIZE
, MODE_INT
, 0);
1602 /* It's hard to see what the mode and size of a function ought to
1603 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1604 make it consistent with that. */
1605 TYPE_MODE (type
) = mode_for_size (FUNCTION_BOUNDARY
, MODE_INT
, 0);
1606 TYPE_SIZE (type
) = bitsize_int (FUNCTION_BOUNDARY
);
1607 TYPE_SIZE_UNIT (type
) = size_int (FUNCTION_BOUNDARY
/ BITS_PER_UNIT
);
1611 case REFERENCE_TYPE
:
1614 enum machine_mode mode
= ((TREE_CODE (type
) == REFERENCE_TYPE
1615 && reference_types_internal
)
1616 ? Pmode
: TYPE_MODE (type
));
1618 int nbits
= GET_MODE_BITSIZE (mode
);
1620 TYPE_SIZE (type
) = bitsize_int (nbits
);
1621 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (mode
));
1622 TYPE_UNSIGNED (type
) = 1;
1623 TYPE_PRECISION (type
) = nbits
;
1629 tree index
= TYPE_DOMAIN (type
);
1630 tree element
= TREE_TYPE (type
);
1632 build_pointer_type (element
);
1634 /* We need to know both bounds in order to compute the size. */
1635 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1636 && TYPE_SIZE (element
))
1638 tree ub
= TYPE_MAX_VALUE (index
);
1639 tree lb
= TYPE_MIN_VALUE (index
);
1643 /* The initial subtraction should happen in the original type so
1644 that (possible) negative values are handled appropriately. */
1645 length
= size_binop (PLUS_EXPR
, size_one_node
,
1647 fold (build2 (MINUS_EXPR
,
1651 /* Special handling for arrays of bits (for Chill). */
1652 element_size
= TYPE_SIZE (element
);
1653 if (TYPE_PACKED (type
) && INTEGRAL_TYPE_P (element
)
1654 && (integer_zerop (TYPE_MAX_VALUE (element
))
1655 || integer_onep (TYPE_MAX_VALUE (element
)))
1656 && host_integerp (TYPE_MIN_VALUE (element
), 1))
1658 HOST_WIDE_INT maxvalue
1659 = tree_low_cst (TYPE_MAX_VALUE (element
), 1);
1660 HOST_WIDE_INT minvalue
1661 = tree_low_cst (TYPE_MIN_VALUE (element
), 1);
1663 if (maxvalue
- minvalue
== 1
1664 && (maxvalue
== 1 || maxvalue
== 0))
1665 element_size
= integer_one_node
;
1668 /* If neither bound is a constant and sizetype is signed, make
1669 sure the size is never negative. We should really do this
1670 if *either* bound is non-constant, but this is the best
1671 compromise between C and Ada. */
1672 if (!TYPE_UNSIGNED (sizetype
)
1673 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
1674 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
1675 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
1677 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1678 convert (bitsizetype
, length
));
1680 /* If we know the size of the element, calculate the total
1681 size directly, rather than do some division thing below.
1682 This optimization helps Fortran assumed-size arrays
1683 (where the size of the array is determined at runtime)
1685 Note that we can't do this in the case where the size of
1686 the elements is one bit since TYPE_SIZE_UNIT cannot be
1687 set correctly in that case. */
1688 if (TYPE_SIZE_UNIT (element
) != 0 && ! integer_onep (element_size
))
1689 TYPE_SIZE_UNIT (type
)
1690 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1693 /* Now round the alignment and size,
1694 using machine-dependent criteria if any. */
1696 #ifdef ROUND_TYPE_ALIGN
1698 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1700 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1702 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (element
);
1703 TYPE_MODE (type
) = BLKmode
;
1704 if (TYPE_SIZE (type
) != 0
1705 #ifdef MEMBER_TYPE_FORCES_BLK
1706 && ! MEMBER_TYPE_FORCES_BLK (type
, VOIDmode
)
1708 /* BLKmode elements force BLKmode aggregate;
1709 else extract/store fields may lose. */
1710 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
1711 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
1713 /* One-element arrays get the component type's mode. */
1714 if (simple_cst_equal (TYPE_SIZE (type
),
1715 TYPE_SIZE (TREE_TYPE (type
))))
1716 TYPE_MODE (type
) = TYPE_MODE (TREE_TYPE (type
));
1719 = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1721 if (TYPE_MODE (type
) != BLKmode
1722 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
1723 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
))
1724 && TYPE_MODE (type
) != BLKmode
)
1726 TYPE_NO_FORCE_BLK (type
) = 1;
1727 TYPE_MODE (type
) = BLKmode
;
1735 case QUAL_UNION_TYPE
:
1738 record_layout_info rli
;
1740 /* Initialize the layout information. */
1741 rli
= start_record_layout (type
);
1743 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1744 in the reverse order in building the COND_EXPR that denotes
1745 its size. We reverse them again later. */
1746 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1747 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1749 /* Place all the fields. */
1750 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1751 place_field (rli
, field
);
1753 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1754 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1756 if (lang_adjust_rli
)
1757 (*lang_adjust_rli
) (rli
);
1759 /* Finish laying out the record. */
1760 finish_record_layout (rli
, /*free_p=*/true);
1764 case SET_TYPE
: /* Used by Chill and Pascal. */
1765 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
1766 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
)
1770 #ifndef SET_WORD_SIZE
1771 #define SET_WORD_SIZE BITS_PER_WORD
1773 unsigned int alignment
1774 = set_alignment
? set_alignment
: SET_WORD_SIZE
;
1775 HOST_WIDE_INT size_in_bits
1776 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type
)), 0)
1777 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type
)), 0) + 1);
1778 HOST_WIDE_INT rounded_size
1779 = ((size_in_bits
+ alignment
- 1) / alignment
) * alignment
;
1781 if (rounded_size
> (int) alignment
)
1782 TYPE_MODE (type
) = BLKmode
;
1784 TYPE_MODE (type
) = mode_for_size (alignment
, MODE_INT
, 1);
1786 TYPE_SIZE (type
) = bitsize_int (rounded_size
);
1787 TYPE_SIZE_UNIT (type
) = size_int (rounded_size
/ BITS_PER_UNIT
);
1788 TYPE_ALIGN (type
) = alignment
;
1789 TYPE_USER_ALIGN (type
) = 0;
1790 TYPE_PRECISION (type
) = size_in_bits
;
1795 /* The size may vary in different languages, so the language front end
1796 should fill in the size. */
1797 TYPE_ALIGN (type
) = BIGGEST_ALIGNMENT
;
1798 TYPE_USER_ALIGN (type
) = 0;
1799 TYPE_MODE (type
) = BLKmode
;
1806 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1807 records and unions, finish_record_layout already called this
1809 if (TREE_CODE (type
) != RECORD_TYPE
1810 && TREE_CODE (type
) != UNION_TYPE
1811 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
1812 finalize_type_size (type
);
1814 /* If this type is created before sizetype has been permanently set,
1815 record it so set_sizetype can fix it up. */
1817 early_type_list
= tree_cons (NULL_TREE
, type
, early_type_list
);
1819 /* If an alias set has been set for this aggregate when it was incomplete,
1820 force it into alias set 0.
1821 This is too conservative, but we cannot call record_component_aliases
1822 here because some frontends still change the aggregates after
1824 if (AGGREGATE_TYPE_P (type
) && TYPE_ALIAS_SET_KNOWN_P (type
))
1825 TYPE_ALIAS_SET (type
) = 0;
1828 /* Create and return a type for signed integers of PRECISION bits. */
1831 make_signed_type (int precision
)
1833 tree type
= make_node (INTEGER_TYPE
);
1835 TYPE_PRECISION (type
) = precision
;
1837 fixup_signed_type (type
);
1841 /* Create and return a type for unsigned integers of PRECISION bits. */
1844 make_unsigned_type (int precision
)
1846 tree type
= make_node (INTEGER_TYPE
);
1848 TYPE_PRECISION (type
) = precision
;
1850 fixup_unsigned_type (type
);
1854 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1855 value to enable integer types to be created. */
1858 initialize_sizetypes (void)
1860 tree t
= make_node (INTEGER_TYPE
);
1862 TYPE_MODE (t
) = SImode
;
1863 TYPE_ALIGN (t
) = GET_MODE_ALIGNMENT (SImode
);
1864 TYPE_USER_ALIGN (t
) = 0;
1865 TYPE_SIZE (t
) = build_int_cst (t
, GET_MODE_BITSIZE (SImode
), 0);
1866 TYPE_SIZE_UNIT (t
) = build_int_cst (t
, GET_MODE_SIZE (SImode
), 0);
1867 TYPE_UNSIGNED (t
) = 1;
1868 TYPE_PRECISION (t
) = GET_MODE_BITSIZE (SImode
);
1869 TYPE_MIN_VALUE (t
) = build_int_cst (t
, 0, 0);
1870 TYPE_IS_SIZETYPE (t
) = 1;
1872 /* 1000 avoids problems with possible overflow and is certainly
1873 larger than any size value we'd want to be storing. */
1874 TYPE_MAX_VALUE (t
) = build_int_cst (t
, 1000, 0);
1876 /* These two must be different nodes because of the caching done in
1879 bitsizetype
= copy_node (t
);
1882 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1883 Also update the type of any standard type's sizes made so far. */
1886 set_sizetype (tree type
)
1888 int oprecision
= TYPE_PRECISION (type
);
1889 /* The *bitsizetype types use a precision that avoids overflows when
1890 calculating signed sizes / offsets in bits. However, when
1891 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1893 int precision
= MIN (oprecision
+ BITS_PER_UNIT_LOG
+ 1,
1894 2 * HOST_BITS_PER_WIDE_INT
);
1901 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1902 sizetype
= copy_node (type
);
1903 TYPE_ORIG_SIZE_TYPE (sizetype
) = type
;
1904 TYPE_IS_SIZETYPE (sizetype
) = 1;
1905 bitsizetype
= make_node (INTEGER_TYPE
);
1906 TYPE_NAME (bitsizetype
) = TYPE_NAME (type
);
1907 TYPE_PRECISION (bitsizetype
) = precision
;
1908 TYPE_IS_SIZETYPE (bitsizetype
) = 1;
1910 if (TYPE_UNSIGNED (type
))
1911 fixup_unsigned_type (bitsizetype
);
1913 fixup_signed_type (bitsizetype
);
1915 layout_type (bitsizetype
);
1917 if (TYPE_UNSIGNED (type
))
1919 usizetype
= sizetype
;
1920 ubitsizetype
= bitsizetype
;
1921 ssizetype
= copy_node (make_signed_type (oprecision
));
1922 sbitsizetype
= copy_node (make_signed_type (precision
));
1926 ssizetype
= sizetype
;
1927 sbitsizetype
= bitsizetype
;
1928 usizetype
= copy_node (make_unsigned_type (oprecision
));
1929 ubitsizetype
= copy_node (make_unsigned_type (precision
));
1932 TYPE_NAME (bitsizetype
) = get_identifier ("bit_size_type");
1934 /* Show is a sizetype, is a main type, and has no pointers to it. */
1935 for (i
= 0; i
< ARRAY_SIZE (sizetype_tab
); i
++)
1937 TYPE_IS_SIZETYPE (sizetype_tab
[i
]) = 1;
1938 TYPE_MAIN_VARIANT (sizetype_tab
[i
]) = sizetype_tab
[i
];
1939 TYPE_NEXT_VARIANT (sizetype_tab
[i
]) = 0;
1940 TYPE_POINTER_TO (sizetype_tab
[i
]) = 0;
1941 TYPE_REFERENCE_TO (sizetype_tab
[i
]) = 0;
1944 /* Go down each of the types we already made and set the proper type
1945 for the sizes in them. */
1946 for (t
= early_type_list
; t
!= 0; t
= TREE_CHAIN (t
))
1948 if (TREE_CODE (TREE_VALUE (t
)) != INTEGER_TYPE
1949 && TREE_CODE (TREE_VALUE (t
)) != BOOLEAN_TYPE
)
1952 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t
))) = bitsizetype
;
1953 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t
))) = sizetype
;
1956 early_type_list
= 0;
1960 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1961 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1962 for TYPE, based on the PRECISION and whether or not the TYPE
1963 IS_UNSIGNED. PRECISION need not correspond to a width supported
1964 natively by the hardware; for example, on a machine with 8-bit,
1965 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1969 set_min_and_max_values_for_integral_type (tree type
,
1978 min_value
= build_int_cst (type
, 0, 0);
1980 = build_int_cst (type
, precision
- HOST_BITS_PER_WIDE_INT
>= 0
1981 ? -1 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
1982 precision
- HOST_BITS_PER_WIDE_INT
> 0
1983 ? ((unsigned HOST_WIDE_INT
) ~0
1984 >> (HOST_BITS_PER_WIDE_INT
1985 - (precision
- HOST_BITS_PER_WIDE_INT
)))
1991 = build_int_cst (type
,
1992 (precision
- HOST_BITS_PER_WIDE_INT
> 0
1993 ? 0 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
1994 (((HOST_WIDE_INT
) (-1)
1995 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1996 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
1999 = build_int_cst (type
,
2000 (precision
- HOST_BITS_PER_WIDE_INT
> 0
2001 ? -1 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
2002 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
2003 ? (((HOST_WIDE_INT
) 1
2004 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
2008 TYPE_MIN_VALUE (type
) = min_value
;
2009 TYPE_MAX_VALUE (type
) = max_value
;
2012 /* Set the extreme values of TYPE based on its precision in bits,
2013 then lay it out. Used when make_signed_type won't do
2014 because the tree code is not INTEGER_TYPE.
2015 E.g. for Pascal, when the -fsigned-char option is given. */
2018 fixup_signed_type (tree type
)
2020 int precision
= TYPE_PRECISION (type
);
2022 /* We can not represent properly constants greater then
2023 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2024 as they are used by i386 vector extensions and friends. */
2025 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2026 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2028 set_min_and_max_values_for_integral_type (type
, precision
,
2029 /*is_unsigned=*/false);
2031 /* Lay out the type: set its alignment, size, etc. */
2035 /* Set the extreme values of TYPE based on its precision in bits,
2036 then lay it out. This is used both in `make_unsigned_type'
2037 and for enumeral types. */
2040 fixup_unsigned_type (tree type
)
2042 int precision
= TYPE_PRECISION (type
);
2044 /* We can not represent properly constants greater then
2045 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2046 as they are used by i386 vector extensions and friends. */
2047 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2048 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2050 set_min_and_max_values_for_integral_type (type
, precision
,
2051 /*is_unsigned=*/true);
2053 /* Lay out the type: set its alignment, size, etc. */
2057 /* Find the best machine mode to use when referencing a bit field of length
2058 BITSIZE bits starting at BITPOS.
2060 The underlying object is known to be aligned to a boundary of ALIGN bits.
2061 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2062 larger than LARGEST_MODE (usually SImode).
2064 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2065 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2066 mode meeting these conditions.
2068 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2069 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2070 all the conditions. */
2073 get_best_mode (int bitsize
, int bitpos
, unsigned int align
,
2074 enum machine_mode largest_mode
, int volatilep
)
2076 enum machine_mode mode
;
2077 unsigned int unit
= 0;
2079 /* Find the narrowest integer mode that contains the bit field. */
2080 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
2081 mode
= GET_MODE_WIDER_MODE (mode
))
2083 unit
= GET_MODE_BITSIZE (mode
);
2084 if ((bitpos
% unit
) + bitsize
<= unit
)
2088 if (mode
== VOIDmode
2089 /* It is tempting to omit the following line
2090 if STRICT_ALIGNMENT is true.
2091 But that is incorrect, since if the bitfield uses part of 3 bytes
2092 and we use a 4-byte mode, we could get a spurious segv
2093 if the extra 4th byte is past the end of memory.
2094 (Though at least one Unix compiler ignores this problem:
2095 that on the Sequent 386 machine. */
2096 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
2097 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
2100 if (SLOW_BYTE_ACCESS
&& ! volatilep
)
2102 enum machine_mode wide_mode
= VOIDmode
, tmode
;
2104 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
2105 tmode
= GET_MODE_WIDER_MODE (tmode
))
2107 unit
= GET_MODE_BITSIZE (tmode
);
2108 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
2109 && unit
<= BITS_PER_WORD
2110 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
2111 && (largest_mode
== VOIDmode
2112 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
2116 if (wide_mode
!= VOIDmode
)
2123 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2124 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2127 get_mode_bounds (enum machine_mode mode
, int sign
,
2128 enum machine_mode target_mode
,
2129 rtx
*mmin
, rtx
*mmax
)
2131 unsigned size
= GET_MODE_BITSIZE (mode
);
2132 unsigned HOST_WIDE_INT min_val
, max_val
;
2134 if (size
> HOST_BITS_PER_WIDE_INT
)
2139 min_val
= -((unsigned HOST_WIDE_INT
) 1 << (size
- 1));
2140 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1)) - 1;
2145 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1) << 1) - 1;
2148 *mmin
= GEN_INT (trunc_int_for_mode (min_val
, target_mode
));
2149 *mmax
= GEN_INT (trunc_int_for_mode (max_val
, target_mode
));
2152 #include "gt-stor-layout.h"