1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1996, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
36 #include "langhooks.h"
40 /* Data type for the expressions representing sizes of data types.
41 It is the first integer type laid out. */
42 tree sizetype_tab
[(int) TYPE_KIND_LAST
];
44 /* If nonzero, this is an upper limit on alignment of structure fields.
45 The value is measured in bits. */
46 unsigned int maximum_field_alignment
= TARGET_DEFAULT_PACK_STRUCT
* BITS_PER_UNIT
;
47 /* ... and its original value in bytes, specified via -fpack-struct=<value>. */
48 unsigned int initial_max_fld_align
= TARGET_DEFAULT_PACK_STRUCT
;
50 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
51 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
52 called only by a front end. */
53 static int reference_types_internal
= 0;
55 static void finalize_record_size (record_layout_info
);
56 static void finalize_type_size (tree
);
57 static void place_union_field (record_layout_info
, tree
);
58 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
59 static int excess_unit_span (HOST_WIDE_INT
, HOST_WIDE_INT
, HOST_WIDE_INT
,
62 extern void debug_rli (record_layout_info
);
64 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
66 static GTY(()) tree pending_sizes
;
68 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
72 internal_reference_types (void)
74 reference_types_internal
= 1;
77 /* Get a list of all the objects put on the pending sizes list. */
80 get_pending_sizes (void)
82 tree chain
= pending_sizes
;
88 /* Add EXPR to the pending sizes list. */
91 put_pending_size (tree expr
)
93 /* Strip any simple arithmetic from EXPR to see if it has an underlying
95 expr
= skip_simple_arithmetic (expr
);
97 if (TREE_CODE (expr
) == SAVE_EXPR
)
98 pending_sizes
= tree_cons (NULL_TREE
, expr
, pending_sizes
);
101 /* Put a chain of objects into the pending sizes list, which must be
105 put_pending_sizes (tree chain
)
107 gcc_assert (!pending_sizes
);
108 pending_sizes
= chain
;
111 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
112 to serve as the actual size-expression for a type or decl. */
115 variable_size (tree size
)
119 /* If the language-processor is to take responsibility for variable-sized
120 items (e.g., languages which have elaboration procedures like Ada),
121 just return SIZE unchanged. Likewise for self-referential sizes and
123 if (TREE_CONSTANT (size
)
124 || lang_hooks
.decls
.global_bindings_p () < 0
125 || CONTAINS_PLACEHOLDER_P (size
))
128 size
= save_expr (size
);
130 /* If an array with a variable number of elements is declared, and
131 the elements require destruction, we will emit a cleanup for the
132 array. That cleanup is run both on normal exit from the block
133 and in the exception-handler for the block. Normally, when code
134 is used in both ordinary code and in an exception handler it is
135 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
136 not wish to do that here; the array-size is the same in both
138 save
= skip_simple_arithmetic (size
);
140 if (cfun
&& cfun
->x_dont_save_pending_sizes_p
)
141 /* The front-end doesn't want us to keep a list of the expressions
142 that determine sizes for variable size objects. Trust it. */
145 if (lang_hooks
.decls
.global_bindings_p ())
147 if (TREE_CONSTANT (size
))
148 error ("type size can%'t be explicitly evaluated");
150 error ("variable-size type declared outside of any function");
152 return size_one_node
;
155 put_pending_size (save
);
160 #ifndef MAX_FIXED_MODE_SIZE
161 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
164 /* Return the machine mode to use for a nonscalar of SIZE bits. The
165 mode must be in class CLASS, and have exactly that many value bits;
166 it may have padding as well. If LIMIT is nonzero, modes of wider
167 than MAX_FIXED_MODE_SIZE will not be used. */
170 mode_for_size (unsigned int size
, enum mode_class
class, int limit
)
172 enum machine_mode mode
;
174 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
177 /* Get the first mode which has this size, in the specified class. */
178 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
179 mode
= GET_MODE_WIDER_MODE (mode
))
180 if (GET_MODE_PRECISION (mode
) == size
)
186 /* Similar, except passed a tree node. */
189 mode_for_size_tree (tree size
, enum mode_class
class, int limit
)
191 if (TREE_CODE (size
) != INTEGER_CST
192 || TREE_OVERFLOW (size
)
193 /* What we really want to say here is that the size can fit in a
194 host integer, but we know there's no way we'd find a mode for
195 this many bits, so there's no point in doing the precise test. */
196 || compare_tree_int (size
, 1000) > 0)
199 return mode_for_size (tree_low_cst (size
, 1), class, limit
);
202 /* Similar, but never return BLKmode; return the narrowest mode that
203 contains at least the requested number of value bits. */
206 smallest_mode_for_size (unsigned int size
, enum mode_class
class)
208 enum machine_mode mode
;
210 /* Get the first mode which has at least this size, in the
212 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
213 mode
= GET_MODE_WIDER_MODE (mode
))
214 if (GET_MODE_PRECISION (mode
) >= size
)
220 /* Find an integer mode of the exact same size, or BLKmode on failure. */
223 int_mode_for_mode (enum machine_mode mode
)
225 switch (GET_MODE_CLASS (mode
))
228 case MODE_PARTIAL_INT
:
231 case MODE_COMPLEX_INT
:
232 case MODE_COMPLEX_FLOAT
:
234 case MODE_VECTOR_INT
:
235 case MODE_VECTOR_FLOAT
:
236 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
243 /* ... fall through ... */
253 /* Return the alignment of MODE. This will be bounded by 1 and
254 BIGGEST_ALIGNMENT. */
257 get_mode_alignment (enum machine_mode mode
)
259 return MIN (BIGGEST_ALIGNMENT
, MAX (1, mode_base_align
[mode
]*BITS_PER_UNIT
));
263 /* Subroutine of layout_decl: Force alignment required for the data type.
264 But if the decl itself wants greater alignment, don't override that. */
267 do_type_align (tree type
, tree decl
)
269 if (TYPE_ALIGN (type
) > DECL_ALIGN (decl
))
271 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
272 if (TREE_CODE (decl
) == FIELD_DECL
)
273 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
277 /* Set the size, mode and alignment of a ..._DECL node.
278 TYPE_DECL does need this for C++.
279 Note that LABEL_DECL and CONST_DECL nodes do not need this,
280 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
281 Don't call layout_decl for them.
283 KNOWN_ALIGN is the amount of alignment we can assume this
284 decl has with no special effort. It is relevant only for FIELD_DECLs
285 and depends on the previous fields.
286 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
287 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
288 the record will be aligned to suit. */
291 layout_decl (tree decl
, unsigned int known_align
)
293 tree type
= TREE_TYPE (decl
);
294 enum tree_code code
= TREE_CODE (decl
);
297 if (code
== CONST_DECL
)
300 gcc_assert (code
== VAR_DECL
|| code
== PARM_DECL
|| code
== RESULT_DECL
301 || code
== TYPE_DECL
||code
== FIELD_DECL
);
303 rtl
= DECL_RTL_IF_SET (decl
);
305 if (type
== error_mark_node
)
306 type
= void_type_node
;
308 /* Usually the size and mode come from the data type without change,
309 however, the front-end may set the explicit width of the field, so its
310 size may not be the same as the size of its type. This happens with
311 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
312 also happens with other fields. For example, the C++ front-end creates
313 zero-sized fields corresponding to empty base classes, and depends on
314 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
315 size in bytes from the size in bits. If we have already set the mode,
316 don't set it again since we can be called twice for FIELD_DECLs. */
318 DECL_UNSIGNED (decl
) = TYPE_UNSIGNED (type
);
319 if (DECL_MODE (decl
) == VOIDmode
)
320 DECL_MODE (decl
) = TYPE_MODE (type
);
322 if (DECL_SIZE (decl
) == 0)
324 DECL_SIZE (decl
) = TYPE_SIZE (type
);
325 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
327 else if (DECL_SIZE_UNIT (decl
) == 0)
328 DECL_SIZE_UNIT (decl
)
329 = fold_convert (sizetype
, size_binop (CEIL_DIV_EXPR
, DECL_SIZE (decl
),
332 if (code
!= FIELD_DECL
)
333 /* For non-fields, update the alignment from the type. */
334 do_type_align (type
, decl
);
336 /* For fields, it's a bit more complicated... */
338 bool old_user_align
= DECL_USER_ALIGN (decl
);
340 if (DECL_BIT_FIELD (decl
))
342 DECL_BIT_FIELD_TYPE (decl
) = type
;
344 /* A zero-length bit-field affects the alignment of the next
346 if (integer_zerop (DECL_SIZE (decl
))
347 && ! DECL_PACKED (decl
)
348 && ! targetm
.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl
)))
350 #ifdef PCC_BITFIELD_TYPE_MATTERS
351 if (PCC_BITFIELD_TYPE_MATTERS
)
352 do_type_align (type
, decl
);
356 #ifdef EMPTY_FIELD_BOUNDARY
357 if (EMPTY_FIELD_BOUNDARY
> DECL_ALIGN (decl
))
359 DECL_ALIGN (decl
) = EMPTY_FIELD_BOUNDARY
;
360 DECL_USER_ALIGN (decl
) = 0;
366 /* See if we can use an ordinary integer mode for a bit-field.
367 Conditions are: a fixed size that is correct for another mode
368 and occupying a complete byte or bytes on proper boundary. */
369 if (TYPE_SIZE (type
) != 0
370 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
371 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
)
373 enum machine_mode xmode
374 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
378 || known_align
>= GET_MODE_ALIGNMENT (xmode
)))
380 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
382 DECL_MODE (decl
) = xmode
;
383 DECL_BIT_FIELD (decl
) = 0;
387 /* Turn off DECL_BIT_FIELD if we won't need it set. */
388 if (TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
389 && known_align
>= TYPE_ALIGN (type
)
390 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
))
391 DECL_BIT_FIELD (decl
) = 0;
393 else if (DECL_PACKED (decl
) && DECL_USER_ALIGN (decl
))
394 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
395 round up; we'll reduce it again below. We want packing to
396 supersede USER_ALIGN inherited from the type, but defer to
397 alignment explicitly specified on the field decl. */;
399 do_type_align (type
, decl
);
401 /* If the field is of variable size, we can't misalign it since we
402 have no way to make a temporary to align the result. But this
403 isn't an issue if the decl is not addressable. Likewise if it
406 Note that do_type_align may set DECL_USER_ALIGN, so we need to
407 check old_user_align instead. */
408 if (DECL_PACKED (decl
)
410 && (DECL_NONADDRESSABLE_P (decl
)
411 || DECL_SIZE_UNIT (decl
) == 0
412 || TREE_CODE (DECL_SIZE_UNIT (decl
)) == INTEGER_CST
))
413 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
415 if (! DECL_USER_ALIGN (decl
) && ! DECL_PACKED (decl
))
417 /* Some targets (i.e. i386, VMS) limit struct field alignment
418 to a lower boundary than alignment of variables unless
419 it was overridden by attribute aligned. */
420 #ifdef BIGGEST_FIELD_ALIGNMENT
422 = MIN (DECL_ALIGN (decl
), (unsigned) BIGGEST_FIELD_ALIGNMENT
);
424 #ifdef ADJUST_FIELD_ALIGN
425 DECL_ALIGN (decl
) = ADJUST_FIELD_ALIGN (decl
, DECL_ALIGN (decl
));
429 /* Should this be controlled by DECL_USER_ALIGN, too? */
430 if (maximum_field_alignment
!= 0)
431 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), maximum_field_alignment
);
434 /* Evaluate nonconstant size only once, either now or as soon as safe. */
435 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
436 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
437 if (DECL_SIZE_UNIT (decl
) != 0
438 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
439 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
441 /* If requested, warn about definitions of large data objects. */
443 && (code
== VAR_DECL
|| code
== PARM_DECL
)
444 && ! DECL_EXTERNAL (decl
))
446 tree size
= DECL_SIZE_UNIT (decl
);
448 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
449 && compare_tree_int (size
, larger_than_size
) > 0)
451 int size_as_int
= TREE_INT_CST_LOW (size
);
453 if (compare_tree_int (size
, size_as_int
) == 0)
454 warning ("%Jsize of %qD is %d bytes", decl
, decl
, size_as_int
);
456 warning ("%Jsize of %qD is larger than %d bytes",
457 decl
, decl
, larger_than_size
);
461 /* If the RTL was already set, update its mode and mem attributes. */
464 PUT_MODE (rtl
, DECL_MODE (decl
));
465 SET_DECL_RTL (decl
, 0);
466 set_mem_attributes (rtl
, decl
, 1);
467 SET_DECL_RTL (decl
, rtl
);
471 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
472 a previous call to layout_decl and calls it again. */
475 relayout_decl (tree decl
)
477 DECL_SIZE (decl
) = DECL_SIZE_UNIT (decl
) = 0;
478 DECL_MODE (decl
) = VOIDmode
;
479 DECL_ALIGN (decl
) = 0;
480 SET_DECL_RTL (decl
, 0);
482 layout_decl (decl
, 0);
485 /* Hook for a front-end function that can modify the record layout as needed
486 immediately before it is finalized. */
488 void (*lang_adjust_rli
) (record_layout_info
) = 0;
491 set_lang_adjust_rli (void (*f
) (record_layout_info
))
496 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
497 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
498 is to be passed to all other layout functions for this record. It is the
499 responsibility of the caller to call `free' for the storage returned.
500 Note that garbage collection is not permitted until we finish laying
504 start_record_layout (tree t
)
506 record_layout_info rli
= xmalloc (sizeof (struct record_layout_info_s
));
510 /* If the type has a minimum specified alignment (via an attribute
511 declaration, for example) use it -- otherwise, start with a
512 one-byte alignment. */
513 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
514 rli
->unpacked_align
= rli
->record_align
;
515 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
517 #ifdef STRUCTURE_SIZE_BOUNDARY
518 /* Packed structures don't need to have minimum size. */
519 if (! TYPE_PACKED (t
))
520 rli
->record_align
= MAX (rli
->record_align
, (unsigned) STRUCTURE_SIZE_BOUNDARY
);
523 rli
->offset
= size_zero_node
;
524 rli
->bitpos
= bitsize_zero_node
;
526 rli
->pending_statics
= 0;
527 rli
->packed_maybe_necessary
= 0;
532 /* These four routines perform computations that convert between
533 the offset/bitpos forms and byte and bit offsets. */
536 bit_from_pos (tree offset
, tree bitpos
)
538 return size_binop (PLUS_EXPR
, bitpos
,
539 size_binop (MULT_EXPR
,
540 fold_convert (bitsizetype
, offset
),
545 byte_from_pos (tree offset
, tree bitpos
)
547 return size_binop (PLUS_EXPR
, offset
,
548 fold_convert (sizetype
,
549 size_binop (TRUNC_DIV_EXPR
, bitpos
,
550 bitsize_unit_node
)));
554 pos_from_bit (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
,
557 *poffset
= size_binop (MULT_EXPR
,
558 fold_convert (sizetype
,
559 size_binop (FLOOR_DIV_EXPR
, pos
,
560 bitsize_int (off_align
))),
561 size_int (off_align
/ BITS_PER_UNIT
));
562 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
565 /* Given a pointer to bit and byte offsets and an offset alignment,
566 normalize the offsets so they are within the alignment. */
569 normalize_offset (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
)
571 /* If the bit position is now larger than it should be, adjust it
573 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
575 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
576 bitsize_int (off_align
));
579 = size_binop (PLUS_EXPR
, *poffset
,
580 size_binop (MULT_EXPR
,
581 fold_convert (sizetype
, extra_aligns
),
582 size_int (off_align
/ BITS_PER_UNIT
)));
585 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
589 /* Print debugging information about the information in RLI. */
592 debug_rli (record_layout_info rli
)
594 print_node_brief (stderr
, "type", rli
->t
, 0);
595 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
596 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
598 fprintf (stderr
, "\naligns: rec = %u, unpack = %u, off = %u\n",
599 rli
->record_align
, rli
->unpacked_align
,
601 if (rli
->packed_maybe_necessary
)
602 fprintf (stderr
, "packed may be necessary\n");
604 if (rli
->pending_statics
)
606 fprintf (stderr
, "pending statics:\n");
607 debug_tree (rli
->pending_statics
);
611 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
612 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
615 normalize_rli (record_layout_info rli
)
617 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
620 /* Returns the size in bytes allocated so far. */
623 rli_size_unit_so_far (record_layout_info rli
)
625 return byte_from_pos (rli
->offset
, rli
->bitpos
);
628 /* Returns the size in bits allocated so far. */
631 rli_size_so_far (record_layout_info rli
)
633 return bit_from_pos (rli
->offset
, rli
->bitpos
);
636 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
637 the next available location is given by KNOWN_ALIGN. Update the
638 variable alignment fields in RLI, and return the alignment to give
642 update_alignment_for_field (record_layout_info rli
, tree field
,
643 unsigned int known_align
)
645 /* The alignment required for FIELD. */
646 unsigned int desired_align
;
647 /* The type of this field. */
648 tree type
= TREE_TYPE (field
);
649 /* True if the field was explicitly aligned by the user. */
653 /* Lay out the field so we know what alignment it needs. */
654 layout_decl (field
, known_align
);
655 desired_align
= DECL_ALIGN (field
);
656 user_align
= DECL_USER_ALIGN (field
);
658 is_bitfield
= (type
!= error_mark_node
659 && DECL_BIT_FIELD_TYPE (field
)
660 && ! integer_zerop (TYPE_SIZE (type
)));
662 /* Record must have at least as much alignment as any field.
663 Otherwise, the alignment of the field within the record is
665 if (is_bitfield
&& targetm
.ms_bitfield_layout_p (rli
->t
))
667 /* Here, the alignment of the underlying type of a bitfield can
668 affect the alignment of a record; even a zero-sized field
669 can do this. The alignment should be to the alignment of
670 the type, except that for zero-size bitfields this only
671 applies if there was an immediately prior, nonzero-size
672 bitfield. (That's the way it is, experimentally.) */
673 if (! integer_zerop (DECL_SIZE (field
))
674 ? ! DECL_PACKED (field
)
676 && DECL_BIT_FIELD_TYPE (rli
->prev_field
)
677 && ! integer_zerop (DECL_SIZE (rli
->prev_field
))))
679 unsigned int type_align
= TYPE_ALIGN (type
);
680 type_align
= MAX (type_align
, desired_align
);
681 if (maximum_field_alignment
!= 0)
682 type_align
= MIN (type_align
, maximum_field_alignment
);
683 rli
->record_align
= MAX (rli
->record_align
, type_align
);
684 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
687 #ifdef PCC_BITFIELD_TYPE_MATTERS
688 else if (is_bitfield
&& PCC_BITFIELD_TYPE_MATTERS
)
690 /* Named bit-fields cause the entire structure to have the
691 alignment implied by their type. Some targets also apply the same
692 rules to unnamed bitfields. */
693 if (DECL_NAME (field
) != 0
694 || targetm
.align_anon_bitfield ())
696 unsigned int type_align
= TYPE_ALIGN (type
);
698 #ifdef ADJUST_FIELD_ALIGN
699 if (! TYPE_USER_ALIGN (type
))
700 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
703 if (maximum_field_alignment
!= 0)
704 type_align
= MIN (type_align
, maximum_field_alignment
);
705 else if (DECL_PACKED (field
))
706 type_align
= MIN (type_align
, BITS_PER_UNIT
);
708 /* The alignment of the record is increased to the maximum
709 of the current alignment, the alignment indicated on the
710 field (i.e., the alignment specified by an __aligned__
711 attribute), and the alignment indicated by the type of
713 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
714 rli
->record_align
= MAX (rli
->record_align
, type_align
);
717 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
718 user_align
|= TYPE_USER_ALIGN (type
);
724 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
725 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
728 TYPE_USER_ALIGN (rli
->t
) |= user_align
;
730 return desired_align
;
733 /* Called from place_field to handle unions. */
736 place_union_field (record_layout_info rli
, tree field
)
738 update_alignment_for_field (rli
, field
, /*known_align=*/0);
740 DECL_FIELD_OFFSET (field
) = size_zero_node
;
741 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
742 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
744 /* We assume the union's size will be a multiple of a byte so we don't
745 bother with BITPOS. */
746 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
747 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
748 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
749 rli
->offset
= fold (build3 (COND_EXPR
, sizetype
,
750 DECL_QUALIFIER (field
),
751 DECL_SIZE_UNIT (field
), rli
->offset
));
754 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
755 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
756 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
757 units of alignment than the underlying TYPE. */
759 excess_unit_span (HOST_WIDE_INT byte_offset
, HOST_WIDE_INT bit_offset
,
760 HOST_WIDE_INT size
, HOST_WIDE_INT align
, tree type
)
762 /* Note that the calculation of OFFSET might overflow; we calculate it so
763 that we still get the right result as long as ALIGN is a power of two. */
764 unsigned HOST_WIDE_INT offset
= byte_offset
* BITS_PER_UNIT
+ bit_offset
;
766 offset
= offset
% align
;
767 return ((offset
+ size
+ align
- 1) / align
768 > ((unsigned HOST_WIDE_INT
) tree_low_cst (TYPE_SIZE (type
), 1)
773 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
774 is a FIELD_DECL to be added after those fields already present in
775 T. (FIELD is not actually added to the TYPE_FIELDS list here;
776 callers that desire that behavior must manually perform that step.) */
779 place_field (record_layout_info rli
, tree field
)
781 /* The alignment required for FIELD. */
782 unsigned int desired_align
;
783 /* The alignment FIELD would have if we just dropped it into the
784 record as it presently stands. */
785 unsigned int known_align
;
786 unsigned int actual_align
;
787 /* The type of this field. */
788 tree type
= TREE_TYPE (field
);
790 if (TREE_CODE (field
) == ERROR_MARK
|| TREE_CODE (type
) == ERROR_MARK
)
793 /* If FIELD is static, then treat it like a separate variable, not
794 really like a structure field. If it is a FUNCTION_DECL, it's a
795 method. In both cases, all we do is lay out the decl, and we do
796 it *after* the record is laid out. */
797 if (TREE_CODE (field
) == VAR_DECL
)
799 rli
->pending_statics
= tree_cons (NULL_TREE
, field
,
800 rli
->pending_statics
);
804 /* Enumerators and enum types which are local to this class need not
805 be laid out. Likewise for initialized constant fields. */
806 else if (TREE_CODE (field
) != FIELD_DECL
)
809 /* Unions are laid out very differently than records, so split
810 that code off to another function. */
811 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
813 place_union_field (rli
, field
);
817 /* Work out the known alignment so far. Note that A & (-A) is the
818 value of the least-significant bit in A that is one. */
819 if (! integer_zerop (rli
->bitpos
))
820 known_align
= (tree_low_cst (rli
->bitpos
, 1)
821 & - tree_low_cst (rli
->bitpos
, 1));
822 else if (integer_zerop (rli
->offset
))
823 known_align
= BIGGEST_ALIGNMENT
;
824 else if (host_integerp (rli
->offset
, 1))
825 known_align
= (BITS_PER_UNIT
826 * (tree_low_cst (rli
->offset
, 1)
827 & - tree_low_cst (rli
->offset
, 1)));
829 known_align
= rli
->offset_align
;
831 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
833 if (warn_packed
&& DECL_PACKED (field
))
835 if (known_align
>= TYPE_ALIGN (type
))
837 if (TYPE_ALIGN (type
) > desired_align
)
839 if (STRICT_ALIGNMENT
)
840 warning ("%Jpacked attribute causes inefficient alignment "
841 "for %qD", field
, field
);
843 warning ("%Jpacked attribute is unnecessary for %qD",
848 rli
->packed_maybe_necessary
= 1;
851 /* Does this field automatically have alignment it needs by virtue
852 of the fields that precede it and the record's own alignment? */
853 if (known_align
< desired_align
)
855 /* No, we need to skip space before this field.
856 Bump the cumulative size to multiple of field alignment. */
859 warning ("%Jpadding struct to align %qD", field
, field
);
861 /* If the alignment is still within offset_align, just align
863 if (desired_align
< rli
->offset_align
)
864 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
867 /* First adjust OFFSET by the partial bits, then align. */
869 = size_binop (PLUS_EXPR
, rli
->offset
,
870 fold_convert (sizetype
,
871 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
872 bitsize_unit_node
)));
873 rli
->bitpos
= bitsize_zero_node
;
875 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
878 if (! TREE_CONSTANT (rli
->offset
))
879 rli
->offset_align
= desired_align
;
883 /* Handle compatibility with PCC. Note that if the record has any
884 variable-sized fields, we need not worry about compatibility. */
885 #ifdef PCC_BITFIELD_TYPE_MATTERS
886 if (PCC_BITFIELD_TYPE_MATTERS
887 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
888 && TREE_CODE (field
) == FIELD_DECL
889 && type
!= error_mark_node
890 && DECL_BIT_FIELD (field
)
891 && ! DECL_PACKED (field
)
892 && maximum_field_alignment
== 0
893 && ! integer_zerop (DECL_SIZE (field
))
894 && host_integerp (DECL_SIZE (field
), 1)
895 && host_integerp (rli
->offset
, 1)
896 && host_integerp (TYPE_SIZE (type
), 1))
898 unsigned int type_align
= TYPE_ALIGN (type
);
899 tree dsize
= DECL_SIZE (field
);
900 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
901 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
902 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
904 #ifdef ADJUST_FIELD_ALIGN
905 if (! TYPE_USER_ALIGN (type
))
906 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
909 /* A bit field may not span more units of alignment of its type
910 than its type itself. Advance to next boundary if necessary. */
911 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
912 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
914 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
918 #ifdef BITFIELD_NBYTES_LIMITED
919 if (BITFIELD_NBYTES_LIMITED
920 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
921 && TREE_CODE (field
) == FIELD_DECL
922 && type
!= error_mark_node
923 && DECL_BIT_FIELD_TYPE (field
)
924 && ! DECL_PACKED (field
)
925 && ! integer_zerop (DECL_SIZE (field
))
926 && host_integerp (DECL_SIZE (field
), 1)
927 && host_integerp (rli
->offset
, 1)
928 && host_integerp (TYPE_SIZE (type
), 1))
930 unsigned int type_align
= TYPE_ALIGN (type
);
931 tree dsize
= DECL_SIZE (field
);
932 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
933 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
934 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
936 #ifdef ADJUST_FIELD_ALIGN
937 if (! TYPE_USER_ALIGN (type
))
938 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
941 if (maximum_field_alignment
!= 0)
942 type_align
= MIN (type_align
, maximum_field_alignment
);
943 /* ??? This test is opposite the test in the containing if
944 statement, so this code is unreachable currently. */
945 else if (DECL_PACKED (field
))
946 type_align
= MIN (type_align
, BITS_PER_UNIT
);
948 /* A bit field may not span the unit of alignment of its type.
949 Advance to next boundary if necessary. */
950 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
951 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
953 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
957 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
959 When a bit field is inserted into a packed record, the whole
960 size of the underlying type is used by one or more same-size
961 adjacent bitfields. (That is, if its long:3, 32 bits is
962 used in the record, and any additional adjacent long bitfields are
963 packed into the same chunk of 32 bits. However, if the size
964 changes, a new field of that size is allocated.) In an unpacked
965 record, this is the same as using alignment, but not equivalent
968 Note: for compatibility, we use the type size, not the type alignment
969 to determine alignment, since that matches the documentation */
971 if (targetm
.ms_bitfield_layout_p (rli
->t
)
972 && ((DECL_BIT_FIELD_TYPE (field
) && ! DECL_PACKED (field
))
973 || (rli
->prev_field
&& ! DECL_PACKED (rli
->prev_field
))))
975 /* At this point, either the prior or current are bitfields,
976 (possibly both), and we're dealing with MS packing. */
977 tree prev_saved
= rli
->prev_field
;
979 /* Is the prior field a bitfield? If so, handle "runs" of same
981 if (rli
->prev_field
/* necessarily a bitfield if it exists. */)
983 /* If both are bitfields, nonzero, and the same size, this is
984 the middle of a run. Zero declared size fields are special
985 and handled as "end of run". (Note: it's nonzero declared
986 size, but equal type sizes!) (Since we know that both
987 the current and previous fields are bitfields by the
988 time we check it, DECL_SIZE must be present for both.) */
989 if (DECL_BIT_FIELD_TYPE (field
)
990 && !integer_zerop (DECL_SIZE (field
))
991 && !integer_zerop (DECL_SIZE (rli
->prev_field
))
992 && host_integerp (DECL_SIZE (rli
->prev_field
), 0)
993 && host_integerp (TYPE_SIZE (type
), 0)
994 && simple_cst_equal (TYPE_SIZE (type
),
995 TYPE_SIZE (TREE_TYPE (rli
->prev_field
))))
997 /* We're in the middle of a run of equal type size fields; make
998 sure we realign if we run out of bits. (Not decl size,
1000 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 0);
1002 if (rli
->remaining_in_alignment
< bitsize
)
1004 /* out of bits; bump up to next 'word'. */
1005 rli
->offset
= DECL_FIELD_OFFSET (rli
->prev_field
);
1007 = size_binop (PLUS_EXPR
, TYPE_SIZE (type
),
1008 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1009 rli
->prev_field
= field
;
1010 rli
->remaining_in_alignment
1011 = tree_low_cst (TYPE_SIZE (type
), 0);
1014 rli
->remaining_in_alignment
-= bitsize
;
1018 /* End of a run: if leaving a run of bitfields of the same type
1019 size, we have to "use up" the rest of the bits of the type
1022 Compute the new position as the sum of the size for the prior
1023 type and where we first started working on that type.
1024 Note: since the beginning of the field was aligned then
1025 of course the end will be too. No round needed. */
1027 if (!integer_zerop (DECL_SIZE (rli
->prev_field
)))
1029 tree type_size
= TYPE_SIZE (TREE_TYPE (rli
->prev_field
));
1032 = size_binop (PLUS_EXPR
, type_size
,
1033 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1036 /* We "use up" size zero fields; the code below should behave
1037 as if the prior field was not a bitfield. */
1040 /* Cause a new bitfield to be captured, either this time (if
1041 currently a bitfield) or next time we see one. */
1042 if (!DECL_BIT_FIELD_TYPE(field
)
1043 || integer_zerop (DECL_SIZE (field
)))
1044 rli
->prev_field
= NULL
;
1047 normalize_rli (rli
);
1050 /* If we're starting a new run of same size type bitfields
1051 (or a run of non-bitfields), set up the "first of the run"
1054 That is, if the current field is not a bitfield, or if there
1055 was a prior bitfield the type sizes differ, or if there wasn't
1056 a prior bitfield the size of the current field is nonzero.
1058 Note: we must be sure to test ONLY the type size if there was
1059 a prior bitfield and ONLY for the current field being zero if
1062 if (!DECL_BIT_FIELD_TYPE (field
)
1063 || ( prev_saved
!= NULL
1064 ? !simple_cst_equal (TYPE_SIZE (type
),
1065 TYPE_SIZE (TREE_TYPE (prev_saved
)))
1066 : !integer_zerop (DECL_SIZE (field
)) ))
1068 /* Never smaller than a byte for compatibility. */
1069 unsigned int type_align
= BITS_PER_UNIT
;
1071 /* (When not a bitfield), we could be seeing a flex array (with
1072 no DECL_SIZE). Since we won't be using remaining_in_alignment
1073 until we see a bitfield (and come by here again) we just skip
1075 if (DECL_SIZE (field
) != NULL
1076 && host_integerp (TYPE_SIZE (TREE_TYPE (field
)), 0)
1077 && host_integerp (DECL_SIZE (field
), 0))
1078 rli
->remaining_in_alignment
1079 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field
)), 0)
1080 - tree_low_cst (DECL_SIZE (field
), 0);
1082 /* Now align (conventionally) for the new type. */
1083 if (!DECL_PACKED(field
))
1084 type_align
= MAX(TYPE_ALIGN (type
), type_align
);
1087 && DECL_BIT_FIELD_TYPE (prev_saved
)
1088 /* If the previous bit-field is zero-sized, we've already
1089 accounted for its alignment needs (or ignored it, if
1090 appropriate) while placing it. */
1091 && ! integer_zerop (DECL_SIZE (prev_saved
)))
1092 type_align
= MAX (type_align
,
1093 TYPE_ALIGN (TREE_TYPE (prev_saved
)));
1095 if (maximum_field_alignment
!= 0)
1096 type_align
= MIN (type_align
, maximum_field_alignment
);
1098 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1100 /* If we really aligned, don't allow subsequent bitfields
1102 rli
->prev_field
= NULL
;
1106 /* Offset so far becomes the position of this field after normalizing. */
1107 normalize_rli (rli
);
1108 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1109 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1110 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1112 /* If this field ended up more aligned than we thought it would be (we
1113 approximate this by seeing if its position changed), lay out the field
1114 again; perhaps we can use an integral mode for it now. */
1115 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
1116 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
1117 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
1118 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
1119 actual_align
= BIGGEST_ALIGNMENT
;
1120 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
1121 actual_align
= (BITS_PER_UNIT
1122 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
1123 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
1125 actual_align
= DECL_OFFSET_ALIGN (field
);
1127 if (known_align
!= actual_align
)
1128 layout_decl (field
, actual_align
);
1130 /* Only the MS bitfields use this. */
1131 if (rli
->prev_field
== NULL
&& DECL_BIT_FIELD_TYPE(field
))
1132 rli
->prev_field
= field
;
1134 /* Now add size of this field to the size of the record. If the size is
1135 not constant, treat the field as being a multiple of bytes and just
1136 adjust the offset, resetting the bit position. Otherwise, apportion the
1137 size amongst the bit position and offset. First handle the case of an
1138 unspecified size, which can happen when we have an invalid nested struct
1139 definition, such as struct j { struct j { int i; } }. The error message
1140 is printed in finish_struct. */
1141 if (DECL_SIZE (field
) == 0)
1143 else if (TREE_CODE (DECL_SIZE_UNIT (field
)) != INTEGER_CST
1144 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field
)))
1147 = size_binop (PLUS_EXPR
, rli
->offset
,
1148 fold_convert (sizetype
,
1149 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1150 bitsize_unit_node
)));
1152 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1153 rli
->bitpos
= bitsize_zero_node
;
1154 rli
->offset_align
= MIN (rli
->offset_align
, desired_align
);
1158 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1159 normalize_rli (rli
);
1163 /* Assuming that all the fields have been laid out, this function uses
1164 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1165 indicated by RLI. */
1168 finalize_record_size (record_layout_info rli
)
1170 tree unpadded_size
, unpadded_size_unit
;
1172 /* Now we want just byte and bit offsets, so set the offset alignment
1173 to be a byte and then normalize. */
1174 rli
->offset_align
= BITS_PER_UNIT
;
1175 normalize_rli (rli
);
1177 /* Determine the desired alignment. */
1178 #ifdef ROUND_TYPE_ALIGN
1179 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
1182 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
1185 /* Compute the size so far. Be sure to allow for extra bits in the
1186 size in bytes. We have guaranteed above that it will be no more
1187 than a single byte. */
1188 unpadded_size
= rli_size_so_far (rli
);
1189 unpadded_size_unit
= rli_size_unit_so_far (rli
);
1190 if (! integer_zerop (rli
->bitpos
))
1192 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
1194 /* Round the size up to be a multiple of the required alignment. */
1195 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
1196 TYPE_SIZE_UNIT (rli
->t
)
1197 = round_up (unpadded_size_unit
, TYPE_ALIGN_UNIT (rli
->t
));
1199 if (warn_padded
&& TREE_CONSTANT (unpadded_size
)
1200 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0)
1201 warning ("padding struct size to alignment boundary");
1203 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
1204 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
1205 && TREE_CONSTANT (unpadded_size
))
1209 #ifdef ROUND_TYPE_ALIGN
1211 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1213 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1216 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
1217 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
1219 TYPE_PACKED (rli
->t
) = 0;
1221 if (TYPE_NAME (rli
->t
))
1225 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1226 name
= IDENTIFIER_POINTER (TYPE_NAME (rli
->t
));
1228 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli
->t
)));
1230 if (STRICT_ALIGNMENT
)
1231 warning ("packed attribute causes inefficient "
1232 "alignment for %qs", name
);
1234 warning ("packed attribute is unnecessary for %qs", name
);
1238 if (STRICT_ALIGNMENT
)
1239 warning ("packed attribute causes inefficient alignment");
1241 warning ("packed attribute is unnecessary");
1247 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1250 compute_record_mode (tree type
)
1253 enum machine_mode mode
= VOIDmode
;
1255 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1256 However, if possible, we use a mode that fits in a register
1257 instead, in order to allow for better optimization down the
1259 TYPE_MODE (type
) = BLKmode
;
1261 if (! host_integerp (TYPE_SIZE (type
), 1))
1264 /* A record which has any BLKmode members must itself be
1265 BLKmode; it can't go in a register. Unless the member is
1266 BLKmode only because it isn't aligned. */
1267 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1269 if (TREE_CODE (field
) != FIELD_DECL
)
1272 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1273 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1274 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
))
1275 && !(TYPE_SIZE (TREE_TYPE (field
)) != 0
1276 && integer_zerop (TYPE_SIZE (TREE_TYPE (field
)))))
1277 || ! host_integerp (bit_position (field
), 1)
1278 || DECL_SIZE (field
) == 0
1279 || ! host_integerp (DECL_SIZE (field
), 1))
1282 /* If this field is the whole struct, remember its mode so
1283 that, say, we can put a double in a class into a DF
1284 register instead of forcing it to live in the stack. */
1285 if (simple_cst_equal (TYPE_SIZE (type
), DECL_SIZE (field
)))
1286 mode
= DECL_MODE (field
);
1288 #ifdef MEMBER_TYPE_FORCES_BLK
1289 /* With some targets, eg. c4x, it is sub-optimal
1290 to access an aligned BLKmode structure as a scalar. */
1292 if (MEMBER_TYPE_FORCES_BLK (field
, mode
))
1294 #endif /* MEMBER_TYPE_FORCES_BLK */
1297 TYPE_MODE (type
) = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1299 /* If we only have one real field; use its mode if that mode's size
1300 matches the type's size. This only applies to RECORD_TYPE. This
1301 does not apply to unions. */
1302 if (TREE_CODE (type
) == RECORD_TYPE
&& mode
!= VOIDmode
1303 && GET_MODE_SIZE (mode
) == GET_MODE_SIZE (TYPE_MODE (type
)))
1304 TYPE_MODE (type
) = mode
;
1306 /* If structure's known alignment is less than what the scalar
1307 mode would need, and it matters, then stick with BLKmode. */
1308 if (TYPE_MODE (type
) != BLKmode
1310 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1311 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1313 /* If this is the only reason this type is BLKmode, then
1314 don't force containing types to be BLKmode. */
1315 TYPE_NO_FORCE_BLK (type
) = 1;
1316 TYPE_MODE (type
) = BLKmode
;
1320 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1324 finalize_type_size (tree type
)
1326 /* Normally, use the alignment corresponding to the mode chosen.
1327 However, where strict alignment is not required, avoid
1328 over-aligning structures, since most compilers do not do this
1331 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1332 && (STRICT_ALIGNMENT
1333 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1334 && TREE_CODE (type
) != QUAL_UNION_TYPE
1335 && TREE_CODE (type
) != ARRAY_TYPE
)))
1337 TYPE_ALIGN (type
) = GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1338 TYPE_USER_ALIGN (type
) = 0;
1341 /* Do machine-dependent extra alignment. */
1342 #ifdef ROUND_TYPE_ALIGN
1344 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1347 /* If we failed to find a simple way to calculate the unit size
1348 of the type, find it by division. */
1349 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1350 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1351 result will fit in sizetype. We will get more efficient code using
1352 sizetype, so we force a conversion. */
1353 TYPE_SIZE_UNIT (type
)
1354 = fold_convert (sizetype
,
1355 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1356 bitsize_unit_node
));
1358 if (TYPE_SIZE (type
) != 0)
1360 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1361 TYPE_SIZE_UNIT (type
) = round_up (TYPE_SIZE_UNIT (type
),
1362 TYPE_ALIGN_UNIT (type
));
1365 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1366 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1367 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1368 if (TYPE_SIZE_UNIT (type
) != 0
1369 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1370 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1372 /* Also layout any other variants of the type. */
1373 if (TYPE_NEXT_VARIANT (type
)
1374 || type
!= TYPE_MAIN_VARIANT (type
))
1377 /* Record layout info of this variant. */
1378 tree size
= TYPE_SIZE (type
);
1379 tree size_unit
= TYPE_SIZE_UNIT (type
);
1380 unsigned int align
= TYPE_ALIGN (type
);
1381 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1382 enum machine_mode mode
= TYPE_MODE (type
);
1384 /* Copy it into all variants. */
1385 for (variant
= TYPE_MAIN_VARIANT (type
);
1387 variant
= TYPE_NEXT_VARIANT (variant
))
1389 TYPE_SIZE (variant
) = size
;
1390 TYPE_SIZE_UNIT (variant
) = size_unit
;
1391 TYPE_ALIGN (variant
) = align
;
1392 TYPE_USER_ALIGN (variant
) = user_align
;
1393 TYPE_MODE (variant
) = mode
;
1398 /* Do all of the work required to layout the type indicated by RLI,
1399 once the fields have been laid out. This function will call `free'
1400 for RLI, unless FREE_P is false. Passing a value other than false
1401 for FREE_P is bad practice; this option only exists to support the
1405 finish_record_layout (record_layout_info rli
, int free_p
)
1407 /* Compute the final size. */
1408 finalize_record_size (rli
);
1410 /* Compute the TYPE_MODE for the record. */
1411 compute_record_mode (rli
->t
);
1413 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1414 finalize_type_size (rli
->t
);
1416 /* Lay out any static members. This is done now because their type
1417 may use the record's type. */
1418 while (rli
->pending_statics
)
1420 layout_decl (TREE_VALUE (rli
->pending_statics
), 0);
1421 rli
->pending_statics
= TREE_CHAIN (rli
->pending_statics
);
1430 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1431 NAME, its fields are chained in reverse on FIELDS.
1433 If ALIGN_TYPE is non-null, it is given the same alignment as
1437 finish_builtin_struct (tree type
, const char *name
, tree fields
,
1442 for (tail
= NULL_TREE
; fields
; tail
= fields
, fields
= next
)
1444 DECL_FIELD_CONTEXT (fields
) = type
;
1445 next
= TREE_CHAIN (fields
);
1446 TREE_CHAIN (fields
) = tail
;
1448 TYPE_FIELDS (type
) = tail
;
1452 TYPE_ALIGN (type
) = TYPE_ALIGN (align_type
);
1453 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (align_type
);
1457 #if 0 /* not yet, should get fixed properly later */
1458 TYPE_NAME (type
) = make_type_decl (get_identifier (name
), type
);
1460 TYPE_NAME (type
) = build_decl (TYPE_DECL
, get_identifier (name
), type
);
1462 TYPE_STUB_DECL (type
) = TYPE_NAME (type
);
1463 layout_decl (TYPE_NAME (type
), 0);
1466 /* Calculate the mode, size, and alignment for TYPE.
1467 For an array type, calculate the element separation as well.
1468 Record TYPE on the chain of permanent or temporary types
1469 so that dbxout will find out about it.
1471 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1472 layout_type does nothing on such a type.
1474 If the type is incomplete, its TYPE_SIZE remains zero. */
1477 layout_type (tree type
)
1481 if (type
== error_mark_node
)
1484 /* Do nothing if type has been laid out before. */
1485 if (TYPE_SIZE (type
))
1488 switch (TREE_CODE (type
))
1491 /* This kind of type is the responsibility
1492 of the language-specific code. */
1495 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1496 if (TYPE_PRECISION (type
) == 0)
1497 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1499 /* ... fall through ... */
1504 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1505 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1506 TYPE_UNSIGNED (type
) = 1;
1508 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
1510 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1511 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1515 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
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_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1523 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1524 (TREE_CODE (TREE_TYPE (type
)) == REAL_TYPE
1525 ? MODE_COMPLEX_FLOAT
: MODE_COMPLEX_INT
),
1527 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1528 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1533 int nunits
= TYPE_VECTOR_SUBPARTS (type
);
1534 tree nunits_tree
= build_int_cst (NULL_TREE
, nunits
);
1535 tree innertype
= TREE_TYPE (type
);
1537 gcc_assert (!(nunits
& (nunits
- 1)));
1539 /* Find an appropriate mode for the vector type. */
1540 if (TYPE_MODE (type
) == VOIDmode
)
1542 enum machine_mode innermode
= TYPE_MODE (innertype
);
1543 enum machine_mode mode
;
1545 /* First, look for a supported vector type. */
1546 if (GET_MODE_CLASS (innermode
) == MODE_FLOAT
)
1547 mode
= MIN_MODE_VECTOR_FLOAT
;
1549 mode
= MIN_MODE_VECTOR_INT
;
1551 for (; mode
!= VOIDmode
; mode
= GET_MODE_WIDER_MODE (mode
))
1552 if (GET_MODE_NUNITS (mode
) == nunits
1553 && GET_MODE_INNER (mode
) == innermode
1554 && targetm
.vector_mode_supported_p (mode
))
1557 /* For integers, try mapping it to a same-sized scalar mode. */
1558 if (mode
== VOIDmode
1559 && GET_MODE_CLASS (innermode
) == MODE_INT
)
1560 mode
= mode_for_size (nunits
* GET_MODE_BITSIZE (innermode
),
1563 if (mode
== VOIDmode
|| !have_regs_of_mode
[mode
])
1564 TYPE_MODE (type
) = BLKmode
;
1566 TYPE_MODE (type
) = mode
;
1569 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1570 TYPE_SIZE_UNIT (type
) = int_const_binop (MULT_EXPR
,
1571 TYPE_SIZE_UNIT (innertype
),
1573 TYPE_SIZE (type
) = int_const_binop (MULT_EXPR
, TYPE_SIZE (innertype
),
1576 /* Always naturally align vectors. This prevents ABI changes
1577 depending on whether or not native vector modes are supported. */
1578 TYPE_ALIGN (type
) = tree_low_cst (TYPE_SIZE (type
), 0);
1583 /* This is an incomplete type and so doesn't have a size. */
1584 TYPE_ALIGN (type
) = 1;
1585 TYPE_USER_ALIGN (type
) = 0;
1586 TYPE_MODE (type
) = VOIDmode
;
1590 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1591 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1592 /* A pointer might be MODE_PARTIAL_INT,
1593 but ptrdiff_t must be integral. */
1594 TYPE_MODE (type
) = mode_for_size (POINTER_SIZE
, MODE_INT
, 0);
1599 /* It's hard to see what the mode and size of a function ought to
1600 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1601 make it consistent with that. */
1602 TYPE_MODE (type
) = mode_for_size (FUNCTION_BOUNDARY
, MODE_INT
, 0);
1603 TYPE_SIZE (type
) = bitsize_int (FUNCTION_BOUNDARY
);
1604 TYPE_SIZE_UNIT (type
) = size_int (FUNCTION_BOUNDARY
/ BITS_PER_UNIT
);
1608 case REFERENCE_TYPE
:
1611 enum machine_mode mode
= ((TREE_CODE (type
) == REFERENCE_TYPE
1612 && reference_types_internal
)
1613 ? Pmode
: TYPE_MODE (type
));
1615 int nbits
= GET_MODE_BITSIZE (mode
);
1617 TYPE_SIZE (type
) = bitsize_int (nbits
);
1618 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (mode
));
1619 TYPE_UNSIGNED (type
) = 1;
1620 TYPE_PRECISION (type
) = nbits
;
1626 tree index
= TYPE_DOMAIN (type
);
1627 tree element
= TREE_TYPE (type
);
1629 build_pointer_type (element
);
1631 /* We need to know both bounds in order to compute the size. */
1632 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1633 && TYPE_SIZE (element
))
1635 tree ub
= TYPE_MAX_VALUE (index
);
1636 tree lb
= TYPE_MIN_VALUE (index
);
1640 /* The initial subtraction should happen in the original type so
1641 that (possible) negative values are handled appropriately. */
1642 length
= size_binop (PLUS_EXPR
, size_one_node
,
1643 fold_convert (sizetype
,
1644 fold (build2 (MINUS_EXPR
,
1648 /* Special handling for arrays of bits (for Chill). */
1649 element_size
= TYPE_SIZE (element
);
1650 if (TYPE_PACKED (type
) && INTEGRAL_TYPE_P (element
)
1651 && (integer_zerop (TYPE_MAX_VALUE (element
))
1652 || integer_onep (TYPE_MAX_VALUE (element
)))
1653 && host_integerp (TYPE_MIN_VALUE (element
), 1))
1655 HOST_WIDE_INT maxvalue
1656 = tree_low_cst (TYPE_MAX_VALUE (element
), 1);
1657 HOST_WIDE_INT minvalue
1658 = tree_low_cst (TYPE_MIN_VALUE (element
), 1);
1660 if (maxvalue
- minvalue
== 1
1661 && (maxvalue
== 1 || maxvalue
== 0))
1662 element_size
= integer_one_node
;
1665 /* If neither bound is a constant and sizetype is signed, make
1666 sure the size is never negative. We should really do this
1667 if *either* bound is non-constant, but this is the best
1668 compromise between C and Ada. */
1669 if (!TYPE_UNSIGNED (sizetype
)
1670 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
1671 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
1672 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
1674 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1675 fold_convert (bitsizetype
,
1678 /* If we know the size of the element, calculate the total
1679 size directly, rather than do some division thing below.
1680 This optimization helps Fortran assumed-size arrays
1681 (where the size of the array is determined at runtime)
1683 Note that we can't do this in the case where the size of
1684 the elements is one bit since TYPE_SIZE_UNIT cannot be
1685 set correctly in that case. */
1686 if (TYPE_SIZE_UNIT (element
) != 0 && ! integer_onep (element_size
))
1687 TYPE_SIZE_UNIT (type
)
1688 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1691 /* Now round the alignment and size,
1692 using machine-dependent criteria if any. */
1694 #ifdef ROUND_TYPE_ALIGN
1696 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1698 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1700 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (element
);
1701 TYPE_MODE (type
) = BLKmode
;
1702 if (TYPE_SIZE (type
) != 0
1703 #ifdef MEMBER_TYPE_FORCES_BLK
1704 && ! MEMBER_TYPE_FORCES_BLK (type
, VOIDmode
)
1706 /* BLKmode elements force BLKmode aggregate;
1707 else extract/store fields may lose. */
1708 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
1709 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
1711 /* One-element arrays get the component type's mode. */
1712 if (simple_cst_equal (TYPE_SIZE (type
),
1713 TYPE_SIZE (TREE_TYPE (type
))))
1714 TYPE_MODE (type
) = TYPE_MODE (TREE_TYPE (type
));
1717 = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1719 if (TYPE_MODE (type
) != BLKmode
1720 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
1721 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
))
1722 && TYPE_MODE (type
) != BLKmode
)
1724 TYPE_NO_FORCE_BLK (type
) = 1;
1725 TYPE_MODE (type
) = BLKmode
;
1733 case QUAL_UNION_TYPE
:
1736 record_layout_info rli
;
1738 /* Initialize the layout information. */
1739 rli
= start_record_layout (type
);
1741 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1742 in the reverse order in building the COND_EXPR that denotes
1743 its size. We reverse them again later. */
1744 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1745 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1747 /* Place all the fields. */
1748 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1749 place_field (rli
, field
);
1751 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1752 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1754 if (lang_adjust_rli
)
1755 (*lang_adjust_rli
) (rli
);
1757 /* Finish laying out the record. */
1758 finish_record_layout (rli
, /*free_p=*/true);
1763 /* The size may vary in different languages, so the language front end
1764 should fill in the size. */
1765 TYPE_ALIGN (type
) = BIGGEST_ALIGNMENT
;
1766 TYPE_USER_ALIGN (type
) = 0;
1767 TYPE_MODE (type
) = BLKmode
;
1774 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1775 records and unions, finish_record_layout already called this
1777 if (TREE_CODE (type
) != RECORD_TYPE
1778 && TREE_CODE (type
) != UNION_TYPE
1779 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
1780 finalize_type_size (type
);
1782 /* If an alias set has been set for this aggregate when it was incomplete,
1783 force it into alias set 0.
1784 This is too conservative, but we cannot call record_component_aliases
1785 here because some frontends still change the aggregates after
1787 if (AGGREGATE_TYPE_P (type
) && TYPE_ALIAS_SET_KNOWN_P (type
))
1788 TYPE_ALIAS_SET (type
) = 0;
1791 /* Create and return a type for signed integers of PRECISION bits. */
1794 make_signed_type (int precision
)
1796 tree type
= make_node (INTEGER_TYPE
);
1798 TYPE_PRECISION (type
) = precision
;
1800 fixup_signed_type (type
);
1804 /* Create and return a type for unsigned integers of PRECISION bits. */
1807 make_unsigned_type (int precision
)
1809 tree type
= make_node (INTEGER_TYPE
);
1811 TYPE_PRECISION (type
) = precision
;
1813 fixup_unsigned_type (type
);
1817 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1818 value to enable integer types to be created. */
1821 initialize_sizetypes (bool signed_p
)
1823 tree t
= make_node (INTEGER_TYPE
);
1825 TYPE_MODE (t
) = SImode
;
1826 TYPE_ALIGN (t
) = GET_MODE_ALIGNMENT (SImode
);
1827 TYPE_USER_ALIGN (t
) = 0;
1828 TYPE_IS_SIZETYPE (t
) = 1;
1829 TYPE_UNSIGNED (t
) = !signed_p
;
1830 TYPE_SIZE (t
) = build_int_cst (t
, GET_MODE_BITSIZE (SImode
));
1831 TYPE_SIZE_UNIT (t
) = build_int_cst (t
, GET_MODE_SIZE (SImode
));
1832 TYPE_PRECISION (t
) = GET_MODE_BITSIZE (SImode
);
1833 TYPE_MIN_VALUE (t
) = build_int_cst (t
, 0);
1835 /* 1000 avoids problems with possible overflow and is certainly
1836 larger than any size value we'd want to be storing. */
1837 TYPE_MAX_VALUE (t
) = build_int_cst (t
, 1000);
1840 bitsizetype
= build_distinct_type_copy (t
);
1843 /* Make sizetype a version of TYPE, and initialize *sizetype
1844 accordingly. We do this by overwriting the stub sizetype and
1845 bitsizetype nodes created by initialize_sizetypes. This makes sure
1846 that (a) anything stubby about them no longer exists, (b) any
1847 INTEGER_CSTs created with such a type, remain valid. */
1850 set_sizetype (tree type
)
1852 int oprecision
= TYPE_PRECISION (type
);
1853 /* The *bitsizetype types use a precision that avoids overflows when
1854 calculating signed sizes / offsets in bits. However, when
1855 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1857 int precision
= MIN (oprecision
+ BITS_PER_UNIT_LOG
+ 1,
1858 2 * HOST_BITS_PER_WIDE_INT
);
1861 gcc_assert (TYPE_UNSIGNED (type
) == TYPE_UNSIGNED (sizetype
));
1863 t
= build_distinct_type_copy (type
);
1864 /* We do want to use sizetype's cache, as we will be replacing that
1866 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (sizetype
);
1867 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (sizetype
);
1868 TREE_TYPE (TYPE_CACHED_VALUES (t
)) = type
;
1869 TYPE_UID (t
) = TYPE_UID (sizetype
);
1870 TYPE_IS_SIZETYPE (t
) = 1;
1872 /* Replace our original stub sizetype. */
1873 memcpy (sizetype
, t
, tree_size (sizetype
));
1874 TYPE_MAIN_VARIANT (sizetype
) = sizetype
;
1876 t
= make_node (INTEGER_TYPE
);
1877 TYPE_NAME (t
) = get_identifier ("bit_size_type");
1878 /* We do want to use bitsizetype's cache, as we will be replacing that
1880 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (bitsizetype
);
1881 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (bitsizetype
);
1882 TYPE_PRECISION (t
) = precision
;
1883 TYPE_UID (t
) = TYPE_UID (bitsizetype
);
1884 TYPE_IS_SIZETYPE (t
) = 1;
1885 /* Replace our original stub bitsizetype. */
1886 memcpy (bitsizetype
, t
, tree_size (bitsizetype
));
1888 if (TYPE_UNSIGNED (type
))
1890 fixup_unsigned_type (bitsizetype
);
1891 ssizetype
= build_distinct_type_copy (make_signed_type (oprecision
));
1892 TYPE_IS_SIZETYPE (ssizetype
) = 1;
1893 sbitsizetype
= build_distinct_type_copy (make_signed_type (precision
));
1894 TYPE_IS_SIZETYPE (sbitsizetype
) = 1;
1898 fixup_signed_type (bitsizetype
);
1899 ssizetype
= sizetype
;
1900 sbitsizetype
= bitsizetype
;
1904 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1905 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1906 for TYPE, based on the PRECISION and whether or not the TYPE
1907 IS_UNSIGNED. PRECISION need not correspond to a width supported
1908 natively by the hardware; for example, on a machine with 8-bit,
1909 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1913 set_min_and_max_values_for_integral_type (tree type
,
1922 min_value
= build_int_cst (type
, 0);
1924 = build_int_cst_wide (type
, precision
- HOST_BITS_PER_WIDE_INT
>= 0
1926 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
1927 precision
- HOST_BITS_PER_WIDE_INT
> 0
1928 ? ((unsigned HOST_WIDE_INT
) ~0
1929 >> (HOST_BITS_PER_WIDE_INT
1930 - (precision
- HOST_BITS_PER_WIDE_INT
)))
1936 = build_int_cst_wide (type
,
1937 (precision
- HOST_BITS_PER_WIDE_INT
> 0
1939 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
1940 (((HOST_WIDE_INT
) (-1)
1941 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1942 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
1945 = build_int_cst_wide (type
,
1946 (precision
- HOST_BITS_PER_WIDE_INT
> 0
1948 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
1949 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1950 ? (((HOST_WIDE_INT
) 1
1951 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
1955 TYPE_MIN_VALUE (type
) = min_value
;
1956 TYPE_MAX_VALUE (type
) = max_value
;
1959 /* Set the extreme values of TYPE based on its precision in bits,
1960 then lay it out. Used when make_signed_type won't do
1961 because the tree code is not INTEGER_TYPE.
1962 E.g. for Pascal, when the -fsigned-char option is given. */
1965 fixup_signed_type (tree type
)
1967 int precision
= TYPE_PRECISION (type
);
1969 /* We can not represent properly constants greater then
1970 2 * HOST_BITS_PER_WIDE_INT, still we need the types
1971 as they are used by i386 vector extensions and friends. */
1972 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
1973 precision
= HOST_BITS_PER_WIDE_INT
* 2;
1975 set_min_and_max_values_for_integral_type (type
, precision
,
1976 /*is_unsigned=*/false);
1978 /* Lay out the type: set its alignment, size, etc. */
1982 /* Set the extreme values of TYPE based on its precision in bits,
1983 then lay it out. This is used both in `make_unsigned_type'
1984 and for enumeral types. */
1987 fixup_unsigned_type (tree type
)
1989 int precision
= TYPE_PRECISION (type
);
1991 /* We can not represent properly constants greater then
1992 2 * HOST_BITS_PER_WIDE_INT, still we need the types
1993 as they are used by i386 vector extensions and friends. */
1994 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
1995 precision
= HOST_BITS_PER_WIDE_INT
* 2;
1997 TYPE_UNSIGNED (type
) = 1;
1999 set_min_and_max_values_for_integral_type (type
, precision
,
2000 /*is_unsigned=*/true);
2002 /* Lay out the type: set its alignment, size, etc. */
2006 /* Find the best machine mode to use when referencing a bit field of length
2007 BITSIZE bits starting at BITPOS.
2009 The underlying object is known to be aligned to a boundary of ALIGN bits.
2010 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2011 larger than LARGEST_MODE (usually SImode).
2013 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2014 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2015 mode meeting these conditions.
2017 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2018 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2019 all the conditions. */
2022 get_best_mode (int bitsize
, int bitpos
, unsigned int align
,
2023 enum machine_mode largest_mode
, int volatilep
)
2025 enum machine_mode mode
;
2026 unsigned int unit
= 0;
2028 /* Find the narrowest integer mode that contains the bit field. */
2029 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
2030 mode
= GET_MODE_WIDER_MODE (mode
))
2032 unit
= GET_MODE_BITSIZE (mode
);
2033 if ((bitpos
% unit
) + bitsize
<= unit
)
2037 if (mode
== VOIDmode
2038 /* It is tempting to omit the following line
2039 if STRICT_ALIGNMENT is true.
2040 But that is incorrect, since if the bitfield uses part of 3 bytes
2041 and we use a 4-byte mode, we could get a spurious segv
2042 if the extra 4th byte is past the end of memory.
2043 (Though at least one Unix compiler ignores this problem:
2044 that on the Sequent 386 machine. */
2045 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
2046 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
2049 if (SLOW_BYTE_ACCESS
&& ! volatilep
)
2051 enum machine_mode wide_mode
= VOIDmode
, tmode
;
2053 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
2054 tmode
= GET_MODE_WIDER_MODE (tmode
))
2056 unit
= GET_MODE_BITSIZE (tmode
);
2057 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
2058 && unit
<= BITS_PER_WORD
2059 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
2060 && (largest_mode
== VOIDmode
2061 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
2065 if (wide_mode
!= VOIDmode
)
2072 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2073 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2076 get_mode_bounds (enum machine_mode mode
, int sign
,
2077 enum machine_mode target_mode
,
2078 rtx
*mmin
, rtx
*mmax
)
2080 unsigned size
= GET_MODE_BITSIZE (mode
);
2081 unsigned HOST_WIDE_INT min_val
, max_val
;
2083 gcc_assert (size
<= HOST_BITS_PER_WIDE_INT
);
2087 min_val
= -((unsigned HOST_WIDE_INT
) 1 << (size
- 1));
2088 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1)) - 1;
2093 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1) << 1) - 1;
2096 *mmin
= gen_int_mode (min_val
, target_mode
);
2097 *mmax
= gen_int_mode (max_val
, target_mode
);
2100 #include "gt-stor-layout.h"