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 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
51 May be overridden by front-ends. */
52 unsigned int set_alignment
= 0;
54 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
55 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
56 called only by a front end. */
57 static int reference_types_internal
= 0;
59 static void finalize_record_size (record_layout_info
);
60 static void finalize_type_size (tree
);
61 static void place_union_field (record_layout_info
, tree
);
62 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
63 static int excess_unit_span (HOST_WIDE_INT
, HOST_WIDE_INT
, HOST_WIDE_INT
,
66 extern void debug_rli (record_layout_info
);
68 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
70 static GTY(()) tree pending_sizes
;
72 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
76 internal_reference_types (void)
78 reference_types_internal
= 1;
81 /* Get a list of all the objects put on the pending sizes list. */
84 get_pending_sizes (void)
86 tree chain
= pending_sizes
;
92 /* Add EXPR to the pending sizes list. */
95 put_pending_size (tree expr
)
97 /* Strip any simple arithmetic from EXPR to see if it has an underlying
99 expr
= skip_simple_arithmetic (expr
);
101 if (TREE_CODE (expr
) == SAVE_EXPR
)
102 pending_sizes
= tree_cons (NULL_TREE
, expr
, pending_sizes
);
105 /* Put a chain of objects into the pending sizes list, which must be
109 put_pending_sizes (tree chain
)
111 gcc_assert (!pending_sizes
);
112 pending_sizes
= chain
;
115 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
116 to serve as the actual size-expression for a type or decl. */
119 variable_size (tree size
)
123 /* If the language-processor is to take responsibility for variable-sized
124 items (e.g., languages which have elaboration procedures like Ada),
125 just return SIZE unchanged. Likewise for self-referential sizes and
127 if (TREE_CONSTANT (size
)
128 || lang_hooks
.decls
.global_bindings_p () < 0
129 || CONTAINS_PLACEHOLDER_P (size
))
132 size
= save_expr (size
);
134 /* If an array with a variable number of elements is declared, and
135 the elements require destruction, we will emit a cleanup for the
136 array. That cleanup is run both on normal exit from the block
137 and in the exception-handler for the block. Normally, when code
138 is used in both ordinary code and in an exception handler it is
139 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
140 not wish to do that here; the array-size is the same in both
142 save
= skip_simple_arithmetic (size
);
144 if (cfun
&& cfun
->x_dont_save_pending_sizes_p
)
145 /* The front-end doesn't want us to keep a list of the expressions
146 that determine sizes for variable size objects. Trust it. */
149 if (lang_hooks
.decls
.global_bindings_p ())
151 if (TREE_CONSTANT (size
))
152 error ("type size can't be explicitly evaluated");
154 error ("variable-size type declared outside of any function");
156 return size_one_node
;
159 put_pending_size (save
);
164 #ifndef MAX_FIXED_MODE_SIZE
165 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
168 /* Return the machine mode to use for a nonscalar of SIZE bits. The
169 mode must be in class CLASS, and have exactly that many value bits;
170 it may have padding as well. If LIMIT is nonzero, modes of wider
171 than MAX_FIXED_MODE_SIZE will not be used. */
174 mode_for_size (unsigned int size
, enum mode_class
class, int limit
)
176 enum machine_mode mode
;
178 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
181 /* Get the first mode which has this size, in the specified class. */
182 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
183 mode
= GET_MODE_WIDER_MODE (mode
))
184 if (GET_MODE_PRECISION (mode
) == size
)
190 /* Similar, except passed a tree node. */
193 mode_for_size_tree (tree size
, enum mode_class
class, int limit
)
195 if (TREE_CODE (size
) != INTEGER_CST
196 || TREE_OVERFLOW (size
)
197 /* What we really want to say here is that the size can fit in a
198 host integer, but we know there's no way we'd find a mode for
199 this many bits, so there's no point in doing the precise test. */
200 || compare_tree_int (size
, 1000) > 0)
203 return mode_for_size (tree_low_cst (size
, 1), class, limit
);
206 /* Similar, but never return BLKmode; return the narrowest mode that
207 contains at least the requested number of value bits. */
210 smallest_mode_for_size (unsigned int size
, enum mode_class
class)
212 enum machine_mode mode
;
214 /* Get the first mode which has at least this size, in the
216 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
217 mode
= GET_MODE_WIDER_MODE (mode
))
218 if (GET_MODE_PRECISION (mode
) >= size
)
224 /* Find an integer mode of the exact same size, or BLKmode on failure. */
227 int_mode_for_mode (enum machine_mode mode
)
229 switch (GET_MODE_CLASS (mode
))
232 case MODE_PARTIAL_INT
:
235 case MODE_COMPLEX_INT
:
236 case MODE_COMPLEX_FLOAT
:
238 case MODE_VECTOR_INT
:
239 case MODE_VECTOR_FLOAT
:
240 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
247 /* ... fall through ... */
257 /* Return the alignment of MODE. This will be bounded by 1 and
258 BIGGEST_ALIGNMENT. */
261 get_mode_alignment (enum machine_mode mode
)
263 return MIN (BIGGEST_ALIGNMENT
, MAX (1, mode_base_align
[mode
]*BITS_PER_UNIT
));
267 /* Subroutine of layout_decl: Force alignment required for the data type.
268 But if the decl itself wants greater alignment, don't override that. */
271 do_type_align (tree type
, tree decl
)
273 if (TYPE_ALIGN (type
) > DECL_ALIGN (decl
))
275 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
276 if (TREE_CODE (decl
) == FIELD_DECL
)
277 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
281 /* Set the size, mode and alignment of a ..._DECL node.
282 TYPE_DECL does need this for C++.
283 Note that LABEL_DECL and CONST_DECL nodes do not need this,
284 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
285 Don't call layout_decl for them.
287 KNOWN_ALIGN is the amount of alignment we can assume this
288 decl has with no special effort. It is relevant only for FIELD_DECLs
289 and depends on the previous fields.
290 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
291 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
292 the record will be aligned to suit. */
295 layout_decl (tree decl
, unsigned int known_align
)
297 tree type
= TREE_TYPE (decl
);
298 enum tree_code code
= TREE_CODE (decl
);
301 if (code
== CONST_DECL
)
304 gcc_assert (code
== VAR_DECL
|| code
== PARM_DECL
|| code
== RESULT_DECL
305 || code
== TYPE_DECL
||code
== FIELD_DECL
);
307 rtl
= DECL_RTL_IF_SET (decl
);
309 if (type
== error_mark_node
)
310 type
= void_type_node
;
312 /* Usually the size and mode come from the data type without change,
313 however, the front-end may set the explicit width of the field, so its
314 size may not be the same as the size of its type. This happens with
315 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
316 also happens with other fields. For example, the C++ front-end creates
317 zero-sized fields corresponding to empty base classes, and depends on
318 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
319 size in bytes from the size in bits. If we have already set the mode,
320 don't set it again since we can be called twice for FIELD_DECLs. */
322 DECL_UNSIGNED (decl
) = TYPE_UNSIGNED (type
);
323 if (DECL_MODE (decl
) == VOIDmode
)
324 DECL_MODE (decl
) = TYPE_MODE (type
);
326 if (DECL_SIZE (decl
) == 0)
328 DECL_SIZE (decl
) = TYPE_SIZE (type
);
329 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
331 else if (DECL_SIZE_UNIT (decl
) == 0)
332 DECL_SIZE_UNIT (decl
)
333 = convert (sizetype
, size_binop (CEIL_DIV_EXPR
, DECL_SIZE (decl
),
336 if (code
!= FIELD_DECL
)
337 /* For non-fields, update the alignment from the type. */
338 do_type_align (type
, decl
);
340 /* For fields, it's a bit more complicated... */
342 bool old_user_align
= DECL_USER_ALIGN (decl
);
344 if (DECL_BIT_FIELD (decl
))
346 DECL_BIT_FIELD_TYPE (decl
) = type
;
348 /* A zero-length bit-field affects the alignment of the next
350 if (integer_zerop (DECL_SIZE (decl
))
351 && ! DECL_PACKED (decl
)
352 && ! targetm
.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl
)))
354 #ifdef PCC_BITFIELD_TYPE_MATTERS
355 if (PCC_BITFIELD_TYPE_MATTERS
)
356 do_type_align (type
, decl
);
360 #ifdef EMPTY_FIELD_BOUNDARY
361 if (EMPTY_FIELD_BOUNDARY
> DECL_ALIGN (decl
))
363 DECL_ALIGN (decl
) = EMPTY_FIELD_BOUNDARY
;
364 DECL_USER_ALIGN (decl
) = 0;
370 /* See if we can use an ordinary integer mode for a bit-field.
371 Conditions are: a fixed size that is correct for another mode
372 and occupying a complete byte or bytes on proper boundary. */
373 if (TYPE_SIZE (type
) != 0
374 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
375 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
)
377 enum machine_mode xmode
378 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
382 || known_align
>= GET_MODE_ALIGNMENT (xmode
)))
384 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
386 DECL_MODE (decl
) = xmode
;
387 DECL_BIT_FIELD (decl
) = 0;
391 /* Turn off DECL_BIT_FIELD if we won't need it set. */
392 if (TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
393 && known_align
>= TYPE_ALIGN (type
)
394 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
))
395 DECL_BIT_FIELD (decl
) = 0;
397 else if (DECL_PACKED (decl
) && DECL_USER_ALIGN (decl
))
398 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
399 round up; we'll reduce it again below. We want packing to
400 supersede USER_ALIGN inherited from the type, but defer to
401 alignment explicitly specified on the field decl. */;
403 do_type_align (type
, decl
);
405 /* If the field is of variable size, we can't misalign it since we
406 have no way to make a temporary to align the result. But this
407 isn't an issue if the decl is not addressable. Likewise if it
410 Note that do_type_align may set DECL_USER_ALIGN, so we need to
411 check old_user_align instead. */
412 if (DECL_PACKED (decl
)
414 && (DECL_NONADDRESSABLE_P (decl
)
415 || DECL_SIZE_UNIT (decl
) == 0
416 || TREE_CODE (DECL_SIZE_UNIT (decl
)) == INTEGER_CST
))
417 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
419 if (! DECL_USER_ALIGN (decl
) && ! DECL_PACKED (decl
))
421 /* Some targets (i.e. i386, VMS) limit struct field alignment
422 to a lower boundary than alignment of variables unless
423 it was overridden by attribute aligned. */
424 #ifdef BIGGEST_FIELD_ALIGNMENT
426 = MIN (DECL_ALIGN (decl
), (unsigned) BIGGEST_FIELD_ALIGNMENT
);
428 #ifdef ADJUST_FIELD_ALIGN
429 DECL_ALIGN (decl
) = ADJUST_FIELD_ALIGN (decl
, DECL_ALIGN (decl
));
433 /* Should this be controlled by DECL_USER_ALIGN, too? */
434 if (maximum_field_alignment
!= 0)
435 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), maximum_field_alignment
);
438 /* Evaluate nonconstant size only once, either now or as soon as safe. */
439 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
440 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
441 if (DECL_SIZE_UNIT (decl
) != 0
442 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
443 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
445 /* If requested, warn about definitions of large data objects. */
447 && (code
== VAR_DECL
|| code
== PARM_DECL
)
448 && ! DECL_EXTERNAL (decl
))
450 tree size
= DECL_SIZE_UNIT (decl
);
452 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
453 && compare_tree_int (size
, larger_than_size
) > 0)
455 int size_as_int
= TREE_INT_CST_LOW (size
);
457 if (compare_tree_int (size
, size_as_int
) == 0)
458 warning ("%Jsize of '%D' is %d bytes", decl
, decl
, size_as_int
);
460 warning ("%Jsize of '%D' is larger than %d bytes",
461 decl
, decl
, larger_than_size
);
465 /* If the RTL was already set, update its mode and mem attributes. */
468 PUT_MODE (rtl
, DECL_MODE (decl
));
469 SET_DECL_RTL (decl
, 0);
470 set_mem_attributes (rtl
, decl
, 1);
471 SET_DECL_RTL (decl
, rtl
);
475 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
476 a previous call to layout_decl and calls it again. */
479 relayout_decl (tree decl
)
481 DECL_SIZE (decl
) = DECL_SIZE_UNIT (decl
) = 0;
482 DECL_MODE (decl
) = VOIDmode
;
483 DECL_ALIGN (decl
) = 0;
484 SET_DECL_RTL (decl
, 0);
486 layout_decl (decl
, 0);
489 /* Hook for a front-end function that can modify the record layout as needed
490 immediately before it is finalized. */
492 void (*lang_adjust_rli
) (record_layout_info
) = 0;
495 set_lang_adjust_rli (void (*f
) (record_layout_info
))
500 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
501 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
502 is to be passed to all other layout functions for this record. It is the
503 responsibility of the caller to call `free' for the storage returned.
504 Note that garbage collection is not permitted until we finish laying
508 start_record_layout (tree t
)
510 record_layout_info rli
= xmalloc (sizeof (struct record_layout_info_s
));
514 /* If the type has a minimum specified alignment (via an attribute
515 declaration, for example) use it -- otherwise, start with a
516 one-byte alignment. */
517 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
518 rli
->unpacked_align
= rli
->record_align
;
519 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
521 #ifdef STRUCTURE_SIZE_BOUNDARY
522 /* Packed structures don't need to have minimum size. */
523 if (! TYPE_PACKED (t
))
524 rli
->record_align
= MAX (rli
->record_align
, (unsigned) STRUCTURE_SIZE_BOUNDARY
);
527 rli
->offset
= size_zero_node
;
528 rli
->bitpos
= bitsize_zero_node
;
530 rli
->pending_statics
= 0;
531 rli
->packed_maybe_necessary
= 0;
536 /* These four routines perform computations that convert between
537 the offset/bitpos forms and byte and bit offsets. */
540 bit_from_pos (tree offset
, tree bitpos
)
542 return size_binop (PLUS_EXPR
, bitpos
,
543 size_binop (MULT_EXPR
, convert (bitsizetype
, offset
),
548 byte_from_pos (tree offset
, tree bitpos
)
550 return size_binop (PLUS_EXPR
, offset
,
552 size_binop (TRUNC_DIV_EXPR
, bitpos
,
553 bitsize_unit_node
)));
557 pos_from_bit (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
,
560 *poffset
= size_binop (MULT_EXPR
,
562 size_binop (FLOOR_DIV_EXPR
, pos
,
563 bitsize_int (off_align
))),
564 size_int (off_align
/ BITS_PER_UNIT
));
565 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
568 /* Given a pointer to bit and byte offsets and an offset alignment,
569 normalize the offsets so they are within the alignment. */
572 normalize_offset (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
)
574 /* If the bit position is now larger than it should be, adjust it
576 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
578 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
579 bitsize_int (off_align
));
582 = size_binop (PLUS_EXPR
, *poffset
,
583 size_binop (MULT_EXPR
, convert (sizetype
, extra_aligns
),
584 size_int (off_align
/ BITS_PER_UNIT
)));
587 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
591 /* Print debugging information about the information in RLI. */
594 debug_rli (record_layout_info rli
)
596 print_node_brief (stderr
, "type", rli
->t
, 0);
597 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
598 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
600 fprintf (stderr
, "\naligns: rec = %u, unpack = %u, off = %u\n",
601 rli
->record_align
, rli
->unpacked_align
,
603 if (rli
->packed_maybe_necessary
)
604 fprintf (stderr
, "packed may be necessary\n");
606 if (rli
->pending_statics
)
608 fprintf (stderr
, "pending statics:\n");
609 debug_tree (rli
->pending_statics
);
613 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
614 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
617 normalize_rli (record_layout_info rli
)
619 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
622 /* Returns the size in bytes allocated so far. */
625 rli_size_unit_so_far (record_layout_info rli
)
627 return byte_from_pos (rli
->offset
, rli
->bitpos
);
630 /* Returns the size in bits allocated so far. */
633 rli_size_so_far (record_layout_info rli
)
635 return bit_from_pos (rli
->offset
, rli
->bitpos
);
638 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
639 the next available location is given by KNOWN_ALIGN. Update the
640 variable alignment fields in RLI, and return the alignment to give
644 update_alignment_for_field (record_layout_info rli
, tree field
,
645 unsigned int known_align
)
647 /* The alignment required for FIELD. */
648 unsigned int desired_align
;
649 /* The type of this field. */
650 tree type
= TREE_TYPE (field
);
651 /* True if the field was explicitly aligned by the user. */
655 /* Lay out the field so we know what alignment it needs. */
656 layout_decl (field
, known_align
);
657 desired_align
= DECL_ALIGN (field
);
658 user_align
= DECL_USER_ALIGN (field
);
660 is_bitfield
= (type
!= error_mark_node
661 && DECL_BIT_FIELD_TYPE (field
)
662 && ! integer_zerop (TYPE_SIZE (type
)));
664 /* Record must have at least as much alignment as any field.
665 Otherwise, the alignment of the field within the record is
667 if (is_bitfield
&& targetm
.ms_bitfield_layout_p (rli
->t
))
669 /* Here, the alignment of the underlying type of a bitfield can
670 affect the alignment of a record; even a zero-sized field
671 can do this. The alignment should be to the alignment of
672 the type, except that for zero-size bitfields this only
673 applies if there was an immediately prior, nonzero-size
674 bitfield. (That's the way it is, experimentally.) */
675 if (! integer_zerop (DECL_SIZE (field
))
676 ? ! DECL_PACKED (field
)
678 && DECL_BIT_FIELD_TYPE (rli
->prev_field
)
679 && ! integer_zerop (DECL_SIZE (rli
->prev_field
))))
681 unsigned int type_align
= TYPE_ALIGN (type
);
682 type_align
= MAX (type_align
, desired_align
);
683 if (maximum_field_alignment
!= 0)
684 type_align
= MIN (type_align
, maximum_field_alignment
);
685 rli
->record_align
= MAX (rli
->record_align
, type_align
);
686 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
689 #ifdef PCC_BITFIELD_TYPE_MATTERS
690 else if (is_bitfield
&& PCC_BITFIELD_TYPE_MATTERS
)
692 /* Named bit-fields cause the entire structure to have the
693 alignment implied by their type. Some targets also apply the same
694 rules to unnamed bitfields. */
695 if (DECL_NAME (field
) != 0
696 || targetm
.align_anon_bitfield ())
698 unsigned int type_align
= TYPE_ALIGN (type
);
700 #ifdef ADJUST_FIELD_ALIGN
701 if (! TYPE_USER_ALIGN (type
))
702 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
705 if (maximum_field_alignment
!= 0)
706 type_align
= MIN (type_align
, maximum_field_alignment
);
707 else if (DECL_PACKED (field
))
708 type_align
= MIN (type_align
, BITS_PER_UNIT
);
710 /* The alignment of the record is increased to the maximum
711 of the current alignment, the alignment indicated on the
712 field (i.e., the alignment specified by an __aligned__
713 attribute), and the alignment indicated by the type of
715 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
716 rli
->record_align
= MAX (rli
->record_align
, type_align
);
719 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
720 user_align
|= TYPE_USER_ALIGN (type
);
726 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
727 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
730 TYPE_USER_ALIGN (rli
->t
) |= user_align
;
732 return desired_align
;
735 /* Called from place_field to handle unions. */
738 place_union_field (record_layout_info rli
, tree field
)
740 update_alignment_for_field (rli
, field
, /*known_align=*/0);
742 DECL_FIELD_OFFSET (field
) = size_zero_node
;
743 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
744 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
746 /* We assume the union's size will be a multiple of a byte so we don't
747 bother with BITPOS. */
748 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
749 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
750 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
751 rli
->offset
= fold (build3 (COND_EXPR
, sizetype
,
752 DECL_QUALIFIER (field
),
753 DECL_SIZE_UNIT (field
), rli
->offset
));
756 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
757 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
758 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
759 units of alignment than the underlying TYPE. */
761 excess_unit_span (HOST_WIDE_INT byte_offset
, HOST_WIDE_INT bit_offset
,
762 HOST_WIDE_INT size
, HOST_WIDE_INT align
, tree type
)
764 /* Note that the calculation of OFFSET might overflow; we calculate it so
765 that we still get the right result as long as ALIGN is a power of two. */
766 unsigned HOST_WIDE_INT offset
= byte_offset
* BITS_PER_UNIT
+ bit_offset
;
768 offset
= offset
% align
;
769 return ((offset
+ size
+ align
- 1) / align
770 > ((unsigned HOST_WIDE_INT
) tree_low_cst (TYPE_SIZE (type
), 1)
775 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
776 is a FIELD_DECL to be added after those fields already present in
777 T. (FIELD is not actually added to the TYPE_FIELDS list here;
778 callers that desire that behavior must manually perform that step.) */
781 place_field (record_layout_info rli
, tree field
)
783 /* The alignment required for FIELD. */
784 unsigned int desired_align
;
785 /* The alignment FIELD would have if we just dropped it into the
786 record as it presently stands. */
787 unsigned int known_align
;
788 unsigned int actual_align
;
789 /* The type of this field. */
790 tree type
= TREE_TYPE (field
);
792 if (TREE_CODE (field
) == ERROR_MARK
|| TREE_CODE (type
) == ERROR_MARK
)
795 /* If FIELD is static, then treat it like a separate variable, not
796 really like a structure field. If it is a FUNCTION_DECL, it's a
797 method. In both cases, all we do is lay out the decl, and we do
798 it *after* the record is laid out. */
799 if (TREE_CODE (field
) == VAR_DECL
)
801 rli
->pending_statics
= tree_cons (NULL_TREE
, field
,
802 rli
->pending_statics
);
806 /* Enumerators and enum types which are local to this class need not
807 be laid out. Likewise for initialized constant fields. */
808 else if (TREE_CODE (field
) != FIELD_DECL
)
811 /* Unions are laid out very differently than records, so split
812 that code off to another function. */
813 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
815 place_union_field (rli
, field
);
819 /* Work out the known alignment so far. Note that A & (-A) is the
820 value of the least-significant bit in A that is one. */
821 if (! integer_zerop (rli
->bitpos
))
822 known_align
= (tree_low_cst (rli
->bitpos
, 1)
823 & - tree_low_cst (rli
->bitpos
, 1));
824 else if (integer_zerop (rli
->offset
))
825 known_align
= BIGGEST_ALIGNMENT
;
826 else if (host_integerp (rli
->offset
, 1))
827 known_align
= (BITS_PER_UNIT
828 * (tree_low_cst (rli
->offset
, 1)
829 & - tree_low_cst (rli
->offset
, 1)));
831 known_align
= rli
->offset_align
;
833 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
835 if (warn_packed
&& DECL_PACKED (field
))
837 if (known_align
>= TYPE_ALIGN (type
))
839 if (TYPE_ALIGN (type
) > desired_align
)
841 if (STRICT_ALIGNMENT
)
842 warning ("%Jpacked attribute causes inefficient alignment "
843 "for '%D'", field
, field
);
845 warning ("%Jpacked attribute is unnecessary for '%D'",
850 rli
->packed_maybe_necessary
= 1;
853 /* Does this field automatically have alignment it needs by virtue
854 of the fields that precede it and the record's own alignment? */
855 if (known_align
< desired_align
)
857 /* No, we need to skip space before this field.
858 Bump the cumulative size to multiple of field alignment. */
861 warning ("%Jpadding struct to align '%D'", field
, field
);
863 /* If the alignment is still within offset_align, just align
865 if (desired_align
< rli
->offset_align
)
866 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
869 /* First adjust OFFSET by the partial bits, then align. */
871 = size_binop (PLUS_EXPR
, rli
->offset
,
873 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
874 bitsize_unit_node
)));
875 rli
->bitpos
= bitsize_zero_node
;
877 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
880 if (! TREE_CONSTANT (rli
->offset
))
881 rli
->offset_align
= desired_align
;
885 /* Handle compatibility with PCC. Note that if the record has any
886 variable-sized fields, we need not worry about compatibility. */
887 #ifdef PCC_BITFIELD_TYPE_MATTERS
888 if (PCC_BITFIELD_TYPE_MATTERS
889 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
890 && TREE_CODE (field
) == FIELD_DECL
891 && type
!= error_mark_node
892 && DECL_BIT_FIELD (field
)
893 && ! DECL_PACKED (field
)
894 && maximum_field_alignment
== 0
895 && ! integer_zerop (DECL_SIZE (field
))
896 && host_integerp (DECL_SIZE (field
), 1)
897 && host_integerp (rli
->offset
, 1)
898 && host_integerp (TYPE_SIZE (type
), 1))
900 unsigned int type_align
= TYPE_ALIGN (type
);
901 tree dsize
= DECL_SIZE (field
);
902 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
903 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
904 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
906 #ifdef ADJUST_FIELD_ALIGN
907 if (! TYPE_USER_ALIGN (type
))
908 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
911 /* A bit field may not span more units of alignment of its type
912 than its type itself. Advance to next boundary if necessary. */
913 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
914 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
916 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
920 #ifdef BITFIELD_NBYTES_LIMITED
921 if (BITFIELD_NBYTES_LIMITED
922 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
923 && TREE_CODE (field
) == FIELD_DECL
924 && type
!= error_mark_node
925 && DECL_BIT_FIELD_TYPE (field
)
926 && ! DECL_PACKED (field
)
927 && ! integer_zerop (DECL_SIZE (field
))
928 && host_integerp (DECL_SIZE (field
), 1)
929 && host_integerp (rli
->offset
, 1)
930 && host_integerp (TYPE_SIZE (type
), 1))
932 unsigned int type_align
= TYPE_ALIGN (type
);
933 tree dsize
= DECL_SIZE (field
);
934 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
935 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
936 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
938 #ifdef ADJUST_FIELD_ALIGN
939 if (! TYPE_USER_ALIGN (type
))
940 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
943 if (maximum_field_alignment
!= 0)
944 type_align
= MIN (type_align
, maximum_field_alignment
);
945 /* ??? This test is opposite the test in the containing if
946 statement, so this code is unreachable currently. */
947 else if (DECL_PACKED (field
))
948 type_align
= MIN (type_align
, BITS_PER_UNIT
);
950 /* A bit field may not span the unit of alignment of its type.
951 Advance to next boundary if necessary. */
952 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
953 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
955 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
959 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
961 When a bit field is inserted into a packed record, the whole
962 size of the underlying type is used by one or more same-size
963 adjacent bitfields. (That is, if its long:3, 32 bits is
964 used in the record, and any additional adjacent long bitfields are
965 packed into the same chunk of 32 bits. However, if the size
966 changes, a new field of that size is allocated.) In an unpacked
967 record, this is the same as using alignment, but not equivalent
970 Note: for compatibility, we use the type size, not the type alignment
971 to determine alignment, since that matches the documentation */
973 if (targetm
.ms_bitfield_layout_p (rli
->t
)
974 && ((DECL_BIT_FIELD_TYPE (field
) && ! DECL_PACKED (field
))
975 || (rli
->prev_field
&& ! DECL_PACKED (rli
->prev_field
))))
977 /* At this point, either the prior or current are bitfields,
978 (possibly both), and we're dealing with MS packing. */
979 tree prev_saved
= rli
->prev_field
;
981 /* Is the prior field a bitfield? If so, handle "runs" of same
983 if (rli
->prev_field
/* necessarily a bitfield if it exists. */)
985 /* If both are bitfields, nonzero, and the same size, this is
986 the middle of a run. Zero declared size fields are special
987 and handled as "end of run". (Note: it's nonzero declared
988 size, but equal type sizes!) (Since we know that both
989 the current and previous fields are bitfields by the
990 time we check it, DECL_SIZE must be present for both.) */
991 if (DECL_BIT_FIELD_TYPE (field
)
992 && !integer_zerop (DECL_SIZE (field
))
993 && !integer_zerop (DECL_SIZE (rli
->prev_field
))
994 && host_integerp (DECL_SIZE (rli
->prev_field
), 0)
995 && host_integerp (TYPE_SIZE (type
), 0)
996 && simple_cst_equal (TYPE_SIZE (type
),
997 TYPE_SIZE (TREE_TYPE (rli
->prev_field
))))
999 /* We're in the middle of a run of equal type size fields; make
1000 sure we realign if we run out of bits. (Not decl size,
1002 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 0);
1004 if (rli
->remaining_in_alignment
< bitsize
)
1006 /* out of bits; bump up to next 'word'. */
1007 rli
->offset
= DECL_FIELD_OFFSET (rli
->prev_field
);
1009 = size_binop (PLUS_EXPR
, TYPE_SIZE (type
),
1010 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1011 rli
->prev_field
= field
;
1012 rli
->remaining_in_alignment
1013 = tree_low_cst (TYPE_SIZE (type
), 0);
1016 rli
->remaining_in_alignment
-= bitsize
;
1020 /* End of a run: if leaving a run of bitfields of the same type
1021 size, we have to "use up" the rest of the bits of the type
1024 Compute the new position as the sum of the size for the prior
1025 type and where we first started working on that type.
1026 Note: since the beginning of the field was aligned then
1027 of course the end will be too. No round needed. */
1029 if (!integer_zerop (DECL_SIZE (rli
->prev_field
)))
1031 tree type_size
= TYPE_SIZE (TREE_TYPE (rli
->prev_field
));
1034 = size_binop (PLUS_EXPR
, type_size
,
1035 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1038 /* We "use up" size zero fields; the code below should behave
1039 as if the prior field was not a bitfield. */
1042 /* Cause a new bitfield to be captured, either this time (if
1043 currently a bitfield) or next time we see one. */
1044 if (!DECL_BIT_FIELD_TYPE(field
)
1045 || integer_zerop (DECL_SIZE (field
)))
1046 rli
->prev_field
= NULL
;
1049 normalize_rli (rli
);
1052 /* If we're starting a new run of same size type bitfields
1053 (or a run of non-bitfields), set up the "first of the run"
1056 That is, if the current field is not a bitfield, or if there
1057 was a prior bitfield the type sizes differ, or if there wasn't
1058 a prior bitfield the size of the current field is nonzero.
1060 Note: we must be sure to test ONLY the type size if there was
1061 a prior bitfield and ONLY for the current field being zero if
1064 if (!DECL_BIT_FIELD_TYPE (field
)
1065 || ( prev_saved
!= NULL
1066 ? !simple_cst_equal (TYPE_SIZE (type
),
1067 TYPE_SIZE (TREE_TYPE (prev_saved
)))
1068 : !integer_zerop (DECL_SIZE (field
)) ))
1070 /* Never smaller than a byte for compatibility. */
1071 unsigned int type_align
= BITS_PER_UNIT
;
1073 /* (When not a bitfield), we could be seeing a flex array (with
1074 no DECL_SIZE). Since we won't be using remaining_in_alignment
1075 until we see a bitfield (and come by here again) we just skip
1077 if (DECL_SIZE (field
) != NULL
1078 && host_integerp (TYPE_SIZE (TREE_TYPE (field
)), 0)
1079 && host_integerp (DECL_SIZE (field
), 0))
1080 rli
->remaining_in_alignment
1081 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field
)), 0)
1082 - tree_low_cst (DECL_SIZE (field
), 0);
1084 /* Now align (conventionally) for the new type. */
1085 if (!DECL_PACKED(field
))
1086 type_align
= MAX(TYPE_ALIGN (type
), type_align
);
1089 && DECL_BIT_FIELD_TYPE (prev_saved
)
1090 /* If the previous bit-field is zero-sized, we've already
1091 accounted for its alignment needs (or ignored it, if
1092 appropriate) while placing it. */
1093 && ! integer_zerop (DECL_SIZE (prev_saved
)))
1094 type_align
= MAX (type_align
,
1095 TYPE_ALIGN (TREE_TYPE (prev_saved
)));
1097 if (maximum_field_alignment
!= 0)
1098 type_align
= MIN (type_align
, maximum_field_alignment
);
1100 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1102 /* If we really aligned, don't allow subsequent bitfields
1104 rli
->prev_field
= NULL
;
1108 /* Offset so far becomes the position of this field after normalizing. */
1109 normalize_rli (rli
);
1110 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1111 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1112 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1114 /* If this field ended up more aligned than we thought it would be (we
1115 approximate this by seeing if its position changed), lay out the field
1116 again; perhaps we can use an integral mode for it now. */
1117 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
1118 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
1119 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
1120 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
1121 actual_align
= BIGGEST_ALIGNMENT
;
1122 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
1123 actual_align
= (BITS_PER_UNIT
1124 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
1125 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
1127 actual_align
= DECL_OFFSET_ALIGN (field
);
1129 if (known_align
!= actual_align
)
1130 layout_decl (field
, actual_align
);
1132 /* Only the MS bitfields use this. */
1133 if (rli
->prev_field
== NULL
&& DECL_BIT_FIELD_TYPE(field
))
1134 rli
->prev_field
= field
;
1136 /* Now add size of this field to the size of the record. If the size is
1137 not constant, treat the field as being a multiple of bytes and just
1138 adjust the offset, resetting the bit position. Otherwise, apportion the
1139 size amongst the bit position and offset. First handle the case of an
1140 unspecified size, which can happen when we have an invalid nested struct
1141 definition, such as struct j { struct j { int i; } }. The error message
1142 is printed in finish_struct. */
1143 if (DECL_SIZE (field
) == 0)
1145 else if (TREE_CODE (DECL_SIZE_UNIT (field
)) != INTEGER_CST
1146 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field
)))
1149 = size_binop (PLUS_EXPR
, rli
->offset
,
1151 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1152 bitsize_unit_node
)));
1154 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1155 rli
->bitpos
= bitsize_zero_node
;
1156 rli
->offset_align
= MIN (rli
->offset_align
, desired_align
);
1160 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1161 normalize_rli (rli
);
1165 /* Assuming that all the fields have been laid out, this function uses
1166 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1167 indicated by RLI. */
1170 finalize_record_size (record_layout_info rli
)
1172 tree unpadded_size
, unpadded_size_unit
;
1174 /* Now we want just byte and bit offsets, so set the offset alignment
1175 to be a byte and then normalize. */
1176 rli
->offset_align
= BITS_PER_UNIT
;
1177 normalize_rli (rli
);
1179 /* Determine the desired alignment. */
1180 #ifdef ROUND_TYPE_ALIGN
1181 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
1184 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
1187 /* Compute the size so far. Be sure to allow for extra bits in the
1188 size in bytes. We have guaranteed above that it will be no more
1189 than a single byte. */
1190 unpadded_size
= rli_size_so_far (rli
);
1191 unpadded_size_unit
= rli_size_unit_so_far (rli
);
1192 if (! integer_zerop (rli
->bitpos
))
1194 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
1196 /* Round the size up to be a multiple of the required alignment. */
1197 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
1198 TYPE_SIZE_UNIT (rli
->t
)
1199 = round_up (unpadded_size_unit
, TYPE_ALIGN_UNIT (rli
->t
));
1201 if (warn_padded
&& TREE_CONSTANT (unpadded_size
)
1202 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0)
1203 warning ("padding struct size to alignment boundary");
1205 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
1206 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
1207 && TREE_CONSTANT (unpadded_size
))
1211 #ifdef ROUND_TYPE_ALIGN
1213 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1215 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1218 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
1219 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
1221 TYPE_PACKED (rli
->t
) = 0;
1223 if (TYPE_NAME (rli
->t
))
1227 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1228 name
= IDENTIFIER_POINTER (TYPE_NAME (rli
->t
));
1230 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli
->t
)));
1232 if (STRICT_ALIGNMENT
)
1233 warning ("packed attribute causes inefficient alignment for `%s'", name
);
1235 warning ("packed attribute is unnecessary for `%s'", name
);
1239 if (STRICT_ALIGNMENT
)
1240 warning ("packed attribute causes inefficient alignment");
1242 warning ("packed attribute is unnecessary");
1248 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1251 compute_record_mode (tree type
)
1254 enum machine_mode mode
= VOIDmode
;
1256 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1257 However, if possible, we use a mode that fits in a register
1258 instead, in order to allow for better optimization down the
1260 TYPE_MODE (type
) = BLKmode
;
1262 if (! host_integerp (TYPE_SIZE (type
), 1))
1265 /* A record which has any BLKmode members must itself be
1266 BLKmode; it can't go in a register. Unless the member is
1267 BLKmode only because it isn't aligned. */
1268 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1270 if (TREE_CODE (field
) != FIELD_DECL
)
1273 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1274 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1275 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
))
1276 && !(TYPE_SIZE (TREE_TYPE (field
)) != 0
1277 && integer_zerop (TYPE_SIZE (TREE_TYPE (field
)))))
1278 || ! host_integerp (bit_position (field
), 1)
1279 || DECL_SIZE (field
) == 0
1280 || ! host_integerp (DECL_SIZE (field
), 1))
1283 /* If this field is the whole struct, remember its mode so
1284 that, say, we can put a double in a class into a DF
1285 register instead of forcing it to live in the stack. */
1286 if (simple_cst_equal (TYPE_SIZE (type
), DECL_SIZE (field
)))
1287 mode
= DECL_MODE (field
);
1289 #ifdef MEMBER_TYPE_FORCES_BLK
1290 /* With some targets, eg. c4x, it is sub-optimal
1291 to access an aligned BLKmode structure as a scalar. */
1293 if (MEMBER_TYPE_FORCES_BLK (field
, mode
))
1295 #endif /* MEMBER_TYPE_FORCES_BLK */
1298 /* If we only have one real field; use its mode. This only applies to
1299 RECORD_TYPE. This does not apply to unions. */
1300 if (TREE_CODE (type
) == RECORD_TYPE
&& mode
!= VOIDmode
)
1301 TYPE_MODE (type
) = mode
;
1303 TYPE_MODE (type
) = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1305 /* If structure's known alignment is less than what the scalar
1306 mode would need, and it matters, then stick with BLKmode. */
1307 if (TYPE_MODE (type
) != BLKmode
1309 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1310 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1312 /* If this is the only reason this type is BLKmode, then
1313 don't force containing types to be BLKmode. */
1314 TYPE_NO_FORCE_BLK (type
) = 1;
1315 TYPE_MODE (type
) = BLKmode
;
1319 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1323 finalize_type_size (tree type
)
1325 /* Normally, use the alignment corresponding to the mode chosen.
1326 However, where strict alignment is not required, avoid
1327 over-aligning structures, since most compilers do not do this
1330 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1331 && (STRICT_ALIGNMENT
1332 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1333 && TREE_CODE (type
) != QUAL_UNION_TYPE
1334 && TREE_CODE (type
) != ARRAY_TYPE
)))
1336 TYPE_ALIGN (type
) = GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1337 TYPE_USER_ALIGN (type
) = 0;
1340 /* Do machine-dependent extra alignment. */
1341 #ifdef ROUND_TYPE_ALIGN
1343 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1346 /* If we failed to find a simple way to calculate the unit size
1347 of the type, find it by division. */
1348 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1349 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1350 result will fit in sizetype. We will get more efficient code using
1351 sizetype, so we force a conversion. */
1352 TYPE_SIZE_UNIT (type
)
1353 = convert (sizetype
,
1354 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1355 bitsize_unit_node
));
1357 if (TYPE_SIZE (type
) != 0)
1359 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1360 TYPE_SIZE_UNIT (type
) = round_up (TYPE_SIZE_UNIT (type
),
1361 TYPE_ALIGN_UNIT (type
));
1364 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1365 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1366 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1367 if (TYPE_SIZE_UNIT (type
) != 0
1368 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1369 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1371 /* Also layout any other variants of the type. */
1372 if (TYPE_NEXT_VARIANT (type
)
1373 || type
!= TYPE_MAIN_VARIANT (type
))
1376 /* Record layout info of this variant. */
1377 tree size
= TYPE_SIZE (type
);
1378 tree size_unit
= TYPE_SIZE_UNIT (type
);
1379 unsigned int align
= TYPE_ALIGN (type
);
1380 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1381 enum machine_mode mode
= TYPE_MODE (type
);
1383 /* Copy it into all variants. */
1384 for (variant
= TYPE_MAIN_VARIANT (type
);
1386 variant
= TYPE_NEXT_VARIANT (variant
))
1388 TYPE_SIZE (variant
) = size
;
1389 TYPE_SIZE_UNIT (variant
) = size_unit
;
1390 TYPE_ALIGN (variant
) = align
;
1391 TYPE_USER_ALIGN (variant
) = user_align
;
1392 TYPE_MODE (variant
) = mode
;
1397 /* Do all of the work required to layout the type indicated by RLI,
1398 once the fields have been laid out. This function will call `free'
1399 for RLI, unless FREE_P is false. Passing a value other than false
1400 for FREE_P is bad practice; this option only exists to support the
1404 finish_record_layout (record_layout_info rli
, int free_p
)
1406 /* Compute the final size. */
1407 finalize_record_size (rli
);
1409 /* Compute the TYPE_MODE for the record. */
1410 compute_record_mode (rli
->t
);
1412 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1413 finalize_type_size (rli
->t
);
1415 /* Lay out any static members. This is done now because their type
1416 may use the record's type. */
1417 while (rli
->pending_statics
)
1419 layout_decl (TREE_VALUE (rli
->pending_statics
), 0);
1420 rli
->pending_statics
= TREE_CHAIN (rli
->pending_statics
);
1429 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1430 NAME, its fields are chained in reverse on FIELDS.
1432 If ALIGN_TYPE is non-null, it is given the same alignment as
1436 finish_builtin_struct (tree type
, const char *name
, tree fields
,
1441 for (tail
= NULL_TREE
; fields
; tail
= fields
, fields
= next
)
1443 DECL_FIELD_CONTEXT (fields
) = type
;
1444 next
= TREE_CHAIN (fields
);
1445 TREE_CHAIN (fields
) = tail
;
1447 TYPE_FIELDS (type
) = tail
;
1451 TYPE_ALIGN (type
) = TYPE_ALIGN (align_type
);
1452 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (align_type
);
1456 #if 0 /* not yet, should get fixed properly later */
1457 TYPE_NAME (type
) = make_type_decl (get_identifier (name
), type
);
1459 TYPE_NAME (type
) = build_decl (TYPE_DECL
, get_identifier (name
), type
);
1461 TYPE_STUB_DECL (type
) = TYPE_NAME (type
);
1462 layout_decl (TYPE_NAME (type
), 0);
1465 /* Calculate the mode, size, and alignment for TYPE.
1466 For an array type, calculate the element separation as well.
1467 Record TYPE on the chain of permanent or temporary types
1468 so that dbxout will find out about it.
1470 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1471 layout_type does nothing on such a type.
1473 If the type is incomplete, its TYPE_SIZE remains zero. */
1476 layout_type (tree type
)
1480 if (type
== error_mark_node
)
1483 /* Do nothing if type has been laid out before. */
1484 if (TYPE_SIZE (type
))
1487 switch (TREE_CODE (type
))
1490 /* This kind of type is the responsibility
1491 of the language-specific code. */
1494 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1495 if (TYPE_PRECISION (type
) == 0)
1496 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1498 /* ... fall through ... */
1503 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1504 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1505 TYPE_UNSIGNED (type
) = 1;
1507 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
1509 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1510 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1514 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
1515 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1516 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1520 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1522 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1523 (TREE_CODE (TREE_TYPE (type
)) == REAL_TYPE
1524 ? MODE_COMPLEX_FLOAT
: MODE_COMPLEX_INT
),
1526 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1527 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1532 int nunits
= TYPE_VECTOR_SUBPARTS (type
);
1533 tree nunits_tree
= build_int_cst (NULL_TREE
, nunits
);
1534 tree innertype
= TREE_TYPE (type
);
1536 gcc_assert (!(nunits
& (nunits
- 1)));
1538 /* Find an appropriate mode for the vector type. */
1539 if (TYPE_MODE (type
) == VOIDmode
)
1541 enum machine_mode innermode
= TYPE_MODE (innertype
);
1542 enum machine_mode mode
;
1544 /* First, look for a supported vector type. */
1545 if (GET_MODE_CLASS (innermode
) == MODE_FLOAT
)
1546 mode
= MIN_MODE_VECTOR_FLOAT
;
1548 mode
= MIN_MODE_VECTOR_INT
;
1550 for (; mode
!= VOIDmode
; mode
= GET_MODE_WIDER_MODE (mode
))
1551 if (GET_MODE_NUNITS (mode
) == nunits
1552 && GET_MODE_INNER (mode
) == innermode
1553 && targetm
.vector_mode_supported_p (mode
))
1556 /* For integers, try mapping it to a same-sized scalar mode. */
1557 if (mode
== VOIDmode
1558 && GET_MODE_CLASS (innermode
) == MODE_INT
)
1559 mode
= mode_for_size (nunits
* GET_MODE_BITSIZE (innermode
),
1562 if (mode
== VOIDmode
|| !have_regs_of_mode
[mode
])
1563 TYPE_MODE (type
) = BLKmode
;
1565 TYPE_MODE (type
) = mode
;
1568 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1569 TYPE_SIZE_UNIT (type
) = int_const_binop (MULT_EXPR
,
1570 TYPE_SIZE_UNIT (innertype
),
1572 TYPE_SIZE (type
) = int_const_binop (MULT_EXPR
, TYPE_SIZE (innertype
),
1578 /* This is an incomplete type and so doesn't have a size. */
1579 TYPE_ALIGN (type
) = 1;
1580 TYPE_USER_ALIGN (type
) = 0;
1581 TYPE_MODE (type
) = VOIDmode
;
1585 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1586 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1587 /* A pointer might be MODE_PARTIAL_INT,
1588 but ptrdiff_t must be integral. */
1589 TYPE_MODE (type
) = mode_for_size (POINTER_SIZE
, MODE_INT
, 0);
1594 /* It's hard to see what the mode and size of a function ought to
1595 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1596 make it consistent with that. */
1597 TYPE_MODE (type
) = mode_for_size (FUNCTION_BOUNDARY
, MODE_INT
, 0);
1598 TYPE_SIZE (type
) = bitsize_int (FUNCTION_BOUNDARY
);
1599 TYPE_SIZE_UNIT (type
) = size_int (FUNCTION_BOUNDARY
/ BITS_PER_UNIT
);
1603 case REFERENCE_TYPE
:
1606 enum machine_mode mode
= ((TREE_CODE (type
) == REFERENCE_TYPE
1607 && reference_types_internal
)
1608 ? Pmode
: TYPE_MODE (type
));
1610 int nbits
= GET_MODE_BITSIZE (mode
);
1612 TYPE_SIZE (type
) = bitsize_int (nbits
);
1613 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (mode
));
1614 TYPE_UNSIGNED (type
) = 1;
1615 TYPE_PRECISION (type
) = nbits
;
1621 tree index
= TYPE_DOMAIN (type
);
1622 tree element
= TREE_TYPE (type
);
1624 build_pointer_type (element
);
1626 /* We need to know both bounds in order to compute the size. */
1627 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1628 && TYPE_SIZE (element
))
1630 tree ub
= TYPE_MAX_VALUE (index
);
1631 tree lb
= TYPE_MIN_VALUE (index
);
1635 /* The initial subtraction should happen in the original type so
1636 that (possible) negative values are handled appropriately. */
1637 length
= size_binop (PLUS_EXPR
, size_one_node
,
1639 fold (build2 (MINUS_EXPR
,
1643 /* Special handling for arrays of bits (for Chill). */
1644 element_size
= TYPE_SIZE (element
);
1645 if (TYPE_PACKED (type
) && INTEGRAL_TYPE_P (element
)
1646 && (integer_zerop (TYPE_MAX_VALUE (element
))
1647 || integer_onep (TYPE_MAX_VALUE (element
)))
1648 && host_integerp (TYPE_MIN_VALUE (element
), 1))
1650 HOST_WIDE_INT maxvalue
1651 = tree_low_cst (TYPE_MAX_VALUE (element
), 1);
1652 HOST_WIDE_INT minvalue
1653 = tree_low_cst (TYPE_MIN_VALUE (element
), 1);
1655 if (maxvalue
- minvalue
== 1
1656 && (maxvalue
== 1 || maxvalue
== 0))
1657 element_size
= integer_one_node
;
1660 /* If neither bound is a constant and sizetype is signed, make
1661 sure the size is never negative. We should really do this
1662 if *either* bound is non-constant, but this is the best
1663 compromise between C and Ada. */
1664 if (!TYPE_UNSIGNED (sizetype
)
1665 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
1666 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
1667 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
1669 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1670 convert (bitsizetype
, length
));
1672 /* If we know the size of the element, calculate the total
1673 size directly, rather than do some division thing below.
1674 This optimization helps Fortran assumed-size arrays
1675 (where the size of the array is determined at runtime)
1677 Note that we can't do this in the case where the size of
1678 the elements is one bit since TYPE_SIZE_UNIT cannot be
1679 set correctly in that case. */
1680 if (TYPE_SIZE_UNIT (element
) != 0 && ! integer_onep (element_size
))
1681 TYPE_SIZE_UNIT (type
)
1682 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1685 /* Now round the alignment and size,
1686 using machine-dependent criteria if any. */
1688 #ifdef ROUND_TYPE_ALIGN
1690 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1692 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1694 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (element
);
1695 TYPE_MODE (type
) = BLKmode
;
1696 if (TYPE_SIZE (type
) != 0
1697 #ifdef MEMBER_TYPE_FORCES_BLK
1698 && ! MEMBER_TYPE_FORCES_BLK (type
, VOIDmode
)
1700 /* BLKmode elements force BLKmode aggregate;
1701 else extract/store fields may lose. */
1702 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
1703 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
1705 /* One-element arrays get the component type's mode. */
1706 if (simple_cst_equal (TYPE_SIZE (type
),
1707 TYPE_SIZE (TREE_TYPE (type
))))
1708 TYPE_MODE (type
) = TYPE_MODE (TREE_TYPE (type
));
1711 = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1713 if (TYPE_MODE (type
) != BLKmode
1714 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
1715 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
))
1716 && TYPE_MODE (type
) != BLKmode
)
1718 TYPE_NO_FORCE_BLK (type
) = 1;
1719 TYPE_MODE (type
) = BLKmode
;
1727 case QUAL_UNION_TYPE
:
1730 record_layout_info rli
;
1732 /* Initialize the layout information. */
1733 rli
= start_record_layout (type
);
1735 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1736 in the reverse order in building the COND_EXPR that denotes
1737 its size. We reverse them again later. */
1738 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1739 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1741 /* Place all the fields. */
1742 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1743 place_field (rli
, field
);
1745 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1746 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1748 if (lang_adjust_rli
)
1749 (*lang_adjust_rli
) (rli
);
1751 /* Finish laying out the record. */
1752 finish_record_layout (rli
, /*free_p=*/true);
1756 case SET_TYPE
: /* Used by Chill and Pascal. */
1758 unsigned int alignment
;
1759 HOST_WIDE_INT size_in_bits
;
1760 HOST_WIDE_INT rounded_size
;
1762 gcc_assert (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type
)))
1764 gcc_assert (TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type
)))
1767 #ifndef SET_WORD_SIZE
1768 #define SET_WORD_SIZE BITS_PER_WORD
1770 alignment
= set_alignment
? set_alignment
: SET_WORD_SIZE
;
1772 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type
)), 0)
1773 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type
)), 0) + 1);
1775 = ((size_in_bits
+ alignment
- 1) / alignment
) * alignment
;
1777 if (rounded_size
> (int) alignment
)
1778 TYPE_MODE (type
) = BLKmode
;
1780 TYPE_MODE (type
) = mode_for_size (alignment
, MODE_INT
, 1);
1782 TYPE_SIZE (type
) = bitsize_int (rounded_size
);
1783 TYPE_SIZE_UNIT (type
) = size_int (rounded_size
/ BITS_PER_UNIT
);
1784 TYPE_ALIGN (type
) = alignment
;
1785 TYPE_USER_ALIGN (type
) = 0;
1786 TYPE_PRECISION (type
) = size_in_bits
;
1791 /* The size may vary in different languages, so the language front end
1792 should fill in the size. */
1793 TYPE_ALIGN (type
) = BIGGEST_ALIGNMENT
;
1794 TYPE_USER_ALIGN (type
) = 0;
1795 TYPE_MODE (type
) = BLKmode
;
1802 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1803 records and unions, finish_record_layout already called this
1805 if (TREE_CODE (type
) != RECORD_TYPE
1806 && TREE_CODE (type
) != UNION_TYPE
1807 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
1808 finalize_type_size (type
);
1810 /* If an alias set has been set for this aggregate when it was incomplete,
1811 force it into alias set 0.
1812 This is too conservative, but we cannot call record_component_aliases
1813 here because some frontends still change the aggregates after
1815 if (AGGREGATE_TYPE_P (type
) && TYPE_ALIAS_SET_KNOWN_P (type
))
1816 TYPE_ALIAS_SET (type
) = 0;
1819 /* Create and return a type for signed integers of PRECISION bits. */
1822 make_signed_type (int precision
)
1824 tree type
= make_node (INTEGER_TYPE
);
1826 TYPE_PRECISION (type
) = precision
;
1828 fixup_signed_type (type
);
1832 /* Create and return a type for unsigned integers of PRECISION bits. */
1835 make_unsigned_type (int precision
)
1837 tree type
= make_node (INTEGER_TYPE
);
1839 TYPE_PRECISION (type
) = precision
;
1841 fixup_unsigned_type (type
);
1845 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1846 value to enable integer types to be created. */
1849 initialize_sizetypes (bool signed_p
)
1851 tree t
= make_node (INTEGER_TYPE
);
1853 TYPE_MODE (t
) = SImode
;
1854 TYPE_ALIGN (t
) = GET_MODE_ALIGNMENT (SImode
);
1855 TYPE_USER_ALIGN (t
) = 0;
1856 TYPE_IS_SIZETYPE (t
) = 1;
1857 TYPE_UNSIGNED (t
) = !signed_p
;
1858 TYPE_SIZE (t
) = build_int_cst (t
, GET_MODE_BITSIZE (SImode
));
1859 TYPE_SIZE_UNIT (t
) = build_int_cst (t
, GET_MODE_SIZE (SImode
));
1860 TYPE_PRECISION (t
) = GET_MODE_BITSIZE (SImode
);
1861 TYPE_MIN_VALUE (t
) = build_int_cst (t
, 0);
1863 /* 1000 avoids problems with possible overflow and is certainly
1864 larger than any size value we'd want to be storing. */
1865 TYPE_MAX_VALUE (t
) = build_int_cst (t
, 1000);
1868 bitsizetype
= build_distinct_type_copy (t
);
1871 /* Make sizetype a version of TYPE, and initialize *sizetype
1872 accordingly. We do this by overwriting the stub sizetype and
1873 bitsizetype nodes created by initialize_sizetypes. This makes sure
1874 that (a) anything stubby about them no longer exists, (b) any
1875 INTEGER_CSTs created with such a type, remain valid. */
1878 set_sizetype (tree type
)
1880 int oprecision
= TYPE_PRECISION (type
);
1881 /* The *bitsizetype types use a precision that avoids overflows when
1882 calculating signed sizes / offsets in bits. However, when
1883 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1885 int precision
= MIN (oprecision
+ BITS_PER_UNIT_LOG
+ 1,
1886 2 * HOST_BITS_PER_WIDE_INT
);
1889 gcc_assert (TYPE_UNSIGNED (type
) == TYPE_UNSIGNED (sizetype
));
1891 t
= build_distinct_type_copy (type
);
1892 /* We do want to use sizetype's cache, as we will be replacing that
1894 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (sizetype
);
1895 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (sizetype
);
1896 TREE_TYPE (TYPE_CACHED_VALUES (t
)) = type
;
1897 TYPE_UID (t
) = TYPE_UID (sizetype
);
1898 TYPE_IS_SIZETYPE (t
) = 1;
1900 /* Replace our original stub sizetype. */
1901 memcpy (sizetype
, t
, tree_size (sizetype
));
1902 TYPE_MAIN_VARIANT (sizetype
) = sizetype
;
1904 t
= make_node (INTEGER_TYPE
);
1905 TYPE_NAME (t
) = get_identifier ("bit_size_type");
1906 /* We do want to use bitsizetype's cache, as we will be replacing that
1908 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (bitsizetype
);
1909 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (bitsizetype
);
1910 TYPE_PRECISION (t
) = precision
;
1911 TYPE_UID (t
) = TYPE_UID (bitsizetype
);
1912 TYPE_IS_SIZETYPE (t
) = 1;
1913 /* Replace our original stub bitsizetype. */
1914 memcpy (bitsizetype
, t
, tree_size (bitsizetype
));
1916 if (TYPE_UNSIGNED (type
))
1918 fixup_unsigned_type (bitsizetype
);
1919 ssizetype
= build_distinct_type_copy (make_signed_type (oprecision
));
1920 TYPE_IS_SIZETYPE (ssizetype
) = 1;
1921 sbitsizetype
= build_distinct_type_copy (make_signed_type (precision
));
1922 TYPE_IS_SIZETYPE (sbitsizetype
) = 1;
1926 fixup_signed_type (bitsizetype
);
1927 ssizetype
= sizetype
;
1928 sbitsizetype
= bitsizetype
;
1932 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1933 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1934 for TYPE, based on the PRECISION and whether or not the TYPE
1935 IS_UNSIGNED. PRECISION need not correspond to a width supported
1936 natively by the hardware; for example, on a machine with 8-bit,
1937 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1941 set_min_and_max_values_for_integral_type (tree type
,
1950 min_value
= build_int_cst (type
, 0);
1952 = build_int_cst_wide (type
, precision
- HOST_BITS_PER_WIDE_INT
>= 0
1954 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
1955 precision
- HOST_BITS_PER_WIDE_INT
> 0
1956 ? ((unsigned HOST_WIDE_INT
) ~0
1957 >> (HOST_BITS_PER_WIDE_INT
1958 - (precision
- HOST_BITS_PER_WIDE_INT
)))
1964 = build_int_cst_wide (type
,
1965 (precision
- HOST_BITS_PER_WIDE_INT
> 0
1967 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
1968 (((HOST_WIDE_INT
) (-1)
1969 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1970 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
1973 = build_int_cst_wide (type
,
1974 (precision
- HOST_BITS_PER_WIDE_INT
> 0
1976 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
1977 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1978 ? (((HOST_WIDE_INT
) 1
1979 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
1983 TYPE_MIN_VALUE (type
) = min_value
;
1984 TYPE_MAX_VALUE (type
) = max_value
;
1987 /* Set the extreme values of TYPE based on its precision in bits,
1988 then lay it out. Used when make_signed_type won't do
1989 because the tree code is not INTEGER_TYPE.
1990 E.g. for Pascal, when the -fsigned-char option is given. */
1993 fixup_signed_type (tree type
)
1995 int precision
= TYPE_PRECISION (type
);
1997 /* We can not represent properly constants greater then
1998 2 * HOST_BITS_PER_WIDE_INT, still we need the types
1999 as they are used by i386 vector extensions and friends. */
2000 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2001 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2003 set_min_and_max_values_for_integral_type (type
, precision
,
2004 /*is_unsigned=*/false);
2006 /* Lay out the type: set its alignment, size, etc. */
2010 /* Set the extreme values of TYPE based on its precision in bits,
2011 then lay it out. This is used both in `make_unsigned_type'
2012 and for enumeral types. */
2015 fixup_unsigned_type (tree type
)
2017 int precision
= TYPE_PRECISION (type
);
2019 /* We can not represent properly constants greater then
2020 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2021 as they are used by i386 vector extensions and friends. */
2022 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2023 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2025 TYPE_UNSIGNED (type
) = 1;
2027 set_min_and_max_values_for_integral_type (type
, precision
,
2028 /*is_unsigned=*/true);
2030 /* Lay out the type: set its alignment, size, etc. */
2034 /* Find the best machine mode to use when referencing a bit field of length
2035 BITSIZE bits starting at BITPOS.
2037 The underlying object is known to be aligned to a boundary of ALIGN bits.
2038 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2039 larger than LARGEST_MODE (usually SImode).
2041 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2042 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2043 mode meeting these conditions.
2045 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2046 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2047 all the conditions. */
2050 get_best_mode (int bitsize
, int bitpos
, unsigned int align
,
2051 enum machine_mode largest_mode
, int volatilep
)
2053 enum machine_mode mode
;
2054 unsigned int unit
= 0;
2056 /* Find the narrowest integer mode that contains the bit field. */
2057 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
2058 mode
= GET_MODE_WIDER_MODE (mode
))
2060 unit
= GET_MODE_BITSIZE (mode
);
2061 if ((bitpos
% unit
) + bitsize
<= unit
)
2065 if (mode
== VOIDmode
2066 /* It is tempting to omit the following line
2067 if STRICT_ALIGNMENT is true.
2068 But that is incorrect, since if the bitfield uses part of 3 bytes
2069 and we use a 4-byte mode, we could get a spurious segv
2070 if the extra 4th byte is past the end of memory.
2071 (Though at least one Unix compiler ignores this problem:
2072 that on the Sequent 386 machine. */
2073 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
2074 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
2077 if (SLOW_BYTE_ACCESS
&& ! volatilep
)
2079 enum machine_mode wide_mode
= VOIDmode
, tmode
;
2081 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
2082 tmode
= GET_MODE_WIDER_MODE (tmode
))
2084 unit
= GET_MODE_BITSIZE (tmode
);
2085 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
2086 && unit
<= BITS_PER_WORD
2087 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
2088 && (largest_mode
== VOIDmode
2089 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
2093 if (wide_mode
!= VOIDmode
)
2100 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2101 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2104 get_mode_bounds (enum machine_mode mode
, int sign
,
2105 enum machine_mode target_mode
,
2106 rtx
*mmin
, rtx
*mmax
)
2108 unsigned size
= GET_MODE_BITSIZE (mode
);
2109 unsigned HOST_WIDE_INT min_val
, max_val
;
2111 gcc_assert (size
<= HOST_BITS_PER_WIDE_INT
);
2115 min_val
= -((unsigned HOST_WIDE_INT
) 1 << (size
- 1));
2116 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1)) - 1;
2121 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1) << 1) - 1;
2124 *mmin
= GEN_INT (trunc_int_for_mode (min_val
, target_mode
));
2125 *mmax
= GEN_INT (trunc_int_for_mode (max_val
, target_mode
));
2128 #include "gt-stor-layout.h"