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 Free Software Foundation, Inc.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
34 /* Set to one when set_sizetype has been called. */
35 static int sizetype_set
;
37 /* List of types created before set_sizetype has been called. We do not
38 make this a GGC root since we want these nodes to be reclaimed. */
39 static tree early_type_list
;
41 /* Data type for the expressions representing sizes of data types.
42 It is the first integer type laid out. */
43 tree sizetype_tab
[(int) TYPE_KIND_LAST
];
45 /* If nonzero, this is an upper limit on alignment of structure fields.
46 The value is measured in bits. */
47 unsigned int maximum_field_alignment
;
49 /* If non-zero, the alignment of a bitstring or (power-)set value, in bits.
50 May be overridden by front-ends. */
51 unsigned int set_alignment
= 0;
53 static void finalize_record_size
PARAMS ((record_layout_info
));
54 static void finalize_type_size
PARAMS ((tree
));
55 static void place_union_field
PARAMS ((record_layout_info
, tree
));
56 extern void debug_rli
PARAMS ((record_layout_info
));
58 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
60 static tree pending_sizes
;
62 /* Nonzero means cannot safely call expand_expr now,
63 so put variable sizes onto `pending_sizes' instead. */
65 int immediate_size_expand
;
67 /* Get a list of all the objects put on the pending sizes list. */
72 tree chain
= pending_sizes
;
75 /* Put each SAVE_EXPR into the current function. */
76 for (t
= chain
; t
; t
= TREE_CHAIN (t
))
77 SAVE_EXPR_CONTEXT (TREE_VALUE (t
)) = current_function_decl
;
83 /* Put a chain of objects into the pending sizes list, which must be
87 put_pending_sizes (chain
)
93 pending_sizes
= chain
;
96 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
97 to serve as the actual size-expression for a type or decl. */
103 /* If the language-processor is to take responsibility for variable-sized
104 items (e.g., languages which have elaboration procedures like Ada),
105 just return SIZE unchanged. Likewise for self-referential sizes. */
106 if (TREE_CONSTANT (size
)
107 || global_bindings_p () < 0 || contains_placeholder_p (size
))
110 size
= save_expr (size
);
112 /* If an array with a variable number of elements is declared, and
113 the elements require destruction, we will emit a cleanup for the
114 array. That cleanup is run both on normal exit from the block
115 and in the exception-handler for the block. Normally, when code
116 is used in both ordinary code and in an exception handler it is
117 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
118 not wish to do that here; the array-size is the same in both
120 if (TREE_CODE (size
) == SAVE_EXPR
)
121 SAVE_EXPR_PERSISTENT_P (size
) = 1;
123 if (global_bindings_p ())
125 if (TREE_CONSTANT (size
))
126 error ("type size can't be explicitly evaluated");
128 error ("variable-size type declared outside of any function");
130 return size_one_node
;
133 if (immediate_size_expand
)
134 /* NULL_RTX is not defined; neither is the rtx type.
135 Also, we would like to pass const0_rtx here, but don't have it. */
136 expand_expr (size
, expand_expr (integer_zero_node
, NULL_PTR
, VOIDmode
, 0),
138 else if (cfun
!= 0 && cfun
->x_dont_save_pending_sizes_p
)
139 /* The front-end doesn't want us to keep a list of the expressions
140 that determine sizes for variable size objects. */
143 pending_sizes
= tree_cons (NULL_TREE
, size
, pending_sizes
);
148 #ifndef MAX_FIXED_MODE_SIZE
149 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
152 /* Return the machine mode to use for a nonscalar of SIZE bits.
153 The mode must be in class CLASS, and have exactly that many bits.
154 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
158 mode_for_size (size
, class, limit
)
160 enum mode_class
class;
163 register enum machine_mode mode
;
165 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
168 /* Get the first mode which has this size, in the specified class. */
169 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
170 mode
= GET_MODE_WIDER_MODE (mode
))
171 if (GET_MODE_BITSIZE (mode
) == size
)
177 /* Similar, except passed a tree node. */
180 mode_for_size_tree (size
, class, limit
)
182 enum mode_class
class;
185 if (TREE_CODE (size
) != INTEGER_CST
186 /* What we really want to say here is that the size can fit in a
187 host integer, but we know there's no way we'd find a mode for
188 this many bits, so there's no point in doing the precise test. */
189 || compare_tree_int (size
, 1000) > 0)
192 return mode_for_size (TREE_INT_CST_LOW (size
), class, limit
);
195 /* Similar, but never return BLKmode; return the narrowest mode that
196 contains at least the requested number of bits. */
199 smallest_mode_for_size (size
, class)
201 enum mode_class
class;
203 register enum machine_mode mode
;
205 /* Get the first mode which has at least this size, in the
207 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
208 mode
= GET_MODE_WIDER_MODE (mode
))
209 if (GET_MODE_BITSIZE (mode
) >= size
)
215 /* Find an integer mode of the exact same size, or BLKmode on failure. */
218 int_mode_for_mode (mode
)
219 enum machine_mode mode
;
221 switch (GET_MODE_CLASS (mode
))
224 case MODE_PARTIAL_INT
:
227 case MODE_COMPLEX_INT
:
228 case MODE_COMPLEX_FLOAT
:
230 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
237 /* ... fall through ... */
247 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
248 This can only be applied to objects of a sizetype. */
251 round_up (value
, divisor
)
255 tree arg
= size_int_type (divisor
, TREE_TYPE (value
));
257 return size_binop (MULT_EXPR
, size_binop (CEIL_DIV_EXPR
, value
, arg
), arg
);
260 /* Likewise, but round down. */
263 round_down (value
, divisor
)
267 tree arg
= size_int_type (divisor
, TREE_TYPE (value
));
269 return size_binop (MULT_EXPR
, size_binop (FLOOR_DIV_EXPR
, value
, arg
), arg
);
272 /* Set the size, mode and alignment of a ..._DECL node.
273 TYPE_DECL does need this for C++.
274 Note that LABEL_DECL and CONST_DECL nodes do not need this,
275 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
276 Don't call layout_decl for them.
278 KNOWN_ALIGN is the amount of alignment we can assume this
279 decl has with no special effort. It is relevant only for FIELD_DECLs
280 and depends on the previous fields.
281 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
282 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
283 the record will be aligned to suit. */
286 layout_decl (decl
, known_align
)
288 unsigned int known_align
;
290 register tree type
= TREE_TYPE (decl
);
291 register enum tree_code code
= TREE_CODE (decl
);
293 if (code
== CONST_DECL
)
295 else if (code
!= VAR_DECL
&& code
!= PARM_DECL
&& code
!= RESULT_DECL
296 && code
!= TYPE_DECL
&& code
!= FIELD_DECL
)
299 if (type
== error_mark_node
)
300 type
= void_type_node
;
302 /* Usually the size and mode come from the data type without change,
303 however, the front-end may set the explicit width of the field, so its
304 size may not be the same as the size of its type. This happens with
305 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
306 also happens with other fields. For example, the C++ front-end creates
307 zero-sized fields corresponding to empty base classes, and depends on
308 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
309 size in bytes from the size in bits. If we have already set the mode,
310 don't set it again since we can be called twice for FIELD_DECLs. */
312 TREE_UNSIGNED (decl
) = TREE_UNSIGNED (type
);
313 if (DECL_MODE (decl
) == VOIDmode
)
314 DECL_MODE (decl
) = TYPE_MODE (type
);
316 if (DECL_SIZE (decl
) == 0)
318 DECL_SIZE (decl
) = TYPE_SIZE (type
);
319 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
322 DECL_SIZE_UNIT (decl
)
323 = convert (sizetype
, size_binop (CEIL_DIV_EXPR
, DECL_SIZE (decl
),
326 /* Force alignment required for the data type.
327 But if the decl itself wants greater alignment, don't override that.
328 Likewise, if the decl is packed, don't override it. */
329 if (! (code
== FIELD_DECL
&& DECL_BIT_FIELD (decl
))
330 && (DECL_ALIGN (decl
) == 0
331 || (! (code
== FIELD_DECL
&& DECL_PACKED (decl
))
332 && TYPE_ALIGN (type
) > DECL_ALIGN (decl
))))
334 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
335 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
338 /* For fields, set the bit field type and update the alignment. */
339 if (code
== FIELD_DECL
)
341 DECL_BIT_FIELD_TYPE (decl
) = DECL_BIT_FIELD (decl
) ? type
: 0;
342 if (maximum_field_alignment
!= 0)
343 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), maximum_field_alignment
);
344 else if (DECL_PACKED (decl
))
346 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
347 DECL_USER_ALIGN (decl
) = 0;
351 /* See if we can use an ordinary integer mode for a bit-field.
352 Conditions are: a fixed size that is correct for another mode
353 and occupying a complete byte or bytes on proper boundary. */
354 if (code
== FIELD_DECL
&& DECL_BIT_FIELD (decl
)
355 && TYPE_SIZE (type
) != 0
356 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
357 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
)
359 register enum machine_mode xmode
360 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
362 if (xmode
!= BLKmode
&& known_align
>= GET_MODE_ALIGNMENT (xmode
))
364 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
366 DECL_MODE (decl
) = xmode
;
367 DECL_BIT_FIELD (decl
) = 0;
371 /* Turn off DECL_BIT_FIELD if we won't need it set. */
372 if (code
== FIELD_DECL
&& DECL_BIT_FIELD (decl
)
373 && TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
374 && known_align
>= TYPE_ALIGN (type
)
375 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
)
376 && DECL_SIZE_UNIT (decl
) != 0)
377 DECL_BIT_FIELD (decl
) = 0;
379 /* Evaluate nonconstant size only once, either now or as soon as safe. */
380 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
381 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
382 if (DECL_SIZE_UNIT (decl
) != 0
383 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
384 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
386 /* If requested, warn about definitions of large data objects. */
388 && (code
== VAR_DECL
|| code
== PARM_DECL
)
389 && ! DECL_EXTERNAL (decl
))
391 tree size
= DECL_SIZE_UNIT (decl
);
393 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
394 && compare_tree_int (size
, larger_than_size
) > 0)
396 unsigned int size_as_int
= TREE_INT_CST_LOW (size
);
398 if (compare_tree_int (size
, size_as_int
) == 0)
399 warning_with_decl (decl
, "size of `%s' is %d bytes", size_as_int
);
401 warning_with_decl (decl
, "size of `%s' is larger than %d bytes",
407 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
408 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
409 is to be passed to all other layout functions for this record. It is the
410 responsibility of the caller to call `free' for the storage returned.
411 Note that garbage collection is not permitted until we finish laying
415 start_record_layout (t
)
418 record_layout_info rli
419 = (record_layout_info
) xmalloc (sizeof (struct record_layout_info_s
));
423 /* If the type has a minimum specified alignment (via an attribute
424 declaration, for example) use it -- otherwise, start with a
425 one-byte alignment. */
426 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
427 rli
->unpacked_align
= rli
->record_align
;
428 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
430 #ifdef STRUCTURE_SIZE_BOUNDARY
431 /* Packed structures don't need to have minimum size. */
432 if (! TYPE_PACKED (t
))
433 rli
->record_align
= MAX (rli
->record_align
, STRUCTURE_SIZE_BOUNDARY
);
436 rli
->offset
= size_zero_node
;
437 rli
->bitpos
= bitsize_zero_node
;
438 rli
->pending_statics
= 0;
439 rli
->packed_maybe_necessary
= 0;
444 /* These four routines perform computations that convert between
445 the offset/bitpos forms and byte and bit offsets. */
448 bit_from_pos (offset
, bitpos
)
451 return size_binop (PLUS_EXPR
, bitpos
,
452 size_binop (MULT_EXPR
, convert (bitsizetype
, offset
),
457 byte_from_pos (offset
, bitpos
)
460 return size_binop (PLUS_EXPR
, offset
,
462 size_binop (TRUNC_DIV_EXPR
, bitpos
,
463 bitsize_unit_node
)));
467 pos_from_byte (poffset
, pbitpos
, off_align
, pos
)
468 tree
*poffset
, *pbitpos
;
469 unsigned int off_align
;
473 = size_binop (MULT_EXPR
,
475 size_binop (FLOOR_DIV_EXPR
, pos
,
476 bitsize_int (off_align
478 size_int (off_align
/ BITS_PER_UNIT
));
479 *pbitpos
= size_binop (MULT_EXPR
,
480 size_binop (FLOOR_MOD_EXPR
, pos
,
481 bitsize_int (off_align
/ BITS_PER_UNIT
)),
486 pos_from_bit (poffset
, pbitpos
, off_align
, pos
)
487 tree
*poffset
, *pbitpos
;
488 unsigned int off_align
;
491 *poffset
= size_binop (MULT_EXPR
,
493 size_binop (FLOOR_DIV_EXPR
, pos
,
494 bitsize_int (off_align
))),
495 size_int (off_align
/ BITS_PER_UNIT
));
496 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
499 /* Given a pointer to bit and byte offsets and an offset alignment,
500 normalize the offsets so they are within the alignment. */
503 normalize_offset (poffset
, pbitpos
, off_align
)
504 tree
*poffset
, *pbitpos
;
505 unsigned int off_align
;
507 /* If the bit position is now larger than it should be, adjust it
509 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
511 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
512 bitsize_int (off_align
));
515 = size_binop (PLUS_EXPR
, *poffset
,
516 size_binop (MULT_EXPR
, convert (sizetype
, extra_aligns
),
517 size_int (off_align
/ BITS_PER_UNIT
)));
520 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
524 /* Print debugging information about the information in RLI. */
528 record_layout_info rli
;
530 print_node_brief (stderr
, "type", rli
->t
, 0);
531 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
532 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
534 fprintf (stderr
, "\nrec_align = %u, unpack_align = %u, off_align = %u\n",
535 rli
->record_align
, rli
->unpacked_align
, rli
->offset_align
);
536 if (rli
->packed_maybe_necessary
)
537 fprintf (stderr
, "packed may be necessary\n");
539 if (rli
->pending_statics
)
541 fprintf (stderr
, "pending statics:\n");
542 debug_tree (rli
->pending_statics
);
546 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
547 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
551 record_layout_info rli
;
553 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
556 /* Returns the size in bytes allocated so far. */
559 rli_size_unit_so_far (rli
)
560 record_layout_info rli
;
562 return byte_from_pos (rli
->offset
, rli
->bitpos
);
565 /* Returns the size in bits allocated so far. */
568 rli_size_so_far (rli
)
569 record_layout_info rli
;
571 return bit_from_pos (rli
->offset
, rli
->bitpos
);
574 /* Called from place_field to handle unions. */
577 place_union_field (rli
, field
)
578 record_layout_info rli
;
581 unsigned int desired_align
;
583 layout_decl (field
, 0);
585 DECL_FIELD_OFFSET (field
) = size_zero_node
;
586 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
587 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
589 desired_align
= DECL_ALIGN (field
);
591 #ifdef BIGGEST_FIELD_ALIGNMENT
592 /* Some targets (i.e. i386) limit union field alignment
593 to a lower boundary than alignment of variables unless
594 it was overridden by attribute aligned. */
595 if (! DECL_USER_ALIGN (field
))
597 MIN (desired_align
, (unsigned) BIGGEST_FIELD_ALIGNMENT
);
600 /* Union must be at least as aligned as any field requires. */
601 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
603 #ifdef PCC_BITFIELD_TYPE_MATTERS
604 /* On the m88000, a bit field of declare type `int' forces the
605 entire union to have `int' alignment. */
606 if (PCC_BITFIELD_TYPE_MATTERS
&& DECL_BIT_FIELD_TYPE (field
))
607 rli
->record_align
= MAX (rli
->record_align
,
608 TYPE_ALIGN (TREE_TYPE (field
)));
611 /* We assume the union's size will be a multiple of a byte so we don't
612 bother with BITPOS. */
613 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
614 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
615 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
616 rli
->offset
= fold (build (COND_EXPR
, sizetype
,
617 DECL_QUALIFIER (field
),
618 DECL_SIZE_UNIT (field
), rli
->offset
));
621 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
622 is a FIELD_DECL to be added after those fields already present in
623 T. (FIELD is not actually added to the TYPE_FIELDS list here;
624 callers that desire that behavior must manually perform that step.) */
627 place_field (rli
, field
)
628 record_layout_info rli
;
631 /* The alignment required for FIELD. */
632 unsigned int desired_align
;
633 /* The alignment FIELD would have if we just dropped it into the
634 record as it presently stands. */
635 unsigned int known_align
;
636 unsigned int actual_align
;
637 unsigned int user_align
;
638 /* The type of this field. */
639 tree type
= TREE_TYPE (field
);
641 if (TREE_CODE (field
) == ERROR_MARK
|| TREE_CODE (type
) == ERROR_MARK
)
644 /* If FIELD is static, then treat it like a separate variable, not
645 really like a structure field. If it is a FUNCTION_DECL, it's a
646 method. In both cases, all we do is lay out the decl, and we do
647 it *after* the record is laid out. */
648 if (TREE_CODE (field
) == VAR_DECL
)
650 rli
->pending_statics
= tree_cons (NULL_TREE
, field
,
651 rli
->pending_statics
);
655 /* Enumerators and enum types which are local to this class need not
656 be laid out. Likewise for initialized constant fields. */
657 else if (TREE_CODE (field
) != FIELD_DECL
)
660 /* Unions are laid out very differently than records, so split
661 that code off to another function. */
662 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
664 place_union_field (rli
, field
);
668 /* Work out the known alignment so far. Note that A & (-A) is the
669 value of the least-significant bit in A that is one. */
670 if (! integer_zerop (rli
->bitpos
))
671 known_align
= (tree_low_cst (rli
->bitpos
, 1)
672 & - tree_low_cst (rli
->bitpos
, 1));
673 else if (integer_zerop (rli
->offset
))
674 known_align
= BIGGEST_ALIGNMENT
;
675 else if (host_integerp (rli
->offset
, 1))
676 known_align
= (BITS_PER_UNIT
677 * (tree_low_cst (rli
->offset
, 1)
678 & - tree_low_cst (rli
->offset
, 1)));
680 known_align
= rli
->offset_align
;
682 /* Lay out the field so we know what alignment it needs. For a
683 packed field, use the alignment as specified, disregarding what
684 the type would want. */
685 desired_align
= DECL_ALIGN (field
);
686 user_align
= DECL_USER_ALIGN (field
);
687 layout_decl (field
, known_align
);
688 if (! DECL_PACKED (field
))
690 desired_align
= DECL_ALIGN (field
);
691 user_align
= DECL_USER_ALIGN (field
);
694 #ifdef BIGGEST_FIELD_ALIGNMENT
695 /* Some targets (i.e. i386, VMS) limit struct field alignment
696 to a lower boundary than alignment of variables unless
697 it was overridden by attribute aligned. */
700 MIN (desired_align
, (unsigned) BIGGEST_FIELD_ALIGNMENT
);
702 #ifdef ADJUST_FIELD_ALIGN
703 desired_align
= ADJUST_FIELD_ALIGN (field
, desired_align
);
706 /* Record must have at least as much alignment as any field.
707 Otherwise, the alignment of the field within the record is
709 #ifdef PCC_BITFIELD_TYPE_MATTERS
710 if (PCC_BITFIELD_TYPE_MATTERS
&& type
!= error_mark_node
711 && DECL_BIT_FIELD_TYPE (field
)
712 && ! integer_zerop (TYPE_SIZE (type
)))
714 /* For these machines, a zero-length field does not
715 affect the alignment of the structure as a whole.
716 It does, however, affect the alignment of the next field
717 within the structure. */
718 if (! integer_zerop (DECL_SIZE (field
)))
719 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
720 else if (! DECL_PACKED (field
))
721 desired_align
= TYPE_ALIGN (type
);
723 /* A named bit field of declared type `int'
724 forces the entire structure to have `int' alignment. */
725 if (DECL_NAME (field
) != 0)
727 unsigned int type_align
= TYPE_ALIGN (type
);
729 if (maximum_field_alignment
!= 0)
730 type_align
= MIN (type_align
, maximum_field_alignment
);
731 else if (DECL_PACKED (field
))
732 type_align
= MIN (type_align
, BITS_PER_UNIT
);
734 rli
->record_align
= MAX (rli
->record_align
, type_align
);
736 rli
->unpacked_align
= MAX (rli
->unpacked_align
,
743 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
744 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
747 if (warn_packed
&& DECL_PACKED (field
))
749 if (known_align
> TYPE_ALIGN (type
))
751 if (TYPE_ALIGN (type
) > desired_align
)
753 if (STRICT_ALIGNMENT
)
754 warning_with_decl (field
, "packed attribute causes inefficient alignment for `%s'");
756 warning_with_decl (field
, "packed attribute is unnecessary for `%s'");
760 rli
->packed_maybe_necessary
= 1;
763 /* Does this field automatically have alignment it needs by virtue
764 of the fields that precede it and the record's own alignment? */
765 if (known_align
< desired_align
)
767 /* No, we need to skip space before this field.
768 Bump the cumulative size to multiple of field alignment. */
771 warning_with_decl (field
, "padding struct to align `%s'");
773 /* If the alignment is still within offset_align, just align
775 if (desired_align
< rli
->offset_align
)
776 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
779 /* First adjust OFFSET by the partial bits, then align. */
781 = size_binop (PLUS_EXPR
, rli
->offset
,
783 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
784 bitsize_unit_node
)));
785 rli
->bitpos
= bitsize_zero_node
;
787 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
790 if (! TREE_CONSTANT (rli
->offset
))
791 rli
->offset_align
= desired_align
;
795 /* Handle compatibility with PCC. Note that if the record has any
796 variable-sized fields, we need not worry about compatibility. */
797 #ifdef PCC_BITFIELD_TYPE_MATTERS
798 if (PCC_BITFIELD_TYPE_MATTERS
799 && TREE_CODE (field
) == FIELD_DECL
800 && type
!= error_mark_node
801 && DECL_BIT_FIELD (field
)
802 && ! DECL_PACKED (field
)
803 && maximum_field_alignment
== 0
804 && ! integer_zerop (DECL_SIZE (field
))
805 && host_integerp (DECL_SIZE (field
), 1)
806 && host_integerp (rli
->offset
, 1)
807 && host_integerp (TYPE_SIZE (type
), 1))
809 unsigned int type_align
= TYPE_ALIGN (type
);
810 tree dsize
= DECL_SIZE (field
);
811 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
812 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
813 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
815 /* A bit field may not span more units of alignment of its type
816 than its type itself. Advance to next boundary if necessary. */
817 if ((((offset
* BITS_PER_UNIT
+ bit_offset
+ field_size
+
820 - (offset
* BITS_PER_UNIT
+ bit_offset
) / type_align
)
821 > tree_low_cst (TYPE_SIZE (type
), 1) / type_align
)
822 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
826 #ifdef BITFIELD_NBYTES_LIMITED
827 if (BITFIELD_NBYTES_LIMITED
828 && TREE_CODE (field
) == FIELD_DECL
829 && type
!= error_mark_node
830 && DECL_BIT_FIELD_TYPE (field
)
831 && ! DECL_PACKED (field
)
832 && ! integer_zerop (DECL_SIZE (field
))
833 && host_integerp (DECL_SIZE (field
), 1)
834 && host_integerp (rli
->offset
, 1)
835 && host_integerp (TYPE_SIZE (type
), 1))
837 unsigned int type_align
= TYPE_ALIGN (type
);
838 tree dsize
= DECL_SIZE (field
);
839 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
840 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
841 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
843 if (maximum_field_alignment
!= 0)
844 type_align
= MIN (type_align
, maximum_field_alignment
);
845 /* ??? This test is opposite the test in the containing if
846 statement, so this code is unreachable currently. */
847 else if (DECL_PACKED (field
))
848 type_align
= MIN (type_align
, BITS_PER_UNIT
);
850 /* A bit field may not span the unit of alignment of its type.
851 Advance to next boundary if necessary. */
852 /* ??? This code should match the code above for the
853 PCC_BITFIELD_TYPE_MATTERS case. */
854 if ((offset
* BITS_PER_UNIT
+ bit_offset
) / type_align
855 != ((offset
* BITS_PER_UNIT
+ bit_offset
+ field_size
- 1)
857 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
861 /* Offset so far becomes the position of this field after normalizing. */
863 DECL_FIELD_OFFSET (field
) = rli
->offset
;
864 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
865 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
867 /* If this field ended up more aligned than we thought it would be (we
868 approximate this by seeing if its position changed), lay out the field
869 again; perhaps we can use an integral mode for it now. */
870 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
871 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
872 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
873 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
874 actual_align
= BIGGEST_ALIGNMENT
;
875 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
876 actual_align
= (BITS_PER_UNIT
877 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
878 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
880 actual_align
= DECL_OFFSET_ALIGN (field
);
882 if (known_align
!= actual_align
)
883 layout_decl (field
, actual_align
);
885 /* Now add size of this field to the size of the record. If the size is
886 not constant, treat the field as being a multiple of bytes and just
887 adjust the offset, resetting the bit position. Otherwise, apportion the
888 size amongst the bit position and offset. First handle the case of an
889 unspecified size, which can happen when we have an invalid nested struct
890 definition, such as struct j { struct j { int i; } }. The error message
891 is printed in finish_struct. */
892 if (DECL_SIZE (field
) == 0)
894 else if (! TREE_CONSTANT (DECL_SIZE_UNIT (field
)))
897 = size_binop (PLUS_EXPR
, rli
->offset
,
899 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
900 bitsize_unit_node
)));
902 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
903 rli
->bitpos
= bitsize_zero_node
;
904 rli
->offset_align
= MIN (rli
->offset_align
, DECL_ALIGN (field
));
908 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
913 /* Assuming that all the fields have been laid out, this function uses
914 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
915 inidicated by RLI. */
918 finalize_record_size (rli
)
919 record_layout_info rli
;
921 tree unpadded_size
, unpadded_size_unit
;
923 /* Now we want just byte and bit offsets, so set the offset alignment
924 to be a byte and then normalize. */
925 rli
->offset_align
= BITS_PER_UNIT
;
928 /* Determine the desired alignment. */
929 #ifdef ROUND_TYPE_ALIGN
930 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
933 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
935 TYPE_USER_ALIGN (rli
->t
) = 1;
937 /* Compute the size so far. Be sure to allow for extra bits in the
938 size in bytes. We have guaranteed above that it will be no more
939 than a single byte. */
940 unpadded_size
= rli_size_so_far (rli
);
941 unpadded_size_unit
= rli_size_unit_so_far (rli
);
942 if (! integer_zerop (rli
->bitpos
))
944 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
946 /* Record the un-rounded size in the binfo node. But first we check
947 the size of TYPE_BINFO to make sure that BINFO_SIZE is available. */
948 if (TYPE_BINFO (rli
->t
) && TREE_VEC_LENGTH (TYPE_BINFO (rli
->t
)) > 6)
950 TYPE_BINFO_SIZE (rli
->t
) = unpadded_size
;
951 TYPE_BINFO_SIZE_UNIT (rli
->t
) = unpadded_size_unit
;
954 /* Round the size up to be a multiple of the required alignment */
955 #ifdef ROUND_TYPE_SIZE
956 TYPE_SIZE (rli
->t
) = ROUND_TYPE_SIZE (rli
->t
, unpadded_size
,
957 TYPE_ALIGN (rli
->t
));
958 TYPE_SIZE_UNIT (rli
->t
)
959 = ROUND_TYPE_SIZE_UNIT (rli
->t
, unpadded_size_unit
,
960 TYPE_ALIGN (rli
->t
) / BITS_PER_UNIT
);
962 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
963 TYPE_SIZE_UNIT (rli
->t
) = round_up (unpadded_size_unit
,
964 TYPE_ALIGN (rli
->t
) / BITS_PER_UNIT
);
967 if (warn_padded
&& TREE_CONSTANT (unpadded_size
)
968 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0)
969 warning ("padding struct size to alignment boundary");
971 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
972 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
973 && TREE_CONSTANT (unpadded_size
))
977 #ifdef ROUND_TYPE_ALIGN
979 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
981 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
984 #ifdef ROUND_TYPE_SIZE
985 unpacked_size
= ROUND_TYPE_SIZE (rli
->t
, TYPE_SIZE (rli
->t
),
986 rli
->unpacked_align
);
988 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
991 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
993 TYPE_PACKED (rli
->t
) = 0;
995 if (TYPE_NAME (rli
->t
))
999 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1000 name
= IDENTIFIER_POINTER (TYPE_NAME (rli
->t
));
1002 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli
->t
)));
1004 if (STRICT_ALIGNMENT
)
1005 warning ("packed attribute causes inefficient alignment for `%s'", name
);
1007 warning ("packed attribute is unnecessary for `%s'", name
);
1011 if (STRICT_ALIGNMENT
)
1012 warning ("packed attribute causes inefficient alignment");
1014 warning ("packed attribute is unnecessary");
1020 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1023 compute_record_mode (type
)
1027 enum machine_mode mode
= VOIDmode
;
1029 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1030 However, if possible, we use a mode that fits in a register
1031 instead, in order to allow for better optimization down the
1033 TYPE_MODE (type
) = BLKmode
;
1035 if (! host_integerp (TYPE_SIZE (type
), 1))
1038 /* A record which has any BLKmode members must itself be
1039 BLKmode; it can't go in a register. Unless the member is
1040 BLKmode only because it isn't aligned. */
1041 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1043 unsigned HOST_WIDE_INT bitpos
;
1045 if (TREE_CODE (field
) != FIELD_DECL
)
1048 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1049 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1050 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
)))
1051 || ! host_integerp (bit_position (field
), 1)
1052 || ! host_integerp (DECL_SIZE (field
), 1))
1055 bitpos
= int_bit_position (field
);
1057 /* Must be BLKmode if any field crosses a word boundary,
1058 since extract_bit_field can't handle that in registers. */
1059 if (bitpos
/ BITS_PER_WORD
1060 != ((TREE_INT_CST_LOW (DECL_SIZE (field
)) + bitpos
- 1)
1062 /* But there is no problem if the field is entire words. */
1063 && tree_low_cst (DECL_SIZE (field
), 1) % BITS_PER_WORD
!= 0)
1066 /* If this field is the whole struct, remember its mode so
1067 that, say, we can put a double in a class into a DF
1068 register instead of forcing it to live in the stack. However,
1069 we don't support using such a mode if there is no integer mode
1070 of the same size, so don't set it here. */
1071 if (field
== TYPE_FIELDS (type
) && TREE_CHAIN (field
) == 0
1072 && int_mode_for_mode (DECL_MODE (field
)) != BLKmode
)
1073 mode
= DECL_MODE (field
);
1075 #ifdef STRUCT_FORCE_BLK
1076 /* With some targets, eg. c4x, it is sub-optimal
1077 to access an aligned BLKmode structure as a scalar. */
1078 if (mode
== VOIDmode
&& STRUCT_FORCE_BLK (field
))
1080 #endif /* STRUCT_FORCE_BLK */
1083 if (mode
!= VOIDmode
)
1084 /* We only have one real field; use its mode. */
1085 TYPE_MODE (type
) = mode
;
1087 TYPE_MODE (type
) = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1089 /* If structure's known alignment is less than what the scalar
1090 mode would need, and it matters, then stick with BLKmode. */
1091 if (TYPE_MODE (type
) != BLKmode
1093 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1094 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1096 /* If this is the only reason this type is BLKmode, then
1097 don't force containing types to be BLKmode. */
1098 TYPE_NO_FORCE_BLK (type
) = 1;
1099 TYPE_MODE (type
) = BLKmode
;
1103 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1107 finalize_type_size (type
)
1110 /* Normally, use the alignment corresponding to the mode chosen.
1111 However, where strict alignment is not required, avoid
1112 over-aligning structures, since most compilers do not do this
1115 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1116 && (STRICT_ALIGNMENT
1117 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1118 && TREE_CODE (type
) != QUAL_UNION_TYPE
1119 && TREE_CODE (type
) != ARRAY_TYPE
)))
1121 TYPE_ALIGN (type
) = GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1122 TYPE_USER_ALIGN (type
) = 0;
1125 /* Do machine-dependent extra alignment. */
1126 #ifdef ROUND_TYPE_ALIGN
1128 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1131 /* If we failed to find a simple way to calculate the unit size
1132 of the type, find it by division. */
1133 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1134 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1135 result will fit in sizetype. We will get more efficient code using
1136 sizetype, so we force a conversion. */
1137 TYPE_SIZE_UNIT (type
)
1138 = convert (sizetype
,
1139 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1140 bitsize_unit_node
));
1142 if (TYPE_SIZE (type
) != 0)
1144 #ifdef ROUND_TYPE_SIZE
1146 = ROUND_TYPE_SIZE (type
, TYPE_SIZE (type
), TYPE_ALIGN (type
));
1147 TYPE_SIZE_UNIT (type
)
1148 = ROUND_TYPE_SIZE_UNIT (type
, TYPE_SIZE_UNIT (type
),
1149 TYPE_ALIGN (type
) / BITS_PER_UNIT
);
1151 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1152 TYPE_SIZE_UNIT (type
)
1153 = round_up (TYPE_SIZE_UNIT (type
), TYPE_ALIGN (type
) / BITS_PER_UNIT
);
1157 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1158 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1159 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1160 if (TYPE_SIZE_UNIT (type
) != 0
1161 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1162 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1164 /* Also layout any other variants of the type. */
1165 if (TYPE_NEXT_VARIANT (type
)
1166 || type
!= TYPE_MAIN_VARIANT (type
))
1169 /* Record layout info of this variant. */
1170 tree size
= TYPE_SIZE (type
);
1171 tree size_unit
= TYPE_SIZE_UNIT (type
);
1172 unsigned int align
= TYPE_ALIGN (type
);
1173 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1174 enum machine_mode mode
= TYPE_MODE (type
);
1176 /* Copy it into all variants. */
1177 for (variant
= TYPE_MAIN_VARIANT (type
);
1179 variant
= TYPE_NEXT_VARIANT (variant
))
1181 TYPE_SIZE (variant
) = size
;
1182 TYPE_SIZE_UNIT (variant
) = size_unit
;
1183 TYPE_ALIGN (variant
) = align
;
1184 TYPE_USER_ALIGN (variant
) = user_align
;
1185 TYPE_MODE (variant
) = mode
;
1190 /* Do all of the work required to layout the type indicated by RLI,
1191 once the fields have been laid out. This function will call `free'
1195 finish_record_layout (rli
)
1196 record_layout_info rli
;
1198 /* Compute the final size. */
1199 finalize_record_size (rli
);
1201 /* Compute the TYPE_MODE for the record. */
1202 compute_record_mode (rli
->t
);
1204 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1205 finalize_type_size (rli
->t
);
1207 /* Lay out any static members. This is done now because their type
1208 may use the record's type. */
1209 while (rli
->pending_statics
)
1211 layout_decl (TREE_VALUE (rli
->pending_statics
), 0);
1212 rli
->pending_statics
= TREE_CHAIN (rli
->pending_statics
);
1219 /* Calculate the mode, size, and alignment for TYPE.
1220 For an array type, calculate the element separation as well.
1221 Record TYPE on the chain of permanent or temporary types
1222 so that dbxout will find out about it.
1224 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1225 layout_type does nothing on such a type.
1227 If the type is incomplete, its TYPE_SIZE remains zero. */
1238 /* Do nothing if type has been laid out before. */
1239 if (TYPE_SIZE (type
))
1242 /* Make sure all nodes we allocate are not momentary; they must last
1243 past the current statement. */
1244 old
= suspend_momentary ();
1246 /* Put all our nodes into the same obstack as the type. Also,
1247 make expressions saveable (this is a no-op for permanent types). */
1249 push_obstacks (TYPE_OBSTACK (type
), TYPE_OBSTACK (type
));
1250 saveable_allocation ();
1252 switch (TREE_CODE (type
))
1255 /* This kind of type is the responsibility
1256 of the language-specific code. */
1259 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1260 if (TYPE_PRECISION (type
) == 0)
1261 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1263 /* ... fall through ... */
1268 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1269 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1270 TREE_UNSIGNED (type
) = 1;
1272 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
1274 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1275 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1279 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
1280 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1281 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1285 TREE_UNSIGNED (type
) = TREE_UNSIGNED (TREE_TYPE (type
));
1287 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1288 (TREE_CODE (TREE_TYPE (type
)) == INTEGER_TYPE
1289 ? MODE_COMPLEX_INT
: MODE_COMPLEX_FLOAT
),
1291 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1292 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1299 subtype
= TREE_TYPE (type
);
1300 TREE_UNSIGNED (type
) = TREE_UNSIGNED (subtype
);
1301 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1302 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1307 /* This is an incomplete type and so doesn't have a size. */
1308 TYPE_ALIGN (type
) = 1;
1309 TYPE_USER_ALIGN (type
) = 0;
1310 TYPE_MODE (type
) = VOIDmode
;
1314 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1315 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1316 TYPE_MODE (type
) = ptr_mode
;
1321 TYPE_MODE (type
) = mode_for_size (2 * POINTER_SIZE
, MODE_INT
, 0);
1322 TYPE_SIZE (type
) = bitsize_int (2 * POINTER_SIZE
);
1323 TYPE_SIZE_UNIT (type
) = size_int ((2 * POINTER_SIZE
) / BITS_PER_UNIT
);
1327 case REFERENCE_TYPE
:
1328 TYPE_MODE (type
) = ptr_mode
;
1329 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1330 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1331 TREE_UNSIGNED (type
) = 1;
1332 TYPE_PRECISION (type
) = POINTER_SIZE
;
1337 register tree index
= TYPE_DOMAIN (type
);
1338 register tree element
= TREE_TYPE (type
);
1340 build_pointer_type (element
);
1342 /* We need to know both bounds in order to compute the size. */
1343 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1344 && TYPE_SIZE (element
))
1346 tree ub
= TYPE_MAX_VALUE (index
);
1347 tree lb
= TYPE_MIN_VALUE (index
);
1351 /* If UB is max (lb - 1, x), remove the MAX_EXPR since the
1352 test for negative below covers it. */
1353 if (TREE_CODE (ub
) == MAX_EXPR
1354 && TREE_CODE (TREE_OPERAND (ub
, 0)) == MINUS_EXPR
1355 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub
, 0), 1))
1356 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub
, 0), 0),
1358 ub
= TREE_OPERAND (ub
, 1);
1359 else if (TREE_CODE (ub
) == MAX_EXPR
1360 && TREE_CODE (TREE_OPERAND (ub
, 1)) == MINUS_EXPR
1361 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub
, 1), 1))
1362 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub
, 1),
1365 ub
= TREE_OPERAND (ub
, 0);
1367 /* The initial subtraction should happen in the original type so
1368 that (possible) negative values are handled appropriately. */
1369 length
= size_binop (PLUS_EXPR
, size_one_node
,
1371 fold (build (MINUS_EXPR
,
1375 /* If neither bound is a constant and sizetype is signed, make
1376 sure the size is never negative. We should really do this
1377 if *either* bound is non-constant, but this is the best
1378 compromise between C and Ada. */
1379 if (! TREE_UNSIGNED (sizetype
)
1380 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
1381 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
1382 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
1384 /* Special handling for arrays of bits (for Chill). */
1385 element_size
= TYPE_SIZE (element
);
1386 if (TYPE_PACKED (type
) && INTEGRAL_TYPE_P (element
))
1388 HOST_WIDE_INT maxvalue
1389 = TREE_INT_CST_LOW (TYPE_MAX_VALUE (element
));
1390 HOST_WIDE_INT minvalue
1391 = TREE_INT_CST_LOW (TYPE_MIN_VALUE (element
));
1393 if (maxvalue
- minvalue
== 1
1394 && (maxvalue
== 1 || maxvalue
== 0))
1395 element_size
= integer_one_node
;
1398 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1399 convert (bitsizetype
, length
));
1401 /* If we know the size of the element, calculate the total
1402 size directly, rather than do some division thing below.
1403 This optimization helps Fortran assumed-size arrays
1404 (where the size of the array is determined at runtime)
1406 Note that we can't do this in the case where the size of
1407 the elements is one bit since TYPE_SIZE_UNIT cannot be
1408 set correctly in that case. */
1409 if (TYPE_SIZE_UNIT (element
) != 0 && ! integer_onep (element_size
))
1410 TYPE_SIZE_UNIT (type
)
1411 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1414 /* Now round the alignment and size,
1415 using machine-dependent criteria if any. */
1417 #ifdef ROUND_TYPE_ALIGN
1419 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1421 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1424 #ifdef ROUND_TYPE_SIZE
1425 if (TYPE_SIZE (type
) != 0)
1428 = ROUND_TYPE_SIZE (type
, TYPE_SIZE (type
), TYPE_ALIGN (type
));
1430 /* If the rounding changed the size of the type, remove any
1431 pre-calculated TYPE_SIZE_UNIT. */
1432 if (simple_cst_equal (TYPE_SIZE (type
), tmp
) != 1)
1433 TYPE_SIZE_UNIT (type
) = NULL
;
1435 TYPE_SIZE (type
) = tmp
;
1439 TYPE_MODE (type
) = BLKmode
;
1440 if (TYPE_SIZE (type
) != 0
1441 /* BLKmode elements force BLKmode aggregate;
1442 else extract/store fields may lose. */
1443 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
1444 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
1447 = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1449 if (TYPE_MODE (type
) != BLKmode
1450 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
1451 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
))
1452 && TYPE_MODE (type
) != BLKmode
)
1454 TYPE_NO_FORCE_BLK (type
) = 1;
1455 TYPE_MODE (type
) = BLKmode
;
1463 case QUAL_UNION_TYPE
:
1466 record_layout_info rli
;
1468 /* Initialize the layout information. */
1469 rli
= start_record_layout (type
);
1471 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1472 in the reverse order in building the COND_EXPR that denotes
1473 its size. We reverse them again later. */
1474 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1475 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1477 /* Place all the fields. */
1478 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1479 place_field (rli
, field
);
1481 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1482 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1484 /* Finish laying out the record. */
1485 finish_record_layout (rli
);
1489 case SET_TYPE
: /* Used by Chill and Pascal. */
1490 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
1491 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
)
1495 #ifndef SET_WORD_SIZE
1496 #define SET_WORD_SIZE BITS_PER_WORD
1498 unsigned int alignment
1499 = set_alignment
? set_alignment
: SET_WORD_SIZE
;
1501 = (TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type
)))
1502 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type
))) + 1);
1504 = ((size_in_bits
+ alignment
- 1) / alignment
) * alignment
;
1506 if (rounded_size
> (int) alignment
)
1507 TYPE_MODE (type
) = BLKmode
;
1509 TYPE_MODE (type
) = mode_for_size (alignment
, MODE_INT
, 1);
1511 TYPE_SIZE (type
) = bitsize_int (rounded_size
);
1512 TYPE_SIZE_UNIT (type
) = size_int (rounded_size
/ BITS_PER_UNIT
);
1513 TYPE_ALIGN (type
) = alignment
;
1514 TYPE_USER_ALIGN (type
) = 0;
1515 TYPE_PRECISION (type
) = size_in_bits
;
1520 /* The size may vary in different languages, so the language front end
1521 should fill in the size. */
1522 TYPE_ALIGN (type
) = BIGGEST_ALIGNMENT
;
1523 TYPE_USER_ALIGN (type
) = 0;
1524 TYPE_MODE (type
) = BLKmode
;
1531 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1532 records and unions, finish_record_layout already called this
1534 if (TREE_CODE (type
) != RECORD_TYPE
1535 && TREE_CODE (type
) != UNION_TYPE
1536 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
1537 finalize_type_size (type
);
1540 resume_momentary (old
);
1542 /* If this type is created before sizetype has been permanently set,
1543 record it so set_sizetype can fix it up. */
1545 early_type_list
= tree_cons (NULL_TREE
, type
, early_type_list
);
1548 /* Create and return a type for signed integers of PRECISION bits. */
1551 make_signed_type (precision
)
1554 register tree type
= make_node (INTEGER_TYPE
);
1556 TYPE_PRECISION (type
) = precision
;
1558 fixup_signed_type (type
);
1562 /* Create and return a type for unsigned integers of PRECISION bits. */
1565 make_unsigned_type (precision
)
1568 register tree type
= make_node (INTEGER_TYPE
);
1570 TYPE_PRECISION (type
) = precision
;
1572 fixup_unsigned_type (type
);
1576 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1577 value to enable integer types to be created. */
1580 initialize_sizetypes ()
1582 tree t
= make_node (INTEGER_TYPE
);
1584 /* Set this so we do something reasonable for the build_int_2 calls
1586 integer_type_node
= t
;
1588 TYPE_MODE (t
) = SImode
;
1589 TYPE_ALIGN (t
) = GET_MODE_ALIGNMENT (SImode
);
1590 TYPE_USER_ALIGN (t
) = 0;
1591 TYPE_SIZE (t
) = build_int_2 (GET_MODE_BITSIZE (SImode
), 0);
1592 TYPE_SIZE_UNIT (t
) = build_int_2 (GET_MODE_SIZE (SImode
), 0);
1593 TREE_UNSIGNED (t
) = 1;
1594 TYPE_PRECISION (t
) = GET_MODE_BITSIZE (SImode
);
1595 TYPE_MIN_VALUE (t
) = build_int_2 (0, 0);
1596 TYPE_IS_SIZETYPE (t
) = 1;
1598 /* 1000 avoids problems with possible overflow and is certainly
1599 larger than any size value we'd want to be storing. */
1600 TYPE_MAX_VALUE (t
) = build_int_2 (1000, 0);
1602 /* These two must be different nodes because of the caching done in
1605 bitsizetype
= copy_node (t
);
1606 integer_type_node
= 0;
1609 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1610 Also update the type of any standard type's sizes made so far. */
1616 int oprecision
= TYPE_PRECISION (type
);
1617 /* The *bitsizetype types use a precision that avoids overflows when
1618 calculating signed sizes / offsets in bits. However, when
1619 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1621 int precision
= MIN (oprecision
+ BITS_PER_UNIT_LOG
+ 1,
1622 2 * HOST_BITS_PER_WIDE_INT
);
1629 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1630 sizetype
= copy_node (type
);
1631 TYPE_DOMAIN (sizetype
) = type
;
1632 TYPE_IS_SIZETYPE (sizetype
) = 1;
1633 bitsizetype
= make_node (INTEGER_TYPE
);
1634 TYPE_NAME (bitsizetype
) = TYPE_NAME (type
);
1635 TYPE_PRECISION (bitsizetype
) = precision
;
1636 TYPE_IS_SIZETYPE (bitsizetype
) = 1;
1638 if (TREE_UNSIGNED (type
))
1639 fixup_unsigned_type (bitsizetype
);
1641 fixup_signed_type (bitsizetype
);
1643 layout_type (bitsizetype
);
1645 if (TREE_UNSIGNED (type
))
1647 usizetype
= sizetype
;
1648 ubitsizetype
= bitsizetype
;
1649 ssizetype
= copy_node (make_signed_type (oprecision
));
1650 sbitsizetype
= copy_node (make_signed_type (precision
));
1654 ssizetype
= sizetype
;
1655 sbitsizetype
= bitsizetype
;
1656 usizetype
= copy_node (make_unsigned_type (oprecision
));
1657 ubitsizetype
= copy_node (make_unsigned_type (precision
));
1660 TYPE_NAME (bitsizetype
) = get_identifier ("bit_size_type");
1662 /* Show is a sizetype, is a main type, and has no pointers to it. */
1663 for (i
= 0; i
< ARRAY_SIZE (sizetype_tab
); i
++)
1665 TYPE_IS_SIZETYPE (sizetype_tab
[i
]) = 1;
1666 TYPE_MAIN_VARIANT (sizetype_tab
[i
]) = sizetype_tab
[i
];
1667 TYPE_NEXT_VARIANT (sizetype_tab
[i
]) = 0;
1668 TYPE_POINTER_TO (sizetype_tab
[i
]) = 0;
1669 TYPE_REFERENCE_TO (sizetype_tab
[i
]) = 0;
1672 ggc_add_tree_root ((tree
*) &sizetype_tab
,
1673 sizeof sizetype_tab
/ sizeof (tree
));
1675 /* Go down each of the types we already made and set the proper type
1676 for the sizes in them. */
1677 for (t
= early_type_list
; t
!= 0; t
= TREE_CHAIN (t
))
1679 if (TREE_CODE (TREE_VALUE (t
)) != INTEGER_TYPE
)
1682 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t
))) = bitsizetype
;
1683 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t
))) = sizetype
;
1686 early_type_list
= 0;
1690 /* Set the extreme values of TYPE based on its precision in bits,
1691 then lay it out. Used when make_signed_type won't do
1692 because the tree code is not INTEGER_TYPE.
1693 E.g. for Pascal, when the -fsigned-char option is given. */
1696 fixup_signed_type (type
)
1699 register int precision
= TYPE_PRECISION (type
);
1701 TYPE_MIN_VALUE (type
)
1702 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1703 ? 0 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
1704 (((HOST_WIDE_INT
) (-1)
1705 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1706 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
1708 TYPE_MAX_VALUE (type
)
1709 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1710 ? -1 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
1711 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1712 ? (((HOST_WIDE_INT
) 1
1713 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
1716 TREE_TYPE (TYPE_MIN_VALUE (type
)) = type
;
1717 TREE_TYPE (TYPE_MAX_VALUE (type
)) = type
;
1719 /* Lay out the type: set its alignment, size, etc. */
1723 /* Set the extreme values of TYPE based on its precision in bits,
1724 then lay it out. This is used both in `make_unsigned_type'
1725 and for enumeral types. */
1728 fixup_unsigned_type (type
)
1731 register int precision
= TYPE_PRECISION (type
);
1733 TYPE_MIN_VALUE (type
) = build_int_2 (0, 0);
1734 TYPE_MAX_VALUE (type
)
1735 = build_int_2 (precision
- HOST_BITS_PER_WIDE_INT
>= 0
1736 ? -1 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
1737 precision
- HOST_BITS_PER_WIDE_INT
> 0
1738 ? ((unsigned HOST_WIDE_INT
) ~0
1739 >> (HOST_BITS_PER_WIDE_INT
1740 - (precision
- HOST_BITS_PER_WIDE_INT
)))
1742 TREE_TYPE (TYPE_MIN_VALUE (type
)) = type
;
1743 TREE_TYPE (TYPE_MAX_VALUE (type
)) = type
;
1745 /* Lay out the type: set its alignment, size, etc. */
1749 /* Find the best machine mode to use when referencing a bit field of length
1750 BITSIZE bits starting at BITPOS.
1752 The underlying object is known to be aligned to a boundary of ALIGN bits.
1753 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1754 larger than LARGEST_MODE (usually SImode).
1756 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1757 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1758 mode meeting these conditions.
1760 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1761 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1762 all the conditions. */
1765 get_best_mode (bitsize
, bitpos
, align
, largest_mode
, volatilep
)
1766 int bitsize
, bitpos
;
1768 enum machine_mode largest_mode
;
1771 enum machine_mode mode
;
1772 unsigned int unit
= 0;
1774 /* Find the narrowest integer mode that contains the bit field. */
1775 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
1776 mode
= GET_MODE_WIDER_MODE (mode
))
1778 unit
= GET_MODE_BITSIZE (mode
);
1779 if ((bitpos
% unit
) + bitsize
<= unit
)
1783 if (mode
== VOIDmode
1784 /* It is tempting to omit the following line
1785 if STRICT_ALIGNMENT is true.
1786 But that is incorrect, since if the bitfield uses part of 3 bytes
1787 and we use a 4-byte mode, we could get a spurious segv
1788 if the extra 4th byte is past the end of memory.
1789 (Though at least one Unix compiler ignores this problem:
1790 that on the Sequent 386 machine. */
1791 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
1792 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
1795 if (SLOW_BYTE_ACCESS
&& ! volatilep
)
1797 enum machine_mode wide_mode
= VOIDmode
, tmode
;
1799 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
1800 tmode
= GET_MODE_WIDER_MODE (tmode
))
1802 unit
= GET_MODE_BITSIZE (tmode
);
1803 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
1804 && unit
<= BITS_PER_WORD
1805 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
1806 && (largest_mode
== VOIDmode
1807 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
1811 if (wide_mode
!= VOIDmode
)
1818 /* Return the alignment of MODE. This will be bounded by 1 and
1819 BIGGEST_ALIGNMENT. */
1822 get_mode_alignment (mode
)
1823 enum machine_mode mode
;
1825 unsigned int alignment
= GET_MODE_UNIT_SIZE (mode
) * BITS_PER_UNIT
;
1827 /* Extract the LSB of the size. */
1828 alignment
= alignment
& -alignment
;
1830 alignment
= MIN (BIGGEST_ALIGNMENT
, MAX (1, alignment
));
1834 /* This function is run once to initialize stor-layout.c. */
1837 init_stor_layout_once ()
1839 ggc_add_tree_root (&pending_sizes
, 1);