1 /* C-compiler utilities for types and variables storage layout
2 Copyright (C) 1987, 88, 92, 93, 94, 1995 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
29 #define CEIL(x,y) (((x) + (y) - 1) / (y))
31 /* Data type for the expressions representing sizes of data types.
32 It is the first integer type laid out.
37 /* An integer constant with value 0 whose type is sizetype. */
41 /* An integer constant with value 1 whose type is sizetype. */
45 /* If nonzero, this is an upper limit on alignment of structure fields.
46 The value is measured in bits. */
47 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 int set_alignment
= 0;
53 #define GET_MODE_ALIGNMENT(MODE) \
54 MIN (BIGGEST_ALIGNMENT, \
55 MAX (1, (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT)))
57 static enum machine_mode smallest_mode_for_size
PROTO((unsigned int,
59 static tree layout_record
PROTO((tree
));
60 static void layout_union
PROTO((tree
));
62 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
64 static tree pending_sizes
;
66 /* Nonzero means cannot safely call expand_expr now,
67 so put variable sizes onto `pending_sizes' instead. */
69 int immediate_size_expand
;
74 tree chain
= pending_sizes
;
77 /* Put each SAVE_EXPR into the current function. */
78 for (t
= chain
; t
; t
= TREE_CHAIN (t
))
79 SAVE_EXPR_CONTEXT (TREE_VALUE (t
)) = current_function_decl
;
85 put_pending_sizes (chain
)
91 pending_sizes
= chain
;
94 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
95 to serve as the actual size-expression for a type or decl. */
101 /* If the language-processor is to take responsibility for variable-sized
102 items (e.g., languages which have elaboration procedures like Ada),
103 just return SIZE unchanged. Likewise for self-referential sizes. */
104 if (TREE_CONSTANT (size
)
105 || global_bindings_p () < 0 || contains_placeholder_p (size
))
108 size
= save_expr (size
);
110 if (global_bindings_p ())
112 if (TREE_CONSTANT (size
))
113 error ("type size can't be explicitly evaluated");
115 error ("variable-size type declared outside of any function");
120 if (immediate_size_expand
)
121 /* NULL_RTX is not defined; neither is the rtx type.
122 Also, we would like to pass const0_rtx here, but don't have it. */
123 expand_expr (size
, expand_expr (integer_zero_node
, NULL_PTR
, VOIDmode
, 0),
126 pending_sizes
= tree_cons (NULL_TREE
, size
, pending_sizes
);
131 #ifndef MAX_FIXED_MODE_SIZE
132 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
135 /* Return the machine mode to use for a nonscalar of SIZE bits.
136 The mode must be in class CLASS, and have exactly that many bits.
137 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
141 mode_for_size (size
, class, limit
)
143 enum mode_class
class;
146 register enum machine_mode mode
;
148 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
151 /* Get the first mode which has this size, in the specified class. */
152 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
153 mode
= GET_MODE_WIDER_MODE (mode
))
154 if (GET_MODE_BITSIZE (mode
) == size
)
160 /* Similar, but never return BLKmode; return the narrowest mode that
161 contains at least the requested number of bits. */
163 static enum machine_mode
164 smallest_mode_for_size (size
, class)
166 enum mode_class
class;
168 register enum machine_mode mode
;
170 /* Get the first mode which has at least this size, in the
172 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
173 mode
= GET_MODE_WIDER_MODE (mode
))
174 if (GET_MODE_BITSIZE (mode
) >= size
)
180 /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
183 round_up (value
, divisor
)
187 return size_binop (MULT_EXPR
,
188 size_binop (CEIL_DIV_EXPR
, value
, size_int (divisor
)),
192 /* Set the size, mode and alignment of a ..._DECL node.
193 TYPE_DECL does need this for C++.
194 Note that LABEL_DECL and CONST_DECL nodes do not need this,
195 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
196 Don't call layout_decl for them.
198 KNOWN_ALIGN is the amount of alignment we can assume this
199 decl has with no special effort. It is relevant only for FIELD_DECLs
200 and depends on the previous fields.
201 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
202 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
203 the record will be aligned to suit. */
206 layout_decl (decl
, known_align
)
208 unsigned known_align
;
210 register tree type
= TREE_TYPE (decl
);
211 register enum tree_code code
= TREE_CODE (decl
);
212 int spec_size
= DECL_FIELD_SIZE (decl
);
214 if (code
== CONST_DECL
)
217 if (code
!= VAR_DECL
&& code
!= PARM_DECL
&& code
!= RESULT_DECL
218 && code
!= FIELD_DECL
&& code
!= TYPE_DECL
)
221 if (type
== error_mark_node
)
223 type
= void_type_node
;
227 /* Usually the size and mode come from the data type without change. */
229 DECL_MODE (decl
) = TYPE_MODE (type
);
230 TREE_UNSIGNED (decl
) = TREE_UNSIGNED (type
);
231 if (DECL_SIZE (decl
) == 0)
232 DECL_SIZE (decl
) = TYPE_SIZE (type
);
234 if (code
== FIELD_DECL
&& DECL_BIT_FIELD (decl
))
236 if (spec_size
== 0 && DECL_NAME (decl
) != 0)
239 /* Size is specified number of bits. */
240 DECL_SIZE (decl
) = size_int (spec_size
);
242 /* Force alignment required for the data type.
243 But if the decl itself wants greater alignment, don't override that.
244 Likewise, if the decl is packed, don't override it. */
245 else if (DECL_ALIGN (decl
) == 0
246 || (! DECL_PACKED (decl
) && TYPE_ALIGN (type
) > DECL_ALIGN (decl
)))
247 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
249 /* See if we can use an ordinary integer mode for a bit-field. */
250 /* Conditions are: a fixed size that is correct for another mode
251 and occupying a complete byte or bytes on proper boundary. */
252 if (code
== FIELD_DECL
)
254 DECL_BIT_FIELD_TYPE (decl
) = DECL_BIT_FIELD (decl
) ? type
: 0;
255 if (maximum_field_alignment
!= 0)
256 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), maximum_field_alignment
);
257 else if (flag_pack_struct
)
258 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
261 if (DECL_BIT_FIELD (decl
)
262 && TYPE_SIZE (type
) != 0
263 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
)
265 register enum machine_mode xmode
266 = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl
)), MODE_INT
, 1);
269 && known_align
% GET_MODE_ALIGNMENT (xmode
) == 0)
271 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
273 DECL_MODE (decl
) = xmode
;
274 DECL_SIZE (decl
) = size_int (GET_MODE_BITSIZE (xmode
));
275 /* This no longer needs to be accessed as a bit field. */
276 DECL_BIT_FIELD (decl
) = 0;
280 /* Evaluate nonconstant size only once, either now or as soon as safe. */
281 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
282 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
285 /* Lay out a RECORD_TYPE type (a C struct).
286 This means laying out the fields, determining their positions,
287 and computing the overall size and required alignment of the record.
288 Note that if you set the TYPE_ALIGN before calling this
289 then the struct is aligned to at least that boundary.
291 If the type has basetypes, you must call layout_basetypes
292 before calling this function.
294 The return value is a list of static members of the record.
295 They still need to be laid out. */
302 #ifdef STRUCTURE_SIZE_BOUNDARY
303 unsigned record_align
= MAX (STRUCTURE_SIZE_BOUNDARY
, TYPE_ALIGN (rec
));
305 unsigned record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (rec
));
307 /* These must be laid out *after* the record is. */
308 tree pending_statics
= NULL_TREE
;
309 /* Record size so far is CONST_SIZE + VAR_SIZE bits,
310 where CONST_SIZE is an integer
311 and VAR_SIZE is a tree expression.
312 If VAR_SIZE is null, the size is just CONST_SIZE.
313 Naturally we try to avoid using VAR_SIZE. */
314 register int const_size
= 0;
315 register tree var_size
= 0;
316 /* Once we start using VAR_SIZE, this is the maximum alignment
317 that we know VAR_SIZE has. */
318 register int var_align
= BITS_PER_UNIT
;
321 for (field
= TYPE_FIELDS (rec
); field
; field
= TREE_CHAIN (field
))
323 register int known_align
= var_size
? var_align
: const_size
;
324 register int desired_align
;
326 /* If FIELD is static, then treat it like a separate variable,
327 not really like a structure field.
328 If it is a FUNCTION_DECL, it's a method.
329 In both cases, all we do is lay out the decl,
330 and we do it *after* the record is laid out. */
332 if (TREE_STATIC (field
))
334 pending_statics
= tree_cons (NULL_TREE
, field
, pending_statics
);
337 /* Enumerators and enum types which are local to this class need not
338 be laid out. Likewise for initialized constant fields. */
339 if (TREE_CODE (field
) != FIELD_DECL
)
342 /* Lay out the field so we know what alignment it needs.
343 For a packed field, use the alignment as specified,
344 disregarding what the type would want. */
345 if (DECL_PACKED (field
))
346 desired_align
= DECL_ALIGN (field
);
347 layout_decl (field
, known_align
);
348 if (! DECL_PACKED (field
))
349 desired_align
= DECL_ALIGN (field
);
350 /* Some targets (i.e. VMS) limit struct field alignment
351 to a lower boundary than alignment of variables. */
352 #ifdef BIGGEST_FIELD_ALIGNMENT
353 desired_align
= MIN (desired_align
, BIGGEST_FIELD_ALIGNMENT
);
356 /* Record must have at least as much alignment as any field.
357 Otherwise, the alignment of the field within the record
360 #ifndef PCC_BITFIELD_TYPE_MATTERS
361 record_align
= MAX (record_align
, desired_align
);
363 if (PCC_BITFIELD_TYPE_MATTERS
&& TREE_TYPE (field
) != error_mark_node
364 && DECL_BIT_FIELD_TYPE (field
)
365 && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field
))))
367 /* For these machines, a zero-length field does not
368 affect the alignment of the structure as a whole.
369 It does, however, affect the alignment of the next field
370 within the structure. */
371 if (! integer_zerop (DECL_SIZE (field
)))
372 record_align
= MAX (record_align
, desired_align
);
373 else if (! DECL_PACKED (field
))
374 desired_align
= TYPE_ALIGN (TREE_TYPE (field
));
375 /* A named bit field of declared type `int'
376 forces the entire structure to have `int' alignment. */
377 if (DECL_NAME (field
) != 0)
379 int type_align
= TYPE_ALIGN (TREE_TYPE (field
));
380 if (maximum_field_alignment
!= 0)
381 type_align
= MIN (type_align
, maximum_field_alignment
);
382 else if (flag_pack_struct
)
383 type_align
= MIN (type_align
, BITS_PER_UNIT
);
385 record_align
= MAX (record_align
, type_align
);
389 record_align
= MAX (record_align
, desired_align
);
392 /* Does this field automatically have alignment it needs
393 by virtue of the fields that precede it and the record's
396 if (const_size
% desired_align
!= 0
397 || (var_align
% desired_align
!= 0
400 /* No, we need to skip space before this field.
401 Bump the cumulative size to multiple of field alignment. */
404 || var_align
% desired_align
== 0)
406 = CEIL (const_size
, desired_align
) * desired_align
;
410 var_size
= size_binop (PLUS_EXPR
, var_size
,
411 size_int (const_size
));
413 var_size
= round_up (var_size
, desired_align
);
414 var_align
= MIN (var_align
, desired_align
);
418 #ifdef PCC_BITFIELD_TYPE_MATTERS
419 if (PCC_BITFIELD_TYPE_MATTERS
420 && TREE_CODE (field
) == FIELD_DECL
421 && TREE_TYPE (field
) != error_mark_node
422 && DECL_BIT_FIELD_TYPE (field
)
423 && !DECL_PACKED (field
)
424 /* If #pragma pack is in effect, turn off this feature. */
425 && maximum_field_alignment
== 0
427 && !integer_zerop (DECL_SIZE (field
)))
429 int type_align
= TYPE_ALIGN (TREE_TYPE (field
));
430 register tree dsize
= DECL_SIZE (field
);
431 int field_size
= TREE_INT_CST_LOW (dsize
);
433 /* A bit field may not span the unit of alignment of its type.
434 Advance to next boundary if necessary. */
435 /* ??? There is some uncertainty here as to what
436 should be done if type_align is less than the width of the type.
437 That can happen because the width exceeds BIGGEST_ALIGNMENT
438 or because it exceeds maximum_field_alignment. */
439 if (const_size
/ type_align
440 != (const_size
+ (field_size
% type_align
) - 1) / type_align
)
441 const_size
= CEIL (const_size
, type_align
) * type_align
;
445 /* No existing machine description uses this parameter.
446 So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
447 #ifdef BITFIELD_NBYTES_LIMITED
448 if (BITFIELD_NBYTES_LIMITED
449 && TREE_CODE (field
) == FIELD_DECL
450 && TREE_TYPE (field
) != error_mark_node
451 && DECL_BIT_FIELD_TYPE (field
)
452 && !DECL_PACKED (field
)
453 && !integer_zerop (DECL_SIZE (field
)))
455 int type_align
= TYPE_ALIGN (TREE_TYPE (field
));
456 register tree dsize
= DECL_SIZE (field
);
457 int field_size
= TREE_INT_CST_LOW (dsize
);
459 if (maximum_field_alignment
!= 0)
460 type_align
= MIN (type_align
, maximum_field_alignment
);
461 else if (flag_pack_struct
)
462 type_align
= MIN (type_align
, BITS_PER_UNIT
);
464 /* A bit field may not span the unit of alignment of its type.
465 Advance to next boundary if necessary. */
466 if (const_size
/ type_align
467 != (const_size
+ field_size
- 1) / type_align
)
468 const_size
= CEIL (const_size
, type_align
) * type_align
;
472 /* Size so far becomes the position of this field. */
474 if (var_size
&& const_size
)
475 DECL_FIELD_BITPOS (field
)
476 = size_binop (PLUS_EXPR
, var_size
, size_int (const_size
));
478 DECL_FIELD_BITPOS (field
) = var_size
;
481 DECL_FIELD_BITPOS (field
) = size_int (const_size
);
483 /* If this field ended up more aligned than we thought it
484 would be (we approximate this by seeing if its position
485 changed), lay out the field again; perhaps we can use an
486 integral mode for it now. */
487 if (known_align
!= const_size
)
488 layout_decl (field
, const_size
);
491 /* Now add size of this field to the size of the record. */
494 register tree dsize
= DECL_SIZE (field
);
496 /* This can happen when we have an invalid nested struct definition,
497 such as struct j { struct j { int i; } }. The error message is
498 printed in finish_struct. */
501 else if (TREE_CODE (dsize
) == INTEGER_CST
502 && TREE_INT_CST_HIGH (dsize
) == 0
503 && TREE_INT_CST_LOW (dsize
) + const_size
> const_size
)
504 /* Use const_size if there's no overflow. */
505 const_size
+= TREE_INT_CST_LOW (dsize
);
511 var_size
= size_binop (PLUS_EXPR
, var_size
, dsize
);
516 /* Work out the total size and alignment of the record
517 as one expression and store in the record type.
518 Round it up to a multiple of the record's alignment. */
522 TYPE_SIZE (rec
) = size_int (const_size
);
528 = size_binop (PLUS_EXPR
, var_size
, size_int (const_size
));
529 TYPE_SIZE (rec
) = var_size
;
532 /* Determine the desired alignment. */
533 #ifdef ROUND_TYPE_ALIGN
534 TYPE_ALIGN (rec
) = ROUND_TYPE_ALIGN (rec
, TYPE_ALIGN (rec
), record_align
);
536 TYPE_ALIGN (rec
) = MAX (TYPE_ALIGN (rec
), record_align
);
539 #ifdef ROUND_TYPE_SIZE
540 TYPE_SIZE (rec
) = ROUND_TYPE_SIZE (rec
, TYPE_SIZE (rec
), TYPE_ALIGN (rec
));
542 /* Round the size up to be a multiple of the required alignment */
543 TYPE_SIZE (rec
) = round_up (TYPE_SIZE (rec
), TYPE_ALIGN (rec
));
546 return pending_statics
;
549 /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
550 Lay out all the fields, set their positions to zero,
551 and compute the size and alignment of the union (maximum of any field).
552 Note that if you set the TYPE_ALIGN before calling this
553 then the union align is aligned to at least that boundary. */
560 #ifdef STRUCTURE_SIZE_BOUNDARY
561 unsigned union_align
= STRUCTURE_SIZE_BOUNDARY
;
563 unsigned union_align
= BITS_PER_UNIT
;
566 /* The size of the union, based on the fields scanned so far,
567 is max (CONST_SIZE, VAR_SIZE).
568 VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
569 register int const_size
= 0;
570 register tree var_size
= 0;
572 /* If this is a QUAL_UNION_TYPE, we want to process the fields in
573 the reverse order in building the COND_EXPR that denotes its
574 size. We reverse them again later. */
575 if (TREE_CODE (rec
) == QUAL_UNION_TYPE
)
576 TYPE_FIELDS (rec
) = nreverse (TYPE_FIELDS (rec
));
578 for (field
= TYPE_FIELDS (rec
); field
; field
= TREE_CHAIN (field
))
580 /* Enums which are local to this class need not be laid out. */
581 if (TREE_CODE (field
) == CONST_DECL
|| TREE_CODE (field
) == TYPE_DECL
)
584 layout_decl (field
, 0);
585 DECL_FIELD_BITPOS (field
) = size_int (0);
587 /* Union must be at least as aligned as any field requires. */
589 union_align
= MAX (union_align
, DECL_ALIGN (field
));
591 #ifdef PCC_BITFIELD_TYPE_MATTERS
592 /* On the m88000, a bit field of declare type `int'
593 forces the entire union to have `int' alignment. */
594 if (PCC_BITFIELD_TYPE_MATTERS
&& DECL_BIT_FIELD_TYPE (field
))
595 union_align
= MAX (union_align
, TYPE_ALIGN (TREE_TYPE (field
)));
598 if (TREE_CODE (rec
) == UNION_TYPE
)
600 /* Set union_size to max (decl_size, union_size).
601 There are more and less general ways to do this.
602 Use only CONST_SIZE unless forced to use VAR_SIZE. */
604 if (TREE_CODE (DECL_SIZE (field
)) == INTEGER_CST
)
606 = MAX (const_size
, TREE_INT_CST_LOW (DECL_SIZE (field
)));
607 else if (var_size
== 0)
608 var_size
= DECL_SIZE (field
);
610 var_size
= size_binop (MAX_EXPR
, var_size
, DECL_SIZE (field
));
612 else if (TREE_CODE (rec
) == QUAL_UNION_TYPE
)
613 var_size
= fold (build (COND_EXPR
, sizetype
, DECL_QUALIFIER (field
),
615 var_size
? var_size
: integer_zero_node
));
618 if (TREE_CODE (rec
) == QUAL_UNION_TYPE
)
619 TYPE_FIELDS (rec
) = nreverse (TYPE_FIELDS (rec
));
621 /* Determine the ultimate size of the union (in bytes). */
622 if (NULL
== var_size
)
623 TYPE_SIZE (rec
) = size_int (CEIL (const_size
, BITS_PER_UNIT
)
625 else if (const_size
== 0)
626 TYPE_SIZE (rec
) = var_size
;
628 TYPE_SIZE (rec
) = size_binop (MAX_EXPR
, var_size
,
629 round_up (size_int (const_size
),
632 /* Determine the desired alignment. */
633 #ifdef ROUND_TYPE_ALIGN
634 TYPE_ALIGN (rec
) = ROUND_TYPE_ALIGN (rec
, TYPE_ALIGN (rec
), union_align
);
636 TYPE_ALIGN (rec
) = MAX (TYPE_ALIGN (rec
), union_align
);
639 #ifdef ROUND_TYPE_SIZE
640 TYPE_SIZE (rec
) = ROUND_TYPE_SIZE (rec
, TYPE_SIZE (rec
), TYPE_ALIGN (rec
));
642 /* Round the size up to be a multiple of the required alignment */
643 TYPE_SIZE (rec
) = round_up (TYPE_SIZE (rec
), TYPE_ALIGN (rec
));
647 /* Calculate the mode, size, and alignment for TYPE.
648 For an array type, calculate the element separation as well.
649 Record TYPE on the chain of permanent or temporary types
650 so that dbxout will find out about it.
652 TYPE_SIZE of a type is nonzero if the type has been laid out already.
653 layout_type does nothing on such a type.
655 If the type is incomplete, its TYPE_SIZE remains zero. */
662 tree pending_statics
;
667 /* Do nothing if type has been laid out before. */
668 if (TYPE_SIZE (type
))
671 /* Make sure all nodes we allocate are not momentary;
672 they must last past the current statement. */
673 old
= suspend_momentary ();
675 /* Put all our nodes into the same obstack as the type. Also,
676 make expressions saveable (this is a no-op for permanent types). */
678 push_obstacks (TYPE_OBSTACK (type
), TYPE_OBSTACK (type
));
679 saveable_allocation ();
681 switch (TREE_CODE (type
))
684 /* This kind of type is the responsibility
685 of the language-specific code. */
691 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
692 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
693 TREE_UNSIGNED (type
) = 1;
695 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
697 TYPE_SIZE (type
) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
701 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
702 TYPE_SIZE (type
) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
706 TREE_UNSIGNED (type
) = TREE_UNSIGNED (TREE_TYPE (type
));
708 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
709 (TREE_CODE (TREE_TYPE (type
)) == INTEGER_TYPE
710 ? MODE_COMPLEX_INT
: MODE_COMPLEX_FLOAT
),
712 TYPE_SIZE (type
) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
716 TYPE_SIZE (type
) = size_zero_node
;
717 TYPE_ALIGN (type
) = 1;
718 TYPE_MODE (type
) = VOIDmode
;
722 TYPE_SIZE (type
) = size_int (POINTER_SIZE
);
723 TYPE_MODE (type
) = ptr_mode
;
728 TYPE_MODE (type
) = mode_for_size (2 * POINTER_SIZE
, MODE_INT
, 0);
729 TYPE_SIZE (type
) = size_int (2 * POINTER_SIZE
);
734 TYPE_MODE (type
) = ptr_mode
;
735 TYPE_SIZE (type
) = size_int (POINTER_SIZE
);
736 TREE_UNSIGNED (type
) = 1;
737 TYPE_PRECISION (type
) = POINTER_SIZE
;
742 register tree index
= TYPE_DOMAIN (type
);
743 register tree element
= TREE_TYPE (type
);
745 build_pointer_type (element
);
747 /* We need to know both bounds in order to compute the size. */
748 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
749 && TYPE_SIZE (element
))
751 tree ub
= TYPE_MAX_VALUE (index
);
752 tree lb
= TYPE_MIN_VALUE (index
);
755 /* If UB is max (lb - 1, x), remove the MAX_EXPR since the
756 test for negative below covers it. */
757 if (TREE_CODE (ub
) == MAX_EXPR
758 && TREE_CODE (TREE_OPERAND (ub
, 0)) == MINUS_EXPR
759 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub
, 0), 1))
760 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub
, 0), 0),
762 ub
= TREE_OPERAND (ub
, 1);
763 else if (TREE_CODE (ub
) == MAX_EXPR
764 && TREE_CODE (TREE_OPERAND (ub
, 1)) == MINUS_EXPR
765 && integer_onep (TREE_OPERAND (TREE_OPERAND (ub
, 1), 1))
766 && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub
, 1),
769 ub
= TREE_OPERAND (ub
, 0);
771 length
= size_binop (PLUS_EXPR
, size_one_node
,
772 size_binop (MINUS_EXPR
, ub
, lb
));
774 /* If neither bound is a constant and sizetype is signed, make
775 sure the size is never negative. We should really do this
776 if *either* bound is non-constant, but this is the best
777 compromise between C and Ada. */
778 if (! TREE_UNSIGNED (sizetype
)
779 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
780 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
781 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
783 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, length
,
784 TYPE_SIZE (element
));
787 /* Now round the alignment and size,
788 using machine-dependent criteria if any. */
790 #ifdef ROUND_TYPE_ALIGN
792 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
794 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
797 #ifdef ROUND_TYPE_SIZE
798 if (TYPE_SIZE (type
) != 0)
800 = ROUND_TYPE_SIZE (type
, TYPE_SIZE (type
), TYPE_ALIGN (type
));
803 TYPE_MODE (type
) = BLKmode
;
804 if (TYPE_SIZE (type
) != 0
805 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
806 /* BLKmode elements force BLKmode aggregate;
807 else extract/store fields may lose. */
808 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
809 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
812 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type
)),
815 if (STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
816 && TYPE_ALIGN (type
) < TREE_INT_CST_LOW (TYPE_SIZE (type
))
817 && TYPE_MODE (type
) != BLKmode
)
819 TYPE_NO_FORCE_BLK (type
) = 1;
820 TYPE_MODE (type
) = BLKmode
;
827 pending_statics
= layout_record (type
);
828 TYPE_MODE (type
) = BLKmode
;
829 if (TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
)
832 /* A record which has any BLKmode members must itself be BLKmode;
833 it can't go in a register.
834 Unless the member is BLKmode only because it isn't aligned. */
835 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
839 if (TREE_CODE (field
) != FIELD_DECL
)
842 if (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
843 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
)))
846 if (TREE_CODE (DECL_FIELD_BITPOS (field
)) != INTEGER_CST
)
849 bitpos
= TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field
));
851 /* Must be BLKmode if any field crosses a word boundary,
852 since extract_bit_field can't handle that in registers. */
853 if (bitpos
/ BITS_PER_WORD
854 != ((TREE_INT_CST_LOW (DECL_SIZE (field
)) + bitpos
- 1)
856 /* But there is no problem if the field is entire words. */
857 && TREE_INT_CST_LOW (DECL_SIZE (field
)) % BITS_PER_WORD
== 0)
862 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type
)),
865 /* If structure's known alignment is less than
866 what the scalar mode would need, and it matters,
867 then stick with BLKmode. */
869 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
870 || (TYPE_ALIGN (type
)
871 >= TREE_INT_CST_LOW (TYPE_SIZE (type
)))))
873 if (TYPE_MODE (type
) != BLKmode
)
874 /* If this is the only reason this type is BLKmode,
875 then don't force containing types to be BLKmode. */
876 TYPE_NO_FORCE_BLK (type
) = 1;
877 TYPE_MODE (type
) = BLKmode
;
883 /* Lay out any static members. This is done now
884 because their type may use the record's type. */
885 while (pending_statics
)
887 layout_decl (TREE_VALUE (pending_statics
), 0);
888 pending_statics
= TREE_CHAIN (pending_statics
);
893 case QUAL_UNION_TYPE
:
895 TYPE_MODE (type
) = BLKmode
;
896 if (TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
897 /* If structure's known alignment is less than
898 what the scalar mode would need, and it matters,
899 then stick with BLKmode. */
900 && (! STRICT_ALIGNMENT
901 || TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
902 || TYPE_ALIGN (type
) >= TREE_INT_CST_LOW (TYPE_SIZE (type
))))
905 /* A union which has any BLKmode members must itself be BLKmode;
906 it can't go in a register.
907 Unless the member is BLKmode only because it isn't aligned. */
908 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
910 if (TREE_CODE (field
) != FIELD_DECL
)
913 if (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
914 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
)))
919 = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type
)),
926 /* Pascal and Chill types */
927 case BOOLEAN_TYPE
: /* store one byte/boolean for now. */
928 TYPE_MODE (type
) = QImode
;
929 TYPE_SIZE (type
) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
930 TYPE_PRECISION (type
) = 1;
931 TYPE_ALIGN (type
) = GET_MODE_ALIGNMENT (TYPE_MODE (type
));
932 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
933 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
934 TREE_UNSIGNED (type
) = 1;
938 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
939 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
)
943 #ifndef SET_WORD_SIZE
944 #define SET_WORD_SIZE BITS_PER_WORD
946 int alignment
= set_alignment
? set_alignment
: SET_WORD_SIZE
;
948 TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type
)))
949 - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type
))) + 1;
951 = ((size_in_bits
+ alignment
- 1) / alignment
) * alignment
;
952 if (rounded_size
> alignment
)
953 TYPE_MODE (type
) = BLKmode
;
955 TYPE_MODE (type
) = mode_for_size (alignment
, MODE_INT
, 1);
956 TYPE_SIZE (type
) = size_int (rounded_size
);
957 TYPE_ALIGN (type
) = alignment
;
958 TYPE_PRECISION (type
) = size_in_bits
;
963 /* The size may vary in different languages, so the language front end
964 should fill in the size. */
965 TYPE_ALIGN (type
) = BIGGEST_ALIGNMENT
;
966 TYPE_MODE (type
) = BLKmode
;
973 /* Normally, use the alignment corresponding to the mode chosen.
974 However, where strict alignment is not required, avoid
975 over-aligning structures, since most compilers do not do this
978 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
980 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
981 && TREE_CODE (type
) != QUAL_UNION_TYPE
982 && TREE_CODE (type
) != ARRAY_TYPE
)))
983 TYPE_ALIGN (type
) = GET_MODE_ALIGNMENT (TYPE_MODE (type
));
985 /* Evaluate nonconstant size only once, either now or as soon as safe. */
986 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
987 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
989 /* Also layout any other variants of the type. */
990 if (TYPE_NEXT_VARIANT (type
)
991 || type
!= TYPE_MAIN_VARIANT (type
))
994 /* Record layout info of this variant. */
995 tree size
= TYPE_SIZE (type
);
996 int align
= TYPE_ALIGN (type
);
997 enum machine_mode mode
= TYPE_MODE (type
);
999 /* Copy it into all variants. */
1000 for (variant
= TYPE_MAIN_VARIANT (type
);
1002 variant
= TYPE_NEXT_VARIANT (variant
))
1004 TYPE_SIZE (variant
) = size
;
1005 TYPE_ALIGN (variant
) = align
;
1006 TYPE_MODE (variant
) = mode
;
1011 resume_momentary (old
);
1014 /* Create and return a type for signed integers of PRECISION bits. */
1017 make_signed_type (precision
)
1020 register tree type
= make_node (INTEGER_TYPE
);
1022 TYPE_PRECISION (type
) = precision
;
1024 /* Create the extreme values based on the number of bits. */
1026 TYPE_MIN_VALUE (type
)
1027 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1028 ? 0 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
1029 (((HOST_WIDE_INT
) (-1)
1030 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1031 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
1033 TYPE_MAX_VALUE (type
)
1034 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1035 ? -1 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
1036 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1037 ? (((HOST_WIDE_INT
) 1
1038 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
1041 /* Give this type's extreme values this type as their type. */
1043 TREE_TYPE (TYPE_MIN_VALUE (type
)) = type
;
1044 TREE_TYPE (TYPE_MAX_VALUE (type
)) = type
;
1046 /* The first type made with this or `make_unsigned_type'
1047 is the type for size values. */
1054 /* Lay out the type: set its alignment, size, etc. */
1061 /* Create and return a type for unsigned integers of PRECISION bits. */
1064 make_unsigned_type (precision
)
1067 register tree type
= make_node (INTEGER_TYPE
);
1069 TYPE_PRECISION (type
) = precision
;
1071 /* The first type made with this or `make_signed_type'
1072 is the type for size values. */
1079 fixup_unsigned_type (type
);
1083 /* Set the extreme values of TYPE based on its precision in bits,
1084 then lay it out. Used when make_signed_type won't do
1085 because the tree code is not INTEGER_TYPE.
1086 E.g. for Pascal, when the -fsigned-char option is given. */
1089 fixup_signed_type (type
)
1092 register int precision
= TYPE_PRECISION (type
);
1094 TYPE_MIN_VALUE (type
)
1095 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1096 ? 0 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
1097 (((HOST_WIDE_INT
) (-1)
1098 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1099 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
1101 TYPE_MAX_VALUE (type
)
1102 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1103 ? -1 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
1104 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1105 ? (((HOST_WIDE_INT
) 1
1106 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
1109 TREE_TYPE (TYPE_MIN_VALUE (type
)) = type
;
1110 TREE_TYPE (TYPE_MAX_VALUE (type
)) = type
;
1112 /* Lay out the type: set its alignment, size, etc. */
1117 /* Set the extreme values of TYPE based on its precision in bits,
1118 then lay it out. This is used both in `make_unsigned_type'
1119 and for enumeral types. */
1122 fixup_unsigned_type (type
)
1125 register int precision
= TYPE_PRECISION (type
);
1127 TYPE_MIN_VALUE (type
) = build_int_2 (0, 0);
1128 TYPE_MAX_VALUE (type
)
1129 = build_int_2 (precision
- HOST_BITS_PER_WIDE_INT
>= 0
1130 ? -1 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
1131 precision
- HOST_BITS_PER_WIDE_INT
> 0
1132 ? ((unsigned HOST_WIDE_INT
) ~0
1133 >> (HOST_BITS_PER_WIDE_INT
1134 - (precision
- HOST_BITS_PER_WIDE_INT
)))
1136 TREE_TYPE (TYPE_MIN_VALUE (type
)) = type
;
1137 TREE_TYPE (TYPE_MAX_VALUE (type
)) = type
;
1139 /* Lay out the type: set its alignment, size, etc. */
1144 /* Find the best machine mode to use when referencing a bit field of length
1145 BITSIZE bits starting at BITPOS.
1147 The underlying object is known to be aligned to a boundary of ALIGN bits.
1148 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
1149 larger than LARGEST_MODE (usually SImode).
1151 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
1152 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
1153 mode meeting these conditions.
1155 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
1156 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
1157 all the conditions. */
1160 get_best_mode (bitsize
, bitpos
, align
, largest_mode
, volatilep
)
1161 int bitsize
, bitpos
;
1163 enum machine_mode largest_mode
;
1166 enum machine_mode mode
;
1169 /* Find the narrowest integer mode that contains the bit field. */
1170 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
1171 mode
= GET_MODE_WIDER_MODE (mode
))
1173 unit
= GET_MODE_BITSIZE (mode
);
1174 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
)
1178 if (mode
== MAX_MACHINE_MODE
1179 /* It is tempting to omit the following line
1180 if STRICT_ALIGNMENT is true.
1181 But that is incorrect, since if the bitfield uses part of 3 bytes
1182 and we use a 4-byte mode, we could get a spurious segv
1183 if the extra 4th byte is past the end of memory.
1184 (Though at least one Unix compiler ignores this problem:
1185 that on the Sequent 386 machine. */
1186 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
1187 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
1190 if (SLOW_BYTE_ACCESS
&& ! volatilep
)
1192 enum machine_mode wide_mode
= VOIDmode
, tmode
;
1194 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
1195 tmode
= GET_MODE_WIDER_MODE (tmode
))
1197 unit
= GET_MODE_BITSIZE (tmode
);
1198 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
1199 && unit
<= BITS_PER_WORD
1200 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
1201 && (largest_mode
== VOIDmode
1202 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
1206 if (wide_mode
!= VOIDmode
)
1213 /* Save all variables describing the current status into the structure *P.
1214 This is used before starting a nested function. */
1217 save_storage_status (p
)
1220 #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
1221 p
->pending_sizes
= pending_sizes
;
1222 p
->immediate_size_expand
= immediate_size_expand
;
1226 /* Restore all variables describing the current status from the structure *P.
1227 This is used after a nested function. */
1230 restore_storage_status (p
)
1234 pending_sizes
= p
->pending_sizes
;
1235 immediate_size_expand
= p
->immediate_size_expand
;