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, 2005 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, 51 Franklin Street, Fifth Floor, Boston, MA
25 #include "coretypes.h"
37 #include "langhooks.h"
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
= TARGET_DEFAULT_PACK_STRUCT
* BITS_PER_UNIT
;
48 /* ... and its original value in bytes, specified via -fpack-struct=<value>. */
49 unsigned int initial_max_fld_align
= TARGET_DEFAULT_PACK_STRUCT
;
51 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
52 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
53 called only by a front end. */
54 static int reference_types_internal
= 0;
56 static void finalize_record_size (record_layout_info
);
57 static void finalize_type_size (tree
);
58 static void place_union_field (record_layout_info
, tree
);
59 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
60 static int excess_unit_span (HOST_WIDE_INT
, HOST_WIDE_INT
, HOST_WIDE_INT
,
63 extern void debug_rli (record_layout_info
);
65 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
67 static GTY(()) tree pending_sizes
;
69 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
73 internal_reference_types (void)
75 reference_types_internal
= 1;
78 /* Get a list of all the objects put on the pending sizes list. */
81 get_pending_sizes (void)
83 tree chain
= pending_sizes
;
89 /* Add EXPR to the pending sizes list. */
92 put_pending_size (tree expr
)
94 /* Strip any simple arithmetic from EXPR to see if it has an underlying
96 expr
= skip_simple_arithmetic (expr
);
98 if (TREE_CODE (expr
) == SAVE_EXPR
)
99 pending_sizes
= tree_cons (NULL_TREE
, expr
, pending_sizes
);
102 /* Put a chain of objects into the pending sizes list, which must be
106 put_pending_sizes (tree chain
)
108 gcc_assert (!pending_sizes
);
109 pending_sizes
= chain
;
112 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
113 to serve as the actual size-expression for a type or decl. */
116 variable_size (tree size
)
120 /* If the language-processor is to take responsibility for variable-sized
121 items (e.g., languages which have elaboration procedures like Ada),
122 just return SIZE unchanged. Likewise for self-referential sizes and
124 if (TREE_CONSTANT (size
)
125 || lang_hooks
.decls
.global_bindings_p () < 0
126 || CONTAINS_PLACEHOLDER_P (size
))
129 size
= save_expr (size
);
131 /* If an array with a variable number of elements is declared, and
132 the elements require destruction, we will emit a cleanup for the
133 array. That cleanup is run both on normal exit from the block
134 and in the exception-handler for the block. Normally, when code
135 is used in both ordinary code and in an exception handler it is
136 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
137 not wish to do that here; the array-size is the same in both
139 save
= skip_simple_arithmetic (size
);
141 if (cfun
&& cfun
->x_dont_save_pending_sizes_p
)
142 /* The front-end doesn't want us to keep a list of the expressions
143 that determine sizes for variable size objects. Trust it. */
146 if (lang_hooks
.decls
.global_bindings_p ())
148 if (TREE_CONSTANT (size
))
149 error ("type size can%'t be explicitly evaluated");
151 error ("variable-size type declared outside of any function");
153 return size_one_node
;
156 put_pending_size (save
);
161 #ifndef MAX_FIXED_MODE_SIZE
162 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
165 /* Return the machine mode to use for a nonscalar of SIZE bits. The
166 mode must be in class CLASS, and have exactly that many value bits;
167 it may have padding as well. If LIMIT is nonzero, modes of wider
168 than MAX_FIXED_MODE_SIZE will not be used. */
171 mode_for_size (unsigned int size
, enum mode_class
class, int limit
)
173 enum machine_mode mode
;
175 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
178 /* Get the first mode which has this size, in the specified class. */
179 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
180 mode
= GET_MODE_WIDER_MODE (mode
))
181 if (GET_MODE_PRECISION (mode
) == size
)
187 /* Similar, except passed a tree node. */
190 mode_for_size_tree (tree size
, enum mode_class
class, int limit
)
192 if (TREE_CODE (size
) != INTEGER_CST
193 || TREE_OVERFLOW (size
)
194 /* What we really want to say here is that the size can fit in a
195 host integer, but we know there's no way we'd find a mode for
196 this many bits, so there's no point in doing the precise test. */
197 || compare_tree_int (size
, 1000) > 0)
200 return mode_for_size (tree_low_cst (size
, 1), class, limit
);
203 /* Similar, but never return BLKmode; return the narrowest mode that
204 contains at least the requested number of value bits. */
207 smallest_mode_for_size (unsigned int size
, enum mode_class
class)
209 enum machine_mode mode
;
211 /* Get the first mode which has at least this size, in the
213 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
214 mode
= GET_MODE_WIDER_MODE (mode
))
215 if (GET_MODE_PRECISION (mode
) >= size
)
221 /* Find an integer mode of the exact same size, or BLKmode on failure. */
224 int_mode_for_mode (enum machine_mode mode
)
226 switch (GET_MODE_CLASS (mode
))
229 case MODE_PARTIAL_INT
:
232 case MODE_COMPLEX_INT
:
233 case MODE_COMPLEX_FLOAT
:
235 case MODE_VECTOR_INT
:
236 case MODE_VECTOR_FLOAT
:
237 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
244 /* ... fall through ... */
254 /* Return the alignment of MODE. This will be bounded by 1 and
255 BIGGEST_ALIGNMENT. */
258 get_mode_alignment (enum machine_mode mode
)
260 return MIN (BIGGEST_ALIGNMENT
, MAX (1, mode_base_align
[mode
]*BITS_PER_UNIT
));
264 /* Subroutine of layout_decl: Force alignment required for the data type.
265 But if the decl itself wants greater alignment, don't override that. */
268 do_type_align (tree type
, tree decl
)
270 if (TYPE_ALIGN (type
) > DECL_ALIGN (decl
))
272 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
273 if (TREE_CODE (decl
) == FIELD_DECL
)
274 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
278 /* Set the size, mode and alignment of a ..._DECL node.
279 TYPE_DECL does need this for C++.
280 Note that LABEL_DECL and CONST_DECL nodes do not need this,
281 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
282 Don't call layout_decl for them.
284 KNOWN_ALIGN is the amount of alignment we can assume this
285 decl has with no special effort. It is relevant only for FIELD_DECLs
286 and depends on the previous fields.
287 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
288 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
289 the record will be aligned to suit. */
292 layout_decl (tree decl
, unsigned int known_align
)
294 tree type
= TREE_TYPE (decl
);
295 enum tree_code code
= TREE_CODE (decl
);
298 if (code
== CONST_DECL
)
301 gcc_assert (code
== VAR_DECL
|| code
== PARM_DECL
|| code
== RESULT_DECL
302 || code
== TYPE_DECL
||code
== FIELD_DECL
);
304 rtl
= DECL_RTL_IF_SET (decl
);
306 if (type
== error_mark_node
)
307 type
= void_type_node
;
309 /* Usually the size and mode come from the data type without change,
310 however, the front-end may set the explicit width of the field, so its
311 size may not be the same as the size of its type. This happens with
312 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
313 also happens with other fields. For example, the C++ front-end creates
314 zero-sized fields corresponding to empty base classes, and depends on
315 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
316 size in bytes from the size in bits. If we have already set the mode,
317 don't set it again since we can be called twice for FIELD_DECLs. */
319 DECL_UNSIGNED (decl
) = TYPE_UNSIGNED (type
);
320 if (DECL_MODE (decl
) == VOIDmode
)
321 DECL_MODE (decl
) = TYPE_MODE (type
);
323 if (DECL_SIZE (decl
) == 0)
325 DECL_SIZE (decl
) = TYPE_SIZE (type
);
326 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
328 else if (DECL_SIZE_UNIT (decl
) == 0)
329 DECL_SIZE_UNIT (decl
)
330 = fold_convert (sizetype
, size_binop (CEIL_DIV_EXPR
, DECL_SIZE (decl
),
333 if (code
!= FIELD_DECL
)
334 /* For non-fields, update the alignment from the type. */
335 do_type_align (type
, decl
);
337 /* For fields, it's a bit more complicated... */
339 bool old_user_align
= DECL_USER_ALIGN (decl
);
341 if (DECL_BIT_FIELD (decl
))
343 DECL_BIT_FIELD_TYPE (decl
) = type
;
345 /* A zero-length bit-field affects the alignment of the next
347 if (integer_zerop (DECL_SIZE (decl
))
348 && ! DECL_PACKED (decl
)
349 && ! targetm
.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl
)))
351 #ifdef PCC_BITFIELD_TYPE_MATTERS
352 if (PCC_BITFIELD_TYPE_MATTERS
)
353 do_type_align (type
, decl
);
357 #ifdef EMPTY_FIELD_BOUNDARY
358 if (EMPTY_FIELD_BOUNDARY
> DECL_ALIGN (decl
))
360 DECL_ALIGN (decl
) = EMPTY_FIELD_BOUNDARY
;
361 DECL_USER_ALIGN (decl
) = 0;
367 /* See if we can use an ordinary integer mode for a bit-field.
368 Conditions are: a fixed size that is correct for another mode
369 and occupying a complete byte or bytes on proper boundary. */
370 if (TYPE_SIZE (type
) != 0
371 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
372 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
)
374 enum machine_mode xmode
375 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
379 || known_align
>= GET_MODE_ALIGNMENT (xmode
)))
381 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
383 DECL_MODE (decl
) = xmode
;
384 DECL_BIT_FIELD (decl
) = 0;
388 /* Turn off DECL_BIT_FIELD if we won't need it set. */
389 if (TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
390 && known_align
>= TYPE_ALIGN (type
)
391 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
))
392 DECL_BIT_FIELD (decl
) = 0;
394 else if (DECL_PACKED (decl
) && DECL_USER_ALIGN (decl
))
395 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
396 round up; we'll reduce it again below. We want packing to
397 supersede USER_ALIGN inherited from the type, but defer to
398 alignment explicitly specified on the field decl. */;
400 do_type_align (type
, decl
);
402 /* If the field is of variable size, we can't misalign it since we
403 have no way to make a temporary to align the result. But this
404 isn't an issue if the decl is not addressable. Likewise if it
407 Note that do_type_align may set DECL_USER_ALIGN, so we need to
408 check old_user_align instead. */
409 if (DECL_PACKED (decl
)
411 && (DECL_NONADDRESSABLE_P (decl
)
412 || DECL_SIZE_UNIT (decl
) == 0
413 || TREE_CODE (DECL_SIZE_UNIT (decl
)) == INTEGER_CST
))
414 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
416 if (! DECL_USER_ALIGN (decl
) && ! DECL_PACKED (decl
))
418 /* Some targets (i.e. i386, VMS) limit struct field alignment
419 to a lower boundary than alignment of variables unless
420 it was overridden by attribute aligned. */
421 #ifdef BIGGEST_FIELD_ALIGNMENT
423 = MIN (DECL_ALIGN (decl
), (unsigned) BIGGEST_FIELD_ALIGNMENT
);
425 #ifdef ADJUST_FIELD_ALIGN
426 DECL_ALIGN (decl
) = ADJUST_FIELD_ALIGN (decl
, DECL_ALIGN (decl
));
430 /* Should this be controlled by DECL_USER_ALIGN, too? */
431 if (maximum_field_alignment
!= 0)
432 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), maximum_field_alignment
);
435 /* Evaluate nonconstant size only once, either now or as soon as safe. */
436 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
437 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
438 if (DECL_SIZE_UNIT (decl
) != 0
439 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
440 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
442 /* If requested, warn about definitions of large data objects. */
444 && (code
== VAR_DECL
|| code
== PARM_DECL
)
445 && ! DECL_EXTERNAL (decl
))
447 tree size
= DECL_SIZE_UNIT (decl
);
449 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
450 && compare_tree_int (size
, larger_than_size
) > 0)
452 int size_as_int
= TREE_INT_CST_LOW (size
);
454 if (compare_tree_int (size
, size_as_int
) == 0)
455 warning (0, "size of %q+D is %d bytes", decl
, size_as_int
);
457 warning (0, "size of %q+D is larger than %wd bytes",
458 decl
, larger_than_size
);
462 /* If the RTL was already set, update its mode and mem attributes. */
465 PUT_MODE (rtl
, DECL_MODE (decl
));
466 SET_DECL_RTL (decl
, 0);
467 set_mem_attributes (rtl
, decl
, 1);
468 SET_DECL_RTL (decl
, rtl
);
472 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
473 a previous call to layout_decl and calls it again. */
476 relayout_decl (tree decl
)
478 DECL_SIZE (decl
) = DECL_SIZE_UNIT (decl
) = 0;
479 DECL_MODE (decl
) = VOIDmode
;
480 DECL_ALIGN (decl
) = 0;
481 SET_DECL_RTL (decl
, 0);
483 layout_decl (decl
, 0);
486 /* Hook for a front-end function that can modify the record layout as needed
487 immediately before it is finalized. */
489 static void (*lang_adjust_rli
) (record_layout_info
) = 0;
492 set_lang_adjust_rli (void (*f
) (record_layout_info
))
497 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
498 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
499 is to be passed to all other layout functions for this record. It is the
500 responsibility of the caller to call `free' for the storage returned.
501 Note that garbage collection is not permitted until we finish laying
505 start_record_layout (tree t
)
507 record_layout_info rli
= xmalloc (sizeof (struct record_layout_info_s
));
511 /* If the type has a minimum specified alignment (via an attribute
512 declaration, for example) use it -- otherwise, start with a
513 one-byte alignment. */
514 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
515 rli
->unpacked_align
= rli
->record_align
;
516 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
518 #ifdef STRUCTURE_SIZE_BOUNDARY
519 /* Packed structures don't need to have minimum size. */
520 if (! TYPE_PACKED (t
))
521 rli
->record_align
= MAX (rli
->record_align
, (unsigned) STRUCTURE_SIZE_BOUNDARY
);
524 rli
->offset
= size_zero_node
;
525 rli
->bitpos
= bitsize_zero_node
;
527 rli
->pending_statics
= 0;
528 rli
->packed_maybe_necessary
= 0;
533 /* These four routines perform computations that convert between
534 the offset/bitpos forms and byte and bit offsets. */
537 bit_from_pos (tree offset
, tree bitpos
)
539 return size_binop (PLUS_EXPR
, bitpos
,
540 size_binop (MULT_EXPR
,
541 fold_convert (bitsizetype
, offset
),
546 byte_from_pos (tree offset
, tree bitpos
)
548 return size_binop (PLUS_EXPR
, offset
,
549 fold_convert (sizetype
,
550 size_binop (TRUNC_DIV_EXPR
, bitpos
,
551 bitsize_unit_node
)));
555 pos_from_bit (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
,
558 *poffset
= size_binop (MULT_EXPR
,
559 fold_convert (sizetype
,
560 size_binop (FLOOR_DIV_EXPR
, pos
,
561 bitsize_int (off_align
))),
562 size_int (off_align
/ BITS_PER_UNIT
));
563 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
566 /* Given a pointer to bit and byte offsets and an offset alignment,
567 normalize the offsets so they are within the alignment. */
570 normalize_offset (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
)
572 /* If the bit position is now larger than it should be, adjust it
574 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
576 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
577 bitsize_int (off_align
));
580 = size_binop (PLUS_EXPR
, *poffset
,
581 size_binop (MULT_EXPR
,
582 fold_convert (sizetype
, extra_aligns
),
583 size_int (off_align
/ BITS_PER_UNIT
)));
586 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
590 /* Print debugging information about the information in RLI. */
593 debug_rli (record_layout_info rli
)
595 print_node_brief (stderr
, "type", rli
->t
, 0);
596 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
597 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
599 fprintf (stderr
, "\naligns: rec = %u, unpack = %u, off = %u\n",
600 rli
->record_align
, rli
->unpacked_align
,
602 if (rli
->packed_maybe_necessary
)
603 fprintf (stderr
, "packed may be necessary\n");
605 if (rli
->pending_statics
)
607 fprintf (stderr
, "pending statics:\n");
608 debug_tree (rli
->pending_statics
);
612 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
613 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
616 normalize_rli (record_layout_info rli
)
618 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
621 /* Returns the size in bytes allocated so far. */
624 rli_size_unit_so_far (record_layout_info rli
)
626 return byte_from_pos (rli
->offset
, rli
->bitpos
);
629 /* Returns the size in bits allocated so far. */
632 rli_size_so_far (record_layout_info rli
)
634 return bit_from_pos (rli
->offset
, rli
->bitpos
);
637 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
638 the next available location within the record is given by KNOWN_ALIGN.
639 Update the variable alignment fields in RLI, and return the alignment
640 to give the FIELD. */
643 update_alignment_for_field (record_layout_info rli
, tree field
,
644 unsigned int known_align
)
646 /* The alignment required for FIELD. */
647 unsigned int desired_align
;
648 /* The type of this field. */
649 tree type
= TREE_TYPE (field
);
650 /* True if the field was explicitly aligned by the user. */
654 /* Lay out the field so we know what alignment it needs. */
655 layout_decl (field
, known_align
);
656 desired_align
= DECL_ALIGN (field
);
657 user_align
= DECL_USER_ALIGN (field
);
659 is_bitfield
= (type
!= error_mark_node
660 && DECL_BIT_FIELD_TYPE (field
)
661 && ! integer_zerop (TYPE_SIZE (type
)));
663 /* Record must have at least as much alignment as any field.
664 Otherwise, the alignment of the field within the record is
666 if (is_bitfield
&& targetm
.ms_bitfield_layout_p (rli
->t
))
668 /* Here, the alignment of the underlying type of a bitfield can
669 affect the alignment of a record; even a zero-sized field
670 can do this. The alignment should be to the alignment of
671 the type, except that for zero-size bitfields this only
672 applies if there was an immediately prior, nonzero-size
673 bitfield. (That's the way it is, experimentally.) */
674 if (! integer_zerop (DECL_SIZE (field
))
675 ? ! DECL_PACKED (field
)
677 && DECL_BIT_FIELD_TYPE (rli
->prev_field
)
678 && ! integer_zerop (DECL_SIZE (rli
->prev_field
))))
680 unsigned int type_align
= TYPE_ALIGN (type
);
681 type_align
= MAX (type_align
, desired_align
);
682 if (maximum_field_alignment
!= 0)
683 type_align
= MIN (type_align
, maximum_field_alignment
);
684 rli
->record_align
= MAX (rli
->record_align
, type_align
);
685 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
686 /* If we start a new run, make sure we start it properly aligned. */
687 if ((!rli
->prev_field
688 || integer_zerop (DECL_SIZE (field
))
689 || integer_zerop (DECL_SIZE (rli
->prev_field
))
690 || !host_integerp (DECL_SIZE (rli
->prev_field
), 0)
691 || !host_integerp (TYPE_SIZE (type
), 0)
692 || !simple_cst_equal (TYPE_SIZE (type
),
693 TYPE_SIZE (TREE_TYPE (rli
->prev_field
)))
694 || (rli
->remaining_in_alignment
695 < tree_low_cst (DECL_SIZE (field
), 0)))
696 && desired_align
< type_align
)
697 desired_align
= type_align
;
700 #ifdef PCC_BITFIELD_TYPE_MATTERS
701 else if (is_bitfield
&& PCC_BITFIELD_TYPE_MATTERS
)
703 /* Named bit-fields cause the entire structure to have the
704 alignment implied by their type. Some targets also apply the same
705 rules to unnamed bitfields. */
706 if (DECL_NAME (field
) != 0
707 || targetm
.align_anon_bitfield ())
709 unsigned int type_align
= TYPE_ALIGN (type
);
711 #ifdef ADJUST_FIELD_ALIGN
712 if (! TYPE_USER_ALIGN (type
))
713 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
716 if (maximum_field_alignment
!= 0)
717 type_align
= MIN (type_align
, maximum_field_alignment
);
718 else if (DECL_PACKED (field
))
719 type_align
= MIN (type_align
, BITS_PER_UNIT
);
721 /* The alignment of the record is increased to the maximum
722 of the current alignment, the alignment indicated on the
723 field (i.e., the alignment specified by an __aligned__
724 attribute), and the alignment indicated by the type of
726 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
727 rli
->record_align
= MAX (rli
->record_align
, type_align
);
730 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
731 user_align
|= TYPE_USER_ALIGN (type
);
737 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
738 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
741 TYPE_USER_ALIGN (rli
->t
) |= user_align
;
743 return desired_align
;
746 /* Called from place_field to handle unions. */
749 place_union_field (record_layout_info rli
, tree field
)
751 update_alignment_for_field (rli
, field
, /*known_align=*/0);
753 DECL_FIELD_OFFSET (field
) = size_zero_node
;
754 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
755 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
757 /* We assume the union's size will be a multiple of a byte so we don't
758 bother with BITPOS. */
759 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
760 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
761 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
762 rli
->offset
= fold_build3 (COND_EXPR
, sizetype
,
763 DECL_QUALIFIER (field
),
764 DECL_SIZE_UNIT (field
), rli
->offset
);
767 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
768 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
769 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
770 units of alignment than the underlying TYPE. */
772 excess_unit_span (HOST_WIDE_INT byte_offset
, HOST_WIDE_INT bit_offset
,
773 HOST_WIDE_INT size
, HOST_WIDE_INT align
, tree type
)
775 /* Note that the calculation of OFFSET might overflow; we calculate it so
776 that we still get the right result as long as ALIGN is a power of two. */
777 unsigned HOST_WIDE_INT offset
= byte_offset
* BITS_PER_UNIT
+ bit_offset
;
779 offset
= offset
% align
;
780 return ((offset
+ size
+ align
- 1) / align
781 > ((unsigned HOST_WIDE_INT
) tree_low_cst (TYPE_SIZE (type
), 1)
786 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
787 is a FIELD_DECL to be added after those fields already present in
788 T. (FIELD is not actually added to the TYPE_FIELDS list here;
789 callers that desire that behavior must manually perform that step.) */
792 place_field (record_layout_info rli
, tree field
)
794 /* The alignment required for FIELD. */
795 unsigned int desired_align
;
796 /* The alignment FIELD would have if we just dropped it into the
797 record as it presently stands. */
798 unsigned int known_align
;
799 unsigned int actual_align
;
800 /* The type of this field. */
801 tree type
= TREE_TYPE (field
);
803 if (TREE_CODE (field
) == ERROR_MARK
|| TREE_CODE (type
) == ERROR_MARK
)
806 /* If FIELD is static, then treat it like a separate variable, not
807 really like a structure field. If it is a FUNCTION_DECL, it's a
808 method. In both cases, all we do is lay out the decl, and we do
809 it *after* the record is laid out. */
810 if (TREE_CODE (field
) == VAR_DECL
)
812 rli
->pending_statics
= tree_cons (NULL_TREE
, field
,
813 rli
->pending_statics
);
817 /* Enumerators and enum types which are local to this class need not
818 be laid out. Likewise for initialized constant fields. */
819 else if (TREE_CODE (field
) != FIELD_DECL
)
822 /* Unions are laid out very differently than records, so split
823 that code off to another function. */
824 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
826 place_union_field (rli
, field
);
830 /* Work out the known alignment so far. Note that A & (-A) is the
831 value of the least-significant bit in A that is one. */
832 if (! integer_zerop (rli
->bitpos
))
833 known_align
= (tree_low_cst (rli
->bitpos
, 1)
834 & - tree_low_cst (rli
->bitpos
, 1));
835 else if (integer_zerop (rli
->offset
))
837 else if (host_integerp (rli
->offset
, 1))
838 known_align
= (BITS_PER_UNIT
839 * (tree_low_cst (rli
->offset
, 1)
840 & - tree_low_cst (rli
->offset
, 1)));
842 known_align
= rli
->offset_align
;
844 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
845 if (known_align
== 0)
846 known_align
= MAX (BIGGEST_ALIGNMENT
, rli
->record_align
);
848 if (warn_packed
&& DECL_PACKED (field
))
850 if (known_align
>= TYPE_ALIGN (type
))
852 if (TYPE_ALIGN (type
) > desired_align
)
854 if (STRICT_ALIGNMENT
)
855 warning (OPT_Wattributes
, "packed attribute causes "
856 "inefficient alignment for %q+D", field
);
858 warning (OPT_Wattributes
, "packed attribute is "
859 "unnecessary for %q+D", field
);
863 rli
->packed_maybe_necessary
= 1;
866 /* Does this field automatically have alignment it needs by virtue
867 of the fields that precede it and the record's own alignment? */
868 if (known_align
< desired_align
)
870 /* No, we need to skip space before this field.
871 Bump the cumulative size to multiple of field alignment. */
873 warning (OPT_Wpadded
, "padding struct to align %q+D", field
);
875 /* If the alignment is still within offset_align, just align
877 if (desired_align
< rli
->offset_align
)
878 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
881 /* First adjust OFFSET by the partial bits, then align. */
883 = size_binop (PLUS_EXPR
, rli
->offset
,
884 fold_convert (sizetype
,
885 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
886 bitsize_unit_node
)));
887 rli
->bitpos
= bitsize_zero_node
;
889 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
892 if (! TREE_CONSTANT (rli
->offset
))
893 rli
->offset_align
= desired_align
;
897 /* Handle compatibility with PCC. Note that if the record has any
898 variable-sized fields, we need not worry about compatibility. */
899 #ifdef PCC_BITFIELD_TYPE_MATTERS
900 if (PCC_BITFIELD_TYPE_MATTERS
901 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
902 && TREE_CODE (field
) == FIELD_DECL
903 && type
!= error_mark_node
904 && DECL_BIT_FIELD (field
)
905 && ! DECL_PACKED (field
)
906 && maximum_field_alignment
== 0
907 && ! integer_zerop (DECL_SIZE (field
))
908 && host_integerp (DECL_SIZE (field
), 1)
909 && host_integerp (rli
->offset
, 1)
910 && host_integerp (TYPE_SIZE (type
), 1))
912 unsigned int type_align
= TYPE_ALIGN (type
);
913 tree dsize
= DECL_SIZE (field
);
914 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
915 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
916 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
918 #ifdef ADJUST_FIELD_ALIGN
919 if (! TYPE_USER_ALIGN (type
))
920 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
923 /* A bit field may not span more units of alignment of its type
924 than its type itself. Advance to next boundary if necessary. */
925 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
926 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
928 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
932 #ifdef BITFIELD_NBYTES_LIMITED
933 if (BITFIELD_NBYTES_LIMITED
934 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
935 && TREE_CODE (field
) == FIELD_DECL
936 && type
!= error_mark_node
937 && DECL_BIT_FIELD_TYPE (field
)
938 && ! DECL_PACKED (field
)
939 && ! integer_zerop (DECL_SIZE (field
))
940 && host_integerp (DECL_SIZE (field
), 1)
941 && host_integerp (rli
->offset
, 1)
942 && host_integerp (TYPE_SIZE (type
), 1))
944 unsigned int type_align
= TYPE_ALIGN (type
);
945 tree dsize
= DECL_SIZE (field
);
946 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
947 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
948 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
950 #ifdef ADJUST_FIELD_ALIGN
951 if (! TYPE_USER_ALIGN (type
))
952 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
955 if (maximum_field_alignment
!= 0)
956 type_align
= MIN (type_align
, maximum_field_alignment
);
957 /* ??? This test is opposite the test in the containing if
958 statement, so this code is unreachable currently. */
959 else if (DECL_PACKED (field
))
960 type_align
= MIN (type_align
, BITS_PER_UNIT
);
962 /* A bit field may not span the unit of alignment of its type.
963 Advance to next boundary if necessary. */
964 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
965 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
967 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
971 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
973 When a bit field is inserted into a packed record, the whole
974 size of the underlying type is used by one or more same-size
975 adjacent bitfields. (That is, if its long:3, 32 bits is
976 used in the record, and any additional adjacent long bitfields are
977 packed into the same chunk of 32 bits. However, if the size
978 changes, a new field of that size is allocated.) In an unpacked
979 record, this is the same as using alignment, but not equivalent
982 Note: for compatibility, we use the type size, not the type alignment
983 to determine alignment, since that matches the documentation */
985 if (targetm
.ms_bitfield_layout_p (rli
->t
)
986 && ((DECL_BIT_FIELD_TYPE (field
) && ! DECL_PACKED (field
))
987 || (rli
->prev_field
&& ! DECL_PACKED (rli
->prev_field
))))
989 /* At this point, either the prior or current are bitfields,
990 (possibly both), and we're dealing with MS packing. */
991 tree prev_saved
= rli
->prev_field
;
993 /* Is the prior field a bitfield? If so, handle "runs" of same
995 if (rli
->prev_field
/* necessarily a bitfield if it exists. */)
997 /* If both are bitfields, nonzero, and the same size, this is
998 the middle of a run. Zero declared size fields are special
999 and handled as "end of run". (Note: it's nonzero declared
1000 size, but equal type sizes!) (Since we know that both
1001 the current and previous fields are bitfields by the
1002 time we check it, DECL_SIZE must be present for both.) */
1003 if (DECL_BIT_FIELD_TYPE (field
)
1004 && !integer_zerop (DECL_SIZE (field
))
1005 && !integer_zerop (DECL_SIZE (rli
->prev_field
))
1006 && host_integerp (DECL_SIZE (rli
->prev_field
), 0)
1007 && host_integerp (TYPE_SIZE (type
), 0)
1008 && simple_cst_equal (TYPE_SIZE (type
),
1009 TYPE_SIZE (TREE_TYPE (rli
->prev_field
))))
1011 /* We're in the middle of a run of equal type size fields; make
1012 sure we realign if we run out of bits. (Not decl size,
1014 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 0);
1016 if (rli
->remaining_in_alignment
< bitsize
)
1018 /* If PREV_FIELD is packed, and we haven't lumped
1019 non-packed bitfields with it, treat this as if PREV_FIELD
1020 was not a bitfield. This avoids anomalies where a packed
1021 bitfield with long long base type can take up more
1022 space than a same-size bitfield with base type short. */
1023 if (rli
->prev_packed
)
1024 rli
->prev_field
= prev_saved
= NULL
;
1027 /* out of bits; bump up to next 'word'. */
1028 rli
->offset
= DECL_FIELD_OFFSET (rli
->prev_field
);
1030 = size_binop (PLUS_EXPR
, TYPE_SIZE (type
),
1031 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1032 rli
->prev_field
= field
;
1033 rli
->remaining_in_alignment
1034 = tree_low_cst (TYPE_SIZE (type
), 0) - bitsize
;
1038 rli
->remaining_in_alignment
-= bitsize
;
1040 else if (rli
->prev_packed
)
1041 rli
->prev_field
= prev_saved
= NULL
;
1044 /* End of a run: if leaving a run of bitfields of the same type
1045 size, we have to "use up" the rest of the bits of the type
1048 Compute the new position as the sum of the size for the prior
1049 type and where we first started working on that type.
1050 Note: since the beginning of the field was aligned then
1051 of course the end will be too. No round needed. */
1053 if (!integer_zerop (DECL_SIZE (rli
->prev_field
)))
1055 tree type_size
= TYPE_SIZE (TREE_TYPE (rli
->prev_field
));
1057 /* If the desired alignment is greater or equal to TYPE_SIZE,
1058 we have already adjusted rli->bitpos / rli->offset above.
1060 if ((unsigned HOST_WIDE_INT
) tree_low_cst (type_size
, 0)
1063 = size_binop (PLUS_EXPR
, type_size
,
1064 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1067 /* We "use up" size zero fields; the code below should behave
1068 as if the prior field was not a bitfield. */
1071 /* Cause a new bitfield to be captured, either this time (if
1072 currently a bitfield) or next time we see one. */
1073 if (!DECL_BIT_FIELD_TYPE(field
)
1074 || integer_zerop (DECL_SIZE (field
)))
1075 rli
->prev_field
= NULL
;
1078 rli
->prev_packed
= 0;
1079 normalize_rli (rli
);
1082 /* If we're starting a new run of same size type bitfields
1083 (or a run of non-bitfields), set up the "first of the run"
1086 That is, if the current field is not a bitfield, or if there
1087 was a prior bitfield the type sizes differ, or if there wasn't
1088 a prior bitfield the size of the current field is nonzero.
1090 Note: we must be sure to test ONLY the type size if there was
1091 a prior bitfield and ONLY for the current field being zero if
1094 if (!DECL_BIT_FIELD_TYPE (field
)
1095 || ( prev_saved
!= NULL
1096 ? !simple_cst_equal (TYPE_SIZE (type
),
1097 TYPE_SIZE (TREE_TYPE (prev_saved
)))
1098 : !integer_zerop (DECL_SIZE (field
)) ))
1100 /* Never smaller than a byte for compatibility. */
1101 unsigned int type_align
= BITS_PER_UNIT
;
1103 /* (When not a bitfield), we could be seeing a flex array (with
1104 no DECL_SIZE). Since we won't be using remaining_in_alignment
1105 until we see a bitfield (and come by here again) we just skip
1107 if (DECL_SIZE (field
) != NULL
1108 && host_integerp (TYPE_SIZE (TREE_TYPE (field
)), 0)
1109 && host_integerp (DECL_SIZE (field
), 0))
1110 rli
->remaining_in_alignment
1111 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field
)), 0)
1112 - tree_low_cst (DECL_SIZE (field
), 0);
1114 /* Now align (conventionally) for the new type. */
1115 if (!DECL_PACKED(field
))
1116 type_align
= MAX(TYPE_ALIGN (type
), type_align
);
1119 && DECL_BIT_FIELD_TYPE (prev_saved
)
1120 /* If the previous bit-field is zero-sized, we've already
1121 accounted for its alignment needs (or ignored it, if
1122 appropriate) while placing it. */
1123 && ! integer_zerop (DECL_SIZE (prev_saved
)))
1124 type_align
= MAX (type_align
,
1125 TYPE_ALIGN (TREE_TYPE (prev_saved
)));
1127 if (maximum_field_alignment
!= 0)
1128 type_align
= MIN (type_align
, maximum_field_alignment
);
1130 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1132 /* If we really aligned, don't allow subsequent bitfields
1134 rli
->prev_field
= NULL
;
1138 /* Offset so far becomes the position of this field after normalizing. */
1139 normalize_rli (rli
);
1140 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1141 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1142 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1144 /* If this field ended up more aligned than we thought it would be (we
1145 approximate this by seeing if its position changed), lay out the field
1146 again; perhaps we can use an integral mode for it now. */
1147 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
1148 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
1149 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
1150 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
1151 actual_align
= MAX (BIGGEST_ALIGNMENT
, rli
->record_align
);
1152 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
1153 actual_align
= (BITS_PER_UNIT
1154 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
1155 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
1157 actual_align
= DECL_OFFSET_ALIGN (field
);
1158 /* ACTUAL_ALIGN is still the actual alignment *within the record* .
1159 store / extract bit field operations will check the alignment of the
1160 record against the mode of bit fields. */
1162 if (known_align
!= actual_align
)
1163 layout_decl (field
, actual_align
);
1165 if (DECL_BIT_FIELD_TYPE (field
))
1167 unsigned int type_align
= TYPE_ALIGN (type
);
1169 /* Only the MS bitfields use this. We used to also put any kind of
1170 packed bit fields into prev_field, but that makes no sense, because
1171 an 8 bit packed bit field shouldn't impose more restriction on
1172 following fields than a char field, and the alignment requirements
1173 are also not fulfilled.
1174 There is no sane value to set rli->remaining_in_alignment to when
1175 a packed bitfield in prev_field is unaligned. */
1176 if (maximum_field_alignment
!= 0)
1177 type_align
= MIN (type_align
, maximum_field_alignment
);
1178 gcc_assert (rli
->prev_field
1179 || actual_align
>= type_align
|| DECL_PACKED (field
)
1180 || integer_zerop (DECL_SIZE (field
))
1181 || !targetm
.ms_bitfield_layout_p (rli
->t
));
1182 if (rli
->prev_field
== NULL
&& actual_align
>= type_align
1183 && !integer_zerop (DECL_SIZE (field
)))
1185 rli
->prev_field
= field
;
1186 /* rli->remaining_in_alignment has not been set if the bitfield
1187 has size zero, or if it is a packed bitfield. */
1188 rli
->remaining_in_alignment
1189 = (tree_low_cst (TYPE_SIZE (TREE_TYPE (field
)), 0)
1190 - tree_low_cst (DECL_SIZE (field
), 0));
1191 rli
->prev_packed
= DECL_PACKED (field
);
1194 else if (rli
->prev_field
&& DECL_PACKED (field
))
1196 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 0);
1198 if (rli
->remaining_in_alignment
< bitsize
)
1199 rli
->prev_field
= NULL
;
1201 rli
->remaining_in_alignment
-= bitsize
;
1205 /* Now add size of this field to the size of the record. If the size is
1206 not constant, treat the field as being a multiple of bytes and just
1207 adjust the offset, resetting the bit position. Otherwise, apportion the
1208 size amongst the bit position and offset. First handle the case of an
1209 unspecified size, which can happen when we have an invalid nested struct
1210 definition, such as struct j { struct j { int i; } }. The error message
1211 is printed in finish_struct. */
1212 if (DECL_SIZE (field
) == 0)
1214 else if (TREE_CODE (DECL_SIZE_UNIT (field
)) != INTEGER_CST
1215 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field
)))
1218 = size_binop (PLUS_EXPR
, rli
->offset
,
1219 fold_convert (sizetype
,
1220 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1221 bitsize_unit_node
)));
1223 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1224 rli
->bitpos
= bitsize_zero_node
;
1225 rli
->offset_align
= MIN (rli
->offset_align
, desired_align
);
1229 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1230 normalize_rli (rli
);
1234 /* Assuming that all the fields have been laid out, this function uses
1235 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1236 indicated by RLI. */
1239 finalize_record_size (record_layout_info rli
)
1241 tree unpadded_size
, unpadded_size_unit
;
1243 /* Now we want just byte and bit offsets, so set the offset alignment
1244 to be a byte and then normalize. */
1245 rli
->offset_align
= BITS_PER_UNIT
;
1246 normalize_rli (rli
);
1248 /* Determine the desired alignment. */
1249 #ifdef ROUND_TYPE_ALIGN
1250 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
1253 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
1256 /* Compute the size so far. Be sure to allow for extra bits in the
1257 size in bytes. We have guaranteed above that it will be no more
1258 than a single byte. */
1259 unpadded_size
= rli_size_so_far (rli
);
1260 unpadded_size_unit
= rli_size_unit_so_far (rli
);
1261 if (! integer_zerop (rli
->bitpos
))
1263 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
1265 /* Round the size up to be a multiple of the required alignment. */
1266 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
1267 TYPE_SIZE_UNIT (rli
->t
)
1268 = round_up (unpadded_size_unit
, TYPE_ALIGN_UNIT (rli
->t
));
1270 if (TREE_CONSTANT (unpadded_size
)
1271 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0)
1272 warning (OPT_Wpadded
, "padding struct size to alignment boundary");
1274 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
1275 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
1276 && TREE_CONSTANT (unpadded_size
))
1280 #ifdef ROUND_TYPE_ALIGN
1282 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1284 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1287 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
1288 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
1290 TYPE_PACKED (rli
->t
) = 0;
1292 if (TYPE_NAME (rli
->t
))
1296 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1297 name
= IDENTIFIER_POINTER (TYPE_NAME (rli
->t
));
1299 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli
->t
)));
1301 if (STRICT_ALIGNMENT
)
1302 warning (OPT_Wpacked
, "packed attribute causes inefficient "
1303 "alignment for %qs", name
);
1305 warning (OPT_Wpacked
,
1306 "packed attribute is unnecessary for %qs", name
);
1310 if (STRICT_ALIGNMENT
)
1311 warning (OPT_Wpacked
,
1312 "packed attribute causes inefficient alignment");
1314 warning (OPT_Wpacked
, "packed attribute is unnecessary");
1320 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1323 compute_record_mode (tree type
)
1326 enum machine_mode mode
= VOIDmode
;
1328 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1329 However, if possible, we use a mode that fits in a register
1330 instead, in order to allow for better optimization down the
1332 TYPE_MODE (type
) = BLKmode
;
1334 if (! host_integerp (TYPE_SIZE (type
), 1))
1337 /* A record which has any BLKmode members must itself be
1338 BLKmode; it can't go in a register. Unless the member is
1339 BLKmode only because it isn't aligned. */
1340 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1342 if (TREE_CODE (field
) != FIELD_DECL
)
1345 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1346 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1347 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
))
1348 && !(TYPE_SIZE (TREE_TYPE (field
)) != 0
1349 && integer_zerop (TYPE_SIZE (TREE_TYPE (field
)))))
1350 || ! host_integerp (bit_position (field
), 1)
1351 || DECL_SIZE (field
) == 0
1352 || ! host_integerp (DECL_SIZE (field
), 1))
1355 /* If this field is the whole struct, remember its mode so
1356 that, say, we can put a double in a class into a DF
1357 register instead of forcing it to live in the stack. */
1358 if (simple_cst_equal (TYPE_SIZE (type
), DECL_SIZE (field
)))
1359 mode
= DECL_MODE (field
);
1361 #ifdef MEMBER_TYPE_FORCES_BLK
1362 /* With some targets, eg. c4x, it is sub-optimal
1363 to access an aligned BLKmode structure as a scalar. */
1365 if (MEMBER_TYPE_FORCES_BLK (field
, mode
))
1367 #endif /* MEMBER_TYPE_FORCES_BLK */
1370 TYPE_MODE (type
) = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1372 /* If we only have one real field; use its mode if that mode's size
1373 matches the type's size. This only applies to RECORD_TYPE. This
1374 does not apply to unions. */
1375 if (TREE_CODE (type
) == RECORD_TYPE
&& mode
!= VOIDmode
1376 && GET_MODE_SIZE (mode
) == GET_MODE_SIZE (TYPE_MODE (type
)))
1377 TYPE_MODE (type
) = mode
;
1379 /* If structure's known alignment is less than what the scalar
1380 mode would need, and it matters, then stick with BLKmode. */
1381 if (TYPE_MODE (type
) != BLKmode
1383 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1384 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1386 /* If this is the only reason this type is BLKmode, then
1387 don't force containing types to be BLKmode. */
1388 TYPE_NO_FORCE_BLK (type
) = 1;
1389 TYPE_MODE (type
) = BLKmode
;
1393 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1397 finalize_type_size (tree type
)
1399 /* Normally, use the alignment corresponding to the mode chosen.
1400 However, where strict alignment is not required, avoid
1401 over-aligning structures, since most compilers do not do this
1402 alignment. Also, we must avoid overriding a larger alignment
1403 requirement coming from a user alignment of one of the fields. */
1404 /* ??? The non-aggregate code is also needed to reduce the alignment
1405 of java types with alignment less than 16 bits. The problem stems
1406 from java/decl.c using char_type_node for the 16 bit character type,
1407 while tree.c:make_node uses it as the type of the smallest addressable
1408 unit to initialize the alignment of all types. */
1409 unsigned mode_align
= GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1411 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1412 && ((STRICT_ALIGNMENT
&& mode_align
>= TYPE_ALIGN (type
))
1413 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1414 && TREE_CODE (type
) != QUAL_UNION_TYPE
1415 && TREE_CODE (type
) != ARRAY_TYPE
)))
1417 TYPE_ALIGN (type
) = mode_align
;
1418 TYPE_USER_ALIGN (type
) = 0;
1421 /* Do machine-dependent extra alignment. */
1422 #ifdef ROUND_TYPE_ALIGN
1424 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1427 /* If we failed to find a simple way to calculate the unit size
1428 of the type, find it by division. */
1429 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1430 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1431 result will fit in sizetype. We will get more efficient code using
1432 sizetype, so we force a conversion. */
1433 TYPE_SIZE_UNIT (type
)
1434 = fold_convert (sizetype
,
1435 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1436 bitsize_unit_node
));
1438 if (TYPE_SIZE (type
) != 0)
1440 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1441 TYPE_SIZE_UNIT (type
) = round_up (TYPE_SIZE_UNIT (type
),
1442 TYPE_ALIGN_UNIT (type
));
1445 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1446 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1447 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1448 if (TYPE_SIZE_UNIT (type
) != 0
1449 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1450 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1452 /* Also layout any other variants of the type. */
1453 if (TYPE_NEXT_VARIANT (type
)
1454 || type
!= TYPE_MAIN_VARIANT (type
))
1457 /* Record layout info of this variant. */
1458 tree size
= TYPE_SIZE (type
);
1459 tree size_unit
= TYPE_SIZE_UNIT (type
);
1460 unsigned int align
= TYPE_ALIGN (type
);
1461 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1462 enum machine_mode mode
= TYPE_MODE (type
);
1464 /* Copy it into all variants. */
1465 for (variant
= TYPE_MAIN_VARIANT (type
);
1467 variant
= TYPE_NEXT_VARIANT (variant
))
1469 TYPE_SIZE (variant
) = size
;
1470 TYPE_SIZE_UNIT (variant
) = size_unit
;
1471 TYPE_ALIGN (variant
) = align
;
1472 TYPE_USER_ALIGN (variant
) = user_align
;
1473 TYPE_MODE (variant
) = mode
;
1478 /* Do all of the work required to layout the type indicated by RLI,
1479 once the fields have been laid out. This function will call `free'
1480 for RLI, unless FREE_P is false. Passing a value other than false
1481 for FREE_P is bad practice; this option only exists to support the
1485 finish_record_layout (record_layout_info rli
, int free_p
)
1489 /* Compute the final size. */
1490 finalize_record_size (rli
);
1492 /* Compute the TYPE_MODE for the record. */
1493 compute_record_mode (rli
->t
);
1495 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1496 finalize_type_size (rli
->t
);
1498 /* We might be able to clear DECL_PACKED on any members that happen
1499 to be suitably aligned (not forgetting the alignment of the type
1501 for (field
= TYPE_FIELDS (rli
->t
); field
; field
= TREE_CHAIN (field
))
1502 if (TREE_CODE (field
) == FIELD_DECL
&& DECL_PACKED (field
)
1503 && DECL_OFFSET_ALIGN (field
) >= TYPE_ALIGN (TREE_TYPE (field
))
1504 && TYPE_ALIGN (rli
->t
) >= TYPE_ALIGN (TREE_TYPE (field
)))
1505 DECL_PACKED (field
) = 0;
1507 /* Lay out any static members. This is done now because their type
1508 may use the record's type. */
1509 while (rli
->pending_statics
)
1511 layout_decl (TREE_VALUE (rli
->pending_statics
), 0);
1512 rli
->pending_statics
= TREE_CHAIN (rli
->pending_statics
);
1521 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1522 NAME, its fields are chained in reverse on FIELDS.
1524 If ALIGN_TYPE is non-null, it is given the same alignment as
1528 finish_builtin_struct (tree type
, const char *name
, tree fields
,
1533 for (tail
= NULL_TREE
; fields
; tail
= fields
, fields
= next
)
1535 DECL_FIELD_CONTEXT (fields
) = type
;
1536 next
= TREE_CHAIN (fields
);
1537 TREE_CHAIN (fields
) = tail
;
1539 TYPE_FIELDS (type
) = tail
;
1543 TYPE_ALIGN (type
) = TYPE_ALIGN (align_type
);
1544 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (align_type
);
1548 #if 0 /* not yet, should get fixed properly later */
1549 TYPE_NAME (type
) = make_type_decl (get_identifier (name
), type
);
1551 TYPE_NAME (type
) = build_decl (TYPE_DECL
, get_identifier (name
), type
);
1553 TYPE_STUB_DECL (type
) = TYPE_NAME (type
);
1554 layout_decl (TYPE_NAME (type
), 0);
1557 /* Calculate the mode, size, and alignment for TYPE.
1558 For an array type, calculate the element separation as well.
1559 Record TYPE on the chain of permanent or temporary types
1560 so that dbxout will find out about it.
1562 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1563 layout_type does nothing on such a type.
1565 If the type is incomplete, its TYPE_SIZE remains zero. */
1568 layout_type (tree type
)
1572 if (type
== error_mark_node
)
1575 /* Do nothing if type has been laid out before. */
1576 if (TYPE_SIZE (type
))
1579 switch (TREE_CODE (type
))
1582 /* This kind of type is the responsibility
1583 of the language-specific code. */
1586 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1587 if (TYPE_PRECISION (type
) == 0)
1588 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1590 /* ... fall through ... */
1595 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1596 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1597 TYPE_UNSIGNED (type
) = 1;
1599 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
1601 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1602 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1606 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
1607 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1608 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1612 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1614 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1615 (TREE_CODE (TREE_TYPE (type
)) == REAL_TYPE
1616 ? MODE_COMPLEX_FLOAT
: MODE_COMPLEX_INT
),
1618 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1619 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1624 int nunits
= TYPE_VECTOR_SUBPARTS (type
);
1625 tree nunits_tree
= build_int_cst (NULL_TREE
, nunits
);
1626 tree innertype
= TREE_TYPE (type
);
1628 gcc_assert (!(nunits
& (nunits
- 1)));
1630 /* Find an appropriate mode for the vector type. */
1631 if (TYPE_MODE (type
) == VOIDmode
)
1633 enum machine_mode innermode
= TYPE_MODE (innertype
);
1634 enum machine_mode mode
;
1636 /* First, look for a supported vector type. */
1637 if (GET_MODE_CLASS (innermode
) == MODE_FLOAT
)
1638 mode
= MIN_MODE_VECTOR_FLOAT
;
1640 mode
= MIN_MODE_VECTOR_INT
;
1642 for (; mode
!= VOIDmode
; mode
= GET_MODE_WIDER_MODE (mode
))
1643 if (GET_MODE_NUNITS (mode
) == nunits
1644 && GET_MODE_INNER (mode
) == innermode
1645 && targetm
.vector_mode_supported_p (mode
))
1648 /* For integers, try mapping it to a same-sized scalar mode. */
1649 if (mode
== VOIDmode
1650 && GET_MODE_CLASS (innermode
) == MODE_INT
)
1651 mode
= mode_for_size (nunits
* GET_MODE_BITSIZE (innermode
),
1654 if (mode
== VOIDmode
|| !have_regs_of_mode
[mode
])
1655 TYPE_MODE (type
) = BLKmode
;
1657 TYPE_MODE (type
) = mode
;
1660 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1661 TYPE_SIZE_UNIT (type
) = int_const_binop (MULT_EXPR
,
1662 TYPE_SIZE_UNIT (innertype
),
1664 TYPE_SIZE (type
) = int_const_binop (MULT_EXPR
, TYPE_SIZE (innertype
),
1667 /* Always naturally align vectors. This prevents ABI changes
1668 depending on whether or not native vector modes are supported. */
1669 TYPE_ALIGN (type
) = tree_low_cst (TYPE_SIZE (type
), 0);
1674 /* This is an incomplete type and so doesn't have a size. */
1675 TYPE_ALIGN (type
) = 1;
1676 TYPE_USER_ALIGN (type
) = 0;
1677 TYPE_MODE (type
) = VOIDmode
;
1681 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1682 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1683 /* A pointer might be MODE_PARTIAL_INT,
1684 but ptrdiff_t must be integral. */
1685 TYPE_MODE (type
) = mode_for_size (POINTER_SIZE
, MODE_INT
, 0);
1690 /* It's hard to see what the mode and size of a function ought to
1691 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1692 make it consistent with that. */
1693 TYPE_MODE (type
) = mode_for_size (FUNCTION_BOUNDARY
, MODE_INT
, 0);
1694 TYPE_SIZE (type
) = bitsize_int (FUNCTION_BOUNDARY
);
1695 TYPE_SIZE_UNIT (type
) = size_int (FUNCTION_BOUNDARY
/ BITS_PER_UNIT
);
1699 case REFERENCE_TYPE
:
1702 enum machine_mode mode
= ((TREE_CODE (type
) == REFERENCE_TYPE
1703 && reference_types_internal
)
1704 ? Pmode
: TYPE_MODE (type
));
1706 int nbits
= GET_MODE_BITSIZE (mode
);
1708 TYPE_SIZE (type
) = bitsize_int (nbits
);
1709 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (mode
));
1710 TYPE_UNSIGNED (type
) = 1;
1711 TYPE_PRECISION (type
) = nbits
;
1717 tree index
= TYPE_DOMAIN (type
);
1718 tree element
= TREE_TYPE (type
);
1720 build_pointer_type (element
);
1722 /* We need to know both bounds in order to compute the size. */
1723 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1724 && TYPE_SIZE (element
))
1726 tree ub
= TYPE_MAX_VALUE (index
);
1727 tree lb
= TYPE_MIN_VALUE (index
);
1731 /* The initial subtraction should happen in the original type so
1732 that (possible) negative values are handled appropriately. */
1733 length
= size_binop (PLUS_EXPR
, size_one_node
,
1734 fold_convert (sizetype
,
1735 fold_build2 (MINUS_EXPR
,
1739 /* Special handling for arrays of bits (for Chill). */
1740 element_size
= TYPE_SIZE (element
);
1741 if (TYPE_PACKED (type
) && INTEGRAL_TYPE_P (element
)
1742 && (integer_zerop (TYPE_MAX_VALUE (element
))
1743 || integer_onep (TYPE_MAX_VALUE (element
)))
1744 && host_integerp (TYPE_MIN_VALUE (element
), 1))
1746 HOST_WIDE_INT maxvalue
1747 = tree_low_cst (TYPE_MAX_VALUE (element
), 1);
1748 HOST_WIDE_INT minvalue
1749 = tree_low_cst (TYPE_MIN_VALUE (element
), 1);
1751 if (maxvalue
- minvalue
== 1
1752 && (maxvalue
== 1 || maxvalue
== 0))
1753 element_size
= integer_one_node
;
1756 /* If neither bound is a constant and sizetype is signed, make
1757 sure the size is never negative. We should really do this
1758 if *either* bound is non-constant, but this is the best
1759 compromise between C and Ada. */
1760 if (!TYPE_UNSIGNED (sizetype
)
1761 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
1762 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
1763 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
1765 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1766 fold_convert (bitsizetype
,
1769 /* If we know the size of the element, calculate the total
1770 size directly, rather than do some division thing below.
1771 This optimization helps Fortran assumed-size arrays
1772 (where the size of the array is determined at runtime)
1774 Note that we can't do this in the case where the size of
1775 the elements is one bit since TYPE_SIZE_UNIT cannot be
1776 set correctly in that case. */
1777 if (TYPE_SIZE_UNIT (element
) != 0 && ! integer_onep (element_size
))
1778 TYPE_SIZE_UNIT (type
)
1779 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1782 /* Now round the alignment and size,
1783 using machine-dependent criteria if any. */
1785 #ifdef ROUND_TYPE_ALIGN
1787 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1789 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1791 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (element
);
1792 TYPE_MODE (type
) = BLKmode
;
1793 if (TYPE_SIZE (type
) != 0
1794 #ifdef MEMBER_TYPE_FORCES_BLK
1795 && ! MEMBER_TYPE_FORCES_BLK (type
, VOIDmode
)
1797 /* BLKmode elements force BLKmode aggregate;
1798 else extract/store fields may lose. */
1799 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
1800 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
1802 /* One-element arrays get the component type's mode. */
1803 if (simple_cst_equal (TYPE_SIZE (type
),
1804 TYPE_SIZE (TREE_TYPE (type
))))
1805 TYPE_MODE (type
) = TYPE_MODE (TREE_TYPE (type
));
1808 = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1810 if (TYPE_MODE (type
) != BLKmode
1811 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
1812 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
))
1813 && TYPE_MODE (type
) != BLKmode
)
1815 TYPE_NO_FORCE_BLK (type
) = 1;
1816 TYPE_MODE (type
) = BLKmode
;
1824 case QUAL_UNION_TYPE
:
1827 record_layout_info rli
;
1829 /* Initialize the layout information. */
1830 rli
= start_record_layout (type
);
1832 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1833 in the reverse order in building the COND_EXPR that denotes
1834 its size. We reverse them again later. */
1835 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1836 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1838 /* Place all the fields. */
1839 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1840 place_field (rli
, field
);
1842 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1843 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1845 if (lang_adjust_rli
)
1846 (*lang_adjust_rli
) (rli
);
1848 /* Finish laying out the record. */
1849 finish_record_layout (rli
, /*free_p=*/true);
1857 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1858 records and unions, finish_record_layout already called this
1860 if (TREE_CODE (type
) != RECORD_TYPE
1861 && TREE_CODE (type
) != UNION_TYPE
1862 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
1863 finalize_type_size (type
);
1865 /* If an alias set has been set for this aggregate when it was incomplete,
1866 force it into alias set 0.
1867 This is too conservative, but we cannot call record_component_aliases
1868 here because some frontends still change the aggregates after
1870 if (AGGREGATE_TYPE_P (type
) && TYPE_ALIAS_SET_KNOWN_P (type
))
1871 TYPE_ALIAS_SET (type
) = 0;
1874 /* Create and return a type for signed integers of PRECISION bits. */
1877 make_signed_type (int precision
)
1879 tree type
= make_node (INTEGER_TYPE
);
1881 TYPE_PRECISION (type
) = precision
;
1883 fixup_signed_type (type
);
1887 /* Create and return a type for unsigned integers of PRECISION bits. */
1890 make_unsigned_type (int precision
)
1892 tree type
= make_node (INTEGER_TYPE
);
1894 TYPE_PRECISION (type
) = precision
;
1896 fixup_unsigned_type (type
);
1900 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1901 value to enable integer types to be created. */
1904 initialize_sizetypes (bool signed_p
)
1906 tree t
= make_node (INTEGER_TYPE
);
1908 TYPE_MODE (t
) = SImode
;
1909 TYPE_ALIGN (t
) = GET_MODE_ALIGNMENT (SImode
);
1910 TYPE_USER_ALIGN (t
) = 0;
1911 TYPE_IS_SIZETYPE (t
) = 1;
1912 TYPE_UNSIGNED (t
) = !signed_p
;
1913 TYPE_SIZE (t
) = build_int_cst (t
, GET_MODE_BITSIZE (SImode
));
1914 TYPE_SIZE_UNIT (t
) = build_int_cst (t
, GET_MODE_SIZE (SImode
));
1915 TYPE_PRECISION (t
) = GET_MODE_BITSIZE (SImode
);
1916 TYPE_MIN_VALUE (t
) = build_int_cst (t
, 0);
1918 /* 1000 avoids problems with possible overflow and is certainly
1919 larger than any size value we'd want to be storing. */
1920 TYPE_MAX_VALUE (t
) = build_int_cst (t
, 1000);
1923 bitsizetype
= build_distinct_type_copy (t
);
1926 /* Make sizetype a version of TYPE, and initialize *sizetype
1927 accordingly. We do this by overwriting the stub sizetype and
1928 bitsizetype nodes created by initialize_sizetypes. This makes sure
1929 that (a) anything stubby about them no longer exists, (b) any
1930 INTEGER_CSTs created with such a type, remain valid. */
1933 set_sizetype (tree type
)
1935 int oprecision
= TYPE_PRECISION (type
);
1936 /* The *bitsizetype types use a precision that avoids overflows when
1937 calculating signed sizes / offsets in bits. However, when
1938 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1940 int precision
= MIN (oprecision
+ BITS_PER_UNIT_LOG
+ 1,
1941 2 * HOST_BITS_PER_WIDE_INT
);
1944 gcc_assert (TYPE_UNSIGNED (type
) == TYPE_UNSIGNED (sizetype
));
1946 t
= build_distinct_type_copy (type
);
1947 /* We do want to use sizetype's cache, as we will be replacing that
1949 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (sizetype
);
1950 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (sizetype
);
1951 TREE_TYPE (TYPE_CACHED_VALUES (t
)) = type
;
1952 TYPE_UID (t
) = TYPE_UID (sizetype
);
1953 TYPE_IS_SIZETYPE (t
) = 1;
1955 /* Replace our original stub sizetype. */
1956 memcpy (sizetype
, t
, tree_size (sizetype
));
1957 TYPE_MAIN_VARIANT (sizetype
) = sizetype
;
1959 t
= make_node (INTEGER_TYPE
);
1960 TYPE_NAME (t
) = get_identifier ("bit_size_type");
1961 /* We do want to use bitsizetype's cache, as we will be replacing that
1963 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (bitsizetype
);
1964 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (bitsizetype
);
1965 TYPE_PRECISION (t
) = precision
;
1966 TYPE_UID (t
) = TYPE_UID (bitsizetype
);
1967 TYPE_IS_SIZETYPE (t
) = 1;
1968 /* Replace our original stub bitsizetype. */
1969 memcpy (bitsizetype
, t
, tree_size (bitsizetype
));
1971 if (TYPE_UNSIGNED (type
))
1973 fixup_unsigned_type (bitsizetype
);
1974 ssizetype
= build_distinct_type_copy (make_signed_type (oprecision
));
1975 TYPE_IS_SIZETYPE (ssizetype
) = 1;
1976 sbitsizetype
= build_distinct_type_copy (make_signed_type (precision
));
1977 TYPE_IS_SIZETYPE (sbitsizetype
) = 1;
1981 fixup_signed_type (bitsizetype
);
1982 ssizetype
= sizetype
;
1983 sbitsizetype
= bitsizetype
;
1987 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1988 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1989 for TYPE, based on the PRECISION and whether or not the TYPE
1990 IS_UNSIGNED. PRECISION need not correspond to a width supported
1991 natively by the hardware; for example, on a machine with 8-bit,
1992 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1996 set_min_and_max_values_for_integral_type (tree type
,
2005 min_value
= build_int_cst (type
, 0);
2007 = build_int_cst_wide (type
, precision
- HOST_BITS_PER_WIDE_INT
>= 0
2009 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
2010 precision
- HOST_BITS_PER_WIDE_INT
> 0
2011 ? ((unsigned HOST_WIDE_INT
) ~0
2012 >> (HOST_BITS_PER_WIDE_INT
2013 - (precision
- HOST_BITS_PER_WIDE_INT
)))
2019 = build_int_cst_wide (type
,
2020 (precision
- HOST_BITS_PER_WIDE_INT
> 0
2022 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
2023 (((HOST_WIDE_INT
) (-1)
2024 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
2025 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
2028 = build_int_cst_wide (type
,
2029 (precision
- HOST_BITS_PER_WIDE_INT
> 0
2031 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
2032 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
2033 ? (((HOST_WIDE_INT
) 1
2034 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
2038 TYPE_MIN_VALUE (type
) = min_value
;
2039 TYPE_MAX_VALUE (type
) = max_value
;
2042 /* Set the extreme values of TYPE based on its precision in bits,
2043 then lay it out. Used when make_signed_type won't do
2044 because the tree code is not INTEGER_TYPE.
2045 E.g. for Pascal, when the -fsigned-char option is given. */
2048 fixup_signed_type (tree type
)
2050 int precision
= TYPE_PRECISION (type
);
2052 /* We can not represent properly constants greater then
2053 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2054 as they are used by i386 vector extensions and friends. */
2055 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2056 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2058 set_min_and_max_values_for_integral_type (type
, precision
,
2059 /*is_unsigned=*/false);
2061 /* Lay out the type: set its alignment, size, etc. */
2065 /* Set the extreme values of TYPE based on its precision in bits,
2066 then lay it out. This is used both in `make_unsigned_type'
2067 and for enumeral types. */
2070 fixup_unsigned_type (tree type
)
2072 int precision
= TYPE_PRECISION (type
);
2074 /* We can not represent properly constants greater then
2075 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2076 as they are used by i386 vector extensions and friends. */
2077 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2078 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2080 TYPE_UNSIGNED (type
) = 1;
2082 set_min_and_max_values_for_integral_type (type
, precision
,
2083 /*is_unsigned=*/true);
2085 /* Lay out the type: set its alignment, size, etc. */
2089 /* Find the best machine mode to use when referencing a bit field of length
2090 BITSIZE bits starting at BITPOS.
2092 The underlying object is known to be aligned to a boundary of ALIGN bits.
2093 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2094 larger than LARGEST_MODE (usually SImode).
2096 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2097 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2098 mode meeting these conditions.
2100 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2101 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2102 all the conditions. */
2105 get_best_mode (int bitsize
, int bitpos
, unsigned int align
,
2106 enum machine_mode largest_mode
, int volatilep
)
2108 enum machine_mode mode
;
2109 unsigned int unit
= 0;
2111 /* Find the narrowest integer mode that contains the bit field. */
2112 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
2113 mode
= GET_MODE_WIDER_MODE (mode
))
2115 unit
= GET_MODE_BITSIZE (mode
);
2116 if ((bitpos
% unit
) + bitsize
<= unit
)
2120 if (mode
== VOIDmode
2121 /* It is tempting to omit the following line
2122 if STRICT_ALIGNMENT is true.
2123 But that is incorrect, since if the bitfield uses part of 3 bytes
2124 and we use a 4-byte mode, we could get a spurious segv
2125 if the extra 4th byte is past the end of memory.
2126 (Though at least one Unix compiler ignores this problem:
2127 that on the Sequent 386 machine. */
2128 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
2129 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
2132 if (SLOW_BYTE_ACCESS
&& ! volatilep
)
2134 enum machine_mode wide_mode
= VOIDmode
, tmode
;
2136 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
2137 tmode
= GET_MODE_WIDER_MODE (tmode
))
2139 unit
= GET_MODE_BITSIZE (tmode
);
2140 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
2141 && unit
<= BITS_PER_WORD
2142 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
2143 && (largest_mode
== VOIDmode
2144 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
2148 if (wide_mode
!= VOIDmode
)
2155 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2156 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2159 get_mode_bounds (enum machine_mode mode
, int sign
,
2160 enum machine_mode target_mode
,
2161 rtx
*mmin
, rtx
*mmax
)
2163 unsigned size
= GET_MODE_BITSIZE (mode
);
2164 unsigned HOST_WIDE_INT min_val
, max_val
;
2166 gcc_assert (size
<= HOST_BITS_PER_WIDE_INT
);
2170 min_val
= -((unsigned HOST_WIDE_INT
) 1 << (size
- 1));
2171 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1)) - 1;
2176 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1) << 1) - 1;
2179 *mmin
= gen_int_mode (min_val
, target_mode
);
2180 *mmax
= gen_int_mode (max_val
, target_mode
);
2183 #include "gt-stor-layout.h"