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, 2006
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 2, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING. If not, write to the Free
20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
26 #include "coretypes.h"
38 #include "langhooks.h"
42 /* Data type for the expressions representing sizes of data types.
43 It is the first integer type laid out. */
44 tree sizetype_tab
[(int) TYPE_KIND_LAST
];
46 /* If nonzero, this is an upper limit on alignment of structure fields.
47 The value is measured in bits. */
48 unsigned int maximum_field_alignment
= TARGET_DEFAULT_PACK_STRUCT
* BITS_PER_UNIT
;
49 /* ... and its original value in bytes, specified via -fpack-struct=<value>. */
50 unsigned int initial_max_fld_align
= TARGET_DEFAULT_PACK_STRUCT
;
52 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
53 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
54 called only by a front end. */
55 static int reference_types_internal
= 0;
57 static void finalize_record_size (record_layout_info
);
58 static void finalize_type_size (tree
);
59 static void place_union_field (record_layout_info
, tree
);
60 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
61 static int excess_unit_span (HOST_WIDE_INT
, HOST_WIDE_INT
, HOST_WIDE_INT
,
64 extern void debug_rli (record_layout_info
);
66 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
68 static GTY(()) tree pending_sizes
;
70 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
74 internal_reference_types (void)
76 reference_types_internal
= 1;
79 /* Get a list of all the objects put on the pending sizes list. */
82 get_pending_sizes (void)
84 tree chain
= pending_sizes
;
90 /* Add EXPR to the pending sizes list. */
93 put_pending_size (tree expr
)
95 /* Strip any simple arithmetic from EXPR to see if it has an underlying
97 expr
= skip_simple_arithmetic (expr
);
99 if (TREE_CODE (expr
) == SAVE_EXPR
)
100 pending_sizes
= tree_cons (NULL_TREE
, expr
, pending_sizes
);
103 /* Put a chain of objects into the pending sizes list, which must be
107 put_pending_sizes (tree chain
)
109 gcc_assert (!pending_sizes
);
110 pending_sizes
= chain
;
113 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
114 to serve as the actual size-expression for a type or decl. */
117 variable_size (tree size
)
121 /* If the language-processor is to take responsibility for variable-sized
122 items (e.g., languages which have elaboration procedures like Ada),
123 just return SIZE unchanged. Likewise for self-referential sizes and
125 if (TREE_CONSTANT (size
)
126 || lang_hooks
.decls
.global_bindings_p () < 0
127 || CONTAINS_PLACEHOLDER_P (size
))
130 size
= save_expr (size
);
132 /* If an array with a variable number of elements is declared, and
133 the elements require destruction, we will emit a cleanup for the
134 array. That cleanup is run both on normal exit from the block
135 and in the exception-handler for the block. Normally, when code
136 is used in both ordinary code and in an exception handler it is
137 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
138 not wish to do that here; the array-size is the same in both
140 save
= skip_simple_arithmetic (size
);
142 if (cfun
&& cfun
->x_dont_save_pending_sizes_p
)
143 /* The front-end doesn't want us to keep a list of the expressions
144 that determine sizes for variable size objects. Trust it. */
147 if (lang_hooks
.decls
.global_bindings_p ())
149 if (TREE_CONSTANT (size
))
150 error ("type size can%'t be explicitly evaluated");
152 error ("variable-size type declared outside of any function");
154 return size_one_node
;
157 put_pending_size (save
);
162 #ifndef MAX_FIXED_MODE_SIZE
163 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
166 /* Return the machine mode to use for a nonscalar of SIZE bits. The
167 mode must be in class CLASS, and have exactly that many value bits;
168 it may have padding as well. If LIMIT is nonzero, modes of wider
169 than MAX_FIXED_MODE_SIZE will not be used. */
172 mode_for_size (unsigned int size
, enum mode_class
class, int limit
)
174 enum machine_mode mode
;
176 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
179 /* Get the first mode which has this size, in the specified class. */
180 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
181 mode
= GET_MODE_WIDER_MODE (mode
))
182 if (GET_MODE_PRECISION (mode
) == size
)
188 /* Similar, except passed a tree node. */
191 mode_for_size_tree (tree size
, enum mode_class
class, int limit
)
193 unsigned HOST_WIDE_INT uhwi
;
196 if (!host_integerp (size
, 1))
198 uhwi
= tree_low_cst (size
, 1);
202 return mode_for_size (ui
, class, limit
);
205 /* Similar, but never return BLKmode; return the narrowest mode that
206 contains at least the requested number of value bits. */
209 smallest_mode_for_size (unsigned int size
, enum mode_class
class)
211 enum machine_mode mode
;
213 /* Get the first mode which has at least this size, in the
215 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
216 mode
= GET_MODE_WIDER_MODE (mode
))
217 if (GET_MODE_PRECISION (mode
) >= size
)
223 /* Find an integer mode of the exact same size, or BLKmode on failure. */
226 int_mode_for_mode (enum machine_mode mode
)
228 switch (GET_MODE_CLASS (mode
))
231 case MODE_PARTIAL_INT
:
234 case MODE_COMPLEX_INT
:
235 case MODE_COMPLEX_FLOAT
:
237 case MODE_DECIMAL_FLOAT
:
238 case MODE_VECTOR_INT
:
239 case MODE_VECTOR_FLOAT
:
240 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
247 /* ... fall through ... */
257 /* Return the alignment of MODE. This will be bounded by 1 and
258 BIGGEST_ALIGNMENT. */
261 get_mode_alignment (enum machine_mode mode
)
263 return MIN (BIGGEST_ALIGNMENT
, MAX (1, mode_base_align
[mode
]*BITS_PER_UNIT
));
267 /* Subroutine of layout_decl: Force alignment required for the data type.
268 But if the decl itself wants greater alignment, don't override that. */
271 do_type_align (tree type
, tree decl
)
273 if (TYPE_ALIGN (type
) > DECL_ALIGN (decl
))
275 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
276 if (TREE_CODE (decl
) == FIELD_DECL
)
277 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
281 /* Set the size, mode and alignment of a ..._DECL node.
282 TYPE_DECL does need this for C++.
283 Note that LABEL_DECL and CONST_DECL nodes do not need this,
284 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
285 Don't call layout_decl for them.
287 KNOWN_ALIGN is the amount of alignment we can assume this
288 decl has with no special effort. It is relevant only for FIELD_DECLs
289 and depends on the previous fields.
290 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
291 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
292 the record will be aligned to suit. */
295 layout_decl (tree decl
, unsigned int known_align
)
297 tree type
= TREE_TYPE (decl
);
298 enum tree_code code
= TREE_CODE (decl
);
301 if (code
== CONST_DECL
)
304 gcc_assert (code
== VAR_DECL
|| code
== PARM_DECL
|| code
== RESULT_DECL
305 || code
== TYPE_DECL
||code
== FIELD_DECL
);
307 rtl
= DECL_RTL_IF_SET (decl
);
309 if (type
== error_mark_node
)
310 type
= void_type_node
;
312 /* Usually the size and mode come from the data type without change,
313 however, the front-end may set the explicit width of the field, so its
314 size may not be the same as the size of its type. This happens with
315 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
316 also happens with other fields. For example, the C++ front-end creates
317 zero-sized fields corresponding to empty base classes, and depends on
318 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
319 size in bytes from the size in bits. If we have already set the mode,
320 don't set it again since we can be called twice for FIELD_DECLs. */
322 DECL_UNSIGNED (decl
) = TYPE_UNSIGNED (type
);
323 if (DECL_MODE (decl
) == VOIDmode
)
324 DECL_MODE (decl
) = TYPE_MODE (type
);
326 if (DECL_SIZE (decl
) == 0)
328 DECL_SIZE (decl
) = TYPE_SIZE (type
);
329 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
331 else if (DECL_SIZE_UNIT (decl
) == 0)
332 DECL_SIZE_UNIT (decl
)
333 = fold_convert (sizetype
, size_binop (CEIL_DIV_EXPR
, DECL_SIZE (decl
),
336 if (code
!= FIELD_DECL
)
337 /* For non-fields, update the alignment from the type. */
338 do_type_align (type
, decl
);
340 /* For fields, it's a bit more complicated... */
342 bool old_user_align
= DECL_USER_ALIGN (decl
);
343 bool zero_bitfield
= false;
344 bool packed_p
= DECL_PACKED (decl
);
347 if (DECL_BIT_FIELD (decl
))
349 DECL_BIT_FIELD_TYPE (decl
) = type
;
351 /* A zero-length bit-field affects the alignment of the next
352 field. In essence such bit-fields are not influenced by
353 any packing due to #pragma pack or attribute packed. */
354 if (integer_zerop (DECL_SIZE (decl
))
355 && ! targetm
.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl
)))
357 zero_bitfield
= true;
359 #ifdef PCC_BITFIELD_TYPE_MATTERS
360 if (PCC_BITFIELD_TYPE_MATTERS
)
361 do_type_align (type
, decl
);
365 #ifdef EMPTY_FIELD_BOUNDARY
366 if (EMPTY_FIELD_BOUNDARY
> DECL_ALIGN (decl
))
368 DECL_ALIGN (decl
) = EMPTY_FIELD_BOUNDARY
;
369 DECL_USER_ALIGN (decl
) = 0;
375 /* See if we can use an ordinary integer mode for a bit-field.
376 Conditions are: a fixed size that is correct for another mode
377 and occupying a complete byte or bytes on proper boundary. */
378 if (TYPE_SIZE (type
) != 0
379 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
380 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
)
382 enum machine_mode xmode
383 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
387 || known_align
>= GET_MODE_ALIGNMENT (xmode
)))
389 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
391 DECL_MODE (decl
) = xmode
;
392 DECL_BIT_FIELD (decl
) = 0;
396 /* Turn off DECL_BIT_FIELD if we won't need it set. */
397 if (TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
398 && known_align
>= TYPE_ALIGN (type
)
399 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
))
400 DECL_BIT_FIELD (decl
) = 0;
402 else if (packed_p
&& DECL_USER_ALIGN (decl
))
403 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
404 round up; we'll reduce it again below. We want packing to
405 supersede USER_ALIGN inherited from the type, but defer to
406 alignment explicitly specified on the field decl. */;
408 do_type_align (type
, decl
);
410 /* If the field is of variable size, we can't misalign it since we
411 have no way to make a temporary to align the result. But this
412 isn't an issue if the decl is not addressable. Likewise if it
415 Note that do_type_align may set DECL_USER_ALIGN, so we need to
416 check old_user_align instead. */
419 && (DECL_NONADDRESSABLE_P (decl
)
420 || DECL_SIZE_UNIT (decl
) == 0
421 || TREE_CODE (DECL_SIZE_UNIT (decl
)) == INTEGER_CST
))
422 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
424 if (! packed_p
&& ! DECL_USER_ALIGN (decl
))
426 /* Some targets (i.e. i386, VMS) limit struct field alignment
427 to a lower boundary than alignment of variables unless
428 it was overridden by attribute aligned. */
429 #ifdef BIGGEST_FIELD_ALIGNMENT
431 = MIN (DECL_ALIGN (decl
), (unsigned) BIGGEST_FIELD_ALIGNMENT
);
433 #ifdef ADJUST_FIELD_ALIGN
434 DECL_ALIGN (decl
) = ADJUST_FIELD_ALIGN (decl
, DECL_ALIGN (decl
));
439 mfa
= initial_max_fld_align
* BITS_PER_UNIT
;
441 mfa
= maximum_field_alignment
;
442 /* Should this be controlled by DECL_USER_ALIGN, too? */
444 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), mfa
);
447 /* Evaluate nonconstant size only once, either now or as soon as safe. */
448 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
449 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
450 if (DECL_SIZE_UNIT (decl
) != 0
451 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
452 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
454 /* If requested, warn about definitions of large data objects. */
456 && (code
== VAR_DECL
|| code
== PARM_DECL
)
457 && ! DECL_EXTERNAL (decl
))
459 tree size
= DECL_SIZE_UNIT (decl
);
461 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
462 && compare_tree_int (size
, larger_than_size
) > 0)
464 int size_as_int
= TREE_INT_CST_LOW (size
);
466 if (compare_tree_int (size
, size_as_int
) == 0)
467 warning (0, "size of %q+D is %d bytes", decl
, size_as_int
);
469 warning (0, "size of %q+D is larger than %wd bytes",
470 decl
, larger_than_size
);
474 /* If the RTL was already set, update its mode and mem attributes. */
477 PUT_MODE (rtl
, DECL_MODE (decl
));
478 SET_DECL_RTL (decl
, 0);
479 set_mem_attributes (rtl
, decl
, 1);
480 SET_DECL_RTL (decl
, rtl
);
484 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
485 a previous call to layout_decl and calls it again. */
488 relayout_decl (tree decl
)
490 DECL_SIZE (decl
) = DECL_SIZE_UNIT (decl
) = 0;
491 DECL_MODE (decl
) = VOIDmode
;
492 DECL_ALIGN (decl
) = 0;
493 SET_DECL_RTL (decl
, 0);
495 layout_decl (decl
, 0);
498 /* Hook for a front-end function that can modify the record layout as needed
499 immediately before it is finalized. */
501 static void (*lang_adjust_rli
) (record_layout_info
) = 0;
504 set_lang_adjust_rli (void (*f
) (record_layout_info
))
509 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
510 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
511 is to be passed to all other layout functions for this record. It is the
512 responsibility of the caller to call `free' for the storage returned.
513 Note that garbage collection is not permitted until we finish laying
517 start_record_layout (tree t
)
519 record_layout_info rli
= xmalloc (sizeof (struct record_layout_info_s
));
523 /* If the type has a minimum specified alignment (via an attribute
524 declaration, for example) use it -- otherwise, start with a
525 one-byte alignment. */
526 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
527 rli
->unpacked_align
= rli
->record_align
;
528 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
530 #ifdef STRUCTURE_SIZE_BOUNDARY
531 /* Packed structures don't need to have minimum size. */
532 if (! TYPE_PACKED (t
))
533 rli
->record_align
= MAX (rli
->record_align
, (unsigned) STRUCTURE_SIZE_BOUNDARY
);
536 rli
->offset
= size_zero_node
;
537 rli
->bitpos
= bitsize_zero_node
;
539 rli
->pending_statics
= 0;
540 rli
->packed_maybe_necessary
= 0;
541 rli
->remaining_in_alignment
= 0;
546 /* These four routines perform computations that convert between
547 the offset/bitpos forms and byte and bit offsets. */
550 bit_from_pos (tree offset
, tree bitpos
)
552 return size_binop (PLUS_EXPR
, bitpos
,
553 size_binop (MULT_EXPR
,
554 fold_convert (bitsizetype
, offset
),
559 byte_from_pos (tree offset
, tree bitpos
)
561 return size_binop (PLUS_EXPR
, offset
,
562 fold_convert (sizetype
,
563 size_binop (TRUNC_DIV_EXPR
, bitpos
,
564 bitsize_unit_node
)));
568 pos_from_bit (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
,
571 *poffset
= size_binop (MULT_EXPR
,
572 fold_convert (sizetype
,
573 size_binop (FLOOR_DIV_EXPR
, pos
,
574 bitsize_int (off_align
))),
575 size_int (off_align
/ BITS_PER_UNIT
));
576 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
579 /* Given a pointer to bit and byte offsets and an offset alignment,
580 normalize the offsets so they are within the alignment. */
583 normalize_offset (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
)
585 /* If the bit position is now larger than it should be, adjust it
587 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
589 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
590 bitsize_int (off_align
));
593 = size_binop (PLUS_EXPR
, *poffset
,
594 size_binop (MULT_EXPR
,
595 fold_convert (sizetype
, extra_aligns
),
596 size_int (off_align
/ BITS_PER_UNIT
)));
599 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
603 /* Print debugging information about the information in RLI. */
606 debug_rli (record_layout_info rli
)
608 print_node_brief (stderr
, "type", rli
->t
, 0);
609 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
610 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
612 fprintf (stderr
, "\naligns: rec = %u, unpack = %u, off = %u\n",
613 rli
->record_align
, rli
->unpacked_align
,
616 /* The ms_struct code is the only that uses this. */
617 if (targetm
.ms_bitfield_layout_p (rli
->t
))
618 fprintf (stderr
, "remaining in alignment = %u\n", rli
->remaining_in_alignment
);
620 if (rli
->packed_maybe_necessary
)
621 fprintf (stderr
, "packed may be necessary\n");
623 if (rli
->pending_statics
)
625 fprintf (stderr
, "pending statics:\n");
626 debug_tree (rli
->pending_statics
);
630 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
631 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
634 normalize_rli (record_layout_info rli
)
636 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
639 /* Returns the size in bytes allocated so far. */
642 rli_size_unit_so_far (record_layout_info rli
)
644 return byte_from_pos (rli
->offset
, rli
->bitpos
);
647 /* Returns the size in bits allocated so far. */
650 rli_size_so_far (record_layout_info rli
)
652 return bit_from_pos (rli
->offset
, rli
->bitpos
);
655 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
656 the next available location within the record is given by KNOWN_ALIGN.
657 Update the variable alignment fields in RLI, and return the alignment
658 to give the FIELD. */
661 update_alignment_for_field (record_layout_info rli
, tree field
,
662 unsigned int known_align
)
664 /* The alignment required for FIELD. */
665 unsigned int desired_align
;
666 /* The type of this field. */
667 tree type
= TREE_TYPE (field
);
668 /* True if the field was explicitly aligned by the user. */
672 /* Do not attempt to align an ERROR_MARK node */
673 if (TREE_CODE (type
) == ERROR_MARK
)
676 /* Lay out the field so we know what alignment it needs. */
677 layout_decl (field
, known_align
);
678 desired_align
= DECL_ALIGN (field
);
679 user_align
= DECL_USER_ALIGN (field
);
681 is_bitfield
= (type
!= error_mark_node
682 && DECL_BIT_FIELD_TYPE (field
)
683 && ! integer_zerop (TYPE_SIZE (type
)));
685 /* Record must have at least as much alignment as any field.
686 Otherwise, the alignment of the field within the record is
688 if (targetm
.ms_bitfield_layout_p (rli
->t
))
690 /* Here, the alignment of the underlying type of a bitfield can
691 affect the alignment of a record; even a zero-sized field
692 can do this. The alignment should be to the alignment of
693 the type, except that for zero-size bitfields this only
694 applies if there was an immediately prior, nonzero-size
695 bitfield. (That's the way it is, experimentally.) */
697 || (!integer_zerop (DECL_SIZE (field
))
698 ? !DECL_PACKED (field
)
700 && DECL_BIT_FIELD_TYPE (rli
->prev_field
)
701 && ! integer_zerop (DECL_SIZE (rli
->prev_field
)))))
703 unsigned int type_align
= TYPE_ALIGN (type
);
704 type_align
= MAX (type_align
, desired_align
);
705 if (maximum_field_alignment
!= 0)
706 type_align
= MIN (type_align
, maximum_field_alignment
);
707 rli
->record_align
= MAX (rli
->record_align
, type_align
);
708 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
711 #ifdef PCC_BITFIELD_TYPE_MATTERS
712 else if (is_bitfield
&& PCC_BITFIELD_TYPE_MATTERS
)
714 /* Named bit-fields cause the entire structure to have the
715 alignment implied by their type. Some targets also apply the same
716 rules to unnamed bitfields. */
717 if (DECL_NAME (field
) != 0
718 || targetm
.align_anon_bitfield ())
720 unsigned int type_align
= TYPE_ALIGN (type
);
722 #ifdef ADJUST_FIELD_ALIGN
723 if (! TYPE_USER_ALIGN (type
))
724 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
727 /* Targets might chose to handle unnamed and hence possibly
728 zero-width bitfield. Those are not influenced by #pragmas
729 or packed attributes. */
730 if (integer_zerop (DECL_SIZE (field
)))
732 if (initial_max_fld_align
)
733 type_align
= MIN (type_align
,
734 initial_max_fld_align
* BITS_PER_UNIT
);
736 else if (maximum_field_alignment
!= 0)
737 type_align
= MIN (type_align
, maximum_field_alignment
);
738 else if (DECL_PACKED (field
))
739 type_align
= MIN (type_align
, BITS_PER_UNIT
);
741 /* The alignment of the record is increased to the maximum
742 of the current alignment, the alignment indicated on the
743 field (i.e., the alignment specified by an __aligned__
744 attribute), and the alignment indicated by the type of
746 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
747 rli
->record_align
= MAX (rli
->record_align
, type_align
);
750 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
751 user_align
|= TYPE_USER_ALIGN (type
);
757 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
758 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
761 TYPE_USER_ALIGN (rli
->t
) |= user_align
;
763 return desired_align
;
766 /* Called from place_field to handle unions. */
769 place_union_field (record_layout_info rli
, tree field
)
771 update_alignment_for_field (rli
, field
, /*known_align=*/0);
773 DECL_FIELD_OFFSET (field
) = size_zero_node
;
774 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
775 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
777 /* If this is an ERROR_MARK return *after* having set the
778 field at the start of the union. This helps when parsing
780 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
)
783 /* We assume the union's size will be a multiple of a byte so we don't
784 bother with BITPOS. */
785 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
786 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
787 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
788 rli
->offset
= fold_build3 (COND_EXPR
, sizetype
,
789 DECL_QUALIFIER (field
),
790 DECL_SIZE_UNIT (field
), rli
->offset
);
793 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
794 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
795 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
796 units of alignment than the underlying TYPE. */
798 excess_unit_span (HOST_WIDE_INT byte_offset
, HOST_WIDE_INT bit_offset
,
799 HOST_WIDE_INT size
, HOST_WIDE_INT align
, tree type
)
801 /* Note that the calculation of OFFSET might overflow; we calculate it so
802 that we still get the right result as long as ALIGN is a power of two. */
803 unsigned HOST_WIDE_INT offset
= byte_offset
* BITS_PER_UNIT
+ bit_offset
;
805 offset
= offset
% align
;
806 return ((offset
+ size
+ align
- 1) / align
807 > ((unsigned HOST_WIDE_INT
) tree_low_cst (TYPE_SIZE (type
), 1)
812 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
813 is a FIELD_DECL to be added after those fields already present in
814 T. (FIELD is not actually added to the TYPE_FIELDS list here;
815 callers that desire that behavior must manually perform that step.) */
818 place_field (record_layout_info rli
, tree field
)
820 /* The alignment required for FIELD. */
821 unsigned int desired_align
;
822 /* The alignment FIELD would have if we just dropped it into the
823 record as it presently stands. */
824 unsigned int known_align
;
825 unsigned int actual_align
;
826 /* The type of this field. */
827 tree type
= TREE_TYPE (field
);
829 gcc_assert (TREE_CODE (field
) != ERROR_MARK
);
831 /* If FIELD is static, then treat it like a separate variable, not
832 really like a structure field. If it is a FUNCTION_DECL, it's a
833 method. In both cases, all we do is lay out the decl, and we do
834 it *after* the record is laid out. */
835 if (TREE_CODE (field
) == VAR_DECL
)
837 rli
->pending_statics
= tree_cons (NULL_TREE
, field
,
838 rli
->pending_statics
);
842 /* Enumerators and enum types which are local to this class need not
843 be laid out. Likewise for initialized constant fields. */
844 else if (TREE_CODE (field
) != FIELD_DECL
)
847 /* Unions are laid out very differently than records, so split
848 that code off to another function. */
849 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
851 place_union_field (rli
, field
);
855 else if (TREE_CODE (type
) == ERROR_MARK
)
857 /* Place this field at the current allocation position, so we
858 maintain monotonicity. */
859 DECL_FIELD_OFFSET (field
) = rli
->offset
;
860 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
861 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
865 /* Work out the known alignment so far. Note that A & (-A) is the
866 value of the least-significant bit in A that is one. */
867 if (! integer_zerop (rli
->bitpos
))
868 known_align
= (tree_low_cst (rli
->bitpos
, 1)
869 & - tree_low_cst (rli
->bitpos
, 1));
870 else if (integer_zerop (rli
->offset
))
872 else if (host_integerp (rli
->offset
, 1))
873 known_align
= (BITS_PER_UNIT
874 * (tree_low_cst (rli
->offset
, 1)
875 & - tree_low_cst (rli
->offset
, 1)));
877 known_align
= rli
->offset_align
;
879 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
880 if (known_align
== 0)
881 known_align
= MAX (BIGGEST_ALIGNMENT
, rli
->record_align
);
883 if (warn_packed
&& DECL_PACKED (field
))
885 if (known_align
>= TYPE_ALIGN (type
))
887 if (TYPE_ALIGN (type
) > desired_align
)
889 if (STRICT_ALIGNMENT
)
890 warning (OPT_Wattributes
, "packed attribute causes "
891 "inefficient alignment for %q+D", field
);
893 warning (OPT_Wattributes
, "packed attribute is "
894 "unnecessary for %q+D", field
);
898 rli
->packed_maybe_necessary
= 1;
901 /* Does this field automatically have alignment it needs by virtue
902 of the fields that precede it and the record's own alignment?
903 We already align ms_struct fields, so don't re-align them. */
904 if (known_align
< desired_align
905 && !targetm
.ms_bitfield_layout_p (rli
->t
))
907 /* No, we need to skip space before this field.
908 Bump the cumulative size to multiple of field alignment. */
910 warning (OPT_Wpadded
, "padding struct to align %q+D", field
);
912 /* If the alignment is still within offset_align, just align
914 if (desired_align
< rli
->offset_align
)
915 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
918 /* First adjust OFFSET by the partial bits, then align. */
920 = size_binop (PLUS_EXPR
, rli
->offset
,
921 fold_convert (sizetype
,
922 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
923 bitsize_unit_node
)));
924 rli
->bitpos
= bitsize_zero_node
;
926 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
929 if (! TREE_CONSTANT (rli
->offset
))
930 rli
->offset_align
= desired_align
;
934 /* Handle compatibility with PCC. Note that if the record has any
935 variable-sized fields, we need not worry about compatibility. */
936 #ifdef PCC_BITFIELD_TYPE_MATTERS
937 if (PCC_BITFIELD_TYPE_MATTERS
938 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
939 && TREE_CODE (field
) == FIELD_DECL
940 && type
!= error_mark_node
941 && DECL_BIT_FIELD (field
)
942 && ! DECL_PACKED (field
)
943 && maximum_field_alignment
== 0
944 && ! integer_zerop (DECL_SIZE (field
))
945 && host_integerp (DECL_SIZE (field
), 1)
946 && host_integerp (rli
->offset
, 1)
947 && host_integerp (TYPE_SIZE (type
), 1))
949 unsigned int type_align
= TYPE_ALIGN (type
);
950 tree dsize
= DECL_SIZE (field
);
951 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
952 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
953 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
955 #ifdef ADJUST_FIELD_ALIGN
956 if (! TYPE_USER_ALIGN (type
))
957 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
960 /* A bit field may not span more units of alignment of its type
961 than its type itself. Advance to next boundary if necessary. */
962 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
963 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
965 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
969 #ifdef BITFIELD_NBYTES_LIMITED
970 if (BITFIELD_NBYTES_LIMITED
971 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
972 && TREE_CODE (field
) == FIELD_DECL
973 && type
!= error_mark_node
974 && DECL_BIT_FIELD_TYPE (field
)
975 && ! DECL_PACKED (field
)
976 && ! integer_zerop (DECL_SIZE (field
))
977 && host_integerp (DECL_SIZE (field
), 1)
978 && host_integerp (rli
->offset
, 1)
979 && host_integerp (TYPE_SIZE (type
), 1))
981 unsigned int type_align
= TYPE_ALIGN (type
);
982 tree dsize
= DECL_SIZE (field
);
983 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
984 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
985 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
987 #ifdef ADJUST_FIELD_ALIGN
988 if (! TYPE_USER_ALIGN (type
))
989 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
992 if (maximum_field_alignment
!= 0)
993 type_align
= MIN (type_align
, maximum_field_alignment
);
994 /* ??? This test is opposite the test in the containing if
995 statement, so this code is unreachable currently. */
996 else if (DECL_PACKED (field
))
997 type_align
= MIN (type_align
, BITS_PER_UNIT
);
999 /* A bit field may not span the unit of alignment of its type.
1000 Advance to next boundary if necessary. */
1001 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
1002 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1004 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
1008 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1010 When a bit field is inserted into a packed record, the whole
1011 size of the underlying type is used by one or more same-size
1012 adjacent bitfields. (That is, if its long:3, 32 bits is
1013 used in the record, and any additional adjacent long bitfields are
1014 packed into the same chunk of 32 bits. However, if the size
1015 changes, a new field of that size is allocated.) In an unpacked
1016 record, this is the same as using alignment, but not equivalent
1019 Note: for compatibility, we use the type size, not the type alignment
1020 to determine alignment, since that matches the documentation */
1022 if (targetm
.ms_bitfield_layout_p (rli
->t
))
1024 tree prev_saved
= rli
->prev_field
;
1026 /* This is a bitfield if it exists. */
1027 if (rli
->prev_field
)
1029 /* If both are bitfields, nonzero, and the same size, this is
1030 the middle of a run. Zero declared size fields are special
1031 and handled as "end of run". (Note: it's nonzero declared
1032 size, but equal type sizes!) (Since we know that both
1033 the current and previous fields are bitfields by the
1034 time we check it, DECL_SIZE must be present for both.) */
1035 if (DECL_BIT_FIELD_TYPE (field
)
1036 && !integer_zerop (DECL_SIZE (field
))
1037 && !integer_zerop (DECL_SIZE (rli
->prev_field
))
1038 && host_integerp (DECL_SIZE (rli
->prev_field
), 0)
1039 && host_integerp (TYPE_SIZE (type
), 0)
1040 && simple_cst_equal (TYPE_SIZE (type
),
1041 TYPE_SIZE (TREE_TYPE (rli
->prev_field
))))
1043 /* We're in the middle of a run of equal type size fields; make
1044 sure we realign if we run out of bits. (Not decl size,
1046 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 1);
1048 if (rli
->remaining_in_alignment
< bitsize
)
1050 /* out of bits; bump up to next 'word'. */
1051 rli
->offset
= DECL_FIELD_OFFSET (rli
->prev_field
);
1053 = size_binop (PLUS_EXPR
, TYPE_SIZE (type
),
1054 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1055 rli
->prev_field
= field
;
1056 rli
->remaining_in_alignment
1057 = tree_low_cst (TYPE_SIZE (type
), 1);
1060 rli
->remaining_in_alignment
-= bitsize
;
1064 /* End of a run: if leaving a run of bitfields of the same type
1065 size, we have to "use up" the rest of the bits of the type
1068 Compute the new position as the sum of the size for the prior
1069 type and where we first started working on that type.
1070 Note: since the beginning of the field was aligned then
1071 of course the end will be too. No round needed. */
1073 if (!integer_zerop (DECL_SIZE (rli
->prev_field
))
1074 && rli
->remaining_in_alignment
)
1077 = size_binop (PLUS_EXPR
, rli
->bitpos
,
1078 bitsize_int (rli
->remaining_in_alignment
));
1081 /* We "use up" size zero fields; the code below should behave
1082 as if the prior field was not a bitfield. */
1085 /* Cause a new bitfield to be captured, either this time (if
1086 currently a bitfield) or next time we see one. */
1087 if (!DECL_BIT_FIELD_TYPE(field
)
1088 || integer_zerop (DECL_SIZE (field
)))
1089 rli
->prev_field
= NULL
;
1092 normalize_rli (rli
);
1095 /* If we're starting a new run of same size type bitfields
1096 (or a run of non-bitfields), set up the "first of the run"
1099 That is, if the current field is not a bitfield, or if there
1100 was a prior bitfield the type sizes differ, or if there wasn't
1101 a prior bitfield the size of the current field is nonzero.
1103 Note: we must be sure to test ONLY the type size if there was
1104 a prior bitfield and ONLY for the current field being zero if
1107 if (!DECL_BIT_FIELD_TYPE (field
)
1108 || ( prev_saved
!= NULL
1109 ? !simple_cst_equal (TYPE_SIZE (type
),
1110 TYPE_SIZE (TREE_TYPE (prev_saved
)))
1111 : !integer_zerop (DECL_SIZE (field
)) ))
1113 /* Never smaller than a byte for compatibility. */
1114 unsigned int type_align
= BITS_PER_UNIT
;
1116 /* (When not a bitfield), we could be seeing a flex array (with
1117 no DECL_SIZE). Since we won't be using remaining_in_alignment
1118 until we see a bitfield (and come by here again) we just skip
1120 if (DECL_SIZE (field
) != NULL
1121 && host_integerp (TYPE_SIZE (TREE_TYPE (field
)), 0)
1122 && host_integerp (DECL_SIZE (field
), 0))
1123 rli
->remaining_in_alignment
1124 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field
)), 1)
1125 - tree_low_cst (DECL_SIZE (field
), 1);
1127 /* Now align (conventionally) for the new type. */
1128 type_align
= TYPE_ALIGN (TREE_TYPE (field
));
1130 if (maximum_field_alignment
!= 0)
1131 type_align
= MIN (type_align
, maximum_field_alignment
);
1133 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1135 /* If we really aligned, don't allow subsequent bitfields
1137 rli
->prev_field
= NULL
;
1141 /* Offset so far becomes the position of this field after normalizing. */
1142 normalize_rli (rli
);
1143 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1144 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1145 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1147 /* If this field ended up more aligned than we thought it would be (we
1148 approximate this by seeing if its position changed), lay out the field
1149 again; perhaps we can use an integral mode for it now. */
1150 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
1151 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
1152 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
1153 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
1154 actual_align
= MAX (BIGGEST_ALIGNMENT
, rli
->record_align
);
1155 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
1156 actual_align
= (BITS_PER_UNIT
1157 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
1158 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
1160 actual_align
= DECL_OFFSET_ALIGN (field
);
1161 /* ACTUAL_ALIGN is still the actual alignment *within the record* .
1162 store / extract bit field operations will check the alignment of the
1163 record against the mode of bit fields. */
1165 if (known_align
!= actual_align
)
1166 layout_decl (field
, actual_align
);
1168 if (rli
->prev_field
== NULL
&& DECL_BIT_FIELD_TYPE (field
))
1169 rli
->prev_field
= field
;
1171 /* Now add size of this field to the size of the record. If the size is
1172 not constant, treat the field as being a multiple of bytes and just
1173 adjust the offset, resetting the bit position. Otherwise, apportion the
1174 size amongst the bit position and offset. First handle the case of an
1175 unspecified size, which can happen when we have an invalid nested struct
1176 definition, such as struct j { struct j { int i; } }. The error message
1177 is printed in finish_struct. */
1178 if (DECL_SIZE (field
) == 0)
1180 else if (TREE_CODE (DECL_SIZE (field
)) != INTEGER_CST
1181 || TREE_CONSTANT_OVERFLOW (DECL_SIZE (field
)))
1184 = size_binop (PLUS_EXPR
, rli
->offset
,
1185 fold_convert (sizetype
,
1186 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1187 bitsize_unit_node
)));
1189 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1190 rli
->bitpos
= bitsize_zero_node
;
1191 rli
->offset_align
= MIN (rli
->offset_align
, desired_align
);
1193 else if (targetm
.ms_bitfield_layout_p (rli
->t
))
1195 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1197 /* If we ended a bitfield before the full length of the type then
1198 pad the struct out to the full length of the last type. */
1199 if ((TREE_CHAIN (field
) == NULL
1200 || TREE_CODE (TREE_CHAIN (field
)) != FIELD_DECL
)
1201 && DECL_BIT_FIELD_TYPE (field
)
1202 && !integer_zerop (DECL_SIZE (field
)))
1203 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
,
1204 bitsize_int (rli
->remaining_in_alignment
));
1206 normalize_rli (rli
);
1210 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1211 normalize_rli (rli
);
1215 /* Assuming that all the fields have been laid out, this function uses
1216 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1217 indicated by RLI. */
1220 finalize_record_size (record_layout_info rli
)
1222 tree unpadded_size
, unpadded_size_unit
;
1224 /* Now we want just byte and bit offsets, so set the offset alignment
1225 to be a byte and then normalize. */
1226 rli
->offset_align
= BITS_PER_UNIT
;
1227 normalize_rli (rli
);
1229 /* Determine the desired alignment. */
1230 #ifdef ROUND_TYPE_ALIGN
1231 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
1234 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
1237 /* Compute the size so far. Be sure to allow for extra bits in the
1238 size in bytes. We have guaranteed above that it will be no more
1239 than a single byte. */
1240 unpadded_size
= rli_size_so_far (rli
);
1241 unpadded_size_unit
= rli_size_unit_so_far (rli
);
1242 if (! integer_zerop (rli
->bitpos
))
1244 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
1246 /* Round the size up to be a multiple of the required alignment. */
1247 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
1248 TYPE_SIZE_UNIT (rli
->t
)
1249 = round_up (unpadded_size_unit
, TYPE_ALIGN_UNIT (rli
->t
));
1251 if (TREE_CONSTANT (unpadded_size
)
1252 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0)
1253 warning (OPT_Wpadded
, "padding struct size to alignment boundary");
1255 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
1256 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
1257 && TREE_CONSTANT (unpadded_size
))
1261 #ifdef ROUND_TYPE_ALIGN
1263 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1265 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1268 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
1269 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
1271 TYPE_PACKED (rli
->t
) = 0;
1273 if (TYPE_NAME (rli
->t
))
1277 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1278 name
= IDENTIFIER_POINTER (TYPE_NAME (rli
->t
));
1280 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli
->t
)));
1282 if (STRICT_ALIGNMENT
)
1283 warning (OPT_Wpacked
, "packed attribute causes inefficient "
1284 "alignment for %qs", name
);
1286 warning (OPT_Wpacked
,
1287 "packed attribute is unnecessary for %qs", name
);
1291 if (STRICT_ALIGNMENT
)
1292 warning (OPT_Wpacked
,
1293 "packed attribute causes inefficient alignment");
1295 warning (OPT_Wpacked
, "packed attribute is unnecessary");
1301 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1304 compute_record_mode (tree type
)
1307 enum machine_mode mode
= VOIDmode
;
1309 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1310 However, if possible, we use a mode that fits in a register
1311 instead, in order to allow for better optimization down the
1313 TYPE_MODE (type
) = BLKmode
;
1315 if (! host_integerp (TYPE_SIZE (type
), 1))
1318 /* A record which has any BLKmode members must itself be
1319 BLKmode; it can't go in a register. Unless the member is
1320 BLKmode only because it isn't aligned. */
1321 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1323 if (TREE_CODE (field
) != FIELD_DECL
)
1326 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1327 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1328 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
))
1329 && !(TYPE_SIZE (TREE_TYPE (field
)) != 0
1330 && integer_zerop (TYPE_SIZE (TREE_TYPE (field
)))))
1331 || ! host_integerp (bit_position (field
), 1)
1332 || DECL_SIZE (field
) == 0
1333 || ! host_integerp (DECL_SIZE (field
), 1))
1336 /* If this field is the whole struct, remember its mode so
1337 that, say, we can put a double in a class into a DF
1338 register instead of forcing it to live in the stack. */
1339 if (simple_cst_equal (TYPE_SIZE (type
), DECL_SIZE (field
)))
1340 mode
= DECL_MODE (field
);
1342 #ifdef MEMBER_TYPE_FORCES_BLK
1343 /* With some targets, eg. c4x, it is sub-optimal
1344 to access an aligned BLKmode structure as a scalar. */
1346 if (MEMBER_TYPE_FORCES_BLK (field
, mode
))
1348 #endif /* MEMBER_TYPE_FORCES_BLK */
1351 /* If we only have one real field; use its mode if that mode's size
1352 matches the type's size. This only applies to RECORD_TYPE. This
1353 does not apply to unions. */
1354 if (TREE_CODE (type
) == RECORD_TYPE
&& mode
!= VOIDmode
1355 && host_integerp (TYPE_SIZE (type
), 1)
1356 && GET_MODE_BITSIZE (mode
) == TREE_INT_CST_LOW (TYPE_SIZE (type
)))
1357 TYPE_MODE (type
) = mode
;
1359 TYPE_MODE (type
) = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1361 /* If structure's known alignment is less than what the scalar
1362 mode would need, and it matters, then stick with BLKmode. */
1363 if (TYPE_MODE (type
) != BLKmode
1365 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1366 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1368 /* If this is the only reason this type is BLKmode, then
1369 don't force containing types to be BLKmode. */
1370 TYPE_NO_FORCE_BLK (type
) = 1;
1371 TYPE_MODE (type
) = BLKmode
;
1375 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1379 finalize_type_size (tree type
)
1381 /* Normally, use the alignment corresponding to the mode chosen.
1382 However, where strict alignment is not required, avoid
1383 over-aligning structures, since most compilers do not do this
1386 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1387 && (STRICT_ALIGNMENT
1388 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1389 && TREE_CODE (type
) != QUAL_UNION_TYPE
1390 && TREE_CODE (type
) != ARRAY_TYPE
)))
1392 unsigned mode_align
= GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1394 /* Don't override a larger alignment requirement coming from a user
1395 alignment of one of the fields. */
1396 if (mode_align
>= TYPE_ALIGN (type
))
1398 TYPE_ALIGN (type
) = mode_align
;
1399 TYPE_USER_ALIGN (type
) = 0;
1403 /* Do machine-dependent extra alignment. */
1404 #ifdef ROUND_TYPE_ALIGN
1406 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1409 /* If we failed to find a simple way to calculate the unit size
1410 of the type, find it by division. */
1411 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1412 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1413 result will fit in sizetype. We will get more efficient code using
1414 sizetype, so we force a conversion. */
1415 TYPE_SIZE_UNIT (type
)
1416 = fold_convert (sizetype
,
1417 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1418 bitsize_unit_node
));
1420 if (TYPE_SIZE (type
) != 0)
1422 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1423 TYPE_SIZE_UNIT (type
) = round_up (TYPE_SIZE_UNIT (type
),
1424 TYPE_ALIGN_UNIT (type
));
1427 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1428 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1429 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1430 if (TYPE_SIZE_UNIT (type
) != 0
1431 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1432 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1434 /* Also layout any other variants of the type. */
1435 if (TYPE_NEXT_VARIANT (type
)
1436 || type
!= TYPE_MAIN_VARIANT (type
))
1439 /* Record layout info of this variant. */
1440 tree size
= TYPE_SIZE (type
);
1441 tree size_unit
= TYPE_SIZE_UNIT (type
);
1442 unsigned int align
= TYPE_ALIGN (type
);
1443 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1444 enum machine_mode mode
= TYPE_MODE (type
);
1446 /* Copy it into all variants. */
1447 for (variant
= TYPE_MAIN_VARIANT (type
);
1449 variant
= TYPE_NEXT_VARIANT (variant
))
1451 TYPE_SIZE (variant
) = size
;
1452 TYPE_SIZE_UNIT (variant
) = size_unit
;
1453 TYPE_ALIGN (variant
) = align
;
1454 TYPE_USER_ALIGN (variant
) = user_align
;
1455 TYPE_MODE (variant
) = mode
;
1460 /* Do all of the work required to layout the type indicated by RLI,
1461 once the fields have been laid out. This function will call `free'
1462 for RLI, unless FREE_P is false. Passing a value other than false
1463 for FREE_P is bad practice; this option only exists to support the
1467 finish_record_layout (record_layout_info rli
, int free_p
)
1469 /* Compute the final size. */
1470 finalize_record_size (rli
);
1472 /* Compute the TYPE_MODE for the record. */
1473 compute_record_mode (rli
->t
);
1475 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1476 finalize_type_size (rli
->t
);
1478 /* Lay out any static members. This is done now because their type
1479 may use the record's type. */
1480 while (rli
->pending_statics
)
1482 layout_decl (TREE_VALUE (rli
->pending_statics
), 0);
1483 rli
->pending_statics
= TREE_CHAIN (rli
->pending_statics
);
1492 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1493 NAME, its fields are chained in reverse on FIELDS.
1495 If ALIGN_TYPE is non-null, it is given the same alignment as
1499 finish_builtin_struct (tree type
, const char *name
, tree fields
,
1504 for (tail
= NULL_TREE
; fields
; tail
= fields
, fields
= next
)
1506 DECL_FIELD_CONTEXT (fields
) = type
;
1507 next
= TREE_CHAIN (fields
);
1508 TREE_CHAIN (fields
) = tail
;
1510 TYPE_FIELDS (type
) = tail
;
1514 TYPE_ALIGN (type
) = TYPE_ALIGN (align_type
);
1515 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (align_type
);
1519 #if 0 /* not yet, should get fixed properly later */
1520 TYPE_NAME (type
) = make_type_decl (get_identifier (name
), type
);
1522 TYPE_NAME (type
) = build_decl (TYPE_DECL
, get_identifier (name
), type
);
1524 TYPE_STUB_DECL (type
) = TYPE_NAME (type
);
1525 layout_decl (TYPE_NAME (type
), 0);
1528 /* Calculate the mode, size, and alignment for TYPE.
1529 For an array type, calculate the element separation as well.
1530 Record TYPE on the chain of permanent or temporary types
1531 so that dbxout will find out about it.
1533 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1534 layout_type does nothing on such a type.
1536 If the type is incomplete, its TYPE_SIZE remains zero. */
1539 layout_type (tree type
)
1543 if (type
== error_mark_node
)
1546 /* Do nothing if type has been laid out before. */
1547 if (TYPE_SIZE (type
))
1550 switch (TREE_CODE (type
))
1553 /* This kind of type is the responsibility
1554 of the language-specific code. */
1557 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1558 if (TYPE_PRECISION (type
) == 0)
1559 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1561 /* ... fall through ... */
1565 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1566 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1567 TYPE_UNSIGNED (type
) = 1;
1569 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
1571 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1572 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1576 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
1577 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1578 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1582 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1584 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1585 (TREE_CODE (TREE_TYPE (type
)) == REAL_TYPE
1586 ? MODE_COMPLEX_FLOAT
: MODE_COMPLEX_INT
),
1588 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1589 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1594 int nunits
= TYPE_VECTOR_SUBPARTS (type
);
1595 tree nunits_tree
= build_int_cst (NULL_TREE
, nunits
);
1596 tree innertype
= TREE_TYPE (type
);
1598 gcc_assert (!(nunits
& (nunits
- 1)));
1600 /* Find an appropriate mode for the vector type. */
1601 if (TYPE_MODE (type
) == VOIDmode
)
1603 enum machine_mode innermode
= TYPE_MODE (innertype
);
1604 enum machine_mode mode
;
1606 /* First, look for a supported vector type. */
1607 if (SCALAR_FLOAT_MODE_P (innermode
))
1608 mode
= MIN_MODE_VECTOR_FLOAT
;
1610 mode
= MIN_MODE_VECTOR_INT
;
1612 for (; mode
!= VOIDmode
; mode
= GET_MODE_WIDER_MODE (mode
))
1613 if (GET_MODE_NUNITS (mode
) == nunits
1614 && GET_MODE_INNER (mode
) == innermode
1615 && targetm
.vector_mode_supported_p (mode
))
1618 /* For integers, try mapping it to a same-sized scalar mode. */
1619 if (mode
== VOIDmode
1620 && GET_MODE_CLASS (innermode
) == MODE_INT
)
1621 mode
= mode_for_size (nunits
* GET_MODE_BITSIZE (innermode
),
1624 if (mode
== VOIDmode
|| !have_regs_of_mode
[mode
])
1625 TYPE_MODE (type
) = BLKmode
;
1627 TYPE_MODE (type
) = mode
;
1630 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1631 TYPE_SIZE_UNIT (type
) = int_const_binop (MULT_EXPR
,
1632 TYPE_SIZE_UNIT (innertype
),
1634 TYPE_SIZE (type
) = int_const_binop (MULT_EXPR
, TYPE_SIZE (innertype
),
1637 /* Always naturally align vectors. This prevents ABI changes
1638 depending on whether or not native vector modes are supported. */
1639 TYPE_ALIGN (type
) = tree_low_cst (TYPE_SIZE (type
), 0);
1644 /* This is an incomplete type and so doesn't have a size. */
1645 TYPE_ALIGN (type
) = 1;
1646 TYPE_USER_ALIGN (type
) = 0;
1647 TYPE_MODE (type
) = VOIDmode
;
1651 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1652 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1653 /* A pointer might be MODE_PARTIAL_INT,
1654 but ptrdiff_t must be integral. */
1655 TYPE_MODE (type
) = mode_for_size (POINTER_SIZE
, MODE_INT
, 0);
1660 /* It's hard to see what the mode and size of a function ought to
1661 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1662 make it consistent with that. */
1663 TYPE_MODE (type
) = mode_for_size (FUNCTION_BOUNDARY
, MODE_INT
, 0);
1664 TYPE_SIZE (type
) = bitsize_int (FUNCTION_BOUNDARY
);
1665 TYPE_SIZE_UNIT (type
) = size_int (FUNCTION_BOUNDARY
/ BITS_PER_UNIT
);
1669 case REFERENCE_TYPE
:
1672 enum machine_mode mode
= ((TREE_CODE (type
) == REFERENCE_TYPE
1673 && reference_types_internal
)
1674 ? Pmode
: TYPE_MODE (type
));
1676 int nbits
= GET_MODE_BITSIZE (mode
);
1678 TYPE_SIZE (type
) = bitsize_int (nbits
);
1679 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (mode
));
1680 TYPE_UNSIGNED (type
) = 1;
1681 TYPE_PRECISION (type
) = nbits
;
1687 tree index
= TYPE_DOMAIN (type
);
1688 tree element
= TREE_TYPE (type
);
1690 build_pointer_type (element
);
1692 /* We need to know both bounds in order to compute the size. */
1693 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1694 && TYPE_SIZE (element
))
1696 tree ub
= TYPE_MAX_VALUE (index
);
1697 tree lb
= TYPE_MIN_VALUE (index
);
1701 /* The initial subtraction should happen in the original type so
1702 that (possible) negative values are handled appropriately. */
1703 length
= size_binop (PLUS_EXPR
, size_one_node
,
1704 fold_convert (sizetype
,
1705 fold_build2 (MINUS_EXPR
,
1709 /* Special handling for arrays of bits (for Chill). */
1710 element_size
= TYPE_SIZE (element
);
1711 if (TYPE_PACKED (type
) && INTEGRAL_TYPE_P (element
)
1712 && (integer_zerop (TYPE_MAX_VALUE (element
))
1713 || integer_onep (TYPE_MAX_VALUE (element
)))
1714 && host_integerp (TYPE_MIN_VALUE (element
), 1))
1716 HOST_WIDE_INT maxvalue
1717 = tree_low_cst (TYPE_MAX_VALUE (element
), 1);
1718 HOST_WIDE_INT minvalue
1719 = tree_low_cst (TYPE_MIN_VALUE (element
), 1);
1721 if (maxvalue
- minvalue
== 1
1722 && (maxvalue
== 1 || maxvalue
== 0))
1723 element_size
= integer_one_node
;
1726 /* If neither bound is a constant and sizetype is signed, make
1727 sure the size is never negative. We should really do this
1728 if *either* bound is non-constant, but this is the best
1729 compromise between C and Ada. */
1730 if (!TYPE_UNSIGNED (sizetype
)
1731 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
1732 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
1733 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
1735 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1736 fold_convert (bitsizetype
,
1739 /* If we know the size of the element, calculate the total
1740 size directly, rather than do some division thing below.
1741 This optimization helps Fortran assumed-size arrays
1742 (where the size of the array is determined at runtime)
1744 Note that we can't do this in the case where the size of
1745 the elements is one bit since TYPE_SIZE_UNIT cannot be
1746 set correctly in that case. */
1747 if (TYPE_SIZE_UNIT (element
) != 0 && ! integer_onep (element_size
))
1748 TYPE_SIZE_UNIT (type
)
1749 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1752 /* Now round the alignment and size,
1753 using machine-dependent criteria if any. */
1755 #ifdef ROUND_TYPE_ALIGN
1757 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1759 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1761 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (element
);
1762 TYPE_MODE (type
) = BLKmode
;
1763 if (TYPE_SIZE (type
) != 0
1764 #ifdef MEMBER_TYPE_FORCES_BLK
1765 && ! MEMBER_TYPE_FORCES_BLK (type
, VOIDmode
)
1767 /* BLKmode elements force BLKmode aggregate;
1768 else extract/store fields may lose. */
1769 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
1770 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
1772 /* One-element arrays get the component type's mode. */
1773 if (simple_cst_equal (TYPE_SIZE (type
),
1774 TYPE_SIZE (TREE_TYPE (type
))))
1775 TYPE_MODE (type
) = TYPE_MODE (TREE_TYPE (type
));
1778 = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1780 if (TYPE_MODE (type
) != BLKmode
1781 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
1782 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
))
1783 && TYPE_MODE (type
) != BLKmode
)
1785 TYPE_NO_FORCE_BLK (type
) = 1;
1786 TYPE_MODE (type
) = BLKmode
;
1789 /* When the element size is constant, check that it is at least as
1790 large as the element alignment. */
1791 if (TYPE_SIZE_UNIT (element
)
1792 && TREE_CODE (TYPE_SIZE_UNIT (element
)) == INTEGER_CST
1793 /* If TYPE_SIZE_UNIT overflowed, then it is certainly larger than
1795 && !TREE_CONSTANT_OVERFLOW (TYPE_SIZE_UNIT (element
))
1796 && !integer_zerop (TYPE_SIZE_UNIT (element
))
1797 && compare_tree_int (TYPE_SIZE_UNIT (element
),
1798 TYPE_ALIGN_UNIT (element
)) < 0)
1799 error ("alignment of array elements is greater than element size");
1805 case QUAL_UNION_TYPE
:
1808 record_layout_info rli
;
1810 /* Initialize the layout information. */
1811 rli
= start_record_layout (type
);
1813 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1814 in the reverse order in building the COND_EXPR that denotes
1815 its size. We reverse them again later. */
1816 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1817 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1819 /* Place all the fields. */
1820 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1821 place_field (rli
, field
);
1823 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1824 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1826 if (lang_adjust_rli
)
1827 (*lang_adjust_rli
) (rli
);
1829 /* Finish laying out the record. */
1830 finish_record_layout (rli
, /*free_p=*/true);
1838 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1839 records and unions, finish_record_layout already called this
1841 if (TREE_CODE (type
) != RECORD_TYPE
1842 && TREE_CODE (type
) != UNION_TYPE
1843 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
1844 finalize_type_size (type
);
1846 /* If an alias set has been set for this aggregate when it was incomplete,
1847 force it into alias set 0.
1848 This is too conservative, but we cannot call record_component_aliases
1849 here because some frontends still change the aggregates after
1851 if (AGGREGATE_TYPE_P (type
) && TYPE_ALIAS_SET_KNOWN_P (type
))
1852 TYPE_ALIAS_SET (type
) = 0;
1855 /* Create and return a type for signed integers of PRECISION bits. */
1858 make_signed_type (int precision
)
1860 tree type
= make_node (INTEGER_TYPE
);
1862 TYPE_PRECISION (type
) = precision
;
1864 fixup_signed_type (type
);
1868 /* Create and return a type for unsigned integers of PRECISION bits. */
1871 make_unsigned_type (int precision
)
1873 tree type
= make_node (INTEGER_TYPE
);
1875 TYPE_PRECISION (type
) = precision
;
1877 fixup_unsigned_type (type
);
1881 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1882 value to enable integer types to be created. */
1885 initialize_sizetypes (bool signed_p
)
1887 tree t
= make_node (INTEGER_TYPE
);
1888 int precision
= GET_MODE_BITSIZE (SImode
);
1890 TYPE_MODE (t
) = SImode
;
1891 TYPE_ALIGN (t
) = GET_MODE_ALIGNMENT (SImode
);
1892 TYPE_USER_ALIGN (t
) = 0;
1893 TYPE_IS_SIZETYPE (t
) = 1;
1894 TYPE_UNSIGNED (t
) = !signed_p
;
1895 TYPE_SIZE (t
) = build_int_cst (t
, precision
);
1896 TYPE_SIZE_UNIT (t
) = build_int_cst (t
, GET_MODE_SIZE (SImode
));
1897 TYPE_PRECISION (t
) = precision
;
1899 /* Set TYPE_MIN_VALUE and TYPE_MAX_VALUE. */
1900 set_min_and_max_values_for_integral_type (t
, precision
, !signed_p
);
1903 bitsizetype
= build_distinct_type_copy (t
);
1906 /* Make sizetype a version of TYPE, and initialize *sizetype
1907 accordingly. We do this by overwriting the stub sizetype and
1908 bitsizetype nodes created by initialize_sizetypes. This makes sure
1909 that (a) anything stubby about them no longer exists, (b) any
1910 INTEGER_CSTs created with such a type, remain valid. */
1913 set_sizetype (tree type
)
1915 int oprecision
= TYPE_PRECISION (type
);
1916 /* The *bitsizetype types use a precision that avoids overflows when
1917 calculating signed sizes / offsets in bits. However, when
1918 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1920 int precision
= MIN (oprecision
+ BITS_PER_UNIT_LOG
+ 1,
1921 2 * HOST_BITS_PER_WIDE_INT
);
1924 gcc_assert (TYPE_UNSIGNED (type
) == TYPE_UNSIGNED (sizetype
));
1926 t
= build_distinct_type_copy (type
);
1927 /* We do want to use sizetype's cache, as we will be replacing that
1929 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (sizetype
);
1930 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (sizetype
);
1931 TREE_TYPE (TYPE_CACHED_VALUES (t
)) = type
;
1932 TYPE_UID (t
) = TYPE_UID (sizetype
);
1933 TYPE_IS_SIZETYPE (t
) = 1;
1935 /* Replace our original stub sizetype. */
1936 memcpy (sizetype
, t
, tree_size (sizetype
));
1937 TYPE_MAIN_VARIANT (sizetype
) = sizetype
;
1939 t
= make_node (INTEGER_TYPE
);
1940 TYPE_NAME (t
) = get_identifier ("bit_size_type");
1941 /* We do want to use bitsizetype's cache, as we will be replacing that
1943 TYPE_CACHED_VALUES (t
) = TYPE_CACHED_VALUES (bitsizetype
);
1944 TYPE_CACHED_VALUES_P (t
) = TYPE_CACHED_VALUES_P (bitsizetype
);
1945 TYPE_PRECISION (t
) = precision
;
1946 TYPE_UID (t
) = TYPE_UID (bitsizetype
);
1947 TYPE_IS_SIZETYPE (t
) = 1;
1949 /* Replace our original stub bitsizetype. */
1950 memcpy (bitsizetype
, t
, tree_size (bitsizetype
));
1951 TYPE_MAIN_VARIANT (bitsizetype
) = bitsizetype
;
1953 if (TYPE_UNSIGNED (type
))
1955 fixup_unsigned_type (bitsizetype
);
1956 ssizetype
= build_distinct_type_copy (make_signed_type (oprecision
));
1957 TYPE_IS_SIZETYPE (ssizetype
) = 1;
1958 sbitsizetype
= build_distinct_type_copy (make_signed_type (precision
));
1959 TYPE_IS_SIZETYPE (sbitsizetype
) = 1;
1963 fixup_signed_type (bitsizetype
);
1964 ssizetype
= sizetype
;
1965 sbitsizetype
= bitsizetype
;
1968 /* If SIZETYPE is unsigned, we need to fix TYPE_MAX_VALUE so that
1969 it is sign extended in a way consistent with force_fit_type. */
1970 if (TYPE_UNSIGNED (type
))
1972 tree orig_max
, new_max
;
1974 orig_max
= TYPE_MAX_VALUE (sizetype
);
1976 /* Build a new node with the same values, but a different type. */
1977 new_max
= build_int_cst_wide (sizetype
,
1978 TREE_INT_CST_LOW (orig_max
),
1979 TREE_INT_CST_HIGH (orig_max
));
1981 /* Now sign extend it using force_fit_type to ensure
1983 new_max
= force_fit_type (new_max
, 0, 0, 0);
1984 TYPE_MAX_VALUE (sizetype
) = new_max
;
1988 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE
1989 or BOOLEAN_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1990 for TYPE, based on the PRECISION and whether or not the TYPE
1991 IS_UNSIGNED. PRECISION need not correspond to a width supported
1992 natively by the hardware; for example, on a machine with 8-bit,
1993 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1997 set_min_and_max_values_for_integral_type (tree type
,
2006 min_value
= build_int_cst (type
, 0);
2008 = build_int_cst_wide (type
, precision
- HOST_BITS_PER_WIDE_INT
>= 0
2010 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
2011 precision
- HOST_BITS_PER_WIDE_INT
> 0
2012 ? ((unsigned HOST_WIDE_INT
) ~0
2013 >> (HOST_BITS_PER_WIDE_INT
2014 - (precision
- HOST_BITS_PER_WIDE_INT
)))
2020 = build_int_cst_wide (type
,
2021 (precision
- HOST_BITS_PER_WIDE_INT
> 0
2023 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
2024 (((HOST_WIDE_INT
) (-1)
2025 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
2026 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
2029 = build_int_cst_wide (type
,
2030 (precision
- HOST_BITS_PER_WIDE_INT
> 0
2032 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
2033 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
2034 ? (((HOST_WIDE_INT
) 1
2035 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
2039 TYPE_MIN_VALUE (type
) = min_value
;
2040 TYPE_MAX_VALUE (type
) = max_value
;
2043 /* Set the extreme values of TYPE based on its precision in bits,
2044 then lay it out. Used when make_signed_type won't do
2045 because the tree code is not INTEGER_TYPE.
2046 E.g. for Pascal, when the -fsigned-char option is given. */
2049 fixup_signed_type (tree type
)
2051 int precision
= TYPE_PRECISION (type
);
2053 /* We can not represent properly constants greater then
2054 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2055 as they are used by i386 vector extensions and friends. */
2056 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2057 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2059 set_min_and_max_values_for_integral_type (type
, precision
,
2060 /*is_unsigned=*/false);
2062 /* Lay out the type: set its alignment, size, etc. */
2066 /* Set the extreme values of TYPE based on its precision in bits,
2067 then lay it out. This is used both in `make_unsigned_type'
2068 and for enumeral types. */
2071 fixup_unsigned_type (tree type
)
2073 int precision
= TYPE_PRECISION (type
);
2075 /* We can not represent properly constants greater then
2076 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2077 as they are used by i386 vector extensions and friends. */
2078 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2079 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2081 TYPE_UNSIGNED (type
) = 1;
2083 set_min_and_max_values_for_integral_type (type
, precision
,
2084 /*is_unsigned=*/true);
2086 /* Lay out the type: set its alignment, size, etc. */
2090 /* Find the best machine mode to use when referencing a bit field of length
2091 BITSIZE bits starting at BITPOS.
2093 The underlying object is known to be aligned to a boundary of ALIGN bits.
2094 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2095 larger than LARGEST_MODE (usually SImode).
2097 If no mode meets all these conditions, we return VOIDmode.
2099 If VOLATILEP is false and SLOW_BYTE_ACCESS is false, we return the
2100 smallest mode meeting these conditions.
2102 If VOLATILEP is false and SLOW_BYTE_ACCESS is true, we return the
2103 largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2106 If VOLATILEP is true the narrow_volatile_bitfields target hook is used to
2107 decide which of the above modes should be used. */
2110 get_best_mode (int bitsize
, int bitpos
, unsigned int align
,
2111 enum machine_mode largest_mode
, int volatilep
)
2113 enum machine_mode mode
;
2114 unsigned int unit
= 0;
2116 /* Find the narrowest integer mode that contains the bit field. */
2117 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
2118 mode
= GET_MODE_WIDER_MODE (mode
))
2120 unit
= GET_MODE_BITSIZE (mode
);
2121 if ((bitpos
% unit
) + bitsize
<= unit
)
2125 if (mode
== VOIDmode
2126 /* It is tempting to omit the following line
2127 if STRICT_ALIGNMENT is true.
2128 But that is incorrect, since if the bitfield uses part of 3 bytes
2129 and we use a 4-byte mode, we could get a spurious segv
2130 if the extra 4th byte is past the end of memory.
2131 (Though at least one Unix compiler ignores this problem:
2132 that on the Sequent 386 machine. */
2133 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
2134 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
2137 if ((SLOW_BYTE_ACCESS
&& ! volatilep
)
2138 || (volatilep
&& !targetm
.narrow_volatile_bitfield()))
2140 enum machine_mode wide_mode
= VOIDmode
, tmode
;
2142 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
2143 tmode
= GET_MODE_WIDER_MODE (tmode
))
2145 unit
= GET_MODE_BITSIZE (tmode
);
2146 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
2147 && unit
<= BITS_PER_WORD
2148 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
2149 && (largest_mode
== VOIDmode
2150 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
2154 if (wide_mode
!= VOIDmode
)
2161 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2162 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2165 get_mode_bounds (enum machine_mode mode
, int sign
,
2166 enum machine_mode target_mode
,
2167 rtx
*mmin
, rtx
*mmax
)
2169 unsigned size
= GET_MODE_BITSIZE (mode
);
2170 unsigned HOST_WIDE_INT min_val
, max_val
;
2172 gcc_assert (size
<= HOST_BITS_PER_WIDE_INT
);
2176 min_val
= -((unsigned HOST_WIDE_INT
) 1 << (size
- 1));
2177 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1)) - 1;
2182 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1) << 1) - 1;
2185 *mmin
= gen_int_mode (min_val
, target_mode
);
2186 *mmax
= gen_int_mode (max_val
, target_mode
);
2189 #include "gt-stor-layout.h"