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 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
25 #include "coretypes.h"
36 #include "langhooks.h"
38 /* Set to one when set_sizetype has been called. */
39 static int sizetype_set
;
41 /* List of types created before set_sizetype has been called. We do not
42 make this a GGC root since we want these nodes to be reclaimed. */
43 static tree early_type_list
;
45 /* Data type for the expressions representing sizes of data types.
46 It is the first integer type laid out. */
47 tree sizetype_tab
[(int) TYPE_KIND_LAST
];
49 /* If nonzero, this is an upper limit on alignment of structure fields.
50 The value is measured in bits. */
51 unsigned int maximum_field_alignment
;
53 /* If nonzero, the alignment of a bitstring or (power-)set value, in bits.
54 May be overridden by front-ends. */
55 unsigned int set_alignment
= 0;
57 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be
58 allocated in Pmode, not ptr_mode. Set only by internal_reference_types
59 called only by a front end. */
60 static int reference_types_internal
= 0;
62 static void finalize_record_size (record_layout_info
);
63 static void finalize_type_size (tree
);
64 static void place_union_field (record_layout_info
, tree
);
65 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
66 static int excess_unit_span (HOST_WIDE_INT
, HOST_WIDE_INT
, HOST_WIDE_INT
,
69 static unsigned int update_alignment_for_field (record_layout_info
, tree
,
71 extern void debug_rli (record_layout_info
);
73 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
75 static GTY(()) tree pending_sizes
;
77 /* Nonzero means cannot safely call expand_expr now,
78 so put variable sizes onto `pending_sizes' instead. */
80 int immediate_size_expand
;
82 /* Show that REFERENCE_TYPES are internal and should be Pmode. Called only
86 internal_reference_types (void)
88 reference_types_internal
= 1;
91 /* Get a list of all the objects put on the pending sizes list. */
94 get_pending_sizes (void)
96 tree chain
= pending_sizes
;
99 /* Put each SAVE_EXPR into the current function. */
100 for (t
= chain
; t
; t
= TREE_CHAIN (t
))
101 SAVE_EXPR_CONTEXT (TREE_VALUE (t
)) = current_function_decl
;
107 /* Return nonzero if EXPR is present on the pending sizes list. */
110 is_pending_size (tree expr
)
114 for (t
= pending_sizes
; t
; t
= TREE_CHAIN (t
))
115 if (TREE_VALUE (t
) == expr
)
120 /* Add EXPR to the pending sizes list. */
123 put_pending_size (tree expr
)
125 /* Strip any simple arithmetic from EXPR to see if it has an underlying
127 expr
= skip_simple_arithmetic (expr
);
129 if (TREE_CODE (expr
) == SAVE_EXPR
)
130 pending_sizes
= tree_cons (NULL_TREE
, expr
, pending_sizes
);
133 /* Put a chain of objects into the pending sizes list, which must be
137 put_pending_sizes (tree chain
)
142 pending_sizes
= chain
;
145 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
146 to serve as the actual size-expression for a type or decl. */
149 variable_size (tree size
)
153 /* If the language-processor is to take responsibility for variable-sized
154 items (e.g., languages which have elaboration procedures like Ada),
155 just return SIZE unchanged. Likewise for self-referential sizes and
157 if (TREE_CONSTANT (size
)
158 || (*lang_hooks
.decls
.global_bindings_p
) () < 0
159 || CONTAINS_PLACEHOLDER_P (size
))
162 if (TREE_CODE (size
) == MINUS_EXPR
&& integer_onep (TREE_OPERAND (size
, 1)))
163 /* If this is the upper bound of a C array, leave the minus 1 outside
164 the SAVE_EXPR so it can be folded away. */
165 TREE_OPERAND (size
, 0) = save
= save_expr (TREE_OPERAND (size
, 0));
167 size
= save
= save_expr (size
);
169 /* If an array with a variable number of elements is declared, and
170 the elements require destruction, we will emit a cleanup for the
171 array. That cleanup is run both on normal exit from the block
172 and in the exception-handler for the block. Normally, when code
173 is used in both ordinary code and in an exception handler it is
174 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
175 not wish to do that here; the array-size is the same in both
177 if (TREE_CODE (save
) == SAVE_EXPR
)
178 SAVE_EXPR_PERSISTENT_P (save
) = 1;
180 if ((*lang_hooks
.decls
.global_bindings_p
) ())
182 if (TREE_CONSTANT (size
))
183 error ("type size can't be explicitly evaluated");
185 error ("variable-size type declared outside of any function");
187 return size_one_node
;
190 if (immediate_size_expand
)
191 expand_expr (save
, const0_rtx
, VOIDmode
, 0);
192 else if (cfun
!= 0 && cfun
->x_dont_save_pending_sizes_p
)
193 /* The front-end doesn't want us to keep a list of the expressions
194 that determine sizes for variable size objects. */
197 put_pending_size (save
);
202 #ifndef MAX_FIXED_MODE_SIZE
203 #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
206 /* Return the machine mode to use for a nonscalar of SIZE bits.
207 The mode must be in class CLASS, and have exactly that many bits.
208 If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
212 mode_for_size (unsigned int size
, enum mode_class
class, int limit
)
214 enum machine_mode mode
;
216 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
219 /* Get the first mode which has this size, in the specified class. */
220 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
221 mode
= GET_MODE_WIDER_MODE (mode
))
222 if (GET_MODE_BITSIZE (mode
) == size
)
228 /* Similar, except passed a tree node. */
231 mode_for_size_tree (tree size
, enum mode_class
class, int limit
)
233 if (TREE_CODE (size
) != INTEGER_CST
234 || TREE_OVERFLOW (size
)
235 /* What we really want to say here is that the size can fit in a
236 host integer, but we know there's no way we'd find a mode for
237 this many bits, so there's no point in doing the precise test. */
238 || compare_tree_int (size
, 1000) > 0)
241 return mode_for_size (tree_low_cst (size
, 1), class, limit
);
244 /* Similar, but never return BLKmode; return the narrowest mode that
245 contains at least the requested number of bits. */
248 smallest_mode_for_size (unsigned int size
, enum mode_class
class)
250 enum machine_mode mode
;
252 /* Get the first mode which has at least this size, in the
254 for (mode
= GET_CLASS_NARROWEST_MODE (class); mode
!= VOIDmode
;
255 mode
= GET_MODE_WIDER_MODE (mode
))
256 if (GET_MODE_BITSIZE (mode
) >= size
)
262 /* Find an integer mode of the exact same size, or BLKmode on failure. */
265 int_mode_for_mode (enum machine_mode mode
)
267 switch (GET_MODE_CLASS (mode
))
270 case MODE_PARTIAL_INT
:
273 case MODE_COMPLEX_INT
:
274 case MODE_COMPLEX_FLOAT
:
276 case MODE_VECTOR_INT
:
277 case MODE_VECTOR_FLOAT
:
278 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
285 /* ... fall through ... */
295 /* Return the alignment of MODE. This will be bounded by 1 and
296 BIGGEST_ALIGNMENT. */
299 get_mode_alignment (enum machine_mode mode
)
301 return MIN (BIGGEST_ALIGNMENT
, MAX (1, mode_base_align
[mode
]*BITS_PER_UNIT
));
304 /* Return the value of VALUE, rounded up to a multiple of DIVISOR.
305 This can only be applied to objects of a sizetype. */
308 round_up (tree value
, int divisor
)
310 tree arg
= size_int_type (divisor
, TREE_TYPE (value
));
312 return size_binop (MULT_EXPR
, size_binop (CEIL_DIV_EXPR
, value
, arg
), arg
);
315 /* Likewise, but round down. */
318 round_down (tree value
, int divisor
)
320 tree arg
= size_int_type (divisor
, TREE_TYPE (value
));
322 return size_binop (MULT_EXPR
, size_binop (FLOOR_DIV_EXPR
, value
, arg
), arg
);
325 /* Subroutine of layout_decl: Force alignment required for the data type.
326 But if the decl itself wants greater alignment, don't override that. */
329 do_type_align (tree type
, tree decl
)
331 if (TYPE_ALIGN (type
) > DECL_ALIGN (decl
))
333 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
334 if (TREE_CODE (decl
) == FIELD_DECL
)
335 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
339 /* Set the size, mode and alignment of a ..._DECL node.
340 TYPE_DECL does need this for C++.
341 Note that LABEL_DECL and CONST_DECL nodes do not need this,
342 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
343 Don't call layout_decl for them.
345 KNOWN_ALIGN is the amount of alignment we can assume this
346 decl has with no special effort. It is relevant only for FIELD_DECLs
347 and depends on the previous fields.
348 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
349 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
350 the record will be aligned to suit. */
353 layout_decl (tree decl
, unsigned int known_align
)
355 tree type
= TREE_TYPE (decl
);
356 enum tree_code code
= TREE_CODE (decl
);
359 if (code
== CONST_DECL
)
361 else if (code
!= VAR_DECL
&& code
!= PARM_DECL
&& code
!= RESULT_DECL
362 && code
!= TYPE_DECL
&& code
!= FIELD_DECL
)
365 rtl
= DECL_RTL_IF_SET (decl
);
367 if (type
== error_mark_node
)
368 type
= void_type_node
;
370 /* Usually the size and mode come from the data type without change,
371 however, the front-end may set the explicit width of the field, so its
372 size may not be the same as the size of its type. This happens with
373 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
374 also happens with other fields. For example, the C++ front-end creates
375 zero-sized fields corresponding to empty base classes, and depends on
376 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
377 size in bytes from the size in bits. If we have already set the mode,
378 don't set it again since we can be called twice for FIELD_DECLs. */
380 TREE_UNSIGNED (decl
) = TREE_UNSIGNED (type
);
381 if (DECL_MODE (decl
) == VOIDmode
)
382 DECL_MODE (decl
) = TYPE_MODE (type
);
384 if (DECL_SIZE (decl
) == 0)
386 DECL_SIZE (decl
) = TYPE_SIZE (type
);
387 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
389 else if (DECL_SIZE_UNIT (decl
) == 0)
390 DECL_SIZE_UNIT (decl
)
391 = convert (sizetype
, size_binop (CEIL_DIV_EXPR
, DECL_SIZE (decl
),
394 if (code
!= FIELD_DECL
)
395 /* For non-fields, update the alignment from the type. */
396 do_type_align (type
, decl
);
398 /* For fields, it's a bit more complicated... */
400 bool old_user_align
= DECL_USER_ALIGN (decl
);
402 if (DECL_BIT_FIELD (decl
))
404 DECL_BIT_FIELD_TYPE (decl
) = type
;
406 /* A zero-length bit-field affects the alignment of the next
408 if (integer_zerop (DECL_SIZE (decl
))
409 && ! DECL_PACKED (decl
)
410 && ! (*targetm
.ms_bitfield_layout_p
) (DECL_FIELD_CONTEXT (decl
)))
412 #ifdef PCC_BITFIELD_TYPE_MATTERS
413 if (PCC_BITFIELD_TYPE_MATTERS
)
414 do_type_align (type
, decl
);
418 #ifdef EMPTY_FIELD_BOUNDARY
419 if (EMPTY_FIELD_BOUNDARY
> DECL_ALIGN (decl
))
421 DECL_ALIGN (decl
) = EMPTY_FIELD_BOUNDARY
;
422 DECL_USER_ALIGN (decl
) = 0;
428 /* See if we can use an ordinary integer mode for a bit-field.
429 Conditions are: a fixed size that is correct for another mode
430 and occupying a complete byte or bytes on proper boundary. */
431 if (TYPE_SIZE (type
) != 0
432 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
433 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
)
435 enum machine_mode xmode
436 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
438 if (xmode
!= BLKmode
&& known_align
>= GET_MODE_ALIGNMENT (xmode
))
440 DECL_ALIGN (decl
) = MAX (GET_MODE_ALIGNMENT (xmode
),
442 DECL_MODE (decl
) = xmode
;
443 DECL_BIT_FIELD (decl
) = 0;
447 /* Turn off DECL_BIT_FIELD if we won't need it set. */
448 if (TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
449 && known_align
>= TYPE_ALIGN (type
)
450 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
))
451 DECL_BIT_FIELD (decl
) = 0;
453 else if (DECL_PACKED (decl
) && DECL_USER_ALIGN (decl
))
454 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
455 round up; we'll reduce it again below. We want packing to
456 supercede USER_ALIGN inherited from the type, but defer to
457 alignment explicitly specified on the field decl. */;
459 do_type_align (type
, decl
);
461 /* If the field is of variable size, we can't misalign it since we
462 have no way to make a temporary to align the result. But this
463 isn't an issue if the decl is not addressable. Likewise if it
466 Note that do_type_align may set DECL_USER_ALIGN, so we need to
467 check old_user_align instead. */
468 if (DECL_PACKED (decl
)
470 && (DECL_NONADDRESSABLE_P (decl
)
471 || DECL_SIZE_UNIT (decl
) == 0
472 || TREE_CODE (DECL_SIZE_UNIT (decl
)) == INTEGER_CST
))
473 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
475 /* Should this be controlled by DECL_USER_ALIGN, too? */
476 if (maximum_field_alignment
!= 0)
477 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), maximum_field_alignment
);
478 if (! DECL_USER_ALIGN (decl
))
480 /* Some targets (i.e. i386, VMS) limit struct field alignment
481 to a lower boundary than alignment of variables unless
482 it was overridden by attribute aligned. */
483 #ifdef BIGGEST_FIELD_ALIGNMENT
485 = MIN (DECL_ALIGN (decl
), (unsigned) BIGGEST_FIELD_ALIGNMENT
);
487 #ifdef ADJUST_FIELD_ALIGN
488 DECL_ALIGN (decl
) = ADJUST_FIELD_ALIGN (decl
, DECL_ALIGN (decl
));
493 /* Evaluate nonconstant size only once, either now or as soon as safe. */
494 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
495 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
496 if (DECL_SIZE_UNIT (decl
) != 0
497 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
498 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
500 /* If requested, warn about definitions of large data objects. */
502 && (code
== VAR_DECL
|| code
== PARM_DECL
)
503 && ! DECL_EXTERNAL (decl
))
505 tree size
= DECL_SIZE_UNIT (decl
);
507 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
508 && compare_tree_int (size
, larger_than_size
) > 0)
510 int size_as_int
= TREE_INT_CST_LOW (size
);
512 if (compare_tree_int (size
, size_as_int
) == 0)
513 warning ("%Jsize of '%D' is %d bytes", decl
, decl
, size_as_int
);
515 warning ("%Jsize of '%D' is larger than %d bytes",
516 decl
, decl
, larger_than_size
);
520 /* If the RTL was already set, update its mode and mem attributes. */
523 PUT_MODE (rtl
, DECL_MODE (decl
));
524 SET_DECL_RTL (decl
, 0);
525 set_mem_attributes (rtl
, decl
, 1);
526 SET_DECL_RTL (decl
, rtl
);
530 /* Hook for a front-end function that can modify the record layout as needed
531 immediately before it is finalized. */
533 void (*lang_adjust_rli
) (record_layout_info
) = 0;
536 set_lang_adjust_rli (void (*f
) (record_layout_info
))
541 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
542 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
543 is to be passed to all other layout functions for this record. It is the
544 responsibility of the caller to call `free' for the storage returned.
545 Note that garbage collection is not permitted until we finish laying
549 start_record_layout (tree t
)
551 record_layout_info rli
= xmalloc (sizeof (struct record_layout_info_s
));
555 /* If the type has a minimum specified alignment (via an attribute
556 declaration, for example) use it -- otherwise, start with a
557 one-byte alignment. */
558 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
559 rli
->unpacked_align
= rli
->record_align
;
560 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
562 #ifdef STRUCTURE_SIZE_BOUNDARY
563 /* Packed structures don't need to have minimum size. */
564 if (! TYPE_PACKED (t
))
565 rli
->record_align
= MAX (rli
->record_align
, (unsigned) STRUCTURE_SIZE_BOUNDARY
);
568 rli
->offset
= size_zero_node
;
569 rli
->bitpos
= bitsize_zero_node
;
571 rli
->pending_statics
= 0;
572 rli
->packed_maybe_necessary
= 0;
577 /* These four routines perform computations that convert between
578 the offset/bitpos forms and byte and bit offsets. */
581 bit_from_pos (tree offset
, tree bitpos
)
583 return size_binop (PLUS_EXPR
, bitpos
,
584 size_binop (MULT_EXPR
, convert (bitsizetype
, offset
),
589 byte_from_pos (tree offset
, tree bitpos
)
591 return size_binop (PLUS_EXPR
, offset
,
593 size_binop (TRUNC_DIV_EXPR
, bitpos
,
594 bitsize_unit_node
)));
598 pos_from_bit (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
,
601 *poffset
= size_binop (MULT_EXPR
,
603 size_binop (FLOOR_DIV_EXPR
, pos
,
604 bitsize_int (off_align
))),
605 size_int (off_align
/ BITS_PER_UNIT
));
606 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
609 /* Given a pointer to bit and byte offsets and an offset alignment,
610 normalize the offsets so they are within the alignment. */
613 normalize_offset (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
)
615 /* If the bit position is now larger than it should be, adjust it
617 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
619 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
620 bitsize_int (off_align
));
623 = size_binop (PLUS_EXPR
, *poffset
,
624 size_binop (MULT_EXPR
, convert (sizetype
, extra_aligns
),
625 size_int (off_align
/ BITS_PER_UNIT
)));
628 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
632 /* Print debugging information about the information in RLI. */
635 debug_rli (record_layout_info rli
)
637 print_node_brief (stderr
, "type", rli
->t
, 0);
638 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
639 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
641 fprintf (stderr
, "\naligns: rec = %u, unpack = %u, off = %u\n",
642 rli
->record_align
, rli
->unpacked_align
,
644 if (rli
->packed_maybe_necessary
)
645 fprintf (stderr
, "packed may be necessary\n");
647 if (rli
->pending_statics
)
649 fprintf (stderr
, "pending statics:\n");
650 debug_tree (rli
->pending_statics
);
654 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
655 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
658 normalize_rli (record_layout_info rli
)
660 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
663 /* Returns the size in bytes allocated so far. */
666 rli_size_unit_so_far (record_layout_info rli
)
668 return byte_from_pos (rli
->offset
, rli
->bitpos
);
671 /* Returns the size in bits allocated so far. */
674 rli_size_so_far (record_layout_info rli
)
676 return bit_from_pos (rli
->offset
, rli
->bitpos
);
679 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
680 the next available location is given by KNOWN_ALIGN. Update the
681 variable alignment fields in RLI, and return the alignment to give
685 update_alignment_for_field (record_layout_info rli
, tree field
,
686 unsigned int known_align
)
688 /* The alignment required for FIELD. */
689 unsigned int desired_align
;
690 /* The type of this field. */
691 tree type
= TREE_TYPE (field
);
692 /* True if the field was explicitly aligned by the user. */
696 /* Lay out the field so we know what alignment it needs. */
697 layout_decl (field
, known_align
);
698 desired_align
= DECL_ALIGN (field
);
699 user_align
= DECL_USER_ALIGN (field
);
701 is_bitfield
= (type
!= error_mark_node
702 && DECL_BIT_FIELD_TYPE (field
)
703 && ! integer_zerop (TYPE_SIZE (type
)));
705 /* Record must have at least as much alignment as any field.
706 Otherwise, the alignment of the field within the record is
708 if (is_bitfield
&& (* targetm
.ms_bitfield_layout_p
) (rli
->t
))
710 /* Here, the alignment of the underlying type of a bitfield can
711 affect the alignment of a record; even a zero-sized field
712 can do this. The alignment should be to the alignment of
713 the type, except that for zero-size bitfields this only
714 applies if there was an immediately prior, nonzero-size
715 bitfield. (That's the way it is, experimentally.) */
716 if (! integer_zerop (DECL_SIZE (field
))
717 ? ! DECL_PACKED (field
)
719 && DECL_BIT_FIELD_TYPE (rli
->prev_field
)
720 && ! integer_zerop (DECL_SIZE (rli
->prev_field
))))
722 unsigned int type_align
= TYPE_ALIGN (type
);
723 type_align
= MAX (type_align
, desired_align
);
724 if (maximum_field_alignment
!= 0)
725 type_align
= MIN (type_align
, maximum_field_alignment
);
726 rli
->record_align
= MAX (rli
->record_align
, type_align
);
727 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
730 #ifdef PCC_BITFIELD_TYPE_MATTERS
731 else if (is_bitfield
&& PCC_BITFIELD_TYPE_MATTERS
)
733 /* Named bit-fields cause the entire structure to have the
734 alignment implied by their type. */
735 if (DECL_NAME (field
) != 0)
737 unsigned int type_align
= TYPE_ALIGN (type
);
739 #ifdef ADJUST_FIELD_ALIGN
740 if (! TYPE_USER_ALIGN (type
))
741 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
744 if (maximum_field_alignment
!= 0)
745 type_align
= MIN (type_align
, maximum_field_alignment
);
746 else if (DECL_PACKED (field
))
747 type_align
= MIN (type_align
, BITS_PER_UNIT
);
749 /* The alignment of the record is increased to the maximum
750 of the current alignment, the alignment indicated on the
751 field (i.e., the alignment specified by an __aligned__
752 attribute), and the alignment indicated by the type of
754 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
755 rli
->record_align
= MAX (rli
->record_align
, type_align
);
758 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
759 user_align
|= TYPE_USER_ALIGN (type
);
765 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
766 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
769 TYPE_USER_ALIGN (rli
->t
) |= user_align
;
771 return desired_align
;
774 /* Called from place_field to handle unions. */
777 place_union_field (record_layout_info rli
, tree field
)
779 update_alignment_for_field (rli
, field
, /*known_align=*/0);
781 DECL_FIELD_OFFSET (field
) = size_zero_node
;
782 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
783 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
785 /* We assume the union's size will be a multiple of a byte so we don't
786 bother with BITPOS. */
787 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
788 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
789 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
790 rli
->offset
= fold (build (COND_EXPR
, sizetype
,
791 DECL_QUALIFIER (field
),
792 DECL_SIZE_UNIT (field
), rli
->offset
));
795 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
796 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
797 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
798 units of alignment than the underlying TYPE. */
800 excess_unit_span (HOST_WIDE_INT byte_offset
, HOST_WIDE_INT bit_offset
,
801 HOST_WIDE_INT size
, HOST_WIDE_INT align
, tree type
)
803 /* Note that the calculation of OFFSET might overflow; we calculate it so
804 that we still get the right result as long as ALIGN is a power of two. */
805 unsigned HOST_WIDE_INT offset
= byte_offset
* BITS_PER_UNIT
+ bit_offset
;
807 offset
= offset
% align
;
808 return ((offset
+ size
+ align
- 1) / align
809 > ((unsigned HOST_WIDE_INT
) tree_low_cst (TYPE_SIZE (type
), 1)
814 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
815 is a FIELD_DECL to be added after those fields already present in
816 T. (FIELD is not actually added to the TYPE_FIELDS list here;
817 callers that desire that behavior must manually perform that step.) */
820 place_field (record_layout_info rli
, tree field
)
822 /* The alignment required for FIELD. */
823 unsigned int desired_align
;
824 /* The alignment FIELD would have if we just dropped it into the
825 record as it presently stands. */
826 unsigned int known_align
;
827 unsigned int actual_align
;
828 /* The type of this field. */
829 tree type
= TREE_TYPE (field
);
831 if (TREE_CODE (field
) == ERROR_MARK
|| TREE_CODE (type
) == ERROR_MARK
)
834 /* If FIELD is static, then treat it like a separate variable, not
835 really like a structure field. If it is a FUNCTION_DECL, it's a
836 method. In both cases, all we do is lay out the decl, and we do
837 it *after* the record is laid out. */
838 if (TREE_CODE (field
) == VAR_DECL
)
840 rli
->pending_statics
= tree_cons (NULL_TREE
, field
,
841 rli
->pending_statics
);
845 /* Enumerators and enum types which are local to this class need not
846 be laid out. Likewise for initialized constant fields. */
847 else if (TREE_CODE (field
) != FIELD_DECL
)
850 /* Unions are laid out very differently than records, so split
851 that code off to another function. */
852 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
854 place_union_field (rli
, field
);
858 /* Work out the known alignment so far. Note that A & (-A) is the
859 value of the least-significant bit in A that is one. */
860 if (! integer_zerop (rli
->bitpos
))
861 known_align
= (tree_low_cst (rli
->bitpos
, 1)
862 & - tree_low_cst (rli
->bitpos
, 1));
863 else if (integer_zerop (rli
->offset
))
864 known_align
= BIGGEST_ALIGNMENT
;
865 else if (host_integerp (rli
->offset
, 1))
866 known_align
= (BITS_PER_UNIT
867 * (tree_low_cst (rli
->offset
, 1)
868 & - tree_low_cst (rli
->offset
, 1)));
870 known_align
= rli
->offset_align
;
872 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
874 if (warn_packed
&& DECL_PACKED (field
))
876 if (known_align
>= TYPE_ALIGN (type
))
878 if (TYPE_ALIGN (type
) > desired_align
)
880 if (STRICT_ALIGNMENT
)
881 warning ("%Jpacked attribute causes inefficient alignment "
882 "for '%D'", field
, field
);
884 warning ("%Jpacked attribute is unnecessary for '%D'",
889 rli
->packed_maybe_necessary
= 1;
892 /* Does this field automatically have alignment it needs by virtue
893 of the fields that precede it and the record's own alignment? */
894 if (known_align
< desired_align
)
896 /* No, we need to skip space before this field.
897 Bump the cumulative size to multiple of field alignment. */
900 warning ("%Jpadding struct to align '%D'", field
, field
);
902 /* If the alignment is still within offset_align, just align
904 if (desired_align
< rli
->offset_align
)
905 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
908 /* First adjust OFFSET by the partial bits, then align. */
910 = size_binop (PLUS_EXPR
, rli
->offset
,
912 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
913 bitsize_unit_node
)));
914 rli
->bitpos
= bitsize_zero_node
;
916 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
919 if (! TREE_CONSTANT (rli
->offset
))
920 rli
->offset_align
= desired_align
;
924 /* Handle compatibility with PCC. Note that if the record has any
925 variable-sized fields, we need not worry about compatibility. */
926 #ifdef PCC_BITFIELD_TYPE_MATTERS
927 if (PCC_BITFIELD_TYPE_MATTERS
928 && ! (* targetm
.ms_bitfield_layout_p
) (rli
->t
)
929 && TREE_CODE (field
) == FIELD_DECL
930 && type
!= error_mark_node
931 && DECL_BIT_FIELD (field
)
932 && ! DECL_PACKED (field
)
933 && maximum_field_alignment
== 0
934 && ! integer_zerop (DECL_SIZE (field
))
935 && host_integerp (DECL_SIZE (field
), 1)
936 && host_integerp (rli
->offset
, 1)
937 && host_integerp (TYPE_SIZE (type
), 1))
939 unsigned int type_align
= TYPE_ALIGN (type
);
940 tree dsize
= DECL_SIZE (field
);
941 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
942 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
943 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
945 #ifdef ADJUST_FIELD_ALIGN
946 if (! TYPE_USER_ALIGN (type
))
947 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
950 /* A bit field may not span more units of alignment of its type
951 than its type itself. Advance to next boundary if necessary. */
952 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
953 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
955 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
959 #ifdef BITFIELD_NBYTES_LIMITED
960 if (BITFIELD_NBYTES_LIMITED
961 && ! (* targetm
.ms_bitfield_layout_p
) (rli
->t
)
962 && TREE_CODE (field
) == FIELD_DECL
963 && type
!= error_mark_node
964 && DECL_BIT_FIELD_TYPE (field
)
965 && ! DECL_PACKED (field
)
966 && ! integer_zerop (DECL_SIZE (field
))
967 && host_integerp (DECL_SIZE (field
), 1)
968 && host_integerp (rli
->offset
, 1)
969 && host_integerp (TYPE_SIZE (type
), 1))
971 unsigned int type_align
= TYPE_ALIGN (type
);
972 tree dsize
= DECL_SIZE (field
);
973 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
974 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
975 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
977 #ifdef ADJUST_FIELD_ALIGN
978 if (! TYPE_USER_ALIGN (type
))
979 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
982 if (maximum_field_alignment
!= 0)
983 type_align
= MIN (type_align
, maximum_field_alignment
);
984 /* ??? This test is opposite the test in the containing if
985 statement, so this code is unreachable currently. */
986 else if (DECL_PACKED (field
))
987 type_align
= MIN (type_align
, BITS_PER_UNIT
);
989 /* A bit field may not span the unit of alignment of its type.
990 Advance to next boundary if necessary. */
991 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
992 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
994 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
998 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1000 When a bit field is inserted into a packed record, the whole
1001 size of the underlying type is used by one or more same-size
1002 adjacent bitfields. (That is, if its long:3, 32 bits is
1003 used in the record, and any additional adjacent long bitfields are
1004 packed into the same chunk of 32 bits. However, if the size
1005 changes, a new field of that size is allocated.) In an unpacked
1006 record, this is the same as using alignment, but not equivalent
1009 Note: for compatibility, we use the type size, not the type alignment
1010 to determine alignment, since that matches the documentation */
1012 if ((* targetm
.ms_bitfield_layout_p
) (rli
->t
)
1013 && ((DECL_BIT_FIELD_TYPE (field
) && ! DECL_PACKED (field
))
1014 || (rli
->prev_field
&& ! DECL_PACKED (rli
->prev_field
))))
1016 /* At this point, either the prior or current are bitfields,
1017 (possibly both), and we're dealing with MS packing. */
1018 tree prev_saved
= rli
->prev_field
;
1020 /* Is the prior field a bitfield? If so, handle "runs" of same
1021 type size fields. */
1022 if (rli
->prev_field
/* necessarily a bitfield if it exists. */)
1024 /* If both are bitfields, nonzero, and the same size, this is
1025 the middle of a run. Zero declared size fields are special
1026 and handled as "end of run". (Note: it's nonzero declared
1027 size, but equal type sizes!) (Since we know that both
1028 the current and previous fields are bitfields by the
1029 time we check it, DECL_SIZE must be present for both.) */
1030 if (DECL_BIT_FIELD_TYPE (field
)
1031 && !integer_zerop (DECL_SIZE (field
))
1032 && !integer_zerop (DECL_SIZE (rli
->prev_field
))
1033 && host_integerp (DECL_SIZE (rli
->prev_field
), 0)
1034 && host_integerp (TYPE_SIZE (type
), 0)
1035 && simple_cst_equal (TYPE_SIZE (type
),
1036 TYPE_SIZE (TREE_TYPE (rli
->prev_field
))))
1038 /* We're in the middle of a run of equal type size fields; make
1039 sure we realign if we run out of bits. (Not decl size,
1041 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 0);
1043 if (rli
->remaining_in_alignment
< bitsize
)
1045 /* out of bits; bump up to next 'word'. */
1046 rli
->offset
= DECL_FIELD_OFFSET (rli
->prev_field
);
1048 = size_binop (PLUS_EXPR
, TYPE_SIZE (type
),
1049 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1050 rli
->prev_field
= field
;
1051 rli
->remaining_in_alignment
1052 = tree_low_cst (TYPE_SIZE (type
), 0);
1055 rli
->remaining_in_alignment
-= bitsize
;
1059 /* End of a run: if leaving a run of bitfields of the same type
1060 size, we have to "use up" the rest of the bits of the type
1063 Compute the new position as the sum of the size for the prior
1064 type and where we first started working on that type.
1065 Note: since the beginning of the field was aligned then
1066 of course the end will be too. No round needed. */
1068 if (!integer_zerop (DECL_SIZE (rli
->prev_field
)))
1070 tree type_size
= TYPE_SIZE (TREE_TYPE (rli
->prev_field
));
1073 = size_binop (PLUS_EXPR
, type_size
,
1074 DECL_FIELD_BIT_OFFSET (rli
->prev_field
));
1077 /* We "use up" size zero fields; the code below should behave
1078 as if the prior field was not a bitfield. */
1081 /* Cause a new bitfield to be captured, either this time (if
1082 currently a bitfield) or next time we see one. */
1083 if (!DECL_BIT_FIELD_TYPE(field
)
1084 || integer_zerop (DECL_SIZE (field
)))
1085 rli
->prev_field
= NULL
;
1088 rli
->offset_align
= tree_low_cst (TYPE_SIZE (type
), 0);
1089 normalize_rli (rli
);
1092 /* If we're starting a new run of same size type bitfields
1093 (or a run of non-bitfields), set up the "first of the run"
1096 That is, if the current field is not a bitfield, or if there
1097 was a prior bitfield the type sizes differ, or if there wasn't
1098 a prior bitfield the size of the current field is nonzero.
1100 Note: we must be sure to test ONLY the type size if there was
1101 a prior bitfield and ONLY for the current field being zero if
1104 if (!DECL_BIT_FIELD_TYPE (field
)
1105 || ( prev_saved
!= NULL
1106 ? !simple_cst_equal (TYPE_SIZE (type
),
1107 TYPE_SIZE (TREE_TYPE (prev_saved
)))
1108 : !integer_zerop (DECL_SIZE (field
)) ))
1110 /* Never smaller than a byte for compatibility. */
1111 unsigned int type_align
= BITS_PER_UNIT
;
1113 /* (When not a bitfield), we could be seeing a flex array (with
1114 no DECL_SIZE). Since we won't be using remaining_in_alignment
1115 until we see a bitfield (and come by here again) we just skip
1117 if (DECL_SIZE (field
) != NULL
1118 && host_integerp (TYPE_SIZE (TREE_TYPE (field
)), 0)
1119 && host_integerp (DECL_SIZE (field
), 0))
1120 rli
->remaining_in_alignment
1121 = tree_low_cst (TYPE_SIZE (TREE_TYPE(field
)), 0)
1122 - tree_low_cst (DECL_SIZE (field
), 0);
1124 /* Now align (conventionally) for the new type. */
1125 if (!DECL_PACKED(field
))
1126 type_align
= MAX(TYPE_ALIGN (type
), type_align
);
1129 && DECL_BIT_FIELD_TYPE (prev_saved
)
1130 /* If the previous bit-field is zero-sized, we've already
1131 accounted for its alignment needs (or ignored it, if
1132 appropriate) while placing it. */
1133 && ! integer_zerop (DECL_SIZE (prev_saved
)))
1134 type_align
= MAX (type_align
,
1135 TYPE_ALIGN (TREE_TYPE (prev_saved
)));
1137 if (maximum_field_alignment
!= 0)
1138 type_align
= MIN (type_align
, maximum_field_alignment
);
1140 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1142 /* If we really aligned, don't allow subsequent bitfields
1144 rli
->prev_field
= NULL
;
1148 /* Offset so far becomes the position of this field after normalizing. */
1149 normalize_rli (rli
);
1150 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1151 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1152 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1154 /* If this field ended up more aligned than we thought it would be (we
1155 approximate this by seeing if its position changed), lay out the field
1156 again; perhaps we can use an integral mode for it now. */
1157 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
1158 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
1159 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
1160 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
1161 actual_align
= BIGGEST_ALIGNMENT
;
1162 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
1163 actual_align
= (BITS_PER_UNIT
1164 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
1165 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
1167 actual_align
= DECL_OFFSET_ALIGN (field
);
1169 if (known_align
!= actual_align
)
1170 layout_decl (field
, actual_align
);
1172 /* Only the MS bitfields use this. */
1173 if (rli
->prev_field
== NULL
&& DECL_BIT_FIELD_TYPE(field
))
1174 rli
->prev_field
= field
;
1176 /* Now add size of this field to the size of the record. If the size is
1177 not constant, treat the field as being a multiple of bytes and just
1178 adjust the offset, resetting the bit position. Otherwise, apportion the
1179 size amongst the bit position and offset. First handle the case of an
1180 unspecified size, which can happen when we have an invalid nested struct
1181 definition, such as struct j { struct j { int i; } }. The error message
1182 is printed in finish_struct. */
1183 if (DECL_SIZE (field
) == 0)
1185 else if (TREE_CODE (DECL_SIZE_UNIT (field
)) != INTEGER_CST
1186 || TREE_CONSTANT_OVERFLOW (DECL_SIZE_UNIT (field
)))
1189 = size_binop (PLUS_EXPR
, rli
->offset
,
1191 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1192 bitsize_unit_node
)));
1194 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1195 rli
->bitpos
= bitsize_zero_node
;
1196 rli
->offset_align
= MIN (rli
->offset_align
, desired_align
);
1200 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1201 normalize_rli (rli
);
1205 /* Assuming that all the fields have been laid out, this function uses
1206 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1207 indicated by RLI. */
1210 finalize_record_size (record_layout_info rli
)
1212 tree unpadded_size
, unpadded_size_unit
;
1214 /* Now we want just byte and bit offsets, so set the offset alignment
1215 to be a byte and then normalize. */
1216 rli
->offset_align
= BITS_PER_UNIT
;
1217 normalize_rli (rli
);
1219 /* Determine the desired alignment. */
1220 #ifdef ROUND_TYPE_ALIGN
1221 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
1224 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
1227 /* Compute the size so far. Be sure to allow for extra bits in the
1228 size in bytes. We have guaranteed above that it will be no more
1229 than a single byte. */
1230 unpadded_size
= rli_size_so_far (rli
);
1231 unpadded_size_unit
= rli_size_unit_so_far (rli
);
1232 if (! integer_zerop (rli
->bitpos
))
1234 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
1236 /* Round the size up to be a multiple of the required alignment. */
1237 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
1238 TYPE_SIZE_UNIT (rli
->t
) = round_up (unpadded_size_unit
,
1239 TYPE_ALIGN (rli
->t
) / BITS_PER_UNIT
);
1241 if (warn_padded
&& TREE_CONSTANT (unpadded_size
)
1242 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0)
1243 warning ("padding struct size to alignment boundary");
1245 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
1246 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
1247 && TREE_CONSTANT (unpadded_size
))
1251 #ifdef ROUND_TYPE_ALIGN
1253 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1255 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1258 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
1259 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
1261 TYPE_PACKED (rli
->t
) = 0;
1263 if (TYPE_NAME (rli
->t
))
1267 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1268 name
= IDENTIFIER_POINTER (TYPE_NAME (rli
->t
));
1270 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (rli
->t
)));
1272 if (STRICT_ALIGNMENT
)
1273 warning ("packed attribute causes inefficient alignment for `%s'", name
);
1275 warning ("packed attribute is unnecessary for `%s'", name
);
1279 if (STRICT_ALIGNMENT
)
1280 warning ("packed attribute causes inefficient alignment");
1282 warning ("packed attribute is unnecessary");
1288 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1291 compute_record_mode (tree type
)
1294 enum machine_mode mode
= VOIDmode
;
1296 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1297 However, if possible, we use a mode that fits in a register
1298 instead, in order to allow for better optimization down the
1300 TYPE_MODE (type
) = BLKmode
;
1302 if (! host_integerp (TYPE_SIZE (type
), 1))
1305 /* A record which has any BLKmode members must itself be
1306 BLKmode; it can't go in a register. Unless the member is
1307 BLKmode only because it isn't aligned. */
1308 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1310 if (TREE_CODE (field
) != FIELD_DECL
)
1313 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1314 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1315 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
))
1316 && !(TYPE_SIZE (TREE_TYPE (field
)) != 0
1317 && integer_zerop (TYPE_SIZE (TREE_TYPE (field
)))))
1318 || ! host_integerp (bit_position (field
), 1)
1319 || DECL_SIZE (field
) == 0
1320 || ! host_integerp (DECL_SIZE (field
), 1))
1323 /* If this field is the whole struct, remember its mode so
1324 that, say, we can put a double in a class into a DF
1325 register instead of forcing it to live in the stack. */
1326 if (simple_cst_equal (TYPE_SIZE (type
), DECL_SIZE (field
)))
1327 mode
= DECL_MODE (field
);
1329 #ifdef MEMBER_TYPE_FORCES_BLK
1330 /* With some targets, eg. c4x, it is sub-optimal
1331 to access an aligned BLKmode structure as a scalar. */
1333 if (MEMBER_TYPE_FORCES_BLK (field
, mode
))
1335 #endif /* MEMBER_TYPE_FORCES_BLK */
1338 /* If we only have one real field; use its mode. This only applies to
1339 RECORD_TYPE. This does not apply to unions. */
1340 if (TREE_CODE (type
) == RECORD_TYPE
&& mode
!= VOIDmode
)
1341 TYPE_MODE (type
) = mode
;
1343 TYPE_MODE (type
) = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1345 /* If structure's known alignment is less than what the scalar
1346 mode would need, and it matters, then stick with BLKmode. */
1347 if (TYPE_MODE (type
) != BLKmode
1349 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1350 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1352 /* If this is the only reason this type is BLKmode, then
1353 don't force containing types to be BLKmode. */
1354 TYPE_NO_FORCE_BLK (type
) = 1;
1355 TYPE_MODE (type
) = BLKmode
;
1359 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1363 finalize_type_size (tree type
)
1365 /* Normally, use the alignment corresponding to the mode chosen.
1366 However, where strict alignment is not required, avoid
1367 over-aligning structures, since most compilers do not do this
1370 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1371 && (STRICT_ALIGNMENT
1372 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1373 && TREE_CODE (type
) != QUAL_UNION_TYPE
1374 && TREE_CODE (type
) != ARRAY_TYPE
)))
1376 TYPE_ALIGN (type
) = GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1377 TYPE_USER_ALIGN (type
) = 0;
1380 /* Do machine-dependent extra alignment. */
1381 #ifdef ROUND_TYPE_ALIGN
1383 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1386 /* If we failed to find a simple way to calculate the unit size
1387 of the type, find it by division. */
1388 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1389 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1390 result will fit in sizetype. We will get more efficient code using
1391 sizetype, so we force a conversion. */
1392 TYPE_SIZE_UNIT (type
)
1393 = convert (sizetype
,
1394 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1395 bitsize_unit_node
));
1397 if (TYPE_SIZE (type
) != 0)
1399 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1400 TYPE_SIZE_UNIT (type
)
1401 = round_up (TYPE_SIZE_UNIT (type
), TYPE_ALIGN (type
) / BITS_PER_UNIT
);
1404 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1405 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1406 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1407 if (TYPE_SIZE_UNIT (type
) != 0
1408 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1409 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1411 /* Also layout any other variants of the type. */
1412 if (TYPE_NEXT_VARIANT (type
)
1413 || type
!= TYPE_MAIN_VARIANT (type
))
1416 /* Record layout info of this variant. */
1417 tree size
= TYPE_SIZE (type
);
1418 tree size_unit
= TYPE_SIZE_UNIT (type
);
1419 unsigned int align
= TYPE_ALIGN (type
);
1420 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1421 enum machine_mode mode
= TYPE_MODE (type
);
1423 /* Copy it into all variants. */
1424 for (variant
= TYPE_MAIN_VARIANT (type
);
1426 variant
= TYPE_NEXT_VARIANT (variant
))
1428 TYPE_SIZE (variant
) = size
;
1429 TYPE_SIZE_UNIT (variant
) = size_unit
;
1430 TYPE_ALIGN (variant
) = align
;
1431 TYPE_USER_ALIGN (variant
) = user_align
;
1432 TYPE_MODE (variant
) = mode
;
1437 /* Do all of the work required to layout the type indicated by RLI,
1438 once the fields have been laid out. This function will call `free'
1439 for RLI, unless FREE_P is false. Passing a value other than false
1440 for FREE_P is bad practice; this option only exists to support the
1444 finish_record_layout (record_layout_info rli
, int free_p
)
1446 /* Compute the final size. */
1447 finalize_record_size (rli
);
1449 /* Compute the TYPE_MODE for the record. */
1450 compute_record_mode (rli
->t
);
1452 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1453 finalize_type_size (rli
->t
);
1455 /* Lay out any static members. This is done now because their type
1456 may use the record's type. */
1457 while (rli
->pending_statics
)
1459 layout_decl (TREE_VALUE (rli
->pending_statics
), 0);
1460 rli
->pending_statics
= TREE_CHAIN (rli
->pending_statics
);
1469 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1470 NAME, its fields are chained in reverse on FIELDS.
1472 If ALIGN_TYPE is non-null, it is given the same alignment as
1476 finish_builtin_struct (tree type
, const char *name
, tree fields
,
1481 for (tail
= NULL_TREE
; fields
; tail
= fields
, fields
= next
)
1483 DECL_FIELD_CONTEXT (fields
) = type
;
1484 next
= TREE_CHAIN (fields
);
1485 TREE_CHAIN (fields
) = tail
;
1487 TYPE_FIELDS (type
) = tail
;
1491 TYPE_ALIGN (type
) = TYPE_ALIGN (align_type
);
1492 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (align_type
);
1496 #if 0 /* not yet, should get fixed properly later */
1497 TYPE_NAME (type
) = make_type_decl (get_identifier (name
), type
);
1499 TYPE_NAME (type
) = build_decl (TYPE_DECL
, get_identifier (name
), type
);
1501 TYPE_STUB_DECL (type
) = TYPE_NAME (type
);
1502 layout_decl (TYPE_NAME (type
), 0);
1505 /* Calculate the mode, size, and alignment for TYPE.
1506 For an array type, calculate the element separation as well.
1507 Record TYPE on the chain of permanent or temporary types
1508 so that dbxout will find out about it.
1510 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1511 layout_type does nothing on such a type.
1513 If the type is incomplete, its TYPE_SIZE remains zero. */
1516 layout_type (tree type
)
1521 /* Do nothing if type has been laid out before. */
1522 if (TYPE_SIZE (type
))
1525 switch (TREE_CODE (type
))
1528 /* This kind of type is the responsibility
1529 of the language-specific code. */
1532 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1533 if (TYPE_PRECISION (type
) == 0)
1534 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1536 /* ... fall through ... */
1541 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1542 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1543 TREE_UNSIGNED (type
) = 1;
1545 TYPE_MODE (type
) = smallest_mode_for_size (TYPE_PRECISION (type
),
1547 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1548 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1552 TYPE_MODE (type
) = mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0);
1553 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1554 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1558 TREE_UNSIGNED (type
) = TREE_UNSIGNED (TREE_TYPE (type
));
1560 = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1561 (TREE_CODE (TREE_TYPE (type
)) == INTEGER_TYPE
1562 ? MODE_COMPLEX_INT
: MODE_COMPLEX_FLOAT
),
1564 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1565 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1572 subtype
= TREE_TYPE (type
);
1573 TREE_UNSIGNED (type
) = TREE_UNSIGNED (subtype
);
1574 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1575 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1580 /* This is an incomplete type and so doesn't have a size. */
1581 TYPE_ALIGN (type
) = 1;
1582 TYPE_USER_ALIGN (type
) = 0;
1583 TYPE_MODE (type
) = VOIDmode
;
1587 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1588 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1589 /* A pointer might be MODE_PARTIAL_INT,
1590 but ptrdiff_t must be integral. */
1591 TYPE_MODE (type
) = mode_for_size (POINTER_SIZE
, MODE_INT
, 0);
1596 TYPE_MODE (type
) = mode_for_size (2 * POINTER_SIZE
, MODE_INT
, 0);
1597 TYPE_SIZE (type
) = bitsize_int (2 * POINTER_SIZE
);
1598 TYPE_SIZE_UNIT (type
) = size_int ((2 * POINTER_SIZE
) / BITS_PER_UNIT
);
1602 case REFERENCE_TYPE
:
1605 enum machine_mode mode
= ((TREE_CODE (type
) == REFERENCE_TYPE
1606 && reference_types_internal
)
1607 ? Pmode
: TYPE_MODE (type
));
1609 int nbits
= GET_MODE_BITSIZE (mode
);
1611 TYPE_SIZE (type
) = bitsize_int (nbits
);
1612 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (mode
));
1613 TREE_UNSIGNED (type
) = 1;
1614 TYPE_PRECISION (type
) = nbits
;
1620 tree index
= TYPE_DOMAIN (type
);
1621 tree element
= TREE_TYPE (type
);
1623 build_pointer_type (element
);
1625 /* We need to know both bounds in order to compute the size. */
1626 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1627 && TYPE_SIZE (element
))
1629 tree ub
= TYPE_MAX_VALUE (index
);
1630 tree lb
= TYPE_MIN_VALUE (index
);
1634 /* The initial subtraction should happen in the original type so
1635 that (possible) negative values are handled appropriately. */
1636 length
= size_binop (PLUS_EXPR
, size_one_node
,
1638 fold (build (MINUS_EXPR
,
1642 /* Special handling for arrays of bits (for Chill). */
1643 element_size
= TYPE_SIZE (element
);
1644 if (TYPE_PACKED (type
) && INTEGRAL_TYPE_P (element
)
1645 && (integer_zerop (TYPE_MAX_VALUE (element
))
1646 || integer_onep (TYPE_MAX_VALUE (element
)))
1647 && host_integerp (TYPE_MIN_VALUE (element
), 1))
1649 HOST_WIDE_INT maxvalue
1650 = tree_low_cst (TYPE_MAX_VALUE (element
), 1);
1651 HOST_WIDE_INT minvalue
1652 = tree_low_cst (TYPE_MIN_VALUE (element
), 1);
1654 if (maxvalue
- minvalue
== 1
1655 && (maxvalue
== 1 || maxvalue
== 0))
1656 element_size
= integer_one_node
;
1659 /* If neither bound is a constant and sizetype is signed, make
1660 sure the size is never negative. We should really do this
1661 if *either* bound is non-constant, but this is the best
1662 compromise between C and Ada. */
1663 if (! TREE_UNSIGNED (sizetype
)
1664 && TREE_CODE (TYPE_MIN_VALUE (index
)) != INTEGER_CST
1665 && TREE_CODE (TYPE_MAX_VALUE (index
)) != INTEGER_CST
)
1666 length
= size_binop (MAX_EXPR
, length
, size_zero_node
);
1668 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1669 convert (bitsizetype
, length
));
1671 /* If we know the size of the element, calculate the total
1672 size directly, rather than do some division thing below.
1673 This optimization helps Fortran assumed-size arrays
1674 (where the size of the array is determined at runtime)
1676 Note that we can't do this in the case where the size of
1677 the elements is one bit since TYPE_SIZE_UNIT cannot be
1678 set correctly in that case. */
1679 if (TYPE_SIZE_UNIT (element
) != 0 && ! integer_onep (element_size
))
1680 TYPE_SIZE_UNIT (type
)
1681 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1684 /* Now round the alignment and size,
1685 using machine-dependent criteria if any. */
1687 #ifdef ROUND_TYPE_ALIGN
1689 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1691 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1693 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (element
);
1694 TYPE_MODE (type
) = BLKmode
;
1695 if (TYPE_SIZE (type
) != 0
1696 #ifdef MEMBER_TYPE_FORCES_BLK
1697 && ! MEMBER_TYPE_FORCES_BLK (type
, VOIDmode
)
1699 /* BLKmode elements force BLKmode aggregate;
1700 else extract/store fields may lose. */
1701 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
1702 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
1704 /* One-element arrays get the component type's mode. */
1705 if (simple_cst_equal (TYPE_SIZE (type
),
1706 TYPE_SIZE (TREE_TYPE (type
))))
1707 TYPE_MODE (type
) = TYPE_MODE (TREE_TYPE (type
));
1710 = mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1);
1712 if (TYPE_MODE (type
) != BLKmode
1713 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
1714 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
))
1715 && TYPE_MODE (type
) != BLKmode
)
1717 TYPE_NO_FORCE_BLK (type
) = 1;
1718 TYPE_MODE (type
) = BLKmode
;
1726 case QUAL_UNION_TYPE
:
1729 record_layout_info rli
;
1731 /* Initialize the layout information. */
1732 rli
= start_record_layout (type
);
1734 /* If this is a QUAL_UNION_TYPE, we want to process the fields
1735 in the reverse order in building the COND_EXPR that denotes
1736 its size. We reverse them again later. */
1737 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1738 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1740 /* Place all the fields. */
1741 for (field
= TYPE_FIELDS (type
); field
; field
= TREE_CHAIN (field
))
1742 place_field (rli
, field
);
1744 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
1745 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
1747 if (lang_adjust_rli
)
1748 (*lang_adjust_rli
) (rli
);
1750 /* Finish laying out the record. */
1751 finish_record_layout (rli
, /*free_p=*/true);
1755 case SET_TYPE
: /* Used by Chill and Pascal. */
1756 if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
1757 || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type
))) != INTEGER_CST
)
1761 #ifndef SET_WORD_SIZE
1762 #define SET_WORD_SIZE BITS_PER_WORD
1764 unsigned int alignment
1765 = set_alignment
? set_alignment
: SET_WORD_SIZE
;
1766 HOST_WIDE_INT size_in_bits
1767 = (tree_low_cst (TYPE_MAX_VALUE (TYPE_DOMAIN (type
)), 0)
1768 - tree_low_cst (TYPE_MIN_VALUE (TYPE_DOMAIN (type
)), 0) + 1);
1769 HOST_WIDE_INT rounded_size
1770 = ((size_in_bits
+ alignment
- 1) / alignment
) * alignment
;
1772 if (rounded_size
> (int) alignment
)
1773 TYPE_MODE (type
) = BLKmode
;
1775 TYPE_MODE (type
) = mode_for_size (alignment
, MODE_INT
, 1);
1777 TYPE_SIZE (type
) = bitsize_int (rounded_size
);
1778 TYPE_SIZE_UNIT (type
) = size_int (rounded_size
/ BITS_PER_UNIT
);
1779 TYPE_ALIGN (type
) = alignment
;
1780 TYPE_USER_ALIGN (type
) = 0;
1781 TYPE_PRECISION (type
) = size_in_bits
;
1786 /* The size may vary in different languages, so the language front end
1787 should fill in the size. */
1788 TYPE_ALIGN (type
) = BIGGEST_ALIGNMENT
;
1789 TYPE_USER_ALIGN (type
) = 0;
1790 TYPE_MODE (type
) = BLKmode
;
1797 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
1798 records and unions, finish_record_layout already called this
1800 if (TREE_CODE (type
) != RECORD_TYPE
1801 && TREE_CODE (type
) != UNION_TYPE
1802 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
1803 finalize_type_size (type
);
1805 /* If this type is created before sizetype has been permanently set,
1806 record it so set_sizetype can fix it up. */
1808 early_type_list
= tree_cons (NULL_TREE
, type
, early_type_list
);
1810 /* If an alias set has been set for this aggregate when it was incomplete,
1811 force it into alias set 0.
1812 This is too conservative, but we cannot call record_component_aliases
1813 here because some frontends still change the aggregates after
1815 if (AGGREGATE_TYPE_P (type
) && TYPE_ALIAS_SET_KNOWN_P (type
))
1816 TYPE_ALIAS_SET (type
) = 0;
1819 /* Create and return a type for signed integers of PRECISION bits. */
1822 make_signed_type (int precision
)
1824 tree type
= make_node (INTEGER_TYPE
);
1826 TYPE_PRECISION (type
) = precision
;
1828 fixup_signed_type (type
);
1832 /* Create and return a type for unsigned integers of PRECISION bits. */
1835 make_unsigned_type (int precision
)
1837 tree type
= make_node (INTEGER_TYPE
);
1839 TYPE_PRECISION (type
) = precision
;
1841 fixup_unsigned_type (type
);
1845 /* Initialize sizetype and bitsizetype to a reasonable and temporary
1846 value to enable integer types to be created. */
1849 initialize_sizetypes (void)
1851 tree t
= make_node (INTEGER_TYPE
);
1853 /* Set this so we do something reasonable for the build_int_2 calls
1855 integer_type_node
= t
;
1857 TYPE_MODE (t
) = SImode
;
1858 TYPE_ALIGN (t
) = GET_MODE_ALIGNMENT (SImode
);
1859 TYPE_USER_ALIGN (t
) = 0;
1860 TYPE_SIZE (t
) = build_int_2 (GET_MODE_BITSIZE (SImode
), 0);
1861 TYPE_SIZE_UNIT (t
) = build_int_2 (GET_MODE_SIZE (SImode
), 0);
1862 TREE_UNSIGNED (t
) = 1;
1863 TYPE_PRECISION (t
) = GET_MODE_BITSIZE (SImode
);
1864 TYPE_MIN_VALUE (t
) = build_int_2 (0, 0);
1865 TYPE_IS_SIZETYPE (t
) = 1;
1867 /* 1000 avoids problems with possible overflow and is certainly
1868 larger than any size value we'd want to be storing. */
1869 TYPE_MAX_VALUE (t
) = build_int_2 (1000, 0);
1871 /* These two must be different nodes because of the caching done in
1874 bitsizetype
= copy_node (t
);
1875 integer_type_node
= 0;
1878 /* Set sizetype to TYPE, and initialize *sizetype accordingly.
1879 Also update the type of any standard type's sizes made so far. */
1882 set_sizetype (tree type
)
1884 int oprecision
= TYPE_PRECISION (type
);
1885 /* The *bitsizetype types use a precision that avoids overflows when
1886 calculating signed sizes / offsets in bits. However, when
1887 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
1889 int precision
= MIN (oprecision
+ BITS_PER_UNIT_LOG
+ 1,
1890 2 * HOST_BITS_PER_WIDE_INT
);
1897 /* Make copies of nodes since we'll be setting TYPE_IS_SIZETYPE. */
1898 sizetype
= copy_node (type
);
1899 TYPE_DOMAIN (sizetype
) = type
;
1900 TYPE_IS_SIZETYPE (sizetype
) = 1;
1901 bitsizetype
= make_node (INTEGER_TYPE
);
1902 TYPE_NAME (bitsizetype
) = TYPE_NAME (type
);
1903 TYPE_PRECISION (bitsizetype
) = precision
;
1904 TYPE_IS_SIZETYPE (bitsizetype
) = 1;
1906 if (TREE_UNSIGNED (type
))
1907 fixup_unsigned_type (bitsizetype
);
1909 fixup_signed_type (bitsizetype
);
1911 layout_type (bitsizetype
);
1913 if (TREE_UNSIGNED (type
))
1915 usizetype
= sizetype
;
1916 ubitsizetype
= bitsizetype
;
1917 ssizetype
= copy_node (make_signed_type (oprecision
));
1918 sbitsizetype
= copy_node (make_signed_type (precision
));
1922 ssizetype
= sizetype
;
1923 sbitsizetype
= bitsizetype
;
1924 usizetype
= copy_node (make_unsigned_type (oprecision
));
1925 ubitsizetype
= copy_node (make_unsigned_type (precision
));
1928 TYPE_NAME (bitsizetype
) = get_identifier ("bit_size_type");
1930 /* Show is a sizetype, is a main type, and has no pointers to it. */
1931 for (i
= 0; i
< ARRAY_SIZE (sizetype_tab
); i
++)
1933 TYPE_IS_SIZETYPE (sizetype_tab
[i
]) = 1;
1934 TYPE_MAIN_VARIANT (sizetype_tab
[i
]) = sizetype_tab
[i
];
1935 TYPE_NEXT_VARIANT (sizetype_tab
[i
]) = 0;
1936 TYPE_POINTER_TO (sizetype_tab
[i
]) = 0;
1937 TYPE_REFERENCE_TO (sizetype_tab
[i
]) = 0;
1940 /* Go down each of the types we already made and set the proper type
1941 for the sizes in them. */
1942 for (t
= early_type_list
; t
!= 0; t
= TREE_CHAIN (t
))
1944 if (TREE_CODE (TREE_VALUE (t
)) != INTEGER_TYPE
1945 && TREE_CODE (TREE_VALUE (t
)) != BOOLEAN_TYPE
)
1948 TREE_TYPE (TYPE_SIZE (TREE_VALUE (t
))) = bitsizetype
;
1949 TREE_TYPE (TYPE_SIZE_UNIT (TREE_VALUE (t
))) = sizetype
;
1952 early_type_list
= 0;
1956 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE,
1957 BOOLEAN_TYPE, or CHAR_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
1958 for TYPE, based on the PRECISION and whether or not the TYPE
1959 IS_UNSIGNED. PRECISION need not correspond to a width supported
1960 natively by the hardware; for example, on a machine with 8-bit,
1961 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
1965 set_min_and_max_values_for_integral_type (tree type
,
1974 min_value
= build_int_2 (0, 0);
1976 = build_int_2 (precision
- HOST_BITS_PER_WIDE_INT
>= 0
1977 ? -1 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
1978 precision
- HOST_BITS_PER_WIDE_INT
> 0
1979 ? ((unsigned HOST_WIDE_INT
) ~0
1980 >> (HOST_BITS_PER_WIDE_INT
1981 - (precision
- HOST_BITS_PER_WIDE_INT
)))
1987 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1988 ? 0 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
1989 (((HOST_WIDE_INT
) (-1)
1990 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1991 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
1994 = build_int_2 ((precision
- HOST_BITS_PER_WIDE_INT
> 0
1995 ? -1 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
1996 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
1997 ? (((HOST_WIDE_INT
) 1
1998 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
2002 TREE_TYPE (min_value
) = type
;
2003 TREE_TYPE (max_value
) = type
;
2004 TYPE_MIN_VALUE (type
) = min_value
;
2005 TYPE_MAX_VALUE (type
) = max_value
;
2008 /* Set the extreme values of TYPE based on its precision in bits,
2009 then lay it out. Used when make_signed_type won't do
2010 because the tree code is not INTEGER_TYPE.
2011 E.g. for Pascal, when the -fsigned-char option is given. */
2014 fixup_signed_type (tree type
)
2016 int precision
= TYPE_PRECISION (type
);
2018 /* We can not represent properly constants greater then
2019 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2020 as they are used by i386 vector extensions and friends. */
2021 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2022 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2024 set_min_and_max_values_for_integral_type (type
, precision
,
2025 /*is_unsigned=*/false);
2027 /* Lay out the type: set its alignment, size, etc. */
2031 /* Set the extreme values of TYPE based on its precision in bits,
2032 then lay it out. This is used both in `make_unsigned_type'
2033 and for enumeral types. */
2036 fixup_unsigned_type (tree type
)
2038 int precision
= TYPE_PRECISION (type
);
2040 /* We can not represent properly constants greater then
2041 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2042 as they are used by i386 vector extensions and friends. */
2043 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2044 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2046 set_min_and_max_values_for_integral_type (type
, precision
,
2047 /*is_unsigned=*/true);
2049 /* Lay out the type: set its alignment, size, etc. */
2053 /* Find the best machine mode to use when referencing a bit field of length
2054 BITSIZE bits starting at BITPOS.
2056 The underlying object is known to be aligned to a boundary of ALIGN bits.
2057 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2058 larger than LARGEST_MODE (usually SImode).
2060 If no mode meets all these conditions, we return VOIDmode. Otherwise, if
2061 VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
2062 mode meeting these conditions.
2064 Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
2065 the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2066 all the conditions. */
2069 get_best_mode (int bitsize
, int bitpos
, unsigned int align
,
2070 enum machine_mode largest_mode
, int volatilep
)
2072 enum machine_mode mode
;
2073 unsigned int unit
= 0;
2075 /* Find the narrowest integer mode that contains the bit field. */
2076 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
2077 mode
= GET_MODE_WIDER_MODE (mode
))
2079 unit
= GET_MODE_BITSIZE (mode
);
2080 if ((bitpos
% unit
) + bitsize
<= unit
)
2084 if (mode
== VOIDmode
2085 /* It is tempting to omit the following line
2086 if STRICT_ALIGNMENT is true.
2087 But that is incorrect, since if the bitfield uses part of 3 bytes
2088 and we use a 4-byte mode, we could get a spurious segv
2089 if the extra 4th byte is past the end of memory.
2090 (Though at least one Unix compiler ignores this problem:
2091 that on the Sequent 386 machine. */
2092 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
2093 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
2096 if (SLOW_BYTE_ACCESS
&& ! volatilep
)
2098 enum machine_mode wide_mode
= VOIDmode
, tmode
;
2100 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
2101 tmode
= GET_MODE_WIDER_MODE (tmode
))
2103 unit
= GET_MODE_BITSIZE (tmode
);
2104 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
2105 && unit
<= BITS_PER_WORD
2106 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
2107 && (largest_mode
== VOIDmode
2108 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
2112 if (wide_mode
!= VOIDmode
)
2119 #include "gt-stor-layout.h"