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, 2007, 2008, 2009, 2010
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 3, 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 COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
25 #include "coretypes.h"
34 #include "diagnostic-core.h"
37 #include "langhooks.h"
41 #include "tree-inline.h"
42 #include "tree-dump.h"
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
= TARGET_DEFAULT_PACK_STRUCT
* BITS_PER_UNIT
;
53 /* Nonzero if all REFERENCE_TYPEs are internal and hence should be allocated
54 in the address spaces' address_mode, not pointer_mode. Set only by
55 internal_reference_types called only by a front end. */
56 static int reference_types_internal
= 0;
58 static tree
self_referential_size (tree
);
59 static void finalize_record_size (record_layout_info
);
60 static void finalize_type_size (tree
);
61 static void place_union_field (record_layout_info
, tree
);
62 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
63 static int excess_unit_span (HOST_WIDE_INT
, HOST_WIDE_INT
, HOST_WIDE_INT
,
66 extern void debug_rli (record_layout_info
);
68 /* Show that REFERENCE_TYPES are internal and should use address_mode.
69 Called only by front end. */
72 internal_reference_types (void)
74 reference_types_internal
= 1;
77 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
78 to serve as the actual size-expression for a type or decl. */
81 variable_size (tree size
)
84 if (TREE_CONSTANT (size
))
87 /* If the size is self-referential, we can't make a SAVE_EXPR (see
88 save_expr for the rationale). But we can do something else. */
89 if (CONTAINS_PLACEHOLDER_P (size
))
90 return self_referential_size (size
);
92 /* If we are in the global binding level, we can't make a SAVE_EXPR
93 since it may end up being shared across functions, so it is up
94 to the front-end to deal with this case. */
95 if (lang_hooks
.decls
.global_bindings_p ())
98 return save_expr (size
);
101 /* An array of functions used for self-referential size computation. */
102 static GTY(()) VEC (tree
, gc
) *size_functions
;
104 /* Look inside EXPR into simple arithmetic operations involving constants.
105 Return the outermost non-arithmetic or non-constant node. */
108 skip_simple_constant_arithmetic (tree expr
)
112 if (UNARY_CLASS_P (expr
))
113 expr
= TREE_OPERAND (expr
, 0);
114 else if (BINARY_CLASS_P (expr
))
116 if (TREE_CONSTANT (TREE_OPERAND (expr
, 1)))
117 expr
= TREE_OPERAND (expr
, 0);
118 else if (TREE_CONSTANT (TREE_OPERAND (expr
, 0)))
119 expr
= TREE_OPERAND (expr
, 1);
130 /* Similar to copy_tree_r but do not copy component references involving
131 PLACEHOLDER_EXPRs. These nodes are spotted in find_placeholder_in_expr
132 and substituted in substitute_in_expr. */
135 copy_self_referential_tree_r (tree
*tp
, int *walk_subtrees
, void *data
)
137 enum tree_code code
= TREE_CODE (*tp
);
139 /* Stop at types, decls, constants like copy_tree_r. */
140 if (TREE_CODE_CLASS (code
) == tcc_type
141 || TREE_CODE_CLASS (code
) == tcc_declaration
142 || TREE_CODE_CLASS (code
) == tcc_constant
)
148 /* This is the pattern built in ada/make_aligning_type. */
149 else if (code
== ADDR_EXPR
150 && TREE_CODE (TREE_OPERAND (*tp
, 0)) == PLACEHOLDER_EXPR
)
156 /* Default case: the component reference. */
157 else if (code
== COMPONENT_REF
)
160 for (inner
= TREE_OPERAND (*tp
, 0);
161 REFERENCE_CLASS_P (inner
);
162 inner
= TREE_OPERAND (inner
, 0))
165 if (TREE_CODE (inner
) == PLACEHOLDER_EXPR
)
172 /* We're not supposed to have them in self-referential size trees
173 because we wouldn't properly control when they are evaluated.
174 However, not creating superfluous SAVE_EXPRs requires accurate
175 tracking of readonly-ness all the way down to here, which we
176 cannot always guarantee in practice. So punt in this case. */
177 else if (code
== SAVE_EXPR
)
178 return error_mark_node
;
180 else if (code
== STATEMENT_LIST
)
183 return copy_tree_r (tp
, walk_subtrees
, data
);
186 /* Given a SIZE expression that is self-referential, return an equivalent
187 expression to serve as the actual size expression for a type. */
190 self_referential_size (tree size
)
192 static unsigned HOST_WIDE_INT fnno
= 0;
193 VEC (tree
, heap
) *self_refs
= NULL
;
194 tree param_type_list
= NULL
, param_decl_list
= NULL
;
195 tree t
, ref
, return_type
, fntype
, fnname
, fndecl
;
198 VEC(tree
,gc
) *args
= NULL
;
200 /* Do not factor out simple operations. */
201 t
= skip_simple_constant_arithmetic (size
);
202 if (TREE_CODE (t
) == CALL_EXPR
)
205 /* Collect the list of self-references in the expression. */
206 find_placeholder_in_expr (size
, &self_refs
);
207 gcc_assert (VEC_length (tree
, self_refs
) > 0);
209 /* Obtain a private copy of the expression. */
211 if (walk_tree (&t
, copy_self_referential_tree_r
, NULL
, NULL
) != NULL_TREE
)
215 /* Build the parameter and argument lists in parallel; also
216 substitute the former for the latter in the expression. */
217 args
= VEC_alloc (tree
, gc
, VEC_length (tree
, self_refs
));
218 FOR_EACH_VEC_ELT (tree
, self_refs
, i
, ref
)
220 tree subst
, param_name
, param_type
, param_decl
;
224 /* We shouldn't have true variables here. */
225 gcc_assert (TREE_READONLY (ref
));
228 /* This is the pattern built in ada/make_aligning_type. */
229 else if (TREE_CODE (ref
) == ADDR_EXPR
)
231 /* Default case: the component reference. */
233 subst
= TREE_OPERAND (ref
, 1);
235 sprintf (buf
, "p%d", i
);
236 param_name
= get_identifier (buf
);
237 param_type
= TREE_TYPE (ref
);
239 = build_decl (input_location
, PARM_DECL
, param_name
, param_type
);
240 if (targetm
.calls
.promote_prototypes (NULL_TREE
)
241 && INTEGRAL_TYPE_P (param_type
)
242 && TYPE_PRECISION (param_type
) < TYPE_PRECISION (integer_type_node
))
243 DECL_ARG_TYPE (param_decl
) = integer_type_node
;
245 DECL_ARG_TYPE (param_decl
) = param_type
;
246 DECL_ARTIFICIAL (param_decl
) = 1;
247 TREE_READONLY (param_decl
) = 1;
249 size
= substitute_in_expr (size
, subst
, param_decl
);
251 param_type_list
= tree_cons (NULL_TREE
, param_type
, param_type_list
);
252 param_decl_list
= chainon (param_decl
, param_decl_list
);
253 VEC_quick_push (tree
, args
, ref
);
256 VEC_free (tree
, heap
, self_refs
);
258 /* Append 'void' to indicate that the number of parameters is fixed. */
259 param_type_list
= tree_cons (NULL_TREE
, void_type_node
, param_type_list
);
261 /* The 3 lists have been created in reverse order. */
262 param_type_list
= nreverse (param_type_list
);
263 param_decl_list
= nreverse (param_decl_list
);
265 /* Build the function type. */
266 return_type
= TREE_TYPE (size
);
267 fntype
= build_function_type (return_type
, param_type_list
);
269 /* Build the function declaration. */
270 sprintf (buf
, "SZ"HOST_WIDE_INT_PRINT_UNSIGNED
, fnno
++);
271 fnname
= get_file_function_name (buf
);
272 fndecl
= build_decl (input_location
, FUNCTION_DECL
, fnname
, fntype
);
273 for (t
= param_decl_list
; t
; t
= DECL_CHAIN (t
))
274 DECL_CONTEXT (t
) = fndecl
;
275 DECL_ARGUMENTS (fndecl
) = param_decl_list
;
277 = build_decl (input_location
, RESULT_DECL
, 0, return_type
);
278 DECL_CONTEXT (DECL_RESULT (fndecl
)) = fndecl
;
280 /* The function has been created by the compiler and we don't
281 want to emit debug info for it. */
282 DECL_ARTIFICIAL (fndecl
) = 1;
283 DECL_IGNORED_P (fndecl
) = 1;
285 /* It is supposed to be "const" and never throw. */
286 TREE_READONLY (fndecl
) = 1;
287 TREE_NOTHROW (fndecl
) = 1;
289 /* We want it to be inlined when this is deemed profitable, as
290 well as discarded if every call has been integrated. */
291 DECL_DECLARED_INLINE_P (fndecl
) = 1;
293 /* It is made up of a unique return statement. */
294 DECL_INITIAL (fndecl
) = make_node (BLOCK
);
295 BLOCK_SUPERCONTEXT (DECL_INITIAL (fndecl
)) = fndecl
;
296 t
= build2 (MODIFY_EXPR
, return_type
, DECL_RESULT (fndecl
), size
);
297 DECL_SAVED_TREE (fndecl
) = build1 (RETURN_EXPR
, void_type_node
, t
);
298 TREE_STATIC (fndecl
) = 1;
300 /* Put it onto the list of size functions. */
301 VEC_safe_push (tree
, gc
, size_functions
, fndecl
);
303 /* Replace the original expression with a call to the size function. */
304 return build_call_expr_loc_vec (UNKNOWN_LOCATION
, fndecl
, args
);
307 /* Take, queue and compile all the size functions. It is essential that
308 the size functions be gimplified at the very end of the compilation
309 in order to guarantee transparent handling of self-referential sizes.
310 Otherwise the GENERIC inliner would not be able to inline them back
311 at each of their call sites, thus creating artificial non-constant
312 size expressions which would trigger nasty problems later on. */
315 finalize_size_functions (void)
320 for (i
= 0; VEC_iterate(tree
, size_functions
, i
, fndecl
); i
++)
322 dump_function (TDI_original
, fndecl
);
323 gimplify_function_tree (fndecl
);
324 dump_function (TDI_generic
, fndecl
);
325 cgraph_finalize_function (fndecl
, false);
328 VEC_free (tree
, gc
, size_functions
);
331 /* Return the machine mode to use for a nonscalar of SIZE bits. The
332 mode must be in class MCLASS, and have exactly that many value bits;
333 it may have padding as well. If LIMIT is nonzero, modes of wider
334 than MAX_FIXED_MODE_SIZE will not be used. */
337 mode_for_size (unsigned int size
, enum mode_class mclass
, int limit
)
339 enum machine_mode mode
;
341 if (limit
&& size
> MAX_FIXED_MODE_SIZE
)
344 /* Get the first mode which has this size, in the specified class. */
345 for (mode
= GET_CLASS_NARROWEST_MODE (mclass
); mode
!= VOIDmode
;
346 mode
= GET_MODE_WIDER_MODE (mode
))
347 if (GET_MODE_PRECISION (mode
) == size
)
353 /* Similar, except passed a tree node. */
356 mode_for_size_tree (const_tree size
, enum mode_class mclass
, int limit
)
358 unsigned HOST_WIDE_INT uhwi
;
361 if (!host_integerp (size
, 1))
363 uhwi
= tree_low_cst (size
, 1);
367 return mode_for_size (ui
, mclass
, limit
);
370 /* Similar, but never return BLKmode; return the narrowest mode that
371 contains at least the requested number of value bits. */
374 smallest_mode_for_size (unsigned int size
, enum mode_class mclass
)
376 enum machine_mode mode
;
378 /* Get the first mode which has at least this size, in the
380 for (mode
= GET_CLASS_NARROWEST_MODE (mclass
); mode
!= VOIDmode
;
381 mode
= GET_MODE_WIDER_MODE (mode
))
382 if (GET_MODE_PRECISION (mode
) >= size
)
388 /* Find an integer mode of the exact same size, or BLKmode on failure. */
391 int_mode_for_mode (enum machine_mode mode
)
393 switch (GET_MODE_CLASS (mode
))
396 case MODE_PARTIAL_INT
:
399 case MODE_COMPLEX_INT
:
400 case MODE_COMPLEX_FLOAT
:
402 case MODE_DECIMAL_FLOAT
:
403 case MODE_VECTOR_INT
:
404 case MODE_VECTOR_FLOAT
:
409 case MODE_VECTOR_FRACT
:
410 case MODE_VECTOR_ACCUM
:
411 case MODE_VECTOR_UFRACT
:
412 case MODE_VECTOR_UACCUM
:
413 mode
= mode_for_size (GET_MODE_BITSIZE (mode
), MODE_INT
, 0);
420 /* ... fall through ... */
430 /* Find a mode that is suitable for representing a vector with
431 NUNITS elements of mode INNERMODE. Returns BLKmode if there
432 is no suitable mode. */
435 mode_for_vector (enum machine_mode innermode
, unsigned nunits
)
437 enum machine_mode mode
;
439 /* First, look for a supported vector type. */
440 if (SCALAR_FLOAT_MODE_P (innermode
))
441 mode
= MIN_MODE_VECTOR_FLOAT
;
442 else if (SCALAR_FRACT_MODE_P (innermode
))
443 mode
= MIN_MODE_VECTOR_FRACT
;
444 else if (SCALAR_UFRACT_MODE_P (innermode
))
445 mode
= MIN_MODE_VECTOR_UFRACT
;
446 else if (SCALAR_ACCUM_MODE_P (innermode
))
447 mode
= MIN_MODE_VECTOR_ACCUM
;
448 else if (SCALAR_UACCUM_MODE_P (innermode
))
449 mode
= MIN_MODE_VECTOR_UACCUM
;
451 mode
= MIN_MODE_VECTOR_INT
;
453 /* Do not check vector_mode_supported_p here. We'll do that
454 later in vector_type_mode. */
455 for (; mode
!= VOIDmode
; mode
= GET_MODE_WIDER_MODE (mode
))
456 if (GET_MODE_NUNITS (mode
) == nunits
457 && GET_MODE_INNER (mode
) == innermode
)
460 /* For integers, try mapping it to a same-sized scalar mode. */
462 && GET_MODE_CLASS (innermode
) == MODE_INT
)
463 mode
= mode_for_size (nunits
* GET_MODE_BITSIZE (innermode
),
467 || (GET_MODE_CLASS (mode
) == MODE_INT
468 && !have_regs_of_mode
[mode
]))
474 /* Return the alignment of MODE. This will be bounded by 1 and
475 BIGGEST_ALIGNMENT. */
478 get_mode_alignment (enum machine_mode mode
)
480 return MIN (BIGGEST_ALIGNMENT
, MAX (1, mode_base_align
[mode
]*BITS_PER_UNIT
));
483 /* Return the natural mode of an array, given that it is SIZE bytes in
484 total and has elements of type ELEM_TYPE. */
486 static enum machine_mode
487 mode_for_array (tree elem_type
, tree size
)
490 unsigned HOST_WIDE_INT int_size
, int_elem_size
;
493 /* One-element arrays get the component type's mode. */
494 elem_size
= TYPE_SIZE (elem_type
);
495 if (simple_cst_equal (size
, elem_size
))
496 return TYPE_MODE (elem_type
);
499 if (host_integerp (size
, 1) && host_integerp (elem_size
, 1))
501 int_size
= tree_low_cst (size
, 1);
502 int_elem_size
= tree_low_cst (elem_size
, 1);
503 if (int_elem_size
> 0
504 && int_size
% int_elem_size
== 0
505 && targetm
.array_mode_supported_p (TYPE_MODE (elem_type
),
506 int_size
/ int_elem_size
))
509 return mode_for_size_tree (size
, MODE_INT
, limit_p
);
512 /* Subroutine of layout_decl: Force alignment required for the data type.
513 But if the decl itself wants greater alignment, don't override that. */
516 do_type_align (tree type
, tree decl
)
518 if (TYPE_ALIGN (type
) > DECL_ALIGN (decl
))
520 DECL_ALIGN (decl
) = TYPE_ALIGN (type
);
521 if (TREE_CODE (decl
) == FIELD_DECL
)
522 DECL_USER_ALIGN (decl
) = TYPE_USER_ALIGN (type
);
526 /* Set the size, mode and alignment of a ..._DECL node.
527 TYPE_DECL does need this for C++.
528 Note that LABEL_DECL and CONST_DECL nodes do not need this,
529 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
530 Don't call layout_decl for them.
532 KNOWN_ALIGN is the amount of alignment we can assume this
533 decl has with no special effort. It is relevant only for FIELD_DECLs
534 and depends on the previous fields.
535 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
536 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
537 the record will be aligned to suit. */
540 layout_decl (tree decl
, unsigned int known_align
)
542 tree type
= TREE_TYPE (decl
);
543 enum tree_code code
= TREE_CODE (decl
);
545 location_t loc
= DECL_SOURCE_LOCATION (decl
);
547 if (code
== CONST_DECL
)
550 gcc_assert (code
== VAR_DECL
|| code
== PARM_DECL
|| code
== RESULT_DECL
551 || code
== TYPE_DECL
||code
== FIELD_DECL
);
553 rtl
= DECL_RTL_IF_SET (decl
);
555 if (type
== error_mark_node
)
556 type
= void_type_node
;
558 /* Usually the size and mode come from the data type without change,
559 however, the front-end may set the explicit width of the field, so its
560 size may not be the same as the size of its type. This happens with
561 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
562 also happens with other fields. For example, the C++ front-end creates
563 zero-sized fields corresponding to empty base classes, and depends on
564 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
565 size in bytes from the size in bits. If we have already set the mode,
566 don't set it again since we can be called twice for FIELD_DECLs. */
568 DECL_UNSIGNED (decl
) = TYPE_UNSIGNED (type
);
569 if (DECL_MODE (decl
) == VOIDmode
)
570 DECL_MODE (decl
) = TYPE_MODE (type
);
572 if (DECL_SIZE (decl
) == 0)
574 DECL_SIZE (decl
) = TYPE_SIZE (type
);
575 DECL_SIZE_UNIT (decl
) = TYPE_SIZE_UNIT (type
);
577 else if (DECL_SIZE_UNIT (decl
) == 0)
578 DECL_SIZE_UNIT (decl
)
579 = fold_convert_loc (loc
, sizetype
,
580 size_binop_loc (loc
, CEIL_DIV_EXPR
, DECL_SIZE (decl
),
583 if (code
!= FIELD_DECL
)
584 /* For non-fields, update the alignment from the type. */
585 do_type_align (type
, decl
);
587 /* For fields, it's a bit more complicated... */
589 bool old_user_align
= DECL_USER_ALIGN (decl
);
590 bool zero_bitfield
= false;
591 bool packed_p
= DECL_PACKED (decl
);
594 if (DECL_BIT_FIELD (decl
))
596 DECL_BIT_FIELD_TYPE (decl
) = type
;
598 /* A zero-length bit-field affects the alignment of the next
599 field. In essence such bit-fields are not influenced by
600 any packing due to #pragma pack or attribute packed. */
601 if (integer_zerop (DECL_SIZE (decl
))
602 && ! targetm
.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl
)))
604 zero_bitfield
= true;
606 #ifdef PCC_BITFIELD_TYPE_MATTERS
607 if (PCC_BITFIELD_TYPE_MATTERS
)
608 do_type_align (type
, decl
);
612 #ifdef EMPTY_FIELD_BOUNDARY
613 if (EMPTY_FIELD_BOUNDARY
> DECL_ALIGN (decl
))
615 DECL_ALIGN (decl
) = EMPTY_FIELD_BOUNDARY
;
616 DECL_USER_ALIGN (decl
) = 0;
622 /* See if we can use an ordinary integer mode for a bit-field.
623 Conditions are: a fixed size that is correct for another mode,
624 occupying a complete byte or bytes on proper boundary,
625 and not volatile or not -fstrict-volatile-bitfields. */
626 if (TYPE_SIZE (type
) != 0
627 && TREE_CODE (TYPE_SIZE (type
)) == INTEGER_CST
628 && GET_MODE_CLASS (TYPE_MODE (type
)) == MODE_INT
629 && !(TREE_THIS_VOLATILE (decl
)
630 && flag_strict_volatile_bitfields
> 0))
632 enum machine_mode xmode
633 = mode_for_size_tree (DECL_SIZE (decl
), MODE_INT
, 1);
634 unsigned int xalign
= GET_MODE_ALIGNMENT (xmode
);
637 && !(xalign
> BITS_PER_UNIT
&& DECL_PACKED (decl
))
638 && (known_align
== 0 || known_align
>= xalign
))
640 DECL_ALIGN (decl
) = MAX (xalign
, DECL_ALIGN (decl
));
641 DECL_MODE (decl
) = xmode
;
642 DECL_BIT_FIELD (decl
) = 0;
646 /* Turn off DECL_BIT_FIELD if we won't need it set. */
647 if (TYPE_MODE (type
) == BLKmode
&& DECL_MODE (decl
) == BLKmode
648 && known_align
>= TYPE_ALIGN (type
)
649 && DECL_ALIGN (decl
) >= TYPE_ALIGN (type
))
650 DECL_BIT_FIELD (decl
) = 0;
652 else if (packed_p
&& DECL_USER_ALIGN (decl
))
653 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
654 round up; we'll reduce it again below. We want packing to
655 supersede USER_ALIGN inherited from the type, but defer to
656 alignment explicitly specified on the field decl. */;
658 do_type_align (type
, decl
);
660 /* If the field is packed and not explicitly aligned, give it the
661 minimum alignment. Note that do_type_align may set
662 DECL_USER_ALIGN, so we need to check old_user_align instead. */
665 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), BITS_PER_UNIT
);
667 if (! packed_p
&& ! DECL_USER_ALIGN (decl
))
669 /* Some targets (i.e. i386, VMS) limit struct field alignment
670 to a lower boundary than alignment of variables unless
671 it was overridden by attribute aligned. */
672 #ifdef BIGGEST_FIELD_ALIGNMENT
674 = MIN (DECL_ALIGN (decl
), (unsigned) BIGGEST_FIELD_ALIGNMENT
);
676 #ifdef ADJUST_FIELD_ALIGN
677 DECL_ALIGN (decl
) = ADJUST_FIELD_ALIGN (decl
, DECL_ALIGN (decl
));
682 mfa
= initial_max_fld_align
* BITS_PER_UNIT
;
684 mfa
= maximum_field_alignment
;
685 /* Should this be controlled by DECL_USER_ALIGN, too? */
687 DECL_ALIGN (decl
) = MIN (DECL_ALIGN (decl
), mfa
);
690 /* Evaluate nonconstant size only once, either now or as soon as safe. */
691 if (DECL_SIZE (decl
) != 0 && TREE_CODE (DECL_SIZE (decl
)) != INTEGER_CST
)
692 DECL_SIZE (decl
) = variable_size (DECL_SIZE (decl
));
693 if (DECL_SIZE_UNIT (decl
) != 0
694 && TREE_CODE (DECL_SIZE_UNIT (decl
)) != INTEGER_CST
)
695 DECL_SIZE_UNIT (decl
) = variable_size (DECL_SIZE_UNIT (decl
));
697 /* If requested, warn about definitions of large data objects. */
699 && (code
== VAR_DECL
|| code
== PARM_DECL
)
700 && ! DECL_EXTERNAL (decl
))
702 tree size
= DECL_SIZE_UNIT (decl
);
704 if (size
!= 0 && TREE_CODE (size
) == INTEGER_CST
705 && compare_tree_int (size
, larger_than_size
) > 0)
707 int size_as_int
= TREE_INT_CST_LOW (size
);
709 if (compare_tree_int (size
, size_as_int
) == 0)
710 warning (OPT_Wlarger_than_
, "size of %q+D is %d bytes", decl
, size_as_int
);
712 warning (OPT_Wlarger_than_
, "size of %q+D is larger than %wd bytes",
713 decl
, larger_than_size
);
717 /* If the RTL was already set, update its mode and mem attributes. */
720 PUT_MODE (rtl
, DECL_MODE (decl
));
721 SET_DECL_RTL (decl
, 0);
722 set_mem_attributes (rtl
, decl
, 1);
723 SET_DECL_RTL (decl
, rtl
);
727 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
728 a previous call to layout_decl and calls it again. */
731 relayout_decl (tree decl
)
733 DECL_SIZE (decl
) = DECL_SIZE_UNIT (decl
) = 0;
734 DECL_MODE (decl
) = VOIDmode
;
735 if (!DECL_USER_ALIGN (decl
))
736 DECL_ALIGN (decl
) = 0;
737 SET_DECL_RTL (decl
, 0);
739 layout_decl (decl
, 0);
742 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
743 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
744 is to be passed to all other layout functions for this record. It is the
745 responsibility of the caller to call `free' for the storage returned.
746 Note that garbage collection is not permitted until we finish laying
750 start_record_layout (tree t
)
752 record_layout_info rli
= XNEW (struct record_layout_info_s
);
756 /* If the type has a minimum specified alignment (via an attribute
757 declaration, for example) use it -- otherwise, start with a
758 one-byte alignment. */
759 rli
->record_align
= MAX (BITS_PER_UNIT
, TYPE_ALIGN (t
));
760 rli
->unpacked_align
= rli
->record_align
;
761 rli
->offset_align
= MAX (rli
->record_align
, BIGGEST_ALIGNMENT
);
763 #ifdef STRUCTURE_SIZE_BOUNDARY
764 /* Packed structures don't need to have minimum size. */
765 if (! TYPE_PACKED (t
))
769 /* #pragma pack overrides STRUCTURE_SIZE_BOUNDARY. */
770 tmp
= (unsigned) STRUCTURE_SIZE_BOUNDARY
;
771 if (maximum_field_alignment
!= 0)
772 tmp
= MIN (tmp
, maximum_field_alignment
);
773 rli
->record_align
= MAX (rli
->record_align
, tmp
);
777 rli
->offset
= size_zero_node
;
778 rli
->bitpos
= bitsize_zero_node
;
780 rli
->pending_statics
= NULL
;
781 rli
->packed_maybe_necessary
= 0;
782 rli
->remaining_in_alignment
= 0;
787 /* These four routines perform computations that convert between
788 the offset/bitpos forms and byte and bit offsets. */
791 bit_from_pos (tree offset
, tree bitpos
)
793 return size_binop (PLUS_EXPR
, bitpos
,
794 size_binop (MULT_EXPR
,
795 fold_convert (bitsizetype
, offset
),
800 byte_from_pos (tree offset
, tree bitpos
)
802 return size_binop (PLUS_EXPR
, offset
,
803 fold_convert (sizetype
,
804 size_binop (TRUNC_DIV_EXPR
, bitpos
,
805 bitsize_unit_node
)));
809 pos_from_bit (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
,
812 *poffset
= size_binop (MULT_EXPR
,
813 fold_convert (sizetype
,
814 size_binop (FLOOR_DIV_EXPR
, pos
,
815 bitsize_int (off_align
))),
816 size_int (off_align
/ BITS_PER_UNIT
));
817 *pbitpos
= size_binop (FLOOR_MOD_EXPR
, pos
, bitsize_int (off_align
));
820 /* Given a pointer to bit and byte offsets and an offset alignment,
821 normalize the offsets so they are within the alignment. */
824 normalize_offset (tree
*poffset
, tree
*pbitpos
, unsigned int off_align
)
826 /* If the bit position is now larger than it should be, adjust it
828 if (compare_tree_int (*pbitpos
, off_align
) >= 0)
830 tree extra_aligns
= size_binop (FLOOR_DIV_EXPR
, *pbitpos
,
831 bitsize_int (off_align
));
834 = size_binop (PLUS_EXPR
, *poffset
,
835 size_binop (MULT_EXPR
,
836 fold_convert (sizetype
, extra_aligns
),
837 size_int (off_align
/ BITS_PER_UNIT
)));
840 = size_binop (FLOOR_MOD_EXPR
, *pbitpos
, bitsize_int (off_align
));
844 /* Print debugging information about the information in RLI. */
847 debug_rli (record_layout_info rli
)
849 print_node_brief (stderr
, "type", rli
->t
, 0);
850 print_node_brief (stderr
, "\noffset", rli
->offset
, 0);
851 print_node_brief (stderr
, " bitpos", rli
->bitpos
, 0);
853 fprintf (stderr
, "\naligns: rec = %u, unpack = %u, off = %u\n",
854 rli
->record_align
, rli
->unpacked_align
,
857 /* The ms_struct code is the only that uses this. */
858 if (targetm
.ms_bitfield_layout_p (rli
->t
))
859 fprintf (stderr
, "remaining in alignment = %u\n", rli
->remaining_in_alignment
);
861 if (rli
->packed_maybe_necessary
)
862 fprintf (stderr
, "packed may be necessary\n");
864 if (!VEC_empty (tree
, rli
->pending_statics
))
866 fprintf (stderr
, "pending statics:\n");
867 debug_vec_tree (rli
->pending_statics
);
871 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
872 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
875 normalize_rli (record_layout_info rli
)
877 normalize_offset (&rli
->offset
, &rli
->bitpos
, rli
->offset_align
);
880 /* Returns the size in bytes allocated so far. */
883 rli_size_unit_so_far (record_layout_info rli
)
885 return byte_from_pos (rli
->offset
, rli
->bitpos
);
888 /* Returns the size in bits allocated so far. */
891 rli_size_so_far (record_layout_info rli
)
893 return bit_from_pos (rli
->offset
, rli
->bitpos
);
896 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
897 the next available location within the record is given by KNOWN_ALIGN.
898 Update the variable alignment fields in RLI, and return the alignment
899 to give the FIELD. */
902 update_alignment_for_field (record_layout_info rli
, tree field
,
903 unsigned int known_align
)
905 /* The alignment required for FIELD. */
906 unsigned int desired_align
;
907 /* The type of this field. */
908 tree type
= TREE_TYPE (field
);
909 /* True if the field was explicitly aligned by the user. */
913 /* Do not attempt to align an ERROR_MARK node */
914 if (TREE_CODE (type
) == ERROR_MARK
)
917 /* Lay out the field so we know what alignment it needs. */
918 layout_decl (field
, known_align
);
919 desired_align
= DECL_ALIGN (field
);
920 user_align
= DECL_USER_ALIGN (field
);
922 is_bitfield
= (type
!= error_mark_node
923 && DECL_BIT_FIELD_TYPE (field
)
924 && ! integer_zerop (TYPE_SIZE (type
)));
926 /* Record must have at least as much alignment as any field.
927 Otherwise, the alignment of the field within the record is
929 if (targetm
.ms_bitfield_layout_p (rli
->t
))
931 /* Here, the alignment of the underlying type of a bitfield can
932 affect the alignment of a record; even a zero-sized field
933 can do this. The alignment should be to the alignment of
934 the type, except that for zero-size bitfields this only
935 applies if there was an immediately prior, nonzero-size
936 bitfield. (That's the way it is, experimentally.) */
937 if ((!is_bitfield
&& !DECL_PACKED (field
))
938 || (!integer_zerop (DECL_SIZE (field
))
939 ? !DECL_PACKED (field
)
941 && DECL_BIT_FIELD_TYPE (rli
->prev_field
)
942 && ! integer_zerop (DECL_SIZE (rli
->prev_field
)))))
944 unsigned int type_align
= TYPE_ALIGN (type
);
945 type_align
= MAX (type_align
, desired_align
);
946 if (maximum_field_alignment
!= 0)
947 type_align
= MIN (type_align
, maximum_field_alignment
);
948 rli
->record_align
= MAX (rli
->record_align
, type_align
);
949 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
952 #ifdef PCC_BITFIELD_TYPE_MATTERS
953 else if (is_bitfield
&& PCC_BITFIELD_TYPE_MATTERS
)
955 /* Named bit-fields cause the entire structure to have the
956 alignment implied by their type. Some targets also apply the same
957 rules to unnamed bitfields. */
958 if (DECL_NAME (field
) != 0
959 || targetm
.align_anon_bitfield ())
961 unsigned int type_align
= TYPE_ALIGN (type
);
963 #ifdef ADJUST_FIELD_ALIGN
964 if (! TYPE_USER_ALIGN (type
))
965 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
968 /* Targets might chose to handle unnamed and hence possibly
969 zero-width bitfield. Those are not influenced by #pragmas
970 or packed attributes. */
971 if (integer_zerop (DECL_SIZE (field
)))
973 if (initial_max_fld_align
)
974 type_align
= MIN (type_align
,
975 initial_max_fld_align
* BITS_PER_UNIT
);
977 else if (maximum_field_alignment
!= 0)
978 type_align
= MIN (type_align
, maximum_field_alignment
);
979 else if (DECL_PACKED (field
))
980 type_align
= MIN (type_align
, BITS_PER_UNIT
);
982 /* The alignment of the record is increased to the maximum
983 of the current alignment, the alignment indicated on the
984 field (i.e., the alignment specified by an __aligned__
985 attribute), and the alignment indicated by the type of
987 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
988 rli
->record_align
= MAX (rli
->record_align
, type_align
);
991 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
992 user_align
|= TYPE_USER_ALIGN (type
);
998 rli
->record_align
= MAX (rli
->record_align
, desired_align
);
999 rli
->unpacked_align
= MAX (rli
->unpacked_align
, TYPE_ALIGN (type
));
1002 TYPE_USER_ALIGN (rli
->t
) |= user_align
;
1004 return desired_align
;
1007 /* Called from place_field to handle unions. */
1010 place_union_field (record_layout_info rli
, tree field
)
1012 update_alignment_for_field (rli
, field
, /*known_align=*/0);
1014 DECL_FIELD_OFFSET (field
) = size_zero_node
;
1015 DECL_FIELD_BIT_OFFSET (field
) = bitsize_zero_node
;
1016 SET_DECL_OFFSET_ALIGN (field
, BIGGEST_ALIGNMENT
);
1018 /* If this is an ERROR_MARK return *after* having set the
1019 field at the start of the union. This helps when parsing
1021 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
)
1024 /* We assume the union's size will be a multiple of a byte so we don't
1025 bother with BITPOS. */
1026 if (TREE_CODE (rli
->t
) == UNION_TYPE
)
1027 rli
->offset
= size_binop (MAX_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1028 else if (TREE_CODE (rli
->t
) == QUAL_UNION_TYPE
)
1029 rli
->offset
= fold_build3 (COND_EXPR
, sizetype
, DECL_QUALIFIER (field
),
1030 DECL_SIZE_UNIT (field
), rli
->offset
);
1033 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
1034 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
1035 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
1036 units of alignment than the underlying TYPE. */
1038 excess_unit_span (HOST_WIDE_INT byte_offset
, HOST_WIDE_INT bit_offset
,
1039 HOST_WIDE_INT size
, HOST_WIDE_INT align
, tree type
)
1041 /* Note that the calculation of OFFSET might overflow; we calculate it so
1042 that we still get the right result as long as ALIGN is a power of two. */
1043 unsigned HOST_WIDE_INT offset
= byte_offset
* BITS_PER_UNIT
+ bit_offset
;
1045 offset
= offset
% align
;
1046 return ((offset
+ size
+ align
- 1) / align
1047 > ((unsigned HOST_WIDE_INT
) tree_low_cst (TYPE_SIZE (type
), 1)
1052 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
1053 is a FIELD_DECL to be added after those fields already present in
1054 T. (FIELD is not actually added to the TYPE_FIELDS list here;
1055 callers that desire that behavior must manually perform that step.) */
1058 place_field (record_layout_info rli
, tree field
)
1060 /* The alignment required for FIELD. */
1061 unsigned int desired_align
;
1062 /* The alignment FIELD would have if we just dropped it into the
1063 record as it presently stands. */
1064 unsigned int known_align
;
1065 unsigned int actual_align
;
1066 /* The type of this field. */
1067 tree type
= TREE_TYPE (field
);
1069 gcc_assert (TREE_CODE (field
) != ERROR_MARK
);
1071 /* If FIELD is static, then treat it like a separate variable, not
1072 really like a structure field. If it is a FUNCTION_DECL, it's a
1073 method. In both cases, all we do is lay out the decl, and we do
1074 it *after* the record is laid out. */
1075 if (TREE_CODE (field
) == VAR_DECL
)
1077 VEC_safe_push (tree
, gc
, rli
->pending_statics
, field
);
1081 /* Enumerators and enum types which are local to this class need not
1082 be laid out. Likewise for initialized constant fields. */
1083 else if (TREE_CODE (field
) != FIELD_DECL
)
1086 /* Unions are laid out very differently than records, so split
1087 that code off to another function. */
1088 else if (TREE_CODE (rli
->t
) != RECORD_TYPE
)
1090 place_union_field (rli
, field
);
1094 else if (TREE_CODE (type
) == ERROR_MARK
)
1096 /* Place this field at the current allocation position, so we
1097 maintain monotonicity. */
1098 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1099 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1100 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1104 /* Work out the known alignment so far. Note that A & (-A) is the
1105 value of the least-significant bit in A that is one. */
1106 if (! integer_zerop (rli
->bitpos
))
1107 known_align
= (tree_low_cst (rli
->bitpos
, 1)
1108 & - tree_low_cst (rli
->bitpos
, 1));
1109 else if (integer_zerop (rli
->offset
))
1111 else if (host_integerp (rli
->offset
, 1))
1112 known_align
= (BITS_PER_UNIT
1113 * (tree_low_cst (rli
->offset
, 1)
1114 & - tree_low_cst (rli
->offset
, 1)));
1116 known_align
= rli
->offset_align
;
1118 desired_align
= update_alignment_for_field (rli
, field
, known_align
);
1119 if (known_align
== 0)
1120 known_align
= MAX (BIGGEST_ALIGNMENT
, rli
->record_align
);
1122 if (warn_packed
&& DECL_PACKED (field
))
1124 if (known_align
>= TYPE_ALIGN (type
))
1126 if (TYPE_ALIGN (type
) > desired_align
)
1128 if (STRICT_ALIGNMENT
)
1129 warning (OPT_Wattributes
, "packed attribute causes "
1130 "inefficient alignment for %q+D", field
);
1131 /* Don't warn if DECL_PACKED was set by the type. */
1132 else if (!TYPE_PACKED (rli
->t
))
1133 warning (OPT_Wattributes
, "packed attribute is "
1134 "unnecessary for %q+D", field
);
1138 rli
->packed_maybe_necessary
= 1;
1141 /* Does this field automatically have alignment it needs by virtue
1142 of the fields that precede it and the record's own alignment?
1143 We already align ms_struct fields, so don't re-align them. */
1144 if (known_align
< desired_align
1145 && !targetm
.ms_bitfield_layout_p (rli
->t
))
1147 /* No, we need to skip space before this field.
1148 Bump the cumulative size to multiple of field alignment. */
1150 if (DECL_SOURCE_LOCATION (field
) != BUILTINS_LOCATION
)
1151 warning (OPT_Wpadded
, "padding struct to align %q+D", field
);
1153 /* If the alignment is still within offset_align, just align
1154 the bit position. */
1155 if (desired_align
< rli
->offset_align
)
1156 rli
->bitpos
= round_up (rli
->bitpos
, desired_align
);
1159 /* First adjust OFFSET by the partial bits, then align. */
1161 = size_binop (PLUS_EXPR
, rli
->offset
,
1162 fold_convert (sizetype
,
1163 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1164 bitsize_unit_node
)));
1165 rli
->bitpos
= bitsize_zero_node
;
1167 rli
->offset
= round_up (rli
->offset
, desired_align
/ BITS_PER_UNIT
);
1170 if (! TREE_CONSTANT (rli
->offset
))
1171 rli
->offset_align
= desired_align
;
1175 /* Handle compatibility with PCC. Note that if the record has any
1176 variable-sized fields, we need not worry about compatibility. */
1177 #ifdef PCC_BITFIELD_TYPE_MATTERS
1178 if (PCC_BITFIELD_TYPE_MATTERS
1179 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
1180 && TREE_CODE (field
) == FIELD_DECL
1181 && type
!= error_mark_node
1182 && DECL_BIT_FIELD (field
)
1183 && (! DECL_PACKED (field
)
1184 /* Enter for these packed fields only to issue a warning. */
1185 || TYPE_ALIGN (type
) <= BITS_PER_UNIT
)
1186 && maximum_field_alignment
== 0
1187 && ! integer_zerop (DECL_SIZE (field
))
1188 && host_integerp (DECL_SIZE (field
), 1)
1189 && host_integerp (rli
->offset
, 1)
1190 && host_integerp (TYPE_SIZE (type
), 1))
1192 unsigned int type_align
= TYPE_ALIGN (type
);
1193 tree dsize
= DECL_SIZE (field
);
1194 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
1195 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
1196 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
1198 #ifdef ADJUST_FIELD_ALIGN
1199 if (! TYPE_USER_ALIGN (type
))
1200 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
1203 /* A bit field may not span more units of alignment of its type
1204 than its type itself. Advance to next boundary if necessary. */
1205 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
1207 if (DECL_PACKED (field
))
1209 if (warn_packed_bitfield_compat
== 1)
1212 "offset of packed bit-field %qD has changed in GCC 4.4",
1216 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1219 if (! DECL_PACKED (field
))
1220 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
1224 #ifdef BITFIELD_NBYTES_LIMITED
1225 if (BITFIELD_NBYTES_LIMITED
1226 && ! targetm
.ms_bitfield_layout_p (rli
->t
)
1227 && TREE_CODE (field
) == FIELD_DECL
1228 && type
!= error_mark_node
1229 && DECL_BIT_FIELD_TYPE (field
)
1230 && ! DECL_PACKED (field
)
1231 && ! integer_zerop (DECL_SIZE (field
))
1232 && host_integerp (DECL_SIZE (field
), 1)
1233 && host_integerp (rli
->offset
, 1)
1234 && host_integerp (TYPE_SIZE (type
), 1))
1236 unsigned int type_align
= TYPE_ALIGN (type
);
1237 tree dsize
= DECL_SIZE (field
);
1238 HOST_WIDE_INT field_size
= tree_low_cst (dsize
, 1);
1239 HOST_WIDE_INT offset
= tree_low_cst (rli
->offset
, 0);
1240 HOST_WIDE_INT bit_offset
= tree_low_cst (rli
->bitpos
, 0);
1242 #ifdef ADJUST_FIELD_ALIGN
1243 if (! TYPE_USER_ALIGN (type
))
1244 type_align
= ADJUST_FIELD_ALIGN (field
, type_align
);
1247 if (maximum_field_alignment
!= 0)
1248 type_align
= MIN (type_align
, maximum_field_alignment
);
1249 /* ??? This test is opposite the test in the containing if
1250 statement, so this code is unreachable currently. */
1251 else if (DECL_PACKED (field
))
1252 type_align
= MIN (type_align
, BITS_PER_UNIT
);
1254 /* A bit field may not span the unit of alignment of its type.
1255 Advance to next boundary if necessary. */
1256 if (excess_unit_span (offset
, bit_offset
, field_size
, type_align
, type
))
1257 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1259 TYPE_USER_ALIGN (rli
->t
) |= TYPE_USER_ALIGN (type
);
1263 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1265 When a bit field is inserted into a packed record, the whole
1266 size of the underlying type is used by one or more same-size
1267 adjacent bitfields. (That is, if its long:3, 32 bits is
1268 used in the record, and any additional adjacent long bitfields are
1269 packed into the same chunk of 32 bits. However, if the size
1270 changes, a new field of that size is allocated.) In an unpacked
1271 record, this is the same as using alignment, but not equivalent
1274 Note: for compatibility, we use the type size, not the type alignment
1275 to determine alignment, since that matches the documentation */
1277 if (targetm
.ms_bitfield_layout_p (rli
->t
))
1279 tree prev_saved
= rli
->prev_field
;
1280 tree prev_type
= prev_saved
? DECL_BIT_FIELD_TYPE (prev_saved
) : NULL
;
1282 /* This is a bitfield if it exists. */
1283 if (rli
->prev_field
)
1285 /* If both are bitfields, nonzero, and the same size, this is
1286 the middle of a run. Zero declared size fields are special
1287 and handled as "end of run". (Note: it's nonzero declared
1288 size, but equal type sizes!) (Since we know that both
1289 the current and previous fields are bitfields by the
1290 time we check it, DECL_SIZE must be present for both.) */
1291 if (DECL_BIT_FIELD_TYPE (field
)
1292 && !integer_zerop (DECL_SIZE (field
))
1293 && !integer_zerop (DECL_SIZE (rli
->prev_field
))
1294 && host_integerp (DECL_SIZE (rli
->prev_field
), 0)
1295 && host_integerp (TYPE_SIZE (type
), 0)
1296 && simple_cst_equal (TYPE_SIZE (type
), TYPE_SIZE (prev_type
)))
1298 /* We're in the middle of a run of equal type size fields; make
1299 sure we realign if we run out of bits. (Not decl size,
1301 HOST_WIDE_INT bitsize
= tree_low_cst (DECL_SIZE (field
), 1);
1303 if (rli
->remaining_in_alignment
< bitsize
)
1305 HOST_WIDE_INT typesize
= tree_low_cst (TYPE_SIZE (type
), 1);
1307 /* out of bits; bump up to next 'word'. */
1309 = size_binop (PLUS_EXPR
, rli
->bitpos
,
1310 bitsize_int (rli
->remaining_in_alignment
));
1311 rli
->prev_field
= field
;
1312 if (typesize
< bitsize
)
1313 rli
->remaining_in_alignment
= 0;
1315 rli
->remaining_in_alignment
= typesize
- bitsize
;
1318 rli
->remaining_in_alignment
-= bitsize
;
1322 /* End of a run: if leaving a run of bitfields of the same type
1323 size, we have to "use up" the rest of the bits of the type
1326 Compute the new position as the sum of the size for the prior
1327 type and where we first started working on that type.
1328 Note: since the beginning of the field was aligned then
1329 of course the end will be too. No round needed. */
1331 if (!integer_zerop (DECL_SIZE (rli
->prev_field
)))
1334 = size_binop (PLUS_EXPR
, rli
->bitpos
,
1335 bitsize_int (rli
->remaining_in_alignment
));
1338 /* We "use up" size zero fields; the code below should behave
1339 as if the prior field was not a bitfield. */
1342 /* Cause a new bitfield to be captured, either this time (if
1343 currently a bitfield) or next time we see one. */
1344 if (!DECL_BIT_FIELD_TYPE(field
)
1345 || integer_zerop (DECL_SIZE (field
)))
1346 rli
->prev_field
= NULL
;
1349 normalize_rli (rli
);
1352 /* If we're starting a new run of same size type bitfields
1353 (or a run of non-bitfields), set up the "first of the run"
1356 That is, if the current field is not a bitfield, or if there
1357 was a prior bitfield the type sizes differ, or if there wasn't
1358 a prior bitfield the size of the current field is nonzero.
1360 Note: we must be sure to test ONLY the type size if there was
1361 a prior bitfield and ONLY for the current field being zero if
1364 if (!DECL_BIT_FIELD_TYPE (field
)
1365 || (prev_saved
!= NULL
1366 ? !simple_cst_equal (TYPE_SIZE (type
), TYPE_SIZE (prev_type
))
1367 : !integer_zerop (DECL_SIZE (field
)) ))
1369 /* Never smaller than a byte for compatibility. */
1370 unsigned int type_align
= BITS_PER_UNIT
;
1372 /* (When not a bitfield), we could be seeing a flex array (with
1373 no DECL_SIZE). Since we won't be using remaining_in_alignment
1374 until we see a bitfield (and come by here again) we just skip
1376 if (DECL_SIZE (field
) != NULL
1377 && host_integerp (TYPE_SIZE (TREE_TYPE (field
)), 1)
1378 && host_integerp (DECL_SIZE (field
), 1))
1380 unsigned HOST_WIDE_INT bitsize
1381 = tree_low_cst (DECL_SIZE (field
), 1);
1382 unsigned HOST_WIDE_INT typesize
1383 = tree_low_cst (TYPE_SIZE (TREE_TYPE (field
)), 1);
1385 if (typesize
< bitsize
)
1386 rli
->remaining_in_alignment
= 0;
1388 rli
->remaining_in_alignment
= typesize
- bitsize
;
1391 /* Now align (conventionally) for the new type. */
1392 type_align
= TYPE_ALIGN (TREE_TYPE (field
));
1394 if (maximum_field_alignment
!= 0)
1395 type_align
= MIN (type_align
, maximum_field_alignment
);
1397 rli
->bitpos
= round_up (rli
->bitpos
, type_align
);
1399 /* If we really aligned, don't allow subsequent bitfields
1401 rli
->prev_field
= NULL
;
1405 /* Offset so far becomes the position of this field after normalizing. */
1406 normalize_rli (rli
);
1407 DECL_FIELD_OFFSET (field
) = rli
->offset
;
1408 DECL_FIELD_BIT_OFFSET (field
) = rli
->bitpos
;
1409 SET_DECL_OFFSET_ALIGN (field
, rli
->offset_align
);
1411 /* If this field ended up more aligned than we thought it would be (we
1412 approximate this by seeing if its position changed), lay out the field
1413 again; perhaps we can use an integral mode for it now. */
1414 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field
)))
1415 actual_align
= (tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1)
1416 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field
), 1));
1417 else if (integer_zerop (DECL_FIELD_OFFSET (field
)))
1418 actual_align
= MAX (BIGGEST_ALIGNMENT
, rli
->record_align
);
1419 else if (host_integerp (DECL_FIELD_OFFSET (field
), 1))
1420 actual_align
= (BITS_PER_UNIT
1421 * (tree_low_cst (DECL_FIELD_OFFSET (field
), 1)
1422 & - tree_low_cst (DECL_FIELD_OFFSET (field
), 1)));
1424 actual_align
= DECL_OFFSET_ALIGN (field
);
1425 /* ACTUAL_ALIGN is still the actual alignment *within the record* .
1426 store / extract bit field operations will check the alignment of the
1427 record against the mode of bit fields. */
1429 if (known_align
!= actual_align
)
1430 layout_decl (field
, actual_align
);
1432 if (rli
->prev_field
== NULL
&& DECL_BIT_FIELD_TYPE (field
))
1433 rli
->prev_field
= field
;
1435 /* Now add size of this field to the size of the record. If the size is
1436 not constant, treat the field as being a multiple of bytes and just
1437 adjust the offset, resetting the bit position. Otherwise, apportion the
1438 size amongst the bit position and offset. First handle the case of an
1439 unspecified size, which can happen when we have an invalid nested struct
1440 definition, such as struct j { struct j { int i; } }. The error message
1441 is printed in finish_struct. */
1442 if (DECL_SIZE (field
) == 0)
1444 else if (TREE_CODE (DECL_SIZE (field
)) != INTEGER_CST
1445 || TREE_OVERFLOW (DECL_SIZE (field
)))
1448 = size_binop (PLUS_EXPR
, rli
->offset
,
1449 fold_convert (sizetype
,
1450 size_binop (CEIL_DIV_EXPR
, rli
->bitpos
,
1451 bitsize_unit_node
)));
1453 = size_binop (PLUS_EXPR
, rli
->offset
, DECL_SIZE_UNIT (field
));
1454 rli
->bitpos
= bitsize_zero_node
;
1455 rli
->offset_align
= MIN (rli
->offset_align
, desired_align
);
1457 else if (targetm
.ms_bitfield_layout_p (rli
->t
))
1459 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1461 /* If we ended a bitfield before the full length of the type then
1462 pad the struct out to the full length of the last type. */
1463 if ((DECL_CHAIN (field
) == NULL
1464 || TREE_CODE (DECL_CHAIN (field
)) != FIELD_DECL
)
1465 && DECL_BIT_FIELD_TYPE (field
)
1466 && !integer_zerop (DECL_SIZE (field
)))
1467 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
,
1468 bitsize_int (rli
->remaining_in_alignment
));
1470 normalize_rli (rli
);
1474 rli
->bitpos
= size_binop (PLUS_EXPR
, rli
->bitpos
, DECL_SIZE (field
));
1475 normalize_rli (rli
);
1479 /* Assuming that all the fields have been laid out, this function uses
1480 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1481 indicated by RLI. */
1484 finalize_record_size (record_layout_info rli
)
1486 tree unpadded_size
, unpadded_size_unit
;
1488 /* Now we want just byte and bit offsets, so set the offset alignment
1489 to be a byte and then normalize. */
1490 rli
->offset_align
= BITS_PER_UNIT
;
1491 normalize_rli (rli
);
1493 /* Determine the desired alignment. */
1494 #ifdef ROUND_TYPE_ALIGN
1495 TYPE_ALIGN (rli
->t
) = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
),
1498 TYPE_ALIGN (rli
->t
) = MAX (TYPE_ALIGN (rli
->t
), rli
->record_align
);
1501 /* Compute the size so far. Be sure to allow for extra bits in the
1502 size in bytes. We have guaranteed above that it will be no more
1503 than a single byte. */
1504 unpadded_size
= rli_size_so_far (rli
);
1505 unpadded_size_unit
= rli_size_unit_so_far (rli
);
1506 if (! integer_zerop (rli
->bitpos
))
1508 = size_binop (PLUS_EXPR
, unpadded_size_unit
, size_one_node
);
1510 /* Round the size up to be a multiple of the required alignment. */
1511 TYPE_SIZE (rli
->t
) = round_up (unpadded_size
, TYPE_ALIGN (rli
->t
));
1512 TYPE_SIZE_UNIT (rli
->t
)
1513 = round_up (unpadded_size_unit
, TYPE_ALIGN_UNIT (rli
->t
));
1515 if (TREE_CONSTANT (unpadded_size
)
1516 && simple_cst_equal (unpadded_size
, TYPE_SIZE (rli
->t
)) == 0
1517 && input_location
!= BUILTINS_LOCATION
)
1518 warning (OPT_Wpadded
, "padding struct size to alignment boundary");
1520 if (warn_packed
&& TREE_CODE (rli
->t
) == RECORD_TYPE
1521 && TYPE_PACKED (rli
->t
) && ! rli
->packed_maybe_necessary
1522 && TREE_CONSTANT (unpadded_size
))
1526 #ifdef ROUND_TYPE_ALIGN
1528 = ROUND_TYPE_ALIGN (rli
->t
, TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1530 rli
->unpacked_align
= MAX (TYPE_ALIGN (rli
->t
), rli
->unpacked_align
);
1533 unpacked_size
= round_up (TYPE_SIZE (rli
->t
), rli
->unpacked_align
);
1534 if (simple_cst_equal (unpacked_size
, TYPE_SIZE (rli
->t
)))
1536 if (TYPE_NAME (rli
->t
))
1540 if (TREE_CODE (TYPE_NAME (rli
->t
)) == IDENTIFIER_NODE
)
1541 name
= TYPE_NAME (rli
->t
);
1543 name
= DECL_NAME (TYPE_NAME (rli
->t
));
1545 if (STRICT_ALIGNMENT
)
1546 warning (OPT_Wpacked
, "packed attribute causes inefficient "
1547 "alignment for %qE", name
);
1549 warning (OPT_Wpacked
,
1550 "packed attribute is unnecessary for %qE", name
);
1554 if (STRICT_ALIGNMENT
)
1555 warning (OPT_Wpacked
,
1556 "packed attribute causes inefficient alignment");
1558 warning (OPT_Wpacked
, "packed attribute is unnecessary");
1564 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1567 compute_record_mode (tree type
)
1570 enum machine_mode mode
= VOIDmode
;
1572 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1573 However, if possible, we use a mode that fits in a register
1574 instead, in order to allow for better optimization down the
1576 SET_TYPE_MODE (type
, BLKmode
);
1578 if (! host_integerp (TYPE_SIZE (type
), 1))
1581 /* A record which has any BLKmode members must itself be
1582 BLKmode; it can't go in a register. Unless the member is
1583 BLKmode only because it isn't aligned. */
1584 for (field
= TYPE_FIELDS (type
); field
; field
= DECL_CHAIN (field
))
1586 if (TREE_CODE (field
) != FIELD_DECL
)
1589 if (TREE_CODE (TREE_TYPE (field
)) == ERROR_MARK
1590 || (TYPE_MODE (TREE_TYPE (field
)) == BLKmode
1591 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field
))
1592 && !(TYPE_SIZE (TREE_TYPE (field
)) != 0
1593 && integer_zerop (TYPE_SIZE (TREE_TYPE (field
)))))
1594 || ! host_integerp (bit_position (field
), 1)
1595 || DECL_SIZE (field
) == 0
1596 || ! host_integerp (DECL_SIZE (field
), 1))
1599 /* If this field is the whole struct, remember its mode so
1600 that, say, we can put a double in a class into a DF
1601 register instead of forcing it to live in the stack. */
1602 if (simple_cst_equal (TYPE_SIZE (type
), DECL_SIZE (field
)))
1603 mode
= DECL_MODE (field
);
1605 #ifdef MEMBER_TYPE_FORCES_BLK
1606 /* With some targets, eg. c4x, it is sub-optimal
1607 to access an aligned BLKmode structure as a scalar. */
1609 if (MEMBER_TYPE_FORCES_BLK (field
, mode
))
1611 #endif /* MEMBER_TYPE_FORCES_BLK */
1614 /* If we only have one real field; use its mode if that mode's size
1615 matches the type's size. This only applies to RECORD_TYPE. This
1616 does not apply to unions. */
1617 if (TREE_CODE (type
) == RECORD_TYPE
&& mode
!= VOIDmode
1618 && host_integerp (TYPE_SIZE (type
), 1)
1619 && GET_MODE_BITSIZE (mode
) == TREE_INT_CST_LOW (TYPE_SIZE (type
)))
1620 SET_TYPE_MODE (type
, mode
);
1622 SET_TYPE_MODE (type
, mode_for_size_tree (TYPE_SIZE (type
), MODE_INT
, 1));
1624 /* If structure's known alignment is less than what the scalar
1625 mode would need, and it matters, then stick with BLKmode. */
1626 if (TYPE_MODE (type
) != BLKmode
1628 && ! (TYPE_ALIGN (type
) >= BIGGEST_ALIGNMENT
1629 || TYPE_ALIGN (type
) >= GET_MODE_ALIGNMENT (TYPE_MODE (type
))))
1631 /* If this is the only reason this type is BLKmode, then
1632 don't force containing types to be BLKmode. */
1633 TYPE_NO_FORCE_BLK (type
) = 1;
1634 SET_TYPE_MODE (type
, BLKmode
);
1638 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1642 finalize_type_size (tree type
)
1644 /* Normally, use the alignment corresponding to the mode chosen.
1645 However, where strict alignment is not required, avoid
1646 over-aligning structures, since most compilers do not do this
1649 if (TYPE_MODE (type
) != BLKmode
&& TYPE_MODE (type
) != VOIDmode
1650 && (STRICT_ALIGNMENT
1651 || (TREE_CODE (type
) != RECORD_TYPE
&& TREE_CODE (type
) != UNION_TYPE
1652 && TREE_CODE (type
) != QUAL_UNION_TYPE
1653 && TREE_CODE (type
) != ARRAY_TYPE
)))
1655 unsigned mode_align
= GET_MODE_ALIGNMENT (TYPE_MODE (type
));
1657 /* Don't override a larger alignment requirement coming from a user
1658 alignment of one of the fields. */
1659 if (mode_align
>= TYPE_ALIGN (type
))
1661 TYPE_ALIGN (type
) = mode_align
;
1662 TYPE_USER_ALIGN (type
) = 0;
1666 /* Do machine-dependent extra alignment. */
1667 #ifdef ROUND_TYPE_ALIGN
1669 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (type
), BITS_PER_UNIT
);
1672 /* If we failed to find a simple way to calculate the unit size
1673 of the type, find it by division. */
1674 if (TYPE_SIZE_UNIT (type
) == 0 && TYPE_SIZE (type
) != 0)
1675 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1676 result will fit in sizetype. We will get more efficient code using
1677 sizetype, so we force a conversion. */
1678 TYPE_SIZE_UNIT (type
)
1679 = fold_convert (sizetype
,
1680 size_binop (FLOOR_DIV_EXPR
, TYPE_SIZE (type
),
1681 bitsize_unit_node
));
1683 if (TYPE_SIZE (type
) != 0)
1685 TYPE_SIZE (type
) = round_up (TYPE_SIZE (type
), TYPE_ALIGN (type
));
1686 TYPE_SIZE_UNIT (type
)
1687 = round_up (TYPE_SIZE_UNIT (type
), TYPE_ALIGN_UNIT (type
));
1690 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1691 if (TYPE_SIZE (type
) != 0 && TREE_CODE (TYPE_SIZE (type
)) != INTEGER_CST
)
1692 TYPE_SIZE (type
) = variable_size (TYPE_SIZE (type
));
1693 if (TYPE_SIZE_UNIT (type
) != 0
1694 && TREE_CODE (TYPE_SIZE_UNIT (type
)) != INTEGER_CST
)
1695 TYPE_SIZE_UNIT (type
) = variable_size (TYPE_SIZE_UNIT (type
));
1697 /* Also layout any other variants of the type. */
1698 if (TYPE_NEXT_VARIANT (type
)
1699 || type
!= TYPE_MAIN_VARIANT (type
))
1702 /* Record layout info of this variant. */
1703 tree size
= TYPE_SIZE (type
);
1704 tree size_unit
= TYPE_SIZE_UNIT (type
);
1705 unsigned int align
= TYPE_ALIGN (type
);
1706 unsigned int user_align
= TYPE_USER_ALIGN (type
);
1707 enum machine_mode mode
= TYPE_MODE (type
);
1709 /* Copy it into all variants. */
1710 for (variant
= TYPE_MAIN_VARIANT (type
);
1712 variant
= TYPE_NEXT_VARIANT (variant
))
1714 TYPE_SIZE (variant
) = size
;
1715 TYPE_SIZE_UNIT (variant
) = size_unit
;
1716 TYPE_ALIGN (variant
) = align
;
1717 TYPE_USER_ALIGN (variant
) = user_align
;
1718 SET_TYPE_MODE (variant
, mode
);
1723 /* Do all of the work required to layout the type indicated by RLI,
1724 once the fields have been laid out. This function will call `free'
1725 for RLI, unless FREE_P is false. Passing a value other than false
1726 for FREE_P is bad practice; this option only exists to support the
1730 finish_record_layout (record_layout_info rli
, int free_p
)
1734 /* Compute the final size. */
1735 finalize_record_size (rli
);
1737 /* Compute the TYPE_MODE for the record. */
1738 compute_record_mode (rli
->t
);
1740 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1741 finalize_type_size (rli
->t
);
1743 /* Propagate TYPE_PACKED to variants. With C++ templates,
1744 handle_packed_attribute is too early to do this. */
1745 for (variant
= TYPE_NEXT_VARIANT (rli
->t
); variant
;
1746 variant
= TYPE_NEXT_VARIANT (variant
))
1747 TYPE_PACKED (variant
) = TYPE_PACKED (rli
->t
);
1749 /* Lay out any static members. This is done now because their type
1750 may use the record's type. */
1751 while (!VEC_empty (tree
, rli
->pending_statics
))
1752 layout_decl (VEC_pop (tree
, rli
->pending_statics
), 0);
1757 VEC_free (tree
, gc
, rli
->pending_statics
);
1763 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1764 NAME, its fields are chained in reverse on FIELDS.
1766 If ALIGN_TYPE is non-null, it is given the same alignment as
1770 finish_builtin_struct (tree type
, const char *name
, tree fields
,
1775 for (tail
= NULL_TREE
; fields
; tail
= fields
, fields
= next
)
1777 DECL_FIELD_CONTEXT (fields
) = type
;
1778 next
= DECL_CHAIN (fields
);
1779 DECL_CHAIN (fields
) = tail
;
1781 TYPE_FIELDS (type
) = tail
;
1785 TYPE_ALIGN (type
) = TYPE_ALIGN (align_type
);
1786 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (align_type
);
1790 #if 0 /* not yet, should get fixed properly later */
1791 TYPE_NAME (type
) = make_type_decl (get_identifier (name
), type
);
1793 TYPE_NAME (type
) = build_decl (BUILTINS_LOCATION
,
1794 TYPE_DECL
, get_identifier (name
), type
);
1796 TYPE_STUB_DECL (type
) = TYPE_NAME (type
);
1797 layout_decl (TYPE_NAME (type
), 0);
1800 /* Calculate the mode, size, and alignment for TYPE.
1801 For an array type, calculate the element separation as well.
1802 Record TYPE on the chain of permanent or temporary types
1803 so that dbxout will find out about it.
1805 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1806 layout_type does nothing on such a type.
1808 If the type is incomplete, its TYPE_SIZE remains zero. */
1811 layout_type (tree type
)
1815 if (type
== error_mark_node
)
1818 /* Do nothing if type has been laid out before. */
1819 if (TYPE_SIZE (type
))
1822 switch (TREE_CODE (type
))
1825 /* This kind of type is the responsibility
1826 of the language-specific code. */
1829 case BOOLEAN_TYPE
: /* Used for Java, Pascal, and Chill. */
1830 if (TYPE_PRECISION (type
) == 0)
1831 TYPE_PRECISION (type
) = 1; /* default to one byte/boolean. */
1833 /* ... fall through ... */
1837 if (TREE_CODE (TYPE_MIN_VALUE (type
)) == INTEGER_CST
1838 && tree_int_cst_sgn (TYPE_MIN_VALUE (type
)) >= 0)
1839 TYPE_UNSIGNED (type
) = 1;
1841 SET_TYPE_MODE (type
,
1842 smallest_mode_for_size (TYPE_PRECISION (type
), MODE_INT
));
1843 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1844 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1848 SET_TYPE_MODE (type
,
1849 mode_for_size (TYPE_PRECISION (type
), MODE_FLOAT
, 0));
1850 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1851 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1854 case FIXED_POINT_TYPE
:
1855 /* TYPE_MODE (type) has been set already. */
1856 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1857 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1861 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1862 SET_TYPE_MODE (type
,
1863 mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type
)),
1864 (TREE_CODE (TREE_TYPE (type
)) == REAL_TYPE
1865 ? MODE_COMPLEX_FLOAT
: MODE_COMPLEX_INT
),
1867 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type
)));
1868 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (TYPE_MODE (type
)));
1873 int nunits
= TYPE_VECTOR_SUBPARTS (type
);
1874 tree innertype
= TREE_TYPE (type
);
1876 gcc_assert (!(nunits
& (nunits
- 1)));
1878 /* Find an appropriate mode for the vector type. */
1879 if (TYPE_MODE (type
) == VOIDmode
)
1880 SET_TYPE_MODE (type
,
1881 mode_for_vector (TYPE_MODE (innertype
), nunits
));
1883 TYPE_SATURATING (type
) = TYPE_SATURATING (TREE_TYPE (type
));
1884 TYPE_UNSIGNED (type
) = TYPE_UNSIGNED (TREE_TYPE (type
));
1885 TYPE_SIZE_UNIT (type
) = int_const_binop (MULT_EXPR
,
1886 TYPE_SIZE_UNIT (innertype
),
1888 TYPE_SIZE (type
) = int_const_binop (MULT_EXPR
, TYPE_SIZE (innertype
),
1889 bitsize_int (nunits
));
1891 /* Always naturally align vectors. This prevents ABI changes
1892 depending on whether or not native vector modes are supported. */
1893 TYPE_ALIGN (type
) = tree_low_cst (TYPE_SIZE (type
), 0);
1898 /* This is an incomplete type and so doesn't have a size. */
1899 TYPE_ALIGN (type
) = 1;
1900 TYPE_USER_ALIGN (type
) = 0;
1901 SET_TYPE_MODE (type
, VOIDmode
);
1905 TYPE_SIZE (type
) = bitsize_int (POINTER_SIZE
);
1906 TYPE_SIZE_UNIT (type
) = size_int (POINTER_SIZE
/ BITS_PER_UNIT
);
1907 /* A pointer might be MODE_PARTIAL_INT,
1908 but ptrdiff_t must be integral. */
1909 SET_TYPE_MODE (type
, mode_for_size (POINTER_SIZE
, MODE_INT
, 0));
1910 TYPE_PRECISION (type
) = POINTER_SIZE
;
1915 /* It's hard to see what the mode and size of a function ought to
1916 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1917 make it consistent with that. */
1918 SET_TYPE_MODE (type
, mode_for_size (FUNCTION_BOUNDARY
, MODE_INT
, 0));
1919 TYPE_SIZE (type
) = bitsize_int (FUNCTION_BOUNDARY
);
1920 TYPE_SIZE_UNIT (type
) = size_int (FUNCTION_BOUNDARY
/ BITS_PER_UNIT
);
1924 case REFERENCE_TYPE
:
1926 enum machine_mode mode
= TYPE_MODE (type
);
1927 if (TREE_CODE (type
) == REFERENCE_TYPE
&& reference_types_internal
)
1929 addr_space_t as
= TYPE_ADDR_SPACE (TREE_TYPE (type
));
1930 mode
= targetm
.addr_space
.address_mode (as
);
1933 TYPE_SIZE (type
) = bitsize_int (GET_MODE_BITSIZE (mode
));
1934 TYPE_SIZE_UNIT (type
) = size_int (GET_MODE_SIZE (mode
));
1935 TYPE_UNSIGNED (type
) = 1;
1936 TYPE_PRECISION (type
) = GET_MODE_BITSIZE (mode
);
1942 tree index
= TYPE_DOMAIN (type
);
1943 tree element
= TREE_TYPE (type
);
1945 build_pointer_type (element
);
1947 /* We need to know both bounds in order to compute the size. */
1948 if (index
&& TYPE_MAX_VALUE (index
) && TYPE_MIN_VALUE (index
)
1949 && TYPE_SIZE (element
))
1951 tree ub
= TYPE_MAX_VALUE (index
);
1952 tree lb
= TYPE_MIN_VALUE (index
);
1953 tree element_size
= TYPE_SIZE (element
);
1956 /* Make sure that an array of zero-sized element is zero-sized
1957 regardless of its extent. */
1958 if (integer_zerop (element_size
))
1959 length
= size_zero_node
;
1961 /* The computation should happen in the original type so
1962 that (possible) negative values are handled appropriately. */
1965 = fold_convert (sizetype
,
1966 fold_build2 (PLUS_EXPR
, TREE_TYPE (lb
),
1967 build_int_cst (TREE_TYPE (lb
), 1),
1968 fold_build2 (MINUS_EXPR
,
1972 TYPE_SIZE (type
) = size_binop (MULT_EXPR
, element_size
,
1973 fold_convert (bitsizetype
,
1976 /* If we know the size of the element, calculate the total size
1977 directly, rather than do some division thing below. This
1978 optimization helps Fortran assumed-size arrays (where the
1979 size of the array is determined at runtime) substantially. */
1980 if (TYPE_SIZE_UNIT (element
))
1981 TYPE_SIZE_UNIT (type
)
1982 = size_binop (MULT_EXPR
, TYPE_SIZE_UNIT (element
), length
);
1985 /* Now round the alignment and size,
1986 using machine-dependent criteria if any. */
1988 #ifdef ROUND_TYPE_ALIGN
1990 = ROUND_TYPE_ALIGN (type
, TYPE_ALIGN (element
), BITS_PER_UNIT
);
1992 TYPE_ALIGN (type
) = MAX (TYPE_ALIGN (element
), BITS_PER_UNIT
);
1994 TYPE_USER_ALIGN (type
) = TYPE_USER_ALIGN (element
);
1995 SET_TYPE_MODE (type
, BLKmode
);
1996 if (TYPE_SIZE (type
) != 0
1997 #ifdef MEMBER_TYPE_FORCES_BLK
1998 && ! MEMBER_TYPE_FORCES_BLK (type
, VOIDmode
)
2000 /* BLKmode elements force BLKmode aggregate;
2001 else extract/store fields may lose. */
2002 && (TYPE_MODE (TREE_TYPE (type
)) != BLKmode
2003 || TYPE_NO_FORCE_BLK (TREE_TYPE (type
))))
2005 SET_TYPE_MODE (type
, mode_for_array (TREE_TYPE (type
),
2007 if (TYPE_MODE (type
) != BLKmode
2008 && STRICT_ALIGNMENT
&& TYPE_ALIGN (type
) < BIGGEST_ALIGNMENT
2009 && TYPE_ALIGN (type
) < GET_MODE_ALIGNMENT (TYPE_MODE (type
)))
2011 TYPE_NO_FORCE_BLK (type
) = 1;
2012 SET_TYPE_MODE (type
, BLKmode
);
2015 /* When the element size is constant, check that it is at least as
2016 large as the element alignment. */
2017 if (TYPE_SIZE_UNIT (element
)
2018 && TREE_CODE (TYPE_SIZE_UNIT (element
)) == INTEGER_CST
2019 /* If TYPE_SIZE_UNIT overflowed, then it is certainly larger than
2021 && !TREE_OVERFLOW (TYPE_SIZE_UNIT (element
))
2022 && !integer_zerop (TYPE_SIZE_UNIT (element
))
2023 && compare_tree_int (TYPE_SIZE_UNIT (element
),
2024 TYPE_ALIGN_UNIT (element
)) < 0)
2025 error ("alignment of array elements is greater than element size");
2031 case QUAL_UNION_TYPE
:
2034 record_layout_info rli
;
2036 /* Initialize the layout information. */
2037 rli
= start_record_layout (type
);
2039 /* If this is a QUAL_UNION_TYPE, we want to process the fields
2040 in the reverse order in building the COND_EXPR that denotes
2041 its size. We reverse them again later. */
2042 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
2043 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
2045 /* Place all the fields. */
2046 for (field
= TYPE_FIELDS (type
); field
; field
= DECL_CHAIN (field
))
2047 place_field (rli
, field
);
2049 if (TREE_CODE (type
) == QUAL_UNION_TYPE
)
2050 TYPE_FIELDS (type
) = nreverse (TYPE_FIELDS (type
));
2052 /* Finish laying out the record. */
2053 finish_record_layout (rli
, /*free_p=*/true);
2061 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
2062 records and unions, finish_record_layout already called this
2064 if (TREE_CODE (type
) != RECORD_TYPE
2065 && TREE_CODE (type
) != UNION_TYPE
2066 && TREE_CODE (type
) != QUAL_UNION_TYPE
)
2067 finalize_type_size (type
);
2069 /* We should never see alias sets on incomplete aggregates. And we
2070 should not call layout_type on not incomplete aggregates. */
2071 if (AGGREGATE_TYPE_P (type
))
2072 gcc_assert (!TYPE_ALIAS_SET_KNOWN_P (type
));
2075 /* Vector types need to re-check the target flags each time we report
2076 the machine mode. We need to do this because attribute target can
2077 change the result of vector_mode_supported_p and have_regs_of_mode
2078 on a per-function basis. Thus the TYPE_MODE of a VECTOR_TYPE can
2079 change on a per-function basis. */
2080 /* ??? Possibly a better solution is to run through all the types
2081 referenced by a function and re-compute the TYPE_MODE once, rather
2082 than make the TYPE_MODE macro call a function. */
2085 vector_type_mode (const_tree t
)
2087 enum machine_mode mode
;
2089 gcc_assert (TREE_CODE (t
) == VECTOR_TYPE
);
2091 mode
= t
->type_common
.mode
;
2092 if (VECTOR_MODE_P (mode
)
2093 && (!targetm
.vector_mode_supported_p (mode
)
2094 || !have_regs_of_mode
[mode
]))
2096 enum machine_mode innermode
= TREE_TYPE (t
)->type_common
.mode
;
2098 /* For integers, try mapping it to a same-sized scalar mode. */
2099 if (GET_MODE_CLASS (innermode
) == MODE_INT
)
2101 mode
= mode_for_size (TYPE_VECTOR_SUBPARTS (t
)
2102 * GET_MODE_BITSIZE (innermode
), MODE_INT
, 0);
2104 if (mode
!= VOIDmode
&& have_regs_of_mode
[mode
])
2114 /* Create and return a type for signed integers of PRECISION bits. */
2117 make_signed_type (int precision
)
2119 tree type
= make_node (INTEGER_TYPE
);
2121 TYPE_PRECISION (type
) = precision
;
2123 fixup_signed_type (type
);
2127 /* Create and return a type for unsigned integers of PRECISION bits. */
2130 make_unsigned_type (int precision
)
2132 tree type
= make_node (INTEGER_TYPE
);
2134 TYPE_PRECISION (type
) = precision
;
2136 fixup_unsigned_type (type
);
2140 /* Create and return a type for fract of PRECISION bits, UNSIGNEDP,
2144 make_fract_type (int precision
, int unsignedp
, int satp
)
2146 tree type
= make_node (FIXED_POINT_TYPE
);
2148 TYPE_PRECISION (type
) = precision
;
2151 TYPE_SATURATING (type
) = 1;
2153 /* Lay out the type: set its alignment, size, etc. */
2156 TYPE_UNSIGNED (type
) = 1;
2157 SET_TYPE_MODE (type
, mode_for_size (precision
, MODE_UFRACT
, 0));
2160 SET_TYPE_MODE (type
, mode_for_size (precision
, MODE_FRACT
, 0));
2166 /* Create and return a type for accum of PRECISION bits, UNSIGNEDP,
2170 make_accum_type (int precision
, int unsignedp
, int satp
)
2172 tree type
= make_node (FIXED_POINT_TYPE
);
2174 TYPE_PRECISION (type
) = precision
;
2177 TYPE_SATURATING (type
) = 1;
2179 /* Lay out the type: set its alignment, size, etc. */
2182 TYPE_UNSIGNED (type
) = 1;
2183 SET_TYPE_MODE (type
, mode_for_size (precision
, MODE_UACCUM
, 0));
2186 SET_TYPE_MODE (type
, mode_for_size (precision
, MODE_ACCUM
, 0));
2192 /* Initialize sizetypes so layout_type can use them. */
2195 initialize_sizetypes (void)
2197 int precision
, bprecision
;
2199 /* Get sizetypes precision from the SIZE_TYPE target macro. */
2200 if (strcmp (SIZE_TYPE
, "unsigned int") == 0)
2201 precision
= INT_TYPE_SIZE
;
2202 else if (strcmp (SIZE_TYPE
, "long unsigned int") == 0)
2203 precision
= LONG_TYPE_SIZE
;
2204 else if (strcmp (SIZE_TYPE
, "long long unsigned int") == 0)
2205 precision
= LONG_LONG_TYPE_SIZE
;
2210 = MIN (precision
+ BITS_PER_UNIT_LOG
+ 1, MAX_FIXED_MODE_SIZE
);
2212 = GET_MODE_PRECISION (smallest_mode_for_size (bprecision
, MODE_INT
));
2213 if (bprecision
> HOST_BITS_PER_WIDE_INT
* 2)
2214 bprecision
= HOST_BITS_PER_WIDE_INT
* 2;
2216 /* Create stubs for sizetype and bitsizetype so we can create constants. */
2217 sizetype
= make_node (INTEGER_TYPE
);
2218 /* ??? We can't set a name for sizetype because it appears in C diagnostics
2219 and pp_c_type_specifier doesn't deal with IDENTIFIER_NODE TYPE_NAMEs. */
2220 TYPE_PRECISION (sizetype
) = precision
;
2221 TYPE_UNSIGNED (sizetype
) = 1;
2222 TYPE_IS_SIZETYPE (sizetype
) = 1;
2223 bitsizetype
= make_node (INTEGER_TYPE
);
2224 TYPE_NAME (bitsizetype
) = get_identifier ("bitsizetype");
2225 TYPE_PRECISION (bitsizetype
) = bprecision
;
2226 TYPE_UNSIGNED (bitsizetype
) = 1;
2227 TYPE_IS_SIZETYPE (bitsizetype
) = 1;
2229 /* Now layout both types manually. */
2230 SET_TYPE_MODE (sizetype
, smallest_mode_for_size (precision
, MODE_INT
));
2231 TYPE_ALIGN (sizetype
) = GET_MODE_ALIGNMENT (TYPE_MODE (sizetype
));
2232 TYPE_SIZE (sizetype
) = bitsize_int (precision
);
2233 TYPE_SIZE_UNIT (sizetype
) = size_int (GET_MODE_SIZE (TYPE_MODE (sizetype
)));
2234 set_min_and_max_values_for_integral_type (sizetype
, precision
,
2235 /*is_unsigned=*/true);
2236 /* sizetype is unsigned but we need to fix TYPE_MAX_VALUE so that it is
2237 sign-extended in a way consistent with force_fit_type. */
2238 TYPE_MAX_VALUE (sizetype
)
2239 = double_int_to_tree (sizetype
,
2240 tree_to_double_int (TYPE_MAX_VALUE (sizetype
)));
2242 SET_TYPE_MODE (bitsizetype
, smallest_mode_for_size (bprecision
, MODE_INT
));
2243 TYPE_ALIGN (bitsizetype
) = GET_MODE_ALIGNMENT (TYPE_MODE (bitsizetype
));
2244 TYPE_SIZE (bitsizetype
) = bitsize_int (bprecision
);
2245 TYPE_SIZE_UNIT (bitsizetype
)
2246 = size_int (GET_MODE_SIZE (TYPE_MODE (bitsizetype
)));
2247 set_min_and_max_values_for_integral_type (bitsizetype
, bprecision
,
2248 /*is_unsigned=*/true);
2249 /* ??? TYPE_MAX_VALUE is not properly sign-extended. */
2251 /* Create the signed variants of *sizetype. */
2252 ssizetype
= make_signed_type (TYPE_PRECISION (sizetype
));
2253 TYPE_IS_SIZETYPE (ssizetype
) = 1;
2254 sbitsizetype
= make_signed_type (TYPE_PRECISION (bitsizetype
));
2255 TYPE_IS_SIZETYPE (sbitsizetype
) = 1;
2258 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE
2259 or BOOLEAN_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
2260 for TYPE, based on the PRECISION and whether or not the TYPE
2261 IS_UNSIGNED. PRECISION need not correspond to a width supported
2262 natively by the hardware; for example, on a machine with 8-bit,
2263 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
2267 set_min_and_max_values_for_integral_type (tree type
,
2276 min_value
= build_int_cst (type
, 0);
2278 = build_int_cst_wide (type
, precision
- HOST_BITS_PER_WIDE_INT
>= 0
2280 : ((HOST_WIDE_INT
) 1 << precision
) - 1,
2281 precision
- HOST_BITS_PER_WIDE_INT
> 0
2282 ? ((unsigned HOST_WIDE_INT
) ~0
2283 >> (HOST_BITS_PER_WIDE_INT
2284 - (precision
- HOST_BITS_PER_WIDE_INT
)))
2290 = build_int_cst_wide (type
,
2291 (precision
- HOST_BITS_PER_WIDE_INT
> 0
2293 : (HOST_WIDE_INT
) (-1) << (precision
- 1)),
2294 (((HOST_WIDE_INT
) (-1)
2295 << (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
2296 ? precision
- HOST_BITS_PER_WIDE_INT
- 1
2299 = build_int_cst_wide (type
,
2300 (precision
- HOST_BITS_PER_WIDE_INT
> 0
2302 : ((HOST_WIDE_INT
) 1 << (precision
- 1)) - 1),
2303 (precision
- HOST_BITS_PER_WIDE_INT
- 1 > 0
2304 ? (((HOST_WIDE_INT
) 1
2305 << (precision
- HOST_BITS_PER_WIDE_INT
- 1))) - 1
2309 TYPE_MIN_VALUE (type
) = min_value
;
2310 TYPE_MAX_VALUE (type
) = max_value
;
2313 /* Set the extreme values of TYPE based on its precision in bits,
2314 then lay it out. Used when make_signed_type won't do
2315 because the tree code is not INTEGER_TYPE.
2316 E.g. for Pascal, when the -fsigned-char option is given. */
2319 fixup_signed_type (tree type
)
2321 int precision
= TYPE_PRECISION (type
);
2323 /* We can not represent properly constants greater then
2324 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2325 as they are used by i386 vector extensions and friends. */
2326 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2327 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2329 set_min_and_max_values_for_integral_type (type
, precision
,
2330 /*is_unsigned=*/false);
2332 /* Lay out the type: set its alignment, size, etc. */
2336 /* Set the extreme values of TYPE based on its precision in bits,
2337 then lay it out. This is used both in `make_unsigned_type'
2338 and for enumeral types. */
2341 fixup_unsigned_type (tree type
)
2343 int precision
= TYPE_PRECISION (type
);
2345 /* We can not represent properly constants greater then
2346 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2347 as they are used by i386 vector extensions and friends. */
2348 if (precision
> HOST_BITS_PER_WIDE_INT
* 2)
2349 precision
= HOST_BITS_PER_WIDE_INT
* 2;
2351 TYPE_UNSIGNED (type
) = 1;
2353 set_min_and_max_values_for_integral_type (type
, precision
,
2354 /*is_unsigned=*/true);
2356 /* Lay out the type: set its alignment, size, etc. */
2360 /* Find the best machine mode to use when referencing a bit field of length
2361 BITSIZE bits starting at BITPOS.
2363 The underlying object is known to be aligned to a boundary of ALIGN bits.
2364 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2365 larger than LARGEST_MODE (usually SImode).
2367 If no mode meets all these conditions, we return VOIDmode.
2369 If VOLATILEP is false and SLOW_BYTE_ACCESS is false, we return the
2370 smallest mode meeting these conditions.
2372 If VOLATILEP is false and SLOW_BYTE_ACCESS is true, we return the
2373 largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2376 If VOLATILEP is true the narrow_volatile_bitfields target hook is used to
2377 decide which of the above modes should be used. */
2380 get_best_mode (int bitsize
, int bitpos
, unsigned int align
,
2381 enum machine_mode largest_mode
, int volatilep
)
2383 enum machine_mode mode
;
2384 unsigned int unit
= 0;
2386 /* Find the narrowest integer mode that contains the bit field. */
2387 for (mode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); mode
!= VOIDmode
;
2388 mode
= GET_MODE_WIDER_MODE (mode
))
2390 unit
= GET_MODE_BITSIZE (mode
);
2391 if ((bitpos
% unit
) + bitsize
<= unit
)
2395 if (mode
== VOIDmode
2396 /* It is tempting to omit the following line
2397 if STRICT_ALIGNMENT is true.
2398 But that is incorrect, since if the bitfield uses part of 3 bytes
2399 and we use a 4-byte mode, we could get a spurious segv
2400 if the extra 4th byte is past the end of memory.
2401 (Though at least one Unix compiler ignores this problem:
2402 that on the Sequent 386 machine. */
2403 || MIN (unit
, BIGGEST_ALIGNMENT
) > align
2404 || (largest_mode
!= VOIDmode
&& unit
> GET_MODE_BITSIZE (largest_mode
)))
2407 if ((SLOW_BYTE_ACCESS
&& ! volatilep
)
2408 || (volatilep
&& !targetm
.narrow_volatile_bitfield ()))
2410 enum machine_mode wide_mode
= VOIDmode
, tmode
;
2412 for (tmode
= GET_CLASS_NARROWEST_MODE (MODE_INT
); tmode
!= VOIDmode
;
2413 tmode
= GET_MODE_WIDER_MODE (tmode
))
2415 unit
= GET_MODE_BITSIZE (tmode
);
2416 if (bitpos
/ unit
== (bitpos
+ bitsize
- 1) / unit
2417 && unit
<= BITS_PER_WORD
2418 && unit
<= MIN (align
, BIGGEST_ALIGNMENT
)
2419 && (largest_mode
== VOIDmode
2420 || unit
<= GET_MODE_BITSIZE (largest_mode
)))
2424 if (wide_mode
!= VOIDmode
)
2431 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2432 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2435 get_mode_bounds (enum machine_mode mode
, int sign
,
2436 enum machine_mode target_mode
,
2437 rtx
*mmin
, rtx
*mmax
)
2439 unsigned size
= GET_MODE_BITSIZE (mode
);
2440 unsigned HOST_WIDE_INT min_val
, max_val
;
2442 gcc_assert (size
<= HOST_BITS_PER_WIDE_INT
);
2446 min_val
= -((unsigned HOST_WIDE_INT
) 1 << (size
- 1));
2447 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1)) - 1;
2452 max_val
= ((unsigned HOST_WIDE_INT
) 1 << (size
- 1) << 1) - 1;
2455 *mmin
= gen_int_mode (min_val
, target_mode
);
2456 *mmax
= gen_int_mode (max_val
, target_mode
);
2459 #include "gt-stor-layout.h"