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 /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
70 static GTY(()) VEC(tree,gc) *pending_sizes;
72 /* Show that REFERENCE_TYPES are internal and should use address_mode.
73 Called only by front end. */
76 internal_reference_types (void)
78 reference_types_internal = 1;
81 /* Get a VEC of all the objects put on the pending sizes list. */
84 get_pending_sizes (void)
86 VEC(tree,gc) *chain = pending_sizes;
92 /* Add EXPR to the pending sizes list. */
95 put_pending_size (tree expr)
97 /* Strip any simple arithmetic from EXPR to see if it has an underlying
99 expr = skip_simple_arithmetic (expr);
101 if (TREE_CODE (expr) == SAVE_EXPR)
102 VEC_safe_push (tree, gc, pending_sizes, expr);
105 /* Put a chain of objects into the pending sizes list, which must be
109 put_pending_sizes (VEC(tree,gc) *chain)
111 gcc_assert (!pending_sizes);
112 pending_sizes = chain;
115 /* Given a size SIZE that may not be a constant, return a SAVE_EXPR
116 to serve as the actual size-expression for a type or decl. */
119 variable_size (tree size)
124 if (TREE_CONSTANT (size))
127 /* If the size is self-referential, we can't make a SAVE_EXPR (see
128 save_expr for the rationale). But we can do something else. */
129 if (CONTAINS_PLACEHOLDER_P (size))
130 return self_referential_size (size);
132 /* If the language-processor is to take responsibility for variable-sized
133 items (e.g., languages which have elaboration procedures like Ada),
134 just return SIZE unchanged. */
135 if (lang_hooks.decls.global_bindings_p () < 0)
138 size = save_expr (size);
140 /* If an array with a variable number of elements is declared, and
141 the elements require destruction, we will emit a cleanup for the
142 array. That cleanup is run both on normal exit from the block
143 and in the exception-handler for the block. Normally, when code
144 is used in both ordinary code and in an exception handler it is
145 `unsaved', i.e., all SAVE_EXPRs are recalculated. However, we do
146 not wish to do that here; the array-size is the same in both
148 save = skip_simple_arithmetic (size);
150 if (cfun && cfun->dont_save_pending_sizes_p)
151 /* The front-end doesn't want us to keep a list of the expressions
152 that determine sizes for variable size objects. Trust it. */
155 if (lang_hooks.decls.global_bindings_p ())
157 if (TREE_CONSTANT (size))
158 error ("type size can%'t be explicitly evaluated");
160 error ("variable-size type declared outside of any function");
162 return size_one_node;
165 put_pending_size (save);
170 /* An array of functions used for self-referential size computation. */
171 static GTY(()) VEC (tree, gc) *size_functions;
173 /* Look inside EXPR into simple arithmetic operations involving constants.
174 Return the outermost non-arithmetic or non-constant node. */
177 skip_simple_constant_arithmetic (tree expr)
181 if (UNARY_CLASS_P (expr))
182 expr = TREE_OPERAND (expr, 0);
183 else if (BINARY_CLASS_P (expr))
185 if (TREE_CONSTANT (TREE_OPERAND (expr, 1)))
186 expr = TREE_OPERAND (expr, 0);
187 else if (TREE_CONSTANT (TREE_OPERAND (expr, 0)))
188 expr = TREE_OPERAND (expr, 1);
199 /* Similar to copy_tree_r but do not copy component references involving
200 PLACEHOLDER_EXPRs. These nodes are spotted in find_placeholder_in_expr
201 and substituted in substitute_in_expr. */
204 copy_self_referential_tree_r (tree *tp, int *walk_subtrees, void *data)
206 enum tree_code code = TREE_CODE (*tp);
208 /* Stop at types, decls, constants like copy_tree_r. */
209 if (TREE_CODE_CLASS (code) == tcc_type
210 || TREE_CODE_CLASS (code) == tcc_declaration
211 || TREE_CODE_CLASS (code) == tcc_constant)
217 /* This is the pattern built in ada/make_aligning_type. */
218 else if (code == ADDR_EXPR
219 && TREE_CODE (TREE_OPERAND (*tp, 0)) == PLACEHOLDER_EXPR)
225 /* Default case: the component reference. */
226 else if (code == COMPONENT_REF)
229 for (inner = TREE_OPERAND (*tp, 0);
230 REFERENCE_CLASS_P (inner);
231 inner = TREE_OPERAND (inner, 0))
234 if (TREE_CODE (inner) == PLACEHOLDER_EXPR)
241 /* We're not supposed to have them in self-referential size trees
242 because we wouldn't properly control when they are evaluated.
243 However, not creating superfluous SAVE_EXPRs requires accurate
244 tracking of readonly-ness all the way down to here, which we
245 cannot always guarantee in practice. So punt in this case. */
246 else if (code == SAVE_EXPR)
247 return error_mark_node;
249 return copy_tree_r (tp, walk_subtrees, data);
252 /* Given a SIZE expression that is self-referential, return an equivalent
253 expression to serve as the actual size expression for a type. */
256 self_referential_size (tree size)
258 static unsigned HOST_WIDE_INT fnno = 0;
259 VEC (tree, heap) *self_refs = NULL;
260 tree param_type_list = NULL, param_decl_list = NULL;
261 tree t, ref, return_type, fntype, fnname, fndecl;
264 VEC(tree,gc) *args = NULL;
266 /* Do not factor out simple operations. */
267 t = skip_simple_constant_arithmetic (size);
268 if (TREE_CODE (t) == CALL_EXPR)
271 /* Collect the list of self-references in the expression. */
272 find_placeholder_in_expr (size, &self_refs);
273 gcc_assert (VEC_length (tree, self_refs) > 0);
275 /* Obtain a private copy of the expression. */
277 if (walk_tree (&t, copy_self_referential_tree_r, NULL, NULL) != NULL_TREE)
281 /* Build the parameter and argument lists in parallel; also
282 substitute the former for the latter in the expression. */
283 args = VEC_alloc (tree, gc, VEC_length (tree, self_refs));
284 FOR_EACH_VEC_ELT (tree, self_refs, i, ref)
286 tree subst, param_name, param_type, param_decl;
290 /* We shouldn't have true variables here. */
291 gcc_assert (TREE_READONLY (ref));
294 /* This is the pattern built in ada/make_aligning_type. */
295 else if (TREE_CODE (ref) == ADDR_EXPR)
297 /* Default case: the component reference. */
299 subst = TREE_OPERAND (ref, 1);
301 sprintf (buf, "p%d", i);
302 param_name = get_identifier (buf);
303 param_type = TREE_TYPE (ref);
305 = build_decl (input_location, PARM_DECL, param_name, param_type);
306 if (targetm.calls.promote_prototypes (NULL_TREE)
307 && INTEGRAL_TYPE_P (param_type)
308 && TYPE_PRECISION (param_type) < TYPE_PRECISION (integer_type_node))
309 DECL_ARG_TYPE (param_decl) = integer_type_node;
311 DECL_ARG_TYPE (param_decl) = param_type;
312 DECL_ARTIFICIAL (param_decl) = 1;
313 TREE_READONLY (param_decl) = 1;
315 size = substitute_in_expr (size, subst, param_decl);
317 param_type_list = tree_cons (NULL_TREE, param_type, param_type_list);
318 param_decl_list = chainon (param_decl, param_decl_list);
319 VEC_quick_push (tree, args, ref);
322 VEC_free (tree, heap, self_refs);
324 /* Append 'void' to indicate that the number of parameters is fixed. */
325 param_type_list = tree_cons (NULL_TREE, void_type_node, param_type_list);
327 /* The 3 lists have been created in reverse order. */
328 param_type_list = nreverse (param_type_list);
329 param_decl_list = nreverse (param_decl_list);
331 /* Build the function type. */
332 return_type = TREE_TYPE (size);
333 fntype = build_function_type (return_type, param_type_list);
335 /* Build the function declaration. */
336 sprintf (buf, "SZ"HOST_WIDE_INT_PRINT_UNSIGNED, fnno++);
337 fnname = get_file_function_name (buf);
338 fndecl = build_decl (input_location, FUNCTION_DECL, fnname, fntype);
339 for (t = param_decl_list; t; t = DECL_CHAIN (t))
340 DECL_CONTEXT (t) = fndecl;
341 DECL_ARGUMENTS (fndecl) = param_decl_list;
343 = build_decl (input_location, RESULT_DECL, 0, return_type);
344 DECL_CONTEXT (DECL_RESULT (fndecl)) = fndecl;
346 /* The function has been created by the compiler and we don't
347 want to emit debug info for it. */
348 DECL_ARTIFICIAL (fndecl) = 1;
349 DECL_IGNORED_P (fndecl) = 1;
351 /* It is supposed to be "const" and never throw. */
352 TREE_READONLY (fndecl) = 1;
353 TREE_NOTHROW (fndecl) = 1;
355 /* We want it to be inlined when this is deemed profitable, as
356 well as discarded if every call has been integrated. */
357 DECL_DECLARED_INLINE_P (fndecl) = 1;
359 /* It is made up of a unique return statement. */
360 DECL_INITIAL (fndecl) = make_node (BLOCK);
361 BLOCK_SUPERCONTEXT (DECL_INITIAL (fndecl)) = fndecl;
362 t = build2 (MODIFY_EXPR, return_type, DECL_RESULT (fndecl), size);
363 DECL_SAVED_TREE (fndecl) = build1 (RETURN_EXPR, void_type_node, t);
364 TREE_STATIC (fndecl) = 1;
366 /* Put it onto the list of size functions. */
367 VEC_safe_push (tree, gc, size_functions, fndecl);
369 /* Replace the original expression with a call to the size function. */
370 return build_call_expr_loc_vec (UNKNOWN_LOCATION, fndecl, args);
373 /* Take, queue and compile all the size functions. It is essential that
374 the size functions be gimplified at the very end of the compilation
375 in order to guarantee transparent handling of self-referential sizes.
376 Otherwise the GENERIC inliner would not be able to inline them back
377 at each of their call sites, thus creating artificial non-constant
378 size expressions which would trigger nasty problems later on. */
381 finalize_size_functions (void)
386 for (i = 0; VEC_iterate(tree, size_functions, i, fndecl); i++)
388 dump_function (TDI_original, fndecl);
389 gimplify_function_tree (fndecl);
390 dump_function (TDI_generic, fndecl);
391 cgraph_finalize_function (fndecl, false);
394 VEC_free (tree, gc, size_functions);
397 /* Return the machine mode to use for a nonscalar of SIZE bits. The
398 mode must be in class MCLASS, and have exactly that many value bits;
399 it may have padding as well. If LIMIT is nonzero, modes of wider
400 than MAX_FIXED_MODE_SIZE will not be used. */
403 mode_for_size (unsigned int size, enum mode_class mclass, int limit)
405 enum machine_mode mode;
407 if (limit && size > MAX_FIXED_MODE_SIZE)
410 /* Get the first mode which has this size, in the specified class. */
411 for (mode = GET_CLASS_NARROWEST_MODE (mclass); mode != VOIDmode;
412 mode = GET_MODE_WIDER_MODE (mode))
413 if (GET_MODE_PRECISION (mode) == size)
419 /* Similar, except passed a tree node. */
422 mode_for_size_tree (const_tree size, enum mode_class mclass, int limit)
424 unsigned HOST_WIDE_INT uhwi;
427 if (!host_integerp (size, 1))
429 uhwi = tree_low_cst (size, 1);
433 return mode_for_size (ui, mclass, limit);
436 /* Similar, but never return BLKmode; return the narrowest mode that
437 contains at least the requested number of value bits. */
440 smallest_mode_for_size (unsigned int size, enum mode_class mclass)
442 enum machine_mode mode;
444 /* Get the first mode which has at least this size, in the
446 for (mode = GET_CLASS_NARROWEST_MODE (mclass); mode != VOIDmode;
447 mode = GET_MODE_WIDER_MODE (mode))
448 if (GET_MODE_PRECISION (mode) >= size)
454 /* Find an integer mode of the exact same size, or BLKmode on failure. */
457 int_mode_for_mode (enum machine_mode mode)
459 switch (GET_MODE_CLASS (mode))
462 case MODE_PARTIAL_INT:
465 case MODE_COMPLEX_INT:
466 case MODE_COMPLEX_FLOAT:
468 case MODE_DECIMAL_FLOAT:
469 case MODE_VECTOR_INT:
470 case MODE_VECTOR_FLOAT:
475 case MODE_VECTOR_FRACT:
476 case MODE_VECTOR_ACCUM:
477 case MODE_VECTOR_UFRACT:
478 case MODE_VECTOR_UACCUM:
479 mode = mode_for_size (GET_MODE_BITSIZE (mode), MODE_INT, 0);
486 /* ... fall through ... */
496 /* Find a mode that is suitable for representing a vector with
497 NUNITS elements of mode INNERMODE. Returns BLKmode if there
498 is no suitable mode. */
501 mode_for_vector (enum machine_mode innermode, unsigned nunits)
503 enum machine_mode mode;
505 /* First, look for a supported vector type. */
506 if (SCALAR_FLOAT_MODE_P (innermode))
507 mode = MIN_MODE_VECTOR_FLOAT;
508 else if (SCALAR_FRACT_MODE_P (innermode))
509 mode = MIN_MODE_VECTOR_FRACT;
510 else if (SCALAR_UFRACT_MODE_P (innermode))
511 mode = MIN_MODE_VECTOR_UFRACT;
512 else if (SCALAR_ACCUM_MODE_P (innermode))
513 mode = MIN_MODE_VECTOR_ACCUM;
514 else if (SCALAR_UACCUM_MODE_P (innermode))
515 mode = MIN_MODE_VECTOR_UACCUM;
517 mode = MIN_MODE_VECTOR_INT;
519 /* Do not check vector_mode_supported_p here. We'll do that
520 later in vector_type_mode. */
521 for (; mode != VOIDmode ; mode = GET_MODE_WIDER_MODE (mode))
522 if (GET_MODE_NUNITS (mode) == nunits
523 && GET_MODE_INNER (mode) == innermode)
526 /* For integers, try mapping it to a same-sized scalar mode. */
528 && GET_MODE_CLASS (innermode) == MODE_INT)
529 mode = mode_for_size (nunits * GET_MODE_BITSIZE (innermode),
533 || (GET_MODE_CLASS (mode) == MODE_INT
534 && !have_regs_of_mode[mode]))
540 /* Return the alignment of MODE. This will be bounded by 1 and
541 BIGGEST_ALIGNMENT. */
544 get_mode_alignment (enum machine_mode mode)
546 return MIN (BIGGEST_ALIGNMENT, MAX (1, mode_base_align[mode]*BITS_PER_UNIT));
549 /* Return the natural mode of an array, given that it is SIZE bytes in
550 total and has elements of type ELEM_TYPE. */
552 static enum machine_mode
553 mode_for_array (tree elem_type, tree size)
556 unsigned HOST_WIDE_INT int_size, int_elem_size;
559 /* One-element arrays get the component type's mode. */
560 elem_size = TYPE_SIZE (elem_type);
561 if (simple_cst_equal (size, elem_size))
562 return TYPE_MODE (elem_type);
565 if (host_integerp (size, 1) && host_integerp (elem_size, 1))
567 int_size = tree_low_cst (size, 1);
568 int_elem_size = tree_low_cst (elem_size, 1);
569 if (int_elem_size > 0
570 && int_size % int_elem_size == 0
571 && targetm.array_mode_supported_p (TYPE_MODE (elem_type),
572 int_size / int_elem_size))
575 return mode_for_size_tree (size, MODE_INT, limit_p);
578 /* Subroutine of layout_decl: Force alignment required for the data type.
579 But if the decl itself wants greater alignment, don't override that. */
582 do_type_align (tree type, tree decl)
584 if (TYPE_ALIGN (type) > DECL_ALIGN (decl))
586 DECL_ALIGN (decl) = TYPE_ALIGN (type);
587 if (TREE_CODE (decl) == FIELD_DECL)
588 DECL_USER_ALIGN (decl) = TYPE_USER_ALIGN (type);
592 /* Set the size, mode and alignment of a ..._DECL node.
593 TYPE_DECL does need this for C++.
594 Note that LABEL_DECL and CONST_DECL nodes do not need this,
595 and FUNCTION_DECL nodes have them set up in a special (and simple) way.
596 Don't call layout_decl for them.
598 KNOWN_ALIGN is the amount of alignment we can assume this
599 decl has with no special effort. It is relevant only for FIELD_DECLs
600 and depends on the previous fields.
601 All that matters about KNOWN_ALIGN is which powers of 2 divide it.
602 If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
603 the record will be aligned to suit. */
606 layout_decl (tree decl, unsigned int known_align)
608 tree type = TREE_TYPE (decl);
609 enum tree_code code = TREE_CODE (decl);
611 location_t loc = DECL_SOURCE_LOCATION (decl);
613 if (code == CONST_DECL)
616 gcc_assert (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL
617 || code == TYPE_DECL ||code == FIELD_DECL);
619 rtl = DECL_RTL_IF_SET (decl);
621 if (type == error_mark_node)
622 type = void_type_node;
624 /* Usually the size and mode come from the data type without change,
625 however, the front-end may set the explicit width of the field, so its
626 size may not be the same as the size of its type. This happens with
627 bitfields, of course (an `int' bitfield may be only 2 bits, say), but it
628 also happens with other fields. For example, the C++ front-end creates
629 zero-sized fields corresponding to empty base classes, and depends on
630 layout_type setting DECL_FIELD_BITPOS correctly for the field. Set the
631 size in bytes from the size in bits. If we have already set the mode,
632 don't set it again since we can be called twice for FIELD_DECLs. */
634 DECL_UNSIGNED (decl) = TYPE_UNSIGNED (type);
635 if (DECL_MODE (decl) == VOIDmode)
636 DECL_MODE (decl) = TYPE_MODE (type);
638 if (DECL_SIZE (decl) == 0)
640 DECL_SIZE (decl) = TYPE_SIZE (type);
641 DECL_SIZE_UNIT (decl) = TYPE_SIZE_UNIT (type);
643 else if (DECL_SIZE_UNIT (decl) == 0)
644 DECL_SIZE_UNIT (decl)
645 = fold_convert_loc (loc, sizetype,
646 size_binop_loc (loc, CEIL_DIV_EXPR, DECL_SIZE (decl),
649 if (code != FIELD_DECL)
650 /* For non-fields, update the alignment from the type. */
651 do_type_align (type, decl);
653 /* For fields, it's a bit more complicated... */
655 bool old_user_align = DECL_USER_ALIGN (decl);
656 bool zero_bitfield = false;
657 bool packed_p = DECL_PACKED (decl);
660 if (DECL_BIT_FIELD (decl))
662 DECL_BIT_FIELD_TYPE (decl) = type;
664 /* A zero-length bit-field affects the alignment of the next
665 field. In essence such bit-fields are not influenced by
666 any packing due to #pragma pack or attribute packed. */
667 if (integer_zerop (DECL_SIZE (decl))
668 && ! targetm.ms_bitfield_layout_p (DECL_FIELD_CONTEXT (decl)))
670 zero_bitfield = true;
672 #ifdef PCC_BITFIELD_TYPE_MATTERS
673 if (PCC_BITFIELD_TYPE_MATTERS)
674 do_type_align (type, decl);
678 #ifdef EMPTY_FIELD_BOUNDARY
679 if (EMPTY_FIELD_BOUNDARY > DECL_ALIGN (decl))
681 DECL_ALIGN (decl) = EMPTY_FIELD_BOUNDARY;
682 DECL_USER_ALIGN (decl) = 0;
688 /* See if we can use an ordinary integer mode for a bit-field.
689 Conditions are: a fixed size that is correct for another mode,
690 occupying a complete byte or bytes on proper boundary,
691 and not volatile or not -fstrict-volatile-bitfields. */
692 if (TYPE_SIZE (type) != 0
693 && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
694 && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT
695 && !(TREE_THIS_VOLATILE (decl)
696 && flag_strict_volatile_bitfields > 0))
698 enum machine_mode xmode
699 = mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);
700 unsigned int xalign = GET_MODE_ALIGNMENT (xmode);
703 && !(xalign > BITS_PER_UNIT && DECL_PACKED (decl))
704 && (known_align == 0 || known_align >= xalign))
706 DECL_ALIGN (decl) = MAX (xalign, DECL_ALIGN (decl));
707 DECL_MODE (decl) = xmode;
708 DECL_BIT_FIELD (decl) = 0;
712 /* Turn off DECL_BIT_FIELD if we won't need it set. */
713 if (TYPE_MODE (type) == BLKmode && DECL_MODE (decl) == BLKmode
714 && known_align >= TYPE_ALIGN (type)
715 && DECL_ALIGN (decl) >= TYPE_ALIGN (type))
716 DECL_BIT_FIELD (decl) = 0;
718 else if (packed_p && DECL_USER_ALIGN (decl))
719 /* Don't touch DECL_ALIGN. For other packed fields, go ahead and
720 round up; we'll reduce it again below. We want packing to
721 supersede USER_ALIGN inherited from the type, but defer to
722 alignment explicitly specified on the field decl. */;
724 do_type_align (type, decl);
726 /* If the field is packed and not explicitly aligned, give it the
727 minimum alignment. Note that do_type_align may set
728 DECL_USER_ALIGN, so we need to check old_user_align instead. */
731 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT);
733 if (! packed_p && ! DECL_USER_ALIGN (decl))
735 /* Some targets (i.e. i386, VMS) limit struct field alignment
736 to a lower boundary than alignment of variables unless
737 it was overridden by attribute aligned. */
738 #ifdef BIGGEST_FIELD_ALIGNMENT
740 = MIN (DECL_ALIGN (decl), (unsigned) BIGGEST_FIELD_ALIGNMENT);
742 #ifdef ADJUST_FIELD_ALIGN
743 DECL_ALIGN (decl) = ADJUST_FIELD_ALIGN (decl, DECL_ALIGN (decl));
748 mfa = initial_max_fld_align * BITS_PER_UNIT;
750 mfa = maximum_field_alignment;
751 /* Should this be controlled by DECL_USER_ALIGN, too? */
753 DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), mfa);
756 /* Evaluate nonconstant size only once, either now or as soon as safe. */
757 if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
758 DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
759 if (DECL_SIZE_UNIT (decl) != 0
760 && TREE_CODE (DECL_SIZE_UNIT (decl)) != INTEGER_CST)
761 DECL_SIZE_UNIT (decl) = variable_size (DECL_SIZE_UNIT (decl));
763 /* If requested, warn about definitions of large data objects. */
765 && (code == VAR_DECL || code == PARM_DECL)
766 && ! DECL_EXTERNAL (decl))
768 tree size = DECL_SIZE_UNIT (decl);
770 if (size != 0 && TREE_CODE (size) == INTEGER_CST
771 && compare_tree_int (size, larger_than_size) > 0)
773 int size_as_int = TREE_INT_CST_LOW (size);
775 if (compare_tree_int (size, size_as_int) == 0)
776 warning (OPT_Wlarger_than_, "size of %q+D is %d bytes", decl, size_as_int);
778 warning (OPT_Wlarger_than_, "size of %q+D is larger than %wd bytes",
779 decl, larger_than_size);
783 /* If the RTL was already set, update its mode and mem attributes. */
786 PUT_MODE (rtl, DECL_MODE (decl));
787 SET_DECL_RTL (decl, 0);
788 set_mem_attributes (rtl, decl, 1);
789 SET_DECL_RTL (decl, rtl);
793 /* Given a VAR_DECL, PARM_DECL or RESULT_DECL, clears the results of
794 a previous call to layout_decl and calls it again. */
797 relayout_decl (tree decl)
799 DECL_SIZE (decl) = DECL_SIZE_UNIT (decl) = 0;
800 DECL_MODE (decl) = VOIDmode;
801 if (!DECL_USER_ALIGN (decl))
802 DECL_ALIGN (decl) = 0;
803 SET_DECL_RTL (decl, 0);
805 layout_decl (decl, 0);
808 /* Begin laying out type T, which may be a RECORD_TYPE, UNION_TYPE, or
809 QUAL_UNION_TYPE. Return a pointer to a struct record_layout_info which
810 is to be passed to all other layout functions for this record. It is the
811 responsibility of the caller to call `free' for the storage returned.
812 Note that garbage collection is not permitted until we finish laying
816 start_record_layout (tree t)
818 record_layout_info rli = XNEW (struct record_layout_info_s);
822 /* If the type has a minimum specified alignment (via an attribute
823 declaration, for example) use it -- otherwise, start with a
824 one-byte alignment. */
825 rli->record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (t));
826 rli->unpacked_align = rli->record_align;
827 rli->offset_align = MAX (rli->record_align, BIGGEST_ALIGNMENT);
829 #ifdef STRUCTURE_SIZE_BOUNDARY
830 /* Packed structures don't need to have minimum size. */
831 if (! TYPE_PACKED (t))
835 /* #pragma pack overrides STRUCTURE_SIZE_BOUNDARY. */
836 tmp = (unsigned) STRUCTURE_SIZE_BOUNDARY;
837 if (maximum_field_alignment != 0)
838 tmp = MIN (tmp, maximum_field_alignment);
839 rli->record_align = MAX (rli->record_align, tmp);
843 rli->offset = size_zero_node;
844 rli->bitpos = bitsize_zero_node;
846 rli->pending_statics = NULL;
847 rli->packed_maybe_necessary = 0;
848 rli->remaining_in_alignment = 0;
853 /* These four routines perform computations that convert between
854 the offset/bitpos forms and byte and bit offsets. */
857 bit_from_pos (tree offset, tree bitpos)
859 return size_binop (PLUS_EXPR, bitpos,
860 size_binop (MULT_EXPR,
861 fold_convert (bitsizetype, offset),
866 byte_from_pos (tree offset, tree bitpos)
868 return size_binop (PLUS_EXPR, offset,
869 fold_convert (sizetype,
870 size_binop (TRUNC_DIV_EXPR, bitpos,
871 bitsize_unit_node)));
875 pos_from_bit (tree *poffset, tree *pbitpos, unsigned int off_align,
878 *poffset = size_binop (MULT_EXPR,
879 fold_convert (sizetype,
880 size_binop (FLOOR_DIV_EXPR, pos,
881 bitsize_int (off_align))),
882 size_int (off_align / BITS_PER_UNIT));
883 *pbitpos = size_binop (FLOOR_MOD_EXPR, pos, bitsize_int (off_align));
886 /* Given a pointer to bit and byte offsets and an offset alignment,
887 normalize the offsets so they are within the alignment. */
890 normalize_offset (tree *poffset, tree *pbitpos, unsigned int off_align)
892 /* If the bit position is now larger than it should be, adjust it
894 if (compare_tree_int (*pbitpos, off_align) >= 0)
896 tree extra_aligns = size_binop (FLOOR_DIV_EXPR, *pbitpos,
897 bitsize_int (off_align));
900 = size_binop (PLUS_EXPR, *poffset,
901 size_binop (MULT_EXPR,
902 fold_convert (sizetype, extra_aligns),
903 size_int (off_align / BITS_PER_UNIT)));
906 = size_binop (FLOOR_MOD_EXPR, *pbitpos, bitsize_int (off_align));
910 /* Print debugging information about the information in RLI. */
913 debug_rli (record_layout_info rli)
915 print_node_brief (stderr, "type", rli->t, 0);
916 print_node_brief (stderr, "\noffset", rli->offset, 0);
917 print_node_brief (stderr, " bitpos", rli->bitpos, 0);
919 fprintf (stderr, "\naligns: rec = %u, unpack = %u, off = %u\n",
920 rli->record_align, rli->unpacked_align,
923 /* The ms_struct code is the only that uses this. */
924 if (targetm.ms_bitfield_layout_p (rli->t))
925 fprintf (stderr, "remaining in alignment = %u\n", rli->remaining_in_alignment);
927 if (rli->packed_maybe_necessary)
928 fprintf (stderr, "packed may be necessary\n");
930 if (!VEC_empty (tree, rli->pending_statics))
932 fprintf (stderr, "pending statics:\n");
933 debug_vec_tree (rli->pending_statics);
937 /* Given an RLI with a possibly-incremented BITPOS, adjust OFFSET and
938 BITPOS if necessary to keep BITPOS below OFFSET_ALIGN. */
941 normalize_rli (record_layout_info rli)
943 normalize_offset (&rli->offset, &rli->bitpos, rli->offset_align);
946 /* Returns the size in bytes allocated so far. */
949 rli_size_unit_so_far (record_layout_info rli)
951 return byte_from_pos (rli->offset, rli->bitpos);
954 /* Returns the size in bits allocated so far. */
957 rli_size_so_far (record_layout_info rli)
959 return bit_from_pos (rli->offset, rli->bitpos);
962 /* FIELD is about to be added to RLI->T. The alignment (in bits) of
963 the next available location within the record is given by KNOWN_ALIGN.
964 Update the variable alignment fields in RLI, and return the alignment
965 to give the FIELD. */
968 update_alignment_for_field (record_layout_info rli, tree field,
969 unsigned int known_align)
971 /* The alignment required for FIELD. */
972 unsigned int desired_align;
973 /* The type of this field. */
974 tree type = TREE_TYPE (field);
975 /* True if the field was explicitly aligned by the user. */
979 /* Do not attempt to align an ERROR_MARK node */
980 if (TREE_CODE (type) == ERROR_MARK)
983 /* Lay out the field so we know what alignment it needs. */
984 layout_decl (field, known_align);
985 desired_align = DECL_ALIGN (field);
986 user_align = DECL_USER_ALIGN (field);
988 is_bitfield = (type != error_mark_node
989 && DECL_BIT_FIELD_TYPE (field)
990 && ! integer_zerop (TYPE_SIZE (type)));
992 /* Record must have at least as much alignment as any field.
993 Otherwise, the alignment of the field within the record is
995 if (targetm.ms_bitfield_layout_p (rli->t))
997 /* Here, the alignment of the underlying type of a bitfield can
998 affect the alignment of a record; even a zero-sized field
999 can do this. The alignment should be to the alignment of
1000 the type, except that for zero-size bitfields this only
1001 applies if there was an immediately prior, nonzero-size
1002 bitfield. (That's the way it is, experimentally.) */
1003 if ((!is_bitfield && !DECL_PACKED (field))
1004 || (!integer_zerop (DECL_SIZE (field))
1005 ? !DECL_PACKED (field)
1007 && DECL_BIT_FIELD_TYPE (rli->prev_field)
1008 && ! integer_zerop (DECL_SIZE (rli->prev_field)))))
1010 unsigned int type_align = TYPE_ALIGN (type);
1011 type_align = MAX (type_align, desired_align);
1012 if (maximum_field_alignment != 0)
1013 type_align = MIN (type_align, maximum_field_alignment);
1014 rli->record_align = MAX (rli->record_align, type_align);
1015 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
1018 #ifdef PCC_BITFIELD_TYPE_MATTERS
1019 else if (is_bitfield && PCC_BITFIELD_TYPE_MATTERS)
1021 /* Named bit-fields cause the entire structure to have the
1022 alignment implied by their type. Some targets also apply the same
1023 rules to unnamed bitfields. */
1024 if (DECL_NAME (field) != 0
1025 || targetm.align_anon_bitfield ())
1027 unsigned int type_align = TYPE_ALIGN (type);
1029 #ifdef ADJUST_FIELD_ALIGN
1030 if (! TYPE_USER_ALIGN (type))
1031 type_align = ADJUST_FIELD_ALIGN (field, type_align);
1034 /* Targets might chose to handle unnamed and hence possibly
1035 zero-width bitfield. Those are not influenced by #pragmas
1036 or packed attributes. */
1037 if (integer_zerop (DECL_SIZE (field)))
1039 if (initial_max_fld_align)
1040 type_align = MIN (type_align,
1041 initial_max_fld_align * BITS_PER_UNIT);
1043 else if (maximum_field_alignment != 0)
1044 type_align = MIN (type_align, maximum_field_alignment);
1045 else if (DECL_PACKED (field))
1046 type_align = MIN (type_align, BITS_PER_UNIT);
1048 /* The alignment of the record is increased to the maximum
1049 of the current alignment, the alignment indicated on the
1050 field (i.e., the alignment specified by an __aligned__
1051 attribute), and the alignment indicated by the type of
1053 rli->record_align = MAX (rli->record_align, desired_align);
1054 rli->record_align = MAX (rli->record_align, type_align);
1057 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
1058 user_align |= TYPE_USER_ALIGN (type);
1064 rli->record_align = MAX (rli->record_align, desired_align);
1065 rli->unpacked_align = MAX (rli->unpacked_align, TYPE_ALIGN (type));
1068 TYPE_USER_ALIGN (rli->t) |= user_align;
1070 return desired_align;
1073 /* Called from place_field to handle unions. */
1076 place_union_field (record_layout_info rli, tree field)
1078 update_alignment_for_field (rli, field, /*known_align=*/0);
1080 DECL_FIELD_OFFSET (field) = size_zero_node;
1081 DECL_FIELD_BIT_OFFSET (field) = bitsize_zero_node;
1082 SET_DECL_OFFSET_ALIGN (field, BIGGEST_ALIGNMENT);
1084 /* If this is an ERROR_MARK return *after* having set the
1085 field at the start of the union. This helps when parsing
1087 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK)
1090 /* We assume the union's size will be a multiple of a byte so we don't
1091 bother with BITPOS. */
1092 if (TREE_CODE (rli->t) == UNION_TYPE)
1093 rli->offset = size_binop (MAX_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1094 else if (TREE_CODE (rli->t) == QUAL_UNION_TYPE)
1095 rli->offset = fold_build3 (COND_EXPR, sizetype, DECL_QUALIFIER (field),
1096 DECL_SIZE_UNIT (field), rli->offset);
1099 #if defined (PCC_BITFIELD_TYPE_MATTERS) || defined (BITFIELD_NBYTES_LIMITED)
1100 /* A bitfield of SIZE with a required access alignment of ALIGN is allocated
1101 at BYTE_OFFSET / BIT_OFFSET. Return nonzero if the field would span more
1102 units of alignment than the underlying TYPE. */
1104 excess_unit_span (HOST_WIDE_INT byte_offset, HOST_WIDE_INT bit_offset,
1105 HOST_WIDE_INT size, HOST_WIDE_INT align, tree type)
1107 /* Note that the calculation of OFFSET might overflow; we calculate it so
1108 that we still get the right result as long as ALIGN is a power of two. */
1109 unsigned HOST_WIDE_INT offset = byte_offset * BITS_PER_UNIT + bit_offset;
1111 offset = offset % align;
1112 return ((offset + size + align - 1) / align
1113 > ((unsigned HOST_WIDE_INT) tree_low_cst (TYPE_SIZE (type), 1)
1118 /* RLI contains information about the layout of a RECORD_TYPE. FIELD
1119 is a FIELD_DECL to be added after those fields already present in
1120 T. (FIELD is not actually added to the TYPE_FIELDS list here;
1121 callers that desire that behavior must manually perform that step.) */
1124 place_field (record_layout_info rli, tree field)
1126 /* The alignment required for FIELD. */
1127 unsigned int desired_align;
1128 /* The alignment FIELD would have if we just dropped it into the
1129 record as it presently stands. */
1130 unsigned int known_align;
1131 unsigned int actual_align;
1132 /* The type of this field. */
1133 tree type = TREE_TYPE (field);
1135 gcc_assert (TREE_CODE (field) != ERROR_MARK);
1137 /* If FIELD is static, then treat it like a separate variable, not
1138 really like a structure field. If it is a FUNCTION_DECL, it's a
1139 method. In both cases, all we do is lay out the decl, and we do
1140 it *after* the record is laid out. */
1141 if (TREE_CODE (field) == VAR_DECL)
1143 VEC_safe_push (tree, gc, rli->pending_statics, field);
1147 /* Enumerators and enum types which are local to this class need not
1148 be laid out. Likewise for initialized constant fields. */
1149 else if (TREE_CODE (field) != FIELD_DECL)
1152 /* Unions are laid out very differently than records, so split
1153 that code off to another function. */
1154 else if (TREE_CODE (rli->t) != RECORD_TYPE)
1156 place_union_field (rli, field);
1160 else if (TREE_CODE (type) == ERROR_MARK)
1162 /* Place this field at the current allocation position, so we
1163 maintain monotonicity. */
1164 DECL_FIELD_OFFSET (field) = rli->offset;
1165 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1166 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1170 /* Work out the known alignment so far. Note that A & (-A) is the
1171 value of the least-significant bit in A that is one. */
1172 if (! integer_zerop (rli->bitpos))
1173 known_align = (tree_low_cst (rli->bitpos, 1)
1174 & - tree_low_cst (rli->bitpos, 1));
1175 else if (integer_zerop (rli->offset))
1177 else if (host_integerp (rli->offset, 1))
1178 known_align = (BITS_PER_UNIT
1179 * (tree_low_cst (rli->offset, 1)
1180 & - tree_low_cst (rli->offset, 1)));
1182 known_align = rli->offset_align;
1184 desired_align = update_alignment_for_field (rli, field, known_align);
1185 if (known_align == 0)
1186 known_align = MAX (BIGGEST_ALIGNMENT, rli->record_align);
1188 if (warn_packed && DECL_PACKED (field))
1190 if (known_align >= TYPE_ALIGN (type))
1192 if (TYPE_ALIGN (type) > desired_align)
1194 if (STRICT_ALIGNMENT)
1195 warning (OPT_Wattributes, "packed attribute causes "
1196 "inefficient alignment for %q+D", field);
1197 /* Don't warn if DECL_PACKED was set by the type. */
1198 else if (!TYPE_PACKED (rli->t))
1199 warning (OPT_Wattributes, "packed attribute is "
1200 "unnecessary for %q+D", field);
1204 rli->packed_maybe_necessary = 1;
1207 /* Does this field automatically have alignment it needs by virtue
1208 of the fields that precede it and the record's own alignment?
1209 We already align ms_struct fields, so don't re-align them. */
1210 if (known_align < desired_align
1211 && !targetm.ms_bitfield_layout_p (rli->t))
1213 /* No, we need to skip space before this field.
1214 Bump the cumulative size to multiple of field alignment. */
1216 if (DECL_SOURCE_LOCATION (field) != BUILTINS_LOCATION)
1217 warning (OPT_Wpadded, "padding struct to align %q+D", field);
1219 /* If the alignment is still within offset_align, just align
1220 the bit position. */
1221 if (desired_align < rli->offset_align)
1222 rli->bitpos = round_up (rli->bitpos, desired_align);
1225 /* First adjust OFFSET by the partial bits, then align. */
1227 = size_binop (PLUS_EXPR, rli->offset,
1228 fold_convert (sizetype,
1229 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1230 bitsize_unit_node)));
1231 rli->bitpos = bitsize_zero_node;
1233 rli->offset = round_up (rli->offset, desired_align / BITS_PER_UNIT);
1236 if (! TREE_CONSTANT (rli->offset))
1237 rli->offset_align = desired_align;
1241 /* Handle compatibility with PCC. Note that if the record has any
1242 variable-sized fields, we need not worry about compatibility. */
1243 #ifdef PCC_BITFIELD_TYPE_MATTERS
1244 if (PCC_BITFIELD_TYPE_MATTERS
1245 && ! targetm.ms_bitfield_layout_p (rli->t)
1246 && TREE_CODE (field) == FIELD_DECL
1247 && type != error_mark_node
1248 && DECL_BIT_FIELD (field)
1249 && (! DECL_PACKED (field)
1250 /* Enter for these packed fields only to issue a warning. */
1251 || TYPE_ALIGN (type) <= BITS_PER_UNIT)
1252 && maximum_field_alignment == 0
1253 && ! integer_zerop (DECL_SIZE (field))
1254 && host_integerp (DECL_SIZE (field), 1)
1255 && host_integerp (rli->offset, 1)
1256 && host_integerp (TYPE_SIZE (type), 1))
1258 unsigned int type_align = TYPE_ALIGN (type);
1259 tree dsize = DECL_SIZE (field);
1260 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
1261 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
1262 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
1264 #ifdef ADJUST_FIELD_ALIGN
1265 if (! TYPE_USER_ALIGN (type))
1266 type_align = ADJUST_FIELD_ALIGN (field, type_align);
1269 /* A bit field may not span more units of alignment of its type
1270 than its type itself. Advance to next boundary if necessary. */
1271 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
1273 if (DECL_PACKED (field))
1275 if (warn_packed_bitfield_compat == 1)
1278 "offset of packed bit-field %qD has changed in GCC 4.4",
1282 rli->bitpos = round_up (rli->bitpos, type_align);
1285 if (! DECL_PACKED (field))
1286 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
1290 #ifdef BITFIELD_NBYTES_LIMITED
1291 if (BITFIELD_NBYTES_LIMITED
1292 && ! targetm.ms_bitfield_layout_p (rli->t)
1293 && TREE_CODE (field) == FIELD_DECL
1294 && type != error_mark_node
1295 && DECL_BIT_FIELD_TYPE (field)
1296 && ! DECL_PACKED (field)
1297 && ! integer_zerop (DECL_SIZE (field))
1298 && host_integerp (DECL_SIZE (field), 1)
1299 && host_integerp (rli->offset, 1)
1300 && host_integerp (TYPE_SIZE (type), 1))
1302 unsigned int type_align = TYPE_ALIGN (type);
1303 tree dsize = DECL_SIZE (field);
1304 HOST_WIDE_INT field_size = tree_low_cst (dsize, 1);
1305 HOST_WIDE_INT offset = tree_low_cst (rli->offset, 0);
1306 HOST_WIDE_INT bit_offset = tree_low_cst (rli->bitpos, 0);
1308 #ifdef ADJUST_FIELD_ALIGN
1309 if (! TYPE_USER_ALIGN (type))
1310 type_align = ADJUST_FIELD_ALIGN (field, type_align);
1313 if (maximum_field_alignment != 0)
1314 type_align = MIN (type_align, maximum_field_alignment);
1315 /* ??? This test is opposite the test in the containing if
1316 statement, so this code is unreachable currently. */
1317 else if (DECL_PACKED (field))
1318 type_align = MIN (type_align, BITS_PER_UNIT);
1320 /* A bit field may not span the unit of alignment of its type.
1321 Advance to next boundary if necessary. */
1322 if (excess_unit_span (offset, bit_offset, field_size, type_align, type))
1323 rli->bitpos = round_up (rli->bitpos, type_align);
1325 TYPE_USER_ALIGN (rli->t) |= TYPE_USER_ALIGN (type);
1329 /* See the docs for TARGET_MS_BITFIELD_LAYOUT_P for details.
1331 When a bit field is inserted into a packed record, the whole
1332 size of the underlying type is used by one or more same-size
1333 adjacent bitfields. (That is, if its long:3, 32 bits is
1334 used in the record, and any additional adjacent long bitfields are
1335 packed into the same chunk of 32 bits. However, if the size
1336 changes, a new field of that size is allocated.) In an unpacked
1337 record, this is the same as using alignment, but not equivalent
1340 Note: for compatibility, we use the type size, not the type alignment
1341 to determine alignment, since that matches the documentation */
1343 if (targetm.ms_bitfield_layout_p (rli->t))
1345 tree prev_saved = rli->prev_field;
1346 tree prev_type = prev_saved ? DECL_BIT_FIELD_TYPE (prev_saved) : NULL;
1348 /* This is a bitfield if it exists. */
1349 if (rli->prev_field)
1351 /* If both are bitfields, nonzero, and the same size, this is
1352 the middle of a run. Zero declared size fields are special
1353 and handled as "end of run". (Note: it's nonzero declared
1354 size, but equal type sizes!) (Since we know that both
1355 the current and previous fields are bitfields by the
1356 time we check it, DECL_SIZE must be present for both.) */
1357 if (DECL_BIT_FIELD_TYPE (field)
1358 && !integer_zerop (DECL_SIZE (field))
1359 && !integer_zerop (DECL_SIZE (rli->prev_field))
1360 && host_integerp (DECL_SIZE (rli->prev_field), 0)
1361 && host_integerp (TYPE_SIZE (type), 0)
1362 && simple_cst_equal (TYPE_SIZE (type), TYPE_SIZE (prev_type)))
1364 /* We're in the middle of a run of equal type size fields; make
1365 sure we realign if we run out of bits. (Not decl size,
1367 HOST_WIDE_INT bitsize = tree_low_cst (DECL_SIZE (field), 1);
1369 if (rli->remaining_in_alignment < bitsize)
1371 HOST_WIDE_INT typesize = tree_low_cst (TYPE_SIZE (type), 1);
1373 /* out of bits; bump up to next 'word'. */
1375 = size_binop (PLUS_EXPR, rli->bitpos,
1376 bitsize_int (rli->remaining_in_alignment));
1377 rli->prev_field = field;
1378 if (typesize < bitsize)
1379 rli->remaining_in_alignment = 0;
1381 rli->remaining_in_alignment = typesize - bitsize;
1384 rli->remaining_in_alignment -= bitsize;
1388 /* End of a run: if leaving a run of bitfields of the same type
1389 size, we have to "use up" the rest of the bits of the type
1392 Compute the new position as the sum of the size for the prior
1393 type and where we first started working on that type.
1394 Note: since the beginning of the field was aligned then
1395 of course the end will be too. No round needed. */
1397 if (!integer_zerop (DECL_SIZE (rli->prev_field)))
1400 = size_binop (PLUS_EXPR, rli->bitpos,
1401 bitsize_int (rli->remaining_in_alignment));
1404 /* We "use up" size zero fields; the code below should behave
1405 as if the prior field was not a bitfield. */
1408 /* Cause a new bitfield to be captured, either this time (if
1409 currently a bitfield) or next time we see one. */
1410 if (!DECL_BIT_FIELD_TYPE(field)
1411 || integer_zerop (DECL_SIZE (field)))
1412 rli->prev_field = NULL;
1415 normalize_rli (rli);
1418 /* If we're starting a new run of same size type bitfields
1419 (or a run of non-bitfields), set up the "first of the run"
1422 That is, if the current field is not a bitfield, or if there
1423 was a prior bitfield the type sizes differ, or if there wasn't
1424 a prior bitfield the size of the current field is nonzero.
1426 Note: we must be sure to test ONLY the type size if there was
1427 a prior bitfield and ONLY for the current field being zero if
1430 if (!DECL_BIT_FIELD_TYPE (field)
1431 || (prev_saved != NULL
1432 ? !simple_cst_equal (TYPE_SIZE (type), TYPE_SIZE (prev_type))
1433 : !integer_zerop (DECL_SIZE (field)) ))
1435 /* Never smaller than a byte for compatibility. */
1436 unsigned int type_align = BITS_PER_UNIT;
1438 /* (When not a bitfield), we could be seeing a flex array (with
1439 no DECL_SIZE). Since we won't be using remaining_in_alignment
1440 until we see a bitfield (and come by here again) we just skip
1442 if (DECL_SIZE (field) != NULL
1443 && host_integerp (TYPE_SIZE (TREE_TYPE (field)), 1)
1444 && host_integerp (DECL_SIZE (field), 1))
1446 unsigned HOST_WIDE_INT bitsize
1447 = tree_low_cst (DECL_SIZE (field), 1);
1448 unsigned HOST_WIDE_INT typesize
1449 = tree_low_cst (TYPE_SIZE (TREE_TYPE (field)), 1);
1451 if (typesize < bitsize)
1452 rli->remaining_in_alignment = 0;
1454 rli->remaining_in_alignment = typesize - bitsize;
1457 /* Now align (conventionally) for the new type. */
1458 type_align = TYPE_ALIGN (TREE_TYPE (field));
1460 if (maximum_field_alignment != 0)
1461 type_align = MIN (type_align, maximum_field_alignment);
1463 rli->bitpos = round_up (rli->bitpos, type_align);
1465 /* If we really aligned, don't allow subsequent bitfields
1467 rli->prev_field = NULL;
1471 /* Offset so far becomes the position of this field after normalizing. */
1472 normalize_rli (rli);
1473 DECL_FIELD_OFFSET (field) = rli->offset;
1474 DECL_FIELD_BIT_OFFSET (field) = rli->bitpos;
1475 SET_DECL_OFFSET_ALIGN (field, rli->offset_align);
1477 /* If this field ended up more aligned than we thought it would be (we
1478 approximate this by seeing if its position changed), lay out the field
1479 again; perhaps we can use an integral mode for it now. */
1480 if (! integer_zerop (DECL_FIELD_BIT_OFFSET (field)))
1481 actual_align = (tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1)
1482 & - tree_low_cst (DECL_FIELD_BIT_OFFSET (field), 1));
1483 else if (integer_zerop (DECL_FIELD_OFFSET (field)))
1484 actual_align = MAX (BIGGEST_ALIGNMENT, rli->record_align);
1485 else if (host_integerp (DECL_FIELD_OFFSET (field), 1))
1486 actual_align = (BITS_PER_UNIT
1487 * (tree_low_cst (DECL_FIELD_OFFSET (field), 1)
1488 & - tree_low_cst (DECL_FIELD_OFFSET (field), 1)));
1490 actual_align = DECL_OFFSET_ALIGN (field);
1491 /* ACTUAL_ALIGN is still the actual alignment *within the record* .
1492 store / extract bit field operations will check the alignment of the
1493 record against the mode of bit fields. */
1495 if (known_align != actual_align)
1496 layout_decl (field, actual_align);
1498 if (rli->prev_field == NULL && DECL_BIT_FIELD_TYPE (field))
1499 rli->prev_field = field;
1501 /* Now add size of this field to the size of the record. If the size is
1502 not constant, treat the field as being a multiple of bytes and just
1503 adjust the offset, resetting the bit position. Otherwise, apportion the
1504 size amongst the bit position and offset. First handle the case of an
1505 unspecified size, which can happen when we have an invalid nested struct
1506 definition, such as struct j { struct j { int i; } }. The error message
1507 is printed in finish_struct. */
1508 if (DECL_SIZE (field) == 0)
1510 else if (TREE_CODE (DECL_SIZE (field)) != INTEGER_CST
1511 || TREE_OVERFLOW (DECL_SIZE (field)))
1514 = size_binop (PLUS_EXPR, rli->offset,
1515 fold_convert (sizetype,
1516 size_binop (CEIL_DIV_EXPR, rli->bitpos,
1517 bitsize_unit_node)));
1519 = size_binop (PLUS_EXPR, rli->offset, DECL_SIZE_UNIT (field));
1520 rli->bitpos = bitsize_zero_node;
1521 rli->offset_align = MIN (rli->offset_align, desired_align);
1523 else if (targetm.ms_bitfield_layout_p (rli->t))
1525 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1527 /* If we ended a bitfield before the full length of the type then
1528 pad the struct out to the full length of the last type. */
1529 if ((DECL_CHAIN (field) == NULL
1530 || TREE_CODE (DECL_CHAIN (field)) != FIELD_DECL)
1531 && DECL_BIT_FIELD_TYPE (field)
1532 && !integer_zerop (DECL_SIZE (field)))
1533 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos,
1534 bitsize_int (rli->remaining_in_alignment));
1536 normalize_rli (rli);
1540 rli->bitpos = size_binop (PLUS_EXPR, rli->bitpos, DECL_SIZE (field));
1541 normalize_rli (rli);
1545 /* Assuming that all the fields have been laid out, this function uses
1546 RLI to compute the final TYPE_SIZE, TYPE_ALIGN, etc. for the type
1547 indicated by RLI. */
1550 finalize_record_size (record_layout_info rli)
1552 tree unpadded_size, unpadded_size_unit;
1554 /* Now we want just byte and bit offsets, so set the offset alignment
1555 to be a byte and then normalize. */
1556 rli->offset_align = BITS_PER_UNIT;
1557 normalize_rli (rli);
1559 /* Determine the desired alignment. */
1560 #ifdef ROUND_TYPE_ALIGN
1561 TYPE_ALIGN (rli->t) = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t),
1564 TYPE_ALIGN (rli->t) = MAX (TYPE_ALIGN (rli->t), rli->record_align);
1567 /* Compute the size so far. Be sure to allow for extra bits in the
1568 size in bytes. We have guaranteed above that it will be no more
1569 than a single byte. */
1570 unpadded_size = rli_size_so_far (rli);
1571 unpadded_size_unit = rli_size_unit_so_far (rli);
1572 if (! integer_zerop (rli->bitpos))
1574 = size_binop (PLUS_EXPR, unpadded_size_unit, size_one_node);
1576 /* Round the size up to be a multiple of the required alignment. */
1577 TYPE_SIZE (rli->t) = round_up (unpadded_size, TYPE_ALIGN (rli->t));
1578 TYPE_SIZE_UNIT (rli->t)
1579 = round_up (unpadded_size_unit, TYPE_ALIGN_UNIT (rli->t));
1581 if (TREE_CONSTANT (unpadded_size)
1582 && simple_cst_equal (unpadded_size, TYPE_SIZE (rli->t)) == 0
1583 && input_location != BUILTINS_LOCATION)
1584 warning (OPT_Wpadded, "padding struct size to alignment boundary");
1586 if (warn_packed && TREE_CODE (rli->t) == RECORD_TYPE
1587 && TYPE_PACKED (rli->t) && ! rli->packed_maybe_necessary
1588 && TREE_CONSTANT (unpadded_size))
1592 #ifdef ROUND_TYPE_ALIGN
1594 = ROUND_TYPE_ALIGN (rli->t, TYPE_ALIGN (rli->t), rli->unpacked_align);
1596 rli->unpacked_align = MAX (TYPE_ALIGN (rli->t), rli->unpacked_align);
1599 unpacked_size = round_up (TYPE_SIZE (rli->t), rli->unpacked_align);
1600 if (simple_cst_equal (unpacked_size, TYPE_SIZE (rli->t)))
1602 if (TYPE_NAME (rli->t))
1606 if (TREE_CODE (TYPE_NAME (rli->t)) == IDENTIFIER_NODE)
1607 name = TYPE_NAME (rli->t);
1609 name = DECL_NAME (TYPE_NAME (rli->t));
1611 if (STRICT_ALIGNMENT)
1612 warning (OPT_Wpacked, "packed attribute causes inefficient "
1613 "alignment for %qE", name);
1615 warning (OPT_Wpacked,
1616 "packed attribute is unnecessary for %qE", name);
1620 if (STRICT_ALIGNMENT)
1621 warning (OPT_Wpacked,
1622 "packed attribute causes inefficient alignment");
1624 warning (OPT_Wpacked, "packed attribute is unnecessary");
1630 /* Compute the TYPE_MODE for the TYPE (which is a RECORD_TYPE). */
1633 compute_record_mode (tree type)
1636 enum machine_mode mode = VOIDmode;
1638 /* Most RECORD_TYPEs have BLKmode, so we start off assuming that.
1639 However, if possible, we use a mode that fits in a register
1640 instead, in order to allow for better optimization down the
1642 SET_TYPE_MODE (type, BLKmode);
1644 if (! host_integerp (TYPE_SIZE (type), 1))
1647 /* A record which has any BLKmode members must itself be
1648 BLKmode; it can't go in a register. Unless the member is
1649 BLKmode only because it isn't aligned. */
1650 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
1652 if (TREE_CODE (field) != FIELD_DECL)
1655 if (TREE_CODE (TREE_TYPE (field)) == ERROR_MARK
1656 || (TYPE_MODE (TREE_TYPE (field)) == BLKmode
1657 && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))
1658 && !(TYPE_SIZE (TREE_TYPE (field)) != 0
1659 && integer_zerop (TYPE_SIZE (TREE_TYPE (field)))))
1660 || ! host_integerp (bit_position (field), 1)
1661 || DECL_SIZE (field) == 0
1662 || ! host_integerp (DECL_SIZE (field), 1))
1665 /* If this field is the whole struct, remember its mode so
1666 that, say, we can put a double in a class into a DF
1667 register instead of forcing it to live in the stack. */
1668 if (simple_cst_equal (TYPE_SIZE (type), DECL_SIZE (field)))
1669 mode = DECL_MODE (field);
1671 #ifdef MEMBER_TYPE_FORCES_BLK
1672 /* With some targets, eg. c4x, it is sub-optimal
1673 to access an aligned BLKmode structure as a scalar. */
1675 if (MEMBER_TYPE_FORCES_BLK (field, mode))
1677 #endif /* MEMBER_TYPE_FORCES_BLK */
1680 /* If we only have one real field; use its mode if that mode's size
1681 matches the type's size. This only applies to RECORD_TYPE. This
1682 does not apply to unions. */
1683 if (TREE_CODE (type) == RECORD_TYPE && mode != VOIDmode
1684 && host_integerp (TYPE_SIZE (type), 1)
1685 && GET_MODE_BITSIZE (mode) == TREE_INT_CST_LOW (TYPE_SIZE (type)))
1686 SET_TYPE_MODE (type, mode);
1688 SET_TYPE_MODE (type, mode_for_size_tree (TYPE_SIZE (type), MODE_INT, 1));
1690 /* If structure's known alignment is less than what the scalar
1691 mode would need, and it matters, then stick with BLKmode. */
1692 if (TYPE_MODE (type) != BLKmode
1694 && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
1695 || TYPE_ALIGN (type) >= GET_MODE_ALIGNMENT (TYPE_MODE (type))))
1697 /* If this is the only reason this type is BLKmode, then
1698 don't force containing types to be BLKmode. */
1699 TYPE_NO_FORCE_BLK (type) = 1;
1700 SET_TYPE_MODE (type, BLKmode);
1704 /* Compute TYPE_SIZE and TYPE_ALIGN for TYPE, once it has been laid
1708 finalize_type_size (tree type)
1710 /* Normally, use the alignment corresponding to the mode chosen.
1711 However, where strict alignment is not required, avoid
1712 over-aligning structures, since most compilers do not do this
1715 if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
1716 && (STRICT_ALIGNMENT
1717 || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
1718 && TREE_CODE (type) != QUAL_UNION_TYPE
1719 && TREE_CODE (type) != ARRAY_TYPE)))
1721 unsigned mode_align = GET_MODE_ALIGNMENT (TYPE_MODE (type));
1723 /* Don't override a larger alignment requirement coming from a user
1724 alignment of one of the fields. */
1725 if (mode_align >= TYPE_ALIGN (type))
1727 TYPE_ALIGN (type) = mode_align;
1728 TYPE_USER_ALIGN (type) = 0;
1732 /* Do machine-dependent extra alignment. */
1733 #ifdef ROUND_TYPE_ALIGN
1735 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (type), BITS_PER_UNIT);
1738 /* If we failed to find a simple way to calculate the unit size
1739 of the type, find it by division. */
1740 if (TYPE_SIZE_UNIT (type) == 0 && TYPE_SIZE (type) != 0)
1741 /* TYPE_SIZE (type) is computed in bitsizetype. After the division, the
1742 result will fit in sizetype. We will get more efficient code using
1743 sizetype, so we force a conversion. */
1744 TYPE_SIZE_UNIT (type)
1745 = fold_convert (sizetype,
1746 size_binop (FLOOR_DIV_EXPR, TYPE_SIZE (type),
1747 bitsize_unit_node));
1749 if (TYPE_SIZE (type) != 0)
1751 TYPE_SIZE (type) = round_up (TYPE_SIZE (type), TYPE_ALIGN (type));
1752 TYPE_SIZE_UNIT (type)
1753 = round_up (TYPE_SIZE_UNIT (type), TYPE_ALIGN_UNIT (type));
1756 /* Evaluate nonconstant sizes only once, either now or as soon as safe. */
1757 if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
1758 TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
1759 if (TYPE_SIZE_UNIT (type) != 0
1760 && TREE_CODE (TYPE_SIZE_UNIT (type)) != INTEGER_CST)
1761 TYPE_SIZE_UNIT (type) = variable_size (TYPE_SIZE_UNIT (type));
1763 /* Also layout any other variants of the type. */
1764 if (TYPE_NEXT_VARIANT (type)
1765 || type != TYPE_MAIN_VARIANT (type))
1768 /* Record layout info of this variant. */
1769 tree size = TYPE_SIZE (type);
1770 tree size_unit = TYPE_SIZE_UNIT (type);
1771 unsigned int align = TYPE_ALIGN (type);
1772 unsigned int user_align = TYPE_USER_ALIGN (type);
1773 enum machine_mode mode = TYPE_MODE (type);
1775 /* Copy it into all variants. */
1776 for (variant = TYPE_MAIN_VARIANT (type);
1778 variant = TYPE_NEXT_VARIANT (variant))
1780 TYPE_SIZE (variant) = size;
1781 TYPE_SIZE_UNIT (variant) = size_unit;
1782 TYPE_ALIGN (variant) = align;
1783 TYPE_USER_ALIGN (variant) = user_align;
1784 SET_TYPE_MODE (variant, mode);
1789 /* Do all of the work required to layout the type indicated by RLI,
1790 once the fields have been laid out. This function will call `free'
1791 for RLI, unless FREE_P is false. Passing a value other than false
1792 for FREE_P is bad practice; this option only exists to support the
1796 finish_record_layout (record_layout_info rli, int free_p)
1800 /* Compute the final size. */
1801 finalize_record_size (rli);
1803 /* Compute the TYPE_MODE for the record. */
1804 compute_record_mode (rli->t);
1806 /* Perform any last tweaks to the TYPE_SIZE, etc. */
1807 finalize_type_size (rli->t);
1809 /* Propagate TYPE_PACKED to variants. With C++ templates,
1810 handle_packed_attribute is too early to do this. */
1811 for (variant = TYPE_NEXT_VARIANT (rli->t); variant;
1812 variant = TYPE_NEXT_VARIANT (variant))
1813 TYPE_PACKED (variant) = TYPE_PACKED (rli->t);
1815 /* Lay out any static members. This is done now because their type
1816 may use the record's type. */
1817 while (!VEC_empty (tree, rli->pending_statics))
1818 layout_decl (VEC_pop (tree, rli->pending_statics), 0);
1823 VEC_free (tree, gc, rli->pending_statics);
1829 /* Finish processing a builtin RECORD_TYPE type TYPE. It's name is
1830 NAME, its fields are chained in reverse on FIELDS.
1832 If ALIGN_TYPE is non-null, it is given the same alignment as
1836 finish_builtin_struct (tree type, const char *name, tree fields,
1841 for (tail = NULL_TREE; fields; tail = fields, fields = next)
1843 DECL_FIELD_CONTEXT (fields) = type;
1844 next = DECL_CHAIN (fields);
1845 DECL_CHAIN (fields) = tail;
1847 TYPE_FIELDS (type) = tail;
1851 TYPE_ALIGN (type) = TYPE_ALIGN (align_type);
1852 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (align_type);
1856 #if 0 /* not yet, should get fixed properly later */
1857 TYPE_NAME (type) = make_type_decl (get_identifier (name), type);
1859 TYPE_NAME (type) = build_decl (BUILTINS_LOCATION,
1860 TYPE_DECL, get_identifier (name), type);
1862 TYPE_STUB_DECL (type) = TYPE_NAME (type);
1863 layout_decl (TYPE_NAME (type), 0);
1866 /* Calculate the mode, size, and alignment for TYPE.
1867 For an array type, calculate the element separation as well.
1868 Record TYPE on the chain of permanent or temporary types
1869 so that dbxout will find out about it.
1871 TYPE_SIZE of a type is nonzero if the type has been laid out already.
1872 layout_type does nothing on such a type.
1874 If the type is incomplete, its TYPE_SIZE remains zero. */
1877 layout_type (tree type)
1881 if (type == error_mark_node)
1884 /* Do nothing if type has been laid out before. */
1885 if (TYPE_SIZE (type))
1888 switch (TREE_CODE (type))
1891 /* This kind of type is the responsibility
1892 of the language-specific code. */
1895 case BOOLEAN_TYPE: /* Used for Java, Pascal, and Chill. */
1896 if (TYPE_PRECISION (type) == 0)
1897 TYPE_PRECISION (type) = 1; /* default to one byte/boolean. */
1899 /* ... fall through ... */
1903 if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
1904 && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
1905 TYPE_UNSIGNED (type) = 1;
1907 SET_TYPE_MODE (type,
1908 smallest_mode_for_size (TYPE_PRECISION (type), MODE_INT));
1909 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1910 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1914 SET_TYPE_MODE (type,
1915 mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0));
1916 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1917 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1920 case FIXED_POINT_TYPE:
1921 /* TYPE_MODE (type) has been set already. */
1922 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1923 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1927 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1928 SET_TYPE_MODE (type,
1929 mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
1930 (TREE_CODE (TREE_TYPE (type)) == REAL_TYPE
1931 ? MODE_COMPLEX_FLOAT : MODE_COMPLEX_INT),
1933 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
1934 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (TYPE_MODE (type)));
1939 int nunits = TYPE_VECTOR_SUBPARTS (type);
1940 tree innertype = TREE_TYPE (type);
1942 gcc_assert (!(nunits & (nunits - 1)));
1944 /* Find an appropriate mode for the vector type. */
1945 if (TYPE_MODE (type) == VOIDmode)
1946 SET_TYPE_MODE (type,
1947 mode_for_vector (TYPE_MODE (innertype), nunits));
1949 TYPE_SATURATING (type) = TYPE_SATURATING (TREE_TYPE (type));
1950 TYPE_UNSIGNED (type) = TYPE_UNSIGNED (TREE_TYPE (type));
1951 TYPE_SIZE_UNIT (type) = int_const_binop (MULT_EXPR,
1952 TYPE_SIZE_UNIT (innertype),
1953 size_int (nunits), 0);
1954 TYPE_SIZE (type) = int_const_binop (MULT_EXPR, TYPE_SIZE (innertype),
1955 bitsize_int (nunits), 0);
1957 /* Always naturally align vectors. This prevents ABI changes
1958 depending on whether or not native vector modes are supported. */
1959 TYPE_ALIGN (type) = tree_low_cst (TYPE_SIZE (type), 0);
1964 /* This is an incomplete type and so doesn't have a size. */
1965 TYPE_ALIGN (type) = 1;
1966 TYPE_USER_ALIGN (type) = 0;
1967 SET_TYPE_MODE (type, VOIDmode);
1971 TYPE_SIZE (type) = bitsize_int (POINTER_SIZE);
1972 TYPE_SIZE_UNIT (type) = size_int (POINTER_SIZE / BITS_PER_UNIT);
1973 /* A pointer might be MODE_PARTIAL_INT,
1974 but ptrdiff_t must be integral. */
1975 SET_TYPE_MODE (type, mode_for_size (POINTER_SIZE, MODE_INT, 0));
1976 TYPE_PRECISION (type) = POINTER_SIZE;
1981 /* It's hard to see what the mode and size of a function ought to
1982 be, but we do know the alignment is FUNCTION_BOUNDARY, so
1983 make it consistent with that. */
1984 SET_TYPE_MODE (type, mode_for_size (FUNCTION_BOUNDARY, MODE_INT, 0));
1985 TYPE_SIZE (type) = bitsize_int (FUNCTION_BOUNDARY);
1986 TYPE_SIZE_UNIT (type) = size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
1990 case REFERENCE_TYPE:
1992 enum machine_mode mode = TYPE_MODE (type);
1993 if (TREE_CODE (type) == REFERENCE_TYPE && reference_types_internal)
1995 addr_space_t as = TYPE_ADDR_SPACE (TREE_TYPE (type));
1996 mode = targetm.addr_space.address_mode (as);
1999 TYPE_SIZE (type) = bitsize_int (GET_MODE_BITSIZE (mode));
2000 TYPE_SIZE_UNIT (type) = size_int (GET_MODE_SIZE (mode));
2001 TYPE_UNSIGNED (type) = 1;
2002 TYPE_PRECISION (type) = GET_MODE_BITSIZE (mode);
2008 tree index = TYPE_DOMAIN (type);
2009 tree element = TREE_TYPE (type);
2011 build_pointer_type (element);
2013 /* We need to know both bounds in order to compute the size. */
2014 if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
2015 && TYPE_SIZE (element))
2017 tree ub = TYPE_MAX_VALUE (index);
2018 tree lb = TYPE_MIN_VALUE (index);
2019 tree element_size = TYPE_SIZE (element);
2022 /* Make sure that an array of zero-sized element is zero-sized
2023 regardless of its extent. */
2024 if (integer_zerop (element_size))
2025 length = size_zero_node;
2027 /* The computation should happen in the original type so
2028 that (possible) negative values are handled appropriately. */
2031 = fold_convert (sizetype,
2032 fold_build2 (PLUS_EXPR, TREE_TYPE (lb),
2033 build_int_cst (TREE_TYPE (lb), 1),
2034 fold_build2 (MINUS_EXPR,
2038 TYPE_SIZE (type) = size_binop (MULT_EXPR, element_size,
2039 fold_convert (bitsizetype,
2042 /* If we know the size of the element, calculate the total size
2043 directly, rather than do some division thing below. This
2044 optimization helps Fortran assumed-size arrays (where the
2045 size of the array is determined at runtime) substantially. */
2046 if (TYPE_SIZE_UNIT (element))
2047 TYPE_SIZE_UNIT (type)
2048 = size_binop (MULT_EXPR, TYPE_SIZE_UNIT (element), length);
2051 /* Now round the alignment and size,
2052 using machine-dependent criteria if any. */
2054 #ifdef ROUND_TYPE_ALIGN
2056 = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
2058 TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
2060 TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (element);
2061 SET_TYPE_MODE (type, BLKmode);
2062 if (TYPE_SIZE (type) != 0
2063 #ifdef MEMBER_TYPE_FORCES_BLK
2064 && ! MEMBER_TYPE_FORCES_BLK (type, VOIDmode)
2066 /* BLKmode elements force BLKmode aggregate;
2067 else extract/store fields may lose. */
2068 && (TYPE_MODE (TREE_TYPE (type)) != BLKmode
2069 || TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
2071 SET_TYPE_MODE (type, mode_for_array (TREE_TYPE (type),
2073 if (TYPE_MODE (type) != BLKmode
2074 && STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
2075 && TYPE_ALIGN (type) < GET_MODE_ALIGNMENT (TYPE_MODE (type)))
2077 TYPE_NO_FORCE_BLK (type) = 1;
2078 SET_TYPE_MODE (type, BLKmode);
2081 /* When the element size is constant, check that it is at least as
2082 large as the element alignment. */
2083 if (TYPE_SIZE_UNIT (element)
2084 && TREE_CODE (TYPE_SIZE_UNIT (element)) == INTEGER_CST
2085 /* If TYPE_SIZE_UNIT overflowed, then it is certainly larger than
2087 && !TREE_OVERFLOW (TYPE_SIZE_UNIT (element))
2088 && !integer_zerop (TYPE_SIZE_UNIT (element))
2089 && compare_tree_int (TYPE_SIZE_UNIT (element),
2090 TYPE_ALIGN_UNIT (element)) < 0)
2091 error ("alignment of array elements is greater than element size");
2097 case QUAL_UNION_TYPE:
2100 record_layout_info rli;
2102 /* Initialize the layout information. */
2103 rli = start_record_layout (type);
2105 /* If this is a QUAL_UNION_TYPE, we want to process the fields
2106 in the reverse order in building the COND_EXPR that denotes
2107 its size. We reverse them again later. */
2108 if (TREE_CODE (type) == QUAL_UNION_TYPE)
2109 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
2111 /* Place all the fields. */
2112 for (field = TYPE_FIELDS (type); field; field = DECL_CHAIN (field))
2113 place_field (rli, field);
2115 if (TREE_CODE (type) == QUAL_UNION_TYPE)
2116 TYPE_FIELDS (type) = nreverse (TYPE_FIELDS (type));
2118 /* Finish laying out the record. */
2119 finish_record_layout (rli, /*free_p=*/true);
2127 /* Compute the final TYPE_SIZE, TYPE_ALIGN, etc. for TYPE. For
2128 records and unions, finish_record_layout already called this
2130 if (TREE_CODE (type) != RECORD_TYPE
2131 && TREE_CODE (type) != UNION_TYPE
2132 && TREE_CODE (type) != QUAL_UNION_TYPE)
2133 finalize_type_size (type);
2135 /* We should never see alias sets on incomplete aggregates. And we
2136 should not call layout_type on not incomplete aggregates. */
2137 if (AGGREGATE_TYPE_P (type))
2138 gcc_assert (!TYPE_ALIAS_SET_KNOWN_P (type));
2141 /* Vector types need to re-check the target flags each time we report
2142 the machine mode. We need to do this because attribute target can
2143 change the result of vector_mode_supported_p and have_regs_of_mode
2144 on a per-function basis. Thus the TYPE_MODE of a VECTOR_TYPE can
2145 change on a per-function basis. */
2146 /* ??? Possibly a better solution is to run through all the types
2147 referenced by a function and re-compute the TYPE_MODE once, rather
2148 than make the TYPE_MODE macro call a function. */
2151 vector_type_mode (const_tree t)
2153 enum machine_mode mode;
2155 gcc_assert (TREE_CODE (t) == VECTOR_TYPE);
2157 mode = t->type.mode;
2158 if (VECTOR_MODE_P (mode)
2159 && (!targetm.vector_mode_supported_p (mode)
2160 || !have_regs_of_mode[mode]))
2162 enum machine_mode innermode = TREE_TYPE (t)->type.mode;
2164 /* For integers, try mapping it to a same-sized scalar mode. */
2165 if (GET_MODE_CLASS (innermode) == MODE_INT)
2167 mode = mode_for_size (TYPE_VECTOR_SUBPARTS (t)
2168 * GET_MODE_BITSIZE (innermode), MODE_INT, 0);
2170 if (mode != VOIDmode && have_regs_of_mode[mode])
2180 /* Create and return a type for signed integers of PRECISION bits. */
2183 make_signed_type (int precision)
2185 tree type = make_node (INTEGER_TYPE);
2187 TYPE_PRECISION (type) = precision;
2189 fixup_signed_type (type);
2193 /* Create and return a type for unsigned integers of PRECISION bits. */
2196 make_unsigned_type (int precision)
2198 tree type = make_node (INTEGER_TYPE);
2200 TYPE_PRECISION (type) = precision;
2202 fixup_unsigned_type (type);
2206 /* Create and return a type for fract of PRECISION bits, UNSIGNEDP,
2210 make_fract_type (int precision, int unsignedp, int satp)
2212 tree type = make_node (FIXED_POINT_TYPE);
2214 TYPE_PRECISION (type) = precision;
2217 TYPE_SATURATING (type) = 1;
2219 /* Lay out the type: set its alignment, size, etc. */
2222 TYPE_UNSIGNED (type) = 1;
2223 SET_TYPE_MODE (type, mode_for_size (precision, MODE_UFRACT, 0));
2226 SET_TYPE_MODE (type, mode_for_size (precision, MODE_FRACT, 0));
2232 /* Create and return a type for accum of PRECISION bits, UNSIGNEDP,
2236 make_accum_type (int precision, int unsignedp, int satp)
2238 tree type = make_node (FIXED_POINT_TYPE);
2240 TYPE_PRECISION (type) = precision;
2243 TYPE_SATURATING (type) = 1;
2245 /* Lay out the type: set its alignment, size, etc. */
2248 TYPE_UNSIGNED (type) = 1;
2249 SET_TYPE_MODE (type, mode_for_size (precision, MODE_UACCUM, 0));
2252 SET_TYPE_MODE (type, mode_for_size (precision, MODE_ACCUM, 0));
2258 /* Initialize sizetype and bitsizetype to a reasonable and temporary
2259 value to enable integer types to be created. */
2262 initialize_sizetypes (void)
2264 tree t = make_node (INTEGER_TYPE);
2265 int precision = GET_MODE_BITSIZE (SImode);
2267 SET_TYPE_MODE (t, SImode);
2268 TYPE_ALIGN (t) = GET_MODE_ALIGNMENT (SImode);
2269 TYPE_IS_SIZETYPE (t) = 1;
2270 TYPE_UNSIGNED (t) = 1;
2271 TYPE_SIZE (t) = build_int_cst (t, precision);
2272 TYPE_SIZE_UNIT (t) = build_int_cst (t, GET_MODE_SIZE (SImode));
2273 TYPE_PRECISION (t) = precision;
2275 set_min_and_max_values_for_integral_type (t, precision,
2276 /*is_unsigned=*/true);
2279 bitsizetype = build_distinct_type_copy (t);
2282 /* Make sizetype a version of TYPE, and initialize *sizetype accordingly.
2283 We do this by overwriting the stub sizetype and bitsizetype nodes created
2284 by initialize_sizetypes. This makes sure that (a) anything stubby about
2285 them no longer exists and (b) any INTEGER_CSTs created with such a type,
2289 set_sizetype (tree type)
2292 int oprecision = TYPE_PRECISION (type);
2293 /* The *bitsizetype types use a precision that avoids overflows when
2294 calculating signed sizes / offsets in bits. However, when
2295 cross-compiling from a 32 bit to a 64 bit host, we are limited to 64 bit
2298 = MIN (oprecision + BITS_PER_UNIT_LOG + 1, MAX_FIXED_MODE_SIZE);
2300 = GET_MODE_PRECISION (smallest_mode_for_size (precision, MODE_INT));
2301 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2302 precision = HOST_BITS_PER_WIDE_INT * 2;
2304 /* sizetype must be an unsigned type. */
2305 gcc_assert (TYPE_UNSIGNED (type));
2307 t = build_distinct_type_copy (type);
2308 /* We want to use sizetype's cache, as we will be replacing that type. */
2309 TYPE_CACHED_VALUES (t) = TYPE_CACHED_VALUES (sizetype);
2310 TYPE_CACHED_VALUES_P (t) = TYPE_CACHED_VALUES_P (sizetype);
2311 TYPE_UID (t) = TYPE_UID (sizetype);
2312 TYPE_IS_SIZETYPE (t) = 1;
2314 /* Replace our original stub sizetype. */
2315 memcpy (sizetype, t, tree_size (sizetype));
2316 TYPE_MAIN_VARIANT (sizetype) = sizetype;
2317 TYPE_CANONICAL (sizetype) = sizetype;
2319 /* sizetype is unsigned but we need to fix TYPE_MAX_VALUE so that it is
2320 sign-extended in a way consistent with force_fit_type. */
2321 max = TYPE_MAX_VALUE (sizetype);
2322 TYPE_MAX_VALUE (sizetype)
2323 = double_int_to_tree (sizetype, tree_to_double_int (max));
2325 t = make_node (INTEGER_TYPE);
2326 TYPE_NAME (t) = get_identifier ("bit_size_type");
2327 /* We want to use bitsizetype's cache, as we will be replacing that type. */
2328 TYPE_CACHED_VALUES (t) = TYPE_CACHED_VALUES (bitsizetype);
2329 TYPE_CACHED_VALUES_P (t) = TYPE_CACHED_VALUES_P (bitsizetype);
2330 TYPE_PRECISION (t) = precision;
2331 TYPE_UID (t) = TYPE_UID (bitsizetype);
2332 TYPE_IS_SIZETYPE (t) = 1;
2334 /* Replace our original stub bitsizetype. */
2335 memcpy (bitsizetype, t, tree_size (bitsizetype));
2336 TYPE_MAIN_VARIANT (bitsizetype) = bitsizetype;
2337 TYPE_CANONICAL (bitsizetype) = bitsizetype;
2339 fixup_unsigned_type (bitsizetype);
2341 /* Create the signed variants of *sizetype. */
2342 ssizetype = make_signed_type (oprecision);
2343 TYPE_IS_SIZETYPE (ssizetype) = 1;
2344 sbitsizetype = make_signed_type (precision);
2345 TYPE_IS_SIZETYPE (sbitsizetype) = 1;
2348 /* TYPE is an integral type, i.e., an INTEGRAL_TYPE, ENUMERAL_TYPE
2349 or BOOLEAN_TYPE. Set TYPE_MIN_VALUE and TYPE_MAX_VALUE
2350 for TYPE, based on the PRECISION and whether or not the TYPE
2351 IS_UNSIGNED. PRECISION need not correspond to a width supported
2352 natively by the hardware; for example, on a machine with 8-bit,
2353 16-bit, and 32-bit register modes, PRECISION might be 7, 23, or
2357 set_min_and_max_values_for_integral_type (tree type,
2366 min_value = build_int_cst (type, 0);
2368 = build_int_cst_wide (type, precision - HOST_BITS_PER_WIDE_INT >= 0
2370 : ((HOST_WIDE_INT) 1 << precision) - 1,
2371 precision - HOST_BITS_PER_WIDE_INT > 0
2372 ? ((unsigned HOST_WIDE_INT) ~0
2373 >> (HOST_BITS_PER_WIDE_INT
2374 - (precision - HOST_BITS_PER_WIDE_INT)))
2380 = build_int_cst_wide (type,
2381 (precision - HOST_BITS_PER_WIDE_INT > 0
2383 : (HOST_WIDE_INT) (-1) << (precision - 1)),
2384 (((HOST_WIDE_INT) (-1)
2385 << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2386 ? precision - HOST_BITS_PER_WIDE_INT - 1
2389 = build_int_cst_wide (type,
2390 (precision - HOST_BITS_PER_WIDE_INT > 0
2392 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
2393 (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
2394 ? (((HOST_WIDE_INT) 1
2395 << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
2399 TYPE_MIN_VALUE (type) = min_value;
2400 TYPE_MAX_VALUE (type) = max_value;
2403 /* Set the extreme values of TYPE based on its precision in bits,
2404 then lay it out. Used when make_signed_type won't do
2405 because the tree code is not INTEGER_TYPE.
2406 E.g. for Pascal, when the -fsigned-char option is given. */
2409 fixup_signed_type (tree type)
2411 int precision = TYPE_PRECISION (type);
2413 /* We can not represent properly constants greater then
2414 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2415 as they are used by i386 vector extensions and friends. */
2416 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2417 precision = HOST_BITS_PER_WIDE_INT * 2;
2419 set_min_and_max_values_for_integral_type (type, precision,
2420 /*is_unsigned=*/false);
2422 /* Lay out the type: set its alignment, size, etc. */
2426 /* Set the extreme values of TYPE based on its precision in bits,
2427 then lay it out. This is used both in `make_unsigned_type'
2428 and for enumeral types. */
2431 fixup_unsigned_type (tree type)
2433 int precision = TYPE_PRECISION (type);
2435 /* We can not represent properly constants greater then
2436 2 * HOST_BITS_PER_WIDE_INT, still we need the types
2437 as they are used by i386 vector extensions and friends. */
2438 if (precision > HOST_BITS_PER_WIDE_INT * 2)
2439 precision = HOST_BITS_PER_WIDE_INT * 2;
2441 TYPE_UNSIGNED (type) = 1;
2443 set_min_and_max_values_for_integral_type (type, precision,
2444 /*is_unsigned=*/true);
2446 /* Lay out the type: set its alignment, size, etc. */
2450 /* Find the best machine mode to use when referencing a bit field of length
2451 BITSIZE bits starting at BITPOS.
2453 The underlying object is known to be aligned to a boundary of ALIGN bits.
2454 If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
2455 larger than LARGEST_MODE (usually SImode).
2457 If no mode meets all these conditions, we return VOIDmode.
2459 If VOLATILEP is false and SLOW_BYTE_ACCESS is false, we return the
2460 smallest mode meeting these conditions.
2462 If VOLATILEP is false and SLOW_BYTE_ACCESS is true, we return the
2463 largest mode (but a mode no wider than UNITS_PER_WORD) that meets
2466 If VOLATILEP is true the narrow_volatile_bitfields target hook is used to
2467 decide which of the above modes should be used. */
2470 get_best_mode (int bitsize, int bitpos, unsigned int align,
2471 enum machine_mode largest_mode, int volatilep)
2473 enum machine_mode mode;
2474 unsigned int unit = 0;
2476 /* Find the narrowest integer mode that contains the bit field. */
2477 for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
2478 mode = GET_MODE_WIDER_MODE (mode))
2480 unit = GET_MODE_BITSIZE (mode);
2481 if ((bitpos % unit) + bitsize <= unit)
2485 if (mode == VOIDmode
2486 /* It is tempting to omit the following line
2487 if STRICT_ALIGNMENT is true.
2488 But that is incorrect, since if the bitfield uses part of 3 bytes
2489 and we use a 4-byte mode, we could get a spurious segv
2490 if the extra 4th byte is past the end of memory.
2491 (Though at least one Unix compiler ignores this problem:
2492 that on the Sequent 386 machine. */
2493 || MIN (unit, BIGGEST_ALIGNMENT) > align
2494 || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
2497 if ((SLOW_BYTE_ACCESS && ! volatilep)
2498 || (volatilep && !targetm.narrow_volatile_bitfield ()))
2500 enum machine_mode wide_mode = VOIDmode, tmode;
2502 for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
2503 tmode = GET_MODE_WIDER_MODE (tmode))
2505 unit = GET_MODE_BITSIZE (tmode);
2506 if (bitpos / unit == (bitpos + bitsize - 1) / unit
2507 && unit <= BITS_PER_WORD
2508 && unit <= MIN (align, BIGGEST_ALIGNMENT)
2509 && (largest_mode == VOIDmode
2510 || unit <= GET_MODE_BITSIZE (largest_mode)))
2514 if (wide_mode != VOIDmode)
2521 /* Gets minimal and maximal values for MODE (signed or unsigned depending on
2522 SIGN). The returned constants are made to be usable in TARGET_MODE. */
2525 get_mode_bounds (enum machine_mode mode, int sign,
2526 enum machine_mode target_mode,
2527 rtx *mmin, rtx *mmax)
2529 unsigned size = GET_MODE_BITSIZE (mode);
2530 unsigned HOST_WIDE_INT min_val, max_val;
2532 gcc_assert (size <= HOST_BITS_PER_WIDE_INT);
2536 min_val = -((unsigned HOST_WIDE_INT) 1 << (size - 1));
2537 max_val = ((unsigned HOST_WIDE_INT) 1 << (size - 1)) - 1;
2542 max_val = ((unsigned HOST_WIDE_INT) 1 << (size - 1) << 1) - 1;
2545 *mmin = gen_int_mode (min_val, target_mode);
2546 *mmax = gen_int_mode (max_val, target_mode);
2549 #include "gt-stor-layout.h"