fe7dee4700
GCC-2.6.1 COMES TO FREEBSD-current ---------------------------------- Everybody needs to 'make world'. Oakland, Nov 2nd 1994. In a surprise move this sunny afternoon, the release- engineer for the slightly delayed FreeBSD-2.0, Poul-Henning Kamp (28), decided to pull in the new version 2.6.1 of the GNU C-compiler. The new version of the compiler was release today at noon, and hardly 9 hours later it was committed into the FreeBSD-current source-repository. "It's is simply because we have had too much trouble with the version 2.6.0 of the compiler" Poul-Henning told the FreeBSD-Gazette, "we took a gamble when we decided to use that as our compiler for the 2.0 release, but it seems to pay of in the end now" he concludes. The move has not been discussed on the "core" list at all, and will come as a surprise for most Poul-Hennings peers. "I have only discussed it with Jordan [J. K. Hubbard, the FreeBSD's resident humourist], and we agreed that we needed to do it, so ... I did it!". After a breath he added with a grin: "My email will probably get an all time 'disk-full' now!". This will bring quite a flag-day to the FreeBSD developers, the patch-file is almost 1.4 Megabyte, and they will have to run "make world" to get entirely -current again. "Too bad, but we just had to do this." Was the only comment from Poul-Henning to these problems. When asked how this move would impact the 2.0 release-date, Poul-Hennings face grew dark, he mumbled some very Danish words while he moved his fingers in strange geometrical patterns. Immediately something ecclipsed the Sun, a minor tremor shook the buildings, and the temperature fell significantly. We decided not to pursure the question. ----------- JOB-SECTION ----------- Are you a dedicated GCC-hacker ? We BADLY need somebody to look at the 'freebsd' OS in gcc, sanitize it and carry the patches back to the GNU people. In particular, we need to get out of the "i386-only" spot we are in now. I have the stuff to take a gnu-dist into bmake-form, and will do that part. Please apply to phk@freebsd.org No Novice Need Apply.
1206 lines
37 KiB
C
1206 lines
37 KiB
C
/* C-compiler utilities for types and variables storage layout
|
||
Copyright (C) 1987, 1988, 1992, 1993, 1994 Free Software Foundation, Inc.
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This file is part of GNU CC.
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GNU CC is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
|
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any later version.
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GNU CC is distributed in the hope that it will be useful,
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||
but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
GNU General Public License for more details.
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||
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You should have received a copy of the GNU General Public License
|
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along with GNU CC; see the file COPYING. If not, write to
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the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
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#include "config.h"
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#include <stdio.h>
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#include "tree.h"
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#include "function.h"
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#define CEIL(x,y) (((x) + (y) - 1) / (y))
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||
/* Data type for the expressions representing sizes of data types.
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It is the first integer type laid out.
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In C, this is int. */
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tree sizetype;
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/* An integer constant with value 0 whose type is sizetype. */
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tree size_zero_node;
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/* An integer constant with value 1 whose type is sizetype. */
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tree size_one_node;
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/* If nonzero, this is an upper limit on alignment of structure fields.
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The value is measured in bits. */
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int maximum_field_alignment;
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/* If non-zero, the alignment of a bitsting or (power-)set value, in bits.
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May be overridden by front-ends. */
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int set_alignment = 0;
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#define GET_MODE_ALIGNMENT(MODE) \
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MIN (BIGGEST_ALIGNMENT, \
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MAX (1, (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT)))
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static enum machine_mode smallest_mode_for_size PROTO((unsigned int,
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enum mode_class));
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static tree layout_record PROTO((tree));
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static void layout_union PROTO((tree));
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/* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */
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static tree pending_sizes;
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/* Nonzero means cannot safely call expand_expr now,
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so put variable sizes onto `pending_sizes' instead. */
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int immediate_size_expand;
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tree
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get_pending_sizes ()
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{
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tree chain = pending_sizes;
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tree t;
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/* Put each SAVE_EXPR into the current function. */
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for (t = chain; t; t = TREE_CHAIN (t))
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SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl;
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pending_sizes = 0;
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return chain;
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}
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/* Given a size SIZE that isn't constant, return a SAVE_EXPR
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to serve as the actual size-expression for a type or decl. */
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tree
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variable_size (size)
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tree size;
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{
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/* If the language-processor is to take responsibility for variable-sized
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items (e.g., languages which have elaboration procedures like Ada),
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just return SIZE unchanged. Likewise for self-referential sizes. */
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if (global_bindings_p () < 0 || contains_placeholder_p (size))
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return size;
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size = save_expr (size);
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if (global_bindings_p ())
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{
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if (TREE_CONSTANT (size))
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error ("type size can't be explicitly evaluated");
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else
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error ("variable-size type declared outside of any function");
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return size_int (1);
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}
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if (immediate_size_expand)
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/* NULL_RTX is not defined; neither is the rtx type.
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Also, we would like to pass const0_rtx here, but don't have it. */
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expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0),
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VOIDmode, 0);
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else
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pending_sizes = tree_cons (NULL_TREE, size, pending_sizes);
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return size;
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}
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#ifndef MAX_FIXED_MODE_SIZE
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#define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode)
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#endif
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/* Return the machine mode to use for a nonscalar of SIZE bits.
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The mode must be in class CLASS, and have exactly that many bits.
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If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not
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be used. */
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enum machine_mode
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mode_for_size (size, class, limit)
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unsigned int size;
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enum mode_class class;
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||
int limit;
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||
{
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register enum machine_mode mode;
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if (limit && size > MAX_FIXED_MODE_SIZE)
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return BLKmode;
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|
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/* Get the first mode which has this size, in the specified class. */
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for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
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mode = GET_MODE_WIDER_MODE (mode))
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if (GET_MODE_BITSIZE (mode) == size)
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return mode;
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||
return BLKmode;
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}
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/* Similar, but never return BLKmode; return the narrowest mode that
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contains at least the requested number of bits. */
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static enum machine_mode
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||
smallest_mode_for_size (size, class)
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unsigned int size;
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enum mode_class class;
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||
{
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||
register enum machine_mode mode;
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|
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/* Get the first mode which has at least this size, in the
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||
specified class. */
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||
for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode;
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mode = GET_MODE_WIDER_MODE (mode))
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if (GET_MODE_BITSIZE (mode) >= size)
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return mode;
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abort ();
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}
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||
/* Return the value of VALUE, rounded up to a multiple of DIVISOR. */
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tree
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round_up (value, divisor)
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tree value;
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int divisor;
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{
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return size_binop (MULT_EXPR,
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size_binop (CEIL_DIV_EXPR, value, size_int (divisor)),
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size_int (divisor));
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}
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/* Set the size, mode and alignment of a ..._DECL node.
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TYPE_DECL does need this for C++.
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Note that LABEL_DECL and CONST_DECL nodes do not need this,
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and FUNCTION_DECL nodes have them set up in a special (and simple) way.
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Don't call layout_decl for them.
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KNOWN_ALIGN is the amount of alignment we can assume this
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decl has with no special effort. It is relevant only for FIELD_DECLs
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and depends on the previous fields.
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All that matters about KNOWN_ALIGN is which powers of 2 divide it.
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If KNOWN_ALIGN is 0, it means, "as much alignment as you like":
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the record will be aligned to suit. */
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void
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layout_decl (decl, known_align)
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tree decl;
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unsigned known_align;
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{
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register tree type = TREE_TYPE (decl);
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register enum tree_code code = TREE_CODE (decl);
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int spec_size = DECL_FIELD_SIZE (decl);
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if (code == CONST_DECL)
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return;
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if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL
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&& code != FIELD_DECL && code != TYPE_DECL)
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abort ();
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if (type == error_mark_node)
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{
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type = void_type_node;
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spec_size = 0;
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}
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/* Usually the size and mode come from the data type without change. */
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DECL_MODE (decl) = TYPE_MODE (type);
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TREE_UNSIGNED (decl) = TREE_UNSIGNED (type);
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if (DECL_SIZE (decl) == 0)
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DECL_SIZE (decl) = TYPE_SIZE (type);
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if (code == FIELD_DECL && DECL_BIT_FIELD (decl))
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{
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/* This is a bit-field. We don't know how to handle
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them except for integral types, and front ends should
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never generate them otherwise. */
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if (! INTEGRAL_TYPE_P (type))
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abort ();
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if (spec_size == 0 && DECL_NAME (decl) != 0)
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abort ();
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/* Size is specified number of bits. */
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DECL_SIZE (decl) = size_int (spec_size);
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}
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/* Force alignment required for the data type.
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But if the decl itself wants greater alignment, don't override that.
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Likewise, if the decl is packed, don't override it. */
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else if (DECL_ALIGN (decl) == 0
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|| (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl)))
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DECL_ALIGN (decl) = TYPE_ALIGN (type);
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/* See if we can use an ordinary integer mode for a bit-field. */
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/* Conditions are: a fixed size that is correct for another mode
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and occupying a complete byte or bytes on proper boundary. */
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if (code == FIELD_DECL)
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{
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DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0;
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if (maximum_field_alignment != 0)
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DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment);
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}
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if (DECL_BIT_FIELD (decl)
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&& TYPE_SIZE (type) != 0
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&& TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
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{
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register enum machine_mode xmode
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= mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1);
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if (xmode != BLKmode
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&& known_align % GET_MODE_ALIGNMENT (xmode) == 0)
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{
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DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode),
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DECL_ALIGN (decl));
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DECL_MODE (decl) = xmode;
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DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode));
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/* This no longer needs to be accessed as a bit field. */
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DECL_BIT_FIELD (decl) = 0;
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}
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}
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/* Evaluate nonconstant size only once, either now or as soon as safe. */
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if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST)
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DECL_SIZE (decl) = variable_size (DECL_SIZE (decl));
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}
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/* Lay out a RECORD_TYPE type (a C struct).
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This means laying out the fields, determining their positions,
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and computing the overall size and required alignment of the record.
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Note that if you set the TYPE_ALIGN before calling this
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then the struct is aligned to at least that boundary.
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If the type has basetypes, you must call layout_basetypes
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before calling this function.
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The return value is a list of static members of the record.
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They still need to be laid out. */
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static tree
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layout_record (rec)
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tree rec;
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{
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register tree field;
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#ifdef STRUCTURE_SIZE_BOUNDARY
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unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec));
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#else
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unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec));
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#endif
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/* These must be laid out *after* the record is. */
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tree pending_statics = NULL_TREE;
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/* Record size so far is CONST_SIZE + VAR_SIZE bits,
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where CONST_SIZE is an integer
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and VAR_SIZE is a tree expression.
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If VAR_SIZE is null, the size is just CONST_SIZE.
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Naturally we try to avoid using VAR_SIZE. */
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register int const_size = 0;
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register tree var_size = 0;
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/* Once we start using VAR_SIZE, this is the maximum alignment
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that we know VAR_SIZE has. */
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register int var_align = BITS_PER_UNIT;
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for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
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{
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register int known_align = var_size ? var_align : const_size;
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register int desired_align;
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|
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/* If FIELD is static, then treat it like a separate variable,
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not really like a structure field.
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If it is a FUNCTION_DECL, it's a method.
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In both cases, all we do is lay out the decl,
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and we do it *after* the record is laid out. */
|
||
|
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if (TREE_STATIC (field))
|
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{
|
||
pending_statics = tree_cons (NULL_TREE, field, pending_statics);
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continue;
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||
}
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/* Enumerators and enum types which are local to this class need not
|
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be laid out. Likewise for initialized constant fields. */
|
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if (TREE_CODE (field) != FIELD_DECL)
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||
continue;
|
||
|
||
/* Lay out the field so we know what alignment it needs.
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For a packed field, use the alignment as specified,
|
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disregarding what the type would want. */
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if (DECL_PACKED (field))
|
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desired_align = DECL_ALIGN (field);
|
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layout_decl (field, known_align);
|
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if (! DECL_PACKED (field))
|
||
desired_align = DECL_ALIGN (field);
|
||
/* Some targets (i.e. VMS) limit struct field alignment
|
||
to a lower boundary than alignment of variables. */
|
||
#ifdef BIGGEST_FIELD_ALIGNMENT
|
||
desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT);
|
||
#endif
|
||
|
||
/* Record must have at least as much alignment as any field.
|
||
Otherwise, the alignment of the field within the record
|
||
is meaningless. */
|
||
|
||
#ifndef PCC_BITFIELD_TYPE_MATTERS
|
||
record_align = MAX (record_align, desired_align);
|
||
#else
|
||
if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node
|
||
&& DECL_BIT_FIELD_TYPE (field)
|
||
&& ! integer_zerop (TYPE_SIZE (TREE_TYPE (field))))
|
||
{
|
||
/* For these machines, a zero-length field does not
|
||
affect the alignment of the structure as a whole.
|
||
It does, however, affect the alignment of the next field
|
||
within the structure. */
|
||
if (! integer_zerop (DECL_SIZE (field)))
|
||
record_align = MAX (record_align, desired_align);
|
||
else if (! DECL_PACKED (field))
|
||
desired_align = TYPE_ALIGN (TREE_TYPE (field));
|
||
/* A named bit field of declared type `int'
|
||
forces the entire structure to have `int' alignment. */
|
||
if (DECL_NAME (field) != 0)
|
||
{
|
||
int type_align = TYPE_ALIGN (TREE_TYPE (field));
|
||
if (maximum_field_alignment != 0)
|
||
type_align = MIN (type_align, maximum_field_alignment);
|
||
|
||
record_align = MAX (record_align, type_align);
|
||
}
|
||
}
|
||
else
|
||
record_align = MAX (record_align, desired_align);
|
||
#endif
|
||
|
||
/* Does this field automatically have alignment it needs
|
||
by virtue of the fields that precede it and the record's
|
||
own alignment? */
|
||
|
||
if (const_size % desired_align != 0
|
||
|| (var_align % desired_align != 0
|
||
&& var_size != 0))
|
||
{
|
||
/* No, we need to skip space before this field.
|
||
Bump the cumulative size to multiple of field alignment. */
|
||
|
||
if (var_size == 0
|
||
|| var_align % desired_align == 0)
|
||
const_size
|
||
= CEIL (const_size, desired_align) * desired_align;
|
||
else
|
||
{
|
||
if (const_size > 0)
|
||
var_size = size_binop (PLUS_EXPR, var_size,
|
||
size_int (const_size));
|
||
const_size = 0;
|
||
var_size = round_up (var_size, desired_align);
|
||
var_align = MIN (var_align, desired_align);
|
||
}
|
||
}
|
||
|
||
#ifdef PCC_BITFIELD_TYPE_MATTERS
|
||
if (PCC_BITFIELD_TYPE_MATTERS
|
||
&& TREE_CODE (field) == FIELD_DECL
|
||
&& TREE_TYPE (field) != error_mark_node
|
||
&& DECL_BIT_FIELD_TYPE (field)
|
||
&& !DECL_PACKED (field)
|
||
/* If #pragma pack is in effect, turn off this feature. */
|
||
&& maximum_field_alignment == 0
|
||
&& !integer_zerop (DECL_SIZE (field)))
|
||
{
|
||
int type_align = TYPE_ALIGN (TREE_TYPE (field));
|
||
register tree dsize = DECL_SIZE (field);
|
||
int field_size = TREE_INT_CST_LOW (dsize);
|
||
|
||
/* A bit field may not span the unit of alignment of its type.
|
||
Advance to next boundary if necessary. */
|
||
/* ??? There is some uncertainty here as to what
|
||
should be done if type_align is less than the width of the type.
|
||
That can happen because the width exceeds BIGGEST_ALIGNMENT
|
||
or because it exceeds maximum_field_alignment. */
|
||
if (const_size / type_align
|
||
!= (const_size + field_size - 1) / type_align)
|
||
const_size = CEIL (const_size, type_align) * type_align;
|
||
}
|
||
#endif
|
||
|
||
/* No existing machine description uses this parameter.
|
||
So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */
|
||
#ifdef BITFIELD_NBYTES_LIMITED
|
||
if (BITFIELD_NBYTES_LIMITED
|
||
&& TREE_CODE (field) == FIELD_DECL
|
||
&& TREE_TYPE (field) != error_mark_node
|
||
&& DECL_BIT_FIELD_TYPE (field)
|
||
&& !DECL_PACKED (field)
|
||
&& !integer_zerop (DECL_SIZE (field)))
|
||
{
|
||
int type_align = TYPE_ALIGN (TREE_TYPE (field));
|
||
register tree dsize = DECL_SIZE (field);
|
||
int field_size = TREE_INT_CST_LOW (dsize);
|
||
|
||
if (maximum_field_alignment != 0)
|
||
type_align = MIN (type_align, maximum_field_alignment);
|
||
|
||
/* A bit field may not span the unit of alignment of its type.
|
||
Advance to next boundary if necessary. */
|
||
if (const_size / type_align
|
||
!= (const_size + field_size - 1) / type_align)
|
||
const_size = CEIL (const_size, type_align) * type_align;
|
||
}
|
||
#endif
|
||
|
||
/* Size so far becomes the position of this field. */
|
||
|
||
if (var_size && const_size)
|
||
DECL_FIELD_BITPOS (field)
|
||
= size_binop (PLUS_EXPR, var_size, size_int (const_size));
|
||
else if (var_size)
|
||
DECL_FIELD_BITPOS (field) = var_size;
|
||
else
|
||
{
|
||
DECL_FIELD_BITPOS (field) = size_int (const_size);
|
||
|
||
/* If this field ended up more aligned than we thought it
|
||
would be (we approximate this by seeing if its position
|
||
changed), lay out the field again; perhaps we can use an
|
||
integral mode for it now. */
|
||
if (known_align != const_size)
|
||
layout_decl (field, const_size);
|
||
}
|
||
|
||
/* Now add size of this field to the size of the record. */
|
||
|
||
{
|
||
register tree dsize = DECL_SIZE (field);
|
||
|
||
/* This can happen when we have an invalid nested struct definition,
|
||
such as struct j { struct j { int i; } }. The error message is
|
||
printed in finish_struct. */
|
||
if (dsize == 0)
|
||
/* Do nothing. */;
|
||
else if (TREE_CODE (dsize) == INTEGER_CST
|
||
&& TREE_INT_CST_HIGH (dsize) == 0
|
||
&& TREE_INT_CST_LOW (dsize) + const_size > const_size)
|
||
/* Use const_size if there's no overflow. */
|
||
const_size += TREE_INT_CST_LOW (dsize);
|
||
else
|
||
{
|
||
if (var_size == 0)
|
||
var_size = dsize;
|
||
else
|
||
var_size = size_binop (PLUS_EXPR, var_size, dsize);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Work out the total size and alignment of the record
|
||
as one expression and store in the record type.
|
||
Round it up to a multiple of the record's alignment. */
|
||
|
||
if (var_size == 0)
|
||
{
|
||
TYPE_SIZE (rec) = size_int (const_size);
|
||
}
|
||
else
|
||
{
|
||
if (const_size)
|
||
var_size
|
||
= size_binop (PLUS_EXPR, var_size, size_int (const_size));
|
||
TYPE_SIZE (rec) = var_size;
|
||
}
|
||
|
||
/* Determine the desired alignment. */
|
||
#ifdef ROUND_TYPE_ALIGN
|
||
TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align);
|
||
#else
|
||
TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align);
|
||
#endif
|
||
|
||
#ifdef ROUND_TYPE_SIZE
|
||
TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
|
||
#else
|
||
/* Round the size up to be a multiple of the required alignment */
|
||
TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
|
||
#endif
|
||
|
||
return pending_statics;
|
||
}
|
||
|
||
/* Lay out a UNION_TYPE or QUAL_UNION_TYPE type.
|
||
Lay out all the fields, set their positions to zero,
|
||
and compute the size and alignment of the union (maximum of any field).
|
||
Note that if you set the TYPE_ALIGN before calling this
|
||
then the union align is aligned to at least that boundary. */
|
||
|
||
static void
|
||
layout_union (rec)
|
||
tree rec;
|
||
{
|
||
register tree field;
|
||
#ifdef STRUCTURE_SIZE_BOUNDARY
|
||
unsigned union_align = STRUCTURE_SIZE_BOUNDARY;
|
||
#else
|
||
unsigned union_align = BITS_PER_UNIT;
|
||
#endif
|
||
|
||
/* The size of the union, based on the fields scanned so far,
|
||
is max (CONST_SIZE, VAR_SIZE).
|
||
VAR_SIZE may be null; then CONST_SIZE by itself is the size. */
|
||
register int const_size = 0;
|
||
register tree var_size = 0;
|
||
|
||
/* If this is a QUAL_UNION_TYPE, we want to process the fields in
|
||
the reverse order in building the COND_EXPR that denotes its
|
||
size. We reverse them again later. */
|
||
if (TREE_CODE (rec) == QUAL_UNION_TYPE)
|
||
TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
|
||
|
||
for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field))
|
||
{
|
||
/* Enums which are local to this class need not be laid out. */
|
||
if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL)
|
||
continue;
|
||
|
||
layout_decl (field, 0);
|
||
DECL_FIELD_BITPOS (field) = size_int (0);
|
||
|
||
/* Union must be at least as aligned as any field requires. */
|
||
|
||
union_align = MAX (union_align, DECL_ALIGN (field));
|
||
|
||
#ifdef PCC_BITFIELD_TYPE_MATTERS
|
||
/* On the m88000, a bit field of declare type `int'
|
||
forces the entire union to have `int' alignment. */
|
||
if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field))
|
||
union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field)));
|
||
#endif
|
||
|
||
if (TREE_CODE (rec) == UNION_TYPE)
|
||
{
|
||
/* Set union_size to max (decl_size, union_size).
|
||
There are more and less general ways to do this.
|
||
Use only CONST_SIZE unless forced to use VAR_SIZE. */
|
||
|
||
if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST)
|
||
const_size
|
||
= MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field)));
|
||
else if (var_size == 0)
|
||
var_size = DECL_SIZE (field);
|
||
else
|
||
var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field));
|
||
}
|
||
else if (TREE_CODE (rec) == QUAL_UNION_TYPE)
|
||
var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field),
|
||
DECL_SIZE (field),
|
||
var_size ? var_size : integer_zero_node));
|
||
}
|
||
|
||
if (TREE_CODE (rec) == QUAL_UNION_TYPE)
|
||
TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec));
|
||
|
||
/* Determine the ultimate size of the union (in bytes). */
|
||
if (NULL == var_size)
|
||
TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT)
|
||
* BITS_PER_UNIT);
|
||
else if (const_size == 0)
|
||
TYPE_SIZE (rec) = var_size;
|
||
else
|
||
TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size,
|
||
round_up (size_int (const_size),
|
||
BITS_PER_UNIT));
|
||
|
||
/* Determine the desired alignment. */
|
||
#ifdef ROUND_TYPE_ALIGN
|
||
TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align);
|
||
#else
|
||
TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align);
|
||
#endif
|
||
|
||
#ifdef ROUND_TYPE_SIZE
|
||
TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec));
|
||
#else
|
||
/* Round the size up to be a multiple of the required alignment */
|
||
TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec));
|
||
#endif
|
||
}
|
||
|
||
/* Calculate the mode, size, and alignment for TYPE.
|
||
For an array type, calculate the element separation as well.
|
||
Record TYPE on the chain of permanent or temporary types
|
||
so that dbxout will find out about it.
|
||
|
||
TYPE_SIZE of a type is nonzero if the type has been laid out already.
|
||
layout_type does nothing on such a type.
|
||
|
||
If the type is incomplete, its TYPE_SIZE remains zero. */
|
||
|
||
void
|
||
layout_type (type)
|
||
tree type;
|
||
{
|
||
int old;
|
||
tree pending_statics;
|
||
|
||
if (type == 0)
|
||
abort ();
|
||
|
||
/* Do nothing if type has been laid out before. */
|
||
if (TYPE_SIZE (type))
|
||
return;
|
||
|
||
/* Make sure all nodes we allocate are not momentary;
|
||
they must last past the current statement. */
|
||
old = suspend_momentary ();
|
||
|
||
/* Put all our nodes into the same obstack as the type. Also,
|
||
make expressions saveable (this is a no-op for permanent types). */
|
||
|
||
push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type));
|
||
saveable_allocation ();
|
||
|
||
switch (TREE_CODE (type))
|
||
{
|
||
case LANG_TYPE:
|
||
/* This kind of type is the responsibility
|
||
of the languge-specific code. */
|
||
abort ();
|
||
|
||
case INTEGER_TYPE:
|
||
case ENUMERAL_TYPE:
|
||
if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
|
||
&& tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
|
||
TREE_UNSIGNED (type) = 1;
|
||
|
||
TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type),
|
||
MODE_INT);
|
||
TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
|
||
break;
|
||
|
||
case REAL_TYPE:
|
||
TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0);
|
||
TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
|
||
break;
|
||
|
||
case COMPLEX_TYPE:
|
||
TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type));
|
||
TYPE_MODE (type)
|
||
= mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)),
|
||
(TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE
|
||
? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT),
|
||
0);
|
||
TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
|
||
break;
|
||
|
||
case VOID_TYPE:
|
||
TYPE_SIZE (type) = size_zero_node;
|
||
TYPE_ALIGN (type) = 1;
|
||
TYPE_MODE (type) = VOIDmode;
|
||
break;
|
||
|
||
case OFFSET_TYPE:
|
||
TYPE_SIZE (type) = size_int (POINTER_SIZE);
|
||
TYPE_MODE (type) = mode_for_size (POINTER_SIZE,
|
||
GET_MODE_CLASS (Pmode), 0);
|
||
break;
|
||
|
||
case FUNCTION_TYPE:
|
||
case METHOD_TYPE:
|
||
TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0);
|
||
TYPE_SIZE (type) = size_int (2 * POINTER_SIZE);
|
||
break;
|
||
|
||
case POINTER_TYPE:
|
||
case REFERENCE_TYPE:
|
||
TYPE_MODE (type) = mode_for_size (POINTER_SIZE,
|
||
GET_MODE_CLASS (Pmode), 0);
|
||
TYPE_SIZE (type) = size_int (POINTER_SIZE);
|
||
TREE_UNSIGNED (type) = 1;
|
||
TYPE_PRECISION (type) = POINTER_SIZE;
|
||
break;
|
||
|
||
case ARRAY_TYPE:
|
||
{
|
||
register tree index = TYPE_DOMAIN (type);
|
||
register tree element = TREE_TYPE (type);
|
||
|
||
build_pointer_type (element);
|
||
|
||
/* We need to know both bounds in order to compute the size. */
|
||
if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index)
|
||
&& TYPE_SIZE (element))
|
||
{
|
||
tree length
|
||
= size_binop (PLUS_EXPR, size_one_node,
|
||
size_binop (MINUS_EXPR, TYPE_MAX_VALUE (index),
|
||
TYPE_MIN_VALUE (index)));
|
||
|
||
TYPE_SIZE (type) = size_binop (MULT_EXPR, length,
|
||
TYPE_SIZE (element));
|
||
}
|
||
|
||
/* Now round the alignment and size,
|
||
using machine-dependent criteria if any. */
|
||
|
||
#ifdef ROUND_TYPE_ALIGN
|
||
TYPE_ALIGN (type)
|
||
= ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT);
|
||
#else
|
||
TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT);
|
||
#endif
|
||
|
||
#ifdef ROUND_TYPE_SIZE
|
||
if (TYPE_SIZE (type) != 0)
|
||
TYPE_SIZE (type)
|
||
= ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type));
|
||
#endif
|
||
|
||
TYPE_MODE (type) = BLKmode;
|
||
if (TYPE_SIZE (type) != 0
|
||
&& TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
|
||
/* BLKmode elements force BLKmode aggregate;
|
||
else extract/store fields may lose. */
|
||
&& (TYPE_MODE (TREE_TYPE (type)) != BLKmode
|
||
|| TYPE_NO_FORCE_BLK (TREE_TYPE (type))))
|
||
{
|
||
TYPE_MODE (type)
|
||
= mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
|
||
MODE_INT, 1);
|
||
|
||
if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT
|
||
&& TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type))
|
||
&& TYPE_MODE (type) != BLKmode)
|
||
{
|
||
TYPE_NO_FORCE_BLK (type) = 1;
|
||
TYPE_MODE (type) = BLKmode;
|
||
}
|
||
}
|
||
break;
|
||
}
|
||
|
||
case RECORD_TYPE:
|
||
pending_statics = layout_record (type);
|
||
TYPE_MODE (type) = BLKmode;
|
||
if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
|
||
{
|
||
tree field;
|
||
/* A record which has any BLKmode members must itself be BLKmode;
|
||
it can't go in a register.
|
||
Unless the member is BLKmode only because it isn't aligned. */
|
||
for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
|
||
{
|
||
int bitpos;
|
||
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
|
||
&& ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
|
||
goto record_lose;
|
||
|
||
if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST)
|
||
goto record_lose;
|
||
|
||
bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field));
|
||
|
||
/* Must be BLKmode if any field crosses a word boundary,
|
||
since extract_bit_field can't handle that in registers. */
|
||
if (bitpos / BITS_PER_WORD
|
||
!= ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1)
|
||
/ BITS_PER_WORD)
|
||
/* But there is no problem if the field is entire words. */
|
||
&& TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0)
|
||
goto record_lose;
|
||
}
|
||
|
||
TYPE_MODE (type)
|
||
= mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
|
||
MODE_INT, 1);
|
||
|
||
/* If structure's known alignment is less than
|
||
what the scalar mode would need, and it matters,
|
||
then stick with BLKmode. */
|
||
if (STRICT_ALIGNMENT
|
||
&& ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
|
||
|| (TYPE_ALIGN (type)
|
||
>= TREE_INT_CST_LOW (TYPE_SIZE (type)))))
|
||
{
|
||
if (TYPE_MODE (type) != BLKmode)
|
||
/* If this is the only reason this type is BLKmode,
|
||
then don't force containing types to be BLKmode. */
|
||
TYPE_NO_FORCE_BLK (type) = 1;
|
||
TYPE_MODE (type) = BLKmode;
|
||
}
|
||
|
||
record_lose: ;
|
||
}
|
||
|
||
/* Lay out any static members. This is done now
|
||
because their type may use the record's type. */
|
||
while (pending_statics)
|
||
{
|
||
layout_decl (TREE_VALUE (pending_statics), 0);
|
||
pending_statics = TREE_CHAIN (pending_statics);
|
||
}
|
||
break;
|
||
|
||
case UNION_TYPE:
|
||
case QUAL_UNION_TYPE:
|
||
layout_union (type);
|
||
TYPE_MODE (type) = BLKmode;
|
||
if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
|
||
/* If structure's known alignment is less than
|
||
what the scalar mode would need, and it matters,
|
||
then stick with BLKmode. */
|
||
&& (! STRICT_ALIGNMENT
|
||
|| TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT
|
||
|| TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type))))
|
||
{
|
||
tree field;
|
||
/* A union which has any BLKmode members must itself be BLKmode;
|
||
it can't go in a register.
|
||
Unless the member is BLKmode only because it isn't aligned. */
|
||
for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
|
||
{
|
||
if (TREE_CODE (field) != FIELD_DECL)
|
||
continue;
|
||
|
||
if (TYPE_MODE (TREE_TYPE (field)) == BLKmode
|
||
&& ! TYPE_NO_FORCE_BLK (TREE_TYPE (field)))
|
||
goto union_lose;
|
||
}
|
||
|
||
TYPE_MODE (type)
|
||
= mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)),
|
||
MODE_INT, 1);
|
||
|
||
union_lose: ;
|
||
}
|
||
break;
|
||
|
||
/* Pascal and Chill types */
|
||
case BOOLEAN_TYPE: /* store one byte/boolean for now. */
|
||
TYPE_MODE (type) = QImode;
|
||
TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
|
||
TYPE_PRECISION (type) = 1;
|
||
TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
|
||
if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST
|
||
&& tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0)
|
||
TREE_UNSIGNED (type) = 1;
|
||
break;
|
||
|
||
case CHAR_TYPE:
|
||
TYPE_MODE (type) = QImode;
|
||
TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type)));
|
||
TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type));
|
||
TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
|
||
break;
|
||
|
||
case SET_TYPE:
|
||
if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST
|
||
|| TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST)
|
||
abort();
|
||
else
|
||
{
|
||
#ifndef SET_WORD_SIZE
|
||
#define SET_WORD_SIZE BITS_PER_WORD
|
||
#endif
|
||
int alignment = set_alignment ? set_alignment : SET_WORD_SIZE;
|
||
int size_in_bits =
|
||
TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type)))
|
||
- TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1;
|
||
int rounded_size
|
||
= ((size_in_bits + alignment - 1) / alignment) * alignment;
|
||
if (rounded_size > alignment)
|
||
TYPE_MODE (type) = BLKmode;
|
||
else
|
||
TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1);
|
||
TYPE_SIZE (type) = size_int (rounded_size);
|
||
TYPE_ALIGN (type) = alignment;
|
||
TYPE_PRECISION (type) = size_in_bits;
|
||
}
|
||
break;
|
||
|
||
case FILE_TYPE:
|
||
/* The size may vary in different languages, so the language front end
|
||
should fill in the size. */
|
||
TYPE_ALIGN (type) = BIGGEST_ALIGNMENT;
|
||
TYPE_MODE (type) = BLKmode;
|
||
break;
|
||
|
||
default:
|
||
abort ();
|
||
} /* end switch */
|
||
|
||
/* Normally, use the alignment corresponding to the mode chosen.
|
||
However, where strict alignment is not required, avoid
|
||
over-aligning structures, since most compilers do not do this
|
||
alignment. */
|
||
|
||
if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode
|
||
&& (STRICT_ALIGNMENT
|
||
|| (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE
|
||
&& TREE_CODE (type) != QUAL_UNION_TYPE
|
||
&& TREE_CODE (type) != ARRAY_TYPE)))
|
||
TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type));
|
||
|
||
/* Evaluate nonconstant size only once, either now or as soon as safe. */
|
||
if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
|
||
TYPE_SIZE (type) = variable_size (TYPE_SIZE (type));
|
||
|
||
/* Also layout any other variants of the type. */
|
||
if (TYPE_NEXT_VARIANT (type)
|
||
|| type != TYPE_MAIN_VARIANT (type))
|
||
{
|
||
tree variant;
|
||
/* Record layout info of this variant. */
|
||
tree size = TYPE_SIZE (type);
|
||
int align = TYPE_ALIGN (type);
|
||
enum machine_mode mode = TYPE_MODE (type);
|
||
|
||
/* Copy it into all variants. */
|
||
for (variant = TYPE_MAIN_VARIANT (type);
|
||
variant;
|
||
variant = TYPE_NEXT_VARIANT (variant))
|
||
{
|
||
TYPE_SIZE (variant) = size;
|
||
TYPE_ALIGN (variant) = align;
|
||
TYPE_MODE (variant) = mode;
|
||
}
|
||
}
|
||
|
||
pop_obstacks ();
|
||
resume_momentary (old);
|
||
}
|
||
|
||
/* Create and return a type for signed integers of PRECISION bits. */
|
||
|
||
tree
|
||
make_signed_type (precision)
|
||
int precision;
|
||
{
|
||
register tree type = make_node (INTEGER_TYPE);
|
||
|
||
TYPE_PRECISION (type) = precision;
|
||
|
||
/* Create the extreme values based on the number of bits. */
|
||
|
||
TYPE_MIN_VALUE (type)
|
||
= build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
|
||
? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
|
||
(((HOST_WIDE_INT) (-1)
|
||
<< (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
|
||
? precision - HOST_BITS_PER_WIDE_INT - 1
|
||
: 0))));
|
||
TYPE_MAX_VALUE (type)
|
||
= build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
|
||
? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
|
||
(precision - HOST_BITS_PER_WIDE_INT - 1 > 0
|
||
? (((HOST_WIDE_INT) 1
|
||
<< (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
|
||
: 0));
|
||
|
||
/* Give this type's extreme values this type as their type. */
|
||
|
||
TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
|
||
TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
|
||
|
||
/* The first type made with this or `make_unsigned_type'
|
||
is the type for size values. */
|
||
|
||
if (sizetype == 0)
|
||
{
|
||
sizetype = type;
|
||
}
|
||
|
||
/* Lay out the type: set its alignment, size, etc. */
|
||
|
||
layout_type (type);
|
||
|
||
return type;
|
||
}
|
||
|
||
/* Create and return a type for unsigned integers of PRECISION bits. */
|
||
|
||
tree
|
||
make_unsigned_type (precision)
|
||
int precision;
|
||
{
|
||
register tree type = make_node (INTEGER_TYPE);
|
||
|
||
TYPE_PRECISION (type) = precision;
|
||
|
||
/* The first type made with this or `make_signed_type'
|
||
is the type for size values. */
|
||
|
||
if (sizetype == 0)
|
||
{
|
||
sizetype = type;
|
||
}
|
||
|
||
fixup_unsigned_type (type);
|
||
return type;
|
||
}
|
||
|
||
/* Set the extreme values of TYPE based on its precision in bits,
|
||
then lay it out. Used when make_signed_type won't do
|
||
because the tree code is not INTEGER_TYPE.
|
||
E.g. for Pascal, when the -fsigned-char option is given. */
|
||
|
||
void
|
||
fixup_signed_type (type)
|
||
tree type;
|
||
{
|
||
register int precision = TYPE_PRECISION (type);
|
||
|
||
TYPE_MIN_VALUE (type)
|
||
= build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
|
||
? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)),
|
||
(((HOST_WIDE_INT) (-1)
|
||
<< (precision - HOST_BITS_PER_WIDE_INT - 1 > 0
|
||
? precision - HOST_BITS_PER_WIDE_INT - 1
|
||
: 0))));
|
||
TYPE_MAX_VALUE (type)
|
||
= build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0
|
||
? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1),
|
||
(precision - HOST_BITS_PER_WIDE_INT - 1 > 0
|
||
? (((HOST_WIDE_INT) 1
|
||
<< (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1
|
||
: 0));
|
||
|
||
TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
|
||
TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
|
||
|
||
/* Lay out the type: set its alignment, size, etc. */
|
||
|
||
layout_type (type);
|
||
}
|
||
|
||
/* Set the extreme values of TYPE based on its precision in bits,
|
||
then lay it out. This is used both in `make_unsigned_type'
|
||
and for enumeral types. */
|
||
|
||
void
|
||
fixup_unsigned_type (type)
|
||
tree type;
|
||
{
|
||
register int precision = TYPE_PRECISION (type);
|
||
|
||
TYPE_MIN_VALUE (type) = build_int_2 (0, 0);
|
||
TYPE_MAX_VALUE (type)
|
||
= build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0
|
||
? -1 : ((HOST_WIDE_INT) 1 << precision) - 1,
|
||
precision - HOST_BITS_PER_WIDE_INT > 0
|
||
? ((unsigned HOST_WIDE_INT) ~0
|
||
>> (HOST_BITS_PER_WIDE_INT
|
||
- (precision - HOST_BITS_PER_WIDE_INT)))
|
||
: 0);
|
||
TREE_TYPE (TYPE_MIN_VALUE (type)) = type;
|
||
TREE_TYPE (TYPE_MAX_VALUE (type)) = type;
|
||
|
||
/* Lay out the type: set its alignment, size, etc. */
|
||
|
||
layout_type (type);
|
||
}
|
||
|
||
/* Find the best machine mode to use when referencing a bit field of length
|
||
BITSIZE bits starting at BITPOS.
|
||
|
||
The underlying object is known to be aligned to a boundary of ALIGN bits.
|
||
If LARGEST_MODE is not VOIDmode, it means that we should not use a mode
|
||
larger than LARGEST_MODE (usually SImode).
|
||
|
||
If no mode meets all these conditions, we return VOIDmode. Otherwise, if
|
||
VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest
|
||
mode meeting these conditions.
|
||
|
||
Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return
|
||
the largest mode (but a mode no wider than UNITS_PER_WORD) that meets
|
||
all the conditions. */
|
||
|
||
enum machine_mode
|
||
get_best_mode (bitsize, bitpos, align, largest_mode, volatilep)
|
||
int bitsize, bitpos;
|
||
int align;
|
||
enum machine_mode largest_mode;
|
||
int volatilep;
|
||
{
|
||
enum machine_mode mode;
|
||
int unit;
|
||
|
||
/* Find the narrowest integer mode that contains the bit field. */
|
||
for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode;
|
||
mode = GET_MODE_WIDER_MODE (mode))
|
||
{
|
||
unit = GET_MODE_BITSIZE (mode);
|
||
if (bitpos / unit == (bitpos + bitsize - 1) / unit)
|
||
break;
|
||
}
|
||
|
||
if (mode == MAX_MACHINE_MODE
|
||
/* It is tempting to omit the following line
|
||
if STRICT_ALIGNMENT is true.
|
||
But that is incorrect, since if the bitfield uses part of 3 bytes
|
||
and we use a 4-byte mode, we could get a spurious segv
|
||
if the extra 4th byte is past the end of memory.
|
||
(Though at least one Unix compiler ignores this problem:
|
||
that on the Sequent 386 machine. */
|
||
|| MIN (unit, BIGGEST_ALIGNMENT) > align
|
||
|| (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode)))
|
||
return VOIDmode;
|
||
|
||
if (SLOW_BYTE_ACCESS && ! volatilep)
|
||
{
|
||
enum machine_mode wide_mode = VOIDmode, tmode;
|
||
|
||
for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode;
|
||
tmode = GET_MODE_WIDER_MODE (tmode))
|
||
{
|
||
unit = GET_MODE_BITSIZE (tmode);
|
||
if (bitpos / unit == (bitpos + bitsize - 1) / unit
|
||
&& unit <= BITS_PER_WORD
|
||
&& unit <= MIN (align, BIGGEST_ALIGNMENT)
|
||
&& (largest_mode == VOIDmode
|
||
|| unit <= GET_MODE_BITSIZE (largest_mode)))
|
||
wide_mode = tmode;
|
||
}
|
||
|
||
if (wide_mode != VOIDmode)
|
||
return wide_mode;
|
||
}
|
||
|
||
return mode;
|
||
}
|
||
|
||
/* Save all variables describing the current status into the structure *P.
|
||
This is used before starting a nested function. */
|
||
|
||
void
|
||
save_storage_status (p)
|
||
struct function *p;
|
||
{
|
||
#if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */
|
||
p->pending_sizes = pending_sizes;
|
||
p->immediate_size_expand = immediate_size_expand;
|
||
#endif /* 0 */
|
||
}
|
||
|
||
/* Restore all variables describing the current status from the structure *P.
|
||
This is used after a nested function. */
|
||
|
||
void
|
||
restore_storage_status (p)
|
||
struct function *p;
|
||
{
|
||
#if 0
|
||
pending_sizes = p->pending_sizes;
|
||
immediate_size_expand = p->immediate_size_expand;
|
||
#endif /* 0 */
|
||
}
|