501 lines
11 KiB
C
501 lines
11 KiB
C
/* Handle #pragma, system V.4 style. Supports #pragma weak and #pragma pack.
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Copyright (C) 1992, 1997, 1998, 1999 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
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GNU General Public License for more details.
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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, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "config.h"
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#include "system.h"
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#include "rtl.h"
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#include "tree.h"
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#include "except.h"
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#include "function.h"
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#include "defaults.h"
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#include "c-pragma.h"
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#include "flags.h"
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#include "toplev.h"
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#ifdef HANDLE_GENERIC_PRAGMAS
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#ifdef HANDLE_PRAGMA_PACK
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/* When structure field packing is in effect, this variable is the
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number of bits to use as the maximum alignment. When packing is not
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in effect, this is zero. */
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extern int maximum_field_alignment;
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#endif
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#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
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typedef struct align_stack
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{
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int alignment;
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unsigned int num_pushes;
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tree id;
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struct align_stack * prev;
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} align_stack;
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static struct align_stack * alignment_stack = NULL;
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static int push_alignment PROTO((int, tree));
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static int pop_alignment PROTO((tree));
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/* Push an alignment value onto the stack. */
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static int
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push_alignment (alignment, id)
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int alignment;
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tree id;
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{
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switch (alignment)
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{
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case 0:
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case 1:
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case 2:
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case 4:
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case 8:
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case 16:
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break;
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default:
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warning ("\
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Alignment must be a small power of two, not %d, in #pragma pack",
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alignment);
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return 0;
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}
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if (alignment_stack == NULL
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|| alignment_stack->alignment != alignment
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|| id != NULL_TREE)
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{
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align_stack * entry;
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entry = (align_stack *) xmalloc (sizeof (* entry));
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if (entry == NULL)
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{
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warning ("Out of memory pushing #pragma pack");
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return 0;
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}
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entry->alignment = alignment;
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entry->num_pushes = 1;
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entry->id = id;
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entry->prev = alignment_stack;
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alignment_stack = entry;
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maximum_field_alignment = alignment * 8;
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}
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else
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alignment_stack->num_pushes ++;
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return 1;
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}
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/* Undo a push of an alignment onto the stack. */
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static int
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pop_alignment (id)
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tree id;
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{
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align_stack * entry;
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if (alignment_stack == NULL)
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{
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warning ("\
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#pragma pack (pop) encountered without matching #pragma pack (push, <n>)"
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);
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return 0;
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}
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/* If we got an identifier, strip away everything above the target
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entry so that the next step will restore the state just below it. */
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if (id)
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{
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for (entry = alignment_stack; entry; entry = entry->prev)
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if (entry->id == id)
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{
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entry->num_pushes = 1;
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alignment_stack = entry;
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break;
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}
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if (entry == NULL)
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warning ("\
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#pragma pack(pop, %s) encountered without matching #pragma pack(push, %s, <n>)"
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, IDENTIFIER_POINTER (id), IDENTIFIER_POINTER (id));
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}
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if (-- alignment_stack->num_pushes == 0)
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{
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entry = alignment_stack->prev;
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if (entry == NULL)
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maximum_field_alignment = 0;
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else
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maximum_field_alignment = entry->alignment * 8;
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free (alignment_stack);
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alignment_stack = entry;
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}
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return 1;
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}
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/* Generate 'packed' and 'aligned' attributes for decls whilst a
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#pragma pack(push... is in effect. */
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void
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insert_pack_attributes (node, attributes, prefix)
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tree node;
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tree * attributes;
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tree * prefix;
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{
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tree a;
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int field_alignment;
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/* If we are not packing, then there is nothing to do. */
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if (maximum_field_alignment == 0
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|| alignment_stack == NULL)
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return;
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/* We are only interested in fields. */
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if (TREE_CODE_CLASS (TREE_CODE (node)) != 'd'
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|| TREE_CODE (node) != FIELD_DECL)
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return;
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field_alignment = TYPE_ALIGN (TREE_TYPE (node));
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if (field_alignment <= 0 || field_alignment > maximum_field_alignment)
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field_alignment = maximum_field_alignment;
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/* Add a 'packed' attribute. */
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* attributes = tree_cons (get_identifier ("packed"), NULL, * attributes);
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/* If the alignment is > 8 then add an alignment attribute as well. */
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if (field_alignment > 8)
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{
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/* If the aligned attribute is already present then do not override it. */
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for (a = * attributes; a; a = TREE_CHAIN (a))
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{
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tree name = TREE_PURPOSE (a);
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if (strcmp (IDENTIFIER_POINTER (name), "aligned") == 0)
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break;
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}
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if (a == NULL)
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for (a = * prefix; a; a = TREE_CHAIN (a))
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{
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tree name = TREE_PURPOSE (a);
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if (strcmp (IDENTIFIER_POINTER (name), "aligned") == 0)
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break;
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}
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if (a == NULL)
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{
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* attributes = tree_cons
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(get_identifier ("aligned"),
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tree_cons (NULL,
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build_int_2 (field_alignment / 8, 0),
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NULL),
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* attributes);
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}
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}
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return;
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}
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#endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
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/* Handle one token of a pragma directive. TOKEN is the current token, and
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STRING is its printable form. Some front ends do not support generating
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tokens, and will only pass in a STRING. Also some front ends will reuse
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the buffer containing STRING, so it must be copied to a local buffer if
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it needs to be preserved.
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If STRING is non-NULL, then the return value will be ignored, and there
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will be futher calls to handle_pragma_token() in order to handle the rest of
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the line containing the #pragma directive. If STRING is NULL, the entire
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line has now been presented to handle_pragma_token() and the return value
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should be zero if the pragma flawed in some way, or if the pragma was not
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recognised, and non-zero if it was successfully handled. */
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int
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handle_pragma_token (string, token)
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const char * string;
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tree token;
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{
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static enum pragma_state state = ps_start;
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static enum pragma_state type;
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static char * name;
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static char * value;
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static int align;
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static tree id;
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/* If we have reached the end of the #pragma directive then
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determine what value we should return. */
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if (string == NULL)
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{
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int ret_val = 0;
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switch (type)
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{
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default:
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abort ();
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break;
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case ps_done:
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/* The pragma was not recognised. */
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break;
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#ifdef HANDLE_PRAGMA_PACK
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case ps_pack:
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if (state == ps_right)
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{
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maximum_field_alignment = align * 8;
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ret_val = 1;
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}
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else
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warning ("malformed `#pragma pack'");
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break;
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#endif /* HANDLE_PRAGMA_PACK */
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#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
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case ps_push:
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if (state == ps_right)
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ret_val = push_alignment (align, id);
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else
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warning ("malformed '#pragma pack(push[,id],<n>)'");
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break;
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case ps_pop:
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if (state == ps_right)
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ret_val = pop_alignment (id);
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else
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warning ("malformed '#pragma pack(pop[,id])'");
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break;
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#endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
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#ifdef HANDLE_PRAGMA_WEAK
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case ps_weak:
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if (HANDLE_PRAGMA_WEAK)
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{
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if (state == ps_name)
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ret_val = add_weak (name, NULL);
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else if (state == ps_value)
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ret_val = add_weak (name, value);
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else
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warning ("malformed `#pragma weak'");
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}
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else
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ret_val = 1; /* Ignore the pragma. */
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break;
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#endif /* HANDLE_PRAGMA_WEAK */
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}
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type = state = ps_start;
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id = NULL_TREE;
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return ret_val;
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}
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/* If we have been given a token, but it is not an identifier,
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or a small constant, then something has gone wrong. */
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if (token)
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{
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switch (TREE_CODE (token))
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{
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case IDENTIFIER_NODE:
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break;
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case INTEGER_CST:
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if (TREE_INT_CST_HIGH (token) != 0)
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return 0;
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break;
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default:
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return 0;
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}
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}
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switch (state)
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{
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case ps_start:
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type = state = ps_done;
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#ifdef HANDLE_PRAGMA_PACK
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if (strcmp (string, "pack") == 0)
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type = state = ps_pack;
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#endif
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#ifdef HANDLE_PRAGMA_WEAK
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if (strcmp (string, "weak") == 0)
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type = state = ps_weak;
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#endif
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break;
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#ifdef HANDLE_PRAGMA_WEAK
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case ps_weak:
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name = permalloc (strlen (string) + 1);
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if (name == NULL)
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{
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warning ("Out of memory parsing #pragma weak");
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state = ps_bad;
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}
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else
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{
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strcpy (name, string);
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state = ps_name;
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}
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break;
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case ps_name:
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state = (strcmp (string, "=") ? ps_bad : ps_equals);
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break;
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case ps_equals:
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value = permalloc (strlen (string) + 1);
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if (value == NULL)
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{
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warning ("Out of memory parsing #pragma weak");
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state = ps_bad;
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}
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else
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{
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strcpy (value, string);
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state = ps_value;
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}
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break;
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case ps_value:
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state = ps_bad;
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break;
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#endif /* HANDLE_PRAGMA_WEAK */
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#ifdef HANDLE_PRAGMA_PACK
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case ps_pack:
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state = (strcmp (string, "(") ? ps_bad : ps_left);
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break;
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case ps_left:
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if (token == NULL_TREE)
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{
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/* #pragma pack () resets packing rules to their
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defaults. */
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if (strcmp (string, ")") == 0)
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{
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align = 0;
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state = ps_right;
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}
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else
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state = ps_bad;
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}
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else if (TREE_CODE (token) == INTEGER_CST)
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goto handle_align;
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#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
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else if (TREE_CODE (token) == IDENTIFIER_NODE)
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{
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if (strcmp (string, "push") == 0)
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type = state = ps_push;
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else if (strcmp (string, "pop") == 0)
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type = state = ps_pop;
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else
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state = ps_bad;
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}
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#endif
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else
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state = ps_bad;
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break;
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handle_align:
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align = TREE_INT_CST_LOW (token);
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switch (align)
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{
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case 1:
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case 2:
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case 4:
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case 8:
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case 16:
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state = ps_align;
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break;
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default:
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state = ps_bad;
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break;
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}
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break;
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case ps_align:
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state = (strcmp (string, ")") ? ps_bad : ps_right);
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break;
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case ps_right:
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state = ps_bad;
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break;
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#endif /* HANDLE_PRAGMA_PACK */
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#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
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case ps_push:
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state = (strcmp (string, ",") ? ps_bad : ps_pushcomma);
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break;
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case ps_pushid:
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state = (strcmp (string, ",") ? ps_bad : ps_pushcomma2);
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break;
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case ps_pushcomma:
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if (token && TREE_CODE (token) == IDENTIFIER_NODE)
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{
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id = token;
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state = ps_pushid;
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break;
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}
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/* else fall through */
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case ps_pushcomma2:
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if (token && TREE_CODE (token) == INTEGER_CST)
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goto handle_align;
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else
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state = ps_bad;
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break;
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case ps_pop:
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if (strcmp (string, ",") == 0)
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state = ps_popcomma;
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else
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state = (strcmp (string, ")") ? ps_bad : ps_right);
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break;
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case ps_popcomma:
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if (token && TREE_CODE (token) == IDENTIFIER_NODE)
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{
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id = token;
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state = ps_align;
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}
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else
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state = ps_bad;
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break;
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#endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
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case ps_bad:
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case ps_done:
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break;
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default:
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abort ();
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}
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return 1;
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}
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#endif /* HANDLE_GENERIC_PRAGMAS */
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