469 lines
14 KiB
C
469 lines
14 KiB
C
/* Functions dealing with attribute handling, used by most front ends.
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Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
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2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
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Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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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 GCC; see the file COPYING3. If not see
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<http://www.gnu.org/licenses/>. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "flags.h"
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#include "toplev.h"
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#include "output.h"
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#include "rtl.h"
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#include "ggc.h"
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#include "tm_p.h"
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#include "cpplib.h"
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#include "target.h"
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#include "langhooks.h"
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#include "hashtab.h"
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#include "plugin.h"
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static void init_attributes (void);
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/* Table of the tables of attributes (common, language, format, machine)
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searched. */
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static const struct attribute_spec *attribute_tables[4];
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/* Hashtable mapping names (represented as substrings) to attribute specs. */
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static htab_t attribute_hash;
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/* Substring representation. */
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struct substring
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{
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const char *str;
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int length;
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};
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static bool attributes_initialized = false;
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/* Default empty table of attributes. */
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static const struct attribute_spec empty_attribute_table[] =
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{
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{ NULL, 0, 0, false, false, false, NULL }
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};
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/* Return base name of the attribute. Ie '__attr__' is turned into 'attr'.
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To avoid need for copying, we simply return length of the string. */
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static void
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extract_attribute_substring (struct substring *str)
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{
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if (str->length > 4 && str->str[0] == '_' && str->str[1] == '_'
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&& str->str[str->length - 1] == '_' && str->str[str->length - 2] == '_')
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{
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str->length -= 4;
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str->str += 2;
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}
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}
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/* Simple hash function to avoid need to scan whole string. */
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static inline hashval_t
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substring_hash (const char *str, int l)
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{
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return str[0] + str[l - 1] * 256 + l * 65536;
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}
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/* Used for attribute_hash. */
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static hashval_t
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hash_attr (const void *p)
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{
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const struct attribute_spec *const spec = (const struct attribute_spec *) p;
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const int l = strlen (spec->name);
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return substring_hash (spec->name, l);
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}
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/* Used for attribute_hash. */
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static int
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eq_attr (const void *p, const void *q)
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{
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const struct attribute_spec *const spec = (const struct attribute_spec *) p;
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const struct substring *const str = (const struct substring *) q;
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return (!strncmp (spec->name, str->str, str->length) && !spec->name[str->length]);
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}
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/* Initialize attribute tables, and make some sanity checks
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if --enable-checking. */
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static void
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init_attributes (void)
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{
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size_t i;
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int k;
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attribute_tables[0] = lang_hooks.common_attribute_table;
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attribute_tables[1] = lang_hooks.attribute_table;
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attribute_tables[2] = lang_hooks.format_attribute_table;
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attribute_tables[3] = targetm.attribute_table;
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/* Translate NULL pointers to pointers to the empty table. */
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for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
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if (attribute_tables[i] == NULL)
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attribute_tables[i] = empty_attribute_table;
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#ifdef ENABLE_CHECKING
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/* Make some sanity checks on the attribute tables. */
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for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
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{
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int j;
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for (j = 0; attribute_tables[i][j].name != NULL; j++)
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{
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/* The name must not begin and end with __. */
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const char *name = attribute_tables[i][j].name;
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int len = strlen (name);
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gcc_assert (!(name[0] == '_' && name[1] == '_'
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&& name[len - 1] == '_' && name[len - 2] == '_'));
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/* The minimum and maximum lengths must be consistent. */
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gcc_assert (attribute_tables[i][j].min_length >= 0);
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gcc_assert (attribute_tables[i][j].max_length == -1
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|| (attribute_tables[i][j].max_length
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>= attribute_tables[i][j].min_length));
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/* An attribute cannot require both a DECL and a TYPE. */
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gcc_assert (!attribute_tables[i][j].decl_required
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|| !attribute_tables[i][j].type_required);
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/* If an attribute requires a function type, in particular
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it requires a type. */
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gcc_assert (!attribute_tables[i][j].function_type_required
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|| attribute_tables[i][j].type_required);
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}
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}
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/* Check that each name occurs just once in each table. */
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for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
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{
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int j, k;
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for (j = 0; attribute_tables[i][j].name != NULL; j++)
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for (k = j + 1; attribute_tables[i][k].name != NULL; k++)
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gcc_assert (strcmp (attribute_tables[i][j].name,
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attribute_tables[i][k].name));
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}
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/* Check that no name occurs in more than one table. */
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for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
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{
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size_t j, k, l;
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for (j = i + 1; j < ARRAY_SIZE (attribute_tables); j++)
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for (k = 0; attribute_tables[i][k].name != NULL; k++)
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for (l = 0; attribute_tables[j][l].name != NULL; l++)
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gcc_assert (strcmp (attribute_tables[i][k].name,
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attribute_tables[j][l].name));
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}
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#endif
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attribute_hash = htab_create (200, hash_attr, eq_attr, NULL);
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for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
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for (k = 0; attribute_tables[i][k].name != NULL; k++)
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{
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register_attribute (&attribute_tables[i][k]);
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}
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invoke_plugin_callbacks (PLUGIN_ATTRIBUTES, NULL);
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attributes_initialized = true;
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}
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/* Insert a single ATTR into the attribute table. */
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void
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register_attribute (const struct attribute_spec *attr)
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{
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struct substring str;
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void **slot;
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str.str = attr->name;
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str.length = strlen (str.str);
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slot = htab_find_slot_with_hash (attribute_hash, &str,
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substring_hash (str.str, str.length),
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INSERT);
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gcc_assert (!*slot);
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*slot = (void *) CONST_CAST (struct attribute_spec *, attr);
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}
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/* Return the spec for the attribute named NAME. */
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const struct attribute_spec *
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lookup_attribute_spec (tree name)
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{
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struct substring attr;
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attr.str = IDENTIFIER_POINTER (name);
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attr.length = IDENTIFIER_LENGTH (name);
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extract_attribute_substring (&attr);
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return (const struct attribute_spec *)
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htab_find_with_hash (attribute_hash, &attr,
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substring_hash (attr.str, attr.length));
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}
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/* Process the attributes listed in ATTRIBUTES and install them in *NODE,
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which is either a DECL (including a TYPE_DECL) or a TYPE. If a DECL,
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it should be modified in place; if a TYPE, a copy should be created
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unless ATTR_FLAG_TYPE_IN_PLACE is set in FLAGS. FLAGS gives further
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information, in the form of a bitwise OR of flags in enum attribute_flags
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from tree.h. Depending on these flags, some attributes may be
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returned to be applied at a later stage (for example, to apply
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a decl attribute to the declaration rather than to its type). */
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tree
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decl_attributes (tree *node, tree attributes, int flags)
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{
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tree a;
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tree returned_attrs = NULL_TREE;
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if (TREE_TYPE (*node) == error_mark_node)
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return NULL_TREE;
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if (!attributes_initialized)
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init_attributes ();
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/* If this is a function and the user used #pragma GCC optimize, add the
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options to the attribute((optimize(...))) list. */
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if (TREE_CODE (*node) == FUNCTION_DECL && current_optimize_pragma)
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{
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tree cur_attr = lookup_attribute ("optimize", attributes);
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tree opts = copy_list (current_optimize_pragma);
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if (! cur_attr)
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attributes
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= tree_cons (get_identifier ("optimize"), opts, attributes);
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else
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TREE_VALUE (cur_attr) = chainon (opts, TREE_VALUE (cur_attr));
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}
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if (TREE_CODE (*node) == FUNCTION_DECL
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&& optimization_current_node != optimization_default_node
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&& !DECL_FUNCTION_SPECIFIC_OPTIMIZATION (*node))
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DECL_FUNCTION_SPECIFIC_OPTIMIZATION (*node) = optimization_current_node;
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/* If this is a function and the user used #pragma GCC target, add the
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options to the attribute((target(...))) list. */
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if (TREE_CODE (*node) == FUNCTION_DECL
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&& current_target_pragma
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&& targetm.target_option.valid_attribute_p (*node, NULL_TREE,
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current_target_pragma, 0))
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{
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tree cur_attr = lookup_attribute ("target", attributes);
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tree opts = copy_list (current_target_pragma);
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if (! cur_attr)
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attributes = tree_cons (get_identifier ("target"), opts, attributes);
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else
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TREE_VALUE (cur_attr) = chainon (opts, TREE_VALUE (cur_attr));
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}
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targetm.insert_attributes (*node, &attributes);
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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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tree args = TREE_VALUE (a);
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tree *anode = node;
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const struct attribute_spec *spec = lookup_attribute_spec (name);
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bool no_add_attrs = 0;
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int fn_ptr_quals = 0;
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tree fn_ptr_tmp = NULL_TREE;
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if (spec == NULL)
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{
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warning (OPT_Wattributes, "%qE attribute directive ignored",
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name);
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continue;
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}
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else if (list_length (args) < spec->min_length
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|| (spec->max_length >= 0
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&& list_length (args) > spec->max_length))
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{
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error ("wrong number of arguments specified for %qE attribute",
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name);
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continue;
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}
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gcc_assert (is_attribute_p (spec->name, name));
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if (spec->decl_required && !DECL_P (*anode))
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{
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if (flags & ((int) ATTR_FLAG_DECL_NEXT
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| (int) ATTR_FLAG_FUNCTION_NEXT
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| (int) ATTR_FLAG_ARRAY_NEXT))
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{
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/* Pass on this attribute to be tried again. */
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returned_attrs = tree_cons (name, args, returned_attrs);
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continue;
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}
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else
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{
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warning (OPT_Wattributes, "%qE attribute does not apply to types",
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name);
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continue;
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}
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}
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/* If we require a type, but were passed a decl, set up to make a
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new type and update the one in the decl. ATTR_FLAG_TYPE_IN_PLACE
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would have applied if we'd been passed a type, but we cannot modify
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the decl's type in place here. */
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if (spec->type_required && DECL_P (*anode))
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{
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anode = &TREE_TYPE (*anode);
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/* Allow ATTR_FLAG_TYPE_IN_PLACE for the type's naming decl. */
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if (!(TREE_CODE (*anode) == TYPE_DECL
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&& *anode == TYPE_NAME (TYPE_MAIN_VARIANT
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(TREE_TYPE (*anode)))))
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flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
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}
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if (spec->function_type_required && TREE_CODE (*anode) != FUNCTION_TYPE
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&& TREE_CODE (*anode) != METHOD_TYPE)
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{
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if (TREE_CODE (*anode) == POINTER_TYPE
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&& (TREE_CODE (TREE_TYPE (*anode)) == FUNCTION_TYPE
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|| TREE_CODE (TREE_TYPE (*anode)) == METHOD_TYPE))
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{
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/* OK, this is a bit convoluted. We can't just make a copy
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of the pointer type and modify its TREE_TYPE, because if
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we change the attributes of the target type the pointer
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type needs to have a different TYPE_MAIN_VARIANT. So we
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pull out the target type now, frob it as appropriate, and
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rebuild the pointer type later.
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This would all be simpler if attributes were part of the
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declarator, grumble grumble. */
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fn_ptr_tmp = TREE_TYPE (*anode);
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fn_ptr_quals = TYPE_QUALS (*anode);
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anode = &fn_ptr_tmp;
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flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
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}
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else if (flags & (int) ATTR_FLAG_FUNCTION_NEXT)
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{
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/* Pass on this attribute to be tried again. */
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returned_attrs = tree_cons (name, args, returned_attrs);
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continue;
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}
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if (TREE_CODE (*anode) != FUNCTION_TYPE
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&& TREE_CODE (*anode) != METHOD_TYPE)
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{
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warning (OPT_Wattributes,
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"%qE attribute only applies to function types",
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name);
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continue;
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}
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}
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if (TYPE_P (*anode)
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&& (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
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&& TYPE_SIZE (*anode) != NULL_TREE)
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{
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warning (OPT_Wattributes, "type attributes ignored after type is already defined");
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continue;
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}
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if (spec->handler != NULL)
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returned_attrs = chainon ((*spec->handler) (anode, name, args,
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flags, &no_add_attrs),
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returned_attrs);
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/* Layout the decl in case anything changed. */
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if (spec->type_required && DECL_P (*node)
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&& (TREE_CODE (*node) == VAR_DECL
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|| TREE_CODE (*node) == PARM_DECL
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|| TREE_CODE (*node) == RESULT_DECL))
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relayout_decl (*node);
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if (!no_add_attrs)
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{
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tree old_attrs;
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tree a;
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if (DECL_P (*anode))
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old_attrs = DECL_ATTRIBUTES (*anode);
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else
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old_attrs = TYPE_ATTRIBUTES (*anode);
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for (a = lookup_attribute (spec->name, old_attrs);
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a != NULL_TREE;
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a = lookup_attribute (spec->name, TREE_CHAIN (a)))
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{
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if (simple_cst_equal (TREE_VALUE (a), args) == 1)
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break;
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}
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if (a == NULL_TREE)
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{
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/* This attribute isn't already in the list. */
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if (DECL_P (*anode))
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DECL_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
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else if (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
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{
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TYPE_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
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/* If this is the main variant, also push the attributes
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out to the other variants. */
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if (*anode == TYPE_MAIN_VARIANT (*anode))
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{
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tree variant;
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for (variant = *anode; variant;
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variant = TYPE_NEXT_VARIANT (variant))
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{
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if (TYPE_ATTRIBUTES (variant) == old_attrs)
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TYPE_ATTRIBUTES (variant)
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= TYPE_ATTRIBUTES (*anode);
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else if (!lookup_attribute
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(spec->name, TYPE_ATTRIBUTES (variant)))
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TYPE_ATTRIBUTES (variant) = tree_cons
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(name, args, TYPE_ATTRIBUTES (variant));
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}
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}
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}
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else
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*anode = build_type_attribute_variant (*anode,
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tree_cons (name, args,
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old_attrs));
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}
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}
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if (fn_ptr_tmp)
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{
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/* Rebuild the function pointer type and put it in the
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appropriate place. */
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fn_ptr_tmp = build_pointer_type (fn_ptr_tmp);
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if (fn_ptr_quals)
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fn_ptr_tmp = build_qualified_type (fn_ptr_tmp, fn_ptr_quals);
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if (DECL_P (*node))
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TREE_TYPE (*node) = fn_ptr_tmp;
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else
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{
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gcc_assert (TREE_CODE (*node) == POINTER_TYPE);
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*node = fn_ptr_tmp;
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}
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}
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}
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return returned_attrs;
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}
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