freebsd-skq/contrib/gcc/attribs.c
pfg fe288f1b72 MFC r260311, r260831:
gcc: Add support for Apple's Block extension

Block objects [1] are a C-level syntactic and runtime feature. They
are similar to standard C functions, but in addition to executable
code they may also contain variable bindings to automatic (stack)
or managed (heap) memory. A block can therefore maintain a set of
state (data) that it can use to impact behavior when executed.

This port is based on Apple's GCC 5646 with some bugfixes from
Apple GCC 5666.3. It has some small differences with the support
in clang, which remains the recommended compiler.

Perhaps the most notable difference is that in GCC __block is not
actually a keyword, but a macro. There may be workaround for this
issue in the future. Other issues can be consulted in the clang
documentation [2]

For better compatiblity with Apple's GCC and llvm-gcc, some related
fixes and features from Apple have been included. Support for the
non-standard nested functions in GCC is now off by default.

No effort was made to update the ObjC support since FreeBSD doesn't
carry ObjC in the base system but some of the code crept in and
was more difficult to remove than to adjust.

References:
[1]
https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Blocks/Articles/00_Introduction.html
[2]
http://clang.llvm.org/compatibility.html#block-variable-initialization

Obtained from:	Apple GCC 4.2
2014-01-26 19:49:54 +00:00

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/* Functions dealing with attribute handling, used by most front ends.
Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "tree.h"
#include "flags.h"
#include "toplev.h"
#include "output.h"
#include "rtl.h"
#include "ggc.h"
#include "tm_p.h"
#include "cpplib.h"
#include "target.h"
#include "langhooks.h"
static void init_attributes (void);
/* Table of the tables of attributes (common, language, format, machine)
searched. */
static const struct attribute_spec *attribute_tables[4];
static bool attributes_initialized = false;
/* Default empty table of attributes. */
static const struct attribute_spec empty_attribute_table[] =
{
{ NULL, 0, 0, false, false, false, NULL }
};
/* Initialize attribute tables, and make some sanity checks
if --enable-checking. */
static void
init_attributes (void)
{
size_t i;
attribute_tables[0] = lang_hooks.common_attribute_table;
attribute_tables[1] = lang_hooks.attribute_table;
attribute_tables[2] = lang_hooks.format_attribute_table;
attribute_tables[3] = targetm.attribute_table;
/* Translate NULL pointers to pointers to the empty table. */
for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
if (attribute_tables[i] == NULL)
attribute_tables[i] = empty_attribute_table;
#ifdef ENABLE_CHECKING
/* Make some sanity checks on the attribute tables. */
for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
{
int j;
for (j = 0; attribute_tables[i][j].name != NULL; j++)
{
/* The name must not begin and end with __. */
const char *name = attribute_tables[i][j].name;
int len = strlen (name);
gcc_assert (!(name[0] == '_' && name[1] == '_'
&& name[len - 1] == '_' && name[len - 2] == '_'));
/* The minimum and maximum lengths must be consistent. */
gcc_assert (attribute_tables[i][j].min_length >= 0);
gcc_assert (attribute_tables[i][j].max_length == -1
|| (attribute_tables[i][j].max_length
>= attribute_tables[i][j].min_length));
/* An attribute cannot require both a DECL and a TYPE. */
gcc_assert (!attribute_tables[i][j].decl_required
|| !attribute_tables[i][j].type_required);
/* If an attribute requires a function type, in particular
it requires a type. */
gcc_assert (!attribute_tables[i][j].function_type_required
|| attribute_tables[i][j].type_required);
}
}
/* Check that each name occurs just once in each table. */
for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
{
int j, k;
for (j = 0; attribute_tables[i][j].name != NULL; j++)
for (k = j + 1; attribute_tables[i][k].name != NULL; k++)
gcc_assert (strcmp (attribute_tables[i][j].name,
attribute_tables[i][k].name));
}
/* Check that no name occurs in more than one table. */
for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
{
size_t j, k, l;
for (j = i + 1; j < ARRAY_SIZE (attribute_tables); j++)
for (k = 0; attribute_tables[i][k].name != NULL; k++)
for (l = 0; attribute_tables[j][l].name != NULL; l++)
gcc_assert (strcmp (attribute_tables[i][k].name,
attribute_tables[j][l].name));
}
#endif
attributes_initialized = true;
}
/* Process the attributes listed in ATTRIBUTES and install them in *NODE,
which is either a DECL (including a TYPE_DECL) or a TYPE. If a DECL,
it should be modified in place; if a TYPE, a copy should be created
unless ATTR_FLAG_TYPE_IN_PLACE is set in FLAGS. FLAGS gives further
information, in the form of a bitwise OR of flags in enum attribute_flags
from tree.h. Depending on these flags, some attributes may be
returned to be applied at a later stage (for example, to apply
a decl attribute to the declaration rather than to its type). */
tree
decl_attributes (tree *node, tree attributes, int flags)
{
tree a;
tree returned_attrs = NULL_TREE;
if (!attributes_initialized)
init_attributes ();
targetm.insert_attributes (*node, &attributes);
for (a = attributes; a; a = TREE_CHAIN (a))
{
tree name = TREE_PURPOSE (a);
tree args = TREE_VALUE (a);
tree *anode = node;
const struct attribute_spec *spec = NULL;
bool no_add_attrs = 0;
tree fn_ptr_tmp = NULL_TREE;
size_t i;
for (i = 0; i < ARRAY_SIZE (attribute_tables); i++)
{
int j;
for (j = 0; attribute_tables[i][j].name != NULL; j++)
{
if (is_attribute_p (attribute_tables[i][j].name, name))
{
spec = &attribute_tables[i][j];
break;
}
}
if (spec != NULL)
break;
}
if (spec == NULL)
{
warning (OPT_Wattributes, "%qs attribute directive ignored",
IDENTIFIER_POINTER (name));
continue;
}
else if (list_length (args) < spec->min_length
|| (spec->max_length >= 0
&& list_length (args) > spec->max_length))
{
error ("wrong number of arguments specified for %qs attribute",
IDENTIFIER_POINTER (name));
continue;
}
if (spec->decl_required && !DECL_P (*anode))
{
if (flags & ((int) ATTR_FLAG_DECL_NEXT
| (int) ATTR_FLAG_FUNCTION_NEXT
| (int) ATTR_FLAG_ARRAY_NEXT))
{
/* Pass on this attribute to be tried again. */
returned_attrs = tree_cons (name, args, returned_attrs);
continue;
}
else
{
warning (OPT_Wattributes, "%qs attribute does not apply to types",
IDENTIFIER_POINTER (name));
continue;
}
}
/* If we require a type, but were passed a decl, set up to make a
new type and update the one in the decl. ATTR_FLAG_TYPE_IN_PLACE
would have applied if we'd been passed a type, but we cannot modify
the decl's type in place here. */
if (spec->type_required && DECL_P (*anode))
{
anode = &TREE_TYPE (*anode);
flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
}
if (spec->function_type_required && TREE_CODE (*anode) != FUNCTION_TYPE
&& TREE_CODE (*anode) != METHOD_TYPE)
{
/* APPLE LOCAL radar 6246527 */
if ((TREE_CODE (*anode) == POINTER_TYPE || TREE_CODE (*anode) == BLOCK_POINTER_TYPE)
&& (TREE_CODE (TREE_TYPE (*anode)) == FUNCTION_TYPE
|| TREE_CODE (TREE_TYPE (*anode)) == METHOD_TYPE))
{
/* OK, this is a bit convoluted. We can't just make a copy
of the pointer type and modify its TREE_TYPE, because if
we change the attributes of the target type the pointer
type needs to have a different TYPE_MAIN_VARIANT. So we
pull out the target type now, frob it as appropriate, and
rebuild the pointer type later.
This would all be simpler if attributes were part of the
declarator, grumble grumble. */
fn_ptr_tmp = TREE_TYPE (*anode);
anode = &fn_ptr_tmp;
flags &= ~(int) ATTR_FLAG_TYPE_IN_PLACE;
}
else if (flags & (int) ATTR_FLAG_FUNCTION_NEXT)
{
/* Pass on this attribute to be tried again. */
returned_attrs = tree_cons (name, args, returned_attrs);
continue;
}
if (TREE_CODE (*anode) != FUNCTION_TYPE
&& TREE_CODE (*anode) != METHOD_TYPE)
{
warning (OPT_Wattributes,
"%qs attribute only applies to function types",
IDENTIFIER_POINTER (name));
continue;
}
}
if (TYPE_P (*anode)
&& (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
&& TYPE_SIZE (*anode) != NULL_TREE)
{
warning (OPT_Wattributes, "type attributes ignored after type is already defined");
continue;
}
if (spec->handler != NULL)
returned_attrs = chainon ((*spec->handler) (anode, name, args,
flags, &no_add_attrs),
returned_attrs);
/* Layout the decl in case anything changed. */
if (spec->type_required && DECL_P (*node)
&& (TREE_CODE (*node) == VAR_DECL
|| TREE_CODE (*node) == PARM_DECL
|| TREE_CODE (*node) == RESULT_DECL))
relayout_decl (*node);
if (!no_add_attrs)
{
tree old_attrs;
tree a;
if (DECL_P (*anode))
old_attrs = DECL_ATTRIBUTES (*anode);
else
old_attrs = TYPE_ATTRIBUTES (*anode);
for (a = lookup_attribute (spec->name, old_attrs);
a != NULL_TREE;
a = lookup_attribute (spec->name, TREE_CHAIN (a)))
{
if (simple_cst_equal (TREE_VALUE (a), args) == 1)
break;
}
if (a == NULL_TREE)
{
/* This attribute isn't already in the list. */
if (DECL_P (*anode))
DECL_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
else if (flags & (int) ATTR_FLAG_TYPE_IN_PLACE)
{
TYPE_ATTRIBUTES (*anode) = tree_cons (name, args, old_attrs);
/* If this is the main variant, also push the attributes
out to the other variants. */
if (*anode == TYPE_MAIN_VARIANT (*anode))
{
tree variant;
for (variant = *anode; variant;
variant = TYPE_NEXT_VARIANT (variant))
{
if (TYPE_ATTRIBUTES (variant) == old_attrs)
TYPE_ATTRIBUTES (variant)
= TYPE_ATTRIBUTES (*anode);
else if (!lookup_attribute
(spec->name, TYPE_ATTRIBUTES (variant)))
TYPE_ATTRIBUTES (variant) = tree_cons
(name, args, TYPE_ATTRIBUTES (variant));
}
}
}
else
*anode = build_type_attribute_variant (*anode,
tree_cons (name, args,
old_attrs));
}
}
if (fn_ptr_tmp)
{
/* APPLE LOCAL begin radar 6246527 */
if (DECL_P (*node) && TREE_TYPE (*node) &&
TREE_CODE (TREE_TYPE (*node)) == BLOCK_POINTER_TYPE)
/* Rebuild the block pointer type and put it in the
appropriate place. */
fn_ptr_tmp = build_block_pointer_type (fn_ptr_tmp);
else
/* APPLE LOCAL end radar 6246527 */
/* Rebuild the function pointer type and put it in the
appropriate place. */
fn_ptr_tmp = build_pointer_type (fn_ptr_tmp);
if (DECL_P (*node))
TREE_TYPE (*node) = fn_ptr_tmp;
else
{
gcc_assert (TREE_CODE (*node) == POINTER_TYPE);
*node = fn_ptr_tmp;
}
}
}
return returned_attrs;
}