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freebsd/contrib/gcc/c-pragma.c
Alexander Kabaev 9a63ad9273 Gcc 3.4.2 20040728.
2004-07-28 03:11:36 +00:00

516 lines
13 KiB
C
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/* Handle #pragma, system V.4 style. Supports #pragma weak and #pragma pack.
Copyright (C) 1992, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
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, 59 Temple Place - Suite 330, Boston, MA
02111-1307, USA. */
#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "tree.h"
#include "function.h"
#include "cpplib.h"
#include "c-pragma.h"
#include "flags.h"
#include "toplev.h"
#include "ggc.h"
#include "c-common.h"
#include "output.h"
#include "tm_p.h"
#define GCC_BAD(msgid) do { warning (msgid); return; } while (0)
#define GCC_BAD2(msgid, arg) do { warning (msgid, arg); return; } while (0)
typedef struct align_stack GTY(())
{
int alignment;
unsigned int num_pushes;
tree id;
struct align_stack * prev;
} align_stack;
static GTY(()) struct align_stack * alignment_stack;
#ifdef HANDLE_PRAGMA_PACK
static void handle_pragma_pack (cpp_reader *);
#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
/* If we have a "global" #pragma pack(<n>) in effect when the first
#pragma pack(push,<n>) is encountered, this stores the value of
maximum_field_alignment in effect. When the final pop_alignment()
happens, we restore the value to this, not to a value of 0 for
maximum_field_alignment. Value is in bits. */
static int default_alignment;
#define SET_GLOBAL_ALIGNMENT(ALIGN) \
(default_alignment = maximum_field_alignment = (ALIGN))
static void push_alignment (int, tree);
static void pop_alignment (tree);
/* Push an alignment value onto the stack. */
static void
push_alignment (int alignment, tree id)
{
if (alignment_stack == NULL
|| alignment_stack->alignment != alignment
|| id != NULL_TREE)
{
align_stack * entry;
entry = ggc_alloc (sizeof (* entry));
entry->alignment = alignment;
entry->num_pushes = 1;
entry->id = id;
entry->prev = alignment_stack;
/* The current value of maximum_field_alignment is not necessarily
0 since there may be a #pragma pack(<n>) in effect; remember it
so that we can restore it after the final #pragma pop(). */
if (alignment_stack == NULL)
default_alignment = maximum_field_alignment;
alignment_stack = entry;
maximum_field_alignment = alignment;
}
else
alignment_stack->num_pushes ++;
}
/* Undo a push of an alignment onto the stack. */
static void
pop_alignment (tree id)
{
align_stack * entry;
if (alignment_stack == NULL)
{
warning ("\
#pragma pack (pop) encountered without matching #pragma pack (push, <n>)"
);
return;
}
/* If we got an identifier, strip away everything above the target
entry so that the next step will restore the state just below it. */
if (id)
{
for (entry = alignment_stack; entry; entry = entry->prev)
if (entry->id == id)
{
entry->num_pushes = 1;
alignment_stack = entry;
break;
}
if (entry == NULL)
warning ("\
#pragma pack(pop, %s) encountered without matching #pragma pack(push, %s, <n>)"
, IDENTIFIER_POINTER (id), IDENTIFIER_POINTER (id));
}
if (-- alignment_stack->num_pushes == 0)
{
entry = alignment_stack->prev;
if (entry == NULL)
maximum_field_alignment = default_alignment;
else
maximum_field_alignment = entry->alignment;
alignment_stack = entry;
}
}
#else /* not HANDLE_PRAGMA_PACK_PUSH_POP */
#define SET_GLOBAL_ALIGNMENT(ALIGN) (maximum_field_alignment = (ALIGN))
#define push_alignment(ID, N) \
GCC_BAD("#pragma pack(push[, id], <n>) is not supported on this target")
#define pop_alignment(ID) \
GCC_BAD("#pragma pack(pop[, id], <n>) is not supported on this target")
#endif /* HANDLE_PRAGMA_PACK_PUSH_POP */
/* #pragma pack ()
#pragma pack (N)
#pragma pack (push, N)
#pragma pack (push, ID, N)
#pragma pack (pop)
#pragma pack (pop, ID) */
static void
handle_pragma_pack (cpp_reader *dummy ATTRIBUTE_UNUSED)
{
tree x, id = 0;
int align = -1;
enum cpp_ttype token;
enum { set, push, pop } action;
if (c_lex (&x) != CPP_OPEN_PAREN)
GCC_BAD ("missing '(' after '#pragma pack' - ignored");
token = c_lex (&x);
if (token == CPP_CLOSE_PAREN)
{
action = set;
align = 0;
}
else if (token == CPP_NUMBER)
{
align = TREE_INT_CST_LOW (x);
action = set;
if (c_lex (&x) != CPP_CLOSE_PAREN)
GCC_BAD ("malformed '#pragma pack' - ignored");
}
else if (token == CPP_NAME)
{
#define GCC_BAD_ACTION do { if (action == push) \
GCC_BAD ("malformed '#pragma pack(push[, id], <n>)' - ignored"); \
else \
GCC_BAD ("malformed '#pragma pack(pop[, id])' - ignored"); \
} while (0)
const char *op = IDENTIFIER_POINTER (x);
if (!strcmp (op, "push"))
action = push;
else if (!strcmp (op, "pop"))
action = pop;
else
GCC_BAD2 ("unknown action '%s' for '#pragma pack' - ignored", op);
token = c_lex (&x);
if (token != CPP_COMMA && action == push)
GCC_BAD_ACTION;
if (token == CPP_COMMA)
{
token = c_lex (&x);
if (token == CPP_NAME)
{
id = x;
if (action == push && c_lex (&x) != CPP_COMMA)
GCC_BAD_ACTION;
token = c_lex (&x);
}
if (action == push)
{
if (token == CPP_NUMBER)
{
align = TREE_INT_CST_LOW (x);
token = c_lex (&x);
}
else
GCC_BAD_ACTION;
}
}
if (token != CPP_CLOSE_PAREN)
GCC_BAD_ACTION;
#undef GCC_BAD_ACTION
}
else
GCC_BAD ("malformed '#pragma pack' - ignored");
if (c_lex (&x) != CPP_EOF)
warning ("junk at end of '#pragma pack'");
if (action != pop)
switch (align)
{
case 0:
case 1:
case 2:
case 4:
case 8:
case 16:
align *= BITS_PER_UNIT;
break;
default:
GCC_BAD2 ("alignment must be a small power of two, not %d", align);
}
switch (action)
{
case set: SET_GLOBAL_ALIGNMENT (align); break;
case push: push_alignment (align, id); break;
case pop: pop_alignment (id); break;
}
}
#endif /* HANDLE_PRAGMA_PACK */
static GTY(()) tree pending_weaks;
#ifdef HANDLE_PRAGMA_WEAK
static void apply_pragma_weak (tree, tree);
static void handle_pragma_weak (cpp_reader *);
static void
apply_pragma_weak (tree decl, tree value)
{
if (value)
{
value = build_string (IDENTIFIER_LENGTH (value),
IDENTIFIER_POINTER (value));
decl_attributes (&decl, build_tree_list (get_identifier ("alias"),
build_tree_list (NULL, value)),
0);
}
if (SUPPORTS_WEAK && DECL_EXTERNAL (decl) && TREE_USED (decl)
&& !DECL_WEAK (decl) /* Don't complain about a redundant #pragma. */
&& TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
warning ("%Japplying #pragma weak '%D' after first use results "
"in unspecified behavior", decl, decl);
declare_weak (decl);
}
void
maybe_apply_pragma_weak (tree decl)
{
tree *p, t, id;
/* Avoid asking for DECL_ASSEMBLER_NAME when it's not needed. */
/* No weak symbols pending, take the short-cut. */
if (!pending_weaks)
return;
/* If it's not visible outside this file, it doesn't matter whether
it's weak. */
if (!DECL_EXTERNAL (decl) && !TREE_PUBLIC (decl))
return;
/* If it's not a function or a variable, it can't be weak.
FIXME: what kinds of things are visible outside this file but
aren't functions or variables? Should this be an abort() instead? */
if (TREE_CODE (decl) != FUNCTION_DECL && TREE_CODE (decl) != VAR_DECL)
return;
id = DECL_ASSEMBLER_NAME (decl);
for (p = &pending_weaks; (t = *p) ; p = &TREE_CHAIN (t))
if (id == TREE_PURPOSE (t))
{
apply_pragma_weak (decl, TREE_VALUE (t));
*p = TREE_CHAIN (t);
break;
}
}
/* #pragma weak name [= value] */
static void
handle_pragma_weak (cpp_reader *dummy ATTRIBUTE_UNUSED)
{
tree name, value, x, decl;
enum cpp_ttype t;
value = 0;
if (c_lex (&name) != CPP_NAME)
GCC_BAD ("malformed #pragma weak, ignored");
t = c_lex (&x);
if (t == CPP_EQ)
{
if (c_lex (&value) != CPP_NAME)
GCC_BAD ("malformed #pragma weak, ignored");
t = c_lex (&x);
}
if (t != CPP_EOF)
warning ("junk at end of #pragma weak");
decl = identifier_global_value (name);
if (decl && TREE_CODE_CLASS (TREE_CODE (decl)) == 'd')
{
apply_pragma_weak (decl, value);
if (value)
assemble_alias (decl, value);
}
else
pending_weaks = tree_cons (name, value, pending_weaks);
}
#else
void
maybe_apply_pragma_weak (tree decl ATTRIBUTE_UNUSED)
{
}
#endif /* HANDLE_PRAGMA_WEAK */
static GTY(()) tree pending_redefine_extname;
#ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
static void handle_pragma_redefine_extname (cpp_reader *);
/* #pragma redefined_extname oldname newname */
static void
handle_pragma_redefine_extname (cpp_reader *dummy ATTRIBUTE_UNUSED)
{
tree oldname, newname, decl, x;
enum cpp_ttype t;
if (c_lex (&oldname) != CPP_NAME)
{
warning ("malformed #pragma redefine_extname, ignored");
return;
}
if (c_lex (&newname) != CPP_NAME)
{
warning ("malformed #pragma redefine_extname, ignored");
return;
}
t = c_lex (&x);
if (t != CPP_EOF)
warning ("junk at end of #pragma redefine_extname");
decl = identifier_global_value (oldname);
if (decl && (TREE_CODE (decl) == FUNCTION_DECL
|| TREE_CODE (decl) == VAR_DECL))
{
if (DECL_ASSEMBLER_NAME_SET_P (decl)
&& DECL_ASSEMBLER_NAME (decl) != newname)
warning ("#pragma redefine_extname conflicts with declaration");
change_decl_assembler_name (decl, newname);
}
else
add_to_renaming_pragma_list(oldname, newname);
}
#endif
void
add_to_renaming_pragma_list (tree oldname, tree newname)
{
pending_redefine_extname
= tree_cons (oldname, newname, pending_redefine_extname);
}
static GTY(()) tree pragma_extern_prefix;
#ifdef HANDLE_PRAGMA_EXTERN_PREFIX
static void handle_pragma_extern_prefix (cpp_reader *);
/* #pragma extern_prefix "prefix" */
static void
handle_pragma_extern_prefix (cpp_reader *dummy ATTRIBUTE_UNUSED)
{
tree prefix, x;
enum cpp_ttype t;
if (c_lex (&prefix) != CPP_STRING)
{
warning ("malformed #pragma extern_prefix, ignored");
return;
}
t = c_lex (&x);
if (t != CPP_EOF)
warning ("junk at end of #pragma extern_prefix");
/* Note that the length includes the null terminator. */
pragma_extern_prefix = (TREE_STRING_LENGTH (prefix) > 1 ? prefix : NULL);
}
#endif
/* Hook from the front ends to apply the results of one of the preceding
pragmas that rename variables. */
tree
maybe_apply_renaming_pragma (tree decl, tree asmname)
{
tree oldname;
/* Copied from the check in set_decl_assembler_name. */
if (TREE_CODE (decl) == FUNCTION_DECL
|| (TREE_CODE (decl) == VAR_DECL
&& (TREE_STATIC (decl)
|| DECL_EXTERNAL (decl)
|| TREE_PUBLIC (decl))))
oldname = DECL_ASSEMBLER_NAME (decl);
else
return asmname;
/* If the name begins with a *, that's a sign of an asmname attached to
a previous declaration. */
if (IDENTIFIER_POINTER (oldname)[0] == '*')
{
const char *oldasmname = IDENTIFIER_POINTER (oldname) + 1;
if (asmname && strcmp (TREE_STRING_POINTER (asmname), oldasmname) != 0)
warning ("asm declaration conflicts with previous rename");
asmname = build_string (strlen (oldasmname), oldasmname);
}
{
tree *p, t;
for (p = &pending_redefine_extname; (t = *p) ; p = &TREE_CHAIN (t))
if (oldname == TREE_PURPOSE (t))
{
const char *newname = IDENTIFIER_POINTER (TREE_VALUE (t));
if (asmname && strcmp (TREE_STRING_POINTER (asmname), newname) != 0)
warning ("#pragma redefine_extname conflicts with declaration");
*p = TREE_CHAIN (t);
return build_string (strlen (newname), newname);
}
}
#ifdef HANDLE_PRAGMA_EXTERN_PREFIX
if (pragma_extern_prefix && !asmname)
{
char *x = concat (TREE_STRING_POINTER (pragma_extern_prefix),
IDENTIFIER_POINTER (oldname), NULL);
asmname = build_string (strlen (x), x);
free (x);
return asmname;
}
#endif
return asmname;
}
/* Front-end wrapper for pragma registration to avoid dragging
cpplib.h in almost everywhere. */
void
c_register_pragma (const char *space, const char *name,
void (*handler) (struct cpp_reader *))
{
cpp_register_pragma (parse_in, space, name, handler);
}
/* Set up front-end pragmas. */
void
init_pragma (void)
{
#ifdef HANDLE_PRAGMA_PACK
c_register_pragma (0, "pack", handle_pragma_pack);
#endif
#ifdef HANDLE_PRAGMA_WEAK
c_register_pragma (0, "weak", handle_pragma_weak);
#endif
#ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
c_register_pragma (0, "redefine_extname", handle_pragma_redefine_extname);
#endif
#ifdef HANDLE_PRAGMA_EXTERN_PREFIX
c_register_pragma (0, "extern_prefix", handle_pragma_extern_prefix);
#endif
#ifdef REGISTER_TARGET_PRAGMAS
REGISTER_TARGET_PRAGMAS ();
#endif
}
#include "gt-c-pragma.h"
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