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freebsd/contrib/gcc/c-pragma.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
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 "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-lex.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)
#ifdef HANDLE_PRAGMA_PACK
static void handle_pragma_pack PARAMS ((cpp_reader *));
#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
typedef struct align_stack
{
int alignment;
unsigned int num_pushes;
tree id;
struct align_stack * prev;
} align_stack;
static struct align_stack * alignment_stack = NULL;
/* 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 PARAMS ((int, tree));
static void pop_alignment PARAMS ((tree));
static void mark_align_stack PARAMS ((void *));
/* Push an alignment value onto the stack. */
static void
push_alignment (alignment, id)
int alignment;
tree id;
{
if (alignment_stack == NULL
|| alignment_stack->alignment != alignment
|| id != NULL_TREE)
{
align_stack * entry;
entry = (align_stack *) xmalloc (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 (id)
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;
free (alignment_stack);
alignment_stack = entry;
}
}
static void
mark_align_stack (p)
void *p;
{
align_stack *a = *(align_stack **) p;
while (a)
{
ggc_mark_tree (a->id);
a = a->prev;
}
}
#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 (dummy)
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 */
#ifdef HANDLE_PRAGMA_WEAK
static void apply_pragma_weak PARAMS ((tree, tree));
static void handle_pragma_weak PARAMS ((cpp_reader *));
static tree pending_weaks;
static void
apply_pragma_weak (decl, value)
tree decl, value;
{
if (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)
&& TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
warning_with_decl (decl, "applying #pragma weak `%s' after first use results in unspecified behavior");
declare_weak (decl);
}
void
maybe_apply_pragma_weak (decl)
tree decl;
{
tree *p, t, id;
/* 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))))
id = DECL_ASSEMBLER_NAME (decl);
else
return;
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 (dummy)
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);
else
pending_weaks = tree_cons (name, value, pending_weaks);
}
#else
void
maybe_apply_pragma_weak (decl)
tree decl ATTRIBUTE_UNUSED;
{
}
#endif /* HANDLE_PRAGMA_WEAK */
#ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
static void handle_pragma_redefine_extname PARAMS ((cpp_reader *));
static tree pending_redefine_extname;
/* #pragma redefined_extname oldname newname */
static void
handle_pragma_redefine_extname (dummy)
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_CLASS (TREE_CODE (decl)) == 'd')
{
if (DECL_ASSEMBLER_NAME_SET_P (decl)
&& DECL_ASSEMBLER_NAME (decl) != newname)
warning ("#pragma redefine_extname conflicts with declaration");
SET_DECL_ASSEMBLER_NAME (decl, newname);
}
else
pending_redefine_extname
= tree_cons (oldname, newname, pending_redefine_extname);
}
#endif
#ifdef HANDLE_PRAGMA_EXTERN_PREFIX
static void handle_pragma_extern_prefix PARAMS ((cpp_reader *));
static tree pragma_extern_prefix;
/* #pragma extern_prefix "prefix" */
static void
handle_pragma_extern_prefix (dummy)
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 preceeding
pragmas that rename variables. */
tree
maybe_apply_renaming_pragma (decl, asmname)
tree decl, 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 conficts with previous rename");
asmname = build_string (strlen (oldasmname), oldasmname);
}
#ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
{
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);
}
}
#endif
#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;
}
void
init_pragma ()
{
#ifdef HANDLE_PRAGMA_PACK
cpp_register_pragma (parse_in, 0, "pack", handle_pragma_pack);
#endif
#ifdef HANDLE_PRAGMA_WEAK
cpp_register_pragma (parse_in, 0, "weak", handle_pragma_weak);
ggc_add_tree_root (&pending_weaks, 1);
#endif
#ifdef HANDLE_PRAGMA_REDEFINE_EXTNAME
cpp_register_pragma (parse_in, 0, "redefine_extname",
handle_pragma_redefine_extname);
ggc_add_tree_root (&pending_redefine_extname, 1);
#endif
#ifdef HANDLE_PRAGMA_EXTERN_PREFIX
cpp_register_pragma (parse_in, 0, "extern_prefix",
handle_pragma_extern_prefix);
ggc_add_tree_root (&pragma_extern_prefix, 1);
#endif
#ifdef REGISTER_TARGET_PRAGMAS
REGISTER_TARGET_PRAGMAS (parse_in);
#endif
#ifdef HANDLE_PRAGMA_PACK_PUSH_POP
ggc_add_root (&alignment_stack, 1, sizeof(alignment_stack),
mark_align_stack);
#endif
}
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