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