232 lines
7.3 KiB
C
232 lines
7.3 KiB
C
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/* Control and data flow functions for trees.
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Copyright 2001, 2002, 2003, 2004 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
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GCC is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License 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
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the Free Software Foundation, 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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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 "toplev.h"
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#include "tree.h"
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#include "tree-inline.h"
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#include "flags.h"
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#include "langhooks.h"
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#include "cgraph.h"
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#include "timevar.h"
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#include "tm.h"
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#include "function.h"
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#include "ggc.h"
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/* Called to move the SAVE_EXPRs for parameter declarations in a
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nested function into the nested function. DATA is really the
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nested FUNCTION_DECL. */
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static tree
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set_save_expr_context (tree *tp,
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int *walk_subtrees,
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void *data)
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{
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if (TREE_CODE (*tp) == SAVE_EXPR && !SAVE_EXPR_CONTEXT (*tp))
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SAVE_EXPR_CONTEXT (*tp) = (tree) data;
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/* Do not walk back into the SAVE_EXPR_CONTEXT; that will cause
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circularity. */
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else if (DECL_P (*tp))
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*walk_subtrees = 0;
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return NULL;
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}
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/* Clear out the DECL_RTL for the non-static local variables in BLOCK and
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its sub-blocks. DATA is the decl of the function being processed. */
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static tree
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clear_decl_rtl (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED, void *data)
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{
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bool nonstatic_p, local_p;
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tree t = *tp;
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switch (TREE_CODE (t))
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{
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case VAR_DECL:
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nonstatic_p = !TREE_STATIC (t) && !DECL_EXTERNAL (t);
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local_p = decl_function_context (t) == data;
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break;
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case PARM_DECL:
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case LABEL_DECL:
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nonstatic_p = true;
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local_p = decl_function_context (t) == data;
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break;
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case RESULT_DECL:
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nonstatic_p = local_p = true;
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break;
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default:
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nonstatic_p = local_p = false;
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break;
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}
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if (nonstatic_p && local_p)
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SET_DECL_RTL (t, NULL);
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return NULL;
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}
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/* For functions-as-trees languages, this performs all optimization and
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compilation for FNDECL. */
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void
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tree_rest_of_compilation (tree fndecl, bool nested_p)
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{
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location_t saved_loc;
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timevar_push (TV_EXPAND);
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if (flag_unit_at_a_time && !cgraph_global_info_ready)
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abort ();
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/* Initialize the RTL code for the function. */
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current_function_decl = fndecl;
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saved_loc = input_location;
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input_location = DECL_SOURCE_LOCATION (fndecl);
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init_function_start (fndecl);
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/* This function is being processed in whole-function mode. */
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cfun->x_whole_function_mode_p = 1;
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/* Even though we're inside a function body, we still don't want to
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call expand_expr to calculate the size of a variable-sized array.
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We haven't necessarily assigned RTL to all variables yet, so it's
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not safe to try to expand expressions involving them. */
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immediate_size_expand = 0;
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cfun->x_dont_save_pending_sizes_p = 1;
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/* If the function has a variably modified type, there may be
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SAVE_EXPRs in the parameter types. Their context must be set to
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refer to this function; they cannot be expanded in the containing
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function. */
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if (decl_function_context (fndecl)
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&& variably_modified_type_p (TREE_TYPE (fndecl)))
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walk_tree (&TREE_TYPE (fndecl), set_save_expr_context, fndecl,
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NULL);
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/* Set up parameters and prepare for return, for the function. */
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expand_function_start (fndecl, 0);
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/* Allow language dialects to perform special processing. */
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(*lang_hooks.rtl_expand.start) ();
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/* If this function is `main', emit a call to `__main'
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to run global initializers, etc. */
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if (DECL_NAME (fndecl)
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&& MAIN_NAME_P (DECL_NAME (fndecl))
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&& DECL_FILE_SCOPE_P (fndecl))
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expand_main_function ();
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/* Generate the RTL for this function. */
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(*lang_hooks.rtl_expand.stmt) (DECL_SAVED_TREE (fndecl));
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/* We hard-wired immediate_size_expand to zero above.
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expand_function_end will decrement this variable. So, we set the
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variable to one here, so that after the decrement it will remain
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zero. */
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immediate_size_expand = 1;
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/* Allow language dialects to perform special processing. */
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(*lang_hooks.rtl_expand.end) ();
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/* Generate rtl for function exit. */
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expand_function_end ();
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/* If this is a nested function, protect the local variables in the stack
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above us from being collected while we're compiling this function. */
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if (nested_p)
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ggc_push_context ();
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/* There's no need to defer outputting this function any more; we
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know we want to output it. */
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DECL_DEFER_OUTPUT (fndecl) = 0;
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/* Run the optimizers and output the assembler code for this function. */
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rest_of_compilation (fndecl);
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/* Undo the GC context switch. */
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if (nested_p)
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ggc_pop_context ();
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/* If requested, warn about function definitions where the function will
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return a value (usually of some struct or union type) which itself will
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take up a lot of stack space. */
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if (warn_larger_than && !DECL_EXTERNAL (fndecl) && TREE_TYPE (fndecl))
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{
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tree ret_type = TREE_TYPE (TREE_TYPE (fndecl));
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if (ret_type && TYPE_SIZE_UNIT (ret_type)
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&& TREE_CODE (TYPE_SIZE_UNIT (ret_type)) == INTEGER_CST
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&& 0 < compare_tree_int (TYPE_SIZE_UNIT (ret_type),
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larger_than_size))
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{
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unsigned int size_as_int
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= TREE_INT_CST_LOW (TYPE_SIZE_UNIT (ret_type));
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if (compare_tree_int (TYPE_SIZE_UNIT (ret_type), size_as_int) == 0)
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warning ("%Jsize of return value of '%D' is %u bytes",
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fndecl, fndecl, size_as_int);
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else
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warning ("%Jsize of return value of '%D' is larger than %wd bytes",
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fndecl, fndecl, larger_than_size);
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}
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}
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if (! DECL_DEFER_OUTPUT (fndecl) || !cgraph_node (fndecl)->origin)
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{
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/* Since we don't need the RTL for this function anymore, stop pointing
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to it. That's especially important for LABEL_DECLs, since you can
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reach all the instructions in the function from the CODE_LABEL stored
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in the DECL_RTL for the LABEL_DECL. Walk the BLOCK-tree, clearing
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DECL_RTL for LABEL_DECLs and non-static local variables. Note that
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we must check the context of the variables, otherwise processing a
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nested function can kill the rtl of a variable from an outer
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function. */
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walk_tree_without_duplicates (&DECL_SAVED_TREE (fndecl),
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clear_decl_rtl,
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fndecl);
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if (!cgraph_function_possibly_inlined_p (fndecl))
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{
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DECL_SAVED_TREE (fndecl) = NULL;
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if (DECL_SAVED_INSNS (fndecl) == 0
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&& !cgraph_node (fndecl)->origin)
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{
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/* Stop pointing to the local nodes about to be freed.
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But DECL_INITIAL must remain nonzero so we know this
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was an actual function definition.
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For a nested function, this is done in c_pop_function_context.
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If rest_of_compilation set this to 0, leave it 0. */
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if (DECL_INITIAL (fndecl) != 0)
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DECL_INITIAL (fndecl) = error_mark_node;
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}
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}
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}
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input_location = saved_loc;
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timevar_pop (TV_EXPAND);
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}
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