400 lines
12 KiB
C
Executable File
400 lines
12 KiB
C
Executable File
/* Exception Handling interface routines.
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Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc.
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Contributed by Mike Stump <mrs@cygnus.com>.
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This file is part of GNU CC.
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GNU CC 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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GNU CC 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 GNU CC; 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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#if !defined(NULL_RTX) && !defined(rtx)
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typedef struct rtx_def *_except_rtx;
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#define rtx _except_rtx
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#endif
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/* The label generated by expand_builtin_eh_return. */
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extern rtx eh_return_stub_label;
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#ifdef TREE_CODE
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/* A stack of labels. CHAIN points to the next entry in the stack. */
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struct label_node {
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union {
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rtx rlabel;
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tree tlabel;
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} u;
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struct label_node *chain;
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};
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/* An eh_entry is used to describe one exception handling region.
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OUTER_CONTEXT is the label used for rethrowing into the outer context.
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EXCEPTION_HANDLER_LABEL is the label corresponding to the handler
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for this region.
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LABEL_USED indicates whether a CATCH block has already used this
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label or not. New ones are needed for additional catch blocks if
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it has.
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FALSE_LABEL is used when either setjmp/longjmp exceptions are in
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use, or old style table exceptions. It contains the label for
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branching to the next runtime type check as handlers are processed.
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FINALIZATION is the tree codes for the handler, or is NULL_TREE if
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one hasn't been generated yet, or is integer_zero_node to mark the
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end of a group of try blocks. */
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struct eh_entry {
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rtx outer_context;
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rtx exception_handler_label;
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tree finalization;
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int label_used;
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rtx false_label;
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rtx rethrow_label;
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};
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/* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next
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entry in the list, or is NULL if this is the last entry. */
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struct eh_node {
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struct eh_entry *entry;
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struct eh_node *chain;
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};
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/* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is
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NULL if the stack is empty. */
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struct eh_stack {
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struct eh_node *top;
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};
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/* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the
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end (the latest entry). HEAD and TAIL are NULL if the queue is
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empty. */
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struct eh_queue {
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struct eh_node *head;
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struct eh_node *tail;
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};
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/* Start an exception handling region. All instructions emitted after
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this point are considered to be part of the region until
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expand_eh_region_end () is invoked. */
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extern void expand_eh_region_start (void);
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/* Just like expand_eh_region_start, except if a cleanup action is
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entered on the cleanup chain, the TREE_PURPOSE of the element put
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on the chain is DECL. DECL should be the associated VAR_DECL, if
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any, otherwise it should be NULL_TREE. */
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extern void expand_eh_region_start_for_decl (tree);
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/* Start an exception handling region for the given cleanup action.
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All instructions emitted after this point are considered to be part
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of the region until expand_eh_region_end () is invoked. CLEANUP is
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the cleanup action to perform. The return value is true if the
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exception region was optimized away. If that case,
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expand_eh_region_end does not need to be called for this cleanup,
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nor should it be.
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This routine notices one particular common case in C++ code
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generation, and optimizes it so as to not need the exception
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region. */
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extern int expand_eh_region_start_tree (tree, tree);
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/* End an exception handling region. The information about the region
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is found on the top of ehstack.
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HANDLER is either the cleanup for the exception region, or if we're
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marking the end of a try block, HANDLER is integer_zero_node.
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HANDLER will be transformed to rtl when expand_leftover_cleanups ()
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is invoked. */
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extern void expand_eh_region_end (tree);
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/* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL
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should be set; the other must be NULL. */
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extern void push_label_entry (struct label_node **labelstack, rtx rlabel, tree tlabel);
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/* Pop the topmost entry from LABELSTACK and return its value as an
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rtx node. If LABELSTACK is empty, return NULL. */
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extern rtx pop_label_entry (struct label_node **labelstack);
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/* Return the topmost entry of LABELSTACK as a tree node, or return
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NULL_TREE if LABELSTACK is empty. */
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extern tree top_label_entry (struct label_node **labelstack);
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/* A set of insns for the catch clauses in the current function. They
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will be emitted at the end of the current function. */
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extern rtx catch_clauses;
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#endif
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/* Test: is exception handling turned on? */
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extern int doing_eh (int);
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/* Toplevel initialization for EH. */
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void set_exception_lang_code (int);
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void set_exception_version_code (int);
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/* A list of handlers asocciated with an exception region. HANDLER_LABEL
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is the the label that control should be transfered to if the data
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in TYPE_INFO matches an exception. a value of NULL_TREE for TYPE_INFO
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means This is a cleanup, and must always be called. A value of
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CATCH_ALL_TYPE works like a cleanup, but a call to the runtime matcher
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is still performed to avoid being caught by a different language
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exception. NEXT is a pointer to the next handler for this region.
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NULL means there are no more. */
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typedef struct handler_info
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{
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rtx handler_label;
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int handler_number;
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void *type_info;
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struct handler_info *next;
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} handler_info;
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/* Add new handler information to an exception range. The first parameter
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specifies the range number (returned from new_eh_entry()). The second
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parameter specifies the handler. By default the handler is inserted at
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the end of the list. A handler list may contain only ONE NULL_TREE
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typeinfo entry. Regardless where it is positioned, a NULL_TREE entry
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is always output as the LAST handler in the exception table for a region. */
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void add_new_handler (int, struct handler_info *);
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/* Remove a handler label. The handler label is being deleted, so all
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regions which reference this handler should have it removed from their
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list of possible handlers. Any region which has the final handler
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removed can be deleted. */
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void remove_handler (rtx);
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/* Create a new handler structure initialized with the handler label and
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typeinfo fields passed in. */
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struct handler_info *get_new_handler (rtx, void *);
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/* Make a duplicate of an exception region by copying all the handlers
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for an exception region. Return the new handler index. */
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int duplicate_eh_handlers (int, int, rtx (*)(rtx));
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/* map symbol refs for rethrow */
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rtx rethrow_symbol_map (rtx, rtx (*)(rtx));
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/* Is the rethrow label for a region used? */
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int rethrow_used (int);
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/* Return the region number a this is the rethrow label for. */
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int eh_region_from_symbol (rtx);
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/* Get a pointer to the first handler in an exception region's list. */
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struct handler_info *get_first_handler (int);
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/* Find all the runtime handlers type matches currently referenced */
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int find_all_handler_type_matches (void ***);
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extern void init_eh (void);
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/* Initialization for the per-function EH data. */
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extern void init_eh_for_function (void);
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/* Generate an exception label. Use instead of gen_label_rtx */
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extern rtx gen_exception_label (void);
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/* Adds an EH table entry for EH entry number N. Called from
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final_scan_insn for NOTE_INSN_EH_REGION_BEG. */
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extern void add_eh_table_entry (int n);
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/* Start a catch clause, triggered by runtime value paramter. */
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#ifdef TREE_CODE
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extern void start_catch_handler (tree);
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#endif
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/* End an individual catch clause. */
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extern void end_catch_handler (void);
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/* Returns a non-zero value if we need to output an exception table. */
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extern int exception_table_p (void);
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/* Outputs the exception table if we have one. */
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extern void output_exception_table (void);
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/* Given a return address in ADDR, determine the address we should use
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to find the corresponding EH region. */
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extern rtx eh_outer_context (rtx addr);
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/* Called at the start of a block of try statements for which there is
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a supplied catch handler. */
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extern void expand_start_try_stmts (void);
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/* Called at the start of a block of catch statements. It terminates the
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previous set of try statements. */
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extern void expand_start_all_catch (void);
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/* Called at the end of a block of catch statements. */
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extern void expand_end_all_catch (void);
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#ifdef TREE_CODE
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/* Create a new exception region and add the handler for the region
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onto a list. These regions will be ended (and their handlers
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emitted) when end_protect_partials is invoked. */
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extern void add_partial_entry (tree handler);
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#endif
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/* End all of the pending exception regions that have handlers added with
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push_protect_entry (). */
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extern void end_protect_partials (void);
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/* An internal throw. */
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extern void expand_internal_throw (void);
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/* Called from expand_exception_blocks and expand_end_catch_block to
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expand and pending handlers. */
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extern void expand_leftover_cleanups (void);
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/* If necessary, emit insns to get EH context for the current
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function. */
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extern void emit_eh_context (void);
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/* Builds a list of handler labels and puts them in the global
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variable exception_handler_labels. */
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extern void find_exception_handler_labels (void);
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/* Determine if an arbitrary label is an exception label */
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extern int is_exception_handler_label (int);
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/* Performs sanity checking on the check_exception_handler_labels
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list. */
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extern void check_exception_handler_labels (void);
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/* A stack used to keep track of the label used to resume normal program
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flow out of the current exception handler region. */
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extern struct label_node *caught_return_label_stack;
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/* Keeps track of the label used as the context of a throw to rethrow an
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exception to the outer exception region. */
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extern struct label_node *outer_context_label_stack;
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/* A random area used for purposes elsewhere. */
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extern struct label_node *false_label_stack;
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/* A list of labels used for exception handlers. It is created by
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find_exception_handler_labels for the optimization passes. */
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extern rtx exception_handler_labels;
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/* Performs optimizations for exception handling, such as removing
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unnecessary exception regions. Invoked from jump_optimize (). */
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extern void exception_optimize (void);
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/* Return EH context (and set it up once per fn). */
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extern rtx get_eh_context (void);
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/* Get the dynamic handler chain. */
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extern rtx get_dynamic_handler_chain (void);
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/* Get the dynamic cleanup chain. */
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extern rtx get_dynamic_cleanup_chain (void);
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/* Throw an exception. */
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extern void emit_throw (void);
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/* One to use setjmp/longjmp method of generating code. */
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extern int exceptions_via_longjmp;
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/* One to enable asynchronous exception support. */
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extern int asynchronous_exceptions;
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/* One to protect cleanup actions with a handler that calls
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__terminate, zero otherwise. */
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extern int protect_cleanup_actions_with_terminate;
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#ifdef TREE_CODE
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extern tree protect_with_terminate (tree);
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#endif
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extern void expand_fixup_region_start (void);
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#ifdef TREE_CODE
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extern void expand_fixup_region_end (tree);
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#endif
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/* Various hooks for the DWARF 2 __throw routine. */
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void expand_builtin_unwind_init (void);
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#ifdef TREE_CODE
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rtx expand_builtin_frob_return_addr (tree);
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rtx expand_builtin_extract_return_addr (tree);
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void expand_builtin_eh_return (tree, tree, tree);
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#endif
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void expand_eh_return (void);
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/* Checking whether 2 instructions are within the same exception region. */
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int in_same_eh_region (rtx, rtx);
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void free_insn_eh_region (void);
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void init_insn_eh_region (rtx, int);
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#ifdef rtx
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#undef rtx
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#endif
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