1 /* Exception Handling interface routines.
2 Copyright (C) 1996 Free Software Foundation, Inc.
3 Contributed by Mike Stump <mrs@cygnus.com>.
5 This file is part of GNU CC.
7 GNU CC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2, or (at your option)
12 GNU CC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with GNU CC; see the file COPYING. If not, write to
19 the Free Software Foundation, 59 Temple Place - Suite 330,
20 Boston, MA 02111-1307, USA. */
29 /* A stack of labels. CHAIN points to the next entry in the stack. */
36 struct label_node
*chain
;
39 /* An eh_entry is used to describe one exception handling region.
41 START_LABEL is the label corresponding to the start of the region.
43 END_LABEL is the label corresponding to the end of the region.
45 EXCEPTION_HANDLER_LABEL is the label corresponding to the handler
48 FINALIZATION is the tree codes for the handler, or is NULL_TREE if
49 one hasn't been generated yet, or is integer_zero_node to mark the
50 end of a group of try blocks. */
55 rtx exception_handler_label
;
60 /* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next
61 entry in the list, or is NULL if this is the last entry. */
64 struct eh_entry
*entry
;
65 struct eh_node
*chain
;
68 /* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is
69 NULL if the stack is empty. */
75 /* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the
76 end (the latest entry). HEAD and TAIL are NULL if the queue is
85 extern void expand_eh_region_start
PROTO((void));
87 extern void expand_eh_region_end
PROTO((tree
));
89 /* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL
90 should be set; the other must be NULL. */
92 extern void push_label_entry
PROTO((struct label_node
**labelstack
, rtx rlabel
, tree tlabel
));
94 /* Pop the topmost entry from LABELSTACK and return its value as an
95 rtx node. If LABELSTACK is empty, return NULL. */
97 extern rtx pop_label_entry
PROTO((struct label_node
**labelstack
));
99 /* Return the topmost entry of LABELSTACK as a tree node, or return
100 NULL_TREE if LABELSTACK is empty. */
102 extern tree top_label_entry
PROTO((struct label_node
**labelstack
));
104 /* The stack used to keep track of the exception region corresponding to
105 the current instruction. */
107 extern struct eh_stack ehstack
;
109 /* A queue used to track closed exception regions whose handlers have
110 not been emitted yet. */
112 extern struct eh_queue ehqueue
;
114 /* A set of insns for the catch clauses in the current function. They
115 will be emitted at the end of the current function. */
117 extern rtx catch_clauses
;
123 /* Toplevel initialization for EH. */
125 extern void init_eh
PROTO((void));
127 /* Initialization for the per-function EH data. */
129 extern void init_eh_for_function
PROTO((void));
131 /* Saves the current per-function EH data into P. */
133 extern void save_eh_status
PROTO((struct function
*p
));
135 /* Restores the per-function EH data from P. */
137 extern void restore_eh_status
PROTO((struct function
*p
));
139 /* Adds an EH table entry for EH entry number N. Called from
140 final_scan_insn for NOTE_INSN_EH_REGION_BEG. */
142 extern void add_eh_table_entry
PROTO((int n
));
144 /* Returns a non-zero value if we need to output an exception table. */
146 extern int exception_table_p
PROTO((void));
148 /* Outputs the exception table if we have one. */
150 extern void output_exception_table
PROTO((void));
152 /* Given a return address in ADDR, determine the address we should use
153 to find the corresponding EH region. */
155 extern rtx eh_outer_context
PROTO((rtx addr
));
157 /* Called at the start of a block of try statements for which there is
158 a supplied catch handler. */
160 extern void expand_start_try_stmts
PROTO((void));
162 /* Called at the start of a block of catch statements. It terminates the
163 previous set of try statements. */
165 extern void expand_start_all_catch
PROTO((void));
167 /* Called at the end of a block of catch statements. */
169 extern void expand_end_all_catch
PROTO((void));
172 /* Create a new exception region and add the handler for the region
173 onto a list. These regions will be ended (and their handlers
174 emitted) when end_protect_partials is invoked. */
176 extern void add_partial_entry
PROTO((tree handler
));
179 /* End all of the pending exception regions that have handlers added with
180 push_protect_entry (). */
182 extern void end_protect_partials
PROTO((void));
184 /* An internal throw with a direct CONTEXT we want to throw
185 from. CONTEXT must be a label. */
187 extern void expand_internal_throw
PROTO((rtx context
));
189 /* Called from expand_exception_blocks and expand_end_catch_block to
190 expand and pending handlers. */
192 extern void expand_leftover_cleanups
PROTO((void));
194 /* If necessary, emit insns for the start of per-function unwinder for
195 the current function. */
197 extern void emit_unwinder
PROTO((void));
199 /* If necessary, emit insns for the end of the per-function unwinder
200 for the current function. */
202 extern void end_eh_unwinder
PROTO((void));
204 /* Builds a list of handler labels and puts them in the global
205 variable exception_handler_labels. */
207 extern void find_exception_handler_labels
PROTO((void));
209 /* Performs sanity checking on the check_exception_handler_labels
212 extern void check_exception_handler_labels
PROTO((void));
214 /* A stack used to keep track of the label used to resume normal program
215 flow out of the current exception handler region. */
217 extern struct label_node
*caught_return_label_stack
;
219 /* A random area used for purposes elsewhere. */
221 extern struct label_node
*false_label_stack
;
223 /* A list of labels used for exception handlers. It is created by
224 find_exception_handler_labels for the optimization passes. */
226 extern rtx exception_handler_labels
;
228 /* The rtx for the saved PC value. */
230 extern rtx eh_saved_pc_rtx
;
232 /* Performs optimizations for exception handling, such as removing
233 unnecessary exception regions. Invoked from jump_optimize (). */
235 extern void exception_optimize
PROTO((void));