1/* Exception Handling interface routines. 2 Copyright (C) 1996, 1997, 1998 Free Software Foundation, Inc. 3 Contributed by Mike Stump <mrs@cygnus.com>. 4 5This file is part of GNU CC. 6 7GNU CC is free software; you can redistribute it and/or modify 8it under the terms of the GNU General Public License as published by 9the Free Software Foundation; either version 2, or (at your option) 10any later version. 11 12GNU CC is distributed in the hope that it will be useful, 13but WITHOUT ANY WARRANTY; without even the implied warranty of 14MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15GNU General Public License for more details. 16 17You should have received a copy of the GNU General Public License 18along with GNU CC; see the file COPYING. If not, write to 19the Free Software Foundation, 59 Temple Place - Suite 330, 20Boston, MA 02111-1307, USA. */ 21 22#if !defined(NULL_RTX) && !defined(rtx) 23typedef struct rtx_def *_except_rtx; 24#define rtx _except_rtx 25#endif 26 27/* The label generated by expand_builtin_eh_return. */ 28 29extern rtx eh_return_stub_label; 30 31#ifdef TREE_CODE 32 33/* A stack of labels. CHAIN points to the next entry in the stack. */ 34 35struct label_node { 36 union { 37 rtx rlabel; 38 tree tlabel; 39 } u; 40 struct label_node *chain; 41}; 42 43/* An eh_entry is used to describe one exception handling region. 44 45 OUTER_CONTEXT is the label used for rethrowing into the outer context. 46 47 EXCEPTION_HANDLER_LABEL is the label corresponding to the handler 48 for this region. 49 50 LABEL_USED indicates whether a CATCH block has already used this 51 label or not. New ones are needed for additional catch blocks if 52 it has. 53 54 FALSE_LABEL is used when either setjmp/longjmp exceptions are in 55 use, or old style table exceptions. It contains the label for 56 branching to the next runtime type check as handlers are processed. 57 58 FINALIZATION is the tree codes for the handler, or is NULL_TREE if 59 one hasn't been generated yet, or is integer_zero_node to mark the 60 end of a group of try blocks. */ 61 62struct eh_entry { 63 rtx outer_context; 64 rtx exception_handler_label; 65 tree finalization; 66 int label_used; 67 rtx false_label; 68 rtx rethrow_label; 69}; 70 71/* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next 72 entry in the list, or is NULL if this is the last entry. */ 73 74struct eh_node { 75 struct eh_entry *entry; 76 struct eh_node *chain; 77}; 78 79/* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is 80 NULL if the stack is empty. */ 81 82struct eh_stack { 83 struct eh_node *top; 84}; 85 86/* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the 87 end (the latest entry). HEAD and TAIL are NULL if the queue is 88 empty. */ 89 90struct eh_queue { 91 struct eh_node *head; 92 struct eh_node *tail; 93}; 94 95/* Start an exception handling region. All instructions emitted after 96 this point are considered to be part of the region until 97 expand_eh_region_end () is invoked. */ 98 99extern void expand_eh_region_start PROTO((void)); 100 101/* Just like expand_eh_region_start, except if a cleanup action is 102 entered on the cleanup chain, the TREE_PURPOSE of the element put 103 on the chain is DECL. DECL should be the associated VAR_DECL, if 104 any, otherwise it should be NULL_TREE. */ 105 106extern void expand_eh_region_start_for_decl PROTO((tree)); 107 108/* Start an exception handling region for the given cleanup action. 109 All instructions emitted after this point are considered to be part 110 of the region until expand_eh_region_end () is invoked. CLEANUP is 111 the cleanup action to perform. The return value is true if the 112 exception region was optimized away. If that case, 113 expand_eh_region_end does not need to be called for this cleanup, 114 nor should it be. 115 116 This routine notices one particular common case in C++ code 117 generation, and optimizes it so as to not need the exception 118 region. */ 119 120extern int expand_eh_region_start_tree PROTO((tree, tree)); 121 122/* End an exception handling region. The information about the region 123 is found on the top of ehstack. 124 125 HANDLER is either the cleanup for the exception region, or if we're 126 marking the end of a try block, HANDLER is integer_zero_node. 127 128 HANDLER will be transformed to rtl when expand_leftover_cleanups () 129 is invoked. */ 130 131extern void expand_eh_region_end PROTO((tree)); 132 133/* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL 134 should be set; the other must be NULL. */ 135 136extern void push_label_entry PROTO((struct label_node **labelstack, rtx rlabel, tree tlabel)); 137 138/* Pop the topmost entry from LABELSTACK and return its value as an 139 rtx node. If LABELSTACK is empty, return NULL. */ 140 141extern rtx pop_label_entry PROTO((struct label_node **labelstack)); 142 143/* Return the topmost entry of LABELSTACK as a tree node, or return 144 NULL_TREE if LABELSTACK is empty. */ 145 146extern tree top_label_entry PROTO((struct label_node **labelstack)); 147 148/* A set of insns for the catch clauses in the current function. They 149 will be emitted at the end of the current function. */ 150 151extern rtx catch_clauses; 152 153#endif 154 155/* Test: is exception handling turned on? */ 156 157extern int doing_eh PROTO ((int)); 158 159/* Toplevel initialization for EH. */ 160 161void set_exception_lang_code PROTO((int)); 162void set_exception_version_code PROTO((int)); 163 164/* A list of handlers asocciated with an exception region. HANDLER_LABEL 165 is the the label that control should be transfered to if the data 166 in TYPE_INFO matches an exception. a value of NULL_TREE for TYPE_INFO 167 means This is a cleanup, and must always be called. A value of 168 CATCH_ALL_TYPE works like a cleanup, but a call to the runtime matcher 169 is still performed to avoid being caught by a different language 170 exception. NEXT is a pointer to the next handler for this region. 171 NULL means there are no more. */ 172 173typedef struct handler_info 174{ 175 rtx handler_label; 176 int handler_number; 177 void *type_info; 178 struct handler_info *next; 179} handler_info; 180 181 182/* Add new handler information to an exception range. The first parameter 183 specifies the range number (returned from new_eh_entry()). The second 184 parameter specifies the handler. By default the handler is inserted at 185 the end of the list. A handler list may contain only ONE NULL_TREE 186 typeinfo entry. Regardless where it is positioned, a NULL_TREE entry 187 is always output as the LAST handler in the exception table for a region. */ 188 189void add_new_handler PROTO((int, struct handler_info *)); 190 191/* Remove a handler label. The handler label is being deleted, so all 192 regions which reference this handler should have it removed from their 193 list of possible handlers. Any region which has the final handler 194 removed can be deleted. */ 195 196void remove_handler PROTO((rtx)); 197 198/* Create a new handler structure initialized with the handler label and 199 typeinfo fields passed in. */ 200 201struct handler_info *get_new_handler PROTO((rtx, void *)); 202 203/* Make a duplicate of an exception region by copying all the handlers 204 for an exception region. Return the new handler index. */ 205 206int duplicate_eh_handlers PROTO((int, int, rtx (*)(rtx))); 207 208/* map symbol refs for rethrow */ 209 210rtx rethrow_symbol_map PROTO((rtx, rtx (*)(rtx))); 211 212/* Is the rethrow label for a region used? */ 213 214int rethrow_used PROTO((int)); 215 216/* Return the region number a this is the rethrow label for. */ 217 218int eh_region_from_symbol PROTO((rtx)); 219 220/* Get a pointer to the first handler in an exception region's list. */ 221 222struct handler_info *get_first_handler PROTO((int)); 223 224/* Find all the runtime handlers type matches currently referenced */ 225 226int find_all_handler_type_matches PROTO((void ***)); 227 228extern void init_eh PROTO((void)); 229 230/* Initialization for the per-function EH data. */ 231 232extern void init_eh_for_function PROTO((void)); 233 234/* Generate an exception label. Use instead of gen_label_rtx */ 235 236extern rtx gen_exception_label PROTO((void)); 237 238/* Adds an EH table entry for EH entry number N. Called from 239 final_scan_insn for NOTE_INSN_EH_REGION_BEG. */ 240 241extern void add_eh_table_entry PROTO((int n)); 242 243/* Start a catch clause, triggered by runtime value paramter. */ 244 245#ifdef TREE_CODE 246extern void start_catch_handler PROTO((tree)); 247#endif 248 249/* End an individual catch clause. */ 250 251extern void end_catch_handler PROTO((void)); 252 253/* Returns a non-zero value if we need to output an exception table. */ 254 255extern int exception_table_p PROTO((void)); 256 257/* Outputs the exception table if we have one. */ 258 259extern void output_exception_table PROTO((void)); 260 261/* Given a return address in ADDR, determine the address we should use 262 to find the corresponding EH region. */ 263 264extern rtx eh_outer_context PROTO((rtx addr)); 265 266/* Called at the start of a block of try statements for which there is 267 a supplied catch handler. */ 268 269extern void expand_start_try_stmts PROTO((void)); 270 271/* Called at the start of a block of catch statements. It terminates the 272 previous set of try statements. */ 273 274extern void expand_start_all_catch PROTO((void)); 275 276/* Called at the end of a block of catch statements. */ 277 278extern void expand_end_all_catch PROTO((void)); 279 280#ifdef TREE_CODE 281/* Create a new exception region and add the handler for the region 282 onto a list. These regions will be ended (and their handlers 283 emitted) when end_protect_partials is invoked. */ 284 285extern void add_partial_entry PROTO((tree handler)); 286#endif 287 288/* End all of the pending exception regions that have handlers added with 289 push_protect_entry (). */ 290 291extern void end_protect_partials PROTO((void)); 292 293/* An internal throw. */ 294 295extern void expand_internal_throw PROTO((void)); 296 297/* Called from expand_exception_blocks and expand_end_catch_block to 298 expand and pending handlers. */ 299 300extern void expand_leftover_cleanups PROTO((void)); 301 302/* If necessary, emit insns to get EH context for the current 303 function. */ 304 305extern void emit_eh_context PROTO((void)); 306 307/* Builds a list of handler labels and puts them in the global 308 variable exception_handler_labels. */ 309 310extern void find_exception_handler_labels PROTO((void)); 311 312/* Determine if an arbitrary label is an exception label */ 313 314extern int is_exception_handler_label PROTO((int)); 315 316/* Performs sanity checking on the check_exception_handler_labels 317 list. */ 318 319extern void check_exception_handler_labels PROTO((void)); 320 321/* A stack used to keep track of the label used to resume normal program 322 flow out of the current exception handler region. */ 323 324extern struct label_node *caught_return_label_stack; 325 326/* Keeps track of the label used as the context of a throw to rethrow an 327 exception to the outer exception region. */ 328 329extern struct label_node *outer_context_label_stack; 330 331/* A random area used for purposes elsewhere. */ 332 333extern struct label_node *false_label_stack; 334 335/* A list of labels used for exception handlers. It is created by 336 find_exception_handler_labels for the optimization passes. */ 337 338extern rtx exception_handler_labels; 339 340/* Performs optimizations for exception handling, such as removing 341 unnecessary exception regions. Invoked from jump_optimize (). */ 342 343extern void exception_optimize PROTO((void)); 344 345/* Return EH context (and set it up once per fn). */ 346extern rtx get_eh_context PROTO((void)); 347 348/* Get the dynamic handler chain. */ 349extern rtx get_dynamic_handler_chain PROTO((void)); 350 351/* Get the dynamic cleanup chain. */ 352extern rtx get_dynamic_cleanup_chain PROTO((void)); 353 354/* Throw an exception. */ 355 356extern void emit_throw PROTO((void)); 357 358/* One to use setjmp/longjmp method of generating code. */ 359 360extern int exceptions_via_longjmp; 361 362/* One to enable asynchronous exception support. */ 363 364extern int asynchronous_exceptions; 365 366/* One to protect cleanup actions with a handler that calls 367 __terminate, zero otherwise. */ 368 369extern int protect_cleanup_actions_with_terminate; 370 371#ifdef TREE_CODE 372extern tree protect_with_terminate PROTO((tree)); 373#endif 374 375extern void expand_fixup_region_start PROTO((void)); 376#ifdef TREE_CODE 377extern void expand_fixup_region_end PROTO((tree)); 378#endif 379 380/* Various hooks for the DWARF 2 __throw routine. */ 381 382void expand_builtin_unwind_init PROTO((void)); 383rtx expand_builtin_dwarf_fp_regnum PROTO((void)); 384#ifdef TREE_CODE 385rtx expand_builtin_frob_return_addr PROTO((tree)); 386rtx expand_builtin_extract_return_addr PROTO((tree)); 387rtx expand_builtin_dwarf_reg_size PROTO((tree, rtx)); 388void expand_builtin_eh_return PROTO((tree, tree, tree)); 389#endif 390void expand_eh_return PROTO((void)); 391 392 393/* Checking whether 2 instructions are within the same exception region. */ 394 395int in_same_eh_region PROTO((rtx, rtx)); 396void free_insn_eh_region PROTO((void)); 397void init_insn_eh_region PROTO((rtx, int)); 398 399#ifdef rtx 400#undef rtx 401#endif 402