1 /* Handle exceptions for GNU compiler for the Java(TM) language.
2 Copyright (C) 1997-2014 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>.
20 Java and all Java-based marks are trademarks or registered trademarks
21 of Sun Microsystems, Inc. in the United States and other countries.
22 The Free Software Foundation is independent of Sun Microsystems, Inc. */
26 #include "coretypes.h"
29 #include "stringpool.h"
30 #include "stor-layout.h"
31 #include "java-tree.h"
33 #include "java-opcodes.h"
35 #include "java-except.h"
36 #include "diagnostic-core.h"
38 #include "tree-iterator.h"
41 static void expand_start_java_handler (struct eh_range
*);
42 static struct eh_range
*find_handler_in_range (int, struct eh_range
*,
44 static void check_start_handlers (struct eh_range
*, int);
45 static void free_eh_ranges (struct eh_range
*range
);
47 struct eh_range
*current_method_handlers
;
49 struct eh_range
*current_try_block
= NULL
;
51 /* These variables are used to speed up find_handler. */
53 static int cache_range_start
, cache_range_end
;
54 static struct eh_range
*cache_range
;
55 static struct eh_range
*cache_next_child
;
57 /* A dummy range that represents the entire method. */
59 struct eh_range whole_range
;
61 /* Check the invariants of the structure we're using to contain
62 exception regions. Either returns true or fails an assertion
66 sanity_check_exception_range (struct eh_range
*range
)
68 struct eh_range
*ptr
= range
->first_child
;
69 for (; ptr
; ptr
= ptr
->next_sibling
)
71 gcc_assert (ptr
->outer
== range
72 && ptr
->end_pc
> ptr
->start_pc
);
73 if (ptr
->next_sibling
)
74 gcc_assert (ptr
->next_sibling
->start_pc
>= ptr
->end_pc
);
75 gcc_assert (ptr
->start_pc
>= ptr
->outer
->start_pc
76 && ptr
->end_pc
<= ptr
->outer
->end_pc
);
77 (void) sanity_check_exception_range (ptr
);
82 #if defined(DEBUG_JAVA_BINDING_LEVELS)
83 extern int is_class_level
;
84 extern int current_pc
;
85 extern int binding_depth
;
86 extern void indent (void);
88 print_ranges (struct eh_range
*range
)
93 struct eh_range
*child
= range
->first_child
;
96 fprintf (stderr
, "handler pc %d --> %d ", range
->start_pc
, range
->end_pc
);
98 tree handler
= range
->handlers
;
99 for ( ; handler
!= NULL_TREE
; handler
= TREE_CHAIN (handler
))
101 tree type
= TREE_PURPOSE (handler
);
103 type
= throwable_type_node
;
104 fprintf (stderr
, " type=%s ", IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type
))));
106 fprintf (stderr
, "\n");
108 int saved
= binding_depth
;
110 print_ranges (child
);
111 binding_depth
= saved
;
113 print_ranges (range
->next_sibling
);
117 /* Search for the most specific eh_range containing PC.
118 Assume PC is within RANGE.
119 CHILD is a list of children of RANGE such that any
120 previous children have end_pc values that are too low. */
122 static struct eh_range
*
123 find_handler_in_range (int pc
, struct eh_range
*range
, struct eh_range
*child
)
125 for (; child
!= NULL
; child
= child
->next_sibling
)
127 if (pc
< child
->start_pc
)
129 if (pc
< child
->end_pc
)
130 return find_handler_in_range (pc
, child
, child
->first_child
);
133 cache_range_start
= pc
;
134 cache_next_child
= child
;
135 cache_range_end
= child
== NULL
? range
->end_pc
: child
->start_pc
;
139 /* Find the inner-most handler that contains PC. */
142 find_handler (int pc
)
145 if (pc
>= cache_range_start
)
148 if (pc
< cache_range_end
)
150 while (pc
>= h
->end_pc
)
152 cache_next_child
= h
->next_sibling
;
159 cache_next_child
= h
->first_child
;
161 return find_handler_in_range (pc
, h
, cache_next_child
);
165 free_eh_ranges (struct eh_range
*range
)
169 struct eh_range
*next
= range
->next_sibling
;
170 free_eh_ranges (range
->first_child
);
171 if (range
!= &whole_range
)
177 /* Called to re-initialize the exception machinery for a new method. */
180 method_init_exceptions (void)
182 free_eh_ranges (&whole_range
);
183 whole_range
.start_pc
= 0;
184 whole_range
.end_pc
= DECL_CODE_LENGTH (current_function_decl
) + 1;
185 whole_range
.outer
= NULL
;
186 whole_range
.first_child
= NULL
;
187 whole_range
.next_sibling
= NULL
;
188 cache_range_start
= 0xFFFFFF;
191 /* Split an exception range into two at PC. The sub-ranges that
192 belong to the range are split and distributed between the two new
196 split_range (struct eh_range
*range
, int pc
)
198 struct eh_range
*ptr
;
199 struct eh_range
**first_child
, **second_child
;
202 /* First, split all the sub-ranges. */
203 for (ptr
= range
->first_child
; ptr
; ptr
= ptr
->next_sibling
)
205 if (pc
> ptr
->start_pc
208 split_range (ptr
, pc
);
212 /* Create a new range. */
213 h
= XNEW (struct eh_range
);
216 h
->end_pc
= range
->end_pc
;
217 h
->next_sibling
= range
->next_sibling
;
218 range
->next_sibling
= h
;
220 h
->handlers
= build_tree_list (TREE_PURPOSE (range
->handlers
),
221 TREE_VALUE (range
->handlers
));
222 h
->next_sibling
= NULL
;
225 h
->outer
= range
->outer
;
226 h
->first_child
= NULL
;
228 ptr
= range
->first_child
;
229 first_child
= &range
->first_child
;
230 second_child
= &h
->first_child
;
232 /* Distribute the sub-ranges between the two new ranges. */
233 for (ptr
= range
->first_child
; ptr
; ptr
= ptr
->next_sibling
)
235 if (ptr
->start_pc
< pc
)
239 first_child
= &ptr
->next_sibling
;
245 second_child
= &ptr
->next_sibling
;
249 *second_child
= NULL
;
253 /* Add an exception range.
255 There are some missed optimization opportunities here. For
256 example, some bytecode obfuscators generate seemingly
257 nonoverlapping exception ranges which, when coalesced, do in fact
258 nest correctly. We could merge these, but we'd have to fix up all
259 the enclosed regions first and perhaps create a new range anyway if
260 it overlapped existing ranges.
262 Also, we don't attempt to detect the case where two previously
263 added disjoint ranges could be coalesced by a new range. */
266 add_handler (int start_pc
, int end_pc
, tree handler
, tree type
)
268 struct eh_range
*ptr
, *h
;
269 struct eh_range
**first_child
, **prev
;
271 /* First, split all the existing ranges that we need to enclose. */
272 for (ptr
= whole_range
.first_child
; ptr
; ptr
= ptr
->next_sibling
)
274 if (start_pc
> ptr
->start_pc
275 && start_pc
< ptr
->end_pc
)
277 split_range (ptr
, start_pc
);
280 if (end_pc
> ptr
->start_pc
281 && end_pc
< ptr
->end_pc
)
283 split_range (ptr
, end_pc
);
286 if (ptr
->start_pc
>= end_pc
)
290 /* Create the new range. */
291 h
= XNEW (struct eh_range
);
292 first_child
= &h
->first_child
;
294 h
->start_pc
= start_pc
;
296 h
->first_child
= NULL
;
297 h
->outer
= NULL_EH_RANGE
;
298 h
->handlers
= build_tree_list (type
, handler
);
299 h
->next_sibling
= NULL
;
303 /* Find every range at the top level that will be a sub-range of the
304 range we're inserting and make it so. */
306 struct eh_range
**prev
= &whole_range
.first_child
;
307 for (ptr
= *prev
; ptr
;)
309 struct eh_range
*next
= ptr
->next_sibling
;
311 if (ptr
->start_pc
>= end_pc
)
314 if (ptr
->start_pc
< start_pc
)
316 prev
= &ptr
->next_sibling
;
318 else if (ptr
->start_pc
>= start_pc
319 && ptr
->start_pc
< end_pc
)
323 first_child
= &ptr
->next_sibling
;
325 ptr
->next_sibling
= NULL
;
332 /* Find the right place to insert the new range. */
333 prev
= &whole_range
.first_child
;
334 for (ptr
= *prev
; ptr
; prev
= &ptr
->next_sibling
, ptr
= ptr
->next_sibling
)
336 gcc_assert (ptr
->outer
== NULL_EH_RANGE
);
337 if (ptr
->start_pc
>= start_pc
)
341 /* And insert it there. */
345 h
->next_sibling
= ptr
;
346 h
->outer
= ptr
->outer
;
351 /* if there are any handlers for this range, issue start of region */
353 expand_start_java_handler (struct eh_range
*range
)
355 #if defined(DEBUG_JAVA_BINDING_LEVELS)
357 fprintf (stderr
, "expand start handler pc %d --> %d\n",
358 current_pc
, range
->end_pc
);
359 #endif /* defined(DEBUG_JAVA_BINDING_LEVELS) */
361 register_exception_range (range
, range
->start_pc
, range
->end_pc
);
366 prepare_eh_table_type (tree type
)
375 /* The "type" (match_info) in a (Java) exception table is a pointer to:
376 * a) NULL - meaning match any type in a try-finally.
377 * b) a pointer to a pointer to a class.
378 * c) a pointer to a pointer to a utf8_ref. The pointer is
379 * rewritten to point to the appropriate class. */
381 if (type
== NULL_TREE
)
384 if (TYPE_TO_RUNTIME_MAP (output_class
) == NULL
)
385 TYPE_TO_RUNTIME_MAP (output_class
) = java_treetreehash_create (10);
387 slot
= java_treetreehash_new (TYPE_TO_RUNTIME_MAP (output_class
), type
);
389 return TREE_VALUE (*slot
);
391 if (is_compiled_class (type
) && !flag_indirect_dispatch
)
393 name
= IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type
)));
394 buf
= (char *) alloca (strlen (name
) + 5);
395 sprintf (buf
, "%s_ref", name
);
396 decl
= build_decl (input_location
,
397 VAR_DECL
, get_identifier (buf
), ptr_type_node
);
398 TREE_STATIC (decl
) = 1;
399 DECL_ARTIFICIAL (decl
) = 1;
400 DECL_IGNORED_P (decl
) = 1;
401 TREE_READONLY (decl
) = 1;
402 TREE_THIS_VOLATILE (decl
) = 0;
403 DECL_INITIAL (decl
) = build_class_ref (type
);
404 layout_decl (decl
, 0);
406 exp
= build1 (ADDR_EXPR
, build_pointer_type (TREE_TYPE (decl
)), decl
);
410 utf8_ref
= build_utf8_ref (DECL_NAME (TYPE_NAME (type
)));
411 name
= IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (utf8_ref
, 0)));
412 buf
= (char *) alloca (strlen (name
) + 5);
413 sprintf (buf
, "%s_ref", name
);
414 decl
= build_decl (input_location
,
415 VAR_DECL
, get_identifier (buf
), utf8const_ptr_type
);
416 TREE_STATIC (decl
) = 1;
417 DECL_ARTIFICIAL (decl
) = 1;
418 DECL_IGNORED_P (decl
) = 1;
419 TREE_READONLY (decl
) = 1;
420 TREE_THIS_VOLATILE (decl
) = 0;
421 layout_decl (decl
, 0);
423 exp
= build1 (ADDR_EXPR
, build_pointer_type (utf8const_ptr_type
), decl
);
424 CONSTRUCTOR_APPEND_ELT (TYPE_CATCH_CLASSES (output_class
),
426 make_catch_class_record (exp
, utf8_ref
));
429 exp
= convert (ptr_type_node
, exp
);
431 *slot
= tree_cons (type
, exp
, NULL_TREE
);
437 expand_catch_class (void **entry
, void *x ATTRIBUTE_UNUSED
)
439 struct treetreehash_entry
*ite
= (struct treetreehash_entry
*) *entry
;
440 tree addr
= TREE_VALUE ((tree
)ite
->value
);
443 decl
= TREE_OPERAND (addr
, 0);
444 rest_of_decl_compilation (decl
, global_bindings_p (), 0);
448 /* For every class in the TYPE_TO_RUNTIME_MAP, expand the
449 corresponding object that is used by the runtime type matcher. */
452 java_expand_catch_classes (tree this_class
)
454 if (TYPE_TO_RUNTIME_MAP (this_class
))
456 (TYPE_TO_RUNTIME_MAP (this_class
),
457 expand_catch_class
, NULL
);
460 /* Build and push the variable that will hold the exception object
461 within this function. */
464 build_exception_object_var (void)
466 tree decl
= DECL_FUNCTION_EXC_OBJ (current_function_decl
);
469 decl
= build_decl (DECL_SOURCE_LOCATION (current_function_decl
),
470 VAR_DECL
, get_identifier ("#exc_obj"), ptr_type_node
);
471 DECL_IGNORED_P (decl
) = 1;
472 DECL_ARTIFICIAL (decl
) = 1;
474 DECL_FUNCTION_EXC_OBJ (current_function_decl
) = decl
;
475 pushdecl_function_level (decl
);
480 /* Build a reference to the jthrowable object being carried in the
484 build_exception_object_ref (tree type
)
488 /* Java only passes object via pointer and doesn't require adjusting.
489 The java object is immediately before the generic exception header. */
490 obj
= build_exception_object_var ();
491 obj
= fold_convert (build_pointer_type (type
), obj
);
492 obj
= fold_build_pointer_plus (obj
,
493 fold_build1 (NEGATE_EXPR
, sizetype
,
494 TYPE_SIZE_UNIT (TREE_TYPE (obj
))));
495 obj
= build1 (INDIRECT_REF
, type
, obj
);
500 /* If there are any handlers for this range, issue end of range,
501 and then all handler blocks */
503 expand_end_java_handler (struct eh_range
*range
)
505 tree handler
= range
->handlers
;
508 tree exc_obj
= build_exception_object_var ();
509 tree catches
= make_node (STATEMENT_LIST
);
510 tree_stmt_iterator catches_i
= tsi_last (catches
);
513 for (; handler
; handler
= TREE_CHAIN (handler
))
515 tree type
, eh_type
, x
;
516 tree stmts
= make_node (STATEMENT_LIST
);
517 tree_stmt_iterator stmts_i
= tsi_last (stmts
);
519 type
= TREE_PURPOSE (handler
);
521 type
= throwable_type_node
;
522 eh_type
= prepare_eh_table_type (type
);
524 x
= build_call_expr (builtin_decl_explicit (BUILT_IN_EH_POINTER
),
525 1, integer_zero_node
);
526 x
= build2 (MODIFY_EXPR
, void_type_node
, exc_obj
, x
);
527 tsi_link_after (&stmts_i
, x
, TSI_CONTINUE_LINKING
);
529 x
= build1 (GOTO_EXPR
, void_type_node
, TREE_VALUE (handler
));
530 tsi_link_after (&stmts_i
, x
, TSI_CONTINUE_LINKING
);
532 x
= build2 (CATCH_EXPR
, void_type_node
, eh_type
, stmts
);
533 tsi_link_after (&catches_i
, x
, TSI_CONTINUE_LINKING
);
535 /* Throwable can match anything in Java, and therefore
536 any subsequent handlers are unreachable. */
537 /* ??? If we're assured of no foreign language exceptions,
538 we'd be better off using NULL as the exception type
540 if (type
== throwable_type_node
)
545 *body
= build2 (TRY_CATCH_EXPR
, void_type_node
, *body
, catches
);
548 #if defined(DEBUG_JAVA_BINDING_LEVELS)
550 fprintf (stderr
, "expand end handler pc %d <-- %d\n",
551 current_pc
, range
->start_pc
);
552 #endif /* defined(DEBUG_JAVA_BINDING_LEVELS) */
555 /* Recursive helper routine for maybe_start_handlers. */
558 check_start_handlers (struct eh_range
*range
, int pc
)
560 if (range
!= NULL_EH_RANGE
&& range
->start_pc
== pc
)
562 check_start_handlers (range
->outer
, pc
);
563 if (!range
->expanded
)
564 expand_start_java_handler (range
);
569 /* Routine to see if exception handling is turned on.
570 DO_WARN is nonzero if we want to inform the user that exception
571 handling is turned off.
573 This is used to ensure that -fexceptions has been specified if the
574 compiler tries to use any exception-specific functions. */
579 if (! flag_exceptions
)
581 static int warned
= 0;
584 error ("exception handling disabled, use -fexceptions to enable");
592 static struct eh_range
*current_range
;
594 /* Emit any start-of-try-range starting at start_pc and ending after
598 maybe_start_try (int start_pc
, int end_pc
)
600 struct eh_range
*range
;
604 range
= find_handler (start_pc
);
605 while (range
!= NULL_EH_RANGE
&& range
->start_pc
== start_pc
606 && range
->end_pc
< end_pc
)
607 range
= range
->outer
;
609 current_range
= range
;
610 check_start_handlers (range
, start_pc
);