1 /* Handle exceptional things in C++.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
3 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008
4 Free Software Foundation, Inc.
5 Contributed by Michael Tiemann <tiemann@cygnus.com>
6 Rewritten by Mike Stump <mrs@cygnus.com>, based upon an
7 initial re-implementation courtesy Tad Hunt.
9 This file is part of GCC.
11 GCC is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 3, or (at your option)
16 GCC is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
21 You should have received a copy of the GNU General Public License
22 along with GCC; see the file COPYING3. If not see
23 <http://www.gnu.org/licenses/>. */
28 #include "coretypes.h"
39 #include "tree-inline.h"
40 #include "tree-iterator.h"
44 static void push_eh_cleanup (tree
);
45 static tree
prepare_eh_type (tree
);
46 static tree
build_eh_type_type (tree
);
47 static tree
do_begin_catch (void);
48 static int dtor_nothrow (tree
);
49 static tree
do_end_catch (tree
);
50 static bool decl_is_java_type (tree decl
, int err
);
51 static void initialize_handler_parm (tree
, tree
);
52 static tree
do_allocate_exception (tree
);
53 static tree
wrap_cleanups_r (tree
*, int *, void *);
54 static int complete_ptr_ref_or_void_ptr_p (tree
, tree
);
55 static bool is_admissible_throw_operand (tree
);
56 static int can_convert_eh (tree
, tree
);
57 static gimple
cp_protect_cleanup_actions (void);
59 /* Sets up all the global eh stuff that needs to be initialized at the
60 start of compilation. */
63 init_exception_processing (void)
67 /* void std::terminate (); */
68 push_namespace (std_identifier
);
69 tmp
= build_function_type (void_type_node
, void_list_node
);
70 terminate_node
= build_cp_library_fn_ptr ("terminate", tmp
);
71 TREE_THIS_VOLATILE (terminate_node
) = 1;
72 TREE_NOTHROW (terminate_node
) = 1;
75 /* void __cxa_call_unexpected(void *); */
76 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, void_list_node
);
77 tmp
= build_function_type (void_type_node
, tmp
);
79 = push_throw_library_fn (get_identifier ("__cxa_call_unexpected"), tmp
);
81 eh_personality_libfunc
= init_one_libfunc (USING_SJLJ_EXCEPTIONS
82 ? "__gxx_personality_sj0"
83 : "__gxx_personality_v0");
84 if (targetm
.arm_eabi_unwinder
)
85 unwind_resume_libfunc
= init_one_libfunc ("__cxa_end_cleanup");
87 default_init_unwind_resume_libfunc ();
89 lang_eh_runtime_type
= build_eh_type_type
;
90 lang_protect_cleanup_actions
= &cp_protect_cleanup_actions
;
93 /* Returns an expression to be executed if an unhandled exception is
94 propagated out of a cleanup region. */
97 cp_protect_cleanup_actions (void)
101 When the destruction of an object during stack unwinding exits
102 using an exception ... void terminate(); is called. */
103 return gimple_build_call (terminate_node
, 0);
107 prepare_eh_type (tree type
)
109 if (type
== NULL_TREE
)
111 if (type
== error_mark_node
)
112 return error_mark_node
;
114 /* peel back references, so they match. */
115 type
= non_reference (type
);
117 /* Peel off cv qualifiers. */
118 type
= TYPE_MAIN_VARIANT (type
);
120 /* Functions and arrays decay to pointers. */
121 type
= type_decays_to (type
);
126 /* Return the type info for TYPE as used by EH machinery. */
128 eh_type_info (tree type
)
132 if (type
== NULL_TREE
|| type
== error_mark_node
)
135 if (decl_is_java_type (type
, 0))
136 exp
= build_java_class_ref (TREE_TYPE (type
));
138 exp
= get_tinfo_decl (type
);
143 /* Build the address of a typeinfo decl for use in the runtime
144 matching field of the exception model. */
147 build_eh_type_type (tree type
)
149 tree exp
= eh_type_info (type
);
156 return convert (ptr_type_node
, build_address (exp
));
162 return build0 (EXC_PTR_EXPR
, ptr_type_node
);
165 /* Declare a function NAME, returning RETURN_TYPE, taking a single
166 parameter PARM_TYPE, with an empty exception specification.
168 Note that the C++ ABI document does not have a throw-specifier on
169 the routines declared below via this function. The declarations
170 are consistent with the actual implementations in libsupc++. */
173 declare_nothrow_library_fn (tree name
, tree return_type
, tree parm_type
)
175 tree tmp
= tree_cons (NULL_TREE
, parm_type
, void_list_node
);
176 return push_library_fn (name
, build_function_type (return_type
, tmp
),
180 /* Build up a call to __cxa_get_exception_ptr so that we can build a
181 copy constructor for the thrown object. */
184 do_get_exception_ptr (void)
188 fn
= get_identifier ("__cxa_get_exception_ptr");
189 if (!get_global_value_if_present (fn
, &fn
))
191 /* Declare void* __cxa_get_exception_ptr (void *) throw(). */
192 fn
= declare_nothrow_library_fn (fn
, ptr_type_node
, ptr_type_node
);
195 return cp_build_function_call (fn
, tree_cons (NULL_TREE
, build_exc_ptr (),
197 tf_warning_or_error
);
200 /* Build up a call to __cxa_begin_catch, to tell the runtime that the
201 exception has been handled. */
204 do_begin_catch (void)
208 fn
= get_identifier ("__cxa_begin_catch");
209 if (!get_global_value_if_present (fn
, &fn
))
211 /* Declare void* __cxa_begin_catch (void *) throw(). */
212 fn
= declare_nothrow_library_fn (fn
, ptr_type_node
, ptr_type_node
);
215 return cp_build_function_call (fn
, tree_cons (NULL_TREE
, build_exc_ptr (),
217 tf_warning_or_error
);
220 /* Returns nonzero if cleaning up an exception of type TYPE (which can be
221 NULL_TREE for a ... handler) will not throw an exception. */
224 dtor_nothrow (tree type
)
226 if (type
== NULL_TREE
)
229 if (!CLASS_TYPE_P (type
))
232 if (CLASSTYPE_LAZY_DESTRUCTOR (type
))
233 lazily_declare_fn (sfk_destructor
, type
);
235 return TREE_NOTHROW (CLASSTYPE_DESTRUCTORS (type
));
238 /* Build up a call to __cxa_end_catch, to destroy the exception object
239 for the current catch block if no others are currently using it. */
242 do_end_catch (tree type
)
246 fn
= get_identifier ("__cxa_end_catch");
247 if (!get_global_value_if_present (fn
, &fn
))
249 /* Declare void __cxa_end_catch (). */
250 fn
= push_void_library_fn (fn
, void_list_node
);
251 /* This can throw if the destructor for the exception throws. */
252 TREE_NOTHROW (fn
) = 0;
255 cleanup
= cp_build_function_call (fn
, NULL_TREE
, tf_warning_or_error
);
256 TREE_NOTHROW (cleanup
) = dtor_nothrow (type
);
261 /* This routine creates the cleanup for the current exception. */
264 push_eh_cleanup (tree type
)
266 finish_decl_cleanup (NULL_TREE
, do_end_catch (type
));
269 /* Return nonzero value if DECL is a Java type suitable for catch or
273 decl_is_java_type (tree decl
, int err
)
275 bool r
= (TREE_CODE (decl
) == POINTER_TYPE
276 && TREE_CODE (TREE_TYPE (decl
)) == RECORD_TYPE
277 && TYPE_FOR_JAVA (TREE_TYPE (decl
)));
281 if (TREE_CODE (decl
) == REFERENCE_TYPE
282 && TREE_CODE (TREE_TYPE (decl
)) == RECORD_TYPE
283 && TYPE_FOR_JAVA (TREE_TYPE (decl
)))
285 /* Can't throw a reference. */
286 error ("type %qT is disallowed in Java %<throw%> or %<catch%>",
293 = IDENTIFIER_GLOBAL_VALUE (get_identifier ("jthrowable"));
295 if (jthrow_node
== NULL_TREE
)
297 ("call to Java %<catch%> or %<throw%> with %<jthrowable%> undefined");
299 jthrow_node
= TREE_TYPE (TREE_TYPE (jthrow_node
));
301 if (! DERIVED_FROM_P (jthrow_node
, TREE_TYPE (decl
)))
303 /* Thrown object must be a Throwable. */
304 error ("type %qT is not derived from %<java::lang::Throwable%>",
313 /* Select the personality routine to be used for exception handling,
314 or issue an error if we need two different ones in the same
316 ??? At present eh_personality_libfunc is set to
317 __gxx_personality_(sj|v)0 in init_exception_processing - should it
318 be done here instead? */
320 choose_personality_routine (enum languages lang
)
335 if (lang
!= lang_cplusplus
)
340 if (lang
!= lang_java
)
345 ; /* Proceed to language selection. */
356 eh_personality_libfunc
= init_one_libfunc (USING_SJLJ_EXCEPTIONS
357 ? "__gcj_personality_sj0"
358 : "__gcj_personality_v0");
367 error ("mixing C++ and Java catches in a single translation unit");
371 /* Initialize the catch parameter DECL. */
374 initialize_handler_parm (tree decl
, tree exp
)
379 /* Make sure we mark the catch param as used, otherwise we'll get a
380 warning about an unused ((anonymous)). */
381 TREE_USED (decl
) = 1;
383 /* Figure out the type that the initializer is. Pointers are returned
384 adjusted by value from __cxa_begin_catch. Others are returned by
386 init_type
= TREE_TYPE (decl
);
387 if (!POINTER_TYPE_P (init_type
))
388 init_type
= build_reference_type (init_type
);
390 choose_personality_routine (decl_is_java_type (init_type
, 0)
391 ? lang_java
: lang_cplusplus
);
393 /* Since pointers are passed by value, initialize a reference to
394 pointer catch parm with the address of the temporary. */
395 if (TREE_CODE (init_type
) == REFERENCE_TYPE
396 && TYPE_PTR_P (TREE_TYPE (init_type
)))
397 exp
= cp_build_unary_op (ADDR_EXPR
, exp
, 1, tf_warning_or_error
);
399 exp
= ocp_convert (init_type
, exp
, CONV_IMPLICIT
|CONV_FORCE_TEMP
, 0);
401 init
= convert_from_reference (exp
);
403 /* If the constructor for the catch parm exits via an exception, we
404 must call terminate. See eh23.C. */
405 if (TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl
)))
407 /* Generate the copy constructor call directly so we can wrap it.
408 See also expand_default_init. */
409 init
= ocp_convert (TREE_TYPE (decl
), init
,
410 CONV_IMPLICIT
|CONV_FORCE_TEMP
, 0);
411 /* Force cleanups now to avoid nesting problems with the
412 MUST_NOT_THROW_EXPR. */
413 init
= fold_build_cleanup_point_expr (TREE_TYPE (init
), init
);
414 init
= build1 (MUST_NOT_THROW_EXPR
, TREE_TYPE (init
), init
);
417 decl
= pushdecl (decl
);
419 start_decl_1 (decl
, true);
420 cp_finish_decl (decl
, init
, /*init_const_expr_p=*/false, NULL_TREE
,
421 LOOKUP_ONLYCONVERTING
|DIRECT_BIND
);
424 /* Call this to start a catch block. DECL is the catch parameter. */
427 expand_start_catch_block (tree decl
)
435 /* Make sure this declaration is reasonable. */
436 if (decl
&& !complete_ptr_ref_or_void_ptr_p (TREE_TYPE (decl
), NULL_TREE
))
437 decl
= error_mark_node
;
440 type
= prepare_eh_type (TREE_TYPE (decl
));
444 if (decl
&& decl_is_java_type (type
, 1))
446 /* Java only passes object via pointer and doesn't require
447 adjusting. The java object is immediately before the
448 generic exception header. */
449 exp
= build_exc_ptr ();
450 exp
= build1 (NOP_EXPR
, build_pointer_type (type
), exp
);
451 exp
= build2 (POINTER_PLUS_EXPR
, TREE_TYPE (exp
), exp
,
452 fold_build1 (NEGATE_EXPR
, sizetype
,
453 TYPE_SIZE_UNIT (TREE_TYPE (exp
))));
454 exp
= cp_build_indirect_ref (exp
, NULL
, tf_warning_or_error
);
455 initialize_handler_parm (decl
, exp
);
459 /* Call __cxa_end_catch at the end of processing the exception. */
460 push_eh_cleanup (type
);
462 /* If there's no decl at all, then all we need to do is make sure
463 to tell the runtime that we've begun handling the exception. */
464 if (decl
== NULL
|| decl
== error_mark_node
)
465 finish_expr_stmt (do_begin_catch ());
467 /* If the C++ object needs constructing, we need to do that before
468 calling __cxa_begin_catch, so that std::uncaught_exception gets
469 the right value during the copy constructor. */
470 else if (flag_use_cxa_get_exception_ptr
471 && TYPE_NEEDS_CONSTRUCTING (TREE_TYPE (decl
)))
473 exp
= do_get_exception_ptr ();
474 initialize_handler_parm (decl
, exp
);
475 finish_expr_stmt (do_begin_catch ());
478 /* Otherwise the type uses a bitwise copy, and we don't have to worry
479 about the value of std::uncaught_exception and therefore can do the
480 copy with the return value of __cxa_end_catch instead. */
483 tree init
= do_begin_catch ();
484 tree init_type
= type
;
486 /* Pointers are passed by values, everything else by reference. */
487 if (!TYPE_PTR_P (type
))
488 init_type
= build_pointer_type (type
);
489 if (init_type
!= TREE_TYPE (init
))
490 init
= build1 (NOP_EXPR
, init_type
, init
);
491 exp
= create_temporary_var (init_type
);
492 DECL_REGISTER (exp
) = 1;
493 cp_finish_decl (exp
, init
, /*init_const_expr=*/false,
494 NULL_TREE
, LOOKUP_ONLYCONVERTING
);
495 initialize_handler_parm (decl
, exp
);
502 /* Call this to end a catch block. Its responsible for emitting the
503 code to handle jumping back to the correct place, and for emitting
504 the label to jump to if this catch block didn't match. */
507 expand_end_catch_block (void)
512 /* The exception being handled is rethrown if control reaches the end of
513 a handler of the function-try-block of a constructor or destructor. */
514 if (in_function_try_handler
515 && (DECL_CONSTRUCTOR_P (current_function_decl
)
516 || DECL_DESTRUCTOR_P (current_function_decl
)))
517 finish_expr_stmt (build_throw (NULL_TREE
));
521 begin_eh_spec_block (void)
523 tree r
= build_stmt (EH_SPEC_BLOCK
, NULL_TREE
, NULL_TREE
);
525 EH_SPEC_STMTS (r
) = push_stmt_list ();
530 finish_eh_spec_block (tree raw_raises
, tree eh_spec_block
)
534 EH_SPEC_STMTS (eh_spec_block
) = pop_stmt_list (EH_SPEC_STMTS (eh_spec_block
));
536 /* Strip cv quals, etc, from the specification types. */
537 for (raises
= NULL_TREE
;
538 raw_raises
&& TREE_VALUE (raw_raises
);
539 raw_raises
= TREE_CHAIN (raw_raises
))
541 tree type
= prepare_eh_type (TREE_VALUE (raw_raises
));
542 tree tinfo
= eh_type_info (type
);
545 raises
= tree_cons (NULL_TREE
, type
, raises
);
548 EH_SPEC_RAISES (eh_spec_block
) = raises
;
551 /* Return a pointer to a buffer for an exception object of type TYPE. */
554 do_allocate_exception (tree type
)
558 fn
= get_identifier ("__cxa_allocate_exception");
559 if (!get_global_value_if_present (fn
, &fn
))
561 /* Declare void *__cxa_allocate_exception(size_t) throw(). */
562 fn
= declare_nothrow_library_fn (fn
, ptr_type_node
, size_type_node
);
565 return cp_build_function_call (fn
,
566 tree_cons (NULL_TREE
, size_in_bytes (type
),
568 tf_warning_or_error
);
571 /* Call __cxa_free_exception from a cleanup. This is never invoked
572 directly, but see the comment for stabilize_throw_expr. */
575 do_free_exception (tree ptr
)
579 fn
= get_identifier ("__cxa_free_exception");
580 if (!get_global_value_if_present (fn
, &fn
))
582 /* Declare void __cxa_free_exception (void *) throw(). */
583 fn
= declare_nothrow_library_fn (fn
, void_type_node
, ptr_type_node
);
586 return cp_build_function_call (fn
, tree_cons (NULL_TREE
, ptr
, NULL_TREE
),
587 tf_warning_or_error
);
590 /* Wrap all cleanups for TARGET_EXPRs in MUST_NOT_THROW_EXPR.
591 Called from build_throw via walk_tree_without_duplicates. */
594 wrap_cleanups_r (tree
*tp
, int *walk_subtrees ATTRIBUTE_UNUSED
,
595 void *data ATTRIBUTE_UNUSED
)
600 /* Don't walk into types. */
606 if (TREE_CODE (exp
) != TARGET_EXPR
)
609 cleanup
= TARGET_EXPR_CLEANUP (exp
);
612 cleanup
= build1 (MUST_NOT_THROW_EXPR
, void_type_node
, cleanup
);
613 TARGET_EXPR_CLEANUP (exp
) = cleanup
;
616 /* Keep iterating. */
620 /* Build a throw expression. */
623 build_throw (tree exp
)
627 if (exp
== error_mark_node
)
630 if (processing_template_decl
)
633 current_function_returns_abnormally
= 1;
634 return build_min (THROW_EXPR
, void_type_node
, exp
);
637 if (exp
== null_node
)
638 warning (0, "throwing NULL, which has integral, not pointer type");
640 if (exp
!= NULL_TREE
)
642 if (!is_admissible_throw_operand (exp
))
643 return error_mark_node
;
647 return error_mark_node
;
649 if (exp
&& decl_is_java_type (TREE_TYPE (exp
), 1))
651 tree fn
= get_identifier ("_Jv_Throw");
652 if (!get_global_value_if_present (fn
, &fn
))
654 /* Declare void _Jv_Throw (void *). */
655 tree tmp
= tree_cons (NULL_TREE
, ptr_type_node
, void_list_node
);
656 tmp
= build_function_type (ptr_type_node
, tmp
);
657 fn
= push_throw_library_fn (fn
, tmp
);
659 else if (really_overloaded_fn (fn
))
661 error ("%qD should never be overloaded", fn
);
662 return error_mark_node
;
664 fn
= OVL_CURRENT (fn
);
665 exp
= cp_build_function_call (fn
, tree_cons (NULL_TREE
, exp
, NULL_TREE
),
666 tf_warning_or_error
);
675 tree temp_expr
, allocate_expr
;
678 /* The CLEANUP_TYPE is the internal type of a destructor. */
681 tmp
= void_list_node
;
682 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, tmp
);
683 tmp
= build_function_type (void_type_node
, tmp
);
684 cleanup_type
= build_pointer_type (tmp
);
687 fn
= get_identifier ("__cxa_throw");
688 if (!get_global_value_if_present (fn
, &fn
))
690 /* Declare void __cxa_throw (void*, void*, void (*)(void*)). */
691 /* ??? Second argument is supposed to be "std::type_info*". */
692 tmp
= void_list_node
;
693 tmp
= tree_cons (NULL_TREE
, cleanup_type
, tmp
);
694 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, tmp
);
695 tmp
= tree_cons (NULL_TREE
, ptr_type_node
, tmp
);
696 tmp
= build_function_type (void_type_node
, tmp
);
697 fn
= push_throw_library_fn (fn
, tmp
);
702 A throw-expression initializes a temporary object, the type
703 of which is determined by removing any top-level
704 cv-qualifiers from the static type of the operand of throw
705 and adjusting the type from "array of T" or "function return
706 T" to "pointer to T" or "pointer to function returning T"
708 temp_type
= is_bitfield_expr_with_lowered_type (exp
);
710 temp_type
= type_decays_to (TREE_TYPE (exp
));
712 /* OK, this is kind of wacky. The standard says that we call
713 terminate when the exception handling mechanism, after
714 completing evaluation of the expression to be thrown but
715 before the exception is caught (_except.throw_), calls a
716 user function that exits via an uncaught exception.
718 So we have to protect the actual initialization of the
719 exception object with terminate(), but evaluate the
720 expression first. Since there could be temps in the
721 expression, we need to handle that, too. We also expand
722 the call to __cxa_allocate_exception first (which doesn't
723 matter, since it can't throw). */
725 /* Allocate the space for the exception. */
726 allocate_expr
= do_allocate_exception (temp_type
);
727 allocate_expr
= get_target_expr (allocate_expr
);
728 ptr
= TARGET_EXPR_SLOT (allocate_expr
);
729 object
= build_nop (build_pointer_type (temp_type
), ptr
);
730 object
= cp_build_indirect_ref (object
, NULL
, tf_warning_or_error
);
732 elided
= (TREE_CODE (exp
) == TARGET_EXPR
);
734 /* And initialize the exception object. */
735 if (CLASS_TYPE_P (temp_type
))
737 int flags
= LOOKUP_NORMAL
| LOOKUP_ONLYCONVERTING
;
739 /* Under C++0x [12.8/16 class.copy], a thrown lvalue is sometimes
740 treated as an rvalue for the purposes of overload resolution
741 to favor move constructors over copy constructors. */
742 if (/* Must be a local, automatic variable. */
743 TREE_CODE (exp
) == VAR_DECL
744 && DECL_CONTEXT (exp
) == current_function_decl
745 && ! TREE_STATIC (exp
)
746 /* The variable must not have the `volatile' qualifier. */
747 && !(cp_type_quals (TREE_TYPE (exp
)) & TYPE_QUAL_VOLATILE
))
748 flags
= flags
| LOOKUP_PREFER_RVALUE
;
750 /* Call the copy constructor. */
751 exp
= (build_special_member_call
752 (object
, complete_ctor_identifier
,
753 build_tree_list (NULL_TREE
, exp
),
755 flags
, tf_warning_or_error
));
756 if (exp
== error_mark_node
)
758 error (" in thrown expression");
759 return error_mark_node
;
763 exp
= build2 (INIT_EXPR
, temp_type
, object
,
764 decay_conversion (exp
));
766 /* Pre-evaluate the thrown expression first, since if we allocated
767 the space first we would have to deal with cleaning it up if
768 evaluating this expression throws.
770 The case where EXP the initializer is a cast or a function
771 returning a class is a bit of a grey area in the standard; it's
772 unclear whether or not it should be allowed to throw. We used to
773 say no, as that allowed us to optimize this case without worrying
774 about deallocating the exception object if it does. But that
775 conflicted with expectations (PR 13944) and the EDG compiler; now
776 we wrap the initialization in a TRY_CATCH_EXPR to call
777 do_free_exception rather than in a MUST_NOT_THROW_EXPR, for this
780 BUT: Issue 475 may do away with this inconsistency by removing the
781 terminate() in this situation.
783 Note that we don't check the return value from stabilize_init
784 because it will only return false in cases where elided is true,
785 and therefore we don't need to work around the failure to
787 temp_expr
= NULL_TREE
;
788 stabilize_init (exp
, &temp_expr
);
790 /* Wrap the initialization in a CLEANUP_POINT_EXPR so that cleanups
791 for temporaries within the initialization are run before the one
792 for the exception object, preserving LIFO order. */
793 exp
= build1 (CLEANUP_POINT_EXPR
, void_type_node
, exp
);
796 exp
= build2 (TRY_CATCH_EXPR
, void_type_node
, exp
,
797 do_free_exception (ptr
));
799 exp
= build1 (MUST_NOT_THROW_EXPR
, void_type_node
, exp
);
801 /* Prepend the allocation. */
802 exp
= build2 (COMPOUND_EXPR
, TREE_TYPE (exp
), allocate_expr
, exp
);
805 /* Prepend the calculation of the throw expression. Also, force
806 any cleanups from the expression to be evaluated here so that
807 we don't have to do them during unwinding. But first wrap
808 them in MUST_NOT_THROW_EXPR, since they are run after the
809 exception object is initialized. */
810 cp_walk_tree_without_duplicates (&temp_expr
, wrap_cleanups_r
, 0);
811 exp
= build2 (COMPOUND_EXPR
, TREE_TYPE (exp
), temp_expr
, exp
);
812 exp
= build1 (CLEANUP_POINT_EXPR
, TREE_TYPE (exp
), exp
);
815 throw_type
= build_eh_type_type (prepare_eh_type (TREE_TYPE (object
)));
817 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (TREE_TYPE (object
)))
819 cleanup
= lookup_fnfields (TYPE_BINFO (TREE_TYPE (object
)),
820 complete_dtor_identifier
, 0);
821 cleanup
= BASELINK_FUNCTIONS (cleanup
);
823 cxx_mark_addressable (cleanup
);
824 /* Pretend it's a normal function. */
825 cleanup
= build1 (ADDR_EXPR
, cleanup_type
, cleanup
);
828 cleanup
= build_int_cst (cleanup_type
, 0);
830 tmp
= tree_cons (NULL_TREE
, cleanup
, NULL_TREE
);
831 tmp
= tree_cons (NULL_TREE
, throw_type
, tmp
);
832 tmp
= tree_cons (NULL_TREE
, ptr
, tmp
);
833 /* ??? Indicate that this function call throws throw_type. */
834 tmp
= cp_build_function_call (fn
, tmp
, tf_warning_or_error
);
836 /* Tack on the initialization stuff. */
837 exp
= build2 (COMPOUND_EXPR
, TREE_TYPE (tmp
), exp
, tmp
);
841 /* Rethrow current exception. */
843 tree fn
= get_identifier ("__cxa_rethrow");
844 if (!get_global_value_if_present (fn
, &fn
))
846 /* Declare void __cxa_rethrow (void). */
847 fn
= push_throw_library_fn
848 (fn
, build_function_type (void_type_node
, void_list_node
));
851 /* ??? Indicate that this function call allows exceptions of the type
852 of the enclosing catch block (if known). */
853 exp
= cp_build_function_call (fn
, NULL_TREE
, tf_warning_or_error
);
856 exp
= build1 (THROW_EXPR
, void_type_node
, exp
);
861 /* Make sure TYPE is complete, pointer to complete, reference to
862 complete, or pointer to cv void. Issue diagnostic on failure.
863 Return the zero on failure and nonzero on success. FROM can be
864 the expr or decl from whence TYPE came, if available. */
867 complete_ptr_ref_or_void_ptr_p (tree type
, tree from
)
871 /* Check complete. */
872 type
= complete_type_or_else (type
, from
);
876 /* Or a pointer or ref to one, or cv void *. */
877 is_ptr
= TREE_CODE (type
) == POINTER_TYPE
;
878 if (is_ptr
|| TREE_CODE (type
) == REFERENCE_TYPE
)
880 tree core
= TREE_TYPE (type
);
882 if (is_ptr
&& VOID_TYPE_P (core
))
884 else if (!complete_type_or_else (core
, from
))
890 /* Return truth-value if EXPRESSION is admissible in throw-expression,
891 i.e. if it is not of incomplete type or a pointer/reference to such
892 a type or of an abstract class type. */
895 is_admissible_throw_operand (tree expr
)
897 tree type
= TREE_TYPE (expr
);
899 /* 15.1/4 [...] The type of the throw-expression shall not be an
900 incomplete type, or a pointer or a reference to an incomplete
901 type, other than void*, const void*, volatile void*, or
902 const volatile void*. Except for these restriction and the
903 restrictions on type matching mentioned in 15.3, the operand
904 of throw is treated exactly as a function argument in a call
905 (5.2.2) or the operand of a return statement. */
906 if (!complete_ptr_ref_or_void_ptr_p (type
, expr
))
909 /* 10.4/3 An abstract class shall not be used as a parameter type,
910 as a function return type or as type of an explicit
912 else if (CLASS_TYPE_P (type
) && CLASSTYPE_PURE_VIRTUALS (type
))
914 error ("expression %qE of abstract class type %qT cannot "
915 "be used in throw-expression", expr
, type
);
922 /* Returns nonzero if FN is a declaration of a standard C library
923 function which is known not to throw.
925 [lib.res.on.exception.handling]: None of the functions from the
926 Standard C library shall report an error by throwing an
927 exception, unless it calls a program-supplied function that
928 throws an exception. */
933 nothrow_libfn_p (const_tree fn
)
938 && DECL_EXTERNAL (fn
)
939 && DECL_NAMESPACE_SCOPE_P (fn
)
940 && DECL_EXTERN_C_P (fn
))
943 /* Can't be a C library function. */
946 /* Being a C library function, DECL_ASSEMBLER_NAME == DECL_NAME
947 unless the system headers are playing rename tricks, and if
948 they are, we don't want to be confused by them. */
950 return !!libc_name_p (IDENTIFIER_POINTER (id
), IDENTIFIER_LENGTH (id
));
953 /* Returns nonzero if an exception of type FROM will be caught by a
954 handler for type TO, as per [except.handle]. */
957 can_convert_eh (tree to
, tree from
)
959 to
= non_reference (to
);
960 from
= non_reference (from
);
962 if (TREE_CODE (to
) == POINTER_TYPE
&& TREE_CODE (from
) == POINTER_TYPE
)
965 from
= TREE_TYPE (from
);
967 if (! at_least_as_qualified_p (to
, from
))
970 if (TREE_CODE (to
) == VOID_TYPE
)
973 /* Else fall through. */
976 if (CLASS_TYPE_P (to
) && CLASS_TYPE_P (from
)
977 && PUBLICLY_UNIQUELY_DERIVED_P (to
, from
))
983 /* Check whether any of the handlers in I are shadowed by another handler
984 accepting TYPE. Note that the shadowing may not be complete; even if
985 an exception of type B would be caught by a handler for A, there could
986 be a derived class C for which A is an ambiguous base but B is not, so
987 the handler for B would catch an exception of type C. */
990 check_handlers_1 (tree master
, tree_stmt_iterator i
)
992 tree type
= TREE_TYPE (master
);
994 for (; !tsi_end_p (i
); tsi_next (&i
))
996 tree handler
= tsi_stmt (i
);
997 if (TREE_TYPE (handler
) && can_convert_eh (type
, TREE_TYPE (handler
)))
999 warning (0, "%Hexception of type %qT will be caught",
1000 EXPR_LOCUS (handler
), TREE_TYPE (handler
));
1001 warning (0, "%H by earlier handler for %qT",
1002 EXPR_LOCUS (master
), type
);
1008 /* Given a STATEMENT_LIST of HANDLERs, make sure that they're OK. */
1011 check_handlers (tree handlers
)
1013 tree_stmt_iterator i
;
1015 /* If we don't have a STATEMENT_LIST, then we've just got one
1016 handler, and thus nothing to warn about. */
1017 if (TREE_CODE (handlers
) != STATEMENT_LIST
)
1020 i
= tsi_start (handlers
);
1024 tree handler
= tsi_stmt (i
);
1027 /* No more handlers; nothing to shadow. */
1030 if (TREE_TYPE (handler
) == NULL_TREE
)
1031 permerror ("%H%<...%> handler must be the last handler for"
1032 " its try block", EXPR_LOCUS (handler
));
1034 check_handlers_1 (handler
, i
);