1/* Exception Handling interface routines.
2   Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
3   Free Software Foundation, Inc.
4   Contributed by Mike Stump <mrs@cygnus.com>.
5
6This file is part of GCC.
7
8GCC is free software; you can redistribute it and/or modify it under
9the terms of the GNU General Public License as published by the Free
10Software Foundation; either version 2, or (at your option) any later
11version.
12
13GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14WARRANTY; without even the implied warranty of MERCHANTABILITY or
15FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16for more details.
17
18You should have received a copy of the GNU General Public License
19along with GCC; see the file COPYING.  If not, write to the Free
20Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
2102110-1301, USA.  */
22
23
24struct function;
25
26/* Per-function EH data.  Used only in except.c, but GC and others
27   manipulate pointers to the opaque type.  */
28struct eh_status;
29
30/* Internal structure describing a region.  */
31struct eh_region;
32
33/* Test: is exception handling turned on?  */
34extern int doing_eh (int);
35
36/* Note that the current EH region (if any) may contain a throw, or a
37   call to a function which itself may contain a throw.  */
38extern void note_eh_region_may_contain_throw (struct eh_region *);
39extern void note_current_region_may_contain_throw (void);
40
41/* Invokes CALLBACK for every exception handler label.  Only used by old
42   loop hackery; should not be used by new code.  */
43extern void for_each_eh_label (void (*) (rtx));
44
45/* Invokes CALLBACK for every exception region in the current function.  */
46extern void for_each_eh_region (void (*) (struct eh_region *));
47
48/* Determine if the given INSN can throw an exception.  */
49extern bool can_throw_internal_1 (int, bool);
50extern bool can_throw_internal (rtx);
51extern bool can_throw_external_1 (int, bool);
52extern bool can_throw_external (rtx);
53
54/* Set TREE_NOTHROW and cfun->all_throwers_are_sibcalls.  */
55extern unsigned int set_nothrow_function_flags (void);
56
57/* After initial rtl generation, call back to finish generating
58   exception support code.  */
59extern void finish_eh_generation (void);
60
61extern void init_eh (void);
62extern void init_eh_for_function (void);
63
64extern rtx reachable_handlers (rtx);
65extern void maybe_remove_eh_handler (rtx);
66
67extern void convert_from_eh_region_ranges (void);
68extern unsigned int convert_to_eh_region_ranges (void);
69extern void find_exception_handler_labels (void);
70extern bool current_function_has_exception_handlers (void);
71extern void output_function_exception_table (void);
72
73extern void expand_builtin_unwind_init (void);
74extern rtx expand_builtin_eh_return_data_regno (tree);
75extern rtx expand_builtin_extract_return_addr (tree);
76extern void expand_builtin_init_dwarf_reg_sizes (tree);
77extern rtx expand_builtin_frob_return_addr (tree);
78extern rtx expand_builtin_dwarf_sp_column (void);
79extern void expand_builtin_eh_return (tree, tree);
80extern void expand_eh_return (void);
81extern rtx expand_builtin_extend_pointer (tree);
82extern rtx get_exception_pointer (struct function *);
83extern rtx get_exception_filter (struct function *);
84typedef tree (*duplicate_eh_regions_map) (tree, void *);
85extern int duplicate_eh_regions (struct function *, duplicate_eh_regions_map,
86				 void *, int, int);
87
88extern void sjlj_emit_function_exit_after (rtx);
89extern void default_init_unwind_resume_libfunc (void);
90
91extern struct eh_region *gen_eh_region_cleanup (struct eh_region *,
92						struct eh_region *);
93extern struct eh_region *gen_eh_region_try (struct eh_region *);
94extern struct eh_region *gen_eh_region_catch (struct eh_region *, tree);
95extern struct eh_region *gen_eh_region_allowed (struct eh_region *, tree);
96extern struct eh_region *gen_eh_region_must_not_throw (struct eh_region *);
97extern int get_eh_region_number (struct eh_region *);
98extern bool get_eh_region_may_contain_throw (struct eh_region *);
99extern tree get_eh_region_tree_label (struct eh_region *);
100extern void set_eh_region_tree_label (struct eh_region *, tree);
101
102extern void foreach_reachable_handler (int, bool,
103				       void (*) (struct eh_region *, void *),
104				       void *);
105
106extern void collect_eh_region_array (void);
107extern void expand_resx_expr (tree);
108extern void verify_eh_tree (struct function *);
109extern void dump_eh_tree (FILE *, struct function *);
110extern bool eh_region_outer_p (struct function *, int, int);
111extern int eh_region_outermost (struct function *, int, int);
112
113/* tree-eh.c */
114extern void add_stmt_to_eh_region_fn (struct function *, tree, int);
115extern bool remove_stmt_from_eh_region_fn (struct function *, tree);
116extern int lookup_stmt_eh_region_fn (struct function *, tree);
117extern int lookup_stmt_eh_region (tree);
118extern bool verify_eh_edges (tree);
119
120/* If non-NULL, this is a function that returns an expression to be
121   executed if an unhandled exception is propagated out of a cleanup
122   region.  For example, in C++, an exception thrown by a destructor
123   during stack unwinding is required to result in a call to
124   `std::terminate', so the C++ version of this function returns a
125   CALL_EXPR for `std::terminate'.  */
126extern tree (*lang_protect_cleanup_actions) (void);
127
128/* Return true if type A catches type B.  */
129extern int (*lang_eh_type_covers) (tree a, tree b);
130
131/* Map a type to a runtime object to match type.  */
132extern tree (*lang_eh_runtime_type) (tree);
133
134
135/* Just because the user configured --with-sjlj-exceptions=no doesn't
136   mean that we can use call frame exceptions.  Detect that the target
137   has appropriate support.  */
138
139#ifndef MUST_USE_SJLJ_EXCEPTIONS
140# if !(defined (EH_RETURN_DATA_REGNO)			\
141       && (defined (TARGET_UNWIND_INFO)			\
142	   || (DWARF2_UNWIND_INFO			\
143	       && (defined (EH_RETURN_HANDLER_RTX)	\
144		   || defined (HAVE_eh_return)))))
145#  define MUST_USE_SJLJ_EXCEPTIONS	1
146# else
147#  define MUST_USE_SJLJ_EXCEPTIONS	0
148# endif
149#endif
150
151#ifdef CONFIG_SJLJ_EXCEPTIONS
152# if CONFIG_SJLJ_EXCEPTIONS == 1
153#  define USING_SJLJ_EXCEPTIONS		1
154# endif
155# if CONFIG_SJLJ_EXCEPTIONS == 0
156#  define USING_SJLJ_EXCEPTIONS		0
157#  ifndef EH_RETURN_DATA_REGNO
158    #error "EH_RETURN_DATA_REGNO required"
159#  endif
160#  if !defined(EH_RETURN_HANDLER_RTX) && !defined(HAVE_eh_return)
161    #error "EH_RETURN_HANDLER_RTX or eh_return required"
162#  endif
163#  if !defined(DWARF2_UNWIND_INFO) && !defined(TARGET_UNWIND_INFO)
164    #error "{DWARF2,TARGET}_UNWIND_INFO required"
165#  endif
166# endif
167#else
168# define USING_SJLJ_EXCEPTIONS		MUST_USE_SJLJ_EXCEPTIONS
169#endif
170
171struct throw_stmt_node GTY(())
172{
173  tree stmt;
174  int region_nr;
175};
176
177extern struct htab *get_eh_throw_stmt_table (struct function *);
178extern void set_eh_throw_stmt_table (struct function *, struct htab *);
179
180#ifdef ENABLE_CHECKING
181extern void verify_eh_throw_table_statements (void);
182#endif
183