gcc/except.h

   1 /* Exception Handling interface routines.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   3    2007  Free Software Foundation, Inc.
   4    Contributed by Mike Stump <mrs@cygnus.com>.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 3, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING3.  If not see
  20 <http://www.gnu.org/licenses/>.  */
  21
  22
  23 struct function;
  24
  25 /* Per-function EH data.  Used only in except.c, but GC and others
  26    manipulate pointers to the opaque type.  */
  27 struct eh_status;
  28
  29 /* Internal structure describing a region.  */
  30 struct eh_region;
  31
  32 /* Test: is exception handling turned on?  */
  33 extern int doing_eh (int);
  34
  35 /* Note that the current EH region (if any) may contain a throw, or a
  36    call to a function which itself may contain a throw.  */
  37 extern void note_eh_region_may_contain_throw (struct eh_region *);
  38
  39 /* Invokes CALLBACK for every exception handler label.  Only used by old
  40    loop hackery; should not be used by new code.  */
  41 extern void for_each_eh_label (void (*) (rtx));
  42
  43 /* Invokes CALLBACK for every exception region in the current function.  */
  44 extern void for_each_eh_region (void (*) (struct eh_region *));
  45
  46 /* Determine if the given INSN can throw an exception.  */
  47 extern bool can_throw_internal_1 (int, bool);
  48 extern bool can_throw_internal (const_rtx);
  49 extern bool can_throw_external_1 (int, bool);
  50 extern bool can_throw_external (const_rtx);
  51
  52 /* Set TREE_NOTHROW and cfun->all_throwers_are_sibcalls.  */
  53 extern unsigned int set_nothrow_function_flags (void);
  54
  55 /* After initial rtl generation, call back to finish generating
  56    exception support code.  */
  57 extern void finish_eh_generation (void);
  58
  59 extern void init_eh (void);
  60 extern void init_eh_for_function (void);
  61
  62 extern rtx reachable_handlers (rtx);
  63 extern void maybe_remove_eh_handler (rtx);
  64
  65 extern void convert_from_eh_region_ranges (void);
  66 extern unsigned int convert_to_eh_region_ranges (void);
  67 extern void find_exception_handler_labels (void);
  68 extern bool current_function_has_exception_handlers (void);
  69 extern void output_function_exception_table (const char *);
  70
  71 extern void expand_builtin_unwind_init (void);
  72 extern rtx expand_builtin_eh_return_data_regno (tree);
  73 extern rtx expand_builtin_extract_return_addr (tree);
  74 extern void expand_builtin_init_dwarf_reg_sizes (tree);
  75 extern rtx expand_builtin_frob_return_addr (tree);
  76 extern rtx expand_builtin_dwarf_sp_column (void);
  77 extern void expand_builtin_eh_return (tree, tree);
  78 extern void expand_eh_return (void);
  79 extern rtx expand_builtin_extend_pointer (tree);
  80 extern rtx get_exception_pointer (void);
  81 extern rtx get_exception_filter (void);
  82 typedef tree (*duplicate_eh_regions_map) (tree, void *);
  83 extern int duplicate_eh_regions (struct function *, duplicate_eh_regions_map,
  84                                  void *, int, int);
  85
  86 extern void sjlj_emit_function_exit_after (rtx);
  87 extern void default_init_unwind_resume_libfunc (void);
  88
  89 extern struct eh_region *gen_eh_region_cleanup (struct eh_region *,
  90                                                 struct eh_region *);
  91 extern struct eh_region *gen_eh_region_try (struct eh_region *);
  92 extern struct eh_region *gen_eh_region_catch (struct eh_region *, tree);
  93 extern struct eh_region *gen_eh_region_allowed (struct eh_region *, tree);
  94 extern struct eh_region *gen_eh_region_must_not_throw (struct eh_region *);
  95 extern int get_eh_region_number (struct eh_region *);
  96 extern bool get_eh_region_may_contain_throw (struct eh_region *);
  97 extern tree get_eh_region_tree_label (struct eh_region *);
  98 extern void set_eh_region_tree_label (struct eh_region *, tree);
  99
 100 extern void foreach_reachable_handler (int, bool,
 101                                        void (*) (struct eh_region *, void *),
 102                                        void *);
 103
 104 extern void collect_eh_region_array (void);
 105 extern void expand_resx_expr (tree);
 106 extern void verify_eh_tree (struct function *);
 107 extern void dump_eh_tree (FILE *, struct function *);
 108 extern bool eh_region_outer_p (struct function *, int, int);
 109 extern int eh_region_outermost (struct function *, int, int);
 110
 111 /* tree-eh.c */
 112 extern void add_stmt_to_eh_region_fn (struct function *, tree, int);
 113 extern bool remove_stmt_from_eh_region_fn (struct function *, tree);
 114 extern int lookup_stmt_eh_region_fn (struct function *, const_tree);
 115 extern int lookup_stmt_eh_region (const_tree);
 116 extern bool verify_eh_edges (tree);
 117
 118 /* If non-NULL, this is a function that returns an expression to be
 119    executed if an unhandled exception is propagated out of a cleanup
 120    region.  For example, in C++, an exception thrown by a destructor
 121    during stack unwinding is required to result in a call to
 122    `std::terminate', so the C++ version of this function returns a
 123    CALL_EXPR for `std::terminate'.  */
 124 extern tree (*lang_protect_cleanup_actions) (void);
 125
 126 /* Return true if type A catches type B.  */
 127 extern int (*lang_eh_type_covers) (tree a, tree b);
 128
 129 /* Map a type to a runtime object to match type.  */
 130 extern tree (*lang_eh_runtime_type) (tree);
 131
 132
 133 /* Just because the user configured --with-sjlj-exceptions=no doesn't
 134    mean that we can use call frame exceptions.  Detect that the target
 135    has appropriate support.  */
 136
 137 #ifndef MUST_USE_SJLJ_EXCEPTIONS
 138 # if defined (EH_RETURN_DATA_REGNO)                     \
 139        && (defined (TARGET_UNWIND_INFO)                 \
 140            || (DWARF2_UNWIND_INFO                       \
 141                && (defined (EH_RETURN_HANDLER_RTX)      \
 142                    || defined (HAVE_eh_return))))
 143 #  define MUST_USE_SJLJ_EXCEPTIONS      0
 144 # else
 145 #  define MUST_USE_SJLJ_EXCEPTIONS      1
 146 # endif
 147 #endif
 148
 149 #ifdef CONFIG_SJLJ_EXCEPTIONS
 150 # if CONFIG_SJLJ_EXCEPTIONS == 1
 151 #  define USING_SJLJ_EXCEPTIONS         1
 152 # endif
 153 # if CONFIG_SJLJ_EXCEPTIONS == 0
 154 #  define USING_SJLJ_EXCEPTIONS         0
 155 #  if !defined(EH_RETURN_DATA_REGNO)
 156     #error "EH_RETURN_DATA_REGNO required"
 157 #  endif
 158 #  if ! (defined(TARGET_UNWIND_INFO) || DWARF2_UNWIND_INFO)
 159     #error "{DWARF2,TARGET}_UNWIND_INFO required"
 160 #  endif
 161 #  if !defined(TARGET_UNWIND_INFO) \
 162         && !(defined(EH_RETURN_HANDLER_RTX) || defined(HAVE_eh_return))
 163     #error "EH_RETURN_HANDLER_RTX or eh_return required"
 164 #  endif
 165 /* Usually the above error checks will have already triggered an
 166    error, but backends may set MUST_USE_SJLJ_EXCEPTIONS for their own
 167    reasons.  */
 168 #  if MUST_USE_SJLJ_EXCEPTIONS
 169     #error "Must use SJLJ exceptions but configured not to"
 170 #  endif
 171 # endif
 172 #else
 173 # define USING_SJLJ_EXCEPTIONS          MUST_USE_SJLJ_EXCEPTIONS
 174 #endif
 175
 176 struct throw_stmt_node GTY(())
 177 {
 178   tree stmt;
 179   int region_nr;
 180 };
 181
 182 extern struct htab *get_eh_throw_stmt_table (struct function *);
 183 extern void set_eh_throw_stmt_table (struct function *, struct htab *);