gcc/except.h

   1 /* Exception Handling interface routines.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
   3    2007, 2008  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 #include "sbitmap.h"
  23 #include "vecprim.h"
  24
  25 struct function;
  26
  27 /* Per-function EH data.  Used only in except.c, but GC and others
  28    manipulate pointers to the opaque type.  */
  29 struct eh_status;
  30
  31 /* Internal structure describing a region.  */
  32 struct eh_region;
  33
  34 /* Test: is exception handling turned on?  */
  35 extern int doing_eh (int);
  36
  37 /* Note that the current EH region (if any) may contain a throw, or a
  38    call to a function which itself may contain a throw.  */
  39 extern void note_eh_region_may_contain_throw (struct eh_region *);
  40
  41 /* Invokes CALLBACK for every exception handler label.  Only used by old
  42    loop hackery; should not be used by new code.  */
  43 extern void for_each_eh_label (void (*) (rtx));
  44
  45 /* Invokes CALLBACK for every exception region in the current function.  */
  46 extern void for_each_eh_region (void (*) (struct eh_region *));
  47
  48 /* Determine if the given INSN can throw an exception.  */
  49 extern bool can_throw_internal_1 (int, bool, bool);
  50 extern bool can_throw_internal (const_rtx);
  51 extern bool can_throw_external_1 (int, bool, bool);
  52 extern bool can_throw_external (const_rtx);
  53
  54 /* Set TREE_NOTHROW and cfun->all_throwers_are_sibcalls.  */
  55 extern unsigned int set_nothrow_function_flags (void);
  56
  57 /* After initial rtl generation, call back to finish generating
  58    exception support code.  */
  59 extern void finish_eh_generation (void);
  60
  61 extern void init_eh (void);
  62 extern void init_eh_for_function (void);
  63
  64 extern rtx reachable_handlers (rtx);
  65 extern void maybe_remove_eh_handler (rtx);
  66 void remove_eh_region (int);
  67
  68 extern void convert_from_eh_region_ranges (void);
  69 extern unsigned int convert_to_eh_region_ranges (void);
  70 extern void find_exception_handler_labels (void);
  71 extern bool current_function_has_exception_handlers (void);
  72 extern void output_function_exception_table (const char *);
  73
  74 extern void expand_builtin_unwind_init (void);
  75 extern rtx expand_builtin_eh_return_data_regno (tree);
  76 extern rtx expand_builtin_extract_return_addr (tree);
  77 extern void expand_builtin_init_dwarf_reg_sizes (tree);
  78 extern rtx expand_builtin_frob_return_addr (tree);
  79 extern rtx expand_builtin_dwarf_sp_column (void);
  80 extern void expand_builtin_eh_return (tree, tree);
  81 extern void expand_eh_return (void);
  82 extern rtx expand_builtin_extend_pointer (tree);
  83 extern rtx get_exception_pointer (void);
  84 extern rtx get_exception_filter (void);
  85 typedef tree (*duplicate_eh_regions_map) (tree, void *);
  86 extern int duplicate_eh_regions (struct function *, duplicate_eh_regions_map,
  87                                  void *, int, int);
  88
  89 extern void sjlj_emit_function_exit_after (rtx);
  90 extern void default_init_unwind_resume_libfunc (void);
  91
  92 extern struct eh_region *gen_eh_region_cleanup (struct eh_region *,
  93                                                 struct eh_region *);
  94 extern struct eh_region *gen_eh_region_try (struct eh_region *);
  95 extern struct eh_region *gen_eh_region_catch (struct eh_region *, tree);
  96 extern struct eh_region *gen_eh_region_allowed (struct eh_region *, tree);
  97 extern struct eh_region *gen_eh_region_must_not_throw (struct eh_region *);
  98 extern int get_eh_region_number (struct eh_region *);
  99 extern bool get_eh_region_may_contain_throw (struct eh_region *);
 100 extern tree get_eh_region_tree_label (struct eh_region *);
 101 extern void set_eh_region_tree_label (struct eh_region *, tree);
 102
 103 extern void foreach_reachable_handler (int, bool, bool,
 104                                        void (*) (struct eh_region *, void *),
 105                                        void *);
 106
 107 extern void collect_eh_region_array (void);
 108 extern void expand_resx_expr (tree);
 109 extern void verify_eh_tree (struct function *);
 110 extern void dump_eh_tree (FILE *, struct function *);
 111 extern bool eh_region_outer_p (struct function *, int, int);
 112 extern int eh_region_outermost (struct function *, int, int);
 113
 114 /* If non-NULL, this is a function that returns an expression to be
 115    executed if an unhandled exception is propagated out of a cleanup
 116    region.  For example, in C++, an exception thrown by a destructor
 117    during stack unwinding is required to result in a call to
 118    `std::terminate', so the C++ version of this function returns a
 119    CALL_EXPR for `std::terminate'.  */
 120 extern gimple (*lang_protect_cleanup_actions) (void);
 121
 122 /* Return true if type A catches type B.  */
 123 extern int (*lang_eh_type_covers) (tree a, tree b);
 124
 125 /* Map a type to a runtime object to match type.  */
 126 extern tree (*lang_eh_runtime_type) (tree);
 127
 128
 129 /* Just because the user configured --with-sjlj-exceptions=no doesn't
 130    mean that we can use call frame exceptions.  Detect that the target
 131    has appropriate support.  */
 132
 133 #ifndef MUST_USE_SJLJ_EXCEPTIONS
 134 # if defined (EH_RETURN_DATA_REGNO)                     \
 135        && (defined (TARGET_UNWIND_INFO)                 \
 136            || (DWARF2_UNWIND_INFO                       \
 137                && (defined (EH_RETURN_HANDLER_RTX)      \
 138                    || defined (HAVE_eh_return))))
 139 #  define MUST_USE_SJLJ_EXCEPTIONS      0
 140 # else
 141 #  define MUST_USE_SJLJ_EXCEPTIONS      1
 142 # endif
 143 #endif
 144
 145 #ifdef CONFIG_SJLJ_EXCEPTIONS
 146 # if CONFIG_SJLJ_EXCEPTIONS == 1
 147 #  define USING_SJLJ_EXCEPTIONS         1
 148 # endif
 149 # if CONFIG_SJLJ_EXCEPTIONS == 0
 150 #  define USING_SJLJ_EXCEPTIONS         0
 151 #  if !defined(EH_RETURN_DATA_REGNO)
 152     #error "EH_RETURN_DATA_REGNO required"
 153 #  endif
 154 #  if ! (defined(TARGET_UNWIND_INFO) || DWARF2_UNWIND_INFO)
 155     #error "{DWARF2,TARGET}_UNWIND_INFO required"
 156 #  endif
 157 #  if !defined(TARGET_UNWIND_INFO) \
 158         && !(defined(EH_RETURN_HANDLER_RTX) || defined(HAVE_eh_return))
 159     #error "EH_RETURN_HANDLER_RTX or eh_return required"
 160 #  endif
 161 /* Usually the above error checks will have already triggered an
 162    error, but backends may set MUST_USE_SJLJ_EXCEPTIONS for their own
 163    reasons.  */
 164 #  if MUST_USE_SJLJ_EXCEPTIONS
 165     #error "Must use SJLJ exceptions but configured not to"
 166 #  endif
 167 # endif
 168 #else
 169 # define USING_SJLJ_EXCEPTIONS          MUST_USE_SJLJ_EXCEPTIONS
 170 #endif
 171
 172 struct throw_stmt_node GTY(())
 173 {
 174   gimple stmt;
 175   int region_nr;
 176 };
 177
 178 extern struct htab *get_eh_throw_stmt_table (struct function *);
 179 extern void set_eh_throw_stmt_table (struct function *, struct htab *);
 180 extern void remove_unreachable_regions (sbitmap, sbitmap);
 181 extern VEC(int,heap) * label_to_region_map (void);
 182 extern int num_eh_regions (void);