gcc/except.h

   1 /* Exception Handling interface routines.
   2    Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
   3    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 2, 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 COPYING.  If not, write to the Free
  20 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  21 02111-1307, USA.  */
  22
  23
  24 struct function;
  25
  26 struct inline_remap;
  27
  28 /* Per-function EH data.  Used only in except.c, but GC and others
  29    manipulate pointers to the opaque type.  */
  30 struct eh_status;
  31
  32 /* Internal structure describing a region.  */
  33 struct eh_region;
  34
  35 /* Test: is exception handling turned on?  */
  36 extern int doing_eh (int);
  37
  38 /* Start an exception handling region.  All instructions emitted after
  39    this point are considered to be part of the region until an
  40    expand_eh_region_end variant is invoked.  */
  41 extern void expand_eh_region_start (void);
  42
  43 /* End an exception handling region for a cleanup.  HANDLER is an
  44    expression to expand for the cleanup.  */
  45 extern void expand_eh_region_end_cleanup (tree);
  46
  47 /* End an exception handling region for a try block, and prepares
  48    for subsequent calls to expand_start_catch.  */
  49 extern void expand_start_all_catch (void);
  50
  51 /* Begin a catch clause.  TYPE is an object to be matched by the
  52    runtime, or a list of such objects, or null if this is a catch-all
  53    clause.  */
  54 extern void expand_start_catch (tree);
  55
  56 /* End a catch clause.  Control will resume after the try/catch block.  */
  57 extern void expand_end_catch (void);
  58
  59 /* End a sequence of catch handlers for a try block.  */
  60 extern void expand_end_all_catch (void);
  61
  62 /* End an exception region for an exception type filter.  ALLOWED is a
  63    TREE_LIST of TREE_VALUE objects to be matched by the runtime.
  64    FAILURE is a function to invoke if a mismatch occurs.  */
  65 extern void expand_eh_region_end_allowed (tree, tree);
  66
  67 /* End an exception region for a must-not-throw filter.  FAILURE is a
  68    function to invoke if an uncaught exception propagates this far.  */
  69 extern void expand_eh_region_end_must_not_throw (tree);
  70
  71 /* End an exception region for a throw.  No handling goes on here,
  72    but it's the easiest way for the front-end to indicate what type
  73    is being thrown.  */
  74 extern void expand_eh_region_end_throw (tree);
  75
  76 /* End a fixup region.  Within this region the cleanups for the immediately
  77    enclosing region are _not_ run.  This is used for goto cleanup to avoid
  78    destroying an object twice.  */
  79 extern void expand_eh_region_end_fixup (tree);
  80
  81 /* Note that the current EH region (if any) may contain a throw, or a
  82    call to a function which itself may contain a throw.  */
  83 extern void note_eh_region_may_contain_throw (void);
  84
  85 /* Invokes CALLBACK for every exception handler label.  Only used by old
  86    loop hackery; should not be used by new code.  */
  87 extern void for_each_eh_label (void (*) (rtx));
  88
  89 /* Determine if the given INSN can throw an exception.  */
  90 extern bool can_throw_internal (rtx);
  91 extern bool can_throw_external (rtx);
  92
  93 /* Set current_function_nothrow and cfun->all_throwers_are_sibcalls.  */
  94 extern void set_nothrow_function_flags (void);
  95
  96 /* After initial rtl generation, call back to finish generating
  97    exception support code.  */
  98 extern void finish_eh_generation (void);
  99
 100 extern void init_eh (void);
 101 extern void init_eh_for_function (void);
 102
 103 extern rtx reachable_handlers (rtx);
 104 extern void maybe_remove_eh_handler (rtx);
 105
 106 extern void convert_from_eh_region_ranges (void);
 107 extern void convert_to_eh_region_ranges (void);
 108 extern void find_exception_handler_labels (void);
 109 extern bool current_function_has_exception_handlers (void);
 110 extern void output_function_exception_table (void);
 111
 112 extern void expand_builtin_unwind_init (void);
 113 extern rtx expand_builtin_eh_return_data_regno (tree);
 114 extern rtx expand_builtin_extract_return_addr (tree);
 115 extern void expand_builtin_init_dwarf_reg_sizes (tree);
 116 extern rtx expand_builtin_frob_return_addr (tree);
 117 extern rtx expand_builtin_dwarf_sp_column (void);
 118 extern void expand_builtin_eh_return (tree, tree);
 119 extern void expand_eh_return (void);
 120 extern rtx get_exception_pointer (struct function *);
 121 extern int duplicate_eh_regions (struct function *, struct inline_remap *);
 122
 123 extern void sjlj_emit_function_exit_after (rtx);
 124
 125
 126 /* If non-NULL, this is a function that returns an expression to be
 127    executed if an unhandled exception is propagated out of a cleanup
 128    region.  For example, in C++, an exception thrown by a destructor
 129    during stack unwinding is required to result in a call to
 130    `std::terminate', so the C++ version of this function returns a
 131    CALL_EXPR for `std::terminate'.  */
 132 extern tree (*lang_protect_cleanup_actions) (void);
 133
 134 /* Return true if type A catches type B.  */
 135 extern int (*lang_eh_type_covers) (tree a, tree b);
 136
 137 /* Map a type to a runtime object to match type.  */
 138 extern tree (*lang_eh_runtime_type) (tree);
 139
 140
 141 /* Just because the user configured --with-sjlj-exceptions=no doesn't
 142    mean that we can use call frame exceptions.  Detect that the target
 143    has appropriate support.  */
 144
 145 #ifndef MUST_USE_SJLJ_EXCEPTIONS
 146 # if !(defined (EH_RETURN_DATA_REGNO)                   \
 147        && (defined (IA64_UNWIND_INFO)                   \
 148            || (DWARF2_UNWIND_INFO                       \
 149                && (defined (EH_RETURN_HANDLER_RTX)      \
 150                    || defined (HAVE_eh_return)))))
 151 #  define MUST_USE_SJLJ_EXCEPTIONS      1
 152 # else
 153 #  define MUST_USE_SJLJ_EXCEPTIONS      0
 154 # endif
 155 #endif
 156
 157 #ifdef CONFIG_SJLJ_EXCEPTIONS
 158 # if CONFIG_SJLJ_EXCEPTIONS == 1
 159 #  define USING_SJLJ_EXCEPTIONS         1
 160 # endif
 161 # if CONFIG_SJLJ_EXCEPTIONS == 0
 162 #  define USING_SJLJ_EXCEPTIONS         0
 163 #  ifndef EH_RETURN_DATA_REGNO
 164     #error "EH_RETURN_DATA_REGNO required"
 165 #  endif
 166 #  if !defined(EH_RETURN_HANDLER_RTX) && !defined(HAVE_eh_return)
 167     #error "EH_RETURN_HANDLER_RTX or eh_return required"
 168 #  endif
 169 #  if !defined(DWARF2_UNWIND_INFO) && !defined(IA64_UNWIND_INFO)
 170     #error "{DWARF2,IA64}_UNWIND_INFO required"
 171 #  endif
 172 # endif
 173 #else
 174 # define USING_SJLJ_EXCEPTIONS          MUST_USE_SJLJ_EXCEPTIONS
 175 #endif