gcc/unwind-generic.h

   1 /* Exception handling and frame unwind runtime interface routines.
   2    Copyright (C) 2001, 2003, 2004, 2006 Free Software Foundation, Inc.
   3
   4    This file is part of GCC.
   5
   6    GCC is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2, or (at your option)
   9    any later version.
  10
  11    GCC is distributed in the hope that it will be useful, but WITHOUT
  12    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  14    License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with GCC; see the file COPYING.  If not, write to the Free
  18    Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  19    02110-1301, USA.  */
  20
  21 /* As a special exception, if you include this header file into source
  22    files compiled by GCC, this header file does not by itself cause
  23    the resulting executable to be covered by the GNU General Public
  24    License.  This exception does not however invalidate any other
  25    reasons why the executable file might be covered by the GNU General
  26    Public License.  */
  27
  28 /* This is derived from the C++ ABI for IA-64.  Where we diverge
  29    for cross-architecture compatibility are noted with "@@@".  */
  30
  31 #ifndef _UNWIND_H
  32 #define _UNWIND_H
  33
  34 #ifndef HIDE_EXPORTS
  35 #pragma GCC visibility push(default)
  36 #endif
  37
  38 #ifdef __cplusplus
  39 extern "C" {
  40 #endif
  41
  42 /* Level 1: Base ABI  */
  43
  44 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  45    inefficient for 32-bit and smaller machines.  */
  46 typedef unsigned _Unwind_Word __attribute__((__mode__(__word__)));
  47 typedef signed _Unwind_Sword __attribute__((__mode__(__word__)));
  48 #if defined(__ia64__) && defined(__hpux__)
  49 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  50 #else
  51 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  52 #endif
  53 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  54
  55 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  56    consumer of an exception.  We'll go along with this for now even on
  57    32-bit machines.  We'll need to provide some other option for
  58    16-bit machines and for machines with > 8 bits per byte.  */
  59 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  60
  61 /* The unwind interface uses reason codes in several contexts to
  62    identify the reasons for failures or other actions.  */
  63 typedef enum
  64 {
  65   _URC_NO_REASON = 0,
  66   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  67   _URC_FATAL_PHASE2_ERROR = 2,
  68   _URC_FATAL_PHASE1_ERROR = 3,
  69   _URC_NORMAL_STOP = 4,
  70   _URC_END_OF_STACK = 5,
  71   _URC_HANDLER_FOUND = 6,
  72   _URC_INSTALL_CONTEXT = 7,
  73   _URC_CONTINUE_UNWIND = 8
  74 } _Unwind_Reason_Code;
  75
  76
  77 /* The unwind interface uses a pointer to an exception header object
  78    as its representation of an exception being thrown. In general, the
  79    full representation of an exception object is language- and
  80    implementation-specific, but it will be prefixed by a header
  81    understood by the unwind interface.  */
  82
  83 struct _Unwind_Exception;
  84
  85 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  86                                               struct _Unwind_Exception *);
  87
  88 struct _Unwind_Exception
  89 {
  90   _Unwind_Exception_Class exception_class;
  91   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  92   _Unwind_Word private_1;
  93   _Unwind_Word private_2;
  94
  95   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  96      Taking that literally does not make much sense generically.  Instead we
  97      provide the maximum alignment required by any type for the machine.  */
  98 } __attribute__((__aligned__));
  99
 100
 101 /* The ACTIONS argument to the personality routine is a bitwise OR of one
 102    or more of the following constants.  */
 103 typedef int _Unwind_Action;
 104
 105 #define _UA_SEARCH_PHASE        1
 106 #define _UA_CLEANUP_PHASE       2
 107 #define _UA_HANDLER_FRAME       4
 108 #define _UA_FORCE_UNWIND        8
 109 #define _UA_END_OF_STACK        16
 110
 111 /* The target can override this macro to define any back-end-specific
 112    attributes required for the lowest-level stack frame.  */
 113 #ifndef LIBGCC2_UNWIND_ATTRIBUTE
 114 #define LIBGCC2_UNWIND_ATTRIBUTE
 115 #endif
 116
 117 /* This is an opaque type used to refer to a system-specific data
 118    structure used by the system unwinder. This context is created and
 119    destroyed by the system, and passed to the personality routine
 120    during unwinding.  */
 121 struct _Unwind_Context;
 122
 123 /* Raise an exception, passing along the given exception object.  */
 124 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 125 _Unwind_RaiseException (struct _Unwind_Exception *);
 126
 127 /* Raise an exception for forced unwinding.  */
 128
 129 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 130      (int, _Unwind_Action, _Unwind_Exception_Class,
 131       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 132
 133 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 134 _Unwind_ForcedUnwind (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 135
 136 /* Helper to invoke the exception_cleanup routine.  */
 137 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 138
 139 /* Resume propagation of an existing exception.  This is used after
 140    e.g. executing cleanup code, and not to implement rethrowing.  */
 141 extern void LIBGCC2_UNWIND_ATTRIBUTE
 142 _Unwind_Resume (struct _Unwind_Exception *);
 143
 144 /* @@@ Resume propagation of a FORCE_UNWIND exception, or to rethrow
 145    a normal exception that was handled.  */
 146 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 147 _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
 148
 149 /* @@@ Use unwind data to perform a stack backtrace.  The trace callback
 150    is called for every stack frame in the call chain, but no cleanup
 151    actions are performed.  */
 152 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
 153      (struct _Unwind_Context *, void *);
 154
 155 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 156 _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
 157
 158 /* These functions are used for communicating information about the unwind
 159    context (i.e. the unwind descriptors and the user register state) between
 160    the unwind library and the personality routine and landing pad.  Only
 161    selected registers may be manipulated.  */
 162
 163 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 164 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 165
 166 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 167 extern _Unwind_Ptr _Unwind_GetIPInfo (struct _Unwind_Context *, int *);
 168 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 169
 170 /* @@@ Retrieve the CFA of the given context.  */
 171 extern _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *);
 172
 173 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 174
 175 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 176
 177
 178 /* The personality routine is the function in the C++ (or other language)
 179    runtime library which serves as an interface between the system unwind
 180    library and language-specific exception handling semantics.  It is
 181    specific to the code fragment described by an unwind info block, and
 182    it is always referenced via the pointer in the unwind info block, and
 183    hence it has no ABI-specified name.
 184
 185    Note that this implies that two different C++ implementations can
 186    use different names, and have different contents in the language
 187    specific data area.  Moreover, that the language specific data
 188    area contains no version info because name of the function invoked
 189    provides more effective versioning by detecting at link time the
 190    lack of code to handle the different data format.  */
 191
 192 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 193      (int, _Unwind_Action, _Unwind_Exception_Class,
 194       struct _Unwind_Exception *, struct _Unwind_Context *);
 195
 196 /* @@@ The following alternate entry points are for setjmp/longjmp
 197    based unwinding.  */
 198
 199 struct SjLj_Function_Context;
 200 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 201 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 202
 203 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 204 _Unwind_SjLj_RaiseException (struct _Unwind_Exception *);
 205 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 206 _Unwind_SjLj_ForcedUnwind (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 207 extern void LIBGCC2_UNWIND_ATTRIBUTE
 208 _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 209 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 210 _Unwind_SjLj_Resume_or_Rethrow (struct _Unwind_Exception *);
 211
 212 /* @@@ The following provide access to the base addresses for text
 213    and data-relative addressing in the LDSA.  In order to stay link
 214    compatible with the standard ABI for IA-64, we inline these.  */
 215
 216 #ifdef __ia64__
 217 #include <stdlib.h>
 218
 219 static inline _Unwind_Ptr
 220 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 221 {
 222   /* The GP is stored in R1.  */
 223   return _Unwind_GetGR (_C, 1);
 224 }
 225
 226 static inline _Unwind_Ptr
 227 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
 228 {
 229   abort ();
 230   return 0;
 231 }
 232
 233 /* @@@ Retrieve the Backing Store Pointer of the given context.  */
 234 extern _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *);
 235 #else
 236 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 237 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 238 #endif
 239
 240 /* @@@ Given an address, return the entry point of the function that
 241    contains it.  */
 242 extern void * _Unwind_FindEnclosingFunction (void *pc);
 243
 244 #ifndef __SIZEOF_LONG__
 245   #error "__SIZEOF_LONG__ macro not defined"
 246 #endif
 247
 248 #ifndef __SIZEOF_POINTER__
 249   #error "__SIZEOF_POINTER__ macro not defined"
 250 #endif
 251
 252
 253 /* leb128 type numbers have a potentially unlimited size.
 254    The target of the following definitions of _sleb128_t and _uleb128_t
 255    is to have efficient data types large enough to hold the leb128 type
 256    numbers used in the unwind code.
 257    Mostly these types will simply be defined to long and unsigned long
 258    except when a unsigned long data type on the target machine is not
 259    capable of storing a pointer.  */
 260
 261 #if __SIZEOF_LONG__ >= __SIZEOF_POINTER__
 262   typedef long _sleb128_t;
 263   typedef unsigned long _uleb128_t;
 264 #elif __SIZEOF_LONG_LONG__ >= __SIZEOF_POINTER__
 265   typedef long long _sleb128_t;
 266   typedef unsigned long long _uleb128_t;
 267 #else
 268 # error "What type shall we use for _sleb128_t?"
 269 #endif
 270
 271 #ifdef __cplusplus
 272 }
 273 #endif
 274
 275 #ifndef HIDE_EXPORTS
 276 #pragma GCC visibility pop
 277 #endif
 278
 279 #endif /* unwind.h */