gcc/unwind-generic.h

   1 /* Exception handling and frame unwind runtime interface routines.
   2    Copyright (C) 2001, 2003, 2004, 2006, 2008, 2009 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 3, 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    Under Section 7 of GPL version 3, you are granted additional
  17    permissions described in the GCC Runtime Library Exception, version
  18    3.1, as published by the Free Software Foundation.
  19
  20    You should have received a copy of the GNU General Public License and
  21    a copy of the GCC Runtime Library Exception along with this program;
  22    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23    <http://www.gnu.org/licenses/>.  */
  24
  25 /* This is derived from the C++ ABI for IA-64.  Where we diverge
  26    for cross-architecture compatibility are noted with "@@@".  */
  27
  28 #ifndef _UNWIND_H
  29 #define _UNWIND_H
  30
  31 #ifndef HIDE_EXPORTS
  32 #pragma GCC visibility push(default)
  33 #endif
  34
  35 #ifdef __cplusplus
  36 extern "C" {
  37 #endif
  38
  39 /* Level 1: Base ABI  */
  40
  41 /* @@@ The IA-64 ABI uses uint64 throughout.  Most places this is
  42    inefficient for 32-bit and smaller machines.  */
  43 typedef unsigned _Unwind_Word __attribute__((__mode__(__unwind_word__)));
  44 typedef signed _Unwind_Sword __attribute__((__mode__(__unwind_word__)));
  45 #if defined(__ia64__) && defined(__hpux__)
  46 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__word__)));
  47 #else
  48 typedef unsigned _Unwind_Ptr __attribute__((__mode__(__pointer__)));
  49 #endif
  50 typedef unsigned _Unwind_Internal_Ptr __attribute__((__mode__(__pointer__)));
  51
  52 /* @@@ The IA-64 ABI uses a 64-bit word to identify the producer and
  53    consumer of an exception.  We'll go along with this for now even on
  54    32-bit machines.  We'll need to provide some other option for
  55    16-bit machines and for machines with > 8 bits per byte.  */
  56 typedef unsigned _Unwind_Exception_Class __attribute__((__mode__(__DI__)));
  57
  58 /* The unwind interface uses reason codes in several contexts to
  59    identify the reasons for failures or other actions.  */
  60 typedef enum
  61 {
  62   _URC_NO_REASON = 0,
  63   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  64   _URC_FATAL_PHASE2_ERROR = 2,
  65   _URC_FATAL_PHASE1_ERROR = 3,
  66   _URC_NORMAL_STOP = 4,
  67   _URC_END_OF_STACK = 5,
  68   _URC_HANDLER_FOUND = 6,
  69   _URC_INSTALL_CONTEXT = 7,
  70   _URC_CONTINUE_UNWIND = 8
  71 } _Unwind_Reason_Code;
  72
  73
  74 /* The unwind interface uses a pointer to an exception header object
  75    as its representation of an exception being thrown. In general, the
  76    full representation of an exception object is language- and
  77    implementation-specific, but it will be prefixed by a header
  78    understood by the unwind interface.  */
  79
  80 struct _Unwind_Exception;
  81
  82 typedef void (*_Unwind_Exception_Cleanup_Fn) (_Unwind_Reason_Code,
  83                                               struct _Unwind_Exception *);
  84
  85 struct _Unwind_Exception
  86 {
  87   _Unwind_Exception_Class exception_class;
  88   _Unwind_Exception_Cleanup_Fn exception_cleanup;
  89   _Unwind_Word private_1;
  90   _Unwind_Word private_2;
  91
  92   /* @@@ The IA-64 ABI says that this structure must be double-word aligned.
  93      Taking that literally does not make much sense generically.  Instead we
  94      provide the maximum alignment required by any type for the machine.  */
  95 } __attribute__((__aligned__));
  96
  97
  98 /* The ACTIONS argument to the personality routine is a bitwise OR of one
  99    or more of the following constants.  */
 100 typedef int _Unwind_Action;
 101
 102 #define _UA_SEARCH_PHASE        1
 103 #define _UA_CLEANUP_PHASE       2
 104 #define _UA_HANDLER_FRAME       4
 105 #define _UA_FORCE_UNWIND        8
 106 #define _UA_END_OF_STACK        16
 107
 108 /* The target can override this macro to define any back-end-specific
 109    attributes required for the lowest-level stack frame.  */
 110 #ifndef LIBGCC2_UNWIND_ATTRIBUTE
 111 #define LIBGCC2_UNWIND_ATTRIBUTE
 112 #endif
 113
 114 /* This is an opaque type used to refer to a system-specific data
 115    structure used by the system unwinder. This context is created and
 116    destroyed by the system, and passed to the personality routine
 117    during unwinding.  */
 118 struct _Unwind_Context;
 119
 120 /* Raise an exception, passing along the given exception object.  */
 121 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 122 _Unwind_RaiseException (struct _Unwind_Exception *);
 123
 124 /* Raise an exception for forced unwinding.  */
 125
 126 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 127      (int, _Unwind_Action, _Unwind_Exception_Class,
 128       struct _Unwind_Exception *, struct _Unwind_Context *, void *);
 129
 130 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 131 _Unwind_ForcedUnwind (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 132
 133 /* Helper to invoke the exception_cleanup routine.  */
 134 extern void _Unwind_DeleteException (struct _Unwind_Exception *);
 135
 136 /* Resume propagation of an existing exception.  This is used after
 137    e.g. executing cleanup code, and not to implement rethrowing.  */
 138 extern void LIBGCC2_UNWIND_ATTRIBUTE
 139 _Unwind_Resume (struct _Unwind_Exception *);
 140
 141 /* @@@ Resume propagation of a FORCE_UNWIND exception, or to rethrow
 142    a normal exception that was handled.  */
 143 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 144 _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
 145
 146 /* @@@ Use unwind data to perform a stack backtrace.  The trace callback
 147    is called for every stack frame in the call chain, but no cleanup
 148    actions are performed.  */
 149 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)
 150      (struct _Unwind_Context *, void *);
 151
 152 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 153 _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
 154
 155 /* These functions are used for communicating information about the unwind
 156    context (i.e. the unwind descriptors and the user register state) between
 157    the unwind library and the personality routine and landing pad.  Only
 158    selected registers may be manipulated.  */
 159
 160 extern _Unwind_Word _Unwind_GetGR (struct _Unwind_Context *, int);
 161 extern void _Unwind_SetGR (struct _Unwind_Context *, int, _Unwind_Word);
 162
 163 extern _Unwind_Ptr _Unwind_GetIP (struct _Unwind_Context *);
 164 extern _Unwind_Ptr _Unwind_GetIPInfo (struct _Unwind_Context *, int *);
 165 extern void _Unwind_SetIP (struct _Unwind_Context *, _Unwind_Ptr);
 166
 167 /* @@@ Retrieve the CFA of the given context.  */
 168 extern _Unwind_Word _Unwind_GetCFA (struct _Unwind_Context *);
 169
 170 extern void *_Unwind_GetLanguageSpecificData (struct _Unwind_Context *);
 171
 172 extern _Unwind_Ptr _Unwind_GetRegionStart (struct _Unwind_Context *);
 173
 174
 175 /* The personality routine is the function in the C++ (or other language)
 176    runtime library which serves as an interface between the system unwind
 177    library and language-specific exception handling semantics.  It is
 178    specific to the code fragment described by an unwind info block, and
 179    it is always referenced via the pointer in the unwind info block, and
 180    hence it has no ABI-specified name.
 181
 182    Note that this implies that two different C++ implementations can
 183    use different names, and have different contents in the language
 184    specific data area.  Moreover, that the language specific data
 185    area contains no version info because name of the function invoked
 186    provides more effective versioning by detecting at link time the
 187    lack of code to handle the different data format.  */
 188
 189 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)
 190      (int, _Unwind_Action, _Unwind_Exception_Class,
 191       struct _Unwind_Exception *, struct _Unwind_Context *);
 192
 193 /* @@@ The following alternate entry points are for setjmp/longjmp
 194    based unwinding.  */
 195
 196 struct SjLj_Function_Context;
 197 extern void _Unwind_SjLj_Register (struct SjLj_Function_Context *);
 198 extern void _Unwind_SjLj_Unregister (struct SjLj_Function_Context *);
 199
 200 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 201 _Unwind_SjLj_RaiseException (struct _Unwind_Exception *);
 202 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 203 _Unwind_SjLj_ForcedUnwind (struct _Unwind_Exception *, _Unwind_Stop_Fn, void *);
 204 extern void LIBGCC2_UNWIND_ATTRIBUTE
 205 _Unwind_SjLj_Resume (struct _Unwind_Exception *);
 206 extern _Unwind_Reason_Code LIBGCC2_UNWIND_ATTRIBUTE
 207 _Unwind_SjLj_Resume_or_Rethrow (struct _Unwind_Exception *);
 208
 209 /* @@@ The following provide access to the base addresses for text
 210    and data-relative addressing in the LDSA.  In order to stay link
 211    compatible with the standard ABI for IA-64, we inline these.  */
 212
 213 #ifdef __ia64__
 214 #include <stdlib.h>
 215
 216 static inline _Unwind_Ptr
 217 _Unwind_GetDataRelBase (struct _Unwind_Context *_C)
 218 {
 219   /* The GP is stored in R1.  */
 220   return _Unwind_GetGR (_C, 1);
 221 }
 222
 223 static inline _Unwind_Ptr
 224 _Unwind_GetTextRelBase (struct _Unwind_Context *_C __attribute__ ((__unused__)))
 225 {
 226   abort ();
 227   return 0;
 228 }
 229
 230 /* @@@ Retrieve the Backing Store Pointer of the given context.  */
 231 extern _Unwind_Word _Unwind_GetBSP (struct _Unwind_Context *);
 232 #else
 233 extern _Unwind_Ptr _Unwind_GetDataRelBase (struct _Unwind_Context *);
 234 extern _Unwind_Ptr _Unwind_GetTextRelBase (struct _Unwind_Context *);
 235 #endif
 236
 237 /* @@@ Given an address, return the entry point of the function that
 238    contains it.  */
 239 extern void * _Unwind_FindEnclosingFunction (void *pc);
 240
 241 #ifndef __SIZEOF_LONG__
 242   #error "__SIZEOF_LONG__ macro not defined"
 243 #endif
 244
 245 #ifndef __SIZEOF_POINTER__
 246   #error "__SIZEOF_POINTER__ macro not defined"
 247 #endif
 248
 249
 250 /* leb128 type numbers have a potentially unlimited size.
 251    The target of the following definitions of _sleb128_t and _uleb128_t
 252    is to have efficient data types large enough to hold the leb128 type
 253    numbers used in the unwind code.
 254    Mostly these types will simply be defined to long and unsigned long
 255    except when a unsigned long data type on the target machine is not
 256    capable of storing a pointer.  */
 257
 258 #if __SIZEOF_LONG__ >= __SIZEOF_POINTER__
 259   typedef long _sleb128_t;
 260   typedef unsigned long _uleb128_t;
 261 #elif __SIZEOF_LONG_LONG__ >= __SIZEOF_POINTER__
 262   typedef long long _sleb128_t;
 263   typedef unsigned long long _uleb128_t;
 264 #else
 265 # error "What type shall we use for _sleb128_t?"
 266 #endif
 267
 268 #ifdef __cplusplus
 269 }
 270 #endif
 271
 272 #ifndef HIDE_EXPORTS
 273 #pragma GCC visibility pop
 274 #endif
 275
 276 #endif /* unwind.h */