libunwind/include/unwind.h

   1 //===------------------------------- unwind.h -----------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //
   8 // C++ ABI Level 1 ABI documented at:
   9 //   https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef __UNWIND_H__
  14 #define __UNWIND_H__
  15
  16 #include <__libunwind_config.h>
  17
  18 #include <stdint.h>
  19 #include <stddef.h>
  20
  21 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__) && defined(_WIN32)
  22 #include <windows.h>
  23 #include <ntverp.h>
  24 #endif
  25
  26 #if defined(__APPLE__)
  27 #define LIBUNWIND_UNAVAIL __attribute__ (( unavailable ))
  28 #else
  29 #define LIBUNWIND_UNAVAIL
  30 #endif
  31
  32 typedef enum {
  33   _URC_NO_REASON = 0,
  34   _URC_OK = 0,
  35   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
  36   _URC_FATAL_PHASE2_ERROR = 2,
  37   _URC_FATAL_PHASE1_ERROR = 3,
  38   _URC_NORMAL_STOP = 4,
  39   _URC_END_OF_STACK = 5,
  40   _URC_HANDLER_FOUND = 6,
  41   _URC_INSTALL_CONTEXT = 7,
  42   _URC_CONTINUE_UNWIND = 8,
  43 #if defined(_LIBUNWIND_ARM_EHABI)
  44   _URC_FAILURE = 9
  45 #endif
  46 } _Unwind_Reason_Code;
  47
  48 typedef enum {
  49   _UA_SEARCH_PHASE = 1,
  50   _UA_CLEANUP_PHASE = 2,
  51   _UA_HANDLER_FRAME = 4,
  52   _UA_FORCE_UNWIND = 8,
  53   _UA_END_OF_STACK = 16 // gcc extension to C++ ABI
  54 } _Unwind_Action;
  55
  56 typedef struct _Unwind_Context _Unwind_Context;   // opaque
  57
  58 #if defined(_LIBUNWIND_ARM_EHABI)
  59 typedef uint32_t _Unwind_State;
  60
  61 static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME   = 0;
  62 static const _Unwind_State _US_UNWIND_FRAME_STARTING  = 1;
  63 static const _Unwind_State _US_UNWIND_FRAME_RESUME    = 2;
  64 static const _Unwind_State _US_ACTION_MASK            = 3;
  65 /* Undocumented flag for force unwinding. */
  66 static const _Unwind_State _US_FORCE_UNWIND           = 8;
  67
  68 typedef uint32_t _Unwind_EHT_Header;
  69
  70 struct _Unwind_Control_Block;
  71 typedef struct _Unwind_Control_Block _Unwind_Control_Block;
  72 typedef struct _Unwind_Control_Block _Unwind_Exception; /* Alias */
  73
  74 struct _Unwind_Control_Block {
  75   uint64_t exception_class;
  76   void (*exception_cleanup)(_Unwind_Reason_Code, _Unwind_Control_Block*);
  77
  78   /* Unwinder cache, private fields for the unwinder's use */
  79   struct {
  80     uint32_t reserved1; /* init reserved1 to 0, then don't touch */
  81     uint32_t reserved2;
  82     uint32_t reserved3;
  83     uint32_t reserved4;
  84     uint32_t reserved5;
  85   } unwinder_cache;
  86
  87   /* Propagation barrier cache (valid after phase 1): */
  88   struct {
  89     uint32_t sp;
  90     uint32_t bitpattern[5];
  91   } barrier_cache;
  92
  93   /* Cleanup cache (preserved over cleanup): */
  94   struct {
  95     uint32_t bitpattern[4];
  96   } cleanup_cache;
  97
  98   /* Pr cache (for pr's benefit): */
  99   struct {
 100     uint32_t fnstart; /* function start address */
 101     _Unwind_EHT_Header* ehtp; /* pointer to EHT entry header word */
 102     uint32_t additional;
 103     uint32_t reserved1;
 104   } pr_cache;
 105
 106   long long int :0; /* Enforce the 8-byte alignment */
 107 } __attribute__((__aligned__(8)));
 108
 109 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 110       (_Unwind_State state,
 111        _Unwind_Exception* exceptionObject,
 112        struct _Unwind_Context* context);
 113
 114 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)(
 115     _Unwind_State state, _Unwind_Exception *exceptionObject,
 116     struct _Unwind_Context *context);
 117 #else
 118 struct _Unwind_Context;   // opaque
 119 struct _Unwind_Exception; // forward declaration
 120 typedef struct _Unwind_Exception _Unwind_Exception;
 121
 122 struct _Unwind_Exception {
 123   uint64_t exception_class;
 124   void (*exception_cleanup)(_Unwind_Reason_Code reason,
 125                             _Unwind_Exception *exc);
 126 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
 127   uintptr_t private_[6];
 128 #else
 129   uintptr_t private_1; // non-zero means forced unwind
 130   uintptr_t private_2; // holds sp that phase1 found for phase2 to use
 131 #endif
 132 #if __SIZEOF_POINTER__ == 4
 133   // The implementation of _Unwind_Exception uses an attribute mode on the
 134   // above fields which has the side effect of causing this whole struct to
 135   // round up to 32 bytes in size (48 with SEH). To be more explicit, we add
 136   // pad fields added for binary compatibility.
 137   uint32_t reserved[3];
 138 #endif
 139   // The Itanium ABI requires that _Unwind_Exception objects are "double-word
 140   // aligned".  GCC has interpreted this to mean "use the maximum useful
 141   // alignment for the target"; so do we.
 142 } __attribute__((__aligned__));
 143
 144 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 145     (int version,
 146      _Unwind_Action actions,
 147      uint64_t exceptionClass,
 148      _Unwind_Exception* exceptionObject,
 149      struct _Unwind_Context* context,
 150      void* stop_parameter );
 151
 152 typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)(
 153     int version, _Unwind_Action actions, uint64_t exceptionClass,
 154     _Unwind_Exception *exceptionObject, struct _Unwind_Context *context);
 155 #endif
 156
 157 #ifdef __cplusplus
 158 extern "C" {
 159 #endif
 160
 161 //
 162 // The following are the base functions documented by the C++ ABI
 163 //
 164 #ifdef __USING_SJLJ_EXCEPTIONS__
 165 extern _Unwind_Reason_Code
 166     _Unwind_SjLj_RaiseException(_Unwind_Exception *exception_object);
 167 extern void _Unwind_SjLj_Resume(_Unwind_Exception *exception_object);
 168 #else
 169 extern _Unwind_Reason_Code
 170     _Unwind_RaiseException(_Unwind_Exception *exception_object);
 171 extern void _Unwind_Resume(_Unwind_Exception *exception_object);
 172 #endif
 173 extern void _Unwind_DeleteException(_Unwind_Exception *exception_object);
 174
 175 #if defined(_LIBUNWIND_ARM_EHABI)
 176 typedef enum {
 177   _UVRSC_CORE = 0, /* integer register */
 178   _UVRSC_VFP = 1, /* vfp */
 179   _UVRSC_WMMXD = 3, /* Intel WMMX data register */
 180   _UVRSC_WMMXC = 4 /* Intel WMMX control register */
 181 } _Unwind_VRS_RegClass;
 182
 183 typedef enum {
 184   _UVRSD_UINT32 = 0,
 185   _UVRSD_VFPX = 1,
 186   _UVRSD_UINT64 = 3,
 187   _UVRSD_FLOAT = 4,
 188   _UVRSD_DOUBLE = 5
 189 } _Unwind_VRS_DataRepresentation;
 190
 191 typedef enum {
 192   _UVRSR_OK = 0,
 193   _UVRSR_NOT_IMPLEMENTED = 1,
 194   _UVRSR_FAILED = 2
 195 } _Unwind_VRS_Result;
 196
 197 extern void _Unwind_Complete(_Unwind_Exception* exception_object);
 198
 199 extern _Unwind_VRS_Result
 200 _Unwind_VRS_Get(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
 201                 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
 202                 void *valuep);
 203
 204 extern _Unwind_VRS_Result
 205 _Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
 206                 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
 207                 void *valuep);
 208
 209 extern _Unwind_VRS_Result
 210 _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
 211                 uint32_t discriminator,
 212                 _Unwind_VRS_DataRepresentation representation);
 213 #endif
 214
 215 #if !defined(_LIBUNWIND_ARM_EHABI)
 216
 217 extern uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index);
 218 extern void _Unwind_SetGR(struct _Unwind_Context *context, int index,
 219                           uintptr_t new_value);
 220 extern uintptr_t _Unwind_GetIP(struct _Unwind_Context *context);
 221 extern void _Unwind_SetIP(struct _Unwind_Context *, uintptr_t new_value);
 222
 223 #else  // defined(_LIBUNWIND_ARM_EHABI)
 224
 225 #if defined(_LIBUNWIND_UNWIND_LEVEL1_EXTERNAL_LINKAGE)
 226 #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 extern
 227 #else
 228 #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 static __inline__
 229 #endif
 230
 231 // These are de facto helper functions for ARM, which delegate the function
 232 // calls to _Unwind_VRS_Get/Set().  These are not a part of ARM EHABI
 233 // specification, thus these function MUST be inlined.  Please don't replace
 234 // these with the "extern" function declaration; otherwise, the program
 235 // including this <unwind.h> header won't be ABI compatible and will result in
 236 // link error when we are linking the program with libgcc.
 237
 238 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 239 uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index) {
 240   uintptr_t value = 0;
 241   _Unwind_VRS_Get(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
 242   return value;
 243 }
 244
 245 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 246 void _Unwind_SetGR(struct _Unwind_Context *context, int index,
 247                    uintptr_t value) {
 248   _Unwind_VRS_Set(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
 249 }
 250
 251 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 252 uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) {
 253   // remove the thumb-bit before returning
 254   return _Unwind_GetGR(context, 15) & (~(uintptr_t)0x1);
 255 }
 256
 257 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 258 void _Unwind_SetIP(struct _Unwind_Context *context, uintptr_t value) {
 259   uintptr_t thumb_bit = _Unwind_GetGR(context, 15) & ((uintptr_t)0x1);
 260   _Unwind_SetGR(context, 15, value | thumb_bit);
 261 }
 262 #endif  // defined(_LIBUNWIND_ARM_EHABI)
 263
 264 extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context);
 265 extern uintptr_t
 266     _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context);
 267 #ifdef __USING_SJLJ_EXCEPTIONS__
 268 extern _Unwind_Reason_Code
 269     _Unwind_SjLj_ForcedUnwind(_Unwind_Exception *exception_object,
 270                               _Unwind_Stop_Fn stop, void *stop_parameter);
 271 #else
 272 extern _Unwind_Reason_Code
 273     _Unwind_ForcedUnwind(_Unwind_Exception *exception_object,
 274                          _Unwind_Stop_Fn stop, void *stop_parameter);
 275 #endif
 276
 277 #ifdef __USING_SJLJ_EXCEPTIONS__
 278 typedef struct _Unwind_FunctionContext *_Unwind_FunctionContext_t;
 279 extern void _Unwind_SjLj_Register(_Unwind_FunctionContext_t fc);
 280 extern void _Unwind_SjLj_Unregister(_Unwind_FunctionContext_t fc);
 281 #endif
 282
 283 //
 284 // The following are semi-suppoted extensions to the C++ ABI
 285 //
 286
 287 //
 288 //  called by __cxa_rethrow().
 289 //
 290 #ifdef __USING_SJLJ_EXCEPTIONS__
 291 extern _Unwind_Reason_Code
 292     _Unwind_SjLj_Resume_or_Rethrow(_Unwind_Exception *exception_object);
 293 #else
 294 extern _Unwind_Reason_Code
 295     _Unwind_Resume_or_Rethrow(_Unwind_Exception *exception_object);
 296 #endif
 297
 298 // _Unwind_Backtrace() is a gcc extension that walks the stack and calls the
 299 // _Unwind_Trace_Fn once per frame until it reaches the bottom of the stack
 300 // or the _Unwind_Trace_Fn function returns something other than _URC_NO_REASON.
 301 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)(struct _Unwind_Context *,
 302                                                 void *);
 303 extern _Unwind_Reason_Code _Unwind_Backtrace(_Unwind_Trace_Fn, void *);
 304
 305 // _Unwind_GetCFA is a gcc extension that can be called from within a
 306 // personality handler to get the CFA (stack pointer before call) of
 307 // current frame.
 308 extern uintptr_t _Unwind_GetCFA(struct _Unwind_Context *);
 309
 310
 311 // _Unwind_GetIPInfo is a gcc extension that can be called from within a
 312 // personality handler.  Similar to _Unwind_GetIP() but also returns in
 313 // *ipBefore a non-zero value if the instruction pointer is at or before the
 314 // instruction causing the unwind. Normally, in a function call, the IP returned
 315 // is the return address which is after the call instruction and may be past the
 316 // end of the function containing the call instruction.
 317 extern uintptr_t _Unwind_GetIPInfo(struct _Unwind_Context *context,
 318                                    int *ipBefore);
 319
 320
 321 // __register_frame() is used with dynamically generated code to register the
 322 // FDE for a generated (JIT) code.  The FDE must use pc-rel addressing to point
 323 // to its function and optional LSDA.
 324 // __register_frame() has existed in all versions of Mac OS X, but in 10.4 and
 325 // 10.5 it was buggy and did not actually register the FDE with the unwinder.
 326 // In 10.6 and later it does register properly.
 327 extern void __register_frame(const void *fde);
 328 extern void __deregister_frame(const void *fde);
 329
 330 // _Unwind_Find_FDE() will locate the FDE if the pc is in some function that has
 331 // an associated FDE. Note, Mac OS X 10.6 and later, introduces "compact unwind
 332 // info" which the runtime uses in preference to DWARF unwind info.  This
 333 // function will only work if the target function has an FDE but no compact
 334 // unwind info.
 335 struct dwarf_eh_bases {
 336   uintptr_t tbase;
 337   uintptr_t dbase;
 338   uintptr_t func;
 339 };
 340 extern const void *_Unwind_Find_FDE(const void *pc, struct dwarf_eh_bases *);
 341
 342
 343 // This function attempts to find the start (address of first instruction) of
 344 // a function given an address inside the function.  It only works if the
 345 // function has an FDE (DWARF unwind info).
 346 // This function is unimplemented on Mac OS X 10.6 and later.  Instead, use
 347 // _Unwind_Find_FDE() and look at the dwarf_eh_bases.func result.
 348 extern void *_Unwind_FindEnclosingFunction(void *pc);
 349
 350 // Mac OS X does not support text-rel and data-rel addressing so these functions
 351 // are unimplemented
 352 extern uintptr_t _Unwind_GetDataRelBase(struct _Unwind_Context *context)
 353     LIBUNWIND_UNAVAIL;
 354 extern uintptr_t _Unwind_GetTextRelBase(struct _Unwind_Context *context)
 355     LIBUNWIND_UNAVAIL;
 356
 357 // Mac OS X 10.4 and 10.5 had implementations of these functions in
 358 // libgcc_s.dylib, but they never worked.
 359 /// These functions are no longer available on Mac OS X.
 360 extern void __register_frame_info_bases(const void *fde, void *ob, void *tb,
 361                                         void *db) LIBUNWIND_UNAVAIL;
 362 extern void __register_frame_info(const void *fde, void *ob)
 363     LIBUNWIND_UNAVAIL;
 364 extern void __register_frame_info_table_bases(const void *fde, void *ob,
 365                                               void *tb, void *db)
 366     LIBUNWIND_UNAVAIL;
 367 extern void __register_frame_info_table(const void *fde, void *ob)
 368     LIBUNWIND_UNAVAIL;
 369 extern void __register_frame_table(const void *fde)
 370     LIBUNWIND_UNAVAIL;
 371 extern void *__deregister_frame_info(const void *fde)
 372     LIBUNWIND_UNAVAIL;
 373 extern void *__deregister_frame_info_bases(const void *fde)
 374     LIBUNWIND_UNAVAIL;
 375
 376 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
 377 #ifndef _WIN32
 378 typedef struct _EXCEPTION_RECORD EXCEPTION_RECORD;
 379 typedef struct _CONTEXT CONTEXT;
 380 typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
 381 #elif !defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
 382 typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
 383 #endif
 384 // This is the common wrapper for GCC-style personality functions with SEH.
 385 extern EXCEPTION_DISPOSITION _GCC_specific_handler(EXCEPTION_RECORD *exc,
 386                                                    void *frame, CONTEXT *ctx,
 387                                                    DISPATCHER_CONTEXT *disp,
 388                                                    _Unwind_Personality_Fn pers);
 389 #endif
 390
 391 #ifdef __cplusplus
 392 }
 393 #endif
 394
 395 #endif // __UNWIND_H__