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 (*__personality_routine)
 115       (_Unwind_State state,
 116        _Unwind_Exception* exceptionObject,
 117        struct _Unwind_Context* context);
 118 #else
 119 struct _Unwind_Context;   // opaque
 120 struct _Unwind_Exception; // forward declaration
 121 typedef struct _Unwind_Exception _Unwind_Exception;
 122
 123 struct _Unwind_Exception {
 124   uint64_t exception_class;
 125   void (*exception_cleanup)(_Unwind_Reason_Code reason,
 126                             _Unwind_Exception *exc);
 127 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
 128   uintptr_t private_[6];
 129 #else
 130   uintptr_t private_1; // non-zero means forced unwind
 131   uintptr_t private_2; // holds sp that phase1 found for phase2 to use
 132 #endif
 133 #if __SIZEOF_POINTER__ == 4
 134   // The implementation of _Unwind_Exception uses an attribute mode on the
 135   // above fields which has the side effect of causing this whole struct to
 136   // round up to 32 bytes in size (48 with SEH). To be more explicit, we add
 137   // pad fields added for binary compatibility.
 138   uint32_t reserved[3];
 139 #endif
 140   // The Itanium ABI requires that _Unwind_Exception objects are "double-word
 141   // aligned".  GCC has interpreted this to mean "use the maximum useful
 142   // alignment for the target"; so do we.
 143 } __attribute__((__aligned__));
 144
 145 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
 146     (int version,
 147      _Unwind_Action actions,
 148      uint64_t exceptionClass,
 149      _Unwind_Exception* exceptionObject,
 150      struct _Unwind_Context* context,
 151      void* stop_parameter );
 152
 153 typedef _Unwind_Reason_Code (*__personality_routine)
 154       (int version,
 155        _Unwind_Action actions,
 156        uint64_t exceptionClass,
 157        _Unwind_Exception* exceptionObject,
 158        struct _Unwind_Context* context);
 159 #endif
 160
 161 #ifdef __cplusplus
 162 extern "C" {
 163 #endif
 164
 165 //
 166 // The following are the base functions documented by the C++ ABI
 167 //
 168 #ifdef __USING_SJLJ_EXCEPTIONS__
 169 extern _Unwind_Reason_Code
 170     _Unwind_SjLj_RaiseException(_Unwind_Exception *exception_object);
 171 extern void _Unwind_SjLj_Resume(_Unwind_Exception *exception_object);
 172 #else
 173 extern _Unwind_Reason_Code
 174     _Unwind_RaiseException(_Unwind_Exception *exception_object);
 175 extern void _Unwind_Resume(_Unwind_Exception *exception_object);
 176 #endif
 177 extern void _Unwind_DeleteException(_Unwind_Exception *exception_object);
 178
 179 #if defined(_LIBUNWIND_ARM_EHABI)
 180 typedef enum {
 181   _UVRSC_CORE = 0, /* integer register */
 182   _UVRSC_VFP = 1, /* vfp */
 183   _UVRSC_WMMXD = 3, /* Intel WMMX data register */
 184   _UVRSC_WMMXC = 4 /* Intel WMMX control register */
 185 } _Unwind_VRS_RegClass;
 186
 187 typedef enum {
 188   _UVRSD_UINT32 = 0,
 189   _UVRSD_VFPX = 1,
 190   _UVRSD_UINT64 = 3,
 191   _UVRSD_FLOAT = 4,
 192   _UVRSD_DOUBLE = 5
 193 } _Unwind_VRS_DataRepresentation;
 194
 195 typedef enum {
 196   _UVRSR_OK = 0,
 197   _UVRSR_NOT_IMPLEMENTED = 1,
 198   _UVRSR_FAILED = 2
 199 } _Unwind_VRS_Result;
 200
 201 extern void _Unwind_Complete(_Unwind_Exception* exception_object);
 202
 203 extern _Unwind_VRS_Result
 204 _Unwind_VRS_Get(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
 205                 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
 206                 void *valuep);
 207
 208 extern _Unwind_VRS_Result
 209 _Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
 210                 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
 211                 void *valuep);
 212
 213 extern _Unwind_VRS_Result
 214 _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
 215                 uint32_t discriminator,
 216                 _Unwind_VRS_DataRepresentation representation);
 217 #endif
 218
 219 #if !defined(_LIBUNWIND_ARM_EHABI)
 220
 221 extern uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index);
 222 extern void _Unwind_SetGR(struct _Unwind_Context *context, int index,
 223                           uintptr_t new_value);
 224 extern uintptr_t _Unwind_GetIP(struct _Unwind_Context *context);
 225 extern void _Unwind_SetIP(struct _Unwind_Context *, uintptr_t new_value);
 226
 227 #else  // defined(_LIBUNWIND_ARM_EHABI)
 228
 229 #if defined(_LIBUNWIND_UNWIND_LEVEL1_EXTERNAL_LINKAGE)
 230 #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 extern
 231 #else
 232 #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 static __inline__
 233 #endif
 234
 235 // These are de facto helper functions for ARM, which delegate the function
 236 // calls to _Unwind_VRS_Get/Set().  These are not a part of ARM EHABI
 237 // specification, thus these function MUST be inlined.  Please don't replace
 238 // these with the "extern" function declaration; otherwise, the program
 239 // including this <unwind.h> header won't be ABI compatible and will result in
 240 // link error when we are linking the program with libgcc.
 241
 242 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 243 uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index) {
 244   uintptr_t value = 0;
 245   _Unwind_VRS_Get(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
 246   return value;
 247 }
 248
 249 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 250 void _Unwind_SetGR(struct _Unwind_Context *context, int index,
 251                    uintptr_t value) {
 252   _Unwind_VRS_Set(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
 253 }
 254
 255 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 256 uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) {
 257   // remove the thumb-bit before returning
 258   return _Unwind_GetGR(context, 15) & (~(uintptr_t)0x1);
 259 }
 260
 261 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
 262 void _Unwind_SetIP(struct _Unwind_Context *context, uintptr_t value) {
 263   uintptr_t thumb_bit = _Unwind_GetGR(context, 15) & ((uintptr_t)0x1);
 264   _Unwind_SetGR(context, 15, value | thumb_bit);
 265 }
 266 #endif  // defined(_LIBUNWIND_ARM_EHABI)
 267
 268 extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context);
 269 extern uintptr_t
 270     _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context);
 271 #ifdef __USING_SJLJ_EXCEPTIONS__
 272 extern _Unwind_Reason_Code
 273     _Unwind_SjLj_ForcedUnwind(_Unwind_Exception *exception_object,
 274                               _Unwind_Stop_Fn stop, void *stop_parameter);
 275 #else
 276 extern _Unwind_Reason_Code
 277     _Unwind_ForcedUnwind(_Unwind_Exception *exception_object,
 278                          _Unwind_Stop_Fn stop, void *stop_parameter);
 279 #endif
 280
 281 #ifdef __USING_SJLJ_EXCEPTIONS__
 282 typedef struct _Unwind_FunctionContext *_Unwind_FunctionContext_t;
 283 extern void _Unwind_SjLj_Register(_Unwind_FunctionContext_t fc);
 284 extern void _Unwind_SjLj_Unregister(_Unwind_FunctionContext_t fc);
 285 #endif
 286
 287 //
 288 // The following are semi-suppoted extensions to the C++ ABI
 289 //
 290
 291 //
 292 //  called by __cxa_rethrow().
 293 //
 294 #ifdef __USING_SJLJ_EXCEPTIONS__
 295 extern _Unwind_Reason_Code
 296     _Unwind_SjLj_Resume_or_Rethrow(_Unwind_Exception *exception_object);
 297 #else
 298 extern _Unwind_Reason_Code
 299     _Unwind_Resume_or_Rethrow(_Unwind_Exception *exception_object);
 300 #endif
 301
 302 // _Unwind_Backtrace() is a gcc extension that walks the stack and calls the
 303 // _Unwind_Trace_Fn once per frame until it reaches the bottom of the stack
 304 // or the _Unwind_Trace_Fn function returns something other than _URC_NO_REASON.
 305 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)(struct _Unwind_Context *,
 306                                                 void *);
 307 extern _Unwind_Reason_Code _Unwind_Backtrace(_Unwind_Trace_Fn, void *);
 308
 309 // _Unwind_GetCFA is a gcc extension that can be called from within a
 310 // personality handler to get the CFA (stack pointer before call) of
 311 // current frame.
 312 extern uintptr_t _Unwind_GetCFA(struct _Unwind_Context *);
 313
 314
 315 // _Unwind_GetIPInfo is a gcc extension that can be called from within a
 316 // personality handler.  Similar to _Unwind_GetIP() but also returns in
 317 // *ipBefore a non-zero value if the instruction pointer is at or before the
 318 // instruction causing the unwind. Normally, in a function call, the IP returned
 319 // is the return address which is after the call instruction and may be past the
 320 // end of the function containing the call instruction.
 321 extern uintptr_t _Unwind_GetIPInfo(struct _Unwind_Context *context,
 322                                    int *ipBefore);
 323
 324
 325 // __register_frame() is used with dynamically generated code to register the
 326 // FDE for a generated (JIT) code.  The FDE must use pc-rel addressing to point
 327 // to its function and optional LSDA.
 328 // __register_frame() has existed in all versions of Mac OS X, but in 10.4 and
 329 // 10.5 it was buggy and did not actually register the FDE with the unwinder.
 330 // In 10.6 and later it does register properly.
 331 extern void __register_frame(const void *fde);
 332 extern void __deregister_frame(const void *fde);
 333
 334 // _Unwind_Find_FDE() will locate the FDE if the pc is in some function that has
 335 // an associated FDE. Note, Mac OS X 10.6 and later, introduces "compact unwind
 336 // info" which the runtime uses in preference to DWARF unwind info.  This
 337 // function will only work if the target function has an FDE but no compact
 338 // unwind info.
 339 struct dwarf_eh_bases {
 340   uintptr_t tbase;
 341   uintptr_t dbase;
 342   uintptr_t func;
 343 };
 344 extern const void *_Unwind_Find_FDE(const void *pc, struct dwarf_eh_bases *);
 345
 346
 347 // This function attempts to find the start (address of first instruction) of
 348 // a function given an address inside the function.  It only works if the
 349 // function has an FDE (DWARF unwind info).
 350 // This function is unimplemented on Mac OS X 10.6 and later.  Instead, use
 351 // _Unwind_Find_FDE() and look at the dwarf_eh_bases.func result.
 352 extern void *_Unwind_FindEnclosingFunction(void *pc);
 353
 354 // Mac OS X does not support text-rel and data-rel addressing so these functions
 355 // are unimplemented
 356 extern uintptr_t _Unwind_GetDataRelBase(struct _Unwind_Context *context)
 357     LIBUNWIND_UNAVAIL;
 358 extern uintptr_t _Unwind_GetTextRelBase(struct _Unwind_Context *context)
 359     LIBUNWIND_UNAVAIL;
 360
 361 // Mac OS X 10.4 and 10.5 had implementations of these functions in
 362 // libgcc_s.dylib, but they never worked.
 363 /// These functions are no longer available on Mac OS X.
 364 extern void __register_frame_info_bases(const void *fde, void *ob, void *tb,
 365                                         void *db) LIBUNWIND_UNAVAIL;
 366 extern void __register_frame_info(const void *fde, void *ob)
 367     LIBUNWIND_UNAVAIL;
 368 extern void __register_frame_info_table_bases(const void *fde, void *ob,
 369                                               void *tb, void *db)
 370     LIBUNWIND_UNAVAIL;
 371 extern void __register_frame_info_table(const void *fde, void *ob)
 372     LIBUNWIND_UNAVAIL;
 373 extern void __register_frame_table(const void *fde)
 374     LIBUNWIND_UNAVAIL;
 375 extern void *__deregister_frame_info(const void *fde)
 376     LIBUNWIND_UNAVAIL;
 377 extern void *__deregister_frame_info_bases(const void *fde)
 378     LIBUNWIND_UNAVAIL;
 379
 380 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
 381 #ifndef _WIN32
 382 typedef struct _EXCEPTION_RECORD EXCEPTION_RECORD;
 383 typedef struct _CONTEXT CONTEXT;
 384 typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
 385 #elif !defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
 386 typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
 387 #endif
 388 // This is the common wrapper for GCC-style personality functions with SEH.
 389 extern EXCEPTION_DISPOSITION _GCC_specific_handler(EXCEPTION_RECORD *exc,
 390                                                    void *frame,
 391                                                    CONTEXT *ctx,
 392                                                    DISPATCHER_CONTEXT *disp,
 393                                                    __personality_routine pers);
 394 #endif
 395
 396 #ifdef __cplusplus
 397 }
 398 #endif
 399
 400 #endif // __UNWIND_H__