text: //===------------------------------- unwind.h -----------------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //
  // C++ ABI Level 1 ABI documented at:
  //   https://itanium-cxx-abi.github.io/cxx-abi/abi-eh.html
  //
  //===----------------------------------------------------------------------===//
  
  #ifndef __UNWIND_H__
  #define __UNWIND_H__
  
  #include "__libunwind_config.h"
  
  #include <stdint.h>
  #include <stddef.h>
  
  #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__) && defined(_WIN32)
  #include <windows.h>
  #include <ntverp.h>
  #endif
  
  #if defined(__APPLE__)
  #define LIBUNWIND_UNAVAIL __attribute__ (( deprecated ))
  #else
  #define LIBUNWIND_UNAVAIL
  #endif
  
  typedef enum {
    _URC_NO_REASON = 0,
    _URC_OK = 0,
    _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
    _URC_FATAL_PHASE2_ERROR = 2,
    _URC_FATAL_PHASE1_ERROR = 3,
    _URC_NORMAL_STOP = 4,
    _URC_END_OF_STACK = 5,
    _URC_HANDLER_FOUND = 6,
    _URC_INSTALL_CONTEXT = 7,
    _URC_CONTINUE_UNWIND = 8,
  #if defined(_LIBUNWIND_ARM_EHABI)
    _URC_FAILURE = 9
  #endif
  } _Unwind_Reason_Code;
  
  typedef enum {
    _UA_SEARCH_PHASE = 1,
    _UA_CLEANUP_PHASE = 2,
    _UA_HANDLER_FRAME = 4,
    _UA_FORCE_UNWIND = 8,
    _UA_END_OF_STACK = 16 // gcc extension to C++ ABI
  } _Unwind_Action;
  
  typedef struct _Unwind_Context _Unwind_Context;   // opaque
  
  #if defined(_LIBUNWIND_ARM_EHABI)
  typedef uint32_t _Unwind_State;
  
  static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME   = 0;
  static const _Unwind_State _US_UNWIND_FRAME_STARTING  = 1;
  static const _Unwind_State _US_UNWIND_FRAME_RESUME    = 2;
  static const _Unwind_State _US_ACTION_MASK            = 3;
  /* Undocumented flag for force unwinding. */
  static const _Unwind_State _US_FORCE_UNWIND           = 8;
  
  typedef uint32_t _Unwind_EHT_Header;
  
  struct _Unwind_Control_Block;
  typedef struct _Unwind_Control_Block _Unwind_Control_Block;
  typedef struct _Unwind_Control_Block _Unwind_Exception; /* Alias */
  
  struct _Unwind_Control_Block {
    uint64_t exception_class;
    void (*exception_cleanup)(_Unwind_Reason_Code, _Unwind_Control_Block*);
  
    /* Unwinder cache, private fields for the unwinder's use */
    struct {
      uint32_t reserved1; /* init reserved1 to 0, then don't touch */
      uint32_t reserved2;
      uint32_t reserved3;
      uint32_t reserved4;
      uint32_t reserved5;
    } unwinder_cache;
  
    /* Propagation barrier cache (valid after phase 1): */
    struct {
      uint32_t sp;
      uint32_t bitpattern[5];
    } barrier_cache;
  
    /* Cleanup cache (preserved over cleanup): */
    struct {
      uint32_t bitpattern[4];
    } cleanup_cache;
  
    /* Pr cache (for pr's benefit): */
    struct {
      uint32_t fnstart; /* function start address */
      _Unwind_EHT_Header* ehtp; /* pointer to EHT entry header word */
      uint32_t additional;
      uint32_t reserved1;
    } pr_cache;
  
    long long int :0; /* Enforce the 8-byte alignment */
  #ifndef _MSC_VER
  } __attribute__((__aligned__(8)));
  #else
  } __declspec(align(8));
  #endif
  
  typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
        (_Unwind_State state,
         _Unwind_Exception* exceptionObject,
         struct _Unwind_Context* context);
  
  typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)(
      _Unwind_State state, _Unwind_Exception *exceptionObject,
      struct _Unwind_Context *context);
  #else
  struct _Unwind_Context;   // opaque
  struct _Unwind_Exception; // forward declaration
  typedef struct _Unwind_Exception _Unwind_Exception;
  
  struct _Unwind_Exception {
    uint64_t exception_class;
    void (*exception_cleanup)(_Unwind_Reason_Code reason,
                              _Unwind_Exception *exc);
  #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
    uintptr_t private_[6];
  #else
    uintptr_t private_1; // non-zero means forced unwind
    uintptr_t private_2; // holds sp that phase1 found for phase2 to use
  #endif
  #if __SIZEOF_POINTER__ == 4
    // The implementation of _Unwind_Exception uses an attribute mode on the
    // above fields which has the side effect of causing this whole struct to
    // round up to 32 bytes in size (48 with SEH). To be more explicit, we add
    // pad fields added for binary compatibility.
    uint32_t reserved[3];
  #endif
    // The Itanium ABI requires that _Unwind_Exception objects are "double-word
    // aligned".  GCC has interpreted this to mean "use the maximum useful
    // alignment for the target"; so do we.
  #ifndef _MSC_VER
  } __attribute__((__aligned__));
  #else
  } __declspec(align(8));
  #endif
  
  typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
      (int version,
       _Unwind_Action actions,
       uint64_t exceptionClass,
       _Unwind_Exception* exceptionObject,
       struct _Unwind_Context* context,
       void* stop_parameter );
  
  typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)(
      int version, _Unwind_Action actions, uint64_t exceptionClass,
      _Unwind_Exception *exceptionObject, struct _Unwind_Context *context);
  #endif
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  //
  // The following are the base functions documented by the C++ ABI
  //
  #ifdef __USING_SJLJ_EXCEPTIONS__
  extern _Unwind_Reason_Code
      _Unwind_SjLj_RaiseException(_Unwind_Exception *exception_object);
  extern void _Unwind_SjLj_Resume(_Unwind_Exception *exception_object);
  #else
  extern _Unwind_Reason_Code
      _Unwind_RaiseException(_Unwind_Exception *exception_object);
  extern void _Unwind_Resume(_Unwind_Exception *exception_object);
  #endif
  extern void _Unwind_DeleteException(_Unwind_Exception *exception_object);
  
  #if defined(_LIBUNWIND_ARM_EHABI)
  typedef enum {
    _UVRSC_CORE = 0, /* integer register */
    _UVRSC_VFP = 1, /* vfp */
    _UVRSC_WMMXD = 3, /* Intel WMMX data register */
    _UVRSC_WMMXC = 4 /* Intel WMMX control register */
  } _Unwind_VRS_RegClass;
  
  typedef enum {
    _UVRSD_UINT32 = 0,
    _UVRSD_VFPX = 1,
    _UVRSD_UINT64 = 3,
    _UVRSD_FLOAT = 4,
    _UVRSD_DOUBLE = 5
  } _Unwind_VRS_DataRepresentation;
  
  typedef enum {
    _UVRSR_OK = 0,
    _UVRSR_NOT_IMPLEMENTED = 1,
    _UVRSR_FAILED = 2
  } _Unwind_VRS_Result;
  
  extern void _Unwind_Complete(_Unwind_Exception* exception_object);
  
  extern _Unwind_VRS_Result
  _Unwind_VRS_Get(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
                  uint32_t regno, _Unwind_VRS_DataRepresentation representation,
                  void *valuep);
  
  extern _Unwind_VRS_Result
  _Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
                  uint32_t regno, _Unwind_VRS_DataRepresentation representation,
                  void *valuep);
  
  extern _Unwind_VRS_Result
  _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
                  uint32_t discriminator,
                  _Unwind_VRS_DataRepresentation representation);
  #endif
  
  #if !defined(_LIBUNWIND_ARM_EHABI)
  
  extern uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index);
  extern void _Unwind_SetGR(struct _Unwind_Context *context, int index,
                            uintptr_t new_value);
  extern uintptr_t _Unwind_GetIP(struct _Unwind_Context *context);
  extern void _Unwind_SetIP(struct _Unwind_Context *, uintptr_t new_value);
  
  #else  // defined(_LIBUNWIND_ARM_EHABI)
  
  #if defined(_LIBUNWIND_UNWIND_LEVEL1_EXTERNAL_LINKAGE)
  #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 extern
  #else
  #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 static __inline__
  #endif
  
  // These are de facto helper functions for ARM, which delegate the function
  // calls to _Unwind_VRS_Get/Set().  These are not a part of ARM EHABI
  // specification, thus these function MUST be inlined.  Please don't replace
  // these with the "extern" function declaration; otherwise, the program
  // including this <unwind.h> header won't be ABI compatible and will result in
  // link error when we are linking the program with libgcc.
  
  _LIBUNWIND_EXPORT_UNWIND_LEVEL1
  uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index) {
    uintptr_t value = 0;
    _Unwind_VRS_Get(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
    return value;
  }
  
  _LIBUNWIND_EXPORT_UNWIND_LEVEL1
  void _Unwind_SetGR(struct _Unwind_Context *context, int index,
                     uintptr_t value) {
    _Unwind_VRS_Set(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
  }
  
  _LIBUNWIND_EXPORT_UNWIND_LEVEL1
  uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) {
    // remove the thumb-bit before returning
    return _Unwind_GetGR(context, 15) & (~(uintptr_t)0x1);
  }
  
  _LIBUNWIND_EXPORT_UNWIND_LEVEL1
  void _Unwind_SetIP(struct _Unwind_Context *context, uintptr_t value) {
    uintptr_t thumb_bit = _Unwind_GetGR(context, 15) & ((uintptr_t)0x1);
    _Unwind_SetGR(context, 15, value | thumb_bit);
  }
  #endif  // defined(_LIBUNWIND_ARM_EHABI)
  
  extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context);
  extern uintptr_t
      _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context);
  #ifdef __USING_SJLJ_EXCEPTIONS__
  extern _Unwind_Reason_Code
      _Unwind_SjLj_ForcedUnwind(_Unwind_Exception *exception_object,
                                _Unwind_Stop_Fn stop, void *stop_parameter);
  #else
  extern _Unwind_Reason_Code
      _Unwind_ForcedUnwind(_Unwind_Exception *exception_object,
                           _Unwind_Stop_Fn stop, void *stop_parameter);
  #endif
  
  #ifdef __USING_SJLJ_EXCEPTIONS__
  typedef struct _Unwind_FunctionContext *_Unwind_FunctionContext_t;
  extern void _Unwind_SjLj_Register(_Unwind_FunctionContext_t fc);
  extern void _Unwind_SjLj_Unregister(_Unwind_FunctionContext_t fc);
  #endif
  
  //
  // The following are semi-suppoted extensions to the C++ ABI
  //
  
  //
  //  called by __cxa_rethrow().
  //
  #ifdef __USING_SJLJ_EXCEPTIONS__
  extern _Unwind_Reason_Code
      _Unwind_SjLj_Resume_or_Rethrow(_Unwind_Exception *exception_object);
  #else
  extern _Unwind_Reason_Code
      _Unwind_Resume_or_Rethrow(_Unwind_Exception *exception_object);
  #endif
  
  // _Unwind_Backtrace() is a gcc extension that walks the stack and calls the
  // _Unwind_Trace_Fn once per frame until it reaches the bottom of the stack
  // or the _Unwind_Trace_Fn function returns something other than _URC_NO_REASON.
  typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)(struct _Unwind_Context *,
                                                  void *);
  extern _Unwind_Reason_Code _Unwind_Backtrace(_Unwind_Trace_Fn, void *);
  
  // _Unwind_GetCFA is a gcc extension that can be called from within a
  // personality handler to get the CFA (stack pointer before call) of
  // current frame.
  extern uintptr_t _Unwind_GetCFA(struct _Unwind_Context *);
  
  
  // _Unwind_GetIPInfo is a gcc extension that can be called from within a
  // personality handler.  Similar to _Unwind_GetIP() but also returns in
  // *ipBefore a non-zero value if the instruction pointer is at or before the
  // instruction causing the unwind. Normally, in a function call, the IP returned
  // is the return address which is after the call instruction and may be past the
  // end of the function containing the call instruction.
  extern uintptr_t _Unwind_GetIPInfo(struct _Unwind_Context *context,
                                     int *ipBefore);
  
  
  // __register_frame() is used with dynamically generated code to register the
  // FDE for a generated (JIT) code.  The FDE must use pc-rel addressing to point
  // to its function and optional LSDA.
  // __register_frame() has existed in all versions of Mac OS X, but in 10.4 and
  // 10.5 it was buggy and did not actually register the FDE with the unwinder.
  // In 10.6 and later it does register properly.
  extern void __register_frame(const void *fde);
  extern void __deregister_frame(const void *fde);
  
  // _Unwind_Find_FDE() will locate the FDE if the pc is in some function that has
  // an associated FDE. Note, Mac OS X 10.6 and later, introduces "compact unwind
  // info" which the runtime uses in preference to DWARF unwind info.  This
  // function will only work if the target function has an FDE but no compact
  // unwind info.
  struct dwarf_eh_bases {
    uintptr_t tbase;
    uintptr_t dbase;
    uintptr_t func;
  };
  extern const void *_Unwind_Find_FDE(const void *pc, struct dwarf_eh_bases *);
  
  
  // This function attempts to find the start (address of first instruction) of
  // a function given an address inside the function.  It only works if the
  // function has an FDE (DWARF unwind info).
  // This function is unimplemented on Mac OS X 10.6 and later.  Instead, use
  // _Unwind_Find_FDE() and look at the dwarf_eh_bases.func result.
  extern void *_Unwind_FindEnclosingFunction(void *pc);
  
  // Mac OS X does not support text-rel and data-rel addressing so these functions
  // are unimplemented
  extern uintptr_t _Unwind_GetDataRelBase(struct _Unwind_Context *context)
      LIBUNWIND_UNAVAIL;
  extern uintptr_t _Unwind_GetTextRelBase(struct _Unwind_Context *context)
      LIBUNWIND_UNAVAIL;
  
  // Mac OS X 10.4 and 10.5 had implementations of these functions in
  // libgcc_s.dylib, but they never worked.
  /// These functions are no longer available on Mac OS X.
  extern void __register_frame_info_bases(const void *fde, void *ob, void *tb,
                                          void *db) LIBUNWIND_UNAVAIL;
  extern void __register_frame_info(const void *fde, void *ob)
      LIBUNWIND_UNAVAIL;
  extern void __register_frame_info_table_bases(const void *fde, void *ob,
                                                void *tb, void *db)
      LIBUNWIND_UNAVAIL;
  extern void __register_frame_info_table(const void *fde, void *ob)
      LIBUNWIND_UNAVAIL;
  extern void __register_frame_table(const void *fde)
      LIBUNWIND_UNAVAIL;
  extern void *__deregister_frame_info(const void *fde)
      LIBUNWIND_UNAVAIL;
  extern void *__deregister_frame_info_bases(const void *fde)
      LIBUNWIND_UNAVAIL;
  
  #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
  #ifndef _WIN32
  typedef struct _EXCEPTION_RECORD EXCEPTION_RECORD;
  typedef struct _CONTEXT CONTEXT;
  typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
  #elif !defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
  typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
  #endif
  // This is the common wrapper for GCC-style personality functions with SEH.
  extern EXCEPTION_DISPOSITION _GCC_specific_handler(EXCEPTION_RECORD *exc,
                                                     void *frame, CONTEXT *ctx,
                                                     DISPATCHER_CONTEXT *disp,
                                                     _Unwind_Personality_Fn pers);
  #endif
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif // __UNWIND_H__
  