Unwind Data Definitions in C

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The following is a C description of the unwind data:

typedef enum _UNWIND_OP_CODES {  
    UWOP_PUSH_NONVOL = 0, /* info == register number */  
    UWOP_ALLOC_LARGE,     /* no info, alloc size in next 2 slots */  
    UWOP_ALLOC_SMALL,     /* info == size of allocation / 8 - 1 */  
    UWOP_SET_FPREG,       /* no info, FP = RSP + UNWIND_INFO.FPRegOffset*16 */  
    UWOP_SAVE_NONVOL,     /* info == register number, offset in next slot */  
    UWOP_SAVE_NONVOL_FAR, /* info == register number, offset in next 2 slots */  
    UWOP_SAVE_XMM128,     /* info == XMM reg number, offset in next slot */  
    UWOP_SAVE_XMM128_FAR, /* info == XMM reg number, offset in next 2 slots */  
    UWOP_PUSH_MACHFRAME   /* info == 0: no error-code, 1: error-code */  
} UNWIND_CODE_OPS;  
  
typedef union _UNWIND_CODE {  
    struct {  
        UBYTE CodeOffset;  
        UBYTE UnwindOp : 4;  
        UBYTE OpInfo   : 4;  
    };  
    USHORT FrameOffset;  
} UNWIND_CODE, *PUNWIND_CODE;  
  
#define UNW_FLAG_EHANDLER  0x01  
#define UNW_FLAG_UHANDLER  0x02  
#define UNW_FLAG_CHAININFO 0x04  
  
typedef struct _UNWIND_INFO {  
    UBYTE Version       : 3;  
    UBYTE Flags         : 5;  
    UBYTE SizeOfProlog;  
    UBYTE CountOfCodes;  
    UBYTE FrameRegister : 4;  
    UBYTE FrameOffset   : 4;  
    UNWIND_CODE UnwindCode[1];  
/*  UNWIND_CODE MoreUnwindCode[((CountOfCodes + 1) & ~1) - 1];  
*   union {  
*       OPTIONAL ULONG ExceptionHandler;  
*       OPTIONAL ULONG FunctionEntry;  
*   };  
*   OPTIONAL ULONG ExceptionData[]; */  
} UNWIND_INFO, *PUNWIND_INFO;  
  
typedef struct _RUNTIME_FUNCTION {  
    ULONG BeginAddress;  
    ULONG EndAddress;  
    ULONG UnwindData;  
} RUNTIME_FUNCTION, *PRUNTIME_FUNCTION;  
  
#define GetUnwindCodeEntry(info, index) \  
    ((info)->UnwindCode[index])  
  
#define GetLanguageSpecificDataPtr(info) \  
    ((PVOID)&GetUnwindCodeEntry((info),((info)->CountOfCodes + 1) & ~1))  
  
#define GetExceptionHandler(base, info) \  
    ((PEXCEPTION_HANDLER)((base) + *(PULONG)GetLanguageSpecificDataPtr(info)))  
  
#define GetChainedFunctionEntry(base, info) \  
    ((PRUNTIME_FUNCTION)((base) + *(PULONG)GetLanguageSpecificDataPtr(info)))  
  
#define GetExceptionDataPtr(info) \  
    ((PVOID)((PULONG)GetLanguageSpecificData(info) + 1)  

See Also

Exception Handling (x64)