unwind.h

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/*===---- unwind.h - Stack unwinding ----------------------------------------===
 *
 * 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
 *
 *===-----------------------------------------------------------------------===
 */

/* See "Data Definitions for libgcc_s" in the Linux Standard Base.*/

#ifndef __CLANG_UNWIND_H
#define __CLANG_UNWIND_H

#if defined(__APPLE__) && __has_include_next(<unwind.h>)
/* Darwin (from 11.x on) provide an unwind.h. If that's available,
 * use it. libunwind wraps some of its definitions in #ifdef _GNU_SOURCE,
 * so define that around the include.*/
# ifndef _GNU_SOURCE
#  define _SHOULD_UNDEFINE_GNU_SOURCE
#  define _GNU_SOURCE
# endif
// libunwind's unwind.h reflects the current visibility.  However, Mozilla
// builds with -fvisibility=hidden and relies on gcc's unwind.h to reset the
// visibility to default and export its contents.  gcc also allows users to
// override its override by #defining HIDE_EXPORTS (but note, this only obeys
// the user's -fvisibility setting; it doesn't hide any exports on its own).  We
// imitate gcc's header here:
# ifdef HIDE_EXPORTS
#  include_next <unwind.h>
# else
#  pragma GCC visibility push(default)
#  include_next <unwind.h>
#  pragma GCC visibility pop
# endif
# ifdef _SHOULD_UNDEFINE_GNU_SOURCE
#  undef _GNU_SOURCE
#  undef _SHOULD_UNDEFINE_GNU_SOURCE
# endif
#else

#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

/* It is a bit strange for a header to play with the visibility of the
   symbols it declares, but this matches gcc's behavior and some programs
   depend on it */
#ifndef HIDE_EXPORTS
#pragma GCC visibility push(default)
#endif

typedef uintptr_t _Unwind_Word __attribute__((__mode__(__unwind_word__)));
typedef intptr_t _Unwind_Sword __attribute__((__mode__(__unwind_word__)));
typedef uintptr_t _Unwind_Ptr;
typedef uintptr_t _Unwind_Internal_Ptr;
typedef uint64_t _Unwind_Exception_Class;

typedef intptr_t _sleb128_t;
typedef uintptr_t _uleb128_t;

struct _Unwind_Context;
#if defined(__arm__) && !(defined(__USING_SJLJ_EXCEPTIONS__) || defined(__ARM_DWARF_EH__))
struct _Unwind_Control_Block;
typedef struct _Unwind_Control_Block _Unwind_Exception; /* Alias */
#else
struct _Unwind_Exception;
typedef struct _Unwind_Exception _Unwind_Exception;
#endif
typedef enum {
  _URC_NO_REASON = 0,
#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && \
    !defined(__ARM_DWARF_EH__)
  _URC_OK = 0, /* used by ARM EHABI */
#endif
  _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(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && \
    !defined(__ARM_DWARF_EH__)
  _URC_FAILURE = 9 /* used by ARM EHABI */
#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 void (*_Unwind_Exception_Cleanup_Fn)(_Unwind_Reason_Code,
                                             _Unwind_Exception *);

#if defined(__arm__) && !(defined(__USING_SJLJ_EXCEPTIONS__) || defined(__ARM_DWARF_EH__))
typedef struct _Unwind_Control_Block _Unwind_Control_Block;
typedef uint32_t _Unwind_EHT_Header;

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; /* forced unwind stop function, 0 if not forced */
    uint32_t reserved2; /* personality routine */
    uint32_t reserved3; /* callsite */
    uint32_t reserved4; /* forced unwind stop argument */
    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;
  /* personality cache (for personality's benefit) */
  struct {
    uint32_t fnstart;         /* function start address */
    _Unwind_EHT_Header *ehtp; /* pointer to EHT entry header word */
    uint32_t additional;      /* additional data */
    uint32_t reserved1;
  } pr_cache;
  long long int : 0; /* force alignment of next item to 8-byte boundary */
} __attribute__((__aligned__(8)));
#else
struct _Unwind_Exception {
  _Unwind_Exception_Class exception_class;
  _Unwind_Exception_Cleanup_Fn exception_cleanup;
#if !defined (__USING_SJLJ_EXCEPTIONS__) && defined (__SEH__)
  _Unwind_Word private_[6];
#else
  _Unwind_Word private_1;
  _Unwind_Word private_2;
#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. */
} __attribute__((__aligned__));
#endif

typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)(int, _Unwind_Action,
                                               _Unwind_Exception_Class,
                                               _Unwind_Exception *,
                                               struct _Unwind_Context *,
                                               void *);

typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)(int, _Unwind_Action,
                                                      _Unwind_Exception_Class,
                                                      _Unwind_Exception *,
                                                      struct _Unwind_Context *);
typedef _Unwind_Personality_Fn __personality_routine;

typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)(struct _Unwind_Context *,
                                                void *);

#if defined(__arm__) && !(defined(__USING_SJLJ_EXCEPTIONS__) || defined(__ARM_DWARF_EH__))
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;

typedef uint32_t _Unwind_State;
#define _US_VIRTUAL_UNWIND_FRAME  ((_Unwind_State)0)
#define _US_UNWIND_FRAME_STARTING ((_Unwind_State)1)
#define _US_UNWIND_FRAME_RESUME   ((_Unwind_State)2)
#define _US_ACTION_MASK           ((_Unwind_State)3)
#define _US_FORCE_UNWIND          ((_Unwind_State)8)

_Unwind_VRS_Result _Unwind_VRS_Get(struct _Unwind_Context *__context,
  _Unwind_VRS_RegClass __regclass,
  uint32_t __regno,
  _Unwind_VRS_DataRepresentation __representation,
  void *__valuep);

_Unwind_VRS_Result _Unwind_VRS_Set(struct _Unwind_Context *__context,
  _Unwind_VRS_RegClass __regclass,
  uint32_t __regno,
  _Unwind_VRS_DataRepresentation __representation,
  void *__valuep);

static __inline__
_Unwind_Word _Unwind_GetGR(struct _Unwind_Context *__context, int __index) {
  _Unwind_Word __value;
  _Unwind_VRS_Get(__context, _UVRSC_CORE, __index, _UVRSD_UINT32, &__value);
  return __value;
}

static __inline__
void _Unwind_SetGR(struct _Unwind_Context *__context, int __index,
                   _Unwind_Word __value) {
  _Unwind_VRS_Set(__context, _UVRSC_CORE, __index, _UVRSD_UINT32, &__value);
}

static __inline__
_Unwind_Word _Unwind_GetIP(struct _Unwind_Context *__context) {
  _Unwind_Word __ip = _Unwind_GetGR(__context, 15);
  return __ip & ~(_Unwind_Word)(0x1); /* Remove thumb mode bit. */
}

static __inline__
void _Unwind_SetIP(struct _Unwind_Context *__context, _Unwind_Word __value) {
  _Unwind_Word __thumb_mode_bit = _Unwind_GetGR(__context, 15) & 0x1;
  _Unwind_SetGR(__context, 15, __value | __thumb_mode_bit);
}
#else
_Unwind_Word _Unwind_GetGR(struct _Unwind_Context *, int);
void _Unwind_SetGR(struct _Unwind_Context *, int, _Unwind_Word);

_Unwind_Word _Unwind_GetIP(struct _Unwind_Context *);
void _Unwind_SetIP(struct _Unwind_Context *, _Unwind_Word);
#endif


_Unwind_Word _Unwind_GetIPInfo(struct _Unwind_Context *, int *);

_Unwind_Word _Unwind_GetCFA(struct _Unwind_Context *);

_Unwind_Word _Unwind_GetBSP(struct _Unwind_Context *);

void *_Unwind_GetLanguageSpecificData(struct _Unwind_Context *);

_Unwind_Ptr _Unwind_GetRegionStart(struct _Unwind_Context *);

/* DWARF EH functions; currently not available on Darwin/ARM */
#if !defined(__APPLE__) || !defined(__arm__)
_Unwind_Reason_Code _Unwind_RaiseException(_Unwind_Exception *);
_Unwind_Reason_Code _Unwind_ForcedUnwind(_Unwind_Exception *, _Unwind_Stop_Fn,
                                         void *);
void _Unwind_DeleteException(_Unwind_Exception *);
void _Unwind_Resume(_Unwind_Exception *);
_Unwind_Reason_Code _Unwind_Resume_or_Rethrow(_Unwind_Exception *);

#endif

_Unwind_Reason_Code _Unwind_Backtrace(_Unwind_Trace_Fn, void *);

/* setjmp(3)/longjmp(3) stuff */
typedef struct SjLj_Function_Context *_Unwind_FunctionContext_t;

void _Unwind_SjLj_Register(_Unwind_FunctionContext_t);
void _Unwind_SjLj_Unregister(_Unwind_FunctionContext_t);
_Unwind_Reason_Code _Unwind_SjLj_RaiseException(_Unwind_Exception *);
_Unwind_Reason_Code _Unwind_SjLj_ForcedUnwind(_Unwind_Exception *,
                                              _Unwind_Stop_Fn, void *);
void _Unwind_SjLj_Resume(_Unwind_Exception *);
_Unwind_Reason_Code _Unwind_SjLj_Resume_or_Rethrow(_Unwind_Exception *);

void *_Unwind_FindEnclosingFunction(void *);

#ifdef __APPLE__

_Unwind_Ptr _Unwind_GetDataRelBase(struct _Unwind_Context *)
    __attribute__((__unavailable__));
_Unwind_Ptr _Unwind_GetTextRelBase(struct _Unwind_Context *)
    __attribute__((__unavailable__));

/* Darwin-specific functions */
void __register_frame(const void *);
void __deregister_frame(const void *);

struct dwarf_eh_bases {
  uintptr_t tbase;
  uintptr_t dbase;
  uintptr_t func;
};
void *_Unwind_Find_FDE(const void *, struct dwarf_eh_bases *);

void __register_frame_info_bases(const void *, void *, void *, void *)
  __attribute__((__unavailable__));
void __register_frame_info(const void *, void *) __attribute__((__unavailable__));
void __register_frame_info_table_bases(const void *, void*, void *, void *)
  __attribute__((__unavailable__));
void __register_frame_info_table(const void *, void *)
  __attribute__((__unavailable__));
void __register_frame_table(const void *) __attribute__((__unavailable__));
void __deregister_frame_info(const void *) __attribute__((__unavailable__));
void __deregister_frame_info_bases(const void *)__attribute__((__unavailable__));

#else

_Unwind_Ptr _Unwind_GetDataRelBase(struct _Unwind_Context *);
_Unwind_Ptr _Unwind_GetTextRelBase(struct _Unwind_Context *);

#endif


#ifndef HIDE_EXPORTS
#pragma GCC visibility pop
#endif

#ifdef __cplusplus
}
#endif

#endif

#endif /* __CLANG_UNWIND_H */