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
32typedef 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
48typedef 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
56typedef struct _Unwind_Context _Unwind_Context;   // opaque
57
58#if defined(_LIBUNWIND_ARM_EHABI)
59typedef uint32_t _Unwind_State;
60
61static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME   = 0;
62static const _Unwind_State _US_UNWIND_FRAME_STARTING  = 1;
63static const _Unwind_State _US_UNWIND_FRAME_RESUME    = 2;
64static const _Unwind_State _US_ACTION_MASK            = 3;
65/* Undocumented flag for force unwinding. */
66static const _Unwind_State _US_FORCE_UNWIND           = 8;
67
68typedef uint32_t _Unwind_EHT_Header;
69/*
70 * gcc_personality_v0 references 'struct _Unwind_Exception' all over the place.
71 * Nothing in libunwind cares about 'struct _Unwind_Control_Block,' so make it
72 * the alias of struct _Unwind_Exception, instead of the other way around.
73 */
74struct _Unwind_Exception;
75typedef struct _Unwind_Exception _Unwind_Exception;
76typedef struct _Unwind_Exception _Unwind_Control_Block; /* Alias */
77
78struct _Unwind_Exception {
79  uint64_t exception_class;
80  void (*exception_cleanup)(_Unwind_Reason_Code, _Unwind_Control_Block*);
81
82  /* Unwinder cache, private fields for the unwinder's use */
83  struct {
84    uint32_t reserved1; /* init reserved1 to 0, then don't touch */
85    uint32_t reserved2;
86    uint32_t reserved3;
87    uint32_t reserved4;
88    uint32_t reserved5;
89  } unwinder_cache;
90
91  /* Propagation barrier cache (valid after phase 1): */
92  struct {
93    uint32_t sp;
94    uint32_t bitpattern[5];
95  } barrier_cache;
96
97  /* Cleanup cache (preserved over cleanup): */
98  struct {
99    uint32_t bitpattern[4];
100  } cleanup_cache;
101
102  /* Pr cache (for pr's benefit): */
103  struct {
104    uint32_t fnstart; /* function start address */
105    _Unwind_EHT_Header* ehtp; /* pointer to EHT entry header word */
106    uint32_t additional;
107    uint32_t reserved1;
108  } pr_cache;
109
110  long long int :0; /* Enforce the 8-byte alignment */
111} __attribute__((__aligned__(8)));
112
113typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
114      (_Unwind_State state,
115       _Unwind_Exception* exceptionObject,
116       struct _Unwind_Context* context);
117
118typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)(
119    _Unwind_State state, _Unwind_Exception *exceptionObject,
120    struct _Unwind_Context *context);
121#else
122struct _Unwind_Context;   // opaque
123struct _Unwind_Exception; // forward declaration
124typedef struct _Unwind_Exception _Unwind_Exception;
125
126struct _Unwind_Exception {
127  uint64_t exception_class;
128  void (*exception_cleanup)(_Unwind_Reason_Code reason,
129                            _Unwind_Exception *exc);
130#if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
131  uintptr_t private_[6];
132#else
133  uintptr_t private_1; // non-zero means forced unwind
134  uintptr_t private_2; // holds sp that phase1 found for phase2 to use
135#endif
136#if __SIZEOF_POINTER__ == 4
137  // The implementation of _Unwind_Exception uses an attribute mode on the
138  // above fields which has the side effect of causing this whole struct to
139  // round up to 32 bytes in size (48 with SEH). To be more explicit, we add
140  // pad fields added for binary compatibility.
141  uint32_t reserved[3];
142#endif
143  // The Itanium ABI requires that _Unwind_Exception objects are "double-word
144  // aligned".  GCC has interpreted this to mean "use the maximum useful
145  // alignment for the target"; so do we.
146} __attribute__((__aligned__));
147
148typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
149    (int version,
150     _Unwind_Action actions,
151     uint64_t exceptionClass,
152     _Unwind_Exception* exceptionObject,
153     struct _Unwind_Context* context,
154     void* stop_parameter );
155
156typedef _Unwind_Reason_Code (*_Unwind_Personality_Fn)(
157    int version, _Unwind_Action actions, uint64_t exceptionClass,
158    _Unwind_Exception *exceptionObject, struct _Unwind_Context *context);
159#endif
160
161#ifdef __cplusplus
162extern "C" {
163#endif
164
165//
166// The following are the base functions documented by the C++ ABI
167//
168#ifdef __USING_SJLJ_EXCEPTIONS__
169extern _Unwind_Reason_Code
170    _Unwind_SjLj_RaiseException(_Unwind_Exception *exception_object);
171extern void _Unwind_SjLj_Resume(_Unwind_Exception *exception_object);
172#else
173extern _Unwind_Reason_Code
174    _Unwind_RaiseException(_Unwind_Exception *exception_object);
175extern void _Unwind_Resume(_Unwind_Exception *exception_object);
176#endif
177extern void _Unwind_DeleteException(_Unwind_Exception *exception_object);
178
179#if defined(_LIBUNWIND_ARM_EHABI)
180typedef 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
187typedef 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
195typedef enum {
196  _UVRSR_OK = 0,
197  _UVRSR_NOT_IMPLEMENTED = 1,
198  _UVRSR_FAILED = 2
199} _Unwind_VRS_Result;
200
201extern void _Unwind_Complete(_Unwind_Exception* exception_object);
202
203extern _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
208extern _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
213extern _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
221extern uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index);
222extern void _Unwind_SetGR(struct _Unwind_Context *context, int index,
223                          uintptr_t new_value);
224extern uintptr_t _Unwind_GetIP(struct _Unwind_Context *context);
225extern 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
243uintptr_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
250void _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
256uintptr_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
262void _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
268extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context);
269extern uintptr_t
270    _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context);
271#ifdef __USING_SJLJ_EXCEPTIONS__
272extern _Unwind_Reason_Code
273    _Unwind_SjLj_ForcedUnwind(_Unwind_Exception *exception_object,
274                              _Unwind_Stop_Fn stop, void *stop_parameter);
275#else
276extern _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__
282typedef struct _Unwind_FunctionContext *_Unwind_FunctionContext_t;
283extern void _Unwind_SjLj_Register(_Unwind_FunctionContext_t fc);
284extern 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__
295extern _Unwind_Reason_Code
296    _Unwind_SjLj_Resume_or_Rethrow(_Unwind_Exception *exception_object);
297#else
298extern _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.
305typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)(struct _Unwind_Context *,
306                                                void *);
307extern _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.
312extern 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.
321extern 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.
331extern void __register_frame(const void *fde);
332extern 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.
339struct dwarf_eh_bases {
340  uintptr_t tbase;
341  uintptr_t dbase;
342  uintptr_t func;
343};
344extern 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.
352extern 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
356extern uintptr_t _Unwind_GetDataRelBase(struct _Unwind_Context *context)
357    LIBUNWIND_UNAVAIL;
358extern 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.
364extern void __register_frame_info_bases(const void *fde, void *ob, void *tb,
365                                        void *db) LIBUNWIND_UNAVAIL;
366extern void __register_frame_info(const void *fde, void *ob)
367    LIBUNWIND_UNAVAIL;
368extern void __register_frame_info_table_bases(const void *fde, void *ob,
369                                              void *tb, void *db)
370    LIBUNWIND_UNAVAIL;
371extern void __register_frame_info_table(const void *fde, void *ob)
372    LIBUNWIND_UNAVAIL;
373extern void __register_frame_table(const void *fde)
374    LIBUNWIND_UNAVAIL;
375extern void *__deregister_frame_info(const void *fde)
376    LIBUNWIND_UNAVAIL;
377extern void *__deregister_frame_info_bases(const void *fde)
378    LIBUNWIND_UNAVAIL;
379
380#if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
381#ifndef _WIN32
382typedef struct _EXCEPTION_RECORD EXCEPTION_RECORD;
383typedef struct _CONTEXT CONTEXT;
384typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
385#elif !defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
386typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
387#endif
388// This is the common wrapper for GCC-style personality functions with SEH.
389extern EXCEPTION_DISPOSITION _GCC_specific_handler(EXCEPTION_RECORD *exc,
390                                                   void *frame, CONTEXT *ctx,
391                                                   DISPATCHER_CONTEXT *disp,
392                                                   _Unwind_Personality_Fn pers);
393#endif
394
395#ifdef __cplusplus
396}
397#endif
398
399#endif // __UNWIND_H__
400