1 //===------------------------------- unwind.h -----------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //
9 // C++ ABI Level 1 ABI documented at:
10 //   http://mentorembedded.github.io/cxx-abi/abi-eh.html
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef __UNWIND_H__
15 #define __UNWIND_H__
16 
17 #include <__libunwind_config.h>
18 
19 #include <stdint.h>
20 #include <stddef.h>
21 
22 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__) && defined(_WIN32)
23 #include <windows.h>
24 #include <ntverp.h>
25 #endif
26 
27 #if defined(__APPLE__)
28 #define LIBUNWIND_UNAVAIL __attribute__ (( unavailable ))
29 #else
30 #define LIBUNWIND_UNAVAIL
31 #endif
32 
33 typedef enum {
34   _URC_NO_REASON = 0,
35   _URC_OK = 0,
36   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
37   _URC_FATAL_PHASE2_ERROR = 2,
38   _URC_FATAL_PHASE1_ERROR = 3,
39   _URC_NORMAL_STOP = 4,
40   _URC_END_OF_STACK = 5,
41   _URC_HANDLER_FOUND = 6,
42   _URC_INSTALL_CONTEXT = 7,
43   _URC_CONTINUE_UNWIND = 8,
44 #if defined(_LIBUNWIND_ARM_EHABI)
45   _URC_FAILURE = 9
46 #endif
47 } _Unwind_Reason_Code;
48 
49 typedef enum {
50   _UA_SEARCH_PHASE = 1,
51   _UA_CLEANUP_PHASE = 2,
52   _UA_HANDLER_FRAME = 4,
53   _UA_FORCE_UNWIND = 8,
54   _UA_END_OF_STACK = 16 // gcc extension to C++ ABI
55 } _Unwind_Action;
56 
57 typedef struct _Unwind_Context _Unwind_Context;   // opaque
58 
59 #if defined(_LIBUNWIND_ARM_EHABI)
60 typedef uint32_t _Unwind_State;
61 
62 static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME   = 0;
63 static const _Unwind_State _US_UNWIND_FRAME_STARTING  = 1;
64 static const _Unwind_State _US_UNWIND_FRAME_RESUME    = 2;
65 static const _Unwind_State _US_ACTION_MASK            = 3;
66 /* Undocumented flag for force unwinding. */
67 static const _Unwind_State _US_FORCE_UNWIND           = 8;
68 
69 typedef uint32_t _Unwind_EHT_Header;
70 
71 struct _Unwind_Control_Block;
72 typedef struct _Unwind_Control_Block _Unwind_Control_Block;
73 typedef struct _Unwind_Control_Block _Unwind_Exception; /* Alias */
74 
75 struct _Unwind_Control_Block {
76   uint64_t exception_class;
77   void (*exception_cleanup)(_Unwind_Reason_Code, _Unwind_Control_Block*);
78 
79   /* Unwinder cache, private fields for the unwinder's use */
80   struct {
81     uint32_t reserved1; /* init reserved1 to 0, then don't touch */
82     uint32_t reserved2;
83     uint32_t reserved3;
84     uint32_t reserved4;
85     uint32_t reserved5;
86   } unwinder_cache;
87 
88   /* Propagation barrier cache (valid after phase 1): */
89   struct {
90     uint32_t sp;
91     uint32_t bitpattern[5];
92   } barrier_cache;
93 
94   /* Cleanup cache (preserved over cleanup): */
95   struct {
96     uint32_t bitpattern[4];
97   } cleanup_cache;
98 
99   /* Pr cache (for pr's benefit): */
100   struct {
101     uint32_t fnstart; /* function start address */
102     _Unwind_EHT_Header* ehtp; /* pointer to EHT entry header word */
103     uint32_t additional;
104     uint32_t reserved1;
105   } pr_cache;
106 
107   long long int :0; /* Enforce the 8-byte alignment */
108 } __attribute__((__aligned__(8)));
109 
110 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
111       (_Unwind_State state,
112        _Unwind_Exception* exceptionObject,
113        struct _Unwind_Context* context);
114 
115 typedef _Unwind_Reason_Code (*__personality_routine)
116       (_Unwind_State state,
117        _Unwind_Exception* exceptionObject,
118        struct _Unwind_Context* context);
119 #else
120 struct _Unwind_Context;   // opaque
121 struct _Unwind_Exception; // forward declaration
122 typedef struct _Unwind_Exception _Unwind_Exception;
123 
124 struct _Unwind_Exception {
125   uint64_t exception_class;
126   void (*exception_cleanup)(_Unwind_Reason_Code reason,
127                             _Unwind_Exception *exc);
128 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
129   uintptr_t private_[6];
130 #else
131   uintptr_t private_1; // non-zero means forced unwind
132   uintptr_t private_2; // holds sp that phase1 found for phase2 to use
133 #endif
134 #if __SIZEOF_POINTER__ == 4
135   // The implementation of _Unwind_Exception uses an attribute mode on the
136   // above fields which has the side effect of causing this whole struct to
137   // round up to 32 bytes in size (48 with SEH). To be more explicit, we add
138   // pad fields added for binary compatibility.
139   uint32_t reserved[3];
140 #endif
141   // The Itanium ABI requires that _Unwind_Exception objects are "double-word
142   // aligned".  GCC has interpreted this to mean "use the maximum useful
143   // alignment for the target"; so do we.
144 } __attribute__((__aligned__));
145 
146 typedef _Unwind_Reason_Code (*_Unwind_Stop_Fn)
147     (int version,
148      _Unwind_Action actions,
149      uint64_t exceptionClass,
150      _Unwind_Exception* exceptionObject,
151      struct _Unwind_Context* context,
152      void* stop_parameter );
153 
154 typedef _Unwind_Reason_Code (*__personality_routine)
155       (int version,
156        _Unwind_Action actions,
157        uint64_t exceptionClass,
158        _Unwind_Exception* exceptionObject,
159        struct _Unwind_Context* context);
160 #endif
161 
162 #ifdef __cplusplus
163 extern "C" {
164 #endif
165 
166 //
167 // The following are the base functions documented by the C++ ABI
168 //
169 #ifdef __USING_SJLJ_EXCEPTIONS__
170 extern _Unwind_Reason_Code
171     _Unwind_SjLj_RaiseException(_Unwind_Exception *exception_object);
172 extern void _Unwind_SjLj_Resume(_Unwind_Exception *exception_object);
173 #else
174 extern _Unwind_Reason_Code
175     _Unwind_RaiseException(_Unwind_Exception *exception_object);
176 extern void _Unwind_Resume(_Unwind_Exception *exception_object);
177 #endif
178 extern void _Unwind_DeleteException(_Unwind_Exception *exception_object);
179 
180 #if defined(_LIBUNWIND_ARM_EHABI)
181 typedef enum {
182   _UVRSC_CORE = 0, /* integer register */
183   _UVRSC_VFP = 1, /* vfp */
184   _UVRSC_WMMXD = 3, /* Intel WMMX data register */
185   _UVRSC_WMMXC = 4 /* Intel WMMX control register */
186 } _Unwind_VRS_RegClass;
187 
188 typedef enum {
189   _UVRSD_UINT32 = 0,
190   _UVRSD_VFPX = 1,
191   _UVRSD_UINT64 = 3,
192   _UVRSD_FLOAT = 4,
193   _UVRSD_DOUBLE = 5
194 } _Unwind_VRS_DataRepresentation;
195 
196 typedef enum {
197   _UVRSR_OK = 0,
198   _UVRSR_NOT_IMPLEMENTED = 1,
199   _UVRSR_FAILED = 2
200 } _Unwind_VRS_Result;
201 
202 extern void _Unwind_Complete(_Unwind_Exception* exception_object);
203 
204 extern _Unwind_VRS_Result
205 _Unwind_VRS_Get(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
206                 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
207                 void *valuep);
208 
209 extern _Unwind_VRS_Result
210 _Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
211                 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
212                 void *valuep);
213 
214 extern _Unwind_VRS_Result
215 _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
216                 uint32_t discriminator,
217                 _Unwind_VRS_DataRepresentation representation);
218 #endif
219 
220 #if !defined(_LIBUNWIND_ARM_EHABI)
221 
222 extern uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index);
223 extern void _Unwind_SetGR(struct _Unwind_Context *context, int index,
224                           uintptr_t new_value);
225 extern uintptr_t _Unwind_GetIP(struct _Unwind_Context *context);
226 extern void _Unwind_SetIP(struct _Unwind_Context *, uintptr_t new_value);
227 
228 #else  // defined(_LIBUNWIND_ARM_EHABI)
229 
230 #if defined(_LIBUNWIND_UNWIND_LEVEL1_EXTERNAL_LINKAGE)
231 #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 extern
232 #else
233 #define _LIBUNWIND_EXPORT_UNWIND_LEVEL1 static __inline__
234 #endif
235 
236 // These are de facto helper functions for ARM, which delegate the function
237 // calls to _Unwind_VRS_Get/Set().  These are not a part of ARM EHABI
238 // specification, thus these function MUST be inlined.  Please don't replace
239 // these with the "extern" function declaration; otherwise, the program
240 // including this <unwind.h> header won't be ABI compatible and will result in
241 // link error when we are linking the program with libgcc.
242 
243 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
_Unwind_GetGR(struct _Unwind_Context * context,int index)244 uintptr_t _Unwind_GetGR(struct _Unwind_Context *context, int index) {
245   uintptr_t value = 0;
246   _Unwind_VRS_Get(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
247   return value;
248 }
249 
250 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
_Unwind_SetGR(struct _Unwind_Context * context,int index,uintptr_t value)251 void _Unwind_SetGR(struct _Unwind_Context *context, int index,
252                    uintptr_t value) {
253   _Unwind_VRS_Set(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
254 }
255 
256 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
_Unwind_GetIP(struct _Unwind_Context * context)257 uintptr_t _Unwind_GetIP(struct _Unwind_Context *context) {
258   // remove the thumb-bit before returning
259   return _Unwind_GetGR(context, 15) & (~(uintptr_t)0x1);
260 }
261 
262 _LIBUNWIND_EXPORT_UNWIND_LEVEL1
_Unwind_SetIP(struct _Unwind_Context * context,uintptr_t value)263 void _Unwind_SetIP(struct _Unwind_Context *context, uintptr_t value) {
264   uintptr_t thumb_bit = _Unwind_GetGR(context, 15) & ((uintptr_t)0x1);
265   _Unwind_SetGR(context, 15, value | thumb_bit);
266 }
267 #endif  // defined(_LIBUNWIND_ARM_EHABI)
268 
269 extern uintptr_t _Unwind_GetRegionStart(struct _Unwind_Context *context);
270 extern uintptr_t
271     _Unwind_GetLanguageSpecificData(struct _Unwind_Context *context);
272 #ifdef __USING_SJLJ_EXCEPTIONS__
273 extern _Unwind_Reason_Code
274     _Unwind_SjLj_ForcedUnwind(_Unwind_Exception *exception_object,
275                               _Unwind_Stop_Fn stop, void *stop_parameter);
276 #else
277 extern _Unwind_Reason_Code
278     _Unwind_ForcedUnwind(_Unwind_Exception *exception_object,
279                          _Unwind_Stop_Fn stop, void *stop_parameter);
280 #endif
281 
282 #ifdef __USING_SJLJ_EXCEPTIONS__
283 typedef struct _Unwind_FunctionContext *_Unwind_FunctionContext_t;
284 extern void _Unwind_SjLj_Register(_Unwind_FunctionContext_t fc);
285 extern void _Unwind_SjLj_Unregister(_Unwind_FunctionContext_t fc);
286 #endif
287 
288 //
289 // The following are semi-suppoted extensions to the C++ ABI
290 //
291 
292 //
293 //  called by __cxa_rethrow().
294 //
295 #ifdef __USING_SJLJ_EXCEPTIONS__
296 extern _Unwind_Reason_Code
297     _Unwind_SjLj_Resume_or_Rethrow(_Unwind_Exception *exception_object);
298 #else
299 extern _Unwind_Reason_Code
300     _Unwind_Resume_or_Rethrow(_Unwind_Exception *exception_object);
301 #endif
302 
303 // _Unwind_Backtrace() is a gcc extension that walks the stack and calls the
304 // _Unwind_Trace_Fn once per frame until it reaches the bottom of the stack
305 // or the _Unwind_Trace_Fn function returns something other than _URC_NO_REASON.
306 typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn)(struct _Unwind_Context *,
307                                                 void *);
308 extern _Unwind_Reason_Code _Unwind_Backtrace(_Unwind_Trace_Fn, void *);
309 
310 // _Unwind_GetCFA is a gcc extension that can be called from within a
311 // personality handler to get the CFA (stack pointer before call) of
312 // current frame.
313 extern uintptr_t _Unwind_GetCFA(struct _Unwind_Context *);
314 
315 
316 // _Unwind_GetIPInfo is a gcc extension that can be called from within a
317 // personality handler.  Similar to _Unwind_GetIP() but also returns in
318 // *ipBefore a non-zero value if the instruction pointer is at or before the
319 // instruction causing the unwind. Normally, in a function call, the IP returned
320 // is the return address which is after the call instruction and may be past the
321 // end of the function containing the call instruction.
322 extern uintptr_t _Unwind_GetIPInfo(struct _Unwind_Context *context,
323                                    int *ipBefore);
324 
325 
326 // __register_frame() is used with dynamically generated code to register the
327 // FDE for a generated (JIT) code.  The FDE must use pc-rel addressing to point
328 // to its function and optional LSDA.
329 // __register_frame() has existed in all versions of Mac OS X, but in 10.4 and
330 // 10.5 it was buggy and did not actually register the FDE with the unwinder.
331 // In 10.6 and later it does register properly.
332 extern void __register_frame(const void *fde);
333 extern void __deregister_frame(const void *fde);
334 
335 // _Unwind_Find_FDE() will locate the FDE if the pc is in some function that has
336 // an associated FDE. Note, Mac OS X 10.6 and later, introduces "compact unwind
337 // info" which the runtime uses in preference to DWARF unwind info.  This
338 // function will only work if the target function has an FDE but no compact
339 // unwind info.
340 struct dwarf_eh_bases {
341   uintptr_t tbase;
342   uintptr_t dbase;
343   uintptr_t func;
344 };
345 extern const void *_Unwind_Find_FDE(const void *pc, struct dwarf_eh_bases *);
346 
347 
348 // This function attempts to find the start (address of first instruction) of
349 // a function given an address inside the function.  It only works if the
350 // function has an FDE (DWARF unwind info).
351 // This function is unimplemented on Mac OS X 10.6 and later.  Instead, use
352 // _Unwind_Find_FDE() and look at the dwarf_eh_bases.func result.
353 extern void *_Unwind_FindEnclosingFunction(void *pc);
354 
355 // Mac OS X does not support text-rel and data-rel addressing so these functions
356 // are unimplemented
357 extern uintptr_t _Unwind_GetDataRelBase(struct _Unwind_Context *context)
358     LIBUNWIND_UNAVAIL;
359 extern uintptr_t _Unwind_GetTextRelBase(struct _Unwind_Context *context)
360     LIBUNWIND_UNAVAIL;
361 
362 // Mac OS X 10.4 and 10.5 had implementations of these functions in
363 // libgcc_s.dylib, but they never worked.
364 /// These functions are no longer available on Mac OS X.
365 extern void __register_frame_info_bases(const void *fde, void *ob, void *tb,
366                                         void *db) LIBUNWIND_UNAVAIL;
367 extern void __register_frame_info(const void *fde, void *ob)
368     LIBUNWIND_UNAVAIL;
369 extern void __register_frame_info_table_bases(const void *fde, void *ob,
370                                               void *tb, void *db)
371     LIBUNWIND_UNAVAIL;
372 extern void __register_frame_info_table(const void *fde, void *ob)
373     LIBUNWIND_UNAVAIL;
374 extern void __register_frame_table(const void *fde)
375     LIBUNWIND_UNAVAIL;
376 extern void *__deregister_frame_info(const void *fde)
377     LIBUNWIND_UNAVAIL;
378 extern void *__deregister_frame_info_bases(const void *fde)
379     LIBUNWIND_UNAVAIL;
380 
381 #if defined(__SEH__) && !defined(__USING_SJLJ_EXCEPTIONS__)
382 #ifndef _WIN32
383 typedef struct _EXCEPTION_RECORD EXCEPTION_RECORD;
384 typedef struct _CONTEXT CONTEXT;
385 typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
386 #elif !defined(__MINGW32__) && VER_PRODUCTBUILD < 8000
387 typedef struct _DISPATCHER_CONTEXT DISPATCHER_CONTEXT;
388 #endif
389 // This is the common wrapper for GCC-style personality functions with SEH.
390 extern EXCEPTION_DISPOSITION _GCC_specific_handler(EXCEPTION_RECORD *exc,
391                                                    void *frame,
392                                                    CONTEXT *ctx,
393                                                    DISPATCHER_CONTEXT *disp,
394                                                    __personality_routine pers);
395 #endif
396 
397 #ifdef __cplusplus
398 }
399 #endif
400 
401 #endif // __UNWIND_H__
402