unwind-arm.h revision 279456 
1/*
2 * Copyright 2012 David Chisnall. All rights reserved.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a copy
5 * of this software and associated documentation files (the "Software"), to
6 * deal in the Software without restriction, including without limitation the
7 * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
8 * sell copies of the Software, and to permit persons to whom the Software is
9 * furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be
12 * included in all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
15 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
16 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
17 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
18 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
19 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
20 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
21 */
22
23/**
24 * ARM-specific unwind definitions.  These are taken from the ARM EHABI
25 * specification.
26 */
27 typedef enum
28{
29	_URC_OK = 0,                /* operation completed successfully */
30	_URC_FOREIGN_EXCEPTION_CAUGHT = 1,
31    _URC_END_OF_STACK = 5,
32	_URC_HANDLER_FOUND = 6,
33	_URC_INSTALL_CONTEXT = 7,
34	_URC_CONTINUE_UNWIND = 8,
35	_URC_FAILURE = 9,            /* unspecified failure of some kind */
36	_URC_FATAL_PHASE1_ERROR = _URC_FAILURE
37} _Unwind_Reason_Code;
38
39typedef int _Unwind_Action;
40
41typedef uint32_t _Unwind_State;
42#ifdef __clang__
43static const _Unwind_State _US_VIRTUAL_UNWIND_FRAME  = 0;
44static const _Unwind_State _US_UNWIND_FRAME_STARTING = 1;
45static const _Unwind_State _US_UNWIND_FRAME_RESUME   = 2;
46#else // GCC fails at knowing what a constant expression is
47#	define _US_VIRTUAL_UNWIND_FRAME  0
48#	define _US_UNWIND_FRAME_STARTING 1
49#	define _US_UNWIND_FRAME_RESUME 2
50#endif
51
52typedef struct _Unwind_Context _Unwind_Context;
53
54typedef uint32_t _Unwind_EHT_Header;
55
56struct _Unwind_Exception
57{
58	uint64_t exception_class;
59	void (*exception_cleanup)(_Unwind_Reason_Code, struct _Unwind_Exception *);
60	/* Unwinder cache, private fields for the unwinder's use */
61	struct
62	{
63		uint32_t reserved1;
64		uint32_t reserved2;
65		uint32_t reserved3;
66		uint32_t reserved4;
67		uint32_t reserved5;
68	/* init reserved1 to 0, then don't touch */
69	} unwinder_cache;
70	/* Propagation barrier cache (valid after phase 1): */
71	struct
72	{
73		uint32_t sp;
74		uint32_t bitpattern[5];
75	} barrier_cache;
76	/* Cleanup cache (preserved over cleanup): */
77	struct
78	{
79		uint32_t bitpattern[4];
80	} cleanup_cache;
81	/* Pr cache (for pr's benefit): */
82	struct
83	{
84		/** function start address */
85		uint32_t fnstart;
86		/** pointer to EHT entry header word */
87		_Unwind_EHT_Header *ehtp;
88		/** additional data */
89		uint32_t additional;
90		uint32_t reserved1;
91	} pr_cache;
92	/** Force alignment of next item to 8-byte boundary */
93	long long int :0;
94};
95
96/* Unwinding functions */
97_Unwind_Reason_Code _Unwind_RaiseException(struct _Unwind_Exception *ucbp);
98void _Unwind_Resume(struct _Unwind_Exception *ucbp);
99void _Unwind_Complete(struct _Unwind_Exception *ucbp);
100void _Unwind_DeleteException(struct _Unwind_Exception *ucbp);
101void *_Unwind_GetLanguageSpecificData(struct _Unwind_Context*);
102
103typedef enum
104{
105	_UVRSR_OK = 0,
106	_UVRSR_NOT_IMPLEMENTED = 1,
107	_UVRSR_FAILED = 2
108} _Unwind_VRS_Result;
109typedef enum
110{
111	_UVRSC_CORE = 0,
112	_UVRSC_VFP = 1,
113	_UVRSC_WMMXD = 3,
114	_UVRSC_WMMXC = 4
115} _Unwind_VRS_RegClass;
116typedef enum
117{
118	_UVRSD_UINT32 = 0,
119	_UVRSD_VFPX = 1,
120	_UVRSD_UINT64 = 3,
121	_UVRSD_FLOAT = 4,
122	_UVRSD_DOUBLE = 5
123} _Unwind_VRS_DataRepresentation;
124
125_Unwind_VRS_Result _Unwind_VRS_Get(_Unwind_Context *context,
126                                   _Unwind_VRS_RegClass regclass,
127                                   uint32_t regno,
128                                   _Unwind_VRS_DataRepresentation representation,
129                                   void *valuep);
130_Unwind_VRS_Result _Unwind_VRS_Set(_Unwind_Context *context,
131                                   _Unwind_VRS_RegClass regclass,
132                                   uint32_t regno,
133                                   _Unwind_VRS_DataRepresentation representation,
134                                   void *valuep);
135
136/* Return the base-address for data references.  */
137extern unsigned long _Unwind_GetDataRelBase(struct _Unwind_Context *);
138
139/* Return the base-address for text references.  */
140extern unsigned long _Unwind_GetTextRelBase(struct _Unwind_Context *);
141extern unsigned long _Unwind_GetRegionStart(struct _Unwind_Context *);
142
143typedef _Unwind_Reason_Code (*_Unwind_Trace_Fn) (struct _Unwind_Context *,
144						 void *);
145extern _Unwind_Reason_Code _Unwind_Backtrace (_Unwind_Trace_Fn, void *);
146extern _Unwind_Reason_Code
147	  _Unwind_Resume_or_Rethrow (struct _Unwind_Exception *);
148
149/**
150 * The next set of functions are compatibility extensions, implementing Itanium
151 * ABI functions on top of ARM ones.
152 */
153
154#define _UA_SEARCH_PHASE	1
155#define _UA_CLEANUP_PHASE	2
156#define _UA_HANDLER_FRAME	4
157#define _UA_FORCE_UNWIND	8
158
159static inline unsigned long _Unwind_GetGR(struct _Unwind_Context *context, int reg)
160{
161	unsigned long val;
162	_Unwind_VRS_Get(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
163	return val;
164}
165static inline  void _Unwind_SetGR(struct _Unwind_Context *context, int reg, unsigned long val)
166{
167	_Unwind_VRS_Set(context, _UVRSC_CORE, reg, _UVRSD_UINT32, &val);
168}
169static inline unsigned long _Unwind_GetIP(_Unwind_Context *context)
170{
171	// Low bit store the thumb state - discard it
172	return _Unwind_GetGR(context, 15) & ~1;
173}
174static inline void _Unwind_SetIP(_Unwind_Context *context, unsigned long val)
175{
176	// The lowest bit of the instruction pointer indicates whether we're in
177	// thumb or ARM mode.  This is assumed to be fixed throughout a function,
178	// so must be propagated when setting the program counter.
179	unsigned long thumbState = _Unwind_GetGR(context, 15) & 1;
180   _Unwind_SetGR(context, 15, (val | thumbState));
181}
182
183/** GNU API function that unwinds the frame */
184_Unwind_Reason_Code __gnu_unwind_frame(struct _Unwind_Exception*, struct _Unwind_Context*);
185
186
187#define DECLARE_PERSONALITY_FUNCTION(name) \
188_Unwind_Reason_Code name(_Unwind_State state,\
189                         struct _Unwind_Exception *exceptionObject,\
190                         struct _Unwind_Context *context);
191
192#define BEGIN_PERSONALITY_FUNCTION(name) \
193_Unwind_Reason_Code name(_Unwind_State state,\
194                         struct _Unwind_Exception *exceptionObject,\
195                         struct _Unwind_Context *context)\
196{\
197	int version = 1;\
198	uint64_t exceptionClass = exceptionObject->exception_class;\
199	int actions;\
200	switch (state)\
201	{\
202		default: return _URC_FAILURE;\
203		case _US_VIRTUAL_UNWIND_FRAME:\
204		{\
205			actions = _UA_SEARCH_PHASE;\
206			break;\
207		}\
208		case _US_UNWIND_FRAME_STARTING:\
209		{\
210			actions = _UA_CLEANUP_PHASE;\
211			if (exceptionObject->barrier_cache.sp == _Unwind_GetGR(context, 13))\
212			{\
213				actions |= _UA_HANDLER_FRAME;\
214			}\
215			break;\
216		}\
217		case _US_UNWIND_FRAME_RESUME:\
218		{\
219			return continueUnwinding(exceptionObject, context);\
220			break;\
221		}\
222	}\
223	_Unwind_SetGR (context, 12, reinterpret_cast<unsigned long>(exceptionObject));\
224
225#define CALL_PERSONALITY_FUNCTION(name) name(state,exceptionObject,context)
226