1 //===--------------------- UnwindLevel1-gcc-ext.c -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
9 // Implements gcc extensions to the C++ ABI Exception Handling Level 1.
11 //===----------------------------------------------------------------------===//
21 #include "libunwind_ext.h"
22 #include "libunwind.h"
23 #include "Unwind-EHABI.h"
26 #if defined(_LIBUNWIND_BUILD_ZERO_COST_APIS)
28 #if defined(_LIBUNWIND_SUPPORT_SEH_UNWIND)
29 #define private_1 private_[0]
32 /// Called by __cxa_rethrow().
33 _LIBUNWIND_EXPORT _Unwind_Reason_Code
34 _Unwind_Resume_or_Rethrow(_Unwind_Exception *exception_object) {
35 #if defined(_LIBUNWIND_ARM_EHABI)
36 _LIBUNWIND_TRACE_API("_Unwind_Resume_or_Rethrow(ex_obj=%p), private_1=%ld",
37 (void *)exception_object,
38 (long)exception_object->unwinder_cache.reserved1);
40 _LIBUNWIND_TRACE_API("_Unwind_Resume_or_Rethrow(ex_obj=%p), private_1=%" PRIdPTR,
41 (void *)exception_object,
42 (intptr_t)exception_object->private_1);
45 #if defined(_LIBUNWIND_ARM_EHABI)
46 // _Unwind_RaiseException on EHABI will always set the reserved1 field to 0,
47 // which is in the same position as private_1 below.
48 return _Unwind_RaiseException(exception_object);
50 // If this is non-forced and a stopping place was found, then this is a
52 // Call _Unwind_RaiseException() as if this was a new exception
53 if (exception_object->private_1 == 0) {
54 return _Unwind_RaiseException(exception_object);
55 // Will return if there is no catch clause, so that __cxa_rethrow can call
59 // Call through to _Unwind_Resume() which distiguishes between forced and
60 // regular exceptions.
61 _Unwind_Resume(exception_object);
62 _LIBUNWIND_ABORT("_Unwind_Resume_or_Rethrow() called _Unwind_RaiseException()"
63 " which unexpectedly returned");
68 /// Called by personality handler during phase 2 to get base address for data
69 /// relative encodings.
70 _LIBUNWIND_EXPORT uintptr_t
71 _Unwind_GetDataRelBase(struct _Unwind_Context *context) {
73 _LIBUNWIND_TRACE_API("_Unwind_GetDataRelBase(context=%p)", (void *)context);
74 _LIBUNWIND_ABORT("_Unwind_GetDataRelBase() not implemented");
78 /// Called by personality handler during phase 2 to get base address for text
79 /// relative encodings.
80 _LIBUNWIND_EXPORT uintptr_t
81 _Unwind_GetTextRelBase(struct _Unwind_Context *context) {
83 _LIBUNWIND_TRACE_API("_Unwind_GetTextRelBase(context=%p)", (void *)context);
84 _LIBUNWIND_ABORT("_Unwind_GetTextRelBase() not implemented");
88 /// Scans unwind information to find the function that contains the
89 /// specified code address "pc".
90 _LIBUNWIND_EXPORT void *_Unwind_FindEnclosingFunction(void *pc) {
91 _LIBUNWIND_TRACE_API("_Unwind_FindEnclosingFunction(pc=%p)", pc);
92 // This is slow, but works.
93 // We create an unwind cursor then alter the IP to be pc
98 unw_init_local(&cursor, &uc);
99 unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(intptr_t) pc);
100 if (unw_get_proc_info(&cursor, &info) == UNW_ESUCCESS)
101 return (void *)(intptr_t) info.start_ip;
106 /// Walk every frame and call trace function at each one. If trace function
107 /// returns anything other than _URC_NO_REASON, then walk is terminated.
108 _LIBUNWIND_EXPORT _Unwind_Reason_Code
109 _Unwind_Backtrace(_Unwind_Trace_Fn callback, void *ref) {
113 unw_init_local(&cursor, &uc);
115 _LIBUNWIND_TRACE_API("_Unwind_Backtrace(callback=%p)",
116 (void *)(uintptr_t)callback);
118 #if defined(_LIBUNWIND_ARM_EHABI)
119 // Create a mock exception object for force unwinding.
120 _Unwind_Exception ex;
121 memset(&ex, '\0', sizeof(ex));
122 ex.exception_class = 0x434C4E47554E5700; // CLNGUNW\0
127 _Unwind_Reason_Code result;
129 #if !defined(_LIBUNWIND_ARM_EHABI)
130 // ask libunwind to get next frame (skip over first frame which is
131 // _Unwind_Backtrace())
132 if (unw_step(&cursor) <= 0) {
133 _LIBUNWIND_TRACE_UNWINDING(" _backtrace: ended because cursor reached "
134 "bottom of stack, returning %d",
136 return _URC_END_OF_STACK;
139 // Get the information for this frame.
140 unw_proc_info_t frameInfo;
141 if (unw_get_proc_info(&cursor, &frameInfo) != UNW_ESUCCESS) {
142 return _URC_END_OF_STACK;
145 // Update the pr_cache in the mock exception object.
146 const uint32_t* unwindInfo = (uint32_t *) frameInfo.unwind_info;
147 ex.pr_cache.fnstart = frameInfo.start_ip;
148 ex.pr_cache.ehtp = (_Unwind_EHT_Header *) unwindInfo;
149 ex.pr_cache.additional= frameInfo.flags;
151 struct _Unwind_Context *context = (struct _Unwind_Context *)&cursor;
152 // Get and call the personality function to unwind the frame.
153 __personality_routine handler = (__personality_routine) frameInfo.handler;
154 if (handler == NULL) {
155 return _URC_END_OF_STACK;
157 if (handler(_US_VIRTUAL_UNWIND_FRAME | _US_FORCE_UNWIND, &ex, context) !=
158 _URC_CONTINUE_UNWIND) {
159 return _URC_END_OF_STACK;
161 #endif // defined(_LIBUNWIND_ARM_EHABI)
164 if (_LIBUNWIND_TRACING_UNWINDING) {
165 char functionName[512];
166 unw_proc_info_t frame;
168 unw_get_proc_name(&cursor, functionName, 512, &offset);
169 unw_get_proc_info(&cursor, &frame);
170 _LIBUNWIND_TRACE_UNWINDING(
171 " _backtrace: start_ip=0x%" PRIxPTR ", func=%s, lsda=0x%" PRIxPTR ", context=%p",
172 frame.start_ip, functionName, frame.lsda,
176 // call trace function with this frame
177 result = (*callback)((struct _Unwind_Context *)(&cursor), ref);
178 if (result != _URC_NO_REASON) {
179 _LIBUNWIND_TRACE_UNWINDING(
180 " _backtrace: ended because callback returned %d", result);
187 /// Find DWARF unwind info for an address 'pc' in some function.
188 _LIBUNWIND_EXPORT const void *_Unwind_Find_FDE(const void *pc,
189 struct dwarf_eh_bases *bases) {
190 // This is slow, but works.
191 // We create an unwind cursor then alter the IP to be pc
194 unw_proc_info_t info;
196 unw_init_local(&cursor, &uc);
197 unw_set_reg(&cursor, UNW_REG_IP, (unw_word_t)(intptr_t) pc);
198 unw_get_proc_info(&cursor, &info);
199 bases->tbase = (uintptr_t)info.extra;
200 bases->dbase = 0; // dbase not used on Mac OS X
201 bases->func = (uintptr_t)info.start_ip;
202 _LIBUNWIND_TRACE_API("_Unwind_Find_FDE(pc=%p) => %p", pc,
203 (void *)(intptr_t) info.unwind_info);
204 return (void *)(intptr_t) info.unwind_info;
207 /// Returns the CFA (call frame area, or stack pointer at start of function)
208 /// for the current context.
209 _LIBUNWIND_EXPORT uintptr_t _Unwind_GetCFA(struct _Unwind_Context *context) {
210 unw_cursor_t *cursor = (unw_cursor_t *)context;
212 unw_get_reg(cursor, UNW_REG_SP, &result);
213 _LIBUNWIND_TRACE_API("_Unwind_GetCFA(context=%p) => 0x%" PRIxPTR,
214 (void *)context, result);
215 return (uintptr_t)result;
219 /// Called by personality handler during phase 2 to get instruction pointer.
220 /// ipBefore is a boolean that says if IP is already adjusted to be the call
221 /// site address. Normally IP is the return address.
222 _LIBUNWIND_EXPORT uintptr_t _Unwind_GetIPInfo(struct _Unwind_Context *context,
224 _LIBUNWIND_TRACE_API("_Unwind_GetIPInfo(context=%p)", (void *)context);
226 return _Unwind_GetIP(context);
229 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
233 // Based on LLVM's lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp
234 // and XXX should be fixed to be alignment-safe.
235 static void processFDE(const char *addr, bool isDeregister) {
237 while ((length = *((const uint32_t *)addr)) != 0) {
238 const char *p = addr + 4;
239 if (length == 0xffffffff) {
240 length = *((const uint64_t *)p);
243 uint32_t offset = *((const uint32_t *)p);
246 _unw_remove_dynamic_fde((unw_word_t)(uintptr_t)addr);
248 _unw_add_dynamic_fde((unw_word_t)(uintptr_t)addr);
254 /// Called by programs with dynamic code generators that want to register
255 /// dynamically generated FDEs, with a libgcc-compatible API.
257 _LIBUNWIND_EXPORT void __register_frame(const void *addr) {
258 _LIBUNWIND_TRACE_API("__register_frame(%p)", addr);
259 processFDE(addr, false);
262 /// Called by programs with dynamic code generators that want to unregister
263 /// dynamically generated FDEs, with a libgcc-compatible API.
264 _LIBUNWIND_EXPORT void __deregister_frame(const void *addr) {
265 _LIBUNWIND_TRACE_API("__deregister_frame(%p)", addr);
266 processFDE(addr, true);
272 /// Called by programs with dynamic code generators that want
273 /// to register a dynamically generated FDE.
274 /// This function has existed on Mac OS X since 10.4, but
275 /// was broken until 10.6.
276 _LIBUNWIND_EXPORT void __register_frame(const void *fde) {
277 _LIBUNWIND_TRACE_API("__register_frame(%p)", fde);
278 _unw_add_dynamic_fde((unw_word_t)(uintptr_t) fde);
282 /// Called by programs with dynamic code generators that want
283 /// to unregister a dynamically generated FDE.
284 /// This function has existed on Mac OS X since 10.4, but
285 /// was broken until 10.6.
286 _LIBUNWIND_EXPORT void __deregister_frame(const void *fde) {
287 _LIBUNWIND_TRACE_API("__deregister_frame(%p)", fde);
288 _unw_remove_dynamic_fde((unw_word_t)(uintptr_t) fde);
293 // The following register/deregister functions are gcc extensions.
294 // They have existed on Mac OS X, but have never worked because Mac OS X
295 // before 10.6 used keymgr to track known FDEs, but these functions
296 // never got updated to use keymgr.
297 // For now, we implement these as do-nothing functions to keep any existing
298 // applications working. We also add the not in 10.6 symbol so that nwe
299 // application won't be able to use them.
301 #if defined(_LIBUNWIND_SUPPORT_FRAME_APIS)
302 _LIBUNWIND_EXPORT void __register_frame_info_bases(const void *fde, void *ob,
303 void *tb, void *db) {
308 _LIBUNWIND_TRACE_API("__register_frame_info_bases(%p,%p, %p, %p)",
310 // do nothing, this function never worked in Mac OS X
313 _LIBUNWIND_EXPORT void __register_frame_info(const void *fde, void *ob) {
316 _LIBUNWIND_TRACE_API("__register_frame_info(%p, %p)", fde, ob);
317 // do nothing, this function never worked in Mac OS X
320 _LIBUNWIND_EXPORT void __register_frame_info_table_bases(const void *fde,
327 _LIBUNWIND_TRACE_API("__register_frame_info_table_bases"
328 "(%p,%p, %p, %p)", fde, ob, tb, db);
329 // do nothing, this function never worked in Mac OS X
332 _LIBUNWIND_EXPORT void __register_frame_info_table(const void *fde, void *ob) {
335 _LIBUNWIND_TRACE_API("__register_frame_info_table(%p, %p)", fde, ob);
336 // do nothing, this function never worked in Mac OS X
339 _LIBUNWIND_EXPORT void __register_frame_table(const void *fde) {
341 _LIBUNWIND_TRACE_API("__register_frame_table(%p)", fde);
342 // do nothing, this function never worked in Mac OS X
345 _LIBUNWIND_EXPORT void *__deregister_frame_info(const void *fde) {
347 _LIBUNWIND_TRACE_API("__deregister_frame_info(%p)", fde);
348 // do nothing, this function never worked in Mac OS X
352 _LIBUNWIND_EXPORT void *__deregister_frame_info_bases(const void *fde) {
354 _LIBUNWIND_TRACE_API("__deregister_frame_info_bases(%p)", fde);
355 // do nothing, this function never worked in Mac OS X
358 #endif // defined(_LIBUNWIND_SUPPORT_FRAME_APIS)
360 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
362 #endif // defined(_LIBUNWIND_BUILD_ZERO_COST_APIS)