1 //===--------------------------- libunwind.cpp ----------------------------===//
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 //  Implements unw_* functions from <libunwind.h>
9 //
10 //===----------------------------------------------------------------------===//
11 
12 #include <libunwind.h>
13 
14 #include "libunwind_ext.h"
15 #include "config.h"
16 
17 #include <stdlib.h>
18 
19 
20 #if !defined(__USING_SJLJ_EXCEPTIONS__)
21 #include "AddressSpace.hpp"
22 #include "UnwindCursor.hpp"
23 
24 using namespace libunwind;
25 
26 /// internal object to represent this processes address space
27 LocalAddressSpace LocalAddressSpace::sThisAddressSpace;
28 
29 _LIBUNWIND_EXPORT unw_addr_space_t unw_local_addr_space =
30     (unw_addr_space_t)&LocalAddressSpace::sThisAddressSpace;
31 
32 /// Create a cursor of a thread in this process given 'context' recorded by
33 /// __unw_getcontext().
34 _LIBUNWIND_HIDDEN int __unw_init_local(unw_cursor_t *cursor,
35                                        unw_context_t *context) {
36   _LIBUNWIND_TRACE_API("__unw_init_local(cursor=%p, context=%p)",
37                        static_cast<void *>(cursor),
38                        static_cast<void *>(context));
39 #if defined(__i386__)
40 # define REGISTER_KIND Registers_x86
41 #elif defined(__x86_64__)
42 # define REGISTER_KIND Registers_x86_64
43 #elif defined(__powerpc64__)
44 # define REGISTER_KIND Registers_ppc64
45 #elif defined(__ppc__)
46 # define REGISTER_KIND Registers_ppc
47 #elif defined(__aarch64__)
48 # define REGISTER_KIND Registers_arm64
49 #elif defined(__arm__)
50 # define REGISTER_KIND Registers_arm
51 #elif defined(__or1k__)
52 # define REGISTER_KIND Registers_or1k
53 #elif defined(__mips__) && defined(_ABIO32) && _MIPS_SIM == _ABIO32
54 # define REGISTER_KIND Registers_mips_o32
55 #elif defined(__mips64)
56 # define REGISTER_KIND Registers_mips_newabi
57 #elif defined(__mips__)
58 # warning The MIPS architecture is not supported with this ABI and environment!
59 #elif defined(__sparc__)
60 # define REGISTER_KIND Registers_sparc
61 #else
62 # error Architecture not supported
63 #endif
64   // Use "placement new" to allocate UnwindCursor in the cursor buffer.
65   new (reinterpret_cast<UnwindCursor<LocalAddressSpace, REGISTER_KIND> *>(cursor))
66       UnwindCursor<LocalAddressSpace, REGISTER_KIND>(
67           context, LocalAddressSpace::sThisAddressSpace);
68 #undef REGISTER_KIND
69   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
70   co->setInfoBasedOnIPRegister();
71 
72   return UNW_ESUCCESS;
73 }
74 _LIBUNWIND_WEAK_ALIAS(__unw_init_local, unw_init_local)
75 
76 /// Get value of specified register at cursor position in stack frame.
77 _LIBUNWIND_HIDDEN int __unw_get_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
78                                     unw_word_t *value) {
79   _LIBUNWIND_TRACE_API("__unw_get_reg(cursor=%p, regNum=%d, &value=%p)",
80                        static_cast<void *>(cursor), regNum,
81                        static_cast<void *>(value));
82   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
83   if (co->validReg(regNum)) {
84     *value = co->getReg(regNum);
85     return UNW_ESUCCESS;
86   }
87   return UNW_EBADREG;
88 }
89 _LIBUNWIND_WEAK_ALIAS(__unw_get_reg, unw_get_reg)
90 
91 /// Set value of specified register at cursor position in stack frame.
92 _LIBUNWIND_HIDDEN int __unw_set_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
93                                     unw_word_t value) {
94   _LIBUNWIND_TRACE_API("__unw_set_reg(cursor=%p, regNum=%d, value=0x%" PRIxPTR
95                        ")",
96                        static_cast<void *>(cursor), regNum, value);
97   typedef LocalAddressSpace::pint_t pint_t;
98   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
99   if (co->validReg(regNum)) {
100     co->setReg(regNum, (pint_t)value);
101     // specical case altering IP to re-find info (being called by personality
102     // function)
103     if (regNum == UNW_REG_IP) {
104       unw_proc_info_t info;
105       // First, get the FDE for the old location and then update it.
106       co->getInfo(&info);
107       co->setInfoBasedOnIPRegister(false);
108       // If the original call expects stack adjustment, perform this now.
109       // Normal frame unwinding would have included the offset already in the
110       // CFA computation.
111       // Note: for PA-RISC and other platforms where the stack grows up,
112       // this should actually be - info.gp. LLVM doesn't currently support
113       // any such platforms and Clang doesn't export a macro for them.
114       if (info.gp)
115         co->setReg(UNW_REG_SP, co->getReg(UNW_REG_SP) + info.gp);
116     }
117     return UNW_ESUCCESS;
118   }
119   return UNW_EBADREG;
120 }
121 _LIBUNWIND_WEAK_ALIAS(__unw_set_reg, unw_set_reg)
122 
123 /// Get value of specified float register at cursor position in stack frame.
124 _LIBUNWIND_HIDDEN int __unw_get_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
125                                       unw_fpreg_t *value) {
126   _LIBUNWIND_TRACE_API("__unw_get_fpreg(cursor=%p, regNum=%d, &value=%p)",
127                        static_cast<void *>(cursor), regNum,
128                        static_cast<void *>(value));
129   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
130   if (co->validFloatReg(regNum)) {
131     *value = co->getFloatReg(regNum);
132     return UNW_ESUCCESS;
133   }
134   return UNW_EBADREG;
135 }
136 _LIBUNWIND_WEAK_ALIAS(__unw_get_fpreg, unw_get_fpreg)
137 
138 /// Set value of specified float register at cursor position in stack frame.
139 _LIBUNWIND_HIDDEN int __unw_set_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
140                                       unw_fpreg_t value) {
141 #if defined(_LIBUNWIND_ARM_EHABI)
142   _LIBUNWIND_TRACE_API("__unw_set_fpreg(cursor=%p, regNum=%d, value=%llX)",
143                        static_cast<void *>(cursor), regNum, value);
144 #else
145   _LIBUNWIND_TRACE_API("__unw_set_fpreg(cursor=%p, regNum=%d, value=%g)",
146                        static_cast<void *>(cursor), regNum, value);
147 #endif
148   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
149   if (co->validFloatReg(regNum)) {
150     co->setFloatReg(regNum, value);
151     return UNW_ESUCCESS;
152   }
153   return UNW_EBADREG;
154 }
155 _LIBUNWIND_WEAK_ALIAS(__unw_set_fpreg, unw_set_fpreg)
156 
157 /// Move cursor to next frame.
158 _LIBUNWIND_HIDDEN int __unw_step(unw_cursor_t *cursor) {
159   _LIBUNWIND_TRACE_API("__unw_step(cursor=%p)", static_cast<void *>(cursor));
160   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
161   return co->step();
162 }
163 _LIBUNWIND_WEAK_ALIAS(__unw_step, unw_step)
164 
165 /// Get unwind info at cursor position in stack frame.
166 _LIBUNWIND_HIDDEN int __unw_get_proc_info(unw_cursor_t *cursor,
167                                           unw_proc_info_t *info) {
168   _LIBUNWIND_TRACE_API("__unw_get_proc_info(cursor=%p, &info=%p)",
169                        static_cast<void *>(cursor), static_cast<void *>(info));
170   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
171   co->getInfo(info);
172   if (info->end_ip == 0)
173     return UNW_ENOINFO;
174   else
175     return UNW_ESUCCESS;
176 }
177 _LIBUNWIND_WEAK_ALIAS(__unw_get_proc_info, unw_get_proc_info)
178 
179 /// Resume execution at cursor position (aka longjump).
180 _LIBUNWIND_HIDDEN int __unw_resume(unw_cursor_t *cursor) {
181   _LIBUNWIND_TRACE_API("__unw_resume(cursor=%p)", static_cast<void *>(cursor));
182   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
183   co->jumpto();
184   return UNW_EUNSPEC;
185 }
186 _LIBUNWIND_WEAK_ALIAS(__unw_resume, unw_resume)
187 
188 /// Get name of function at cursor position in stack frame.
189 _LIBUNWIND_HIDDEN int __unw_get_proc_name(unw_cursor_t *cursor, char *buf,
190                                           size_t bufLen, unw_word_t *offset) {
191   _LIBUNWIND_TRACE_API("__unw_get_proc_name(cursor=%p, &buf=%p, bufLen=%lu)",
192                        static_cast<void *>(cursor), static_cast<void *>(buf),
193                        static_cast<unsigned long>(bufLen));
194   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
195   if (co->getFunctionName(buf, bufLen, offset))
196     return UNW_ESUCCESS;
197   else
198     return UNW_EUNSPEC;
199 }
200 _LIBUNWIND_WEAK_ALIAS(__unw_get_proc_name, unw_get_proc_name)
201 
202 /// Checks if a register is a floating-point register.
203 _LIBUNWIND_HIDDEN int __unw_is_fpreg(unw_cursor_t *cursor,
204                                      unw_regnum_t regNum) {
205   _LIBUNWIND_TRACE_API("__unw_is_fpreg(cursor=%p, regNum=%d)",
206                        static_cast<void *>(cursor), regNum);
207   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
208   return co->validFloatReg(regNum);
209 }
210 _LIBUNWIND_WEAK_ALIAS(__unw_is_fpreg, unw_is_fpreg)
211 
212 /// Checks if a register is a floating-point register.
213 _LIBUNWIND_HIDDEN const char *__unw_regname(unw_cursor_t *cursor,
214                                             unw_regnum_t regNum) {
215   _LIBUNWIND_TRACE_API("__unw_regname(cursor=%p, regNum=%d)",
216                        static_cast<void *>(cursor), regNum);
217   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
218   return co->getRegisterName(regNum);
219 }
220 _LIBUNWIND_WEAK_ALIAS(__unw_regname, unw_regname)
221 
222 /// Checks if current frame is signal trampoline.
223 _LIBUNWIND_HIDDEN int __unw_is_signal_frame(unw_cursor_t *cursor) {
224   _LIBUNWIND_TRACE_API("__unw_is_signal_frame(cursor=%p)",
225                        static_cast<void *>(cursor));
226   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
227   return co->isSignalFrame();
228 }
229 _LIBUNWIND_WEAK_ALIAS(__unw_is_signal_frame, unw_is_signal_frame)
230 
231 #ifdef __arm__
232 // Save VFP registers d0-d15 using FSTMIADX instead of FSTMIADD
233 _LIBUNWIND_HIDDEN void __unw_save_vfp_as_X(unw_cursor_t *cursor) {
234   _LIBUNWIND_TRACE_API("__unw_get_fpreg_save_vfp_as_X(cursor=%p)",
235                        static_cast<void *>(cursor));
236   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
237   return co->saveVFPAsX();
238 }
239 _LIBUNWIND_WEAK_ALIAS(__unw_save_vfp_as_X, unw_save_vfp_as_X)
240 #endif
241 
242 
243 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
244 /// SPI: walks cached DWARF entries
245 _LIBUNWIND_HIDDEN void __unw_iterate_dwarf_unwind_cache(void (*func)(
246     unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
247   _LIBUNWIND_TRACE_API("__unw_iterate_dwarf_unwind_cache(func=%p)",
248                        reinterpret_cast<void *>(func));
249   DwarfFDECache<LocalAddressSpace>::iterateCacheEntries(func);
250 }
251 _LIBUNWIND_WEAK_ALIAS(__unw_iterate_dwarf_unwind_cache,
252                       unw_iterate_dwarf_unwind_cache)
253 
254 /// IPI: for __register_frame()
255 void __unw_add_dynamic_fde(unw_word_t fde) {
256   CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
257   CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
258   const char *message = CFI_Parser<LocalAddressSpace>::decodeFDE(
259                            LocalAddressSpace::sThisAddressSpace,
260                           (LocalAddressSpace::pint_t) fde, &fdeInfo, &cieInfo);
261   if (message == NULL) {
262     // dynamically registered FDEs don't have a mach_header group they are in.
263     // Use fde as mh_group
264     unw_word_t mh_group = fdeInfo.fdeStart;
265     DwarfFDECache<LocalAddressSpace>::add((LocalAddressSpace::pint_t)mh_group,
266                                           fdeInfo.pcStart, fdeInfo.pcEnd,
267                                           fdeInfo.fdeStart);
268   } else {
269     _LIBUNWIND_DEBUG_LOG("__unw_add_dynamic_fde: bad fde: %s", message);
270   }
271 }
272 
273 /// IPI: for __deregister_frame()
274 void __unw_remove_dynamic_fde(unw_word_t fde) {
275   // fde is own mh_group
276   DwarfFDECache<LocalAddressSpace>::removeAllIn((LocalAddressSpace::pint_t)fde);
277 }
278 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
279 #endif // !defined(__USING_SJLJ_EXCEPTIONS__)
280 
281 
282 
283 // Add logging hooks in Debug builds only
284 #ifndef NDEBUG
285 #include <stdlib.h>
286 
287 _LIBUNWIND_HIDDEN
288 bool logAPIs() {
289   // do manual lock to avoid use of _cxa_guard_acquire or initializers
290   static bool checked = false;
291   static bool log = false;
292   if (!checked) {
293     log = (getenv("LIBUNWIND_PRINT_APIS") != NULL);
294     checked = true;
295   }
296   return log;
297 }
298 
299 _LIBUNWIND_HIDDEN
300 bool logUnwinding() {
301   // do manual lock to avoid use of _cxa_guard_acquire or initializers
302   static bool checked = false;
303   static bool log = false;
304   if (!checked) {
305     log = (getenv("LIBUNWIND_PRINT_UNWINDING") != NULL);
306     checked = true;
307   }
308   return log;
309 }
310 
311 _LIBUNWIND_HIDDEN
312 bool logDWARF() {
313   // do manual lock to avoid use of _cxa_guard_acquire or initializers
314   static bool checked = false;
315   static bool log = false;
316   if (!checked) {
317     log = (getenv("LIBUNWIND_PRINT_DWARF") != NULL);
318     checked = true;
319   }
320   return log;
321 }
322 
323 #endif // NDEBUG
324 
325