1 //===----------------------------------------------------------------------===//
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 "config.h"
15 #include "libunwind_ext.h"
16 
17 #include <stdlib.h>
18 
19 // Define the __has_feature extension for compilers that do not support it so
20 // that we can later check for the presence of ASan in a compiler-neutral way.
21 #if !defined(__has_feature)
22 #define __has_feature(feature) 0
23 #endif
24 
25 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
26 #include <sanitizer/asan_interface.h>
27 #endif
28 
29 #if !defined(__USING_SJLJ_EXCEPTIONS__)
30 #include "AddressSpace.hpp"
31 #include "UnwindCursor.hpp"
32 
33 using namespace libunwind;
34 
35 /// internal object to represent this processes address space
36 LocalAddressSpace LocalAddressSpace::sThisAddressSpace;
37 
38 _LIBUNWIND_EXPORT unw_addr_space_t unw_local_addr_space =
39     (unw_addr_space_t)&LocalAddressSpace::sThisAddressSpace;
40 
41 /// Create a cursor of a thread in this process given 'context' recorded by
42 /// __unw_getcontext().
43 _LIBUNWIND_HIDDEN int __unw_init_local(unw_cursor_t *cursor,
44                                        unw_context_t *context) {
45   _LIBUNWIND_TRACE_API("__unw_init_local(cursor=%p, context=%p)",
46                        static_cast<void *>(cursor),
47                        static_cast<void *>(context));
48 #if defined(__i386__)
49 # define REGISTER_KIND Registers_x86
50 #elif defined(__x86_64__)
51 # define REGISTER_KIND Registers_x86_64
52 #elif defined(__powerpc64__)
53 # define REGISTER_KIND Registers_ppc64
54 #elif defined(__powerpc__)
55 # define REGISTER_KIND Registers_ppc
56 #elif defined(__aarch64__)
57 # define REGISTER_KIND Registers_arm64
58 #elif defined(__arm__)
59 # define REGISTER_KIND Registers_arm
60 #elif defined(__or1k__)
61 # define REGISTER_KIND Registers_or1k
62 #elif defined(__hexagon__)
63 # define REGISTER_KIND Registers_hexagon
64 #elif defined(__mips__) && defined(_ABIO32) && _MIPS_SIM == _ABIO32
65 # define REGISTER_KIND Registers_mips_o32
66 #elif defined(__mips64)
67 # define REGISTER_KIND Registers_mips_newabi
68 #elif defined(__mips__)
69 # warning The MIPS architecture is not supported with this ABI and environment!
70 #elif defined(__sparc__) && defined(__arch64__)
71 #define REGISTER_KIND Registers_sparc64
72 #elif defined(__sparc__)
73 # define REGISTER_KIND Registers_sparc
74 #elif defined(__riscv)
75 # define REGISTER_KIND Registers_riscv
76 #elif defined(__ve__)
77 # define REGISTER_KIND Registers_ve
78 #elif defined(__s390x__)
79 # define REGISTER_KIND Registers_s390x
80 #else
81 # error Architecture not supported
82 #endif
83   // Use "placement new" to allocate UnwindCursor in the cursor buffer.
84   new (reinterpret_cast<UnwindCursor<LocalAddressSpace, REGISTER_KIND> *>(cursor))
85       UnwindCursor<LocalAddressSpace, REGISTER_KIND>(
86           context, LocalAddressSpace::sThisAddressSpace);
87 #undef REGISTER_KIND
88   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
89   co->setInfoBasedOnIPRegister();
90 
91   return UNW_ESUCCESS;
92 }
93 _LIBUNWIND_WEAK_ALIAS(__unw_init_local, unw_init_local)
94 
95 /// Get value of specified register at cursor position in stack frame.
96 _LIBUNWIND_HIDDEN int __unw_get_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
97                                     unw_word_t *value) {
98   _LIBUNWIND_TRACE_API("__unw_get_reg(cursor=%p, regNum=%d, &value=%p)",
99                        static_cast<void *>(cursor), regNum,
100                        static_cast<void *>(value));
101   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
102   if (co->validReg(regNum)) {
103     *value = co->getReg(regNum);
104     return UNW_ESUCCESS;
105   }
106   return UNW_EBADREG;
107 }
108 _LIBUNWIND_WEAK_ALIAS(__unw_get_reg, unw_get_reg)
109 
110 /// Set value of specified register at cursor position in stack frame.
111 _LIBUNWIND_HIDDEN int __unw_set_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
112                                     unw_word_t value) {
113   _LIBUNWIND_TRACE_API("__unw_set_reg(cursor=%p, regNum=%d, value=0x%" PRIxPTR
114                        ")",
115                        static_cast<void *>(cursor), regNum, value);
116   typedef LocalAddressSpace::pint_t pint_t;
117   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
118   if (co->validReg(regNum)) {
119     co->setReg(regNum, (pint_t)value);
120     // specical case altering IP to re-find info (being called by personality
121     // function)
122     if (regNum == UNW_REG_IP) {
123       unw_proc_info_t info;
124       // First, get the FDE for the old location and then update it.
125       co->getInfo(&info);
126       co->setInfoBasedOnIPRegister(false);
127       // If the original call expects stack adjustment, perform this now.
128       // Normal frame unwinding would have included the offset already in the
129       // CFA computation.
130       // Note: for PA-RISC and other platforms where the stack grows up,
131       // this should actually be - info.gp. LLVM doesn't currently support
132       // any such platforms and Clang doesn't export a macro for them.
133       if (info.gp)
134         co->setReg(UNW_REG_SP, co->getReg(UNW_REG_SP) + info.gp);
135     }
136     return UNW_ESUCCESS;
137   }
138   return UNW_EBADREG;
139 }
140 _LIBUNWIND_WEAK_ALIAS(__unw_set_reg, unw_set_reg)
141 
142 /// Get value of specified float register at cursor position in stack frame.
143 _LIBUNWIND_HIDDEN int __unw_get_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
144                                       unw_fpreg_t *value) {
145   _LIBUNWIND_TRACE_API("__unw_get_fpreg(cursor=%p, regNum=%d, &value=%p)",
146                        static_cast<void *>(cursor), regNum,
147                        static_cast<void *>(value));
148   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
149   if (co->validFloatReg(regNum)) {
150     *value = co->getFloatReg(regNum);
151     return UNW_ESUCCESS;
152   }
153   return UNW_EBADREG;
154 }
155 _LIBUNWIND_WEAK_ALIAS(__unw_get_fpreg, unw_get_fpreg)
156 
157 /// Set value of specified float register at cursor position in stack frame.
158 _LIBUNWIND_HIDDEN int __unw_set_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
159                                       unw_fpreg_t value) {
160 #if defined(_LIBUNWIND_ARM_EHABI)
161   _LIBUNWIND_TRACE_API("__unw_set_fpreg(cursor=%p, regNum=%d, value=%llX)",
162                        static_cast<void *>(cursor), regNum, value);
163 #else
164   _LIBUNWIND_TRACE_API("__unw_set_fpreg(cursor=%p, regNum=%d, value=%g)",
165                        static_cast<void *>(cursor), regNum, value);
166 #endif
167   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
168   if (co->validFloatReg(regNum)) {
169     co->setFloatReg(regNum, value);
170     return UNW_ESUCCESS;
171   }
172   return UNW_EBADREG;
173 }
174 _LIBUNWIND_WEAK_ALIAS(__unw_set_fpreg, unw_set_fpreg)
175 
176 /// Move cursor to next frame.
177 _LIBUNWIND_HIDDEN int __unw_step(unw_cursor_t *cursor) {
178   _LIBUNWIND_TRACE_API("__unw_step(cursor=%p)", static_cast<void *>(cursor));
179   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
180   return co->step();
181 }
182 _LIBUNWIND_WEAK_ALIAS(__unw_step, unw_step)
183 
184 /// Get unwind info at cursor position in stack frame.
185 _LIBUNWIND_HIDDEN int __unw_get_proc_info(unw_cursor_t *cursor,
186                                           unw_proc_info_t *info) {
187   _LIBUNWIND_TRACE_API("__unw_get_proc_info(cursor=%p, &info=%p)",
188                        static_cast<void *>(cursor), static_cast<void *>(info));
189   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
190   co->getInfo(info);
191   if (info->end_ip == 0)
192     return UNW_ENOINFO;
193   return UNW_ESUCCESS;
194 }
195 _LIBUNWIND_WEAK_ALIAS(__unw_get_proc_info, unw_get_proc_info)
196 
197 /// Resume execution at cursor position (aka longjump).
198 _LIBUNWIND_HIDDEN int __unw_resume(unw_cursor_t *cursor) {
199   _LIBUNWIND_TRACE_API("__unw_resume(cursor=%p)", static_cast<void *>(cursor));
200 #if __has_feature(address_sanitizer) || defined(__SANITIZE_ADDRESS__)
201   // Inform the ASan runtime that now might be a good time to clean stuff up.
202   __asan_handle_no_return();
203 #endif
204   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
205   co->jumpto();
206   return UNW_EUNSPEC;
207 }
208 _LIBUNWIND_WEAK_ALIAS(__unw_resume, unw_resume)
209 
210 /// Get name of function at cursor position in stack frame.
211 _LIBUNWIND_HIDDEN int __unw_get_proc_name(unw_cursor_t *cursor, char *buf,
212                                           size_t bufLen, unw_word_t *offset) {
213   _LIBUNWIND_TRACE_API("__unw_get_proc_name(cursor=%p, &buf=%p, bufLen=%lu)",
214                        static_cast<void *>(cursor), static_cast<void *>(buf),
215                        static_cast<unsigned long>(bufLen));
216   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
217   if (co->getFunctionName(buf, bufLen, offset))
218     return UNW_ESUCCESS;
219   return UNW_EUNSPEC;
220 }
221 _LIBUNWIND_WEAK_ALIAS(__unw_get_proc_name, unw_get_proc_name)
222 
223 /// Checks if a register is a floating-point register.
224 _LIBUNWIND_HIDDEN int __unw_is_fpreg(unw_cursor_t *cursor,
225                                      unw_regnum_t regNum) {
226   _LIBUNWIND_TRACE_API("__unw_is_fpreg(cursor=%p, regNum=%d)",
227                        static_cast<void *>(cursor), regNum);
228   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
229   return co->validFloatReg(regNum);
230 }
231 _LIBUNWIND_WEAK_ALIAS(__unw_is_fpreg, unw_is_fpreg)
232 
233 /// Checks if a register is a floating-point register.
234 _LIBUNWIND_HIDDEN const char *__unw_regname(unw_cursor_t *cursor,
235                                             unw_regnum_t regNum) {
236   _LIBUNWIND_TRACE_API("__unw_regname(cursor=%p, regNum=%d)",
237                        static_cast<void *>(cursor), regNum);
238   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
239   return co->getRegisterName(regNum);
240 }
241 _LIBUNWIND_WEAK_ALIAS(__unw_regname, unw_regname)
242 
243 /// Checks if current frame is signal trampoline.
244 _LIBUNWIND_HIDDEN int __unw_is_signal_frame(unw_cursor_t *cursor) {
245   _LIBUNWIND_TRACE_API("__unw_is_signal_frame(cursor=%p)",
246                        static_cast<void *>(cursor));
247   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
248   return co->isSignalFrame();
249 }
250 _LIBUNWIND_WEAK_ALIAS(__unw_is_signal_frame, unw_is_signal_frame)
251 
252 #ifdef _AIX
253 _LIBUNWIND_EXPORT uintptr_t __unw_get_data_rel_base(unw_cursor_t *cursor) {
254   _LIBUNWIND_TRACE_API("unw_get_data_rel_base(cursor=%p)",
255                        static_cast<void *>(cursor));
256   AbstractUnwindCursor *co = reinterpret_cast<AbstractUnwindCursor *>(cursor);
257   return co->getDataRelBase();
258 }
259 _LIBUNWIND_WEAK_ALIAS(__unw_get_data_rel_base, unw_get_data_rel_base)
260 #endif
261 
262 #ifdef __arm__
263 // Save VFP registers d0-d15 using FSTMIADX instead of FSTMIADD
264 _LIBUNWIND_HIDDEN void __unw_save_vfp_as_X(unw_cursor_t *cursor) {
265   _LIBUNWIND_TRACE_API("__unw_get_fpreg_save_vfp_as_X(cursor=%p)",
266                        static_cast<void *>(cursor));
267   AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
268   return co->saveVFPAsX();
269 }
270 _LIBUNWIND_WEAK_ALIAS(__unw_save_vfp_as_X, unw_save_vfp_as_X)
271 #endif
272 
273 
274 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
275 /// SPI: walks cached DWARF entries
276 _LIBUNWIND_HIDDEN void __unw_iterate_dwarf_unwind_cache(void (*func)(
277     unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
278   _LIBUNWIND_TRACE_API("__unw_iterate_dwarf_unwind_cache(func=%p)",
279                        reinterpret_cast<void *>(func));
280   DwarfFDECache<LocalAddressSpace>::iterateCacheEntries(func);
281 }
282 _LIBUNWIND_WEAK_ALIAS(__unw_iterate_dwarf_unwind_cache,
283                       unw_iterate_dwarf_unwind_cache)
284 
285 /// IPI: for __register_frame()
286 void __unw_add_dynamic_fde(unw_word_t fde) {
287   CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
288   CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
289   const char *message = CFI_Parser<LocalAddressSpace>::decodeFDE(
290                            LocalAddressSpace::sThisAddressSpace,
291                           (LocalAddressSpace::pint_t) fde, &fdeInfo, &cieInfo);
292   if (message == NULL) {
293     // dynamically registered FDEs don't have a mach_header group they are in.
294     // Use fde as mh_group
295     unw_word_t mh_group = fdeInfo.fdeStart;
296     DwarfFDECache<LocalAddressSpace>::add((LocalAddressSpace::pint_t)mh_group,
297                                           fdeInfo.pcStart, fdeInfo.pcEnd,
298                                           fdeInfo.fdeStart);
299   } else {
300     _LIBUNWIND_DEBUG_LOG("__unw_add_dynamic_fde: bad fde: %s", message);
301   }
302 }
303 
304 /// IPI: for __deregister_frame()
305 void __unw_remove_dynamic_fde(unw_word_t fde) {
306   // fde is own mh_group
307   DwarfFDECache<LocalAddressSpace>::removeAllIn((LocalAddressSpace::pint_t)fde);
308 }
309 
310 void __unw_add_dynamic_eh_frame_section(unw_word_t eh_frame_start) {
311   // The eh_frame section start serves as the mh_group
312   unw_word_t mh_group = eh_frame_start;
313   CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
314   CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
315   auto p = (LocalAddressSpace::pint_t)eh_frame_start;
316   while (true) {
317     if (CFI_Parser<LocalAddressSpace>::decodeFDE(
318             LocalAddressSpace::sThisAddressSpace, p, &fdeInfo, &cieInfo,
319             true) == NULL) {
320       DwarfFDECache<LocalAddressSpace>::add((LocalAddressSpace::pint_t)mh_group,
321                                             fdeInfo.pcStart, fdeInfo.pcEnd,
322                                             fdeInfo.fdeStart);
323       p += fdeInfo.fdeLength;
324     } else if (CFI_Parser<LocalAddressSpace>::parseCIE(
325                    LocalAddressSpace::sThisAddressSpace, p, &cieInfo) == NULL) {
326       p += cieInfo.cieLength;
327     } else
328       return;
329   }
330 }
331 
332 void __unw_remove_dynamic_eh_frame_section(unw_word_t eh_frame_start) {
333   // The eh_frame section start serves as the mh_group
334   DwarfFDECache<LocalAddressSpace>::removeAllIn(
335       (LocalAddressSpace::pint_t)eh_frame_start);
336 }
337 
338 #endif // defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
339 #endif // !defined(__USING_SJLJ_EXCEPTIONS__)
340 
341 
342 
343 // Add logging hooks in Debug builds only
344 #ifndef NDEBUG
345 #include <stdlib.h>
346 
347 _LIBUNWIND_HIDDEN
348 bool logAPIs() {
349   // do manual lock to avoid use of _cxa_guard_acquire or initializers
350   static bool checked = false;
351   static bool log = false;
352   if (!checked) {
353     log = (getenv("LIBUNWIND_PRINT_APIS") != NULL);
354     checked = true;
355   }
356   return log;
357 }
358 
359 _LIBUNWIND_HIDDEN
360 bool logUnwinding() {
361   // do manual lock to avoid use of _cxa_guard_acquire or initializers
362   static bool checked = false;
363   static bool log = false;
364   if (!checked) {
365     log = (getenv("LIBUNWIND_PRINT_UNWINDING") != NULL);
366     checked = true;
367   }
368   return log;
369 }
370 
371 _LIBUNWIND_HIDDEN
372 bool logDWARF() {
373   // do manual lock to avoid use of _cxa_guard_acquire or initializers
374   static bool checked = false;
375   static bool log = false;
376   if (!checked) {
377     log = (getenv("LIBUNWIND_PRINT_DWARF") != NULL);
378     checked = true;
379   }
380   return log;
381 }
382 
383 #endif // NDEBUG
384 
385