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