1 //===------------------------- AddressSpace.hpp ---------------------------===//
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
8 // Abstracts accessing local vs remote address spaces.
10 //===----------------------------------------------------------------------===//
12 #ifndef __ADDRESSSPACE_HPP__
13 #define __ADDRESSSPACE_HPP__
20 #ifndef _LIBUNWIND_USE_DLADDR
21 #if !defined(_LIBUNWIND_IS_BAREMETAL) && !defined(_WIN32)
22 #define _LIBUNWIND_USE_DLADDR 1
24 #define _LIBUNWIND_USE_DLADDR 0
28 #if _LIBUNWIND_USE_DLADDR
30 #if defined(__unix__) && defined(__ELF__) && defined(_LIBUNWIND_HAS_COMMENT_LIB_PRAGMA)
31 #pragma comment(lib, "dl")
36 #include <mach-o/getsect.h>
38 bool checkKeyMgrRegisteredFDEs(uintptr_t targetAddr, void *&fde);
42 #include "libunwind.h"
45 #include "EHHeaderParser.hpp"
46 #include "Registers.hpp"
50 struct dyld_unwind_sections
52 const struct mach_header* mh;
53 const void* dwarf_section;
54 uintptr_t dwarf_section_length;
55 const void* compact_unwind_section;
56 uintptr_t compact_unwind_section_length;
58 #if (defined(__MAC_OS_X_VERSION_MIN_REQUIRED) \
59 && (__MAC_OS_X_VERSION_MIN_REQUIRED >= 1070)) \
60 || defined(__IPHONE_OS_VERSION_MIN_REQUIRED)
61 // In 10.7.0 or later, libSystem.dylib implements this function.
62 extern "C" bool _dyld_find_unwind_sections(void *, dyld_unwind_sections *);
64 // In 10.6.x and earlier, we need to implement this functionality. Note
65 // that this requires a newer version of libmacho (from cctools) than is
66 // present in libSystem on 10.6.x (for getsectiondata).
67 static inline bool _dyld_find_unwind_sections(void* addr,
68 dyld_unwind_sections* info) {
69 // Find mach-o image containing address.
71 if (!dladdr(addr, &dlinfo))
74 const struct mach_header_64 *mh = (const struct mach_header_64 *)dlinfo.dli_fbase;
76 const struct mach_header *mh = (const struct mach_header *)dlinfo.dli_fbase;
79 // Initialize the return struct
80 info->mh = (const struct mach_header *)mh;
81 info->dwarf_section = getsectiondata(mh, "__TEXT", "__eh_frame", &info->dwarf_section_length);
82 info->compact_unwind_section = getsectiondata(mh, "__TEXT", "__unwind_info", &info->compact_unwind_section_length);
84 if (!info->dwarf_section) {
85 info->dwarf_section_length = 0;
88 if (!info->compact_unwind_section) {
89 info->compact_unwind_section_length = 0;
96 #elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) && defined(_LIBUNWIND_IS_BAREMETAL)
98 // When statically linked on bare-metal, the symbols for the EH table are looked
99 // up without going through the dynamic loader.
101 // The following linker script may be used to produce the necessary sections and symbols.
102 // Unless the --eh-frame-hdr linker option is provided, the section is not generated
103 // and does not take space in the output file.
107 // __eh_frame_start = .;
108 // KEEP(*(.eh_frame))
109 // __eh_frame_end = .;
114 // KEEP(*(.eh_frame_hdr))
117 // __eh_frame_hdr_start = SIZEOF(.eh_frame_hdr) > 0 ? ADDR(.eh_frame_hdr) : 0;
118 // __eh_frame_hdr_end = SIZEOF(.eh_frame_hdr) > 0 ? . : 0;
120 extern char __eh_frame_start;
121 extern char __eh_frame_end;
123 #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
124 extern char __eh_frame_hdr_start;
125 extern char __eh_frame_hdr_end;
128 #elif defined(_LIBUNWIND_ARM_EHABI) && defined(_LIBUNWIND_IS_BAREMETAL)
130 // When statically linked on bare-metal, the symbols for the EH table are looked
131 // up without going through the dynamic loader.
132 extern char __exidx_start;
133 extern char __exidx_end;
135 #elif defined(_LIBUNWIND_ARM_EHABI) || defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
137 // ELF-based systems may use dl_iterate_phdr() to access sections
138 // containing unwinding information. The ElfW() macro for pointer-size
139 // independent ELF header traversal is not provided by <link.h> on some
140 // systems (e.g., FreeBSD). On these systems the data structures are
141 // just called Elf_XXX. Define ElfW() locally.
149 #define ElfW(type) Elf_##type
154 namespace libunwind {
156 /// Used by findUnwindSections() to return info about needed sections.
157 struct UnwindInfoSections {
158 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) || defined(_LIBUNWIND_SUPPORT_DWARF_INDEX) || \
159 defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
160 // No dso_base for SEH or ARM EHABI.
163 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
164 uintptr_t dwarf_section;
165 uintptr_t dwarf_section_length;
167 #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
168 uintptr_t dwarf_index_section;
169 uintptr_t dwarf_index_section_length;
171 #if defined(_LIBUNWIND_SUPPORT_COMPACT_UNWIND)
172 uintptr_t compact_unwind_section;
173 uintptr_t compact_unwind_section_length;
175 #if defined(_LIBUNWIND_ARM_EHABI)
176 uintptr_t arm_section;
177 uintptr_t arm_section_length;
182 /// LocalAddressSpace is used as a template parameter to UnwindCursor when
183 /// unwinding a thread in the same process. The wrappers compile away,
184 /// making local unwinds fast.
185 class _LIBUNWIND_HIDDEN LocalAddressSpace {
187 typedef uintptr_t pint_t;
188 typedef intptr_t sint_t;
189 uint8_t get8(pint_t addr) {
191 memcpy(&val, (void *)addr, sizeof(val));
194 uint16_t get16(pint_t addr) {
196 memcpy(&val, (void *)addr, sizeof(val));
199 uint32_t get32(pint_t addr) {
201 memcpy(&val, (void *)addr, sizeof(val));
204 uint64_t get64(pint_t addr) {
206 memcpy(&val, (void *)addr, sizeof(val));
209 double getDouble(pint_t addr) {
211 memcpy(&val, (void *)addr, sizeof(val));
214 v128 getVector(pint_t addr) {
216 memcpy(&val, (void *)addr, sizeof(val));
219 uintptr_t getP(pint_t addr);
220 uint64_t getRegister(pint_t addr);
221 static uint64_t getULEB128(pint_t &addr, pint_t end);
222 static int64_t getSLEB128(pint_t &addr, pint_t end);
224 pint_t getEncodedP(pint_t &addr, pint_t end, uint8_t encoding,
225 pint_t datarelBase = 0);
226 bool findFunctionName(pint_t addr, char *buf, size_t bufLen,
228 bool findUnwindSections(pint_t targetAddr, UnwindInfoSections &info);
229 bool findOtherFDE(pint_t targetAddr, pint_t &fde);
231 static LocalAddressSpace sThisAddressSpace;
234 inline uintptr_t LocalAddressSpace::getP(pint_t addr) {
235 #if __SIZEOF_POINTER__ == 8
242 inline uint64_t LocalAddressSpace::getRegister(pint_t addr) {
243 #if __SIZEOF_POINTER__ == 8 || defined(__mips64)
250 /// Read a ULEB128 into a 64-bit word.
251 inline uint64_t LocalAddressSpace::getULEB128(pint_t &addr, pint_t end) {
252 const uint8_t *p = (uint8_t *)addr;
253 const uint8_t *pend = (uint8_t *)end;
260 _LIBUNWIND_ABORT("truncated uleb128 expression");
264 if (bit >= 64 || b << bit >> bit != b) {
265 _LIBUNWIND_ABORT("malformed uleb128 expression");
270 } while (*p++ >= 0x80);
275 /// Read a SLEB128 into a 64-bit word.
276 inline int64_t LocalAddressSpace::getSLEB128(pint_t &addr, pint_t end) {
277 const uint8_t *p = (uint8_t *)addr;
278 const uint8_t *pend = (uint8_t *)end;
284 _LIBUNWIND_ABORT("truncated sleb128 expression");
286 result |= ((byte & 0x7f) << bit);
288 } while (byte & 0x80);
289 // sign extend negative numbers
290 if ((byte & 0x40) != 0)
291 result |= (-1ULL) << bit;
296 inline LocalAddressSpace::pint_t
297 LocalAddressSpace::getEncodedP(pint_t &addr, pint_t end, uint8_t encoding,
298 pint_t datarelBase) {
299 pint_t startAddr = addr;
300 const uint8_t *p = (uint8_t *)addr;
304 switch (encoding & 0x0F) {
310 case DW_EH_PE_uleb128:
311 result = (pint_t)getULEB128(addr, end);
313 case DW_EH_PE_udata2:
314 result = get16(addr);
318 case DW_EH_PE_udata4:
319 result = get32(addr);
323 case DW_EH_PE_udata8:
324 result = (pint_t)get64(addr);
328 case DW_EH_PE_sleb128:
329 result = (pint_t)getSLEB128(addr, end);
331 case DW_EH_PE_sdata2:
332 // Sign extend from signed 16-bit value.
333 result = (pint_t)(int16_t)get16(addr);
337 case DW_EH_PE_sdata4:
338 // Sign extend from signed 32-bit value.
339 result = (pint_t)(int32_t)get32(addr);
343 case DW_EH_PE_sdata8:
344 result = (pint_t)get64(addr);
349 _LIBUNWIND_ABORT("unknown pointer encoding");
352 // then add relative offset
353 switch (encoding & 0x70) {
354 case DW_EH_PE_absptr:
360 case DW_EH_PE_textrel:
361 _LIBUNWIND_ABORT("DW_EH_PE_textrel pointer encoding not supported");
363 case DW_EH_PE_datarel:
364 // DW_EH_PE_datarel is only valid in a few places, so the parameter has a
365 // default value of 0, and we abort in the event that someone calls this
366 // function with a datarelBase of 0 and DW_EH_PE_datarel encoding.
367 if (datarelBase == 0)
368 _LIBUNWIND_ABORT("DW_EH_PE_datarel is invalid with a datarelBase of 0");
369 result += datarelBase;
371 case DW_EH_PE_funcrel:
372 _LIBUNWIND_ABORT("DW_EH_PE_funcrel pointer encoding not supported");
374 case DW_EH_PE_aligned:
375 _LIBUNWIND_ABORT("DW_EH_PE_aligned pointer encoding not supported");
378 _LIBUNWIND_ABORT("unknown pointer encoding");
382 if (encoding & DW_EH_PE_indirect)
383 result = getP(result);
388 inline bool LocalAddressSpace::findUnwindSections(pint_t targetAddr,
389 UnwindInfoSections &info) {
391 dyld_unwind_sections dyldInfo;
392 if (_dyld_find_unwind_sections((void *)targetAddr, &dyldInfo)) {
393 info.dso_base = (uintptr_t)dyldInfo.mh;
394 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
395 info.dwarf_section = (uintptr_t)dyldInfo.dwarf_section;
396 info.dwarf_section_length = dyldInfo.dwarf_section_length;
398 info.compact_unwind_section = (uintptr_t)dyldInfo.compact_unwind_section;
399 info.compact_unwind_section_length = dyldInfo.compact_unwind_section_length;
402 #elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) && defined(_LIBUNWIND_IS_BAREMETAL)
403 // Bare metal is statically linked, so no need to ask the dynamic loader
404 info.dwarf_section_length = (uintptr_t)(&__eh_frame_end - &__eh_frame_start);
405 info.dwarf_section = (uintptr_t)(&__eh_frame_start);
406 _LIBUNWIND_TRACE_UNWINDING("findUnwindSections: section %p length %p",
407 (void *)info.dwarf_section, (void *)info.dwarf_section_length);
408 #if defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
409 info.dwarf_index_section = (uintptr_t)(&__eh_frame_hdr_start);
410 info.dwarf_index_section_length = (uintptr_t)(&__eh_frame_hdr_end - &__eh_frame_hdr_start);
411 _LIBUNWIND_TRACE_UNWINDING("findUnwindSections: index section %p length %p",
412 (void *)info.dwarf_index_section, (void *)info.dwarf_index_section_length);
414 if (info.dwarf_section_length)
416 #elif defined(_LIBUNWIND_ARM_EHABI) && defined(_LIBUNWIND_IS_BAREMETAL)
417 // Bare metal is statically linked, so no need to ask the dynamic loader
418 info.arm_section = (uintptr_t)(&__exidx_start);
419 info.arm_section_length = (uintptr_t)(&__exidx_end - &__exidx_start);
420 _LIBUNWIND_TRACE_UNWINDING("findUnwindSections: section %p length %p",
421 (void *)info.arm_section, (void *)info.arm_section_length);
422 if (info.arm_section && info.arm_section_length)
424 #elif defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND) && defined(_WIN32)
426 HANDLE process = GetCurrentProcess();
429 if (!EnumProcessModules(process, mods, sizeof(mods), &needed))
432 for (unsigned i = 0; i < (needed / sizeof(HMODULE)); i++) {
433 PIMAGE_DOS_HEADER pidh = (PIMAGE_DOS_HEADER)mods[i];
434 PIMAGE_NT_HEADERS pinh = (PIMAGE_NT_HEADERS)((BYTE *)pidh + pidh->e_lfanew);
435 PIMAGE_FILE_HEADER pifh = (PIMAGE_FILE_HEADER)&pinh->FileHeader;
436 PIMAGE_SECTION_HEADER pish = IMAGE_FIRST_SECTION(pinh);
437 bool found_obj = false;
438 bool found_hdr = false;
440 info.dso_base = (uintptr_t)mods[i];
441 for (unsigned j = 0; j < pifh->NumberOfSections; j++, pish++) {
442 uintptr_t begin = pish->VirtualAddress + (uintptr_t)mods[i];
443 uintptr_t end = begin + pish->Misc.VirtualSize;
444 if (!strncmp((const char *)pish->Name, ".text",
445 IMAGE_SIZEOF_SHORT_NAME)) {
446 if (targetAddr >= begin && targetAddr < end)
448 } else if (!strncmp((const char *)pish->Name, ".eh_frame",
449 IMAGE_SIZEOF_SHORT_NAME)) {
450 info.dwarf_section = begin;
451 info.dwarf_section_length = pish->Misc.VirtualSize;
454 if (found_obj && found_hdr)
459 #elif defined(_LIBUNWIND_SUPPORT_SEH_UNWIND) && defined(_WIN32)
460 // Don't even bother, since Windows has functions that do all this stuff
465 #elif defined(_LIBUNWIND_ARM_EHABI) && defined(__BIONIC__) && \
466 (__ANDROID_API__ < 21)
469 (uintptr_t)dl_unwind_find_exidx((_Unwind_Ptr)targetAddr, &length);
470 info.arm_section_length = (uintptr_t)length;
471 if (info.arm_section && info.arm_section_length)
473 #elif defined(_LIBUNWIND_ARM_EHABI) || defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
474 struct dl_iterate_cb_data {
475 LocalAddressSpace *addressSpace;
476 UnwindInfoSections *sects;
477 uintptr_t targetAddr;
480 dl_iterate_cb_data cb_data = {this, &info, targetAddr};
481 int found = dl_iterate_phdr(
482 [](struct dl_phdr_info *pinfo, size_t, void *data) -> int {
483 auto cbdata = static_cast<dl_iterate_cb_data *>(data);
484 bool found_obj = false;
485 bool found_hdr = false;
488 assert(cbdata->sects);
490 if (cbdata->targetAddr < pinfo->dlpi_addr) {
494 #if !defined(Elf_Half)
495 typedef ElfW(Half) Elf_Half;
497 #if !defined(Elf_Phdr)
498 typedef ElfW(Phdr) Elf_Phdr;
500 #if !defined(Elf_Addr) && defined(__ANDROID__)
501 typedef ElfW(Addr) Elf_Addr;
504 #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
505 #if !defined(_LIBUNWIND_SUPPORT_DWARF_INDEX)
506 #error "_LIBUNWIND_SUPPORT_DWARF_UNWIND requires _LIBUNWIND_SUPPORT_DWARF_INDEX on this platform."
508 size_t object_length;
509 #if defined(__ANDROID__)
510 Elf_Addr image_base =
512 ? reinterpret_cast<Elf_Addr>(pinfo->dlpi_phdr) -
513 reinterpret_cast<const Elf_Phdr *>(pinfo->dlpi_phdr)
518 for (Elf_Half i = 0; i < pinfo->dlpi_phnum; i++) {
519 const Elf_Phdr *phdr = &pinfo->dlpi_phdr[i];
520 if (phdr->p_type == PT_LOAD) {
521 uintptr_t begin = pinfo->dlpi_addr + phdr->p_vaddr;
522 #if defined(__ANDROID__)
523 if (pinfo->dlpi_addr == 0 && phdr->p_vaddr < image_base)
524 begin = begin + image_base;
526 uintptr_t end = begin + phdr->p_memsz;
527 if (cbdata->targetAddr >= begin && cbdata->targetAddr < end) {
528 cbdata->sects->dso_base = begin;
529 object_length = phdr->p_memsz;
532 } else if (phdr->p_type == PT_GNU_EH_FRAME) {
533 EHHeaderParser<LocalAddressSpace>::EHHeaderInfo hdrInfo;
534 uintptr_t eh_frame_hdr_start = pinfo->dlpi_addr + phdr->p_vaddr;
535 #if defined(__ANDROID__)
536 if (pinfo->dlpi_addr == 0 && phdr->p_vaddr < image_base)
537 eh_frame_hdr_start = eh_frame_hdr_start + image_base;
539 cbdata->sects->dwarf_index_section = eh_frame_hdr_start;
540 cbdata->sects->dwarf_index_section_length = phdr->p_memsz;
541 found_hdr = EHHeaderParser<LocalAddressSpace>::decodeEHHdr(
542 *cbdata->addressSpace, eh_frame_hdr_start, phdr->p_memsz,
545 cbdata->sects->dwarf_section = hdrInfo.eh_frame_ptr;
549 if (found_obj && found_hdr) {
550 cbdata->sects->dwarf_section_length = object_length;
555 #else // defined(_LIBUNWIND_ARM_EHABI)
556 for (Elf_Half i = 0; i < pinfo->dlpi_phnum; i++) {
557 const Elf_Phdr *phdr = &pinfo->dlpi_phdr[i];
558 if (phdr->p_type == PT_LOAD) {
559 uintptr_t begin = pinfo->dlpi_addr + phdr->p_vaddr;
560 uintptr_t end = begin + phdr->p_memsz;
561 if (cbdata->targetAddr >= begin && cbdata->targetAddr < end)
563 } else if (phdr->p_type == PT_ARM_EXIDX) {
564 uintptr_t exidx_start = pinfo->dlpi_addr + phdr->p_vaddr;
565 cbdata->sects->arm_section = exidx_start;
566 cbdata->sects->arm_section_length = phdr->p_memsz;
570 return found_obj && found_hdr;
574 return static_cast<bool>(found);
581 inline bool LocalAddressSpace::findOtherFDE(pint_t targetAddr, pint_t &fde) {
583 return checkKeyMgrRegisteredFDEs(targetAddr, *((void**)&fde));
585 // TO DO: if OS has way to dynamically register FDEs, check that.
592 inline bool LocalAddressSpace::findFunctionName(pint_t addr, char *buf,
594 unw_word_t *offset) {
595 #if _LIBUNWIND_USE_DLADDR
597 if (dladdr((void *)addr, &dyldInfo)) {
598 if (dyldInfo.dli_sname != NULL) {
599 snprintf(buf, bufLen, "%s", dyldInfo.dli_sname);
600 *offset = (addr - (pint_t) dyldInfo.dli_saddr);
613 } // namespace libunwind
615 #endif // __ADDRESSSPACE_HPP__