diff options
Diffstat (limited to 'abseil-cpp/absl/debugging/symbolize_elf.inc')
| -rw-r--r-- | abseil-cpp/absl/debugging/symbolize_elf.inc | 337 |
1 files changed, 219 insertions, 118 deletions
diff --git a/abseil-cpp/absl/debugging/symbolize_elf.inc b/abseil-cpp/absl/debugging/symbolize_elf.inc index 7c36fd1..30638cb 100644 --- a/abseil-cpp/absl/debugging/symbolize_elf.inc +++ b/abseil-cpp/absl/debugging/symbolize_elf.inc @@ -77,6 +77,10 @@ #include "absl/debugging/internal/vdso_support.h" #include "absl/strings/string_view.h" +#if defined(__FreeBSD__) && !defined(ElfW) +#define ElfW(x) __ElfN(x) +#endif + namespace absl { ABSL_NAMESPACE_BEGIN @@ -201,7 +205,8 @@ struct ObjFile { // PT_LOAD program header describing executable code. // Normally we expect just one, but SWIFT binaries have two. - std::array<ElfW(Phdr), 2> phdr; + // CUDA binaries have 3 (see cr/473913254 description). + std::array<ElfW(Phdr), 4> phdr; }; // Build 4-way associative cache for symbols. Within each cache line, symbols @@ -248,21 +253,21 @@ class AddrMap { public: AddrMap() : size_(0), allocated_(0), obj_(nullptr) {} ~AddrMap() { base_internal::LowLevelAlloc::Free(obj_); } - int Size() const { return size_; } - ObjFile *At(int i) { return &obj_[i]; } + size_t Size() const { return size_; } + ObjFile *At(size_t i) { return &obj_[i]; } ObjFile *Add(); void Clear(); private: - int size_; // count of valid elements (<= allocated_) - int allocated_; // count of allocated elements - ObjFile *obj_; // array of allocated_ elements + size_t size_; // count of valid elements (<= allocated_) + size_t allocated_; // count of allocated elements + ObjFile *obj_; // array of allocated_ elements AddrMap(const AddrMap &) = delete; AddrMap &operator=(const AddrMap &) = delete; }; void AddrMap::Clear() { - for (int i = 0; i != size_; i++) { + for (size_t i = 0; i != size_; i++) { At(i)->~ObjFile(); } size_ = 0; @@ -270,7 +275,7 @@ void AddrMap::Clear() { ObjFile *AddrMap::Add() { if (size_ == allocated_) { - int new_allocated = allocated_ * 2 + 50; + size_t new_allocated = allocated_ * 2 + 50; ObjFile *new_obj_ = static_cast<ObjFile *>(base_internal::LowLevelAlloc::AllocWithArena( new_allocated * sizeof(*new_obj_), SigSafeArena())); @@ -296,7 +301,7 @@ class Symbolizer { private: char *CopyString(const char *s) { - int len = strlen(s); + size_t len = strlen(s); char *dst = static_cast<char *>( base_internal::LowLevelAlloc::AllocWithArena(len + 1, SigSafeArena())); ABSL_RAW_CHECK(dst != nullptr, "out of memory"); @@ -317,8 +322,9 @@ class Symbolizer { FindSymbolResult GetSymbolFromObjectFile(const ObjFile &obj, const void *const pc, const ptrdiff_t relocation, - char *out, int out_size, - char *tmp_buf, int tmp_buf_size); + char *out, size_t out_size, + char *tmp_buf, size_t tmp_buf_size); + const char *GetUncachedSymbol(const void *pc); enum { SYMBOL_BUF_SIZE = 3072, @@ -348,11 +354,11 @@ static std::atomic<Symbolizer *> g_cached_symbolizer; } // namespace -static int SymbolizerSize() { +static size_t SymbolizerSize() { #if defined(__wasm__) || defined(__asmjs__) - int pagesize = getpagesize(); + auto pagesize = static_cast<size_t>(getpagesize()); #else - int pagesize = sysconf(_SC_PAGESIZE); + auto pagesize = static_cast<size_t>(sysconf(_SC_PAGESIZE)); #endif return ((sizeof(Symbolizer) - 1) / pagesize + 1) * pagesize; } @@ -424,7 +430,7 @@ static ssize_t ReadPersistent(int fd, void *buf, size_t count) { if (len == 0) { // Reached EOF. break; } - num_bytes += len; + num_bytes += static_cast<size_t>(len); } SAFE_ASSERT(num_bytes <= count); return static_cast<ssize_t>(num_bytes); @@ -437,8 +443,8 @@ static ssize_t ReadFromOffset(const int fd, void *buf, const size_t count, const off_t offset) { off_t off = lseek(fd, offset, SEEK_SET); if (off == (off_t)-1) { - ABSL_RAW_LOG(WARNING, "lseek(%d, %ju, SEEK_SET) failed: errno=%d", fd, - static_cast<uintmax_t>(offset), errno); + ABSL_RAW_LOG(WARNING, "lseek(%d, %jd, SEEK_SET) failed: errno=%d", fd, + static_cast<intmax_t>(offset), errno); return -1; } return ReadPersistent(fd, buf, count); @@ -473,29 +479,37 @@ static int FileGetElfType(const int fd) { // inlined. static ABSL_ATTRIBUTE_NOINLINE bool GetSectionHeaderByType( const int fd, ElfW(Half) sh_num, const off_t sh_offset, ElfW(Word) type, - ElfW(Shdr) * out, char *tmp_buf, int tmp_buf_size) { + ElfW(Shdr) * out, char *tmp_buf, size_t tmp_buf_size) { ElfW(Shdr) *buf = reinterpret_cast<ElfW(Shdr) *>(tmp_buf); - const int buf_entries = tmp_buf_size / sizeof(buf[0]); - const int buf_bytes = buf_entries * sizeof(buf[0]); + const size_t buf_entries = tmp_buf_size / sizeof(buf[0]); + const size_t buf_bytes = buf_entries * sizeof(buf[0]); - for (int i = 0; i < sh_num;) { - const ssize_t num_bytes_left = (sh_num - i) * sizeof(buf[0]); - const ssize_t num_bytes_to_read = + for (size_t i = 0; static_cast<int>(i) < sh_num;) { + const size_t num_bytes_left = + (static_cast<size_t>(sh_num) - i) * sizeof(buf[0]); + const size_t num_bytes_to_read = (buf_bytes > num_bytes_left) ? num_bytes_left : buf_bytes; - const off_t offset = sh_offset + i * sizeof(buf[0]); + const off_t offset = sh_offset + static_cast<off_t>(i * sizeof(buf[0])); const ssize_t len = ReadFromOffset(fd, buf, num_bytes_to_read, offset); - if (len % sizeof(buf[0]) != 0) { + if (len < 0) { + ABSL_RAW_LOG( + WARNING, + "Reading %zu bytes from offset %ju returned %zd which is negative.", + num_bytes_to_read, static_cast<intmax_t>(offset), len); + return false; + } + if (static_cast<size_t>(len) % sizeof(buf[0]) != 0) { ABSL_RAW_LOG( WARNING, - "Reading %zd bytes from offset %ju returned %zd which is not a " + "Reading %zu bytes from offset %jd returned %zd which is not a " "multiple of %zu.", - num_bytes_to_read, static_cast<uintmax_t>(offset), len, + num_bytes_to_read, static_cast<intmax_t>(offset), len, sizeof(buf[0])); return false; } - const ssize_t num_headers_in_buf = len / sizeof(buf[0]); + const size_t num_headers_in_buf = static_cast<size_t>(len) / sizeof(buf[0]); SAFE_ASSERT(num_headers_in_buf <= buf_entries); - for (int j = 0; j < num_headers_in_buf; ++j) { + for (size_t j = 0; j < num_headers_in_buf; ++j) { if (buf[j].sh_type == type) { *out = buf[j]; return true; @@ -518,9 +532,14 @@ bool ForEachSection(int fd, return false; } + // Technically it can be larger, but in practice this never happens. + if (elf_header.e_shentsize != sizeof(ElfW(Shdr))) { + return false; + } + ElfW(Shdr) shstrtab; - off_t shstrtab_offset = - (elf_header.e_shoff + elf_header.e_shentsize * elf_header.e_shstrndx); + off_t shstrtab_offset = static_cast<off_t>(elf_header.e_shoff) + + elf_header.e_shentsize * elf_header.e_shstrndx; if (!ReadFromOffsetExact(fd, &shstrtab, sizeof(shstrtab), shstrtab_offset)) { return false; } @@ -528,22 +547,23 @@ bool ForEachSection(int fd, for (int i = 0; i < elf_header.e_shnum; ++i) { ElfW(Shdr) out; off_t section_header_offset = - (elf_header.e_shoff + elf_header.e_shentsize * i); + static_cast<off_t>(elf_header.e_shoff) + elf_header.e_shentsize * i; if (!ReadFromOffsetExact(fd, &out, sizeof(out), section_header_offset)) { return false; } - off_t name_offset = shstrtab.sh_offset + out.sh_name; + off_t name_offset = static_cast<off_t>(shstrtab.sh_offset) + out.sh_name; char header_name[kMaxSectionNameLen]; ssize_t n_read = ReadFromOffset(fd, &header_name, kMaxSectionNameLen, name_offset); - if (n_read == -1) { + if (n_read < 0) { return false; } else if (n_read > kMaxSectionNameLen) { // Long read? return false; } - absl::string_view name(header_name, strnlen(header_name, n_read)); + absl::string_view name(header_name, + strnlen(header_name, static_cast<size_t>(n_read))); if (!callback(name, out)) { break; } @@ -569,20 +589,25 @@ bool GetSectionHeaderByName(int fd, const char *name, size_t name_len, return false; } + // Technically it can be larger, but in practice this never happens. + if (elf_header.e_shentsize != sizeof(ElfW(Shdr))) { + return false; + } + ElfW(Shdr) shstrtab; - off_t shstrtab_offset = - (elf_header.e_shoff + elf_header.e_shentsize * elf_header.e_shstrndx); + off_t shstrtab_offset = static_cast<off_t>(elf_header.e_shoff) + + elf_header.e_shentsize * elf_header.e_shstrndx; if (!ReadFromOffsetExact(fd, &shstrtab, sizeof(shstrtab), shstrtab_offset)) { return false; } for (int i = 0; i < elf_header.e_shnum; ++i) { off_t section_header_offset = - (elf_header.e_shoff + elf_header.e_shentsize * i); + static_cast<off_t>(elf_header.e_shoff) + elf_header.e_shentsize * i; if (!ReadFromOffsetExact(fd, out, sizeof(*out), section_header_offset)) { return false; } - off_t name_offset = shstrtab.sh_offset + out->sh_name; + off_t name_offset = static_cast<off_t>(shstrtab.sh_offset) + out->sh_name; ssize_t n_read = ReadFromOffset(fd, &header_name, name_len, name_offset); if (n_read < 0) { return false; @@ -633,17 +658,19 @@ static bool ShouldPickFirstSymbol(const ElfW(Sym) & symbol1, } // Return true if an address is inside a section. -static bool InSection(const void *address, const ElfW(Shdr) * section) { - const char *start = reinterpret_cast<const char *>(section->sh_addr); +static bool InSection(const void *address, ptrdiff_t relocation, + const ElfW(Shdr) * section) { + const char *start = reinterpret_cast<const char *>( + section->sh_addr + static_cast<ElfW(Addr)>(relocation)); size_t size = static_cast<size_t>(section->sh_size); return start <= address && address < (start + size); } static const char *ComputeOffset(const char *base, ptrdiff_t offset) { - // Note: cast to uintptr_t to avoid undefined behavior when base evaluates to + // Note: cast to intptr_t to avoid undefined behavior when base evaluates to // zero and offset is non-zero. - return reinterpret_cast<const char *>( - reinterpret_cast<uintptr_t>(base) + offset); + return reinterpret_cast<const char *>(reinterpret_cast<intptr_t>(base) + + offset); } // Read a symbol table and look for the symbol containing the @@ -656,42 +683,45 @@ static const char *ComputeOffset(const char *base, ptrdiff_t offset) { // To keep stack consumption low, we would like this function to not get // inlined. static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol( - const void *const pc, const int fd, char *out, int out_size, + const void *const pc, const int fd, char *out, size_t out_size, ptrdiff_t relocation, const ElfW(Shdr) * strtab, const ElfW(Shdr) * symtab, - const ElfW(Shdr) * opd, char *tmp_buf, int tmp_buf_size) { + const ElfW(Shdr) * opd, char *tmp_buf, size_t tmp_buf_size) { if (symtab == nullptr) { return SYMBOL_NOT_FOUND; } // Read multiple symbols at once to save read() calls. ElfW(Sym) *buf = reinterpret_cast<ElfW(Sym) *>(tmp_buf); - const int buf_entries = tmp_buf_size / sizeof(buf[0]); + const size_t buf_entries = tmp_buf_size / sizeof(buf[0]); - const int num_symbols = symtab->sh_size / symtab->sh_entsize; + const size_t num_symbols = symtab->sh_size / symtab->sh_entsize; // On platforms using an .opd section (PowerPC & IA64), a function symbol // has the address of a function descriptor, which contains the real // starting address. However, we do not always want to use the real // starting address because we sometimes want to symbolize a function // pointer into the .opd section, e.g. FindSymbol(&foo,...). - const bool pc_in_opd = - kPlatformUsesOPDSections && opd != nullptr && InSection(pc, opd); + const bool pc_in_opd = kPlatformUsesOPDSections && opd != nullptr && + InSection(pc, relocation, opd); const bool deref_function_descriptor_pointer = kPlatformUsesOPDSections && opd != nullptr && !pc_in_opd; ElfW(Sym) best_match; SafeMemZero(&best_match, sizeof(best_match)); bool found_match = false; - for (int i = 0; i < num_symbols;) { - off_t offset = symtab->sh_offset + i * symtab->sh_entsize; - const int num_remaining_symbols = num_symbols - i; - const int entries_in_chunk = std::min(num_remaining_symbols, buf_entries); - const int bytes_in_chunk = entries_in_chunk * sizeof(buf[0]); + for (size_t i = 0; i < num_symbols;) { + off_t offset = + static_cast<off_t>(symtab->sh_offset + i * symtab->sh_entsize); + const size_t num_remaining_symbols = num_symbols - i; + const size_t entries_in_chunk = + std::min(num_remaining_symbols, buf_entries); + const size_t bytes_in_chunk = entries_in_chunk * sizeof(buf[0]); const ssize_t len = ReadFromOffset(fd, buf, bytes_in_chunk, offset); - SAFE_ASSERT(len % sizeof(buf[0]) == 0); - const ssize_t num_symbols_in_buf = len / sizeof(buf[0]); + SAFE_ASSERT(len >= 0); + SAFE_ASSERT(static_cast<size_t>(len) % sizeof(buf[0]) == 0); + const size_t num_symbols_in_buf = static_cast<size_t>(len) / sizeof(buf[0]); SAFE_ASSERT(num_symbols_in_buf <= entries_in_chunk); - for (int j = 0; j < num_symbols_in_buf; ++j) { + for (size_t j = 0; j < num_symbols_in_buf; ++j) { const ElfW(Sym) &symbol = buf[j]; // For a DSO, a symbol address is relocated by the loading address. @@ -701,8 +731,18 @@ static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol( const char *start_address = ComputeOffset(original_start_address, relocation); +#ifdef __arm__ + // ARM functions are always aligned to multiples of two bytes; the + // lowest-order bit in start_address is ignored by the CPU and indicates + // whether the function contains ARM (0) or Thumb (1) code. We don't care + // about what encoding is being used; we just want the real start address + // of the function. + start_address = reinterpret_cast<const char *>( + reinterpret_cast<uintptr_t>(start_address) & ~1u); +#endif + if (deref_function_descriptor_pointer && - InSection(original_start_address, opd)) { + InSection(original_start_address, /*relocation=*/0, opd)) { // The opd section is mapped into memory. Just dereference // start_address to get the first double word, which points to the // function entry. @@ -711,7 +751,8 @@ static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol( // If pc is inside the .opd section, it points to a function descriptor. const size_t size = pc_in_opd ? kFunctionDescriptorSize : symbol.st_size; - const void *const end_address = ComputeOffset(start_address, size); + const void *const end_address = + ComputeOffset(start_address, static_cast<ptrdiff_t>(size)); if (symbol.st_value != 0 && // Skip null value symbols. symbol.st_shndx != 0 && // Skip undefined symbols. #ifdef STT_TLS @@ -729,16 +770,18 @@ static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol( } if (found_match) { - const size_t off = strtab->sh_offset + best_match.st_name; + const off_t off = + static_cast<off_t>(strtab->sh_offset) + best_match.st_name; const ssize_t n_read = ReadFromOffset(fd, out, out_size, off); if (n_read <= 0) { // This should never happen. ABSL_RAW_LOG(WARNING, - "Unable to read from fd %d at offset %zu: n_read = %zd", fd, - off, n_read); + "Unable to read from fd %d at offset %lld: n_read = %zd", fd, + static_cast<long long>(off), n_read); return SYMBOL_NOT_FOUND; } - ABSL_RAW_CHECK(n_read <= out_size, "ReadFromOffset read too much data."); + ABSL_RAW_CHECK(static_cast<size_t>(n_read) <= out_size, + "ReadFromOffset read too much data."); // strtab->sh_offset points into .strtab-like section that contains // NUL-terminated strings: '\0foo\0barbaz\0...". @@ -746,7 +789,7 @@ static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol( // sh_offset+st_name points to the start of symbol name, but we don't know // how long the symbol is, so we try to read as much as we have space for, // and usually over-read (i.e. there is a NUL somewhere before n_read). - if (memchr(out, '\0', n_read) == nullptr) { + if (memchr(out, '\0', static_cast<size_t>(n_read)) == nullptr) { // Either out_size was too small (n_read == out_size and no NUL), or // we tried to read past the EOF (n_read < out_size) and .strtab is // corrupt (missing terminating NUL; should never happen for valid ELF). @@ -764,7 +807,7 @@ static ABSL_ATTRIBUTE_NOINLINE FindSymbolResult FindSymbol( // See FindSymbol() comment for description of return value. FindSymbolResult Symbolizer::GetSymbolFromObjectFile( const ObjFile &obj, const void *const pc, const ptrdiff_t relocation, - char *out, int out_size, char *tmp_buf, int tmp_buf_size) { + char *out, size_t out_size, char *tmp_buf, size_t tmp_buf_size) { ElfW(Shdr) symtab; ElfW(Shdr) strtab; ElfW(Shdr) opd; @@ -787,13 +830,15 @@ FindSymbolResult Symbolizer::GetSymbolFromObjectFile( // Consult a regular symbol table, then fall back to the dynamic symbol table. for (const auto symbol_table_type : {SHT_SYMTAB, SHT_DYNSYM}) { if (!GetSectionHeaderByType(obj.fd, obj.elf_header.e_shnum, - obj.elf_header.e_shoff, symbol_table_type, + static_cast<off_t>(obj.elf_header.e_shoff), + static_cast<ElfW(Word)>(symbol_table_type), &symtab, tmp_buf, tmp_buf_size)) { continue; } if (!ReadFromOffsetExact( obj.fd, &strtab, sizeof(strtab), - obj.elf_header.e_shoff + symtab.sh_link * sizeof(symtab))) { + static_cast<off_t>(obj.elf_header.e_shoff + + symtab.sh_link * sizeof(symtab)))) { continue; } const FindSymbolResult rc = @@ -818,7 +863,7 @@ class FileDescriptor { ~FileDescriptor() { if (fd_ >= 0) { - NO_INTR(close(fd_)); + close(fd_); } } @@ -835,7 +880,7 @@ class FileDescriptor { // and snprintf(). class LineReader { public: - explicit LineReader(int fd, char *buf, int buf_len) + explicit LineReader(int fd, char *buf, size_t buf_len) : fd_(fd), buf_len_(buf_len), buf_(buf), @@ -863,12 +908,12 @@ class LineReader { bol_ = eol_ + 1; // Advance to the next line in the buffer. SAFE_ASSERT(bol_ <= eod_); // "bol_" can point to "eod_". if (!HasCompleteLine()) { - const int incomplete_line_length = eod_ - bol_; + const auto incomplete_line_length = static_cast<size_t>(eod_ - bol_); // Move the trailing incomplete line to the beginning. memmove(buf_, bol_, incomplete_line_length); // Read text from file and append it. char *const append_pos = buf_ + incomplete_line_length; - const int capacity_left = buf_len_ - incomplete_line_length; + const size_t capacity_left = buf_len_ - incomplete_line_length; const ssize_t num_bytes = ReadPersistent(fd_, append_pos, capacity_left); if (num_bytes <= 0) { // EOF or error. @@ -891,7 +936,8 @@ class LineReader { private: char *FindLineFeed() const { - return reinterpret_cast<char *>(memchr(bol_, '\n', eod_ - bol_)); + return reinterpret_cast<char *>( + memchr(bol_, '\n', static_cast<size_t>(eod_ - bol_))); } bool BufferIsEmpty() const { return buf_ == eod_; } @@ -901,7 +947,7 @@ class LineReader { } const int fd_; - const int buf_len_; + const size_t buf_len_; char *const buf_; char *bol_; char *eol_; @@ -919,7 +965,8 @@ static const char *GetHex(const char *start, const char *end, int ch = *p; if ((ch >= '0' && ch <= '9') || (ch >= 'A' && ch <= 'F') || (ch >= 'a' && ch <= 'f')) { - hex = (hex << 4) | (ch < 'A' ? ch - '0' : (ch & 0xF) + 9); + hex = (hex << 4) | + static_cast<uint64_t>(ch < 'A' ? ch - '0' : (ch & 0xF) + 9); } else { // Encountered the first non-hex character. break; } @@ -951,7 +998,7 @@ static bool ShouldUseMapping(const char *const flags) { static ABSL_ATTRIBUTE_NOINLINE bool ReadAddrMap( bool (*callback)(const char *filename, const void *const start_addr, const void *const end_addr, uint64_t offset, void *arg), - void *arg, void *tmp_buf, int tmp_buf_size) { + void *arg, void *tmp_buf, size_t tmp_buf_size) { // Use /proc/self/task/<pid>/maps instead of /proc/self/maps. The latter // requires kernel to stop all threads, and is significantly slower when there // are 1000s of threads. @@ -1066,10 +1113,10 @@ ObjFile *Symbolizer::FindObjFile(const void *const addr, size_t len) { } } - int lo = 0; - int hi = addr_map_.Size(); + size_t lo = 0; + size_t hi = addr_map_.Size(); while (lo < hi) { - int mid = (lo + hi) / 2; + size_t mid = (lo + hi) / 2; if (addr < addr_map_.At(mid)->end_addr) { hi = mid; } else { @@ -1091,11 +1138,11 @@ ObjFile *Symbolizer::FindObjFile(const void *const addr, size_t len) { } void Symbolizer::ClearAddrMap() { - for (int i = 0; i != addr_map_.Size(); i++) { + for (size_t i = 0; i != addr_map_.Size(); i++) { ObjFile *o = addr_map_.At(i); base_internal::LowLevelAlloc::Free(o->filename); if (o->fd >= 0) { - NO_INTR(close(o->fd)); + close(o->fd); } } addr_map_.Clear(); @@ -1111,7 +1158,7 @@ bool Symbolizer::RegisterObjFile(const char *filename, // Files are supposed to be added in the increasing address order. Make // sure that's the case. - int addr_map_size = impl->addr_map_.Size(); + size_t addr_map_size = impl->addr_map_.Size(); if (addr_map_size != 0) { ObjFile *old = impl->addr_map_.At(addr_map_size - 1); if (old->end_addr > end_addr) { @@ -1131,6 +1178,14 @@ bool Symbolizer::RegisterObjFile(const char *filename, reinterpret_cast<uintptr_t>(old->end_addr), old->filename); } return true; + } else if (old->end_addr == start_addr && + reinterpret_cast<uintptr_t>(old->start_addr) - old->offset == + reinterpret_cast<uintptr_t>(start_addr) - offset && + strcmp(old->filename, filename) == 0) { + // Two contiguous map entries that span a contiguous region of the file, + // perhaps because some part of the file was mlock()ed. Combine them. + old->end_addr = end_addr; + return true; } } ObjFile *obj = impl->addr_map_.Add(); @@ -1147,12 +1202,12 @@ bool Symbolizer::RegisterObjFile(const char *filename, // where the input symbol is demangled in-place. // To keep stack consumption low, we would like this function to not // get inlined. -static ABSL_ATTRIBUTE_NOINLINE void DemangleInplace(char *out, int out_size, +static ABSL_ATTRIBUTE_NOINLINE void DemangleInplace(char *out, size_t out_size, char *tmp_buf, - int tmp_buf_size) { + size_t tmp_buf_size) { if (Demangle(out, tmp_buf, tmp_buf_size)) { // Demangling succeeded. Copy to out if the space allows. - int len = strlen(tmp_buf); + size_t len = strlen(tmp_buf); if (len + 1 <= out_size) { // +1 for '\0'. SAFE_ASSERT(len < tmp_buf_size); memmove(out, tmp_buf, len + 1); @@ -1195,7 +1250,8 @@ const char *Symbolizer::InsertSymbolInCache(const void *const pc, SymbolCacheLine *line = GetCacheLine(pc); uint32_t max_age = 0; - int oldest_index = -1; + size_t oldest_index = 0; + bool found_oldest_index = false; for (size_t i = 0; i < ABSL_ARRAYSIZE(line->pc); ++i) { if (line->pc[i] == nullptr) { AgeSymbols(line); @@ -1207,11 +1263,12 @@ const char *Symbolizer::InsertSymbolInCache(const void *const pc, if (line->age[i] >= max_age) { max_age = line->age[i]; oldest_index = i; + found_oldest_index = true; } } AgeSymbols(line); - ABSL_RAW_CHECK(oldest_index >= 0, "Corrupt cache"); + ABSL_RAW_CHECK(found_oldest_index, "Corrupt cache"); base_internal::LowLevelAlloc::Free(line->name[oldest_index]); line->pc[oldest_index] = pc; line->name[oldest_index] = CopyString(name); @@ -1280,8 +1337,8 @@ static bool MaybeInitializeObjFile(ObjFile *obj) { } const int phnum = obj->elf_header.e_phnum; const int phentsize = obj->elf_header.e_phentsize; - size_t phoff = obj->elf_header.e_phoff; - int num_executable_load_segments = 0; + auto phoff = static_cast<off_t>(obj->elf_header.e_phoff); + size_t num_interesting_load_segments = 0; for (int j = 0; j < phnum; j++) { ElfW(Phdr) phdr; if (!ReadFromOffsetExact(obj->fd, &phdr, sizeof(phdr), phoff)) { @@ -1290,22 +1347,35 @@ static bool MaybeInitializeObjFile(ObjFile *obj) { return false; } phoff += phentsize; - constexpr int rx = PF_X | PF_R; - if (phdr.p_type != PT_LOAD || (phdr.p_flags & rx) != rx) { - // Not a LOAD segment, or not executable code. + +#if defined(__powerpc__) && !(_CALL_ELF > 1) + // On the PowerPC ELF v1 ABI, function pointers actually point to function + // descriptors. These descriptors are stored in an .opd section, which is + // mapped read-only. We thus need to look at all readable segments, not + // just the executable ones. + constexpr int interesting = PF_R; +#else + constexpr int interesting = PF_X | PF_R; +#endif + + if (phdr.p_type != PT_LOAD + || (phdr.p_flags & interesting) != interesting) { + // Not a LOAD segment, not executable code, and not a function + // descriptor. continue; } - if (num_executable_load_segments < obj->phdr.size()) { - memcpy(&obj->phdr[num_executable_load_segments++], &phdr, sizeof(phdr)); + if (num_interesting_load_segments < obj->phdr.size()) { + memcpy(&obj->phdr[num_interesting_load_segments++], &phdr, sizeof(phdr)); } else { - ABSL_RAW_LOG(WARNING, "%s: too many executable LOAD segments", - obj->filename); + ABSL_RAW_LOG( + WARNING, "%s: too many interesting LOAD segments: %zu >= %zu", + obj->filename, num_interesting_load_segments, obj->phdr.size()); break; } } - if (num_executable_load_segments == 0) { - // This object has no "r-x" LOAD segments. That's unexpected. - ABSL_RAW_LOG(WARNING, "%s: no executable LOAD segments", obj->filename); + if (num_interesting_load_segments == 0) { + // This object has no interesting LOAD segments. That's unexpected. + ABSL_RAW_LOG(WARNING, "%s: no interesting LOAD segments", obj->filename); return false; } } @@ -1319,13 +1389,7 @@ static bool MaybeInitializeObjFile(ObjFile *obj) { // they are called here as well. // To keep stack consumption low, we would like this function to not // get inlined. -const char *Symbolizer::GetSymbol(const void *const pc) { - const char *entry = FindSymbolInCache(pc); - if (entry != nullptr) { - return entry; - } - symbol_buf_[0] = '\0'; - +const char *Symbolizer::GetUncachedSymbol(const void *pc) { ObjFile *const obj = FindObjFile(pc, 1); ptrdiff_t relocation = 0; int fd = -1; @@ -1337,12 +1401,12 @@ const char *Symbolizer::GetSymbol(const void *const pc) { // // For obj->offset > 0, adjust the relocation since a mapping at offset // X in the file will have a start address of [true relocation]+X. - relocation = start_addr - obj->offset; + relocation = static_cast<ptrdiff_t>(start_addr - obj->offset); - // Note: some binaries have multiple "rx" LOAD segments. We must - // find the right one. + // Note: some binaries have multiple LOAD segments that can contain + // function pointers. We must find the right one. ElfW(Phdr) *phdr = nullptr; - for (int j = 0; j < obj->phdr.size(); j++) { + for (size_t j = 0; j < obj->phdr.size(); j++) { ElfW(Phdr) &p = obj->phdr[j]; if (p.p_type != PT_LOAD) { // We only expect PT_LOADs. This must be PT_NULL that we didn't @@ -1350,7 +1414,7 @@ const char *Symbolizer::GetSymbol(const void *const pc) { ABSL_RAW_CHECK(p.p_type == PT_NULL, "unexpected p_type"); break; } - if (pc < reinterpret_cast<void *>(start_addr + p.p_memsz)) { + if (pc < reinterpret_cast<void *>(start_addr + p.p_vaddr + p.p_memsz)) { phdr = &p; break; } @@ -1413,6 +1477,42 @@ const char *Symbolizer::GetSymbol(const void *const pc) { return InsertSymbolInCache(pc, symbol_buf_); } +const char *Symbolizer::GetSymbol(const void *pc) { + const char *entry = FindSymbolInCache(pc); + if (entry != nullptr) { + return entry; + } + symbol_buf_[0] = '\0'; + +#ifdef __hppa__ + { + // In some contexts (e.g., return addresses), PA-RISC uses the lowest two + // bits of the address to indicate the privilege level. Clear those bits + // before trying to symbolize. + const auto pc_bits = reinterpret_cast<uintptr_t>(pc); + const auto address = pc_bits & ~0x3; + entry = GetUncachedSymbol(reinterpret_cast<const void *>(address)); + if (entry != nullptr) { + return entry; + } + + // In some contexts, PA-RISC also uses bit 1 of the address to indicate that + // this is a cross-DSO function pointer. Such function pointers actually + // point to a procedure label, a struct whose first 32-bit (pointer) element + // actually points to the function text. With no symbol found for this + // address so far, try interpreting it as a cross-DSO function pointer and + // see how that goes. + if (pc_bits & 0x2) { + return GetUncachedSymbol(*reinterpret_cast<const void *const *>(address)); + } + + return nullptr; + } +#else + return GetUncachedSymbol(pc); +#endif +} + bool RemoveAllSymbolDecorators(void) { if (!g_decorators_mu.TryLock()) { // Someone else is using decorators. Get out. @@ -1476,7 +1576,7 @@ bool RegisterFileMappingHint(const void *start, const void *end, uint64_t offset ret = false; } else { // TODO(ckennelly): Move this into a string copy routine. - int len = strlen(filename); + size_t len = strlen(filename); char *dst = static_cast<char *>( base_internal::LowLevelAlloc::AllocWithArena(len + 1, SigSafeArena())); ABSL_RAW_CHECK(dst != nullptr, "out of memory"); @@ -1532,16 +1632,17 @@ bool Symbolize(const void *pc, char *out, int out_size) { const char *name = s->GetSymbol(pc); bool ok = false; if (name != nullptr && out_size > 0) { - strncpy(out, name, out_size); + strncpy(out, name, static_cast<size_t>(out_size)); ok = true; - if (out[out_size - 1] != '\0') { + if (out[static_cast<size_t>(out_size) - 1] != '\0') { // strncpy() does not '\0' terminate when it truncates. Do so, with // trailing ellipsis. static constexpr char kEllipsis[] = "..."; - int ellipsis_size = - std::min(implicit_cast<int>(strlen(kEllipsis)), out_size - 1); - memcpy(out + out_size - ellipsis_size - 1, kEllipsis, ellipsis_size); - out[out_size - 1] = '\0'; + size_t ellipsis_size = + std::min(strlen(kEllipsis), static_cast<size_t>(out_size) - 1); + memcpy(out + static_cast<size_t>(out_size) - ellipsis_size - 1, kEllipsis, + ellipsis_size); + out[static_cast<size_t>(out_size) - 1] = '\0'; } } debugging_internal::FreeSymbolizer(s); |