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Unified Diff: base/third_party/symbolize/symbolize.cc

Issue 545148: Import google-glog's Symbolize() and use it in debug_util_posix.cc. (Closed)
Patch Set: Fix checkdeps.py error Created 10 years, 11 months ago
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Index: base/third_party/symbolize/symbolize.cc
diff --git a/base/third_party/symbolize/symbolize.cc b/base/third_party/symbolize/symbolize.cc
new file mode 100644
index 0000000000000000000000000000000000000000..3465de6c6feb2a3eab1cff862196e10e999d42b2
--- /dev/null
+++ b/base/third_party/symbolize/symbolize.cc
@@ -0,0 +1,681 @@
+// Copyright (c) 2006, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: Satoru Takabayashi
+// Stack-footprint reduction work done by Raksit Ashok
+//
+// Implementation note:
+//
+// We don't use heaps but only use stacks. We want to reduce the
+// stack consumption so that the symbolizer can run on small stacks.
+//
+// Here are some numbers collected with GCC 4.1.0 on x86:
+// - sizeof(Elf32_Sym) = 16
+// - sizeof(Elf32_Shdr) = 40
+// - sizeof(Elf64_Sym) = 24
+// - sizeof(Elf64_Shdr) = 64
+//
+// This implementation is intended to be async-signal-safe but uses
+// some functions which are not guaranteed to be so, such as memchr()
+// and memmove(). We assume they are async-signal-safe.
+//
+
+#include "utilities.h"
+
+#if defined(HAVE_SYMBOLIZE)
+
+#include <limits>
+
+#include "symbolize.h"
+#include "demangle.h"
+
+_START_GOOGLE_NAMESPACE_
+
+// We don't use assert() since it's not guaranteed to be
+// async-signal-safe. Instead we define a minimal assertion
+// macro. So far, we don't need pretty printing for __FILE__, etc.
+
+// A wrapper for abort() to make it callable in ? :.
+static int AssertFail() {
+ abort();
+ return 0; // Should not reach.
+}
+
+#define SAFE_ASSERT(expr) ((expr) ? 0 : AssertFail())
+
+static SymbolizeCallback g_symbolize_callback = NULL;
+void InstallSymbolizeCallback(SymbolizeCallback callback) {
+ g_symbolize_callback = callback;
+}
+
+// This function wraps the Demangle function to provide an interface
+// where the input symbol is demangled in-place.
+// To keep stack consumption low, we would like this function to not
+// get inlined.
+static ATTRIBUTE_NOINLINE void DemangleInplace(char *out, int out_size) {
+ char demangled[256]; // Big enough for sane demangled symbols.
+ if (Demangle(out, demangled, sizeof(demangled))) {
+ // Demangling succeeded. Copy to out if the space allows.
+ int len = strlen(demangled);
+ if (len + 1 <= out_size) { // +1 for '\0'.
+ SAFE_ASSERT(len < sizeof(demangled));
+ memmove(out, demangled, len + 1);
+ }
+ }
+}
+
+_END_GOOGLE_NAMESPACE_
+
+#if defined(__ELF__)
+
+#include <dlfcn.h>
+#include <elf.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <link.h> // For ElfW() macro.
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "symbolize.h"
+#include "config.h"
+#include "glog/raw_logging.h"
+
+// Re-runs fn until it doesn't cause EINTR.
+#define NO_INTR(fn) do {} while ((fn) < 0 && errno == EINTR)
+
+_START_GOOGLE_NAMESPACE_
+
+// Read up to "count" bytes from file descriptor "fd" into the buffer
+// starting at "buf" while handling short reads and EINTR. On
+// success, return the number of bytes read. Otherwise, return -1.
+static ssize_t ReadPersistent(const int fd, void *buf, const size_t count) {
+ SAFE_ASSERT(fd >= 0);
+ SAFE_ASSERT(count >= 0 && count <= std::numeric_limits<ssize_t>::max());
+ char *buf0 = reinterpret_cast<char *>(buf);
+ ssize_t num_bytes = 0;
+ while (num_bytes < count) {
+ ssize_t len;
+ NO_INTR(len = read(fd, buf0 + num_bytes, count - num_bytes));
+ if (len < 0) { // There was an error other than EINTR.
+ return -1;
+ }
+ if (len == 0) { // Reached EOF.
+ break;
+ }
+ num_bytes += len;
+ }
+ SAFE_ASSERT(num_bytes <= count);
+ return num_bytes;
+}
+
+// Read up to "count" bytes from "offset" in the file pointed by file
+// descriptor "fd" into the buffer starting at "buf". On success,
+// return the number of bytes read. Otherwise, return -1.
+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) {
+ return -1;
+ }
+ return ReadPersistent(fd, buf, count);
+}
+
+// Try reading exactly "count" bytes from "offset" bytes in a file
+// pointed by "fd" into the buffer starting at "buf" while handling
+// short reads and EINTR. On success, return true. Otherwise, return
+// false.
+static bool ReadFromOffsetExact(const int fd, void *buf,
+ const size_t count, const off_t offset) {
+ ssize_t len = ReadFromOffset(fd, buf, count, offset);
+ return len == count;
+}
+
+// Returns elf_header.e_type if the file pointed by fd is an ELF binary.
+static int FileGetElfType(const int fd) {
+ ElfW(Ehdr) elf_header;
+ if (!ReadFromOffsetExact(fd, &elf_header, sizeof(elf_header), 0)) {
+ return -1;
+ }
+ if (memcmp(elf_header.e_ident, ELFMAG, SELFMAG) != 0) {
+ return -1;
+ }
+ return elf_header.e_type;
+}
+
+// Read the section headers in the given ELF binary, and if a section
+// of the specified type is found, set the output to this section header
+// and return true. Otherwise, return false.
+// To keep stack consumption low, we would like this function to not get
+// inlined.
+static ATTRIBUTE_NOINLINE bool
+GetSectionHeaderByType(const int fd, ElfW(Half) sh_num, const off_t sh_offset,
+ ElfW(Word) type, ElfW(Shdr) *out) {
+ // Read at most 16 section headers at a time to save read calls.
+ ElfW(Shdr) buf[16];
+ 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 =
+ (sizeof(buf) > num_bytes_left) ? num_bytes_left : sizeof(buf);
+ const ssize_t len = ReadFromOffset(fd, buf, num_bytes_to_read,
+ sh_offset + i * sizeof(buf[0]));
+ SAFE_ASSERT(len % sizeof(buf[0]) == 0);
+ const ssize_t num_headers_in_buf = len / sizeof(buf[0]);
+ SAFE_ASSERT(num_headers_in_buf <= sizeof(buf) / sizeof(buf[0]));
+ for (int j = 0; j < num_headers_in_buf; ++j) {
+ if (buf[j].sh_type == type) {
+ *out = buf[j];
+ return true;
+ }
+ }
+ i += num_headers_in_buf;
+ }
+ return false;
+}
+
+// There is no particular reason to limit section name to 63 characters,
+// but there has (as yet) been no need for anything longer either.
+const int kMaxSectionNameLen = 64;
+
+// name_len should include terminating '\0'.
+bool GetSectionHeaderByName(int fd, const char *name, size_t name_len,
+ ElfW(Shdr) *out) {
+ ElfW(Ehdr) elf_header;
+ if (!ReadFromOffsetExact(fd, &elf_header, sizeof(elf_header), 0)) {
+ return false;
+ }
+
+ ElfW(Shdr) shstrtab;
+ off_t shstrtab_offset = (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);
+ if (!ReadFromOffsetExact(fd, out, sizeof(*out), section_header_offset)) {
+ return false;
+ }
+ char header_name[kMaxSectionNameLen];
+ if (sizeof(header_name) < name_len) {
+ RAW_LOG(WARNING, "Section name '%s' is too long (%"PRIuS"); "
+ "section will not be found (even if present).", name, name_len);
+ // No point in even trying.
+ return false;
+ }
+ off_t name_offset = shstrtab.sh_offset + out->sh_name;
+ ssize_t n_read = ReadFromOffset(fd, &header_name, name_len, name_offset);
+ if (n_read == -1) {
+ return false;
+ } else if (n_read != name_len) {
+ // Short read -- name could be at end of file.
+ continue;
+ }
+ if (memcmp(header_name, name, name_len) == 0) {
+ return true;
+ }
+ }
+ return false;
+}
+
+// Read a symbol table and look for the symbol containing the
+// pc. Iterate over symbols in a symbol table and look for the symbol
+// containing "pc". On success, return true and write the symbol name
+// to out. Otherwise, return false.
+// To keep stack consumption low, we would like this function to not get
+// inlined.
+static ATTRIBUTE_NOINLINE bool
+FindSymbol(uint64_t pc, const int fd, char *out, int out_size,
+ uint64_t symbol_offset, const ElfW(Shdr) *strtab,
+ const ElfW(Shdr) *symtab) {
+ if (symtab == NULL) {
+ return false;
+ }
+ const int num_symbols = symtab->sh_size / symtab->sh_entsize;
+ for (int i = 0; i < num_symbols;) {
+ off_t offset = symtab->sh_offset + i * symtab->sh_entsize;
+
+ // If we are reading Elf64_Sym's, we want to limit this array to
+ // 32 elements (to keep stack consumption low), otherwise we can
+ // have a 64 element Elf32_Sym array.
+#if __WORDSIZE == 64
+#define NUM_SYMBOLS 32
+#else
+#define NUM_SYMBOLS 64
+#endif
+
+ // Read at most NUM_SYMBOLS symbols at once to save read() calls.
+ ElfW(Sym) buf[NUM_SYMBOLS];
+ const ssize_t len = ReadFromOffset(fd, &buf, sizeof(buf), offset);
+ SAFE_ASSERT(len % sizeof(buf[0]) == 0);
+ const ssize_t num_symbols_in_buf = len / sizeof(buf[0]);
+ SAFE_ASSERT(num_symbols_in_buf <= sizeof(buf)/sizeof(buf[0]));
+ for (int j = 0; j < num_symbols_in_buf; ++j) {
+ const ElfW(Sym)& symbol = buf[j];
+ uint64_t start_address = symbol.st_value;
+ start_address += symbol_offset;
+ uint64_t end_address = start_address + symbol.st_size;
+ if (symbol.st_value != 0 && // Skip null value symbols.
+ symbol.st_shndx != 0 && // Skip undefined symbols.
+ start_address <= pc && pc < end_address) {
+ ssize_t len1 = ReadFromOffset(fd, out, out_size,
+ strtab->sh_offset + symbol.st_name);
+ if (len1 <= 0 || memchr(out, '\0', out_size) == NULL) {
+ return false;
+ }
+ return true; // Obtained the symbol name.
+ }
+ }
+ i += num_symbols_in_buf;
+ }
+ return false;
+}
+
+// Get the symbol name of "pc" from the file pointed by "fd". Process
+// both regular and dynamic symbol tables if necessary. On success,
+// write the symbol name to "out" and return true. Otherwise, return
+// false.
+static bool GetSymbolFromObjectFile(const int fd, uint64_t pc,
+ char *out, int out_size,
+ uint64_t map_start_address) {
+ // Read the ELF header.
+ ElfW(Ehdr) elf_header;
+ if (!ReadFromOffsetExact(fd, &elf_header, sizeof(elf_header), 0)) {
+ return false;
+ }
+
+ uint64_t symbol_offset = 0;
+ if (elf_header.e_type == ET_DYN) { // DSO needs offset adjustment.
+ symbol_offset = map_start_address;
+ }
+
+ ElfW(Shdr) symtab, strtab;
+
+ // Consult a regular symbol table first.
+ if (!GetSectionHeaderByType(fd, elf_header.e_shnum, elf_header.e_shoff,
+ SHT_SYMTAB, &symtab)) {
+ return false;
+ }
+ if (!ReadFromOffsetExact(fd, &strtab, sizeof(strtab), elf_header.e_shoff +
+ symtab.sh_link * sizeof(symtab))) {
+ return false;
+ }
+ if (FindSymbol(pc, fd, out, out_size, symbol_offset,
+ &strtab, &symtab)) {
+ return true; // Found the symbol in a regular symbol table.
+ }
+
+ // If the symbol is not found, then consult a dynamic symbol table.
+ if (!GetSectionHeaderByType(fd, elf_header.e_shnum, elf_header.e_shoff,
+ SHT_DYNSYM, &symtab)) {
+ return false;
+ }
+ if (!ReadFromOffsetExact(fd, &strtab, sizeof(strtab), elf_header.e_shoff +
+ symtab.sh_link * sizeof(symtab))) {
+ return false;
+ }
+ if (FindSymbol(pc, fd, out, out_size, symbol_offset,
+ &strtab, &symtab)) {
+ return true; // Found the symbol in a dynamic symbol table.
+ }
+
+ return false;
+}
+
+namespace {
+// Thin wrapper around a file descriptor so that the file descriptor
+// gets closed for sure.
+struct FileDescriptor {
+ const int fd_;
+ explicit FileDescriptor(int fd) : fd_(fd) {}
+ ~FileDescriptor() {
+ if (fd_ >= 0) {
+ NO_INTR(close(fd_));
+ }
+ }
+ int get() { return fd_; }
+
+ private:
+ explicit FileDescriptor(const FileDescriptor&);
+ void operator=(const FileDescriptor&);
+};
+
+// Helper class for reading lines from file.
+//
+// Note: we don't use ProcMapsIterator since the object is big (it has
+// a 5k array member) and uses async-unsafe functions such as sscanf()
+// and snprintf().
+class LineReader {
+ public:
+ explicit LineReader(int fd, char *buf, int buf_len) : fd_(fd),
+ buf_(buf), buf_len_(buf_len), bol_(buf), eol_(buf), eod_(buf) {
+ }
+
+ // Read '\n'-terminated line from file. On success, modify "bol"
+ // and "eol", then return true. Otherwise, return false.
+ //
+ // Note: if the last line doesn't end with '\n', the line will be
+ // dropped. It's an intentional behavior to make the code simple.
+ bool ReadLine(const char **bol, const char **eol) {
+ if (BufferIsEmpty()) { // First time.
+ const ssize_t num_bytes = ReadPersistent(fd_, buf_, buf_len_);
+ if (num_bytes <= 0) { // EOF or error.
+ return false;
+ }
+ eod_ = buf_ + num_bytes;
+ bol_ = buf_;
+ } else {
+ 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_;
+ // 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 ssize_t num_bytes = ReadPersistent(fd_, append_pos,
+ capacity_left);
+ if (num_bytes <= 0) { // EOF or error.
+ return false;
+ }
+ eod_ = append_pos + num_bytes;
+ bol_ = buf_;
+ }
+ }
+ eol_ = FindLineFeed();
+ if (eol_ == NULL) { // '\n' not found. Malformed line.
+ return false;
+ }
+ *eol_ = '\0'; // Replace '\n' with '\0'.
+
+ *bol = bol_;
+ *eol = eol_;
+ return true;
+ }
+
+ // Beginning of line.
+ const char *bol() {
+ return bol_;
+ }
+
+ // End of line.
+ const char *eol() {
+ return eol_;
+ }
+
+ private:
+ explicit LineReader(const LineReader&);
+ void operator=(const LineReader&);
+
+ char *FindLineFeed() {
+ return reinterpret_cast<char *>(memchr(bol_, '\n', eod_ - bol_));
+ }
+
+ bool BufferIsEmpty() {
+ return buf_ == eod_;
+ }
+
+ bool HasCompleteLine() {
+ return !BufferIsEmpty() && FindLineFeed() != NULL;
+ }
+
+ const int fd_;
+ char * const buf_;
+ const int buf_len_;
+ char *bol_;
+ char *eol_;
+ const char *eod_; // End of data in "buf_".
+};
+} // namespace
+
+// Place the hex number read from "start" into "*hex". The pointer to
+// the first non-hex character or "end" is returned.
+static char *GetHex(const char *start, const char *end, uint64_t *hex) {
+ *hex = 0;
+ const char *p;
+ for (p = start; p < end; ++p) {
+ 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);
+ } else { // Encountered the first non-hex character.
+ break;
+ }
+ }
+ SAFE_ASSERT(p <= end);
+ return const_cast<char *>(p);
+}
+
+// Search for the object file (from /proc/self/maps) that contains
+// the specified pc. If found, open this file and return the file handle,
+// and also set start_address to the start address of where this object
+// file is mapped to in memory. Otherwise, return -1.
+static ATTRIBUTE_NOINLINE int
+OpenObjectFileContainingPcAndGetStartAddress(uint64_t pc,
+ uint64_t &start_address) {
+ int object_fd;
+
+ // Open /proc/self/maps.
+ int maps_fd;
+ NO_INTR(maps_fd = open("/proc/self/maps", O_RDONLY));
+ FileDescriptor wrapped_maps_fd(maps_fd);
+ if (wrapped_maps_fd.get() < 0) {
+ return -1;
+ }
+
+ // Iterate over maps and look for the map containing the pc. Then
+ // look into the symbol tables inside.
+ char buf[1024]; // Big enough for line of sane /proc/self/maps
+ LineReader reader(wrapped_maps_fd.get(), buf, sizeof(buf));
+ while (true) {
+ const char *cursor;
+ const char *eol;
+ if (!reader.ReadLine(&cursor, &eol)) { // EOF or malformed line.
+ return -1;
+ }
+
+ // Start parsing line in /proc/self/maps. Here is an example:
+ //
+ // 08048000-0804c000 r-xp 00000000 08:01 2142121 /bin/cat
+ //
+ // We want start address (08048000), end address (0804c000), flags
+ // (r-xp) and file name (/bin/cat).
+
+ // Read start address.
+ cursor = GetHex(cursor, eol, &start_address);
+ if (cursor == eol || *cursor != '-') {
+ return -1; // Malformed line.
+ }
+ ++cursor; // Skip '-'.
+
+ // Read end address.
+ uint64_t end_address;
+ cursor = GetHex(cursor, eol, &end_address);
+ if (cursor == eol || *cursor != ' ') {
+ return -1; // Malformed line.
+ }
+ ++cursor; // Skip ' '.
+
+ // Check start and end addresses.
+ if (!(start_address <= pc && pc < end_address)) {
+ continue; // We skip this map. PC isn't in this map.
+ }
+
+ // Read flags. Skip flags until we encounter a space or eol.
+ const char * const flags_start = cursor;
+ while (cursor < eol && *cursor != ' ') {
+ ++cursor;
+ }
+ // We expect at least four letters for flags (ex. "r-xp").
+ if (cursor == eol || cursor < flags_start + 4) {
+ return -1; // Malformed line.
+ }
+
+ // Check flags. We are only interested in "r-x" maps.
+ if (memcmp(flags_start, "r-x", 3) != 0) { // Not a "r-x" map.
+ continue; // We skip this map.
+ }
+ ++cursor; // Skip ' '.
+
+ // Skip to file name. "cursor" now points to file offset. We need to
+ // skip at least three spaces for file offset, dev, and inode.
+ int num_spaces = 0;
+ while (cursor < eol) {
+ if (*cursor == ' ') {
+ ++num_spaces;
+ } else if (num_spaces >= 3) {
+ // The first non-space character after skipping three spaces
+ // is the beginning of the file name.
+ break;
+ }
+ ++cursor;
+ }
+ if (cursor == eol) {
+ return -1; // Malformed line.
+ }
+
+ // Finally, "cursor" now points to file name of our interest.
+ NO_INTR(object_fd = open(cursor, O_RDONLY));
+ if (object_fd < 0) {
+ return -1;
+ }
+ return object_fd;
+ }
+}
+
+// The implementation of our symbolization routine. If it
+// successfully finds the symbol containing "pc" and obtains the
+// symbol name, returns true and write the symbol name to "out".
+// Otherwise, returns false. If Callback function is installed via
+// InstallSymbolizeCallback(), the function is also called in this function,
+// and "out" is used as its output.
+// To keep stack consumption low, we would like this function to not
+// get inlined.
+static ATTRIBUTE_NOINLINE bool SymbolizeAndDemangle(void *pc, char *out,
+ int out_size) {
+ uint64_t pc0 = reinterpret_cast<uintptr_t>(pc);
+ uint64_t start_address = 0;
+
+ int object_fd = OpenObjectFileContainingPcAndGetStartAddress(pc0,
+ start_address);
+ if (object_fd == -1) {
+ return false;
+ }
+ FileDescriptor wrapped_object_fd(object_fd);
+ int elf_type = FileGetElfType(wrapped_object_fd.get());
+ if (elf_type == -1) {
+ return false;
+ }
+ if (g_symbolize_callback) {
+ // Run the call back if it's installed.
+ // Note: relocation (and much of the rest of this code) will be
+ // wrong for prelinked shared libraries and PIE executables.
+ uint64 relocation = (elf_type == ET_DYN) ? start_address : 0;
+ int num_bytes_written = g_symbolize_callback(wrapped_object_fd.get(),
+ pc, out, out_size,
+ relocation);
+ if (num_bytes_written > 0) {
+ out += num_bytes_written;
+ out_size -= num_bytes_written;
+ }
+ }
+ if (!GetSymbolFromObjectFile(wrapped_object_fd.get(), pc0,
+ out, out_size, start_address)) {
+ return false;
+ }
+
+ // Symbolization succeeded. Now we try to demangle the symbol.
+ DemangleInplace(out, out_size);
+ return true;
+}
+
+_END_GOOGLE_NAMESPACE_
+
+#elif defined(OS_MACOSX) && defined(HAVE_DLADDR)
+
+#include <dlfcn.h>
+#include <string.h>
+
+_START_GOOGLE_NAMESPACE_
+
+static ATTRIBUTE_NOINLINE bool SymbolizeAndDemangle(void *pc, char *out,
+ int out_size) {
+ Dl_info info;
+ if (dladdr(pc, &info)) {
+ if (strlen(info.dli_sname) < out_size) {
+ strcpy(out, info.dli_sname);
+ // Symbolization succeeded. Now we try to demangle the symbol.
+ DemangleInplace(out, out_size);
+ return true;
+ }
+ }
+ return false;
+}
+
+_END_GOOGLE_NAMESPACE_
+
+#else
+# error BUG: HAVE_SYMBOLIZE was wrongly set
+#endif
+
+_START_GOOGLE_NAMESPACE_
+
+bool Symbolize(void *pc, char *out, int out_size) {
+ SAFE_ASSERT(out_size >= 0);
+ return SymbolizeAndDemangle(pc, out, out_size);
+}
+
+_END_GOOGLE_NAMESPACE_
+
+#else /* HAVE_SYMBOLIZE */
+
+#include <assert.h>
+
+#include "config.h"
+
+_START_GOOGLE_NAMESPACE_
+
+// TODO: Support other environments.
+bool Symbolize(void *pc, char *out, int out_size) {
+ assert(0);
+ return false;
+}
+
+_END_GOOGLE_NAMESPACE_
+
+#endif

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