1// Copyright 2018 The Abseil Authors. 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// https://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15// See "Retrieving Symbol Information by Address": 16// https://msdn.microsoft.com/en-us/library/windows/desktop/ms680578(v=vs.85).aspx 17 18#include <windows.h> 19 20// MSVC header dbghelp.h has a warning for an ignored typedef. 21#pragma warning(push) 22#pragma warning(disable:4091) 23#include <dbghelp.h> 24#pragma warning(pop) 25 26#pragma comment(lib, "dbghelp.lib") 27 28#include <algorithm> 29#include <cstring> 30 31#include "absl/base/internal/raw_logging.h" 32 33namespace absl { 34ABSL_NAMESPACE_BEGIN 35 36static HANDLE process = NULL; 37 38void InitializeSymbolizer(const char*) { 39 if (process != nullptr) { 40 return; 41 } 42 process = GetCurrentProcess(); 43 44 // Symbols are not loaded until a reference is made requiring the 45 // symbols be loaded. This is the fastest, most efficient way to use 46 // the symbol handler. 47 SymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_UNDNAME); 48 if (!SymInitialize(process, nullptr, true)) { 49 // GetLastError() returns a Win32 DWORD, but we assign to 50 // unsigned long long to simplify the ABSL_RAW_LOG case below. The uniform 51 // initialization guarantees this is not a narrowing conversion. 52 const unsigned long long error{GetLastError()}; // NOLINT(runtime/int) 53 ABSL_RAW_LOG(FATAL, "SymInitialize() failed: %llu", error); 54 } 55} 56 57bool Symbolize(const void* pc, char* out, int out_size) { 58 if (out_size <= 0) { 59 return false; 60 } 61 alignas(SYMBOL_INFO) char buf[sizeof(SYMBOL_INFO) + MAX_SYM_NAME]; 62 SYMBOL_INFO* symbol = reinterpret_cast<SYMBOL_INFO*>(buf); 63 symbol->SizeOfStruct = sizeof(SYMBOL_INFO); 64 symbol->MaxNameLen = MAX_SYM_NAME; 65 if (!SymFromAddr(process, reinterpret_cast<DWORD64>(pc), nullptr, symbol)) { 66 return false; 67 } 68 strncpy(out, symbol->Name, out_size); 69 if (out[out_size - 1] != '\0') { 70 // strncpy() does not '\0' terminate when it truncates. 71 static constexpr char kEllipsis[] = "..."; 72 int ellipsis_size = 73 std::min<int>(sizeof(kEllipsis) - 1, out_size - 1); 74 memcpy(out + out_size - ellipsis_size - 1, kEllipsis, ellipsis_size); 75 out[out_size - 1] = '\0'; 76 } 77 return true; 78} 79 80ABSL_NAMESPACE_END 81} // namespace absl 82