// Copyright 2018 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// See "Retrieving Symbol Information by Address":
// https://msdn.microsoft.com/en-us/library/windows/desktop/ms680578(v=vs.85).aspx
#include <windows.h>
// MSVC header dbghelp.h has a warning for an ignored typedef.
#pragma warning(push)
#pragma warning(disable:4091)
#include <dbghelp.h>
#pragma warning(pop)
#pragma comment(lib, "dbghelp.lib")
#include <algorithm>
#include <cstring>
#include "absl/base/internal/raw_logging.h"
namespace absl {
static HANDLE process = NULL;
void InitializeSymbolizer(const char*) {
if (process != nullptr) {
return;
}
process = GetCurrentProcess();
// Symbols are not loaded until a reference is made requiring the
// symbols be loaded. This is the fastest, most efficient way to use
// the symbol handler.
SymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_UNDNAME);
if (!SymInitialize(process, nullptr, true)) {
// GetLastError() returns a Win32 DWORD, but we assign to
// unsigned long long to simplify the ABSL_RAW_LOG case below. The uniform
// initialization guarantees this is not a narrowing conversion.
const unsigned long long error{GetLastError()}; // NOLINT(runtime/int)
ABSL_RAW_LOG(FATAL, "SymInitialize() failed: %llu", error);
}
}
bool Symbolize(const void* pc, char* out, int out_size) {
if (out_size <= 0) {
return false;
}
alignas(SYMBOL_INFO) char buf[sizeof(SYMBOL_INFO) + MAX_SYM_NAME];
SYMBOL_INFO* symbol = reinterpret_cast<SYMBOL_INFO*>(buf);
symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
symbol->MaxNameLen = MAX_SYM_NAME;
if (!SymFromAddr(process, reinterpret_cast<DWORD64>(pc), nullptr, symbol)) {
return false;
}
strncpy(out, symbol->Name, out_size);
if (out[out_size - 1] != '\0') {
// strncpy() does not '\0' terminate when it truncates.
static constexpr char kEllipsis[] = "...";
int ellipsis_size =
std::min<int>(sizeof(kEllipsis) - 1, out_size - 1);
memcpy(out + out_size - ellipsis_size - 1, kEllipsis, ellipsis_size);
out[out_size - 1] = '\0';
}
return true;
}
} // namespace absl
