blob: 87045a75fde98daac8cbacbeaddef695f388e62b [file] [log] [blame]
// Copyright (c) 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <stdio.h>
#include <atomic>
#include <string>
#include <unordered_set>
#include <windows.h> // Needs to be included before the others.
#include <dbghelp.h>
#include <process.h>
namespace {
// The main purpose of the order file is to optimize startup time,
// so capturing the first N function calls is enough.
static constexpr int kSamplesCapacity = 25 * 1024 * 1024;
void* samples[kSamplesCapacity];
std::atomic_int num_samples;
std::atomic_int done;
// Path to the dump file. %lu will be substituted by the process id.
static const char kDumpFile[] = "/src/tmp/cygprofile_%lu.txt";
// Symbolize the samples and write them to disk.
void dump(void*) {
HMODULE dbghelp = LoadLibraryA("dbghelp.dll");
auto sym_from_addr = reinterpret_cast<decltype(::SymFromAddr)*>(
::GetProcAddress(dbghelp, "SymFromAddr"));
auto sym_initialize = reinterpret_cast<decltype(::SymInitialize)*>(
::GetProcAddress(dbghelp, "SymInitialize"));
auto sym_set_options = reinterpret_cast<decltype(::SymSetOptions)*>(
::GetProcAddress(dbghelp, "SymSetOptions"));
char filename[MAX_PATH];
snprintf(filename, sizeof(filename), kDumpFile, ::GetCurrentProcessId());
FILE* f = fopen(filename, "w");
if (!f)
sym_initialize(::GetCurrentProcess(), NULL, TRUE);
char sym_buf[sizeof(SYMBOL_INFO) + MAX_SYM_NAME * sizeof(TCHAR)];
std::unordered_set<void*> seen;
std::unordered_set<std::string> seen_names;
for (void* sample : samples) {
// Only print the first call of a function.
if (seen.count(sample))
SYMBOL_INFO* symbol = reinterpret_cast<SYMBOL_INFO*>(sym_buf);
symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
symbol->MaxNameLen = MAX_SYM_NAME;
DWORD64 offset = 0;
if (sym_from_addr(::GetCurrentProcess(), reinterpret_cast<DWORD64>(sample),
&offset, symbol)) {
const char* name = symbol->Name;
if (name[0] == '_')
if (seen_names.count(name))
fprintf(f, "%s\n", name);
} // namespace
extern "C" {
void __cyg_profile_func_enter(void* this_fn, void* call_site_unused) {
if (done)
// Get our index for the samples array atomically.
int n = num_samples++;
if (n < kSamplesCapacity) {
samples[n] = this_fn;
if (n + 1 == kSamplesCapacity) {
// This is the final sample; start dumping the samples to a file (on a
// separate thread so as not to disturb the main program).
done = 1;
_beginthread(dump, 0, nullptr);
void __cyg_profile_func_exit(void* this_fn, void* call_site) {}
} // extern "C"