path: root/absl/base/dynamic_annotations.cc

// Copyright 2017 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.

#include <stdlib.h>
#include <string.h>

#include "absl/base/dynamic_annotations.h"

// Compiler-based ThreadSanitizer defines
// DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL = 1
// and provides its own definitions of the functions.

#ifndef DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL
# define DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL 0
#endif

#if DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL == 0 && !defined(__native_client__)

extern "C" {

static int GetRunningOnValgrind(void) {
#ifdef RUNNING_ON_VALGRIND
  if (RUNNING_ON_VALGRIND) return 1;
#endif
  char *running_on_valgrind_str = getenv("RUNNING_ON_VALGRIND");
  if (running_on_valgrind_str) {
    return strcmp(running_on_valgrind_str, "0") != 0;
  }
  return 0;
}

// See the comments in dynamic_annotations.h
int RunningOnValgrind(void) {
  static volatile int running_on_valgrind = -1;
  int local_running_on_valgrind = running_on_valgrind;
  // C doesn't have thread-safe initialization of statics, and we
  // don't want to depend on pthread_once here, so hack it.
  ANNOTATE_BENIGN_RACE(&running_on_valgrind, "safe hack");
  if (local_running_on_valgrind == -1)
    running_on_valgrind = local_running_on_valgrind = GetRunningOnValgrind();
  return local_running_on_valgrind;
}

// See the comments in dynamic_annotations.h
double ValgrindSlowdown(void) {
  // Same initialization hack as in RunningOnValgrind().
  static volatile double slowdown = 0.0;
  double local_slowdown = slowdown;
  ANNOTATE_BENIGN_RACE(&slowdown, "safe hack");
  if (RunningOnValgrind() == 0) {
    return 1.0;
  }
  if (local_slowdown == 0.0) {
    char *env = getenv("VALGRIND_SLOWDOWN");
    slowdown = local_slowdown = env ? atof(env) : 50.0;
  }
  return local_slowdown;
}

}  // extern "C"
#endif  // DYNAMIC_ANNOTATIONS_EXTERNAL_IMPL == 0