Squashed 'third_party/gperftools/' content from commit 54505f1
Change-Id: Id02e833828732b0efe7dac722b8485279e67c5fa
git-subtree-dir: third_party/gperftools
git-subtree-split: 54505f1d50c2d1f4676f5e87090b64a117fd980e
diff --git a/src/maybe_threads.cc b/src/maybe_threads.cc
new file mode 100644
index 0000000..6dd0d8d
--- /dev/null
+++ b/src/maybe_threads.cc
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+// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
+// Copyright (c) 2005, 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: Paul Menage <opensource@google.com>
+//
+// Some wrappers for pthread functions so that we can be LD_PRELOADed
+// against non-pthreads apps.
+//
+// This module will behave very strangely if some pthreads functions
+// exist and others don't.
+
+#include "config.h"
+#include <assert.h>
+#include <string.h> // for memcmp
+#include <stdio.h> // for __isthreaded on FreeBSD
+// We don't actually need strings. But including this header seems to
+// stop the compiler trying to short-circuit our pthreads existence
+// tests and claiming that the address of a function is always
+// non-zero. I have no idea why ...
+#include <string>
+#include "maybe_threads.h"
+#include "base/basictypes.h"
+
+// __THROW is defined in glibc systems. It means, counter-intuitively,
+// "This function will never throw an exception." It's an optional
+// optimization tool, but we may need to use it to match glibc prototypes.
+#ifndef __THROW // I guess we're not on a glibc system
+# define __THROW // __THROW is just an optimization, so ok to make it ""
+#endif
+
+// These are the methods we're going to conditionally include.
+extern "C" {
+ int pthread_key_create (pthread_key_t*, void (*)(void*))
+ __THROW ATTRIBUTE_WEAK;
+ int pthread_key_delete (pthread_key_t)
+ __THROW ATTRIBUTE_WEAK;
+ void *pthread_getspecific(pthread_key_t)
+ __THROW ATTRIBUTE_WEAK;
+ int pthread_setspecific(pthread_key_t, const void*)
+ __THROW ATTRIBUTE_WEAK;
+ int pthread_once(pthread_once_t *, void (*)(void))
+ ATTRIBUTE_WEAK;
+}
+
+#define MAX_PERTHREAD_VALS 16
+static void *perftools_pthread_specific_vals[MAX_PERTHREAD_VALS];
+static int next_key;
+
+// NOTE: it's similar to bitcast defined in basic_types.h with
+// exception of ignoring sizes mismatch
+template <typename T1, typename T2>
+static T2 memcpy_cast(const T1 &input) {
+ T2 output;
+ size_t s = sizeof(input);
+ if (sizeof(output) < s) {
+ s = sizeof(output);
+ }
+ memcpy(&output, &input, s);
+ return output;
+}
+
+int perftools_pthread_key_create(pthread_key_t *key,
+ void (*destr_function) (void *)) {
+ if (pthread_key_create) {
+ return pthread_key_create(key, destr_function);
+ } else {
+ assert(next_key < MAX_PERTHREAD_VALS);
+ *key = memcpy_cast<int, pthread_key_t>(next_key++);
+ return 0;
+ }
+}
+
+int perftools_pthread_key_delete(pthread_key_t key) {
+ if (pthread_key_delete) {
+ return pthread_key_delete(key);
+ } else {
+ return 0;
+ }
+}
+
+void *perftools_pthread_getspecific(pthread_key_t key) {
+ if (pthread_getspecific) {
+ return pthread_getspecific(key);
+ } else {
+ return perftools_pthread_specific_vals[memcpy_cast<pthread_key_t, int>(key)];
+ }
+}
+
+int perftools_pthread_setspecific(pthread_key_t key, void *val) {
+ if (pthread_setspecific) {
+ return pthread_setspecific(key, val);
+ } else {
+ perftools_pthread_specific_vals[memcpy_cast<pthread_key_t, int>(key)] = val;
+ return 0;
+ }
+}
+
+
+static pthread_once_t pthread_once_init = PTHREAD_ONCE_INIT;
+int perftools_pthread_once(pthread_once_t *ctl,
+ void (*init_routine) (void)) {
+#ifdef __FreeBSD__
+ // On __FreeBSD__, calling pthread_once on a system that is not
+ // linked with -pthread is silently a noop. :-( Luckily, we have a
+ // workaround: FreeBSD exposes __isthreaded in <stdio.h>, which is
+ // set to 1 when the first thread is spawned. So on those systems,
+ // we can use our own separate pthreads-once mechanism, which is
+ // used until __isthreaded is 1 (which will never be true if the app
+ // is not linked with -pthread).
+ static bool pthread_once_ran_before_threads = false;
+ if (pthread_once_ran_before_threads) {
+ return 0;
+ }
+ if (!__isthreaded) {
+ init_routine();
+ pthread_once_ran_before_threads = true;
+ return 0;
+ }
+#endif
+ if (pthread_once) {
+ return pthread_once(ctl, init_routine);
+ } else {
+ if (memcmp(ctl, &pthread_once_init, sizeof(*ctl)) == 0) {
+ init_routine();
+ ++*(char*)(ctl); // make it so it's no longer equal to init
+ }
+ return 0;
+ }
+}