test_guard.pass.cpp
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//===----------------------------- test_guard.cpp -------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "cxxabi.h"
#include <cassert>
#ifndef _LIBCXXABI_HAS_NO_THREADS
#include <thread>
#endif
// Ensure that we initialize each variable once and only once.
namespace test1 {
static int run_count = 0;
int increment() {
++run_count;
return 0;
}
void helper() {
static int a = increment();
((void)a);
}
void test() {
static int a = increment(); ((void)a);
assert(run_count == 1);
static int b = increment(); ((void)b);
assert(run_count == 2);
helper();
assert(run_count == 3);
helper();
assert(run_count == 3);
}
}
// When initialization fails, ensure that we try to initialize it again next
// time.
namespace test2 {
#ifndef LIBCXXABI_HAS_NO_EXCEPTIONS
static int run_count = 0;
int increment() {
++run_count;
throw 0;
}
void helper() {
try {
static int a = increment();
assert(false);
((void)a);
} catch (...) {}
}
void test() {
helper();
assert(run_count == 1);
helper();
assert(run_count == 2);
}
#else
void test() {}
#endif
}
// Check that we can initialize a second value while initializing a first.
namespace test3 {
int zero() {
return 0;
}
int one() {
static int b = zero(); ((void)b);
return 0;
}
void test() {
static int a = one(); ((void)a);
}
}
#ifndef _LIBCXXABI_HAS_NO_THREADS
// A simple thread test of two threads racing to initialize a variable. This
// isn't guaranteed to catch any particular threading problems.
namespace test4 {
static int run_count = 0;
int increment() {
++run_count;
return 0;
}
void helper() {
static int a = increment(); ((void)a);
}
void test() {
std::thread t1(helper), t2(helper);
t1.join();
t2.join();
assert(run_count == 1);
}
}
// Check that we don't re-initialize a static variable even when it's
// encountered from two different threads.
namespace test5 {
static int run_count = 0;
int zero() {
++run_count;
return 0;
}
int one() {
static int b = zero(); ((void)b);
return 0;
}
void another_helper() {
static int a = one(); ((void)a);
}
void helper() {
static int a = one(); ((void)a);
std::thread t(another_helper);
t.join();
}
void test() {
std::thread t(helper);
t.join();
assert(run_count == 1);
}
}
#endif /* _LIBCXXABI_HAS_NO_THREADS */
int main()
{
test1::test();
test2::test();
test3::test();
#ifndef _LIBCXXABI_HAS_NO_THREADS
test4::test();
test5::test();
#endif
}