[libcxx-commits] [libcxx] [libc++] debug semaaphore (PR #180353)
via libcxx-commits
libcxx-commits at lists.llvm.org
Sun Feb 8 00:39:22 PST 2026
https://github.com/huixie90 updated https://github.com/llvm/llvm-project/pull/180353
>From 79cc6e2cc0b253b0a34a3b5ad302341fa943170b Mon Sep 17 00:00:00 2001
From: Hui Xie <hui.xie1990 at gmail.com>
Date: Sat, 7 Feb 2026 16:19:16 +0000
Subject: [PATCH 1/4] [libc++] debug semaaphore
---
.../thread.semaphore/timed.debug.pass.cpp | 84 +++++++++++++++++++
1 file changed, 84 insertions(+)
create mode 100644 libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
diff --git a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
new file mode 100644
index 0000000000000..d7833194927e4
--- /dev/null
+++ b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
@@ -0,0 +1,84 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: no-threads
+// UNSUPPORTED: c++03, c++11, c++14, c++17
+
+// <semaphore>
+
+#include <semaphore>
+#include <thread>
+#include <chrono>
+#include <cassert>
+#include <iostream>
+#include <iomanip>
+
+
+#include "make_test_thread.h"
+#include "test_macros.h"
+
+int main(int, char**)
+{
+ auto const start = std::chrono::steady_clock::now();
+ auto log = [start] ()-> auto& {
+ using namespace std::chrono;
+
+ auto elapsed = steady_clock::now() - start;
+
+ auto hours = duration_cast<std::chrono::hours>(elapsed);
+ elapsed -= hours;
+
+ auto minutes = duration_cast<std::chrono::minutes>(elapsed);
+ elapsed -= minutes;
+
+ auto seconds = duration_cast<std::chrono::seconds>(elapsed);
+ elapsed -= seconds;
+
+ auto milliseconds = duration_cast<std::chrono::milliseconds>(elapsed);
+
+ std::cerr << "["
+ << std::setw(2) << std::setfill('0') << hours.count() << ":"
+ << std::setw(2) << std::setfill('0') << minutes.count() << ":"
+ << std::setw(2) << std::setfill('0') << seconds.count() << "."
+ << std::setw(3) << std::setfill('0') << milliseconds.count()
+ << "] ";
+
+ return std::cerr;
+ };
+
+ std::counting_semaphore<> s(0);
+
+ log() << "try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
+ assert(!s.try_acquire_until(start + std::chrono::milliseconds(250)));
+ log() << "done: try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
+
+ log() << "try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
+ assert(!s.try_acquire_for(std::chrono::milliseconds(250)));
+ log() << "done: try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
+
+ std::thread t = support::make_test_thread([&](){
+ std::this_thread::sleep_for(std::chrono::milliseconds(250));
+ s.release();
+ std::this_thread::sleep_for(std::chrono::milliseconds(250));
+ s.release();
+ });
+
+ log() << "try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
+ assert(s.try_acquire_until(start + std::chrono::seconds(2)));
+ log() << "done: try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
+
+ log() << "try_acquire_for: " << std::chrono::seconds(2) << "\n";
+ assert(s.try_acquire_for(std::chrono::seconds(2)));
+ log() << "done: try_acquire_for: " << std::chrono::seconds(2) << "\n";
+ t.join();
+
+ auto const end = std::chrono::steady_clock::now();
+ assert(end - start < std::chrono::seconds(10));
+
+ return 1;
+}
>From 15caf8d017581b2ac398c6e89c3b9bd9cb81180d Mon Sep 17 00:00:00 2001
From: Hui Xie <hui.xie1990 at gmail.com>
Date: Sat, 7 Feb 2026 16:23:48 +0000
Subject: [PATCH 2/4] code to debug
---
.../thread.semaphore/timed.debug.pass.cpp | 34 ++++++++++++-------
1 file changed, 21 insertions(+), 13 deletions(-)
diff --git a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
index d7833194927e4..904da25a49940 100644
--- a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
@@ -22,13 +22,11 @@
#include "make_test_thread.h"
#include "test_macros.h"
-int main(int, char**)
-{
- auto const start = std::chrono::steady_clock::now();
- auto log = [start] ()-> auto& {
+void test(auto log_start){
+ auto log = [log_start] ()-> auto& {
using namespace std::chrono;
- auto elapsed = steady_clock::now() - start;
+ auto elapsed = steady_clock::now() - log_start;
auto hours = duration_cast<std::chrono::hours>(elapsed);
elapsed -= hours;
@@ -51,15 +49,16 @@ int main(int, char**)
return std::cerr;
};
+ auto const start = std::chrono::steady_clock::now();
std::counting_semaphore<> s(0);
- log() << "try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
+ log() << "start: try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
assert(!s.try_acquire_until(start + std::chrono::milliseconds(250)));
- log() << "done: try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
+ log() << "done: try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
- log() << "try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
+ log() << "start: try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
assert(!s.try_acquire_for(std::chrono::milliseconds(250)));
- log() << "done: try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
+ log() << "done: try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
std::thread t = support::make_test_thread([&](){
std::this_thread::sleep_for(std::chrono::milliseconds(250));
@@ -68,17 +67,26 @@ int main(int, char**)
s.release();
});
- log() << "try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
+ log() << "start: try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
assert(s.try_acquire_until(start + std::chrono::seconds(2)));
- log() << "done: try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
+ log() << "done: try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
- log() << "try_acquire_for: " << std::chrono::seconds(2) << "\n";
+ log() << "start: try_acquire_for: " << std::chrono::seconds(2) << "\n";
assert(s.try_acquire_for(std::chrono::seconds(2)));
- log() << "done: try_acquire_for: " << std::chrono::seconds(2) << "\n";
+ log() << "done: try_acquire_for: " << std::chrono::seconds(2) << "\n";
t.join();
auto const end = std::chrono::steady_clock::now();
assert(end - start < std::chrono::seconds(10));
+}
+
+int main(int, char**)
+{
+ auto const log_start = std::chrono::steady_clock::now();
+ for (auto i = 0; i < 10; ++i) {
+ std::cerr << "=== Iteration " << i << " ===\n";
+ test(log_start);
+ }
return 1;
}
>From 09616457c9c0868806e5a3735ca9706f963e6066 Mon Sep 17 00:00:00 2001
From: Hui Xie <hui.xie1990 at gmail.com>
Date: Sat, 7 Feb 2026 16:44:11 +0000
Subject: [PATCH 3/4] stage3
---
libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
index 904da25a49940..d032145f9824d 100644
--- a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
@@ -88,5 +88,10 @@ int main(int, char**)
test(log_start);
}
+#if defined(_WIN32)
return 1;
+#else
+ return 0;
+#endif
+
}
>From d77abc88ea2e0255caf69a682ef7dd896e1dca56 Mon Sep 17 00:00:00 2001
From: Hui Xie <hui.xie1990 at gmail.com>
Date: Sun, 8 Feb 2026 08:39:09 +0000
Subject: [PATCH 4/4] debug small
---
.../thread.semaphore/timed.debug.pass.cpp | 39 ++++++-------------
1 file changed, 12 insertions(+), 27 deletions(-)
diff --git a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
index d032145f9824d..0294d1fef680d 100644
--- a/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
+++ b/libcxx/test/std/thread/thread.semaphore/timed.debug.pass.cpp
@@ -37,13 +37,13 @@ void test(auto log_start){
auto seconds = duration_cast<std::chrono::seconds>(elapsed);
elapsed -= seconds;
- auto milliseconds = duration_cast<std::chrono::milliseconds>(elapsed);
+ auto nanoseconds = duration_cast<std::chrono::nanoseconds>(elapsed);
std::cerr << "["
<< std::setw(2) << std::setfill('0') << hours.count() << ":"
<< std::setw(2) << std::setfill('0') << minutes.count() << ":"
<< std::setw(2) << std::setfill('0') << seconds.count() << "."
- << std::setw(3) << std::setfill('0') << milliseconds.count()
+ << std::setw(9) << std::setfill('0') << nanoseconds.count()
<< "] ";
return std::cerr;
@@ -52,29 +52,18 @@ void test(auto log_start){
auto const start = std::chrono::steady_clock::now();
std::counting_semaphore<> s(0);
- log() << "start: try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
- assert(!s.try_acquire_until(start + std::chrono::milliseconds(250)));
- log() << "done: try_acquire_until: start + " << std::chrono::milliseconds(250) << "\n";
+ log() << "start: try_acquire_for: " << std::chrono::nanoseconds(1) << "\n";
+ assert(!s.try_acquire_for(std::chrono::nanoseconds(1)));
+ log() << "done: try_acquire_for: " << std::chrono::nanoseconds(1) << "\n";
- log() << "start: try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
- assert(!s.try_acquire_for(std::chrono::milliseconds(250)));
- log() << "done: try_acquire_for: " << std::chrono::milliseconds(250) << "\n";
+ log() << "start: try_acquire_for: " << std::chrono::microseconds(1) << "\n";
+ assert(!s.try_acquire_for(std::chrono::microseconds(1)));
+ log() << "done: try_acquire_for: " << std::chrono::microseconds(1) << "\n";
- std::thread t = support::make_test_thread([&](){
- std::this_thread::sleep_for(std::chrono::milliseconds(250));
- s.release();
- std::this_thread::sleep_for(std::chrono::milliseconds(250));
- s.release();
- });
+ log() << "start: try_acquire_for: " << std::chrono::milliseconds(1) << "\n";
+ assert(!s.try_acquire_for(std::chrono::milliseconds(1)));
+ log() << "done: try_acquire_for: " << std::chrono::milliseconds(1) << "\n";
- log() << "start: try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
- assert(s.try_acquire_until(start + std::chrono::seconds(2)));
- log() << "done: try_acquire_until: start + " << std::chrono::seconds(2) << "\n";
-
- log() << "start: try_acquire_for: " << std::chrono::seconds(2) << "\n";
- assert(s.try_acquire_for(std::chrono::seconds(2)));
- log() << "done: try_acquire_for: " << std::chrono::seconds(2) << "\n";
- t.join();
auto const end = std::chrono::steady_clock::now();
assert(end - start < std::chrono::seconds(10));
@@ -83,15 +72,11 @@ void test(auto log_start){
int main(int, char**)
{
auto const log_start = std::chrono::steady_clock::now();
- for (auto i = 0; i < 10; ++i) {
+ for (auto i = 0; i < 100; ++i) {
std::cerr << "=== Iteration " << i << " ===\n";
test(log_start);
}
-#if defined(_WIN32)
- return 1;
-#else
return 0;
-#endif
}
More information about the libcxx-commits
mailing list