[libc-commits] [libc] [libc] add timeout and clock conversion utilities (PR #91905)
Schrodinger ZHU Yifan via libc-commits
libc-commits at lists.llvm.org
Mon May 13 11:27:16 PDT 2024
https://github.com/SchrodingerZhu updated https://github.com/llvm/llvm-project/pull/91905
>From e5a3e11e4a3bab58772a6efee5c779d9b3290ffc Mon Sep 17 00:00:00 2001
From: Schrodinger ZHU Yifan <yifanzhu at rochester.edu>
Date: Sun, 12 May 2024 19:19:26 -0400
Subject: [PATCH 1/5] [libc] add timeout and clock conversion utilities
---
libc/src/__support/time/linux/CMakeLists.txt | 25 +++++++-
.../__support/time/linux/clock_conversion.h | 40 ++++++++++++
.../__support/time/linux/clock_gettime.cpp | 35 -----------
libc/src/__support/time/linux/clock_gettime.h | 24 ++++++-
libc/src/__support/time/linux/timeout.h | 60 ++++++++++++++++++
libc/test/src/__support/CMakeLists.txt | 1 +
libc/test/src/__support/time/CMakeLists.txt | 5 ++
.../src/__support/time/linux/CMakeLists.txt | 8 +++
.../src/__support/time/linux/timeout_test.cpp | 63 +++++++++++++++++++
9 files changed, 221 insertions(+), 40 deletions(-)
create mode 100644 libc/src/__support/time/linux/clock_conversion.h
delete mode 100644 libc/src/__support/time/linux/clock_gettime.cpp
create mode 100644 libc/src/__support/time/linux/timeout.h
create mode 100644 libc/test/src/__support/time/CMakeLists.txt
create mode 100644 libc/test/src/__support/time/linux/CMakeLists.txt
create mode 100644 libc/test/src/__support/time/linux/timeout_test.cpp
diff --git a/libc/src/__support/time/linux/CMakeLists.txt b/libc/src/__support/time/linux/CMakeLists.txt
index f04d550555e19..2e3e3cf439d7c 100644
--- a/libc/src/__support/time/linux/CMakeLists.txt
+++ b/libc/src/__support/time/linux/CMakeLists.txt
@@ -1,9 +1,7 @@
-add_object_library(
+add_header_library(
clock_gettime
HDRS
clock_gettime.h
- SRCS
- clock_gettime.cpp
DEPENDS
libc.include.sys_syscall
libc.hdr.types.struct_timespec
@@ -12,3 +10,24 @@ add_object_library(
libc.src.__support.error_or
libc.src.__support.OSUtil.osutil
)
+
+add_header_library(
+ clock_conversion
+ HDRS
+ clock_conversion.h
+ DEPENDS
+ .clock_gettime
+ libc.src.__support.time.units
+)
+
+add_header_library(
+ timeout
+ HDRS
+ timeout.h
+ DEPENDS
+ .clock_gettime
+ .clock_conversion
+ libc.hdr.types.struct_timespec
+ libc.hdr.time_macros
+ libc.src.__support.CPP.expected
+)
diff --git a/libc/src/__support/time/linux/clock_conversion.h b/libc/src/__support/time/linux/clock_conversion.h
new file mode 100644
index 0000000000000..5d45ec6d1cfea
--- /dev/null
+++ b/libc/src/__support/time/linux/clock_conversion.h
@@ -0,0 +1,40 @@
+//===--- clock conversion linux implementation ------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H
+#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/units.h"
+namespace LIBC_NAMESPACE {
+namespace internal {
+
+LIBC_INLINE timespec convert_clock(timespec input, clockid_t from,
+ clockid_t to) {
+ using namespace time_units;
+ timespec from_time;
+ timespec to_time;
+ timespec output;
+ internal::clock_gettime(from, &from_time);
+ internal::clock_gettime(to, &to_time);
+ output.tv_sec = input.tv_sec - from_time.tv_sec + to_time.tv_sec;
+ output.tv_nsec = input.tv_nsec - from_time.tv_nsec + to_time.tv_nsec;
+
+ if (output.tv_nsec > 1_s_ns) {
+ output.tv_sec++;
+ output.tv_nsec -= 1_s_ns;
+ } else if (output.tv_nsec < 0) {
+ output.tv_sec--;
+ output.tv_nsec += 1_s_ns;
+ }
+ return output;
+}
+
+} // namespace internal
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H
diff --git a/libc/src/__support/time/linux/clock_gettime.cpp b/libc/src/__support/time/linux/clock_gettime.cpp
deleted file mode 100644
index 7f266b282a391..0000000000000
--- a/libc/src/__support/time/linux/clock_gettime.cpp
+++ /dev/null
@@ -1,35 +0,0 @@
-//===--- clock_gettime linux implementation ---------------------*- C++ -*-===//
-//
-// 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 "src/__support/time/linux/clock_gettime.h"
-#include "src/__support/OSUtil/syscall.h"
-#include <sys/syscall.h>
-namespace LIBC_NAMESPACE {
-namespace internal {
-ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts) {
-#if SYS_clock_gettime
- int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime,
- static_cast<long>(clockid),
- reinterpret_cast<long>(ts));
-#elif defined(SYS_clock_gettime64)
- static_assert(
- sizeof(time_t) == sizeof(int64_t),
- "SYS_clock_gettime64 requires struct timespec with 64-bit members.");
- int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime64,
- static_cast<long>(clockid),
- reinterpret_cast<long>(ts));
-#else
-#error "SYS_clock_gettime and SYS_clock_gettime64 syscalls not available."
-#endif
- if (ret < 0)
- return Error(-ret);
- return ret;
-}
-
-} // namespace internal
-} // namespace LIBC_NAMESPACE
diff --git a/libc/src/__support/time/linux/clock_gettime.h b/libc/src/__support/time/linux/clock_gettime.h
index b1572726f6301..4cb6c560fb644 100644
--- a/libc/src/__support/time/linux/clock_gettime.h
+++ b/libc/src/__support/time/linux/clock_gettime.h
@@ -10,14 +10,34 @@
#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_GETTIME_H
#include "hdr/types/clockid_t.h"
#include "hdr/types/struct_timespec.h"
+#include "src/__support/OSUtil/syscall.h"
#include "src/__support/common.h"
-
#include "src/__support/error_or.h"
+#include <sys/syscall.h>
namespace LIBC_NAMESPACE {
namespace internal {
-ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts);
+LIBC_INLINE ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts) {
+#if SYS_clock_gettime
+ int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime,
+ static_cast<long>(clockid),
+ reinterpret_cast<long>(ts));
+#elif defined(SYS_clock_gettime64)
+ static_assert(
+ sizeof(time_t) == sizeof(int64_t),
+ "SYS_clock_gettime64 requires struct timespec with 64-bit members.");
+ int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime64,
+ static_cast<long>(clockid),
+ reinterpret_cast<long>(ts));
+#else
+#error "SYS_clock_gettime and SYS_clock_gettime64 syscalls not available."
+#endif
+ if (ret < 0)
+ return Error(-ret);
+ return ret;
}
+
+} // namespace internal
} // namespace LIBC_NAMESPACE
#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_GETTIME_H
diff --git a/libc/src/__support/time/linux/timeout.h b/libc/src/__support/time/linux/timeout.h
new file mode 100644
index 0000000000000..7d3df936ff10c
--- /dev/null
+++ b/libc/src/__support/time/linux/timeout.h
@@ -0,0 +1,60 @@
+//===--- timeout linux implementation ---------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
+#include "hdr/time_macros.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/CPP/expected.h"
+#include "src/__support/time/linux/clock_conversion.h"
+#include "src/__support/time/units.h"
+namespace LIBC_NAMESPACE {
+namespace internal {
+// We use AbsTimeout to remind ourselves that the timeout is an absolute time.
+// This is a simple wrapper around the timespec struct that also keeps track of
+// whether the time is in realtime or monotonic time.
+
+// This struct is going to be used in timed locks. Pthread generally uses
+// realtime clocks for timeouts. However, due to non-monotoncity, realtime
+// clocks reportedly lead to undesired behaviors. Therefore, we also provide a
+// method to convert the timespec to a monotonic clock relative to the time of
+// function call.
+class AbsTimeout {
+ timespec timeout;
+ bool realtime_flag;
+ LIBC_INLINE constexpr explicit AbsTimeout(timespec ts, bool realtime)
+ : timeout(ts), realtime_flag(realtime) {}
+
+public:
+ enum class Error { Invalid, BeforeEpoch };
+ LIBC_INLINE timespec get_timespec() const { return timeout; }
+ LIBC_INLINE bool is_realtime() const { return realtime_flag; }
+ LIBC_INLINE static constexpr cpp::expected<AbsTimeout, Error>
+ from_timespec(timespec ts, bool realtime) {
+ using namespace time_units;
+ if (ts.tv_nsec < 0 || ts.tv_nsec >= 1_s_ns)
+ return cpp::unexpected<Error>(Error::Invalid);
+
+ // POSIX allows tv_sec to be negative. We interpret this as an expired
+ // timeout.
+ if (ts.tv_sec < 0)
+ return cpp::unexpected<Error>(Error::BeforeEpoch);
+
+ return AbsTimeout{ts, realtime};
+ }
+ LIBC_INLINE void ensure_monotonic() {
+ if (realtime_flag) {
+ timeout = convert_clock(timeout, CLOCK_REALTIME, CLOCK_MONOTONIC);
+ realtime_flag = false;
+ }
+ }
+};
+} // namespace internal
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
diff --git a/libc/test/src/__support/CMakeLists.txt b/libc/test/src/__support/CMakeLists.txt
index 5d1230f5f3a70..8bdc56ee59ccc 100644
--- a/libc/test/src/__support/CMakeLists.txt
+++ b/libc/test/src/__support/CMakeLists.txt
@@ -206,3 +206,4 @@ add_subdirectory(OSUtil)
add_subdirectory(FPUtil)
add_subdirectory(fixed_point)
add_subdirectory(HashTable)
+add_subdirectory(time)
diff --git a/libc/test/src/__support/time/CMakeLists.txt b/libc/test/src/__support/time/CMakeLists.txt
new file mode 100644
index 0000000000000..37062e131acf5
--- /dev/null
+++ b/libc/test/src/__support/time/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_custom_target(libc-support-time-tests)
+
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+ add_subdirectory(${LIBC_TARGET_OS})
+endif()
diff --git a/libc/test/src/__support/time/linux/CMakeLists.txt b/libc/test/src/__support/time/linux/CMakeLists.txt
new file mode 100644
index 0000000000000..8c95667824a9c
--- /dev/null
+++ b/libc/test/src/__support/time/linux/CMakeLists.txt
@@ -0,0 +1,8 @@
+add_libc_test(
+ timeout_test
+ SUITE libc-support-time-tests
+ SRCS timeout_test.cpp
+ DEPENDS
+ libc.src.__support.time.linux.timeout
+ libc.src.__support.CPP.expected
+)
diff --git a/libc/test/src/__support/time/linux/timeout_test.cpp b/libc/test/src/__support/time/linux/timeout_test.cpp
new file mode 100644
index 0000000000000..f2a27dc6d0ab7
--- /dev/null
+++ b/libc/test/src/__support/time/linux/timeout_test.cpp
@@ -0,0 +1,63 @@
+//===-- unit tests for linux's timeout utilities --------------------------===//
+//
+// 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 "src/__support/CPP/expected.h"
+#include "src/__support/time/linux/timeout.h"
+
+#include "test/UnitTest/Test.h"
+
+namespace LIBC_NAMESPACE {
+namespace internal {
+TEST(LlvmLibcSupportLinuxTimeoutTest, NegativeSecond) {
+ timespec ts = {-1, 0};
+ cpp::expected<AbsTimeout, AbsTimeout::Error> result =
+ AbsTimeout::from_timespec(ts, false);
+ ASSERT_FALSE(result.has_value());
+ ASSERT_EQ(result.error(), AbsTimeout::Error::BeforeEpoch);
+}
+TEST(LlvmLibcSupportLinuxTimeoutTest, OverflowNano) {
+ using namespace time_units;
+ timespec ts = {0, 2_s_ns};
+ cpp::expected<AbsTimeout, AbsTimeout::Error> result =
+ AbsTimeout::from_timespec(ts, false);
+ ASSERT_FALSE(result.has_value());
+ ASSERT_EQ(result.error(), AbsTimeout::Error::Invalid);
+}
+TEST(LlvmLibcSupportLinuxTimeoutTest, UnderflowNano) {
+ using namespace time_units;
+ timespec ts = {0, -1};
+ cpp::expected<AbsTimeout, AbsTimeout::Error> result =
+ AbsTimeout::from_timespec(ts, false);
+ ASSERT_FALSE(result.has_value());
+ ASSERT_EQ(result.error(), AbsTimeout::Error::Invalid);
+}
+TEST(LlvmLibcSupportLinuxTimeoutTest, NoChangeIfClockIsMonotonic) {
+ using namespace time_units;
+ timespec ts = {10000, 0};
+ cpp::expected<AbsTimeout, AbsTimeout::Error> result =
+ AbsTimeout::from_timespec(ts, false);
+ ASSERT_TRUE(result.has_value());
+ result->ensure_monotonic();
+ ASSERT_FALSE(result->is_realtime());
+ ASSERT_EQ(result->get_timespec().tv_sec, static_cast<time_t>(10000));
+ ASSERT_EQ(result->get_timespec().tv_nsec, static_cast<time_t>(0));
+}
+TEST(LlvmLibcSupportLinuxTimeoutTest, ValidAfterConversion) {
+ using namespace time_units;
+ timespec ts;
+ internal::clock_gettime(CLOCK_REALTIME, &ts);
+ cpp::expected<AbsTimeout, AbsTimeout::Error> result =
+ AbsTimeout::from_timespec(ts, true);
+ ASSERT_TRUE(result.has_value());
+ result->ensure_monotonic();
+ ASSERT_FALSE(result->is_realtime());
+ ASSERT_TRUE(
+ AbsTimeout::from_timespec(result->get_timespec(), false).has_value());
+}
+} // namespace internal
+} // namespace LIBC_NAMESPACE
>From 8407731e7614a047afd607ac7f48573300be3f0e Mon Sep 17 00:00:00 2001
From: Schrodinger ZHU Yifan <yifanzhu at rochester.edu>
Date: Sun, 12 May 2024 19:36:27 -0400
Subject: [PATCH 2/5] [libc] remove extra using namespace
---
libc/test/src/__support/time/linux/timeout_test.cpp | 3 ---
1 file changed, 3 deletions(-)
diff --git a/libc/test/src/__support/time/linux/timeout_test.cpp b/libc/test/src/__support/time/linux/timeout_test.cpp
index f2a27dc6d0ab7..ff849feeb2847 100644
--- a/libc/test/src/__support/time/linux/timeout_test.cpp
+++ b/libc/test/src/__support/time/linux/timeout_test.cpp
@@ -29,7 +29,6 @@ TEST(LlvmLibcSupportLinuxTimeoutTest, OverflowNano) {
ASSERT_EQ(result.error(), AbsTimeout::Error::Invalid);
}
TEST(LlvmLibcSupportLinuxTimeoutTest, UnderflowNano) {
- using namespace time_units;
timespec ts = {0, -1};
cpp::expected<AbsTimeout, AbsTimeout::Error> result =
AbsTimeout::from_timespec(ts, false);
@@ -37,7 +36,6 @@ TEST(LlvmLibcSupportLinuxTimeoutTest, UnderflowNano) {
ASSERT_EQ(result.error(), AbsTimeout::Error::Invalid);
}
TEST(LlvmLibcSupportLinuxTimeoutTest, NoChangeIfClockIsMonotonic) {
- using namespace time_units;
timespec ts = {10000, 0};
cpp::expected<AbsTimeout, AbsTimeout::Error> result =
AbsTimeout::from_timespec(ts, false);
@@ -48,7 +46,6 @@ TEST(LlvmLibcSupportLinuxTimeoutTest, NoChangeIfClockIsMonotonic) {
ASSERT_EQ(result->get_timespec().tv_nsec, static_cast<time_t>(0));
}
TEST(LlvmLibcSupportLinuxTimeoutTest, ValidAfterConversion) {
- using namespace time_units;
timespec ts;
internal::clock_gettime(CLOCK_REALTIME, &ts);
cpp::expected<AbsTimeout, AbsTimeout::Error> result =
>From 623352b426884f1d672fb4a3fc772113a82a1e51 Mon Sep 17 00:00:00 2001
From: Schrodinger ZHU Yifan <yifanzhu at rochester.edu>
Date: Sun, 12 May 2024 19:38:23 -0400
Subject: [PATCH 3/5] [libc] add whitespace for clarity
---
libc/src/__support/time/linux/clock_conversion.h | 2 ++
libc/src/__support/time/linux/clock_gettime.h | 1 +
libc/src/__support/time/linux/timeout.h | 2 ++
libc/test/src/__support/time/linux/timeout_test.cpp | 1 -
4 files changed, 5 insertions(+), 1 deletion(-)
diff --git a/libc/src/__support/time/linux/clock_conversion.h b/libc/src/__support/time/linux/clock_conversion.h
index 5d45ec6d1cfea..4a7c8ff284849 100644
--- a/libc/src/__support/time/linux/clock_conversion.h
+++ b/libc/src/__support/time/linux/clock_conversion.h
@@ -8,8 +8,10 @@
#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H
#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_CONVERSION_H
+
#include "src/__support/time/linux/clock_gettime.h"
#include "src/__support/time/units.h"
+
namespace LIBC_NAMESPACE {
namespace internal {
diff --git a/libc/src/__support/time/linux/clock_gettime.h b/libc/src/__support/time/linux/clock_gettime.h
index 4cb6c560fb644..bbdde98551abe 100644
--- a/libc/src/__support/time/linux/clock_gettime.h
+++ b/libc/src/__support/time/linux/clock_gettime.h
@@ -8,6 +8,7 @@
#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_GETTIME_H
#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_GETTIME_H
+
#include "hdr/types/clockid_t.h"
#include "hdr/types/struct_timespec.h"
#include "src/__support/OSUtil/syscall.h"
diff --git a/libc/src/__support/time/linux/timeout.h b/libc/src/__support/time/linux/timeout.h
index 7d3df936ff10c..266211ace2e6b 100644
--- a/libc/src/__support/time/linux/timeout.h
+++ b/libc/src/__support/time/linux/timeout.h
@@ -8,11 +8,13 @@
#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
+
#include "hdr/time_macros.h"
#include "hdr/types/struct_timespec.h"
#include "src/__support/CPP/expected.h"
#include "src/__support/time/linux/clock_conversion.h"
#include "src/__support/time/units.h"
+
namespace LIBC_NAMESPACE {
namespace internal {
// We use AbsTimeout to remind ourselves that the timeout is an absolute time.
diff --git a/libc/test/src/__support/time/linux/timeout_test.cpp b/libc/test/src/__support/time/linux/timeout_test.cpp
index ff849feeb2847..8c638dd7bb777 100644
--- a/libc/test/src/__support/time/linux/timeout_test.cpp
+++ b/libc/test/src/__support/time/linux/timeout_test.cpp
@@ -8,7 +8,6 @@
#include "src/__support/CPP/expected.h"
#include "src/__support/time/linux/timeout.h"
-
#include "test/UnitTest/Test.h"
namespace LIBC_NAMESPACE {
>From 038fd55301767ec3af7177012becf354d503dbca Mon Sep 17 00:00:00 2001
From: Schrodinger ZHU Yifan <yifanzhu at rochester.edu>
Date: Mon, 13 May 2024 09:52:13 -0400
Subject: [PATCH 4/5] separate timeout definition and use it in futex
---
.../__support/threads/linux/CMakeLists.txt | 2 +-
.../src/__support/threads/linux/futex_utils.h | 11 ++--
libc/src/__support/time/linux/CMakeLists.txt | 12 +++-
libc/src/__support/time/linux/timeout.h | 38 ++----------
libc/src/__support/time/linux/timeout_basic.h | 60 +++++++++++++++++++
5 files changed, 81 insertions(+), 42 deletions(-)
create mode 100644 libc/src/__support/time/linux/timeout_basic.h
diff --git a/libc/src/__support/threads/linux/CMakeLists.txt b/libc/src/__support/threads/linux/CMakeLists.txt
index 9bee30206f1b9..eec1421629b22 100644
--- a/libc/src/__support/threads/linux/CMakeLists.txt
+++ b/libc/src/__support/threads/linux/CMakeLists.txt
@@ -19,7 +19,7 @@ add_header_library(
libc.src.__support.CPP.atomic
libc.src.__support.CPP.limits
libc.src.__support.CPP.optional
- libc.hdr.types.struct_timespec
+ libc.src.__support.time.linux.timeout_basic
)
add_header_library(
diff --git a/libc/src/__support/threads/linux/futex_utils.h b/libc/src/__support/threads/linux/futex_utils.h
index 1fbce4f7bf438..45c725dc008f4 100644
--- a/libc/src/__support/threads/linux/futex_utils.h
+++ b/libc/src/__support/threads/linux/futex_utils.h
@@ -9,23 +9,20 @@
#ifndef LLVM_LIBC_SRC___SUPPORT_THREADS_LINUX_FUTEX_UTILS_H
#define LLVM_LIBC_SRC___SUPPORT_THREADS_LINUX_FUTEX_UTILS_H
-#include "hdr/types/struct_timespec.h"
#include "src/__support/CPP/atomic.h"
#include "src/__support/CPP/limits.h"
#include "src/__support/CPP/optional.h"
#include "src/__support/OSUtil/syscall.h"
#include "src/__support/macros/attributes.h"
#include "src/__support/threads/linux/futex_word.h"
+#include "src/__support/time/linux/timeout_basic.h"
#include <linux/errno.h>
#include <linux/futex.h>
namespace LIBC_NAMESPACE {
class Futex : public cpp::Atomic<FutexWordType> {
public:
- struct Timeout {
- timespec abs_time;
- bool is_realtime;
- };
+ using Timeout = internal::AbsTimeout;
LIBC_INLINE constexpr Futex(FutexWordType value)
: cpp::Atomic<FutexWordType>(value) {}
LIBC_INLINE Futex &operator=(FutexWordType value) {
@@ -37,7 +34,7 @@ class Futex : public cpp::Atomic<FutexWordType> {
bool is_shared = false) {
// use bitset variants to enforce abs_time
uint32_t op = is_shared ? FUTEX_WAIT_BITSET : FUTEX_WAIT_BITSET_PRIVATE;
- if (timeout && timeout->is_realtime) {
+ if (timeout && timeout->is_realtime()) {
op |= FUTEX_CLOCK_REALTIME;
}
for (;;) {
@@ -49,7 +46,7 @@ class Futex : public cpp::Atomic<FutexWordType> {
/* futex address */ this,
/* futex operation */ op,
/* expected value */ expected,
- /* timeout */ timeout ? &timeout->abs_time : nullptr,
+ /* timeout */ timeout ? &timeout->get_timespec() : nullptr,
/* ignored */ nullptr,
/* bitset */ FUTEX_BITSET_MATCH_ANY);
diff --git a/libc/src/__support/time/linux/CMakeLists.txt b/libc/src/__support/time/linux/CMakeLists.txt
index 2e3e3cf439d7c..25aa48f3b6f36 100644
--- a/libc/src/__support/time/linux/CMakeLists.txt
+++ b/libc/src/__support/time/linux/CMakeLists.txt
@@ -20,6 +20,15 @@ add_header_library(
libc.src.__support.time.units
)
+add_header_library(
+ timeout_basic
+ HDRS
+ timeout_basic.h
+ DEPENDS
+ libc.hdr.types.struct_timespec
+ libc.src.__support.time.units
+)
+
add_header_library(
timeout
HDRS
@@ -27,7 +36,6 @@ add_header_library(
DEPENDS
.clock_gettime
.clock_conversion
- libc.hdr.types.struct_timespec
- libc.hdr.time_macros
+ .timeout_basic
libc.src.__support.CPP.expected
)
diff --git a/libc/src/__support/time/linux/timeout.h b/libc/src/__support/time/linux/timeout.h
index 266211ace2e6b..f5f3e8dc65771 100644
--- a/libc/src/__support/time/linux/timeout.h
+++ b/libc/src/__support/time/linux/timeout.h
@@ -10,10 +10,8 @@
#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
#include "hdr/time_macros.h"
-#include "hdr/types/struct_timespec.h"
-#include "src/__support/CPP/expected.h"
#include "src/__support/time/linux/clock_conversion.h"
-#include "src/__support/time/units.h"
+#include "src/__support/time/linux/timeout_basic.h"
namespace LIBC_NAMESPACE {
namespace internal {
@@ -26,36 +24,12 @@ namespace internal {
// clocks reportedly lead to undesired behaviors. Therefore, we also provide a
// method to convert the timespec to a monotonic clock relative to the time of
// function call.
-class AbsTimeout {
- timespec timeout;
- bool realtime_flag;
- LIBC_INLINE constexpr explicit AbsTimeout(timespec ts, bool realtime)
- : timeout(ts), realtime_flag(realtime) {}
-
-public:
- enum class Error { Invalid, BeforeEpoch };
- LIBC_INLINE timespec get_timespec() const { return timeout; }
- LIBC_INLINE bool is_realtime() const { return realtime_flag; }
- LIBC_INLINE static constexpr cpp::expected<AbsTimeout, Error>
- from_timespec(timespec ts, bool realtime) {
- using namespace time_units;
- if (ts.tv_nsec < 0 || ts.tv_nsec >= 1_s_ns)
- return cpp::unexpected<Error>(Error::Invalid);
-
- // POSIX allows tv_sec to be negative. We interpret this as an expired
- // timeout.
- if (ts.tv_sec < 0)
- return cpp::unexpected<Error>(Error::BeforeEpoch);
-
- return AbsTimeout{ts, realtime};
- }
- LIBC_INLINE void ensure_monotonic() {
- if (realtime_flag) {
- timeout = convert_clock(timeout, CLOCK_REALTIME, CLOCK_MONOTONIC);
- realtime_flag = false;
- }
+LIBC_INLINE void AbsTimeout::ensure_monotonic() {
+ if (realtime_flag) {
+ timeout = convert_clock(timeout, CLOCK_REALTIME, CLOCK_MONOTONIC);
+ realtime_flag = false;
}
-};
+}
} // namespace internal
} // namespace LIBC_NAMESPACE
diff --git a/libc/src/__support/time/linux/timeout_basic.h b/libc/src/__support/time/linux/timeout_basic.h
new file mode 100644
index 0000000000000..68d3456366aa3
--- /dev/null
+++ b/libc/src/__support/time/linux/timeout_basic.h
@@ -0,0 +1,60 @@
+//===--- timeout linux implementation (type-only) ---------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_BASIC_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_BASIC_H
+
+#include "hdr/time_macros.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/CPP/expected.h"
+#include "src/__support/time/units.h"
+
+namespace LIBC_NAMESPACE {
+namespace internal {
+// We use AbsTimeout to remind ourselves that the timeout is an absolute time.
+// This is a simple wrapper around the timespec struct that also keeps track of
+// whether the time is in realtime or monotonic time.
+
+// This struct is going to be used in timed locks. Pthread generally uses
+// realtime clocks for timeouts. However, due to non-monotoncity, realtime
+// clocks reportedly lead to undesired behaviors. Therefore, we also provide a
+// method to convert the timespec to a monotonic clock relative to the time of
+// function call.
+class AbsTimeout {
+ timespec timeout;
+ bool realtime_flag;
+ LIBC_INLINE constexpr explicit AbsTimeout(timespec ts, bool realtime)
+ : timeout(ts), realtime_flag(realtime) {}
+
+public:
+ enum class Error { Invalid, BeforeEpoch };
+ LIBC_INLINE const timespec &get_timespec() const { return timeout; }
+ LIBC_INLINE bool is_realtime() const { return realtime_flag; }
+ LIBC_INLINE static constexpr cpp::expected<AbsTimeout, Error>
+ from_timespec(timespec ts, bool realtime) {
+ using namespace time_units;
+ if (ts.tv_nsec < 0 || ts.tv_nsec >= 1_s_ns)
+ return cpp::unexpected<Error>(Error::Invalid);
+
+ // POSIX allows tv_sec to be negative. We interpret this as an expired
+ // timeout.
+ if (ts.tv_sec < 0)
+ return cpp::unexpected<Error>(Error::BeforeEpoch);
+
+ return AbsTimeout{ts, realtime};
+ }
+ // The implementation of this function is separated to timeout.h.
+ // This function pulls in the dependency to clock_conversion.h,
+ // which may transitively depend on vDSO hence futex. However, this structure
+ // would be passed to futex, so we need to avoid cyclic dependencies.
+ LIBC_INLINE void ensure_monotonic();
+};
+} // namespace internal
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_BASIC_H
>From fd3aceaa59985318105fbb1ecf084919917ef043 Mon Sep 17 00:00:00 2001
From: Schrodinger ZHU Yifan <yifanzhu at rochester.edu>
Date: Mon, 13 May 2024 14:26:59 -0400
Subject: [PATCH 5/5] address CR
---
.../__support/threads/linux/CMakeLists.txt | 2 +-
.../src/__support/threads/linux/futex_utils.h | 2 +-
libc/src/__support/time/linux/CMakeLists.txt | 13 +++---
.../linux/{timeout_basic.h => abs_timeout.h} | 19 ++------
libc/src/__support/time/linux/monotonicity.h | 43 +++++++++++++++++++
libc/src/__support/time/linux/timeout.h | 36 ----------------
.../src/__support/time/linux/CMakeLists.txt | 3 +-
.../src/__support/time/linux/timeout_test.cpp | 7 +--
8 files changed, 62 insertions(+), 63 deletions(-)
rename libc/src/__support/time/linux/{timeout_basic.h => abs_timeout.h} (64%)
create mode 100644 libc/src/__support/time/linux/monotonicity.h
delete mode 100644 libc/src/__support/time/linux/timeout.h
diff --git a/libc/src/__support/threads/linux/CMakeLists.txt b/libc/src/__support/threads/linux/CMakeLists.txt
index eec1421629b22..d3353f6b3ff8c 100644
--- a/libc/src/__support/threads/linux/CMakeLists.txt
+++ b/libc/src/__support/threads/linux/CMakeLists.txt
@@ -19,7 +19,7 @@ add_header_library(
libc.src.__support.CPP.atomic
libc.src.__support.CPP.limits
libc.src.__support.CPP.optional
- libc.src.__support.time.linux.timeout_basic
+ libc.src.__support.time.linux.abs_timeout
)
add_header_library(
diff --git a/libc/src/__support/threads/linux/futex_utils.h b/libc/src/__support/threads/linux/futex_utils.h
index 45c725dc008f4..e40ade8e709b1 100644
--- a/libc/src/__support/threads/linux/futex_utils.h
+++ b/libc/src/__support/threads/linux/futex_utils.h
@@ -15,7 +15,7 @@
#include "src/__support/OSUtil/syscall.h"
#include "src/__support/macros/attributes.h"
#include "src/__support/threads/linux/futex_word.h"
-#include "src/__support/time/linux/timeout_basic.h"
+#include "src/__support/time/linux/abs_timeout.h"
#include <linux/errno.h>
#include <linux/futex.h>
diff --git a/libc/src/__support/time/linux/CMakeLists.txt b/libc/src/__support/time/linux/CMakeLists.txt
index 25aa48f3b6f36..dc1133f2f65b9 100644
--- a/libc/src/__support/time/linux/CMakeLists.txt
+++ b/libc/src/__support/time/linux/CMakeLists.txt
@@ -21,21 +21,22 @@ add_header_library(
)
add_header_library(
- timeout_basic
+ abs_timeout
HDRS
- timeout_basic.h
+ abs_timeout.h
DEPENDS
libc.hdr.types.struct_timespec
libc.src.__support.time.units
+ libc.src.__support.CPP.expected
)
add_header_library(
- timeout
+ monotonicity
HDRS
- timeout.h
+ monotonicity.h
DEPENDS
.clock_gettime
.clock_conversion
- .timeout_basic
- libc.src.__support.CPP.expected
+ .abs_timeout
+ libc.hdr.time_macros
)
diff --git a/libc/src/__support/time/linux/timeout_basic.h b/libc/src/__support/time/linux/abs_timeout.h
similarity index 64%
rename from libc/src/__support/time/linux/timeout_basic.h
rename to libc/src/__support/time/linux/abs_timeout.h
index 68d3456366aa3..6e5e59b32b7ad 100644
--- a/libc/src/__support/time/linux/timeout_basic.h
+++ b/libc/src/__support/time/linux/abs_timeout.h
@@ -1,4 +1,4 @@
-//===--- timeout linux implementation (type-only) ---------------*- C++ -*-===//
+//===--- Linux absolute timeout ---------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
@@ -6,8 +6,8 @@
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_BASIC_H
-#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_BASIC_H
+#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H
#include "hdr/time_macros.h"
#include "hdr/types/struct_timespec.h"
@@ -19,12 +19,6 @@ namespace internal {
// We use AbsTimeout to remind ourselves that the timeout is an absolute time.
// This is a simple wrapper around the timespec struct that also keeps track of
// whether the time is in realtime or monotonic time.
-
-// This struct is going to be used in timed locks. Pthread generally uses
-// realtime clocks for timeouts. However, due to non-monotoncity, realtime
-// clocks reportedly lead to undesired behaviors. Therefore, we also provide a
-// method to convert the timespec to a monotonic clock relative to the time of
-// function call.
class AbsTimeout {
timespec timeout;
bool realtime_flag;
@@ -48,13 +42,8 @@ class AbsTimeout {
return AbsTimeout{ts, realtime};
}
- // The implementation of this function is separated to timeout.h.
- // This function pulls in the dependency to clock_conversion.h,
- // which may transitively depend on vDSO hence futex. However, this structure
- // would be passed to futex, so we need to avoid cyclic dependencies.
- LIBC_INLINE void ensure_monotonic();
};
} // namespace internal
} // namespace LIBC_NAMESPACE
-#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_BASIC_H
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_ABS_TIMEOUT_H
diff --git a/libc/src/__support/time/linux/monotonicity.h b/libc/src/__support/time/linux/monotonicity.h
new file mode 100644
index 0000000000000..e413275430dd1
--- /dev/null
+++ b/libc/src/__support/time/linux/monotonicity.h
@@ -0,0 +1,43 @@
+//===--- timeout linux implementation ---------------------------*- C++ -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_MONOTONICITY_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_MONOTONICITY_H
+
+#include "hdr/time_macros.h"
+#include "src/__support/libc_assert.h"
+#include "src/__support/time/linux/abs_timeout.h"
+#include "src/__support/time/linux/clock_conversion.h"
+namespace LIBC_NAMESPACE {
+namespace internal {
+// This function is separated from abs_timeout.
+// This function pulls in the dependency to clock_conversion.h,
+// which may transitively depend on vDSO hence futex. However, this structure
+// would be passed to futex, so we need to avoid cyclic dependencies.
+// This function is going to be used in timed locks. Pthread generally uses
+// realtime clocks for timeouts. However, due to non-monotoncity, realtime
+// clocks reportedly lead to undesired behaviors. Therefore, we also provide a
+// method to convert the timespec to a monotonic clock relative to the time of
+// function call.
+LIBC_INLINE void ensure_monotonicity(AbsTimeout &timeout) {
+ if (timeout.is_realtime()) {
+ auto res = AbsTimeout::from_timespec(
+ convert_clock(timeout.get_timespec(), CLOCK_REALTIME, CLOCK_MONOTONIC),
+ false);
+
+ LIBC_ASSERT(res.has_value());
+ if (!res.has_value())
+ __builtin_unreachable();
+
+ timeout = *res;
+ }
+}
+} // namespace internal
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_MONOTONICITY_H
diff --git a/libc/src/__support/time/linux/timeout.h b/libc/src/__support/time/linux/timeout.h
deleted file mode 100644
index f5f3e8dc65771..0000000000000
--- a/libc/src/__support/time/linux/timeout.h
+++ /dev/null
@@ -1,36 +0,0 @@
-//===--- timeout linux implementation ---------------------------*- C++ -*-===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-
-#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
-#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
-
-#include "hdr/time_macros.h"
-#include "src/__support/time/linux/clock_conversion.h"
-#include "src/__support/time/linux/timeout_basic.h"
-
-namespace LIBC_NAMESPACE {
-namespace internal {
-// We use AbsTimeout to remind ourselves that the timeout is an absolute time.
-// This is a simple wrapper around the timespec struct that also keeps track of
-// whether the time is in realtime or monotonic time.
-
-// This struct is going to be used in timed locks. Pthread generally uses
-// realtime clocks for timeouts. However, due to non-monotoncity, realtime
-// clocks reportedly lead to undesired behaviors. Therefore, we also provide a
-// method to convert the timespec to a monotonic clock relative to the time of
-// function call.
-LIBC_INLINE void AbsTimeout::ensure_monotonic() {
- if (realtime_flag) {
- timeout = convert_clock(timeout, CLOCK_REALTIME, CLOCK_MONOTONIC);
- realtime_flag = false;
- }
-}
-} // namespace internal
-} // namespace LIBC_NAMESPACE
-
-#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_TIMEOUT_H
diff --git a/libc/test/src/__support/time/linux/CMakeLists.txt b/libc/test/src/__support/time/linux/CMakeLists.txt
index 8c95667824a9c..3174986283dd8 100644
--- a/libc/test/src/__support/time/linux/CMakeLists.txt
+++ b/libc/test/src/__support/time/linux/CMakeLists.txt
@@ -3,6 +3,7 @@ add_libc_test(
SUITE libc-support-time-tests
SRCS timeout_test.cpp
DEPENDS
- libc.src.__support.time.linux.timeout
+ libc.src.__support.time.linux.abs_timeout
+ libc.src.__support.time.linux.monotonicity
libc.src.__support.CPP.expected
)
diff --git a/libc/test/src/__support/time/linux/timeout_test.cpp b/libc/test/src/__support/time/linux/timeout_test.cpp
index 8c638dd7bb777..711dc0d3c944f 100644
--- a/libc/test/src/__support/time/linux/timeout_test.cpp
+++ b/libc/test/src/__support/time/linux/timeout_test.cpp
@@ -7,7 +7,8 @@
//===----------------------------------------------------------------------===//
#include "src/__support/CPP/expected.h"
-#include "src/__support/time/linux/timeout.h"
+#include "src/__support/time/linux/abs_timeout.h"
+#include "src/__support/time/linux/monotonicity.h"
#include "test/UnitTest/Test.h"
namespace LIBC_NAMESPACE {
@@ -39,7 +40,7 @@ TEST(LlvmLibcSupportLinuxTimeoutTest, NoChangeIfClockIsMonotonic) {
cpp::expected<AbsTimeout, AbsTimeout::Error> result =
AbsTimeout::from_timespec(ts, false);
ASSERT_TRUE(result.has_value());
- result->ensure_monotonic();
+ ensure_monotonicity(*result);
ASSERT_FALSE(result->is_realtime());
ASSERT_EQ(result->get_timespec().tv_sec, static_cast<time_t>(10000));
ASSERT_EQ(result->get_timespec().tv_nsec, static_cast<time_t>(0));
@@ -50,7 +51,7 @@ TEST(LlvmLibcSupportLinuxTimeoutTest, ValidAfterConversion) {
cpp::expected<AbsTimeout, AbsTimeout::Error> result =
AbsTimeout::from_timespec(ts, true);
ASSERT_TRUE(result.has_value());
- result->ensure_monotonic();
+ ensure_monotonicity(*result);
ASSERT_FALSE(result->is_realtime());
ASSERT_TRUE(
AbsTimeout::from_timespec(result->get_timespec(), false).has_value());
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