[libc-commits] [libc] [libc] Implement timer_getoverrun in time (PR #234839)

Aman Maurya via libc-commits libc-commits at lists.llvm.org
Fri Oct 23 01:01:39 PDT 2026


https://github.com/amanmaurya92 updated https://github.com/llvm/llvm-project/pull/234839

>From b7ae1fd7c65fb320f74e1d93abd5bcbb9c764a26 Mon Sep 17 00:00:00 2001
From: amanmaurya92 <amanmaurya9209 at gmail.com>
Date: Thu, 22 Oct 2026 23:43:52 +0530
Subject: [PATCH 1/2] [libc] Implement timer_getoverrun in time (#234067)

---
 libc/config/linux/aarch64/entrypoints.txt     |  1 +
 libc/config/linux/riscv/entrypoints.txt       |  1 +
 libc/config/linux/x86_64/entrypoints.txt      |  1 +
 libc/include/time.yaml                        |  6 +++
 .../linux/syscall_wrappers/CMakeLists.txt     | 13 +++++++
 .../linux/syscall_wrappers/timer_getoverrun.h | 38 +++++++++++++++++++
 libc/src/time/CMakeLists.txt                  |  7 ++++
 libc/src/time/linux/CMakeLists.txt            | 15 ++++++++
 libc/src/time/linux/timer_getoverrun.cpp      | 31 +++++++++++++++
 libc/src/time/timer_getoverrun.h              | 26 +++++++++++++
 libc/test/src/time/CMakeLists.txt             |  1 +
 libc/test/src/time/timer_test.cpp             | 17 +++++++++
 12 files changed, 157 insertions(+)
 create mode 100644 libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h
 create mode 100644 libc/src/time/linux/timer_getoverrun.cpp
 create mode 100644 libc/src/time/timer_getoverrun.h

diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index be4d80db3afb37..8ed4aa5036503b 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -1448,6 +1448,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.time.timespec_get
     libc.src.time.timer_create
     libc.src.time.timer_delete
+    libc.src.time.timer_getoverrun
     libc.src.time.timer_gettime
     libc.src.time.timer_settime
 
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index 20e33295bfb206..6b2283823b50ac 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -1638,6 +1638,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.time.timespec_get
     libc.src.time.timer_create
     libc.src.time.timer_delete
+    libc.src.time.timer_getoverrun
     libc.src.time.timer_gettime
     libc.src.time.timer_settime
 
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index 7d7c3ad1e1768d..194c54d7b09dee 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -1664,6 +1664,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.time.timespec_get
     libc.src.time.timer_create
     libc.src.time.timer_delete
+    libc.src.time.timer_getoverrun
     libc.src.time.timer_gettime
     libc.src.time.timer_settime
 
diff --git a/libc/include/time.yaml b/libc/include/time.yaml
index 837b844579d27d..d63dc20e46e587 100644
--- a/libc/include/time.yaml
+++ b/libc/include/time.yaml
@@ -185,6 +185,12 @@ functions:
     return_type: int
     arguments:
       - type: timer_t
+  - name: timer_getoverrun
+    standards:
+      - posix
+    return_type: int
+    arguments:
+      - type: timer_t
   - name: timer_gettime
     standards:
       - posix
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
index 67432985afe067..c7c1f4b9d204f1 100644
--- a/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/CMakeLists.txt
@@ -1603,6 +1603,19 @@ add_header_library(
     libc.src.__support.macros.config
 )
 
+add_header_library(
+  timer_getoverrun
+  HDRS
+    timer_getoverrun.h
+  DEPENDS
+    libc.hdr.types.timer_t
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.__support.common
+    libc.src.__support.error_or
+    libc.src.__support.macros.config
+)
+
 add_header_library(
   timer_gettime
   HDRS
diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h
new file mode 100644
index 00000000000000..b61bb14a499319
--- /dev/null
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h
@@ -0,0 +1,38 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Implementation header for timer_getoverrun syscall wrapper.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_TIMER_GETOVERRUN_H
+#define LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_TIMER_GETOVERRUN_H
+
+#include "hdr/types/timer_t.h"
+#include "src/__support/OSUtil/linux/syscall.h" // For syscall_checked
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+#include <sys/syscall.h> // For syscall numbers
+
+namespace LIBC_NAMESPACE_DECL {
+namespace linux_syscalls {
+
+LIBC_INLINE ErrorOr<int> timer_getoverrun(timer_t timerid) {
+#ifdef SYS_timer_getoverrun
+  return syscall_checked<int>(SYS_timer_getoverrun, timerid);
+#else
+#error "SYS_timer_getoverrun syscall not available."
+#endif
+}
+
+} // namespace linux_syscalls
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC___SUPPORT_OSUTIL_SYSCALL_WRAPPERS_TIMER_GETOVERRUN_H
diff --git a/libc/src/time/CMakeLists.txt b/libc/src/time/CMakeLists.txt
index fcf25bf7e67f1f..40402d602055d8 100644
--- a/libc/src/time/CMakeLists.txt
+++ b/libc/src/time/CMakeLists.txt
@@ -314,6 +314,13 @@ add_entrypoint_object(
     .${LIBC_TARGET_OS}.timer_delete
 )
 
+add_entrypoint_object(
+  timer_getoverrun
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.timer_getoverrun
+)
+
 add_entrypoint_object(
   timer_gettime
   ALIAS
diff --git a/libc/src/time/linux/CMakeLists.txt b/libc/src/time/linux/CMakeLists.txt
index a868c06d73d338..9ecd82a91be832 100644
--- a/libc/src/time/linux/CMakeLists.txt
+++ b/libc/src/time/linux/CMakeLists.txt
@@ -121,6 +121,21 @@ add_entrypoint_object(
     libc.src.errno.errno
 )
 
+add_entrypoint_object(
+  timer_getoverrun
+  SRCS
+    timer_getoverrun.cpp
+  HDRS
+    ../timer_getoverrun.h
+  DEPENDS
+    libc.hdr.types.timer_t
+    libc.src.__support.OSUtil.linux.syscall_wrappers.timer_getoverrun
+    libc.src.__support.common
+    libc.src.__support.libc_errno
+    libc.src.__support.macros.config
+    libc.src.errno.errno
+)
+
 add_entrypoint_object(
   timer_gettime
   SRCS
diff --git a/libc/src/time/linux/timer_getoverrun.cpp b/libc/src/time/linux/timer_getoverrun.cpp
new file mode 100644
index 00000000000000..ef68a7d965d16a
--- /dev/null
+++ b/libc/src/time/linux/timer_getoverrun.cpp
@@ -0,0 +1,31 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Linux implementation of timer_getoverrun function.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/time/timer_getoverrun.h"
+#include "src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h"
+#include "src/__support/common.h"
+#include "src/__support/libc_errno.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, timer_getoverrun, (timer_t timerid)) {
+  auto result = linux_syscalls::timer_getoverrun(timerid);
+  if (!result) {
+    libc_errno = result.error();
+    return -1;
+  }
+  return result.value();
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/time/timer_getoverrun.h b/libc/src/time/timer_getoverrun.h
new file mode 100644
index 00000000000000..5d48185f63b066
--- /dev/null
+++ b/libc/src/time/timer_getoverrun.h
@@ -0,0 +1,26 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// Implementation header for timer_getoverrun function.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_TIME_TIMER_GETOVERRUN_H
+#define LLVM_LIBC_SRC_TIME_TIMER_GETOVERRUN_H
+
+#include "hdr/types/timer_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int timer_getoverrun(timer_t timerid);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_TIME_TIMER_GETOVERRUN_H
diff --git a/libc/test/src/time/CMakeLists.txt b/libc/test/src/time/CMakeLists.txt
index e00d3768ff9358..848d19b5b36de7 100644
--- a/libc/test/src/time/CMakeLists.txt
+++ b/libc/test/src/time/CMakeLists.txt
@@ -179,6 +179,7 @@ add_libc_test(
     libc.src.time.clock_gettime
     libc.src.time.timer_create
     libc.src.time.timer_delete
+    libc.src.time.timer_getoverrun
     libc.src.time.timer_gettime
     libc.src.time.timer_settime
     libc.src.unistd.gettid
diff --git a/libc/test/src/time/timer_test.cpp b/libc/test/src/time/timer_test.cpp
index 01e504ff1b8234..faa33f3c60eb37 100644
--- a/libc/test/src/time/timer_test.cpp
+++ b/libc/test/src/time/timer_test.cpp
@@ -21,6 +21,7 @@
 #include "src/time/clock_gettime.h"
 #include "src/time/timer_create.h"
 #include "src/time/timer_delete.h"
+#include "src/time/timer_getoverrun.h"
 #include "src/time/timer_gettime.h"
 #include "src/time/timer_settime.h"
 #include "src/unistd/gettid.h"
@@ -229,3 +230,19 @@ TEST_F(LlvmLibcTimerTest, GetTimeNullPointer) {
 
   ASSERT_THAT(LIBC_NAMESPACE::timer_delete(timerid), Succeeds(0));
 }
+
+TEST_F(LlvmLibcTimerTest, GetOverrunInvalidTimerId) {
+  ASSERT_THAT(LIBC_NAMESPACE::timer_getoverrun(reinterpret_cast<timer_t>(-1)),
+              Fails(EINVAL));
+}
+
+TEST_F(LlvmLibcTimerTest, GetOverrunInitial) {
+  timer_t timerid;
+  ASSERT_THAT(LIBC_NAMESPACE::timer_create(CLOCK_REALTIME, nullptr, &timerid),
+              Succeeds(0));
+
+  int overrun = LIBC_NAMESPACE::timer_getoverrun(timerid);
+  ASSERT_GE(overrun, 0);
+
+  ASSERT_THAT(LIBC_NAMESPACE::timer_delete(timerid), Succeeds(0));
+}

>From 27d0145292c82371f26a91c52b249d83a1301b5b Mon Sep 17 00:00:00 2001
From: amanmaurya92 <amanmaurya9209 at gmail.com>
Date: Fri, 23 Oct 2026 13:31:12 +0530
Subject: [PATCH 2/2] [libc] Simplify timer_getoverrun syscall wrapper

---
 .../OSUtil/linux/syscall_wrappers/timer_getoverrun.h          | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h b/libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h
index b61bb14a499319..c94313675980e6 100644
--- a/libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h
+++ b/libc/src/__support/OSUtil/linux/syscall_wrappers/timer_getoverrun.h
@@ -25,11 +25,7 @@ namespace LIBC_NAMESPACE_DECL {
 namespace linux_syscalls {
 
 LIBC_INLINE ErrorOr<int> timer_getoverrun(timer_t timerid) {
-#ifdef SYS_timer_getoverrun
   return syscall_checked<int>(SYS_timer_getoverrun, timerid);
-#else
-#error "SYS_timer_getoverrun syscall not available."
-#endif
 }
 
 } // namespace linux_syscalls



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