[libc-commits] [libc] [libc] Add CPU_CLR(_S) macros (PR #204590)
via libc-commits
libc-commits at lists.llvm.org
Thu Jun 18 06:21:32 PDT 2026
llvmorg-github-actions[bot] wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-backend-risc-v
Author: Pavel Labath (labath)
<details>
<summary>Changes</summary>
This patch implements CPU_CLR and CPU_CLR_S macros following the existing CPU_SET pattern. The macro just forwards to an internal entry point.
Assisted by Gemini.
---
Full diff: https://github.com/llvm/llvm-project/pull/204590.diff
11 Files Affected:
- (modified) libc/config/linux/aarch64/entrypoints.txt (+1)
- (modified) libc/config/linux/riscv/entrypoints.txt (+1)
- (modified) libc/config/linux/x86_64/entrypoints.txt (+1)
- (modified) libc/include/llvm-libc-macros/linux/sched-macros.h (+2)
- (modified) libc/include/sched.yaml (+8)
- (modified) libc/src/sched/CMakeLists.txt (+7)
- (modified) libc/src/sched/linux/CMakeLists.txt (+15)
- (added) libc/src/sched/linux/sched_clrcpuset.cpp (+36)
- (added) libc/src/sched/sched_clrcpuset.h (+28)
- (modified) libc/test/src/sched/CMakeLists.txt (+1)
- (modified) libc/test/src/sched/cpu_count_test.cpp (+9)
``````````diff
diff --git a/libc/config/linux/aarch64/entrypoints.txt b/libc/config/linux/aarch64/entrypoints.txt
index 5cddf3dc89799..77bf17b666a14 100644
--- a/libc/config/linux/aarch64/entrypoints.txt
+++ b/libc/config/linux/aarch64/entrypoints.txt
@@ -1101,6 +1101,7 @@ if(LLVM_LIBC_FULL_BUILD)
libc.src.pthread.pthread_setspecific
# sched.h entrypoints
+ libc.src.sched.__sched_clrcpuset
libc.src.sched.__sched_cpualloc
libc.src.sched.__sched_cpufree
libc.src.sched.__sched_getcpucount
diff --git a/libc/config/linux/riscv/entrypoints.txt b/libc/config/linux/riscv/entrypoints.txt
index a57efbb8e464d..5e73718c4fc63 100644
--- a/libc/config/linux/riscv/entrypoints.txt
+++ b/libc/config/linux/riscv/entrypoints.txt
@@ -1234,6 +1234,7 @@ if(LLVM_LIBC_FULL_BUILD)
libc.src.pthread.pthread_setspecific
# sched.h entrypoints
+ libc.src.sched.__sched_clrcpuset
libc.src.sched.__sched_cpualloc
libc.src.sched.__sched_cpufree
libc.src.sched.__sched_getcpucount
diff --git a/libc/config/linux/x86_64/entrypoints.txt b/libc/config/linux/x86_64/entrypoints.txt
index ce88a6749d9dc..eb7d4781936ee 100644
--- a/libc/config/linux/x86_64/entrypoints.txt
+++ b/libc/config/linux/x86_64/entrypoints.txt
@@ -1296,6 +1296,7 @@ if(LLVM_LIBC_FULL_BUILD)
libc.src.pthread.pthread_setspecific
# sched.h entrypoints
+ libc.src.sched.__sched_clrcpuset
libc.src.sched.__sched_cpualloc
libc.src.sched.__sched_cpufree
libc.src.sched.__sched_getcpucount
diff --git a/libc/include/llvm-libc-macros/linux/sched-macros.h b/libc/include/llvm-libc-macros/linux/sched-macros.h
index 539b3530f6e14..42db677b38305 100644
--- a/libc/include/llvm-libc-macros/linux/sched-macros.h
+++ b/libc/include/llvm-libc-macros/linux/sched-macros.h
@@ -25,6 +25,8 @@
#define CPU_SETSIZE __CPU_SETSIZE
#define NCPUBITS __NCPUBITS
+#define CPU_CLR_S(cpu, setsize, set) __sched_clrcpuset(cpu, setsize, set)
+#define CPU_CLR(cpu, set) CPU_CLR_S(cpu, sizeof(cpu_set_t), set)
#define CPU_COUNT_S(setsize, set) __sched_getcpucount(setsize, set)
#define CPU_COUNT(set) CPU_COUNT_S(sizeof(cpu_set_t), set)
#define CPU_ZERO_S(setsize, set) __sched_setcpuzero(setsize, set)
diff --git a/libc/include/sched.yaml b/libc/include/sched.yaml
index afe357e38bf1c..4c657d15fb4f0 100644
--- a/libc/include/sched.yaml
+++ b/libc/include/sched.yaml
@@ -18,6 +18,14 @@ types:
enums: []
objects: []
functions:
+ - name: __sched_clrcpuset
+ standards:
+ - llvm_libc_ext
+ return_type: void
+ arguments:
+ - type: int
+ - type: size_t
+ - type: cpu_set_t *
- name: __sched_cpualloc
standards:
- llvm_libc_ext
diff --git a/libc/src/sched/CMakeLists.txt b/libc/src/sched/CMakeLists.txt
index 3aef41f996962..56ed5c141f1a4 100644
--- a/libc/src/sched/CMakeLists.txt
+++ b/libc/src/sched/CMakeLists.txt
@@ -86,6 +86,13 @@ add_entrypoint_object(
.${LIBC_TARGET_OS}.sched_rr_get_interval
)
+add_entrypoint_object(
+ __sched_clrcpuset
+ ALIAS
+ DEPENDS
+ .${LIBC_TARGET_OS}.__sched_clrcpuset
+)
+
add_entrypoint_object(
__sched_cpualloc
ALIAS
diff --git a/libc/src/sched/linux/CMakeLists.txt b/libc/src/sched/linux/CMakeLists.txt
index b8662c6383e74..f0bb7fcc93b6f 100644
--- a/libc/src/sched/linux/CMakeLists.txt
+++ b/libc/src/sched/linux/CMakeLists.txt
@@ -168,6 +168,21 @@ add_entrypoint_object(
libc.src.errno.errno
)
+add_entrypoint_object(
+ __sched_clrcpuset
+ SRCS
+ sched_clrcpuset.cpp
+ HDRS
+ ../sched_clrcpuset.h
+ DEPENDS
+ libc.src.__support.common
+ libc.src.__support.macros.config
+ libc.src.__support.macros.null_check
+ libc.hdr.sched_macros
+ libc.hdr.types.cpu_set_t
+ libc.hdr.types.size_t
+)
+
add_entrypoint_object(
__sched_cpualloc
SRCS
diff --git a/libc/src/sched/linux/sched_clrcpuset.cpp b/libc/src/sched/linux/sched_clrcpuset.cpp
new file mode 100644
index 0000000000000..7d149b6c88ca2
--- /dev/null
+++ b/libc/src/sched/linux/sched_clrcpuset.cpp
@@ -0,0 +1,36 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 __sched_clrcpuset.
+///
+//===----------------------------------------------------------------------===//
+
+#include "src/sched/sched_clrcpuset.h"
+#include "hdr/sched_macros.h" // NCPUBITS
+#include "hdr/types/cpu_set_t.h"
+#include "hdr/types/size_t.h"
+#include "src/__support/common.h" // LLVM_LIBC_FUNCTION
+#include "src/__support/macros/config.h" // LIBC_NAMESPACE_DECL
+#include "src/__support/macros/null_check.h" // LIBC_CRASH_ON_NULLPTR
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(void, __sched_clrcpuset,
+ (int cpu, const size_t cpuset_size, cpu_set_t *set)) {
+ LIBC_CRASH_ON_NULLPTR(set);
+ if (static_cast<size_t>(cpu) / 8 < cpuset_size) {
+ const size_t element_index = static_cast<size_t>(cpu) / NCPUBITS;
+ const size_t bit_position = static_cast<size_t>(cpu) % NCPUBITS;
+
+ const unsigned long mask = 1UL << bit_position;
+ set->__mask[element_index] &= ~mask;
+ }
+}
+
+} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/sched/sched_clrcpuset.h b/libc/src/sched/sched_clrcpuset.h
new file mode 100644
index 0000000000000..6e6d9e3b77b51
--- /dev/null
+++ b/libc/src/sched/sched_clrcpuset.h
@@ -0,0 +1,28 @@
+//===----------------------------------------------------------------------===//
+//
+// 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 __sched_clrcpuset.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC_SCHED_SCHED_CLRCPUSET_H
+#define LLVM_LIBC_SRC_SCHED_SCHED_CLRCPUSET_H
+
+#include "hdr/types/cpu_set_t.h"
+#include "hdr/types/size_t.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+// for internal use in the CPU_CLR macro
+void __sched_clrcpuset(int cpu, const size_t cpuset_size, cpu_set_t *set);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_SCHED_SCHED_CLRCPUSET_H
diff --git a/libc/test/src/sched/CMakeLists.txt b/libc/test/src/sched/CMakeLists.txt
index b8dbf609ecd0f..f014091f9ace4 100644
--- a/libc/test/src/sched/CMakeLists.txt
+++ b/libc/test/src/sched/CMakeLists.txt
@@ -137,6 +137,7 @@ add_libc_unittest(
libc.src.__support.OSUtil.osutil
libc.src.errno.errno
libc.src.sched.sched_getaffinity
+ libc.src.sched.__sched_clrcpuset
libc.src.sched.__sched_getcpucount
libc.src.sched.__sched_getcpuisset
libc.src.sched.__sched_setcpuset
diff --git a/libc/test/src/sched/cpu_count_test.cpp b/libc/test/src/sched/cpu_count_test.cpp
index 55daa2e421810..e3399b0de7602 100644
--- a/libc/test/src/sched/cpu_count_test.cpp
+++ b/libc/test/src/sched/cpu_count_test.cpp
@@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "src/__support/OSUtil/syscall.h"
+#include "src/sched/sched_clrcpuset.h"
#include "src/sched/sched_getaffinity.h"
#include "src/sched/sched_getcpucount.h"
#include "src/sched/sched_getcpuisset.h"
@@ -46,4 +47,12 @@ TEST_F(LlvmLibcSchedCpuCountTest, CpuSetMacros) {
LIBC_NAMESPACE::CPU_SET(1, &mask);
ASSERT_EQ(LIBC_NAMESPACE::CPU_ISSET(1, &mask), 1);
ASSERT_EQ(LIBC_NAMESPACE::CPU_COUNT(&mask), 1);
+
+ LIBC_NAMESPACE::CPU_CLR(1, &mask);
+ ASSERT_EQ(LIBC_NAMESPACE::CPU_ISSET(1, &mask), 0);
+
+ LIBC_NAMESPACE::CPU_SET_S(1, sizeof(cpu_set_t), &mask);
+ ASSERT_EQ(LIBC_NAMESPACE::CPU_ISSET_S(1, sizeof(cpu_set_t), &mask), 1);
+ LIBC_NAMESPACE::CPU_CLR_S(1, sizeof(cpu_set_t), &mask);
+ ASSERT_EQ(LIBC_NAMESPACE::CPU_ISSET_S(1, sizeof(cpu_set_t), &mask), 0);
}
``````````
</details>
https://github.com/llvm/llvm-project/pull/204590
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