feat: implement CPU_ISSET[_S] macro and fix CPU_SET[_S] macro

Author: krishna2803

libc/config/linux/aarch64/entrypoints.txt

@@ -912,6 +912,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.sched.__sched_getcpucount
     libc.src.sched.__sched_setcpuzero
     libc.src.sched.__sched_setcpuset
+    libc.src.sched.__sched_getcpuisset
 
     # strings.h entrypoints
     libc.src.strings.strcasecmp_l

libc/config/linux/riscv/entrypoints.txt

@@ -860,6 +860,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.sched.__sched_getcpucount
     libc.src.sched.__sched_setcpuzero
     libc.src.sched.__sched_setcpuset
+    libc.src.sched.__sched_getcpuisset
 
     # setjmp.h entrypoints
     libc.src.setjmp.longjmp

libc/config/linux/x86_64/entrypoints.txt

@@ -1030,6 +1030,7 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.sched.__sched_getcpucount
     libc.src.sched.__sched_setcpuzero
     libc.src.sched.__sched_setcpuset
+    libc.src.sched.__sched_getcpuisset
 
     # setjmp.h entrypoints
     libc.src.setjmp.longjmp

libc/include/llvm-libc-macros/linux/sched-macros.h

@@ -29,7 +29,9 @@
 #define CPU_COUNT(set) CPU_COUNT_S(sizeof(cpu_set_t), set)
 #define CPU_ZERO_S(setsize, set) __sched_setcpuzero(setsize, set)
 #define CPU_ZERO(set) CPU_ZERO_S(sizeof(cpu_set_t), set)
-#define CPU_SET_S(setsize, set) __sched_setcpuset(setsize, set)
-#define CPU_SET(setsize, set) CPU_SET_S(sizeof(cpt_set_t), set)
+#define CPU_SET_S(cpu, setsize, set) __sched_setcpuset(cpu, setsize, set)
+#define CPU_SET(cpu, setsize, set) CPU_SET_S(cpu, sizeof(cpt_set_t), set)
+#define CPU_ISSET_S(cpu, setsize, set) __sched_getcpuisset(cpu, setsize, set)
+#define CPU_ISSET(cpu, setsize, set) CPU_ISSET_S(cpu, sizeof(cpt_set_t), set)
 
 #endif // LLVM_LIBC_MACROS_LINUX_SCHED_MACROS_H

libc/src/sched/CMakeLists.txt

@@ -92,3 +92,10 @@ add_entrypoint_object(
   DEPENDS
     .${LIBC_TARGET_OS}.__sched_setcpuset
 )
+
+add_entrypoint_object(
+  __sched_getcpuisset
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.__sched_getcpuisset
+)

libc/src/sched/linux/CMakeLists.txt

@@ -154,6 +154,19 @@ add_entrypoint_object(
   HDRS
     ../sched_setcpuset.h
   DEPENDS
+    libc.hdr.sched_macros
+    libc.hdr.types.cpu_set_t
+    libc.hdr.types.size_t
+)
+
+add_entrypoint_object(
+  __sched_getcpuisset
+  SRCS
+    sched_getcpuisset.cpp
+  HDRS
+    ../sched_getcpuisset.h
+  DEPENDS
+    libc.hdr.sched_macros
     libc.hdr.types.cpu_set_t
     libc.hdr.types.size_t
 )

libc/src/sched/linux/sched_getcpuisset.cpp

@@ -0,0 +1,33 @@
+//===-- Implementation of sched_getcpuisset -------------------------------===//
+//
+// 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/sched/sched_getcpuisset.h"
+
+#include "src/__support/common.h"        // LLVM_LIBC_FUNCTION
+#include "src/__support/macros/config.h" // LIBC_NAMESPACE_DECL
+
+#include "hdr/sched_macros.h" // NCPUBITS
+#include "hdr/types/cpu_set_t.h"
+#include "hdr/types/size_t.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+LLVM_LIBC_FUNCTION(int, __sched_getcpuisset,
+                   (int cpu, const size_t cpuset_size, cpu_set_t *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;
+    return set->__mask[element_index] & mask;
+  }
+
+  return 0;
+}
+
+} // namespace LIBC_NAMESPACE_DECL

libc/src/sched/linux/sched_setcpuset.cpp

@@ -24,7 +24,7 @@ LLVM_LIBC_FUNCTION(void, __sched_setcpuset,
     const size_t bit_position = static_cast<size_t>(cpu) % NCPUBITS;
 
     const unsigned long mask = 1UL << bit_position;
-    set->__bits[element_index] |= mask;
+    set->__mask[element_index] |= mask;
   }
 }
 

libc/src/sched/sched_getcpuisset.h

@@ -0,0 +1,24 @@
+//===-- Implementation header for sched_getcpuisset -------------*- 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_SCHED_SCHED_GETCPUISSET_H
+#define LLVM_LIBC_SRC_SCHED_SCHED_GETCPUISSET_H
+
+#include "src/__support/macros/config.h" // LIBC_NAMESPACE_DECL
+
+#include "hdr/types/cpu_set_t.h"
+#include "hdr/types/size_t.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+// for internal use in the CPU_ISSET macro
+int __sched_getcpuisset(int cpu, const size_t cpuset_size, cpu_set_t *set);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_SCHED_SCHED_GETCPUISSET_H