[libc-commits] [libc] [libc] Implement clone(2) and use it in thread spawning (PR #224257)

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``````````bash
git-clang-format --diff origin/main HEAD --extensions cpp,h -- libc/src/__support/OSUtil/linux/syscall_wrappers/aarch64/clone.h libc/src/__support/OSUtil/linux/syscall_wrappers/clone.h libc/src/__support/OSUtil/linux/syscall_wrappers/riscv/clone.h libc/src/__support/OSUtil/linux/syscall_wrappers/x86_64/clone.h libc/src/sched/clone.h libc/src/sched/linux/clone.cpp libc/test/src/sched/linux/clone_test.cpp libc/src/__support/threads/linux/thread.cpp --diff_from_common_commit
``````````

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``````````diff
diff --git a/libc/src/__support/threads/linux/thread.cpp b/libc/src/__support/threads/linux/thread.cpp
index 6582e599e..df294e2e4 100644
--- a/libc/src/__support/threads/linux/thread.cpp
+++ b/libc/src/__support/threads/linux/thread.cpp
@@ -208,8 +208,8 @@ int Thread::run(ThreadStyle style, ThreadRunner runner, void *arg, void *stack,
   // stack we pass to the clone syscall. Thread initialization structures
   // (StartArgs, ThreadAttributes, and the clear_tid Futex) are allocated on
   // the new thread's stack memory so their lifetime is managed with the stack
-  // without requiring heap allocation. A pointer to StartArgs is passed directly
-  // to start_thread via the clone syscall wrapper's argument.
+  // without requiring heap allocation. A pointer to StartArgs is passed
+  // directly to start_thread via the clone syscall wrapper's argument.
 
   static constexpr size_t INTERNAL_STACK_DATA_SIZE =
       sizeof(StartArgs) + sizeof(ThreadAttributes) + sizeof(Futex);
diff --git a/libc/test/src/sched/linux/clone_test.cpp b/libc/test/src/sched/linux/clone_test.cpp
index 6ed553692..9a0430a97 100644
--- a/libc/test/src/sched/linux/clone_test.cpp
+++ b/libc/test/src/sched/linux/clone_test.cpp
@@ -156,8 +156,7 @@ TEST_F(LlvmLibcSchedCloneTest, ChildTidSeparateVm) {
   TidArgs args;
   args.parent_tid = LIBC_NAMESPACE::gettid();
   void *stack_top = get_child_stack_top();
-  pid_t pid =
-      LIBC_NAMESPACE::clone(check_tid_child, stack_top, SIGCHLD, &args);
+  pid_t pid = LIBC_NAMESPACE::clone(check_tid_child, stack_top, SIGCHLD, &args);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(pid, 0);
 
@@ -174,8 +173,8 @@ TEST_F(LlvmLibcSchedCloneTest, ChildTidSharedVm) {
   TidArgs args;
   args.parent_tid = LIBC_NAMESPACE::gettid();
   void *stack_top = get_child_stack_top();
-  pid_t pid = LIBC_NAMESPACE::clone(
-      check_tid_child, stack_top, CLONE_VM | CLONE_VFORK | SIGCHLD, &args);
+  pid_t pid = LIBC_NAMESPACE::clone(check_tid_child, stack_top,
+                                    CLONE_VM | CLONE_VFORK | SIGCHLD, &args);
   ASSERT_ERRNO_SUCCESS();
   ASSERT_GT(pid, 0);
 

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https://github.com/llvm/llvm-project/pull/224257