[libc] fix clock_gettime symbols being undefined (#117224)

`clock_gettime` being a header library discards the dependency chain
behind it.

Author: SchrodingerZhu

libc/src/__support/time/linux/CMakeLists.txt

@@ -1,7 +1,9 @@
-add_header_library(
+add_object_library(
   clock_gettime
   HDRS
     clock_gettime.h
+  SRCS
+    clock_gettime.cpp
   DEPENDS
     libc.include.sys_syscall
     libc.hdr.types.struct_timespec

libc/src/__support/time/linux/clock_gettime.cpp

@@ -0,0 +1,62 @@
+//===--- 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 "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/OSUtil/linux/vdso.h"
+#include "src/__support/OSUtil/syscall.h"
+#include "src/__support/common.h"
+#include "src/__support/error_or.h"
+#include "src/__support/macros/config.h"
+#include <sys/syscall.h>
+
+#if defined(SYS_clock_gettime64)
+#include <linux/time_types.h>
+#endif
+
+namespace LIBC_NAMESPACE_DECL {
+namespace internal {
+ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts) {
+  using namespace vdso;
+  int ret;
+#if defined(SYS_clock_gettime)
+  TypedSymbol<VDSOSym::ClockGetTime> clock_gettime;
+  if (LIBC_LIKELY(clock_gettime != nullptr))
+    ret = clock_gettime(clockid, ts);
+  else
+    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.");
+
+  TypedSymbol<VDSOSym::ClockGetTime64> clock_gettime64;
+  __kernel_timespec ts64{};
+  if (LIBC_LIKELY(clock_gettime64 != nullptr))
+    ret = clock_gettime64(clockid, &ts64);
+  else
+    ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime64,
+                                            static_cast<long>(clockid),
+                                            reinterpret_cast<long>(&ts64));
+  if (ret == 0) {
+    ts->tv_sec = static_cast<decltype(ts->tv_sec)>(ts64.tv_sec);
+    ts->tv_nsec = static_cast<decltype(ts->tv_nsec)>(ts64.tv_nsec);
+  }
+#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_DECL

libc/src/__support/time/linux/clock_gettime.h

@@ -11,55 +11,15 @@
 
 #include "hdr/types/clockid_t.h"
 #include "hdr/types/struct_timespec.h"
-#include "src/__support/OSUtil/linux/vdso.h"
-#include "src/__support/OSUtil/syscall.h"
-#include "src/__support/common.h"
 #include "src/__support/error_or.h"
-#include "src/__support/macros/config.h"
-#include <sys/syscall.h>
 
 #if defined(SYS_clock_gettime64)
 #include <linux/time_types.h>
 #endif
 
 namespace LIBC_NAMESPACE_DECL {
 namespace internal {
-LIBC_INLINE ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts) {
-  using namespace vdso;
-  int ret;
-#if defined(SYS_clock_gettime)
-  TypedSymbol<VDSOSym::ClockGetTime> clock_gettime;
-  if (LIBC_LIKELY(clock_gettime != nullptr))
-    ret = clock_gettime(clockid, ts);
-  else
-    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.");
-
-  TypedSymbol<VDSOSym::ClockGetTime64> clock_gettime64;
-  __kernel_timespec ts64{};
-  if (LIBC_LIKELY(clock_gettime64 != nullptr))
-    ret = clock_gettime64(clockid, &ts64);
-  else
-    ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime64,
-                                            static_cast<long>(clockid),
-                                            reinterpret_cast<long>(&ts64));
-  if (ret == 0) {
-    ts->tv_sec = static_cast<decltype(ts->tv_sec)>(ts64.tv_sec);
-    ts->tv_nsec = static_cast<decltype(ts->tv_nsec)>(ts64.tv_nsec);
-  }
-#else
-#error "SYS_clock_gettime and SYS_clock_gettime64 syscalls not available."
-#endif
-  if (ret < 0)
-    return Error(-ret);
-  return ret;
-}
-
+ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts);
 } // namespace internal
 } // namespace LIBC_NAMESPACE_DECL