Reland "[libc][NFC] adjust time related implementations"" (#91687)

Reverts llvm/llvm-project#91657 and Relands #91485

27 files changed, 331 insertions, 75 deletions

diff --git a/libc/hdr/CMakeLists.txt b/libc/hdr/CMakeLists.txt
index 179b05e6ee96..754934251430 100644
--- a/libc/hdr/CMakeLists.txt
+++ b/libc/hdr/CMakeLists.txt
@@ -68,4 +68,13 @@ add_proxy_header_library(
     libc.include.llvm-libc-macros.sys_epoll_macros
 )
 
+add_proxy_header_library(
+  time_macros
+  HDRS
+    time_macros.h
+  FULL_BUILD_DEPENDS
+    libc.include.time
+    libc.include.llvm-libc-macros.time_macros
+)
+
 add_subdirectory(types)
diff --git a/libc/hdr/time_macros.h b/libc/hdr/time_macros.h
new file mode 100644
index 000000000000..dc36fe66f7a8
--- /dev/null
+++ b/libc/hdr/time_macros.h
@@ -0,0 +1,22 @@
+//===-- Definition of macros from time.h ----------------------------------===//
+//
+// 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_HDR_TIME_MACROS_H
+#define LLVM_LIBC_HDR_TIME_MACROS_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-macros/time-macros.h"
+
+#else // Overlay mode
+
+#include <time.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TIME_MACROS_H
diff --git a/libc/hdr/types/CMakeLists.txt b/libc/hdr/types/CMakeLists.txt
index 46a66ec59020..3a1bb2f3c340 100644
--- a/libc/hdr/types/CMakeLists.txt
+++ b/libc/hdr/types/CMakeLists.txt
@@ -63,3 +63,48 @@ add_proxy_header_library(
     libc.include.llvm-libc-types.fexcept_t
     libc.include.fenv
 )
+
+add_proxy_header_library(
+  time_t
+  HDRS
+    time_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.time_t
+    libc.include.time
+)
+
+add_proxy_header_library(
+  clockid_t
+  HDRS
+    clockid_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.clockid_t
+    libc.include.sys_types
+)
+
+add_proxy_header_library(
+  clock_t
+  HDRS
+    clock_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.clock_t
+    libc.include.time
+)
+
+add_proxy_header_library(
+  suseconds_t
+  HDRS
+    suseconds_t.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.suseconds_t
+    libc.include.sys_time
+)
+
+add_proxy_header_library(
+  struct_timeval
+  HDRS
+    struct_timeval.h
+  FULL_BUILD_DEPENDS
+    libc.include.llvm-libc-types.struct_timeval
+    libc.include.sys_time
+)
diff --git a/libc/hdr/types/clock_t.h b/libc/hdr/types/clock_t.h
new file mode 100644
index 000000000000..b0b658e96c3d
--- /dev/null
+++ b/libc/hdr/types/clock_t.h
@@ -0,0 +1,22 @@
+//===-- Proxy for clock_t -------------------------------------------------===//
+//
+// 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_HDR_TYPES_CLOCK_T_H
+#define LLVM_LIBC_HDR_TYPES_CLOCK_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/clock_t.h"
+
+#else // Overlay mode
+
+#include <sys/types.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_CLOCK_T_H
diff --git a/libc/hdr/types/clockid_t.h b/libc/hdr/types/clockid_t.h
new file mode 100644
index 000000000000..333342072a2f
--- /dev/null
+++ b/libc/hdr/types/clockid_t.h
@@ -0,0 +1,22 @@
+//===-- Proxy for clockid_t -----------------------------------------------===//
+//
+// 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_HDR_TYPES_CLOCKID_T_H
+#define LLVM_LIBC_HDR_TYPES_CLOCKID_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/clockid_t.h"
+
+#else // Overlay mode
+
+#include <sys/types.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_CLOCKID_T_H
diff --git a/libc/hdr/types/struct_timeval.h b/libc/hdr/types/struct_timeval.h
new file mode 100644
index 000000000000..8fc321a52d71
--- /dev/null
+++ b/libc/hdr/types/struct_timeval.h
@@ -0,0 +1,21 @@
+//===-- Proxy for struct timeval  ----------------------------------------===//
+//
+// 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_HDR_TYPES_STRUCT_TIMEVAL_H
+#define LLVM_LIBC_HDR_TYPES_STRUCT_TIMEVAL_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/struct_timeval.h"
+
+#else
+
+#include <sys/time.h>
+
+#endif // LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_STRUCT_TIMEVAL_H
diff --git a/libc/hdr/types/suseconds_t.h b/libc/hdr/types/suseconds_t.h
new file mode 100644
index 000000000000..72e54a965f75
--- /dev/null
+++ b/libc/hdr/types/suseconds_t.h
@@ -0,0 +1,22 @@
+//===-- Proxy for suseconds_t ---------------------------------------------===//
+//
+// 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_HDR_TIMES_SUSECONDS_T_H
+#define LLVM_LIBC_HDR_TIMES_SUSECONDS_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/suseconds_t.h"
+
+#else // Overlay mode
+
+#include <sys/types.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // #ifndef LLVM_LIBC_HDR_TIMES_SUSECONDS_T_H
diff --git a/libc/hdr/types/time_t.h b/libc/hdr/types/time_t.h
new file mode 100644
index 000000000000..fc9a1506a2cd
--- /dev/null
+++ b/libc/hdr/types/time_t.h
@@ -0,0 +1,22 @@
+//===-- Proxy for time_t --------------------------------------------------===//
+//
+// 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_HDR_TYPES_TIME_T_H
+#define LLVM_LIBC_HDR_TYPES_TIME_T_H
+
+#ifdef LIBC_FULL_BUILD
+
+#include "include/llvm-libc-types/time_t.h"
+
+#else // Overlay mode
+
+#include <time.h>
+
+#endif // LLVM_LIBC_FULL_BUILD
+
+#endif // LLVM_LIBC_HDR_TYPES_TIME_T_H
diff --git a/libc/src/__support/CMakeLists.txt b/libc/src/__support/CMakeLists.txt
index dcae55e050bf..32d693ec6a26 100644
--- a/libc/src/__support/CMakeLists.txt
+++ b/libc/src/__support/CMakeLists.txt
@@ -281,3 +281,5 @@ add_subdirectory(File)
 add_subdirectory(HashTable)
 
 add_subdirectory(fixed_point)
+
+add_subdirectory(time)
diff --git a/libc/src/__support/time/CMakeLists.txt b/libc/src/__support/time/CMakeLists.txt
new file mode 100644
index 000000000000..89ddffb09938
--- /dev/null
+++ b/libc/src/__support/time/CMakeLists.txt
@@ -0,0 +1,12 @@
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/${LIBC_TARGET_OS})
+  add_subdirectory(${LIBC_TARGET_OS})
+endif()
+
+add_header_library(
+  units
+  HDRS
+    units.h
+  DEPENDS
+    libc.src.__support.common
+    libc.hdr.types.time_t
+)
diff --git a/libc/src/__support/time/linux/CMakeLists.txt b/libc/src/__support/time/linux/CMakeLists.txt
new file mode 100644
index 000000000000..f04d550555e1
--- /dev/null
+++ b/libc/src/__support/time/linux/CMakeLists.txt
@@ -0,0 +1,14 @@
+add_object_library(
+  clock_gettime
+  HDRS
+    clock_gettime.h
+  SRCS
+    clock_gettime.cpp
+  DEPENDS
+    libc.include.sys_syscall
+    libc.hdr.types.struct_timespec
+    libc.hdr.types.clockid_t
+    libc.src.__support.common
+    libc.src.__support.error_or
+    libc.src.__support.OSUtil.osutil
+)
diff --git a/libc/src/time/linux/clockGetTimeImpl.h b/libc/src/__support/time/linux/clock_gettime.cpp
index 8c8c9fcf845c..7f266b282a39 100644
--- a/libc/src/time/linux/clockGetTimeImpl.h
+++ b/libc/src/__support/time/linux/clock_gettime.cpp
@@ -1,4 +1,4 @@
-//===- Linux implementation of the POSIX clock_gettime function -*- C++ -*-===//
+//===--- 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.
@@ -6,23 +6,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLVM_LIBC_SRC_TIME_LINUX_CLOCKGETTIMEIMPL_H
-#define LLVM_LIBC_SRC_TIME_LINUX_CLOCKGETTIMEIMPL_H
-
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
-#include "src/__support/common.h"
-#include "src/__support/error_or.h"
-#include "src/errno/libc_errno.h"
-
-#include <stdint.h>      // For int64_t.
-#include <sys/syscall.h> // For syscall numbers.
-#include <time.h>
-
+#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/OSUtil/syscall.h"
+#include <sys/syscall.h>
 namespace LIBC_NAMESPACE {
 namespace internal {
-
-LIBC_INLINE ErrorOr<int> clock_gettimeimpl(clockid_t clockid,
-                                           struct timespec *ts) {
+ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts) {
 #if SYS_clock_gettime
   int ret = LIBC_NAMESPACE::syscall_impl<int>(SYS_clock_gettime,
                                               static_cast<long>(clockid),
@@ -44,5 +33,3 @@ LIBC_INLINE ErrorOr<int> clock_gettimeimpl(clockid_t clockid,
 
 } // namespace internal
 } // namespace LIBC_NAMESPACE
-
-#endif // LLVM_LIBC_SRC_TIME_LINUX_CLOCKGETTIMEIMPL_H
diff --git a/libc/src/__support/time/linux/clock_gettime.h b/libc/src/__support/time/linux/clock_gettime.h
new file mode 100644
index 000000000000..b1572726f630
--- /dev/null
+++ b/libc/src/__support/time/linux/clock_gettime.h
@@ -0,0 +1,23 @@
+//===--- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_GETTIME_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_GETTIME_H
+#include "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/common.h"
+
+#include "src/__support/error_or.h"
+
+namespace LIBC_NAMESPACE {
+namespace internal {
+ErrorOr<int> clock_gettime(clockid_t clockid, timespec *ts);
+}
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_LINUX_CLOCK_GETTIME_H
diff --git a/libc/src/__support/time/units.h b/libc/src/__support/time/units.h
new file mode 100644
index 000000000000..f6bd19f9b139
--- /dev/null
+++ b/libc/src/__support/time/units.h
@@ -0,0 +1,38 @@
+//===--- Time units conversion ----------------------------------*- 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___SUPPORT_TIME_UNITS_H
+#define LLVM_LIBC_SRC___SUPPORT_TIME_UNITS_H
+
+#include "hdr/types/time_t.h"
+#include "src/__support/common.h"
+
+namespace LIBC_NAMESPACE {
+namespace time_units {
+LIBC_INLINE constexpr time_t operator""_s_ns(unsigned long long s) {
+  return s * 1'000'000'000;
+}
+LIBC_INLINE constexpr time_t operator""_s_us(unsigned long long s) {
+  return s * 1'000'000;
+}
+LIBC_INLINE constexpr time_t operator""_s_ms(unsigned long long s) {
+  return s * 1'000;
+}
+LIBC_INLINE constexpr time_t operator""_ms_ns(unsigned long long ms) {
+  return ms * 1'000'000;
+}
+LIBC_INLINE constexpr time_t operator""_ms_us(unsigned long long ms) {
+  return ms * 1'000;
+}
+LIBC_INLINE constexpr time_t operator""_us_ns(unsigned long long us) {
+  return us * 1'000;
+}
+} // namespace time_units
+} // namespace LIBC_NAMESPACE
+
+#endif // LLVM_LIBC_SRC___SUPPORT_TIME_UNITS_H
diff --git a/libc/src/time/clock.h b/libc/src/time/clock.h
index d4af7656644a..f5d14d036e13 100644
--- a/libc/src/time/clock.h
+++ b/libc/src/time/clock.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_TIME_CLOCK_H
 #define LLVM_LIBC_SRC_TIME_CLOCK_H
 
-#include <time.h>
+#include "hdr/types/clock_t.h"
 
 namespace LIBC_NAMESPACE {
 
diff --git a/libc/src/time/clock_gettime.h b/libc/src/time/clock_gettime.h
index 72e2e1949feb..48e81a355429 100644
--- a/libc/src/time/clock_gettime.h
+++ b/libc/src/time/clock_gettime.h
@@ -9,11 +9,12 @@
 #ifndef LLVM_LIBC_SRC_TIME_CLOCK_GETTIME_H
 #define LLVM_LIBC_SRC_TIME_CLOCK_GETTIME_H
 
-#include <time.h>
+#include "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
 
 namespace LIBC_NAMESPACE {
 
-int clock_gettime(clockid_t clockid, struct timespec *tp);
+int clock_gettime(clockid_t clockid, timespec *tp);
 
 } // namespace LIBC_NAMESPACE
 
diff --git a/libc/src/time/gettimeofday.h b/libc/src/time/gettimeofday.h
index 880b94cee731..62ee31edcad6 100644
--- a/libc/src/time/gettimeofday.h
+++ b/libc/src/time/gettimeofday.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_TIME_GETTIMEOFDAY_H
 #define LLVM_LIBC_SRC_TIME_GETTIMEOFDAY_H
 
-#include <time.h>
+#include "hdr/types/struct_timeval.h"
 
 namespace LIBC_NAMESPACE {
 
diff --git a/libc/src/time/gpu/CMakeLists.txt b/libc/src/time/gpu/CMakeLists.txt
index bb79d92399b3..088271d88191 100644
--- a/libc/src/time/gpu/CMakeLists.txt
+++ b/libc/src/time/gpu/CMakeLists.txt
@@ -4,6 +4,9 @@ add_object_library(
     time_utils.cpp
   HDRS
     time_utils.h
+  DEPENDS
+    libc.hdr.types.clock_t
+    libc.hdr.time_macros
 )
 
 add_entrypoint_object(
diff --git a/libc/src/time/gpu/clock.cpp b/libc/src/time/gpu/clock.cpp
index 86cc97e2a3bf..8ddfc27975bb 100644
--- a/libc/src/time/gpu/clock.cpp
+++ b/libc/src/time/gpu/clock.cpp
@@ -6,9 +6,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "time_utils.h"
-
 #include "src/time/clock.h"
+#include "src/time/gpu/time_utils.h"
 
 namespace LIBC_NAMESPACE {
 
diff --git a/libc/src/time/gpu/time_utils.h b/libc/src/time/gpu/time_utils.h
index 8a9a5f0f65b8..3f1fd11c1791 100644
--- a/libc/src/time/gpu/time_utils.h
+++ b/libc/src/time/gpu/time_utils.h
@@ -9,8 +9,9 @@
 #ifndef LLVM_LIBC_SRC_TIME_GPU_TIME_UTILS_H
 #define LLVM_LIBC_SRC_TIME_GPU_TIME_UTILS_H
 
+#include "hdr/time_macros.h"
+#include "hdr/types/clock_t.h"
 #include "src/__support/GPU/utils.h"
-
 namespace LIBC_NAMESPACE {
 
 #if defined(LIBC_TARGET_ARCH_IS_AMDGPU)
diff --git a/libc/src/time/linux/CMakeLists.txt b/libc/src/time/linux/CMakeLists.txt
index df79bf598626..c15fb44ad5d1 100644
--- a/libc/src/time/linux/CMakeLists.txt
+++ b/libc/src/time/linux/CMakeLists.txt
@@ -5,9 +5,9 @@ add_entrypoint_object(
   HDRS
     ../time_func.h
   DEPENDS
-    libc.include.time
-    libc.include.sys_syscall
-    libc.src.__support.OSUtil.osutil
+    libc.hdr.time_macros
+    libc.hdr.types.time_t
+    libc.src.__support.time.linux.clock_gettime
     libc.src.errno.errno
 )
 
@@ -18,10 +18,11 @@ add_entrypoint_object(
   HDRS
     ../clock.h
   DEPENDS
-    libc.include.time
-    libc.include.sys_syscall
+    libc.hdr.time_macros
+    libc.hdr.types.clock_t
+    libc.src.__support.time.units
+    libc.src.__support.time.linux.clock_gettime
     libc.src.__support.CPP.limits
-    libc.src.__support.OSUtil.osutil
     libc.src.errno.errno
 )
 
@@ -32,10 +33,10 @@ add_entrypoint_object(
   HDRS
     ../nanosleep.h
   DEPENDS
-    libc.include.time
+    libc.hdr.types.struct_timespec
     libc.include.sys_syscall
-    libc.src.__support.CPP.limits
     libc.src.__support.OSUtil.osutil
+    libc.src.__support.CPP.limits
     libc.src.errno.errno
 )
 
@@ -46,9 +47,9 @@ add_entrypoint_object(
   HDRS
     ../clock_gettime.h
   DEPENDS
-    libc.include.time
-    libc.include.sys_syscall
-    libc.src.__support.OSUtil.osutil
+    libc.hdr.types.clockid_t
+    libc.hdr.types.struct_timespec
+    libc.src.__support.time.linux.clock_gettime
     libc.src.errno.errno
 )
 
@@ -59,8 +60,9 @@ add_entrypoint_object(
   HDRS
     ../gettimeofday.h
   DEPENDS
-    libc.include.time
-    libc.include.sys_syscall
-    libc.src.__support.OSUtil.osutil
+    libc.hdr.time_macros
+    libc.hdr.types.suseconds_t
+    libc.src.__support.time.linux.clock_gettime
+    libc.src.__support.time.units
     libc.src.errno.errno
 )
diff --git a/libc/src/time/linux/clock.cpp b/libc/src/time/linux/clock.cpp
index 1e95f0526bc9..2c1eee8e5d60 100644
--- a/libc/src/time/linux/clock.cpp
+++ b/libc/src/time/linux/clock.cpp
@@ -7,21 +7,19 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/time/clock.h"
-
+#include "hdr/time_macros.h"
 #include "src/__support/CPP/limits.h"
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
+#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/units.h"
 #include "src/errno/libc_errno.h"
-#include "src/time/linux/clockGetTimeImpl.h"
-
-#include <sys/syscall.h> // For syscall numbers.
-#include <time.h>
 
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(clock_t, clock, ()) {
+  using namespace time_units;
   struct timespec ts;
-  auto result = internal::clock_gettimeimpl(CLOCK_PROCESS_CPUTIME_ID, &ts);
+  auto result = internal::clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
   if (!result.has_value()) {
     libc_errno = result.error();
     return -1;
@@ -34,15 +32,15 @@ LLVM_LIBC_FUNCTION(clock_t, clock, ()) {
       cpp::numeric_limits<clock_t>::max() / CLOCKS_PER_SEC;
   if (ts.tv_sec > CLOCK_SECS_MAX)
     return clock_t(-1);
-  if (ts.tv_nsec / 1000000000 > CLOCK_SECS_MAX - ts.tv_sec)
+  if (ts.tv_nsec / 1_s_ns > CLOCK_SECS_MAX - ts.tv_sec)
     return clock_t(-1);
 
   // For the integer computation converting tv_nsec to clocks to work
   // correctly, we want CLOCKS_PER_SEC to be less than 1000000000.
-  static_assert(1000000000 > CLOCKS_PER_SEC,
-                "Expected CLOCKS_PER_SEC to be less than 1000000000.");
+  static_assert(1_s_ns > CLOCKS_PER_SEC,
+                "Expected CLOCKS_PER_SEC to be less than 1'000'000'000.");
   return clock_t(ts.tv_sec * CLOCKS_PER_SEC +
-                 ts.tv_nsec / (1000000000 / CLOCKS_PER_SEC));
+                 ts.tv_nsec / (1_s_ns / CLOCKS_PER_SEC));
 }
 
 } // namespace LIBC_NAMESPACE
diff --git a/libc/src/time/linux/clock_gettime.cpp b/libc/src/time/linux/clock_gettime.cpp
index 47e974a866c8..d7b8cfd245bc 100644
--- a/libc/src/time/linux/clock_gettime.cpp
+++ b/libc/src/time/linux/clock_gettime.cpp
@@ -7,21 +7,16 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/time/clock_gettime.h"
-
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
+#include "src/__support/time/linux/clock_gettime.h"
 #include "src/errno/libc_errno.h"
-#include "src/time/linux/clockGetTimeImpl.h"
-
-#include <sys/syscall.h> // For syscall numbers.
-#include <time.h>
 
 namespace LIBC_NAMESPACE {
 
 // TODO(michaelrj): Move this into time/linux with the other syscalls.
 LLVM_LIBC_FUNCTION(int, clock_gettime,
                    (clockid_t clockid, struct timespec *ts)) {
-  auto result = internal::clock_gettimeimpl(clockid, ts);
+  auto result = internal::clock_gettime(clockid, ts);
 
   // A negative return value indicates an error with the magnitude of the
   // value being the error code.
diff --git a/libc/src/time/linux/gettimeofday.cpp b/libc/src/time/linux/gettimeofday.cpp
index 07ab4d579176..f868f5ff4d4b 100644
--- a/libc/src/time/linux/gettimeofday.cpp
+++ b/libc/src/time/linux/gettimeofday.cpp
@@ -7,24 +7,24 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/time/gettimeofday.h"
-
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "hdr/time_macros.h"
+#include "hdr/types/suseconds_t.h"
 #include "src/__support/common.h"
+#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/units.h"
 #include "src/errno/libc_errno.h"
-#include "src/time/linux/clockGetTimeImpl.h"
-
-#include <sys/syscall.h> // For syscall numbers.
 
 namespace LIBC_NAMESPACE {
 
 // TODO(michaelrj): Move this into time/linux with the other syscalls.
 LLVM_LIBC_FUNCTION(int, gettimeofday,
                    (struct timeval * tv, [[maybe_unused]] void *unused)) {
+  using namespace time_units;
   if (tv == nullptr)
     return 0;
 
   struct timespec ts;
-  auto result = internal::clock_gettimeimpl(CLOCK_REALTIME, &ts);
+  auto result = internal::clock_gettime(CLOCK_REALTIME, &ts);
 
   // A negative return value indicates an error with the magnitude of the
   // value being the error code.
@@ -34,7 +34,7 @@ LLVM_LIBC_FUNCTION(int, gettimeofday,
   }
 
   tv->tv_sec = ts.tv_sec;
-  tv->tv_usec = static_cast<suseconds_t>(ts.tv_nsec / 1000);
+  tv->tv_usec = static_cast<suseconds_t>(ts.tv_nsec / 1_us_ns);
   return 0;
 }
 
diff --git a/libc/src/time/linux/time.cpp b/libc/src/time/linux/time.cpp
index e286fae095b2..32f531efb6d1 100644
--- a/libc/src/time/linux/time.cpp
+++ b/libc/src/time/linux/time.cpp
@@ -6,22 +6,18 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "src/time/time_func.h"
-
-#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "hdr/time_macros.h"
 #include "src/__support/common.h"
+#include "src/__support/time/linux/clock_gettime.h"
 #include "src/errno/libc_errno.h"
-#include "src/time/linux/clockGetTimeImpl.h"
-
-#include <sys/syscall.h> // For syscall numbers.
-#include <time.h>
+#include "src/time/time_func.h"
 
 namespace LIBC_NAMESPACE {
 
 LLVM_LIBC_FUNCTION(time_t, time, (time_t * tp)) {
   // TODO: Use the Linux VDSO to fetch the time and avoid the syscall.
   struct timespec ts;
-  auto result = internal::clock_gettimeimpl(CLOCK_REALTIME, &ts);
+  auto result = internal::clock_gettime(CLOCK_REALTIME, &ts);
   if (!result.has_value()) {
     libc_errno = result.error();
     return -1;
diff --git a/libc/src/time/nanosleep.h b/libc/src/time/nanosleep.h
index 757394232c07..2309666b2304 100644
--- a/libc/src/time/nanosleep.h
+++ b/libc/src/time/nanosleep.h
@@ -9,11 +9,11 @@
 #ifndef LLVM_LIBC_SRC_TIME_NANOSLEEP_H
 #define LLVM_LIBC_SRC_TIME_NANOSLEEP_H
 
-#include <time.h>
+#include "hdr/types/struct_timespec.h"
 
 namespace LIBC_NAMESPACE {
 
-int nanosleep(const struct timespec *req, struct timespec *rem);
+int nanosleep(const timespec *req, timespec *rem);
 
 } // namespace LIBC_NAMESPACE
 
diff --git a/libc/src/time/time_func.h b/libc/src/time/time_func.h
index beb02020b575..2a5239220942 100644
--- a/libc/src/time/time_func.h
+++ b/libc/src/time/time_func.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_TIME_TIME_FUNC_H
 #define LLVM_LIBC_SRC_TIME_TIME_FUNC_H
 
-#include <time.h>
+#include "hdr/types/time_t.h"
 
 // Note this header file is named time_func.h to avoid conflicts with the
 // public header file time.h.