[libc] add clock_gettime

[michaelrj]

Summary

Add the clock_gettime syscall wrapper and tests.

[sivachandra]

libc/include/llvm-libc-types/time_t.h

14 ↗

(On Diff #463354)

A new type should be defined in its own header file - we follow the rule of exactly one type defined in a complete header file. By complete header file, we mean that including it will pull dependent macros and types as well and make the type definition complete (the type itself can be of an incomplete type, for example FILE.)

[michaelrj]

move clockid_t into separate header

[sivachandra]

libc/src/time/clock_gettime.cpp

27

What is this for?

[michaelrj]

libc/src/time/clock_gettime.cpp

27

testing, I forgot to delete it.

libc/config/linux/api.td

let Types = [
     "size_t",
     "__bsearchcompare_t",
     "__qsortcompare_t",
     "__atexithandler_t",
   ];
 }
 
 def TimeAPI : PublicAPI<"time.h"> {
-  let Types = ["time_t", "struct tm", "struct timespec"];
+  let Types = ["time_t", "struct tm", "struct timespec", "clockid_t",];
 }
 
 def ErrnoAPI : PublicAPI<"errno.h"> {
   let Macros = [
     ErrnoMacro,
     // We largely depend on linux/errno.h to give us the
     // various error macro definitions. However, some libc
     // implementations have chosen to provide definitions

libc/config/linux/x86_64/entrypoints.txt

list(APPEND TARGET_LIBC_ENTRYPOINTS
 
     # time.h entrypoints
     libc.src.time.asctime
     libc.src.time.asctime_r
     libc.src.time.gmtime
     libc.src.time.gmtime_r
     libc.src.time.mktime
     libc.src.time.nanosleep
+    libc.src.time.clock_gettime
   )
 endif()
 
 set(TARGET_LLVMLIBC_ENTRYPOINTS
   ${TARGET_LIBC_ENTRYPOINTS}
   ${TARGET_LIBM_ENTRYPOINTS}
 )

libc/include/CMakeLists.txt

 )
 
 add_gen_header(
   time
   DEF_FILE time.h.def
   GEN_HDR time.h
   DEPENDS
     .llvm_libc_common_h
+    .llvm-libc-macros.time_macros
     .llvm-libc-types.time_t
+    .llvm-libc-types.clockid_t
     .llvm-libc-types.struct_tm
     .llvm-libc-types.struct_timespec
 )
 
 add_gen_header(
   threads
   DEF_FILE threads.h.def
   GEN_HDR threads.h

libc/include/llvm-libc-macros/CMakeLists.txt

add_header(
   sys_resource_macros
   HDR
     sys-resource-macros.h
   DEPENDS
     .linux.sys_resource_macros
 )
 
 add_header(
+  time_macros
+  HDR
+    time-macros.h
+  DEPENDS
+    .linux.time_macros
+)
+
+add_header(
   unistd_macros
   HDR
     unistd-macros.h
   DEPENDS
     .linux.unistd_macros
 )

libc/include/llvm-libc-macros/linux/CMakeLists.txt

 
 add_header(
   sys_stat_macros
   HDR
     sys-stat-macros.h
 )
 
 add_header(
+  time_macros
+  HDR
+    time-macros.h
+)
+
+add_header(
   sys_resource_macros
   HDR
     sys-resource-macros.h
 )
 
 add_header(
   unistd_macros
   HDR
     unistd-macros.h
 )

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

+//===-- 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_MACROS_LINUX_TIME_MACROS_H
+#define __LLVM_LIBC_MACROS_LINUX_TIME_MACROS_H
+
+// clock type macros
+#define CLOCK_REALTIME 0
+#define CLOCK_MONOTONIC 1
+#define CLOCK_PROCESS_CPUTIME_ID 2
+#define CLOCK_THREAD_CPUTIME_ID 3
+#define CLOCK_MONOTONIC_RAW 4
+#define CLOCK_REALTIME_COARSE 5
+#define CLOCK_MONOTONIC_COARSE 6
+#define CLOCK_BOOTTIME 7
+#define CLOCK_REALTIME_ALARM 8
+#define CLOCK_BOOTTIME_ALARM 9
+
+#endif //__LLVM_LIBC_MACROS_LINUX_TIME_MACROS_H

libc/include/llvm-libc-macros/time-macros.h

+#ifndef __LLVM_LIBC_MACROS_TIME_MACROS_H
+#define __LLVM_LIBC_MACROS_TIME_MACROS_H
+
+#ifdef __unix__
+#include "linux/time-macros.h"
+#endif
+
+#endif // __LLVM_LIBC_MACROS_TIME_MACROS_H

libc/include/llvm-libc-types/CMakeLists.txt

 add_header(off64_t HDR off64_t.h)
 add_header(size_t HDR size_t.h)
 add_header(__bsearchcompare_t HDR __bsearchcompare_t.h)
 add_header(__call_once_func_t HDR __call_once_func_t.h)
 add_header(__futex_word HDR __futex_word.h)
 add_header(__mutex_type HDR __mutex_type.h DEPENDS .__futex_word)
 add_header(__pthread_once_func_t HDR __pthread_once_func_t.h)
 add_header(__pthread_start_t HDR __pthread_start_t.h)
 add_header(__pthread_tss_dtor_t HDR __pthread_tss_dtor_t.h)
 add_header(__qsortcompare_t HDR __qsortcompare_t.h)
 add_header(__sighandler_t HDR __sighandler_t.h)
 add_header(__thread_type HDR __thread_type.h)
 add_header(blkcnt_t HDR blkcnt_t.h)
 add_header(blksize_t HDR blksize_t.h)
+add_header(clockid_t HDR clockid_t.h)
 add_header(cnd_t HDR cnd_t.h)
 add_header(cookie_io_functions_t HDR cookie_io_functions_t.h DEPENDS .off64_t)
 add_header(double_t HDR double_t.h)
 add_header(DIR HDR DIR.h)
 add_header(dev_t HDR dev_t.h)
 add_header(div_t HDR div_t.h)
 add_header(ldiv_t HDR ldiv_t.h)
 add_header(lldiv_t HDR lldiv_t.h)

libc/include/llvm-libc-types/clockid_t.h

-//===-- C standard library header time.h ----------------------------------===//
+//===-- Definition of the type 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_TIME_H
-#define LLVM_LIBC_TIME_H
+#ifndef __LLVM_LIBC_TYPES_CLOCKID_T_H__
+#define __LLVM_LIBC_TYPES_CLOCKID_T_H__
 
-#include <__llvm-libc-common.h>
+typedef int clockid_t;
 
-%%public_api()
-
-#endif // LLVM_LIBC_TIME_H
+#endif // __LLVM_LIBC_TYPES_CLOCKID_T_H__

libc/include/time.h.def

 //===-- C standard library header 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_TIME_H
 #define LLVM_LIBC_TIME_H
 
 #include <__llvm-libc-common.h>
+#include <llvm-libc-macros/time-macros.h>
 
 %%public_api()
 
 #endif // LLVM_LIBC_TIME_H

libc/spec/posix.td

 def PThreadOnceT : NamedType<"pthread_once_t">;
 def PThreadOnceTPtr : PtrType<PThreadOnceT>;
 def PThreadOnceCallback : NamedType<"__pthread_once_func_t">;
 
 def InoT : NamedType<"ino_t">;
 def UidT : NamedType<"uid_t">;
 def GidT : NamedType<"gid_t">;
 def DevT : NamedType<"dev_t">;
+def ClockIdT : NamedType<"clockid_t">;
 def BlkSizeT : NamedType<"blksize_t">;
 def BlkCntT : NamedType<"blkcnt_t">;
 def NLinkT : NamedType<"nlink_t">;
-def TimeSpec : NamedType<"struct timespec">;
 def PidT : NamedType<"pid_t">;
 
 def StatType : NamedType<"struct stat">;
 def StatTypePtr : PtrType<StatType>;
 def RestrictedStatTypePtr : RestrictedPtrType<StatType>;
 
 def DIR : NamedType<"DIR">;
 def DIRPtr : PtrType<DIR>;
[
           [ArgSpec<ConstStructRLimitPtr>]
         >,
     ]
   >;
 
   HeaderSpec SysStat = HeaderSpec<
     "sys/stat.h",
     [], // Macros
-    [ModeTType, DevT, InoT, UidT, GidT, TimeSpec, BlkSizeT, BlkCntT, OffTType, NLinkT, StatType], // Types
+    [ModeTType, DevT, InoT, UidT, GidT, StructTimeSpec, BlkSizeT, BlkCntT, OffTType, NLinkT, StatType], // Types
     [], // Enumerations
     [
         FunctionSpec<
           "chmod",
           RetValSpec<IntType>,
           [ArgSpec<ConstCharPtr>, ArgSpec<ModeTType>]
         >,
         FunctionSpec<
HeaderSpec Dirent = HeaderSpec<
               [ArgSpec<DIRPtr>]
           >,
       ]
   >;
 
   HeaderSpec Time = HeaderSpec<
       "time.h",
       [], // Macros
-      [StructTimeSpec], // Types
+      [ClockIdT, StructTimeSpec], // Types
       [], // Enumerations
       [
           FunctionSpec<
               "nanosleep",
               RetValSpec<IntType>,
               [
                 ArgSpec<StructTimeSpecPtr>,
                 ArgSpec<StructTimeSpecPtr>,
               ]
           >,
+          FunctionSpec<
+              "clock_gettime",
+              RetValSpec<IntType>,
+              [ArgSpec<ClockIdT>,ArgSpec<StructTimeSpecPtr>]
+          >,
       ]
   >;
 
   let Headers = [
     CType,
     Dirent,
     Errno,
     FCntl,

libc/src/time/CMakeLists.txt

add_entrypoint_object(
   HDRS
     asctime_r.h
   DEPENDS
     .time_utils
     libc.include.time
 )
 
 add_entrypoint_object(
+  clock_gettime
+  SRCS
+    clock_gettime.cpp
+  HDRS
+    clock_gettime.h
+  DEPENDS
+    libc.include.time
+    libc.include.sys_syscall
+    libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
+)
+
+add_entrypoint_object(
   gmtime
   SRCS
     gmtime.cpp
   HDRS
     gmtime.h
   DEPENDS
     .time_utils
     libc.include.time

libc/src/time/clock_gettime.h

+//===-- Implementation header for clock_gettime function --------*- 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_TIME_CLOCK_GETTIME_H
+#define LLVM_LIBC_SRC_TIME_CLOCK_GETTIME_H
+
+#include <time.h>
+
+namespace __llvm_libc {
+
+int clock_gettime(clockid_t clockid, struct timespec *tp);
+
+} // namespace __llvm_libc
+
+#endif // LLVM_LIBC_SRC_TIME_CLOCK_GETTIME_H

libc/src/time/clock_gettime.cpp

+//===---------- Linux implementation of the POSIX clock_gettime function
+//--------===//
+//
+// 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/time/clock_gettime.h"
+
+#include "src/__support/OSUtil/syscall.h" // For internal syscall function.
+#include "src/__support/common.h"
+
+#include <errno.h>
+#include <sys/syscall.h> // For syscall numbers.
+#include <time.h>
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(int, clock_gettime,
+                   (clockid_t clockid, struct timespec *tp)) {
+  long ret_val =
+      __llvm_libc::syscall(SYS_clock_gettime, static_cast<long>(clockid),
+                           reinterpret_cast<long>(tp));
+  // A negative return value indicates an error with the magnitude of the
+  // value being the error code.
+  if (ret_val < 0) {
+    errno = -ret_val;
+    return -1;
+  }
+
+  return 0;
+}
+
+} // namespace __llvm_libc

libc/test/src/time/CMakeLists.txt

HDRS
     TmMatcher.h
   CXX_STANDARD
     20
   DEPENDS
     libc.src.time.asctime_r
 )
 
 add_libc_unittest(
+  clock_gettime
+  SUITE
+    libc_time_unittests
+  SRCS
+  clock_gettime_test.cpp
+  DEPENDS
+    libc.src.time.clock_gettime
+)
+
+add_libc_unittest(
   gmtime
   SUITE
     libc_time_unittests
   SRCS
     gmtime_test.cpp
   HDRS
     TmMatcher.h
   DEPENDS

libc/test/src/time/clock_gettime_test.cpp

+//===-- Unittests for clock_gettime ---------------------------------------===//
+//
+// 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/time/clock_gettime.h"
+#include "utils/UnitTest/Test.h"
+
+#include <time.h>
+
+TEST(LlvmLibcClockGetTime, RealTime) {
+  struct timespec tp;
+  int result;
+  result = clock_gettime(CLOCK_REALTIME, &tp);
+  ASSERT_EQ(result, 0);
+  ASSERT_GT(tp.tv_sec, time_t(0));
+}
+
+#ifdef CLOCK_MONOTONIC
+TEST(LlvmLibcClockGetTime, MonotonicTime) {
+  struct timespec tp1, tp2;
+  int result;
+  result = clock_gettime(CLOCK_MONOTONIC, &tp1);
+  ASSERT_EQ(result, 0);
+  ASSERT_GT(tp1.tv_sec, time_t(0));
+  result = clock_gettime(CLOCK_MONOTONIC, &tp2);
+  ASSERT_EQ(result, 0);
+  ASSERT_GE(tp2.tv_sec, tp1.tv_sec); // The monotonic clock should increase.
+  if (tp2.tv_sec == tp1.tv_sec) {
+    ASSERT_GE(tp2.tv_nsec, tp1.tv_nsec);
+  }
+}
+#endif // CLOCK_MONOTONIC