[libc] cleanup changes to gettimeofday.

[rtenneti]

Summary

+ Deleted duplicate definitions of StructTimeVal and StructTimeValPtr.
+ Caled syscall clock_gettime to get timespec data.
+ Added tests to test for sleeping 200 and 1000 microseconds.
+ Fixed comments from https://reviews.llvm.org/D137881

[sivachandra]

libc/src/time/gettimeofday.cpp

26

Nit: You can avoid the clockid var and just use long(CLOCK_REALTIME) here.

libc/spec/posix.td

 def StructDirent : NamedType<"struct dirent">;
 def StructDirentPtr : PtrType<StructDirent>;
 def StructDirentPtrPtr : PtrType<StructDirentPtr>;
 def ConstStructDirentPtrPtr : ConstType<StructDirentPtrPtr>;
 
 def StructTimeSpec : NamedType<"struct timespec">;
 def StructTimeSpecPtr : PtrType<StructTimeSpec>;
 
-def StructTimeVal : NamedType<"struct timeval">;
-def StructTimeValPtr : PtrType<StructTimeVal>;
-
 def ExecArgvT : NamedType<"__exec_argv_t">;
 def ExecEnvpT : NamedType<"__exec_envp_t">;
 
 def AtForkCallbackT : NamedType<"__atfork_callback_t">;
 
 def PosixSpawnFileActionsT : NamedType<"posix_spawn_file_actions_t">;
 def PosixSpawnFileActionsTPtr : PtrType<PosixSpawnFileActionsT>;
 def ConstPosixSpawnFileActionsTPtr : ConstType<PosixSpawnFileActionsTPtr>;
HeaderSpec SysStat = HeaderSpec<
     [], // Macros
     [
         ModeTType,
         DevT,
         InoT,
         UidT,
         GidT,
         StructTimeSpec,
-        StructTimeVal,
+        StructTimevalType,
         BlkSizeT,
         BlkCntT,
         OffTType,
         NLinkT,
         StatType,
     ], // Types
     [], // Enumerations
     [
HeaderSpec Dirent = HeaderSpec<
               [ArgSpec<DIRPtr>]
           >,
       ]
   >;
 
   HeaderSpec Time = HeaderSpec<
       "time.h",
       [], // Macros
-      [ClockIdT, StructTimeSpec, StructTimeVal], // Types
+      [ClockIdT, StructTimeSpec, StructTimevalType], // Types
       [], // Enumerations
       [
           FunctionSpec<
               "clock_gettime",
               RetValSpec<IntType>,
               [ArgSpec<ClockIdT>, ArgSpec<StructTimeSpecPtr>]
           >,
           FunctionSpec<
               "gettimeofday",
               RetValSpec<IntType>,
-              [ArgSpec<StructTimeValPtr>, ArgSpec<VoidPtr>]
+              [ArgSpec<StructTimevalPtr>, ArgSpec<VoidPtr>]
           >,
           FunctionSpec<
               "nanosleep",
               RetValSpec<IntType>,
               [ArgSpec<StructTimeSpecPtr>, ArgSpec<StructTimeSpecPtr>]
           >,
       ]
   >;

libc/src/time/gettimeofday.cpp

 //===-- Implementation of gettimeofday 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/gettimeofday.h"
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
-#include "src/time/clock_gettime.h"
 
 #include <errno.h>
 #include <sys/syscall.h> // For syscall numbers.
 
 namespace __llvm_libc {
 
 LLVM_LIBC_FUNCTION(int, gettimeofday,
                    (struct timeval * tv, [[maybe_unused]] void *unused)) {
   if (tv == nullptr)
     return 0;
   clockid_t clockid = CLOCK_REALTIME;
   struct timespec tp;
-  long ret_val = __llvm_libc::clock_gettime(clockid, &tp);
-  if (ret_val < 0)
+  long ret_val =
+      __llvm_libc::syscall_impl(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;
+  }
   tv->tv_sec = tp.tv_sec;
   tv->tv_usec = tp.tv_nsec / 1000;
   return 0;
 }
 
 } // namespace __llvm_libc

libc/test/src/time/gettimeofday_test.cpp

 #include "utils/UnitTest/Test.h"
 
 namespace cpp = __llvm_libc::cpp;
 
 TEST(LlvmLibcGettimeofday, SmokeTest) {
   using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
   void *tz = nullptr;
   struct timeval tv;
+
+  int sleep_times[2] = {200, 1000};
+  for (int i = 0; i < 2; i++) {
     int ret = __llvm_libc::gettimeofday(&tv, tz);
     ASSERT_EQ(ret, 0);
 
-  // Sleep for 200 microsceconds.
-  struct timespec tim = {0, 200 * 1000};
+    int sleep_time = -sleep_times[i];
+    // Sleep for {sleep_time} microsceconds.
+    struct timespec tim = {0, sleep_time * 1000};
     struct timespec tim2 = {0, 0};
     ret = __llvm_libc::nanosleep(&tim, &tim2);
 
-  // Call gettimeofday again and verify that it is more 100 microscecods and
-  // less than 300 microseconds,
+    // Call gettimeofday again and verify that it is more {sleep_time}
+    // microscecods.
     struct timeval tv1;
     ret = __llvm_libc::gettimeofday(&tv1, tz);
     ASSERT_EQ(ret, 0);
-  ASSERT_GT(tv1.tv_usec - tv.tv_usec, 100);
-  ASSERT_LT(tv1.tv_usec - tv.tv_usec, 300);
+    ASSERT_GE(tv1.tv_usec - tv.tv_usec, sleep_time);
+  }
 }