Merge branch 'main' into users/meinersbur/flang_runtime_split-headersusers/meinersbur/flang_runtime_split-headers

17 files changed, 194 insertions, 131 deletions

diff --git a/libc/src/time/CMakeLists.txt b/libc/src/time/CMakeLists.txt
index f18e74a15e6f..ae835dcc7427 100644
--- a/libc/src/time/CMakeLists.txt
+++ b/libc/src/time/CMakeLists.txt
@@ -106,9 +106,15 @@ add_entrypoint_object(
 
 add_entrypoint_object(
   time
-  ALIAS
+  SRCS
+    time.cpp
+  HDRS
+    time_func.h
   DEPENDS
-    .${LIBC_TARGET_OS}.time
+    libc.hdr.time_macros
+    libc.hdr.types.time_t
+    libc.src.__support.time.clock_gettime
+    libc.src.errno.errno
 )
 
 add_entrypoint_object(
@@ -145,3 +151,10 @@ add_entrypoint_object(
   DEPENDS
     .${LIBC_TARGET_OS}.gettimeofday
 )
+
+add_entrypoint_object(
+  clock_getres
+  ALIAS
+  DEPENDS
+    .${LIBC_TARGET_OS}.clock_getres
+)
diff --git a/libc/src/time/clock_getres.h b/libc/src/time/clock_getres.h
new file mode 100644
index 000000000000..c1c581c53599
--- /dev/null
+++ b/libc/src/time/clock_getres.h
@@ -0,0 +1,21 @@
+//===-- Implementation header of clock_getres -------------------*- 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_GETRES_H
+#define LLVM_LIBC_SRC_TIME_CLOCK_GETRES_H
+
+#include "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
+#include "src/__support/macros/config.h"
+
+namespace LIBC_NAMESPACE_DECL {
+
+int clock_getres(clockid_t clockid, timespec *tp);
+
+} // namespace LIBC_NAMESPACE_DECL
+
+#endif // LLVM_LIBC_SRC_TIME_CLOCK_GETRES_H
diff --git a/libc/src/time/gpu/CMakeLists.txt b/libc/src/time/gpu/CMakeLists.txt
index 8da5d3a22f5a..31a60595d68f 100644
--- a/libc/src/time/gpu/CMakeLists.txt
+++ b/libc/src/time/gpu/CMakeLists.txt
@@ -1,14 +1,3 @@
-add_object_library(
-  time_utils
-  SRCS
-    time_utils.cpp
-  HDRS
-    time_utils.h
-  DEPENDS
-    libc.hdr.types.clock_t
-    libc.hdr.time_macros
-)
-
 add_entrypoint_object(
   clock
   SRCS
@@ -18,7 +7,8 @@ add_entrypoint_object(
   DEPENDS
     libc.include.time
     libc.src.__support.GPU.utils
-    .time_utils
+    libc.src.__support.time.clock_gettime
+    libc.src.__support.time.gpu.time_utils
 )
 
 add_entrypoint_object(
@@ -30,29 +20,31 @@ add_entrypoint_object(
   DEPENDS
     libc.include.time
     libc.src.__support.GPU.utils
-    .time_utils
+    libc.src.__support.time.gpu.time_utils
 )
 
 add_entrypoint_object(
-  clock_gettime
+  timespec_get
   SRCS
-    clock_gettime.cpp
+    timespec_get.cpp
   HDRS
-    ../clock_gettime.h
+    ../timespec_get.h
   DEPENDS
-    libc.hdr.types.clockid_t
+    libc.hdr.time_macros
     libc.hdr.types.struct_timespec
-    .time_utils
+    libc.src.__support.time.gpu.time_utils
 )
 
 add_entrypoint_object(
-  timespec_get
+  clock_gettime
   SRCS
-    timespec_get.cpp
+    clock_gettime.cpp
   HDRS
-    ../timespec_get.h
+    ../clock_gettime.h
   DEPENDS
     libc.hdr.time_macros
+    libc.hdr.types.clockid_t
     libc.hdr.types.struct_timespec
-    .time_utils
+    libc.src.__support.time.gpu.time_utils
+    libc.src.__support.time.clock_gettime
 )
diff --git a/libc/src/time/gpu/clock.cpp b/libc/src/time/gpu/clock.cpp
index 4cdb1d505aed..add5b2725ef8 100644
--- a/libc/src/time/gpu/clock.cpp
+++ b/libc/src/time/gpu/clock.cpp
@@ -8,7 +8,7 @@
 
 #include "src/time/clock.h"
 #include "src/__support/macros/config.h"
-#include "src/time/gpu/time_utils.h"
+#include "src/__support/time/gpu/time_utils.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
diff --git a/libc/src/time/gpu/clock_gettime.cpp b/libc/src/time/gpu/clock_gettime.cpp
index de7899a2a17c..81547ef7f1ca 100644
--- a/libc/src/time/gpu/clock_gettime.cpp
+++ b/libc/src/time/gpu/clock_gettime.cpp
@@ -10,23 +10,16 @@
 
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
-#include "time_utils.h"
+#include "src/__support/time/clock_gettime.h"
+#include "src/__support/time/gpu/time_utils.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
-constexpr uint64_t TICKS_PER_SEC = 1000000000UL;
-
 LLVM_LIBC_FUNCTION(int, clock_gettime, (clockid_t clockid, timespec *ts)) {
-  if (clockid != CLOCK_MONOTONIC || !ts)
-    return -1;
-
-  uint64_t ns_per_tick = TICKS_PER_SEC / GPU_CLOCKS_PER_SEC;
-  uint64_t ticks = gpu::fixed_frequency_clock();
-
-  ts->tv_nsec = (ticks * ns_per_tick) % TICKS_PER_SEC;
-  ts->tv_sec = (ticks * ns_per_tick) / TICKS_PER_SEC;
-
-  return 0;
+  ErrorOr<int> result = internal::clock_gettime(clockid, ts);
+  if (result)
+    return result.value();
+  return result.error();
 }
 
 } // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/time/gpu/nanosleep.cpp b/libc/src/time/gpu/nanosleep.cpp
index 3f4a609dd40e..a92f660f225c 100644
--- a/libc/src/time/gpu/nanosleep.cpp
+++ b/libc/src/time/gpu/nanosleep.cpp
@@ -9,12 +9,10 @@
 #include "src/time/nanosleep.h"
 
 #include "src/__support/macros/config.h"
-#include "time_utils.h"
+#include "src/__support/time/gpu/time_utils.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
-constexpr uint64_t TICKS_PER_SEC = 1000000000UL;
-
 LLVM_LIBC_FUNCTION(int, nanosleep,
                    (const struct timespec *req, struct timespec *rem)) {
   if (!GPU_CLOCKS_PER_SEC || !req)
diff --git a/libc/src/time/gpu/time_utils.cpp b/libc/src/time/gpu/time_utils.cpp
deleted file mode 100644
index 38e09f600f36..000000000000
--- a/libc/src/time/gpu/time_utils.cpp
+++ /dev/null
@@ -1,22 +0,0 @@
-//===-- Generic utilities for GPU timing ----------------------------------===//
-//
-// 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 "time_utils.h"
-#include "src/__support/macros/config.h"
-
-namespace LIBC_NAMESPACE_DECL {
-
-#if defined(LIBC_TARGET_ARCH_IS_AMDGPU)
-// This is expected to be initialized by the runtime if the default value is
-// insufficient.
-// TODO: Once we have another use-case for this we should put it in a common
-// device environment struct.
-gpu::Constant<uint64_t> __llvm_libc_clock_freq = clock_freq;
-#endif
-
-} // namespace LIBC_NAMESPACE_DECL
diff --git a/libc/src/time/gpu/time_utils.h b/libc/src/time/gpu/time_utils.h
deleted file mode 100644
index c631a38d91ba..000000000000
--- a/libc/src/time/gpu/time_utils.h
+++ /dev/null
@@ -1,43 +0,0 @@
-//===-- Generic utilities for GPU timing ----------------------------------===//
-//
-// 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_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"
-#include "src/__support/macros/config.h"
-
-namespace LIBC_NAMESPACE_DECL {
-
-#if defined(LIBC_TARGET_ARCH_IS_AMDGPU)
-// AMDGPU does not have a single set frequency. Different architectures and
-// cards can have different values. The actualy frequency needs to be read from
-// the kernel driver and will be between 25 MHz and 100 MHz on most cards. All
-// cards following the GFX9 ISAs use a 100 MHz clock so we will default to that.
-constexpr uint64_t clock_freq = 100000000UL;
-
-// We provide an externally visible symbol such that the runtime can set
-// this to the correct value.
-extern "C" {
-[[gnu::visibility("protected")]]
-extern gpu::Constant<uint64_t> __llvm_libc_clock_freq;
-}
-#define GPU_CLOCKS_PER_SEC static_cast<clock_t>(__llvm_libc_clock_freq)
-
-#elif defined(LIBC_TARGET_ARCH_IS_NVPTX)
-// NPVTX uses a single 1 GHz fixed frequency clock for all target architectures.
-#define GPU_CLOCKS_PER_SEC static_cast<clock_t>(1000000000UL)
-#else
-#error "Unsupported target"
-#endif
-
-} // namespace LIBC_NAMESPACE_DECL
-
-#endif // LLVM_LIBC_SRC_TIME_GPU_TIME_UTILS_H
diff --git a/libc/src/time/gpu/timespec_get.cpp b/libc/src/time/gpu/timespec_get.cpp
index f4ef328a8312..0dd128444aa8 100644
--- a/libc/src/time/gpu/timespec_get.cpp
+++ b/libc/src/time/gpu/timespec_get.cpp
@@ -10,6 +10,7 @@
 #include "hdr/time_macros.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
+#include "src/__support/time/gpu/time_utils.h"
 
 namespace LIBC_NAMESPACE_DECL {
 
diff --git a/libc/src/time/linux/CMakeLists.txt b/libc/src/time/linux/CMakeLists.txt
index 31fd7d1e64c8..314623f9f425 100644
--- a/libc/src/time/linux/CMakeLists.txt
+++ b/libc/src/time/linux/CMakeLists.txt
@@ -1,17 +1,4 @@
 add_entrypoint_object(
-  time
-  SRCS
-    time.cpp
-  HDRS
-    ../time_func.h
-  DEPENDS
-    libc.hdr.time_macros
-    libc.hdr.types.time_t
-    libc.src.__support.time.linux.clock_gettime
-    libc.src.errno.errno
-)
-
-add_entrypoint_object(
   timespec_get
   SRCS
     timespec_get.cpp
@@ -20,7 +7,7 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.time_macros
     libc.hdr.types.struct_timespec
-    libc.src.__support.time.linux.clock_gettime
+    libc.src.__support.time.clock_gettime
     libc.src.errno.errno
 )
 
@@ -34,7 +21,7 @@ add_entrypoint_object(
     libc.hdr.time_macros
     libc.hdr.types.clock_t
     libc.src.__support.time.units
-    libc.src.__support.time.linux.clock_gettime
+    libc.src.__support.time.clock_gettime
     libc.src.__support.CPP.limits
     libc.src.errno.errno
 )
@@ -62,7 +49,7 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.types.clockid_t
     libc.hdr.types.struct_timespec
-    libc.src.__support.time.linux.clock_gettime
+    libc.src.__support.time.clock_gettime
     libc.src.errno.errno
 )
 
@@ -75,7 +62,7 @@ add_entrypoint_object(
   DEPENDS
     libc.hdr.time_macros
     libc.hdr.types.suseconds_t
-    libc.src.__support.time.linux.clock_gettime
+    libc.src.__support.time.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 f43e1bcad6a3..ee4fa82b4f89 100644
--- a/libc/src/time/linux/clock.cpp
+++ b/libc/src/time/linux/clock.cpp
@@ -11,7 +11,7 @@
 #include "src/__support/CPP/limits.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
-#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/clock_gettime.h"
 #include "src/__support/time/units.h"
 #include "src/errno/libc_errno.h"
 
diff --git a/libc/src/time/linux/clock_gettime.cpp b/libc/src/time/linux/clock_gettime.cpp
index a2b20a6dbc98..743c644d65d0 100644
--- a/libc/src/time/linux/clock_gettime.cpp
+++ b/libc/src/time/linux/clock_gettime.cpp
@@ -9,7 +9,7 @@
 #include "src/time/clock_gettime.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
-#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/clock_gettime.h"
 #include "src/errno/libc_errno.h"
 
 namespace LIBC_NAMESPACE_DECL {
diff --git a/libc/src/time/linux/gettimeofday.cpp b/libc/src/time/linux/gettimeofday.cpp
index 19d9988ae73a..e8ddf482fc98 100644
--- a/libc/src/time/linux/gettimeofday.cpp
+++ b/libc/src/time/linux/gettimeofday.cpp
@@ -11,7 +11,7 @@
 #include "hdr/types/suseconds_t.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
-#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/clock_gettime.h"
 #include "src/__support/time/units.h"
 #include "src/errno/libc_errno.h"
 
diff --git a/libc/src/time/linux/timespec_get.cpp b/libc/src/time/linux/timespec_get.cpp
index ba9f8eb2e442..cf5174523aa4 100644
--- a/libc/src/time/linux/timespec_get.cpp
+++ b/libc/src/time/linux/timespec_get.cpp
@@ -10,7 +10,7 @@
 #include "hdr/time_macros.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
-#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/clock_gettime.h"
 #include "src/errno/libc_errno.h"
 
 namespace LIBC_NAMESPACE_DECL {
diff --git a/libc/src/time/linux/time.cpp b/libc/src/time/time.cpp
index 20fb86e8e29d..4a0b614a68ef 100644
--- a/libc/src/time/linux/time.cpp
+++ b/libc/src/time/time.cpp
@@ -9,14 +9,14 @@
 #include "hdr/time_macros.h"
 #include "src/__support/common.h"
 #include "src/__support/macros/config.h"
-#include "src/__support/time/linux/clock_gettime.h"
+#include "src/__support/time/clock_gettime.h"
 #include "src/errno/libc_errno.h"
 #include "src/time/time_func.h"
 
 namespace LIBC_NAMESPACE_DECL {
-
-LLVM_LIBC_FUNCTION(time_t, time, (time_t * tp)) {
-  // TODO: Use the Linux VDSO to fetch the time and avoid the syscall.
+// avoid inconsitent clang-format behavior
+using time_ptr_t = time_t *;
+LLVM_LIBC_FUNCTION(time_t, time, (time_ptr_t tp)) {
   struct timespec ts;
   auto result = internal::clock_gettime(CLOCK_REALTIME, &ts);
   if (!result.has_value()) {
diff --git a/libc/src/time/windows/CMakeLists.txt b/libc/src/time/windows/CMakeLists.txt
new file mode 100644
index 000000000000..6f242cd168f5
--- /dev/null
+++ b/libc/src/time/windows/CMakeLists.txt
@@ -0,0 +1,13 @@
+add_entrypoint_object(
+    clock_getres
+    SRCS
+        clock_getres.cpp
+    DEPENDS
+        libc.src.__support.time.windows.performance_counter
+        libc.src.__support.time.units
+        libc.src.__support.common
+        libc.src.__support.macros.optimization
+        libc.hdr.time_macros
+        libc.hdr.types.time_t
+        libc.hdr.types.struct_timespec
+)
diff --git a/libc/src/time/windows/clock_getres.cpp b/libc/src/time/windows/clock_getres.cpp
new file mode 100644
index 000000000000..b8c0c82aa641
--- /dev/null
+++ b/libc/src/time/windows/clock_getres.cpp
@@ -0,0 +1,110 @@
+//===-- Windows implementation of clock_getres ------------------*- 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 "hdr/errno_macros.h"
+#include "hdr/time_macros.h"
+#include "hdr/types/clockid_t.h"
+#include "hdr/types/struct_timespec.h"
+
+#include "src/__support/CPP/limits.h"
+#include "src/__support/common.h"
+#include "src/__support/macros/optimization.h"
+#include "src/__support/time/units.h"
+#include "src/__support/time/windows/performance_counter.h"
+#include "src/errno/libc_errno.h"
+#include "src/time/clock_getres.h"
+
+#define WIN32_LEAN_AND_MEAN
+#define NOMINMAX
+#include <Windows.h>
+
+// add in dependencies for GetSystemTimeAdjustmentPrecise
+#pragma comment(lib, "mincore.lib")
+
+namespace LIBC_NAMESPACE_DECL {
+LLVM_LIBC_FUNCTION(int, clock_getres, (clockid_t id, struct timespec *res)) {
+  using namespace time_units;
+  // POSIX allows nullptr to be passed as res, in which case the function should
+  // do nothing.
+  if (res == nullptr)
+    return 0;
+  constexpr unsigned long long HNS_PER_SEC = 1_s_ns / 100ULL;
+  constexpr unsigned long long SEC_LIMIT =
+      cpp::numeric_limits<decltype(res->tv_sec)>::max();
+  // For CLOCK_MONOTONIC, we are using performance counter
+  // https://learn.microsoft.com/en-us/windows/win32/sysinfo/acquiring-high-resolution-time-stamps
+  // Hence, the resolution is given by the performance counter frequency.
+  // For CLOCK_REALTIME, the precision is given by
+  // GetSystemTimeAdjustmentPrecise
+  // (https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeadjustmentprecise)
+  // For CLOCK_PROCESS_CPUTIME_ID, CLOCK_THREAD_CPUTIME_ID, the precision is
+  // given by GetSystemTimeAdjustment
+  // (https://learn.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-getsystemtimeadjustment)
+  switch (id) {
+  default:
+    libc_errno = EINVAL;
+    return -1;
+
+  case CLOCK_MONOTONIC: {
+    long long freq = performance_counter::get_ticks_per_second();
+    __builtin_assume(freq != 0);
+    // division of 1 second by frequency, rounded up.
+    long long tv_sec = static_cast<long long>(freq == 1);
+    long long tv_nsec =
+        LIBC_LIKELY(freq != 1) ? 1ll + ((1_s_ns - 1ll) / freq) : 0ll;
+    // not possible to overflow tv_sec, tv_nsec
+    res->tv_sec = static_cast<decltype(res->tv_sec)>(tv_sec);
+    res->tv_nsec = static_cast<decltype(res->tv_nsec)>(tv_nsec);
+    break;
+  }
+
+  case CLOCK_REALTIME: {
+    [[clang::uninitialized]] DWORD64 time_adjustment;
+    [[clang::uninitialized]] DWORD64 time_increment;
+    [[clang::uninitialized]] BOOL time_adjustment_disabled;
+    if (!::GetSystemTimeAdjustmentPrecise(&time_adjustment, &time_increment,
+                                          &time_adjustment_disabled)) {
+      libc_errno = EINVAL;
+      return -1;
+    }
+    DWORD64 tv_sec = time_increment / HNS_PER_SEC;
+    DWORD64 tv_nsec = (time_increment % HNS_PER_SEC) * 100ULL;
+    if (LIBC_UNLIKELY(tv_sec > SEC_LIMIT)) {
+      libc_errno = EOVERFLOW;
+      return -1;
+    }
+    res->tv_sec = static_cast<decltype(res->tv_sec)>(tv_sec);
+    res->tv_nsec = static_cast<decltype(res->tv_nsec)>(tv_nsec);
+    break;
+  }
+  case CLOCK_PROCESS_CPUTIME_ID:
+  case CLOCK_THREAD_CPUTIME_ID: {
+    [[clang::uninitialized]] DWORD time_adjustment;
+    [[clang::uninitialized]] DWORD time_increment;
+    [[clang::uninitialized]] BOOL time_adjustment_disabled;
+    if (!::GetSystemTimeAdjustment(&time_adjustment, &time_increment,
+                                   &time_adjustment_disabled)) {
+      libc_errno = EINVAL;
+      return -1;
+    }
+    DWORD hns_per_sec = static_cast<DWORD>(HNS_PER_SEC);
+    DWORD sec_limit = static_cast<DWORD>(SEC_LIMIT);
+    DWORD tv_sec = time_increment / hns_per_sec;
+    DWORD tv_nsec = (time_increment % hns_per_sec) * 100UL;
+    if (LIBC_UNLIKELY(tv_sec > sec_limit)) {
+      libc_errno = EOVERFLOW;
+      return -1;
+    }
+    res->tv_sec = static_cast<decltype(res->tv_sec)>(tv_sec);
+    res->tv_nsec = static_cast<decltype(res->tv_nsec)>(tv_nsec);
+    break;
+  }
+  }
+  return 0;
+}
+} // namespace LIBC_NAMESPACE_DECL