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authorGravatar Abseil Team <absl-team@google.com>2022-09-26 18:43:11 -0700
committerGravatar Copybara-Service <copybara-worker@google.com>2022-09-26 18:44:06 -0700
commitdf19c209961b44299aa047d7db0d3972d94a2d0b (patch)
tree5289010d9a0f1afd914c7e0a22657acb573e1772 /absl/base
parent1cd889767e518d1bbb1bf8b226ee2c4dd3e85390 (diff)
Split configuration related to cycle clock into separate headers
PiperOrigin-RevId: 477043101 Change-Id: I009ea39ad61e7e78cdac51afc57a8ad5b4d8aa2d
Diffstat (limited to 'absl/base')
-rw-r--r--absl/base/BUILD.bazel18
-rw-r--r--absl/base/CMakeLists.txt2
-rw-r--r--absl/base/internal/cycleclock.h21
-rw-r--r--absl/base/internal/cycleclock_config.h55
-rw-r--r--absl/base/internal/unscaledcycleclock.h41
-rw-r--r--absl/base/internal/unscaledcycleclock_config.h62
6 files changed, 142 insertions, 57 deletions
diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index bd023ad8..ded26d6a 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -114,6 +114,23 @@ cc_library(
)
cc_library(
+ name = "cycleclock_internal",
+ hdrs = [
+ "internal/cycleclock_config.h",
+ "internal/unscaledcycleclock_config.h",
+ ],
+ copts = ABSL_DEFAULT_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ visibility = [
+ "//absl:__subpackages__",
+ ],
+ deps = [
+ ":base_internal",
+ ":config",
+ ],
+)
+
+cc_library(
name = "dynamic_annotations",
srcs = [
"internal/dynamic_annotations.h",
@@ -237,6 +254,7 @@ cc_library(
":base_internal",
":config",
":core_headers",
+ ":cycleclock_internal",
":dynamic_annotations",
":log_severity",
":raw_logging_internal",
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index ed55093a..5c46ba32 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -181,6 +181,7 @@ absl_cc_library(
"call_once.h"
"casts.h"
"internal/cycleclock.h"
+ "internal/cycleclock_config.h"
"internal/low_level_scheduling.h"
"internal/per_thread_tls.h"
"internal/spinlock.h"
@@ -188,6 +189,7 @@ absl_cc_library(
"internal/thread_identity.h"
"internal/tsan_mutex_interface.h"
"internal/unscaledcycleclock.h"
+ "internal/unscaledcycleclock_config.h"
SRCS
"internal/cycleclock.cc"
"internal/spinlock.cc"
diff --git a/absl/base/internal/cycleclock.h b/absl/base/internal/cycleclock.h
index 9704e388..cbfdf579 100644
--- a/absl/base/internal/cycleclock.h
+++ b/absl/base/internal/cycleclock.h
@@ -47,6 +47,7 @@
#include "absl/base/attributes.h"
#include "absl/base/config.h"
+#include "absl/base/internal/cycleclock_config.h"
#include "absl/base/internal/unscaledcycleclock.h"
namespace absl {
@@ -76,25 +77,9 @@ class CycleClock {
#if ABSL_USE_UNSCALED_CYCLECLOCK
static CycleClockSourceFunc LoadCycleClockSource();
-#ifdef NDEBUG
-#ifdef ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
- // Not debug mode and the UnscaledCycleClock frequency is the CPU
- // frequency. Scale the CycleClock to prevent overflow if someone
- // tries to represent the time as cycles since the Unix epoch.
- static constexpr int32_t kShift = 1;
-#else
- // Not debug mode and the UnscaledCycleClock isn't operating at the
- // raw CPU frequency. There is no need to do any scaling, so don't
- // needlessly sacrifice precision.
- static constexpr int32_t kShift = 0;
-#endif
-#else // NDEBUG
- // In debug mode use a different shift to discourage depending on a
- // particular shift value.
- static constexpr int32_t kShift = 2;
-#endif // NDEBUG
+ static constexpr int32_t kShift = kCycleClockShift;
+ static constexpr double kFrequencyScale = kCycleClockFrequencyScale;
- static constexpr double kFrequencyScale = 1.0 / (1 << kShift);
ABSL_CONST_INIT static std::atomic<CycleClockSourceFunc> cycle_clock_source_;
#endif // ABSL_USE_UNSCALED_CYCLECLOC
diff --git a/absl/base/internal/cycleclock_config.h b/absl/base/internal/cycleclock_config.h
new file mode 100644
index 00000000..191112b5
--- /dev/null
+++ b/absl/base/internal/cycleclock_config.h
@@ -0,0 +1,55 @@
+// Copyright 2022 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_
+#define ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_
+
+#include <cstdint>
+
+#include "absl/base/config.h"
+#include "absl/base/internal/inline_variable.h"
+#include "absl/base/internal/unscaledcycleclock_config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace base_internal {
+
+#if ABSL_USE_UNSCALED_CYCLECLOCK
+#ifdef NDEBUG
+#ifdef ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
+// Not debug mode and the UnscaledCycleClock frequency is the CPU
+// frequency. Scale the CycleClock to prevent overflow if someone
+// tries to represent the time as cycles since the Unix epoch.
+ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 1);
+#else
+// Not debug mode and the UnscaledCycleClock isn't operating at the
+// raw CPU frequency. There is no need to do any scaling, so don't
+// needlessly sacrifice precision.
+ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 0);
+#endif
+#else // NDEBUG
+// In debug mode use a different shift to discourage depending on a
+// particular shift value.
+ABSL_INTERNAL_INLINE_CONSTEXPR(int32_t, kCycleClockShift, 2);
+#endif // NDEBUG
+
+ABSL_INTERNAL_INLINE_CONSTEXPR(double, kCycleClockFrequencyScale,
+ 1.0 / (1 << kCycleClockShift));
+#endif // ABSL_USE_UNSCALED_CYCLECLOC
+
+} // namespace base_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_BASE_INTERNAL_CYCLECLOCK_CONFIG_H_
diff --git a/absl/base/internal/unscaledcycleclock.h b/absl/base/internal/unscaledcycleclock.h
index 74bac8a0..cc1276ba 100644
--- a/absl/base/internal/unscaledcycleclock.h
+++ b/absl/base/internal/unscaledcycleclock.h
@@ -42,48 +42,11 @@
#include <TargetConditionals.h>
#endif
-#include "absl/base/port.h"
-
-// The following platforms have an implementation of a hardware counter.
-#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
- defined(__powerpc__) || defined(__ppc__) || defined(__riscv) || \
- defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
-#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 1
-#else
-#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 0
-#endif
-
-// The following platforms often disable access to the hardware
-// counter (through a sandbox) even if the underlying hardware has a
-// usable counter. The CycleTimer interface also requires a *scaled*
-// CycleClock that runs at atleast 1 MHz. We've found some Android
-// ARM64 devices where this is not the case, so we disable it by
-// default on Android ARM64.
-#if defined(__native_client__) || (defined(__APPLE__)) || \
- (defined(__ANDROID__) && defined(__aarch64__))
-#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 0
-#else
-#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 1
-#endif
-
-// UnscaledCycleClock is an optional internal feature.
-// Use "#if ABSL_USE_UNSCALED_CYCLECLOCK" to test for its presence.
-// Can be overridden at compile-time via -DABSL_USE_UNSCALED_CYCLECLOCK=0|1
-#if !defined(ABSL_USE_UNSCALED_CYCLECLOCK)
-#define ABSL_USE_UNSCALED_CYCLECLOCK \
- (ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION && \
- ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT)
-#endif
+#include "absl/base/config.h"
+#include "absl/base/internal/unscaledcycleclock_config.h"
#if ABSL_USE_UNSCALED_CYCLECLOCK
-// This macro can be used to test if UnscaledCycleClock::Frequency()
-// is NominalCPUFrequency() on a particular platform.
-#if (defined(__i386__) || defined(__x86_64__) || defined(__riscv) || \
- defined(_M_IX86) || defined(_M_X64))
-#define ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
-#endif
-
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace time_internal {
diff --git a/absl/base/internal/unscaledcycleclock_config.h b/absl/base/internal/unscaledcycleclock_config.h
new file mode 100644
index 00000000..24b324ac
--- /dev/null
+++ b/absl/base/internal/unscaledcycleclock_config.h
@@ -0,0 +1,62 @@
+// Copyright 2022 The Abseil Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_
+#define ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_
+
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+
+// The following platforms have an implementation of a hardware counter.
+#if defined(__i386__) || defined(__x86_64__) || defined(__aarch64__) || \
+ defined(__powerpc__) || defined(__ppc__) || defined(__riscv) || \
+ defined(_M_IX86) || (defined(_M_X64) && !defined(_M_ARM64EC))
+#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 1
+#else
+#define ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION 0
+#endif
+
+// The following platforms often disable access to the hardware
+// counter (through a sandbox) even if the underlying hardware has a
+// usable counter. The CycleTimer interface also requires a *scaled*
+// CycleClock that runs at atleast 1 MHz. We've found some Android
+// ARM64 devices where this is not the case, so we disable it by
+// default on Android ARM64.
+#if defined(__native_client__) || (defined(__APPLE__)) || \
+ (defined(__ANDROID__) && defined(__aarch64__))
+#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 0
+#else
+#define ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT 1
+#endif
+
+// UnscaledCycleClock is an optional internal feature.
+// Use "#if ABSL_USE_UNSCALED_CYCLECLOCK" to test for its presence.
+// Can be overridden at compile-time via -DABSL_USE_UNSCALED_CYCLECLOCK=0|1
+#if !defined(ABSL_USE_UNSCALED_CYCLECLOCK)
+#define ABSL_USE_UNSCALED_CYCLECLOCK \
+ (ABSL_HAVE_UNSCALED_CYCLECLOCK_IMPLEMENTATION && \
+ ABSL_USE_UNSCALED_CYCLECLOCK_DEFAULT)
+#endif
+
+#if ABSL_USE_UNSCALED_CYCLECLOCK
+// This macro can be used to test if UnscaledCycleClock::Frequency()
+// is NominalCPUFrequency() on a particular platform.
+#if (defined(__i386__) || defined(__x86_64__) || defined(__riscv) || \
+ defined(_M_IX86) || defined(_M_X64))
+#define ABSL_INTERNAL_UNSCALED_CYCLECLOCK_FREQUENCY_IS_CPU_FREQUENCY
+#endif
+#endif
+
+#endif // ABSL_BASE_INTERNAL_UNSCALEDCYCLECLOCK_CONFIG_H_