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-rw-r--r--absl/base/BUILD.bazel25
-rw-r--r--absl/base/CMakeLists.txt25
-rw-r--r--absl/base/internal/bits.h24
-rw-r--r--absl/base/internal/fast_type_id.h48
-rw-r--r--absl/base/internal/fast_type_id_test.cc123
5 files changed, 233 insertions, 12 deletions
diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 24dab791..1af9e45e 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -750,3 +750,28 @@ cc_binary(
"@com_github_google_benchmark//:benchmark_main",
],
)
+
+cc_library(
+ name = "fast_type_id",
+ hdrs = ["internal/fast_type_id.h"],
+ copts = ABSL_DEFAULT_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ visibility = [
+ "//absl:__subpackages__",
+ ],
+ deps = [
+ ":config",
+ ],
+)
+
+cc_test(
+ name = "fast_type_id_test",
+ size = "small",
+ srcs = ["internal/fast_type_id_test.cc"],
+ copts = ABSL_TEST_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ ":fast_type_id",
+ "@com_google_googletest//:gtest_main",
+ ],
+)
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 4230d2e7..54549920 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -674,3 +674,28 @@ absl_cc_test(
gmock
gtest_main
)
+
+absl_cc_library(
+ NAME
+ fast_type_id
+ HDRS
+ "internal/fast_type_id.h"
+ COPTS
+ ${ABSL_DEFAULT_COPTS}
+ LINKOPTS
+ ${ABSL_DEFAULT_LINKOPTS}
+ DEPS
+ absl::config
+)
+
+absl_cc_test(
+ NAME
+ fast_type_id_test
+ SRCS
+ "internal/fast_type_id_test.cc"
+ COPTS
+ ${ABSL_TEST_COPTS}
+ DEPS
+ absl::fast_type_id
+ gtest_main
+)
diff --git a/absl/base/internal/bits.h b/absl/base/internal/bits.h
index 8b03453c..14c51d8b 100644
--- a/absl/base/internal/bits.h
+++ b/absl/base/internal/bits.h
@@ -24,7 +24,7 @@
// Clang on Windows has __builtin_clzll; otherwise we need to use the
// windows intrinsic functions.
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) && !defined(__clang__)
#include <intrin.h>
#if defined(_M_X64)
#pragma intrinsic(_BitScanReverse64)
@@ -36,7 +36,7 @@
#include "absl/base/attributes.h"
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) && !defined(__clang__)
// We can achieve something similar to attribute((always_inline)) with MSVC by
// using the __forceinline keyword, however this is not perfect. MSVC is
// much less aggressive about inlining, and even with the __forceinline keyword.
@@ -73,14 +73,14 @@ ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros64Slow(uint64_t n) {
}
ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros64(uint64_t n) {
-#if defined(_MSC_VER) && defined(_M_X64)
+#if defined(_MSC_VER) && !defined(__clang__) && defined(_M_X64)
// MSVC does not have __buitin_clzll. Use _BitScanReverse64.
unsigned long result = 0; // NOLINT(runtime/int)
if (_BitScanReverse64(&result, n)) {
return 63 - result;
}
return 64;
-#elif defined(_MSC_VER)
+#elif defined(_MSC_VER) && !defined(__clang__)
// MSVC does not have __buitin_clzll. Compose two calls to _BitScanReverse
unsigned long result = 0; // NOLINT(runtime/int)
if ((n >> 32) && _BitScanReverse(&result, n >> 32)) {
@@ -90,7 +90,7 @@ ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros64(uint64_t n) {
return 63 - result;
}
return 64;
-#elif defined(__GNUC__)
+#elif defined(__GNUC__) || defined(__clang__)
// Use __builtin_clzll, which uses the following instructions:
// x86: bsr
// ARM64: clz
@@ -126,13 +126,13 @@ ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros32Slow(uint64_t n) {
}
ABSL_BASE_INTERNAL_FORCEINLINE int CountLeadingZeros32(uint32_t n) {
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) && !defined(__clang__)
unsigned long result = 0; // NOLINT(runtime/int)
if (_BitScanReverse(&result, n)) {
return 31 - result;
}
return 32;
-#elif defined(__GNUC__)
+#elif defined(__GNUC__) || defined(__clang__)
// Use __builtin_clz, which uses the following instructions:
// x86: bsr
// ARM64: clz
@@ -163,11 +163,11 @@ ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero64Slow(uint64_t n) {
}
ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero64(uint64_t n) {
-#if defined(_MSC_VER) && defined(_M_X64)
+#if defined(_MSC_VER) && !defined(__clang__) && defined(_M_X64)
unsigned long result = 0; // NOLINT(runtime/int)
_BitScanForward64(&result, n);
return result;
-#elif defined(_MSC_VER)
+#elif defined(_MSC_VER) && !defined(__clang__)
unsigned long result = 0; // NOLINT(runtime/int)
if (static_cast<uint32_t>(n) == 0) {
_BitScanForward(&result, n >> 32);
@@ -175,7 +175,7 @@ ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero64(uint64_t n) {
}
_BitScanForward(&result, n);
return result;
-#elif defined(__GNUC__)
+#elif defined(__GNUC__) || defined(__clang__)
static_assert(sizeof(unsigned long long) == sizeof(n), // NOLINT(runtime/int)
"__builtin_ctzll does not take 64-bit arg");
return __builtin_ctzll(n);
@@ -196,11 +196,11 @@ ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero32Slow(uint32_t n) {
}
ABSL_BASE_INTERNAL_FORCEINLINE int CountTrailingZerosNonZero32(uint32_t n) {
-#if defined(_MSC_VER)
+#if defined(_MSC_VER) && !defined(__clang__)
unsigned long result = 0; // NOLINT(runtime/int)
_BitScanForward(&result, n);
return result;
-#elif defined(__GNUC__)
+#elif defined(__GNUC__) || defined(__clang__)
static_assert(sizeof(int) == sizeof(n),
"__builtin_ctz does not take 32-bit arg");
return __builtin_ctz(n);
diff --git a/absl/base/internal/fast_type_id.h b/absl/base/internal/fast_type_id.h
new file mode 100644
index 00000000..3db59e83
--- /dev/null
+++ b/absl/base/internal/fast_type_id.h
@@ -0,0 +1,48 @@
+//
+// Copyright 2020 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_FAST_TYPE_ID_H_
+#define ABSL_BASE_INTERNAL_FAST_TYPE_ID_H_
+
+#include "absl/base/config.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace base_internal {
+
+template <typename Type>
+struct FastTypeTag {
+ constexpr static char dummy_var = 0;
+};
+
+template <typename Type>
+constexpr char FastTypeTag<Type>::dummy_var;
+
+// FastTypeId<Type>() evaluates at compile/link-time to a unique pointer for the
+// passed-in type. These are meant to be good match for keys into maps or
+// straight up comparisons.
+using FastTypeIdType = const void*;
+
+template <typename Type>
+constexpr inline FastTypeIdType FastTypeId() {
+ return &FastTypeTag<Type>::dummy_var;
+}
+
+} // namespace base_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_BASE_INTERNAL_FAST_TYPE_ID_H_
diff --git a/absl/base/internal/fast_type_id_test.cc b/absl/base/internal/fast_type_id_test.cc
new file mode 100644
index 00000000..16f3c145
--- /dev/null
+++ b/absl/base/internal/fast_type_id_test.cc
@@ -0,0 +1,123 @@
+// Copyright 2020 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.
+
+#include "absl/base/internal/fast_type_id.h"
+
+#include <cstdint>
+#include <map>
+#include <vector>
+
+#include "gtest/gtest.h"
+
+namespace {
+namespace bi = absl::base_internal;
+
+// NOLINTNEXTLINE
+#define PRIM_TYPES(A) \
+ A(bool) \
+ A(short) \
+ A(unsigned short) \
+ A(int) \
+ A(unsigned int) \
+ A(long) \
+ A(unsigned long) \
+ A(long long) \
+ A(unsigned long long) \
+ A(float) \
+ A(double) \
+ A(long double)
+
+TEST(FastTypeIdTest, PrimitiveTypes) {
+ bi::FastTypeIdType type_ids[] = {
+#define A(T) bi::FastTypeId<T>(),
+ PRIM_TYPES(A)
+#undef A
+#define A(T) bi::FastTypeId<const T>(),
+ PRIM_TYPES(A)
+#undef A
+#define A(T) bi::FastTypeId<volatile T>(),
+ PRIM_TYPES(A)
+#undef A
+#define A(T) bi::FastTypeId<const volatile T>(),
+ PRIM_TYPES(A)
+#undef A
+ };
+ size_t total_type_ids = sizeof(type_ids) / sizeof(bi::FastTypeIdType);
+
+ for (int i = 0; i < total_type_ids; ++i) {
+ EXPECT_EQ(type_ids[i], type_ids[i]);
+ for (int j = 0; j < i; ++j) {
+ EXPECT_NE(type_ids[i], type_ids[j]);
+ }
+ }
+}
+
+#define FIXED_WIDTH_TYPES(A) \
+ A(int8_t) \
+ A(uint8_t) \
+ A(int16_t) \
+ A(uint16_t) \
+ A(int32_t) \
+ A(uint32_t) \
+ A(int64_t) \
+ A(uint64_t)
+
+TEST(FastTypeIdTest, FixedWidthTypes) {
+ bi::FastTypeIdType type_ids[] = {
+#define A(T) bi::FastTypeId<T>(),
+ FIXED_WIDTH_TYPES(A)
+#undef A
+#define A(T) bi::FastTypeId<const T>(),
+ FIXED_WIDTH_TYPES(A)
+#undef A
+#define A(T) bi::FastTypeId<volatile T>(),
+ FIXED_WIDTH_TYPES(A)
+#undef A
+#define A(T) bi::FastTypeId<const volatile T>(),
+ FIXED_WIDTH_TYPES(A)
+#undef A
+ };
+ size_t total_type_ids = sizeof(type_ids) / sizeof(bi::FastTypeIdType);
+
+ for (int i = 0; i < total_type_ids; ++i) {
+ EXPECT_EQ(type_ids[i], type_ids[i]);
+ for (int j = 0; j < i; ++j) {
+ EXPECT_NE(type_ids[i], type_ids[j]);
+ }
+ }
+}
+
+TEST(FastTypeIdTest, AliasTypes) {
+ using int_alias = int;
+ EXPECT_EQ(bi::FastTypeId<int_alias>(), bi::FastTypeId<int>());
+}
+
+TEST(FastTypeIdTest, TemplateSpecializations) {
+ EXPECT_NE(bi::FastTypeId<std::vector<int>>(),
+ bi::FastTypeId<std::vector<long>>());
+
+ EXPECT_NE((bi::FastTypeId<std::map<int, float>>()),
+ (bi::FastTypeId<std::map<int, double>>()));
+}
+
+struct Base {};
+struct Derived : Base {};
+struct PDerived : private Base {};
+
+TEST(FastTypeIdTest, Inheritance) {
+ EXPECT_NE(bi::FastTypeId<Base>(), bi::FastTypeId<Derived>());
+ EXPECT_NE(bi::FastTypeId<Base>(), bi::FastTypeId<PDerived>());
+}
+
+} // namespace
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-08 01:03:58 +0000