Changes imported from Abseil "staging" branch:

- 0320844dcd8219965647f86db7c6c7296e40e41e Introduce internal macros for inline variable emulation s... by Matt Calabrese <calabrese@google.com>
  - 85197d0105805e6aab3a0a648351cb1582a61be0 Internal change. by Alex Strelnikov <strel@google.com>

GitOrigin-RevId: 0320844dcd8219965647f86db7c6c7296e40e41e
Change-Id: I7dce37f6839ff099462951059a9047c5c9377638
This commit is contained in:
Abseil Team 2018-01-24 11:58:42 -08:00 committed by John Olson
parent dcf112f074
commit cf1db73d2a
10 changed files with 285 additions and 11 deletions

View file

@ -128,6 +128,7 @@ cc_library(
name = "base_internal",
hdrs = [
"internal/identity.h",
"internal/inline_variable.h",
"internal/invoke.h",
],
copts = ABSL_DEFAULT_COPTS,
@ -257,6 +258,22 @@ cc_test(
],
)
cc_test(
name = "inline_variable_test",
size = "small",
srcs = [
"inline_variable_test.cc",
"inline_variable_test_a.cc",
"inline_variable_test_b.cc",
"internal/inline_variable_testing.h",
],
copts = ABSL_TEST_COPTS,
deps = [
":base_internal",
"@com_google_googletest//:gtest_main",
],
)
cc_test(
name = "invoke_test",
size = "small",

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@ -37,6 +37,7 @@ list(APPEND BASE_INTERNAL_HEADERS
"internal/exception_safety_testing.h"
"internal/identity.h"
"internal/invoke.h"
"internal/inline_variable.h"
"internal/low_level_alloc.h"
"internal/low_level_scheduling.h"
"internal/malloc_extension.h"
@ -214,6 +215,26 @@ absl_test(
)
# test inline_variable_test
list(APPEND INLINE_VARIABLE_TEST_SRC
"internal/inline_variable_testing.h"
"inline_variable_test.cc"
"inline_variable_test_a.cc"
"inline_variable_test_b.cc"
)
set(INLINE_VARIABLE_TEST_PUBLIC_LIBRARIES absl::base)
absl_test(
TARGET
inline_variable_test
SOURCES
${INLINE_VARIABLE_TEST_SRC}
PUBLIC_LIBRARIES
${INLINE_VARIABLE_TEST_PUBLIC_LIBRARIES}
)
# test spinlock_test_common
set(SPINLOCK_TEST_COMMON_SRC "spinlock_test_common.cc")
set(SPINLOCK_TEST_COMMON_PUBLIC_LIBRARIES absl::base absl::synchronization)

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@ -0,0 +1,62 @@
// Copyright 2017 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
//
// http://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 <type_traits>
#include "absl/base/internal/inline_variable.h"
#include "absl/base/internal/inline_variable_testing.h"
#include "gtest/gtest.h"
namespace absl {
namespace inline_variable_testing_internal {
namespace {
TEST(InlineVariableTest, Constexpr) {
static_assert(inline_variable_foo.value == 5, "");
static_assert(other_inline_variable_foo.value == 5, "");
static_assert(inline_variable_int == 5, "");
static_assert(other_inline_variable_int == 5, "");
}
TEST(InlineVariableTest, DefaultConstructedIdentityEquality) {
EXPECT_EQ(get_foo_a().value, 5);
EXPECT_EQ(get_foo_b().value, 5);
EXPECT_EQ(&get_foo_a(), &get_foo_b());
}
TEST(InlineVariableTest, DefaultConstructedIdentityInequality) {
EXPECT_NE(&inline_variable_foo, &other_inline_variable_foo);
}
TEST(InlineVariableTest, InitializedIdentityEquality) {
EXPECT_EQ(get_int_a(), 5);
EXPECT_EQ(get_int_b(), 5);
EXPECT_EQ(&get_int_a(), &get_int_b());
}
TEST(InlineVariableTest, InitializedIdentityInequality) {
EXPECT_NE(&inline_variable_int, &other_inline_variable_int);
}
TEST(InlineVariableTest, FunPtrType) {
static_assert(
std::is_same<void(*)(),
std::decay<decltype(inline_variable_fun_ptr)>::type>::value,
"");
}
} // namespace
} // namespace inline_variable_testing_internal
} // namespace absl

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@ -12,16 +12,14 @@
// See the License for the specific language governing permissions and
// limitations under the License.
// -----------------------------------------------------------------------------
// File: ascii.h
// -----------------------------------------------------------------------------
//
#include "absl/utility/utility.h"
#include "absl/base/internal/inline_variable_testing.h"
namespace absl {
namespace inline_variable_testing_internal {
#ifndef ABSL_HAVE_STD_OPTIONAL
const in_place_t in_place{};
#endif
const Foo& get_foo_a() { return inline_variable_foo; }
const int& get_int_a() { return inline_variable_int; }
} // namespace inline_variable_testing_internal
} // namespace absl

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@ -0,0 +1,25 @@
// Copyright 2017 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
//
// http://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/inline_variable_testing.h"
namespace absl {
namespace inline_variable_testing_internal {
const Foo& get_foo_b() { return inline_variable_foo; }
const int& get_int_b() { return inline_variable_int; }
} // namespace inline_variable_testing_internal
} // namespace absl

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@ -0,0 +1,107 @@
// Copyright 2017 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
//
// http://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_INLINE_VARIABLE_EMULATION_H_
#define ABSL_BASE_INTERNAL_INLINE_VARIABLE_EMULATION_H_
#include <type_traits>
#include "absl/base/internal/identity.h"
// File:
// This file define a macro that allows the creation of or emulation of C++17
// inline variables based on whether or not the feature is supported.
////////////////////////////////////////////////////////////////////////////////
// Macro: ABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init)
//
// Description:
// Expands to the equivalent of an inline constexpr instance of the specified
// `type` and `name`, initialized to the value `init`. If the compiler being
// used is detected as supporting actual inline variables as a language
// feature, then the macro expands to an actual inline variable definition.
//
// Requires:
// `type` is a type that is usable in an extern variable declaration.
//
// Requires: `name` is a valid identifier
//
// Requires:
// `init` is an expression that can be used in the following definition:
// constexpr type name = init;
//
// Usage:
//
// // Equivalent to: `inline constexpr size_t variant_npos = -1;`
// ABSL_INTERNAL_INLINE_CONSTEXPR(size_t, variant_npos, -1);
//
// Differences in implementation:
// For a direct, language-level inline variable, decltype(name) will be the
// type that was specified along with const qualification, whereas for
// emulated inline variables, decltype(name) may be different (in practice
// it will likely be a reference type).
////////////////////////////////////////////////////////////////////////////////
#ifdef __cpp_inline_variables
// Clang's -Wmissing-variable-declarations option erroneously warned that
// inline constexpr objects need to be pre-declared. This has now been fixed,
// but we will need to support this workaround for people building with older
// versions of clang.
//
// Bug: https://bugs.llvm.org/show_bug.cgi?id=35862
//
// Note:
// identity_t is used here so that the const and name are in the
// appropriate place for pointer types, reference types, function pointer
// types, etc..
#if defined(__clang__)
#define ABSL_INTERNAL_EXTERN_DECL(type, name) \
extern const ::absl::internal::identity_t<type> name;
#else // Otherwise, just define the macro to do nothing.
#define ABSL_INTERNAL_EXTERN_DECL(type, name)
#endif // defined(__clang__)
// See above comment at top of file for details.
#define ABSL_INTERNAL_INLINE_CONSTEXPR(type, name, init) \
ABSL_INTERNAL_EXTERN_DECL(type, name) \
inline constexpr ::absl::internal::identity_t<type> name = init
#else
// See above comment at top of file for details.
//
// Note:
// identity_t is used here so that the const and name are in the
// appropriate place for pointer types, reference types, function pointer
// types, etc..
#define ABSL_INTERNAL_INLINE_CONSTEXPR(var_type, name, init) \
template <class /*AbslInternalDummy*/ = void> \
struct AbslInternalInlineVariableHolder##name { \
static constexpr ::absl::internal::identity_t<var_type> kInstance = init; \
}; \
\
template <class AbslInternalDummy> \
constexpr ::absl::internal::identity_t<var_type> \
AbslInternalInlineVariableHolder##name<AbslInternalDummy>::kInstance; \
\
static constexpr const ::absl::internal::identity_t<var_type>& \
name = /* NOLINT */ \
AbslInternalInlineVariableHolder##name<>::kInstance; \
static_assert(sizeof(void (*)(decltype(name))) != 0, \
"Silence unused variable warnings.")
#endif // __cpp_inline_variables
#endif // ABSL_BASE_INTERNAL_INLINE_VARIABLE_EMULATION_H_

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@ -0,0 +1,44 @@
// Copyright 2017 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
//
// http://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_INLINE_VARIABLE_TESTING_H_
#define ABSL_BASE_INLINE_VARIABLE_TESTING_H_
#include "absl/base/internal/inline_variable.h"
namespace absl {
namespace inline_variable_testing_internal {
struct Foo {
int value = 5;
};
ABSL_INTERNAL_INLINE_CONSTEXPR(Foo, inline_variable_foo, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(Foo, other_inline_variable_foo, {});
ABSL_INTERNAL_INLINE_CONSTEXPR(int, inline_variable_int, 5);
ABSL_INTERNAL_INLINE_CONSTEXPR(int, other_inline_variable_int, 5);
ABSL_INTERNAL_INLINE_CONSTEXPR(void(*)(), inline_variable_fun_ptr, nullptr);
const Foo& get_foo_a();
const Foo& get_foo_b();
const int& get_int_a();
const int& get_int_b();
} // namespace inline_variable_testing_internal
} // namespace absl
#endif // ABSL_BASE_INLINE_VARIABLE_TESTING_H_

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@ -10,7 +10,6 @@ licenses(["notice"]) # Apache 2.0
cc_library(
name = "utility",
srcs = ["utility.cc"],
hdrs = ["utility.h"],
copts = ABSL_DEFAULT_COPTS,
deps = [

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@ -22,7 +22,6 @@ list(APPEND UTILITY_PUBLIC_HEADERS
list(APPEND UTILITY_SRC
"utility.cc"
${UTILITY_PUBLIC_HEADERS}
)

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@ -45,6 +45,7 @@
#include <utility>
#include "absl/base/config.h"
#include "absl/base/internal/inline_variable.h"
#include "absl/base/internal/invoke.h"
#include "absl/meta/type_traits.h"
@ -155,7 +156,8 @@ using std::in_place;
// `absl::optional`, designed to be a drop-in replacement for C++17's
// `std::in_place_t`.
struct in_place_t {};
extern const in_place_t in_place;
ABSL_INTERNAL_INLINE_CONSTEXPR(in_place_t, in_place, {});
#endif // ABSL_HAVE_STD_OPTIONAL