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
diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel
index 1778f4f..9bb7bfa 100644
--- a/absl/base/BUILD.bazel
+++ b/absl/base/BUILD.bazel
@@ -128,6 +128,7 @@
name = "base_internal",
hdrs = [
"internal/identity.h",
+ "internal/inline_variable.h",
"internal/invoke.h",
],
copts = ABSL_DEFAULT_COPTS,
@@ -258,6 +259,22 @@
)
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",
srcs = ["invoke_test.cc"],
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index d306616..9d2de55 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -37,6 +37,7 @@
"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 @@
)
+# 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)
diff --git a/absl/base/inline_variable_test.cc b/absl/base/inline_variable_test.cc
new file mode 100644
index 0000000..5499189
--- /dev/null
+++ b/absl/base/inline_variable_test.cc
@@ -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
diff --git a/absl/utility/utility.cc b/absl/base/inline_variable_test_a.cc
similarity index 68%
copy from absl/utility/utility.cc
copy to absl/base/inline_variable_test_a.cc
index fce79f5..a3bf3b6 100644
--- a/absl/utility/utility.cc
+++ b/absl/base/inline_variable_test_a.cc
@@ -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
diff --git a/absl/utility/utility.cc b/absl/base/inline_variable_test_b.cc
similarity index 68%
rename from absl/utility/utility.cc
rename to absl/base/inline_variable_test_b.cc
index fce79f5..b4b9393 100644
--- a/absl/utility/utility.cc
+++ b/absl/base/inline_variable_test_b.cc
@@ -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_b() { return inline_variable_foo; }
+const int& get_int_b() { return inline_variable_int; }
+
+} // namespace inline_variable_testing_internal
} // namespace absl
diff --git a/absl/base/internal/inline_variable.h b/absl/base/internal/inline_variable.h
new file mode 100644
index 0000000..f7bb8c5
--- /dev/null
+++ b/absl/base/internal/inline_variable.h
@@ -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_
diff --git a/absl/base/internal/inline_variable_testing.h b/absl/base/internal/inline_variable_testing.h
new file mode 100644
index 0000000..a0dd2bb
--- /dev/null
+++ b/absl/base/internal/inline_variable_testing.h
@@ -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_
diff --git a/absl/utility/BUILD.bazel b/absl/utility/BUILD.bazel
index 6298462..c01b49b 100644
--- a/absl/utility/BUILD.bazel
+++ b/absl/utility/BUILD.bazel
@@ -10,7 +10,6 @@
cc_library(
name = "utility",
- srcs = ["utility.cc"],
hdrs = ["utility.h"],
copts = ABSL_DEFAULT_COPTS,
deps = [
diff --git a/absl/utility/CMakeLists.txt b/absl/utility/CMakeLists.txt
index daf3417..50a5d5c 100644
--- a/absl/utility/CMakeLists.txt
+++ b/absl/utility/CMakeLists.txt
@@ -22,7 +22,6 @@
list(APPEND UTILITY_SRC
- "utility.cc"
${UTILITY_PUBLIC_HEADERS}
)
diff --git a/absl/utility/utility.h b/absl/utility/utility.h
index d37f4c3..1943c4a 100644
--- a/absl/utility/utility.h
+++ b/absl/utility/utility.h
@@ -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 @@
// `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
