diff options
Diffstat (limited to 'absl')
34 files changed, 442 insertions, 153 deletions
diff --git a/absl/base/BUILD.bazel b/absl/base/BUILD.bazel index 87a6d3e6..2e023ef2 100644 --- a/absl/base/BUILD.bazel +++ b/absl/base/BUILD.bazel @@ -121,6 +121,7 @@ cc_library( ":config", ":core_headers", ":dynamic_annotations", + ":spinlock_wait", ], ) @@ -192,6 +193,7 @@ cc_library( deps = [ ":base", ":config", + ":core_headers", ], ) @@ -236,6 +238,8 @@ cc_library( copts = ABSL_TEST_COPTS, deps = [ ":base", + ":core_headers", + ":spinlock_wait", "//absl/synchronization", "@com_google_googletest//:gtest", ], @@ -249,6 +253,8 @@ cc_test( copts = ABSL_TEST_COPTS, deps = [ ":base", + ":core_headers", + ":spinlock_wait", "//absl/synchronization", "@com_google_googletest//:gtest_main", ], @@ -342,6 +348,7 @@ cc_test( }), deps = [ ":base", + ":core_headers", "//absl/synchronization", ] + select(GUNIT_MAIN_DEPS_SELECTOR), ) diff --git a/absl/base/attributes.h b/absl/base/attributes.h index 5eecdabe..c2155a4e 100644 --- a/absl/base/attributes.h +++ b/absl/base/attributes.h @@ -12,39 +12,61 @@ // See the License for the specific language governing permissions and // limitations under the License. // -// Various macros for C++ attributes +// This header file defines macros for declaring attributes for functions, +// types, and variables. +// +// These macros are used within Abseil and allow the compiler to optimize, where +// applicable, certain function calls. +// // This file is used for both C and C++! // // Most macros here are exposing GCC or Clang features, and are stubbed out for // other compilers. +// // GCC attributes documentation: -// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Function-Attributes.html -// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Variable-Attributes.html -// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Type-Attributes.html -// -// Most attributes in this file are already supported by GCC 4.7. -// However, some of them are not supported in older version of Clang. -// Thus, we check __has_attribute() first. If the check fails, we check if we -// are on GCC and assume the attribute exists on GCC (which is verified on GCC -// 4.7). -// -// For sanitizer-related attributes, define the following macros -// using -D along with the given value for -fsanitize: -// - ADDRESS_SANITIZER with -fsanitize=address (GCC 4.8+, Clang) -// - MEMORY_SANITIZER with -fsanitize=memory (Clang) -// - THREAD_SANITIZER with -fsanitize=thread (GCC 4.8+, Clang) -// - UNDEFINED_BEHAVIOR_SANITIZER with -fsanitize=undefined (GCC 4.9+, Clang) -// - CONTROL_FLOW_INTEGRITY with -fsanitize=cfi (Clang) -// Since these are only supported by GCC and Clang now, we only check for -// __GNUC__ (GCC or Clang) and the above macros. +// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Function-Attributes.html +// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Variable-Attributes.html +// https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Type-Attributes.html +// +// Most attributes in this file are already supported by GCC 4.7. However, some +// of them are not supported in older version of Clang. Thus, we check +// `__has_attribute()` first. If the check fails, we check if we are on GCC and +// assume the attribute exists on GCC (which is verified on GCC 4.7). +// +// ----------------------------------------------------------------------------- +// Sanitizer Attributes +// ----------------------------------------------------------------------------- +// +// Sanitizer-related attributes are not "defined" in this file (and indeed +// are not defined as such in any file). To utilize the following +// sanitizer-related attributes within your builds, define the following macros +// within your build using a `-D` flag, along with the given value for +// `-fsanitize`: +// +// * `ADDRESS_SANITIZER` + `-fsanitize=address` (Clang, GCC 4.8) +// * `MEMORY_SANITIZER` + `-fsanitize=memory` (Clang-only) +// * `THREAD_SANITIZER + `-fsanitize=thread` (Clang, GCC 4.8+) +// * `UNDEFINED_BEHAVIOR_SANITIZER` + `-fsanitize=undefined` (Clang, GCC 4.9+) +// * `CONTROL_FLOW_INTEGRITY` + -fsanitize=cfi (Clang-only) +// +// Example: +// +// // Enable branches in the Abseil code that are tagged for ASan: +// $ bazel -D ADDRESS_SANITIZER -fsanitize=address *target* +// +// Since these macro names are only supported by GCC and Clang, we only check +// for `__GNUC__` (GCC or Clang) and the above macros. #ifndef ABSL_BASE_ATTRIBUTES_H_ #define ABSL_BASE_ATTRIBUTES_H_ -// ABSL_HAVE_ATTRIBUTE is a function-like feature checking macro. -// It's a wrapper around __has_attribute, which is defined by GCC 5+ and Clang. -// It evaluates to a nonzero constant integer if the attribute is supported -// or 0 if not. -// It evaluates to zero if __has_attribute is not defined by the compiler. +// ABSL_HAVE_ATTRIBUTE +// +// A function-like feature checking macro that is a wrapper around +// `__has_attribute`, which is defined by GCC 5+ and Clang and evaluates to a +// nonzero constant integer if the attribute is supported or 0 if not. +// +// It evaluates to zero if `__has_attribute` is not defined by the compiler. +// // GCC: https://gcc.gnu.org/gcc-5/changes.html // Clang: https://clang.llvm.org/docs/LanguageExtensions.html #ifdef __has_attribute @@ -53,11 +75,12 @@ #define ABSL_HAVE_ATTRIBUTE(x) 0 #endif -// ABSL_HAVE_CPP_ATTRIBUTE is a function-like feature checking macro that -// accepts C++11 style attributes. It's a wrapper around __has_cpp_attribute, -// defined by ISO C++ SD-6 +// ABSL_HAVE_CPP_ATTRIBUTE +// +// A function-like feature checking macro that accepts C++11 style attributes. +// It's a wrapper around `__has_cpp_attribute`, defined by ISO C++ SD-6 // (http://en.cppreference.com/w/cpp/experimental/feature_test). If we don't -// find __has_cpp_attribute, will evaluate to 0. +// find `__has_cpp_attribute`, will evaluate to 0. #if defined(__cplusplus) && defined(__has_cpp_attribute) // NOTE: requiring __cplusplus above should not be necessary, but // works around https://bugs.llvm.org/show_bug.cgi?id=23435. @@ -69,15 +92,18 @@ // ----------------------------------------------------------------------------- // Function Attributes // ----------------------------------------------------------------------------- +// // GCC: https://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html // Clang: https://clang.llvm.org/docs/AttributeReference.html -// ABSL_PRINTF_ATTRIBUTE, ABSL_SCANF_ATTRIBUTE -// Tell the compiler to do printf format std::string checking if the +// ABSL_PRINTF_ATTRIBUTE +// ABSL_SCANF_ATTRIBUTE +// +// Tells the compiler to perform `printf` format std::string checking if the // compiler supports it; see the 'format' attribute in // <http://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/Function-Attributes.html>. // -// N.B.: As the GCC manual states, "[s]ince non-static C++ methods +// Note: As the GCC manual states, "[s]ince non-static C++ methods // have an implicit 'this' argument, the arguments of such methods // should be counted from two, not one." #if ABSL_HAVE_ATTRIBUTE(format) || (defined(__GNUC__) && !defined(__clang__)) @@ -90,9 +116,10 @@ #define ABSL_SCANF_ATTRIBUTE(string_index, first_to_check) #endif -// ABSL_ATTRIBUTE_ALWAYS_INLINE, ABSL_ATTRIBUTE_NOINLINE -// For functions we want to force inline or not inline. -// Introduced in gcc 3.1. +// ABSL_ATTRIBUTE_ALWAYS_INLINE +// ABSL_ATTRIBUTE_NOINLINE +// +// Forces functions to either inline or not inline. Introduced in gcc 3.1. #if ABSL_HAVE_ATTRIBUTE(always_inline) || \ (defined(__GNUC__) && !defined(__clang__)) #define ABSL_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline)) @@ -109,7 +136,8 @@ #endif // ABSL_ATTRIBUTE_NO_TAIL_CALL -// Prevent the compiler from optimizing away stack frames for functions which +// +// Prevents the compiler from optimizing away stack frames for functions which // end in a call to another function. #if ABSL_HAVE_ATTRIBUTE(disable_tail_calls) #define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 1 @@ -122,8 +150,10 @@ #define ABSL_ATTRIBUTE_NO_TAIL_CALL #define ABSL_HAVE_ATTRIBUTE_NO_TAIL_CALL 0 #endif + // ABSL_ATTRIBUTE_WEAK -// For weak functions +// +// Tags a function as weak for the purposes of compilation and linking. #if ABSL_HAVE_ATTRIBUTE(weak) || (defined(__GNUC__) && !defined(__clang__)) #undef ABSL_ATTRIBUTE_WEAK #define ABSL_ATTRIBUTE_WEAK __attribute__((weak)) @@ -132,9 +162,11 @@ #define ABSL_ATTRIBUTE_WEAK #define ABSL_HAVE_ATTRIBUTE_WEAK 0 #endif + // ABSL_ATTRIBUTE_NONNULL -// Tell the compiler either that a particular function parameter -// should be a non-null pointer, or that all pointer arguments should +// +// Tells the compiler either (a) that a particular function parameter +// should be a non-null pointer, or (b) that all pointer arguments should // be non-null. // // Note: As the GCC manual states, "[s]ince non-static C++ methods @@ -142,10 +174,13 @@ // should be counted from two, not one." // // Args are indexed starting at 1. -// For non-static class member functions, the implicit "this" argument -// is arg 1, and the first explicit argument is arg 2. -// For static class member functions, there is no implicit "this", and -// the first explicit argument is arg 1. +// +// For non-static class member functions, the implicit `this` argument +// is arg 1, and the first explicit argument is arg 2. For static class member +// functions, there is no implicit `this`, and the first explicit argument is +// arg 1. +// +// Example: // // /* arg_a cannot be null, but arg_b can */ // void Function(void* arg_a, void* arg_b) ABSL_ATTRIBUTE_NONNULL(1); @@ -171,8 +206,10 @@ #else #define ABSL_ATTRIBUTE_NONNULL(...) #endif + // ABSL_ATTRIBUTE_NORETURN -// Tell the compiler that a given function never returns +// +// Tells the compiler that a given function never returns. #if ABSL_HAVE_ATTRIBUTE(noreturn) || (defined(__GNUC__) && !defined(__clang__)) #define ABSL_ATTRIBUTE_NORETURN __attribute__((noreturn)) #elif defined(_MSC_VER) @@ -180,8 +217,10 @@ #else #define ABSL_ATTRIBUTE_NORETURN #endif + // ABSL_ATTRIBUTE_NO_SANITIZE_ADDRESS -// Tell AddressSanitizer (or other memory testing tools) to ignore a given +// +// Tells the AddressSanitizer (or other memory testing tools) to ignore a given // function. Useful for cases when a function reads random locations on stack, // calls _exit from a cloned subprocess, deliberately accesses buffer // out of bounds or does other scary things with memory. @@ -194,11 +233,12 @@ #endif // ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY -// Tell MemorySanitizer to relax the handling of a given function. All "Use of -// uninitialized value" warnings from such functions will be suppressed, and all -// values loaded from memory will be considered fully initialized. -// This is similar to the ADDRESS_SANITIZER attribute above, but deals with -// initializedness rather than addressability issues. +// +// Tells the MemorySanitizer to relax the handling of a given function. All +// "Use of uninitialized value" warnings from such functions will be suppressed, +// and all values loaded from memory will be considered fully initialized. +// This attribute is similar to the ADDRESS_SANITIZER attribute above, but deals +// with initialized-ness rather than addressability issues. // NOTE: MemorySanitizer(msan) is supported by Clang but not GCC. #if defined(__GNUC__) && defined(MEMORY_SANITIZER) #define ABSL_ATTRIBUTE_NO_SANITIZE_MEMORY __attribute__((no_sanitize_memory)) @@ -207,8 +247,8 @@ #endif // ABSL_ATTRIBUTE_NO_SANITIZE_THREAD -// Tell ThreadSanitizer to not instrument a given function. -// If you are adding this attribute, please cc dynamic-tools@ on the cl. +// +// Tells the ThreadSanitizer to not instrument a given function. // NOTE: GCC supports ThreadSanitizer(tsan) since 4.8. // https://gcc.gnu.org/gcc-4.8/changes.html #if defined(__GNUC__) && defined(THREAD_SANITIZER) @@ -218,7 +258,8 @@ #endif // ABSL_ATTRIBUTE_NO_SANITIZE_UNDEFINED -// Tell UndefinedSanitizer to ignore a given function. Useful for cases +// +// Tells the UndefinedSanitizer to ignore a given function. Useful for cases // where certain behavior (eg. devision by zero) is being used intentionally. // NOTE: GCC supports UndefinedBehaviorSanitizer(ubsan) since 4.9. // https://gcc.gnu.org/gcc-4.9/changes.html @@ -231,7 +272,8 @@ #endif // ABSL_ATTRIBUTE_NO_SANITIZE_CFI -// Tell ControlFlowIntegrity sanitizer to not instrument a given function. +// +// Tells the ControlFlowIntegrity sanitizer to not instrument a given function. // See https://clang.llvm.org/docs/ControlFlowIntegrity.html for details. #if defined(__GNUC__) && defined(CONTROL_FLOW_INTEGRITY) #define ABSL_ATTRIBUTE_NO_SANITIZE_CFI __attribute__((no_sanitize("cfi"))) @@ -239,33 +281,42 @@ #define ABSL_ATTRIBUTE_NO_SANITIZE_CFI #endif -// ABSL_ATTRIBUTE_SECTION -// Labeled sections are not supported on Darwin/iOS. +// ABSL_HAVE_ATTRIBUTE_SECTION +// +// Indicates whether labeled sections are supported. Labeled sections are not +// supported on Darwin/iOS. #ifdef ABSL_HAVE_ATTRIBUTE_SECTION #error ABSL_HAVE_ATTRIBUTE_SECTION cannot be directly set #elif (ABSL_HAVE_ATTRIBUTE(section) || \ (defined(__GNUC__) && !defined(__clang__))) && \ !defined(__APPLE__) #define ABSL_HAVE_ATTRIBUTE_SECTION 1 + +// ABSL_ATTRIBUTE_SECTION // -// Tell the compiler/linker to put a given function into a section and define -// "__start_ ## name" and "__stop_ ## name" symbols to bracket the section. -// This functionality is supported by GNU linker. -// Any function with ABSL_ATTRIBUTE_SECTION must not be inlined, or it will -// be placed into whatever section its caller is placed into. +// Tells the compiler/linker to put a given function into a section and define +// `__start_ ## name` and `__stop_ ## name` symbols to bracket the section. +// This functionality is supported by GNU linker. Any function annotated with +// `ABSL_ATTRIBUTE_SECTION` must not be inlined, or it will be placed into +// whatever section its caller is placed into. // #ifndef ABSL_ATTRIBUTE_SECTION #define ABSL_ATTRIBUTE_SECTION(name) \ __attribute__((section(#name))) __attribute__((noinline)) #endif -// Tell the compiler/linker to put a given variable into a section and define -// "__start_ ## name" and "__stop_ ## name" symbols to bracket the section. + +// ABSL_ATTRIBUTE_SECTION_VARIABLE +// +// Tells the compiler/linker to put a given variable into a section and define +// `__start_ ## name` and `__stop_ ## name` symbols to bracket the section. // This functionality is supported by GNU linker. #ifndef ABSL_ATTRIBUTE_SECTION_VARIABLE #define ABSL_ATTRIBUTE_SECTION_VARIABLE(name) __attribute__((section(#name))) #endif + +// ABSL_DECLARE_ATTRIBUTE_SECTION_VARS // -// Weak section declaration to be used as a global declaration +// A weak section declaration to be used as a global declaration // for ABSL_ATTRIBUTE_SECTION_START|STOP(name) to compile and link // even without functions with ABSL_ATTRIBUTE_SECTION(name). // ABSL_DEFINE_ATTRIBUTE_SECTION should be in the exactly one file; it's @@ -281,7 +332,9 @@ #define ABSL_DEFINE_ATTRIBUTE_SECTION_VARS(name) #endif -// Return void* pointers to start/end of a section of code with +// ABSL_ATTRIBUTE_SECTION_START +// +// Returns `void*` pointers to start/end of a section of code with // functions having ABSL_ATTRIBUTE_SECTION(name). // Returns 0 if no such functions exist. // One must ABSL_DECLARE_ATTRIBUTE_SECTION_VARS(name) for this to compile and @@ -306,6 +359,7 @@ #endif // ABSL_ATTRIBUTE_SECTION // ABSL_ATTRIBUTE_STACK_ALIGN_FOR_OLD_LIBC +// // Support for aligning the stack on 32-bit x86. #if ABSL_HAVE_ATTRIBUTE(force_align_arg_pointer) || \ (defined(__GNUC__) && !defined(__clang__)) @@ -326,10 +380,13 @@ #endif // ABSL_MUST_USE_RESULT -// Tell the compiler to warn about unused return values for functions declared +// +// Tells the compiler to warn about unused return values for functions declared // with this macro. The macro must appear as the very first part of a function // declaration or definition: // +// Example: +// // ABSL_MUST_USE_RESULT Sprocket* AllocateSprocket(); // // This placement has the broadest compatibility with GCC, Clang, and MSVC, with @@ -350,10 +407,14 @@ #endif // ABSL_ATTRIBUTE_HOT, ABSL_ATTRIBUTE_COLD -// Tell GCC that a function is hot or cold. GCC can use this information to +// +// Tells GCC that a function is hot or cold. GCC can use this information to // improve static analysis, i.e. a conditional branch to a cold function // is likely to be not-taken. -// This annotation is used for function declarations, e.g.: +// This annotation is used for function declarations. +// +// Example: +// // int foo() ABSL_ATTRIBUTE_HOT; #if ABSL_HAVE_ATTRIBUTE(hot) || (defined(__GNUC__) && !defined(__clang__)) #define ABSL_ATTRIBUTE_HOT __attribute__((hot)) @@ -382,12 +443,12 @@ // // These attributes only take effect when the following conditions are met: // -// - The file/target is built in at least C++11 mode, with a Clang compiler -// that supports XRay attributes. -// - The file/target is built with the -fxray-instrument flag set for the -// Clang/LLVM compiler. -// - The function is defined in the translation unit (the compiler honors the -// attribute in either the definition or the declaration, and must match). +// * The file/target is built in at least C++11 mode, with a Clang compiler +// that supports XRay attributes. +// * The file/target is built with the -fxray-instrument flag set for the +// Clang/LLVM compiler. +// * The function is defined in the translation unit (the compiler honors the +// attribute in either the definition or the declaration, and must match). // // There are cases when, even when building with XRay instrumentation, users // might want to control specifically which functions are instrumented for a @@ -422,7 +483,8 @@ // ----------------------------------------------------------------------------- // ABSL_ATTRIBUTE_UNUSED -// Prevent the compiler from complaining about or optimizing away variables +// +// Prevents the compiler from complaining about or optimizing away variables // that appear unused. #if ABSL_HAVE_ATTRIBUTE(unused) || (defined(__GNUC__) && !defined(__clang__)) #undef ABSL_ATTRIBUTE_UNUSED @@ -430,8 +492,10 @@ #else #define ABSL_ATTRIBUTE_UNUSED #endif + // ABSL_ATTRIBUTE_INITIAL_EXEC -// Tell the compiler to use "initial-exec" mode for a thread-local variable. +// +// Tells the compiler to use "initial-exec" mode for a thread-local variable. // See http://people.redhat.com/drepper/tls.pdf for the gory details. #if ABSL_HAVE_ATTRIBUTE(tls_model) || (defined(__GNUC__) && !defined(__clang__)) #define ABSL_ATTRIBUTE_INITIAL_EXEC __attribute__((tls_model("initial-exec"))) @@ -440,7 +504,8 @@ #endif // ABSL_ATTRIBUTE_PACKED -// Prevent the compiler from padding a structure to natural alignment +// +// Prevents the compiler from padding a structure to natural alignment #if ABSL_HAVE_ATTRIBUTE(packed) || (defined(__GNUC__) && !defined(__clang__)) #define ABSL_ATTRIBUTE_PACKED __attribute__((__packed__)) #else @@ -448,15 +513,16 @@ #endif // ABSL_CONST_INIT -// A variable declaration annotated with the ABSL_CONST_INIT attribute will +// +// A variable declaration annotated with the `ABSL_CONST_INIT` attribute will // not compile (on supported platforms) unless the variable has a constant // initializer. This is useful for variables with static and thread storage // duration, because it guarantees that they will not suffer from the so-called // "static init order fiasco". // -// Sample usage: +// Example: // -// ABSL_CONST_INIT static MyType my_var = MakeMyType(...); +// ABSL_CONST_INIT static MyType my_var = MakeMyType(...); // // Note that this attribute is redundant if the variable is declared constexpr. #if ABSL_HAVE_CPP_ATTRIBUTE(clang::require_constant_initialization) diff --git a/absl/base/call_once.h b/absl/base/call_once.h index 478a41c1..5d823a11 100644 --- a/absl/base/call_once.h +++ b/absl/base/call_once.h @@ -25,6 +25,7 @@ #ifndef ABSL_BASE_CALL_ONCE_H_ #define ABSL_BASE_CALL_ONCE_H_ +#include <algorithm> #include <atomic> #include <cstdint> #include <type_traits> @@ -32,7 +33,10 @@ #include "absl/base/internal/invoke.h" #include "absl/base/internal/low_level_scheduling.h" #include "absl/base/internal/raw_logging.h" +#include "absl/base/internal/scheduling_mode.h" #include "absl/base/internal/spinlock_wait.h" +#include "absl/base/macros.h" +#include "absl/base/port.h" namespace absl { diff --git a/absl/base/call_once_test.cc b/absl/base/call_once_test.cc index de235432..cd58ee19 100644 --- a/absl/base/call_once_test.cc +++ b/absl/base/call_once_test.cc @@ -14,12 +14,12 @@ #include "absl/base/call_once.h" -#include <atomic> #include <thread> +#include <vector> +#include "gtest/gtest.h" #include "absl/base/thread_annotations.h" #include "absl/synchronization/mutex.h" -#include "gtest/gtest.h" namespace absl { namespace { diff --git a/absl/base/config_test.cc b/absl/base/config_test.cc index 578bb810..ab04b447 100644 --- a/absl/base/config_test.cc +++ b/absl/base/config_test.cc @@ -16,7 +16,6 @@ #include <cstdint> -#include "gmock/gmock.h" #include "gtest/gtest.h" namespace { diff --git a/absl/base/dynamic_annotations.h b/absl/base/dynamic_annotations.h index b9c015ba..3b6d6ef4 100644 --- a/absl/base/dynamic_annotations.h +++ b/absl/base/dynamic_annotations.h @@ -298,7 +298,7 @@ void AnnotateIgnoreWritesEnd(const char *file, int line); while still letting the compiler elide the functions from the final build. TODO(delesley) -- The exclusive lock here ignores writes as well, but - allows INGORE_READS_AND_WRITES to work properly. */ + allows IGNORE_READS_AND_WRITES to work properly. */ #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wunused-function" static inline void StaticAnnotateIgnoreReadsBegin(const char *file, int line) diff --git a/absl/base/internal/atomic_hook.h b/absl/base/internal/atomic_hook.h index 8eee367e..1f9a8102 100644 --- a/absl/base/internal/atomic_hook.h +++ b/absl/base/internal/atomic_hook.h @@ -16,8 +16,8 @@ #ifndef ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_ #define ABSL_BASE_INTERNAL_ATOMIC_HOOK_H_ -#include <cassert> #include <atomic> +#include <cassert> #include <utility> namespace absl { diff --git a/absl/base/internal/endian_test.cc b/absl/base/internal/endian_test.cc index 6812214e..f3ff4b39 100644 --- a/absl/base/internal/endian_test.cc +++ b/absl/base/internal/endian_test.cc @@ -16,13 +16,11 @@ #include <algorithm> #include <cstdint> -#include <cstdio> #include <limits> #include <random> #include <vector> #include "gtest/gtest.h" -#include "absl/base/casts.h" #include "absl/base/config.h" namespace absl { diff --git a/absl/base/internal/low_level_alloc.cc b/absl/base/internal/low_level_alloc.cc index c55201b3..08f89ea9 100644 --- a/absl/base/internal/low_level_alloc.cc +++ b/absl/base/internal/low_level_alloc.cc @@ -17,17 +17,19 @@ // This allocator is slow and wasteful of memory; // it should not be used when performance is key. -#include "absl/base/config.h" - #include "absl/base/internal/low_level_alloc.h" +#include "absl/base/config.h" +#include "absl/base/internal/scheduling_mode.h" +#include "absl/base/macros.h" +#include "absl/base/thread_annotations.h" + // LowLevelAlloc requires that the platform support low-level // allocation of virtual memory. Platforms lacking this cannot use // LowLevelAlloc. #ifndef ABSL_LOW_LEVEL_ALLOC_MISSING #ifndef _WIN32 -#include <pthread.h> #include <signal.h> #include <sys/mman.h> #include <unistd.h> @@ -38,8 +40,8 @@ #include <string.h> #include <algorithm> #include <atomic> -#include <cstddef> #include <cerrno> +#include <cstddef> #include <new> // for placement-new #include "absl/base/dynamic_annotations.h" diff --git a/absl/base/internal/low_level_alloc.h b/absl/base/internal/low_level_alloc.h index d6eb813f..f3e8aa57 100644 --- a/absl/base/internal/low_level_alloc.h +++ b/absl/base/internal/low_level_alloc.h @@ -24,8 +24,10 @@ // IWYU pragma: private, include "base/low_level_alloc.h" +#include <sys/types.h> #include <cstdint> +#include "absl/base/attributes.h" #include "absl/base/config.h" // LowLevelAlloc requires that the platform support low-level diff --git a/absl/base/internal/low_level_alloc_test.cc b/absl/base/internal/low_level_alloc_test.cc index 5f60c3d9..2935760d 100644 --- a/absl/base/internal/low_level_alloc_test.cc +++ b/absl/base/internal/low_level_alloc_test.cc @@ -14,10 +14,12 @@ #include "absl/base/internal/low_level_alloc.h" +#include <stdint.h> #include <stdio.h> #include <stdlib.h> #include <thread> // NOLINT(build/c++11) #include <unordered_map> +#include <utility> #include "absl/base/internal/malloc_hook.h" diff --git a/absl/base/internal/low_level_scheduling.h b/absl/base/internal/low_level_scheduling.h index b9501076..a01d1c03 100644 --- a/absl/base/internal/low_level_scheduling.h +++ b/absl/base/internal/low_level_scheduling.h @@ -30,8 +30,8 @@ extern "C" void __google_enable_rescheduling(bool disable_result); namespace absl { namespace base_internal { -class SpinLock; // To allow use of SchedulingGuard. class SchedulingHelper; // To allow use of SchedulingGuard. +class SpinLock; // To allow use of SchedulingGuard. // SchedulingGuard // Provides guard semantics that may be used to disable cooperative rescheduling diff --git a/absl/base/internal/malloc_extension.cc b/absl/base/internal/malloc_extension.cc index daf4bc32..3da981ce 100644 --- a/absl/base/internal/malloc_extension.cc +++ b/absl/base/internal/malloc_extension.cc @@ -15,15 +15,12 @@ #include "absl/base/internal/malloc_extension.h" #include <assert.h> -#include <stdint.h> -#include <stdio.h> #include <string.h> #include <atomic> #include <string> #include "absl/base/dynamic_annotations.h" #include "absl/base/internal/malloc_extension_c.h" -#include "absl/base/port.h" namespace absl { namespace base_internal { diff --git a/absl/base/internal/malloc_extension.h b/absl/base/internal/malloc_extension.h index dee4116b..46b767ff 100644 --- a/absl/base/internal/malloc_extension.h +++ b/absl/base/internal/malloc_extension.h @@ -25,14 +25,15 @@ #ifndef ABSL_BASE_INTERNAL_MALLOC_EXTENSION_H_ #define ABSL_BASE_INTERNAL_MALLOC_EXTENSION_H_ +#include <stddef.h> +#include <stdint.h> #include <atomic> #include <map> #include <memory> +#include <string> #include <vector> -#include <stddef.h> -#include <stdint.h> -#include <string> +#include "absl/base/attributes.h" #include "absl/base/macros.h" #include "absl/base/port.h" namespace absl { diff --git a/absl/base/internal/malloc_hook.cc b/absl/base/internal/malloc_hook.cc index d5d227a5..4f5a0bef 100644 --- a/absl/base/internal/malloc_hook.cc +++ b/absl/base/internal/malloc_hook.cc @@ -23,16 +23,17 @@ #undef mremap #endif +#include "absl/base/internal/malloc_hook.h" + +#include <algorithm> #include <cstddef> #include <cstdint> -#include <algorithm> #include "absl/base/call_once.h" -#include "absl/base/casts.h" -#include "absl/base/internal/malloc_hook.h" #include "absl/base/internal/malloc_hook_invoke.h" #include "absl/base/internal/raw_logging.h" #include "absl/base/internal/spinlock.h" +#include "absl/base/macros.h" // __THROW is defined in glibc systems. It means, counter-intuitively, // "This function will never throw an exception." It's an optional diff --git a/absl/base/internal/raw_logging.cc b/absl/base/internal/raw_logging.cc index d197d444..c0890614 100644 --- a/absl/base/internal/raw_logging.cc +++ b/absl/base/internal/raw_logging.cc @@ -12,8 +12,9 @@ // See the License for the specific language governing permissions and // limitations under the License. -#include <atomic> -#include <cassert> +#include "absl/base/internal/raw_logging.h" + +#include <stddef.h> #include <cstdarg> #include <cstdio> #include <cstdlib> @@ -22,8 +23,6 @@ #include "absl/base/config.h" #include "absl/base/internal/atomic_hook.h" #include "absl/base/internal/log_severity.h" -#include "absl/base/internal/raw_logging.h" -#include "absl/base/port.h" // We know how to perform low-level writes to stderr in POSIX and Windows. For // these platforms, we define the token ABSL_LOW_LEVEL_WRITE_SUPPORTED. @@ -38,6 +37,7 @@ #if defined(__linux__) || defined(__APPLE__) || defined(__Fuchsia__) || \ defined(__GENCLAVE__) #include <unistd.h> + #define ABSL_HAVE_POSIX_WRITE 1 #define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1 #else @@ -57,6 +57,7 @@ #ifdef _WIN32 #include <io.h> + #define ABSL_HAVE_RAW_IO 1 #define ABSL_LOW_LEVEL_WRITE_SUPPORTED 1 #else diff --git a/absl/base/internal/raw_logging.h b/absl/base/internal/raw_logging.h index 47cf4373..568d2afc 100644 --- a/absl/base/internal/raw_logging.h +++ b/absl/base/internal/raw_logging.h @@ -19,6 +19,7 @@ #ifndef ABSL_BASE_INTERNAL_RAW_LOGGING_H_ #define ABSL_BASE_INTERNAL_RAW_LOGGING_H_ +#include "absl/base/attributes.h" #include "absl/base/internal/log_severity.h" #include "absl/base/macros.h" #include "absl/base/port.h" diff --git a/absl/base/internal/spinlock.cc b/absl/base/internal/spinlock.cc index 6257bfce..517668dc 100644 --- a/absl/base/internal/spinlock.cc +++ b/absl/base/internal/spinlock.cc @@ -16,8 +16,8 @@ #include <algorithm> #include <atomic> +#include <limits> -#include "absl/base/casts.h" #include "absl/base/internal/atomic_hook.h" #include "absl/base/internal/cycleclock.h" #include "absl/base/internal/spinlock_wait.h" diff --git a/absl/base/internal/spinlock.h b/absl/base/internal/spinlock.h index fa64ba65..1f50d745 100644 --- a/absl/base/internal/spinlock.h +++ b/absl/base/internal/spinlock.h @@ -30,11 +30,17 @@ #ifndef ABSL_BASE_INTERNAL_SPINLOCK_H_ #define ABSL_BASE_INTERNAL_SPINLOCK_H_ +#include <stdint.h> +#include <sys/types.h> #include <atomic> +#include "absl/base/attributes.h" #include "absl/base/dynamic_annotations.h" #include "absl/base/internal/low_level_scheduling.h" +#include "absl/base/internal/raw_logging.h" +#include "absl/base/internal/scheduling_mode.h" #include "absl/base/internal/tsan_mutex_interface.h" +#include "absl/base/macros.h" #include "absl/base/port.h" #include "absl/base/thread_annotations.h" diff --git a/absl/base/internal/spinlock_wait.h b/absl/base/internal/spinlock_wait.h index 5432c1ce..6734cc9e 100644 --- a/absl/base/internal/spinlock_wait.h +++ b/absl/base/internal/spinlock_wait.h @@ -22,6 +22,7 @@ // places listing in //base:spinlock_wait_users. If you need to use it outside // of //base, please request permission to be added to that list. +#include <stdint.h> #include <atomic> #include "absl/base/internal/scheduling_mode.h" diff --git a/absl/base/internal/sysinfo.cc b/absl/base/internal/sysinfo.cc index 11863eab..6a4c0064 100644 --- a/absl/base/internal/sysinfo.cc +++ b/absl/base/internal/sysinfo.cc @@ -48,7 +48,6 @@ #include "absl/base/internal/raw_logging.h" #include "absl/base/internal/spinlock.h" #include "absl/base/internal/unscaledcycleclock.h" -#include "absl/base/thread_annotations.h" namespace absl { namespace base_internal { diff --git a/absl/base/internal/thread_identity_test.cc b/absl/base/internal/thread_identity_test.cc index a2b053d9..7695a091 100644 --- a/absl/base/internal/thread_identity_test.cc +++ b/absl/base/internal/thread_identity_test.cc @@ -19,6 +19,7 @@ #include "gtest/gtest.h" #include "absl/base/internal/spinlock.h" +#include "absl/base/macros.h" #include "absl/synchronization/internal/per_thread_sem.h" #include "absl/synchronization/mutex.h" diff --git a/absl/base/internal/unscaledcycleclock.h b/absl/base/internal/unscaledcycleclock.h index ddf6a5e5..049f1cac 100644 --- a/absl/base/internal/unscaledcycleclock.h +++ b/absl/base/internal/unscaledcycleclock.h @@ -91,6 +91,7 @@ class UnscaledCycleClockWrapperForGetCurrentTime; namespace base_internal { class CycleClock; class UnscaledCycleClockWrapperForInitializeFrequency; + class UnscaledCycleClock { private: UnscaledCycleClock() = delete; diff --git a/absl/base/invoke_test.cc b/absl/base/invoke_test.cc index 2bbfc477..466bf114 100644 --- a/absl/base/invoke_test.cc +++ b/absl/base/invoke_test.cc @@ -17,6 +17,7 @@ #include <functional> #include <memory> #include <string> +#include <utility> #include "gmock/gmock.h" #include "gtest/gtest.h" diff --git a/absl/base/spinlock_test_common.cc b/absl/base/spinlock_test_common.cc index b1212eaf..6918603c 100644 --- a/absl/base/spinlock_test_common.cc +++ b/absl/base/spinlock_test_common.cc @@ -24,8 +24,10 @@ #include "gtest/gtest.h" #include "absl/base/internal/low_level_scheduling.h" +#include "absl/base/internal/scheduling_mode.h" #include "absl/base/internal/spinlock.h" #include "absl/base/internal/sysinfo.h" +#include "absl/base/macros.h" #include "absl/synchronization/blocking_counter.h" #include "absl/synchronization/notification.h" diff --git a/absl/base/throw_delegate_test.cc b/absl/base/throw_delegate_test.cc index f9494452..0f15df04 100644 --- a/absl/base/throw_delegate_test.cc +++ b/absl/base/throw_delegate_test.cc @@ -18,7 +18,6 @@ #include <new> #include <stdexcept> -#include "gmock/gmock.h" #include "gtest/gtest.h" namespace { diff --git a/absl/numeric/int128.h b/absl/numeric/int128.h index 72be806a..e3ba2384 100644 --- a/absl/numeric/int128.h +++ b/absl/numeric/int128.h @@ -78,10 +78,7 @@ namespace absl { // uint64_t i = v // Error // uint64_t i = static_cast<uint64_t>(v) // OK // -// NOTE: the alignment requirement of `uint128` is due to change, so users -// should take care to avoid depending on the current 8 byte alignment. -// TODO(strel) Remove alignment note above once alignof(uint128) becomes 16. -class uint128 { +class alignas(16) uint128 { public: uint128() = default; diff --git a/absl/synchronization/BUILD.bazel b/absl/synchronization/BUILD.bazel index bddd2eca..7efc67e6 100644 --- a/absl/synchronization/BUILD.bazel +++ b/absl/synchronization/BUILD.bazel @@ -80,6 +80,18 @@ cc_library( ) cc_test( + name = "barrier_test", + size = "small", + srcs = ["barrier_test.cc"], + copts = ABSL_TEST_COPTS, + deps = [ + ":synchronization", + "//absl/time", + "@com_google_googletest//:gtest_main", + ], +) + +cc_test( name = "blocking_counter_test", size = "small", srcs = ["blocking_counter_test.cc"], diff --git a/absl/synchronization/barrier_test.cc b/absl/synchronization/barrier_test.cc new file mode 100644 index 00000000..d6cababd --- /dev/null +++ b/absl/synchronization/barrier_test.cc @@ -0,0 +1,75 @@ +// 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/synchronization/barrier.h" + +#include <thread> // NOLINT(build/c++11) +#include <vector> + +#include "gtest/gtest.h" +#include "absl/synchronization/mutex.h" +#include "absl/time/clock.h" + + +TEST(Barrier, SanityTest) { + constexpr int kNumThreads = 10; + absl::Barrier* barrier = new absl::Barrier(kNumThreads); + + absl::Mutex mutex; + int counter = 0; // Guarded by mutex. + + auto thread_func = [&] { + if (barrier->Block()) { + // This thread is the last thread to reach the barrier so it is + // responsible for deleting it. + delete barrier; + } + + // Increment the counter. + absl::MutexLock lock(&mutex); + ++counter; + }; + + // Start (kNumThreads - 1) threads running thread_func. + std::vector<std::thread> threads; + for (int i = 0; i < kNumThreads - 1; ++i) { + threads.push_back(std::thread(thread_func)); + } + + // Give (kNumThreads - 1) threads a chance to reach the barrier. + // This test assumes at least one thread will have run after the + // sleep has elapsed. Sleeping in a test is usually bad form, but we + // need to make sure that we are testing the barrier instead of some + // other synchronization method. + absl::SleepFor(absl::Seconds(1)); + + // The counter should still be zero since no thread should have + // been able to pass the barrier yet. + { + absl::MutexLock lock(&mutex); + EXPECT_EQ(counter, 0); + } + + // Start 1 more thread. This should make all threads pass the barrier. + threads.push_back(std::thread(thread_func)); + + // All threads should now be able to proceed and finish. + for (auto& thread : threads) { + thread.join(); + } + + // All threads should now have incremented the counter. + absl::MutexLock lock(&mutex); + EXPECT_EQ(counter, kNumThreads); +} diff --git a/absl/time/duration_test.cc b/absl/time/duration_test.cc index eed96e3e..ec8e17f5 100644 --- a/absl/time/duration_test.cc +++ b/absl/time/duration_test.cc @@ -1527,4 +1527,5 @@ TEST(Duration, FormatParseRoundTrip) { #undef TEST_PARSE_ROUNDTRIP } + } // namespace diff --git a/absl/time/format_test.cc b/absl/time/format_test.cc index cd9a6f9d..b139ff6f 100644 --- a/absl/time/format_test.cc +++ b/absl/time/format_test.cc @@ -427,4 +427,5 @@ TEST(FormatParse, RoundTripDistantPast) { << s << ": " << err; EXPECT_EQ(in, out); } + } // namespace diff --git a/absl/types/optional.h b/absl/types/optional.h index 5099d489..3e010bd5 100644 --- a/absl/types/optional.h +++ b/absl/types/optional.h @@ -439,6 +439,33 @@ struct is_constructible_convertible_assignable_from_optional // for checking whether an expression is convertible to bool. bool convertible_to_bool(bool); +// Base class for std::hash<absl::optional<T>>: +// If std::hash<std::remove_const_t<T>> is enabled, it provides operator() to +// compute the hash; Otherwise, it is disabled. +// Reference N4659 23.14.15 [unord.hash]. +template <typename T, typename = size_t> +struct optional_hash_base { + optional_hash_base() = delete; + optional_hash_base(const optional_hash_base&) = delete; + optional_hash_base(optional_hash_base&&) = delete; + optional_hash_base& operator=(const optional_hash_base&) = delete; + optional_hash_base& operator=(optional_hash_base&&) = delete; +}; + +template <typename T> +struct optional_hash_base<T, decltype(std::hash<absl::remove_const_t<T> >()( + std::declval<absl::remove_const_t<T> >()))> { + using argument_type = absl::optional<T>; + using result_type = size_t; + size_t operator()(const absl::optional<T>& opt) const { + if (opt) { + return std::hash<absl::remove_const_t<T> >()(*opt); + } else { + return static_cast<size_t>(0x297814aaad196e6dULL); + } + } +}; + } // namespace optional_internal // ----------------------------------------------------------------------------- @@ -1072,15 +1099,8 @@ namespace std { // std::hash specialization for absl::optional. template <typename T> -struct hash<absl::optional<T>> { - size_t operator()(const absl::optional<T>& opt) const { - if (opt) { - return hash<T>()(*opt); - } else { - return static_cast<size_t>(0x297814aaad196e6dULL); - } - } -}; +struct hash<absl::optional<T> > + : absl::optional_internal::optional_hash_base<T> {}; } // namespace std diff --git a/absl/types/optional_test.cc b/absl/types/optional_test.cc index 25b44b17..65f43871 100644 --- a/absl/types/optional_test.cc +++ b/absl/types/optional_test.cc @@ -24,6 +24,17 @@ #include "absl/meta/type_traits.h" #include "absl/strings/string_view.h" +struct Hashable {}; + +namespace std { +template <> +struct hash<Hashable> { + size_t operator()(const Hashable&) { return 0; } +}; +} // namespace std + +struct NonHashable {}; + namespace { std::string TypeQuals(std::string&) { return "&"; } @@ -1434,6 +1445,17 @@ TEST(optionalTest, ValueType) { (std::is_same<absl::optional<int>::value_type, absl::nullopt_t>::value)); } +template <typename T> +struct is_hash_enabled_for { + template <typename U, typename = decltype(std::hash<U>()(std::declval<U>()))> + static std::true_type test(int); + + template <typename U> + static std::false_type test(...); + + static constexpr bool value = decltype(test<T>(0))::value; +}; + TEST(optionalTest, Hash) { std::hash<absl::optional<int>> hash; std::set<size_t> hashcodes; @@ -1442,6 +1464,34 @@ TEST(optionalTest, Hash) { hashcodes.insert(hash(i)); } EXPECT_GT(hashcodes.size(), 90); + + static_assert(is_hash_enabled_for<absl::optional<int>>::value, ""); + static_assert(is_hash_enabled_for<absl::optional<Hashable>>::value, ""); + +#if defined(_MSC_VER) || (defined(_LIBCPP_VERSION) && \ + _LIBCPP_VERSION < 4000 && _LIBCPP_STD_VER > 11) + // For MSVC and libc++ (< 4.0 and c++14), std::hash primary template has a + // static_assert to catch any user-defined type that doesn't provide a hash + // specialization. So instantiating std::hash<absl::optional<T>> will result + // in a hard error which is not SFINAE friendly. +#define ABSL_STD_HASH_NOT_SFINAE_FRIENDLY 1 +#endif + +#ifndef ABSL_STD_HASH_NOT_SFINAE_FRIENDLY + static_assert(!is_hash_enabled_for<absl::optional<NonHashable>>::value, ""); +#endif + + // libstdc++ std::optional is missing remove_const_t, i.e. it's using + // std::hash<T> rather than std::hash<std::remove_const_t<T>>. + // Reference: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82262 +#ifndef __GLIBCXX__ + static_assert(is_hash_enabled_for<absl::optional<const int>>::value, ""); + static_assert(is_hash_enabled_for<absl::optional<const Hashable>>::value, ""); + std::hash<absl::optional<const int>> c_hash; + for (int i = 0; i < 100; ++i) { + EXPECT_EQ(hash(i), c_hash(i)); + } +#endif } struct MoveMeNoThrow { diff --git a/absl/utility/utility.h b/absl/utility/utility.h index 4f4a0624..732cd4c5 100644 --- a/absl/utility/utility.h +++ b/absl/utility/utility.h @@ -12,36 +12,39 @@ // See the License for the specific language governing permissions and // limitations under the License. // - -// absl/utility:utility is an extension of the <utility> header +// This header file contains C++11 versions of standard <utility> header +// abstractions available within C++14 and C++17, and are designed to be drop-in +// replacement for code compliant with C++14 and C++17. +// +// The following abstractions are defined: // -// It provides stand-ins for C++14's std::integer_sequence and -// related utilities. They are intended to be exactly equivalent. -// - integer_sequence<T, Ints...> == std::integer_sequence<T, Ints...> -// - index_sequence<Ints...> == std::index_sequence<Ints...> -// - make_integer_sequence<T, N> == std::make_integer_sequence<T, N> -// - make_index_sequence<N> == std::make_index_sequence<N> -// - index_sequence_for<Ts...> == std::index_sequence_for<Ts...> +// * integer_sequence<T, Ints...> == std::integer_sequence<T, Ints...> +// * index_sequence<Ints...> == std::index_sequence<Ints...> +// * make_integer_sequence<T, N> == std::make_integer_sequence<T, N> +// * make_index_sequence<N> == std::make_index_sequence<N> +// * index_sequence_for<Ts...> == std::index_sequence_for<Ts...> // -// It also provides the tag types in_place_t, in_place_type_t, and -// in_place_index_t, as well as the constant in_place, and constexpr std::move -// and std::forward impolementations in C++11. +// This header file also provides the tag types `in_place_t`, `in_place_type_t`, +// and `in_place_index_t`, as well as the constant `in_place`, and +// `constexpr` `std::move()` and `std::forward()` implementations in C++11. // // References: +// // http://en.cppreference.com/w/cpp/utility/integer_sequence // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3658.html // +// // Example: // // Unpack a tuple for use as a function call's argument list. // // template <typename F, typename Tup, size_t... Is> -// auto Impl(F f, const Tup& tup, index_sequence<Is...>) +// auto Impl(F f, const Tup& tup, absl::index_sequence<Is...>) // -> decltype(f(std::get<Is>(tup) ...)) { // return f(std::get<Is>(tup) ...); // } // // template <typename Tup> -// using TupIdxSeq = make_index_sequence<std::tuple_size<Tup>::value>; +// using TupIdxSeq = absl::make_index_sequence<std::tuple_size<Tup>::value>; // // template <typename F, typename Tup> // auto ApplyFromTuple(F f, const Tup& tup) @@ -60,23 +63,36 @@ namespace absl { -// Equivalent to std::integer_sequence. +// integer_sequence +// +// Class template representing a compile-time integer sequence. An instantiation +// of `integer_sequence<T, Ints...>` has a sequence of integers encoded in its +// type through its template arguments (which is a common need when +// working with C++11 variadic templates). `absl::integer_sequence` is designed +// to be a drop-in replacement for C++14's `std::integer_sequence`. +// +// Example: // -// Function templates can deduce compile-time integer sequences by accepting -// an argument of integer_sequence<T, Ints...>. This is a common need when -// working with C++11 variadic templates. +// template< class T, T... Ints > +// void user_function(integer_sequence<T, Ints...>); // -// T - the integer type of the sequence elements -// ...Ints - a parameter pack of T values representing the sequence +// int main() +// { +// // user_function's `T` will be deduced to `int` and `Ints...` +// // will be deduced to `0, 1, 2, 3, 4`. +// user_function(make_integer_sequence<int, 5>()); +// } template <typename T, T... Ints> struct integer_sequence { using value_type = T; static constexpr size_t size() noexcept { return sizeof...(Ints); } }; -// Equivalent to std::index_sequence. +// index_sequence // -// Alias for an integer_sequence of size_t. +// A helper template for an `integer_sequence` of `size_t`, +// `absl::index_sequence` is designed to be a drop-in replacement for C++14's +// `std::index_sequence`. template <size_t... Ints> using index_sequence = integer_sequence<size_t, Ints...>; @@ -113,21 +129,27 @@ struct Gen<T, 0> { // Compile-time sequences of integers -// Equivalent to std::make_integer_sequence. +// make_integer_sequence // -// make_integer_sequence<int, N> is integer_sequence<int, 0, 1, ..., N-1>; +// This template alias is equivalent to +// `integer_sequence<int, 0, 1, ..., N-1>`, and is designed to be a drop-in +// replacement for C++14's `std::make_integer_sequence`. template <typename T, T N> using make_integer_sequence = typename utility_internal::Gen<T, N>::type; -// Equivalent to std::make_index_sequence. +// make_index_sequence // -// make_index_sequence<N> is index_sequence<0, 1, ..., N-1>; +// This template alias is equivalent to `index_sequence<0, 1, ..., N-1>`, +// and is designed to be a drop-in replacement for C++14's +// `std::make_index_sequence`. template <size_t N> using make_index_sequence = make_integer_sequence<size_t, N>; -// Equivalent to std::index_sequence_for. +// index_sequence_for // -// Convert a typename pack into an index sequence of the same length. +// Converts a typename pack into an index sequence of the same length, and +// is designed to be a drop-in replacement for C++14's +// `std::index_sequence_for()` template <typename... Ts> using index_sequence_for = make_index_sequence<sizeof...(Ts)>; @@ -140,8 +162,11 @@ using std::in_place; #else // ABSL_HAVE_STD_OPTIONAL -// Tag type used in order to specify in-place construction, such as with -// absl::optional. +// in_place_t +// +// Tag type used to specify in-place construction, such as with +// `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; @@ -150,22 +175,39 @@ extern const in_place_t in_place; #ifdef ABSL_HAVE_STD_ANY using std::in_place_type_t; #else -// Tag types used for in-place construction when the type to construct needs to -// be specified, such as with absl::variant and absl::any. + +// in_place_type_t +// +// Tag type used for in-place construction when the type to construct needs to +// be specified, such as with `absl::any`, designed to be a drop-in replacement +// for C++17's `std::in_place_type_t`. template <typename T> struct in_place_type_t {}; #endif // ABSL_HAVE_STD_ANY +// in_place_index_t +// +// Tag type used for in-place construction when the type to construct needs to +// be specified, such as with `absl::any`, designed to be a drop-in replacement +// for C++17's `std::in_place_index_t`. template <size_t I> struct in_place_index_t {}; // Constexpr move and forward +// move() +// +// A constexpr version of `std::move()`, designed to be a drop-in replacement +// for C++14's `std::move()`. template <typename T> constexpr absl::remove_reference_t<T>&& move(T&& t) noexcept { return static_cast<absl::remove_reference_t<T>&&>(t); } +// forward() +// +// A constexpr version of `std::forward()`, designed to be a drop-in replacement +// for C++14's `std::forward()`. template <typename T> constexpr T&& forward( absl::remove_reference_t<T>& t) noexcept { // NOLINT(runtime/references) |