diff options
22 files changed, 407 insertions, 126 deletions
diff --git a/CMake/AbseilDll.cmake b/CMake/AbseilDll.cmake index 3c0f6901..40219207 100644 --- a/CMake/AbseilDll.cmake +++ b/CMake/AbseilDll.cmake @@ -789,7 +789,7 @@ Cflags: -I\${includedir}${PC_CFLAGS}\n") # Abseil libraries require C++14 as the current minimum standard. When # compiled with C++17 (either because it is the compiler's default or # explicitly requested), then Abseil requires C++17. - _absl_target_compile_features_if_available(${_NAME} PUBLIC ${ABSL_INTERNAL_CXX_STD_FEATURE}) + _absl_target_compile_features_if_available(${_dll} PUBLIC ${ABSL_INTERNAL_CXX_STD_FEATURE}) else() # Note: This is legacy (before CMake 3.8) behavior. Setting the # target-level CXX_STANDARD property to ABSL_CXX_STANDARD (which is @@ -799,8 +799,8 @@ Cflags: -I\${includedir}${PC_CFLAGS}\n") # CXX_STANDARD_REQUIRED does guard against the top-level CMake project # not having enabled CMAKE_CXX_STANDARD_REQUIRED (which prevents # "decaying" to an older standard if the requested one isn't available). - set_property(TARGET ${_NAME} PROPERTY CXX_STANDARD ${ABSL_CXX_STANDARD}) - set_property(TARGET ${_NAME} PROPERTY CXX_STANDARD_REQUIRED ON) + set_property(TARGET ${_dll} PROPERTY CXX_STANDARD ${ABSL_CXX_STANDARD}) + set_property(TARGET ${_dll} PROPERTY CXX_STANDARD_REQUIRED ON) endif() install(TARGETS ${_dll} EXPORT ${PROJECT_NAME}Targets diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h index 33e05736..bc33389b 100644 --- a/absl/container/internal/raw_hash_set.h +++ b/absl/container/internal/raw_hash_set.h @@ -179,6 +179,7 @@ #include <iterator> #include <limits> #include <memory> +#include <string> #include <tuple> #include <type_traits> #include <utility> @@ -1038,35 +1039,75 @@ size_t SelectBucketCountForIterRange(InputIter first, InputIter last, return 0; } -#define ABSL_INTERNAL_ASSERT_IS_FULL(ctrl, generation, generation_ptr, \ - operation) \ - do { \ - ABSL_HARDENING_ASSERT((ctrl != nullptr) && operation \ - " called on end() iterator."); \ - ABSL_HARDENING_ASSERT((ctrl != EmptyGroup()) && operation \ - " called on default-constructed iterator."); \ - if (SwisstableGenerationsEnabled() && generation != *generation_ptr) \ - ABSL_INTERNAL_LOG(FATAL, operation \ - " called on invalidated iterator. The table could " \ - "have rehashed since this iterator was initialized."); \ - ABSL_HARDENING_ASSERT( \ - (IsFull(*ctrl)) && operation \ - " called on invalid iterator. The element might have been erased or " \ - "the table might have rehashed."); \ - } while (0) +constexpr bool SwisstableDebugEnabled() { +#if defined(ABSL_SWISSTABLE_ENABLE_GENERATIONS) || \ + ABSL_OPTION_HARDENED == 1 || !defined(NDEBUG) + return true; +#else + return false; +#endif +} + +inline void AssertIsFull(const ctrl_t* ctrl, GenerationType generation, + const GenerationType* generation_ptr, + const char* operation) { + if (!SwisstableDebugEnabled()) return; + if (ctrl == nullptr) { + ABSL_INTERNAL_LOG(FATAL, + std::string(operation) + " called on end() iterator."); + } + if (ctrl == EmptyGroup()) { + ABSL_INTERNAL_LOG(FATAL, std::string(operation) + + " called on default-constructed iterator."); + } + if (SwisstableGenerationsEnabled()) { + if (generation != *generation_ptr) { + ABSL_INTERNAL_LOG(FATAL, + std::string(operation) + + " called on invalid iterator. The table could have " + "rehashed since this iterator was initialized."); + } + if (!IsFull(*ctrl)) { + ABSL_INTERNAL_LOG( + FATAL, + std::string(operation) + + " called on invalid iterator. The element was likely erased."); + } + } else { + if (!IsFull(*ctrl)) { + ABSL_INTERNAL_LOG( + FATAL, + std::string(operation) + + " called on invalid iterator. The element might have been erased " + "or the table might have rehashed. Consider running with " + "--config=asan to diagnose rehashing issues."); + } + } +} // Note that for comparisons, null/end iterators are valid. inline void AssertIsValidForComparison(const ctrl_t* ctrl, GenerationType generation, const GenerationType* generation_ptr) { - ABSL_HARDENING_ASSERT( - (ctrl == nullptr || ctrl == EmptyGroup() || IsFull(*ctrl)) && - "Invalid iterator comparison. The element might have " - "been erased or the table might have rehashed."); - if (SwisstableGenerationsEnabled() && generation != *generation_ptr) { - ABSL_INTERNAL_LOG(FATAL, - "Invalid iterator comparison. The table could have " - "rehashed since this iterator was initialized."); + if (!SwisstableDebugEnabled()) return; + const bool ctrl_is_valid_for_comparison = + ctrl == nullptr || ctrl == EmptyGroup() || IsFull(*ctrl); + if (SwisstableGenerationsEnabled()) { + if (generation != *generation_ptr) { + ABSL_INTERNAL_LOG(FATAL, + "Invalid iterator comparison. The table could have " + "rehashed since this iterator was initialized."); + } + if (!ctrl_is_valid_for_comparison) { + ABSL_INTERNAL_LOG( + FATAL, "Invalid iterator comparison. The element was likely erased."); + } + } else { + ABSL_HARDENING_ASSERT( + ctrl_is_valid_for_comparison && + "Invalid iterator comparison. The element might have been erased or " + "the table might have rehashed. Consider running with --config=asan to " + "diagnose rehashing issues."); } } @@ -1097,8 +1138,7 @@ inline void AssertSameContainer(const ctrl_t* ctrl_a, const ctrl_t* ctrl_b, const void* const& slot_b, const GenerationType* generation_ptr_a, const GenerationType* generation_ptr_b) { -#if defined(ABSL_SWISSTABLE_ENABLE_GENERATIONS) || \ - ABSL_OPTION_HARDENED == 1 || !defined(NDEBUG) + if (!SwisstableDebugEnabled()) return; const bool a_is_default = ctrl_a == EmptyGroup(); const bool b_is_default = ctrl_b == EmptyGroup(); if (a_is_default != b_is_default) { @@ -1108,9 +1148,9 @@ inline void AssertSameContainer(const ctrl_t* ctrl_a, const ctrl_t* ctrl_b, "with non-default-constructed iterator."); } if (a_is_default && b_is_default) return; -#endif - if (SwisstableGenerationsEnabled() && generation_ptr_a != generation_ptr_b) { + if (SwisstableGenerationsEnabled()) { + if (generation_ptr_a == generation_ptr_b) return; const bool a_is_empty = generation_ptr_a == EmptyGeneration(); const bool b_is_empty = generation_ptr_b == EmptyGeneration(); if (a_is_empty != b_is_empty) { @@ -1129,11 +1169,13 @@ inline void AssertSameContainer(const ctrl_t* ctrl_a, const ctrl_t* ctrl_b, ABSL_INTERNAL_LOG(FATAL, "Invalid iterator comparison. Comparing non-end() " "iterators from different hashtables."); + } else { + ABSL_HARDENING_ASSERT( + AreItersFromSameContainer(ctrl_a, ctrl_b, slot_a, slot_b) && + "Invalid iterator comparison. The iterators may be from different " + "containers or the container might have rehashed. Consider running " + "with --config=asan to diagnose rehashing issues."); } - ABSL_HARDENING_ASSERT( - AreItersFromSameContainer(ctrl_a, ctrl_b, slot_a, slot_b) && - "Invalid iterator comparison. The iterators may be from different " - "containers or the container might have rehashed."); } struct FindInfo { @@ -1471,22 +1513,19 @@ class raw_hash_set { // PRECONDITION: not an end() iterator. reference operator*() const { - ABSL_INTERNAL_ASSERT_IS_FULL(ctrl_, generation(), generation_ptr(), - "operator*()"); + AssertIsFull(ctrl_, generation(), generation_ptr(), "operator*()"); return PolicyTraits::element(slot_); } // PRECONDITION: not an end() iterator. pointer operator->() const { - ABSL_INTERNAL_ASSERT_IS_FULL(ctrl_, generation(), generation_ptr(), - "operator->"); + AssertIsFull(ctrl_, generation(), generation_ptr(), "operator->"); return &operator*(); } // PRECONDITION: not an end() iterator. iterator& operator++() { - ABSL_INTERNAL_ASSERT_IS_FULL(ctrl_, generation(), generation_ptr(), - "operator++"); + AssertIsFull(ctrl_, generation(), generation_ptr(), "operator++"); ++ctrl_; ++slot_; skip_empty_or_deleted(); @@ -2052,8 +2091,7 @@ class raw_hash_set { // This overload is necessary because otherwise erase<K>(const K&) would be // a better match if non-const iterator is passed as an argument. void erase(iterator it) { - ABSL_INTERNAL_ASSERT_IS_FULL(it.ctrl_, it.generation(), it.generation_ptr(), - "erase()"); + AssertIsFull(it.ctrl_, it.generation(), it.generation_ptr(), "erase()"); PolicyTraits::destroy(&alloc_ref(), it.slot_); erase_meta_only(it); } @@ -2087,9 +2125,8 @@ class raw_hash_set { } node_type extract(const_iterator position) { - ABSL_INTERNAL_ASSERT_IS_FULL(position.inner_.ctrl_, - position.inner_.generation(), - position.inner_.generation_ptr(), "extract()"); + AssertIsFull(position.inner_.ctrl_, position.inner_.generation(), + position.inner_.generation_ptr(), "extract()"); auto node = CommonAccess::Transfer<node_type>(alloc_ref(), position.inner_.slot_); erase_meta_only(position); @@ -2739,6 +2776,5 @@ ABSL_NAMESPACE_END } // namespace absl #undef ABSL_SWISSTABLE_ENABLE_GENERATIONS -#undef ABSL_INTERNAL_ASSERT_IS_FULL #endif // ABSL_CONTAINER_INTERNAL_RAW_HASH_SET_H_ diff --git a/absl/container/internal/raw_hash_set_test.cc b/absl/container/internal/raw_hash_set_test.cc index 4f2d006d..c13b6757 100644 --- a/absl/container/internal/raw_hash_set_test.cc +++ b/absl/container/internal/raw_hash_set_test.cc @@ -2056,7 +2056,8 @@ bool IsAssertEnabled() { } TEST(TableDeathTest, InvalidIteratorAsserts) { - if (!IsAssertEnabled()) GTEST_SKIP() << "Assertions not enabled."; + if (!IsAssertEnabled() && !SwisstableGenerationsEnabled()) + GTEST_SKIP() << "Assertions not enabled."; IntTable t; // Extra simple "regexp" as regexp support is highly varied across platforms. @@ -2068,9 +2069,12 @@ TEST(TableDeathTest, InvalidIteratorAsserts) { t.insert(0); iter = t.begin(); t.erase(iter); - EXPECT_DEATH_IF_SUPPORTED(++iter, - "operator.* called on invalid iterator. The " - "element might have been erased"); + const char* const kErasedDeathMessage = + SwisstableGenerationsEnabled() + ? "operator.* called on invalid iterator.*was likely erased" + : "operator.* called on invalid iterator.*might have been " + "erased.*config=asan"; + EXPECT_DEATH_IF_SUPPORTED(++iter, kErasedDeathMessage); } // Invalid iterator use can trigger heap-use-after-free in asan, @@ -2087,7 +2091,8 @@ constexpr bool kMsvc = false; #endif TEST(TableDeathTest, IteratorInvalidAssertsEqualityOperator) { - if (!IsAssertEnabled()) GTEST_SKIP() << "Assertions not enabled."; + if (!IsAssertEnabled() && !SwisstableGenerationsEnabled()) + GTEST_SKIP() << "Assertions not enabled."; IntTable t; t.insert(1); @@ -2100,8 +2105,9 @@ TEST(TableDeathTest, IteratorInvalidAssertsEqualityOperator) { t.erase(iter1); // Extra simple "regexp" as regexp support is highly varied across platforms. const char* const kErasedDeathMessage = - "Invalid iterator comparison. The element might have .*been erased or " - "the table might have rehashed."; + SwisstableGenerationsEnabled() + ? "Invalid iterator comparison.*was likely erased" + : "Invalid iterator comparison.*might have been erased.*config=asan"; EXPECT_DEATH_IF_SUPPORTED(void(iter1 == iter2), kErasedDeathMessage); EXPECT_DEATH_IF_SUPPORTED(void(iter2 != iter1), kErasedDeathMessage); t.erase(iter2); @@ -2114,17 +2120,20 @@ TEST(TableDeathTest, IteratorInvalidAssertsEqualityOperator) { iter2 = t2.begin(); const char* const kContainerDiffDeathMessage = SwisstableGenerationsEnabled() - ? "Invalid iterator comparison.*non-end" - : "Invalid iterator comparison. The iterators may be from different " - ".*containers or the container might have rehashed."; + ? "Invalid iterator comparison.*iterators from different hashtables" + : "Invalid iterator comparison.*may be from different " + ".*containers.*config=asan"; EXPECT_DEATH_IF_SUPPORTED(void(iter1 == iter2), kContainerDiffDeathMessage); EXPECT_DEATH_IF_SUPPORTED(void(iter2 == iter1), kContainerDiffDeathMessage); for (int i = 0; i < 10; ++i) t1.insert(i); // There should have been a rehash in t1. if (kMsvc) return; // MSVC doesn't support | in regex. - EXPECT_DEATH_IF_SUPPORTED(void(iter1 == t1.begin()), - kInvalidIteratorDeathMessage); + const char* const kRehashedDeathMessage = + SwisstableGenerationsEnabled() + ? kInvalidIteratorDeathMessage + : "Invalid iterator comparison.*might have rehashed.*config=asan"; + EXPECT_DEATH_IF_SUPPORTED(void(iter1 == t1.begin()), kRehashedDeathMessage); } #if defined(ABSL_INTERNAL_HASHTABLEZ_SAMPLE) diff --git a/absl/crc/internal/crc_cord_state.cc b/absl/crc/internal/crc_cord_state.cc index d0be0ddd..28d04dc4 100644 --- a/absl/crc/internal/crc_cord_state.cc +++ b/absl/crc/internal/crc_cord_state.cc @@ -121,7 +121,7 @@ void CrcCordState::Poison() { } } else { // Add a fake corrupt chunk. - rep->prefix_crc.push_back(PrefixCrc(0, crc32c_t{1})); + rep->prefix_crc.emplace_back(0, crc32c_t{1}); } } diff --git a/absl/crc/internal/crc_internal.h b/absl/crc/internal/crc_internal.h index 0611b383..9f080913 100644 --- a/absl/crc/internal/crc_internal.h +++ b/absl/crc/internal/crc_internal.h @@ -64,7 +64,7 @@ class CRCImpl : public CRC { // Implemention of the abstract class CRC public: using Uint32By256 = uint32_t[256]; - CRCImpl() {} + CRCImpl() = default; ~CRCImpl() override = default; // The internal version of CRC::New(). @@ -96,8 +96,8 @@ class CRCImpl : public CRC { // Implemention of the abstract class CRC // This is the 32-bit implementation. It handles all sizes from 8 to 32. class CRC32 : public CRCImpl { public: - CRC32() {} - ~CRC32() override {} + CRC32() = default; + ~CRC32() override = default; void Extend(uint32_t* crc, const void* bytes, size_t length) const override; void ExtendByZeroes(uint32_t* crc, size_t length) const override; diff --git a/absl/debugging/leak_check.cc b/absl/debugging/leak_check.cc index 195e82bf..fdb8798b 100644 --- a/absl/debugging/leak_check.cc +++ b/absl/debugging/leak_check.cc @@ -65,8 +65,8 @@ bool LeakCheckerIsActive() { return false; } void DoIgnoreLeak(const void*) { } void RegisterLivePointers(const void*, size_t) { } void UnRegisterLivePointers(const void*, size_t) { } -LeakCheckDisabler::LeakCheckDisabler() { } -LeakCheckDisabler::~LeakCheckDisabler() { } +LeakCheckDisabler::LeakCheckDisabler() = default; +LeakCheckDisabler::~LeakCheckDisabler() = default; ABSL_NAMESPACE_END } // namespace absl diff --git a/absl/debugging/symbolize_elf.inc b/absl/debugging/symbolize_elf.inc index ffb4eecf..0fee89f2 100644 --- a/absl/debugging/symbolize_elf.inc +++ b/absl/debugging/symbolize_elf.inc @@ -532,6 +532,11 @@ bool ForEachSection(int fd, return false; } + // Technically it can be larger, but in practice this never happens. + if (elf_header.e_shentsize != sizeof(ElfW(Shdr))) { + return false; + } + ElfW(Shdr) shstrtab; off_t shstrtab_offset = static_cast<off_t>(elf_header.e_shoff) + elf_header.e_shentsize * elf_header.e_shstrndx; @@ -584,6 +589,11 @@ bool GetSectionHeaderByName(int fd, const char *name, size_t name_len, return false; } + // Technically it can be larger, but in practice this never happens. + if (elf_header.e_shentsize != sizeof(ElfW(Shdr))) { + return false; + } + ElfW(Shdr) shstrtab; off_t shstrtab_offset = static_cast<off_t>(elf_header.e_shoff) + elf_header.e_shentsize * elf_header.e_shstrndx; diff --git a/absl/flags/internal/commandlineflag.cc b/absl/flags/internal/commandlineflag.cc index 4482955c..3c114d10 100644 --- a/absl/flags/internal/commandlineflag.cc +++ b/absl/flags/internal/commandlineflag.cc @@ -19,7 +19,7 @@ namespace absl { ABSL_NAMESPACE_BEGIN namespace flags_internal { -FlagStateInterface::~FlagStateInterface() {} +FlagStateInterface::~FlagStateInterface() = default; } // namespace flags_internal ABSL_NAMESPACE_END diff --git a/absl/flags/internal/usage.cc b/absl/flags/internal/usage.cc index 5efc7b07..e9481488 100644 --- a/absl/flags/internal/usage.cc +++ b/absl/flags/internal/usage.cc @@ -130,7 +130,7 @@ class FlagHelpPrettyPrinter { for (auto line : absl::StrSplit(str, absl::ByAnyChar("\n\r"))) { if (!tokens.empty()) { // Keep line separators in the input string. - tokens.push_back("\n"); + tokens.emplace_back("\n"); } for (auto token : absl::StrSplit(line, absl::ByAnyChar(" \t"), absl::SkipEmpty())) { diff --git a/absl/flags/parse.cc b/absl/flags/parse.cc index fa953f55..368248e3 100644 --- a/absl/flags/parse.cc +++ b/absl/flags/parse.cc @@ -190,7 +190,7 @@ bool ArgsList::ReadFromFlagfile(const std::string& flag_file_name) { // This argument represents fake argv[0], which should be present in all arg // lists. - args_.push_back(""); + args_.emplace_back(""); std::string line; bool success = true; @@ -212,7 +212,7 @@ bool ArgsList::ReadFromFlagfile(const std::string& flag_file_name) { break; } - args_.push_back(std::string(stripped)); + args_.emplace_back(stripped); continue; } @@ -367,7 +367,7 @@ bool ReadFlagsFromEnv(const std::vector<std::string>& flag_names, // This argument represents fake argv[0], which should be present in all arg // lists. - args.push_back(""); + args.emplace_back(""); for (const auto& flag_name : flag_names) { // Avoid infinite recursion. @@ -680,7 +680,7 @@ std::vector<char*> ParseCommandLineImpl(int argc, char* argv[], std::vector<std::string> flagfile_value; std::vector<ArgsList> input_args; - input_args.push_back(ArgsList(argc, argv)); + input_args.emplace_back(argc, argv); std::vector<char*> output_args; std::vector<char*> positional_args; diff --git a/absl/functional/any_invocable_test.cc b/absl/functional/any_invocable_test.cc index 1ed85407..10a4dee5 100644 --- a/absl/functional/any_invocable_test.cc +++ b/absl/functional/any_invocable_test.cc @@ -1431,14 +1431,14 @@ TYPED_TEST_P(AnyInvTestRvalue, QualifierIndependentObjectLifetime) { auto refs = std::make_shared<std::nullptr_t>(); { AnyInvType fun([refs](auto&&...) noexcept { return 0; }); - EXPECT_FALSE(refs.unique()); + EXPECT_GT(refs.use_count(), 1); std::move(fun)(7, 8, 9); // Ensure destructor hasn't run even if rref-qualified - EXPECT_FALSE(refs.unique()); + EXPECT_GT(refs.use_count(), 1); } - EXPECT_TRUE(refs.unique()); + EXPECT_EQ(refs.use_count(), 1); } // NOTE: This test suite originally attempted to enumerate all possible diff --git a/absl/hash/internal/hash.h b/absl/hash/internal/hash.h index b1452c4c..61970e0d 100644 --- a/absl/hash/internal/hash.h +++ b/absl/hash/internal/hash.h @@ -1074,6 +1074,7 @@ class ABSL_DLL MixingHashState : public HashStateBase<MixingHashState> { // Reads 1 to 3 bytes from p. Zero pads to fill uint32_t. static uint32_t Read1To3(const unsigned char* p, size_t len) { + // The trick used by this implementation is to avoid branches if possible. unsigned char mem0 = p[0]; unsigned char mem1 = p[len / 2]; unsigned char mem2 = p[len - 1]; @@ -1136,7 +1137,8 @@ class ABSL_DLL MixingHashState : public HashStateBase<MixingHashState> { // probably per-build and not per-process. ABSL_ATTRIBUTE_ALWAYS_INLINE static uint64_t Seed() { #if (!defined(__clang__) || __clang_major__ > 11) && \ - !defined(__apple_build_version__) + (!defined(__apple_build_version__) || \ + __apple_build_version__ >= 19558921) // Xcode 12 return static_cast<uint64_t>(reinterpret_cast<uintptr_t>(&kSeed)); #else // Workaround the absence of diff --git a/absl/log/internal/nullstream.h b/absl/log/internal/nullstream.h index 8ed63d52..16f5f495 100644 --- a/absl/log/internal/nullstream.h +++ b/absl/log/internal/nullstream.h @@ -114,7 +114,7 @@ class NullStreamMaybeFatal final : public NullStream { // and expression-defined severity use `NullStreamMaybeFatal` above. class NullStreamFatal final : public NullStream { public: - NullStreamFatal() {} + NullStreamFatal() = default; // ABSL_ATTRIBUTE_NORETURN doesn't seem to work on destructors with msvc, so // disable msvc's warning about the d'tor never returning. #if defined(_MSC_VER) && !defined(__clang__) diff --git a/absl/synchronization/internal/futex.h b/absl/synchronization/internal/futex.h index 9cf9841d..62bb40f7 100644 --- a/absl/synchronization/internal/futex.h +++ b/absl/synchronization/internal/futex.h @@ -16,9 +16,7 @@ #include "absl/base/config.h" -#ifdef _WIN32 -#include <windows.h> -#else +#ifndef _WIN32 #include <sys/time.h> #include <unistd.h> #endif @@ -85,34 +83,60 @@ namespace synchronization_internal { class FutexImpl { public: - static int WaitUntil(std::atomic<int32_t> *v, int32_t val, + // Atomically check that `*v == val`, and if it is, then sleep until the + // timeout `t` has been reached, or until woken by `Wake()`. + static int WaitUntil(std::atomic<int32_t>* v, int32_t val, KernelTimeout t) { - long err = 0; // NOLINT(runtime/int) - if (t.has_timeout()) { - // https://locklessinc.com/articles/futex_cheat_sheet/ - // Unlike FUTEX_WAIT, FUTEX_WAIT_BITSET uses absolute time. - struct timespec abs_timeout = t.MakeAbsTimespec(); - // Atomically check that the futex value is still 0, and if it - // is, sleep until abs_timeout or until woken by FUTEX_WAKE. - err = syscall( - SYS_futex, reinterpret_cast<int32_t *>(v), - FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME, val, - &abs_timeout, nullptr, FUTEX_BITSET_MATCH_ANY); + if (!t.has_timeout()) { + return Wait(v, val); + } else if (t.is_absolute_timeout()) { + auto abs_timespec = t.MakeAbsTimespec(); + return WaitAbsoluteTimeout(v, val, &abs_timespec); } else { - // Atomically check that the futex value is still 0, and if it - // is, sleep until woken by FUTEX_WAKE. - err = syscall(SYS_futex, reinterpret_cast<int32_t *>(v), - FUTEX_WAIT | FUTEX_PRIVATE_FLAG, val, nullptr); + auto rel_timespec = t.MakeRelativeTimespec(); + return WaitRelativeTimeout(v, val, &rel_timespec); } - if (ABSL_PREDICT_FALSE(err != 0)) { + } + + // Atomically check that `*v == val`, and if it is, then sleep until the until + // woken by `Wake()`. + static int Wait(std::atomic<int32_t>* v, int32_t val) { + return WaitAbsoluteTimeout(v, val, nullptr); + } + + // Atomically check that `*v == val`, and if it is, then sleep until + // CLOCK_REALTIME reaches `*abs_timeout`, or until woken by `Wake()`. + static int WaitAbsoluteTimeout(std::atomic<int32_t>* v, int32_t val, + const struct timespec* abs_timeout) { + // https://locklessinc.com/articles/futex_cheat_sheet/ + // Unlike FUTEX_WAIT, FUTEX_WAIT_BITSET uses absolute time. + auto err = + syscall(SYS_futex, reinterpret_cast<int32_t*>(v), + FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME, + val, abs_timeout, nullptr, FUTEX_BITSET_MATCH_ANY); + if (err != 0) { + return -errno; + } + return 0; + } + + // Atomically check that `*v == val`, and if it is, then sleep until + // `*rel_timeout` has elapsed, or until woken by `Wake()`. + static int WaitRelativeTimeout(std::atomic<int32_t>* v, int32_t val, + const struct timespec* rel_timeout) { + // Atomically check that the futex value is still 0, and if it + // is, sleep until abs_timeout or until woken by FUTEX_WAKE. + auto err = syscall(SYS_futex, reinterpret_cast<int32_t*>(v), + FUTEX_PRIVATE_FLAG, val, rel_timeout); + if (err != 0) { return -errno; } return 0; } - static int Wake(std::atomic<int32_t> *v, int32_t count) { - // NOLINTNEXTLINE(runtime/int) - long err = syscall(SYS_futex, reinterpret_cast<int32_t*>(v), + // Wakes at most `count` waiters that have entered the sleep state on `v`. + static int Wake(std::atomic<int32_t>* v, int32_t count) { + auto err = syscall(SYS_futex, reinterpret_cast<int32_t*>(v), FUTEX_WAKE | FUTEX_PRIVATE_FLAG, count); if (ABSL_PREDICT_FALSE(err < 0)) { return -errno; diff --git a/absl/synchronization/internal/kernel_timeout.cc b/absl/synchronization/internal/kernel_timeout.cc index 8d9e7d74..548a8fc6 100644 --- a/absl/synchronization/internal/kernel_timeout.cc +++ b/absl/synchronization/internal/kernel_timeout.cc @@ -15,6 +15,7 @@ #include "absl/synchronization/internal/kernel_timeout.h" #include <algorithm> +#include <chrono> // NOLINT(build/c++11) #include <cstdint> #include <ctime> #include <limits> @@ -163,6 +164,46 @@ KernelTimeout::DWord KernelTimeout::InMillisecondsFromNow() const { return DWord{0}; } +std::chrono::time_point<std::chrono::system_clock> +KernelTimeout::ToChronoTimePoint() const { + if (!has_timeout()) { + return std::chrono::time_point<std::chrono::system_clock>::max(); + } + + // The cast to std::microseconds is because (on some platforms) the + // std::ratio used by std::chrono::steady_clock doesn't convert to + // std::nanoseconds, so it doesn't compile. + auto micros = std::chrono::duration_cast<std::chrono::microseconds>( + std::chrono::nanoseconds(RawNanos())); + if (is_relative_timeout()) { + auto now = std::chrono::system_clock::now(); + if (micros > + std::chrono::time_point<std::chrono::system_clock>::max() - now) { + // Overflow. + return std::chrono::time_point<std::chrono::system_clock>::max(); + } + return now + micros; + } + return std::chrono::system_clock::from_time_t(0) + micros; +} + +std::chrono::nanoseconds KernelTimeout::ToChronoDuration() const { + if (!has_timeout()) { + return std::chrono::nanoseconds::max(); + } + if (is_absolute_timeout()) { + auto d = std::chrono::duration_cast<std::chrono::nanoseconds>( + std::chrono::nanoseconds(RawNanos()) - + (std::chrono::system_clock::now() - + std::chrono::system_clock::from_time_t(0))); + if (d < std::chrono::nanoseconds(0)) { + d = std::chrono::nanoseconds(0); + } + return d; + } + return std::chrono::nanoseconds(RawNanos()); +} + } // namespace synchronization_internal ABSL_NAMESPACE_END } // namespace absl diff --git a/absl/synchronization/internal/kernel_timeout.h b/absl/synchronization/internal/kernel_timeout.h index 1f4d82cd..f7c40337 100644 --- a/absl/synchronization/internal/kernel_timeout.h +++ b/absl/synchronization/internal/kernel_timeout.h @@ -16,6 +16,7 @@ #define ABSL_SYNCHRONIZATION_INTERNAL_KERNEL_TIMEOUT_H_ #include <algorithm> +#include <chrono> // NOLINT(build/c++11) #include <cstdint> #include <ctime> #include <limits> @@ -95,6 +96,20 @@ class KernelTimeout { typedef unsigned long DWord; // NOLINT DWord InMillisecondsFromNow() const; + // Convert to std::chrono::time_point for interfaces that expect an absolute + // timeout, like std::condition_variable::wait_until(). If !has_timeout() or + // is_relative_timeout(), attempts to convert to a reasonable absolute + // timeout, but callers should test has_timeout() and is_relative_timeout() + // and prefer to use a more appropriate interface. + std::chrono::time_point<std::chrono::system_clock> ToChronoTimePoint() const; + + // Convert to std::chrono::time_point for interfaces that expect a relative + // timeout, like std::condition_variable::wait_for(). If !has_timeout() or + // is_absolute_timeout(), attempts to convert to a reasonable relative + // timeout, but callers should test has_timeout() and is_absolute_timeout() + // and prefer to use a more appropriate interface. + std::chrono::nanoseconds ToChronoDuration() const; + private: // Internal representation. // - If the value is kNoTimeout, then the timeout is infinite, and diff --git a/absl/synchronization/internal/kernel_timeout_test.cc b/absl/synchronization/internal/kernel_timeout_test.cc index a89ae220..431ffcf4 100644 --- a/absl/synchronization/internal/kernel_timeout_test.cc +++ b/absl/synchronization/internal/kernel_timeout_test.cc @@ -14,6 +14,7 @@ #include "absl/synchronization/internal/kernel_timeout.h" +#include <chrono> // NOLINT(build/c++11) #include <limits> #include "gtest/gtest.h" @@ -72,6 +73,11 @@ TEST(KernelTimeout, FiniteTimes) { EXPECT_LE(absl::AbsDuration(absl::Milliseconds(t.InMillisecondsFromNow()) - std::max(duration, absl::ZeroDuration())), absl::Milliseconds(5)); + EXPECT_LE(absl::AbsDuration(absl::FromChrono(t.ToChronoTimePoint()) - when), + absl::Microseconds(1)); + EXPECT_LE(absl::AbsDuration(absl::FromChrono(t.ToChronoDuration()) - + std::max(duration, absl::ZeroDuration())), + kTimingBound); } } @@ -90,6 +96,9 @@ TEST(KernelTimeout, InfiniteFuture) { absl::Now() + absl::Hours(100000)); EXPECT_EQ(t.InMillisecondsFromNow(), std::numeric_limits<KernelTimeout::DWord>::max()); + EXPECT_EQ(t.ToChronoTimePoint(), + std::chrono::time_point<std::chrono::system_clock>::max()); + EXPECT_GE(t.ToChronoDuration(), std::chrono::nanoseconds::max()); } TEST(KernelTimeout, DefaultConstructor) { @@ -108,6 +117,9 @@ TEST(KernelTimeout, DefaultConstructor) { absl::Now() + absl::Hours(100000)); EXPECT_EQ(t.InMillisecondsFromNow(), std::numeric_limits<KernelTimeout::DWord>::max()); + EXPECT_EQ(t.ToChronoTimePoint(), + std::chrono::time_point<std::chrono::system_clock>::max()); + EXPECT_GE(t.ToChronoDuration(), std::chrono::nanoseconds::max()); } TEST(KernelTimeout, TimeMaxNanos) { @@ -126,6 +138,9 @@ TEST(KernelTimeout, TimeMaxNanos) { absl::Now() + absl::Hours(100000)); EXPECT_EQ(t.InMillisecondsFromNow(), std::numeric_limits<KernelTimeout::DWord>::max()); + EXPECT_EQ(t.ToChronoTimePoint(), + std::chrono::time_point<std::chrono::system_clock>::max()); + EXPECT_GE(t.ToChronoDuration(), std::chrono::nanoseconds::max()); } TEST(KernelTimeout, Never) { @@ -144,6 +159,9 @@ TEST(KernelTimeout, Never) { absl::Now() + absl::Hours(100000)); EXPECT_EQ(t.InMillisecondsFromNow(), std::numeric_limits<KernelTimeout::DWord>::max()); + EXPECT_EQ(t.ToChronoTimePoint(), + std::chrono::time_point<std::chrono::system_clock>::max()); + EXPECT_GE(t.ToChronoDuration(), std::chrono::nanoseconds::max()); } TEST(KernelTimeout, InfinitePast) { @@ -157,6 +175,9 @@ TEST(KernelTimeout, InfinitePast) { absl::ZeroDuration()); EXPECT_LE(absl::FromUnixNanos(t.MakeAbsNanos()), absl::FromUnixNanos(1)); EXPECT_EQ(t.InMillisecondsFromNow(), KernelTimeout::DWord{0}); + EXPECT_LT(t.ToChronoTimePoint(), std::chrono::system_clock::from_time_t(0) + + std::chrono::seconds(1)); + EXPECT_EQ(t.ToChronoDuration(), std::chrono::nanoseconds(0)); } TEST(KernelTimeout, FiniteDurations) { @@ -186,6 +207,10 @@ TEST(KernelTimeout, FiniteDurations) { absl::Milliseconds(5)); EXPECT_LE(absl::Milliseconds(t.InMillisecondsFromNow()) - duration, absl::Milliseconds(5)); + EXPECT_LE(absl::AbsDuration(absl::Now() + duration - + absl::FromChrono(t.ToChronoTimePoint())), + kTimingBound); + EXPECT_EQ(absl::FromChrono(t.ToChronoDuration()), duration); } } @@ -218,6 +243,10 @@ TEST(KernelTimeout, NegativeDurations) { absl::AbsDuration(absl::Now() - absl::FromUnixNanos(t.MakeAbsNanos())), absl::Milliseconds(5)); EXPECT_EQ(t.InMillisecondsFromNow(), KernelTimeout::DWord{0}); + EXPECT_LE(absl::AbsDuration(absl::Now() - + absl::FromChrono(t.ToChronoTimePoint())), + absl::Milliseconds(5)); + EXPECT_EQ(t.ToChronoDuration(), std::chrono::nanoseconds(0)); } } @@ -236,6 +265,9 @@ TEST(KernelTimeout, InfiniteDuration) { absl::Now() + absl::Hours(100000)); EXPECT_EQ(t.InMillisecondsFromNow(), std::numeric_limits<KernelTimeout::DWord>::max()); + EXPECT_EQ(t.ToChronoTimePoint(), + std::chrono::time_point<std::chrono::system_clock>::max()); + EXPECT_GE(t.ToChronoDuration(), std::chrono::nanoseconds::max()); } TEST(KernelTimeout, DurationMaxNanos) { @@ -254,6 +286,9 @@ TEST(KernelTimeout, DurationMaxNanos) { absl::Now() + absl::Hours(100000)); EXPECT_EQ(t.InMillisecondsFromNow(), std::numeric_limits<KernelTimeout::DWord>::max()); + EXPECT_EQ(t.ToChronoTimePoint(), + std::chrono::time_point<std::chrono::system_clock>::max()); + EXPECT_GE(t.ToChronoDuration(), std::chrono::nanoseconds::max()); } TEST(KernelTimeout, OverflowNanos) { @@ -273,6 +308,9 @@ TEST(KernelTimeout, OverflowNanos) { absl::Now() + absl::Hours(100000)); EXPECT_LE(absl::Milliseconds(t.InMillisecondsFromNow()) - duration, absl::Milliseconds(5)); + EXPECT_GT(t.ToChronoTimePoint(), + std::chrono::system_clock::now() + std::chrono::hours(100000)); + EXPECT_GT(t.ToChronoDuration(), std::chrono::hours(100000)); } } // namespace diff --git a/absl/synchronization/internal/waiter.cc b/absl/synchronization/internal/waiter.cc index f2051d67..4eee1298 100644 --- a/absl/synchronization/internal/waiter.cc +++ b/absl/synchronization/internal/waiter.cc @@ -67,11 +67,9 @@ static void MaybeBecomeIdle() { #if ABSL_WAITER_MODE == ABSL_WAITER_MODE_FUTEX -Waiter::Waiter() { - futex_.store(0, std::memory_order_relaxed); -} +Waiter::Waiter() : futex_(0) {} -bool Waiter::Wait(KernelTimeout t) { +bool Waiter::WaitAbsoluteTimeout(KernelTimeout t) { // Loop until we can atomically decrement futex from a positive // value, waiting on a futex while we believe it is zero. // Note that, since the thread ticker is just reset, we don't need to check @@ -90,7 +88,88 @@ bool Waiter::Wait(KernelTimeout t) { } if (!first_pass) MaybeBecomeIdle(); - const int err = Futex::WaitUntil(&futex_, 0, t); + auto abs_timeout = t.MakeAbsTimespec(); + const int err = Futex::WaitAbsoluteTimeout(&futex_, 0, &abs_timeout); + if (err != 0) { + if (err == -EINTR || err == -EWOULDBLOCK) { + // Do nothing, the loop will retry. + } else if (err == -ETIMEDOUT) { + return false; + } else { + ABSL_RAW_LOG(FATAL, "Futex operation failed with error %d\n", err); + } + } + first_pass = false; + } +} + +#ifdef CLOCK_MONOTONIC + +// Subtracts the timespec `sub` from `in` if the result would not be negative, +// and returns true. Returns false if the result would be negative, and leaves +// `in` unchanged. +static bool TimespecSubtract(struct timespec& in, const struct timespec& sub) { + if (in.tv_sec < sub.tv_sec) { + return false; + } + if (in.tv_nsec < sub.tv_nsec) { + if (in.tv_sec == sub.tv_sec) { + return false; + } + // Borrow from tv_sec. + in.tv_sec -= 1; + in.tv_nsec += 1'000'000'000; + } + in.tv_sec -= sub.tv_sec; + in.tv_nsec -= sub.tv_nsec; + return true; +} + +// On some platforms a background thread periodically calls `Poke()` to briefly +// wake waiter threads so that they may call `MaybeBecomeIdle()`. This means +// that `WaitRelativeTimeout()` differs slightly from `WaitAbsoluteTimeout()` +// because it must adjust the timeout by the amount of time that it has already +// slept. +bool Waiter::WaitRelativeTimeout(KernelTimeout t) { + struct timespec start; + ABSL_RAW_CHECK(clock_gettime(CLOCK_MONOTONIC, &start) == 0, + "clock_gettime() failed"); + + // Loop until we can atomically decrement futex from a positive + // value, waiting on a futex while we believe it is zero. + // Note that, since the thread ticker is just reset, we don't need to check + // whether the thread is idle on the very first pass of the loop. + bool first_pass = true; + + while (true) { + int32_t x = futex_.load(std::memory_order_relaxed); + while (x != 0) { + if (!futex_.compare_exchange_weak(x, x - 1, + std::memory_order_acquire, + std::memory_order_relaxed)) { + continue; // Raced with someone, retry. + } + return true; // Consumed a wakeup, we are done. + } + + auto relative_timeout = t.MakeRelativeTimespec(); + if (!first_pass) { + MaybeBecomeIdle(); + + // Adjust relative_timeout for `Poke()`s. + struct timespec now; + ABSL_RAW_CHECK(clock_gettime(CLOCK_MONOTONIC, &now) == 0, + "clock_gettime() failed"); + // If TimespecSubstract(now, start) returns false, then the clock isn't + // truly monotonic. + if (TimespecSubtract(now, start)) { + if (!TimespecSubtract(relative_timeout, now)) { + return false; // Timeout. + } + } + } + + const int err = Futex::WaitRelativeTimeout(&futex_, 0, &relative_timeout); if (err != 0) { if (err == -EINTR || err == -EWOULDBLOCK) { // Do nothing, the loop will retry. @@ -104,6 +183,23 @@ bool Waiter::Wait(KernelTimeout t) { } } +#else // CLOCK_MONOTONIC + +// No support for CLOCK_MONOTONIC. +// KernelTimeout will automatically convert to an absolute timeout. +bool Waiter::WaitRelativeTimeout(KernelTimeout t) { + return WaitAbsoluteTimeout(t); +} + +#endif // CLOCK_MONOTONIC + +bool Waiter::Wait(KernelTimeout t) { + if (t.is_absolute_timeout()) { + return WaitAbsoluteTimeout(t); + } + return WaitRelativeTimeout(t); +} + void Waiter::Post() { if (futex_.fetch_add(1, std::memory_order_release) == 0) { // We incremented from 0, need to wake a potential waiter. diff --git a/absl/synchronization/internal/waiter.h b/absl/synchronization/internal/waiter.h index b8adfeb5..c206cc3f 100644 --- a/absl/synchronization/internal/waiter.h +++ b/absl/synchronization/internal/waiter.h @@ -110,6 +110,9 @@ class Waiter { ~Waiter() = delete; #if ABSL_WAITER_MODE == ABSL_WAITER_MODE_FUTEX + bool WaitAbsoluteTimeout(KernelTimeout t); + bool WaitRelativeTimeout(KernelTimeout t); + // Futexes are defined by specification to be 32-bits. // Thus std::atomic<int32_t> must be just an int32_t with lockfree methods. std::atomic<int32_t> futex_; diff --git a/absl/synchronization/mutex.cc b/absl/synchronization/mutex.cc index 064ccb74..f6a8506c 100644 --- a/absl/synchronization/mutex.cc +++ b/absl/synchronization/mutex.cc @@ -635,21 +635,6 @@ void Mutex::InternalAttemptToUseMutexInFatalSignalHandler() { std::memory_order_release); } -// --------------------------time support - -// Return the current time plus the timeout. Use the same clock as -// PerThreadSem::Wait() for consistency. Unfortunately, we don't have -// such a choice when a deadline is given directly. -static absl::Time DeadlineFromTimeout(absl::Duration timeout) { -#ifndef _WIN32 - struct timeval tv; - gettimeofday(&tv, nullptr); - return absl::TimeFromTimeval(tv) + timeout; -#else - return absl::Now() + timeout; -#endif -} - // --------------------------Mutexes // In the layout below, the msb of the bottom byte is currently unused. Also, @@ -1546,7 +1531,13 @@ void Mutex::LockWhen(const Condition &cond) { } bool Mutex::LockWhenWithTimeout(const Condition &cond, absl::Duration timeout) { - return LockWhenWithDeadline(cond, DeadlineFromTimeout(timeout)); + ABSL_TSAN_MUTEX_PRE_LOCK(this, 0); + GraphId id = DebugOnlyDeadlockCheck(this); + bool res = LockSlowWithDeadline(kExclusive, &cond, + KernelTimeout(timeout), 0); + DebugOnlyLockEnter(this, id); + ABSL_TSAN_MUTEX_POST_LOCK(this, 0, 0); + return res; } bool Mutex::LockWhenWithDeadline(const Condition &cond, absl::Time deadline) { @@ -1569,7 +1560,12 @@ void Mutex::ReaderLockWhen(const Condition &cond) { bool Mutex::ReaderLockWhenWithTimeout(const Condition &cond, absl::Duration timeout) { - return ReaderLockWhenWithDeadline(cond, DeadlineFromTimeout(timeout)); + ABSL_TSAN_MUTEX_PRE_LOCK(this, __tsan_mutex_read_lock); + GraphId id = DebugOnlyDeadlockCheck(this); + bool res = LockSlowWithDeadline(kShared, &cond, KernelTimeout(timeout), 0); + DebugOnlyLockEnter(this, id); + ABSL_TSAN_MUTEX_POST_LOCK(this, __tsan_mutex_read_lock, 0); + return res; } bool Mutex::ReaderLockWhenWithDeadline(const Condition &cond, @@ -1594,7 +1590,18 @@ void Mutex::Await(const Condition &cond) { } bool Mutex::AwaitWithTimeout(const Condition &cond, absl::Duration timeout) { - return AwaitWithDeadline(cond, DeadlineFromTimeout(timeout)); + if (cond.Eval()) { // condition already true; nothing to do + if (kDebugMode) { + this->AssertReaderHeld(); + } + return true; + } + + KernelTimeout t{timeout}; + bool res = this->AwaitCommon(cond, t); + ABSL_RAW_CHECK(res || t.has_timeout(), + "condition untrue on return from Await"); + return res; } bool Mutex::AwaitWithDeadline(const Condition &cond, absl::Time deadline) { @@ -2660,7 +2667,7 @@ bool CondVar::WaitCommon(Mutex *mutex, KernelTimeout t) { } bool CondVar::WaitWithTimeout(Mutex *mu, absl::Duration timeout) { - return WaitWithDeadline(mu, DeadlineFromTimeout(timeout)); + return WaitCommon(mu, KernelTimeout(timeout)); } bool CondVar::WaitWithDeadline(Mutex *mu, absl::Time deadline) { diff --git a/absl/types/optional.h b/absl/types/optional.h index 134b2aff..e42ab4d0 100644 --- a/absl/types/optional.h +++ b/absl/types/optional.h @@ -130,7 +130,7 @@ class optional : private optional_internal::optional_data<T>, // Constructs an `optional` holding an empty value, NOT a default constructed // `T`. - constexpr optional() noexcept {} + constexpr optional() noexcept = default; // Constructs an `optional` initialized with `nullopt` to hold an empty value. constexpr optional(nullopt_t) noexcept {} // NOLINT(runtime/explicit) diff --git a/ci/linux_docker_containers.sh b/ci/linux_docker_containers.sh index 1dd8b74a..dcaf18b9 100644 --- a/ci/linux_docker_containers.sh +++ b/ci/linux_docker_containers.sh @@ -16,6 +16,6 @@ # Test scripts should source this file to get the identifiers. readonly LINUX_ALPINE_CONTAINER="gcr.io/google.com/absl-177019/alpine:20201026" -readonly LINUX_CLANG_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_hybrid-latest:20220217" -readonly LINUX_GCC_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_hybrid-latest:20220217" +readonly LINUX_CLANG_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_hybrid-latest:20230217" +readonly LINUX_GCC_LATEST_CONTAINER="gcr.io/google.com/absl-177019/linux_hybrid-latest:20230217" readonly LINUX_GCC_FLOOR_CONTAINER="gcr.io/google.com/absl-177019/linux_gcc-floor:20230120" |