diff options
Diffstat (limited to 'absl/flags/internal/flag.cc')
| -rw-r--r-- | absl/flags/internal/flag.cc | 73 |
1 files changed, 42 insertions, 31 deletions
diff --git a/absl/flags/internal/flag.cc b/absl/flags/internal/flag.cc index f3c424ad83d8..089567f7ae50 100644 --- a/absl/flags/internal/flag.cc +++ b/absl/flags/internal/flag.cc @@ -92,9 +92,9 @@ class FlagState : public flags_internal::FlagStateInterface { counter_(counter) {} ~FlagState() override { - if (flag_impl_->ValueStorageKind() != FlagValueStorageKind::kHeapAllocated) + if (flag_impl_->ValueStorageKind() != FlagValueStorageKind::kAlignedBuffer) return; - flags_internal::Delete(flag_impl_->op_, value_.dynamic); + flags_internal::Delete(flag_impl_->op_, value_.heap_allocated); } private: @@ -112,11 +112,11 @@ class FlagState : public flags_internal::FlagStateInterface { // Flag and saved flag data. FlagImpl* flag_impl_; union SavedValue { - explicit SavedValue(void* v) : dynamic(v) {} + explicit SavedValue(void* v) : heap_allocated(v) {} explicit SavedValue(int64_t v) : one_word(v) {} explicit SavedValue(flags_internal::AlignedTwoWords v) : two_words(v) {} - void* dynamic; + void* heap_allocated; int64_t one_word; flags_internal::AlignedTwoWords two_words; } value_; @@ -128,25 +128,33 @@ class FlagState : public flags_internal::FlagStateInterface { /////////////////////////////////////////////////////////////////////////////// // Flag implementation, which does not depend on flag value type. +DynValueDeleter::DynValueDeleter(FlagOpFn op_arg) : op(op_arg) {} + +void DynValueDeleter::operator()(void* ptr) const { + if (op == nullptr) return; + + Delete(op, ptr); +} + void FlagImpl::Init() { new (&data_guard_) absl::Mutex; // At this point the default_value_ always points to gen_func. - std::unique_ptr<void, DynValueDeleter> init_value( - (*default_value_.gen_func)(), DynValueDeleter{op_}); switch (ValueStorageKind()) { - case FlagValueStorageKind::kHeapAllocated: - HeapAllocatedValue() = init_value.release(); + case FlagValueStorageKind::kAlignedBuffer: + (*default_value_.gen_func)(AlignedBufferValue()); break; case FlagValueStorageKind::kOneWordAtomic: { - int64_t atomic_value; - std::memcpy(&atomic_value, init_value.get(), Sizeof(op_)); - OneWordValue().store(atomic_value, std::memory_order_release); + alignas(int64_t) std::array<char, sizeof(int64_t)> buf{}; + (*default_value_.gen_func)(buf.data()); + auto value = absl::bit_cast<int64_t>(buf); + OneWordValue().store(value, std::memory_order_release); break; } case FlagValueStorageKind::kTwoWordsAtomic: { - AlignedTwoWords atomic_value{0, 0}; - std::memcpy(&atomic_value, init_value.get(), Sizeof(op_)); + alignas(AlignedTwoWords) std::array<char, sizeof(AlignedTwoWords)> buf{}; + (*default_value_.gen_func)(buf.data()); + auto atomic_value = absl::bit_cast<AlignedTwoWords>(buf); TwoWordsValue().store(atomic_value, std::memory_order_release); break; } @@ -191,15 +199,16 @@ std::unique_ptr<void, DynValueDeleter> FlagImpl::MakeInitValue() const { if (DefaultKind() == FlagDefaultKind::kDynamicValue) { res = flags_internal::Clone(op_, default_value_.dynamic_value); } else { - res = (*default_value_.gen_func)(); + res = flags_internal::Alloc(op_); + (*default_value_.gen_func)(res); } return {res, DynValueDeleter{op_}}; } void FlagImpl::StoreValue(const void* src) { switch (ValueStorageKind()) { - case FlagValueStorageKind::kHeapAllocated: - Copy(op_, src, HeapAllocatedValue()); + case FlagValueStorageKind::kAlignedBuffer: + Copy(op_, src, AlignedBufferValue()); break; case FlagValueStorageKind::kOneWordAtomic: { int64_t one_word_val = 0; @@ -257,9 +266,9 @@ std::string FlagImpl::DefaultValue() const { std::string FlagImpl::CurrentValue() const { auto* guard = DataGuard(); // Make sure flag initialized switch (ValueStorageKind()) { - case FlagValueStorageKind::kHeapAllocated: { + case FlagValueStorageKind::kAlignedBuffer: { absl::MutexLock l(guard); - return flags_internal::Unparse(op_, HeapAllocatedValue()); + return flags_internal::Unparse(op_, AlignedBufferValue()); } case FlagValueStorageKind::kOneWordAtomic: { const auto one_word_val = @@ -318,9 +327,9 @@ std::unique_ptr<FlagStateInterface> FlagImpl::SaveState() { bool modified = modified_; bool on_command_line = on_command_line_; switch (ValueStorageKind()) { - case FlagValueStorageKind::kHeapAllocated: { + case FlagValueStorageKind::kAlignedBuffer: { return absl::make_unique<FlagState>( - this, flags_internal::Clone(op_, HeapAllocatedValue()), modified, + this, flags_internal::Clone(op_, AlignedBufferValue()), modified, on_command_line, counter_); } case FlagValueStorageKind::kOneWordAtomic: { @@ -345,8 +354,8 @@ bool FlagImpl::RestoreState(const FlagState& flag_state) { } switch (ValueStorageKind()) { - case FlagValueStorageKind::kHeapAllocated: - StoreValue(flag_state.value_.dynamic); + case FlagValueStorageKind::kAlignedBuffer: + StoreValue(flag_state.value_.heap_allocated); break; case FlagValueStorageKind::kOneWordAtomic: StoreValue(&flag_state.value_.one_word); @@ -363,25 +372,27 @@ bool FlagImpl::RestoreState(const FlagState& flag_state) { } template <typename StorageT> -typename StorageT::value_type& FlagImpl::OffsetValue() const { +StorageT* FlagImpl::OffsetValue() const { char* p = reinterpret_cast<char*>(const_cast<FlagImpl*>(this)); // The offset is deduced via Flag value type specific op_. size_t offset = flags_internal::ValueOffset(op_); - return reinterpret_cast<StorageT*>(p + offset)->value; + return reinterpret_cast<StorageT*>(p + offset); } -void*& FlagImpl::HeapAllocatedValue() const { - assert(ValueStorageKind() == FlagValueStorageKind::kHeapAllocated); - return OffsetValue<FlagHeapAllocatedValue>(); +void* FlagImpl::AlignedBufferValue() const { + assert(ValueStorageKind() == FlagValueStorageKind::kAlignedBuffer); + return OffsetValue<void>(); } + std::atomic<int64_t>& FlagImpl::OneWordValue() const { assert(ValueStorageKind() == FlagValueStorageKind::kOneWordAtomic); - return OffsetValue<FlagOneWordValue>(); + return OffsetValue<FlagOneWordValue>()->value; } + std::atomic<AlignedTwoWords>& FlagImpl::TwoWordsValue() const { assert(ValueStorageKind() == FlagValueStorageKind::kTwoWordsAtomic); - return OffsetValue<FlagTwoWordsValue>(); + return OffsetValue<FlagTwoWordsValue>()->value; } // Attempts to parse supplied `value` string using parsing routine in the `flag` @@ -406,9 +417,9 @@ std::unique_ptr<void, DynValueDeleter> FlagImpl::TryParse( void FlagImpl::Read(void* dst) const { auto* guard = DataGuard(); // Make sure flag initialized switch (ValueStorageKind()) { - case FlagValueStorageKind::kHeapAllocated: { + case FlagValueStorageKind::kAlignedBuffer: { absl::MutexLock l(guard); - flags_internal::CopyConstruct(op_, HeapAllocatedValue(), dst); + flags_internal::CopyConstruct(op_, AlignedBufferValue(), dst); break; } case FlagValueStorageKind::kOneWordAtomic: { |