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abseil-cpp
Commit c44dd5ac by Abseil Team Committed by Copybara-Service
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Early return from destroy_slots for trivially destructible types in flat_hash_{*}. 

PiperOrigin-RevId: 602813933
Change-Id: I744fe438281755a141b2fd47e54ab9c6c0fad5a3
parent 779a3565
Showing with 122 additions and 27 deletions
absl/container/BUILD.bazel
...@@ -264,6 +264,7 @@ cc_test( ...@@ -264,6 +264,7 @@ cc_test(
deps = [ deps = [
":flat_hash_map", ":flat_hash_map",
":hash_generator_testing", ":hash_generator_testing",
":test_allocator",
":unordered_map_constructor_test", ":unordered_map_constructor_test",
":unordered_map_lookup_test", ":unordered_map_lookup_test",
":unordered_map_members_test", ":unordered_map_members_test",
...@@ -301,6 +302,7 @@ cc_test( ...@@ -301,6 +302,7 @@ cc_test(
":container_memory", ":container_memory",
":flat_hash_set", ":flat_hash_set",
":hash_generator_testing", ":hash_generator_testing",
":test_allocator",
":unordered_set_constructor_test", ":unordered_set_constructor_test",
":unordered_set_lookup_test", ":unordered_set_lookup_test",
":unordered_set_members_test", ":unordered_set_members_test",
......
absl/container/CMakeLists.txt
...@@ -307,6 +307,7 @@ absl_cc_test( ...@@ -307,6 +307,7 @@ absl_cc_test(
absl::check absl::check
absl::flat_hash_map absl::flat_hash_map
absl::hash_generator_testing absl::hash_generator_testing
absl::test_allocator
absl::type_traits absl::type_traits
absl::unordered_map_constructor_test absl::unordered_map_constructor_test
absl::unordered_map_lookup_test absl::unordered_map_lookup_test
...@@ -348,6 +349,7 @@ absl_cc_test( ...@@ -348,6 +349,7 @@ absl_cc_test(
absl::hash_generator_testing absl::hash_generator_testing
absl::memory absl::memory
absl::strings absl::strings
absl::test_allocator
absl::unordered_set_constructor_test absl::unordered_set_constructor_test
absl::unordered_set_lookup_test absl::unordered_set_lookup_test
absl::unordered_set_members_test absl::unordered_set_members_test
......
absl/container/flat_hash_map.h
...@@ -573,9 +573,10 @@ struct FlatHashMapPolicy { ...@@ -573,9 +573,10 @@ struct FlatHashMapPolicy {
slot_policy::construct(alloc, slot, std::forward<Args>(args)...); slot_policy::construct(alloc, slot, std::forward<Args>(args)...);
} }
// Returns std::true_type in case destroy is trivial.
template <class Allocator> template <class Allocator>
static void destroy(Allocator* alloc, slot_type* slot) { static auto destroy(Allocator* alloc, slot_type* slot) {
slot_policy::destroy(alloc, slot); return slot_policy::destroy(alloc, slot);
} }
template <class Allocator> template <class Allocator>
......
absl/container/flat_hash_map_test.cc
...@@ -22,6 +22,7 @@ ...@@ -22,6 +22,7 @@
#include "gtest/gtest.h" #include "gtest/gtest.h"
#include "absl/container/internal/hash_generator_testing.h" #include "absl/container/internal/hash_generator_testing.h"
#include "absl/container/internal/test_allocator.h"
#include "absl/container/internal/unordered_map_constructor_test.h" #include "absl/container/internal/unordered_map_constructor_test.h"
#include "absl/container/internal/unordered_map_lookup_test.h" #include "absl/container/internal/unordered_map_lookup_test.h"
#include "absl/container/internal/unordered_map_members_test.h" #include "absl/container/internal/unordered_map_members_test.h"
...@@ -351,6 +352,17 @@ TEST(FlatHashMap, RecursiveTypeCompiles) { ...@@ -351,6 +352,17 @@ TEST(FlatHashMap, RecursiveTypeCompiles) {
t.m[0] = RecursiveType{}; t.m[0] = RecursiveType{};
} }
TEST(FlatHashMap, FlatHashMapPolicyDestroyReturnsTrue) {
EXPECT_TRUE(
(decltype(FlatHashMapPolicy<int, char>::destroy<std::allocator<char>>(
nullptr, nullptr))()));
EXPECT_FALSE(
(decltype(FlatHashMapPolicy<int, char>::destroy<CountingAllocator<char>>(
nullptr, nullptr))()));
EXPECT_FALSE((decltype(FlatHashMapPolicy<int, std::unique_ptr<int>>::destroy<
std::allocator<char>>(nullptr, nullptr))()));
}
} // namespace } // namespace
} // namespace container_internal } // namespace container_internal
ABSL_NAMESPACE_END ABSL_NAMESPACE_END
......
absl/container/flat_hash_set.h
...@@ -29,6 +29,7 @@ ...@@ -29,6 +29,7 @@
#ifndef ABSL_CONTAINER_FLAT_HASH_SET_H_ #ifndef ABSL_CONTAINER_FLAT_HASH_SET_H_
#define ABSL_CONTAINER_FLAT_HASH_SET_H_ #define ABSL_CONTAINER_FLAT_HASH_SET_H_
#include <memory>
#include <type_traits> #include <type_traits>
#include <utility> #include <utility>
...@@ -473,9 +474,11 @@ struct FlatHashSetPolicy { ...@@ -473,9 +474,11 @@ struct FlatHashSetPolicy {
std::forward<Args>(args)...); std::forward<Args>(args)...);
} }
// Return std::true_type in case destroy is trivial.
template <class Allocator> template <class Allocator>
static void destroy(Allocator* alloc, slot_type* slot) { static auto destroy(Allocator* alloc, slot_type* slot) {
absl::allocator_traits<Allocator>::destroy(*alloc, slot); absl::allocator_traits<Allocator>::destroy(*alloc, slot);
return IsDestructionTrivial<Allocator, slot_type>();
} }
static T& element(slot_type* slot) { return *slot; } static T& element(slot_type* slot) { return *slot; }
......
absl/container/flat_hash_set_test.cc
...@@ -16,6 +16,7 @@ ...@@ -16,6 +16,7 @@
#include <cstdint> #include <cstdint>
#include <memory> #include <memory>
#include <type_traits>
#include <utility> #include <utility>
#include <vector> #include <vector>
...@@ -24,6 +25,7 @@ ...@@ -24,6 +25,7 @@
#include "absl/base/config.h" #include "absl/base/config.h"
#include "absl/container/internal/container_memory.h" #include "absl/container/internal/container_memory.h"
#include "absl/container/internal/hash_generator_testing.h" #include "absl/container/internal/hash_generator_testing.h"
#include "absl/container/internal/test_allocator.h"
#include "absl/container/internal/unordered_set_constructor_test.h" #include "absl/container/internal/unordered_set_constructor_test.h"
#include "absl/container/internal/unordered_set_lookup_test.h" #include "absl/container/internal/unordered_set_lookup_test.h"
#include "absl/container/internal/unordered_set_members_test.h" #include "absl/container/internal/unordered_set_members_test.h"
...@@ -237,6 +239,16 @@ TEST(FlatHashSet, PoisonInline) { ...@@ -237,6 +239,16 @@ TEST(FlatHashSet, PoisonInline) {
} }
} }
TEST(FlatHashSet, FlatHashSetPolicyDestroyReturnsTrue) {
EXPECT_TRUE((decltype(FlatHashSetPolicy<int>::destroy<std::allocator<int>>(
nullptr, nullptr))()));
EXPECT_FALSE(
(decltype(FlatHashSetPolicy<int>::destroy<CountingAllocator<int>>(
nullptr, nullptr))()));
EXPECT_FALSE((decltype(FlatHashSetPolicy<std::unique_ptr<int>>::destroy<
std::allocator<int>>(nullptr, nullptr))()));
}
} // namespace } // namespace
} // namespace container_internal } // namespace container_internal
ABSL_NAMESPACE_END ABSL_NAMESPACE_END
......
absl/container/internal/common_policy_traits.h
...@@ -45,9 +45,10 @@ struct common_policy_traits { ...@@ -45,9 +45,10 @@ struct common_policy_traits {
// PRECONDITION: `slot` is INITIALIZED // PRECONDITION: `slot` is INITIALIZED
// POSTCONDITION: `slot` is UNINITIALIZED // POSTCONDITION: `slot` is UNINITIALIZED
// Returns std::true_type in case destroy is trivial.
template <class Alloc> template <class Alloc>
static void destroy(Alloc* alloc, slot_type* slot) { static auto destroy(Alloc* alloc, slot_type* slot) {
Policy::destroy(alloc, slot); return Policy::destroy(alloc, slot);
} }
// Transfers the `old_slot` to `new_slot`. Any memory allocated by the // Transfers the `old_slot` to `new_slot`. Any memory allocated by the
...@@ -86,6 +87,13 @@ struct common_policy_traits { ...@@ -86,6 +87,13 @@ struct common_policy_traits {
std::true_type>::value; std::true_type>::value;
} }
// Returns true if destroy is trivial and can be omitted.
template <class Alloc>
static constexpr bool destroy_is_trivial() {
return std::is_same<decltype(destroy<Alloc>(nullptr, nullptr)),
std::true_type>::value;
}
private: private:
// To rank the overloads below for overload resolution. Rank0 is preferred. // To rank the overloads below for overload resolution. Rank0 is preferred.
struct Rank2 {}; struct Rank2 {};
......
absl/container/internal/common_policy_traits_test.cc
...@@ -39,44 +39,59 @@ struct PolicyWithoutOptionalOps { ...@@ -39,44 +39,59 @@ struct PolicyWithoutOptionalOps {
using key_type = Slot; using key_type = Slot;
using init_type = Slot; using init_type = Slot;
static std::function<void(void*, Slot*, Slot)> construct; struct PolicyFunctions {
static std::function<void(void*, Slot*)> destroy; std::function<void(void*, Slot*, Slot)> construct;
std::function<void(void*, Slot*)> destroy;
std::function<Slot&(Slot*)> element;
};
static PolicyFunctions* functions() {
static PolicyFunctions* functions = new PolicyFunctions();
return functions;
}
static std::function<Slot&(Slot*)> element; static void construct(void* a, Slot* b, Slot c) {
functions()->construct(a, b, c);
}
static void destroy(void* a, Slot* b) { functions()->destroy(a, b); }
static Slot& element(Slot* b) { return functions()->element(b); }
}; };
std::function<void(void*, Slot*, Slot)> PolicyWithoutOptionalOps::construct;
std::function<void(void*, Slot*)> PolicyWithoutOptionalOps::destroy;
std::function<Slot&(Slot*)> PolicyWithoutOptionalOps::element;
struct PolicyWithOptionalOps : PolicyWithoutOptionalOps { struct PolicyWithOptionalOps : PolicyWithoutOptionalOps {
static std::function<void(void*, Slot*, Slot*)> transfer; struct TransferFunctions {
std::function<void(void*, Slot*, Slot*)> transfer;
};
static TransferFunctions* transfer_fn() {
static TransferFunctions* transfer_fn = new TransferFunctions();
return transfer_fn;
}
static void transfer(void* a, Slot* b, Slot* c) {
transfer_fn()->transfer(a, b, c);
}
}; };
std::function<void(void*, Slot*, Slot*)> PolicyWithOptionalOps::transfer;
struct PolicyWithMemcpyTransfer : PolicyWithoutOptionalOps { struct PolicyWithMemcpyTransferAndTrivialDestroy : PolicyWithoutOptionalOps {
static std::function<std::true_type(void*, Slot*, Slot*)> transfer; static std::true_type transfer(void*, Slot*, Slot*) { return {}; }
static std::true_type destroy(void*, Slot*) { return {}; }
}; };
std::function<std::true_type(void*, Slot*, Slot*)>
PolicyWithMemcpyTransfer::transfer;
struct Test : ::testing::Test { struct Test : ::testing::Test {
Test() { Test() {
PolicyWithoutOptionalOps::construct = [&](void* a1, Slot* a2, Slot a3) { PolicyWithoutOptionalOps::functions()->construct = [&](void* a1, Slot* a2,
Slot a3) {
construct.Call(a1, a2, std::move(a3)); construct.Call(a1, a2, std::move(a3));
}; };
PolicyWithoutOptionalOps::destroy = [&](void* a1, Slot* a2) { PolicyWithoutOptionalOps::functions()->destroy = [&](void* a1, Slot* a2) {
destroy.Call(a1, a2); destroy.Call(a1, a2);
}; };
PolicyWithoutOptionalOps::element = [&](Slot* a1) -> Slot& { PolicyWithoutOptionalOps::functions()->element = [&](Slot* a1) -> Slot& {
return element.Call(a1); return element.Call(a1);
}; };
PolicyWithOptionalOps::transfer = [&](void* a1, Slot* a2, Slot* a3) { PolicyWithOptionalOps::transfer_fn()->transfer =
return transfer.Call(a1, a2, a3); [&](void* a1, Slot* a2, Slot* a3) { return transfer.Call(a1, a2, a3); };
};
} }
std::allocator<Slot> alloc; std::allocator<Slot> alloc;
...@@ -125,7 +140,15 @@ TEST(TransferUsesMemcpy, Basic) { ...@@ -125,7 +140,15 @@ TEST(TransferUsesMemcpy, Basic) {
EXPECT_FALSE( EXPECT_FALSE(
common_policy_traits<PolicyWithOptionalOps>::transfer_uses_memcpy()); common_policy_traits<PolicyWithOptionalOps>::transfer_uses_memcpy());
EXPECT_TRUE( EXPECT_TRUE(
common_policy_traits<PolicyWithMemcpyTransfer>::transfer_uses_memcpy()); common_policy_traits<
PolicyWithMemcpyTransferAndTrivialDestroy>::transfer_uses_memcpy());
}
TEST(DestroyIsTrivial, Basic) {
EXPECT_FALSE(common_policy_traits<PolicyWithOptionalOps>::destroy_is_trivial<
std::allocator<char>>());
EXPECT_TRUE(common_policy_traits<PolicyWithMemcpyTransferAndTrivialDestroy>::
destroy_is_trivial<std::allocator<char>>());
} }
} // namespace } // namespace
......
absl/container/internal/container_memory.h
...@@ -68,6 +68,18 @@ void* Allocate(Alloc* alloc, size_t n) { ...@@ -68,6 +68,18 @@ void* Allocate(Alloc* alloc, size_t n) {
return p; return p;
} }
// Returns true if the destruction of the value with given Allocator will be
// trivial.
template <class Allocator, class ValueType>
constexpr auto IsDestructionTrivial() {
constexpr bool result =
std::is_trivially_destructible<ValueType>::value &&
std::is_same<typename absl::allocator_traits<
Allocator>::template rebind_alloc<char>,
std::allocator<char>>::value;
return std::integral_constant<bool, result>();
}
// The pointer must have been previously obtained by calling // The pointer must have been previously obtained by calling
// Allocate<Alignment>(alloc, n). // Allocate<Alignment>(alloc, n).
template <size_t Alignment, class Alloc> template <size_t Alignment, class Alloc>
...@@ -414,12 +426,13 @@ struct map_slot_policy { ...@@ -414,12 +426,13 @@ struct map_slot_policy {
} }
template <class Allocator> template <class Allocator>
static void destroy(Allocator* alloc, slot_type* slot) { static auto destroy(Allocator* alloc, slot_type* slot) {
if (kMutableKeys::value) { if (kMutableKeys::value) {
absl::allocator_traits<Allocator>::destroy(*alloc, &slot->mutable_value); absl::allocator_traits<Allocator>::destroy(*alloc, &slot->mutable_value);
} else { } else {
absl::allocator_traits<Allocator>::destroy(*alloc, &slot->value); absl::allocator_traits<Allocator>::destroy(*alloc, &slot->value);
} }
return IsDestructionTrivial<Allocator, value_type>();
} }
template <class Allocator> template <class Allocator>
......
absl/container/internal/container_memory_test.cc
...@@ -280,6 +280,24 @@ TEST(MapSlotPolicy, TransferReturnsTrue) { ...@@ -280,6 +280,24 @@ TEST(MapSlotPolicy, TransferReturnsTrue) {
} }
} }
TEST(MapSlotPolicy, DestroyReturnsTrue) {
{
using slot_policy = map_slot_policy<int, float>;
EXPECT_TRUE(
(std::is_same<decltype(slot_policy::destroy<std::allocator<char>>(
nullptr, nullptr)),
std::true_type>::value));
}
{
EXPECT_FALSE(std::is_trivially_destructible<std::unique_ptr<int>>::value);
using slot_policy = map_slot_policy<int, std::unique_ptr<int>>;
EXPECT_TRUE(
(std::is_same<decltype(slot_policy::destroy<std::allocator<char>>(
nullptr, nullptr)),
std::false_type>::value));
}
}
} // namespace } // namespace
} // namespace container_internal } // namespace container_internal
ABSL_NAMESPACE_END ABSL_NAMESPACE_END
......
absl/container/internal/raw_hash_set.h
...@@ -2881,6 +2881,7 @@ class raw_hash_set { ...@@ -2881,6 +2881,7 @@ class raw_hash_set {
} }
inline void destroy_slots() { inline void destroy_slots() {
if (PolicyTraits::template destroy_is_trivial<Alloc>()) return;
const size_t cap = capacity(); const size_t cap = capacity();
const ctrl_t* ctrl = control(); const ctrl_t* ctrl = control();
slot_type* slot = slot_array(); slot_type* slot = slot_array();
......
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