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-rw-r--r--absl/container/internal/raw_hash_set.h110
1 files changed, 64 insertions, 46 deletions
diff --git a/absl/container/internal/raw_hash_set.h b/absl/container/internal/raw_hash_set.h
index 2880af70..970016f7 100644
--- a/absl/container/internal/raw_hash_set.h
+++ b/absl/container/internal/raw_hash_set.h
@@ -889,6 +889,11 @@ using CommonFieldsGenerationInfo = CommonFieldsGenerationInfoDisabled;
using HashSetIteratorGenerationInfo = HashSetIteratorGenerationInfoDisabled;
#endif
+// Returns whether `n` is a valid capacity (i.e., number of slots).
+//
+// A valid capacity is a non-zero integer `2^m - 1`.
+inline bool IsValidCapacity(size_t n) { return ((n + 1) & n) == 0 && n > 0; }
+
// CommonFields hold the fields in raw_hash_set that do not depend
// on template parameters. This allows us to conveniently pass all
// of this state to helper functions as a single argument.
@@ -906,21 +911,35 @@ class CommonFields : public CommonFieldsGenerationInfo {
std::move(static_cast<CommonFieldsGenerationInfo&&>(that))),
// Explicitly copying fields into "this" and then resetting "that"
// fields generates less code then calling absl::exchange per field.
- control_(that.control_),
- slots_(that.slots_),
- size_(that.size_),
- capacity_(that.capacity_),
+ control_(that.control()),
+ slots_(that.slots_ptr()),
+ size_(that.size()),
+ capacity_(that.capacity()),
compressed_tuple_(that.growth_left(), std::move(that.infoz())) {
- that.control_ = EmptyGroup();
- that.slots_ = nullptr;
- that.size_ = 0;
- that.capacity_ = 0;
- that.growth_left() = 0;
+ that.set_control(EmptyGroup());
+ that.set_slots(nullptr);
+ that.set_size(0);
+ that.set_capacity(0);
+ that.set_growth_left(0);
}
CommonFields& operator=(CommonFields&&) = default;
+ ctrl_t* control() const { return control_; }
+ void set_control(ctrl_t* c) { control_ = c; }
+ // Note: we can't use slots() because Qt defines "slots" as a macro.
+ void* slots_ptr() const { return slots_; }
+ void set_slots(void* s) { slots_ = s; }
+ size_t size() const { return size_; }
+ void set_size(size_t s) { size_ = s; }
+ size_t capacity() const { return capacity_; }
+ void set_capacity(size_t c) {
+ assert(c == 0 || IsValidCapacity(c));
+ capacity_ = c;
+ }
+
// The number of slots we can still fill without needing to rehash.
- size_t& growth_left() { return compressed_tuple_.template get<0>(); }
+ size_t growth_left() const { return compressed_tuple_.template get<0>(); }
+ void set_growth_left(size_t gl) { compressed_tuple_.template get<0>() = gl; }
HashtablezInfoHandle& infoz() { return compressed_tuple_.template get<1>(); }
const HashtablezInfoHandle& infoz() const {
@@ -929,15 +948,17 @@ class CommonFields : public CommonFieldsGenerationInfo {
bool should_rehash_for_bug_detection_on_insert() const {
return CommonFieldsGenerationInfo::
- should_rehash_for_bug_detection_on_insert(control_, capacity_);
+ should_rehash_for_bug_detection_on_insert(control(), capacity());
}
void reset_reserved_growth(size_t reservation) {
CommonFieldsGenerationInfo::reset_reserved_growth(reservation, size_);
}
+ private:
// TODO(b/259599413): Investigate removing some of these fields:
// - control/slots can be derived from each other
- // - size can be moved into the slot array
+ // - growth_left can be moved into the slot array
+ // - we can use 6 bits for capacity since it's always a power of two minus 1
// The control bytes (and, also, a pointer to the base of the backing array).
//
@@ -971,11 +992,6 @@ constexpr size_t NumClonedBytes() { return Group::kWidth - 1; }
template <class Policy, class Hash, class Eq, class Alloc>
class raw_hash_set;
-// Returns whether `n` is a valid capacity (i.e., number of slots).
-//
-// A valid capacity is a non-zero integer `2^m - 1`.
-inline bool IsValidCapacity(size_t n) { return ((n + 1) & n) == 0 && n > 0; }
-
// Returns the next valid capacity after `n`.
inline size_t NextCapacity(size_t n) {
assert(IsValidCapacity(n) || n == 0);
@@ -1216,7 +1232,7 @@ inline probe_seq<Group::kWidth> probe(const ctrl_t* ctrl, const size_t capacity,
return probe_seq<Group::kWidth>(H1(hash, ctrl), capacity);
}
inline probe_seq<Group::kWidth> probe(const CommonFields& common, size_t hash) {
- return probe(common.control_, common.capacity_, hash);
+ return probe(common.control(), common.capacity(), hash);
}
// Probes an array of control bits using a probe sequence derived from `hash`,
@@ -1229,7 +1245,7 @@ inline probe_seq<Group::kWidth> probe(const CommonFields& common, size_t hash) {
template <typename = void>
inline FindInfo find_first_non_full(const CommonFields& common, size_t hash) {
auto seq = probe(common, hash);
- const ctrl_t* ctrl = common.control_;
+ const ctrl_t* ctrl = common.control();
while (true) {
Group g{ctrl + seq.offset()};
auto mask = g.MaskEmptyOrDeleted();
@@ -1239,14 +1255,14 @@ inline FindInfo find_first_non_full(const CommonFields& common, size_t hash) {
// In debug build we will randomly insert in either the front or back of
// the group.
// TODO(kfm,sbenza): revisit after we do unconditional mixing
- if (!is_small(common.capacity_) && ShouldInsertBackwards(hash, ctrl)) {
+ if (!is_small(common.capacity()) && ShouldInsertBackwards(hash, ctrl)) {
return {seq.offset(mask.HighestBitSet()), seq.index()};
}
#endif
return {seq.offset(mask.LowestBitSet()), seq.index()};
}
seq.next();
- assert(seq.index() <= common.capacity_ && "full table!");
+ assert(seq.index() <= common.capacity() && "full table!");
}
}
@@ -1260,18 +1276,18 @@ extern template FindInfo find_first_non_full(const CommonFields&, size_t);
FindInfo find_first_non_full_outofline(const CommonFields&, size_t);
inline void ResetGrowthLeft(CommonFields& common) {
- common.growth_left() = CapacityToGrowth(common.capacity_) - common.size_;
+ common.set_growth_left(CapacityToGrowth(common.capacity()) - common.size());
}
// Sets `ctrl` to `{kEmpty, kSentinel, ..., kEmpty}`, marking the entire
// array as marked as empty.
inline void ResetCtrl(CommonFields& common, size_t slot_size) {
- const size_t capacity = common.capacity_;
- ctrl_t* ctrl = common.control_;
+ const size_t capacity = common.capacity();
+ ctrl_t* ctrl = common.control();
std::memset(ctrl, static_cast<int8_t>(ctrl_t::kEmpty),
capacity + 1 + NumClonedBytes());
ctrl[capacity] = ctrl_t::kSentinel;
- SanitizerPoisonMemoryRegion(common.slots_, slot_size * capacity);
+ SanitizerPoisonMemoryRegion(common.slots_ptr(), slot_size * capacity);
ResetGrowthLeft(common);
}
@@ -1281,17 +1297,17 @@ inline void ResetCtrl(CommonFields& common, size_t slot_size) {
// mirror the value to the cloned tail if necessary.
inline void SetCtrl(const CommonFields& common, size_t i, ctrl_t h,
size_t slot_size) {
- const size_t capacity = common.capacity_;
+ const size_t capacity = common.capacity();
assert(i < capacity);
- auto* slot_i = static_cast<const char*>(common.slots_) + i * slot_size;
+ auto* slot_i = static_cast<const char*>(common.slots_ptr()) + i * slot_size;
if (IsFull(h)) {
SanitizerUnpoisonMemoryRegion(slot_i, slot_size);
} else {
SanitizerPoisonMemoryRegion(slot_i, slot_size);
}
- ctrl_t* ctrl = common.control_;
+ ctrl_t* ctrl = common.control();
ctrl[i] = h;
ctrl[((i - NumClonedBytes()) & capacity) + (NumClonedBytes() & capacity)] = h;
}
@@ -1327,31 +1343,32 @@ inline size_t AllocSize(size_t capacity, size_t slot_size, size_t slot_align) {
template <typename Alloc, size_t SizeOfSlot, size_t AlignOfSlot>
ABSL_ATTRIBUTE_NOINLINE void InitializeSlots(CommonFields& c, Alloc alloc) {
- assert(c.capacity_);
+ assert(c.capacity());
// Folks with custom allocators often make unwarranted assumptions about the
// behavior of their classes vis-a-vis trivial destructability and what
// calls they will or won't make. Avoid sampling for people with custom
// allocators to get us out of this mess. This is not a hard guarantee but
// a workaround while we plan the exact guarantee we want to provide.
const size_t sample_size =
- (std::is_same<Alloc, std::allocator<char>>::value && c.slots_ == nullptr)
+ (std::is_same<Alloc, std::allocator<char>>::value &&
+ c.slots_ptr() == nullptr)
? SizeOfSlot
: 0;
- const size_t cap = c.capacity_;
+ const size_t cap = c.capacity();
char* mem = static_cast<char*>(
Allocate<AlignOfSlot>(&alloc, AllocSize(cap, SizeOfSlot, AlignOfSlot)));
const GenerationType old_generation = c.generation();
c.set_generation_ptr(
reinterpret_cast<GenerationType*>(mem + GenerationOffset(cap)));
c.set_generation(NextGeneration(old_generation));
- c.control_ = reinterpret_cast<ctrl_t*>(mem);
- c.slots_ = mem + SlotOffset(cap, AlignOfSlot);
+ c.set_control(reinterpret_cast<ctrl_t*>(mem));
+ c.set_slots(mem + SlotOffset(cap, AlignOfSlot));
ResetCtrl(c, SizeOfSlot);
if (sample_size) {
c.infoz() = Sample(sample_size);
}
- c.infoz().RecordStorageChanged(c.size_, cap);
+ c.infoz().RecordStorageChanged(c.size(), cap);
}
// PolicyFunctions bundles together some information for a particular
@@ -1654,7 +1671,7 @@ class raw_hash_set {
const allocator_type& alloc = allocator_type())
: settings_(CommonFields{}, hash, eq, alloc) {
if (bucket_count) {
- common().capacity_ = NormalizeCapacity(bucket_count);
+ common().set_capacity(NormalizeCapacity(bucket_count));
initialize_slots();
}
}
@@ -1767,8 +1784,8 @@ class raw_hash_set {
common().maybe_increment_generation_on_insert();
infoz().RecordInsert(hash, target.probe_length);
}
- common().size_ = that.size();
- growth_left() -= that.size();
+ common().set_size(that.size());
+ set_growth_left(growth_left() - that.size());
}
ABSL_ATTRIBUTE_NOINLINE raw_hash_set(raw_hash_set&& that) noexcept(
@@ -1849,8 +1866,8 @@ class raw_hash_set {
const_iterator cend() const ABSL_ATTRIBUTE_LIFETIME_BOUND { return end(); }
bool empty() const { return !size(); }
- size_t size() const { return common().size_; }
- size_t capacity() const { return common().capacity_; }
+ size_t size() const { return common().size(); }
+ size_t capacity() const { return common().capacity(); }
size_t max_size() const { return (std::numeric_limits<size_t>::max)(); }
ABSL_ATTRIBUTE_REINITIALIZES void clear() {
@@ -2432,8 +2449,8 @@ class raw_hash_set {
assert(IsValidCapacity(new_capacity));
auto* old_ctrl = control();
auto* old_slots = slot_array();
- const size_t old_capacity = common().capacity_;
- common().capacity_ = new_capacity;
+ const size_t old_capacity = common().capacity();
+ common().set_capacity(new_capacity);
initialize_slots();
auto* new_slots = slot_array();
@@ -2600,8 +2617,8 @@ class raw_hash_set {
rehash_and_grow_if_necessary();
target = find_first_non_full(common(), hash);
}
- ++common().size_;
- growth_left() -= IsEmpty(control()[target.offset]);
+ common().set_size(common().size() + 1);
+ set_growth_left(growth_left() - IsEmpty(control()[target.offset]));
SetCtrl(common(), target.offset, H2(hash), sizeof(slot_type));
common().maybe_increment_generation_on_insert();
infoz().RecordInsert(hash, target.probe_length);
@@ -2646,7 +2663,8 @@ class raw_hash_set {
// side-effect.
//
// See `CapacityToGrowth()`.
- size_t& growth_left() { return common().growth_left(); }
+ size_t growth_left() const { return common().growth_left(); }
+ void set_growth_left(size_t gl) { return common().set_growth_left(gl); }
// Prefetch the heap-allocated memory region to resolve potential TLB and
// cache misses. This is intended to overlap with execution of calculating the
@@ -2660,9 +2678,9 @@ class raw_hash_set {
CommonFields& common() { return settings_.template get<0>(); }
const CommonFields& common() const { return settings_.template get<0>(); }
- ctrl_t* control() const { return common().control_; }
+ ctrl_t* control() const { return common().control(); }
slot_type* slot_array() const {
- return static_cast<slot_type*>(common().slots_);
+ return static_cast<slot_type*>(common().slots_ptr());
}
HashtablezInfoHandle& infoz() { return common().infoz(); }
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-10 05:06:04 +0000