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[ADT] Make DenseMapBase::swap the public entry point #167650

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Merged
merged 1 commit into from
Nov 12, 2025
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[ADT] Make DenseMapBase::swap the public entry point #167650

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24 changes: 16 additions & 8 deletions llvm/include/llvm/ADT/DenseMap.h
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Original file line number Diff line number Diff line change
Expand Up @@ -360,6 +360,12 @@ class DenseMapBase : public DebugEpochBase {
return getBuckets();
}

void swap(DerivedT &RHS) {
this->incrementEpoch();
RHS.incrementEpoch();
Comment on lines +363 to +365
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@kuhar kuhar Nov 12, 2025

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Is the epoch number something we could test for?

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@kazutakahirata kazutakahirata Nov 12, 2025

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Yes, in a somewhat limited manner. The epoch number is hiding in LLVM_ENABLE_ABI_BREAKING_CHECKS, so we could test it when the macro is on.

If turn it on ourselves in a unit test, then we might run into issues with other source files -- with two different definitions of DenseMap in a unit test executable.

derived().swapImpl(RHS);
}

protected:
DenseMapBase() = default;

Expand Down Expand Up @@ -736,7 +742,7 @@ class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,

DenseMap(DenseMap &&other) : BaseT() {
init(0);
swap(other);
this->swap(other);
}

template <typename InputIt> DenseMap(const InputIt &I, const InputIt &E) {
Expand All @@ -756,15 +762,15 @@ class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
deallocateBuckets();
}

void swap(DenseMap &RHS) {
this->incrementEpoch();
RHS.incrementEpoch();
private:
void swapImpl(DenseMap &RHS) {
std::swap(Buckets, RHS.Buckets);
std::swap(NumEntries, RHS.NumEntries);
std::swap(NumTombstones, RHS.NumTombstones);
std::swap(NumBuckets, RHS.NumBuckets);
}

public:
DenseMap &operator=(const DenseMap &other) {
if (&other != this)
this->copyFrom(other);
Expand All @@ -775,7 +781,7 @@ class DenseMap : public DenseMapBase<DenseMap<KeyT, ValueT, KeyInfoT, BucketT>,
this->destroyAll();
deallocateBuckets();
init(0);
swap(other);
this->swap(other);
return *this;
}

Expand Down Expand Up @@ -895,7 +901,7 @@ class SmallDenseMap

SmallDenseMap(SmallDenseMap &&other) : BaseT() {
init(0);
swap(other);
this->swap(other);
}

template <typename InputIt>
Expand All @@ -916,7 +922,8 @@ class SmallDenseMap
deallocateBuckets();
}

void swap(SmallDenseMap &RHS) {
private:
void swapImpl(SmallDenseMap &RHS) {
unsigned TmpNumEntries = RHS.NumEntries;
RHS.NumEntries = NumEntries;
NumEntries = TmpNumEntries;
Expand Down Expand Up @@ -987,6 +994,7 @@ class SmallDenseMap
new (SmallSide.getLargeRep()) LargeRep(std::move(TmpRep));
}

public:
SmallDenseMap &operator=(const SmallDenseMap &other) {
if (&other != this)
this->copyFrom(other);
Expand All @@ -997,7 +1005,7 @@ class SmallDenseMap
this->destroyAll();
deallocateBuckets();
init(0);
swap(other);
this->swap(other);
return *this;
}

Expand Down
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