Give SmallPtrSet move semantics when we have R-value references.

Somehow, this ADT got missed which is moderately terrifying considering
the efficiency of move for it.

The code to implement move semantics for it is pretty horrible
currently but was written to reasonably closely match the rest of the
code. Unittests that cover both copying and moving (at a basic level)
added.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195239 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2013-11-20 11:14:33 +00:00
parent 56b09220a3
commit 46198164b3
3 changed files with 115 additions and 5 deletions

View File

@ -60,8 +60,12 @@ protected:
unsigned NumElements;
unsigned NumTombstones;
// Helper to copy construct a SmallPtrSet.
SmallPtrSetImpl(const void **SmallStorage, const SmallPtrSetImpl& that);
// Helpers to copy and move construct a SmallPtrSet.
SmallPtrSetImpl(const void **SmallStorage, const SmallPtrSetImpl &that);
#if LLVM_HAS_RVALUE_REFERENCES
SmallPtrSetImpl(const void **SmallStorage, unsigned SmallSize,
SmallPtrSetImpl &&that);
#endif
explicit SmallPtrSetImpl(const void **SmallStorage, unsigned SmallSize) :
SmallArray(SmallStorage), CurArray(SmallStorage), CurArraySize(SmallSize) {
assert(SmallSize && (SmallSize & (SmallSize-1)) == 0 &&
@ -135,6 +139,9 @@ protected:
void swap(SmallPtrSetImpl &RHS);
void CopyFrom(const SmallPtrSetImpl &RHS);
#if LLVM_HAS_RVALUE_REFERENCES
void MoveFrom(SmallPtrSetImpl &&RHS);
#endif
};
/// SmallPtrSetIteratorImpl - This is the common base class shared between all
@ -242,6 +249,10 @@ class SmallPtrSet : public SmallPtrSetImpl {
public:
SmallPtrSet() : SmallPtrSetImpl(SmallStorage, SmallSizePowTwo) {}
SmallPtrSet(const SmallPtrSet &that) : SmallPtrSetImpl(SmallStorage, that) {}
#if LLVM_HAS_RVALUE_REFERENCES
SmallPtrSet(SmallPtrSet &&that)
: SmallPtrSetImpl(SmallStorage, SmallSizePowTwo, std::move(that)) {}
#endif
template<typename It>
SmallPtrSet(It I, It E) : SmallPtrSetImpl(SmallStorage, SmallSizePowTwo) {
@ -280,14 +291,20 @@ public:
return iterator(CurArray+CurArraySize, CurArray+CurArraySize);
}
// Allow assignment from any smallptrset with the same element type even if it
// doesn't have the same smallsize.
const SmallPtrSet<PtrType, SmallSize>&
SmallPtrSet<PtrType, SmallSize> &
operator=(const SmallPtrSet<PtrType, SmallSize> &RHS) {
CopyFrom(RHS);
return *this;
}
#if LLVM_HAS_RVALUE_REFERENCES
SmallPtrSet<PtrType, SmallSize>&
operator=(SmallPtrSet<PtrType, SmallSize> &&RHS) {
MoveFrom(std::move(RHS));
return *this;
}
#endif
/// swap - Swaps the elements of two sets.
void swap(SmallPtrSet<PtrType, SmallSize> &RHS) {
SmallPtrSetImpl::swap(RHS);

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@ -186,6 +186,29 @@ SmallPtrSetImpl::SmallPtrSetImpl(const void **SmallStorage,
NumTombstones = that.NumTombstones;
}
#if LLVM_HAS_RVALUE_REFERENCES
SmallPtrSetImpl::SmallPtrSetImpl(const void **SmallStorage, unsigned SmallSize,
SmallPtrSetImpl &&that) {
SmallArray = SmallStorage;
// Copy over the basic members.
CurArraySize = that.CurArraySize;
NumElements = that.NumElements;
NumTombstones = that.NumTombstones;
// When small, just copy into our small buffer.
if (that.isSmall()) {
CurArray = SmallArray;
memcpy(CurArray, that.CurArray, sizeof(void *) * CurArraySize);
return;
}
// Otherwise, we steal the large memory allocation and no copy is needed.
CurArray = that.CurArray;
that.CurArray = that.SmallArray;
}
#endif
/// CopyFrom - implement operator= from a smallptrset that has the same pointer
/// type, but may have a different small size.
void SmallPtrSetImpl::CopyFrom(const SmallPtrSetImpl &RHS) {
@ -222,6 +245,27 @@ void SmallPtrSetImpl::CopyFrom(const SmallPtrSetImpl &RHS) {
NumTombstones = RHS.NumTombstones;
}
#if LLVM_HAS_RVALUE_REFERENCES
void SmallPtrSetImpl::MoveFrom(SmallPtrSetImpl &&RHS) {
if (!isSmall())
free(CurArray);
if (RHS.isSmall()) {
// Copy a small RHS rather than moving.
CurArray = SmallArray;
memcpy(CurArray, RHS.CurArray, sizeof(void*)*RHS.CurArraySize);
} else {
CurArray = RHS.CurArray;
RHS.CurArray = RHS.SmallArray;
}
// Copy the rest of the trivial members.
CurArraySize = RHS.CurArraySize;
NumElements = RHS.NumElements;
NumTombstones = RHS.NumTombstones;
}
#endif
void SmallPtrSetImpl::swap(SmallPtrSetImpl &RHS) {
if (this == &RHS) return;

View File

@ -71,6 +71,55 @@ TEST(SmallPtrSetTest, GrowthTest) {
EXPECT_EQ(1,buf[i]);
}
TEST(SmallPtrSetTest, CopyAndMoveTest) {
int buf[8];
for (int i = 0; i < 8; ++i)
buf[i] = 0;
SmallPtrSet<int *, 4> s1;
s1.insert(&buf[0]);
s1.insert(&buf[1]);
s1.insert(&buf[2]);
s1.insert(&buf[3]);
EXPECT_EQ(4U, s1.size());
for (int i = 0; i < 8; ++i)
if (i < 4)
EXPECT_TRUE(s1.count(&buf[i]));
else
EXPECT_FALSE(s1.count(&buf[i]));
SmallPtrSet<int *, 4> s2(s1);
EXPECT_EQ(4U, s2.size());
for (int i = 0; i < 8; ++i)
if (i < 4)
EXPECT_TRUE(s2.count(&buf[i]));
else
EXPECT_FALSE(s2.count(&buf[i]));
s1 = s2;
EXPECT_EQ(4U, s1.size());
for (int i = 0; i < 8; ++i)
if (i < 4)
EXPECT_TRUE(s1.count(&buf[i]));
else
EXPECT_FALSE(s1.count(&buf[i]));
SmallPtrSet<int *, 4> s3(llvm_move(s1));
EXPECT_EQ(4U, s3.size());
for (int i = 0; i < 8; ++i)
if (i < 4)
EXPECT_TRUE(s3.count(&buf[i]));
else
EXPECT_FALSE(s3.count(&buf[i]));
s1 = llvm_move(s3);
EXPECT_EQ(4U, s1.size());
for (int i = 0; i < 8; ++i)
if (i < 4)
EXPECT_TRUE(s1.count(&buf[i]));
else
EXPECT_FALSE(s1.count(&buf[i]));
}
TEST(SmallPtrSetTest, SwapTest) {
int buf[10];