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Add TinyPtrVector support for general pointer-like things. 

In particular, make TinyPtrVector<PtrIntPair<T *, 1>> work. Remove all
unnecessary assumptions that the element type has a formal "null"
representation. The important property to maintain is that
default-constructed element type has the same internal representation
as the default-constructed PointerUnion (all zero bits).

Remove the incorrect recursive behavior from
PointerUnion::isNull. This was never generally correct because it only
recursed over the first type parameter. With variadic templates it's
completely unnecessary.

llvm-svn: 369473
This commit is contained in:
Andrew Trick 2019-08-20 23:29:28 +00:00
parent 5a7bba09ac
commit 861b371e13
4 changed files with 100 additions and 35 deletions
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19
llvm/include/llvm/ADT/PointerUnion.h
View File

@ -160,10 +160,11 @@ class PointerUnion
void *, pointer_union_detail::bitsRequired(sizeof...(PTs)), int,
pointer_union_detail::PointerUnionUIntTraits<PTs...>>,
0, PTs...> {
// The first type is special in some ways, but we don't want PointerUnion to
// be a 'template <typename First, typename ...Rest>' because it's much more
// convenient to have a name for the whole pack. So split off the first type
// here.
// The first type is special because we want to directly cast a pointer to a
// default-initialized union to a pointer to the first type. But we don't
// want PointerUnion to be a 'template <typename First, typename ...Rest>'
// because it's much more convenient to have a name for the whole pack. So
// split off the first type here.
using First = typename pointer_union_detail::GetFirstType<PTs...>::type;
using Base = typename PointerUnion::PointerUnionMembers;
@ -175,12 +176,7 @@ public:
/// Test if the pointer held in the union is null, regardless of
/// which type it is.
bool isNull() const {
// Convert from the void* to one of the pointer types, to make sure that
// we recursively strip off low bits if we have a nested PointerUnion.
return !PointerLikeTypeTraits<First>::getFromVoidPointer(
this->Val.getPointer());
}
bool isNull() const { return !this->Val.getPointer(); }
explicit operator bool() const { return !isNull(); }
@ -219,7 +215,8 @@ public:
First *getAddrOfPtr1() {
assert(is<First>() && "Val is not the first pointer");
assert(
get<First>() == this->Val.getPointer() &&
PointerLikeTypeTraits<First>::getAsVoidPointer(get<First>()) ==
this->Val.getPointer() &&
"Can't get the address because PointerLikeTypeTraits changes the ptr");
return const_cast<First *>(
reinterpret_cast<const First *>(this->Val.getAddrOfPointer()));

38
llvm/include/llvm/ADT/TinyPtrVector.h
View File

@ -31,6 +31,10 @@ class TinyPtrVector {
public:
using VecTy = SmallVector<EltTy, 4>;
using value_type = typename VecTy::value_type;
// EltTy must be the first pointer type so that is<EltTy> is true for the
// default-constructed PtrUnion. This allows an empty TinyPtrVector to
// naturally vend a begin/end iterator of type EltTy* without an additional
// check for the empty state.
using PtrUnion = PointerUnion<EltTy, VecTy *>;
private:
@ -96,14 +100,14 @@ public:
if (RHS.Val.template is<EltTy>()) {
V->clear();
V->push_back(RHS.front());
RHS.Val = (EltTy)nullptr;
RHS.Val = EltTy();
return *this;
}
delete V;
}
Val = RHS.Val;
RHS.Val = (EltTy)nullptr;
RHS.Val = EltTy();
return *this;
}
@ -213,9 +217,9 @@ public:
EltTy operator[](unsigned i) const {
assert(!Val.isNull() && "can't index into an empty vector");
if (EltTy V = Val.template dyn_cast<EltTy>()) {
if (Val.template is<EltTy>()) {
assert(i == 0 && "tinyvector index out of range");
return V;
return Val.template get<EltTy>();
}
assert(i < Val.template get<VecTy*>()->size() &&
@ -225,29 +229,29 @@ public:
EltTy front() const {
assert(!empty() && "vector empty");
if (EltTy V = Val.template dyn_cast<EltTy>())
return V;
if (Val.template is<EltTy>())
return Val.template get<EltTy>();
return Val.template get<VecTy*>()->front();
}
EltTy back() const {
assert(!empty() && "vector empty");
if (EltTy V = Val.template dyn_cast<EltTy>())
return V;
if (Val.template is<EltTy>())
return Val.template get<EltTy>();
return Val.template get<VecTy*>()->back();
}
void push_back(EltTy NewVal) {
assert(NewVal && "Can't add a null value");
// If we have nothing, add something.
if (Val.isNull()) {
Val = NewVal;
assert(!Val.isNull() && "Can't add a null value");
return;
}
// If we have a single value, convert to a vector.
if (EltTy V = Val.template dyn_cast<EltTy>()) {
if (Val.template is<EltTy>()) {
EltTy V = Val.template get<EltTy>();
Val = new VecTy();
Val.template get<VecTy*>()->push_back(V);
}
@ -267,7 +271,7 @@ public:
void clear() {
// If we have a single value, convert to empty.
if (Val.template is<EltTy>()) {
Val = (EltTy)nullptr;
Val = EltTy();
} else if (VecTy *Vec = Val.template dyn_cast<VecTy*>()) {
// If we have a vector form, just clear it.
Vec->clear();
@ -282,7 +286,7 @@ public:
// If we have a single value, convert to empty.
if (Val.template is<EltTy>()) {
if (I == begin())
Val = (EltTy)nullptr;
Val = EltTy();
} else if (VecTy *Vec = Val.template dyn_cast<VecTy*>()) {
// multiple items in a vector; just do the erase, there is no
// benefit to collapsing back to a pointer
@ -298,7 +302,7 @@ public:
if (Val.template is<EltTy>()) {
if (S == begin() && S != E)
Val = (EltTy)nullptr;
Val = EltTy();
} else if (VecTy *Vec = Val.template dyn_cast<VecTy*>()) {
return Vec->erase(S, E);
}
@ -313,7 +317,8 @@ public:
return std::prev(end());
}
assert(!Val.isNull() && "Null value with non-end insert iterator.");
if (EltTy V = Val.template dyn_cast<EltTy>()) {
if (Val.template is<EltTy>()) {
EltTy V = Val.template get<EltTy>();
assert(I == begin());
Val = Elt;
push_back(V);
@ -339,7 +344,8 @@ public:
}
Val = new VecTy();
} else if (EltTy V = Val.template dyn_cast<EltTy>()) {
} else if (Val.template is<EltTy>()) {
EltTy V = Val.template get<EltTy>();
Val = new VecTy();
Val.template get<VecTy*>()->push_back(V);
}

53
llvm/unittests/ADT/PointerUnionTest.cpp
View File

@ -13,14 +13,25 @@ using namespace llvm;
namespace {
typedef PointerUnion<int *, float *> PU;
typedef PointerUnion3<int *, float *, long long *> PU3;
typedef PointerUnion4<int *, float *, long long *, double *> PU4;
struct PointerUnionTest : public testing::Test {
float f;
int i;
double d;
long long l;
PU a, b, c, n;
PU3 i3, f3, l3;
PU4 i4, f4, l4, d4;
PU4 i4null, f4null, l4null, d4null;
PointerUnionTest() : f(3.14f), i(42), a(&f), b(&i), c(&i), n() {}
PointerUnionTest()
: f(3.14f), i(42), d(3.14), l(42), a(&f), b(&i), c(&i), n(), i3(&i),
f3(&f), l3(&l), i4(&i), f4(&f), l4(&l), d4(&d), i4null((int *)nullptr),
f4null((float *)nullptr), l4null((long long *)nullptr),
d4null((double *)nullptr) {}
};
TEST_F(PointerUnionTest, Comparison) {
@ -32,6 +43,19 @@ TEST_F(PointerUnionTest, Comparison) {
EXPECT_FALSE(b != c);
EXPECT_TRUE(b != n);
EXPECT_FALSE(b == n);
EXPECT_TRUE(i3 == i3);
EXPECT_FALSE(i3 != i3);
EXPECT_TRUE(i3 != f3);
EXPECT_TRUE(f3 != l3);
EXPECT_TRUE(i4 == i4);
EXPECT_FALSE(i4 != i4);
EXPECT_TRUE(i4 != f4);
EXPECT_TRUE(i4 != l4);
EXPECT_TRUE(f4 != l4);
EXPECT_TRUE(l4 != d4);
EXPECT_TRUE(i4null != f4null);
EXPECT_TRUE(i4null != l4null);
EXPECT_TRUE(i4null != d4null);
}
TEST_F(PointerUnionTest, Null) {
@ -51,6 +75,17 @@ TEST_F(PointerUnionTest, Null) {
b = nullptr;
EXPECT_EQ(n, b);
EXPECT_NE(b, c);
EXPECT_FALSE(i3.isNull());
EXPECT_FALSE(f3.isNull());
EXPECT_FALSE(l3.isNull());
EXPECT_FALSE(i4.isNull());
EXPECT_FALSE(f4.isNull());
EXPECT_FALSE(l4.isNull());
EXPECT_FALSE(d4.isNull());
EXPECT_TRUE(i4null.isNull());
EXPECT_TRUE(f4null.isNull());
EXPECT_TRUE(l4null.isNull());
EXPECT_TRUE(d4null.isNull());
}
TEST_F(PointerUnionTest, Is) {
@ -60,6 +95,17 @@ TEST_F(PointerUnionTest, Is) {
EXPECT_FALSE(b.is<float *>());
EXPECT_TRUE(n.is<int *>());
EXPECT_FALSE(n.is<float *>());
EXPECT_TRUE(i3.is<int *>());
EXPECT_TRUE(f3.is<float *>());
EXPECT_TRUE(l3.is<long long *>());
EXPECT_TRUE(i4.is<int *>());
EXPECT_TRUE(f4.is<float *>());
EXPECT_TRUE(l4.is<long long *>());
EXPECT_TRUE(d4.is<double *>());
EXPECT_TRUE(i4null.is<int *>());
EXPECT_TRUE(f4null.is<float *>());
EXPECT_TRUE(l4null.is<long long *>());
EXPECT_TRUE(d4null.is<double *>());
}
TEST_F(PointerUnionTest, Get) {
@ -105,4 +151,9 @@ TEST_F(PointerUnionTest, ManyElements) {
EXPECT_TRUE(a != PU8(&a0));
}
TEST_F(PointerUnionTest, GetAddrOfPtr1) {
EXPECT_TRUE((void *)b.getAddrOfPtr1() == (void *)&b);
EXPECT_TRUE((void *)n.getAddrOfPtr1() == (void *)&n);
}
} // end anonymous namespace

25
llvm/unittests/ADT/TinyPtrVectorTest.cpp
View File

@ -22,12 +22,21 @@
using namespace llvm;
namespace {
template <typename T> struct RemovePointer : std::remove_pointer<T> {};
template <typename PointerTy, unsigned IntBits, typename IntType,
typename PtrTraits, typename Info>
struct RemovePointer<
PointerIntPair<PointerTy, IntBits, IntType, PtrTraits, Info>> {
typedef typename RemovePointer<PointerTy>::type type;
};
template <typename VectorT>
class TinyPtrVectorTest : public testing::Test {
protected:
typedef typename VectorT::value_type PtrT;
typedef typename std::remove_pointer<PtrT>::type ValueT;
typedef typename RemovePointer<PtrT>::type ValueT;
using PtrTraits = PointerLikeTypeTraits<PtrT>;
VectorT V;
VectorT V2;
@ -37,11 +46,13 @@ protected:
TinyPtrVectorTest() {
for (size_t i = 0, e = array_lengthof(TestValues); i != e; ++i)
TestPtrs.push_back(&TestValues[i]);
TestPtrs.push_back(PtrT(&TestValues[i]));
std::shuffle(TestPtrs.begin(), TestPtrs.end(), std::mt19937{});
}
PtrT makePtr(ValueT *V) { return PtrT(V); }
ArrayRef<PtrT> testArray(size_t N) {
return makeArrayRef(&TestPtrs[0], N);
}
@ -69,9 +80,9 @@ protected:
}
};
typedef ::testing::Types<TinyPtrVector<int*>,
TinyPtrVector<double*>
> TinyPtrVectorTestTypes;
typedef ::testing::Types<TinyPtrVector<int *>, TinyPtrVector<double *>,
TinyPtrVector<PointerIntPair<int *, 1>>>
TinyPtrVectorTestTypes;
TYPED_TEST_CASE(TinyPtrVectorTest, TinyPtrVectorTestTypes);
TYPED_TEST(TinyPtrVectorTest, EmptyTest) {
@ -95,8 +106,8 @@ TYPED_TEST(TinyPtrVectorTest, PushPopBack) {
this->expectValues(this->V, this->testArray(4));
this->V.pop_back();
this->expectValues(this->V, this->testArray(3));
this->TestPtrs[3] = &this->TestValues[42];
this->TestPtrs[4] = &this->TestValues[43];
this->TestPtrs[3] = this->makePtr(&this->TestValues[42]);
this->TestPtrs[4] = this->makePtr(&this->TestValues[43]);
this->V.push_back(this->TestPtrs[3]);
this->expectValues(this->V, this->testArray(4));
this->V.push_back(this->TestPtrs[4]);