Do a compiler check that we use one of the types from PointerUnion[N], instead of a runtime check.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127145 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Argyrios Kyrtzidis 2011-03-07 01:30:20 +00:00
parent 19b6c73878
commit 128ccbb8e5

View File

@ -19,16 +19,56 @@
namespace llvm {
/// getPointerUnionTypeNum - If the argument has type PT1* or PT2* return
/// false or true respectively.
/// \brief Statically get an integer for a type. For:
/// @code
/// PointerUnionTypeNum<PT1, PT2>::template NumFor<T>::Result
/// @endcode
/// Result will be 0 if T is PT1, 1 if it is PT2, and -1 otherwise.
template <typename PT1, typename PT2>
static inline int getPointerUnionTypeNum(PT1 *P) { return 0; }
template <typename PT1, typename PT2>
static inline int getPointerUnionTypeNum(PT2 *P) { return 1; }
template <typename PT1, typename PT2>
static inline int getPointerUnionTypeNum(...) { return -1; }
struct PointerUnionTypeNum {
private:
struct IsNeither { char x; };
struct IsPT1 { char x[2]; };
struct IsPT2 { char x[3]; };
static IsPT1 determine(PT1 *P);
static IsPT2 determine(PT2 *P);
static IsNeither determine(...);
public:
template <typename T>
struct NumFor {
static const int Result = (int)sizeof(determine((T*)0)) - 2;
};
};
template <typename T>
struct PointerUnionTypeSelectorReturn {
typedef T Return;
};
/// \brief Get a type based on whether two types are the same or not. For:
/// @code
/// typedef typename PointerUnionTypeSelector<T1, T2, EQ, NE>::Return Ret;
/// @endcode
/// Ret will be EQ type if T1 is same as T2 or NE type otherwise.
template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
struct PointerUnionTypeSelector {
typedef typename PointerUnionTypeSelectorReturn<RET_NE>::Return Return;
};
template <typename T, typename RET_EQ, typename RET_NE>
struct PointerUnionTypeSelector<T, T, RET_EQ, RET_NE> {
typedef typename PointerUnionTypeSelectorReturn<RET_EQ>::Return Return;
};
template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
struct PointerUnionTypeSelectorReturn<
PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE> > {
typedef typename PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>::Return
Return;
};
/// Provide PointerLikeTypeTraits for void* that is used by PointerUnion
/// for the two template arguments.
template <typename PT1, typename PT2>
@ -87,8 +127,10 @@ namespace llvm {
/// is<T>() return true if the Union currently holds the type matching T.
template<typename T>
int is() const {
int TyNo = ::llvm::getPointerUnionTypeNum<PT1, PT2>((T*)0);
assert(TyNo != -1 && "Type query could never succeed on PointerUnion!");
static const int TyNo =
::llvm::PointerUnionTypeNum<PT1, PT2>::template NumFor<T>::Result;
char TYPE_IS_NOT_IN_UNION[TyNo*2+1]; // statically check the type.
(void)TYPE_IS_NOT_IN_UNION;
return static_cast<int>(Val.getInt()) == TyNo;
}
@ -175,6 +217,34 @@ namespace llvm {
typedef PointerUnion<InnerUnion, PT3> ValTy;
private:
ValTy Val;
struct IsInnerUnion {
ValTy Val;
IsInnerUnion(ValTy val) : Val(val) { }
template<typename T>
int is() const {
return Val.template is<InnerUnion>() &&
Val.template get<InnerUnion>().template is<T>();
}
template<typename T>
T get() const {
return Val.template get<InnerUnion>().template get<T>();
}
};
struct IsPT3 {
ValTy Val;
IsPT3(ValTy val) : Val(val) { }
template<typename T>
int is() const {
return Val.template is<T>();
}
template<typename T>
T get() const {
return Val.template get<T>();
}
};
public:
PointerUnion3() {}
@ -196,11 +266,12 @@ namespace llvm {
/// is<T>() return true if the Union currently holds the type matching T.
template<typename T>
int is() const {
// Is it PT1/PT2?
if (::llvm::getPointerUnionTypeNum<PT1, PT2>((T*)0) != -1)
return Val.template is<InnerUnion>() &&
Val.template get<InnerUnion>().template is<T>();
return Val.template is<T>();
// If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
typedef typename
::llvm::PointerUnionTypeSelector<PT1, T, IsInnerUnion,
::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3 >
>::Return Ty;
return Ty(Val).is<T>();
}
/// get<T>() - Return the value of the specified pointer type. If the
@ -208,11 +279,12 @@ namespace llvm {
template<typename T>
T get() const {
assert(is<T>() && "Invalid accessor called");
// Is it PT1/PT2?
if (::llvm::getPointerUnionTypeNum<PT1, PT2>((T*)0) != -1)
return Val.template get<InnerUnion>().template get<T>();
return Val.template get<T>();
// If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
typedef typename
::llvm::PointerUnionTypeSelector<PT1, T, IsInnerUnion,
::llvm::PointerUnionTypeSelector<PT2, T, IsInnerUnion, IsPT3 >
>::Return Ty;
return Ty(Val).get<T>();
}
/// dyn_cast<T>() - If the current value is of the specified pointer type,
@ -302,12 +374,13 @@ namespace llvm {
/// is<T>() return true if the Union currently holds the type matching T.
template<typename T>
int is() const {
// Is it PT1/PT2?
if (::llvm::getPointerUnionTypeNum<PT1, PT2>((T*)0) != -1)
return Val.template is<InnerUnion1>() &&
Val.template get<InnerUnion1>().template is<T>();
return Val.template is<InnerUnion2>() &&
Val.template get<InnerUnion2>().template is<T>();
// If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
typedef typename
::llvm::PointerUnionTypeSelector<PT1, T, InnerUnion1,
::llvm::PointerUnionTypeSelector<PT2, T, InnerUnion1, InnerUnion2 >
>::Return Ty;
return Val.template is<Ty>() &&
Val.template get<Ty>().template is<T>();
}
/// get<T>() - Return the value of the specified pointer type. If the
@ -315,11 +388,12 @@ namespace llvm {
template<typename T>
T get() const {
assert(is<T>() && "Invalid accessor called");
// Is it PT1/PT2?
if (::llvm::getPointerUnionTypeNum<PT1, PT2>((T*)0) != -1)
return Val.template get<InnerUnion1>().template get<T>();
return Val.template get<InnerUnion2>().template get<T>();
// If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
typedef typename
::llvm::PointerUnionTypeSelector<PT1, T, InnerUnion1,
::llvm::PointerUnionTypeSelector<PT2, T, InnerUnion1, InnerUnion2 >
>::Return Ty;
return Val.template get<Ty>().template get<T>();
}
/// dyn_cast<T>() - If the current value is of the specified pointer type,