[llvm-commits] [llvm] r127145 - /llvm/trunk/include/llvm/ADT/PointerUnion.h
Argyrios Kyrtzidis
akyrtzi at gmail.com
Sun Mar 6 17:30:20 PST 2011
Author: akirtzidis
Date: Sun Mar 6 19:30:20 2011
New Revision: 127145
URL: http://llvm.org/viewvc/llvm-project?rev=127145&view=rev
Log:
Do a compiler check that we use one of the types from PointerUnion[N], instead of a runtime check.
Modified:
llvm/trunk/include/llvm/ADT/PointerUnion.h
Modified: llvm/trunk/include/llvm/ADT/PointerUnion.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/PointerUnion.h?rev=127145&r1=127144&r2=127145&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/PointerUnion.h (original)
+++ llvm/trunk/include/llvm/ADT/PointerUnion.h Sun Mar 6 19:30:20 2011
@@ -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 @@
/// 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 @@
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 @@
/// 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 @@
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 @@
/// 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 @@
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,
More information about the llvm-commits
mailing list