From 0179e977234fef45b1877eb93a3c7565cdd1862d Mon Sep 17 00:00:00 2001
From: Douglas Gregor <dgregor@apple.com>
Date: Tue, 30 Mar 2010 18:05:52 +0000
Subject: [PATCH] Switch isa_impl from a function template to a class template
 with a static inline member function doit(). This enables the use of partial
 specialization to override the last stage of the "isa" check.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99898 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Support/Casting.h | 20 +++++---
 include/llvm/Type.h            |  8 +--
 include/llvm/Value.h           | 94 ++++++++++++++++++++++------------
 3 files changed, 78 insertions(+), 44 deletions(-)

diff --git a/include/llvm/Support/Casting.h b/include/llvm/Support/Casting.h
index 17bcb599059..dccbfadfa30 100644
--- a/include/llvm/Support/Casting.h
+++ b/include/llvm/Support/Casting.h
@@ -50,9 +50,11 @@ template<typename From> struct simplify_type<const From> {
 //  if (isa<Type*>(myVal)) { ... }
 //
 template <typename To, typename From>
-inline bool isa_impl(const From &Val) {
-  return To::classof(&Val);
-}
+struct isa_impl {
+  static inline bool doit(const From &Val) {
+    return To::classof(&Val);
+  }
+};
 
 template<typename To, typename From, typename SimpleType>
 struct isa_impl_wrap {
@@ -68,7 +70,7 @@ template<typename To, typename FromTy>
 struct isa_impl_wrap<To, const FromTy, const FromTy> {
   // When From == SimpleType, we are as simple as we are going to get.
   static bool doit(const FromTy &Val) {
-    return isa_impl<To,FromTy>(Val);
+    return isa_impl<To,FromTy>::doit(Val);
   }
 };
 
@@ -251,10 +253,12 @@ struct foo {
     }*/
 };
 
-template <> inline bool isa_impl<foo,bar>(const bar &Val) {
-  dbgs() << "Classof: " << &Val << "\n";
-  return true;
-}
+template <> struct isa_impl<foo,bar> {
+  static inline bool doit(const bar &Val) {
+    dbgs() << "Classof: " << &Val << "\n";
+    return true;
+  }
+};
 
 
 bar *fub();
diff --git a/include/llvm/Type.h b/include/llvm/Type.h
index d09913a1df3..df3a16c5926 100644
--- a/include/llvm/Type.h
+++ b/include/llvm/Type.h
@@ -548,9 +548,11 @@ template <> struct GraphTraits<const Type*> {
   }
 };
 
-template <> inline bool isa_impl<PointerType, Type>(const Type &Ty) {
-  return Ty.getTypeID() == Type::PointerTyID;
-}
+template <> struct isa_impl<PointerType, Type> {
+  static inline bool doit(const Type &Ty) {
+    return Ty.getTypeID() == Type::PointerTyID;
+  }
+};
 
 raw_ostream &operator<<(raw_ostream &OS, const Type &T);
 
diff --git a/include/llvm/Value.h b/include/llvm/Value.h
index 992a90c479c..bc25a0f4014 100644
--- a/include/llvm/Value.h
+++ b/include/llvm/Value.h
@@ -324,39 +324,67 @@ void Use::set(Value *V) {
 // isa - Provide some specializations of isa so that we don't have to include
 // the subtype header files to test to see if the value is a subclass...
 //
-template <> inline bool isa_impl<Constant, Value>(const Value &Val) {
-  return Val.getValueID() >= Value::ConstantFirstVal &&
-         Val.getValueID() <= Value::ConstantLastVal;
-}
-template <> inline bool isa_impl<Argument, Value>(const Value &Val) {
-  return Val.getValueID() == Value::ArgumentVal;
-}
-template <> inline bool isa_impl<InlineAsm, Value>(const Value &Val) {
-  return Val.getValueID() == Value::InlineAsmVal;
-}
-template <> inline bool isa_impl<Instruction, Value>(const Value &Val) {
-  return Val.getValueID() >= Value::InstructionVal;
-}
-template <> inline bool isa_impl<BasicBlock, Value>(const Value &Val) {
-  return Val.getValueID() == Value::BasicBlockVal;
-}
-template <> inline bool isa_impl<Function, Value>(const Value &Val) {
-  return Val.getValueID() == Value::FunctionVal;
-}
-template <> inline bool isa_impl<GlobalVariable, Value>(const Value &Val) {
-  return Val.getValueID() == Value::GlobalVariableVal;
-}
-template <> inline bool isa_impl<GlobalAlias, Value>(const Value &Val) {
-  return Val.getValueID() == Value::GlobalAliasVal;
-}
-template <> inline bool isa_impl<GlobalValue, Value>(const Value &Val) {
-  return isa<GlobalVariable>(Val) || isa<Function>(Val) ||
-         isa<GlobalAlias>(Val);
-}
-template <> inline bool isa_impl<MDNode, Value>(const Value &Val) {
-  return Val.getValueID() == Value::MDNodeVal;
-}
-  
+template <> struct isa_impl<Constant, Value> {
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() >= Value::ConstantFirstVal &&
+      Val.getValueID() <= Value::ConstantLastVal;
+  }
+};
+
+template <> struct isa_impl<Argument, Value> {
+  static inline bool doit (const Value &Val) {
+    return Val.getValueID() == Value::ArgumentVal;
+  }
+};
+
+template <> struct isa_impl<InlineAsm, Value> { 
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() == Value::InlineAsmVal;
+  }
+};
+
+template <> struct isa_impl<Instruction, Value> { 
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() >= Value::InstructionVal;
+  }
+};
+
+template <> struct isa_impl<BasicBlock, Value> { 
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() == Value::BasicBlockVal;
+  }
+};
+
+template <> struct isa_impl<Function, Value> { 
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() == Value::FunctionVal;
+  }
+};
+
+template <> struct isa_impl<GlobalVariable, Value> { 
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() == Value::GlobalVariableVal;
+  }
+};
+
+template <> struct isa_impl<GlobalAlias, Value> { 
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() == Value::GlobalAliasVal;
+  }
+};
+
+template <> struct isa_impl<GlobalValue, Value> { 
+  static inline bool doit(const Value &Val) {
+    return isa<GlobalVariable>(Val) || isa<Function>(Val) ||
+      isa<GlobalAlias>(Val);
+  }
+};
+
+template <> struct isa_impl<MDNode, Value> { 
+  static inline bool doit(const Value &Val) {
+    return Val.getValueID() == Value::MDNodeVal;
+  }
+};
   
 // Value* is only 4-byte aligned.
 template<>
-- 
2.34.1