Add member template 'Type::getAs<T>', which converts a Type* to a respective T*.
This method is intended to eventually replace the individual
Type::getAsXXXType<> methods.

The motivation behind this change is twofold:

1) Reduce redundant implementations of Type::getAsXXXType() methods. Most of
them are basically copy-and-paste.

2) By centralizing the implementation of the getAs<Type> logic we can more
smoothly move over to Doug Gregor's proposed canonical type smart pointer
scheme.

Along with this patch:

a) Removed 'Type::getAsPointerType()'; now clients use getAs<PointerType>.
b) Removed 'Type::getAsBlockPointerTypE()'; now clients use getAs<BlockPointerType>.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@76098 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index 4eed018..6256872 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -205,7 +205,7 @@
       bool HasVAListArg = Format->getFirstArg() == 0;
       if (!HasVAListArg) {
         const FunctionType *FT = 
-          Ty->getAsBlockPointerType()->getPointeeType()->getAsFunctionType();
+          Ty->getAs<BlockPointerType>()->getPointeeType()->getAsFunctionType();
         if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT))
           HasVAListArg = !Proto->isVariadic();
       }
@@ -241,7 +241,7 @@
     return Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer)
              << FirstArg->getType() << FirstArg->getSourceRange();
   
-  QualType ValType = FirstArg->getType()->getAsPointerType()->getPointeeType();
+  QualType ValType = FirstArg->getType()->getAs<PointerType>()->getPointeeType();
   if (!ValType->isIntegerType() && !ValType->isPointerType() && 
       !ValType->isBlockPointerType())
     return Diag(DRE->getLocStart(),
@@ -344,7 +344,7 @@
                                            TUScope, false, DRE->getLocStart()));
   const FunctionProtoType *BuiltinFT =
     NewBuiltinDecl->getType()->getAsFunctionProtoType();
-  ValType = BuiltinFT->getArgType(0)->getAsPointerType()->getPointeeType();
+  ValType = BuiltinFT->getArgType(0)->getAs<PointerType>()->getPointeeType();
   
   // If the first type needs to be converted (e.g. void** -> int*), do it now.
   if (BuiltinFT->getArgType(0) != FirstArg->getType()) {
@@ -750,7 +750,7 @@
       if (const ArrayType *AT = Context.getAsArrayType(T)) {
         isConstant = AT->getElementType().isConstant(Context);
       }
-      else if (const PointerType *PT = T->getAsPointerType()) {
+      else if (const PointerType *PT = T->getAs<PointerType>()) {
         isConstant = T.isConstant(Context) && 
                      PT->getPointeeType().isConstant(Context);
       }