Create a new expression class, CXXThisExpr, to handle the C++ 'this' primary expression. Remove CXXThis from PredefinedExpr

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@58695 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 85129b4..171f7db 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -417,9 +417,7 @@
   case ObjCPropertyRefExprClass: // FIXME: check if read-only property.
     return LV_Valid;
   case PredefinedExprClass:
-    return (cast<PredefinedExpr>(this)->getIdentType()
-               == PredefinedExpr::CXXThis
-            ? LV_InvalidExpression : LV_Valid);
+    return LV_Valid;
   case VAArgExprClass:
     return LV_Valid;
   case CXXDefaultArgExprClass:
@@ -439,6 +437,8 @@
     if (cast<ExplicitCastExpr>(this)->getTypeAsWritten()->isReferenceType())
       return LV_Valid;
     break;
+  case CXXThisExprClass:
+    return LV_InvalidExpression;
   default:
     break;
   }
diff --git a/lib/AST/ExprCXX.cpp b/lib/AST/ExprCXX.cpp
index 82626d8..0eead3c 100644
--- a/lib/AST/ExprCXX.cpp
+++ b/lib/AST/ExprCXX.cpp
@@ -33,6 +33,10 @@
   return child_iterator();
 }
 
+// CXXThisExpr
+Stmt::child_iterator CXXThisExpr::child_begin() { return child_iterator(); }
+Stmt::child_iterator CXXThisExpr::child_end() { return child_iterator(); }
+
 // CXXThrowExpr
 Stmt::child_iterator CXXThrowExpr::child_begin() { return &Op; }
 Stmt::child_iterator CXXThrowExpr::child_end() {
diff --git a/lib/AST/StmtPrinter.cpp b/lib/AST/StmtPrinter.cpp
index 51f4f51..34aefc2 100644
--- a/lib/AST/StmtPrinter.cpp
+++ b/lib/AST/StmtPrinter.cpp
@@ -839,6 +839,10 @@
   OS << (Node->getValue() ? "true" : "false");
 }
 
+void StmtPrinter::VisitCXXThisExpr(CXXThisExpr *Node) {
+  OS << "this";
+}
+
 void StmtPrinter::VisitCXXThrowExpr(CXXThrowExpr *Node) {
   if (Node->getSubExpr() == 0)
     OS << "throw";
diff --git a/lib/AST/StmtSerialization.cpp b/lib/AST/StmtSerialization.cpp
index 5f87b68..aefaee3 100644
--- a/lib/AST/StmtSerialization.cpp
+++ b/lib/AST/StmtSerialization.cpp
@@ -212,7 +212,10 @@
 
     case CXXConstCastExprClass:
       return CXXConstCastExpr::CreateImpl(D, C, SC);
-      
+
+    case CXXThisExprClass:
+      return CXXThisExpr::CreateImpl(D, C);
+
     case CXXZeroInitValueExprClass:
       return CXXZeroInitValueExpr::CreateImpl(D, C);
   }
@@ -1329,6 +1332,17 @@
   }
 }
 
+void CXXThisExpr::EmitImpl(llvm::Serializer& S) const {
+  S.Emit(getType());
+  S.Emit(Loc);
+}
+
+CXXThisExpr* CXXThisExpr::CreateImpl(llvm::Deserializer& D, ASTContext&) {
+  QualType Ty = QualType::ReadVal(D);
+  SourceLocation Loc = SourceLocation::ReadVal(D);
+  return new CXXThisExpr(Loc, Ty);
+}
+
 void CXXZeroInitValueExpr::EmitImpl(Serializer& S) const {
   S.Emit(getType());
   S.Emit(TyBeginLoc);
diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 33fc52b..e4321f5 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -46,7 +46,7 @@
 
     bool VisitExpr(Expr *Node);
     bool VisitDeclRefExpr(DeclRefExpr *DRE);
-    bool VisitPredefinedExpr(PredefinedExpr *PE);
+    bool VisitCXXThisExpr(CXXThisExpr *ThisE);
   };
 
   /// VisitExpr - Visit all of the children of this expression.
@@ -88,18 +88,14 @@
     return false;
   }
 
-  /// VisitPredefinedExpr - Visit a predefined expression, which could
-  /// refer to "this".
-  bool CheckDefaultArgumentVisitor::VisitPredefinedExpr(PredefinedExpr *PE) {
-    if (PE->getIdentType() == PredefinedExpr::CXXThis) {
-      // C++ [dcl.fct.default]p8:
-      //   The keyword this shall not be used in a default argument of a
-      //   member function.
-      return S->Diag(PE->getSourceRange().getBegin(),
-                     diag::err_param_default_argument_references_this,
-                     PE->getSourceRange());
-    }
-    return false;
+  /// VisitCXXThisExpr - Visit a C++ "this" expression.
+  bool CheckDefaultArgumentVisitor::VisitCXXThisExpr(CXXThisExpr *ThisE) {
+    // C++ [dcl.fct.default]p8:
+    //   The keyword this shall not be used in a default argument of a
+    //   member function.
+    return S->Diag(ThisE->getSourceRange().getBegin(),
+                   diag::err_param_default_argument_references_this,
+                   ThisE->getSourceRange());
   }
 }
 
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index fde2852..d012473 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -708,8 +708,7 @@
 
   if (CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(CurContext))
     if (MD->isInstance())
-      return new PredefinedExpr(ThisLoc, MD->getThisType(Context),
-                                PredefinedExpr::CXXThis);
+      return new CXXThisExpr(ThisLoc, MD->getThisType(Context));
 
   return Diag(ThisLoc, diag::err_invalid_this_use);
 }