Implement AST, semantics, and CodeGen for C++ pseudo-destructor
expressions, e.g.,

  p->~T()

when p is a pointer to a scalar type. 

We don't currently diagnose errors when pseudo-destructor expressions
are used in any way other than by forming a call.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@81009 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 5c8dfa4..4a8253d 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1234,6 +1234,16 @@
     if (const CXXMethodDecl *MD = dyn_cast_or_null<CXXMethodDecl>(TargetDecl))
       return EmitCXXOperatorMemberCallExpr(CE, MD);
       
+  if (isa<CXXPseudoDestructorExpr>(E->getCallee())) {
+    // C++ [expr.pseudo]p1:
+    //   The result shall only be used as the operand for the function call 
+    //   operator (), and the result of such a call has type void. The only
+    //   effect is the evaluation of the postfix-expression before the dot or
+    //   arrow.
+    EmitScalarExpr(E->getCallee());
+    return RValue::get(0);
+  }
+      
   llvm::Value *Callee = EmitScalarExpr(E->getCallee());
   return EmitCall(Callee, E->getCallee()->getType(),
                   E->arg_begin(), E->arg_end(), TargetDecl);
diff --git a/lib/CodeGen/CGExprScalar.cpp b/lib/CodeGen/CGExprScalar.cpp
index 4496c53..8732dc9 100644
--- a/lib/CodeGen/CGExprScalar.cpp
+++ b/lib/CodeGen/CGExprScalar.cpp
@@ -305,7 +305,17 @@
     CGF.EmitCXXDeleteExpr(E);
     return 0;
   }
-      
+  
+  Value *VisitCXXPseudoDestructorExpr(const CXXPseudoDestructorExpr *E) {
+    // C++ [expr.pseudo]p1:
+    //   The result shall only be used as the operand for the function call 
+    //   operator (), and the result of such a call has type void. The only
+    //   effect is the evaluation of the postfix-expression before the dot or
+    //   arrow.
+    CGF.EmitScalarExpr(E->getBase());
+    return 0;
+  }
+    
   // Binary Operators.
   Value *EmitMul(const BinOpInfo &Ops) {
     if (CGF.getContext().getLangOptions().OverflowChecking