Revert r144273. It causes clang self-host build failure.

llvm-svn: 144296
diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index ca936f0..25c7a90 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -1029,9 +1029,8 @@
 }
 
 /// Evaluate a function call.
-static bool HandleFunctionCall(const LValue *This, ArrayRef<const Expr*> Args,
-                               const Stmt *Body, EvalInfo &Info,
-                               CCValue &Result) {
+static bool HandleFunctionCall(ArrayRef<const Expr*> Args, const Stmt *Body,
+                               EvalInfo &Info, CCValue &Result) {
   // FIXME: Implement a proper call limit, along with a command-line flag.
   if (Info.NumCalls >= 1000000 || Info.CallStackDepth >= 512)
     return false;
@@ -1040,15 +1039,16 @@
   if (!EvaluateArgs(Args, ArgValues, Info))
     return false;
 
+  // FIXME: Pass in 'this' for member functions.
+  const LValue *This = 0;
   CallStackFrame Frame(Info, This, ArgValues.data());
   return EvaluateStmt(Result, Info, Body) == ESR_Returned;
 }
 
 /// Evaluate a constructor call.
-static bool HandleConstructorCall(const LValue &This,
-                                  ArrayRef<const Expr*> Args,
+static bool HandleConstructorCall(ArrayRef<const Expr*> Args,
                                   const CXXConstructorDecl *Definition,
-                                  EvalInfo &Info,
+                                  EvalInfo &Info, const LValue &This,
                                   APValue &Result) {
   if (Info.NumCalls >= 1000000 || Info.CallStackDepth >= 512)
     return false;
@@ -1305,64 +1305,39 @@
     const Expr *Callee = E->getCallee();
     QualType CalleeType = Callee->getType();
 
+    // FIXME: Handle the case where Callee is a (parenthesized) MemberExpr for a
+    // non-static member function.
+    if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember))
+      return DerivedError(E);
+
+    if (!CalleeType->isFunctionType() && !CalleeType->isFunctionPointerType())
+      return DerivedError(E);
+
+    CCValue Call;
+    if (!Evaluate(Call, Info, Callee) || !Call.isLValue() ||
+        !Call.getLValueBase() || !Call.getLValueOffset().isZero())
+      return DerivedError(Callee);
+
     const FunctionDecl *FD = 0;
-    LValue *This = 0, ThisVal;
-    llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs());
-
-    // Extract function decl and 'this' pointer from the callee.
-    if (CalleeType->isSpecificBuiltinType(BuiltinType::BoundMember)) {
-      const MemberExpr *ME = dyn_cast<MemberExpr>(Callee->IgnoreParens());
-      // FIXME: Handle a BinaryOperator callee ('.*' or '->*').
-      if (!ME)
-        return DerivedError(Callee);
-      if (ME->isArrow()) {
-        if (!EvaluatePointer(ME->getBase(), ThisVal, Info))
-          return DerivedError(ME);
-      } else {
-        if (!EvaluateLValue(ME->getBase(), ThisVal, Info))
-          return DerivedError(ME);
-      }
-      This = &ThisVal;
+    if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Call.getLValueBase()))
+      FD = dyn_cast<FunctionDecl>(DRE->getDecl());
+    else if (const MemberExpr *ME = dyn_cast<MemberExpr>(Call.getLValueBase()))
       FD = dyn_cast<FunctionDecl>(ME->getMemberDecl());
-      if (!FD)
-        return DerivedError(ME);
-    } else if (CalleeType->isFunctionPointerType()) {
-      CCValue Call;
-      if (!Evaluate(Call, Info, Callee) || !Call.isLValue() ||
-          !Call.getLValueBase() || !Call.getLValueOffset().isZero())
-        return DerivedError(Callee);
+    if (!FD)
+      return DerivedError(Callee);
 
-      const Expr *Base = Call.getLValueBase();
-
-      if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Base))
-        FD = dyn_cast<FunctionDecl>(DRE->getDecl());
-      else if (const MemberExpr *ME = dyn_cast<MemberExpr>(Base))
-        FD = dyn_cast<FunctionDecl>(ME->getMemberDecl());
-      if (!FD)
-        return DerivedError(Callee);
-
-      // Overloaded operator calls to member functions are represented as normal
-      // calls with 'this' as the first argument.
-      const CXXMethodDecl *MD = dyn_cast<CXXMethodDecl>(FD);
-      if (MD && !MD->isStatic()) {
-        if (!EvaluateLValue(Args[0], ThisVal, Info))
-          return DerivedError(Args[0]);
-        This = &ThisVal;
-        Args = Args.slice(1);
-      }
-
-      // Don't call function pointers which have been cast to some other type.
-      if (!Info.Ctx.hasSameType(CalleeType->getPointeeType(), FD->getType()))
-        return DerivedError(E);
-    }
+    // Don't call function pointers which have been cast to some other type.
+    if (!Info.Ctx.hasSameType(CalleeType->getPointeeType(), FD->getType()))
+      return DerivedError(E);
 
     const FunctionDecl *Definition;
     Stmt *Body = FD->getBody(Definition);
     CCValue CCResult;
     APValue Result;
+    llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs());
 
     if (Body && Definition->isConstexpr() && !Definition->isInvalidDecl() &&
-        HandleFunctionCall(This, Args, Body, Info, CCResult) &&
+        HandleFunctionCall(Args, Body, Info, CCResult) &&
         CheckConstantExpression(CCResult, Result))
       return DerivedSuccess(CCValue(Result, CCValue::GlobalValue()), E);
 
@@ -1915,8 +1890,8 @@
       return Visit(ME->GetTemporaryExpr());
 
   llvm::ArrayRef<const Expr*> Args(E->getArgs(), E->getNumArgs());
-  return HandleConstructorCall(This, Args, cast<CXXConstructorDecl>(Definition),
-                               Info, Result);
+  return HandleConstructorCall(Args, cast<CXXConstructorDecl>(Definition),
+                               Info, This, Result);
 }
 
 static bool EvaluateRecord(const Expr *E, const LValue &This,