1 files changed, 76 insertions, 8 deletions

diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index 6dcb705c44d3..fe77c7f6f3bf 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -4543,6 +4543,12 @@ public:
                              Call.getLValueBase().dyn_cast<const ValueDecl*>());
       if (!FD)
         return Error(Callee);
+      // Don't call function pointers which have been cast to some other type.
+      // Per DR (no number yet), the caller and callee can differ in noexcept.
+      if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
+        CalleeType->getPointeeType(), FD->getType())) {
+        return Error(E);
+      }
 
       // Overloaded operator calls to member functions are represented as normal
       // calls with '*this' as the first argument.
@@ -4558,14 +4564,42 @@ public:
           return false;
         This = &ThisVal;
         Args = Args.slice(1);
+      } else if (MD && MD->isLambdaStaticInvoker()) {   
+        // Map the static invoker for the lambda back to the call operator.
+        // Conveniently, we don't have to slice out the 'this' argument (as is
+        // being done for the non-static case), since a static member function
+        // doesn't have an implicit argument passed in.
+        const CXXRecordDecl *ClosureClass = MD->getParent();
+        assert(
+            ClosureClass->captures_begin() == ClosureClass->captures_end() &&
+            "Number of captures must be zero for conversion to function-ptr");
+
+        const CXXMethodDecl *LambdaCallOp =
+            ClosureClass->getLambdaCallOperator();
+
+        // Set 'FD', the function that will be called below, to the call
+        // operator.  If the closure object represents a generic lambda, find
+        // the corresponding specialization of the call operator.
+
+        if (ClosureClass->isGenericLambda()) {
+          assert(MD->isFunctionTemplateSpecialization() &&
+                 "A generic lambda's static-invoker function must be a "
+                 "template specialization");
+          const TemplateArgumentList *TAL = MD->getTemplateSpecializationArgs();
+          FunctionTemplateDecl *CallOpTemplate =
+              LambdaCallOp->getDescribedFunctionTemplate();
+          void *InsertPos = nullptr;
+          FunctionDecl *CorrespondingCallOpSpecialization =
+              CallOpTemplate->findSpecialization(TAL->asArray(), InsertPos);
+          assert(CorrespondingCallOpSpecialization &&
+                 "We must always have a function call operator specialization "
+                 "that corresponds to our static invoker specialization");
+          FD = cast<CXXMethodDecl>(CorrespondingCallOpSpecialization);
+        } else
+          FD = LambdaCallOp;
       }
 
-      // Don't call function pointers which have been cast to some other type.
-      // Per DR (no number yet), the caller and callee can differ in noexcept.
-      if (!Info.Ctx.hasSameFunctionTypeIgnoringExceptionSpec(
-              CalleeType->getPointeeType(), FD->getType())) {
-        return Error(E);
-      }
+      
     } else
       return Error(E);
 
@@ -5834,6 +5868,7 @@ namespace {
     bool VisitCXXConstructExpr(const CXXConstructExpr *E) {
       return VisitCXXConstructExpr(E, E->getType());
     }
+    bool VisitLambdaExpr(const LambdaExpr *E);
     bool VisitCXXInheritedCtorInitExpr(const CXXInheritedCtorInitExpr *E);
     bool VisitCXXConstructExpr(const CXXConstructExpr *E, QualType T);
     bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E);
@@ -6168,6 +6203,21 @@ bool RecordExprEvaluator::VisitCXXStdInitializerListExpr(
   return true;
 }
 
+bool RecordExprEvaluator::VisitLambdaExpr(const LambdaExpr *E) {
+  const CXXRecordDecl *ClosureClass = E->getLambdaClass();
+  if (ClosureClass->isInvalidDecl()) return false;
+
+  if (Info.checkingPotentialConstantExpression()) return true;
+  if (E->capture_size()) {
+    Info.FFDiag(E, diag::note_unimplemented_constexpr_lambda_feature_ast)
+        << "can not evaluate lambda expressions with captures";
+    return false;
+  }
+  // FIXME: Implement captures.
+  Result = APValue(APValue::UninitStruct(), /*NumBases*/0, /*NumFields*/0);
+  return true;
+}
+
 static bool EvaluateRecord(const Expr *E, const LValue &This,
                            APValue &Result, EvalInfo &Info) {
   assert(E->isRValue() && E->getType()->isRecordType() &&
@@ -6217,6 +6267,9 @@ public:
   bool VisitCXXStdInitializerListExpr(const CXXStdInitializerListExpr *E) {
     return VisitConstructExpr(E);
   }
+  bool VisitLambdaExpr(const LambdaExpr *E) {
+    return VisitConstructExpr(E);
+  }
 };
 } // end anonymous namespace
 
@@ -10357,10 +10410,25 @@ bool Expr::isCXX11ConstantExpr(const ASTContext &Ctx, APValue *Result,
 
 bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
                                     const FunctionDecl *Callee,
-                                    ArrayRef<const Expr*> Args) const {
+                                    ArrayRef<const Expr*> Args,
+                                    const Expr *This) const {
   Expr::EvalStatus Status;
   EvalInfo Info(Ctx, Status, EvalInfo::EM_ConstantExpressionUnevaluated);
 
+  LValue ThisVal;
+  const LValue *ThisPtr = nullptr;
+  if (This) {
+#ifndef NDEBUG
+    auto *MD = dyn_cast<CXXMethodDecl>(Callee);
+    assert(MD && "Don't provide `this` for non-methods.");
+    assert(!MD->isStatic() && "Don't provide `this` for static methods.");
+#endif
+    if (EvaluateObjectArgument(Info, This, ThisVal))
+      ThisPtr = &ThisVal;
+    if (Info.EvalStatus.HasSideEffects)
+      return false;
+  }
+
   ArgVector ArgValues(Args.size());
   for (ArrayRef<const Expr*>::iterator I = Args.begin(), E = Args.end();
        I != E; ++I) {
@@ -10373,7 +10441,7 @@ bool Expr::EvaluateWithSubstitution(APValue &Value, ASTContext &Ctx,
   }
 
   // Build fake call to Callee.
-  CallStackFrame Frame(Info, Callee->getLocation(), Callee, /*This*/nullptr,
+  CallStackFrame Frame(Info, Callee->getLocation(), Callee, ThisPtr,
                        ArgValues.data());
   return Evaluate(Value, Info, this) && !Info.EvalStatus.HasSideEffects;
 }