[coroutines] Add overloaded unary 'operator co_await'.

llvm-svn: 250991

clang/include/clang/Basic/OperatorKinds.def

@@ -101,6 +101,7 @@ OVERLOADED_OPERATOR_MULTI(Subscript      , "[]"                       , false, t
 // ?: can *not* be overloaded, but we need the overload
 // resolution machinery for it.
 OVERLOADED_OPERATOR_MULTI(Conditional    , "?"                        , false, true , false)
+OVERLOADED_OPERATOR(Coawait              , "co_await", kw_co_await    , true , false, false)
 
 #undef OVERLOADED_OPERATOR_MULTI
 #undef OVERLOADED_OPERATOR

clang/lib/AST/ItaniumMangle.cpp

@@ -1753,6 +1753,9 @@ CXXNameMangler::mangleOperatorName(OverloadedOperatorKind OO, unsigned Arity) {
   // The conditional operator can't be overloaded, but we still handle it when
   // mangling expressions.
   case OO_Conditional: Out << "qu"; break;
+  // Proposal on cxx-abi-dev, 2015-10-21.
+  //              ::= aw        # co_await
+  case OO_Coawait: Out << "aw"; break;
 
   case OO_None:
   case NUM_OVERLOADED_OPERATORS:

clang/lib/AST/MicrosoftMangle.cpp

@@ -1046,6 +1046,14 @@ void MicrosoftCXXNameMangler::mangleOperatorName(OverloadedOperatorKind OO,
     break;
   }
 
+  case OO_Coawait: {
+    DiagnosticsEngine &Diags = Context.getDiags();
+    unsigned DiagID = Diags.getCustomDiagID(DiagnosticsEngine::Error,
+      "cannot mangle this operator co_await yet");
+    Diags.Report(Loc, DiagID);
+    break;
+  }
+
   case OO_None:
   case NUM_OVERLOADED_OPERATORS:
     llvm_unreachable("Not an overloaded operator");

clang/lib/AST/StmtProfile.cpp

@@ -854,6 +854,7 @@ static Stmt::StmtClass DecodeOperatorCall(const CXXOperatorCallExpr *S,
   case OO_Arrow:
   case OO_Call:
   case OO_Conditional:
+  case OO_Coawait:
   case NUM_OVERLOADED_OPERATORS:
     llvm_unreachable("Invalid operator call kind");
       

clang/lib/Sema/SemaOpenMP.cpp

@@ -6385,6 +6385,7 @@ OMPClause *Sema::ActOnOpenMPReductionClause(
   case OO_Call:
   case OO_Subscript:
   case OO_Conditional:
+  case OO_Coawait:
   case NUM_OVERLOADED_OPERATORS:
     llvm_unreachable("Unexpected reduction identifier");
   case OO_None:

clang/lib/Sema/SemaOverload.cpp

@@ -8228,6 +8228,7 @@ void Sema::AddBuiltinOperatorCandidates(OverloadedOperatorKind Op,
   case OO_Array_New:
   case OO_Array_Delete:
   case OO_Call:
+  case OO_Coawait:
     llvm_unreachable(
                     "Special operators don't use AddBuiltinOperatorCandidates");
 

clang/test/Parser/cxx1z-coroutines.cpp

@@ -19,3 +19,17 @@ U f(T t) {
   else
     co_return {t};
 }
+
+struct Y {};
+struct X { Y operator co_await(); };
+struct Z {};
+Y operator co_await(Z);
+
+void f(X x, Z z) {
+  x.operator co_await();
+  operator co_await(z);
+}
+
+void operator co_await(); // expected-error {{must have at least one parameter}}
+void operator co_await(X, Y, Z); // expected-error {{must be a unary operator}}
+void operator co_await(int); // expected-error {{parameter of class or enumeration type}}