diff --git a/lib/AST/ExprClassification.cpp b/lib/AST/ExprClassification.cpp
index c035a42439a39ed24a28c23e1ad16948a46911d0..d149bdd0cdf9798f4f0b33acc94e7d171091b665 100644
--- a/lib/AST/ExprClassification.cpp
+++ b/lib/AST/ExprClassification.cpp
@@ -190,7 +190,6 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
case Expr::ArrayInitIndexExprClass:
case Expr::NoInitExprClass:
case Expr::DesignatedInitUpdateExprClass:
- case Expr::CoyieldExprClass:
return Cl::CL_PRValue;
// Next come the complicated cases.
@@ -414,7 +413,8 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
return ClassifyInternal(Ctx, cast<InitListExpr>(E)->getInit(0));
case Expr::CoawaitExprClass:
- return ClassifyInternal(Ctx, cast<CoawaitExpr>(E)->getResumeExpr());
+ case Expr::CoyieldExprClass:
+ return ClassifyInternal(Ctx, cast<CoroutineSuspendExpr>(E)->getResumeExpr());
}
llvm_unreachable("unhandled expression kind in classification");
diff --git a/lib/CodeGen/CGCoroutine.cpp b/lib/CodeGen/CGCoroutine.cpp
index bc5f6327c9a055fa8936a40b04d00be295273a56..daefb0edcb4304f92ddd37579f4a4286b328d0c8 100644
--- a/lib/CodeGen/CGCoroutine.cpp
+++ b/lib/CodeGen/CGCoroutine.cpp
@@ -148,10 +148,16 @@ static SmallString<32> buildSuspendPrefixStr(CGCoroData &Coro, AwaitKind Kind) {
//
// See llvm's docs/Coroutines.rst for more details.
//
-static RValue emitSuspendExpression(CodeGenFunction &CGF, CGCoroData &Coro,
+namespace {
+ struct LValueOrRValue {
+ LValue LV;
+ RValue RV;
+ };
+}
+static LValueOrRValue emitSuspendExpression(CodeGenFunction &CGF, CGCoroData &Coro,
CoroutineSuspendExpr const &S,
AwaitKind Kind, AggValueSlot aggSlot,
- bool ignoreResult) {
+ bool ignoreResult, bool forLValue) {
auto *E = S.getCommonExpr();
// FIXME: rsmith 5/22/2017. Does it still make sense for us to have a
@@ -217,7 +223,12 @@ static RValue emitSuspendExpression(CodeGenFunction &CGF, CGCoroData &Coro,
// Emit await_resume expression.
CGF.EmitBlock(ReadyBlock);
- return CGF.EmitAnyExpr(S.getResumeExpr(), aggSlot, ignoreResult);
+ LValueOrRValue Res;
+ if (forLValue)
+ Res.LV = CGF.EmitLValue(S.getResumeExpr());
+ else
+ Res.RV = CGF.EmitAnyExpr(S.getResumeExpr(), aggSlot, ignoreResult);
+ return Res;
}
RValue CodeGenFunction::EmitCoawaitExpr(const CoawaitExpr &E,
@@ -225,13 +236,13 @@ RValue CodeGenFunction::EmitCoawaitExpr(const CoawaitExpr &E,
bool ignoreResult) {
return emitSuspendExpression(*this, *CurCoro.Data, E,
CurCoro.Data->CurrentAwaitKind, aggSlot,
- ignoreResult);
+ ignoreResult, /*forLValue*/false).RV;
}
RValue CodeGenFunction::EmitCoyieldExpr(const CoyieldExpr &E,
AggValueSlot aggSlot,
bool ignoreResult) {
return emitSuspendExpression(*this, *CurCoro.Data, E, AwaitKind::Yield,
- aggSlot, ignoreResult);
+ aggSlot, ignoreResult, /*forLValue*/false).RV;
}
void CodeGenFunction::EmitCoreturnStmt(CoreturnStmt const &S) {
@@ -240,6 +251,38 @@ void CodeGenFunction::EmitCoreturnStmt(CoreturnStmt const &S) {
EmitBranchThroughCleanup(CurCoro.Data->FinalJD);
}
+
+#ifndef NDEBUG
+static QualType getCoroutineSuspendExprReturnType(const ASTContext &Ctx,
+ const CoroutineSuspendExpr *E) {
+ const auto *RE = E->getResumeExpr();
+ // Is it possible for RE to be a CXXBindTemporaryExpr wrapping
+ // a MemberCallExpr?
+ assert(isa<CallExpr>(RE) && "unexpected suspend expression type");
+ return cast<CallExpr>(RE)->getCallReturnType(Ctx);
+}
+#endif
+
+LValue
+CodeGenFunction::EmitCoawaitLValue(const CoawaitExpr *E) {
+ assert(getCoroutineSuspendExprReturnType(getContext(), E)->isReferenceType() &&
+ "Can't have a scalar return unless the return type is a "
+ "reference type!");
+ return emitSuspendExpression(*this, *CurCoro.Data, *E,
+ CurCoro.Data->CurrentAwaitKind, AggValueSlot::ignored(),
+ /*ignoreResult*/false, /*forLValue*/true).LV;
+}
+
+LValue
+CodeGenFunction::EmitCoyieldLValue(const CoyieldExpr *E) {
+ assert(getCoroutineSuspendExprReturnType(getContext(), E)->isReferenceType() &&
+ "Can't have a scalar return unless the return type is a "
+ "reference type!");
+ return emitSuspendExpression(*this, *CurCoro.Data, *E,
+ AwaitKind::Yield, AggValueSlot::ignored(),
+ /*ignoreResult*/false, /*forLValue*/true).LV;
+}
+
// Hunts for the parameter reference in the parameter copy/move declaration.
namespace {
struct GetParamRef : public StmtVisitor<GetParamRef> {
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 1b3103fd71fa7e87a96e1649b075aa9aee696013..15829888ead9c5bb8081075e066896c488b0d8be 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1158,6 +1158,11 @@ LValue CodeGenFunction::EmitLValue(const Expr *E) {
case Expr::MaterializeTemporaryExprClass:
return EmitMaterializeTemporaryExpr(cast<MaterializeTemporaryExpr>(E));
+
+ case Expr::CoawaitExprClass:
+ return EmitCoawaitLValue(cast<CoawaitExpr>(E));
+ case Expr::CoyieldExprClass:
+ return EmitCoyieldLValue(cast<CoyieldExpr>(E));
}
}
diff --git a/lib/CodeGen/CodeGenFunction.h b/lib/CodeGen/CodeGenFunction.h
index a179276a07af1fefd5d51121e2311bc31ea10a35..831eedf9e478056db2e20ed246329bbef96adcc0 100644
--- a/lib/CodeGen/CodeGenFunction.h
+++ b/lib/CodeGen/CodeGenFunction.h
@@ -2550,9 +2550,11 @@ public:
RValue EmitCoawaitExpr(const CoawaitExpr &E,
AggValueSlot aggSlot = AggValueSlot::ignored(),
bool ignoreResult = false);
+ LValue EmitCoawaitLValue(const CoawaitExpr *E);
RValue EmitCoyieldExpr(const CoyieldExpr &E,
AggValueSlot aggSlot = AggValueSlot::ignored(),
bool ignoreResult = false);
+ LValue EmitCoyieldLValue(const CoyieldExpr *E);
RValue EmitCoroutineIntrinsic(const CallExpr *E, unsigned int IID);
void EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock = false);
diff --git a/test/CodeGenCoroutines/coro-await.cpp b/test/CodeGenCoroutines/coro-await.cpp
index 1e2deaa8f59a76b556b604a5657647413acb54de..fc6559f1e0ad4113c14462a48855b05f753985a2 100644
--- a/test/CodeGenCoroutines/coro-await.cpp
+++ b/test/CodeGenCoroutines/coro-await.cpp
@@ -1,4 +1,5 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fcoroutines-ts -std=c++14 -emit-llvm %s -o - -disable-llvm-passes | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -fcoroutines-ts -std=c++14 \
+// RUN: -emit-llvm %s -o - -disable-llvm-passes -Wno-coroutine -Wno-unused | FileCheck %s
namespace std {
namespace experimental {
@@ -278,3 +279,50 @@ void AwaitLValue() {
suspend_always lval;
co_await lval;
}
+
+struct RefTag { };
+
+struct AwaitResumeReturnsLValue {
+ bool await_ready();
+ void await_suspend(std::experimental::coroutine_handle<>);
+ RefTag& await_resume();
+};
+
+
+template<>
+struct std::experimental::coroutine_traits<void,double> {
+ struct promise_type {
+ void get_return_object();
+ init_susp initial_suspend();
+ final_susp final_suspend();
+ void return_void();
+ AwaitResumeReturnsLValue yield_value(int);
+ };
+};
+
+// Verifies that we don't crash when returning an lvalue from an await_resume()
+// expression.
+// CHECK-LABEL: define void @_Z18AwaitReturnsLValued(double)
+void AwaitReturnsLValue(double) {
+ AwaitResumeReturnsLValue a;
+ // CHECK: %[[AVAR:.+]] = alloca %struct.AwaitResumeReturnsLValue,
+ // CHECK: %[[XVAR:.+]] = alloca %struct.RefTag*,
+
+ // CHECK: %[[YVAR:.+]] = alloca %struct.RefTag*,
+ // CHECK-NEXT: %[[TMP1:.+]] = alloca %struct.AwaitResumeReturnsLValue,
+
+ // CHECK: %[[ZVAR:.+]] = alloca %struct.RefTag*,
+ // CHECK-NEXT: %[[TMP2:.+]] = alloca %struct.AwaitResumeReturnsLValue,
+
+ // CHECK: %[[RES1:.+]] = call dereferenceable({{.*}}) %struct.RefTag* @_ZN24AwaitResumeReturnsLValue12await_resumeEv(%struct.AwaitResumeReturnsLValue* %[[AVAR]])
+ // CHECK-NEXT: store %struct.RefTag* %[[RES1]], %struct.RefTag** %[[XVAR]],
+ RefTag& x = co_await a;
+
+ // CHECK: %[[RES2:.+]] = call dereferenceable({{.*}}) %struct.RefTag* @_ZN24AwaitResumeReturnsLValue12await_resumeEv(%struct.AwaitResumeReturnsLValue* %[[TMP1]])
+ // CHECK-NEXT: store %struct.RefTag* %[[RES2]], %struct.RefTag** %[[YVAR]],
+
+ RefTag& y = co_await AwaitResumeReturnsLValue{};
+ // CHECK: %[[RES3:.+]] = call dereferenceable({{.*}}) %struct.RefTag* @_ZN24AwaitResumeReturnsLValue12await_resumeEv(%struct.AwaitResumeReturnsLValue* %[[TMP2]])
+ // CHECK-NEXT: store %struct.RefTag* %[[RES3]], %struct.RefTag** %[[ZVAR]],
+ RefTag& z = co_yield 42;
+}