[coroutines] Handle get_return_object_on_allocation_failure
Summary:
If promise_type has get_return_object_on_allocation_failure defined,
check if an allocation function returns nullptr, and if so,
return the result of get_return_object_on_allocation_failure().
Reviewers: rsmith, EricWF
Reviewed By: EricWF
Subscribers: mehdi_amini, cfe-commits
Differential Revision: https://reviews.llvm.org/D31399
llvm-svn: 298891
diff --git a/clang/lib/Sema/SemaCoroutine.cpp b/clang/lib/Sema/SemaCoroutine.cpp
index 309194f..d8e7b9b 100644
--- a/clang/lib/Sema/SemaCoroutine.cpp
+++ b/clang/lib/Sema/SemaCoroutine.cpp
@@ -708,8 +708,8 @@
}
this->IsValid = makePromiseStmt() && makeInitialAndFinalSuspend() &&
makeOnException() && makeOnFallthrough() &&
- makeNewAndDeleteExpr() && makeReturnObject() &&
- makeParamMoves();
+ makeReturnOnAllocFailure() && makeNewAndDeleteExpr() &&
+ makeReturnObject() && makeParamMoves();
}
bool isInvalid() const { return !this->IsValid; }
@@ -720,6 +720,7 @@
bool makeOnFallthrough();
bool makeOnException();
bool makeReturnObject();
+ bool makeReturnOnAllocFailure();
bool makeParamMoves();
};
}
@@ -777,6 +778,66 @@
return true;
}
+static bool diagReturnOnAllocFailure(Sema &S, Expr *E,
+ CXXRecordDecl *PromiseRecordDecl,
+ FunctionScopeInfo &Fn) {
+ auto Loc = E->getExprLoc();
+ if (auto *DeclRef = dyn_cast_or_null<DeclRefExpr>(E)) {
+ auto *Decl = DeclRef->getDecl();
+ if (CXXMethodDecl *Method = dyn_cast_or_null<CXXMethodDecl>(Decl)) {
+ if (Method->isStatic())
+ return true;
+ else
+ Loc = Decl->getLocation();
+ }
+ }
+
+ S.Diag(
+ Loc,
+ diag::err_coroutine_promise_get_return_object_on_allocation_failure)
+ << PromiseRecordDecl;
+ S.Diag(Fn.FirstCoroutineStmtLoc, diag::note_declared_coroutine_here)
+ << Fn.getFirstCoroutineStmtKeyword();
+ return false;
+}
+
+bool SubStmtBuilder::makeReturnOnAllocFailure() {
+ if (!PromiseRecordDecl) return true;
+
+ // [dcl.fct.def.coroutine]/8
+ // The unqualified-id get_return_object_on_allocation_failure is looked up in
+ // the scope of class P by class member access lookup (3.4.5). ...
+ // If an allocation function returns nullptr, ... the coroutine return value
+ // is obtained by a call to ... get_return_object_on_allocation_failure().
+
+ DeclarationName DN =
+ S.PP.getIdentifierInfo("get_return_object_on_allocation_failure");
+ LookupResult Found(S, DN, Loc, Sema::LookupMemberName);
+ // Suppress diagnostics when a private member is selected. The same warnings
+ // will be produced again when building the call.
+ Found.suppressDiagnostics();
+ if (!S.LookupQualifiedName(Found, PromiseRecordDecl)) return true;
+
+ CXXScopeSpec SS;
+ ExprResult DeclNameExpr =
+ S.BuildDeclarationNameExpr(SS, Found, /*NeedsADL=*/false);
+ if (DeclNameExpr.isInvalid()) return false;
+
+ if (!diagReturnOnAllocFailure(S, DeclNameExpr.get(), PromiseRecordDecl, Fn))
+ return false;
+
+ ExprResult ReturnObjectOnAllocationFailure =
+ S.ActOnCallExpr(nullptr, DeclNameExpr.get(), Loc, {}, Loc);
+ if (ReturnObjectOnAllocationFailure.isInvalid()) return false;
+
+ StmtResult ReturnStmt = S.ActOnReturnStmt(
+ Loc, ReturnObjectOnAllocationFailure.get(), S.getCurScope());
+ if (ReturnStmt.isInvalid()) return false;
+
+ this->ReturnStmtOnAllocFailure = ReturnStmt.get();
+ return true;
+}
+
bool SubStmtBuilder::makeNewAndDeleteExpr() {
// Form and check allocation and deallocation calls.
QualType PromiseType = Fn.CoroutinePromise->getType();
@@ -786,7 +847,8 @@
if (S.RequireCompleteType(Loc, PromiseType, diag::err_incomplete_type))
return false;
- // FIXME: Add support for get_return_object_on_allocation failure.
+ // FIXME: Add nothrow_t placement arg for global alloc
+ // if ReturnStmtOnAllocFailure != nullptr.
// FIXME: Add support for stateful allocators.
FunctionDecl *OperatorNew = nullptr;