BridgedASTType::isEscapable

Author: atrick

include/swift/SIL/SILBridging.h

@@ -195,6 +195,8 @@ struct BridgedASTType {
 
   BRIDGED_INLINE bool isOpenedExistentialWithError() const;
 
+  BRIDGED_INLINE bool isEscapable() const;
+
   // =========================================================================//
   //                              SILFunctionType
   // =========================================================================//

include/swift/SIL/SILBridgingImpl.h

@@ -77,6 +77,10 @@ bool BridgedASTType::isOpenedExistentialWithError() const {
   return unbridged()->isOpenedExistentialWithError();
 }
 
+bool BridgedASTType::isEscapable() const {
+  return unbridged()->isEscapable();
+}
+
 BridgedResultInfoArray
 BridgedASTType::SILFunctionType_getResultsWithError() const {
   return unbridged()->castTo<swift::SILFunctionType>()->getResultsWithError();

lib/SIL/IR/SILType.cpp

@@ -1046,7 +1046,31 @@ SILType::getSingletonAggregateFieldType(SILModule &M,
 }
 
 bool SILType::isEscapable() const {
-  return getASTType()->isEscapable();
+  CanType ty = getASTType();
+
+  // For storage with reference ownership, check the referent.
+  if (auto refStorage = ty->getAs<ReferenceStorageType>())
+    ty = refStorage->getReferentType()->getCanonicalType();
+
+  if (auto fnTy = getAs<SILFunctionType>()) {
+    return !fnTy->isNoEscape();
+  }
+  if (auto boxTy = getAs<SILBoxType>()) {
+    auto fields = boxTy->getLayout()->getFields();
+    assert(fields.size() == 1);
+    ty = fields[0].getLoweredType();
+  }
+
+  // TODO: Support ~Escapable in parameter packs.
+  //
+  // Treat all other SIL-specific types as Escapable.
+  if (isa<SILBlockStorageType,
+          SILBoxType,
+          SILPackType,
+          SILTokenType>(ty)) {
+    return true;
+  }
+  return ty->isEscapable();
 }
 
 bool SILType::isMoveOnly(bool orWrapped) const {