SwiftCompilerSources: bridge isNoEscape and mayEscape.

Author: atrick

SwiftCompilerSources/Sources/SIL/Type.swift

@@ -58,12 +58,14 @@ public struct Type : CustomStringConvertible, NoReflectionChildren {
   public var isMetatype: Bool { bridged.isMetatype() }
   public var isNoEscapeFunction: Bool { bridged.isNoEscapeFunction() }
   public var isAsyncFunction: Bool { bridged.isAsyncFunction() }
-  public var isEscapable: Bool { bridged.isEscapable() }
 
   public var canBeClass: BridgedType.TraitResult { bridged.canBeClass() }
 
   public var isMoveOnly: Bool { bridged.isMoveOnly() }
 
+  public var isEscapable: Bool { bridged.isEscapable() }
+  public var mayEscape: Bool { !isNoEscapeFunction && isEscapable }
+
   /// Can only be used if the type is in fact a nominal type (`isNominal` is true).
   public var nominal: NominalTypeDecl {
     NominalTypeDecl(_bridged: bridged.getNominalOrBoundGenericNominal())

include/swift/AST/Types.h

@@ -657,6 +657,9 @@ class alignas(1 << TypeAlignInBits) TypeBase
   /// Returns true if this contextual type satisfies a conformance to Escapable.
   bool isEscapable();
 
+  /// Returns true if this contextual type is (Escapable && !isNoEscape).
+  bool mayEscape() { return !isNoEscape() && isEscapable(); }
+
   /// Does the type have outer parenthesis?
   bool hasParenSugar() const { return getKind() == TypeKind::Paren; }
 

include/swift/SIL/SILBridging.h

@@ -243,6 +243,10 @@ struct BridgedASTType {
 
   BRIDGED_INLINE bool isEscapable() const;
 
+  BRIDGED_INLINE bool isNoEscape() const;
+
+  inline bool mayEscape() const { return !isNoEscape() && isEscapable(); }
+
   // =========================================================================//
   //                              SILFunctionType
   // =========================================================================//

include/swift/SIL/SILBridgingImpl.h

@@ -93,6 +93,10 @@ bool BridgedASTType::isEscapable() const {
   return unbridged()->isEscapable();
 }
 
+bool BridgedASTType::isNoEscape() const {
+  return unbridged()->isNoEscape();
+}
+
 BridgedResultInfoArray
 BridgedASTType::SILFunctionType_getResultsWithError() const {
   return unbridged()->castTo<swift::SILFunctionType>()->getResultsWithError();

include/swift/SIL/SILType.h

@@ -899,6 +899,12 @@ class SILType {
   /// lifetime dependence.
   bool isEscapable() const;
 
+  /// True for (isEscapable && !isNoEscapeFunction)
+  ///
+  /// Equivalent to getASTType()->mayEscape(), but handles SIL-specific types,
+  /// namely SILFunctionType.
+  bool mayEscape() const { return !isNoEscapeFunction() && isEscapable(); }
+
   //
   // Accessors for types used in SIL instructions:
   //

lib/SIL/IR/SILType.cpp

@@ -1053,7 +1053,8 @@ bool SILType::isEscapable() const {
     ty = refStorage->getReferentType()->getCanonicalType();
 
   if (auto fnTy = getAs<SILFunctionType>()) {
-    return !fnTy->isNoEscape();
+    // Use isNoEscape instead to determine whether a function type may escape.
+    return true;
   }
   if (auto boxTy = getAs<SILBoxType>()) {
     auto fields = boxTy->getLayout()->getFields();