Swift SIL: add APIs for box types

Author: eeckstein

SwiftCompilerSources/Sources/SIL/Type.swift

@@ -59,6 +59,8 @@ public struct Type : TypeProperties, CustomStringConvertible, NoReflectionChildr
     return bridged.isReferenceCounted(function.bridged)
   }
 
+  public var isBox: Bool { bridged.isBox() }
+
   public var isMoveOnly: Bool { bridged.isMoveOnly() }
 
   /// Return true if this type conforms to Escapable.
@@ -125,6 +127,11 @@ public struct Type : TypeProperties, CustomStringConvertible, NoReflectionChildr
     return TupleElementArray(type: self)
   }
 
+  public func getBoxFields(in function: Function) -> BoxFieldsArray {
+    precondition(isBox)
+    return BoxFieldsArray(type: self, function: function)
+  }
+
   /// Returns nil if the nominal is a resilient type because in this case the complete list
   /// of fields is not known.
   public func getNominalFields(in function: Function) -> NominalFieldsArray? {
@@ -267,6 +274,18 @@ public struct TupleElementArray : RandomAccessCollection, FormattedLikeArray {
   }
 }
 
+public struct BoxFieldsArray : RandomAccessCollection, FormattedLikeArray {
+  fileprivate let type: Type
+  fileprivate let function: Function
+
+  public var startIndex: Int { return 0 }
+  public var endIndex: Int { Int(type.bridged.getNumBoxFields()) }
+
+  public subscript(_ index: Int) -> Type {
+    type.bridged.getBoxFieldType(index, function.bridged).type
+  }
+}
+
 extension Type: DiagnosticArgument {
   public func _withBridgedDiagnosticArgument(_ fn: (BridgedDiagnosticArgument) -> Void) {
     rawType._withBridgedDiagnosticArgument(fn)

include/swift/SIL/SILBridging.h

@@ -252,6 +252,7 @@ struct BridgedType {
   BRIDGED_INLINE bool isNonTrivialOrContainsRawPointer(BridgedFunction f) const;
   BRIDGED_INLINE bool isLoadable(BridgedFunction f) const;
   BRIDGED_INLINE bool isReferenceCounted(BridgedFunction f) const;
+  BRIDGED_INLINE bool isBox() const;
   BRIDGED_INLINE bool containsNoEscapeFunction() const;
   BRIDGED_INLINE bool isEmpty(BridgedFunction f) const;
   BRIDGED_INLINE bool isMoveOnly() const;
@@ -260,6 +261,8 @@ struct BridgedType {
   BRIDGED_INLINE bool isMarkedAsImmortal() const;
   BRIDGED_INLINE bool isAddressableForDeps(BridgedFunction f) const;
   BRIDGED_INLINE SwiftInt getCaseIdxOfEnumType(BridgedStringRef name) const;
+  BRIDGED_INLINE SwiftInt getNumBoxFields() const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getBoxFieldType(SwiftInt idx, BridgedFunction f) const;
   BRIDGED_INLINE SwiftInt getNumNominalFields() const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getFieldType(SwiftInt idx, BridgedFunction f) const;
   BRIDGED_INLINE SwiftInt getFieldIdxOfNominalType(BridgedStringRef name) const;

include/swift/SIL/SILBridgingImpl.h

@@ -347,6 +347,10 @@ bool BridgedType::isReferenceCounted(BridgedFunction f) const {
   return unbridged().isReferenceCounted(f.getFunction());
 }
 
+bool BridgedType::isBox() const {
+  return unbridged().is<swift::SILBoxType>();
+}
+
 bool BridgedType::containsNoEscapeFunction() const {
   return unbridged().containsNoEscapeFunction();
 }
@@ -379,6 +383,16 @@ SwiftInt BridgedType::getCaseIdxOfEnumType(BridgedStringRef name) const {
   return unbridged().getCaseIdxOfEnumType(name.unbridged());
 }
 
+SwiftInt BridgedType::getNumBoxFields() const {
+  return unbridged().castTo<swift::SILBoxType>()->getLayout()->getFields().size();
+}
+
+BridgedType BridgedType::getBoxFieldType(SwiftInt idx, BridgedFunction f) const {
+  auto *fn = f.getFunction();
+  return swift::getSILBoxFieldType(fn->getTypeExpansionContext(), unbridged().castTo<swift::SILBoxType>(),
+                                   fn->getModule().Types, idx);
+}
+
 SwiftInt BridgedType::getNumNominalFields() const {
   return unbridged().getNumNominalFields();
 }