SIL: add AST.Type.loweredType and CanonicalType.loweredType

Author: eeckstein

SwiftCompilerSources/Sources/SIL/ASTExtensions.swift

@@ -13,12 +13,29 @@
 import AST
 import SILBridging
 
+extension AST.`Type` {
+  // See `CanonicalType.loweredType(in:)`.
+  public func loweredType(in function: Function, maximallyAbstracted: Bool = false) -> Type {
+    function.bridged.getLoweredType(bridged, maximallyAbstracted).type.objectType
+  }
+}
+
 extension CanonicalType {
   // This can yield nil if the AST type is not a lowered type.
   // For example, if the AST type is a `AnyFunctionType` for which the lowered type would be a `SILFunctionType`.
   public var silType: Type? {
     BridgedType.createSILType(bridged).typeOrNil
   }
+
+  // Lowers the AST type to a SIL type - in a specific function.
+  // In contrast to `silType` this always succeeds. Still, it's not allowed to do this for certain AST types
+  // which are not present in SIL, like an `InOut` or LValue types.
+  //
+  // If `maximallyAbstracted` is true, the lowering is done with a completely opaque abstraction pattern
+  // (see AbstractionPattern for details).
+  public func loweredType(in function: Function, maximallyAbstracted: Bool = false) -> Type {
+    type.loweredType(in: function, maximallyAbstracted: maximallyAbstracted)
+  }
 }
 
 extension Decl {

include/swift/SIL/SILBridging.h

@@ -528,7 +528,7 @@ struct BridgedFunction {
   BRIDGED_INLINE void setNeedStackProtection(bool needSP) const;
   BRIDGED_INLINE void setIsPerformanceConstraint(bool isPerfConstraint) const;
   BRIDGED_INLINE bool isResilientNominalDecl(BridgedDeclObj decl) const;
-  BRIDGED_INLINE BridgedType getLoweredType(BridgedASTType type) const;
+  SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getLoweredType(BridgedASTType type, bool maximallyAbstracted) const;
   SWIFT_IMPORT_UNSAFE BRIDGED_INLINE BridgedType getLoweredType(BridgedType type) const;
   BRIDGED_INLINE BridgedLinkage getLinkage() const;
   BRIDGED_INLINE void setLinkage(BridgedLinkage linkage) const;

include/swift/SIL/SILBridgingImpl.h

@@ -912,7 +912,10 @@ bool BridgedFunction::isResilientNominalDecl(BridgedDeclObj decl) const {
                                                            getFunction()->getResilienceExpansion());
 }
 
-BridgedType BridgedFunction::getLoweredType(BridgedASTType type) const {
+BridgedType BridgedFunction::getLoweredType(BridgedASTType type, bool maximallyAbstracted) const {
+  if (maximallyAbstracted) {
+    return BridgedType(getFunction()->getLoweredType(swift::Lowering::AbstractionPattern::getOpaque(), type.type));
+  }
   return BridgedType(getFunction()->getLoweredType(type.type));
 }