| //===--- StructMetadataVisitor.h - CRTP for struct metadata ------*- C++ -*-===// |
| // |
| // This source file is part of the Swift.org open source project |
| // |
| // Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors |
| // Licensed under Apache License v2.0 with Runtime Library Exception |
| // |
| // See https://swift.org/LICENSE.txt for license information |
| // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // A CRTP class useful for laying out struct metadata. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef SWIFT_IRGEN_STRUCTMETADATALAYOUT_H |
| #define SWIFT_IRGEN_STRUCTMETADATALAYOUT_H |
| |
| #include "NominalMetadataVisitor.h" |
| |
| namespace swift { |
| namespace irgen { |
| |
| /// A CRTP class for laying out struct metadata. |
| /// |
| /// This produces an object corresponding to the StructMetadata type. |
| /// It does not itself doing anything special for metadata templates. |
| template <class Impl> class StructMetadataVisitor |
| : public NominalMetadataVisitor<Impl> { |
| using super = NominalMetadataVisitor<Impl>; |
| |
| protected: |
| using super::IGM; |
| using super::asImpl; |
| |
| /// The struct. |
| StructDecl *const Target; |
| |
| StructMetadataVisitor(IRGenModule &IGM, StructDecl *target) |
| : super(IGM), Target(target) {} |
| |
| public: |
| void layout() { |
| // Metadata header. |
| super::layout(); |
| |
| // StructMetadata header. |
| asImpl().addNominalTypeDescriptor(); |
| |
| // Everything after this is type-specific. |
| asImpl().noteStartOfTypeSpecificMembers(); |
| |
| // Generic arguments. |
| // This must always be the first piece of trailing data. |
| asImpl().addGenericFields(Target, Target->getDeclaredTypeInContext()); |
| |
| // Struct field offsets. |
| asImpl().noteStartOfFieldOffsets(); |
| for (VarDecl *prop : Target->getStoredProperties()) |
| asImpl().addFieldOffset(prop); |
| |
| asImpl().noteEndOfFieldOffsets(); |
| } |
| |
| // Note the start of the field offset vector. |
| void noteStartOfFieldOffsets() {} |
| |
| // Note the end of the field offset vector. |
| void noteEndOfFieldOffsets() {} |
| }; |
| |
| /// An "implementation" of StructMetadataVisitor that just scans through |
| /// the metadata layout, maintaining the offset of the next field. |
| template <class Impl> |
| class StructMetadataScanner : public StructMetadataVisitor<Impl> { |
| using super = StructMetadataVisitor<Impl>; |
| |
| protected: |
| Size NextOffset = Size(0); |
| |
| StructMetadataScanner(IRGenModule &IGM, StructDecl *target) |
| : super(IGM, target) {} |
| |
| public: |
| void addMetadataFlags() { addPointer(); } |
| void addValueWitnessTable() { addPointer(); } |
| void addNominalTypeDescriptor() { addPointer(); } |
| void addFieldOffset(VarDecl *) { addInt32(); } |
| void addGenericArgument(CanType argument) { addPointer(); } |
| void addGenericWitnessTable(CanType argument, ProtocolConformanceRef conf) { |
| addPointer(); |
| } |
| void noteStartOfTypeSpecificMembers() {} |
| |
| void noteEndOfFieldOffsets() { |
| NextOffset = NextOffset.roundUpToAlignment(super::IGM.getPointerAlignment()); |
| } |
| |
| private: |
| void addPointer() { |
| NextOffset += super::IGM.getPointerSize(); |
| } |
| void addInt32() { NextOffset += Size(4); } |
| }; |
| |
| } // end namespace irgen |
| } // end namespace swift |
| |
| #endif |