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3ab5b6fa19
We no longer need this for anything, so remove it from metadata altogether. This simplifies logic for emitting type metadata and makes type metadata smaller. We still pass the parent metadata pointer to type constructors; removing that is a separate change.
101 lines
3.0 KiB
C++
101 lines
3.0 KiB
C++
//===--- EnumMetadataVisitor.h - CRTP for enum metadata ---------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// A CRTP class useful for visiting all of the fields in an
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// enum metadata object.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_IRGEN_ENUMMETADATAVISITOR_H
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#define SWIFT_IRGEN_ENUMMETADATAVISITOR_H
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#include "NominalMetadataVisitor.h"
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#include "GenEnum.h"
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namespace swift {
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namespace irgen {
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/// A CRTP class for laying out enum metadata.
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///
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/// This produces an object corresponding to the EnumMetadata type.
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/// It does not itself doing anything special for metadata templates.
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template <class Impl> class EnumMetadataVisitor
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: public NominalMetadataVisitor<Impl> {
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using super = NominalMetadataVisitor<Impl>;
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protected:
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using super::IGM;
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using super::asImpl;
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/// The Enum.
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EnumDecl *const Target;
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EnumMetadataVisitor(IRGenModule &IGM, EnumDecl *target)
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: super(IGM), Target(target) {}
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public:
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void layout() {
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// Metadata header.
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super::layout();
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// EnumMetadata header.
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asImpl().addNominalTypeDescriptor();
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// If changing this layout, you must update the magic number in
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// emitParentMetadataRef.
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// Instantiation-specific.
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// Add fields for generic cases.
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asImpl().addGenericFields(Target, Target->getDeclaredTypeInContext());
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// Reserve a word to cache the payload size if the type has dynamic layout.
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auto &strategy = getEnumImplStrategy(IGM,
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Target->DeclContext::getDeclaredTypeInContext()->getCanonicalType());
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if (strategy.needsPayloadSizeInMetadata())
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asImpl().addPayloadSize();
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}
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};
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/// An "implementation" of EnumMetadataVisitor that just scans through
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/// the metadata layout, maintaining the next index: the offset (in
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/// pointer-sized chunks) into the metadata for the next field.
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template <class Impl>
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class EnumMetadataScanner : public EnumMetadataVisitor<Impl> {
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typedef EnumMetadataVisitor<Impl> super;
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protected:
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Size NextOffset = Size(0);
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EnumMetadataScanner(IRGenModule &IGM, EnumDecl *target)
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: super(IGM, target) {}
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public:
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void addMetadataFlags() { addPointer(); }
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void addValueWitnessTable() { addPointer(); }
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void addNominalTypeDescriptor() { addPointer(); }
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void addGenericArgument(CanType argument) { addPointer(); }
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void addGenericWitnessTable(CanType argument, ProtocolConformanceRef conf) {
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addPointer();
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}
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void addPayloadSize() { addPointer(); }
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private:
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void addPointer() {
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NextOffset += super::IGM.getPointerSize();
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}
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};
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} // end namespace irgen
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} // end namespace swift
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#endif
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