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123 lines
3.5 KiB
C++
123 lines
3.5 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 embeddedLayout() {
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// The embedded layout consists of:
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// + // -1 : vwt
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// + // 0 : metadata flags
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super::layout();
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}
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void layout() {
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static_assert(MetadataAdjustmentIndex::ValueType == 2,
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"Adjustment index must be synchronized with this layout");
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asImpl().addLayoutStringPointer();
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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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// Everything after this is type-specific.
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asImpl().noteStartOfTypeSpecificMembers();
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// Generic arguments.
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// This must always be the first piece of trailing data.
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asImpl().addGenericFields(Target);
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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->getDeclaredTypeInContext()->getCanonicalType());
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if (strategy.needsPayloadSizeInMetadata())
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asImpl().addPayloadSize();
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if (asImpl().hasTrailingFlags())
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asImpl().addTrailingFlags();
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}
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bool hasTrailingFlags() {
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return Target->isGenericContext() &&
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IGM.shouldPrespecializeGenericMetadata();
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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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using super = EnumMetadataVisitor<Impl>;
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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 addLayoutStringPointer() { addPointer(); }
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void addValueWitnessTable() { addPointer(); }
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void addNominalTypeDescriptor() { addPointer(); }
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void addGenericRequirement(GenericRequirement requirement) { addPointer(); }
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void addPayloadSize() { addPointer(); }
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void noteStartOfTypeSpecificMembers() {}
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void addTrailingFlags() { addInt64(); }
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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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void addInt64() { NextOffset += Size(8); }
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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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