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263 lines
8.6 KiB
C++
263 lines
8.6 KiB
C++
//===--- ProtocolInfo.h - Abstract protocol witness layout ------*- 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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// This file defines types for representing the abstract layout of a
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// protocol.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_IRGEN_PROTOCOLINFO_H
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#define SWIFT_IRGEN_PROTOCOLINFO_H
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#include "swift/AST/Decl.h"
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#include "swift/IRGen/ValueWitness.h"
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#include "WitnessIndex.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/Support/TrailingObjects.h"
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namespace swift {
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class CanType;
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class Decl;
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class ProtocolConformance;
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class ProtocolDecl;
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namespace irgen {
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class ConformanceInfo; // private to GenProto.cpp
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class IRGenModule;
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class TypeInfo;
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/// A witness to a specific element of a protocol. Every
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/// ProtocolTypeInfo stores one of these for each requirement
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/// introduced by the protocol.
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class WitnessTableEntry {
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public:
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void *MemberOrAssociatedType;
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ProtocolDecl *Protocol;
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WitnessTableEntry(void *member, ProtocolDecl *protocol)
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: MemberOrAssociatedType(member), Protocol(protocol) {}
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public:
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WitnessTableEntry() = default;
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static WitnessTableEntry forOutOfLineBase(ProtocolDecl *proto) {
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assert(proto != nullptr);
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return WitnessTableEntry(nullptr, proto);
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}
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/// Is this a base-protocol entry?
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bool isBase() const { return MemberOrAssociatedType == nullptr; }
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bool matchesBase(ProtocolDecl *proto) const {
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assert(proto != nullptr);
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return MemberOrAssociatedType == nullptr && Protocol == proto;
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}
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/// Given that this is a base-protocol entry, is the table
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/// "out of line"?
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bool isOutOfLineBase() const {
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assert(isBase());
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return true;
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}
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ProtocolDecl *getBase() const {
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assert(isBase());
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return Protocol;
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}
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static WitnessTableEntry forFunction(AbstractFunctionDecl *func) {
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assert(func != nullptr);
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return WitnessTableEntry(func, nullptr);
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}
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bool isFunction() const {
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return Protocol == nullptr &&
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isa<AbstractFunctionDecl>(
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static_cast<Decl*>(MemberOrAssociatedType));
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}
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bool matchesFunction(AbstractFunctionDecl *func) const {
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assert(func != nullptr);
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return MemberOrAssociatedType == func && Protocol == nullptr;
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}
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AbstractFunctionDecl *getFunction() const {
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assert(isFunction());
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return static_cast<AbstractFunctionDecl*>(MemberOrAssociatedType);
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}
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static WitnessTableEntry forAssociatedType(AssociatedTypeDecl *ty) {
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return WitnessTableEntry(ty, nullptr);
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}
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bool isAssociatedType() const {
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return Protocol == nullptr &&
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isa<AssociatedTypeDecl>(
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static_cast<Decl*>(MemberOrAssociatedType));
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}
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bool matchesAssociatedType(AssociatedTypeDecl *assocType) const {
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assert(assocType != nullptr);
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return MemberOrAssociatedType == assocType && Protocol == nullptr;
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}
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AssociatedTypeDecl *getAssociatedType() const {
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assert(isAssociatedType());
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return static_cast<AssociatedTypeDecl*>(MemberOrAssociatedType);
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}
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static WitnessTableEntry forAssociatedConformance(CanType path,
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ProtocolDecl *requirement) {
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assert(path && requirement != nullptr);
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return WitnessTableEntry(path.getPointer(), requirement);
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}
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bool isAssociatedConformance() const {
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return Protocol != nullptr && MemberOrAssociatedType != nullptr;
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}
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bool matchesAssociatedConformance(CanType path,
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ProtocolDecl *requirement) const {
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assert(path && requirement != nullptr);
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return MemberOrAssociatedType == path.getPointer() &&
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Protocol == requirement;
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}
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CanType getAssociatedConformancePath() const {
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assert(isAssociatedConformance());
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return CanType(static_cast<TypeBase *>(MemberOrAssociatedType));
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}
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ProtocolDecl *getAssociatedConformanceRequirement() const {
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assert(isAssociatedConformance());
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return Protocol;
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}
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};
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/// An abstract description of a protocol.
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class ProtocolInfo final :
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private llvm::TrailingObjects<ProtocolInfo, WitnessTableEntry> {
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friend TrailingObjects;
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/// A singly-linked-list of all the protocols that have been laid out.
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const ProtocolInfo *NextConverted;
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friend class TypeConverter;
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/// The number of table entries in this protocol layout.
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unsigned NumTableEntries;
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/// A table of all the conformances we've needed so far for this
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/// protocol. We expect this to be quite small for most protocols.
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mutable llvm::SmallDenseMap<const ProtocolConformance*, ConformanceInfo*, 2>
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Conformances;
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ProtocolInfo(ArrayRef<WitnessTableEntry> table)
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: NumTableEntries(table.size()) {
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std::uninitialized_copy(table.begin(), table.end(),
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getTrailingObjects<WitnessTableEntry>());
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}
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static ProtocolInfo *create(ArrayRef<WitnessTableEntry> table);
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public:
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const ConformanceInfo &getConformance(IRGenModule &IGM,
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ProtocolDecl *protocol,
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const ProtocolConformance *conf) const;
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/// The number of witness slots in a conformance to this protocol;
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/// in other words, the size of the table in words.
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unsigned getNumWitnesses() const {
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return NumTableEntries;
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}
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/// Return all of the entries in this protocol witness table.
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///
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/// The addresses of the entries in this array can be passed to
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/// getBaseWitnessIndex/getNonBaseWitnessIndex, below.
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ArrayRef<WitnessTableEntry> getWitnessEntries() const {
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return {getTrailingObjects<WitnessTableEntry>(), NumTableEntries};
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}
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/// Given the address of a witness entry from this PI for a base protocol
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/// conformance, return its witness index.
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WitnessIndex getBaseWitnessIndex(const WitnessTableEntry *witness) const {
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assert(witness && witness->isBase());
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auto entries = getWitnessEntries();
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assert(entries.begin() <= witness && witness < entries.end() &&
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"argument witness entry does not belong to this ProtocolInfo");
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if (witness->isOutOfLineBase()) {
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return WitnessIndex(witness - entries.begin(), false);
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} else {
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return WitnessIndex(0, true);
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}
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}
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/// Given the address of a witness entry from this PI for a non-base
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/// witness, return its witness index.
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WitnessIndex getNonBaseWitnessIndex(const WitnessTableEntry *witness) const {
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assert(witness && !witness->isBase());
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auto entries = getWitnessEntries();
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assert(entries.begin() <= witness && witness < entries.end());
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return WitnessIndex(witness - entries.begin(), false);
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}
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/// Return the witness index for the protocol conformance pointer
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/// for the given base protocol requirement.
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WitnessIndex getBaseIndex(ProtocolDecl *protocol) const {
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for (auto &witness : getWitnessEntries()) {
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if (witness.matchesBase(protocol))
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return getBaseWitnessIndex(&witness);
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}
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llvm_unreachable("didn't find entry for base");
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}
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/// Return the witness index for the witness function for the given
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/// function requirement.
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WitnessIndex getFunctionIndex(AbstractFunctionDecl *function) const {
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for (auto &witness : getWitnessEntries()) {
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if (witness.matchesFunction(function))
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return getNonBaseWitnessIndex(&witness);
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}
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llvm_unreachable("didn't find entry for function");
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}
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/// Return the witness index for the type metadata access function
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/// for the given associated type.
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WitnessIndex getAssociatedTypeIndex(AssociatedTypeDecl *assocType) const {
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for (auto &witness : getWitnessEntries()) {
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if (witness.matchesAssociatedType(assocType))
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return getNonBaseWitnessIndex(&witness);
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}
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llvm_unreachable("didn't find entry for associated type");
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}
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/// Return the witness index for the protocol witness table access
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/// function for the given associated protocol conformance.
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WitnessIndex getAssociatedConformanceIndex(CanType path,
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ProtocolDecl *requirement) const {
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for (auto &witness : getWitnessEntries()) {
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if (witness.matchesAssociatedConformance(path, requirement))
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return getNonBaseWitnessIndex(&witness);
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}
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llvm_unreachable("didn't find entry for associated conformance");
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}
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~ProtocolInfo();
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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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