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4444d83756
Officially kick SILBoxType over to be "nominal" in its layout, with generic layouts structurally parameterized only by formal types. Change SIL to lower a capture to a nongeneric box when possible, or a box capturing the enclosing generic context when necessary.
121 lines
4.4 KiB
C++
121 lines
4.4 KiB
C++
//===--- Substitution.cpp - Type substitutions ----------------------------===//
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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 - 2016 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 implements the Substitution class and operations on it.
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//
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//===----------------------------------------------------------------------===//
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#include "swift/AST/Substitution.h"
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#include "swift/AST/ASTContext.h"
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#include "swift/AST/GenericEnvironment.h"
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#include "swift/AST/Module.h"
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#include "swift/AST/SubstitutionMap.h"
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#include "swift/AST/Types.h"
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#include "llvm/ADT/DenseMap.h"
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using namespace swift;
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bool Substitution::operator==(const Substitution &other) const {
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// The archetypes may be missing, but we can compare them directly
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// because archetypes are always canonical.
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return
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Replacement->getCanonicalType() == other.Replacement->getCanonicalType() &&
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Conformance.equals(other.Conformance);
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}
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Substitution::Substitution(Type Replacement,
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ArrayRef<ProtocolConformanceRef> Conformance)
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: Replacement(Replacement), Conformance(Conformance)
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{
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// The replacement type must be materializable.
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assert(Replacement->isMaterializable()
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&& "cannot substitute with a non-materializable type");
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}
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Substitution Substitution::subst(Module *module,
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const SubstitutionMap &subMap) const {
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return subst(module, QueryTypeSubstitutionMap{subMap.getMap()},
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LookUpConformanceInSubstitutionMap(subMap));
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}
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Substitution Substitution::subst(Module *module,
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TypeSubstitutionFn subs,
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LookupConformanceFn conformances) const {
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// Substitute the replacement.
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Type substReplacement = Replacement.subst(subs, conformances, None);
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assert(substReplacement && "substitution replacement failed");
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if (substReplacement->isEqual(Replacement))
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return *this;
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if (Conformance.empty()) {
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return {substReplacement, Conformance};
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}
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bool conformancesChanged = false;
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SmallVector<ProtocolConformanceRef, 4> substConformances;
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substConformances.reserve(Conformance.size());
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for (auto c : Conformance) {
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// If we have a concrete conformance, we need to substitute the
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// conformance to apply to the new type.
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if (c.isConcrete()) {
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auto substC = c.getConcrete()->subst(module, substReplacement,
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subs, conformances);
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substConformances.push_back(ProtocolConformanceRef(substC));
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if (c != substConformances.back())
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conformancesChanged = true;
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continue;
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}
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// Otherwise, we may need to fill in the conformance.
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ProtocolDecl *proto = c.getAbstract();
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Optional<ProtocolConformanceRef> conformance;
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// If the original type was an archetype, check the conformance map.
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if (Replacement->is<SubstitutableType>()
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|| Replacement->is<DependentMemberType>()) {
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conformance = conformances(Replacement->getCanonicalType(),
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substReplacement,
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proto->getDeclaredType());
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}
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// If that didn't find anything, we can still synthesize AnyObject
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// conformances from thin air. FIXME: gross.
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if (!conformance &&
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proto->isSpecificProtocol(KnownProtocolKind::AnyObject)) {
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auto classDecl
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= substReplacement->getClassOrBoundGenericClass();
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assert(classDecl);
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SmallVector<ProtocolConformance *, 1> lookupResults;
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classDecl->lookupConformance(classDecl->getParentModule(),
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proto, lookupResults);
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conformance = ProtocolConformanceRef(lookupResults.front());
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}
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assert(conformance);
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if (conformance->isConcrete())
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conformancesChanged = true;
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substConformances.push_back(*conformance);
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}
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assert(substConformances.size() == Conformance.size());
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ArrayRef<ProtocolConformanceRef> substConfs;
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if (conformancesChanged)
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substConfs = Replacement->getASTContext().AllocateCopy(substConformances);
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else
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substConfs = Conformance;
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return Substitution{substReplacement, substConfs};
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}
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