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//===--- RequirementMachine.h - Generics with term rewriting ----*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2021 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
//
//===----------------------------------------------------------------------===//
#ifndef SWIFT_REQUIREMENTMACHINE_H
#define SWIFT_REQUIREMENTMACHINE_H
#include "swift/AST/GenericSignature.h"
#include "swift/AST/RequirementSignature.h"
#include "llvm/ADT/DenseMap.h"
#include <vector>
#include "Diagnostics.h"
#include "PropertyMap.h"
#include "RewriteContext.h"
#include "RewriteSystem.h"
namespace llvm {
class raw_ostream;
}
namespace swift {
class AbstractGenericSignatureRequest;
class ASTContext;
class AssociatedTypeDecl;
class CanType;
class GenericTypeParamType;
class InferredGenericSignatureRequest;
class LayoutConstraint;
class ProtocolDecl;
class Requirement;
class RequirementSignatureRequest;
class Type;
class UnifiedStatsReporter;
namespace rewriting {
class RewriteContext;
/// Wraps a rewrite system with higher-level operations in terms of
/// generic signatures and interface types.
class RequirementMachine final {
friend class swift::ASTContext;
friend class swift::rewriting::RewriteContext;
friend class swift::RequirementSignatureRequest;
friend class swift::AbstractGenericSignatureRequest;
friend class swift::InferredGenericSignatureRequest;
GenericSignature Sig;
SmallVector<GenericTypeParamType *, 2> Params;
RewriteContext &Context;
RewriteSystem System;
PropertyMap Map;
bool Dump = false;
bool Complete = false;
/// Parameters to prevent runaway completion and property map construction.
unsigned MaxRuleCount;
unsigned MaxRuleLength;
unsigned MaxConcreteNesting;
UnifiedStatsReporter *Stats;
/// All conformance paths computed so far.
llvm::DenseMap<std::pair<Term, ProtocolDecl *>,
ConformancePath> ConformancePaths;
/// Conformance access paths computed during the last round. All elements
/// have the same length. If a conformance access path of greater length
/// is requested, we refill CurrentConformancePaths with all paths of
/// length N+1, and add them to the ConformancePaths map.
std::vector<std::pair<Term, ConformancePath>> CurrentConformancePaths;
explicit RequirementMachine(RewriteContext &rewriteCtx);
RequirementMachine(const RequirementMachine &) = delete;
RequirementMachine(RequirementMachine &&) = delete;
RequirementMachine &operator=(const RequirementMachine &) = delete;
RequirementMachine &operator=(RequirementMachine &&) = delete;
void checkCompletionResult(CompletionResult result) const;
std::pair<CompletionResult, unsigned>
initWithProtocolSignatureRequirements(
ArrayRef<const ProtocolDecl *> protos);
std::pair<CompletionResult, unsigned>
initWithGenericSignature(GenericSignature sig);
std::pair<CompletionResult, unsigned>
initWithProtocolWrittenRequirements(
ArrayRef<const ProtocolDecl *> component,
const llvm::DenseMap<const ProtocolDecl *,
SmallVector<StructuralRequirement, 4>> protos);
std::pair<CompletionResult, unsigned>
initWithWrittenRequirements(
ArrayRef<GenericTypeParamType *> genericParams,
ArrayRef<StructuralRequirement> requirements);
bool isComplete() const;
std::pair<CompletionResult, unsigned>
computeCompletion(RewriteSystem::ValidityPolicy policy);
void freeze();
void computeRequirementDiagnostics(
SmallVectorImpl<RequirementError> &errors,
ArrayRef<InverseRequirement> inverses,
SourceLoc signatureLoc);
MutableTerm getLongestValidPrefix(const MutableTerm &term) const;
void buildRequirementsFromRules(
ArrayRef<unsigned> requirementRules,
ArrayRef<unsigned> typeAliasRules,
ArrayRef<GenericTypeParamType *> genericParams,
bool reconstituteSugar,
std::vector<Requirement> &reqs,
std::vector<ProtocolTypeAlias> &aliases) const;
ArrayRef<GenericTypeParamType *> getGenericParams() const {
return Params;
}
public:
~RequirementMachine();
// Generic signature queries. Generally you shouldn't have to construct a
// RequirementMachine instance; instead, call the corresponding methods on
// GenericSignature, which lazily create a RequirementMachine for you.
GenericSignature::LocalRequirements getLocalRequirements(Type depType,
ArrayRef<GenericTypeParamType *> genericParams) const;
bool requiresClass(Type depType) const;
LayoutConstraint getLayoutConstraint(Type depType) const;
bool requiresProtocol(Type depType, const ProtocolDecl *proto) const;
GenericSignature::RequiredProtocols getRequiredProtocols(Type depType) const;
Type getSuperclassBound(Type depType,
ArrayRef<GenericTypeParamType *> genericParams) const;
bool isConcreteType(Type depType,
const ProtocolDecl *proto=nullptr) const;
Type getConcreteType(Type depType,
ArrayRef<GenericTypeParamType *> genericParams,
const ProtocolDecl *proto=nullptr) const;
bool areReducedTypeParametersEqual(Type depType1, Type depType2) const;
bool isReducedType(Type type) const;
Type getReducedType(Type type,
ArrayRef<GenericTypeParamType *> genericParams) const;
bool isValidTypeParameter(Type type) const;
ConformancePath getConformancePath(Type type, ProtocolDecl *protocol);
TypeDecl *lookupNestedType(Type depType, Identifier name) const;
private:
MutableTerm getReducedShapeTerm(Type type) const;
public:
Type getReducedShape(Type type,
ArrayRef<GenericTypeParamType *> genericParams) const;
bool haveSameShape(Type type1, Type type2) const;
llvm::DenseMap<const ProtocolDecl *, RequirementSignature>
computeMinimalProtocolRequirements();
GenericSignature
computeMinimalGenericSignature(bool reconstituteSugar);
ArrayRef<Rule> getLocalRules() const;
std::string getRuleAsStringForDiagnostics(unsigned ruleID) const;
GenericSignatureErrors getErrors() const;
void verify(const MutableTerm &term) const;
void dump(llvm::raw_ostream &out) const;
DebugOptions getDebugOptions() const { return Context.getDebugOptions(); }
};
} // end namespace rewriting
} // end namespace swift
#endif
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