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c70a5a5d67
More detail: some members are intended to have the same the access as their containing types. This doesn't fly for SE-0025 'private', which would limit the members to only being accessed from lexically within the type decl, instead anywhere the type itself can be seen. Instead, follow the rule for user-written members---internal by default---and then raise the access level to 'public' if necessary. This affects: - enum cases - deinitializers - protocol requirements - generic parameters - implicit initializers - inherited initializers - derived conformance members - synthesized typealiases for associated types
478 lines
18 KiB
C++
478 lines
18 KiB
C++
//===--- DerivedConformanceEquatableHashable.cpp - Derived Equatable & co -===//
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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 http://swift.org/LICENSE.txt for license information
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// See http://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 implicit derivation of the Equatable and Hashable
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// protocols. (Comparable is similar enough in spirit that it would make
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// sense to live here too when we implement its derivation.)
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//
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//===----------------------------------------------------------------------===//
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#include "TypeChecker.h"
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#include "swift/AST/ArchetypeBuilder.h"
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#include "swift/AST/Decl.h"
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#include "swift/AST/Stmt.h"
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#include "swift/AST/Expr.h"
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#include "swift/AST/Types.h"
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#include "llvm/ADT/APInt.h"
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#include "llvm/ADT/SmallString.h"
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#include "llvm/Support/raw_ostream.h"
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#include "DerivedConformances.h"
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using namespace swift;
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using namespace DerivedConformance;
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/// Common preconditions for Equatable and Hashable.
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static bool canDeriveConformance(NominalTypeDecl *type) {
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// The type must be an enum.
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// TODO: Structs with Equatable/Hashable/Comparable members
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auto enumDecl = dyn_cast<EnumDecl>(type);
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if (!enumDecl)
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return false;
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// The enum must not have associated values.
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// TODO: Enums with Equatable/Hashable/Comparable payloads
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if (!enumDecl->hasOnlyCasesWithoutAssociatedValues())
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return false;
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return true;
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}
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/// Create AST statements which convert from an enum to an Int with a switch.
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/// \p stmts The generated statements are appended to this vector.
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/// \p parentDC Either an extension or the enum itself.
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/// \p enumDecl The enum declaration.
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/// \p enumVarDecl The enum input variable.
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/// \p funcDecl The parent function.
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/// \p indexName The name of the output variable.
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/// \return A DeclRefExpr of the output variable (of type Int).
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static DeclRefExpr *convertEnumToIndex(SmallVectorImpl<ASTNode> &stmts,
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DeclContext *parentDC,
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EnumDecl *enumDecl,
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VarDecl *enumVarDecl,
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AbstractFunctionDecl *funcDecl,
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const char *indexName) {
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ASTContext &C = enumDecl->getASTContext();
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Type enumType = enumVarDecl->getType();
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Type intType = C.getIntDecl()->getDeclaredType();
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auto indexVar = new (C) VarDecl(/*static*/false, /*let*/false,
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SourceLoc(), C.getIdentifier(indexName),
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intType, funcDecl);
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indexVar->setImplicit();
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// generate: var indexVar
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Pattern *indexPat = new (C) NamedPattern(indexVar, /*implicit*/ true);
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indexPat->setType(intType);
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indexPat = new (C) TypedPattern(indexPat, TypeLoc::withoutLoc(intType));
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indexPat->setType(intType);
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auto indexBind = PatternBindingDecl::create(C, SourceLoc(),
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StaticSpellingKind::None,
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SourceLoc(),
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indexPat, nullptr, funcDecl);
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unsigned index = 0;
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SmallVector<CaseStmt*, 4> cases;
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for (auto elt : enumDecl->getAllElements()) {
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// generate: case .<Case>:
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auto pat = new (C) EnumElementPattern(TypeLoc::withoutLoc(enumType),
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SourceLoc(), SourceLoc(),
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Identifier(), elt, nullptr);
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pat->setImplicit();
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auto labelItem = CaseLabelItem(/*IsDefault=*/false, pat, SourceLoc(),
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nullptr);
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// generate: indexVar = <index>
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llvm::SmallString<8> indexVal;
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APInt(32, index++).toString(indexVal, 10, /*signed*/ false);
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auto indexStr = C.AllocateCopy(indexVal);
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auto indexExpr = new (C) IntegerLiteralExpr(StringRef(indexStr.data(),
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indexStr.size()), SourceLoc(),
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/*implicit*/ true);
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auto indexRef = new (C) DeclRefExpr(indexVar, DeclNameLoc(),
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/*implicit*/true);
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auto assignExpr = new (C) AssignExpr(indexRef, SourceLoc(),
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indexExpr, /*implicit*/ true);
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auto body = BraceStmt::create(C, SourceLoc(), ASTNode(assignExpr),
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SourceLoc());
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cases.push_back(CaseStmt::create(C, SourceLoc(), labelItem,
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/*HasBoundDecls=*/false,
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SourceLoc(), body));
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}
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// generate: switch enumVar { }
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auto enumRef = new (C) DeclRefExpr(enumVarDecl, DeclNameLoc(),
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/*implicit*/true);
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auto switchStmt = SwitchStmt::create(LabeledStmtInfo(), SourceLoc(), enumRef,
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SourceLoc(), cases, SourceLoc(), C);
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stmts.push_back(indexBind);
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stmts.push_back(switchStmt);
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return new (C) DeclRefExpr(indexVar, DeclNameLoc(), /*implicit*/ true,
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AccessSemantics::Ordinary, intType);
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}
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/// Derive the body for an '==' operator for an enum
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static void deriveBodyEquatable_enum_eq(AbstractFunctionDecl *eqDecl) {
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auto parentDC = eqDecl->getDeclContext();
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ASTContext &C = parentDC->getASTContext();
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auto args = eqDecl->getParameterLists().back();
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auto aParam = args->get(0);
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auto bParam = args->get(1);
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CanType boolTy = C.getBoolDecl()->getDeclaredType().getCanonicalTypeOrNull();
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auto enumDecl = cast<EnumDecl>(aParam->getType()->getAnyNominal());
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// Generate the conversion from the enums to integer indices.
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SmallVector<ASTNode, 6> statements;
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DeclRefExpr *aIndex = convertEnumToIndex(statements, parentDC, enumDecl,
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aParam, eqDecl, "index_a");
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DeclRefExpr *bIndex = convertEnumToIndex(statements, parentDC, enumDecl,
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bParam, eqDecl, "index_b");
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// Generate the compare of the indices.
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FuncDecl *cmpFunc = C.getEqualIntDecl(nullptr);
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assert(cmpFunc && "should have a == for int as we already checked for it");
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auto fnType = dyn_cast<FunctionType>(cmpFunc->getType()->getCanonicalType());
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auto tType = fnType.getInput();
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TupleExpr *abTuple = TupleExpr::create(C, SourceLoc(), { aIndex, bIndex },
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{ }, { }, SourceLoc(),
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/*HasTrailingClosure*/ false,
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/*Implicit*/ true, tType);
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auto *cmpFuncExpr = new (C) DeclRefExpr(cmpFunc, DeclNameLoc(),
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/*implicit*/ true,
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AccessSemantics::Ordinary,
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cmpFunc->getType());
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auto *cmpExpr = new (C) BinaryExpr(cmpFuncExpr, abTuple, /*implicit*/ true,
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boolTy);
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statements.push_back(new (C) ReturnStmt(SourceLoc(), cmpExpr));
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BraceStmt *body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
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eqDecl->setBody(body);
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}
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/// Derive an '==' operator implementation for an enum.
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static ValueDecl *
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deriveEquatable_enum_eq(TypeChecker &tc, Decl *parentDecl, EnumDecl *enumDecl) {
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// enum SomeEnum<T...> {
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// case A, B, C
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//
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// @derived
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// func ==(a: SomeEnum<T...>, b: SomeEnum<T...>) -> Bool {
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// var index_a: Int
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// switch a {
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// case .A: index_a = 0
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// case .B: index_a = 1
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// case .C: index_a = 2
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// }
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// var index_b: Int
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// switch b {
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// case .A: index_b = 0
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// case .B: index_b = 1
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// case .C: index_b = 2
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// }
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// return index_a == index_b
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// }
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ASTContext &C = tc.Context;
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auto parentDC = cast<DeclContext>(parentDecl);
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auto enumTy = parentDC->getDeclaredTypeInContext();
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auto getParamDecl = [&](StringRef s) -> ParamDecl* {
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return new (C) ParamDecl(/*isLet*/true, SourceLoc(), SourceLoc(),
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Identifier(), SourceLoc(), C.getIdentifier(s),
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enumTy, parentDC);
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};
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auto selfDecl = ParamDecl::createUnboundSelf(SourceLoc(), parentDC);
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ParameterList *params[] = {
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ParameterList::createWithoutLoc(selfDecl),
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ParameterList::create(C, {
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getParamDecl("a"),
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getParamDecl("b")
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})
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};
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auto boolTy = C.getBoolDecl()->getDeclaredType();
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DeclName name(C, C.Id_EqualsOperator, params[1]);
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auto eqDecl =
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FuncDecl::create(C, /*StaticLoc=*/SourceLoc(),
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StaticSpellingKind::KeywordStatic,
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/*FuncLoc=*/SourceLoc(), name, /*NameLoc=*/SourceLoc(),
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/*Throws=*/false, /*ThrowsLoc=*/SourceLoc(),
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/*AccessorKeywordLoc=*/SourceLoc(),
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/*GenericParams=*/nullptr,
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params, Type(),
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TypeLoc::withoutLoc(boolTy),
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parentDC);
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eqDecl->setImplicit();
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eqDecl->getAttrs().add(new (C) InfixAttr(/*implicit*/false));
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auto op = C.getStdlibModule()->lookupInfixOperator(C.Id_EqualsOperator);
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if (!op) {
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tc.diagnose(parentDecl->getLoc(),
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diag::broken_equatable_eq_operator);
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return nullptr;
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}
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if (!C.getEqualIntDecl(nullptr)) {
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tc.diagnose(parentDecl->getLoc(), diag::no_equal_overload_for_int);
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return nullptr;
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}
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// Fill in the 'self' type.
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Type selfTy = eqDecl->computeSelfType();
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selfDecl->overwriteType(selfTy);
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eqDecl->setOperatorDecl(op);
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eqDecl->setBodySynthesizer(&deriveBodyEquatable_enum_eq);
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// Compute the type.
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GenericParamList *genericParams = eqDecl->getGenericParamsOfContext();
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Type paramsTy = params[1]->getType(tc.Context);
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Type fnTy = FunctionType::get(paramsTy, boolTy);
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if (genericParams)
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fnTy = PolymorphicFunctionType::get(selfTy, fnTy, genericParams);
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else
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fnTy = FunctionType::get(selfTy, fnTy);
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eqDecl->setType(fnTy);
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// Compute the interface type.
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Type interfaceTy;
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Type selfIfaceTy = eqDecl->computeInterfaceSelfType(false);
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if (auto genericSig = parentDC->getGenericSignatureOfContext()) {
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eqDecl->setGenericSignature(genericSig);
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Type enumIfaceTy = parentDC->getDeclaredInterfaceType();
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TupleTypeElt ifaceParamElts[] = {
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enumIfaceTy, enumIfaceTy,
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};
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auto ifaceParamsTy = TupleType::get(ifaceParamElts, C);
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interfaceTy = FunctionType::get(ifaceParamsTy, boolTy,
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AnyFunctionType::ExtInfo());
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interfaceTy = GenericFunctionType::get(genericSig, selfIfaceTy, interfaceTy,
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AnyFunctionType::ExtInfo());
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} else {
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interfaceTy = FunctionType::get(paramsTy, boolTy);
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interfaceTy = FunctionType::get(selfIfaceTy, interfaceTy);
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}
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eqDecl->setInterfaceType(interfaceTy);
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// Since we can't insert the == operator into the same FileUnit as the enum,
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// itself, we have to give it at least internal access.
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eqDecl->setAccessibility(std::max(enumDecl->getFormalAccess(),
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Accessibility::Internal));
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// If the enum was not imported, the derived conformance is either from the
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// enum itself or an extension, in which case we will emit the declaration
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// normally.
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if (enumDecl->hasClangNode())
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tc.Context.addExternalDecl(eqDecl);
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// Add the operator to the parent scope.
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cast<IterableDeclContext>(parentDecl)->addMember(eqDecl);
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return eqDecl;
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}
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ValueDecl *DerivedConformance::deriveEquatable(TypeChecker &tc,
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Decl *parentDecl,
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NominalTypeDecl *type,
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ValueDecl *requirement) {
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// Check that we can actually derive Equatable for this type.
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if (!canDeriveConformance(type))
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return nullptr;
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// Build the necessary decl.
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if (requirement->getName().str() == "==") {
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if (auto theEnum = dyn_cast<EnumDecl>(type))
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return deriveEquatable_enum_eq(tc, parentDecl, theEnum);
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else
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llvm_unreachable("todo");
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}
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tc.diagnose(requirement->getLoc(),
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diag::broken_equatable_requirement);
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return nullptr;
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}
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static void
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deriveBodyHashable_enum_hashValue(AbstractFunctionDecl *hashValueDecl) {
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auto parentDC = hashValueDecl->getDeclContext();
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ASTContext &C = parentDC->getASTContext();
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auto enumDecl = parentDC->getAsEnumOrEnumExtensionContext();
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SmallVector<ASTNode, 3> statements;
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auto selfDecl = hashValueDecl->getImplicitSelfDecl();
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DeclRefExpr *indexRef = convertEnumToIndex(statements, parentDC, enumDecl,
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selfDecl, hashValueDecl, "index");
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auto memberRef = new (C) UnresolvedDotExpr(indexRef, SourceLoc(),
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C.Id_hashValue,
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DeclNameLoc(),
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/*implicit*/true);
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auto returnStmt = new (C) ReturnStmt(SourceLoc(), memberRef);
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statements.push_back(returnStmt);
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auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
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hashValueDecl->setBody(body);
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}
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/// Derive a 'hashValue' implementation for an enum.
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static ValueDecl *
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deriveHashable_enum_hashValue(TypeChecker &tc, Decl *parentDecl,
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EnumDecl *enumDecl) {
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// enum SomeEnum {
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// case A, B, C
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// @derived var hashValue: Int {
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// var index: Int
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// switch self {
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// case A:
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// index = 0
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// case B:
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// index = 1
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// case C:
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// index = 2
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// }
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// return index.hashValue
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// }
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// }
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ASTContext &C = tc.Context;
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auto parentDC = cast<DeclContext>(parentDecl);
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Type intType = C.getIntDecl()->getDeclaredType();
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// We can't form a Hashable conformance if Int isn't Hashable or
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// ExpressibleByIntegerLiteral.
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if (!tc.conformsToProtocol(intType,C.getProtocol(KnownProtocolKind::Hashable),
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enumDecl, None)) {
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tc.diagnose(enumDecl->getLoc(), diag::broken_int_hashable_conformance);
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return nullptr;
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}
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ProtocolDecl *intLiteralProto =
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C.getProtocol(KnownProtocolKind::ExpressibleByIntegerLiteral);
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if (!tc.conformsToProtocol(intType, intLiteralProto, enumDecl, None)) {
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tc.diagnose(enumDecl->getLoc(),
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diag::broken_int_integer_literal_convertible_conformance);
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return nullptr;
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}
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auto selfDecl = ParamDecl::createUnboundSelf(SourceLoc(), parentDC);
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ParameterList *params[] = {
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ParameterList::createWithoutLoc(selfDecl),
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ParameterList::createEmpty(C)
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};
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FuncDecl *getterDecl =
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FuncDecl::create(C, /*StaticLoc=*/SourceLoc(), StaticSpellingKind::None,
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/*FuncLoc=*/SourceLoc(),
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Identifier(), /*NameLoc=*/SourceLoc(),
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/*Throws=*/false, /*ThrowsLoc=*/SourceLoc(),
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/*AccessorKeywordLoc=*/SourceLoc(),
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/*GenericParams=*/nullptr, params,
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Type(), TypeLoc::withoutLoc(intType), parentDC);
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getterDecl->setImplicit();
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getterDecl->setBodySynthesizer(deriveBodyHashable_enum_hashValue);
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// Compute the type of hashValue().
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GenericParamList *genericParams = getterDecl->getGenericParamsOfContext();
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Type methodType = FunctionType::get(TupleType::getEmpty(tc.Context), intType);
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Type selfType = getterDecl->computeSelfType();
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selfDecl->overwriteType(selfType);
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Type type;
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if (genericParams)
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type = PolymorphicFunctionType::get(selfType, methodType, genericParams);
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else
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type = FunctionType::get(selfType, methodType);
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getterDecl->setType(type);
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getterDecl->setBodyResultType(intType);
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// Compute the interface type of hashValue().
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Type interfaceType;
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Type selfIfaceType = getterDecl->computeInterfaceSelfType(false);
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if (auto sig = parentDC->getGenericSignatureOfContext()) {
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getterDecl->setGenericSignature(sig);
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interfaceType = GenericFunctionType::get(sig, selfIfaceType, methodType,
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AnyFunctionType::ExtInfo());
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} else
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interfaceType = FunctionType::get(selfType, methodType);
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getterDecl->setInterfaceType(interfaceType);
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getterDecl->setAccessibility(std::max(Accessibility::Internal,
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enumDecl->getFormalAccess()));
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// If the enum was not imported, the derived conformance is either from the
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// enum itself or an extension, in which case we will emit the declaration
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// normally.
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if (enumDecl->hasClangNode())
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tc.Context.addExternalDecl(getterDecl);
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// Create the property.
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VarDecl *hashValueDecl = new (C) VarDecl(/*static*/ false,
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/*let*/ false,
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SourceLoc(), C.Id_hashValue,
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intType, parentDC);
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hashValueDecl->setImplicit();
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hashValueDecl->makeComputed(SourceLoc(), getterDecl,
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nullptr, nullptr, SourceLoc());
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hashValueDecl->setAccessibility(getterDecl->getFormalAccess());
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Pattern *hashValuePat = new (C) NamedPattern(hashValueDecl, /*implicit*/true);
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hashValuePat->setType(intType);
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hashValuePat
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= new (C) TypedPattern(hashValuePat, TypeLoc::withoutLoc(intType),
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/*implicit*/ true);
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hashValuePat->setType(intType);
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auto patDecl = PatternBindingDecl::create(C, SourceLoc(),
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StaticSpellingKind::None,
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SourceLoc(), hashValuePat, nullptr,
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parentDC);
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patDecl->setImplicit();
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auto dc = cast<IterableDeclContext>(parentDecl);
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dc->addMember(getterDecl);
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dc->addMember(hashValueDecl);
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dc->addMember(patDecl);
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return hashValueDecl;
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}
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ValueDecl *DerivedConformance::deriveHashable(TypeChecker &tc,
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Decl *parentDecl,
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NominalTypeDecl *type,
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ValueDecl *requirement) {
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// Check that we can actually derive Hashable for this type.
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if (!canDeriveConformance(type))
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return nullptr;
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// Build the necessary decl.
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if (requirement->getName().str() == "hashValue") {
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if (auto theEnum = dyn_cast<EnumDecl>(type))
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return deriveHashable_enum_hashValue(tc, parentDecl, theEnum);
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else
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llvm_unreachable("todo");
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}
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tc.diagnose(requirement->getLoc(),
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diag::broken_hashable_requirement);
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return nullptr;
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}
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