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5b3c4b6844
* Use the presence of an argument type to check for associated values hasOnlyCasesWithoutAssociatedValues returns true for any serialized enum declaration whether or not it has cases. This never really came up because it's mostly relevant to Sema's proto-deriving mechanism. Fix this by using the presence of the case's argument type instead. * Separate checks for presence of cases and enum simplicity Necessary because the old behavior was an artifact of the implementation.
483 lines
19 KiB
C++
483 lines
19 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 - 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 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/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/Module.h"
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#include "swift/AST/Pattern.h"
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#include "swift/AST/ParameterList.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 have cases.
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if (!enumDecl->hasCases())
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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(/*IsStatic*/false, /*IsLet*/false,
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/*IsCaptureList*/false, SourceLoc(),
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C.getIdentifier(indexName), intType,
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funcDecl);
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indexVar->setInterfaceType(intType);
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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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auto boolTy = C.getBoolDecl()->getDeclaredType();
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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();
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assert(cmpFunc && "should have a == for int as we already checked for it");
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auto fnType = cast<FunctionType>(cmpFunc->getInterfaceType()
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->getCanonicalType());
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Expr *cmpFuncExpr;
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if (cmpFunc->getDeclContext()->isTypeContext()) {
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auto contextTy = cmpFunc->getDeclContext()->getSelfInterfaceType();
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Expr *base = TypeExpr::createImplicitHack(SourceLoc(), contextTy, C);
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Expr *ref = new (C) DeclRefExpr(cmpFunc, DeclNameLoc(), /*Implicit*/ true,
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AccessSemantics::Ordinary, fnType);
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fnType = cast<FunctionType>(fnType.getResult());
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cmpFuncExpr = new (C) DotSyntaxCallExpr(ref, SourceLoc(), base, fnType);
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cmpFuncExpr->setImplicit();
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} else {
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cmpFuncExpr = new (C) DeclRefExpr(cmpFunc, DeclNameLoc(),
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/*implicit*/ true,
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AccessSemantics::Ordinary,
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fnType);
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}
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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 *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 enumIfaceTy = parentDC->getDeclaredInterfaceType();
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auto getParamDecl = [&](StringRef s) -> ParamDecl* {
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auto *param = 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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param->setInterfaceType(enumIfaceTy);
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return param;
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};
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auto selfDecl = ParamDecl::createSelf(SourceLoc(), parentDC,
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/*isStatic=*/true);
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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,
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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()) {
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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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eqDecl->setOperatorDecl(op);
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eqDecl->setBodySynthesizer(&deriveBodyEquatable_enum_eq);
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// Compute the type.
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Type paramsTy = params[1]->getType(tc.Context);
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// Compute the interface type.
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Type interfaceTy;
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Type selfIfaceTy = eqDecl->computeInterfaceSelfType();
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if (auto genericSig = parentDC->getGenericSignatureOfContext()) {
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eqDecl->setGenericEnvironment(parentDC->getGenericEnvironmentOfContext());
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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::createSelf(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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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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Type methodType = FunctionType::get(TupleType::getEmpty(tc.Context), 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();
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if (auto sig = parentDC->getGenericSignatureOfContext()) {
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getterDecl->setGenericEnvironment(parentDC->getGenericEnvironmentOfContext());
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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(selfIfaceType, 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(/*IsStatic*/false, /*IsLet*/false,
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/*IsCaptureList*/false, SourceLoc(),
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C.Id_hashValue, intType, parentDC);
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hashValueDecl->setImplicit();
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hashValueDecl->setInterfaceType(intType);
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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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}
|