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7499c222ee
Direct lookup relied in primary file checking to have filled in the protocol type stored in the ImplementsAttr. This was already wrong with multi-file test cases in non-WMO mode, and crashed in the ASTPrinter if printing a declaration in a non-primary file. I don't have a standalone test case that is independent of my upcoming ASTPrinter changes, but this is a nice cleanup regardless.
347 lines
14 KiB
C++
347 lines
14 KiB
C++
//===--- DerivedConformanceComparable.cpp - Derived Comparable -===//
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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 - 2020 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 Comparable protocol.
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// (Most of this code is similar to code in `DerivedConformanceEquatableHashable.cpp`)
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//
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//===----------------------------------------------------------------------===//
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#include "CodeSynthesis.h"
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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/ProtocolConformance.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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static std::pair<BraceStmt *, bool>
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deriveBodyComparable_enum_uninhabited_lt(AbstractFunctionDecl *ltDecl, void *) {
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auto parentDC = ltDecl->getDeclContext();
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ASTContext &C = parentDC->getASTContext();
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auto args = ltDecl->getParameters();
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auto aParam = args->get(0);
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auto bParam = args->get(1);
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assert(!cast<EnumDecl>(aParam->getType()->getAnyNominal())->hasCases());
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assert(!cast<EnumDecl>(bParam->getType()->getAnyNominal())->hasCases());
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SmallVector<ASTNode, 0> statements;
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auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
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return { body, /*isTypeChecked=*/true };
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}
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/// Derive the body for a '<' operator for an enum that has no associated
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/// values. This generates code that converts each value to its integer ordinal
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/// and compares them, which produces an optimal single icmp instruction.
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static std::pair<BraceStmt *, bool>
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deriveBodyComparable_enum_noAssociatedValues_lt(AbstractFunctionDecl *ltDecl,
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void *) {
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auto parentDC = ltDecl->getDeclContext();
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ASTContext &C = parentDC->getASTContext();
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auto args = ltDecl->getParameters();
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auto aParam = args->get(0);
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auto bParam = args->get(1);
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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, 8> statements;
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DeclRefExpr *aIndex = DerivedConformance::convertEnumToIndex(statements, parentDC, enumDecl,
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aParam, ltDecl, "index_a");
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DeclRefExpr *bIndex = DerivedConformance::convertEnumToIndex(statements, parentDC, enumDecl,
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bParam, ltDecl, "index_b");
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// Generate the compare of the indices.
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FuncDecl *cmpFunc = C.getLessThanIntDecl();
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assert(cmpFunc && "should have a < for int as we already checked for it");
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Expr *cmpFuncExpr = new (C) DeclRefExpr(cmpFunc, DeclNameLoc(),
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/*implicit*/ true,
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AccessSemantics::Ordinary);
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auto *cmpExpr =
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BinaryExpr::create(C, aIndex, cmpFuncExpr, bIndex, /*implicit*/ true);
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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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return { body, /*isTypeChecked=*/false };
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}
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/// Derive the body for an '==' operator for an enum where at least one of the
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/// cases has associated values.
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static std::pair<BraceStmt *, bool>
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deriveBodyComparable_enum_hasAssociatedValues_lt(AbstractFunctionDecl *ltDecl, void *) {
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auto parentDC = ltDecl->getDeclContext();
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ASTContext &C = parentDC->getASTContext();
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auto args = ltDecl->getParameters();
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auto aParam = args->get(0);
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auto bParam = args->get(1);
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Type enumType = aParam->getType();
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auto enumDecl = cast<EnumDecl>(aParam->getType()->getAnyNominal());
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SmallVector<ASTNode, 8> statements;
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SmallVector<ASTNode, 4> cases;
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unsigned elementCount = 0; // need this as `getAllElements` returns a generator
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// For each enum element, generate a case statement matching a pair containing
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// the same case, binding variables for the left- and right-hand associated
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// values.
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for (auto elt : enumDecl->getAllElements()) {
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++elementCount;
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// .<elt>(let l0, let l1, ...)
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SmallVector<VarDecl*, 4> lhsPayloadVars;
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auto lhsSubpattern = DerivedConformance::enumElementPayloadSubpattern(elt, 'l', ltDecl,
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lhsPayloadVars);
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auto *lhsBaseTE = TypeExpr::createImplicit(enumType, C);
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auto lhsElemPat = new (C)
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EnumElementPattern(lhsBaseTE, SourceLoc(), DeclNameLoc(), DeclNameRef(),
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elt, lhsSubpattern, /*DC*/ ltDecl);
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lhsElemPat->setImplicit();
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// .<elt>(let r0, let r1, ...)
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SmallVector<VarDecl*, 4> rhsPayloadVars;
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auto rhsSubpattern = DerivedConformance::enumElementPayloadSubpattern(elt, 'r', ltDecl,
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rhsPayloadVars);
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auto *rhsBaseTE = TypeExpr::createImplicit(enumType, C);
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auto rhsElemPat = new (C)
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EnumElementPattern(rhsBaseTE, SourceLoc(), DeclNameLoc(), DeclNameRef(),
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elt, rhsSubpattern, /*DC*/ ltDecl);
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rhsElemPat->setImplicit();
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auto hasBoundDecls = !lhsPayloadVars.empty();
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Optional<MutableArrayRef<VarDecl *>> caseBodyVarDecls;
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if (hasBoundDecls) {
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// We allocated a direct copy of our lhs var decls for the case
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// body.
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auto copy = C.Allocate<VarDecl *>(lhsPayloadVars.size());
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for (unsigned i : indices(lhsPayloadVars)) {
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auto *vOld = lhsPayloadVars[i];
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auto *vNew = new (C) VarDecl(
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/*IsStatic*/ false, vOld->getIntroducer(),
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vOld->getNameLoc(), vOld->getName(), vOld->getDeclContext());
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vNew->setImplicit();
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copy[i] = vNew;
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}
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caseBodyVarDecls.emplace(copy);
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}
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// case (.<elt>(let l0, let l1, ...), .<elt>(let r0, let r1, ...))
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auto caseTuplePattern = TuplePattern::createImplicit(C, {
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TuplePatternElt(lhsElemPat), TuplePatternElt(rhsElemPat) });
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caseTuplePattern->setImplicit();
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auto labelItem = CaseLabelItem(caseTuplePattern);
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// Generate a guard statement for each associated value in the payload,
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// breaking out early if any pair is unequal. (same as Equatable synthesis.)
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// the else statement performs the lexicographic comparison.
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SmallVector<ASTNode, 8> statementsInCase;
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for (size_t varIdx = 0; varIdx < lhsPayloadVars.size(); ++varIdx) {
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auto lhsVar = lhsPayloadVars[varIdx];
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auto lhsExpr = new (C) DeclRefExpr(lhsVar, DeclNameLoc(),
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/*implicit*/true);
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auto rhsVar = rhsPayloadVars[varIdx];
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auto rhsExpr = new (C) DeclRefExpr(rhsVar, DeclNameLoc(),
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/*Implicit*/true);
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auto guardStmt = DerivedConformance::returnComparisonIfNotEqualGuard(C,
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lhsExpr, rhsExpr);
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statementsInCase.emplace_back(guardStmt);
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}
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// If none of the guard statements caused an early exit, then all the pairs
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// were true. (equal)
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// return false
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auto falseExpr = new (C) BooleanLiteralExpr(false, SourceLoc(),
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/*Implicit*/true);
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auto returnStmt = new (C) ReturnStmt(SourceLoc(), falseExpr);
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statementsInCase.push_back(returnStmt);
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auto body = BraceStmt::create(C, SourceLoc(), statementsInCase,
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SourceLoc());
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cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
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labelItem, SourceLoc(), SourceLoc(), body,
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caseBodyVarDecls));
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}
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// default: result = <enum index>(lhs) < <enum index>(rhs)
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//
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// We only generate this if the enum has more than one case. If it has exactly
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// one case, then that single case statement is already exhaustive.
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if (elementCount > 1) {
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auto defaultPattern = AnyPattern::createImplicit(C);
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auto defaultItem = CaseLabelItem::getDefault(defaultPattern);
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auto body = deriveBodyComparable_enum_noAssociatedValues_lt(ltDecl, nullptr).first;
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cases.push_back(CaseStmt::create(C, CaseParentKind::Switch, SourceLoc(),
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defaultItem, SourceLoc(), SourceLoc(),
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body,
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/*case body var decls*/ None));
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}
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// switch (a, b) { <case statements> }
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auto aRef = new (C) DeclRefExpr(aParam, DeclNameLoc(), /*implicit*/true);
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auto bRef = new (C) DeclRefExpr(bParam, DeclNameLoc(), /*implicit*/true);
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auto abExpr = TupleExpr::createImplicit(C, {aRef, bRef}, /*labels*/ {});
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auto switchStmt =
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SwitchStmt::createImplicit(LabeledStmtInfo(), abExpr, cases, C);
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statements.push_back(switchStmt);
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auto body = BraceStmt::create(C, SourceLoc(), statements, SourceLoc());
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return { body, /*isTypeChecked=*/false };
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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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deriveComparable_lt(
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DerivedConformance &derived,
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std::pair<BraceStmt *, bool> (*bodySynthesizer)(AbstractFunctionDecl *,
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void *)) {
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ASTContext &C = derived.Context;
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auto parentDC = derived.getConformanceContext();
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auto selfIfaceTy = parentDC->getDeclaredInterfaceType();
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auto getParamDecl = [&](StringRef s) -> ParamDecl * {
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auto *param = new (C) ParamDecl(SourceLoc(),
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SourceLoc(), Identifier(), SourceLoc(),
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C.getIdentifier(s), parentDC);
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param->setSpecifier(ParamSpecifier::Default);
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param->setInterfaceType(selfIfaceTy);
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param->setImplicit();
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return param;
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};
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ParameterList *params = ParameterList::create(C, {
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getParamDecl("a"),
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getParamDecl("b")
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});
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auto boolTy = C.getBoolType();
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Identifier generatedIdentifier;
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if (parentDC->getParentModule()->isResilient()) {
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generatedIdentifier = C.Id_LessThanOperator;
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} else {
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assert(selfIfaceTy->getEnumOrBoundGenericEnum());
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generatedIdentifier = C.Id_derived_enum_less_than;
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}
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DeclName name(C, generatedIdentifier, params);
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auto *const comparableDecl = FuncDecl::createImplicit(
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C, StaticSpellingKind::KeywordStatic, name, /*NameLoc=*/SourceLoc(),
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/*Async=*/false,
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/*Throws=*/false,
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/*GenericParams=*/nullptr, params, boolTy, parentDC);
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comparableDecl->setUserAccessible(false);
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// Add the @_implements(Comparable, < (_:_:)) attribute
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if (generatedIdentifier != C.Id_LessThanOperator) {
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auto comparable = C.getProtocol(KnownProtocolKind::Comparable);
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SmallVector<Identifier, 2> argumentLabels = { Identifier(), Identifier() };
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auto comparableDeclName = DeclName(C, DeclBaseName(C.Id_LessThanOperator),
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argumentLabels);
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comparableDecl->getAttrs().add(ImplementsAttr::create(parentDC,
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comparable,
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comparableDeclName));
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}
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if (!C.getLessThanIntDecl()) {
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derived.ConformanceDecl->diagnose(diag::no_less_than_overload_for_int);
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return nullptr;
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}
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addNonIsolatedToSynthesized(derived.Nominal, comparableDecl);
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comparableDecl->setBodySynthesizer(bodySynthesizer);
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comparableDecl->copyFormalAccessFrom(derived.Nominal, /*sourceIsParentContext*/ true);
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// Add the operator to the parent scope.
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derived.addMembersToConformanceContext({comparableDecl});
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return comparableDecl;
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}
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// for now, only enums can synthesize `Comparable`, so this function can take
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// an `EnumDecl` instead of a `NominalTypeDecl`
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bool
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DerivedConformance::canDeriveComparable(DeclContext *context, EnumDecl *enumeration) {
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// The type must be an enum.
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if (!enumeration) {
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return false;
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}
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auto comparable = context->getASTContext().getProtocol(KnownProtocolKind::Comparable);
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if (!comparable) {
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return false; // not sure what should be done here instead
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}
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// The cases must not have non-comparable associated values or raw backing
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return allAssociatedValuesConformToProtocol(context, enumeration, comparable) && !enumeration->hasRawType();
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}
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ValueDecl *DerivedConformance::deriveComparable(ValueDecl *requirement) {
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if (checkAndDiagnoseDisallowedContext(requirement)) {
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return nullptr;
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}
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if (requirement->getBaseName() != "<") {
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requirement->diagnose(diag::broken_comparable_requirement);
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return nullptr;
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}
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// Build the necessary decl.
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auto enumeration = dyn_cast<EnumDecl>(this->Nominal);
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assert(enumeration);
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std::pair<BraceStmt *, bool> (*synthesizer)(AbstractFunctionDecl *, void *);
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if (enumeration->hasCases()) {
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if (enumeration->hasOnlyCasesWithoutAssociatedValues()) {
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synthesizer = &deriveBodyComparable_enum_noAssociatedValues_lt;
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} else {
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synthesizer = &deriveBodyComparable_enum_hasAssociatedValues_lt;
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}
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} else {
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synthesizer = &deriveBodyComparable_enum_uninhabited_lt;
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}
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return deriveComparable_lt(*this, synthesizer);
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}
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void DerivedConformance::tryDiagnoseFailedComparableDerivation(
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DeclContext *DC, NominalTypeDecl *nominal) {
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auto &ctx = DC->getASTContext();
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auto *comparableProto = ctx.getProtocol(KnownProtocolKind::Comparable);
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diagnoseAnyNonConformingMemberTypes(DC, nominal, comparableProto);
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diagnoseIfSynthesisUnsupportedForDecl(nominal, comparableProto);
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if (auto enumDecl = dyn_cast<EnumDecl>(nominal)) {
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if (enumDecl->hasRawType() && !enumDecl->getRawType()->is<ErrorType>()) {
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auto rawType = enumDecl->getRawType();
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auto rawTypeLoc = enumDecl->getInherited()[0].getSourceRange().Start;
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ctx.Diags.diagnose(rawTypeLoc,
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diag::comparable_synthesis_raw_value_not_allowed,
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rawType, nominal->getDeclaredInterfaceType(),
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comparableProto->getDeclaredInterfaceType());
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}
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}
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}
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