145 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#include "NSInvocationArgumentLifetimeCheck.h"10#include "clang/AST/ASTContext.h"11#include "clang/AST/ComputeDependence.h"12#include "clang/AST/Decl.h"13#include "clang/AST/Expr.h"14#include "clang/AST/ExprObjC.h"15#include "clang/AST/Type.h"16#include "clang/AST/TypeLoc.h"17#include "clang/ASTMatchers/ASTMatchFinder.h"18#include "clang/ASTMatchers/ASTMatchers.h"19#include "clang/ASTMatchers/ASTMatchersMacros.h"20#include "clang/Basic/Diagnostic.h"21#include "clang/Basic/LLVM.h"22#include "clang/Basic/LangOptions.h"23#include "clang/Basic/SourceLocation.h"24#include "clang/Basic/SourceManager.h"25#include "clang/Lex/Lexer.h"26#include "llvm/ADT/StringRef.h"27#include <optional>28 29using namespace clang::ast_matchers;30 31namespace clang::tidy::objc {32 33static constexpr StringRef WeakText = "__weak";34static constexpr StringRef StrongText = "__strong";35static constexpr StringRef UnsafeUnretainedText = "__unsafe_unretained";36 37namespace {38 39/// Matches ObjCIvarRefExpr, DeclRefExpr, or MemberExpr that reference40/// Objective-C object (or block) variables or fields whose object lifetimes41/// are not __unsafe_unretained.42AST_POLYMORPHIC_MATCHER(isObjCManagedLifetime,43 AST_POLYMORPHIC_SUPPORTED_TYPES(ObjCIvarRefExpr,44 DeclRefExpr,45 MemberExpr)) {46 const QualType QT = Node.getType();47 return QT->isScalarType() &&48 (QT->getScalarTypeKind() == Type::STK_ObjCObjectPointer ||49 QT->getScalarTypeKind() == Type::STK_BlockPointer) &&50 QT.getQualifiers().getObjCLifetime() > Qualifiers::OCL_ExplicitNone;51}52 53} // namespace54 55static std::optional<FixItHint>56fixItHintReplacementForOwnershipString(StringRef Text, CharSourceRange Range,57 StringRef Ownership) {58 const size_t Index = Text.find(Ownership);59 if (Index == StringRef::npos)60 return std::nullopt;61 62 const SourceLocation Begin = Range.getBegin().getLocWithOffset(Index);63 const SourceLocation End = Begin.getLocWithOffset(Ownership.size());64 return FixItHint::CreateReplacement(SourceRange(Begin, End),65 UnsafeUnretainedText);66}67 68static std::optional<FixItHint>69fixItHintForVarDecl(const VarDecl *VD, const SourceManager &SM,70 const LangOptions &LangOpts) {71 assert(VD && "VarDecl parameter must not be null");72 // Don't provide fix-its for any parameter variables at this time.73 if (isa<ParmVarDecl>(VD))74 return std::nullopt;75 76 // Currently there is no way to directly get the source range for the77 // __weak/__strong ObjC lifetime qualifiers, so it's necessary to string78 // search in the source code.79 const CharSourceRange Range = Lexer::makeFileCharRange(80 CharSourceRange::getTokenRange(VD->getSourceRange()), SM, LangOpts);81 if (Range.isInvalid()) {82 // An invalid range likely means inside a macro, in which case don't supply83 // a fix-it.84 return std::nullopt;85 }86 87 const StringRef VarDeclText = Lexer::getSourceText(Range, SM, LangOpts);88 if (std::optional<FixItHint> Hint =89 fixItHintReplacementForOwnershipString(VarDeclText, Range, WeakText))90 return Hint;91 92 if (std::optional<FixItHint> Hint = fixItHintReplacementForOwnershipString(93 VarDeclText, Range, StrongText))94 return Hint;95 96 return FixItHint::CreateInsertion(Range.getBegin(), "__unsafe_unretained ");97}98 99void NSInvocationArgumentLifetimeCheck::registerMatchers(MatchFinder *Finder) {100 Finder->addMatcher(101 traverse(102 TK_AsIs,103 objcMessageExpr(104 hasReceiverType(asString("NSInvocation *")),105 anyOf(hasSelector("getArgument:atIndex:"),106 hasSelector("getReturnValue:")),107 hasArgument(108 0,109 anyOf(hasDescendant(memberExpr(isObjCManagedLifetime())),110 hasDescendant(objcIvarRefExpr(isObjCManagedLifetime())),111 hasDescendant(112 // Reference to variables, but when dereferencing113 // to ivars/fields a more-descendent variable114 // reference (e.g. self) may match with strong115 // object lifetime, leading to an incorrect match.116 // Exclude these conditions.117 declRefExpr(to(varDecl().bind("var")),118 unless(hasParent(implicitCastExpr())),119 isObjCManagedLifetime())))))120 .bind("call")),121 this);122}123 124void NSInvocationArgumentLifetimeCheck::check(125 const MatchFinder::MatchResult &Result) {126 const auto *MatchedExpr = Result.Nodes.getNodeAs<ObjCMessageExpr>("call");127 128 auto Diag = diag(MatchedExpr->getArg(0)->getBeginLoc(),129 "NSInvocation %objcinstance0 should only pass pointers to "130 "objects with ownership __unsafe_unretained")131 << MatchedExpr->getSelector();132 133 // Only provide fix-it hints for references to local variables; fixes for134 // instance variable references don't have as clear an automated fix.135 const auto *VD = Result.Nodes.getNodeAs<VarDecl>("var");136 if (!VD)137 return;138 139 if (auto Hint = fixItHintForVarDecl(VD, *Result.SourceManager,140 Result.Context->getLangOpts()))141 Diag << *Hint;142}143 144} // namespace clang::tidy::objc145