| //===--- LoopConvertCheck.cpp - clang-tidy---------------------------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "LoopConvertCheck.h" |
| #include "clang/AST/ASTContext.h" |
| #include "clang/ASTMatchers/ASTMatchFinder.h" |
| |
| using namespace clang; |
| using namespace clang::ast_matchers; |
| using namespace llvm; |
| |
| namespace clang { |
| namespace tidy { |
| namespace modernize { |
| |
| const char LoopNameArray[] = "forLoopArray"; |
| const char LoopNameIterator[] = "forLoopIterator"; |
| const char LoopNamePseudoArray[] = "forLoopPseudoArray"; |
| const char ConditionBoundName[] = "conditionBound"; |
| const char ConditionVarName[] = "conditionVar"; |
| const char IncrementVarName[] = "incrementVar"; |
| const char InitVarName[] = "initVar"; |
| const char BeginCallName[] = "beginCall"; |
| const char EndCallName[] = "endCall"; |
| const char ConditionEndVarName[] = "conditionEndVar"; |
| const char EndVarName[] = "endVar"; |
| const char DerefByValueResultName[] = "derefByValueResult"; |
| const char DerefByRefResultName[] = "derefByRefResult"; |
| |
| // shared matchers |
| static const TypeMatcher AnyType = anything(); |
| |
| static const StatementMatcher IntegerComparisonMatcher = |
| expr(ignoringParenImpCasts( |
| declRefExpr(to(varDecl(hasType(isInteger())).bind(ConditionVarName))))); |
| |
| static const DeclarationMatcher InitToZeroMatcher = |
| varDecl(hasInitializer(ignoringParenImpCasts(integerLiteral(equals(0))))) |
| .bind(InitVarName); |
| |
| static const StatementMatcher IncrementVarMatcher = |
| declRefExpr(to(varDecl(hasType(isInteger())).bind(IncrementVarName))); |
| |
| /// \brief The matcher for loops over arrays. |
| /// |
| /// In this general example, assuming 'j' and 'k' are of integral type: |
| /// \code |
| /// for (int i = 0; j < 3 + 2; ++k) { ... } |
| /// \endcode |
| /// The following string identifiers are bound to these parts of the AST: |
| /// ConditionVarName: 'j' (as a VarDecl) |
| /// ConditionBoundName: '3 + 2' (as an Expr) |
| /// InitVarName: 'i' (as a VarDecl) |
| /// IncrementVarName: 'k' (as a VarDecl) |
| /// LoopName: The entire for loop (as a ForStmt) |
| /// |
| /// Client code will need to make sure that: |
| /// - The three index variables identified by the matcher are the same |
| /// VarDecl. |
| /// - The index variable is only used as an array index. |
| /// - All arrays indexed by the loop are the same. |
| StatementMatcher makeArrayLoopMatcher() { |
| StatementMatcher ArrayBoundMatcher = |
| expr(hasType(isInteger())).bind(ConditionBoundName); |
| |
| return forStmt( |
| hasLoopInit(declStmt(hasSingleDecl(InitToZeroMatcher))), |
| hasCondition(anyOf( |
| binaryOperator(hasOperatorName("<"), |
| hasLHS(IntegerComparisonMatcher), |
| hasRHS(ArrayBoundMatcher)), |
| binaryOperator(hasOperatorName(">"), hasLHS(ArrayBoundMatcher), |
| hasRHS(IntegerComparisonMatcher)))), |
| hasIncrement(unaryOperator(hasOperatorName("++"), |
| hasUnaryOperand(IncrementVarMatcher)))) |
| .bind(LoopNameArray); |
| } |
| |
| /// \brief The matcher used for iterator-based for loops. |
| /// |
| /// This matcher is more flexible than array-based loops. It will match |
| /// catch loops of the following textual forms (regardless of whether the |
| /// iterator type is actually a pointer type or a class type): |
| /// |
| /// Assuming f, g, and h are of type containerType::iterator, |
| /// \code |
| /// for (containerType::iterator it = container.begin(), |
| /// e = createIterator(); f != g; ++h) { ... } |
| /// for (containerType::iterator it = container.begin(); |
| /// f != anotherContainer.end(); ++h) { ... } |
| /// \endcode |
| /// The following string identifiers are bound to the parts of the AST: |
| /// InitVarName: 'it' (as a VarDecl) |
| /// ConditionVarName: 'f' (as a VarDecl) |
| /// LoopName: The entire for loop (as a ForStmt) |
| /// In the first example only: |
| /// EndVarName: 'e' (as a VarDecl) |
| /// ConditionEndVarName: 'g' (as a VarDecl) |
| /// In the second example only: |
| /// EndCallName: 'container.end()' (as a CXXMemberCallExpr) |
| /// |
| /// Client code will need to make sure that: |
| /// - The iterator variables 'it', 'f', and 'h' are the same. |
| /// - The two containers on which 'begin' and 'end' are called are the same. |
| /// - If the end iterator variable 'g' is defined, it is the same as 'f'. |
| StatementMatcher makeIteratorLoopMatcher() { |
| StatementMatcher BeginCallMatcher = |
| memberCallExpr(argumentCountIs(0), callee(methodDecl(hasName("begin")))) |
| .bind(BeginCallName); |
| |
| DeclarationMatcher InitDeclMatcher = |
| varDecl(hasInitializer(anyOf(ignoringParenImpCasts(BeginCallMatcher), |
| materializeTemporaryExpr( |
| ignoringParenImpCasts(BeginCallMatcher)), |
| hasDescendant(BeginCallMatcher)))) |
| .bind(InitVarName); |
| |
| DeclarationMatcher EndDeclMatcher = |
| varDecl(hasInitializer(anything())).bind(EndVarName); |
| |
| StatementMatcher EndCallMatcher = |
| memberCallExpr(argumentCountIs(0), callee(methodDecl(hasName("end")))); |
| |
| StatementMatcher IteratorBoundMatcher = |
| expr(anyOf(ignoringParenImpCasts( |
| declRefExpr(to(varDecl().bind(ConditionEndVarName)))), |
| ignoringParenImpCasts(expr(EndCallMatcher).bind(EndCallName)), |
| materializeTemporaryExpr(ignoringParenImpCasts( |
| expr(EndCallMatcher).bind(EndCallName))))); |
| |
| StatementMatcher IteratorComparisonMatcher = expr( |
| ignoringParenImpCasts(declRefExpr(to(varDecl().bind(ConditionVarName))))); |
| |
| StatementMatcher OverloadedNEQMatcher = |
| operatorCallExpr(hasOverloadedOperatorName("!="), argumentCountIs(2), |
| hasArgument(0, IteratorComparisonMatcher), |
| hasArgument(1, IteratorBoundMatcher)); |
| |
| // This matcher tests that a declaration is a CXXRecordDecl that has an |
| // overloaded operator*(). If the operator*() returns by value instead of by |
| // reference then the return type is tagged with DerefByValueResultName. |
| internal::Matcher<VarDecl> TestDerefReturnsByValue = |
| hasType(recordDecl(hasMethod(allOf( |
| hasOverloadedOperatorName("*"), |
| anyOf( |
| // Tag the return type if it's by value. |
| returns(qualType(unless(hasCanonicalType(referenceType()))) |
| .bind(DerefByValueResultName)), |
| returns( |
| // Skip loops where the iterator's operator* returns an |
| // rvalue reference. This is just weird. |
| qualType(unless(hasCanonicalType(rValueReferenceType()))) |
| .bind(DerefByRefResultName))))))); |
| |
| return forStmt( |
| hasLoopInit(anyOf(declStmt(declCountIs(2), |
| containsDeclaration(0, InitDeclMatcher), |
| containsDeclaration(1, EndDeclMatcher)), |
| declStmt(hasSingleDecl(InitDeclMatcher)))), |
| hasCondition( |
| anyOf(binaryOperator(hasOperatorName("!="), |
| hasLHS(IteratorComparisonMatcher), |
| hasRHS(IteratorBoundMatcher)), |
| binaryOperator(hasOperatorName("!="), |
| hasLHS(IteratorBoundMatcher), |
| hasRHS(IteratorComparisonMatcher)), |
| OverloadedNEQMatcher)), |
| hasIncrement(anyOf( |
| unaryOperator(hasOperatorName("++"), |
| hasUnaryOperand(declRefExpr( |
| to(varDecl(hasType(pointsTo(AnyType))) |
| .bind(IncrementVarName))))), |
| operatorCallExpr( |
| hasOverloadedOperatorName("++"), |
| hasArgument( |
| 0, declRefExpr(to(varDecl(TestDerefReturnsByValue) |
| .bind(IncrementVarName)))))))) |
| .bind(LoopNameIterator); |
| } |
| |
| /// \brief The matcher used for array-like containers (pseudoarrays). |
| /// |
| /// This matcher is more flexible than array-based loops. It will match |
| /// loops of the following textual forms (regardless of whether the |
| /// iterator type is actually a pointer type or a class type): |
| /// |
| /// Assuming f, g, and h are of type containerType::iterator, |
| /// \code |
| /// for (int i = 0, j = container.size(); f < g; ++h) { ... } |
| /// for (int i = 0; f < container.size(); ++h) { ... } |
| /// \endcode |
| /// The following string identifiers are bound to the parts of the AST: |
| /// InitVarName: 'i' (as a VarDecl) |
| /// ConditionVarName: 'f' (as a VarDecl) |
| /// LoopName: The entire for loop (as a ForStmt) |
| /// In the first example only: |
| /// EndVarName: 'j' (as a VarDecl) |
| /// ConditionEndVarName: 'g' (as a VarDecl) |
| /// In the second example only: |
| /// EndCallName: 'container.size()' (as a CXXMemberCallExpr) |
| /// |
| /// Client code will need to make sure that: |
| /// - The index variables 'i', 'f', and 'h' are the same. |
| /// - The containers on which 'size()' is called is the container indexed. |
| /// - The index variable is only used in overloaded operator[] or |
| /// container.at(). |
| /// - If the end iterator variable 'g' is defined, it is the same as 'j'. |
| /// - The container's iterators would not be invalidated during the loop. |
| StatementMatcher makePseudoArrayLoopMatcher() { |
| // Test that the incoming type has a record declaration that has methods |
| // called 'begin' and 'end'. If the incoming type is const, then make sure |
| // these methods are also marked const. |
| // |
| // FIXME: To be completely thorough this matcher should also ensure the |
| // return type of begin/end is an iterator that dereferences to the same as |
| // what operator[] or at() returns. Such a test isn't likely to fail except |
| // for pathological cases. |
| // |
| // FIXME: Also, a record doesn't necessarily need begin() and end(). Free |
| // functions called begin() and end() taking the container as an argument |
| // are also allowed. |
| TypeMatcher RecordWithBeginEnd = qualType( |
| anyOf(qualType(isConstQualified(), |
| hasDeclaration(recordDecl( |
| hasMethod(methodDecl(hasName("begin"), isConst())), |
| hasMethod(methodDecl(hasName("end"), |
| isConst())))) // hasDeclaration |
| ), // qualType |
| qualType(unless(isConstQualified()), |
| hasDeclaration( |
| recordDecl(hasMethod(hasName("begin")), |
| hasMethod(hasName("end"))))) // qualType |
| )); |
| |
| StatementMatcher SizeCallMatcher = memberCallExpr( |
| argumentCountIs(0), |
| callee(methodDecl(anyOf(hasName("size"), hasName("length")))), |
| on(anyOf(hasType(pointsTo(RecordWithBeginEnd)), |
| hasType(RecordWithBeginEnd)))); |
| |
| StatementMatcher EndInitMatcher = |
| expr(anyOf(ignoringParenImpCasts(expr(SizeCallMatcher).bind(EndCallName)), |
| explicitCastExpr(hasSourceExpression(ignoringParenImpCasts( |
| expr(SizeCallMatcher).bind(EndCallName)))))); |
| |
| DeclarationMatcher EndDeclMatcher = |
| varDecl(hasInitializer(EndInitMatcher)).bind(EndVarName); |
| |
| StatementMatcher IndexBoundMatcher = |
| expr(anyOf(ignoringParenImpCasts(declRefExpr(to( |
| varDecl(hasType(isInteger())).bind(ConditionEndVarName)))), |
| EndInitMatcher)); |
| |
| return forStmt( |
| hasLoopInit( |
| anyOf(declStmt(declCountIs(2), |
| containsDeclaration(0, InitToZeroMatcher), |
| containsDeclaration(1, EndDeclMatcher)), |
| declStmt(hasSingleDecl(InitToZeroMatcher)))), |
| hasCondition(anyOf( |
| binaryOperator(hasOperatorName("<"), |
| hasLHS(IntegerComparisonMatcher), |
| hasRHS(IndexBoundMatcher)), |
| binaryOperator(hasOperatorName(">"), hasLHS(IndexBoundMatcher), |
| hasRHS(IntegerComparisonMatcher)))), |
| hasIncrement(unaryOperator(hasOperatorName("++"), |
| hasUnaryOperand(IncrementVarMatcher)))) |
| .bind(LoopNamePseudoArray); |
| } |
| |
| /// \brief Determine whether Init appears to be an initializing an iterator. |
| /// |
| /// If it is, returns the object whose begin() or end() method is called, and |
| /// the output parameter isArrow is set to indicate whether the initialization |
| /// is called via . or ->. |
| static const Expr *getContainerFromBeginEndCall(const Expr *Init, bool IsBegin, |
| bool *IsArrow) { |
| // FIXME: Maybe allow declaration/initialization outside of the for loop. |
| const auto *TheCall = |
| dyn_cast_or_null<CXXMemberCallExpr>(digThroughConstructors(Init)); |
| if (!TheCall || TheCall->getNumArgs() != 0) |
| return nullptr; |
| |
| const auto *Member = dyn_cast<MemberExpr>(TheCall->getCallee()); |
| if (!Member) |
| return nullptr; |
| StringRef Name = Member->getMemberDecl()->getName(); |
| StringRef TargetName = IsBegin ? "begin" : "end"; |
| if (Name != TargetName) |
| return nullptr; |
| |
| const Expr *SourceExpr = Member->getBase(); |
| if (!SourceExpr) |
| return nullptr; |
| |
| *IsArrow = Member->isArrow(); |
| return SourceExpr; |
| } |
| |
| /// \brief Determines the container whose begin() and end() functions are called |
| /// for an iterator-based loop. |
| /// |
| /// BeginExpr must be a member call to a function named "begin()", and EndExpr |
| /// must be a member. |
| static const Expr *findContainer(ASTContext *Context, const Expr *BeginExpr, |
| const Expr *EndExpr, |
| bool *ContainerNeedsDereference) { |
| // Now that we know the loop variable and test expression, make sure they are |
| // valid. |
| bool BeginIsArrow = false; |
| bool EndIsArrow = false; |
| const Expr *BeginContainerExpr = |
| getContainerFromBeginEndCall(BeginExpr, /*IsBegin=*/true, &BeginIsArrow); |
| if (!BeginContainerExpr) |
| return nullptr; |
| |
| const Expr *EndContainerExpr = |
| getContainerFromBeginEndCall(EndExpr, /*IsBegin=*/false, &EndIsArrow); |
| // Disallow loops that try evil things like this (note the dot and arrow): |
| // for (IteratorType It = Obj.begin(), E = Obj->end(); It != E; ++It) { } |
| if (!EndContainerExpr || BeginIsArrow != EndIsArrow || |
| !areSameExpr(Context, EndContainerExpr, BeginContainerExpr)) |
| return nullptr; |
| |
| *ContainerNeedsDereference = BeginIsArrow; |
| return BeginContainerExpr; |
| } |
| |
| /// \brief Obtain the original source code text from a SourceRange. |
| static StringRef getStringFromRange(SourceManager &SourceMgr, |
| const LangOptions &LangOpts, |
| SourceRange Range) { |
| if (SourceMgr.getFileID(Range.getBegin()) != |
| SourceMgr.getFileID(Range.getEnd())) |
| return nullptr; |
| |
| return Lexer::getSourceText(CharSourceRange(Range, true), SourceMgr, |
| LangOpts); |
| } |
| |
| /// \brief If the given expression is actually a DeclRefExpr, find and return |
| /// the underlying VarDecl; otherwise, return NULL. |
| static const VarDecl *getReferencedVariable(const Expr *E) { |
| if (const DeclRefExpr *DRE = getDeclRef(E)) |
| return dyn_cast<VarDecl>(DRE->getDecl()); |
| return nullptr; |
| } |
| |
| /// \brief Returns true when the given expression is a member expression |
| /// whose base is `this` (implicitly or not). |
| static bool isDirectMemberExpr(const Expr *E) { |
| if (const auto *Member = dyn_cast<MemberExpr>(E->IgnoreParenImpCasts())) |
| return isa<CXXThisExpr>(Member->getBase()->IgnoreParenImpCasts()); |
| return false; |
| } |
| |
| LoopConvertCheck::LoopConvertCheck(StringRef Name, ClangTidyContext *Context) |
| : ClangTidyCheck(Name, Context), TUInfo(new TUTrackingInfo), |
| MinConfidence(StringSwitch<Confidence::Level>( |
| Options.get("MinConfidence", "reasonable")) |
| .Case("safe", Confidence::CL_Safe) |
| .Case("risky", Confidence::CL_Risky) |
| .Default(Confidence::CL_Reasonable)) {} |
| |
| void LoopConvertCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) { |
| SmallVector<std::string, 3> Confs{"risky", "reasonable", "safe"}; |
| Options.store(Opts, "MinConfidence", Confs[static_cast<int>(MinConfidence)]); |
| } |
| |
| /// \brief Computes the changes needed to convert a given for loop, and |
| /// applies it. |
| void LoopConvertCheck::doConversion( |
| ASTContext *Context, const VarDecl *IndexVar, const VarDecl *MaybeContainer, |
| StringRef ContainerString, const UsageResult &Usages, |
| const DeclStmt *AliasDecl, bool AliasUseRequired, bool AliasFromForInit, |
| const ForStmt *TheLoop, bool ContainerNeedsDereference, bool DerefByValue, |
| bool DerefByConstRef) { |
| auto Diag = diag(TheLoop->getForLoc(), "use range-based for loop instead"); |
| |
| std::string VarName; |
| bool VarNameFromAlias = (Usages.size() == 1) && AliasDecl; |
| bool AliasVarIsRef = false; |
| |
| if (VarNameFromAlias) { |
| const auto *AliasVar = cast<VarDecl>(AliasDecl->getSingleDecl()); |
| VarName = AliasVar->getName().str(); |
| AliasVarIsRef = AliasVar->getType()->isReferenceType(); |
| |
| // We keep along the entire DeclStmt to keep the correct range here. |
| const SourceRange &ReplaceRange = AliasDecl->getSourceRange(); |
| |
| std::string ReplacementText; |
| if (AliasUseRequired) { |
| ReplacementText = VarName; |
| } else if (AliasFromForInit) { |
| // FIXME: Clang includes the location of the ';' but only for DeclStmt's |
| // in a for loop's init clause. Need to put this ';' back while removing |
| // the declaration of the alias variable. This is probably a bug. |
| ReplacementText = ";"; |
| } |
| |
| Diag << FixItHint::CreateReplacement( |
| CharSourceRange::getTokenRange(ReplaceRange), ReplacementText); |
| // No further replacements are made to the loop, since the iterator or index |
| // was used exactly once - in the initialization of AliasVar. |
| } else { |
| VariableNamer Namer(&TUInfo->getGeneratedDecls(), |
| &TUInfo->getParentFinder().getStmtToParentStmtMap(), |
| TheLoop, IndexVar, MaybeContainer, Context); |
| VarName = Namer.createIndexName(); |
| // First, replace all usages of the array subscript expression with our new |
| // variable. |
| for (const auto &I : Usages) { |
| StringRef ReplaceText = I.IsArrow ? VarName + "." : VarName; |
| TUInfo->getReplacedVars().insert(std::make_pair(TheLoop, IndexVar)); |
| Diag << FixItHint::CreateReplacement( |
| CharSourceRange::getTokenRange(I.Range), ReplaceText); |
| } |
| } |
| |
| // Now, we need to construct the new range expression. |
| SourceRange ParenRange(TheLoop->getLParenLoc(), TheLoop->getRParenLoc()); |
| |
| QualType AutoRefType = Context->getAutoDeductType(); |
| |
| // If the new variable name is from the aliased variable, then the reference |
| // type for the new variable should only be used if the aliased variable was |
| // declared as a reference. |
| if (!VarNameFromAlias || AliasVarIsRef) { |
| // If an iterator's operator*() returns a 'T&' we can bind that to 'auto&'. |
| // If operator*() returns 'T' we can bind that to 'auto&&' which will deduce |
| // to 'T&&&'. |
| if (DerefByValue) { |
| AutoRefType = Context->getRValueReferenceType(AutoRefType); |
| } else { |
| if (DerefByConstRef) |
| AutoRefType = Context->getConstType(AutoRefType); |
| AutoRefType = Context->getLValueReferenceType(AutoRefType); |
| } |
| } |
| |
| StringRef MaybeDereference = ContainerNeedsDereference ? "*" : ""; |
| StringRef TypeString = AutoRefType.getAsString(); |
| StringRef Range = ("(" + TypeString + " " + VarName + " : " + |
| MaybeDereference + ContainerString + ")") |
| .str(); |
| |
| Diag << FixItHint::CreateReplacement( |
| CharSourceRange::getTokenRange(ParenRange), Range); |
| TUInfo->getGeneratedDecls().insert(make_pair(TheLoop, VarName)); |
| } |
| |
| /// \brief Determine if the change should be deferred or rejected, returning |
| /// text which refers to the container iterated over if the change should |
| /// proceed. |
| StringRef LoopConvertCheck::checkRejections(ASTContext *Context, |
| const Expr *ContainerExpr, |
| const ForStmt *TheLoop) { |
| // If we already modified the reange of this for loop, don't do any further |
| // updates on this iteration. |
| if (TUInfo->getReplacedVars().count(TheLoop)) |
| return ""; |
| |
| Context->getTranslationUnitDecl(); |
| TUInfo->getParentFinder(); |
| TUInfo->getParentFinder().gatherAncestors(Context->getTranslationUnitDecl()); |
| // Ensure that we do not try to move an expression dependent on a local |
| // variable declared inside the loop outside of it. |
| DependencyFinderASTVisitor DependencyFinder( |
| &TUInfo->getParentFinder().getStmtToParentStmtMap(), |
| &TUInfo->getParentFinder().getDeclToParentStmtMap(), |
| &TUInfo->getReplacedVars(), TheLoop); |
| |
| // FIXME: Determine when the external dependency isn't an expression converted |
| // by another loop. |
| if (DependencyFinder.dependsOnInsideVariable(ContainerExpr)) |
| return ""; |
| |
| StringRef ContainerString; |
| if (isa<CXXThisExpr>(ContainerExpr->IgnoreParenImpCasts())) { |
| ContainerString = "this"; |
| } else { |
| ContainerString = |
| getStringFromRange(Context->getSourceManager(), Context->getLangOpts(), |
| ContainerExpr->getSourceRange()); |
| } |
| |
| return ContainerString; |
| } |
| |
| /// \brief Given a loop header that would be convertible, discover all usages |
| /// of the index variable and convert the loop if possible. |
| void LoopConvertCheck::findAndVerifyUsages( |
| ASTContext *Context, const VarDecl *LoopVar, const VarDecl *EndVar, |
| const Expr *ContainerExpr, const Expr *BoundExpr, |
| bool ContainerNeedsDereference, bool DerefByValue, bool DerefByConstRef, |
| const ForStmt *TheLoop, LoopFixerKind FixerKind) { |
| ForLoopIndexUseVisitor Finder(Context, LoopVar, EndVar, ContainerExpr, |
| BoundExpr, ContainerNeedsDereference); |
| |
| if (ContainerExpr) { |
| ComponentFinderASTVisitor ComponentFinder; |
| ComponentFinder.findExprComponents(ContainerExpr->IgnoreParenImpCasts()); |
| Finder.addComponents(ComponentFinder.getComponents()); |
| } |
| |
| if (!Finder.findAndVerifyUsages(TheLoop->getBody())) |
| return; |
| |
| Confidence ConfidenceLevel(Finder.getConfidenceLevel()); |
| if (FixerKind == LFK_Array) { |
| // The array being indexed by IndexVar was discovered during traversal. |
| ContainerExpr = Finder.getContainerIndexed()->IgnoreParenImpCasts(); |
| // Very few loops are over expressions that generate arrays rather than |
| // array variables. Consider loops over arrays that aren't just represented |
| // by a variable to be risky conversions. |
| if (!getReferencedVariable(ContainerExpr) && |
| !isDirectMemberExpr(ContainerExpr)) |
| ConfidenceLevel.lowerTo(Confidence::CL_Risky); |
| } |
| |
| StringRef ContainerString = checkRejections(Context, ContainerExpr, TheLoop); |
| |
| if (ContainerString.empty() || ConfidenceLevel.getLevel() < MinConfidence) |
| return; |
| |
| doConversion(Context, LoopVar, getReferencedVariable(ContainerExpr), |
| ContainerString, Finder.getUsages(), Finder.getAliasDecl(), |
| Finder.aliasUseRequired(), Finder.aliasFromForInit(), TheLoop, |
| ContainerNeedsDereference, DerefByValue, DerefByConstRef); |
| } |
| |
| void LoopConvertCheck::registerMatchers(MatchFinder *Finder) { |
| Finder->addMatcher(makeArrayLoopMatcher(), this); |
| Finder->addMatcher(makeIteratorLoopMatcher(), this); |
| Finder->addMatcher(makePseudoArrayLoopMatcher(), this); |
| } |
| |
| void LoopConvertCheck::check(const MatchFinder::MatchResult &Result) { |
| const BoundNodes &Nodes = Result.Nodes; |
| Confidence ConfidenceLevel(Confidence::CL_Safe); |
| ASTContext *Context = Result.Context; |
| |
| const ForStmt *TheLoop; |
| LoopFixerKind FixerKind; |
| |
| if ((TheLoop = Nodes.getStmtAs<ForStmt>(LoopNameArray))) { |
| FixerKind = LFK_Array; |
| } else if ((TheLoop = Nodes.getStmtAs<ForStmt>(LoopNameIterator))) { |
| FixerKind = LFK_Iterator; |
| } else { |
| TheLoop = Nodes.getStmtAs<ForStmt>(LoopNamePseudoArray); |
| assert(TheLoop && "Bad Callback. No for statement"); |
| FixerKind = LFK_PseudoArray; |
| } |
| |
| // Check that we have exactly one index variable and at most one end variable. |
| const auto *LoopVar = Nodes.getDeclAs<VarDecl>(IncrementVarName); |
| const auto *CondVar = Nodes.getDeclAs<VarDecl>(ConditionVarName); |
| const auto *InitVar = Nodes.getDeclAs<VarDecl>(InitVarName); |
| if (!areSameVariable(LoopVar, CondVar) || !areSameVariable(LoopVar, InitVar)) |
| return; |
| const auto *EndVar = Nodes.getDeclAs<VarDecl>(EndVarName); |
| const auto *ConditionEndVar = Nodes.getDeclAs<VarDecl>(ConditionEndVarName); |
| if (EndVar && !areSameVariable(EndVar, ConditionEndVar)) |
| return; |
| |
| // If the end comparison isn't a variable, we can try to work with the |
| // expression the loop variable is being tested against instead. |
| const auto *EndCall = Nodes.getStmtAs<CXXMemberCallExpr>(EndCallName); |
| const auto *BoundExpr = Nodes.getStmtAs<Expr>(ConditionBoundName); |
| // If the loop calls end()/size() after each iteration, lower our confidence |
| // level. |
| if (FixerKind != LFK_Array && !EndVar) |
| ConfidenceLevel.lowerTo(Confidence::CL_Reasonable); |
| |
| const Expr *ContainerExpr = nullptr; |
| bool DerefByValue = false; |
| bool DerefByConstRef = false; |
| bool ContainerNeedsDereference = false; |
| // FIXME: Try to put most of this logic inside a matcher. Currently, matchers |
| // don't allow the ight-recursive checks in digThroughConstructors. |
| if (FixerKind == LFK_Iterator) { |
| ContainerExpr = findContainer(Context, LoopVar->getInit(), |
| EndVar ? EndVar->getInit() : EndCall, |
| &ContainerNeedsDereference); |
| |
| QualType InitVarType = InitVar->getType(); |
| QualType CanonicalInitVarType = InitVarType.getCanonicalType(); |
| |
| const auto *BeginCall = Nodes.getNodeAs<CXXMemberCallExpr>(BeginCallName); |
| assert(BeginCall && "Bad Callback. No begin call expression"); |
| QualType CanonicalBeginType = |
| BeginCall->getMethodDecl()->getReturnType().getCanonicalType(); |
| if (CanonicalBeginType->isPointerType() && |
| CanonicalInitVarType->isPointerType()) { |
| QualType BeginPointeeType = CanonicalBeginType->getPointeeType(); |
| QualType InitPointeeType = CanonicalInitVarType->getPointeeType(); |
| // If the initializer and the variable are both pointers check if the |
| // un-qualified pointee types match otherwise we don't use auto. |
| if (!Context->hasSameUnqualifiedType(InitPointeeType, BeginPointeeType)) |
| return; |
| } else { |
| // Check for qualified types to avoid conversions from non-const to const |
| // iterator types. |
| if (!Context->hasSameType(CanonicalInitVarType, CanonicalBeginType)) |
| return; |
| } |
| |
| DerefByValue = Nodes.getNodeAs<QualType>(DerefByValueResultName) != nullptr; |
| if (!DerefByValue) { |
| if (const auto *DerefType = |
| Nodes.getNodeAs<QualType>(DerefByRefResultName)) { |
| // A node will only be bound with DerefByRefResultName if we're dealing |
| // with a user-defined iterator type. Test the const qualification of |
| // the reference type. |
| DerefByConstRef = (*DerefType) |
| ->getAs<ReferenceType>() |
| ->getPointeeType() |
| .isConstQualified(); |
| } else { |
| // By nature of the matcher this case is triggered only for built-in |
| // iterator types (i.e. pointers). |
| assert(isa<PointerType>(CanonicalInitVarType) && |
| "Non-class iterator type is not a pointer type"); |
| QualType InitPointeeType = CanonicalInitVarType->getPointeeType(); |
| QualType BeginPointeeType = CanonicalBeginType->getPointeeType(); |
| // If the initializer and variable have both the same type just use auto |
| // otherwise we test for const qualification of the pointed-at type. |
| if (!Context->hasSameType(InitPointeeType, BeginPointeeType)) |
| DerefByConstRef = InitPointeeType.isConstQualified(); |
| } |
| } else { |
| // If the dereference operator returns by value then test for the |
| // canonical const qualification of the init variable type. |
| DerefByConstRef = CanonicalInitVarType.isConstQualified(); |
| } |
| } else if (FixerKind == LFK_PseudoArray) { |
| if (!EndCall) |
| return; |
| ContainerExpr = EndCall->getImplicitObjectArgument(); |
| const auto *Member = dyn_cast<MemberExpr>(EndCall->getCallee()); |
| if (!Member) |
| return; |
| ContainerNeedsDereference = Member->isArrow(); |
| } |
| |
| // We must know the container or an array length bound. |
| if (!ContainerExpr && !BoundExpr) |
| return; |
| |
| if (ConfidenceLevel.getLevel() < MinConfidence) |
| return; |
| |
| findAndVerifyUsages(Context, LoopVar, EndVar, ContainerExpr, BoundExpr, |
| ContainerNeedsDereference, DerefByValue, DerefByConstRef, |
| TheLoop, FixerKind); |
| } |
| |
| } // namespace modernize |
| } // namespace tidy |
| } // namespace clang |