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llvm-project/clang-tools-extra/clang-tidy/modernize/LoopConvertCheck.cpp

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//===--- 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(
unless(isInTemplateInstantiation()),
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(
unless(isInTemplateInstantiation()),
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(
unless(isInTemplateInstantiation()),
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 StringRef(); // Empty string.
}
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) {
std::string 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 ? "*" : "";
std::string TypeString = AutoRefType.getAsString();
std::string 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) {
// Only register the matchers for C++. Because this checker is used for
// modernization, it is reasonable to run it on any C++ standard with the
// assumption the user is trying to modernize their codebase.
if (getLangOpts().CPlusPlus) {
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
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