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//===--- UseEmplaceCheck.cpp - clang-tidy----------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#include "UseEmplaceCheck.h"
#include "../utils/OptionsUtils.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace modernize {
namespace {
AST_MATCHER(DeclRefExpr, hasExplicitTemplateArgs) {
return Node.hasExplicitTemplateArgs();
}
const auto DefaultContainersWithPushBack =
"::std::vector; ::std::list; ::std::deque";
const auto DefaultSmartPointers =
"::std::shared_ptr; ::std::unique_ptr; ::std::auto_ptr; ::std::weak_ptr";
const auto DefaultTupleTypes = "::std::pair; ::std::tuple";
const auto DefaultTupleMakeFunctions = "::std::make_pair; ::std::make_tuple";
} // namespace
UseEmplaceCheck::UseEmplaceCheck(StringRef Name, ClangTidyContext *Context)
: ClangTidyCheck(Name, Context), IgnoreImplicitConstructors(Options.get(
"IgnoreImplicitConstructors", false)),
ContainersWithPushBack(utils::options::parseStringList(Options.get(
"ContainersWithPushBack", DefaultContainersWithPushBack))),
SmartPointers(utils::options::parseStringList(
Options.get("SmartPointers", DefaultSmartPointers))),
TupleTypes(utils::options::parseStringList(
Options.get("TupleTypes", DefaultTupleTypes))),
TupleMakeFunctions(utils::options::parseStringList(
Options.get("TupleMakeFunctions", DefaultTupleMakeFunctions))) {}
void UseEmplaceCheck::registerMatchers(MatchFinder *Finder) {
// FIXME: Bunch of functionality that could be easily added:
// + add handling of `push_front` for std::forward_list, std::list
// and std::deque.
// + add handling of `push` for std::stack, std::queue, std::priority_queue
// + add handling of `insert` for stl associative container, but be careful
// because this requires special treatment (it could cause performance
// regression)
// + match for emplace calls that should be replaced with insertion
auto CallPushBack = cxxMemberCallExpr(
hasDeclaration(functionDecl(hasName("push_back"))),
on(hasType(cxxRecordDecl(hasAnyName(SmallVector<StringRef, 5>(
ContainersWithPushBack.begin(), ContainersWithPushBack.end()))))));
// We can't replace push_backs of smart pointer because
// if emplacement fails (f.e. bad_alloc in vector) we will have leak of
// passed pointer because smart pointer won't be constructed
// (and destructed) as in push_back case.
auto IsCtorOfSmartPtr = hasDeclaration(cxxConstructorDecl(ofClass(hasAnyName(
SmallVector<StringRef, 5>(SmartPointers.begin(), SmartPointers.end())))));
// Bitfields binds only to consts and emplace_back take it by universal ref.
auto BitFieldAsArgument = hasAnyArgument(
ignoringImplicit(memberExpr(hasDeclaration(fieldDecl(isBitField())))));
// Initializer list can't be passed to universal reference.
auto InitializerListAsArgument = hasAnyArgument(
ignoringImplicit(cxxConstructExpr(isListInitialization())));
// We could have leak of resource.
auto NewExprAsArgument = hasAnyArgument(ignoringImplicit(cxxNewExpr()));
// We would call another constructor.
auto ConstructingDerived =
hasParent(implicitCastExpr(hasCastKind(CastKind::CK_DerivedToBase)));
// emplace_back can't access private constructor.
auto IsPrivateCtor = hasDeclaration(cxxConstructorDecl(isPrivate()));
auto HasInitList = anyOf(has(ignoringImplicit(initListExpr())),
has(cxxStdInitializerListExpr()));
// FIXME: Discard 0/NULL (as nullptr), static inline const data members,
// overloaded functions and template names.
auto SoughtConstructExpr =
cxxConstructExpr(
unless(anyOf(IsCtorOfSmartPtr, HasInitList, BitFieldAsArgument,
InitializerListAsArgument, NewExprAsArgument,
ConstructingDerived, IsPrivateCtor)))
.bind("ctor");
auto HasConstructExpr = has(ignoringImplicit(SoughtConstructExpr));
auto MakeTuple = ignoringImplicit(
callExpr(
callee(expr(ignoringImplicit(declRefExpr(
unless(hasExplicitTemplateArgs()),
to(functionDecl(hasAnyName(SmallVector<StringRef, 2>(
TupleMakeFunctions.begin(), TupleMakeFunctions.end())))))))))
.bind("make"));
// make_something can return type convertible to container's element type.
// Allow the conversion only on containers of pairs.
auto MakeTupleCtor = ignoringImplicit(cxxConstructExpr(
has(materializeTemporaryExpr(MakeTuple)),
hasDeclaration(cxxConstructorDecl(ofClass(hasAnyName(
SmallVector<StringRef, 2>(TupleTypes.begin(), TupleTypes.end())))))));
auto SoughtParam = materializeTemporaryExpr(
anyOf(has(MakeTuple), has(MakeTupleCtor),
HasConstructExpr, has(cxxFunctionalCastExpr(HasConstructExpr))));
Finder->addMatcher(
traverse(TK_AsIs, cxxMemberCallExpr(CallPushBack, has(SoughtParam),
unless(isInTemplateInstantiation()))
.bind("call")),
this);
}
void UseEmplaceCheck::check(const MatchFinder::MatchResult &Result) {
const auto *Call = Result.Nodes.getNodeAs<CXXMemberCallExpr>("call");
const auto *CtorCall = Result.Nodes.getNodeAs<CXXConstructExpr>("ctor");
const auto *MakeCall = Result.Nodes.getNodeAs<CallExpr>("make");
assert((CtorCall || MakeCall) && "No push_back parameter matched");
if (IgnoreImplicitConstructors && CtorCall && CtorCall->getNumArgs() >= 1 &&
CtorCall->getArg(0)->getSourceRange() == CtorCall->getSourceRange())
return;
const auto FunctionNameSourceRange = CharSourceRange::getCharRange(
Call->getExprLoc(), Call->getArg(0)->getExprLoc());
auto Diag = diag(Call->getExprLoc(), "use emplace_back instead of push_back");
if (FunctionNameSourceRange.getBegin().isMacroID())
return;
const auto *EmplacePrefix = MakeCall ? "emplace_back" : "emplace_back(";
Diag << FixItHint::CreateReplacement(FunctionNameSourceRange, EmplacePrefix);
const SourceRange CallParensRange =
MakeCall ? SourceRange(MakeCall->getCallee()->getEndLoc(),
MakeCall->getRParenLoc())
: CtorCall->getParenOrBraceRange();
// Finish if there is no explicit constructor call.
if (CallParensRange.getBegin().isInvalid())
return;
const SourceLocation ExprBegin =
MakeCall ? MakeCall->getExprLoc() : CtorCall->getExprLoc();
// Range for constructor name and opening brace.
const auto ParamCallSourceRange =
CharSourceRange::getTokenRange(ExprBegin, CallParensRange.getBegin());
Diag << FixItHint::CreateRemoval(ParamCallSourceRange)
<< FixItHint::CreateRemoval(CharSourceRange::getTokenRange(
CallParensRange.getEnd(), CallParensRange.getEnd()));
}
void UseEmplaceCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
Options.store(Opts, "IgnoreImplicitConstructors", IgnoreImplicitConstructors);
Options.store(Opts, "ContainersWithPushBack",
utils::options::serializeStringList(ContainersWithPushBack));
Options.store(Opts, "SmartPointers",
utils::options::serializeStringList(SmartPointers));
Options.store(Opts, "TupleTypes",
utils::options::serializeStringList(TupleTypes));
Options.store(Opts, "TupleMakeFunctions",
utils::options::serializeStringList(TupleMakeFunctions));
}
} // namespace modernize
} // namespace tidy
} // namespace clang
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