Index: clang-tidy/modernize/CMakeLists.txt =================================================================== --- clang-tidy/modernize/CMakeLists.txt +++ clang-tidy/modernize/CMakeLists.txt @@ -20,6 +20,7 @@ UseEmplaceCheck.cpp UseNullptrCheck.cpp UseOverrideCheck.cpp + UseTransparentFunctorsCheck.cpp UseUsingCheck.cpp LINK_LIBS Index: clang-tidy/modernize/ModernizeTidyModule.cpp =================================================================== --- clang-tidy/modernize/ModernizeTidyModule.cpp +++ clang-tidy/modernize/ModernizeTidyModule.cpp @@ -26,6 +26,7 @@ #include "UseEmplaceCheck.h" #include "UseNullptrCheck.h" #include "UseOverrideCheck.h" +#include "UseTransparentFunctorsCheck.h" #include "UseUsingCheck.h" using namespace clang::ast_matchers; @@ -59,6 +60,8 @@ CheckFactories.registerCheck("modernize-use-emplace"); CheckFactories.registerCheck("modernize-use-nullptr"); CheckFactories.registerCheck("modernize-use-override"); + CheckFactories.registerCheck( + "modernize-use-transparent-functors"); CheckFactories.registerCheck("modernize-use-using"); } Index: clang-tidy/modernize/UseTransparentFunctorsCheck.h =================================================================== --- /dev/null +++ clang-tidy/modernize/UseTransparentFunctorsCheck.h @@ -0,0 +1,35 @@ +//===--- UseTransparentFunctorsCheck.h - clang-tidy--------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_TRANSPARENT_FUNCTORS_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_TRANSPARENT_FUNCTORS_H + +#include "../ClangTidy.h" + +namespace clang { +namespace tidy { +namespace modernize { + +/// Prefer using transparent functors to non-transparent ones. +/// +/// For the user-facing documentation see: +/// http://clang.llvm.org/extra/clang-tidy/checks/modernize-use-transparent-functors.html +class UseTransparentFunctorsCheck : public ClangTidyCheck { +public: + UseTransparentFunctorsCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; +}; + +} // namespace modernize +} // namespace tidy +} // namespace clang + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USE_TRANSPARENT_FUNCTORS_H Index: clang-tidy/modernize/UseTransparentFunctorsCheck.cpp =================================================================== --- /dev/null +++ clang-tidy/modernize/UseTransparentFunctorsCheck.cpp @@ -0,0 +1,99 @@ +//===--- UseTransparentFunctorsCheck.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 "UseTransparentFunctorsCheck.h" +#include "clang/AST/ASTContext.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" + +using namespace clang::ast_matchers; + +namespace clang { +namespace tidy { +namespace modernize { + +void UseTransparentFunctorsCheck::registerMatchers(MatchFinder *Finder) { + if (!getLangOpts().CPlusPlus14) + return; + + const auto TransparentFunctors = classTemplateSpecializationDecl( + unless(hasAnyTemplateArgument(refersToType(voidType()))), + hasAnyName("::std::plus", "::std::minus", "::std::multiplies", + "::std::divides", "::std::modulus", "::std::negate", + "::std::equal_to", "::std::not_equal_to", "::std::greater", + "::std::less", "::std::greater_equal", "::std::less_equal", + "::std::logical_and", "::std::logical_or", + "::std::logical_not", "::std::bit_and", "::std::bit_or", + "::std::bit_xor", "::std::bit_not")); + + // Non-transparent functor mentioned as a template parameter. FIXIT. + Finder->addMatcher( + loc(qualType( + unless(elaboratedType()), + hasDeclaration(classTemplateSpecializationDecl( + unless(hasAnyTemplateArgument(templateArgument(refersToType( + qualType(pointsTo(qualType(isAnyCharacter()))))))), + hasAnyTemplateArgument( + templateArgument(refersToType(qualType(hasDeclaration( + TransparentFunctors)))) + .bind("Functor")))))) + .bind("FunctorParentLoc"), + this); + + // Non-transparent functor constructed. No FIXIT. There is no easy way + // to rule out the problematic char* vs string case. + Finder->addMatcher(cxxConstructExpr(hasDeclaration(cxxMethodDecl( + ofClass(TransparentFunctors))), + unless(isInTemplateInstantiation())) + .bind("FuncInst"), + this); +} + +void UseTransparentFunctorsCheck::check( + const MatchFinder::MatchResult &Result) { + if (const auto *FuncInst = + Result.Nodes.getNodeAs("FuncInst")) { + diag(FuncInst->getLocStart(), "prefer transparent functors"); + return; + } + + const auto *Functor = Result.Nodes.getNodeAs("Functor"); + const auto FunctorParentLoc = + Result.Nodes.getNodeAs("FunctorParentLoc") + ->castAs(); + + unsigned ArgNum = 0; + for (; ArgNum < FunctorParentLoc.getNumArgs(); ++ArgNum) { + if (FunctorParentLoc.getArgLoc(ArgNum) + .getArgument() + .getAsType() + .getDesugaredType(*Result.Context) == Functor->getAsType()) { + break; + } + } + assert(ArgNum < FunctorParentLoc.getNumArgs()); + TemplateArgumentLoc FunctorLoc = FunctorParentLoc.getArgLoc(ArgNum); + auto FunctorTypeLoc = FunctorLoc.getTypeSourceInfo() + ->getTypeLoc() + .getAs(); + if (FunctorTypeLoc.isNull()) { + FunctorTypeLoc = FunctorLoc.getTypeSourceInfo() + ->getTypeLoc() + .getAs() + .getNamedTypeLoc() + .castAs(); + } + SourceLocation ReportLoc = FunctorLoc.getLocation(); + + diag(ReportLoc, "prefer transparent functors") + << FixItHint::CreateRemoval(FunctorTypeLoc.getArgLoc(0).getSourceRange()); +} + +} // namespace modernize +} // namespace tidy +} // namespace clang Index: docs/ReleaseNotes.rst =================================================================== --- docs/ReleaseNotes.rst +++ docs/ReleaseNotes.rst @@ -79,6 +79,11 @@ Warns if an object is used after it has been moved, without an intervening reinitialization. +- New `modernize-use-transparent-functors + `_ check + + Replaces uses of non-transparent functors with transparent ones where applicable. + - New `mpi-buffer-deref `_ check Index: docs/clang-tidy/checks/list.rst =================================================================== --- docs/clang-tidy/checks/list.rst +++ docs/clang-tidy/checks/list.rst @@ -111,6 +111,7 @@ modernize-use-emplace modernize-use-nullptr modernize-use-override + modernize-use-transparent-functors modernize-use-using mpi-buffer-deref mpi-type-mismatch Index: docs/clang-tidy/checks/modernize-use-transparent-functors.rst =================================================================== --- /dev/null +++ docs/clang-tidy/checks/modernize-use-transparent-functors.rst @@ -0,0 +1,24 @@ +.. title:: clang-tidy - modernize-use-transparent-functors + +modernize-use-transparent-functors +================================== + +Prefer transparent functors to non-transparent ones. Using transparent functors +the type does not need to be repeated. The code is easier to read, maintain and +less prone to errors. It not possible to introduce unwanted conversions. + + .. code-block:: c++ + + // Non-transparent functor + std::map> s; + + // Transparent functor. + std::map> s; + +It is not always a safe transformation though. The following case will be +untouched to preserve the semantics. + + .. code-block:: c++ + + // Non-transparent functor + std::map> s; Index: test/clang-tidy/modernize-use-transparent-functors.cpp =================================================================== --- /dev/null +++ test/clang-tidy/modernize-use-transparent-functors.cpp @@ -0,0 +1,100 @@ +// RUN: %check_clang_tidy %s modernize-use-transparent-functors %t -- -- -std=c++14 + +namespace std { +template +struct remove_reference; + +template +constexpr T &&forward(typename std::remove_reference::type &t); + +template +constexpr T &&forward(typename std::remove_reference::type &&t); + +template +struct plus { + constexpr T operator()(const T &Lhs, const T &Rhs) const; +}; + +template <> +struct plus { + template + constexpr auto operator()(T &&Lhs, U &&Rhs) const -> + decltype(forward(Lhs) + forward(Rhs)); +}; + +template +struct less { + constexpr bool operator()(const T &Lhs, const T &Rhs) const; +}; + +template <> +struct less { + template + constexpr bool operator()(T &&Lhs, U &&Rhs) const; +}; + +template +struct logical_not { + constexpr bool operator()(const T &Arg) const; +}; + +template <> +struct logical_not { + template + constexpr bool operator()(T &&Arg) const; +}; + +template +class allocator; + +template < + class Key, + class Compare = std::less<>, + class Allocator = std::allocator> +class set {}; + +template +InputIt find_if(InputIt first, InputIt last, + UnaryPredicate p); + +template +void sort(RandomIt first, RandomIt last, Compare comp); + +class iterator {}; +class string {}; +} + +int main() { + using std::set; + using std::less; + std::set> s; + // CHECK-MESSAGES: :[[@LINE-1]]:17: warning: prefer transparent functors [modernize-use-transparent-functors] + // CHECK-FIXES: {{^}} std::set> s;{{$}} + set> s2; + // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: prefer transparent functors + // CHECK-FIXES: {{^}} set> s2;{{$}} + set> s3; + // CHECK-MESSAGES: :[[@LINE-1]]:12: warning: prefer transparent functors + // CHECK-FIXES: {{^}} set> s3;{{$}} + std::set> s4; + std::set> s5; + std::set>, std::less<>> s6; + // CHECK-MESSAGES: :[[@LINE-1]]:21: warning: prefer transparent functors + // CHECK-FIXES: {{^}} std::set>, std::less<>> s6;{{$}} + std::iterator begin, end; + sort(begin, end, std::less()); + // CHECK-MESSAGES: :[[@LINE-1]]:20: warning: prefer transparent functors + std::sort(begin, end, std::less<>()); + find_if(begin, end, std::logical_not()); + // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: prefer transparent functors + std::find_if(begin, end, std::logical_not<>()); + using my_set = std::set>; + // CHECK-MESSAGES: :[[@LINE-1]]:32: warning: prefer transparent functors + // CHECK-FIXES: {{^}} using my_set = std::set>;{{$}} + using my_set2 = std::set>; + using my_less = std::less; + find_if(begin, end, my_less()); + // CHECK-MESSAGES: :[[@LINE-1]]:23: warning: prefer transparent functors +} + +