bernhardmgruber updated this revision to Diff 179986. bernhardmgruber added a comment.
rebased from release_70 onto master CHANGES SINCE LAST ACTION https://reviews.llvm.org/D56160/new/ https://reviews.llvm.org/D56160 Files: clang-tidy/modernize/CMakeLists.txt clang-tidy/modernize/ModernizeTidyModule.cpp clang-tidy/modernize/UseTrailingReturnCheck.cpp clang-tidy/modernize/UseTrailingReturnCheck.h docs/ReleaseNotes.rst docs/clang-tidy/checks/list.rst docs/clang-tidy/checks/modernize-use-trailing-return.rst test/clang-tidy/modernize-use-trailing-return.cpp
Index: test/clang-tidy/modernize-use-trailing-return.cpp =================================================================== --- /dev/null +++ test/clang-tidy/modernize-use-trailing-return.cpp @@ -0,0 +1,173 @@ +// RUN: %check_clang_tidy %s modernize-use-trailing-return %t -- -- --std=c++14 + +namespace std { + template <typename T> + class vector; + + class string; +} + +// +// Samples triggering the check +// + +int f(); +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto f() -> int;{{$}} +int f(int); +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto f(int) -> int;{{$}} +int f(int arg); +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto f(int arg) -> int;{{$}} +int f(int arg1, int arg2, int arg3); +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto f(int arg1, int arg2, int arg3) -> int;{{$}} +int f(int arg1, int arg2, int arg3, ...); +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto f(int arg1, int arg2, int arg3, ...) -> int;{{$}} +template <typename T> int f(T t); +// CHECK-MESSAGES: :[[@LINE-1]]:27: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}template <typename T> auto f(T t) -> int;{{$}} +int a1() { return 42; } +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto a1() -> int { return 42; }{{$}} +int a2() { + return 42; +} +// CHECK-MESSAGES: :[[@LINE-3]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto a2() -> int {{{$}} +int a3() +{ + return 42; +} +// CHECK-MESSAGES: :[[@LINE-4]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto a3() -> int{{$}} +int b1(int arg ) ; +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto b1(int arg ) -> int ;{{$}} +int b2 +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto b2{{$}} +(int arg); +// CHECK-FIXES: {{^}}(int arg) -> int;{{$}} +inline int d1(int arg); +// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}inline auto d1(int arg) -> int;{{$}} +inline int d2(int arg) noexcept(true); +// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}inline auto d2(int arg) -> int noexcept(true);{{$}} +inline int d3(int arg) try { } catch(...) { } +// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}inline auto d3(int arg) -> int try { } catch(...) { }{{$}} +namespace N { + bool e1(); +} +// CHECK-MESSAGES: :[[@LINE-2]]:10: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} auto e1() -> bool;{{$}} +inline volatile const std::vector<std::string> e2(); +// CHECK-MESSAGES: :[[@LINE-1]]:48: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}inline auto e2() -> volatile const std::vector<std::string>;{{$}} +inline const std::vector<std::string> volatile e2(); +// CHECK-MESSAGES: :[[@LINE-1]]:48: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}inline auto e2() -> const std::vector<std::string> volatile;{{$}} +inline std::vector<std::string> const volatile e2(); +// CHECK-MESSAGES: :[[@LINE-1]]:48: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}inline auto e2() -> std::vector<std::string> const volatile;{{$}} +bool N::e1() {} +// CHECK-MESSAGES: :[[@LINE-1]]:9: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto N::e1() -> bool {}{{$}} +int (*e3())(double); +// CHECK-MESSAGES: :[[@LINE-1]]:7: warning: use a trailing return type for this function (FixIt not implemented) [modernize-use-trailing-return] +// TODO: not matched by the AST matcher +//decltype(auto) e4(); +// _HECK-MESSAGES: :[[@LINE-1]]:16: warning: use a trailing return type for this function [modernize-use-trailing-return] +// _HECK-FIXES: {{^}}auto e4() -> decltype(auto);{{$}} + +struct B { + B& operator=(const B&); +// CHECK-MESSAGES: :[[@LINE-1]]:8: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} auto operator=(const B&) -> B&;{{$}} + + double base1(int, bool b); +// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} auto base1(int, bool b) -> double;{{$}} + + virtual double base2(int, bool b) {} +// CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} virtual auto base2(int, bool b) -> double {}{{$}} + + virtual float base3() const = 0; +// CHECK-MESSAGES: :[[@LINE-1]]:19: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} virtual auto base3() const -> float = 0;{{$}} + + double base4(int, bool b) &&; +// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} auto base4(int, bool b) && -> double;{{$}} + + double base5(int, bool b) const &&; +// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} auto base5(int, bool b) const && -> double;{{$}} + + double base6(int, bool b) const & = delete; +// CHECK-MESSAGES: :[[@LINE-1]]:12: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} auto base6(int, bool b) const & -> double = delete;{{$}} +}; + +double B::base1(int, bool b) {} +// CHECK-MESSAGES: :[[@LINE-1]]:11: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto B::base1(int, bool b) -> double {}{{$}} + +struct D : B { + virtual double f1(int, bool b) final; +// CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} virtual auto f1(int, bool b) -> double final;{{$}} + + virtual double base2(int, bool b) override; +// CHECK-MESSAGES: :[[@LINE-1]]:20: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} virtual auto base2(int, bool b) -> double override;{{$}} + + virtual float base3() const override final { } +// CHECK-MESSAGES: :[[@LINE-1]]:19: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}} virtual auto base3() const -> float override final { }{{$}} +}; + +int g1() [[asdf]]; +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto g1() -> int {{[[][[]}}asdf{{[]][]]}};{{$}} +[[noreturn]] int g2(); +// CHECK-MESSAGES: :[[@LINE-1]]:18: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}{{[[][[]}}noreturn{{[]][]]}} auto g2() -> int;{{$}} +int g2 [[noreturn]] (); +// CHECK-MESSAGES: :[[@LINE-1]]:5: warning: use a trailing return type for this function [modernize-use-trailing-return] +// CHECK-FIXES: {{^}}auto g2 {{[[][[]}}noreturn{{[]][]]}} () -> int;{{$}} + +// +// Samples which do not trigger the check +// + +auto ff(); +auto f() -> int; +auto f(int) -> int; +auto f(int arg) -> int; +auto f(int arg1, int arg2, int arg3) -> int; +auto f(int arg1, int arg2, int arg3, ...) -> int; +template <typename T> auto f(T t) -> int; + +void c(); +void c(int arg); +void c(int arg) { return; } + +struct D2 : B { + D2(); + virtual ~D2(); + + virtual auto f1(int, bool b) -> double final; + virtual auto base2(int, bool b) -> double override; + virtual auto base3() const -> float override final { } + + operator double(); +}; + +auto l1 = [](int arg) {}; +auto l2 = [](int arg) -> double {}; Index: docs/clang-tidy/checks/modernize-use-trailing-return.rst =================================================================== --- /dev/null +++ docs/clang-tidy/checks/modernize-use-trailing-return.rst @@ -0,0 +1,26 @@ +.. title:: clang-tidy - modernize-use-trailing-return + +modernize-use-trailing-return +============================= + +Rewrites function signatures to use a trailing return type +(introduced in C++11). This transformation is purely stylistic. +The return type before the function name is replaced by ``auto`` +and inserted after the function parameter list (and qualifiers). + +Example +------- + +.. code-block:: c++ + + int f1(); + inline int f2(int arg) noexcept; + virtual float f3() const && = delete; + +transforms to: + +.. code-block:: c++ + + auto f1() -> int; + inline auto f2(int arg) -> int noexcept; + virtual auto f3() const && -> float = delete; Index: docs/clang-tidy/checks/list.rst =================================================================== --- docs/clang-tidy/checks/list.rst +++ docs/clang-tidy/checks/list.rst @@ -210,6 +210,7 @@ modernize-use-noexcept modernize-use-nullptr modernize-use-override + modernize-use-trailing-return modernize-use-transparent-functors modernize-use-uncaught-exceptions modernize-use-using Index: docs/ReleaseNotes.rst =================================================================== --- docs/ReleaseNotes.rst +++ docs/ReleaseNotes.rst @@ -180,6 +180,11 @@ Detects usage of the deprecated member types of ``std::ios_base`` and replaces those that have a non-deprecated equivalent. +- New :doc:`modernize-use-trailing-return + <clang-tidy/checks/modernize-use-trailing-return>` check. + + Rewrites function signatures to use a trailing return type. + - New :doc:`readability-isolate-decl <clang-tidy/checks/readability-isolate-declaration>` check. Index: clang-tidy/modernize/UseTrailingReturnCheck.h =================================================================== --- /dev/null +++ clang-tidy/modernize/UseTrailingReturnCheck.h @@ -0,0 +1,35 @@ +//===--- UseTrailingReturnCheck.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_USETRAILINGRETURNCHECK_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_USETRAILINGRETURNCHECK_H + +#include "../ClangTidy.h" + +namespace clang { +namespace tidy { +namespace modernize { + +/// Rewrites function signatures to use a trailing return type. +/// +/// For the user-facing documentation see: +/// http://clang.llvm.org/extra/clang-tidy/checks/modernize-use-trailing-return.html +class UseTrailingReturnCheck : public ClangTidyCheck { +public: + UseTrailingReturnCheck(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_USETRAILINGRETURNCHECK_H Index: clang-tidy/modernize/UseTrailingReturnCheck.cpp =================================================================== --- /dev/null +++ clang-tidy/modernize/UseTrailingReturnCheck.cpp @@ -0,0 +1,207 @@ +//===--- UseTrailingReturnCheck.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 "UseTrailingReturnCheck.h" +#include "clang/AST/ASTContext.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" + +using namespace clang::ast_matchers; + +namespace clang { +namespace tidy { +namespace modernize { + +// very similar to UseOverrideCheck +static SourceLocation findTrailingReturnTypeSourceLocation( + const CharSourceRange &Range, const ASTContext &Ctx, + const SourceManager &SM, const LangOptions &LangOpts) { + const std::pair<FileID, unsigned> Loc = SM.getDecomposedLoc(Range.getBegin()); + const StringRef File = SM.getBufferData(Loc.first); + const char *TokenBegin = File.data() + Loc.second; + Lexer Lexer(SM.getLocForStartOfFile(Loc.first), LangOpts, File.begin(), + TokenBegin, File.end()); + Token T; + int NestedParens = 0; + SourceLocation Result; + while (!Lexer.LexFromRawLexer(T)) { + if (SM.isBeforeInTranslationUnit(Range.getEnd(), T.getLocation())) + break; + if (Result.isValid()) { + // we found the closing parenthesis, skip additional const and ref + // qualifiers + + if (T.is(tok::amp) || T.is(tok::ampamp)) { + Result = T.getEndLoc(); + continue; + } + + if (T.is(tok::raw_identifier)) { + IdentifierInfo &Info = Ctx.Idents.get( + StringRef(SM.getCharacterData(T.getLocation()), T.getLength())); + T.setIdentifierInfo(&Info); + T.setKind(Info.getTokenID()); + } + + if (T.is(tok::kw_const)) { + Result = T.getEndLoc(); + continue; + } + + return Result; + } + if (T.is(tok::l_paren)) + ++NestedParens; + else if (T.is(tok::r_paren)) { + --NestedParens; + if (NestedParens == 0) + Result = T.getEndLoc(); // store location, next token might be const + } + } + + if (Result.isValid()) + return Result; + + llvm_unreachable("Expected to find a closing parenthesis"); +} + +static SourceRange findReturnTypeAndCVSourceRange(const FunctionDecl &F, + const ASTContext &Ctx, + const SourceManager &SM, + const LangOptions &LangOpts) { + + // we start with the range of the return type and expand to neighboring const + // and volatile + SourceRange ReturnTypeRange = F.getReturnTypeSourceRange(); + + // create tokens for everything before the name of the function + const std::pair<FileID, unsigned> Loc = SM.getDecomposedLoc(F.getBeginLoc()); + const StringRef File = SM.getBufferData(Loc.first); + const char *TokenBegin = File.data() + Loc.second; + Lexer Lexer(SM.getLocForStartOfFile(Loc.first), LangOpts, File.begin(), + TokenBegin, File.end()); + Token T; + SmallVector<Token, 8> Tokens; + while (!Lexer.LexFromRawLexer(T)) { + if (SM.isBeforeInTranslationUnit(F.getLocation(), T.getLocation())) + break; + if (T.is(tok::raw_identifier)) { + IdentifierInfo &Info = Ctx.Idents.get( + StringRef(SM.getCharacterData(T.getLocation()), T.getLength())); + T.setIdentifierInfo(&Info); + T.setKind(Info.getTokenID()); + } + Tokens.push_back(T); + } + + // include const and volatile to the left and right of the return type + auto IsCV = [](Token T) { + return T.is(tok::kw_const) || T.is(tok::kw_volatile); + }; + + bool ExtendedLeft = false; + for (int i = 0; i < Tokens.size(); i++) { + // if we found the beginning of the return type, include const and volatile + // to the left + if (!SM.isBeforeInTranslationUnit(Tokens[i].getLocation(), + ReturnTypeRange.getBegin()) && + !ExtendedLeft) { + for (int j = i - 1; j >= 0 && IsCV(Tokens[j]); j--) + ReturnTypeRange.setBegin(Tokens[j].getLocation()); + ExtendedLeft = true; + } + // if we found the end of the return type, include const and volatile to the + // right + if (SM.isBeforeInTranslationUnit(ReturnTypeRange.getEnd(), + Tokens[i].getLocation())) { + for (int j = i; j < Tokens.size() && IsCV(Tokens[j]); j++) + ReturnTypeRange.setEnd(Tokens[j].getLocation()); + break; + } + } + + return ReturnTypeRange; +} + +void UseTrailingReturnCheck::registerMatchers(MatchFinder *Finder) { + if (!getLangOpts().CPlusPlus11) + return; + + Finder->addMatcher( + functionDecl(unless(anyOf(hasTrailingReturn(), returns(voidType()), + returns(autoType()), cxxConversionDecl()))) + .bind("f"), + this); +} + +void UseTrailingReturnCheck::check(const MatchFinder::MatchResult &Result) { + const auto *F = Result.Nodes.getNodeAs<FunctionDecl>("f"); + if (!F) + return; + + if (const auto *M = dyn_cast<CXXMethodDecl>(F)) + if (M->isImplicit() || M->getLocation().isMacroID()) + return; + + if (F->getDeclaredReturnType()->isFunctionPointerType()) { + diag( + F->getLocation(), + "use a trailing return type for this function (FixIt not implemented)"); + return; + } + + const auto &Ctx = *Result.Context; + const auto &SM = *Result.SourceManager; + const auto &LangOpts = getLangOpts(); + + SourceRange ReturnTypeCVRange = findReturnTypeAndCVSourceRange(*F, Ctx, SM, LangOpts); + if (!ReturnTypeCVRange.isValid()) { + diag(F->getLocation(), + "use a trailing return type for this function (failed to determine " + "return type source range, could clang resolve all #includes?)", + DiagnosticIDs::Level::Error); + return; + } + + const CharSourceRange CharRange = Lexer::makeFileCharRange( + CharSourceRange::getTokenRange(F->getSourceRange()), SM, LangOpts); + if (!CharRange.isValid()) + return; + const SourceLocation InsertionLoc = + findTrailingReturnTypeSourceLocation(CharRange, Ctx, SM, LangOpts); + + // extract return type as string + const std::string ReturnType = [&] { + // using the declared return type via + // F->getDeclaredReturnType().getAsString() discards user formatting and + // order (order of const, volatile, type, whitespace, space before & ...) + + const std::pair<FileID, unsigned> Beg = + SM.getDecomposedLoc(ReturnTypeCVRange.getBegin()); + const StringRef File = SM.getBufferData(Beg.first); + const char *BegPtr = File.data() + Beg.second; + + const std::pair<FileID, unsigned> End = + SM.getDecomposedLoc(Lexer::getLocForEndOfToken( + ReturnTypeCVRange.getEnd(), 0, SM, LangOpts)); + assert(Beg.first == End.first); + assert(Beg.second != End.second); + const char *EndPtr = File.data() + End.second; + + return std::string(BegPtr, EndPtr); + }(); + + auto D = + diag(F->getLocation(), "use a trailing return type for this function"); + D << FixItHint::CreateReplacement(ReturnTypeCVRange, "auto"); + D << FixItHint::CreateInsertion(InsertionLoc, " -> " + ReturnType); +} + +} // namespace modernize +} // namespace tidy +} // namespace clang Index: clang-tidy/modernize/ModernizeTidyModule.cpp =================================================================== --- clang-tidy/modernize/ModernizeTidyModule.cpp +++ clang-tidy/modernize/ModernizeTidyModule.cpp @@ -35,6 +35,7 @@ #include "UseNoexceptCheck.h" #include "UseNullptrCheck.h" #include "UseOverrideCheck.h" +#include "UseTrailingReturnCheck.h" #include "UseTransparentFunctorsCheck.h" #include "UseUncaughtExceptionsCheck.h" #include "UseUsingCheck.h" @@ -85,6 +86,8 @@ CheckFactories.registerCheck<UseNoexceptCheck>("modernize-use-noexcept"); CheckFactories.registerCheck<UseNullptrCheck>("modernize-use-nullptr"); CheckFactories.registerCheck<UseOverrideCheck>("modernize-use-override"); + CheckFactories.registerCheck<UseTrailingReturnCheck>( + "modernize-use-trailing-return"); CheckFactories.registerCheck<UseTransparentFunctorsCheck>( "modernize-use-transparent-functors"); CheckFactories.registerCheck<UseUncaughtExceptionsCheck>( Index: clang-tidy/modernize/CMakeLists.txt =================================================================== --- clang-tidy/modernize/CMakeLists.txt +++ clang-tidy/modernize/CMakeLists.txt @@ -29,6 +29,7 @@ UseNoexceptCheck.cpp UseNullptrCheck.cpp UseOverrideCheck.cpp + UseTrailingReturnCheck.cpp UseTransparentFunctorsCheck.cpp UseUncaughtExceptionsCheck.cpp UseUsingCheck.cpp
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