From 727fd1aeed41e14b6b1335d233976b0176058760 Mon Sep 17 00:00:00 2001 From: Daniel Jasper Date: Tue, 19 Apr 2016 13:48:39 +0000 Subject: [PATCH] Initial version of misc-unused-using-decl check. llvm-svn: 266735 --- .../clang-tidy/misc/CMakeLists.txt | 3 +- .../clang-tidy/misc/MiscTidyModule.cpp | 3 + .../clang-tidy/misc/UnusedAliasDeclsCheck.h | 1 + .../clang-tidy/misc/UnusedUsingDeclsCheck.cpp | 73 +++++++++++++++++++ .../clang-tidy/misc/UnusedUsingDeclsCheck.h | 41 +++++++++++ .../docs/clang-tidy/checks/list.rst | 1 + .../checks/misc-unused-using-decls.rst | 14 ++++ .../clang-tidy/misc-unused-using-decls.cpp | 27 +++++++ 8 files changed, 162 insertions(+), 1 deletion(-) create mode 100644 clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp create mode 100644 clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.h create mode 100644 clang-tools-extra/docs/clang-tidy/checks/misc-unused-using-decls.rst create mode 100644 clang-tools-extra/test/clang-tidy/misc-unused-using-decls.cpp diff --git a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt index e3ab929e677a..916073b38c61 100644 --- a/clang-tools-extra/clang-tidy/misc/CMakeLists.txt +++ b/clang-tools-extra/clang-tidy/misc/CMakeLists.txt @@ -32,10 +32,11 @@ add_clang_library(clangTidyMiscModule SwappedArgumentsCheck.cpp ThrowByValueCatchByReferenceCheck.cpp UndelegatedConstructor.cpp + UniqueptrResetReleaseCheck.cpp UnusedAliasDeclsCheck.cpp UnusedParametersCheck.cpp UnusedRAIICheck.cpp - UniqueptrResetReleaseCheck.cpp + UnusedUsingDeclsCheck.cpp VirtualNearMissCheck.cpp LINK_LIBS diff --git a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp index f4393c273515..1d667b501614 100644 --- a/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp +++ b/clang-tools-extra/clang-tidy/misc/MiscTidyModule.cpp @@ -44,6 +44,7 @@ #include "UnusedAliasDeclsCheck.h" #include "UnusedParametersCheck.h" #include "UnusedRAIICheck.h" +#include "UnusedUsingDeclsCheck.h" #include "VirtualNearMissCheck.h" namespace clang { @@ -118,6 +119,8 @@ public: CheckFactories.registerCheck( "misc-unused-parameters"); CheckFactories.registerCheck("misc-unused-raii"); + CheckFactories.registerCheck( + "misc-unused-using-decls"); CheckFactories.registerCheck( "misc-virtual-near-miss"); } diff --git a/clang-tools-extra/clang-tidy/misc/UnusedAliasDeclsCheck.h b/clang-tools-extra/clang-tidy/misc/UnusedAliasDeclsCheck.h index 346fb691ed19..6606b73e69eb 100644 --- a/clang-tools-extra/clang-tidy/misc/UnusedAliasDeclsCheck.h +++ b/clang-tools-extra/clang-tidy/misc/UnusedAliasDeclsCheck.h @@ -11,6 +11,7 @@ #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_ALIAS_DECLS_H #include "../ClangTidy.h" +#include "llvm/ADT/DenseMap.h" namespace clang { namespace tidy { diff --git a/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp b/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp new file mode 100644 index 000000000000..5d93357e3985 --- /dev/null +++ b/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.cpp @@ -0,0 +1,73 @@ +//===--- UnusedUsingDeclsCheck.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 "UnusedUsingDeclsCheck.h" +#include "clang/AST/ASTContext.h" +#include "clang/ASTMatchers/ASTMatchFinder.h" +#include "clang/Lex/Lexer.h" + +using namespace clang::ast_matchers; + +namespace clang { +namespace tidy { +namespace misc { + +void UnusedUsingDeclsCheck::registerMatchers(MatchFinder *Finder) { + Finder->addMatcher(usingDecl(isExpansionInMainFile()).bind("using"), this); + Finder->addMatcher(recordType(hasDeclaration(namedDecl().bind("used"))), + this); +} + +void UnusedUsingDeclsCheck::check(const MatchFinder::MatchResult &Result) { + if (const auto *Using = Result.Nodes.getNodeAs("using")) { + // FIXME: Implement the correct behavior for using declarations with more + // than one shadow. + if (Using->shadow_size() != 1) + return; + const auto* TargetDecl = Using->shadow_begin()->getTargetDecl(); + + // FIXME: Handle other target types. + if (!isa(TargetDecl)) + return; + + FoundDecls[TargetDecl] = Using; + FoundRanges[TargetDecl] = CharSourceRange::getCharRange( + Using->getLocStart(), + Lexer::findLocationAfterToken( + Using->getLocEnd(), tok::semi, *Result.SourceManager, + Result.Context->getLangOpts(), + /*SkipTrailingWhitespaceAndNewLine=*/true)); + return; + } + + // Mark using declarations as used by setting FoundDecls' value to zero. As + // the AST is walked in order, usages are only marked after a the + // corresponding using declaration has been found. + // FIXME: This currently doesn't look at whether the type reference is + // actually found with the help of the using declaration. + if (const auto *Used = Result.Nodes.getNodeAs("used")) { + if (FoundDecls.find(Used) != FoundDecls.end()) + FoundDecls[Used] = nullptr; + } +} + +void UnusedUsingDeclsCheck::onEndOfTranslationUnit() { + for (const auto &FoundDecl : FoundDecls) { + if (FoundDecl.second == nullptr) + continue; + diag(FoundDecl.second->getLocation(), "using decl %0 is unused") + << FoundDecl.second + << FixItHint::CreateRemoval(FoundRanges[FoundDecl.first]); + } + FoundDecls.clear(); +} + +} // namespace misc +} // namespace tidy +} // namespace clang diff --git a/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.h b/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.h new file mode 100644 index 000000000000..9c899e8f1787 --- /dev/null +++ b/clang-tools-extra/clang-tidy/misc/UnusedUsingDeclsCheck.h @@ -0,0 +1,41 @@ +//===--- UnusedUsingDeclsCheck.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_MISC_UNUSED_USING_DECLS_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_USING_DECLS_H + +#include "../ClangTidy.h" +#include "llvm/ADT/DenseMap.h" + +namespace clang { +namespace tidy { +namespace misc { + +/// Finds unused using declarations. +/// +/// For the user-facing documentation see: +/// http://clang.llvm.org/extra/clang-tidy/checks/misc-unused-using-decls.html +class UnusedUsingDeclsCheck : public ClangTidyCheck { +public: + UnusedUsingDeclsCheck(StringRef Name, ClangTidyContext *Context) + : ClangTidyCheck(Name, Context) {} + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; + void onEndOfTranslationUnit() override; + +private: + llvm::DenseMap FoundDecls; + llvm::DenseMap FoundRanges; +}; + +} // namespace misc +} // namespace tidy +} // namespace clang + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_USING_DECLS_H diff --git a/clang-tools-extra/docs/clang-tidy/checks/list.rst b/clang-tools-extra/docs/clang-tidy/checks/list.rst index 14ea9e96e7b7..b677e6e3276b 100644 --- a/clang-tools-extra/docs/clang-tidy/checks/list.rst +++ b/clang-tools-extra/docs/clang-tidy/checks/list.rst @@ -80,6 +80,7 @@ Clang-Tidy Checks misc-unused-alias-decls misc-unused-parameters misc-unused-raii + misc-unused-using-decls misc-virtual-near-miss modernize-deprecated-headers modernize-loop-convert diff --git a/clang-tools-extra/docs/clang-tidy/checks/misc-unused-using-decls.rst b/clang-tools-extra/docs/clang-tidy/checks/misc-unused-using-decls.rst new file mode 100644 index 000000000000..8296dc380c38 --- /dev/null +++ b/clang-tools-extra/docs/clang-tidy/checks/misc-unused-using-decls.rst @@ -0,0 +1,14 @@ +.. title:: clang-tidy - misc-unused-using-decls + +misc-unused-using-decls +======================= + +Finds unused ``using`` declarations. + +Example: + +.. code:: c++ + + namespace n { class C; } + using n::C; // Never actually used. + diff --git a/clang-tools-extra/test/clang-tidy/misc-unused-using-decls.cpp b/clang-tools-extra/test/clang-tidy/misc-unused-using-decls.cpp new file mode 100644 index 000000000000..110c1b46fbbf --- /dev/null +++ b/clang-tools-extra/test/clang-tidy/misc-unused-using-decls.cpp @@ -0,0 +1,27 @@ +// RUN: %check_clang_tidy %s misc-unused-using-decls %t + +// ----- Definitions ----- +template class vector {}; +namespace n { +class A; +class B; +class C; +class D { public: static int i; }; +} + +// ----- Using declarations ----- +// eol-comments aren't removed (yet) +using n::A; // A +// CHECK-MESSAGES: :[[@LINE-1]]:10: warning: using decl 'A' is unused +// CHECK-FIXES: {{^}}// A +using n::B; +using n::C; +using n::D; + +// ----- Usages ----- +void f(B b); +void g() { + vector data; + D::i = 1; +} +