Index: clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt =================================================================== --- clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt +++ clang-tools-extra/trunk/clang-tidy/misc/CMakeLists.txt @@ -6,6 +6,7 @@ MiscTidyModule.cpp RedundantSmartptrGet.cpp SwappedArgumentsCheck.cpp + UnusedRAII.cpp UseOverride.cpp LINK_LIBS Index: clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp =================================================================== --- clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp +++ clang-tools-extra/trunk/clang-tidy/misc/MiscTidyModule.cpp @@ -14,6 +14,7 @@ #include "BoolPointerImplicitConversion.h" #include "RedundantSmartptrGet.h" #include "SwappedArgumentsCheck.h" +#include "UnusedRAII.h" #include "UseOverride.h" namespace clang { @@ -35,6 +36,9 @@ "misc-swapped-arguments", new ClangTidyCheckFactory()); CheckFactories.addCheckFactory( + "misc-unused-raii", + new ClangTidyCheckFactory()); + CheckFactories.addCheckFactory( "misc-use-override", new ClangTidyCheckFactory()); } Index: clang-tools-extra/trunk/clang-tidy/misc/UnusedRAII.h =================================================================== --- clang-tools-extra/trunk/clang-tidy/misc/UnusedRAII.h +++ clang-tools-extra/trunk/clang-tidy/misc/UnusedRAII.h @@ -0,0 +1,47 @@ +//===--- UnusedRAII.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_RAII_H +#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_RAII_H + +#include "../ClangTidy.h" + +namespace clang { +namespace tidy { + +/// \brief Finds temporaries that look like RAII objects. +/// +/// The canonical example for this is a scoped lock. +/// \code +/// { +/// scoped_lock(&global_mutex); +/// critical_section(); +/// } +/// \endcode +/// The destructor of the scoped_lock is called before the critical_section is +/// entered, leaving it unprotected. +/// +/// We apply a number of heuristics to reduce the false positive count of this +/// check: +/// - Ignore code expanded from macros. Testing frameworks make heavy use of +/// this. +/// - Ignore types with no user-declared constructor. Those are very unlikely +/// to be RAII objects. +/// - Ignore objects at the end of a compound statement (doesn't change behavior). +/// - Ignore objects returned from a call. +class UnusedRAIICheck : public ClangTidyCheck { +public: + void registerMatchers(ast_matchers::MatchFinder *Finder) override; + void check(const ast_matchers::MatchFinder::MatchResult &Result) override; +}; + +} // namespace tidy +} // namespace clang + +#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MISC_UNUSED_RAII_H Index: clang-tools-extra/trunk/clang-tidy/misc/UnusedRAII.cpp =================================================================== --- clang-tools-extra/trunk/clang-tidy/misc/UnusedRAII.cpp +++ clang-tools-extra/trunk/clang-tidy/misc/UnusedRAII.cpp @@ -0,0 +1,83 @@ +//===--- UnusedRAII.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 "UnusedRAII.h" +#include "clang/AST/ASTContext.h" +#include "clang/Lex/Lexer.h" + +using namespace clang::ast_matchers; + +namespace clang { +namespace ast_matchers { +AST_MATCHER(CXXRecordDecl, hasUserDeclaredDestructor) { + // TODO: If the dtor is there but empty we don't want to warn either. + return Node.hasUserDeclaredDestructor(); +} +} // namespace ast_matchers + +namespace tidy { + +void UnusedRAIICheck::registerMatchers(MatchFinder *Finder) { + // Look for temporaries that are constructed in-place and immediately + // destroyed. Look for temporaries created by a functional cast but not for + // those returned from a call. + auto BindTemp = bindTemporaryExpr(unless(has(callExpr()))).bind("temp"); + Finder->addMatcher( + exprWithCleanups( + unless(hasAncestor(decl( + anyOf(recordDecl(ast_matchers::isTemplateInstantiation()), + functionDecl(ast_matchers::isTemplateInstantiation()))))), + hasParent(compoundStmt().bind("compound")), + hasDescendant(typeLoc().bind("typeloc")), + hasType(recordDecl(hasUserDeclaredDestructor())), + anyOf(has(BindTemp), has(functionalCastExpr(has(BindTemp))))) + .bind("expr"), + this); +} + +void UnusedRAIICheck::check(const MatchFinder::MatchResult &Result) { + const auto *E = Result.Nodes.getStmtAs("expr"); + + // We ignore code expanded from macros to reduce the number of false + // positives. + if (E->getLocStart().isMacroID()) + return; + + // Don't emit a warning for the last statement in the surrounding compund + // statement. + const auto *CS = Result.Nodes.getStmtAs("compound"); + if (E == CS->body_back()) + return; + + // Emit a warning. + auto D = diag(E->getLocStart(), "object destroyed immediately after " + "creation; did you mean to name the object?"); + const char *Replacement = " give_me_a_name"; + + // If this is a default ctor we have to remove the parens or we'll introduce a + // most vexing parse. + const auto *BTE = Result.Nodes.getStmtAs("temp"); + if (const auto *TOE = dyn_cast(BTE->getSubExpr())) + if (TOE->getNumArgs() == 0) { + D << FixItHint::CreateReplacement( + CharSourceRange::getTokenRange(TOE->getParenOrBraceRange()), + Replacement); + return; + } + + // Otherwise just suggest adding a name. + const auto *TL = Result.Nodes.getNodeAs("typeloc"); + D << FixItHint::CreateInsertion( + Lexer::getLocForEndOfToken(TL->getLocEnd(), 0, *Result.SourceManager, + Result.Context->getLangOpts()), + Replacement); +} + +} // namespace tidy +} // namespace clang Index: clang-tools-extra/trunk/test/clang-tidy/misc-unused-raii.cpp =================================================================== --- clang-tools-extra/trunk/test/clang-tidy/misc-unused-raii.cpp +++ clang-tools-extra/trunk/test/clang-tidy/misc-unused-raii.cpp @@ -0,0 +1,61 @@ +// RUN: $(dirname %s)/check_clang_tidy_fix.sh %s misc-unused-raii %t +// REQUIRES: shell + +struct Foo { + Foo(); + Foo(int); + Foo(int, int); + ~Foo(); +}; + +struct Bar { + Bar(); + Foo f; +}; + +template +void qux() { + T(42); +} + +template +struct TFoo { + TFoo(T); + ~TFoo(); +}; + +Foo f(); + +struct Ctor { + Ctor(int); + Ctor() { + Ctor(0); // TODO: warn here. + } +}; + +void test() { + Foo(42); +// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: object destroyed immediately after creation; did you mean to name the object? +// CHECK-FIXES: Foo give_me_a_name(42); + Foo(23, 42); +// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: object destroyed immediately after creation; did you mean to name the object? +// CHECK-FIXES: Foo give_me_a_name(23, 42); + Foo(); +// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: object destroyed immediately after creation; did you mean to name the object? +// CHECK-FIXES: Foo give_me_a_name; + TFoo(23); +// CHECK-MESSAGES: :[[@LINE-1]]:3: warning: object destroyed immediately after creation; did you mean to name the object? +// CHECK-FIXES: TFoo give_me_a_name(23); + + Bar(); + f(); + qux(); + +#define M Foo(); + M + + { + Foo(); + } + Foo(); +}