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Diffstat (limited to 'compilerplugins/clang/unnecessarylocking.cxx')
| -rw-r--r-- | compilerplugins/clang/unnecessarylocking.cxx | 215 |
1 files changed, 215 insertions, 0 deletions
diff --git a/compilerplugins/clang/unnecessarylocking.cxx b/compilerplugins/clang/unnecessarylocking.cxx new file mode 100644 index 000000000..c00758b81 --- /dev/null +++ b/compilerplugins/clang/unnecessarylocking.cxx @@ -0,0 +1,215 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* + * This file is part of the LibreOffice project. + * + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. + */ + +#include <cassert> +#include <string> +#include <iostream> +#include <fstream> +#include <set> +#include <unordered_set> + +#include <clang/AST/CXXInheritance.h> + +#include "config_clang.h" + +#include "plugin.hxx" +#include "check.hxx" + +/** +Look for methods that are taking a lock at the top of the method, but then not +touching any object-local state. In which case the method might not need locking. + +TODO + +(*) check if the data being returned is never modified, in which case locking is not necessary + +*/ + +namespace +{ +class UnnecessaryLocking : public loplugin::FilteringPlugin<UnnecessaryLocking> +{ +public: + explicit UnnecessaryLocking(loplugin::InstantiationData const& data) + : FilteringPlugin(data) + { + } + + virtual bool preRun() override + { + // StringRef fn(handler.getMainFileName()); + // if (loplugin::isSamePathname(fn, WORKDIR "/YaccTarget/unoidl/source/sourceprovider-parser.cxx")) + // return false; + return true; + } + virtual void run() override + { + if (preRun()) + TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); + } + + bool TraverseCXXMethodDecl(CXXMethodDecl*); + bool VisitCXXThisExpr(const CXXThisExpr*); + +private: + bool isSolarMutexLockGuardStmt(const Stmt*); + const Stmt* isOtherMutexLockGuardStmt(const Stmt*); + std::vector<bool> m_TouchesThis; + // so we ignore the CxxThisEpxr that references the maMutex in the guard expression + std::vector<const Stmt*> m_IgnoreThis; +}; + +bool UnnecessaryLocking::TraverseCXXMethodDecl(CXXMethodDecl* cxxMethodDecl) +{ + if (ignoreLocation(cxxMethodDecl)) + return true; + + if (!cxxMethodDecl->isInstance()) + return true; + if (!cxxMethodDecl->isThisDeclarationADefinition()) + return true; + + auto compoundStmt = dyn_cast_or_null<CompoundStmt>(cxxMethodDecl->getBody()); + if (!compoundStmt || compoundStmt->size() < 1) + return true; + + const Stmt* firstStmt = *compoundStmt->body_begin(); + bool solarMutex = isSolarMutexLockGuardStmt(firstStmt); + const Stmt* ignoreThisStmt = nullptr; + if (!solarMutex) + ignoreThisStmt = isOtherMutexLockGuardStmt(firstStmt); + if (!solarMutex && ignoreThisStmt == nullptr) + return true; + + m_TouchesThis.push_back(false); + m_IgnoreThis.push_back(ignoreThisStmt); + + bool rv = FilteringPlugin::TraverseCXXMethodDecl(cxxMethodDecl); + + if (!m_TouchesThis.back()) + { + StringRef fn = getFilenameOfLocation( + compiler.getSourceManager().getSpellingLoc(cxxMethodDecl->getBeginLoc())); + if ( + // template magic + !loplugin::isSamePathname(fn, SRCDIR "/include/comphelper/unique_disposing_ptr.hxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/inc/unobaseclass.hxx") + // toolkit needs to lock around access to static methods in vcl + && !loplugin::isSamePathname(fn, SRCDIR "/toolkit/source/awt/vclxtoolkit.cxx") + && !loplugin::isSamePathname(fn, + SRCDIR "/toolkit/source/controls/tree/treecontrolpeer.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/toolkit/source/awt/vclxcontainer.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/toolkit/source/awt/vclxdevice.cxx") + // touching shared global data + && !loplugin::isSamePathname(fn, SRCDIR + "/framework/source/fwi/classes/protocolhandlercache.cxx") + // lock around access to static methods in vcl + && !loplugin::isSamePathname(fn, SRCDIR "/framework/source/services/taskcreatorsrv.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/svx/source/dialog/SafeModeUI.cxx") + && !loplugin::isSamePathname(fn, SRCDIR + "/svx/source/accessibility/AccessibleFrameSelector.cxx") + // not sure + && !loplugin::isSamePathname(fn, SRCDIR "/sfx2/source/dialog/filedlghelper.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sfx2/source/appl/appdispatchprovider.cxx") + // touching shared global data + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/unocore/unoftn.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/unocore/unolinebreak.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/unocore/unoobj.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/unocore/unorefmk.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/unocore/unotbl.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/filter/xml/xmltexti.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/uibase/uno/dlelstnr.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/access/accdoc.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/access/acccontext.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/unocore/unocontentcontrol.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sw/source/core/unocore/unobkm.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sc/source/ui/unoobj/docuno.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sc/source/ui/unoobj/afmtuno.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/sc/source/ui/unoobj/appluno.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/unoxml/source/dom/documentbuilder.cxx") + && !loplugin::isSamePathname( + fn, SRCDIR "/sd/source/ui/accessibility/AccessibleDrawDocumentView.cxx") + && !loplugin::isSamePathname(fn, SRCDIR "/starmath/source/accessibility.cxx") + && !loplugin::isSamePathname(fn, + SRCDIR "/starmath/source/AccessibleSmElementsControl.cxx")) + { + report(DiagnosticsEngine::Warning, "unnecessary locking", cxxMethodDecl->getBeginLoc()) + << cxxMethodDecl->getSourceRange(); + } + } + + m_TouchesThis.pop_back(); + m_IgnoreThis.pop_back(); + + return rv; +} + +bool UnnecessaryLocking::isSolarMutexLockGuardStmt(const Stmt* stmt) +{ + auto declStmt = dyn_cast<DeclStmt>(stmt); + if (!declStmt) + return false; + if (!declStmt->isSingleDecl()) + return false; + auto varDecl = dyn_cast<VarDecl>(declStmt->getSingleDecl()); + if (!varDecl) + return false; + auto tc = loplugin::TypeCheck(varDecl->getType()); + if (!tc.Class("SolarMutexGuard").GlobalNamespace() + && !tc.Class("SolarMutexClearableGuard").GlobalNamespace() + && !tc.Class("SolarMutexResettableGuard").GlobalNamespace() + && !tc.Class("SolarMutexTryAndBuyGuard").GlobalNamespace()) + return false; + return true; +} + +const Stmt* UnnecessaryLocking::isOtherMutexLockGuardStmt(const Stmt* stmt) +{ + auto declStmt = dyn_cast<DeclStmt>(stmt); + if (!declStmt) + return nullptr; + if (!declStmt->isSingleDecl()) + return nullptr; + auto varDecl = dyn_cast<VarDecl>(declStmt->getSingleDecl()); + if (!varDecl) + return nullptr; + auto tc = loplugin::TypeCheck(varDecl->getType()); + if (!tc.Class("unique_lock").StdNamespace() && !tc.Class("scoped_lock").StdNamespace()) + return nullptr; + auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(varDecl->getInit()); + if (!cxxConstructExpr || cxxConstructExpr->getNumArgs() < 1) + return nullptr; + auto memberExpr = dyn_cast<MemberExpr>(cxxConstructExpr->getArg(0)); + if (!memberExpr) + return nullptr; + auto thisStmt = memberExpr->getBase(); + return thisStmt; +} + +bool UnnecessaryLocking::VisitCXXThisExpr(const CXXThisExpr* cxxThisExpr) +{ + if (ignoreLocation(cxxThisExpr)) + return true; + // just in case + if (m_TouchesThis.empty()) + return true; + // already found something + if (m_TouchesThis.back()) + return true; + if (m_IgnoreThis.back() && m_IgnoreThis.back() == cxxThisExpr) + return true; + m_TouchesThis.back() = true; + return true; +} + +/** off by default because each warning needs to be carefully inspected */ +loplugin::Plugin::Registration<UnnecessaryLocking> unnecessarylocking("unnecessarylocking", false); +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |