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Diffstat (limited to 'compilerplugins/clang/unreffun.cxx')
| -rw-r--r-- | compilerplugins/clang/unreffun.cxx | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/compilerplugins/clang/unreffun.cxx b/compilerplugins/clang/unreffun.cxx new file mode 100644 index 000000000..353eee5f0 --- /dev/null +++ b/compilerplugins/clang/unreffun.cxx @@ -0,0 +1,198 @@ +/* -*- 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/. + */ + +#ifndef LO_CLANG_SHARED_PLUGINS + +#include <cassert> +#include <stack> +#include <string> + +#include "clang/AST/Attr.h" +#include "clang/Sema/SemaInternal.h" // warn_unused_function + +#include "plugin.hxx" + +namespace { + +bool isFriendDecl(Decl const * decl) { + return decl->getFriendObjectKind() != Decl::FOK_None; +} + +Decl const * getPreviousNonFriendDecl(Decl const * decl) { + for (;;) { + decl = decl->getPreviousDecl(); + if (decl == nullptr || !isFriendDecl(decl)) { + return decl; + } + } +} + +bool isSpecialMemberFunction(FunctionDecl const * decl) { + if (auto const ctor = dyn_cast<CXXConstructorDecl>(decl)) { + return ctor->isDefaultConstructor() || ctor->isCopyOrMoveConstructor(); + } + if (isa<CXXDestructorDecl>(decl)) { + return true; + } + if (auto const meth = dyn_cast<CXXMethodDecl>(decl)) { + return meth->isCopyAssignmentOperator() || meth->isMoveAssignmentOperator(); + } + return false; +} + +class UnrefFun: public loplugin::FilteringPlugin<UnrefFun> { +public: + explicit UnrefFun(loplugin::InstantiationData const & data): FilteringPlugin(data) {} + + void run() override + { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); } + + bool PreTraverseFriendDecl(FriendDecl * decl) { + friendFunction.push( dyn_cast_or_null<FunctionDecl>(decl->getFriendDecl())); + return true; + } + bool PostTraverseFriendDecl(FriendDecl *, bool ) { + friendFunction.pop(); + return true; + } + bool TraverseFriendDecl(FriendDecl * decl) { + PreTraverseFriendDecl(decl); + auto const ret = RecursiveASTVisitor::TraverseFriendDecl(decl); + PostTraverseFriendDecl(decl, ret); + return ret; + } + + bool VisitFunctionDecl(FunctionDecl const * decl); + +private: + std::stack<FunctionDecl const *> friendFunction; +}; + +bool UnrefFun::VisitFunctionDecl(FunctionDecl const * decl) { + if (ignoreLocation(decl)) { + return true; + } + + //TODO, filtering out any functions relating to (class) templates for now: + CXXRecordDecl const * r = dyn_cast<CXXRecordDecl>(decl->getDeclContext()); + if (r != nullptr + && (r->getTemplateSpecializationKind() != TSK_Undeclared + || r->isDependentContext())) + { + return true; + } + if (!friendFunction.empty() && decl == friendFunction.top()) { + if (auto const lex = dyn_cast<CXXRecordDecl>(decl->getLexicalDeclContext())) { + if (lex->isDependentContext()) { + return true; + } + } + } + + if (!(decl->isThisDeclarationADefinition() || isFriendDecl(decl) + || decl->isFunctionTemplateSpecialization())) + { + Decl const * prev = getPreviousNonFriendDecl(decl); + if (prev != nullptr/* && prev != decl->getPrimaryTemplate()*/) { + // Workaround for redeclarations that introduce visibility attributes + // (as is done with + // + // SAL_DLLPUBLIC_EXPORT GType lok_doc_view_get_type(); + // + // in libreofficekit/source/gtk/lokdocview.cxx): + if (decl->getAttr<VisibilityAttr>() != nullptr + && prev->getAttr<VisibilityAttr>() == nullptr) + { + return true; + } + report( + DiagnosticsEngine::Warning, + "redundant function%0 redeclaration", decl->getLocation()) + << ((decl->getTemplatedKind() + == FunctionDecl::TK_FunctionTemplate) + ? " template" : "") + << decl->getSourceRange(); + report( + DiagnosticsEngine::Note, "previous declaration is here", + prev->getLocation()) + << prev->getSourceRange(); + return true; + } + } + + FunctionDecl const * canon = decl->getCanonicalDecl(); + //TODO: is that the first? + if (canon->isDeleted() || canon->isReferenced() + || !(canon->isDefined() + ? decl->isThisDeclarationADefinition() : decl->isFirstDecl()) + || !compiler.getSourceManager().isInMainFile(canon->getLocation()) + || isInUnoIncludeFile(canon) + || canon->isMain() || canon->isMSVCRTEntryPoint() + || (decl->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate + && (decl->getDescribedFunctionTemplate()->spec_begin() + != decl->getDescribedFunctionTemplate()->spec_end())) + || (compiler.getDiagnostics().getDiagnosticLevel( + diag::warn_unused_function, decl->getLocation()) + < DiagnosticsEngine::Warning)) + { + return true; + } + if (canon->isExplicitlyDefaulted() && isSpecialMemberFunction(canon)) { + // If a special member function is explicitly defaulted on the first declaration, assume + // that its presence is always due to some interface design consideration, not to explicitly + // request a definition that might be worth to flag as unused (and C++20 may extend + // defaultability beyond special member functions to comparison operators, therefore + // explicitly check here for special member functions only): + return true; + } + LinkageInfo info(canon->getLinkageAndVisibility()); + if (info.getLinkage() == ExternalLinkage + && loplugin::hasCLanguageLinkageType(canon) && canon->isDefined() + && ((decl == canon && info.getVisibility() == DefaultVisibility) + || ((canon->hasAttr<ConstructorAttr>() + || canon->hasAttr<DestructorAttr>()) + && info.getVisibility() == HiddenVisibility))) + { + return true; + } + auto loc = decl->getLocation(); + if (compiler.getSourceManager().isMacroBodyExpansion(loc) + && (Lexer::getImmediateMacroName( + loc, compiler.getSourceManager(), compiler.getLangOpts()) + == "MDDS_MTV_DEFINE_ELEMENT_CALLBACKS")) + { + return true; + } + report( + DiagnosticsEngine::Warning, + (canon->isDefined() + ? (canon->isExternallyVisible() + ? "Unreferenced externally visible function%0 definition" + : "Unreferenced externally invisible function%0 definition") + : "Unreferenced function%0 declaration"), + decl->getLocation()) + << (decl->getTemplatedKind() == FunctionDecl::TK_FunctionTemplate + ? " template" : "") + << decl->getSourceRange(); + if (canon->isDefined() && !decl->isFirstDecl()) { + report( + DiagnosticsEngine::Note, "first declaration is here", + canon->getLocation()) + << canon->getSourceRange(); + } + return true; +} + +loplugin::Plugin::Registration<UnrefFun> unreffun("unreffun"); + +} + +#endif // LO_CLANG_SHARED_PLUGINS + +/* vim:set shiftwidth=4 softtabstop=4 expandtab: */ |