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Diffstat (limited to 'compilerplugins/clang/external.cxx')
| -rw-r--r-- | compilerplugins/clang/external.cxx | 323 |
1 files changed, 323 insertions, 0 deletions
diff --git a/compilerplugins/clang/external.cxx b/compilerplugins/clang/external.cxx new file mode 100644 index 000000000000..bb4bcbf36d08 --- /dev/null +++ b/compilerplugins/clang/external.cxx @@ -0,0 +1,323 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */ +/* + * 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 <algorithm> +#include <cassert> + +#include "clang/Sema/SemaDiagnostic.h" + +#include "check.hxx" +#include "plugin.hxx" + +namespace +{ +// It appears that, given a function declaration, there is no way to determine +// the language linkage of the function's type, only of the function's name +// (via FunctionDecl::isExternC); however, in a case like +// +// extern "C" { static void f(); } +// +// the function's name does not have C language linkage while the function's +// type does (as clarified in C++11 [decl.link]); cf. <http://clang-developers. +// 42468.n3.nabble.com/Language-linkage-of-function-type-tt4037248.html> +// "Language linkage of function type": +bool hasCLanguageLinkageType(FunctionDecl const* decl) +{ + assert(decl != nullptr); + if (decl->isExternC()) + { + return true; + } + if (decl->isInExternCContext()) + { + return true; + } + return false; +} + +bool derivesFromTestFixture(CXXRecordDecl const* decl) +{ + static auto const pred = [](CXXBaseSpecifier const& spec) { + if (auto const t = spec.getType()->getAs<RecordType>()) + { // (may be a template parameter) + return derivesFromTestFixture(dyn_cast<CXXRecordDecl>(t->getDecl())); + } + return false; + }; + return loplugin::DeclCheck(decl).Class("TestFixture").Namespace("CppUnit").GlobalNamespace() + || std::any_of(decl->bases_begin(), decl->bases_end(), pred) + || std::any_of(decl->vbases_begin(), decl->vbases_end(), pred); +} + +class External : public loplugin::FilteringPlugin<External> +{ +public: + explicit External(loplugin::InstantiationData const& data) + : FilteringPlugin(data) + { + } + + void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); } + + bool VisitTagDecl(TagDecl const* decl) + { + /*TODO:*/ + return true; // in general, moving classes or enumerations into an unnamed namespace can break ADL + if (isa<ClassTemplateSpecializationDecl>(decl)) + { + return true; + } + if (!decl->isThisDeclarationADefinition()) + { + return true; + } + if (isa<CXXRecordDecl>(decl->getDeclContext())) + { + return true; + } + if (!compiler.getLangOpts().CPlusPlus) + { + return true; + } + if (auto const d = dyn_cast<CXXRecordDecl>(decl)) + { + if (d->getDescribedClassTemplate() != nullptr) + { + return true; + } + if (auto const attr = d->getAttr<VisibilityAttr>()) + { + if (attr->getVisibility() == VisibilityAttr::Default) + { + // If the class definition has explicit default visibility, then assume that it + // needs to be present (e.g., a backwards-compatibility stub like in + // cppuhelper/source/compat.cxx): + return true; + } + } + if (derivesFromTestFixture(d)) + { + // The names of CppUnit tests (that can be specified with CPPUNIT_TEST_NAME) are + // tied to the fully-qualified names of classes derived from CppUnit::TestFixture, + // so avoid unnamed namespaces in those classes' names: + return true; + } + } + return handleDeclaration(decl); + } + + bool VisitFunctionDecl(FunctionDecl const* decl) + { + if (isa<CXXMethodDecl>(decl)) + { + return true; + } + if (decl->getTemplatedKind() != FunctionDecl::TK_NonTemplate) + { + return true; + } + if (!decl->isThisDeclarationADefinition()) + { + return true; + } + if (decl->isMain()) + { + return true; + } + if (auto const attr = decl->getAttr<VisibilityAttr>()) + { + if (attr->getVisibility() == VisibilityAttr::Default) + { + // If the function definition has explicit default visibility, then assume that it + // needs to be present (e.g., only called via dlopen, or a backwards-compatibility + // stub like in sal/osl/all/compat.cxx): + return true; + } + } + auto const canon = decl->getCanonicalDecl(); + if (hasCLanguageLinkageType(canon) + && (canon->hasAttr<ConstructorAttr>() || canon->hasAttr<DestructorAttr>())) + { + return true; + } + if (compiler.getDiagnostics().getDiagnosticLevel(diag::warn_unused_function, + decl->getLocation()) + < DiagnosticsEngine::Warning) + { + // Don't warn about e.g. + // + // G_DEFINE_TYPE (GLOAction, g_lo_action, G_TYPE_OBJECT); + // + // in vcl/unx/gtk/gloactiongroup.cxx (which expands to non-static g_lo_action_get_type + // function definition), which is already wrapped in + // + // #pragma GCC diagnostic ignored "-Wunused-function" + return true; + } + return handleDeclaration(decl); + } + + bool VisitVarDecl(VarDecl const* decl) + { + if (decl->isStaticDataMember()) + { + return true; + } + if (isa<VarTemplateSpecializationDecl>(decl)) + { + return true; + } + if (!decl->isThisDeclarationADefinition()) + { + return true; + } + return handleDeclaration(decl); + } + + bool VisitClassTemplateDecl(ClassTemplateDecl const* decl) + { + /*TODO:*/ + return true; // in general, moving classes or enumerations into an unnamed namespace can break ADL + if (!decl->isThisDeclarationADefinition()) + { + return true; + } + if (isa<CXXRecordDecl>(decl->getDeclContext())) + { + return true; + } + return handleDeclaration(decl); + } + + bool VisitFunctionTemplateDecl(FunctionTemplateDecl const* decl) + { + if (!decl->isThisDeclarationADefinition()) + { + return true; + } + if (isa<CXXRecordDecl>(decl->getDeclContext())) + { + return true; + } + return handleDeclaration(decl); + } + + bool VisitVarTemplateDecl(VarTemplateDecl const* decl) + { + if (!decl->isThisDeclarationADefinition()) + { + return true; + } + return handleDeclaration(decl); + } + +private: + template <typename T> void reportSpecializations(T specializations) + { + for (auto const d : specializations) + { + auto const k = d->getTemplateSpecializationKind(); + if (isTemplateExplicitInstantiationOrSpecialization(k)) + { + report(DiagnosticsEngine::Note, + "explicit %select{instantiation|specialization}0 is here", d->getLocation()) + << (k == TSK_ExplicitSpecialization) << d->getSourceRange(); + } + } + } + + bool handleDeclaration(NamedDecl const* decl) + { + if (ignoreLocation(decl)) + { + return true; + } + if (decl->getLinkageInternal() < +#if CLANG_VERSION >= 40000 + ModuleLinkage +#else + ExternalLinkage +#endif + ) + { + return true; + } + //TODO: in some cases getLinkageInternal() appears to report ExternalLinkage instead of + // UniqueExternalLinkage: + if (decl->isInAnonymousNamespace()) + { + return true; + } + for (Decl const* d = decl; d != nullptr; d = d->getPreviousDecl()) + { + if (!compiler.getSourceManager().isInMainFile(d->getLocation())) + { + return true; + } + } + if (compiler.getSourceManager().isMacroBodyExpansion(decl->getLocation()) + && (Lexer::getImmediateMacroName(decl->getLocation(), compiler.getSourceManager(), + compiler.getLangOpts()) + == "MDDS_MTV_DEFINE_ELEMENT_CALLBACKS")) + { + // Even wrapping in an unnamed namespace or sneaking "static" into the macro wouldn't + // help, as then some of the functions it defines would be flagged as unused: + return true; + } + TypedefNameDecl const* typedefed = nullptr; + if (auto const d = dyn_cast<TagDecl>(decl)) + { + typedefed = d->getTypedefNameForAnonDecl(); + } + bool canStatic; + if (auto const d = dyn_cast<CXXRecordDecl>(decl)) + { + canStatic = d->isUnion() && d->isAnonymousStructOrUnion(); + } + else + { + canStatic = isa<FunctionDecl>(decl) || isa<VarDecl>(decl) + || isa<FunctionTemplateDecl>(decl) || isa<VarTemplateDecl>(decl); + } + auto const canUnnamed = compiler.getLangOpts().CPlusPlus + && !(isa<FunctionDecl>(decl) || isa<FunctionTemplateDecl>(decl)); + // in general, moving functions into an unnamed namespace can break ADL + assert(canStatic || canUnnamed); + report( + DiagnosticsEngine::Warning, + ("externally available%select{| typedef'ed}0 entity %1 is not previously declared in an" + " included file (if it is only used in this translation unit," + " %select{|make it static}2%select{| or }3%select{|put it in an unnamed namespace}4;" + " otherwise, provide a declaration of it in an included file)"), + decl->getLocation()) + << (typedefed != nullptr) << (typedefed == nullptr ? decl : typedefed) << canStatic + << (canStatic && canUnnamed) << canUnnamed << decl->getSourceRange(); + for (auto d = decl->getPreviousDecl(); d != nullptr; d = d->getPreviousDecl()) + { + report(DiagnosticsEngine::Note, "previous declaration is here", d->getLocation()) + << d->getSourceRange(); + } + //TODO: Class template specializations can be in the enclosing namespace, so no need to + // list them here (as they won't need to be put into the unnamed namespace too, unlike for + // specializations of function and variable templates); and explicit function template + // specializations cannot have storage-class specifiers, so as we only suggest to make + // function templates static (but not to move them into an unnamed namespace), no need to + // list function template specializations here, either: + if (auto const d = dyn_cast<VarTemplateDecl>(decl)) + { + reportSpecializations(d->specializations()); + } + return true; + } +}; + +loplugin::Plugin::Registration<External> X("external"); +} + +/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */ |