b35bb38f18
Change-Id: I26734c13515394162d88351a1cbe2b20abdac865
156 lines
4.7 KiB
C++
156 lines
4.7 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
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/*
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* This file is part of the LibreOffice project.
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/.
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*/
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#include <set>
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#include <stack>
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#include "check.hxx"
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#include "plugin.hxx"
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// Find non-const vars of 'char const *' type initialized with a const expr,
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// that could likely be const (and will then probably trigger further
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// loplugin:stringconstant findings).
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namespace {
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// It looks like Clang wrongly implements DR 4
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// (<http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#4>) and treats
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// a variable declared in an 'extern "..." {...}'-style linkage-specification as
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// if it contained the 'extern' specifier:
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bool hasExternalLinkage(VarDecl const * decl) {
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if (decl->getLinkageAndVisibility().getLinkage() != ExternalLinkage) {
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return false;
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}
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for (auto ctx = decl->getLexicalDeclContext();
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ctx->getDeclKind() != Decl::TranslationUnit;
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ctx = ctx->getLexicalParent())
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{
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if (auto ls = dyn_cast<LinkageSpecDecl>(ctx)) {
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if (!ls->hasBraces()) {
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return true;
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}
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if (auto prev = decl->getPreviousDecl()) {
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return hasExternalLinkage(prev);
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}
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return !decl->isInAnonymousNamespace();
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}
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}
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return true;
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}
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class ConstStringVar:
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public RecursiveASTVisitor<ConstStringVar>, public loplugin::Plugin
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{
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public:
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explicit ConstStringVar(loplugin::InstantiationData const & data):
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Plugin(data) {}
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void run() override {
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if (compiler.getLangOpts().CPlusPlus) {
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// clang::Expr::isCXX11ConstantExpr only works for C++
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TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
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for (auto v: vars_) {
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report(
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DiagnosticsEngine::Warning,
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"variable is only used as rvalue, should be const",
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v->getLocation())
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<< v->getSourceRange();
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}
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}
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}
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bool TraverseImplicitCastExpr(ImplicitCastExpr * expr) {
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bool match;
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switch (expr->getCastKind()) {
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case CK_NoOp:
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// OString CharPtrDetector ctor:
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match = bool(
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loplugin::TypeCheck(expr->getType()).Const().Pointer().Const()
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.Char());
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break;
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case CK_LValueToRValue:
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match = true;
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break;
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default:
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match = false;
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break;
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}
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bool pushed = false;
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if (match) {
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if (auto dr = dyn_cast<DeclRefExpr>(
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expr->getSubExpr()->IgnoreParenImpCasts()))
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{
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if (auto vd = dyn_cast<VarDecl>(dr->getDecl())) {
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if (vars_.find(vd->getCanonicalDecl()) != vars_.end()) {
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casted_.push(dr);
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pushed = true;
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}
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}
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}
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}
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bool b = RecursiveASTVisitor::TraverseImplicitCastExpr(expr);
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if (pushed) {
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casted_.pop();
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}
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return b;
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}
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bool VisitVarDecl(VarDecl const * decl) {
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if (ignoreLocation(decl)) {
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return true;
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}
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if (decl != decl->getCanonicalDecl()) {
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return true;
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}
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if (isa<ParmVarDecl>(decl) || hasExternalLinkage(decl)) {
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return true;
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}
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if (!loplugin::TypeCheck(decl->getType()).NonConstVolatile().Pointer()
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.Const().Char())
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{
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return true;
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}
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auto init = decl->getAnyInitializer();
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if (init == nullptr) {
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return true;
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}
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if (init->isInstantiationDependent()) {
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// avoid problems with isCXX11ConstantExpr in template code
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return true;
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}
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APValue v;
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if (!init->isCXX11ConstantExpr(compiler.getASTContext(), &v)) {
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return true;
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}
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vars_.insert(decl);
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return true;
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}
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bool VisitDeclRefExpr(DeclRefExpr const * expr) {
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if (!casted_.empty() && expr == casted_.top()) {
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return true;
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}
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auto vd = dyn_cast<VarDecl>(expr->getDecl());
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if (vd == nullptr) {
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return true;
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}
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vars_.erase(vd->getCanonicalDecl());
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return true;
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}
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private:
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std::set<VarDecl const *> vars_;
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std::stack<DeclRefExpr const *> casted_;
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};
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loplugin::Plugin::Registration<ConstStringVar> X("conststringvar");
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}
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/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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