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/* -*- 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 <set>
#include <stack>
#include "check.hxx"
#include "plugin.hxx"
// Find non-const vars of 'char const *' type initialized with a const expr,
// that could likely be const (and will then probably trigger further
// loplugin:stringconstant findings).
namespace {
// It looks like Clang wrongly implements DR 4
// (<http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#4>) and treats
// a variable declared in an 'extern "..." {...}'-style linkage-specification as
// if it contained the 'extern' specifier:
bool hasExternalLinkage(VarDecl const * decl) {
if (decl->getLinkageAndVisibility().getLinkage() != ExternalLinkage) {
return false;
}
for (auto ctx = decl->getLexicalDeclContext();
ctx->getDeclKind() != Decl::TranslationUnit;
ctx = ctx->getLexicalParent())
{
if (auto ls = dyn_cast<LinkageSpecDecl>(ctx)) {
if (!ls->hasBraces()) {
return true;
}
if (auto prev = decl->getPreviousDecl()) {
return hasExternalLinkage(prev);
}
return !decl->isInAnonymousNamespace();
}
}
return true;
}
class ConstStringVar:
public RecursiveASTVisitor<ConstStringVar>, public loplugin::Plugin
{
public:
explicit ConstStringVar(loplugin::InstantiationData const & data):
Plugin(data) {}
void run() override {
if (compiler.getLangOpts().CPlusPlus) {
// clang::Expr::isCXX11ConstantExpr only works for C++
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
for (auto v: vars_) {
report(
DiagnosticsEngine::Warning,
"variable is only used as rvalue, should be const",
v->getLocation())
<< v->getSourceRange();
}
}
}
bool TraverseImplicitCastExpr(ImplicitCastExpr * expr) {
bool match;
switch (expr->getCastKind()) {
case CK_NoOp:
// OString CharPtrDetector ctor:
match = bool(
loplugin::TypeCheck(expr->getType()).Const().Pointer().Const()
.Char());
break;
case CK_LValueToRValue:
match = true;
break;
default:
match = false;
break;
}
bool pushed = false;
if (match) {
if (auto dr = dyn_cast<DeclRefExpr>(
expr->getSubExpr()->IgnoreParenImpCasts()))
{
if (auto vd = dyn_cast<VarDecl>(dr->getDecl())) {
if (vars_.find(vd->getCanonicalDecl()) != vars_.end()) {
casted_.push(dr);
pushed = true;
}
}
}
}
bool b = RecursiveASTVisitor::TraverseImplicitCastExpr(expr);
if (pushed) {
casted_.pop();
}
return b;
}
bool VisitVarDecl(VarDecl const * decl) {
if (ignoreLocation(decl)) {
return true;
}
if (decl != decl->getCanonicalDecl()) {
return true;
}
if (isa<ParmVarDecl>(decl) || hasExternalLinkage(decl)) {
return true;
}
if (!loplugin::TypeCheck(decl->getType()).NonConstVolatile().Pointer()
.Const().Char())
{
return true;
}
auto init = decl->getAnyInitializer();
if (init == nullptr) {
return true;
}
if (init->isInstantiationDependent()) {
// avoid problems with isCXX11ConstantExpr in template code
return true;
}
APValue v;
if (!init->isCXX11ConstantExpr(compiler.getASTContext(), &v)) {
return true;
}
vars_.insert(decl);
return true;
}
bool VisitDeclRefExpr(DeclRefExpr const * expr) {
if (!casted_.empty() && expr == casted_.top()) {
return true;
}
auto vd = dyn_cast<VarDecl>(expr->getDecl());
if (vd == nullptr) {
return true;
}
vars_.erase(vd->getCanonicalDecl());
return true;
}
private:
std::set<VarDecl const *> vars_;
std::stack<DeclRefExpr const *> casted_;
};
loplugin::Plugin::Registration<ConstStringVar> X("conststringvar");
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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