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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 "check.hxx"
#include "compat.hxx"
#include "plugin.hxx"
// Find variable declarations at namespace scope that need not have external
// linkage.
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 ExternVar: public RecursiveASTVisitor<ExternVar>, public loplugin::Plugin
{
public:
explicit ExternVar(loplugin::InstantiationData const & data): Plugin(data)
{}
void run() override
{ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
bool VisitVarDecl(VarDecl const * decl) {
if (ignoreLocation(decl)) {
return true;
}
if (decl->isStaticDataMember()) {
return true;
}
if (!(decl->isFirstDecl()
&& compiler.getSourceManager().isInMainFile(decl->getLocation())
&& hasExternalLinkage(decl)))
{
return true;
}
auto def = decl->getDefinition();
if (def == nullptr) {
// Code like
//
// namespace { extern int v; }
// int f() { return sizeof(v); }
//
// is already handled by Clang itself with an error "variable 'v' is
// not needed and will not be emitted"
return true;
}
if (loplugin::DeclCheck(def).Var("_pRawDllMain").GlobalNamespace()) {
return true;
}
SourceLocation argLoc;
if (compat::isMacroArgExpansion(compiler, def->getLocation(), &argLoc)
&& (Lexer::getImmediateMacroName(
argLoc, compiler.getSourceManager(), compiler.getLangOpts())
== "DEFINE_GUID"))
{
return true;
}
report(
DiagnosticsEngine::Warning,
"variable with external linkage not declared in an include file",
def->getLocation())
<< def->getSourceRange();
report(
DiagnosticsEngine::Note,
("should either have internal linkage or be declared in an include"
" file"),
def->getLocation())
<< def->getSourceRange();
for (auto prev = def;;) {
prev = prev->getPreviousDecl();
if (prev == nullptr) {
break;
}
report(
DiagnosticsEngine::Note, "previously declared here",
prev->getLocation())
<< prev->getSourceRange();
}
return true;
}
};
loplugin::Plugin::Registration<ExternVar> X("externvar");
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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