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/* -*- 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/.
*/
#include <cassert>
#include <string>
#include "plugin.hxx"
#include "compat.hxx"
//
// We don't like using C-style casts in C++ code
//
namespace {
bool hasCLanguageLinkageType(FunctionDecl const * decl) {
return decl->isExternC() || compat::isInExternCContext(*decl);
}
QualType resolvePointers(QualType type) {
while (type->isPointerType()) {
type = type->getAs<PointerType>()->getPointeeType();
}
return type;
}
class CStyleCast:
public RecursiveASTVisitor<CStyleCast>, public loplugin::Plugin
{
public:
explicit CStyleCast(InstantiationData const & data):
Plugin(data), externCFunction(false)
{}
virtual void run() override {
if (compiler.getLangOpts().CPlusPlus) {
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
}
bool TraverseFunctionDecl(FunctionDecl * decl);
bool VisitCStyleCastExpr(const CStyleCastExpr * expr);
bool VisitImplicitCastExpr(ImplicitCastExpr const * expr);
private:
bool externCFunction;
};
static const char * recommendedFix(clang::CastKind ck) {
switch(ck) {
case CK_IntegralToPointer: return "reinterpret_cast";
case CK_PointerToIntegral: return "reinterpret_cast";
case CK_BaseToDerived: return "static_cast";
default: return "???";
}
}
bool CStyleCast::TraverseFunctionDecl(FunctionDecl * decl) {
bool ext = hasCLanguageLinkageType(decl)
&& decl->isThisDeclarationADefinition();
if (ext) {
assert(!externCFunction);
externCFunction = true;
}
bool ret = RecursiveASTVisitor::TraverseFunctionDecl(decl);
if (ext) {
externCFunction = false;
}
return ret;
}
bool CStyleCast::VisitCStyleCastExpr(const CStyleCastExpr * expr) {
if (ignoreLocation(expr)) {
return true;
}
// casting to void is typically used when a parameter or field is only used in
// debug mode, and we want to eliminate an "unused" warning
if( expr->getCastKind() == CK_ToVoid ) {
return true;
}
// ignore integral-type conversions for now, there is unsufficient agreement about
// the merits of C++ style casting in this case
if( expr->getCastKind() == CK_IntegralCast ) {
return true;
}
if( expr->getCastKind() == CK_NoOp ) {
return true;
}
std::string incompFrom;
std::string incompTo;
if( expr->getCastKind() == CK_BitCast ) {
QualType t = resolvePointers(expr->getSubExprAsWritten()->getType());
// Ignore "safe" casts for now that involve casting from void* (and can
// thus not be interpreted as either a static_cast or a
// reinterpret_cast, with potentially different results):
if (t->isVoidType()) {
return true;
}
if (t->isIncompleteType()) {
incompFrom = "incomplete ";
}
if (resolvePointers(expr->getType())->isIncompleteType()) {
incompTo = "incomplete ";
}
}
// ignore stuff from inside templates for now
if( expr->getCastKind() == CK_Dependent ) {
return true;
}
if (externCFunction || expr->getLocStart().isMacroID()) {
SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(
expr->getLocStart());
StringRef filename = compiler.getSourceManager().getFilename(spellingLocation);
// ignore C code
if ( filename.endswith(".h") ) {
return true;
}
}
report(
DiagnosticsEngine::Warning,
"c-style cast, type=%0, from=%1%2, to=%3%4, recommendedFix=%5",
expr->getSourceRange().getBegin())
<< expr->getCastKind()
<< incompFrom << expr->getSubExprAsWritten()->getType()
<< incompTo << expr->getType()
<< recommendedFix(expr->getCastKind())
<< expr->getSourceRange();
return true;
}
bool CStyleCast::VisitImplicitCastExpr(const ImplicitCastExpr * expr) {
if (ignoreLocation(expr) || expr->getCastKind() != CK_BitCast) {
return true;
}
QualType t = expr->getType();
if (!(t->isPointerType()
&& t->getAs<PointerType>()->getPointeeType()->isVoidType()
&& expr->getSubExpr()->getType()->isPointerType()))
{
return true;
}
Expr const * e = expr->getSubExpr()->IgnoreParenImpCasts();
while (isa<CXXConstCastExpr>(e)) {
e = dyn_cast<CXXConstCastExpr>(e)->getSubExpr()->IgnoreParenImpCasts();
}
if (isa<CXXReinterpretCastExpr>(e)) {
report(
DiagnosticsEngine::Warning,
("redundant reinterpret_cast, result is implicitly cast to void"
" pointer"),
e->getExprLoc())
<< e->getSourceRange();
}
return true;
}
loplugin::Plugin::Registration< CStyleCast > X("cstylecast");
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
|
