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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 <limits>
#include <string>
#include "plugin.hxx"
//
// We don't like using C-style casts in C++ code
//
namespace {
bool areSimilar(QualType type1, QualType type2) {
auto t1 = type1.getCanonicalType().getTypePtr();
auto t2 = type2.getCanonicalType().getTypePtr();
for (;;) {
if (t1->isPointerType()) {
if (!t2->isPointerType()) {
return false;
}
auto t1a = t1->getAs<PointerType>();
auto t2a = t2->getAs<PointerType>();
t1 = t1a->getPointeeType().getTypePtr();
t2 = t2a->getPointeeType().getTypePtr();
} else if (t1->isMemberPointerType()) {
if (!t2->isMemberPointerType()) {
return false;
}
auto t1a = t1->getAs<MemberPointerType>();
auto t2a = t2->getAs<MemberPointerType>();
if (t1a->getClass()->getCanonicalTypeInternal()
!= t2a->getClass()->getCanonicalTypeInternal())
{
return false;
}
t1 = t1a->getPointeeType().getTypePtr();
t2 = t2a->getPointeeType().getTypePtr();
} else if (t1->isConstantArrayType()) {
if (!t2->isConstantArrayType()) {
return false;
}
auto t1a = static_cast<ConstantArrayType const *>(
t1->getAsArrayTypeUnsafe());
auto t2a = static_cast<ConstantArrayType const *>(
t2->getAsArrayTypeUnsafe());
if (t1a->getSize() != t2a->getSize()) {
return false;
}
t1 = t1a->getElementType().getTypePtr();
t2 = t2a->getElementType().getTypePtr();
} else if (t1->isIncompleteArrayType()) {
if (!t2->isIncompleteArrayType()) {
return false;
}
auto t1a = static_cast<IncompleteArrayType const *>(
t1->getAsArrayTypeUnsafe());
auto t2a = static_cast<IncompleteArrayType const *>(
t2->getAsArrayTypeUnsafe());
t1 = t1a->getElementType().getTypePtr();
t2 = t2a->getElementType().getTypePtr();
} else {
return false;
}
if (t1 == t2) {
return true;
}
}
}
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) {}
virtual void run() override {
if (compiler.getLangOpts().CPlusPlus) {
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
}
bool TraverseLinkageSpecDecl(LinkageSpecDecl * decl);
bool VisitCStyleCastExpr(const CStyleCastExpr * expr);
private:
bool isConstCast(QualType from, QualType to);
bool isFromCIncludeFile(SourceLocation spellingLocation) const;
bool isSharedCAndCppCode(SourceLocation location) const;
unsigned int externCContexts_ = 0;
};
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 nullptr;
}
}
bool CStyleCast::TraverseLinkageSpecDecl(LinkageSpecDecl * decl) {
assert(externCContexts_ != std::numeric_limits<unsigned int>::max()); //TODO
++externCContexts_;
bool ret = RecursiveASTVisitor::TraverseLinkageSpecDecl(decl);
assert(externCContexts_ != 0);
--externCContexts_;
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 insufficient agreement about
// the merits of C++ style casting in this case
if( expr->getCastKind() == CK_IntegralCast ) {
return true;
}
char const * perf = nullptr;
if( expr->getCastKind() == CK_NoOp ) {
QualType t1 = expr->getSubExpr()->getType();
QualType t2 = expr->getType();
if (t1->isPointerType() && t2->isPointerType()) {
t1 = t1->getAs<PointerType>()->getPointeeType();
t2 = t2->getAs<PointerType>()->getPointeeType();
} else if (t1->isLValueReferenceType() && t2->isLValueReferenceType()) {
t1 = t1->getAs<LValueReferenceType>()->getPointeeType();
t2 = t2->getAs<LValueReferenceType>()->getPointeeType();
} else {
return true;
}
if (isConstCast(
expr->getSubExprAsWritten()->getType(),
expr->getTypeAsWritten()))
{
perf = "const_cast";
}
}
if (isSharedCAndCppCode(expr->getLocStart())) {
return true;
}
std::string incompFrom;
std::string incompTo;
if( expr->getCastKind() == CK_BitCast ) {
if (resolvePointers(expr->getSubExprAsWritten()->getType())
->isIncompleteType())
{
incompFrom = "incomplete ";
}
if (resolvePointers(expr->getType())->isIncompleteType()) {
incompTo = "incomplete ";
}
}
if (perf == nullptr) {
perf = recommendedFix(expr->getCastKind());
}
std::string performs;
if (perf != nullptr) {
performs = std::string(" (performs: ") + perf + ")";
}
report(
DiagnosticsEngine::Warning, "C-style cast from %0%1 to %2%3%4 (%5)",
expr->getSourceRange().getBegin())
<< incompFrom << expr->getSubExprAsWritten()->getType()
<< incompTo << expr->getType() << performs
<< expr->getCastKindName()
<< expr->getSourceRange();
return true;
}
bool CStyleCast::isConstCast(QualType from, QualType to) {
if (to->isReferenceType()
&& to->getAs<ReferenceType>()->getPointeeType()->isObjectType())
{
if (!from->isObjectType()) {
return false;
}
from = compiler.getASTContext().getPointerType(from);
to = compiler.getASTContext().getPointerType(
to->getAs<ReferenceType>()->getPointeeType());
} else {
if (from->isArrayType()) {
from = compiler.getASTContext().getPointerType(
from->getAsArrayTypeUnsafe()->getElementType());
} else if (from->isFunctionType()) {
compiler.getASTContext().getPointerType(from);
}
}
return areSimilar(from, to);
}
bool CStyleCast::isFromCIncludeFile(SourceLocation spellingLocation) const {
return !compiler.getSourceManager().isInMainFile(spellingLocation)
&& (StringRef(
compiler.getSourceManager().getPresumedLoc(spellingLocation)
.getFilename())
.endswith(".h"));
}
bool CStyleCast::isSharedCAndCppCode(SourceLocation location) const {
while (compiler.getSourceManager().isMacroArgExpansion(location)) {
location = compiler.getSourceManager().getImmediateMacroCallerLoc(
location);
}
// Assume that code is intended to be shared between C and C++ if it comes
// from an include file ending in .h, and is either in an extern "C" context
// or the body of a macro definition:
return
isFromCIncludeFile(compiler.getSourceManager().getSpellingLoc(location))
&& (externCContexts_ != 0
|| compiler.getSourceManager().isMacroBodyExpansion(location));
}
loplugin::Plugin::Registration< CStyleCast > X("cstylecast");
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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