Neil Roberts
32e937ae2d
Instead of having a hard-coded list of smart pointer types, the plugin now checks if the called type has a method called “get” which returns a pointer with the same type as the overall expression. The intention is that this should be general enough to catch all smart pointers. Change-Id: I8c6f21f34a9debb81765155c544d0564c0f8ec58 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/211848 Reviewed-by: Neil Roberts <nroberts@libreoffice.org> Tested-by: Jenkins
137 lines
4.2 KiB
C++
137 lines
4.2 KiB
C++
/* -*- 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/.
|
|
*/
|
|
#ifndef LO_CLANG_SHARED_PLUGINS
|
|
|
|
#include <cassert>
|
|
#include <string>
|
|
#include <iostream>
|
|
#include <fstream>
|
|
#include <set>
|
|
|
|
#include <clang/AST/CXXInheritance.h>
|
|
|
|
#include "check.hxx"
|
|
#include "plugin.hxx"
|
|
|
|
/**
|
|
* Look for:
|
|
* &(*x)
|
|
* when x is a smart pointer like unique_ptr. That can be transformed to:
|
|
* x.get()
|
|
*
|
|
* This is important when x is null, because in that case *x is undefined behavior. This can lead to
|
|
* difficult bugs because the compiler will often let you get away with it, but some compilers might
|
|
* also take advantage of that to assume that x is never null and then optimise away chunks of code.
|
|
* See tdf#173585 for an example.
|
|
*
|
|
* Either way x.get() is easier to understand.
|
|
*
|
|
* Whether the object is a smart pointer or not is determined by whether it has a get() method which
|
|
* returns the same type as the original expression.
|
|
*/
|
|
|
|
namespace
|
|
{
|
|
class SmartPointerDerefAddress : public loplugin::FilteringPlugin<SmartPointerDerefAddress>
|
|
{
|
|
public:
|
|
explicit SmartPointerDerefAddress(loplugin::InstantiationData const& data)
|
|
: FilteringPlugin(data)
|
|
{
|
|
}
|
|
|
|
virtual void run() override
|
|
{
|
|
if (preRun())
|
|
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
|
|
}
|
|
|
|
bool VisitUnaryOperator(UnaryOperator const*);
|
|
};
|
|
|
|
bool cxxRecordHasGetMethod(const CXXRecordDecl* recordDecl, const QualType& expressionType)
|
|
{
|
|
for (auto method : recordDecl->methods())
|
|
{
|
|
if (!method->isInstance() || method->param_size() != 0
|
|
|| !loplugin::DeclCheck(method).Function("get"))
|
|
{
|
|
continue;
|
|
}
|
|
|
|
QualType returnType = method->getReturnType().getUnqualifiedType().getCanonicalType();
|
|
|
|
if (returnType == expressionType)
|
|
return true;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool cxxRecordOrBaseHasGetMethod(const CXXRecordDecl* recordDecl, const QualType& expressionType)
|
|
{
|
|
if (cxxRecordHasGetMethod(recordDecl, expressionType))
|
|
return true;
|
|
|
|
auto baseCallback = [&](const CXXRecordDecl* baseRecordDecl) {
|
|
return !cxxRecordHasGetMethod(baseRecordDecl, expressionType);
|
|
};
|
|
|
|
return !recordDecl->forallBases(baseCallback);
|
|
}
|
|
|
|
bool SmartPointerDerefAddress::VisitUnaryOperator(UnaryOperator const* unaryOperator)
|
|
{
|
|
if (ignoreLocation(unaryOperator))
|
|
return true;
|
|
if (unaryOperator->getBeginLoc().isMacroID())
|
|
return true;
|
|
if (unaryOperator->getOpcode() != UO_AddrOf)
|
|
return true;
|
|
auto subExpr = unaryOperator->getSubExpr()->IgnoreParenImpCasts();
|
|
auto innerOp = dyn_cast<CXXOperatorCallExpr>(subExpr);
|
|
if (!innerOp || innerOp->getOperator() != OO_Star)
|
|
return true;
|
|
|
|
const Expr* derefedExpr = innerOp->getArg(0);
|
|
|
|
// Remove any implicit casts so we can get the type of the original expression, not the one
|
|
// where operator* is defined
|
|
while (const ImplicitCastExpr* castExpr = dyn_cast<ImplicitCastExpr>(derefedExpr))
|
|
derefedExpr = castExpr->getSubExpr();
|
|
|
|
// Check if the dereferenced type is a struct or a class that also has a get method that returns
|
|
// the same type as the whole expression
|
|
const CXXRecordDecl* recordDecl = derefedExpr->getType()->getAsCXXRecordDecl();
|
|
|
|
if (!recordDecl)
|
|
return true;
|
|
|
|
QualType expressionType = unaryOperator->getType().getUnqualifiedType().getCanonicalType();
|
|
|
|
if (cxxRecordOrBaseHasGetMethod(recordDecl, expressionType))
|
|
{
|
|
report(DiagnosticsEngine::Warning,
|
|
"'*' followed by '&' operating on %0, rather use '.get()'",
|
|
unaryOperator->getBeginLoc())
|
|
<< innerOp->getArg(0)->getType() << unaryOperator->getSourceRange();
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
loplugin::Plugin::Registration<SmartPointerDerefAddress>
|
|
smartpointerderefaddress("smartpointerderefaddress");
|
|
|
|
} // namespace
|
|
|
|
#endif // LO_CLANG_SHARED_PLUGINS
|
|
|
|
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
|