office-gobmx/compilerplugins/clang/passstuffbyref.cxx
Noel Grandin c03efa7c6c loplugin-passbyref: ignore non-base declarations
Only consider base declarations, not overriden ones, or we warn on methods that
are overriding stuff from external libraries.

Change-Id: I08791c96f7adba5997ad237a98e7c08a759042ad
2014-05-22 07:54:54 +02:00

91 lines
3 KiB
C++

/* -*- 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 <string>
#include <set>
#include "plugin.hxx"
// Find places where various things are passed by value.
// It's not very efficient, because we generally end up copying it twice - once into the parameter and
// again into the destination.
// They should rather be passed by reference.
namespace {
class PassStuffByRef:
public RecursiveASTVisitor<PassStuffByRef>, public loplugin::Plugin
{
public:
explicit PassStuffByRef(InstantiationData const & data): Plugin(data) {}
virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
bool VisitFunctionDecl(const FunctionDecl * decl);
};
bool PassStuffByRef::VisitFunctionDecl(const FunctionDecl * functionDecl) {
if (ignoreLocation(functionDecl)) {
return true;
}
// only warn on the definition/prototype of the function,
// not on the function implementation
if (functionDecl->isThisDeclarationADefinition() && functionDecl->getPreviousDecl() != nullptr) {
return true;
}
// only consider base declarations, not overriden ones, or we warn on methods that
// are overriding stuff from external libraries
if (isa<CXXMethodDecl>(functionDecl)) {
CXXMethodDecl const * m = dyn_cast<CXXMethodDecl>(functionDecl);
if (m->size_overridden_methods() > 0)
return true;
}
unsigned n = functionDecl->getNumParams();
for (unsigned i = 0; i != n; ++i) {
const ParmVarDecl * pvDecl = functionDecl->getParamDecl(i);
QualType t1 { pvDecl->getType() };
if (!t1->isClassType()) {
continue;
}
string typeName = t1.getUnqualifiedType().getCanonicalType().getAsString();
bool bFound = false;
if (typeName == "class rtl::OUString" ||
typeName == "class rtl::OString" ||
typeName.find("class com::sun::star::uno::Sequence") == 0) {
bFound = true;
}
if (!bFound && !t1->isIncompleteType()) {
const clang::Type* type = t1.getTypePtrOrNull();
if (type != nullptr) {
clang::CharUnits size = compiler.getASTContext().getTypeSizeInChars(type);
if (size.getQuantity() > 64) {
bFound = true;
}
}
}
if (bFound) {
report(
DiagnosticsEngine::Warning,
"passing " + typeName + " by value, rather pass by reference .e.g. 'const " + typeName + "&'",
pvDecl->getSourceRange().getBegin())
<< pvDecl->getSourceRange();
}
}
return true;
}
loplugin::Plugin::Registration< PassStuffByRef > X("passstuffbyref");
}
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */