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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.
*
* Based on LLVM/Clang.
*
* This file is distributed under the University of Illinois Open Source
* License. See LICENSE.TXT for details.
*
*/
#include <cassert>
#include <string>
#include <iostream>
#include <fstream>
#include "config_clang.h"
#include "plugin.hxx"
#include "check.hxx"
#include <unordered_set>
#include <unordered_map>
/*
Look for local variables that can be std::move'd into parameters.
TODO
(*) Ideally we would use a proper data-flow analysis, to detect that the var is dead after this point,
like the one in clang at include/clang/Analysis/CFG.h
(*) we could expand the set of approved/interesting types
*/
namespace
{
class MoveIt : public loplugin::FilteringPlugin<MoveIt>
{
public:
explicit MoveIt(loplugin::InstantiationData const& data)
: FilteringPlugin(data)
{
}
virtual bool preRun() override
{
std::string fn(handler.getMainFileName());
loplugin::normalizeDotDotInFilePath(fn);
// false +, needs to check if the moved-from var is outside a loop
if (loplugin::hasPathnamePrefix(
fn, SRCDIR "/drawinglayer/source/primitive3d/sdrdecompositiontools3d.cxx"))
return false;
if (loplugin::hasPathnamePrefix(
fn, SRCDIR "/drawinglayer/source/processor2d/vclmetafileprocessor2d.cxx"))
return false;
if (loplugin::hasPathnamePrefix(fn, SRCDIR "/drawinglayer/source/tools/emfphelperdata.cxx"))
return false;
if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sc/source/core/tool/reftokenhelper.cxx"))
return false;
if (loplugin::hasPathnamePrefix(fn,
SRCDIR "/svx/source/svdraw/svdotextpathdecomposition.cxx"))
return false;
if (loplugin::hasPathnamePrefix(fn, SRCDIR "/svx/source/svdraw/svdcrtv.cxx"))
return false;
if (loplugin::hasPathnamePrefix(fn, SRCDIR "/svx/source/table/tablehandles.cxx"))
return false;
if (loplugin::hasPathnamePrefix(fn, SRCDIR "/svx/source/xoutdev/xpool.cxx"))
return false;
return true;
}
virtual void run() override
{
if (preRun())
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
for (auto const& pair : m_possibles)
{
auto const& possible = pair.second;
report(DiagnosticsEngine::Warning, "can std::move this var into this param",
possible.argExpr->getBeginLoc());
report(DiagnosticsEngine::Note, "passing to this param",
possible.calleeParmVarDecl->getBeginLoc());
report(DiagnosticsEngine::Note, "local var declared here",
possible.localVarDecl->getBeginLoc());
report(DiagnosticsEngine::Note, "type declared here",
possible.recordDecl->getBeginLoc());
}
}
bool VisitCXXMemberCallExpr(const CXXMemberCallExpr*);
bool VisitCXXConstructExpr(const CXXConstructExpr*);
bool VisitDeclRefExpr(const DeclRefExpr*);
private:
bool isInterestingType(QualType);
struct Possible
{
const Expr* argExpr;
const ParmVarDecl* calleeParmVarDecl;
const VarDecl* localVarDecl;
const CXXRecordDecl* recordDecl;
const DeclRefExpr* dre;
};
std::unordered_map<const VarDecl*, Possible> m_possibles;
std::unordered_set<const VarDecl*> m_rejected;
};
bool MoveIt::VisitCXXMemberCallExpr(const CXXMemberCallExpr* topExpr)
{
if (ignoreLocation(topExpr))
return true;
const CXXMethodDecl* methodDecl = topExpr->getMethodDecl();
if (!methodDecl)
return true;
unsigned len = std::min(topExpr->getNumArgs(), methodDecl->getNumParams());
for (unsigned i = 0; i < len; ++i)
{
// check if the parameter is a moveable type
const ParmVarDecl* parmVarDecl = methodDecl->getParamDecl(i);
if (!parmVarDecl->getType()->isRecordType())
continue;
const CXXRecordDecl* recordDecl
= dyn_cast<CXXRecordDecl>(parmVarDecl->getType()->getAsRecordDecl());
if (!recordDecl || !recordDecl->hasMoveConstructor() || recordDecl->isTriviallyCopyable())
continue;
if (!isInterestingType(parmVarDecl->getType()))
continue;
// check if (a) we're making a copy to pass to the param and (b) we're making a copy of a local var
const Expr* argExpr = topExpr->getArg(i);
if (!argExpr)
continue;
const CXXConstructExpr* argSubExpr = dyn_cast<CXXConstructExpr>(argExpr->IgnoreImplicit());
if (!argSubExpr || argSubExpr->getNumArgs() == 0)
continue;
const DeclRefExpr* dre = dyn_cast<DeclRefExpr>(argSubExpr->getArg(0)->IgnoreImplicit());
if (!dre)
continue;
const VarDecl* localVarDecl = dyn_cast<VarDecl>(dre->getDecl());
if (!localVarDecl || localVarDecl->getType()->isReferenceType()
|| localVarDecl->getType()->isPointerType() || !localVarDecl->hasLocalStorage())
continue;
// because sometimes the parameter type is some obscured STL thing
if (!isInterestingType(localVarDecl->getType()))
continue;
if (m_rejected.count(localVarDecl))
continue;
m_possibles[localVarDecl] = Possible{ argExpr, parmVarDecl, localVarDecl, recordDecl, dre };
}
return true;
}
bool MoveIt::VisitCXXConstructExpr(const CXXConstructExpr* topExpr)
{
if (ignoreLocation(topExpr))
return true;
if (isa<CXXTemporaryObjectExpr>(topExpr))
return true;
const CXXConstructorDecl* methodDecl = topExpr->getConstructor();
if (!methodDecl)
return true;
unsigned len = std::min(topExpr->getNumArgs(), methodDecl->getNumParams());
for (unsigned i = 0; i < len; ++i)
{
// check if the parameter is a moveable type
const ParmVarDecl* parmVarDecl = methodDecl->getParamDecl(i);
if (!parmVarDecl->getType()->isRecordType())
continue;
const CXXRecordDecl* recordDecl
= dyn_cast<CXXRecordDecl>(parmVarDecl->getType()->getAsRecordDecl());
if (!recordDecl || !recordDecl->hasMoveConstructor() || recordDecl->isTriviallyCopyable())
continue;
if (!isInterestingType(parmVarDecl->getType()))
continue;
// check if (a) we're making a copy to pass to the param and (b) we're making a copy of a local var
const Expr* argExpr = topExpr->getArg(i);
if (!argExpr)
continue;
const CXXConstructExpr* argSubExpr = dyn_cast<CXXConstructExpr>(argExpr->IgnoreImplicit());
if (!argSubExpr || argSubExpr->getNumArgs() == 0)
continue;
const DeclRefExpr* dre = dyn_cast<DeclRefExpr>(argSubExpr->getArg(0)->IgnoreImplicit());
if (!dre)
continue;
const VarDecl* localVarDecl = dyn_cast<VarDecl>(dre->getDecl());
if (!localVarDecl || localVarDecl->getType()->isReferenceType()
|| localVarDecl->getType()->isPointerType() || !localVarDecl->hasLocalStorage())
continue;
// because sometimes the parameter type is some obscured STL thing
if (!isInterestingType(localVarDecl->getType()))
continue;
if (m_rejected.count(localVarDecl))
continue;
m_possibles[localVarDecl] = Possible{ argExpr, parmVarDecl, localVarDecl, recordDecl, dre };
}
return true;
}
/// If we have pushed a possibility, and then we see that possibility again,
/// then we cannot std::move it, because it is being referenced after being moved.
///
bool MoveIt::VisitDeclRefExpr(const DeclRefExpr* declRefExpr)
{
if (ignoreLocation(declRefExpr))
return true;
const VarDecl* localVarDecl = dyn_cast<VarDecl>(declRefExpr->getDecl());
if (!localVarDecl)
return true;
auto it = m_possibles.find(localVarDecl);
if (it == m_possibles.end())
return true;
// ignoring the DeclRefExpr* for the expression where we found the Possible
if (it->second.dre == declRefExpr)
return true;
m_possibles.erase(it);
m_rejected.insert(localVarDecl);
return true;
}
/// Exclude boring types, so that we don't generate too many low-value conversions.
/// e.g. for now I ignore ref-counted types like Sequence and OUString and css::uno::Reference,
/// because that generates too many changes
bool MoveIt::isInterestingType(QualType qt)
{
if (qt->isEnumeralType())
return false;
if (!qt->isRecordType())
return false;
auto tc = loplugin::TypeCheck(qt);
// clang-format off
return !tc.ClassOrStruct("iterator")
&& !tc.ClassOrStruct("const_iterator")
&& !tc.Typedef("iterator")
&& !tc.Typedef("const_iterator")
&& !tc.Class("_Safe_iterator")
&& !tc.Typedef("string")
&& !tc.ClassOrStruct("shared_ptr").StdNamespace()
&& !tc.ClassOrStruct("shared_ptr").Namespace("boost")
&& !tc.Class("B2DHomMatrix").Namespace("basegfx").GlobalNamespace()
&& !tc.Class("Pipe").Namespace("osl")
&& !tc.Class("Any").Namespace("uno")
&& !tc.Class("TypeDescription").Namespace("uno")
&& !tc.Class("UnoInterfaceReference").Namespace("uno")
&& !tc.Class("ByteSequence").Namespace("rtl").GlobalNamespace()
&& !tc.Class("OUString").Namespace("rtl").GlobalNamespace()
&& !tc.Class("OString").Namespace("rtl").GlobalNamespace()
&& !tc.Class("BinaryAny")
&& !tc.Class("Reference")
&& !tc.Class("SvRef").Namespace("tools").GlobalNamespace()
&& !tc.ClassOrStruct("sk_sp") // skia shared pointer
&& !tc.ClassOrStruct("VclPtr")
&& !tc.Typedef("IterString") // SalInstanceTreeView::IterString
&& !tc.Typedef("svtree_render_args")
&& !tc.Typedef("render_args") // weld::ComboBox::render_args
;
// clang-format on
}
/// off by default because each warning needs to be hand checked to ensure it is not a false+
loplugin::Plugin::Registration<MoveIt> moveit("moveit", false);
} // namespace
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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