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/* -*- 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 "check.hxx"
#include "compat.hxx"
#include "plugin.hxx"
#include <iostream>
#include <fstream>
#include <unordered_set>
#include <vector>
namespace
{
class RedundantFCast final : public loplugin::FilteringPlugin<RedundantFCast>
{
public:
explicit RedundantFCast(loplugin::InstantiationData const& data)
: FilteringPlugin(data)
{
}
bool VisitReturnStmt(ReturnStmt const* returnStmt)
{
if (ignoreLocation(returnStmt))
return true;
Expr const* expr = returnStmt->getRetValue();
if (!expr)
return true;
if (auto exprWithCleanups = dyn_cast<ExprWithCleanups>(expr))
expr = exprWithCleanups->getSubExpr();
if (auto cxxConstructExpr = dyn_cast<CXXConstructExpr>(expr))
{
if (cxxConstructExpr->getNumArgs() != 1)
return true;
expr = cxxConstructExpr->getArg(0);
}
if (auto materializeTemporaryExpr = dyn_cast<MaterializeTemporaryExpr>(expr))
expr = compat::getSubExpr(materializeTemporaryExpr);
auto cxxFunctionalCastExpr = dyn_cast<CXXFunctionalCastExpr>(expr);
if (!cxxFunctionalCastExpr)
return true;
auto const t1 = cxxFunctionalCastExpr->getTypeAsWritten();
auto const t2 = compat::getSubExprAsWritten(cxxFunctionalCastExpr)->getType();
if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
return true;
if (!loplugin::isOkToRemoveArithmeticCast(compiler.getASTContext(), t1, t2,
cxxFunctionalCastExpr->getSubExpr()))
{
return true;
}
if (m_Seen.insert(cxxFunctionalCastExpr->getExprLoc()).second)
report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
cxxFunctionalCastExpr->getExprLoc())
<< t2 << t1 << cxxFunctionalCastExpr->getSourceRange();
return true;
}
/* Check for the creation of unnecessary temporaries when calling a method that takes a param by const & */
bool VisitCallExpr(CallExpr const* callExpr)
{
if (ignoreLocation(callExpr))
return true;
const FunctionDecl* functionDecl;
if (isa<CXXMemberCallExpr>(callExpr))
functionDecl = dyn_cast<CXXMemberCallExpr>(callExpr)->getMethodDecl();
else
functionDecl = callExpr->getDirectCallee();
if (!functionDecl)
return true;
unsigned len = std::min(callExpr->getNumArgs(), functionDecl->getNumParams());
for (unsigned i = 0; i < len; ++i)
{
// check if param is const&
auto param = functionDecl->getParamDecl(i);
auto lvalueType = param->getType()->getAs<LValueReferenceType>();
if (!lvalueType)
continue;
if (!lvalueType->getPointeeType().isConstQualified())
continue;
auto paramClassOrStructType = lvalueType->getPointeeType()->getAs<RecordType>();
if (!paramClassOrStructType)
continue;
// check for temporary and functional cast in argument expression
auto arg = callExpr->getArg(i)->IgnoreImpCasts();
auto materializeTemporaryExpr = dyn_cast<MaterializeTemporaryExpr>(arg);
if (!materializeTemporaryExpr)
continue;
auto functionalCast = dyn_cast<CXXFunctionalCastExpr>(
compat::getSubExpr(materializeTemporaryExpr)->IgnoreImpCasts());
if (!functionalCast)
continue;
auto const t1 = functionalCast->getTypeAsWritten();
auto const t2 = compat::getSubExprAsWritten(functionalCast)->getType();
if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
continue;
// Check that the underlying expression is of the same class/struct type as the param i.e. that we are not instantiating
// something useful
if (t1.getCanonicalType().getTypePtr() != paramClassOrStructType)
continue;
// Don't warn about (necessary) cast from braced-init-list in non-deduced contexts:
if (lvalueType->getPointeeType()->getAs<SubstTemplateTypeParmType>() != nullptr
&& loplugin::TypeCheck(t1).ClassOrStruct("initializer_list").StdNamespace()
&& isa<CXXStdInitializerListExpr>(compat::getSubExprAsWritten(functionalCast)))
{
continue;
}
if (m_Seen.insert(arg->getExprLoc()).second)
{
report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
arg->getExprLoc())
<< t2 << t1 << arg->getSourceRange();
report(DiagnosticsEngine::Note, "in call to method here", param->getLocation())
<< param->getSourceRange();
}
}
return true;
}
/* Check for the creation of unnecessary temporaries when calling a constructor that takes a param by const & */
bool VisitCXXConstructExpr(CXXConstructExpr const* callExpr)
{
if (ignoreLocation(callExpr))
return true;
const CXXConstructorDecl* functionDecl = callExpr->getConstructor();
unsigned len = std::min(callExpr->getNumArgs(), functionDecl->getNumParams());
for (unsigned i = 0; i < len; ++i)
{
// check if param is const&
auto param = functionDecl->getParamDecl(i);
auto rvalueType = param->getType()->getAs<RValueReferenceType>();
if (!rvalueType)
{
auto lvalueType = param->getType()->getAs<LValueReferenceType>();
if (!lvalueType)
continue;
if (!lvalueType->getPointeeType().isConstQualified())
continue;
}
auto valueType = param->getType()->getAs<ReferenceType>();
auto paramClassOrStructType = valueType->getPointeeType()->getAs<RecordType>();
if (!paramClassOrStructType)
continue;
// check for temporary and functional cast in argument expression
auto arg = compat::IgnoreParenImplicit(callExpr->getArg(i));
auto functionalCast = dyn_cast<CXXFunctionalCastExpr>(arg);
if (!functionalCast)
continue;
auto const t1 = functionalCast->getTypeAsWritten();
auto const t2 = compat::getSubExprAsWritten(functionalCast)->getType();
if (t1.getCanonicalType().getTypePtr() != t2.getCanonicalType().getTypePtr())
continue;
// Check that the underlying expression is of the same class/struct type as the param i.e. that we are not instantiating
// something useful
if (t1.getCanonicalType().getTypePtr() != paramClassOrStructType)
continue;
if (rvalueType)
{
// constructing a temporary to pass to a && argument is fine. But we will see that in the VisitFunctionalCast
// method below and generate a warning. And we don't have enough context there to determine that we're
// doing the wrong thing. So add the expression to the m_Seen list here to prevent that warning.
m_Seen.insert(functionalCast->getExprLoc());
continue;
}
if (m_Seen.insert(arg->getExprLoc()).second)
{
report(DiagnosticsEngine::Warning,
"redundant functional cast from %0 to %1 in construct expression",
arg->getExprLoc())
<< t2 << t1 << arg->getSourceRange();
report(DiagnosticsEngine::Note, "in call to method here", param->getLocation())
<< param->getSourceRange();
}
}
return true;
}
// Find redundant cast to std::function, where clang reports
// two different types for the inner and outer
bool isRedundantStdFunctionCast(CXXFunctionalCastExpr const* expr)
{
bool deduced = false;
QualType target;
auto const written = expr->getTypeAsWritten();
if (auto const t1 = written->getAs<DeducedTemplateSpecializationType>())
{
auto const decl = t1->getTemplateName().getAsTemplateDecl();
if (!decl)
{
return false;
}
if (!loplugin::DeclCheck(decl->getTemplatedDecl())
.ClassOrStruct("function")
.StdNamespace())
{
return false;
}
deduced = true;
}
else if (auto const t2 = written->getAs<TemplateSpecializationType>())
{
auto const decl = t2->getTemplateName().getAsTemplateDecl();
if (!decl)
{
return false;
}
if (!loplugin::DeclCheck(decl->getTemplatedDecl())
.ClassOrStruct("function")
.StdNamespace())
{
return false;
}
if (t2->getNumArgs() != 1)
{
if (isDebugMode())
{
report(DiagnosticsEngine::Fatal,
"TODO: unexpected std::function with %0 template arguments",
expr->getExprLoc())
<< t2->getNumArgs() << expr->getSourceRange();
}
return false;
}
if (t2->getArg(0).getKind() != TemplateArgument::Type)
{
if (isDebugMode())
{
report(DiagnosticsEngine::Fatal,
"TODO: unexpected std::function with non-type template argument",
expr->getExprLoc())
<< expr->getSourceRange();
}
return false;
}
target = t2->getArg(0).getAsType();
}
else
{
return false;
}
auto cxxConstruct
= dyn_cast<CXXConstructExpr>(compat::IgnoreParenImplicit(expr->getSubExpr()));
if (!cxxConstruct)
return false;
auto const lambda
= dyn_cast<LambdaExpr>(compat::IgnoreParenImplicit(cxxConstruct->getArg(0)));
if (!lambda)
return false;
if (deduced)
// std::function([...](Args)->Ret{...}) should always be redundant:
return true;
auto const decl = lambda->getCallOperator();
std::vector<QualType> args;
for (unsigned i = 0; i != decl->getNumParams(); ++i)
{
args.push_back(decl->getParamDecl(i)->getType());
}
auto const source
= compiler.getASTContext().getFunctionType(decl->getReturnType(), args, {});
// std::function<Ret1(Args1)>([...](Args2)->Ret2{...}) is redundant if target Ret1(Args1)
// matches source Ret2(Args2):
return target.getCanonicalType() == source.getCanonicalType();
}
bool VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr const* expr)
{
if (ignoreLocation(expr))
return true;
// specifying the name for an init-list is necessary sometimes
if (isa<InitListExpr>(compat::IgnoreParenImplicit(expr->getSubExpr())))
return true;
if (isa<CXXStdInitializerListExpr>(compat::IgnoreParenImplicit(expr->getSubExpr())))
return true;
auto const t1 = expr->getTypeAsWritten();
auto const t2 = compat::getSubExprAsWritten(expr)->getType();
if (!(t1.getCanonicalType().getTypePtr() == t2.getCanonicalType().getTypePtr()
|| isRedundantStdFunctionCast(expr)))
{
return true;
}
// (a) we do a lot of int/sal_Int32 kind of casts which might be platform necessary?
// (b) we do bool/bool casts in unit tests to avoid one of the other plugins
// so just ignore this kind of thing for now
if (const auto* BT = dyn_cast<BuiltinType>(t1->getUnqualifiedDesugaredType()))
{
auto k = BT->getKind();
if (k == BuiltinType::Double || k == BuiltinType::Float
|| (k >= BuiltinType::Bool && k <= BuiltinType::Int128))
return true;
}
if (const auto* BT = dyn_cast<BuiltinType>(t2->getUnqualifiedDesugaredType()))
{
auto k = BT->getKind();
if (k == BuiltinType::Double || k == BuiltinType::Float
|| (k >= BuiltinType::Bool && k <= BuiltinType::Int128))
return true;
}
auto tc = loplugin::TypeCheck(t1);
if (tc.Typedef("sal_Int32").GlobalNamespace())
return true;
if (m_Seen.insert(expr->getExprLoc()).second)
report(DiagnosticsEngine::Warning, "redundant functional cast from %0 to %1",
expr->getExprLoc())
<< t2 << t1 << expr->getSourceRange();
return true;
}
bool preRun() override
{
if (!compiler.getLangOpts().CPlusPlus)
return false;
std::string fn = handler.getMainFileName().str();
loplugin::normalizeDotDotInFilePath(fn);
// necessary on some other platforms
if (fn == SRCDIR "/sal/osl/unx/socket.cxx")
return false;
// compile-time check of constant
if (fn == SRCDIR "/bridges/source/jni_uno/jni_bridge.cxx")
return false;
// TODO constructing a temporary to pass to a && param
if (fn == SRCDIR "/sc/source/ui/view/viewfunc.cxx")
return false;
// tdf#145203: FIREBIRD cannot create a table
if (fn == SRCDIR "/connectivity/source/drivers/firebird/DatabaseMetaData.cxx")
return false;
return true;
}
void run() override
{
if (preRun())
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
std::unordered_set<SourceLocation> m_Seen;
};
static loplugin::Plugin::Registration<RedundantFCast> redundantfcast("redundantfcast");
} // namespace
#endif // LO_CLANG_SHARED_PLUGINS
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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