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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 <cassert>
#include "check.hxx"
#include "plugin.hxx"
// Warn about checks whether a container is empty done via an (expensive) call to obtain the
// container's size. For now only handles cases involving strlen.
namespace
{
BinaryOperatorKind reverse(BinaryOperatorKind op)
{
switch (op)
{
case BO_LT:
return BO_GE;
case BO_GT:
return BO_LE;
case BO_LE:
return BO_GT;
case BO_GE:
return BO_LT;
case BO_EQ:
case BO_NE:
return op;
default:
abort();
}
}
class Empty : public loplugin::FilteringPlugin<Empty>
{
public:
explicit Empty(loplugin::InstantiationData const& data)
: FilteringPlugin(data)
{
}
bool VisitBinaryOperator(BinaryOperator const* expr)
{
if (expr->isRelationalOp() || expr->isEqualityOp())
{
visitComparison(expr);
}
return true;
}
private:
void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
void visitComparison(BinaryOperator const* expr, CallExpr const* lhs, Expr const* rhs,
BinaryOperatorKind op)
{
auto const fdecl = lhs->getDirectCallee();
if (fdecl == nullptr)
{
return;
}
loplugin::DeclCheck dc(fdecl);
if (!(dc.Function("strlen").StdNamespace() || dc.Function("strlen").GlobalNamespace()))
{
return;
}
if (rhs->isValueDependent())
{
return;
}
auto const val = rhs->getIntegerConstantExpr(compiler.getASTContext());
if (!val)
{
return;
}
switch (op)
{
case BO_LT:
if (val->getExtValue() == 1)
{
report(DiagnosticsEngine::Warning,
"replace a comparison like 'strlen(e) < 1' with 'e[0] == '\\0''",
expr->getExprLoc())
<< expr->getSourceRange();
}
break;
case BO_GT:
if (val->getExtValue() == 0)
{
report(DiagnosticsEngine::Warning,
"replace a comparison like 'strlen(e) > 0' with 'e[0] != '\\0''",
expr->getExprLoc())
<< expr->getSourceRange();
}
break;
case BO_LE:
if (val->getExtValue() == 0)
{
report(DiagnosticsEngine::Warning,
"replace a comparison like 'strlen(e) <= 0' with 'e[0] == '\\0''",
expr->getExprLoc())
<< expr->getSourceRange();
}
break;
case BO_GE:
if (val->getExtValue() == 1)
{
report(DiagnosticsEngine::Warning,
"replace a comparison like 'strlen(e) >= 1' with 'e[0] != '\\0''",
expr->getExprLoc())
<< expr->getSourceRange();
}
break;
case BO_EQ:
if (val->getExtValue() == 0)
{
report(DiagnosticsEngine::Warning,
"replace a comparison like 'strlen(e) == 0' with 'e[0] == '\\0''",
expr->getExprLoc())
<< expr->getSourceRange();
}
break;
case BO_NE:
if (val->getExtValue() == 0)
{
report(DiagnosticsEngine::Warning,
"replace a comparison like 'strlen(e) != 0' with 'e[0] != '\\0''",
expr->getExprLoc())
<< expr->getSourceRange();
}
break;
default:
assert(false);
}
}
void visitComparison(BinaryOperator const* expr)
{
if (ignoreLocation(expr))
{
return;
}
if (auto const call = dyn_cast<CallExpr>(expr->getLHS()->IgnoreParenImpCasts()))
{
visitComparison(expr, call, expr->getRHS(), expr->getOpcode());
}
else if (auto const call = dyn_cast<CallExpr>(expr->getRHS()->IgnoreParenImpCasts()))
{
visitComparison(expr, call, expr->getLHS(), reverse(expr->getOpcode()));
}
}
};
loplugin::Plugin::Registration<Empty> emptyRegistration("empty");
}
#endif // LO_CLANG_SHARED_PLUGINS
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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