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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 "plugin.hxx"
// Similar to GCC "warning: ‘void* memset(void*, int, size_t)’ writing to an object of non-trivial
// type ‘...’; use assignment instead [-Wclass-memaccess]", but looking through toplevel cast to
// void* and taking arrays into account in addition to pointers. (Clang has
// -Wdynamic-class-memaccess, but that only warns about memset overwriting a vtable pointer. GCC
// deliberately does not warn when there is a toplevel cast to void*, see
// <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81327> "[8 Regression] cast to void* does not
// suppress -Wclass-memaccess".)
namespace
{
class ClassMemAccess final : public loplugin::FilteringPlugin<ClassMemAccess>
{
public:
explicit ClassMemAccess(loplugin::InstantiationData const& data)
: FilteringPlugin(data)
{
}
bool VisitCallExpr(CallExpr const* expr)
{
if (ignoreLocation(expr))
{
return true;
}
auto const fdecl = expr->getDirectCallee();
if (fdecl == nullptr)
{
return true;
}
auto dc = loplugin::DeclCheck(fdecl).Function("memset");
if (!(dc.GlobalNamespace() || dc.StdNamespace()))
{
return true;
}
if (expr->getNumArgs() != 3)
{
if (isDebugMode())
{
report(DiagnosticsEngine::Fatal,
"unexpected call to %0 with %1 instead of 3 arguments", expr->getExprLoc())
<< fdecl << expr->getNumArgs() << expr->getSourceRange();
report(DiagnosticsEngine::Note, "%0 declared here", fdecl->getLocation())
<< fdecl << fdecl->getSourceRange();
}
return true;
}
auto e = expr->getArg(0)->IgnoreParenImpCasts();
while (auto const cast = dyn_cast<ExplicitCastExpr>(e))
{
if (!loplugin::TypeCheck(cast->getTypeAsWritten()).Pointer().Void())
{
break;
}
e = cast->getSubExprAsWritten()->IgnoreParenImpCasts();
}
QualType t;
if (auto const t1 = e->getType()->getAs<clang::PointerType>())
{
t = t1->getPointeeType();
}
else if (e->getType()->isArrayType())
{
t = e->getType();
while (auto const t2 = t->getAsArrayTypeUnsafe())
{
t = t2->getElementType();
}
}
else
{
if (isDebugMode())
{
report(DiagnosticsEngine::Fatal,
"unexpected call to %0 with first argument of non-pointer type %1",
expr->getExprLoc())
<< fdecl << e->getType() << expr->getSourceRange();
report(DiagnosticsEngine::Note, "%0 declared here", fdecl->getLocation())
<< fdecl << fdecl->getSourceRange();
}
return true;
}
auto const decl = t->getAsCXXRecordDecl();
if (decl == nullptr)
{
return true;
}
if (!decl->isCompleteDefinition())
{
return true; // conservatively assume it may be trivial
}
if (decl->isTrivial())
{
return true;
}
report(DiagnosticsEngine::Warning,
"%0 writing to an object of non-trivial type %1; use assignment instead",
expr->getExprLoc())
<< fdecl << decl << expr->getSourceRange();
return true;
}
bool preRun() override { return compiler.getLangOpts().CPlusPlus; }
private:
void run() override
{
if (preRun())
{
TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
}
}
};
loplugin::Plugin::Registration<ClassMemAccess> classmemaccess("classmemaccess");
}
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
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