Impressum stringviewparam.cxx Sprache: C

/* -*- 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/.
*/

#include <cassert>
#include <set>
#include <vector>

#include "config_clang.h"

#include "check.hxx"
#include "functionaddress.hxx"
#include "plugin.hxx"

// Find functions that take rtl::O[U]String parameters that can be generalized to take
// std::[u16]string_view instead.

//TODO: At least theoretically, there are issues with replacing parameters that are being assigned
// to, as in
//
//  void f(OUString s) {
//    {
//      OUString t = ...;
//      s = t;
//    }
//    ... use s ... // if s is now std::u16string_view, it points into destroyed contents of t
//  }

namespace
{
bool hasSalDllpublicExportAttr(FunctionDecl const* decl)
{
    if (auto const attr = decl->getAttr<VisibilityAttr>())
    {
        return attr->getVisibility() == VisibilityAttr::Default;
    }
    return decl->hasAttr<DLLExportAttr>();
}

enum class StringType
{
    None,
    RtlOstring,
    RtlOustring
};

StringType relevantStringType(QualType type)
{
    loplugin::TypeCheck const c(type);
    if (c.Class("OString").Namespace("rtl"))
    {
        return StringType::RtlOstring;
    }
    else if (c.Class("OUString").Namespace("rtl"))
    {
        return StringType::RtlOustring;
    }
    else
    {
        return StringType::None;
    }
}

bool relevantParmVarDecl(ParmVarDecl const* decl)
{
    auto const t1 = decl->getType();
    if (auto const t2 = t1->getAs<LValueReferenceType>())
    {
        if (!t2->getPointeeType().isConstQualified())
        {
            return false;
        }
    }
    if (relevantStringType(t1.getNonReferenceType()) == StringType::None)
    {
        return false;
    }
    if (decl->hasAttr<UnusedAttr>())
    {
        return false;
    }
    return true;
}

DeclRefExpr const* relevantDeclRefExpr(Expr const* expr)
{
    //TODO: Look through BO_Comma and AbstractConditionalOperator
    auto const e = dyn_cast<DeclRefExpr>(expr->IgnoreParenImpCasts());
    if (e == nullptr)
    {
        return nullptr;
    }
    auto const d = dyn_cast<ParmVarDecl>(e->getDecl());
    if (d == nullptr)
    {
        return nullptr;
    }
    if (!relevantParmVarDecl(d))
    {
        return nullptr;
    }
    return e;
}

bool isStringView(QualType qt)
{
    return bool(loplugin::TypeCheck(qt).ClassOrStruct("basic_string_view").StdNamespace());
}

DeclRefExpr const* relevantImplicitCastExpr(ImplicitCastExpr const* expr)
{
    if (!isStringView(expr->getType()))
    {
        return nullptr;
    }
    return relevantDeclRefExpr(expr->getSubExprAsWritten());
}

DeclRefExpr const* relevantCXXMemberCallExpr(CXXMemberCallExpr const* expr)
{
    StringType t = relevantStringType(expr->getObjectType());
    if (t == StringType::None)
    {
        return nullptr;
    }
    bool good = false;
    auto const d = expr->getMethodDecl();
    if (d->getOverloadedOperator() == OO_Subscript)
    {
        good = true;
    }
    else if (auto const i = d->getIdentifier())
    {
        auto const n = i->getName();
        if (!(n == "getLength" || n == "getStr" || n == "convertToString" || n == "replace"
              || n == "replaceAll" || n == "replaceAt" || n == "replaceFirst"
              || n == "toAsciiLowerCase" || n == "toAsciiUpperCase" || n == "toUtf8"
              || n == "startsWithIgnoreAsciiCase" || n == "toUInt64" || n == "toFloat"
              || n == "toBoolean"))
        {
            good = true;
        }
#if 0
        //TODO: rtl::O[U]String::getLength would be awkward to replace with
        // std::[u16]string_view::length/size due to the sal_Int32 vs. std::size_t return type
        // mismatch (C++20 ssize might make that easier, though); and while rtl::OString::getStr is
        // documented to be NUL-terminated (so not eligible for replacement with
        // std::string_view::data in general), rtl::OUString::getStr is not (so should be eligible
        // for replacement with std::u16string_view::data, but some call sites might nevertheless
        // incorrectly rely on NUL termination, so any replacement would need careful review):
        if (n == "getLength" || (t == StringType::RtlOustring && n == "getStr"))
        {
            good = true;
        }
#endif
    }
    if (!good)
    {
        return nullptr;
    }
    return relevantDeclRefExpr(expr->getImplicitObjectArgument());
}

SmallVector<DeclRefExpr const*, 2> wrap(DeclRefExpr const* expr)
{
    if (expr == nullptr)
    {
        return {};
    }
    return { expr };
}

SmallVector<DeclRefExpr const*, 2> relevantCXXOperatorCallExpr(CXXOperatorCallExpr const* expr)
{
    auto const op = expr->getOperator();
    if (op == OO_Subscript)
    {
        auto const e = expr->getArg(0);
        if (relevantStringType(e->getType()) == StringType::None)
        {
            return {};
        }
        return wrap(relevantDeclRefExpr(e));
    }
    if (expr->isComparisonOp() || (op == OO_Plus && expr->getNumArgs() == 2))
    {
        SmallVector<DeclRefExpr const*, 2> v;
        if (auto const e = relevantDeclRefExpr(expr->getArg(0)))
        {
            v.push_back(e);
        }
        if (auto const e = relevantDeclRefExpr(expr->getArg(1)))
        {
            v.push_back(e);
        }
        return v;
    }
    if (op == OO_PlusEqual)
    {
        if (relevantStringType(expr->getArg(0)->getType()) != StringType::RtlOustring)
        {
            return {};
        }
        return wrap(relevantDeclRefExpr(expr->getArg(1)));
    }
    return {};
}

//TODO: current implementation is not at all general, just tests what we encounter in practice:
bool hasStringViewOverload(ParmVarDecl const* decl)
{
    auto const d1 = cast<FunctionDecl>(decl->getDeclContext());
    auto const ctx = d1->getDeclContext();
    if (!ctx->isLookupContext())
    {
        return false;
    }
    auto const res = ctx->lookup(d1->getDeclName());
    auto const idx = decl->getFunctionScopeIndex();
    auto const n = d1->getNumParams();
    assert(n > idx);
    for (auto i = res.begin(); i != res.end(); ++i)
    {
        auto const d2 = dyn_cast<FunctionDecl>(*i);
        if (d2 == nullptr)
        {
            continue;
        }
        if (d2->getNumParams() != n)
        {
            continue;
        }
        auto match = true;
        for (unsigned j = 0; j != n; ++j)
        {
            if (j == idx)
            {
                //TODO: check for exactly std::string_view or std::u16string_view:
                if (!isStringView(d2->getParamDecl(j)->getType()))
                {
                    match = false;
                    break;
                }
            }
            else if (d1->getParamDecl(j)->getType().getCanonicalType()
                     != d2->getParamDecl(j)->getType().getCanonicalType())
            {
                match = false;
                break;
            }
        }
        if (match)
        {
            return true;
        }
    }
    return false;
}

class StringViewParam final
    : public loplugin::FunctionAddress<loplugin::FilteringPlugin<StringViewParam>>
{
public:
    explicit StringViewParam(loplugin::InstantiationData const& data)
        : FunctionAddress(data)
    {
    }

    //TODO: Also check lambdas
    bool TraverseFunctionDecl(FunctionDecl* decl)
    {
        if (ignoreLocation(decl))
        {
            return true;
        }
        if (!relevantFunctionDecl(decl))
        {
            return FunctionAddress::TraverseFunctionDecl(decl);
        }
        auto const oldParams = currentParams_;
        auto const n = decl->getNumParams();
        for (unsigned i = 0; i != n; ++i)
        {
            auto const d = decl->getParamDecl(i);
            if (relevantParmVarDecl(d))
            {
                currentParams_.insert(d);
            }
        }
        auto const ret = FunctionAddress::TraverseFunctionDecl(decl);
        if (ret)
        {
            for (unsigned i = 0; i != n; ++i)
            {
                auto const d1 = decl->getParamDecl(i);
                if (currentParams_.find(d1) == currentParams_.end())
                {
                    continue;
                }
                if (containsPreprocessingConditionalInclusion(decl->getSourceRange()))
                {
                    break;
                }
                badParams_.push_back(d1);
            }
        }
        currentParams_ = oldParams;
        return ret;
    }

    bool TraverseCXXMethodDecl(CXXMethodDecl* decl)
    {
        if (ignoreLocation(decl))
        {
            return true;
        }
        if (!relevantFunctionDecl(decl))
        {
            return FunctionAddress::TraverseCXXMethodDecl(decl);
        }
        auto const oldParams = currentParams_;
        auto const n = decl->getNumParams();
        for (unsigned i = 0; i != n; ++i)
        {
            auto const d = decl->getParamDecl(i);
            if (relevantParmVarDecl(d))
            {
                currentParams_.insert(d);
            }
        }
        auto const ret = FunctionAddress::TraverseCXXMethodDecl(decl);
        if (ret)
        {
            for (unsigned i = 0; i != n; ++i)
            {
                auto const d1 = decl->getParamDecl(i);
                if (currentParams_.find(d1) == currentParams_.end())
                {
                    continue;
                }
                if (containsPreprocessingConditionalInclusion(decl->getSourceRange()))
                {
                    break;
                }
                badParams_.push_back(d1);
            }
        }
        currentParams_ = oldParams;
        return ret;
    }

    bool TraverseCXXConstructorDecl(CXXConstructorDecl* decl)
    {
        if (ignoreLocation(decl))
        {
            return true;
        }
        if (!relevantFunctionDecl(decl))
        {
            return FunctionAddress::TraverseCXXConstructorDecl(decl);
        }
        auto const oldParams = currentParams_;
        auto const n = decl->getNumParams();
        for (unsigned i = 0; i != n; ++i)
        {
            auto const d = decl->getParamDecl(i);
            if (relevantParmVarDecl(d))
            {
                currentParams_.insert(d);
            }
        }
        auto const ret = FunctionAddress::TraverseCXXConstructorDecl(decl);
        if (ret)
        {
            for (unsigned i = 0; i != n; ++i)
            {
                auto const d1 = decl->getParamDecl(i);
                if (currentParams_.find(d1) == currentParams_.end())
                {
                    continue;
                }
                if (containsPreprocessingConditionalInclusion(decl->getSourceRange()))
                {
                    break;
                }
                badParams_.push_back(d1);
            }
        }
        currentParams_ = oldParams;
        return ret;
    }

    bool TraverseImplicitCastExpr(ImplicitCastExpr* expr)
    {
        if (ignoreLocation(expr))
        {
            return true;
        }
        auto const e = relevantImplicitCastExpr(expr);
        if (e == nullptr)
        {
            return FunctionAddress::TraverseImplicitCastExpr(expr);
        }
        currentGoodUses_.insert(e);
        auto const ret = FunctionAddress::TraverseImplicitCastExpr(expr);
        currentGoodUses_.erase(e);
        return ret;
    }

    bool TraverseCXXMemberCallExpr(CXXMemberCallExpr* expr)
    {
        if (ignoreLocation(expr))
        {
            return true;
        }
        auto const e = relevantCXXMemberCallExpr(expr);
        if (e == nullptr)
        {
            return FunctionAddress::TraverseCXXMemberCallExpr(expr);
        }
        currentGoodUses_.insert(e);
        auto const ret = FunctionAddress::TraverseCXXMemberCallExpr(expr);
        currentGoodUses_.erase(e);
        return ret;
    }

    bool TraverseCXXOperatorCallExpr(CXXOperatorCallExpr* expr)
    {
        if (ignoreLocation(expr))
        {
            return true;
        }
        auto const es = relevantCXXOperatorCallExpr(expr);
        if (es.empty())
        {
            return FunctionAddress::TraverseCXXOperatorCallExpr(expr);
        }
        currentGoodUses_.insert(es.begin(), es.end());
        auto const ret = FunctionAddress::TraverseCXXOperatorCallExpr(expr);
        for (auto const i : es)
        {
            currentGoodUses_.erase(i);
        }
        return ret;
    }

    bool VisitDeclRefExpr(DeclRefExpr* expr)
    {
        if (!FunctionAddress::VisitDeclRefExpr(expr))
        {
            return false;
        }
        if (ignoreLocation(expr))
        {
            return true;
        }
        if (currentGoodUses_.find(expr) != currentGoodUses_.end())
        {
            return true;
        }
        if (auto const d = dyn_cast<ParmVarDecl>(expr->getDecl()))
        {
            currentParams_.erase(d);
        }
        return true;
    }

private:
    void run() override
    {
        if (!compiler.getLangOpts().CPlusPlus)
        {
            return;
        }
        if (compiler.getPreprocessor().getIdentifierInfo("NDEBUG")->hasMacroDefinition())
        {
            return;
        }
        StringRef fn(handler.getMainFileName());
        // leave the string QA tests alone
        if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sal/qa/"))
        {
            return;
        }
        if (!TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()))
        {
            return;
        }
        auto const ignoredFns = getFunctionsWithAddressTaken();
        for (auto const i : badParams_)
        {
            auto const d1 = cast<FunctionDecl>(i->getDeclContext());
            if (ignoredFns.find(d1) != ignoredFns.end())
            {
                continue;
            }
            if (hasStringViewOverload(i))
            {
                continue;
            }
            auto const t = relevantStringType(i->getType().getNonReferenceType());
            assert(t != StringType::None);
            report(DiagnosticsEngine::Warning,
                   "replace function parameter of type %0 with "
                   "'%select{std::string_view|std::u16string_view}1'",
                   i->getLocation())
                << i->getType() << (int(t) - 1) << i->getSourceRange();
            for (auto d2 = d1;;)
            {
                d2 = d2->getPreviousDecl();
                if (d2 == nullptr)
                {
                    break;
                }
                auto const d3 = d2->getParamDecl(i->getFunctionScopeIndex());
                report(DiagnosticsEngine::Note, "previous declaration is here", d3->getLocation())
                    << d3->getSourceRange();
            }
        }
    }

    bool relevantFunctionDecl(FunctionDecl const* decl)
    {
        if (!decl->doesThisDeclarationHaveABody())
        {
            return false;
        }
        if (decl->getBody() == nullptr) // unparsed template
        {
            return false;
        }
        if (auto const d = dyn_cast<CXXMethodDecl>(decl))
        {
            if (d->isVirtual())
            {
                return false;
            }
        }
        if (decl->isFunctionTemplateSpecialization())
        {
            return false;
        }
        if (decl->getLocation().isMacroID())
        {
            return false;
        }
        // Filter out functions that are presumably meant to be called dynamically (e.g., via
        // dlopen, or backwards compatibility stubs in cppuhelper/cppu/sal compat.cxx):
        if (decl->getPreviousDecl() == nullptr && !decl->isInlined()
            && hasSalDllpublicExportAttr(decl)
            && compiler.getSourceManager().isInMainFile(decl->getLocation()))
        {
            return false;
        }
        if (isInUnoIncludeFile(compiler.getSourceManager().getSpellingLoc(decl->getLocation())))
        {
            return false;
        }
        return true;
    }

    std::set<ParmVarDecl const*> currentParams_;
    std::set<DeclRefExpr const*> currentGoodUses_;
    std::vector<ParmVarDecl const*> badParams_;
};

static loplugin::Plugin::Registration<StringViewParam> reg("stringviewparam");
}

/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */

quality94%

¤ Dauer der Verarbeitung: 0.17 Sekunden ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.