Adding upstream version 1:7.0.4.upstream/1%7.0.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 595 insertions, 0 deletions

diff --git a/compilerplugins/clang/constparams.cxx b/compilerplugins/clang/constparams.cxx
new file mode 100644
index 000000000..805949518
--- /dev/null
+++ b/compilerplugins/clang/constparams.cxx
@@ -0,0 +1,595 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * 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 <algorithm>
+#include <string>
+#include <unordered_set>
+#include <unordered_map>
+#include <iostream>
+
+#include "config_clang.h"
+
+#include "plugin.hxx"
+#include "compat.hxx"
+#include "check.hxx"
+#include "functionaddress.hxx"
+
+#if CLANG_VERSION >= 110000
+#include "clang/AST/ParentMapContext.h"
+#endif
+
+/**
+   Find pointer and reference params that can be declared const.
+
+   This is not a sophisticated analysis. It deliberately skips all of the hard cases for now.
+   It is an exercise in getting the most benefit for the least effort.
+*/
+namespace
+{
+
+class ConstParams:
+    public loplugin::FunctionAddress<loplugin::FilteringPlugin<ConstParams>>
+{
+public:
+    explicit ConstParams(loplugin::InstantiationData const & data): FunctionAddress(data) {}
+
+    virtual void run() override {
+        std::string fn(handler.getMainFileName());
+        loplugin::normalizeDotDotInFilePath(fn);
+        if (loplugin::hasPathnamePrefix(fn, SRCDIR "/sal/")
+            || fn == SRCDIR "/jurt/source/pipe/staticsalhack.cxx"
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/bridges/")
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/binaryurp/")
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/stoc/")
+            || loplugin::hasPathnamePrefix(fn, WORKDIR "/YaccTarget/unoidl/source/sourceprovider-parser.cxx")
+            // some weird calling through a function pointer
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/svtools/source/table/defaultinputhandler.cxx")
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/sdext/source/pdfimport/test/pdfunzip.cxx")
+            // windows only
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/basic/source/sbx/sbxdec.cxx")
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/sfx2/source/doc/syspath.cxx")
+            // ignore this for now
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/libreofficekit")
+            // FunctionAddress not working well enough here
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/pyuno/source/module/pyuno_struct.cxx")
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/pyuno/source/module/pyuno.cxx")
+            || loplugin::hasPathnamePrefix(fn, SRCDIR "/sw/source/filter/ascii/ascatr.cxx")
+            )
+            return;
+
+        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+
+        for (const ParmVarDecl *pParmVarDecl : interestingParamSet) {
+            auto functionDecl = parmToFunction[pParmVarDecl];
+            auto canonicalDecl = functionDecl->getCanonicalDecl();
+            if (getFunctionsWithAddressTaken().find(canonicalDecl)
+                != getFunctionsWithAddressTaken().end())
+            {
+                continue;
+            }
+            std::string fname = functionDecl->getQualifiedNameAsString();
+            report(
+                DiagnosticsEngine::Warning,
+                "this parameter can be const %0",
+                compat::getBeginLoc(pParmVarDecl))
+                << fname << pParmVarDecl->getSourceRange();
+            if (canonicalDecl->getLocation() != functionDecl->getLocation()) {
+                unsigned idx = pParmVarDecl->getFunctionScopeIndex();
+                const ParmVarDecl* pOther = canonicalDecl->getParamDecl(idx);
+                report(
+                    DiagnosticsEngine::Note,
+                    "canonical parameter declaration here",
+                    compat::getBeginLoc(pOther))
+                    << pOther->getSourceRange();
+            }
+            //functionDecl->dump();
+        }
+    }
+
+    bool TraverseFunctionDecl(FunctionDecl *);
+    bool TraverseCXXMethodDecl(CXXMethodDecl * f);
+    bool TraverseCXXConstructorDecl(CXXConstructorDecl * f);
+    bool VisitDeclRefExpr(const DeclRefExpr *);
+
+private:
+    bool CheckTraverseFunctionDecl(FunctionDecl *);
+    bool checkIfCanBeConst(const Stmt*, const ParmVarDecl*);
+    // integral or enumeration or const * or const &
+    bool isOkForParameter(const QualType& qt);
+    bool isPointerOrReferenceToNonConst(const QualType& qt);
+
+    std::unordered_set<const ParmVarDecl*> interestingParamSet;
+    std::unordered_map<const ParmVarDecl*, const FunctionDecl*> parmToFunction;
+    FunctionDecl* currentFunctionDecl = nullptr;
+};
+
+bool ConstParams::TraverseFunctionDecl(FunctionDecl * functionDecl)
+{
+    // We cannot short-circuit the traverse here entirely without breaking the
+    // loplugin::FunctionAddress stuff.
+    auto prev = currentFunctionDecl;
+    if (CheckTraverseFunctionDecl(functionDecl))
+        currentFunctionDecl = functionDecl;
+    auto rv = FunctionAddress::TraverseFunctionDecl(functionDecl);
+    currentFunctionDecl = prev;
+    return rv;
+}
+bool ConstParams::TraverseCXXMethodDecl(CXXMethodDecl * f)
+{
+    auto prev = currentFunctionDecl;
+    if (CheckTraverseFunctionDecl(f))
+        currentFunctionDecl = f;
+    auto rv = FunctionAddress::TraverseCXXMethodDecl(f);
+    currentFunctionDecl = prev;
+    return rv;
+}
+bool ConstParams::TraverseCXXConstructorDecl(CXXConstructorDecl * f)
+{
+    auto prev = currentFunctionDecl;
+    if (CheckTraverseFunctionDecl(f))
+        currentFunctionDecl = f;
+    auto rv = FunctionAddress::TraverseCXXConstructorDecl(f);
+    currentFunctionDecl = prev;
+    return rv;
+}
+
+bool ConstParams::CheckTraverseFunctionDecl(FunctionDecl * functionDecl)
+{
+    if (ignoreLocation(functionDecl) || !functionDecl->isThisDeclarationADefinition()) {
+        return false;
+    }
+    // ignore stuff that forms part of the stable URE interface
+    if (isInUnoIncludeFile(functionDecl)) {
+        return false;
+    }
+    if (functionDecl->isDeleted())
+        return false;
+    // ignore virtual methods
+    if (isa<CXXMethodDecl>(functionDecl)
+        && dyn_cast<CXXMethodDecl>(functionDecl)->isVirtual() ) {
+        return false;
+    }
+    // ignore C main
+    if (functionDecl->isMain()) {
+        return false;
+    }
+
+    // ignore the macros from include/tools/link.hxx
+    auto canonicalDecl = functionDecl->getCanonicalDecl();
+    if (compiler.getSourceManager().isMacroBodyExpansion(compat::getBeginLoc(canonicalDecl))
+        || compiler.getSourceManager().isMacroArgExpansion(compat::getBeginLoc(canonicalDecl))) {
+        StringRef name { Lexer::getImmediateMacroName(
+                compat::getBeginLoc(canonicalDecl), compiler.getSourceManager(), compiler.getLangOpts()) };
+        if (name.startswith("DECL_LINK") || name.startswith("DECL_STATIC_LINK"))
+            return false;
+        auto loc2 = compat::getImmediateExpansionRange(compiler.getSourceManager(), compat::getBeginLoc(canonicalDecl)).first;
+        if (compiler.getSourceManager().isMacroBodyExpansion(loc2))
+        {
+            StringRef name2 { Lexer::getImmediateMacroName(
+                    loc2, compiler.getSourceManager(), compiler.getLangOpts()) };
+            if (name2.startswith("DECL_DLLPRIVATE_LINK"))
+                return false;
+        }
+    }
+
+    if (functionDecl->getIdentifier())
+    {
+        StringRef name = functionDecl->getName();
+        if (   name == "file_write"
+            || name == "SalMainPipeExchangeSignal_impl"
+            || name.startswith("SbRtl_")
+            || name == "GoNext"
+            || name == "GoPrevious"
+            || name.startswith("Read_F_")
+                // UNO component entry points
+            || name.endswith("component_getFactory")
+            || name == "egiGraphicExport"
+            || name == "etiGraphicExport"
+            || name == "epsGraphicExport"
+            // callback for some external code?
+            || name == "ScAddInAsyncCallBack"
+            // used as function pointers
+            || name == "Read_Footnote"
+            || name == "Read_Field"
+            || name == "Read_And"
+            // passed as a LINK<> to another method
+            || name == "GlobalBasicErrorHdl_Impl"
+            // template
+            || name == "extract_throw" || name == "readProp"
+            // callbacks
+            || name == "signalDragDropReceived" || name == "signal_column_clicked" || name == "signal_key_press"
+            )
+            return false;
+
+    }
+
+    std::string fqn = functionDecl->getQualifiedNameAsString();
+    if ( fqn == "connectivity::jdbc::GlobalRef::set"
+      || fqn == "(anonymous namespace)::ReorderNotifier::operator()"
+      || fqn == "static_txtattr_cast")
+        return false;
+
+    // calculate the ones we want to check
+    bool foundInterestingParam = false;
+    for (const ParmVarDecl *pParmVarDecl : functionDecl->parameters()) {
+        // ignore unused params
+        if (pParmVarDecl->getName().empty()
+            || pParmVarDecl->hasAttr<UnusedAttr>())
+            continue;
+        auto const type = loplugin::TypeCheck(pParmVarDecl->getType());
+        if (!( type.Pointer().NonConst()
+             || type.LvalueReference().NonConst()))
+            continue;
+        // since we normally can't change typedefs, just ignore them
+        if (isa<TypedefType>(pParmVarDecl->getType()))
+            continue;
+        // some typedefs turn into these
+        if (isa<DecayedType>(pParmVarDecl->getType()))
+            continue;
+        // TODO ignore these for now, has some effects I don't understand
+        if (type.Pointer().Pointer())
+            continue;
+        // const is meaningless when applied to function pointer types
+        if (pParmVarDecl->getType()->isFunctionPointerType())
+            continue;
+        interestingParamSet.insert(pParmVarDecl);
+        parmToFunction[pParmVarDecl] = functionDecl;
+        foundInterestingParam = true;
+    }
+    return foundInterestingParam;
+}
+
+bool ConstParams::VisitDeclRefExpr( const DeclRefExpr* declRefExpr )
+{
+    if (!currentFunctionDecl)
+        return true;
+    const ParmVarDecl* parmVarDecl = dyn_cast_or_null<ParmVarDecl>(declRefExpr->getDecl());
+    if (!parmVarDecl)
+        return true;
+    if (interestingParamSet.find(parmVarDecl) == interestingParamSet.end())
+        return true;
+    if (!checkIfCanBeConst(declRefExpr, parmVarDecl))
+        interestingParamSet.erase(parmVarDecl);
+    return true;
+}
+
+// Walk up from a statement that contains a DeclRefExpr, checking if the usage means that the
+// related ParamVarDecl can be const.
+bool ConstParams::checkIfCanBeConst(const Stmt* stmt, const ParmVarDecl* parmVarDecl)
+{
+    const Stmt* parent = getParentStmt( stmt );
+    if (!parent)
+    {
+        // check if we're inside a CXXCtorInitializer
+        auto parentsRange = getParents(*stmt);
+        if ( parentsRange.begin() != parentsRange.end())
+        {
+            if (auto cxxConstructorDecl = dyn_cast_or_null<CXXConstructorDecl>(parentsRange.begin()->get<Decl>()))
+            {
+                for ( auto cxxCtorInitializer : cxxConstructorDecl->inits())
+                {
+                    if ( cxxCtorInitializer->getInit() == stmt)
+                    {
+                        if (cxxCtorInitializer->isAnyMemberInitializer())
+                        {
+                            // if the member is not pointer-to-const or ref-to-const or value, we cannot make the param const
+                            auto fieldDecl = cxxCtorInitializer->getAnyMember();
+                            auto tc = loplugin::TypeCheck(fieldDecl->getType());
+                            if (tc.Pointer() || tc.LvalueReference())
+                                return tc.Pointer().Const() || tc.LvalueReference().Const();
+                            else
+                                return true;
+                        }
+                        else
+                        {
+                            // probably base initialiser, but no simple way to look up the relevant constructor decl
+                            return false;
+                        }
+                    }
+                }
+            }
+            if (auto varDecl = dyn_cast_or_null<VarDecl>(parentsRange.begin()->get<Decl>()))
+            {
+                return isOkForParameter(varDecl->getType());
+            }
+        }
+        parmVarDecl->dump();
+        stmt->dump();
+        report(
+             DiagnosticsEngine::Warning,
+             "no parent?",
+              compat::getBeginLoc(stmt))
+              << stmt->getSourceRange();
+        return false;
+    }
+
+    if (auto unaryOperator = dyn_cast<UnaryOperator>(parent)) {
+        UnaryOperator::Opcode op = unaryOperator->getOpcode();
+        if (op == UO_AddrOf || op == UO_PreInc || op == UO_PostInc
+            || op == UO_PreDec || op == UO_PostDec) {
+            return false;
+        }
+        if (op == UO_Deref) {
+            return checkIfCanBeConst(parent, parmVarDecl);
+        }
+        return true;
+    } else if (auto binaryOp = dyn_cast<BinaryOperator>(parent)) {
+        BinaryOperator::Opcode op = binaryOp->getOpcode();
+        if (binaryOp->getRHS() == stmt && op == BO_Assign) {
+            return isOkForParameter(binaryOp->getLHS()->getType());
+        }
+        if (binaryOp->getRHS() == stmt) {
+            return true;
+        }
+        if (op == BO_Assign || op == BO_PtrMemD || op == BO_PtrMemI || op == BO_MulAssign
+            || op == BO_DivAssign || op == BO_RemAssign || op == BO_AddAssign
+            || op == BO_SubAssign || op == BO_ShlAssign || op == BO_ShrAssign
+            || op == BO_AndAssign || op == BO_XorAssign || op == BO_OrAssign) {
+            return false;
+        }
+        // for pointer arithmetic need to check parent
+        if (binaryOp->getType()->isPointerType()) {
+            return checkIfCanBeConst(parent, parmVarDecl);
+        }
+        return true;
+    } else if (auto constructExpr = dyn_cast<CXXConstructExpr>(parent)) {
+        const CXXConstructorDecl * constructorDecl = constructExpr->getConstructor();
+        for (unsigned i = 0; i < constructExpr->getNumArgs(); ++i) {
+            if (constructExpr->getArg(i) == stmt) {
+                return isOkForParameter(constructorDecl->getParamDecl(i)->getType());
+            }
+        }
+    } else if (auto operatorCallExpr = dyn_cast<CXXOperatorCallExpr>(parent)) {
+        const CXXMethodDecl* calleeMethodDecl = dyn_cast_or_null<CXXMethodDecl>(operatorCallExpr->getDirectCallee());
+        if (calleeMethodDecl) {
+            // unary operator
+            if (calleeMethodDecl->getNumParams() == 0)
+                return calleeMethodDecl->isConst();
+            // Same logic as CXXOperatorCallExpr::isAssignmentOp(), which our supported clang
+            // doesn't have yet.
+            auto Opc = operatorCallExpr->getOperator();
+            if (Opc == OO_Equal || Opc == OO_StarEqual ||
+                Opc == OO_SlashEqual || Opc == OO_PercentEqual ||
+                Opc == OO_PlusEqual || Opc == OO_MinusEqual ||
+                Opc == OO_LessLessEqual || Opc == OO_GreaterGreaterEqual ||
+                Opc == OO_AmpEqual || Opc == OO_CaretEqual ||
+                Opc == OO_PipeEqual)
+            {
+                if (operatorCallExpr->getArg(0) == stmt) // assigning to the param
+                    return false;
+                // not all operator= take a const&
+                return isOkForParameter(calleeMethodDecl->getParamDecl(0)->getType());
+            }
+            if (operatorCallExpr->getOperator() == OO_Subscript && operatorCallExpr->getArg(1) == stmt)
+                return true;
+            if (operatorCallExpr->getOperator() == OO_EqualEqual || operatorCallExpr->getOperator() == OO_ExclaimEqual)
+                return true;
+            // binary operator
+            if (operatorCallExpr->getArg(0) == stmt)
+                return calleeMethodDecl->isConst();
+            unsigned const n = std::min(
+                operatorCallExpr->getNumArgs(),
+                calleeMethodDecl->getNumParams() + 1);
+            for (unsigned i = 1; i < n; ++i)
+                if (operatorCallExpr->getArg(i) == stmt) {
+                    auto qt = calleeMethodDecl->getParamDecl(i - 1)->getType();
+                    return isOkForParameter(qt);
+                }
+        } else {
+            const Expr* callee = operatorCallExpr->getCallee()->IgnoreParenImpCasts();
+            const DeclRefExpr* dr = dyn_cast<DeclRefExpr>(callee);
+            const FunctionDecl* calleeFunctionDecl = nullptr;
+            if (dr) {
+                calleeFunctionDecl = dyn_cast<FunctionDecl>(dr->getDecl());
+            }
+            if (calleeFunctionDecl) {
+                for (unsigned i = 0; i < operatorCallExpr->getNumArgs(); ++i) {
+                    if (operatorCallExpr->getArg(i) == stmt) {
+                        return isOkForParameter(calleeFunctionDecl->getParamDecl(i)->getType());
+                    }
+                }
+            }
+        }
+        return false;
+    } else if (auto callExpr = dyn_cast<CallExpr>(parent)) {
+        QualType functionType = callExpr->getCallee()->getType();
+        if (functionType->isFunctionPointerType()) {
+            functionType = functionType->getPointeeType();
+        }
+        if (const FunctionProtoType* prototype = functionType->getAs<FunctionProtoType>()) {
+            // TODO could do better
+            if (prototype->isVariadic()) {
+                return false;
+            }
+            if (callExpr->getCallee() == stmt) {
+                return true;
+            }
+            for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
+                if (callExpr->getArg(i) == stmt) {
+                    return isOkForParameter(prototype->getParamType(i));
+                }
+            }
+        }
+        const FunctionDecl* calleeFunctionDecl = callExpr->getDirectCallee();
+        if (calleeFunctionDecl)
+        {
+            if (auto memberCallExpr = dyn_cast<CXXMemberCallExpr>(parent)) {
+                const MemberExpr* memberExpr = dyn_cast<MemberExpr>(stmt);
+                if (memberExpr && memberCallExpr->getImplicitObjectArgument() == memberExpr->getBase())
+                {
+                    const CXXMethodDecl* calleeMethodDecl = dyn_cast<CXXMethodDecl>(calleeFunctionDecl);
+                    return calleeMethodDecl->isConst();
+                }
+            }
+            // TODO could do better
+            if (calleeFunctionDecl->isVariadic()) {
+                return false;
+            }
+            if (callExpr->getCallee() == stmt) {
+                return true;
+            }
+            for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
+                if (i >= calleeFunctionDecl->getNumParams()) // can happen in template code
+                    return false;
+                if (callExpr->getArg(i) == stmt) {
+                    return isOkForParameter(calleeFunctionDecl->getParamDecl(i)->getType());
+                }
+            }
+        }
+        return false;
+    } else if (auto callExpr = dyn_cast<ObjCMessageExpr>(parent)) {
+        if (callExpr->getInstanceReceiver() == stmt) {
+            return true;
+        }
+        if (auto const method = callExpr->getMethodDecl()) {
+            // TODO could do better
+            if (method->isVariadic()) {
+                return false;
+            }
+            assert(method->param_size() == callExpr->getNumArgs());
+            for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
+                if (callExpr->getArg(i) == stmt) {
+                    return isOkForParameter(
+                        method->param_begin()[i]->getType());
+                }
+            }
+        }
+    } else if (isa<CXXReinterpretCastExpr>(parent)) {
+        return false;
+    } else if (isa<CXXConstCastExpr>(parent)) {
+        return false;
+    } else if (isa<CastExpr>(parent)) { // all other cast expression subtypes
+        if (auto e = dyn_cast<ExplicitCastExpr>(parent)) {
+            if (loplugin::TypeCheck(e->getTypeAsWritten()).Void()) {
+                if (auto const sub = dyn_cast<DeclRefExpr>(
+                        e->getSubExpr()->IgnoreParenImpCasts()))
+                {
+                    if (sub->getDecl() == parmVarDecl)
+                        return false;
+                }
+            }
+        }
+        return checkIfCanBeConst(parent, parmVarDecl);
+    } else if (isa<MemberExpr>(parent)) {
+        return checkIfCanBeConst(parent, parmVarDecl);
+    } else if (auto arraySubscriptExpr = dyn_cast<ArraySubscriptExpr>(parent)) {
+        if (arraySubscriptExpr->getIdx() == stmt)
+            return true;
+        return checkIfCanBeConst(parent, parmVarDecl);
+    } else if (isa<ParenExpr>(parent)) {
+        return checkIfCanBeConst(parent, parmVarDecl);
+    } else if (isa<DeclStmt>(parent)) {
+        // TODO could do better here, but would require tracking the target(s)
+        //return false;
+    } else if (isa<ReturnStmt>(parent)) {
+        return !isPointerOrReferenceToNonConst(currentFunctionDecl->getReturnType());
+    } else if (isa<InitListExpr>(parent)) {
+        return false;
+    } else if (isa<IfStmt>(parent)) {
+        return true;
+    } else if (isa<WhileStmt>(parent)) {
+        return true;
+    } else if (isa<ForStmt>(parent)) {
+        return true;
+    } else if (isa<CompoundStmt>(parent)) {
+        return true;
+    } else if (isa<SwitchStmt>(parent)) {
+        return true;
+    } else if (isa<DoStmt>(parent)) {
+        return true;
+    } else if (isa<CXXDeleteExpr>(parent)) {
+        return false;
+    } else if (isa<VAArgExpr>(parent)) {
+        return false;
+    } else if (isa<CXXDependentScopeMemberExpr>(parent)) {
+        return false;
+    } else if (isa<MaterializeTemporaryExpr>(parent)) {
+        return checkIfCanBeConst(parent, parmVarDecl);
+    } else if (auto conditionalExpr = dyn_cast<ConditionalOperator>(parent)) {
+        if (conditionalExpr->getCond() == stmt)
+            return true;
+        return checkIfCanBeConst(parent, parmVarDecl);
+    } else if (isa<UnaryExprOrTypeTraitExpr>(parent)) {
+        return false; // ???
+    } else if (auto cxxNewExpr = dyn_cast<CXXNewExpr>(parent)) {
+        for (unsigned i = 0; i < cxxNewExpr->getNumPlacementArgs(); ++i)
+            if (cxxNewExpr->getPlacementArg(i) == stmt)
+                return false;
+        return true; // ???
+    } else if (auto lambdaExpr = dyn_cast<LambdaExpr>(parent)) {
+        for (auto it = lambdaExpr->capture_begin(); it != lambdaExpr->capture_end(); ++it)
+        {
+            if (it->capturesVariable() && it->getCapturedVar() == parmVarDecl)
+                return it->getCaptureKind() != LCK_ByRef;
+        }
+        return false;
+    } else if (isa<CXXTypeidExpr>(parent)) {
+        return true;
+    } else if (isa<ParenListExpr>(parent)) {
+        return false; // could be improved, seen in constructors when calling base class constructor
+    } else if (isa<CXXUnresolvedConstructExpr>(parent)) {
+        return false;
+    } else if (isa<UnresolvedMemberExpr>(parent)) {
+        return false;
+    } else if (isa<PackExpansionExpr>(parent)) {
+        return false;
+    } else if (isa<ExprWithCleanups>(parent)) {
+        return checkIfCanBeConst(parent, parmVarDecl);
+    } else if (isa<CaseStmt>(parent)) {
+        return true;
+    } else if (isa<CXXPseudoDestructorExpr>(parent)) {
+        return false;
+    } else if (isa<CXXDependentScopeMemberExpr>(parent)) {
+        return false;
+    } else if (isa<ObjCIvarRefExpr>(parent)) {
+        return checkIfCanBeConst(parent, parmVarDecl);
+    }
+    parent->dump();
+    parmVarDecl->dump();
+    report(
+         DiagnosticsEngine::Warning,
+         "oh dear, what can the matter be?",
+          compat::getBeginLoc(parent))
+          << parent->getSourceRange();
+    return true;
+}
+
+bool ConstParams::isOkForParameter(const QualType& qt) {
+    if (qt->isIntegralOrEnumerationType())
+        return true;
+    auto const type = loplugin::TypeCheck(qt);
+    if (type.Pointer()) {
+        return bool(type.Pointer().Const());
+    } else if (type.LvalueReference().Const().Pointer()) {
+        // If we have a method that takes (T* t) and it calls std::vector<T*>::push_back
+        // then the type of push_back is T * const &
+        // There is probably a more elegant way to check this, but it will probably require
+        // recalculating types while walking up the AST.
+        return false;
+    } else if (type.LvalueReference()) {
+        return bool(type.LvalueReference().Const());
+    }
+    return false;
+}
+
+bool ConstParams::isPointerOrReferenceToNonConst(const QualType& qt) {
+    auto const type = loplugin::TypeCheck(qt);
+    if (type.Pointer()) {
+        return !bool(type.Pointer().Const());
+    } else if (type.LvalueReference()) {
+        return !bool(type.LvalueReference().Const());
+    }
+    return false;
+}
+
+loplugin::Plugin::Registration< ConstParams > X("constparams", false);
+
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */