Adding upstream version 4:7.4.7.upstream/4%7.4.7upstream

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

1 files changed, 876 insertions, 0 deletions

diff --git a/compilerplugins/clang/vclwidgets.cxx b/compilerplugins/clang/vclwidgets.cxx
new file mode 100644
index 000000000..2f5d6c57a
--- /dev/null
+++ b/compilerplugins/clang/vclwidgets.cxx
@@ -0,0 +1,876 @@
+/* -*- 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 <memory>
+#include <string>
+#include <iostream>
+
+#include "plugin.hxx"
+#include "check.hxx"
+#include "config_clang.h"
+#include "clang/AST/CXXInheritance.h"
+
+// Final goal: Checker for VCL widget references. Makes sure that VCL Window subclasses are properly referenced counted and dispose()'ed.
+//
+// But at the moment it just finds subclasses of Window which are not heap-allocated
+//
+// TODO do I need to check for local and static variables, too ?
+// TODO when we have a dispose() method, verify that the dispose() methods releases all of the Window references
+// TODO when we have a dispose() method, verify that it calls the super-class dispose() method at some point.
+
+namespace {
+
+class VCLWidgets:
+    public loplugin::FilteringPlugin<VCLWidgets>
+{
+public:
+    explicit VCLWidgets(loplugin::InstantiationData const & data): FilteringPlugin(data)
+    {}
+
+    virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool shouldVisitTemplateInstantiations () const { return true; }
+
+    bool VisitVarDecl(const VarDecl *);
+    bool VisitFieldDecl(const FieldDecl *);
+    bool VisitParmVarDecl(const ParmVarDecl *);
+    bool VisitFunctionDecl(const FunctionDecl *);
+    bool VisitCXXDestructorDecl(const CXXDestructorDecl *);
+    bool VisitCXXDeleteExpr(const CXXDeleteExpr *);
+    bool VisitCallExpr(const CallExpr *);
+    bool VisitDeclRefExpr(const DeclRefExpr *);
+    bool VisitCXXConstructExpr(const CXXConstructExpr *);
+    bool VisitBinaryOperator(const BinaryOperator *);
+private:
+    void checkAssignmentForVclPtrToRawConversion(const SourceLocation& sourceLoc, const clang::Type* lhsType, const Expr* rhs);
+    bool isDisposeCallingSuperclassDispose(const CXXMethodDecl* pMethodDecl);
+    bool mbCheckingMemcpy = false;
+};
+
+#define BASE_REF_COUNTED_CLASS "VclReferenceBase"
+
+bool BaseCheckNotWindowSubclass(const CXXRecordDecl *BaseDefinition) {
+    return !loplugin::DeclCheck(BaseDefinition).Class(BASE_REF_COUNTED_CLASS)
+        .GlobalNamespace();
+}
+
+bool isDerivedFromVclReferenceBase(const CXXRecordDecl *decl) {
+    if (!decl)
+        return false;
+    if (loplugin::DeclCheck(decl).Class(BASE_REF_COUNTED_CLASS)
+        .GlobalNamespace())
+    {
+        return true;
+    }
+    if (!decl->hasDefinition()) {
+        return false;
+    }
+    if (// not sure what hasAnyDependentBases() does,
+        // but it avoids classes we don't want, e.g. WeakAggComponentImplHelper1
+        !decl->hasAnyDependentBases() &&
+        !decl->forallBases(BaseCheckNotWindowSubclass)) {
+        return true;
+    }
+    return false;
+}
+
+bool containsVclReferenceBaseSubclass(const clang::Type* pType0);
+
+bool containsVclReferenceBaseSubclass(const QualType& qType) {
+    auto check = loplugin::TypeCheck(qType);
+    if (check.Class("ScopedVclPtr").GlobalNamespace()
+        || check.Class("ScopedVclPtrInstance").GlobalNamespace()
+        || check.Class("VclPtr").GlobalNamespace()
+        || check.Class("VclPtrInstance").GlobalNamespace())
+    {
+        return false;
+    }
+    return containsVclReferenceBaseSubclass(qType.getTypePtr());
+}
+
+bool containsVclReferenceBaseSubclass(const clang::Type* pType0) {
+    if (!pType0)
+        return false;
+    const clang::Type* pType = pType0->getUnqualifiedDesugaredType();
+    if (!pType)
+        return false;
+    const CXXRecordDecl* pRecordDecl = pType->getAsCXXRecordDecl();
+    if (pRecordDecl) {
+        const ClassTemplateSpecializationDecl* pTemplate = dyn_cast<ClassTemplateSpecializationDecl>(pRecordDecl);
+        if (pTemplate) {
+            auto check = loplugin::DeclCheck(pTemplate);
+            if (check.Class("VclStatusListener").GlobalNamespace()) {
+                return false;
+            }
+            bool link = bool(check.Class("Link").GlobalNamespace());
+            for(unsigned i=0; i<pTemplate->getTemplateArgs().size(); ++i) {
+                const TemplateArgument& rArg = pTemplate->getTemplateArgs()[i];
+                if (rArg.getKind() == TemplateArgument::ArgKind::Type &&
+                    containsVclReferenceBaseSubclass(rArg.getAsType()))
+                {
+                    // OK for first template argument of tools/link.hxx Link
+                    // to be a Window-derived pointer:
+                    if (!link || i != 0) {
+                        return true;
+                    }
+                }
+            }
+        }
+    }
+    if (pType->isPointerType()) {
+        QualType pointeeType = pType->getPointeeType();
+        return containsVclReferenceBaseSubclass(pointeeType);
+    } else if (pType->isArrayType()) {
+        const clang::ArrayType* pArrayType = dyn_cast<clang::ArrayType>(pType);
+        QualType elementType = pArrayType->getElementType();
+        return containsVclReferenceBaseSubclass(elementType);
+    } else {
+        return isDerivedFromVclReferenceBase(pRecordDecl);
+    }
+}
+
+bool VCLWidgets::VisitCXXDestructorDecl(const CXXDestructorDecl* pCXXDestructorDecl)
+{
+    if (ignoreLocation(pCXXDestructorDecl)) {
+        return true;
+    }
+    if (!pCXXDestructorDecl->isThisDeclarationADefinition()) {
+        return true;
+    }
+    const CXXRecordDecl * pRecordDecl = pCXXDestructorDecl->getParent();
+    // ignore
+    if (loplugin::DeclCheck(pRecordDecl).Class(BASE_REF_COUNTED_CLASS)
+        .GlobalNamespace())
+    {
+        return true;
+    }
+    // check if this class is derived from VclReferenceBase
+    if (!isDerivedFromVclReferenceBase(pRecordDecl)) {
+        return true;
+    }
+    // check if we have any VclPtr<> fields
+    bool bFoundVclPtrField = false;
+    for(auto fieldDecl = pRecordDecl->field_begin();
+        fieldDecl != pRecordDecl->field_end(); ++fieldDecl)
+    {
+        const RecordType *pFieldRecordType = fieldDecl->getType()->getAs<RecordType>();
+        if (pFieldRecordType) {
+            if (loplugin::DeclCheck(pFieldRecordType->getDecl())
+                .Class("VclPtr").GlobalNamespace())
+            {
+               bFoundVclPtrField = true;
+               break;
+            }
+       }
+    }
+    // check if there is a dispose() method
+    bool bFoundDispose = false;
+    for(auto methodDecl = pRecordDecl->method_begin();
+        methodDecl != pRecordDecl->method_end(); ++methodDecl)
+    {
+        if (methodDecl->isInstance() && methodDecl->param_size()==0
+            && loplugin::DeclCheck(*methodDecl).Function("dispose"))
+        {
+           bFoundDispose = true;
+           break;
+        }
+    }
+    const CompoundStmt *pCompoundStatement = dyn_cast_or_null<CompoundStmt>(pCXXDestructorDecl->getBody());
+    // having an empty body and no dispose() method is fine
+    if (!bFoundVclPtrField && !bFoundDispose && (!pCompoundStatement || pCompoundStatement->size() == 0)) {
+        return true;
+    }
+    if (bFoundVclPtrField && (!pCompoundStatement || pCompoundStatement->size() == 0)) {
+        report(
+            DiagnosticsEngine::Warning,
+            BASE_REF_COUNTED_CLASS " subclass with VclPtr field must call disposeOnce() from its destructor",
+            pCXXDestructorDecl->getBeginLoc())
+          << pCXXDestructorDecl->getSourceRange();
+        return true;
+    }
+    // Check that the destructor for a BASE_REF_COUNTED_CLASS subclass either
+    // only calls disposeOnce() or, if !bFoundVclPtrField, does nothing at all:
+    bool bOk = false;
+    if (pCompoundStatement) {
+        bool bFoundDisposeOnce = false;
+        int nNumExtraStatements = 0;
+        for (auto i = pCompoundStatement->body_begin();
+             i != pCompoundStatement->body_end(); ++i)
+        {
+            //TODO: The below erroneously also skips past entire statements like
+            //
+            //  assert(true), ...;
+            //
+            auto skip = false;
+            for (auto loc = (*i)->getBeginLoc();
+                 compiler.getSourceManager().isMacroBodyExpansion(loc);
+                 loc = compiler.getSourceManager().getImmediateMacroCallerLoc(
+                     loc))
+            {
+                auto const name = Lexer::getImmediateMacroName(
+                    loc, compiler.getSourceManager(), compiler.getLangOpts());
+                if (name == "SAL_DEBUG" || name == "assert") {
+                    skip = true;
+                    break;
+                }
+            }
+            if (skip) {
+                continue;
+            }
+            if (auto const pCallExpr = dyn_cast<CXXMemberCallExpr>(*i)) {
+                if( const FunctionDecl* func = pCallExpr->getDirectCallee()) {
+                    if( func->getNumParams() == 0 && func->getIdentifier() != NULL
+                        && ( func->getName() == "disposeOnce" )) {
+                        bFoundDisposeOnce = true;
+                        continue;
+                    }
+                }
+            }
+            nNumExtraStatements++;
+        }
+        bOk = (bFoundDisposeOnce || !bFoundVclPtrField)
+            && nNumExtraStatements == 0;
+    }
+    if (!bOk) {
+        SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(
+                              pCXXDestructorDecl->getBeginLoc());
+        StringRef filename = getFilenameOfLocation(spellingLocation);
+        if (   !(loplugin::isSamePathname(filename, SRCDIR "/vcl/source/window/window.cxx"))
+            && !(loplugin::isSamePathname(filename, SRCDIR "/vcl/source/gdi/virdev.cxx"))
+            && !(loplugin::isSamePathname(filename, SRCDIR "/vcl/qa/cppunit/lifecycle.cxx"))
+            && !(loplugin::isSamePathname(filename, SRCDIR "/sfx2/source/dialog/tabdlg.cxx")) )
+        {
+            report(
+                DiagnosticsEngine::Warning,
+                BASE_REF_COUNTED_CLASS " subclass should have nothing in its destructor but a call to disposeOnce()",
+                pCXXDestructorDecl->getBeginLoc())
+              << pCXXDestructorDecl->getSourceRange();
+        }
+    }
+    return true;
+}
+
+bool VCLWidgets::VisitBinaryOperator(const BinaryOperator * binaryOperator)
+{
+    if (ignoreLocation(binaryOperator)) {
+        return true;
+    }
+    if ( !binaryOperator->isAssignmentOp() ) {
+        return true;
+    }
+    SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(
+                          binaryOperator->getBeginLoc());
+    checkAssignmentForVclPtrToRawConversion(spellingLocation, binaryOperator->getLHS()->getType().getTypePtr(), binaryOperator->getRHS());
+    return true;
+}
+
+// Look for places where we are accidentally assigning a returned-by-value VclPtr<T> to a T*, which generally
+// ends up in a use-after-free.
+void VCLWidgets::checkAssignmentForVclPtrToRawConversion(const SourceLocation& spellingLocation, const clang::Type* lhsType, const Expr* rhs)
+{
+    if (!lhsType || !isa<clang::PointerType>(lhsType)) {
+        return;
+    }
+    if (!rhs) {
+        return;
+    }
+    StringRef filename = getFilenameOfLocation(spellingLocation);
+    if (loplugin::isSamePathname(filename, SRCDIR "/include/rtl/ref.hxx")) {
+        return;
+    }
+    const CXXRecordDecl* pointeeClass = lhsType->getPointeeType()->getAsCXXRecordDecl();
+    if (!isDerivedFromVclReferenceBase(pointeeClass)) {
+        return;
+    }
+
+    // if we have T* on the LHS and VclPtr<T> on the RHS, we expect to see either
+    // an ImplicitCastExpr
+    // or an ExprWithCleanups and then an ImplicitCastExpr
+    if (auto implicitCastExpr = dyn_cast<ImplicitCastExpr>(rhs)) {
+        if (implicitCastExpr->getCastKind() != CK_UserDefinedConversion) {
+            return;
+        }
+        rhs = rhs->IgnoreCasts();
+    } else if (auto exprWithCleanups = dyn_cast<ExprWithCleanups>(rhs)) {
+        if (auto implicitCastExpr = dyn_cast<ImplicitCastExpr>(exprWithCleanups->getSubExpr())) {
+            if (implicitCastExpr->getCastKind() != CK_UserDefinedConversion) {
+                return;
+            }
+            rhs = exprWithCleanups->IgnoreCasts();
+        } else {
+            return;
+        }
+    } else {
+        return;
+    }
+    if (isa<CXXNullPtrLiteralExpr>(rhs)) {
+        return;
+    }
+    if (isa<CXXThisExpr>(rhs)) {
+        return;
+    }
+
+    // ignore assignments from a member field to a local variable, to avoid unnecessary refcounting traffic
+    if (auto callExpr = dyn_cast<CXXMemberCallExpr>(rhs)) {
+        if (auto calleeMemberExpr = dyn_cast<MemberExpr>(callExpr->getCallee())) {
+            if ((calleeMemberExpr = dyn_cast<MemberExpr>(calleeMemberExpr->getBase()->IgnoreImpCasts()))) {
+                if (isa<FieldDecl>(calleeMemberExpr->getMemberDecl())) {
+                    return;
+                }
+            }
+        }
+    }
+
+    // ignore assignments from a local variable to a local variable, to avoid unnecessary refcounting traffic
+    if (auto callExpr = dyn_cast<CXXMemberCallExpr>(rhs)) {
+        if (auto calleeMemberExpr = dyn_cast<MemberExpr>(callExpr->getCallee())) {
+            if (auto declRefExpr = dyn_cast<DeclRefExpr>(calleeMemberExpr->getBase()->IgnoreImpCasts())) {
+                if (isa<VarDecl>(declRefExpr->getDecl())) {
+                    return;
+                }
+            }
+        }
+    }
+    if (auto declRefExpr = dyn_cast<DeclRefExpr>(rhs->IgnoreImpCasts())) {
+        if (isa<VarDecl>(declRefExpr->getDecl())) {
+             return;
+        }
+    }
+
+    report(
+        DiagnosticsEngine::Warning,
+        "assigning a returned-by-value VclPtr<T> to a T* variable is dodgy, should be assigned to a VclPtr. If you know that the RHS does not return a newly created T, then add a '.get()' to the RHS",
+         rhs->getSourceRange().getBegin())
+        << rhs->getSourceRange();
+}
+
+bool VCLWidgets::VisitVarDecl(const VarDecl * pVarDecl) {
+    if (ignoreLocation(pVarDecl)) {
+        return true;
+    }
+    if (isa<ParmVarDecl>(pVarDecl)) {
+        return true;
+    }
+    SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(
+                          pVarDecl->getBeginLoc());
+    if (pVarDecl->getInit()) {
+        checkAssignmentForVclPtrToRawConversion(spellingLocation, pVarDecl->getType().getTypePtr(), pVarDecl->getInit());
+    }
+    StringRef aFileName = getFilenameOfLocation(spellingLocation);
+    if (loplugin::isSamePathname(aFileName, SRCDIR "/include/vcl/vclptr.hxx"))
+        return true;
+    if (loplugin::isSamePathname(aFileName, SRCDIR "/vcl/source/window/layout.cxx"))
+        return true;
+    // allowlist the valid things that can contain pointers.
+    // It is containing stuff like std::unique_ptr we get worried
+    if (pVarDecl->getType()->isArrayType()) {
+        return true;
+    }
+    auto tc = loplugin::TypeCheck(pVarDecl->getType());
+    if (tc.Pointer()
+        || tc.Class("map").StdNamespace()
+        || tc.Class("multimap").StdNamespace()
+        || tc.Class("vector").StdNamespace()
+        || tc.Class("list").StdNamespace()
+        || tc.Class("mem_fun1_t").StdNamespace()
+          // registration template thing, doesn't actually allocate anything we need to care about
+        || tc.Class("OMultiInstanceAutoRegistration").Namespace("compmodule").GlobalNamespace())
+    {
+        return true;
+    }
+    // Apparently I should be doing some kind of lookup for a partial specialisations of std::iterator_traits<T> to see if an
+    // object is an iterator, but that sounds like too much work
+    auto t = pVarDecl->getType().getDesugaredType(compiler.getASTContext());
+    std::string s = t.getAsString();
+    if (s.find("iterator") != std::string::npos
+        || loplugin::TypeCheck(t).Class("__wrap_iter").StdNamespace())
+    {
+        return true;
+    }
+    // std::pair seems to show up in whacky ways in clang's AST. Sometimes it's a class, sometimes it's a typedef, and sometimes
+    // it's an ElaboratedType (whatever that is)
+    if (s.find("pair") != std::string::npos) {
+        return true;
+    }
+
+    if (containsVclReferenceBaseSubclass(pVarDecl->getType())) {
+        report(
+            DiagnosticsEngine::Warning,
+            BASE_REF_COUNTED_CLASS " subclass %0 should be wrapped in VclPtr",
+            pVarDecl->getLocation())
+            << pVarDecl->getType() << pVarDecl->getSourceRange();
+        return true;
+    }
+    return true;
+}
+
+bool VCLWidgets::VisitFieldDecl(const FieldDecl * fieldDecl) {
+    if (ignoreLocation(fieldDecl)) {
+        return true;
+    }
+    StringRef aFileName = getFilenameOfLocation(
+        compiler.getSourceManager().getSpellingLoc(fieldDecl->getBeginLoc()));
+    if (loplugin::isSamePathname(aFileName, SRCDIR "/include/vcl/vclptr.hxx"))
+        return true;
+    if (loplugin::isSamePathname(aFileName, SRCDIR "/include/rtl/ref.hxx"))
+        return true;
+    if (loplugin::isSamePathname(aFileName, SRCDIR "/include/o3tl/enumarray.hxx"))
+        return true;
+    if (loplugin::isSamePathname(aFileName, SRCDIR "/vcl/source/window/layout.cxx"))
+        return true;
+    if (fieldDecl->isBitField()) {
+        return true;
+    }
+    const CXXRecordDecl *pParentRecordDecl = isa<RecordDecl>(fieldDecl->getDeclContext()) ? dyn_cast<CXXRecordDecl>(fieldDecl->getParent()) : nullptr;
+    if (loplugin::DeclCheck(pParentRecordDecl).Class("VclPtr")
+        .GlobalNamespace())
+    {
+        return true;
+    }
+    if (containsVclReferenceBaseSubclass(fieldDecl->getType())) {
+        // have to ignore this for now, nasty reverse dependency from tools->vcl
+        auto check = loplugin::DeclCheck(pParentRecordDecl);
+        if (!(check.Struct("ImplErrorContext").GlobalNamespace()
+              || check.Class("ScHFEditPage").GlobalNamespace()))
+        {
+            report(
+                DiagnosticsEngine::Warning,
+                BASE_REF_COUNTED_CLASS " subclass %0 declared as a pointer member, should be wrapped in VclPtr",
+                fieldDecl->getLocation())
+                << fieldDecl->getType() << fieldDecl->getSourceRange();
+            if (auto parent = dyn_cast<ClassTemplateSpecializationDecl>(fieldDecl->getParent())) {
+                report(
+                    DiagnosticsEngine::Note,
+                    "template field here",
+                    parent->getPointOfInstantiation());
+            }
+            return true;
+        }
+    }
+    const RecordType *recordType = fieldDecl->getType()->getAs<RecordType>();
+    if (recordType == nullptr) {
+        return true;
+    }
+    const CXXRecordDecl *recordDecl = dyn_cast<CXXRecordDecl>(recordType->getDecl());
+    if (recordDecl == nullptr) {
+        return true;
+    }
+
+    // check if this field is derived fromVclReferenceBase
+    if (isDerivedFromVclReferenceBase(recordDecl)) {
+        report(
+            DiagnosticsEngine::Warning,
+            BASE_REF_COUNTED_CLASS " subclass allocated as a class member, should be allocated via VclPtr",
+            fieldDecl->getLocation())
+          << fieldDecl->getSourceRange();
+    }
+
+    // If this field is a VclPtr field, then the class MUST have a dispose method
+    if (pParentRecordDecl && isDerivedFromVclReferenceBase(pParentRecordDecl)
+        && loplugin::DeclCheck(recordDecl).Class("VclPtr").GlobalNamespace())
+    {
+        bool bFoundDispose = false;
+        for(auto methodDecl = pParentRecordDecl->method_begin();
+            methodDecl != pParentRecordDecl->method_end(); ++methodDecl)
+        {
+            if (methodDecl->isInstance() && methodDecl->param_size()==0
+                && loplugin::DeclCheck(*methodDecl).Function("dispose"))
+            {
+               bFoundDispose = true;
+               break;
+            }
+        }
+        if (!bFoundDispose) {
+            report(
+                DiagnosticsEngine::Warning,
+                BASE_REF_COUNTED_CLASS " subclass with a VclPtr field MUST override dispose() (and call its superclass dispose() as the last thing it does)",
+                fieldDecl->getLocation())
+              << fieldDecl->getSourceRange();
+        }
+        if (!pParentRecordDecl->hasUserDeclaredDestructor()) {
+            report(
+                DiagnosticsEngine::Warning,
+                BASE_REF_COUNTED_CLASS " subclass with a VclPtr field MUST have a user-provided destructor (that calls disposeOnce())",
+                fieldDecl->getLocation())
+              << fieldDecl->getSourceRange();
+        }
+    }
+
+    return true;
+}
+
+bool VCLWidgets::VisitParmVarDecl(ParmVarDecl const * pvDecl)
+{
+    if (ignoreLocation(pvDecl)) {
+        return true;
+    }
+    // ignore the stuff in the VclPtr template class
+    const CXXMethodDecl *pMethodDecl = dyn_cast<CXXMethodDecl>(pvDecl->getDeclContext());
+    if (loplugin::DeclCheck(pMethodDecl).MemberFunction().Class("VclPtr")
+        .GlobalNamespace())
+    {
+        return true;
+    }
+    // we exclude this method in VclBuilder because it's so useful to have it like this
+    auto check = loplugin::DeclCheck(pMethodDecl).Function("get");
+    if (check.Class("VclBuilder").GlobalNamespace()
+        || check.Class("VclBuilderContainer").GlobalNamespace())
+    {
+        return true;
+    }
+    return true;
+}
+
+
+static void findDisposeAndClearStatements(std::set<const FieldDecl*>& aVclPtrFields, const Stmt *pStmt)
+{
+    if (!pStmt)
+        return;
+    if (isa<CompoundStmt>(pStmt)) {
+        const CompoundStmt *pCompoundStatement = dyn_cast<CompoundStmt>(pStmt);
+        for (auto i = pCompoundStatement->body_begin();
+             i != pCompoundStatement->body_end(); ++i)
+        {
+            findDisposeAndClearStatements(aVclPtrFields, *i);
+        }
+        return;
+    }
+    if (isa<ForStmt>(pStmt)) {
+        findDisposeAndClearStatements(aVclPtrFields, dyn_cast<ForStmt>(pStmt)->getBody());
+        return;
+    }
+    if (isa<IfStmt>(pStmt)) {
+        findDisposeAndClearStatements(aVclPtrFields, dyn_cast<IfStmt>(pStmt)->getThen());
+        findDisposeAndClearStatements(aVclPtrFields, dyn_cast<IfStmt>(pStmt)->getElse());
+        return;
+    }
+    if (!isa<CallExpr>(pStmt)) return;
+    const CallExpr *pCallExpr = dyn_cast<CallExpr>(pStmt);
+
+    if (!pCallExpr->getDirectCallee()) return;
+    if (!isa<CXXMethodDecl>(pCallExpr->getDirectCallee())) return;
+    auto check = loplugin::DeclCheck(
+        dyn_cast<CXXMethodDecl>(pCallExpr->getDirectCallee()));
+    if (!(check.Function("disposeAndClear") || check.Function("clear")))
+            return;
+
+    if (!pCallExpr->getCallee()) return;
+
+    if (!isa<MemberExpr>(pCallExpr->getCallee())) return;
+    const MemberExpr *pCalleeMemberExpr = dyn_cast<MemberExpr>(pCallExpr->getCallee());
+
+    if (!pCalleeMemberExpr->getBase()) return;
+    const MemberExpr *pCalleeMemberExprBase = dyn_cast<MemberExpr>(pCalleeMemberExpr->getBase()->IgnoreImpCasts());
+    if (pCalleeMemberExprBase == nullptr) return;
+
+    const FieldDecl* xxx = dyn_cast_or_null<FieldDecl>(pCalleeMemberExprBase->getMemberDecl());
+    if (xxx)
+        aVclPtrFields.erase(xxx);
+}
+
+
+bool VCLWidgets::VisitFunctionDecl( const FunctionDecl* functionDecl )
+{
+    if (ignoreLocation(functionDecl)) {
+        return true;
+    }
+    // ignore the stuff in the VclPtr template class
+    if (loplugin::DeclCheck(functionDecl).MemberFunction().Class("VclPtr")
+        .GlobalNamespace())
+    {
+        return true;
+    }
+    // ignore the BASE_REF_COUNTED_CLASS::dispose() method
+    if (loplugin::DeclCheck(functionDecl).Function("dispose")
+        .Class(BASE_REF_COUNTED_CLASS).GlobalNamespace())
+    {
+        return true;
+    }
+    const CXXMethodDecl *pMethodDecl = dyn_cast<CXXMethodDecl>(functionDecl);
+    if (functionDecl->hasBody() && pMethodDecl && isDerivedFromVclReferenceBase(pMethodDecl->getParent())) {
+        // check the last thing that the dispose() method does, is to call into the superclass dispose method
+        if (loplugin::DeclCheck(functionDecl).Function("dispose")) {
+            if (!isDisposeCallingSuperclassDispose(pMethodDecl)) {
+                // We specifically have to clear a member variable AFTER calling super::dispose() here, unfortunately
+                if (!loplugin::DeclCheck(pMethodDecl->getParent()).Class("WindowOutputDevice"))
+                    report(
+                        DiagnosticsEngine::Warning,
+                        BASE_REF_COUNTED_CLASS " subclass dispose() function MUST call dispose() of its superclass as the last thing it does",
+                        functionDecl->getBeginLoc())
+                      << functionDecl->getSourceRange();
+           }
+        }
+    }
+
+    // check dispose method to make sure we are actually disposing all of the VclPtr fields
+    // FIXME this is not exhaustive. We should enable shouldVisitTemplateInstantiations and look deeper inside type declarations
+    if (pMethodDecl && pMethodDecl->isInstance() && pMethodDecl->getBody()
+        && pMethodDecl->param_size()==0
+        && loplugin::DeclCheck(functionDecl).Function("dispose")
+        && isDerivedFromVclReferenceBase(pMethodDecl->getParent()) )
+    {
+        auto check = loplugin::DeclCheck(functionDecl).MemberFunction();
+        if (check.Class("VirtualDevice").GlobalNamespace()
+            || check.Class("Breadcrumb").GlobalNamespace())
+        {
+            return true;
+        }
+
+        std::set<const FieldDecl*> aVclPtrFields;
+        for (auto i = pMethodDecl->getParent()->field_begin();
+             i != pMethodDecl->getParent()->field_end(); ++i)
+        {
+            auto const type = loplugin::TypeCheck((*i)->getType());
+            if (type.Class("VclPtr").GlobalNamespace()) {
+               aVclPtrFields.insert(*i);
+            } else if (type.Class("vector").StdNamespace()
+                       || type.Class("map").StdNamespace()
+                       || type.Class("list").StdNamespace()
+                       || type.Class("set").StdNamespace())
+            {
+                const RecordType* recordType = dyn_cast_or_null<RecordType>((*i)->getType()->getUnqualifiedDesugaredType());
+                if (recordType) {
+                    auto d = dyn_cast<ClassTemplateSpecializationDecl>(recordType->getDecl());
+                    if (d && d->getTemplateArgs().size()>0) {
+                        auto const type = loplugin::TypeCheck(d->getTemplateArgs()[0].getAsType());
+                        if (type.Class("VclPtr").GlobalNamespace()) {
+                            aVclPtrFields.insert(*i);
+                        }
+                    }
+                }
+            }
+        }
+        if (!aVclPtrFields.empty()) {
+            findDisposeAndClearStatements( aVclPtrFields, pMethodDecl->getBody() );
+            if (!aVclPtrFields.empty()) {
+                //pMethodDecl->dump();
+                std::string aMessage = BASE_REF_COUNTED_CLASS " subclass dispose() method does not call disposeAndClear() or clear() on the following field(s): ";
+                for(auto s : aVclPtrFields)
+                    aMessage += ", " + s->getNameAsString();
+                report(
+                    DiagnosticsEngine::Warning,
+                    aMessage,
+                    functionDecl->getBeginLoc())
+                  << functionDecl->getSourceRange();
+           }
+       }
+    }
+
+    return true;
+}
+
+bool VCLWidgets::VisitCXXDeleteExpr(const CXXDeleteExpr *pCXXDeleteExpr)
+{
+    if (ignoreLocation(pCXXDeleteExpr)) {
+        return true;
+    }
+    const CXXRecordDecl *pPointee = pCXXDeleteExpr->getArgument()->getType()->getPointeeCXXRecordDecl();
+    if (pPointee && isDerivedFromVclReferenceBase(pPointee)) {
+        SourceLocation spellingLocation = compiler.getSourceManager().getSpellingLoc(
+                              pCXXDeleteExpr->getBeginLoc());
+        StringRef filename = getFilenameOfLocation(spellingLocation);
+        if ( !(loplugin::isSamePathname(filename, SRCDIR "/include/vcl/vclreferencebase.hxx")))
+        {
+            report(
+                DiagnosticsEngine::Warning,
+                "calling delete on instance of " BASE_REF_COUNTED_CLASS " subclass, must rather call disposeAndClear()",
+                pCXXDeleteExpr->getBeginLoc())
+              << pCXXDeleteExpr->getSourceRange();
+        }
+    }
+    const ImplicitCastExpr* pImplicitCastExpr = dyn_cast<ImplicitCastExpr>(pCXXDeleteExpr->getArgument());
+    if (!pImplicitCastExpr) {
+        return true;
+    }
+    if (pImplicitCastExpr->getCastKind() != CK_UserDefinedConversion) {
+        return true;
+    }
+    if (!loplugin::TypeCheck(pImplicitCastExpr->getSubExprAsWritten()->getType()).Class("VclPtr")
+        .GlobalNamespace())
+    {
+        return true;
+    }
+    report(
+        DiagnosticsEngine::Warning,
+        "calling delete on instance of VclPtr, must rather call disposeAndClear()",
+        pCXXDeleteExpr->getBeginLoc())
+     << pCXXDeleteExpr->getSourceRange();
+    return true;
+}
+
+
+/**
+The AST looks like:
+`-CXXMemberCallExpr 0xb06d8b0 'void'
+  `-MemberExpr 0xb06d868 '<bound member function type>' ->dispose 0x9d34880
+    `-ImplicitCastExpr 0xb06d8d8 'class SfxTabPage *' <UncheckedDerivedToBase (SfxTabPage)>
+      `-CXXThisExpr 0xb06d850 'class SfxAcceleratorConfigPage *' this
+
+*/
+bool VCLWidgets::isDisposeCallingSuperclassDispose(const CXXMethodDecl* pMethodDecl)
+{
+    const CompoundStmt *pCompoundStatement = dyn_cast<CompoundStmt>(pMethodDecl->getBody());
+    if (!pCompoundStatement) return false;
+    if (pCompoundStatement->size() == 0) return false;
+    // find the last statement
+    const CXXMemberCallExpr *pCallExpr = dyn_cast<CXXMemberCallExpr>(*pCompoundStatement->body_rbegin());
+    if (!pCallExpr) return false;
+    const MemberExpr *pMemberExpr = dyn_cast<MemberExpr>(pCallExpr->getCallee());
+    if (!pMemberExpr) return false;
+    if (!loplugin::DeclCheck(pMemberExpr->getMemberDecl()).Function("dispose")) return false;
+    const CXXMethodDecl *pDirectCallee = dyn_cast<CXXMethodDecl>(pCallExpr->getDirectCallee());
+    if (!pDirectCallee) return false;
+/* Not working yet. Partially because sometimes the superclass does not a dispose() method, so it gets passed up the chain.
+   Need complex checking for that case.
+    if (pDirectCallee->getParent()->getTypeForDecl() != (*pMethodDecl->getParent()->bases_begin()).getType().getTypePtr()) {
+        report(
+            DiagnosticsEngine::Warning,
+            "dispose() method calling wrong baseclass, calling " + pDirectCallee->getParent()->getQualifiedNameAsString() +
+            " should be calling " + (*pMethodDecl->getParent()->bases_begin()).getType().getAsString(),
+            pCallExpr->getLocStart())
+          << pCallExpr->getSourceRange();
+        return false;
+    }*/
+    return true;
+}
+
+bool containsVclPtr(const clang::Type* pType0);
+
+bool containsVclPtr(const QualType& qType) {
+    auto check = loplugin::TypeCheck(qType);
+    if (check.Class("ScopedVclPtr").GlobalNamespace()
+        || check.Class("ScopedVclPtrInstance").GlobalNamespace()
+        || check.Class("VclPtr").GlobalNamespace()
+        || check.Class("VclPtrInstance").GlobalNamespace())
+    {
+        return true;
+    }
+    return containsVclPtr(qType.getTypePtr());
+}
+
+bool containsVclPtr(const clang::Type* pType0) {
+    if (!pType0)
+        return false;
+    const clang::Type* pType = pType0->getUnqualifiedDesugaredType();
+    if (!pType)
+        return false;
+    if (pType->isPointerType()) {
+        return false;
+    } else if (pType->isArrayType()) {
+        const clang::ArrayType* pArrayType = dyn_cast<clang::ArrayType>(pType);
+        QualType elementType = pArrayType->getElementType();
+        return containsVclPtr(elementType);
+    } else {
+        const CXXRecordDecl* pRecordDecl = pType->getAsCXXRecordDecl();
+        if (pRecordDecl)
+        {
+            auto check = loplugin::DeclCheck(pRecordDecl);
+            if (check.Class("ScopedVclPtr").GlobalNamespace()
+                || check.Class("ScopedVclPtrInstance").GlobalNamespace()
+                || check.Class("VclPtr").GlobalNamespace()
+                || check.Class("VclPtrInstance").GlobalNamespace())
+            {
+                return true;
+            }
+            for(auto fieldDecl = pRecordDecl->field_begin();
+                fieldDecl != pRecordDecl->field_end(); ++fieldDecl)
+            {
+                const RecordType *pFieldRecordType = fieldDecl->getType()->getAs<RecordType>();
+                if (pFieldRecordType && containsVclPtr(pFieldRecordType)) {
+                    return true;
+                }
+            }
+            for(auto baseSpecifier = pRecordDecl->bases_begin();
+                baseSpecifier != pRecordDecl->bases_end(); ++baseSpecifier)
+            {
+                const RecordType *pFieldRecordType = baseSpecifier->getType()->getAs<RecordType>();
+                if (pFieldRecordType && containsVclPtr(pFieldRecordType)) {
+                    return true;
+                }
+            }
+        }
+    }
+    return false;
+}
+
+bool VCLWidgets::VisitCallExpr(const CallExpr* pCallExpr)
+{
+    if (ignoreLocation(pCallExpr)) {
+        return true;
+    }
+    FunctionDecl const * fdecl = pCallExpr->getDirectCallee();
+    if (fdecl == nullptr) {
+        return true;
+    }
+    std::string qname { fdecl->getQualifiedNameAsString() };
+    if (qname.find("memcpy") == std::string::npos
+         && qname.find("bcopy") == std::string::npos
+         && qname.find("memmove") == std::string::npos
+         && qname.find("rtl_copy") == std::string::npos) {
+        return true;
+    }
+    mbCheckingMemcpy = true;
+    Stmt * pStmt = const_cast<Stmt*>(static_cast<const Stmt*>(pCallExpr->getArg(0)));
+    TraverseStmt(pStmt);
+    mbCheckingMemcpy = false;
+    return true;
+}
+
+bool VCLWidgets::VisitDeclRefExpr(const DeclRefExpr* pDeclRefExpr)
+{
+    if (!mbCheckingMemcpy) {
+        return true;
+    }
+    if (ignoreLocation(pDeclRefExpr)) {
+        return true;
+    }
+    QualType pType = pDeclRefExpr->getDecl()->getType();
+    if (pType->isPointerType()) {
+        pType = pType->getPointeeType();
+    }
+    if (!containsVclPtr(pType)) {
+        return true;
+    }
+    report(
+        DiagnosticsEngine::Warning,
+        "Calling memcpy on a type which contains a VclPtr",
+        pDeclRefExpr->getExprLoc());
+    return true;
+}
+
+bool VCLWidgets::VisitCXXConstructExpr( const CXXConstructExpr* constructExpr )
+{
+    if (ignoreLocation(constructExpr)) {
+        return true;
+    }
+    if (constructExpr->getConstructionKind() != CXXConstructExpr::CK_Complete) {
+        return true;
+    }
+    const CXXConstructorDecl* pConstructorDecl = constructExpr->getConstructor();
+    const CXXRecordDecl* recordDecl = pConstructorDecl->getParent();
+    if (isDerivedFromVclReferenceBase(recordDecl)) {
+        StringRef aFileName = getFilenameOfLocation(
+            compiler.getSourceManager().getSpellingLoc(constructExpr->getBeginLoc()));
+        if (!loplugin::isSamePathname(aFileName, SRCDIR "/include/vcl/vclptr.hxx")) {
+            report(
+                DiagnosticsEngine::Warning,
+                "Calling constructor of a VclReferenceBase-derived type directly; all such creation should go via VclPtr<>::Create",
+                constructExpr->getExprLoc());
+        }
+    }
+    return true;
+}
+
+loplugin::Plugin::Registration< VCLWidgets > vclwidgets("vclwidgets");
+
+}
+
+// Cannot be shared, uses TraverseStmt().
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */