tdf#89522 PERF FILEOPEN xlsx, part 1

Inherit from tools::WeakBase non-virtually, so that we can use a
static_cast in tools::WeakReference::get instead of a dynamic_cast.

This takes the file-open time from 1m21 to 40s for me.

Add a clang plugin to make sure we don't accidentally end up inheriting
from tools::WeakBase more than once.

Change-Id: I9c7c36403333f99094e1f9d8cce2ecd9200377f9
Reviewed-on: https://gerrit.libreoffice.org/71231
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>

2 files changed, 144 insertions, 0 deletions

diff --git a/compilerplugins/clang/test/weakbase.cxx b/compilerplugins/clang/test/weakbase.cxx
new file mode 100644
index 000000000000..a59a5372891e
--- /dev/null
+++ b/compilerplugins/clang/test/weakbase.cxx
@@ -0,0 +1,34 @@
+/* -*- 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/.
+ */
+
+namespace tools
+{
+struct WeakBase
+{
+    virtual ~WeakBase();
+};
+}
+
+struct Foo1 : public tools::WeakBase
+{
+    virtual ~Foo1();
+};
+
+struct Foo2 : public tools::WeakBase
+{
+    virtual ~Foo2();
+};
+
+// expected-error@+1 {{multiple copies of WeakBase, through inheritance paths Bar->Foo1->WeakBase, Bar->Foo2->WeakBase [loplugin:weakbase]}}
+struct Bar : public Foo1, public Foo2
+{
+    virtual ~Bar();
+};
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/weakbase.cxx b/compilerplugins/clang/weakbase.cxx
new file mode 100644
index 000000000000..fbd72955c0ba
--- /dev/null
+++ b/compilerplugins/clang/weakbase.cxx
@@ -0,0 +1,110 @@
+/* -*- 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 <string>
+#include <iostream>
+#include <map>
+#include <set>
+
+#include "plugin.hxx"
+#include "clang/AST/CXXInheritance.h"
+
+/**
+ * Check for multiple copies of WeakBase in base classes
+ */
+namespace
+{
+class WeakBase : public loplugin::FilteringPlugin<WeakBase>
+{
+public:
+    explicit WeakBase(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    virtual void run() override { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
+
+    bool VisitCXXRecordDecl(CXXRecordDecl const*);
+};
+
+bool WeakBase::VisitCXXRecordDecl(CXXRecordDecl const* recordDecl)
+{
+    if (ignoreLocation(recordDecl))
+    {
+        return true;
+    }
+    //    StringRef aFileName = getFileNameOfSpellingLoc(
+    //        compiler.getSourceManager().getSpellingLoc(compat::getBeginLoc(fieldDecl)));
+
+    //    if (loplugin::hasPathnamePrefix(aFileName, SRCDIR "/chart2/source/"))
+    //        return true;
+    //    if (loplugin::isSamePathname(aFileName, SRCDIR "/include/sfx2/recentdocsview.hxx"))
+    //        return true;
+    //    if (loplugin::isSamePathname(aFileName, SRCDIR "/include/sfx2/templatelocalview.hxx"))
+    //        return true;
+    //    if (loplugin::isSamePathname(aFileName, SRCDIR "/store/source/stortree.hxx")
+    //        || loplugin::isSamePathname(aFileName, SRCDIR "/store/source/stordata.hxx"))
+    //        return true;
+    //    if (loplugin::isSamePathname(aFileName, SRCDIR "/sw/source/uibase/inc/dbtree.hxx"))
+    //        return true;
+
+    recordDecl = recordDecl->getCanonicalDecl();
+    if (!recordDecl->hasDefinition())
+        return true;
+
+    int noWeakBases = 0;
+    std::string basePaths;
+    auto BaseMatchesCallback = [&](const CXXBaseSpecifier* cxxBaseSpecifier, CXXBasePath& Paths) {
+        if (!cxxBaseSpecifier->getType().getTypePtr())
+            return false;
+        const CXXRecordDecl* baseCXXRecordDecl = cxxBaseSpecifier->getType()->getAsCXXRecordDecl();
+        if (!baseCXXRecordDecl)
+            return false;
+        if (baseCXXRecordDecl->isInvalidDecl())
+            return false;
+        if (baseCXXRecordDecl->getName() != "WeakBase")
+            return false;
+        ++noWeakBases;
+        std::string sPath;
+        for (CXXBasePathElement const& pathElement : Paths)
+        {
+            if (!sPath.empty())
+            {
+                sPath += "->";
+            }
+            if (pathElement.Class->hasDefinition())
+                sPath += pathElement.Class->getNameAsString();
+            else
+                sPath += "???";
+        }
+        sPath += "->";
+        sPath += baseCXXRecordDecl->getNameAsString();
+        if (!basePaths.empty())
+            basePaths += ", ";
+        basePaths += sPath;
+        return false;
+    };
+
+    CXXBasePaths aPaths;
+    recordDecl->lookupInBases(BaseMatchesCallback, aPaths);
+
+    if (noWeakBases > 1)
+    {
+        report(DiagnosticsEngine::Warning,
+               "multiple copies of WeakBase, through inheritance paths %0",
+               compat::getBeginLoc(recordDecl))
+            << basePaths << recordDecl->getSourceRange();
+    }
+    return true;
+}
+
+loplugin::Plugin::Registration<WeakBase> WeakBase("weakbase", true);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */