make (some) clang plugins share the same RecursiveASTVisitor

Each plugin currently uses its own recursive AST run, which adds up.
This patch adds another shared plugin which internally contains all
(suitable) plugins and dispatches to them from the same one recursive
run. This patch converts ~25 plugins and for starmath's accessibility.cxx
reduces clang build time from 5.43s to 5.14s (and it's 4.39s without any
plugins). As there are almost 50 more plugins to go, this can theoretically
result in 4.56s final time, although probably not all plugins can be
that easily converted, if at all.

This mostly requires very little change in many plugins (see e.g.
BadStatics), some even work without any functionality change (e.g.
CharRightShift). Traverse* calls require some changes but are often
not that difficult. WalkUp* probably can't be supported, although some
plugins can(?) possibly be adjusted to not rely on them. And of course
some plugins can be left as they are, using their own recursive run.
See description at the top of generator.cxx for description of how to
convert a plugin.

The sharedvisitor.cxx source is generated based on scanning relevant
plugin sources using a clang-based scanner/generator. The generated
source is intentionally included instead of getting always generated,
as the generating currently takes some time, so it should get updated
in git whenever a change in a plugin triggers a source change in it.

Change-Id: Ia0d2e3a5a464659503dbb4ed6c20b6cc89b4de01
Reviewed-on: https://gerrit.libreoffice.org/68026
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

37 files changed, 1862 insertions, 81 deletions

diff --git a/compilerplugins/Makefile-clang.mk b/compilerplugins/Makefile-clang.mk
index 36784fbb4f14..af61c14e1664 100644
--- a/compilerplugins/Makefile-clang.mk
+++ b/compilerplugins/Makefile-clang.mk
@@ -22,6 +22,10 @@ else
 CLANGCXXFLAGS=-O2 -Wall -Wextra -Wundef -g
 endif
 
+# Whether to make plugins use one shared ASTRecursiveVisitor (plugins run faster).
+# By default enabled, disable if you work on an affected plugin (re-generating takes time).
+LO_CLANG_SHARED_PLUGINS=1
+
 # The uninteresting rest.
 
 include $(SRCDIR)/solenv/gbuild/gbuild.mk
@@ -50,6 +54,8 @@ else
 CLANGINCLUDES=$(if $(filter /usr,$(CLANGDIR)),,-isystem $(CLANGDIR)/include)
 endif
 
+LLVMCONFIG=$(CLANGDIR)/bin/llvm-config
+
 # Clang/LLVM libraries are intentionally not linked in, they are usually built as static libraries, which means the resulting
 # plugin would be big (even though the clang binary already includes it all) and it'd be necessary to explicitly specify
 # also all the dependency libraries.
@@ -59,6 +65,10 @@ CLANGINDIR=$(SRCDIR)/compilerplugins/clang
 # plugin will cause cache misses with ccache.
 CLANGOUTDIR=$(BUILDDIR)/compilerplugins/obj
 
+ifdef LO_CLANG_SHARED_PLUGINS
+CLANGCXXFLAGS+=-DLO_CLANG_SHARED_PLUGINS
+endif
+
 QUIET=$(if $(verbose),,@)
 
 ifneq ($(ENABLE_WERROR),)
@@ -72,8 +82,13 @@ endif
 
 compilerplugins: compilerplugins-build
 
+ifdef LO_CLANG_SHARED_PLUGINS
+# The shared source, intentionally put first in the list because it takes the longest to build.
+CLANGSRC=sharedvisitor/sharedvisitor.cxx
+endif
 # The list of source files, generated automatically (all files in clang/, but not subdirs).
-CLANGSRC=$(foreach src,$(wildcard $(CLANGINDIR)/*.cxx), $(notdir $(src)))
+CLANGSRC+=$(foreach src,$(wildcard $(CLANGINDIR)/*.cxx), $(notdir $(src)))
+
 # Remember the sources and if they have changed, force plugin relinking.
 CLANGSRCCHANGED= \
     $(shell mkdir -p $(CLANGOUTDIR) ; \
@@ -152,4 +167,35 @@ endif
 $(CLANGOUTDIR)/clang-timestamp: $(CLANGDIR)/bin/clang$(CLANG_EXE_EXT)
 	$(QUIET)touch $@
 
+
+ifdef LO_CLANG_SHARED_PLUGINS
+# Update the shared visitor source if needed. It is intentionally included in the sources and generated only when
+# needed, because the generating takes a while.
+# If you want to remake the source with LO_CLANG_SHARED_PLUGINS disabled, run 'make LO_CLANG_SHARED_PLUGINS=1'.
+$(CLANGINDIR)/sharedvisitor/sharedvisitor.cxx: $(shell grep -l "LO_CLANG_SHARED_PLUGINS" $(CLANGINDIR)/*.cxx)
+$(CLANGINDIR)/sharedvisitor/sharedvisitor.cxx: $(CLANGOUTDIR)/sharedvisitor/generator$(CLANG_EXE_EXT)
+	$(call gb_Output_announce,$(subst $(SRCDIR)/,,$@),$(true),GEN,1)
+	$(CLANGOUTDIR)/sharedvisitor/generator$(CLANG_EXE_EXT) $(shell grep -l "LO_CLANG_SHARED_PLUGINS" $(CLANGINDIR)/*.cxx) \
+        > $(CLANGINDIR)/sharedvisitor/sharedvisitor.cxx
+
+CLANGTOOLLIBS = -lclangTooling -lclangDriver -lclangFrontend -lclangParse -lclangSema -lclangEdit -lclangAnalysis \
+        -lclangAST -lclangLex -lclangSerialization -lclangBasic $(shell $(LLVMCONFIG) --ldflags --libs --system-libs)
+# Path to the clang system headers (no idea if there's a better way to get it).
+CLANGTOOLDEFS = -DCLANGSYSINCLUDE=$(shell $(LLVMCONFIG) --libdir)/clang/$(shell $(LLVMCONFIG) --version | sed 's/svn//')/include
+
+$(CLANGOUTDIR)/sharedvisitor/generator$(CLANG_EXE_EXT): $(CLANGINDIR)/sharedvisitor/generator.cxx
+	$(call gb_Output_announce,$(subst $(BUILDDIR)/,,$@),$(true),GEN,1)
+	$(QUIET)$(COMPILER_PLUGINS_CXX) $(CLANGCXXFLAGS) $(CLANGWERROR) $(CLANGDEFS) $(CLANGTOOLDEFS) $(CLANGINCLUDES) \
+        -DCLANGDIR=$(CLANGDIR) -DBUILDDIR=$(BUILDDIR) -I$(BUILDDIR)/config_host \
+        $< -o $@ -MMD -MT $@ -MP -MF $(CLANGOUTDIR)/sharedvisitor/generator.d $(CLANGTOOLLIBS)
+
+compilerplugins-build: $(CLANGOUTDIR)/sharedvisitor
+
+$(CLANGOUTDIR)/sharedvisitor:
+	mkdir -p $(CLANGOUTDIR)/sharedvisitor
+
+-include $(CLANGOUTDIR)/sharedvisitor/generator.d
+# TODO WNT version
+endif
+
 # vim: set noet sw=4 ts=4:
diff --git a/compilerplugins/clang/badstatics.cxx b/compilerplugins/clang/badstatics.cxx
index 4eebb46d96f3..16e304981669 100644
--- a/compilerplugins/clang/badstatics.cxx
+++ b/compilerplugins/clang/badstatics.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
 
 #include "check.hxx"
@@ -22,8 +24,12 @@ public:
     explicit BadStatics(loplugin::InstantiationData const& rData):
         FilteringPlugin(rData) {}
 
+    bool preRun() override {
+        return compiler.getLangOpts().CPlusPlus; // no non-trivial dtors in C
+    }
+
     void run() override {
-        if (compiler.getLangOpts().CPlusPlus) { // no non-trivial dtors in C
+        if (preRun()) {
             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
         }
     }
@@ -244,8 +250,10 @@ public:
 
 };
 
-loplugin::Plugin::Registration<BadStatics> X("badstatics");
+loplugin::Plugin::Registration<BadStatics> badstatics("badstatics");
 
 } // namespace
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/blockblock.cxx b/compilerplugins/clang/blockblock.cxx
index 9358845abc47..8405609af3df 100644
--- a/compilerplugins/clang/blockblock.cxx
+++ b/compilerplugins/clang/blockblock.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
 #include <string>
 #include <iostream>
@@ -26,13 +28,18 @@ public:
     explicit BlockBlock(loplugin::InstantiationData const & data):
         FilteringPlugin(data) {}
 
-    virtual void run() override
+    virtual bool preRun() override
     {
         StringRef fn(handler.getMainFileName());
         if (loplugin::isSamePathname(fn, SRCDIR "/sal/osl/unx/file_misc.cxx"))
-             return;
+             return false;
+        return true;
+    }
 
-        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+    void run() override {
+        if (preRun()) {
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+        }
     }
 
     bool VisitCompoundStmt(CompoundStmt const * );
@@ -67,8 +74,10 @@ bool BlockBlock::VisitCompoundStmt(CompoundStmt const * compound)
     return true;
 }
 
-loplugin::Plugin::Registration< BlockBlock > X("blockblock", true);
+loplugin::Plugin::Registration< BlockBlock > blockblock("blockblock", true);
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/charrightshift.cxx b/compilerplugins/clang/charrightshift.cxx
index aa4c85d3f22d..6f3027002daa 100644
--- a/compilerplugins/clang/charrightshift.cxx
+++ b/compilerplugins/clang/charrightshift.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "check.hxx"
 #include "plugin.hxx"
 
@@ -51,8 +53,10 @@ public:
     }
 };
 
-loplugin::Plugin::Registration<CharRightShift> X("charrightshift");
+loplugin::Plugin::Registration<CharRightShift> charrightshift("charrightshift");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/check.hxx b/compilerplugins/clang/check.hxx
index 0d636636a81a..fd4d46fd0b97 100644
--- a/compilerplugins/clang/check.hxx
+++ b/compilerplugins/clang/check.hxx
@@ -115,6 +115,8 @@ public:
 
     inline ContextCheck Struct(llvm::StringRef id) const;
 
+    explicit ContextCheck(const clang::NamespaceDecl * decl ) : context_( decl ) {}
+
 private:
     friend DeclCheck;
     friend TypeCheck;
diff --git a/compilerplugins/clang/datamembershadow.cxx b/compilerplugins/clang/datamembershadow.cxx
index 6c7f866761a8..d325650becea 100644
--- a/compilerplugins/clang/datamembershadow.cxx
+++ b/compilerplugins/clang/datamembershadow.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <string>
 #include <iostream>
 #include <map>
@@ -114,8 +116,10 @@ bool DataMemberShadow::VisitFieldDecl(FieldDecl const * fieldDecl)
     return true;
 }
 
-loplugin::Plugin::Registration< DataMemberShadow > X("datamembershadow", true);
+loplugin::Plugin::Registration< DataMemberShadow > datamembershadow("datamembershadow", true);
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/dbgunhandledexception.cxx b/compilerplugins/clang/dbgunhandledexception.cxx
index e701b38849f2..81d6126fb3af 100644
--- a/compilerplugins/clang/dbgunhandledexception.cxx
+++ b/compilerplugins/clang/dbgunhandledexception.cxx
@@ -9,6 +9,8 @@
  *
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "check.hxx"
 #include "plugin.hxx"
 #include <clang/Lex/Lexer.h>
@@ -31,9 +33,11 @@ public:
     virtual void run() override;
     bool VisitCallExpr(CallExpr const* call);
     bool TraverseCXXCatchStmt(CXXCatchStmt*);
+    bool PreTraverseCXXCatchStmt(CXXCatchStmt*);
+    bool PostTraverseCXXCatchStmt(CXXCatchStmt*, bool traverseOk);
 
 private:
-    CXXCatchStmt const* currCatchStmt = nullptr;
+    std::stack<CXXCatchStmt const*> currCatchStmt;
 };
 
 DbgUnhandledException::DbgUnhandledException(const InstantiationData& data)
@@ -46,13 +50,27 @@ void DbgUnhandledException::run()
     TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
 }
 
+bool DbgUnhandledException::PreTraverseCXXCatchStmt(CXXCatchStmt* catchStmt)
+{
+    currCatchStmt.push(catchStmt);
+    return true;
+}
+
+bool DbgUnhandledException::PostTraverseCXXCatchStmt(CXXCatchStmt* catchStmt, bool)
+{
+    assert(currCatchStmt.top() == catchStmt);
+    currCatchStmt.pop();
+    return true;
+}
+
 bool DbgUnhandledException::TraverseCXXCatchStmt(CXXCatchStmt* catchStmt)
 {
-    auto prevCatchStmt = currCatchStmt;
-    currCatchStmt = catchStmt;
-    auto rv = RecursiveASTVisitor::TraverseCXXCatchStmt(catchStmt);
-    currCatchStmt = prevCatchStmt;
-    return rv;
+    if (!PreTraverseCXXCatchStmt(catchStmt))
+        return false;
+    bool ret = RecursiveASTVisitor::TraverseCXXCatchStmt(catchStmt);
+    if (!PostTraverseCXXCatchStmt(catchStmt, ret))
+        return false;
+    return ret;
 }
 
 bool DbgUnhandledException::VisitCallExpr(const CallExpr* call)
@@ -66,13 +84,13 @@ bool DbgUnhandledException::VisitCallExpr(const CallExpr* call)
     if (!func->getIdentifier() || func->getName() != "DbgUnhandledException")
         return true;
 
-    if (!currCatchStmt)
+    if (currCatchStmt.empty())
     {
         report(DiagnosticsEngine::Warning, "DBG_UNHANDLED_EXCEPTION outside catch block",
                compat::getBeginLoc(call));
         return true;
     }
-    auto catchBlock = dyn_cast<CompoundStmt>(currCatchStmt->getHandlerBlock());
+    auto catchBlock = dyn_cast<CompoundStmt>(currCatchStmt.top()->getHandlerBlock());
     if (!catchBlock)
     {
         report(DiagnosticsEngine::Warning,
@@ -100,8 +118,10 @@ bool DbgUnhandledException::VisitCallExpr(const CallExpr* call)
     return true;
 }
 
-static Plugin::Registration<DbgUnhandledException> X("dbgunhandledexception");
+static Plugin::Registration<DbgUnhandledException> dbgunhandledexception("dbgunhandledexception");
 
 } // namespace
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/derefnullptr.cxx b/compilerplugins/clang/derefnullptr.cxx
index cc5ffe431a2f..61ffbfab24df 100644
--- a/compilerplugins/clang/derefnullptr.cxx
+++ b/compilerplugins/clang/derefnullptr.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "plugin.hxx"
 
 namespace {
@@ -38,8 +40,10 @@ bool DerefNullPtr::VisitUnaryDeref(UnaryOperator const * op) {
     return true;
 }
 
-loplugin::Plugin::Registration<DerefNullPtr> X("derefnullptr");
+loplugin::Plugin::Registration<DerefNullPtr> derefnullptr("derefnullptr");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/doubleconvert.cxx b/compilerplugins/clang/doubleconvert.cxx
index ea93084511cf..95565301b751 100644
--- a/compilerplugins/clang/doubleconvert.cxx
+++ b/compilerplugins/clang/doubleconvert.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "check.hxx"
 #include "compat.hxx"
 #include "plugin.hxx"
@@ -78,7 +80,9 @@ bool DoubleConvert::VisitMaterializeTemporaryExpr(MaterializeTemporaryExpr const
     return true;
 }
 
-static loplugin::Plugin::Registration<DoubleConvert> reg("doubleconvert");
+static loplugin::Plugin::Registration<DoubleConvert> doubleconvert("doubleconvert");
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/dyncastvisibility.cxx b/compilerplugins/clang/dyncastvisibility.cxx
index 8b29f0735ca9..0f6021101e2b 100644
--- a/compilerplugins/clang/dyncastvisibility.cxx
+++ b/compilerplugins/clang/dyncastvisibility.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
@@ -184,17 +186,22 @@ public:
         return true;
     }
 
+    virtual bool preRun() override {
+        return compiler.getLangOpts().CPlusPlus;
+    }
 private:
     void run() override {
-        if (compiler.getLangOpts().CPlusPlus) {
+        if (preRun()) {
             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
         }
     }
 };
 
-static loplugin::Plugin::Registration<DynCastVisibility> reg(
+static loplugin::Plugin::Registration<DynCastVisibility> dyncastvisibility(
     "dyncastvisibility");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/empty.cxx b/compilerplugins/clang/empty.cxx
index 74cc7b06e176..4d48ca620087 100644
--- a/compilerplugins/clang/empty.cxx
+++ b/compilerplugins/clang/empty.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
 
 #include "check.hxx"
@@ -180,7 +182,9 @@ private:
     }
 };
 
-loplugin::Plugin::Registration<Empty> X("empty");
+loplugin::Plugin::Registration<Empty> emptyRegistration("empty");
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/emptyif.cxx b/compilerplugins/clang/emptyif.cxx
index 76f9c033018e..ef7eac50d048 100644
--- a/compilerplugins/clang/emptyif.cxx
+++ b/compilerplugins/clang/emptyif.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
 #include <string>
 #include <iostream>
@@ -84,7 +86,9 @@ bool EmptyIf::VisitIfStmt(IfStmt const* ifStmt)
     return true;
 }
 
-loplugin::Plugin::Registration<EmptyIf> X("emptyif", true);
+loplugin::Plugin::Registration<EmptyIf> emptyif("emptyif", true);
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/externandnotdefined.cxx b/compilerplugins/clang/externandnotdefined.cxx
index afd77abe7bda..72b250d3d82e 100644
--- a/compilerplugins/clang/externandnotdefined.cxx
+++ b/compilerplugins/clang/externandnotdefined.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <string>
 
 #include "plugin.hxx"
@@ -71,8 +73,10 @@ bool ExternAndNotDefined::VisitFunctionDecl(const FunctionDecl * functionDecl) {
 }
 
 
-loplugin::Plugin::Registration< ExternAndNotDefined > X("externandnotdefined");
+loplugin::Plugin::Registration< ExternAndNotDefined > externandnotdefined("externandnotdefined");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/externvar.cxx b/compilerplugins/clang/externvar.cxx
index 93a08092bd08..eb20d3f36b0d 100644
--- a/compilerplugins/clang/externvar.cxx
+++ b/compilerplugins/clang/externvar.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "check.hxx"
 #include "plugin.hxx"
 
@@ -109,8 +111,10 @@ public:
     }
 };
 
-loplugin::Plugin::Registration<ExternVar> X("externvar");
+loplugin::Plugin::Registration<ExternVar> externvar("externvar");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/inlinevisible.cxx b/compilerplugins/clang/inlinevisible.cxx
index c32eb9b0d74c..8e232a337837 100644
--- a/compilerplugins/clang/inlinevisible.cxx
+++ b/compilerplugins/clang/inlinevisible.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
 #include <string>
 
@@ -46,8 +48,10 @@ bool InlineVisible::VisitFunctionDecl(FunctionDecl const * decl) {
     return true;
 }
 
-loplugin::Plugin::Registration<InlineVisible> X("inlinevisible");
+loplugin::Plugin::Registration<InlineVisible> inlinevisible("inlinevisible");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/loopvartoosmall.cxx b/compilerplugins/clang/loopvartoosmall.cxx
index 7ebe34f22474..896266385dea 100644
--- a/compilerplugins/clang/loopvartoosmall.cxx
+++ b/compilerplugins/clang/loopvartoosmall.cxx
@@ -9,6 +9,8 @@
  *
 */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <algorithm>
 #include <cassert>
 #include <list>
@@ -234,8 +236,10 @@ void LoopVarTooSmall::checkExpr(Expr const * expr) {
     }
 }
 
-loplugin::Plugin::Registration< LoopVarTooSmall > X("loopvartoosmall");
+loplugin::Plugin::Registration< LoopVarTooSmall > loopvartoosmall("loopvartoosmall");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/plugin.cxx b/compilerplugins/clang/plugin.cxx
index 2167cc0e2a7f..1a1ca44a91ab 100644
--- a/compilerplugins/clang/plugin.cxx
+++ b/compilerplugins/clang/plugin.cxx
@@ -154,9 +154,10 @@ void normalizeDotDotInFilePath( std::string & s )
     }
 }
 
-void Plugin::registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName, bool isPPCallback, bool byDefault )
+void Plugin::registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName,
+    bool isPPCallback, bool isSharedPlugin, bool byDefault )
 {
-    PluginHandler::registerPlugin( create, optionName, isPPCallback, byDefault );
+    PluginHandler::registerPlugin( create, optionName, isPPCallback, isSharedPlugin, byDefault );
 }
 
 bool Plugin::evaluate(const Expr* expr, APSInt& x)
diff --git a/compilerplugins/clang/plugin.hxx b/compilerplugins/clang/plugin.hxx
index 4aab4beb4b8d..19908d8257e5 100644
--- a/compilerplugins/clang/plugin.hxx
+++ b/compilerplugins/clang/plugin.hxx
@@ -51,11 +51,20 @@ class Plugin
 public:
     explicit Plugin( const InstantiationData& data );
     virtual ~Plugin() {}
+    // The main function of the plugin.
+    // Note that for shared plugins, its functionality must be split into preRun() and postRun(),
+    // see sharedvisitor/generator.cxx .
     virtual void run() = 0;
+    // Should be called from run() before TraverseDecl().
+    // If returns false, run() should not do anything.
+    virtual bool preRun() { return true; }
+    virtual void postRun() {}
     template< typename T > class Registration;
-    enum { isPPCallback = false };
     // Returns location right after the end of the token that starts at the given location.
     SourceLocation locationAfterToken( SourceLocation location );
+    virtual bool setSharedPlugin( Plugin* /*plugin*/, const char* /*name*/ ) { return false; }
+    enum { isPPCallback = false };
+    enum { isSharedPlugin = false };
 protected:
     DiagnosticBuilder report( DiagnosticsEngine::Level level, StringRef message, SourceLocation loc = SourceLocation()) const;
     bool ignoreLocation( SourceLocation loc ) const
@@ -92,7 +101,8 @@ protected:
         Expr const * argument1, Expr const * argument2);
 
 private:
-    static void registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName, bool isPPCallback, bool byDefault );
+    static void registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName,
+        bool isPPCallback, bool isSharedPlugin, bool byDefault );
     template< typename T > static Plugin* createHelper( const InstantiationData& data );
     bool evaluate(const Expr* expr, APSInt& x);
 
@@ -220,7 +230,7 @@ template< typename T >
 inline
 Plugin::Registration< T >::Registration( const char* optionName, bool byDefault )
 {
-    registerPlugin( &T::template createHelper< T >, optionName, T::isPPCallback, byDefault );
+    registerPlugin( &T::template createHelper< T >, optionName, T::isPPCallback, T::isSharedPlugin, byDefault );
 }
 
 inline
diff --git a/compilerplugins/clang/pluginhandler.cxx b/compilerplugins/clang/pluginhandler.cxx
index 540e58dcd222..4296b981f767 100644
--- a/compilerplugins/clang/pluginhandler.cxx
+++ b/compilerplugins/clang/pluginhandler.cxx
@@ -46,7 +46,9 @@ struct PluginData
     Plugin* object;
     const char* optionName;
     bool isPPCallback;
+    bool isSharedPlugin;
     bool byDefault;
+    bool disabledRun;
 };
 
 const int MAX_PLUGINS = 200;
@@ -150,9 +152,26 @@ void PluginHandler::createPlugins( std::set< std::string > rewriters )
     }
     for( auto r: rewriters )
         report( DiagnosticsEngine::Fatal, "unknown plugin tool %0" ) << r;
+    // If there is a shared plugin, make it handle all plugins that it can handle.
+    for( int i = 0; i < pluginCount; ++i )
+    {
+        if( plugins[ i ].isSharedPlugin && plugins[ i ].object != nullptr )
+        {
+            Plugin* plugin = plugins[ i ].object;
+            for( int j = 0; j < pluginCount; ++j )
+            {
+                if( plugins[ j ].object != nullptr
+                    && plugin->setSharedPlugin( plugins[ j ].object, plugins[ j ].optionName ))
+                {
+                    plugins[ j ].disabledRun = true;
+                }
+            }
+        }
+    }
 }
 
-void PluginHandler::registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName, bool isPPCallback, bool byDefault )
+void PluginHandler::registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName,
+    bool isPPCallback, bool isSharedPlugin, bool byDefault )
 {
     assert( !bPluginObjectsCreated );
     assert( pluginCount < MAX_PLUGINS );
@@ -160,7 +179,9 @@ void PluginHandler::registerPlugin( Plugin* (*create)( const InstantiationData&
     plugins[ pluginCount ].object = NULL;
     plugins[ pluginCount ].optionName = optionName;
     plugins[ pluginCount ].isPPCallback = isPPCallback;
+    plugins[ pluginCount ].isSharedPlugin = isSharedPlugin;
     plugins[ pluginCount ].byDefault = byDefault;
+    plugins[ pluginCount ].disabledRun = false;
     ++pluginCount;
 }
 
@@ -281,7 +302,7 @@ void PluginHandler::HandleTranslationUnit( ASTContext& context )
 
     for( int i = 0; i < pluginCount; ++i )
     {
-        if( plugins[ i ].object != NULL )
+        if( plugins[ i ].object != NULL && !plugins[ i ].disabledRun )
         {
             plugins[ i ].object->run();
         }
diff --git a/compilerplugins/clang/pluginhandler.hxx b/compilerplugins/clang/pluginhandler.hxx
index d51afebccac7..10b4ae21df2b 100644
--- a/compilerplugins/clang/pluginhandler.hxx
+++ b/compilerplugins/clang/pluginhandler.hxx
@@ -50,7 +50,8 @@ public:
     PluginHandler( CompilerInstance& compiler, const std::vector< std::string >& args );
     virtual ~PluginHandler();
     virtual void HandleTranslationUnit( ASTContext& context ) override;
-    static void registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName, bool isPPCallback, bool byDefault );
+    static void registerPlugin( Plugin* (*create)( const InstantiationData& ), const char* optionName,
+        bool isPPCallback, bool isSharedPlugin, bool byDefault );
     DiagnosticBuilder report( DiagnosticsEngine::Level level, const char * plugin, StringRef message,
             CompilerInstance& compiler, SourceLocation loc = SourceLocation());
     bool ignoreLocation(SourceLocation loc);
diff --git a/compilerplugins/clang/privatebase.cxx b/compilerplugins/clang/privatebase.cxx
index 5e92aaa7ea9c..6819647f88c5 100644
--- a/compilerplugins/clang/privatebase.cxx
+++ b/compilerplugins/clang/privatebase.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "plugin.hxx"
 
 namespace {
@@ -48,8 +50,10 @@ bool PrivateBase::VisitCXXRecordDecl(CXXRecordDecl const * decl) {
     return true;
 }
 
-loplugin::Plugin::Registration<PrivateBase> X("privatebase");
+loplugin::Plugin::Registration<PrivateBase> privatebase("privatebase");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/reservedid.cxx b/compilerplugins/clang/reservedid.cxx
index f05890cda0a5..acdc18217514 100644
--- a/compilerplugins/clang/reservedid.cxx
+++ b/compilerplugins/clang/reservedid.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <algorithm>
 #include <cassert>
 #include <limits>
@@ -40,6 +42,7 @@ public:
     {}
 
     void run() override;
+    void postRun() override;
 
     bool VisitNamedDecl(NamedDecl const * decl);
 
@@ -56,8 +59,12 @@ private:
 
 void ReservedId::run() {
     //TODO: Rules for C?
-    if (TraverseDecl(compiler.getASTContext().getTranslationUnitDecl())
-        && compiler.hasPreprocessor())
+    if (TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()))
+        postRun();
+}
+
+void ReservedId::postRun() {
+    if( compiler.hasPreprocessor())
     {
         auto & prep = compiler.getPreprocessor();
         for (auto const & m: prep.macros(false)) {
@@ -302,8 +309,10 @@ bool ReservedId::isApi(NamedDecl const * decl) {
     return false;
 }
 
-loplugin::Plugin::Registration<ReservedId> X("reservedid");
+loplugin::Plugin::Registration<ReservedId> reservedid("reservedid");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/sharedvisitor/generator.cxx b/compilerplugins/clang/sharedvisitor/generator.cxx
new file mode 100644
index 000000000000..c714c0cc69db
--- /dev/null
+++ b/compilerplugins/clang/sharedvisitor/generator.cxx
@@ -0,0 +1,563 @@
+/* -*- 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/.
+ */
+
+/*
+This tool generates another "plugin" which in fact only dispatches Visit* and Traverse*
+calls to all other plugins registered with it. This means that there is just one
+RecursiveASTVisitor pass for all those plugins instead of one per each, which
+with the current number of plugins actually makes a performance difference.
+
+If you work on a plugin, comment out LO_CLANG_SHARED_PLUGINS in Makefile-clang.mk in order
+to disable the feature (re-generating takes time).
+
+Requirements for plugins:
+- Can use Visit* and Traverse* functions, but not WalkUp*.
+- Visit* functions can generally remain unmodified.
+- run() function must be split into preRun() and postRun() if there's any additional functionality
+  besides calling TraverseDecl(). The shared visitor will call the preRun() and postRun() functions
+  as necessary while calling its own run(). The run() function of the plugin must stay
+  (in case of a non-shared build) but should generally look like this:
+    if( preRun())
+        if( TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()))
+            postRun();
+- Traverse* functions must be split into PreTraverse* and PostTraverse*, similarly to how run()
+  is handled, the Traverse* function should generally look like this:
+        bool ret = true;
+        if( PreTraverse*(decl))
+        {
+            ret = RecursiveASTVisitor::Traverse*(decl);
+            PostTraverse*(decl, ret);
+        }
+        return ret;
+
+
+TODO:
+- Create macros for the standardized layout of run(), Traverse*, etc.?
+- Possibly check plugin sources more thoroughly (e.g. that run() doesn't actually do more).
+- Have one tool that extracts info from plugin .cxx files into some .txt file and another tool
+  that generates sharedvisitor.cxx based on those files? That would generally make the generation
+  faster when doing incremental changes. The .txt file could also contain some checksum of the .cxx
+  to avoid the analysing pass completely if just the timestamp has changed.
+- Do not re-compile sharedvisitor.cxx if its contents have not actually changed.
+- Is it possible to make the clang code analyze just the .cxx without also parsing all the headers?
+- Instead of having to comment out LO_CLANG_SHARED_PLUGINS, implement --enable-compiler-plugins=debug .
+
+*/
+
+#include "clang/AST/ASTConsumer.h"
+#include "clang/AST/RecursiveASTVisitor.h"
+#include "clang/Frontend/CompilerInstance.h"
+#include "clang/Frontend/FrontendAction.h"
+#include "clang/Tooling/Tooling.h"
+
+#include <iostream>
+#include <fstream>
+#include <set>
+
+#include "../check.hxx"
+#include "../check.cxx"
+
+using namespace std;
+
+using namespace clang;
+
+using namespace loplugin;
+
+// Info about a Visit* function in a plugin.
+struct VisitFunctionInfo
+{
+    string name;
+    string argument;
+};
+
+
+// Info about a Traverse* function in a plugin.
+struct TraverseFunctionInfo
+{
+    string name;
+    string argument;
+    bool hasPre = false;
+    bool hasPost = false;
+};
+
+struct VisitFunctionInfoLess
+{
+    bool operator()( const VisitFunctionInfo& l, const VisitFunctionInfo& r ) const
+    {
+        return l.name < r.name;
+    }
+};
+
+struct TraverseFunctionInfoLess
+{
+    bool operator()( const TraverseFunctionInfo& l, const TraverseFunctionInfo& r ) const
+    {
+        return l.name < r.name;
+    }
+};
+
+
+// Information about each LO plugin.
+struct PluginInfo
+{
+    string className; // e.g. "BadStatics"
+    string variableName; // e.g. "badStatics"
+    string lowercaseName;
+    bool shouldVisitTemplateInstantiations;
+    bool shouldVisitImplicitCode;
+    set< VisitFunctionInfo, VisitFunctionInfoLess > visitFunctions;
+    set< TraverseFunctionInfo, TraverseFunctionInfoLess > traverseFunctions;
+};
+
+// We need separate visitors for shouldVisitTemplateInstantiations and shouldVisitImplicitCode,
+// so split plugins into groups by what they should visit.
+// It seems that trying to handle the shouldVisit* functionality with just one visitor
+// is tricky.
+enum PluginType
+{
+    PluginBasic,
+    PluginVisitTemplates,
+    PluginVisitImplicit,
+    PluginVisitTemplatesImplicit,
+};
+
+const int Plugin_Begin = PluginBasic;
+const int Plugin_End = PluginVisitTemplatesImplicit + 1;
+static const char* const pluginTypeNames[ Plugin_End ]
+    = { "Basic", "VisitTemplates", "VisitImplicit", "VisitTemplatesImplicit" };
+
+static vector< PluginInfo > plugins[ Plugin_End ];
+
+
+void generateVisitor( PluginType type );
+
+void generate()
+{
+    ostream& output = cout;
+    output <<
+"// This file is autogenerated. Do not modify.\n"
+"// Generated by compilerplugins/clang/sharedvisitor/generator.cxx .\n"
+"\n"
+"#ifdef LO_CLANG_SHARED_PLUGINS\n"
+"\n"
+"#include <config_clang.h>\n"
+"\n"
+"#include <clang/AST/ASTContext.h>\n"
+"#include <clang/AST/RecursiveASTVisitor.h>\n"
+"\n"
+"#include \"../plugin.hxx\"\n"
+"\n";
+
+    output << "#undef LO_CLANG_SHARED_PLUGINS // to get sources of individual plugins\n";
+    for( const auto& pluginGroup : plugins )
+        for( const PluginInfo& plugin : pluginGroup )
+            output << "#include \"../" << plugin.lowercaseName << ".cxx\"" << endl;
+
+    output <<
+"\n"
+"using namespace clang;\n"
+"using namespace llvm;\n"
+"\n"
+"namespace loplugin\n"
+"{\n";
+
+    for( int type = Plugin_Begin; type < Plugin_End; ++type )
+        generateVisitor( static_cast< PluginType >( type ));
+
+    output <<
+"} // namespace loplugin\n"
+"\n"
+"#endif // LO_CLANG_SHARED_PLUGINS\n";
+};
+
+void generateVisitor( PluginType type )
+{
+    if( plugins[ type ].empty())
+        return;
+    ostream& output = cout;
+    output <<
+"\n"
+"class SharedRecursiveASTVisitor" << pluginTypeNames[ type ] << "\n"
+"    : public FilteringPlugin< SharedRecursiveASTVisitor" << pluginTypeNames[ type ] << ">\n"
+"{\n"
+"public:\n"
+"    explicit SharedRecursiveASTVisitor" << pluginTypeNames[ type ] << "(const InstantiationData& rData)\n"
+"        : FilteringPlugin(rData)\n";
+    for( const PluginInfo& plugin : plugins[ type ] )
+        output << "        , " << plugin.variableName << "( nullptr )\n";
+    output << "        {}\n";
+
+    output <<
+"    virtual bool preRun() override\n"
+"    {\n";
+    for( const PluginInfo& plugin : plugins[ type ] )
+    {
+        output << "        if( " << plugin.variableName << " && !" << plugin.variableName << "->preRun())\n";
+        // This will disable the plugin for the rest of the run.
+        output << "            " << plugin.variableName << " = nullptr;\n";
+    }
+    output <<
+"        return anyPluginActive();\n"
+"    }\n";
+
+    output <<
+"    virtual void postRun() override\n"
+"    {\n";
+    for( const PluginInfo& plugin : plugins[ type ] )
+    {
+        output << "        if( " << plugin.variableName << " )\n";
+        output << "            " << plugin.variableName << "->postRun();\n";
+    }
+    output <<
+"    }\n";
+
+    output <<
+"    virtual void run() override {\n"
+"        if (preRun()) {\n"
+"            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());\n"
+"            postRun();\n"
+"        }\n"
+"    }\n"
+"    enum { isSharedPlugin = true };\n";
+
+    output <<
+"    virtual bool setSharedPlugin( Plugin* plugin, const char* name ) override\n"
+"    {\n";
+    bool first = true;
+    for( const PluginInfo& plugin : plugins[ type ] )
+    {
+        output << "        ";
+        if( !first )
+            output << "else ";
+        first = false;
+        output << "if( strcmp( name, \"" << plugin.lowercaseName << "\" ) == 0 )\n";
+        output << "            " << plugin.variableName << " = static_cast< " << plugin.className << "* >( plugin );\n";
+    }
+    output <<
+"        else\n"
+"            return false;\n"
+"        return true;\n"
+"    }\n";
+
+    if( type == PluginVisitTemplates || type == PluginVisitTemplatesImplicit )
+        output << "bool shouldVisitTemplateInstantiations() const { return true; }\n";
+    if( type == PluginVisitImplicit || type == PluginVisitTemplatesImplicit )
+        output << "bool shouldVisitImplicitCode() const { return true; }\n";
+
+    set< VisitFunctionInfo, VisitFunctionInfoLess > visitFunctions;
+    for( const PluginInfo& plugin : plugins[ type ] )
+        for( const VisitFunctionInfo& visit : plugin.visitFunctions )
+            visitFunctions.insert( visit );
+    for( const VisitFunctionInfo& visit : visitFunctions )
+    {
+        output << "    bool " << visit.name << "(" << visit.argument << " arg)\n";
+        output <<
+"    {\n"
+"        if( ignoreLocation( arg ))\n"
+"            return true;\n";
+        for( const PluginInfo& plugin : plugins[ type ] )
+        {
+            if( plugin.visitFunctions.find( visit ) == plugin.visitFunctions.end())
+                continue;
+            output << "        if( " << plugin.variableName << " != nullptr ";
+            output << ")\n";
+            output << "        {\n";
+            output << "            if( !" << plugin.variableName << "->" << visit.name << "( arg ))\n";
+            // This will disable the plugin for the rest of the run (as would returning false
+            // from Visit* normally do in the non-shared case).
+            output << "                " << plugin.variableName << " = nullptr;\n";
+            output << "        }\n";
+        }
+        output <<
+"        return anyPluginActive();\n"
+"    }\n";
+    }
+
+    set< TraverseFunctionInfo, TraverseFunctionInfoLess > traverseFunctions;
+    for( const PluginInfo& plugin : plugins[ type ] )
+        for( const TraverseFunctionInfo& traverse : plugin.traverseFunctions )
+            traverseFunctions.insert( traverse );
+    for( const TraverseFunctionInfo& traverse : traverseFunctions )
+    {
+        output << "    bool " << traverse.name << "(" << traverse.argument << " arg)\n";
+        output << "    {\n";
+        for( const PluginInfo& plugin : plugins[ type ] )
+        {
+            auto pluginTraverse = plugin.traverseFunctions.find( traverse );
+            if( pluginTraverse == plugin.traverseFunctions.end())
+                continue;
+            output << "        " << plugin.className << "* save" << plugin.className << " = " << plugin.variableName << ";\n";
+            if( pluginTraverse->hasPre )
+            {
+                output << "        if( " << plugin.variableName << " != nullptr ";
+                output << ")\n";
+                output << "        {\n";
+                output << "            if( !" << plugin.variableName << "->Pre" << traverse.name << "( arg ))\n";
+                // This will disable the plugin for the time of the traverse, until restored later,
+                // just like directly returning from Traverse* would skip that part.
+                output << "                " << plugin.variableName << " = nullptr;\n";
+                output << "        }\n";
+            }
+        }
+        output << "        bool ret = RecursiveASTVisitor::" << traverse.name << "( arg );\n";
+        for( const PluginInfo& plugin : plugins[ type ] )
+        {
+            auto pluginTraverse = plugin.traverseFunctions.find( traverse );
+            if( pluginTraverse == plugin.traverseFunctions.end())
+                continue;
+            if( pluginTraverse->hasPost )
+            {
+                output << "        if( " << plugin.variableName << " != nullptr ";
+                output << ")\n";
+                output << "        {\n";
+                output << "            if( !" << plugin.variableName << "->Post" << traverse.name << "( arg, ret ))\n";
+                // This will disable the plugin for the rest of the run.
+                output << "                save" << plugin.className << " = nullptr;\n";
+                output << "        }\n";
+            }
+            output << "        " << plugin.variableName << " = save" << plugin.className << ";\n";
+        }
+        output << "        return ret;\n";
+        output << "    }\n";
+    }
+
+    output <<
+"private:\n";
+
+    output <<
+"    bool anyPluginActive() const\n"
+"    {\n";
+    first = true;
+    for( const PluginInfo& plugin : plugins[ type ] )
+    {
+        if( first )
+            output << "        return " << plugin.variableName << " != nullptr";
+        else
+            output << "\n            || " << plugin.variableName << " != nullptr";
+        first = false;
+    }
+    output << ";\n";
+    output << "    }\n";
+
+    for( const PluginInfo& plugin : plugins[ type ] )
+        output << "    " << plugin.className << "* " << plugin.variableName << ";\n";
+
+    output <<
+"};\n"
+"\n"
+"loplugin::Plugin::Registration< SharedRecursiveASTVisitor" << pluginTypeNames[ type ]
+    << " > registration" << pluginTypeNames[ type ] << "(\"sharedvisitor" << pluginTypeNames[ type ] << "\");\n"
+"\n";
+}
+
+class CheckFileVisitor
+    : public RecursiveASTVisitor< CheckFileVisitor >
+{
+public:
+    bool VisitCXXRecordDecl(CXXRecordDecl *Declaration);
+
+    bool TraverseNamespaceDecl(NamespaceDecl * decl)
+    {
+        // Skip non-LO namespaces the same way FilteringPlugin does.
+        if( !ContextCheck( decl ).Namespace( "loplugin" ).GlobalNamespace()
+            && !ContextCheck( decl ).AnonymousNamespace())
+        {
+            return true;
+        }
+        return RecursiveASTVisitor<CheckFileVisitor>::TraverseNamespaceDecl(decl);
+    }
+};
+
+static bool inheritsPluginClassCheck( const Decl* decl )
+{
+    return bool( DeclCheck( decl ).Class( "FilteringPlugin" ).Namespace( "loplugin" ).GlobalNamespace())
+        || bool( DeclCheck( decl ).Class( "FilteringRewritePlugin" ).Namespace( "loplugin" ).GlobalNamespace());
+}
+
+static TraverseFunctionInfo findOrCreateTraverseFunctionInfo( PluginInfo& pluginInfo, StringRef name )
+{
+    TraverseFunctionInfo info;
+    info.name = name;
+    auto foundInfo = pluginInfo.traverseFunctions.find( info );
+    if( foundInfo != pluginInfo.traverseFunctions.end())
+    {
+        info = move( *foundInfo );
+        pluginInfo.traverseFunctions.erase( foundInfo );
+    }
+    return info;
+}
+
+bool CheckFileVisitor::VisitCXXRecordDecl( CXXRecordDecl* decl )
+{
+    if( !isDerivedFrom( decl, inheritsPluginClassCheck ))
+        return true;
+
+    if( decl->getName() == "FilteringPlugin" || decl->getName() == "FilteringRewritePlugin" )
+        return true;
+
+    PluginInfo pluginInfo;
+    pluginInfo.className = decl->getName().str();
+    pluginInfo.variableName = pluginInfo.className;
+    assert( pluginInfo.variableName.size() > 0 );
+    pluginInfo.variableName[ 0 ] = tolower( pluginInfo.variableName[ 0 ] );
+    pluginInfo.lowercaseName = pluginInfo.className;
+    for( char& c : pluginInfo.lowercaseName )
+        c = tolower( c );
+    pluginInfo.shouldVisitTemplateInstantiations = false;
+    pluginInfo.shouldVisitImplicitCode = false;
+    for( const CXXMethodDecl* method : decl->methods())
+    {
+        if( !method->getDeclName().isIdentifier())
+            continue;
+        if( method->isStatic() || method->getAccess() != AS_public )
+            continue;
+        if( method->getName().startswith( "Visit" ))
+        {
+            if( method->getNumParams() == 1 )
+            {
+                VisitFunctionInfo visitInfo;
+                visitInfo.name = method->getName().str();
+                visitInfo.argument = method->getParamDecl( 0 )->getTypeSourceInfo()->getType().getAsString();
+                pluginInfo.visitFunctions.insert( move( visitInfo ));
+            }
+            else
+            {
+                cerr << "Unhandled Visit* function: " << pluginInfo.className << "::" << method->getName().str() << endl;
+                abort();
+            }
+        }
+        else if( method->getName().startswith( "Traverse" ))
+        {
+            if( method->getNumParams() == 1 )
+            {
+                TraverseFunctionInfo traverseInfo = findOrCreateTraverseFunctionInfo( pluginInfo, method->getName());
+                traverseInfo.argument = method->getParamDecl( 0 )->getTypeSourceInfo()->getType().getAsString();
+                pluginInfo.traverseFunctions.insert( move( traverseInfo ));
+            }
+            else
+            {
+                cerr << "Unhandled Traverse* function: " << pluginInfo.className << "::" << method->getName().str() << endl;
+                abort();
+            }
+        }
+        else if( method->getName().startswith( "PreTraverse" ))
+        {
+                TraverseFunctionInfo traverseInfo = findOrCreateTraverseFunctionInfo( pluginInfo, method->getName(). substr( 3 ));
+                traverseInfo.hasPre = true;
+                pluginInfo.traverseFunctions.insert( move( traverseInfo ));
+        }
+        else if( method->getName().startswith( "PostTraverse" ))
+        {
+                TraverseFunctionInfo traverseInfo = findOrCreateTraverseFunctionInfo( pluginInfo, method->getName().substr( 4 ));
+                traverseInfo.hasPost = true;
+                pluginInfo.traverseFunctions.insert( move( traverseInfo ));
+        }
+        else if( method->getName() == "shouldVisitTemplateInstantiations" )
+            pluginInfo.shouldVisitTemplateInstantiations = true;
+        else if( method->getName() == "shouldVisitImplicitCode" )
+            pluginInfo.shouldVisitImplicitCode = true;
+        else if( method->getName().startswith( "WalkUp" ))
+        {
+            cerr << "WalkUp function not supported for shared visitor: " << pluginInfo.className << "::" << method->getName().str() << endl;
+            abort();
+        }
+    }
+
+    if( pluginInfo.shouldVisitTemplateInstantiations && pluginInfo.shouldVisitImplicitCode )
+        plugins[ PluginVisitTemplatesImplicit ].push_back( move( pluginInfo ));
+    else if( pluginInfo.shouldVisitTemplateInstantiations )
+        plugins[ PluginVisitTemplates ].push_back( move( pluginInfo ));
+    else if( pluginInfo.shouldVisitImplicitCode )
+        plugins[ PluginVisitImplicit ].push_back( move( pluginInfo ));
+    else
+        plugins[ PluginBasic ].push_back( move( pluginInfo ));
+    return true;
+}
+
+
+class FindNamedClassConsumer
+    : public ASTConsumer
+{
+public:
+    virtual void HandleTranslationUnit(ASTContext& context) override
+    {
+        visitor.TraverseDecl( context.getTranslationUnitDecl());
+    }
+private:
+    CheckFileVisitor visitor;
+};
+
+class FindNamedClassAction
+    : public ASTFrontendAction
+    {
+public:
+    virtual unique_ptr<ASTConsumer> CreateASTConsumer( CompilerInstance&, StringRef ) override
+    {
+        return unique_ptr<ASTConsumer>( new FindNamedClassConsumer );
+    }
+};
+
+
+string readSourceFile( const char* filename )
+{
+    string contents;
+    ifstream stream( filename );
+    if( !stream )
+    {
+        cerr << "Failed to open: " << filename << endl;
+        exit( 1 );
+    }
+    string line;
+    bool hasIfdef = false;
+    while( getline( stream, line ))
+    {
+        // TODO add checks that it's e.g. not "#ifdef" ?
+        if( line.find( "#ifndef LO_CLANG_SHARED_PLUGINS" ) == 0 )
+            hasIfdef = true;
+        contents += line;
+        contents += '\n';
+    }
+    if( stream.eof() && hasIfdef )
+        return contents;
+    return "";
+}
+
+int main(int argc, char** argv)
+{
+    for( int i = 1; i < argc; ++ i )
+    {
+        string contents = readSourceFile(argv[i]);
+        if( contents.empty())
+            continue;
+#define STRINGIFY2(a) #a
+#define STRINGIFY(a) STRINGIFY2(a)
+        vector< string > args =
+        {
+            "-I" STRINGIFY(BUILDDIR) "/config_host", // plugin sources use e.g. config_global.h
+            "-I" STRINGIFY(CLANGDIR) "/include", // clang's headers
+            "-I" STRINGIFY(CLANGSYSINCLUDE), // clang system headers
+            "-std=c++11",
+            "-D__STDC_CONSTANT_MACROS", // Clang headers require these.
+            "-D__STDC_FORMAT_MACROS",
+            "-D__STDC_LIMIT_MACROS",
+        };
+        if( !clang::tooling::runToolOnCodeWithArgs( new FindNamedClassAction, contents, args, argv[ i ] ))
+        {
+            cerr << "Failed to analyze: " << argv[ i ] << endl;
+            return 2;
+        }
+    }
+    for( int type = Plugin_Begin; type < Plugin_End; ++type )
+    {
+        sort( plugins[ static_cast< PluginType >( type ) ].begin(), plugins[ static_cast< PluginType >( type ) ].end(),
+            []( const PluginInfo& l, const PluginInfo& r ) { return l.className < r.className; } );
+    }
+    generate();
+    return 0;
+}
diff --git a/compilerplugins/clang/sharedvisitor/sharedvisitor.cxx b/compilerplugins/clang/sharedvisitor/sharedvisitor.cxx
new file mode 100644
index 000000000000..5b72c329691d
--- /dev/null
+++ b/compilerplugins/clang/sharedvisitor/sharedvisitor.cxx
@@ -0,0 +1,964 @@
+// This file is autogenerated. Do not modify.
+// Generated by compilerplugins/clang/sharedvisitor/generator.cxx .
+
+#ifdef LO_CLANG_SHARED_PLUGINS
+
+#include <config_clang.h>
+
+#include <clang/AST/ASTContext.h>
+#include <clang/AST/RecursiveASTVisitor.h>
+
+#include "../plugin.hxx"
+
+#undef LO_CLANG_SHARED_PLUGINS // to get sources of individual plugins
+#include "../badstatics.cxx"
+#include "../blockblock.cxx"
+#include "../charrightshift.cxx"
+#include "../datamembershadow.cxx"
+#include "../dbgunhandledexception.cxx"
+#include "../derefnullptr.cxx"
+#include "../doubleconvert.cxx"
+#include "../empty.cxx"
+#include "../emptyif.cxx"
+#include "../externandnotdefined.cxx"
+#include "../externvar.cxx"
+#include "../inlinevisible.cxx"
+#include "../loopvartoosmall.cxx"
+#include "../privatebase.cxx"
+#include "../reservedid.cxx"
+#include "../simplifyconstruct.cxx"
+#include "../stringstatic.cxx"
+#include "../subtlezeroinit.cxx"
+#include "../unnecessaryoverride.cxx"
+#include "../unnecessaryparen.cxx"
+#include "../unreffun.cxx"
+#include "../unusedvariablecheck.cxx"
+#include "../weakobject.cxx"
+#include "../dyncastvisibility.cxx"
+#include "../vclwidgets.cxx"
+
+using namespace clang;
+using namespace llvm;
+
+namespace loplugin
+{
+
+class SharedRecursiveASTVisitorBasic
+    : public FilteringPlugin< SharedRecursiveASTVisitorBasic>
+{
+public:
+    explicit SharedRecursiveASTVisitorBasic(const InstantiationData& rData)
+        : FilteringPlugin(rData)
+        , badStatics( nullptr )
+        , blockBlock( nullptr )
+        , charRightShift( nullptr )
+        , dataMemberShadow( nullptr )
+        , dbgUnhandledException( nullptr )
+        , derefNullPtr( nullptr )
+        , doubleConvert( nullptr )
+        , empty( nullptr )
+        , emptyIf( nullptr )
+        , externAndNotDefined( nullptr )
+        , externVar( nullptr )
+        , inlineVisible( nullptr )
+        , loopVarTooSmall( nullptr )
+        , privateBase( nullptr )
+        , reservedId( nullptr )
+        , simplifyConstruct( nullptr )
+        , stringStatic( nullptr )
+        , subtleZeroInit( nullptr )
+        , unnecessaryOverride( nullptr )
+        , unnecessaryParen( nullptr )
+        , unrefFun( nullptr )
+        , unusedVariableCheck( nullptr )
+        , weakObject( nullptr )
+        {}
+    virtual bool preRun() override
+    {
+        if( badStatics && !badStatics->preRun())
+            badStatics = nullptr;
+        if( blockBlock && !blockBlock->preRun())
+            blockBlock = nullptr;
+        if( charRightShift && !charRightShift->preRun())
+            charRightShift = nullptr;
+        if( dataMemberShadow && !dataMemberShadow->preRun())
+            dataMemberShadow = nullptr;
+        if( dbgUnhandledException && !dbgUnhandledException->preRun())
+            dbgUnhandledException = nullptr;
+        if( derefNullPtr && !derefNullPtr->preRun())
+            derefNullPtr = nullptr;
+        if( doubleConvert && !doubleConvert->preRun())
+            doubleConvert = nullptr;
+        if( empty && !empty->preRun())
+            empty = nullptr;
+        if( emptyIf && !emptyIf->preRun())
+            emptyIf = nullptr;
+        if( externAndNotDefined && !externAndNotDefined->preRun())
+            externAndNotDefined = nullptr;
+        if( externVar && !externVar->preRun())
+            externVar = nullptr;
+        if( inlineVisible && !inlineVisible->preRun())
+            inlineVisible = nullptr;
+        if( loopVarTooSmall && !loopVarTooSmall->preRun())
+            loopVarTooSmall = nullptr;
+        if( privateBase && !privateBase->preRun())
+            privateBase = nullptr;
+        if( reservedId && !reservedId->preRun())
+            reservedId = nullptr;
+        if( simplifyConstruct && !simplifyConstruct->preRun())
+            simplifyConstruct = nullptr;
+        if( stringStatic && !stringStatic->preRun())
+            stringStatic = nullptr;
+        if( subtleZeroInit && !subtleZeroInit->preRun())
+            subtleZeroInit = nullptr;
+        if( unnecessaryOverride && !unnecessaryOverride->preRun())
+            unnecessaryOverride = nullptr;
+        if( unnecessaryParen && !unnecessaryParen->preRun())
+            unnecessaryParen = nullptr;
+        if( unrefFun && !unrefFun->preRun())
+            unrefFun = nullptr;
+        if( unusedVariableCheck && !unusedVariableCheck->preRun())
+            unusedVariableCheck = nullptr;
+        if( weakObject && !weakObject->preRun())
+            weakObject = nullptr;
+        return anyPluginActive();
+    }
+    virtual void postRun() override
+    {
+        if( badStatics )
+            badStatics->postRun();
+        if( blockBlock )
+            blockBlock->postRun();
+        if( charRightShift )
+            charRightShift->postRun();
+        if( dataMemberShadow )
+            dataMemberShadow->postRun();
+        if( dbgUnhandledException )
+            dbgUnhandledException->postRun();
+        if( derefNullPtr )
+            derefNullPtr->postRun();
+        if( doubleConvert )
+            doubleConvert->postRun();
+        if( empty )
+            empty->postRun();
+        if( emptyIf )
+            emptyIf->postRun();
+        if( externAndNotDefined )
+            externAndNotDefined->postRun();
+        if( externVar )
+            externVar->postRun();
+        if( inlineVisible )
+            inlineVisible->postRun();
+        if( loopVarTooSmall )
+            loopVarTooSmall->postRun();
+        if( privateBase )
+            privateBase->postRun();
+        if( reservedId )
+            reservedId->postRun();
+        if( simplifyConstruct )
+            simplifyConstruct->postRun();
+        if( stringStatic )
+            stringStatic->postRun();
+        if( subtleZeroInit )
+            subtleZeroInit->postRun();
+        if( unnecessaryOverride )
+            unnecessaryOverride->postRun();
+        if( unnecessaryParen )
+            unnecessaryParen->postRun();
+        if( unrefFun )
+            unrefFun->postRun();
+        if( unusedVariableCheck )
+            unusedVariableCheck->postRun();
+        if( weakObject )
+            weakObject->postRun();
+    }
+    virtual void run() override {
+        if (preRun()) {
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+            postRun();
+        }
+    }
+    enum { isSharedPlugin = true };
+    virtual bool setSharedPlugin( Plugin* plugin, const char* name ) override
+    {
+        if( strcmp( name, "badstatics" ) == 0 )
+            badStatics = static_cast< BadStatics* >( plugin );
+        else if( strcmp( name, "blockblock" ) == 0 )
+            blockBlock = static_cast< BlockBlock* >( plugin );
+        else if( strcmp( name, "charrightshift" ) == 0 )
+            charRightShift = static_cast< CharRightShift* >( plugin );
+        else if( strcmp( name, "datamembershadow" ) == 0 )
+            dataMemberShadow = static_cast< DataMemberShadow* >( plugin );
+        else if( strcmp( name, "dbgunhandledexception" ) == 0 )
+            dbgUnhandledException = static_cast< DbgUnhandledException* >( plugin );
+        else if( strcmp( name, "derefnullptr" ) == 0 )
+            derefNullPtr = static_cast< DerefNullPtr* >( plugin );
+        else if( strcmp( name, "doubleconvert" ) == 0 )
+            doubleConvert = static_cast< DoubleConvert* >( plugin );
+        else if( strcmp( name, "empty" ) == 0 )
+            empty = static_cast< Empty* >( plugin );
+        else if( strcmp( name, "emptyif" ) == 0 )
+            emptyIf = static_cast< EmptyIf* >( plugin );
+        else if( strcmp( name, "externandnotdefined" ) == 0 )
+            externAndNotDefined = static_cast< ExternAndNotDefined* >( plugin );
+        else if( strcmp( name, "externvar" ) == 0 )
+            externVar = static_cast< ExternVar* >( plugin );
+        else if( strcmp( name, "inlinevisible" ) == 0 )
+            inlineVisible = static_cast< InlineVisible* >( plugin );
+        else if( strcmp( name, "loopvartoosmall" ) == 0 )
+            loopVarTooSmall = static_cast< LoopVarTooSmall* >( plugin );
+        else if( strcmp( name, "privatebase" ) == 0 )
+            privateBase = static_cast< PrivateBase* >( plugin );
+        else if( strcmp( name, "reservedid" ) == 0 )
+            reservedId = static_cast< ReservedId* >( plugin );
+        else if( strcmp( name, "simplifyconstruct" ) == 0 )
+            simplifyConstruct = static_cast< SimplifyConstruct* >( plugin );
+        else if( strcmp( name, "stringstatic" ) == 0 )
+            stringStatic = static_cast< StringStatic* >( plugin );
+        else if( strcmp( name, "subtlezeroinit" ) == 0 )
+            subtleZeroInit = static_cast< SubtleZeroInit* >( plugin );
+        else if( strcmp( name, "unnecessaryoverride" ) == 0 )
+            unnecessaryOverride = static_cast< UnnecessaryOverride* >( plugin );
+        else if( strcmp( name, "unnecessaryparen" ) == 0 )
+            unnecessaryParen = static_cast< UnnecessaryParen* >( plugin );
+        else if( strcmp( name, "unreffun" ) == 0 )
+            unrefFun = static_cast< UnrefFun* >( plugin );
+        else if( strcmp( name, "unusedvariablecheck" ) == 0 )
+            unusedVariableCheck = static_cast< UnusedVariableCheck* >( plugin );
+        else if( strcmp( name, "weakobject" ) == 0 )
+            weakObject = static_cast< WeakObject* >( plugin );
+        else
+            return false;
+        return true;
+    }
+    bool VisitBinEQ(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( empty != nullptr )
+        {
+            if( !empty->VisitBinEQ( arg ))
+                empty = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitBinGE(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( empty != nullptr )
+        {
+            if( !empty->VisitBinGE( arg ))
+                empty = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitBinGT(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( empty != nullptr )
+        {
+            if( !empty->VisitBinGT( arg ))
+                empty = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitBinLE(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( empty != nullptr )
+        {
+            if( !empty->VisitBinLE( arg ))
+                empty = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitBinLT(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( empty != nullptr )
+        {
+            if( !empty->VisitBinLT( arg ))
+                empty = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitBinNE(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( empty != nullptr )
+        {
+            if( !empty->VisitBinNE( arg ))
+                empty = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitBinShr(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( charRightShift != nullptr )
+        {
+            if( !charRightShift->VisitBinShr( arg ))
+                charRightShift = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitBinaryConditionalOperator(const class clang::BinaryConditionalOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitBinaryConditionalOperator( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXConstructExpr(const class clang::CXXConstructExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( simplifyConstruct != nullptr )
+        {
+            if( !simplifyConstruct->VisitCXXConstructExpr( arg ))
+                simplifyConstruct = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXDeleteExpr(const class clang::CXXDeleteExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitCXXDeleteExpr( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXMethodDecl(const class clang::CXXMethodDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryOverride != nullptr )
+        {
+            if( !unnecessaryOverride->VisitCXXMethodDecl( arg ))
+                unnecessaryOverride = nullptr;
+        }
+        if( weakObject != nullptr )
+        {
+            if( !weakObject->VisitCXXMethodDecl( arg ))
+                weakObject = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXNewExpr(const class clang::CXXNewExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( subtleZeroInit != nullptr )
+        {
+            if( !subtleZeroInit->VisitCXXNewExpr( arg ))
+                subtleZeroInit = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXOperatorCallExpr(const class clang::CXXOperatorCallExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitCXXOperatorCallExpr( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXRecordDecl(const class clang::CXXRecordDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( privateBase != nullptr )
+        {
+            if( !privateBase->VisitCXXRecordDecl( arg ))
+                privateBase = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCallExpr(const class clang::CallExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( dbgUnhandledException != nullptr )
+        {
+            if( !dbgUnhandledException->VisitCallExpr( arg ))
+                dbgUnhandledException = nullptr;
+        }
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitCallExpr( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCaseStmt(const class clang::CaseStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitCaseStmt( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCompoundStmt(const class clang::CompoundStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( blockBlock != nullptr )
+        {
+            if( !blockBlock->VisitCompoundStmt( arg ))
+                blockBlock = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitConditionalOperator(const class clang::ConditionalOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitConditionalOperator( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitDoStmt(const class clang::DoStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( loopVarTooSmall != nullptr )
+        {
+            if( !loopVarTooSmall->VisitDoStmt( arg ))
+                loopVarTooSmall = nullptr;
+        }
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitDoStmt( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitFieldDecl(const class clang::FieldDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( dataMemberShadow != nullptr )
+        {
+            if( !dataMemberShadow->VisitFieldDecl( arg ))
+                dataMemberShadow = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitForStmt(const class clang::ForStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( loopVarTooSmall != nullptr )
+        {
+            if( !loopVarTooSmall->VisitForStmt( arg ))
+                loopVarTooSmall = nullptr;
+        }
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitForStmt( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitFunctionDecl(const class clang::FunctionDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( externAndNotDefined != nullptr )
+        {
+            if( !externAndNotDefined->VisitFunctionDecl( arg ))
+                externAndNotDefined = nullptr;
+        }
+        if( inlineVisible != nullptr )
+        {
+            if( !inlineVisible->VisitFunctionDecl( arg ))
+                inlineVisible = nullptr;
+        }
+        if( unrefFun != nullptr )
+        {
+            if( !unrefFun->VisitFunctionDecl( arg ))
+                unrefFun = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitIfStmt(const class clang::IfStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( emptyIf != nullptr )
+        {
+            if( !emptyIf->VisitIfStmt( arg ))
+                emptyIf = nullptr;
+        }
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitIfStmt( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitMaterializeTemporaryExpr(const class clang::MaterializeTemporaryExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( doubleConvert != nullptr )
+        {
+            if( !doubleConvert->VisitMaterializeTemporaryExpr( arg ))
+                doubleConvert = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitMemberExpr(const class clang::MemberExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitMemberExpr( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitNamedDecl(const class clang::NamedDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( reservedId != nullptr )
+        {
+            if( !reservedId->VisitNamedDecl( arg ))
+                reservedId = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitParenExpr(const class clang::ParenExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitParenExpr( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitReturnStmt(const class clang::ReturnStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( stringStatic != nullptr )
+        {
+            if( !stringStatic->VisitReturnStmt( arg ))
+                stringStatic = nullptr;
+        }
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitReturnStmt( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitSwitchStmt(const class clang::SwitchStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitSwitchStmt( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitUnaryDeref(const class clang::UnaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( derefNullPtr != nullptr )
+        {
+            if( !derefNullPtr->VisitUnaryDeref( arg ))
+                derefNullPtr = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitUnaryExprOrTypeTraitExpr(const class clang::UnaryExprOrTypeTraitExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitUnaryExprOrTypeTraitExpr( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitVarDecl(const class clang::VarDecl *const arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( badStatics != nullptr )
+        {
+            if( !badStatics->VisitVarDecl( arg ))
+                badStatics = nullptr;
+        }
+        if( externVar != nullptr )
+        {
+            if( !externVar->VisitVarDecl( arg ))
+                externVar = nullptr;
+        }
+        if( stringStatic != nullptr )
+        {
+            if( !stringStatic->VisitVarDecl( arg ))
+                stringStatic = nullptr;
+        }
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitVarDecl( arg ))
+                unnecessaryParen = nullptr;
+        }
+        if( unusedVariableCheck != nullptr )
+        {
+            if( !unusedVariableCheck->VisitVarDecl( arg ))
+                unusedVariableCheck = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitWhileStmt(const class clang::WhileStmt * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( loopVarTooSmall != nullptr )
+        {
+            if( !loopVarTooSmall->VisitWhileStmt( arg ))
+                loopVarTooSmall = nullptr;
+        }
+        if( unnecessaryParen != nullptr )
+        {
+            if( !unnecessaryParen->VisitWhileStmt( arg ))
+                unnecessaryParen = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool TraverseCXXBindTemporaryExpr(class clang::CXXBindTemporaryExpr * arg)
+    {
+        SimplifyConstruct* saveSimplifyConstruct = simplifyConstruct;
+        if( simplifyConstruct != nullptr )
+        {
+            if( !simplifyConstruct->PreTraverseCXXBindTemporaryExpr( arg ))
+                simplifyConstruct = nullptr;
+        }
+        bool ret = RecursiveASTVisitor::TraverseCXXBindTemporaryExpr( arg );
+        simplifyConstruct = saveSimplifyConstruct;
+        return ret;
+    }
+    bool TraverseCXXCatchStmt(class clang::CXXCatchStmt * arg)
+    {
+        DbgUnhandledException* saveDbgUnhandledException = dbgUnhandledException;
+        if( dbgUnhandledException != nullptr )
+        {
+            if( !dbgUnhandledException->PreTraverseCXXCatchStmt( arg ))
+                dbgUnhandledException = nullptr;
+        }
+        bool ret = RecursiveASTVisitor::TraverseCXXCatchStmt( arg );
+        if( dbgUnhandledException != nullptr )
+        {
+            if( !dbgUnhandledException->PostTraverseCXXCatchStmt( arg, ret ))
+                saveDbgUnhandledException = nullptr;
+        }
+        dbgUnhandledException = saveDbgUnhandledException;
+        return ret;
+    }
+    bool TraverseFriendDecl(class clang::FriendDecl * arg)
+    {
+        UnrefFun* saveUnrefFun = unrefFun;
+        if( unrefFun != nullptr )
+        {
+            if( !unrefFun->PreTraverseFriendDecl( arg ))
+                unrefFun = nullptr;
+        }
+        bool ret = RecursiveASTVisitor::TraverseFriendDecl( arg );
+        if( unrefFun != nullptr )
+        {
+            if( !unrefFun->PostTraverseFriendDecl( arg, ret ))
+                saveUnrefFun = nullptr;
+        }
+        unrefFun = saveUnrefFun;
+        return ret;
+    }
+    bool TraverseInitListExpr(class clang::InitListExpr * arg)
+    {
+        SimplifyConstruct* saveSimplifyConstruct = simplifyConstruct;
+        if( simplifyConstruct != nullptr )
+        {
+            if( !simplifyConstruct->PreTraverseInitListExpr( arg ))
+                simplifyConstruct = nullptr;
+        }
+        bool ret = RecursiveASTVisitor::TraverseInitListExpr( arg );
+        simplifyConstruct = saveSimplifyConstruct;
+        return ret;
+    }
+    bool TraverseReturnStmt(class clang::ReturnStmt * arg)
+    {
+        SimplifyConstruct* saveSimplifyConstruct = simplifyConstruct;
+        if( simplifyConstruct != nullptr )
+        {
+            if( !simplifyConstruct->PreTraverseReturnStmt( arg ))
+                simplifyConstruct = nullptr;
+        }
+        bool ret = RecursiveASTVisitor::TraverseReturnStmt( arg );
+        simplifyConstruct = saveSimplifyConstruct;
+        return ret;
+    }
+private:
+    bool anyPluginActive() const
+    {
+        return badStatics != nullptr
+            || blockBlock != nullptr
+            || charRightShift != nullptr
+            || dataMemberShadow != nullptr
+            || dbgUnhandledException != nullptr
+            || derefNullPtr != nullptr
+            || doubleConvert != nullptr
+            || empty != nullptr
+            || emptyIf != nullptr
+            || externAndNotDefined != nullptr
+            || externVar != nullptr
+            || inlineVisible != nullptr
+            || loopVarTooSmall != nullptr
+            || privateBase != nullptr
+            || reservedId != nullptr
+            || simplifyConstruct != nullptr
+            || stringStatic != nullptr
+            || subtleZeroInit != nullptr
+            || unnecessaryOverride != nullptr
+            || unnecessaryParen != nullptr
+            || unrefFun != nullptr
+            || unusedVariableCheck != nullptr
+            || weakObject != nullptr;
+    }
+    BadStatics* badStatics;
+    BlockBlock* blockBlock;
+    CharRightShift* charRightShift;
+    DataMemberShadow* dataMemberShadow;
+    DbgUnhandledException* dbgUnhandledException;
+    DerefNullPtr* derefNullPtr;
+    DoubleConvert* doubleConvert;
+    Empty* empty;
+    EmptyIf* emptyIf;
+    ExternAndNotDefined* externAndNotDefined;
+    ExternVar* externVar;
+    InlineVisible* inlineVisible;
+    LoopVarTooSmall* loopVarTooSmall;
+    PrivateBase* privateBase;
+    ReservedId* reservedId;
+    SimplifyConstruct* simplifyConstruct;
+    StringStatic* stringStatic;
+    SubtleZeroInit* subtleZeroInit;
+    UnnecessaryOverride* unnecessaryOverride;
+    UnnecessaryParen* unnecessaryParen;
+    UnrefFun* unrefFun;
+    UnusedVariableCheck* unusedVariableCheck;
+    WeakObject* weakObject;
+};
+
+loplugin::Plugin::Registration< SharedRecursiveASTVisitorBasic > registrationBasic("sharedvisitorBasic");
+
+
+class SharedRecursiveASTVisitorVisitTemplates
+    : public FilteringPlugin< SharedRecursiveASTVisitorVisitTemplates>
+{
+public:
+    explicit SharedRecursiveASTVisitorVisitTemplates(const InstantiationData& rData)
+        : FilteringPlugin(rData)
+        , dynCastVisibility( nullptr )
+        , vCLWidgets( nullptr )
+        {}
+    virtual bool preRun() override
+    {
+        if( dynCastVisibility && !dynCastVisibility->preRun())
+            dynCastVisibility = nullptr;
+        if( vCLWidgets && !vCLWidgets->preRun())
+            vCLWidgets = nullptr;
+        return anyPluginActive();
+    }
+    virtual void postRun() override
+    {
+        if( dynCastVisibility )
+            dynCastVisibility->postRun();
+        if( vCLWidgets )
+            vCLWidgets->postRun();
+    }
+    virtual void run() override {
+        if (preRun()) {
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+            postRun();
+        }
+    }
+    enum { isSharedPlugin = true };
+    virtual bool setSharedPlugin( Plugin* plugin, const char* name ) override
+    {
+        if( strcmp( name, "dyncastvisibility" ) == 0 )
+            dynCastVisibility = static_cast< DynCastVisibility* >( plugin );
+        else if( strcmp( name, "vclwidgets" ) == 0 )
+            vCLWidgets = static_cast< VCLWidgets* >( plugin );
+        else
+            return false;
+        return true;
+    }
+bool shouldVisitTemplateInstantiations() const { return true; }
+    bool VisitBinaryOperator(const class clang::BinaryOperator * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitBinaryOperator( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXConstructExpr(const class clang::CXXConstructExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitCXXConstructExpr( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXDeleteExpr(const class clang::CXXDeleteExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitCXXDeleteExpr( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXDestructorDecl(const class clang::CXXDestructorDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitCXXDestructorDecl( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCXXDynamicCastExpr(const class clang::CXXDynamicCastExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( dynCastVisibility != nullptr )
+        {
+            if( !dynCastVisibility->VisitCXXDynamicCastExpr( arg ))
+                dynCastVisibility = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitCallExpr(const class clang::CallExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitCallExpr( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitDeclRefExpr(const class clang::DeclRefExpr * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitDeclRefExpr( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitFieldDecl(const class clang::FieldDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitFieldDecl( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitFunctionDecl(const class clang::FunctionDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitFunctionDecl( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitParmVarDecl(const class clang::ParmVarDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitParmVarDecl( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+    bool VisitVarDecl(const class clang::VarDecl * arg)
+    {
+        if( ignoreLocation( arg ))
+            return true;
+        if( vCLWidgets != nullptr )
+        {
+            if( !vCLWidgets->VisitVarDecl( arg ))
+                vCLWidgets = nullptr;
+        }
+        return anyPluginActive();
+    }
+private:
+    bool anyPluginActive() const
+    {
+        return dynCastVisibility != nullptr
+            || vCLWidgets != nullptr;
+    }
+    DynCastVisibility* dynCastVisibility;
+    VCLWidgets* vCLWidgets;
+};
+
+loplugin::Plugin::Registration< SharedRecursiveASTVisitorVisitTemplates > registrationVisitTemplates("sharedvisitorVisitTemplates");
+
+} // namespace loplugin
+
+#endif // LO_CLANG_SHARED_PLUGINS
diff --git a/compilerplugins/clang/simplifyconstruct.cxx b/compilerplugins/clang/simplifyconstruct.cxx
index b48764302eae..652a980cec6a 100644
--- a/compilerplugins/clang/simplifyconstruct.cxx
+++ b/compilerplugins/clang/simplifyconstruct.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <memory>
 #include <cassert>
 #include <string>
@@ -34,6 +36,10 @@ public:
     bool TraverseReturnStmt(ReturnStmt*) { return true; }
     bool TraverseInitListExpr(InitListExpr*) { return true; }
     bool TraverseCXXBindTemporaryExpr(CXXBindTemporaryExpr*) { return true; }
+    // ignore them for the shared visitor too
+    bool PreTraverseReturnStmt(ReturnStmt*) { return false; }
+    bool PreTraverseInitListExpr(InitListExpr*) { return false; }
+    bool PreTraverseCXXBindTemporaryExpr(CXXBindTemporaryExpr*) { return false; }
 };
 
 bool SimplifyConstruct::VisitCXXConstructExpr(CXXConstructExpr const* constructExpr)
@@ -63,7 +69,9 @@ bool SimplifyConstruct::VisitCXXConstructExpr(CXXConstructExpr const* constructE
     return true;
 }
 
-loplugin::Plugin::Registration<SimplifyConstruct> X("simplifyconstruct", true);
+loplugin::Plugin::Registration<SimplifyConstruct> simplifyconstruct("simplifyconstruct", true);
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/store/tutorial/tutorial1.cxx b/compilerplugins/clang/store/tutorial/tutorial1.cxx
index 0b73431fbbad..9f7c97fb776f 100644
--- a/compilerplugins/clang/store/tutorial/tutorial1.cxx
+++ b/compilerplugins/clang/store/tutorial/tutorial1.cxx
@@ -61,7 +61,7 @@ bool Tutorial1::VisitReturnStmt( const ReturnStmt* returnstmt )
     }
 
 // Register the plugin action with the LO plugin handling.
-static Plugin::Registration< Tutorial1 > X( "tutorial1" );
+static Plugin::Registration< Tutorial1 > tutorial1( "tutorial1" );
 
 } // namespace
 
diff --git a/compilerplugins/clang/store/tutorial/tutorial2.cxx b/compilerplugins/clang/store/tutorial/tutorial2.cxx
index 8ef338c6d5f8..49aaaa63183f 100644
--- a/compilerplugins/clang/store/tutorial/tutorial2.cxx
+++ b/compilerplugins/clang/store/tutorial/tutorial2.cxx
@@ -88,7 +88,7 @@ bool Tutorial2::isReturnFalse( const Stmt* stmt )
     }
 
 // Register the plugin action with the LO plugin handling.
-static Plugin::Registration< Tutorial2 > X( "tutorial2" );
+static Plugin::Registration< Tutorial2 > tutorial2( "tutorial2" );
 
 } // namespace
 
diff --git a/compilerplugins/clang/store/tutorial/tutorial3.cxx b/compilerplugins/clang/store/tutorial/tutorial3.cxx
index e48118611eb7..33a1249a3400 100644
--- a/compilerplugins/clang/store/tutorial/tutorial3.cxx
+++ b/compilerplugins/clang/store/tutorial/tutorial3.cxx
@@ -70,7 +70,7 @@ void Tutorial3::modifyReturnFalse( const Stmt* stmt )
     }
 
 // Register the plugin action with the LO plugin handling.
-static Plugin::Registration< Tutorial3 > X( "tutorial3" );
+static Plugin::Registration< Tutorial3 > tutorial3( "tutorial3" );
 
 } // namespace
 
diff --git a/compilerplugins/clang/stringstatic.cxx b/compilerplugins/clang/stringstatic.cxx
index 1a46fdd3dee8..a923da405f25 100644
--- a/compilerplugins/clang/stringstatic.cxx
+++ b/compilerplugins/clang/stringstatic.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <set>
 
 #include "check.hxx"
@@ -30,6 +32,8 @@ public:
         FilteringPlugin(rData) {}
 
     void run() override;
+    bool preRun() override;
+    void postRun() override;
     bool VisitVarDecl(VarDecl const*);
     bool VisitReturnStmt(ReturnStmt const*);
 private:
@@ -39,16 +43,25 @@ private:
 
 void StringStatic::run()
 {
+    if( preRun())
+        if( TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()))
+            postRun();
+}
+
+bool StringStatic::preRun()
+{
     StringRef fn(handler.getMainFileName());
     // passing around pointers to global OUString
     if (loplugin::hasPathnamePrefix(fn, SRCDIR "/filter/source/svg/"))
-         return;
+         return false;
     // has a mix of literals and refs to external OUStrings
     if (loplugin::isSamePathname(fn, SRCDIR "/ucb/source/ucp/webdav-neon/ContentProperties.cxx"))
-         return;
-
-    TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+         return false;
+    return true;
+}
 
+void StringStatic::postRun()
+{
     for (auto const & pVarDecl : excludeVars) {
         potentialVars.erase(pVarDecl);
     }
@@ -128,8 +141,10 @@ bool StringStatic::VisitReturnStmt(ReturnStmt const * returnStmt)
     return true;
 }
 
-loplugin::Plugin::Registration<StringStatic> X("stringstatic");
+loplugin::Plugin::Registration<StringStatic> stringstatic("stringstatic");
 
 } // namespace
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/subtlezeroinit.cxx b/compilerplugins/clang/subtlezeroinit.cxx
index aa0a3dd72d13..b1b91c8477d5 100644
--- a/compilerplugins/clang/subtlezeroinit.cxx
+++ b/compilerplugins/clang/subtlezeroinit.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "plugin.hxx"
 
 // Find occurrences of 'new T()' where the instance is zero-initialized upfront
@@ -45,16 +47,21 @@ public:
         return true;
     }
 
-private:
-    void run() override {
-        if (compiler.getLangOpts().CPlusPlus) {
+    virtual bool preRun() override {
+        return compiler.getLangOpts().CPlusPlus;
+    }
+
+    virtual void run() override {
+        if (preRun()) {
             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
         }
     }
 };
 
-static loplugin::Plugin::Registration<SubtleZeroInit> reg("subtlezeroinit");
+static loplugin::Plugin::Registration<SubtleZeroInit> subtlezeroinit("subtlezeroinit");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/unnecessaryoverride.cxx b/compilerplugins/clang/unnecessaryoverride.cxx
index 00a1f7686c21..4d4cee322751 100644
--- a/compilerplugins/clang/unnecessaryoverride.cxx
+++ b/compilerplugins/clang/unnecessaryoverride.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
 #include <string>
 #include <iostream>
@@ -69,31 +71,36 @@ class UnnecessaryOverride:
 public:
     explicit UnnecessaryOverride(loplugin::InstantiationData const & data): FilteringPlugin(data) {}
 
-    virtual void run() override
+    virtual bool preRun() override
     {
         // ignore some files with problematic macros
         StringRef fn(handler.getMainFileName());
         if (loplugin::isSamePathname(fn, SRCDIR "/sd/source/ui/framework/factories/ChildWindowPane.cxx"))
-             return;
+            return false;
         if (loplugin::isSamePathname(fn, SRCDIR "/forms/source/component/Date.cxx"))
-             return;
+            return false;
         if (loplugin::isSamePathname(fn, SRCDIR "/forms/source/component/Time.cxx"))
-            return;
+            return false;
         if (loplugin::isSamePathname(fn, SRCDIR "/svx/source/dialog/hyperdlg.cxx"))
-            return;
+            return false;
         if (loplugin::isSamePathname(fn, SRCDIR "/svx/source/dialog/rubydialog.cxx"))
-            return;
+            return false;
         if (loplugin::hasPathnamePrefix(fn, SRCDIR "/canvas/"))
-            return;
+            return false;
         if (loplugin::isSamePathname(fn, SRCDIR "/sc/source/ui/view/spelldialog.cxx"))
-            return;
+            return false;
         if (loplugin::isSamePathname(fn, SRCDIR "/sd/source/ui/dlg/SpellDialogChildWindow.cxx"))
-            return;
+            return false;
         // HAVE_ODBC_ADMINISTRATION
         if (loplugin::isSamePathname(fn, SRCDIR "/dbaccess/source/ui/dlg/dsselect.cxx"))
-            return;
+            return false;
+        return true;
+    }
 
-        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+    virtual void run() override
+    {
+        if( preRun())
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
     }
 
     bool VisitCXXMethodDecl(const CXXMethodDecl *);
@@ -515,8 +522,10 @@ CXXMemberCallExpr const * UnnecessaryOverride::extractCallExpr(Expr const *retur
     return dyn_cast<CXXMemberCallExpr>(returnExpr->IgnoreParenImpCasts());
 }
 
-loplugin::Plugin::Registration< UnnecessaryOverride > X("unnecessaryoverride", true);
+loplugin::Plugin::Registration< UnnecessaryOverride > unnecessaryoverride("unnecessaryoverride", true);
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/unnecessaryparen.cxx b/compilerplugins/clang/unnecessaryparen.cxx
index 119ee98e13a5..9fb8fb85aa82 100644
--- a/compilerplugins/clang/unnecessaryparen.cxx
+++ b/compilerplugins/clang/unnecessaryparen.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
 #include <string>
 #include <iostream>
@@ -73,16 +75,20 @@ public:
     explicit UnnecessaryParen(loplugin::InstantiationData const & data):
         FilteringRewritePlugin(data) {}
 
-    virtual void run() override
+    virtual bool preRun() override
     {
         StringRef fn(handler.getMainFileName());
         // fixing this, makes the source in the .y files look horrible
         if (loplugin::isSamePathname(fn, WORKDIR "/YaccTarget/unoidl/source/sourceprovider-parser.cxx"))
-             return;
+            return false;
         if (loplugin::isSamePathname(fn, WORKDIR "/YaccTarget/idlc/source/parser.cxx"))
-             return;
-
-        TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+            return false;
+        return true;
+    }
+    virtual void run() override
+    {
+        if( preRun())
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
     }
 
     bool VisitParenExpr(const ParenExpr *);
@@ -626,8 +632,10 @@ bool UnnecessaryParen::removeParens(ParenExpr const * expr) {
     return true;
 }
 
-loplugin::Plugin::Registration< UnnecessaryParen > X("unnecessaryparen", true);
+loplugin::Plugin::Registration< UnnecessaryParen > unnecessaryparen("unnecessaryparen", true);
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/unreffun.cxx b/compilerplugins/clang/unreffun.cxx
index 04c4e9f95dc1..e5ea7f34ee38 100644
--- a/compilerplugins/clang/unreffun.cxx
+++ b/compilerplugins/clang/unreffun.cxx
@@ -7,7 +7,10 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <cassert>
+#include <stack>
 #include <string>
 
 #include "clang/AST/Attr.h"
@@ -71,18 +74,25 @@ public:
     void run() override
     { TraverseDecl(compiler.getASTContext().getTranslationUnitDecl()); }
 
+    bool PreTraverseFriendDecl(FriendDecl * decl) {
+        friendFunction.push( dyn_cast_or_null<FunctionDecl>(decl->getFriendDecl()));
+        return true;
+    }
+    bool PostTraverseFriendDecl(FriendDecl *, bool ) {
+        friendFunction.pop();
+        return true;
+    }
     bool TraverseFriendDecl(FriendDecl * decl) {
-        auto const old = friendFunction_;
-        friendFunction_ = dyn_cast_or_null<FunctionDecl>(decl->getFriendDecl());
+        PreTraverseFriendDecl(decl);
         auto const ret = RecursiveASTVisitor::TraverseFriendDecl(decl);
-        friendFunction_ = old;
+        PostTraverseFriendDecl(decl, ret);
         return ret;
     }
 
     bool VisitFunctionDecl(FunctionDecl const * decl);
 
 private:
-    FunctionDecl const * friendFunction_ = nullptr;
+    std::stack<FunctionDecl const *> friendFunction;
 };
 
 bool UnrefFun::VisitFunctionDecl(FunctionDecl const * decl) {
@@ -98,7 +108,7 @@ bool UnrefFun::VisitFunctionDecl(FunctionDecl const * decl) {
     {
         return true;
     }
-    if (decl == friendFunction_) {
+    if (!friendFunction.empty() && decl == friendFunction.top()) {
         if (auto const lex = dyn_cast<CXXRecordDecl>(decl->getLexicalDeclContext())) {
             if (lex->isDependentContext()) {
                 return true;
@@ -200,8 +210,10 @@ bool UnrefFun::VisitFunctionDecl(FunctionDecl const * decl) {
     return true;
 }
 
-loplugin::Plugin::Registration<UnrefFun> X("unreffun");
+loplugin::Plugin::Registration<UnrefFun> unreffun("unreffun");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/unusedvariablecheck.cxx b/compilerplugins/clang/unusedvariablecheck.cxx
index 8200ae8fc3b1..25af5438b465 100644
--- a/compilerplugins/clang/unusedvariablecheck.cxx
+++ b/compilerplugins/clang/unusedvariablecheck.cxx
@@ -9,6 +9,8 @@
  *
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <config_global.h>
 
 #include "compat.hxx"
@@ -72,8 +74,10 @@ bool UnusedVariableCheck::VisitVarDecl( const VarDecl* var )
     return true;
     }
 
-static Plugin::Registration< UnusedVariableCheck > X( "unusedvariablecheck" );
+static Plugin::Registration< UnusedVariableCheck > unusedvariablecheck( "unusedvariablecheck" );
 
 } // namespace
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/vclwidgets.cxx b/compilerplugins/clang/vclwidgets.cxx
index 8f625f5cdfdf..4c699bc5a77b 100644
--- a/compilerplugins/clang/vclwidgets.cxx
+++ b/compilerplugins/clang/vclwidgets.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include <memory>
 #include <string>
 #include <iostream>
@@ -859,8 +861,10 @@ bool VCLWidgets::VisitCXXConstructExpr( const CXXConstructExpr* constructExpr )
     return true;
 }
 
-loplugin::Plugin::Registration< VCLWidgets > X("vclwidgets");
+loplugin::Plugin::Registration< VCLWidgets > vclwidgets("vclwidgets");
 
 }
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/weakobject.cxx b/compilerplugins/clang/weakobject.cxx
index 1f801d6acdd2..afa652befc1a 100644
--- a/compilerplugins/clang/weakobject.cxx
+++ b/compilerplugins/clang/weakobject.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#ifndef LO_CLANG_SHARED_PLUGINS
+
 #include "check.hxx"
 #include "plugin.hxx"
 
@@ -26,8 +28,11 @@ public:
     explicit WeakObject(loplugin::InstantiationData const& rData): FilteringPlugin(rData)
     {}
 
+    virtual bool preRun() override {
+        return compiler.getLangOpts().CPlusPlus; // no OWeakObject in C
+    }
     void run() override {
-        if (compiler.getLangOpts().CPlusPlus) { // no OWeakObject in C
+        if( preRun()) {
             TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
         }
     }
@@ -153,8 +158,10 @@ public:
 
 };
 
-loplugin::Plugin::Registration<WeakObject> X("weakobject");
+loplugin::Plugin::Registration<WeakObject> weakobject("weakobject");
 
 } // namespace
 
+#endif // LO_CLANG_SHARED_PLUGINS
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/solenv/clang-format/blacklist b/solenv/clang-format/blacklist
index 66bfbb85d581..6b3f4aecd914 100644
--- a/solenv/clang-format/blacklist
+++ b/solenv/clang-format/blacklist
@@ -1753,6 +1753,8 @@ compilerplugins/clang/sallogareas.cxx
 compilerplugins/clang/sallogareas.hxx
 compilerplugins/clang/salunicodeliteral.cxx
 compilerplugins/clang/sfxpoolitem.cxx
+compilerplugins/clang/sharedvisitor/generator.cxx
+compilerplugins/clang/sharedvisitor/sharedvisitor.cxx
 compilerplugins/clang/simplifybool.cxx
 compilerplugins/clang/singlevalfields.cxx
 compilerplugins/clang/staticaccess.cxx