Bump --enable-compiler-plugins to Clang 3.8.0

<https://lists.freedesktop.org/archives/libreoffice/2017-December/079107.html>
"Clang baseline bump"

Change-Id: I18fca8794ea34118fc6308458064d0c28cf5caf7
Reviewed-on: https://gerrit.libreoffice.org/46557
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

32 files changed, 93 insertions, 399 deletions

diff --git a/README.md b/README.md
index 475509abeac1..9721813c23f1 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,7 @@ C++17, C++14, or C++11" in its current form (due to the #pragma GCC diagnostic i
 that it does not understand).
 
 If you want to use Clang with the LibreOffice compiler plugins, the minimal
-version of Clang is 3.4. Since Xcode doesn't provide the compiler plugin
+version of Clang is 3.8. Since Xcode doesn't provide the compiler plugin
 headers, you have to compile your own Clang to use them on macOS.
 
 You can find the TDF configure switches in the distro-configs/ directory.
diff --git a/compilerplugins/clang/check.cxx b/compilerplugins/clang/check.cxx
index 9ded6d296e5f..2a7b0a978348 100644
--- a/compilerplugins/clang/check.cxx
+++ b/compilerplugins/clang/check.cxx
@@ -9,8 +9,9 @@
 
 #include <cassert>
 
+#include <clang/AST/DeclCXX.h>
+
 #include "check.hxx"
-#include "compat.hxx"
 
 namespace loplugin {
 
@@ -153,14 +154,14 @@ ContextCheck DeclCheck::MemberFunction() const {
 TerminalCheck ContextCheck::GlobalNamespace() const {
     return TerminalCheck(
         context_ != nullptr
-        && ((compat::isLookupContext(*context_)
+        && ((context_->isLookupContext()
              ? context_ : context_->getLookupParent())
             ->isTranslationUnit()));
 }
 
 TerminalCheck ContextCheck::StdNamespace() const {
     return TerminalCheck(
-        context_ != nullptr && compat::isStdNamespace(*context_));
+        context_ != nullptr && context_->isStdNamespace());
 }
 
 ContextCheck ContextCheck::AnonymousNamespace() const {
@@ -171,13 +172,7 @@ ContextCheck ContextCheck::AnonymousNamespace() const {
 
 namespace {
 
-bool BaseCheckNotSomethingInterestingSubclass(
-    const clang::CXXRecordDecl *BaseDefinition
-#if CLANG_VERSION < 30800
-    , void *
-#endif
-    )
-{
+bool BaseCheckNotSomethingInterestingSubclass(const clang::CXXRecordDecl *BaseDefinition) {
     if (BaseDefinition) {
         auto tc = TypeCheck(BaseDefinition);
         if (tc.Class("Dialog").GlobalNamespace() || tc.Class("SfxPoolItem").GlobalNamespace()) {
@@ -201,7 +196,7 @@ bool isDerivedFromSomethingInteresting(const clang::CXXRecordDecl *decl) {
     if (// not sure what hasAnyDependentBases() does,
         // but it avoids classes we don't want, e.g. WeakAggComponentImplHelper1
         !decl->hasAnyDependentBases() &&
-        !compat::forallBases(*decl, BaseCheckNotSomethingInterestingSubclass, nullptr, true)) {
+        !decl->forallBases(BaseCheckNotSomethingInterestingSubclass, true)) {
         return true;
     }
     return false;
diff --git a/compilerplugins/clang/checkconfigmacros.cxx b/compilerplugins/clang/checkconfigmacros.cxx
index 46cb35a450c3..7e0a722ef2bb 100644
--- a/compilerplugins/clang/checkconfigmacros.cxx
+++ b/compilerplugins/clang/checkconfigmacros.cxx
@@ -9,9 +9,9 @@
  *
  */
 
+#include <memory>
 #include <set>
 
-#include "compat.hxx"
 #include "plugin.hxx"
 
 #include <clang/Lex/Preprocessor.h>
@@ -37,14 +37,14 @@ class CheckConfigMacros
         explicit CheckConfigMacros( const InstantiationData& data );
         virtual void run() override;
         virtual void MacroDefined( const Token& macroToken, const MacroDirective* info ) override;
-        virtual void MacroUndefined( const Token& macroToken, compat::MacroDefinitionParam
+        virtual void MacroUndefined( const Token& macroToken, MacroDefinition const &
 #if CLANG_VERSION >= 50000
             , MacroDirective const *
 #endif
             ) override;
-        virtual void Ifdef( SourceLocation location, const Token& macroToken, compat::MacroDefinitionParam ) override;
-        virtual void Ifndef( SourceLocation location, const Token& macroToken, compat::MacroDefinitionParam ) override;
-        virtual void Defined( const Token& macroToken, compat::MacroDefinitionParam, SourceRange Range ) override;
+        virtual void Ifdef( SourceLocation location, const Token& macroToken, MacroDefinition const & ) override;
+        virtual void Ifndef( SourceLocation location, const Token& macroToken, MacroDefinition const & ) override;
+        virtual void Defined( const Token& macroToken, MacroDefinition const &, SourceRange Range ) override;
         enum { isPPCallback = true };
     private:
         void checkMacro( const Token& macroToken, SourceLocation location );
@@ -54,7 +54,7 @@ class CheckConfigMacros
 CheckConfigMacros::CheckConfigMacros( const InstantiationData& data )
     : Plugin( data )
     {
-    compat::addPPCallbacks(compiler.getPreprocessor(), this);
+    compiler.getPreprocessor().addPPCallbacks(std::unique_ptr<PPCallbacks>(this));
     }
 
 void CheckConfigMacros::run()
@@ -75,7 +75,7 @@ void CheckConfigMacros::MacroDefined( const Token& macroToken, const MacroDirect
         }
     }
 
-void CheckConfigMacros::MacroUndefined( const Token& macroToken, compat::MacroDefinitionParam
+void CheckConfigMacros::MacroUndefined( const Token& macroToken, MacroDefinition const &
 #if CLANG_VERSION >= 50000
                                         , MacroDirective const *
 #endif
@@ -84,17 +84,17 @@ void CheckConfigMacros::MacroUndefined( const Token& macroToken, compat::MacroDe
     configMacros.erase( macroToken.getIdentifierInfo()->getName());
     }
 
-void CheckConfigMacros::Ifdef( SourceLocation location, const Token& macroToken, compat::MacroDefinitionParam )
+void CheckConfigMacros::Ifdef( SourceLocation location, const Token& macroToken, MacroDefinition const & )
     {
     checkMacro( macroToken, location );
     }
 
-void CheckConfigMacros::Ifndef( SourceLocation location, const Token& macroToken, compat::MacroDefinitionParam )
+void CheckConfigMacros::Ifndef( SourceLocation location, const Token& macroToken, MacroDefinition const & )
     {
     checkMacro( macroToken, location );
     }
 
-void CheckConfigMacros::Defined( const Token& macroToken, compat::MacroDefinitionParam , SourceRange )
+void CheckConfigMacros::Defined( const Token& macroToken, MacroDefinition const &, SourceRange )
     {
     checkMacro( macroToken, macroToken.getLocation());
     }
diff --git a/compilerplugins/clang/compat.hxx b/compilerplugins/clang/compat.hxx
index 60eab1251e28..5a540b8ef695 100644
--- a/compilerplugins/clang/compat.hxx
+++ b/compilerplugins/clang/compat.hxx
@@ -11,26 +11,14 @@
 #define INCLUDED_COMPILERPLUGINS_CLANG_COMPAT_HXX
 
 #include <cstddef>
-#include <memory>
-#include <string>
 
 #include "clang/AST/Decl.h"
-#include "clang/AST/DeclBase.h"
-#include "clang/AST/DeclCXX.h"
 #include "clang/AST/Expr.h"
 #include "clang/AST/ExprCXX.h"
-#include "clang/AST/Type.h"
-#include "clang/Basic/Diagnostic.h"
-#include "clang/Basic/DiagnosticIDs.h"
-#include "clang/Basic/Linkage.h"
 #include "clang/Basic/SourceManager.h"
-#include "clang/Basic/Visibility.h"
 #include "clang/Frontend/CompilerInstance.h"
-#include "clang/Lex/PPCallbacks.h"
-#include "clang/Lex/Preprocessor.h"
+#include "clang/Lex/Lexer.h"
 #include "llvm/ADT/StringRef.h"
-#include "llvm/Support/FileSystem.h"
-#include "llvm/Support/raw_ostream.h"
 
 #include "config_clang.h"
 
@@ -46,37 +34,6 @@ inline llvm::StringRef take_front(llvm::StringRef ref, std::size_t N = 1) {
 #endif
 }
 
-inline bool isLookupContext(clang::DeclContext const & ctxt) {
-#if CLANG_VERSION >= 30700
-    return ctxt.isLookupContext();
-#else
-    return !ctxt.isFunctionOrMethod()
-        && ctxt.getDeclKind() != clang::Decl::LinkageSpec;
-#endif
-}
-
-inline bool forallBases(
-    clang::CXXRecordDecl const & decl,
-    clang::CXXRecordDecl::ForallBasesCallback BaseMatches,
-    void* callbackParam,
-    bool AllowShortCircuit)
-{
-#if CLANG_VERSION >= 30800
-    (void) callbackParam;
-    return decl.forallBases(BaseMatches, AllowShortCircuit);
-#else
-    return decl.forallBases(BaseMatches, callbackParam, AllowShortCircuit);
-#endif
-}
-
-inline clang::QualType getReturnType(clang::FunctionDecl const & decl) {
-#if CLANG_VERSION >= 30500
-    return decl.getReturnType();
-#else
-    return decl.getResultType();
-#endif
-}
-
 
 #if CLANG_VERSION >= 30900
 inline clang::ArrayRef<clang::ParmVarDecl *> parameters(
@@ -84,127 +41,14 @@ inline clang::ArrayRef<clang::ParmVarDecl *> parameters(
 {
     return decl.parameters();
 }
-#elif CLANG_VERSION >= 30500
+#else
 inline clang::FunctionDecl::param_const_range parameters(
     clang::FunctionDecl const & decl)
 {
     return decl.params();
 }
-#else
-struct FunctionDeclParamsWrapper
-{
-    clang::FunctionDecl const & decl;
-    FunctionDeclParamsWrapper(clang::FunctionDecl const & _decl) : decl(_decl) {}
-    clang::FunctionDecl::param_const_iterator begin() const { return decl.param_begin(); }
-    clang::FunctionDecl::param_const_iterator end() const { return decl.param_end(); }
-};
-inline FunctionDeclParamsWrapper parameters(
-    clang::FunctionDecl const & decl)
-{
-    return FunctionDeclParamsWrapper(decl);
-}
-#endif
-
-
-inline clang::QualType getReturnType(clang::FunctionProtoType const & type) {
-#if CLANG_VERSION >= 30500
-    return type.getReturnType();
-#else
-    return type.getResultType();
-#endif
-}
-
-inline unsigned getNumParams(clang::FunctionProtoType const & type) {
-#if CLANG_VERSION >= 30500
-    return type.getNumParams();
-#else
-    return type.getNumArgs();
-#endif
-}
-
-inline clang::QualType getParamType(
-    clang::FunctionProtoType const & type, unsigned i)
-{
-#if CLANG_VERSION >= 30500
-    return type.getParamType(i);
-#else
-    return type.getArgType(i);
-#endif
-}
-
-inline clang::Stmt::const_child_iterator begin(
-    clang::Stmt::const_child_range const & range)
-{
-#if CLANG_VERSION >= 30800
-    return range.begin();
-#else
-    return range.first;
-#endif
-}
-
-inline clang::Stmt::const_child_iterator end(
-    clang::Stmt::const_child_range const & range)
-{
-#if CLANG_VERSION >= 30800
-    return range.end();
-#else
-    return range.second;
-#endif
-}
-
-inline unsigned getBuiltinCallee(clang::CallExpr const & expr) {
-#if CLANG_VERSION >= 30500
-    return expr.getBuiltinCallee();
-#else
-    return expr.isBuiltinCall();
-#endif
-}
-
-inline unsigned getCustomDiagID(
-    clang::DiagnosticsEngine & engine, clang::DiagnosticsEngine::Level L,
-    llvm::StringRef FormatString)
-{
-#if CLANG_VERSION >= 30500
-    return engine.getDiagnosticIDs()->getCustomDiagID(
-        static_cast<clang::DiagnosticIDs::Level>(L), FormatString);
-#else
-    return engine.getCustomDiagID(L, FormatString);
-#endif
-}
-
-inline std::unique_ptr<llvm::raw_fd_ostream> create_raw_fd_ostream(
-    char const * Filename, std::string & ErrorInfo)
-{
-#if CLANG_VERSION >= 30600
-    std::error_code ec;
-    std::unique_ptr<llvm::raw_fd_ostream> s(
-        new llvm::raw_fd_ostream(Filename, ec, llvm::sys::fs::F_None));
-    ErrorInfo = ec ? "error: " + ec.message() : std::string();
-    return s;
-#elif CLANG_VERSION >= 30500
-    return std::unique_ptr<llvm::raw_fd_ostream>(
-        new llvm::raw_fd_ostream(Filename, ErrorInfo, llvm::sys::fs::F_None));
-#else
-    return std::unique_ptr<llvm::raw_fd_ostream>(
-        new llvm::raw_fd_ostream(Filename, ErrorInfo));
-#endif
-}
-
-#if CLANG_VERSION >= 30700
-using MacroDefinitionParam = clang::MacroDefinition const &;
-#else
-using MacroDefinitionParam = clang::MacroDirective const *;
 #endif
 
-inline void addPPCallbacks(
-    clang::Preprocessor & preprocessor, clang::PPCallbacks * C)
-{
-#if CLANG_VERSION >= 30600
-    preprocessor.addPPCallbacks(std::unique_ptr<clang::PPCallbacks>(C));
-#else
-    preprocessor.addPPCallbacks(C);
-#endif
-}
 
 inline bool isPointWithin(
     clang::SourceManager const & SM, clang::SourceLocation Location, clang::SourceLocation Start,
@@ -272,37 +116,6 @@ inline llvm::StringRef getImmediateMacroNameForDiagnostics(
 #endif
 }
 
-inline auto getAsTagDecl(clang::Type const& t) -> clang::TagDecl *
-{
-#if CLANG_VERSION >= 30500
-    // TODO not sure if it works with clang 3.6, trunk is known to work
-    return t.getAsTagDecl();
-#else
-    return t.getAs<clang::TagType>()->getDecl();
-#endif
-}
-
-inline bool isStdNamespace(clang::DeclContext const & context) {
-#if CLANG_VERSION >= 30500
-    return context.isStdNamespace();
-#else
-    // cf. lib/AST/DeclBase.cpp:
-    if (!context.isNamespace()) {
-        return false;
-    }
-    const clang::NamespaceDecl *ND = clang::cast<clang::NamespaceDecl>(
-        &context);
-    if (ND->isInline()) {
-        return isStdNamespace(*ND->getParent());
-    }
-    if (!context.getParent()->getRedeclContext()->isTranslationUnit()) {
-        return false;
-    }
-    const clang::IdentifierInfo *II = ND->getIdentifier();
-    return II && II->isStr("std");
-#endif
-}
-
 // Work around <http://reviews.llvm.org/D22128>:
 //
 // SfxErrorHandler::GetClassString (svtools/source/misc/ehdl.cxx):
diff --git a/compilerplugins/clang/constantparam.cxx b/compilerplugins/clang/constantparam.cxx
index e09050a2af12..461eb52a2e97 100644
--- a/compilerplugins/clang/constantparam.cxx
+++ b/compilerplugins/clang/constantparam.cxx
@@ -107,12 +107,8 @@ void ConstantParam::addToCallSet(const FunctionDecl* functionDecl, int paramInde
         functionDecl = functionDecl->getInstantiatedFromMemberFunction();
     else if (functionDecl->getClassScopeSpecializationPattern())
         functionDecl = functionDecl->getClassScopeSpecializationPattern();
-// workaround clang-3.5 issue
-#if CLANG_VERSION >= 30600
     else if (functionDecl->getTemplateInstantiationPattern())
         functionDecl = functionDecl->getTemplateInstantiationPattern();
-#endif
-
 
     if (!functionDecl->getNameInfo().getLoc().isValid())
         return;
@@ -131,7 +127,7 @@ void ConstantParam::addToCallSet(const FunctionDecl* functionDecl, int paramInde
 
 
     MyCallSiteInfo aInfo;
-    aInfo.returnType = compat::getReturnType(*functionDecl).getCanonicalType().getAsString();
+    aInfo.returnType = functionDecl->getReturnType().getCanonicalType().getAsString();
 
     if (isa<CXXMethodDecl>(functionDecl)) {
         const CXXRecordDecl* recordDecl = dyn_cast<CXXMethodDecl>(functionDecl)->getParent();
@@ -259,11 +255,8 @@ bool ConstantParam::VisitCallExpr(const CallExpr * callExpr) {
         functionDecl = functionDecl->getInstantiatedFromMemberFunction();
     else if (functionDecl->getClassScopeSpecializationPattern())
         functionDecl = functionDecl->getClassScopeSpecializationPattern();
-// workaround clang-3.5 issue
-#if CLANG_VERSION >= 30600
     else if (functionDecl->getTemplateInstantiationPattern())
         functionDecl = functionDecl->getTemplateInstantiationPattern();
-#endif
 
     unsigned len = std::max(callExpr->getNumArgs(), functionDecl->getNumParams());
     for (unsigned i = 0; i < len; ++i) {
diff --git a/compilerplugins/clang/countusersofdefaultparams.cxx b/compilerplugins/clang/countusersofdefaultparams.cxx
index de0ab7e741cf..d86e66a35490 100644
--- a/compilerplugins/clang/countusersofdefaultparams.cxx
+++ b/compilerplugins/clang/countusersofdefaultparams.cxx
@@ -95,11 +95,8 @@ void CountUsersOfDefaultParams::niceName(const FunctionDecl* functionDecl, MyFun
         functionDecl = functionDecl->getInstantiatedFromMemberFunction();
     else if (functionDecl->getClassScopeSpecializationPattern())
         functionDecl = functionDecl->getClassScopeSpecializationPattern();
-// workaround clang-3.5 issue
-#if CLANG_VERSION >= 30600
     else if (functionDecl->getTemplateInstantiationPattern())
         functionDecl = functionDecl->getTemplateInstantiationPattern();
-#endif
 
     switch (functionDecl->getAccess())
     {
@@ -108,7 +105,7 @@ void CountUsersOfDefaultParams::niceName(const FunctionDecl* functionDecl, MyFun
     case AS_protected: aInfo.access = "protected"; break;
     default: aInfo.access = "unknown"; break;
     }
-    aInfo.returnType = compat::getReturnType(*functionDecl).getCanonicalType().getAsString();
+    aInfo.returnType = functionDecl->getReturnType().getCanonicalType().getAsString();
 
     if (isa<CXXMethodDecl>(functionDecl)) {
         const CXXRecordDecl* recordDecl = dyn_cast<CXXMethodDecl>(functionDecl)->getParent();
@@ -160,11 +157,8 @@ bool CountUsersOfDefaultParams::VisitCallExpr(const CallExpr * callExpr) {
         functionDecl = functionDecl->getInstantiatedFromMemberFunction();
     else if (functionDecl->getClassScopeSpecializationPattern())
         functionDecl = functionDecl->getClassScopeSpecializationPattern();
-// workaround clang-3.5 issue
-#if CLANG_VERSION >= 30600
     else if (functionDecl->getTemplateInstantiationPattern())
         functionDecl = functionDecl->getTemplateInstantiationPattern();
-#endif
     int n = functionDecl->getNumParams() - 1;
     if (n < 0 || !functionDecl->getParamDecl(n)->hasDefaultArg()) {
         return true;
@@ -192,11 +186,8 @@ bool CountUsersOfDefaultParams::VisitCXXConstructExpr(const CXXConstructExpr * c
         constructorDecl = dyn_cast<CXXConstructorDecl>(constructorDecl->getInstantiatedFromMemberFunction());
     else if (constructorDecl->getClassScopeSpecializationPattern())
         constructorDecl = dyn_cast<CXXConstructorDecl>(constructorDecl->getClassScopeSpecializationPattern());
-// workaround clang-3.5 issue
-#if CLANG_VERSION >= 30600
     else if (constructorDecl->getTemplateInstantiationPattern())
         constructorDecl = dyn_cast<CXXConstructorDecl>(constructorDecl->getTemplateInstantiationPattern());
-#endif
     int n = constructorDecl->getNumParams() - 1;
     if (n < 0 || !constructorDecl->getParamDecl(n)->hasDefaultArg()) {
         return true;
diff --git a/compilerplugins/clang/datamembershadow.cxx b/compilerplugins/clang/datamembershadow.cxx
index cc2ec7675b8d..040743bad028 100644
--- a/compilerplugins/clang/datamembershadow.cxx
+++ b/compilerplugins/clang/datamembershadow.cxx
@@ -100,8 +100,6 @@ bool DataMemberShadow::VisitFieldDecl(FieldDecl const * fieldDecl)
 
     fieldDecl = fieldDecl->getCanonicalDecl();
 
-#if CLANG_VERSION >= 30800
-
     auto BaseMatchesCallback = [&](const CXXBaseSpecifier *cxxBaseSpecifier, CXXBasePath& Paths)
     {
         if (!cxxBaseSpecifier->getType().getTypePtr())
@@ -143,7 +141,6 @@ bool DataMemberShadow::VisitFieldDecl(FieldDecl const * fieldDecl)
 
     CXXBasePaths aPaths;
     parentCXXRecordDecl->lookupInBases(BaseMatchesCallback, aPaths);
-#endif
     return true;
 }
 
diff --git a/compilerplugins/clang/expandablemethods.cxx b/compilerplugins/clang/expandablemethods.cxx
index 2f2c3a2d68db..6d70ad81cefa 100644
--- a/compilerplugins/clang/expandablemethods.cxx
+++ b/compilerplugins/clang/expandablemethods.cxx
@@ -116,11 +116,8 @@ MyFuncInfo ExpandableMethods::niceName(const FunctionDecl* functionDecl)
         functionDecl = functionDecl->getInstantiatedFromMemberFunction();
     else if (functionDecl->getClassScopeSpecializationPattern())
         functionDecl = functionDecl->getClassScopeSpecializationPattern();
-// workaround clang-3.5 issue
-#if CLANG_VERSION >= 30600
     else if (functionDecl->getTemplateInstantiationPattern())
         functionDecl = functionDecl->getTemplateInstantiationPattern();
-#endif
 
     MyFuncInfo aInfo;
     switch (functionDecl->getAccess())
@@ -131,7 +128,7 @@ MyFuncInfo ExpandableMethods::niceName(const FunctionDecl* functionDecl)
     default: aInfo.access = "unknown"; break;
     }
     if (!isa<CXXConstructorDecl>(functionDecl)) {
-        aInfo.returnType = compat::getReturnType(*functionDecl).getCanonicalType().getAsString();
+        aInfo.returnType = functionDecl->getReturnType().getCanonicalType().getAsString();
     } else {
         aInfo.returnType = "";
     }
diff --git a/compilerplugins/clang/getimplementationname.cxx b/compilerplugins/clang/getimplementationname.cxx
index 81c3473aa678..4c8f2d19ee73 100644
--- a/compilerplugins/clang/getimplementationname.cxx
+++ b/compilerplugins/clang/getimplementationname.cxx
@@ -13,7 +13,6 @@
 // only compile this on clang 3.7 or higher, which is known to work
 // there were problems on clang 3.5 at least
 #include "config_clang.h"
-#if CLANG_VERSION >= 30700
 #include <cassert>
 #include <stdlib.h>
 #include <string>
@@ -312,6 +311,5 @@ loplugin::Plugin::Registration<GetImplementationName> X(
     "getimplementationname", false);
 }
 #endif
-#endif
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/compilerplugins/clang/implicitboolconversion.cxx b/compilerplugins/clang/implicitboolconversion.cxx
index 41f6fd56bcae..d7e80f56ab36 100644
--- a/compilerplugins/clang/implicitboolconversion.cxx
+++ b/compilerplugins/clang/implicitboolconversion.cxx
@@ -19,30 +19,6 @@
 #include "compat.hxx"
 #include "plugin.hxx"
 
-#if CLANG_VERSION < 30700
-
-namespace std {
-
-template<> struct iterator_traits<ExprIterator> {
-    typedef std::ptrdiff_t difference_type;
-    typedef Expr * value_type;
-    typedef Expr const ** pointer;
-    typedef Expr const & reference;
-    typedef std::random_access_iterator_tag iterator_category;
-};
-
-template<> struct iterator_traits<ConstExprIterator> {
-    typedef std::ptrdiff_t difference_type;
-    typedef Expr const * value_type;
-    typedef Expr const ** pointer;
-    typedef Expr const & reference;
-    typedef std::random_access_iterator_tag iterator_category;
-};
-
-}
-
-#endif
-
 namespace {
 
 Expr const * ignoreParenAndTemporaryMaterialization(Expr const * expr) {
@@ -334,19 +310,19 @@ bool ImplicitBoolConversion::TraverseCallExpr(CallExpr * expr) {
             std::ptrdiff_t n = j - expr->arg_begin();
             assert(n >= 0);
             if (t != nullptr
-                && static_cast<std::size_t>(n) >= compat::getNumParams(*t))
+                && static_cast<std::size_t>(n) >= t->getNumParams())
             {
                 assert(t->isVariadic());
                 // ignore bool to int promotions of variadic arguments
             } else if (bExt) {
                 if (t != nullptr) {
                     assert(
-                        static_cast<std::size_t>(n) < compat::getNumParams(*t));
-                    if (!(compat::getParamType(*t, n)->isSpecificBuiltinType(
+                        static_cast<std::size_t>(n) < t->getNumParams());
+                    if (!(t->getParamType(n)->isSpecificBuiltinType(
                               BuiltinType::Int)
-                          || compat::getParamType(*t, n)->isSpecificBuiltinType(
+                          || t->getParamType(n)->isSpecificBuiltinType(
                               BuiltinType::UInt)
-                          || compat::getParamType(*t, n)->isSpecificBuiltinType(
+                          || t->getParamType(n)->isSpecificBuiltinType(
                               BuiltinType::Long)))
                     {
                         reportWarning(i);
@@ -831,7 +807,7 @@ bool ImplicitBoolConversion::TraverseReturnStmt(ReturnStmt * stmt) {
 bool ImplicitBoolConversion::TraverseFunctionDecl(FunctionDecl * decl) {
     bool bExt = false;
     if (hasCLanguageLinkageType(decl) && decl->isThisDeclarationADefinition()) {
-        QualType t { compat::getReturnType(*decl) };
+        QualType t { decl->getReturnType() };
         if (t->isSpecificBuiltinType(BuiltinType::Int)
             || t->isSpecificBuiltinType(BuiltinType::UInt))
         {
diff --git a/compilerplugins/clang/includeform.cxx b/compilerplugins/clang/includeform.cxx
index bf3d689c603b..4994e8ddd75b 100644
--- a/compilerplugins/clang/includeform.cxx
+++ b/compilerplugins/clang/includeform.cxx
@@ -7,6 +7,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+#include <memory>
+
 #include "compat.hxx"
 #include "plugin.hxx"
 
@@ -16,7 +18,7 @@ class IncludeForm final: public PPCallbacks, public loplugin::RewritePlugin {
 public:
     explicit IncludeForm(loplugin::InstantiationData const & data):
         RewritePlugin(data)
-    { compat::addPPCallbacks(compiler.getPreprocessor(), this); }
+    { compiler.getPreprocessor().addPPCallbacks(std::unique_ptr<PPCallbacks>(this)); }
 
 private:
     void run() override {}
diff --git a/compilerplugins/clang/inlinesimplememberfunctions.cxx b/compilerplugins/clang/inlinesimplememberfunctions.cxx
index de8de482513b..9a1d1f6f3abb 100644
--- a/compilerplugins/clang/inlinesimplememberfunctions.cxx
+++ b/compilerplugins/clang/inlinesimplememberfunctions.cxx
@@ -31,10 +31,10 @@ private:
 };
 
 static bool oneAndOnlyOne(clang::Stmt::const_child_range range) {
-    if (compat::begin(range) == compat::end(range)) {
+    if (range.begin() == range.end()) {
         return false;
     }
-    if (++compat::begin(range) != compat::end(range)) {
+    if (++range.begin() != range.end()) {
         return false;
     }
     return true;
@@ -133,7 +133,7 @@ bool InlineSimpleMemberFunctions::VisitCXXMethodDecl(const CXXMethodDecl * funct
         {
             childStmt2 = *childStmt2->child_begin();
             if (dyn_cast<CXXThisExpr>( childStmt2 ) != nullptr
-                && compat::begin(childStmt2->children()) == compat::end(childStmt2->children()))
+                && childStmt2->children().begin() == childStmt2->children().end())
             {
                 return true;
             }
@@ -144,7 +144,7 @@ bool InlineSimpleMemberFunctions::VisitCXXMethodDecl(const CXXMethodDecl * funct
     {
         const Stmt* childStmt2 = *childStmt->child_begin();
         if (dyn_cast<CXXThisExpr>( childStmt2 ) != nullptr
-            && compat::begin(childStmt2->children()) == compat::end(childStmt2->children()))
+            && childStmt2->children().begin() == childStmt2->children().end())
         {
             return true;
         }
@@ -207,7 +207,7 @@ bool InlineSimpleMemberFunctions::VisitCXXMethodDecl(const CXXMethodDecl * funct
                 }
              return true;
         }
-        if ( compat::begin(childStmt->children()) == compat::end(childStmt->children()) )
+        if ( childStmt->children().begin() == childStmt->children().end() )
             return true;
         childStmt = *childStmt->child_begin();
     }
diff --git a/compilerplugins/clang/oslendian.cxx b/compilerplugins/clang/oslendian.cxx
index 2a7bfa6b2efb..75b1dcfdde9f 100644
--- a/compilerplugins/clang/oslendian.cxx
+++ b/compilerplugins/clang/oslendian.cxx
@@ -8,8 +8,8 @@
  */
 
 #include <cassert>
+#include <memory>
 
-#include "compat.hxx"
 #include "plugin.hxx"
 
 namespace {
@@ -17,7 +17,7 @@ namespace {
 class OslEndian: public loplugin::Plugin, public PPCallbacks {
 public:
     explicit OslEndian(loplugin::InstantiationData const & data): Plugin(data) {
-        compat::addPPCallbacks(compiler.getPreprocessor(), this);
+        compiler.getPreprocessor().addPPCallbacks(std::unique_ptr<PPCallbacks>(this));
     }
 
     enum { isPPCallback = true };
@@ -59,7 +59,7 @@ private:
     }
 
     void MacroUndefined(
-        Token const & MacroNameTok, compat::MacroDefinitionParam
+        Token const & MacroNameTok, MacroDefinition const &
 #if CLANG_VERSION >= 50000
         , MacroDirective const *
 #endif
@@ -75,7 +75,7 @@ private:
     }
 
     void Defined(
-        Token const & MacroNameTok, compat::MacroDefinitionParam, SourceRange)
+        Token const & MacroNameTok, MacroDefinition const &, SourceRange)
         override
     {
         check(MacroNameTok);
@@ -83,14 +83,14 @@ private:
 
     void Ifdef(
         SourceLocation, Token const & MacroNameTok,
-        compat::MacroDefinitionParam) override
+        MacroDefinition const &) override
     {
         check(MacroNameTok);
     }
 
     void Ifndef(
         SourceLocation, Token const & MacroNameTok,
-        compat::MacroDefinitionParam) override
+        MacroDefinition const &) override
     {
         check(MacroNameTok);
     }
diff --git a/compilerplugins/clang/passstuffbyref.cxx b/compilerplugins/clang/passstuffbyref.cxx
index 3b4b974c697f..8c522efb5dbe 100644
--- a/compilerplugins/clang/passstuffbyref.cxx
+++ b/compilerplugins/clang/passstuffbyref.cxx
@@ -11,7 +11,6 @@
 #include <set>
 
 #include "check.hxx"
-#include "compat.hxx"
 #include "plugin.hxx"
 
 // Find places where various things are passed by value.
@@ -222,7 +221,7 @@ void PassStuffByRef::checkReturnValue(const FunctionDecl * functionDecl, const C
         return;
     }
 
-    const QualType type = compat::getReturnType(*functionDecl).getDesugaredType(compiler.getASTContext());
+    const QualType type = functionDecl->getReturnType().getDesugaredType(compiler.getASTContext());
     if (type->isReferenceType() || type->isIntegralOrEnumerationType() || type->isPointerType()
         || type->isTemplateTypeParmType() || type->isDependentType() || type->isBuiltinType()
         || type->isScalarType())
diff --git a/compilerplugins/clang/pluginhandler.cxx b/compilerplugins/clang/pluginhandler.cxx
index 1740a5d05486..433bd0a9efad 100644
--- a/compilerplugins/clang/pluginhandler.cxx
+++ b/compilerplugins/clang/pluginhandler.cxx
@@ -10,7 +10,8 @@
  */
 
 #include <memory>
-#include "compat.hxx"
+#include <system_error>
+
 #include "plugin.hxx"
 #include "pluginhandler.hxx"
 
@@ -168,9 +169,9 @@ DiagnosticBuilder PluginHandler::report( DiagnosticsEngine::Level level, const c
     }
     fullMessage += "]";
     if( loc.isValid())
-        return diag.Report( loc, compat::getCustomDiagID(diag, level, fullMessage) );
+        return diag.Report( loc, diag.getDiagnosticIDs()->getCustomDiagID(static_cast<DiagnosticIDs::Level>(level), fullMessage) );
     else
-        return diag.Report( compat::getCustomDiagID(diag, level, fullMessage) );
+        return diag.Report( diag.getDiagnosticIDs()->getCustomDiagID(static_cast<DiagnosticIDs::Level>(level), fullMessage) );
 }
 
 DiagnosticBuilder PluginHandler::report( DiagnosticsEngine::Level level, StringRef message, SourceLocation loc )
@@ -305,15 +306,18 @@ void PluginHandler::HandleTranslationUnit( ASTContext& context )
         sprintf( filename, "%s.new.%d", modifyFile.c_str(), getpid());
         std::string error;
         bool bOk = false;
+        std::error_code ec;
         std::unique_ptr<raw_fd_ostream> ostream(
-            compat::create_raw_fd_ostream(filename, error) );
-        if( error.empty())
+            new raw_fd_ostream(filename, ec, sys::fs::F_None));
+        if( !ec)
         {
             it->second.write( *ostream );
             ostream->close();
             if( !ostream->has_error() && rename( filename, modifyFile.c_str()) == 0 )
                 bOk = true;
         }
+        else
+            error = "error: " + ec.message();
         ostream->clear_error();
         unlink( filename );
         if( !bOk )
@@ -323,17 +327,10 @@ void PluginHandler::HandleTranslationUnit( ASTContext& context )
 #endif
  }
 
-#if CLANG_VERSION >= 30600
 std::unique_ptr<ASTConsumer> LibreOfficeAction::CreateASTConsumer( CompilerInstance& Compiler, StringRef )
 {
     return llvm::make_unique<PluginHandler>( Compiler, _args );
 }
-#else
-ASTConsumer* LibreOfficeAction::CreateASTConsumer( CompilerInstance& Compiler, StringRef )
-{
-    return new PluginHandler( Compiler, _args );
-}
-#endif
 
 bool LibreOfficeAction::ParseArgs( const CompilerInstance&, const std::vector< std::string >& args )
 {
diff --git a/compilerplugins/clang/pluginhandler.hxx b/compilerplugins/clang/pluginhandler.hxx
index 2befaf7fc6a8..ea0eb2444506 100644
--- a/compilerplugins/clang/pluginhandler.hxx
+++ b/compilerplugins/clang/pluginhandler.hxx
@@ -80,11 +80,7 @@ class LibreOfficeAction
     : public PluginASTAction
 {
 public:
-#if CLANG_VERSION >= 30600
     virtual std::unique_ptr<ASTConsumer> CreateASTConsumer( CompilerInstance& Compiler, StringRef InFile );
-#else
-    virtual ASTConsumer* CreateASTConsumer( CompilerInstance& Compiler, StringRef InFile );
-#endif
 
     virtual bool ParseArgs( const CompilerInstance& CI, const std::vector< std::string >& args );
 private:
diff --git a/compilerplugins/clang/redundantcast.cxx b/compilerplugins/clang/redundantcast.cxx
index 2f905d355720..c4d50424b1a0 100644
--- a/compilerplugins/clang/redundantcast.cxx
+++ b/compilerplugins/clang/redundantcast.cxx
@@ -103,20 +103,10 @@ public:
         }
     }
 
-    bool TraverseInitListExpr(
-        InitListExpr * expr
-#if CLANG_VERSION >= 30800
-        , DataRecursionQueue * queue = nullptr
-#endif
-        )
-    {
+    bool TraverseInitListExpr(InitListExpr * expr, DataRecursionQueue * queue = nullptr) {
         return WalkUpFromInitListExpr(expr)
             && TraverseSynOrSemInitListExpr(
-                expr->isSemanticForm() ? expr : expr->getSemanticForm()
-#if CLANG_VERSION >= 30800
-                , queue
-#endif
-                );
+                expr->isSemanticForm() ? expr : expr->getSemanticForm(), queue);
     }
 
     bool VisitImplicitCastExpr(ImplicitCastExpr const * expr);
@@ -806,7 +796,7 @@ bool RedundantCast::visitBinOp(BinaryOperator const * expr) {
 
 bool RedundantCast::isOverloadedFunction(FunctionDecl const * decl) {
     auto const ctx = decl->getDeclContext();
-    if (!compat::isLookupContext(*ctx)) {
+    if (!ctx->isLookupContext()) {
         return false;
     }
     auto const canon = decl->getCanonicalDecl();
diff --git a/compilerplugins/clang/refcounting.cxx b/compilerplugins/clang/refcounting.cxx
index 58a9884ede0d..b902db4efd10 100644
--- a/compilerplugins/clang/refcounting.cxx
+++ b/compilerplugins/clang/refcounting.cxx
@@ -11,7 +11,6 @@
 #include <iostream>
 
 #include "check.hxx"
-#include "compat.hxx"
 #include "plugin.hxx"
 #include "clang/AST/CXXInheritance.h"
 
@@ -95,15 +94,10 @@ bool isDerivedFrom(const CXXRecordDecl *decl, DeclChecker base) {
     if (!decl->hasDefinition()) {
         return false;
     }
-    if (!compat::forallBases(
-            *decl,
-#if CLANG_VERSION < 30800
-            BaseCheckNotSubclass,
-#else
+    if (!decl->forallBases(
             [&base](const CXXRecordDecl *BaseDefinition) -> bool
                 { return BaseCheckNotSubclass(BaseDefinition, &base); },
-#endif
-            &base, true))
+            true))
     {
         return true;
     }
@@ -550,7 +544,7 @@ bool RefCounting::VisitFunctionDecl(const FunctionDecl * functionDecl) {
     if (methodDecl && methodDecl->size_overridden_methods() > 0) {
             return true;
     }
-    checkUnoReference(compat::getReturnType(*functionDecl), functionDecl, nullptr, "return");
+    checkUnoReference(functionDecl->getReturnType(), functionDecl, nullptr, "return");
     return true;
 }
 
diff --git a/compilerplugins/clang/reservedid.cxx b/compilerplugins/clang/reservedid.cxx
index 82bbc7ea033c..5fefb26c2589 100644
--- a/compilerplugins/clang/reservedid.cxx
+++ b/compilerplugins/clang/reservedid.cxx
@@ -59,7 +59,6 @@ void ReservedId::run() {
     if (TraverseDecl(compiler.getASTContext().getTranslationUnitDecl())
         && compiler.hasPreprocessor())
     {
-#if CLANG_VERSION >= 30700
         auto & prep = compiler.getPreprocessor();
         for (auto const & m: prep.macros(false)) {
             auto id = m.first->getName();
@@ -129,7 +128,6 @@ void ReservedId::run() {
                 }
             }
         }
-#endif
     }
 }
 
diff --git a/compilerplugins/clang/salbool.cxx b/compilerplugins/clang/salbool.cxx
index 2402986467b1..e828dbfcfc55 100644
--- a/compilerplugins/clang/salbool.cxx
+++ b/compilerplugins/clang/salbool.cxx
@@ -108,7 +108,7 @@ BoolOverloadKind isBoolOverloadOf(
 // encounter in practice:
 bool hasBoolOverload(FunctionDecl const * decl, bool mustBeDeleted) {
     auto ctx = decl->getDeclContext();
-    if (!compat::isLookupContext(*ctx)) {
+    if (!ctx->isLookupContext()) {
         return false;
     }
     auto res = ctx->lookup(decl->getDeclName());
@@ -285,8 +285,8 @@ bool SalBool::VisitCallExpr(CallExpr * expr) {
         }
     }
     if (ft != nullptr) {
-        for (unsigned i = 0; i != compat::getNumParams(*ft); ++i) {
-            QualType t(compat::getParamType(*ft, i));
+        for (unsigned i = 0; i != ft->getNumParams(); ++i) {
+            QualType t(ft->getParamType(i));
             bool b = false;
             if (t->isLValueReferenceType()) {
                 t = t.getNonReferenceType();
@@ -688,7 +688,7 @@ bool SalBool::VisitFunctionDecl(FunctionDecl const * decl) {
     if (ignoreLocation(decl)) {
         return true;
     }
-    if (isSalBool(compat::getReturnType(*decl).getNonReferenceType())
+    if (isSalBool(decl->getReturnType().getNonReferenceType())
         && !(decl->isDeletedAsWritten() && isa<CXXConversionDecl>(decl)))
     {
         FunctionDecl const * f = decl->getCanonicalDecl();
diff --git a/compilerplugins/clang/sfxpoolitem.cxx b/compilerplugins/clang/sfxpoolitem.cxx
index d2d469d2f4a3..d269070e03fe 100644
--- a/compilerplugins/clang/sfxpoolitem.cxx
+++ b/compilerplugins/clang/sfxpoolitem.cxx
@@ -11,7 +11,6 @@
 #include <iostream>
 
 #include "plugin.hxx"
-#include "compat.hxx"
 #include "check.hxx"
 #include "clang/AST/CXXInheritance.h"
 
@@ -34,13 +33,7 @@ public:
     bool VisitCXXRecordDecl( const CXXRecordDecl* );
 };
 
-bool BaseCheckNotSfxPoolItemSubclass(
-    const CXXRecordDecl *BaseDefinition
-#if CLANG_VERSION < 30800
-    , void *
-#endif
-    )
-{
+bool BaseCheckNotSfxPoolItemSubclass(const CXXRecordDecl *BaseDefinition) {
     if (BaseDefinition && loplugin::TypeCheck(BaseDefinition).Class("SfxPoolItem").GlobalNamespace()) {
         return false;
     }
@@ -58,20 +51,14 @@ bool isDerivedFromSfxPoolItem(const CXXRecordDecl *decl) {
     if (// not sure what hasAnyDependentBases() does,
         // but it avoids classes we don't want, e.g. WeakAggComponentImplHelper1
         !decl->hasAnyDependentBases() &&
-        !compat::forallBases(*decl, BaseCheckNotSfxPoolItemSubclass, nullptr, true)) {
+        !decl->forallBases(BaseCheckNotSfxPoolItemSubclass, true)) {
         return true;
     }
     return false;
 }
 
 
-bool BaseCheckNotSwMsgPoolItemSubclass(
-    const CXXRecordDecl *BaseDefinition
-#if CLANG_VERSION < 30800
-    , void *
-#endif
-    )
-{
+bool BaseCheckNotSwMsgPoolItemSubclass(const CXXRecordDecl *BaseDefinition) {
     if (BaseDefinition && loplugin::TypeCheck(BaseDefinition).Class("SwMsgPoolItem")) {
         return false;
     }
@@ -89,7 +76,7 @@ bool isDerivedFromSwMsgPoolItem(const CXXRecordDecl *decl) {
     if (// not sure what hasAnyDependentBases() does,
         // but it avoids classes we don't want, e.g. WeakAggComponentImplHelper1
         !decl->hasAnyDependentBases() &&
-        !compat::forallBases(*decl, BaseCheckNotSwMsgPoolItemSubclass, nullptr, true)) {
+        !decl->forallBases(BaseCheckNotSwMsgPoolItemSubclass, true)) {
         return true;
     }
     return false;
diff --git a/compilerplugins/clang/singlevalfields.cxx b/compilerplugins/clang/singlevalfields.cxx
index 85d77b005562..61cfe044d1fd 100644
--- a/compilerplugins/clang/singlevalfields.cxx
+++ b/compilerplugins/clang/singlevalfields.cxx
@@ -13,7 +13,6 @@
 #include <fstream>
 #include <set>
 #include "plugin.hxx"
-#include "compat.hxx"
 
 /**
 Look for fields that are only ever assigned a single constant value.
@@ -262,7 +261,7 @@ bool SingleValFields::VisitMemberExpr( const MemberExpr* memberExpr )
     if (parentFunction && parent && isa<ReturnStmt>(parent)) {
         const Stmt* parent2 = getParentStmt(parent);
         if (parent2 && isa<CompoundStmt>(parent2)) {
-            QualType qt = compat::getReturnType(*parentFunction).getDesugaredType(compiler.getASTContext());
+            QualType qt = parentFunction->getReturnType().getDesugaredType(compiler.getASTContext());
             if (!qt.isConstQualified() && qt->isReferenceType()) {
                 bPotentiallyAssignedTo = true;
             }
@@ -449,10 +448,10 @@ void SingleValFields::checkCallExpr(const Stmt* child, const CallExpr* callExpr,
         return;
     }
     for (unsigned i = 0; i < callExpr->getNumArgs(); ++i) {
-        if (i >= compat::getNumParams(*proto)) // can happen in template code
+        if (i >= proto->getNumParams()) // can happen in template code
             break;
         if (callExpr->getArg(i) == child) {
-            QualType qt = compat::getParamType(*proto, i).getDesugaredType(compiler.getASTContext());
+            QualType qt = proto->getParamType(i).getDesugaredType(compiler.getASTContext());
             if (!qt.isConstQualified() && qt->isReferenceType()) {
                 assignValue = "?";
                 bPotentiallyAssignedTo = true;
diff --git a/compilerplugins/clang/staticmethods.cxx b/compilerplugins/clang/staticmethods.cxx
index 7d5b23a7ba04..f4e1f068ec0e 100644
--- a/compilerplugins/clang/staticmethods.cxx
+++ b/compilerplugins/clang/staticmethods.cxx
@@ -10,7 +10,6 @@
 #include "clang/AST/Attr.h"
 
 #include "check.hxx"
-#include "compat.hxx"
 #include "plugin.hxx"
 
 /*
@@ -39,13 +38,7 @@ private:
     StringRef getFilename(SourceLocation loc);
 };
 
-bool BaseCheckNotTestFixtureSubclass(
-    const CXXRecordDecl *BaseDefinition
-#if CLANG_VERSION < 30800
-    , void *
-#endif
-    )
-{
+bool BaseCheckNotTestFixtureSubclass(const CXXRecordDecl *BaseDefinition) {
     if (loplugin::TypeCheck(BaseDefinition).Class("TestFixture").Namespace("CppUnit").GlobalNamespace()) {
         return false;
     }
@@ -58,7 +51,7 @@ bool isDerivedFromTestFixture(const CXXRecordDecl *decl) {
     if (// not sure what hasAnyDependentBases() does,
         // but it avoids classes we don't want, e.g. WeakAggComponentImplHelper1
         !decl->hasAnyDependentBases() &&
-        !compat::forallBases(*decl, BaseCheckNotTestFixtureSubclass, nullptr, true)) {
+        !decl->forallBases(BaseCheckNotTestFixtureSubclass, true)) {
         return true;
     }
     return false;
diff --git a/compilerplugins/clang/store/removevirtuals.cxx b/compilerplugins/clang/store/removevirtuals.cxx
index 6ed3dd60e191..e44cb738629e 100644
--- a/compilerplugins/clang/store/removevirtuals.cxx
+++ b/compilerplugins/clang/store/removevirtuals.cxx
@@ -11,7 +11,6 @@
 #include <string>
 #include <iostream>
 #include "plugin.hxx"
-#include "compat.hxx"
 #include <sys/mman.h>
 #include <sys/types.h>
 #include <fcntl.h>
@@ -75,7 +74,7 @@ std::string niceName(const CXXMethodDecl* functionDecl)
 {
     std::string s =
            functionDecl->getParent()->getQualifiedNameAsString() + "::"
-           + compat::getReturnType(*functionDecl).getAsString() + "-"
+           + functionDecl->getReturnType().getAsString() + "-"
            + functionDecl->getNameAsString() + "(";
     for (const ParmVarDecl *pParmVarDecl : functionDecl->params()) {
         s += pParmVarDecl->getType().getAsString();
diff --git a/compilerplugins/clang/store/returnbyref.cxx b/compilerplugins/clang/store/returnbyref.cxx
index 9fa66131a880..51723c0f40a4 100644
--- a/compilerplugins/clang/store/returnbyref.cxx
+++ b/compilerplugins/clang/store/returnbyref.cxx
@@ -10,7 +10,6 @@
 #include <string>
 #include <set>
 
-#include "compat.hxx"
 #include "plugin.hxx"
 
 // Find places where we are returning a pointer to something, where we can be returning a reference.
@@ -55,7 +54,7 @@ bool ReturnByRef::VisitCXXMethodDecl(const CXXMethodDecl * functionDecl) {
     if (isInUnoIncludeFile(functionDecl)) {
         return true;
     }
-    QualType t1 { compat::getReturnType(*functionDecl) };
+    QualType t1 { functionDecl->getReturnType() };
     if (!t1->isPointerType()) {
         return true;
     }
diff --git a/compilerplugins/clang/test/datamembershadow.cxx b/compilerplugins/clang/test/datamembershadow.cxx
index 5965421360ec..a11a7cc51c65 100644
--- a/compilerplugins/clang/test/datamembershadow.cxx
+++ b/compilerplugins/clang/test/datamembershadow.cxx
@@ -11,8 +11,6 @@
 
 #include <config_clang.h>
 
-// '#if CLANG_VERSION >= 30800' covers large parts of compilerplugins/clang/datamembershadow.cxx
-#if CLANG_VERSION >= 30800
 struct Bar {
     int x; // expected-note {{superclass member here [loplugin:datamembershadow]}}
 };
@@ -20,8 +18,5 @@ struct Bar {
 struct Foo : public Bar {
     int x; // expected-error {{data member x is shadowing member in superclass, through inheritance path Foo->Bar [loplugin:datamembershadow]}}
 };
-#else
-// expected-no-diagnostics
-#endif
 
 /* 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 336c7712a95f..f912e43009bb 100644
--- a/compilerplugins/clang/unnecessaryoverride.cxx
+++ b/compilerplugins/clang/unnecessaryoverride.cxx
@@ -14,7 +14,6 @@
 #include <set>
 
 #include <clang/AST/CXXInheritance.h>
-#include "compat.hxx"
 #include "plugin.hxx"
 
 /**
@@ -102,12 +101,7 @@ public:
 
 private:
     const CXXMethodDecl * findOverriddenOrSimilarMethodInSuperclasses(const CXXMethodDecl *);
-    bool BaseCheckCallback(
-        const CXXRecordDecl *BaseDefinition
-    #if CLANG_VERSION < 30800
-        , void *
-    #endif
-        );
+    bool BaseCheckCallback(const CXXRecordDecl *BaseDefinition);
 };
 
 bool UnnecessaryOverride::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
@@ -277,8 +271,8 @@ bool UnnecessaryOverride::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
         }
     }
 
-    if (compat::getReturnType(*methodDecl).getCanonicalType()
-        != compat::getReturnType(*overriddenMethodDecl).getCanonicalType())
+    if (methodDecl->getReturnType().getCanonicalType()
+        != overriddenMethodDecl->getReturnType().getCanonicalType())
     {
         return true;
     }
@@ -290,7 +284,7 @@ bool UnnecessaryOverride::VisitCXXMethodDecl(const CXXMethodDecl* methodDecl)
         return true;
 
     const CXXMemberCallExpr* callExpr = nullptr;
-    if (compat::getReturnType(*methodDecl).getCanonicalType()->isVoidType())
+    if (methodDecl->getReturnType().getCanonicalType()->isVoidType())
     {
         if (auto const e = dyn_cast<Expr>(*compoundStmt->body_begin())) {
             callExpr = dyn_cast<CXXMemberCallExpr>(e->IgnoreImplicit()->IgnoreParens());
@@ -395,9 +389,6 @@ const CXXMethodDecl* UnnecessaryOverride::findOverriddenOrSimilarMethodInSupercl
         return nullptr;
     }
 
-#if CLANG_VERSION < 30800
-        return nullptr;
-#else
     std::vector<const CXXMethodDecl*> maSimilarMethods;
 
     auto BaseMatchesCallback = [&](const CXXBaseSpecifier *cxxBaseSpecifier, CXXBasePath& )
@@ -425,8 +416,8 @@ const CXXMethodDecl* UnnecessaryOverride::findOverriddenOrSimilarMethodInSupercl
             {
                 continue;
             }
-            if (compat::getReturnType(*methodDecl).getCanonicalType()
-                != compat::getReturnType(*baseMethod).getCanonicalType())
+            if (methodDecl->getReturnType().getCanonicalType()
+                != baseMethod->getReturnType().getCanonicalType())
             {
                 continue;
             }
@@ -454,7 +445,6 @@ const CXXMethodDecl* UnnecessaryOverride::findOverriddenOrSimilarMethodInSupercl
         return maSimilarMethods[0];
     }
     return nullptr;
-#endif
 }
 
 
diff --git a/compilerplugins/clang/unnecessaryvirtual.cxx b/compilerplugins/clang/unnecessaryvirtual.cxx
index 9ff389d1290e..f9283e3a1754 100644
--- a/compilerplugins/clang/unnecessaryvirtual.cxx
+++ b/compilerplugins/clang/unnecessaryvirtual.cxx
@@ -84,7 +84,7 @@ std::string niceName(const CXXMethodDecl* functionDecl)
 {
     std::string s =
            functionDecl->getParent()->getQualifiedNameAsString() + "::"
-           + compat::getReturnType(*functionDecl).getAsString() + "-"
+           + functionDecl->getReturnType().getAsString() + "-"
            + functionDecl->getNameAsString() + "(";
     for (const ParmVarDecl *pParmVarDecl : compat::parameters(*functionDecl)) {
         s += pParmVarDecl->getType().getAsString();
diff --git a/compilerplugins/clang/unusedmethods.cxx b/compilerplugins/clang/unusedmethods.cxx
index 9122e3565d54..6ea3da69716b 100644
--- a/compilerplugins/clang/unusedmethods.cxx
+++ b/compilerplugins/clang/unusedmethods.cxx
@@ -136,11 +136,8 @@ MyFuncInfo UnusedMethods::niceName(const FunctionDecl* functionDecl)
         functionDecl = functionDecl->getInstantiatedFromMemberFunction();
     else if (functionDecl->getClassScopeSpecializationPattern())
         functionDecl = functionDecl->getClassScopeSpecializationPattern();
-// workaround clang-3.5 issue
-#if CLANG_VERSION >= 30600
     else if (functionDecl->getTemplateInstantiationPattern())
         functionDecl = functionDecl->getTemplateInstantiationPattern();
-#endif
 
     MyFuncInfo aInfo;
     switch (functionDecl->getAccess())
@@ -151,7 +148,7 @@ MyFuncInfo UnusedMethods::niceName(const FunctionDecl* functionDecl)
     default: aInfo.access = "unknown"; break;
     }
     if (!isa<CXXConstructorDecl>(functionDecl)) {
-        aInfo.returnType = compat::getReturnType(*functionDecl).getCanonicalType().getAsString();
+        aInfo.returnType = functionDecl->getReturnType().getCanonicalType().getAsString();
     } else {
         aInfo.returnType = "";
     }
@@ -262,7 +259,7 @@ gotfunc:
     }
 
     // Now do the checks necessary for the "unused return value" analysis
-    if (compat::getReturnType(*calleeFunctionDecl)->isVoidType()) {
+    if (calleeFunctionDecl->getReturnType()->isVoidType()) {
         return true;
     }
     if (!parent) {
diff --git a/compilerplugins/clang/unusedmethodsremove.cxx b/compilerplugins/clang/unusedmethodsremove.cxx
index 3d3886ace0db..33c7ee7a1fec 100644
--- a/compilerplugins/clang/unusedmethodsremove.cxx
+++ b/compilerplugins/clang/unusedmethodsremove.cxx
@@ -76,7 +76,7 @@ UnusedMethodsRemove::~UnusedMethodsRemove()
 std::string niceName(const CXXMethodDecl* functionDecl)
 {
     std::string s =
-        compat::getReturnType(*functionDecl).getCanonicalType().getAsString()
+        functionDecl->getReturnType().getCanonicalType().getAsString()
         + " " + functionDecl->getParent()->getQualifiedNameAsString()
         + "::" + functionDecl->getNameAsString()
         + "(";
diff --git a/compilerplugins/clang/vclwidgets.cxx b/compilerplugins/clang/vclwidgets.cxx
index 0f966708bc2d..c2cfeaa08095 100644
--- a/compilerplugins/clang/vclwidgets.cxx
+++ b/compilerplugins/clang/vclwidgets.cxx
@@ -12,7 +12,6 @@
 #include <iostream>
 
 #include "plugin.hxx"
-#include "compat.hxx"
 #include "check.hxx"
 #include "clang/AST/CXXInheritance.h"
 
@@ -55,13 +54,7 @@ private:
 
 #define BASE_REF_COUNTED_CLASS "VclReferenceBase"
 
-bool BaseCheckNotWindowSubclass(
-    const CXXRecordDecl *BaseDefinition
-#if CLANG_VERSION < 30800
-    , void *
-#endif
-    )
-{
+bool BaseCheckNotWindowSubclass(const CXXRecordDecl *BaseDefinition) {
     return !loplugin::DeclCheck(BaseDefinition).Class(BASE_REF_COUNTED_CLASS)
         .GlobalNamespace();
 }
@@ -80,7 +73,7 @@ bool isDerivedFromVclReferenceBase(const CXXRecordDecl *decl) {
     if (// not sure what hasAnyDependentBases() does,
         // but it avoids classes we don't want, e.g. WeakAggComponentImplHelper1
         !decl->hasAnyDependentBases() &&
-        !compat::forallBases(*decl, BaseCheckNotWindowSubclass, nullptr, true)) {
+        !decl->forallBases(BaseCheckNotWindowSubclass, true)) {
         return true;
     }
     return false;
diff --git a/configure.ac b/configure.ac
index 0689111ae700..4e00de777ec4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5921,8 +5921,7 @@ if test "$GCC" = "yes" -o "$COM_IS_CLANG" = TRUE; then
         ], [AC_MSG_RESULT([no])])
     AC_LANG_POP([C++])
 
-    dnl Available in GCC 4.9 and at least in Clang 3.4 (which is the baseline
-    dnl for at least --enable-compiler-plugins according to README.md):
+    dnl Available in GCC 4.9 and at least since Clang 3.4:
     AC_MSG_CHECKING([whether $CXX supports __attribute__((warn_unused))])
     AC_LANG_PUSH([C++])
     save_CXXFLAGS=$CXXFLAGS
@@ -6419,6 +6418,13 @@ if test "$COM_IS_CLANG" = "TRUE"; then
     else
         compiler_plugins=no
     fi
+    if test "$compiler_plugins" != no -a "$CLANGVER" -lt 30800; then
+        if test "$compiler_plugins" = yes; then
+            AC_MSG_ERROR([Clang $CLANGVER is too old to build compiler plugins; need >= 3.8.0.])
+        else
+            compiler_plugins=no
+        fi
+    fi
     if test "$compiler_plugins" != "no"; then
         dnl The prefix where Clang resides, override to where Clang resides if
         dnl using a source build: