diff --git a/cmake/FindClang.cmake b/cmake/FindClang.cmake
index ad085d48..6bfac108 100644
--- a/cmake/FindClang.cmake
+++ b/cmake/FindClang.cmake
@@ -69,11 +69,15 @@ set(_Clang_REQUIRED_VARS Clang_LIBRARY Clang_INCLUDE_DIR Clang_EXECUTABLE
                          LLVM_INCLUDE_DIR LLVM_BUILD_INCLUDE_DIR)
 
 _Clang_find_library(Clang_LIBRARY clang)
+_Clang_find_add_library(clangAST)
+_Clang_find_add_library(clangLex)
 _Clang_find_add_library(clangDriver)
 _Clang_find_add_library(clangBasic)
 if(USE_SHARED_LLVM)
   _Clang_find_add_library(LLVM)
 else()
+  _Clang_find_add_library(LLVMCore)
+  _Clang_find_add_library(LLVMBinaryFormat)
   _Clang_find_add_library(LLVMOption)
   _Clang_find_add_library(LLVMSupport)
   _Clang_find_add_library(LLVMDemangle)
diff --git a/src/config.cc b/src/config.cc
index 102d05a6..27fac9c4 100644
--- a/src/config.cc
+++ b/src/config.cc
@@ -1,4 +1,4 @@
 #include "config.h"
 
-std::unique_ptr<Config> g_config;
+Config* g_config;
 thread_local int g_thread_id;
diff --git a/src/config.h b/src/config.h
index 58946bac..114f0c66 100644
--- a/src/config.h
+++ b/src/config.h
@@ -2,7 +2,6 @@
 
 #include "serializer.h"
 
-#include <memory>
 #include <string>
 
 /*
@@ -192,6 +191,9 @@ struct Config {
     std::vector<std::string> whitelist;
   } index;
 
+  // Disable semantic highlighting for files larger than the size.
+  int64_t largeFileSize = 2 * 1024 * 1024;
+
   struct WorkspaceSymbol {
     int caseSensitivity = 1;
     // Maximum workspace search results.
@@ -252,8 +254,9 @@ MAKE_REFLECT_STRUCT(Config,
                     diagnostics,
                     highlight,
                     index,
+                    largeFileSize,
                     workspaceSymbol,
                     xref);
 
-extern std::unique_ptr<Config> g_config;
+extern Config* g_config;
 thread_local extern int g_thread_id;
diff --git a/src/indexer.cc b/src/indexer.cc
index de393f9c..e714a6c2 100644
--- a/src/indexer.cc
+++ b/src/indexer.cc
@@ -5,7 +5,9 @@
 #include "serializer.h"
 #include "type_printer.h"
 
+#include <clang/AST/AST.h>
 #include <llvm/Support/Timer.h>
+using namespace clang;
 using namespace llvm;
 
 #include <assert.h>
@@ -151,26 +153,24 @@ lsSymbolKind GetSymbolKind(CXIdxEntityKind kind) {
   return lsSymbolKind::Unknown;
 }
 
-StorageClass GetStorageClass(CX_StorageClass storage) {
+StorageClass GetStorageC(CX_StorageClass storage) {
   switch (storage) {
+    default:
     case CX_SC_Invalid:
     case CX_SC_OpenCLWorkGroupLocal:
-      return StorageClass::Invalid;
     case CX_SC_None:
-      return StorageClass::None;
+      return SC_None;
     case CX_SC_Extern:
-      return StorageClass::Extern;
+      return SC_Extern;
     case CX_SC_Static:
-      return StorageClass::Static;
+      return SC_Static;
     case CX_SC_PrivateExtern:
-      return StorageClass::PrivateExtern;
+      return SC_PrivateExtern;
     case CX_SC_Auto:
-      return StorageClass::Auto;
+      return SC_Auto;
     case CX_SC_Register:
-      return StorageClass::Register;
+      return SC_Register;
   }
-
-  return StorageClass::None;
 }
 
 // Caches all instances of constructors, regardless if they are indexed or not.
@@ -583,7 +583,7 @@ void SetVarDetail(IndexVar& var,
     type_name = "lambda";
   if (g_config->index.comments)
     def.comments = cursor.get_comments();
-  def.storage = GetStorageClass(clang_Cursor_getStorageClass(cursor.cx_cursor));
+  def.storage = GetStorageC(clang_Cursor_getStorageClass(cursor.cx_cursor));
 
   // TODO how to make PrettyPrint'ed variable name qualified?
 #if 0 && CINDEX_HAVE_PRETTY
@@ -1526,7 +1526,7 @@ void OnIndexDeclaration(CXClientData client_data, const CXIdxDeclInfo* decl) {
         func.def.comments = cursor.get_comments();
       func.def.kind = GetSymbolKind(decl->entityInfo->kind);
       func.def.storage =
-          GetStorageClass(clang_Cursor_getStorageClass(decl->cursor));
+          GetStorageC(clang_Cursor_getStorageClass(decl->cursor));
 
       // We don't actually need to know the return type, but we need to mark it
       // as an interesting usage.
@@ -1536,11 +1536,13 @@ void OnIndexDeclaration(CXClientData client_data, const CXIdxDeclInfo* decl) {
       // Add definition or declaration. This is a bit tricky because we treat
       // template specializations as declarations, even though they are
       // technically definitions.
-      // TODO: Support multiple function definitions, which is common for
-      //       template specializations.
-      if (decl->isDefinition && !is_template_specialization) {
-        // assert(!func->def.spell);
-        // assert(!func->def.extent);
+      bool is_def = decl->isDefinition;
+      if (!is_def) {
+        auto* D = static_cast<const Decl*>(decl->cursor.data[0]);
+        auto* Method = dyn_cast_or_null<CXXMethodDecl>(D->getAsFunction());
+        is_def = Method && (Method->isDefaulted() || Method->isPure());
+      }
+      if (is_def && !is_template_specialization) {
         func.def.spell = SetUse(db, spell, sem_parent, Role::Definition);
         func.def.extent = SetUse(db, extent, lex_parent, Role::None);
       } else {
diff --git a/src/indexer.h b/src/indexer.h
index 70619e9d..156f7c66 100644
--- a/src/indexer.h
+++ b/src/indexer.h
@@ -12,6 +12,7 @@
 #include "symbol.h"
 #include "utils.h"
 
+#include <clang/Basic/Specifiers.h>
 #include <llvm/ADT/StringMap.h>
 
 #include <stdint.h>
@@ -62,6 +63,8 @@ struct Use : Reference {
 void Reflect(Reader& visitor, Reference& value);
 void Reflect(Writer& visitor, Reference& value);
 
+MAKE_REFLECT_TYPE_PROXY2(clang::StorageClass, uint8_t);
+
 template <typename D>
 struct NameMixin {
   std::string_view Name(bool qualified) const {
@@ -99,7 +102,7 @@ struct FuncDef : NameMixin<FuncDef> {
   int16_t short_name_offset = 0;
   int16_t short_name_size = 0;
   lsSymbolKind kind = lsSymbolKind::Unknown;
-  StorageClass storage = StorageClass::Invalid;
+  clang::StorageClass storage = clang::SC_None;
 
   std::vector<Usr> GetBases() const { return bases; }
   bool operator==(const FuncDef& o) const {
@@ -213,11 +216,11 @@ struct VarDef : NameMixin<VarDef> {
   lsSymbolKind kind = lsSymbolKind::Unknown;
   // Note a variable may have instances of both |None| and |Extern|
   // (declaration).
-  StorageClass storage = StorageClass::Invalid;
+  clang::StorageClass storage = clang::SC_None;
 
   bool is_local() const {
     return spell && spell->kind != SymbolKind::File &&
-           storage == StorageClass::None;
+           storage == clang::SC_None;
   }
 
   std::vector<Usr> GetBases() const { return {}; }
diff --git a/src/message_handler.cc b/src/message_handler.cc
index 168fa605..60aea634 100644
--- a/src/message_handler.cc
+++ b/src/message_handler.cc
@@ -6,6 +6,8 @@
 #include "pipeline.hh"
 using namespace ccls;
 
+using namespace clang;
+
 #include <algorithm>
 
 MAKE_HASHABLE(SymbolIdx, t.usr, t.kind);
@@ -187,10 +189,11 @@ void EmitInactiveLines(WorkingFile* working_file,
 
 void EmitSemanticHighlighting(DB* db,
                               SemanticHighlightSymbolCache* semantic_cache,
-                              WorkingFile* working_file,
+                              WorkingFile* wfile,
                               QueryFile* file) {
   assert(file->def);
-  if (!semantic_cache->match_->IsMatch(file->def->path))
+  if (wfile->buffer_content.size() > g_config->largeFileSize ||
+      !semantic_cache->match_->IsMatch(file->def->path))
     return;
   auto semantic_cache_for_file =
       semantic_cache->GetCacheForFile(file->def->path);
@@ -202,7 +205,7 @@ void EmitSemanticHighlighting(DB* db,
     std::string_view detailed_name;
     lsSymbolKind parent_kind = lsSymbolKind::Unknown;
     lsSymbolKind kind = lsSymbolKind::Unknown;
-    StorageClass storage = StorageClass::Invalid;
+    StorageClass storage = SC_None;
     // This switch statement also filters out symbols that are not highlighted.
     switch (sym.kind) {
       case SymbolKind::Func: {
@@ -237,9 +240,9 @@ void EmitSemanticHighlighting(DB* db,
             detailed_name.substr(0, detailed_name.find('<'));
         int16_t start_line = sym.range.start.line;
         int16_t start_col = sym.range.start.column;
-        if (start_line < 0 || start_line >= working_file->index_lines.size())
+        if (start_line < 0 || start_line >= wfile->index_lines.size())
           continue;
-        std::string_view line = working_file->index_lines[start_line];
+        std::string_view line = wfile->index_lines[start_line];
         sym.range.end.line = start_line;
         if (!(start_col + concise_name.size() <= line.size() &&
               line.compare(start_col, concise_name.size(), concise_name) == 0))
@@ -280,7 +283,7 @@ void EmitSemanticHighlighting(DB* db,
         continue;  // applies to for loop
     }
 
-    std::optional<lsRange> loc = GetLsRange(working_file, sym.range);
+    std::optional<lsRange> loc = GetLsRange(wfile, sym.range);
     if (loc) {
       auto it = grouped_symbols.find(sym);
       if (it != grouped_symbols.end()) {
@@ -339,7 +342,7 @@ void EmitSemanticHighlighting(DB* db,
 
   // Publish.
   Out_CclsPublishSemanticHighlighting out;
-  out.params.uri = lsDocumentUri::FromPath(working_file->filename);
+  out.params.uri = lsDocumentUri::FromPath(wfile->filename);
   for (auto& entry : grouped_symbols)
     if (entry.second.ranges.size())
       out.params.symbols.push_back(entry.second);
diff --git a/src/message_handler.h b/src/message_handler.h
index f73dc483..64e73e57 100644
--- a/src/message_handler.h
+++ b/src/message_handler.h
@@ -63,7 +63,7 @@ struct Out_CclsPublishSemanticHighlighting
     int stableId = 0;
     lsSymbolKind parentKind;
     lsSymbolKind kind;
-    StorageClass storage;
+    clang::StorageClass storage;
     std::vector<lsRange> ranges;
   };
   struct Params {
diff --git a/src/messages/ccls_call_hierarchy.cc b/src/messages/ccls_call_hierarchy.cc
index bff5ca84..92267d83 100644
--- a/src/messages/ccls_call_hierarchy.cc
+++ b/src/messages/ccls_call_hierarchy.cc
@@ -95,7 +95,7 @@ bool Expand(MessageHandler* m,
   entry->numChildren = 0;
   if (!def)
     return false;
-  auto handle = [&](Use use, CallType call_type) {
+  auto handle = [&](Use use, CallType call_type1) {
     entry->numChildren++;
     if (levels > 0) {
       Out_CclsCallHierarchy::Entry entry1;
@@ -103,7 +103,7 @@ bool Expand(MessageHandler* m,
       entry1.usr = use.usr;
       if (auto loc = GetLsLocation(m->db, m->working_files, use))
         entry1.location = *loc;
-      entry1.callType = call_type;
+      entry1.callType = call_type1;
       if (Expand(m, &entry1, callee, call_type, qualified, levels - 1))
         entry->children.push_back(std::move(entry1));
     }
diff --git a/src/messages/initialize.cc b/src/messages/initialize.cc
index 4045eda8..02d6c1db 100644
--- a/src/messages/initialize.cc
+++ b/src/messages/initialize.cc
@@ -438,9 +438,9 @@ struct Handler_Initialize : BaseMessageHandler<In_InitializeRequest> {
 
     {
       if (params.initializationOptions)
-        g_config = std::make_unique<Config>(*params.initializationOptions);
+        g_config = new Config(*params.initializationOptions);
       else
-        g_config = std::make_unique<Config>();
+        g_config = new Config;
       rapidjson::Document reader;
       reader.Parse(g_init_options.c_str());
       if (!reader.HasParseError()) {
diff --git a/src/messages/text_document_document_symbol.cc b/src/messages/text_document_document_symbol.cc
index 959328e3..212994cd 100644
--- a/src/messages/text_document_document_symbol.cc
+++ b/src/messages/text_document_document_symbol.cc
@@ -2,6 +2,7 @@
 #include "pipeline.hh"
 #include "query_utils.h"
 using namespace ccls;
+using namespace clang;
 
 namespace {
 MethodType kMethodType = "textDocument/documentSymbol";
@@ -51,9 +52,8 @@ struct Handler_TextDocumentDocumentSymbol
         if (!def || !def->spell)
           continue;
         // Ignore local variables.
-        if (def->spell->kind == SymbolKind::Func &&
-            def->storage != StorageClass::Static &&
-            def->storage != StorageClass::Extern)
+        if (def->spell->kind == SymbolKind::Func && def->storage != SC_Static &&
+            def->storage != SC_Extern)
           continue;
       }
 
diff --git a/src/project.cc b/src/project.cc
index 74c82080..0ff3193a 100644
--- a/src/project.cc
+++ b/src/project.cc
@@ -450,7 +450,9 @@ TEST_SUITE("Project") {
   void CheckFlags(const std::string& directory, const std::string& file,
                   std::vector<std::string> raw,
                   std::vector<std::string> expected) {
-    g_config = std::make_unique<Config>();
+    if (g_config)
+      delete g_config;
+    g_config = new Config;
     g_config->clang.resourceDir = "/w/resource_dir/";
     ProjectConfig project;
     project.project_dir = "/w/c/s/";
@@ -536,7 +538,9 @@ TEST_SUITE("Project") {
   }
 
   TEST_CASE("Directory extraction") {
-    g_config = std::make_unique<Config>();
+    if (g_config)
+      delete g_config;
+    g_config = new Config;
     ProjectConfig config;
     config.project_dir = "/w/c/s/";
 
diff --git a/src/symbol.h b/src/symbol.h
index 13b9f39a..3a79ba07 100644
--- a/src/symbol.h
+++ b/src/symbol.h
@@ -8,27 +8,6 @@
 enum class SymbolKind : uint8_t { Invalid, File, Type, Func, Var };
 MAKE_REFLECT_TYPE_PROXY(SymbolKind);
 
-// clang/Basic/Specifiers.h clang::StorageClass
-enum class StorageClass : uint8_t {
-  // In |CX_StorageClass| but not in |clang::StorageClass|
-  // e.g. non-type template parameters
-  Invalid,
-
-  // These are legal on both functions and variables.
-  // e.g. global functions/variables, local variables
-  None,
-  Extern,
-  Static,
-  // e.g. |__private_extern__ int a;|
-  PrivateExtern,
-
-  // These are only legal on variables.
-  // e.g. explicit |auto int a;|
-  Auto,
-  Register
-};
-MAKE_REFLECT_TYPE_PROXY(StorageClass);
-
 enum class Role : uint16_t {
   None = 0,
   Declaration = 1 << 0,
diff --git a/src/test.cc b/src/test.cc
index f3001f6c..c9dff5cf 100644
--- a/src/test.cc
+++ b/src/test.cc
@@ -288,7 +288,7 @@ bool RunIndexTests(const std::string& filter_path, bool enable_update) {
         flags.push_back(path);
 
         // Run test.
-        g_config = std::make_unique<Config>();
+        g_config = new Config;
         VFS vfs;
         auto dbs = index.Index(&vfs, path, flags, {});