diff --git a/src/indexer.cc b/src/indexer.cc
index f4e9be8b..443e0c8e 100644
--- a/src/indexer.cc
+++ b/src/indexer.cc
@@ -37,6 +37,7 @@ limitations under the License.
 #include <unordered_set>
 
 using namespace clang;
+using namespace ccls::log;
 
 namespace ccls {
 namespace {
@@ -525,8 +526,9 @@ public:
     }
     auto i = name.find(short_name);
     if (short_name.size())
-      while (i != std::string::npos && ((i && isIdentifierBody(name[i - 1])) ||
-                                        isIdentifierBody(name[i + short_name.size()])))
+      while (i != std::string::npos &&
+             ((i && isIdentifierBody(name[i - 1])) ||
+              isIdentifierBody(name[i + short_name.size()])))
         i = name.find(short_name, i + short_name.size());
     if (i == std::string::npos) {
       // e.g. operator type-parameter-1
@@ -751,8 +753,8 @@ public:
       switch (D->getKind()) {
       case Decl::CXXConversion: // *operator* int => *operator int*
       case Decl::CXXDestructor: // *~*A => *~A*
-      case Decl::CXXMethod: // *operator*= => *operator=*
-      case Decl::Function: // operator delete
+      case Decl::CXXMethod:     // *operator*= => *operator=*
+      case Decl::Function:      // operator delete
         if (Loc.isFileID()) {
           SourceRange R =
               cast<FunctionDecl>(OrigD)->getNameInfo().getSourceRange();
@@ -794,9 +796,9 @@ public:
     switch (kind) {
     case Kind::Invalid:
       if (ls_kind == SymbolKind::Unknown)
-        LOG_S(INFO) << "Unhandled " << int(D->getKind()) << " "
-                    << info->qualified << " in " << db->path << ":"
-                    << (loc.start.line + 1) << ":" << (loc.start.column + 1);
+        if (auto v = Verbosity::INFO; LogRequire(v))
+          Log(v, "Unhandled ", int(D->getKind()), " ", info->qualified, " in ",
+              db->path, ":", (loc.start.line + 1), ":", (loc.start.column + 1));
       return true;
     case Kind::File:
       return true;
@@ -952,12 +954,14 @@ public:
       if (auto *RD = dyn_cast<RecordDecl>(D)) {
         if (type->def.detailed_name[0] == '\0' && info->short_name.empty()) {
           StringRef Tag;
+          // clang-format off
           switch (RD->getTagKind()) {
           case TTK_Struct: Tag = "struct"; break;
           case TTK_Interface: Tag = "__interface"; break;
           case TTK_Union: Tag = "union"; break;
           case TTK_Class: Tag = "class"; break;
           case TTK_Enum: Tag = "enum"; break;
+            // clang-format on
           }
           if (TypedefNameDecl *TD = RD->getTypedefNameForAnonDecl()) {
             StringRef Name = TD->getName();
@@ -1220,7 +1224,8 @@ Index(SemaManager *manager, WorkingFiles *wfiles, VFS *vfs,
       bool &ok) {
   ok = true;
   auto PCH = std::make_shared<PCHContainerOperations>();
-  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS = llvm::vfs::getRealFileSystem();
+  llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS =
+      llvm::vfs::getRealFileSystem();
   std::shared_ptr<CompilerInvocation> CI =
       BuildCompilerInvocation(main, args, FS);
   // e.g. .s
@@ -1288,12 +1293,14 @@ Index(SemaManager *manager, WorkingFiles *wfiles, VFS *vfs,
       ok = true;
     };
     if (!CRC.RunSafely(parse)) {
-      LOG_S(ERROR) << "clang crashed for " << main;
+      if (auto v = Verbosity::ERROR; LogRequire(v))
+        Log(v, "clang crashed for ", main);
       return {};
     }
   }
   if (!ok) {
-    LOG_S(ERROR) << "failed to index " << main;
+    if (auto v = Verbosity::ERROR; LogRequire(v))
+      Log(v, "failed to index ", main);
     return {};
   }
   for (auto &Buf : Bufs)
diff --git a/src/log.cc b/src/log.cc
index 3e2b5592..ea909410 100644
--- a/src/log.cc
+++ b/src/log.cc
@@ -56,11 +56,13 @@ Message::Message(Verbosity verbosity, const char *file, int line)
   stream_ << ' ';
   // clang-format off
   switch (verbosity_) {
-    case Verbosity_FATAL: stream_ << 'F'; break;
-    case Verbosity_ERROR: stream_ << 'E'; break;
-    case Verbosity_WARNING: stream_ << 'W'; break;
-    case Verbosity_INFO: stream_ << 'I'; break;
-    default: stream_ << "V(" << int(verbosity_) << ')';
+    case Verbosity::FATAL: stream_ << 'F'; break;
+    case Verbosity::ERROR: stream_ << 'E'; break;
+    case Verbosity::WARNING: stream_ << 'W'; break;
+    case Verbosity::INFO: stream_ << 'I'; break;
+    case Verbosity::DEBUG: stream_ << 'D'; break;
+    case Verbosity::VERBOSE: stream_ << 'V'; break;
+    default: stream_ << "V(" << +verbosity_ << ')';
   }
   // clang-format on
   stream_ << ' ';
@@ -73,7 +75,7 @@ Message::~Message() {
   stream_ << '\n';
   fputs(stream_.str().c_str(), file);
   fflush(file);
-  if (verbosity_ == Verbosity_FATAL)
+  if (verbosity_ == Verbosity::FATAL)
     abort();
 }
 } // namespace ccls::log
diff --git a/src/log.hh b/src/log.hh
index 5d06d41a..46ae6582 100644
--- a/src/log.hh
+++ b/src/log.hh
@@ -1,41 +1,45 @@
 #pragma once
 
-#include <stdio.h>
 #include <sstream>
+#include <stdio.h>
+#include <string>
+#include <type_traits>
 
 namespace ccls::log {
-extern FILE* file;
+extern FILE *file;
 
-struct Voidify {
-  void operator&(const std::ostream&) {}
+enum class Verbosity : signed {
+  FATAL = -3,
+  ERROR = -2,
+  WARNING = -1,
+  INFO = 0,
+  DEBUG = 1,
+  VERBOSE = 2
 };
+template <typename T, typename UT = std::underlying_type_t<T>>
+constexpr auto operator+(T e) noexcept
+    -> std::enable_if_t<std::is_enum_v<T>, UT> {
+  return static_cast<UT>(e);
+}
 
-enum Verbosity {
-  Verbosity_FATAL = -3,
-  Verbosity_ERROR = -2,
-  Verbosity_WARNING = -1,
-  Verbosity_INFO = 0,
-};
 extern Verbosity verbosity;
 
 struct Message {
   std::stringstream stream_;
-  int verbosity_;
+  Verbosity verbosity_;
 
-  Message(Verbosity verbosity, const char* file, int line);
+  Message(Verbosity verbosity, const char *file, int line);
   ~Message();
 };
+
+template <typename... Args> inline void Log(Verbosity v, Args const &... args) {
+  (Message(v, __FILE__, __LINE__).stream_ << ... << args);
 }
 
-#define LOG_IF(v, cond)            \
-  !(cond) ? void(0)                \
-          : ccls::log::Voidify() & \
-                ccls::log::Message(v, __FILE__, __LINE__).stream_
-#define LOG_S(v)                   \
-  LOG_IF(ccls::log::Verbosity_##v, \
-         ccls::log::Verbosity_##v <= ccls::log::verbosity)
-#define LOG_IF_S(v, cond)          \
-  LOG_IF(ccls::log::Verbosity_##v, \
-         (cond) && ccls::log::Verbosity_##v <= ccls::log::verbosity)
-#define LOG_V_ENABLED(v) (v <= ccls::log::verbosity)
-#define LOG_V(v) LOG_IF(ccls::log::Verbosity(v), LOG_V_ENABLED(v))
+// XXX: According to CWG 1766, static_cast invalid(out of range) value to enum
+// class is UB
+bool inline LogRequire(Verbosity v) { return +v <= +verbosity; }
+
+// ADL
+bool inline LogIf(Verbosity v, bool cond) { return cond && LogRequire(v); }
+} // namespace ccls::log
diff --git a/src/lsp.cc b/src/lsp.cc
index 5c56f324..738f278a 100644
--- a/src/lsp.cc
+++ b/src/lsp.cc
@@ -21,6 +21,7 @@ limitations under the License.
 
 #include <algorithm>
 #include <stdio.h>
+using namespace ccls::log;
 
 namespace ccls {
 void Reflect(JsonReader &vis, RequestId &v) {
@@ -103,9 +104,9 @@ void DocumentUri::SetPath(const std::string &path) {
 
 std::string DocumentUri::GetPath() const {
   if (raw_uri.compare(0, 7, "file://")) {
-    LOG_S(WARNING)
-        << "Received potentially bad URI (not starting with file://): "
-        << raw_uri;
+    if (auto v = Verbosity::WARNING; LogRequire(v))
+      Log(v, "Received potentially bad URI (not starting with file://): ",
+          raw_uri);
     return raw_uri;
   }
   std::string ret;
diff --git a/src/messages/initialize.cc b/src/messages/initialize.cc
index c0344a34..977b0406 100644
--- a/src/messages/initialize.cc
+++ b/src/messages/initialize.cc
@@ -13,7 +13,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ==============================================================================*/
 
-#include "sema_manager.hh"
 #include "filesystem.hh"
 #include "include_complete.hh"
 #include "log.hh"
@@ -21,6 +20,7 @@ limitations under the License.
 #include "pipeline.hh"
 #include "platform.hh"
 #include "project.hh"
+#include "sema_manager.hh"
 #include "working_files.hh"
 
 #include <llvm/ADT/Twine.h>
@@ -29,12 +29,13 @@ limitations under the License.
 #include <rapidjson/document.h>
 #include <rapidjson/writer.h>
 
-#include <stdlib.h>
 #include <stdexcept>
+#include <stdlib.h>
 #include <thread>
 
 namespace ccls {
 using namespace llvm;
+using namespace ccls::log;
 
 extern std::vector<std::string> g_init_options;
 
@@ -184,7 +185,8 @@ REFLECT_STRUCT(TextDocumentClientCap::DocumentSymbol,
                hierarchicalDocumentSymbolSupport);
 REFLECT_STRUCT(TextDocumentClientCap::LinkSupport, linkSupport);
 REFLECT_STRUCT(TextDocumentClientCap::PublishDiagnostics, relatedInformation);
-REFLECT_STRUCT(TextDocumentClientCap, completion, definition, documentSymbol, publishDiagnostics);
+REFLECT_STRUCT(TextDocumentClientCap, completion, definition, documentSymbol,
+               publishDiagnostics);
 
 struct ClientCap {
   WorkspaceClientCap workspace;
@@ -268,8 +270,9 @@ void *Indexer(void *arg_) {
 
 void Initialize(MessageHandler *m, InitializeParam &param, ReplyOnce &reply) {
   std::string project_path = NormalizePath(param.rootUri->GetPath());
-  LOG_S(INFO) << "initialize in directory " << project_path << " with uri "
-              << param.rootUri->raw_uri;
+  if (auto v = Verbosity::INFO; LogRequire(v))
+    Log(v, "initialize in directory ", project_path, " with uri ",
+        param.rootUri->raw_uri);
 
   {
     g_config = new Config(param.initializationOptions);
@@ -291,7 +294,8 @@ void Initialize(MessageHandler *m, InitializeParam &param, ReplyOnce &reply) {
     rapidjson::Writer<rapidjson::StringBuffer> writer(output);
     JsonWriter json_writer(&writer);
     Reflect(json_writer, *g_config);
-    LOG_S(INFO) << "initializationOptions: " << output.GetString();
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v, "initializationOptions: ", output.GetString());
 
     if (g_config->cache.directory.size()) {
       SmallString<256> Path(g_config->cache.directory);
@@ -320,7 +324,8 @@ void Initialize(MessageHandler *m, InitializeParam &param, ReplyOnce &reply) {
   if (g_config->clang.resourceDir.empty())
     g_config->clang.resourceDir = GetDefaultResourceDirectory();
   DoPathMapping(g_config->clang.resourceDir);
-  LOG_S(INFO) << "use -resource-dir=" << g_config->clang.resourceDir;
+  if (auto v = Verbosity::INFO; LogRequire(v))
+    Log(v, "use -resource-dir=", g_config->clang.resourceDir);
 
   // Send initialization before starting indexers, so we don't send a
   // status update too early.
@@ -352,11 +357,12 @@ void Initialize(MessageHandler *m, InitializeParam &param, ReplyOnce &reply) {
   std::sort(workspaceFolders.begin(), workspaceFolders.end(),
             [](auto &l, auto &r) { return l.first.size() > r.first.size(); });
   for (auto &[folder, real] : workspaceFolders)
-    if (real.empty())
-      LOG_S(INFO) << "workspace folder: " << folder;
-    else
-      LOG_S(INFO) << "workspace folder: " << folder << " -> " << real;
-
+    if (auto v = Verbosity::INFO; LogRequire(v)) {
+      if (real.empty())
+        Log(v, "workspace folder: ", folder);
+      else
+        Log(v, "workspace folder: ", folder, " -> ", real);
+    }
   if (g_config->cache.directory.empty())
     g_config->cache.retainInMemory = 1;
   else if (!g_config->cache.hierarchicalPath)
@@ -378,7 +384,8 @@ void Initialize(MessageHandler *m, InitializeParam &param, ReplyOnce &reply) {
   if (g_config->index.threads == 0)
     g_config->index.threads = std::thread::hardware_concurrency();
 
-  LOG_S(INFO) << "start " << g_config->index.threads << " indexers";
+  if (auto v = Verbosity::INFO; LogRequire(v))
+    Log(v, "start ", g_config->index.threads, " indexers");
   for (int i = 0; i < g_config->index.threads; i++)
     SpawnThread(Indexer, new std::pair<MessageHandler *, int>{m, i});
 
@@ -386,7 +393,8 @@ void Initialize(MessageHandler *m, InitializeParam &param, ReplyOnce &reply) {
   // files, because that takes a long time.
   m->include_complete->Rescan();
 
-  LOG_S(INFO) << "dispatch initial index requests";
+  if (auto v = Verbosity::INFO; LogRequire(v))
+    Log(v, "dispatch initial index requests");
   m->project->Index(m->wfiles, reply.id);
 
   m->manager->sessions.SetCapacity(g_config->session.maxNum);
diff --git a/src/messages/textDocument_completion.cc b/src/messages/textDocument_completion.cc
index cf60847a..19f3960b 100644
--- a/src/messages/textDocument_completion.cc
+++ b/src/messages/textDocument_completion.cc
@@ -31,6 +31,7 @@ limitations under the License.
 namespace ccls {
 using namespace clang;
 using namespace llvm;
+using namespace ccls::log;
 
 REFLECT_UNDERLYING(InsertTextFormat);
 REFLECT_UNDERLYING(CompletionItemKind);
@@ -61,8 +62,7 @@ REFLECT_STRUCT(CompletionList, isIncomplete, items);
 
 #if LLVM_VERSION_MAJOR < 8
 void DecorateIncludePaths(const std::smatch &match,
-                          std::vector<CompletionItem> *items,
-                          char quote) {
+                          std::vector<CompletionItem> *items, char quote) {
   std::string spaces_after_include = " ";
   if (match[3].compare("include") == 0 && quote != '\0')
     spaces_after_include = match[4].str();
@@ -161,12 +161,15 @@ void FilterCandidates(CompletionList &result, const std::string &complete_text,
       auto &edits = item.additionalTextEdits;
       if (overwrite_len > 0) {
         item.textEdit.range.start = overwrite_begin;
-        std::string orig = buffer_line.substr(overwrite_begin.character, overwrite_len);
+        std::string orig =
+            buffer_line.substr(overwrite_begin.character, overwrite_len);
         if (edits.size() && edits[0].range.end == begin_pos &&
             edits[0].range.start.line == begin_pos.line) {
-          int cur_edit_len = edits[0].range.end.character - edits[0].range.start.character;
+          int cur_edit_len =
+              edits[0].range.end.character - edits[0].range.start.character;
           item.textEdit.newText =
-              buffer_line.substr(overwrite_begin.character, overwrite_len - cur_edit_len) +
+              buffer_line.substr(overwrite_begin.character,
+                                 overwrite_len - cur_edit_len) +
               edits[0].newText + item.textEdit.newText;
           edits.erase(edits.begin());
         } else {
@@ -304,7 +307,8 @@ CompletionItemKind GetCompletionKind(CodeCompletionContext::Kind K,
       return CompletionItemKind::Field;
 
     default:
-      LOG_S(WARNING) << "Unhandled " << int(D->getKind());
+      if (auto v = Verbosity::WARNING; LogRequire(v))
+        Log(v, "Unhandled ", int(D->getKind()));
       return CompletionItemKind::Text;
     }
     break;
diff --git a/src/messages/workspace.cc b/src/messages/workspace.cc
index 60ff01ae..785ddaa0 100644
--- a/src/messages/workspace.cc
+++ b/src/messages/workspace.cc
@@ -13,13 +13,13 @@ See the License for the specific language governing permissions and
 limitations under the License.
 ==============================================================================*/
 
-#include "sema_manager.hh"
 #include "fuzzy_match.hh"
 #include "log.hh"
 #include "message_handler.hh"
 #include "pipeline.hh"
 #include "project.hh"
 #include "query.hh"
+#include "sema_manager.hh"
 
 #include <llvm/ADT/STLExtras.h>
 #include <llvm/ADT/StringRef.h>
@@ -30,6 +30,7 @@ limitations under the License.
 #include <functional>
 #include <limits.h>
 using namespace llvm;
+using namespace ccls::log;
 
 namespace ccls {
 REFLECT_STRUCT(SymbolInformation, name, kind, location, containerName);
@@ -81,7 +82,8 @@ void MessageHandler::workspace_didChangeWorkspaceFolders(
   for (const WorkspaceFolder &wf : param.event.removed) {
     std::string root = wf.uri.GetPath();
     EnsureEndsInSlash(root);
-    LOG_S(INFO) << "delete workspace folder " << wf.name << ": " << root;
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v, "delete workspace folder ", wf.name, ": ", root);
     auto it = llvm::find_if(g_config->workspaceFolders,
                             [&](auto &folder) { return folder.first == root; });
     if (it != g_config->workspaceFolders.end()) {
@@ -100,8 +102,9 @@ void MessageHandler::workspace_didChangeWorkspaceFolders(
     std::string real = RealPath(folder) + '/';
     if (folder == real)
       real.clear();
-    LOG_S(INFO) << "add workspace folder " << wf.name << ": "
-                << (real.empty() ? folder : folder + " -> " + real);
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v, "add workspace folder ", wf.name, ": ",
+          (real.empty() ? folder : folder + " -> " + real));
     workspaceFolders.emplace_back();
     auto it = workspaceFolders.end() - 1;
     for (; it != workspaceFolders.begin() && folder < it[-1].first; --it)
diff --git a/src/pipeline.cc b/src/pipeline.cc
index f2b75524..5a5d6611 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -41,6 +41,7 @@ limitations under the License.
 #include <unistd.h>
 #endif
 using namespace llvm;
+using namespace ccls::log;
 namespace chrono = std::chrono;
 
 namespace ccls {
@@ -118,8 +119,9 @@ bool CacheInvalid(VFS *vfs, IndexFile *prev, const std::string &path,
   {
     std::lock_guard<std::mutex> lock(vfs->mutex);
     if (prev->mtime < vfs->state[path].timestamp) {
-      LOG_V(1) << "timestamp changed for " << path
-               << (from ? " (via " + *from + ")" : std::string());
+      if (auto v = Verbosity::DEBUG; LogRequire(v))
+        Log(v, "timestamp changed for ", path,
+            (from ? " (via " + *from + ")" : std::string()));
       return true;
     }
   }
@@ -131,8 +133,9 @@ bool CacheInvalid(VFS *vfs, IndexFile *prev, const std::string &path,
     if (strcmp(prev->args[i], args[i]) && sys::path::stem(args[i]) != stem)
       changed = true;
   if (changed)
-    LOG_V(1) << "args changed for " << path
-             << (from ? " (via " + *from + ")" : std::string());
+    if (auto v = Verbosity::DEBUG; LogRequire(v))
+      Log(v, "args changed for ", path,
+          (from ? " (via " + *from + ")" : std::string()));
   return changed;
 };
 
@@ -215,7 +218,8 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
   }
 
   if (!matcher.Matches(request.path)) {
-    LOG_IF_S(INFO, loud) << "skip " << request.path;
+    if (auto v = Verbosity::INFO; LogIf(v, loud))
+      Log(v, "skip ", request.path);
     return false;
   }
 
@@ -264,21 +268,23 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
       std::unique_lock lock(GetFileMutex(path_to_index));
       prev = RawCacheLoad(path_to_index);
       if (!prev || CacheInvalid(vfs, prev.get(), path_to_index, entry.args,
-          std::nullopt))
+                                std::nullopt))
         break;
       if (track)
         for (const auto &dep : prev->dependencies) {
           if (auto mtime1 = LastWriteTime(dep.first.val().str())) {
             if (dep.second < *mtime1) {
               reparse = 2;
-              LOG_V(1) << "timestamp changed for " << path_to_index << " via "
-                       << dep.first.val().str();
+              if (auto v = Verbosity::DEBUG; LogRequire(v))
+                Log(v, "timestamp changed for ", path_to_index, " via ",
+                    dep.first.val().str());
               break;
             }
           } else {
             reparse = 2;
-            LOG_V(1) << "timestamp changed for " << path_to_index << " via "
-                     << dep.first.val().str();
+            if (auto v = Verbosity::DEBUG; LogRequire(v))
+              Log(v, "timestamp changed for ", path_to_index, " via ",
+                  dep.first.val().str());
             break;
           }
         }
@@ -289,11 +295,12 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
 
       if (vfs->Loaded(path_to_index))
         return true;
-      LOG_S(INFO) << "load cache for " << path_to_index;
+      if (auto v = Verbosity::INFO; LogRequire(v))
+        Log(v, "load cache for ", path_to_index);
       auto dependencies = prev->dependencies;
       IndexUpdate update = IndexUpdate::CreateDelta(nullptr, prev.get());
       on_indexed->PushBack(std::move(update),
-        request.mode != IndexMode::NonInteractive);
+                           request.mode != IndexMode::NonInteractive);
       {
         std::lock_guard lock1(vfs->mutex);
         vfs->state[path_to_index].loaded++;
@@ -318,7 +325,7 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
         }
         IndexUpdate update = IndexUpdate::CreateDelta(nullptr, prev.get());
         on_indexed->PushBack(std::move(update),
-          request.mode != IndexMode::NonInteractive);
+                             request.mode != IndexMode::NonInteractive);
         if (entry.id >= 0) {
           std::lock_guard lock2(project->mtx);
           project->root2folder[entry.root].path2entry_index[path] = entry.id;
@@ -329,12 +336,13 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
 
   if (loud) {
     std::string line;
-    if (LOG_V_ENABLED(1)) {
+    if (LogRequire(Verbosity::DEBUG)) {
       line = "\n ";
       for (auto &arg : entry.args)
         (line += ' ') += arg;
     }
-    LOG_S(INFO) << (deleted ? "delete " : "parse ") << path_to_index << line;
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v, (deleted ? "delete " : "parse "), path_to_index, line);
   }
 
   std::vector<std::unique_ptr<IndexFile>> indexes;
@@ -367,13 +375,13 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
   for (std::unique_ptr<IndexFile> &curr : indexes) {
     std::string path = curr->path;
     if (!matcher.Matches(path)) {
-      LOG_IF_S(INFO, loud) << "skip index for " << path;
+      if (auto v = Verbosity::INFO; LogIf(Verbosity::INFO, loud))
+        Log(v, "skip index for ", path);
       continue;
     }
 
-    if (!deleted)
-      LOG_IF_S(INFO, loud) << "store index for " << path
-                           << " (delta: " << !!prev << ")";
+    if (auto v = Verbosity::INFO; LogIf(v, loud) && !deleted)
+      Log(v, "store index for ", path, " (delta: ", !!prev, ")");
     {
       std::lock_guard lock(GetFileMutex(path));
       int loaded = vfs->Loaded(path), retain = g_config->cache.retainInMemory;
@@ -384,7 +392,7 @@ bool Indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
       if (retain > 0 && retain <= loaded + 1) {
         std::lock_guard lock(g_index_mutex);
         auto it = g_index.insert_or_assign(
-          path, InMemoryIndexFile{curr->file_contents, *curr});
+            path, InMemoryIndexFile{curr->file_contents, *curr});
         std::string().swap(it.first->second.index.file_contents);
       }
       if (g_config->cache.directory.size()) {
@@ -468,8 +476,9 @@ void Indexer_Main(SemaManager *manager, VFS *vfs, Project *project,
 
 void Main_OnIndexed(DB *db, WorkingFiles *wfiles, IndexUpdate *update) {
   if (update->refresh) {
-    LOG_S(INFO)
-        << "loaded project. Refresh semantic highlight for all working file.";
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v,
+          "loaded project. Refresh semantic highlight for all working file.");
     std::lock_guard lock(wfiles->mutex);
     for (auto &[f, wf] : wfiles->files) {
       std::string path = LowerPathIfInsensitive(f);
@@ -545,10 +554,12 @@ void LaunchStdin() {
       std::string method;
       ReflectMember(reader, "id", id);
       ReflectMember(reader, "method", method);
-      if (id.Valid())
-        LOG_V(2) << "receive RequestMessage: " << id.value << " " << method;
-      else
-        LOG_V(2) << "receive NotificationMessage " << method;
+      if (auto v = Verbosity::VERBOSE; LogRequire(v)) {
+        if (id.Valid())
+          Log(v, "receive RequestMessage: ", id.value, " ", method);
+        else
+          Log(v, "receive NotificationMessage ", method);
+      }
       if (method.empty())
         continue;
       received_exit = method == "exit";
@@ -574,7 +585,8 @@ void LaunchStdin() {
                             chrono::steady_clock::now()});
     }
     ThreadLeave();
-  }).detach();
+  })
+      .detach();
 }
 
 void LaunchStdout() {
@@ -592,7 +604,8 @@ void LaunchStdout() {
         break;
     }
     ThreadLeave();
-  }).detach();
+  })
+      .detach();
 }
 
 void MainLoop() {
@@ -702,9 +715,9 @@ void Standalone(const std::string &root) {
   Project project;
   WorkingFiles wfiles;
   VFS vfs;
-  SemaManager manager(
-      nullptr, nullptr, [&](std::string, std::vector<Diagnostic>) {},
-      [](RequestId id) {});
+  SemaManager manager(nullptr, nullptr,
+                      [&](std::string, std::vector<Diagnostic>) {},
+                      [](RequestId id) {});
   IncludeComplete complete(&project);
 
   MessageHandler handler;
@@ -781,7 +794,8 @@ void NotifyOrRequest(const char *method, bool request,
   JsonWriter writer(&w);
   fn(writer);
   w.EndObject();
-  LOG_V(2) << (request ? "RequestMessage: " : "NotificationMessage: ") << method;
+  if (auto v = Verbosity::VERBOSE; LogRequire(v))
+    Log(v, (request ? "RequestMessage: " : "NotificationMessage: "), method);
   for_stdout->PushBack(output.GetString());
 }
 
@@ -809,8 +823,8 @@ static void Reply(RequestId id, const char *key,
   JsonWriter writer(&w);
   fn(writer);
   w.EndObject();
-  if (id.Valid())
-    LOG_V(2) << "respond to RequestMessage: " << id.value;
+  if (auto v = Verbosity::VERBOSE; LogRequire(v) && id.Valid())
+    Log(v, "respond to RequestMessage: ", id.value);
   for_stdout->PushBack(output.GetString());
 }
 
diff --git a/src/project.cc b/src/project.cc
index 25bfa34c..8d61a0a0 100644
--- a/src/project.cc
+++ b/src/project.cc
@@ -37,9 +37,9 @@ limitations under the License.
 #include <rapidjson/writer.h>
 
 #ifdef _WIN32
-# include <Windows.h>
+#include <Windows.h>
 #else
-# include <unistd.h>
+#include <unistd.h>
 #endif
 
 #include <array>
@@ -49,6 +49,7 @@ limitations under the License.
 
 using namespace clang;
 using namespace llvm;
+using namespace ccls::log;
 
 namespace ccls {
 std::pair<LanguageId, bool> lookupExtension(std::string_view filename) {
@@ -91,13 +92,17 @@ struct ProjectProcessor {
         exclude_args.insert(arg);
       else if (Expected<GlobPattern> glob_or_err = GlobPattern::create(arg))
         exclude_globs.push_back(std::move(*glob_or_err));
-      else
-        LOG_S(WARNING) << toString(glob_or_err.takeError());
+      else {
+        if (auto v = Verbosity::WARNING; LogRequire(v))
+          Log(v, toString(glob_or_err.takeError()));
+      }
   }
 
   bool ExcludesArg(StringRef arg) {
+    // clang-format off
     return exclude_args.count(arg) || any_of(exclude_globs,
       [&](const GlobPattern &glob) { return glob.match(arg); });
+    // clang-format on
   }
 
   // Expand %c %cpp ... in .ccls
@@ -172,12 +177,12 @@ struct ProjectProcessor {
     IgnoringDiagConsumer DiagC;
     IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts(new DiagnosticOptions());
     DiagnosticsEngine Diags(
-      IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
-      &DiagC, false);
+        IntrusiveRefCntPtr<DiagnosticIDs>(new DiagnosticIDs()), &*DiagOpts,
+        &DiagC, false);
 
     driver::Driver Driver(args[0], llvm::sys::getDefaultTargetTriple(), Diags);
     auto TargetAndMode =
-      driver::ToolChain::getTargetAndModeFromProgramName(args[0]);
+        driver::ToolChain::getTargetAndModeFromProgramName(args[0]);
     if (!TargetAndMode.TargetPrefix.empty()) {
       const char *arr[] = {"-target", TargetAndMode.TargetPrefix.c_str()};
       args.insert(args.begin() + 1, std::begin(arr), std::end(arr));
@@ -193,7 +198,7 @@ struct ProjectProcessor {
 
     auto CI = std::make_unique<CompilerInvocation>();
     CompilerInvocation::CreateFromArgs(*CI, CCArgs.data(),
-      CCArgs.data() + CCArgs.size(), Diags);
+                                       CCArgs.data() + CCArgs.size(), Diags);
     CI->getFrontendOpts().DisableFree = false;
     CI->getCodeGenOpts().DisableFree = false;
 
@@ -265,25 +270,26 @@ void LoadDirectoryListing(ProjectProcessor &proc, const std::string &root,
     return folder.dot_ccls[root];
   };
 
-  GetFilesInFolder(root, true /*recursive*/, true /*add_folder_to_path*/,
-                   [&folder, &files, &Seen](const std::string &path) {
-                     std::pair<LanguageId, bool> lang = lookupExtension(path);
-                     if (lang.first != LanguageId::Unknown && !lang.second) {
-                       if (!Seen.count(path))
-                         files.push_back(path);
-                     } else if (sys::path::filename(path) == ".ccls") {
-                       std::vector<const char *> args = ReadCompilerArgumentsFromFile(path);
-                       folder.dot_ccls.emplace(sys::path::parent_path(path),
-                                               args);
-                       std::string l;
-                       for (size_t i = 0; i < args.size(); i++) {
-                         if (i)
-                           l += ' ';
-                         l += args[i];
-                       }
-                       LOG_S(INFO) << "use " << path << ": " << l;
-                     }
-                   });
+  GetFilesInFolder(
+      root, true /*recursive*/, true /*add_folder_to_path*/,
+      [&folder, &files, &Seen](const std::string &path) {
+        std::pair<LanguageId, bool> lang = lookupExtension(path);
+        if (lang.first != LanguageId::Unknown && !lang.second) {
+          if (!Seen.count(path))
+            files.push_back(path);
+        } else if (sys::path::filename(path) == ".ccls") {
+          std::vector<const char *> args = ReadCompilerArgumentsFromFile(path);
+          folder.dot_ccls.emplace(sys::path::parent_path(path), args);
+          std::string l;
+          for (size_t i = 0; i < args.size(); i++) {
+            if (i)
+              l += ' ';
+            l += args[i];
+          }
+          if (auto v = Verbosity::INFO; LogRequire(v))
+            Log(v, "use ", path, ": ", l);
+        }
+      });
 
   // If the first line of .ccls is %compile_commands.json, append extra flags.
   for (auto &e : folder.entries)
@@ -367,8 +373,9 @@ void Project::LoadDirectory(const std::string &root, Project::Folder &folder) {
     std::vector<StringRef> args{g_config->compilationDatabaseCommand, root};
     if (sys::ExecuteAndWait(args[0], args, llvm::None, Redir, 0, 0, &err_msg) <
         0) {
-      LOG_S(ERROR) << "failed to execute " << args[0].str() << " "
-                   << args[1].str() << ": " << err_msg;
+      if (auto v = Verbosity::ERROR; LogRequire(v))
+        Log(v, "failed to execute ", args[0].str(), " ", args[1].str(), ": ",
+            err_msg);
       return;
     }
   }
@@ -392,9 +399,11 @@ void Project::LoadDirectory(const std::string &root, Project::Folder &folder) {
   std::vector<Project::Entry> result;
   if (!CDB) {
     if (g_config->compilationDatabaseCommand.size() || sys::fs::exists(Path))
-      LOG_S(ERROR) << "failed to load " << Path.c_str();
+      if (auto v = Verbosity::ERROR; LogRequire(v))
+        Log(v, "failed to load ", Path.c_str());
   } else {
-    LOG_S(INFO) << "loaded " << Path.c_str();
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v, "loaded ", Path.c_str());
     for (tooling::CompileCommand &Cmd : CDB->getAllCompileCommands()) {
       static bool once;
       Project::Entry entry;
@@ -458,7 +467,8 @@ void Project::Load(const std::string &root) {
 
   LoadDirectory(root, folder);
   for (auto &[path, kind] : folder.search_dir2kind)
-    LOG_S(INFO) << "search directory: " << path << ' ' << " \"< "[kind];
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v, "search directory: ", path, ' ', " \"< "[kind]);
 
   // Setup project entries.
   folder.path2entry_index.reserve(folder.entries.size());
@@ -579,8 +589,9 @@ void Project::Index(WorkingFiles *wfiles, RequestId id) {
                                       : IndexMode::NonInteractive,
                           false, id);
         } else {
-          LOG_V(1) << "[" << i << "/" << folder.entries.size() << "]: " << reason
-                   << "; skip " << entry.filename;
+          if (auto v = Verbosity::DEBUG; LogRequire(v))
+            Log(v, "[", i, "/", folder.entries.size(), "]: ", reason, "; skip ",
+                entry.filename);
         }
         i++;
       }
diff --git a/src/sema_manager.cc b/src/sema_manager.cc
index d78b5e06..87a4def1 100644
--- a/src/sema_manager.cc
+++ b/src/sema_manager.cc
@@ -30,6 +30,7 @@ limitations under the License.
 #include <llvm/Support/Threading.h>
 using namespace clang;
 using namespace llvm;
+using namespace ccls::log;
 
 #include <algorithm>
 #include <chrono>
@@ -722,12 +723,13 @@ SemaManager::EnsureSession(const std::string &path, bool *created) {
     session = std::make_shared<ccls::Session>(
         project_->FindEntry(path, false, false), wfiles, PCH);
     std::string line;
-    if (LOG_V_ENABLED(1)) {
+    if (LogRequire(Verbosity::DEBUG)) {
       line = "\n ";
       for (auto &arg : session->file.args)
         (line += ' ') += arg;
     }
-    LOG_S(INFO) << "create session for " << path << line;
+    if (auto v = Verbosity::INFO; LogRequire(v))
+      Log(v, "create session for ", path, line);
     sessions.Insert(path, session);
     if (created)
       *created = true;
@@ -736,7 +738,8 @@ SemaManager::EnsureSession(const std::string &path, bool *created) {
 }
 
 void SemaManager::Clear() {
-  LOG_S(INFO) << "clear all sessions";
+  if (auto v = Verbosity::INFO; LogRequire(v))
+    Log(v, "clear all sessions");
   std::lock_guard lock(mutex);
   sessions.Clear();
 }
diff --git a/src/serializer.cc b/src/serializer.cc
index 0dec4710..3fd2ca59 100644
--- a/src/serializer.cc
+++ b/src/serializer.cc
@@ -30,6 +30,7 @@ limitations under the License.
 #include <stdexcept>
 
 using namespace llvm;
+using namespace ccls::log;
 
 bool gTestOutputMode = false;
 
@@ -426,9 +427,7 @@ CachedHashStringRef InternH(StringRef S) {
   return *R.first;
 }
 
-const char *Intern(StringRef S) {
-  return InternH(S).val().data();
-}
+const char *Intern(StringRef S) { return InternH(S).val().data(); }
 
 std::string Serialize(SerializeFormat format, IndexFile &file) {
   switch (format) {
@@ -485,7 +484,8 @@ Deserialize(SerializeFormat format, const std::string &path,
       file = std::make_unique<IndexFile>(path, file_content);
       ReflectFile(reader, *file);
     } catch (std::invalid_argument &e) {
-      LOG_S(INFO) << "failed to deserialize '" << path << "': " << e.what();
+      if (auto v = Verbosity::INFO; LogRequire(v))
+        Log(v, "failed to deserialize '", path, "': ", e.what());
       return nullptr;
     }
     break;
@@ -510,8 +510,9 @@ Deserialize(SerializeFormat format, const std::string &path,
     try {
       ReflectFile(json_reader, *file);
     } catch (std::invalid_argument &e) {
-      LOG_S(INFO) << "'" << path << "': failed to deserialize "
-                  << json_reader.GetPath() << "." << e.what();
+      if (auto v = Verbosity::INFO; LogRequire(v))
+        Log(v, "'", path, "': failed to deserialize ", json_reader.GetPath(),
+            ".", e.what());
       return nullptr;
     }
     break;
diff --git a/src/utils.cc b/src/utils.cc
index 6ebb4a6e..f57da7f6 100644
--- a/src/utils.cc
+++ b/src/utils.cc
@@ -36,6 +36,7 @@ limitations under the License.
 #include <unordered_map>
 
 using namespace llvm;
+using namespace ccls::log;
 
 namespace ccls {
 struct Matcher::Impl {
@@ -182,7 +183,8 @@ void WriteToFile(const std::string &filename, const std::string &content) {
   FILE *f = fopen(filename.c_str(), "wb");
   if (!f ||
       (content.size() && fwrite(content.c_str(), content.size(), 1, f) != 1)) {
-    LOG_S(ERROR) << "failed to write to " << filename << ' ' << strerror(errno);
+    if (auto v = Verbosity::ERROR; LogRequire(v))
+      Log(v, "failed to write to ", filename, ' ', strerror(errno));
     return;
   }
   fclose(f);
@@ -206,4 +208,4 @@ int ReverseSubseqMatch(std::string_view pat, std::string_view text,
 }
 
 std::string GetDefaultResourceDirectory() { return DEFAULT_RESOURCE_DIRECTORY; }
-}
+} // namespace ccls
diff --git a/src/working_files.cc b/src/working_files.cc
index 6ba8a963..6014e915 100644
--- a/src/working_files.cc
+++ b/src/working_files.cc
@@ -28,6 +28,7 @@ namespace chrono = std::chrono;
 
 using namespace clang;
 using namespace llvm;
+using namespace ccls::log;
 
 namespace ccls {
 namespace {
@@ -329,8 +330,9 @@ std::optional<int> WorkingFile::GetBufferPosFromIndexPos(int line, int *column,
   if (line == (int)index_lines.size() && !*column)
     return buffer_content.size();
   if (line < 0 || line >= (int)index_lines.size()) {
-    LOG_S(WARNING) << "bad index_line (got " << line << ", expected [0, "
-                   << index_lines.size() << ")) in " << filename;
+    if (auto v = Verbosity::WARNING; LogRequire(v))
+      Log(v, "bad index_line (got ", line, ", expected [0, ",
+          index_lines.size(), ")) in ", filename);
     return std::nullopt;
   }
 
@@ -406,7 +408,8 @@ void WorkingFiles::OnChange(const TextDocumentDidChangeParam &change) {
   std::string path = change.textDocument.uri.GetPath();
   WorkingFile *file = GetFileUnlocked(path);
   if (!file) {
-    LOG_S(WARNING) << "Could not change " << path << " because it was not open";
+    if (auto v = Verbosity::WARNING; LogRequire(v))
+      Log(v,"Could not change ", path, " because it was not open");
     return;
   }
 
@@ -482,4 +485,4 @@ std::string_view LexIdentifierAroundPos(Position position,
 
   return content.substr(start, end - start);
 }
-}
+} // namespace ccls