diff --git a/src/pipeline.cc b/src/pipeline.cc
index ee3055a1..02b0490c 100644
--- a/src/pipeline.cc
+++ b/src/pipeline.cc
@@ -378,11 +378,8 @@ bool indexer_Parse(SemaManager *completion, WorkingFiles *wfiles,
     (Twine(deleted ? "delete " : "parse ") + path_to_index).toVector(msg);
     if (n_errs)
       msg += " error:" + std::to_string(n_errs) + ' ' + first_error;
-    if (LOG_V_ENABLED(1)) {
-      msg += "\n ";
-      for (const char *arg : entry.args)
-        (msg += ' ') += arg;
-    }
+    if (LOG_V_ENABLED(1))
+      msg += "\n  " + escapeArgs(entry.args);
     LOG_S(INFO) << std::string_view(msg.data(), msg.size());
   }
 
diff --git a/src/project.cc b/src/project.cc
index 6910a4be..e9eb3faa 100644
--- a/src/project.cc
+++ b/src/project.cc
@@ -59,6 +59,20 @@ std::pair<LanguageId, bool> lookupExtension(std::string_view filename) {
   return {ret, header};
 }
 
+std::string escapeArgs(const std::vector<const char *> &args) {
+  std::string ret;
+  for (const char *arg_c : args) {
+    if (ret.size())
+      ret += ' ';
+    std::string_view arg(arg_c);
+    if (arg.find_first_of("\"()<>") != std::string::npos)
+      ((ret += "'") += arg) += "'";
+    else
+      ret += arg;
+  }
+  return ret;
+}
+
 namespace {
 
 enum OptionClass {
diff --git a/src/project.hh b/src/project.hh
index d7bf12c7..2eace444 100644
--- a/src/project.hh
+++ b/src/project.hh
@@ -16,6 +16,7 @@ namespace ccls {
 struct WorkingFiles;
 
 std::pair<LanguageId, bool> lookupExtension(std::string_view filename);
+std::string escapeArgs(const std::vector<const char *> &args);
 
 struct Project {
   struct Entry {
diff --git a/src/sema_manager.cc b/src/sema_manager.cc
index bf806e47..a36f9504 100644
--- a/src/sema_manager.cc
+++ b/src/sema_manager.cc
@@ -768,11 +768,8 @@ 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)) {
-      line = "\n ";
-      for (auto &arg : session->file.args)
-        (line += ' ') += arg;
-    }
+    if (LOG_V_ENABLED(1))
+      line = "\n  " + escapeArgs(session->file.args);
     LOG_S(INFO) << "create session for " << path << line;
     sessions.insert(path, session);
     if (created)