Refactor

elf/cmdline.cc

@@ -1407,6 +1407,13 @@ std::vector<std::string> parse_nonpositional_args(Context<E> &ctx) {
       ctx.arg.dependency_file = ctx.arg.chroot + "/" + ctx.arg.dependency_file;
   }
 
+  // Mark GC root symbols
+  for (Symbol<E> *sym : ctx.arg.undefined)
+    sym->gc_root = true;
+  for (Symbol<E> *sym : ctx.arg.require_defined)
+    sym->gc_root = true;
+  ctx.arg.entry->gc_root = true;
+
   if (version_shown && remaining.empty())
     exit(0);
   return remaining;

elf/gc-sections.cc

@@ -110,28 +110,13 @@ static void collect_root_set(Context<E> &ctx,
     }
   });
 
-  // Add sections containing exported symbols
+  // Add sections containing gc root or exported symbols
   tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
     for (Symbol<E> *sym : file->symbols)
-      if (sym->file == file && sym->is_exported)
+      if (sym->file == file && (sym->gc_root || sym->is_exported))
         enqueue_symbol(sym);
   });
 
-  // Add sections referenced by root symbols.
-  for (Symbol<E> *sym : ctx.arg.undefined)
-    enqueue_symbol(sym);
-
-  for (Symbol<E> *sym : ctx.arg.require_defined)
-    enqueue_symbol(sym);
-
-  if (!ctx.arg.undefined_glob.empty()) {
-    tbb::parallel_for_each(ctx.objs, [&](ObjectFile<E> *file) {
-      for (Symbol<E> *sym : file->get_global_syms())
-        if (sym->file == file && ctx.arg.undefined_glob.find(sym->name()))
-          enqueue_symbol(sym);
-    });
-  }
-
   // .eh_frame consists of variable-length records called CIE and FDE
   // records, and they are a unit of inclusion or exclusion.
   // We just keep all CIEs and everything that are referenced by them.

elf/mold.h

@@ -2225,6 +2225,9 @@ class Symbol {
   bool has_copyrel : 1 = false;
   bool is_copyrel_readonly : 1 = false;
 
+  // For --gc-sections
+  bool gc_root : 1 = false;
+
   // For LTO. True if the symbol is referenced by a regular object (as
   // opposed to IR object).
   bool referenced_by_regular_obj : 1 = false;

elf/passes.cc

@@ -205,6 +205,7 @@ static void mark_live_objects(Context<E> &ctx) {
         for (Symbol<E> *sym : file->get_global_syms()) {
           if (sym->file == file && ctx.arg.undefined_glob.find(sym->name())) {
             file->is_alive = true;
+            sym->gc_root = true;
             break;
           }
         }