diff --git a/Rakefile b/Rakefile
index 4422f9688..5d8ba4945 100644
--- a/Rakefile
+++ b/Rakefile
@@ -17,6 +17,11 @@ require "mruby/build"
 MRUBY_CONFIG = MRuby::Build.mruby_config_path
 load MRUBY_CONFIG
 
+# set up all gems
+MRuby.each_target do
+  gems.setup(self) if enable_gems?
+end
+
 # load basic rules
 MRuby.each_target do |build|
   build.define_rules
diff --git a/lib/mruby/gem.rb b/lib/mruby/gem.rb
index 619621e7b..a11c9feda 100644
--- a/lib/mruby/gem.rb
+++ b/lib/mruby/gem.rb
@@ -401,7 +401,16 @@ module MRuby
         end
       end
 
-      def generate_gem_table build
+      def setup(build)
+        gemset = nil
+        begin
+          gemset_prev = gemset
+          self.each(&:setup)
+          gemset = self.setup_dependencies(build).keys.sort
+        end until gemset == gemset_prev
+      end
+
+      def setup_dependencies(build)
         gem_table = each_with_object({}) { |spec, h| h[spec.name] = spec }
 
         default_gems = {}
@@ -424,6 +433,12 @@ module MRuby
           end
         end
 
+        gem_table
+      end
+
+      def generate_gem_table(build)
+        gem_table = setup_dependencies(build)
+
         each do |g|
           g.dependencies.each do |dep|
             name = dep[:gem]
diff --git a/tasks/mrbgems.rake b/tasks/mrbgems.rake
index 272d476e6..291bea615 100644
--- a/tasks/mrbgems.rake
+++ b/tasks/mrbgems.rake
@@ -2,8 +2,6 @@ MRuby.each_target do
   active_gems_txt = "#{build_dir}/mrbgems/active_gems.txt"
 
   if enable_gems?
-    # set up all gems
-    gems.each(&:setup)
     gems.check self
 
     # loader all gems