[Truffle] Support --disable-gems.

Author: eregon

core/src/main/java/org/jruby/util/cli/ArgumentProcessor.java

@@ -406,7 +406,6 @@ private void processArgument() {
                         config.setCompileMode(RubyInstanceConfig.CompileMode.TRUFFLE);
                         // Make the static option consistent with the compile mode.
                         Options.COMPILE_MODE.force("TRUFFLE");
-                        config.setDisableGems(true);
                     } else if (extendedOption.endsWith("...")) {
                         Options.listPrefix(extendedOption.substring(0, extendedOption.length() - "...".length()));
                         config.setShouldRunInterpreter(false);

truffle/src/main/java/org/jruby/truffle/language/TruffleBootNodes.java

@@ -158,6 +158,16 @@ public DynamicObject originalLoadPath() {
 
     }
 
+    @CoreMethod(names = "rubygems_enabled?", onSingleton = true)
+    public abstract static class RubygemsEnabledNode extends CoreMethodNode {
+
+        @Specialization
+        public boolean isRubygemsEnabled() {
+            return !getContext().getInstanceConfig().isDisableGems();
+        }
+
+    }
+
     @CoreMethod(names = "source_of_caller", isModuleFunction = true)
     public abstract static class SourceOfCallerNode extends CoreMethodArrayArgumentsNode {
 

truffle/src/main/ruby/post-boot/gems.rb

@@ -11,8 +11,10 @@
 rescue LoadError
 end
 
-begin
-  require 'rubygems'
-rescue LoadError
-  warn('Could not load RubyGems during runtime bootstrap. Please set JRUBY_HOME to an appropriate location.')
-end
+if Truffle::Boot.rubygems_enabled?
+  begin
+    require 'rubygems'
+  rescue LoadError
+    warn('Could not load RubyGems during runtime bootstrap. Please set JRUBY_HOME to an appropriate location.')
+  end
+end

truffle/src/main/ruby/post-boot/shims.rb

@@ -6,9 +6,11 @@
 # GNU General Public License version 2
 # GNU Lesser General Public License version 2.1
 
-module Gem
-  # Update the default_dir to match JRuby's.
-  def self.default_dir
-    File.expand_path(File.join(ConfigMap[:libdir], '..', '..', 'ruby', 'gems', 'shared'))
+if Truffle::Boot.rubygems_enabled?
+  module Gem
+    # Update the default_dir to match JRuby's.
+    def self.default_dir
+      File.expand_path(File.join(ConfigMap[:libdir], '..', '..', 'ruby', 'gems', 'shared'))
+    end
   end
 end