patch for 0.12 (was: Re: java.lang.System changes)

[Steven Augart]

Jeroen Frijters wrote:
> Steven Augart wrote:
>
> > I received a suggestion in private mail from David Holmes (who's been
> > generous with his time in discussing this with me) that we could
> > break up the initialization of java.lang.System into two
> > explicitly-invoked phases, and that a VM could optionally 
> > request that the initialization be broken up, based on a
> > configuration setting.
> > I've asked him for permission to forward the full text of his 
> > suggestion to the list.
> > I think that is the approach we will have to take.
>
>
> Isn't it about time that we consider my suggestion to radically reduce
> the whole initialization ordering mess by moving everything into
> separate classes in the gnu.classpath.internal package?

I haven't read over your suggestion yet (I haven't been following the
classpath list as closely as I should have for the past month or so),
but it does sound like a good idea.  Obviously, with a release coming
out today, a temporary patch is probably a better idea, if it can be
squeezed in.

And, to that end, I have the following small patch that makes
the current Classpath CVS head work with Jikes RVM.  If someone
else approves it, I'll commit it.
--
Steven Augart

Jikes RVM, a free, open source, Virtual Machine:
http://oss.software.ibm.com/jikesrvm

This patch should be committed with the following ChangeLog entry:

2004-11-12  Steven Augart  <address@hidden>

        * gnu/classpath/Configuration.java.in: Added
        JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION. 
        * configure.ac: Added
        --enable-java-lang-system-explicit-initialization. 
        * java/lang/System.java: Added support for
        JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION. 
        
        
Index: configure.ac
===================================================================
RCS file: /cvsroot/classpath/classpath/configure.ac,v
retrieving revision 1.55
diff -I*.class -u -r1.55 configure.ac
--- configure.ac        26 Oct 2004 20:26:03 -0000      1.55
+++ configure.ac        12 Nov 2004 16:10:43 -0000
@@ -287,6 +287,23 @@
               [INIT_LOAD_LIBRARY="true"])
 AC_SUBST(INIT_LOAD_LIBRARY)
 
+
+dnl -----------------------------------------------------------
+dnl Should the VM explicitly run class initialization subfunctions for
+dnl java.lang.System?   (default is false -- the subfunctions will be run 
+dnl automatically by the class initializer)
+dnl -----------------------------------------------------------
+AC_ARG_ENABLE([java-lang-system-explicit-initialization],
+              
[AS_HELP_STRING(--enable-java-lang-system-explicit-initialization,will the VM 
explicitly invoke java.lang.System's static initialization methods 
[default=no])],
+              [case "${enableval}" in 
+                yes|true) JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION="true" ;;
+                no|false) JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION="false" ;;
+                *) AC_MSG_ERROR(bad value ${enableval} for 
--enable-java-lang-system-explicit-initialization) ;;
+              esac],
+              [JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION="false"])
+AC_SUBST(JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION)
+
+
 dnl -----------------------------------------------------------
 dnl avoiding automake complaints
 dnl -----------------------------------------------------------
Index: java/lang/System.java
===================================================================
RCS file: /cvsroot/classpath/classpath/java/lang/System.java,v
retrieving revision 1.43
diff -I*.class -u -r1.43 System.java
--- java/lang/System.java       8 Nov 2004 08:54:50 -0000       1.43
+++ java/lang/System.java       12 Nov 2004 16:10:43 -0000
@@ -64,8 +64,11 @@
    * The System Class Loader (a.k.a. Application Class Loader). The one
    * returned by ClassLoader.getSystemClassLoader. It lives here to prevent
    * a circular initialization dependency between System and ClassLoader.
+   *
+   * We can't make it a blank final, since initSystemClassLoader is a
+   * sub-function.
    */
-  static final ClassLoader systemClassLoader;
+  static ClassLoader systemClassLoader;
 
   /**
    * Stores the current system properties. This can be modified by
@@ -119,12 +122,32 @@
    */
   static
   {
+    if (! Configuration.JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION) {
+      initLoadLibrary();
+      initProperties();
+    }
+    // We *have to* explicitly initialize the streams here, since they're a
+    // blank final field.
+    in = VMSystem.makeStandardInputStream();
+    out = VMSystem.makeStandardOutputStream();
+    err = VMSystem.makeStandardErrorStream();
+    
+    if (! Configuration.JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION) {
+      initSystemClassLoader();
+      initSecurityManager();    // Includes getting the class loader.
+    }
+  }
+
+  static void initLoadLibrary () {
     // Note that this loadLibrary() takes precedence over the one in Object,
     // since Object.<clinit> is waiting for System.<clinit> to complete
     // first; but loading a library twice is harmless.
     if (Configuration.INIT_LOAD_LIBRARY)
       loadLibrary("javalang");
 
+  }
+
+  static void initProperties() {
     Properties defaultProperties = Runtime.defaultProperties;
     defaultProperties.put("gnu.classpath.home",
                    Configuration.CLASSPATH_HOME);
@@ -286,13 +309,13 @@
     // Note that we use clone here and not new.  Some programs assume
     // that the system properties do not have a parent.
     properties = (Properties) Runtime.defaultProperties.clone();
+  }
 
-    in = VMSystem.makeStandardInputStream();
-    out = VMSystem.makeStandardOutputStream();
-    err = VMSystem.makeStandardErrorStream();
-
+  static void initSystemClassLoader() {
     systemClassLoader = VMClassLoader.getSystemClassLoader();
+  }
 
+  static void initSecurityManager () {
     String secman = properties.getProperty("java.security.manager");
     if (secman != null)
       {
Index: gnu/classpath/Configuration.java.in
===================================================================
RCS file: /cvsroot/classpath/classpath/gnu/classpath/Configuration.java.in,v
retrieving revision 1.12
diff -I*.class -u -r1.12 Configuration.java.in
--- gnu/classpath/Configuration.java.in 17 Nov 2003 18:56:51 -0000      1.12
+++ gnu/classpath/Configuration.java.in 12 Nov 2004 16:10:43 -0000
@@ -1,3 +1,4 @@
+/* -*-java-*- */
 /* gnu.classpath.Configuration
    Copyright (C) 1998, 2001, 2003 Free Software Foundation, Inc.
 
@@ -110,4 +111,16 @@
    * Name of default AWT peer library.
    */
   String default_awt_peer_toolkit = "gnu.java.awt.peer.gtk.GtkToolkit";
+
+  /**
+   * Whether to automatically run the init* methods in java.lang.System
+   * (the default) at class initialization time or whether to have the VM
+   * explicitly invoke them.
+   *
+   * The default is false, meaning the VM does not explicitly run the
+   * initializers. 
+   * 
+   */
+  boolean JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION = 
+         @JAVA_LANG_SYSTEM_EXPLICIT_INITIALIZATION@;
 }