Small VM change #2: JVM_ entry point to extend the boot class path

[Mark Reinhold]

> Date: Mon, 18 May 2009 16:47:53 -0400
> From: karen.kinnear at sun.com

> Let's consider this a temporary J1 approach please. After J1 let's
> have some discussions about alternative approaches please.

Sure, absolutely.

> Question: in jvm.cpp and .hpp in the new
> JVM_ExtendBootClassPath(JNIEnv *env, jclass cls, const char *path)
> what is jclass cls used for?

Nothing; that's leftover from an initial version where I thought I was
going to use RegisterNatives for this entry point.  Removed.

> also in that method, I suspect you too would like the
> ClassLoader::print_bootclasspath() to be conditional on
> TraceClassLoading - unless for the demo you want this to print always.

I meant to remove that entirely, but gating it on TraceClassLoading makes
sense, so I'll do that.

> Other than that - just for the demo - go for it.

Thanks.  New patch attached FYI.

- Mark

-------------- next part --------------
diff -r 403a1b93874f make/linux/makefiles/mapfile-vers-debug
--- a/make/linux/makefiles/mapfile-vers-debug	Thu May 14 14:48:35 2009 -0700
+++ b/make/linux/makefiles/mapfile-vers-debug	Mon May 18 15:32:49 2009 -0700
@@ -87,6 +87,7 @@
                 JVM_DumpThreads;
                 JVM_EnableCompiler;
                 JVM_Exit;
+                JVM_ExtendBootClassPath;
                 JVM_FillInStackTrace;
                 JVM_FindClassFromClass;
                 JVM_FindClassFromClassLoader;
diff -r 403a1b93874f make/linux/makefiles/mapfile-vers-product
--- a/make/linux/makefiles/mapfile-vers-product	Thu May 14 14:48:35 2009 -0700
+++ b/make/linux/makefiles/mapfile-vers-product	Mon May 18 15:32:49 2009 -0700
@@ -87,6 +87,7 @@
                 JVM_DumpThreads;
                 JVM_EnableCompiler;
                 JVM_Exit;
+                JVM_ExtendBootClassPath;
                 JVM_FillInStackTrace;
                 JVM_FindClassFromClass;
                 JVM_FindClassFromClassLoader;
diff -r 403a1b93874f src/share/vm/classfile/classLoader.cpp
--- a/src/share/vm/classfile/classLoader.cpp	Thu May 14 14:48:35 2009 -0700
+++ b/src/share/vm/classfile/classLoader.cpp	Mon May 18 15:32:49 2009 -0700
@@ -512,12 +512,15 @@
     // File or directory found
     ClassPathEntry* new_entry = NULL;
     create_class_path_entry((char *)path, st, &new_entry, LazyBootClassLoader);
-    // The kernel VM adds dynamically to the end of the classloader path and
-    // doesn't reorder the bootclasspath which would break java.lang.Package
-    // (see PackageInfo).
-    // Add new entry to linked list
+    // The kernel VM, and Jigsaw, add dynamically to the end of the classloader
+    // path and don't reorder the bootclasspath, which would break
+    // java.lang.Package (see PackageInfo).
     if (!check_for_duplicates || !contains_entry(new_entry)) {
+      // Add new entry to linked list
       add_to_list(new_entry);
+      if (TraceClassLoading) {
+        print_bootclasspath();
+      }
     }
   }
 }
diff -r 403a1b93874f src/share/vm/classfile/classLoader.hpp
--- a/src/share/vm/classfile/classLoader.hpp	Thu May 14 14:48:35 2009 -0700
+++ b/src/share/vm/classfile/classLoader.hpp	Mon May 18 15:32:49 2009 -0700
@@ -190,7 +190,7 @@
   // to avoid confusing the zip library
   static bool get_canonical_path(char* orig, char* out, int len);
  public:
-  // Used by the kernel jvm.
+  // Used by the kernel jvm, and by Jigsaw via JVM_ExtendBootClassPath
   static void update_class_path_entry_list(const char *path,
                                            bool check_for_duplicates);
   static void print_bootclasspath();
diff -r 403a1b93874f src/share/vm/prims/jvm.cpp
--- a/src/share/vm/prims/jvm.cpp	Thu May 14 14:48:35 2009 -0700
+++ b/src/share/vm/prims/jvm.cpp	Mon May 18 15:32:49 2009 -0700
@@ -851,6 +851,17 @@
             (jclass) JNIHandles::make_local(env, Klass::cast(k)->java_mirror());
 JVM_END
 
+JVM_ENTRY(void, JVM_ExtendBootClassPath(JNIEnv *env, const char *path))
+  JVMWrapper2("JVM_ExtendBootClassPath(%s)", path)
+  {
+    // cf. SystemDictionary::download_and_retry_class_load
+    HandleMark hm(THREAD);
+    ResourceMark rm(THREAD);
+    Handle loader_lock(THREAD, SystemDictionary::system_loader_lock());
+    ObjectLocker ol(loader_lock, THREAD);
+    ClassLoader::update_class_path_entry_list(path, true);
+  }
+JVM_END
 
 // Reflection support //////////////////////////////////////////////////////////////////////////////
 
diff -r 403a1b93874f src/share/vm/prims/jvm.h
--- a/src/share/vm/prims/jvm.h	Thu May 14 14:48:35 2009 -0700
+++ b/src/share/vm/prims/jvm.h	Mon May 18 15:32:49 2009 -0700
@@ -438,6 +438,12 @@
                       jobjectArray constants);
 
 /*
+ * Append a path to the boot class path
+ */
+JNIEXPORT void JNICALL
+JVM_ExtendBootClassPath(JNIEnv *env, const char *path);
+
+/*
  * Reflection support functions
  */