natClassLoader.cc (_Jv_RegisterInitiatingLoader): Check loading constraints.

	* java/lang/natClassLoader.cc (_Jv_RegisterInitiatingLoader):
	Check loading constraints.
	(_Jv_CheckOrCreateLoadingConstraint): New function.
	* java/lang/ClassLoader.java (loadingConstraints): New field.
	* link.cc (_Jv_Linker::find_field): Use
	_Jv_CheckOrCreateLoadingConstraint.
	(_Jv_Linker::check_loading_constraints): New function.
	(_Jv_Linker::resolve_method_entry): Use
	check_loading_constraints.
	(_Jv_Linker::append_partial_itable): Likewise.
	(_Jv_Linker::layout_vtable_methods): Likewise.
	* include/jvm.h (_Jv_Linker::check_loading_constraints): Declare.
	(_Jv_CheckOrCreateLoadingConstraint): Declare.

From-SVN: r133172

1 files changed, 57 insertions, 2 deletions

diff --git a/libjava/java/lang/natClassLoader.cc b/libjava/java/lang/natClassLoader.cc
index 9a687ff..fac1e4d 100644
--- a/libjava/java/lang/natClassLoader.cc
+++ b/libjava/java/lang/natClassLoader.cc
@@ -1,6 +1,6 @@
 // natClassLoader.cc - Implementation of java.lang.ClassLoader native methods.
 
-/* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006  Free Software Foundation
+/* Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2008  Free Software Foundation
 
    This file is part of libgcj.
 
@@ -41,6 +41,7 @@ details.  */
 #include <java/lang/StringBuffer.h>
 #include <java/io/Serializable.h>
 #include <java/lang/Cloneable.h>
+#include <java/lang/ref/WeakReference.h>
 #include <java/util/HashMap.h>
 #include <gnu/gcj/runtime/BootClassLoader.h>
 #include <gnu/gcj/runtime/SystemClassLoader.h>
@@ -143,7 +144,21 @@ _Jv_RegisterInitiatingLoader (jclass klass, java::lang::ClassLoader *loader)
       // them later.
       return;
     }
-  loader->loadedClasses->put(klass->name->toString(), klass);
+
+  JvSynchronize sync (loader->loadingConstraints);
+
+  using namespace java::lang::ref;
+
+  jstring name = klass->getName();
+  WeakReference *ref = (WeakReference *) loader->loadingConstraints->get (name);
+  if (ref)
+    {
+      jclass constraint = (jclass) ref->get();
+      if (constraint && constraint != klass)
+	throw new java::lang::LinkageError(JvNewStringLatin1("loading constraint violated"));
+    }
+  loader->loadingConstraints->put(name, new WeakReference(klass));
+  loader->loadedClasses->put(name, klass);
 }
 
 // If we found an error while defining an interpreted class, we must
@@ -156,6 +171,46 @@ _Jv_UnregisterInitiatingLoader (jclass klass, java::lang::ClassLoader *loader)
   loader->loadedClasses->remove(klass->name->toString());
 }
 
+// Check a loading constraint.  In particular check that, if there is
+// a constraint for the name of KLASS in LOADER, that it maps to
+// KLASS.  If there is no such constraint, make a new one.  If the
+// constraint is violated, throw an exception.  Do nothing for
+// primitive types.
+void
+_Jv_CheckOrCreateLoadingConstraint (jclass klass,
+				    java::lang::ClassLoader *loader)
+{
+  // Strip arrays.
+  while (klass->isArray())
+    klass = klass->getComponentType();
+  // Ignore primitive types.
+  if (klass->isPrimitive())
+    return;
+
+  if (! loader)
+    loader = java::lang::VMClassLoader::bootLoader;
+  jstring name = klass->getName();
+
+  JvSynchronize sync (loader->loadingConstraints);
+
+  using namespace java::lang::ref;
+
+  WeakReference *ref = (WeakReference *) loader->loadingConstraints->get (name);
+  if (ref)
+    {
+      jclass constraint = (jclass) ref->get();
+      if (constraint)
+	{
+	  if (klass != constraint)
+	    throw new java::lang::LinkageError(JvNewStringLatin1("loading constraint violated"));
+	  // Otherwise, all is ok.
+	  return;
+	}
+    }
+  // No constraint (or old constraint GC'd).  Make a new one.
+  loader->loadingConstraints->put(name, new WeakReference(klass));
+}
+
 
 // Class registration.
 //