--- a/hotspot/src/share/vm/classfile/systemDictionary.cpp Thu Mar 19 09:13:24 2009 -0700
+++ b/hotspot/src/share/vm/classfile/systemDictionary.cpp Fri Mar 20 23:19:36 2009 -0700
@@ -1964,6 +1964,13 @@
return T_OBJECT;
}
+KlassHandle SystemDictionaryHandles::box_klass(BasicType t) {
+ if (t >= T_BOOLEAN && t <= T_VOID)
+ return KlassHandle(&SystemDictionary::_box_klasses[t], true);
+ else
+ return KlassHandle();
+}
+
// Constraints on class loaders. The details of the algorithm can be
// found in the OOPSLA'98 paper "Dynamic Class Loading in the Java
// Virtual Machine" by Sheng Liang and Gilad Bracha. The basic idea is
@@ -2174,11 +2181,56 @@
}
+// Signature constraints ensure that callers and callees agree about
+// the meaning of type names in their signatures. This routine is the
+// intake for constraints. It collects them from several places:
+//
+// * LinkResolver::resolve_method (if check_access is true) requires
+// that the resolving class (the caller) and the defining class of
+// the resolved method (the callee) agree on each type in the
+// method's signature.
+//
+// * LinkResolver::resolve_interface_method performs exactly the same
+// checks.
+//
+// * LinkResolver::resolve_field requires that the constant pool
+// attempting to link to a field agree with the field's defining
+// class about the type of the field signature.
+//
+// * klassVtable::initialize_vtable requires that, when a class
+// overrides a vtable entry allocated by a superclass, that the
+// overriding method (i.e., the callee) agree with the superclass
+// on each type in the method's signature.
+//
+// * klassItable::initialize_itable requires that, when a class fills
+// in its itables, for each non-abstract method installed in an
+// itable, the method (i.e., the callee) agree with the interface
+// on each type in the method's signature.
+//
+// All those methods have a boolean (check_access, checkconstraints)
+// which turns off the checks. This is used from specialized contexts
+// such as bootstrapping, dumping, and debugging.
+//
+// No direct constraint is placed between the class and its
+// supertypes. Constraints are only placed along linked relations
+// between callers and callees. When a method overrides or implements
+// an abstract method in a supertype (superclass or interface), the
+// constraints are placed as if the supertype were the caller to the
+// overriding method. (This works well, since callers to the
+// supertype have already established agreement between themselves and
+// the supertype.) As a result of all this, a class can disagree with
+// its supertype about the meaning of a type name, as long as that
+// class neither calls a relevant method of the supertype, nor is
+// called (perhaps via an override) from the supertype.
+//
+//
+// SystemDictionary::check_signature_loaders(sig, l1, l2)
+//
// Make sure all class components (including arrays) in the given
// signature will be resolved to the same class in both loaders.
// Returns the name of the type that failed a loader constraint check, or
// NULL if no constraint failed. The returned C string needs cleaning up
-// with a ResourceMark in the caller
+// with a ResourceMark in the caller. No exception except OOME is thrown.
char* SystemDictionary::check_signature_loaders(symbolHandle signature,
Handle loader1, Handle loader2,
bool is_method, TRAPS) {