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8222005: ClassRedefinition crashes with: guarantee(false) failed: OLD and/or OBSOLETE method(s) found

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Remove optimizations from class redefinition that cause the guarantee hit

Reviewed-by: coleenp, dcubed
This commit is contained in:
Serguei Spitsyn 2020-06-11 05:53:33 +00:00
parent bb5e5b3826
commit 2ff9f53a44
3 changed files with 63 additions and 65 deletions
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58
src/hotspot/share/prims/jvmtiRedefineClasses.cpp
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@ -70,8 +70,9 @@ Method** VM_RedefineClasses::_added_methods = NULL;
int VM_RedefineClasses::_matching_methods_length = 0;
int VM_RedefineClasses::_deleted_methods_length = 0;
int VM_RedefineClasses::_added_methods_length = 0;
// This flag is global as the constructor does not reset it:
bool VM_RedefineClasses::_has_redefined_Object = false;
bool VM_RedefineClasses::_has_null_class_loader = false;
u8 VM_RedefineClasses::_id_counter = 0;
VM_RedefineClasses::VM_RedefineClasses(jint class_count,
@ -83,8 +84,6 @@ VM_RedefineClasses::VM_RedefineClasses(jint class_count,
_any_class_has_resolved_methods = false;
_res = JVMTI_ERROR_NONE;
_the_class = NULL;
_has_redefined_Object = false;
_has_null_class_loader = false;
_id = next_id();
}
@ -3598,7 +3597,10 @@ void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
bool trace_name_printed = false;
// If the class being redefined is java.lang.Object, we need to fix all
// array class vtables also
// array class vtables also. The _has_redefined_Object flag is global.
// Once the java.lang.Object has been redefined (by the current or one
// of the previous VM_RedefineClasses operations) we have to always
// adjust method entries for array classes.
if (k->is_array_klass() && _has_redefined_Object) {
k->vtable().adjust_method_entries(&trace_name_printed);
@ -3616,22 +3618,6 @@ void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
}
}
// HotSpot specific optimization! HotSpot does not currently
// support delegation from the bootstrap class loader to a
// user-defined class loader. This means that if the bootstrap
// class loader is the initiating class loader, then it will also
// be the defining class loader. This also means that classes
// loaded by the bootstrap class loader cannot refer to classes
// loaded by a user-defined class loader. Note: a user-defined
// class loader can delegate to the bootstrap class loader.
//
// If the current class being redefined has a user-defined class
// loader as its defining class loader, then we can skip all
// classes loaded by the bootstrap class loader.
if (!_has_null_class_loader && ik->class_loader() == NULL) {
return;
}
// Adjust all vtables, default methods and itables, to clean out old methods.
ResourceMark rm(_thread);
if (ik->vtable_length() > 0) {
@ -3650,21 +3636,24 @@ void VM_RedefineClasses::AdjustAndCleanMetadata::do_klass(Klass* k) {
// constant pool cache holds the Method*s for non-virtual
// methods and for virtual, final methods.
//
// Special case: if the current class being redefined, then new_cp
// has already been attached to the_class and old_cp has already
// been added as a previous version. The new_cp doesn't have any
// cached references to old methods so it doesn't need to be
// updated. We can simply start with the previous version(s) in
// that case.
// Special case: if the current class is being redefined by the current
// VM_RedefineClasses operation, then new_cp has already been attached
// to the_class and old_cp has already been added as a previous version.
// The new_cp doesn't have any cached references to old methods so it
// doesn't need to be updated and we could optimize by skipping it.
// However, the current class can be marked as being redefined by another
// VM_RedefineClasses operation which has already executed its doit_prologue
// and needs cpcache method entries adjusted. For simplicity, the cpcache
// update is done unconditionally. It should result in doing nothing for
// classes being redefined by the current VM_RedefineClasses operation.
// Method entries in the previous version(s) are adjusted as well.
ConstantPoolCache* cp_cache;
if (!ik->is_being_redefined()) {
// this klass' constant pool cache may need adjustment
ConstantPool* other_cp = ik->constants();
cp_cache = other_cp->cache();
if (cp_cache != NULL) {
cp_cache->adjust_method_entries(&trace_name_printed);
}
// this klass' constant pool cache may need adjustment
ConstantPool* other_cp = ik->constants();
cp_cache = other_cp->cache();
if (cp_cache != NULL) {
cp_cache->adjust_method_entries(&trace_name_printed);
}
// the previous versions' constant pool caches may need adjustment
@ -4109,9 +4098,8 @@ void VM_RedefineClasses::redefine_single_class(jclass the_jclass,
InstanceKlass* the_class = get_ik(the_jclass);
// Set some flags to control and optimize adjusting method entries
// Set a flag to control and optimize adjusting method entries
_has_redefined_Object |= the_class == SystemDictionary::Object_klass();
_has_null_class_loader |= the_class->class_loader() == NULL;
// Remove all breakpoints in methods of this class
JvmtiBreakpoints& jvmti_breakpoints = JvmtiCurrentBreakpoints::get_jvmti_breakpoints();