7009266: G1: assert(obj->is_oop_or_null(true )) failed: Error

A referent object that is only weakly reachable at the start of concurrent marking but is re-attached to the strongly reachable object graph during marking may not be marked as live. This can cause the reference object to be processed prematurely and leave dangling pointers to the referent object. Implement a read barrier for the java.lang.ref.Reference::referent field by intrinsifying the Reference.get() method, and intercepting accesses though JNI, reflection, and Unsafe, so that when a non-null referent object is read it is also logged in an SATB buffer.

Reviewed-by: kvn, iveresov, never, tonyp, dholmes
This commit is contained in:
John Cuthbertson 2011-04-07 09:53:20 -07:00
parent aac4647e6e
commit a08e1ce906
41 changed files with 1423 additions and 268 deletions

View file

@ -936,6 +936,26 @@ address InterpreterGenerator::generate_accessor_entry(void) {
}
address InterpreterGenerator::generate_Reference_get_entry(void) {
#ifndef SERIALGC
if (UseG1GC) {
// We need to generate have a routine that generates code to:
// * load the value in the referent field
// * passes that value to the pre-barrier.
//
// In the case of G1 this will record the value of the
// referent in an SATB buffer if marking is active.
// This will cause concurrent marking to mark the referent
// field as live.
Unimplemented();
}
#endif // SERIALGC
// If G1 is not enabled then attempt to go through the accessor entry point
// Reference.get is an accessor
return generate_accessor_entry();
}
//
// C++ Interpreter stub for calling a native method.
// This sets up a somewhat different looking stack for calling the native method
@ -2210,6 +2230,8 @@ address AbstractInterpreterGenerator::generate_method_entry(AbstractInterpreter:
case Interpreter::java_lang_math_log : // fall thru
case Interpreter::java_lang_math_log10 : // fall thru
case Interpreter::java_lang_math_sqrt : entry_point = ((InterpreterGenerator*)this)->generate_math_entry(kind); break;
case Interpreter::java_lang_ref_reference_get
: entry_point = ((InterpreterGenerator*)this)->generate_Reference_get_entry(); break;
default : ShouldNotReachHere(); break;
}