Xiao Feng, I missed one very important line in gc_heap_slot_write_ref: *p_slot = p_target;
and now I understand why replacing the old call with WB helper you sent in the initial message does not work. I'm going to add store operation into the helper now and retest it. + I'm ok to discuss and clean up GC interface as you proposed after the most simple version of WB is working. On 12/12/06, Xiao-Feng Li <[EMAIL PROTECTED]> wrote:
Mikhail, the gc_heap_slot_write_ref is an old GC interface in ORP. The original idea for this interface is, any Java heap slot reference store should go through this GC function, including VM and Java application. So this function does the real reference store, the original store in JITted code will not be emitted. Hence the OPT write barrier has no problem. The problem with this interface is, it has no clear definition about whether a write barrier is needed or not. That's why I suggested to use a new interface gc_heap_slot_write_barrier for the helper inlining work. The code for it is the same as gc_heap_slot_write_ref for generational GC (without the check for needing barrier or not). Since the WB inlined helper is only invoked when generational GC is run, the check is redundant completely. I am not sure if I make it clear. Thanks, xiaofeng On 12/11/06, Mikhail Fursov <[EMAIL PROTECTED]> wrote: > Xiao-Feng, > I'm slightly confused about current WB support in Jitrino.OPT, so I need an > advice. > > The problem: I think that write barriers in Jitrino OPT do not work. > > Example (see for lines marked with =>): > > > HIR with WB disabled: > > I1:defarg.ths -) t1:cls:java/net/URLClassLoader$4 > I2:tauisnonnull t1 -) t2:tau > I3:tauhastype t1,cls:java/net/URLClassLoader$4 -) t3:tau > I4:defarg -) t4:cls:java/net/URLClassLoader > I5:tauhastype t4,cls:java/net/URLClassLoader -) t5:tau > I6:defarg -) t6:cls:java/lang/String > I7:tauhastype t6,cls:java/lang/String -) t7:tau > I8:ldflda [t1.java/net/URLClassLoader$4::this$0] -) > t8:ref:cls:java/net/URLClassLoader > => I9:stind.unc:o t4 ((t2,t3,t5)) -) [t8] > I10:ldflda [t1.java/net/URLClassLoader$4::val$clsName] -) > t9:ref:cls:java/lang/String > => I11:stind.unc:str t6 ((t2,t3,t7)) -) [t9] > I12:tauunsafe() -) t10:tau > I13:call java/lang/Object::_init_(t1) ((t2,t10)) -) > > > The same HIR with WB enabled: > > Successors: L5 UNWIND > I1:defarg.ths -) t1:cls:java/net/URLClassLoader$4 > I2:tauisnonnull t1 -) t2:tau > I3:tauhastype t1,cls:java/net/URLClassLoader$4 -) t3:tau > I4:defarg -) t4:cls:java/net/URLClassLoader > I5:tauhastype t4,cls:java/net/URLClassLoader -) t5:tau > I6:defarg -) t6:cls:java/lang/String > I7:tauhastype t6,cls:java/lang/String -) t7:tau > I8:ldflda [t1.java/net/URLClassLoader$4::this$0] -) > t8:ref:cls:java/net/URLClassLoader > => I9:stref.wb.unc t4 ((t2,t3,t5)) -) [t8 t1] > I10:ldflda [t1.java/net/URLClassLoader$4::val$clsName] -) > t9:ref:cls:java/lang/String > => I11:stref.wb.unc t6 ((t2,t3,t7)) -) [t9 t1] > I12:tauunsafe() -) t10:tau > I13:call java/lang/Object::_init_(t1) ((t2,t10)) -) > > > > The LIR with WB disabled > > I1: t4:ref:cls:java/net/URLClassLoader (ID:s5(EFLGS):uint32) =ADD > t0:cls:java/net/URLClassLoader$4,t3(0:fo:java/net/URLClassLoader$4.this$0):intptr > > => I2: (AD:t6[t4]:object) =CopyPseudoInst/MOV > (AU:t1:cls:java/net/URLClassLoader) > I3: t8:ref:cls:java/lang/String (ID:s5(EFLGS):uint32) =ADD > t0:cls:java/net/URLClassLoader$4,t7(0:fo:java/net/URLClassLoader$4.val$clsName):intptr > > => I4: (AD:t9[t8]:string) =CopyPseudoInst/MOV > (AU:t2:cls:java/lang/String) > > > > > The same LIR with WB enabled > > I1: t4:ref:cls:java/net/URLClassLoader (ID:s5(EFLGS):uint32) =ADD > t0:cls:java/net/URLClassLoader$4,t3(0:fo:java/net/URLClassLoader$4.this$0):intptr > > => I2: CALL t6(0:h:WriteBarrier):ptr:intptr > (AU:t0:cls:java/net/URLClassLoader$4,t4:ref:cls:java/net/URLClassLoader,t1:cls:java/net/URLClassLoader) > > I3: t8:ref:cls:java/lang/String (ID:s5(EFLGS):uint32) =ADD > t0:cls:java/net/URLClassLoader$4,t7(0:fo:java/net/URLClassLoader$4.val$clsName):intptr > > => I4: CALL t9(0:h:WriteBarrier):ptr:intptr > (AU:t0:cls:java/net/URLClassLoader$4,t8:ref:cls:java/lang/String,t2:cls:java/lang/String) > > > > The question is what is in the CALL? I see only the method: > gc_heap_slot_write_ref and this method does not save anything into fields. > Does it mean that WB support in Jitrino.OPT is incomplete today? > > -- > Mikhail Fursov > >
-- Mikhail Fursov
