Request for review(S): 6991512: G1 barriers fail with 64bit C1

[Tom Rodriguez]

On Oct 12, 2010, at 5:12 PM, Igor Veresov wrote:

> This fixes two problems:
> 1. On x64, c1_LIR.hpp:401,
> # assert(is_single_cpu() && !is_virtual()) failed: type check
> 
> Which is due to passing a pointer to T_LONG instead of T_OBJECT to G1 post-barrier when emitting LIR for CompareAndSwap intrinsic. The fix is to create a register with an appropriate type when CASing an object reference.

Looks good.

> 
> 2. On sparc, assembler_sparc.hpp:843,
> # assert(nbits == 32 || -(1 << nbits-1) <= x && x < ( 1 << nbits-1)) failed: value out of range
> 
> This one is due to the limited jump range of branch-on-reg-value instruction. The solution is to use cmp+brx since the jump target is not guaranteed to be in 16 bit range (the target is a continuation of a stub).

In this particular case the label should be bound when emit_code is called so you could in fact check the distance and use br_on_reg_cond if it will reach.  It seems like it mostly reaches.  Using the longer sequence is fine too.

tom

> 
> 
> Webrev: http://cr.openjdk.java.net/~iveresov/6991512/webrev.00/
> 
> 
> Tested with a couple of failed nightlies.
> 
> Thanks,
> igor
>