RFR(XS): 8234645: ARM32: C1: PatchingStub for field access: not enough bytes

[Lindenmaier, Goetz]

Hi Martin, 

the change looks good. 
I had to take a second look to grok your comment. Mentioning "2nd"
is a bit shaky.
I would prefer if you either move up the real comment to the 
first occurrence in the function, and add comment "// see above" at 
the others.  

Or you say:
// see comment before patching_epilog for 2nd ldr (str respectively)

Don't need a webrev for this.

Best regards,
  Goetz.


> -----Original Message-----
> From: hotspot-compiler-dev <hotspot-compiler-dev-
> bounces at openjdk.java.net> On Behalf Of Doerr, Martin
> Sent: Dienstag, 26. November 2019 17:22
> To: christoph.goettschkes at microdoc.com; 'hotspot-compiler-
> dev at openjdk.java.net' <hotspot-compiler-dev at openjdk.java.net>
> Subject: [CAUTION] RFR(XS): 8234645: ARM32: C1: PatchingStub for field
> access: not enough bytes
> 
> Hi Christoph,
> 
> thanks for reporting the bug
> https://bugs.openjdk.java.net/browse/JDK-8234645
> 
> Seems like the large offset fix in mem2reg and reg2mem missed the first
> patching stub in the long/double cases.
> We should have nop padding there, too (for same reason as for the 2nd
> patching stub).
> NativeMovRegMem should always consist of 2 instructions on arm32 in order
> to support larger offsets.
> 
> Webrev:
> http://cr.openjdk.java.net/~mdoerr/8234645_arm_padding/webrev.00/
> 
> May I ask you to test this fix? We don't have arm32 in our testing landscape.
> 
> Best regards,
> Martin