Rejected AArch64 jdk8u backports

[Andrew Hughes]

On 11/05/2020 15:56, Andrew Haley wrote:
> I've been going though AArch64 jdk8u backports.
> The following backports should (probably) NOT be done in 8u; reasons follow.
> 
> 
> 8219006: AArch64: Register corruption in slow subtype check
> 
> Only affects debug builds; patch is fiddly and risky.
> 
> 8219698: aarch64: SIGILL triggered when specifying unsupported hardware features
> 
> Only happens due to user error: the problem is between keyboard and chair.
> 
> 8219993: AArch64: Compiled CI stubs are unsafely modified
> 
> This is a rather theoretical bug in that the AArch64 back end modifies
> stubs in a way that IMO doesn't conform to the AArch64 memory
> model. However, the fix is complicated and the problem has never
> manifested in any test cases, so it's better to leave it as it is in
> 8u.
> 
> 8222412: AARCH64: multiple instructions encoding issues
> 
> Big and intrusive, fixes no user-visible bugs, so not appropriate for
> 8u.
> 
> 8229118: [TESTBUG] serviceability/sa/ClhsdbFindPC fails on AArch64
> 
> Serviceability test. Not important.
> 
> 8232591: AArch64: Add missing match rules for smaddl, smsubl and smnegl
> 
> C2 enhancement. Might break things, small performance improvement,
> hard to test, so not for 8u.
> 
> 8233912: aarch64: minor improvements of atomic operations
> 
> Another rather theoretical patch that fixes no known bugs.
> 
> 8234794: AArch64: runtime/memory/ReadFromNoaccessArea.java crashes
> Summary: try to map CDS shared space at 4G aligned address on AArch64
> 
> Not applicable to 8u.
> 
> 8235385: AArch64: Crash on aarch64 JDK due to long offset
> 
> This is a real bug but it requires a very contrived test case to
> trigger it and the fix is complex. Probably not worth it.
> 
> 8237512: AArch64: aarch64TestHook leaks a BufferBlob
> 
> Only gets triggered in debug builds. Not important for 8u.
> 
> 8237524: AArch64: String.compareTo() may return incorrect result
> 
> Code being patched does not exist in 8u.
> 
> 8239787: AArch64: String.indexOf may incorrectly handle empty strings
> 
> Likewise
> 
> 8240353: AArch64: missing support for -XX:+ExtendedDTraceProbes in C1
> 
> Enhancement-only patch.
> 

Is there a reason a lot of recent AArch64 posts have also been CCed to
the 8u-dev list? Upstream 8u does not currently have an AArch64 port.

Thanks,
-- 
Andrew :)

Senior Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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