[RFR] jdk9.0.4+12 + functionality

[Bob Vandette]

> On Apr 17, 2018, at 4:23 AM, Andrew Dinn <adinn at redhat.com> wrote:
> 
> On 16/04/18 23:58, Bob Vandette wrote:
>> Is there a reason that the fully functioning 32-bit ARM port that already exists in JDK 9
>> can’t be used as the basis for this work?  
> 
> Well, I guess the main one is that no one working on the AArch32 project
> has any real knowledge of the 32-bit arm (qua, arm project) port.

Other than MacroAssembler syntax, how much unique knowledge does
one port really require over another?  These ports all have to do the same thing
forcing the implementations to be pretty similar.

> 
> However, another reason to not go that route is that the AArch32 port
> was derived from the AArch64 port which was, in turn, derived from the
> x86 port. Whatever the provenance of the (32- or 64-bit) arm code it
> differs in significant ways from the x86 code.


The 32-bit ARM port has been around since the JDK 8 days, although
the sources were maintained in the closed forest.  This port was not
derived from the x86 port or the aarch64 port.  The aarch64 port was
derived from the arm32 port in order to make it easier to maintain both ports.

The 32-bit ARM port has been well tested for many many release including
leading up to the completion of JDK 9 and has been used in countless embedded
products.  It was a last minute decision by Oracle to discontinue the delivery of
binaries so the port is pretty up-to-date.

Bob.


> 
> I say that because, previously, when I have looked at patches which
> update x86, sparc and arm with a view to adding the missing AArch64
> code, I have *always* found that the patch required for AArch64 is much
> closer in format to the x86 code (or even the sparc code) than it is to
> the corresponding (64 bit) arm port code. I expect that the same will
> apply to the AArch32 code. Your mileage (and, no doubt, your
> understanding of the inner workings of the arm port) may vary.
> 
> regards,
> 
> 
> Andrew Dinn
> -----------
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