RFR: Add support for ARMv6 to ARM JIT

[Andrew Haley]

On 01/21/2015 05:06 PM, Edward Nevill wrote:
> Hi,
> 
> The following patch adds support for ARMv6 to the ARM JIT (previously known as the Thumb2 JIT).
> 
> http://openjdk.linaro.org/arm32jit/patches/6046.patch
> 
> The following ARM architectures are now supported
> 
> ARMv6 - Vanilla ARMv6 as on Raspberry PI (No Thumb2, No LDREXD/STREXD)
> ARMv6K - ARMv6 with MP support (No Thumb2, but has LDREXD/STREXD)
> ARMV6T2 - ARMv6 with Thumb2 and LDREXD/STREXD
> ARMV7 - all variants supported
> ARMV8 - all variants supported (in AARCH32 mode)
> 
> Note, because of the lack of properly working double/long atomic
> primitives on vanilla ARMv6 only non MP is supported on this. The
> Raspberry PI is single core so this is not a problem, it just uses
> LDM/STM or LDRD/STRD.
> 
> I have based the patches on the icedtea7 tree at
> http://icedtea.classpath.org/hg/icedtea7-forest/hotspot Is this the
> correct location for the tip of the icedtea7 development?

Umm, development?  OpenJDK 7 is only a few weeks from being orphaned!

> Because of the size of the changes I have introduced a new file
> arm32JIT.cpp rather than modifying the existing thumb2.cpp. This is
> switched on a symbol ARM32JIT. By default it will continue to build
> the Thumb2 JIT. To change it to build the ARM32 JIT by default add
> -DARM32JIT to CFLAGS in zeroshark.make as in the following patch.

I don't get this.  Surely we should have both, switchable at runtime.

Andrew.