RFR: 8329032: C2 compiler register allocation support for APX EGPRs [v2]

[Vladimir Kozlov]

On Fri, 14 Jun 2024 10:54:01 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Intel® Advanced Performance Extensions (Intel® APX) adds 16 new 64 bit general purpose register also known as Extended General Purpose Registers in IA-32e 64 bit mode.
>> 
>> Summary of changes introduced along with this patch:-
>> 
>> 1. C2 compiler register allocation support.
>> 2. Architecture state save restoration while transitioning from C1/C2 JIT compiled code to runtime services.
>> 3. Support new PUSH2/POP2 instructions along with push-pop acceleration hints (PPX) to optimize register save/restore operation.
>> 4. Applicable extensions to native interface used by runtime for patching instruction.
>> 
>> We plan to address C1 register support in subsequent patch as there are hard upper bound allocation limits
>> (currently set to r11) imposed by existing implementation of linear scan algorithm after which it reserves
>> remaining register for special purpose.
>> 
>> Patch has been regressed over stand alone test points after prioritizing EGPR allocations over existing GPR register by manually modifying the register sequences in relevant allocation class.
>> 
>> We plan to do thorough validation using [Intel's SDE](https://www.intel.com/content/www/us/en/download/684897/intel-software-development-emulator.html) during course of time and release incremental patches for bug fixes
>> found during testing.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   32-bit build fixes.

Some JVMCI tests failed in GHA on all x64 platforms:

# A fatal error has been detected by the Java Runtime Environment:
#
#  SIGSEGV (0xb) at pc=0x0000000109b66d2c, pid=19199, tid=26883
#
# JRE version: OpenJDK Runtime Environment (24.0) (fastdebug build 24-internal-jatin-bhateja)
# Java VM: OpenJDK 64-Bit Server VM (fastdebug 24-internal-jatin-bhateja, mixed mode, sharing, tiered, jvmci, compressed oops, compressed class ptrs, g1 gc, bsd-amd64)
# Problematic frame:
# V  [libjvm.dylib+0x117ed2c]  StackValue* StackValue::create_stack_value<RegisterMap>(ScopeValue*, unsigned char*, RegisterMap const*)+0x27c

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PR Comment: https://git.openjdk.org/jdk/pull/19042#issuecomment-2168465702