RFR: 8209093 - JEP 340: One AArch64 Port, Not Two

[Boris Ulasevich]

Hi Bob,

Thank you for this job!
I have started testing. Will come back with results next week :)
The changes is Ok for me. Please see some minor comments below.

regards,
Boris

On 17.09.2018 20:49, Aleksey Shipilev wrote:
> On 09/17/2018 07:00 PM, Vladimir Kozlov wrote:
>> On 9/17/18 9:20 AM, Bob Vandette wrote:
>>> Please review the changes related to JEP 340 which remove the second
>>> 64-bit ARM port from the JDK.>>
>>> http://cr.openjdk.java.net/~bobv/8209093/webrev.01
> 
> I read through the webrev, and it seems to be the clean removal. It also feels
> very satisfying to drop 15 KLOC of ifdef-ed code.
> 
> Minor nits:
> 
>   *) In src/hotspot/cpu/arm/c1_LIRAssembler_arm.cpp and
> src/hotspot/cpu/arm/interp_masm_arm.cpp we have "#if defined(ASSERT)", which cab
> be just "#ifdef ASSERT" now
> 
>   *) Ditto in src/hotspot/cpu/arm/jniFastGetField_arm.cpp we have "#if
> defined(__ABI_HARD__)"
> 
>   *) In src/hotspot/cpu/arm/macroAssembler_arm.hpp, the comment below seems to
> apply to AArch64 only. 

Yes, the note looks like AArch64 specific comment, but I think it is 
valid for arm32 too. So the change is Ok for me.

> Yet, only the first line of the comment is removed. I
> think we should instead convert that comment into "TODO:" mentioning this might
> be revised after AArch64 removal?
> 
>   992   void branch_if_negative_32(Register r, Label& L) {
>   993     // Note about branch_if_negative_32() / branch_if_any_negative_32()
> implementation for AArch64:
>   994     // tbnz is not used instead of tst & b.mi because destination may be
> out of tbnz range (+-32KB)
>   995     // since these methods are used in LIR_Assembler::emit_arraycopy() to
> jump to stub entry.
>   996     tst_32(r, r);
>   997     b(L, mi);
>   998   }
> 
>   *) In src/hotspot/cpu/arm/stubGenerator_arm.cpp, lines L1204..1205, L1435..1436
> can be merged together:
> 
> 1203   // Generate the inner loop for shifted forward array copy (unaligned copy).
> 1204   // It can be used when bytes_per_count < wordSize, i.e.
> 1205   //  byte/short copy
> 
> 1434   // Generate the inner loop for shifted backward array copy (unaligned copy).
> 1435   // It can be used when bytes_per_count < wordSize, i.e.
> 1436   //  byte/short copy
> 
> 
>   *) In src/hotspot/cpu/arm/stubGenerator_arm.cpp, the comment changed
> incorrectly around L3363?

I believe both (L3188 and L3363) comments should mention SP[0] (not R4) 
as an input parameter now.

>    - //    R4 (AArch64) / SP[0] (32-bit ARM) -  element count (32-bit int)
>    + //    R4    -  element count (32-bit int)
> 
> 
>   *) In src/hotspot/cpu/arm/templateInterpreterGenerator_arm.cpp, "R4"/"R5"
> comments are missing:
> 
>    - const Register Rsig_handler    = AARCH64_ONLY(R21) NOT_AARCH64(Rtmp_save0 /*
> R4 */);
>    - const Register Rnative_code    = AARCH64_ONLY(R22) NOT_AARCH64(Rtmp_save1 /*
> R5 */);
>    + const Register Rsig_handler    = Rtmp_save0;
>    + const Register Rnative_code    = Rtmp_save1;
> 
> Thanks,
> -Aleksey
>