RFR(M): 8207343: Automate vtable/itable stub size calculation

[Schmidt, Lutz]

Hi Boris,
thanks for looking at this. I will respond to your comments in more detail next week. I'm on vacation this week.
Thanks,
Lutz

On 05.08.18, 19:08, "Boris Ulasevich" <boris.ulasevich at bell-sw.com> wrote:

    Hi Lutz,
    
       I have run jtreg with your change and do not see new fails (test that 
    fails on aarch64 is excluded for 32 bit platforms).
    
       I am OK with your change (I'm not a reviewer). But description and 
    variable name in VtableStub::pd_code_alignment function looks strange 
    for me. Raspberry Pi2 ARM1176JZF-S processor has a cache line length of 
    32 bytes, and, as I know, icache line size is not a constant for ARM32 
    architecture.
    
    regards,
    Boris
    
    On 02.08.2018 15:02, Schmidt, Lutz wrote:
    > Hi Zhongwei,
    > 
    > thank you for testing aarch64. Given my lack of expertise, I am surprised there are only those two issues.
    > Ad 1.: fixed. The declaration just a few lines above was forgotten to adapt.
    > Ad 2.: adapted. I pushed the estimate to 152 bytes. I expected this value would require some adjustment.
    > 
    > Please find a new webrev with the changes at http://cr.openjdk.java.net/~lucy/webrevs/8207343.01
    > 
    > Best Regards,
    > Lutz
    > 
    > On 02.08.18, 04:45, "Zhongwei Yao" <Zhongwei.Yao at arm.com> wrote:
    > 
    >      Hi, Lutz,
    >      
    >      I have tested it on aarch64 by running jtreg tests. And find two tiny issues in vtableStubs_aarch64.cpp's VtableStubs::create_itable_stub function:
    >      1. typecheckSize on line 212 is not defined.
    >      2. estimate on line 211 is not large enough, I get 148 in gc/g1/TestFromCardCacheIndex.java case. Here is the assertion failure from that case:
    >          assert(slop_delta >= 0) failed: itable #3: Code size estimate (140) for lookup_interface_method too small, required: 148
    >      
    >      However, I don't have tested the modification in vtableStubs_arm.cpp due to I don't have an arm32 environment at hand.
    >      
    >      --
    >      Best regards,
    >      Zhongwei
    >      
    >      ________________________________________
    >      From: hotspot-compiler-dev <hotspot-compiler-dev-bounces at openjdk.java.net> on behalf of Schmidt, Lutz <lutz.schmidt at sap.com>
    >      Sent: Monday, July 30, 2018 3:57:05 PM
    >      To: hotspot-compiler-dev at openjdk.java.net
    >      Subject: RFR(M): 8207343: Automate vtable/itable stub size calculation
    >      
    >      Dear all,
    >      
    >      may I please request reviews for this change:
    >      
    >      Bug:    https://bugs.openjdk.java.net/browse/JDK-8207343
    >      Webrev: http://cr.openjdk.java.net/~lucy/webrevs/8207343.00/
    >      
    >      With this change, I try to get rid of the a-priory size guessing for vtable and itable stubs. Please refer to the bug description for all the details. I didn't want to duplicate that text.
    >      
    >      ARM and AARCH64 help requested!
    >      The edits in vtableStubs_aarch64.cpp and vtableStubs_arm.cpp are made blindfolded. I am neither an ARM expert nor do I have build or test hardware available. I would be very grateful if one of the ARM gurus could please fill in for me.
    >      
    >      Thank you!
    >      Lutz
    >      
    >      
    >      
    >