Please review fix for 7120481 storeStore barrier in constructor with final field

[Volker Simonis]

Hi,
could you please put at least the open part of the webrev onto a
webserver visible from outside Oracle.

Thank  you and best regards,
Volker


On Thu, Feb 9, 2012 at 12:35 AM, Jiangli Zhou <jiangli.zhou at oracle.com> wrote:
> Hi,
>
> Please review the following webrevs for 7120481 storeStore barrier in
> constructor with final field:
>
> http://javaweb.sfbay.sun.com/~jianzhou/webrev.storestore/
> http://javaweb.sfbay.sun.com/~jianzhou/webrev.storestore.closed/
>
> Both c1 and the template interpreter are fixed to add the needed memory
> barrier. For a constructor that writes final field, a release barrier is
> added in the compiled method before the constructor returns if the
> constructor is not inlined. When the constructor is inlined, a release
> barrier is added at the end of the inlined constructor. The changes are done
> in the shared c1 code only, the platform specific code already knows whether
> memory barrier instructions should be generated for the platform. Following
> are ARM examples of a compiled constructor that writes final field after the
> fix. For the template interpreter, a new opcode '_return_with_membar' is
> added. During method rewriting, the VM detects if a constructor writes
> final. If so, the _return opcode is changed into _return_with_membar for the
> constructor. The ARM and PPC template interpreter code are changed to issue
> a storesotre barrier for the new opcode.
>
> Not inlined:
>
>   0x41386450: mov    r1, r0
>   0x41386454: mov    r0, r1          ;*invokespecial <init>
>                                         ; - HasFinal::<init>@1 (line 19)
>   0x41386458: str    r1, [sp, #16]
>   0x4138645c: bl    0x41325d00      ; OopMap{[16]=Oop off=48}
>                                         ;*invokespecial <init>
>                                         ; - HasFinal::<init>@1 (line 19)
>                                         ;   {optimized virtual_call}
>   0x41386460: mov    r0, #100    ; 0x64
>   0x41386464: ldr    r1, [sp, #16]
>   0x41386468: str    r0, [r1, #8]    ;*putfield x
>                                         ; - HasFinal::<init>@7 (line 20)
>   0x4138646c: dmb    sy
>   0x41386470: add    sp, sp, #24
>   0x41386474: pop    {fp, lr}
>   0x41386478: movw    ip, #53248    ; 0xd000
>   0x4138647c: movt    ip, #16397    ; 0x400d
>   0x41386480: ldr    ip, [ip]        ;   {poll_return}
>   0x41386484: bx    lr
>   0x41386488: nop            ; (mov r0, r0)
>
>
> Inlined:
>
>   0x413797e0: mov    r1, r0
>   0x413797e4: mov    r0, r1          ;*invokespecial <init>
>                                         ; - HasFinal::<init>@1 (line 19)
>                                         ; - FinalTest::main at 25 (line 11)
>   0x413797e8: str    r1, [sp, #32]
>   0x413797ec: bl    0x41318d00      ; OopMap{[32]=Oop off=272}
>                                         ;*invokespecial <init>
>                                         ; - HasFinal::<init>@1 (line 19)
>                                         ; - FinalTest::main at 25 (line 11)
>                                         ;   {optimized virtual_call}
>   0x413797f0: mov    r0, #100    ; 0x64
>   0x413797f4: ldr    r1, [sp, #32]
>   0x413797f8: str    r0, [r1, #8]    ;*putfield x
>                                         ; - HasFinal::<init>@7 (line 20)
>                                         ; - FinalTest::main at 25 (line 11)
>   0x413797fc: dmb    sy
>   0x41379800: movw    r0, #23416    ; 0x5b78
>                                         ;   {oop(a 'java/lang/Class' =
> 'FinalTest')}
>   0x41379804: movt    r0, #17206    ; 0x4336
>   0x41379808: str    r1, [r0, #104]    ; 0x68
>
> Thanks,
>
> Jiangli