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

[Jiangli Zhou]

Hi,

Sorry for the delay. Here is the webrev for the open potion of the bug 
fix: http://cr.openjdk.java.net/~jiangli/7120481/webrev.00/. The c1 
changes are all done in the open code. New APIs are added to support 
more fine-grained memory barriers in c1. For example, ARM uses 'dmb st' 
before constructor return if it writes final.

Thanks,
Jiangli

On 02/09/2012 09:23 AM, Volker Simonis wrote:
> 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