[11] 8207383: [Graal] SelfChangedCDS.java fails with "guarantee(disp == (intptr_t)(jint)disp) failed: must be 32-bit offset"

[Vladimir Kozlov]

Dean,

On 7/21/18 9:57 PM, dean.long at oracle.com wrote:
> On 7/21/18 5:37 PM, Vladimir Kozlov wrote:
>> To be clear. We don't use far call for AOT because in AOT code we call 
>> through trampoline anyway. Right?
> 
> Yes, we call through a "PLT".
> 
>>
>> My question is do we do that for all calls? Or only runtime calls?
>>
> 
> I believe we call through the PLT for everything except calls to code 
> that we know is in the AOT library, like Graal-generated stubs.
> This is a direct call:

Sorry, I was not clear. I asked about code generated by Graal JIT not 
for AOT. Your changes seem generate indirect call in all cases when 
scratch register is specified:

if (scratch != null && !GeneratePIC.getValue(crb.getOptions())) {

What about calls from nmethod to nmethod? They should not be far calls. 
I am not familiar with Graal and that is why I am asking.

Thanks,
Vladimir

> 
>      2883:       e8 98 1a 00 00          callq  4320 
> <Stub<ExceptionHandlerStub.exceptionHandler>>
> 
> This calls through a PLT:
> 
>      2c17:       e8 b4 15 00 00          callq  41d0 
> <M1_759_java.lang.invoke.MethodHandle.asType(Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/MethodHandle;_plt.entry> 
> 
> 
> Finally, we use trampolines when an nmethod needs to make a far call to 
> AOT code.
> 
> dl
> 
>> Thanks,
>> Vladimir
>>
>> On 7/21/18 11:52 AM, dean.long at oracle.com wrote:
>>> https://bugs.openjdk.java.net/browse/JDK-8207383
>>> http://cr.openjdk.java.net/~dlong/8207383/webrev/
>>>
>>> This fixes a regression caused by JDK-8181855.  The fix is to use a 
>>> scratch register to make far calls, but force a near call for AOT.
>>>
>>> Changeset based on contribution by Tom Rodriguez.
>>>
>>> dl
>