RFR (M): 8003853: specify offset of IC load in java_to_interp stub

[Christian Thalinger]

On Apr 23, 2013, at 11:00 AM, Christian Thalinger <christian.thalinger at oracle.com> wrote:

> The change looks good.  I have some minor comments though:
> src/share/vm/code/compiledIC.hpp:
> 
> +  static uint to_interp_stub_size();
> +  static uint reloc_to_interp_stub();
> +            stub_size  += CompiledStaticCall::to_interp_stub_size();
> +            reloc_size += CompiledStaticCall::reloc_to_interp_stub();
> stub_size and reloc_size are ints.  We should change the return type from uint to int.
> 
> src/cpu/x86/vm/compiledIC_x86.cpp:
>  108 uint CompiledStaticCall::to_interp_stub_size() {
>  109   return 10              // movl; jmp
>  110          LP64_ONLY(+5);  // movq (1+1+8); jmp (1+4)
>  111 }
> In expectancy of future changes we should do:
>  108 uint CompiledStaticCall::to_interp_stub_size() {
>  109   return NOT_LP64(10)    // movl; jmp
>  110          LP64_ONLY(15);  // movq (1+1+8); jmp (1+4)
>  111 }
> And one question unrelated to this change (because it was there before):
> 
> src/cpu/sparc/vm/compiledIC_sparc.cpp:
>  126 // Relocation entries for call stub, compiled java to interpreter.
>  127 uint CompiledStaticCall::reloc_to_interp_stub() {
>  128   return 10;  // 4 in emit_java_to_interp + 1 in Java_Static_Call
>  129 }
> Why does it say 5 relocations but returns 10?
> 
> Did someone try a Zero build?

Presumably not because Zero builds are broken right now.  I just filed:

8013067: Zero builds are broken after 8010862

-- Chris

> 
> -- Chris
> 
> On Apr 23, 2013, at 1:09 AM, "Lindenmaier, Goetz" <goetz.lindenmaier at sap.com> wrote:
> 
>> Hi all,
>>  
>> In the java_to_interp stub of CompiledStaticCalls one relocation is used to find
>> two code locations:
>> -          the beginning of the stub
>> -          the IC load instruction.
>> On x86 and sparc, the IC load instruction is the first instruction of the stub,
>> thus both locations have the same address.
>> On PPC, the IC load instruction is not the first instruction in the stub, thus
>> we must add an offset to the relocation to access it.
>>  
>> As the manipulation of  CompiledStaticCalls is in shared code, we would have
>> to introduce platform dependencies there.
>>  
>> This change moves the platform dependent code from CompiledStaticCall
>> to a new file compiledIC_<cpu>.cpp.  It also moves the code issuing the
>> stub from the ad file to this new file into the class CompiledStaticCall.
>> This removes redundancies between x86_64.ad and x86_32.ad.  Also,
>> ‘extern’ declarations in compile.cpp can be replaced by properly typed
>> Calls to methods in CompiledStaticCall.
>>  
>> Dean Long ran this change through JPRT with status OK (thanks!).
>>  
>> Please review and push this change.
>> http://cr.openjdk.java.net/~goetz/webrevs/8003853-3/
>>  
>> Best regards,
>>   Goetz Lindenmaier
> 

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