llvm dev - Aug 2006 - [LLVMdev] JIT and garbage collection

If I recall correctly, the garbage collector interface consists mostly of
some fuctions that one calls during execution to notify the collector
about a GC root. There's one othr thing that's needed if you do JIT
compilation: you have to garbage-collect the generated code.  This means
that the collector must be able to find where the pointers are in the
generated code together with metadata.

Is there any support for this?

Yes, the JIT implementation was recently improved to add support for
this. There's nothing you need to do (or emit). The JIT implementation
will automatically collect memory that is not being used. See the
JITMemoryManager in lib/ExecutionEngine/JIT/JITEmitter.cpp for details.

Reid.

On Sun, 2006-08-06 at 14:30 -0400, Hendrik Boom wrote:
> If I recall correctly, the garbage collector interface consists mostly of
> some fuctions that one calls during execution to notify the collector
> about a GC root. There's one othr thing that's needed if you do JIT
> compilation: you have to garbage-collect the generated code.  This means
> that the collector must be able to find where the pointers are in the
> generated code together with metadata.
> 
> Is there any support for this?
> 
> 
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

On Sun, 6 Aug 2006, Reid Spencer wrote:
> Yes, the JIT implementation was recently improved to add support for
> this. There's nothing you need to do (or emit). The JIT implementation
> will automatically collect memory that is not being used. See the
> JITMemoryManager in lib/ExecutionEngine/JIT/JITEmitter.cpp for details.
The JIT doesn't automatically do this.  I don't track where function 
pointers are and autoreclaim.  The client must specifically request that 
specific functions code be deallocated.

-Chris
> On Sun, 2006-08-06 at 14:30 -0400, Hendrik Boom wrote:
>> If I recall correctly, the garbage collector interface consists mostly
of
>> some fuctions that one calls during execution to notify the collector
>> about a GC root. There's one othr thing that's needed if you do
JIT
>> compilation: you have to garbage-collect the generated code.  This
means
>> that the collector must be able to find where the pointers are in the
>> generated code together with metadata.
>>
>> Is there any support for this?
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
-Chris

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