[LLVMdev] Trouble using the MCJIT: "Target does not support MC emission" error

[Ralf Karrenberg]

Ah, now that makes sense. Guess I was a little over-eager with my
bugreport. Thanks! :)

However, I am now running into the same Problem as Matt ("Target does
not support MC emission!").

Best,
Ralf

Am 25.08.2011 19:32, schrieb Bruno Cardoso Lopes:
> Hi Ralf,
>
> FYI, old JIT doesn't support AVX at all, no encoding info, etc... The
> only way to use AVX+JIT is using MCJIT, which contains the correct
> encoding, but unfortunately the framework isn't good yet as the old
> one is.
>
> On Thu, Aug 25, 2011 at 10:12 AM, Ralf Karrenberg<Chareos at gmx.de>  wrote:
>> Hi Matt,
>>
>> I am unsure about MCJIT, but I guess the problem is the same.
>> Just like when invoking llc, you need to pass the information to use AVX
>> (llc -mattr=+avx).
>> I guess the corresponding code should look like this:
>>
>>      llvm::EngineBuilder engineBuilder(module);
>>      engineBuilder.setErrorStr(&eeError);
>>      engineBuilder.setEngineKind(llvm::EngineKind::JIT);
>>      engineBuilder.setUseMCJIT(true);
>>      engineBuilder.setMCPU("corei7-avx");
>>      std::vector<std::string>  attrs;
>>      attrs.push_back("avx");
>>      engineBuilder.setMAttrs(attrs);
>>      llvm::ExecutionEngine *ee = engineBuilder.create();
>>
>> Note that I have just today filed a bug report also related to jitted
>> AVX: http://llvm.org/bugs/show_bug.cgi?id=10742
>> Thus, it might very well be the case that I am also mistaken and need to
>> do something different.
>>
>> Best,
>> Ralf
>>
>> Am 25.08.2011 13:16, schrieb Matt Pharr:
>>> I'm trying to wire up some code to use the MC-based JIT; my understanding is that it should be able to JIT AVX code (and that the regular JIT cannot).  However, I'm getting the error "Target does not support MC emission!" when I call EngineBuilder::create().  I assume that I'm just not doing something necessary for initialization, but I'm not sure what it would be--I am calling all of:
>>>
>>>       llvm::InitializeNativeTarget();
>>>       llvm::InitializeAllTargetMCs();
>>>       LLVMLinkInMCJIT();
>>>       LLVMLinkInJIT();
>>>
>>> and the module I'm trying to load does have a reasonable target:
>>>
>>> target triple = "x86_64-apple-darwin11.0.0"
>>>
>>> I've attached a short test case that has the sequence of calls that I'm making and one of the bitcode files I'm trying to use.  I'd be happy for any guidance or suggestions.
>>>
>>> Thanks,
>>> -matt
>>>
>>>
>>>
>>>
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