[Mesa-dev] [PATCH 1/2] radeonsi: Cache LLVMTargetMachine object in si_screen

[Michel Dänzer]

On 14.01.2015 04:07, Tom Stellard wrote:
> On Tue, Jan 13, 2015 at 06:47:00PM +0900, Michel Dänzer wrote:
>> On 07.01.2015 10:10, Michel Dänzer wrote:
>>> On 07.01.2015 06:33, Tom Stellard wrote:
>>>> On Wed, Dec 24, 2014 at 12:48:31PM +0900, Michel Dänzer wrote:
>>>>> On 24.12.2014 02:49, Tom Stellard wrote:
>>>>>> Rather than building a new one every compile.  This should reduce some
>>>>>> of the overhead of compiling shaders.
>>>>>
>>>>> Thanks, though unfortunately it doesn't seem to make much difference for
>>>>> piglit for me.
>>>>>
>>>>>
>>>>>> One consequence of this change is that we lose the MachineInstrs dumps
>>>>>> when dumping the shaders via R600_DEBUG.  The LLVM IR and assembly is
>>>>>> still dumped, and if you still want to see the MachineInstr dump, you
>>>>>> can run the dumped LLVM IR through llc.
>>>>>
>>>>> Sounds reasonable, but...
>>>>>
>>>>>
>>>>>> @@ -503,5 +510,12 @@ struct pipe_screen *radeonsi_screen_create(struct radeon_winsys *ws)
>>>>>>  	/* Create the auxiliary context. This must be done last. */
>>>>>>  	sscreen->b.aux_context = sscreen->b.b.context_create(&sscreen->b.b, NULL);
>>>>>>  
>>>>>> +	/* Initialize LLVM TargetMachine */
>>>>>> +	r600_target = radeon_llvm_get_r600_target();
>>>>>> +	sscreen->tm = LLVMCreateTargetMachine(r600_target, "r600--",
>>>>>> +				r600_get_llvm_processor_name(sscreen->b.family),
>>>>>> +				"+DumpCode", LLVMCodeGenLevelDefault, LLVMRelocDefault,
>>>>>> +				LLVMCodeModelDefault);
>>>>>> +
>>>>>>  	return &sscreen->b.b;
>>>>>>  }
>>>>>
>>>>> ... since you pass "+DumpCode" here, the MachineInstrs are actually
>>>>> always dumped unconditionally. With that fixed, this patch is
>>>>>
>>>>
>>>> I've removed the MF.dump() call in the LLVM tree, so this won't happen.
>>>
>>> That won't help people using LLVM 3.4 (or 3.5?), will it?
>>
>> Tom, users of LLVM 3.4/5 get spammed by MachineInstr dumps with this
>> change, right? Do you have a plan to address this?
>>
> 
> I disabled target machine caching for < LLVM 3.6, so this shouldn't be
> an issue.

I see, thanks for the clarification.

BTW, do you think it would also be possible to keep around the LLVM
module / context between shader compilations?


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer