[LLVMdev] how to set -pre-ra-sched from code?

[Andrew Friedley]

Sanjiv Gupta wrote:
> On Wed, 2010-04-14 at 11:33 -0400, Andrew Friedley wrote:
>> I've found that I need to set the -pre-RA-sched parameter when using 
>> tools like llc to get the kind of instruction scheduling I want.
>>
>> However I'm normally generating and running code on the fly using the 
>> JIT, and can't figure out how to set the -pre-RA-sched option anywhere 
>> other than on the command line for the provided tools.  So what code 
>> would I write (or where is the API?) to change the pre-regalloc 
>> instruction scheduler algorithm?
> 
> Does this thing below in TargetLowering help?
> 
> /// setSchedulingPreference - Specify the target scheduling preference.
>   void setSchedulingPreference(SchedPreference Pref) 

Thanks!  That doesn't look like what -pre-RA-sched eventually maps to, 
but it looks like the switch I want to change.  Pardon my ignorance, but 
I have no idea how I'm supposed to get to a point where I can call this 
when all I have is a module and an execution engine.

Better yet, how would I go about figuring this out from the 
documentation?  I'm having no luck at all finding these things.

Andrew