Respect TargetLibraryInfo CustomNames in getAllocationData

[Hal Finkel]

----- Original Message -----
> From: "Shea Levy" <shea at shealevy.com>
> To: llvm-commits at cs.uiuc.edu
> Sent: Saturday, February 8, 2014 9:55:38 PM
> Subject: Respect TargetLibraryInfo CustomNames in getAllocationData
> 
> Hi all,
> 
> Currently, getAllocationData in MemoryBuiltins.cpp (a helper used for
> functions like isAllocLikeFn) uses TargetLibraryInfo::getLibFunc on
> the
> passed in function name to determine if it corresponds to a
> LibFunc::Func. Unfortunately, getLibFunc looks up Funcs by
> StandardName
> (e.g. "malloc" -> LibFunc::Func::malloc) and doesn't respect any
> overridden names set by TargetLibraryInfo::setAvailableWithName. This
> is
> perhaps a bug in getLibFunc (if it isn't, getLibFunc should probably
> be
> static), but since existing code may depend on this behavior

Someone else may disagree ;) -- but I see no reason to do it this way. If the current code ignores name substitutions made using setAvailableWithName, then it is broken, and should be fixed. Please submit a patch to properly fix the code in getLibFunc, thanks!

 -Hal

> the
> attached patch instead modifies getAllocationData to compare the name
> associated with each of the Funcs in AllocationFnData with the
> passed-in
> function names, and if it matches (which will by the way never be
> true
> if the Func is not enabled for that TLI) then that is the Func used
> for
> the rest of the function.
> 
> My test case for this was compiling some IR that had a superfluous
> call
> to GC_malloc (return value unused) using a PassManagerBuilder at -O3.
> By
> default, the call wasn't optimized away (as expected), but when I set
> the builder's LibraryInfo to one with Func::malloc set to
> "GC_malloc",
> it was optimized away only with this patch applied.
> 
> Cheers,
> Shea Levy
> 
> P.S. I am not currently subscribed to the list, so please CC me in
> replies (though I'll check the list archives periodically for replies
> as
> well)
> 
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
> 

-- 
Hal Finkel
Assistant Computational Scientist
Leadership Computing Facility
Argonne National Laboratory