[clang] [lld] [llvm] Adding Matching and Inference Functionality to Propeller (PR #139008)

[Sriraman Tallam via cfe-commits]

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@@ -1688,6 +1688,11 @@ def fprofile_sample_accurate : Flag<["-"], "fprofile-sample-accurate">,
                as cold. Otherwise, treat callsites without profile samples as if
                we have no profile}]>,
    MarshallingInfoFlag<CodeGenOpts<"ProfileSampleAccurate">>;
+def fpropeller_profile_use_EQ : Joined<["-"], "fpropeller-profile-use=">,
+    Group<f_Group>, Visibility<[ClangOption, CC1Option, CLOption]>, 
+    MetaVarName<"<pathname>">,
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tmsri wrote:

So, we want :

1.  Another option to expose raw propeller profiles, MBB hashes and counts to the compiler.  
2.  It would be mutually exclusive to -fbasic-block-sections=list options

I want to have a discussion on how much of a maintenance burden this would cause.  This is because Propeller will now do code layout in two different ways.  With stale profiles, the compiler will do it.   By default, the offline tool would do it.  For future optimizations, we need to figure out how to support two paths.  @rlavaee @shenhanc78 

Can we expose raw profiles using -fbasic-blocks-sections=list= itself?  Do we need a new option?   I like the stale profile matching ideas but I am not sure adding a new flag and a new file is the way to go forward.




https://github.com/llvm/llvm-project/pull/139008