[llvm] [llvm-profgen] Filter out ambiguous cold profiles during profile generation (PR #81803)

[Lei Wang via llvm-commits]

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@@ -975,6 +975,8 @@ class FunctionSamples {
     return CallsiteSamples;
   }
 
+  CallsiteSampleMap &getCallsiteSamples() { return CallsiteSamples; }
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wlei-llvm wrote:

yeah, we intentionally removed this.. I got it, will remove this.

>OTOH, I'm wondering do we actually need to filter call site (inlined) samples? 
>Also __cxx_global_var_init can inlined only into tls_init, but tls_ininit probably will never be inlined anywhere?

I do see `tls_init` appearing in the `CallsiteSamples`, presumably it can be inlined. 
Another thing which is specific to profile matching, we use the flattened profile for profile matching, so the inlinee's samples will be merged into top-level function, then used as the top-level function in profile matching(causing the issues we hit)

> I think only top level functions are indistinguishable, and inlinee's samples can be distinguished and still used by their inliner?
I think you are right, so we can leave it only for top level function if we can ensure it's also fine for profile matching. 



 



https://github.com/llvm/llvm-project/pull/81803