[llvm] [Sample Profile] Expand functionality of llvm-profdata function filter (PR #101615)

[via llvm-commits]

================
@@ -475,3 +478,40 @@ EXIT STATUS
 
 :program:`llvm-profdata` returns 1 if the command is omitted or is invalid,
 if it cannot read input files, or if there is a mismatch between their data.
+
+.. _profdata-canonical:
+
+SAMPLE PROFILE CANONICAL FUNCTION NAME
+--------------------------------------
+
+The canonical name of a (possibly inlined) function in sample profile is
+defined as the following:
----------------
WenleiHe wrote:

A few examples would be more clear and user friendly than the definitions below.  

(The definitions of text profile format is in SampleProfReader.h, even there we didn't use strict definitions.)

https://github.com/llvm/llvm-project/pull/101615