[llvm] [SampleProfile] Support MD5-based ProfileSymbolList (PR #210235)

[David Li via llvm-commits]

================
@@ -1688,19 +1696,45 @@ class ProfileSymbolList {
     Syms.insert(Name.copy(Allocator));
   }
 
-  bool contains(StringRef Name) { return Syms.count(Name); }
+  bool contains(StringRef Name) const {
+    return Syms.count(Name) || ColdGUIDTable.contains(llvm::MD5Hash(Name));
----------------
david-xl wrote:

Should this be based on SecFlag setting?  In the current implementation, Checking strings is wasteful for MD5 (which will be the default in the future ?).

https://github.com/llvm/llvm-project/pull/210235