[llvm] [IRPGO][ValueProfile] Instrument virtual table address that could be used to do virtual table address comparision for indirect-call-promotion. (PR #66825)

[Snehasish Kumar via llvm-commits]

================
@@ -565,6 +674,13 @@ void InstrProfSymtab::finalizeSymtab() {
   llvm::sort(AddrToMD5Map, less_first());
   AddrToMD5Map.erase(std::unique(AddrToMD5Map.begin(), AddrToMD5Map.end()),
                      AddrToMD5Map.end());
+  // GlobalVariable address ranges should not overlap; so sort by either
----------------
snehasish wrote:

I think this is true for your vtable use case but not in general? E.g. Readonly string and other primitive constants can be merged such that the symbol names point to the same address range. 

https://github.com/llvm/llvm-project/pull/66825