[llvm] [GSYM] Callsites: Add data format support and loading from YAML (PR #109781)

[Kyungwoo Lee via llvm-commits]

================
@@ -32,6 +33,8 @@ raw_ostream &llvm::gsym::operator<<(raw_ostream &OS, const FunctionInfo &FI) {
     OS << FI.OptLineTable << '\n';
   if (FI.Inline)
     OS << FI.Inline << '\n';
+  if (FI.CallSites)
+    OS << *FI.CallSites << '\n';
----------------
kyulee-com wrote:

`CallSites` is an optional value like `Inline` above. I wonder why this pointer pattern is different. Perhaps `Inline` is a bug? Do we actually have a test coverage on this code?

https://github.com/llvm/llvm-project/pull/109781