[llvm] [llvm][AsmPrinter] Call graph section format. (PR #159866)

[Prabhu Rajasekaran via llvm-commits]

================
@@ -0,0 +1,29 @@
+# .callgraph Section Layout
+
+The `.callgraph` section is used to store call graph information for each function, which can be used for post-link analyses and optimizations. The section contains a series of records, with each record corresponding to a single function.
----------------
Prabhuk wrote:

Removed the part about post-link analyses.

https://github.com/llvm/llvm-project/pull/159866