[clang] [llvm] [clang][ssaf] Implement JSON format for CallGraph summary (PR #189681)

[Balázs Benics via llvm-commits]

steakhal wrote:

I'm investigating a bot failure: https://lab.llvm.org/buildbot/#/builders/225/builds/4974
How I understand the failure is that the relative order of `caller()` and `polymorphic()` is unspecified. Consequently, we sometimes fail to match them in the expected order.
I'd expect a fix for this in the upcoming 10-15 minutes.

https://github.com/llvm/llvm-project/pull/189681