Add frame/recompile counter to all log messages in tracing context (#107530)
All log messages that occur while running Dynamo compilation now have `[X/Y]` added to the beginning of their message. X represents the frame being compiled, while Y says which compilation of the frame. For example, if you are debugging a frame that is repeatedly recompiling, you can look for N/0, N/1, N/2, etc. for the same N. Here is what the logs look like as you transition from one frame to another:
<img width="1372" alt="image" src="https://github.com/pytorch/pytorch/assets/13564/4897e368-1e50-4807-b342-54e911bcf087">
To accurately get this prefix added to all messages, I had to expand the scope of the `tracing` context manager. Its scope now coincides with `log_compilation_event`. To do this, I had to populate fake mode lazily in the TracingContext, since it isn't created until later, inside the OutputGraph.
This subsumes the previous X.Y logging that was solely for dynamic shapes.
Unfortunately I had to reindent some stuff. Review the diff with whitespace off.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107530
Approved by: https://github.com/anijain2305
ghstack dependencies: #107505, #107516
