[Dynamo] Update the implementation of _debug_get_cache_entry_list (#108335)
In https://github.com/pytorch/pytorch/pull/106673 , I created a private API `_debug_get_cache_entry_list` to help pull out cache entries from compiled functions.
Recently, I find that @anijain2305 commented in the code that this API should be revisited, and so I created this PR.
First, this API cannot be removed even if cache entry becomes a first-class python class`torch._C._dynamo.eval_frame._CacheEntry`. The facts that `extra_index` is static, and `get_extra_state` is inline static, make them not accessible elsewhere. This API `_debug_get_cache_entry_list` is the only way for users to get all the cache entries from code.
Second, since the`torch._C._dynamo.eval_frame._CacheEntry` class is a python class, I simplified the C-part code, and remove the necessity of creating a namedtuple for this in the python code.
Third, I also add a small improvement, that if the argument is a function, we can automatically pass its `__code__` to the API.
The above change will slightly change the output, from list of named tuple to list of `torch._C._dynamo.eval_frame._CacheEntry`. I will update the corresponding docs that use this API.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/108335
Approved by: https://github.com/jansel, https://github.com/anijain2305
