pytorch

57390116 - Restructure ShapeEnv so it uses GuardBuilder.SHAPE_ENV directly (#91055)

Restructure ShapeEnv so it uses GuardBuilder.SHAPE_ENV directly (#91055) The idea is to make ShapeEnv guards less of a one-off special snowflake, and integrate it more closely with the regular builder infrastructure. But it is not so easy: the shape env code has to live after tensor match code, because we need to know that the values in question are tensors before we start matching on them. So we introduce a new `shape_env_code` field to put the special shape env code, so we can add it to the final constructed code after tensor. Everything else works the obvious way. There's a new ShapeEnvSource for constructing the singleton SHAPE_ENV guard that drives the shape env guard construction. I added some more docs and also made the printed code for guards include the enclosing lambda for more clarity. Signed-off-by: Edward Z. Yang <ezyang@fb.com> Pull Request resolved: https://github.com/pytorch/pytorch/pull/91055 Approved by: https://github.com/albanD, https://github.com/voznesenskym