Brandt reported to me that he tried to create a macro instruction like this:

macro(LOAD_FAST_PUSH_NULL) = LOAD_FAST + PUSH_NULL;

and got an error from the cases generator. I've confirmed that this currently gives:

AssertionError: Push or pop above current stack level: stack_pointer[0]
...
AssertionError: Error writing macro LOAD_FAST_PUSH_NULL

This PR fixes that, by moving the "poke" code generation for all uops to the end, after the stack adjustment is done. I've added a test that confirms this works (the test elicits the same errors as above without the fixes).

None of the existing generated files are changed by this PR, since none of the current macro ops do this.

The fix looks a bit convoluted, in part due to the refactoring, in part because I added some extra assertions to ensure that _PUSH_FRAME, _POP_FRAME and SAVE_CURRENT_IP are only used in ways that don't violate the assumptions by the fix.

• Issue: Call design for Tier 2 (uops) interpreter #106581