Support RESUME op in Tier 2

- Add `#define TIER_ONE 1` to ceval.c
- Skip `#if TIER_ONE` blocks in code generator
- Use this in the bytecode definition for `RESUME`

Author: gvanrossum

Include/internal/pycore_opcode_metadata.h

@@ -135,6 +135,7 @@ dummy_func(
         }
 
         inst(RESUME, (--)) {
+            #if TIER_ONE
             assert(tstate->cframe == &cframe);
             assert(frame == cframe.current_frame);
             /* Possibly combine this with eval breaker */
@@ -143,7 +144,9 @@ dummy_func(
                 ERROR_IF(err, error);
                 next_instr--;
             }
-            else if (oparg < 2) {
+            else
+            #endif
+            if (oparg < 2) {
                 CHECK_EVAL_BREAKER();
             }
         }

Python/bytecodes.c

@@ -578,6 +578,7 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
     return _PyEval_EvalFrame(tstate, f->f_frame, throwflag);
 }
 
+#define TIER_ONE 1
 #include "ceval_macros.h"
 
 

Python/ceval.c

@@ -92,7 +92,7 @@ def variable_used_unspecialized(node: parsing.Node, name: str) -> bool:
             if text == "#if":
                 if (
                     i + 1 < len(node.tokens)
-                    and node.tokens[i + 1].text == "ENABLE_SPECIALIZATION"
+                    and node.tokens[i + 1].text in ("ENABLE_SPECIALIZATION", "TIER_ONE")
                 ):
                     skipping = True
             elif text in ("#else", "#endif"):

Python/executor_cases.c.h

@@ -120,7 +120,7 @@ def __init__(self, inst: parsing.InstDef):
     def is_viable_uop(self) -> bool:
         """Whether this instruction is viable as a uop."""
         dprint: typing.Callable[..., None] = lambda *args, **kwargs: None
-        if "PY_EXACT" in self.name:
+        if "RESUME" in self.name:
             dprint = print
 
         if self.name == "EXIT_TRACE":