Mark undefined instructions as deopting to themselves

Summary: When CPython hands out the bytecode it will first do a de-opt on it: https://www.internalfb.com/code/fbsource/[241e0d0760d4c107a3c0ac2b4914524120b0c909]/third-party/python/3.12/Objects/codeobject.c?lines=1540&reveal=1540 This uses the de-opt table which only defines the known opcodes, meaning unknown opcodes get turned into 0's. We need CPython to at least define unknown opcodes to at least de-opt to themselves. Upstream PR: python/cpython#128044 Reviewed By: jbower-fb Differential Revision: D67350914 fbshipit-source-id: 0073efab52da1be775272e7dd9ae5a46468ccb10
facebookincubator · Dec 18, 2024 · 3d1b81e · 3d1b81e
1 parent 45f400c
commit 3d1b81e
Show file tree

Hide file tree

Showing 2 changed files with 65 additions and 0 deletions.
diff --git a/Include/internal/pycore_opcode.h b/Include/internal/pycore_opcode.h
diff --git a/Tools/build/generate_opcode_h.py b/Tools/build/generate_opcode_h.py
@@ -168,6 +168,9 @@ def main(opcode_py, outfile='Include/opcode.h',
         iobj.write("\nconst uint8_t _PyOpcode_Deopt[256] = {\n")
         for opt, deopt in sorted(deoptcodes.items()):
             iobj.write(f"    [{opt}] = {deopt},\n")
+        for i, name in enumerate(opname):
+            if not used[i]:
+                iobj.write(f"    [{i}] = {i},\n")
         iobj.write("};\n")
         iobj.write("#endif   // NEED_OPCODE_TABLES\n")