From 3d1b81e2c40a1da30ba6de84f6ceb7d585eded45 Mon Sep 17 00:00:00 2001
From: Dino Viehland <dinoviehland@meta.com>
Date: Wed, 18 Dec 2024 12:29:28 -0800
Subject: [PATCH] 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: https://github.com/python/cpython/pull/128044

Reviewed By: jbower-fb

Differential Revision: D67350914

fbshipit-source-id: 0073efab52da1be775272e7dd9ae5a46468ccb10
---
 Include/internal/pycore_opcode.h | 62 ++++++++++++++++++++++++++++++++
 Tools/build/generate_opcode_h.py |  3 ++
 2 files changed, 65 insertions(+)

diff --git a/Include/internal/pycore_opcode.h b/Include/internal/pycore_opcode.h
index e8258b3f90f..12b2861c455 100644
--- a/Include/internal/pycore_opcode.h
+++ b/Include/internal/pycore_opcode.h
@@ -241,6 +241,68 @@ const uint8_t _PyOpcode_Deopt[256] = {
     [UNPACK_SEQUENCE_TWO_TUPLE] = UNPACK_SEQUENCE,
     [WITH_EXCEPT_START] = WITH_EXCEPT_START,
     [YIELD_VALUE] = YIELD_VALUE,
+    [169] = 169,
+    [170] = 170,
+    [177] = 177,
+    [178] = 178,
+    [179] = 179,
+    [180] = 180,
+    [181] = 181,
+    [182] = 182,
+    [184] = 184,
+    [185] = 185,
+    [186] = 186,
+    [187] = 187,
+    [188] = 188,
+    [189] = 189,
+    [190] = 190,
+    [191] = 191,
+    [192] = 192,
+    [193] = 193,
+    [194] = 194,
+    [195] = 195,
+    [196] = 196,
+    [197] = 197,
+    [198] = 198,
+    [199] = 199,
+    [200] = 200,
+    [201] = 201,
+    [202] = 202,
+    [203] = 203,
+    [204] = 204,
+    [205] = 205,
+    [206] = 206,
+    [207] = 207,
+    [208] = 208,
+    [209] = 209,
+    [210] = 210,
+    [211] = 211,
+    [212] = 212,
+    [213] = 213,
+    [214] = 214,
+    [215] = 215,
+    [216] = 216,
+    [217] = 217,
+    [218] = 218,
+    [219] = 219,
+    [220] = 220,
+    [221] = 221,
+    [222] = 222,
+    [223] = 223,
+    [224] = 224,
+    [225] = 225,
+    [226] = 226,
+    [227] = 227,
+    [228] = 228,
+    [229] = 229,
+    [230] = 230,
+    [231] = 231,
+    [232] = 232,
+    [233] = 233,
+    [234] = 234,
+    [235] = 235,
+    [236] = 236,
+    [255] = 255,
 };
 #endif   // NEED_OPCODE_TABLES
 
diff --git a/Tools/build/generate_opcode_h.py b/Tools/build/generate_opcode_h.py
index 5be98100572..f784458a20f 100644
--- 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")