GH-125837: Split `LOAD_CONST` into three. (GH-125972)

* Add LOAD_CONST_IMMORTAL opcode

* Add LOAD_SMALL_INT opcode

* Remove RETURN_CONST opcode

1 files changed, 14 insertions, 0 deletions

diff --git a/Python/specialize.c b/Python/specialize.c
index 4b33a468733..ae47809305a 100644
--- a/Python/specialize.c
+++ b/Python/specialize.c
@@ -442,11 +442,13 @@ _PyCode_Quicken(PyCodeObject *code)
 {
     #if ENABLE_SPECIALIZATION
     int opcode = 0;
+    int oparg = 0;
     _Py_CODEUNIT *instructions = _PyCode_CODE(code);
     /* The last code unit cannot have a cache, so we don't need to check it */
     for (int i = 0; i < Py_SIZE(code)-1; i++) {
         opcode = instructions[i].op.code;
         int caches = _PyOpcode_Caches[opcode];
+        oparg = (oparg << 8) | instructions[i].op.arg;
         if (caches) {
             // The initial value depends on the opcode
             switch (opcode) {
@@ -465,6 +467,18 @@ _PyCode_Quicken(PyCodeObject *code)
             }
             i += caches;
         }
+        else if (opcode == LOAD_CONST) {
+            /* We can't do this in the bytecode compiler as
+             * marshalling can intern strings and make them immortal. */
+
+            PyObject *obj = PyTuple_GET_ITEM(code->co_consts, oparg);
+            if (_Py_IsImmortal(obj)) {
+                instructions[i].op.code = LOAD_CONST_IMMORTAL;
+            }
+        }
+        if (opcode != EXTENDED_ARG) {
+            oparg = 0;
+        }
     }
     #endif /* ENABLE_SPECIALIZATION */
 }