bpo-46841: Use inline caching for `UNPACK_SEQUENCE` (GH-31591)

2 files changed, 26 insertions, 26 deletions

diff --git a/Python/ceval.c b/Python/ceval.c
index 4c0a71b..fe75782 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2758,22 +2758,22 @@ handle_eval_breaker:
             }
             STACK_GROW(oparg);
             Py_DECREF(seq);
+            JUMPBY(INLINE_CACHE_ENTRIES_UNPACK_SEQUENCE);
             DISPATCH();
         }
 
         TARGET(UNPACK_SEQUENCE_ADAPTIVE) {
             assert(cframe.use_tracing == 0);
-            SpecializedCacheEntry *cache = GET_CACHE();
-            if (cache->adaptive.counter == 0) {
+            _PyUnpackSequenceCache *cache = (_PyUnpackSequenceCache *)next_instr;
+            if (cache->counter == 0) {
                 PyObject *seq = TOP();
                 next_instr--;
-                _Py_Specialize_UnpackSequence(seq, next_instr, cache);
+                _Py_Specialize_UnpackSequence(seq, next_instr, oparg);
                 DISPATCH();
             }
             else {
                 STAT_INC(UNPACK_SEQUENCE, deferred);
-                cache->adaptive.counter--;
-                oparg = cache->adaptive.original_oparg;
+                cache->counter--;
                 JUMP_TO_INSTRUCTION(UNPACK_SEQUENCE);
             }
         }
@@ -2786,36 +2786,37 @@ handle_eval_breaker:
             SET_TOP(Py_NewRef(PyTuple_GET_ITEM(seq, 1)));
             PUSH(Py_NewRef(PyTuple_GET_ITEM(seq, 0)));
             Py_DECREF(seq);
+            JUMPBY(INLINE_CACHE_ENTRIES_UNPACK_SEQUENCE);
             NOTRACE_DISPATCH();
         }
 
         TARGET(UNPACK_SEQUENCE_TUPLE) {
             PyObject *seq = TOP();
-            int len = GET_CACHE()->adaptive.original_oparg;
             DEOPT_IF(!PyTuple_CheckExact(seq), UNPACK_SEQUENCE);
-            DEOPT_IF(PyTuple_GET_SIZE(seq) != len, UNPACK_SEQUENCE);
+            DEOPT_IF(PyTuple_GET_SIZE(seq) != oparg, UNPACK_SEQUENCE);
             STAT_INC(UNPACK_SEQUENCE, hit);
             STACK_SHRINK(1);
             PyObject **items = _PyTuple_ITEMS(seq);
-            while (len--) {
-                PUSH(Py_NewRef(items[len]));
+            while (oparg--) {
+                PUSH(Py_NewRef(items[oparg]));
             }
             Py_DECREF(seq);
+            JUMPBY(INLINE_CACHE_ENTRIES_UNPACK_SEQUENCE);
             NOTRACE_DISPATCH();
         }
 
         TARGET(UNPACK_SEQUENCE_LIST) {
             PyObject *seq = TOP();
-            int len = GET_CACHE()->adaptive.original_oparg;
             DEOPT_IF(!PyList_CheckExact(seq), UNPACK_SEQUENCE);
-            DEOPT_IF(PyList_GET_SIZE(seq) != len, UNPACK_SEQUENCE);
+            DEOPT_IF(PyList_GET_SIZE(seq) != oparg, UNPACK_SEQUENCE);
             STAT_INC(UNPACK_SEQUENCE, hit);
             STACK_SHRINK(1);
             PyObject **items = _PyList_ITEMS(seq);
-            while (len--) {
-                PUSH(Py_NewRef(items[len]));
+            while (oparg--) {
+                PUSH(Py_NewRef(items[oparg]));
             }
             Py_DECREF(seq);
+            JUMPBY(INLINE_CACHE_ENTRIES_UNPACK_SEQUENCE);
             NOTRACE_DISPATCH();
         }
 
@@ -5600,7 +5601,7 @@ MISS_WITH_CACHE(CALL)
 MISS_WITH_INLINE_CACHE(BINARY_OP)
 MISS_WITH_CACHE(COMPARE_OP)
 MISS_WITH_CACHE(BINARY_SUBSCR)
-MISS_WITH_CACHE(UNPACK_SEQUENCE)
+MISS_WITH_INLINE_CACHE(UNPACK_SEQUENCE)
 MISS_WITH_OPARG_COUNTER(STORE_SUBSCR)
 
 LOAD_ATTR_INSTANCE_VALUE_miss:
diff --git a/Python/specialize.c b/Python/specialize.c
index 1624f19..b88c5d5 100644
--- a/Python/specialize.c
+++ b/Python/specialize.c
@@ -67,7 +67,6 @@ static uint8_t cache_requirements[256] = {
     [PRECALL] = 2, /* _PyAdaptiveEntry and _PyObjectCache/_PyCallCache */
     [STORE_ATTR] = 1,  // _PyAdaptiveEntry
     [COMPARE_OP] = 1, /* _PyAdaptiveEntry */
-    [UNPACK_SEQUENCE] = 1,  // _PyAdaptiveEntry
 };
 
 Py_ssize_t _Py_QuickenedCount = 0;
@@ -2133,39 +2132,39 @@ unpack_sequence_fail_kind(PyObject *seq)
 #endif
 
 void
-_Py_Specialize_UnpackSequence(PyObject *seq, _Py_CODEUNIT *instr,
-                              SpecializedCacheEntry *cache)
+_Py_Specialize_UnpackSequence(PyObject *seq, _Py_CODEUNIT *instr, int oparg)
 {
-    _PyAdaptiveEntry *adaptive = &cache->adaptive;
+    assert(_PyOpcode_InlineCacheEntries[UNPACK_SEQUENCE] ==
+           INLINE_CACHE_ENTRIES_UNPACK_SEQUENCE);
+    _PyUnpackSequenceCache *cache = (_PyUnpackSequenceCache *)(instr + 1);
     if (PyTuple_CheckExact(seq)) {
-        if (PyTuple_GET_SIZE(seq) != adaptive->original_oparg) {
+        if (PyTuple_GET_SIZE(seq) != oparg) {
             SPECIALIZATION_FAIL(UNPACK_SEQUENCE, SPEC_FAIL_EXPECTED_ERROR);
             goto failure;
         }
         if (PyTuple_GET_SIZE(seq) == 2) {
-            *instr = _Py_MAKECODEUNIT(UNPACK_SEQUENCE_TWO_TUPLE,
-                                      _Py_OPARG(*instr));
+            *instr = _Py_MAKECODEUNIT(UNPACK_SEQUENCE_TWO_TUPLE, oparg);
             goto success;
         }
-        *instr = _Py_MAKECODEUNIT(UNPACK_SEQUENCE_TUPLE, _Py_OPARG(*instr));
+        *instr = _Py_MAKECODEUNIT(UNPACK_SEQUENCE_TUPLE, oparg);
         goto success;
     }
     if (PyList_CheckExact(seq)) {
-        if (PyList_GET_SIZE(seq) != adaptive->original_oparg) {
+        if (PyList_GET_SIZE(seq) != oparg) {
             SPECIALIZATION_FAIL(UNPACK_SEQUENCE, SPEC_FAIL_EXPECTED_ERROR);
             goto failure;
         }
-        *instr = _Py_MAKECODEUNIT(UNPACK_SEQUENCE_LIST, _Py_OPARG(*instr));
+        *instr = _Py_MAKECODEUNIT(UNPACK_SEQUENCE_LIST, oparg);
         goto success;
     }
     SPECIALIZATION_FAIL(UNPACK_SEQUENCE, unpack_sequence_fail_kind(seq));
 failure:
     STAT_INC(UNPACK_SEQUENCE, failure);
-    cache_backoff(adaptive);
+    cache->counter = ADAPTIVE_CACHE_BACKOFF;
     return;
 success:
     STAT_INC(UNPACK_SEQUENCE, success);
-    adaptive->counter = initial_counter_value();
+    cache->counter = initial_counter_value();
 }
 
 #ifdef Py_STATS