bpo-46841: Inline cache for BINARY_SUBSCR.

Include/cpython/object.h

@@ -229,6 +229,13 @@ struct _typeobject{
  vectorcallfunc tp_vectorcall;
 };
 
+/* This struct is used by the specializer
+ * It should should be treated as an opaque blob
+ * by code other than the specializer and interpreter. */
+struct _specialization_cache{
+ PyObject *getitem;
+};
+
 /* The *real* layout of a type object when allocated on the heap */
 typedef struct _heaptypeobject{
  /* Note: there's a dependency on the order of these members
@@ -247,6 +254,7 @@ typedef struct _heaptypeobject{
  struct _dictkeysobject *ht_cached_keys;
  PyObject *ht_module;
  char *_ht_tpname; // Storage for "tp_name" see PyType_FromModuleAndSpec
+ struct _specialization_cache _spec_cache; // For use by the specializer.
  /* here are optional user slots, followed by the members. */
 } PyHeapTypeObject;
 

Include/internal/pycore_code.h

@@ -92,6 +92,15 @@ typedef struct{
 
 #define INLINE_CACHE_ENTRIES_COMPARE_OP CACHE_ENTRIES(_PyCompareOpCache)
 
+typedef struct{
+ _Py_CODEUNIT counter;
+ _Py_CODEUNIT type_version;
+ _Py_CODEUNIT _t1;
+ _Py_CODEUNIT func_version;
+} _PyBinarySubscrCache;
+
+#define INLINE_CACHE_ENTRIES_BINARY_SUBSCR CACHE_ENTRIES(_PyBinarySubscrCache)
+
 /* Maximum size of code to quicken, in code units. */
 #define MAX_SIZE_TO_QUICKEN 5000
 
@@ -323,7 +332,7 @@ extern int _Py_Specialize_LoadAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObjec
 extern int _Py_Specialize_StoreAttr(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, SpecializedCacheEntry *cache);
 extern int _Py_Specialize_LoadGlobal(PyObject *globals, PyObject *builtins, _Py_CODEUNIT *instr, PyObject *name);
 extern int _Py_Specialize_LoadMethod(PyObject *owner, _Py_CODEUNIT *instr, PyObject *name, SpecializedCacheEntry *cache);
-extern int _Py_Specialize_BinarySubscr(PyObject *sub, PyObject *container, _Py_CODEUNIT *instr, SpecializedCacheEntry *cache);
+extern int _Py_Specialize_BinarySubscr(PyObject *sub, PyObject *container, _Py_CODEUNIT *instr);
 extern int _Py_Specialize_StoreSubscr(PyObject *container, PyObject *sub, _Py_CODEUNIT *instr);
 extern int _Py_Specialize_Call(PyObject *callable, _Py_CODEUNIT *instr, int nargs,
  PyObject *kwnames, SpecializedCacheEntry *cache);

Lib/importlib/_bootstrap_external.py

@@ -389,7 +389,7 @@ def _write_atomic(path, data, mode=0o666):
 # Python 3.11a5 3480 (New CALL opcodes, second iteration)
 # Python 3.11a5 3481 (Use inline cache for BINARY_OP)
 # Python 3.11a5 3482 (Use inline caching for UNPACK_SEQUENCE and LOAD_GLOBAL)
-# Python 3.11a5 3483 (Use inline caching for COMPARE_OP)
+# Python 3.11a5 3483 (Use inline caching for COMPARE_OP and BINARY_SUBSCR)
 
 # Python 3.12 will start with magic number 3500
 

Lib/opcode.py

@@ -68,7 +68,7 @@ def jabs_op(name, op, entries=0):
 
 def_op('UNARY_INVERT', 15)
 
-def_op('BINARY_SUBSCR', 25)
+def_op('BINARY_SUBSCR', 25, 4)
 
 def_op('GET_LEN', 30)
 def_op('MATCH_MAPPING', 31)

Lib/test/test_capi.py

@@ -335,7 +335,7 @@ class C(): pass
  *_, count = line.split(b' ')
  count = int(count)
  self.assertLessEqual(count, i*5)
- self.assertGreaterEqual(count, i*5-1)
+ self.assertGreaterEqual(count, i*5-2)
 
  def test_mapping_keys_values_items(self):
  class Mapping1(dict):

Lib/test/test_sys.py

@@ -1501,7 +1501,9 @@ def delx(self): del self.__x
  '3P' # PyMappingMethods
  '10P' # PySequenceMethods
  '2P' # PyBufferProcs
- '6P')
+ '6P'
+ '1P' # Specializer cache
+ )
  class newstyleclass(object): pass
  # Separate block for PyDictKeysObject with 8 keys and 5 entries
  check(newstyleclass, s + calcsize(DICT_KEY_STRUCT_FORMAT) + 64 + 42*calcsize("n2P"))

Misc/NEWS.d/next/Core and Builtins/2022-02-28-15-46-36.bpo-46841.MDQoty.rst

@@ -0,0 +1 @@
+Use inline cache for :opcode:`BINARY_SUBSCR`.

Python/ceval.c

@@ -2102,25 +2102,24 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
  SET_TOP(res);
  if (res == NULL)
  goto error;
+ JUMPBY(INLINE_CACHE_ENTRIES_BINARY_SUBSCR);
  DISPATCH();
  }
 
  TARGET(BINARY_SUBSCR_ADAPTIVE){
-SpecializedCacheEntry *cache = GET_CACHE();
- if (cache->adaptive.counter == 0){
+_PyBinarySubscrCache *cache = (_PyBinarySubscrCache *)next_instr;
+ if (cache->counter == 0){
  PyObject *sub = TOP();
  PyObject *container = SECOND();
  next_instr--;
- if (_Py_Specialize_BinarySubscr(container, sub, next_instr, cache) < 0){
+ if (_Py_Specialize_BinarySubscr(container, sub, next_instr) < 0){
  goto error;
  }
  DISPATCH();
  }
  else{
  STAT_INC(BINARY_SUBSCR, deferred);
- cache->adaptive.counter--;
- assert(cache->adaptive.original_oparg == 0);
- /* No need to set oparg here; it isn't used by BINARY_SUBSCR */
+ cache->counter--;
  JUMP_TO_INSTRUCTION(BINARY_SUBSCR);
  }
  }
@@ -2146,6 +2145,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
  Py_DECREF(sub);
  SET_TOP(res);
  Py_DECREF(list);
+ JUMPBY(INLINE_CACHE_ENTRIES_BINARY_SUBSCR);
  NOTRACE_DISPATCH();
  }
 
@@ -2170,6 +2170,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
  Py_DECREF(sub);
  SET_TOP(res);
  Py_DECREF(tuple);
+ JUMPBY(INLINE_CACHE_ENTRIES_BINARY_SUBSCR);
  NOTRACE_DISPATCH();
  }
 
@@ -2188,18 +2189,22 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
  Py_DECREF(sub);
  SET_TOP(res);
  Py_DECREF(dict);
+ JUMPBY(INLINE_CACHE_ENTRIES_BINARY_SUBSCR);
  DISPATCH();
  }
 
  TARGET(BINARY_SUBSCR_GETITEM){
  PyObject *sub = TOP();
  PyObject *container = SECOND();
- SpecializedCacheEntry *caches = GET_CACHE();
- _PyAdaptiveEntry *cache0 = &caches[0].adaptive;
- _PyObjectCache *cache1 = &caches[-1].obj;
- PyFunctionObject *getitem = (PyFunctionObject *)cache1->obj;
- DEOPT_IF(Py_TYPE(container)->tp_version_tag != cache0->version, BINARY_SUBSCR);
- DEOPT_IF(getitem->func_version != cache0->index, BINARY_SUBSCR);
+ _PyBinarySubscrCache *cache = (_PyBinarySubscrCache *)next_instr;
+ uint32_t type_version = read32(&cache->type_version);
+ PyTypeObject *tp = Py_TYPE(container);
+ DEOPT_IF(tp->tp_version_tag != type_version, BINARY_SUBSCR);
+ assert(tp->tp_flags & Py_TPFLAGS_HEAPTYPE);
+ PyObject *cached = ((PyHeapTypeObject *)tp)->_spec_cache.getitem;
+ assert(PyFunction_Check(cached));
+ PyFunctionObject *getitem = (PyFunctionObject *)cached;
+ DEOPT_IF(getitem->func_version != cache->func_version, BINARY_SUBSCR);
  PyCodeObject *code = (PyCodeObject *)getitem->func_code;
  size_t size = code->co_nlocalsplus + code->co_stacksize + FRAME_SPECIALS_SIZE;
  assert(code->co_argcount == 2);
@@ -2218,6 +2223,7 @@ _PyEval_EvalFrameDefault(PyThreadState *tstate, _PyInterpreterFrame *frame, int
  new_frame->localsplus[i] = NULL;
  }
  _PyFrame_SetStackPointer(frame, stack_pointer);
+ frame->f_lasti += INLINE_CACHE_ENTRIES_BINARY_SUBSCR;
  new_frame->previous = frame;
  frame = cframe.current_frame = new_frame;
  CALL_STAT_INC(inlined_py_calls);
@@ -5605,7 +5611,7 @@ MISS_WITH_CACHE(PRECALL)
 MISS_WITH_CACHE(CALL)
 MISS_WITH_INLINE_CACHE(BINARY_OP)
 MISS_WITH_INLINE_CACHE(COMPARE_OP)
-MISS_WITH_CACHE(BINARY_SUBSCR)
+MISS_WITH_INLINE_CACHE(BINARY_SUBSCR)
 MISS_WITH_INLINE_CACHE(UNPACK_SEQUENCE)
 MISS_WITH_OPARG_COUNTER(STORE_SUBSCR)
 

Python/specialize.c

@@ -60,7 +60,6 @@ static uint8_t adaptive_opcodes[256] ={
 static uint8_t cache_requirements[256] ={
  [LOAD_ATTR] = 1, // _PyAdaptiveEntry
  [LOAD_METHOD] = 3, /* _PyAdaptiveEntry, _PyAttrCache and _PyObjectCache */
- [BINARY_SUBSCR] = 2, /* _PyAdaptiveEntry, _PyObjectCache */
  [STORE_SUBSCR] = 0,
  [CALL] = 2, /* _PyAdaptiveEntry and _PyObjectCache/_PyCallCache */
  [PRECALL] = 2, /* _PyAdaptiveEntry and _PyObjectCache/_PyCallCache */
@@ -385,6 +384,8 @@ optimize(SpecializedCacheOrInstruction *quickened, int len)
  if (adaptive_opcode){
  if (_PyOpcode_InlineCacheEntries[opcode]){
  instructions[i] = _Py_MAKECODEUNIT(adaptive_opcode, oparg);
+ previous_opcode = -1;
+ i += _PyOpcode_InlineCacheEntries[opcode];
  }
  else if (previous_opcode != EXTENDED_ARG){
  int new_oparg = oparg_from_instruction_and_update_offset(
@@ -553,6 +554,7 @@ initial_counter_value(void){
 #define SPEC_FAIL_SUBSCR_PY_SIMPLE 20
 #define SPEC_FAIL_SUBSCR_PY_OTHER 21
 #define SPEC_FAIL_SUBSCR_DICT_SUBCLASS_NO_OVERRIDE 22
+#define SPEC_FAIL_SUBSCR_NOT_HEAP_TYPE 23
 
 /* Binary op */
 
@@ -1335,9 +1337,11 @@ function_kind(PyCodeObject *code){
 
 int
 _Py_Specialize_BinarySubscr(
- PyObject *container, PyObject *sub, _Py_CODEUNIT *instr, SpecializedCacheEntry *cache)
+ PyObject *container, PyObject *sub, _Py_CODEUNIT *instr)
 {
- _PyAdaptiveEntry *cache0 = &cache->adaptive;
+ assert(_PyOpcode_InlineCacheEntries[BINARY_SUBSCR] ==
+ INLINE_CACHE_ENTRIES_BINARY_SUBSCR);
+ _PyBinarySubscrCache *cache = (_PyBinarySubscrCache *)(instr + 1);
  PyTypeObject *container_type = Py_TYPE(container);
  if (container_type == &PyList_Type){
  if (PyLong_CheckExact(sub)){
@@ -1364,26 +1368,30 @@ _Py_Specialize_BinarySubscr(
  PyTypeObject *cls = Py_TYPE(container);
  PyObject *descriptor = _PyType_Lookup(cls, &_Py_ID(__getitem__));
  if (descriptor && Py_TYPE(descriptor) == &PyFunction_Type){
+ if (!(container_type->tp_flags & Py_TPFLAGS_HEAPTYPE)){
+ SPECIALIZATION_FAIL(BINARY_SUBSCR, SPEC_FAIL_SUBSCR_NOT_HEAP_TYPE);
+ goto fail;
+ }
  PyFunctionObject *func = (PyFunctionObject *)descriptor;
- PyCodeObject *code = (PyCodeObject *)func->func_code;
- int kind = function_kind(code);
+ PyCodeObject *fcode = (PyCodeObject *)func->func_code;
+ int kind = function_kind(fcode);
  if (kind != SIMPLE_FUNCTION){
  SPECIALIZATION_FAIL(BINARY_SUBSCR, kind);
  goto fail;
  }
- if (code->co_argcount != 2){
+ if (fcode->co_argcount != 2){
  SPECIALIZATION_FAIL(BINARY_SUBSCR, SPEC_FAIL_WRONG_NUMBER_ARGUMENTS);
  goto fail;
  }
  assert(cls->tp_version_tag != 0);
-cache0->version = cls->tp_version_tag;
+write32(&cache->type_version, cls->tp_version_tag);
  int version = _PyFunction_GetVersionForCurrentState(func);
  if (version == 0 || version != (uint16_t)version){
  SPECIALIZATION_FAIL(BINARY_SUBSCR, SPEC_FAIL_OUT_OF_VERSIONS);
  goto fail;
  }
-cache0->index = version;
-cache[-1].obj.obj = descriptor;
+cache->func_version = version;
+((PyHeapTypeObject *)container_type)->_spec_cache.getitem = descriptor;
  *instr = _Py_MAKECODEUNIT(BINARY_SUBSCR_GETITEM, _Py_OPARG(*instr));
  goto success;
  }
@@ -1392,12 +1400,12 @@ _Py_Specialize_BinarySubscr(
 fail:
  STAT_INC(BINARY_SUBSCR, failure);
  assert(!PyErr_Occurred());
-cache_backoff(cache0);
+cache->counter = ADAPTIVE_CACHE_BACKOFF;
  return 0;
 success:
  STAT_INC(BINARY_SUBSCR, success);
  assert(!PyErr_Occurred());
-cache0->counter = initial_counter_value();
+cache->counter = initial_counter_value();
  return 0;
 }