https://github.com/python/cpython/commit/a4fd7aa4a6420cef1c22ec64eab54d8aea41cc57
commit: a4fd7aa4a6420cef1c22ec64eab54d8aea41cc57
branch: main
author: Mark Shannon <[email protected]>
committer: markshannon <[email protected]>
date: 2024-08-21T15:52:04+01:00
summary:
GH-115776: Allow any fixed sized object to have inline values (GH-123192)
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2024-08-21-08-53-00.gh-issue-115776.9A7Dv_.rst
M Include/internal/pycore_object.h
M Objects/object_layout.md
M Objects/typeobject.c
M Python/bytecodes.c
M Python/executor_cases.c.h
M Python/gc.c
M Python/gc_free_threading.c
M Python/generated_cases.c.h
M Python/optimizer_bytecodes.c
M Python/optimizer_cases.c.h
M Python/specialize.c
M Tools/gdb/libpython.py
diff --git a/Include/internal/pycore_object.h b/Include/internal/pycore_object.h
index ee33da77f01f2d..0f2de6fd28f56e 100644
--- a/Include/internal/pycore_object.h
+++ b/Include/internal/pycore_object.h
@@ -803,10 +803,11 @@ _PyObject_GetManagedDict(PyObject *obj)
static inline PyDictValues *
_PyObject_InlineValues(PyObject *obj)
{
+ PyTypeObject *tp = Py_TYPE(obj);
+ assert(tp->tp_basicsize > 0 && tp->tp_basicsize % sizeof(PyObject *) == 0);
assert(Py_TYPE(obj)->tp_flags & Py_TPFLAGS_INLINE_VALUES);
assert(Py_TYPE(obj)->tp_flags & Py_TPFLAGS_MANAGED_DICT);
- assert(Py_TYPE(obj)->tp_basicsize == sizeof(PyObject));
- return (PyDictValues *)((char *)obj + sizeof(PyObject));
+ return (PyDictValues *)((char *)obj + tp->tp_basicsize);
}
extern PyObject ** _PyObject_ComputedDictPointer(PyObject *);
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2024-08-21-08-53-00.gh-issue-115776.9A7Dv_.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2024-08-21-08-53-00.gh-issue-115776.9A7Dv_.rst
new file mode 100644
index 00000000000000..953ebd72382e1f
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2024-08-21-08-53-00.gh-issue-115776.9A7Dv_.rst
@@ -0,0 +1,2 @@
+Enables inline values (Python's equivalent of hidden classes) on any class
+who's instances are of a fixed size.
diff --git a/Objects/object_layout.md b/Objects/object_layout.md
index 352409425ee802..4a781668636324 100644
--- a/Objects/object_layout.md
+++ b/Objects/object_layout.md
@@ -28,6 +28,10 @@ So the pre-header is these two fields:
If the object has no physical dictionary, then the ``dict_pointer``
is set to `NULL`.
+In 3.13 only objects with no additional data could have inline values.
+That is, instances of classes with `tp_basicsize == sizeof(PyObject)`.
+In 3.14, any object whose class has `tp_itemsize == 0` can have inline values.
+In both versions, the inline values starts `tp_basicsize` bytes after the
object.
<details>
<summary> 3.12 </summary>
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 0d7009ac57bd5f..f74d51222b7a65 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -8340,7 +8340,7 @@ type_ready_managed_dict(PyTypeObject *type)
return -1;
}
}
- if (type->tp_itemsize == 0 && type->tp_basicsize == sizeof(PyObject)) {
+ if (type->tp_itemsize == 0) {
type->tp_flags |= Py_TPFLAGS_INLINE_VALUES;
}
return 0;
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 5adcd77b4d5e6e..250e2d12a9de0b 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -2012,9 +2012,10 @@ dummy_func(
DEOPT_IF(!_PyObject_InlineValues(owner_o)->valid);
}
- split op(_LOAD_ATTR_INSTANCE_VALUE, (index/1, owner -- attr, null if
(oparg & 1))) {
+ split op(_LOAD_ATTR_INSTANCE_VALUE, (offset/1, owner -- attr, null if
(oparg & 1))) {
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
- PyObject *attr_o = _PyObject_InlineValues(owner_o)->values[index];
+ PyObject **value_ptr = (PyObject**)(((char *)owner_o) + offset);
+ PyObject *attr_o = *value_ptr;
DEOPT_IF(attr_o == NULL);
STAT_INC(LOAD_ATTR, hit);
Py_INCREF(attr_o);
@@ -2196,16 +2197,17 @@ dummy_func(
EXIT_IF(_PyObject_InlineValues(owner_o)->valid == 0);
}
- op(_STORE_ATTR_INSTANCE_VALUE, (index/1, value, owner --)) {
+ op(_STORE_ATTR_INSTANCE_VALUE, (offset/1, value, owner --)) {
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
STAT_INC(STORE_ATTR, hit);
assert(_PyObject_GetManagedDict(owner_o) == NULL);
- PyDictValues *values = _PyObject_InlineValues(owner_o);
-
- PyObject *old_value = values->values[index];
- values->values[index] = PyStackRef_AsPyObjectSteal(value);
+ PyObject **value_ptr = (PyObject**)(((char *)owner_o) + offset);
+ PyObject *old_value = *value_ptr;
+ *value_ptr = PyStackRef_AsPyObjectSteal(value);
if (old_value == NULL) {
+ PyDictValues *values = _PyObject_InlineValues(owner_o);
+ int index = value_ptr - values->values;
_PyDictValues_AddToInsertionOrder(values, index);
}
else {
diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index 1db8e5067322ee..55b06a0e235dac 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -2277,9 +2277,10 @@
_PyStackRef null = PyStackRef_NULL;
(void)null;
owner = stack_pointer[-1];
- uint16_t index = (uint16_t)CURRENT_OPERAND();
+ uint16_t offset = (uint16_t)CURRENT_OPERAND();
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
- PyObject *attr_o = _PyObject_InlineValues(owner_o)->values[index];
+ PyObject **value_ptr = (PyObject**)(((char *)owner_o) + offset);
+ PyObject *attr_o = *value_ptr;
if (attr_o == NULL) {
UOP_STAT_INC(uopcode, miss);
JUMP_TO_JUMP_TARGET();
@@ -2299,9 +2300,10 @@
_PyStackRef null = PyStackRef_NULL;
(void)null;
owner = stack_pointer[-1];
- uint16_t index = (uint16_t)CURRENT_OPERAND();
+ uint16_t offset = (uint16_t)CURRENT_OPERAND();
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
- PyObject *attr_o = _PyObject_InlineValues(owner_o)->values[index];
+ PyObject **value_ptr = (PyObject**)(((char *)owner_o) + offset);
+ PyObject *attr_o = *value_ptr;
if (attr_o == NULL) {
UOP_STAT_INC(uopcode, miss);
JUMP_TO_JUMP_TARGET();
@@ -2583,14 +2585,16 @@
_PyStackRef value;
owner = stack_pointer[-1];
value = stack_pointer[-2];
- uint16_t index = (uint16_t)CURRENT_OPERAND();
+ uint16_t offset = (uint16_t)CURRENT_OPERAND();
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
STAT_INC(STORE_ATTR, hit);
assert(_PyObject_GetManagedDict(owner_o) == NULL);
- PyDictValues *values = _PyObject_InlineValues(owner_o);
- PyObject *old_value = values->values[index];
- values->values[index] = PyStackRef_AsPyObjectSteal(value);
+ PyObject **value_ptr = (PyObject**)(((char *)owner_o) + offset);
+ PyObject *old_value = *value_ptr;
+ *value_ptr = PyStackRef_AsPyObjectSteal(value);
if (old_value == NULL) {
+ PyDictValues *values = _PyObject_InlineValues(owner_o);
+ int index = value_ptr - values->values;
_PyDictValues_AddToInsertionOrder(values, index);
}
else {
diff --git a/Python/gc.c b/Python/gc.c
index 923a79299cab03..f920743b9213de 100644
--- a/Python/gc.c
+++ b/Python/gc.c
@@ -2055,6 +2055,9 @@ _PyObject_GC_New(PyTypeObject *tp)
return NULL;
}
_PyObject_Init(op, tp);
+ if (tp->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
+ _PyObject_InitInlineValues(op, tp);
+ }
return op;
}
diff --git a/Python/gc_free_threading.c b/Python/gc_free_threading.c
index b95456519dca06..54de0c2671ae68 100644
--- a/Python/gc_free_threading.c
+++ b/Python/gc_free_threading.c
@@ -1810,6 +1810,9 @@ _PyObject_GC_New(PyTypeObject *tp)
return NULL;
}
_PyObject_Init(op, tp);
+ if (tp->tp_flags & Py_TPFLAGS_INLINE_VALUES) {
+ _PyObject_InitInlineValues(op, tp);
+ }
return op;
}
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 42a58bb7285d21..13bbff29d09133 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -4999,9 +4999,10 @@
}
// _LOAD_ATTR_INSTANCE_VALUE
{
- uint16_t index = read_u16(&this_instr[4].cache);
+ uint16_t offset = read_u16(&this_instr[4].cache);
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
- PyObject *attr_o =
_PyObject_InlineValues(owner_o)->values[index];
+ PyObject **value_ptr = (PyObject**)(((char *)owner_o) +
offset);
+ PyObject *attr_o = *value_ptr;
DEOPT_IF(attr_o == NULL, LOAD_ATTR);
STAT_INC(LOAD_ATTR, hit);
Py_INCREF(attr_o);
@@ -6829,14 +6830,16 @@
// _STORE_ATTR_INSTANCE_VALUE
value = stack_pointer[-2];
{
- uint16_t index = read_u16(&this_instr[4].cache);
+ uint16_t offset = read_u16(&this_instr[4].cache);
PyObject *owner_o = PyStackRef_AsPyObjectBorrow(owner);
STAT_INC(STORE_ATTR, hit);
assert(_PyObject_GetManagedDict(owner_o) == NULL);
- PyDictValues *values = _PyObject_InlineValues(owner_o);
- PyObject *old_value = values->values[index];
- values->values[index] = PyStackRef_AsPyObjectSteal(value);
+ PyObject **value_ptr = (PyObject**)(((char *)owner_o) +
offset);
+ PyObject *old_value = *value_ptr;
+ *value_ptr = PyStackRef_AsPyObjectSteal(value);
if (old_value == NULL) {
+ PyDictValues *values = _PyObject_InlineValues(owner_o);
+ int index = value_ptr - values->values;
_PyDictValues_AddToInsertionOrder(values, index);
}
else {
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index 6e46d9bed11fbc..9a1b9da52f4bb5 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -452,10 +452,10 @@ dummy_func(void) {
top, unused[oparg-2], bottom)) {
}
- op(_LOAD_ATTR_INSTANCE_VALUE, (index/1, owner -- attr, null if (oparg &
1))) {
+ op(_LOAD_ATTR_INSTANCE_VALUE, (offset/1, owner -- attr, null if (oparg &
1))) {
attr = sym_new_not_null(ctx);
null = sym_new_null(ctx);
- (void)index;
+ (void)offset;
(void)owner;
}
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index e5be9d0e3b5ee7..672fec3946f2fb 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -1064,10 +1064,10 @@
_Py_UopsSymbol *attr;
_Py_UopsSymbol *null = NULL;
owner = stack_pointer[-1];
- uint16_t index = (uint16_t)this_instr->operand;
+ uint16_t offset = (uint16_t)this_instr->operand;
attr = sym_new_not_null(ctx);
null = sym_new_null(ctx);
- (void)index;
+ (void)offset;
(void)owner;
stack_pointer[-1] = attr;
if (oparg & 1) stack_pointer[0] = null;
diff --git a/Python/specialize.c b/Python/specialize.c
index b3a2e07c3bbcb8..db794bea0bee29 100644
--- a/Python/specialize.c
+++ b/Python/specialize.c
@@ -849,15 +849,19 @@ specialize_dict_access(
assert(PyUnicode_CheckExact(name));
Py_ssize_t index = _PyDictKeys_StringLookup(keys, name);
assert (index != DKIX_ERROR);
- if (index != (uint16_t)index) {
- SPECIALIZATION_FAIL(base_op,
- index == DKIX_EMPTY ?
- SPEC_FAIL_ATTR_NOT_IN_KEYS :
- SPEC_FAIL_OUT_OF_RANGE);
+ if (index == DKIX_EMPTY) {
+ SPECIALIZATION_FAIL(base_op, SPEC_FAIL_ATTR_NOT_IN_KEYS);
+ return 0;
+ }
+ assert(index >= 0);
+ char *value_addr = (char
*)&_PyObject_InlineValues(owner)->values[index];
+ Py_ssize_t offset = value_addr - (char *)owner;
+ if (offset != (uint16_t)offset) {
+ SPECIALIZATION_FAIL(base_op, SPEC_FAIL_OUT_OF_RANGE);
return 0;
}
write_u32(cache->version, type->tp_version_tag);
- cache->index = (uint16_t)index;
+ cache->index = (uint16_t)offset;
instr->op.code = values_op;
}
else {
diff --git a/Tools/gdb/libpython.py b/Tools/gdb/libpython.py
index 8aa74635aedb4f..cf03788d037a81 100755
--- a/Tools/gdb/libpython.py
+++ b/Tools/gdb/libpython.py
@@ -69,9 +69,6 @@ def _type_unsigned_int_ptr():
def _sizeof_void_p():
return gdb.lookup_type('void').pointer().sizeof
-def _sizeof_pyobject():
- return gdb.lookup_type('PyObject').sizeof
-
def _managed_dict_offset():
# See pycore_object.h
pyobj = gdb.lookup_type("PyObject")
@@ -505,7 +502,7 @@ def get_keys_values(self):
dict_ptr = dict_ptr_ptr.cast(_type_char_ptr().pointer()).dereference()
if int(dict_ptr):
return None
- char_ptr = obj_ptr + _sizeof_pyobject()
+ char_ptr = obj_ptr + typeobj.field('tp_basicsize')
values_ptr = char_ptr.cast(gdb.lookup_type("PyDictValues").pointer())
values = values_ptr['values']
return PyKeysValuesPair(self.get_cached_keys(), values)
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