https://github.com/python/cpython/commit/0cb52220790d8bc70ec325fd89d52b5f3b7ad29c
commit: 0cb52220790d8bc70ec325fd89d52b5f3b7ad29c
branch: main
author: Neil Schemenauer <nas-git...@arctrix.com>
committer: nascheme <nas-git...@arctrix.com>
date: 2024-12-03T09:32:26-08:00
summary:
gh-115999: Specialize `LOAD_SUPER_ATTR` in free-threaded builds (gh-127128)
Use existing helpers to atomically modify the bytecode. Add unit tests
to ensure specializing is happening as expected. Add test_specialize.py
that can be used with ThreadSanitizer to detect data races.
Fix thread safety issue with cell_set_contents().
files:
M Lib/test/test_opcache.py
M Objects/cellobject.c
M Python/bytecodes.c
M Python/ceval.c
M Python/generated_cases.c.h
M Python/specialize.c
diff --git a/Lib/test/test_opcache.py b/Lib/test/test_opcache.py
index b989b21cd9b3a9..527114445ac13b 100644
--- a/Lib/test/test_opcache.py
+++ b/Lib/test/test_opcache.py
@@ -1249,6 +1249,45 @@ def binary_op_add_unicode():
self.assert_specialized(binary_op_add_unicode, "BINARY_OP_ADD_UNICODE")
self.assert_no_opcode(binary_op_add_unicode, "BINARY_OP")
+ @cpython_only
+ @requires_specialization_ft
+ def test_load_super_attr(self):
+ """Ensure that LOAD_SUPER_ATTR is specialized as expected."""
+
+ class A:
+ def __init__(self):
+ meth = super().__init__
+ super().__init__()
+
+ for _ in range(100):
+ A()
+
+ self.assert_specialized(A.__init__, "LOAD_SUPER_ATTR_ATTR")
+ self.assert_specialized(A.__init__, "LOAD_SUPER_ATTR_METHOD")
+ self.assert_no_opcode(A.__init__, "LOAD_SUPER_ATTR")
+
+ # Temporarily replace super() with something else.
+ real_super = super
+
+ def fake_super():
+ def init(self):
+ pass
+
+ return init
+
+ # Force unspecialize
+ globals()['super'] = fake_super
+ try:
+ # Should be unspecialized after enough calls.
+ for _ in range(100):
+ A()
+ finally:
+ globals()['super'] = real_super
+
+ # Ensure the specialized instructions are not present
+ self.assert_no_opcode(A.__init__, "LOAD_SUPER_ATTR_ATTR")
+ self.assert_no_opcode(A.__init__, "LOAD_SUPER_ATTR_METHOD")
+
@cpython_only
@requires_specialization_ft
def test_contain_op(self):
diff --git a/Objects/cellobject.c b/Objects/cellobject.c
index 590c8a80857699..4ab9083af5e300 100644
--- a/Objects/cellobject.c
+++ b/Objects/cellobject.c
@@ -145,8 +145,9 @@ cell_get_contents(PyObject *self, void *closure)
static int
cell_set_contents(PyObject *self, PyObject *obj, void *Py_UNUSED(ignored))
{
- PyCellObject *op = _PyCell_CAST(self);
- Py_XSETREF(op->ob_ref, Py_XNewRef(obj));
+ PyCellObject *cell = _PyCell_CAST(self);
+ Py_XINCREF(obj);
+ PyCell_SetTakeRef((PyCellObject *)cell, obj);
return 0;
}
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index e96674c3502ef1..dd28aae6a3cb61 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -1946,7 +1946,7 @@ dummy_func(
};
specializing op(_SPECIALIZE_LOAD_SUPER_ATTR, (counter/1,
global_super_st, class_st, unused -- global_super_st, class_st, unused)) {
- #if ENABLE_SPECIALIZATION
+ #if ENABLE_SPECIALIZATION_FT
int load_method = oparg & 1;
if (ADAPTIVE_COUNTER_TRIGGERS(counter)) {
next_instr = this_instr;
@@ -1955,7 +1955,7 @@ dummy_func(
}
OPCODE_DEFERRED_INC(LOAD_SUPER_ATTR);
ADVANCE_ADAPTIVE_COUNTER(this_instr[1].counter);
- #endif /* ENABLE_SPECIALIZATION */
+ #endif /* ENABLE_SPECIALIZATION_FT */
}
tier1 op(_LOAD_SUPER_ATTR, (global_super_st, class_st, self_st --
attr, null if (oparg & 1))) {
diff --git a/Python/ceval.c b/Python/ceval.c
index f9514a6bf25c1b..6795a160506231 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -28,7 +28,6 @@
#include "pycore_setobject.h" // _PySet_Update()
#include "pycore_sliceobject.h" // _PyBuildSlice_ConsumeRefs
#include "pycore_tuple.h" // _PyTuple_ITEMS()
-#include "pycore_typeobject.h" // _PySuper_Lookup()
#include "pycore_uop_ids.h" // Uops
#include "pycore_pyerrors.h"
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index e1f951558de7da..c31601f6d82b77 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -6330,7 +6330,7 @@
global_super_st = stack_pointer[-3];
uint16_t counter = read_u16(&this_instr[1].cache);
(void)counter;
- #if ENABLE_SPECIALIZATION
+ #if ENABLE_SPECIALIZATION_FT
int load_method = oparg & 1;
if (ADAPTIVE_COUNTER_TRIGGERS(counter)) {
next_instr = this_instr;
@@ -6341,7 +6341,7 @@
}
OPCODE_DEFERRED_INC(LOAD_SUPER_ATTR);
ADVANCE_ADAPTIVE_COUNTER(this_instr[1].counter);
- #endif /* ENABLE_SPECIALIZATION */
+ #endif /* ENABLE_SPECIALIZATION_FT */
}
// _LOAD_SUPER_ATTR
{
diff --git a/Python/specialize.c b/Python/specialize.c
index ba13b02a29b133..0fe4e7904de9f8 100644
--- a/Python/specialize.c
+++ b/Python/specialize.c
@@ -794,9 +794,8 @@ _Py_Specialize_LoadSuperAttr(_PyStackRef global_super_st,
_PyStackRef cls_st, _P
PyObject *global_super = PyStackRef_AsPyObjectBorrow(global_super_st);
PyObject *cls = PyStackRef_AsPyObjectBorrow(cls_st);
- assert(ENABLE_SPECIALIZATION);
+ assert(ENABLE_SPECIALIZATION_FT);
assert(_PyOpcode_Caches[LOAD_SUPER_ATTR] ==
INLINE_CACHE_ENTRIES_LOAD_SUPER_ATTR);
- _PySuperAttrCache *cache = (_PySuperAttrCache *)(instr + 1);
if (global_super != (PyObject *)&PySuper_Type) {
SPECIALIZATION_FAIL(LOAD_SUPER_ATTR, SPEC_FAIL_SUPER_SHADOWED);
goto fail;
@@ -805,19 +804,11 @@ _Py_Specialize_LoadSuperAttr(_PyStackRef global_super_st,
_PyStackRef cls_st, _P
SPECIALIZATION_FAIL(LOAD_SUPER_ATTR, SPEC_FAIL_SUPER_BAD_CLASS);
goto fail;
}
- instr->op.code = load_method ? LOAD_SUPER_ATTR_METHOD :
LOAD_SUPER_ATTR_ATTR;
- goto success;
-
-fail:
- STAT_INC(LOAD_SUPER_ATTR, failure);
- assert(!PyErr_Occurred());
- instr->op.code = LOAD_SUPER_ATTR;
- cache->counter = adaptive_counter_backoff(cache->counter);
+ uint8_t load_code = load_method ? LOAD_SUPER_ATTR_METHOD :
LOAD_SUPER_ATTR_ATTR;
+ specialize(instr, load_code);
return;
-success:
- STAT_INC(LOAD_SUPER_ATTR, success);
- assert(!PyErr_Occurred());
- cache->counter = adaptive_counter_cooldown();
+fail:
+ unspecialize(instr);
}
typedef enum {
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