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GH-141794: Limit size of generated machine code. #142228

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Merged
markshannon merged 2 commits into from
Dec 3, 2025
Merged

GH-141794: Limit size of generated machine code. #142228

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d1d89f2
Limit size of generated machine code.
markshannon Nov 20, 2025
4d0725a
Update Python/ceval.c
markshannon Dec 3, 2025
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58 changes: 58 additions & 0 deletions Include/internal/pycore_ceval.h
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Original file line number Diff line number Diff line change
Expand Up @@ -410,6 +410,64 @@ _PyForIter_VirtualIteratorNext(PyThreadState* tstate, struct _PyInterpreterFrame

PyAPI_DATA(const _Py_CODEUNIT *) _Py_INTERPRETER_TRAMPOLINE_INSTRUCTIONS_PTR;

/* Helper functions for large uops */

PyAPI_FUNC(PyObject *)
_Py_VectorCall_StackRefSteal(
_PyStackRef callable,
_PyStackRef *arguments,
int total_args,
_PyStackRef kwnames);

PyAPI_FUNC(PyObject *)
_Py_BuiltinCallFast_StackRefSteal(
_PyStackRef callable,
_PyStackRef *arguments,
int total_args);

PyAPI_FUNC(PyObject *)
_Py_BuiltinCallFastWithKeywords_StackRefSteal(
_PyStackRef callable,
_PyStackRef *arguments,
int total_args);

PyAPI_FUNC(PyObject *)
_PyCallMethodDescriptorFast_StackRefSteal(
_PyStackRef callable,
PyMethodDef *meth,
PyObject *self,
_PyStackRef *arguments,
int total_args);

PyAPI_FUNC(PyObject *)
_PyCallMethodDescriptorFastWithKeywords_StackRefSteal(
_PyStackRef callable,
PyMethodDef *meth,
PyObject *self,
_PyStackRef *arguments,
int total_args);

PyAPI_FUNC(PyObject *)
_Py_CallBuiltinClass_StackRefSteal(
_PyStackRef callable,
_PyStackRef *arguments,
int total_args);

PyAPI_FUNC(PyObject *)
_Py_BuildString_StackRefSteal(
_PyStackRef *arguments,
int total_args);

PyAPI_FUNC(PyObject *)
_Py_BuildMap_StackRefSteal(
_PyStackRef *arguments,
int half_args);

PyAPI_FUNC(void)
_Py_assert_within_stack_bounds(
_PyInterpreterFrame *frame, _PyStackRef *stack_pointer,
const char *filename, int lineno);

#ifdef __cplusplus
}
#endif
Expand Down
3 changes: 3 additions & 0 deletions Include/internal/pycore_jit.h
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,9 @@ extern "C" {
# error "this header requires Py_BUILD_CORE define"
#endif

/* To be able to reason about code layout and branches, keep code size below 1 MB */
#define PY_MAX_JIT_CODE_SIZE ((1 << 20)-1)

#ifdef _Py_JIT

typedef _Py_CODEUNIT *(*jit_func)(_PyInterpreterFrame *frame, _PyStackRef *stack_pointer, PyThreadState *tstate);
Expand Down
5 changes: 5 additions & 0 deletions Include/internal/pycore_uop.h
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,12 @@ typedef struct _PyUOpInstruction{
} _PyUOpInstruction;

// This is the length of the trace we translate initially.
#ifdef Py_DEBUG
// With asserts, the stencils are a lot larger
#define UOP_MAX_TRACE_LENGTH 1000
#else
#define UOP_MAX_TRACE_LENGTH 3000
#endif
#define UOP_BUFFER_SIZE (UOP_MAX_TRACE_LENGTH * sizeof(_PyUOpInstruction))

/* Bloom filter with m = 256
Expand Down
54 changes: 27 additions & 27 deletions Lib/test/test_generated_cases.py
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Original file line number Diff line number Diff line change
Expand Up @@ -165,7 +165,7 @@ def test_inst_one_pop(self):
value = stack_pointer[-1];
SPAM(value);
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand All @@ -190,7 +190,7 @@ def test_inst_one_push(self):
res = SPAM();
stack_pointer[0] = res;
stack_pointer += 1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -247,7 +247,7 @@ def test_binary_op(self):
res = SPAM(left, right);
stack_pointer[-2] = res;
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -366,14 +366,14 @@ def test_sync_sp(self):
_PyStackRef res;
arg = stack_pointer[-1];
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
_PyFrame_SetStackPointer(frame, stack_pointer);
escaping_call();
stack_pointer = _PyFrame_GetStackPointer(frame);
res = Py_None;
stack_pointer[0] = res;
stack_pointer += 1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}

Expand Down Expand Up @@ -489,7 +489,7 @@ def test_error_if_pop(self):
res = 0;
stack_pointer[-2] = res;
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -523,7 +523,7 @@ def test_error_if_pop_with_result(self):
}
stack_pointer[-2] = res;
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -553,7 +553,7 @@ def test_cache_effect(self):
uint32_t extra = read_u32(&this_instr[2].cache);
(void)extra;
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -640,7 +640,7 @@ def test_macro_instruction(self):
}
stack_pointer[-3] = res;
stack_pointer += -2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}

Expand Down Expand Up @@ -688,7 +688,7 @@ def test_macro_instruction(self):
stack_pointer = _PyFrame_GetStackPointer(frame);
stack_pointer[-3] = res;
stack_pointer += -2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -827,7 +827,7 @@ def test_array_input(self):
below = stack_pointer[-2 - oparg*2];
SPAM(values, oparg);
stack_pointer += -2 - oparg*2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -860,7 +860,7 @@ def test_array_output(self):
stack_pointer[-2] = below;
stack_pointer[-1 + oparg*3] = above;
stack_pointer += oparg*3;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -889,7 +889,7 @@ def test_array_input_output(self):
above = 0;
stack_pointer[0] = above;
stack_pointer += 1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -918,11 +918,11 @@ def test_array_error_if(self):
extra = stack_pointer[-1 - oparg];
if (oparg == 0) {
stack_pointer += -1 - oparg;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
JUMP_TO_LABEL(error);
}
stack_pointer += -1 - oparg;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -960,7 +960,7 @@ def test_macro_push_push(self):
stack_pointer[0] = val1;
stack_pointer[1] = val2;
stack_pointer += 2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -1263,13 +1263,13 @@ def test_flush(self):
stack_pointer[0] = a;
stack_pointer[1] = b;
stack_pointer += 2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
// SECOND
{
USE(a, b);
}
stack_pointer += -2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -1325,7 +1325,7 @@ def test_pop_on_error_peeks(self):
}
}
stack_pointer += -2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -1368,14 +1368,14 @@ def test_push_then_error(self):
stack_pointer[0] = a;
stack_pointer[1] = b;
stack_pointer += 2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
JUMP_TO_LABEL(error);
}
}
stack_pointer[0] = a;
stack_pointer[1] = b;
stack_pointer += 2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -1661,7 +1661,7 @@ def test_pystackref_frompyobject_new_next_to_cmacro(self):
stack_pointer[0] = out1;
stack_pointer[1] = out2;
stack_pointer += 2;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
DISPATCH();
}
"""
Expand Down Expand Up @@ -1881,7 +1881,7 @@ def test_reassigning_dead_inputs(self):
stack_pointer = _PyFrame_GetStackPointer(frame);
in = temp;
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
_PyFrame_SetStackPointer(frame, stack_pointer);
PyStackRef_CLOSE(in);
stack_pointer = _PyFrame_GetStackPointer(frame);
Expand Down Expand Up @@ -2116,7 +2116,7 @@ def test_validate_uop_unused_input(self):
output = """
case OP: {
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
break;
}
"""
Expand All @@ -2133,7 +2133,7 @@ def test_validate_uop_unused_input(self):
output = """
case OP: {
stack_pointer += -1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
break;
}
"""
Expand All @@ -2155,7 +2155,7 @@ def test_validate_uop_unused_output(self):
foo = NULL;
stack_pointer[0] = foo;
stack_pointer += 1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
break;
}
"""
Expand All @@ -2173,7 +2173,7 @@ def test_validate_uop_unused_output(self):
output = """
case OP: {
stack_pointer += 1;
assert(WITHIN_STACK_BOUNDS());
ASSERT_WITHIN_STACK_BOUNDS(__FILE__, __LINE__);
break;
}
"""
Expand Down
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