1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
|
#ifndef Py_EMSCRIPTEN_TRAMPOLINE_H
#define Py_EMSCRIPTEN_TRAMPOLINE_H
#include "pycore_runtime.h" // _PyRuntimeState
/**
* C function call trampolines to mitigate bad function pointer casts.
*
* Section 6.3.2.3, paragraph 8 reads:
*
* A pointer to a function of one type may be converted to a pointer to a
* function of another type and back again; the result shall compare equal to
* the original pointer. If a converted pointer is used to call a function
* whose type is not compatible with the pointed-to type, the behavior is
* undefined.
*
* Typical native ABIs ignore additional arguments or fill in missing values
* with 0/NULL in function pointer cast. Compilers do not show warnings when a
* function pointer is explicitly casted to an incompatible type.
*
* Bad fpcasts are an issue in WebAssembly. WASM's indirect_call has strict
* function signature checks. Argument count, types, and return type must match.
*
* Third party code unintentionally rely on problematic fpcasts. The call
* trampoline mitigates common occurrences of bad fpcasts on Emscripten.
*/
#if defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
void _Py_EmscriptenTrampoline_Init(_PyRuntimeState *runtime);
PyObject*
_PyEM_TrampolineCall_JavaScript(PyCFunctionWithKeywords func,
PyObject* self,
PyObject* args,
PyObject* kw);
PyObject*
_PyEM_TrampolineCall_Reflection(PyCFunctionWithKeywords func,
PyObject* self,
PyObject* args,
PyObject* kw);
#define _PyEM_TrampolineCall(meth, self, args, kw) \
((_PyRuntime.wasm_type_reflection_available) ? \
(_PyEM_TrampolineCall_Reflection((PyCFunctionWithKeywords)(meth), (self), (args), (kw))) : \
(_PyEM_TrampolineCall_JavaScript((PyCFunctionWithKeywords)(meth), (self), (args), (kw))))
#define _PyCFunction_TrampolineCall(meth, self, args) \
_PyEM_TrampolineCall( \
(*(PyCFunctionWithKeywords)(void(*)(void))(meth)), (self), (args), NULL)
#define _PyCFunctionWithKeywords_TrampolineCall(meth, self, args, kw) \
_PyEM_TrampolineCall((meth), (self), (args), (kw))
#define descr_set_trampoline_call(set, obj, value, closure) \
((int)_PyEM_TrampolineCall((PyCFunctionWithKeywords)(set), (obj), (value), (PyObject*)(closure)))
#define descr_get_trampoline_call(get, obj, closure) \
_PyEM_TrampolineCall((PyCFunctionWithKeywords)(get), (obj), (PyObject*)(closure), NULL)
#else // defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
#define _Py_EmscriptenTrampoline_Init(runtime)
#define _PyCFunction_TrampolineCall(meth, self, args) \
(meth)((self), (args))
#define _PyCFunctionWithKeywords_TrampolineCall(meth, self, args, kw) \
(meth)((self), (args), (kw))
#define descr_set_trampoline_call(set, obj, value, closure) \
(set)((obj), (value), (closure))
#define descr_get_trampoline_call(get, obj, closure) \
(get)((obj), (closure))
#endif // defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
#endif // ndef Py_EMSCRIPTEN_SIGNAL_H
|
