mirror of https://github.com/python/cpython.git
71 lines
2.6 KiB
C
71 lines
2.6 KiB
C
#ifndef Py_EMSCRIPTEN_TRAMPOLINE_H
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#define Py_EMSCRIPTEN_TRAMPOLINE_H
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#include "pycore_typedefs.h" // _PyRuntimeState
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/**
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* C function call trampolines to mitigate bad function pointer casts.
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*
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* Section 6.3.2.3, paragraph 8 reads:
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*
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* A pointer to a function of one type may be converted to a pointer to a
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* function of another type and back again; the result shall compare equal to
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* the original pointer. If a converted pointer is used to call a function
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* whose type is not compatible with the pointed-to type, the behavior is
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* undefined.
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*
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* Typical native ABIs ignore additional arguments or fill in missing values
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* with 0/NULL in function pointer cast. Compilers do not show warnings when a
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* function pointer is explicitly casted to an incompatible type.
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*
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* Bad fpcasts are an issue in WebAssembly. WASM's indirect_call has strict
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* function signature checks. Argument count, types, and return type must match.
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*
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* Third party code unintentionally rely on problematic fpcasts. The call
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* trampoline mitigates common occurrences of bad fpcasts on Emscripten.
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*/
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#if defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
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void
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_Py_EmscriptenTrampoline_Init(_PyRuntimeState *runtime);
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PyObject*
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_PyEM_TrampolineCall(PyCFunctionWithKeywords func,
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PyObject* self,
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PyObject* args,
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PyObject* kw);
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#define _PyCFunction_TrampolineCall(meth, self, args) \
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_PyEM_TrampolineCall(*_PyCFunctionWithKeywords_CAST(meth), (self), (args), NULL)
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#define _PyCFunctionWithKeywords_TrampolineCall(meth, self, args, kw) \
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_PyEM_TrampolineCall((meth), (self), (args), (kw))
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#define descr_set_trampoline_call(set, obj, value, closure) \
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((int)_PyEM_TrampolineCall(_PyCFunctionWithKeywords_CAST(set), (obj), \
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(value), (PyObject*)(closure)))
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#define descr_get_trampoline_call(get, obj, closure) \
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_PyEM_TrampolineCall(_PyCFunctionWithKeywords_CAST(get), (obj), \
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(PyObject*)(closure), NULL)
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#else // defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
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#define _PyCFunction_TrampolineCall(meth, self, args) \
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(meth)((self), (args))
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#define _PyCFunctionWithKeywords_TrampolineCall(meth, self, args, kw) \
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(meth)((self), (args), (kw))
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#define descr_set_trampoline_call(set, obj, value, closure) \
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(set)((obj), (value), (closure))
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#define descr_get_trampoline_call(get, obj, closure) \
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(get)((obj), (closure))
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#endif // defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
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#endif // ndef Py_EMSCRIPTEN_SIGNAL_H
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