gh-128627: Emscripten: Use wasm-gc based call adaptor if available (#128628)

Replaces the trampoline mechanism in Emscripten with an implementation that uses a
recently added feature of wasm-gc instead of JS type reflection, when that feature is
available.

2 files changed, 7 insertions, 19 deletions

diff --git a/Include/internal/pycore_emscripten_trampoline.h b/Include/internal/pycore_emscripten_trampoline.h
index e519c99..5546ebb 100644
--- a/Include/internal/pycore_emscripten_trampoline.h
+++ b/Include/internal/pycore_emscripten_trampoline.h
@@ -27,24 +27,14 @@
 
 #if defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
 
-void _Py_EmscriptenTrampoline_Init(_PyRuntimeState *runtime);
+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))))
+_PyEM_TrampolineCall(PyCFunctionWithKeywords func,
+                     PyObject* self,
+                     PyObject* args,
+                     PyObject* kw);
 
 #define _PyCFunction_TrampolineCall(meth, self, args) \
     _PyEM_TrampolineCall( \
@@ -62,8 +52,6 @@ _PyEM_TrampolineCall_Reflection(PyCFunctionWithKeywords func,
 
 #else // defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
 
-#define _Py_EmscriptenTrampoline_Init(runtime)
-
 #define _PyCFunction_TrampolineCall(meth, self, args) \
     (meth)((self), (args))
 
diff --git a/Include/internal/pycore_runtime.h b/Include/internal/pycore_runtime.h
index 86d0245..cf12379 100644
--- a/Include/internal/pycore_runtime.h
+++ b/Include/internal/pycore_runtime.h
@@ -172,7 +172,7 @@ typedef struct pyruntimestate {
 #if defined(__EMSCRIPTEN__) && defined(PY_CALL_TRAMPOLINE)
     // Used in "Python/emscripten_trampoline.c" to choose between type
     // reflection trampoline and EM_JS trampoline.
-    bool wasm_type_reflection_available;
+    int (*emscripten_count_args_function)(PyCFunctionWithKeywords func);
 #endif
 
     /* All the objects that are shared by the runtime's interpreters. */