gh-84461: Fix ctypes and test_ctypes on Emscripten (#94142)

- c_longlong and c_longdouble need experimental WASM bigint.
- Skip tests that need threading
- Define ``CTYPES_MAX_ARGCOUNT`` for Emscripten. libffi-emscripten 2022-06-23 supports up to 1000 args.

Lib/test/test_code.py

@@ -141,6 +141,7 @@ from test.support import (cpython_only,
                           check_impl_detail, requires_debug_ranges,
                           gc_collect)
 from test.support.script_helper import assert_python_ok
+from test.support import threading_helper
 from opcode import opmap
 COPY_FREE_VARS = opmap['COPY_FREE_VARS']
 
@@ -723,6 +724,7 @@ if check_impl_detail(cpython=True) and ctypes is not None:
             self.assertEqual(extra.value, 300)
             del f
 
+        @threading_helper.requires_working_threading()
         def test_free_different_thread(self):
             # Freeing a code object on a different thread then
             # where the co_extra was set should be safe.

Lib/test/test_ctypes/test_as_parameter.py

@@ -122,6 +122,7 @@ class BasicWrapTestCase(unittest.TestCase):
         result = f(self.wrap(-10), self.wrap(cb))
         self.assertEqual(result, -18)
 
+    @need_symbol('c_longlong')
     def test_longlong_callbacks(self):
 
         f = dll._testfunc_callback_q_qf

Lib/test/test_ctypes/test_callbacks.py

@@ -65,10 +65,12 @@ class Callbacks(unittest.TestCase):
     def test_ulong(self):
         self.check_type(c_ulong, 42)
 
+    @need_symbol('c_longlong')
     def test_longlong(self):
         self.check_type(c_longlong, 42)
         self.check_type(c_longlong, -42)
 
+    @need_symbol('c_ulonglong')
     def test_ulonglong(self):
         self.check_type(c_ulonglong, 42)
 
@@ -82,6 +84,7 @@ class Callbacks(unittest.TestCase):
         self.check_type(c_double, 3.14)
         self.check_type(c_double, -3.14)
 
+    @need_symbol('c_longdouble')
     def test_longdouble(self):
         self.check_type(c_longdouble, 3.14)
         self.check_type(c_longdouble, -3.14)

Lib/test/test_ctypes/test_cfuncs.py

@@ -111,24 +111,28 @@ class CFunctions(unittest.TestCase):
         self.assertEqual(self._dll.tf_bL(b' ', 4294967295), 1431655765)
         self.assertEqual(self.U(), 4294967295)
 
+    @need_symbol('c_longlong')
     def test_longlong(self):
         self._dll.tf_q.restype = c_longlong
         self._dll.tf_q.argtypes = (c_longlong, )
         self.assertEqual(self._dll.tf_q(-9223372036854775806), -3074457345618258602)
         self.assertEqual(self.S(), -9223372036854775806)
 
+    @need_symbol('c_longlong')
     def test_longlong_plus(self):
         self._dll.tf_bq.restype = c_longlong
         self._dll.tf_bq.argtypes = (c_byte, c_longlong)
         self.assertEqual(self._dll.tf_bq(0, -9223372036854775806), -3074457345618258602)
         self.assertEqual(self.S(), -9223372036854775806)
 
+    @need_symbol('c_ulonglong')
     def test_ulonglong(self):
         self._dll.tf_Q.restype = c_ulonglong
         self._dll.tf_Q.argtypes = (c_ulonglong, )
         self.assertEqual(self._dll.tf_Q(18446744073709551615), 6148914691236517205)
         self.assertEqual(self.U(), 18446744073709551615)
 
+    @need_symbol('c_ulonglong')
     def test_ulonglong_plus(self):
         self._dll.tf_bQ.restype = c_ulonglong
         self._dll.tf_bQ.argtypes = (c_byte, c_ulonglong)
@@ -159,12 +163,14 @@ class CFunctions(unittest.TestCase):
         self.assertEqual(self._dll.tf_bd(0, 42.), 14.)
         self.assertEqual(self.S(), 42)
 
+    @need_symbol('c_longdouble')
     def test_longdouble(self):
         self._dll.tf_D.restype = c_longdouble
         self._dll.tf_D.argtypes = (c_longdouble,)
         self.assertEqual(self._dll.tf_D(42.), 14.)
         self.assertEqual(self.S(), 42)
 
+    @need_symbol('c_longdouble')
     def test_longdouble_plus(self):
         self._dll.tf_bD.restype = c_longdouble
         self._dll.tf_bD.argtypes = (c_byte, c_longdouble)

Lib/test/test_ctypes/test_functions.py

@@ -128,6 +128,7 @@ class FunctionTestCase(unittest.TestCase):
         self.assertEqual(result, -21)
         self.assertEqual(type(result), float)
 
+    @need_symbol('c_longdouble')
     def test_longdoubleresult(self):
         f = dll._testfunc_D_bhilfD
         f.argtypes = [c_byte, c_short, c_int, c_long, c_float, c_longdouble]

Modules/_ctypes/ctypes.h

@@ -19,7 +19,11 @@
  * to avoid allocating a massive buffer on the stack.
  */
 #ifndef CTYPES_MAX_ARGCOUNT
-  #define CTYPES_MAX_ARGCOUNT 1024
+  #ifdef __EMSCRIPTEN__
+    #define CTYPES_MAX_ARGCOUNT 1000
+  #else
+    #define CTYPES_MAX_ARGCOUNT 1024
+  #endif
 #endif
 
 typedef struct tagPyCArgObject PyCArgObject;

Tools/wasm/README.md

@@ -173,6 +173,8 @@ functions.
   [bpo-46390](https://bugs.python.org/issue46390).
 - Python's object allocator ``obmalloc`` is disabled by default.
 - ``ensurepip`` is not available.
+- Some ``ctypes`` features like ``c_longlong`` and ``c_longdouble`` may need
+   NodeJS option ``--experimental-wasm-bigint``.
 
 ## wasm32-emscripten in browsers
 

configure

@@ -6775,13 +6775,11 @@ then
   case $ac_sys_system/$ac_sys_emscripten_target in #(
   Emscripten/node*) :
 
+      # bigint for ctypes c_longlong, c_longdouble
+      HOSTRUNNER="node --experimental-wasm-bigint"
       if test "x$enable_wasm_pthreads" = xyes; then :
 
-        HOSTRUNNER='node --experimental-wasm-threads --experimental-wasm-bulk-memory'
+        HOSTRUNNER="$HOSTRUNNER --experimental-wasm-threads --experimental-wasm-bulk-memory"
-
-else
-
-        HOSTRUNNER='node'
 
 fi
      ;; #(

configure.ac

@@ -1486,10 +1486,10 @@ if test -z "$HOSTRUNNER"
 then
   AS_CASE([$ac_sys_system/$ac_sys_emscripten_target],
     [Emscripten/node*], [
+      # bigint for ctypes c_longlong, c_longdouble
+      HOSTRUNNER="node --experimental-wasm-bigint"
       AS_VAR_IF([enable_wasm_pthreads], [yes], [
-        HOSTRUNNER='node --experimental-wasm-threads --experimental-wasm-bulk-memory'
+        HOSTRUNNER="$HOSTRUNNER --experimental-wasm-threads --experimental-wasm-bulk-memory"
-      ], [
-        HOSTRUNNER='node'
       ])
     ],
     dnl TODO: support other WASI runtimes