patch 9.0.1980: win32: issues with stable python ABI

Problem:  win32: issues with stable python ABI
Solution: if_python3,win32: Fix Python3 stable ABI

There were some issues in current stable ABI implementation on Windows:
* Python DLL name should be `python3.dll` instead of `python311.dll` and
  so on. (See: https://docs.python.org/3/c-api/stable.html)
* Some non-stable API functions were used:
  - `_PyObject_NextNotImplemented`
  - `PyStdPrinter_Type`
* `reset_stdin()` and `hook_py_exit()` didn't work with `python3.dll`.
  `python3.dll` is a special type of DLL called forwarder DLL.
  It just forwards the functions to other DLL (e.g. `python311.dll`).
  There were two issues regarding these functions:
  - `python3.dll` doesn't have import tables. This caused a crash in
    `get_imported_func_info()`. Add a check whether the specified DLL
    has an import table.
  - `reset_stdin()` and `hook_py_exit()` should be applied to the
    forwarded DLL (e.g. `python311.dll`), not to `python3.dll`.
    Check the export directory of `python3.dll` to find the forwarded
    DLL and apply the functions to it.

closes: #13260

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Ken Takata <kentkt@csc.jp>

src/Make_cyg_ming.mak

@@ -394,16 +394,21 @@ DYNAMIC_PYTHON3=yes
 
  ifndef PYTHON3_VER
 PYTHON3_VER=36
+ endif
+ ifeq ($(DYNAMIC_PYTHON3_STABLE_ABI),yes)
+PYTHON3_NAME=python3
+ else
+PYTHON3_NAME=python$(PYTHON3_VER)
  endif
  ifndef DYNAMIC_PYTHON3_DLL
-DYNAMIC_PYTHON3_DLL=python$(PYTHON3_VER).dll
+DYNAMIC_PYTHON3_DLL=$(PYTHON3_NAME).dll
  endif
  ifdef PYTHON3_HOME
 PYTHON3_HOME_DEF=-DPYTHON3_HOME=L\"$(PYTHON3_HOME)\"
  endif
 
  ifeq (no,$(DYNAMIC_PYTHON3))
-PYTHON3LIB=-L$(PYTHON3)/libs -lpython$(PYTHON3_VER)
+PYTHON3LIB=-L$(PYTHON3)/libs -l$(PYTHON3_NAME)
  endif
 
  ifndef PYTHON3INC

src/Make_mvc.mak

@@ -937,8 +937,13 @@ PYTHON_LIB = "$(PYTHON)\libs\python$(PYTHON_VER).lib"
 ! ifndef PYTHON3_VER
 PYTHON3_VER = 36
 ! endif
+! if "$(DYNAMIC_PYTHON3_STABLE_ABI)" == "yes"
+PYTHON3_NAME = python3
+! else
+PYTHON3_NAME = python$(PYTHON3_VER)
+! endif
 ! ifndef DYNAMIC_PYTHON3_DLL
-DYNAMIC_PYTHON3_DLL = python$(PYTHON3_VER).dll
+DYNAMIC_PYTHON3_DLL = $(PYTHON3_NAME).dll
 ! endif
 ! message Python3 requested (version $(PYTHON3_VER)) - root dir is "$(PYTHON3)"
 ! if "$(DYNAMIC_PYTHON3)" == "yes"
@@ -953,13 +958,11 @@ CFLAGS = $(CFLAGS) -DDYNAMIC_PYTHON3 \
 !  if "$(DYNAMIC_PYTHON3_STABLE_ABI)" == "yes"
 CFLAGS = $(CFLAGS) -DDYNAMIC_PYTHON3_STABLE_ABI
 PYTHON3_INC = $(PYTHON3_INC) -DPy_LIMITED_API=0x3080000
-PYTHON3_LIB = /nodefaultlib:python3.lib
-!  else
-PYTHON3_LIB = /nodefaultlib:python$(PYTHON3_VER).lib
 !  endif
+PYTHON3_LIB = /nodefaultlib:$(PYTHON3_NAME).lib
 ! else
 CFLAGS = $(CFLAGS) -DPYTHON3_DLL=\"$(DYNAMIC_PYTHON3_DLL)\"
-PYTHON3_LIB = "$(PYTHON3)\libs\python$(PYTHON3_VER).lib"
+PYTHON3_LIB = "$(PYTHON3)\libs\$(PYTHON3_NAME).lib"
 ! endif
 !endif
 

src/if_python3.c

@@ -242,7 +242,7 @@ static HINSTANCE hinstPy3 = 0; // Instance of python.dll
 # if PY_VERSION_HEX >= 0x03040000
 #  define PyType_GetFlags py3_PyType_GetFlags
 # endif
-#undef Py_BuildValue
+# undef Py_BuildValue
 # define Py_BuildValue py3_Py_BuildValue
 # define Py_SetPythonHome py3_Py_SetPythonHome
 # define Py_Initialize py3_Py_Initialize
@@ -251,7 +251,9 @@ static HINSTANCE hinstPy3 = 0; // Instance of python.dll
 # define _Py_NoneStruct (*py3__Py_NoneStruct)
 # define _Py_FalseStruct (*py3__Py_FalseStruct)
 # define _Py_TrueStruct (*py3__Py_TrueStruct)
-# define _PyObject_NextNotImplemented (*py3__PyObject_NextNotImplemented)
+# ifndef USE_LIMITED_API
+#  define _PyObject_NextNotImplemented (*py3__PyObject_NextNotImplemented)
+# endif
 # define PyModule_AddObject py3_PyModule_AddObject
 # define PyImport_AppendInittab py3_PyImport_AppendInittab
 # define PyImport_AddModule py3_PyImport_AddModule
@@ -288,7 +290,9 @@ static HINSTANCE hinstPy3 = 0; // Instance of python.dll
 # define PyFloat_AsDouble py3_PyFloat_AsDouble
 # define PyObject_GenericGetAttr py3_PyObject_GenericGetAttr
 # define PyType_Type (*py3_PyType_Type)
-# define PyStdPrinter_Type (*py3_PyStdPrinter_Type)
+# ifndef USE_LIMITED_API
+#  define PyStdPrinter_Type (*py3_PyStdPrinter_Type)
+# endif
 # define PySlice_Type (*py3_PySlice_Type)
 # define PyFloat_Type (*py3_PyFloat_Type)
 # define PyNumber_Check (*py3_PyNumber_Check)
@@ -449,7 +453,9 @@ static void (*py3_PyErr_Clear)(void);
 static PyObject* (*py3_PyErr_Format)(PyObject *, const char *, ...);
 static void (*py3_PyErr_PrintEx)(int);
 static PyObject*(*py3__PyObject_Init)(PyObject *, PyTypeObject *);
+# ifndef USE_LIMITED_API
 static iternextfunc py3__PyObject_NextNotImplemented;
+# endif
 static PyObject* py3__Py_NoneStruct;
 static PyObject* py3__Py_FalseStruct;
 static PyObject* py3__Py_TrueStruct;
@@ -485,7 +491,9 @@ static PyObject* (*py3_PyObject_GenericGetAttr)(PyObject *obj, PyObject *name);
 static PyObject* (*py3_PyType_GenericAlloc)(PyTypeObject *type, Py_ssize_t nitems);
 static PyObject* (*py3_PyType_GenericNew)(PyTypeObject *type, PyObject *args, PyObject *kwds);
 static PyTypeObject* py3_PyType_Type;
+# ifndef USE_LIMITED_API
 static PyTypeObject* py3_PyStdPrinter_Type;
+# endif
 static PyTypeObject* py3_PySlice_Type;
 static PyTypeObject* py3_PyFloat_Type;
 PyTypeObject* py3_PyBool_Type;
@@ -633,7 +641,9 @@ static struct
     {"PyEval_SaveThread", (PYTHON_PROC*)&py3_PyEval_SaveThread},
     {"_PyArg_Parse_SizeT", (PYTHON_PROC*)&py3_PyArg_Parse},
     {"Py_IsInitialized", (PYTHON_PROC*)&py3_Py_IsInitialized},
+# ifndef USE_LIMITED_API
     {"_PyObject_NextNotImplemented", (PYTHON_PROC*)&py3__PyObject_NextNotImplemented},
+# endif
     {"_Py_NoneStruct", (PYTHON_PROC*)&py3__Py_NoneStruct},
     {"_Py_FalseStruct", (PYTHON_PROC*)&py3__Py_FalseStruct},
     {"_Py_TrueStruct", (PYTHON_PROC*)&py3__Py_TrueStruct},
@@ -681,7 +691,9 @@ static struct
     {"PyType_GenericAlloc", (PYTHON_PROC*)&py3_PyType_GenericAlloc},
     {"PyType_GenericNew", (PYTHON_PROC*)&py3_PyType_GenericNew},
     {"PyType_Type", (PYTHON_PROC*)&py3_PyType_Type},
+# ifndef USE_LIMITED_API
     {"PyStdPrinter_Type", (PYTHON_PROC*)&py3_PyStdPrinter_Type},
+# endif
     {"PySlice_Type", (PYTHON_PROC*)&py3_PySlice_Type},
     {"PyFloat_Type", (PYTHON_PROC*)&py3_PyFloat_Type},
 # if PY_VERSION_HEX < 0x030c00b0
@@ -1167,7 +1179,7 @@ reset_stdin(void)
 {
     FILE *(*py__acrt_iob_func)(unsigned) = NULL;
     FILE *(*pyfreopen)(const char *, const char *, FILE *) = NULL;
-    HINSTANCE hinst = hinstPy3;
+    HINSTANCE hinst = get_forwarded_dll(hinstPy3);
 
     if (hinst == NULL || is_stdin_readable())
 	return;
@@ -1219,7 +1231,7 @@ hooked_exit(int ret)
     static void
 hook_py_exit(void)
 {
-    HINSTANCE hinst = hinstPy3;
+    HINSTANCE hinst = get_forwarded_dll(hinstPy3);
 
     if (hinst == NULL || orig_exit != NULL)
 	return;

src/os_win32.c

@@ -626,15 +626,20 @@ get_imported_func_info(HINSTANCE hInst, const char *funcname, int info,
     PIMAGE_THUNK_DATA		pIAT;	    // Import Address Table
     PIMAGE_THUNK_DATA		pINT;	    // Import Name Table
     PIMAGE_IMPORT_BY_NAME	pImpName;
+    DWORD			ImpVA;
 
     if (pDOS->e_magic != IMAGE_DOS_SIGNATURE)
 	return NULL;
     pPE = (PIMAGE_NT_HEADERS)(pImage + pDOS->e_lfanew);
     if (pPE->Signature != IMAGE_NT_SIGNATURE)
 	return NULL;
-    pImpDesc = (PIMAGE_IMPORT_DESCRIPTOR)(pImage
+
-	    + pPE->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT]
+    ImpVA = pPE->OptionalHeader
-							    .VirtualAddress);
+		.DataDirectory[IMAGE_DIRECTORY_ENTRY_IMPORT].VirtualAddress;
+    if (ImpVA == 0)
+	return NULL;	// No Import Table
+    pImpDesc = (PIMAGE_IMPORT_DESCRIPTOR)(pImage + ImpVA);
+
     for (; pImpDesc->FirstThunk; ++pImpDesc)
     {
 	if (!pImpDesc->OriginalFirstThunk)
@@ -709,6 +714,65 @@ hook_dll_import_func(HINSTANCE hInst, const char *funcname, const void *hook)
 }
 #endif
 
+#if defined(FEAT_PYTHON3) || defined(PROTO)
+/*
+ * Check if the specified DLL is a function forwarder.
+ * If yes, return the instance of the forwarded DLL.
+ * If no, return the specified DLL.
+ * If error, return NULL.
+ * This assumes that the DLL forwards all the function to a single DLL.
+ */
+    HINSTANCE
+get_forwarded_dll(HINSTANCE hInst)
+{
+    PBYTE			pImage = (PBYTE)hInst;
+    PIMAGE_DOS_HEADER		pDOS = (PIMAGE_DOS_HEADER)hInst;
+    PIMAGE_NT_HEADERS		pPE;
+    PIMAGE_EXPORT_DIRECTORY	pExpDir;
+    DWORD			ExpVA;
+    DWORD			ExpSize;
+    LPDWORD			pFunctionTable;
+
+    if (pDOS->e_magic != IMAGE_DOS_SIGNATURE)
+	return NULL;
+    pPE = (PIMAGE_NT_HEADERS)(pImage + pDOS->e_lfanew);
+    if (pPE->Signature != IMAGE_NT_SIGNATURE)
+	return NULL;
+
+    ExpVA = pPE->OptionalHeader
+		.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].VirtualAddress;
+    ExpSize = pPE->OptionalHeader
+		.DataDirectory[IMAGE_DIRECTORY_ENTRY_EXPORT].Size;
+    if (ExpVA == 0)
+	return hInst;	// No Export Directory
+    pExpDir = (PIMAGE_EXPORT_DIRECTORY)(pImage + ExpVA);
+    pFunctionTable = (LPDWORD)(pImage + pExpDir->AddressOfFunctions);
+
+    if (pExpDir->NumberOfNames == 0)
+	return hInst;	// No export names.
+
+    // Check only the first entry.
+    if ((pFunctionTable[0] < ExpVA) || (pFunctionTable[0] >= ExpVA + ExpSize))
+	// The first entry is not a function forwarder.
+	return hInst;
+
+    // The first entry is a function forwarder.
+    // The name is represented as "DllName.FunctionName".
+    const char *name = (const char *)(pImage + pFunctionTable[0]);
+    const char *p = strchr(name, '.');
+    if (p == NULL)
+	return hInst;
+
+    // Extract DllName.
+    char buf[MAX_PATH];
+    if (p - name + 1 > sizeof(buf))
+	return NULL;
+    strncpy(buf, name, p - name);
+    buf[p - name] = '\0';
+    return GetModuleHandleA(buf);
+}
+#endif
+
 #if defined(DYNAMIC_GETTEXT) || defined(PROTO)
 # ifndef GETTEXT_DLL
 #  define GETTEXT_DLL "libintl.dll"

src/proto/os_win32.pro

@@ -5,6 +5,7 @@ int mch_is_gui_executable(void);
 HINSTANCE find_imported_module_by_funcname(HINSTANCE hInst, const char *funcname);
 void *get_dll_import_func(HINSTANCE hInst, const char *funcname);
 void *hook_dll_import_func(HINSTANCE hInst, const char *funcname, const void *hook);
+HINSTANCE get_forwarded_dll(HINSTANCE hInst);
 int dyn_libintl_init(void);
 void dyn_libintl_end(void);
 void PlatformId(void);

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1980,
 /**/
     1979,
 /**/