feature_select: Apply tiny name switching optimization and cleanup

After the big optimization of selectable features, the cached
select Id-s can also be used to simplify the case selection.

Also, the MSVC glitch with signed bitfields is circumvented
by unsigned bitfields.

Further a merge error was reverted which killed
signature: Clean up and improve readability 3d4d91334
Christian Tismer <tismer@stackless.com> 10. Jul 2020 at 11:06

Change-Id: I783dc6d73b88016e70c58daeb207f1537fb38f72
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

3 files changed, 42 insertions, 29 deletions

diff --git a/sources/shiboken2/libshiboken/basewrapper_p.h b/sources/shiboken2/libshiboken/basewrapper_p.h
index 685b4fbe5..482a3ea2a 100644
--- a/sources/shiboken2/libshiboken/basewrapper_p.h
+++ b/sources/shiboken2/libshiboken/basewrapper_p.h
@@ -130,16 +130,16 @@ struct SbkObjectTypePrivate
     TypeDiscoveryFuncV2 type_discovery;
     /// Pointer to a function responsible for deletion of the C++ instance calling the proper destructor.
     ObjectDestructor cpp_dtor;
+    /// PYSIDE-1019: Caching the current select Id
+    unsigned int pyside_reserved_bits : 8;   // MSVC has bug with the sign bit!
     /// True if this type holds two or more C++ instances, e.g.: a Python class which inherits from two C++ classes.
-    int is_multicpp : 1;
+    unsigned int is_multicpp : 1;
     /// True if this type was defined by the user.
-    int is_user_type : 1;
+    unsigned int is_user_type : 1;
     /// Tells is the type is a value type or an object-type, see BEHAVIOUR_ *constants.
     // TODO-CONVERTERS: to be deprecated/removed
-    int type_behaviour : 2;
-    int delete_in_main_thread : 1;
-    /// PYSIDE-1019: Caching the current select Id
-    int pyside_reserved_bits : 9;   // MSVC needs the sign bit! Buglet?
+    unsigned int type_behaviour : 2;
+    unsigned int delete_in_main_thread : 1;
     /// C++ name
     char *original_name;
     /// Type user data
diff --git a/sources/shiboken2/libshiboken/bindingmanager.cpp b/sources/shiboken2/libshiboken/bindingmanager.cpp
index b35a02ef4..4f8c6068a 100644
--- a/sources/shiboken2/libshiboken/bindingmanager.cpp
+++ b/sources/shiboken2/libshiboken/bindingmanager.cpp
@@ -274,16 +274,10 @@ SbkObject *BindingManager::retrieveWrapper(const void *cptr)
     return iter->second;
 }
 
-static bool mangleNameFlag(PyTypeObject *type)
+static inline bool mangleNameFlag(PyTypeObject *type)
 {
     // PYSIDE-1019: See if a dict is set with a snake_case bit.
-    static PyTypeObject *old_dict_type = Py_TYPE(PyType_Type.tp_dict);
-    auto dict = type->tp_dict;
-    if (Py_TYPE(dict) == old_dict_type)
-        return false;
-    Shiboken::AutoDecRef select_id(PyObject_GetAttr(dict, Shiboken::PyName::select_id()));
-    auto id = PyInt_AsSsize_t(select_id);
-    return (id & 1) != 0;
+    return (SbkObjectType_GetReserved(type) & 1) != 0;
 }
 
 PyObject *BindingManager::getOverride(const void *cptr, PyObject *methodNameCache[2], const char *methodName)
diff --git a/sources/shiboken2/libshiboken/signature.cpp b/sources/shiboken2/libshiboken/signature.cpp
index 4614a131e..e4dc27ea7 100644
--- a/sources/shiboken2/libshiboken/signature.cpp
+++ b/sources/shiboken2/libshiboken/signature.cpp
@@ -653,17 +653,22 @@ _fixup_getset(PyTypeObject *type, const char *name, PyGetSetDef *new_gsp)
             }
         }
     }
-    // staticmethod has just a __doc__ in the class
-    assert(strcmp(type->tp_name, "staticmethod") == 0);
+    PyMemberDef *md = type->tp_members;
+    if (md != nullptr)
+        for (; md->name != nullptr; md++)
+            if (strcmp(md->name, name) == 0)
+                return 1;
+    // staticmethod has just a `__doc__` in the class
+    assert(strcmp(type->tp_name, "staticmethod") == 0 && strcmp(name, "__doc__") == 0);
     return 0;
 }
 
 static int
-add_more_getsets(PyTypeObject *type, PyGetSetDef *gsp, PyObject **old_descr)
+add_more_getsets(PyTypeObject *type, PyGetSetDef *gsp, PyObject **doc_descr)
 {
     /*
-     * This function is used to assign a new __signature__ attribute,
-     * and also to override a __doc__ attribute.
+     * This function is used to assign a new `__signature__` attribute,
+     * and also to override a `__doc__` or `__name__` attribute.
      */
     assert(PyType_Check(type));
     PyType_Ready(type);
@@ -671,9 +676,11 @@ add_more_getsets(PyTypeObject *type, PyGetSetDef *gsp, PyObject **old_descr)
     for (; gsp->name != nullptr; gsp++) {
         PyObject *have_descr = PyDict_GetItemString(dict, gsp->name);
         if (have_descr != nullptr) {
-            assert(strcmp(gsp->name, "__doc__") == 0);
             Py_INCREF(have_descr);
-            *old_descr = have_descr;
+            if (strcmp(gsp->name, "__doc__") == 0)
+                *doc_descr = have_descr;
+            else
+                assert(false);
             if (!_fixup_getset(type, gsp->name, gsp))
                 continue;
         }
@@ -824,7 +831,7 @@ static PyGetSetDef new_PyWrapperDescr_getsets[] = {
 //
 // Additionally to the interface via __signature__, we also provide
 // a general function, which allows for different signature layouts.
-// The "modifier" argument is a string that is passed in from loader.py .
+// The "modifier" argument is a string that is passed in from 'loader.py'.
 // Configuration what the modifiers mean is completely in Python.
 //
 
@@ -909,13 +916,25 @@ PySide_PatchTypes(void)
                                         reinterpret_cast<PyObject *>(&PyString_Type), "split"));
         Shiboken::AutoDecRef wrap_descr(PyObject_GetAttrString(
                                         reinterpret_cast<PyObject *>(Py_TYPE(Py_True)), "__add__"));
+        // abbreviations for readability
+        auto md_gs = new_PyMethodDescr_getsets;
+        auto md_doc = &old_md_doc_descr;
+        auto cf_gs = new_PyCFunction_getsets;
+        auto cf_doc = &old_cf_doc_descr;
+        auto sm_gs = new_PyStaticMethod_getsets;
+        auto sm_doc = &old_sm_doc_descr;
+        auto tp_gs = new_PyType_getsets;
+        auto tp_doc = &old_tp_doc_descr;
+        auto wd_gs = new_PyWrapperDescr_getsets;
+        auto wd_doc = &old_wd_doc_descr;
+
         if (meth_descr.isNull() || wrap_descr.isNull()
             || PyType_Ready(Py_TYPE(meth_descr)) < 0
-            || add_more_getsets(PepMethodDescr_TypePtr,  new_PyMethodDescr_getsets,  &old_md_doc_descr) < 0
-            || add_more_getsets(&PyCFunction_Type,       new_PyCFunction_getsets,    &old_cf_doc_descr) < 0
-            || add_more_getsets(PepStaticMethod_TypePtr, new_PyStaticMethod_getsets, &old_sm_doc_descr) < 0
-            || add_more_getsets(&PyType_Type,            new_PyType_getsets,         &old_tp_doc_descr) < 0
-            || add_more_getsets(Py_TYPE(wrap_descr),     new_PyWrapperDescr_getsets, &old_wd_doc_descr) < 0
+            || add_more_getsets(PepMethodDescr_TypePtr,  md_gs, md_doc) < 0
+            || add_more_getsets(&PyCFunction_Type,       cf_gs, cf_doc) < 0
+            || add_more_getsets(PepStaticMethod_TypePtr, sm_gs, sm_doc) < 0
+            || add_more_getsets(&PyType_Type,            tp_gs, tp_doc) < 0
+            || add_more_getsets(Py_TYPE(wrap_descr),     wd_gs, wd_doc) < 0
             )
             return -1;
 #ifndef _WIN32
@@ -1214,8 +1233,8 @@ FinishSignatureInitialization(PyObject *module, const char *signatures[])
      * Still, it is not possible to call init phase 2 from here,
      * because the import is still running. Do it from Python!
      */
-    PySide_PatchTypes();
-    if (PySide_FinishSignatures(module, signatures) < 0) {
+    if (   PySide_PatchTypes() < 0
+        || PySide_FinishSignatures(module, signatures) < 0) {
         PyErr_Print();
         PyErr_SetNone(PyExc_ImportError);
     }