[lldb] Introduce StackFrameRecognizer [take 2]

This patch introduces a concept of "frame recognizer" and "recognized frame". This should be an extensible mechanism that retrieves information about special frames based on ABI, arguments or other special properties of that frame, even without source code. A few examples where that could be useful could be 1) objc_exception_throw, where we'd like to get the current exception, 2) terminate_with_reason and extracting the current terminate string, 3) recognizing Objective-C frames and automatically extracting the receiver+selector, or perhaps all arguments (based on selector).

Differential Revision: https://reviews.llvm.org/D44603

llvm-svn: 345686

lldb/scripts/Python/python-wrapper.swig

@@ -784,6 +784,52 @@ LLDBSWIGPythonCreateOSPlugin
     Py_RETURN_NONE;
 }
 
+SWIGEXPORT void*
+LLDBSWIGPython_CreateFrameRecognizer
+(
+    const char *python_class_name,
+    const char *session_dictionary_name
+)
+{
+    using namespace lldb_private;
+
+    if (python_class_name == NULL || python_class_name[0] == '\0' || !session_dictionary_name)
+        Py_RETURN_NONE;
+
+    PyErr_Cleaner py_err_cleaner(true);
+
+    auto dict = PythonModule::MainModule().ResolveName<PythonDictionary>(session_dictionary_name);
+    auto pfunc = PythonObject::ResolveNameWithDictionary<PythonCallable>(python_class_name, dict);
+
+    if (!pfunc.IsAllocated())
+        Py_RETURN_NONE;
+
+    auto result = pfunc();
+
+    if (result.IsAllocated())
+        return result.release();
+
+    Py_RETURN_NONE;
+}
+
+SWIGEXPORT PyObject*
+LLDBSwigPython_GetRecognizedArguments
+(
+    PyObject *implementor,
+    const lldb::StackFrameSP& frame_sp
+)
+{
+    using namespace lldb_private;
+
+    static char callee_name[] = "get_recognized_arguments";
+
+    lldb::SBFrame frame_sb(frame_sp);
+    PyObject *arg = SBTypeToSWIGWrapper(frame_sb);
+
+    PyObject* result = PyObject_CallMethodObjArgs(implementor, PyString_FromString(callee_name), arg, NULL);
+    return result;
+}
+
 SWIGEXPORT void*
 LLDBSWIGPython_GetDynamicSetting (void* module, const char* setting, const lldb::TargetSP& target_sp)
 {