[lldb] Make use of Scripted{Python,}Interface for ScriptedThreadPlan (#70392)

This patch makes ScriptedThreadPlan conforming to the ScriptedInterface
& ScriptedPythonInterface facilities by introducing 2
ScriptedThreadPlanInterface & ScriptedThreadPlanPythonInterface classes.

This allows us to get rid of every ScriptedThreadPlan-specific SWIG
method and re-use the same affordances as other scripting offordances,
like Scripted{Process,Thread,Platform} & OperatingSystem.

To do so, this adds new transformer methods for `ThreadPlan`, `Stream` &
`Event`, to allow the bijection between C++ objects and their python
counterparts.

Signed-off-by: Med Ismail Bennani <[email protected]>

Author: medismailben

lldb/bindings/python/python-swigsafecast.swig

@@ -37,10 +37,6 @@ PythonObject SWIGBridge::ToSWIGWrapper(const Status& status) {
   return ToSWIGHelper(new lldb::SBError(status), SWIGTYPE_p_lldb__SBError);
 }
 
-PythonObject SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStream> stream_sb) {
-  return ToSWIGHelper(stream_sb.release(), SWIGTYPE_p_lldb__SBStream);
-}
-
 PythonObject SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStructuredData> data_sb) {
   return ToSWIGHelper(data_sb.release(), SWIGTYPE_p_lldb__SBStructuredData);
 }
@@ -115,9 +111,16 @@ SWIGBridge::ToSWIGWrapper(CommandReturnObject &cmd_retobj) {
       SWIGTYPE_p_lldb__SBCommandReturnObject);
 }
 
-ScopedPythonObject<lldb::SBEvent> SWIGBridge::ToSWIGWrapper(Event *event) {
-  return ScopedPythonObject<lldb::SBEvent>(new lldb::SBEvent(event),
-                                           SWIGTYPE_p_lldb__SBEvent);
+PythonObject SWIGBridge::ToSWIGWrapper(const Stream *s) {
+  return ToSWIGHelper(new lldb::SBStream(), SWIGTYPE_p_lldb__SBStream);
+}
+
+PythonObject SWIGBridge::ToSWIGWrapper(std::shared_ptr<lldb::SBStream> stream_sb) {
+  return ToSWIGHelper(stream_sb.get(), SWIGTYPE_p_lldb__SBStream);
+}
+
+PythonObject SWIGBridge::ToSWIGWrapper(Event *event) {
+  return ToSWIGHelper(new lldb::SBEvent(event), SWIGTYPE_p_lldb__SBEvent);
 }
 
 PythonObject SWIGBridge::ToSWIGWrapper(

lldb/bindings/python/python-wrapper.swig

@@ -229,133 +229,6 @@ PythonObject lldb_private::python::SWIGBridge::LLDBSwigPythonCreateCommandObject
   return pfunc(SWIGBridge::ToSWIGWrapper(std::move(debugger_sp)), dict);
 }
 
-PythonObject lldb_private::python::SWIGBridge::LLDBSwigPythonCreateScriptedThreadPlan(
-    const char *python_class_name, const char *session_dictionary_name,
-    const lldb_private::StructuredDataImpl &args_impl,
-    std::string &error_string, const lldb::ThreadPlanSP &thread_plan_sp) {
-  if (python_class_name == NULL || python_class_name[0] == '\0' ||
-      !session_dictionary_name)
-    return PythonObject();
-
-  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()) {
-    error_string.append("could not find script class: ");
-    error_string.append(python_class_name);
-    return PythonObject();
-  }
-
-  PythonObject tp_arg = SWIGBridge::ToSWIGWrapper(thread_plan_sp);
-
-  llvm::Expected<PythonCallable::ArgInfo> arg_info = pfunc.GetArgInfo();
-  if (!arg_info) {
-    llvm::handleAllErrors(
-        arg_info.takeError(),
-        [&](PythonException &E) { error_string.append(E.ReadBacktrace()); },
-        [&](const llvm::ErrorInfoBase &E) {
-          error_string.append(E.message());
-        });
-    return PythonObject();
-  }
-
-  PythonObject result = {};
-  auto args_sb = std::unique_ptr<lldb::SBStructuredData>(new lldb::SBStructuredData(args_impl));
-  if (arg_info.get().max_positional_args == 2) {
-    if (args_sb->IsValid()) {
-      error_string.assign(
-          "args passed, but __init__ does not take an args dictionary");
-      return PythonObject();
-    }
-    result = pfunc(tp_arg, dict);
-  } else if (arg_info.get().max_positional_args >= 3) {
-    result = pfunc(tp_arg, SWIGBridge::ToSWIGWrapper(std::move(args_sb)), dict);
-  } else {
-    error_string.assign("wrong number of arguments in __init__, should be 2 or "
-                        "3 (not including self)");
-    return PythonObject();
-  }
-
-  // FIXME: At this point we should check that the class we found supports all
-  // the methods that we need.
-
-  return result;
-}
-
-bool lldb_private::python::SWIGBridge::LLDBSWIGPythonCallThreadPlan(
-    void *implementor, const char *method_name, lldb_private::Event *event,
-    bool &got_error) {
-  got_error = false;
-
-  PyErr_Cleaner py_err_cleaner(false);
-  PythonObject self(PyRefType::Borrowed, static_cast<PyObject *>(implementor));
-  auto pfunc = self.ResolveName<PythonCallable>(method_name);
-
-  if (!pfunc.IsAllocated())
-    return false;
-
-  PythonObject result;
-  if (event != nullptr) {
-    ScopedPythonObject<SBEvent> event_arg = SWIGBridge::ToSWIGWrapper(event);
-    result = pfunc(event_arg.obj());
-  } else
-    result = pfunc();
-
-  if (PyErr_Occurred()) {
-    got_error = true;
-    printf("Return value was neither false nor true for call to %s.\n",
-           method_name);
-    PyErr_Print();
-    return false;
-  }
-
-  if (result.get() == Py_True)
-    return true;
-  else if (result.get() == Py_False)
-    return false;
-
-  // Somebody returned the wrong thing...
-  got_error = true;
-  printf("Wrong return value type for call to %s.\n", method_name);
-  return false;
-}
-
-bool lldb_private::python::SWIGBridge::LLDBSWIGPythonCallThreadPlan(
-    void *implementor, const char *method_name, lldb_private::Stream *stream,
-    bool &got_error) {
-  got_error = false;
-
-  PyErr_Cleaner py_err_cleaner(false);
-  PythonObject self(PyRefType::Borrowed, static_cast<PyObject *>(implementor));
-  auto pfunc = self.ResolveName<PythonCallable>(method_name);
-
-  if (!pfunc.IsAllocated()) 
-    return false;
-
-  auto *sb_stream = new lldb::SBStream();
-  PythonObject sb_stream_arg =
-      SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStream>(sb_stream));
-
-  PythonObject result;
-  result = pfunc(sb_stream_arg);
-
-  if (PyErr_Occurred()) {
-    printf("Error occured for call to %s.\n",
-           method_name);
-    PyErr_Print();
-    got_error = true;
-    return false;
-  }
-  if (stream)
-    stream->PutCString(sb_stream->GetData());
-  return true;
-
-}
-
 PythonObject lldb_private::python::SWIGBridge::LLDBSwigPythonCreateScriptedBreakpointResolver(
     const char *python_class_name, const char *session_dictionary_name,
     const StructuredDataImpl &args_impl,
@@ -500,9 +373,8 @@ bool lldb_private::python::SWIGBridge::LLDBSwigPythonStopHookCallHandleStop(
   if (!pfunc.IsAllocated())
     return true;
 
-  auto *sb_stream = new lldb::SBStream();
-  PythonObject sb_stream_arg =
-      SWIGBridge::ToSWIGWrapper(std::unique_ptr<lldb::SBStream>(sb_stream));
+  std::shared_ptr<lldb::SBStream> sb_stream = std::make_shared<lldb::SBStream>();
+  PythonObject sb_stream_arg = SWIGBridge::ToSWIGWrapper(sb_stream);
   PythonObject result =
       pfunc(SWIGBridge::ToSWIGWrapper(std::move(exc_ctx_sp)), sb_stream_arg);
 
@@ -517,6 +389,7 @@ bool lldb_private::python::SWIGBridge::LLDBSwigPythonStopHookCallHandleStop(
   // makes an internally help StreamString which I can't interpose, so I
   // have to copy it over here.
   stream->PutCString(sb_stream->GetData());
+  sb_stream_arg.release();
 
   if (result.get() == Py_False)
     return false;
@@ -753,6 +626,30 @@ void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBError(PyObject * data
   return sb_ptr;
 }
 
+void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBEvent(PyObject * data) {
+  lldb::SBEvent *sb_ptr = nullptr;
+
+  int valid_cast =
+      SWIG_ConvertPtr(data, (void **)&sb_ptr, SWIGTYPE_p_lldb__SBEvent, 0);
+
+  if (valid_cast == -1)
+    return NULL;
+
+  return sb_ptr;
+}
+
+void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBStream(PyObject * data) {
+  lldb::SBStream *sb_ptr = nullptr;
+
+  int valid_cast =
+      SWIG_ConvertPtr(data, (void **)&sb_ptr, SWIGTYPE_p_lldb__SBStream, 0);
+
+  if (valid_cast == -1)
+    return NULL;
+
+  return sb_ptr;
+}
+
 void *lldb_private::python::LLDBSWIGPython_CastPyObjectToSBValue(PyObject * data) {
   lldb::SBValue *sb_ptr = NULL;
 

lldb/include/lldb/API/SBEvent.h

@@ -15,6 +15,7 @@
 #include <vector>
 
 namespace lldb_private {
+class ScriptInterpreter;
 namespace python {
 class SWIGBridge;
 }
@@ -73,11 +74,12 @@ class LLDB_API SBEvent {
   friend class SBThread;
   friend class SBWatchpoint;
 
+  friend class lldb_private::ScriptInterpreter;
   friend class lldb_private::python::SWIGBridge;
 
   SBEvent(lldb::EventSP &event_sp);
 
-  SBEvent(lldb_private::Event *event_sp);
+  SBEvent(lldb_private::Event *event);
 
   lldb::EventSP &GetSP() const;
 

lldb/include/lldb/API/SBStream.h

@@ -13,6 +13,10 @@
 
 #include "lldb/API/SBDefines.h"
 
+namespace lldb_private {
+class ScriptInterpreter;
+} // namespace lldb_private
+
 namespace lldb {
 
 class LLDB_API SBStream {
@@ -101,6 +105,8 @@ class LLDB_API SBStream {
   friend class SBValue;
   friend class SBWatchpoint;
 
+  friend class lldb_private::ScriptInterpreter;
+
   lldb_private::Stream *operator->();
 
   lldb_private::Stream *get();

lldb/include/lldb/Interpreter/Interfaces/ScriptedInterface.h

@@ -10,7 +10,6 @@
 #define LLDB_INTERPRETER_INTERFACES_SCRIPTEDINTERFACE_H
 
 #include "lldb/Core/StructuredDataImpl.h"
-#include "lldb/Target/ExecutionContext.h"
 #include "lldb/Utility/LLDBLog.h"
 #include "lldb/Utility/Log.h"
 #include "lldb/Utility/UnimplementedError.h"
@@ -52,7 +51,8 @@ class ScriptedInterface {
   }
 
   template <typename T = StructuredData::ObjectSP>
-  bool CheckStructuredDataObject(llvm::StringRef caller, T obj, Status &error) {
+  static bool CheckStructuredDataObject(llvm::StringRef caller, T obj,
+                                        Status &error) {
     if (!obj)
       return ErrorWithMessage<bool>(caller, "Null Structured Data object",
                                     error);

lldb/include/lldb/Interpreter/Interfaces/ScriptedThreadPlanInterface.h

@@ -0,0 +1,38 @@
+//===-- ScriptedThreadPlanInterface.h ---------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLDB_INTERPRETER_INTERFACES_SCRIPTEDTHREADPLANINTERFACE_H
+#define LLDB_INTERPRETER_INTERFACES_SCRIPTEDTHREADPLANINTERFACE_H
+
+#include "lldb/lldb-private.h"
+
+#include "ScriptedInterface.h"
+
+namespace lldb_private {
+class ScriptedThreadPlanInterface : public ScriptedInterface {
+public:
+  virtual llvm::Expected<StructuredData::GenericSP>
+  CreatePluginObject(llvm::StringRef class_name,
+                     lldb::ThreadPlanSP thread_plan_sp,
+                     const StructuredDataImpl &args_sp) = 0;
+
+  virtual llvm::Expected<bool> ExplainsStop(Event *event) { return true; }
+
+  virtual llvm::Expected<bool> ShouldStop(Event *event) { return true; }
+
+  virtual llvm::Expected<bool> IsStale() { return true; };
+
+  virtual lldb::StateType GetRunState() { return lldb::eStateStepping; }
+
+  virtual llvm::Expected<bool> GetStopDescription(lldb_private::Stream *s) {
+    return true;
+  }
+};
+} // namespace lldb_private
+
+#endif // LLDB_INTERPRETER_INTERFACES_SCRIPTEDTHREADPLANINTERFACE_H