[lldb/Plugins] Improve error reporting with reading memory in Scripted Process

This patch improves the ScriptedPythonInterface::Dispatch method to
support passing lldb_private types to the python implementation.

This will allow, for instance, the Scripted Process python implementation
to report errors when reading memory back to lldb.

To do so, the Dispatch method will transform the private types in the
parameter pack into `PythonObject`s to be able to pass them down to the
python methods.

Then, if the call succeeded, the transformed arguments will be converted
back to their original type and re-assigned in the parameter pack, to
ensure pointers and references behaviours are preserved.

This patch also updates various scripted process python class and tests
to reflect this change.

rdar://100030995

Differential Revision: https://reviews.llvm.org/D134033

Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>

1 files changed, 61 insertions, 0 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h b/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
index 7e18b0e..30634c8 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
@@ -23,7 +23,68 @@
 #include "lldb/lldb-types.h"
 #include "llvm/Support/Error.h"
 
+namespace lldb {
+class SBEvent;
+class SBCommandReturnObject;
+class SBValue;
+class SBStream;
+class SBStructuredData;
+} // namespace lldb
+
 namespace lldb_private {
+namespace python {
+
+typedef struct swig_type_info swig_type_info;
+
+python::PythonObject ToSWIGHelper(void *obj, swig_type_info *info);
+
+/// A class that automatically clears an SB object when it goes out of scope.
+/// Use for cases where the SB object points to a temporary/unowned entity.
+template <typename T> class ScopedPythonObject : PythonObject {
+public:
+  ScopedPythonObject(T *sb, swig_type_info *info)
+      : PythonObject(ToSWIGHelper(sb, info)), m_sb(sb) {}
+  ~ScopedPythonObject() {
+    if (m_sb)
+      *m_sb = T();
+  }
+  ScopedPythonObject(ScopedPythonObject &&rhs)
+      : PythonObject(std::move(rhs)), m_sb(std::exchange(rhs.m_sb, nullptr)) {}
+  ScopedPythonObject(const ScopedPythonObject &) = delete;
+  ScopedPythonObject &operator=(const ScopedPythonObject &) = delete;
+  ScopedPythonObject &operator=(ScopedPythonObject &&) = delete;
+
+  const PythonObject &obj() const { return *this; }
+
+private:
+  T *m_sb;
+};
+
+PythonObject ToSWIGWrapper(lldb::ValueObjectSP value_sp);
+PythonObject ToSWIGWrapper(lldb::TargetSP target_sp);
+PythonObject ToSWIGWrapper(lldb::ProcessSP process_sp);
+PythonObject ToSWIGWrapper(lldb::ThreadPlanSP thread_plan_sp);
+PythonObject ToSWIGWrapper(lldb::BreakpointSP breakpoint_sp);
+PythonObject ToSWIGWrapper(const Status &status);
+PythonObject ToSWIGWrapper(const StructuredDataImpl &data_impl);
+PythonObject ToSWIGWrapper(lldb::ThreadSP thread_sp);
+PythonObject ToSWIGWrapper(lldb::StackFrameSP frame_sp);
+PythonObject ToSWIGWrapper(lldb::DebuggerSP debugger_sp);
+PythonObject ToSWIGWrapper(lldb::WatchpointSP watchpoint_sp);
+PythonObject ToSWIGWrapper(lldb::BreakpointLocationSP bp_loc_sp);
+PythonObject ToSWIGWrapper(lldb::ExecutionContextRefSP ctx_sp);
+PythonObject ToSWIGWrapper(const TypeSummaryOptions &summary_options);
+PythonObject ToSWIGWrapper(const SymbolContext &sym_ctx);
+
+PythonObject ToSWIGWrapper(std::unique_ptr<lldb::SBValue> value_sb);
+PythonObject ToSWIGWrapper(std::unique_ptr<lldb::SBStream> stream_sb);
+PythonObject ToSWIGWrapper(std::unique_ptr<lldb::SBStructuredData> data_sb);
+
+python::ScopedPythonObject<lldb::SBCommandReturnObject>
+ToSWIGWrapper(CommandReturnObject &cmd_retobj);
+python::ScopedPythonObject<lldb::SBEvent> ToSWIGWrapper(Event *event);
+
+} // namespace python
 
 // GetPythonValueFormatString provides a system independent type safe way to
 // convert a variable's type into a python value format. Python value formats