[lldb] Clarify StructuredDataImpl ownership

StructuredDataImpl ownership semantics is unclear at best. Various
structures were holding a non-owning pointer to it, with a comment that
the object is owned somewhere else. From what I was able to gather that
"somewhere else" was the SBStructuredData object, but I am not sure that
all created object eventually made its way there. (It wouldn't matter
even if they did, as we are leaking most of our SBStructuredData
objects.)

Since StructuredDataImpl is just a collection of two (shared) pointers,
there's really no point in elaborate lifetime management, so this patch
replaces all StructuredDataImpl pointers with actual objects or
unique_ptrs to it. This makes it much easier to resolve SBStructuredData
leaks in a follow-up patch.

Differential Revision: https://reviews.llvm.org/D114791

1 files changed, 16 insertions, 11 deletions

diff --git a/lldb/bindings/python/python-wrapper.swig b/lldb/bindings/python/python-wrapper.swig
index 079f8d12dafa..da943f73c435 100644
--- a/lldb/bindings/python/python-wrapper.swig
+++ b/lldb/bindings/python/python-wrapper.swig
@@ -29,7 +29,7 @@ lldb_private::LLDBSwigPythonBreakpointCallbackFunction
     const char *session_dictionary_name,
     const lldb::StackFrameSP& frame_sp,
     const lldb::BreakpointLocationSP& bp_loc_sp,
-    lldb_private::StructuredDataImpl *args_impl
+    const lldb_private::StructuredDataImpl &args_impl
 )
 {
     using namespace llvm;
@@ -254,7 +254,7 @@ lldb_private::LLDBSwigPythonCreateScriptedProcess
     const char *python_class_name,
     const char *session_dictionary_name,
     const lldb::TargetSP& target_sp,
-    lldb_private::StructuredDataImpl *args_impl,
+    const lldb_private::StructuredDataImpl &args_impl,
     std::string &error_string
 )
 {
@@ -290,7 +290,9 @@ lldb_private::LLDBSwigPythonCreateScriptedProcess
     PythonObject result = {};
     if (arg_info.get().max_positional_args == 2) {
         // FIXME: SBStructuredData leaked here
-        PythonObject args_arg(PyRefType::Owned, SBTypeToSWIGWrapper(*new lldb::SBStructuredData(args_impl)));
+        PythonObject args_arg(
+            PyRefType::Owned,
+            SBTypeToSWIGWrapper(*new lldb::SBStructuredData(args_impl)));
         result = pfunc(target_arg, args_arg);
     } else {
         error_string.assign("wrong number of arguments in __init__, should be 2 (not including self)");
@@ -308,7 +310,7 @@ lldb_private::LLDBSwigPythonCreateScriptedThread
     const char *python_class_name,
     const char *session_dictionary_name,
     const lldb::ProcessSP& process_sp,
-    lldb_private::StructuredDataImpl *args_impl,
+    const StructuredDataImpl &args_impl,
     std::string &error_string
 )
 {
@@ -342,7 +344,9 @@ lldb_private::LLDBSwigPythonCreateScriptedThread
     PythonObject result = {};
     if (arg_info.get().max_positional_args == 2) {
         // FIXME: SBStructuredData leaked here
-        PythonObject args_arg(PyRefType::Owned, SBTypeToSWIGWrapper(*new lldb::SBStructuredData(args_impl)));
+        PythonObject args_arg(
+            PyRefType::Owned,
+            SBTypeToSWIGWrapper(*new lldb::SBStructuredData(args_impl)));
         result = pfunc(ToSWIGWrapper(process_sp), args_arg);
     } else {
         error_string.assign("wrong number of arguments in __init__, should be 2 (not including self)");
@@ -359,7 +363,7 @@ lldb_private::LLDBSwigPythonCreateScriptedThreadPlan
 (
     const char *python_class_name,
     const char *session_dictionary_name,
-    lldb_private::StructuredDataImpl *args_impl,
+    const lldb_private::StructuredDataImpl &args_impl,
     std::string &error_string,
     const lldb::ThreadPlanSP& thread_plan_sp
 )
@@ -395,15 +399,16 @@ lldb_private::LLDBSwigPythonCreateScriptedThreadPlan
     }
 
     PythonObject result = {};
+    // FIXME: SBStructuredData leaked here
+    auto *args_sb = new lldb::SBStructuredData(args_impl);
     if (arg_info.get().max_positional_args == 2) {
-        if (args_impl != nullptr) {
+        if (args_sb->IsValid()) {
            error_string.assign("args passed, but __init__ does not take an args dictionary");
            Py_RETURN_NONE;
         }
         result = pfunc(tp_arg, dict);
     } else if (arg_info.get().max_positional_args >= 3) {
-        // FIXME: SBStructuredData leaked here
-        PythonObject args_arg(PyRefType::Owned, SBTypeToSWIGWrapper(*new lldb::SBStructuredData(args_impl)));
+        PythonObject args_arg(PyRefType::Owned, SBTypeToSWIGWrapper(*args_sb));
         result = pfunc(tp_arg, args_arg, dict);
     } else {
         error_string.assign("wrong number of arguments in __init__, should be 2 or 3 (not including self)");
@@ -467,7 +472,7 @@ lldb_private::LLDBSWIGPythonCallThreadPlan
 
 void *lldb_private::LLDBSwigPythonCreateScriptedBreakpointResolver(
     const char *python_class_name, const char *session_dictionary_name,
-    lldb_private::StructuredDataImpl *args_impl,
+    const StructuredDataImpl &args_impl,
     const lldb::BreakpointSP &breakpoint_sp) {
 
     if (python_class_name == NULL || python_class_name[0] == '\0' || !session_dictionary_name)
@@ -558,7 +563,7 @@ lldb_private::LLDBSwigPythonCreateScriptedStopHook
     lldb::TargetSP target_sp,
     const char *python_class_name,
     const char *session_dictionary_name,
-    lldb_private::StructuredDataImpl *args_impl,
+    const StructuredDataImpl &args_impl,
     Status &error
 )
 {