[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

6 files changed, 26 insertions, 33 deletions

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h b/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
index c7af135..56365a9 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/SWIGPythonBridge.h
@@ -57,20 +57,20 @@ void *LLDBSWIGPython_CastPyObjectToSBMemoryRegionInfo(PyObject *data);
 void *LLDBSwigPythonCreateScriptedProcess(const char *python_class_name,
                                           const char *session_dictionary_name,
                                           const lldb::TargetSP &target_sp,
-                                          StructuredDataImpl *args_impl,
+                                          const StructuredDataImpl &args_impl,
                                           std::string &error_string);
 
 void *LLDBSwigPythonCreateScriptedThread(const char *python_class_name,
                                          const char *session_dictionary_name,
                                          const lldb::ProcessSP &process_sp,
-                                         StructuredDataImpl *args_impl,
+                                         const StructuredDataImpl &args_impl,
                                          std::string &error_string);
 
 llvm::Expected<bool> LLDBSwigPythonBreakpointCallbackFunction(
     const char *python_function_name, const char *session_dictionary_name,
     const lldb::StackFrameSP &sb_frame,
     const lldb::BreakpointLocationSP &sb_bp_loc,
-    lldb_private::StructuredDataImpl *args_impl);
+    const lldb_private::StructuredDataImpl &args_impl);
 
 bool LLDBSwigPythonWatchpointCallbackFunction(
     const char *python_function_name, const char *session_dictionary_name,
@@ -94,7 +94,7 @@ void *LLDBSwigPythonCreateCommandObject(const char *python_class_name,
 
 void *LLDBSwigPythonCreateScriptedThreadPlan(
     const char *python_class_name, const char *session_dictionary_name,
-    lldb_private::StructuredDataImpl *args_data, std::string &error_string,
+    const StructuredDataImpl &args_data, std::string &error_string,
     const lldb::ThreadPlanSP &thread_plan_sp);
 
 bool LLDBSWIGPythonCallThreadPlan(void *implementor, const char *method_name,
@@ -103,16 +103,17 @@ bool LLDBSWIGPythonCallThreadPlan(void *implementor, const char *method_name,
 
 void *LLDBSwigPythonCreateScriptedBreakpointResolver(
     const char *python_class_name, const char *session_dictionary_name,
-    lldb_private::StructuredDataImpl *args, const lldb::BreakpointSP &bkpt_sp);
+    const StructuredDataImpl &args, const lldb::BreakpointSP &bkpt_sp);
 
 unsigned int
 LLDBSwigPythonCallBreakpointResolver(void *implementor, const char *method_name,
                                      lldb_private::SymbolContext *sym_ctx);
 
-void *LLDBSwigPythonCreateScriptedStopHook(
-    lldb::TargetSP target_sp, const char *python_class_name,
-    const char *session_dictionary_name, lldb_private::StructuredDataImpl *args,
-    lldb_private::Status &error);
+void *LLDBSwigPythonCreateScriptedStopHook(lldb::TargetSP target_sp,
+                                           const char *python_class_name,
+                                           const char *session_dictionary_name,
+                                           const StructuredDataImpl &args,
+                                           lldb_private::Status &error);
 
 bool LLDBSwigPythonStopHookCallHandleStop(void *implementor,
                                           lldb::ExecutionContextRefSP exc_ctx,
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index 5f282d7..9187129 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -1718,7 +1718,7 @@ StructuredData::DictionarySP ScriptInterpreterPythonImpl::OSPlugin_CreateThread(
 }
 
 StructuredData::ObjectSP ScriptInterpreterPythonImpl::CreateScriptedThreadPlan(
-    const char *class_name, StructuredDataImpl *args_data,
+    const char *class_name, const StructuredDataImpl &args_data,
     std::string &error_str, lldb::ThreadPlanSP thread_plan_sp) {
   if (class_name == nullptr || class_name[0] == '\0')
     return StructuredData::ObjectSP();
@@ -1820,7 +1820,7 @@ lldb::StateType ScriptInterpreterPythonImpl::ScriptedThreadPlanGetRunState(
 
 StructuredData::GenericSP
 ScriptInterpreterPythonImpl::CreateScriptedBreakpointResolver(
-    const char *class_name, StructuredDataImpl *args_data,
+    const char *class_name, const StructuredDataImpl &args_data,
     lldb::BreakpointSP &bkpt_sp) {
 
   if (class_name == nullptr || class_name[0] == '\0')
@@ -1890,8 +1890,8 @@ ScriptInterpreterPythonImpl::ScriptedBreakpointResolverSearchDepth(
 }
 
 StructuredData::GenericSP ScriptInterpreterPythonImpl::CreateScriptedStopHook(
-    TargetSP target_sp, const char *class_name, StructuredDataImpl *args_data,
-    Status &error) {
+    TargetSP target_sp, const char *class_name,
+    const StructuredDataImpl &args_data, Status &error) {
 
   if (!target_sp) {
     error.SetErrorString("No target for scripted stop-hook.");
@@ -2197,7 +2197,7 @@ bool ScriptInterpreterPythonImpl::BreakpointCallbackFunction(
               LLDBSwigPythonBreakpointCallbackFunction(
                   python_function_name,
                   python_interpreter->m_dictionary_name.c_str(), stop_frame_sp,
-                  bp_loc_sp, bp_option_data->m_extra_args_up.get());
+                  bp_loc_sp, bp_option_data->m_extra_args);
 
           if (!maybe_ret_val) {
 
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h
index 8cfc24e..2e8301a 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.h
@@ -33,13 +33,12 @@ public:
     CommandDataPython() : BreakpointOptions::CommandData() {
       interpreter = lldb::eScriptLanguagePython;
     }
-    CommandDataPython(StructuredData::ObjectSP extra_args_sp) :
-        BreakpointOptions::CommandData(),
-        m_extra_args_up(new StructuredDataImpl()) {
-        interpreter = lldb::eScriptLanguagePython;
-        m_extra_args_up->SetObjectSP(extra_args_sp);
+    CommandDataPython(StructuredData::ObjectSP extra_args_sp)
+        : BreakpointOptions::CommandData(),
+          m_extra_args(std::move(extra_args_sp)) {
+      interpreter = lldb::eScriptLanguagePython;
     }
-    lldb::StructuredDataImplUP m_extra_args_up;
+    StructuredDataImpl m_extra_args;
   };
 
   ScriptInterpreterPython(Debugger &debugger)
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
index a3f83b6..defc2ac 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPythonImpl.h
@@ -79,7 +79,7 @@ public:
 
   StructuredData::ObjectSP
   CreateScriptedThreadPlan(const char *class_name,
-                           StructuredDataImpl *args_data,
+                           const StructuredDataImpl &args_data,
                            std::string &error_str,
                            lldb::ThreadPlanSP thread_plan) override;
 
@@ -99,7 +99,7 @@ public:
 
   StructuredData::GenericSP
   CreateScriptedBreakpointResolver(const char *class_name,
-                                   StructuredDataImpl *args_data,
+                                   const StructuredDataImpl &args_data,
                                    lldb::BreakpointSP &bkpt_sp) override;
   bool ScriptedBreakpointResolverSearchCallback(
       StructuredData::GenericSP implementor_sp,
@@ -110,7 +110,8 @@ public:
 
   StructuredData::GenericSP
   CreateScriptedStopHook(lldb::TargetSP target_sp, const char *class_name,
-                         StructuredDataImpl *args_data, Status &error) override;
+                         const StructuredDataImpl &args_data,
+                         Status &error) override;
 
   bool ScriptedStopHookHandleStop(StructuredData::GenericSP implementor_sp,
                                   ExecutionContext &exc_ctx,
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.cpp
index 29680da..e3c1931 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedProcessPythonInterface.cpp
@@ -37,11 +37,7 @@ StructuredData::GenericSP ScriptedProcessPythonInterface::CreatePluginObject(
     return {};
 
   TargetSP target_sp = exe_ctx.GetTargetSP();
-  StructuredDataImpl *args_impl = nullptr;
-  if (args_sp) {
-    args_impl = new StructuredDataImpl();
-    args_impl->SetObjectSP(args_sp);
-  }
+  StructuredDataImpl args_impl(args_sp);
   std::string error_string;
 
   Locker py_lock(&m_interpreter, Locker::AcquireLock | Locker::NoSTDIN,
diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedThreadPythonInterface.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedThreadPythonInterface.cpp
index d2c28bc..6a881bf 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedThreadPythonInterface.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptedThreadPythonInterface.cpp
@@ -37,11 +37,7 @@ StructuredData::GenericSP ScriptedThreadPythonInterface::CreatePluginObject(
     return {};
 
   ProcessSP process_sp = exe_ctx.GetProcessSP();
-  StructuredDataImpl *args_impl = nullptr;
-  if (args_sp) {
-    args_impl = new StructuredDataImpl();
-    args_impl->SetObjectSP(args_sp);
-  }
+  StructuredDataImpl args_impl(args_sp);
   std::string error_string;
 
   Locker py_lock(&m_interpreter, Locker::AcquireLock | Locker::NoSTDIN,