From d055e3a0eb4e957159b075c0937a960beb75c975 Mon Sep 17 00:00:00 2001
From: Pedro Tammela <pctammela@gmail.com>
Date: Fri, 27 Nov 2020 22:29:56 +0000
Subject: [PATCH] [LLDB/Python] Fix segfault on Python scripted entrypoints

The code that gets the ScriptInterpreter was not considering the
case that it receives a Lua interpreter.

Differential Revision: https://reviews.llvm.org/D92249
---
 .../Python/ScriptInterpreterPython.cpp        | 37 ++++++++++---------
 .../Python/scripted_breakpoint_lua.test       |  8 ++++
 2 files changed, 27 insertions(+), 18 deletions(-)
 create mode 100644 lldb/test/Shell/ScriptInterpreter/Python/scripted_breakpoint_lua.test

diff --git a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
index e5802ad041e4..0d13884e8089 100644
--- a/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
+++ b/lldb/source/Plugins/ScriptInterpreter/Python/ScriptInterpreterPython.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "lldb/Host/Config.h"
+#include "lldb/lldb-enumerations.h"
 
 #if LLDB_ENABLE_PYTHON
 
@@ -214,6 +215,12 @@ extern "C" void *
 LLDBSWIGPython_GetDynamicSetting(void *module, const char *setting,
                                  const lldb::TargetSP &target_sp);
 
+static ScriptInterpreterPythonImpl *GetPythonInterpreter(Debugger &debugger) {
+  ScriptInterpreter *script_interpreter =
+      debugger.GetScriptInterpreter(true, lldb::eScriptLanguagePython);
+  return static_cast<ScriptInterpreterPythonImpl *>(script_interpreter);
+}
+
 static bool g_initialized = false;
 
 namespace {
@@ -1825,11 +1832,10 @@ StructuredData::ObjectSP ScriptInterpreterPythonImpl::CreateScriptedThreadPlan(
     return {};
 
   Debugger &debugger = thread_plan_sp->GetTarget().GetDebugger();
-  ScriptInterpreter *script_interpreter = debugger.GetScriptInterpreter();
   ScriptInterpreterPythonImpl *python_interpreter =
-      static_cast<ScriptInterpreterPythonImpl *>(script_interpreter);
+      GetPythonInterpreter(debugger);
 
-  if (!script_interpreter)
+  if (!python_interpreter)
     return {};
 
   void *ret_val;
@@ -1929,11 +1935,10 @@ ScriptInterpreterPythonImpl::CreateScriptedBreakpointResolver(
     return StructuredData::GenericSP();
 
   Debugger &debugger = bkpt_sp->GetTarget().GetDebugger();
-  ScriptInterpreter *script_interpreter = debugger.GetScriptInterpreter();
   ScriptInterpreterPythonImpl *python_interpreter =
-      static_cast<ScriptInterpreterPythonImpl *>(script_interpreter);
+      GetPythonInterpreter(debugger);
 
-  if (!script_interpreter)
+  if (!python_interpreter)
     return StructuredData::GenericSP();
 
   void *ret_val;
@@ -2003,11 +2008,10 @@ StructuredData::GenericSP ScriptInterpreterPythonImpl::CreateScriptedStopHook(
     return StructuredData::GenericSP();
   }
 
-  ScriptInterpreter *script_interpreter = m_debugger.GetScriptInterpreter();
   ScriptInterpreterPythonImpl *python_interpreter =
-      static_cast<ScriptInterpreterPythonImpl *>(script_interpreter);
+      GetPythonInterpreter(m_debugger);
 
-  if (!script_interpreter) {
+  if (!python_interpreter) {
     error.SetErrorString("No script interpreter for scripted stop-hook.");
     return StructuredData::GenericSP();
   }
@@ -2103,11 +2107,10 @@ ScriptInterpreterPythonImpl::CreateSyntheticScriptedProvider(
     return StructuredData::ObjectSP();
 
   Debugger &debugger = target->GetDebugger();
-  ScriptInterpreter *script_interpreter = debugger.GetScriptInterpreter();
   ScriptInterpreterPythonImpl *python_interpreter =
-      (ScriptInterpreterPythonImpl *)script_interpreter;
+      GetPythonInterpreter(debugger);
 
-  if (!script_interpreter)
+  if (!python_interpreter)
     return StructuredData::ObjectSP();
 
   void *ret_val = nullptr;
@@ -2274,11 +2277,10 @@ bool ScriptInterpreterPythonImpl::BreakpointCallbackFunction(
     return true;
 
   Debugger &debugger = target->GetDebugger();
-  ScriptInterpreter *script_interpreter = debugger.GetScriptInterpreter();
   ScriptInterpreterPythonImpl *python_interpreter =
-      (ScriptInterpreterPythonImpl *)script_interpreter;
+      GetPythonInterpreter(debugger);
 
-  if (!script_interpreter)
+  if (!python_interpreter)
     return true;
 
   if (python_function_name && python_function_name[0]) {
@@ -2340,11 +2342,10 @@ bool ScriptInterpreterPythonImpl::WatchpointCallbackFunction(
     return true;
 
   Debugger &debugger = target->GetDebugger();
-  ScriptInterpreter *script_interpreter = debugger.GetScriptInterpreter();
   ScriptInterpreterPythonImpl *python_interpreter =
-      (ScriptInterpreterPythonImpl *)script_interpreter;
+      GetPythonInterpreter(debugger);
 
-  if (!script_interpreter)
+  if (!python_interpreter)
     return true;
 
   if (python_function_name && python_function_name[0]) {
diff --git a/lldb/test/Shell/ScriptInterpreter/Python/scripted_breakpoint_lua.test b/lldb/test/Shell/ScriptInterpreter/Python/scripted_breakpoint_lua.test
new file mode 100644
index 000000000000..c86ae9057c50
--- /dev/null
+++ b/lldb/test/Shell/ScriptInterpreter/Python/scripted_breakpoint_lua.test
@@ -0,0 +1,8 @@
+# REQUIRES: python
+# UNSUPPORTED: lldb-repro
+#
+# RUN: cat %s | %lldb --script-language lua 2>&1 | FileCheck %s
+b main
+breakpoint command add -s python -o 'print(frame); return False'
+run
+# CHECK: frame #0