[Lldb-commits] [lldb] [lldb] Fix assert in ScriptedProcess destructor (PR #71744)

[Med Ismail Bennani via lldb-commits]

https://github.com/medismailben updated https://github.com/llvm/llvm-project/pull/71744

>From a0617d18d1cbcf0ca21ca01b350a22930414991f Mon Sep 17 00:00:00 2001
From: Med Ismail Bennani <ismail at bennani.ma>
Date: Wed, 8 Nov 2023 17:01:07 -0800
Subject: [PATCH] [lldb] Fix assert in ScriptedProcess destructor

This patch should fix a test failure in `Expr/TestIRMemoryMapWindows.test`:

https://lab.llvm.org/buildbot/#/builders/219/builds/6786

The problem here is that since 7991412 landed, all the
`ScriptInterpreter::CreateScripted*Interface` now return a `nullptr`
when using the base `ScriptInterpreter` instance, instead of
`ScriptInterpreterPython` for instance.

This nullptr is actually well handled in the various places where we
create a Scripted Interface, however, because of the way to instanciate
a process, the process plugin manager have to iterate over every process
plugin and call the `CreateInstance` static function that should
instanciate the right object.

So in the ScriptedProcess case, because we are getting a `nullptr` when
trying to create a `ScriptedProcessInterface`, we try to discard the
process object, which calls the Process destructor, which in turns
calls the `ScriptedProcess` plugin `IsAlive` method. That method will
fire an assertion if the scripted interface pointer is not allocated.

This patch address that issue by returning early in the Scripted Process
destructor, and not call `Finalize`, if the interface pointer is not valid.

Signed-off-by: Med Ismail Bennani <ismail at bennani.ma>
---
 lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp b/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
index f2a647c1b0bea4c..54b367727913ca7 100644
--- a/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
+++ b/lldb/source/Plugins/Process/scripted/ScriptedProcess.cpp
@@ -130,6 +130,12 @@ ScriptedProcess::ScriptedProcess(lldb::TargetSP target_sp,
 
 ScriptedProcess::~ScriptedProcess() {
   Clear();
+  // If the interface is not valid, we can't call Finalize(). When that happens
+  // it means that the Scripted Process instanciation failed and the
+  // CreateProcess function returns a nullptr, so no one besides this class
+  // should have access to that bogus process object.
+  if (!m_interface_up)
+    return;
   // We need to call finalize on the process before destroying ourselves to
   // make sure all of the broadcaster cleanup goes as planned. If we destruct
   // this class, then Process::~Process() might have problems trying to fully