[Lldb-commits] [lldb] Reland "[lldb] Clear thread-creation breakpoints in ProcessGDBRemote::Clear (#134397)" (PR #135296)

[Felipe de Azevedo Piovezan via lldb-commits]

https://github.com/felipepiovezan updated https://github.com/llvm/llvm-project/pull/135296

>From b24dc5da70443eb15819c6134ddd38c84f86a5e5 Mon Sep 17 00:00:00 2001
From: Felipe de Azevedo Piovezan <fpiovezan at apple.com>
Date: Wed, 9 Apr 2025 07:38:13 -0700
Subject: [PATCH] Reland "[lldb] Clear thread-creation breakpoints in
 ProcessGDBRemote::Clear (#134397)"

This reapplies commit 232525f06942adb3b9977632e38dcd5f08c0642d.

The original commit triggered a sanitizer failure when `Target` was
destroyed. In `Target::Destroy`, `DeleteCurrentProcess` was called, but
it did not destroy the thread creation breakpoints for the underlying
`ProcessGDBRemote` because `ProcessGDBRemote::Clear` was not called in
that path.

`Target `then proceeded to destroy its breakpoints, which resulted in a
call to the destructor of a `std::vector` containing the breakpoints.
Through a sequence of complicated events, destroying breakpoints caused
the reference count of the underlying `ProcessGDBRemote` to finally
reach zero. This, in turn, called `ProcessGDBRemote::Clear`, which
attempted to destroy the breakpoints. To do that, it would go back into
the Target's vector of breakpoints, which we are in the middle of
destroying.

We solve this by moving the breakpoint deletion into
`Process:DoDestroy`, which is a virtual Process method that will be
called much earlier.
---
 .../Process/gdb-remote/ProcessGDBRemote.cpp   |  9 +++++++++
 .../Process/gdb-remote/ProcessGDBRemote.h     |  3 +++
 .../TestBreakpointsThreadInit.py              | 20 +++++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
index 68360788c96e6..b616e99be83b2 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.cpp
@@ -2571,9 +2571,18 @@ Status ProcessGDBRemote::DoDestroy() {
 
   StopAsyncThread();
   KillDebugserverProcess();
+  RemoveNewThreadBreakpoints();
   return Status();
 }
 
+void ProcessGDBRemote::RemoveNewThreadBreakpoints() {
+  if (m_thread_create_bp_sp) {
+    if (TargetSP target_sp = m_target_wp.lock())
+      target_sp->RemoveBreakpointByID(m_thread_create_bp_sp->GetID());
+    m_thread_create_bp_sp.reset();
+  }
+}
+
 void ProcessGDBRemote::SetLastStopPacket(
     const StringExtractorGDBRemote &response) {
   const bool did_exec =
diff --git a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
index 1cbd1e82b381d..20d7fc0801eb3 100644
--- a/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
+++ b/lldb/source/Plugins/Process/gdb-remote/ProcessGDBRemote.h
@@ -436,6 +436,9 @@ class ProcessGDBRemote : public Process,
                                            lldb::user_id_t break_id,
                                            lldb::user_id_t break_loc_id);
 
+  /// Remove the breakpoints associated with thread creation from the Target.
+  void RemoveNewThreadBreakpoints();
+
   // ContinueDelegate interface
   void HandleAsyncStdout(llvm::StringRef out) override;
   void HandleAsyncMisc(llvm::StringRef data) override;
diff --git a/lldb/test/API/macosx/thread_start_bps/TestBreakpointsThreadInit.py b/lldb/test/API/macosx/thread_start_bps/TestBreakpointsThreadInit.py
index 1c6fd4f91c73e..bf667f6f7d336 100644
--- a/lldb/test/API/macosx/thread_start_bps/TestBreakpointsThreadInit.py
+++ b/lldb/test/API/macosx/thread_start_bps/TestBreakpointsThreadInit.py
@@ -35,3 +35,23 @@ def test_internal_bps_resolved(self):
         for bp in bps:
             num_resolved += bp.GetNumResolvedLocations()
         self.assertGreater(num_resolved, 0)
+
+    @skipUnlessDarwin
+    def test_internal_bps_deleted_on_relaunch(self):
+        self.build()
+
+        source_file = lldb.SBFileSpec("main.c")
+        target, process, thread, bkpt = lldbutil.run_to_source_breakpoint(
+            self, "initial hello", source_file
+        )
+
+        self.runCmd("break list --internal")
+        output = self.res.GetOutput()
+        self.assertEqual(output.count("thread-creation"), 1)
+
+        process.Kill()
+        self.runCmd("run", RUN_SUCCEEDED)
+
+        self.runCmd("break list --internal")
+        output = self.res.GetOutput()
+        self.assertEqual(output.count("thread-creation"), 1)