[Lldb-commits] [lldb] [lldb] Fix trace load hang (PR #187768)

[via lldb-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-lldb

Author: Tom Hewitt (tom-hewitt)

<details>
<summary>Changes</summary>

#<!-- -->179799 removed the `SetPrivateState(eStateStopped)` call in `ProcessTrace::DidAttach()`. This makes the call to `WaitForProcessToStop` hang forever, causing the `trace load` command to hang.

This fix reintroduces the `SetPrivateState` call so a postmortem trace process will "stop" after being loaded, matching the logic used in `Process::LoadCore()`.

---
Full diff: https://github.com/llvm/llvm-project/pull/187768.diff


2 Files Affected:

- (modified) lldb/source/Target/ProcessTrace.cpp (+4) 
- (modified) lldb/unittests/Process/ProcessTraceTest.cpp (+26-1) 


``````````diff
diff --git a/lldb/source/Target/ProcessTrace.cpp b/lldb/source/Target/ProcessTrace.cpp
index 8b7d194aa0767..e2dcd7231b71d 100644
--- a/lldb/source/Target/ProcessTrace.cpp
+++ b/lldb/source/Target/ProcessTrace.cpp
@@ -72,6 +72,10 @@ void ProcessTrace::DidAttach(ArchSpec &process_arch) {
     return;
   }
 
+  // Pretend we stopped so we can show all of the threads
+  // in the trace and explore the final state.
+  SetPrivateState(lldb::eStateStopped);
+
   EventSP event_sp;
   WaitForProcessToStop(std::nullopt, &event_sp, true, listener_sp);
 
diff --git a/lldb/unittests/Process/ProcessTraceTest.cpp b/lldb/unittests/Process/ProcessTraceTest.cpp
index 0bf7ddcbbda21..9134a7f7e3cca 100644
--- a/lldb/unittests/Process/ProcessTraceTest.cpp
+++ b/lldb/unittests/Process/ProcessTraceTest.cpp
@@ -1,4 +1,4 @@
-//===-- ProcessEventDataTest.cpp ------------------------------------------===//
+//===-- ProcessTraceTest.cpp ----------------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -61,3 +61,28 @@ TEST_F(ProcessTraceTest, ConstructorWithNullptrCoreFile) {
 
   ASSERT_NE(process_sp, nullptr);
 }
+
+// Test that a trace process stops after attaching
+TEST_F(ProcessTraceTest, DidAttach) {
+  ArchSpec arch("i386-pc-linux");
+
+  Platform::SetHostPlatform(PlatformLinux::CreateInstance(true, &arch));
+  ASSERT_NE(Platform::GetHostPlatform(), nullptr);
+
+  DebuggerSP debugger_sp = Debugger::CreateInstance();
+  ASSERT_TRUE(debugger_sp);
+
+  TargetSP target_sp = CreateTarget(debugger_sp, arch);
+  ASSERT_TRUE(target_sp);
+
+  ProcessSP process_sp = target_sp->CreateProcess(
+      /*listener*/ nullptr, "trace",
+      /*crash_file*/ nullptr,
+      /*can_connect*/ false);
+
+  ASSERT_NE(process_sp, nullptr);
+
+  process_sp->DidAttach(arch);
+
+  ASSERT_EQ(process_sp->GetState(), lldb::eStateStopped);
+}

``````````

</details>


https://github.com/llvm/llvm-project/pull/187768