[NFC][sanitizer] Add Debug utility to print thread history

[vitalybuka]

For #111949

[llvmbot]

@llvm/pr-subscribers-compiler-rt-sanitizer

Author: Vitaly Buka (vitalybuka)

Changes

---

Full diff: https://github.com/llvm/llvm-project/pull/111948.diff

3 Files Affected:

• (modified) compiler-rt/lib/sanitizer_common/CMakeLists.txt (+1)
• (added) compiler-rt/lib/sanitizer_common/sanitizer_thread_history.cpp (+73)
• (added) compiler-rt/lib/sanitizer_common/sanitizer_thread_history.h (+24)

diff --git a/compiler-rt/lib/sanitizer_common/CMakeLists.txt b/compiler-rt/lib/sanitizer_common/CMakeLists.txt
index 556a64f3017488..09391e4f5f3704 100644
--- a/compiler-rt/lib/sanitizer_common/CMakeLists.txt
+++ b/compiler-rt/lib/sanitizer_common/CMakeLists.txt
@@ -94,6 +94,7 @@ set(SANITIZER_SYMBOLIZER_SOURCES
   sanitizer_symbolizer_report.cpp
   sanitizer_symbolizer_report_fuchsia.cpp
   sanitizer_symbolizer_win.cpp
+  sanitizer_thread_history.cpp
   sanitizer_unwind_linux_libcdep.cpp
   sanitizer_unwind_fuchsia.cpp
   sanitizer_unwind_win.cpp
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_thread_history.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_thread_history.cpp
new file mode 100644
index 00000000000000..32a6ab1b39d3f7
--- /dev/null
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_thread_history.cpp
@@ -0,0 +1,73 @@
+//===-- sanitizer_thread_history.cpp --------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "sanitizer_thread_history.h"
+
+#include "sanitizer_stackdepot.h"
+namespace __sanitizer {
+
+void PrintThreadHistory(ThreadRegistry &registry, InternalScopedString &out) {
+  ThreadRegistryLock l(&registry);
+  // Stack traces are largest part of printout and they offten the same for
+  // multiple threads, so we will deduplicate them.
+  InternalMmapVector<const ThreadContextBase *> stacks;
+
+  registry.RunCallbackForEachThreadLocked(
+      [](ThreadContextBase *context, void *arg) {
+        static_cast<decltype(&stacks)>(arg)->push_back(context);
+      },
+      &stacks);
+
+  Sort(stacks.data(), stacks.size(),
+       [](const ThreadContextBase *a, const ThreadContextBase *b) {
+         if (a->stack_id < b->stack_id)
+           return true;
+         if (a->stack_id > b->stack_id)
+           return false;
+         return a->tid < b->tid;
+       });
+
+  auto describe_thread = [&](const ThreadContextBase *context) {
+    if (!context) {
+      out.Append("T-1");
+      return;
+    }
+    out.AppendF("T%llu/%llu", context->unique_id, context->os_id);
+    if (internal_strlen(context->name))
+      out.AppendF(" (%s)", context->name);
+  };
+
+  auto get_parent =
+      [&](const ThreadContextBase *context) -> const ThreadContextBase * {
+    if (!context)
+      return nullptr;
+    ThreadContextBase *parent = registry.GetThreadLocked(context->parent_tid);
+    if (!parent)
+      return nullptr;
+    if (parent->unique_id >= context->unique_id)
+      return nullptr;
+    return parent;
+  };
+
+  u32 stack_id = 0;
+  for (const ThreadContextBase *context : stacks) {
+    if (stack_id != context->stack_id) {
+      StackDepotGet(stack_id).PrintTo(&out);
+      stack_id = context->stack_id;
+    }
+    out.Append("Thread ");
+    describe_thread(context);
+    out.Append(" was created by ");
+    describe_thread(get_parent(context));
+    out.Append("\n");
+  }
+  if (!stacks.empty())
+    StackDepotGet(stack_id).PrintTo(&out);
+}
+
+}  // namespace __sanitizer
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_thread_history.h b/compiler-rt/lib/sanitizer_common/sanitizer_thread_history.h
new file mode 100644
index 00000000000000..2995f6015fe50e
--- /dev/null
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_thread_history.h
@@ -0,0 +1,24 @@
+//===-- sanitizer_thread_history.h ------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Utility to print thread histroy from ThreadRegistry.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef SANITIZER_THREAD_HISTORY_H
+#define SANITIZER_THREAD_HISTORY_H
+
+#include "sanitizer_thread_registry.h"
+
+namespace __sanitizer {
+
+void PrintThreadHistory(ThreadRegistry& registry, InternalScopedString& out);
+
+}  // namespace __sanitizer
+
+#endif  // SANITIZER_THREAD_HISTORY_H

[Enna1]

Will uses of __asan::DescribeThread be replaced with __sanitizer::PrintThreadHistory introduced in this patch?

[vitalybuka]

Will uses of __asan::DescribeThread be replaced with __sanitizer::PrintThreadHistory introduced in this patch?

I don't have plans to do so any time soon.

Long term I am not sure. WDYT?

DescribeThread prints, 1-thread + 1-stack and OK for existing application
PrintThreadHistory deduplicate stacks.

[Enna1]

Will uses of __asan::DescribeThread be replaced with __sanitizer::PrintThreadHistory introduced in this patch?

I don't have plans to do so any time soon.

Long term I am not sure. WDYT?

DescribeThread prints, 1-thread + 1-stack and OK for existing application PrintThreadHistory deduplicate stacks.

Currently, only Asan and MemProf "share" the same implementation of DescribeThread, and there is no use of DescribeThread in MemProf, not sure if it's worth extracting DescribeThread into sanitizer_thread_history.cpp.

[mgorny]

FYI, this commit seems to have introduced test failures for me, but they seem to be incidental; I've filed #112399 about it.