[compiler-rt] r347368 - [XRay] Add a test for re-initialising FDR mode (NFC)

[Dean Michael Berris via llvm-commits]

Author: dberris
Date: Tue Nov 20 16:30:26 2018
New Revision: 347368

URL: http://llvm.org/viewvc/llvm-project?rev=347368&view=rev
Log:
[XRay] Add a test for re-initialising FDR mode (NFC)

This change adds an end-to-end test that ensures FDR mode can be
re-initialised safely in the face of multiple threads being traced.

Added:
    compiler-rt/trunk/test/xray/TestCases/Posix/fdr-reinit.cc

Added: compiler-rt/trunk/test/xray/TestCases/Posix/fdr-reinit.cc
URL: http://llvm.org/viewvc/llvm-project/compiler-rt/trunk/test/xray/TestCases/Posix/fdr-reinit.cc?rev=347368&view=auto
==============================================================================
--- compiler-rt/trunk/test/xray/TestCases/Posix/fdr-reinit.cc (added)
+++ compiler-rt/trunk/test/xray/TestCases/Posix/fdr-reinit.cc Tue Nov 20 16:30:26 2018
@@ -0,0 +1,72 @@
+// RUN: %clangxx_xray -g -std=c++11 %s -o %t
+// RUN: rm xray-log.fdr-reinit* || true
+// RUN: XRAY_OPTIONS="verbosity=1" %run %t
+// RUN: rm xray-log.fdr-reinit* || true
+#include "xray/xray_log_interface.h"
+#include <cassert>
+#include <cstddef>
+#include <thread>
+
+volatile uint64_t var = 0;
+
+std::atomic_flag keep_going = ATOMIC_FLAG_INIT;
+
+[[clang::xray_always_instrument]] void __attribute__((noinline)) func() {
+  ++var;
+}
+
+int main(int argc, char *argv[]) {
+  // Start a thread that will just keep calling the function, to spam calls to
+  // the function call handler.
+  keep_going.test_and_set(std::memory_order_acquire);
+  std::thread t([] {
+    while (keep_going.test_and_set(std::memory_order_acquire))
+      func();
+  });
+
+  static constexpr char kConfig[] =
+      "buffer_size=1024:buffer_max=10:no_file_flush=true";
+
+  // Then we initialize the FDR mode implementation.
+  assert(__xray_log_select_mode("xray-fdr") ==
+         XRayLogRegisterStatus::XRAY_REGISTRATION_OK);
+  auto init_status = __xray_log_init_mode("xray-fdr", kConfig);
+  assert(init_status == XRayLogInitStatus::XRAY_LOG_INITIALIZED);
+
+  // Now we patch the instrumentation points.
+  __xray_patch();
+
+  // Spin for a bit, calling func() enough times.
+  for (auto i = 0; i < 1 << 20; ++i)
+    func();
+
+  // Then immediately finalize the implementation.
+  auto finalize_status = __xray_log_finalize();
+  assert(finalize_status == XRayLogInitStatus::XRAY_LOG_FINALIZED);
+
+  // Once we're here, we should then flush.
+  auto flush_status = __xray_log_flushLog();
+  assert(flush_status == XRayLogFlushStatus::XRAY_LOG_FLUSHED);
+
+  // Without doing anything else, we should re-initialize.
+  init_status = __xray_log_init_mode("xray-fdr", kConfig);
+  assert(init_status == XRayLogInitStatus::XRAY_LOG_INITIALIZED);
+
+  // Then we spin for a bit again calling func() enough times.
+  for (auto i = 0; i < 1 << 20; ++i)
+    func();
+
+  // Then immediately finalize the implementation.
+  finalize_status = __xray_log_finalize();
+  assert(finalize_status == XRayLogInitStatus::XRAY_LOG_FINALIZED);
+
+  // Once we're here, we should then flush.
+  flush_status = __xray_log_flushLog();
+  assert(flush_status == XRayLogFlushStatus::XRAY_LOG_FLUSHED);
+
+  // Finally, we should signal the sibling thread to stop.
+  keep_going.clear(std::memory_order_release);
+
+  // Then join.
+  t.join();
+}