src/os/windows/vm/os_windows.cpp

rev 4773 : 8005849: JEP 167: Event-Based JVM Tracing
Reviewed-by: acorn, coleenp, sla
Contributed-by: Karen Kinnear <karen.kinnear@oracle.com>, Bengt Rutisson <bengt.rutisson@oracle.com>, Calvin Cheung <calvin.cheung@oracle.com>, Erik Gahlin <erik.gahlin@oracle.com>, Erik Helin <erik.helin@oracle.com>, Jesper Wilhelmsson <jesper.wilhelmsson@oracle.com>, Keith McGuigan <keith.mcguigan@oracle.com>, Mattias Tobiasson <mattias.tobiasson@oracle.com>, Markus Gronlund <markus.gronlund@oracle.com>, Mikael Auno <mikael.auno@oracle.com>, Nils Eliasson <nils.eliasson@oracle.com>, Nils Loodin <nils.loodin@oracle.com>, Rickard Backman <rickard.backman@oracle.com>, Staffan Larsen <staffan.larsen@oracle.com>, Stefan Karlsson <stefan.karlsson@oracle.com>, Yekaterina Kantserova <yekaterina.kantserova@oracle.com>

@@ -5040,10 +5040,75 @@
 int os::set_sock_opt(int fd, int level, int optname,
                      const char* optval, socklen_t optlen) {
   return ::setsockopt(fd, level, optname, optval, optlen);
 }
 
+// WINDOWS CONTEXT Flags for THREAD_SAMPLING
+#if defined(IA32)
+#  define sampling_context_flags (CONTEXT_FULL | CONTEXT_FLOATING_POINT | CONTEXT_EXTENDED_REGISTERS)
+#elif defined (AMD64)
+#  define sampling_context_flags (CONTEXT_FULL | CONTEXT_FLOATING_POINT)
+#endif
+
+// returns true if thread could be suspended,
+// false otherwise
+static bool do_suspend(HANDLE* h) {
+  if (h != NULL) {
+    if (SuspendThread(*h) != ~0) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// resume the thread
+// calling resume on an active thread is a no-op
+static void do_resume(HANDLE* h) {
+  if (h != NULL) {
+    ResumeThread(*h);
+  }
+}
+
+// retrieve a suspend/resume context capable handle
+// from the tid. Caller validates handle return value.
+void get_thread_handle_for_extended_context(HANDLE* h, OSThread::thread_id_t tid) {
+  if (h != NULL) {
+    *h = OpenThread(THREAD_SUSPEND_RESUME | THREAD_GET_CONTEXT | THREAD_QUERY_INFORMATION, FALSE, tid);
+  }
+}
+
+//
+// Thread sampling implementation
+//
+void os::SuspendedThreadTask::internal_do_task() {
+  CONTEXT    ctxt;
+  HANDLE     h = NULL;
+
+  // get context capable handle for thread
+  get_thread_handle_for_extended_context(&h, _thread->osthread()->thread_id());
+
+  // sanity
+  if (h == NULL || h == INVALID_HANDLE_VALUE) {
+    return;
+  }
+
+  // suspend the thread
+  if (do_suspend(&h)) {
+    ctxt.ContextFlags = sampling_context_flags;
+    // get thread context
+    GetThreadContext(h, &ctxt);
+    SuspendedThreadTaskContext context(_thread, &ctxt);
+    // pass context to Thread Sampling impl
+    do_task(context);
+    // resume thread
+    do_resume(&h);
+  }
+
+  // close handle
+  CloseHandle(h);
+}
+
 
 // Kernel32 API
 typedef SIZE_T (WINAPI* GetLargePageMinimum_Fn)(void);
 typedef LPVOID (WINAPI *VirtualAllocExNuma_Fn) (HANDLE, LPVOID, SIZE_T, DWORD, DWORD, DWORD);
 typedef BOOL (WINAPI *GetNumaHighestNodeNumber_Fn) (PULONG);