win: Gather memory information

util/win/process_info_test_child.cc

Index: util/win/process_info_test_child.cc
diff --git a/util/win/process_info_test_child.cc b/util/win/process_info_test_child.cc
index a0cf5c403a5f2f3963f4a4f2a87d50a54eaeb33e..c587f5b852de80a609f51cbdec10663321ddca79 100644
--- a/util/win/process_info_test_child.cc
+++ b/util/win/process_info_test_child.cc
@@ -12,19 +12,20 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <intrin.h>
 #include <stdlib.h>
+#include <stdint.h>
 #include <wchar.h>
 #include <windows.h>
 
 // A simple binary to be loaded and inspected by ProcessInfo.
 int wmain(int argc, wchar_t** argv) {
-  if (argc != 3)
+  if (argc != 2)
     abort();
 
-  // Get handles to the events we use to communicate with our parent.
-  HANDLE started_event = CreateEvent(nullptr, true, false, argv[1]);
-  HANDLE done_event = CreateEvent(nullptr, true, false, argv[2]);
-  if (!started_event || !done_event)
+  // Get a handle to the event we use to communicate with our parent.
+  HANDLE done_event = CreateEvent(nullptr, true, false, argv[1]);
+  if (!done_event)
     abort();
 
   // Load an unusual module (that we don't depend upon) so we can do an
@@ -32,14 +33,22 @@ int wmain(int argc, wchar_t** argv) {
   if (!LoadLibrary(L"lz32.dll"))
     abort();
 
-  if (!SetEvent(started_event))
+  HANDLE out = GetStdHandle(STD_OUTPUT_HANDLE);
+  if (out == INVALID_HANDLE_VALUE)
     abort();
+  // We just want any valid address that's known to be code.
+  uint64_t code_address = reinterpret_cast<uint64_t>(_ReturnAddress());
+  DWORD bytes_written;
+  if (!WriteFile(
+          out, &code_address, sizeof(code_address), &bytes_written, nullptr) ||
+      bytes_written != sizeof(code_address)) {
+    abort();
+  }
 
   if (WaitForSingleObject(done_event, INFINITE) != WAIT_OBJECT_0)
     abort();
 
   CloseHandle(done_event);
-  CloseHandle(started_event);
 
   return EXIT_SUCCESS;
 }