lldbutil: add a retry mechanism for the ios simulator

[aprantl]

Summary

We've been seeing this failure on green dragon when the system is under high load. Unfortunately this is outside of LLDB's control.

[JDevlieghere]

lldb/packages/Python/lldbsuite/test/lldbutil.py

826

Why is this necessary? Is there an error case where error.GetCString is not a python string? If so we should probably factor this out in a function and do the if sys.version_info.major == 2: str.decode('utf-8', 'replace') trick instead because otherwise the retry won't kick in.

[aprantl]

lldb/packages/Python/lldbsuite/test/lldbutil.py

826

It may be None. So I guess we could write and error.GetCString()? I just didn't want to crash on unexpected input.

[aprantl]

Address review feedback

[JDevlieghere]

LGTM with the comments addressed. Thanks for fixing this!

lldb/packages/Python/lldbsuite/test/lldbutil.py

824

Nit: can we make this a global constant like SIMULATOR_RETRY?

826

Got it, yeah then that should be sufficient.

lldb/packages/Python/lldbsuite/test/lldbutil.py

 # Third-party modules
 from six import StringIO as SixStringIO
 import six
 
 # LLDB modules
 import lldb
 from . import lldbtest_config
 
+# How often failed simulator process launches are retried.
+SIMULATOR_RETRY = 3
 
 # ===================================================
 # Utilities for locating/checking executable programs
 # ===================================================
 
 def is_exe(fpath):
     """Returns True if fpath is an executable."""
     return os.path.isfile(fpath) and os.access(fpath, os.X_OK)
def run_to_breakpoint_do_run(test, target, bkpt, launch_info = None,
 
     if extra_images:
         environ = test.registerSharedLibrariesWithTarget(target, extra_images)
         launch_info.SetEnvironmentEntries(environ, True)
 
     error = lldb.SBError()
     process = target.Launch(launch_info, error)
 
+    # Unfortunate workaround for the iPhone simulator.
+    retry = SIMULATOR_RETRY
+    while (retry and error.Fail() and error.GetCString() and
+           "Unable to boot the Simulator" in error.GetCString()):
+        retry -= 1
+        print("** Simulator is unresponsive. Retrying %d more time(s)"%retry)
+        import time
+        time.sleep(60)
+        error = lldb.SBError()
+        process = target.Launch(launch_info, error)
+
     test.assertTrue(process,
-                    "Could not create a valid process for %s: %s"%(target.GetExecutable().GetFilename(),
-                    error.GetCString()))
+                    "Could not create a valid process for %s: %s" %
+                    (target.GetExecutable().GetFilename(), error.GetCString()))
     test.assertFalse(error.Fail(),
                      "Process launch failed: %s" % (error.GetCString()))
 
     test.assertEqual(process.GetState(), lldb.eStateStopped)
 
     # Frame #0 should be at our breakpoint.
     threads = get_threads_stopped_at_breakpoint(
                 process, bkpt)