[PATCH] Add support for lldb remote test

[Ying Chen]

================
Comment at: buildbot/osuosl/master/config/builders.py:724
@@ -723,1 +723,3 @@
                     test_compilers=['clang', 'totclang', 'gcc4.8.2'],
+                    remote_ip="173.255.116.181",
+                    remote_dir="/lldb-buildbot/remotetest",
----------------
chaoren wrote:
> Does this have to be hardcoded? You should probably use a hostname instead if it must be hardcoded.
The remote test instance was created with static ip, so this should be fine. It was not easy to debug with hostname, because gce instance cannot be reached by hostname from workstation(maybe there is some way that i don't know about).
But hostname could be used from one gce to another. 
I will find if hostname works.

================
Comment at: zorg/buildbot/builders/LLDBBuilder.py:266
@@ +265,3 @@
+    f.addStep(ShellCommand(name="launch lldb-server",
+                           command="ssh %s screen -d -m %s/lldb-server platform --listen *:5432 --server" % (remote_ip, remote_dir),
+                           description="launch lldb-server on remote host",
----------------
chaoren wrote:
> > screen -d -m
> 
> Why not `ssh -f`?
> 
> > --listen *:5432
> 
> Is this remote machine accessible from anywhere besides the build machine? If you know the hostname of the build machine, you should probably use that instead of `*`. Also, must the port be hardcoded?
"ssh -f" doesn't detach the process from current shell, the process is still running in the background when using "ssh -f". Since buildbot will wait for current process exit to continue next step, so use "screen -d -m"  to return immediately.

Yes, it's accessible from any machine for authorized users. 
Same as above, I will find if hostname works.
Port could be specified by builder.

http://reviews.llvm.org/D8711

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/