Add verbose logging support to gdb-remote tests

[labath]

Summary

gdb-remote tests are not able to use the same logging mechanisms as the rest of our tests, and
currently we get no host logs from them, even though the tests themselves have logging
capability. This commit changes that. When user specifies that he would like to log the
gdb-remote channel (--channel gdb-remote argument to dotest.py), we write detailed logs to the
<TEST_ID>-host.log file, just like we would in the case of regular tests. If this argument is not
specified, we only log the serious messages to stderr, which matches the existing behaviour.

[tfiala]

LGTM.

BTW I was planning on re-organizing the lldb-server/debugserver tests sometime in the near future to break them into many different directories and pull off the dsym/dwarf/dwo changes for the many tests where that doesn't matter. It's causing more tests to run and is less concurrent than it could be with our test runner. I'll shoot out a note when that time shows up. (It may still be a while, feel free to tackle if you want to get there sooner.)

[labath]

In D16858#343140, @tfiala wrote:

BTW I was planning on re-organizing the lldb-server/debugserver tests sometime in the near future to break them into many different directories and pull off the dsym/dwarf/dwo changes for the many tests where that doesn't matter.

I think that basically none of these tests rely on debug info, and we can remove the debug info duplication entirely. Unfortunately, the only way right now is to annotate each function with @no_debug_info_test, so I have been waiting until I get a chance to make that decorator work on classes.

That should cut the running time in half, so then you may not even need to split stuff out more...

[tfiala]

In D16858#343895, @labath wrote:

In D16858#343140, @tfiala wrote:

BTW I was planning on re-organizing the lldb-server/debugserver tests sometime in the near future to break them into many different directories and pull off the dsym/dwarf/dwo changes for the many tests where that doesn't matter.

I think that basically none of these tests rely on debug info, and we can remove the debug info duplication entirely. Unfortunately, the only way right now is to annotate each function with @no_debug_info_test, so I have been waiting until I get a chance to make that decorator work on classes.

That should cut the running time in half, so then you may not even need to split stuff out more...

True.

Maybe I'll wait until then. If/when I get to writing more tests in that area, I may reorganize just because it is currently a massive hunk of tests in one file, but if you're going to get rid of the alternatives with a class-level decorator, that definitely will remove the main piece I cared about (namely, the time).

lldb/trunk/packages/Python/lldbsuite/test/tools/lldb-server/gdbremote_testcase.py

 import logging
 
 class GdbRemoteTestCaseBase(TestBase):
 
     _TIMEOUT_SECONDS = 5
 
     _GDBREMOTE_KILL_PACKET = "$k#6b"
 
-    _LOGGING_LEVEL = logging.WARNING
-    # _LOGGING_LEVEL = logging.DEBUG
-
     # Start the inferior separately, attach to the inferior on the stub command line.
     _STARTUP_ATTACH = "attach"
     # Start the inferior separately, start the stub without attaching, allow the test to attach to the inferior however it wants (e.g. $vAttach;pid).
     _STARTUP_ATTACH_MANUALLY = "attach_manually"
     # Start the stub, and launch the inferior with an $A packet via the initial packet stream.
     _STARTUP_LAUNCH = "launch"
 
     # GDB Signal numbers that are not target-specific used for common exceptions
     TARGET_EXC_BAD_ACCESS      = 0x91
     TARGET_EXC_BAD_INSTRUCTION = 0x92
     TARGET_EXC_ARITHMETIC      = 0x93
     TARGET_EXC_EMULATION       = 0x94
     TARGET_EXC_SOFTWARE        = 0x95
     TARGET_EXC_BREAKPOINT      = 0x96
 
+    _verbose_log_handler = None
+    _log_formatter = logging.Formatter(fmt='%(asctime)-15s %(levelname)-8s %(message)s')
+
+    def setUpBaseLogging(self):
+        self.logger = logging.getLogger(__name__)
+
+        if len(self.logger.handlers) > 0:
+            return # We have set up this handler already
+
+        self.logger.propagate = False
+        self.logger.setLevel(logging.DEBUG)
+
+        # log all warnings to stderr
+        handler = logging.StreamHandler()
+        handler.setLevel(logging.WARNING)
+        handler.setFormatter(self._log_formatter)
+        self.logger.addHandler(handler)
+
+
+    def isVerboseLoggingRequested(self):
+        # We will report our detailed logs if the user requested that the "gdb-remote" channel is
+        # logged.
+        return any(("gdb-remote" in channel) for channel in lldbtest_config.channels)
+
     def setUp(self):
         TestBase.setUp(self)
-        FORMAT = '%(asctime)-15s %(levelname)-8s %(message)s'
-        logging.basicConfig(format=FORMAT)
-        self.logger = logging.getLogger(__name__)
-        self.logger.setLevel(self._LOGGING_LEVEL)
+
+        self.setUpBaseLogging()
+
+        if self.isVerboseLoggingRequested():
+            # If requested, full logs go to a log file
+            self._verbose_log_handler = logging.FileHandler(self.log_basename + "-host.log")
+            self._verbose_log_handler.setFormatter(self._log_formatter)
+            self._verbose_log_handler.setLevel(logging.DEBUG)
+            self.logger.addHandler(self._verbose_log_handler)
+
         self.test_sequence = GdbRemoteTestSequence(self.logger)
         self.set_inferior_startup_launch()
         self.port = self.get_next_port()
         self.named_pipe_path = None
         self.named_pipe = None
         self.named_pipe_fd = None
         self.stub_sends_two_stop_notifications_on_kill = False
         if configuration.lldb_platform_url:
             if configuration.lldb_platform_url.startswith('unix-'):
                 url_pattern = '(.+)://\[?(.+?)\]?/.*'
             else:
                 url_pattern = '(.+)://(.+):\d+'
             scheme, host = re.match(url_pattern, configuration.lldb_platform_url).groups()
             if configuration.lldb_platform_name == 'remote-android' and host != 'localhost':
                 self.stub_device = host
                 self.stub_hostname = 'localhost'
             else:
                 self.stub_device = None
                 self.stub_hostname = host
         else:
             self.stub_hostname = "localhost"
 
+    def tearDown(self):
+        self.logger.removeHandler(self._verbose_log_handler)
+        self._verbose_log_handler = None
+        TestBase.tearDown(self)
+
     def get_next_port(self):
         return 12000 + random.randint(0,3999)
 
     def reset_test_sequence(self):
         self.test_sequence = GdbRemoteTestSequence(self.logger)
 
     def create_named_pipe(self):
         # Create a temp dir and name for a pipe.