Add a benchmark for measuring the response time of the 'frame variable' command.

Example (start the lldb inferior, break at the Driver::MainLoop() function, and
issue 'frame variable'):

 $ ./dotest.py -v +b -x '-F Driver::MainLoop()' -n -p TestFrameVariableResponse.py
----------------------------------------------------------------------
Collected 1 test

1: test_startup_delay (TestFrameVariableResponse.FrameVariableResponseBench)
   Test response time for the 'frame variable' command. ... 
lldb frame variable benchmark: Avg: 1.636897 (Laps: 20, Total Elapsed Time: 32.737944)
ok

----------------------------------------------------------------------
Ran 1 test in 65.105s

OK

llvm-svn: 142678

lldb/test/benchmarks/frame_variable/TestFrameVariableResponse.py

@@ -0,0 +1,79 @@
+"""Test lldb's response time for 'frame variable' command."""
+
+import os, sys
+import unittest2
+import lldb
+import pexpect
+from lldbbench import *
+
+class FrameVariableResponseBench(BenchBase):
+
+    mydir = os.path.join("benchmarks", "frame_variable")
+
+    def setUp(self):
+        BenchBase.setUp(self)
+        if lldb.bmExecutable:
+            self.exe = lldb.bmExecutable
+        else:
+            self.exe = self.lldbHere
+        if lldb.bmBreakpointSpec:
+            self.break_spec = lldb.bmBreakpointSpec
+        else:
+            self.break_spec = '-n main'
+
+        self.count = lldb.bmIterationCount
+        if self.count <= 0:
+            self.count = 20
+
+    @benchmarks_test
+    def test_startup_delay(self):
+        """Test response time for the 'frame variable' command."""
+        print
+        self.run_frame_variable_bench(self.exe, self.break_spec, self.count)
+        print "lldb frame variable benchmark:", self.stopwatch
+
+    def run_frame_variable_bench(self, exe, break_spec, count):
+        # Set self.child_prompt, which is "(lldb) ".
+        self.child_prompt = '(lldb) '
+        prompt = self.child_prompt
+
+        # Reset the stopwatchs now.
+        self.stopwatch.reset()
+        for i in range(count):
+            # So that the child gets torn down after the test.
+            self.child = pexpect.spawn('%s %s %s' % (self.lldbHere, self.lldbOption, exe))
+            child = self.child
+
+            # Turn on logging for what the child sends back.
+            if self.TraceOn():
+                child.logfile_read = sys.stdout
+
+            # Set our breakpoint.
+            child.sendline('breakpoint set %s' % break_spec)
+            child.expect_exact(prompt)
+
+            # Run the target and expect it to be stopped due to breakpoint.
+            child.sendline('run') # Aka 'process launch'.
+            child.expect_exact(prompt)
+        
+            with self.stopwatch:
+                # Measure the 'frame variable' response time.
+                child.sendline('frame variable')
+                child.expect_exact(prompt)
+
+            child.sendline('quit')
+            try:
+                self.child.expect(pexpect.EOF)
+            except:
+                pass
+
+        # The test is about to end and if we come to here, the child process has
+        # been terminated.  Mark it so.
+        self.child = None
+
+
+if __name__ == '__main__':
+    import atexit
+    lldb.SBDebugger.Initialize()
+    atexit.register(lambda: lldb.SBDebugger.Terminate())
+    unittest2.main()