Fix Python binding generation build step on Windows

[enlight]

Summary

If Python is installed to a location that contains spaces (e.g. "C:\Program Files\Python3") then the build fails while attempting to run the modify-python-lldb.py script because the path to the Python executable is not double-quoted before being passed to the shell. The fix consists of letting Python handle the formatting of the command line, since subprocess.Popen() is perfectly capable of handling paths containing spaces if it's given the command and arguments as a list instead of a single pre-formatted string.

This fixed the build for me on Windows 10, and didn't seem to break the build on Ubuntu 14.10.

[enlight]

@zturner Are you good with this going in?

[ldrumm]

lldb/trunk/scripts/Python/prepare_binding_Python.py

273 ↗

(On Diff #74472)

Seeing as we're logging a failure to call our command here, perhaps using the repr format string type:

logging.error("failed to run %r: %s", command, script_stderr) would give the exact invocation of the failed command, and means we're not precomputing a "pretty" - possibly false representation of the command line.

We can the get rid of command_line = " ".join(command) as it's no longer needed

276 ↗

(On Diff #74472)

Same here.

[amccarth]

lldb/trunk/scripts/Python/prepare_binding_Python.py

273 ↗

(On Diff #74472)

When an error is logged, it's handy to be able to copy and paste the command line in order to reproduce/debug the failure. In that case, the repr format isn't particularly useful. I'd rather have the "pretty" format, even if I have to fix a few quoting problems.

scripts/Python/prepare_binding_Python.py

def run_python_script(script_and_args):
     """Runs a python script, logging appropriately.
 
     If the command returns anything non-zero, it is registered as
     an error and exits the program.
 
     @param script_and_args the python script to execute, along with
     the command line arguments to pass to it.
     """
-    command_line = "%s %s" % (sys.executable, script_and_args)
-    process = subprocess.Popen(command_line, shell=True)
+    command = [sys.executable] + script_and_args
+    command_line = " ".join(command)
+    process = subprocess.Popen(command, shell=False)
     script_stdout, script_stderr = process.communicate()
     return_code = process.returncode
     if return_code != 0:
         logging.error("failed to run '%s': %s", command_line, script_stderr)
         sys.exit(return_code)
     else:
         logging.info("ran script '%s'", command_line)
         if script_stdout is not None:
script_path = os.path.normcase(
             "scripts",
             "Python",
             "modify-python-lldb.py"))
 
     if not os.path.exists(script_path):
         logging.error("failed to find python script: '%s'", script_path)
         sys.exit(-11)
 
-    script_invocation = "%s %s" % (script_path, config_build_dir)
-    run_python_script(script_invocation)
+    run_python_script([script_path, config_build_dir])
 
 
 def get_python_module_path(options):
     """Returns the location where the lldb Python module should be placed.
 
     @param options dictionary of options parsed from the command line.
 
     @return the directory where the lldb module should be placed.