python,scons: Move readCommand and compareVersions into site_scons.

These functions are only used by scons, so it makes sense to move them
to site_scons/gem5_scons/util.py.

Change-Id: If2b3995f208cb71adf3c59aac4eabe378c47f94f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/41599
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/python/m5/util/__init__.py

@@ -41,8 +41,6 @@ import os
 import re
 import sys
 
-from itertools import zip_longest
-
 from . import convert
 from . import jobfile
 
@@ -112,31 +110,6 @@ def applyOrMap(objOrSeq, meth, *args, **kwargs):
     else:
         return [applyMethod(o, meth, *args, **kwargs) for o in objOrSeq]
 
-def compareVersions(v1, v2):
-    """helper function: compare arrays or strings of version numbers.
-    E.g., compare_version((1,3,25), (1,4,1)')
-    returns -1, 0, 1 if v1 is <, ==, > v2
-    """
-    def make_version_list(v):
-        if isinstance(v, (list,tuple)):
-            return v
-        elif isinstance(v, str):
-            return list(map(lambda x: int(re.match('\d+', x).group()),
-                            v.split('.')))
-        else:
-            raise TypeError()
-
-    v1 = make_version_list(v1)
-    v2 = make_version_list(v2)
-
-    # Compare corresponding elements of lists
-    # The shorter list is filled with 0 till the lists have the same length
-    for n1,n2 in zip_longest(v1, v2, fillvalue=0):
-        if n1 < n2: return -1
-        if n1 > n2: return  1
-
-    return 0
-
 def crossproduct(items):
     if len(items) == 1:
         for i in items[0]:
@@ -173,38 +146,6 @@ def printList(items, indent=4):
             line += item
             print(line)
 
-def readCommand(cmd, **kwargs):
-    """
-    run the command cmd, read the results and return them
-    this is sorta like `cmd` in shell
-
-    :param cmd: command to run with Popen
-    :type cmd: string, list
-    :returns: command stdout
-    :rtype: string
-    """
-    from subprocess import Popen, PIPE, STDOUT
-
-    if isinstance(cmd, str):
-        cmd = cmd.split()
-
-    no_exception = 'exception' in kwargs
-    exception = kwargs.pop('exception', None)
-
-    kwargs.setdefault('shell', False)
-    kwargs.setdefault('stdout', PIPE)
-    kwargs.setdefault('stderr', STDOUT)
-    kwargs.setdefault('close_fds', True)
-    try:
-        subp = Popen(cmd, **kwargs)
-    except Exception as e:
-        if no_exception:
-            return -1, exception
-        raise
-
-    output = subp.communicate()[0].decode('utf-8')
-    return output
-
 def makeDir(path):
     """Make a directory if it doesn't exist.  If the path does exist,
     ensure that it is a directory"""