util/regress: make default action a more thorough regression

Changed the --variants option to --test-variants and added a new
--compile-variants option for variants that are only compiled
(not tested).  The former still defaults to 'opt' and the latter
defaults to 'debug,fast'.

Also changed the behavior when no tests are specified from just
compiling to running the 'quick' tests.

As a result, a plain 'util/regress' invocation will now compile
(but not test) the debug and fast builds, and compile and run the
quick regressions on the opt build.  This should be the default
set of tests that are run before committing.  Since the nightly
regressions use this same script, this will also be the new
nightly regression behavior.

Test-only regressions can still be done by setting --compile=''.
Compile-only regressions can be done by setting --test=''.

util/regress

@@ -37,10 +37,9 @@ progname = os.path.basename(sys.argv[0])
 
 optparser = optparse.OptionParser()
 add_option = optparser.add_option
-add_option('-v', '--verbose', dest='verbose', action='store_true',
-           default=False,
+add_option('-v', '--verbose', action='store_true', default=False,
            help='echo commands before executing')
-add_option('--builds', dest='builds',
+add_option('--builds',
            default='ALPHA_SE,ALPHA_SE_MOESI_hammer,' \
            'ALPHA_SE_MESI_CMP_directory,'  \
            'ALPHA_SE_MOESI_CMP_directory,' \
@@ -52,15 +51,21 @@ add_option('--builds', dest='builds',
            'X86_SE,X86_FS,' \
            'ARM_SE,ARM_FS',
            help="comma-separated build targets to test (default: '%default')")
-add_option('--variants', dest='variants', default='opt',
-           help="comma-separated build variants to test (default: '%default')")
-add_option('--scons-opts', dest='scons_opts', default='', metavar='OPTS',
+add_option('--test-variants', default='opt',
+           help="comma-separated build variants to test (default: '%default')"\
+           ", set to '' for none")
+add_option('--compile-variants', default='debug,fast',
+           help="comma-separated build variants to compile only (not test) " \
+           "(default: '%default'), set to '' for none", metavar='VARIANTS')
+add_option('--scons-opts', default='', metavar='OPTS',
            help='scons options')
-add_option('-j', '--jobs', type='int', default=1,
-           help='number of parallel jobs to use')
+add_option('-j', '--jobs', type='int', default=1, metavar='N',
+           help='number of parallel jobs to use (0 to use all cores)')
 add_option('-k', '--keep-going', action='store_true',
            help='keep going after errors')
-add_option('-D', '--build-dir', default='',
+add_option('--update-ref', action='store_true',
+           help='update reference outputs')
+add_option('-D', '--build-dir', default='', metavar='DIR',
            help='build directory location')
 add_option('-n', "--no-exec", default=False, action='store_true',
            help="don't actually invoke scons, just echo SCons command line")
@@ -68,9 +73,17 @@ add_option('-n', "--no-exec", default=False, action='store_true',
 (options, tests) = optparser.parse_args()
 
 
+# split a comma-separated list, but return an empty list if given the
+# empty string
+def split_if_nonempty(s):
+    if not s:
+        return []
+    return s.split(',')
+
 # split list options on ',' to get Python lists
-builds = options.builds.split(',')
-variants = options.variants.split(',')
+builds = split_if_nonempty(options.builds)
+test_variants = split_if_nonempty(options.test_variants)
+compile_variants = split_if_nonempty(options.compile_variants)
 
 options.build_dir = os.path.join(options.build_dir, 'build')
 
@@ -91,29 +104,32 @@ def system(cmd):
         print >>sys.stderr, "When attemping to execute: %s" % cmd
         sys.exit(1)
 
-# Quote string s so it can be passed as a shell arg
-def shellquote(s):
-    if ' ' in s:
-        s = "'%s'" % s
-    return s
+targets = []
 
+# start with compile-only targets, if any
+if compile_variants:
+    targets += ['%s/%s/m5.%s' % (options.build_dir, build, variant)
+                for variant in compile_variants
+                for build in builds]
+
+# By default run the 'quick' tests
 if not tests:
-    print "No tests specified, just building binaries."
-    targets = ['%s/%s/m5.%s' % (options.build_dir, build, variant)
+    tests = ['quick']
+
+# set up test targets for scons
+if 'all' in tests:
+    targets += ['%s/%s/tests/%s' % (options.build_dir, build, variant)
                 for build in builds
-               for variant in variants]
-elif 'all' in tests:
-    targets = ['%s/%s/tests/%s' % (options.build_dir, build, variant)
-               for build in builds
-               for variant in variants]
+                for variant in test_variants]
 else:
-    # Ugly! Since we don't have any quick SPARC_FS tests remove the SPARC_FS target
-    # If we ever get a quick SPARC_FS test, this code should be removed
+    # Ugly! Since we don't have any quick SPARC_FS tests remove the
+    # SPARC_FS target If we ever get a quick SPARC_FS test, this code
+    # should be removed
     if 'quick' in tests and 'SPARC_FS' in builds:
         builds.remove('SPARC_FS')
-    targets = ['%s/%s/tests/%s/%s' % (options.build_dir, build, variant, test)
+    targets += ['%s/%s/tests/%s/%s' % (options.build_dir, build, variant, test)
                 for build in builds
-               for variant in variants
+                for variant in test_variants
                 for test in tests]
 
 def cpu_count():
@@ -137,6 +153,8 @@ if options.jobs != 1:
     scons_opts += ' -j %d' % options.jobs
 if options.keep_going:
     scons_opts += ' -k'
+if options.update_ref:
+    scons_opts += ' --update-ref'
 
 cmd = 'scons --ignore-style %s %s' % (scons_opts, ' '.join(targets))
 if options.no_exec: