Add `%match_min_os_deployment_version_to_target` lit substitution.

[delcypher]

Summary

This substitution expands to the clang flag that sets the minimum
deployment target OS version to the version of the OS that the
testing target uses.

This requires querying the test target at testing time
for the OS version of the target. We assume that
%run sw_vers -productVersion can obtain this.

For the iOS simulator the sw_vers command does not exist
so we emulate a subset of the command's capabilities by
probing the environment of the simulator.

The motivation here is that bbde056b88 made all sanitizer tests
run with the lowest deployment target possible. This means we
no longer test newer deployment targets. This patch will make it
possible to write lit tests that target newer deployment targets.

rdar://problem/57127911

[delcypher]

@yln ping.

[delcypher]

@yln @kubamracek Ping.

compiler-rt/test/lit.common.cfg.py

else:
       # this "feature", we can pass the test on newer OS X versions and other
       # platforms.
       config.available_features.add('osx-no-ld64-live_support')
   except:
     pass
 
   config.darwin_osx_version = osx_version
 
+  # Get Target OS version
+  get_os_cmd = []
+  run_wrapper = filter(lambda s: s[0] == '%run', config.substitutions)[0][1]
+  assert isinstance(run_wrapper, str)
+  if run_wrapper != "":
+    get_os_cmd.append(run_wrapper)
+  get_os_cmd.extend(['sw_vers', '-productVersion'])
+  apple_target_os_version_output = subprocess.check_output(get_os_cmd)
+  apple_target_os_tuple = None
+  for line in apple_target_os_version_output.split('\n'):
+    m = re.match(r'^(?P<major>\d+)\.(?P<minor>\d+)(\.(?P<patch>\d+))?$', line)
+    if m:
+      apple_target_os_major_version = int(m.group('major'))
+      apple_target_os_minor_version = int(m.group('minor'))
+      apple_target_os_patch_version = 0
+      if m.group('patch'):
+        apple_target_os_patch_version = int(m.group('patch'))
+      apple_target_os_tuple = (
+        apple_target_os_major_version,
+        apple_target_os_minor_version,
+        apple_target_os_patch_version
+      )
+      break
+  if not apple_target_os_tuple:
+    lit_config.fatal('Failed to determine OS version of {} target'.format(
+      config.apple_platform)
+    )
+  lit_config.note(
+    'Target Apple platform {} has version {}'.format(
+      config.apple_platform,
+      apple_target_os_tuple)
+  )
+  # Create substitution for minimum deployment target matching target
+  if config.apple_platform == 'osx':
+    min_os_version_deployment_flag = '-mmacosx-version-min'
+  elif config.apple_platform == 'ios':
+    min_os_version_deployment_flag = '-miphoneos-version-min'
+  elif config.apple_platform == 'iossim':
+    min_os_version_deployment_flag = '-mios-simulator-version-min'
+  elif config.apple_platform == 'watchos':
+    min_os_version_deployment_flag = '-mwatchos-version-min'
+  elif config.apple_platform == 'watchossim':
+    min_os_version_deployment_flag = '-mwatchos-simulator-version-min'
+  elif config.apple_platform == 'tvos':
+    min_os_version_deployment_flag = '-mtvos-version-min'
+  elif config.apple_platform == 'tvossim':
+    min_os_version_deployment_flag = '-mtvos-simulator-version-min'
+  else:
+    lit_config.fatal('Unhandled Apple platform "{}"'.format(
+      config.apple_platform)
+    )
+  # We do not use `apple_target_os_tuple[2]` here because dyld
+  # doesn't handle it properly. rdar://problem/57133776.
+  config.substitutions.append(('%match_min_os_deployment_version_to_target',
+    '{}={}.{}'.format(
+      min_os_version_deployment_flag,
+      apple_target_os_tuple[0],
+      apple_target_os_tuple[1],
+    ))
+  )
+
   # Detect x86_64h
   try:
     output = subprocess.check_output(["sysctl", "hw.cpusubtype"])
     output_re = re.match("^hw.cpusubtype: ([0-9]+)$", output)
     if output_re:
       cpu_subtype = int(output_re.group(1))
       if cpu_subtype == 8: # x86_64h
         config.available_features.add('x86_64h')

compiler-rt/test/sanitizer_common/ios_commands/iossim_run.py

if '*' in arg or '?' in arg:
       rm_args.append(arg)
     else:
       # FIXME(dliew): pipes.quote() is deprecated
       rm_args.append(pipes.quote(arg))
   rm_cmd_line = ["/bin/rm"] + rm_args
   rm_cmd_line_str = ' '.join(rm_cmd_line)
   # We use `shell=True` so that any wildcard globs get expanded by the shell.
   exitcode = subprocess.call(rm_cmd_line_str, shell=True)
+elif prog == 'sw_vers':
+  args = sys.argv[2:]
+  if len(args) == 0:
+    print("Argument must be provided")
+    sys.exit(1)
+  if args[0] != '-productVersion':
+    print("Only -productVersion is supported")
+    sys.exit(1)
+  # sw_vers is not shipped in the simulator runtime so try to emulate `sw_vers
+  # -productVersion` by inspecting the environment of the simulator.
+  exitcode = subprocess.call(
+    [
+      "xcrun",
+      "simctl",
+      "spawn",
+      device_id,
+      'bin/bash',
+      '-c',
+      'echo $SIMULATOR_RUNTIME_VERSION'
+    ]
+  )
+  sys.exit(exitcode)
 else:
   exitcode = subprocess.call(["xcrun", "simctl", "spawn", device_id] + sys.argv[1:])
 if exitcode > 125:
   exitcode = 126
 sys.exit(exitcode)