Merge pull request #39012 from apple/support-xcode-13-beta4-5.5-08092021

Support Xcode 13 beta 4

Author: shahmishal

test/lit.cfg

@@ -97,7 +97,7 @@ def get_simulator_command(run_os, run_cpu, sdk_path):
         else:
             return "simctl spawn --standalone 'iPhone 8'"
     elif run_os == 'tvos':
-        return "simctl spawn --standalone 'Apple TV 4K'"
+        return "simctl spawn --standalone 'Apple TV'"
     elif run_os == 'watchos':
         if run_cpu == "i386":
            if min(darwin_get_watchos_sim_vers()) > 6.2:
@@ -2128,6 +2128,13 @@ config.substitutions.append(('%FileCheck', run_filecheck))
 config.substitutions.append(('%raw-FileCheck', shell_quote(config.filecheck)))
 config.substitutions.append(('%import-libdispatch', getattr(config, 'import_libdispatch', '')))
 
+# Disabe COW sanity checks in the swift runtime by default.
+# (But it's required to set this environment variable to something)
+config.environment['SWIFT_DEBUG_ENABLE_COW_CHECKS'] = 'false'
+
+# Add this to the command which runs an executable to enable COW checks in the swift runtime.
+config.substitutions.append(('%enable-cow-checking', TARGET_ENV_PREFIX + 'SWIFT_DEBUG_ENABLE_COW_CHECKS=true;'))
+
 if config.lldb_build_root != "":
     lldb_python_path = get_lldb_python_path(config.lldb_build_root)
     lldb_python_interpreter = get_lldb_python_interpreter(config.lldb_build_root)
@@ -2152,9 +2159,6 @@ config.environment[TARGET_ENV_PREFIX + 'SWIFT_DETERMINISTIC_HASHING'] = '1'
 # Enable malloc scribble during tests by default.
 config.environment[TARGET_ENV_PREFIX + 'SWIFT_DEBUG_ENABLE_MALLOC_SCRIBBLE'] = 'YES'
 
-# Enable COW sanity checks in the swift runtime by default.
-config.environment['SWIFT_DEBUG_ENABLE_COW_CHECKS'] = 'true'
-
 # Run lsb_release on the target to be tested and return the results.
 def linux_get_lsb_release():
     lsb_release_path = '/usr/bin/lsb_release'