[libcxx] [test] Fix the _supportsVerify check on Windows by fixing quoting

[mstorsjo]

Summary

The pipes.quote function quotes using single quotes, the same goes
for the newer shlex.quote (which is the preferred form in Python 3).
This isn't suitable for quoting in command lines on Windows (and the
documentation for shlex.quote even says it's only usable for Unix
shells).

In general, the python subprocess.list2cmdline function should do
proper quoting for the platform's current shell. However, it doesn't
quote the ';' char, which we pass within some arguments to run.py.
Therefore use the custom reimplementation from lit.TestRunner.

This didn't matter for command lines that are executed by either bash
or the lit internal shell, but if executing things directly using
subprocess.call, as in _supportsVerify, the quoted path to %{cxx}
fails to be resolved by the Windows shell.

This unlocks 114 tests that previously were skipped on Windows.

This is one out of two possible ways of fixing the same problem; this
would seem like the proper solution, but ended up being a mess,
so therefore mostly posting it for reference.

[ldionne]

I like this better than the other approach, actually, because of the chicken-and-egg issue with the other one.

[mstorsjo]

Rerun CI after fixing the failing testcases that this unlocks.

libcxx/utils/libcxx/test/config.py

 #===----------------------------------------------------------------------===##
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 # See https://llvm.org/LICENSE.txt for license information.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 #
 #===----------------------------------------------------------------------===##
 
 import copy
 import os
 import pkgutil
 import pipes
+import platform
 import re
 import shlex
 import shutil
 import sys
 
 from libcxx.compiler import CXXCompiler
 from libcxx.test.target_info import make_target_info
 import libcxx.util
 import libcxx.test.features
 import libcxx.test.newconfig
 import libcxx.test.params
+import lit
 
 def loadSiteConfig(lit_config, config, param_name, env_name):
     # We haven't loaded the site specific configuration (the user is
     # probably trying to run on a test file directly, and either the site
     # configuration hasn't been created by the build system, or we are in an
     # out-of-tree build situation).
     site_cfg = lit_config.params.get(param_name,
                                      os.environ.get(env_name))
def configure_modules(self):
             shutil.rmtree(module_cache)
         os.makedirs(module_cache)
         self.cxx.modules_flags += modules_flags + \
             ['-fmodules-cache-path=' + module_cache]
         if enable_modules:
             self.config.available_features.add('-fmodules')
             self.cxx.useModules()
 
+    def quote(self, s):
+        if platform.system() == 'Windows':
+            return lit.TestRunner.quote_windows_command([s])
+        return pipes.quote(s)
+
     def configure_substitutions(self):
         sub = self.config.substitutions
-        sub.append(('%{cxx}', pipes.quote(self.cxx.path)))
+        sub.append(('%{cxx}', self.quote(self.cxx.path)))
         flags = self.cxx.flags + (self.cxx.modules_flags if self.cxx.use_modules else [])
         compile_flags = self.cxx.compile_flags + (self.cxx.warning_flags if self.cxx.use_warnings else [])
-        sub.append(('%{flags}',         ' '.join(map(pipes.quote, flags))))
-        sub.append(('%{compile_flags}', ' '.join(map(pipes.quote, compile_flags))))
-        sub.append(('%{link_flags}',    ' '.join(map(pipes.quote, self.cxx.link_flags))))
+        sub.append(('%{flags}',         ' '.join(map(self.quote, flags))))
+        sub.append(('%{compile_flags}', ' '.join(map(self.quote, compile_flags))))
+        sub.append(('%{link_flags}',    ' '.join(map(self.quote, self.cxx.link_flags))))
 
         codesign_ident = self.get_lit_conf('llvm_codesign_identity', '')
-        env_vars = ' '.join('%s=%s' % (k, pipes.quote(v)) for (k, v) in self.exec_env.items())
+        env_vars = ' '.join('%s=%s' % (k, self.quote(v)) for (k, v) in self.exec_env.items())
         exec_args = [
             '--execdir %T',
             '--codesign_identity "{}"'.format(codesign_ident),
             '--env {}'.format(env_vars)
         ]
         sub.append(('%{exec}', '{} {} -- '.format(self.executor, ' '.join(exec_args))))
 
     def configure_env(self):
         self.config.environment = dict(os.environ)
 
     def add_path(self, dest_env, new_path):
         self.target_info.add_path(dest_env, new_path)

llvm/utils/lit/lit/TestRunner.py

def quote_windows_command(seq):
     for arg in seq:
         bs_buf = []
 
         # Add a space to separate this argument from the others
         if result:
             result.append(' ')
 
         # This logic differs from upstream list2cmdline.
-        needquote = (" " in arg) or ("\t" in arg) or ("\"" in arg) or ("[" in arg) or not arg
+        needquote = (" " in arg) or ("\t" in arg) or ("\"" in arg) or ("[" in arg) or (";" in arg) or not arg
         if needquote:
             result.append('"')
 
         for c in arg:
             if c == '\\':
                 # Don't know if we need to double yet.
                 bs_buf.append(c)
             elif c == '"':