Fix `skipIfSanitized` decorator on macOS

[JDevlieghere]

Summary

For security reasons, DYLD_INSERT_LIBRARIES is not propagated to a child process. This breaks the skipIfSanitized decorator, which checks for the environment variable being set. Instead, always set the ASAN_OPTIONS and make the decorator check for that.

[vsk]

Thanks, lgtm.

[jasonmolenda]

fwiw this behavior is documented here,

https://developer.apple.com/documentation/bundleresources/entitlements/com_apple_security_cs_allow-dyld-environment-variables?language=objc

lldb/trunk/lit/Suite/lit.cfg

 config.suffixes = ['.py']
 
 # test_source_root: The root path where tests are located.
 # test_exec_root: The root path where tests should be run.
 config.test_source_root = os.path.join(config.lldb_src_root, 'packages',
                                        'Python', 'lldbsuite', 'test')
 config.test_exec_root = config.test_source_root
 
+if 'Address' in config.llvm_use_sanitizer:
+  config.environment['ASAN_OPTIONS'] = 'detect_stack_use_after_return=1'
   # macOS flags needed for LLDB built with address sanitizer.
-if 'Address' in config.llvm_use_sanitizer and \
-   'Darwin' in config.host_os and \
-   'x86' in config.host_triple:
+  if 'Darwin' in config.host_os and 'x86' in config.host_triple:
     import subprocess
     resource_dir = subprocess.check_output(
-    config.cmake_cxx_compiler +' -print-resource-dir', shell=True).strip()
+        [config.cmake_cxx_compiler, '-print-resource-dir']).strip()
     runtime = os.path.join(resource_dir, 'lib', 'darwin',
                            'libclang_rt.asan_osx_dynamic.dylib')
-  config.environment['ASAN_OPTIONS'] = \
-    'detect_stack_use_after_return=1'
     config.environment['DYLD_INSERT_LIBRARIES'] = runtime
 
 # Shared library build of LLVM may require LD_LIBRARY_PATH or equivalent.
 def find_shlibpath_var():
   if platform.system() in ['Linux', 'FreeBSD', 'NetBSD', 'SunOS']:
     yield 'LD_LIBRARY_PATH'
   elif platform.system() == 'Darwin':
     yield 'DYLD_LIBRARY_PATH'
   elif platform.system() == 'Windows':

lldb/trunk/packages/Python/lldbsuite/test/decorators.py

def is_feature_enabled(self):
                 if re.match('%s: 1\s*' % feature, output):
                     return None
                 else:
                     return "%s is not supported on this system." % feature
             except subprocess.CalledProcessError:
                 return "%s is not supported on this system." % feature
     return skipTestIfFn(is_feature_enabled)
 
-def skipIfSanitized(func):
+def skipIfAsan(func):
     """Skip this test if the environment is set up to run LLDB itself under ASAN."""
-    def is_sanitized():
-        if (('DYLD_INSERT_LIBRARIES' in os.environ) and
-                'libclang_rt.asan' in os.environ['DYLD_INSERT_LIBRARIES']):
+    def is_asan():
+        if ('ASAN_OPTIONS' in os.environ):
             return "ASAN unsupported"
         return None
-    return skipTestIfFn(is_sanitized)(func)
+    return skipTestIfFn(is_asan)(func)

lldb/trunk/packages/Python/lldbsuite/test/functionalities/exec/TestExec.py

class ExecTestCase(TestBase):
 
     NO_DEBUG_INFO_TESTCASE = True
 
     mydir = TestBase.compute_mydir(__file__)
 
     @expectedFailureAll(archs=['i386'], bugnumber="rdar://28656532")
     @expectedFailureAll(oslist=["ios", "tvos", "watchos", "bridgeos"], bugnumber="rdar://problem/34559552") # this exec test has problems on ios systems
     @expectedFailureNetBSD
-    @skipIfSanitized # rdar://problem/43756823
+    @skipIfAsan # rdar://problem/43756823
     @skipIfWindows
     def test_hitting_exec (self):
         self.do_test(False)
 
     @expectedFailureAll(archs=['i386'], bugnumber="rdar://28656532")
     @expectedFailureAll(oslist=["ios", "tvos", "watchos", "bridgeos"], bugnumber="rdar://problem/34559552") # this exec test has problems on ios systems
     @expectedFailureNetBSD
-    @skipIfSanitized # rdar://problem/43756823
+    @skipIfAsan # rdar://problem/43756823
     @skipIfWindows
     def test_skipping_exec (self):
         self.do_test(True)
 
     def do_test(self, skip_exec):
         self.build()
         exe = self.getBuildArtifact("a.out")
         secondprog = self.getBuildArtifact("secondprog")

lldb/trunk/packages/Python/lldbsuite/test/python_api/hello_world/TestHelloWorld.py

def test_with_attach_to_process_with_id_api(self):
         # Let's check the stack traces of the attached process.
         stacktraces = lldbutil.print_stacktraces(process, string_buffer=True)
         self.expect(stacktraces, exe=False,
                     substrs=['main.c:%d' % self.line2,
                              '(int)argc=2'])
 
     @add_test_categories(['pyapi'])
     @skipIfiOSSimulator
-    @skipIfSanitized # FIXME: Hangs indefinitely.
+    @skipIfAsan # FIXME: Hangs indefinitely.
     @expectedFailureNetBSD
     def test_with_attach_to_process_with_name_api(self):
         """Create target, spawn a process, and attach to it with process name."""
         exe = '%s_%d'%(self.getBuildArtifact(self.testMethodName), os.getpid())
         d = {'EXE': exe}
         self.build(dictionary=d)
         self.setTearDownCleanup(dictionary=d)
         target = self.dbg.CreateTarget(exe)