[LibFuzzer] Disable compiling and running the LibFuzzer dataflow sanitizer tests on Apple platforms.

[delcypher]

Summary

[LibFuzzer] Disable compiling and running the LibFuzzer dataflow sanitizer tests on Apple platforms.

This fixes a broken part of the build on OSX as the dataflow sanitizer is not supported
on OSX yet.

[kcc]

LGTM

lib/Fuzzer/test/CMakeLists.txt

set_target_properties(LLVMFuzzer-Unittest
   PROPERTIES RUNTIME_OUTPUT_DIRECTORY
   "${CMAKE_CURRENT_BINARY_DIR}"
 )
 ###############################################################################
 # Additional tests
 ###############################################################################
 
 include_directories(..)
+
+if(APPLE)
+  message(WARNING "Dataflow sanitizer is not supported on Apple platforms."
+    " Building and running LibFuzzer dataflow sanitizer tests is disabled."
+    )
+  set(HAS_DFSAN 0)
+else()
+  set(HAS_DFSAN 1)
   add_subdirectory(dfsan)
+endif()
+
 add_subdirectory(uninstrumented)
 add_subdirectory(ubsan)
 add_subdirectory(trace-bb)
 add_subdirectory(trace-pc)
 
 ###############################################################################
 # Configure lit to run the tests
 #

lib/Fuzzer/test/fuzzer-dfsan.test

+REQUIRES: dfsan
 CHECK1: BINGO
 CHECK2: BINGO
 CHECK3: BINGO
 CHECK4: BINGO
 
 CHECK_DFSanCmpCallback: DFSanCmpCallback: PC
 CHECK_DFSanSwitchCallback: DFSanSwitchCallback: PC
 CHECK_DFSanMemcmpCallback: DFSanMemcmpCallback: Pos

lib/Fuzzer/test/lit.cfg

 import lit.formats
 
 config.name = "LLVMFuzzer"
 config.test_format = lit.formats.ShTest(True)
 config.suffixes = ['.test']
 config.test_source_root = os.path.dirname(__file__)
 
 # Tweak PATH to include llvm tools dir and current exec dir.
 llvm_tools_dir = getattr(config, 'llvm_tools_dir', None)
 if (not llvm_tools_dir) or (not os.path.exists(llvm_tools_dir)):
   lit_config.fatal("Invalid llvm_tools_dir config attribute: %r" % llvm_tools_dir)
 path = os.path.pathsep.join((llvm_tools_dir, config.test_exec_root,
                              config.environment['PATH']))
 config.environment['PATH'] = path
 
+if config.has_dfsan:
+  lit_config.note('dfsan feature available')
+  config.available_features.add('dfsan')
+else:
+  lit_config.note('dfsan feature unavailable')
+

lib/Fuzzer/test/lit.site.cfg.in

 config.test_exec_root = "@CMAKE_CURRENT_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
+config.has_dfsan = True if @HAS_DFSAN@ == 1 else False
 lit_config.load_config(config, "@CMAKE_CURRENT_SOURCE_DIR@/lit.cfg")