Add support for -fsanitize-blacklist and default blacklists for DFSan.
Also add some documentation.

Differential Revision: http://llvm-reviews.chandlerc.com/D1346

llvm-svn: 188403
diff --git a/clang/lib/Driver/SanitizerArgs.cpp b/clang/lib/Driver/SanitizerArgs.cpp
index 9351e51..fdabf7b 100644
--- a/clang/lib/Driver/SanitizerArgs.cpp
+++ b/clang/lib/Driver/SanitizerArgs.cpp
@@ -307,6 +307,9 @@
     BlacklistFile = "msan_blacklist.txt";
   else if (Kind & NeedsTsanRt)
     BlacklistFile = "tsan_blacklist.txt";
+  else if (Kind & NeedsDfsanRt)
+    BlacklistFile = "dfsan_abilist.txt";
+
   if (BlacklistFile) {
     SmallString<64> Path(D.ResourceDir);
     llvm::sys::path::append(Path, BlacklistFile);