[PATCH] [RFC] Introduce support for multiple sanitizer blacklists (Clang side).

[Alexey Samsonov]

Support for adding special case list entries in commandline seems an overkill to me. Now, if you presumably need logic to dynamically construct special case list from object files, I don't see why Clang's codegen will be a good place for it. It won't even use this list, only pass it to the DFSan backend...

================
Comment at: lib/Driver/SanitizerArgs.cpp:118
@@ -137,1 +117,3 @@
+  // blacklist in the resource directory.
+  if (!Args.hasArg(options::OPT_fno_sanitize_blacklist)) {
     std::string BLPath;
----------------
Hm. So now -fno-sanitize-blacklist only disables the default blacklist, but not blacklists specified in -fsanitize-blacklist= arguments? This looks weird. I'd suggest the following semantics:
  * default blacklist in resource directory is implicitly enabled.
  * -fsanitize-blacklist= specifes one more blacklist to use
  * -fno-sanitize-blacklist - discards all blacklists previously defined in the command line, and the default blacklist.

That is,
  BLSet.insert(DefaultBlacklist);
  foreach (arg)
    if arg is -fsanitize-blacklist=, insert the blacklist into BLSet
    else if arg is -fno-sanitize-blacklist, clear BLSet.

http://reviews.llvm.org/D4547