Just disable the hidden-visibility optimization for now by hiding it behind

a -cc1 option.  The Darwin linker complains about mixed visibility when linking
gcc-built objects with clang-built objects, and the optimization isn't really
that valuable.  Platforms with less ornery linkers can feel free to enable this.

llvm-svn: 110979

clang/lib/Frontend/CompilerInvocation.cpp

@@ -845,6 +845,7 @@ static void ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args,
   Opts.DebugPass = Args.getLastArgValue(OPT_mdebug_pass);
   Opts.DisableFPElim = Args.hasArg(OPT_mdisable_fp_elim);
   Opts.FloatABI = Args.getLastArgValue(OPT_mfloat_abi);
+  Opts.HiddenWeakVTables = Args.hasArg(OPT_fhidden_weak_vtables);
   Opts.LimitFloatPrecision = Args.getLastArgValue(OPT_mlimit_float_precision);
   Opts.NoZeroInitializedInBSS = Args.hasArg(OPT_mno_zero_initialized_in_bss);
   Opts.RelaxAll = Args.hasArg(OPT_mrelax_all);