[llvm-rc] Support '--' for delimiting options from input paths

This allows avoiding conflicts between paths that begin with the same
chars as some llvm-rc options (which can be used with either slashes
or dashes).

Differential Revision: https://reviews.llvm.org/D56743

llvm-svn: 351305
diff --git a/llvm/tools/llvm-rc/llvm-rc.cpp b/llvm/tools/llvm-rc/llvm-rc.cpp
index 4511c5c..54997e9 100644
--- a/llvm/tools/llvm-rc/llvm-rc.cpp
+++ b/llvm/tools/llvm-rc/llvm-rc.cpp
@@ -31,6 +31,7 @@
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/raw_ostream.h"
 
+#include <algorithm>
 #include <system_error>
 
 using namespace llvm;
@@ -85,7 +86,10 @@
 
   RcOptTable T;
   unsigned MAI, MAC;
-  ArrayRef<const char *> ArgsArr = makeArrayRef(Argv + 1, Argc - 1);
+  const char **DashDash = std::find_if(
+      Argv + 1, Argv + Argc, [](StringRef Str) { return Str == "--"; });
+  ArrayRef<const char *> ArgsArr = makeArrayRef(Argv + 1, DashDash);
+
   opt::InputArgList InputArgs = T.ParseArgs(ArgsArr, MAI, MAC);
 
   // The tool prints nothing when invoked with no command-line arguments.
@@ -97,6 +101,8 @@
   const bool BeVerbose = InputArgs.hasArg(OPT_VERBOSE);
 
   std::vector<std::string> InArgsInfo = InputArgs.getAllArgValues(OPT_INPUT);
+  if (DashDash != Argv + Argc)
+    InArgsInfo.insert(InArgsInfo.end(), DashDash + 1, Argv + Argc);
   if (InArgsInfo.size() != 1) {
     fatalError("Exactly one input file should be provided.");
   }