[llvm-rc] Support joined or separate spelling for /fo flag

CMake invokes rc using the joined spelling which appears to be supported
by Microsoft's rc implementation, so we should support it as well.

Differential Revision: https://reviews.llvm.org/D54191

llvm-svn: 346470

3 files changed, 5 insertions, 1 deletions

diff --git a/llvm/test/tools/llvm-rc/Inputs/empty.rc b/llvm/test/tools/llvm-rc/Inputs/empty.rc
new file mode 100644
index 00000000000..e69de29bb2d
--- /dev/null
+++ b/llvm/test/tools/llvm-rc/Inputs/empty.rc
diff --git a/llvm/test/tools/llvm-rc/flags.test b/llvm/test/tools/llvm-rc/flags.test
new file mode 100644
index 00000000000..452e90a406b
--- /dev/null
+++ b/llvm/test/tools/llvm-rc/flags.test
@@ -0,0 +1,4 @@
+; RUN: llvm-rc /dry-run /FO %t %p/Inputs/empty.rc 2>&1 | FileCheck %s --allow-empty --check-prefix=FO
+; RUN: llvm-rc /dry-run /FO%t %p/Inputs/empty.rc 2>&1 | FileCheck %s --allow-empty --check-prefix=FO
+
+; FO-NOT: Exactly one input file should be provided.
diff --git a/llvm/tools/llvm-rc/Opts.td b/llvm/tools/llvm-rc/Opts.td
index 11f40f57103..3ff5ac2d498 100644
--- a/llvm/tools/llvm-rc/Opts.td
+++ b/llvm/tools/llvm-rc/Opts.td
@@ -4,7 +4,7 @@ include "llvm/Option/OptParser.td"
 // These options seem to be important for the tool
 // and should be implemented.
 
-def FILEOUT : Separate<[ "/", "-" ], "FO">,
+def FILEOUT : JoinedOrSeparate<[ "/", "-" ], "FO">,
               HelpText<"Change the output file location.">;
 
 def DEFINE : Separate<[ "/", "-" ], "D">,