[MSVC Compat] Only warn for unknown clang-cl arguments
Summary:
MSVC's driver accepts all unknown arguments but warns about them. clang
by default rejects all unknown arguments. This causes issues
specifically with build systems such as autoconf which liberally pass
things such as $LDFLAGS to the compiler and expect everything to work.
This patch teaches clang-cl to ignore unknown driver arguments.
Reviewers: rnk
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D16511
llvm-svn: 258720
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 2bbcb27..814eb35 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -9708,6 +9708,10 @@
options::OPT__SLASH_MT, options::OPT__SLASH_MTd))
A->render(Args, CmdArgs);
+ // Pass through all unknown arguments so that the fallback command can see
+ // them too.
+ Args.AddAllArgs(CmdArgs, options::OPT_UNKNOWN);
+
// Input filename.
assert(Inputs.size() == 1);
const InputInfo &II = Inputs[0];