[clang][slh] Forward mSLH only to Clang CC1

Summary:
-mno-speculative-load-hardening isn't a cc1 option, therefore,
before this change:

clang -mno-speculative-load-hardening hello.cpp

would have the following error:

error: unknown argument: '-mno-speculative-load-hardening'

This change will only ever forward -mspeculative-load-hardening
which is a CC1 option based on which flag was passed to clang.

Also added a test that uses this option that fails if an error like the
above is ever thrown.

Thank you ericwf for help debugging and fixing this error.

Reviewers: chandlerc, EricWF

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54763

llvm-svn: 347582

1 files changed, 3 insertions, 2 deletions

diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 9a36f7b429c..6b2083ce025 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -4452,8 +4452,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
 
   Args.AddLastArg(CmdArgs, options::OPT_pthread);
 
-  Args.AddLastArg(CmdArgs, options::OPT_mspeculative_load_hardening,
-                  options::OPT_mno_speculative_load_hardening);
+  if (Args.hasFlag(options::OPT_mspeculative_load_hardening, options::OPT_mno_speculative_load_hardening,
+                   false))
+    CmdArgs.push_back(Args.MakeArgString("-mspeculative-load-hardening"));
 
   RenderSSPOptions(TC, Args, CmdArgs, KernelOrKext);