[Driver] Pass -f[no-]emulated-tls and set up ExplicitEmulatedTLS

Since LLVM r326341, default EmulatedTLS mode is decided in backend
according to target triple. Any front-end should pass -f[no]-emulated-tls
to backend and set up ExplicitEmulatedTLS only when the flags are used.

Differential Revision: https://reviews.llvm.org/D43965

llvm-svn: 326499

1 files changed, 6 insertions, 2 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 7e060bbcdf2..a8b7dd96644 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -942,8 +942,12 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
     }
   }
 
-  Opts.EmulatedTLS =
-      Args.hasFlag(OPT_femulated_tls, OPT_fno_emulated_tls, false);
+  if (Args.getLastArg(OPT_femulated_tls) ||
+      Args.getLastArg(OPT_fno_emulated_tls)) {
+    Opts.ExplicitEmulatedTLS = true;
+    Opts.EmulatedTLS =
+        Args.hasFlag(OPT_femulated_tls, OPT_fno_emulated_tls, false);
+  }
 
   if (Arg *A = Args.getLastArg(OPT_ftlsmodel_EQ)) {
     StringRef Name = A->getValue();