Support -masm= flag for x86 assembly targets.

For assembly files without .intel_syntax or .att_syntax directives, allow the
-masm= flag to supply a default assembly dialect. For example,

C:\TMP> type intel.s
.text
mov al,0

C:\TMP> clang -masm=intel -c intel.s

Without this patch, one would need to pass an "-mllvm -x86-asm-syntax=" flag
directly to the backend.
C:\TMP> clang -mllvm --x86-asm-syntax=intel -c intel.s

Differentials Review: http://reviews.llvm.org/D22285

llvm-svn: 275877

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index af70017..6dfd004e 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -6460,6 +6460,20 @@ void ClangAs::AddMIPSTargetArgs(const ArgList &Args,
   CmdArgs.push_back(ABIName.data());
 }
 
+void ClangAs::AddX86TargetArgs(const ArgList &Args,
+                               ArgStringList &CmdArgs) const {
+  if (Arg *A = Args.getLastArg(options::OPT_masm_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value == "intel" || Value == "att") {
+      CmdArgs.push_back("-mllvm");
+      CmdArgs.push_back(Args.MakeArgString("-x86-asm-syntax=" + Value));
+    } else {
+      getToolChain().getDriver().Diag(diag::err_drv_unsupported_option_argument)
+          << A->getOption().getName() << Value;
+    }
+  }
+}
+
 void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
                            const InputInfo &Output, const InputInfoList &Inputs,
                            const ArgList &Args,
@@ -6607,6 +6621,11 @@ void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
   case llvm::Triple::mips64el:
     AddMIPSTargetArgs(Args, CmdArgs);
     break;
+    
+  case llvm::Triple::x86:
+  case llvm::Triple::x86_64:
+    AddX86TargetArgs(Args, CmdArgs);
+    break;
   }
 
   // Consume all the warning flags. Usually this would be handled more