subclassed MCAsmStreamer

tools/llvm-mc/llvm-mc.cpp

Index: tools/llvm-mc/llvm-mc.cpp
diff --git a/tools/llvm-mc/llvm-mc.cpp b/tools/llvm-mc/llvm-mc.cpp
index 96d3206a78316c1cca6bdad27097c095111352f3..049db4ce490093c7a352f9e8b278a1db1eb5242c 100644
--- a/tools/llvm-mc/llvm-mc.cpp
+++ b/tools/llvm-mc/llvm-mc.cpp
@@ -466,10 +466,21 @@ int main(int argc, char **argv) {
       MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU);
     }
     auto FOut = llvm::make_unique<formatted_raw_ostream>(*OS);
-    Str.reset(TheTarget->createAsmStreamer(
-        Ctx, std::move(FOut), /*asmverbose*/ true,
-        /*useDwarfDirectory*/ true, IP, CE, MAB, ShowInst));
 
+    if (T.isOSNaCl()) {
+      Str.reset(TheTarget->createNaClAsmStreamer(
+		Ctx, std::move(FOut), /*asmverbose*/ true,
+		/*useDwarfDirectory*/ true, IP, CE, MAB, ShowInst));
+      if (NoExecStack)
+	Str->InitSections(true);
+
+      Str->InitSections(NoExecStack);
+      initializeNaClMCStreamer(*Str.get(), Ctx, T);
+    } else {
+      Str.reset(TheTarget->createAsmStreamer(
+	        Ctx, std::move(FOut), /*asmverbose*/ true,
+		/*useDwarfDirectory*/ true, IP, CE, MAB, ShowInst));
+    }
   } else if (FileType == OFT_Null) {
     Str.reset(TheTarget->createNullStreamer(Ctx));
   } else {