Assembler: Darwin variables defined via .set are no-dead-strip.

For gas compatibility.

rdar://12219394

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163854 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 55ef01c..849b7c6 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -221,7 +221,8 @@
   /// return the contents from the current token up to the end or comma.
   StringRef ParseStringToComma();
 
-  bool ParseAssignment(StringRef Name, bool allow_redef);
+  bool ParseAssignment(StringRef Name, bool allow_redef,
+                       bool NoDeadStrip = false);
 
   bool ParsePrimaryExpr(const MCExpr *&Res, SMLoc &EndLoc);
   bool ParseBinOpRHS(unsigned Precedence, const MCExpr *&Res, SMLoc &EndLoc);
@@ -1697,7 +1698,8 @@
   llvm_unreachable("Unknown expr kind!");
 }
 
-bool AsmParser::ParseAssignment(StringRef Name, bool allow_redef) {
+bool AsmParser::ParseAssignment(StringRef Name, bool allow_redef,
+                                bool NoDeadStrip) {
   // FIXME: Use better location, we should use proper tokens.
   SMLoc EqualLoc = Lexer.getLoc();
 
@@ -1752,6 +1754,9 @@
 
   // Do the assignment.
   Out.EmitAssignment(Sym, Value);
+  if (NoDeadStrip)
+    Out.EmitSymbolAttribute(Sym, MCSA_NoDeadStrip);
+
 
   return false;
 }
@@ -1809,7 +1814,7 @@
     return TokError("unexpected token in '" + Twine(IDVal) + "'");
   Lex();
 
-  return ParseAssignment(Name, allow_redef);
+  return ParseAssignment(Name, allow_redef, true);
 }
 
 bool AsmParser::ParseEscapedString(std::string &Data) {