__DATA not __DATA__ is the right segment name on darwin.
Spotted by Nick Kledzik.

llvm-svn: 47037
diff --git a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
index 0d10097..7c69aa1 100644
--- a/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
+++ b/llvm/lib/Target/ARM/ARMAsmPrinter.cpp
@@ -848,7 +848,7 @@
       if (I->hasExternalLinkage()) {
         if (const char *Directive = TAI->getZeroFillDirective()) {
           O << "\t.globl\t" << name << "\n";
-          O << Directive << "__DATA__, __common, " << name << ", "
+          O << Directive << "__DATA, __common, " << name << ", "
             << Size << ", " << Align << "\n";
           continue;
         }
diff --git a/llvm/lib/Target/X86/X86AsmPrinter.cpp b/llvm/lib/Target/X86/X86AsmPrinter.cpp
index 0b8c31c..727707b 100644
--- a/llvm/lib/Target/X86/X86AsmPrinter.cpp
+++ b/llvm/lib/Target/X86/X86AsmPrinter.cpp
@@ -183,7 +183,7 @@
       if (I->hasExternalLinkage()) {
         if (const char *Directive = TAI->getZeroFillDirective()) {
           O << "\t.globl " << name << "\n";
-          O << Directive << "__DATA__, __common, " << name << ", "
+          O << Directive << "__DATA, __common, " << name << ", "
             << Size << ", " << Align << "\n";
           continue;
         }