diff --git a/include/llvm/Support/MachO.h b/include/llvm/Support/MachO.h
index 9d401c8d366..59998ada020 100644
--- a/include/llvm/Support/MachO.h
+++ b/include/llvm/Support/MachO.h
@@ -417,6 +417,15 @@ namespace llvm {
       X86_64_RELOC_TLV             = 9
     };
 
+    // Values for segment_command.initprot.
+    // From <mach/vm_prot.h>
+    enum {
+      VM_PROT_READ    = 0x1,
+      VM_PROT_WRITE   = 0x2,
+      VM_PROT_EXECUTE = 0x4
+    };
+
+
     // Structs from <mach-o/loader.h>
 
     struct mach_header {
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index d0bfc65cb27..3531ab2247d 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -185,8 +185,10 @@ void MachObjectWriter::WriteSegmentLoadCommand(unsigned NumSections,
     Write32(SectionDataStartOffset); // file offset
     Write32(SectionDataSize); // file size
   }
-  Write32(0x7); // maxprot
-  Write32(0x7); // initprot
+  // maxprot
+  Write32(MachO::VM_PROT_READ | MachO::VM_PROT_WRITE | MachO::VM_PROT_EXECUTE); 
+  // initprot
+  Write32(MachO::VM_PROT_READ | MachO::VM_PROT_WRITE | MachO::VM_PROT_EXECUTE); 
   Write32(NumSections);
   Write32(0); // flags