Index: lib/MC/MCSectionELF.cpp
===================================================================
--- lib/MC/MCSectionELF.cpp
+++ lib/MC/MCSectionELF.cpp
@@ -14,6 +14,7 @@
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/Support/ELF.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Format.h"
 
 using namespace llvm;
 
@@ -53,6 +54,67 @@
   OS << '"';
 }
 
+static inline void clearFlags(unsigned &val, unsigned flags) {
+    val &= ~flags;
+}
+
+// print section header flags to OS and return the set of unknown flags
+static unsigned
+printSectionFlags(raw_ostream &OS, const Triple &T, unsigned Flags) {
+  if (Flags & ELF::SHF_ALLOC) {
+    clearFlags(Flags, ELF::SHF_ALLOC);
+    OS << 'a';
+  }
+  if (Flags & ELF::SHF_EXCLUDE) {
+    clearFlags(Flags, ELF::SHF_EXCLUDE);
+    OS << 'e';
+  }
+  if (Flags & ELF::SHF_EXECINSTR) {
+    clearFlags(Flags, ELF::SHF_EXECINSTR);
+    OS << 'x';
+  }
+  if (Flags & ELF::SHF_GROUP) {
+    clearFlags(Flags, ELF::SHF_GROUP);
+    OS << 'G';
+  }
+  if (Flags & ELF::SHF_WRITE) {
+    clearFlags(Flags, ELF::SHF_WRITE);
+    OS << 'w';
+  }
+  if (Flags & ELF::SHF_MERGE) {
+    clearFlags(Flags, ELF::SHF_MERGE);
+    OS << 'M';
+  }
+  if (Flags & ELF::SHF_STRINGS) {
+    clearFlags(Flags, ELF::SHF_STRINGS);
+    OS << 'S';
+  }
+  if (Flags & ELF::SHF_TLS) {
+    clearFlags(Flags, ELF::SHF_TLS);
+    OS << 'T';
+  }
+
+  // If there are target-specific flags, print them.
+  Triple::ArchType Arch = T.getArch();
+  if (Arch == Triple::xcore) {
+    if (Flags & ELF::XCORE_SHF_CP_SECTION) {
+      clearFlags(Flags, ELF::XCORE_SHF_CP_SECTION);
+      OS << 'c';
+    }
+    if (Flags & ELF::XCORE_SHF_DP_SECTION) {
+      clearFlags(Flags, ELF::XCORE_SHF_DP_SECTION);
+      OS << 'd';
+    }
+  } else if (Arch == Triple::arm || Arch == Triple::armeb ||
+             Arch == Triple::thumb || Arch == Triple::thumbeb) {
+    if (Flags & ELF::SHF_ARM_PURECODE) {
+      clearFlags(Flags, ELF::SHF_ARM_PURECODE);
+      OS << 'y';
+    }
+  }
+  return Flags;
+}
+
 void MCSectionELF::PrintSwitchToSection(const MCAsmInfo &MAI, const Triple &T,
                                         raw_ostream &OS,
                                         const MCExpr *Subsection) const {
@@ -87,37 +149,15 @@
     return;
   }
 
-  OS << ",\"";
-  if (Flags & ELF::SHF_ALLOC)
-    OS << 'a';
-  if (Flags & ELF::SHF_EXCLUDE)
-    OS << 'e';
-  if (Flags & ELF::SHF_EXECINSTR)
-    OS << 'x';
-  if (Flags & ELF::SHF_GROUP)
-    OS << 'G';
-  if (Flags & ELF::SHF_WRITE)
-    OS << 'w';
-  if (Flags & ELF::SHF_MERGE)
-    OS << 'M';
-  if (Flags & ELF::SHF_STRINGS)
-    OS << 'S';
-  if (Flags & ELF::SHF_TLS)
-    OS << 'T';
-
-  // If there are target-specific flags, print them.
-  Triple::ArchType Arch = T.getArch();
-  if (Arch == Triple::xcore) {
-    if (Flags & ELF::XCORE_SHF_CP_SECTION)
-      OS << 'c';
-    if (Flags & ELF::XCORE_SHF_DP_SECTION)
-      OS << 'd';
-  } else if (Arch == Triple::arm || Arch == Triple::armeb ||
-             Arch == Triple::thumb || Arch == Triple::thumbeb) {
-    if (Flags & ELF::SHF_ARM_PURECODE)
-      OS << 'y';
-  }
 
+  OS << ",\"";
+  llvm::SmallString<8> flagText;
+  raw_svector_ostream SOS { flagText };
+  unsigned UnknownFlags = printSectionFlags(SOS, T, Flags);
+  if (UnknownFlags)
+      OS << format_hex(Flags, 0);
+  else
+      OS << flagText;
   OS << '"';
 
   OS << ',';
Index: test/CodeGen/Mips/2008-07-15-SmallSection.ll
===================================================================
--- test/CodeGen/Mips/2008-07-15-SmallSection.ll
+++ test/CodeGen/Mips/2008-07-15-SmallSection.ll
@@ -5,11 +5,11 @@
 @s0 = constant [8 x i8] c"AAAAAAA\00", align 4
 
 ; CHECK: .type  foo,@object
-; CHECK-NEXT: .section .sdata,"aw",@progbits
+; CHECK-NEXT: .section .sdata,"0x10000003",@progbits
 @foo = global %struct.anon { i32 2, i32 3 }
 
 ; CHECK:  .type bar,@object
-; CHECK-NEXT:  .section  .sbss,"aw",@nobits
+; CHECK-NEXT:  .section  .sbss,"0x10000003",@nobits
 @bar = global %struct.anon zeroinitializer 
 
 define i8* @A0() nounwind {
Index: test/CodeGen/Mips/mips-shf-gprel.s
===================================================================
--- test/CodeGen/Mips/mips-shf-gprel.s
+++ test/CodeGen/Mips/mips-shf-gprel.s
@@ -4,12 +4,18 @@
 # RUN: llvm-mc -filetype=obj -triple=mips-unknown-linux %s -o - \
 # RUN:   | llvm-readobj -s | FileCheck %s
 
+# RUN: llvm-mc -filetype=asm -triple=mips-unknown-linux %s -o - \
+# RUN:   | FileCheck -check-prefix=ASM %s
+
   .sdata
   .word 0
 
   .sbss
   .zero 4
 
+# ASM: .section .sdata,"0x10000003",@progbits
+# ASM: .section    .sbss,"0x10000003",@nobits
+
 # CHECK:      Name: .sdata
 # CHECK-NEXT: Type: SHT_PROGBITS
 # CHECK-NEXT: Flags [ (0x10000003)