diff --git a/llvm/lib/MC/MCParser/ELFAsmParser.cpp b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
--- a/llvm/lib/MC/MCParser/ELFAsmParser.cpp
+++ b/llvm/lib/MC/MCParser/ELFAsmParser.cpp
@@ -326,6 +326,9 @@
     case 'G':
       flags |= ELF::SHF_GROUP;
       break;
+    case 'R':
+      flags |= ELF::SHF_GNU_RETAIN;
+      break;
     case '?':
       *UseLastGroup = true;
       break;
diff --git a/llvm/lib/MC/MCSectionELF.cpp b/llvm/lib/MC/MCSectionELF.cpp
--- a/llvm/lib/MC/MCSectionELF.cpp
+++ b/llvm/lib/MC/MCSectionELF.cpp
@@ -102,6 +102,8 @@
     OS << 'T';
   if (Flags & ELF::SHF_LINK_ORDER)
     OS << 'o';
+  if (Flags & ELF::SHF_GNU_RETAIN)
+    OS << 'R';
 
   // If there are target-specific flags, print them.
   Triple::ArchType Arch = T.getArch();
diff --git a/llvm/test/MC/ELF/section-gnu.s b/llvm/test/MC/ELF/section-gnu.s
new file mode 100644
--- /dev/null
+++ b/llvm/test/MC/ELF/section-gnu.s
@@ -0,0 +1,16 @@
+# RUN: llvm-mc -triple=x86_64 %s | FileCheck %s --check-prefix=ASM
+# RUN: llvm-mc -filetype=obj -triple=x86_64 %s | llvm-readobj -hS - | FileCheck %s --check-prefix=OBJ
+
+# ASM: .section retain,"aR",@progbits
+
+## Note: GNU as sets OSABI to GNU.
+# OBJ:      OS/ABI: SystemV (0x0)
+
+# OBJ:      Name: retain
+# OBJ-NEXT: Type: SHT_PROGBITS
+# OBJ-NEXT: Flags [
+# OBJ-NEXT:   SHF_ALLOC
+# OBJ-NEXT:   SHF_GNU_RETAIN
+# OBJ-NEXT: ]
+
+.section retain,"aR",@progbits