LLVM: Add ELF Note section to NaCl object files identifying them as such to gold

test/MC/ARM/elf-note-nacl.s

Index: test/MC/ARM/elf-note-nacl.s
diff --git a/test/MC/ARM/elf-note-nacl.s b/test/MC/ARM/elf-note-nacl.s
new file mode 100644
index 0000000000000000000000000000000000000000..4e5c1225352d921a0c1b0baf839deb8beed941ec
--- /dev/null
+++ b/test/MC/ARM/elf-note-nacl.s
@@ -0,0 +1,23 @@
+# RUN: llvm-mc -filetype=obj -triple armv7-none-nacl-gnueabi %s -o - \
+# RUN:   | llvm-objdump -triple armv7 -s - | FileCheck %s
+
+# Tests that NaCl object files contain an ELF note section that identifies them
+# to the binutils gold linker
+
+  .syntax unified
+  .text
+foo:
+  bx lr
+
+# There appears to be no way for llvm-objdump to show flags for sections, or
+# to dump groups like readelf
+# CHECK: .group        
+# CHECK: .note.NaCl.ABI.arm
+# contents of the words in the note section should be:
+# sizeof "NaCl"
+# sizeof "arm"
+# 1 (NT_VERSION)
+# "NaCl" with nul termination and padding to align 4
+# "arm" with nul termination and padding to align 4
+# CHECK-NEXT: 0000 05000000 04000000 01000000 4e61436c
+# CHECK-NEXT: 0010 00000000 61726d00