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

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

Index: test/MC/ARM/elf-note-nacl.ll
diff --git a/test/MC/ARM/elf-note-nacl.ll b/test/MC/ARM/elf-note-nacl.ll
new file mode 100644
index 0000000000000000000000000000000000000000..8551cf52b4a99b29e5dc8c43b28db90ebda1906b
--- /dev/null
+++ b/test/MC/ARM/elf-note-nacl.ll
@@ -0,0 +1,22 @@
+; RUN: llc -filetype=obj -mtriple 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
+
+define void @main() {
+  ret void
+}
+
+; 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
+; The 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