DebugInfo: Flag type unit references as declarations

This ensures DWARF consumers don't confuse these references for
definitions. I'd argue it might be nice to improve debuggers so we don't
need this, but it's just one field in an abbreviation anyway - so it
doesn't seem worth the fight.

llvm-svn: 200569
diff --git a/llvm/test/DebugInfo/X86/generate-odr-hash.ll b/llvm/test/DebugInfo/X86/generate-odr-hash.ll
index 2ccbc98..74c1699 100644
--- a/llvm/test/DebugInfo/X86/generate-odr-hash.ll
+++ b/llvm/test/DebugInfo/X86/generate-odr-hash.ll
@@ -51,8 +51,10 @@
 ; CHECK: Compile Unit: length = [[CU_SIZE:[0-9a-f]+]]
 
 ; CHECK: DW_TAG_structure_type
+; CHECK-NEXT: DW_AT_declaration
 ; CHECK-NEXT: DW_AT_signature
 ; CHECK: DW_TAG_class_type
+; CHECK-NEXT: DW_AT_declaration
 ; CHECK-NEXT: DW_AT_signature
 
 ; Ensure the CU-local type 'walrus' is not placed in a type unit.