Revert "Revert "DI: Fold constant arguments into a single MDString""

This reverts commit r218918, effectively reapplying r218914 after fixing
an Ocaml bindings test and an Asan crash.  The root cause of the latter
was a tightened-up check in `DILexicalBlock::Verify()`, so I'll file a
PR to investigate who requires the loose check (and why).

Original commit message follows.

--

This patch addresses the first stage of PR17891 by folding constant
arguments together into a single MDString.  Integers are stringified and
a `\0` character is used as a separator.

Part of PR17891.

Note: I've attached my testcases upgrade scripts to the PR.  If I've
just broken your out-of-tree testcases, they might help.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219010 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 2 deletions

diff --git a/test/Linker/debug-info-version-a.ll b/test/Linker/debug-info-version-a.ll
index c3d9c87a2e9..64a058381f9 100644
--- a/test/Linker/debug-info-version-a.ll
+++ b/test/Linker/debug-info-version-a.ll
@@ -10,7 +10,7 @@
 !llvm.module.flags = !{ !0 }
 !llvm.dbg.cu = !{!1}
 
-!0 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
-!1 = metadata !{i32 589841, metadata !2, i32 12, metadata !"clang", i1 true, metadata !"", i32 0, metadata !3, metadata !3, metadata !3, null, null, metadata !""} ; [ DW_TAG_compile_unit ]
+!0 = metadata !{i32 2, metadata !"Debug Info Version", i32 2}
+!1 = metadata !{metadata !"0x11\0012\00clang\001\00\000\00\000", metadata !2, metadata !3, metadata !3, metadata !3, null, null} ; [ DW_TAG_compile_unit ]
 !2 = metadata !{metadata !"a.c", metadata !""}
 !3 = metadata !{}