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.

llvm-svn: 219010

1 files changed, 3 insertions, 2 deletions

diff --git a/llvm/test/DebugInfo/ARM/sectionorder.ll b/llvm/test/DebugInfo/ARM/sectionorder.ll
index a7030cd1b67..24733d96b62 100644
--- a/llvm/test/DebugInfo/ARM/sectionorder.ll
+++ b/llvm/test/DebugInfo/ARM/sectionorder.ll
@@ -11,7 +11,8 @@ target triple = "thumbv7-apple-ios"
 !llvm.module.flags = !{!3, !4}
 !llvm.dbg.cu = !{!0}
 
-!0 = metadata !{i32 786449, i32 0, i32 12, metadata !"test.c", metadata !"/Volumes/Data/radar/15623193", metadata !"LLVM", i1 true, i1 false, metadata !"", i32 0, metadata !1, metadata !1, metadata !1, metadata !1} ; [ DW_TAG_compile_unit ] [/Volumes/Data/radar/15623193/test.c] [DW_LANG_C99]
+!0 = metadata !{metadata !"0x11\0012\00LLVM\001\00\00\00\00", metadata !5, metadata !1, metadata !1, metadata !1, metadata !1, null} ; [ DW_TAG_compile_unit ] [/Volumes/Data/radar/15623193/test.c] [DW_LANG_C99]
 !1 = metadata !{}
 !3 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
-!4 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
+!4 = metadata !{i32 1, metadata !"Debug Info Version", i32 2}
+!5 = metadata !{metadata !"test.c", metadata !"/Volumes/Data/radar/15623193"}