llvm-link: Improve diagnostic for module-level metadata mismatch

This might produce hard to read/illegible diagnostics for especially
weird/non-trivial module metadata but integers are about all we are
using these days, so seems more useful than not.

Patch based on work by Kristina Brooks - thanks!

Differential Revision: https://reviews.llvm.org/D52952

llvm-svn: 344011

3 files changed, 8 insertions, 0 deletions

diff --git a/llvm/test/Linker/Inputs/metadata-mismatch-a.ll b/llvm/test/Linker/Inputs/metadata-mismatch-a.ll
new file mode 100644
index 00000000000..742ae5ca3ef
--- /dev/null
+++ b/llvm/test/Linker/Inputs/metadata-mismatch-a.ll
@@ -0,0 +1,3 @@
+
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"Dwarf Version", i32 4}
diff --git a/llvm/test/Linker/Inputs/metadata-mismatch-b.ll b/llvm/test/Linker/Inputs/metadata-mismatch-b.ll
new file mode 100644
index 00000000000..198c479c981
--- /dev/null
+++ b/llvm/test/Linker/Inputs/metadata-mismatch-b.ll
@@ -0,0 +1,2 @@
+!llvm.module.flags = !{!1}
+!1 = !{i32 2, !"Dwarf Version", i32 5}
diff --git a/llvm/test/Linker/metadata-mismatch.test b/llvm/test/Linker/metadata-mismatch.test
new file mode 100644
index 00000000000..9767f8d2e4c
--- /dev/null
+++ b/llvm/test/Linker/metadata-mismatch.test
@@ -0,0 +1,3 @@
+; RUN: llvm-link %p/Inputs/metadata-mismatch-a.ll %p/Inputs/metadata-mismatch-b.ll -S 2>&1 | FileCheck %s
+
+; CHECK: warning: linking module flags 'Dwarf Version': IDs have conflicting values ('i32 5' from {{.*}}/metadata-mismatch-b.ll with 'i32 4' from llvm-link)