Bitcode: Add METADATA_NODE and METADATA_VALUE

This reflects the typelessness of `Metadata` in the bitcode format,
removing types from all metadata operands.

`METADATA_VALUE` represents a `ValueAsMetadata`, and always has two
fields: the type and the value.

`METADATA_NODE` represents an `MDNode`, and unlike `METADATA_OLD_NODE`,
doesn't store types.  It stores operands at their ID+1 so that `0` can
reference `nullptr` operands.

Part of PR21532.

llvm-svn: 224073

2 files changed, 26 insertions, 0 deletions

diff --git a/llvm/test/Bitcode/metadata.3.5.ll b/llvm/test/Bitcode/metadata.3.5.ll
new file mode 100644
index 00000000000..028c89cf358
--- /dev/null
+++ b/llvm/test/Bitcode/metadata.3.5.ll
@@ -0,0 +1,26 @@
+; RUN: llvm-dis < %s.bc | FileCheck %s
+
+; Check that metadata encoded in 3.5 is correctly understood going forward.
+;
+; Bitcode assembled by llvm-as v3.5.0.
+
+define void @foo(i32 %v) {
+; CHECK: entry:
+entry:
+; CHECK-NEXT: call void @llvm.bar(metadata !0)
+  call void @llvm.bar(metadata !0)
+
+; CHECK-NEXT: ret void, !baz !1
+  ret void, !baz !1
+}
+
+declare void @llvm.bar(metadata)
+
+@global = global i32 0
+
+; CHECK: !0 = metadata !{metadata !1, metadata !2, i32* @global, null}
+; CHECK: !1 = metadata !{metadata !2, null}
+; CHECK: !2 = metadata !{}
+!0 = metadata !{metadata !1, metadata !2, i32* @global, null}
+!1 = metadata !{metadata !2, null}
+!2 = metadata !{}
diff --git a/llvm/test/Bitcode/metadata.3.5.ll.bc b/llvm/test/Bitcode/metadata.3.5.ll.bc
new file mode 100644
index 00000000000..1857465755d
--- /dev/null
+++ b/llvm/test/Bitcode/metadata.3.5.ll.bc