[CodeGen] Model machine debug metadata

Replace marker-based metadata operands with scoped references and inline DIExpression values. Add structured DILocation chains, instruction debug attachments, stack variable records, and entry values with unified verification, builder support, and deterministic cloning.

1 files changed, 13 insertions, 0 deletions

diff --git a/backend/lib/CodeGen/MachineMetadata.cpp b/backend/lib/CodeGen/MachineMetadata.cpp
index 24a04e9..f789a74 100644
--- a/backend/lib/CodeGen/MachineMetadata.cpp
+++ b/backend/lib/CodeGen/MachineMetadata.cpp
@@ -111,4 +111,17 @@ Expected<MachineMetadataInfo> MachineMetadataInfo::clone() const {
   return Result;
 }
 
+Expected<void> verifyMachineMetadataReference(MachineMetadataReference Reference,
+                                              const MachineMetadataInfo &Metadata) {
+  if (!Reference.isValid()) {
+    return makeUnexpected(ErrorCode::VerificationError, "machine metadata reference is invalid");
+  }
+  if (Reference.scope() == MachineMetadataScope::MachineFunction &&
+      Metadata.node(Reference.slot()) == nullptr) {
+    return makeUnexpected(ErrorCode::VerificationError,
+                          "machine metadata reference uses an undefined function slot");
+  }
+  return {};
+}
+
 } // namespace rcc