[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, 19 insertions, 0 deletions

diff --git a/backend/unittests/CodeGen/MachineFrameInfoTest.cpp b/backend/unittests/CodeGen/MachineFrameInfoTest.cpp
index 7368815..c9289c7 100644
--- a/backend/unittests/CodeGen/MachineFrameInfoTest.cpp
+++ b/backend/unittests/CodeGen/MachineFrameInfoTest.cpp
@@ -2,8 +2,11 @@
 
 #include "rcc/CodeGen/MachineFrameInfo.h"
 
+#include "rcc/CodeGen/MachineDebugInfo.h"
+
 #include <cstdint>
 #include <iostream>
+#include <optional>
 #include <string_view>
 
 namespace {
@@ -130,6 +133,22 @@ void testInvalidDescriptions(TestContext &Context) {
   Context.expect(!Frame.createObject(InvalidLifetime),
                  "stack object lifetime must reject equal boundaries");
 
+  auto InvalidDebugInfo = fixedObject(8, 8);
+  InvalidDebugInfo.DebugInfo.emplace();
+  Context.expect(!Frame.createObject(InvalidDebugInfo),
+                 "stack object debug information must not be structurally empty");
+
+  auto DebugObject = fixedObject(8, 8);
+  DebugObject.DebugInfo = rcc::MachineVariableDebugInfo{
+      .Variable = rcc::MachineMetadataReference::embeddedIR(1),
+      .Expression = rcc::MachineMetadataValue::expression(rcc::MachineDIExpression{}),
+      .Location = std::nullopt,
+  };
+  auto DebugIndex = Frame.createObject(DebugObject);
+  Context.expect(DebugIndex.has_value() &&
+                     Frame.object(*DebugIndex)->description()->DebugInfo == DebugObject.DebugInfo,
+                 "stack object debug information must remain structured");
+
   Context.expect(!rcc::StackID::targetStack(4), "target stack IDs must not overlap built-in IDs");
   auto TargetStack = rcc::StackID::targetStack(256);
   auto Target = fixedObject(8, 8);