[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, 22 insertions, 3 deletions

diff --git a/backend/lib/CodeGen/MachineVerifier.cpp b/backend/lib/CodeGen/MachineVerifier.cpp
index 2a29343..7e050ec 100644
--- a/backend/lib/CodeGen/MachineVerifier.cpp
+++ b/backend/lib/CodeGen/MachineVerifier.cpp
@@ -272,6 +272,11 @@ private:
     if (Instruction.sourceLocation() && !Instruction.sourceLocation()->isValid()) {
       return fail("instruction has an invalid source location");
     }
+    if (Instruction.debugLocation()) {
+      auto DebugLocationResult = Instruction.debugLocation()->verify(Function.metadata());
+      if (!DebugLocationResult)
+        return failWith("instruction debug location", DebugLocationResult.error());
+    }
     if (Instruction.origin() && Instruction.origin()->value() == 0)
       return fail("instruction has an invalid origin ID");
 
@@ -293,9 +298,10 @@ private:
           Address != nullptr && (Address->FunctionName.empty() || Address->BlockName.empty())) {
         return fail("block-address operand has an incomplete name");
       }
-      if (const auto *Metadata = Operand.getIf<MetadataOperand>();
-          Metadata != nullptr && Metadata->Marker.empty()) {
-        return fail("metadata operand has an empty marker");
+      if (const auto *Metadata = Operand.getIf<MetadataOperand>(); Metadata != nullptr) {
+        auto MetadataResult = Metadata->Value.verify(Function.metadata());
+        if (!MetadataResult)
+          return failWith("metadata operand", MetadataResult.error());
       }
       if (const auto *Symbol = Operand.getIf<MCSymbolOperand>();
           Symbol != nullptr && Symbol->Name.empty()) {
@@ -342,6 +348,11 @@ private:
           return fail("stack object lifetime references a detached or unknown instruction");
         }
       }
+      if (Description->DebugInfo) {
+        auto DebugInfoResult = Description->DebugInfo->verify(Function.metadata());
+        if (!DebugInfoResult)
+          return failWith("stack object debug information", DebugInfoResult.error());
+      }
     }
     return {};
   }
@@ -356,6 +367,14 @@ private:
       if (!Target.registers().isKnownPhysicalRegister(Reg))
         return fail("callee-saved register list references an unknown physical register");
     }
+    for (const MachineEntryValueInfo &EntryValue : Records.entryValues()) {
+      if (!Target.registers().isKnownPhysicalRegister(EntryValue.Reg)) {
+        return fail("entry-value record references an unknown physical register");
+      }
+      auto DebugInfoResult = EntryValue.DebugInfo.verify(Function.metadata());
+      if (!DebugInfoResult)
+        return failWith("entry-value debug information", DebugInfoResult.error());
+    }
 
     auto VerifyCall = [this](MachineInstrStableID ID,
                              std::string_view Kind) -> Expected<const MachineInstr *> {