From c9634fa9f529afbdf622a9cd96741bd09d14ef86 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Sat, 1 Aug 2026 13:55:21 +0800
Subject: [CodeGen] Add MachineFrameInfo

Model stable frame indices, stack object kinds, tombstones, lifetimes, and frozen layouts. Validate owned frame references in the builder and verifier, and remap complete frame state during MachineFunction cloning.
---
 backend/lib/CodeGen/MachineIRBuilder.cpp | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

(limited to 'backend/lib/CodeGen/MachineIRBuilder.cpp')

diff --git a/backend/lib/CodeGen/MachineIRBuilder.cpp b/backend/lib/CodeGen/MachineIRBuilder.cpp
index 8f80ad6..185b7df 100644
--- a/backend/lib/CodeGen/MachineIRBuilder.cpp
+++ b/backend/lib/CodeGen/MachineIRBuilder.cpp
@@ -3,6 +3,7 @@
 #include "rcc/CodeGen/MachineIRBuilder.h"
 
 #include "rcc/CodeGen/MachineBasicBlock.h"
+#include "rcc/CodeGen/MachineFrameInfo.h"
 #include "rcc/CodeGen/MachineFunction.h"
 #include "rcc/CodeGen/MachineInstr.h"
 #include "rcc/CodeGen/MachineMemOperand.h"
@@ -332,6 +333,15 @@ Expected<void> MachineInstrBuilder::validateInsertionPoint() const {
   return {};
 }
 
+Expected<void> MachineInstrBuilder::validateFrameReference(FrameIndex Index) const {
+  const StackObject *Object = Function->frameInfo().object(Index);
+  if (Object == nullptr || Object->description()->IsDead) {
+    return makeUnexpected(ErrorCode::InvalidArgument,
+                          "builder references an unknown or dead stack object");
+  }
+  return {};
+}
+
 Expected<void> MachineInstrBuilder::validateOperandOwnership(const MachineOperand &Operand) const {
   if (Operand.parent() != nullptr) {
     return makeUnexpected(ErrorCode::InvalidArgument,
@@ -349,6 +359,11 @@ Expected<void> MachineInstrBuilder::validateOperandOwnership(const MachineOperan
     return makeUnexpected(ErrorCode::InvalidArgument,
                           "builder operand references an unknown virtual register");
   }
+  if (const auto *Frame = Operand.getIf<FrameIndexOperand>(); Frame != nullptr) {
+    auto FrameResult = validateFrameReference(Frame->Index);
+    if (!FrameResult)
+      return FrameResult;
+  }
   return {};
 }
 
@@ -389,6 +404,13 @@ Expected<MachineInstr *> MachineInstrBuilder::build() {
     if (!Ownership)
       return std::unexpected(Ownership.error());
   }
+  for (const MachineMemOperand *MemOperand : MemOperands) {
+    if (const auto Frame = MemOperand->description().Base.frameIndex()) {
+      auto FrameResult = validateFrameReference(*Frame);
+      if (!FrameResult)
+        return std::unexpected(FrameResult.error());
+    }
+  }
 
   auto ExplicitValidation = Instructions->validateExplicitOperands(
       Descriptor->InstructionOpcode, ExplicitOperands, Function->registerInfo());
-- 
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