From 36b0be1ec1558f88d4f031a1817c3a4c2cba07a6 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Sat, 22 Aug 2026 18:59:22 +0800
Subject: [CodeGen] Match LLVM machine debug stripping

---
 backend/lib/CodeGen/CMakeLists.txt        |  2 ++
 backend/lib/CodeGen/MIRPrinter.cpp        |  3 ++-
 backend/lib/CodeGen/MachineInstr.cpp      | 16 +++++++++++++++
 backend/lib/CodeGen/MachineStripDebug.cpp | 34 +++++++++++++++++++++++++++++++
 4 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 backend/lib/CodeGen/MachineStripDebug.cpp

(limited to 'backend/lib/CodeGen')

diff --git a/backend/lib/CodeGen/CMakeLists.txt b/backend/lib/CodeGen/CMakeLists.txt
index 2fc7254..b95fe42 100644
--- a/backend/lib/CodeGen/CMakeLists.txt
+++ b/backend/lib/CodeGen/CMakeLists.txt
@@ -23,6 +23,7 @@ set(
   MachineCopyPropagation.cpp
   MachineCSE.cpp
   MachineDebugInfo.cpp
+  MachineStripDebug.cpp
   MachineDCE.cpp
   MachineFrameInfo.cpp
   MachineFinalization.cpp
@@ -111,6 +112,7 @@ set(
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineCopyPropagation.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineCSE.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineDebugInfo.h"
+  "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineStripDebug.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineDCE.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineFrameInfo.h"
   "${RCC_BACKEND_SOURCE_DIR}/include/rcc/CodeGen/MachineFinalization.h"
diff --git a/backend/lib/CodeGen/MIRPrinter.cpp b/backend/lib/CodeGen/MIRPrinter.cpp
index 5eb244a..c684368 100644
--- a/backend/lib/CodeGen/MIRPrinter.cpp
+++ b/backend/lib/CodeGen/MIRPrinter.cpp
@@ -1935,7 +1935,8 @@ Expected<void> BodyPrinter::printRegisterOperand(const MachineOperand &Operand,
     Output.append("internal ");
   if (Flags.has(RegisterOperandFlag::EarlyClobber))
     Output.append("early-clobber ");
-  if (Flags.has(RegisterOperandFlag::Debug))
+  if (Flags.has(RegisterOperandFlag::Debug) &&
+      (Operand.parent() == nullptr || !Operand.parent()->isDebugInstr()))
     Output.append("debug-use ");
   if (Flags.has(RegisterOperandFlag::Renamable))
     Output.append("renamable ");
diff --git a/backend/lib/CodeGen/MachineInstr.cpp b/backend/lib/CodeGen/MachineInstr.cpp
index f4602e0..55b4ce9 100644
--- a/backend/lib/CodeGen/MachineInstr.cpp
+++ b/backend/lib/CodeGen/MachineInstr.cpp
@@ -2,6 +2,7 @@
 
 #include "rcc/CodeGen/MachineInstr.h"
 
+#include "rcc/CodeGen/GenericOpcodes.h"
 #include "rcc/CodeGen/MachineBasicBlock.h"
 #include "rcc/CodeGen/MachineFunction.h"
 #include "rcc/CodeGen/MachineMemOperand.h"
@@ -18,6 +19,14 @@
 
 namespace rcc {
 
+bool MachineInstr::isDebugInstr() const noexcept {
+  return InstructionOpcode == rcc::opcode(GenericOpcode::DBG_VALUE) ||
+         InstructionOpcode == rcc::opcode(GenericOpcode::DBG_VALUE_LIST) ||
+         InstructionOpcode == rcc::opcode(GenericOpcode::DBG_LABEL) ||
+         InstructionOpcode == rcc::opcode(GenericOpcode::DBG_INSTR_REF) ||
+         InstructionOpcode == rcc::opcode(GenericOpcode::DBG_PHI);
+}
+
 MachineInstr::MachineInstr(MachineFunction &OwnerFunction, Opcode InstructionOpcode,
                            MachineInstrStableID StableID)
     : OwnerFunction(&OwnerFunction), InstructionOpcode(InstructionOpcode), StableID(StableID) {}
@@ -97,6 +106,13 @@ Expected<void> MachineInstr::insertOperand(std::size_t Index, MachineOperand &&O
     return makeUnexpected(ErrorCode::InvalidArgument,
                           "register operand references an unknown virtual register");
   }
+  if (Operand.isUse() && isDebugInstr()) {
+    RegisterOperandFlags RegisterFlags = Operand.registerFlags();
+    RegisterFlags.set(RegisterOperandFlag::Debug);
+    auto Updated = Operand.setRegisterFlags(RegisterFlags);
+    if (!Updated)
+      return std::unexpected(Updated.error());
+  }
 
   Operands.insert(Operands.begin() + static_cast<std::ptrdiff_t>(Index), std::move(Operand));
   adjustTiesForInsertion(Index);
diff --git a/backend/lib/CodeGen/MachineStripDebug.cpp b/backend/lib/CodeGen/MachineStripDebug.cpp
new file mode 100644
index 0000000..4699ef0
--- /dev/null
+++ b/backend/lib/CodeGen/MachineStripDebug.cpp
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "rcc/CodeGen/MachineStripDebug.h"
+
+#include "rcc/CodeGen/MachineBasicBlock.h"
+#include "rcc/CodeGen/MachineFunction.h"
+#include "rcc/CodeGen/MachineInstr.h"
+
+namespace rcc {
+
+Expected<bool> stripDebugMachineFunction(MachineFunction &Function) {
+  bool Changed = false;
+  for (MachineBasicBlock *Block = Function.firstBlock(); Block != nullptr; Block = Block->next()) {
+    for (MachineInstr *Instruction = Block->firstInstruction(); Instruction != nullptr;) {
+      MachineInstr *Next = Instruction->next();
+      if (Instruction->isDebugInstr() && Instruction->operandCount() > 1) {
+        auto Removed = Block->removeInstruction(*Instruction);
+        if (!Removed)
+          return std::unexpected(Removed.error());
+        Changed = true;
+        Instruction = Next;
+        continue;
+      }
+      if (Instruction->debugLocation()) {
+        Instruction->clearDebugLocation();
+        Changed = true;
+      }
+      Instruction = Next;
+    }
+  }
+  return Changed;
+}
+
+} // namespace rcc
-- 
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