From a2f8d7c5e22b510965327383410bd576f7cf28e7 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Thu, 13 Aug 2026 04:17:52 +0800
Subject: [CodeGen] Split machine liveness components

---
 backend/include/rcc/CodeGen/LiveVariables.h | 105 ++++++++++++++++++++++++++++
 1 file changed, 105 insertions(+)
 create mode 100644 backend/include/rcc/CodeGen/LiveVariables.h

(limited to 'backend/include/rcc/CodeGen/LiveVariables.h')

diff --git a/backend/include/rcc/CodeGen/LiveVariables.h b/backend/include/rcc/CodeGen/LiveVariables.h
new file mode 100644
index 0000000..28a66c1
--- /dev/null
+++ b/backend/include/rcc/CodeGen/LiveVariables.h
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_LIVEVARIABLES_H
+#define RCC_CODEGEN_LIVEVARIABLES_H
+
+#include "rcc/CodeGen/LiveRegUnits.h"
+#include "rcc/CodeGen/MachinePass.h"
+#include "rcc/CodeGen/Register.h"
+#include "rcc/Support/Error.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+#include <unordered_map>
+
+namespace rcc {
+
+class MachineBasicBlock;
+class MachineFunction;
+class TargetDescription;
+
+class RegisterLaneSet final {
+public:
+  [[nodiscard]] LaneMask lanes(Register Reg) const noexcept;
+  [[nodiscard]] bool contains(Register Reg, LaneMask Lanes = LaneMask::all()) const noexcept;
+  [[nodiscard]] bool intersects(Register Reg, LaneMask Lanes = LaneMask::all()) const noexcept;
+  [[nodiscard]] bool empty() const noexcept {
+    return Values.empty();
+  }
+
+  void add(Register Reg, LaneMask Lanes);
+  void remove(Register Reg, LaneMask Lanes);
+  void unite(const RegisterLaneSet &Other);
+  void subtract(const RegisterLaneSet &Other);
+
+  [[nodiscard]] const std::unordered_map<Register, LaneMask> &entries() const noexcept {
+    return Values;
+  }
+
+  friend bool operator==(const RegisterLaneSet &, const RegisterLaneSet &) = default;
+
+private:
+  std::unordered_map<Register, LaneMask> Values;
+};
+
+struct MachineBlockLiveness final {
+  RegisterLaneSet VirtualUses;
+  RegisterLaneSet VirtualDefs;
+  RegisterLaneSet VirtualLiveIn;
+  RegisterLaneSet VirtualLiveOut;
+  LiveRegUnits PhysicalUses;
+  LiveRegUnits PhysicalDefs;
+  LiveRegUnits PhysicalLiveIn;
+  LiveRegUnits PhysicalLiveOut;
+};
+
+class LiveVariablesAnalysis final {
+public:
+  class Result final {
+  public:
+    [[nodiscard]] MachineBlockLiveness &getOrCreateBlock(const MachineBasicBlock &Block);
+    [[nodiscard]] const MachineBlockLiveness *block(const MachineBasicBlock &Block) const noexcept;
+    [[nodiscard]] bool isLiveIn(const MachineBasicBlock &Block, Register Reg,
+                                LaneMask Lanes = LaneMask::all()) const noexcept;
+    [[nodiscard]] bool isLiveOut(const MachineBasicBlock &Block, Register Reg,
+                                 LaneMask Lanes = LaneMask::all()) const noexcept;
+    [[nodiscard]] bool isUnitLiveIn(const MachineBasicBlock &Block, RegisterUnitID Unit,
+                                    LaneMask Lanes = LaneMask::all()) const noexcept;
+    [[nodiscard]] bool isUnitLiveOut(const MachineBasicBlock &Block, RegisterUnitID Unit,
+                                     LaneMask Lanes = LaneMask::all()) const noexcept;
+
+    [[nodiscard]] bool invalidate(const MachineFunction &,
+                                  const PreservedAnalyses &Preserved) const noexcept;
+
+  private:
+    std::unordered_map<const MachineBasicBlock *, MachineBlockLiveness> Blocks;
+
+    friend class LiveVariablesAnalysis;
+  };
+
+  [[nodiscard]] static constexpr std::string_view name() noexcept {
+    return "LiveVariables";
+  }
+
+  [[nodiscard]] static Expected<Result>
+  run(MachineFunction &Function, const TargetDescription &Target, MachineAnalysisManager &Analyses);
+};
+
+class RebuildMachineLivenessPass final : public MachineFunctionPass {
+public:
+  [[nodiscard]] const MachinePassContract &contract() const noexcept override;
+  [[nodiscard]] Expected<MachinePassResult> run(MachineFunction &Function,
+                                                const TargetDescription &Target,
+                                                MachineAnalysisManager &Analyses) override;
+};
+
+[[nodiscard]] Expected<void> verifyTrackedMachineLiveness(const MachineFunction &Function,
+                                                          const TargetDescription &Target);
+[[nodiscard]] Expected<bool> rebuildMachineLiveness(MachineFunction &Function,
+                                                    const TargetDescription &Target);
+[[nodiscard]] Expected<void> registerStage11MachineAnalyses(MachineAnalysisManager &Analyses);
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_LIVEVARIABLES_H
-- 
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