From 4f7b41c3c711d6c6fa4e422f3eec8961c91eea7a Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Sun, 16 Aug 2026 15:39:45 +0800
Subject: tablegen: Generate GlobalISel match tables

---
 .../rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h  | 70 ++++++++++++++++++++++
 .../rcc/CodeGen/GlobalISel/InstructionSelector.h   |  4 +-
 2 files changed, 72 insertions(+), 2 deletions(-)
 create mode 100644 backend/include/rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h

(limited to 'backend/include/rcc/CodeGen/GlobalISel')

diff --git a/backend/include/rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h b/backend/include/rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h
new file mode 100644
index 0000000..807cb4a
--- /dev/null
+++ b/backend/include/rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h
@@ -0,0 +1,70 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#ifndef RCC_CODEGEN_GLOBALISEL_GIMATCHTABLEEXECUTOR_H
+#define RCC_CODEGEN_GLOBALISEL_GIMATCHTABLEEXECUTOR_H
+
+#include "rcc/CodeGen/MachineIRTypes.h"
+#include "rcc/Support/Error.h"
+
+#include <cstdint>
+#include <span>
+#include <string_view>
+
+namespace rcc {
+
+class MachineFunction;
+class MachineInstr;
+class TargetDescription;
+
+enum class GIMatchTypeKind : std::uint8_t {
+  Any,
+  Scalar,
+  Pointer,
+};
+
+enum class GIMatchTableOpcode : std::uint8_t {
+  CheckOpcode,
+  CheckOperandType,
+  CheckOperandBank,
+  CheckOperandClass,
+  MutateOpcode,
+  AppendImmediate,
+  Complete,
+};
+
+struct GIMatchTableInstruction final {
+  GIMatchTableOpcode Opcode = GIMatchTableOpcode::Complete;
+  std::uint16_t OperandIndex = 0;
+  std::uint32_t Value = 0;
+  std::uint32_t Auxiliary = 0;
+  std::int64_t Immediate = 0;
+};
+
+struct GIMatchTableRule final {
+  std::string_view Name;
+  std::uint32_t Priority = 0;
+  std::uint32_t FirstInstruction = 0;
+  std::uint32_t InstructionCount = 0;
+};
+
+struct GIMatchTable final {
+  std::span<const GIMatchTableInstruction> Instructions;
+  std::span<const GIMatchTableRule> Rules;
+};
+
+class GIMatchTableExecutor {
+public:
+  [[nodiscard]] Expected<bool> match(const GIMatchTable &Table, const MachineInstr &Instruction,
+                                     const MachineFunction &Function,
+                                     const TargetDescription &Target) const;
+
+  // A false result means that no table rule matched. The executor completes all
+  // predicates before applying the selected rule to MachineIR.
+  [[nodiscard]] Expected<bool> select(const GIMatchTable &Table, MachineInstr &Instruction,
+                                      MachineFunction &Function,
+                                      const TargetDescription &Target) const;
+};
+
+} // namespace rcc
+
+#endif // RCC_CODEGEN_GLOBALISEL_GIMATCHTABLEEXECUTOR_H
diff --git a/backend/include/rcc/CodeGen/GlobalISel/InstructionSelector.h b/backend/include/rcc/CodeGen/GlobalISel/InstructionSelector.h
index 4bea4e7..36fca8d 100644
--- a/backend/include/rcc/CodeGen/GlobalISel/InstructionSelector.h
+++ b/backend/include/rcc/CodeGen/GlobalISel/InstructionSelector.h
@@ -3,7 +3,7 @@
 #ifndef RCC_CODEGEN_GLOBALISEL_INSTRUCTIONSELECTOR_H
 #define RCC_CODEGEN_GLOBALISEL_INSTRUCTIONSELECTOR_H
 
-#include "rcc/CodeGen/MachineIRTypes.h"
+#include "rcc/CodeGen/GlobalISel/GIMatchTableExecutor.h"
 #include "rcc/Support/Error.h"
 
 namespace rcc {
@@ -12,7 +12,7 @@ class MachineFunction;
 class MachineInstr;
 class TargetDescription;
 
-class InstructionSelector {
+class InstructionSelector : public GIMatchTableExecutor {
 public:
   virtual ~InstructionSelector() = default;
 
-- 
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