From 75f1223070749b0df3002226ebbb474c68c71f90 Mon Sep 17 00:00:00 2001
From: Richard-Qin-X <richard.qin.001@gmail.com>
Date: Sat, 22 Aug 2026 19:16:18 +0800
Subject: [RISCV] Generate MC pseudo lowering

---
 backend/utils/TableGen/MCPseudoLoweringEmitter.cpp | 69 ++++++++++++++++++++++
 1 file changed, 69 insertions(+)
 create mode 100644 backend/utils/TableGen/MCPseudoLoweringEmitter.cpp

(limited to 'backend/utils/TableGen/MCPseudoLoweringEmitter.cpp')

diff --git a/backend/utils/TableGen/MCPseudoLoweringEmitter.cpp b/backend/utils/TableGen/MCPseudoLoweringEmitter.cpp
new file mode 100644
index 0000000..5afa911
--- /dev/null
+++ b/backend/utils/TableGen/MCPseudoLoweringEmitter.cpp
@@ -0,0 +1,69 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#include "TableGenBackends.h"
+
+#include <cstddef>
+#include <ostream>
+#include <sstream>
+#include <string>
+#include <string_view>
+
+namespace rcc::targetgen {
+
+std::string emitMCPseudoLowering(const NormalizedTargetModel &Model, std::string_view SourceName) {
+  std::ostringstream Output;
+  Output << "// SPDX-License-Identifier: GPL-3.0-or-later\n\n";
+  Output << "// This file is generated by rcc-tblgen from ";
+  appendQuoted(Output, SourceName);
+  Output << ". Do not edit it manually.\n\n";
+  Output << "#ifdef GET_MC_PSEUDO_LOWERING\n\n";
+  Output << "[[nodiscard]] Expected<std::optional<mc::MCInst>>\n"
+            "lowerGeneratedMCPseudo(const MachineInstr &Instruction,\n"
+            "                       MachineMCContext &Context) {\n"
+            "  switch (Instruction.opcode().value()) {\n"
+            "  default:\n"
+            "    return std::optional<mc::MCInst>{};\n";
+  for (const NormalizedMCPseudoExpansion &Expansion : Model.MCPseudoExpansions) {
+    Output << "  case " << Expansion.PseudoOpcode << ": {\n"
+           << "    mc::MCInst Result(mc::MCOpcode::fromValue(" << Expansion.ResultOpcode
+           << "));\n"
+              "    Result.setFlags(Instruction.flags().rawValue());\n"
+              "    Result.setSourceIdentity(Instruction.stableID().value());\n"
+              "    Result.reserveOperands("
+           << Expansion.Operands.size() << ");\n";
+    for (std::size_t Index = 0; Index < Expansion.Operands.size(); ++Index) {
+      const NormalizedMCPseudoOperand &Operand = Expansion.Operands[Index];
+      switch (Operand.Kind) {
+      case NormalizedMCPseudoOperandKind::SourceOperand:
+        Output << "    const MachineOperand *Operand" << Index << " = Instruction.operandAt("
+               << Operand.Value << ");\n"
+               << "    if (Operand" << Index << " == nullptr)\n"
+               << "      return makeUnexpected(ErrorCode::AssemblyLoweringFailed,\n"
+                  "                            \"MC pseudo has too few operands\");\n"
+               << "    auto Lowered" << Index << " =\n"
+               << "        lowerOperand(*Operand" << Index
+               << ", Instruction.function(), Context);\n"
+               << "    if (!Lowered" << Index << ")\n"
+               << "      return std::unexpected(Lowered" << Index << ".error());\n"
+               << "    Result.addOperand(std::move(*Lowered" << Index << "));\n";
+        break;
+      case NormalizedMCPseudoOperandKind::Register:
+        Output << "    Result.addOperand(mc::MCOperand::registerOperand(\n"
+                  "        mc::MCRegister::fromValue("
+               << Operand.Value << ")));\n";
+        break;
+      case NormalizedMCPseudoOperandKind::Immediate:
+        Output << "    Result.addOperand(mc::MCOperand::immediate(" << Operand.Immediate << "));\n";
+        break;
+      }
+    }
+    Output << "    return std::optional<mc::MCInst>{std::move(Result)};\n"
+              "  }\n";
+  }
+  Output << "  }\n"
+            "}\n\n"
+            "#endif // GET_MC_PSEUDO_LOWERING\n";
+  return Output.str();
+}
+
+} // namespace rcc::targetgen
-- 
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