[RISCV GlobalISel] Adding initial GlobalISel infrastructure

[wwei]

Summary

Add an initial GlobalISel skeleton for RISCV. It can only run ir translator for ret void.

Patch by Andrew Wei

[dsanders]

LGTM. This looks like the normal initial boilerplate

[Petar.Avramovic]

Since there are no generic instructions in test function you can run all globalisel passes for it, not just irtranslator.
I got two compiler/tablegen warnings. Other then that look good.

llvm/lib/Target/RISCV/RISCVInstructionSelector.cpp

66–68

This defines RISCVInstructionSelector::selectImpl , but it is unused at the moment.

llvm/lib/Target/RISCV/RISCVRegisterBanks.td

14

RegisterBankEmitter emits warning here:
Register bank names should be distinct from register classes to avoid ambiguous MIR
RegisterBank was declared here
def GPRRegBank : RegisterBank<"GPR", [GPR]>;
RegisterClass was declared here
def GPR : RegisterClass<"RISCV", [XLenVT], 32, (add

[wwei]

Some changes for this update:

1. Rename the GPRRegBank from GPR to GPRB
2. Add using of RISCVInstructionSelector::selectImpl in RISCVInstructionSelector.cpp.
3. Add a seperate test case for running all globalisel passes.

[wwei]

llvm/lib/Target/RISCV/RISCVRegisterBanks.td

14

Done. GPR was changed into GPRB

[wwei]

llvm/lib/Target/RISCV/RISCVInstructionSelector.cpp

66–68

Done. I have add the call for selectImpl in RISCVInstructionSelector::select function.,

llvm/lib/Target/RISCV/CMakeLists.txt

 set(LLVM_TARGET_DEFINITIONS RISCV.td)
 
 tablegen(LLVM RISCVGenAsmMatcher.inc -gen-asm-matcher)
 tablegen(LLVM RISCVGenAsmWriter.inc -gen-asm-writer)
 tablegen(LLVM RISCVGenCompressInstEmitter.inc -gen-compress-inst-emitter)
 tablegen(LLVM RISCVGenDAGISel.inc -gen-dag-isel)
 tablegen(LLVM RISCVGenDisassemblerTables.inc -gen-disassembler)
+tablegen(LLVM RISCVGenGlobalISel.inc -gen-global-isel)
 tablegen(LLVM RISCVGenInstrInfo.inc -gen-instr-info)
 tablegen(LLVM RISCVGenMCCodeEmitter.inc -gen-emitter)
 tablegen(LLVM RISCVGenMCPseudoLowering.inc -gen-pseudo-lowering)
+tablegen(LLVM RISCVGenRegisterBank.inc -gen-register-bank)
 tablegen(LLVM RISCVGenRegisterInfo.inc -gen-register-info)
 tablegen(LLVM RISCVGenSubtargetInfo.inc -gen-subtarget)
 tablegen(LLVM RISCVGenSystemOperands.inc -gen-searchable-tables)
 
 add_public_tablegen_target(RISCVCommonTableGen)
 
 add_llvm_target(RISCVCodeGen
   RISCVAsmPrinter.cpp
+  RISCVCallLowering.cpp
   RISCVExpandPseudoInsts.cpp
   RISCVFrameLowering.cpp
   RISCVInstrInfo.cpp
+  RISCVInstructionSelector.cpp
   RISCVISelDAGToDAG.cpp
   RISCVISelLowering.cpp
+  RISCVLegalizerInfo.cpp
   RISCVMCInstLower.cpp
   RISCVMergeBaseOffset.cpp
+  RISCVRegisterBankInfo.cpp
   RISCVRegisterInfo.cpp
   RISCVSubtarget.cpp
   RISCVTargetMachine.cpp
   RISCVTargetObjectFile.cpp
   RISCVTargetTransformInfo.cpp
   )
 
 add_subdirectory(AsmParser)
 add_subdirectory(Disassembler)
 add_subdirectory(MCTargetDesc)
 add_subdirectory(TargetInfo)
 add_subdirectory(Utils)

llvm/lib/Target/RISCV/LLVMBuild.txt

 has_asmprinter = 1
 has_disassembler = 1
 
 [component_1]
 type = Library
 name = RISCVCodeGen
 parent = RISCV
 required_libraries = Analysis AsmPrinter Core CodeGen MC RISCVDesc
-  RISCVInfo RISCVUtils SelectionDAG Support Target
+  RISCVInfo RISCVUtils SelectionDAG Support Target GlobalISel
 add_to_library_groups = RISCV

llvm/lib/Target/RISCV/RISCV.h

 
 #ifndef LLVM_LIB_TARGET_RISCV_RISCV_H
 #define LLVM_LIB_TARGET_RISCV_RISCV_H
 
 #include "Utils/RISCVBaseInfo.h"
 #include "llvm/Target/TargetMachine.h"
 
 namespace llvm {
+class RISCVRegisterBankInfo;
+class RISCVSubtarget;
 class RISCVTargetMachine;
 class AsmPrinter;
 class FunctionPass;
+class InstructionSelector;
 class MCInst;
 class MCOperand;
 class MachineInstr;
 class MachineOperand;
 class PassRegistry;
 
 void LowerRISCVMachineInstrToMCInst(const MachineInstr *MI, MCInst &OutMI,
                                     const AsmPrinter &AP);
 bool LowerRISCVMachineOperandToMCOperand(const MachineOperand &MO,
                                          MCOperand &MCOp, const AsmPrinter &AP);
 
 FunctionPass *createRISCVISelDag(RISCVTargetMachine &TM);
 
 FunctionPass *createRISCVMergeBaseOffsetOptPass();
 void initializeRISCVMergeBaseOffsetOptPass(PassRegistry &);
 
 FunctionPass *createRISCVExpandPseudoPass();
 void initializeRISCVExpandPseudoPass(PassRegistry &);
+
+InstructionSelector *createRISCVInstructionSelector(const RISCVTargetMachine &,
+                                                    RISCVSubtarget &,
+                                                    RISCVRegisterBankInfo &);
 }
 
 #endif

llvm/lib/Target/RISCV/RISCV.td

 
 //===----------------------------------------------------------------------===//
 // Registers, calling conventions, instruction descriptions.
 //===----------------------------------------------------------------------===//
 
 include "RISCVRegisterInfo.td"
 include "RISCVCallingConv.td"
 include "RISCVInstrInfo.td"
+include "RISCVRegisterBanks.td"
 
 //===----------------------------------------------------------------------===//
 // RISC-V processors supported.
 //===----------------------------------------------------------------------===//
 
 def : ProcessorModel<"generic-rv32", NoSchedModel, []>;
 
 def : ProcessorModel<"generic-rv64", NoSchedModel, [Feature64Bit]>;

llvm/lib/Target/RISCV/RISCVCallLowering.h

+//===-- RISCVCallLowering.h - Call lowering ---------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// This file describes how to lower LLVM calls to machine code calls.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_RISCV_RISCVCALLLOWERING_H
+#define LLVM_LIB_TARGET_RISCV_RISCVCALLLOWERING_H
+
+#include "llvm/CodeGen/CallingConvLower.h"
+#include "llvm/CodeGen/GlobalISel/CallLowering.h"
+#include "llvm/CodeGen/ValueTypes.h"
+
+namespace llvm {
+
+class RISCVTargetLowering;
+
+class RISCVCallLowering : public CallLowering {
+
+public:
+  RISCVCallLowering(const RISCVTargetLowering &TLI);
+
+  bool lowerReturn(MachineIRBuilder &MIRBuiler, const Value *Val,
+                   ArrayRef<Register> VRegs) const override;
+
+  bool lowerFormalArguments(MachineIRBuilder &MIRBuilder, const Function &F,
+                            ArrayRef<ArrayRef<Register>> VRegs) const override;
+
+  bool lowerCall(MachineIRBuilder &MIRBuilder, CallingConv::ID CallConv,
+                 const MachineOperand &Callee, const ArgInfo &OrigRet,
+                 ArrayRef<ArgInfo> OrigArgs) const override;
+};
+
+} // end namespace llvm
+
+#endif // LLVM_LIB_TARGET_RISCV_RISCVCALLLOWERING_H

llvm/lib/Target/RISCV/RISCVCallLowering.cpp

+//===-- RISCVCallLowering.cpp - Call lowering -------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+/// \file
+/// This file implements the lowering of LLVM calls to machine code calls for
+/// GlobalISel.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVCallLowering.h"
+#include "RISCVISelLowering.h"
+#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
+
+using namespace llvm;
+
+RISCVCallLowering::RISCVCallLowering(const RISCVTargetLowering &TLI)
+    : CallLowering(&TLI) {}
+
+bool RISCVCallLowering::lowerReturn(MachineIRBuilder &MIRBuilder,
+                                    const Value *Val,
+                                    ArrayRef<Register> VRegs) const {
+
+  MachineInstrBuilder Ret = MIRBuilder.buildInstrNoInsert(RISCV::PseudoRET);
+
+  if (Val != nullptr) {
+    return false;
+  }
+  MIRBuilder.insertInstr(Ret);
+  return true;
+}
+
+bool RISCVCallLowering::lowerFormalArguments(
+    MachineIRBuilder &MIRBuilder, const Function &F,
+    ArrayRef<ArrayRef<Register>> VRegs) const {
+
+  if (F.arg_empty())
+    return true;
+
+  return false;
+}
+
+bool RISCVCallLowering::lowerCall(MachineIRBuilder &MIRBuilder,
+                                  CallingConv::ID CallConv,
+                                  const MachineOperand &Callee,
+                                  const ArgInfo &OrigRet,
+                                  ArrayRef<ArgInfo> OrigArgs) const {
+
+  return false;
+}

llvm/lib/Target/RISCV/RISCVInstructionSelector.cpp

+//===-- RISCVInstructionSelector.cpp -----------------------------*- C++ -*-==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the targeting of the InstructionSelector class for
+/// RISCV.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#include "RISCVRegisterBankInfo.h"
+#include "RISCVSubtarget.h"
+#include "RISCVTargetMachine.h"
+#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
+#include "llvm/CodeGen/GlobalISel/InstructionSelectorImpl.h"
+#include "llvm/Support/Debug.h"
+
+#define DEBUG_TYPE "riscv-isel"
+
+using namespace llvm;
+
+#define GET_GLOBALISEL_PREDICATE_BITSET
+#include "RISCVGenGlobalISel.inc"
+#undef GET_GLOBALISEL_PREDICATE_BITSET
+
+namespace {
+
+class RISCVInstructionSelector : public InstructionSelector {
+public:
+  RISCVInstructionSelector(const RISCVTargetMachine &TM,
+                           const RISCVSubtarget &STI,
+                           const RISCVRegisterBankInfo &RBI);
+
+  bool select(MachineInstr &I, CodeGenCoverage &CoverageInfo) const override;
+  static const char *getName() { return DEBUG_TYPE; }
+
+private:
+  bool selectImpl(MachineInstr &I, CodeGenCoverage &CoverageInfo) const;
+
+  const RISCVTargetMachine &TM;
+  const RISCVSubtarget &STI;
+  const RISCVInstrInfo &TII;
+  const RISCVRegisterInfo &TRI;
+  const RISCVRegisterBankInfo &RBI;
+
+  // FIXME: This is necessary because DAGISel uses "Subtarget->" and GlobalISel
+  // uses "STI." in the code generated by TableGen. We need to unify the name of
+  // Subtarget variable.
+  const RISCVSubtarget *Subtarget = &STI;
+
+#define GET_GLOBALISEL_PREDICATES_DECL
+#include "RISCVGenGlobalISel.inc"
+#undef GET_GLOBALISEL_PREDICATES_DECL
+
+#define GET_GLOBALISEL_TEMPORARIES_DECL
+#include "RISCVGenGlobalISel.inc"
+#undef GET_GLOBALISEL_TEMPORARIES_DECL
+};
+
+} // end anonymous namespace
+
+#define GET_GLOBALISEL_IMPL
+#include "RISCVGenGlobalISel.inc"
+#undef GET_GLOBALISEL_IMPL
+
+RISCVInstructionSelector::RISCVInstructionSelector(
+    const RISCVTargetMachine &TM, const RISCVSubtarget &STI,
+    const RISCVRegisterBankInfo &RBI)
+    : InstructionSelector(), TM(TM), STI(STI), TII(*STI.getInstrInfo()),
+      TRI(*STI.getRegisterInfo()), RBI(RBI),
+
+#define GET_GLOBALISEL_PREDICATES_INIT
+#include "RISCVGenGlobalISel.inc"
+#undef GET_GLOBALISEL_PREDICATES_INIT
+#define GET_GLOBALISEL_TEMPORARIES_INIT
+#include "RISCVGenGlobalISel.inc"
+#undef GET_GLOBALISEL_TEMPORARIES_INIT
+{
+}
+
+bool RISCVInstructionSelector::select(MachineInstr &I,
+                                      CodeGenCoverage &CoverageInfo) const {
+
+  if (!isPreISelGenericOpcode(I.getOpcode())) {
+    // Certain non-generic instructions also need some special handling.
+    return true;
+  }
+
+  if (selectImpl(I, CoverageInfo))
+    return true;
+
+  return false;
+}
+
+namespace llvm {
+InstructionSelector *
+createRISCVInstructionSelector(const RISCVTargetMachine &TM,
+                               RISCVSubtarget &Subtarget,
+                               RISCVRegisterBankInfo &RBI) {
+  return new RISCVInstructionSelector(TM, Subtarget, RBI);
+}
+} // end namespace llvm

llvm/lib/Target/RISCV/RISCVLegalizerInfo.h

+//===-- RISCVLegalizerInfo.h ------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file declares the targeting of the Machinelegalizer class for RISCV.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_RISCV_RISCVMACHINELEGALIZER_H
+#define LLVM_LIB_TARGET_RISCV_RISCVMACHINELEGALIZER_H
+
+#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
+
+namespace llvm {
+
+class RISCVSubtarget;
+
+/// This class provides the information for the target register banks.
+class RISCVLegalizerInfo : public LegalizerInfo {
+public:
+  RISCVLegalizerInfo(const RISCVSubtarget &ST);
+};
+} // end namespace llvm
+#endif

llvm/lib/Target/RISCV/RISCVLegalizerInfo.cpp

+//===-- RISCVLegalizerInfo.cpp ----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the targeting of the Machinelegalizer class for RISCV.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#include "RISCVLegalizerInfo.h"
+#include "llvm/CodeGen/TargetOpcodes.h"
+#include "llvm/CodeGen/ValueTypes.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Type.h"
+
+using namespace llvm;
+
+RISCVLegalizerInfo::RISCVLegalizerInfo(const RISCVSubtarget &ST) {
+  computeTables();
+}

llvm/lib/Target/RISCV/RISCVRegisterBankInfo.h

+//===-- RISCVRegisterBankInfo.h ---------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file declares the targeting of the RegisterBankInfo class for RISCV.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_RISCV_RISCVREGISTERBANKINFO_H
+#define LLVM_LIB_TARGET_RISCV_RISCVREGISTERBANKINFO_H
+
+#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
+
+#define GET_REGBANK_DECLARATIONS
+#include "RISCVGenRegisterBank.inc"
+
+namespace llvm {
+
+class TargetRegisterInfo;
+
+class RISCVGenRegisterBankInfo : public RegisterBankInfo {
+protected:
+#define GET_TARGET_REGBANK_CLASS
+#include "RISCVGenRegisterBank.inc"
+};
+
+/// This class provides the information for the target register banks.
+class RISCVRegisterBankInfo final : public RISCVGenRegisterBankInfo {
+public:
+  RISCVRegisterBankInfo(const TargetRegisterInfo &TRI);
+};
+} // end namespace llvm
+#endif

llvm/lib/Target/RISCV/RISCVRegisterBankInfo.cpp

+//===-- RISCVRegisterBankInfo.cpp -------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the targeting of the RegisterBankInfo class for RISCV.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#include "RISCVRegisterBankInfo.h"
+#include "MCTargetDesc/RISCVMCTargetDesc.h"
+#include "llvm/CodeGen/GlobalISel/RegisterBank.h"
+#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+
+#define GET_TARGET_REGBANK_IMPL
+#include "RISCVGenRegisterBank.inc"
+
+using namespace llvm;
+
+RISCVRegisterBankInfo::RISCVRegisterBankInfo(const TargetRegisterInfo &TRI)
+    : RISCVGenRegisterBankInfo() {}

llvm/lib/Target/RISCV/RISCVRegisterBanks.td

+//=-- RISCVRegisterBank.td - Describe the RISCV Banks --------*- tablegen -*-=//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+//
+//===----------------------------------------------------------------------===//
+
+/// General Purpose Registers: X.
+def GPRRegBank : RegisterBank<"GPRB", [GPR]>;

llvm/lib/Target/RISCV/RISCVSubtarget.h

 
 #ifndef LLVM_LIB_TARGET_RISCV_RISCVSUBTARGET_H
 #define LLVM_LIB_TARGET_RISCV_RISCVSUBTARGET_H
 
 #include "RISCVFrameLowering.h"
 #include "RISCVISelLowering.h"
 #include "RISCVInstrInfo.h"
 #include "Utils/RISCVBaseInfo.h"
+#include "llvm/CodeGen/GlobalISel/CallLowering.h"
+#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
+#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
+#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
 #include "llvm/CodeGen/SelectionDAGTargetInfo.h"
 #include "llvm/CodeGen/TargetSubtargetInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/Target/TargetMachine.h"
 
 #define GET_SUBTARGETINFO_HEADER
 #include "RISCVGenSubtargetInfo.inc"
 
public:
   bool hasStdExtD() const { return HasStdExtD; }
   bool hasStdExtC() const { return HasStdExtC; }
   bool is64Bit() const { return HasRV64; }
   bool isRV32E() const { return IsRV32E; }
   bool enableLinkerRelax() const { return EnableLinkerRelax; }
   MVT getXLenVT() const { return XLenVT; }
   unsigned getXLen() const { return XLen; }
   RISCVABI::ABI getTargetABI() const { return TargetABI; }
+
+protected:
+  // GlobalISel related APIs.
+  std::unique_ptr<CallLowering> CallLoweringInfo;
+  std::unique_ptr<InstructionSelector> InstSelector;
+  std::unique_ptr<LegalizerInfo> Legalizer;
+  std::unique_ptr<RegisterBankInfo> RegBankInfo;
+
+public:
+  const CallLowering *getCallLowering() const override;
+  const InstructionSelector *getInstructionSelector() const override;
+  const LegalizerInfo *getLegalizerInfo() const override;
+  const RegisterBankInfo *getRegBankInfo() const override;
 };
 } // End llvm namespace
 
 #endif

llvm/lib/Target/RISCV/RISCVSubtarget.cpp

 //===-- RISCVSubtarget.cpp - RISCV Subtarget Information ------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the RISCV specific subclass of TargetSubtargetInfo.
 //
 //===----------------------------------------------------------------------===//
 
 #include "RISCVSubtarget.h"
 #include "RISCV.h"
+#include "RISCVCallLowering.h"
 #include "RISCVFrameLowering.h"
+#include "RISCVLegalizerInfo.h"
+#include "RISCVRegisterBankInfo.h"
+#include "RISCVTargetMachine.h"
 #include "llvm/Support/TargetRegistry.h"
 
 using namespace llvm;
 
 #define DEBUG_TYPE "riscv-subtarget"
 
 #define GET_SUBTARGETINFO_TARGET_DESC
 #define GET_SUBTARGETINFO_CTOR
RISCVSubtarget &RISCVSubtarget::initializeSubtargetDependencies(
   RISCVFeatures::validate(TT, getFeatureBits());
   return *this;
 }
 
 RISCVSubtarget::RISCVSubtarget(const Triple &TT, StringRef CPU, StringRef FS,
                                StringRef ABIName, const TargetMachine &TM)
     : RISCVGenSubtargetInfo(TT, CPU, FS),
       FrameLowering(initializeSubtargetDependencies(TT, CPU, FS, ABIName)),
-      InstrInfo(), RegInfo(getHwMode()), TLInfo(TM, *this) {}
+      InstrInfo(), RegInfo(getHwMode()), TLInfo(TM, *this) {
+  CallLoweringInfo.reset(new RISCVCallLowering(*getTargetLowering()));
+  Legalizer.reset(new RISCVLegalizerInfo(*this));
+
+  auto *RBI = new RISCVRegisterBankInfo(*getRegisterInfo());
+  RegBankInfo.reset(RBI);
+  InstSelector.reset(createRISCVInstructionSelector(
+      *static_cast<const RISCVTargetMachine *>(&TM), *this, *RBI));
+}
+
+const CallLowering *RISCVSubtarget::getCallLowering() const {
+  return CallLoweringInfo.get();
+}
+
+const InstructionSelector *RISCVSubtarget::getInstructionSelector() const {
+  return InstSelector.get();
+}
+
+const LegalizerInfo *RISCVSubtarget::getLegalizerInfo() const {
+  return Legalizer.get();
+}
+
+const RegisterBankInfo *RISCVSubtarget::getRegBankInfo() const {
+  return RegBankInfo.get();
+}

llvm/lib/Target/RISCV/RISCVTargetMachine.cpp

 
 #include "RISCVTargetMachine.h"
 #include "RISCV.h"
 #include "RISCVTargetObjectFile.h"
 #include "RISCVTargetTransformInfo.h"
 #include "TargetInfo/RISCVTargetInfo.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
+#include "llvm/CodeGen/GlobalISel/IRTranslator.h"
+#include "llvm/CodeGen/GlobalISel/InstructionSelect.h"
+#include "llvm/CodeGen/GlobalISel/Legalizer.h"
+#include "llvm/CodeGen/GlobalISel/RegBankSelect.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/CodeGen/TargetLoweringObjectFileImpl.h"
 #include "llvm/CodeGen/TargetPassConfig.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/Support/FormattedStream.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Target/TargetOptions.h"
 using namespace llvm;
 
 extern "C" void LLVMInitializeRISCVTarget() {
   RegisterTargetMachine<RISCVTargetMachine> X(getTheRISCV32Target());
   RegisterTargetMachine<RISCVTargetMachine> Y(getTheRISCV64Target());
   auto PR = PassRegistry::getPassRegistry();
+  initializeGlobalISel(*PR);
   initializeRISCVExpandPseudoPass(*PR);
 }
 
 static StringRef computeDataLayout(const Triple &TT) {
   if (TT.isArch64Bit()) {
     return "e-m:e-p:64:64-i64:64-i128:128-n64-S128";
   } else {
     assert(TT.isArch32Bit() && "only RV32 and RV64 are currently supported");
RISCVPassConfig(RISCVTargetMachine &TM, PassManagerBase &PM)
       : TargetPassConfig(TM, PM) {}
 
   RISCVTargetMachine &getRISCVTargetMachine() const {
     return getTM<RISCVTargetMachine>();
   }
 
   void addIRPasses() override;
   bool addInstSelector() override;
+  bool addIRTranslator() override;
+  bool addLegalizeMachineIR() override;
+  bool addRegBankSelect() override;
+  bool addGlobalInstructionSelect() override;
   void addPreEmitPass() override;
   void addPreEmitPass2() override;
   void addPreRegAlloc() override;
 };
 }
 
 TargetPassConfig *RISCVTargetMachine::createPassConfig(PassManagerBase &PM) {
   return new RISCVPassConfig(*this, PM);
 }
 
 void RISCVPassConfig::addIRPasses() {
   addPass(createAtomicExpandPass());
   TargetPassConfig::addIRPasses();
 }
 
 bool RISCVPassConfig::addInstSelector() {
   addPass(createRISCVISelDag(getRISCVTargetMachine()));
 
   return false;
 }
 
+bool RISCVPassConfig::addIRTranslator() {
+  addPass(new IRTranslator());
+  return false;
+}
+
+bool RISCVPassConfig::addLegalizeMachineIR() {
+  addPass(new Legalizer());
+  return false;
+}
+
+bool RISCVPassConfig::addRegBankSelect() {
+  addPass(new RegBankSelect());
+  return false;
+}
+
+bool RISCVPassConfig::addGlobalInstructionSelect() {
+  addPass(new InstructionSelect());
+  return false;
+}
+
 void RISCVPassConfig::addPreEmitPass() { addPass(&BranchRelaxationPassID); }
 
 void RISCVPassConfig::addPreEmitPass2() {
   // Schedule the expansion of AMOs at the last possible moment, avoiding the
   // possibility for other passes to break the requirements for forward
   // progress in the LR/SC block.
   addPass(createRISCVExpandPseudoPass());
 }
 
 void RISCVPassConfig::addPreRegAlloc() {
   addPass(createRISCVMergeBaseOffsetOptPass());
 }

llvm/test/CodeGen/RISCV/GlobalISel/calllowering-ret.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -global-isel -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV32I %s
+; RUN: llc -mtriple=riscv64 -global-isel -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV64I %s
+
+define void @foo() {
+  ; RV32I-LABEL: foo
+  ; RV32I:       # %bb.0: # %entry
+  ; RV32I:         ret
+
+  ; RV64I-LABEL: foo
+  ; RV64I:       # %bb.0: # %entry
+  ; RV64I:         ret
+entry:
+  ret void
+}

llvm/test/CodeGen/RISCV/GlobalISel/irtranslator-calllowering.ll

+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc -mtriple=riscv32 -global-isel -stop-after=irtranslator -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV32I %s
+; RUN: llc -mtriple=riscv64 -global-isel -stop-after=irtranslator -verify-machineinstrs < %s \
+; RUN:   | FileCheck -check-prefix=RV64I %s
+
+define void @foo() {
+  ; RV32I-LABEL: name: foo
+  ; RV32I: bb.1.entry:
+  ; RV32I-NEXT:   PseudoRET
+
+  ; RV64I-LABEL: name: foo
+  ; RV64I: bb.1.entry:
+  ; RV64I-NEXT:   PseudoRET
+entry:
+  ret void
+}