[RISCV GlobalISel] Adding initial GlobalISel infrastructure

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

Patch by Andrew Wei

Reviewers: asb, sabuasal, apazos, lenary, simoncook, lewis-revill, edward-jones, rogfer01, xiangzhai, rovka, Petar.Avramovic, mgorny, dsanders

Reviewed By: dsanders

Subscribers: pzheng, s.egerton, dsanders, hiraditya, rbar, johnrusso, niosHD, kito-cheng, shiva0217, jrtc27, MaskRay, zzheng, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, psnobl, benna, Jim, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65219

llvm-svn: 369467

15 files changed, 412 insertions, 2 deletions

diff --git a/llvm/lib/Target/RISCV/CMakeLists.txt b/llvm/lib/Target/RISCV/CMakeLists.txt
index 5cdaf344703..31a82be1981 100644
--- a/llvm/lib/Target/RISCV/CMakeLists.txt
+++ b/llvm/lib/Target/RISCV/CMakeLists.txt
@@ -5,9 +5,11 @@ 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)
@@ -16,13 +18,17 @@ 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
diff --git a/llvm/lib/Target/RISCV/LLVMBuild.txt b/llvm/lib/Target/RISCV/LLVMBuild.txt
index 9526f8e49bb..38012b2f27f 100644
--- a/llvm/lib/Target/RISCV/LLVMBuild.txt
+++ b/llvm/lib/Target/RISCV/LLVMBuild.txt
@@ -30,5 +30,5 @@ 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
diff --git a/llvm/lib/Target/RISCV/RISCV.h b/llvm/lib/Target/RISCV/RISCV.h
index 834a1d17114..f23f742a478 100644
--- a/llvm/lib/Target/RISCV/RISCV.h
+++ b/llvm/lib/Target/RISCV/RISCV.h
@@ -18,9 +18,12 @@
 #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;
@@ -39,6 +42,10 @@ void initializeRISCVMergeBaseOffsetOptPass(PassRegistry &);
 
 FunctionPass *createRISCVExpandPseudoPass();
 void initializeRISCVExpandPseudoPass(PassRegistry &);
+
+InstructionSelector *createRISCVInstructionSelector(const RISCVTargetMachine &,
+                                                    RISCVSubtarget &,
+                                                    RISCVRegisterBankInfo &);
 }
 
 #endif
diff --git a/llvm/lib/Target/RISCV/RISCV.td b/llvm/lib/Target/RISCV/RISCV.td
index e19b70b8e70..a4775dca7e0 100644
--- a/llvm/lib/Target/RISCV/RISCV.td
+++ b/llvm/lib/Target/RISCV/RISCV.td
@@ -77,6 +77,7 @@ include "RISCVSystemOperands.td"
 include "RISCVRegisterInfo.td"
 include "RISCVCallingConv.td"
 include "RISCVInstrInfo.td"
+include "RISCVRegisterBanks.td"
 
 //===----------------------------------------------------------------------===//
 // RISC-V processors supported.
diff --git a/llvm/lib/Target/RISCV/RISCVCallLowering.cpp b/llvm/lib/Target/RISCV/RISCVCallLowering.cpp
new file mode 100644
index 00000000000..c63a84739c4
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVCallLowering.cpp
@@ -0,0 +1,50 @@
+//===-- 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,
+                                  CallLoweringInfo &Info) const {
+  return false;
+}
diff --git a/llvm/lib/Target/RISCV/RISCVCallLowering.h b/llvm/lib/Target/RISCV/RISCVCallLowering.h
new file mode 100644
index 00000000000..7ce074a61f0
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVCallLowering.h
@@ -0,0 +1,42 @@
+//===-- 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,
+                 CallLoweringInfo &Info) const override;
+};
+
+} // end namespace llvm
+
+#endif // LLVM_LIB_TARGET_RISCV_RISCVCALLLOWERING_H
diff --git a/llvm/lib/Target/RISCV/RISCVInstructionSelector.cpp b/llvm/lib/Target/RISCV/RISCVInstructionSelector.cpp
new file mode 100644
index 00000000000..5bd09a54611
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVInstructionSelector.cpp
@@ -0,0 +1,103 @@
+//===-- 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) override;
+  static const char *getName() { return DEBUG_TYPE; }
+
+private:
+  bool selectImpl(MachineInstr &I, CodeGenCoverage &CoverageInfo) const;
+
+  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(), 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) {
+
+  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
diff --git a/llvm/lib/Target/RISCV/RISCVLegalizerInfo.cpp b/llvm/lib/Target/RISCV/RISCVLegalizerInfo.cpp
new file mode 100644
index 00000000000..c92f4a3ee17
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVLegalizerInfo.cpp
@@ -0,0 +1,23 @@
+//===-- 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();
+}
diff --git a/llvm/lib/Target/RISCV/RISCVLegalizerInfo.h b/llvm/lib/Target/RISCV/RISCVLegalizerInfo.h
new file mode 100644
index 00000000000..f2c2b9a3fd4
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVLegalizerInfo.h
@@ -0,0 +1,28 @@
+//===-- 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
diff --git a/llvm/lib/Target/RISCV/RISCVRegisterBankInfo.cpp b/llvm/lib/Target/RISCV/RISCVRegisterBankInfo.cpp
new file mode 100644
index 00000000000..bd3b95a98b9
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVRegisterBankInfo.cpp
@@ -0,0 +1,26 @@
+//===-- 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() {}
diff --git a/llvm/lib/Target/RISCV/RISCVRegisterBankInfo.h b/llvm/lib/Target/RISCV/RISCVRegisterBankInfo.h
new file mode 100644
index 00000000000..05fac992734
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVRegisterBankInfo.h
@@ -0,0 +1,37 @@
+//===-- 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
diff --git a/llvm/lib/Target/RISCV/RISCVRegisterBanks.td b/llvm/lib/Target/RISCV/RISCVRegisterBanks.td
new file mode 100644
index 00000000000..400b65a1bf9
--- /dev/null
+++ b/llvm/lib/Target/RISCV/RISCVRegisterBanks.td
@@ -0,0 +1,13 @@
+//=-- 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]>;
diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.cpp b/llvm/lib/Target/RISCV/RISCVSubtarget.cpp
index 6902ed75d85..5673f2205a6 100644
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.cpp
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.cpp
@@ -12,7 +12,11 @@
 
 #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;
@@ -47,4 +51,28 @@ 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();
+}
+
+InstructionSelector *RISCVSubtarget::getInstructionSelector() const {
+  return InstSelector.get();
+}
+
+const LegalizerInfo *RISCVSubtarget::getLegalizerInfo() const {
+  return Legalizer.get();
+}
+
+const RegisterBankInfo *RISCVSubtarget::getRegBankInfo() const {
+  return RegBankInfo.get();
+}
diff --git a/llvm/lib/Target/RISCV/RISCVSubtarget.h b/llvm/lib/Target/RISCV/RISCVSubtarget.h
index 106ff49f021..12ba5f844b0 100644
--- a/llvm/lib/Target/RISCV/RISCVSubtarget.h
+++ b/llvm/lib/Target/RISCV/RISCVSubtarget.h
@@ -17,6 +17,10 @@
 #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"
@@ -86,6 +90,19 @@ public:
   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;
+  InstructionSelector *getInstructionSelector() const override;
+  const LegalizerInfo *getLegalizerInfo() const override;
+  const RegisterBankInfo *getRegBankInfo() const override;
 };
 } // End llvm namespace
 
diff --git a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
index c9614cca636..5ffc6eda6bd 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetMachine.cpp
@@ -17,6 +17,10 @@
 #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"
@@ -30,6 +34,7 @@ extern "C" void LLVMInitializeRISCVTarget() {
   RegisterTargetMachine<RISCVTargetMachine> X(getTheRISCV32Target());
   RegisterTargetMachine<RISCVTargetMachine> Y(getTheRISCV64Target());
   auto PR = PassRegistry::getPassRegistry();
+  initializeGlobalISel(*PR);
   initializeRISCVExpandPseudoPass(*PR);
 }
 
@@ -80,6 +85,10 @@ public:
 
   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;
@@ -101,6 +110,26 @@ bool RISCVPassConfig::addInstSelector() {
   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() {