[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

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

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

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

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.

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;
+}

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

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

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();
+}

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

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() {}

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

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]>;