0006-RISCV-Add-bare-bones-RISC-V-MCTargetDesc.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Alex Bradbury <asb@lowrisc.org>
Subject: [RISCV] Add bare-bones RISC-V MCTargetDesc

This is enough to compile and link but doesn't yet do anything particularly
useful. Once an ASM parser and printer are added in the next patch, the whole
thing can be tested.

Differential Revision: https://reviews.llvm.org/D23562
Upstream commit: https://reviews.llvm.org/rL285770
Upstream commit: https://reviews.llvm.org/rL285806

NOTE: This patch has been updated since being committed upstream.
---
 lib/Target/RISCV/CMakeLists.txt                    |  2 +
 lib/Target/RISCV/LLVMBuild.txt                     |  2 +-
 lib/Target/RISCV/MCTargetDesc/CMakeLists.txt       |  7 ++
 lib/Target/RISCV/MCTargetDesc/LLVMBuild.txt        | 23 ++++++
 lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp  | 95 ++++++++++++++++++++++
 .../RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp    | 50 ++++++++++++
 lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.cpp   | 25 ++++++
 lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.h     | 31 +++++++
 .../RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp      | 91 +++++++++++++++++++++
 .../RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp       | 58 +++++++++++++
 lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h  | 59 ++++++++++++++
 lib/Target/RISCV/RISCVTargetMachine.h              |  3 +-
 lib/Target/RISCV/TargetInfo/RISCVTargetInfo.cpp    |  5 --
 13 files changed, 443 insertions(+), 8 deletions(-)
 create mode 100644 lib/Target/RISCV/MCTargetDesc/CMakeLists.txt
 create mode 100644 lib/Target/RISCV/MCTargetDesc/LLVMBuild.txt
 create mode 100644 lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
 create mode 100644 lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
 create mode 100644 lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.cpp
 create mode 100644 lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.h
 create mode 100644 lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp
 create mode 100644 lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp
 create mode 100644 lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h

diff --git a/lib/Target/RISCV/CMakeLists.txt b/lib/Target/RISCV/CMakeLists.txt
index 5a98f9f719d..c8887548b91 100644
--- a/lib/Target/RISCV/CMakeLists.txt
+++ b/lib/Target/RISCV/CMakeLists.txt
@@ -2,6 +2,7 @@ set(LLVM_TARGET_DEFINITIONS RISCV.td)
 
 tablegen(LLVM RISCVGenRegisterInfo.inc -gen-register-info)
 tablegen(LLVM RISCVGenInstrInfo.inc -gen-instr-info)
+tablegen(LLVM RISCVGenMCCodeEmitter.inc -gen-emitter)
 
 add_public_tablegen_target(RISCVCommonTableGen)
 
@@ -10,3 +11,4 @@ add_llvm_target(RISCVCodeGen
   )
 
 add_subdirectory(TargetInfo)
+add_subdirectory(MCTargetDesc)
diff --git a/lib/Target/RISCV/LLVMBuild.txt b/lib/Target/RISCV/LLVMBuild.txt
index e5e5692490c..9ba5fec928f 100644
--- a/lib/Target/RISCV/LLVMBuild.txt
+++ b/lib/Target/RISCV/LLVMBuild.txt
@@ -16,7 +16,7 @@
 ;===------------------------------------------------------------------------===;
 
 [common]
-subdirectories = TargetInfo
+subdirectories = TargetInfo MCTargetDesc
 
 [component_0]
 type = TargetGroup
diff --git a/lib/Target/RISCV/MCTargetDesc/CMakeLists.txt b/lib/Target/RISCV/MCTargetDesc/CMakeLists.txt
new file mode 100644
index 00000000000..d79de74f7cf
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/CMakeLists.txt
@@ -0,0 +1,7 @@
+add_llvm_library(LLVMRISCVDesc
+  RISCVAsmBackend.cpp
+  RISCVELFObjectWriter.cpp
+  RISCVMCAsmInfo.cpp
+  RISCVMCTargetDesc.cpp
+  RISCVMCCodeEmitter.cpp
+)
diff --git a/lib/Target/RISCV/MCTargetDesc/LLVMBuild.txt b/lib/Target/RISCV/MCTargetDesc/LLVMBuild.txt
new file mode 100644
index 00000000000..e48f04963ff
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/LLVMBuild.txt
@@ -0,0 +1,23 @@
+;===- ./lib/Target/RISCV/MCTargetDesc/LLVMBuild.txt ------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = RISCVDesc
+parent = RISCV
+required_libraries = MC RISCVInfo Support
+add_to_library_groups = RISCV
diff --git a/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp b/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
new file mode 100644
index 00000000000..cb794c5a4e3
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -0,0 +1,95 @@
+//===-- RISCVAsmBackend.cpp - RISCV Assembler Backend ---------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/RISCVMCTargetDesc.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCAssembler.h"
+#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCFixupKindInfo.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+namespace {
+class RISCVAsmBackend : public MCAsmBackend {
+  uint8_t OSABI;
+  bool Is64Bit;
+
+public:
+  RISCVAsmBackend(uint8_t OSABI, bool Is64Bit)
+      : MCAsmBackend(), OSABI(OSABI), Is64Bit(Is64Bit) {}
+  ~RISCVAsmBackend() override {}
+
+  void applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
+                  const MCValue &Target, MutableArrayRef<char> Data,
+                  uint64_t Value, bool IsResolved) const override;
+
+  std::unique_ptr<MCObjectWriter>
+  createObjectWriter(raw_pwrite_stream &OS) const override;
+
+  bool fixupNeedsRelaxation(const MCFixup &Fixup, uint64_t Value,
+                            const MCRelaxableFragment *DF,
+                            const MCAsmLayout &Layout) const override {
+    return false;
+  }
+
+  unsigned getNumFixupKinds() const override { return 1; }
+
+  bool mayNeedRelaxation(const MCInst &Inst) const override { return false; }
+
+  void relaxInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
+                        MCInst &Res) const override {
+
+    report_fatal_error("RISCVAsmBackend::relaxInstruction() unimplemented");
+  }
+
+  bool writeNopData(uint64_t Count, MCObjectWriter *OW) const override;
+};
+
+bool RISCVAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
+  // Once support for the compressed instruction set is added, we will be able
+  // to conditionally support 16-bit NOPs
+  if ((Count % 4) != 0)
+    return false;
+
+  // The canonical nop on RISC-V is addi x0, x0, 0
+  for (uint64_t i = 0; i < Count; i += 4)
+    OW->write32(0x13);
+
+  return true;
+}
+
+void RISCVAsmBackend::applyFixup(const MCAssembler &Asm, const MCFixup &Fixup,
+                                 const MCValue &Target,
+                                 MutableArrayRef<char> Data, uint64_t Value,
+                                 bool IsResolved) const {
+  return;
+}
+
+std::unique_ptr<MCObjectWriter>
+RISCVAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
+  return createRISCVELFObjectWriter(OS, OSABI, Is64Bit);
+}
+
+} // end anonymous namespace
+
+MCAsmBackend *llvm::createRISCVAsmBackend(const Target &T,
+                                          const MCSubtargetInfo &STI,
+                                          const MCRegisterInfo &MRI,
+                                          const MCTargetOptions &Options) {
+  const Triple &TT = STI.getTargetTriple();
+  uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
+  return new RISCVAsmBackend(OSABI, TT.isArch64Bit());
+}
diff --git a/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp b/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
new file mode 100644
index 00000000000..445cdfd0d20
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/RISCVELFObjectWriter.cpp
@@ -0,0 +1,50 @@
+//===-- RISCVELFObjectWriter.cpp - RISCV ELF Writer -----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/RISCVMCTargetDesc.h"
+#include "llvm/MC/MCELFObjectWriter.h"
+#include "llvm/MC/MCFixup.h"
+#include "llvm/MC/MCObjectWriter.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace llvm;
+
+namespace {
+class RISCVELFObjectWriter : public MCELFObjectTargetWriter {
+public:
+  RISCVELFObjectWriter(uint8_t OSABI, bool Is64Bit);
+
+  ~RISCVELFObjectWriter() override;
+
+protected:
+  unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
+                        const MCFixup &Fixup, bool IsPCRel) const override;
+};
+}
+
+RISCVELFObjectWriter::RISCVELFObjectWriter(uint8_t OSABI, bool Is64Bit)
+    : MCELFObjectTargetWriter(Is64Bit, OSABI, ELF::EM_RISCV,
+                              /*HasRelocationAddend*/ true) {}
+
+RISCVELFObjectWriter::~RISCVELFObjectWriter() {}
+
+unsigned RISCVELFObjectWriter::getRelocType(MCContext &Ctx,
+                                            const MCValue &Target,
+                                            const MCFixup &Fixup,
+                                            bool IsPCRel) const {
+  report_fatal_error("invalid fixup kind!");
+}
+
+std::unique_ptr<MCObjectWriter>
+llvm::createRISCVELFObjectWriter(raw_pwrite_stream &OS, uint8_t OSABI,
+                                 bool Is64Bit) {
+  return createELFObjectWriter(
+      llvm::make_unique<RISCVELFObjectWriter>(OSABI, Is64Bit), OS,
+      /*IsLittleEndian=*/true);
+}
diff --git a/lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.cpp b/lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.cpp
new file mode 100644
index 00000000000..d622911e92c
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.cpp
@@ -0,0 +1,25 @@
+//===-- RISCVMCAsmInfo.cpp - RISCV Asm properties -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the declarations of the RISCVMCAsmInfo properties.
+//
+//===----------------------------------------------------------------------===//
+
+#include "RISCVMCAsmInfo.h"
+#include "llvm/ADT/Triple.h"
+using namespace llvm;
+
+void RISCVMCAsmInfo::anchor() {}
+
+RISCVMCAsmInfo::RISCVMCAsmInfo(const Triple &TT) {
+  CodePointerSize = CalleeSaveStackSlotSize = TT.isArch64Bit() ? 8 : 4;
+  CommentString = "#";
+  AlignmentIsInBytes = false;
+  SupportsDebugInformation = true;
+}
diff --git a/lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.h b/lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.h
new file mode 100644
index 00000000000..901a1eba8af
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/RISCVMCAsmInfo.h
@@ -0,0 +1,31 @@
+//===-- RISCVMCAsmInfo.h - RISCV Asm Info ----------------------*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the declaration of the RISCVMCAsmInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVMCASMINFO_H
+#define LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVMCASMINFO_H
+
+#include "llvm/MC/MCAsmInfoELF.h"
+
+namespace llvm {
+class Triple;
+
+class RISCVMCAsmInfo : public MCAsmInfoELF {
+  void anchor() override;
+
+public:
+  explicit RISCVMCAsmInfo(const Triple &TargetTriple);
+};
+
+} // namespace llvm
+
+#endif
diff --git a/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp b/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp
new file mode 100644
index 00000000000..9309d493cef
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/RISCVMCCodeEmitter.cpp
@@ -0,0 +1,91 @@
+//===-- RISCVMCCodeEmitter.cpp - Convert RISCV code to machine code -------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the RISCVMCCodeEmitter class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/RISCVMCTargetDesc.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/Support/EndianStream.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "mccodeemitter"
+
+STATISTIC(MCNumEmitted, "Number of MC instructions emitted");
+
+namespace {
+class RISCVMCCodeEmitter : public MCCodeEmitter {
+  RISCVMCCodeEmitter(const RISCVMCCodeEmitter &) = delete;
+  void operator=(const RISCVMCCodeEmitter &) = delete;
+  MCContext &Ctx;
+
+public:
+  RISCVMCCodeEmitter(MCContext &ctx) : Ctx(ctx) {}
+
+  ~RISCVMCCodeEmitter() override {}
+
+  void encodeInstruction(const MCInst &MI, raw_ostream &OS,
+                         SmallVectorImpl<MCFixup> &Fixups,
+                         const MCSubtargetInfo &STI) const override;
+
+  /// TableGen'erated function for getting the binary encoding for an
+  /// instruction.
+  uint64_t getBinaryCodeForInstr(const MCInst &MI,
+                                 SmallVectorImpl<MCFixup> &Fixups,
+                                 const MCSubtargetInfo &STI) const;
+
+  /// Return binary encoding of operand. If the machine operand requires
+  /// relocation, record the relocation and return zero.
+  unsigned getMachineOpValue(const MCInst &MI, const MCOperand &MO,
+                             SmallVectorImpl<MCFixup> &Fixups,
+                             const MCSubtargetInfo &STI) const;
+};
+} // end anonymous namespace
+
+MCCodeEmitter *llvm::createRISCVMCCodeEmitter(const MCInstrInfo &MCII,
+                                              const MCRegisterInfo &MRI,
+                                              MCContext &Ctx) {
+  return new RISCVMCCodeEmitter(Ctx);
+}
+
+void RISCVMCCodeEmitter::encodeInstruction(const MCInst &MI, raw_ostream &OS,
+                                           SmallVectorImpl<MCFixup> &Fixups,
+                                           const MCSubtargetInfo &STI) const {
+  // For now, we only support RISC-V instructions with 32-bit length
+  uint32_t Bits = getBinaryCodeForInstr(MI, Fixups, STI);
+  support::endian::Writer<support::little>(OS).write(Bits);
+  ++MCNumEmitted; // Keep track of the # of mi's emitted.
+}
+
+unsigned
+RISCVMCCodeEmitter::getMachineOpValue(const MCInst &MI, const MCOperand &MO,
+                                      SmallVectorImpl<MCFixup> &Fixups,
+                                      const MCSubtargetInfo &STI) const {
+
+  if (MO.isReg())
+    return Ctx.getRegisterInfo()->getEncodingValue(MO.getReg());
+
+  if (MO.isImm())
+    return static_cast<unsigned>(MO.getImm());
+
+  llvm_unreachable("Unhandled expression!");
+  return 0;
+}
+
+#include "RISCVGenMCCodeEmitter.inc"
diff --git a/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp b/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp
new file mode 100644
index 00000000000..bad5f440061
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp
@@ -0,0 +1,58 @@
+//===-- RISCVMCTargetDesc.cpp - RISCV Target Descriptions -----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file provides RISCV-specific target descriptions.
+///
+//===----------------------------------------------------------------------===//
+
+#include "RISCVMCTargetDesc.h"
+#include "RISCVMCAsmInfo.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCStreamer.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/TargetRegistry.h"
+
+#define GET_INSTRINFO_MC_DESC
+#include "RISCVGenInstrInfo.inc"
+
+#define GET_REGINFO_MC_DESC
+#include "RISCVGenRegisterInfo.inc"
+
+using namespace llvm;
+
+static MCInstrInfo *createRISCVMCInstrInfo() {
+  MCInstrInfo *X = new MCInstrInfo();
+  InitRISCVMCInstrInfo(X);
+  return X;
+}
+
+static MCRegisterInfo *createRISCVMCRegisterInfo(const Triple &TT) {
+  MCRegisterInfo *X = new MCRegisterInfo();
+  InitRISCVMCRegisterInfo(X, RISCV::X1);
+  return X;
+}
+
+static MCAsmInfo *createRISCVMCAsmInfo(const MCRegisterInfo &MRI,
+                                       const Triple &TT) {
+  return new RISCVMCAsmInfo(TT);
+}
+
+extern "C" void LLVMInitializeRISCVTargetMC() {
+  for (Target *T : {&getTheRISCV32Target(), &getTheRISCV64Target()}) {
+    TargetRegistry::RegisterMCAsmInfo(*T, createRISCVMCAsmInfo);
+    TargetRegistry::RegisterMCInstrInfo(*T, createRISCVMCInstrInfo);
+    TargetRegistry::RegisterMCRegInfo(*T, createRISCVMCRegisterInfo);
+    TargetRegistry::RegisterMCAsmBackend(*T, createRISCVAsmBackend);
+    TargetRegistry::RegisterMCCodeEmitter(*T, createRISCVMCCodeEmitter);
+  }
+}
diff --git a/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h b/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h
new file mode 100644
index 00000000000..be9970eb796
--- /dev/null
+++ b/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h
@@ -0,0 +1,59 @@
+//===-- RISCVMCTargetDesc.h - RISCV Target Descriptions ---------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file provides RISCV specific target descriptions.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVMCTARGETDESC_H
+#define LLVM_LIB_TARGET_RISCV_MCTARGETDESC_RISCVMCTARGETDESC_H
+
+#include "llvm/Config/config.h"
+#include "llvm/MC/MCTargetOptions.h"
+#include "llvm/Support/DataTypes.h"
+#include <memory>
+
+namespace llvm {
+class MCAsmBackend;
+class MCCodeEmitter;
+class MCContext;
+class MCInstrInfo;
+class MCObjectWriter;
+class MCRegisterInfo;
+class MCSubtargetInfo;
+class StringRef;
+class Target;
+class Triple;
+class raw_ostream;
+class raw_pwrite_stream;
+
+Target &getTheRISCV32Target();
+Target &getTheRISCV64Target();
+
+MCCodeEmitter *createRISCVMCCodeEmitter(const MCInstrInfo &MCII,
+                                        const MCRegisterInfo &MRI,
+                                        MCContext &Ctx);
+
+MCAsmBackend *createRISCVAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                    const MCRegisterInfo &MRI,
+                                    const MCTargetOptions &Options);
+
+std::unique_ptr<MCObjectWriter>
+createRISCVELFObjectWriter(raw_pwrite_stream &OS, uint8_t OSABI, bool Is64Bit);
+}
+
+// Defines symbolic names for RISC-V registers.
+#define GET_REGINFO_ENUM
+#include "RISCVGenRegisterInfo.inc"
+
+// Defines symbolic names for RISC-V instructions.
+#define GET_INSTRINFO_ENUM
+#include "RISCVGenInstrInfo.inc"
+
+#endif
diff --git a/lib/Target/RISCV/RISCVTargetMachine.h b/lib/Target/RISCV/RISCVTargetMachine.h
index 6969db2cda3..5c2ec956ee2 100644
--- a/lib/Target/RISCV/RISCVTargetMachine.h
+++ b/lib/Target/RISCV/RISCVTargetMachine.h
@@ -14,6 +14,7 @@
 #ifndef LLVM_LIB_TARGET_RISCV_RISCVTARGETMACHINE_H
 #define LLVM_LIB_TARGET_RISCV_RISCVTARGETMACHINE_H
 
+#include "MCTargetDesc/RISCVMCTargetDesc.h"
 #include "llvm/CodeGen/SelectionDAGTargetInfo.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/Target/TargetMachine.h"
@@ -34,8 +35,6 @@ public:
     return TLOF.get();
   }
 };
-Target &getTheRISCV32Target();
-Target &getTheRISCV64Target();
 }
 
 #endif
diff --git a/lib/Target/RISCV/TargetInfo/RISCVTargetInfo.cpp b/lib/Target/RISCV/TargetInfo/RISCVTargetInfo.cpp
index e1b605c285e..0f369d960fe 100644
--- a/lib/Target/RISCV/TargetInfo/RISCVTargetInfo.cpp
+++ b/lib/Target/RISCV/TargetInfo/RISCVTargetInfo.cpp
@@ -28,8 +28,3 @@ extern "C" void LLVMInitializeRISCVTargetInfo() {
   RegisterTarget<Triple::riscv64> Y(getTheRISCV64Target(), "riscv64",
                                     "64-bit RISC-V", "RISCV");
 }
-
-// FIXME: Temporary stub - this function must be defined for linking
-// to succeed and will be called unconditionally by llc, so must be a no-op.
-// Remove once this function is properly implemented.
-extern "C" void LLVMInitializeRISCVTargetMC() {}
-- 
2.16.2