Add stub DirectX backend

[beanz]

Summary

This is the bare minimum needed to get the DirectX target compiling,
but does not actually do anything.

[pete]

LGTM

[arsenm]

llvm/lib/Target/DirectX/DirectXTargetMachine.cpp

43

Dead return

50

Dead return

llvm/lib/Target/DirectX/CMakeLists.txt

+add_llvm_component_group(DirectX)
+
+set(LLVM_TARGET_DEFINITIONS DirectX.td)
+
+tablegen(LLVM DirectXGenSubtargetInfo.inc -gen-subtarget)
+
+add_public_tablegen_target(DirectXCommonTableGen)
+
+add_llvm_target(DirectXCodeGen
+  DirectXSubtarget.cpp
+  DirectXTargetMachine.cpp
+
+  LINK_COMPONENTS
+  Bitwriter
+  Core
+  Support
+  DirectXInfo
+
+  ADD_TO_COMPONENT
+  DirectX
+)
+
+add_subdirectory(MCTargetDesc)
+add_subdirectory(TargetInfo)

llvm/lib/Target/DirectX/DirectX.td

+//- DirectX.td - Describe the DirectX Target Machine ----------*- 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This is a target description file for the DirectX target
+///
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+// Target-independent interfaces which we are implementing
+//===----------------------------------------------------------------------===//
+
+include "llvm/Target/Target.td"
+
+//===----------------------------------------------------------------------===//
+// DirectX Subtarget features.
+//===----------------------------------------------------------------------===//
+
+def DirectXInstrInfo : InstrInfo;
+
+//===----------------------------------------------------------------------===//
+// DirectX Processors supported.
+//===----------------------------------------------------------------------===//
+
+def : ProcessorModel<"generic", NoSchedModel, []>;
+
+
+//===----------------------------------------------------------------------===//
+// Target Declaration
+//===----------------------------------------------------------------------===//
+
+def DirectXAsmParser : AsmParser {
+  // The physical register names are not in the binary format or asm text
+  let ShouldEmitMatchRegisterName = 0;
+}
+
+def DirectXAsmWriter : AsmWriter {
+  string AsmWriterClassName  = "InstPrinter";
+  int PassSubtarget = 0;
+  int Variant = 0;
+  bit isMCAsmWriter = 1;
+}
+
+def DirectX : Target {
+  let InstructionSet = DirectXInstrInfo;
+  let AssemblyParsers  = [DirectXAsmParser];
+  let AssemblyWriters = [DirectXAsmWriter];
+}

llvm/lib/Target/DirectX/DirectXSubtarget.h

+//===-- DirectXSubtarget.h - Define Subtarget for DirectX -------*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the DirectX specific subclass of TargetSubtargetInfo.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DIRECTX_DIRECTXSUBTARGET_H
+#define LLVM_DIRECTX_DIRECTXSUBTARGET_H
+
+#include "DirectXTargetLowering.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/Target/TargetMachine.h"
+
+#define GET_SUBTARGETINFO_HEADER
+#include "DirectXGenSubtargetInfo.inc"
+
+namespace llvm {
+
+class DirectXTargetMachine;
+
+class DirectXSubtarget : public DirectXGenSubtargetInfo {
+  DirectXTargetLowering TL;
+
+public:
+  DirectXSubtarget(const Triple &TT, StringRef CPU, StringRef FS,
+                   const DirectXTargetMachine &TM);
+
+  /// Parses a subtarget feature string, setting appropriate options.
+  /// \note Definition of function is auto generated by `tblgen`.
+  void ParseSubtargetFeatures(StringRef CPU, StringRef TuneCPU, StringRef FS);
+
+  const DirectXTargetLowering *getTargetLowering() const override {
+    return &TL;
+  }
+};
+
+} // end namespace llvm
+
+#endif // LLVM_DIRECTX_DIRECTXSUBTARGET_H

llvm/lib/Target/DirectX/DirectXSubtarget.cpp

+//===-- DirectXSubtarget.cpp - DirectX 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
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file implements the DirectX-specific subclass of TargetSubtarget.
+///
+//===----------------------------------------------------------------------===//
+
+#include "DirectXSubtarget.h"
+#include "DirectXTargetLowering.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "directx-subtarget"
+
+#define GET_SUBTARGETINFO_CTOR
+#define GET_SUBTARGETINFO_TARGET_DESC
+#include "DirectXGenSubtargetInfo.inc"
+
+DirectXSubtarget::DirectXSubtarget(const Triple &TT, StringRef CPU,
+                                   StringRef FS, const DirectXTargetMachine &TM)
+    : DirectXGenSubtargetInfo(TT, CPU, CPU, FS), TL(TM, *this) {}

llvm/lib/Target/DirectX/DirectXTargetLowering.h

+//===-- DirectXTargetLowering.h - Define DX TargetLowering  -----*- 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the DirectX specific subclass of TargetLowering.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DIRECTX_DIRECTXTARGETLOWERING_H
+#define LLVM_DIRECTX_DIRECTXTARGETLOWERING_H
+
+#include "llvm/CodeGen/TargetLowering.h"
+
+namespace llvm {
+
+class DirectXSubtarget;
+class DirectXTargetMachine;
+
+class DirectXTargetLowering : public TargetLowering {
+public:
+  explicit DirectXTargetLowering(const DirectXTargetMachine &TM,
+                                 const DirectXSubtarget &STI);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_DIRECTX_DIRECTXTARGETLOWERING_H

llvm/lib/Target/DirectX/DirectXTargetMachine.h

+//===- DirectXTargetMachine.h - DirectX Target Implementation ---*- 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
+//
+//===----------------------------------------------------------------------===//
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DIRECTX_DIRECTXTARGETMACHINE_H
+#define LLVM_DIRECTX_DIRECTXTARGETMACHINE_H
+
+#include "DirectXSubtarget.h"
+#include "llvm/Target/TargetMachine.h"
+
+namespace llvm {
+class Function;
+class DirectXTargetMachine : public LLVMTargetMachine {
+  std::unique_ptr<TargetLoweringObjectFile> TLOF;
+  std::unique_ptr<DirectXSubtarget> Subtarget;
+
+public:
+  DirectXTargetMachine(const Target &T, const Triple &TT, StringRef CPU,
+                       StringRef FS, const TargetOptions &Options,
+                       Optional<Reloc::Model> RM, Optional<CodeModel::Model> CM,
+                       CodeGenOpt::Level OL, bool JIT);
+
+  ~DirectXTargetMachine() override;
+
+  bool addPassesToEmitFile(PassManagerBase &PM, raw_pwrite_stream &Out,
+                           raw_pwrite_stream *DwoOut, CodeGenFileType FileType,
+                           bool DisableVerify,
+                           MachineModuleInfoWrapperPass *MMIWP) override;
+
+  bool addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
+                         raw_pwrite_stream &Out, bool DisableVerify) override;
+
+  const DirectXSubtarget *getSubtargetImpl(const Function &) const override;
+
+  TargetPassConfig *createPassConfig(PassManagerBase &PM) override;
+
+  TargetLoweringObjectFile *getObjFileLowering() const override {
+    return TLOF.get();
+  }
+
+  TargetTransformInfo getTargetTransformInfo(const Function &F) const override;
+};
+} // namespace llvm
+
+#endif // LLVM_DIRECTX_DIRECTXTARGETMACHINE_H

llvm/lib/Target/DirectX/DirectXTargetMachine.cpp

+//===- DirectXTargetMachine.cpp - DirectX Target Implementation -*- 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 contains DirectX target initializer.
+///
+//===----------------------------------------------------------------------===//
+
+#include "DirectXTargetMachine.h"
+#include "DirectXSubtarget.h"
+#include "DirectXTargetTransformInfo.h"
+#include "TargetInfo/DirectXTargetInfo.h"
+#include "llvm/Bitcode/BitcodeWriterPass.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/IR/IRPrintingPasses.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/MC/SectionKind.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/CodeGen.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Target/TargetLoweringObjectFile.h"
+
+using namespace llvm;
+
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTarget() {
+  RegisterTargetMachine<DirectXTargetMachine> X(getTheDirectXTarget());
+}
+
+class DXILTargetObjectFile : public TargetLoweringObjectFile {
+public:
+  DXILTargetObjectFile() = default;
+
+  MCSection *getExplicitSectionGlobal(const GlobalObject *GO, SectionKind Kind,
+                                      const TargetMachine &TM) const override {
+    llvm_unreachable("Not supported!");
+    return nullptr;
+  }
+
+protected:
+  MCSection *SelectSectionForGlobal(const GlobalObject *GO, SectionKind Kind,
+                                    const TargetMachine &TM) const override {
+    llvm_unreachable("Not supported!");
+    return nullptr;
+  }
+};
+
+class DirectXPassConfig : public TargetPassConfig {
+public:
+  DirectXPassConfig(DirectXTargetMachine &TM, PassManagerBase &PM)
+      : TargetPassConfig(TM, PM) {}
+
+  DirectXTargetMachine &getDirectXTargetMachine() const {
+    return getTM<DirectXTargetMachine>();
+  }
+
+  FunctionPass *createTargetRegisterAllocator(bool) override { return nullptr; }
+};
+
+DirectXTargetMachine::DirectXTargetMachine(const Target &T, const Triple &TT,
+                                           StringRef CPU, StringRef FS,
+                                           const TargetOptions &Options,
+                                           Optional<Reloc::Model> RM,
+                                           Optional<CodeModel::Model> CM,
+                                           CodeGenOpt::Level OL, bool JIT)
+    : LLVMTargetMachine(T,
+                        "e-m:e-p:32:32-i1:32-i8:8-i16:16-i32:32-i64:64-f16:16-"
+                        "f32:32-f64:64-n8:16:32:64",
+                        TT, CPU, FS, Options, Reloc::Static, CodeModel::Small,
+                        OL),
+      TLOF(std::make_unique<DXILTargetObjectFile>()),
+      Subtarget(std::make_unique<DirectXSubtarget>(TT, CPU, FS, *this)) {}
+
+DirectXTargetMachine::~DirectXTargetMachine() {}
+
+bool DirectXTargetMachine::addPassesToEmitFile(
+    PassManagerBase &PM, raw_pwrite_stream &Out, raw_pwrite_stream *DwoOut,
+    CodeGenFileType FileType, bool DisableVerify,
+    MachineModuleInfoWrapperPass *MMIWP) {
+  switch (FileType) {
+  case CGFT_AssemblyFile:
+    PM.add(createPrintModulePass(Out, "", true));
+    break;
+  case CGFT_ObjectFile:
+    // TODO: Write DXIL instead of bitcode
+    PM.add(createBitcodeWriterPass(Out, true, false, false));
+    break;
+  case CGFT_Null:
+    break;
+  }
+  return false;
+}
+
+bool DirectXTargetMachine::addPassesToEmitMC(PassManagerBase &PM,
+                                             MCContext *&Ctx,
+                                             raw_pwrite_stream &Out,
+                                             bool DisableVerify) {
+  return true;
+}
+
+TargetPassConfig *DirectXTargetMachine::createPassConfig(PassManagerBase &PM) {
+  return new DirectXPassConfig(*this, PM);
+}
+
+const DirectXSubtarget *
+DirectXTargetMachine::getSubtargetImpl(const Function &) const {
+  return Subtarget.get();
+}
+
+TargetTransformInfo
+DirectXTargetMachine::getTargetTransformInfo(const Function &F) const {
+  return TargetTransformInfo(DirectXTTIImpl(this, F));
+}
+
+DirectXTargetLowering::DirectXTargetLowering(const DirectXTargetMachine &TM,
+                                             const DirectXSubtarget &STI)
+    : TargetLowering(TM) {}

llvm/lib/Target/DirectX/DirectXTargetTransformInfo.h

+//===- DirectXTargetTransformInfo.h - DirectX TTI ---------------*- 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
+//
+//===----------------------------------------------------------------------===//
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DIRECTX_DIRECTXTARGETTRANSFORMINFO_H
+#define LLVM_DIRECTX_DIRECTXTARGETTRANSFORMINFO_H
+
+#include "DirectXSubtarget.h"
+#include "DirectXTargetMachine.h"
+#include "llvm/CodeGen/BasicTTIImpl.h"
+#include "llvm/IR/Function.h"
+
+namespace llvm {
+class DirectXTTIImpl : public BasicTTIImplBase<DirectXTTIImpl> {
+  using BaseT = BasicTTIImplBase<DirectXTTIImpl>;
+  using TTI = TargetTransformInfo;
+
+  friend BaseT;
+
+  const DirectXSubtarget *ST;
+  const DirectXTargetLowering *TLI;
+
+  const DirectXSubtarget *getST() const { return ST; }
+  const DirectXTargetLowering *getTLI() const { return TLI; }
+
+public:
+  explicit DirectXTTIImpl(const DirectXTargetMachine *TM, const Function &F)
+      : BaseT(TM, F.getParent()->getDataLayout()), ST(TM->getSubtargetImpl(F)),
+        TLI(ST->getTargetLowering()) {}
+};
+} // namespace llvm
+
+#endif // LLVM_DIRECTX_DIRECTXTARGETTRANSFORMINFO_H

llvm/lib/Target/DirectX/MCTargetDesc/CMakeLists.txt

+add_llvm_component_library(LLVMDirectXDesc
+  DirectXMCTargetDesc.cpp
+
+  LINK_COMPONENTS
+  DirectXInfo
+  Support
+
+  ADD_TO_COMPONENT
+  DirectX
+  )

llvm/lib/Target/DirectX/MCTargetDesc/DirectXMCTargetDesc.cpp

+//===- DirectXMCTargetDesc.cpp - DirectX Target Implementation --*- 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 contains DirectX target initializer.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Triple.h"
+#include "llvm/MC/MCAsmBackend.h"
+#include "llvm/MC/MCCodeEmitter.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCSchedule.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Support/Compiler.h"
+
+using namespace llvm;
+
+#define GET_SUBTARGETINFO_MC_DESC
+#include "DirectXGenSubtargetInfo.inc"
+
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTargetMC() {}

llvm/lib/Target/DirectX/TargetInfo/CMakeLists.txt

+add_llvm_component_library(LLVMDirectXInfo
+  DirectXTargetInfo.cpp
+
+  LINK_COMPONENTS
+  MC
+  Support
+
+  ADD_TO_COMPONENT
+  DirectX
+)
+
+add_dependencies(LLVMDirectXInfo DirectXCommonTableGen)

llvm/lib/Target/DirectX/TargetInfo/DirectXTargetInfo.h

+//===-- DirectXTargetInfo.h - DircetX Target Implementation -----*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DIRECTX_TARGETINFO_DIRECTXTARGETINFO_H
+#define LLVM_DIRECTX_TARGETINFO_DIRECTXTARGETINFO_H
+
+namespace llvm {
+class Target;
+
+Target &getTheDirectXTarget();
+} // namespace llvm
+
+#endif // LLVM_DIRECTX_TARGETINFO_DIRECTXTARGETINFO_H

llvm/lib/Target/DirectX/TargetInfo/DirectXTargetInfo.cpp

+//===- DirectXTargetInfo.cpp - DirectX Target Implementation ----*- 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 contains DirectX target initializer.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Triple.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/Compiler.h"
+
+namespace llvm {
+Target &getTheDirectXTarget() {
+  static Target TheDirectXTarget;
+  return TheDirectXTarget;
+}
+} // namespace llvm
+
+using namespace llvm;
+
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTargetInfo() {
+  RegisterTarget<Triple::dxil, /*HasJIT=*/false> X(
+      getTheDirectXTarget(), "dxil", "DirectX Intermediate Language", "DXIL");
+}