[ARM] Add plumbing for GlobalISel

Add GlobalISel skeleton, up to the point where we can select a ret void.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286573 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMCallLowering.cpp

@@ -0,0 +1,47 @@
+//===-- llvm/lib/Target/ARM/ARMCallLowering.cpp - Call lowering -----------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file implements the lowering of LLVM calls to machine code calls for
+/// GlobalISel.
+///
+//===----------------------------------------------------------------------===//
+
+#include "ARMCallLowering.h"
+
+#include "ARMBaseInstrInfo.h"
+#include "ARMISelLowering.h"
+
+#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
+
+using namespace llvm;
+
+#ifndef LLVM_BUILD_GLOBAL_ISEL
+#error "This shouldn't be built without GISel"
+#endif
+
+ARMCallLowering::ARMCallLowering(const ARMTargetLowering &TLI)
+    : CallLowering(&TLI) {}
+
+bool ARMCallLowering::lowerReturn(MachineIRBuilder &MIRBuilder,
+                                  const Value *Val, unsigned VReg) const {
+  // We're currently only handling void returns
+  if (Val != nullptr)
+    return false;
+
+  AddDefaultPred(MIRBuilder.buildInstr(ARM::BX_RET));
+
+  return true;
+}
+
+bool ARMCallLowering::lowerFormalArguments(MachineIRBuilder &MIRBuilder,
+                                           const Function &F,
+                                           ArrayRef<unsigned> VRegs) const {
+  return F.arg_empty();
+}

lib/Target/ARM/ARMCallLowering.h

@@ -0,0 +1,37 @@
+//===-- llvm/lib/Target/ARM/ARMCallLowering.h - Call lowering -------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file describes how to lower LLVM calls to machine code calls.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_ARM_ARMCALLLOWERING
+#define LLVM_LIB_TARGET_ARM_ARMCALLLOWERING
+
+#include "llvm/CodeGen/CallingConvLower.h"
+#include "llvm/CodeGen/GlobalISel/CallLowering.h"
+#include "llvm/CodeGen/ValueTypes.h"
+
+namespace llvm {
+
+class ARMTargetLowering;
+
+class ARMCallLowering : public CallLowering {
+public:
+  ARMCallLowering(const ARMTargetLowering &TLI);
+
+  bool lowerReturn(MachineIRBuilder &MIRBuiler, const Value *Val,
+                   unsigned VReg) const override;
+
+  bool lowerFormalArguments(MachineIRBuilder &MIRBuilder, const Function &F,
+                            ArrayRef<unsigned> VRegs) const override;
+};
+} // End of namespace llvm
+#endif

lib/Target/ARM/ARMInstructionSelector.cpp

@@ -0,0 +1,36 @@
+//===- ARMInstructionSelector.cpp ----------------------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the targeting of the InstructionSelector class for ARM.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#include "ARMInstructionSelector.h"
+#include "ARMRegisterBankInfo.h"
+#include "ARMSubtarget.h"
+#include "ARMTargetMachine.h"
+#include "llvm/Support/Debug.h"
+
+#define DEBUG_TYPE "arm-isel"
+
+using namespace llvm;
+
+#ifndef LLVM_BUILD_GLOBAL_ISEL
+#error "You shouldn't build this"
+#endif
+
+ARMInstructionSelector::ARMInstructionSelector(const ARMBaseTargetMachine &TM,
+                                               const ARMSubtarget &STI,
+                                               const ARMRegisterBankInfo &RBI)
+    : InstructionSelector(), TM(TM), STI(STI), TII(*STI.getInstrInfo()),
+      TRI(*STI.getRegisterInfo()), RBI(RBI) {}
+
+bool ARMInstructionSelector::select(llvm::MachineInstr &I) const {
+  return !isPreISelGenericOpcode(I.getOpcode());
+}

lib/Target/ARM/ARMInstructionSelector.h

@@ -0,0 +1,42 @@
+//===- ARMInstructionSelector ------------------------------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file declares the targeting of the InstructionSelector class for ARM.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_ARM_ARMINSTRUCTIONSELECTOR_H
+#define LLVM_LIB_TARGET_ARM_ARMINSTRUCTIONSELECTOR_H
+
+#include "llvm/CodeGen/GlobalISel/InstructionSelector.h"
+
+namespace llvm {
+class ARMBaseInstrInfo;
+class ARMBaseRegisterInfo;
+class ARMBaseTargetMachine;
+class ARMRegisterBankInfo;
+class ARMSubtarget;
+
+class ARMInstructionSelector : public InstructionSelector {
+public:
+  ARMInstructionSelector(const ARMBaseTargetMachine &TM,
+                         const ARMSubtarget &STI,
+                         const ARMRegisterBankInfo &RBI);
+
+  virtual bool select(MachineInstr &I) const override;
+
+private:
+  const ARMBaseTargetMachine &TM;
+  const ARMSubtarget &STI;
+  const ARMBaseInstrInfo &TII;
+  const ARMBaseRegisterInfo &TRI;
+  const ARMRegisterBankInfo &RBI;
+};
+
+} // End llvm namespace.
+#endif

lib/Target/ARM/ARMLegalizerInfo.cpp

@@ -0,0 +1,28 @@
+//===- ARMLegalizerInfo.cpp --------------------------------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the targeting of the Machinelegalizer class for ARM.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#include "ARMLegalizerInfo.h"
+#include "llvm/CodeGen/ValueTypes.h"
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Target/TargetOpcodes.h"
+
+using namespace llvm;
+
+#ifndef LLVM_BUILD_GLOBAL_ISEL
+#error "You shouldn't build this"
+#endif
+
+ARMLegalizerInfo::ARMLegalizerInfo() {
+  computeTables();
+}

lib/Target/ARM/ARMLegalizerInfo.h

@@ -0,0 +1,29 @@
+//===- ARMLegalizerInfo ------------------------------------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file declares the targeting of the Machinelegalizer class for ARM.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_ARM_ARMMACHINELEGALIZER_H
+#define LLVM_LIB_TARGET_ARM_ARMMACHINELEGALIZER_H
+
+#include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
+
+namespace llvm {
+
+class LLVMContext;
+
+/// This class provides the information for the target register banks.
+class ARMLegalizerInfo : public LegalizerInfo {
+public:
+  ARMLegalizerInfo();
+};
+} // End llvm namespace.
+#endif

lib/Target/ARM/ARMRegisterBankInfo.cpp

@@ -0,0 +1,27 @@
+//===- ARMRegisterBankInfo.cpp -----------------------------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the targeting of the RegisterBankInfo class for ARM.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#include "ARMRegisterBankInfo.h"
+#include "llvm/CodeGen/GlobalISel/RegisterBank.h"
+#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/Target/TargetRegisterInfo.h"
+
+using namespace llvm;
+
+#ifndef LLVM_BUILD_GLOBAL_ISEL
+#error "You shouldn't build this"
+#endif
+
+ARMRegisterBankInfo::ARMRegisterBankInfo(const TargetRegisterInfo &TRI)
+    : RegisterBankInfo(nullptr, 0) {}

lib/Target/ARM/ARMRegisterBankInfo.h

@@ -0,0 +1,29 @@
+//===- ARMRegisterBankInfo ---------------------------------------*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file declares the targeting of the RegisterBankInfo class for ARM.
+/// \todo This should be generated by TableGen.
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_LIB_TARGET_ARM_ARMREGISTERBANKINFO_H
+#define LLVM_LIB_TARGET_ARM_ARMREGISTERBANKINFO_H
+
+#include "llvm/CodeGen/GlobalISel/RegisterBankInfo.h"
+
+namespace llvm {
+
+class TargetRegisterInfo;
+
+/// This class provides the information for the target register banks.
+class ARMRegisterBankInfo final : public RegisterBankInfo {
+public:
+  ARMRegisterBankInfo(const TargetRegisterInfo &TRI);
+};
+} // End llvm namespace.
+#endif

lib/Target/ARM/ARMSubtarget.cpp

@@ -98,7 +98,27 @@ ARMSubtarget::ARMSubtarget(const Triple &TT, const std::string &CPU,
                     : !isThumb()
                           ? (ARMBaseInstrInfo *)new ARMInstrInfo(*this)
                           : (ARMBaseInstrInfo *)new Thumb2InstrInfo(*this)),
-      TLInfo(TM, *this) {}
+      TLInfo(TM, *this), GISel() {}
+
+const CallLowering *ARMSubtarget::getCallLowering() const {
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getCallLowering();
+}
+
+const InstructionSelector *ARMSubtarget::getInstructionSelector() const {
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getInstructionSelector();
+}
+
+const LegalizerInfo *ARMSubtarget::getLegalizerInfo() const {
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getLegalizerInfo();
+}
+
+const RegisterBankInfo *ARMSubtarget::getRegBankInfo() const {
+  assert(GISel && "Access to GlobalISel APIs not set");
+  return GISel->getRegBankInfo();
+}
 
 bool ARMSubtarget::isXRaySupported() const {
   // We don't currently suppport Thumb, but Windows requires Thumb.

lib/Target/ARM/ARMSubtarget.h

@@ -25,6 +25,7 @@
 #include "Thumb1InstrInfo.h"
 #include "Thumb2InstrInfo.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/CodeGen/GlobalISel/GISelAccessor.h"
 #include "llvm/IR/DataLayout.h"
 #include "llvm/MC/MCInstrItineraries.h"
 #include "llvm/Target/TargetSubtargetInfo.h"
@@ -350,6 +351,9 @@ public:
   ARMSubtarget(const Triple &TT, const std::string &CPU, const std::string &FS,
                const ARMBaseTargetMachine &TM, bool IsLittle);
 
+  /// This object will take onwership of \p GISelAccessor.
+  void setGISelAccessor(GISelAccessor &GISel) { this->GISel.reset(&GISel); }
+
   /// getMaxInlineSizeThreshold - Returns the maximum memset / memcpy size
   /// that still makes it profitable to inline the call.
   unsigned getMaxInlineSizeThreshold() const {
@@ -379,6 +383,11 @@ public:
     return &InstrInfo->getRegisterInfo();
   }
 
+  const CallLowering *getCallLowering() const override;
+  const InstructionSelector *getInstructionSelector() const override;
+  const LegalizerInfo *getLegalizerInfo() const override;
+  const RegisterBankInfo *getRegBankInfo() const override;
+
 private:
   ARMSelectionDAGInfo TSInfo;
   // Either Thumb1FrameLowering or ARMFrameLowering.
@@ -387,6 +396,11 @@ private:
   std::unique_ptr<ARMBaseInstrInfo> InstrInfo;
   ARMTargetLowering   TLInfo;
 
+  /// Gather the accessor points to GlobalISel-related APIs.
+  /// This is used to avoid ifndefs spreading around while GISel is
+  /// an optional library.
+  std::unique_ptr<GISelAccessor> GISel;
+
   void initializeEnvironment();
   void initSubtargetFeatures(StringRef CPU, StringRef FS);
   ARMFrameLowering *initializeFrameLowering(StringRef CPU, StringRef FS);

lib/Target/ARM/ARMTargetMachine.cpp

@@ -10,11 +10,19 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "ARM.h"
-#include "ARMFrameLowering.h"
 #include "ARMTargetMachine.h"
+#include "ARM.h"
+#include "ARMCallLowering.h"
+#include "ARMFrameLowering.h"
+#include "ARMInstructionSelector.h"
+#include "ARMLegalizerInfo.h"
+#include "ARMRegisterBankInfo.h"
 #include "ARMTargetObjectFile.h"
 #include "ARMTargetTransformInfo.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/TargetPassConfig.h"
 #include "llvm/IR/Function.h"
@@ -22,8 +30,8 @@
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/FormattedStream.h"
-#include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetParser.h"
+#include "llvm/Support/TargetRegistry.h"
 #include "llvm/Target/TargetOptions.h"
 #include "llvm/Transforms/Scalar.h"
 using namespace llvm;
@@ -57,6 +65,7 @@ extern "C" void LLVMInitializeARMTarget() {
   RegisterTargetMachine<ThumbBETargetMachine> B(getTheThumbBETarget());
 
   PassRegistry &Registry = *PassRegistry::getPassRegistry();
+  initializeGlobalISel(Registry);
   initializeARMLoadStoreOptPass(Registry);
   initializeARMPreAllocLoadStoreOptPass(Registry);
 }
@@ -231,6 +240,29 @@ ARMBaseTargetMachine::ARMBaseTargetMachine(const Target &T, const Triple &TT,
 
 ARMBaseTargetMachine::~ARMBaseTargetMachine() {}
 
+#ifdef LLVM_BUILD_GLOBAL_ISEL
+namespace {
+struct ARMGISelActualAccessor : public GISelAccessor {
+  std::unique_ptr<CallLowering> CallLoweringInfo;
+  std::unique_ptr<InstructionSelector> InstSelector;
+  std::unique_ptr<LegalizerInfo> Legalizer;
+  std::unique_ptr<RegisterBankInfo> RegBankInfo;
+  const CallLowering *getCallLowering() const override {
+    return CallLoweringInfo.get();
+  }
+  const InstructionSelector *getInstructionSelector() const override {
+    return InstSelector.get();
+  }
+  const class LegalizerInfo *getLegalizerInfo() const override {
+    return Legalizer.get();
+  }
+  const RegisterBankInfo *getRegBankInfo() const override {
+    return RegBankInfo.get();
+  }
+};
+} // End anonymous namespace.
+#endif
+
 const ARMSubtarget *
 ARMBaseTargetMachine::getSubtargetImpl(const Function &F) const {
   Attribute CPUAttr = F.getFnAttribute("target-cpu");
@@ -263,6 +295,24 @@ ARMBaseTargetMachine::getSubtargetImpl(const Function &F) const {
     resetTargetOptions(F);
     I = llvm::make_unique<ARMSubtarget>(TargetTriple, CPU, FS, *this, isLittle);
   }
+
+#ifndef LLVM_BUILD_GLOBAL_ISEL
+  GISelAccessor *GISel = new GISelAccessor();
+#else
+  ARMGISelActualAccessor *GISel = new ARMGISelActualAccessor();
+  GISel->CallLoweringInfo.reset(new ARMCallLowering(*I->getTargetLowering()));
+  GISel->Legalizer.reset(new ARMLegalizerInfo());
+
+  auto *RBI = new ARMRegisterBankInfo(*I->getRegisterInfo());
+
+  // FIXME: At this point, we can't rely on Subtarget having RBI.
+  // It's awkward to mix passing RBI and the Subtarget; should we pass
+  // TII/TRI as well?
+  GISel->InstSelector.reset(new ARMInstructionSelector(*this, *I, *RBI));
+
+  GISel->RegBankInfo.reset(RBI);
+#endif
+  I->setGISelAccessor(*GISel);
   return I.get();
 }
 
@@ -353,6 +403,12 @@ public:
   void addIRPasses() override;
   bool addPreISel() override;
   bool addInstSelector() override;
+#ifdef LLVM_BUILD_GLOBAL_ISEL
+  bool addIRTranslator() override;
+  bool addLegalizeMachineIR() override;
+  bool addRegBankSelect() override;
+  bool addGlobalInstructionSelect() override;
+#endif
   void addPreRegAlloc() override;
   void addPreSched2() override;
   void addPreEmitPass() override;
@@ -413,6 +469,28 @@ bool ARMPassConfig::addInstSelector() {
   return false;
 }
 
+#ifdef LLVM_BUILD_GLOBAL_ISEL
+bool ARMPassConfig::addIRTranslator() {
+  addPass(new IRTranslator());
+  return false;
+}
+
+bool ARMPassConfig::addLegalizeMachineIR() {
+  addPass(new Legalizer());
+  return false;
+}
+
+bool ARMPassConfig::addRegBankSelect() {
+  addPass(new RegBankSelect());
+  return false;
+}
+
+bool ARMPassConfig::addGlobalInstructionSelect() {
+  addPass(new InstructionSelect());
+  return false;
+}
+#endif
+
 void ARMPassConfig::addPreRegAlloc() {
   if (getOptLevel() != CodeGenOpt::None) {
     addPass(createMLxExpansionPass());

lib/Target/ARM/CMakeLists.txt

@@ -13,6 +13,21 @@ tablegen(LLVM ARMGenSubtargetInfo.inc -gen-subtarget)
 tablegen(LLVM ARMGenDisassemblerTables.inc -gen-disassembler)
 add_public_tablegen_target(ARMCommonTableGen)
 
+# Add GlobalISel files if the user wants to build it.
+set(GLOBAL_ISEL_FILES
+  ARMCallLowering.cpp
+  ARMInstructionSelector.cpp
+  ARMLegalizerInfo.cpp
+  ARMRegisterBankInfo.cpp
+  )
+
+if(LLVM_BUILD_GLOBAL_ISEL)
+  set(GLOBAL_ISEL_BUILD_FILES ${GLOBAL_ISEL_FILES})
+else()
+  set(GLOBAL_ISEL_BUILD_FILES "")
+  set(LLVM_OPTIONAL_SOURCES LLVMGlobalISel ${GLOBAL_ISEL_FILES})
+endif()
+
 add_llvm_target(ARMCodeGen
   A15SDOptimizer.cpp
   ARMAsmPrinter.cpp
@@ -45,6 +60,7 @@ add_llvm_target(ARMCodeGen
   Thumb2InstrInfo.cpp
   Thumb2SizeReduction.cpp
   ARMComputeBlockSize.cpp
+  ${GLOBAL_ISEL_BUILD_FILES}
   )
 
 add_subdirectory(TargetInfo)

lib/Target/ARM/LLVMBuild.txt

@@ -31,5 +31,5 @@ has_jit = 1
 type = Library
 name = ARMCodeGen
 parent = ARM
-required_libraries = ARMAsmPrinter ARMDesc ARMInfo Analysis AsmPrinter CodeGen Core MC Scalar SelectionDAG Support Target
+required_libraries = ARMAsmPrinter ARMDesc ARMInfo Analysis AsmPrinter CodeGen Core MC Scalar SelectionDAG Support Target GlobalISel
 add_to_library_groups = ARM

test/CodeGen/ARM/GlobalISel/arm-irtranslator.ll

@@ -0,0 +1,9 @@
+; RUN: llc -mtriple arm-unknown -global-isel -stop-after=irtranslator %s -o - | FileCheck %s
+
+define void @test_void_return() {
+; CHECK-LABEL: name: test_void_return
+; CHECK: BX_RET 14, _
+entry:
+  ret void
+}
+

test/CodeGen/ARM/GlobalISel/lit.local.cfg

@@ -0,0 +1,2 @@
+if not 'global-isel' in config.root.available_features:
+    config.unsupported = True