295 lines
12 KiB
C++
295 lines
12 KiB
C++
//===-- Assembler.cpp -------------------------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "Assembler.h"
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#include "Target.h"
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#include "llvm/CodeGen/GlobalISel/CallLowering.h"
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#include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineModuleInfo.h"
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#include "llvm/CodeGen/MachineRegisterInfo.h"
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#include "llvm/CodeGen/TargetInstrInfo.h"
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#include "llvm/CodeGen/TargetPassConfig.h"
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#include "llvm/CodeGen/TargetSubtargetInfo.h"
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#include "llvm/ExecutionEngine/SectionMemoryManager.h"
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#include "llvm/IR/LegacyPassManager.h"
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#include "llvm/MC/MCInstrInfo.h"
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#include "llvm/Support/MemoryBuffer.h"
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namespace exegesis {
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static constexpr const char ModuleID[] = "ExegesisInfoTest";
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static constexpr const char FunctionID[] = "foo";
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static std::vector<llvm::MCInst>
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generateSnippetSetupCode(const ExegesisTarget &ET,
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const llvm::MCSubtargetInfo *const MSI,
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llvm::ArrayRef<RegisterValue> RegisterInitialValues,
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bool &IsSnippetSetupComplete) {
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std::vector<llvm::MCInst> Result;
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for (const RegisterValue &RV : RegisterInitialValues) {
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// Load a constant in the register.
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const auto SetRegisterCode = ET.setRegTo(*MSI, RV.Register, RV.Value);
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if (SetRegisterCode.empty())
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IsSnippetSetupComplete = false;
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Result.insert(Result.end(), SetRegisterCode.begin(), SetRegisterCode.end());
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}
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return Result;
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}
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// Small utility function to add named passes.
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static bool addPass(llvm::PassManagerBase &PM, llvm::StringRef PassName,
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llvm::TargetPassConfig &TPC) {
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const llvm::PassRegistry *PR = llvm::PassRegistry::getPassRegistry();
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const llvm::PassInfo *PI = PR->getPassInfo(PassName);
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if (!PI) {
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llvm::errs() << " run-pass " << PassName << " is not registered.\n";
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return true;
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}
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if (!PI->getNormalCtor()) {
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llvm::errs() << " cannot create pass: " << PI->getPassName() << "\n";
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return true;
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}
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llvm::Pass *P = PI->getNormalCtor()();
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std::string Banner = std::string("After ") + std::string(P->getPassName());
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PM.add(P);
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TPC.printAndVerify(Banner);
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return false;
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}
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// Creates a void(int8*) MachineFunction.
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static llvm::MachineFunction &
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createVoidVoidPtrMachineFunction(llvm::StringRef FunctionID,
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llvm::Module *Module,
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llvm::MachineModuleInfo *MMI) {
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llvm::Type *const ReturnType = llvm::Type::getInt32Ty(Module->getContext());
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llvm::Type *const MemParamType = llvm::PointerType::get(
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llvm::Type::getInt8Ty(Module->getContext()), 0 /*default address space*/);
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llvm::FunctionType *FunctionType =
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llvm::FunctionType::get(ReturnType, {MemParamType}, false);
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llvm::Function *const F = llvm::Function::Create(
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FunctionType, llvm::GlobalValue::InternalLinkage, FunctionID, Module);
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// Making sure we can create a MachineFunction out of this Function even if it
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// contains no IR.
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F->setIsMaterializable(true);
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return MMI->getOrCreateMachineFunction(*F);
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}
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static void fillMachineFunction(llvm::MachineFunction &MF,
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llvm::ArrayRef<unsigned> LiveIns,
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llvm::ArrayRef<llvm::MCInst> Instructions) {
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llvm::MachineBasicBlock *MBB = MF.CreateMachineBasicBlock();
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MF.push_back(MBB);
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for (const unsigned Reg : LiveIns)
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MBB->addLiveIn(Reg);
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const llvm::MCInstrInfo *MCII = MF.getTarget().getMCInstrInfo();
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llvm::DebugLoc DL;
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for (const llvm::MCInst &Inst : Instructions) {
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const unsigned Opcode = Inst.getOpcode();
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const llvm::MCInstrDesc &MCID = MCII->get(Opcode);
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llvm::MachineInstrBuilder Builder = llvm::BuildMI(MBB, DL, MCID);
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for (unsigned OpIndex = 0, E = Inst.getNumOperands(); OpIndex < E;
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++OpIndex) {
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const llvm::MCOperand &Op = Inst.getOperand(OpIndex);
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if (Op.isReg()) {
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const bool IsDef = OpIndex < MCID.getNumDefs();
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unsigned Flags = 0;
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const llvm::MCOperandInfo &OpInfo = MCID.operands().begin()[OpIndex];
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if (IsDef && !OpInfo.isOptionalDef())
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Flags |= llvm::RegState::Define;
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Builder.addReg(Op.getReg(), Flags);
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} else if (Op.isImm()) {
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Builder.addImm(Op.getImm());
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} else {
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llvm_unreachable("Not yet implemented");
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}
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}
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}
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// Insert the return code.
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const llvm::TargetInstrInfo *TII = MF.getSubtarget().getInstrInfo();
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if (TII->getReturnOpcode() < TII->getNumOpcodes()) {
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llvm::BuildMI(MBB, DL, TII->get(TII->getReturnOpcode()));
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} else {
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llvm::MachineIRBuilder MIB(MF);
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MIB.setMBB(*MBB);
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MF.getSubtarget().getCallLowering()->lowerReturn(MIB, nullptr, 0);
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}
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}
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static std::unique_ptr<llvm::Module>
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createModule(const std::unique_ptr<llvm::LLVMContext> &Context,
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const llvm::DataLayout DL) {
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auto Module = llvm::make_unique<llvm::Module>(ModuleID, *Context);
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Module->setDataLayout(DL);
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return Module;
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}
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llvm::BitVector getFunctionReservedRegs(const llvm::TargetMachine &TM) {
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std::unique_ptr<llvm::LLVMContext> Context =
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llvm::make_unique<llvm::LLVMContext>();
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std::unique_ptr<llvm::Module> Module =
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createModule(Context, TM.createDataLayout());
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std::unique_ptr<llvm::MachineModuleInfo> MMI =
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llvm::make_unique<llvm::MachineModuleInfo>(&TM);
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llvm::MachineFunction &MF =
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createVoidVoidPtrMachineFunction(FunctionID, Module.get(), MMI.get());
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// Saving reserved registers for client.
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return MF.getSubtarget().getRegisterInfo()->getReservedRegs(MF);
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}
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void assembleToStream(const ExegesisTarget &ET,
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std::unique_ptr<llvm::LLVMTargetMachine> TM,
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llvm::ArrayRef<unsigned> LiveIns,
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llvm::ArrayRef<RegisterValue> RegisterInitialValues,
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llvm::ArrayRef<llvm::MCInst> Instructions,
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llvm::raw_pwrite_stream &AsmStream) {
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std::unique_ptr<llvm::LLVMContext> Context =
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llvm::make_unique<llvm::LLVMContext>();
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std::unique_ptr<llvm::Module> Module =
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createModule(Context, TM->createDataLayout());
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std::unique_ptr<llvm::MachineModuleInfo> MMI =
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llvm::make_unique<llvm::MachineModuleInfo>(TM.get());
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llvm::MachineFunction &MF =
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createVoidVoidPtrMachineFunction(FunctionID, Module.get(), MMI.get());
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// We need to instruct the passes that we're done with SSA and virtual
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// registers.
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auto &Properties = MF.getProperties();
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Properties.set(llvm::MachineFunctionProperties::Property::NoVRegs);
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Properties.reset(llvm::MachineFunctionProperties::Property::IsSSA);
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for (const unsigned Reg : LiveIns)
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MF.getRegInfo().addLiveIn(Reg);
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bool IsSnippetSetupComplete = false;
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std::vector<llvm::MCInst> Code =
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generateSnippetSetupCode(ET, TM->getMCSubtargetInfo(),
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RegisterInitialValues, IsSnippetSetupComplete);
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Code.insert(Code.end(), Instructions.begin(), Instructions.end());
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// If the snippet setup is not complete, we disable liveliness tracking. This
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// means that we won't know what values are in the registers.
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if (!IsSnippetSetupComplete)
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Properties.reset(llvm::MachineFunctionProperties::Property::TracksLiveness);
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// prologue/epilogue pass needs the reserved registers to be frozen, this
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// is usually done by the SelectionDAGISel pass.
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MF.getRegInfo().freezeReservedRegs(MF);
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// Fill the MachineFunction from the instructions.
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fillMachineFunction(MF, LiveIns, Code);
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// We create the pass manager, run the passes to populate AsmBuffer.
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llvm::MCContext &MCContext = MMI->getContext();
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llvm::legacy::PassManager PM;
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llvm::TargetLibraryInfoImpl TLII(llvm::Triple(Module->getTargetTriple()));
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PM.add(new llvm::TargetLibraryInfoWrapperPass(TLII));
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llvm::TargetPassConfig *TPC = TM->createPassConfig(PM);
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PM.add(TPC);
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PM.add(MMI.release());
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TPC->printAndVerify("MachineFunctionGenerator::assemble");
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// Add target-specific passes.
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ET.addTargetSpecificPasses(PM);
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TPC->printAndVerify("After ExegesisTarget::addTargetSpecificPasses");
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// Adding the following passes:
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// - machineverifier: checks that the MachineFunction is well formed.
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// - prologepilog: saves and restore callee saved registers.
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for (const char *PassName : {"machineverifier", "prologepilog"})
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if (addPass(PM, PassName, *TPC))
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llvm::report_fatal_error("Unable to add a mandatory pass");
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TPC->setInitialized();
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// AsmPrinter is responsible for generating the assembly into AsmBuffer.
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if (TM->addAsmPrinter(PM, AsmStream, nullptr,
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llvm::TargetMachine::CGFT_ObjectFile, MCContext))
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llvm::report_fatal_error("Cannot add AsmPrinter passes");
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PM.run(*Module); // Run all the passes
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}
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llvm::object::OwningBinary<llvm::object::ObjectFile>
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getObjectFromBuffer(llvm::StringRef InputData) {
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// Storing the generated assembly into a MemoryBuffer that owns the memory.
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std::unique_ptr<llvm::MemoryBuffer> Buffer =
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llvm::MemoryBuffer::getMemBufferCopy(InputData);
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// Create the ObjectFile from the MemoryBuffer.
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std::unique_ptr<llvm::object::ObjectFile> Obj = llvm::cantFail(
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llvm::object::ObjectFile::createObjectFile(Buffer->getMemBufferRef()));
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// Returning both the MemoryBuffer and the ObjectFile.
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return llvm::object::OwningBinary<llvm::object::ObjectFile>(
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std::move(Obj), std::move(Buffer));
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}
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llvm::object::OwningBinary<llvm::object::ObjectFile>
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getObjectFromFile(llvm::StringRef Filename) {
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return llvm::cantFail(llvm::object::ObjectFile::createObjectFile(Filename));
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}
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namespace {
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// Implementation of this class relies on the fact that a single object with a
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// single function will be loaded into memory.
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class TrackingSectionMemoryManager : public llvm::SectionMemoryManager {
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public:
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explicit TrackingSectionMemoryManager(uintptr_t *CodeSize)
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: CodeSize(CodeSize) {}
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uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
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unsigned SectionID,
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llvm::StringRef SectionName) override {
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*CodeSize = Size;
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return llvm::SectionMemoryManager::allocateCodeSection(
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Size, Alignment, SectionID, SectionName);
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}
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private:
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uintptr_t *const CodeSize = nullptr;
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};
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} // namespace
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ExecutableFunction::ExecutableFunction(
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std::unique_ptr<llvm::LLVMTargetMachine> TM,
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llvm::object::OwningBinary<llvm::object::ObjectFile> &&ObjectFileHolder)
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: Context(llvm::make_unique<llvm::LLVMContext>()) {
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assert(ObjectFileHolder.getBinary() && "cannot create object file");
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// Initializing the execution engine.
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// We need to use the JIT EngineKind to be able to add an object file.
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LLVMLinkInMCJIT();
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uintptr_t CodeSize = 0;
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std::string Error;
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ExecEngine.reset(
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llvm::EngineBuilder(createModule(Context, TM->createDataLayout()))
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.setErrorStr(&Error)
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.setMCPU(TM->getTargetCPU())
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.setEngineKind(llvm::EngineKind::JIT)
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.setMCJITMemoryManager(
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llvm::make_unique<TrackingSectionMemoryManager>(&CodeSize))
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.create(TM.release()));
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if (!ExecEngine)
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llvm::report_fatal_error(Error);
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// Adding the generated object file containing the assembled function.
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// The ExecutionEngine makes sure the object file is copied into an
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// executable page.
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ExecEngine->addObjectFile(std::move(ObjectFileHolder));
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// Fetching function bytes.
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FunctionBytes =
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llvm::StringRef(reinterpret_cast<const char *>(
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ExecEngine->getFunctionAddress(FunctionID)),
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CodeSize);
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}
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} // namespace exegesis
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