//===- KaleidoscopeJIT.h - A simple JIT for Kaleidoscope --------*- 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
//
//===----------------------------------------------------------------------===//
//
// Contains a simple JIT definition for use in the kaleidoscope tutorials.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H
#define LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H

#include "llvm/ADT/StringRef.h"
#include "llvm/ExecutionEngine/JITSymbol.h"
#include "llvm/ExecutionEngine/Orc/CompileOnDemandLayer.h"
#include "llvm/ExecutionEngine/Orc/CompileUtils.h"
#include "llvm/ExecutionEngine/Orc/Core.h"
#include "llvm/ExecutionEngine/Orc/EPCIndirectionUtils.h"
#include "llvm/ExecutionEngine/Orc/ExecutionUtils.h"
#include "llvm/ExecutionEngine/Orc/ExecutorProcessControl.h"
#include "llvm/ExecutionEngine/Orc/IRCompileLayer.h"
#include "llvm/ExecutionEngine/Orc/IRTransformLayer.h"
#include "llvm/ExecutionEngine/Orc/JITTargetMachineBuilder.h"
#include "llvm/ExecutionEngine/Orc/RTDyldObjectLinkingLayer.h"
#include "llvm/ExecutionEngine/SectionMemoryManager.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/Transforms/InstCombine/InstCombine.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Scalar/GVN.h"
#include <memory>

class PrototypeAST;
class ExprAST;

/// FunctionAST - This class represents a function definition itself.
class FunctionAST {
  std::unique_ptr<PrototypeAST> Proto;
  std::unique_ptr<ExprAST> Body;

public:
  FunctionAST(std::unique_ptr<PrototypeAST> Proto,
              std::unique_ptr<ExprAST> Body)
      : Proto(std::move(Proto)), Body(std::move(Body)) {}

  const PrototypeAST& getProto() const;
  const std::string& getName() const;
  llvm::Function *codegen();
};

/// This will compile FnAST to IR, rename the function to add the given
/// suffix (needed to prevent a name-clash with the function's stub),
/// and then take ownership of the module that the function was compiled
/// into.
llvm::orc::ThreadSafeModule irgenAndTakeOwnership(FunctionAST &FnAST,
                                                  const std::string &Suffix);

namespace llvm {
namespace orc {

class KaleidoscopeASTLayer;
class KaleidoscopeJIT;

class KaleidoscopeASTMaterializationUnit : public MaterializationUnit {
public:
  KaleidoscopeASTMaterializationUnit(KaleidoscopeASTLayer &L,
                                     std::unique_ptr<FunctionAST> F);

  StringRef getName() const override {
    return "KaleidoscopeASTMaterializationUnit";
  }

  void materialize(std::unique_ptr<MaterializationResponsibility> R) override;

private:
  void discard(const JITDylib &JD, const SymbolStringPtr &Sym) override {
    llvm_unreachable("Kaleidoscope functions are not overridable");
  }

  KaleidoscopeASTLayer &L;
  std::unique_ptr<FunctionAST> F;
};

class KaleidoscopeASTLayer {
public:
  KaleidoscopeASTLayer(IRLayer &BaseLayer, const DataLayout &DL)
      : BaseLayer(BaseLayer), DL(DL) {}

  Error add(ResourceTrackerSP RT, std::unique_ptr<FunctionAST> F) {
    return RT->getJITDylib().define(
        std::make_unique<KaleidoscopeASTMaterializationUnit>(*this,
                                                             std::move(F)),
        RT);
  }

  void emit(std::unique_ptr<MaterializationResponsibility> MR,
            std::unique_ptr<FunctionAST> F) {
    BaseLayer.emit(std::move(MR), irgenAndTakeOwnership(*F, ""));
  }

  MaterializationUnit::Interface getInterface(FunctionAST &F) {
    MangleAndInterner Mangle(BaseLayer.getExecutionSession(), DL);
    SymbolFlagsMap Symbols;
    Symbols[Mangle(F.getName())] =
        JITSymbolFlags(JITSymbolFlags::Exported | JITSymbolFlags::Callable);
    return MaterializationUnit::Interface(std::move(Symbols), nullptr);
  }

private:
  IRLayer &BaseLayer;
  const DataLayout &DL;
};

KaleidoscopeASTMaterializationUnit::KaleidoscopeASTMaterializationUnit(
    KaleidoscopeASTLayer &L, std::unique_ptr<FunctionAST> F)
    : MaterializationUnit(L.getInterface(*F)), L(L), F(std::move(F)) {}

void KaleidoscopeASTMaterializationUnit::materialize(
    std::unique_ptr<MaterializationResponsibility> R) {
  L.emit(std::move(R), std::move(F));
}

class KaleidoscopeJIT {
private:
  std::unique_ptr<ExecutionSession> ES;
  std::unique_ptr<EPCIndirectionUtils> EPCIU;

  DataLayout DL;
  MangleAndInterner Mangle;

  RTDyldObjectLinkingLayer ObjectLayer;
  IRCompileLayer CompileLayer;
  IRTransformLayer OptimizeLayer;
  KaleidoscopeASTLayer ASTLayer;

  JITDylib &MainJD;

  static void handleLazyCallThroughError() {
    errs() << "LazyCallThrough error: Could not find function body";
    exit(1);
  }

public:
  KaleidoscopeJIT(std::unique_ptr<ExecutionSession> ES,
                  std::unique_ptr<EPCIndirectionUtils> EPCIU,
                  JITTargetMachineBuilder JTMB, DataLayout DL)
      : ES(std::move(ES)), EPCIU(std::move(EPCIU)), DL(std::move(DL)),
        Mangle(*this->ES, this->DL),
        ObjectLayer(*this->ES,
                    []() { return std::make_unique<SectionMemoryManager>(); }),
        CompileLayer(*this->ES, ObjectLayer,
                     std::make_unique<ConcurrentIRCompiler>(std::move(JTMB))),
        OptimizeLayer(*this->ES, CompileLayer, optimizeModule),
        ASTLayer(OptimizeLayer, this->DL),
        MainJD(this->ES->createBareJITDylib("<main>")) {
    MainJD.addGenerator(
        cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
            DL.getGlobalPrefix())));
  }

  ~KaleidoscopeJIT() {
    if (auto Err = ES->endSession())
      ES->reportError(std::move(Err));
    if (auto Err = EPCIU->cleanup())
      ES->reportError(std::move(Err));
  }

  static Expected<std::unique_ptr<KaleidoscopeJIT>> Create() {
    auto EPC = SelfExecutorProcessControl::Create();
    if (!EPC)
      return EPC.takeError();

    auto ES = std::make_unique<ExecutionSession>(std::move(*EPC));

    auto EPCIU = EPCIndirectionUtils::Create(ES->getExecutorProcessControl());
    if (!EPCIU)
      return EPCIU.takeError();

    (*EPCIU)->createLazyCallThroughManager(
        *ES, pointerToJITTargetAddress(&handleLazyCallThroughError));

    if (auto Err = setUpInProcessLCTMReentryViaEPCIU(**EPCIU))
      return std::move(Err);

    JITTargetMachineBuilder JTMB(
        ES->getExecutorProcessControl().getTargetTriple());

    auto DL = JTMB.getDefaultDataLayoutForTarget();
    if (!DL)
      return DL.takeError();

    return std::make_unique<KaleidoscopeJIT>(std::move(ES), std::move(*EPCIU),
                                             std::move(JTMB), std::move(*DL));
  }

  const DataLayout &getDataLayout() const { return DL; }

  JITDylib &getMainJITDylib() { return MainJD; }

  Error addModule(ThreadSafeModule TSM, ResourceTrackerSP RT = nullptr) {
    if (!RT)
      RT = MainJD.getDefaultResourceTracker();

    return OptimizeLayer.add(RT, std::move(TSM));
  }

  Error addAST(std::unique_ptr<FunctionAST> F, ResourceTrackerSP RT = nullptr) {
    if (!RT)
      RT = MainJD.getDefaultResourceTracker();
    return ASTLayer.add(RT, std::move(F));
  }

  Expected<JITEvaluatedSymbol> lookup(StringRef Name) {
    return ES->lookup({&MainJD}, Mangle(Name.str()));
  }

private:
  static Expected<ThreadSafeModule>
  optimizeModule(ThreadSafeModule TSM, const MaterializationResponsibility &R) {
    TSM.withModuleDo([](Module &M) {
      // Create a function pass manager.
      auto FPM = std::make_unique<legacy::FunctionPassManager>(&M);

      // Add some optimizations.
      FPM->add(createInstructionCombiningPass());
      FPM->add(createReassociatePass());
      FPM->add(createGVNPass());
      FPM->add(createCFGSimplificationPass());
      FPM->doInitialization();

      // Run the optimizations over all functions in the module being added to
      // the JIT.
      for (auto &F : M)
        FPM->run(F);
    });

    return std::move(TSM);
  }
};

} // end namespace orc
} // end namespace llvm

#endif // LLVM_EXECUTIONENGINE_ORC_KALEIDOSCOPEJIT_H