JitFrontend.hpp

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#ifndef PROTEUS_JIT_DEV_HPP
#define PROTEUS_JIT_DEV_HPP
 
#include <llvm/ADT/StringRef.h>
#include <llvm/Bitcode/BitcodeWriter.h>
#include <llvm/IR/IRBuilder.h>
#include <llvm/IR/Module.h>
#include <llvm/IR/Verifier.h>
#include <llvm/Support/Debug.h>
#include <llvm/Support/MemoryBuffer.h>
#include <llvm/TargetParser/Host.h>
#include <llvm/TargetParser/Triple.h>
 
#include <deque>
 
#include "proteus/CoreLLVMDevice.hpp"
#include "proteus/Error.h"
#include "proteus/Frontend/Dispatcher.hpp"
#include "proteus/Frontend/Func.hpp"
#include "proteus/Frontend/LoopNest.hpp"
#include "proteus/Frontend/TypeMap.hpp"
 
#include <iostream>
 
namespace proteus {
using namespace llvm;
 
class JitModule {
private:
  std::unique_ptr<LLVMContext> Ctx;
  std::unique_ptr<Module> Mod;
  std::unique_ptr<CompiledLibrary> Library;
 
  std::deque<std::unique_ptr<FuncBase>> Functions;
  TargetModelType TargetModel;
  std::string TargetTriple;
  Dispatcher &Dispatch;
 
  HashT ModuleHash = 0;
  bool IsCompiled = false;
 
  template <typename... ArgT> struct KernelHandle;
 
  template <typename RetT, typename... ArgT>
  Func<RetT, ArgT...> &buildFuncFromArgsList(FunctionCallee FC,
                                             ArgTypeList<ArgT...>) {
    auto TypedFn = std::make_unique<Func<RetT, ArgT...>>(*this, FC, Dispatch);
    Func<RetT, ArgT...> &TypedFnRef = *TypedFn;
    std::unique_ptr<FuncBase> &Fn = Functions.emplace_back(std::move(TypedFn));
    Fn->declArgs<ArgT...>();
    return TypedFnRef;
  }
 
  template <typename... ArgT>
  KernelHandle<ArgT...> buildKernelFromArgsList(FunctionCallee FC,
                                                ArgTypeList<ArgT...>) {
    auto TypedFn = std::make_unique<Func<void, ArgT...>>(*this, FC, Dispatch);
    Func<void, ArgT...> &TypedFnRef = *TypedFn;
    std::unique_ptr<FuncBase> &Fn = Functions.emplace_back(std::move(TypedFn));
 
    Fn->declArgs<ArgT...>();
 
    setKernel(*Fn);
    return KernelHandle<ArgT...>{TypedFnRef, *this};
  }
 
  template <typename... ArgT> struct KernelHandle {
    Func<void, ArgT...> &F;
    JitModule &M;
 
    void setLaunchBounds([[maybe_unused]] int MaxThreadsPerBlock,
                         [[maybe_unused]] int MinBlocksPerSM = 0) {
      if (!M.isDeviceModule())
        PROTEUS_FATAL_ERROR("Expected a device module for setLaunchBounds");
 
      if (M.isCompiled())
        PROTEUS_FATAL_ERROR("setLaunchBounds must be called before compile()");
 
#if PROTEUS_ENABLE_CUDA || PROTEUS_ENABLE_HIP
      Function *Fn = F.getFunction();
      if (!Fn)
        PROTEUS_FATAL_ERROR("Expected non-null Function");
 
      setLaunchBoundsForKernel(*Fn, MaxThreadsPerBlock, MinBlocksPerSM);
#else
      PROTEUS_FATAL_ERROR("Unsupported target for setLaunchBounds");
#endif
    }
 
    // Launch with type-safety.
    [[nodiscard]] auto launch(LaunchDims Grid, LaunchDims Block,
                              uint64_t ShmemBytes, void *Stream, ArgT... Args) {
      // Pointers to the local parameter copies.
      void *Ptrs[sizeof...(ArgT)] = {(void *)&Args...};
 
      if (!M.isCompiled())
        M.compile();
 
      auto GetKernelFunc = [&]() {
        // Get the kernel func pointer directly from the Func object if
        // available.
        if (auto KernelFunc = F.getCompiledFunc()) {
          return KernelFunc;
        }
 
        // Get the kernel func pointer from the Dispatch and store it to the
        // Func object to avoid cache lookups.
        // TODO: Re-think caching and dispatchers.
        auto KernelFunc = reinterpret_cast<decltype(F.getCompiledFunc())>(
            M.Dispatch.getFunctionAddress(F.getName(), M.ModuleHash,
                                          M.getLibrary()));
 
        F.setCompiledFunc(KernelFunc);
 
        return KernelFunc;
      };
 
      return M.Dispatch.launch(reinterpret_cast<void *>(GetKernelFunc()), Grid,
                               Block, Ptrs, ShmemBytes, Stream);
    }
 
    FuncBase *operator->() { return &F; }
  };
 
  bool isDeviceModule() {
    return ((TargetModel == TargetModelType::CUDA) ||
            (TargetModel == TargetModelType::HIP));
  }
 
  void setKernel(FuncBase &F) {
    switch (TargetModel) {
    case TargetModelType::CUDA: {
      NamedMDNode *MD = Mod->getOrInsertNamedMetadata("nvvm.annotations");
 
      Metadata *MDVals[] = {
          ConstantAsMetadata::get(F.getFunction()),
          MDString::get(*Ctx, "kernel"),
          ConstantAsMetadata::get(ConstantInt::get(Type::getInt32Ty(*Ctx), 1))};
      // Append metadata to nvvm.annotations.
      MD->addOperand(MDNode::get(*Ctx, MDVals));
 
      // Add a function attribute for the kernel.
      F.getFunction()->addFnAttr(Attribute::get(*Ctx, "kernel"));
      return;
    }
    case TargetModelType::HIP:
      F.getFunction()->setCallingConv(CallingConv::AMDGPU_KERNEL);
      return;
    case TargetModelType::HOST:
      PROTEUS_FATAL_ERROR("Host does not support setKernel");
    default:
      PROTEUS_FATAL_ERROR("Unsupported target " + TargetTriple);
    }
  }
 
public:
  JitModule(StringRef Target = "host")
      : Ctx{std::make_unique<LLVMContext>()},
        Mod{std::make_unique<Module>("JitModule", *Ctx)},
        TargetModel{parseTargetModel(Target)},
        TargetTriple(getTargetTriple(TargetModel)),
        Dispatch(Dispatcher::getDispatcher(TargetModel)) {}
 
  // Disable copy and move constructors.
  JitModule(const JitModule &) = delete;
  JitModule &operator=(const JitModule &) = delete;
  JitModule(JitModule &&) = delete;
  JitModule &operator=(JitModule &&) = delete;
 
  template <typename Sig> auto &addFunction(StringRef Name) {
    using RetT = typename FnSig<Sig>::RetT;
    using ArgT = typename FnSig<Sig>::ArgsTList;
 
    if (IsCompiled)
      PROTEUS_FATAL_ERROR(
          "The module is compiled, no further code can be added");
 
    Mod->setTargetTriple(TargetTriple);
    FunctionCallee FC = getFunctionCallee<RetT>(Name, ArgT{});
 
    Function *F = dyn_cast<Function>(FC.getCallee());
    if (!F)
      PROTEUS_FATAL_ERROR("Unexpected");
 
    return buildFuncFromArgsList<RetT>(FC, ArgT{});
  }
 
  bool isCompiled() const { return IsCompiled; }
 
  const Module &getModule() const { return *Mod; }
 
  template <typename Sig> auto addKernel(StringRef Name) {
    using RetT = typename FnSig<Sig>::RetT;
    static_assert(std::is_void_v<RetT>, "Kernels must have void return type");
    using ArgT = typename FnSig<Sig>::ArgsTList;
 
    if (IsCompiled)
      PROTEUS_FATAL_ERROR(
          "The module is compiled, no further code can be added");
 
    if (!isDeviceModule())
      PROTEUS_FATAL_ERROR("Expected a device module for addKernel");
 
    Mod->setTargetTriple(TargetTriple);
    FunctionCallee FC = getFunctionCallee<void>(Name, ArgT{});
    Function *F = dyn_cast<Function>(FC.getCallee());
    if (!F)
      PROTEUS_FATAL_ERROR("Unexpected");
 
    return buildKernelFromArgsList(FC, ArgT{});
  }
 
  void compile(bool Verify = false) {
    if (IsCompiled)
      return;
 
    if (Verify)
      if (verifyModule(*Mod, &errs())) {
        PROTEUS_FATAL_ERROR("Broken module found, JIT compilation aborted!");
      }
 
    SmallVector<char, 0> Buffer;
    raw_svector_ostream OS(Buffer);
    WriteBitcodeToFile(*Mod, OS);
 
    // Create a unique module hash based on the bitcode and append to all
    // function names to make them unique.
    // TODO: Is this necessary?
    ModuleHash = hash(StringRef{Buffer.data(), Buffer.size()});
    for (auto &JitF : Functions) {
      JitF->setName(JitF->getName().str() + "$" + ModuleHash.toString());
    }
 
    if ((Library = Dispatch.lookupCompiledLibrary(ModuleHash))) {
      IsCompiled = true;
      return;
    }
 
    Library = std::make_unique<CompiledLibrary>(
        Dispatch.compile(std::move(Ctx), std::move(Mod), ModuleHash));
    IsCompiled = true;
  }
 
  HashT getModuleHash() const { return ModuleHash; }
 
  Dispatcher &getDispatcher() const { return Dispatch; }
 
  TargetModelType getTargetModel() const { return TargetModel; }
 
  CompiledLibrary &getLibrary() {
    if (!IsCompiled)
      compile();
 
    if (!Library)
      PROTEUS_FATAL_ERROR("Expected non-null library after compilation");
 
    return *Library;
  }
 
  template <typename RetT, typename... ArgT>
  FunctionCallee getFunctionCallee(StringRef Name, ArgTypeList<ArgT...>) {
    return Mod->getOrInsertFunction(Name, TypeMap<RetT>::get(*Ctx),
                                    TypeMap<ArgT>::get(*Ctx)...);
  }
 
  void print() { Mod->print(outs(), nullptr); }
};
 
template <typename Sig>
std::enable_if_t<!std::is_void_v<typename FnSig<Sig>::RetT>, Var &>
FuncBase::call(StringRef Name) {
  using RetT = typename FnSig<Sig>::RetT;
  auto *F = getFunction();
  LLVMContext &Ctx = F->getContext();
 
  using RetT = typename FnSig<Sig>::RetT;
  using ArgT = typename FnSig<Sig>::ArgsTList;
  FunctionCallee Callee = J.getFunctionCallee<RetT>(Name, ArgT{});
  auto *Call = IRB.CreateCall(Callee);
  Var &Ret = declVarInternal("ret", TypeMap<RetT>::get(Ctx));
  Ret.storeValue(Call);
  return Ret;
}
 
template <typename Sig>
std::enable_if_t<std::is_void_v<typename FnSig<Sig>::RetT>, void>
FuncBase::call(StringRef Name) {
  using RetT = typename FnSig<Sig>::RetT;
 
  using RetT = typename FnSig<Sig>::RetT;
  using ArgT = typename FnSig<Sig>::ArgsTList;
  FunctionCallee Callee = J.getFunctionCallee<RetT>(Name, ArgT{});
  IRB.CreateCall(Callee);
}
 
template <typename Sig, typename... ArgVars>
std::enable_if_t<!std::is_void_v<typename FnSig<Sig>::RetT>, Var &>
FuncBase::call(StringRef Name, ArgVars &&...ArgsVars) {
  auto *F = getFunction();
  LLVMContext &Ctx = F->getContext();
 
  using RetT = typename FnSig<Sig>::RetT;
  using ArgT = typename FnSig<Sig>::ArgsTList;
  FunctionCallee Callee = J.getFunctionCallee<RetT>(Name, ArgT{});
  auto *Call = IRB.CreateCall(Callee, {ArgsVars.getValue()...});
 
  Var &Ret = declVarInternal("ret", TypeMap<RetT>::get(Ctx));
  Ret.storeValue(Call);
  return Ret;
}
 
template <typename Sig, typename... ArgVars>
std::enable_if_t<std::is_void_v<typename FnSig<Sig>::RetT>, void>
FuncBase::call(StringRef Name, ArgVars &&...ArgsVars) {
  using RetT = typename FnSig<Sig>::RetT;
  using ArgT = typename FnSig<Sig>::ArgsTList;
 
  FunctionCallee Callee = J.getFunctionCallee<RetT>(Name, ArgT{});
  IRB.CreateCall(Callee, {ArgsVars.getValue()...});
}
 
template <typename RetT, typename... ArgT>
RetT Func<RetT, ArgT...>::operator()(ArgT... Args) {
  if (!J.isCompiled())
    J.compile();
 
  if (!CompiledFunc) {
    CompiledFunc = reinterpret_cast<decltype(CompiledFunc)>(
        J.getDispatcher().getFunctionAddress(getName(), J.getModuleHash(),
                                             J.getLibrary()));
  }
 
  if (J.getTargetModel() != TargetModelType::HOST)
    PROTEUS_FATAL_ERROR(
        "Target is a GPU model, cannot directly run functions, use launch()");
 
  if constexpr (std::is_void_v<RetT>)
    Dispatch.run<RetT(ArgT...)>(reinterpret_cast<void *>(CompiledFunc),
                                Args...);
  else
    return Dispatch.run<RetT(ArgT...)>(reinterpret_cast<void *>(CompiledFunc),
                                       Args...);
}
 
} // namespace proteus
 
#endif