CuPBoP/compilation/KernelTranslation/lib/generate_x86_format.cpp

#include "generate_x86_format.h"
#include "tool.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/IRReader/IRReader.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Transforms/Utils/ValueMapper.h"
#include <iostream>

using namespace llvm;

void set_meta_data(llvm::Module *M) {
  M->setTargetTriple("x86_64-unknown-linux-gnu");
  M->setDataLayout(
      "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128");
}

// as pthread only accept a single void* for input
// we have to decode this input inside the kernel
void decode_input(llvm::Module *M) {

  std::set<llvm::Function *> need_remove;

  LLVMContext *C = &M->getContext();
  llvm::Type *Int32T = Type::getInt32Ty(*C);
  llvm::Type *Int8T = Type::getInt8Ty(*C);

  llvm::FunctionType *LauncherFuncT = FunctionType::get(
      Type::getVoidTy(*C), {PointerType::get(Int8T, 0)}, false);

  std::set<GlobalVariable *> dynmaic_memory;

  std::map<GlobalVariable *, Value *> corres_dynamic_memory_load_address;

  // generate Wrapper Function type
  // now we only support a single int32*
  for (Module::iterator i = M->begin(), e = M->end(); i != e; ++i) {
    Function *F = &(*i);
    if (!isKernelFunction(M, F))
      continue;
    auto func_name = F->getName().str();
    llvm::IRBuilder<> Builder(M->getContext());

    FunctionCallee fc =
        M->getOrInsertFunction(func_name + "_wrapper", LauncherFuncT);
    Function *WorkGroup = dyn_cast<Function>(fc.getCallee());

    BasicBlock *Block = BasicBlock::Create(M->getContext(), "", WorkGroup);
    Builder.SetInsertPoint(Block);

    // WorkGroup has only a single input
    Function::arg_iterator ai = WorkGroup->arg_begin();

    SmallVector<Value *, 8> Arguments;
    Value *input_arg = &*ai;
    // convert to int**
    input_arg = Builder.CreateBitOrPointerCast(
        input_arg, PointerType::get(PointerType::get(Int32T, 0), 0));

    // dynamic memory load in the wrapper function
    GlobalVariable *share_memory = M->getGlobalVariable("wrapper_global_data");
    if (share_memory != NULL) {
      dynmaic_memory.insert(share_memory);
      llvm::GlobalVariable *global_mem = new llvm::GlobalVariable(
          *M, Int32T, false, llvm::GlobalValue::ExternalLinkage, NULL,
          "thread_memory_size", NULL, llvm::GlobalValue::GeneralDynamicTLSModel,
          0, false);
      Value *loadedValue = Builder.CreateLoad(global_mem);

      llvm::FunctionType *LaunchFun2 = FunctionType::get(
          PointerType::get(PointerType::get(Int32T, 0), 0), NULL);

      FunctionCallee fc2 =
          M->getOrInsertFunction("_wrapper_global_data", LaunchFun2);

      Function *WorkGroup2 = dyn_cast<Function>(fc2.getCallee());

      WorkGroup2->setLinkage(GlobalValue::WeakODRLinkage);
      WorkGroup2->setVisibility(GlobalValue::HiddenVisibility);
      Comdat *co = M->getOrInsertComdat("_wrapper_global_data");
      co->setSelectionKind(Comdat::SelectionKind::Any);
      WorkGroup2->setComdat(co);

      BasicBlock *Block2 = BasicBlock::Create(M->getContext(), "", WorkGroup2);

      llvm::IRBuilder<> Builder2(M->getContext());
      Builder2.SetInsertPoint(Block2);
      Builder2.CreateRet(share_memory);

      auto PT = dyn_cast<PointerType>(share_memory->getType());
      auto element_type = PT->getElementType();
      // std::cout << element_type->getTypeID()  << " Got global memor $$$$$$"
      // << share_memory->getName().str() << std::endl;

      AllocaInst *new_arr = Builder.CreateAlloca(Int8T, loadedValue, "new_arr");
      // new_arr->setAlignment(llvm::MaybeAlign(16));
      Value *new_ar = new_arr;
      Value *gptr = Builder.CreateBitOrPointerCast(
          share_memory, PointerType::get(PointerType::get(Int8T, 0), 0));

      Builder.CreateStore(new_ar, gptr);
    }

    size_t idx = 0;
    for (Function::const_arg_iterator ii = F->arg_begin(), ee = F->arg_end();
         ii != ee; ++ii) {
      Type *ArgType = ii->getType();

      // calculate addr
      Value *GEP = Builder.CreateGEP(input_arg, ConstantInt::get(Int32T, idx));
      // load corresponding int*
      GEP = Builder.CreateLoad(GEP);
      // bitcast
      GEP = Builder.CreateBitOrPointerCast(GEP, PointerType::get(ArgType, 0));
      Value *Arg = Builder.CreateLoad(GEP);
      Arguments.push_back(Arg);
      ++idx;
    }

    CallInst *c = Builder.CreateCall(F, ArrayRef<llvm::Value *>(Arguments));
    Builder.CreateRetVoid();
  }
  for (auto f : need_remove) {
    f->dropAllReferences();
    f->eraseFromParent();
  }
}

void remove_barrier(llvm::Module *M) {
  std::vector<Instruction *> need_remove;
  for (auto F = M->begin(); F != M->end(); ++F)
    for (auto BB = F->begin(); BB != F->end(); ++BB) {
      for (auto BI = BB->begin(); BI != BB->end(); BI++) {
        if (auto Call = dyn_cast<CallInst>(BI)) {
          if (Call->isInlineAsm())
            continue;
          auto func_name = Call->getCalledFunction()->getName().str();
          if (func_name == "llvm.nvvm.bar.warp.sync" ||
              func_name == "llvm.nvvm.barrier0" ||
              func_name == "llvm.nvvm.barrier.sync") {
            need_remove.push_back(Call);
          }
        }
      }
    }
  for (auto inst : need_remove) {
    inst->eraseFromParent();
  }
}

void remove_useless_var(llvm::Module *M) {
  M->getGlobalVariable("intra_warp_index")->eraseFromParent();
  M->getGlobalVariable("inter_warp_index")->eraseFromParent();
}

void generate_x86_format(llvm::Module *M) {
  // change metadata
  set_meta_data(M);
  // decode argument
  decode_input(M);
  // remove barrier
  remove_barrier(M);
  // remove useless func/variable
  remove_useless_var(M);
}