Method GetCodegendComputeFnImpl

be/src/exprs/valid-tuple-id.cc:118–167

Sample IR output (with 3 tuple ids in the vector): define i64 @ValidTupleId(%"class.impala::ScalarExprEvaluator"* %eval, %"class.impala::TupleRow"* %row) #48 { entry: %0 = alloca i64 %1 = alloca i64 %2 = alloca i64 %tuple_row_ptr = getelementptr inbounds %"class.impala::TupleRow", %"class.impala::TupleRow"* %row, i32 0 %tuple_ptr = bitcast %"class.impala::TupleRow"* %tuple_row_ptr to %"class.impa

// }
//
Status ValidTupleIdExpr::GetCodegendComputeFnImpl(
    LlvmCodeGen* codegen, llvm::Function** fn) {
  // Create a method with the expected signature.
  llvm::Value* args[2];
  llvm::Function* new_fn = CreateIrFunctionPrototype("ValidTupleId", codegen, &args);
  llvm::LLVMContext& context = codegen->context();
  llvm::BasicBlock* entry_block = llvm::BasicBlock::Create(context, "entry", new_fn);
  LlvmBuilder builder(entry_block);
  llvm::Value* row_ptr = args[1];

  // Unroll the loop.
  for (uint32_t i = 0; i < tuple_ids_.size(); i++) {
    // Get the i'th Tuple* from the row.
    llvm::Value* tuple_row_ptr =
        builder.CreateInBoundsGEP(row_ptr, codegen->GetI32Constant(i), "tuple_row_ptr");
    // Cast to Tuple**
    llvm::Type* tuple_ptr_ptr_type =
        codegen->GetPtrType(codegen->GetNamedPtrType(Tuple::LLVM_CLASS_NAME));
    llvm::Value* tuple_ptr_ptr =
        builder.CreateBitCast(tuple_row_ptr, tuple_ptr_ptr_type, "tuple_ptr_ptr");
    // Get the Tuple* and compare to nullptr.
    llvm::Value* tuple_ptr = builder.CreateLoad(tuple_ptr_ptr, "tuple_ptr");
    llvm::Value* is_not_null = builder.CreateIsNotNull(tuple_ptr, "is_not_null");

    // Create a conditional on the result.
    llvm::BasicBlock* next = llvm::BasicBlock::Create(context, "next", new_fn);
    llvm::BasicBlock* ret_block = llvm::BasicBlock::Create(context, "return", new_fn);
    builder.CreateCondBr(is_not_null, ret_block, next);

    // Add code to the block that is executed if the Tuple* was not a nullptr.
    builder.SetInsertPoint(ret_block);
    // Generate code returning an IntVal containing the tuple id.
    CodegenAnyVal result(codegen, &builder, ColumnType(TYPE_INT), nullptr, "ret");
    llvm::Constant* tuple_id =
        codegen->GetI32Constant(static_cast<uint64_t>(tuple_ids_[i]));
    result.SetVal(tuple_id);
    builder.CreateRet(result.GetLoweredValue());

    // Add code to the  block that is executed if the Tuple* was null.
    builder.SetInsertPoint(next);
  }
  // We fell out of the loop, return null.
  builder.CreateRet(CodegenAnyVal::GetNullVal(codegen, type()));

  *fn = codegen->FinalizeFunction(new_fn);
  if (UNLIKELY(*fn == nullptr)) {
    return Status(TErrorCode::IR_VERIFY_FAILED, "ValidTupleId");
  }
  return Status::OK();
}

string ValidTupleIdExpr::DebugString() const {
  return "ValidTupleId()";