Method CodegenCopyGroupingValues

be/src/exec/grouping-aggregator.cc:1299–1361

Codegen for CopyGroupingValues Example IR for (group by int_col, string_col): (mangled function names have been shortened) define void @CopyGroupingValues(%"class.impala::GroupingAggregator"* %this_ptr, %"class.impala::Tuple"* %intermediate_tuple, i8* %buffer) { entry: call void @_ZN6impala18GroupingAggregator30CopyGroupingValuesFixedLenSlot... (%"class.impala::GroupingAggregator"* %this_ptr, %"c

 //   ret void
 // }
Status GroupingAggregatorConfig::CodegenCopyGroupingValues(LlvmCodeGen* codegen,
      llvm::Function** fn) {
  llvm::PointerType* this_ptr_type = codegen->GetStructPtrType<GroupingAggregator>();
  llvm::PointerType* tuple_ptr_type = codegen->GetStructPtrType<Tuple>();
  LlvmCodeGen::FnPrototype prototype(codegen, "CopyGroupingValues",
      codegen->void_type());
  prototype.AddArgument(LlvmCodeGen::NamedVariable("this_ptr", this_ptr_type));
  prototype.AddArgument(
      LlvmCodeGen::NamedVariable("intermediate_tuple", tuple_ptr_type));
  prototype.AddArgument(LlvmCodeGen::NamedVariable("buffer", codegen->ptr_type()));

  llvm::LLVMContext& context = codegen->context();
  LlvmBuilder builder(context);
  llvm::Value* args[3];
  *fn = prototype.GeneratePrototype(&builder, args);

  llvm::Value* this_ptr = args[0];
  llvm::Value* intermediate_tuple = args[1];
  llvm::Value* buffer = args[2];

  // Copy fixed len slots
  for (int i = 0; i < grouping_exprs_.size(); ++i) {
    // Get relevant data from slot desc as consts
    SlotDescriptor* slot_desc = intermediate_tuple_desc_->slots()[i];
    llvm::Value* idx = codegen->GetI32Constant(i);
    llvm::Value* tuple_offset = codegen->GetI32Constant(slot_desc->tuple_offset());
    llvm::Value* slot_size = codegen->GetI32Constant(slot_desc->slot_size());

    llvm::Value* null_indicator_offset =
        slot_desc->null_indicator_offset().ToIRPacked(codegen);

    // call CopyGroupingValuesFixedLenSlot
    codegen->CodegenCallFunction(&builder,
        IRFunction::GROUPING_AGG_COPY_GROUPING_VALUES_FIXED_LEN_SLOT,
        {this_ptr, intermediate_tuple, idx, null_indicator_offset, tuple_offset,
         slot_size});
  }

  // Copy var len string data
  for (int expr_idx : string_grouping_exprs_) {
    // Get relevant data from slot desc as consts
    SlotDescriptor* slot_desc = intermediate_tuple_desc_->slots()[expr_idx];
    llvm::Value* tuple_offset = codegen->GetI32Constant(slot_desc->tuple_offset());
    llvm::Value* idx = codegen->GetI32Constant(expr_idx);

    // call CopyGroupingValuesStringSlot
    llvm::Value* bytes_copied = codegen->CodegenCallFunction(&builder,
        IRFunction::GROUPING_AGG_COPY_GROUPING_VALUES_STRING_SLOT,
        {this_ptr, intermediate_tuple, idx, tuple_offset, buffer}, "bytes_copied");

    // increase buffer by bytes copied
    buffer = builder.CreateGEP(buffer, bytes_copied, "buffer");
  }

  builder.CreateRetVoid();

  *fn = codegen->FinalizeFunction(*fn);
  if (*fn == nullptr) {