Add String to List cast in LLVM

Author: Smit-create

src/libasr/codegen/asr_to_llvm.cpp

@@ -4769,6 +4769,65 @@ class ASRToLLVMVisitor : public ASR::BaseVisitor<ASRToLLVMVisitor>
                 tmp = builder->CreateSelect(cmp, zero_str, one_str);
                 break;
             }
+            case (ASR::cast_kindType::CharacterToList) : {
+                llvm::Value *str = CreateLoad(tmp);
+                llvm::AllocaInst *parg = builder->CreateAlloca(character_type, nullptr);
+                LLVM::CreateStore(*builder, str, parg);
+                llvm::Value *str_len = lfortran_str_len(parg);
+                llvm::Type *type = getIntType(4);
+                llvm::AllocaInst *ptr = builder->CreateAlloca(type, nullptr);
+                llvm::Value* i32_one = llvm::ConstantInt::get(context, llvm::APInt(32, 1));
+                LLVM::CreateStore(*builder, i32_one, ptr);
+
+                // Initialize List
+                ASR::List_t* list_type = ASR::down_cast<ASR::List_t>(x.m_type);
+                bool is_array_type_local = false, is_malloc_array_type_local = false;
+                bool is_list_local = false;
+                ASR::dimension_t* m_dims_local = nullptr;
+                int n_dims_local = -1, a_kind_local = -1;
+                llvm::Type* llvm_el_type = get_type_from_ttype_t(list_type->m_type,
+                                            ASR::storage_typeType::Default, is_array_type_local,
+                                            is_malloc_array_type_local, is_list_local, m_dims_local,
+                                            n_dims_local, a_kind_local);
+                std::string type_code = ASRUtils::get_type_code(list_type->m_type);
+                llvm::DataLayout data_layout(module.get());
+                int32_t type_size =  data_layout.getTypeAllocSize(llvm_el_type);
+                llvm::Type* const_list_type = list_api->get_list_type(llvm_el_type, type_code, type_size);
+                llvm::Value* const_list = builder->CreateAlloca(const_list_type, nullptr, "const_list");
+                list_api->list_init(type_code, const_list, *module, 0, 0);
+                uint64_t ptr_loads_copy = ptr_loads;
+                ptr_loads = 1;
+
+                // Create While loop
+                dict_api->set_iterators();
+                llvm::BasicBlock *loophead = llvm::BasicBlock::Create(context, "loop.head");
+                llvm::BasicBlock *loopbody = llvm::BasicBlock::Create(context, "loop.body");
+                llvm::BasicBlock *loopend = llvm::BasicBlock::Create(context, "loop.end");
+                this->current_loophead = loophead;
+                this->current_loopend = loopend;
+                // head
+                start_new_block(loophead);
+                llvm::Value *cond = builder->CreateICmpSLE(LLVM::CreateLoad(*builder, ptr), str_len);
+                builder->CreateCondBr(cond, loopbody, loopend);
+
+                // body
+                start_new_block(loopbody);
+                {
+                    llvm::Value* item = lfortran_str_copy(str, LLVM::CreateLoad(*builder, ptr), LLVM::CreateLoad(*builder, ptr));
+                    list_api->append(const_list, item, list_type->m_type, *module);
+                    // increment ptr by one
+                    LLVM::CreateStore(*builder, builder->CreateAdd(LLVM::CreateLoad(*builder, ptr), i32_one), ptr);
+                }
+                builder->CreateBr(loophead);
+
+                // end
+                start_new_block(loopend);
+                dict_api->reset_iterators();
+
+                ptr_loads = ptr_loads_copy;
+                tmp = const_list;
+                break;
+            }
             default : throw CodeGenError("Cast kind not implemented");
         }
     }