optimize local array init

.vscode/launch.json

@@ -9,7 +9,7 @@
             "request": "launch",
             "name": "Debug",
             "program": "${workspaceFolder}/build/sysy",
-            "args": ["../sysytests/functional_2022/21_if_test2.sy", "-S", "-o", "build/21_my.ll", "-O1", "-emit-llvm"],
+            "args": ["../sysytests/functional_2022/34_arr_expr_len.sy", "-S", "-o", "build/21_my.ll", "-O1", "-emit-llvm"],
             "cwd": "${workspaceFolder}"
         }
     ]

include/common.h

@@ -1,5 +1,6 @@
 #pragma once
 #include "3rdparty/easylogging++.h"
+#include "fmt/core.h"
 #include <algorithm>
 #include <any>
 #include <bitset>

include/llir_value.h

@@ -199,6 +199,7 @@ public:
 
 class ConstantArr : public Constant {
 public:
+  //! By default, this value_list is flattened and with size equal to declared size
   std::vector<ValuePtr_t> value_list;
   ConstantArr(const std::string &name, const std::vector<ValuePtr_t> &value_list, std::shared_ptr<ArrayType> type)
     : Constant(name, type), value_list(value_list) {}

src/visitor.cpp

@@ -67,7 +67,6 @@ void _sysy_stoptime(int lineno);
 */
 
 Visitor::Visitor(SysyLexer &) {
-#pragma region RegisterLibFunc
   auto fparam_i32     = std::make_shared<FParam>("", TypeHelper::TYPE_I32);
   auto pointer_type   = std::make_shared<PointerType>(TypeHelper::TYPE_I32);
   auto fparam_ptr_i32 = std::make_shared<FParam>("", pointer_type);
@@ -107,7 +106,9 @@ Visitor::Visitor(SysyLexer &) {
   func_stoptime->fparam_list = {fparam_i32};
   _func_tab.push_name("stoptime", func_stoptime);
 
-#pragma endregion
+  auto func_memset         = std::make_shared<Function>("memset", TypeHelper::TYPE_VOID);
+  func_memset->fparam_list = {fparam_ptr_i32, fparam_i32, fparam_i32};
+  _func_tab.push_name("memset", func_memset);
 }
 
 std::any Visitor::visitConstDecl(SysyParser::ConstDeclContext *ctx) {
@@ -235,11 +236,17 @@ std::any Visitor::visitVarDef(SysyParser::VarDefContext *ctx) {
         for (int i = 1; i < dim_list.size(); ++i) {
           base_ptr = build_InstGEP(base_ptr, {CONST0, CONST0}, _state.current_bb);
         }
+        auto inst_call = build_InstCall(
+          _func_tab.get_name("memset").value(),
+          {base_ptr, CONST0, ConstantInt::make_shared(array_value.size() * 4)},
+          _state.current_bb
+        );
         // TODO: BAAU-2021 calls memset in `libc` (not sysylib) to optimize this process
-        build_InstStore(array_value[0] ? array_value[0] : CONST0, base_ptr, _state.current_bb);
+        if (array_value[0]) build_InstStore(array_value[0], base_ptr, _state.current_bb);
         for (int i = 1; i < array_value.size(); ++i) {
+          if (!array_value[i]) continue;
           auto ptr = build_InstGEP(base_ptr, {ConstantInt::make_shared(i)}, _state.current_bb);
-          build_InstStore(array_value[i] ? array_value[i] : CONST0, ptr, _state.current_bb);
+          build_InstStore(array_value[i], ptr, _state.current_bb);
         }
       }
       // If there is no init expr, let it be
@@ -288,18 +295,10 @@ std::any Visitor::visitInitVal(SysyParser::InitValContext *ctx) {
     }
     for (auto init_val : ctx->initVal()) {
       if (init_val->exp()) {
-        if (_state.isGlobalIint) {
-          auto const_value = any_to_Value(visitInitVal(init_val));
-          // should evaluate to const int
-          sysy_assert(Value::is<ConstantInt>(const_value));
-          cur_arr.push_back(const_value);
-        }
-        else {
-          // God knows what it evaluates to
         auto exp_value = any_to_Value(visitInitVal(init_val));
+        if (_state.isGlobalIint) assert(Value::is<ConstantInt>(exp_value));
         cur_arr.push_back(exp_value);
       }
-      }
       else {
         // evaluate sub-array
         // before evaluate the new sub-array, first fill up the last one
@@ -614,7 +613,6 @@ std::any Visitor::visitUnaryExp(SysyParser::UnaryExpContext *ctx) {
     }
     else if (ctx->IDENT()) {
       // Fucntion call
-      // TODO: buildCall/isRealParam
       // TODO: Handle string & putf()
       auto func_name = ctx->IDENT()->getText();
       VLOG(5) << "Calling Func: " << func_name;

src/visitor_llir_gen.cpp

@@ -11,8 +11,8 @@
 
 namespace CompSysY {
 
-const std::array<std::string, 8> libfunc_list =
+const std::array<std::string, 9> libfunc_list =
-  {"getint", "getch", "getarray", "putint", "putch", "putarray", "starttime", "stoptime"};
+  {"getint", "getch", "getarray", "putint", "putch", "putarray", "starttime", "stoptime", "memset"};
 
 // On generation, the array is flattened, thus we have to calculate them
 std::shared_ptr<ConstantArr> gen_arr_hierarchy(