diff --git a/src/IR.h b/src/IR.h
index f54205a..97d3f79 100644
--- a/src/IR.h
+++ b/src/IR.h
@@ -8,6 +8,7 @@
 #include <map>
 #include <memory>
 #include <string>
+#include <type_traits>
 #include <vector>
 
 namespace sysy {
@@ -65,6 +66,10 @@ public:
   bool isPointer() const { return kind == kPointer; }
   bool isFunction() const { return kind == kFunction; }
   int getSize() const;
+  template <typename T>
+  std::enable_if_t<std::is_base_of_v<Type, T>, T *> as() const {
+    return dynamic_cast<T *>(const_cast<Type *>(this));
+  }
 }; // class Type
 
 //! Pointer type
@@ -196,15 +201,15 @@ public:
 class ConstantValue : public Value {
 protected:
   union {
-    int iConstant;
-    float fConstant;
+    int iScalar;
+    float fScalar;
   };
 
 protected:
   ConstantValue(int value, const std::string &name = "")
-      : Value(Type::getIntType(), name), iConstant(value) {}
+      : Value(Type::getIntType(), name), iScalar(value) {}
   ConstantValue(float value, const std::string &name = "")
-      : Value(Type::getFloatType(), name), fConstant(value) {}
+      : Value(Type::getFloatType(), name), fScalar(value) {}
 
 public:
   static ConstantValue *get(int value, const std::string &name = "");
@@ -213,11 +218,11 @@ public:
 public:
   int getInt() const {
     assert(isInt());
-    return iConstant;
+    return iScalar;
   }
   float getFloat() const {
     assert(isFloat());
-    return fConstant;
+    return fScalar;
   }
 }; // class ConstantValue
 
@@ -584,10 +589,8 @@ class LoadInst : public Instruction {
 protected:
   LoadInst(Value *pointer, const std::vector<Value *> &indices = {},
            BasicBlock *parent = nullptr, const std::string &name = "")
-      : Instruction(
-            kLoad,
-            dynamic_cast<PointerType *>(pointer->getType())->getBaseType(),
-            parent, name) {
+      : Instruction(kLoad, pointer->getType()->as<PointerType>()->getBaseType(),
+                    parent, name) {
     addOperands(indices);
   }
 
@@ -644,10 +647,10 @@ protected:
 
 public:
   Type *getReturnType() const {
-    return dynamic_cast<FunctionType *>(getType())->getReturnType();
+    return getType()->as<FunctionType>()->getReturnType();
   }
   auto getParamTypes() const {
-    return dynamic_cast<FunctionType *>(getType())->getParamTypes();
+    return getType()->as<FunctionType>()->getParamTypes();
   }
   auto getBasicBlocks() { return make_range(blocks); }
   BasicBlock *getEntryBlock() { return blocks.front().get(); }
@@ -668,16 +671,21 @@ class GlobalValue : public User {
 
 protected:
   Module *parent;
+  bool hasInit;
 
 protected:
   GlobalValue(Module *parent, Type *type, const std::string &name,
-              const std::vector<Value *> &dims = {})
-      : User(type, name), parent(parent) {
+              const std::vector<Value *> &dims = {}, Value *init = nullptr)
+      : User(type, name), parent(parent), hasInit(init) {
+    assert(type->isPointer());
     addOperands(dims);
+    if (init)
+      addOperand(init);
   }
 
 public:
-  int getNumDims() const { return getNumOperands(); }
+  Value *init() const { return hasInit ? operands.back().getValue() : nullptr; }
+  int getNumDims() const { return getNumOperands() - (hasInit ? 1 : 0); }
   Value *getDim(int index) { return getOperand(index); }
 }; // class GlobalValue
 
diff --git a/src/SysYIRGenerator.cpp b/src/SysYIRGenerator.cpp
index 976c95f..b0a2cf3 100644
--- a/src/SysYIRGenerator.cpp
+++ b/src/SysYIRGenerator.cpp
@@ -10,10 +10,7 @@ any SysYIRGenerator::visitModule(SysYParser::ModuleContext *ctx) {
   auto pModule = new Module();
   assert(pModule);
   module.reset(pModule);
-  for (auto decl : ctx->decl())
-    visitDecl(decl);
-  for (auto func : ctx->func())
-    visitFunc(func);
+  visitChildren(ctx);
   return pModule;
 }