[IR]修复IR报错，调整结构。

src/IR.cpp

@@ -102,30 +102,54 @@ void Value::replaceAllUsesWith(Value *value) {
   uses.clear();
 }
 
-ConstantValue* ConstantValue::get(int value) {
-  static std::map<int, std::unique_ptr<ConstantValue>> intConstants;
-  auto iter = intConstants.find(value);
-  if (iter != intConstants.end()) {
-    return iter->second.get();
+
+// Implementations for static members
+
+std::unordered_map<ConstantValueKey, ConstantValue*, ConstantValueHash, ConstantValueEqual> ConstantValue::mConstantPool;
+std::unordered_map<Type*, UndefinedValue*> UndefinedValue::UndefValues;
+
+ConstantValue* ConstantValue::get(Type* type, ConstantValVariant val) {
+  ConstantValueKey key = {type, val};
+  auto it = mConstantPool.find(key);
+  if (it != mConstantPool.end()) {
+    return it->second;
   }
-  auto inst = new ConstantValue(value);
-  assert(inst);
-  auto result = intConstants.emplace(value, inst);
-  return result.first->second.get();
+
+  ConstantValue* newConstant = nullptr;
+  if (std::holds_alternative<int>(val)) {
+    newConstant = new ConstantInteger(type, std::get<int>(val));
+  } else if (std::holds_alternative<float>(val)) {
+    newConstant = new ConstantFloating(type, std::get<float>(val));
+  } else {
+    assert(false && "Unsupported ConstantValVariant type");
+  }
+
+  mConstantPool[key] = newConstant;
+  return newConstant;
 }
 
-ConstantValue* ConstantValue::get(float value) {
-  static std::map<float, std::unique_ptr<ConstantValue>> floatConstants;
-  auto iter = floatConstants.find(value);
-  if (iter != floatConstants.end()) {
-    return iter->second.get();
-  }
-  auto inst = new ConstantValue(value);
-  assert(inst);
-  auto result = floatConstants.emplace(value, inst);
-  return result.first->second.get();
+ConstantInteger* ConstantInteger::get(Type* type, int val) {
+  return dynamic_cast<ConstantInteger*>(ConstantValue::get(type, val));
 }
 
+ConstantFloating* ConstantFloating::get(Type* type, float val) {
+  return dynamic_cast<ConstantFloating*>(ConstantValue::get(type, val));
+}
+
+UndefinedValue* UndefinedValue::get(Type* type) {
+  assert(!type->isVoid() && "Cannot get UndefinedValue of void type!");
+
+  auto it = UndefValues.find(type);
+  if (it != UndefValues.end()) {
+    return it->second;
+  }
+
+  UndefinedValue* newUndef = new UndefinedValue(type);
+  UndefValues[type] = newUndef;
+  return newUndef;
+}
+
+
 auto Function::getCalleesWithNoExternalAndSelf() -> std::set<Function *> {
   std::set<Function *> result;
   for (auto callee : callees) {