基本实现后端，生成的汇编代码可以得到能正确执行的程序。

src/backend/codegen.cpp

@@ -48,6 +48,7 @@ namespace backend
     {
         string code;
         code += space + ".global " + func->getName() + endl;
+        code += space + ".arm" + endl;
         code += space + ".p2align " + std::to_string(int_p2align) + endl;
         code += space + ".type " + func->getName() + ", %function" + endl;
         code += func->getName() + ":" + endl;
@@ -242,12 +243,12 @@ namespace backend
         string lname, rname;
         auto lhs = bInst->getLhs();
         if (isa<ConstantValue>(lhs))
-            lname = to_string(dynamic_cast<ConstantValue *>(lhs)->getInt());
+            lname = "#" + to_string(dynamic_cast<ConstantValue *>(lhs)->getInt());
         else
             lname = "r" + lhs->getName();
         auto rhs = bInst->getRhs();
         if (isa<ConstantValue>(rhs))
-            rname = to_string(dynamic_cast<ConstantValue *>(rhs)->getInt());
+            rname = "#" + to_string(dynamic_cast<ConstantValue *>(rhs)->getInt());
         else
             rname = "r" + rhs->getName();
         auto res = stoi(bInst->getName());
@@ -296,6 +297,10 @@ namespace backend
             code += space + "mov\tr3, #" + to_string(constant_value) + endl;
             code += space + "str\tr3, [fp, #" + to_string(offset) + "]" + endl;
         }
+        else if (isa<CallInst>(value))
+        {
+            code += space + "str\tr0, [fp, #" + to_string(offset) + "]" + endl;
+        }
         else
         {
             code += space + "str\tr" + value->getName() + ", [fp, #" + to_string(offset) + "]" + endl;

src/backend/codegen.hpp

@@ -55,7 +55,7 @@ using std::vector;
 
 namespace backend
 {
-    static const string space = string(4, ' ');
+    static const string space = "\t";
     static const string endl = "\n";
     // only for armv7
     static const int int_align = 4;