feat(mir)实现多条指令访问栈帧

src/mir/AsmPrinter.cpp

@@ -25,12 +25,59 @@ const FrameSlot& GetFrameSlot(const MachineFunction& function,
   return function.GetFrameSlot(operand.GetFrameIndex());
 }
 
-void PrintStackAccess(std::ostream& os, const char* mnemonic, PhysReg reg,
+/*void PrintStackAccess(std::ostream& os, const char* mnemonic, PhysReg reg,
                       int offset) {
-  //os << "  " << mnemonic << " " << PhysRegName(reg) << ", [x29, #" << offset
-  //   << "]\n";
   // 使用 sp 相对寻址
   os << "  " << mnemonic << " " << PhysRegName(reg) << ", [sp, #" << offset << "]\n";
+}*/
+
+void PrintStackAccess(std::ostream& os, const char* insn, PhysReg reg, int64_t offset) {
+  // 合法范围：-256 到 255
+  if (offset >= -256 && offset <= 255) {
+    os << "  " << insn << " " << PhysRegName(reg) << ", [sp, #" << offset << "]\n";
+    return;
+  }
+
+  // 大偏移：使用 x16 计算地址
+  os << "  mov x16, sp"<< "\n";
+
+  // 处理正偏移
+  if (offset >= 0) {
+    // AArch64 add immediate 范围 0~4095，超过则需要分解
+    if (offset <= 4095) {
+      os << "  add x16, x16, #" << offset << "\n";
+    } else {
+      // 简单分解：高部分必须是 4096 的倍数？这里为了通用，分两次加
+      // 更严谨的做法是循环，但栈帧一般不超过 8192，两次足够
+      int64_t low = offset & 0xFFF;        // 低12位
+      int64_t high = offset - low;
+      if (high > 0) {
+        os << "  add x16, x16, #" << high << "\n";
+      }
+      if (low > 0) {
+        os << "  add x16, x16, #" << low << "\n";
+      }
+    }
+  } 
+  // 处理负偏移
+  else {
+    int64_t abs_offset = -offset;
+    if (abs_offset <= 4095) {
+      os << "  sub x16, x16, #" << abs_offset << "\n";
+    } else {
+      int64_t low = abs_offset & 0xFFF;
+      int64_t high = abs_offset - low;
+      if (high > 0) {
+        os << "  sub x16, x16, #" << high << "\n";
+      }
+      if (low > 0) {
+        os << "  sub x16, x16, #" << low << "\n";
+      }
+    }
+  }
+
+  // 最后使用无偏移的 ldr/str（注意不是 ldur/stur）
+  os << "  " << insn << " " << PhysRegName(reg) << ", [x16]\n";
 }
 
 // 打印单个操作数

src/mir/FrameLowering.cpp

@@ -31,9 +31,9 @@ void RunFrameLowering(MachineFunction& function) {
     // 使用正偏移，从 sp 开始
     function.GetFrameSlot(slot.index).offset = cursor;
     cursor += slot.size;
-    if (-cursor < -256) {
+    /*if (-cursor < -256) {
       throw std::runtime_error(FormatError("mir", "暂不支持过大的栈帧"));
-    }
+    }*/
   }
   cursor = 0;
   for (const auto& slot : function.GetFrameSlots()) {