From 5e492f531bb4e55d60d1bfde948b7e01b609ece0 Mon Sep 17 00:00:00 2001
From: mxr <>
Date: Sat, 11 Apr 2026 01:08:07 +0800
Subject: [PATCH] =?UTF-8?q?feat(mir)=E5=A4=84=E7=90=86=E6=8C=87=E4=BB=A4?=
 =?UTF-8?q?=E7=AB=8B=E5=8D=B3=E6=95=B0=E8=B6=85=E5=87=BA=E8=8C=83=E5=9B=B4?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/mir/AsmPrinter.cpp | 88 ++++++++++++++++++++++++++++++++++++------
 1 file changed, 77 insertions(+), 11 deletions(-)

diff --git a/src/mir/AsmPrinter.cpp b/src/mir/AsmPrinter.cpp
index f30f6d7..aaf9825 100644
--- a/src/mir/AsmPrinter.cpp
+++ b/src/mir/AsmPrinter.cpp
@@ -102,6 +102,39 @@ void PrintOperand(std::ostream& os, const Operand& op) {
   }
 }
 
+// 判断立即数是否可作为 AArch64 ADD/SUB 指令的 12 位立即数（可左移 0 或 12 位）
+static bool IsLegalAddSubImm(int64_t imm) {
+  if (imm < 0) imm = -imm;  // 取绝对值，因为移位规则对称
+  if (imm <= 4095) return true;                 // 0-4095 直接合法
+  if ((imm & 0xFFF) == 0 && imm <= 4095 * 4096) return true; // 4096 的倍数且 ≤ 16773120
+  return false;
+}
+
+// 在匿名命名空间添加辅助函数
+static void PrintLoadImm64(std::ostream& os, PhysReg reg, uint64_t imm) {
+  // 输出 movz + movk 序列
+  uint16_t part0 = imm & 0xFFFF;
+  uint16_t part1 = (imm >> 16) & 0xFFFF;
+  uint16_t part2 = (imm >> 32) & 0xFFFF;
+  uint16_t part3 = (imm >> 48) & 0xFFFF;
+
+  os << "  movz " << PhysRegName(reg) << ", #" << part0;
+  if (part1 != 0 || part2 != 0 || part3 != 0) {
+    os << ", lsl #0";
+  }
+  os << "\n";
+
+  if (part1 != 0) {
+    os << "  movk " << PhysRegName(reg) << ", #" << part1 << ", lsl #16\n";
+  }
+  if (part2 != 0) {
+    os << "  movk " << PhysRegName(reg) << ", #" << part2 << ", lsl #32\n";
+  }
+  if (part3 != 0) {
+    os << "  movk " << PhysRegName(reg) << ", #" << part3 << ", lsl #48\n";
+  }
+}
+
 // 打印单条指令
 void PrintInstruction(std::ostream& os, const MachineInstr& instr,
                       const MachineFunction& function) {
@@ -112,15 +145,27 @@ void PrintInstruction(std::ostream& os, const MachineInstr& instr,
       os << "  stp x29, x30, [sp, #-16]!\n";
       os << "  mov x29, sp\n";
       if (function.GetFrameSize() > 0) {
-        os << "  sub sp, sp, #" << function.GetFrameSize() << "\n";
+        int64_t size = function.GetFrameSize();
+        if (IsLegalAddSubImm(size)) {
+          os << "  sub sp, sp, #" << size << "\n";
+        } else {
+          PrintLoadImm64(os, PhysReg::X16, size);
+          os << "  sub sp, sp, x16\n";
+        }
       }
       break;
     case Opcode::Epilogue:
-        if (function.GetFrameSize() > 0) {
-          os << "  add sp, sp, #" << function.GetFrameSize() << "\n";
+      if (function.GetFrameSize() > 0) {
+        int64_t size = function.GetFrameSize();
+        if (IsLegalAddSubImm(size)) {
+          os << "  add sp, sp, #" << size << "\n";
+        } else {
+          PrintLoadImm64(os, PhysReg::X16, size);
+          os << "  add sp, sp, x16\n";
         }
-        os << "  ldp x29, x30, [sp], #16\n";
-        break;
+      }
+      os << "  ldp x29, x30, [sp], #16\n";
+      break;
     case Opcode::MovImm:
       os << "  mov " << PhysRegName(ops.at(0).GetReg()) << ", #"
          << ops.at(1).GetImm() << "\n";
@@ -321,12 +366,33 @@ void PrintInstruction(std::ostream& os, const MachineInstr& instr,
          << ops.at(1).GetImm() << ", lsl #" << ops.at(2).GetImm() << "\n";
       break;
     case Opcode::LoadStackAddr: {
-      // 格式：add xd, sp, #offset
-      const FrameSlot& slot = GetFrameSlot(function, ops.at(1));
-      // 注意：FrameSlot.offset 是相对于栈底（函数入口 sp）的偏移，在 prologue 中 sp 已经下移
-      // 因此这里直接使用 slot.offset 即可
-      os << "  add " << PhysRegName(ops.at(0).GetReg()) << ", sp, #" << slot.offset << "\n";
-      break; 
+        const FrameSlot& slot = GetFrameSlot(function, ops.at(1));
+        int64_t offset = slot.offset;          // 偏移可能为正或负
+        PhysReg dst = ops.at(0).GetReg();
+
+        // 尝试生成简单的 add/sub 立即数指令
+        auto tryEmitSimple = [&]() -> bool {
+            if (offset >= 0 && offset <= 4095) {
+                os << "  add " << PhysRegName(dst) << ", sp, #" << offset << "\n";
+                return true;
+            } else if (offset < 0 && offset >= -4095) {
+                os << "  sub " << PhysRegName(dst) << ", sp, #" << (-offset) << "\n";
+                return true;
+            }
+            return false;
+        };
+
+        if (tryEmitSimple()) break;
+
+        // 复杂情况：偏移绝对值 > 4095，使用 x16 临时寄存器
+        uint64_t absOffset = (offset >= 0) ? offset : -offset;
+        PrintLoadImm64(os, PhysReg::X16, absOffset);
+        if (offset >= 0) {
+            os << "  add " << PhysRegName(dst) << ", sp, x16\n";
+        } else {
+            os << "  sub " << PhysRegName(dst) << ", sp, x16\n";
+        }
+        break;
     }
     default:
       os << "  // unknown instruction\n";