From 49f91e3b4edb58e8ab8b1fe846126301704662bf Mon Sep 17 00:00:00 2001
From: Luke <luke.k.xu@hotmail.com>
Date: Tue, 17 Jun 2025 18:34:30 +0800
Subject: [PATCH] =?UTF-8?q?feat:=20=E5=A2=9E=E5=8A=A0=E6=8C=87=E4=BB=A4?=
 =?UTF-8?q?=E7=94=9F=E6=88=90=E5=99=A8=E9=9B=86=E4=B8=AD=E6=B3=A8=E5=86=8C?=
 =?UTF-8?q?=E8=A1=A8?=
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---
 .../InstructionGeneratorProvider.java         | 42 +++++++++++++++++++
 .../jcnc/snow/compiler/cli/SnowCompiler.java  | 26 +++++-------
 2 files changed, 52 insertions(+), 16 deletions(-)
 create mode 100644 src/main/java/org/jcnc/snow/compiler/backend/generator/InstructionGeneratorProvider.java

diff --git a/src/main/java/org/jcnc/snow/compiler/backend/generator/InstructionGeneratorProvider.java b/src/main/java/org/jcnc/snow/compiler/backend/generator/InstructionGeneratorProvider.java
new file mode 100644
index 0000000..2b2517d
--- /dev/null
+++ b/src/main/java/org/jcnc/snow/compiler/backend/generator/InstructionGeneratorProvider.java
@@ -0,0 +1,42 @@
+package org.jcnc.snow.compiler.backend.generator;
+
+import org.jcnc.snow.compiler.backend.core.InstructionGenerator;
+import org.jcnc.snow.compiler.ir.core.IRInstruction;
+
+import java.util.List;
+
+/**
+ * 指令生成器集中注册表。
+ *
+ * <p>本类在类加载阶段即完成所有后端 {@link InstructionGenerator} 实例
+ * 的创建，并以不可变列表形式对外暴露。
+ */
+public final class InstructionGeneratorProvider {
+
+    /** 工具类禁止实例化。 */
+    private InstructionGeneratorProvider() { /* no-instance */ }
+
+    /** 缺省指令生成器列表（不可修改，顺序即执行顺序）。 */
+    private static final List<InstructionGenerator<? extends IRInstruction>> DEFAULT =
+            List.of(
+                    new LoadConstGenerator(),  // 常量加载
+                    new BinaryOpGenerator(),   // 二元运算
+                    new UnaryOpGenerator(),    // 一元运算
+                    new CallGenerator(),       // 函数调用
+                    new ReturnGenerator(),     // 函数返回
+                    new LabelGenerator(),      // 标签定义
+                    new JumpGenerator(),       // 无条件跳转
+                    new CmpJumpGenerator()     // 条件跳转
+            );
+
+    /**
+     * 返回生产环境使用的缺省指令生成器列表。
+     * 该列表为不可变集合，如尝试修改将抛出
+     * {@link UnsupportedOperationException}。
+     *
+     * @return 不可变的 {@code List} 实例
+     */
+    public static List<InstructionGenerator<? extends IRInstruction>> defaultGenerators() {
+        return DEFAULT;
+    }
+}
diff --git a/src/main/java/org/jcnc/snow/compiler/cli/SnowCompiler.java b/src/main/java/org/jcnc/snow/compiler/cli/SnowCompiler.java
index fa0831a..512da03 100644
--- a/src/main/java/org/jcnc/snow/compiler/cli/SnowCompiler.java
+++ b/src/main/java/org/jcnc/snow/compiler/cli/SnowCompiler.java
@@ -4,11 +4,12 @@ import org.jcnc.snow.compiler.backend.alloc.RegisterAllocator;
 import org.jcnc.snow.compiler.backend.builder.VMCodeGenerator;
 import org.jcnc.snow.compiler.backend.builder.VMProgramBuilder;
 import org.jcnc.snow.compiler.backend.core.InstructionGenerator;
-import org.jcnc.snow.compiler.backend.generator.*;
+import org.jcnc.snow.compiler.backend.generator.InstructionGeneratorProvider;
 import org.jcnc.snow.compiler.ir.builder.IRProgramBuilder;
 import org.jcnc.snow.compiler.ir.core.IRFunction;
 import org.jcnc.snow.compiler.ir.core.IRInstruction;
 import org.jcnc.snow.compiler.ir.core.IRProgram;
+import org.jcnc.snow.compiler.ir.value.IRVirtualRegister;
 import org.jcnc.snow.compiler.lexer.core.LexerEngine;
 import org.jcnc.snow.compiler.parser.ast.base.Node;
 import org.jcnc.snow.compiler.parser.context.ParserContext;
@@ -20,7 +21,8 @@ import org.jcnc.snow.vm.engine.VirtualMachineEngine;
 
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
-import java.nio.file.*;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.util.*;
 
 /**
@@ -78,19 +80,10 @@ public class SnowCompiler {
 
         /* ---------- 5. IR → VM 指令 ---------- */
         VMProgramBuilder builder = new VMProgramBuilder();
-        List<InstructionGenerator<? extends IRInstruction>> generators = Arrays.asList(
-                new LoadConstGenerator(),
-                new BinaryOpGenerator(),
-                new UnaryOpGenerator(),
-                new CallGenerator(),
-                new ReturnGenerator(),
-                new LabelGenerator(),
-                new JumpGenerator(),
-                new CmpJumpGenerator()
-        );
+        List<InstructionGenerator<? extends IRInstruction>> generators = InstructionGeneratorProvider.defaultGenerators();
 
         for (IRFunction fn : program.functions()) {
-            Map<org.jcnc.snow.compiler.ir.value.IRVirtualRegister, Integer> slotMap =
+            Map<IRVirtualRegister, Integer> slotMap =
                     new RegisterAllocator().allocate(fn);
             new VMCodeGenerator(slotMap, builder, generators).generate(fn);
         }
@@ -108,8 +101,8 @@ public class SnowCompiler {
 
     /**
      * 根据参数收集待编译文件：
-     *   - snow file1 file2 …      ← 多文件 / 单文件
-     *   - snow -d srcDir          ← 目录递归所有 *.snow
+     * - snow file1 file2 …      ← 多文件 / 单文件
+     * - snow -d srcDir          ← 目录递归所有 *.snow
      */
     private static List<Path> collectSources(String[] args) throws IOException {
         if (args.length == 2 && "-d".equals(args[0])) {
@@ -137,7 +130,8 @@ public class SnowCompiler {
         int idx = -1;
         for (int i = 0; i < ordered.size(); i++) {
             if ("main".equals(ordered.get(i).name())) {
-                idx = i; break;
+                idx = i;
+                break;
             }
         }
         if (idx > 0) Collections.swap(ordered, 0, idx);