refactor(php): 优化PHP编译器基础组件结构

- 在CompilerBase中添加类继承关系存储数组并增加注释说明
- 重命名FileSorter中的变量名提高代码可读性
- 简化Preprocessor中局部变量声明方式
- 限定prepareFunction方法参数类型增强类型安全
- 添加关于父类方法覆盖的注释说明

src/Php/CompilerBase.php

@@ -245,6 +245,10 @@ class CompilerBase extends \PhpAot\Core\Translator
      * @var array<string, bool>
      */
     protected array $classMethodOverride = [];
+    /**
+     * 存储所有类继承关系，类名必须全部为小写
+     * @var array<string, string>
+     */
     protected array $classExtends = [];
 
     public function __construct(string $rootPath)

src/Php/FileSorter.php

@@ -66,11 +66,11 @@ class FileSorter
         $dependencies = [];
 
         foreach ($this->symbolCallInFile as $call) {
-            $callerFile   = $call['file'];
-            $functionName = $call['name'];
+            $callerFile = $call['file'];
+            $symbolName = $call['name'];
 
-            if (isset($this->symbolDeclInFile[$functionName])) {
-                $declFile = $this->symbolDeclInFile[$functionName];
+            if (isset($this->symbolDeclInFile[$symbolName])) {
+                $declFile = $this->symbolDeclInFile[$symbolName];
 
                 if ($callerFile !== $declFile) {
                     if (!isset($dependencies[$callerFile])) {

src/Php/Preprocessor.php

@@ -115,7 +115,7 @@ class Preprocessor extends CompilerBase
             }
         }
 
-        $nodeFinder    = new NodeFinder();
+        $nodeFinder = new NodeFinder();
         $functionCalls = $nodeFinder->findInstanceOf($ast, Node\Expr\FuncCall::class);
 
         foreach ($functionCalls as $call) {
@@ -158,7 +158,7 @@ class Preprocessor extends CompilerBase
         $this->resetNamespace();
     }
 
-    protected function prepareFunction(Node $v): void
+    protected function prepareFunction(Node\Stmt\ClassMethod|Node\Stmt\Function_ $v): void
     {
         $name = $this->getFunctionName($v);
         if ($this->stubFile) {
@@ -232,6 +232,7 @@ class Preprocessor extends CompilerBase
             while (isset($this->classExtends[$fullClassNameLower])) {
                 $parentClass = $this->classExtends[$fullClassNameLower];
                 $parentMethodLower = strtolower($parentClass . '::' . $v->name);
+                // 父类有同名方法，子类覆盖了父类方法，这种情况不能直接使用 C++ 函数，而是使用 ZendVM 动态调用
                 if (isset($this->classMethodOverride[$parentMethodLower])) {
                     $this->classMethodOverride[$parentMethodLower] = true;
                 }