fix(aot): 修复空合并运算符的编译逻辑

- 在 parseExpr 中添加对 replace 属性的检查
- 修改 coalesce 运算符的处理逻辑，避免重复函数调用
- 添加临时变量来存储 coalesce 表达式的结果
- 更新测试用例以验证正确的执行顺序和结果
- 添加新的测试用例验证 null 合并运算符行为
- 添加测试用例验证 ??= 运算符的链式赋值功能

src/Php/CompilerBase.php

@@ -310,6 +310,9 @@ class CompilerBase extends \PhpAot\Core\Translator
 
     public function parseExpr(NodeAbstract $expr)
     {
+        if ($expr->hasAttribute('replace')) {
+            return $expr->getAttribute('replace');
+        }
         $type = $expr->getType();
         $this->writeLog('Line ' . $this->getLine($expr) . ': ' . $type);
         if ($expr->getLine() === $this->debugLine) {
@@ -2924,17 +2927,21 @@ class CompilerBase extends \PhpAot\Core\Translator
             $this->checkVarMustExist($expr->left, $left);
         }
 
-        $this->mustNoCall($expr->right);
-        $right = $this->parseIdentifier($expr->right);
-        $this->checkVarMustExist($expr->right, $right);
-
         $isset = $this->parseChainedExpr($expr->left, self::OP_ISSET, true);
         $chainOpResult = $expr->left->getAttribute('chainOpResult');
         if ($chainOpResult) {
             $left = $chainOpResult;
         }
 
-        return $isset . ' ? ' . $left . ' : ' . $right;
+        $right = $this->parseIdentifier($expr->right);
+        $this->checkVarMustExist($expr->right, $right);
+
+        $tmpVar = $this->addTmpVar(self::TYPE_VAR);
+        $this->context->beforeStmtLines[] = '// Coalesce: ' . $this->printer->prettyPrintExpr($expr) . PHP_EOL .
+            $tmpVar . ' = ' . $isset . ' ? ' . $left . ' : ' . $right . ';';
+        $expr->setAttribute('replace', $tmpVar);
+
+        return $tmpVar;
     }
 
     protected function parseBinaryOpNotIdentical(Node\Expr\BinaryOp $expr): string

tests/aot/coalesce/002.phpt

@@ -10,14 +10,16 @@ function f($x)
 }
 
 function main() {
-    $r1 = f(1);
-    $r2 = f(2);
-    $a = f(null) ?? $r1 ?? $r2;
+    $a = f(null) ?? f(2);
+    var_dump($a);
+
+    $a = f(1) ?? f(2);
     var_dump($a);
 }
 ?>
---EXPECTF--
-f(1)
-f(2)
+--EXPECT--
 f(0)
-int(1)
+f(2)
+int(2)
+f(1)
+int(1)

tests/aot/coalesce/003.phpt

@@ -0,0 +1,20 @@
+--TEST--
+Test ?? operator
+--FILE--
+<?php
+
+function f($x)
+{
+    printf("%s(%d)\n", __FUNCTION__, $x);
+    return $x;
+}
+
+function main() {
+    $a = f(null) ?? f(1) ?? f(2);
+    var_dump($a);
+}
+?>
+--EXPECT--
+f(0)
+f(1)
+int(1)

tests/aot/coalesce/004.phpt

@@ -0,0 +1,28 @@
+--TEST--
+Test ?? operator
+--FILE--
+<?php
+function foo1() {
+    $c = 100;
+    $a ??=  $b ??= $c;
+    var_dump($a, $b);
+
+}
+
+function foo2() {
+    $c = 100;
+    $b = 33;
+    $a ??=  $b ??= $c;
+    var_dump($a, $b);
+}
+
+function main() {
+    foo1();
+    foo2();
+}
+?>
+--EXPECT--
+int(100)
+int(100)
+int(33)
+int(33)