diff --git a/examples/micro_bench.php b/examples/micro_bench.php
index be713990..b20d0d53 100644
--- a/examples/micro_bench.php
+++ b/examples/micro_bench.php
@@ -18,7 +18,7 @@ function hallo2() {
 
 function simpleicall($n) {
   for ($i = 0; $i < $n; $i++)
-    function_exists('hallo');
+    $ret = function_exists('hallo');
 }
 
 class Foo {
@@ -287,74 +287,74 @@ function main()
     empty_loop(N);
     $t = end_test($t, 'empty_loop');
     $overhead = $last_time;
-    simpleucall(N);
-    $t = end_test($t, 'func()', $overhead);
-    simpleudcall(N);
-    $t = end_test($t, 'undef_func()', $overhead);
+//    simpleucall(N);
+//    $t = end_test($t, 'func()', $overhead);
+//    simpleudcall(N);
+//    $t = end_test($t, 'undef_func()', $overhead);
     simpleicall(N);
     $t = end_test($t, 'int_func()', $overhead);
-    Foo::read_static(N);
-    $t = end_test($t, '$x = self::$x', $overhead);
-    Foo::write_static(N);
-    $t = end_test($t, 'self::$x = 0', $overhead);
-    Foo::isset_static(N);
-    $t = end_test($t, 'isset(self::$x)', $overhead);
-    Foo::empty_static(N);
-    $t = end_test($t, 'empty(self::$x)', $overhead);
-    read_static(N);
-    $t = end_test($t, '$x = Foo::$x', $overhead);
-    write_static(N);
-    $t = end_test($t, 'Foo::$x = 0', $overhead);
-    isset_static(N);
-    $t = end_test($t, 'isset(Foo::$x)', $overhead);
-    empty_static(N);
-    $t = end_test($t, 'empty(Foo::$x)', $overhead);
-    Foo::call_static(N);
-    $t = end_test($t, 'self::f()', $overhead);
-    call_static(N);
-    $t = end_test($t, 'Foo::f()', $overhead);
-    $x = new Foo();
-    $x->read_prop(N);
-    $t = end_test($t, '$x = $this->x', $overhead);
-    $x->write_prop(N);
-    $t = end_test($t, '$this->x = 0', $overhead);
-    $x->assign_add_prop(N);
-    $t = end_test($t, '$this->x += 2', $overhead);
-    $x->pre_inc_prop(N);
-    $t = end_test($t, '++$this->x', $overhead);
-    $x->pre_dec_prop(N);
-    $t = end_test($t, '--$this->x', $overhead);
-    $x->post_inc_prop(N);
-    $t = end_test($t, '$this->x++', $overhead);
-    $x->post_dec_prop(N);
-    $t = end_test($t, '$this->x--', $overhead);
-    $x->isset_prop(N);
-    $t = end_test($t, 'isset($this->x)', $overhead);
-    $x->empty_prop(N);
-    $t = end_test($t, 'empty($this->x)', $overhead);
-    $x->call(N);
-    $t = end_test($t, '$this->f()', $overhead);
-    $x->read_const(N);
-    $t = end_test($t, '$x = Foo::TEST', $overhead);
-    create_object(N);
-    $t = end_test($t, 'new Foo()', $overhead);
-    read_const(N);
-    $t = end_test($t, '$x = TEST', $overhead);
-    read_auto_global(N);
-    $t = end_test($t, '$x = $_GET', $overhead);
-    read_global_var(N);
-    $t = end_test($t, '$x = $GLOBALS[\'v\']', $overhead);
-    read_hash(N);
-    $t = end_test($t, '$x = $hash[\'v\']', $overhead);
-    read_str_offset(N);
-    $t = end_test($t, '$x = $str[0]', $overhead);
-    issetor(N);
-    $t = end_test($t, '$x = $a ?: null', $overhead);
-    issetor2(N);
-    $t = end_test($t, '$x = $f ?: tmp', $overhead);
-    ternary(N);
-    $t = end_test($t, '$x = $f ? $f : $a', $overhead);
-    ternary2(N);
-    $t = end_test($t, '$x = $f ? $f : tmp', $overhead);
+//    Foo::read_static(N);
+//    $t = end_test($t, '$x = self::$x', $overhead);
+//    Foo::write_static(N);
+//    $t = end_test($t, 'self::$x = 0', $overhead);
+//    Foo::isset_static(N);
+//    $t = end_test($t, 'isset(self::$x)', $overhead);
+//    Foo::empty_static(N);
+//    $t = end_test($t, 'empty(self::$x)', $overhead);
+//    read_static(N);
+//    $t = end_test($t, '$x = Foo::$x', $overhead);
+//    write_static(N);
+//    $t = end_test($t, 'Foo::$x = 0', $overhead);
+//    isset_static(N);
+//    $t = end_test($t, 'isset(Foo::$x)', $overhead);
+//    empty_static(N);
+//    $t = end_test($t, 'empty(Foo::$x)', $overhead);
+//    Foo::call_static(N);
+//    $t = end_test($t, 'self::f()', $overhead);
+//    call_static(N);
+//    $t = end_test($t, 'Foo::f()', $overhead);
+//    $x = new Foo();
+//    $x->read_prop(N);
+//    $t = end_test($t, '$x = $this->x', $overhead);
+//    $x->write_prop(N);
+//    $t = end_test($t, '$this->x = 0', $overhead);
+//    $x->assign_add_prop(N);
+//    $t = end_test($t, '$this->x += 2', $overhead);
+//    $x->pre_inc_prop(N);
+//    $t = end_test($t, '++$this->x', $overhead);
+//    $x->pre_dec_prop(N);
+//    $t = end_test($t, '--$this->x', $overhead);
+//    $x->post_inc_prop(N);
+//    $t = end_test($t, '$this->x++', $overhead);
+//    $x->post_dec_prop(N);
+//    $t = end_test($t, '$this->x--', $overhead);
+//    $x->isset_prop(N);
+//    $t = end_test($t, 'isset($this->x)', $overhead);
+//    $x->empty_prop(N);
+//    $t = end_test($t, 'empty($this->x)', $overhead);
+//    $x->call(N);
+//    $t = end_test($t, '$this->f()', $overhead);
+//    $x->read_const(N);
+//    $t = end_test($t, '$x = Foo::TEST', $overhead);
+//    create_object(N);
+//    $t = end_test($t, 'new Foo()', $overhead);
+//    read_const(N);
+//    $t = end_test($t, '$x = TEST', $overhead);
+//    read_auto_global(N);
+//    $t = end_test($t, '$x = $_GET', $overhead);
+//    read_global_var(N);
+//    $t = end_test($t, '$x = $GLOBALS[\'v\']', $overhead);
+//    read_hash(N);
+//    $t = end_test($t, '$x = $hash[\'v\']', $overhead);
+//    read_str_offset(N);
+//    $t = end_test($t, '$x = $str[0]', $overhead);
+//    issetor(N);
+//    $t = end_test($t, '$x = $a ?: null', $overhead);
+//    issetor2(N);
+//    $t = end_test($t, '$x = $f ?: tmp', $overhead);
+//    ternary(N);
+//    $t = end_test($t, '$x = $f ? $f : $a', $overhead);
+//    ternary2(N);
+//    $t = end_test($t, '$x = $f ? $f : tmp', $overhead);
     total();
 }
diff --git a/src/Php/CompilerBase.php b/src/Php/CompilerBase.php
index 0b03f07b..d17b0ced 100644
--- a/src/Php/CompilerBase.php
+++ b/src/Php/CompilerBase.php
@@ -607,11 +607,11 @@ class CompilerBase extends \PhpAot\Core\Translator
         if (isset($this->classMap[$className])) {
             $id = $this->classMap[$className];
         } else {
-            $id                         = $this->classIndex++;
+            $id = $this->classIndex++;
             $this->classMap[$className] = $id;
         }
 
-        return 'php_get_class(' . $id . ', "' . $this->escapeString($className) . '")';
+        return 'php_get_class(' . $id . ', ' . $this->getLiteralString($className) . ')';
     }
 
     protected function getFuncPtr(string $funcName): string
@@ -622,7 +622,7 @@ class CompilerBase extends \PhpAot\Core\Translator
             $id = $this->funcIndex++;
             $this->funcMap[$funcName] = $id;
         }
-        return $id . ', "' . $this->escapeString($funcName) . '"';
+        return $id . ', ' . $this->getLiteralString($funcName);
     }
 
     protected function parseFunctionDeclaration(Node\Stmt\Function_|Node\Stmt\ClassMethod $v): FunctionDef
@@ -712,7 +712,16 @@ class CompilerBase extends \PhpAot\Core\Translator
         }
     }
 
-    protected function parseScalar(Node $expr)
+    protected function getLiteralString(string $string): string
+    {
+        if ($this->noLiteralStrings) {
+            return '"' . $this->escapeString($string) . '"';
+        }
+        $index = $this->literalStrings[$string] ?? $this->addLiteralString($string);
+        return self::LITERAL_STRINGS . '[' . $index . ']';
+    }
+
+    protected function parseScalar(Node\Scalar $expr)
     {
         $type = $expr->getType();
         switch ($type) {
@@ -721,13 +730,7 @@ class CompilerBase extends \PhpAot\Core\Translator
             case 'Scalar_Float':
                 return $this->parseScalarFloat($expr);
             case 'Scalar_String':
-                if ($this->noLiteralStrings) {
-                    return '"' . $this->escapeString($expr->value) . '"';
-                }
-                $index = $this->literalStrings[$expr->value] ?? $this->addLiteralString($expr->value);
-
-                return self::LITERAL_STRINGS . '[' . $index . ']';
-
+                return $this->getLiteralString($expr->value);
             default:
                 abort($expr);
         }
diff --git a/src/Php/FuncCallOptimizer.php b/src/Php/FuncCallOptimizer.php
index e9c3cf3c..f1f95807 100644
--- a/src/Php/FuncCallOptimizer.php
+++ b/src/Php/FuncCallOptimizer.php
@@ -44,6 +44,9 @@ trait FuncCallOptimizer
         if ($name === 'abs') {
             return 'php::math::abs(' . $this->parseIdentifier($expr->args[0]->value) . ')';
         }
+        if ($name === 'function_exists') {
+            return 'php::fn::function_exists(' . $this->parseIdentifier($expr->args[0]->value) . ')';
+        }
 
         return false;
     }
diff --git a/src/Php/Translator.php b/src/Php/Translator.php
index 7b553775..e2a64956 100644
--- a/src/Php/Translator.php
+++ b/src/Php/Translator.php
@@ -197,7 +197,7 @@ class Translator extends Preprocessor
         }
 
         $literalStringsCount = count($this->literalStrings);
-        $lines[]             = 'extern php::Var ' . self::LITERAL_STRINGS . '[' . $literalStringsCount . '];' . PHP_EOL;
+        $lines[] = 'extern ' . self::TYPE_STR . ' ' . self::LITERAL_STRINGS . '[' . $literalStringsCount . '];' . PHP_EOL;
 
         $classCount = count($this->classMap);
         $lines[]         = 'extern zend_class_entry *' . self::PREFIX . self::CLASS_MAP . '[' . $classCount . '];' . PHP_EOL;
diff --git a/src/cpp/php_aot_helper.h b/src/cpp/php_aot_helper.h
index 76136713..2a38e580 100644
--- a/src/cpp/php_aot_helper.h
+++ b/src/cpp/php_aot_helper.h
@@ -1,20 +1,20 @@
 #include <phpx.h>
 
-extern zend_class_entry *php_get_class(int class_id, const char *class_name);
-extern zend_function *php_get_func(int func_id, const char *func_name);
+extern zend_class_entry *php_get_class(int class_id, const php::String &class_name);
+extern zend_function *php_get_func(int func_id, const php::String &func_name);
 
-static inline php::Variant CALL(int func_id, const char *func_name, const std::initializer_list<php::Variant> &args) {
+static inline php::Variant CALL(int func_id, const php::String &func_name, const std::initializer_list<php::Variant> &args) {
     return php::call(php_get_func(func_id, func_name), args);
 }
 
-static inline php::Variant CALL(int func_id, const char *func_name) {
+static inline php::Variant CALL(int func_id, const php::String &func_name) {
     return php::call(php_get_func(func_id, func_name));
 }
 
-static inline php::Variant CALL_SILENT(int func_id, const char *func_name, const std::initializer_list<php::Variant> &args) {
+static inline php::Variant CALL_SILENT(int func_id, const php::String &func_name, const std::initializer_list<php::Variant> &args) {
     return php::silentCall(php_get_func(func_id, func_name), args);
 }
 
-static inline php::Variant CALL_SILENT(int func_id, const char *func_name) {
+static inline php::Variant CALL_SILENT(int func_id, const php::String &func_name) {
     return php::silentCall(php_get_func(func_id, func_name));
 }
diff --git a/src/template/extension.cc.php b/src/template/extension.cc.php
index 43750218..5f3d0a7e 100644
--- a/src/template/extension.cc.php
+++ b/src/template/extension.cc.php
@@ -27,14 +27,14 @@ zend_class_entry *<?= Translator::PREFIX . Translator::CLASS_MAP . '[' . count($
 // func
 zend_function *<?= Translator::PREFIX . Translator::FUNC_MAP . '[' . count($this->funcMap) . ']' ?>;
 
-zend_class_entry *php_get_class(int class_id, const char *class_name) {
+zend_class_entry *php_get_class(int class_id, const php::String &class_name) {
     if (UNEXPECTED(<?= Translator::PREFIX . Translator::CLASS_MAP ?>[class_id] == nullptr)) {
         <?= Translator::PREFIX . Translator::CLASS_MAP ?>[class_id] = php::getClassEntrySafe(class_name);
     }
     return <?= Translator::PREFIX . Translator::CLASS_MAP ?>[class_id];
 }
 
-zend_function *php_get_func(int func_id, const char *func_name) {
+zend_function *php_get_func(int func_id, const php::String &func_name) {
     if (UNEXPECTED(<?= Translator::PREFIX . Translator::FUNC_MAP ?>[func_id] == nullptr)) {
         <?= Translator::PREFIX . Translator::FUNC_MAP ?>[func_id] = php::getFunction(func_name);
     }
@@ -42,7 +42,7 @@ zend_function *php_get_func(int func_id, const char *func_name) {
 }
 
 // literal strings
-php::Var <?=Translator::LITERAL_STRINGS?>[] = {
+php::Str <?=Translator::LITERAL_STRINGS?>[] = {
 <?php
 foreach ($this->literalStrings as $str => $index):
 ?>