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php 对象的执行

發布時間：2023/11/27 生活经验 22 豆豆

生活随笔收集整理的這篇文章主要介紹了 php 对象的执行小編覺得挺不錯的,現在分享給大家,幫大家做個參考.

1.BNF范式

%token T_OBJECT_OPERATOR "-> (T_OBJECT_OPERATOR)"

unticked_statement:
|    expr ';'                { zend_do_free(&$1 TSRMLS_CC); }expr:r_variable                    { $$ = $1; }|    expr_without_variable        { $$ = $1; }
;r_variable:variable { zend_do_end_variable_parse(&$1, BP_VAR_R, 0 TSRMLS_CC); $$ = $1; }
;

//object_property可能是成員變量，可能是成員函數,可產生$obj->xx->xx()的形式
variable:base_variable_with_function_calls T_OBJECT_OPERATOR { zend_do_push_object(&$1 TSRMLS_CC); }object_property { zend_do_push_object(&$4 TSRMLS_CC); } method_or_not variable_properties{ zend_do_pop_object(&$$ TSRMLS_CC); $$.EA = $1.EA | ($7.EA ? $7.EA : $6.EA); }|    base_variable_with_function_calls { $$ = $1; }
;

　　base_variable_with_function_calls:
　　　　base_variable { $$ = $1; }
　　;

　　base_variable:
　　　　reference_variable { $$ = $1; $$.EA = ZEND_PARSED_VARIABLE; }
　　;

　reference_variable:|    compound_variable            { zend_do_begin_variable_parse(TSRMLS_C); fetch_simple_variable(&$$, &$1, 1 TSRMLS_CC); };compound_variable:T_VARIABLE            { $$ = $1; }|    '$' '{' expr '}'    { $$ = $3; }
;

object_property: 
　　object_dim_list { $$ = $1; } 
;

? object_dim_list:

　　 ?variable_name { znode tmp_znode; zend_do_pop_object(&tmp_znode TSRMLS_CC); zend_do_fetch_property(&$$, &tmp_znode, &$1 TSRMLS_CC);}
? ;

? variable_name:
　　T_STRING { $$ = $1; }
? ;

　variable_properties:
　　　variable_properties variable_property { $$.EA = $2.EA; }
　　　| /* empty */ { $$.EA = 0; }
　　　;

　variable_property:
　　　　T_OBJECT_OPERATOR object_property { zend_do_push_object(&$2 TSRMLS_CC); } method_or_not { $$.EA = $4.EA; }
　　;


method_or_not:method                        { $$ = $1; $$.EA = ZEND_PARSED_METHOD_CALL; zend_do_push_object(&$$ TSRMLS_CC); }|    array_method_dereference    { $$ = $1; zend_do_push_object(&$$ TSRMLS_CC); }|    /* empty */ { $$.EA = ZEND_PARSED_MEMBER; }
;method:'(' { zend_do_pop_object(&$1 TSRMLS_CC); zend_do_begin_method_call(&$1 TSRMLS_CC); }function_call_parameter_list ')'{ zend_do_end_function_call(&$1, &$$, &$3, 1, 1 TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C); }
;

1對于$this->abc中的$this

void fetch_simple_variable_ex(znode *result, znode *varname, int bp, zend_uchar op TSRMLS_DC) /* {{{ */
{zend_op opline;zend_op *opline_ptr;zend_llist *fetch_list_ptr;if (varname->op_type == IS_CONST) {ulong hash;//如果不是以$this開頭的變量，根據lookup_cv函數，在active_syymble_table變量中增加一個keyhash = str_hash(Z_STRVAL(varname->u.constant), Z_STRLEN(varname->u.constant));if (!zend_is_auto_global_quick(Z_STRVAL(varname->u.constant), Z_STRLEN(varname->u.constant), hash TSRMLS_CC) &&!(Z_STRLEN(varname->u.constant) == (sizeof("this")-1) &&!memcmp(Z_STRVAL(varname->u.constant), "this", sizeof("this") - 1)) &&(CG(active_op_array)->last == 0 ||CG(active_op_array)->opcodes[CG(active_op_array)->last-1].opcode != ZEND_BEGIN_SILENCE)) {result->op_type = IS_CV;result->u.op.var = lookup_cv(CG(active_op_array), Z_STRVAL(varname->u.constant), Z_STRLEN(varname->u.constant), hash TSRMLS_CC);Z_STRVAL(varname->u.constant) = (char*)CG(active_op_array)->vars[result->u.op.var].name;result->EA = 0;return;}}if (bp) {opline_ptr = &opline;init_op(opline_ptr TSRMLS_CC);} else {opline_ptr = get_next_op(CG(active_op_array) TSRMLS_CC);}opline_ptr->opcode = op;opline_ptr->result_type = IS_VAR;opline_ptr->result.var = get_temporary_variable(CG(active_op_array));SET_NODE(opline_ptr->op1, varname);GET_NODE(result, opline_ptr->result);SET_UNUSED(opline_ptr->op2);opline_ptr->extended_value = ZEND_FETCH_LOCAL;if (varname->op_type == IS_CONST) {CALCULATE_LITERAL_HASH(opline_ptr->op1.constant);if (zend_is_auto_global_quick(Z_STRVAL(varname->u.constant), Z_STRLEN(varname->u.constant), Z_HASH_P(&CONSTANT(opline_ptr->op1.constant)) TSRMLS_CC)) {opline_ptr->extended_value = ZEND_FETCH_GLOBAL;}}if (bp) {zend_stack_top(&CG(bp_stack), (void **) &fetch_list_ptr);zend_llist_add_element(fetch_list_ptr, opline_ptr);}
}
/* }}} */void fetch_simple_variable(znode *result, znode *varname, int bp TSRMLS_DC) /* {{{ */
{/* the default mode must be Write, since fetch_simple_variable() is used to define function arguments */fetch_simple_variable_ex(result, varname, bp, ZEND_FETCH_W TSRMLS_CC);
}

?zend_do_fetch_property

void zend_do_fetch_property(znode *result, znode *object, const znode *property TSRMLS_DC) /* {{{ */
{zend_op opline;zend_llist *fetch_list_ptr;zend_stack_top(&CG(bp_stack), (void **) &fetch_list_ptr);if (object->op_type == IS_CV) {if (object->u.op.var == CG(active_op_array)->this_var) {object->op_type = IS_UNUSED; /* this means $this for objects */}} else if (fetch_list_ptr->count == 1) {//針對于$abc=1;或$this->abc=1;的這種情況//對$abc或$this已經進行了fetch_simple_variable函數處理了zend_llist_element *le = fetch_list_ptr->head;zend_op *opline_ptr = (zend_op *) le->data;if (opline_is_fetch_this(opline_ptr TSRMLS_CC)) {zend_del_literal(CG(active_op_array), opline_ptr->op1.constant);SET_UNUSED(opline_ptr->op1); /* this means $this for objects */SET_NODE(opline_ptr->op2, property);/* if it was usual fetch, we change it to object fetch */switch (opline_ptr->opcode) {case ZEND_FETCH_W:opline_ptr->opcode = ZEND_FETCH_OBJ_W;break;case ZEND_FETCH_R:opline_ptr->opcode = ZEND_FETCH_OBJ_R;break;}if (opline_ptr->op2_type == IS_CONST && Z_TYPE(CONSTANT(opline_ptr->op2.constant)) == IS_STRING) {CALCULATE_LITERAL_HASH(opline_ptr->op2.constant);GET_POLYMORPHIC_CACHE_SLOT(opline_ptr->op2.constant);}GET_NODE(result, opline_ptr->result);return;}}if (zend_is_function_or_method_call(object)) {init_op(&opline TSRMLS_CC);opline.opcode = ZEND_SEPARATE;SET_NODE(opline.op1, object);SET_UNUSED(opline.op2);opline.result_type = IS_VAR;opline.result.var = opline.op1.var;zend_llist_add_element(fetch_list_ptr, &opline);}init_op(&opline TSRMLS_CC);opline.opcode = ZEND_FETCH_OBJ_W;    /* the backpatching routine assumes W */opline.result_type = IS_VAR;opline.result.var = get_temporary_variable(CG(active_op_array));SET_NODE(opline.op1, object);SET_NODE(opline.op2, property);if (opline.op2_type == IS_CONST && Z_TYPE(CONSTANT(opline.op2.constant)) == IS_STRING) {CALCULATE_LITERAL_HASH(opline.op2.constant);GET_POLYMORPHIC_CACHE_SLOT(opline.op2.constant);}GET_NODE(result, opline.result);zend_llist_add_element(fetch_list_ptr, &opline);
}

2函數 zend_do_begin_method_call

void zend_do_begin_method_call(znode *left_bracket TSRMLS_DC) /* {{{ */
{zend_op *last_op;int last_op_number;unsigned char *ptr = NULL;//代碼省略last_op_number = get_next_op_number(CG(active_op_array))-1; //$obj->func()last_op = &CG(active_op_array)->opcodes[last_op_number];//代碼省略if (last_op->opcode == ZEND_FETCH_OBJ_R) {if (last_op->op2_type == IS_CONST) {zval name;name = CONSTANT(last_op->op2.constant);if (Z_TYPE(name) != IS_STRING) {zend_error(E_COMPILE_ERROR, "Method name must be a string");} if (!IS_INTERNED(Z_STRVAL(name))) {Z_STRVAL(name) = estrndup(Z_STRVAL(name), Z_STRLEN(name));}FREE_POLYMORPHIC_CACHE_SLOT(last_op->op2.constant);last_op->op2.constant =zend_add_func_name_literal(CG(active_op_array), &name TSRMLS_CC);GET_POLYMORPHIC_CACHE_SLOT(last_op->op2.constant);}last_op->opcode = ZEND_INIT_METHOD_CALL;SET_UNUSED(last_op->result);Z_LVAL(left_bracket->u.constant) = ZEND_INIT_FCALL_BY_NAME;} else {}    
}

ZEND_INIT_METHOD_CALL 取出函數體EX(fbc)?

static int ZEND_FASTCALL  ZEND_INIT_METHOD_CALL_SPEC_CV_CONST_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
{USE_OPLINEzval *function_name;char *function_name_strval;int function_name_strlen;SAVE_OPLINE();zend_ptr_stack_3_push(&EG(arg_types_stack), EX(fbc), EX(object), EX(called_scope));function_name = opline->op2.zv;if (IS_CONST != IS_CONST &&UNEXPECTED(Z_TYPE_P(function_name) != IS_STRING)) {zend_error_noreturn(E_ERROR, "Method name must be a string");}function_name_strval = Z_STRVAL_P(function_name);function_name_strlen = Z_STRLEN_P(function_name);EX(object) = _get_zval_ptr_cv_BP_VAR_R(EX_CVs(), opline->op1.var TSRMLS_CC);if (EXPECTED(EX(object) != NULL) &&EXPECTED(Z_TYPE_P(EX(object)) == IS_OBJECT)) {EX(called_scope) = Z_OBJCE_P(EX(object));if (IS_CONST != IS_CONST ||(EX(fbc) = CACHED_POLYMORPHIC_PTR(opline->op2.literal->cache_slot, EX(called_scope))) == NULL) {zval *object = EX(object);if (UNEXPECTED(Z_OBJ_HT_P(EX(object))->get_method == NULL)) {zend_error_noreturn(E_ERROR, "Object does not support method calls");}/* First, locate the function. */

            //獲取所調用方法的 fbcEX(fbc) = Z_OBJ_HT_P(EX(object))->get_method(&EX(object), function_name_strval, function_name_strlen, ((IS_CONST == IS_CONST) ? (opline->op2.literal + 1) : NULL) TSRMLS_CC);if (UNEXPECTED(EX(fbc) == NULL)) {zend_error_noreturn(E_ERROR, "Call to undefined method %s::%s()", Z_OBJ_CLASS_NAME_P(EX(object)), function_name_strval);}if (IS_CONST == IS_CONST &&EXPECTED(EX(fbc)->type <= ZEND_USER_FUNCTION) &&EXPECTED((EX(fbc)->common.fn_flags & (ZEND_ACC_CALL_VIA_HANDLER|ZEND_ACC_NEVER_CACHE)) == 0) &&EXPECTED(EX(object) == object)) {CACHE_POLYMORPHIC_PTR(opline->op2.literal->cache_slot, EX(called_scope), EX(fbc));}}} else {zend_error_noreturn(E_ERROR, "Call to a member function %s() on a non-object", function_name_strval);}if ((EX(fbc)->common.fn_flags & ZEND_ACC_STATIC) != 0) {EX(object) = NULL;} else {if (!PZVAL_IS_REF(EX(object))) {Z_ADDREF_P(EX(object)); /* For $this pointer */} else {zval *this_ptr;ALLOC_ZVAL(this_ptr);INIT_PZVAL_COPY(this_ptr, EX(object));zval_copy_ctor(this_ptr);EX(object) = this_ptr;}}CHECK_EXCEPTION();ZEND_VM_NEXT_OPCODE();
}

static zend_always_inline zval *_get_zval_ptr_cv_BP_VAR_R(zval ***CVs, zend_uint var TSRMLS_DC)
{zval ***ptr = &CV(var);if (UNEXPECTED(*ptr == NULL)) {return *_get_zval_cv_lookup_BP_VAR_R(ptr, var TSRMLS_CC);}return **ptr;
}static zend_never_inline zval **_get_zval_cv_lookup_BP_VAR_R(zval ***ptr, zend_uint var TSRMLS_DC)
{zend_compiled_variable *cv = &CV_DEF_OF(var);if (!EG(active_symbol_table) ||zend_hash_quick_find(EG(active_symbol_table), cv->name, cv->name_len+1, cv->hash_value, (void **)ptr)==FAILURE) {zend_error(E_NOTICE, "Undefined variable: %s", cv->name);return &EG(uninitialized_zval_ptr);}return *ptr;
}

typedef union _zend_function *(*zend_object_get_method_t)(zval **object_ptr, char *method, int method_len, const struct _zend_literal *key TSRMLS_DC);static union _zend_function *zend_std_get_method(zval **object_ptr, char *method_name, int method_len, const zend_literal *key TSRMLS_DC) /* {{{ */
{zend_function *fbc;zval *object = *object_ptr;zend_object *zobj = Z_OBJ_P(object);ulong hash_value;char *lc_method_name;ALLOCA_FLAG(use_heap)if (EXPECTED(key != NULL)) {lc_method_name = Z_STRVAL(key->constant);hash_value = key->hash_value;} else {lc_method_name = do_alloca(method_len+1, use_heap);/* Create a zend_copy_str_tolower(dest, src, src_length); */zend_str_tolower_copy(lc_method_name, method_name, method_len);hash_value = zend_hash_func(lc_method_name, method_len+1);}if (UNEXPECTED(zend_hash_quick_find(&zobj->ce->function_table, lc_method_name, method_len+1, hash_value, (void **)&fbc) == FAILURE)) {if (UNEXPECTED(!key)) {free_alloca(lc_method_name, use_heap);}if (zobj->ce->__call) {return zend_get_user_call_function(zobj->ce, method_name, method_len);} else {return NULL;}}/* Check access level */
    //如果此方法是私有方法，檢查其作用域if (fbc->op_array.fn_flags & ZEND_ACC_PRIVATE) {zend_function *updated_fbc;/* Ensure that if we're calling a private function, we're allowed to do so.* If we're not and __call() handler exists, invoke it, otherwise error out.*/updated_fbc = zend_check_private_int(fbc, Z_OBJ_HANDLER_P(object, get_class_entry)(object TSRMLS_CC), lc_method_name, method_len, hash_value TSRMLS_CC);if (EXPECTED(updated_fbc != NULL)) {fbc = updated_fbc;} else {if (zobj->ce->__call) {fbc = zend_get_user_call_function(zobj->ce, method_name, method_len);} else {zend_error_noreturn(E_ERROR, "Call to %s method %s::%s() from context '%s'", zend_visibility_string(fbc->common.fn_flags), ZEND_FN_SCOPE_NAME(fbc), method_name, EG(scope) ? EG(scope)->name : "");}}} else {/* Ensure that we haven't overridden a private function and end up calling* the overriding public function...*/

　　　　//   zend_do_begin_function_declaration
　　　　　//　　　op_array.scope = is_method?CG(active_class_entry):NULL;

　　　　　　　//　zend_do_fcall_common_helper_SPEC

　　　　　　　　//　　EG(scope) = (fbc->type == ZEND_USER_FUNCTION || !EX(object)) ? fbc->common.scope : NULL;

        if (EG(scope) &&is_derived_class(fbc->common.scope, EG(scope)) &&fbc->op_array.fn_flags & ZEND_ACC_CHANGED) {zend_function *priv_fbc;if (zend_hash_quick_find(&EG(scope)->function_table, lc_method_name, method_len+1, hash_value, (void **) &priv_fbc)==SUCCESS&& priv_fbc->common.fn_flags & ZEND_ACC_PRIVATE&& priv_fbc->common.scope == EG(scope)) {fbc = priv_fbc;}}

 //是否是protected方法if ((fbc->common.fn_flags & ZEND_ACC_PROTECTED)) {/* Ensure that if we're calling a protected function, we're allowed to do so.* If we're not and __call() handler exists, invoke it, otherwise error out.*/if (UNEXPECTED(!zend_check_protected(zend_get_function_root_class(fbc), EG(scope)))) {if (zobj->ce->__call) {fbc = zend_get_user_call_function(zobj->ce, method_name, method_len);} else {zend_error_noreturn(E_ERROR, "Call to %s method %s::%s() from context '%s'", zend_visibility_string(fbc->common.fn_flags), ZEND_FN_SCOPE_NAME(fbc), method_name, EG(scope) ? EG(scope)->name : "");}}}}if (UNEXPECTED(!key)) {free_alloca(lc_method_name, use_heap);}return fbc;
}

檢測調用的方法的作用域，一般來說父類的private方法被子類復制，但由于該方法的scope還是父類，所以不能被調用

static inline zend_function *zend_check_private_int(zend_function *fbc, zend_class_entry *ce, char *function_name_strval, int function_name_strlen, ulong hash_value TSRMLS_DC) /* {{{ */
{if (!ce) {return 0;}/* We may call a private function if:* 1.  The class of our object is the same as the scope, and the private*     function (EX(fbc)) has the same scope.* 2.  One of our parent classes are the same as the scope, and it contains*     a private function with the same name that has the same scope.*/if (fbc->common.scope == ce && EG(scope) == ce) {/* rule #1 checks out ok, allow the function call */return fbc;}/* Check rule #2 */ce = ce->parent;while (ce) {if (ce == EG(scope)) {if (zend_hash_quick_find(&ce->function_table, function_name_strval, function_name_strlen+1, hash_value, (void **) &fbc)==SUCCESS&& fbc->op_array.fn_flags & ZEND_ACC_PRIVATE&& fbc->common.scope == EG(scope)) {return fbc;}break;}ce = ce->parent;}return NULL;
}

3.ZEND_DO_END_FUNCTION_CALL?函數

void zend_do_end_function_call(znode *function_name, znode *result, const znode *argument_list, int is_method, int is_dynamic_fcall TSRMLS_DC) /* {{{ */
{zend_op *opline;if (is_method && function_name && function_name->op_type == IS_UNUSED) {/* clone *///省略} else {opline = get_next_op(CG(active_op_array) TSRMLS_CC);if (!is_method && !is_dynamic_fcall && function_name->op_type==IS_CONST) {//省略} else {opline->opcode = ZEND_DO_FCALL_BY_NAME;SET_UNUSED(opline->op1);}}opline->result.var = get_temporary_variable(CG(active_op_array));opline->result_type = IS_VAR;GET_NODE(result, opline->result)    ;SET_UNUSED(opline->op2);zend_stack_del_top(&CG(function_call_stack));opline->extended_value = Z_LVAL(argument_list->u.constant);
}

4. ZEND_DO_FCALL_BY_NAME 函數

static int ZEND_FASTCALL  ZEND_DO_FCALL_BY_NAME_SPEC_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
{EX(function_state).function = EX(fbc);return zend_do_fcall_common_helper_SPEC(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU);
}

?各種檢測，然后將fbc->op_array 賦值給 EG(active_op_array)

static int ZEND_FASTCALL zend_do_fcall_common_helper_SPEC(ZEND_OPCODE_HANDLER_ARGS)
{USE_OPLINEzend_bool should_change_scope = 0;zend_function *fbc = EX(function_state).function;SAVE_OPLINE();if (UNEXPECTED((fbc->common.fn_flags & (ZEND_ACC_ABSTRACT|ZEND_ACC_DEPRECATED)) != 0)) {if (UNEXPECTED((fbc->common.fn_flags & ZEND_ACC_ABSTRACT) != 0)) {zend_error_noreturn(E_ERROR, "Cannot call abstract method %s::%s()", fbc->common.scope->name, fbc->common.function_name);CHECK_EXCEPTION();ZEND_VM_NEXT_OPCODE(); /* Never reached */}if (UNEXPECTED((fbc->common.fn_flags & ZEND_ACC_DEPRECATED) != 0)) {zend_error(E_DEPRECATED, "Function %s%s%s() is deprecated",fbc->common.scope ? fbc->common.scope->name : "",fbc->common.scope ? "::" : "",fbc->common.function_name);}}if (fbc->common.scope &&!(fbc->common.fn_flags & ZEND_ACC_STATIC) &&!EX(object)) {if (fbc->common.fn_flags & ZEND_ACC_ALLOW_STATIC) {/* FIXME: output identifiers properly */zend_error(E_STRICT, "Non-static method %s::%s() should not be called statically", fbc->common.scope->name, fbc->common.function_name);} else {/* FIXME: output identifiers properly *//* An internal function assumes $this is present and won't check that. So PHP would crash by allowing the call. */zend_error_noreturn(E_ERROR, "Non-static method %s::%s() cannot be called statically", fbc->common.scope->name, fbc->common.function_name);}}if (fbc->type == ZEND_USER_FUNCTION || fbc->common.scope) {should_change_scope = 1;EX(current_this) = EG(This);EX(current_scope) = EG(scope);EX(current_called_scope) = EG(called_scope);EG(This) = EX(object);EG(scope) = (fbc->type == ZEND_USER_FUNCTION || !EX(object)) ? fbc->common.scope : NULL;EG(called_scope) = EX(called_scope);}zend_arg_types_stack_3_pop(&EG(arg_types_stack), &EX(called_scope), &EX(current_object), &EX(fbc));EX(function_state).arguments = zend_vm_stack_push_args(opline->extended_value TSRMLS_CC);LOAD_OPLINE();if (fbc->type == ZEND_INTERNAL_FUNCTION) {//內部函數，不用管    } else if (fbc->type == ZEND_USER_FUNCTION) {EX(original_return_value) = EG(return_value_ptr_ptr);EG(active_symbol_table) = NULL;EG(active_op_array) = &fbc->op_array;EG(return_value_ptr_ptr) = NULL;if (RETURN_VALUE_USED(opline)) {temp_variable *ret = &EX_T(opline->result.var);ret->var.ptr = NULL;EG(return_value_ptr_ptr) = &ret->var.ptr;ret->var.ptr_ptr = &ret->var.ptr;ret->var.fcall_returned_reference = (fbc->common.fn_flags & ZEND_ACC_RETURN_REFERENCE) != 0;}if (EXPECTED(zend_execute == execute)) {if (EXPECTED(EG(exception) == NULL)) {ZEND_VM_ENTER();}} 
}

轉載于:https://www.cnblogs.com/taek/p/4138033.html

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