PHP実行原理の徹底分析(4)：関数呼び出し、php_PHPの徹底分析チュートリアル

php function foo($arg1) { print($arg1); } $bar = 'hello php'; foo($bar);

function_call: namespace_name '(' { $2.u.opline_num = zend_do_begin_function_call(&$1, 1 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(&$1, &$$, &$4, 0, $2.u.opline_num TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C); } | T_NAMESPACE T_NS_SEPARATOR namespace_name '(' { $1.op_type = IS_CONST; ZVAL_EMPTY_STRING(&$1.u.constant); zend_do_build_namespace_name(&$1, &$1, &$3 TSRMLS_CC); $4.u.opline_num = zend_do_begin_function_call(&$1, 0 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(&$1, &$$, &$6, 0, $4.u.opline_num TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C); } | T_NS_SEPARATOR namespace_name '(' { $3.u.opline_num = zend_do_begin_function_call(&$2, 0 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(&$2, &$$, &$5, 0, $3.u.opline_num TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C); } | class_name T_PAAMAYIM_NEKUDOTAYIM T_STRING '(' { $4.u.opline_num = zend_do_begin_class_member_function_call(&$1, &$3 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call($4.u.opline_num?NULL:&$3, &$$, &$6, $4.u.opline_num, $4.u.opline_num TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);} | class_name T_PAAMAYIM_NEKUDOTAYIM variable_without_objects '(' { zend_do_end_variable_parse(&$3, BP_VAR_R, 0 TSRMLS_CC); zend_do_begin_class_member_function_call(&$1, &$3 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(NULL, &$$, &$6, 1, 1 TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);} | variable_class_name T_PAAMAYIM_NEKUDOTAYIM T_STRING '(' { zend_do_begin_class_member_function_call(&$1, &$3 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(NULL, &$$, &$6, 1, 1 TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);} | variable_class_name T_PAAMAYIM_NEKUDOTAYIM variable_without_objects '(' { zend_do_end_variable_parse(&$3, BP_VAR_R, 0 TSRMLS_CC); zend_do_begin_class_member_function_call(&$1, &$3 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(NULL, &$$, &$6, 1, 1 TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);} | variable_without_objects '(' { zend_do_end_variable_parse(&$1, BP_VAR_R, 0 TSRMLS_CC); zend_do_begin_dynamic_function_call(&$1, 0 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(&$1, &$$, &$4, 0, 1 TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);} ;

function_call_parameter_list:
 non_empty_function_call_parameter_list { $$ = $1; }
 | /* empty */ 　　　　　　　　{ Z_LVAL($$.u.constant) = 0; }
;


non_empty_function_call_parameter_list:
 expr_without_variable { Z_LVAL($$.u.constant) = 1; zend_do_pass_param(&$1, ZEND_SEND_VAL, Z_LVAL($$.u.constant) TSRMLS_CC); }
 | variable { Z_LVAL($$.u.constant) = 1; zend_do_pass_param(&$1, ZEND_SEND_VAR, Z_LVAL($$.u.constant) TSRMLS_CC); }
 | '&' w_variable { Z_LVAL($$.u.constant) = 1; zend_do_pass_param(&$2, ZEND_SEND_REF, Z_LVAL($$.u.constant) TSRMLS_CC); }
 | non_empty_function_call_parameter_list ',' expr_without_variable { Z_LVAL($$.u.constant)=Z_LVAL($1.u.constant)+1; zend_do_pass_param(&$3, ZEND_SEND_VAL, Z_LVAL($$.u.constant) TSRMLS_CC); }
 | non_empty_function_call_parameter_list ',' variable { Z_LVAL($$.u.constant)=Z_LVAL($1.u.constant)+1; zend_do_pass_param(&$3, ZEND_SEND_VAR, Z_LVAL($$.u.constant) TSRMLS_CC); }
 | non_empty_function_call_parameter_list ',' '&' w_variable { Z_LVAL($$.u.constant)=Z_LVAL($1.u.constant)+1; zend_do_pass_param(&$4, ZEND_SEND_REF, Z_LVAL($$.u.constant) TSRMLS_CC); }
;

namespace MyProject { function foo($arg1) { print($arg1); } } namespace { $bar = 'hello php'; MyProject\foo($bar);// 以类似“全路径”的fullname来调用函数，则namespace_name为MyProject\foo }

zend_do_begin_function_call-->zend_do_pass_param-->zend_do_end_function_call

 开始 解析参数 结束

zend_function *function; char *lcname; char *is_compound = memchr(Z_STRVAL(function_name->u.constant), '\\', Z_STRLEN(function_name->u.constant)); // 将函数名进行修正，例如带上命名空间作为前缀等 zend_resolve_non_class_name(function_name, check_namespace TSRMLS_CC); // 能进入该分支，说明在一个命名空间下以shortname调用函数，会生成一条DO_FCALL_BY_NAME指令 if (check_namespace && CG(current_namespace) && !is_compound) { /* We assume we call function from the current namespace if it is not prefixed. */ /* In run-time PHP will check for function with full name and internal function with short name */ zend_do_begin_dynamic_function_call(function_name, 1 TSRMLS_CC); return 1; } // 转成小写，因为CG(function_table)中的函数名都是小写 lcname = zend_str_tolower_dup(function_name->u.constant.value.str.val, function_name->u.constant.value.str.len); // 如果function_table中找不到该函数，则也尝试生成DO_FCALL_BY_NAME指令 if ((zend_hash_find(CG(function_table), lcname, function_name->u.constant.value.str.len+1, (void **) &function) == FAILURE) || ((CG(compiler_options) & ZEND_COMPILE_IGNORE_INTERNAL_FUNCTIONS) && (function->type == ZEND_INTERNAL_FUNCTION))) { zend_do_begin_dynamic_function_call(function_name, 0 TSRMLS_CC); efree(lcname); return 1; /* Dynamic */ } efree(function_name->u.constant.value.str.val); function_name->u.constant.value.str.val = lcname; // 压入CG(function_call_stack) zend_stack_push(&CG(function_call_stack), (void *) &function, sizeof(zend_function *)); zend_do_extended_fcall_begin(TSRMLS_C); return 0;

php namespace MyProject; function foo($arg1) { print($arg1); } $bar = 'hello php';
 foo($bar); // zend_resolve_non_class_name会将foo处理成MyProject\foo namespace\foo($bar); // 在进入zend_do_begin_function_call之前，函数名已经被扩展成\MyProject\foo，再经过zend_resolve_non_class_name，将\MyProject\foo处理成MyProject\foo \MyProject\foo($bar); // zend_resolve_non_class_name会将\MyProject\foo处理成MyProject\foo

php namespace MyProject\sub; function foo($arg1) { print($arg1); } namespace MyProject; $bar = 'hello php'; sub\foo($bar); // 以sub\foo调用函数，并不算shortname，因为存在\

php $bar = 'hello php'; // 先调用 foo($bar); // 后定义 function foo($arg1) { print($arg1); }

php function foo($arg1) { print($arg1); } $bar = 'hello php'; foo(strlen($bar)); // 首先foo入栈，然后分析参数strlen($bar)，发现依然是个函数，于是strlen入栈，再分析参数$bar，此时弹出对应的函数正好为strlen。

php function foo($arg1) { print($arg1); } $bar = 'hello php'; $func = 'foo'; $func($bar); // 我们以变量$func作为函数名，试图调用函数foo，$func类型是IS_CV

function_call:
 ... | variable_without_objects '(' { zend_do_end_variable_parse(&$1, BP_VAR_R, 0 TSRMLS_CC); zend_do_begin_dynamic_function_call(&$1, 0 TSRMLS_CC); } function_call_parameter_list ')' { zend_do_end_function_call(&$1, &$$, &$4, 0, 1 TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);}

function foo($arg1) { print($arg1); } $bar = 'hello php'; $func = 'foo'; $ref_func = 'func'; $$ref_func($bar); // 以可变变量的形式来调用函数，$$ref_func类型是IS_VAR

void zend_do_begin_dynamic_function_call(znode *function_name, int ns_call TSRMLS_DC) /* {{{ */ { unsigned char *ptr = NULL; zend_op *opline, *opline2; // 拿一条zend_op opline = get_next_op(CG(active_op_array) TSRMLS_CC); // 参数ns_call表名是否以shortname在命名空间中调用函数 if (ns_call) { char *slash; int prefix_len, name_len; /* In run-time PHP will check for function with full name and internal function with short name */ // 第一条指令是ZEND_INIT_NS_FCALL_BY_NAME opline->opcode = ZEND_INIT_NS_FCALL_BY_NAME; opline->op2 = *function_name; opline->extended_value = 0; opline->op1.op_type = IS_CONST; Z_TYPE(opline->op1.u.constant) = IS_STRING; Z_STRVAL(opline->op1.u.constant) = zend_str_tolower_dup(Z_STRVAL(opline->op2.u.constant), Z_STRLEN(opline->op2.u.constant)); Z_STRLEN(opline->op1.u.constant) = Z_STRLEN(opline->op2.u.constant); opline->extended_value = zend_hash_func(Z_STRVAL(opline->op1.u.constant), Z_STRLEN(opline->op1.u.constant) + 1); // 再拿一条zend_op，指令为ZEND_OP_DATA slash = zend_memrchr(Z_STRVAL(opline->op1.u.constant), '\\', Z_STRLEN(opline->op1.u.constant)); prefix_len = slash-Z_STRVAL(opline->op1.u.constant)+1; name_len = Z_STRLEN(opline->op1.u.constant)-prefix_len; opline2 = get_next_op(CG(active_op_array) TSRMLS_CC); opline2->opcode = ZEND_OP_DATA; opline2->op1.op_type = IS_CONST; Z_TYPE(opline2->op1.u.constant) = IS_LONG; if(!slash) { zend_error(E_CORE_ERROR, "Namespaced name %s should contain slash", Z_STRVAL(opline->op1.u.constant)); } /* this is the length of namespace prefix */ Z_LVAL(opline2->op1.u.constant) = prefix_len; /* this is the hash of the non-prefixed part, lowercased */ opline2->extended_value = zend_hash_func(slash+1, name_len+1); SET_UNUSED(opline2->op2); } else { // 第一条指令是ZEND_INIT_FCALL_BY_NAME opline->opcode = ZEND_INIT_FCALL_BY_NAME; opline->op2 = *function_name; // 先调用，再定义 if (opline->op2.op_type == IS_CONST) { opline->op1.op_type = IS_CONST; Z_TYPE(opline->op1.u.constant) = IS_STRING; Z_STRVAL(opline->op1.u.constant) = zend_str_tolower_dup(Z_STRVAL(opline->op2.u.constant), Z_STRLEN(opline->op2.u.constant)); Z_STRLEN(opline->op1.u.constant) = Z_STRLEN(opline->op2.u.constant); opline->extended_value = zend_hash_func(Z_STRVAL(opline->op1.u.constant), Z_STRLEN(opline->op1.u.constant) + 1); } // 以变量当函数名来调用 else { opline->extended_value = 0; SET_UNUSED(opline->op1); } } // 将NULL压入CG(function_call_stack) zend_stack_push(&CG(function_call_stack), (void *) &ptr, sizeof(zend_function *)); zend_do_extended_fcall_begin(TSRMLS_C); }

php namespace MyProject; function foo($arg1) { print($arg1); } $bar = 'hello php'; foo($bar);

expr_without_variable { Z_LVAL($$.u.constant) = 1; zend_do_pass_param(&$1, ZEND_SEND_VAL, Z_LVAL($$.u.constant) TSRMLS_CC); } variable { Z_LVAL($$.u.constant) = 1; zend_do_pass_param(&$1, ZEND_SEND_VAR, Z_LVAL($$.u.constant) TSRMLS_CC); } '&' w_variable { Z_LVAL($$.u.constant) = 1; zend_do_pass_param(&$2, ZEND_SEND_REF, Z_LVAL($$.u.constant) TSRMLS_CC); }

// 函数已定义，则根据函数的定义，来决定send_by_reference是否传引用 if (function_ptr) { if (ARG_MAY_BE_SENT_BY_REF(function_ptr, (zend_uint) offset)) { ... } else { // 要么为0，要么为ZEND_ARG_SEND_BY_REF send_by_reference = ARG_SHOULD_BE_SENT_BY_REF(function_ptr, (zend_uint) offset) ? ZEND_ARG_SEND_BY_REF : 0; } } // 函数为定义，先统一将send_by_reference置为0 else { send_by_reference = 0; } // 如果用户传递的参数，本身就是一次函数调用，则将op改成ZEND_SEND_VAR_NO_REF if (op == ZEND_SEND_VAR && zend_is_function_or_method_call(param)) { /* Method call */ op = ZEND_SEND_VAR_NO_REF; send_function = ZEND_ARG_SEND_FUNCTION; } // 如果用户传递的参数，是一个表达式，并且结果会产生中间变量，则也将op改成ZEND_SEND_VAR_NO_REF else if (op == ZEND_SEND_VAL && (param->op_type & (IS_VAR|IS_CV))) { op = ZEND_SEND_VAR_NO_REF; }

// 如果根据函数定义需要传递引用，且实际传递的参数是变量，则将op改成ZEND_SEND_REF if (op!=ZEND_SEND_VAR_NO_REF && send_by_reference==ZEND_ARG_SEND_BY_REF) { /* change to passing by reference */ switch (param->op_type) { case IS_VAR: case IS_CV: op = ZEND_SEND_REF; break; default: zend_error(E_COMPILE_ERROR, "Only variables can be passed by reference"); break; } } // 如果实际传递的参数是变量，调用zend_do_end_variable_parse处理链式调用 if (original_op == ZEND_SEND_VAR) { switch (op) { case ZEND_SEND_VAR_NO_REF: zend_do_end_variable_parse(param, BP_VAR_R, 0 TSRMLS_CC); break; case ZEND_SEND_VAR: if (function_ptr) { zend_do_end_variable_parse(param, BP_VAR_R, 0 TSRMLS_CC); } else { zend_do_end_variable_parse(param, BP_VAR_FUNC_ARG, offset TSRMLS_CC); } break; case ZEND_SEND_REF: zend_do_end_variable_parse(param, BP_VAR_W, 0 TSRMLS_CC); break; } }

function foo(&$a) { print($a); } foo($bar == 1); // 抛错 "Only variables can be passed by reference"

// 获取下一条zend op指令 opline = get_next_op(CG(active_op_array) TSRMLS_CC); // extended_value加上不同的附加信息 if (op == ZEND_SEND_VAR_NO_REF) { if (function_ptr) { opline->extended_value = ZEND_ARG_COMPILE_TIME_BOUND | send_by_reference | send_function; } else { opline->extended_value = send_function; } } else { if (function_ptr) { opline->extended_value = ZEND_DO_FCALL; } else { opline->extended_value = ZEND_DO_FCALL_BY_NAME; } } // 设置opcode、op1、op2等 opline->opcode = op; opline->op1 = *param; opline->op2.u.opline_num = offset; SET_UNUSED(opline->op2);

zend_op *opline; // 这段逻辑分支现在已经走不到了 if (is_method && function_name && function_name->op_type == IS_UNUSED) { /* clone */ if (Z_LVAL(argument_list->u.constant) != 0) { zend_error(E_WARNING, "Clone method does not require arguments"); } opline = &CG(active_op_array)->opcodes[Z_LVAL(function_name->u.constant)]; } else { opline = get_next_op(CG(active_op_array) TSRMLS_CC); // 函数，名称确定，非dynamic_fcall，函数则生成ZEND_DO_FCALL指令 if (!is_method && !is_dynamic_fcall && function_name->op_type==IS_CONST) { opline->opcode = ZEND_DO_FCALL; opline->op1 = *function_name; ZVAL_LONG(&opline->op2.u.constant, zend_hash_func(Z_STRVAL(function_name->u.constant), Z_STRLEN(function_name->u.constant) + 1)); } // 否则生成ZEND_DO_FCALL_BY_NAME指令 else { opline->opcode = ZEND_DO_FCALL_BY_NAME; SET_UNUSED(opline->op1); } } // 生成临时变量索引，函数的调用，返回的znode必然是IS_VAR opline->result.u.var = get_temporary_variable(CG(active_op_array)); opline->result.op_type = IS_VAR; *result = opline->result; SET_UNUSED(opline->op2); // 从CG(function_call_stack)弹出当前被调用的函数 zend_stack_del_top(&CG(function_call_stack)); // 传参个数 opline->extended_value = Z_LVAL(argument_list->u.constant);