<?php
function test()
{
echo "abc";
}
test();
?>
结论:
一 编译
a.对 函数声明进行词法分析和语法分析：在语法分析中的函数zend_do_begin_function_declaration 作用是： 初始化zend_op_array,填充 function_name ,line_start ,设定相应opcode:ZEND_DECLARE_FUNCTION, 以key为function_name, value为 zend_op_array，存入CG(function_table)中;zend_do_end_function_declaration作用为： 填充zend_op_array中的line_end
b.对 函数调用进行词法分析和语法分析： 语法分析中的函数 zend_do_begin_function_call 作用是：将函数名转化为小写，zend_do_end_function_call中设定opcode:ZEND_DO_FCALL, op1为function_name,op2为no use
二 执行
c.执行a中的hanlder ZEND_DECLARE_FUNCTION,如果函数名重复出现，则报错
d.执行b中的handler ZEND_DO_FCALL ,
1)词法分析，提取function 关键字
<ST_IN_SCRIPTING>"function" {
return T_FUNCTION;
}
2)语法分析，每一个字符串表达式后面跟着一个方法，此方法是用来生成opcode
function:
T_FUNCTION { $$.u.op.opline_num = CG(zend_lineno); }
;
unticked_function_declaration_statement:
function is_reference T_STRING { zend_do_begin_function_declaration(&$1, &$3, 0, $2.op_type, NULL TSRMLS_CC); }
'(' parameter_list ')' '{' inner_statement_list '}' { zend_do_end_function_declaration(&$1 TSRMLS_CC); }
;
parameter_list:
non_empty_parameter_list
| /* empty */
;
//用来处理参数
non_empty_parameter_list:
optional_class_type T_VARIABLE { $$.op_type = IS_UNUSED; $$.u.op.num=1; zend_do_receive_arg(ZEND_RECV, &$2, &$$, NULL, &$1, 0 TSRMLS_CC); } //$$.u.op.num=1 说明是第一个参数，也只存在一个参数
| optional_class_type '&' T_VARIABLE { $$.op_type = IS_UNUSED; $$.u.op.num=1; zend_do_receive_arg(ZEND_RECV, &$3, &$$, NULL, &$1, 1 TSRMLS_CC); } //这种方法已经取消了，估计是向下兼容
| optional_class_type '&' T_VARIABLE '=' static_scalar { $$.op_type = IS_UNUSED; $$.u.op.num=1; zend_do_receive_arg(ZEND_RECV_INIT, &$3, &$$, &$5, &$1, 1 TSRMLS_CC); }
| optional_class_type T_VARIABLE '=' static_scalar { $$.op_type = IS_UNUSED; $$.u.op.num=1; zend_do_receive_arg(ZEND_RECV_INIT, &$2, &$$, &$4, &$1, 0 TSRMLS_CC); }
| non_empty_parameter_list ',' optional_class_type T_VARIABLE { $$=$1; $$.u.op.num++; zend_do_receive_arg(ZEND_RECV, &$4, &$$, NULL, &$3, 0 TSRMLS_CC); } // $$.u.op.num++递增，多个参数，用逗号分隔
| non_empty_parameter_list ',' optional_class_type '&' T_VARIABLE { $$=$1; $$.u.op.num++; zend_do_receive_arg(ZEND_RECV, &$5, &$$, NULL, &$3, 1 TSRMLS_CC); }
| non_empty_parameter_list ',' optional_class_type '&' T_VARIABLE '=' static_scalar { $$=$1; $$.u.op.num++; zend_do_receive_arg(ZEND_RECV_INIT, &$5, &$$, &$7, &$3, 1 TSRMLS_CC); }
| non_empty_parameter_list ',' optional_class_type T_VARIABLE '=' static_scalar { $$=$1; $$.u.op.num++; zend_do_receive_arg(ZEND_RECV_INIT, &$4, &$$, &$6, &$3, 0 TSRMLS_CC); }
;
对函数头进行语法分析 ，主要 往zend_op_array中填充信息，比如 函数开始行号
void zend_do_begin_function_declaration(znode *function_token, znode *function_name, int is_method, int return_reference, znode *fn_flags_znode TSRMLS_DC) /* {{{ */
{
zend_op_array op_array;
char *name = function_name->u.constant.value.str.val;
int name_len = function_name->u.constant.value.str.len;
int function_begin_line = function_token->u.op.opline_num;
zend_uint fn_flags;
const char *lcname;
zend_bool orig_interactive;
ALLOCA_FLAG(use_heap)
if (is_method) {
//忽略，这是针对类方法的
fn_flags = Z_LVAL(fn_flags_znode->u.constant); /* must be done *after* the above check */
} else {
fn_flags = 0;
}
if ((fn_flags & ZEND_ACC_STATIC) && (fn_flags & ZEND_ACC_ABSTRACT) && !(CG(active_class_entry)->ce_flags & ZEND_ACC_INTERFACE)) {
zend_error(E_STRICT, "Static function %s%s%s() should not be abstract", is_method ? CG(active_class_entry)->name : "", is_method ? "::" : "", Z_STRVAL(function_name->u.constant));
}
function_token->u.op_array = CG(active_op_array);//保存之前的CG(active_op_array),zend_do_end_funciton_declaration函数里将恢复CG(active_op_array)
orig_interactive = CG(interactive);
CG(interactive) = 0;
init_op_array(&op_array, ZEND_USER_FUNCTION, INITIAL_OP_ARRAY_SIZE TSRMLS_CC);
CG(interactive) = orig_interactive;
op_array.function_name = name; //填充functio_name字段
if (return_reference) {
op_array.fn_flags |= ZEND_ACC_RETURN_REFERENCE;
}
op_array.fn_flags |= fn_flags;
op_array.scope = is_method?CG(active_class_entry):NULL;
op_array.prototype = NULL;
op_array.line_start = zend_get_compiled_lineno(TSRMLS_C); //填充 函数首行行号
if (is_method) {
//忽略，这是针对类方法的处理
} else {
zend_op *opline = get_next_op(CG(active_op_array) TSRMLS_CC);
zval key;
if (CG(current_namespace)) { //针对命名空间的
/* Prefix function name with current namespace name */
znode tmp;
tmp.u.constant = *CG(current_namespace);
zval_copy_ctor(&tmp.u.constant);
zend_do_build_namespace_name(&tmp, &tmp, function_name TSRMLS_CC);
op_array.function_name = Z_STRVAL(tmp.u.constant);
name_len = Z_STRLEN(tmp.u.constant);
lcname = zend_str_tolower_dup(Z_STRVAL(tmp.u.constant), name_len);
} else {
lcname = zend_str_tolower_dup(name, name_len); //函数名设置为小写
}
opline->opcode = ZEND_DECLARE_FUNCTION; //设置执行时的handler,在这里，如果函数名重复出现，会提示 已声明过函数了
opline->op1_type = IS_CONST;
build_runtime_defined_function_key(&key, lcname, name_len TSRMLS_CC);
opline->op1.constant = zend_add_literal(CG(active_op_array), &key TSRMLS_CC); //将key存入到zend_op_array中的literals中，他本身是个数组，即op1.constant是键，值是key
Z_HASH_P(&CONSTANT(opline->op1.constant)) = zend_hash_func(Z_STRVAL(CONSTANT(opline->op1.constant)), Z_STRLEN(CONSTANT(opline->op1.constant)));
opline->op2_type = IS_CONST;
LITERAL_STRINGL(opline->op2, lcname, name_len, 0); //opline->op2.constant设置为 literals数组中的键,值为lcname
CALCULATE_LITERAL_HASH(opline->op2.constant);
opline->extended_value = ZEND_DECLARE_FUNCTION;
//放入CG中函数符号表，上面的key为 函数名文件名称，不知道为什么这样写？为什么不把函数名 直接存入 函数符号表？
zend_hash_quick_update(CG(function_table), Z_STRVAL(key), Z_STRLEN(key), Z_HASH_P(&CONSTANT(opline->op1.constant)), &op_array, sizeof(zend_op_array), (void **) &CG(active_op_array));
zend_stack_push(&CG(context_stack), (void *) &CG(context), sizeof(CG(context)));
zend_init_compiler_context(TSRMLS_C);
}
//忽略
}
}
ZEND_API char *zend_str_tolower_copy(char *dest, const char *source, unsigned int length) /* {{{ */
{
register unsigned char *str = (unsigned char*)source;
register unsigned char *result = (unsigned char*)dest;
register unsigned char *end = str + length;
while (str < end) {
*result++ = zend_tolower((int)*str++);
}
*result = ' ';
return dest;
}
/* }}} */
ZEND_API char *zend_str_tolower_dup(const char *source, unsigned int length) /* {{{ */
{
return zend_str_tolower_copy((char *)emalloc(length+1), source, length);
}
static void build_runtime_defined_function_key(zval *result, const char *name, int name_length TSRMLS_DC) /* {{{ */
{
char char_pos_buf[32];
uint char_pos_len;
const char *filename;
char_pos_len = zend_sprintf(char_pos_buf, "%p", LANG_SCNG(yy_text));
if (CG(active_op_array)->filename) {
filename = CG(active_op_array)->filename;
} else {
filename = "-";
}
/* NULL, name length, filename length, last accepting char position length */
result->value.str.len = 1+name_length+strlen(filename)+char_pos_len;
/* must be binary safe */
result->value.str.val = (char *) safe_emalloc(result->value.str.len, 1, 1);
result->value.str.val[0] = ' ';
sprintf(result->value.str.val+1, "%s%s%s", name, filename, char_pos_buf);
result->type = IS_STRING;
Z_SET_REFCOUNT_P(result, 1);
}
static inline void zend_insert_literal(zend_op_array *op_array, const zval *zv, int literal_position TSRMLS_DC) /* {{{ */
{
if (Z_TYPE_P(zv) == IS_STRING || Z_TYPE_P(zv) == IS_CONSTANT) {
zval *z = (zval*)zv;
Z_STRVAL_P(z) = (char*)zend_new_interned_string(Z_STRVAL_P(zv), Z_STRLEN_P(zv) + 1, 1 TSRMLS_CC);
}
CONSTANT_EX(op_array, literal_position) = *zv;
Z_SET_REFCOUNT(CONSTANT_EX(op_array, literal_position), 2);
Z_SET_ISREF(CONSTANT_EX(op_array, literal_position));
op_array->literals[literal_position].hash_value = 0;
op_array->literals[literal_position].cache_slot = -1;
}
/* }}} */
/* Is used while compiling a function, using the context to keep track
of an approximate size to avoid to relocate to often.
Literals are truncated to actual size in the second compiler pass (pass_two()). */
int zend_add_literal(zend_op_array *op_array, const zval *zv TSRMLS_DC) /* {{{ */
{
int i = op_array->last_literal;
op_array->last_literal++;
if (i >= CG(context).literals_size) {
while (i >= CG(context).literals_size) {
CG(context).literals_size += 16; /* FIXME */
}
op_array->literals = (zend_literal*)erealloc(op_array->literals, CG(context).literals_size * sizeof(zend_literal));
}
zend_insert_literal(op_array, zv, i TSRMLS_CC);
return i;
}
zend_op *get_next_op(zend_op_array *op_array TSRMLS_DC)
{
zend_uint next_op_num = op_array->last++;
zend_op *next_op;
if (next_op_num >= CG(context).opcodes_size) {
if (op_array->fn_flags & ZEND_ACC_INTERACTIVE) {
/* we messed up */
zend_printf("Ran out of opcode space!
"
"You should probably consider writing this huge script into a file!
");
zend_bailout();
}
CG(context).opcodes_size *= 4;
op_array_alloc_ops(op_array, CG(context).opcodes_size);
}
next_op = &(op_array->opcodes[next_op_num]);
init_op(next_op TSRMLS_CC);
return next_op;
}
对函数体进行语法分析，主要是往zend_op_array中填充 函数结束行号，使用 pass_two函数，遍历CG(active_op_array)中的opcodes，设置zend_op 的handler
void zend_do_end_function_declaration(const znode *function_token TSRMLS_DC) /* {{{ */
{
char lcname[16];
int name_len;
zend_do_extended_info(TSRMLS_C);
zend_do_return(NULL, 0 TSRMLS_CC);
pass_two(CG(active_op_array) TSRMLS_CC);
zend_release_labels(TSRMLS_C);
if (CG(active_class_entry)) {
zend_check_magic_method_implementation(CG(active_class_entry), (zend_function*)CG(active_op_array), E_COMPILE_ERROR TSRMLS_CC);
} else {
/* we don't care if the function name is longer, in fact lowercasing only
* the beginning of the name speeds up the check process */
name_len = strlen(CG(active_op_array)->function_name);
zend_str_tolower_copy(lcname, CG(active_op_array)->function_name, MIN(name_len, sizeof(lcname)-1));
lcname[sizeof(lcname)-1] = ' '; /* zend_str_tolower_copy won't necessarily set the zero byte */
if (name_len == sizeof(ZEND_AUTOLOAD_FUNC_NAME) - 1 && !memcmp(lcname, ZEND_AUTOLOAD_FUNC_NAME, sizeof(ZEND_AUTOLOAD_FUNC_NAME)) && CG(active_op_array)->num_args != 1) {
zend_error(E_COMPILE_ERROR, "%s() must take exactly 1 argument", ZEND_AUTOLOAD_FUNC_NAME);
}
}
//得到函数体结束的 行
CG(active_op_array)->line_end = zend_get_compiled_lineno(TSRMLS_C);
CG(active_op_array) = function_token->u.op_array;
/* Pop the switch and foreach seperators */
zend_stack_del_top(&CG(switch_cond_stack));
zend_stack_del_top(&CG(foreach_copy_stack));
}
ZEND_API int pass_two(zend_op_array *op_array TSRMLS_DC)
{
zend_op *opline, *end;
if (op_array->type!=ZEND_USER_FUNCTION && op_array->type!=ZEND_EVAL_CODE) {
return 0;
}
if (CG(compiler_options) & ZEND_COMPILE_EXTENDED_INFO) {
zend_update_extended_info(op_array TSRMLS_CC);
}
if (CG(compiler_options) & ZEND_COMPILE_HANDLE_OP_ARRAY) {
zend_llist_apply_with_argument(&zend_extensions, (llist_apply_with_arg_func_t) zend_extension_op_array_handler, op_array TSRMLS_CC);
}
if (!(op_array->fn_flags & ZEND_ACC_INTERACTIVE) && CG(context).vars_size != op_array->last_var) {
op_array->vars = (zend_compiled_variable *) erealloc(op_array->vars, sizeof(zend_compiled_variable)*op_array->last_var);
CG(context).vars_size = op_array->last_var;
}
if (!(op_array->fn_flags & ZEND_ACC_INTERACTIVE) && CG(context).opcodes_size != op_array->last) {
op_array->opcodes = (zend_op *) erealloc(op_array->opcodes, sizeof(zend_op)*op_array->last);
CG(context).opcodes_size = op_array->last;
}
if (!(op_array->fn_flags & ZEND_ACC_INTERACTIVE) && CG(context).literals_size != op_array->last_literal) {
op_array->literals = (zend_literal*)erealloc(op_array->literals, sizeof(zend_literal) * op_array->last_literal);
CG(context).literals_size = op_array->last_literal;
}
opline = op_array->opcodes;
end = opline + op_array->last;
while (opline < end) {
if (opline->op1_type == IS_CONST) {
opline->op1.zv = &op_array->literals[opline->op1.constant].constant;
}
if (opline->op2_type == IS_CONST) {
opline->op2.zv = &op_array->literals[opline->op2.constant].constant;
}
switch (opline->opcode) {
case ZEND_GOTO:
if (Z_TYPE_P(opline->op2.zv) != IS_LONG) {
zend_resolve_goto_label(op_array, opline, 1 TSRMLS_CC);
}
/* break omitted intentionally */
case ZEND_JMP:
opline->op1.jmp_addr = &op_array->opcodes[opline->op1.opline_num];
break;
case ZEND_JMPZ:
case ZEND_JMPNZ:
case ZEND_JMPZ_EX:
case ZEND_JMPNZ_EX:
case ZEND_JMP_SET:
case ZEND_JMP_SET_VAR:
opline->op2.jmp_addr = &op_array->opcodes[opline->op2.opline_num];
break;
}
ZEND_VM_SET_OPCODE_HANDLER(opline);
opline++;
}
op_array->fn_flags |= ZEND_ACC_DONE_PASS_TWO;
return 0;
}
ZEND_API void zend_vm_set_opcode_handler(zend_op* op)
{
op->handler = zend_vm_get_opcode_handler(zend_user_opcodes[op->opcode], op);
}
static opcode_handler_t zend_vm_get_opcode_handler(zend_uchar opcode, zend_op* op)
{
static const int zend_vm_decode[] = {
_UNUSED_CODE, /* 0 */
_CONST_CODE, /* 1 = IS_CONST */
_TMP_CODE, /* 2 = IS_TMP_VAR */
_UNUSED_CODE, /* 3 */
_VAR_CODE, /* 4 = IS_VAR */
_UNUSED_CODE, /* 5 */
_UNUSED_CODE, /* 6 */
_UNUSED_CODE, /* 7 */
_UNUSED_CODE, /* 8 = IS_UNUSED */
_UNUSED_CODE, /* 9 */
_UNUSED_CODE, /* 10 */
_UNUSED_CODE, /* 11 */
_UNUSED_CODE, /* 12 */
_UNUSED_CODE, /* 13 */
_UNUSED_CODE, /* 14 */
_UNUSED_CODE, /* 15 */
_CV_CODE /* 16 = IS_CV */
};
return zend_opcode_handlers[opcode * 25 + zend_vm_decode[op->op1_type] * 5 + zend_vm_decode[op->op2_type]]; //通过 zend_op中的opcode 和左右值类型 ，计算出实际的handler;zend_opcode_handlers是一个巨大的数组，里面都是指针函数
}
如果函数体中，还有其他数据，例如赋值，就把相应opcode放到zend_op_array中的opcodes中
static int ZEND_FASTCALL ZEND_DECLARE_FUNCTION_SPEC_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
{
USE_OPLINE
SAVE_OPLINE();
do_bind_function(EX(op_array), opline, EG(function_table), 0);
CHECK_EXCEPTION();
ZEND_VM_NEXT_OPCODE();
}
//在执行期间，将函数名放入 EG(function_table)中，如果发现已经有了，则报错
ZEND_API int do_bind_function(const zend_op_array *op_array, zend_op *opline, HashTable *function_table, zend_bool compile_time) /* {{{ */
{
zend_function *function;
zval *op1, *op2;
if (compile_time) {
op1 = &CONSTANT_EX(op_array, opline->op1.constant);
op2 = &CONSTANT_EX(op_array, opline->op2.constant);
} else {
op1 = opline->op1.zv; //这里的op1.zv的值是通过上面的pass_two这个函数中得到的，他会遍历zend_op_array中的opcodes,如果op1_type为 IS_CONST，就会进行把zend_op_array中的literals相应的值赋给op1.zv
op2 = opline->op2.zv; //同上
}
//这里的op1为上面的 函数名文件名称，从EG(function_table)中取出，值赋给function
zend_hash_quick_find(function_table, Z_STRVAL_P(op1), Z_STRLEN_P(op1), Z_HASH_P(op1), (void *) &function);
//将键为op2（只有函数名），值为function,插入到EG(function)中，如果插入失败，说明函数多次被插入，要报函数已被声明的提示
if (zend_hash_quick_add(function_table, Z_STRVAL_P(op2), Z_STRLEN_P(op2)+1, Z_HASH_P(op2), function, sizeof(zend_function), NULL)==FAILURE) {
int error_level = compile_time ? E_COMPILE_ERROR : E_ERROR;
zend_function *old_function;
if (zend_hash_quick_find(function_table, Z_STRVAL_P(op2), Z_STRLEN_P(op2)+1, Z_HASH_P(op2), (void *) &old_function)==SUCCESS
&& old_function->type == ZEND_USER_FUNCTION
&& old_function->op_array.last > 0) {
zend_error(error_level, "Cannot redeclare %s() (previously declared in %s:%d)",
function->common.function_name,
old_function->op_array.filename,
old_function->op_array.opcodes[0].lineno);
} else {
zend_error(error_level, "Cannot redeclare %s()", function->common.function_name);
}
return FAILURE;
} else {
(*function->op_array.refcount)++;
function->op_array.static_variables = NULL; /* NULL out the unbound function */
return SUCCESS;
}
}
对于 调用函数时的编译
function_call:
namespace_name '(' { $2.u.op.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.op.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.op.opline_num = zend_do_begin_function_call(&$1, 0 TSRMLS_CC); }
function_call_parameter_list
')' { zend_do_end_function_call(&$1, &$$, &$6, 0, $4.u.op.opline_num TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C); }
| T_NS_SEPARATOR namespace_name '(' { $3.u.op.opline_num = zend_do_begin_function_call(&$2, 0 TSRMLS_CC); }
function_call_parameter_list
')' { zend_do_end_function_call(&$2, &$$, &$5, 0, $3.u.op.opline_num TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C); }
| class_name T_PAAMAYIM_NEKUDOTAYIM variable_name '(' { $4.u.op.opline_num = zend_do_begin_class_member_function_call(&$1, &$3 TSRMLS_CC); }
function_call_parameter_list
')' { zend_do_end_function_call($4.u.op.opline_num?NULL:&$3, &$$, &$6, $4.u.op.opline_num, $4.u.op.opline_num TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);}
| class_name T_PAAMAYIM_NEKUDOTAYIM variable_without_objects '(' { zend_do_end_variable_parse(&$3, BP_VAR_R, 0 TSRMLS_CC); zend_do_begin_class_member_function_call(&$1, &$3 TSRMLS_CC); }
function_call_parameter_list
')' { zend_do_end_function_call(NULL, &$$, &$6, 1, 1 TSRMLS_CC); zend_do_extended_fcall_end(TSRMLS_C);}
| variable_class_name T_PAAMAYIM_NEKUDOTAYIM variable_name '(' { 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);}
;
int zend_do_begin_function_call(znode *function_name, zend_bool check_namespace TSRMLS_DC) /* {{{ */
{
zend_function *function;
char *lcname;
char *is_compound = memchr(Z_STRVAL(function_name->u.constant), '\', Z_STRLEN(function_name->u.constant));
zend_resolve_non_class_name(function_name, check_namespace TSRMLS_CC);
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;
}
lcname = zend_str_tolower_dup(function_name->u.constant.value.str.val, function_name->u.constant.value.str.len); //将函数名称转化为小写，因为调用的时候，函数名可能是大写的
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;
zend_stack_push(&CG(function_call_stack), (void *) &function, sizeof(zend_function *));
zend_do_extended_fcall_begin(TSRMLS_C);
return 0;
}
ZEND_API int zend_stack_push(zend_stack *stack, const void *element, int size)
{
if (stack->top >= stack->max) { /* we need to allocate more memory */
stack->elements = (void **) erealloc(stack->elements,
(sizeof(void **) * (stack->max += STACK_BLOCK_SIZE)));
if (!stack->elements) {
return FAILURE;
}
}
stack->elements[stack->top] = (void *) emalloc(size);
memcpy(stack->elements[stack->top], element, size);
return stack->top++;
}
typedef struct _zend_stack {
int top, max;
void **elements;
} zend_stack;
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) { //类方法
/* 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 { //普通方法
opline = get_next_op(CG(active_op_array) TSRMLS_CC);
if (!is_method && !is_dynamic_fcall && function_name->op_type==IS_CONST) {
opline->opcode = ZEND_DO_FCALL; //设置执行时的handler
SET_NODE(opline->op1, function_name); //设置左值为 方法的名称
CALCULATE_LITERAL_HASH(opline->op1.constant);
GET_CACHE_SLOT(opline->op1.constant);
} 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);
}
#define CONSTANT_EX(op_array, op)
(op_array)->literals[op].constant
#define CONSTANT(op)
CONSTANT_EX(CG(active_op_array), op)
#define SET_NODE(target, src) do {
target ## _type = (src)->op_type;
if ((src)->op_type == IS_CONST) {
target.constant = zend_add_literal(CG(active_op_array), &(src)->u.constant TSRMLS_CC);
} else {
target = (src)->u.op;
}
} while (0)
#define GET_NODE(target, src) do {
(target)->op_type = src ## _type;
if ((target)->op_type == IS_CONST) {
(target)->u.constant = CONSTANT(src.constant);
} else {
(target)->u.op = src;
(target)->EA = 0;
}
} while (0)
static zend_uint get_temporary_variable(zend_op_array *op_array) /* {{{ */
{
return (op_array->T)++ * ZEND_MM_ALIGNED_SIZE(sizeof(temp_variable));
}
zend_op *get_next_op(zend_op_array *op_array TSRMLS_DC)
{
zend_uint next_op_num = op_array->last++;
zend_op *next_op;
if (next_op_num >= CG(context).opcodes_size) {
if (op_array->fn_flags & ZEND_ACC_INTERACTIVE) {
/* we messed up */
zend_printf("Ran out of opcode space!
"
"You should probably consider writing this huge script into a file!
");
zend_bailout();
}
CG(context).opcodes_size *= 4;
op_array_alloc_ops(op_array, CG(context).opcodes_size);
}
next_op = &(op_array->opcodes[next_op_num]);
init_op(next_op TSRMLS_CC);
return next_op;
}
void init_op(zend_op *op TSRMLS_DC)
{
memset(op, 0, sizeof(zend_op)); //初始化
op->lineno = CG(zend_lineno);
SET_UNUSED(op->result);
}
typedef struct _zend_file_handle {
zend_stream_type type;
const char *filename;
char *opened_path;
union {
int fd;
FILE *fp;
zend_stream stream;
} handle;
zend_bool free_filename;
} zend_file_handle;
void init_op_array(zend_op_array *op_array, zend_uchar type, int initial_ops_size TSRMLS_DC)
{
op_array->type = type;
if (CG(interactive)) {
/* We must avoid a realloc() on the op_array in interactive mode, since pointers to constants
* will become invalid
*/
initial_ops_size = INITIAL_INTERACTIVE_OP_ARRAY_SIZE;
}
op_array->refcount = (zend_uint *) emalloc(sizeof(zend_uint));
*op_array->refcount = 1;
op_array->last = 0;
op_array->opcodes = NULL;
op_array_alloc_ops(op_array, initial_ops_size);
op_array->last_var = 0;
op_array->vars = NULL;
op_array->T = 0;
op_array->function_name = NULL;
op_array->filename = zend_get_compiled_filename(TSRMLS_C);
op_array->doc_comment = NULL;
op_array->doc_comment_len = 0;
op_array->arg_info = NULL;
op_array->num_args = 0;
op_array->required_num_args = 0;
op_array->scope = NULL;
op_array->brk_cont_array = NULL;
op_array->try_catch_array = NULL;
op_array->last_brk_cont = 0;
op_array->static_variables = NULL;
op_array->last_try_catch = 0;
op_array->this_var = -1;
op_array->fn_flags = CG(interactive)?ZEND_ACC_INTERACTIVE:0;
op_array->early_binding = -1;
op_array->last_literal = 0;
op_array->literals = NULL;
op_array->run_time_cache = NULL;
op_array->last_cache_slot = 0;
memset(op_array->reserved, 0, ZEND_MAX_RESERVED_RESOURCES * sizeof(void*));
zend_llist_apply_with_argument(&zend_extensions, (llist_apply_with_arg_func_t) zend_extension_op_array_ctor_handler, op_array TSRMLS_CC);
}
执行 opcode
static int ZEND_FASTCALL ZEND_DO_FCALL_SPEC_CONST_HANDLER(ZEND_OPCODE_HANDLER_ARGS)
{
USE_OPLINE
zval *fname = opline->op1.zv;
zend_ptr_stack_3_push(&EG(arg_types_stack), EX(fbc), EX(object), EX(called_scope));
if (CACHED_PTR(opline->op1.literal->cache_slot)) {
EX(function_state).function = CACHED_PTR(opline->op1.literal->cache_slot);
} else if (UNEXPECTED(zend_hash_quick_find(EG(function_table), Z_STRVAL_P(fname), Z_STRLEN_P(fname)+1, Z_HASH_P(fname), (void **) &EX(function_state).function)==FAILURE)) {
//上面的zend_hash_quick_find很重要，从EG（function_table)中取出key为fname的value值，并将些值放入EX(fucntion_state)的function中
SAVE_OPLINE();
zend_error_noreturn(E_ERROR, "Call to undefined function %s()", fname->value.str.val);
} else {
CACHE_PTR(opline->op1.literal->cache_slot, EX(function_state).function); //放入原生态C数组中，因为会有第二次调用函数
}
EX(object) = NULL;
return zend_do_fcall_common_helper_SPEC(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU);
}
static int ZEND_FASTCALL zend_do_fcall_common_helper_SPEC(ZEND_OPCODE_HANDLER_ARGS)
{
USE_OPLINE
zend_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) { //php内部函数
temp_variable *ret = &EX_T(opline->result.var);
if (fbc->common.arg_info) {
zend_uint i=0;
zval **p = (zval**)EX(function_state).arguments;
ulong arg_count = opline->extended_value;
while (arg_count>0) {
zend_verify_arg_type(fbc, ++i, *(p-arg_count), 0 TSRMLS_CC);
arg_count--;
}
}
if (EXPECTED(EG(exception) == NULL)) {
MAKE_STD_ZVAL(ret->var.ptr);
ZVAL_NULL(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 (!zend_execute_internal) {
/* saves one function call if zend_execute_internal is not used */
fbc->internal_function.handler(opline->extended_value, ret->var.ptr, (fbc->common.fn_flags & ZEND_ACC_RETURN_REFERENCE) ? &ret->var.ptr : NULL, EX(object), RETURN_VALUE_USED(opline) TSRMLS_CC);
} else {
zend_execute_internal(execute_data, RETURN_VALUE_USED(opline) TSRMLS_CC);
}
if (!RETURN_VALUE_USED(opline)) {
zval_ptr_dtor(&ret->var.ptr);
}
} else if (RETURN_VALUE_USED(opline)) {
EX_T(opline->result.var).var.ptr = NULL;
}
} else if (fbc->type == ZEND_USER_FUNCTION) { //php算定义的函数
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();
}
} else {
zend_execute(EG(active_op_array) TSRMLS_CC);
}
EG(opline_ptr) = &EX(opline);
EG(active_op_array) = EX(op_array);
EG(return_value_ptr_ptr) = EX(original_return_value);
if (EG(active_symbol_table)) {
if (EG(symtable_cache_ptr)>=EG(symtable_cache_limit)) {
zend_hash_destroy(EG(active_symbol_table));
FREE_HASHTABLE(EG(active_symbol_table));
} else {
/* clean before putting into the cache, since clean
could call dtors, which could use cached hash */
zend_hash_clean(EG(active_symbol_table));
*(++EG(symtable_cache_ptr)) = EG(active_symbol_table);
}
}
EG(active_symbol_table) = EX(symbol_table);
} else { /* ZEND_OVERLOADED_FUNCTION */
MAKE_STD_ZVAL(EX_T(opline->result.var).var.ptr);
ZVAL_NULL(EX_T(opline->result.var).var.ptr);
/* Not sure what should be done here if it's a static method */
if (EXPECTED(EX(object) != NULL)) {
Z_OBJ_HT_P(EX(object))->call_method(fbc->common.function_name, opline->extended_value, EX_T(opline->result.var).var.ptr, &EX_T(opline->result.var).var.ptr, EX(object), RETURN_VALUE_USED(opline) TSRMLS_CC);
} else {
zend_error_noreturn(E_ERROR, "Cannot call overloaded function for non-object");
}
if (fbc->type == ZEND_OVERLOADED_FUNCTION_TEMPORARY) {
efree((char*)fbc->common.function_name);
}
efree(fbc);
if (!RETURN_VALUE_USED(opline)) {
zval_ptr_dtor(&EX_T(opline->result.var).var.ptr);
} else {
Z_UNSET_ISREF_P(EX_T(opline->result.var).var.ptr);
Z_SET_REFCOUNT_P(EX_T(opline->result.var).var.ptr, 1);
EX_T(opline->result.var).var.fcall_returned_reference = 0;
EX_T(opline->result.var).var.ptr_ptr = &EX_T(opline->result.var).var.ptr;
}
}
EX(function_state).function = (zend_function *) EX(op_array);
EX(function_state).arguments = NULL;
if (should_change_scope) {
if (EG(This)) {
if (UNEXPECTED(EG(exception) != NULL) && IS_CTOR_CALL(EX(called_scope))) {
if (IS_CTOR_USED(EX(called_scope))) {
Z_DELREF_P(EG(This));
}
if (Z_REFCOUNT_P(EG(This)) == 1) {
zend_object_store_ctor_failed(EG(This) TSRMLS_CC);
}
}
zval_ptr_dtor(&EG(This));
}
EG(This) = EX(current_this);
EG(scope) = EX(current_scope);
EG(called_scope) = EX(current_called_scope);
}
EX(object) = EX(current_object);
EX(called_scope) = DECODE_CTOR(EX(called_scope));
zend_vm_stack_clear_multiple(TSRMLS_C);
if (UNEXPECTED(EG(exception) != NULL)) {
zend_throw_exception_internal(NULL TSRMLS_CC);
if (RETURN_VALUE_USED(opline) && EX_T(opline->result.var).var.ptr) {
zval_ptr_dtor(&EX_T(opline->result.var).var.ptr);
}
HANDLE_EXCEPTION();
}
ZEND_VM_NEXT_OPCODE();
}
void init_executor(TSRMLS_D) /* {{{ */
{
zend_init_fpu(TSRMLS_C);
INIT_ZVAL(EG(uninitialized_zval));
/* trick to make uninitialized_zval never be modified, passed by ref, etc. */
Z_ADDREF(EG(uninitialized_zval));
INIT_ZVAL(EG(error_zval));
EG(uninitialized_zval_ptr)=&EG(uninitialized_zval);
EG(error_zval_ptr)=&EG(error_zval);
zend_ptr_stack_init(&EG(arg_types_stack));
/* destroys stack frame, therefore makes core dumps worthless */
#if 0&&ZEND_DEBUG
original_sigsegv_handler = signal(SIGSEGV, zend_handle_sigsegv);
#endif
EG(return_value_ptr_ptr) = NULL;
EG(symtable_cache_ptr) = EG(symtable_cache) - 1;
EG(symtable_cache_limit) = EG(symtable_cache) + SYMTABLE_CACHE_SIZE - 1;
EG(no_extensions) = 0;
EG(function_table) = CG(function_table); //很重要
EG(class_table) = CG(class_table);
EG(in_execution) = 0;
EG(in_autoload) = NULL;
EG(autoload_func) = NULL;
EG(error_handling) = EH_NORMAL;
zend_vm_stack_init(TSRMLS_C);
zend_vm_stack_push((void *) NULL TSRMLS_CC);
zend_hash_init(&EG(symbol_table), 50, NULL, ZVAL_PTR_DTOR, 0);
EG(active_symbol_table) = &EG(symbol_table);
zend_llist_apply(&zend_extensions, (llist_apply_func_t) zend_extension_activator TSRMLS_CC);
EG(opline_ptr) = NULL;
zend_hash_init(&EG(included_files), 5, NULL, NULL, 0);
EG(ticks_count) = 0;
EG(user_error_handler) = NULL;
EG(current_execute_data) = NULL;
zend_stack_init(&EG(user_error_handlers_error_reporting));
zend_ptr_stack_init(&EG(user_error_handlers));
zend_ptr_stack_init(&EG(user_exception_handlers));
zend_objects_store_init(&EG(objects_store), 1024);
EG(full_tables_cleanup) = 0;
#ifdef ZEND_WIN32
EG(timed_out) = 0;
#endif
EG(exception) = NULL;
EG(prev_exception) = NULL;
EG(scope) = NULL;
EG(called_scope) = NULL;
EG(This) = NULL;
EG(active_op_array) = NULL;
EG(active) = 1;
EG(start_op) = NULL;
}
struct _zend_vm_stack {
void **top;
void **end;
zend_vm_stack prev;
};
static zend_always_inline void zend_vm_stack_push(void *ptr TSRMLS_DC)
{
ZEND_VM_STACK_GROW_IF_NEEDED(1);
*(EG(argument_stack)->top++) = ptr;
}
http://www.cnblogs.com/driftcloudy/p/3213504.html
函数传递参数入栈的原理
http://www.laruence.com/2010/01/03/1225.html
http://blog.sina.com.cn/s/blog_6ecf35840100m669.html 传值，传引用
http://www.phppan.com/2012/04/php-compiled-variable/ cv
本文主要参考“风雪之域”Laruence的文章。转载：http://www.laruence.com/2008/04/01/116.html
我们刚学php的时候，学到函数时，常会向里面传参数。比如function example($a,$b).那到底a和b的参数是怎么传入到example函数以及函数是怎么接受的呢，下面来为大家揭秘。
在 Zend/zend_language_scanner.l中我们会找到如下所示的代码：
<ST_IN_SCRipTING>
"function" {
return T_FUNCTION;
}
它所表示的含义是function将会生成T_FUNCTION标记。T_FUNCTION标记只是用来定义函数的生命，标明这是一个函数，更多的东西则是参数，返回值等等。
当php等高级语言被编译成机器码时面临一个问题，cpu不能识别函数怎么传参，传的几个参数，传递参数的工作必须由函数调用者或函数本书来完成。当函数调用时，调用者依次把参数压栈，然后调用函数，调用后，在堆栈中取得数据，并进行计算。函数计算完成后，由调用者或者函数本身修改堆栈，使堆栈恢复原状。在参数传递过程中，有下列三个问题需要注意：
1：参数多余一个时，传递参数的顺序
2：函数调用后，谁来恢复堆栈
3：函数的返回值放在什么地方。
在高级语言中，通过函数调用规范来说明这几个问题。常见的调用规范有下面几个：
stdcall、cdecl、fastcall、thiscall、naked call
具体的调用规范大家可以参考具体的例子，这里只是把这几个问题的答案说出来
1：传递参数是由后到前传递。function example($a,$b).中，先把$b压栈再把$a压栈
2：由相关的规范决定