Nikita Popov
653e4ea1c5
While performing resource -> object migrations, we're adding defensive classes that are final, non-serializable and non-clonable (unless they are, of course). This path adds a ZEND_ACC_NO_DYNAMIC_PROPERTIES flag, that also forbids the creation of dynamic properties on these objects. This is a subset of #3931 and targeted at internal usage only (though may be extended to userland at some point in the future). It's already possible to achieve this (what the removed WeakRef/WeakMap code does), but there's some caveats: First, this simple approach is only possible if the class has no declared properties, otherwise it's necessary to special-case those properties. Second, it's easy to make it overly strict, e.g. by forbidding isset($obj->prop) as well. And finally, it requires a lot of boilerplate code for each class. Closes GH-5572.
Zend Engine
Zend memory manager
General
The goal of the new memory manager (available since PHP 5.2) is to reduce memory allocation overhead and speedup memory management.
Debugging
Normal:
sapi/cli/php -r 'leak();'
Zend MM disabled:
USE_ZEND_ALLOC=0 valgrind --leak-check=full sapi/cli/php -r 'leak();'
Shared extensions
Since PHP 5.3.11 it is possible to prevent shared extensions from unloading so
that valgrind can correctly track the memory leaks in shared extensions. For
this there is the ZEND_DONT_UNLOAD_MODULES environment variable. If set, then
DL_UNLOAD() is skipped during the shutdown of shared extensions.
ZEND_VM
ZEND_VM architecture allows specializing opcode handlers according to
op_type fields and using different execution methods (call threading, switch
threading and direct threading). As a result ZE2 got more than 20% speedup on
raw PHP code execution (with specialized executor and direct threading execution
method). As in most PHP applications raw execution speed isn't the limiting
factor but system calls and database calls are, your mileage with this patch
will vary.
Most parts of the old zend_execute.c go into zend_vm_def.h. Here you can find
opcode handlers and helpers. The typical opcode handler template looks like
this:
ZEND_VM_HANDLER(<OPCODE-NUMBER>, <OPCODE>, <OP1_TYPES>, <OP2_TYPES>)
{
<HANDLER'S CODE>
}
<OPCODE-NUMBER> is a opcode number (0, 1, ...)
<OPCODE> is an opcode name (ZEN_NOP, ZEND_ADD, :)
<OP1_TYPES> and <OP2_TYPES> are masks for allowed operand op_types.
Specializer will generate code only for defined combination of types. You can
use any combination of the following op_types UNUSED, CONST, VAR, TMP and CV
also you can use ANY mask to disable specialization according operand's op_type.
<HANDLER'S CODE> is a handler's code itself. For most handlers it stills the
same as in old zend_execute.c, but now it uses macros to access opcode
operands and some internal executor data.
You can see the conformity of new macros to old code in the following list:
EXECUTE_DATA
execute_data
ZEND_VM_DISPATCH_TO_HANDLER(<OP>)
return <OP>_helper(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU)
ZEND_VM_DISPATCH_TO_HELPER(<NAME>)
return <NAME>(ZEND_OPCODE_HANDLER_ARGS_PASSTHRU)
ZEND_VM_DISPATCH_TO_HELPER_EX(<NAME>,<PARAM>,<VAL>)
return <NAME>(<VAL>, ZEND_OPCODE_HANDLER_ARGS_PASSTHRU)
ZEND_VM_CONTINUE()
return 0
ZEND_VM_NEXT_OPCODE()
NEXT_OPCODE()
ZEND_VM_SET_OPCODE(<TARGET>
SET_OPCODE(<TARGET>
ZEND_VM_INC_OPCODE()
INC_OPCOD()
ZEND_VM_RETURN_FROM_EXECUTE_LOOP()
RETURN_FROM_EXECUTE_LOOP()
ZEND_VM_C_LABEL(<LABEL>):
<LABEL>:
ZEND_VM_C_GOTO(<LABEL>)
goto <LABEL>
OP<X>_TYPE
opline->op<X>.op_type
GET_OP<X>_ZVAL_PTR(<TYPE>)
get_zval_ptr(&opline->op<X>, EX(Ts), &free_op<X>, <TYPE>)
GET_OP<X>_ZVAL_PTR_PTR(<TYPE>)
get_zval_ptr_ptr(&opline->op<X>, EX(Ts), &free_op<X>, <TYPE>)
GET_OP<X>_OBJ_ZVAL_PTR(<TYPE>)
get_obj_zval_ptr(&opline->op<X>, EX(Ts), &free_op<X>, <TYPE>)
GET_OP<X>_OBJ_ZVAL_PTR_PTR(<TYPE>)
get_obj_zval_ptr_ptr(&opline->op<X>, EX(Ts), &free_op<X>, <TYPE>)
IS_OP<X>_TMP_FREE()
IS_TMP_FREE(free_op<X>)
FREE_OP<X>()
FREE_OP(free_op<X>)
FREE_OP<X>_IF_VAR()
FREE_VAR(free_op<X>)
FREE_OP<X>_VAR_PTR()
FREE_VAR_PTR(free_op<X>)
Executor's helpers can be defined without parameters or with one parameter. This is done with the following constructs:
ZEND_VM_HELPER(<HELPER-NAME>, <OP1_TYPES>, <OP2_TYPES>)
{
<HELPER'S CODE>
}
ZEND_VM_HELPER_EX(<HELPER-NAME>, <OP1_TYPES>, <OP2_TYPES>, <PARAM_SPEC>)
{
<HELPER'S CODE>
}
Executor's code is generated by PHP script zend_vm_gen.php it uses
zend_vm_def.h and zend_vm_execute.skl as input and produces
zend_vm_opcodes.h and zend_vm_execute.h. The first file is a list of opcode
definitions. It is included from zend_compile.h. The second one is an executor
code itself. It is included from zend_execute.c.
zend_vm_gen.php can produce different kind of executors. You can select
different opcode threading model using --with-vm-kind=CALL|SWITCH|GOTO. You
can disable opcode specialization using --without-specializer. You can include
or exclude old executor together with specialized one using
--without-old-executor. At last you can debug executor using original
zend_vm_def.h or generated file zend_vm_execute.h. Debugging with original
file requires --with-lines option. By default ZE2 uses the following command
to generate executor:
php zend_vm_gen.php --with-vm-kind=CALL