Hello internals,
Hello Andi,
here's another major speed improvement for array functions which
is probably also valid for other functions, too. The point is that
we have several functions not forcing parameters by reference because
they not only accept variables but also parameters by value and we
cannot pass values by ref directly. The solution is to automatically
find out whether to pass by ref or not. See the test script for
the difference - it's amazing in this example!
http://php.net/~helly/php/ext/ze2/ze2-auto-ref-20040930.diff.txt
http://php.net/~helly/php/ext/ze2/ze2-auto-ref.php
How does it work exactly:
For example the function in_array() is defined with both arg types == 0
which mean not by ref. As a consequence when you have an array which is
stored somewhere else as a reference it will be copied. So the obvious
question is why not declare the function arg type as force by reference?
Simply because that does not work. The array functions are all designed
to accept arrays on the fly like in_array(2,array(1,2)). And unfortunatley
those direct values cannot be send by reference. But the compiler knows
whether it can send by ref or not and that is what the patch does. It
adds a new argument infor which tells the compiler to find out whether
the parameter can be passed by reference or must be passed by value.
Any comments?
--
Best regards,
Marcus
Marcus,
From reading this it doesn't seem as if this patch is array() specific but
is a general one.
If I understand correctly, it will pass the hash (zval *) as-is and will
never do a zval_copy_ctor(). This means that this value must for all
practical purposes be read-only. What does this mean to the extension writer?
Am I correct? We need to be sure that we don't add this new functionality
without being sure how the extensions should handle it in order not to get
side effects.
Andi
At 12:20 PM 10/2/2004 +0200, Marcus Boerger wrote:
Hello internals,
Hello Andi,
here's another major speed improvement for array functions which
is probably also valid for other functions, too. The point is that
we have several functions not forcing parameters by reference because
they not only accept variables but also parameters by value and we
cannot pass values by ref directly. The solution is to automatically
find out whether to pass by ref or not. See the test script for
the difference - it's amazing in this example!http://php.net/~helly/php/ext/ze2/ze2-auto-ref-20040930.diff.txt
http://php.net/~helly/php/ext/ze2/ze2-auto-ref.phpHow does it work exactly:
For example the function
in_array()is defined with both arg types == 0
which mean not by ref. As a consequence when you have an array which is
stored somewhere else as a reference it will be copied. So the obvious
question is why not declare the function arg type as force by reference?
Simply because that does not work. The array functions are all designed
to accept arrays on the fly like in_array(2,array(1,2)). And unfortunatley
those direct values cannot be send by reference. But the compiler knows
whether it can send by ref or not and that is what the patch does. It
adds a new argument infor which tells the compiler to find out whether
the parameter can be passed by reference or must be passed by value.Any comments?
--
Best regards,
Marcus
Hello Andi,
Tuesday, October 5, 2004, 3:06:57 AM, you wrote:
Marcus,
From reading this it doesn't seem as if this patch is array() specific but
is a general one.
Yes it is a general one applicable to any function handling zvals with
greater data than the zval itself (array, string, maybe objects in ze1
compat mode).
If I understand correctly, it will pass the hash (zval *) as-is and will
never do a zval_copy_ctor(). This means that this value must for all
practical purposes be read-only. What does this mean to the extension writer?
Am I correct? We need to be sure that we don't add this new functionality
without being sure how the extensions should handle it in order not to get
side effects.
The extension writer must only use this arg-info flag if he is sure the
variables are not touched inside the function. It behaves exactly like
force by reference as long as you pass variables. Though the latter is
most often used to modify parameters by design. So the extension writer
should take care whether to use it.
regards
marcus
At 12:20 PM 10/2/2004 +0200, Marcus Boerger wrote:
Hello internals,
Hello Andi,
here's another major speed improvement for array functions which
is probably also valid for other functions, too. The point is that
we have several functions not forcing parameters by reference because
they not only accept variables but also parameters by value and we
cannot pass values by ref directly. The solution is to automatically
find out whether to pass by ref or not. See the test script for
the difference - it's amazing in this example!http://php.net/~helly/php/ext/ze2/ze2-auto-ref-20040930.diff.txt
http://php.net/~helly/php/ext/ze2/ze2-auto-ref.phpHow does it work exactly:
For example the function
in_array()is defined with both arg types == 0
which mean not by ref. As a consequence when you have an array which is
stored somewhere else as a reference it will be copied. So the obvious
question is why not declare the function arg type as force by reference?
Simply because that does not work. The array functions are all designed
to accept arrays on the fly like in_array(2,array(1,2)). And unfortunatley
those direct values cannot be send by reference. But the compiler knows
whether it can send by ref or not and that is what the patch does. It
adds a new argument infor which tells the compiler to find out whether
the parameter can be passed by reference or must be passed by value.