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[PHP-DEV] Inconsistency in line numbers.

Posted by Derick Rethans 
Derick Rethans
[PHP-DEV] Inconsistency in line numbers.
April 15, 2017 05:30PM
Hi Nikita,

Through Xdebug bug #1413 (https://bugs.xdebug.org/view.php?id=1413), I noticed
that behaviour with class constants changed between PHP 7.1.3 and PHP 7.1.4.
I *believe* it is because of the fix for issue #69676
(https://bugs.php.net/bug.php?id=69676) that got fixed in PHP 7.1.4.

With OPcache loaded, the INIT_ARRAY and further opcodes are relisted as being
on line 15 instead of line 17. Although, I would probably argue that
INIT_ARRAY should really be on line 13 (the opening [).

Without OPcache loaded, in PHP 7.1.3, FETCH_CLASS_CONSTANT is on line 15, and
the INIT_ARRAY and further opcodes are on line 17. In PHP 7.1.4, they are all
on line 15 - with 17 no longer showing up.

I believe, the behaviour with and without OPcache should be the same, and I
would argue that the correct result would need to be that FETCH_CLASS_CONSTANT
(if still present, OPcache optimises it out) should be on line 15, the
INIT_ARRAY on line 13, and the SEND_VAL_EX and further, are on line 17.

Code
====

1 <?php
2
3 namespace ICanBoogie\Validate\Validator;
4
5 class Required2
6 {
7 const ALIAS = 'required';
8 const DEFAULT_MESSAGE = "is required";
9 const OPTION_STOP_ON_ERROR = 'stop_on_error';
10
11 public function normalize_params(array $params)
12 {
13 return array_merge([
14
15 self::OPTION_STOP_ON_ERROR => true
16
17 ], $params);
18 }
19 }


PHP 7.1.3 (no OPcache)
======================

filename: /tmp/xdebug-bug-1/lib/Required2.php
function name: normalize_params
number of ops: 14
compiled vars: !0 = $params
line #* E I O op fetch ext return operands
-------------------------------------------------------------------------------------
11 0 E > EXT_NOP
1 RECV !0
13 2 EXT_STMT
3 INIT_NS_FCALL_BY_NAME
4 EXT_FCALL_BEGIN
15 5 FETCH_CLASS_CONSTANT ~1 'OPTION_STOP_ON_ERROR'
17 6 INIT_ARRAY ~2 <true>, ~1
7 SEND_VAL_EX ~2
8 SEND_VAR_EX !0
9 DO_FCALL_BY_NAME
10 EXT_FCALL_END
11 > RETURN $3
18 12* EXT_STMT
13* > RETURN null


PHP 7.1.3 (OPcache)
======================

filename: /tmp/xdebug-bug-1/lib/Required2.php
function name: normalize_params
number of ops: 11
compiled vars: !0 = $params
line #* E I O op fetch ext return operands
-------------------------------------------------------------------------------------
11 0 E > EXT_NOP
1 RECV !0
13 2 EXT_STMT
3 INIT_NS_FCALL_BY_NAME
4 EXT_FCALL_BEGIN
17 5 INIT_ARRAY ~1 <true>, 'stop_on_error'
6 SEND_VAL_EX ~1
7 SEND_VAR_EX !0
8 DO_FCALL 0 $1
9 EXT_FCALL_END
10 > RETURN $1


PHP 7.1.4 (no OPcache)
======================

filename: /tmp/xdebug-bug-1/lib/Required2.php
function name: normalize_params
number of ops: 14
compiled vars: !0 = $params
line #* E I O op fetch ext return operands
-------------------------------------------------------------------------------------
11 0 E > EXT_NOP
1 RECV !0
13 2 EXT_STMT
3 INIT_NS_FCALL_BY_NAME
4 EXT_FCALL_BEGIN
15 5 FETCH_CLASS_CONSTANT ~1 'OPTION_STOP_ON_ERROR'
6 INIT_ARRAY ~2 <true>, ~1
7 SEND_VAL_EX ~2
8 SEND_VAR_EX !0
9 DO_FCALL_BY_NAME
10 EXT_FCALL_END
11 > RETURN $3
18 12* EXT_STMT
13* > RETURN null


PHP 7.1.4 (OPcache)
======================

filename: /tmp/xdebug-bug-1/lib/Required2.php
function name: normalize_params
number of ops: 11
compiled vars: !0 = $params
line #* E I O op fetch ext return operands
-------------------------------------------------------------------------------------
11 0 E > EXT_NOP
1 RECV !0
13 2 EXT_STMT
3 INIT_NS_FCALL_BY_NAME
4 EXT_FCALL_BEGIN
15 5 INIT_ARRAY ~1 <true>, 'stop_on_error'
6 SEND_VAL_EX ~1
7 SEND_VAR_EX !0
8 DO_FCALL 0 $1
9 EXT_FCALL_END
10 > RETURN $1

cheers,
Derick


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Nikita Popov
[PHP-DEV] Re: Inconsistency in line numbers.
April 15, 2017 06:30PM
On Sat, Apr 15, 2017 at 5:25 PM, Derick Rethans <[email protected]> wrote:

> Hi Nikita,
>
> Through Xdebug bug #1413 (https://bugs.xdebug.org/view.php?id=1413), I
> noticed
> that behaviour with class constants changed between PHP 7.1.3 and PHP
> 7.1.4.
> I *believe* it is because of the fix for issue #69676
> (https://bugs.php.net/bug.php?id=69676) that got fixed in PHP 7.1.4.
>
> With OPcache loaded, the INIT_ARRAY and further opcodes are relisted as
> being
> on line 15 instead of line 17. Although, I would probably argue that
> INIT_ARRAY should really be on line 13 (the opening [).
>
> Without OPcache loaded, in PHP 7.1.3, FETCH_CLASS_CONSTANT is on line 15,
> and
> the INIT_ARRAY and further opcodes are on line 17. In PHP 7.1.4, they are
> all
> on line 15 - with 17 no longer showing up.
>
> I believe, the behaviour with and without OPcache should be the same, and I
> would argue that the correct result would need to be that
> FETCH_CLASS_CONSTANT
> (if still present, OPcache optimises it out) should be on line 15, the
> INIT_ARRAY on line 13, and the SEND_VAL_EX and further, are on line 17.
>
> Code
> ====
>
> 1 <?php
> 2
> 3 namespace ICanBoogie\Validate\Validator;
> 4
> 5 class Required2
> 6 {
> 7 const ALIAS = 'required';
> 8 const DEFAULT_MESSAGE = "is required";
> 9 const OPTION_STOP_ON_ERROR = 'stop_on_error';
> 10
> 11 public function normalize_params(array $params)
> 12 {
> 13 return array_merge([
> 14
> 15 self::OPTION_STOP_ON_ERROR => true
> 16
> 17 ], $params);
> 18 }
> 19 }
>
>
> PHP 7.1.3 (no OPcache)
> ======================
>
> filename: /tmp/xdebug-bug-1/lib/Required2.php
> function name: normalize_params
> number of ops: 14
> compiled vars: !0 = $params
> line #* E I O op fetch ext return
> operands
> ------------------------------------------------------------
> -------------------------
> 11 0 E > EXT_NOP
> 1 RECV !0
> 13 2 EXT_STMT
> 3 INIT_NS_FCALL_BY_NAME
> 4 EXT_FCALL_BEGIN
> 15 5 FETCH_CLASS_CONSTANT ~1
> 'OPTION_STOP_ON_ERROR'
> 17 6 INIT_ARRAY ~2
> <true>, ~1
> 7 SEND_VAL_EX
> ~2
> 8 SEND_VAR_EX
> !0
> 9 DO_FCALL_BY_NAME
> 10 EXT_FCALL_END
> 11 > RETURN
> $3
> 18 12* EXT_STMT
> 13* > RETURN
> null
>
>
> PHP 7.1.3 (OPcache)
> ======================
>
> filename: /tmp/xdebug-bug-1/lib/Required2.php
> function name: normalize_params
> number of ops: 11
> compiled vars: !0 = $params
> line #* E I O op fetch ext return
> operands
> ------------------------------------------------------------
> -------------------------
> 11 0 E > EXT_NOP
> 1 RECV !0
> 13 2 EXT_STMT
> 3 INIT_NS_FCALL_BY_NAME
> 4 EXT_FCALL_BEGIN
> 17 5 INIT_ARRAY ~1
> <true>, 'stop_on_error'
> 6 SEND_VAL_EX
> ~1
> 7 SEND_VAR_EX
> !0
> 8 DO_FCALL 0 $1
> 9 EXT_FCALL_END
> 10 > RETURN
> $1
>
>
> PHP 7.1.4 (no OPcache)
> ======================
>
> filename: /tmp/xdebug-bug-1/lib/Required2.php
> function name: normalize_params
> number of ops: 14
> compiled vars: !0 = $params
> line #* E I O op fetch ext return
> operands
> ------------------------------------------------------------
> -------------------------
> 11 0 E > EXT_NOP
> 1 RECV !0
> 13 2 EXT_STMT
> 3 INIT_NS_FCALL_BY_NAME
> 4 EXT_FCALL_BEGIN
> 15 5 FETCH_CLASS_CONSTANT ~1
> 'OPTION_STOP_ON_ERROR'
> 6 INIT_ARRAY ~2
> <true>, ~1
> 7 SEND_VAL_EX
> ~2
> 8 SEND_VAR_EX
> !0
> 9 DO_FCALL_BY_NAME
> 10 EXT_FCALL_END
> 11 > RETURN
> $3
> 18 12* EXT_STMT
> 13* > RETURN
> null
>
>
> PHP 7.1.4 (OPcache)
> ======================
>
> filename: /tmp/xdebug-bug-1/lib/Required2.php
> function name: normalize_params
> number of ops: 11
> compiled vars: !0 = $params
> line #* E I O op fetch ext return
> operands
> ------------------------------------------------------------
> -------------------------
> 11 0 E > EXT_NOP
> 1 RECV !0
> 13 2 EXT_STMT
> 3 INIT_NS_FCALL_BY_NAME
> 4 EXT_FCALL_BEGIN
> 15 5 INIT_ARRAY ~1
> <true>, 'stop_on_error'
> 6 SEND_VAL_EX
> ~1
> 7 SEND_VAR_EX
> !0
> 8 DO_FCALL 0 $1
> 9 EXT_FCALL_END
> 10 > RETURN
> $1
>
> cheers,
> Derick
>

This is due to
https://github.com/php/php-src/commit/183cd048f18fa4b04fb30448a84a54cee80a2491,
which fixed lineno assignment for list AST nodes. This changed the start
lineno of the array from line 17 (the end of the array) to line 15 (the
first array element). Of course this is still inaccurate (the actual start
line is 13), but it's the closest we can get with the information we
currently have available.

The problem in this case is that the second SEND_VAR_EX did not bump the
lineno. I've fixed this in
https://github.com/php/php-src/commit/e433c23b96e81340cd0e2d0b4b7f5fce7f72a931
..

This required a change to an existing test, which alerted me to some weird
behavior I wasn't aware of: https://3v4l.org/6fSRb In backtraces the call
is located on the line of it's last argument (in PHP 5.6 the line of the
closing ")"). Wouldn't it make more sense to use the starting line of the
call? That is, use the same lineno for INIT_FCALL and DO_FCALL?

Nikita
Derick Rethans
[PHP-DEV] Re: Inconsistency in line numbers.
April 15, 2017 09:20PM
On April 15, 2017 5:24:53 PM GMT+01:00, Nikita Popov <[email protected]> wrote:
>On Sat, Apr 15, 2017 at 5:25 PM, Derick Rethans <[email protected]> wrote:
>
>> Hi Nikita,
>>
>> Through Xdebug bug #1413 (https://bugs.xdebug.org/view.php?id=1413),
>I
>> noticed
>> that behaviour with class constants changed between PHP 7.1.3 and PHP
>> 7.1.4.
>> I *believe* it is because of the fix for issue #69676
>> (https://bugs.php.net/bug.php?id=69676) that got fixed in PHP 7.1.4.
>>
>> With OPcache loaded, the INIT_ARRAY and further opcodes are relisted
>as
>> being
>> on line 15 instead of line 17. Although, I would probably argue that
>> INIT_ARRAY should really be on line 13 (the opening [).
>>
>> Without OPcache loaded, in PHP 7.1.3, FETCH_CLASS_CONSTANT is on line
>15,
>> and
>> the INIT_ARRAY and further opcodes are on line 17. In PHP 7.1.4, they
>are
>> all
>> on line 15 - with 17 no longer showing up.
>>
>> I believe, the behaviour with and without OPcache should be the same,
>and I
>> would argue that the correct result would need to be that
>> FETCH_CLASS_CONSTANT
>> (if still present, OPcache optimises it out) should be on line 15,
>the
>> INIT_ARRAY on line 13, and the SEND_VAL_EX and further, are on line
>17.
>>
>> Code
>> ====
>>
>> 1 <?php
>> 2
>> 3 namespace ICanBoogie\Validate\Validator;
>> 4
>> 5 class Required2
>> 6 {
>> 7 const ALIAS = 'required';
>> 8 const DEFAULT_MESSAGE = "is required";
>> 9 const OPTION_STOP_ON_ERROR = 'stop_on_error';
>> 10
>> 11 public function normalize_params(array $params)
>> 12 {
>> 13 return array_merge([
>> 14
>> 15 self::OPTION_STOP_ON_ERROR => true
>> 16
>> 17 ], $params);
>> 18 }
>> 19 }
>>
>>
>> PHP 7.1.3 (no OPcache)
>> ======================
>>
>> filename: /tmp/xdebug-bug-1/lib/Required2.php
>> function name: normalize_params
>> number of ops: 14
>> compiled vars: !0 = $params
>> line #* E I O op fetch ext
>return
>> operands
>> ------------------------------------------------------------
>> -------------------------
>> 11 0 E > EXT_NOP
>> 1 RECV !0
>> 13 2 EXT_STMT
>> 3 INIT_NS_FCALL_BY_NAME
>> 4 EXT_FCALL_BEGIN
>> 15 5 FETCH_CLASS_CONSTANT ~1
>> 'OPTION_STOP_ON_ERROR'
>> 17 6 INIT_ARRAY ~2
>> <true>, ~1
>> 7 SEND_VAL_EX
>> ~2
>> 8 SEND_VAR_EX
>> !0
>> 9 DO_FCALL_BY_NAME
>> 10 EXT_FCALL_END
>> 11 > RETURN
>> $3
>> 18 12* EXT_STMT
>> 13* > RETURN
>> null
>>
>>
>> PHP 7.1.3 (OPcache)
>> ======================
>>
>> filename: /tmp/xdebug-bug-1/lib/Required2.php
>> function name: normalize_params
>> number of ops: 11
>> compiled vars: !0 = $params
>> line #* E I O op fetch ext
>return
>> operands
>> ------------------------------------------------------------
>> -------------------------
>> 11 0 E > EXT_NOP
>> 1 RECV !0
>> 13 2 EXT_STMT
>> 3 INIT_NS_FCALL_BY_NAME
>> 4 EXT_FCALL_BEGIN
>> 17 5 INIT_ARRAY ~1
>> <true>, 'stop_on_error'
>> 6 SEND_VAL_EX
>> ~1
>> 7 SEND_VAR_EX
>> !0
>> 8 DO_FCALL 0 $1
>> 9 EXT_FCALL_END
>> 10 > RETURN
>> $1
>>
>>
>> PHP 7.1.4 (no OPcache)
>> ======================
>>
>> filename: /tmp/xdebug-bug-1/lib/Required2.php
>> function name: normalize_params
>> number of ops: 14
>> compiled vars: !0 = $params
>> line #* E I O op fetch ext
>return
>> operands
>> ------------------------------------------------------------
>> -------------------------
>> 11 0 E > EXT_NOP
>> 1 RECV !0
>> 13 2 EXT_STMT
>> 3 INIT_NS_FCALL_BY_NAME
>> 4 EXT_FCALL_BEGIN
>> 15 5 FETCH_CLASS_CONSTANT ~1
>> 'OPTION_STOP_ON_ERROR'
>> 6 INIT_ARRAY ~2
>> <true>, ~1
>> 7 SEND_VAL_EX
>> ~2
>> 8 SEND_VAR_EX
>> !0
>> 9 DO_FCALL_BY_NAME
>> 10 EXT_FCALL_END
>> 11 > RETURN
>> $3
>> 18 12* EXT_STMT
>> 13* > RETURN
>> null
>>
>>
>> PHP 7.1.4 (OPcache)
>> ======================
>>
>> filename: /tmp/xdebug-bug-1/lib/Required2.php
>> function name: normalize_params
>> number of ops: 11
>> compiled vars: !0 = $params
>> line #* E I O op fetch ext
>return
>> operands
>> ------------------------------------------------------------
>> -------------------------
>> 11 0 E > EXT_NOP
>> 1 RECV !0
>> 13 2 EXT_STMT
>> 3 INIT_NS_FCALL_BY_NAME
>> 4 EXT_FCALL_BEGIN
>> 15 5 INIT_ARRAY ~1
>> <true>, 'stop_on_error'
>> 6 SEND_VAL_EX
>> ~1
>> 7 SEND_VAR_EX
>> !0
>> 8 DO_FCALL 0 $1
>> 9 EXT_FCALL_END
>> 10 > RETURN
>> $1
>>
>> cheers,
>> Derick
>>
>
>This is due to
>https://github.com/php/php-src/commit/183cd048f18fa4b04fb30448a84a54cee80a2491,
>which fixed lineno assignment for list AST nodes. This changed the
>start
>lineno of the array from line 17 (the end of the array) to line 15 (the
>first array element). Of course this is still inaccurate (the actual
>start
>line is 13), but it's the closest we can get with the information we
>currently have available.
>
>The problem in this case is that the second SEND_VAR_EX did not bump
>the
>lineno. I've fixed this in
>https://github.com/php/php-src/commit/e433c23b96e81340cd0e2d0b4b7f5fce7f72a931
>.
>
>This required a change to an existing test, which alerted me to some
>weird
>behavior I wasn't aware of: https://3v4l.org/6fSRb In backtraces the
>call
>is located on the line of it's last argument (in PHP 5.6 the line of
>the
>closing ")"). Wouldn't it make more sense to use the starting line of
>the
>call? That is, use the same lineno for INIT_FCALL and DO_FCALL?
>
>Nikita

It makes sense to me to use the first line, as long as further opcodes will have the right line number.

Selfishly, I'd prefer if that change was only made for master, due to the increasingly complex tests I need to make for Xdebug's code coverage.

cheers,
Derick

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Levi Morrison
Re: [PHP-DEV] Re: Inconsistency in line numbers.
April 15, 2017 11:20PM
On Sat, Apr 15, 2017 at 1:13 PM, Derick Rethans <[email protected]> wrote:

> On April 15, 2017 5:24:53 PM GMT+01:00, Nikita Popov <[email protected]>
> wrote:
> >On Sat, Apr 15, 2017 at 5:25 PM, Derick Rethans <[email protected]> wrote:
> >
> >> Hi Nikita,
> >>
> >> Through Xdebug bug #1413 (https://bugs.xdebug.org/view.php?id=1413),
> >I
> >> noticed
> >> that behaviour with class constants changed between PHP 7.1.3 and PHP
> >> 7.1.4.
> >> I *believe* it is because of the fix for issue #69676
> >> (https://bugs.php.net/bug.php?id=69676) that got fixed in PHP 7.1.4.
> >>
> >> With OPcache loaded, the INIT_ARRAY and further opcodes are relisted
> >as
> >> being
> >> on line 15 instead of line 17. Although, I would probably argue that
> >> INIT_ARRAY should really be on line 13 (the opening [).
> >>
> >> Without OPcache loaded, in PHP 7.1.3, FETCH_CLASS_CONSTANT is on line
> >15,
> >> and
> >> the INIT_ARRAY and further opcodes are on line 17. In PHP 7.1.4, they
> >are
> >> all
> >> on line 15 - with 17 no longer showing up.
> >>
> >> I believe, the behaviour with and without OPcache should be the same,
> >and I
> >> would argue that the correct result would need to be that
> >> FETCH_CLASS_CONSTANT
> >> (if still present, OPcache optimises it out) should be on line 15,
> >the
> >> INIT_ARRAY on line 13, and the SEND_VAL_EX and further, are on line
> >17.
> >>
> >> Code
> >> ====
> >>
> >> 1 <?php
> >> 2
> >> 3 namespace ICanBoogie\Validate\Validator;
> >> 4
> >> 5 class Required2
> >> 6 {
> >> 7 const ALIAS = 'required';
> >> 8 const DEFAULT_MESSAGE = "is required";
> >> 9 const OPTION_STOP_ON_ERROR = 'stop_on_error';
> >> 10
> >> 11 public function normalize_params(array $params)
> >> 12 {
> >> 13 return array_merge([
> >> 14
> >> 15 self::OPTION_STOP_ON_ERROR => true
> >> 16
> >> 17 ], $params);
> >> 18 }
> >> 19 }
> >>
> >>
> >> PHP 7.1.3 (no OPcache)
> >> ======================
> >>
> >> filename: /tmp/xdebug-bug-1/lib/Required2.php
> >> function name: normalize_params
> >> number of ops: 14
> >> compiled vars: !0 = $params
> >> line #* E I O op fetch ext
> >return
> >> operands
> >> ------------------------------------------------------------
> >> -------------------------
> >> 11 0 E > EXT_NOP
> >> 1 RECV !0
> >> 13 2 EXT_STMT
> >> 3 INIT_NS_FCALL_BY_NAME
> >> 4 EXT_FCALL_BEGIN
> >> 15 5 FETCH_CLASS_CONSTANT ~1
> >> 'OPTION_STOP_ON_ERROR'
> >> 17 6 INIT_ARRAY ~2
> >> <true>, ~1
> >> 7 SEND_VAL_EX
> >> ~2
> >> 8 SEND_VAR_EX
> >> !0
> >> 9 DO_FCALL_BY_NAME
> >> 10 EXT_FCALL_END
> >> 11 > RETURN
> >> $3
> >> 18 12* EXT_STMT
> >> 13* > RETURN
> >> null
> >>
> >>
> >> PHP 7.1.3 (OPcache)
> >> ======================
> >>
> >> filename: /tmp/xdebug-bug-1/lib/Required2.php
> >> function name: normalize_params
> >> number of ops: 11
> >> compiled vars: !0 = $params
> >> line #* E I O op fetch ext
> >return
> >> operands
> >> ------------------------------------------------------------
> >> -------------------------
> >> 11 0 E > EXT_NOP
> >> 1 RECV !0
> >> 13 2 EXT_STMT
> >> 3 INIT_NS_FCALL_BY_NAME
> >> 4 EXT_FCALL_BEGIN
> >> 17 5 INIT_ARRAY ~1
> >> <true>, 'stop_on_error'
> >> 6 SEND_VAL_EX
> >> ~1
> >> 7 SEND_VAR_EX
> >> !0
> >> 8 DO_FCALL 0 $1
> >> 9 EXT_FCALL_END
> >> 10 > RETURN
> >> $1
> >>
> >>
> >> PHP 7.1.4 (no OPcache)
> >> ======================
> >>
> >> filename: /tmp/xdebug-bug-1/lib/Required2.php
> >> function name: normalize_params
> >> number of ops: 14
> >> compiled vars: !0 = $params
> >> line #* E I O op fetch ext
> >return
> >> operands
> >> ------------------------------------------------------------
> >> -------------------------
> >> 11 0 E > EXT_NOP
> >> 1 RECV !0
> >> 13 2 EXT_STMT
> >> 3 INIT_NS_FCALL_BY_NAME
> >> 4 EXT_FCALL_BEGIN
> >> 15 5 FETCH_CLASS_CONSTANT ~1
> >> 'OPTION_STOP_ON_ERROR'
> >> 6 INIT_ARRAY ~2
> >> <true>, ~1
> >> 7 SEND_VAL_EX
> >> ~2
> >> 8 SEND_VAR_EX
> >> !0
> >> 9 DO_FCALL_BY_NAME
> >> 10 EXT_FCALL_END
> >> 11 > RETURN
> >> $3
> >> 18 12* EXT_STMT
> >> 13* > RETURN
> >> null
> >>
> >>
> >> PHP 7.1.4 (OPcache)
> >> ======================
> >>
> >> filename: /tmp/xdebug-bug-1/lib/Required2.php
> >> function name: normalize_params
> >> number of ops: 11
> >> compiled vars: !0 = $params
> >> line #* E I O op fetch ext
> >return
> >> operands
> >> ------------------------------------------------------------
> >> -------------------------
> >> 11 0 E > EXT_NOP
> >> 1 RECV !0
> >> 13 2 EXT_STMT
> >> 3 INIT_NS_FCALL_BY_NAME
> >> 4 EXT_FCALL_BEGIN
> >> 15 5 INIT_ARRAY ~1
> >> <true>, 'stop_on_error'
> >> 6 SEND_VAL_EX
> >> ~1
> >> 7 SEND_VAR_EX
> >> !0
> >> 8 DO_FCALL 0 $1
> >> 9 EXT_FCALL_END
> >> 10 > RETURN
> >> $1
> >>
> >> cheers,
> >> Derick
> >>
> >
> >This is due to
> >https://github.com/php/php-src/commit/183cd048f18fa4b04fb30448a84a54
> cee80a2491,
> >which fixed lineno assignment for list AST nodes. This changed the
> >start
> >lineno of the array from line 17 (the end of the array) to line 15 (the
> >first array element). Of course this is still inaccurate (the actual
> >start
> >line is 13), but it's the closest we can get with the information we
> >currently have available.
> >
> >The problem in this case is that the second SEND_VAR_EX did not bump
> >the
> >lineno. I've fixed this in
> >https://github.com/php/php-src/commit/e433c23b96e81340cd0e2d0b4b7f5f
> ce7f72a931
> >.
> >
> >This required a change to an existing test, which alerted me to some
> >weird
> >behavior I wasn't aware of: https://3v4l.org/6fSRb In backtraces the
> >call
> >is located on the line of it's last argument (in PHP 5.6 the line of
> >the
> >closing ")"). Wouldn't it make more sense to use the starting line of
> >the
> >call? That is, use the same lineno for INIT_FCALL and DO_FCALL?
> >
> >Nikita
>
> It makes sense to me to use the first line, as long as further opcodes
> will have the right line number.
>

I agree the first line makes sense.


> Selfishly, I'd prefer if that change was only made for master, due to the
> increasingly complex tests I need to make for Xdebug's code coverage.


That means it will go into 7.2 and not into any 7.1 fix, correct?
Stanislav Malyshev
Re: [PHP-DEV] Re: Inconsistency in line numbers.
April 15, 2017 11:50PM
Hi!

> behavior I wasn't aware of: https://3v4l.org/6fSRb In backtraces the call
> is located on the line of it's last argument (in PHP 5.6 the line of the
> closing ")"). Wouldn't it make more sense to use the starting line of the
> call? That is, use the same lineno for INIT_FCALL and DO_FCALL?

Since the call happens after evaluating the arguments, if you debug in
IDE and go through the arguments, it'll make IDE prompt jump back
sometimes. Not sure it's a good. Logically, it looks like first argument
eval happens, then call happens, so linking it to ")" makes sense (if
you read it left to right, that's kind of the point where the actual
call happens).

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Stas Malyshev
smalyshev@gmail.com

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Derick Rethans
Re: [PHP-DEV] Re: Inconsistency in line numbers.
April 16, 2017 10:20AM
On Sat, 15 Apr 2017, Stanislav Malyshev wrote:

> Hi!
>
> > behavior I wasn't aware of: https://3v4l.org/6fSRb In backtraces the call
> > is located on the line of it's last argument (in PHP 5.6 the line of the
> > closing ")"). Wouldn't it make more sense to use the starting line of the
> > call? That is, use the same lineno for INIT_FCALL and DO_FCALL?
>
> Since the call happens after evaluating the arguments, if you debug in
> IDE and go through the arguments, it'll make IDE prompt jump back
> sometimes.

Debuggers generally, and Xdebug specifically, only allow interruptions
on function entry or on an EXT_STMT call, so that shouldn't be a problem
here.

OTOH, this is what gdb most definitely does for optimised C code. It
jumps back and forwards through code if the compiler has reorganised
statements.

> Not sure it's a good. Logically, it looks like first argument eval
> happens, then call happens, so linking it to ")" makes sense (if you
> read it left to right, that's kind of the point where the actual call
> happens).

I do agree with that though.

cheers,
Derick

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