ZEND_USER_OPCODE_CONTINUE

16 years ago by johannes@php.net — view source

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Hi,

while implementing a small toy extension (see [1]) I found out that
ZEND_USER_OPCODE_CONTINUE seems to misbehave as it doesn't go to the
next opcode so I ended up in an endless loop executing the same opcode
again and again.

I'm not sure whether we should change the behavior, using a trivial
patch like the attached one or whether we should add a
ZEND_USER_OPCODE_NEXT_OPCODE constant. The first approach looks nicer to
me but might break extensions working around that problem in a hard to
track way (skipping an opcode)

Ideas, comments?

johannes

[1] http://news.php.net/php.pecl.dev/6117

16 years ago by Stefan Esser — view source

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Hi Johannes,

while implementing a small toy extension (see [1]) I found out that
ZEND_USER_OPCODE_CONTINUE seems to misbehave as it doesn't go to the
next opcode so I ended up in an endless loop executing the same opcode
again and again.

I guess that is exactly the required behaviour. How else do you want to
implement an user opcode that transfers control to another opline, like
a special kind of jump opcode.

Stefan
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16 years ago by johannes@php.net — view source

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Stefan,

while implementing a small toy extension (see [1]) I found out that
ZEND_USER_OPCODE_CONTINUE seems to misbehave as it doesn't go to the
next opcode so I ended up in an endless loop executing the same opcode
again and again.

I guess that is exactly the required behaviour. How else do you want to
implement an user opcode that transfers control to another opline, like
a special kind of jump opcode.

ZEND_USER_OPCODE_DISPATCH_TO sounds like the way to do that. But we have
no clean API to set the next opcode and CONTINUE is documented as

#define ZEND_USER_OPCODE_CONTINUE 0 /* execute next opcode */

talking about the "next" one - so /some/ cleanup is needed.

johannes

16 years ago by Christian Seiler — view source

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Hi Johannes,

while implementing a small toy extension (see [1]) I found out that
ZEND_USER_OPCODE_CONTINUE seems to misbehave as it doesn't go to the
next opcode so I ended up in an endless loop executing the same opcode
again and again.

Isn't that expected behaviour? If a normal opcode handler does not
increase the opline, simply returning will also cause re-execution of
the same handler again and again. Why should it be different for user
opcode handlers?

Regards,
Christian