Bug 17 – possible compiler bug causing loss of tags registry information

Bug 17 - possible compiler bug causing loss of tags registry information


Summary:	possible compiler bug causing loss of tags registry information

Status:	RESOLVED FIXED

Product:	ns-3
Classification:	Unclassified
Component:	core
Version:	pre-release
Hardware:	PC Linux

Importance:	P1 blocker
Assigned To:	Mathieu Lacage

URL:
Keywords:

Depends on:
Blocks:
	Show dependency tree / graph

Reported:	2007-04-16 13:00 UTC by Gustavo J. A. M. Carneiro
Modified:	2007-04-19 04:59 UTC (History)
CC List:	0 users

See Also:

Attachments
the patch (2.39 KB, patch) 2007-04-16 13:01 UTC, Gustavo J. A. M. Carneiro	Details \| Diff
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Description Gustavo J. A. M. Carneiro 2007-04-16 13:00:37 UTC

Basically, after some hours of debugging i discovered that TagRegistry::m_registry was being initialized twice in the same program, causing loss of information added to it before the second initialization.  I suspect a compiler bug, but in any case it was very easy to work around it by lazy-initializing the vector.  I committed a patch to my tree; feel free to include it upstream if you want.

Comment 1 Gustavo J. A. M. Carneiro 2007-04-16 13:01:10 UTC

Created attachment 10 [details]
the patch

Comment 2 Mathieu Lacage 2007-04-18 02:19:21 UTC

I would like to see a test-case which shows the bug first. i.e., if you are willing to send me the code, I can look into this.

Comment 3 Mathieu Lacage 2007-04-19 04:59:06 UTC

I have pushed a similar although more complete patch to lazyly initialize m_sorted too. The real issue here I think is that this code could be subject to static variable initialization order problems which might have looked like a double initialization problem to you. 

So, it would be nice to get some testing feedback on the version I pushed. Marking bug as fixed.