From: Joost van der Sluis <joost@cnoc.nl>
To: archer@sourceware.org
Subject: Calculating array length
Date: Sun, 07 Jun 2009 10:23:00 -0000 [thread overview]
Message-ID: <1244370173.22994.14.camel@wsjoost> (raw)
Hi all,
First a quick introduction. I'm using gdb to debug my pascal (fpc)
programs, on Linux,OSX and Windows. But there are quite some
difficulties with the gdb<->fpc combination which makes debugging hard.
There were a lot of discussions if some fpc-users should build their own
debugger, but imho it would be better to try to improve the combination
of fpc and gdb. (Although my knowledge of c is pretty bad)
In the past Pierre Muller worked on this but he is not that active
anymore, although he's still willing to help. And I thought that I could
take a look if I could help somewhere.
The archer project is very usefull in this, because with Dwarf-3 some
new things are introduced which can be used to generate better
debug-information for pascal-languages.
I can conclude now already that it's a good thing to look at gdb and fpc
together, because there are comments in the fpc-code like 'we have to
store all identifiers in uppercase into the debug-info, because gdb
needs that', while you can find a comment in the gdb-code like 'all
identifiers are written in capitals by fpc, we have to take care of
that'.
But I also have a lot of questions, I hope this is the right place for
them.
First question is the calculation of the length of an array-type in
type_length_get(), gdbtypes.c. (I'm using the archer-jankratochvil-sla
branch to improve the handling of arrays)
The length is calculated as follows: (count-1)*byte_stride+element_size.
Ok, so why 'count-1'? Count is the actual item-count, why substract it
with one? And why is the element_size added? byte_stride (when defined)
should replace the element_size?
It doesn't make sense to me, as it should be: 'count*byte_stride'?
Can anyone explain this to me?
Regards,
Joost van der Sluis.
next reply other threads:[~2009-06-07 10:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-07 10:23 Joost van der Sluis [this message]
2009-06-07 14:48 ` Jan Kratochvil
2009-06-07 16:06 ` Joost van der Sluis
2009-06-07 17:49 ` Jan Kratochvil
2009-06-07 17:59 ` Jan Kratochvil
2009-06-12 21:24 ` Joost van der Sluis
2009-06-15 11:57 ` Jan Kratochvil
2009-06-15 12:16 ` Jan Kratochvil
2009-06-14 20:30 ` Joost van der Sluis
2009-06-20 22:34 ` Jan Kratochvil
2009-06-22 12:07 ` Joost van der Sluis
2009-06-22 12:15 ` Jan Kratochvil
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