* What is LSDA?
@ 2002-05-29 5:41 Michal Ludvig
2002-05-29 11:02 ` Richard Henderson
2002-05-29 11:03 ` Richard Henderson
0 siblings, 2 replies; 5+ messages in thread
From: Michal Ludvig @ 2002-05-29 5:41 UTC (permalink / raw)
To: gcc, gdb, rth
Hi all,
In dwarf-2 debug_frame generated by GCC 3.1 I can sometimes see an
augmentation "L", that indicates a presence of pointer to something
called "LSDA (Language Specific Data Area)" in appropriate CIE/FDEs.
My questions are:
- What is LSDA for?
- When does GCC generate it?
- Should I support it in GDB? Do I need it for something?
Thanks,
Michal Ludvig
--
* SuSE CR, s.r.o * mludvig@suse.cz
* +420 2 9654 5373 * http://www.suse.cz
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: What is LSDA?
2002-05-29 5:41 What is LSDA? Michal Ludvig
@ 2002-05-29 11:02 ` Richard Henderson
2002-05-29 11:03 ` Richard Henderson
1 sibling, 0 replies; 5+ messages in thread
From: Richard Henderson @ 2002-05-29 11:02 UTC (permalink / raw)
To: Michal Ludvig; +Cc: gcc, gdb
On Wed, May 29, 2002 at 02:41:24PM +0200, Michal Ludvig wrote:
> My questions are:
> - What is LSDA for?
> - When does GCC generate it?
It's data in some opaque format to be consumed by the language's
exception personality routine to decide whether and where an
exception should be handled.
> - Should I support it in GDB? Do I need it for something?
No.
r~
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: What is LSDA?
2002-05-29 5:41 What is LSDA? Michal Ludvig
2002-05-29 11:02 ` Richard Henderson
@ 2002-05-29 11:03 ` Richard Henderson
2002-05-30 0:42 ` Michal Ludvig
1 sibling, 1 reply; 5+ messages in thread
From: Richard Henderson @ 2002-05-29 11:03 UTC (permalink / raw)
To: Michal Ludvig; +Cc: gcc, gdb
On Wed, May 29, 2002 at 02:41:24PM +0200, Michal Ludvig wrote:
> In dwarf-2 debug_frame generated by GCC 3.1 I can sometimes see an
> augmentation "L"...
Wait.. You're seeing this in .debug_frame? That's not right.
It should only be present in .eh_frame.
r~
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: What is LSDA?
2002-05-29 11:03 ` Richard Henderson
@ 2002-05-30 0:42 ` Michal Ludvig
2002-05-30 3:12 ` Richard Henderson
0 siblings, 1 reply; 5+ messages in thread
From: Michal Ludvig @ 2002-05-30 0:42 UTC (permalink / raw)
To: Richard Henderson; +Cc: gcc, gdb
Richard Henderson wrote:
> On Wed, May 29, 2002 at 02:41:24PM +0200, Michal Ludvig wrote:
>
>>In dwarf-2 debug_frame generated by GCC 3.1 I can sometimes see an
>>augmentation "L"...
>
> Wait.. You're seeing this in .debug_frame? That's not right.
> It should only be present in .eh_frame.
You're right. It appears in .eh_frame only.
What other differences can I expect between eh_frame and debug_frame?
For now I handle both of them almost in the same way.
Exceptions are: Different CIE-id, different way of finding the right CIE
for a given FDE, and from now on ignoring LSDA in eh_frame.
Is there something else?
Michal Ludvig
--
* SuSE CR, s.r.o * mludvig@suse.cz
* +420 2 9654 5373 * http://www.suse.cz
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: What is LSDA?
2002-05-30 0:42 ` Michal Ludvig
@ 2002-05-30 3:12 ` Richard Henderson
0 siblings, 0 replies; 5+ messages in thread
From: Richard Henderson @ 2002-05-30 3:12 UTC (permalink / raw)
To: Michal Ludvig; +Cc: gcc, gdb
On Thu, May 30, 2002 at 09:42:15AM +0200, Michal Ludvig wrote:
> What other differences can I expect between eh_frame and debug_frame?
> For now I handle both of them almost in the same way.
> Exceptions are: Different CIE-id, different way of finding the right CIE
> for a given FDE, and from now on ignoring LSDA in eh_frame.
> Is there something else?
The encoding of the addresses can be substantially different.
Pc-relative and base-relative are the popular ones. You'd
need target-specific hackery to know what the base address is
for the base-relative addresses.
That more and more differences crept in is the reason why we no
longer attempt to emit only one of .debug_frame or .eh_frame.
r~
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2002-05-30 10:12 UTC | newest]
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2002-05-29 5:41 What is LSDA? Michal Ludvig
2002-05-29 11:02 ` Richard Henderson
2002-05-29 11:03 ` Richard Henderson
2002-05-30 0:42 ` Michal Ludvig
2002-05-30 3:12 ` Richard Henderson
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