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From: Andrew Cagney <cagney@gnu.org>
To: Daniel Jacobowitz <drow@false.org>
Cc: gdb-patches@sources.redhat.com
Subject: Re: [rfc] trad-frame change
Date: Fri, 19 Mar 2004 00:09:00 -0000	[thread overview]
Message-ID: <40464302.3060308@gnu.org> (raw)
In-Reply-To: <20040303202954.GA29400@nevyn.them.org>


>>> So there are really two variants - o32sigreturn and rt_sigreturn (with 
>>> constants computed from the architecture vector)?
> 
> 
> I don't see much point in distinguishing them that way, honestly.  The
> difference between o32 sigreturn and o32 rt_sigreturn is about the same
> as the difference between n32 and n64.  Sure, you could put the
> constants in the architecture tdep vector... but why bother?
> 
> And it may be silly, but there's nothing stopping a theoretical
> hand-written program from using a different ABI's sigreturn syscall.

Like you said, theoretical - program for what is, not what might be, but 
what ever.

>>>> >What would _really_ be nice would be a way to pass the kind from the
>>>> >sniffer (which really just calls PC_IN_SIGTRAMP) to the frame creation
>>>> >code... not have to read inferior memory to figure out which it is,
>>>> >twice.
>>
>>> 
>>> I'll think about that, I may need to change the unwinder object anyway.
>>> 
>>> Just remember that it is the number of unique addresses accessed (0 vs 1 
>>> vs 2 ...) and not the number of times each address is accessed that is 
>>> going to be important - multiple accesses to a single address can be 
>>> handled with a cache.
> 
> 
> We really should turn on that cache someday.

Not that cache, a new one, yes, someday.

Andrew



WARNING: multiple messages have this Message-ID
From: Andrew Cagney <cagney@gnu.org>
To: Daniel Jacobowitz <drow@false.org>
Cc: gdb-patches@sources.redhat.com
Subject: Re: [rfc] trad-frame change
Date: Wed, 03 Mar 2004 20:41:00 -0000	[thread overview]
Message-ID: <40464302.3060308@gnu.org> (raw)
Message-ID: <20040303204100.xT1ZwNHWlUWSWMKqoR7kwqn0N8NgwUWNLTDt3gfYZYU@z> (raw)
In-Reply-To: <20040303202954.GA29400@nevyn.them.org>


>>> So there are really two variants - o32sigreturn and rt_sigreturn (with 
>>> constants computed from the architecture vector)?
> 
> 
> I don't see much point in distinguishing them that way, honestly.  The
> difference between o32 sigreturn and o32 rt_sigreturn is about the same
> as the difference between n32 and n64.  Sure, you could put the
> constants in the architecture tdep vector... but why bother?
> 
> And it may be silly, but there's nothing stopping a theoretical
> hand-written program from using a different ABI's sigreturn syscall.

Like you said, theoretical - program for what is, not what might be, but 
what ever.

>>>> >What would _really_ be nice would be a way to pass the kind from the
>>>> >sniffer (which really just calls PC_IN_SIGTRAMP) to the frame creation
>>>> >code... not have to read inferior memory to figure out which it is,
>>>> >twice.
>>
>>> 
>>> I'll think about that, I may need to change the unwinder object anyway.
>>> 
>>> Just remember that it is the number of unique addresses accessed (0 vs 1 
>>> vs 2 ...) and not the number of times each address is accessed that is 
>>> going to be important - multiple accesses to a single address can be 
>>> handled with a cache.
> 
> 
> We really should turn on that cache someday.

Not that cache, a new one, yes, someday.

Andrew



  parent reply	other threads:[~2004-03-03 20:41 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-03-19  0:09 Andrew Cagney
2004-03-03 16:43 ` Andrew Cagney
2004-03-03 16:49 ` Daniel Jacobowitz
2004-03-19  0:09   ` Daniel Jacobowitz
2004-03-19  0:09   ` Andrew Cagney
2004-03-03 18:34     ` Andrew Cagney
2004-03-19  0:09     ` Daniel Jacobowitz
2004-03-03 18:53       ` Daniel Jacobowitz
2004-03-19  0:09       ` Andrew Cagney
2004-03-03 20:20         ` Andrew Cagney
2004-03-03 20:29         ` Daniel Jacobowitz
2004-03-19  0:09           ` Daniel Jacobowitz
2004-03-19  0:09           ` Andrew Cagney [this message]
2004-03-03 20:41             ` Andrew Cagney
2004-03-05 14:52         ` Andrew Cagney
2004-03-19  0:09           ` Andrew Cagney

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