[Buildroot] [PATCH 1/2] gcc: remove option on SJLJ exceptions

[Michael S. Zick <minimod@morethan.org>]

On Thu July 29 2010, Thomas Petazzoni wrote:
> Hello,
> 
> On Thu, 29 Jul 2010 05:38:06 -0500
> "Michael S. Zick" <minimod@morethan.org> wrote:
> 
> > And of course you confirmed that the Lua package's
> > error handling still works properly, complete with
> > same backtrace that is produced when SJLJ exceptions are enabled.
> 
> No, I did not.
> 
> > You did make that test didn't you?
> 
> Why do you need to be so aggressive ? It is possible that removing this
> option was a mistake, but there's *really* no need to be so
> aggressive. It only reduces the motivation to look at the problem...
>

The last time this subject came up on the ML tests seemed to indicate
that the option was required by the Lua package.

I just presumed you have been following the mailing list postings.
 
> So, trying to be constructive, how can I test that Lua still produces
> correct backtraces ? (I'm not a Lua programmer at all).
> 

Pass an illegal value to a library routine or to a routine that you write.
"Lua" refers to both a set of C libraries and to the interactive mode which
uses those same libraries.

So testing with the interactive mode should be enough to see a backtrace.

Since the libraries (written in ANSI C) are quite close to the interactive
environment (usually only one or two calls away) you will not see a very
long backtrace unless you write a function or two of your own, but you will
get one.

I.E:
mszick at wolf466:~$ lua
Lua 5.1.4  Copyright (C) 1994-2008 Lua.org, PUC-Rio
> os.exit("String Value")
stdin:1: bad argument #1 to 'exit' (number expected, got string)
stack traceback:
        [C]: in function 'exit'
        stdin:1: in main chunk
        [C]: ?

The "[C]" just means that is a hunk of compiled C code, for which the 
language does not have any more information to give you about it.

And: os.exit(0) should get you back out of the interactive Lua (or ctrl-D).

Mike

> Thanks,
> 
> Thomas