[M3devel] fault reports beyond 100mill lines?

[Jay K]

See below:
 >> The line number is in an integer along with a 5 bit fault code.

Maybe that isn't clear -- they are in the same integer, 32bits or 64bits.
4 billion / 32 is roughly 100 million.
 
 - Jay
 


Date: Wed, 7 Jul 2010 11:56:43 +0800
From: ttmrichter at gmail.com
To: m3devel at elegosoft.com
Subject: Re: [M3devel] fault reports beyond 100mill lines?

Why the magic number of 100,000,000?  Why not 4 billion, say?


On 7 July 2010 04:35, Jay K <jay.krell at cornell.edu> wrote:


I'm pretty settled on silently losing line numbers over 100 million.
If the host and target are 64 bits it preserves far more.
If someone produces such a file, and it compiles and runs, but gets a runtime error in their code on the wrong line, they can claim they found a compiler bug...


 - Jay

----------------------------------------
> From: jay.krell at cornell.edu
> To: m3devel at elegosoft.com
> Date: Tue, 6 Jul 2010 20:21:08 +0000
> Subject: [M3devel] fault reports beyond 100mill lines?



>
>
> It appears that if a file has over around 100 million lines, that fault reports (nil deref, subrange out of bounds, etc.) get the wrong line number.
> Leave it as ("qualit of implementation"?) or fail an assertion in the compiler earlier (leaving anyone with a huge file kind of stuck (generated?) or, unlikely, expand the range?
> The line number is in an integer along with a 5 bit fault code.
>   We could also allow much larger numbers on 64bit targets.
>
>
> This is just because there's a "FIXME" comment in parse.c.
> The code is basically right and I'm adding comments and perhaps assertions.
> Certainly we can assert that the fault code is in range.
>
>
> I think I prefer silently losing bits in the line number, or conveting it to 0 if it is out of bounds or pinning it to maxint.
>   Though it'd be maxint  / 32 which is less "special" looking if someone ever saw it.. though the runtime could
>   report maxint / 32 as maxint.
>
>  - Jay
>
>
                                         

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