A serious security bug... caused by no bounds checking.

[Brad Anderson]

On Tuesday, 8 April 2014 at 19:47:02 UTC, Andrei Alexandrescu 
wrote:
> On 4/8/14, 1:47 AM, Paulo Pinto wrote:
>> Me too am glad see bounds checking in D by default.
>
> For the record, dmd used to remove bounds checking in -release 
> mode. I've asked Walter to add a new flag for that, independent 
> from -release, thus keeping release builds safer. It was the 
> first and last time when I used "if you don't do this, I can't 
> work on D anymore" card. True story.
>
>
> Andrei

There is a lot of confusion about this so I looked into it.

dmd still removes bound checking in non- at safe code when you 
specify -release. -noboundscheck just causes it to remove bounds 
checking in @safe code too. This is why I think it should be 
renamed -nosafeboundschecking or something similar.

In dmd's source, useArrayBounds is set to 2 by default (which 
does bounds checking in all code). -release sets it to 1 (which 
only checks @safe code).  -noboundscheck sets it to 0 (which 
causes it to emit no bounds checking).