Re: Testing clang, anyone?

[Lloyd Parkes <lloyd%must-have-coffee.gen.nz@localhost>]

On 23/02/2013, at 4:17 AM, christos%astron.com@localhost (Christos Zoulas) 
wrote:

> In article <20130222.101610.244208415.he%uninett.no@localhost>,
> Havard Eidnes  <he%NetBSD.org@localhost> wrote:
>> /*
>> * Note that MAXTSIZ can't be larger than 32M, otherwise the compiler
>> * would have to be changed to not generate "bl" instructions.
>> */
>> #define MAXTSIZ         (16*1024*1024)          /* max text size */
>> 
>> So...  Which is it -- 32M or 16M?  If it can be adjusted to 32M, this
>> would allow one to actually test the clang compiler.  I on my hand
>> don't want to interrupt the bulk build to test, so would appreciate it
>> if someone else could please test the clang build.
> 
> Typically we allow the text segment to be large on other architectures
> that have branch limitations (-fpic -> -fPIC for example), and if the
> branch limits are exceeded during link, the linker issues a warning
> and does not produce an executable. I don't see a point in enforcing
> the limit in the kernel.

Didn't the NetBSD kernel used to generate code into the user space stack? 
Trampolines for signal handling or something? That would require the kernel to 
care about this sort of thing. I never paid attention to trampolines and all I 
really remember is seeing a message about how they had gone away so that NetBSD 
stacks could now be made non-executable on architectures that support such 
permissions.

So, this might just be a left over from past code.

Cheers,
Lloyd