[Vm-dev] getting rid of pointer aliasing

[Eliot Miranda]

Hi Nicolas,

On Fri, Mar 4, 2016 at 1:46 PM, Nicolas Cellier <
nicolas.cellier.aka.nice at gmail.com> wrote:

>
> Hi,
> pointer aliasing is evil/dangerous on modern C Compiler.
> Though it's kind of easy to remove most of them.
> For example:
>
>     self cCode:'((long *)addr)[0] = ((long *)(&floatValue))[0]'.
>
> can easily become:
>
>     self cCode: [self mem: addr cp: (self addressOf: floatValue) y: (self
> sizeof: floatValue)].
>
> Modern compiler will generate very efficient code for that.
> Would you like me to proceed?
>

Yes, but please use this form where possible:

    self mem: addr cp: (self addressOf: floatValue) y: (self sizeof:
floatValue)

The cCode: approach is not a;ways needed.  VMClass and SpurMemoryManager
provide implementations of some of the C library that actually work in
simulation.



>
> Nicolas
>
>


-- 
_,,,^..^,,,_
best, Eliot
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