[LLVMdev] frontend support for cross-compilation?

[John Regehr]

Got it-- thanks Chris.

John


On Tue, 1 Jul 2008, Chris Lattner wrote:

>
> On Jul 1, 2008, at 9:45 PM, John Regehr wrote:
>
>> Thanks Chris.  I'll follow any ongoing discussion about this.
>> Unless I'm
>> missing something, customizable widths for integer types is
>> necessary to
>> achieve source-level compatibility with existing cross-compilers.
>>
>> It would be great to see the fronend being parameterized by integer
>> widths
>> at runtime.  There would be no noticable loss of efficiency and this
>> would
>> avoid the obnoxious and error-prone situation of keeping many C
>> frontends
>> sitting around.
>>
>> FWIW CIL just lately became parameterizable at runtime with
>> machine-specific information and it's really handy.
>
> Hi John,
>
> Just to be clear, LLVM fully supports cross compilation.  This issue
> is a problem for LLVM generating code for any target where
> sizeof(int) != 32, regardless of whether you are natively compiling or
> cross compiling.  The previous discussion was in the context of the
> PIC port.
>
> If you follow the thread, you'll see that this is really easy to fix
> and only impacts promotion of return values.  LLVM fully supports your
> front-end mapping int/long/etc onto whatever size integer you want,
> this is only specific to the one case of return value promotion.
>
> -Chris
>
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