[cfe-dev] Passing Arguments to Back-End

[Eli Friedman]

On Wed, Sep 14, 2011 at 11:55 AM, Justin Holewinski
<justin.holewinski at gmail.com> wrote:
> On Wed, Sep 14, 2011 at 2:54 PM, Justin Holewinski
> <justin.holewinski at gmail.com> wrote:
>>
>> On Wed, Sep 14, 2011 at 2:42 PM, Eli Friedman <eli.friedman at gmail.com>
>> wrote:
>>>
>>> On Wed, Sep 14, 2011 at 11:30 AM, Justin Holewinski
>>> <justin.holewinski at gmail.com> wrote:
>>> > On Wed, Sep 14, 2011 at 12:31 PM, Arnaud Allard de Grandmaison
>>> > <Arnaud.AllardDeGrandMaison at dibcom.com> wrote:
>>> >>
>>> >> Hi Justin
>>> >>
>>> >>
>>> >>
>>> >> You can try the clang’s hidden ‘-llvm’ switch like this :  ‘-llvm
>>> >> –mcpu=mycpu’ to pass options to the backend. I do not know for top of
>>> >> tree,
>>> >> but this works fine with llvm-2.9.
>>> >
>>> > Unfortunately, that does not work, at least not with ToT:
>>> > $ clang -ccc-host-triple ptx32 test1.c -S -O1 -mllvm -mattr=double
>>> > clang (LLVM option parsing): Unknown command line argument
>>> > '-mattr=double'.
>>> >  Try: 'clang (LLVM option parsing) -help'
>>> > clang (LLVM option parsing): Did you mean '-stats=double'?
>>> > For reference, what I want to replace is:
>>> > $ clang -ccc-host-triple ptx32 test1.c -S -O1 -emit-llvm && llc
>>> > -mattr=double test1.s -o test1.ptx
>>>
>>> Try "-Xclang -target-feature -Xclang +double".
>>
>> This seems to be on the right track, but now I'm getting another error:
>> $ clang -ccc-host-triple ptx32 test1.c -S -O1 -Xclang -target-feature
>> -Xclang sm20
>> error: invalid target feature 'double'
>
> Sorry, bad copy-paste job.  Replace sm20 with double.  sm20 should also be a
> valid option for the back-end.

Oh, right, you also need to implement PTXTargetInfo::setFeatureEnabled
(in lib/Basic/Targets.cpp).

-Eli