[llvm-commits] [RFC] Patch 1/3 for the native code compiler of Erlang

[Duncan Sands]

Hi Yiannis,

> On 06/25/2012 11:14 PM, Duncan Sands wrote:
>> Hi,
> Hi Duncan,
>>>> 2. I'm bit concerned  about code like "+ bool isHipeCall = (F ?
>  >>> F->getCallingConv() == CallingConv::HiPE : false);"
>  >> What are exactly your concerns about it?
>  >
>  > it surely has to be wrong? I didn't look at the code in question, but it
>  > sounds like at the point of a call you are looking at details of the callee.
>  > But it should always be possible to codegen a call correctly just from the
>  > declared type of the callee, the calling convention, the actual arguments and
>  > any attributes they may have, without looking at the called function. That
>  > said, I may have completely misunderstood what this is about - but it looks
>  > like a big red flag.
> Maybe I'm the one that misunderstood what you and Anton 're suggesting/concerned
> about or misconceived the LLVM code, but i think that that is exactly what i do:
> i use this "isHipeCall" condition to verify that it is a Hipe CC callee

stop right there!  The calling convention of the callee doesn't matter when you
are generating code for a call, only the calling convention of the call
instruction matters.

You are generating code for the call here, right?  And F is the callee?  If not,
feel free to say: stop right there!

Ciao, Duncan.

  in two
> different circumstances (one to return the correct alignment size in
> "GetAlignedArgumentStackSize" of X86ISelLowering.cpp and one in
> X86RegisterInfo.cpp in order to select the correct TC register class for the X86
> architecture according to HiPE ABI). Grep-ing into my -rather trivial- patch
> should easily verify my sayings! :-) My approach, i.e. just to check the called
> function's cc for these things, is rather similar to GHC's CC (see, for example
> "X86RegisterInfo::getCalleeSavedRegs").
>
> Let me add that Jakob suggested in a previous email that i should check for a
> null-pointer dereference before using "F" in "F->getCallingConv()".
>
>
> Best,
> Yiannis
>
> --
> Yiannis Tsiouris
> Ph.D. student,
> Software Engineering Laboratory,
> National Technical University of Athens
> WWW: http://www.softlab.ntua.gr/~gtsiour
>
>
>
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