[cfe-dev] Parallelism TS implementation and feasibility of GPUexecution policies

C Bergström cbergstrom at pathscale.com
Mon Apr 6 15:22:47 PDT 2015


On Tue, Apr 7, 2015 at 4:47 AM, Eli Bendersky <eliben at google.com> wrote:
>
>
> On Mon, Apr 6, 2015 at 11:48 AM, Régis Portalez
> <regis.portalez at altimesh.com> wrote:
>>
>> Hi.
>>
>> Sorry to interrupt, but I understood there is way to emit llvm ir from
>> cuda code?
>>
>
> In general, the Clang frontend (-cc1) can generate LLVM IR for the nvptx
> triples/targets, when passed -fcuda-is-device. To use this in practice,
> you'll need to supply a bunch of things in headers (definitions of builtins,
> CUDA types and such), and no such headers exist in the open yet. Clang won't
> be able to parse the NVIDIA headers as these collide with the standard C++
> headers in some ways.

The old cuda headers used to be permissively licensed. (below)

Those headers are probably sufficient to get things "rolling", but I
don't know if they are really a good start. (Not to mention you'd be
missing a runtime)

The problem is that you'd have to do 2 passes with different
(conflicting) defines. Once for host and once for device. To get
host+device to play nice together is a b*. We have this resolved in
our clang, but it's really specific to our compilation flow. A general
solution would most likely involve extensive changes to the headers or
a rewrite. :/

I've fought with this for the past 5 years. I'll try to help in a
general way if/where I can.

Old CUDA header license
----------
/*
 * Copyright 1993-2010 NVIDIA Corporation.  All rights reserved.
 *
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 *
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 * international Copyright laws.  Users and possessors of this source code
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 * in individual and commercial software.
 *
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