llvm dev - Sep 2014 - [LLVMdev] RFC: Another go at a cross compiler config file.

A while back (2012) there were a few messages related to using YAML 
config files to set up how clang would build stuff, especially for cross 
compilers. My ELLCC project is entirely cross compilation focused, so 
today I decided to play around with the config file idea. Right now it 
only handles replacing a "-target foo" option with the options defined
in the file foo in the resource/config directory, but I think it has 
potential for doing quite a bit more.

I describe it a little more on my blog at http://ellcc.org/blog/?p=11877

Any comments/criticisms would be greatly appreciated.

-Rich
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> On Sep 5, 2014, at 7:23 PM, Richard Pennington <rich at pennware.com>
wrote:
> 
> A while back (2012) there were a few messages related to using YAML config
files to set up how clang would build stuff, especially for cross compilers. My
ELLCC project is entirely cross compilation focused, so today I decided to play
around with the config file idea. Right now it only handles replacing a
"-target foo" option with the options defined in the file foo in the
resource/config directory, but I think it has potential for doing quite a bit
more.
> 
> I describe it a little more on my blog at http://ellcc.org/blog/?p=11877
<http://ellcc.org/blog/?p=11877>
> 
> Any comments/criticisms would be greatly appreciated.
There aren’t a lot of details on your blog, but the basic idea sounds great. I’m
looking forward to seeing patches for this!
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On Fri, Sep 05, 2014 at 09:23:34PM -0500, Richard Pennington
wrote:
> Right now it only handles replacing a "-target foo" option
> with the options defined in the file foo in the resource/config
> directory, but I think it has potential for doing quite a bit more.
Please don't overload the -target option like that, but make it a
separate option.

Joerg

> On Sep 8, 2014, at 10:14 AM, Joerg Sonnenberger <joerg at
britannica.bec.de> wrote:
> 
> On Fri, Sep 05, 2014 at 09:23:34PM -0500, Richard Pennington wrote:
>> Right now it only handles replacing a "-target foo" option
>> with the options defined in the file foo in the resource/config
>> directory, but I think it has potential for doing quite a bit more.
> 
> Please don't overload the -target option like that, but make it a
> separate option.
I disagree. One of the problems with clang’s driver now is that we have such a
long list of built-in targets. From the user’s point of view, whether the target
settings come from a yaml file or from hardcoded logic in the driver should be
an implementation detail. It would be great if we could default to specify _all_
targets like this, and then choose which targets to build into the driver based
solely on performance. (It will be a while before any mechanism like this can
support all the features for some of the more complicated targets, so I’m not
proposing that we completely switch to that approach now, but I would like to
see us move in that direction.)

On that note, Richard, do you have any thoughts on how we could support building
these yaml specification into the driver? It seems like many of the targets that
are currently hardcoded could be handled with this approach, but the
compile-time cost of reading a separate yaml file would be unacceptable in some
situations.

—Bob

I've updated my blog with the current state of my compilation 
configuration prototype. http://ellcc.org/blog/?p=13246
Again, any comments/criticisms greatly appreciated.

-Rich

On 09/05/2014 09:23 PM, Richard Pennington wrote:
> A while back (2012) there were a few messages related to using YAML 
> config files to set up how clang would build stuff, especially for 
> cross compilers. My ELLCC project is entirely cross compilation 
> focused, so today I decided to play around with the config file idea. 
> Right now it only handles replacing a "-target foo" option with
the
> options defined in the file foo in the resource/config directory, but 
> I think it has potential for doing quite a bit more.
>
> I describe it a little more on my blog at http://ellcc.org/blog/?p=11877
>
> Any comments/criticisms would be greatly appreciated.
>
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Hi,

Did this make it into review / commit?  It's probably too late for 3.6 if it
didn't, but I'd love to see it in 3.7.  It would also be nice if this
support could be something a bit more general in LLVM, rather than specifically
in clang, so that other llvm tools (e.g. llvm-objdump) could take advantage of a
similar format for target description files if they need something more than
just the triple argument.

David
> On 15 Sep 2014, at 13:09, Richard Pennington <rich at pennware.com>
wrote:
> 
> I've updated my blog with the current state of my compilation
configuration prototype. http://ellcc.org/blog/?p=13246
> Again, any comments/criticisms greatly appreciated.
> 
> -Rich
> 
> On 09/05/2014 09:23 PM, Richard Pennington wrote:
>> A while back (2012) there were a few messages related to using YAML
config files to set up how clang would build stuff, especially for cross
compilers. My ELLCC project is entirely cross compilation focused, so today I
decided to play around with the config file idea. Right now it only handles
replacing a "-target foo" option with the options defined in the file
foo in the resource/config directory, but I think it has potential for doing
quite a bit more.
>> 
>> I describe it a little more on my blog at
http://ellcc.org/blog/?p=11877
>> 
>> Any comments/criticisms would be greatly appreciated.
>> 
> 
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