Johannes Pfau via D.gnu
d.gnu at puremagic.com
Tue May 5 10:51:51 PDT 2015
Am Tue, 05 May 2015 11:37:17 +0000
schrieb "Mike" <none at none.com>:
> So, perhaps in my ignorance, I have to say that I don't need a
> -ffreestanding option, but I don't consider myself much of an
> expert in this field. If you know of a need for the
> -ffreestanding option, please let it be known.
> What I really need is more granular control of the language
> features, either by adding compiler switches, or delegating
> implementation to the runtime. My dream would be to have runtime
> .di files inform the compiler what the language features look
> like, and have the compiler use that information to generate
> optimized code or compiler errors if the runtime doesn't provide
> what everything compiler needs.
Isn't this simply two ways of looking at the same thing? You want to
disable language features (I guess mostly those requiring runtime
hooks), -ffreestanding disables all these features.
I realize you want fine-grained control. But then:
-fno-utf-support (foreach over utf strings)
From an implementation point of view these are the same and
fine-grained switches are easy to support.
Access using .di is then simple to add as well. If the compiler is
clever it can look if the required features/hooks are implemented. This
requires some compiler work. Simpler alternative: Enum values in
special d module (e.g. rt.config) enum RUNTIME_SUPPORTS_GC = false;
> At the moment, the most pressing issue for me is the phony
> support I have to add for TypeInfo and the removal of dead code
> (or lack there of) due to GCC bug 192. Some binaries I've
> created are so full of TypeInfo stuff that I can't even get them
> to fit in my MCU's flash memory for testing and debugging. Not
> to mention the added upload time it takes, diminishing the
> efficiency of my development cycle.
I'll implement fno-rtti next weekend. We can think about more
fine-grained solutions in the future but fno-rtti should be a good
> I remember from previous discussions that there was work to be
> done in binutils to get better LTO and dead-code removal. I'd be
> interested in hearing more details about that too.
> Thanks for the continued support,
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