On Sun, Jun 19, 2016 at 11:43 PM, David Wohlferd <d...@limegreensocks.com>
wrote:
> Perhaps this post should be directed toward port maintainers?
>
> Since several global maintainers have now suggested it, I have created a
> patch that deprecates basic asm when used in a function (attached). It
> excludes (ie does not deprecate) top level asm, asm in "naked" functions,
> asm with empty instruction strings, and extended asm.
>
> Building gcc using this patch turns up a few places that use this feature,
> so I fixed them. Where possible, I used builtins to replace the asm. For
> ease-of-review, these changes are in their own patch (attached) and
> obviously this patch should be checked in first.
>
> But before I send these 2 off to gcc-patches, there's a problem. What about
> platforms other than x86/x64? I don't speak other assembler languages, and
> have no setup with which to test them.
>
> I could try to provide patches for other platforms, but it would probably be
> faster for platform experts to just make the changes themselves, rather than
> trying to review my efforts. Especially if they also want to move to
> builtins (which I hope they do).
>
> I could just send the patches and let the chips fall where they may, but if
> there's a less disruptive approach, let me know.
+ /* Acceptable. */
+ asm (" "); /* { dg-warning "Deprecated: asm in function without
extended syntax" } */
You say it is acceptable but then have a dg-warning on it.
Also I think the other place where we should accept basic asm is for
"nop" instructions. I have seen people use that heavily.
Note really I don't like the idea of deprecating basic asm at all.
Thanks,
Andrew
>
> dw
>
> PS I have done a scan for uses of basic asm to get some idea of the scope of
> the remaining work. My results:
>
> All basic asm in trunk: 1,105 instances.
> - Exclude 273 instances with empty strings leaving 832.
> - Exclude 271 instances for boehm-gc project leaving 561.
> - Exclude 202 instances for testsuite project leaving 359.
> - Exclude 282 instances that are (apparently) top-level leaving
>
> ~77 instances of basic-asm-in-a-function to be fixed for gcc builds. Most
> of these are in gcc/config or libgcc/config with just a handful per
> platform. Lists available upon request.
>
> FWIW...
