GCC documentation: porting to Sphinx

[Martin Liška]

On 6/4/21 5:10 PM, Martin Sebor wrote:
> On 6/3/21 4:56 AM, Martin Liška wrote:
>> On 6/2/21 10:41 PM, Martin Sebor wrote:
>>> On 5/31/21 7:25 AM, Martin Liška wrote:
>>>> Hello.
>>>>
>>>> I've made quite some progress with the porting of the documentation and
>>>> I would like to present it to the community now:
>>>> https://splichal.eu/scripts/sphinx/
>>>
>>
>> Hello.
>>
>> Thank you for the review.
>>
>>> Just a few issues I noticed in the warnings section:
>>>
>>> The headings of some warnings mention the same option twice (e.g.,
>>> -Wabi, -Wabi, -Wno-abi;  -Wdouble-promotion, -Wdouble-promotion,
>>> -Wno-double-promotion;  -Winit-self, -Winit-self, -Wno-init-self).
>>> This looks like a pretty pervasive problem.
>>
>> You are right, I fixed that.
> 
> Looks good.
> 
>>
>>>
>>> Mentioning the -Wno-xxx option is redundant in a heading for -Wxxx.
>>
>> Yes. Good reason for that is that Sphinx can then generated properly links
>> to the current non-documented version of the option. Hope it's improvement
>> over the current situation?

Hello.

Back to this after some thinking.

> 
> I think the linking is helpful.  But for warnings, the documented
> convention is to only mention the one that's not the default:
> 
>    This manual lists only one of the two forms, whichever is not
>    the default.
> 
> so including both blurs this (IMO rather subtle) distinction.
> In addition, in options whose description says something like
> "This warning is enabled by -Wall." it's now less clear which
> one is the one the "this" refers to (see for example
> -Wchar-subscripts).

Yes, that's really confusing and we should likely explicitly document
both options as shown here (-Wno-shift-overflow3):

https://splichal.eu/scripts/sphinx/demo/_build/html/#cmdoption-Wno-shift-overflow3

Doing that, one has 2 unique links, that would be needed for get_option_url function.
Plus, both :option:`-Wfoo` and :option:`-Wno-foo` references are going to work.

> 
> If the heading can't be changed at a minimum we'll need to update
> the convention above, e.g., by saying that the first option mentions
> is the default. But again, I think this is too subtle for the casual
> reader to pick up on.  The fact that the sentence quoted above appears
> under -Wfatal-errors doesn't help.  We should also work on updating
> the "This option is in -Wall." either to name the specific option
> it refers to, or consider moving that into a Note box like the one
> listing the languages the option applies to.)

Yes, we should explicitly mark one of them as default value,
something like "Default option value for -Wshift-overflow3."?
And the corresponding counter-part should have "Enabled by -Wall.". I'm not fully
convinced about usage of note as it's quite big visual component.

> 
>>
>>>
>>> The headings of some other warnings also mention options that are
>>> only remotely related to them.  E.g., -Wformat has all these:
>>>
>>>    -Wformat, -Wno-format, -ffreestanding, -fno-builtin, -Wformat=
>>>
>>> (I see the same problem in the attributes section where the headings
>>> for some attributes include option names).
>>>
>>> That seems quite puzzling.  I assume it's a consequence of having
>>> index entries for the related options, but I don't think making
>>> them visible in the headings is helfpful.
>>
>> Oh, you are right. It was consequence of wrong parsing of index entries.
>> It should be fixed now.
> 
> Looks good.
> 
>>
>>>
>>> Headings that in the manual today include a level like
>>>
>>>    -Wformat-overflow
>>>    -Wformat-overflow=level
>>>
>>> don't mention the level in the Spinx manual:
>>>
>>>    -Wformat-overflow, -Wno-format-overflow
>>>
>>> When the /level/ is then discussed in the rest of the text it's
>>> not clear what it refers to.
>>
>> Should be also fixed now.
> 
> Also looks good.
> 
>>
>> Can you please take a look at the current output and give me a feedback?
> 
> I noticed another minor issue that may already have been pointed
> out by someone else.  Under -Wall (and -Wextra), some option names
> are prefixed by :option: (e.g., (only with :option:-O2``).  Looks
> like some sort of a transcription bug?

Yes, that should be fixed now. Most comment root cause is that some inline
roles are wrapped (that's not supported).

> 
> And a couple of questions:
> 
> References to options with an argument like -Warray-bounds=1 are
> rendered in a way that makes it look like there's a space before
> the equals: -Warray-bounds =1, with  the =1 being in a different
> color and not part of the hyperlink. Is there a way to make it look
> like there is no space?

Likely not. That's the best I was able to come up with. Reason why the '=1'
argument is in :samp: is that :option:`-Wfoo=123` does not properly generate link
to the option directive. And there's actually no space in HTML, it's only slightly
visually separated and PDF version is fine for me.

> 
> I like how options are automatically linked, and I'd like to see
> the same for other references like to attributes.  Can that be
> automated as part of the migration or should we/I try to tackle
> it in a followup?

Right now, I abuse a bit .. option:: my_attribute directive for them.
For the future, yes, one can make a link to them with :option:`my_attribute`.

Thanks for useful feedback!
Martin

> 
> In any event, thanks for working so hard on making this turn out
> great!
> 
> Martin
> 
>> Thanks,
>> Martin
>>
>>>
>>> Martin
>>>
>>>>
>>>> Note the documentation is automatically ([1]) generated from texinfo with a GitHub workflow ([2]).
>>>> It's built on the devel/sphinx GCC branch which I periodically with the master branch. One can
>>>> see the current source .rst files here: [3].
>>>>
>>>> Changes made since the last time:
>>>> - a shared content is factored out ([4])
>>>> - conditional build is fully supported (even for shared parts)
>>>> - manual pages look reasonable well
>>>> - folders are created for files which have >= 5 TOC tree entries
>>>> - various formatting issues were resolved
>>>> - baseconf.py reads BASE-VER, DEV-PHASE, .. files
>>>>
>>>> I've got couple of questions:
>>>>
>>>> 1) Do we have to you the following cover text?
>>>>         Copyright (c) 1988-2020 Free Software Foundation, Inc.
>>>>
>>>>         Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "GNU General Public
>>>>         License" and "Funding Free Software", the Front-Cover texts being (a) (see below), and with the Back-Cover Texts being (b) (see below).  A copy of the license is included in the gfdl(7) man page.
>>>>
>>>>         (a) The FSF's Front-Cover Text is:
>>>>
>>>>              A GNU Manual
>>>>
>>>>         (b) The FSF's Back-Cover Text is:
>>>>
>>>>              You have freedom to copy and modify this GNU Manual, like GNU
>>>>              software.  Copies published by the Free Software Foundation raise
>>>>              funds for GNU development.
>>>>
>>>> 2) Do we want to generate fsf-funding, gpl and gfdl manual pages?
>>>> 3) Do we want to preserve the current strange copy mechanism for ./gcc/doc/tm.texi.in ?
>>>> 4) Do we want a copyright header for the created .rst files?
>>>>
>>>> Thoughts?
>>>> Thanks,
>>>> Martin
>>>>
>>>> [1] https://github.com/davidmalcolm/texi2rst
>>>> [2] https://github.com/davidmalcolm/texi2rst/actions
>>>> [3] https://github.com/marxin/texi2rst-generated/tree/master/sphinx
>>>> [4] https://github.com/marxin/texi2rst-generated/tree/master/sphinx/share
>>>
>>
>