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Groups > comp.lang.c > #140107

Re: Compiler tests

From David Brown <david.brown@hesbynett.no>
Newsgroups comp.lang.c
Subject Re: Compiler tests
Date 2019-01-23 09:22 +0100
Organization A noiseless patient Spider
Message-ID <q2987s$9p1$1@dont-email.me> (permalink)
References (12 earlier) <QHD1E.216796$1D1.179078@fx29.am4> <q27894$a00$1@dont-email.me> <2rI1E.118890$dp2.55232@fx18.am4> <q283te$1fj$1@dont-email.me> <gtN1E.114711$Ur2.9009@fx14.am4>

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On 23/01/2019 00:14, Bart wrote:
> On 22/01/2019 22:02, David Brown wrote:
>> On 22/01/2019 18:30, Bart wrote:
> 
>>> Sometimes the data needs to be embedded in the source code.
> 
>> I regularly embed files as data in C code.  Given your aversion to
>> build systems, you'll be horrified to know that for a number of my
>> projects, "make" uses Python scripts to turn things like images or
>> html files into C files with const arrays of data.  These are defined
>> and initialised as arrays like
>>
>>      const uint8_t index_html = {
>>          "\x48\x54\x54\x50\x2f\x31 ...
>>
>> It is written as an initialised array, declared const.  Anything else
>> - such as using assignments in a function - would be insane in a small
>> embedded system.
> 
> (In my interpreted language I sometimes write stuff like this:
> 
>   zipfile := strinclude "/m/zip.exe"
> 
> 'strinclude' embeds the contents of any file, binary or text, as a
> string constant, and here assigns that to a variable (The purpose of the
> above was to install zip.exe on any system where it wasn't present.)
> 
> In the compiled language, this only works for text files (as strings
> can't have embedded zeros), but it ought to work with html:

Strings, including string literals, can have embedded zeros.  But for
binary files, the addition of the terminating 0 at the end of the string
may be an issue.

> 
>   ichar index_html = strinclude "index.html"
> 

Sure, it would be convenient to have this in the language.  C does not
have this ability.  (The gnu assembler does, so it would be possible to
make a macro that handles this via inline assembly in gcc - but I am
happy with my Python method as it is more flexible.)

> (Here it's important not to use 'const index_html = ...' otherwise the
> string constant is duplicated for each use. When translating to C, some
> compilers already balk at long string constants.))

That makes no sense whatsoever.  Or are you talking about a limitation
in your own language for how you handle strings?  "const" does not make
things duplicated in C.

Compilers may have trouble with long string constants.  To be honest, I
can't remember why I used string constants in the code quoted - usually
my scripts generate code more like :

	const uint8_t hiTable[256] = {
		0x00, 0xc1, 0x81, 0x40, 0x01, 0xc0, 0x80, 0x41,
		...

In the example I used first, the Python code was more complicated than
usual because it combined many files in different ways and pre-generated
some structures that got embedded in the C code as constant arrays.

> 
> 
>>> However, If I try it with gcc, it runs out of memory.
>>
>> What gcc version?  I had no hints of memory issues with my testing
>> with gcc 7 and gcc 8.  It just took time.
> 
> It's 5.1.0. It must have switched from 8.1 at some point (I don't like
> the way the latter messes with my console colours).
> 
> 8.1 is much better and completes this test in 50 seconds (assigning to a
> table of a half a million strings one at a time, so I'm not sure it's
> the same as yours).

OK.  Well, we should both be pleased to see progress here.

> 
> Now I'll have to repeat some tests to give fairer results in my link.
> But at least it means someone does notice these problems and fixes them.

I told you that before - I know of at least one bug report about
handling of long functions.  But that is for realistic long functions
(the reporter was generating code for circuit simulations, I think),
rather than purely artificial ones.

> 
>> gcc does not translate statements one by one as they come in.  It
>> builds up trees in a variety of formats (it has at least two internal
>> formats used at different stages in compilation).  It does many passes
>> over these, even with -O0, for analysis, checking, sorting and
>> re-arranging them.  Register assignment involves working back and
>> forth through these trees.  With code like this, especially on a
>> relatively register-poor architecture like x86 (x86-64 is better than
>> 32-bit mode, but poor compared to many other architectures), this
>> amounts to a great deal of effort for very little purpose.  For more
>> normal functions, it can make a huge difference to the efficiency of
>> the code.
> 
> I have an idea for a new -O-1 optimisation setting for gcc, one below
> -O0. With -O-1, it just runs an embedded version of Tiny C. Now you have
> the advantage of much fast compilation to compensate for slower code.
> 

Feel free to propose it on the gcc mailing lists.  You'll probably get
more polite responses than you risk here.

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Thread

Compiler tests Bart <bc@freeuk.com> - 2019-01-20 00:03 +0000
  Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-20 16:52 +1300
    Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-20 10:27 +0100
      Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 12:37 +0100
        Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 13:08 +0000
          Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 15:02 +0000
            Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 17:31 +0100
              Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 17:08 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 21:40 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 22:41 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 00:39 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 00:36 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-21 16:33 +1300
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 11:58 +0000
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-21 04:15 -0800
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-22 07:53 +1300
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 01:15 -0600
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 12:00 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-24 08:13 +1300
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 13:30 -0600
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 08:22 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 12:23 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 14:42 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 14:17 +0000
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-21 12:46 -0800
                You guys really, really need to get a room (Was: Compiler tests) gazelle@shell.xmission.com (Kenny McCormack) - 2019-01-24 14:05 +0000
          Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-20 17:27 +0100
            Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 17:19 +0000
              Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 09:44 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 12:49 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 15:31 +0100
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-21 14:38 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-21 15:15 +0100
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-21 16:05 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 16:39 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-21 12:51 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 00:16 +0000
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-22 08:43 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 12:31 +0000
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-22 17:49 +0100
                Re: Compiler tests jacobnavia <jacob@jacob.remcomp.fr> - 2019-01-23 11:04 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 11:18 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-21 15:35 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-21 15:49 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-21 17:42 +0100
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 03:18 -0600
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 11:11 +0100
                Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-23 12:18 -0600
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 13:56 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-22 10:55 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 12:07 +0000
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 04:29 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 12:52 +0000
                Re: Compiler tests mark.bluemel@gmail.com - 2019-01-22 05:04 -0800
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 05:18 -0800
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 05:45 -0800
                Re: Compiler tests fir <profesor.fir@gmail.com> - 2019-01-22 05:35 -0800
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-22 15:10 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 17:30 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-22 23:02 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-22 23:14 +0000
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-22 15:45 -0800
                Re: Compiler tests Robert Wessel <robertwessel2@yahoo.com> - 2019-01-22 17:57 -0600
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-22 16:36 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 01:37 +0000
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-22 18:53 -0800
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 09:42 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 09:22 +0100
                Re: Compiler tests James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-23 08:52 -0500
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 15:13 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 14:33 +0000
                Re: Compiler tests James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-23 07:30 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 16:05 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 17:17 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 16:29 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 22:04 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 21:50 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 10:45 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 11:55 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 13:58 +0100
                Re: Compiler tests mark.bluemel@gmail.com - 2019-01-24 05:07 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 14:10 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 14:18 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 15:51 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 15:44 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 17:32 +0000
                Re: Compiler tests scott@slp53.sl.home (Scott Lurndal) - 2019-01-24 19:07 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 20:14 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 22:24 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-24 22:46 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-25 12:34 +1300
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 01:01 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-25 14:15 +1300
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 10:05 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 14:51 +0000
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 09:48 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 10:56 +0100
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 12:08 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 13:28 +0100
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 13:33 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 15:38 +0100
                Re: Compiler tests Mateusz Viste <mateusz@wont.tell> - 2019-01-25 15:08 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 13:53 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 12:25 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 10:03 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 10:08 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 11:14 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 12:02 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 13:37 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 13:58 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 14:26 +0100
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 15:01 +0100
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 15:42 +0100
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-25 10:25 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 14:37 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 16:33 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-25 07:44 -0800
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 17:53 +0100
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-25 10:33 -0800
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 20:43 +0100
                Re: Compiler tests Keith Thompson <kst-u@mib.org> - 2019-01-25 12:17 -0800
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 18:31 +0000
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 20:41 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 21:19 +0000
                Re: Compiler tests Ian Collins <ian-news@hotmail.com> - 2019-01-26 10:24 +1300
                Re: Compiler tests "Pascal J. Bourguignon" <pjb@informatimago.com> - 2019-01-25 22:27 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 22:39 +0000
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 18:46 +0000
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 12:43 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 14:37 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 14:19 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 15:47 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-25 07:17 -0800
                Re: Compiler tests Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-02-03 07:28 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-02-03 12:35 +0100
                Re: Compiler tests Jorgen Grahn <grahn+nntp@snipabacken.se> - 2019-02-03 21:47 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-02-03 22:57 +0100
                Re: Compiler tests Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2019-01-24 06:47 -0800
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-23 20:22 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 22:12 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-23 21:54 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-24 11:41 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-24 23:17 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 11:11 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 12:04 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 14:05 +0100
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 18:40 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-25 22:36 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-25 22:15 +0000
                Re: Compiler tests scott@slp53.sl.home (Scott Lurndal) - 2019-01-25 14:48 +0000
                Re: Compiler tests scott@slp53.sl.home (Scott Lurndal) - 2019-01-25 14:46 +0000
                Re: Compiler tests Ben Bacarisse <ben.usenet@bsb.me.uk> - 2019-01-25 17:48 +0000
                Re: Compiler tests James Kuyper <jameskuyper@alumni.caltech.edu> - 2019-01-23 08:23 -0800
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 16:41 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 16:18 +0000
                Re: Compiler tests David Brown <david.brown@hesbynett.no> - 2019-01-23 17:28 +0100
                Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-23 20:23 +0000
                Re: Compiler tests Robert Wessel <robertwessel2@yahoo.com> - 2019-01-22 17:52 -0600
          Re: Compiler tests Bart <bc@freeuk.com> - 2019-01-20 20:17 +0000
    Re: Compiler tests BGB <cr88192@hotmail.com> - 2019-01-21 00:13 -0600

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