Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #136565

Re: software disenchantment

From BGB <cr88192@hotmail.com>
Newsgroups comp.lang.c
Subject Re: software disenchantment
Date 2018-10-10 12:45 -0500
Organization albasani.net
Message-ID <ppldrc$n44$1@news.albasani.net> (permalink)
References (3 earlier) <W58vD.9716$I67.8673@fx15.am4> <8a4514a7-0185-4de5-8033-006a7bbc10f4@googlegroups.com> <0vkvD.14918$Nt6.14398@fx19.am4> <7FkvD.14919$Nt6.2825@fx19.am4> <968306fe-f05b-45cb-93a4-3081ec0d2fd0@googlegroups.com>

Show all headers | View raw

On 10/10/2018 7:49 AM, Malcolm McLean wrote:
> On Wednesday, October 10, 2018 at 11:39:11 AM UTC+1, Bart wrote:
>> On 10/10/2018 11:28, Bart wrote:
>>
>>> Then you /are/ looking at a cut-down C, but you wouldn't cut down
>>> essentials such as for and while loops. You would get rid of most of the
>>> processor
>>
>> I mean most of the preprocessor.
>>
>> Getting rid of the processor would be rather drastic.
>>
> We need to get rid of the "sticky" rule with C. The rule that means you have
> to pull in a system header which includes dozens of other headers, just
> because you need the symbol "DWORD" for some reason.
> How to do that isn't obvious.
> 

One "possible" option is partly replacing header inclusion with 
database-like metadata, but pulling this off effectively without 
breaking things in the language is harder.


For example, compiling Doom in my case (with my compiler for my ISA), it 
is (currently) averaging about 9ms per translation unit for header 
inclusion (for an overall compile time of around 2.9 seconds); skipping 
preprocessing could theoretically save ~ 0.6 seconds overall, and 
roughly 45% of the time spent in the frontend (possibly itself a little 
faster due to not needing to deal with all of the stuff pulled in from 
headers).


Though, in this process, 1.1s is currently spent mostly in codegen, and 
~ 0.7s is spent in file-loading (mostly IO). Note that each header is 
loaded once and then added to a cache (with ASCII/UTF-8/16 normalization 
done when the file is initially read-in).

I once considered a VFS for system headers, but haven't done so yet as 
the savings may not be worth the hassle involved.

Fewer obvious ways to speed up the codegen; a lot of the time is 
apparently spent mostly in the register allocator and logic for dealing 
with labels and similar (followed by misc stuff like emitting words to 
sections and performing relocs).

There is no ASM stage, and doing ASM output currently takes ~ 3.5s, in 
which case a bunch of time is spent mostly in the C++ code inside of 
MSVCRT's sprintf implementation (if it mattered, could experiment with 
doing a more specialized 'sprintf').


Optional operations, like dumping AST's or 3AC IR output may also add 
considerably to the overall running time.

Building the compiler with optimizations enabled reduces overall build 
time to ~ 1.7s (still spends ~ 0.7s in IO), with ~ 3ms per TU for 
preprocessing, ...

All this seems fairly acceptable.

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

software disenchantment Bart <bc@freeuk.com> - 2018-10-06 15:13 +0100
  Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-06 09:54 -0700
  Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-06 10:26 -0700
    Re: software disenchantment fir <profesor.fir@gmail.com> - 2018-10-14 04:26 -0700
  Re: software disenchantment antispam@math.uni.wroc.pl - 2018-10-09 18:20 +0000
    Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-09 11:54 -0700
      Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-09 21:22 +0100
        Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-09 17:47 -0700
          Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 11:28 +0100
            Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 11:38 +0100
              Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-10 05:49 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-10 15:47 +0200
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 09:58 -0400
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-10 14:39 +0000
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-10 09:42 -0700
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 13:18 -0400
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 20:31 +0100
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 17:53 -0500
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 10:06 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 02:34 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 12:03 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 03:59 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 16:56 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 09:02 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 19:39 +0200
                Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-15 19:53 +0000
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-16 03:54 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 20:25 +0200
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 13:16 +0000
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 07:15 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 17:05 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 09:15 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 17:33 +0000
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 19:53 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 17:59 +0100
                Re: software disenchantment nobody@example.org (Scott) - 2018-10-10 16:53 +0000
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 12:45 -0500
                Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-10 11:04 -0700
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 14:22 -0500
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 15:53 -0400
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 09:06 +1300
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-10 13:21 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-10 20:27 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 22:54 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:01 +1300
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:05 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 23:16 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:22 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-10 23:28 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 11:33 +1300
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 11:37 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 11:50 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 14:10 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 05:24 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 15:12 +0200
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 13:13 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 14:44 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 16:38 +0200
                Re: software disenchantment mark.bluemel@gmail.com - 2018-10-11 08:09 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 17:43 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 17:36 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 18:56 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-11 11:54 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 20:09 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 13:10 +0000
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-13 12:57 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 14:27 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 22:03 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 15:56 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 11:30 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 23:34 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-11 16:24 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 01:46 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-11 18:58 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-12 08:50 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 11:12 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 12:55 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 12:10 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 13:29 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 13:06 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 14:30 +0200
                Re: software disenchantment James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-10-12 08:53 -0400
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 15:11 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 13:55 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 15:13 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 16:10 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 15:22 +0000
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-12 09:12 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-13 13:00 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-13 12:52 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-14 08:44 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-13 21:03 +0100
                Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-14 10:13 +1300
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-13 23:02 +0100
                Re: software disenchantment Keith Thompson <kst-u@mib.org> - 2018-10-13 16:47 -0700
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-14 01:05 +0100
                Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-13 18:12 -0700
                Re: software disenchantment Ben Bacarisse <ben.usenet@bsb.me.uk> - 2018-10-14 03:05 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-14 20:14 +0200
                Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-14 11:25 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 13:17 +0000
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 13:16 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 14:36 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 14:25 +0000
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-12 15:55 +0100
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 15:22 +0000
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-12 08:26 -0700
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-12 15:51 +0000
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-13 13:06 +0200
                Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-15 19:30 +0000
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 12:39 +0200
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-12 08:44 +0200
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 13:01 +0200
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 20:41 +0200
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 20:02 +0100
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 22:13 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 13:03 -0500
                Re: software disenchantment "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2018-10-11 11:33 -0700
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 21:04 +0200
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-11 20:15 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-12 13:17 +0200
                Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 13:10 +0000
                Re: software disenchantment BGB <cr88192@hotmail.com> - 2018-10-10 19:22 -0500
                Re: software disenchantment David Brown <david.brown@hesbynett.no> - 2018-10-11 10:58 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 02:37 -0700
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 12:06 +0200
                Re: software disenchantment Malcolm McLean <malcolm.arthur.mclean@gmail.com> - 2018-10-11 04:00 -0700
                Re: software disenchantment Cecil Bayona <cbayona@cbayona.com> - 2018-10-11 13:03 -0500
                Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 19:36 +0100
                Re: software disenchantment Cecil Bayona <cbayona@cbayona.com> - 2018-10-11 15:37 -0500
                Re: software disenchantment Thiago Adams <thiago.adams@gmail.com> - 2018-10-10 14:01 -0700
        Re: software disenchantment Ian Collins <ian-news@hotmail.com> - 2018-10-11 09:02 +1300
      Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-10 19:11 +0000
        Re: software disenchantment David Kleinecke <dkleinecke@gmail.com> - 2018-10-10 13:08 -0700
          Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-11 14:52 +0000
            Re: software disenchantment scott@slp53.sl.home (Scott Lurndal) - 2018-10-11 14:58 +0000
            Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-11 17:19 +0200
              Re: software disenchantment Dan Purgert <dan@djph.net> - 2018-10-12 09:49 +0000
                Re: software disenchantment Wouter Verhelst <w@uter.be> - 2018-10-13 09:30 +0200
                Re: software disenchantment Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-10-15 08:53 +0000
                Re: software disenchantment Dan Purgert <dan@djph.net> - 2018-10-15 09:44 +0000
    Re: software disenchantment Jens Stuckelberger <Jens_Stuckelberger@nowhere.net> - 2018-10-10 13:36 +0000
  Re: software disenchantment "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-10-10 13:51 -0700
    Re: software disenchantment nobody@example.org (Scott) - 2018-10-11 01:53 +0000
    Re: software disenchantment Dan Purgert <dan@djph.net> - 2018-10-11 10:20 +0000
    Re: software disenchantment Bart <bc@freeuk.com> - 2018-10-11 12:53 +0100
      Re: software disenchantment "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-10-11 23:18 -0700

csiph-web