Hi all,

  I need a little helping hand with dmd on a 32 bit Debian box. I
installed dmd from http://d-apt.sourceforge.net/

i) First trial:

====================
$cat test.d

import std.stdio;
void main() {
   writeln("hello");
}

$ time dmd test.d

real    0m2.355s
user    0m1.652s
sys     0m0.364s

$./test
hello

$ dmd -v test.d | wc -l
84
====================

Seems to be working. My only concern is whether 2.35s for
compiling such a trivial file is normal.

ii) 2nd trial

======================
I installed gdc. Now I get
$ time gdc test.d

real    0m6.286s
user    0m3.856s
sys     0m0.884s
======================

Given the dmd and gdc timings, it seems I am doing something
wrong.

iii) 3rd trial

I installed tango from http://d-apt.sourceforge.net/ I know this
can ruffle feathers. Please assume good faith. I am just trying
to learn from the tango book.

=======================

$ls /usr/include/dmd/tango

core  io  math  net  stdc  sys  text  time  util

$cat test.d

import tango.io.Stdout;

void main() {
   Stdout ("hello").newline;
}

$dmd -I/usr/include/dmd/tango  -v test.d


binary    dmd
version   v2.065
config    /etc/dmd.conf
parse     test
importall test
import    object
(/usr/include/dmd/druntime/import/object.di)
import    tango.io.Stdout       (tango/io/Stdout.d)
test.d(1): Error: module Stdout is in file 'tango/io/Stdout.d'
which cannot be read
import path[0] = /usr/include/dmd/tango
import path[1] = /usr/include/dmd/phobos
import path[2] = /usr/include/dmd/druntime/import


It seems inspite of specifying usr/include/dmd/tango it cannot
import tango.io.Stdout.

Here is my /etc/dmd.conf

[Environment32]
DFLAGS=-I/usr/include/dmd/phobos
-I/usr/include/dmd/druntime/import -L-L/usr/lib/i386-linux-gnu
-L--export-dynamics

What am I doing wrong.

Thanks for the help.

-- Dean

Dean:

>   I need a little helping hand with dmd on a 32 bit Debian box. I
> installed dmd from http://d-apt.sourceforge.net/
>
> i) First trial:
>
> ====================
> $cat test.d
>
> import std.stdio;
> void main() {
>    writeln("hello");
> }
>
> $ time dmd test.d
>
> real    0m2.355s
> user    0m1.652s
> sys     0m0.364s
>
> $./test
> hello
>
> $ dmd -v test.d | wc -l
> 84
> ====================
>
> Seems to be working. My only concern is whether 2.35s for
> compiling such a trivial file is normal.

On a Windows 32 bit that little program compiles in 0.74 seconds (warmed up time) using and old CPU. Modern CPUs should take about 0.5 seconds.

Keep in mind that writeln and std.stdio are lot of stuff. If you use C io functions:

void main() {
    import core.stdc.stdio;

    puts("hello");
}


This compiles in 0.18 seconds (warmed up time) on the same computer with dmd. The difference between 0.74 and 0.18 is more or less a constant if you use std.stdio.


I have also tried this C++ version:

#include <iostream>

int main() {
    std::cout << "hello" << std::endl;
    return 0;
}


With gcc 4.8.0 it takes me 0.48 seconds to compile (warmed up time).

Writeln manages unicode, and is quite more refined than iostream.

Bye,
bearophile

> On a Windows 32 bit that little program compiles in 0.74 seconds (warmed up time) using and old CPU. Modern CPUs should take about 0.5 seconds.

Thanks for checking the timings.... wait I am not alone in using a
32 bit box !

Mine is an Athlon 1045.456 MHz. The minimum of 3 consecutive
compilation runs that I get is 2.3 seconds.

> Keep in mind that writeln and std.stdio are lot of stuff.

Just to be clear I am not complaining dmd is slow. I am just
concerned that I am doing something wrong.

> I have also tried this C++ version:
>
> #include <iostream>
> int main() {
>     std::cout << "hello" << std::endl;
>     return 0;
> }
> With gcc 4.8.0 it takes me 0.48 seconds to compile (warmed up time).

On my box this compiles in 1.2 seconds. So it seems somewhat
consistent (as in 3 times slower for both). I got worried because
I expected dmd to compile "hello world" substantially faster than
g++. I have heard that dmd is instantaneous.


I am still at a loss about tango for D2 problem. Shouldnt
providing the -I option with the path to tango work. Does any
other magic need to happen. I dont know the internal mechanics of
importing modules.

Dean:

> Mine is an Athlon 1045.456 MHz. The minimum of 3 consecutive
> compilation runs that I get is 2.3 seconds.

Then I think your timings could be OK, I am using an old 2.3 GHz CPU.


> On my box this compiles in 1.2 seconds. So it seems somewhat
> consistent (as in 3 times slower for both).

OK.


> I got worried because I expected dmd to compile "hello world"
> substantially faster than g++. I have heard that dmd is instantaneous.

dmd compiles very quickly, but to compile writeln D has to digest a good amount of Phobos code. So you will not see a much larger compilation time if you compile small D programs.


> I am still at a loss about tango for D2 problem.

I think I've never used Tango with dmd.

Bye,
bearophile

On Thursday, 17 July 2014 at 09:32:24 UTC, bearophile wrote:
> Dean:
>
>> Mine is an Athlon 1045.456 MHz.
                           ^^^^
Didn't notice that before hitting send.

>> compilation runs that I get is 2.3 seconds.
> Then I think your timings could be OK, I am using an old 2.3 GHz CPU.

Glad to know that I am not doing something stupid, yet.

> dmd compiles very quickly, but to compile writeln D has to digest a good amount of Phobos code.

Are the reasons for this similar to why C++ STL is not an object
code library ?

>> I am still at a loss about tango for D2 problem.
> I think I've never used Tango with dmd.

Not even sure if its a tango problem. Dmd doesn't seem to be
picking up the path that I specify with -I. Perhaps the mechanics
of module loading is not as simple as I imagine. I initially
thought its a permission problem, but that is not the case.

Dean:

>> dmd compiles very quickly, but to compile writeln D has to digest a good amount of Phobos code.
>
> Are the reasons for this similar to why C++ STL is not an object
> code library ?

The reasons for the large amount of code compiled for a writeln are that: writeln is more powerful, Phobos modules import each other a lot. And several parts of Phobos are not compiled because there are templates everywhere. Take a look at Phobos sources and you will see.

Bye,
bearophile

On Thursday, 17 July 2014 at 10:13:46 UTC, bearophile wrote:
> Dean:
>
>>> dmd compiles very quickly, but to compile writeln D has to digest a good amount of Phobos code.
>>
>> Are the reasons for this similar to why C++ STL is not an object
>> code library ?
>
> The reasons for the large amount of code compiled for a writeln are that: writeln is more powerful, Phobos modules import each other a lot. And several parts of Phobos are not compiled because there are templates everywhere. Take a look at Phobos sources and you will see.
>
> Bye,
> bearophile

Apologies, I wasnt clear. I was talking about the reason behind
compiling the code from source as opposed to linking precompiled
objects. I was speculating wether the reasons are similar to that of STL, i.e. specializing to the type as late as possible.

On 7/17/2014 7:01 PM, Dean wrote:

>
> Not even sure if its a tango problem. Dmd doesn't seem to be
> picking up the path that I specify with -I. Perhaps the mechanics
> of module loading is not as simple as I imagine. I initially
> thought its a permission problem, but that is not the case.

What does your tango source tree look like? Is it a) or b)?

a) /usr/include/dmd/tango/io/Stdout.d
b) /usr/include/dmd/tango/tango/io/Stdout.d

When you pass -I/usr/include/dmd/tango, then it needs to look like b). If it's a), then you should pass -I/usr/include/dmd. The reason is that 'tango' is the top-level package directory. Its *parent* directory needs to be on the import path.

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On Thursday, 17 July 2014 at 11:08:16 UTC, Mike Parker wrote:
> On 7/17/2014 7:01 PM, Dean wrote:
>
>>
>> Not even sure if its a tango problem. Dmd doesn't seem to be
>> picking up the path that I specify with -I. Perhaps the mechanics
>> of module loading is not as simple as I imagine. I initially
>> thought its a permission problem, but that is not the case.
>
> What does your tango source tree look like? Is it a) or b)?
>
> a) /usr/include/dmd/tango/io/Stdout.d
> b) /usr/include/dmd/tango/tango/io/Stdout.d
>
> When you pass -I/usr/include/dmd/tango, then it needs to look like b). If it's a), then you should pass -I/usr/include/dmd. The reason is that 'tango' is the top-level package directory. Its *parent* directory needs to be on the import path.

Hi Mike,

  that was it. Thanks a lot.