On Saturday, 15 December 2012 at 18:00:58 UTC, H. S. Teoh wrote:
On Sat, Dec 15, 2012 at 06:31:17PM +0100, RenatoUtsch wrote:
On Saturday, 15 December 2012 at 17:05:59 UTC, Peter Alexander
wrote:
>On Saturday, 15 December 2012 at 16:55:39 UTC, Russel Winder
>wrote:
>>A quick straw poll. Do people prefer to have all sources
>>compiled
>>in a single compiler call, or (more like C++) separate
>>compilation
>>of each object followed by a link call.
>
>Single compiler call is easier for small projects, but I worry
>about compile times for larger projects...
Yes, I'm writing a build system for D (that will be pretty damn
good, I think, it has some interesting new concepts), and
compiling
each source separately to an object, and then linking
everything
will allow easily to make the build parallel, dividing the
sources
to compile in various threads. Or the compiler already does
that if
I pass all source files in one call?
[...]
I find that the current front-end (common to dmd, gdc, ldc)
tends to
work better when passed multiple source files at once. It tends
to be
faster, presumably because it only has to parse
commonly-imported files
once, and also produces smaller object/executable sizes --
maybe due to
fewer duplicated template instantiations? I'm not sure of the
exact
reasons, but this behaviour appears consistent throughout dmd
and gdc,
and I presume also ldc (I didn't test that). So based on this,
I'd lean
toward compiling multiple files at once.
Yeah, I did read about this somewhee.
However, in very large project, clearly this won't work very
well. If it
takes half an hour to build the entire system, it makes the
code -
compile - test cycle very slow, which reduces programmer
productivity.
So perhaps one possible middle ground would be to link packages
separately, but compile all the sources within a single package
at once.
Presumably, if the project is properly organized, recompiling a
single
package won't take too long, and has the perk of optimizing for
size
within packages. This will probably also map to SCons easily,
since
SCons builds per-directory.
T
Well, the idea is good. Small projects usually don't have much
packages, so there will be just a few compiler calls. And
compiling files concurrently will only have a meaningful efect if
the project is large, and a large project will have a lot of
packages.
Maybe adding an option to choose between compiling all sources at
once, per package, or per source. For example, in development and
debug builds the compilation is per file or package, but in
release builds all sources are compiled at once, or various
packages at once.
This way release builds will take advantage of this behavior that
the frontend has, but developers won't have productivity issues.
And, of couse, the behaviour will not be fixed, the devs that are
using the build system will choose that.
