Object size?

[kinke]

On Wednesday, 13 March 2024 at 17:40:52 UTC, Andy Valencia wrote:
> On Saturday, 2 March 2024 at 04:33:02 UTC, Andy Valencia wrote:
>> ...But the executable size is enormous.  For 405 statements, 
>> it has a text size of 712k bytes.  Whoof.  Is this normal?  
>> I'm using ldc2 version 1.30.0.
>
> I've played with this some more; this code:
>
> import std.stdio : writefln;
>
> void
> main(in string[] argv)
> {
>     writefln("%s: %d thingies\n", argv[0], 123);
> }
>
> results in 252k of text size in the executable.  It seems like 
> there's some sort of combinatoric explosion going on behind the 
> scenes?
>
> Andy

This isn't LDC-specific and regularly comes up as beginner's 
topic (in general forums, try a search). One thing is that 
druntime and Phobos are linked statically by default (with 
official LDC packages at least; distro versions might not); with 
LDC, use `-link-defaultlib-shared` to link the shared variants. 
That's a pretty constant offset though, so for tiny hello-world 
programs, it might seem huge, but rest assured, it doesn't go on 
like this when the program becomes fleshier.

The 2nd thing is that templates can easily lead to an explosion 
of code. Phobos' std.format is a prime and well-known example of 
that, sadly. If you use `-vcg-ast` for compiling your little .d, 
the compiler will generate a `*.d.cg` file with the instantiated 
templates. You'll see that it's almost 20k lines (~430 KB of 
source code).