Re: Trivial program size inflation

[RVP <rvp%SDF.ORG@localhost>]

On Fri, 30 Jun 2023, Mouse wrote:

> Based on something at work, I was looking at executable sizes.  I
> eventually tried a program stripped about as far down as I could:
>
> int main(void);
> int main(void)
> {
> return(0);
> }
>
> and built it -static.  size on the resulting binary:
> [...]
> amd64, 9.0_STABLE (ftp.n.o):
>
>   text    data     bss     dec     hex filename
> 562318   29064 2176416 2767798  2a3bb6 main
>
> 12K to do nothing is bad enough (I'm going to be looking at why it's
> that big).  149K is even more disturbing (I'll be looking at that too).
> But over half a meg of text and two megs of BSS?  To do nothing?
> Surely something is wrong somewhere.

You need to look at the CRT stuff in /usr/src/lib/csu/ to figure this
out. A lot of initialization and set-up has to be done to get to the
point of calling main(): Calling the libc init routine--which pulls in
malloc, which brings in pthreads (stub or real code). Now you have all
the stuff needed to bring in malloc and stdio coming in: system calls
for those (write, mmap), and the functions these all rely on: strlen(),
strcmp(), ...

Not to forget the code for C++ support. And, of course even static
binaries may call dlopen() and friends. So that dl*() and the ELF bits
right there.

If you want to slim your static binary down, use a different libc first :)

-RVP