Re: Re: size of executable

[Rich Felker <dalias@libc.org>]

On Mon, Aug 12, 2019 at 05:55:28PM +0100, Jorge Almeida wrote:
> On Mon, Aug 12, 2019 at 5:48 PM Jorge Almeida <jjalmeida@gmail.com> wrote:
> >
> 
> > with gcc-8.3.0 on x86_64. Could someone check the following hello.c
> > and see what size you get?
> > I get 16768 bytes (not stripped) and 12324 (stripped).
> > Note that I'm not even using printf.
> >
> > Thanks
> >
> > #include <unistd.h>
> > int main(int argc, char* argv[]){
> >  write(1, "Hello, bloated world...\n", 24);
> > }
> 
> Sorry, I forgot to add the compile options. In attachement, due to
> Gmail interface being what it is.

> gcc -static -Os -march=native -fomit-frame-pointer -pipe -Wall  -Werror=pedantic  -Werror=implicit-function-declaration -pedantic -pedantic-errors -mpreferred-stack-boundary=4 -falign-functions=1 -falign-jumps=1 -falign-loops=1 -fno-unwind-tables -fdata-sections -ffunction-sections -Wl,--gc-sections -fno-asynchronous-unwind-tables -fstrict-aliasing -Wstrict-aliasing=2 -Wno-unused-function -std=c11 hello.c
> 
> Stripping:
> 
> strip -s a.out
> strip -S --strip-unneeded --remove-section=.note.gnu.gold-version --remove-section=.comment --remove-section=.note --remove-section=.note.gnu.build-id --remove-section=.note.ABI-tag --remove-section=.eh_frame --remove-section=.eh_frame_ptr -R .note -R .comment -R .note.GNU-stack a.out
> sstrip a.out

This is a binutils regression from a dubious anti-ROP feature, -z
separate-code. Add -Wl,-z,noseparate-code and it will go away.

FYI musl-cross-make has been updated to change the default back in
toolchains it builds.

Rich