ForkOn 20/03/2020 22:15, Charles Bailey wrote:
> I have been trying to determine why the executable files produced by
> MinGW are much larger than I would expect, even for small, simple,
> console-mode programs. I tried an experiment with what is probably
> the smallest possible C program. Just one line:>
> int main(void) {return 0;}
For me, cross-compiling this with mingw32-gcc-9.2.0, and the upcoming
(yet-to-be-published) mingwrt-5.3.1, yields a 20480 byte executable:
$ echo 'int main(void){return 0;}' | mingw32-gcc -s -xc -
$ ls -l a.exe
-rwxr-xr-x 1 keith keith 20480 Mar 23 18:49 a.exe
> When I compile this with TCC I get a .exe file that is just 1,536
> bytes. With gcc from MinGW I get a .exe that is 42,035 bytes long.
> Executing the strip command on it to remove debug symbols brings it
> down to 19,470 bytes, which is still more than 12 times the size of
> the TCC-produced file.
So, comparable to my experience, then; (with mingw32-gcc-8.2.0, and
mingwrt-5.2.3, I see 19456 bytes).
> [...snip...]
>
> What is all that extra stuff that MinGW is inserting? Why is it
> referencing tons of functions that I'm not even using?
Eli has already answered this, but some further explanation may be merited:
* The DLL imports, on which you seem to be focused, actually
have a negligible effect on executable size; the dominant
contribution is from MinGW's more comprehensive, more robust,
and predominantly statically linked run-time startup -- and
perhaps to a lesser extent, shutdown -- code.
* The size of the executable may be reduced, at the cost of
additional DLL dependencies, by _more_ dynamic linking; for
example, libmingwex may be dynamically linked, (supported
since mingwrt-5.0, I have libmingwex.dll.a in ./mingwrt/):
$ echo 'int main(void){return 0;}' |
mingw32-gcc -s -xc - -L ./mingwrt/
$ ls -l a.exe
-rwxr-xr-x 1 keith keith 11776 Mar 23 19:14 a.exe
> Are there some gcc options I can specify to eliminate that extra
> stuff?
Yes, but using them is far from trivial: consult GCC documentation for
-nostdlib, and related options, but note that if you use them, you will
likely need to write your own startup code.
--
Regards,
Keith.
Public key available from keys.gnupg.net
Key fingerprint: C19E C018 1547 DE50 E1D4 8F53 C0AD 36C6 347E 5A3F
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