I've picked up an older project for using D on barebones Win32 as
a "better C".
Thanks to recent advances in DMD (-betterC and -m32mscoff), I
could get a "Hello, world" program on Win32 down to just 438
bytes when compiled. This is without assembly, linker scripts,
custom Phobos/Druntime, or manual post-build tweaks.
-betterC allows stripping things like ModuleInfo, and as of
recently it also strips file/module names used for asserts/range
check errors (which were emitted even in -release mode). A better
alternative would be a DMD equivalent to -fdata-sections, though,
so unneeded variables, constants, and data generated by the
compiler could be garbage-collected by the linker.
-m32mscoff allows using more linkers. Specifically, the Microsoft
Linker and Crinkler, which only understand COFF, can both
generate executables which are much smaller than those created by
The 438-byte "Hello, world" program is achieved using Crinkler,
which is a COFF linker with aggressive compression and header
optimization. It was created for compressing 4K demos.
Without compression on header optimization, you can reach 630
bytes using Unilink, a freeware linker which is compatible with
both COFF and OMF.
The source code is not much to look at, most of the "magic" is in
See samples/01-msgbox for more commentary. The figures above are
The motivation for this project is mostly hack value and
aesthetical (a 500 KB EXE with 5 KB worth of actual functionality
is not pretty).