On Wednesday, 30 December 2015 at 09:43:32 UTC, Rainer Schuetze
wrote:
I noticed something similar recently when compiling a C file
with /Gy, see
https://github.com/D-Programming-Language/druntime/pull/1446#issuecomment-160880021
The compiler puts all functions into COMDATs, but they are all
still linked in if only a single symbol is referenced, even if
linked with /OPT:REF.
So I suspect this is not an issue with dmd, but the Microsoft
linker. I still wonder whether the approach to use "function
level linking" works at all for Win64.
> I noticed by looking at some object file dumps that dmd puts
each
> function into its own section, but data symbols, like
initializers, are
> all merged into the same section. Could this be the root
issue?
Having all data in a single section misses some possible
optimizations, and it might be the reason for the behavior in
your case (you can check this with "dumpbin /all objectfile"),
but the issue above does not contain any data.
So if I understand this correctly the microsoft linker only
strips unused comdats, otherwise always the entire object file
gets pulled in?
For me stripping of individual data symbols not working is
actually a good thing, if it doesn't work, I can't break it. ;-)
