On Monday, 16 November 2015 at 08:15:39 UTC, Walter Bright wrote:
On 11/15/2015 8:44 PM, bitwise wrote:
https://issues.dlang.org/show_bug.cgi?id=15342
DMD emits all functions as COMDAT on OSX.
I'm guessing this was originally a workaround of some
kind...does anybody know
the story?
Thanks,
Bit
It enables:
1. the linker to remove duplicates (happens with templates and
other things)
2. the linker to remove unreferenced COMDATs
I understand what it's for, but it's incorrect behaviour to have
_all_ functions being emitted as comdat. Non-template functions
shouldn't be coalesced in this way. If you compile the code
example in the bug report with *any* compiler other than DMD/OSX,
the example will fail as described, with a linker error. The
example compares dmd/osx with gcc/osx, but the code will also
fail with ldc/osx. And although I don't have time to check, I'm
pretty sure it will fail with dmd/win as well.
If you look at the code I cited, this is obviously a hack:
<glue.c#L866-L870>
[...]
#if TARGET_OSX
s->Sclass = SCcomdat;
#else
s->Sclass = SCglobal;
#endif
for (Dsymbol *p = fd->parent; p; p = p->parent) {
if (p->isTemplateInstance()) {
s->Sclass = SCcomdat;
break;
}
}
[...]
Bit
