On Monday, 18 November 2019 at 19:35:13 UTC, Sebastiaan Koppe
wrote:
Kinke made some changes in dub to facilitate separate linking
for ldc. I am not aware of all the details but the major
benefit is that it allows cross compilation with dub and ldc.
Yeah, definitely useful if you want to link in, say, a C-borne
wasm
binary.
Because of the separate linking the --no-as-needed turned up.
As far as I can see it is only needed when compiling for linux.
Which brings up the question, why linux? Aren't we compiling
for wasm?
Well yes. But that is just the way things worked up until now,
ldc and dub just pick the host machine.
Luckily there is the new dub `--arch` argument that can take a
llvm triple, in our case wasm32-unknown-unknown-wasm. This
causes dub not to add the `--no-as-needed`.
That was news to me - I thought everything was always being
compiled to WASM.
Except, that it also passes the triple upwards the dependency
tree. Now all the dependencies of spasm get compiled targeting
wasm. This is a good thing, except that the optional package
which spasm depends on fails to compile with it. There is a
newer version that fixes the configuration, but that one fails
because of the `from.std` import idiom (it imports the std
package from phobos which doesn't recognise wasm and fails with
"Unknown OS").
I have sometimes thought that perhaps a static assert isn't the
best thing to use for unimplemented features in Phobos, precisely
because of this issue. A @disabled function stub would serve
better, unless I'm missing something.
In the meantime I am going to make a PR for the optional
package to avoid the `from.std` idiom. Although I might end up
playing whack-a-mole here, as there might be more dependencies
that need a fix now.
"ending up"? If it's like what getting Phobos to work has been
for me, you're continuing the game, not ending up playing it ;D.
Another workaround that you can use right now is by adding the
`--build-mode=allAtOnce` argument to dub. It effectively gets
you the old behaviour. It is what I am using in my CI to get it
to go green again.
Do not hurry more than you want -I already got my
extract-dub-failure workaround working.
