• Andrei Alexandrescu (30/30) Aug 06 2020 So this project has a registration function that associates pointers to
• rikki cattermole (5/5) Aug 06 2020 In theory it should be as simple as setting it in lflags.
• Andrei Alexandrescu (9/16) Aug 06 2020 I did try this:
• rikki cattermole (1/1) Aug 06 2020 https://github.com/dlang/dub/issues/1990
• Andre Pany (9/27) Aug 07 2020 I am not an expert in this area, just thinking loud: dub could

Andrei Alexandrescu <SeeWebsiteForEmail erdani.com> writes:

So this project has a registration function that associates pointers to 
functions to functionality architecture.

The current approach is to have a file, say everything.d, that imports 
all modules in the project and then for each module calls the function 
(inside that module) that carries the registration.

Of course that makes everything.d a large dependency knot that takes 
long to compile and also makes incremental/modular/parallel compilation 
unduly difficult.

This is a classic problem with a classic solution: build a little 
registry and have each module register itself in the shared static 
this() module constructor. The code in each module would go:

shared static this() {
     addRegistration(&myRegistrationFunction);
}

That way everything does not depend on anything, and the onus is on each 
module to register itself. That way modules can be changed (or even 
added!) literally without a need to touch or recompile anything else in 
the project. Neat!

Except, the project is a static library. When linking the library with 
an executable, the linker is motivated to cull unused modules. And for 
good reason. (You don't want to initialize the fpga library in 
hello_world, etc.) So the module finds that each of those 
self-registering modules is not used from the outside (the module 
constructor is beautifully/damnedly self-referential) and eliminates the 
entire module. So no more registration and the scheme doesn't work.

This is another classic problem with a classic solution: when linking 
anything with mylib.a, send the linker the --whole-archive flag just 
before it and the --no-whole-archive flag right after it. (Other OSs 
have similar flags.)

How can I do that in dub?

rikki cattermole <rikki cattermole.co.nz> writes:

In theory it should be as simple as setting it in lflags.

But you will need to test it, as I'm not sure if it'll propagate upwards 
to where you need it.

If that doesn't work, having dub automatically handle registration 
functions would be a nice feature request to have.

Andrei Alexandrescu <SeeWebsiteForEmail erdani.com> writes:

On 8/6/20 2:19 PM, rikki cattermole wrote:
 In theory it should be as simple as setting it in lflags.
 
 But you will need to test it, as I'm not sure if it'll propagate upwards 
 to where you need it.
 
 If that doesn't work, having dub automatically handle registration 
 functions would be a nice feature request to have.

I did try this:

lflags "--whole-archive" "/path/to/libmylib.a" "--no-whole-archive"

But that doesn't work, presumably because the command line contains the 
same library before these flags. So I assume the first occurrence is 
taken and the second ignored.

As an aside, it is very irritating that dub multiplies the flags for 
some reason, e.g. -defaultlib=libphobos2.so appears literally 30 times 
in the same command line. Similar for other flags.

rikki cattermole <rikki cattermole.co.nz> writes:

https://github.com/dlang/dub/issues/1990

Andre Pany <andre s-e-a-p.de> writes:

On Thursday, 6 August 2020 at 19:31:01 UTC, Andrei Alexandrescu 
wrote:
 On 8/6/20 2:19 PM, rikki cattermole wrote:
 In theory it should be as simple as setting it in lflags.
 
 But you will need to test it, as I'm not sure if it'll 
 propagate upwards to where you need it.
 
 If that doesn't work, having dub automatically handle 
 registration functions would be a nice feature request to have.

 I did try this:

 lflags "--whole-archive" "/path/to/libmylib.a" 
 "--no-whole-archive"

 But that doesn't work, presumably because the command line 
 contains the same library before these flags. So I assume the 
 first occurrence is taken and the second ignored.

 As an aside, it is very irritating that dub multiplies the 
 flags for some reason, e.g. -defaultlib=libphobos2.so appears 
 literally 30 times in the same command line. Similar for other 
 flags.

I am not an expert in this area, just thinking loud: dub could 
recognize the `--whole-archive`, `--no-whole-archive` pattern in 
lflags and add it also to the first occurrence of the lib file in 
the command line.

This should be a rather simple fix?

Kind regards
Andre