Re: PSA: Passing linker flags on the command line

[Floh]

Thanks for the explanation, I wasn't aware that wasm-ld flags change so 
frequently.

> Do you have projects that rely on faking support for certain flags?  i.e. 
are you directly affected by this change

>From what I'm seeing in my own build scripts, no. But I maintain a build 
system wrapper (https://floooh.github.io/fips/) which also has helper 
commands for setting up a project-local emscripten SDK, so it might be that 
users of this build system wrapper are affected in their projects if they 
use -Wl for some reason, I think it's unlikely though.

Cheers!

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Re: PSA: Passing linker flags on the command line

['Sam Clegg' via emscripten-discuss]

On Fri, Mar 27, 2020 at 7:05 AM Floh  wrote:

> Apologies if this has already been discussed or asking an obviously dumb
> question, but shouldn't emcc be able to remove any unsupported options
> before passing them to wasm-ld without having to manually maintain a list
> of unsupported options, since emcc and wasm-ld are essentially
> "version-locked"?
>
>
That is the alternative approach and, as I say, we have gone back and forth
on this a couple of times now.The current approach has been frustrating
for me over time because the full whitelist of supported flags isn't
maintained correctly.  As wasm-ld evolves new flags get added but
emscripten's list is out-of-date.  So we get bug reports where a new flag
might be useful for debugging but the advice of adding `-Wl,-some-flag` to
aid debugging doesn't work because `some-flag` gets filtered out.

Secondly, in most cases, the correct solution is to stop passing bad linker
flags.  I'd prefer to only ignore flags which are impossible/hard to remove
from a given build system, or that we want to pretend to support.  I'd
rather not pretend to support arbitrary flags that we don't even know
about.

Finally I believe the blacklist, of flags we what "fake" support for should
not evolve over time and should be fixed (after an initial period I don't
expect it to change).

Do you have projects that rely on faking support for certain flags?  i.e.
are you directly affected by this change?

cheers,
sam



> On Thursday, 26 March 2020 02:45:52 UTC+1, Sam Clegg wrote:
>>
>> After going back and forth on this issue I'm hoping to once again allow
>> arbitrary flags to be passed to the linker (wasm-ld) via the command line
>> (-Wl,xxx):  https://github.com/emscripten-core/emscripten/pull/10747.
>>
>> This means that some people will see linker errors because they (or thier
>> build systems) pass flags via `-Wl,xxx` that wasm-ld doesn't handle.  If
>> you encounter such errors you have we have two possible solutions for you:
>>
>> 1. Remove the offending flag from the linker command.
>> 2. Add it to the list of flags that emscripten will ignore not not pass
>> onto the linker (`UNSUPPORTED_LLD_FLAGS`).
>>
>> Hopefully with a combination of these two solutions the fallout of this
>> change should be minimal.
>>
>> cheers,
>> sam
>>
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> .
>

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Re: PSA: Passing linker flags on the command line

[Floh]

Apologies if this has already been discussed or asking an obviously dumb 
question, but shouldn't emcc be able to remove any unsupported options 
before passing them to wasm-ld without having to manually maintain a list 
of unsupported options, since emcc and wasm-ld are essentially 
"version-locked"?

On Thursday, 26 March 2020 02:45:52 UTC+1, Sam Clegg wrote:
>
> After going back and forth on this issue I'm hoping to once again allow 
> arbitrary flags to be passed to the linker (wasm-ld) via the command line 
> (-Wl,xxx):  https://github.com/emscripten-core/emscripten/pull/10747.
>
> This means that some people will see linker errors because they (or thier 
> build systems) pass flags via `-Wl,xxx` that wasm-ld doesn't handle.  If 
> you encounter such errors you have we have two possible solutions for you:
>
> 1. Remove the offending flag from the linker command.
> 2. Add it to the list of flags that emscripten will ignore not not pass 
> onto the linker (`UNSUPPORTED_LLD_FLAGS`).
>
> Hopefully with a combination of these two solutions the fallout of this 
> change should be minimal.
>
> cheers,
> sam
>

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PSA: Passing linker flags on the command line

['Sam Clegg' via emscripten-discuss]

After going back and forth on this issue I'm hoping to once again allow
arbitrary flags to be passed to the linker (wasm-ld) via the command line
(-Wl,xxx):  https://github.com/emscripten-core/emscripten/pull/10747.

This means that some people will see linker errors because they (or thier
build systems) pass flags via `-Wl,xxx` that wasm-ld doesn't handle.  If
you encounter such errors you have we have two possible solutions for you:

1. Remove the offending flag from the linker command.
2. Add it to the list of flags that emscripten will ignore not not pass
onto the linker (`UNSUPPORTED_LLD_FLAGS`).

Hopefully with a combination of these two solutions the fallout of this
change should be minimal.

cheers,
sam

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