fix Issue 24129 - ImportC: MS-Link cannot handle multiple COMDATs wit…

[WalterBright]

…h the same name

Took me a while to figure out where to put this tweak. Although it is meant just for MS-LINK, I enabled it for all targets to flush out any bugs in it.

[dlang-bot]

Thanks for your pull request, @WalterBright!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	24129	critical	ImportC: MS-Link cannot handle multiple COMDATs with the same name

⚠️⚠️⚠️ Warnings ⚠️⚠️⚠️

• Regression or critical bug fixes should always target the stable branch. Learn more about rebasing to stable or the D release process.

To target stable perform these two steps:

1. Rebase your branch to upstream/stable:

git rebase --onto upstream/stable upstream/master

2. Change the base branch of your PR to stable

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#15585"

[RazvanN7]

[maxhaton]

Does it have to be declared inline? The rest of the compiler has a more (...) global pattern for the global variables.

[PetarKirov]

@WalterBright can we make Csymtab a member variable of the ToSymbol visitor class? If not, why? Perhaps we can move it up the call stack and pass it as a parameter to the visitor constructor, in case there are multiple instances?

[WalterBright]

I prefer to prove that this fix works. Refactoring it then can (and should) be an independent task.

[RazvanN7]

Should we really be fixing linker issues in the compiler?

[WalterBright]

Should we really be fixing linker issues in the compiler?

The main reason DMD (and DMC++) had its own linker was it was easier than concocting endless workarounds for MS-Link bugs.

We can't fix the linker! So what else can we do?

[WalterBright]

Why is this not approved?

[RazvanN7]

There's this comment from @PetarKirov which remains unaddressed.

[WalterBright]

@RazvanN7 it's addressed now.