Towards eliminating the global ctx variable for lld/wasm

[anutosh491]

The goal is to drop the reset function as pointed here.

For this we can do the following (inspired by changes in lld/ELF & https://maskray.me/blog/2024-11-17-removing-global-state-from-lld)

• Move driver into ctx and add LinkerDriver::ctx

1. f596d82#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88
2. bffb26f#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88R94

• Move Config into ctx and migrate LinkerDriver member functions to use ctx.arg.x instead of
  config->x

1. d904542
2. e1a1f18
3. eba30b3#diff-1a6e8fdd6339ca831ba81ed9fb4f94c42419f91d67c9e16322b71a3e011b42d2

• Add Context aware diagnostic functions

1. 201d760#diff-aab11f6988e1c802cd24d6e9842068288284b0a06366b0121f37493c929bd8e0R55

• Pass ctx to bAlloc/saver/uniqueSaver

1. a626eb2#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88R109
2. 2991a4e#diff-ba5e9bcbcabe54e23f58f9466afb49d9720373eb11b9b3a42ddc2d653b035594

• Miscallaneous like

1. Move symtab into ctx (df0864e#diff-9e4503a72c1e0c0a2743852386d5e9a99574f6e6a25be24160269e729fb1e433)
2. Pass ctx to InputFiles (4986510_
3. etc

• Finally we can get rid of reset and the ctx global variable . Also let Ctx inherit from CommonLinkerContext

1. 73bb022#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88R115
2. 8f238f6

[anutosh491]

@MaskRay I can start resolving these one by one, starting from the first todo
Once I have a green flag from your side and you could confirm if this is the way to go.

Hopefully having separate PRs for each should be the way to go (makes it easier for reviews)

[llvmbot]

@llvm/issue-subscribers-lld-wasm

Author: Anutosh Bhat (anutosh491)

The goal is to drop the [reset](https://github.com//pull/118440#issuecomment-2516296560) function as pointed here.

For this we can do the following (inspired by changes in lld/ELF & https://maskray.me/blog/2024-11-17-removing-global-state-from-lld)

• Move driver into ctx and add LinkerDriver::ctx

1. f596d82#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88
2. bffb26f#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88R94

• Move Config into ctx and migrate LinkerDriver member functions to use ctx.arg.x instead of
  config->x

1. d904542
2. e1a1f18
3. eba30b3#diff-1a6e8fdd6339ca831ba81ed9fb4f94c42419f91d67c9e16322b71a3e011b42d2

• Add Context aware diagnostic functions

1. 201d760#diff-aab11f6988e1c802cd24d6e9842068288284b0a06366b0121f37493c929bd8e0R55

• Pass ctx to bAlloc/saver/uniqueSaver

1. a626eb2#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88R109
2. 2991a4e#diff-ba5e9bcbcabe54e23f58f9466afb49d9720373eb11b9b3a42ddc2d653b035594

• Miscallaneous like

1. Move symtab into ctx (df0864e#diff-9e4503a72c1e0c0a2743852386d5e9a99574f6e6a25be24160269e729fb1e433)
2. Pass ctx to InputFiles (4986510_
3. etc

• Finally we can get rid of reset and the ctx global variable . Also let Ctx inherit from CommonLinkerContext

1. 73bb022#diff-5514d8102381f1f4b47bfb1caf0b7c06bbc3b3d2677c6844d0001eb022b64d88R115
2. 8f238f6

[anutosh491]

cc @MaskRay do you think this approach is fine to get started ?

[anutosh491]

Haven't heard from @MaskRay yet, maybe @sbc100 could get me started ?

[anutosh491]

Hey @sbc100

I was interested in fixing this but haven't heard anything for the same .I did describe what my approach would be in the issue despcription. let me know what y'all think

[sbc100]

I believe some of this work has already landed. See a222d00 and 3792b36.

As for the rest of it, it looks reasonable to me. I would start with the next item on your list and send a PR where we can discuss more.