Link: Add natvis file support

[The-King-of-Toasters]

This PR the ability to include Natvis files into a module's PDB using Compile.addObjectFile. This is eventually passed to the linker via the -NATVIS:[file] flag. Fixes: #19646.

This is my first PR that touches the compiler, so review by people working in that area would be great.

Features:

• Link natvis files for executables.
• Include natvis files specified by any dependency using Compile.linkLibrary.
• Create a set of visualisations for the language & standard library and add them to every PDB by default.

Reasons for Inclusion

• Enhances the ability for the Zig build system to be used to build existing C/C++ projects on Windows.
• Improves the debugging experience for Zig devs on windows, which is already an underserved market.
• Doesn't modify/bloat the code as it only add a named stream to PDBs.

Issues

There is no way to add visualizers for slices as they have square brackets in their type name, which isn't allowed for C++ types. This is an issue the Rust devs ran into and AFAIK still hasn't been fixed. Note that it is still possible to do (char*)buf.ptr,[buf.len]s8 for a []u8 slice when in the debugger.

Some types like packed structs/comptime known enums are lowered to their integer representation when debugging, and these base types cannot be selected for visualization.

[The-King-of-Toasters]

@kubkon Could you put this on your review queue? I don't want the pr to get deleted due to being a draft for a month :x.

[andrewrk]

closing 30+ days old draft

[kubkon]

@kubkon Could you put this on your review queue? I don't want the pr to get deleted due to being a draft for a month :x.

Oh no, I'm so sorry for not reviewing your PR on time - your PR slipped under my radar! Having said that though, I do not feel qualified at reviewing it since 1) I do not really use Windows on a daily basis, and 2) I have no idea what natvis actually is. If I did implement support for natvis in our self-hosted COFF linker, then I would be in a much better position to review, but we are far away from that I think given the state COFF linker is in.

[The-King-of-Toasters]

The issue at the top has more info but TL;DR it's way to add custom visualisations for types when run using a Microsoft debugger (WinDbg, Visual Studio, VSCode). You define them in XML files (yes, I know) and the linker adds it as a stream in a PDB. AFAICT we don't even produce PDBs in self-hosted so this only works when using the LLVM linker (with the -NATVIS flag).

This was mainly me hacking around the linking code so don't feel too bad.