Web export: add -Zdefault-visibility=hidden#127
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src/toolchain/export-web.md
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| "-C", "link-args=-pthread", # /!\ Read 'Thread support' below regarding this flag | ||
| "-C", "target-feature=+atomics", # /!\ Read 'Thread support' below regarding this flag | ||
| "-C", "link-args=-sSIDE_MODULE=2", | ||
| "-C", "-Zdefault-visibility=hidden", |
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I think you meant this?
| "-C", "-Zdefault-visibility=hidden", | |
| "-Z", "default-visibility=hidden", |
src/toolchain/export-web.md
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| RUSTFLAGS="-C link-args=-pthread \ | ||
| -C target-feature=+atomics \ | ||
| -C link-args=-sSIDE_MODULE=2 \ | ||
| -C -Zdefault-visibility=hidden \ |
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| -C -Zdefault-visibility=hidden \ | |
| -Z default-visibility=hidden \ |
src/toolchain/export-web.md
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| -C link-args=-pthread \ | ||
| -C target-feature=+atomics \ | ||
| -C link-args=-sSIDE_MODULE=2 \ | ||
| -C default-visibility=hidden \ |
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| -C default-visibility=hidden \ | |
| -Z default-visibility=hidden \ |
| A bit of background: The compiled Wasm binary is a _side module_ which is dynamically loaded by Godot's _main module_ at runtime. | ||
| This is very similar to how dynamic libraries and executables work. | ||
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| The [`default-visibility=hidden` flag][rustc-visibility] ensures that symbols of each side module are private to that module. |
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Could this affect user (non-gdext internal) code somehow? If this is the default, how can it be selectively turned off?
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I currently don't see a use case where one wouldn't want that -- it would mean explicitly sharing symbols with other side modules (Godot or extensions) -- and there are better ways to communicate with them (GDExtension itself) 🤔
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I don't think it can be selectively turned off right now, which is unfortunate. There is an RFC, though.
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I still think that the toolchain's behaviour is buggy, I believe normally only #[unsafe(no_mangle)] should be exported like this. As I mentioned in my comment, on x86-64 Linux all non-mangled objects end up as LOCAL.
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| In addition, please note that **godot-rust 0.3 or later** is required to fix this error. | ||
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| 4. `LinkError: WebAssembly.instantiate(): Import #6 "env" "__cpp_exception": tag import requires a WebAssembly.Tag` |
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Wonder if we could also mention something about this bug in this section, but I suppose it doesn't lead to one specific error, rather being undefined behavior / a race condition.
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Thanks a lot @PgBiel! The different formatting and order of Regarding "what if one forgets |
Interesting. Would be nice indeed i possible. More generally, though, I really wish we could just manage those flags for the user. Would be nice if we could figure out a way to set "defaults"... I remember looking into some solution involving |
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See godot-rust/gdext#968 (comment)