feat(vm) Add support for iOS

[Connoropolous]

Summary

Is IOS on the roadmap for wasmer anywhere, and if so does it have a predicted timeline?
I noted there is VERY recent support for the new apple silicon chips.

Additional details

I was trying to compile a project with a dependency on (https://github.com/holochain/holochain) (with target aarch64-apple-ios ) which has a dependency currently on wasmer-runtime-core v0.16.2 and discovered that we can't build wasmer-runtime-core for that target.

Holochain uses wasmer for executing apps built on their p2p framework... and I am interested in running those p2p apps in native ios applications.

This was the issue that was popping up when I tried...

error[E0425]: cannot find function `get_fault_info` in this scope
   --> /Users/x/.cargo/registry/src/github.com-1ecc6299db9ec823/wasmer-runtime-core-0.16.2/src/fault.rs:285:21
    |
285 |         let fault = get_fault_info(siginfo as _, ucontext);
    |                     ^^^^^^^^^^^^^^ not found in this scope

[MarkMcCaskey]

Hey @Connoropolous, we hope to run Wasmer pretty much everywhere in the future!

However, iOS in particular is fairly tricky as Apple does not allow JITs in the app store. However it should be possible to use precompiled Wasm modules with Wasmer or execute the Wasm without a JIT.

You might have better luck with Wasmer 1.0.0-alpha* releases of Wasmer / the latest version on master, but I imagine there's likely to be more cases similar to the one you ran into above.

[Connoropolous]

@MarkMcCaskey thanks for the info! On latest releases has it been tried to compile for apple-ios targets, or are you confident from your background knowledge that it won't work? (I will try if you haven't tried, just to see)

[syrusakbary]

The issue is not that it won't work, but that Apple have never approved any app in the store that uses JIT compilation techniques.

However, the JIT restriction might have changed in iOS 14.2 - https://9to5mac.com/2020/11/06/ios-14-2-brings-jit-compilation-support-which-enables-emulation-apps-at-full-performance/

So I'd encourage you to try it out and post here your findings!

[Connoropolous]

My first findings suggest there would need to be PRs put through to make it happen, it's not quite there. Good to hear that Apple could open to this.

This is attempting to compile from version 1.0.0-alpha5
cargo build --release --target x86_64-apple-ios --manifest-path lib/deprecated/runtime/Cargo.toml
and with aarch64-apple-ios

error: unsupported platform
--> /Users/x/code/rsm/wasmer/lib/vm/src/trap/traphandlers.rs:209:21
|
209 | compile_error!("unsupported platform");
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error[E0425]: cannot find function pthread_getattr_np in crate libc
--> /Users/x/code/rsm/wasmer/lib/vm/src/trap/traphandlers.rs:94:19
|
94 | libc::pthread_getattr_np(this_thread, &mut thread_attrs);
| ^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: pthread_getname_np
|
::: /Users/x/.cargo/registry/src/github.com-1ecc6299db9ec823/libc-0.2.73/src/unix/bsd/apple/mod.rs:3393:5
|
3393 | / pub fn pthread_getname_np(
3394 | | thread: ::pthread_t,
3395 | | name: *mut ::c_char,
3396 | | len: ::size_t,
3397 | | ) -> ::c_int;
| |_________________- similarly named function pthread_getname_np defined here

error[E0425]: cannot find function pthread_attr_getstack in crate libc
--> /Users/x/code/rsm/wasmer/lib/vm/src/trap/traphandlers.rs:97:19
|
97 | libc::pthread_attr_getstack(&thread_attrs, &mut stackaddr, &mut stacksize);
| ^^^^^^^^^^^^^^^^^^^^^ help: a function with a similar name exists: pthread_attr_destroy
|
::: /Users/connor/.cargo/registry/src/github.com-1ecc6299db9ec823/libc-0.2.73/src/unix/mod.rs:1089:5
|
1089 | pub fn pthread_attr_destroy(attr: *mut ::pthread_attr_t) -> ::c_int;
| -------------------------------------------------------------------- similarly named function pthread_attr_destroy defined here

error[E0308]: mismatched types
--> /Users/x/code/rsm/wasmer/lib/vm/src/trap/traphandlers.rs:194:52
|
194 | unsafe fn get_pc(cx: *mut libc::c_void) -> *const u8 {
| ------ ^^^^^^^^^ expected *-ptr, found ()
| |
| implicitly returns () as its body has no tail or return expression
|
= note: expected raw pointer *const u8
found unit type ()

error: aborting due to 4 previous errors

[panicfrog]

in the website, i found that the wasmer can run on iOS Android, how to do that?

[kkebo]

@panicfrog You misunderstood about it. It just says that WebAssembly can run on iOS, not Wasmer.

[NathHorrigan]

Hi @Hywan ,

I've seen you've had some activity on this issue.

I've been trying to compile Wasmer to iOS using the dylib engine but having issues with each compiler that I use.

Currently I'm trying LLVM but once I drag the libwasmer.a file to Xcode and run I get the following error. Any ideas?

ld: in /.../example/ios/libwasmer.a(Scalar.cpp.o), archive member 'Scalar.cpp.o' with length 19360 is not mach-o or llvm bitcode for architecture arm64

[Hywan]

Can be kinda relevant #2516.

[syrusakbary]

As of this PR: #2535 we now support iOS on Wasmer master (the version 2.0.1/2.1.0 will be released soon

[afa7789]

https://wasmer.io/posts/wasmer-2.1
https://stackoverflow.com/questions/68963743/how-to-use-wasmer-in-ios