SwiftSDK: Remove hardcoded WASI sysroot path derivation

[kateinoigakukun]

Remove hardcoded WASI sysroot path derivation just for wasi-sysroot embedded in toolchains

Motivation:

The previous implementation assumed there is $TOOLCHAIN_ROOT/share/wasi-sysroot when --triple wasm32-unknown-wasi is passed, but this is no longer the case with the deprecation of the Wasm toolchain installation in favor of Swift SDKs.

Due to this unnecessary branch, when --triple wasm32-unknown-wasi is passed together with --swift-sdk, --swift-sdk is just ignored: #8465

Modifications:

This change removes the hardcoded path derivation for the WASI sysroot from the SwiftSDK.deriveTargetSwiftSDK method.

Result:

When --triple wasm32-unknown-wasi is passed without --swift-sdk, no user visible change and they will keep getting the following:

error: emit-module command failed with exit code 1 (use -v to see invocation)
<unknown>:0: warning: libc not found for 'wasm32-unknown-wasi'; C stdlib may be unavailable
<unknown>:0: error: unable to load standard library for target 'wasm32-unknown-wasi'

When --triple wasm32-unknown-wasi is passed together with --swift-sdk, --triple is ignored and --swift-sdk is respected.

[kateinoigakukun]

@swift-ci test

[jakepetroules]

Thanks! Small clarification...

When --triple wasm32-unknown-wasi is passed together with --swift-sdk, --triple is ignored and --swift-sdk is respected.

What do you mean "--triple is ignored"? Swift SDKs can support multiple triples, so it's supposed to be supported to pass both --swift-sdk and --triple at the same time. Or do you simply mean it's ignored because that Swift SDK just so happens to support only one triple, which just so happens to be the same as the given value in this case?

[jakepetroules]

This also seems like it'd be a good candidate for 6.1.2 if possible.

[kateinoigakukun]

@jakepetroules

Swift SDKs can support multiple triples

Yes, Swift SDK format itself allows supporting multiple triples, but the current SwiftPM's implementation does not respect the value passed to --triple but just use --swift-sdk value when selecting a Swift SDK. See #7973 for more details

I have a plan to make a follow-up fix for it separately later.

[jakepetroules]

@jakepetroules

Swift SDKs can support multiple triples

Yes, Swift SDK format itself allows supporting multiple triples, but the current SwiftPM's implementation does not respect the value passed to --triple but just use --swift-sdk value when selecting a Swift SDK. See #7973 for more details

I have a plan to make a follow-up fix for it separately later.

Got it, thanks for clarifying.

[jakepetroules]

@swift-ci test windows

[kateinoigakukun]

swiftlang/sourcekit-lsp#2107
@swift-ci test

[MaxDesiatov]

swiftlang/sourcekit-lsp#2107
@swift-ci test macos

[MaxDesiatov]

Thanks!

[MaxDesiatov]

@swift-ci test self hosted windows

[kateinoigakukun]

Ah, we had to merge swiftlang/sourcekit-lsp#2107 before this...