bitcode 被废弃了

在 Xcode 14 的发布日志中： https://developer.apple.com/documentation/xcode-release-notes/xcode-14-release-notes

Apple Clang Compiler

Deprecations Starting with Xcode 14, bitcode is no longer required for watchOS and tvOS applications, and the App Store no longer accepts bitcode submissions from Xcode 14.

Xcode no longer builds bitcode by default and generates a warning message if a project explicitly enables bitcode: “Building with bitcode is deprecated. Please update your project and/or target settings to disable bitcode.” The capability to build with bitcode will be removed in a future Xcode release. IPAs that contain bitcode will have the bitcode stripped before being submitted to the App Store. Debug symbols for past bitcode submissions remain available for download. (86118779)

在 Emscripten 3.1.23 的更新日志也有提到： https://github.com/emscripten-core/emscripten/blob/main/ChangeLog.md#3123---092322

Linking of bitcode files using emcc -r + -flto is no longer supported. emcc -r will now always use lld to link to an object file. This matches the behavior of upstream llvm where bitcode linking using lld does not exist. The recommend way to combine bitcode input is to use library files (ar archives). See #13492 for more details.

在上游的 LLVM 15 中，lld 不存在 bitcode 的链接行为了。

至于为什么放弃了 bitcode ，还没有官方的解释。