GeezerVison

Supersedes #549.

Summary

An iOS app running on an Apple silicon Mac ("Designed for iPad") crashes at boot with ReferenceError: UIApplicationDidFinishLaunchingNotification is not defined (see #549 for the lldb evidence).

The root cause is the bundle path, not the lookup. On device builds SymbolLoader::resolveModule opens system frameworks from /System/Library/Frameworks. On a Mac, UIKit and the other iOS-only frameworks live under /System/iOSSupport/System/Library/Frameworks. The /System/Library path either has no bundle (Catalyst on macOS 15, which then falls back to dlsym(RTLD_DEFAULT)), or, on Designed for iPad, a bundle that resolves none of the iOS symbols.

This PR makes resolveModule try the iOSSupport bundle first when isMacCatalystApp / isiOSAppOnMac is true. Frameworks shared with macOS (Foundation, CoreGraphics, …) aren't under iOSSupport, so they fall back to /System/Library/Frameworks as before. The simulator and iOS device paths are unchanged.

Why not a dlsym(RTLD_DEFAULT) fallback (#549)

• It picks up same-named symbols from unrelated images. In a Catalyst process I compared the module bundle lookup with the global dlsym for all 23,631 functions and variables in a real app's metadata. Every mismatch had the bundle returning the declaring framework and the global search returning something else:

  • 293 OpenGLES gl* functions → desktop OpenGL.framework/libGL.dylib
  • 6 AddressBook constants → PassKitCore; ReplayKit SCStreamErrorDomain → ScreenCaptureKit; plus a few more in zippered frameworks

  OpenGLES and AddressBook are iOSSupport frameworks, so a fallback (and today's Catalyst behaviour) binds those calls to the wrong library.

• It leaves the bad bundle in place for ensureModule. ensureModule runs on every method/property availability check while prototypes are built. A bundle that can't load is retried on each call: about 73 µs per attempt in a local measurement, plus an os_log_error line.

Verification

• ./run_tests.sh --temp-sim: 1864 specs, 0 failures, 11 skipped. The simulator build doesn't compile the new branch, so this covers the restructured bundle creation only.
• SymbolLoader.mm compiles for iphoneos, Mac Catalyst and visionOS with -Werror=unguarded-availability(-new).
• Catalyst probe, all 271 iOS SDK frameworks:
  • modules with no bundle: 78 → 37 (the remaining ones don't exist on macOS and still use the dlsym fallback)
  • no framework that loaded before fails to load now
• Catalyst probe, all 23,631 metadata functions/variables: 0 symbols that resolved before are lost with the new lookup.
• Not verified: a real "My Mac (Designed for iPad)" run. iOS-platform binaries can't be launched from a terminal, so that needs a check from someone with a Designed-for-iPad build (the fix(runtime): resolve system symbols when an iOS app runs on a Mac #549 repro app would do).

Summary by CodeRabbit

• Bug Fixes
  • Improved system framework resolution on Mac Catalyst and supported iOS apps running on Mac, with a fallback to the existing lookup when the preferred location is unavailable.