Unfortunately there are performance issues with
WebAssembly.compileStreaming on iOS. On iOS devices, there is a limited amount of faster memory. Because of this, the engine doesn’t know which kind of memory to compile for until
instantiate is called.
If I understand correctly, for the JSC engine
compileStreaming will just do a memcopy of the .wasm. It’s only when
instantiate is called that the Memory object is created. Then the engine knows whether it will be using the fast memory, or just a normal malloc’d Memory that needs bounds checks. At this point, it can generate the code appropriately.
Because of this, we plan to recommend that all bundlers use
instantiateStreaming instead. Does this cause any issues for webpack?