How does K WASM plan to support memory64 proposal specifical

Question

How does K WASM plan to support memory64 proposal specifically current unsafe wasi interop apis where pointer is UInt Will it be similar to K N with 2 different targets or no

Oleg Yukhnevich · Answer

< Svyatoslav Kuzmich JB > any idea on this

Svyatoslav Kuzmich [JB] · Answer

Current thoughts is to keep the default memory as 32 bit and add support for declaring and importing exporting additional memories via multi memory proposal They could be either 32 or 64 bit Current unsafe APIs can t express this We ll need to come up with a separate flexible low level API

Svyatoslav Kuzmich [JB] · Answer

Hopefully we won t need separate targets

Oleg Yukhnevich · Answer

let believe in it slightly smiling face thought introducing separate targets like we have with native is also will be ok from first sight this looks similar to f e iosArm32 and iosArm64 BTW rust now has wasm32 with different variants per emscripten and wasi and wasm64 <https doc rust lang org rustc platform support html> Im not writing in rust just researching

Svyatoslav Kuzmich [JB] · Answer

K Wasm unlike K N and Rust doesn t use linear memory for its own allocations Memory is used primarily to interoperate with others who use it and depending on what other modules use we could support both memory types at the same time in a single program

Svyatoslav Kuzmich [JB] · Answer

Current sketch ``` stdlib Can only be implemented by empty top level objects with special annotations interface WasmMemory32 interface WasmMemory64 fun lt reified T WasmMemory32 gt loadInt ptr Pointer32 Int fun lt reified T WasmMemory64 gt storeInt ptr Pointer64 value Int ``` ``` app WasmImport otherModule memory object MyImportedMemory32 WasmMemory32 WasmMemoryLimits minPages = 10 maxPages = 20 object MyMemory64 WasmMemory64 fun copyIntBetweenMemories into Pointer32 from Pointer64 storeInt lt MyImportedMemory32 gt into loadInt lt MyMemory64 gt from ```

Svyatoslav Kuzmich [JB] · Answer

Of course you can create a separation of platforms in user space by choosing a single memory of needed size in each platfrom and making new expect actual ed pointer type

Oleg Yukhnevich · Answer

Sounds interesting and from first sight is super cool will see how it will go Though I would prefer an API with explicit provinding of object instead of type if possible Like WasmMemory32 loadInt ptr Generics are not so easy to propagate when you want to provide some abstractions over it

Svyatoslav Kuzmich [JB] · Answer

These are just thoughts that we ll have to validate indeed slightly smiling face We ll bikeshed the syntax and names for sure But we ll want to make sure that at the lowest level each load knows it s memory because memory index is an immediate in Wasm We could make a less efficient version of first class memories on top of that

Oleg Yukhnevich · Answer

Sound good Will try to keep my ffi up to date with all latest changes