Why does `objc_storeStrong` return id?

[HendrikHuebner]

In the ancient Clang docs it is indeed declared as returning id: https://releases.llvm.org/3.1/tools/clang/docs/AutomaticReferenceCounting.html?utm_source=chatgpt.com#runtime.objc_storeStrong

However, objc4 declares it as void: https://github.com/opensource-apple/objc4/blob/cd5e62a5597ea7a31dccef089317abb3a661c154/runtime/objc-internal.h#L481

And clang does not seem to care about the return value at all: https://github.com/llvm/llvm-project/blob/2c72beb8fe47f93963e575709370d884459012cd/clang/lib/CodeGen/CGObjC.cpp#L2556

This is once again an issue for WebAssembly, which does not tolate signature mismatches unlike native ABIs like x86 or arm.

Is changing the signature of objc_storeStrong in libobjc2 an option? Perhaps only for wasm platforms?

[davidchisnall]

I presume it returned id so that clang could use the result. This could improve code size in debug builds (where clang emits objc_storeStrong) by avoiding the need to spill and reload the value across the call. But if Apple's runtime never did this, then clang almost certainly can't take advantage of it.

The newer docs document it as returning void, so we should probably adopt that.