WebAssembly calling convention impl incorrectly uses make_indirect_byval()

[bjorn3]

It should use make_indirect() instead. It seems like LLVM ignores sarg on WebAssembly, so it happens to work out fine in the end with the LLVM backend at least, but it is still incorrect per https://github.com/WebAssembly/tool-conventions/blob/main/BasicCABI.md.

For those unaware the difference between the two is that make_indirect() will pass a pointer to the argument somewhere, while make_indirect_byval() is supposed to store the argument at a fixed location on the stack.

[workingjubilee]

For those unaware the difference between the two is that make_indirect() will pass a pointer to the argument somewhere, while make_indirect_byval() is supposed to store the argument at a fixed location on the stack.

So one is pass_by_pointer and the one is pass_by_stack_location?

[bjorn3]

Yes. The former sets the pass mode to PassMode::Indirect { on_stack: false, ... } while the latter sets it to PassMode::Indirect { on_stack: true, ... }. I believe the on_stack field used to be called byval too, but I changed it a couple of years ago as byval is pretty confusing.