cmd/internal/obj/wasm: use 64-bit instructions for indirect calls
Currently, on Wasm, an indirect call is compiled to
// function index = PC>>16, PC is already on stack
I32WrapI64
I32Const $16
ShrU
// set PC_B to 0
...
// actual call
CallIndirect
Specifically, the function index is extracted from bits 16-31 of
the "PC". When there are more than 65536 functions, this will
overflow and wrap around, causing wrong function being called.
This CL changes it to use 64-bit operations to extract the
function index from the "PC", so there are enough bits to for it.
For #64856.
Change-Id: I83c11db4b78cf66250e88ac02a82bd13730a8914
Reviewed-on: https://go-review.googlesource.com/c/go/+/567896
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>