runtime: use one more address bit for tagged pointers
We use one extra bit to placate systems which simulate amd64 binaries on
an arm64 host. Allocated arm64 addresses could be as high as 1<<48-1,
which would be invalid if we assumed 48-bit sign-extended addresses.
(Note that this does not help the other way around, simluating arm64
on amd64, but we don't have that problem at the moment.)
Fixes #69255
Change-Id: Iace17a5d41a65e34abf201d03d8b0ff6f7bf1150
Reviewed-on: https://go-review.googlesource.com/c/go/+/700515 Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Michael Knyszek <mknyszek@google.com>