cmd/compile: remove gc programs from stack frame objects
This is a two-pronged approach. First, try to keep large objects
off the stack frame. Second, if they do manage to appear anyway,
use straight bitmasks instead of gc programs.
Generally probably a good idea to keep large objects out of stack frames.
But particularly keeping gc programs off the stack simplifies
runtime code a bit.
This CL sets the limit of most stack objects to 131072 bytes (on 64-bit archs).
There can still be large objects if allocated by a late pass, like order, or
they are required to be on the stack, like function arguments.
But the size for the bitmasks for these objects isn't a huge deal,
as we have already have (probably several) bitmasks for the frame
liveness map itself.
Change-Id: I6d2bed0e9aa9ac7499955562c6154f9264061359
Reviewed-on: https://go-review.googlesource.com/c/go/+/542815 Reviewed-by: David Chase <drchase@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Cherry Mui <cherryyz@google.com>