compiler: record pointer var values to remove write barriers
Record when a local pointer variable is set to a value such that
indirecting through the pointer does not require a write barrier. Use
that to eliminate write barriers when indirecting through that local
pointer variable. Only keep this information per-block, so it's not
all that applicable.
This reduces the number of write barriers generated when compiling the
runtime package from 553 to 524.
The point of this is to eliminate a bad write barrier in the bytes
function in runtime/print.go. Mark that function nowritebarrier so
that the problem does not recur.
Reviewed-by: Cherry Zhang <firstname.lastname@example.org>
4 files changed