tree 5749caac9c0f9214aaa44479a6a8a0b6a3052b1b
parent 433566b436b75ee8aac8c47d37c3965e89749aa4
author Cherry Zhang <cherryyz@google.com> 1546463013 -0500
committer Cherry Zhang <cherryyz@google.com> 1546896814 +0000

bridge: mark write barrier functions GC leaf

Set "gc-leaf-function" attribute for the write barrier
functions. The backend understands this attribute and does not
treats the call sites as statepoints.
(llvm/lib/Transforms/Utils/Local.cpp, callsGCLeafFunction)
This makes the write barriers cheaper (avoid spillings), and
also makes it easier to remove write barriers for stack writes
(not in this CL).

Change-Id: Id5b97275b99c8717d3b9c095231ee0f6e09fe00c
Reviewed-on: https://go-review.googlesource.com/c/156558
Reviewed-by: Than McIntosh <thanm@google.com>