cmd/compile: catch and report nowritebarrier violations later

Prior to this CL, the SSA backend reported violations
of the //go:nowritebarrier annotation immediately.
This necessitated emitting errors during SSA compilation,
which is not compatible with a concurrent backend.

Instead, check for such violations later.
We already save the data required to do a late check
for violations of the //go:nowritebarrierrec annotation.
Use the same data, and check //go:nowritebarrier at the same time.

One downside to doing this is that now only a single
violation will be reported per function.
Given that this is for the runtime only,
and violations are rare, this seems an acceptable cost.

While we are here, remove several 'nerrors != 0' checks
that are rendered pointless.

Updates #15756
Fixes #19250 (as much as it ever can be)

Change-Id: Ia44c4ad5b6fd6f804d9f88d9571cec8d23665cb3
Reviewed-on: https://go-review.googlesource.com/38973
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This commit is contained in:
Josh Bleecher Snyder 2017-03-30 11:40:06 -07:00
parent ca33e10971
commit 0323895cc0
7 changed files with 3 additions and 31 deletions

View file

@ -124,7 +124,6 @@ func (d DummyFrontend) Logf(msg string, args ...interface{}) { d.t.Logf(msg, arg
func (d DummyFrontend) Log() bool { return true }
func (d DummyFrontend) Fatalf(_ src.XPos, msg string, args ...interface{}) { d.t.Fatalf(msg, args...) }
func (d DummyFrontend) Error(_ src.XPos, msg string, args ...interface{}) { d.t.Errorf(msg, args...) }
func (d DummyFrontend) Warnl(_ src.XPos, msg string, args ...interface{}) { d.t.Logf(msg, args...) }
func (d DummyFrontend) Debug_checknil() bool { return false }
func (d DummyFrontend) Debug_wb() bool { return false }