From 3298c749acc32eca0460f52866d169441eb0e076 Mon Sep 17 00:00:00 2001
From: Cherry Mui <cherryyz@google.com>
Date: Thu, 3 Jun 2021 18:29:05 -0400
Subject: [PATCH] [dev.typeparams] runtime: undo go'd closure argument
 workaround

In CL 298669 we added defer/go wrapping, and, as it is not
allowed for closures to escape when compiling runtime, we worked
around it by rewriting go'd closures to argumentless
non-capturing closures, so it is not a real closure and so not
needed to escape.

Previous CL removes the restriction. Now we can undo the
workaround.

Updates #40724.

Change-Id: Ic7bf129da4aee7b7fdb7157414eca943a6a27264
Reviewed-on: https://go-review.googlesource.com/c/go/+/325110
Trust: Cherry Mui <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
---
 src/runtime/export_test.go | 20 ++++----------------
 src/runtime/mgc.go         | 15 +++++----------
 src/runtime/mgcscavenge.go |  4 ++--
 src/runtime/mgcsweep.go    |  4 ++--
 4 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index fa878c4946..60c06c3f10 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -145,40 +145,28 @@ func RunSchedLocalQueueStealTest() {
 	}
 }
 
-// Temporary to enable register ABI bringup.
-// TODO(register args): convert back to local variables in RunSchedLocalQueueEmptyTest that
-// get passed to the "go" stmts there.
-var RunSchedLocalQueueEmptyState struct {
-	done  chan bool
-	ready *uint32
-	p     *p
-}
-
 func RunSchedLocalQueueEmptyTest(iters int) {
 	// Test that runq is not spuriously reported as empty.
 	// Runq emptiness affects scheduling decisions and spurious emptiness
 	// can lead to underutilization (both runnable Gs and idle Ps coexist
 	// for arbitrary long time).
 	done := make(chan bool, 1)
-	RunSchedLocalQueueEmptyState.done = done
 	p := new(p)
-	RunSchedLocalQueueEmptyState.p = p
 	gs := make([]g, 2)
 	ready := new(uint32)
-	RunSchedLocalQueueEmptyState.ready = ready
 	for i := 0; i < iters; i++ {
 		*ready = 0
 		next0 := (i & 1) == 0
 		next1 := (i & 2) == 0
 		runqput(p, &gs[0], next0)
 		go func() {
-			for atomic.Xadd(RunSchedLocalQueueEmptyState.ready, 1); atomic.Load(RunSchedLocalQueueEmptyState.ready) != 2; {
+			for atomic.Xadd(ready, 1); atomic.Load(ready) != 2; {
 			}
-			if runqempty(RunSchedLocalQueueEmptyState.p) {
-				//println("next:", next0, next1)
+			if runqempty(p) {
+				println("next:", next0, next1)
 				throw("queue is empty")
 			}
-			RunSchedLocalQueueEmptyState.done <- true
+			done <- true
 		}()
 		for atomic.Xadd(ready, 1); atomic.Load(ready) != 2; {
 		}
diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 4585663535..c239fa0f63 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -167,22 +167,17 @@ func gcinit() {
 	lockInit(&work.wbufSpans.lock, lockRankWbufSpans)
 }
 
-// Temporary in order to enable register ABI work.
-// TODO(register args): convert back to local chan in gcenabled, passed to "go" stmts.
-var gcenable_setup chan int
-
 // gcenable is called after the bulk of the runtime initialization,
 // just before we're about to start letting user code run.
 // It kicks off the background sweeper goroutine, the background
 // scavenger goroutine, and enables GC.
 func gcenable() {
 	// Kick off sweeping and scavenging.
-	gcenable_setup = make(chan int, 2)
-	go bgsweep()
-	go bgscavenge()
-	<-gcenable_setup
-	<-gcenable_setup
-	gcenable_setup = nil
+	c := make(chan int, 2)
+	go bgsweep(c)
+	go bgscavenge(c)
+	<-c
+	<-c
 	memstats.enablegc = true // now that runtime is initialized, GC is okay
 }
 
diff --git a/src/runtime/mgcscavenge.go b/src/runtime/mgcscavenge.go
index 7578129f9d..9cb61ed0a6 100644
--- a/src/runtime/mgcscavenge.go
+++ b/src/runtime/mgcscavenge.go
@@ -249,7 +249,7 @@ func scavengeSleep(ns int64) int64 {
 // The background scavenger maintains the RSS of the application below
 // the line described by the proportional scavenging statistics in
 // the mheap struct.
-func bgscavenge() {
+func bgscavenge(c chan int) {
 	scavenge.g = getg()
 
 	lockInit(&scavenge.lock, lockRankScavenge)
@@ -261,7 +261,7 @@ func bgscavenge() {
 		wakeScavenger()
 	}
 
-	gcenable_setup <- 1
+	c <- 1
 	goparkunlock(&scavenge.lock, waitReasonGCScavengeWait, traceEvGoBlock, 1)
 
 	// Exponentially-weighted moving average of the fraction of time this
diff --git a/src/runtime/mgcsweep.go b/src/runtime/mgcsweep.go
index 8fe3a65340..1812644623 100644
--- a/src/runtime/mgcsweep.go
+++ b/src/runtime/mgcsweep.go
@@ -153,13 +153,13 @@ func finishsweep_m() {
 	nextMarkBitArenaEpoch()
 }
 
-func bgsweep() {
+func bgsweep(c chan int) {
 	sweep.g = getg()
 
 	lockInit(&sweep.lock, lockRankSweep)
 	lock(&sweep.lock)
 	sweep.parked = true
-	gcenable_setup <- 1
+	c <- 1
 	goparkunlock(&sweep.lock, waitReasonGCSweepWait, traceEvGoBlock, 1)
 
 	for {