syncs: start working on mutex debugging, registrationbradfitz/mutex_debug

Updates #17852

Change-Id: Ib1b634eedd30cc4006bc1b39aa8d479d37c5f1f2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/syncs/mutex.go b/syncs/mutex.go
index 8034e1712..78342ffc9 100644
--- a/syncs/mutex.go
+++ b/syncs/mutex.go
@@ -7,6 +7,10 @@ package syncs
 
 import "sync"
 
+// MutexDebugging indicates whether the "ts_mutex_debug" build tag is set
+// and mutex debugging is enabled.
+const MutexDebugging = false
+
 // Mutex is an alias for sync.Mutex.
 //
 // It's only not a sync.Mutex when built with the ts_mutex_debug build tag.
@@ -20,4 +24,14 @@ type RWMutex = sync.RWMutex
 // RequiresMutex declares the caller assumes it has the given
 // mutex held. In non-debug builds, it's a no-op and compiles to
 // nothing.
-func RequiresMutex(mu *sync.Mutex) {}
+func RequiresMutex(mu *Mutex) {}
+
+func RegisterMutex(mu *Mutex, name string) {}
+
+// ForkJoinGo is like go fn() but indicates that the goroutine
+// is part of a fork-join parallelism pattern.
+//
+// This compiles to just "go fn()" in non-debug builds.
+func ForkJoinGo(fn func()) {
+	go fn()
+}