1 files changed, 0 insertions, 134 deletions
diff --git a/src/pkg/sync/waitgroup.go b/src/pkg/sync/waitgroup.go
deleted file mode 100644
index 4c64dca39..000000000
--- a/src/pkg/sync/waitgroup.go
+++ /dev/null
@@ -1,134 +0,0 @@
-// Copyright 2011 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package sync
-
-import (
-	"sync/atomic"
-	"unsafe"
-)
-
-// A WaitGroup waits for a collection of goroutines to finish.
-// The main goroutine calls Add to set the number of
-// goroutines to wait for.  Then each of the goroutines
-// runs and calls Done when finished.  At the same time,
-// Wait can be used to block until all goroutines have finished.
-type WaitGroup struct {
-	m       Mutex
-	counter int32
-	waiters int32
-	sema    *uint32
-}
-
-// WaitGroup creates a new semaphore each time the old semaphore
-// is released. This is to avoid the following race:
-//
-// G1: Add(1)
-// G1: go G2()
-// G1: Wait() // Context switch after Unlock() and before Semacquire().
-// G2: Done() // Release semaphore: sema == 1, waiters == 0. G1 doesn't run yet.
-// G3: Wait() // Finds counter == 0, waiters == 0, doesn't block.
-// G3: Add(1) // Makes counter == 1, waiters == 0.
-// G3: go G4()
-// G3: Wait() // G1 still hasn't run, G3 finds sema == 1, unblocked! Bug.
-
-// Add adds delta, which may be negative, to the WaitGroup counter.
-// If the counter becomes zero, all goroutines blocked on Wait are released.
-// If the counter goes negative, Add panics.
-//
-// Note that calls with positive delta must happen before the call to Wait,
-// or else Wait may wait for too small a group. Typically this means the calls
-// to Add should execute before the statement creating the goroutine or
-// other event to be waited for. See the WaitGroup example.
-func (wg *WaitGroup) Add(delta int) {
-	if raceenabled {
-		_ = wg.m.state // trigger nil deref early
-		if delta < 0 {
-			// Synchronize decrements with Wait.
-			raceReleaseMerge(unsafe.Pointer(wg))
-		}
-		raceDisable()
-		defer raceEnable()
-	}
-	v := atomic.AddInt32(&wg.counter, int32(delta))
-	if raceenabled {
-		if delta > 0 && v == int32(delta) {
-			// The first increment must be synchronized with Wait.
-			// Need to model this as a read, because there can be
-			// several concurrent wg.counter transitions from 0.
-			raceRead(unsafe.Pointer(&wg.sema))
-		}
-	}
-	if v < 0 {
-		panic("sync: negative WaitGroup counter")
-	}
-	if v > 0 || atomic.LoadInt32(&wg.waiters) == 0 {
-		return
-	}
-	wg.m.Lock()
-	if atomic.LoadInt32(&wg.counter) == 0 {
-		for i := int32(0); i < wg.waiters; i++ {
-			runtime_Semrelease(wg.sema)
-		}
-		wg.waiters = 0
-		wg.sema = nil
-	}
-	wg.m.Unlock()
-}
-
-// Done decrements the WaitGroup counter.
-func (wg *WaitGroup) Done() {
-	wg.Add(-1)
-}
-
-// Wait blocks until the WaitGroup counter is zero.
-func (wg *WaitGroup) Wait() {
-	if raceenabled {
-		_ = wg.m.state // trigger nil deref early
-		raceDisable()
-	}
-	if atomic.LoadInt32(&wg.counter) == 0 {
-		if raceenabled {
-			raceEnable()
-			raceAcquire(unsafe.Pointer(wg))
-		}
-		return
-	}
-	wg.m.Lock()
-	w := atomic.AddInt32(&wg.waiters, 1)
-	// This code is racing with the unlocked path in Add above.
-	// The code above modifies counter and then reads waiters.
-	// We must modify waiters and then read counter (the opposite order)
-	// to avoid missing an Add.
-	if atomic.LoadInt32(&wg.counter) == 0 {
-		atomic.AddInt32(&wg.waiters, -1)
-		if raceenabled {
-			raceEnable()
-			raceAcquire(unsafe.Pointer(wg))
-			raceDisable()
-		}
-		wg.m.Unlock()
-		if raceenabled {
-			raceEnable()
-		}
-		return
-	}
-	if raceenabled && w == 1 {
-		// Wait must be synchronized with the first Add.
-		// Need to model this is as a write to race with the read in Add.
-		// As a consequence, can do the write only for the first waiter,
-		// otherwise concurrent Waits will race with each other.
-		raceWrite(unsafe.Pointer(&wg.sema))
-	}
-	if wg.sema == nil {
-		wg.sema = new(uint32)
-	}
-	s := wg.sema
-	wg.m.Unlock()
-	runtime_Semacquire(s)
-	if raceenabled {
-		raceEnable()
-		raceAcquire(unsafe.Pointer(wg))
-	}
-}