codekingpro/portable-devtools

1// run2 3// Copyright 2014 The Go Authors. All rights reserved.4// Use of this source code is governed by a BSD-style5// license that can be found in the LICENSE file.6 7// Test finalizers work for tiny (combined) allocations.8 9package main10 11import (12	"runtime"13	"time"14)15 16func main() {17	// Does not work on gccgo due to partially conservative GC.18	// Try to enable when we have fully precise GC.19	if runtime.Compiler == "gccgo" {20		return21	}22	const N = 10023	finalized := make(chan int32, N)24	for i := 0; i < N; i++ {25		x := new(int32) // subject to tiny alloc26		*x = int32(i)27		// the closure must be big enough to be combined28		runtime.SetFinalizer(x, func(p *int32) {29			finalized <- *p30		})31	}32	runtime.GC()33	count := 034	done := make([]bool, N)35	timeout := time.After(5*time.Second)36	for {37		select {38		case <-timeout:39			println("timeout,", count, "finalized so far")40			panic("not all finalizers are called")41		case x := <-finalized:42			// Check that p points to the correct subobject of the tiny allocation.43			// It's a bit tricky, because we can't capture another variable44			// with the expected value (it would be combined as well).45			if x < 0 || x >= N {46				println("got", x)47				panic("corrupted")48			}49			if done[x] {50				println("got", x)51				panic("already finalized")52			}53			done[x] = true54			count++55			if count > N/10*9 {56				// Some of the finalizers may not be executed,57				// if the outermost allocations are combined with something persistent.58				// Currently 4 int32's are combined into a 16-byte block,59				// ensure that most of them are finalized.60				return61			}62		}63	}64}65