Initial commit: Go 1.23 release state

test/tinyfin.go

@@ -0,0 +1,64 @@
+// run
+
+// Copyright 2014 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.
+
+// Test finalizers work for tiny (combined) allocations.
+
+package main
+
+import (
+	"runtime"
+	"time"
+)
+
+func main() {
+	// Does not work on gccgo due to partially conservative GC.
+	// Try to enable when we have fully precise GC.
+	if runtime.Compiler == "gccgo" {
+		return
+	}
+	const N = 100
+	finalized := make(chan int32, N)
+	for i := 0; i < N; i++ {
+		x := new(int32) // subject to tiny alloc
+		*x = int32(i)
+		// the closure must be big enough to be combined
+		runtime.SetFinalizer(x, func(p *int32) {
+			finalized <- *p
+		})
+	}
+	runtime.GC()
+	count := 0
+	done := make([]bool, N)
+	timeout := time.After(5*time.Second)
+	for {
+		select {
+		case <-timeout:
+			println("timeout,", count, "finalized so far")
+			panic("not all finalizers are called")
+		case x := <-finalized:
+			// Check that p points to the correct subobject of the tiny allocation.
+			// It's a bit tricky, because we can't capture another variable
+			// with the expected value (it would be combined as well).
+			if x < 0 || x >= N {
+				println("got", x)
+				panic("corrupted")
+			}
+			if done[x] {
+				println("got", x)
+				panic("already finalized")
+			}
+			done[x] = true
+			count++
+			if count > N/10*9 {
+				// Some of the finalizers may not be executed,
+				// if the outermost allocations are combined with something persistent.
+				// Currently 4 int32's are combined into a 16-byte block,
+				// ensure that most of them are finalized.
+				return
+			}
+		}
+	}
+}