modernc.org/gc@v1.0.1-0.20240304020402-f0dba7c97c2b/testdata/errchk/test/fixedbugs/bug320.go (about)

     1  // run
     2  
     3  // Copyright 2011 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  package main
     8  
     9  func main() {
    10  	c := make(chan int, 1)
    11  	dummy := make(chan int)
    12  	v := 0x12345678
    13  	for i := 0; i < 10; i++ {
    14  		// 6g had a bug that caused select to pass &t to
    15  		// selectrecv before allocating the memory for t,
    16  		// which caused non-deterministic crashes.
    17  		// This test looks for the bug by checking that the
    18  		// value received actually ends up in t.
    19  		// If the allocation happens after storing through
    20  		// whatever garbage &t holds, the later reference
    21  		// to t in the case body will use the new pointer and
    22  		// not see the received value.
    23  		v += 0x1020304
    24  		c <- v
    25  		select {
    26  		case t := <-c:
    27  			go func() {
    28  				f(t)
    29  			}()
    30  			escape(&t)
    31  			if t != v {
    32  				println(i, v, t)
    33  				panic("wrong values")
    34  			}
    35  		case dummy <- 1:
    36  		}
    37  	}
    38  }
    39  
    40  func escape(*int) {
    41  }
    42  
    43  func f(int) {
    44  }
    45