1 // errorcheck -0 -live -d=eagerwb 2 3 // Copyright 2016 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 // Issue 15747: liveness analysis was marking heap-escaped params live too much, 8 // and worse was using the wrong bitmap bits to do so. 9 10 // TODO(austin): This expects function calls to the write barrier, so 11 // we enable the legacy eager write barrier. Fix this once the 12 // buffered write barrier works on all arches. 13 14 package p 15 16 var global *[]byte 17 18 type Q struct{} 19 20 type T struct{ M string } 21 22 var b bool 23 24 func f1(q *Q, xx []byte) interface{} { // ERROR "live at call to newobject: xx$" "live at call to writebarrierptr: &xx$" "live at entry to f1: xx$" 25 // xx was copied from the stack to the heap on the previous line: 26 // xx was live for the first two prints but then it switched to &xx 27 // being live. We should not see plain xx again. 28 if b { 29 global = &xx // ERROR "live at call to writebarrierptr: &xx$" 30 } 31 xx, _, err := f2(xx, 5) // ERROR "live at call to f2: &xx$" "live at call to writebarrierptr: err.data err.type$" 32 if err != nil { 33 return err 34 } 35 return nil 36 } 37 38 //go:noinline 39 func f2(d []byte, n int) (odata, res []byte, e interface{}) { // ERROR "live at entry to f2: d$" 40 if n > len(d) { 41 return d, nil, &T{M: "hello"} // ERROR "live at call to newobject: d" "live at call to writebarrierptr: d" 42 } 43 res = d[:n] 44 odata = d[n:] 45 return 46 } 47
