mirror of
https://github.com/golang/go
synced 2024-11-05 18:36:08 +00:00
e3e0122ae2
Replace various implementations of inlining prevention with "go:noinline" Change-Id: Iac90895c3a62d6f4b7a6c72e11e165d15a0abfa4 Reviewed-on: https://go-review.googlesource.com/16510 Reviewed-by: Keith Randall <khr@golang.org> Run-TryBot: Todd Neal <todd@tneal.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
78 lines
1.7 KiB
Go
78 lines
1.7 KiB
Go
// 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.
|
|
|
|
// The liveness code used to say that, in func g, s was live
|
|
// starting at its declaration, because it appears to have its
|
|
// address taken by the closure (different s, but the parser
|
|
// gets slightly confused, a separate bug). The liveness analysis
|
|
// saw s as having its address taken but the register optimizer
|
|
// did not. This mismatch meant that s would be marked live
|
|
// (and therefore initialized) at the call to f, but the register optimizer
|
|
// would optimize away the initialization of s before f, causing the
|
|
// garbage collector to use unused data.
|
|
// The register optimizer has been changed to respect the
|
|
// same "address taken" flag that the liveness analysis uses,
|
|
// even if it cannot see any address being taken in the actual
|
|
// machine code. This is conservative but keeps the two consistent,
|
|
// which is the most important thing.
|
|
|
|
package main
|
|
|
|
import "runtime"
|
|
|
|
//go:noinline
|
|
func f() interface{} {
|
|
runtime.GC()
|
|
return nil
|
|
}
|
|
|
|
//go:noinline
|
|
func g() {
|
|
var s interface{}
|
|
_ = func() {
|
|
s := f()
|
|
_ = s
|
|
}
|
|
s = f()
|
|
useiface(s)
|
|
useiface(s)
|
|
}
|
|
|
|
//go:noinline
|
|
func useiface(x interface{}) {
|
|
}
|
|
|
|
//go:noinline
|
|
func h() {
|
|
var x [16]uintptr
|
|
for i := range x {
|
|
x[i] = 1
|
|
}
|
|
|
|
useint(x[0])
|
|
useint(x[1])
|
|
useint(x[2])
|
|
useint(x[3])
|
|
}
|
|
|
|
//go:noinline
|
|
func useint(x uintptr) {
|
|
}
|
|
|
|
func main() {
|
|
// scribble non-zero values on stack
|
|
h()
|
|
// call function that used to let the garbage collector
|
|
// see uninitialized stack values; it will see the
|
|
// nonzero values.
|
|
g()
|
|
}
|
|
|
|
func big(x int) {
|
|
if x >= 0 {
|
|
big(x - 1)
|
|
}
|
|
}
|