1 // Copyright 2024 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package abi 6 7 import "unsafe" 8 9 // NoEscape hides the pointer p from escape analysis, preventing it 10 // from escaping to the heap. It compiles down to nothing. 11 // 12 // WARNING: This is very subtle to use correctly. The caller must 13 // ensure that it's truly safe for p to not escape to the heap by 14 // maintaining runtime pointer invariants (for example, that globals 15 // and the heap may not generally point into a stack). 16 // 17 //go:nosplit 18 //go:nocheckptr 19 func NoEscape(p unsafe.Pointer) unsafe.Pointer { 20 x := uintptr(p) 21 return unsafe.Pointer(x ^ 0) 22 } 23 24 var alwaysFalse bool 25 var escapeSink any 26 27 // Escape forces any pointers in x to escape to the heap. 28 func Escape[T any](x T) T { 29 if alwaysFalse { 30 escapeSink = x 31 } 32 return x 33 } 34