github.com/noisysockets/netstack@v0.6.0/pkg/gohacks/noescape_unsafe.go (about)

     1  // Copyright 2023 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package gohacks
    16  
    17  import (
    18  	"unsafe"
    19  )
    20  
    21  // Noescape hides a pointer from escape analysis. Noescape is the identity
    22  // function but escape analysis doesn't think the output depends on the input.
    23  // Noescape is inlined and currently compiles down to zero instructions.
    24  // USE CAREFULLY!
    25  //
    26  // Noescape is copy/pasted from Go's runtime/stubs.go:noescape(), and is valid
    27  // as of Go 1.20. It is possible that this approach stops working in future
    28  // versions of the toolchain, at which point `p` may still escape.
    29  //
    30  //go:nosplit
    31  func Noescape(p unsafe.Pointer) unsafe.Pointer {
    32  	x := uintptr(p)
    33  	return unsafe.Pointer(x ^ 0)
    34  }