mirror of
https://github.com/golang/go
synced 2024-11-25 15:17:58 -07:00
e24977d231
The next CL will remove the -G flag, effectively hard-coding it to its current default (-G=3). Change-Id: Ib4743b529206928f9f1cca9fdb19989728327831 Reviewed-on: https://go-review.googlesource.com/c/go/+/388534 Reviewed-by: Keith Randall <khr@golang.org> Trust: Matthew Dempsky <mdempsky@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
69 lines
1.6 KiB
Go
69 lines
1.6 KiB
Go
// run
|
|
|
|
// Copyright 2021 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.
|
|
|
|
package main
|
|
|
|
import (
|
|
"fmt"
|
|
"unsafe"
|
|
)
|
|
|
|
// size returns the size of type T
|
|
func size[T any](x T) uintptr {
|
|
return unsafe.Sizeof(x)
|
|
}
|
|
|
|
// size returns the alignment of type T
|
|
func align[T any](x T) uintptr {
|
|
return unsafe.Alignof(x)
|
|
}
|
|
|
|
type Tstruct[T any] struct {
|
|
f1 T
|
|
f2 int
|
|
}
|
|
|
|
// offset returns the offset of field f2 in the generic type Tstruct
|
|
func (r *Tstruct[T]) offset() uintptr {
|
|
return unsafe.Offsetof(r.f2)
|
|
}
|
|
|
|
func main() {
|
|
v1 := int(5)
|
|
if got, want := size(v1), unsafe.Sizeof(v1); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
if got, want := align(v1), unsafe.Alignof(v1); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
|
|
v2 := "abc"
|
|
if got, want := size(v2), unsafe.Sizeof(v2); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
if got, want := align(v2), unsafe.Alignof(v2); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
|
|
var v3 Tstruct[int]
|
|
if got, want := unsafe.Offsetof(v3.f2), unsafe.Sizeof(v1); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
|
|
var v4 Tstruct[interface{}]
|
|
var v5 interface{}
|
|
if got, want := unsafe.Offsetof(v4.f2), unsafe.Sizeof(v5); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
|
|
if got, want := v3.offset(), unsafe.Offsetof(v3.f2); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
if got, want := v4.offset(), unsafe.Offsetof(v4.f2); got != want {
|
|
panic(fmt.Sprintf("got %d, want %d", got, want))
|
|
}
|
|
}
|