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go/pointer/testdata/chanreflect.go
Alan Donovan 2299ac6bf3 go.tools/pointer: make sole callsite available to intrinsics in non-shared contours.
This information can be used to specialize such calls, e.g.
- report location of unsound calls (done for reflect.NewAt)
- exploit argument information (done for constant 'dir' parameter to reflect.ChanOf)

+ tests.

R=crawshaw
CC=golang-dev
https://golang.org/cl/14517046
2013-10-09 12:41:55 -04:00

75 lines
2.2 KiB
Go

// +build ignore
package main
import "reflect"
// Test of channels with reflection.
var a, b int
func chanreflect1() {
ch := make(chan *int, 0) // @line cr1make
crv := reflect.ValueOf(ch)
crv.Send(reflect.ValueOf(&a))
print(crv.Interface()) // @types chan *int
print(crv.Interface().(chan *int)) // @pointsto makechan@cr1make:12
print(<-ch) // @pointsto main.a
}
func chanreflect2() {
ch := make(chan *int, 0)
ch <- &b
crv := reflect.ValueOf(ch)
r, _ := crv.Recv()
print(r.Interface()) // @types *int
print(r.Interface().(*int)) // @pointsto main.b
}
func chanOfRecv() {
// MakeChan(<-chan) is a no-op.
t := reflect.ChanOf(reflect.RecvDir, reflect.TypeOf(&a))
print(reflect.Zero(t).Interface()) // @types <-chan *int
print(reflect.MakeChan(t, 0).Interface().(<-chan *int)) // @pointsto
print(reflect.MakeChan(t, 0).Interface().(chan *int)) // @pointsto
}
func chanOfSend() {
// MakeChan(chan<-) is a no-op.
t := reflect.ChanOf(reflect.SendDir, reflect.TypeOf(&a))
print(reflect.Zero(t).Interface()) // @types chan<- *int
print(reflect.MakeChan(t, 0).Interface().(chan<- *int)) // @pointsto
print(reflect.MakeChan(t, 0).Interface().(chan *int)) // @pointsto
}
func chanOfBoth() {
t := reflect.ChanOf(reflect.BothDir, reflect.TypeOf(&a))
print(reflect.Zero(t).Interface()) // @types chan *int
ch := reflect.MakeChan(t, 0)
print(ch.Interface().(chan *int)) // @pointsto <alloc in reflect.MakeChan>
ch.Send(reflect.ValueOf(&b))
ch.Interface().(chan *int) <- &a
r, _ := ch.Recv()
print(r.Interface().(*int)) // @pointsto main.a | main.b
print(<-ch.Interface().(chan *int)) // @pointsto main.a | main.b
}
var unknownDir reflect.ChanDir // not a constant
func chanOfUnknown() {
// Unknown channel direction: assume all three.
// MakeChan only works on the bi-di channel type.
t := reflect.ChanOf(unknownDir, reflect.TypeOf(&a))
print(reflect.Zero(t).Interface()) // @types <-chan *int | chan<- *int | chan *int
print(reflect.MakeChan(t, 0).Interface()) // @types chan *int
}
func main() {
chanreflect1()
chanreflect2()
chanOfRecv()
chanOfSend()
chanOfBoth()
chanOfUnknown()
}