reflect: restore Value.Pointer implementation
CL 350691 added Value.UnsafePointer and make Value.Pointer call it
internally. It has a downside that Value.Pointer can now eligible to be
inlined, thus making un-intentional side effect, like the test in
fixedbugs/issue15329.go becomes flaky.
This CL restore Value.Pointer original implementation, pre CL 350691,
with the deprecation TODO removed.
Fixes #49067
Change-Id: I735af182f8e729294333ca906ffc062f477cfc99
Reviewed-on: https://go-review.googlesource.com/c/go/+/356949
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
diff --git a/src/reflect/value.go b/src/reflect/value.go
index 1d385f6..63faa04 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -1936,7 +1936,42 @@
//
// Deprecated: use uintptr(Value.UnsafePointer()) to get the equivalent result.
func (v Value) Pointer() uintptr {
- return uintptr(v.UnsafePointer())
+ k := v.kind()
+ switch k {
+ case Ptr:
+ if v.typ.ptrdata == 0 {
+ // Handle pointers to go:notinheap types directly,
+ // so we never materialize such pointers as an
+ // unsafe.Pointer. (Such pointers are always indirect.)
+ // See issue 42076.
+ return *(*uintptr)(v.ptr)
+ }
+ fallthrough
+ case Chan, Map, UnsafePointer:
+ return uintptr(v.pointer())
+ case Func:
+ if v.flag&flagMethod != 0 {
+ // As the doc comment says, the returned pointer is an
+ // underlying code pointer but not necessarily enough to
+ // identify a single function uniquely. All method expressions
+ // created via reflect have the same underlying code pointer,
+ // so their Pointers are equal. The function used here must
+ // match the one used in makeMethodValue.
+ f := methodValueCall
+ return **(**uintptr)(unsafe.Pointer(&f))
+ }
+ p := v.pointer()
+ // Non-nil func value points at data block.
+ // First word of data block is actual code.
+ if p != nil {
+ p = *(*unsafe.Pointer)(p)
+ }
+ return uintptr(p)
+
+ case Slice:
+ return (*SliceHeader)(v.ptr).Data
+ }
+ panic(&ValueError{"reflect.Value.Pointer", v.kind()})
}
// Recv receives and returns a value from the channel v.
