reflect: add Value.UnsafePointer
Allowing eliminates a class of possible misuse of unsafe.Pointer, and
allow callers to migrate from Value.Addr and Value.Pointer, thus they
can be now deprecated.
Fixes #40592
Change-Id: I798e507c748922cac5cc1c1971c1b2cc7095a068
Reviewed-on: https://go-review.googlesource.com/c/go/+/350691
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>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/src/reflect/all_test.go b/src/reflect/all_test.go
index 0370906..141cc8f 100644
--- a/src/reflect/all_test.go
+++ b/src/reflect/all_test.go
@@ -3223,11 +3223,11 @@
func TestNestedMethods(t *testing.T) {
typ := TypeOf((*outer)(nil))
- if typ.NumMethod() != 1 || typ.Method(0).Func.Pointer() != ValueOf((*outer).M).Pointer() {
+ if typ.NumMethod() != 1 || typ.Method(0).Func.UnsafePointer() != ValueOf((*outer).M).UnsafePointer() {
t.Errorf("Wrong method table for outer: (M=%p)", (*outer).M)
for i := 0; i < typ.NumMethod(); i++ {
m := typ.Method(i)
- t.Errorf("\t%d: %s %#x\n", i, m.Name, m.Func.Pointer())
+ t.Errorf("\t%d: %s %p\n", i, m.Name, m.Func.UnsafePointer())
}
}
}
@@ -3266,11 +3266,11 @@
func TestEmbeddedMethods(t *testing.T) {
typ := TypeOf((*OuterInt)(nil))
- if typ.NumMethod() != 1 || typ.Method(0).Func.Pointer() != ValueOf((*OuterInt).M).Pointer() {
+ if typ.NumMethod() != 1 || typ.Method(0).Func.UnsafePointer() != ValueOf((*OuterInt).M).UnsafePointer() {
t.Errorf("Wrong method table for OuterInt: (m=%p)", (*OuterInt).M)
for i := 0; i < typ.NumMethod(); i++ {
m := typ.Method(i)
- t.Errorf("\t%d: %s %#x\n", i, m.Name, m.Func.Pointer())
+ t.Errorf("\t%d: %s %p\n", i, m.Name, m.Func.UnsafePointer())
}
}
@@ -3528,11 +3528,11 @@
rv := ValueOf(&xs).Elem()
rv = rv.Slice(3, 4)
- ptr2 := rv.Pointer()
+ ptr2 := rv.UnsafePointer()
rv = rv.Slice(5, 5)
- ptr3 := rv.Pointer()
+ ptr3 := rv.UnsafePointer()
if ptr3 != ptr2 {
- t.Errorf("xs.Slice(3,4).Slice3(5,5).Pointer() = %#x, want %#x", ptr3, ptr2)
+ t.Errorf("xs.Slice(3,4).Slice3(5,5).UnsafePointer() = %p, want %p", ptr3, ptr2)
}
}
@@ -3575,11 +3575,11 @@
rv = ValueOf(&xs).Elem()
rv = rv.Slice3(3, 5, 7)
- ptr2 := rv.Pointer()
+ ptr2 := rv.UnsafePointer()
rv = rv.Slice3(4, 4, 4)
- ptr3 := rv.Pointer()
+ ptr3 := rv.UnsafePointer()
if ptr3 != ptr2 {
- t.Errorf("xs.Slice3(3,5,7).Slice3(4,4,4).Pointer() = %#x, want %#x", ptr3, ptr2)
+ t.Errorf("xs.Slice3(3,5,7).Slice3(4,4,4).UnsafePointer() = %p, want %p", ptr3, ptr2)
}
}
@@ -6818,7 +6818,7 @@
// repeat a bitmap for a small array or executing a repeat in
// a GC program.
val := MakeSlice(typ, 0, cap)
- data := NewAt(ArrayOf(cap, typ), unsafe.Pointer(val.Pointer()))
+ data := NewAt(ArrayOf(cap, typ), val.UnsafePointer())
heapBits := GCBits(data.Interface())
// Repeat the bitmap for the slice size, trimming scalars in
// the last element.
diff --git a/src/reflect/deepequal.go b/src/reflect/deepequal.go
index 94174de..7f1ecb2 100644
--- a/src/reflect/deepequal.go
+++ b/src/reflect/deepequal.go
@@ -102,7 +102,7 @@
if v1.Len() != v2.Len() {
return false
}
- if v1.Pointer() == v2.Pointer() {
+ if v1.UnsafePointer() == v2.UnsafePointer() {
return true
}
// Special case for []byte, which is common.
@@ -121,7 +121,7 @@
}
return deepValueEqual(v1.Elem(), v2.Elem(), visited)
case Ptr:
- if v1.Pointer() == v2.Pointer() {
+ if v1.UnsafePointer() == v2.UnsafePointer() {
return true
}
return deepValueEqual(v1.Elem(), v2.Elem(), visited)
@@ -139,7 +139,7 @@
if v1.Len() != v2.Len() {
return false
}
- if v1.Pointer() == v2.Pointer() {
+ if v1.UnsafePointer() == v2.UnsafePointer() {
return true
}
for _, k := range v1.MapKeys() {
diff --git a/src/reflect/set_test.go b/src/reflect/set_test.go
index a633e6e..566dc7f 100644
--- a/src/reflect/set_test.go
+++ b/src/reflect/set_test.go
@@ -79,7 +79,7 @@
if x != b2 {
t.Errorf("#5 after SetMapIndex(b1, b2): %p (!= %p), %t (map=%v)", x, b2, ok, m)
}
- if p := mv.MapIndex(ValueOf(b1)).Elem().Pointer(); p != uintptr(unsafe.Pointer(b2)) {
+ if p := mv.MapIndex(ValueOf(b1)).Elem().UnsafePointer(); p != unsafe.Pointer(b2) {
t.Errorf("#5 MapIndex(b1) = %#x want %p", p, b2)
}
}
@@ -94,7 +94,7 @@
if x != c2 {
t.Errorf("#6 after SetMapIndex(c1, c2): %p (!= %p), %t (map=%v)", x, c2, ok, m)
}
- if p := mv.MapIndex(ValueOf(c1)).Pointer(); p != ValueOf(c2).Pointer() {
+ if p := mv.MapIndex(ValueOf(c1)).UnsafePointer(); p != ValueOf(c2).UnsafePointer() {
t.Errorf("#6 MapIndex(c1) = %#x want %p", p, c2)
}
}
@@ -110,7 +110,7 @@
if x != b2 {
t.Errorf("#7 after SetMapIndex(b1, b2): %p (!= %p), %t (map=%v)", x, b2, ok, m)
}
- if p := mv.MapIndex(ValueOf(b1)).Pointer(); p != uintptr(unsafe.Pointer(b2)) {
+ if p := mv.MapIndex(ValueOf(b1)).UnsafePointer(); p != unsafe.Pointer(b2) {
t.Errorf("#7 MapIndex(b1) = %#x want %p", p, b2)
}
}
diff --git a/src/reflect/type.go b/src/reflect/type.go
index afb802e..96f589c 100644
--- a/src/reflect/type.go
+++ b/src/reflect/type.go
@@ -2666,8 +2666,8 @@
{Name: "M", Type: ArrayOf(len(methods), TypeOf(methods[0]))},
}))
- typ = (*structType)(unsafe.Pointer(tt.Elem().Field(0).UnsafeAddr()))
- ut = (*uncommonType)(unsafe.Pointer(tt.Elem().Field(1).UnsafeAddr()))
+ typ = (*structType)(tt.Elem().Field(0).Addr().UnsafePointer())
+ ut = (*uncommonType)(tt.Elem().Field(1).Addr().UnsafePointer())
copy(tt.Elem().Field(2).Slice(0, len(methods)).Interface().([]method), methods)
}
diff --git a/src/reflect/value.go b/src/reflect/value.go
index 6bc02c1..a272714 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -1933,44 +1933,10 @@
// If v's Kind is Slice, the returned pointer is to the first
// element of the slice. If the slice is nil the returned value
// is 0. If the slice is empty but non-nil the return value is non-zero.
+//
+// Deprecated: use uintptr(Value.UnsafePointer()) to get the equivalent result.
func (v Value) Pointer() uintptr {
- // TODO: deprecate
- 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()})
+ return uintptr(v.UnsafePointer())
}
// Recv receives and returns a value from the channel v.
@@ -2476,8 +2442,9 @@
// UnsafeAddr returns a pointer to v's data, as a uintptr.
// It is for advanced clients that also import the "unsafe" package.
// It panics if v is not addressable.
+//
+// Deprecated: use uintptr(Value.Addr().UnsafePointer()) to get the equivalent result.
func (v Value) UnsafeAddr() uintptr {
- // TODO: deprecate
if v.typ == nil {
panic(&ValueError{"reflect.Value.UnsafeAddr", Invalid})
}
@@ -2487,6 +2454,57 @@
return uintptr(v.ptr)
}
+// UnsafePointer returns v's value as a unsafe.Pointer.
+// It panics if v's Kind is not Chan, Func, Map, Ptr, Slice, or UnsafePointer.
+//
+// If v's Kind is Func, the returned pointer is an underlying
+// code pointer, but not necessarily enough to identify a
+// single function uniquely. The only guarantee is that the
+// result is zero if and only if v is a nil func Value.
+//
+// If v's Kind is Slice, the returned pointer is to the first
+// element of the slice. If the slice is nil the returned value
+// is nil. If the slice is empty but non-nil the return value is non-nil.
+func (v Value) UnsafePointer() unsafe.Pointer {
+ k := v.kind()
+ switch k {
+ case Ptr:
+ if v.typ.ptrdata == 0 {
+ // Since it is a not-in-heap pointer, all pointers to the heap are
+ // forbidden! See comment in Value.Elem and issue #48399.
+ if !verifyNotInHeapPtr(*(*uintptr)(v.ptr)) {
+ panic("reflect: reflect.Value.UnsafePointer on an invalid notinheap pointer")
+ }
+ return *(*unsafe.Pointer)(v.ptr)
+ }
+ fallthrough
+ case Chan, Map, UnsafePointer:
+ return 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 **(**unsafe.Pointer)(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 p
+
+ case Slice:
+ return (*unsafeheader.Slice)(v.ptr).Data
+ }
+ panic(&ValueError{"reflect.Value.UnsafePointer", v.kind()})
+}
+
// StringHeader is the runtime representation of a string.
// It cannot be used safely or portably and its representation may
// change in a later release.
