languages/go
languages/go
1
0
Fork 0
mirror of https://github.com/golang/go synced 2024-09-15 22:20:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

reflect: add Value.UnsafePointer

Browse source 
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>
This commit is contained in:
Cuong Manh Le 2021-09-18 10:32:22 +07:00
parent 543a513304
commit 4d550727f8
5 changed files with 75 additions and 57 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
src/reflect/all_test.go
View file

@ -3223,11 +3223,11 @@ func (*outer) M() {}
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 (i *InnerInt) M() int {
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 @@ func TestSlice(t *testing.T) {
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 @@ func TestSlice3(t *testing.T) {
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 @@ func verifyGCBitsSlice(t *testing.T, typ Type, cap int, bits []byte) {
// 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.

6
src/reflect/deepequal.go
View file

@ -102,7 +102,7 @@ func deepValueEqual(v1, v2 Value, visited map[visit]bool) bool {
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 @@ func deepValueEqual(v1, v2 Value, visited map[visit]bool) bool {
}
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 @@ func deepValueEqual(v1, v2 Value, visited map[visit]bool) bool {
if v1.Len() != v2.Len() {
return false
}
if v1.Pointer() == v2.Pointer() {
if v1.UnsafePointer() == v2.UnsafePointer() {
return true
}
for _, k := range v1.MapKeys() {

6
src/reflect/set_test.go
View file

@ -79,7 +79,7 @@ func TestImplicitMapConversion(t *testing.T) {
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 @@ func TestImplicitMapConversion(t *testing.T) {
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 @@ func TestImplicitMapConversion(t *testing.T) {
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)
}
}

4
src/reflect/type.go
View file

@ -2666,8 +2666,8 @@ func StructOf(fields []StructField) Type {
{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)
}

94
src/reflect/value.go
View file

@ -1933,44 +1933,10 @@ func (v Value) OverflowUint(x uint64) bool {
// 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 @@ func (v Value) Uint() uint64 {
// 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 @@ func (v Value) UnsafeAddr() uintptr {
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.