The new package "internal/unsafeheader" depends only on "unsafe", and
provides declarations equivalent to reflect.StringHeader and
reflect.SliceHeader but with Data fields of the proper unsafe.Pointer
type (instead of uintptr).
Unlike the types it replaces, the "internal/unsafeheader" package has
a regression test to ensure that its header types remain equivalent to
the declarations provided by the "reflect" package.
Since "internal/unsafeheader" has almost no dependencies, it can be
used in other low-level packages such as "syscall" and "reflect".
This change is based on the corresponding x/sys change in CL 231177.
Fixes#37805
Updates #19367
Change-Id: I7a6d93ef8dd6e235bcab94e7c47270aad047af31
Reviewed-on: https://go-review.googlesource.com/c/go/+/231223
Reviewed-by: Ian Lance Taylor <iant@golang.org>
We already have the ptrdata field in a type, which encodes exactly
the same information that kindNoPointers does.
My problem with kindNoPointers is that it often leads to
double-negative code like:
t.kind & kindNoPointers != 0
Much clearer is:
t.ptrdata == 0
Update #27167
Change-Id: I92307d7f018a6bbe3daca4a4abb4225e359349b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/169157
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It's not safe to do p+x with unsafe if that would point past the
end of the object. (Valid in C, not safe in Go.)
Pass a "whySafe" reason (compiled away) to explain at each
call site why it's safe.
Fixes#21733.
Change-Id: I5da8c25bde66f5c9beac232f2135dcab8e8bf3b1
Reviewed-on: https://go-review.googlesource.com/80738
Reviewed-by: Austin Clements <austin@google.com>
Swapper returns a func that swaps two elements in a slice.
Updates #16721
Change-Id: I7f2287a675c10a05019e02b7d62fb870af31216f
Reviewed-on: https://go-review.googlesource.com/30088
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
