x/tools/go/analysis/passes/unsafeptr: stricter reporting

The unsafe.Pointer safety rules have three separate rules allowing
conversion of uintptr to unsafe.Pointer:

(3) allows converting unsafe.Pointer to uintptr, performing
arithmetic, and converting back;

(5) allows converting the results from calling
reflect.Value.{Pointer,UnsafeAddr} to unsafe.Pointer; and

(6) allows converting the Data field of reflect.{Slice,String}Header
to unsafe.Pointer.

Notably, these are three separate rules, and they're not allowed to be
arbitrarily mixed. For example, this is not allowed:

    unsafe.Pointer(v.UnsafeAddr() + x) // BAD

It needs to instead be written as:

    unsafe.Pointer(uintptr(unsafe.Pointer(v.UnsafeAddr())) + x)

(For further explanation on why this is necessary, see
https://github.com/google/go-cmp/issues/167#issuecomment-546093202.)

This CL brings cmd/vet's unsafeptr check inline with the
unsafe.Pointer rules and cmd/compile's implementation thereof.

Change-Id: I1844e0f71dcc8fb7aafacc144b86cc80a2b83b42
Reviewed-on: https://go-review.googlesource.com/c/tools/+/248191
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Trust: Matthew Dempsky <mdempsky@google.com>
2 files changed
tree: 25e0db6a0767c6a0bad3f6f089de581d0779fef3
  1. .gitattributes
  2. .gitignore
  3. .prettierrc
  4. AUTHORS
  5. CONTRIBUTING.md
  6. CONTRIBUTORS
  7. LICENSE
  8. PATENTS
  9. README.md
  10. benchmark/
  11. blog/
  12. cmd/
  13. codereview.cfg
  14. container/
  15. cover/
  16. go.mod
  17. go.sum
  18. go/
  19. godoc/
  20. gopls/
  21. imports/
  22. internal/
  23. playground/
  24. present/
  25. refactor/
  26. txtar/
README.md

Go Tools

This subrepository holds the source for various packages and tools that support the Go programming language.

Some of the tools, godoc and vet for example, are included in binary Go distributions.

Others, including the Go guru and the test coverage tool, can be fetched with go get.

Packages include a type-checker for Go and an implementation of the Static Single Assignment form (SSA) representation for Go programs.

Download/Install

The easiest way to install is to run go get -u golang.org/x/tools/.... You can also manually git clone the repository to $GOPATH/src/golang.org/x/tools.

JS/CSS Formatting

This repository uses prettier to format JS and CSS files.

The version of prettier used is 1.18.2.

It is encouraged that all JS and CSS code be run through this before submitting a change. However, it is not a strict requirement enforced by CI.

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see https://golang.org/doc/contribute.html.

The main issue tracker for the tools repository is located at https://github.com/golang/go/issues. Prefix your issue with “x/tools/(your subdir):” in the subject line, so it is easy to find.