go/callgraph/rta: skip generic methods in addRuntimeType

addRuntimeType adds every exported method of a newly discovered concrete
type to the worklist. Program.MethodValue returns nil when the
selection's type is parameterized, which is the case for a generic
method that mentions its own type parameter in its signature, so the nil
reached the worklist and visitFunc dereferenced it. Skip those methods,
as fingerprint already does: reflection cannot call a generic method
without instantiating it first.

Go 1.27 made math/rand/v2.(*Rand).N generic, so this crashed cmd/deadcode
and cmd/callgraph -algo=rta on any program that boxes a *rand.Rand.

The genericmethod test did not catch this because its method is
Foo[T any](): with no type parameter in the signature, MethodValue
returns the uninstantiated function rather than nil. Give it a signature
that uses T, and box the receiver so that addRuntimeType runs at all.

Fixes golang/go#80973

Change-Id: I1b5806285b819bb5b0b02b532754317f6da54d33
Reviewed-on: https://go-review.googlesource.com/c/tools/+/818580
Reviewed-by: Alan Donovan <adonovan@google.com>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
Reviewed-by: David Chase <drchase@google.com>
2 files changed
tree: 25689e0954d7195f89f0f6d26b03a7c11f4dd9ef
  1. benchmark/
  2. blog/
  3. cmd/
  4. container/
  5. copyright/
  6. cover/
  7. go/
  8. gopls/
  9. imports/
  10. internal/
  11. playground/
  12. present/
  13. refactor/
  14. txtar/
  15. .gitattributes
  16. .gitignore
  17. .prettierrc
  18. codereview.cfg
  19. CONTRIBUTING.md
  20. go.mod
  21. go.sum
  22. LICENSE
  23. PATENTS
  24. README.md
README.md

Go Tools

PkgGoDev

This repository provides the golang.org/x/tools module, comprising various tools and packages mostly for static analysis of Go programs, some of which are listed below. Use the “Go reference” link above for more information about any package.

It also contains the golang.org/x/tools/gopls module, whose root package is a language-server protocol (LSP) server for Go. An LSP server analyses the source code of a project and responds to requests from a wide range of editors such as VSCode and Vim, allowing them to support IDE-like functionality.

Selected commands:

  • cmd/goimports formats a Go program like go fmt and additionally inserts import statements for any packages required by the file after it is edited.
  • cmd/callgraph prints the call graph of a Go program.
  • cmd/digraph is a utility for manipulating directed graphs in textual notation.
  • cmd/stringer generates declarations (including a String method) for “enum” types.
  • cmd/toolstash is a utility to simplify working with multiple versions of the Go toolchain.

These commands may be fetched with a command such as

go install golang.org/x/tools/cmd/goimports@latest

Selected packages:

  • go/ssa provides a static single-assignment form (SSA) intermediate representation (IR) for Go programs, similar to a typical compiler, for use by analysis tools.

  • go/packages provides a simple interface for loading, parsing, and type checking a complete Go program from source code.

  • go/analysis provides a framework for modular static analysis of Go programs.

  • go/callgraph provides call graphs of Go programs using a variety of algorithms with different trade-offs.

  • go/ast/inspector provides an optimized means of traversing a Go parse tree for use in analysis tools.

  • go/cfg provides a simple control-flow graph (CFG) for a Go function.

  • go/gcexportdata and go/gccgoexportdata read and write the binary files containing type information used by the standard and gccgo compilers.

  • go/types/objectpath provides a stable naming scheme for named entities (“objects”) in the go/types API.

Numerous other packages provide more esoteric functionality.

Contributing

This repository uses Gerrit for code changes. To learn how to submit changes, see https://go.dev/doc/contribute.

The git repository is https://go.googlesource.com/tools.

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

JavaScript and 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.