gopls/internal/analysis/yield: handle booleans better

This change improves the analysis of control flow conditions,
especially in the presence of conditions materialized
as booleans.

Previously, we would peephole-optimize conditions
of the form phi(false, ..., yield), but not cases such as
phi(false, phi(false, ..., yield), yield). Now we apply
the optimization to all leaves of the phi graph.

Happily, the only test failure encountered while making
this change was the one that intentionally recorded the
limitation of the old algorithm. Sadly, it took me a while
to notice that this failure was a good thing and stop
futzing with my logic!

+ tests

Fixes golang/go#74136
Fixes golang/go#75924

Change-Id: I474d303a728400c37a8dfbbdf1b5172372137d1c
Reviewed-on: https://go-review.googlesource.com/c/tools/+/712401
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Markus Kusano <kusano@google.com>
2 files changed
tree: db409a84f7144ee5a266bff14f03d75d35f1919c
  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.