77a2113925
Consider an interface value i of type I and concrete value c of type C. Prior to this CL, i==c was evaluated as I(c) == i Evaluating I(c) can allocate. This CL changes the evaluation of i==c to x, ok := i.(C); ok && x == c The new generated code is shorter and does not allocate directly. If C is small, as it is in every instance in the stdlib, the new code also uses less stack space and makes one runtime call instead of two. If C is very large, the original implementation is used. The cutoff for "very large" is 1<<16, following the stack vs heap cutoff used elsewhere. This kind of comparison occurs in 38 places in the stdlib, mostly in the net and os packages. benchmark old ns/op new ns/op delta BenchmarkEqEfaceConcrete 29.5 7.92 -73.15% BenchmarkEqIfaceConcrete 32.1 7.90 -75.39% BenchmarkNeEfaceConcrete 29.9 7.90 -73.58% BenchmarkNeIfaceConcrete 35.9 7.90 -77.99% Fixes #9370. Change-Id: I7c4555950bcd6406ee5c613be1f2128da2c9a2b7 Reviewed-on: https://go-review.googlesource.com/2096 Reviewed-by: Russ Cox <rsc@golang.org> Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com> |
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README.md
The Go Programming Language
Go is an open source programming language that makes it easy to build simple, reliable, and efficient software.
For documentation about how to install and use Go, visit https://golang.org/ or load doc/install-source.html in your web browser.
Our canonical Git repository is located at https://go.googlesource.com/go. (There is a mirror of the repository at https://github.com/golang/go.)
Please report issues here: https://golang.org/issue/new
Go is the work of hundreds of contributors. We appreciate your help!
To contribute, please read the contribution guidelines: https://golang.org/doc/contribute.html
Please note that we do not use pull requests.
Unless otherwise noted, the Go source files are distributed under the BSD-style license found in the LICENSE file.
--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.