mirror of
https://github.com/golang/go.git
synced 2025-10-31 00:30:57 +00:00
4ba69a9a17
ppc64{,le} processor level selection allows the compiler to generate instructions
targeting newer processors and processor-specific optimizations without breaking
compatibility with our current baseline. This feature introduces a new environment
variable, GOPPC64.
GOPPC64 is a GOARCH=ppc64{,le} specific option, for a choice between different
processor levels (i.e. Instruction Set Architecture versions) for which the
compiler will target. The default is 'power8'.
Change-Id: Ic152e283ae1c47084ece4346fa002a3eabb3bb9e
Reviewed-on: https://go-review.googlesource.com/c/go/+/163758
Run-TryBot: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
669 lines
19 KiB
HTML
669 lines
19 KiB
HTML
<!--{
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"Title": "Installing Go from source",
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"Path": "/doc/install/source"
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}-->
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<h2 id="introduction">Introduction</h2>
|
|
|
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<p>
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Go is an open source project, distributed under a
|
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<a href="/LICENSE">BSD-style license</a>.
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This document explains how to check out the sources,
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build them on your own machine, and run them.
|
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</p>
|
|
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<p>
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Most users don't need to do this, and will instead install
|
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from precompiled binary packages as described in
|
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<a href="/doc/install">Getting Started</a>,
|
|
a much simpler process.
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If you want to help develop what goes into those precompiled
|
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packages, though, read on.
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</p>
|
|
|
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<div class="detail">
|
|
|
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<p>
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There are two official Go compiler toolchains.
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|
This document focuses on the <code>gc</code> Go
|
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compiler and tools.
|
|
For information on how to work on <code>gccgo</code>, a more traditional
|
|
compiler using the GCC back end, see
|
|
<a href="/doc/install/gccgo">Setting up and using gccgo</a>.
|
|
</p>
|
|
|
|
<p>
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The Go compilers support eight instruction sets.
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|
There are important differences in the quality of the compilers for the different
|
|
architectures.
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|
</p>
|
|
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|
<dl>
|
|
<dt>
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|
<code>amd64</code> (also known as <code>x86-64</code>)
|
|
</dt>
|
|
<dd>
|
|
A mature implementation.
|
|
</dd>
|
|
<dt>
|
|
<code>386</code> (<code>x86</code> or <code>x86-32</code>)
|
|
</dt>
|
|
<dd>
|
|
Comparable to the <code>amd64</code> port.
|
|
</dd>
|
|
<dt>
|
|
<code>arm</code> (<code>ARM</code>)
|
|
</dt>
|
|
<dd>
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|
Supports Linux, FreeBSD, NetBSD, OpenBSD and Darwin binaries. Less widely used than the other ports.
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</dd>
|
|
<dt>
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<code>arm64</code> (<code>AArch64</code>)
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</dt>
|
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<dd>
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Supports Linux and Darwin binaries. New in 1.5 and not as well exercised as other ports.
|
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</dd>
|
|
<dt>
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|
<code>ppc64, ppc64le</code> (64-bit PowerPC big- and little-endian)
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</dt>
|
|
<dd>
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Supports Linux binaries. New in 1.5 and not as well exercised as other ports.
|
|
</dd>
|
|
<dt>
|
|
<code>mips, mipsle</code> (32-bit MIPS big- and little-endian)
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|
</dt>
|
|
<dd>
|
|
Supports Linux binaries. New in 1.8 and not as well exercised as other ports.
|
|
</dd>
|
|
<dt>
|
|
<code>mips64, mips64le</code> (64-bit MIPS big- and little-endian)
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</dt>
|
|
<dd>
|
|
Supports Linux binaries. New in 1.6 and not as well exercised as other ports.
|
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</dd>
|
|
<dt>
|
|
<code>s390x</code> (IBM System z)
|
|
</dt>
|
|
<dd>
|
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Supports Linux binaries. New in 1.7 and not as well exercised as other ports.
|
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</dd>
|
|
</dl>
|
|
|
|
<p>
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|
Except for things like low-level operating system interface code, the run-time
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|
support is the same in all ports and includes a mark-and-sweep garbage
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collector, efficient array and string slicing, and support for efficient
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goroutines, such as stacks that grow and shrink on demand.
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</p>
|
|
|
|
<p>
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The compilers can target the DragonFly BSD, FreeBSD, Linux, NetBSD, OpenBSD,
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macOS (Darwin), Plan 9, Solaris and Windows operating systems.
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The full set of supported combinations is listed in the discussion of
|
|
<a href="#environment">environment variables</a> below.
|
|
</p>
|
|
|
|
<p>
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|
See the main installation page for the <a href="/doc/install#requirements">overall system requirements</a>.
|
|
The following additional constraints apply to systems that can be built only from source:
|
|
</p>
|
|
|
|
<ul>
|
|
<li>For Linux on PowerPC 64-bit, the minimum supported kernel version is 2.6.37, meaning that
|
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Go does not support CentOS 6 on these systems.
|
|
</li>
|
|
</ul>
|
|
|
|
</div>
|
|
|
|
<h2 id="go14">Install Go compiler binaries</h2>
|
|
|
|
<p>
|
|
The Go toolchain is written in Go. To build it, you need a Go compiler installed.
|
|
The scripts that do the initial build of the tools look for an existing Go tool
|
|
chain in <code>$GOROOT_BOOTSTRAP</code>.
|
|
If unset, the default value of <code>GOROOT_BOOTSTRAP</code>
|
|
is <code>$HOME/go1.4</code>.
|
|
</p>
|
|
|
|
<p>
|
|
There are many options for the bootstrap toolchain.
|
|
After obtaining one, set <code>GOROOT_BOOTSTRAP</code> to the
|
|
directory containing the unpacked tree.
|
|
For example, <code>$GOROOT_BOOTSTRAP/bin/go</code> should be
|
|
the <code>go</code> command binary for the bootstrap toolchain.
|
|
</p>
|
|
|
|
<p>
|
|
To use a binary release as a bootstrap toolchain, see
|
|
<a href="/dl/">the downloads page</a> or use any other
|
|
packaged Go distribution.
|
|
</p>
|
|
|
|
<p>
|
|
To build a bootstrap toolchain from source, use
|
|
either the git branch <code>release-branch.go1.4</code> or
|
|
<a href="https://dl.google.com/go/go1.4-bootstrap-20171003.tar.gz">go1.4-bootstrap-20171003.tar.gz</a>,
|
|
which contains the Go 1.4 source code plus accumulated fixes
|
|
to keep the tools running on newer operating systems.
|
|
(Go 1.4 was the last distribution in which the toolchain was written in C.)
|
|
After unpacking the Go 1.4 source, <code>cd</code> to
|
|
the <code>src</code> subdirectory, set <code>CGO_ENABLED=0</code> in
|
|
the environment, and run <code>make.bash</code> (or,
|
|
on Windows, <code>make.bat</code>).
|
|
</p>
|
|
|
|
<p>
|
|
To cross-compile a bootstrap toolchain from source, which is
|
|
necessary on systems Go 1.4 did not target (for
|
|
example, <code>linux/ppc64le</code>), install Go on a different system
|
|
and run <a href="/src/bootstrap.bash">bootstrap.bash</a>.
|
|
</p>
|
|
|
|
<p>
|
|
When run as (for example)
|
|
</p>
|
|
|
|
<pre>
|
|
$ GOOS=linux GOARCH=ppc64 ./bootstrap.bash
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|
</pre>
|
|
|
|
<p>
|
|
<code>bootstrap.bash</code> cross-compiles a toolchain for that <code>GOOS/GOARCH</code>
|
|
combination, leaving the resulting tree in <code>../../go-${GOOS}-${GOARCH}-bootstrap</code>.
|
|
That tree can be copied to a machine of the given target type
|
|
and used as <code>GOROOT_BOOTSTRAP</code> to bootstrap a local build.
|
|
</p>
|
|
|
|
<p>
|
|
To use gccgo as the bootstrap toolchain, you need to arrange
|
|
for <code>$GOROOT_BOOTSTRAP/bin/go</code> to be the go tool that comes
|
|
as part of gccgo 5. For example on Ubuntu Vivid:
|
|
</p>
|
|
|
|
<pre>
|
|
$ sudo apt-get install gccgo-5
|
|
$ sudo update-alternatives --set go /usr/bin/go-5
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|
$ GOROOT_BOOTSTRAP=/usr ./make.bash
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</pre>
|
|
|
|
<h2 id="git">Install Git, if needed</h2>
|
|
|
|
<p>
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|
To perform the next step you must have Git installed. (Check that you
|
|
have a <code>git</code> command before proceeding.)
|
|
</p>
|
|
|
|
<p>
|
|
If you do not have a working Git installation,
|
|
follow the instructions on the
|
|
<a href="https://git-scm.com/downloads">Git downloads</a> page.
|
|
</p>
|
|
|
|
<h2 id="ccompiler">(Optional) Install a C compiler</h2>
|
|
|
|
<p>
|
|
To build a Go installation
|
|
with <code><a href="/cmd/cgo">cgo</a></code> support, which permits Go
|
|
programs to import C libraries, a C compiler such as <code>gcc</code>
|
|
or <code>clang</code> must be installed first. Do this using whatever
|
|
installation method is standard on the system.
|
|
</p>
|
|
|
|
<p>
|
|
To build without <code>cgo</code>, set the environment variable
|
|
<code>CGO_ENABLED=0</code> before running <code>all.bash</code> or
|
|
<code>make.bash</code>.
|
|
</p>
|
|
|
|
<h2 id="fetch">Fetch the repository</h2>
|
|
|
|
<p>Go will install to a directory named <code>go</code>.
|
|
Change to the directory that will be its parent
|
|
and make sure the <code>go</code> directory does not exist.
|
|
Then clone the repository and check out the latest release tag
|
|
(<code class="versionTag">go1.9</code>, for example):</p>
|
|
|
|
<pre>
|
|
$ git clone https://go.googlesource.com/go
|
|
$ cd go
|
|
$ git checkout <span class="versionTag"><i><tag></i></span>
|
|
</pre>
|
|
|
|
<p class="whereTag">
|
|
Where <code><tag></code> is the version string of the release.
|
|
</p>
|
|
|
|
<h2 id="head">(Optional) Switch to the master branch</h2>
|
|
|
|
<p>If you intend to modify the go source code, and
|
|
<a href="/doc/contribute.html">contribute your changes</a>
|
|
to the project, then move your repository
|
|
off the release branch, and onto the master (development) branch.
|
|
Otherwise, skip this step.</p>
|
|
|
|
<pre>
|
|
$ git checkout master
|
|
</pre>
|
|
|
|
<h2 id="install">Install Go</h2>
|
|
|
|
<p>
|
|
To build the Go distribution, run
|
|
</p>
|
|
|
|
<pre>
|
|
$ cd src
|
|
$ ./all.bash
|
|
</pre>
|
|
|
|
<p>
|
|
(To build under Windows use <code>all.bat</code>.)
|
|
</p>
|
|
|
|
<p>
|
|
If all goes well, it will finish by printing output like:
|
|
</p>
|
|
|
|
<pre>
|
|
ALL TESTS PASSED
|
|
|
|
---
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|
Installed Go for linux/amd64 in /home/you/go.
|
|
Installed commands in /home/you/go/bin.
|
|
*** You need to add /home/you/go/bin to your $PATH. ***
|
|
</pre>
|
|
|
|
<p>
|
|
where the details on the last few lines reflect the operating system,
|
|
architecture, and root directory used during the install.
|
|
</p>
|
|
|
|
<div class="detail">
|
|
<p>
|
|
For more information about ways to control the build, see the discussion of
|
|
<a href="#environment">environment variables</a> below.
|
|
<code>all.bash</code> (or <code>all.bat</code>) runs important tests for Go,
|
|
which can take more time than simply building Go. If you do not want to run
|
|
the test suite use <code>make.bash</code> (or <code>make.bat</code>)
|
|
instead.
|
|
</p>
|
|
</div>
|
|
|
|
|
|
<h2 id="testing">Testing your installation</h2>
|
|
|
|
<p>
|
|
Check that Go is installed correctly by building a simple program.
|
|
</p>
|
|
|
|
<p>
|
|
Create a file named <code>hello.go</code> and put the following program in it:
|
|
</p>
|
|
|
|
<pre>
|
|
package main
|
|
|
|
import "fmt"
|
|
|
|
func main() {
|
|
fmt.Printf("hello, world\n")
|
|
}
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|
</pre>
|
|
|
|
<p>
|
|
Then run it with the <code>go</code> tool:
|
|
</p>
|
|
|
|
<pre>
|
|
$ go run hello.go
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hello, world
|
|
</pre>
|
|
|
|
<p>
|
|
If you see the "hello, world" message then Go is installed correctly.
|
|
</p>
|
|
|
|
<h2 id="gopath">Set up your work environment</h2>
|
|
|
|
<p>
|
|
You're almost done.
|
|
You just need to do a little more setup.
|
|
</p>
|
|
|
|
<p>
|
|
<a href="/doc/code.html" class="download" id="start">
|
|
<span class="big">How to Write Go Code</span>
|
|
<span class="desc">Learn how to set up and use the Go tools</span>
|
|
</a>
|
|
</p>
|
|
|
|
<p>
|
|
The <a href="/doc/code.html">How to Write Go Code</a> document
|
|
provides <b>essential setup instructions</b> for using the Go tools.
|
|
</p>
|
|
|
|
|
|
<h2 id="tools">Install additional tools</h2>
|
|
|
|
<p>
|
|
The source code for several Go tools (including <a href="/cmd/godoc/">godoc</a>)
|
|
is kept in <a href="https://golang.org/x/tools">the go.tools repository</a>.
|
|
To install one of the tools (<code>godoc</code> in this case):
|
|
</p>
|
|
|
|
<pre>
|
|
$ go get golang.org/x/tools/cmd/godoc
|
|
</pre>
|
|
|
|
<p>
|
|
To install these tools, the <code>go</code> <code>get</code> command requires
|
|
that <a href="#git">Git</a> be installed locally.
|
|
</p>
|
|
|
|
<p>
|
|
You must also have a workspace (<code>GOPATH</code>) set up;
|
|
see <a href="/doc/code.html">How to Write Go Code</a> for the details.
|
|
</p>
|
|
|
|
<h2 id="community">Community resources</h2>
|
|
|
|
<p>
|
|
The usual community resources such as
|
|
<code>#go-nuts</code> on the <a href="https://freenode.net/">Freenode</a> IRC server
|
|
and the
|
|
<a href="//groups.google.com/group/golang-nuts">Go Nuts</a>
|
|
mailing list have active developers that can help you with problems
|
|
with your installation or your development work.
|
|
For those who wish to keep up to date,
|
|
there is another mailing list, <a href="//groups.google.com/group/golang-checkins">golang-checkins</a>,
|
|
that receives a message summarizing each checkin to the Go repository.
|
|
</p>
|
|
|
|
<p>
|
|
Bugs can be reported using the <a href="//golang.org/issue/new">Go issue tracker</a>.
|
|
</p>
|
|
|
|
|
|
<h2 id="releases">Keeping up with releases</h2>
|
|
|
|
<p>
|
|
New releases are announced on the
|
|
<a href="//groups.google.com/group/golang-announce">golang-announce</a>
|
|
mailing list.
|
|
Each announcement mentions the latest release tag, for instance,
|
|
<code class="versionTag">go1.9</code>.
|
|
</p>
|
|
|
|
<p>
|
|
To update an existing tree to the latest release, you can run:
|
|
</p>
|
|
|
|
<pre>
|
|
$ cd go/src
|
|
$ git fetch
|
|
$ git checkout <span class="versionTag"><i><tag></i></psan>
|
|
$ ./all.bash
|
|
</pre>
|
|
|
|
<p class="whereTag">
|
|
Where <code><tag></code> is the version string of the release.
|
|
</p>
|
|
|
|
|
|
<h2 id="environment">Optional environment variables</h2>
|
|
|
|
<p>
|
|
The Go compilation environment can be customized by environment variables.
|
|
<i>None is required by the build</i>, but you may wish to set some
|
|
to override the defaults.
|
|
</p>
|
|
|
|
<ul>
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|
<li><code>$GOROOT</code>
|
|
<p>
|
|
The root of the Go tree, often <code>$HOME/go1.X</code>.
|
|
Its value is built into the tree when it is compiled, and
|
|
defaults to the parent of the directory where <code>all.bash</code> was run.
|
|
There is no need to set this unless you want to switch between multiple
|
|
local copies of the repository.
|
|
</p>
|
|
</li>
|
|
|
|
<li><code>$GOROOT_FINAL</code>
|
|
<p>
|
|
The value assumed by installed binaries and scripts when
|
|
<code>$GOROOT</code> is not set explicitly.
|
|
It defaults to the value of <code>$GOROOT</code>.
|
|
If you want to build the Go tree in one location
|
|
but move it elsewhere after the build, set
|
|
<code>$GOROOT_FINAL</code> to the eventual location.
|
|
</p>
|
|
</li>
|
|
|
|
<li><code>$GOOS</code> and <code>$GOARCH</code>
|
|
<p>
|
|
The name of the target operating system and compilation architecture.
|
|
These default to the values of <code>$GOHOSTOS</code> and
|
|
<code>$GOHOSTARCH</code> respectively (described below).
|
|
</li>
|
|
|
|
<p>
|
|
Choices for <code>$GOOS</code> are
|
|
<code>darwin</code> (macOS 10.10 and above and iOS), <code>dragonfly</code>, <code>freebsd</code>,
|
|
<code>linux</code>, <code>netbsd</code>, <code>openbsd</code>,
|
|
<code>plan9</code>, <code>solaris</code> and <code>windows</code>.
|
|
Choices for <code>$GOARCH</code> are
|
|
<code>amd64</code> (64-bit x86, the most mature port),
|
|
<code>386</code> (32-bit x86), <code>arm</code> (32-bit ARM), <code>arm64</code> (64-bit ARM),
|
|
<code>ppc64le</code> (PowerPC 64-bit, little-endian), <code>ppc64</code> (PowerPC 64-bit, big-endian),
|
|
<code>mips64le</code> (MIPS 64-bit, little-endian), <code>mips64</code> (MIPS 64-bit, big-endian),
|
|
<code>mipsle</code> (MIPS 32-bit, little-endian), <code>mips</code> (MIPS 32-bit, big-endian), and
|
|
<code>s390x</code> (IBM System z 64-bit, big-endian).
|
|
The valid combinations of <code>$GOOS</code> and <code>$GOARCH</code> are:
|
|
<table cellpadding="0">
|
|
<tr>
|
|
<th width="50"></th><th align="left" width="100"><code>$GOOS</code></th> <th align="left" width="100"><code>$GOARCH</code></th>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>android</code></td> <td><code>arm</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>darwin</code></td> <td><code>386</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>darwin</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>darwin</code></td> <td><code>arm</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>darwin</code></td> <td><code>arm64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>dragonfly</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>freebsd</code></td> <td><code>386</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>freebsd</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>freebsd</code></td> <td><code>arm</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>386</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>arm</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>arm64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>ppc64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>ppc64le</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>mips</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>mipsle</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>mips64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>mips64le</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>linux</code></td> <td><code>s390x</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>netbsd</code></td> <td><code>386</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>netbsd</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>netbsd</code></td> <td><code>arm</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>openbsd</code></td> <td><code>386</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>openbsd</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>openbsd</code></td> <td><code>arm</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>plan9</code></td> <td><code>386</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>plan9</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>solaris</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>windows</code></td> <td><code>386</code></td>
|
|
</tr>
|
|
<tr>
|
|
<td></td><td><code>windows</code></td> <td><code>amd64</code></td>
|
|
</tr>
|
|
</table>
|
|
<br>
|
|
|
|
<li><code>$GOHOSTOS</code> and <code>$GOHOSTARCH</code>
|
|
<p>
|
|
The name of the host operating system and compilation architecture.
|
|
These default to the local system's operating system and
|
|
architecture.
|
|
</p>
|
|
</li>
|
|
|
|
<p>
|
|
Valid choices are the same as for <code>$GOOS</code> and
|
|
<code>$GOARCH</code>, listed above.
|
|
The specified values must be compatible with the local system.
|
|
For example, you should not set <code>$GOHOSTARCH</code> to
|
|
<code>arm</code> on an x86 system.
|
|
</p>
|
|
|
|
<li><code>$GOBIN</code>
|
|
<p>
|
|
The location where Go binaries will be installed.
|
|
The default is <code>$GOROOT/bin</code>.
|
|
After installing, you will want to arrange to add this
|
|
directory to your <code>$PATH</code>, so you can use the tools.
|
|
If <code>$GOBIN</code> is set, the <a href="/cmd/go">go command</a>
|
|
installs all commands there.
|
|
</p>
|
|
</li>
|
|
|
|
<li><code>$GO386</code> (for <code>386</code> only, default is auto-detected
|
|
if built on either <code>386</code> or <code>amd64</code>, <code>387</code> otherwise)
|
|
<p>
|
|
This controls the code generated by gc to use either the 387 floating-point unit
|
|
(set to <code>387</code>) or SSE2 instructions (set to <code>sse2</code>) for
|
|
floating point computations.
|
|
</p>
|
|
<ul>
|
|
<li><code>GO386=387</code>: use x87 for floating point operations; should support all x86 chips (Pentium MMX or later).</li>
|
|
<li><code>GO386=sse2</code>: use SSE2 for floating point operations; has better performance than 387, but only available on Pentium 4/Opteron/Athlon 64 or later.</li>
|
|
</ul>
|
|
</li>
|
|
|
|
<li><code>$GOARM</code> (for <code>arm</code> only; default is auto-detected if building
|
|
on the target processor, 6 if not)
|
|
<p>
|
|
This sets the ARM floating point co-processor architecture version the run-time
|
|
should target. If you are compiling on the target system, its value will be auto-detected.
|
|
</p>
|
|
<ul>
|
|
<li><code>GOARM=5</code>: use software floating point; when CPU doesn't have VFP co-processor</li>
|
|
<li><code>GOARM=6</code>: use VFPv1 only; default if cross compiling; usually ARM11 or better cores (VFPv2 or better is also supported)</li>
|
|
<li><code>GOARM=7</code>: use VFPv3; usually Cortex-A cores</li>
|
|
</ul>
|
|
<p>
|
|
If in doubt, leave this variable unset, and adjust it if required
|
|
when you first run the Go executable.
|
|
The <a href="//golang.org/wiki/GoArm">GoARM</a> page
|
|
on the <a href="//golang.org/wiki">Go community wiki</a>
|
|
contains further details regarding Go's ARM support.
|
|
</p>
|
|
</li>
|
|
|
|
<li><code>$GOMIPS</code> (for <code>mips</code> and <code>mipsle</code> only) <br> <code>$GOMIPS64</code> (for <code>mips64</code> and <code>mips64le</code> only)
|
|
<p>
|
|
These variables set whether to use floating point instructions. Set to "<code>hardfloat</code>" to use floating point instructions; this is the default. Set to "<code>softfloat</code>" to use soft floating point.
|
|
</p>
|
|
</li>
|
|
|
|
<li><code>$GOPPC64</code> (for <code>ppc64</code> and <code>ppc64le</code> only)
|
|
<p>
|
|
This variable sets the processor level (i.e. Instruction Set Architecture version)
|
|
for which the compiler will target. The default is <code>power8</code>.
|
|
</p>
|
|
<ul>
|
|
<li><code>GOPPC64=power8</code>: generate ISA v2.07 instructions</li>
|
|
<li><code>GOPPC64=power9</code>: generate ISA v3.00 instructions</li>
|
|
</ul>
|
|
</li>
|
|
|
|
</ul>
|
|
|
|
<p>
|
|
Note that <code>$GOARCH</code> and <code>$GOOS</code> identify the
|
|
<em>target</em> environment, not the environment you are running on.
|
|
In effect, you are always cross-compiling.
|
|
By architecture, we mean the kind of binaries
|
|
that the target environment can run:
|
|
an x86-64 system running a 32-bit-only operating system
|
|
must set <code>GOARCH</code> to <code>386</code>,
|
|
not <code>amd64</code>.
|
|
</p>
|
|
|
|
<p>
|
|
If you choose to override the defaults,
|
|
set these variables in your shell profile (<code>$HOME/.bashrc</code>,
|
|
<code>$HOME/.profile</code>, or equivalent). The settings might look
|
|
something like this:
|
|
</p>
|
|
|
|
<pre>
|
|
export GOARCH=amd64
|
|
export GOOS=linux
|
|
</pre>
|
|
|
|
<p>
|
|
although, to reiterate, none of these variables needs to be set to build,
|
|
install, and develop the Go tree.
|
|
</p>
|