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doc/gccgo: update gcc status, remove double spaces

This change updates the status of gccgo 8 and gccgo 9, which are now
released.

It also replaces every instance of two-spaces with one space in text
paragraphs, which is the preferred style in Go documentation.

Fixes #34167

Change-Id: I94a4d85c06281f2623d39a68db7b6c95b5867999
Reviewed-on: https://go-review.googlesource.com/c/go/+/193842
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit is contained in:
Alberto Donizetti 2019-09-07 16:31:36 +02:00
parent 9cce08d724
commit 77aea69176

View File

@ -5,8 +5,8 @@
<p>
This document explains how to use gccgo, a compiler for
the Go language. The gccgo compiler is a new frontend
for GCC, the widely used GNU compiler. Although the
the Go language. The gccgo compiler is a new frontend
for GCC, the widely used GNU compiler. Although the
frontend itself is under a BSD-style license, gccgo is
normally used as part of GCC and is then covered by
the <a href="https://www.gnu.org/licenses/gpl.html">GNU General Public
@ -24,10 +24,10 @@ compiler.
<p>
The simplest way to install gccgo is to install a GCC binary release
built to include Go support. GCC binary releases are available from
built to include Go support. GCC binary releases are available from
<a href="https://gcc.gnu.org/install/binaries.html">various
websites</a> and are typically included as part of GNU/Linux
distributions. We expect that most people who build these binaries
distributions. We expect that most people who build these binaries
will include Go support.
</p>
@ -38,7 +38,7 @@ The GCC 4.7.1 release and all later 4.7 releases include a complete
<p>
Due to timing, the GCC 4.8.0 and 4.8.1 releases are close to but not
identical to Go 1.1. The GCC 4.8.2 release includes a complete Go
identical to Go 1.1. The GCC 4.8.2 release includes a complete Go
1.1.2 implementation.
</p>
@ -48,28 +48,32 @@ The GCC 4.9 releases include a complete Go 1.2 implementation.
<p>
The GCC 5 releases include a complete implementation of the Go 1.4
user libraries. The Go 1.4 runtime is not fully merged, but that
user libraries. The Go 1.4 runtime is not fully merged, but that
should not be visible to Go programs.
</p>
<p>
The GCC 6 releases include a complete implementation of the Go 1.6.1
user libraries. The Go 1.6 runtime is not fully merged, but that
user libraries. The Go 1.6 runtime is not fully merged, but that
should not be visible to Go programs.
</p>
<p>
The GCC 7 releases include a complete implementation of the Go 1.8.1
user libraries. As with earlier releases, the Go 1.8 runtime is not
user libraries. As with earlier releases, the Go 1.8 runtime is not
fully merged, but that should not be visible to Go programs.
</p>
<p>
The GCC 8 releases are expected to include a complete implementation
of the Go 1.10 release, depending on release timing. The Go 1.10
runtime has now been fully merged into the GCC development sources,
and concurrent garbage collection is expected to be fully supported in
GCC 8.
The GCC 8 releases include a complete implementation of the Go 1.10.1
release. The Go 1.10 runtime has now been fully merged into the GCC
development sources, and concurrent garbage collection is fully
supported.
</p>
<p>
The GCC 9 releases include a complete implementation of the Go 1.12.2
release.
</p>
<h2 id="Source_code">Source code</h2>
@ -77,10 +81,10 @@ GCC 8.
<p>
If you cannot use a release, or prefer to build gccgo for
yourself,
the gccgo source code is accessible via Subversion. The
the gccgo source code is accessible via Subversion. The
GCC web site
has <a href="https://gcc.gnu.org/svn.html">instructions for getting the
GCC source code</a>. The gccgo source code is included. As a
GCC source code</a>. The gccgo source code is included. As a
convenience, a stable version of the Go support is available in
a branch of the main GCC code
repository: <code>svn://gcc.gnu.org/svn/gcc/branches/gccgo</code>.
@ -90,7 +94,7 @@ This branch is periodically updated with stable Go compiler sources.
<p>
Note that although <code>gcc.gnu.org</code> is the most convenient way
to get the source code for the Go frontend, it is not where the master
sources live. If you want to contribute changes to the Go frontend
sources live. If you want to contribute changes to the Go frontend
compiler, see <a href="/doc/gccgo_contribute.html">Contributing to
gccgo</a>.
</p>
@ -100,16 +104,16 @@ gccgo</a>.
<p>
Building gccgo is just like building GCC
with one or two additional options. See
with one or two additional options. See
the <a href="https://gcc.gnu.org/install/">instructions on the gcc web
site</a>. When you run <code>configure</code>, add the
site</a>. When you run <code>configure</code>, add the
option <code>--enable-languages=c,c++,go</code> (along with other
languages you may want to build). If you are targeting a 32-bit x86,
languages you may want to build). If you are targeting a 32-bit x86,
then you will want to build gccgo to default to
supporting locked compare and exchange instructions; do this by also
using the <code>configure</code> option <code>--with-arch=i586</code>
(or a newer architecture, depending on where you need your programs to
run). If you are targeting a 64-bit x86, but sometimes want to use
run). If you are targeting a 64-bit x86, but sometimes want to use
the <code>-m32</code> option, then use the <code>configure</code>
option <code>--with-arch-32=i586</code>.
</p>
@ -118,18 +122,18 @@ option <code>--with-arch-32=i586</code>.
<p>
On x86 GNU/Linux systems the gccgo compiler is able to
use a small discontiguous stack for goroutines. This permits programs
use a small discontiguous stack for goroutines. This permits programs
to run many more goroutines, since each goroutine can use a relatively
small stack. Doing this requires using the gold linker version 2.22
or later. You can either install GNU binutils 2.22 or later, or you
small stack. Doing this requires using the gold linker version 2.22
or later. You can either install GNU binutils 2.22 or later, or you
can build gold yourself.
</p>
<p>
To build gold yourself, build the GNU binutils,
using <code>--enable-gold=default</code> when you run
the <code>configure</code> script. Before building, you must install
the flex and bison packages. A typical sequence would look like
the <code>configure</code> script. Before building, you must install
the flex and bison packages. A typical sequence would look like
this (you can replace <code>/opt/gold</code> with any directory to
which you have write access):
</p>
@ -157,7 +161,7 @@ option <code>--with-ld=<var>GOLD_BINARY</var></code>.
A number of prerequisites are required to build GCC, as
described on
the <a href="https://gcc.gnu.org/install/prerequisites.html">gcc web
site</a>. It is important to install all the prerequisites before
site</a>. It is important to install all the prerequisites before
running the gcc <code>configure</code> script.
The prerequisite libraries can be conveniently downloaded using the
script <code>contrib/download_prerequisites</code> in the GCC sources.
@ -183,7 +187,7 @@ make install
<h2 id="Using_gccgo">Using gccgo</h2>
<p>
The gccgo compiler works like other gcc frontends. As of GCC 5 the gccgo
The gccgo compiler works like other gcc frontends. As of GCC 5 the gccgo
installation also includes a version of the <code>go</code> command,
which may be used to build Go programs as described at
<a href="https://golang.org/cmd/go">https://golang.org/cmd/go</a>.
@ -208,7 +212,7 @@ gccgo -o file file.o
<p>
To run the resulting file, you will need to tell the program where to
find the compiled Go packages. There are a few ways to do this:
find the compiled Go packages. There are a few ways to do this:
</p>
<ul>
@ -226,11 +230,11 @@ export LD_LIBRARY_PATH
<p>
Here <code>${prefix}</code> is the <code>--prefix</code> option used
when building gccgo. For a binary install this is
normally <code>/usr</code>. Whether to use <code>lib</code>
when building gccgo. For a binary install this is
normally <code>/usr</code>. Whether to use <code>lib</code>
or <code>lib64</code> depends on the target.
Typically <code>lib64</code> is correct for x86_64 systems,
and <code>lib</code> is correct for other systems. The idea is to
and <code>lib</code> is correct for other systems. The idea is to
name the directory where <code>libgo.so</code> is found.
</p>
@ -325,9 +329,9 @@ objcopy -j .go_export FILE.o FILE.gox
<p>
The gccgo compiler will look in the current
directory for import files. In more complex scenarios you
directory for import files. In more complex scenarios you
may pass the <code>-I</code> or <code>-L</code> option to
gccgo. Both options take directories to search. The
gccgo. Both options take directories to search. The
<code>-L</code> option is also passed to the linker.
</p>
@ -348,11 +352,11 @@ gccgo -o main main.o mypackage.o # Explicitly links with mypackage.o
<p>
If you use the <code>-g</code> option when you compile, you can run
<code>gdb</code> on your executable. The debugger has only limited
knowledge about Go. You can set breakpoints, single-step,
etc. You can print variables, but they will be printed as though they
had C/C++ types. For numeric types this doesn't matter. Go strings
and interfaces will show up as two-element structures. Go
<code>gdb</code> on your executable. The debugger has only limited
knowledge about Go. You can set breakpoints, single-step,
etc. You can print variables, but they will be printed as though they
had C/C++ types. For numeric types this doesn't matter. Go strings
and interfaces will show up as two-element structures. Go
maps and channels are always represented as C pointers to run-time
structures.
</p>
@ -399,7 +403,7 @@ assuming that the C pointer does point to 10 elements.
</p>
<p>
A slice in Go is a structure. The current definition is
A slice in Go is a structure. The current definition is
(this is <b style="color: red;">subject to change</b>):
</p>
@ -413,15 +417,15 @@ struct __go_slice {
<p>
The type of a Go function is a pointer to a struct (this is
<b style="color: red;">subject to change</b>). The first field in the
<b style="color: red;">subject to change</b>). The first field in the
struct points to the code of the function, which will be equivalent to
a pointer to a C function whose parameter types are equivalent, with
an additional trailing parameter. The trailing parameter is the
an additional trailing parameter. The trailing parameter is the
closure, and the argument to pass is a pointer to the Go function
struct.
When a Go function returns more than one value, the C function returns
a struct. For example, these functions are roughly equivalent:
a struct. For example, these functions are roughly equivalent:
</p>
<pre>
@ -458,7 +462,7 @@ pointer while the C function is still using it.
<p>
Go code can call C functions directly using a Go extension implemented
in gccgo: a function declaration may be preceded by
<code>//extern NAME</code>. For example, here is how the C function
<code>//extern NAME</code>. For example, here is how the C function
<code>open</code> can be declared in Go:
</p>
@ -518,11 +522,11 @@ the <code>-gccgo</code> option instead.
<p>
Compile your C code as usual, and add the option
<code>-fdump-go-spec=<var>FILENAME</var></code>. This will create the
<code>-fdump-go-spec=<var>FILENAME</var></code>. This will create the
file <code><var>FILENAME</var></code> as a side effect of the
compilation. This file will contain Go declarations for the types,
variables and functions declared in the C code. C types that can not
be represented in Go will be recorded as comments in the Go code. The
compilation. This file will contain Go declarations for the types,
variables and functions declared in the C code. C types that can not
be represented in Go will be recorded as comments in the Go code. The
generated file will not have a <code>package</code> declaration, but
can otherwise be compiled directly by gccgo.
</p>