mirror of
https://github.com/golang/go
synced 2024-11-23 04:40:09 -07:00
doc/go1.4.html: much of the go command's changes
still need to do internal and import comments LGTM=adg R=golang-codereviews, adg CC=golang-codereviews https://golang.org/cl/160600043
This commit is contained in:
Rob Pike
parent
d39907e649
commit
cd69218bdf
178
doc/go1.4.html
178
doc/go1.4.html
@ -87,7 +87,35 @@ may now be <code>nil</code>.
|
||||
TODO news about foobarblatz
|
||||
</p>
|
||||
|
||||
<h2 id="runtime">Changes to the runtime</h2>
|
||||
<h2 id="compatibility">Changes to the compatibility guidelines</h2>
|
||||
|
||||
<p>
|
||||
The <a href="/pkg/unsafe/"><code>unsafe</code></a> package allows one
|
||||
to defeat Go's type system by exploiting internal details of the implementation
|
||||
or machine representation of data.
|
||||
It was never explicitly specified what use of <code>unsafe</code> meant
|
||||
with respect to compatibility as specified in the
|
||||
<a href="go1compat.html">Go compatibilty guidelines</a>.
|
||||
The answer, of course, is that we can make no promise of compatibility
|
||||
for code that does unsafe things.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
We have clarified this situation in the documentation included in the release.
|
||||
The <a href="go1compat.html">Go compatibilty guidelines</a> and the
|
||||
docs for the <a href="/pkg/unsafe/"><code>unsafe</code></a> package
|
||||
are now explicit that unsafe code is not guaranteed to remain compatible.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
<em>Updating</em>: Nothing technical has changed; this is just a clarification
|
||||
of the documentation.
|
||||
</p>
|
||||
|
||||
|
||||
<h2 id="impl">Changes to the implementations and tools</h2>
|
||||
|
||||
<h3 id="runtime">Changes to the runtime</h3>
|
||||
|
||||
<p>
|
||||
Up to Go 1.4, the runtime (garbage collector, concurrency support, interface management,
|
||||
@ -140,58 +168,114 @@ so the effect is minimal, but programs that store integers (for example) in
|
||||
interfaces will see more allocations.
|
||||
</p>
|
||||
|
||||
<h2 id="compatibility">Changes to the compatibility guidelines</h2>
|
||||
|
||||
<p>
|
||||
The <a href="/pkg/unsafe/"><code>unsafe</code></a> package allows one
|
||||
to defeat Go's type system by exploiting internal details of the implementation
|
||||
or machine representation of data.
|
||||
It was never explicitly specified what use of <code>unsafe</code> meant
|
||||
with respect to compatibility as specified in the
|
||||
<a href="go1compat.html">Go compatibilty guidelines</a>.
|
||||
The answer, of course, is that we can make no promise of compatibility
|
||||
for code that does unsafe things.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
We have clarified this situation in the documentation included in the release.
|
||||
The <a href="go1compat.html">Go compatibilty guidelines</a> and the
|
||||
docs for the <a href="/pkg/unsafe/"><code>unsafe</code></a> package
|
||||
are now explicit that unsafe code is not guaranteed to remain compatible.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
<em>Updating</em>: Nothing technical has changed; this is just a clarification
|
||||
of the documentation.
|
||||
</p>
|
||||
|
||||
|
||||
<h2 id="impl">Changes to the implementations and tools</h2>
|
||||
|
||||
<h3 id="garbage_collector">Changes to the garbage collector</h3>
|
||||
|
||||
<p>
|
||||
TODO news about garbage collection
|
||||
</p>
|
||||
|
||||
<h3 id="stacks">Stack</h3>
|
||||
|
||||
<p>
|
||||
TODO news about stacks
|
||||
</p>
|
||||
|
||||
<h3 id="gccgo">Status of gccgo</h3>
|
||||
|
||||
<p>
|
||||
TODO gccgo news
|
||||
</p>
|
||||
|
||||
<h3 id="gocmd">Changes to the go command</h3>
|
||||
<h3 id="internalpackages">Internal packages</h3>
|
||||
<pre>
|
||||
TODO prose for these
|
||||
cmd/go: implement "internal" (CL 120600043)
|
||||
</pre>
|
||||
|
||||
<h3 id="importcomments">Import comments</h3>
|
||||
|
||||
<pre>
|
||||
TODO prose for these
|
||||
cmd/go: import comments (CL 124940043)
|
||||
</pre>
|
||||
|
||||
<h3 id="gogenerate">The go generate subcommand</h3>
|
||||
|
||||
<p>
|
||||
TODO go command news
|
||||
The <a href="/cmd/go/"><code>go</code></a> command has a new subcommand,
|
||||
<a href="/cmd/go/#hdr-Generate_Go_files_by_processing_source"><code>go generate</code></a>,
|
||||
to automate the running of tools to generate source code before compilation.
|
||||
For example, it can be used to run the <a href="http://en.wikipedia.org/wiki/Yacc"><code>yacc</code></a>
|
||||
compiler-compiler on a <code>.y</code> file to produce the Go source file implementing the grammar,
|
||||
or to automate the generation of <code>String</code> methods for typed constants using the new
|
||||
<a href="http://godoc.org/code.google.com/p/go.tools/cmd/stringer">stringer</a>
|
||||
tool in the <code>go.tools</code> repository.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
For more information, see the
|
||||
<a href="http://golang.org/s/go1.4-generate">design document</a>.
|
||||
</p>
|
||||
|
||||
<h3 id="filenames">Change to file name handling</h3>
|
||||
|
||||
<p>
|
||||
Build constraints, also known as build tags, control compilation by including or excluding files
|
||||
(see the documentation <a href="/pkg/go/build/"><code>/go/build</code></a>).
|
||||
Compilation can also be controlled by the name of the file itself by "tagging" the file with
|
||||
a suffix (before the <code>.go</code> or <code>.s</code> extension) with an underscore
|
||||
and the name of the architecture or operating system.
|
||||
For instance, the file <code>gopher_arm.go</code> will only be compiled if the target
|
||||
processor is an ARM.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
Before Go 1.4, a file called just <code>arm.go</code> was similarly tagged, but this behavior
|
||||
can break sources when new architectures are added, causing files to suddenly become tagged.
|
||||
In 1.4, therefore, a file will be tagged in this manner only if the tag (architecture or operating
|
||||
system name) is preceded by an underscore.
|
||||
</p>
|
||||
|
||||
<p>
|
||||
<em>Updating</em>: Packages that depend on the old behavior will no longer compile correctly.
|
||||
Files with names like <code>windows.go</code> or <code>arm64.go</code> should either
|
||||
have explicit build tags added to the source or be renamed to something like
|
||||
<code>os_windows.go</code> or <code>support_arm64.go</code>.
|
||||
</p>
|
||||
|
||||
<h3 id="gocmd">Other changes to the go command</h3>
|
||||
|
||||
<p>
|
||||
There were a number of minor changes to the
|
||||
<a href="/cmd/go/"><code>cmd/go</code></a>
|
||||
command worth noting.
|
||||
</p>
|
||||
|
||||
<ul>
|
||||
|
||||
<li>
|
||||
Unless <a href="/cmd/cgo/"><code>cgo</code></a> is being used to build the package,
|
||||
the <code>go</code> command now refuses to compile C source files,
|
||||
since the relevant C compilers
|
||||
(<a href="/cmd/6c/"><code>6c</code></a> etc.)
|
||||
are intended to be removed from the installation in some future release.
|
||||
(They are used today only to build part of the runtime.)
|
||||
It is difficult to use them correctly in any case, so any extant uses are likely incorrect,
|
||||
so we have disabled them.
|
||||
</li>
|
||||
|
||||
<li>
|
||||
The <a href="/cmd/go/#hdr-Test_packages"><code>go</code> <code>test</code></a>
|
||||
subcommand has a new flag, <code>-o</code>, to set the name of the resulting binary,
|
||||
corresponding to the same flag in other subcommands.
|
||||
The non-functional <code>-file</code> flag has been removed.
|
||||
</li>
|
||||
|
||||
<li>
|
||||
The <a href="/cmd/go/#hdr-Test_packages"><code>go</code> <code>test</code></a>
|
||||
will compile and link all <code>*_test.go</code> files in the package,
|
||||
even when there are no <code>Test</code> functions in them.
|
||||
It previously ignored such files.
|
||||
</li>
|
||||
|
||||
<li>
|
||||
The behavior of the
|
||||
<a href="/cmd/go/#hdr-Test_packages"><code>go</code> <code>build</code></a>'s
|
||||
<code>-a</code> flag has been changed for non-development installations.
|
||||
For installations running a released distribution, the <code>-a</code> flag will no longer
|
||||
rebuild the standard library and commands, to avoid overwriting the installation's files.
|
||||
</li>
|
||||
|
||||
</ul>
|
||||
|
||||
<h3 id="cgo">Changes to cgo</h3>
|
||||
|
||||
<p>
|
||||
@ -285,14 +369,6 @@ See the relevant package documentation for more information about each change.
|
||||
<pre>
|
||||
|
||||
cmd/6l, liblink: use pc-relative addressing for all memory references, so that linking Go binaries at high addresses works (CL 125140043). This cuts the maximum size of a Go binary's text+data+bss from 4GB to 2GB.
|
||||
cmd/go: import comments (CL 124940043)
|
||||
cmd/go: implement "internal" (CL 120600043)
|
||||
cmd/go: implement "generate" (CL 125580044)
|
||||
cmd/go: disallow C sources except when using cgo (CL 149720043)
|
||||
cmd/go: add test -o flag (CL 149070043)
|
||||
cmd/go: redefine build -a to skip standard library in releases (CL 151730045)
|
||||
cmd/go: compile and link all _test.go files during 'go test', even in packages where there are no Test functions (CL 150980043)
|
||||
cmd/go: (via go/build): a GOOS prefix acts as a tag only if preceded by an underscore. this is a breaking change. (CL 147690043)
|
||||
|
||||
asm: make textflag.h available outside of cmd/ld (CL 128050043)
|
||||
bufio: handling of empty tokens at EOF changed, may require scanner change (CL 145390043)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user