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doc/go1.11: compiler and runtime release notes

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Change-Id: I487bdf0c828d28b2122bd93934dc5a9a5dbc6a00
Reviewed-on: https://go-review.googlesource.com/124517
Reviewed-by: Austin Clements <austin@google.com>
This commit is contained in:
Austin Clements 2018-07-17 17:49:37 -04:00
parent 61a04474e2
commit 92e03bbaa8
1 changed files with 141 additions and 67 deletions
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208
doc/go1.11.html
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@ -45,6 +45,11 @@ Do not send CLs removing the interior tags from such phrases.
Support for previous versions of these operating systems has been removed.
</p>
<p> <!-- CL 121657 -->
Go 1.11 supports the upcoming OpenBSD 6.4 release. Due to changes in
the OpenBSD kernel, older versions of Go will not work on OpenBSD 6.4.
</p>
<p>
There are <a href="https://golang.org/issue/25206">known issues</a> with NetBSD on i386 hardware.
</p>
@ -55,6 +60,10 @@ Do not send CLs removing the interior tags from such phrases.
has <a href="https://golang.org/issue/26403">known issues</a>.
</p>
<p><!-- CL 109255 -->
The memory sanitizer (<code>-msan</code>) is now supported on <code>linux/arm64</code>.
</p>
<p><!-- CL 93875 -->
The build modes <code>c-shared</code> and <code>c-archive</code> are now supported on
<code>freebsd/amd64</code>.
@ -69,6 +78,21 @@ Do not send CLs removing the interior tags from such phrases.
as <a href="go1.10#mips">added in Go 1.10</a>.
</p>
<p><!-- CL 107475 -->
On soft-float ARM systems (<code>GOARM=5</code>), Go now uses a more
efficient software floating point interface. This is transparent to
Go code, but ARM assembly that uses floating-point instructions not
guarded on GOARM will break and must be ported to
the <a href="https://golang.org/cl/107475">new interface</a>.
</p>
<p><!-- CL 94076 -->
Go 1.11 on ARMv7 no longer requires a Linux kernel configured
with <code>KUSER_HELPERS</code>. This setting is enabled in default
kernel configurations, but is sometimes disabled in stripped-down
configurations.
</p>
<h3 id="wasm">WebAssembly</h3>
<p>
Go 1.11 adds an experimental port to WebAssembly (<code>js/wasm</code>).
@ -157,6 +181,88 @@ Do not send CLs removing the interior tags from such phrases.
please <a href="https://golang.org/issue/new">file an issue</a> to let us know about them.
</p>
<h3 id="compiler">Compiler toolchain</h3>
<p><!-- CL 109918 -->
More functions are now eligible for inlining by default, including
functions that call <code>panic</code>.
</p>
<p><!-- CL 97375 -->
The compiler toolchain now supports column information
in <a href="/cmd/compile/#hdr-Compiler_Directives">line
directives</a>.
</p>
<p><!-- CL 106797 -->
A new package export data format has been introduced.
This should be transparent to end users, except for speeding up
build times for large Go projects.
If it does cause problems, it can be turned off again by
passing <code>-gcflags=all=-iexport=false</code> to
the <code>go</code> tool when building a binary.
</p>
<p><!-- CL 100459 -->
The compiler now rejects unused variables declared in a type switch
guard, such as <code>x</code> in the following example:
</p>
<pre>
func f(v interface{}) {
switch x := v.(type) {
}
}
</pre>
<p>
This was already rejected by both <code>gccgo</code>
and <a href="/pkg/go/types/">go/types</a>.
</p>
<h3 id="assembler">Assembler</h3>
<p><!-- CL 113315 -->
The assembler for <code>amd64</code> now accepts AVX512 instructions.
</p>
<h3 id="debugging">Debugging</h3>
<p><!-- CL 100738, CL 93664 -->
The compiler now produces significantly more accurate debug
information for optimized binaries, including variable location
information, line numbers, and breakpoint locations.
This should make it possible to debug binaries
compiled <em>without</em> <code>-N</code>&nbsp;<code>-l</code>.
There are still limitations to the quality of the debug information,
some of which are fundamental, and some of which will continue to
improve with future releases.
</p>
<p><!-- CL 118276 -->
DWARF sections are now compressed by default because of the expanded
and more accurate debug information produced by the compiler.
This is transparent to most ELF tools (such as debuggers on Linux
and *BSD) and is supported by the Delve debugger on all platforms,
but has limited support in the native tools on macOS and Windows.
To disable DWARF compression,
pass <code>-ldflags=-compressdwarf=false</code> to
the <code>go</code> tool when building a binary.
</p>
<p><!-- CL 109699 -->
Go 1.11 adds experimental support for calling Go functions from
within a debugger.
This is useful, for example, to call <code>String</code> methods
when paused at a breakpoint.
<!-- TODO(austin): Make sure methods calls are actually supported by Delve -->
This is currently only supported by Delve.
</p>
<h2 id="tools">Tools</h2>
<h3 id="test">Test</h3>
@ -175,6 +281,12 @@ Do not send CLs removing the interior tags from such phrases.
"unused variable" error in this case.
</p>
<p><!-- CL 102696 -->
The <code>-memprofile</code> flag
to <code>go</code>&nbsp;<code>test</code> now defaults to the
"allocs" profile, which records the total bytes allocated since the
test began (including garbage-collected bytes).
</p>
<h3 id="vet">Vet</h3>
@ -185,6 +297,22 @@ Do not send CLs removing the interior tags from such phrases.
a warning to be printed, and <code>vet</code> to exit with status 1.
</p>
<h2 id="runtime">Runtime</h2>
<p><!-- CL 85887 -->
The runtime now uses a sparse heap layout so there is no longer a
limit to the size of the Go heap (previously, the limit was 512GiB).
This also fixes rare "address space conflict" failures in mixed Go/C
binaries or binaries compiled with <code>-race</code>.
</p>
<p><!-- CL 108679 -->
On macOS, the runtime now uses <code>libSystem.so</code> instead of
calling the kernel directly. This should make Go binaries more
compatible with future versions of macOS.
The <a href="/pkg/syscall">syscall</a> package still makes direct
system calls; fixing this is planned for a future release.
</p>
<h2 id="library">Core library</h2>
@ -200,17 +328,8 @@ Do not send CLs removing the interior tags from such phrases.
in mind.
</p>
<!-- CL 113315: https://golang.org/cl/113315: cmd/asm: enable AVX512 -->
<!-- CL 100459: https://golang.org/cl/100459: cmd/compile: reject type switch with guarded declaration and no cases -->
<!-- CL 100738: https://golang.org/cl/100738: cmd/compile: turn on DWARF locations lists for ssa vars -->
<!-- CL 106797: https://golang.org/cl/106797: cmd/compile: enable indexed export format by default -->
<!-- CL 109918: https://golang.org/cl/109918: More functions are now eligible for inlining by default, including functions that call panic.: cmd/compile: refactor inlining parameters; inline panic -->
<!-- CL 97375: https://golang.org/cl/97375: cmd/compile, cmd/compile/internal/syntax: print relative column info -->
<!-- CL 115095: https://golang.org/cl/115095: yes (`go test pkg` now always builds pkg even if there are no test files): cmd/go: output coverage report even if there are no test files -->
<!-- CL 110395: https://golang.org/cl/110395: cmd/go, cmd/compile: use Windows response files to avoid arg length limits -->
<!-- CL 107475: https://golang.org/cl/107475: cmd/internal/obj/arm, runtime: delete old ARM softfloat code -->
<!-- CL 93664: https://golang.org/cl/93664: cmd/link: process is_stmt data into dwarf line tables -->
<!-- CL 118276: https://golang.org/cl/118276: yes here?: cmd/link: compress DWARF sections in ELF binaries -->
<!-- CL 112436: https://golang.org/cl/112436: cmd/pprof: add readline support similar to upstream -->
@ -523,48 +642,27 @@ Do not send CLs removing the interior tags from such phrases.
<dl id="runtime"><dt><a href="/pkg/runtime/">runtime</a></dt>
<dd>
<p><!-- CL 85887 -->
TODO: <a href="https://golang.org/cl/85887">https://golang.org/cl/85887</a>: use sparse mappings for the heap
</p>
<p><!-- CL 94076 -->
TODO: <a href="https://golang.org/cl/94076">https://golang.org/cl/94076</a>: use native CAS and memory barrier on ARMv7
</p>
<p><!-- CL 106156 -->
TODO: <a href="https://golang.org/cl/106156">https://golang.org/cl/106156</a>: use fixed TLS offsets on darwin/amd64 and darwin/386
</p>
<p><!-- CL 109255 -->
TODO: <a href="https://golang.org/cl/109255">https://golang.org/cl/109255</a>: enable memory sanitizer on arm64
</p>
<p><!-- CL 109699 -->
TODO: <a href="https://golang.org/cl/109699">https://golang.org/cl/109699</a>: support for debugger function calls
</p>
<p><!-- CL 121657 -->
TODO: <a href="https://golang.org/cl/121657">https://golang.org/cl/121657</a>: remap stack spans with MAP_STACK on OpenBSD
</p>
<p><!-- CL 70993 -->
TODO: <a href="https://golang.org/cl/70993">https://golang.org/cl/70993</a>: support tracking goroutine ancestor tracebacks with GODEBUG=&#34;tracebackancestors=N&#34;
Setting the <code>GODEBUG=tracebackancestors=<em>N</em></code>
environment variable now extends tracebacks with the stacks at
which goroutines were created, where <em>N</em> limits the
number of ancestor goroutines to report.
</p>
</dl><!-- runtime -->
<dl id="runtime,cmd/ld"><dt><a href="/pkg/runtime,cmd/ld/">runtime,cmd/ld</a></dt>
<dd>
<p><!-- CL 108679 -->
TODO: <a href="https://golang.org/cl/108679">https://golang.org/cl/108679</a>: on darwin, create theads using libc
</p>
</dl><!-- runtime,cmd/ld -->
<dl id="runtime/pprof"><dt><a href="/pkg/runtime/pprof/">runtime/pprof</a></dt>
<dd>
<p><!-- CL 102696 -->
TODO: <a href="https://golang.org/cl/102696">https://golang.org/cl/102696</a>: introduce &#34;allocs&#34; profile
This release adds a new "allocs" profile type that profiles
total number of bytes allocated since the program began
(including garbage-collected bytes). This is identical to the
existing "heap" profile viewed in <code>-alloc_space</code>
mode.
</p>
</dl><!-- runtime/pprof -->
@ -577,37 +675,13 @@ Do not send CLs removing the interior tags from such phrases.
</dl><!-- runtime/trace -->
</dl><!-- regexp -->
<dl id="runtime,cmd/ld"><dt><a href="/pkg/runtime,cmd/ld/">runtime,cmd/ld</a></dt>
<dd>
<p><!-- CL 108679 -->
TODO: <a href="https://golang.org/cl/108679">https://golang.org/cl/108679</a>: on darwin, create theads using libc
</p>
</dl><!-- runtime,cmd/ld -->
<dl id="runtime/trace"><dt><a href="/pkg/runtime/trace/">runtime/trace</a></dt>
<dd>
<p><!-- CL 63274 -->
TODO: <a href="https://golang.org/cl/63274">https://golang.org/cl/63274</a>: user annotation API
</p>
</dl><!-- runtime/trace -->
<dl id="runtime/traceback"><dt><a href="/pkg/runtime/traceback/">runtime/traceback</a></dt>
<dd>
<p><!-- CL 70993 -->
TODO: <a href="https://golang.org/cl/70993">https://golang.org/cl/70993</a>: support tracking goroutine ancestor tracebacks with GODEBUG=&#34;tracebackancestors=N&#34;
</p>
</dl><!-- runtime/traceback -->
<dl id="sync"><dt><a href="/pkg/sync/">sync</a></dt>
<dd>
<p><!-- CL 87095 -->
TODO: <a href="https://golang.org/cl/87095">https://golang.org/cl/87095</a>: enable profiling of RWMutex
The mutex profile now includes reader/writer contention
for <a href="/pkg/sync/#RWMutex"><code>RWMutex</code>.
Writer/writer contention was already included in the mutex
profile.
</p>
</dl><!-- sync -->