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Diffstat (limited to 'doc')
| -rw-r--r-- | doc/articles/race_detector.html | 2 | ||||
| -rw-r--r-- | doc/contribute.html | 21 | ||||
| -rw-r--r-- | doc/diagnostics.html | 2 | ||||
| -rw-r--r-- | doc/go1.16.html | 892 | ||||
| -rw-r--r-- | doc/go1.html | 4 | ||||
| -rw-r--r-- | doc/go_spec.html | 44 | ||||
| -rw-r--r-- | doc/install-source.html | 85 |
7 files changed, 939 insertions, 111 deletions
diff --git a/doc/articles/race_detector.html b/doc/articles/race_detector.html index 63a658f870..09188c15d5 100644 --- a/doc/articles/race_detector.html +++ b/doc/articles/race_detector.html @@ -418,7 +418,7 @@ close(c) <code>linux/amd64</code>, <code>linux/ppc64le</code>, <code>linux/arm64</code>, <code>freebsd/amd64</code>, <code>netbsd/amd64</code>, <code>darwin/amd64</code>, - and <code>windows/amd64</code>. + <code>darwin/arm64</code>, and <code>windows/amd64</code>. </p> <h2 id="Runtime_Overheads">Runtime Overhead</h2> diff --git a/doc/contribute.html b/doc/contribute.html index 03d02c9d75..f297477fe0 100644 --- a/doc/contribute.html +++ b/doc/contribute.html @@ -45,8 +45,8 @@ CLA (Contributor License Agreement). </li> <li> <b>Step 2</b>: Configure authentication credentials for the Go Git repository. -Visit <a href="https://go.googlesource.com/">go.googlesource.com</a>, click -on the gear icon (top right), then on "Obtain password", and follow the +Visit <a href="https://go.googlesource.com">go.googlesource.com</a>, click +"Generate Password" in the page's top right menu bar, and follow the instructions. </li> <li> @@ -806,10 +806,9 @@ tracker will automatically mark the issue as fixed. <p> If the change is a partial step towards the resolution of the issue, -uses the notation "Updates #12345". -This will leave a comment in the issue -linking back to the change in Gerrit, but it will not close the issue -when the change is applied. +write "Updates #12345" instead. +This will leave a comment in the issue linking back to the change in +Gerrit, but it will not close the issue when the change is applied. </p> <p> @@ -948,10 +947,18 @@ The Gerrit voting system involves an integer in the range -2 to +2: </li> </ul> +<p> +At least two maintainers must approve of the change, and at least one +of those maintainers must +2 the change. +The second maintainer may cast a vote of Trust+1, meaning that the +change looks basically OK, but that the maintainer hasn't done the +detailed review required for a +2 vote. +</p> + <h3 id="submit">Submitting an approved change</h3> <p> -After the code has been +2'ed, an approver will +After the code has been +2'ed and Trust+1'ed, an approver will apply it to the master branch using the Gerrit user interface. This is called "submitting the change". </p> diff --git a/doc/diagnostics.html b/doc/diagnostics.html index 478611c15c..438cdce45f 100644 --- a/doc/diagnostics.html +++ b/doc/diagnostics.html @@ -454,6 +454,8 @@ environmental variable is set accordingly.</p> <li>GODEBUG=gctrace=1 prints garbage collector events at each collection, summarizing the amount of memory collected and the length of the pause.</li> +<li>GODEBUG=inittrace=1 prints a summary of execution time and memory allocation +information for completed package initialization work.</li> <li>GODEBUG=schedtrace=X prints scheduling events every X milliseconds.</li> </ul> diff --git a/doc/go1.16.html b/doc/go1.16.html index 0ffaecc5a9..2ff763f9b6 100644 --- a/doc/go1.16.html +++ b/doc/go1.16.html @@ -26,61 +26,395 @@ Do not send CLs removing the interior tags from such phrases. <h2 id="language">Changes to the language</h2> <p> - TODO + There are no changes to the language. </p> <h2 id="ports">Ports</h2> -<p> - TODO +<h3 id="darwin">Darwin and iOS</h3> + +<p><!-- golang.org/issue/38485, golang.org/issue/41385, CL 266373, more CLs --> + Go 1.16 adds support of 64-bit ARM architecture on macOS (also known as + Apple Silicon) with <code>GOOS=darwin</code>, <code>GOARCH=arm64</code>. + Like the <code>darwin/amd64</code> port, the <code>darwin/arm64</code> + port supports cgo, internal and external linking, <code>c-archive</code>, + <code>c-shared</code>, and <code>pie</code> build modes, and the race + detector. </p> -<h2 id="tools">Tools</h2> +<p><!-- CL 254740 --> + The iOS port, which was previously <code>darwin/arm64</code>, has + been renamed to <code>ios/arm64</code>. <code>GOOS=ios</code> + implies the + <code>darwin</code> build tag, just as <code>GOOS=android</code> + implies the <code>linux</code> build tag. This change should be + transparent to anyone using gomobile to build iOS apps. +</p> -<p> - TODO +<p><!-- golang.org/issue/42100, CL 263798 --> + Go 1.16 adds an <code>ios/amd64</code> port, which targets the iOS + simulator running on AMD64-based macOS. Previously this was + unofficially supported through <code>darwin/amd64</code> with + the <code>ios</code> build tag set. +</p> + +<p><!-- golang.org/issue/23011 --> + Go 1.16 is the last release that will run on macOS 10.12 Sierra. + Go 1.17 will require macOS 10.13 High Sierra or later. +</p> + +<h3 id="netbsd">NetBSD</h3> + +<p><!-- golang.org/issue/30824 --> + Go now supports the 64-bit ARM architecture on NetBSD (the + <code>netbsd/arm64</code> port). +</p> + +<h3 id="openbsd">OpenBSD</h3> + +<p><!-- golang.org/issue/40995 --> + Go now supports the MIPS64 architecture on OpenBSD + (the <code>openbsd/mips64</code> port). This port does not yet + support cgo. +</p> + +<h3 id="386">386</h3> + +<p><!-- golang.org/issue/40255, golang.org/issue/41848, CL 258957, and CL 260017 --> + As <a href="go1.15#386">announced</a> in the Go 1.15 release notes, + Go 1.16 drops support for x87 mode compilation (<code>GO386=387</code>). + Support for non-SSE2 processors is now available using soft float + mode (<code>GO386=softfloat</code>). + Users running on non-SSE2 processors should replace <code>GO386=387</code> + with <code>GO386=softfloat</code>. </p> +<h3 id="riscv">RISC-V</h3> + +<p><!-- golang.org/issue/36641, CL 267317 --> + The <code>linux/riscv64</code> port now supports cgo and + <code>-buildmode=pie</code>. This release also includes performance + optimizations and code generation improvements for RISC-V. +</p> + +<h2 id="tools">Tools</h2> + <h3 id="go-command">Go command</h3> +<h4 id="modules">Modules</h4> + +<p><!-- golang.org/issue/41330 --> + Module-aware mode is enabled by default, regardless of whether a + <code>go.mod</code> file is present in the current working directory or a + parent directory. More precisely, the <code>GO111MODULE</code> environment + variable now defaults to <code>on</code>. To switch to the previous behavior, + set <code>GO111MODULE</code> to <code>auto</code>. +</p> + +<p><!-- golang.org/issue/40728 --> + Build commands like <code>go</code> <code>build</code> and <code>go</code> + <code>test</code> no longer modify <code>go.mod</code> and <code>go.sum</code> + by default. Instead, they report an error if a module requirement or checksum + needs to be added or updated (as if the <code>-mod=readonly</code> flag were + used). Module requirements and sums may be adjusted with <code>go</code> + <code>mod</code> <code>tidy</code> or <code>go</code> <code>get</code>. +</p> + +<p><!-- golang.org/issue/40276 --> + <code>go</code> <code>install</code> now accepts arguments with + version suffixes (for example, <code>go</code> <code>install</code> + <code>example.com/cmd@v1.0.0</code>). This causes <code>go</code> + <code>install</code> to build and install packages in module-aware mode, + ignoring the <code>go.mod</code> file in the current directory or any parent + directory, if there is one. This is useful for installing executables without + affecting the dependencies of the main module. +</p> + +<p><!-- golang.org/issue/40276 --> + <code>go</code> <code>install</code>, with or without a version suffix (as + described above), is now the recommended way to build and install packages in + module mode. <code>go</code> <code>get</code> should be used with the + <code>-d</code> flag to adjust the current module's dependencies without + building packages, and use of <code>go</code> <code>get</code> to build and + install packages is deprecated. In a future release, the <code>-d</code> flag + will always be enabled. +</p> + <p><!-- golang.org/issue/24031 --> <code>retract</code> directives may now be used in a <code>go.mod</code> file to indicate that certain published versions of the module should not be used by other modules. A module author may retract a version after a severe problem is discovered or if the version was published unintentionally.<br> - TODO: write and link to section in golang.org/ref/mod<br> - TODO: write and link to tutorial or blog post </p> -<p><!-= golang.org/issue/29062 --> - When using <code>go test</code>, a test that +<p><!-- golang.org/issue/26603 --> + The <code>go</code> <code>mod</code> <code>vendor</code> + and <code>go</code> <code>mod</code> <code>tidy</code> subcommands now accept + the <code>-e</code> flag, which instructs them to proceed despite errors in + resolving missing packages. +</p> + +<p><!-- golang.org/issue/36465 --> + The <code>go</code> command now ignores requirements on module versions + excluded by <code>exclude</code> directives in the main module. Previously, + the <code>go</code> command used the next version higher than an excluded + version, but that version could change over time, resulting in + non-reproducible builds. +</p> + +<h4 id="embed">Embedding Files</h4> + +<p> + The <code>go</code> command now supports including + static files and file trees as part of the final executable, + using the new <code>//go:embed</code> directive. + See the documentation for the new + <a href="/pkg/embed/"><code>embed</code></a> + package for details. +</p> + +<h4 id="go-test"><code>go</code> <code>test</code></h4> + +<p><!-- golang.org/issue/29062 --> + When using <code>go</code> <code>test</code>, a test that calls <code>os.Exit(0)</code> during execution of a test function will now be considered to fail. This will help catch cases in which a test calls code that calls - os.Exit(0) and thereby stops running all future tests. + <code>os.Exit(0)</code> and thereby stops running all future tests. If a <code>TestMain</code> function calls <code>os.Exit(0)</code> that is still considered to be a passing test. </p> +<p><!-- golang.org/issue/39484 --> + <code>go</code> <code>test</code> reports an error when the <code>-c</code> + or <code>-i</code> flags are used together with unknown flags. Normally, + unknown flags are passed to tests, but when <code>-c</code> or <code>-i</code> + are used, tests are not run. +</p> + +<h4 id="go-get"><code>go</code> <code>get</code></h4> + +<p><!-- golang.org/issue/37519 --> + The <code>go</code> <code>get</code> <code>-insecure</code> flag is + deprecated and will be removed in a future version. This flag permits + fetching from repositories and resolving custom domains using insecure + schemes such as HTTP, and also bypasses module sum validation using the + checksum database. To permit the use of insecure schemes, use the + <code>GOINSECURE</code> environment variable instead. To bypass module + sum validation, use <code>GOPRIVATE</code> or <code>GONOSUMDB</code>. + See <code>go</code> <code>help</code> <code>environment</code> for details. +</p> + +<p><!-- golang.org/cl/263267 --> + <code>go</code> <code>get</code> <code>example.com/mod@patch</code> now + requires that some version of <code>example.com/mod</code> already be + required by the main module. + (However, <code>go</code> <code>get</code> <code>-u=patch</code> continues + to patch even newly-added dependencies.) +</p> + +<h4 id="govcs"><code>GOVCS</code> environment variable</h4> + +<p><!-- golang.org/issue/266420 --> + <code>GOVCS</code> is a new environment variable that limits which version + control tools the <code>go</code> command may use to download source code. + This mitigates security issues with tools that are typically used in trusted, + authenticated environments. By default, <code>git</code> and <code>hg</code> + may be used to download code from any repository. <code>svn</code>, + <code>bzr</code>, and <code>fossil</code> may only be used to download code + from repositories with module paths or package paths matching patterns in + the <code>GOPRIVATE</code> environment variable. See + <a href="/cmd/go/#hdr-Controlling_version_control_with_GOVCS"><code>go</code> + <code>help</code> <code>vcs</code></a> for details. +</p> + +<h4 id="all-pattern">The <code>all</code> pattern</h4> + +<p><!-- golang.org/cl/240623 --> + When the main module's <code>go.mod</code> file + declares <code>go</code> <code>1.16</code> or higher, the <code>all</code> + package pattern now matches only those packages that are transitively imported + by a package or test found in the main module. (Packages imported by <em>tests + of</em> packages imported by the main module are no longer included.) This is + the same set of packages retained + by <code>go</code> <code>mod</code> <code>vendor</code> since Go 1.11. +</p> + +<h4 id="toolexec">The <code>-toolexec</code> build flag</h4> + +<p><!-- golang.org/cl/263357 --> + When the <code>-toolexec</code> build flag is specified to use a program when + invoking toolchain programs like compile or asm, the environment variable + <code>TOOLEXEC_IMPORTPATH</code> is now set to the import path of the package + being built. +</p> + +<h4 id="i-flag">The <code>-i</code> build flag</h4> + +<p><!-- golang.org/issue/41696 --> + The <code>-i</code> flag accepted by <code>go</code> <code>build</code>, + <code>go</code> <code>install</code>, and <code>go</code> <code>test</code> is + now deprecated. The <code>-i</code> flag instructs the <code>go</code> command + to install packages imported by packages named on the command line. Since + the build cache was introduced in Go 1.10, the <code>-i</code> flag no longer + has a significant effect on build times, and it causes errors when the install + directory is not writable. +</p> + +<h4 id="list-buildid">The <code>list</code> command</h4> + +<p><!-- golang.org/cl/263542 --> + When the <code>-export</code> flag is specified, the <code>BuildID</code> + field is now set to the build ID of the compiled package. This is equivalent + to running <code>go</code> <code>tool</code> <code>buildid</code> on + <code>go</code> <code>list</code> <code>-exported</code> <code>-f</code> <code>{{.Export}</code>, + but without the extra step. +</p> + +<h4 id="overlay-flag">The <code>-overlay</code> flag</h4> + +<p><!-- golang.org/issue/39958 --> + The <code>-overlay</code> flag specifies a JSON configuration file containing + a set of file path replacements. The <code>-overlay</code> flag may be used + with all build commands and <code>go</code> <code>mod</code> subcommands. + It is primarily intended to be used by editor tooling such as gopls to + understand the effects of unsaved changes to source files. The config file + maps actual file paths to replacement file paths and the <code>go</code> + command and its builds will run as if the actual file paths exist with the + contents given by the replacement file paths, or don't exist if the replacement + file paths are empty. +</p> + +<h3 id="cgo">Cgo</h3> + +<p><!-- CL 252378 --> + The <a href="/cmd/cgo">cgo</a> tool will no longer try to translate + C struct bitfields into Go struct fields, even if their size can be + represented in Go. The order in which C bitfields appear in memory + is implementation dependent, so in some cases the cgo tool produced + results that were silently incorrect. +</p> + +<h3 id="vet">Vet</h3> + +<h4 id="vet-string-int">New warning for invalid testing.T use in +goroutines</h4> + +<p><!-- CL 235677 --> + The vet tool now warns about invalid calls to the <code>testing.T</code> + method <code>Fatal</code> from within a goroutine created during the test. + This also warns on calls to <code>Fatalf</code>, <code>FailNow</code>, and + <code>Skip{,f,Now}</code> methods on <code>testing.T</code> tests or + <code>testing.B</code> benchmarks. +</p> + +<p> + Calls to these methods stop the execution of the created goroutine and not + the <code>Test*</code> or <code>Benchmark*</code> function. So these are + <a href="/pkg/testing/#T.FailNow">required</a> to be called by the goroutine + running the test or benchmark function. For example: +</p> + +<pre> +func TestFoo(t *testing.T) { + go func() { + if condition() { + t.Fatal("oops") // This exits the inner func instead of TestFoo. + } + ... + }() +} +</pre> + <p> - TODO + Code calling <code>t.Fatal</code> (or a similar method) from a created + goroutine should be rewritten to signal the test failure using + <code>t.Error</code> and exit the goroutine early using an alternative + method, such as using a <code>return</code> statement. The previous example + could be rewritten as: +</p> + +<pre> +func TestFoo(t *testing.T) { + go func() { + if condition() { + t.Error("oops") + return + } + ... + }() +} +</pre> + +<p><!-- CL 248686, CL 276372 --> + The vet tool now warns about amd64 assembly that clobbers the BP + register (the frame pointer) without saving and restoring it, + contrary to the calling convention. Code that doesn't preserve the + BP register must be modified to either not use BP at all or preserve + BP by saving and restoring it. An easy way to preserve BP is to set + the frame size to a nonzero value, which causes the generated + prologue and epilogue to preserve the BP register for you. + See <a href="https://golang.org/cl/248260">CL 248260</a> for example + fixes. </p> <h2 id="runtime">Runtime</h2> <p> - TODO + The new <a href="/pkg/runtime/metrics/"><code>runtime/metrics</code></a> package + introduces a stable interface for reading + implementation-defined metrics from the Go runtime. + It supersedes existing functions like + <a href="/pkg/runtime/#ReadMemStats"><code>runtime.ReadMemStats</code></a> + and + <a href="/pkg/runtime/debug/#GCStats"><code>debug.GCStats</code></a> + and is significantly more general and efficient. + See the package documentation for more details. +</p> + +<p><!-- CL 254659 --> + Setting the <code>GODEBUG</code> environment variable + to <code>inittrace=1</code> now causes the runtime to emit a single + line to standard error for each package <code>init</code>, + summarizing its execution time and memory allocation. This trace can + be used to find bottlenecks or regressions in Go startup + performance. + The <a href="/pkg/runtime/#hdr-Environment_Variables"><code>GODEBUG</code>< + documentation</a> describes the format. +</p> + +<p><!-- CL 267100 --> + On Linux, the runtime now defaults to releasing memory to the + operating system promptly (using <code>MADV_DONTNEED</code>), rather + than lazily when the operating system is under memory pressure + (using <code>MADV_FREE</code>). This means process-level memory + statistics like RSS will more accurately reflect the amount of + physical memory being used by Go processes. Systems that are + currently using <code>GODEBUG=madvdontneed=1</code> to improve + memory monitoring behavior no longer need to set this environment + variable. +</p> + +<p><!-- CL 220419, CL 271987 --> + Go 1.16 fixes a discrepancy between the race detector and + the <a href="/ref/mem">Go memory model</a>. The race detector now + more precisely follows the channel synchronization rules of the + memory model. As a result, the detector may now report races it + previously missed. </p> <h2 id="compiler">Compiler</h2> -<p> - TODO +<p><!-- CL 256459, CL 264837, CL 266203, CL 256460 --> + The compiler can now inline functions with + non-labeled <code>for</code> loops, method values, and type + switches. The inliner can also detect more indirect calls where + inlining is possible. </p> <h2 id="linker">Linker</h2> -<p> +<p><!-- CL 248197 --> This release includes additional improvements to the Go linker, reducing linker resource usage (both time and memory) and improving code robustness/maintainability. These changes form the second half @@ -94,54 +428,74 @@ Do not send CLs removing the interior tags from such phrases. supported architecture/OS combinations (the 1.15 performance improvements were primarily focused on <code>ELF</code>-based OSes and <code>amd64</code> architectures). For a representative set of - large Go programs, linking is 20-35% faster than 1.15 and requires + large Go programs, linking is 20-25% faster than 1.15 and requires 5-15% less memory on average for <code>linux/amd64</code>, with larger - improvements for other architectures and OSes. + improvements for other architectures and OSes. Most binaries are + also smaller as a result of more aggressive symbol pruning. </p> -<p> - TODO: update with final numbers later in the release. +<p><!-- CL 255259 --> + On Windows, <code>go build -buildmode=c-shared</code> now generates Windows + ASLR DLLs by default. ASLR can be disabled with <code>--ldflags=-aslr=false</code>. </p> <h2 id="library">Core library</h2> +<h3 id="library-embed">Embedded Files</h3> + <p> - TODO + The new <a href="/pkg/embed/"><code>embed</code></a> package + provides access to files embedded in the program during compilation + using the new <a href="#embed"><code>//go:embed</code> directive</a>. </p> -<h3 id="net"><a href="/pkg/net/">net</a></h3> +<h3 id="fs">File Systems</h3> -<p><!-- CL 250357 --> - The case of I/O on a closed network connection, or I/O on a network - connection that is closed before any of the I/O completes, can now - be detected using the new <a href="/pkg/net/#ErrClosed">ErrClosed</a> error. - A typical use would be <code>errors.Is(err, net.ErrClosed)</code>. - In earlier releases the only way to reliably detect this case was to - match the string returned by the <code>Error</code> method - with <code>"use of closed network connection"</code>. +<p> + The new <a href="/pkg/io/fs/"><code>io/fs</code></a> package + defines an abstraction for read-only trees of files, + the <a href="/pkg/io/fs/#FS"><code>fs.FS</code></a> interface, + and the standard library packages have + been adapted to make use of the interface as appropriate. </p> - -<h3 id="text/template/parse"><a href="/pkg/text/template/parse/">text/template/parse</a></h3> - -<p><!-- CL 229398, golang.org/issue/34652 --> - A new <a href="/pkg/text/template/parse/#CommentNode"><code>CommentNode</code></a> - was added to the parse tree. The <a href="/pkg/text/template/parse/#Mode"><code>Mode</code></a> - field in the <code>parse.Tree</code> enables access to it. +<p> + On the producer side of the interface, + the new <a href="/pkg/embed/#FS">embed.FS</code></a> type + implements <code>fs.FS</code>, as does + <a href="/pkg/archive/zip/#Reader"><code>zip.Reader</code></a>. + The new <a href="/pkg/os/#DirFS"><code>os.DirFS</code></a> function + provides an implementation of <code>fs.FS</code> backed by a tree + of operating system files. </p> -<!-- text/template/parse --> -<h3 id="unicode"><a href="/pkg/unicode/">unicode</a></h3> +<p> + On the consumer side, + the new <a href="/pkg/net/http/#FS"><code>http.FS</code></a> + function converts an <code>fs.FS</code> to an + <a href="/pkg/net/http/#Handler"><code>http.Handler</code></a>. + Also, the <a href="/pkg/html/template/"><code>html/template</code></a> + and <a href="/pkg/text/template/"><code>text/template</code></a> + packages’ <a href="/pkg/html/template/#ParseFS"><code>ParseFS</code></a> + functions and methods read templates from an <code>fs.FS</code>. +</p> -<p><!-- CL 248765 --> - The <a href="/pkg/unicode/"><code>unicode</code></a> package and associated - support throughout the system has been upgraded from Unicode 12.0.0 to - <a href="https://www.unicode.org/versions/Unicode13.0.0/">Unicode 13.0.0</a>, - which adds 5,930 new characters, including four new scripts, and 55 new emoji. - Unicode 13.0.0 also designates plane 3 (U+30000-U+3FFFF) as the tertiary - ideographic plane. +<p> + For testing code that implements <code>fs.FS</code>, + the new <a href="/pkg/testing/fstest/"><code>testing/fstest</code></a> + package provides a <a href="/pkg/testing/fstest/#TestFS"><code>TestFS</code></a> + function that checks for and reports common mistakes. + It also provides a simple in-memory file system implementation, + <a href="/pkg/testing/fstest/#MapFS"><code>MapFS</code></a>, + which can be useful for testing code that accepts <code>fs.FS</code> + implementations. </p> +<!-- okay-after-beta1 + TODO: decide if any additional changes are worth factoring out from + "Minor changes to the library" and highlighting in "Core library" +--> + <h3 id="minor_library_changes">Minor changes to the library</h3> <p> @@ -150,9 +504,244 @@ Do not send CLs removing the interior tags from such phrases. in mind. </p> -<p> - TODO -</p> +<dl id="crypto/dsa"><dt><a href="/pkg/crypto/dsa/">crypto/dsa</a></dt> + <dd> + <p><!-- CL 257939 --> + The <a href="/pkg/crypto/dsa/"><code>crypto/dsa</code></a> package is now deprecated. + See <a href="https://golang.org/issue/40337">issue #40337</a>. + </p> + </dd> +</dl><!-- crypto/dsa --> + +<dl id="crypto/hmac"><dt><a href="/pkg/crypto/hmac/">crypto/hmac</a></dt> + <dd> + <p><!-- CL 261960 --> + <a href="/pkg/crypto/hmac/#New"><code>New</code></a> will now panic if + separate calls to the hash generation function fail to return new values. + Previously, the behavior was undefined and invalid outputs were sometimes + generated. + </p> + </dd> +</dl><!-- crypto/hmac --> + +<dl id="crypto/tls"><dt><a href="/pkg/crypto/tls/">crypto/tls</a></dt> + <dd> + <p><!-- CL 256897 --> + I/O operations on closing or closed TLS connections can now be detected + using the new <a href="/pkg/net/#ErrClosed"><code>net.ErrClosed</code></a> + error. A typical use would be <code>errors.Is(err, net.ErrClosed)</code>. + </p> + + <p><!-- CL 266037 --> + A default write deadline is now set in + <a href="/pkg/crypto/tls/#Conn.Close"><code>Conn.Close</code></a> + before sending the "close notify" alert, in order to prevent blocking + indefinitely. + </p> + + <p><!-- CL 246338 --> + The new <a href="/pkg/crypto/tls#Conn.HandshakeContext"><code>Conn.HandshakeContext</code></a> + method allows cancellation of an in-progress handshake. The provided + context is accessible through the new + <a href="/pkg/crypto/tls#ClientHelloInfo.Context"><code>ClientHelloInfo.Context</code></a> + and <a href="/pkg/crypto/tls#CertificateRequestInfo.Context"> + <code>CertificateRequestInfo.Context</code></a> methods. Canceling the + context after the handshake has finished has no effect. + </p> + + <p><!-- CL 239748 --> + Clients now return a handshake error if the server selects + <a href="/pkg/crypto/tls/#ConnectionState.NegotiatedProtocol"> + an ALPN protocol</a> that was not in + <a href="/pkg/crypto/tls/#Config.NextProtos"> + the list advertised by the client</a>. + </p> + + <p><!-- CL 262857 --> + Servers will now prefer other available AEAD cipher suites (such as ChaCha20Poly1305) + over AES-GCM cipher suites if either the client or server doesn't have AES hardware + support, unless both <a href="/pkg/crypto/tls/#Config.PreferServerCipherSuites"> + <code>Config.PreferServerCipherSuites</code></a> + and <a href="/pkg/crypto/tls/#Config.CipherSuites"><code>Config.CipherSuites</code></a> + are set. The client is assumed not to have AES hardware support if it does + not signal a preference for AES-GCM cipher suites. + </p> + + <p><!-- CL 246637 --> + <a href="/pkg/crypto/tls/#Config.Clone"><code>Config.Clone</code></a> now + returns nil if the receiver is nil, rather than panicking. + </p> + </dd> +</dl><!-- crypto/tls --> + +<dl id="crypto/x509"><dt><a href="/pkg/crypto/x509/">crypto/x509</a></dt> + <dd> + <p> + The <code>GODEBUG=x509ignoreCN=0</code> flag will be removed in Go 1.17. + It enables the legacy behavior of treating the <code>CommonName</code> + field on X.509 certificates as a host name when no Subject Alternative + Names are present. + </p> + + <p><!-- CL 235078 --> + <a href="/pkg/crypto/x509/#ParseCertificate"><code>ParseCertificate</code></a> and + <a href="/pkg/crypto/x509/#CreateCertificate"><code>CreateCertificate</code></a> + now enforce string encoding restrictions for the <code>DNSNames</code>, + <code>EmailAddresses</code>, and <code>URIs</code> fields. These fields + can only contain strings with characters within the ASCII range. + </p> + + <p><!-- CL 259697 --> + <a href="/pkg/crypto/x509/#CreateCertificate"><code>CreateCertificate</code></a> + now verifies the generated certificate's signature using the signer's + public key. If the signature is invalid, an error is returned, instead of + a malformed certificate. + </p> + + <p><!-- CL 233163 --> + A number of additional fields have been added to the + <a href="/pkg/crypto/x509/#CertificateRequest"><code>CertificateRequest</code></a> type. + These fields are now parsed in <a href="/pkg/crypto/x509/#ParseCertificateRequest"> + <code>ParseCertificateRequest</code></a> and marshalled in + <a href="/pkg/crypto/x509/#CreateCertificateRequest"><code>CreateCertificateRequest</code></a>. + </p> + + <p><!-- CL 257939 --> + DSA signature verification is no longer supported. Note that DSA signature + generation was never supported. + See <a href="https://golang.org/issue/40337">issue #40337</a>. + </p> + + <p><!-- CL 257257 --> + On Windows, <a href="/pkg/crypto/x509/#Certificate.Verify"><code>Certificate.Verify</code></a> + will now return all certificate chains that are built by the platform + certificate verifier, instead of just the highest ranked chain. + </p> + + <p><!-- CL 262343 --> + The new <a href="/pkg/crypto/x509/#SystemRootsError.Unwrap"><code>SystemRootsError.Unwrap</code></a> + method allows accessing the <a href="/pkg/crypto/x509/#SystemRootsError.Err"><code>Err</code></a> + field through the <a href="/pkg/errors"><code>errors</code></a> package functions. + </p> + </dd> +</dl><!-- crypto/x509 --> + +<dl id="encoding/asn1"><dt><a href="/pkg/encoding/asn1">encoding/asn1</a></dt> + <dd> + <p><!-- CL 255881 --> + <a href="/pkg/encoding/asn1/#Unmarshal"><code>Unmarshal</code></a> and + <a href="/pkg/encoding/asn1/#UnmarshalWithParams"><code>UnmarshalWithParams</code></a> + now return an error instead of panicking when the argument is not + a pointer or is nil. This change matches the behavior of other + encoding packages such as <a href="/pkg/encoding/json"><code>encoding/json</code></a>. + </p> + </dd> +</dl> + +<dl id="encoding/json"><dt><a href="/pkg/encoding/json/">encoding/json</a></dt> + <dd> + <p><!-- CL 234818 --> + The <code>json</code> struct field tags understood by + <a href="/pkg/encoding/json/#Marshal"><code>Marshal</code></a>, + <a href="/pkg/encoding/json/#Unmarshal"><code>Unmarshal</code></a>, + and related functionality now permit semicolon characters within + a JSON object name for a Go struct field. + </p> + </dd> +</dl><!-- encoding/json --> + +<dl id="encoding/xml"><dt><a href="/pkg/encoding/xml/">encoding/xml</a></dt> + <dd> + <p><!-- CL 264024 --> + The encoder has always taken care to avoid using namespace prefixes + beginning with <code>xml</code>, which are reserved by the XML + specification. + Now, following the specification more closely, that check is + case-insensitive, so that prefixes beginning + with <code>XML</code>, <code>XmL</code>, and so on are also + avoided. + </p> + </dd> +</dl><!-- encoding/xml --> + +<dl id="flag"><dt><a href="/pkg/flag/">flag</a></dt> + <dd> + <p><!-- CL 240014 --> + The new <a href="/pkg/flag/#Func"><code>Func</code></a> function + allows registering a flag implemented by calling a function, + as a lighter-weight alternative to implementing the + <a href="/pkg/flag/#Value"><code>Value</code></a> interface. + </p> + </dd> +</dl><!-- flag --> + +<dl id="io"><dt><a href="/pkg/io/">io</a></dt> + <dd> + <p><!-- CL 261577 --> + The package now defines a + <a href="/pkg/io/#ReadSeekCloser"><code>ReadSeekCloser</code></a> interface. + </p> + </dd> +</dl><!-- io --> + +<dl id="log"><dt><a href="/pkg/log/">log</a></dt> + <dd> + <p><!-- CL 264460 --> + The new <a href="/pkg/log/#Default"><code>Default</code></a> function + provides access to the default <a href="/pkg/log/#Logger"><code>Logger</code></a>. + </p> + </dd> +</dl><!-- log --> + +<dl id="log/syslog"><dt><a href="/pkg/log/syslog/">log/syslog</a></dt> + <dd> + <p><!-- CL 264297 --> + The <a href="/pkg/log/syslog/#Writer"><code>Writer</code></a> + now uses the local message format + (omitting the host name and using a shorter time stamp) + when logging to custom Unix domain sockets, + matching the format already used for the default log socket. + </p> + </dd> +</dl><!-- log/syslog --> + +<dl id="mime/multipart"><dt><a href="/pkg/mime/multipart/">mime/multipart</a></dt> + <dd> + <p><!-- CL 247477 --> + The <a href="/pkg/mime/multipart/#Reader"><code>Reader</code></a>'s + <a href="/pkg/mime/multipart/#Reader.ReadForm"><code>ReadForm</code></a> + method no longer rejects form data + when passed the maximum int64 value as a limit. + </p> + </dd> +</dl><!-- mime/multipart --> + +<dl id="net"><dt><a href="/pkg/net/">net</a></dt> + <dd> + <p><!-- CL 250357 --> + The case of I/O on a closed network connection, or I/O on a network + connection that is closed before any of the I/O completes, can now + be detected using the new <a href="/pkg/net/#ErrClosed">ErrClosed</a> error. + A typical use would be <code>errors.Is(err, net.ErrClosed)</code>. + In earlier releases the only way to reliably detect this case was to + match the string returned by the <code>Error</code> method + with <code>"use of closed network connection"</code>. + </p> + + <p><!-- CL 255898 --> + In previous Go releases the default TCP listener backlog size on Linux systems, + set by <code>/proc/sys/net/core/somaxconn</code>, was limited to a maximum of <code>65535</code>. + On Linux kernel version 4.1 and above, the maximum is now <code>4294967295</code>. + </p> + + <p><!-- CL 238629 --> + On Linux, host name lookups no longer use DNS before checking + <code>/etc/hosts</code> when <code>/etc/nsswitch.conf</code> + is missing; this is common on musl-based systems and makes + Go programs match the behavior of C programs on those systems. + </p> + </dd> +</dl><!-- net --> <dl id="net/http"><dt><a href="/pkg/net/http/">net/http</a></dt> <dd> @@ -171,9 +760,208 @@ Do not send CLs removing the interior tags from such phrases. </p> <p><!-- CL 252497 --> - The <a href="/pkg/net/http/"><code>net/http</code></a> package now rejects HTTP range requests - of the form <code>"Range": "bytes=--N"</code> where <code>"-N"</code> is a negative suffix length, for - example <code>"Range": "bytes=--2"</code>. It now replies with a <code>416 "Range Not Satisfiable"</code> response. + The <a href="/pkg/net/http/"><code>net/http</code></a> package now rejects HTTP range requests + of the form <code>"Range": "bytes=--N"</code> where <code>"-N"</code> is a negative suffix length, for + example <code>"Range": "bytes=--2"</code>. It now replies with a <code>416 "Range Not Satisfiable"</code> response. + </p> + + <p><!-- CL 256498, golang.org/issue/36990 --> + Cookies set with <a href="/pkg/net/http/#SameSiteDefaultMode"><code>SameSiteDefaultMode</code></a> + now behave according to the current spec (no attribute is set) instead of + generating a SameSite key without a value. + </p> + + <p><!-- CL 246338 --> + The <a href="/pkg/net/http/"><code>net/http</code></a> package now passes the + <a href="/pkg/net/http/#Request.Context"><code>Request</code> context</a> to + <a href="/pkg/crypto/tls#Conn.HandshakeContext"><code>tls.Conn.HandshakeContext</code></a> + when performing TLS handshakes. + </p> + + <p><!-- CL 250039 --> + The <a href="/pkg/net/http/#Client">Client</a> now sends + an explicit <code>Content-Length:</code> <code>0</code> + header in <code>PATCH</code> requests with empty bodies, + matching the existing behavior of <code>POST</code> and <code>PUT</code>. + </p> + + <p><!-- CL 249440 --> + The <a href="/pkg/net/http/#ProxyFromEnvironment">ProxyFromEnvironment</a> function + no longer returns the setting of the <code>HTTP_PROXY</code> environment + variable for <code>https://</code> URLs when <code>HTTPS_PROXY</code> is unset. </p> </dd> </dl><!-- net/http --> + +<dl id="net/http/httputil"><dt><a href="/pkg/net/http/httputil/">net/http/httputil</a></dt> + <dd> + <p><!-- CL 260637 --> + The <a href="/pkg/net/http/httputil/#ReverseProxy">ReverseProxy</a> + now flushes buffered data more aggressively when proxying + streamed responses with unknown body lengths. + </p> + </dd> +</dl><!-- net/http/httputil --> + +<dl id="net/smtp"><dt><a href="/pkg/net/smtp/">net/smtp</a></dt> + <dd> + <p><!-- CL 247257 --> + The <a href="/pkg/net/smtp/#Client">Client</a>'s + <a href="/pkg/net/smtp/#Client.Mail"><code>Mail</code></a> + method now sends the <code>SMTPUTF8</code> directive to + servers that support it, signaling that addresses are encoded in UTF-8. + </p> + </dd> +</dl><!-- net/smtp --> + +<dl id="os"><dt><a href="/pkg/os/">os</a></dt> + <dd> + <p><!-- CL 242998 --> + <a href="/pkg/os/#Process.Signal"><code>Process.Signal</code></a> now + returns <a href="/pkg/os/#ErrProcessDone"><code>ErrProcessDone</code></a> + instead of the unexported <code>errFinished</code> when the process has + already finished. + </p> + </dd> +</dl><!-- os --> + +<dl id="os/signal"><dt><a href="/pkg/os/signal/">os/signal</a></dt> + <dd> + <p><!-- CL 219640 --> + The new + <a href="/pkg/os/signal/#NotifyContext"><code>NotifyContext</code></a> + function allows creating contexts that are canceled upon arrival of + specific signals. + </p> + </dd> +</dl><!-- os/signal --> + +<dl id="path"><dt><a href="/pkg/path/">path</a></dt> + <dd> + <p><!-- CL 264397, golang.org/issues/28614 --> + The <code>Match</code> and <code>Glob</code> functions now + return an error if the unmatched part of the pattern has a + syntax error. Previously, the functions returned early on a failed + match, and thus did not report any later syntax error in the + pattern. + </p> + </dd> +</dl><!-- path --> + +<dl id="path/filepath"><dt><a href="/pkg/path/filepath/">path/filepath</a></dt> + <dd> + <p><!-- CL 264397, golang.org/issues/28614 --> + The <code>Match</code> and <code>Glob</code> functions now + return an error if the unmatched part of the pattern has a + syntax error. Previously, the functions returned early on a failed + match, and thus did not report any later syntax error in the + pattern. + </p> + </dd> +</dl><!-- path/filepath --> + +<dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt> + <dd> + <p><!-- CL 248341, golang.org/issues/40281 --> + <code>StructTag</code> now allows multiple space-separated keys + in key:value pairs, as in <code>`json xml:"field1"`</code> + (equivalent to <code>`json:"field1" xml:"field1"`</code>). + </p> + </dd> +</dl><!-- reflect --> + +<dl id="runtime/debug"><dt><a href="/pkg/runtime/debug/">runtime/debug</a></dt> + <dd> + <p><!-- CL 249677 --> + The <a href="/pkg/runtime#Error"><code>runtime.Error</code></a> values + used when <code>SetPanicOnFault</code> is enabled may now have an + <code>Addr</code> method. If that method exists, it returns the memory + address that triggered the fault. + </p> + </dd> +</dl><!-- runtime/debug --> + +<dl id="strconv"><dt><a href="/pkg/strconv/">strconv</a></dt> + <dd> + <p><!-- CL 260858 --> + <a href="/pkg/strconv/#ParseFloat"><code>ParseFloat</code></a> now uses + the <a + href="https://nigeltao.github.io/blog/2020/eisel-lemire.html">Eisel-Lemire + algorithm</a>, improving performance by up to a factor of 2. This can + also speed up decoding textual formats like <a + href="/pkg/encoding/json/"><code>encoding/json</code></a>. + </p> + </dd> +</dl><!-- strconv --> + +<dl id="syscall"><dt><a href="/pkg/syscall/">syscall</a></dt> + <dd> + <p><!-- CL 263271 --> + <a href="/pkg/syscall/?GOOS=windows#NewCallback"><code>NewCallback</code></a> + and + <a href="/pkg/syscall/?GOOS=windows#NewCallbackCDecl"><code>NewCallbackCDecl</code></a> + now correctly support callback functions with multiple + sub-<code>uintptr</code>-sized arguments in a row. This may + require changing uses of these functions to eliminate manual + padding between small arguments. + </p> + + <p><!-- CL 261917 --> + <a href="/pkg/syscall/?GOOS=windows#SysProcAttr"><code>SysProcAttr</code></a> on Windows has a new NoInheritHandles field that disables inheriting handles when creating a new process. + </p> + + <p><!-- CL 269761, golang.org/issue/42584 --> + <a href="/pkg/syscall/?GOOS=windows#DLLError"><code>DLLError</code></a> on Windows now has an Unwrap function for unwrapping its underlying error. + </p> + + <p><!-- CL 210639 --> + On Linux, + <a href="/pkg/syscall/#Setgid"><code>Setgid</code></a>, + <a href="/pkg/syscall/#Setuid"><code>Setuid</code></a>, + and related calls are now implemented. + Previously, they returned an <code>syscall.EOPNOTSUPP</code> error. + </p> + </dd> +</dl><!-- syscall --> + +<dl id="text/template"><dt><a href="/pkg/text/template/">text/template</a></dt> + <dd> + <p><!-- CL 254257, golang.org/issue/29770 --> + Newlines characters are now allowed inside action delimiters, + permitting actions to span multiple lines. + </p> + </dd> +</dl><!-- text/template --> + +<dl id="text/template/parse"><dt><a href="/pkg/text/template/parse/">text/template/parse</a></dt> + <dd> + <p><!-- CL 229398, golang.org/issue/34652 --> + A new <a href="/pkg/text/template/parse/#CommentNode"><code>CommentNode</code></a> + was added to the parse tree. The <a href="/pkg/text/template/parse/#Mode"><code>Mode</code></a> + field in the <code>parse.Tree</code> enables access to it. + </p> + </dd> +</dl><!-- text/template/parse --> + +<dl id="time/tzdata"><dt><a href="/pkg/time/tzdata/">time/tzdata</a></dt> + <dd> + <p><!-- CL 261877 --> + The slim timezone data format is now used for the timezone database in + <code>$GOROOT/lib/time/zoneinfo.zip</code> and the embedded copy in this + package. This reduces the size of the timezone database by about 350 KB. + </p> + </dd> +</dl><!-- time/tzdata --> + +<dl id="unicode"><dt><a href="/pkg/unicode/">unicode</a></dt> + <dd> + <p><!-- CL 248765 --> + The <a href="/pkg/unicode/"><code>unicode</code></a> package and associated + support throughout the system has been upgraded from Unicode 12.0.0 to + <a href="https://www.unicode.org/versions/Unicode13.0.0/">Unicode 13.0.0</a>, + which adds 5,930 new characters, including four new scripts, and 55 new emoji. + Unicode 13.0.0 also designates plane 3 (U+30000-U+3FFFF) as the tertiary + ideographic plane. + </p> + </dd> +</dl><!-- unicode --> diff --git a/doc/go1.html b/doc/go1.html index 34e305b93c..939ee24df5 100644 --- a/doc/go1.html +++ b/doc/go1.html @@ -1647,14 +1647,14 @@ c := signal.Incoming() is </p> <pre> -c := make(chan os.Signal) +c := make(chan os.Signal, 1) signal.Notify(c) // ask for all signals </pre> <p> but most code should list the specific signals it wants to handle instead: </p> <pre> -c := make(chan os.Signal) +c := make(chan os.Signal, 1) signal.Notify(c, syscall.SIGHUP, syscall.SIGQUIT) </pre> diff --git a/doc/go_spec.html b/doc/go_spec.html index 154bdbfeaf..676407f6f2 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -1,6 +1,6 @@ <!--{ "Title": "The Go Programming Language Specification", - "Subtitle": "Version of Jan 14, 2020", + "Subtitle": "Version of Oct 7, 2020", "Path": "/ref/spec" }--> @@ -3594,23 +3594,33 @@ replaced by its left operand alone. </p> <pre> +var a [1024]byte var s uint = 33 -var i = 1<<s // 1 has type int -var j int32 = 1<<s // 1 has type int32; j == 0 -var k = uint64(1<<s) // 1 has type uint64; k == 1<<33 -var m int = 1.0<<s // 1.0 has type int; m == 0 if ints are 32bits in size -var n = 1.0<<s == j // 1.0 has type int32; n == true -var o = 1<<s == 2<<s // 1 and 2 have type int; o == true if ints are 32bits in size -var p = 1<<s == 1<<33 // illegal if ints are 32bits in size: 1 has type int, but 1<<33 overflows int -var u = 1.0<<s // illegal: 1.0 has type float64, cannot shift -var u1 = 1.0<<s != 0 // illegal: 1.0 has type float64, cannot shift -var u2 = 1<<s != 1.0 // illegal: 1 has type float64, cannot shift -var v float32 = 1<<s // illegal: 1 has type float32, cannot shift -var w int64 = 1.0<<33 // 1.0<<33 is a constant shift expression -var x = a[1.0<<s] // 1.0 has type int; x == a[0] if ints are 32bits in size -var a = make([]byte, 1.0<<s) // 1.0 has type int; len(a) == 0 if ints are 32bits in size -</pre> +// The results of the following examples are given for 64-bit ints. +var i = 1<<s // 1 has type int +var j int32 = 1<<s // 1 has type int32; j == 0 +var k = uint64(1<<s) // 1 has type uint64; k == 1<<33 +var m int = 1.0<<s // 1.0 has type int; m == 1<<33 +var n = 1.0<<s == j // 1.0 has type int; n == true +var o = 1<<s == 2<<s // 1 and 2 have type int; o == false +var p = 1<<s == 1<<33 // 1 has type int; p == true +var u = 1.0<<s // illegal: 1.0 has type float64, cannot shift +var u1 = 1.0<<s != 0 // illegal: 1.0 has type float64, cannot shift +var u2 = 1<<s != 1.0 // illegal: 1 has type float64, cannot shift +var v float32 = 1<<s // illegal: 1 has type float32, cannot shift +var w int64 = 1.0<<33 // 1.0<<33 is a constant shift expression; w == 1<<33 +var x = a[1.0<<s] // panics: 1.0 has type int, but 1<<33 overflows array bounds +var b = make([]byte, 1.0<<s) // 1.0 has type int; len(b) == 1<<33 + +// The results of the following examples are given for 32-bit ints, +// which means the shifts will overflow. +var mm int = 1.0<<s // 1.0 has type int; mm == 0 +var oo = 1<<s == 2<<s // 1 and 2 have type int; oo == true +var pp = 1<<s == 1<<33 // illegal: 1 has type int, but 1<<33 overflows int +var xx = a[1.0<<s] // 1.0 has type int; xx == a[0] +var bb = make([]byte, 1.0<<s) // 1.0 has type int; len(bb) == 0 +</pre> <h4 id="Operator_precedence">Operator precedence</h4> <p> @@ -3646,7 +3656,7 @@ For instance, <code>x / y * z</code> is the same as <code>(x / y) * z</code>. x <= f() ^a >> b f() || g() -x == y+1 && <-chanPtr > 0 +x == y+1 && <-chanInt > 0 </pre> diff --git a/doc/install-source.html b/doc/install-source.html index cbf4eac70b..f0a909263c 100644 --- a/doc/install-source.html +++ b/doc/install-source.html @@ -119,41 +119,32 @@ 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 a "go" command in <code>$PATH</code>, so as long as you have Go installed in your system and configured in your <code>$PATH</code>, you are ready to build Go -from source. +from source. Or if you prefer you can set <code>$GOROOT_BOOTSTRAP</code> to the root of a Go installation to use to build the new Go toolchain; <code>$GOROOT_BOOTSTRAP/bin/go</code> should be the go command to use.</p> -<h3 id="bootstrapFromBinaryRelease">Bootstrap toolchain from binary release</h3> - <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. +There are four possible ways to obtain a bootstrap toolchain: </p> -<h3 id="bootstrapFromSource">Bootstrap toolchain from source</h3> +<ul> +<li>Download a recent binary release of Go. +<li>Cross-compile a toolchain using a system with a working Go installation. +<li>Use gccgo. +<li>Compile a toolchain from Go 1.4, the last Go release with a compiler written in C. +</ul> <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>). +These approaches are detailed below. </p> +<h3 id="bootstrapFromBinaryRelease">Bootstrap toolchain from binary release</h3> + <p> -Once the Go 1.4 source has been unpacked into your GOROOT_BOOTSTRAP directory, -you must keep this git clone instance checked out to branch -<code>release-branch.go1.4</code>. Specifically, do not attempt to reuse -this git clone in the later step named "Fetch the repository." The go1.4 -bootstrap toolchain <b>must be able</b> to properly traverse the go1.4 sources -that it assumes are present under this repository root. +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> <h3 id="bootstrapFromCrosscompiledSource">Bootstrap toolchain from cross-compiled source</h3> @@ -194,6 +185,36 @@ $ sudo update-alternatives --set go /usr/bin/go-5 $ GOROOT_BOOTSTRAP=/usr ./make.bash </pre> +<h3 id="bootstrapFromSource">Bootstrap toolchain from C source code</h3> + +<p> +To build a bootstrap toolchain from C source code, 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> +Once the Go 1.4 source has been unpacked into your GOROOT_BOOTSTRAP directory, +you must keep this git clone instance checked out to branch +<code>release-branch.go1.4</code>. Specifically, do not attempt to reuse +this git clone in the later step named "Fetch the repository." The go1.4 +bootstrap toolchain <b>must be able</b> to properly traverse the go1.4 sources +that it assumes are present under this repository root. +</p> + +<p> +Note that Go 1.4 does not run on all systems that later versions of Go do. +In particular, Go 1.4 does not support current versions of macOS. +On such systems, the bootstrap toolchain must be obtained using one of the other methods. +</p> + <h2 id="git">Install Git, if needed</h2> <p> @@ -507,8 +528,8 @@ These default to the values of <code>$GOHOSTOS</code> and <p> Choices for <code>$GOOS</code> are -<code>android</code>, <code>darwin</code> (macOS/iOS), -<code>dragonfly</code>, <code>freebsd</code>, <code>illumos</code>, <code>js</code>, +<code>android</code>, <code>darwin</code>, <code>dragonfly</code>, +<code>freebsd</code>, <code>illumos</code>, <code>ios</code>, <code>js</code>, <code>linux</code>, <code>netbsd</code>, <code>openbsd</code>, <code>plan9</code>, <code>solaris</code> and <code>windows</code>. </p> @@ -567,6 +588,9 @@ The valid combinations of <code>$GOOS</code> and <code>$GOARCH</code> are: <td></td><td><code>illumos</code></td> <td><code>amd64</code></td> </tr> <tr> +<td></td><td><code>ios</code></td> <td><code>arm64</code></td> +</tr> +<tr> <td></td><td><code>js</code></td> <td><code>wasm</code></td> </tr> <tr> @@ -663,16 +687,13 @@ For example, you should not set <code>$GOHOSTARCH</code> to <code>arm</code> on an x86 system. </p> -<li><code>$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) +<li><code>$GO386</code> (for <code>386</code> only, defaults to <code>sse2</code>) <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. +This variable controls how gc implements 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> + <li><code>GO386=softfloat</code>: use software 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 but only available on Pentium 4/Opteron/Athlon 64 or later.</li> </ul> </li> |