OpenBSD/arm64 reports itself as arm64 from `uname -m` - this currently
matches as gohostarch=arm, rather than gohostarch=arm64. Correct this
by matching on both aarch64 and arm64 (the alternative would be to use
`uname -p`, however that's likely to cause upset elsewhere).

Updates #31656

Change-Id: I7b2da93495d808e704caf032b3fadc984077769e
Reviewed-on: https://go-review.googlesource.com/c/go/+/173598Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The changes in Unicode 11 exposes a bug in maketables.go.
We update the Unicode 10 tables using a new generator
to minimize the changes upgrading to Unicode 11.

This change switches over the generation from core to that in
x/text. To properly update the tables one needs to run the generate
in x/text anyway, so this makes that official.

The RangeTable generator in x/text also generates slightly compacter
tables.

Updates golang/go#27945

See CL 154443

Change-Id: I6c59e082d5b8cd9e9332a32d8971061228581d66
Reviewed-on: https://go-review.googlesource.com/c/go/+/169617
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Using commas makes it possible to put multiple tags into GOFLAGS.
The space-separated form is still recognized and will be maintained.

Alleviates #26849 somewhat.
Fixes #18800 (again).

Change-Id: I6f4cf28ea31e53e21ccbdad6ef1a0aee63b007d7
Reviewed-on: https://go-review.googlesource.com/c/go/+/173438
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>

"go build -trimpath" trims the recorded file paths in the
resulting packages and executables to avoid recording
the names of any local directories. Instead, the files appear
to be stored in directories named either "go/src/..." (for the
standard library) or named after the module or package
in which the files appear.

Fixes #16860.

Change-Id: I433afeeb1fdeea641286b21693fee5e0a66d607e
Reviewed-on: https://go-review.googlesource.com/c/go/+/173345
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

The script test requires a manual update on each new
Unicode release, which interupts the automated flow.
The test is removed in favor of one that fits within the
automated scripts.
See https://go-review.googlesource.com/c/text/+/169638.

Updates golang/go#27945

Change-Id: I9c9f1e2a77f7baef17040ea09eec28d7cf55b5e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/169619Reviewed-by: Russ Cox <rsc@golang.org>

This CL affects the low-level -trimpath flag provided
by both cmd/asm and cmd/compile. Previously, the flag
took the name of a single directory that would be trimmed
from recorded paths in the resulting object file.
This CL makes the flag take a semicolon-separated list of paths.
Further, each path can now end in an optional "=>replacement"
to specify what to replace that leading path prefix with,
instead of only dropping it.

A followup CL will add a mode to cmd/go that uses this
richer -trimpath to build binaries that do not contain any
local path names.

For #16860.

Change-Id: I246811750f37607c7f7a8fbecd56c5475ebe1ea5
Reviewed-on: https://go-review.googlesource.com/c/go/+/173344
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

This avoids bounds checks in the calling code.
The nominal increased size of the array in the binary
is compensated for by the decreased size of the functions that call it.

The benchmark changes are a bit scattered, but overall positive.

name                                 old time/op  new time/op  delta
RuneCountTenASCIIChars-8             8.86ns ± 4%  7.93ns ± 5%  -10.45%  (p=0.000 n=45+49)
RuneCountTenJapaneseChars-8          38.2ns ± 2%  37.2ns ± 1%   -2.63%  (p=0.000 n=44+41)
RuneCountInStringTenASCIIChars-8     7.82ns ± 2%  8.70ns ± 2%  +11.19%  (p=0.000 n=43+43)
RuneCountInStringTenJapaneseChars-8  39.3ns ± 9%  40.0ns ± 5%   +1.59%  (p=0.043 n=50+50)
ValidTenASCIIChars-8                 8.68ns ± 5%  8.74ns ± 5%     ~     (p=0.070 n=50+48)
ValidTenJapaneseChars-8              34.1ns ± 5%  36.8ns ± 4%   +8.09%  (p=0.000 n=45+50)
ValidStringTenASCIIChars-8           9.76ns ± 7%  8.33ns ± 3%  -14.59%  (p=0.000 n=48+47)
ValidStringTenJapaneseChars-8        37.7ns ± 8%  36.5ns ± 5%   -3.12%  (p=0.011 n=50+47)
EncodeASCIIRune-8                    2.60ns ± 1%  2.59ns ± 2%   -0.24%  (p=0.018 n=43+36)
EncodeJapaneseRune-8                 3.75ns ± 2%  4.56ns ± 6%  +21.71%  (p=0.000 n=41+50)
DecodeASCIIRune-8                    2.59ns ± 2%  2.59ns ± 2%     ~     (p=0.350 n=44+41)
DecodeJapaneseRune-8                 4.29ns ± 2%  4.31ns ± 2%   +0.61%  (p=0.001 n=48+39)
FullASCIIRune-8                      0.87ns ± 6%  0.29ns ± 5%  -67.31%  (p=0.000 n=49+43)
FullJapaneseRune-8                   0.65ns ± 6%  0.65ns ± 4%     ~     (p=0.375 n=50+49)
[Geo mean]                           7.02ns       6.51ns        -7.19%


Change-Id: I8d5d69c8d33ce2bff94785fba39a2203f9315cb0
Reviewed-on: https://go-review.googlesource.com/c/go/+/173537
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The compiler has advanced enough that it is cheaper
to convert to strings than to go through the assembly
trampolines to call runtime.memequal.

Simplify Equal accordingly, and cull dead code from bytealg.

While we're here, simplify Equal's documentation.

Fixes #31587

Change-Id: Ie721d33f9a6cbd86b1d873398b20e7882c2c63e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/173323
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

cmd/go/internal/modcmd: assign module's path and version to fileJSON when modFile's module statement exists

Fixes panic on nil pointer dereference error when assigning module's path and version pair to fileJSON.

Fixes #31623

Change-Id: I3f61122ba0676a1270d3ad98900af8c8e9c90935
Reviewed-on: https://go-review.googlesource.com/c/go/+/173397
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Build result string via string.Builder to avoid allocation.
As side effect some performance boots.

name                 old time/op    new time/op    delta
QueryUnescape/#00-4     114ns ± 0%      98ns ± 1%  -13.89%  (p=0.000 n=4+5)
QueryUnescape/#01-4     401ns ± 2%     383ns ± 1%   -4.54%  (p=0.008 n=5+5)
QueryUnescape/#02-4     300ns ± 2%     274ns ± 2%   -8.66%  (p=0.008 n=5+5)
QueryUnescape/#03-4     564ns ± 2%     542ns ± 2%   -4.04%  (p=0.008 n=5+5)
QueryUnescape/#04-4    3.27µs ± 2%    3.34µs ± 8%     ~     (p=0.690 n=5+5)
PathUnescape/#00-4      112ns ± 2%      99ns ± 3%  -11.25%  (p=0.008 n=5+5)
PathUnescape/#01-4      392ns ± 2%     374ns ± 6%     ~     (p=0.063 n=5+5)
PathUnescape/#02-4      296ns ± 2%     274ns ± 2%   -7.43%  (p=0.008 n=5+5)
PathUnescape/#03-4      556ns ± 2%     537ns ± 1%   -3.45%  (p=0.008 n=5+5)
PathUnescape/#04-4     2.99µs ± 1%    3.00µs ± 1%     ~     (p=0.690 n=5+5)

name                 old allocs/op  new allocs/op  delta
QueryUnescape/#00-4      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
QueryUnescape/#01-4      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
QueryUnescape/#02-4      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
QueryUnescape/#03-4      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
QueryUnescape/#04-4      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
PathUnescape/#00-4       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
PathUnescape/#01-4       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
PathUnescape/#02-4       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
PathUnescape/#03-4       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)
PathUnescape/#04-4       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.008 n=5+5)

Change-Id: I7cba5eb53bebef7b1fdd44598eed47241ce83167
Reviewed-on: https://go-review.googlesource.com/c/go/+/166463Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #31638.

Change-Id: I748f64b48b75241a9db31c9f37555379a841677a
Reviewed-on: https://go-review.googlesource.com/c/go/+/173443
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #31597

Change-Id: I0db1f6f457632c49f9ecfa9d85b99b4cf7d91325
Reviewed-on: https://go-review.googlesource.com/c/go/+/173362
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

This reverts CL 168038 (git 68819fb6)

Reason for revert: Doesn't work on 32 bit archs.

Change-Id: Idec9098060dc65bc2f774c5383f0477f8eb63a3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/173442Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The cmd/go/internal/web package was forked in order to support direct
HTTPS fetches from widely-used hosting providers,¹ but direct fetches
were subsequently dropped in CL 107657. The forked web2 package, with
its GitHub-specific diagnostics and .netrc support, remained in use
for module proxy support, but was not used for the initial '?go-get=1'
path resolution, so the .netrc file was only used to fetch from
already-resolved module protocol servers.

This CL moves the .netrc support into its own (new) package,
cmd/go/internal/auth, and consolidates the web and web2 packages back
into just web. As a result, fetches via the web package now support
.netrc, and fetches that previously used web2 now enforce the same
security policies as web (such as prohibiting HTTPS-to-HTTP
redirects).

¹https://github.com/golang/vgo/commit/63138cb6ceed7d6d4e51a8cbd568c64bd3e2b132

Fixes #29591
Fixes #29888
Fixes #30610
Updates #26232

Change-Id: Ia3a13526e443679cf14a72a1f3db96f336ce5e73
Reviewed-on: https://go-review.googlesource.com/c/go/+/170879
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

This was originally

Revert "cmd/link: fix up debug_range for dsymutil (revert CL 72371)"

which has the effect of no longer using Base Address Selection
Entries in DWARF.  However, the build-time costs of that are
about 2%, so instead the hacky fixup that generated technically
incorrect DWARF was removed from the linker, and the choice
is instead made in the compiler, dependent on platform, but
also under control of a flag so that we can report this bug
against LLDB/dsymutil/dwarfdump (really, the LLVM dwarf
libraries).

This however does not solve #31188; debugging still fails,
but dwarfdump no longer complains.  There are at least two
LLDB bugs involved, and this change will at allow us
to report them without them being rejected because our
now-obsolete workaround for the first bug creates
not-quite-DWARF.

Updates #31188.

Change-Id: I5300c51ad202147bab7333329ebe961623d2b47d
Reviewed-on: https://go-review.googlesource.com/c/go/+/170638
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>

For powers of two (c=1<<k), the divisibility check x%c == 0 can be made
just by checking the trailing zeroes via a mask x&(c-1)==0 even for signed
integers.  This avoids division fixups when just divisibility check is needed.

To apply this rule the generic divisibility rule for  A%B = A-(A/B*B) is disabled
on the "opt" pass, but this does not affect generated code as this rule is applied
later.

The speed up on amd64 due to elimination of unneccessary fixup code is ~55%:

name                     old time/op  new time/op  delta
DivconstI64-4            2.08ns ± 0%  2.07ns ± 0%     ~     (p=0.079 n=5+5)
DivisiblePow2constI64-4  1.78ns ± 1%  0.81ns ± 1%  -54.55%  (p=0.008 n=5+5)
DivconstU64-4            2.08ns ± 0%  2.08ns ± 0%     ~     (p=1.000 n=5+5)
DivconstI32-4            1.53ns ± 0%  1.53ns ± 0%     ~     (all equal)
DivisiblePow2constI32-4  1.79ns ± 1%  0.81ns ± 4%  -54.75%  (p=0.008 n=5+5)
DivconstU32-4            1.78ns ± 1%  1.78ns ± 1%     ~     (p=1.000 n=5+5)
DivconstI16-4            1.54ns ± 2%  1.53ns ± 0%     ~     (p=0.333 n=5+4)
DivisiblePow2constI16-4  1.78ns ± 0%  0.79ns ± 1%  -55.39%  (p=0.000 n=4+5)
DivconstU16-4            1.00ns ± 5%  0.99ns ± 1%     ~     (p=0.730 n=5+5)
DivconstI8-4             1.54ns ± 0%  1.53ns ± 0%     ~     (p=0.714 n=4+5)
DivisiblePow2constI8-4   1.78ns ± 0%  0.80ns ± 0%  -55.06%  (p=0.000 n=5+4)
DivconstU8-4             0.93ns ± 1%  0.95ns ± 1%   +1.72%  (p=0.024 n=5+5)

A follow-up CL will address the general case of x%c == 0 for signed integers.

Updates #15806

Change-Id: I0d284863774b1bc8c4ce87443bbaec6103e14ef4
Reviewed-on: https://go-review.googlesource.com/c/go/+/168038Reviewed-by: Keith Randall <khr@golang.org>

This is one small step to force people to not depend on the order of
initialization of packages which are not explicitly ordered by import
directives. Similar to randomizing map iteration order, this makes
sure people aren't depending on the behavior of the current release,
so that we can change the order in future releases without breaking
everyone.

Maybe one day we can randomize always, but for now we do it just in
race mode. (We would need to measure the impact on startup time before
we enabled it always.)

RELNOTE=yes

Change-Id: I99026394796125974c5f2c3660a88becb92c9df3
Reviewed-on: https://go-review.googlesource.com/c/go/+/170318
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

In 31618, we end up comparing the is-stmt-ness of positions
to repurpose real instructions as inline marks. If the is-stmt-ness
doesn't match, we end up not being able to remove the inline mark.

Always use statement-full positions to do the matching, so we
always find a match if there is one.

Also always use positions that are statements for inline marks.

Fixes #31618

Change-Id: Idaf39bdb32fa45238d5cd52973cadf4504f947d5
Reviewed-on: https://go-review.googlesource.com/c/go/+/173324
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>

Noticed while preparing a CL for Go 1.14 to remove esc.go.

Change-Id: Ic12be33f5b16c8424d85f373fa450247be086078
Reviewed-on: https://go-review.googlesource.com/c/go/+/173298
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Where assembly functions are just jumps to the Go implementation
put them into a stubs_<arch>.s file. This reduces the number of
files considerably and makes it easier to see what is really
implemented in assembly.

I've also run the stubs files through asmfmt to format them in
a more consistent way.

Eventually we should replace these 'stub' assembly files with
a pure Go implementation now that we have mid-stack inlining
(see #31362).

Change-Id: If5b2022dcc23e1299f1b7ba79884f1b1263d0f7f
Reviewed-on: https://go-review.googlesource.com/c/go/+/173398
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I1380229c250a6100dc7e0bcf59be8df425a3efac
Reviewed-on: https://go-review.googlesource.com/c/go/+/173399Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The top right menu in Gerrit is now a gear icon, and the link
has a slightly different title.

Change-Id: I3f5d194f31ad09a99416a45db392aa4b5c7d98ff
Reviewed-on: https://go-review.googlesource.com/c/go/+/173400Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The gccgo toolchain uses the archiver specified by the AR environment
variable, or `ar` by default. Teach the build ID to take the value of
this environment variable into account, since different archivers can
produce different results.

Fix #30046.

Change-Id: Ia6821258d54eecedb9026afc38a515cd564c45cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/160897
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Make explicit that Compact does HTML escaping.

Fixes #30357.

Change-Id: I4648f8f3e907d659db977d07253f716df6e07d7b
Reviewed-on: https://go-review.googlesource.com/c/go/+/173417
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

It is easier to ensure that the symbol is always present
if we move it to package runtime. Avoids init-time work.
Also moves it next to buildVersion, the other similar symbol.

Setting up for "go version <binary>".

For #31624.

Change-Id: I943724469ce6992153e701257eb6f12da88c8e4e
Reviewed-on: https://go-review.googlesource.com/c/go/+/173341
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This adds the ability to determine if a lookup error was
due to a non-existent hostname. Previously users needed
to do string matching on the DNSError.Err value.

Fixes #28635

Change-Id: If4bd3ad32cbc2db5614f2c6b72e0a9161d813efa
Reviewed-on: https://go-review.googlesource.com/c/go/+/168597
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

In the common case, structs have a handful of fields and most inputs
match struct field names exactly.

The previous code would do a linear search over the fields, stopping at
the first exact match, and otherwise using the first case insensitive
match.

This is unfortunate, because it means that for the common case, we'd do
a linear search with bytes.Equal. Even for structs with only two or
three fields, that is pretty wasteful.

Worse even, up until the exact match was found via the linear search,
all previous fields would run their equalFold functions, which aren't
cheap even in the simple case.

Instead, cache a map along with the field list that indexes the fields
by their name. This way, a case sensitive field search doesn't involve a
linear search, nor does it involve any equalFold func calls.

This patch should also slightly speed up cases where there's a case
insensitive match but not a case sensitive one, as then we'd avoid
calling bytes.Equal on all the fields. Though that's not a common case,
and there are no benchmarks for it.

name           old time/op    new time/op    delta
CodeDecoder-8    11.0ms ± 0%    10.6ms ± 1%  -4.42%  (p=0.000 n=9+10)

name           old speed      new speed      delta
CodeDecoder-8   176MB/s ± 0%   184MB/s ± 1%  +4.62%  (p=0.000 n=9+10)

name           old alloc/op   new alloc/op   delta
CodeDecoder-8    2.28MB ± 0%    2.28MB ± 0%    ~     (p=0.725 n=10+10)

name           old allocs/op  new allocs/op  delta
CodeDecoder-8     76.9k ± 0%     76.9k ± 0%    ~     (all equal)

Updates #28923.

Change-Id: I9929c1f06c76505e5b96914199315dbdaae5dc76
Reviewed-on: https://go-review.googlesource.com/c/go/+/172918
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Combine the OBYTES2STR and ORUNES2STR cases, as they are identical.

Clean up the construction, commenting, and spacing of the other cases,
and make them all match.

Passes toolstash-check.

Change-Id: I1be8a528927caeb15e49cb12ca0f11c0827dadd9
Reviewed-on: https://go-review.googlesource.com/c/go/+/173322
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Setting environment variables for go command configuration
is too difficult and system-specific. This CL adds go env -w,
to change the default settings more easily, in a portable way.
It also adds go env -u, to unset those changes.

See https://golang.org/design/30411-env for details.

Fixes #30411.

Change-Id: I36e83f55b666459f8f7f482432a4a6ee015da71d
Reviewed-on: https://go-review.googlesource.com/c/go/+/171137
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Passes toolstash-check.

Change-Id: I02efba7bab3ea49d87c8472bbb99116565bf8423
Reviewed-on: https://go-review.googlesource.com/c/go/+/173321Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

No meaningful change, but allows the followup CL to pass
toolstash-check.

Change-Id: I1d852c97838be3f84cf795bc9daec9b15c705956
Reviewed-on: https://go-review.googlesource.com/c/go/+/173320
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Explicitly warn callers that no URL encoding is performed and
that they might need to do it.

Fixes #31577

Change-Id: I52dc3fd2798ba8c3652d4a967b1c5c48eb69f43b
Reviewed-on: https://go-review.googlesource.com/c/go/+/173319Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

See suggestion 2 of #31543 by thepudds.

We may want to expand 'go help mod init' in the future to document what
the module path should look like.

Change-Id: Ia559fa96fda871e011d53f42a803175abc512202
Reviewed-on: https://go-review.googlesource.com/c/go/+/173318
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

go:generate commands passed no arguments are currently subject
to premature variable substitution due to mistakenly assuming append
guarantees a copy.  The change fixes this by forcing a slice copy at
each invocation of a command.

The previous code assumed that append would always generate a
copy of its inputs. However, append wouldn't create a copy if there was
no need to increase capacity and it would just return the original
input slice. This resulted in premature variable substitutions in
the "master word list" of generate commands, thus yielding incorrect
results across multiple invocations of the same command when the
body contained substitutions e.g. environment variables, moreover
these can change during the lifetime of go:generate processing a
file.

Note that this behavior would not manifest itself if any arguments were
passed to the command, because append would make a copy of the slice
as it needed to increase its capacity.   The "hacky" work-around was to
always pass at least one argument to any command, even if the
command ignores it.  e.g.,
       //go:generate MyNoArgsCmd ' '

This CL fixes that issue and removes the need for the hack mentioned
above.

Fixes #31608

Change-Id: I782ac2234bd7035a37f61c101ee4aee38ed8d29f
GitHub-Last-Rev: 796d3430191f183c123c450a60b4a7987cc85e20
GitHub-Pull-Request: golang/go#31527
Reviewed-on: https://go-review.googlesource.com/c/go/+/172580
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Stack object generation code was always using the local package name
for its symbol. Normally that doesn't matter, as we usually only
compile functions in the local package. But for wrappers, the compiler
generates functions which live in other packages. When there are two
other packages with identical functions to wrap, the same name appears
twice, and the compiler goes boom.

Fixes #31252

Change-Id: I7026eebabe562cb159b8b6046cf656afd336ba25
Reviewed-on: https://go-review.googlesource.com/c/go/+/171464
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

It will use the full names that appear in netbsd's /usr/include/sys/syscall.h names.
This adds some compat-goo (sys_sigprocmask->SYS_sigprocmask14), which might not be pretty, but the information about whether the compat version is used is probably important, as Go will keep using interfaces even after they are considered compatibility, which has caused problems in the past.
also, the same names appear in ktrace (with the numbers).

Change-Id: Idc1bb254ee33757a39ba224d91e8fbb0331e2149
GitHub-Last-Rev: b915e8f8a323cdc2d03119c3cf18e35d08c63d18
GitHub-Pull-Request: golang/go#31594
Reviewed-on: https://go-review.googlesource.com/c/go/+/173158Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Some of the comments were unclear or outdated.

Change-Id: I02e01bf60def0074c1fa760e94aa992e9e4969b9
Reviewed-on: https://go-review.googlesource.com/c/go/+/172987
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

We can work out how many bytes can be unquoted trivially in
rescanLiteral, which already iterates over a string's bytes.

Removing the extra loop in unquoteBytes simplifies the function and
speeds it up, especially when decoding simple strings, which are common.

While at it, we can remove unnecessary checks like len(s)<2 and
s[0]=='"'. Add a comment explaining why.

name           old time/op    new time/op    delta
CodeDecoder-8    11.2ms ± 0%    11.1ms ± 1%  -1.63%  (p=0.000 n=9+10)

name           old speed      new speed      delta
CodeDecoder-8   173MB/s ± 0%   175MB/s ± 1%  +1.66%  (p=0.000 n=9+10)

Updates #28923.

Change-Id: I2436a3a7f8148a2f7a6a4cdbd7dec6b32ef5e20c
Reviewed-on: https://go-review.googlesource.com/c/go/+/151157
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Unroll the cycle 4 times to reduce load overhead.

Benchmarks:
name                old time/op    new time/op    delta
MulAddVWW/1-8         15.9ns ± 0%    11.9ns ± 0%  -24.92%  (p=0.000 n=8+8)
MulAddVWW/2-8         16.1ns ± 0%    13.9ns ± 1%  -13.82%  (p=0.000 n=8+8)
MulAddVWW/3-8         18.9ns ± 0%    17.3ns ± 0%   -8.47%  (p=0.000 n=8+8)
MulAddVWW/4-8         21.7ns ± 0%    19.5ns ± 0%  -10.14%  (p=0.000 n=8+8)
MulAddVWW/5-8         25.1ns ± 0%    22.5ns ± 0%  -10.27%  (p=0.000 n=8+8)
MulAddVWW/10-8        41.6ns ± 0%    40.0ns ± 0%   -3.79%  (p=0.000 n=8+8)
MulAddVWW/100-8        368ns ± 0%     363ns ± 0%   -1.36%  (p=0.000 n=8+8)
MulAddVWW/1000-8      3.52µs ± 0%    3.52µs ± 0%   -0.14%  (p=0.000 n=8+8)
MulAddVWW/10000-8     35.1µs ± 0%    35.1µs ± 0%   -0.01%  (p=0.000 n=7+6)
MulAddVWW/100000-8     351µs ± 0%     351µs ± 0%   +0.15%  (p=0.038 n=8+8)

Change-Id: I052a4db286ac6e4f3293289c7e9a82027da0405e
Reviewed-on: https://go-review.googlesource.com/c/go/+/155780
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

This CL instrinsifies Sub64 with arm64 instruction sequence NEGS, SBCS,
NGC and NEG, and optimzes the case of borrowing chains.

Benchmarks:
name              old time/op       new time/op       delta
Sub-64            2.500000ns +- 0%  2.048000ns +- 1%  -18.08%  (p=0.000 n=10+10)
Sub32-64          2.500000ns +- 0%  2.500000ns +- 0%     ~     (all equal)
Sub64-64          2.500000ns +- 0%  2.080000ns +- 0%  -16.80%  (p=0.000 n=10+7)
Sub64multiple-64  7.090000ns +- 0%  2.090000ns +- 0%  -70.52%  (p=0.000 n=10+10)

Change-Id: I3d2664e009a9635e13b55d2c4567c7b34c2c0655
Reviewed-on: https://go-review.googlesource.com/c/go/+/159018Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>