On amd64 ReverseBytes16 is lowered to a rotate instruction. However arm64 doesn't
have 16-bit rotate instruction, but has a REV16W instruction which can be used
for ReverseBytes16. This CL adds a rule to turn the patterns like (x<<8) | (x>>8)
(the type of x is uint16, and "|" can also be "^" or "+") to a REV16W instruction.

Code:
func reverseBytes16(i uint16) uint16 { return bits.ReverseBytes16(i) }

Before:
        0x0004 00004 (test.go:6)        MOVHU   "".i(FP), R0
        0x0008 00008 ($GOROOT/src/math/bits/bits.go:262)        UBFX    $8, R0, $8, R1
        0x000c 00012 ($GOROOT/src/math/bits/bits.go:262)        ORR     R0<<8, R1, R0
        0x0010 00016 (test.go:6)        MOVH    R0, "".~r1+8(FP)
        0x0014 00020 (test.go:6)        RET     (R30)

After:
        0x0000 00000 (test.go:6)        MOVHU   "".i(FP), R0
        0x0004 00004 (test.go:6)        REV16W  R0, R0
        0x0008 00008 (test.go:6)        MOVH    R0, "".~r1+8(FP)
        0x000c 00012 (test.go:6)        RET     (R30)

Benchmarks:
name                old time/op       new time/op       delta
ReverseBytes-224    1.000000ns +- 0%  1.000000ns +- 0%     ~     (all equal)
ReverseBytes16-224  1.500000ns +- 0%  1.000000ns +- 0%  -33.33%  (p=0.000 n=9+10)
ReverseBytes32-224  1.000000ns +- 0%  1.000000ns +- 0%     ~     (all equal)
ReverseBytes64-224  1.000000ns +- 0%  1.000000ns +- 0%     ~     (all equal)

Change-Id: I87cd41b2d8e549bf39c601f185d5775bd42d739c
Reviewed-on: https://go-review.googlesource.com/c/157757Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Currently, runtime.KeepAlive applied on a stack object doesn't
actually keeps the stack object alive, and the heap object
referenced from it could be collected. This is because the
address of the stack object is rematerializeable, and we just
ignored KeepAlive on rematerializeable values. This CL fixes it.

Fixes #30476.

Change-Id: Ic1f75ee54ed94ea79bd46a8ddcd9e81d01556d1d
Reviewed-on: https://go-review.googlesource.com/c/164537
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Change-Id: If700a150492181f68e23e90ef829ff9eaf7ca7b5
Reviewed-on: https://go-review.googlesource.com/c/161737
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

EvalSymlinks is using GetFinalPathNameByHandle to handle symlinks with
unusual targets like \??\Volume{ABCD}\. But since CL 164201, os.Readlink
handles path like that too.

So remove all that extra code that EvalSymlinks calls when os.Readlink
fails - it is not needed any more.

Now that windows EvalSymlinks implementation is similar to unix
implementation, we can remove all slashAfterFilePathError related code
too. So do that.

This also makes TestIssue29372 pass even when TMP directory refers to
symlinks with target like \??\Volume{ABCD}\. So remove TestIssue29372
code that helped it pass on windows-arm. TestIssue29372 should pass as
is now.

Fixes #29746

Change-Id: I568d142c89d3297bff8513069bceaa6be51fe7e4
Reviewed-on: https://go-review.googlesource.com/c/164202
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

windows-arm TMP directory live inside such link (see
https://github.com/golang/go/issues/29746#issuecomment-456526811 for
details), so symlinks like that will be common at least on windows-arm.

This CL builds on current syscall.Readlink implementation. Main
difference between the two is how new code handles symlink targets,
like \??\Volume{ABCD}\.

New implementation uses Windows CreateFile API with
FILE_FLAG_OPEN_REPARSE_POINT flag to get \??\Volume{ABCD}\ file handle.
And then it uses Windows GetFinalPathNameByHandle with VOLUME_NAME_DOS
flag to convert that handle into standard Windows path.
FILE_FLAG_OPEN_REPARSE_POINT flag ensures that symlink is not followed
when CreateFile opens the file.

Fixes #30463

Change-Id: I33b18227ce36144caed694169ef2e429fd995fb4
Reviewed-on: https://go-review.googlesource.com/c/164201
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Add an environment variable to make.bash to allow setting the default
dynamic linker/loader. This fixes alpine builds to use
/lib/ld-musl-x86_64.so.1:

  $ readelf -l ../bin/go | grep 'interpreter:' | sed -e 's/^.*interpreter: \(.*\)[]]/\1/'
  /lib/ld-musl-x86_64.so.1

Also re-enable the internal linker tests that were previously disabled
for alpine (CL 41759, CL 41678).

Fixes #18243
Updates #19938

This resurrects CL 50070 authored by Jessie Frazelle.

Change-Id: I132b5282045a3d60c8568e3b002a7f075eac2d93
Reviewed-on: https://go-review.googlesource.com/c/163977
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

(A stripped down version of) $GOROOT is uploaded to the device
before running standar library tests, including many (all?)
testdata directories.

Use the --sync flag when pushing testdata directories to the device
in case it is already present.

Change-Id: If8104f9d15838c1be3623adcf831a7188303c376
Reviewed-on: https://go-review.googlesource.com/c/164338Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

If an ELF file has no section header table (shoff = 0), shnum must be
zero as well according to elf(5).

So far, when only shnum was zero but shoff was non-zero (i.e. in an
invalid ELF file) shstrndx wasn't properly checked and could result in
an 'index out of range' later on.

Fixes #10996

Change-Id: Ic248d2d77099b0036458e2a844b086a5f463c844
Reviewed-on: https://go-review.googlesource.com/c/162857
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Should fix Android builders on Darwin hosts.

Change-Id: I1554849bdf2ad2440529af7f93566fa6f11d5407
Reviewed-on: https://go-review.googlesource.com/c/164697
Run-TryBot: Elias Naur <mail@eliasnaur.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This reverts commit d96b7fbf.

Reason for revert: broke noopt and longtest builders.

Change-Id: Ifaec64d817c4336cb255a2e9db00526b7bc5606a
Reviewed-on: https://go-review.googlesource.com/c/164757
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

If GOCACHE is set but is not an absolute path, we cannot build.
And GOCACHE=off also returns the error message "build cache is
disabled by GOCACHE=off".

Fixes #30447

Change-Id: I24f64bc886599ca0acd757acada4714aebe4d3ae
Reviewed-on: https://go-review.googlesource.com/c/164200
Run-TryBot: Baokun Lee <nototon@gmail.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

FlagDataAddr is a vestige from git commit 0cafb9ea (2008;
no Gerrit CL number).

It was never used but unfortunately setting it would
cause a spurious warning:

  warning: -D<value> is ignored because of -R0x1000

yet if -R was unset e.g. -R=0, the linker would crash
with a divide by zero runtime panic.

Fixes #28921

Change-Id: Ia910399bc269337a9a860f3a26cd48fae6e62724
Reviewed-on: https://go-review.googlesource.com/c/151021Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

CL 163726 added workarounds to keep the iOS builders happy in
a symlinked temporary dir.

The workarounds also made the tests more realistic and improved
performance. Keep them but also handle symlinks better in the
exec wrapper.

Change-Id: Iaa2c03a1a3fb3aa5aaf62d79d52b63d5d8f11db5
Reviewed-on: https://go-review.googlesource.com/c/164698Reviewed-by: Bryan C. Mills <bcmills@google.com>

This CL moves order.go's copyRet logic for rewriting f(g()) into t1,
t2, ... = g(); f(t1, t2, ...) earlier into typecheck. This allows the
rest of the compiler to stop worrying about multi-value functions
appearing outside of OAS2FUNC nodes.

This changes compiler behavior in a few observable ways:

1. Typechecking error messages for builtin functions now use general
case error messages rather than unnecessarily differing ones.

2. Because f(g()) is rewritten before inlining, saved inline bodies
now see the rewritten form too. This could be addressed, but doesn't
seem worthwhile.

3. Most notably, this simplifies escape analysis and fixes a memory
corruption issue in esc.go. See #29197 for details.

Fixes #15992.
Fixes #29197.

Change-Id: I86a70668301efeec8fbd11fe2d242e359a3ad0af
Reviewed-on: https://go-review.googlesource.com/c/153841Reviewed-by: Robert Griesemer <gri@golang.org>

Previously, the result of sorting a map[interface{}] containing
multiple concrete types was non-deterministic. To ensure consistent
results, sort first by type name, then by concrete value.

Fixes #30398

Change-Id: I10fd4b6a74eefbc87136853af6b2e689bc76ae9d
GitHub-Last-Rev: 1b07f0c275716e1b2834f74f9c67f897bae82882
GitHub-Pull-Request: golang/go#30406
Reviewed-on: https://go-review.googlesource.com/c/163745Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

isGoConst could spuriously return true for variables that shadow a
constant declaration with the same name.

Because even named constants are always represented by OLITERAL nodes,
the easy fix is to just ignore ONAME nodes in isGoConst. We can
similarly ignore ONONAME nodes.

Confirmed that k8s.io/kubernetes/test/e2e/storage builds again with
this fix.

Fixes #30430.

Change-Id: I899400d749982d341dc248a7cd5a18277c2795ec
Reviewed-on: https://go-review.googlesource.com/c/164319
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: I91378d5d5ecc1fc6741127a3924c631904da736b
Reviewed-on: https://go-review.googlesource.com/c/164199
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

When formatting an error with a non-string formatting verb such as %d,
use the default formatting behavior rather than treating this as a bad
verb.

For example, this should print 42, not %!d(main.E=42):

  var E int
  func (E) Error() string { return "error" }
  fmt.Printf("%d", E(42))

Fixes #30472

Change-Id: I62fd309c8ee9839a69052b0ec7f1808449dcee8e
Reviewed-on: https://go-review.googlesource.com/c/164557Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

On wasm every integer is stored with 64 bits. We can do zero
extension by simply zeroing the upper bits.

Change-Id: I02c54a38b3b2b7654fff96055edab1b92d48ff32
Reviewed-on: https://go-review.googlesource.com/c/164461
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

This CL changes the internal/cpu API to more closely match the
public version in x/sys/cpu (added in CL 163003). This will make it
easier to update the dependencies of vendored code. The most prominent
renaming is from VE1 to VXE for the vector-enhancements facility 1.
VXE is the mnemonic used for this facility in the HWCAP vector.

Change-Id: I922d6c8bb287900a4bd7af70567e22eac567b5c1
Reviewed-on: https://go-review.googlesource.com/c/164437Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This pulls in CL 164497.

Fixes #24771

Change-Id: I88f2062e2c42363591dcb9e592a7a8381268ddeb
Reviewed-on: https://go-review.googlesource.com/c/164460Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

netbsd-arm needs the same override to the alignment function as
openbsd-arm. This fixes the TestPassFD failure.

Update golang/go#24771

Change-Id: Ib124fc776f6e2e3b3932784365c2bd3944523a52
Reviewed-on: https://go-review.googlesource.com/c/164458
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The template is over a hundred lines and full of pipelines, and
text/template isn't optimised to parse quickly, so it's no wonder that
delaying the parsing to the first template use makes 'go env' much
faster.

Like in the previous patches to get rid of global regexp.MustCompile
vars, use the newly introduced lazytemplate package. Close to two full
milliseconds are shaved off of 'go env' runs.

name         old time/op    new time/op    delta
ExecGoEnv-8    4.27ms ± 0%    2.63ms ± 1%  -38.43%  (p=0.002 n=6+6)

Updates #29382.

Change-Id: I4e2569e51ddf2afe1b46eb1a9e9e5845f7a3b0bd
Reviewed-on: https://go-review.googlesource.com/c/155962
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fix a few missing capitalizations in drive-by.

Change-Id: I7353c12f3ccddefc0f26a98590caf9e446129558
Reviewed-on: https://go-review.googlesource.com/c/163918
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Similar to internal/lazyregexp, this will allow removing unnecessary
work from init functions with trivial refactors, thanks to sync.Once.

Copy the structure. The only major difference is that a template also
carries a name.

For #29382.

Change-Id: I65d096dc2e2072b310bf59a814cd62669856b5b5
Reviewed-on: https://go-review.googlesource.com/c/164337
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This commit add statUnix function for aix/ppc64. It also adds Unix
and Nano methods for AIX time structure.

Change-Id: I9fd62d34a47e87cd46f2f936cb736da0bdff7959
Reviewed-on: https://go-review.googlesource.com/c/163957
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This commit fixes the size of outer symbols like type.*.
Outer symbols cannot have a nil size on AIX or they will be
removed by ld as long as all their sub-symbols.

Change-Id: I68ff3ce5a3a034e3c3eb23431aba31245073cf20
Reviewed-on: https://go-review.googlesource.com/c/163999
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This commit improves symbol table for XCOFF format.
It adds symbol alignment, TLS symbols and move the whole symbol table at
the end of the FILE. As relocations in the future external linking will
need symbols' index, we cannot write the symbol table when it's
generated.

Change-Id: I5dcae85b95e538b65f1a128faf56d4e2aa15baf1
Reviewed-on: https://go-review.googlesource.com/c/163998
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #30446

Change-Id: If069f72fa9735f839df92f3ede3bf7b6d7a695a5
Reviewed-on: https://go-review.googlesource.com/c/164317Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Change-Id: I016312f3ecf3dfcbf0eaf24e31b6842d80abb029
GitHub-Last-Rev: 360047c9006dba643429c006f89d813d927999b3
GitHub-Pull-Request: golang/go#30445
Reviewed-on: https://go-review.googlesource.com/c/164257
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This commit fixes a panic when -a was used with external linkmode.

Fixes #29807

Change-Id: I8cd42775f2953cec620cbc9ab345421c2694c9a2
Reviewed-on: https://go-review.googlesource.com/c/158998Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I50668a4c943ecab91b2b33370f6cfb3784afafd1
GitHub-Last-Rev: c8223adfc8b7d3fc712089bb9cb03d6832ab558b
GitHub-Pull-Request: golang/go#29654
Reviewed-on: https://go-review.googlesource.com/c/157338
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Filippo Valsorda <filippo@golang.org>

These regexes are all related to commands like get and build, so they're
unnecessary for simpler commands like env. In particular, we need env to
be fast, since libraries like go/packages call it early and often. Some
external Go tools are interactive, so milliseconds matter.

lazyregexp eagerly compiles the patterns when running from within a test
binary, so there's no longer any need to do that as part of non-test
binaries.

Picking up the low-hanging fruit spotted by 'perf record' shaves off
well over a full millisecond off the benchmark on my laptop:

name         old time/op    new time/op    delta
ExecGoEnv-8    4.92ms ± 1%    3.81ms ± 0%  -22.52%  (p=0.004 n=6+5)

This CL required adding a few more methods to the lazy regexp wrapper.

Updates #29382.

Change-Id: I22417ab6258f7437a2feea0d25ceb2bb4d735a15
Reviewed-on: https://go-review.googlesource.com/c/155540
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
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Improve error messages if ParsePKCS8PrivateKey/ParseECPrivateKey
/ParsePKCS1PrivateKey or ParsePKIXPublicKey/ParsePKCS1PublicKey
are called erroneously instead of one another.

Fixes #30094

Change-Id: Ia419c5f320167791aa82e174b4e9ce0f3275ec63
Reviewed-on: https://go-review.googlesource.com/c/161557Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Partly implements proposal Issue #29934.

Change-Id: Ibcf12f383158dcfbc313ab29c417a710571d1acb
Reviewed-on: https://go-review.googlesource.com/c/163559
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>

Unwrap, Is and As are as defined in proposal
Issue #29934.

Also add Opaque for enforcing an error cannot
be unwrapped.

Change-Id: I4f3feaa42e3ee7477b588164ac622ba4d5e77cad
Reviewed-on: https://go-review.googlesource.com/c/163558
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>

errors.New now implements Formatter and includes Frame
information that is reported when detail is requested.

Partly implements proposal Issue #29934.

Change-Id: Id76888d246d7d862595b5e92d517b9c03f23a7a6
Reviewed-on: https://go-review.googlesource.com/c/163557
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>

The proposed change introduces a better initial guess which is closer to the final value and therefore converges in fewer steps. Consider for example sqrt(8): previously the guess was 8, whereas now it is 4 (and the result is 2). All this change does is it computes the division by two more accurately while it keeps the guess ≥ √x.

Change-Id: I917248d734a7b0488d14a647a063f674e56c4e30
GitHub-Last-Rev: c06d9d4876c8e7d6739f0e4b687e370fe1e9aad7
GitHub-Pull-Request: golang/go#28981
Reviewed-on: https://go-review.googlesource.com/c/163866
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

to be used by errors package for checking assignability
and setting error values in As.

Updates #29934.

Change-Id: I8c1d02a2c6efa0919d54b286cfe8b4edc26da059
Reviewed-on: https://go-review.googlesource.com/c/161759
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Comparing errors using DeepEqual breaks if frame information
is added as proposed in Issue #29934.

Updates #29934.

Change-Id: Ib430c9ddbe588dd1dd51314c408c74c07285e1ff
Reviewed-on: https://go-review.googlesource.com/c/162179
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>