There are two issues in constant decomposition.

1. A typo in "func immrot2s" blocks "case 107" of []optab be triggered.

2. Though "ADD $0xffff, R0, R0" is decomposed to "ADD $0xff00, R0, R0" and
   "ADD $0x00ff, R0, R0" as expected, "ADD $0xffff, R0" still uses the
   constant pool, which should be the same as "ADD $0xffff, R0, R0".

This patch fixes them and adds more instruction encoding tests.

fix #20516

Change-Id: Icd7bdfa1946b29db15580dcb429111266f1384c6
Reviewed-on: https://go-review.googlesource.com/44335
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Fixes #19526

Change-Id: Ifaaf454e0e89fdf4309118c2e2e6ac0d0a43c39d
Reviewed-on: https://go-review.googlesource.com/44711Reviewed-by: Ian Lance Taylor <iant@golang.org>

Replace int division with (cheaper) byte division in heapBitsSetType.
Provides noticeable speed-up:

GrowSlicePtr-6   181ns ± 3%   169ns ± 3%  -6.85%  (p=0.000 n=10+10)

Change-Id: I4064bb72e8e692023783b8f58d19491844c39382
Reviewed-on: https://go-review.googlesource.com/42290
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Since TestPingPongHog tests the scheduler, it's ultimately
probabilistic. Currently, it requires the result be at most of factor
of 2 off of the ideal. It turns out this isn't quite enough in
practice, with factors on 1000 iterations on linux/amd64 ranging from
0.48 to 2.5. If the test were failing, we would expect a factor closer
to 1000X, so it's pretty safe to expand the accepted factor from 2 to
5.

Fixes #20494.

Change-Id: If8f2e96194fe66f1fb981a965d1167fe74ff38d7
Reviewed-on: https://go-review.googlesource.com/44859
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #17625

Change-Id: I09319b888b547c631a50dbfab9255cc08e8a2426
Reviewed-on: https://go-review.googlesource.com/40691Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

I learned from CL 41770 that valState’s size
matters to compiler performance.
Encode that knowledge in a test.

Change-Id: I7c0fde6a4cf460017619dbcce1c1ddaa7af10239
Reviewed-on: https://go-review.googlesource.com/44737
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

For test.go:

	package main

	import (
	   "C"
	   "fmt"
	)

	func main() {
		 fmt.Println("Hello, world!")
		 C.no_such_f()
	}

Before:

	could not determine kind of name for C.no_such_f

After:

	./test.go:10:2: could not determine kind of name for C.no_such_f

Fixes #18452

Change-Id: I49c136b7fa60fab25d2d5b905d440fe4d106e565
Reviewed-on: https://go-review.googlesource.com/34783
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I98d265bfa4f5944360d0258d2cb6bbc78010c708
Reviewed-on: https://go-review.googlesource.com/44731Reviewed-by: Ian Lance Taylor <iant@golang.org>

1) Split atLineBegin into its two components: writing of // line directives
and writing of indentation (no functionality changes).

2) Don't call writeLineDirective at the beginning of a line if we're
writing white space - it's not necessary. This is the bug fix.

3) Move testing of the SourcePos mode out of writeLineDirective and
into the (single) caller. Clearer and more efficient.

(Instead of these 3 changes one could also have simply called the
original atLineBegin with position p.out rather than p.pos. This
would have caused atLineBegin to not write a line directive.
Factoring the code seemed like a cleaner and more direct approach.)

Fixes #5945.

Change-Id: Ia8710806b6d3d4e5044116b142c036a4ab5a1764
Reviewed-on: https://go-review.googlesource.com/44651Reviewed-by: Alan Donovan <adonovan@google.com>

Fixes #19383

Change-Id: Ic84517053ced7794006f6fc65e6f249e97d6cf35
Reviewed-on: https://go-review.googlesource.com/44691Reviewed-by: Ian Lance Taylor <iant@golang.org>

Defaulting total to 1 for each function, adds up to the
counting error. testing/cover.go already does this once.

Fixes #20515

Change-Id: I0e3f524c2ccb628eb9a8f0a1f81c22365c24cf9a
Reviewed-on: https://go-review.googlesource.com/44337
Run-TryBot: Dhananjay Nakrani <dhananjayn@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Arguments to inlined calls are hidden from setPos as follows:

    args := as.Rlist
    as.Rlist.Set(nil)
    // setPos...
    as.Rlist.Set(args.Slice())

Previously, this code had no effect since the value of as was
overwritten by the assignment in the retvars loop.

Fixes #19799.

Change-Id: Iaf97259f82fdba8b236136337cc42b2774c7fef5
Reviewed-on: https://go-review.googlesource.com/44351
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

The test no longer passes as of https://golang.org/cl/43777, which
intentionally disables the feature that this test was checking for.
Nobody noticed since the test is not run in -short mode.

Updates #20435.

Change-Id: I64f37fd94c01f22ead88470b6d9bfe8a151ddb1c
Reviewed-on: https://go-review.googlesource.com/44650Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>

Fixes #20551

Change-Id: Ia47cae14a26fe5f278ad7209218d083cc50a3ff8
Reviewed-on: https://go-review.googlesource.com/44572Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates #20540

Change-Id: I864008fadd77b0aeb10fe7e7f1ec696516a5add5
Reviewed-on: https://go-review.googlesource.com/44492Reviewed-by: Robert Griesemer <gri@golang.org>

Currently we inline array comparisons for arrays with at most 4 elements.
Compare arrays with small size, but more than 4 elements (e. g. [16]byte)
with larger compares. This provides very slightly smaller binaries,
and results in faster code.

ArrayEqual-6  7.41ns ± 0%  3.17ns ± 0%  -57.15%  (p=0.000 n=10+10)

For go tool:
global text (code) = -559 bytes (-0.014566%)

This also helps mapaccess1_faststr, and maps in general:

MapDelete/Str/1-6               195ns ± 1%     186ns ± 2%   -4.47%  (p=0.000 n=10+10)
MapDelete/Str/2-6               211ns ± 1%     177ns ± 1%  -16.01%  (p=0.000 n=10+10)
MapDelete/Str/4-6               225ns ± 1%     183ns ± 1%  -18.49%  (p=0.000 n=8+10)
MapStringKeysEight_16-6        31.3ns ± 0%    28.6ns ± 0%   -8.63%  (p=0.000 n=6+9)
MapStringKeysEight_32-6        29.2ns ± 0%    27.6ns ± 0%   -5.45%  (p=0.000 n=10+10)
MapStringKeysEight_64-6        29.1ns ± 1%    27.5ns ± 0%   -5.46%  (p=0.000 n=10+10)
MapStringKeysEight_1M-6        29.1ns ± 1%    27.6ns ± 0%   -5.49%  (p=0.000 n=10+10)

Change-Id: I9ec98e41b233031e0e96c4e13d86a324f628ed4a
Reviewed-on: https://go-review.googlesource.com/40771
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

This includes the patch for systems that build PIE executables by
defaul

Updates #20276.

Change-Id: Iecf8dfcf11bc18d397b8075559c37e3610f825cb
Reviewed-on: https://go-review.googlesource.com/44470Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #20540

Change-Id: I440eee02d37b6921613f9ae77875d91eeec48b1e
Reviewed-on: https://go-review.googlesource.com/44490Reviewed-by: Robert Griesemer <gri@golang.org>

Apply the fix in CL 44355 to MIPS.

ARM64 has these rules but commented out for performance reason.
Fix the commented rules, in case they are enabled in the future.

Enhance the test so it triggers the failure on ARM and MIPS without
the fix.

Updates #20530.

Change-Id: I82d77448e3939a545fe519d0a29a164f8fa5417c
Reviewed-on: https://go-review.googlesource.com/44430
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

Fixes #20490

Change-Id: I9cfa604f9ff94df779cb9b4cbbd706258fc473ac
Reviewed-on: https://go-review.googlesource.com/44150
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

The current implementation of forkAndExecInChild for Linux does not allow
spawned processes steal the controlling terminal from a different session
group. This patch passes 1 as the argument to TIOCSCTTY in order to allow
spawned processes steal controlling terminals.

Fixes #20454

Change-Id: I171b8981509d648b07f89bddc1e9d45cb70e00e6
Reviewed-on: https://go-review.googlesource.com/44343Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Block signals explicitly during lwp_create since blocking via
the context does not work.

This was originally added in pkgsrc as
http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/lang/go/patches/patch-src_runtime_os__netbsd.go?rev=1.1

Fixes #19295.

Change-Id: I431e70c047cff446e9cfc20d356f45df98c63487
Reviewed-on: https://go-review.googlesource.com/41350Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This should help narrowing down the possible cause of #20514.

Updates #20514.

Change-Id: Ie997400c9749aace7783bd585b23dbb4cefc181d
Reviewed-on: https://go-review.googlesource.com/44375Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #20529

Change-Id: I3cb0c037b1737fbc3fa3b1b61ed8a42cfaf8e10d
Reviewed-on: https://go-review.googlesource.com/44344
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Replacing byteload-of-bytestore-of-x with x is incorrect
when x contains a larger-than-byte value (and so on for
16 and 32-bit load/store pairs).  Replace "x" with the
appropriate zero/sign extension of x, which if unnecessary
will be repaired by other rules.

Made logic for arm match x86 and amd64; yields minor extra
optimization, plus I am (much) more confident it's correct,
despite inability to reproduce bug on arm.

Ppc64 lacks this optimization, hence lacks this problem.

See related https://golang.org/cl/37154/
Fixes #20530.

Change-Id: I6af9cac2ad43bee99cafdcb04725ce7e55a43323
Reviewed-on: https://go-review.googlesource.com/44355
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Fixes #20394

Change-Id: Iabb2a53fd1ddb783e7fb5b60ced8482c2e2569c4
Reviewed-on: https://go-review.googlesource.com/44377
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Replaced ../gc/reflect.c with
cmd/compile/internal/gc/reflect.go.

Fixes #20525

Change-Id: Ibafd36ea446ace5c677df27873a4bbf716a0a9bc
Reviewed-on: https://go-review.googlesource.com/44376Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates golang_org/x/net/lif to rev fcc8ed8 for:
- lif: rename internal types (http://golang.org/cl/43070)

Change-Id: I0aad9a8b504d673b29d3c26b3717ffa8512e0cdf
Reviewed-on: https://go-review.googlesource.com/44392Reviewed-by: Ian Lance Taylor <iant@golang.org>

key32 is called between entersyscallblock and exitsyscall
stack split may occur if disable inlining and the G is preempted

Fix the problem by describing key32 as nosplit function

Fixes #20510

Change-Id: I1f0787995936f34ef0052cf79fde036f1b338865
Reviewed-on: https://go-review.googlesource.com/44390Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

cmd/compile/internal/ld/decodesym.go is now
cmd/link/internal/ld/decodesym.go

Change-Id: I16ec5c89aa3507e70676c2b50d70f1fde533a085
Reviewed-on: https://go-review.googlesource.com/44373Reviewed-by: Ian Lance Taylor <iant@golang.org>

Vet returns with a nonzero exit for all possible messages in the
buildtag check. However for this file:

    //+buildlinux

    package main

vet returns a zero exit status:

    $ go vet main.go
    demo.go:1: possible malformed +build comment
    $ echo $?
    0

This CL sets the exit status to non zero for the remaining messages in
the buildtag check.

Change-Id: Ia2c35ebc3ec5ac311d2a0295b5b9fdd997a85726
Reviewed-on: https://go-review.googlesource.com/44371Reviewed-by: Rob Pike <r@golang.org>

In preparation for CL 41770, upgrade .debug_info to DWARF4, and emit
DW_AT_frame_base on subprograms. This should make no semantic
difference.

Also fix a long-standing bug/inconsistency in puttattr: it didn't
add the addend to ref_addrs. Previously this didn't matter because it
was only used for types, but now it's used for section offsets into
symbols that have multiple entries.

RELNOTE=yes

Change-Id: Ib10654ac92edfa29c5167c44133648151d70cf76
Reviewed-on: https://go-review.googlesource.com/44210Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Instead of allocating a new reflect.Value object on every loop we zero it.

DecodeComplex128Slice-8  13.1µs ± 7%  13.2µs ± 8%     ~     (p=0.347 n=18+19)
DecodeFloat64Slice-8     8.13µs ± 5%  8.00µs ± 3%     ~     (p=0.168 n=20+19)
DecodeInt32Slice-8       8.27µs ± 5%  8.08µs ± 5%   -2.27%  (p=0.001 n=19+18)
DecodeStringSlice-8      17.9µs ±12%  17.8µs ±11%     ~     (p=0.989 n=20+19)
DecodeInterfaceSlice-8    163µs ±10%   159µs ± 4%     ~     (p=0.057 n=19+19)
DecodeMap-8               220µs ± 2%   183µs ± 1%  -17.07%  (p=0.000 n=19+18)

Updates #19525

Change-Id: I27f8edd4761787f6b9928d34cefa08a34a6e25b2
Reviewed-on: https://go-review.googlesource.com/39203Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This updates the bundled copy of x/net/http2 to x/net git rev
3470a06c1357df53 for:

http2: fix typo in comment
https://golang.org/cl/44271

http2: fix nil dereference after Read completes with an error
https://golang.org/cl/44330

Fixes #20501

Change-Id: Ie6a5fb092f77044f504f146721dae86299e04011
Reviewed-on: https://go-review.googlesource.com/44331
Run-TryBot: Tom Bergan <tombergan@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

See: https://pkware.cachefly.net/webdocs/APPNOTE/APPNOTE-6.3.0.TXT

Document says:
> If general purpose bit 11 is set, the filename and comment must support The
> Unicode Standard, Version 4.1.0 or greater using the character encoding form
> defined by the UTF-8 storage specification.

Since Go encode the filename to UTF-8, general purpose bit 11 should be set.

Change-Id: Ica4af02b4dc695e9a5c015ae360e70171efb6ee3
Reviewed-on: https://go-review.googlesource.com/39570Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This avoids false-positive TSAN reports when using the C sigaction
function to read handlers registered by the Go runtime.

(Unfortunately, I can't seem to coax the runtime into reproducing the
failure in a small unit-test.)

Change-Id: I744279a163708e24b1fbe296ca691935c394b5f3
Reviewed-on: https://go-review.googlesource.com/44270
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

Currently debug/dwarf assumes all paths in line tables will be
UNIX-style paths, which obviously isn't the case for binaries built on
Windows. However, we can't simply switch from the path package to the
filepath package because we don't know that we're running on the same
host type that built the binary and we want this to work even if we're
not. This is essentially the approach taken by GDB, which treats paths
in accordance with the system GDB itself is compiled for. In fact, we
can't even guess the compilation system from the type of the binary
because it may have been cross-compiled.

We fix this by heuristically determining whether paths are UNIX-style
or DOS-style by looking for a drive letter or UNC path. If we see a
DOS-style path, we use appropriate logic for determining whether the
path is absolute and for joining two paths. This is helped by the fact
that we should basically always be starting with an absolute path.
However, it could mistake a relative UNIX-style path that begins with
a directory like "C:" for an absolute DOS-style path. There doesn't
seem to be any way around this.

Fixes #19784.

Change-Id: Ie13b546d2f1dcd8b02e668583a627b571b281588
Reviewed-on: https://go-review.googlesource.com/44017
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

Change-Id: I3b3ae4ecad0894781a3019326c7262cb9790ad4d
Reviewed-on: https://go-review.googlesource.com/44250Reviewed-by: Bryan Mills <bcmills@google.com>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

It is expected to test assembly code for ARMv5, ARMv6 and ARMv7
in cmd/asm/internal/asm/endtoend_test.go. But actually the loop
in "func TestARMEndToEnd(t *testing.T)" runs three times all
for ARMv5.

This patch fixes that bug and adds a new armv6.s which is only tested
with GOARM=6.

fixes #20465

Change-Id: I5dbf00809a47ace2c195335e2c9bdd768479aada
Reviewed-on: https://go-review.googlesource.com/43930Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

"ADDF F0, R1, F2" is silently accepted by the arm assembler and
assembled to the same binary code of "ADDF F0, F1, F2". So does
"CMPF F0, R1".

"ABSF F0, F1, F2" is also silently accepted and assembled to a
different instruction.

This patch reports those illegal forms and adds test cases.

fix #20464

Change-Id: I88b80dc29de24c6266ac7bf7bce1578c5adbc68c
Reviewed-on: https://go-review.googlesource.com/43931
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>