The checkAVX2 test doesn't appear to be correct,
because it always returns the value of support_bmi2,
even if the value of support_avx2 is false.

Consequently, checkAVX2 always returns true, as long
as BMI2 is supported, even if AVX2 is not supported.

We change checkAVX2 to return false when support_avx2
is false.

Fixes #19316.

Change-Id: I2ec9dfaa09f4b54c4a03d60efef891b955d60578
Reviewed-on: https://go-review.googlesource.com/37590
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Fixes #18376.

Change-Id: I4fe24f479311cd4cd1bdad9a966b681e50e3d500
Reviewed-on: https://go-review.googlesource.com/35955Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

During benchmark of an internal tool we found out that (*Buffer).Reset() was
surprisingly showing up in CPU profiles.

This CL contains two related changes aimed at speeding up Reset():
1. Create a fast path for Truncate(0) by moving the logic to Reset()
   (this makes Reset() a simple leaf func that gets inlined since it
   gets compiled to 3 MOVx instructions). Accordingly change calls in
   the rest of the Buffer methods to call Reset() instead of Truncate(0).
2. Reorder the fields in the Buffer struct so that frequently accessed
   fields are packed together (buf, off, lastRead). This also make them
   likely to be in the same cacheline.

Ideally it would be advisable to have Buffer{} cacheline-aligned, but I
couldn't find a way to do this without changing the size of the bootstrap
array (but this will cause some regressions, because it will make duffcopy
show up in CPU profiles where it wasn't showing up before).

go1 benchmarks are not really affected, but some other benchmarks that
exercise Buffer more show improvements:

name                     old time/op    new time/op    delta
BinaryTree17-4              2.46s ± 9%     2.43s ± 3%    ~     (p=0.982 n=14+14)
Fannkuch11-4                2.98s ± 1%     2.90s ± 1%  -2.58%  (p=0.000 n=15+14)
FmtFprintfEmpty-4          45.2ns ± 1%    45.2ns ± 1%    ~     (p=0.494 n=14+15)
FmtFprintfString-4         76.8ns ± 1%    83.1ns ± 2%  +8.23%  (p=0.000 n=10+15)
FmtFprintfInt-4            78.0ns ± 2%    74.6ns ± 1%  -4.46%  (p=0.000 n=15+15)
FmtFprintfIntInt-4          113ns ± 1%     109ns ± 2%  -2.91%  (p=0.000 n=13+15)
FmtFprintfPrefixedInt-4     152ns ± 2%     143ns ± 2%  -6.04%  (p=0.000 n=15+14)
FmtFprintfFloat-4           224ns ± 1%     222ns ± 2%  -1.08%  (p=0.001 n=15+14)
FmtManyArgs-4               464ns ± 2%     463ns ± 2%    ~     (p=0.303 n=14+15)
GobDecode-4                6.25ms ± 2%    6.32ms ± 3%  +1.20%  (p=0.002 n=14+14)
GobEncode-4                5.41ms ± 2%    5.41ms ± 2%    ~     (p=0.967 n=15+15)
Gzip-4                      215ms ± 2%     218ms ± 2%  +1.35%  (p=0.002 n=15+15)
Gunzip-4                   34.3ms ± 2%    34.2ms ± 2%    ~     (p=0.539 n=15+15)
HTTPClientServer-4         76.4µs ± 2%    75.4µs ± 1%  -1.31%  (p=0.000 n=15+15)
JSONEncode-4               14.7ms ± 2%    14.6ms ± 3%    ~     (p=0.094 n=14+14)
JSONDecode-4               48.0ms ± 1%    48.5ms ± 1%  +0.92%  (p=0.001 n=14+12)
Mandelbrot200-4            4.04ms ± 2%    4.06ms ± 1%    ~     (p=0.108 n=15+13)
GoParse-4                  2.99ms ± 2%    3.00ms ± 1%    ~     (p=0.130 n=15+13)
RegexpMatchEasy0_32-4      78.3ns ± 1%    79.5ns ± 1%  +1.51%  (p=0.000 n=15+14)
RegexpMatchEasy0_1K-4       185ns ± 1%     186ns ± 1%  +0.76%  (p=0.005 n=15+15)
RegexpMatchEasy1_32-4      79.0ns ± 2%    76.7ns ± 1%  -2.87%  (p=0.000 n=14+15)

name                     old speed      new speed      delta
GobDecode-4               123MB/s ± 2%   121MB/s ± 3%  -1.18%  (p=0.002 n=14+14)
GobEncode-4               142MB/s ± 2%   142MB/s ± 1%    ~     (p=0.959 n=15+15)
Gzip-4                   90.3MB/s ± 2%  89.1MB/s ± 2%  -1.34%  (p=0.002 n=15+15)
Gunzip-4                  565MB/s ± 2%   567MB/s ± 2%    ~     (p=0.539 n=15+15)
JSONEncode-4              132MB/s ± 2%   133MB/s ± 3%    ~     (p=0.091 n=14+14)
JSONDecode-4             40.4MB/s ± 1%  40.0MB/s ± 1%  -0.92%  (p=0.001 n=14+12)
GoParse-4                19.4MB/s ± 2%  19.3MB/s ± 1%    ~     (p=0.121 n=15+13)
RegexpMatchEasy0_32-4     409MB/s ± 1%   403MB/s ± 1%  -1.47%  (p=0.000 n=15+14)
RegexpMatchEasy0_1K-4    5.53GB/s ± 1%  5.49GB/s ± 1%  -0.86%  (p=0.002 n=15+15)
RegexpMatchEasy1_32-4     405MB/s ± 2%   417MB/s ± 1%  +2.94%  (p=0.000 n=14+15)

name                old time/op  new time/op  delta
PoolsSingle1K-4     34.9ns ± 2%  30.4ns ± 4%  -12.80%  (p=0.000 n=15+15)
PoolsSingle64K-4    36.9ns ± 1%  34.4ns ± 4%   -6.72%  (p=0.000 n=14+15)
PoolsRandomSmall-4  34.8ns ± 3%  29.5ns ± 1%  -15.19%  (p=0.000 n=15+14)
PoolsRandomLarge-4  38.6ns ± 1%  34.3ns ± 3%  -11.17%  (p=0.000 n=14+15)
PoolSingle1K-4      26.1ns ± 1%  21.2ns ± 2%  -18.59%  (p=0.000 n=15+14)
PoolSingle64K-4     26.7ns ± 2%  21.5ns ± 2%  -19.72%  (p=0.000 n=15+15)
MakeSingle1K-4      24.2ns ± 2%  24.3ns ± 3%     ~     (p=0.132 n=13+15)
MakeSingle64K-4     6.76µs ± 1%  6.96µs ± 5%   +2.94%  (p=0.002 n=13+13)
MakeRandomSmall-4    531ns ± 4%   538ns ± 5%     ~     (p=0.066 n=14+15)
MakeRandomLarge-4    152µs ± 0%   152µs ± 1%   -0.31%  (p=0.001 n=14+13)

Change-Id: I86d7d9d2cac65335baf62214fbb35ba0fd8f9528
Reviewed-on: https://go-review.googlesource.com/37416
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fix up and enable a few rules.
They trigger a handful of times in std,
despite the frontend handling.

Change-Id: I83378c057cbbc95a4f2b58cd8c36aec0e9dc547f
Reviewed-on: https://go-review.googlesource.com/37227
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

A type conversion inserted between MOVD{LT,LE,GT,GE,EQ,NE} and CMPWconst
by CL 36256 broke the rewrite rule designed to merge the two.
This results in simple for loops (e.g. for i := 0; i < N; i++ {})
emitting two comparisons instead of one, plus a conditional move.

This CL explicitly types the input to CMPWconst so that the type conversion
can be omitted. It also adds a test to check that conditional moves aren't
emitted for loops with 'less than' conditions (i.e. i < N) on s390x.

Fixes #19227.

Change-Id: Ia39e806ed723791c3c755951aef23f957828ea3e
Reviewed-on: https://go-review.googlesource.com/37334Reviewed-by: Keith Randall <khr@golang.org>

Changes made:
* Adjust the documented form for a URL to make it more obvious what
happens when the scheme is missing.
* Remove references to Go1.5. We are sufficiently far along enough
that this distinction no longer matters.
* Remove the "Opaque" example which provides a hacky and misleading
use of the Opaque field. This workaround is no longer necessary
since RawPath was added in Go1.5 and the obvious approach just works:
	// The raw string "/%2f/" will be sent as expected.
	req, _ := http.NewRequest("GET", "https://example.com/%2f/")

Fixes #18824

Change-Id: Ie33d27222e06025ce8025f8a0f04b601aaee1513
Reviewed-on: https://go-review.googlesource.com/36127
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

For #11415.

Change-Id: I5da39dad059113cfc4276152390aa4925bd18862
Reviewed-on: https://go-review.googlesource.com/37405
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

The comments in cmd/internal/obj/funcdata.go are identical to the
comments in runtime/funcdata.h, but the majority of the definitions
they refer to don't apply to Go sources and have been stripped out of
funcdata.go.

Remove these stale comments from funcdata.go and clean up the
references to other copies of the PCDATA and FUNCDATA indexes.

Change-Id: I5d6e49a6e586cc9aecd7c3ce1567679f2a605884
Reviewed-on: https://go-review.googlesource.com/37330Reviewed-by: Keith Randall <khr@golang.org>

If cgo is not available, parse /etc/group in Go to find the name/gid
we need. This does not consult the Network Information System (NIS),
/etc/nsswitch.conf or any other libc extensions to /etc/group.

Fixes #18102.

Change-Id: I6ae4fe0e2c899396c45cdf243d5483113932657c
Reviewed-on: https://go-review.googlesource.com/33713Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

For #11415.

Change-Id: I87a8f534ab9dfd5022422457ea637b342c057d77
Reviewed-on: https://go-review.googlesource.com/37393Reviewed-by: Alan Donovan <adonovan@google.com>

This is the escape analysis analog of CL 37499.

Fixes #12397
Fixes #16871

The only "moved to heap" decisions eliminated by this
CL in std+cmd are:

cmd/compile/internal/gc/const.go:1514: moved to heap: ac
cmd/compile/internal/gc/const.go:1515: moved to heap: bd
cmd/compile/internal/gc/const.go:1516: moved to heap: bc
cmd/compile/internal/gc/const.go:1517: moved to heap: ad
cmd/compile/internal/gc/const.go:1546: moved to heap: ac
cmd/compile/internal/gc/const.go:1547: moved to heap: bd
cmd/compile/internal/gc/const.go:1548: moved to heap: bc
cmd/compile/internal/gc/const.go:1549: moved to heap: ad
cmd/compile/internal/gc/const.go:1550: moved to heap: cc_plus
cmd/compile/internal/gc/export.go:162: moved to heap: copy
cmd/compile/internal/gc/mpfloat.go:66: moved to heap: b
cmd/compile/internal/gc/mpfloat.go:97: moved to heap: b

Change-Id: I0d420b69c84a41ba9968c394e8957910bab5edea
Reviewed-on: https://go-review.googlesource.com/37508Reviewed-by: David Chase <drchase@google.com>

Keep liveness bit vectors as simple live-variable vectors during
liveness analysis. We can defer expanding them into runtime heap
bitmaps until we're actually writing out the symbol data, and then we
only need temporary memory to expand one bitmap at a time.

This is logically cleaner (e.g., we no longer depend on stack frame
layout during analysis) and saves a little bit on allocations.

name       old alloc/op    new alloc/op    delta
Template      41.4MB ± 0%     41.3MB ± 0%  -0.28%        (p=0.000 n=60+60)
Unicode       32.6MB ± 0%     32.6MB ± 0%  -0.11%        (p=0.000 n=59+60)
GoTypes        119MB ± 0%      119MB ± 0%  -0.35%        (p=0.000 n=60+59)
Compiler       483MB ± 0%      481MB ± 0%  -0.47%        (p=0.000 n=59+60)

name       old allocs/op   new allocs/op   delta
Template        381k ± 1%       380k ± 1%  -0.32%        (p=0.000 n=60+60)
Unicode         325k ± 1%       325k ± 1%    ~           (p=0.867 n=60+60)
GoTypes        1.16M ± 0%      1.15M ± 0%  -0.40%        (p=0.000 n=60+59)
Compiler       4.22M ± 0%      4.19M ± 0%  -0.61%        (p=0.000 n=59+60)

Passes toolstash -cmp.

Change-Id: I8175efe55201ffb5017f79ae6cb90df03f1b7e99
Reviewed-on: https://go-review.googlesource.com/37458
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Static branch prediction assumes that forward branches are not taken.
The existing wrapper prologue almost always takes the first forward
branch.
Move the rare case to the end of the function.

This CL is amd64 only. Other architectures will be done in separate CLs.

Updates #19042.

Package sort benchmarks:

SearchWrappers-8       104ns ± 2%   104ns ± 0%  -0.41%  (p=0.006 n=30+41)
SortString1K-8         128µs ± 1%   128µs ± 1%  -0.25%  (p=0.045 n=30+56)
SortString1K_Slice-8   117µs ± 1%   117µs ± 1%    ~     (p=0.855 n=30+59)
StableString1K-8      18.6µs ± 1%  18.6µs ± 1%    ~     (p=0.599 n=29+60)
SortInt1K-8           61.0µs ± 1%  56.5µs ± 1%  -7.36%  (p=0.000 n=29+58)
StableInt1K-8         74.6µs ± 1%  70.4µs ± 3%  -5.54%  (p=0.000 n=28+60)
StableInt1K_Slice-8   59.9µs ± 1%  58.3µs ± 4%  -2.64%  (p=0.000 n=29+60)
SortInt64K-8          6.02ms ± 2%  5.98ms ± 2%  -0.60%  (p=0.000 n=29+59)
SortInt64K_Slice-8    5.07ms ± 2%  5.05ms ± 2%  -0.38%  (p=0.006 n=30+58)
StableInt64K-8        6.41ms ± 1%  6.22ms ± 1%  -3.00%  (p=0.000 n=27+58)
Sort1e2-8             37.4µs ± 1%  37.1µs ± 1%  -0.91%  (p=0.000 n=30+57)
Stable1e2-8           74.8µs ± 1%  75.2µs ± 1%  +0.52%  (p=0.000 n=30+57)
Sort1e4-8             8.11ms ± 1%  8.01ms ± 1%  -1.20%  (p=0.000 n=30+59)
Stable1e4-8           24.3ms ± 1%  24.3ms ± 1%    ~     (p=0.157 n=30+60)
Sort1e6-8              1.25s ± 1%   1.23s ± 1%  -1.43%  (p=0.000 n=29+58)
Stable1e6-8            4.93s ± 1%   4.90s ± 1%  -0.56%  (p=0.000 n=29+59)
[Geo mean]             720µs        709µs       -1.52%

Assembly for sort.(*intPairs).Swap:

Before:

"".(*intPairs).Swap t=1 size=147 args=0x18 locals=0x8
	0x0000 00000 (<autogenerated>:1)	TEXT	"".(*intPairs).Swap(SB), $8-24
	0x0000 00000 (<autogenerated>:1)	MOVQ	(TLS), CX
	0x0009 00009 (<autogenerated>:1)	SUBQ	$8, SP
	0x000d 00013 (<autogenerated>:1)	MOVQ	BP, (SP)
	0x0011 00017 (<autogenerated>:1)	LEAQ	(SP), BP
	0x0015 00021 (<autogenerated>:1)	MOVQ	32(CX), BX
	0x0019 00025 (<autogenerated>:1)	TESTQ	BX, BX
	0x001c 00028 (<autogenerated>:1)	JEQ	43
	0x001e 00030 (<autogenerated>:1)	LEAQ	16(SP), DI
	0x0023 00035 (<autogenerated>:1)	CMPQ	(BX), DI
	0x0026 00038 (<autogenerated>:1)	JNE	43
	0x0028 00040 (<autogenerated>:1)	MOVQ	SP, (BX)
	0x002b 00043 (<autogenerated>:1)	NOP
	0x002b 00043 (<autogenerated>:1)	FUNCDATA	$0, gclocals·e6397a44f8e1b6e77d0f200b4fba5269(SB)
	0x002b 00043 (<autogenerated>:1)	FUNCDATA	$1, gclocals·69c1753bd5f81501d95132d08af04464(SB)
	0x002b 00043 (<autogenerated>:1)	MOVQ	""..this+16(FP), AX
	0x0030 00048 (<autogenerated>:1)	TESTQ	AX, AX
	0x0033 00051 (<autogenerated>:1)	JEQ	$0, 140
	0x0035 00053 (<autogenerated>:1)	MOVQ	(AX), CX
	0x0038 00056 (<autogenerated>:1)	MOVQ	8(AX), AX
	0x003c 00060 (<autogenerated>:1)	MOVQ	"".i+24(FP), DX
	0x0041 00065 (<autogenerated>:1)	CMPQ	DX, AX
	0x0044 00068 (<autogenerated>:1)	JCC	$0, 133
	0x0046 00070 (<autogenerated>:1)	SHLQ	$4, DX
	0x004a 00074 (<autogenerated>:1)	MOVQ	8(CX)(DX*1), BX
	0x004f 00079 (<autogenerated>:1)	MOVQ	(CX)(DX*1), SI
	0x0053 00083 (<autogenerated>:1)	MOVQ	"".j+32(FP), DI
	0x0058 00088 (<autogenerated>:1)	CMPQ	DI, AX
	0x005b 00091 (<autogenerated>:1)	JCC	$0, 133
	0x005d 00093 (<autogenerated>:1)	SHLQ	$4, DI
	0x0061 00097 (<autogenerated>:1)	MOVQ	8(CX)(DI*1), AX
	0x0066 00102 (<autogenerated>:1)	MOVQ	(CX)(DI*1), R8
	0x006a 00106 (<autogenerated>:1)	MOVQ	R8, (CX)(DX*1)
	0x006e 00110 (<autogenerated>:1)	MOVQ	AX, 8(CX)(DX*1)
	0x0073 00115 (<autogenerated>:1)	MOVQ	SI, (CX)(DI*1)
	0x0077 00119 (<autogenerated>:1)	MOVQ	BX, 8(CX)(DI*1)
	0x007c 00124 (<autogenerated>:1)	MOVQ	(SP), BP
	0x0080 00128 (<autogenerated>:1)	ADDQ	$8, SP
	0x0084 00132 (<autogenerated>:1)	RET
	0x0085 00133 (<autogenerated>:1)	PCDATA	$0, $1
	0x0085 00133 (<autogenerated>:1)	CALL	runtime.panicindex(SB)
	0x008a 00138 (<autogenerated>:1)	UNDEF
	0x008c 00140 (<autogenerated>:1)	PCDATA	$0, $1
	0x008c 00140 (<autogenerated>:1)	CALL	runtime.panicwrap(SB)
	0x0091 00145 (<autogenerated>:1)	UNDEF

After:

"".(*intPairs).Swap t=1 size=149 args=0x18 locals=0x8
	0x0000 00000 (<autogenerated>:1)	TEXT	"".(*intPairs).Swap(SB), $8-24
	0x0000 00000 (<autogenerated>:1)	MOVQ	(TLS), CX
	0x0009 00009 (<autogenerated>:1)	SUBQ	$8, SP
	0x000d 00013 (<autogenerated>:1)	MOVQ	BP, (SP)
	0x0011 00017 (<autogenerated>:1)	LEAQ	(SP), BP
	0x0015 00021 (<autogenerated>:1)	MOVQ	32(CX), BX
	0x0019 00025 (<autogenerated>:1)	TESTQ	BX, BX
	0x001c 00028 (<autogenerated>:1)	JNE	134
	0x001e 00030 (<autogenerated>:1)	NOP
	0x001e 00030 (<autogenerated>:1)	FUNCDATA	$0, gclocals·e6397a44f8e1b6e77d0f200b4fba5269(SB)
	0x001e 00030 (<autogenerated>:1)	FUNCDATA	$1, gclocals·69c1753bd5f81501d95132d08af04464(SB)
	0x001e 00030 (<autogenerated>:1)	MOVQ	""..this+16(FP), AX
	0x0023 00035 (<autogenerated>:1)	TESTQ	AX, AX
	0x0026 00038 (<autogenerated>:1)	JEQ	$0, 127
	0x0028 00040 (<autogenerated>:1)	MOVQ	(AX), CX
	0x002b 00043 (<autogenerated>:1)	MOVQ	8(AX), AX
	0x002f 00047 (<autogenerated>:1)	MOVQ	"".i+24(FP), DX
	0x0034 00052 (<autogenerated>:1)	CMPQ	DX, AX
	0x0037 00055 (<autogenerated>:1)	JCC	$0, 120
	0x0039 00057 (<autogenerated>:1)	SHLQ	$4, DX
	0x003d 00061 (<autogenerated>:1)	MOVQ	8(CX)(DX*1), BX
	0x0042 00066 (<autogenerated>:1)	MOVQ	(CX)(DX*1), SI
	0x0046 00070 (<autogenerated>:1)	MOVQ	"".j+32(FP), DI
	0x004b 00075 (<autogenerated>:1)	CMPQ	DI, AX
	0x004e 00078 (<autogenerated>:1)	JCC	$0, 120
	0x0050 00080 (<autogenerated>:1)	SHLQ	$4, DI
	0x0054 00084 (<autogenerated>:1)	MOVQ	8(CX)(DI*1), AX
	0x0059 00089 (<autogenerated>:1)	MOVQ	(CX)(DI*1), R8
	0x005d 00093 (<autogenerated>:1)	MOVQ	R8, (CX)(DX*1)
	0x0061 00097 (<autogenerated>:1)	MOVQ	AX, 8(CX)(DX*1)
	0x0066 00102 (<autogenerated>:1)	MOVQ	SI, (CX)(DI*1)
	0x006a 00106 (<autogenerated>:1)	MOVQ	BX, 8(CX)(DI*1)
	0x006f 00111 (<autogenerated>:1)	MOVQ	(SP), BP
	0x0073 00115 (<autogenerated>:1)	ADDQ	$8, SP
	0x0077 00119 (<autogenerated>:1)	RET
	0x0078 00120 (<autogenerated>:1)	PCDATA	$0, $1
	0x0078 00120 (<autogenerated>:1)	CALL	runtime.panicindex(SB)
	0x007d 00125 (<autogenerated>:1)	UNDEF
	0x007f 00127 (<autogenerated>:1)	PCDATA	$0, $1
	0x007f 00127 (<autogenerated>:1)	CALL	runtime.panicwrap(SB)
	0x0084 00132 (<autogenerated>:1)	UNDEF
	0x0086 00134 (<autogenerated>:1)	LEAQ	16(SP), DI
	0x008b 00139 (<autogenerated>:1)	CMPQ	(BX), DI
	0x008e 00142 (<autogenerated>:1)	JNE	30
	0x0090 00144 (<autogenerated>:1)	MOVQ	SP, (BX)
	0x0093 00147 (<autogenerated>:1)	JMP	30

Change-Id: Ie8c37f384bba10fbacaa754bb0a6b0a7e520ef01
Reviewed-on: https://go-review.googlesource.com/36893Reviewed-by: Keith Randall <khr@golang.org>

Passes toolstash -cmp.

Change-Id: Ibb51ccaf29ee97c3463543175c9ac7b85ea10a7f
Reviewed-on: https://go-review.googlesource.com/37339Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

These functions are not defined and are not used.

Fixes #19290

Change-Id: I2978147220af83cf319f7439f076c131870fb9ee
Reviewed-on: https://go-review.googlesource.com/37448Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Per suggestion from rsc.

Change-Id: I4b61ec6f35ffaaa792b75e011fbba1bdfbabc1f6
Reviewed-on: https://go-review.googlesource.com/37501
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates http2 to x/net/http2 git rev 906cda9 for:

http2: add configurable knobs for the server's receive window
https://golang.org/cl/37226

http2/hpack: speedup Encoder.searchTable
https://golang.org/cl/37406

http2: Add opt-in option to Framer to allow DataFrame struct reuse
https://golang.org/cl/34812

http2: replace fixedBuffer with dataBuffer
https://golang.org/cl/37400

http2/hpack: remove hpack's constant time string comparison
https://golang.org/cl/37394

Updates golang/go#16512
Updates golang/go#18404

Change-Id: I1ad7c95c404ead4ced7f85af061cf811b299a288
Reviewed-on: https://go-review.googlesource.com/37500Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I0d14d68b57e8605cdae8a45d6fa97255a42297d8
Reviewed-on: https://go-review.googlesource.com/37521
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Constant evaluation provides some rudimentary
knowledge of dead code at inlining decision time.
Use it.

This CL addresses only dead code inside if statements.
For statements are never inlined anyway,
and dead code inside for statements is rare.
Analyzing switch statements is worth doing,
but it is more complicated, since we would have
to evaluate each case; leave it for later.

Fixes #9274

After this CL, the following functions in std+cmd
can be newly inlined:

cmd/internal/obj/x86/asm6.go:3122: can inline subreg
cmd/vendor/golang.org/x/arch/x86/x86asm/decode.go:172: can inline instPrefix
cmd/vendor/golang.org/x/arch/x86/x86asm/decode.go:202: can inline truncated
go/constant/value.go:234: can inline makeFloat
go/types/labels.go:52: can inline (*block).insert
math/big/float.go:231: can inline (*Float).Sign
math/bits/bits.go:57: can inline OnesCount
net/http/server.go:597: can inline (*Server).newConn
runtime/hashmap.go:1165: can inline reflect_maplen
runtime/proc.go:207: can inline os_beforeExit
runtime/signal_unix.go:55: can inline init.5
runtime/stack.go:1081: can inline gostartcallfn

Change-Id: I4c92fb96aa0c3d33df7b3f2da548612e79b56b5b
Reviewed-on: https://go-review.googlesource.com/37499Reviewed-by: Matthew Dempsky <mdempsky@google.com>

If the caller passes a large number to Profile.Add,
the list of pcs is empty, which results in junk
(a nil pc) being recorded. Check for that explicitly,
and replace such stack traces with a lostProfileEvent.

Fixes #18836.

Change-Id: I99c96aa67dd5525cd239ea96452e6e8fcb25ce02
Reviewed-on: https://go-review.googlesource.com/36891Reviewed-by: Russ Cox <rsc@golang.org>

In another CL, I'll add a pure Go implementation of lookupGroup and
lookupGroupId in lookup_unix.go, but attempting that in one CL makes
the diff too difficult to read.

Updates #18102.

Change-Id: If8e26cee5efd30385763430f34304c70165aef32
Reviewed-on: https://go-review.googlesource.com/37497Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

That failing test is preventing other tests from running.
Let's see what else is broken.

Updates #19293

Change-Id: I4c5784be94103ef882f29dec9db08d76a48aff28
Reviewed-on: https://go-review.googlesource.com/37492
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matt Layher <mdlayher@gmail.com>

Measured on 2.3 GHz Intel Core i7, running macOS 10.12.3:

benchmark                old ns/op     new ns/op     delta
BenchmarkReverse8-8      1.70          0.99          -41.76%
BenchmarkReverse16-8     2.24          1.32          -41.07%

Fixes #19279.

Change-Id: I398cf8a3513b7fa63c130efc7846a7c5353999d4
Reviewed-on: https://go-review.googlesource.com/37459
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Iae9fe2db69c02cd442cba01a78820dc7c0fdda51
Reviewed-on: https://go-review.googlesource.com/37462
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Follow-up to CL 37270.

This considerably reduces the time to run the test.

Before:

real	0m7.638s
user	0m14.341s
sys	0m2.244s

After:

real	0m4.867s
user	0m7.107s
sys	0m1.842s

Change-Id: I8837a5da0979a1c365e1ce5874d81708249a4129
Reviewed-on: https://go-review.googlesource.com/37461
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <munday@ca.ibm.com>

Simple change to allow plugins for linux on s390x

Change-Id: I5c262ab81aac10d1dcb03381a48e5b9694b7a87a
Reviewed-on: https://go-review.googlesource.com/37451
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

New special case for booleans and byte-sized integer types
converted to interfaces needs to ensure that the operand is
not too complex, if it were to appear in a parameter list
for example.

Added test, also increased the recursive node dump depth to
a level that was actually useful for an actual bug.

Fixes #19275.

Change-Id: If36ac3115edf439e886703f32d149ee0a46eb2a5
Reviewed-on: https://go-review.googlesource.com/37470
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Change-Id: I3e40018ab1903d3b9ada7ad7812ba71ea2a428e7
Reviewed-on: https://go-review.googlesource.com/37456Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

name                  old time/op  new time/op  delta
ByteByteMap-4         2.03µs ± 2%  1.03µs ± 2%  -49.24%  (p=0.000 n=10+10)
Map/identity/ASCII-4   246ns ± 0%   158ns ± 0%  -35.90%    (p=0.000 n=9+9)
Map/identity/Greek-4   367ns ± 1%   273ns ± 1%  -25.63%  (p=0.000 n=10+10)
Map/change/ASCII-4     582ns ± 1%   324ns ± 1%  -44.34%  (p=0.000 n=10+10)
Map/change/Greek-4     709ns ± 2%   623ns ± 2%  -12.16%  (p=0.000 n=10+10)
MapNoChanges-4         171ns ± 1%   111ns ± 1%  -35.36%   (p=0.000 n=8+10)

Updates #17859

Change-Id: I55d7d261fdc1ce2dcd0ebe23b0fa20b9889bf54c
Reviewed-on: https://go-review.googlesource.com/33201Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The number of open file descriptors reported by lsof is unreliable
because it depends on whether the parent process (the test) closed
the file descriptors it passed into the child process (lsof) before
lsof runs.

Reading /proc/self/fd directly on Linux appears to be much more
reliable and still detects any file descriptor leaks originating
from attempting to run an executable that cannot be found (issue
#5071). If /proc/self/fd is not available (e.g. on Darwin) then we
fall back to lsof and tolerate small differences in open file
descriptor counts.

Fixes #19243.

Change-Id: I052b0c129e609010f1083e43a9911cba154117bf
Reviewed-on: https://go-review.googlesource.com/37343
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Add Set3 function to complement existing Set1 and Set2 functions.
Consistently use Set1, Set2 and Set3 for []*Node instead of Set where applicable.

Add SetFirst and SetSecond for setting elements of []*Node to mirror
First and Second for accessing elements in []*Node.

Replace uses of Index by First and Second and
SetIndex with SetFirst and SetSecond where applicable.

Passes toolstash -cmp.

Change-Id: I8255aae768cf245c8f93eec2e9efa05b8112b4e5
Reviewed-on: https://go-review.googlesource.com/37430
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

TestAssembly was very slow, leading to it being skipped by default.
This is not surprising, it separately invoked the compiler and
parsed the result many times.

Now the test assembles one source file for arch/os combination,
containing the relevant functions.

Tests for each arch/os run in parallel.

Now the test runs approximately 10x faster on my Intel(R) Core(TM)
i5-6600 CPU @ 3.30GHz.

Fixes #18966

Change-Id: I45ab97630b627a32e17900c109f790eb4c0e90d9
Reviewed-on: https://go-review.googlesource.com/37270
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This should help on the openbsd systems where the test mostly passes.

I don't expect it to help on s390x where the test reliably fails.
But it should give more information when it does fail.

For #19276.

Change-Id: I496c291f2b4b0c747b8dd4315477d87d03010059
Reviewed-on: https://go-review.googlesource.com/37348
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I3c31f10c1082c7bc57aac18856014c55f79e0fed
Reviewed-on: https://go-review.googlesource.com/37409Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The profiles are self-contained now.
Check that they work by themselves in the tests that invoke pprof,
but also keep checking that the old command lines work.

Change-Id: I24c74b5456f0b50473883c3640625c6612f72309
Reviewed-on: https://go-review.googlesource.com/37166
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

Nothing needs internal/pprof anymore except the runtime/pprof tests.
Move the package here to prevent new dependencies.

Change-Id: Ia119af91cc2b980e0fa03a15f46f69d7f71d2926
Reviewed-on: https://go-review.googlesource.com/37165
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

The existing code builds a full profile in memory.
Then it translates that profile into a data structure (in memory).
Then it marshals that data structure into a protocol buffer (in memory).
Then it gzips that marshaled form into the underlying writer.
So there are three copies of the full profile data in memory
at the same time before we're done. This is obviously dumb.

This CL implements a fully streaming conversion from
the original in-memory profile to the underlying writer.
There is now only one copy of the profile in memory.

For the non-CPU profiles, this is optimal, since we have to
have a full copy in memory to start with.

For the CPU profiles, we could still try to bound the profile
size stored in memory and stream fragments out during
the actual profiling, as Go 1.7 did (with a simpler format),
but so far that hasn't been necessary.

Change-Id: Ic36141021857791bf0cd1fce84178fb5e744b989
Reviewed-on: https://go-review.googlesource.com/37164
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>

This change adds math/bits as a new dependency of math/big.

- use bits.LeadingZeroes instead of local implementation
  (they are identical, so there's no performance loss here)

- leave other functionality local (ntz, bitLen) since there's
  faster implementations in math/big at the moment

Change-Id: I1218aa8a1df0cc9783583b090a4bb5a8a145c4a2
Reviewed-on: https://go-review.googlesource.com/37141Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Import the github.com/google/pprof and github.com/ianlancetaylor/demangle
packages, without modification.

Build the golang version of pprof from cmd/pprof/pprof.go
by importing the packages from src/cmd/vendot/github.com/google/pprof

The versions upstreamed are:

github.com/ianlancetaylor/demangle 4883227f66371e02c4948937d3e2be1664d9be38
github.com/google/pprof            7eb5ba977f28f2ad8dd5f6bb82cc9b454e123cdc

Update misc/nacl/testzip.proto for new tests.

Change-Id: I076584856491353607a3b98b67d0ca6838be50d6
Reviewed-on: https://go-review.googlesource.com/36798
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Wait a short period between trying commands. Many commands
will return a non-zero exit code if the browser couldn't be launched.

For example, google-chrome returns quickly with a non-zero
exit code in a headless environment.

Updates #19131.

Change-Id: I0ae5356dd4447969d9e216615449cead7a8fd5c9
Reviewed-on: https://go-review.googlesource.com/37391Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>