internal/traceparser: provide parser that uses less space and parses segments of runtime trace files

Traceparser generally takes 20-30% less space than internal/trace. The only
user of these pakcages is cmd/trace, and the new package lets it handle some
trace files that were too large. The new parser will also convert segments
of the raw trace file (e.g. the last 10 seconds) to Events. Trace files from
go 1.8 and before are not supported.

Change-Id: If83fa183246db8f75182ccd3ba8df07673c0ebd0
Reviewed-on: https://go-review.googlesource.com/c/137635
Run-TryBot: Peter Weinberger <pjw@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

The code path for []byte is unused.
Rename function to stringtoruneslit to reflect change in the behavior.

Note that removed code had a bug in it,
it used [0] index instead of [i] inside a loop body.

Change-Id: I58ece5d9d3835887b014446f8a7d3e7fc2fdcaa3
Reviewed-on: https://go-review.googlesource.com/c/125796
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

This improves performance for slices with an element size larger
than 32 bytes and removes loading a value from the maxElems
array for smaller element sizes.

name                 old time/op  new time/op  delta
MakeSlice/Byte       18.0ns ± 4%  18.0ns ± 2%     ~     (p=0.575 n=20+17)
MakeSlice/Int16      21.8ns ± 2%  21.6ns ± 1%   -0.63%  (p=0.035 n=20+19)
MakeSlice/Int        42.0ns ± 2%  41.6ns ± 1%     ~     (p=0.121 n=20+18)
MakeSlice/Ptr        62.6ns ± 2%  62.4ns ± 2%     ~     (p=0.491 n=20+18)
MakeSlice/Struct/24  57.4ns ± 3%  56.0ns ± 2%   -2.40%  (p=0.000 n=19+19)
MakeSlice/Struct/32  62.1ns ± 2%  60.6ns ± 3%   -2.43%  (p=0.000 n=20+20)
MakeSlice/Struct/40  77.3ns ± 3%  68.9ns ± 3%  -10.91%  (p=0.000 n=20+20)

Updates #21588

Change-Id: Ie12807bf8f77c0e15453413f47e3d7de771b798f
Reviewed-on: https://go-review.googlesource.com/c/142377
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

This improves performance for slices with an element size larger
than 32 bytes and removes loading a value from the maxElems
array for smaller element sizes.

name                 old time/op  new time/op  delta
GrowSlice/Byte       41.4ns ± 2%  41.5ns ± 1%    ~     (p=0.366 n=10+9)
GrowSlice/Int16      51.1ns ± 2%  51.0ns ± 2%    ~     (p=0.985 n=10+10)
GrowSlice/Int        64.0ns ± 1%  64.2ns ± 1%    ~     (p=0.180 n=10+10)
GrowSlice/Ptr        90.8ns ± 1%  90.7ns ± 1%    ~     (p=0.858 n=9+10)
GrowSlice/Struct/24   108ns ± 0%   108ns ± 2%    ~     (p=0.488 n=8+9)
GrowSlice/Struct/32   118ns ± 2%   117ns ± 2%    ~     (p=0.327 n=10+10)
GrowSlice/Struct/40   159ns ± 1%   148ns ± 1%  -6.87%  (p=0.000 n=10+9)

Updates #21588

Change-Id: I443b82972d379b1befa791f9ee468b3adc6bb760
Reviewed-on: https://go-review.googlesource.com/c/143798
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This improves performance for maps with a bucket size
(key+value*8 bytes) larger than 32 bytes and removes loading
a value from the maxElems array for smaller bucket sizes.

name                old time/op  new time/op  delta
MakeMap/[Byte]Byte  93.5ns ± 1%  91.8ns ± 1%  -1.83%  (p=0.000 n=10+10)
MakeMap/[Int]Int     134ns ± 1%   127ns ± 2%  -5.61%  (p=0.000 n=9+10)

Updates #21588

Change-Id: I53f77186769c4bd0f2b90f3c6c17df643b060e39
Reviewed-on: https://go-review.googlesource.com/c/143797
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This commit improves the interface_aix.go file, based on feedbacks about
CL 138724.

To retrieve MTU, ioctl is needed. It's implemented inside
internal/syscall/unix.

Change-Id: Ic583d26b93935a32a5f1eb5a2170b86e80a4a85e
Reviewed-on: https://go-review.googlesource.com/c/142157
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

prove is able to find 94 occurrences in std cmd where a divisor
can't have the value -1. The change removes
the extraneous fix-up code for these cases.

Fixes #25239

Change-Id: Ic184de971f47cc57c702eb72805b8e291c14035d
Reviewed-on: https://go-review.googlesource.com/c/130215
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Fixes build.

Change-Id: Id3d78ae9e4669371b4ebf29f69217d0809ffb829
Reviewed-on: https://go-review.googlesource.com/c/143917
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #27930

Change-Id: I31ad3fdb74d74152268c59ae4c651cc4c8c1716d
Reviewed-on: https://go-review.googlesource.com/c/142217Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This copies the change to goosList in CL 138115 to the private copy in
cmd/go.

The change introducing the private copy was apparently not made with
Gerrit, but can be seen at
https://github.com/golang/vgo/commit/08359e782fb601567c57f56beb540841c2416d92.
That change says "This is adapted from code in go/build and the rest
of cmd/go. At some point, we should deduplicate them."

Doing another copy for now, rather than something more complex
involving cmd/dist, pending that deduplication.

Change-Id: I9b6e1f63a3a68c002b60a9a97aa367c5cc7801c9
Reviewed-on: https://go-review.googlesource.com/c/143759
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

This commit adds AIX operating system to cmd/cgo package for ppc64
architecture.

It doesn't fully adapt cgo tool to AIX. But it allows to use
go tool cgo -godefs which is really usefull for others packages.

Update: #25893

Change-Id: I38e289cf0122d143ba100986d08229b51b03ddfc
Reviewed-on: https://go-review.googlesource.com/c/138731
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Now that the library allows much larger data, it can kill
machines with less memory.

Fixes #28321

Change-Id: I98e1a5fdf812fd75adfb22bf01542423de405fe2
Reviewed-on: https://go-review.googlesource.com/c/143817Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>

The parser accepts ...T types in parameter lists whereever a type
is permitted; this matches the syntax and allows for more tolerant
parsing and error recovery.

go/types on the other hand assumed that the parser would report
those errors and assumed any outstanding such errors would be due
to otherwise manipulated ASTs leading to invalid ASTs.

go/types further assumed that a parameter list (a, b, c ...int)
was permitted (a couple of tests used such parameter lists).

With this CL, go/types now correctly refuses invalid parameter lists.

Fixes #28281.

Change-Id: Ib788255f7b7819fdb972c7801bb153a53ce2ddf7
Reviewed-on: https://go-review.googlesource.com/c/143857
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

This commit adds AIX operating system to cmd/go package for ppc64
architecture.

Updates: #25893

Change-Id: I2605d10a7833fa2eb197f6db4a52d5919cf93614
Reviewed-on: https://go-review.googlesource.com/c/138732
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The log interface was changed in https://golang.org/cl/2419042.

Change-Id: I3eaddd8a5cfcae961db16555fb1b0ce6770b6334
Reviewed-on: https://go-review.googlesource.com/c/143777Reviewed-by: Rob Pike <r@golang.org>

TBR=khr

Change-Id: Ia5a08f1acd9f37c466829754990733330264f546
Reviewed-on: https://go-review.googlesource.com/c/143758Reviewed-by: Robert Griesemer <gri@golang.org>

The existing code adjusted the receivers of embedded interface methods
to match the embedding interface type. That required cloning (shallow
copying) the embedded methods and destroyed their object identity in
the process. Don't do this anymore. The consequence to clients is that
they might see different methods of an interface having different
receiver types; they are always the type of the interface that explicitly
declared the method (which is what one usually would want, anyway).

Fixes #28282.

Change-Id: I2e6f1497f46affdf7510547a64601de3787367db
Reviewed-on: https://go-review.googlesource.com/c/143757Reviewed-by: Alan Donovan <adonovan@google.com>

Removes statictmp variables from debug_info and the final symbol table.

Fixes #27800

Change-Id: I302c59a04bc3f460e7085fef241f937bbf30421d
Reviewed-on: https://go-review.googlesource.com/c/142577
Run-TryBot: Alessandro Arzilli <alessandro.arzilli@gmail.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>

The second and subsequent return values from f() need to be
converted to the element type of the first return value from f()
(which must be a slice).

Fixes #22327

Change-Id: I5c0a424812c82c1b95b6d124c5626cfc4408bdb6
Reviewed-on: https://go-review.googlesource.com/c/142718Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Current assembler saves constants in Offset which type is int64,
causing 32-bit constants have a incorrect class. This CL reclassifies
constants when opcodes are 32-bit variant, like MOVW, ANDW and
ADDW, etc. Besides, this CL encodes some constants of ADDCON class
as MOVs instructions.

This CL changes the assembler behavior as follows.

1. go assembler ADDW $MOVCON, Rn, Rd
   previous version: MOVD $MOVCON, Rtmp; ADDW Rtmp, Rn, Rd
   current version: MOVW $MOVCON, Rtmp; ADDW Rtmp, Rn, Rd

2. go assembly MOVW $0xaaaaffff, R1
   previous version: treats $0xaaaaffff as VCON, encodes it as MOVW 0x994, R1 (loads it from pool).
   current version: treats $0xaaaaffff as MOVCON, and encodes it into MOVW instructions.

3. go assembly MOVD $0x210000, R1
   previous version: treats $0x210000 as ADDCON, loads it from pool
   current version: treats $0x210000 as MOVCON, and encodes it into MOVD instructions.

Add the test cases.

1. Binary size before/after.
binary                          size change
pkg/linux_arm64                 -1.534KB
pkg/tool/linux_arm64            -0.718KB
go                              -0.32KB
gofmt                           no change

2. go1 benchmark result.
name                     old time/op    new time/op    delta
BinaryTree17-8              6.26s ± 1%     6.28s ± 1%     ~     (p=0.105 n=10+10)
Fannkuch11-8                5.40s ± 0%     5.39s ± 0%   -0.29%  (p=0.028 n=9+10)
FmtFprintfEmpty-8          94.5ns ± 0%    95.0ns ± 0%   +0.51%  (p=0.000 n=10+9)
FmtFprintfString-8          163ns ± 1%     159ns ± 1%   -2.06%  (p=0.000 n=10+9)
FmtFprintfInt-8             200ns ± 1%     196ns ± 1%   -1.99%  (p=0.000 n=9+10)
FmtFprintfIntInt-8          292ns ± 3%     284ns ± 1%   -2.87%  (p=0.001 n=10+9)
FmtFprintfPrefixedInt-8     422ns ± 1%     420ns ± 1%   -0.59%  (p=0.015 n=10+10)
FmtFprintfFloat-8           458ns ± 0%     463ns ± 1%   +1.19%  (p=0.000 n=9+10)
FmtManyArgs-8              1.37µs ± 1%    1.35µs ± 1%   -1.85%  (p=0.000 n=10+10)
GobDecode-8                15.5ms ± 1%    15.3ms ± 1%   -1.82%  (p=0.000 n=10+10)
GobEncode-8                11.7ms ± 5%    11.7ms ± 2%     ~     (p=0.549 n=10+9)
Gzip-8                      622ms ± 0%     624ms ± 0%   +0.23%  (p=0.000 n=10+9)
Gunzip-8                   73.6ms ± 0%    73.8ms ± 1%     ~     (p=0.077 n=9+9)
HTTPClientServer-8          115µs ± 1%     115µs ± 1%     ~     (p=0.796 n=10+10)
JSONEncode-8               31.1ms ± 2%    28.7ms ± 1%   -7.98%  (p=0.000 n=10+9)
JSONDecode-8                145ms ± 0%     145ms ± 1%     ~     (p=0.447 n=9+10)
Mandelbrot200-8            9.67ms ± 0%    9.60ms ± 0%   -0.76%  (p=0.000 n=9+9)
GoParse-8                  7.56ms ± 1%    7.58ms ± 0%   +0.21%  (p=0.035 n=10+9)
RegexpMatchEasy0_32-8       208ns ±10%     222ns ± 0%     ~     (p=0.531 n=10+6)
RegexpMatchEasy0_1K-8       699ns ± 4%     694ns ± 4%     ~     (p=0.868 n=10+10)
RegexpMatchEasy1_32-8       186ns ± 8%     190ns ±12%     ~     (p=0.955 n=10+10)
RegexpMatchEasy1_1K-8      1.13µs ± 1%    1.05µs ± 2%   -6.64%  (p=0.000 n=10+10)
RegexpMatchMedium_32-8      316ns ± 7%     288ns ± 1%   -8.68%  (p=0.000 n=10+7)
RegexpMatchMedium_1K-8     90.2µs ± 0%    85.5µs ± 2%   -5.19%  (p=0.000 n=10+10)
RegexpMatchHard_32-8       5.53µs ± 0%    3.90µs ± 0%  -29.52%  (p=0.000 n=10+10)
RegexpMatchHard_1K-8        119µs ± 0%     124µs ± 0%   +4.29%  (p=0.000 n=9+10)
Revcomp-8                   1.07s ± 0%     1.07s ± 0%     ~     (p=0.094 n=9+9)
Template-8                  162ms ± 1%     160ms ± 2%     ~     (p=0.089 n=10+10)
TimeParse-8                 756ns ± 2%     763ns ± 1%     ~     (p=0.158 n=10+10)
TimeFormat-8                758ns ± 1%     746ns ± 1%   -1.52%  (p=0.000 n=10+10)

name                     old speed      new speed      delta
GobDecode-8              49.4MB/s ± 1%  50.3MB/s ± 1%   +1.84%  (p=0.000 n=10+10)
GobEncode-8              65.6MB/s ± 5%  65.4MB/s ± 2%     ~     (p=0.549 n=10+9)
Gzip-8                   31.2MB/s ± 0%  31.1MB/s ± 0%   -0.24%  (p=0.000 n=9+9)
Gunzip-8                  264MB/s ± 0%   263MB/s ± 1%     ~     (p=0.073 n=9+9)
JSONEncode-8             62.3MB/s ± 2%  67.7MB/s ± 1%   +8.67%  (p=0.000 n=10+9)
JSONDecode-8             13.4MB/s ± 0%  13.4MB/s ± 1%     ~     (p=0.508 n=9+10)
GoParse-8                7.66MB/s ± 1%  7.64MB/s ± 0%   -0.23%  (p=0.049 n=10+9)
RegexpMatchEasy0_32-8     154MB/s ± 9%   143MB/s ± 3%     ~     (p=0.303 n=10+7)
RegexpMatchEasy0_1K-8    1.46GB/s ± 4%  1.47GB/s ± 4%     ~     (p=0.912 n=10+10)
RegexpMatchEasy1_32-8     172MB/s ± 9%   170MB/s ±12%     ~     (p=0.971 n=10+10)
RegexpMatchEasy1_1K-8     908MB/s ± 1%   972MB/s ± 2%   +7.12%  (p=0.000 n=10+10)
RegexpMatchMedium_32-8   3.17MB/s ± 7%  3.46MB/s ± 1%   +9.14%  (p=0.000 n=10+7)
RegexpMatchMedium_1K-8   11.3MB/s ± 0%  12.0MB/s ± 2%   +5.51%  (p=0.000 n=10+10)
RegexpMatchHard_32-8     5.78MB/s ± 0%  8.21MB/s ± 0%  +41.93%  (p=0.000 n=9+10)
RegexpMatchHard_1K-8     8.62MB/s ± 0%  8.27MB/s ± 0%   -4.11%  (p=0.000 n=9+10)
Revcomp-8                 237MB/s ± 0%   237MB/s ± 0%     ~     (p=0.081 n=9+9)
Template-8               12.0MB/s ± 1%  12.1MB/s ± 2%     ~     (p=0.072 n=10+10)

Change-Id: I080801f520366b42d5f9699954bd33106976a81b
Reviewed-on: https://go-review.googlesource.com/c/120661
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

This change implements mulWW as an intrinsic for ppc64x. Performance
numbers below:

name                            old time/op    new time/op    delta
QuoRem                            4.54µs ±45%    3.22µs ± 0%  -29.22%  (p=0.029 n=4+4)
ModSqrt225_Tonelli                 765µs ± 3%     757µs ± 0%   -1.02%  (p=0.029 n=4+4)
ModSqrt225_3Mod4                   231µs ± 0%     231µs ± 0%   -0.10%  (p=0.029 n=4+4)
ModSqrt231_Tonelli                 789µs ± 0%     788µs ± 0%   -0.14%  (p=0.029 n=4+4)
ModSqrt231_5Mod8                   267µs ± 0%     267µs ± 0%   -0.13%  (p=0.029 n=4+4)
Sqrt                              49.5µs ±17%    45.3µs ± 0%   -8.48%  (p=0.029 n=4+4)
IntSqr/1                          32.2ns ±22%    24.2ns ± 0%  -24.79%  (p=0.029 n=4+4)
IntSqr/2                          60.6ns ± 0%    60.9ns ± 0%   +0.50%  (p=0.029 n=4+4)
IntSqr/3                          82.8ns ± 0%    83.3ns ± 0%   +0.51%  (p=0.029 n=4+4)
IntSqr/5                           122ns ± 0%     121ns ± 0%   -1.22%  (p=0.029 n=4+4)
IntSqr/8                           227ns ± 0%     226ns ± 0%   -0.44%  (p=0.029 n=4+4)
IntSqr/10                          300ns ± 0%     298ns ± 0%   -0.67%  (p=0.029 n=4+4)
IntSqr/20                         1.02µs ± 0%    0.89µs ± 0%  -13.08%  (p=0.029 n=4+4)
IntSqr/30                         1.73µs ± 0%    1.51µs ± 0%  -12.73%  (p=0.029 n=4+4)
IntSqr/50                         3.69µs ± 1%    3.29µs ± 0%  -10.70%  (p=0.029 n=4+4)
IntSqr/80                         7.64µs ± 0%    7.04µs ± 0%   -7.91%  (p=0.029 n=4+4)
IntSqr/100                        11.1µs ± 0%    10.3µs ± 0%   -7.04%  (p=0.029 n=4+4)
IntSqr/200                        37.9µs ± 0%    36.4µs ± 0%   -4.13%  (p=0.029 n=4+4)
IntSqr/300                        69.4µs ± 0%    66.0µs ± 0%   -4.94%  (p=0.029 n=4+4)
IntSqr/500                         174µs ± 0%     168µs ± 0%   -3.10%  (p=0.029 n=4+4)
IntSqr/800                         347µs ± 0%     333µs ± 0%   -4.06%  (p=0.029 n=4+4)
IntSqr/1000                        524µs ± 0%     507µs ± 0%   -3.21%  (p=0.029 n=4+4)

Change-Id: If067452f5b6579ad3a2e9daa76a7ffe6fceae1bb
Reviewed-on: https://go-review.googlesource.com/c/143217
Run-TryBot: Giovanni Bajo <rasky@develer.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>

A little shift magic makes it easy to adjust the maximum buffer
size on machines with larger integers.

Fixes #27635

Change-Id: I1f26b07a363fbb9730df2377052475fa88bbb781
Reviewed-on: https://go-review.googlesource.com/c/143678
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

A prior attempt at addressing the issue got bogged down in an
endless conversation around the subtleties of Read semantics.
Let's not go there.

Instead, we put the issue to bed, perhaps not in perfect comfort
but well enough, by moving a line of the example so that even
if there is a "benign" error as the issue suggests, the loop
terminates with n and err correctly set.

Fixes #27818

Change-Id: I4a32d56c9e782f17578565d90b22ce531e3d8667
Reviewed-on: https://go-review.googlesource.com/c/143677Reviewed-by: Ian Lance Taylor <iant@golang.org>

This fixes the build with go1.4 during bootstrap.

Change-Id: I35fa1dc3d877d31d5ffe515f5f19188f4a8b77f4
Reviewed-on: https://go-review.googlesource.com/c/143377
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

As of golang.org/cl/141857 the import path has changed from
golang.org/x/tour/gotour to golang.org/x/tour

Change-Id: Ib54ab2e50188ef66c8a5c45136babfa49ad6934a
Reviewed-on: https://go-review.googlesource.com/c/141917
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Before this change running os.Stdout.Sync() in the browser would panic
the application with:

panic: syscall/js: Value.Call: property fsync is not a function, got undefined

Afterwards Sync() becomes a noop for compatibility reasons.

Change-Id: I1fcef694beb35fdee3173f87371e1ff233b15d32
Reviewed-on: https://go-review.googlesource.com/c/143138Reviewed-by: Richard Musiol <neelance@gmail.com>
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Keeps the longtest builder green for now.
Proper fix to come ASAP.

Also, reword an internal comment that could easily be misread.

Updates #28282.

Change-Id: I8f41c9faa5a3eb638e6204bae3ff374ed49e5177
Reviewed-on: https://go-review.googlesource.com/c/143478
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The goal of this change is to move work from walk to SSA,
and simplify things along the way.

This is hard to accomplish cleanly with small incremental changes,
so this large commit message aims to provide a roadmap to the diff.

High level description:

Prior to this change, walk was responsible for constructing (most of) the stack for function calls.
ascompatte gathered variadic arguments into a slice.
It also rewrote n.List from a list of arguments to a list of assignments to stack slots.
ascompatte was called multiple times to handle the receiver in a method call.
reorder1 then introduced temporaries into n.List as needed to avoid smashing the stack.
adjustargs then made extra stack space for go/defer args as needed.

Node to SSA construction evaluated all the statements in n.List,
and issued the function call, assuming that the stack was correctly constructed.
Intrinsic calls had to dig around inside n.List to extract the arguments,
since intrinsics don't use the stack to make function calls.

This change moves stack construction to the SSA construction phase.
ascompatte, now called walkParams, does all the work that ascompatte and reorder1 did.
It handles variadic arguments, inserts the method receiver if needed, and allocates temporaries.
It does not, however, make any assignments to stack slots.
Instead, it moves the function arguments to n.Rlist, leaving assignments to temporaries in n.List.
(It would be better to use Ninit instead of List; future work.)
During SSA construction, after doing all the temporary assignments in n.List,
the function arguments are assigned to stack slots by
constructing the appropriate SSA Value, using (*state).storeArg.
SSA construction also now handles adjustments for go/defer args.
This change also simplifies intrinsic calls, since we no longer need to undo walk's work.

Along the way, we simplify nodarg by pushing the fp==1 case to its callers, where it fits nicely.

Generated code differences:

There were a few optimizations applied along the way, the old way.
f(g()) was rewritten to do a block copy of function results to function arguments.
And reorder1 avoided introducing the final "save the stack" temporary in n.List.

The f(g()) block copy optimization never actually triggered; the order pass rewrote away g(), so that has been removed.

SSA optimizations mostly obviated the need for reorder1's optimization of avoiding the final temporary.
The exception was when the temporary's type was not SSA-able;
in that case, we got a Move into an autotmp and then an immediate Move onto the stack,
with the autotmp never read or used again.
This change introduces a new rewrite rule to detect such pointless double Moves
and collapse them into a single Move.
This is actually more powerful than the original optimization,
since the original optimization relied on the imprecise Node.HasCall calculation.

The other significant difference in the generated code is that the stack is now constructed
completely in SP-offset order. Prior to this change, the stack was constructed somewhat
haphazardly: first the final argument that Node.HasCall deemed to require a temporary,
then other arguments, then the method receiver, then the defer/go args.
SP-offset is probably a good default order. See future work.

There are a few minor object file size changes as a result of this change.
I investigated some regressions in early versions of this change.

One regression (in archive/tar) was the addition of a single CMPQ instruction,
which would be eliminated were this TODO from flagalloc to be done:
	// TODO: Remove original instructions if they are never used.

One regression (in text/template) was an ADDQconstmodify that is now
a regular MOVQLoad+ADDQconst+MOVQStore, due to an unlucky change
in the order in which arguments are written. The argument change
order can also now be luckier, so this appears to be a wash.

All in all, though there will be minor winners and losers,
this change appears to be performance neutral.

Future work:

Move loading the result of function calls to SSA construction; eliminate OINDREGSP.

Consider pushing stack construction deeper into SSA world, perhaps in an arch-specific pass.
Among other benefits, this would make it easier to transition to a new calling convention.
This would require rethinking the handling of stack conflicts and is non-trivial.

Figure out some clean way to indicate that stack construction Stores/Moves
do not alias each other, so that subsequent passes may do things like
CSE+tighten shared stack setup, do DSE using non-first Stores, etc.
This would allow us to eliminate the minor text/template regression.

Possibly make assignments to stack slots not treated as statements by DWARF.

Compiler benchmarks:

name        old time/op       new time/op       delta
Template          182ms ± 2%        179ms ± 2%  -1.69%  (p=0.000 n=47+48)
Unicode          86.3ms ± 5%       85.1ms ± 4%  -1.36%  (p=0.001 n=50+50)
GoTypes           646ms ± 1%        642ms ± 1%  -0.63%  (p=0.000 n=49+48)
Compiler          2.89s ± 1%        2.86s ± 2%  -1.36%  (p=0.000 n=48+50)
SSA               8.47s ± 1%        8.37s ± 2%  -1.22%  (p=0.000 n=47+50)
Flate             122ms ± 2%        121ms ± 2%  -0.66%  (p=0.000 n=47+45)
GoParser          147ms ± 2%        146ms ± 2%  -0.53%  (p=0.006 n=46+49)
Reflect           406ms ± 2%        403ms ± 2%  -0.76%  (p=0.000 n=48+43)
Tar               162ms ± 3%        162ms ± 4%    ~     (p=0.191 n=46+50)
XML               223ms ± 2%        222ms ± 2%  -0.37%  (p=0.031 n=45+49)
[Geo mean]        382ms             378ms       -0.89%

name        old user-time/op  new user-time/op  delta
Template          219ms ± 3%        216ms ± 3%  -1.56%  (p=0.000 n=50+48)
Unicode           109ms ± 6%        109ms ± 5%    ~     (p=0.190 n=50+49)
GoTypes           836ms ± 2%        828ms ± 2%  -0.96%  (p=0.000 n=49+48)
Compiler          3.87s ± 2%        3.80s ± 1%  -1.81%  (p=0.000 n=49+46)
SSA               12.0s ± 1%        11.8s ± 1%  -2.01%  (p=0.000 n=48+50)
Flate             142ms ± 3%        141ms ± 3%  -0.85%  (p=0.003 n=50+48)
GoParser          178ms ± 4%        175ms ± 4%  -1.66%  (p=0.000 n=48+46)
Reflect           520ms ± 2%        512ms ± 2%  -1.44%  (p=0.000 n=45+48)
Tar               200ms ± 3%        198ms ± 4%  -0.61%  (p=0.037 n=47+50)
XML               277ms ± 3%        275ms ± 3%  -0.85%  (p=0.000 n=49+48)
[Geo mean]        482ms             476ms       -1.23%

name        old alloc/op      new alloc/op      delta
Template         36.1MB ± 0%       35.3MB ± 0%  -2.18%  (p=0.008 n=5+5)
Unicode          29.8MB ± 0%       29.3MB ± 0%  -1.58%  (p=0.008 n=5+5)
GoTypes           125MB ± 0%        123MB ± 0%  -2.13%  (p=0.008 n=5+5)
Compiler          531MB ± 0%        513MB ± 0%  -3.40%  (p=0.008 n=5+5)
SSA              2.00GB ± 0%       1.93GB ± 0%  -3.34%  (p=0.008 n=5+5)
Flate            24.5MB ± 0%       24.3MB ± 0%  -1.18%  (p=0.008 n=5+5)
GoParser         29.4MB ± 0%       28.7MB ± 0%  -2.34%  (p=0.008 n=5+5)
Reflect          87.1MB ± 0%       86.0MB ± 0%  -1.33%  (p=0.008 n=5+5)
Tar              35.3MB ± 0%       34.8MB ± 0%  -1.44%  (p=0.008 n=5+5)
XML              47.9MB ± 0%       47.1MB ± 0%  -1.86%  (p=0.008 n=5+5)
[Geo mean]       82.8MB            81.1MB       -2.08%

name        old allocs/op     new allocs/op     delta
Template           352k ± 0%         347k ± 0%  -1.32%  (p=0.008 n=5+5)
Unicode            342k ± 0%         339k ± 0%  -0.66%  (p=0.008 n=5+5)
GoTypes           1.29M ± 0%        1.27M ± 0%  -1.30%  (p=0.008 n=5+5)
Compiler          4.98M ± 0%        4.87M ± 0%  -2.14%  (p=0.008 n=5+5)
SSA               15.7M ± 0%        15.2M ± 0%  -2.86%  (p=0.008 n=5+5)
Flate              233k ± 0%         231k ± 0%  -0.83%  (p=0.008 n=5+5)
GoParser           296k ± 0%         291k ± 0%  -1.54%  (p=0.016 n=5+4)
Reflect           1.05M ± 0%        1.04M ± 0%  -0.65%  (p=0.008 n=5+5)
Tar                343k ± 0%         339k ± 0%  -0.97%  (p=0.008 n=5+5)
XML                432k ± 0%         426k ± 0%  -1.19%  (p=0.008 n=5+5)
[Geo mean]         815k              804k       -1.35%

name        old object-bytes  new object-bytes  delta
Template          505kB ± 0%        505kB ± 0%  -0.01%  (p=0.008 n=5+5)
Unicode           224kB ± 0%        224kB ± 0%    ~     (all equal)
GoTypes          1.82MB ± 0%       1.83MB ± 0%  +0.06%  (p=0.008 n=5+5)
Flate             324kB ± 0%        324kB ± 0%  +0.00%  (p=0.008 n=5+5)
GoParser          402kB ± 0%        402kB ± 0%  +0.04%  (p=0.008 n=5+5)
Reflect          1.39MB ± 0%       1.39MB ± 0%  -0.01%  (p=0.008 n=5+5)
Tar               449kB ± 0%        449kB ± 0%  -0.02%  (p=0.008 n=5+5)
XML               598kB ± 0%        597kB ± 0%  -0.05%  (p=0.008 n=5+5)

Change-Id: Ifc9d5c1bd01f90171414b8fb18ffe2290d271143
Reviewed-on: https://go-review.googlesource.com/c/114797
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Currently, WASM binary writer requests 16 int registers (locals) and
16 float registers for every function regardless of how many locals the
function uses.

This change counts the number of used registers and requests a number
of locals matching the highest register index. The change has no effect
on performance and neglectable binary size improvement, but it makes
WASM code more readable and easy to analyze.

Change-Id: Ic1079623c0d632b215c68482db909fa440892700
GitHub-Last-Rev: 184634fa918aff74e280904dc2efafcc80735a8b
GitHub-Pull-Request: golang/go#28116
Reviewed-on: https://go-review.googlesource.com/c/140999Reviewed-by: Richard Musiol <neelance@gmail.com>
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Per the spec clarification https://golang.org/cl/142757 (issue #27995).

Fixes #28251.
Updates #27995.

Change-Id: Idc142829955f9306a8698c5ed1c24baa8ee2b109
Reviewed-on: https://go-review.googlesource.com/c/143179Reviewed-by: Alan Donovan <adonovan@google.com>

Because the code type-checks T rather than ...T (and then corrects
the type to []T "manually"), it didn't automatically record the
type for the ast.Expr corresponding to ...T. Do it manually.

Fixes #28277.

Change-Id: I3d9aae310c90b01f52d189e70c48dd9007f72207
Reviewed-on: https://go-review.googlesource.com/c/143317Reviewed-by: Alan Donovan <adonovan@google.com>

It's no longer needed after removing safemode.

Change-Id: I7581d77a86342e3b6d7c632839f5eb7a5c20902e
Reviewed-on: https://go-review.googlesource.com/c/143397
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The existing code assumed that comparability and orderedness
was implied for the 2nd operand if the 1st operand satisfied
these predicates.

Fixes #28164.

Change-Id: I61d4e5eedb3297731a20a14acb3645d11b36fcc5
Reviewed-on: https://go-review.googlesource.com/c/143277
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

This commit adds the change on asm_ppc64.s and tls_ppc64.s files for AIX
operating system.

R2 does not need to be set for aix/ppc64 since it should remain valid
througout Go execution, except after a call to a C function.
Moreover, g must always be saved on the tls as syscalls are made with
C functions.

Some modifications on asm_ppc64.s are due to AIX stack layout.

It also removes a useless part in asmcgocall which was done twice.

Change-Id: Ie037ab73da00562bb978f2d0f17fcdabd4a40aa2
Reviewed-on: https://go-review.googlesource.com/c/138735
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This commit adds a new package in cmd/internal which aims
to debug and load XCOFF files.

Updates: #25893, #28037

Change-Id: I47db495bedfa43e9129a831b9b8bbc35b703567b
Reviewed-on: https://go-review.googlesource.com/c/138727
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

crypto/tls is meant to work over network connections with buffering, not
synchronous connections, as explained in #24198. Tests based on net.Pipe
are unrealistic as reads and writes are matched one to one. Such tests
worked just thanks to the implementation details of the tls.Conn
internal buffering, and would break if for example the flush of the
first flight of the server was not entirely assimilated by the client
rawInput buffer before the client attempted to reply to the ServerHello.

Note that this might run into the Darwin network issues at #25696.

Fixed a few test races that were either hidden or synchronized by the
use of the in-memory net.Pipe.

Also, this gets us slightly more realistic benchmarks, reflecting some
syscall cost of Read and Write operations.

Change-Id: I5a597b3d7a81b8ccc776030cc837133412bf50f8
Reviewed-on: https://go-review.googlesource.com/c/142817
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Recent change golang.org/cl/142737 drops the only call site for the
sortKeys function. If it's not in use, it should probably not be there in
the code, lurking and preparing to bite us when someone calls that instead
of the new key sorter in fmtsort, resulting in strange inconsistencies.

Since the function isn't called, this should have no impact.
Related to, but does not fix, #21095.

Change-Id: I4695503ef4d5ce90d989ec952f01ea00cc15c79d
Reviewed-on: https://go-review.googlesource.com/c/143178Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Return a consistently formatted error string that reports either
a parse error or a range error.

Before:
	invalid boolean value "3" for -debug: strconv.ParseBool: parsing "3": invalid syntax

After:
	invalid boolean value "3" for -debug: parse error

Fixes #26822

Change-Id: I60992bf23da32a4c0cf32472a8af486a3c9674ad
Reviewed-on: https://go-review.googlesource.com/c/143257Reviewed-by: Ian Lance Taylor <iant@golang.org>

This CL add 3 rules to combine byte-store to word-store on386 and
amd64.

Change-Id: Iffd9cda42f1961680c81def4edc773ad58f211b3
Reviewed-on: https://go-review.googlesource.com/c/143057
Run-TryBot: Ben Shi <powerman1st@163.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

For symmetry with go/types.Identical.

Passes toolstash-check.

Change-Id: Id19c3956e44ed8e2d9f203d15824322cc5842d3d
Reviewed-on: https://go-review.googlesource.com/c/143180
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>