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32762 Commits

Author SHA1 Message Date
Austin Clements
3b5637ff2b runtime: doubly fix "double wakeup" panic
runtime.gchelper depends on the non-atomic load of work.ndone
happening strictly before the atomic add of work.nwait. Until very
recently (commit 978af9c2db, fixing #20334), the compiler reordered
these operations. This created a race since work.ndone can change as
soon as work.nwait is equal to work.ndone. If that happened, more than
one gchelper could attempt to wake up the work.alldone note, causing a
"double wakeup" panic.

This was fixed in the compiler, but to make this code less subtle,
make the load of work.ndone atomic. This clearly forces the order of
these operations, ensuring the race doesn't happen.

Fixes #19305 (though really 978af9c2db fixed it).

Change-Id: Ieb1a84e1e5044c33ac612c8a5ab6297e7db4c57d
Reviewed-on: https://go-review.googlesource.com/43311
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-12 15:33:09 +00:00
Austin Clements
29e88d5130 runtime: print debug info on "base out of range"
This adds debugging information when we panic with "heapBitsForSpan:
base out of range".

Updates #20259.

Change-Id: I0dc1a106aa9e9531051c7d08867ace5ef230eb3f
Reviewed-on: https://go-review.googlesource.com/43310
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-12 14:28:15 +00:00
Ian Lance Taylor
dddd1dd481 cmd/go: fix TestExecutableGOROOT on Windows
On Windows the drive letter is sometime "c:" and sometimes "C:".

Fixes #20336.

Change-Id: I38c86999af9522c51470d60016729d41cfec6b25
Reviewed-on: https://go-review.googlesource.com/43390
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-12 14:26:32 +00:00
Hiroshi Ioka
22538477a3 cmd/go: use filepath.Base for getting $CC name in TestCgoContainsSpace
Change-Id: If7329b81073d7c98fdcb8a2c0b35f8708000606e
Reviewed-on: https://go-review.googlesource.com/43332
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-12 13:30:24 +00:00
Hiroshi Ioka
482da51803 cmd/go: fix TestCgoContainsSpace
TestCgoContainsSpace builds a small program which mimics $CC.
Usually, $CC attempts to compile a trivial code to detect its own
supported flags (i.e. "-no-pie", which must be passed on some systems),
however the mimic didn't consider these cases.

This CL solve the issue.

Also, use the same name as $CC, it may solve other potential problems.

Fixes #20324

Change-Id: I7a00ac016a5fd0667540f2a715371f8152edc395
Reviewed-on: https://go-review.googlesource.com/43330
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-12 01:10:11 +00:00
Keith Randall
978af9c2db cmd/compile: fix store chain in schedule pass
Tuple ops are weird. They are essentially a pair of ops,
one which consumes a mem and one which generates a mem (the Select1).
The schedule pass didn't handle these quite right.

Fix the scheduler to include both parts of the paired op in
the store chain. That makes sure that loads are correctly ordered
with respect to the first of the pair.

Add a check for the ssacheck builder, that there is only one
live store at a time. I thought we already had such a check, but
apparently not...

Fixes #20335

Change-Id: I59eb3446a329100af38d22820b1ca2190ca46a78
Reviewed-on: https://go-review.googlesource.com/43294
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-05-11 22:16:08 +00:00
Josh Bleecher Snyder
e5bb5e397d cmd/compile: restore panic deduplication
The switch to detailed position information broke
the removal of duplicate panics on the same line.
Restore it.

Neutral compiler performance impact:

name        old alloc/op      new alloc/op      delta
Template         38.8MB ± 0%       38.8MB ± 0%    ~     (p=0.690 n=5+5)
Unicode          28.7MB ± 0%       28.7MB ± 0%  +0.13%  (p=0.032 n=5+5)
GoTypes           109MB ± 0%        109MB ± 0%    ~     (p=1.000 n=5+5)
Compiler          457MB ± 0%        457MB ± 0%    ~     (p=0.151 n=5+5)
SSA              1.09GB ± 0%       1.10GB ± 0%  +0.17%  (p=0.008 n=5+5)
Flate            24.6MB ± 0%       24.5MB ± 0%  -0.35%  (p=0.008 n=5+5)
GoParser         30.9MB ± 0%       31.0MB ± 0%    ~     (p=0.421 n=5+5)
Reflect          73.4MB ± 0%       73.4MB ± 0%    ~     (p=0.056 n=5+5)
Tar              25.6MB ± 0%       25.5MB ± 0%  -0.61%  (p=0.008 n=5+5)
XML              40.9MB ± 0%       40.9MB ± 0%    ~     (p=0.841 n=5+5)
[Geo mean]       71.6MB            71.6MB       -0.07%

name        old allocs/op     new allocs/op     delta
Template           394k ± 0%         395k ± 1%    ~     (p=0.151 n=5+5)
Unicode            343k ± 0%         344k ± 0%  +0.38%  (p=0.032 n=5+5)
GoTypes           1.16M ± 0%        1.16M ± 0%    ~     (p=1.000 n=5+5)
Compiler          4.41M ± 0%        4.42M ± 0%    ~     (p=0.151 n=5+5)
SSA               9.79M ± 0%        9.79M ± 0%    ~     (p=0.690 n=5+5)
Flate              238k ± 1%         238k ± 0%    ~     (p=0.151 n=5+5)
GoParser           321k ± 0%         321k ± 1%    ~     (p=0.548 n=5+5)
Reflect            958k ± 0%         957k ± 0%    ~     (p=0.841 n=5+5)
Tar                252k ± 0%         252k ± 1%    ~     (p=0.151 n=5+5)
XML                401k ± 0%         400k ± 0%    ~     (p=1.000 n=5+5)
[Geo mean]         741k              742k       +0.08%


Reduces object files a little bit:

name        old object-bytes  new object-bytes  delta
Template           386k ± 0%         386k ± 0%  -0.04%  (p=0.008 n=5+5)
Unicode            202k ± 0%         202k ± 0%    ~     (all equal)
GoTypes           1.16M ± 0%        1.16M ± 0%  -0.04%  (p=0.008 n=5+5)
Compiler          3.91M ± 0%        3.91M ± 0%  -0.08%  (p=0.008 n=5+5)
SSA               7.91M ± 0%        7.91M ± 0%  -0.04%  (p=0.008 n=5+5)
Flate              228k ± 0%         227k ± 0%  -0.28%  (p=0.008 n=5+5)
GoParser           283k ± 0%         283k ± 0%  -0.01%  (p=0.008 n=5+5)
Reflect            952k ± 0%         951k ± 0%  -0.03%  (p=0.008 n=5+5)
Tar                188k ± 0%         187k ± 0%  -0.09%  (p=0.008 n=5+5)
XML                406k ± 0%         406k ± 0%  -0.04%  (p=0.008 n=5+5)
[Geo mean]         648k              648k       -0.06%


This was discovered in the context for the Fannkuch benchmark.
It shrinks the number of panicindex calls in that function
from 13 back to 9, their 1.8.1 level.

It shrinks the function text a bit, from 829 to 801 bytes.
It slows down execution a little, presumably due to alignment (?).

name          old time/op  new time/op  delta
Fannkuch11-8   2.68s ± 2%   2.74s ± 1%  +2.09%  (p=0.000 n=19+20)

After this CL, 1.8.1 and tip are identical:

name          old time/op  new time/op  delta
Fannkuch11-8   2.74s ± 2%   2.74s ± 1%   ~     (p=0.301 n=20+20)

Fixes #20332

Change-Id: I2aeacc3e8cf2ac1ff10f36c572a27856f4f8f7c9
Reviewed-on: https://go-review.googlesource.com/43291
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-11 19:34:11 +00:00
Josh Bleecher Snyder
ee69c21747 cmd/compile: don't use statictmps for SSA-able composite literals
The writebarrier test has to change.
Now that T23 composite literals are passed to the backend,
they get SSA'd, so writes to their fields are treated separately,
so the relevant part of the first write to t23 is now a dead store.
Preserve the intent of the test by splitting it up into two functions.

Reduces code size a bit:

name        old object-bytes  new object-bytes  delta
Template           386k ± 0%         386k ± 0%    ~     (all equal)
Unicode            202k ± 0%         202k ± 0%    ~     (all equal)
GoTypes           1.16M ± 0%        1.16M ± 0%    ~     (all equal)
Compiler          3.92M ± 0%        3.91M ± 0%  -0.19%  (p=0.008 n=5+5)
SSA               7.91M ± 0%        7.91M ± 0%    ~     (all equal)
Flate              228k ± 0%         228k ± 0%  -0.05%  (p=0.008 n=5+5)
GoParser           283k ± 0%         283k ± 0%    ~     (all equal)
Reflect            952k ± 0%         952k ± 0%  -0.06%  (p=0.008 n=5+5)
Tar                188k ± 0%         188k ± 0%  -0.09%  (p=0.008 n=5+5)
XML                406k ± 0%         406k ± 0%  -0.02%  (p=0.008 n=5+5)
[Geo mean]         649k              648k       -0.04%

Fixes #18872

Change-Id: Ifeed0f71f13849732999aa731cc2bf40c0f0e32a
Reviewed-on: https://go-review.googlesource.com/43154
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-05-11 18:28:40 +00:00
Josh Bleecher Snyder
dccc653aeb cmd/compile: avoid checkwidth of [...] arrays
Fixes #20333

Change-Id: I0653cc859076f146d8ea8f5bd55cb22b0b8d987f
Reviewed-on: https://go-review.googlesource.com/43290
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-11 18:18:55 +00:00
Tom Bergan
8f36668178 net/http: for http2, use the priority write scheduler by default
Updates #18318

Change-Id: Ibd4ebc7708abf87eded8da9661378b5777b8a400
Reviewed-on: https://go-review.googlesource.com/43231
Run-TryBot: Tom Bergan <tombergan@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-11 17:46:43 +00:00
Ben Shi
6897030fe3 cmd/internal/obj: continue to optimize ARM's constant pool
Both Keith's https://go-review.googlesource.com/c/41612/ and
and Ben's https://go-review.googlesource.com/c/41679/ optimized ARM's
constant pool. But neither was complete.

First, BIC was forgotten.
1. "BIC $0xff00ff00, Reg" can be optimized to
   "BIC $0xff000000, Reg
    BIC $0x0000ff00, Reg"
2. "BIC $0xffff00ff, Reg" can be optimized to
   "AND $0x0000ff00, Reg"
3. "AND $0xffff00ff, Reg" can be optimized to
   "BIC $0x0000ff00, Reg"

Second, break a non-ARMImmRot to the subtraction of two ARMImmRots was
left as TODO.
1. "ADD $0x00fffff0, Reg" can be optimized to
   "ADD $0x01000000, Reg
    SUB $0x00000010, Reg"
2. "SUB $0x00fffff0, Reg" can be optimized to
   "SUB $0x01000000, Reg
    ADD $0x00000010, Reg"

This patch fixes them and issue #19844.

The go1 benchmark shows improvements.

name                     old time/op    new time/op    delta
BinaryTree17-4              41.4s ± 1%     41.7s ± 1%  +0.54%  (p=0.000 n=50+49)
Fannkuch11-4                24.7s ± 1%     25.1s ± 0%  +1.70%  (p=0.000 n=50+49)
FmtFprintfEmpty-4           853ns ± 1%     852ns ± 1%    ~     (p=0.833 n=50+50)
FmtFprintfString-4         1.33µs ± 1%    1.33µs ± 1%    ~     (p=0.163 n=50+50)
FmtFprintfInt-4            1.40µs ± 1%    1.40µs ± 0%    ~     (p=0.293 n=50+35)
FmtFprintfIntInt-4         2.09µs ± 1%    2.08µs ± 1%  -0.39%  (p=0.000 n=50+49)
FmtFprintfPrefixedInt-4    2.43µs ± 1%    2.43µs ± 1%    ~     (p=0.552 n=50+50)
FmtFprintfFloat-4          4.57µs ± 1%    4.42µs ± 1%  -3.18%  (p=0.000 n=50+50)
FmtManyArgs-4              8.62µs ± 1%    8.52µs ± 0%  -1.08%  (p=0.000 n=50+50)
GobDecode-4                 101ms ± 1%     101ms ± 2%  +0.45%  (p=0.001 n=49+49)
GobEncode-4                90.7ms ± 1%    91.1ms ± 2%  +0.51%  (p=0.001 n=50+50)
Gzip-4                      4.23s ± 1%     4.21s ± 1%  -0.62%  (p=0.000 n=50+50)
Gunzip-4                    623ms ± 1%     619ms ± 0%  -0.63%  (p=0.000 n=50+42)
HTTPClientServer-4          721µs ± 5%     683µs ± 3%  -5.25%  (p=0.000 n=50+47)
JSONEncode-4                251ms ± 1%     253ms ± 1%  +0.54%  (p=0.000 n=49+50)
JSONDecode-4                941ms ± 1%     944ms ± 1%  +0.30%  (p=0.001 n=49+50)
Mandelbrot200-4            49.3ms ± 1%    49.3ms ± 0%    ~     (p=0.918 n=50+48)
GoParse-4                  47.1ms ± 1%    47.2ms ± 1%  +0.18%  (p=0.025 n=50+50)
RegexpMatchEasy0_32-4      1.23µs ± 1%    1.24µs ± 1%  +0.30%  (p=0.000 n=49+50)
RegexpMatchEasy0_1K-4      7.74µs ± 7%    7.76µs ± 5%    ~     (p=0.888 n=50+50)
RegexpMatchEasy1_32-4      1.32µs ± 1%    1.32µs ± 1%  +0.23%  (p=0.003 n=50+50)
RegexpMatchEasy1_1K-4      10.6µs ± 2%    10.5µs ± 3%  -1.29%  (p=0.000 n=49+50)
RegexpMatchMedium_32-4     2.19µs ± 1%    2.10µs ± 1%  -3.79%  (p=0.000 n=49+49)
RegexpMatchMedium_1K-4      544µs ± 0%     545µs ± 0%    ~     (p=0.123 n=41+50)
RegexpMatchHard_32-4       28.8µs ± 0%    28.8µs ± 1%    ~     (p=0.580 n=46+50)
RegexpMatchHard_1K-4        863µs ± 1%     865µs ± 1%  +0.31%  (p=0.027 n=47+50)
Revcomp-4                  82.2ms ± 2%    82.3ms ± 2%    ~     (p=0.894 n=48+49)
Template-4                  1.06s ± 1%     1.04s ± 1%  -1.18%  (p=0.000 n=50+49)
TimeParse-4                7.25µs ± 1%    7.35µs ± 0%  +1.48%  (p=0.000 n=50+50)
TimeFormat-4               13.3µs ± 1%    13.2µs ± 1%  -0.13%  (p=0.007 n=50+50)
[Geo mean]                  736µs          733µs       -0.37%

name                     old speed      new speed      delta
GobDecode-4              7.60MB/s ± 1%  7.56MB/s ± 2%  -0.46%  (p=0.001 n=49+49)
GobEncode-4              8.47MB/s ± 1%  8.42MB/s ± 2%  -0.50%  (p=0.001 n=50+50)
Gzip-4                   4.58MB/s ± 1%  4.61MB/s ± 1%  +0.59%  (p=0.000 n=50+50)
Gunzip-4                 31.2MB/s ± 1%  31.4MB/s ± 0%  +0.63%  (p=0.000 n=50+42)
JSONEncode-4             7.73MB/s ± 1%  7.69MB/s ± 1%  -0.53%  (p=0.000 n=49+50)
JSONDecode-4             2.06MB/s ± 1%  2.06MB/s ± 1%    ~     (p=0.052 n=44+50)
GoParse-4                1.23MB/s ± 0%  1.23MB/s ± 2%    ~     (p=0.526 n=26+50)
RegexpMatchEasy0_32-4    25.9MB/s ± 1%  25.9MB/s ± 1%  -0.30%  (p=0.000 n=49+50)
RegexpMatchEasy0_1K-4     132MB/s ± 7%   132MB/s ± 6%    ~     (p=0.885 n=50+50)
RegexpMatchEasy1_32-4    24.2MB/s ± 1%  24.1MB/s ± 1%  -0.22%  (p=0.003 n=50+50)
RegexpMatchEasy1_1K-4    96.4MB/s ± 2%  97.8MB/s ± 3%  +1.36%  (p=0.000 n=50+50)
RegexpMatchMedium_32-4    460kB/s ± 0%   476kB/s ± 1%  +3.43%  (p=0.000 n=49+50)
RegexpMatchMedium_1K-4   1.88MB/s ± 0%  1.88MB/s ± 0%    ~     (all equal)
RegexpMatchHard_32-4     1.11MB/s ± 0%  1.11MB/s ± 1%  +0.34%  (p=0.000 n=45+50)
RegexpMatchHard_1K-4     1.19MB/s ± 1%  1.18MB/s ± 1%  -0.34%  (p=0.033 n=50+50)
Revcomp-4                30.9MB/s ± 2%  30.9MB/s ± 2%    ~     (p=0.894 n=48+49)
Template-4               1.84MB/s ± 1%  1.86MB/s ± 2%  +1.19%  (p=0.000 n=48+50)
[Geo mean]               6.63MB/s       6.65MB/s       +0.26%


Fixes #19844.

Change-Id: I5ad16cc0b29267bb4579aca3dcc10a0b8ade1aa4
Reviewed-on: https://go-review.googlesource.com/42430
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-05-11 13:53:54 +00:00
Daniel Martí
19b05acd13 reflect: remove dead v.typ assignment
v is not a pointer receiver, and v.typ isn't used in the lines below.
The assignment is dead. Remove it.

Keep the comment, as it refers to the whole case block and not just the
removed line.

Change-Id: Icb2d20c287d9a41bf620ebe5cdec764cd84178a7
Reviewed-on: https://go-review.googlesource.com/43134
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-11 08:07:21 +00:00
Ian Lance Taylor
c061f51e72 os: remove extraneous 's' from TestStdPipe error message
Change-Id: I73674a90d88da630b09dcb75ced5d9f0d96c3c09
Reviewed-on: https://go-review.googlesource.com/43153
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-10 20:19:50 +00:00
David Chase
643be70045 cmd/compile: repair copy-pasted method comment
Inadvertent copy-pasta in CL
https://go-review.googlesource.com/c/36207/

Is this allowed for 1.9 post-freeze?

Change-Id: I00dd27f9f53babeded3695346986a7a491f8a771
Reviewed-on: https://go-review.googlesource.com/43092
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-10 19:30:42 +00:00
Martin Möhrmann
aeee34cb24 runtime: remove unused cpuid_X variables
They are not exported and not used in the compiler or standard library.

Change-Id: Ie1d210464f826742d282f12258ed1792cbd2d188
Reviewed-on: https://go-review.googlesource.com/43135
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-10 19:28:42 +00:00
Josh Bleecher Snyder
201fd16568 cmd/link: set Fieldtrack symbol type to SDATA
Fixes #20316

Change-Id: I2553ad9a82dfcb30f020c2a3e37b868111425a20
Reviewed-on: https://go-review.googlesource.com/43151
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-10 19:24:29 +00:00
David Chase
00263a8968 cmd/compile: reduce debugger-worsening line number churn
Reuse block head or preceding instruction's line number for
register allocator's spill, fill, copy, rematerialization
instructionsl; and also for phi, and for no-src-pos
instructions.  Assembler creates same line number tables
for copy-predecessor-line and for no-src-pos,
but copy-predecessor produces better-looking assembly
language output with -S and with GOSSAFUNC, and does not
require changes to tests of existing assembly language.

Split "copyInto" into two cases, one for register allocation,
one for otherwise.  This caused the test score line change
count to increase by one, which may reflect legitimately
useful information preserved.  Without any special treatment
for copyInto, the change count increases by 21 more, from
51 to 72 (i.e., quite a lot).

There is a test; using two naive "scores" for line number
churn, the old numbering is 2x or 4x worse.

Fixes #18902.

Change-Id: I0a0a69659d30ee4e5d10116a0dd2b8c5df8457b1
Reviewed-on: https://go-review.googlesource.com/36207
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-10 17:16:44 +00:00
Hiroshi Ioka
1df777f6a4 go/build: accept spaces in cgo directives
Fixes #7906

Change-Id: Ibcf9cd670593241921ab3c426ff7357f799ebc3e
Reviewed-on: https://go-review.googlesource.com/43072
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-10 17:14:57 +00:00
Martin Möhrmann
69972aea74 internal/cpu: new package to detect cpu features
Implements detection of x86 cpu features that
are used in the go standard library.

Changes all standard library packages to use the new cpu package
instead of using runtime internal variables to check x86 cpu features.

Updates: #15403

Change-Id: I2999a10cb4d9ec4863ffbed72f4e021a1dbc4bb9
Reviewed-on: https://go-review.googlesource.com/41476
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-10 17:02:21 +00:00
Michael Munday
4fc498d89a cmd/compile: add generic rules to eliminate some unnecessary stores
Eliminates stores of values that have just been loaded from the same
location. Handles the common case where there are up to 3 intermediate
stores to non-overlapping struct fields.

For example the loads and stores of x.a, x.b and x.d in the following
function are now removed:

type T struct {
	a, b, c, d int
}

func f(x *T) {
	y := *x
	y.c += 8
	*x = y
}

Before this CL (s390x):

TEXT    "".f(SB)
	MOVD    "".x(R15), R5
	MOVD    (R5), R1
	MOVD    8(R5), R2
	MOVD    16(R5), R0
	MOVD    24(R5), R4
	ADD     $8, R0, R3
	STMG    R1, R4, (R5)
	RET

After this CL (s390x):

TEXT	"".f(SB)
	MOVD	"".x(R15), R1
	MOVD	16(R1), R0
	ADD	$8, R0, R0
	MOVD	R0, 16(R1)
	RET

In total these rules are triggered ~5091 times during all.bash,
which is broken down as:

Intermediate stores | Triggered
--------------------+----------
0                   | 1434
1                   | 2508
2                   | 888
3                   | 261
--------------------+----------

Change-Id: Ia4721ae40146aceec1fdd3e65b0e9283770bfba5
Reviewed-on: https://go-review.googlesource.com/38793
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-10 15:58:43 +00:00
Michael Munday
cb83924d5b cmd/compile/internal/ssa: fix generation of ppc64x rules
The files PPC64.rules and rewritePPC64.go were out of sync due to
conflicts between CL 41630 and CL 42145 (i.e. running 'go run *.go'
in the gen directory resulted in unexpected changes).

Change-Id: I1d409656b66afeab6cb9c6df9b3dcab7859caa75
Reviewed-on: https://go-review.googlesource.com/43091
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
2017-05-10 15:32:12 +00:00
David Chase
41d0bbdc16 cmd/link: include DW_AT_producer in .debug_info
This can make life easier for Delve (and other debuggers),
and can help them with bug reports.

Sample producer field (from objdump):
<48> DW_AT_producer : Go cmd/compile devel +8a59dbf41a Mon May 8 16:02:44 2017 -0400

Change-Id: I0605843c959b53a60a25a3b870aa8755bf5d5b13
Reviewed-on: https://go-review.googlesource.com/33588
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-05-10 14:47:41 +00:00
Daniel Martí
9bced47706 reflect: don't panic in ArrayOf if elem size is 0
We do a division by the elem type size to check if the array size would
be too large for the virtual address space. This is a silly check if the
size is 0, but the problem is that it means a division by zero and a
panic.

Since arrays of empty structs are valid in a regular program, make them
also work in reflect.

Use a separate, explicit test with struct{}{} to make sure the test for
a zero-sized type is not confused with the rest.

Fixes #20313.

Change-Id: I47b8b87e6541631280b79227bdea6a0f6035c9e0
Reviewed-on: https://go-review.googlesource.com/43131
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-10 13:44:53 +00:00
Lynn Boger
8304d10763 cmd/compile: ppc64x intrinsics for math/bits
This adds math/bits intrinsics for OnesCount, Len, TrailingZeros on
ppc64x.

benchmark                       old ns/op     new ns/op     delta
BenchmarkLeadingZeros-16        4.26          1.71          -59.86%
BenchmarkLeadingZeros16-16      3.04          1.83          -39.80%
BenchmarkLeadingZeros32-16      3.31          1.82          -45.02%
BenchmarkLeadingZeros64-16      3.69          1.71          -53.66%
BenchmarkTrailingZeros-16       2.55          1.62          -36.47%
BenchmarkTrailingZeros32-16     2.55          1.77          -30.59%
BenchmarkTrailingZeros64-16     2.78          1.62          -41.73%
BenchmarkOnesCount-16           3.19          0.93          -70.85%
BenchmarkOnesCount32-16         2.55          1.18          -53.73%
BenchmarkOnesCount64-16         3.22          0.93          -71.12%

Update #18616

I also made a change to bits_test.go because when debugging some failures
the output was not quite providing the right argument information.

Change-Id: Ia58d31d1777cf4582a4505f85b11a1202ca07d3e
Reviewed-on: https://go-review.googlesource.com/41630
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-10 12:10:56 +00:00
Daniel Martí
a4864094f0 reflect: fix String of new array types
When constructing a new type for an array type in ArrayOf, we don't
reset tflag to 0. All the other methods in the package, such as SliceOf,
do this already. This results in the new array type having weird issues
when being printed, such as having tflagExtraStar set when it shouldn't.

That flag removes the first char to get rid of '*', but when used
incorrectly in this case it eats the '[' character leading to broken
strings like "3]int".

This was fixed in 56752eb2 for issue #16722, but ArrayOf was missed.

Also make the XM test struct have a non-zero size as that leads to a
division by zero panic in ArrayOf.

Fixes #20311.

Change-Id: I18f1027fdbe9f71767201e7424269c3ceeb23eb5
Reviewed-on: https://go-review.googlesource.com/43130
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-10 11:42:46 +00:00
Marvin Stenger
266a3b66ca cmd/compile/internal/gc: rename signatlist to signatset
Also change type from map[*types.Type]bool to map[*types.Type]struct{}.
This is basically a clean-up.

Change-Id: I167583eff0fa1070a7522647219476033b52b840
Reviewed-on: https://go-review.googlesource.com/41859
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-10 01:47:54 +00:00
Josh Bleecher Snyder
1213776650 cmd/compile: use a buffered channel for the function queue
Updates #20307

With -c=2:

name        old time/op       new time/op       delta
Template          140ms ± 3%        139ms ± 4%  -1.06%  (p=0.003 n=50+50)
Unicode          81.1ms ± 4%       81.9ms ± 4%  +0.96%  (p=0.006 n=50+49)
GoTypes           375ms ± 3%        374ms ± 3%    ~     (p=0.094 n=48+48)
Compiler          1.69s ± 2%        1.68s ± 2%  -0.41%  (p=0.004 n=49+48)
SSA               3.05s ± 1%        3.05s ± 2%    ~     (p=0.953 n=47+49)
Flate            86.3ms ± 2%       85.9ms ± 2%  -0.49%  (p=0.011 n=49+48)
GoParser         99.5ms ± 3%       99.3ms ± 3%    ~     (p=0.394 n=48+49)
Reflect           262ms ± 3%        261ms ± 3%    ~     (p=0.354 n=47+49)
Tar              81.4ms ± 3%       79.7ms ± 4%  -1.98%  (p=0.000 n=47+50)
XML               133ms ± 3%        133ms ± 3%    ~     (p=0.992 n=50+49)
[Geo mean]        236ms             235ms       -0.36%

name        old user-time/op  new user-time/op  delta
Template          249ms ± 5%        242ms ± 7%  -2.61%  (p=0.000 n=48+50)
Unicode           111ms ± 4%        111ms ± 6%    ~     (p=0.407 n=46+47)
GoTypes           753ms ± 2%        748ms ± 3%  -0.65%  (p=0.010 n=48+50)
Compiler          3.28s ± 2%        3.27s ± 2%  -0.40%  (p=0.026 n=49+47)
SSA               7.03s ± 2%        7.01s ± 3%    ~     (p=0.154 n=45+50)
Flate             154ms ± 3%        154ms ± 3%    ~     (p=0.306 n=49+49)
GoParser          180ms ± 4%        179ms ± 4%    ~     (p=0.148 n=48+48)
Reflect           427ms ± 2%        428ms ± 3%    ~     (p=0.502 n=46+49)
Tar               142ms ± 5%        135ms ± 9%  -4.83%  (p=0.000 n=46+50)
XML               247ms ± 3%        247ms ± 4%    ~     (p=0.921 n=49+49)
[Geo mean]        426ms             422ms       -0.92%


Change-Id: I4746234439ddb9a7e5840fc783b8857da6a4a680
Reviewed-on: https://go-review.googlesource.com/43110
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-10 01:44:12 +00:00
Josh Bleecher Snyder
94a017f3f5 cmd/compile: allow OpVarXXX calls to be duplicated in writebarrier blocks
OpVarXXX Values don't generate instructions,
so there's no reason not to duplicate them,
and duplicating them generates better code
(fewer branches).

This requires changing the start/end accounting
to correctly handle the case in which we have run
of Values beginning with an OpVarXXX, e.g.
OpVarDef, OpZeroWB, OpMoveWB.
In that case, the sequence of values should begin
at the OpZeroWB, not the OpVarDef.

This also lays the groundwork for experimenting
with allowing duplication of some scalar stores.

Shrinks function text sizes a tiny amount:

name        old object-bytes  new object-bytes  delta
Template           381k ± 0%         381k ± 0%  -0.01%  (p=0.008 n=5+5)
Unicode            203k ± 0%         203k ± 0%  -0.04%  (p=0.008 n=5+5)
GoTypes           1.17M ± 0%        1.17M ± 0%  -0.01%  (p=0.008 n=5+5)
SSA               8.24M ± 0%        8.24M ± 0%  -0.00%  (p=0.008 n=5+5)
Flate              230k ± 0%         230k ± 0%    ~     (all equal)
GoParser           286k ± 0%         286k ± 0%    ~     (all equal)
Reflect           1.00M ± 0%        1.00M ± 0%    ~     (all equal)
Tar                189k ± 0%         189k ± 0%    ~     (all equal)
XML                415k ± 0%         415k ± 0%  -0.01%  (p=0.008 n=5+5)

Updates #19838

Change-Id: Ic5ef30855919f1468066eba08ae5c4bd9a01db27
Reviewed-on: https://go-review.googlesource.com/42011
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2017-05-09 23:54:14 +00:00
Ian Lance Taylor
5331e7e9df cmd/internal/obj, cmd/link: fix st_other field on PPC64
In PPC64 ELF files, the st_other field indicates the number of
prologue instructions between the global and local entry points.
We add the instructions in the compiler and assembler if -shared is used.
We were assuming that the instructions were present when building a
c-archive or PIE or doing dynamic linking, on the assumption that those
are the cases where the go tool would be building with -shared.
That assumption fails when using some other tool, such as Bazel,
that does not necessarily use -shared in exactly the same way.

This CL records in the object file whether a symbol was compiled
with -shared (this will be the same for all symbols in a given compilation)
and uses that information when setting the st_other field.

Fixes #20290.

Change-Id: Ib2b77e16aef38824871102e3c244fcf04a86c6ea
Reviewed-on: https://go-review.googlesource.com/43051
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-05-09 23:36:51 +00:00
Todd Neal
08dca4c649 cmd/compile: ignore types when considering tuple select for CSE
Fixes #20097

Change-Id: I3c9626ccc8cd0c46a7081ea8650b2ff07a5d4fcd
Reviewed-on: https://go-review.googlesource.com/41505
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-09 23:22:00 +00:00
Josh Bleecher Snyder
46b88c9fbc cmd/compile: change ssa.Type into *types.Type
When package ssa was created, Type was in package gc.
To avoid circular dependencies, we used an interface (ssa.Type)
to represent type information in SSA.

In the Go 1.9 cycle, gri extricated the Type type from package gc.
As a result, we can now use it in package ssa.
Now, instead of package types depending on package ssa,
it is the other way.
This is a more sensible dependency tree,
and helps compiler performance a bit.

Though this is a big CL, most of the changes are
mechanical and uninteresting.

Interesting bits:

* Add new singleton globals to package types for the special
  SSA types Memory, Void, Invalid, Flags, and Int128.
* Add two new Types, TSSA for the special types,
  and TTUPLE, for SSA tuple types.
  ssa.MakeTuple is now types.NewTuple.
* Move type comparison result constants CMPlt, CMPeq, and CMPgt
  to package types.
* We had picked the name "types" in our rules for the handy
  list of types provided by ssa.Config. That conflicted with
  the types package name, so change it to "typ".
* Update the type comparison routine to handle tuples and special
  types inline.
* Teach gc/fmt.go how to print special types.
* We can now eliminate ElemTypes in favor of just Elem,
  and probably also some other duplicated Type methods
  designed to return ssa.Type instead of *types.Type.
* The ssa tests were using their own dummy types,
  and they were not particularly careful about types in general.
  Of necessity, this CL switches them to use *types.Type;
  it does not make them more type-accurate.
  Unfortunately, using types.Type means initializing a bit
  of the types universe.
  This is prime for refactoring and improvement.

This shrinks ssa.Value; it now fits in a smaller size class
on 64 bit systems. This doesn't have a giant impact,
though, since most Values are preallocated in a chunk.

name        old alloc/op      new alloc/op      delta
Template         37.9MB ± 0%       37.7MB ± 0%  -0.57%  (p=0.000 n=10+8)
Unicode          28.9MB ± 0%       28.7MB ± 0%  -0.52%  (p=0.000 n=10+10)
GoTypes           110MB ± 0%        109MB ± 0%  -0.88%  (p=0.000 n=10+10)
Flate            24.7MB ± 0%       24.6MB ± 0%  -0.66%  (p=0.000 n=10+10)
GoParser         31.1MB ± 0%       30.9MB ± 0%  -0.61%  (p=0.000 n=10+9)
Reflect          73.9MB ± 0%       73.4MB ± 0%  -0.62%  (p=0.000 n=10+8)
Tar              25.8MB ± 0%       25.6MB ± 0%  -0.77%  (p=0.000 n=9+10)
XML              41.2MB ± 0%       40.9MB ± 0%  -0.80%  (p=0.000 n=10+10)
[Geo mean]       40.5MB            40.3MB       -0.68%

name        old allocs/op     new allocs/op     delta
Template           385k ± 0%         386k ± 0%    ~     (p=0.356 n=10+9)
Unicode            343k ± 1%         344k ± 0%    ~     (p=0.481 n=10+10)
GoTypes           1.16M ± 0%        1.16M ± 0%  -0.16%  (p=0.004 n=10+10)
Flate              238k ± 1%         238k ± 1%    ~     (p=0.853 n=10+10)
GoParser           320k ± 0%         320k ± 0%    ~     (p=0.720 n=10+9)
Reflect            957k ± 0%         957k ± 0%    ~     (p=0.460 n=10+8)
Tar                252k ± 0%         252k ± 0%    ~     (p=0.133 n=9+10)
XML                400k ± 0%         400k ± 0%    ~     (p=0.796 n=10+10)
[Geo mean]         428k              428k       -0.01%


Removing all the interface calls helps non-trivially with CPU, though.

name        old time/op       new time/op       delta
Template          178ms ± 4%        173ms ± 3%  -2.90%  (p=0.000 n=94+96)
Unicode          85.0ms ± 4%       83.9ms ± 4%  -1.23%  (p=0.000 n=96+96)
GoTypes           543ms ± 3%        528ms ± 3%  -2.73%  (p=0.000 n=98+96)
Flate             116ms ± 3%        113ms ± 4%  -2.34%  (p=0.000 n=96+99)
GoParser          144ms ± 3%        140ms ± 4%  -2.80%  (p=0.000 n=99+97)
Reflect           344ms ± 3%        334ms ± 4%  -3.02%  (p=0.000 n=100+99)
Tar               106ms ± 5%        103ms ± 4%  -3.30%  (p=0.000 n=98+94)
XML               198ms ± 5%        192ms ± 4%  -2.88%  (p=0.000 n=92+95)
[Geo mean]        178ms             173ms       -2.65%

name        old user-time/op  new user-time/op  delta
Template          229ms ± 5%        224ms ± 5%  -2.36%  (p=0.000 n=95+99)
Unicode           107ms ± 6%        106ms ± 5%  -1.13%  (p=0.001 n=93+95)
GoTypes           696ms ± 4%        679ms ± 4%  -2.45%  (p=0.000 n=97+99)
Flate             137ms ± 4%        134ms ± 5%  -2.66%  (p=0.000 n=99+96)
GoParser          176ms ± 5%        172ms ± 8%  -2.27%  (p=0.000 n=98+100)
Reflect           430ms ± 6%        411ms ± 5%  -4.46%  (p=0.000 n=100+92)
Tar               128ms ±13%        123ms ±13%  -4.21%  (p=0.000 n=100+100)
XML               239ms ± 6%        233ms ± 6%  -2.50%  (p=0.000 n=95+97)
[Geo mean]        220ms             213ms       -2.76%


Change-Id: I15c7d6268347f8358e75066dfdbd77db24e8d0c1
Reviewed-on: https://go-review.googlesource.com/42145
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-09 23:01:51 +00:00
Josh Bleecher Snyder
6a24b2d0c1 cmd/compile: add boolean simplification rules
These collectively fire a few hundred times during make.bash,
mostly rewriting XOR SETNE -> SETEQ.

Fixes #17905.

Change-Id: Ic5eb241ee93ed67099da3de11f59e4df9fab64a3
Reviewed-on: https://go-review.googlesource.com/42491
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-09 21:50:55 +00:00
Marvin Stenger
9aeced650f cmd/compile/internal/ssa: mark boolean instructions commutative
Mark AndB, OrB, EqB, and NeqB as commutative.

Change-Id: Ife7cfcb9780cc5dd669617cb52339ab336667da4
Reviewed-on: https://go-review.googlesource.com/42515
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-09 21:31:38 +00:00
Josh Bleecher Snyder
6f2ee0f3df cmd/compile: make builds reproducible in presence of **byte and **int8
CL 39915 introduced sorting of signats by ShortString
for reproducible builds. But ShortString treats types
byte and uint8 identically; same for rune and uint32.
CL 39915 attempted to compensate for this by only
adding the underlying type (uint8) to signats in addsignat.

This only works for byte and uint8. For e.g. *byte and *uint,
both get added, and their sort order is random,
leading to non-reproducible builds.

One fix would be to add yet another type printing mode
that doesn't eliminate byte and rune, and use it
for sorting signats. But the formatting routines
are complicated enough as it is.

Instead, just sort first by ShortString and then by String.
We can't just use String, because ShortString makes distinctions
that String doesn't. ShortString is really preferred here;
String is serving only as a backstop for handling of bytes and runes.

The long series of types in the test helps increase the odds of
failure, allowing a smaller number of iterations in the test.
On my machine, a full test takes 700ms.

Passes toolstash-check.

Updates #19961
Fixes #20272

name        old alloc/op      new alloc/op      delta
Template         37.9MB ± 0%       37.9MB ± 0%  +0.12%  (p=0.032 n=5+5)
Unicode          28.9MB ± 0%       28.9MB ± 0%    ~     (p=0.841 n=5+5)
GoTypes           110MB ± 0%        110MB ± 0%    ~     (p=0.841 n=5+5)
Compiler          463MB ± 0%        463MB ± 0%    ~     (p=0.056 n=5+5)
SSA              1.11GB ± 0%       1.11GB ± 0%  +0.02%  (p=0.016 n=5+5)
Flate            24.7MB ± 0%       24.8MB ± 0%  +0.14%  (p=0.032 n=5+5)
GoParser         31.1MB ± 0%       31.1MB ± 0%    ~     (p=0.421 n=5+5)
Reflect          73.9MB ± 0%       73.9MB ± 0%    ~     (p=1.000 n=5+5)
Tar              25.8MB ± 0%       25.8MB ± 0%  +0.15%  (p=0.016 n=5+5)
XML              41.2MB ± 0%       41.2MB ± 0%    ~     (p=0.310 n=5+5)
[Geo mean]       72.0MB            72.0MB       +0.07%

name        old allocs/op     new allocs/op     delta
Template           384k ± 0%         385k ± 1%    ~     (p=0.056 n=5+5)
Unicode            343k ± 0%         344k ± 0%    ~     (p=0.548 n=5+5)
GoTypes           1.16M ± 0%        1.16M ± 0%    ~     (p=0.421 n=5+5)
Compiler          4.43M ± 0%        4.44M ± 0%  +0.26%  (p=0.032 n=5+5)
SSA               9.86M ± 0%        9.87M ± 0%  +0.10%  (p=0.032 n=5+5)
Flate              237k ± 1%         238k ± 0%  +0.49%  (p=0.032 n=5+5)
GoParser           319k ± 1%         320k ± 1%    ~     (p=0.151 n=5+5)
Reflect            957k ± 0%         957k ± 0%    ~     (p=1.000 n=5+5)
Tar                251k ± 0%         252k ± 1%  +0.49%  (p=0.016 n=5+5)
XML                399k ± 0%         401k ± 1%    ~     (p=0.310 n=5+5)
[Geo mean]         739k              741k       +0.26%

Change-Id: Ic27995a8d374d012b8aca14546b1df9d28d30df7
Reviewed-on: https://go-review.googlesource.com/42955
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-05-09 21:15:12 +00:00
Josh Bleecher Snyder
9fda4df9a0 cmd/compile: make "imported and not used" errors deterministic
If there were more unused imports than
the maximum default number of errors to report,
the set of reported imports was non-deterministic.

Fix by accumulating and sorting them prior to output.

Fixes #20298

Change-Id: Ib3d5a15fd7dc40009523fcdc1b93ddc62a1b05f2
Reviewed-on: https://go-review.googlesource.com/42954
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-05-09 21:14:56 +00:00
Cherry Zhang
fb0ccc5d0a cmd/internal/obj/arm64, cmd/compile: improve offset folding on ARM64
ARM64 assembler backend only accepts loads and stores with small
or aligned offset. The compiler therefore can only fold small or
aligned offsets into loads and stores. For locals and args, their
offsets to SP are not known until very late, and the compiler
makes conservative decision not folding some of them. However,
in most cases, the offset is indeed small or aligned, and can
be folded into load and store (but actually not).

This CL adds support of loads and stores with large and unaligned
offsets. When the offset doesn't fit into the instruction, it
uses two instructions and (for very large offset) the constant
pool. This way, the compiler doesn't need to be conservative,
and can simply fold the offset.

To make it work, the assembler's optab matching rules need to be
changed. Before, MOVD accepts C_UAUTO32K which matches multiple
of 8 between 0 and 32K, and also C_UAUTO16K, which may not be
multiple of 8 and does not fit into MOVD instruction. The
assembler errors in the latter case. This change makes it only
matches multiple of 8 (or offsets within ±256, which also fits
in instruction), and uses the large-or-unaligned-offset rule
for things doesn't fit (without error). Other sized move rules
are changed similarly.

Class C_UAUTO64K and C_UOREG64K are removed, as they are never
used.

In shared library, load/store of global is rewritten to using
GOT and temp register, which conflicts with the use of temp
register for assembling large offset. So the folding is disabled
for globals in shared library mode.

Reduce cmd/go binary size by 2%.

name                     old time/op    new time/op    delta
BinaryTree17-8              8.67s ± 0%     8.61s ± 0%   -0.60%  (p=0.000 n=9+10)
Fannkuch11-8                6.24s ± 0%     6.19s ± 0%   -0.83%  (p=0.000 n=10+9)
FmtFprintfEmpty-8           116ns ± 0%     116ns ± 0%     ~     (all equal)
FmtFprintfString-8          196ns ± 0%     192ns ± 0%   -1.89%  (p=0.000 n=10+10)
FmtFprintfInt-8             199ns ± 0%     198ns ± 0%   -0.35%  (p=0.001 n=9+10)
FmtFprintfIntInt-8          294ns ± 0%     293ns ± 0%   -0.34%  (p=0.000 n=8+8)
FmtFprintfPrefixedInt-8     318ns ± 1%     318ns ± 1%     ~     (p=1.000 n=10+10)
FmtFprintfFloat-8           537ns ± 0%     531ns ± 0%   -1.17%  (p=0.000 n=9+10)
FmtManyArgs-8              1.19µs ± 1%    1.18µs ± 1%   -1.41%  (p=0.001 n=10+10)
GobDecode-8                17.2ms ± 1%    17.3ms ± 2%     ~     (p=0.165 n=10+10)
GobEncode-8                14.7ms ± 1%    14.7ms ± 2%     ~     (p=0.631 n=10+10)
Gzip-8                      837ms ± 0%     836ms ± 0%   -0.14%  (p=0.006 n=9+10)
Gunzip-8                    141ms ± 0%     139ms ± 0%   -1.24%  (p=0.000 n=9+10)
HTTPClientServer-8          256µs ± 1%     253µs ± 1%   -1.35%  (p=0.000 n=10+10)
JSONEncode-8               40.1ms ± 1%    41.3ms ± 1%   +3.06%  (p=0.000 n=10+9)
JSONDecode-8                157ms ± 1%     156ms ± 1%   -0.83%  (p=0.001 n=9+8)
Mandelbrot200-8            8.94ms ± 0%    8.94ms ± 0%   +0.02%  (p=0.000 n=9+9)
GoParse-8                  8.69ms ± 0%    8.54ms ± 1%   -1.69%  (p=0.000 n=8+10)
RegexpMatchEasy0_32-8       227ns ± 1%     228ns ± 1%   +0.48%  (p=0.016 n=10+9)
RegexpMatchEasy0_1K-8      1.92µs ± 0%    1.63µs ± 0%  -15.08%  (p=0.000 n=10+9)
RegexpMatchEasy1_32-8       256ns ± 0%     251ns ± 0%   -2.19%  (p=0.000 n=10+9)
RegexpMatchEasy1_1K-8      2.38µs ± 0%    2.09µs ± 0%  -12.49%  (p=0.000 n=10+9)
RegexpMatchMedium_32-8      352ns ± 0%     354ns ± 0%   +0.39%  (p=0.002 n=10+9)
RegexpMatchMedium_1K-8      106µs ± 0%     106µs ± 0%   -0.05%  (p=0.005 n=10+9)
RegexpMatchHard_32-8       5.92µs ± 0%    5.89µs ± 0%   -0.40%  (p=0.000 n=9+8)
RegexpMatchHard_1K-8        180µs ± 0%     179µs ± 0%   -0.14%  (p=0.000 n=10+9)
Revcomp-8                   1.20s ± 0%     1.13s ± 0%   -6.29%  (p=0.000 n=9+8)
Template-8                  159ms ± 1%     154ms ± 1%   -3.14%  (p=0.000 n=9+10)
TimeParse-8                 800ns ± 3%     769ns ± 1%   -3.91%  (p=0.000 n=10+10)
TimeFormat-8                826ns ± 2%     817ns ± 2%   -1.04%  (p=0.050 n=10+10)
[Geo mean]                  145µs          143µs        -1.79%

Change-Id: I5fc42087cee9b54ea414f8ef6d6d020b80eb5985
Reviewed-on: https://go-review.googlesource.com/42172
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
2017-05-09 19:41:00 +00:00
Josh Bleecher Snyder
5e0bcb3893 cmd/go: enable concurrent backend compilation by default
It can be disabled by setting the environment variable
GO19CONCURRENTCOMPILATION=0, or with -gcflags=-c=1.

Fixes #15756.

Change-Id: I7acbf16330512b62ee14ecbab1f46b53ec5a67b6
Reviewed-on: https://go-review.googlesource.com/41820
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2017-05-09 19:22:10 +00:00
Josh Bleecher Snyder
f4e5bd483b cmd/go: add support for concurrent backend compilation
It is disabled by default.
It can be enabled by setting the environment variable
GO19CONCURRENTCOMPILATION=1.

Benchmarking results are presented in a grid.
Columns are different values of c (compiler backend concurrency);
rows are different values of p (process concurrency).

'go build -a std cmd', a 4 core raspberry pi 3:

            c=1        c=2        c=4
StdCmd/p=1  504s ± 2%  413s ± 4%  367s ± 3%
StdCmd/p=2  314s ± 3%  266s ± 4%  267s ± 4%
StdCmd/p=4  254s ± 5%  241s ± 5%  238s ± 6%

'go build -a std cmd', an 8 core darwin/amd64 laptop:

            c=1         c=2         c=4         c=6         c=8
StdCmd/p=1  40.4s ± 7%  31.0s ± 1%  27.3s ± 1%  27.8s ± 0%  27.7s ± 0%
StdCmd/p=2  21.9s ± 1%  17.9s ± 1%  16.9s ± 1%  17.0s ± 1%  17.2s ± 0%
StdCmd/p=4  17.4s ± 2%  14.5s ± 2%  13.3s ± 2%  13.5s ± 2%  13.6s ± 2%
StdCmd/p=6  16.9s ± 1%  14.2s ± 2%  13.1s ± 2%  13.2s ± 2%  13.3s ± 2%
StdCmd/p=8  16.7s ± 2%  14.2s ± 2%  13.2s ± 3%  13.2s ± 2%  13.4s ± 2%

'go build -a std cmd', a 96 core arm64 server:

             c=1         c=2         c=4         c=6         c=8         c=16        c=32        c=64        c=96
StdCmd/p=1    173s ± 1%   133s ± 1%   114s ± 1%   109s ± 1%   106s ± 0%   106s ± 1%   107s ± 1%   110s ± 1%   113s ± 1%
StdCmd/p=2   94.2s ± 2%  71.5s ± 1%  61.7s ± 1%  58.7s ± 1%  57.5s ± 2%  56.9s ± 1%  58.0s ± 1%  59.6s ± 1%  61.0s ± 1%
StdCmd/p=4   74.1s ± 2%  53.5s ± 1%  43.7s ± 2%  40.5s ± 1%  39.2s ± 2%  38.9s ± 2%  39.5s ± 3%  40.3s ± 2%  40.8s ± 1%
StdCmd/p=6   69.3s ± 1%  50.2s ± 2%  40.3s ± 2%  37.3s ± 3%  36.0s ± 3%  35.3s ± 2%  36.0s ± 2%  36.8s ± 2%  37.5s ± 2%
StdCmd/p=8   66.1s ± 2%  47.7s ± 2%  38.6s ± 2%  35.7s ± 2%  34.4s ± 1%  33.6s ± 2%  34.2s ± 2%  34.6s ± 1%  35.0s ± 1%
StdCmd/p=16  63.4s ± 2%  45.3s ± 2%  36.3s ± 2%  33.3s ± 2%  32.0s ± 3%  31.6s ± 2%  32.1s ± 2%  32.5s ± 2%  32.7s ± 2%
StdCmd/p=32  62.2s ± 1%  44.2s ± 2%  35.3s ± 2%  32.4s ± 2%  31.2s ± 2%  30.9s ± 2%  31.1s ± 2%  31.7s ± 2%  32.0s ± 2%
StdCmd/p=64  62.2s ± 1%  44.3s ± 2%  35.4s ± 2%  32.4s ± 2%  31.2s ± 2%  30.9s ± 2%  31.2s ± 2%  31.8s ± 3%  32.2s ± 3%
StdCmd/p=96  62.2s ± 2%  44.4s ± 2%  35.3s ± 2%  32.3s ± 2%  31.1s ± 2%  30.9s ± 3%  31.3s ± 2%  31.7s ± 1%  32.1s ± 2%

benchjuju, an 8 core darwin/amd64 laptop:

               c=1         c=2         c=4         c=6         c=8
BuildJuju/p=1  55.3s ± 0%  46.3s ± 0%  41.9s ± 0%  41.4s ± 1%  41.3s ± 0%
BuildJuju/p=2  33.7s ± 1%  28.4s ± 1%  26.7s ± 1%  26.6s ± 1%  26.8s ± 1%
BuildJuju/p=4  24.7s ± 1%  22.3s ± 1%  21.4s ± 1%  21.7s ± 1%  21.8s ± 1%
BuildJuju/p=6  20.6s ± 1%  19.3s ± 2%  19.4s ± 1%  19.7s ± 1%  19.9s ± 1%
BuildJuju/p=8  20.6s ± 2%  19.5s ± 2%  19.3s ± 2%  19.6s ± 1%  19.8s ± 2%

Updates #15756

Change-Id: I8a56e88953071a05eee764002024c54cd888a56c
Reviewed-on: https://go-review.googlesource.com/41819
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-09 19:18:18 +00:00
Robert Griesemer
86f5f7fdfa spec: clarify unsafe.Pointer conversions
A pointer type of underlying type unsafe.Pointer can be used in
unsafe conversions. Document unfortunate status quo.

Fixes #19306.

Change-Id: I28172508a200561f8df366bbf2c2807ef3b48c97
Reviewed-on: https://go-review.googlesource.com/42132
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2017-05-09 18:35:13 +00:00
Ibrahim AshShohail
541029636a go/token: remove excess parenthesis in NoPos.IsValid() documentation
Fixes #20294

Change-Id: I32ac862fe00180210a04103cc94c4d9fef5d1b6c
Reviewed-on: https://go-review.googlesource.com/42992
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-09 15:05:14 +00:00
Austin Clements
d659682de2 runtime/pprof: deflake TestGoroutineCounts
TestGoroutineCounts currently depends on timing to get 100 goroutines
to a known blocking point before taking a profile. This fails
frequently, with different goroutines captured at different stacks.
The test is disabled on openbsd because it was too flaky, but in fact
it flakes on all platforms.

Fix this by using Gosched instead of timing. This is both much more
reliable and makes the test run faster.

Fixes #15156.

Change-Id: Ia6e894196d717655b8fb4ee96df53f6cc8bc5f1f
Reviewed-on: https://go-review.googlesource.com/42953
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-09 15:04:46 +00:00
Ian Lance Taylor
9eacd977a0 cmd/go: put user flags after code generation flag
This permits the user to override the code generation flag when they
know better. This is always a good policy for all flags automatically
inserted by the build system.

Doing this now so that I can write a test for #20290.

Update #20290

Change-Id: I5c6708a277238d571b8d037993a5a59e2a442e98
Reviewed-on: https://go-review.googlesource.com/42952
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-09 14:23:50 +00:00
Rob Phoenix
1e732ca388 net: fix ExampleParseCIDR IPv4 prefix length
Issue #15228 describes that reserved address blocks should be used for
documentation purposes. This change updates the prefix length so the
IPv4 address adheres to this.

Change-Id: I237d9cce1a71f4fd95f927ec894ce53fa806047f
Reviewed-on: https://go-review.googlesource.com/42991
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2017-05-09 13:47:33 +00:00
Alex Brainman
096e2bffdf cmd/go: run tests that require symlinks
Change-Id: I19a724ea4eb1ba0ff558721650c89a949e53b7c7
Reviewed-on: https://go-review.googlesource.com/42895
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-09 04:49:30 +00:00
Alex Brainman
6dcaa095c5 os: avoid calulating fileStat.path until it is needed
This CL improves

on my Windows 7

name         old time/op    new time/op    delta
Readdirname    58.1µs ± 1%    58.1µs ± 0%     ~     (p=0.817 n=8+8)
Readdir        58.0µs ± 3%    57.8µs ± 0%     ~     (p=0.944 n=9+8)

name         old alloc/op   new alloc/op   delta
Readdirname    3.03kB ± 0%    2.84kB ± 0%   -6.33%  (p=0.000 n=10+10)
Readdir        3.00kB ± 0%    2.81kB ± 0%   -6.40%  (p=0.000 n=10+10)

name         old allocs/op  new allocs/op  delta
Readdirname      34.0 ± 0%      30.0 ± 0%  -11.76%  (p=0.000 n=10+10)
Readdir          33.0 ± 0%      29.0 ± 0%  -12.12%  (p=0.000 n=10+10)

on my Windows XP

name           old time/op    new time/op    delta
Readdirname-2    85.5µs ± 0%    84.0µs ± 0%   -1.83%  (p=0.000 n=10+10)
Readdir-2        84.6µs ± 0%    83.5µs ± 0%   -1.31%  (p=0.000 n=10+9)

name           old alloc/op   new alloc/op   delta
Readdirname-2    6.52kB ± 0%    5.66kB ± 0%  -13.25%  (p=0.000 n=10+10)
Readdir-2        6.39kB ± 0%    5.53kB ± 0%  -13.52%  (p=0.000 n=10+10)

name           old allocs/op  new allocs/op  delta
Readdirname-2      78.0 ± 0%      66.0 ± 0%  -15.38%  (p=0.000 n=10+10)
Readdir-2          77.0 ± 0%      65.0 ± 0%  -15.58%  (p=0.000 n=10+10)

Change-Id: I5d698eca86b8e94a46b6cfbd5947898b7b3fbdbd
Reviewed-on: https://go-review.googlesource.com/42894
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-09 04:47:47 +00:00
ltnwgl
f5352a7763 container/heap: optimization when selecting smaller child
In down(), if two children are equal, we can choose either one.
Inspired by https://codereview.appspot.com/6613064/

Change-Id: Iaad4ca5e2f5111bf3abb87f606584e7d274c620b
Reviewed-on: https://go-review.googlesource.com/38612
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2017-05-09 03:38:37 +00:00
Rob Phoenix
716761b8b1 net: add examples for IPv4, ParseCIDR & IPv4Mask
Further examples to support the net package.

See issue #5757

Change-Id: I839fd97a468c8d9195e8f4a0ee886ba50ca3f382
Reviewed-on: https://go-review.googlesource.com/42912
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-09 00:34:38 +00:00
Robert Griesemer
bcf2d74ce8 cmd/compile: better errors for float constants with large exponents
Also: Removed misleading comment.

Fixes #20232.

Change-Id: I0b141b1360ac53267b7ebfcec7a2e2a238f3f46c
Reviewed-on: https://go-review.googlesource.com/42930
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2017-05-08 22:56:10 +00:00
Bill O'Farrell
88672de7af math: use SIMD to accelerate additional scalar math functions on s390x
As necessary, math functions were structured to use stubs, so that they can
be accelerated with assembly on any platform.

Technique used was minimax polynomial approximation using tables of
polynomial coefficients, with argument range reduction.

Benchmark         New     Old     Speedup
BenchmarkAcos     12.2    47.5    3.89
BenchmarkAcosh    18.5    56.2    3.04
BenchmarkAsin     13.1    40.6    3.10
BenchmarkAsinh    19.4    62.8    3.24
BenchmarkAtan     10.1    23      2.28
BenchmarkAtanh    19.1    53.2    2.79
BenchmarkAtan2    16.5    33.9    2.05
BenchmarkCbrt     14.8    58      3.92
BenchmarkErf      10.8    20.1    1.86
BenchmarkErfc     11.2    23.5    2.10
BenchmarkExp      8.77    53.8    6.13
BenchmarkExpm1    10.1    38.3    3.79
BenchmarkLog      13.1    40.1    3.06
BenchmarkLog1p    12.7    38.3    3.02
BenchmarkPowInt   31.7    40.5    1.28
BenchmarkPowFrac  33.1    141     4.26
BenchmarkTan      11.5    30      2.61

Accuracy was tested against a high precision
reference function to determine maximum error.
Note: ulperr is error in "units in the last place"

       max
      ulperr
Acos  1.15
Acosh 1.07
Asin  2.22
Asinh 1.72
Atan  1.41
Atanh 3.00
Atan2 1.45
Cbrt  1.18
Erf   1.29
Erfc  4.82
Exp   1.00
Expm1 2.26
Log   0.94
Log1p 2.39
Tan   3.14

Pow will have 99.99% correctly rounded results with reasonable inputs
producing numeric (non Inf or NaN) results

Change-Id: I850e8cf7b70426e8b54ec49d74acd4cddc8c6cb2
Reviewed-on: https://go-review.googlesource.com/38585
Reviewed-by: Michael Munday <munday@ca.ibm.com>
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-08 19:52:30 +00:00
Marvin Stenger
8c49c06b48 bytes: skip inline test by default
The test "TestTryGrowByResliceInlined" introduced in c08ac36 broke the
noopt builder as it fails when inlining is disabled.
Since there are currently no other options at hand for checking
inlined-ness other than looking at emited symbols of the compilation,
we for now skip the problem causing test by default and only run
it on one specific builder ("linux-amd64").
Also see CL 42813, which introduced the test and contains comments
suggesting this temporary solution.

Change-Id: I3978ab0831da04876cf873d78959f821c459282b
Reviewed-on: https://go-review.googlesource.com/42820
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2017-05-08 15:16:21 +00:00