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Update #17410
Update #19142
Fixes #19986

Change-Id: I21d16d254161c75466b31c670f3b2c8c463abd66
Reviewed-on: https://go-review.googlesource.com/41205
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Make poolLocal size multiple of 128, so it aligns to CPU cache line
on the most common architectures.

This also has the following benefits:

- It may help compiler substituting integer multiplication
  by bit shift inside indexLocal.
- It shrinks poolLocal size from 176 bytes to 128 bytes on amd64,
  so now it fits two cache lines (or a single cache line on certain
  Intel CPUs - see https://software.intel.com/en-us/articles/optimizing-application-performance-on-intel-coret-microarchitecture-using-hardware-implemented-prefetchers).

No measurable performance changes on linux/amd64 and linux/386.

Change-Id: I11df0f064718a662e77a85d88b8a15a8919f25e9
Reviewed-on: https://go-review.googlesource.com/40918Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #8438

Change-Id: Ib43cdcdc962a8d9e14faf984bc859a92ba1eb517
Reviewed-on: https://go-review.googlesource.com/40531Reviewed-by: Robert Griesemer <gri@golang.org>

There were only two versions, 0 and 1,
and the only user of version 1 was the assembler,
to indicate that a symbol was static.

Rename LSym.Version to Static,
and add it to LSym.Attributes.
Simplify call-sites.

Passes toolstash-check.

Change-Id: Iabd39918f5019cce78f381d13f0481ae09f3871f
Reviewed-on: https://go-review.googlesource.com/41201
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Imported interfaces must be completed, whether they are named or not.
The original code was collecting all types (including anonymous ones)
in the importer's typList. That list was used in the end to complete
interface types. When we introduced tracking of named types only, we
lost anonymous interfaces. Use an independent list of interface types
so the completion code is independent of which types are tracked.

Added test and factored some of the existing tests.

Fixes #20046.

Change-Id: Icd1329032aec33f96890380dd5042de3bef8cdc7
Reviewed-on: https://go-review.googlesource.com/41198Reviewed-by: Matthew Dempsky <mdempsky@google.com>

TestBreakpoint expects to see "runtime.Breakpoint()" in the stack trace.
If runtime.Breakpoint() is inlined, then the stack trace prints
"runtime.Breakpoint(...)" since the runtime does not have information
about arguments (or lack thereof) to inlined functions. This change
makes the test independent of inlining by looking for the string
"runtime.Breakpoint(". Now TestBreakpoint passes with -l=4.

Change-Id: Ia044a8e8a4de2337cb2b393d6fa78c73a2f25926
Reviewed-on: https://go-review.googlesource.com/40997
Run-TryBot: David Lazar <lazard@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

TestBlockProfile matches samples against a regexp that accepts "," in
profile PCs. I suspect this was just a syntax mistake. Remove "," from
the character class.

Change-Id: Idcfc20ed6900075abae08597ba71db559e89b37b
Reviewed-on: https://go-review.googlesource.com/41111
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Peter Weinberger <pjw@google.com>

TestBlockProfile currently requires exactly five PCs in each sample.
With more aggressive inlining there may be fewer, so change this test
to use the same pattern as TestMutexProfile, which accepts one or more
PCs. With this change, this test passes when compiled with -l=4.

Change-Id: I1421a6d56c96b77111bdc671d88723a222672fd6
Reviewed-on: https://go-review.googlesource.com/41110
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Lazar <lazard@golang.org>

CL 40876 changed ExampleFrames so that the output
was stable with and without mid-stack inlining.

However, that change lost some of the
pedagogical and copy/paste value of the example.
It was unclear why both more and i were being tracked,
and whether the 5 in i < 5 is related to len(pc),
and if so, why and how.

This CL rewrites the example with lots more comments,
and such that the core structure more closely matches
normal usage, and such that it is obvious
which lines of code should be deleted when copying.
As a bonus, it also now illustrates Frame.File.

Change-Id: Iab73541dd096657ddf79c5795337e8b596d89740
Reviewed-on: https://go-review.googlesource.com/41136
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

The period recorded in CPU profiles is in nanoseconds, but was being
computed incorrectly as hz * 1000. As a result, many absolute times
displayed by pprof were incorrect.

Fix this by computing the period correctly.

Change-Id: I6fadd6d8ad3e57f31e8cc7a25a24fcaec510d8d4
Reviewed-on: https://go-review.googlesource.com/40995
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Russ Cox <rsc@golang.org>

Convert the parsed attribute name to lowercase before checking its value in
the HTML parser state machine. This ensures that the type attribute in
the script element is handled in a case-sensitive manner, just like all
other attribute names.

Fixes #19965

Change-Id: I806d8c62aada2c3b5b4328aff75f217ea60cb339
Reviewed-on: https://go-review.googlesource.com/40650
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

The arch backends no longer depend on gc.Node.

Passes toolstash-check -all.

Change-Id: Ic7e49ae0a3ed155a2761c25e17cc341b46333fb4
Reviewed-on: https://go-review.googlesource.com/41196
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

VEX encoded instructions don't have a REX byte, so for PC relative
addressing we don't need to recalculate relocation offset.

Fixes #19518

Change-Id: Icf5414962de4350d76fd220817498337f90614fc
Reviewed-on: https://go-review.googlesource.com/38138
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Handle MIME types found in the type attribute of the script element
in a case insensitive way, as per Section 5.1 of RFC 2045.

Fixes #19968

Change-Id: Ie1416178c937dcf2c96bcec4191cebe7c3477af8
Reviewed-on: https://go-review.googlesource.com/40702Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This updates PPC64.rules to include rules to generate rotates
for ADD, OR, XOR operators that combine two opposite shifts
that sum to 32 or 64.

To support this change opcodes for ROTL and ROTLW were added to
be used like the rotldi and rotlwi extended mnemonics.

This provides the following improvement in sha3:

BenchmarkPermutationFunction-8     302.83       376.40       1.24x
BenchmarkSha3_512_MTU-8            98.64        121.92       1.24x
BenchmarkSha3_384_MTU-8            136.80       168.30       1.23x
BenchmarkSha3_256_MTU-8            169.21       211.29       1.25x
BenchmarkSha3_224_MTU-8            179.76       221.19       1.23x
BenchmarkShake128_MTU-8            212.87       263.23       1.24x
BenchmarkShake256_MTU-8            196.62       245.60       1.25x
BenchmarkShake256_16x-8            163.57       194.37       1.19x
BenchmarkShake256_1MiB-8           199.02       248.74       1.25x
BenchmarkSha3_512_1MiB-8           106.55       133.13       1.25x

Fixes #20030

Change-Id: I484c56f48395d32f53ff3ecb3ac6cb8191cfee44
Reviewed-on: https://go-review.googlesource.com/40992
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
Reviewed-by: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #19207

Change-Id: I69b70492fd01599a13c1a3beb87f492de40a18b0
Reviewed-on: https://go-review.googlesource.com/37312Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I4204e268c7220a50ceb270432067850ec2b5af80
Reviewed-on: https://go-review.googlesource.com/41230Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Instead of populating the aux symbol
of CALLudiv during rewrite rules,
populate it during genssa.

This simplifies the rewrite rules.
It also removes all remaining calls
to ctxt.Lookup from any rewrite rules.
This is a first step towards removing
ctxt from ssa.Cache entirely,
and also a first step towards converting
the obj.LSym.Version field into a boolean.
It should also speed up compilation.

Also, move func udiv into package runtime.
That's where it is anyway,
and it lets udiv look and act like the rest of
the runtime support functions.

Change-Id: I41462a632c14fdc41f61b08049ec13cd80a87bfe
Reviewed-on: https://go-review.googlesource.com/41191
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Though LSym.Version is an int, it can only have the value 0 or 1.
Using that, split Link.hash into two maps, one for version 0
(which is far more common) and one for version 1.
This lets use just the name for lookups,
which is both faster and more compact.
This matters because Link.hash map lookups are frequent,
and will be contended once the backend is concurrent.

name        old time/op       new time/op       delta
Template          194ms ± 3%        192ms ± 5%  -1.46%  (p=0.000 n=47+49)
Unicode          84.5ms ± 3%       83.8ms ± 3%  -0.81%  (p=0.011 n=50+49)
GoTypes           543ms ± 2%        545ms ± 4%    ~     (p=0.566 n=46+49)
Compiler          2.48s ± 2%        2.48s ± 3%    ~     (p=0.706 n=47+50)
SSA               5.94s ± 3%        5.98s ± 2%  +0.55%  (p=0.040 n=49+50)
Flate             119ms ± 6%        119ms ± 4%    ~     (p=0.681 n=48+47)
GoParser          145ms ± 4%        145ms ± 3%    ~     (p=0.662 n=47+49)
Reflect           348ms ± 3%        344ms ± 3%  -1.17%  (p=0.000 n=47+47)
Tar               105ms ± 4%        104ms ± 3%    ~     (p=0.155 n=50+47)
XML               197ms ± 2%        197ms ± 3%    ~     (p=0.666 n=49+49)
[Geo mean]        332ms             331ms       -0.37%

name        old user-time/op  new user-time/op  delta
Template          230ms ±10%        226ms ±10%  -1.85%  (p=0.041 n=50+50)
Unicode           104ms ± 6%        103ms ± 5%    ~     (p=0.076 n=49+49)
GoTypes           707ms ± 4%        705ms ± 5%    ~     (p=0.521 n=50+50)
Compiler          3.30s ± 3%        3.33s ± 4%  +0.76%  (p=0.003 n=50+49)
SSA               8.17s ± 4%        8.23s ± 3%  +0.66%  (p=0.030 n=50+49)
Flate             139ms ± 6%        138ms ± 8%    ~     (p=0.184 n=49+48)
GoParser          174ms ± 5%        172ms ± 6%    ~     (p=0.107 n=48+49)
Reflect           431ms ± 8%        420ms ± 5%  -2.57%  (p=0.000 n=50+46)
Tar               119ms ± 6%        118ms ± 7%  -0.95%  (p=0.033 n=50+49)
XML               236ms ± 4%        236ms ± 4%    ~     (p=0.935 n=50+48)
[Geo mean]        410ms             407ms       -0.67%

name        old alloc/op      new alloc/op      delta
Template         38.7MB ± 0%       38.6MB ± 0%  -0.29%  (p=0.008 n=5+5)
Unicode          29.8MB ± 0%       29.7MB ± 0%  -0.24%  (p=0.008 n=5+5)
GoTypes           113MB ± 0%        113MB ± 0%  -0.29%  (p=0.008 n=5+5)
Compiler          462MB ± 0%        462MB ± 0%  -0.12%  (p=0.008 n=5+5)
SSA              1.27GB ± 0%       1.27GB ± 0%  -0.05%  (p=0.008 n=5+5)
Flate            25.2MB ± 0%       25.1MB ± 0%  -0.37%  (p=0.008 n=5+5)
GoParser         31.7MB ± 0%       31.6MB ± 0%    ~     (p=0.056 n=5+5)
Reflect          77.5MB ± 0%       77.2MB ± 0%  -0.38%  (p=0.008 n=5+5)
Tar              26.4MB ± 0%       26.3MB ± 0%    ~     (p=0.151 n=5+5)
XML              41.9MB ± 0%       41.9MB ± 0%  -0.20%  (p=0.032 n=5+5)
[Geo mean]       74.5MB            74.3MB       -0.23%

name        old allocs/op     new allocs/op     delta
Template           378k ± 1%         377k ± 1%    ~     (p=0.690 n=5+5)
Unicode            321k ± 0%         322k ± 0%    ~     (p=0.595 n=5+5)
GoTypes           1.14M ± 0%        1.14M ± 0%    ~     (p=0.310 n=5+5)
Compiler          4.25M ± 0%        4.25M ± 0%    ~     (p=0.151 n=5+5)
SSA               9.84M ± 0%        9.84M ± 0%    ~     (p=0.841 n=5+5)
Flate              232k ± 1%         232k ± 0%    ~     (p=0.690 n=5+5)
GoParser           315k ± 1%         315k ± 1%    ~     (p=0.841 n=5+5)
Reflect            970k ± 0%         970k ± 0%    ~     (p=0.841 n=5+5)
Tar                248k ± 0%         248k ± 1%    ~     (p=0.841 n=5+5)
XML                389k ± 0%         389k ± 0%    ~     (p=1.000 n=5+5)
[Geo mean]         724k              724k       +0.01%

Updates #15756

Change-Id: I2646332e89f0444ca9d5a41d7172537d904ed636
Reviewed-on: https://go-review.googlesource.com/41050
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

As of CL 39998, it is no longer necessary.

Fixes #19699

Change-Id: Ie1c49c8468073c6ddeb96c03668705cf81d40c98
Reviewed-on: https://go-review.googlesource.com/41051
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

ld.ldelf contained a mixture of normal and C style, goto bad, error
handling. The use of goto requires many variables to be declared well
before their use which inhibited further refactoring to this method.

This CL removes the gotos in this function. Future CLs will address
remainder of the C style function scoped declarations in this function.

Change-Id: Ib9def495209a2f8deb11dcf30ee954bca95390c6
Reviewed-on: https://go-review.googlesource.com/41172
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

obj.Linksymfmt is no longer referenced by any packages in cmd/...

Change-Id: Id4d9213d1577e13580b60755dbf7da313b17cb0e
Reviewed-on: https://go-review.googlesource.com/41171
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The dclstack is now a proper stack and thus we can implement it
using a slice rather than a linked list.

Change-Id: I200e85621ff76c111bdeb7eb382fd82da438f3ba
Reviewed-on: https://go-review.googlesource.com/41135Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #20014

Change-Id: Ie58d3e989f2d7388b3d8849fbcfbceed3c6aa084
Reviewed-on: https://go-review.googlesource.com/41132
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ie8fd7839806b4a6bcfac5ac1f984db7ab282c3b5
Reviewed-on: https://go-review.googlesource.com/41150
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: David Lazar <lazard@golang.org>

- PkgMap was only needed to test import/export in a "cleanroom"
  environment, with debugFormat set. Provided helper function
  instead.

- PkgList was only used to identify directly imported packages.
  Instead, compute that list explicitly from the package map.
  It happens only once, the list is small, and it's more robust
  than keeping two data structures in sync.

Change-Id: I82dce3c0b5cb816faae58708e877799359c20fcb
Reviewed-on: https://go-review.googlesource.com/41078Reviewed-by: Matthew Dempsky <mdempsky@google.com>

There's already special code to access it.

Change-Id: I28ca4f44a04262407ee9f1c826ada4e7eba44775
Reviewed-on: https://go-review.googlesource.com/41073Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Change-Id: I08b43b08a8d2e9851f41401feee4b72287ced774
Reviewed-on: https://go-review.googlesource.com/41072Reviewed-by: Matthew Dempsky <mdempsky@google.com>

That's where it belongs. Also, moved pkgMap and pkgs globals.

Change-Id: I531727fe5ce162c403efefec82f4cc90afa326d7
Reviewed-on: https://go-review.googlesource.com/41071Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Returns at the end of func bodies where the funcs have no return values
are pointless.

Change-Id: I0da5ea78671503e41a9f56dd770df8c919310ce5
Reviewed-on: https://go-review.googlesource.com/41093
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Such dead code is legitimate when dealing with arch-specific
types (int, uint, uintptr).

The CL removes the majority of 'too small for shift' false positives
from such a code.

Change-Id: I62c5635a1d3774ab2d71d3d7056f0589f214cbe5
Reviewed-on: https://go-review.googlesource.com/38065
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

When we switched to SSA R0 was made allocatable and no longer holds
zero on s390x.

Change-Id: I1c752bb02da35462a535492379345fa9f4e12cb0
Reviewed-on: https://go-review.googlesource.com/41079Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This displays the swept and reclaimed bytes for sweep events in the
lower panel of the trace viewer.

Change-Id: If1665a1c02bbc47700e0d9f515e574f013f3f285
Reviewed-on: https://go-review.googlesource.com/40812
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

This extends the GCSweepDone event with counts of swept and reclaimed
bytes. These are useful for understanding the duration and
effectiveness of sweep events.

Change-Id: I3c97a4f0f3aad3adbd188adb264859775f54e2df
Reviewed-on: https://go-review.googlesource.com/40811
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Currently, each individual span sweep emits a span to the trace. But
sweeps are generally done in loops until some condition is satisfied,
so this tracing is lower-level than anyone really wants any hides the
fact that no other work is being accomplished between adjacent sweep
events. This is also high overhead: enabling tracing significantly
impacts sweep latency.

Replace this with instead tracing around the sweep loops used for
allocation. This is slightly tricky because sweep loops don't
generally know if any sweeping will happen in them. Hence, we make the
tracing lazy by recording in the P that we would like to start tracing
the sweep *if* one happens, and then only closing the sweep event if
we started it.

This does mean we don't get tracing on every sweep path, which are
legion. However, we get much more informative tracing on the paths
that block allocation, which are the paths that matter.

Change-Id: I73e14fbb250acb0c9d92e3648bddaa5e7d7e271c
Reviewed-on: https://go-review.googlesource.com/40810
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Changes the text to match GOOS which appends 'and so on' at the
end to avoid restricting the set of possible values.

Change-Id: I54bcde71334202cf701662cdc2582c974ba8bf53
Reviewed-on: https://go-review.googlesource.com/41074Reviewed-by: Ian Lance Taylor <iant@golang.org>

Patch from Vlad Krasnov and confirmed to be under CLA.

Fixes #20040.

Change-Id: Ieb8436c4dcb6669a1620f1e0d257efd047b1b87c
Reviewed-on: https://go-review.googlesource.com/41070
Run-TryBot: Adam Langley <agl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

When allocating a non-small array of buckets for a map,
also preallocate some overflow buckets.

The estimate of the number of overflow buckets
is based on a simulation of putting mid=(low+high)/2 elements
into a map, where low is the minimum number of elements
needed to reach this value of b (according to overLoadFactor),
and high is the maximum number of elements possible
to put in this value of b (according to overLoadFactor).
This estimate is surprisingly reliable and accurate.

The number of overflow buckets needed is quadratic,
for a fixed value of b.
Using this mid estimate means that we will overallocate a few
too many overflow buckets when the actual number of elements is near low,
and underallocate significantly too few overflow buckets
when the actual number of elements is near high.

The mechanism introduced in this CL can be re-used for
other overflow bucket optimizations.

For example, given an initial size hint,
we could estimate quite precisely the number of overflow buckets.
This is #19931.

We could also change from "non-nil means end-of-list"
to "pointer-to-hmap.buckets means end-of-list",
and then create a linked list of reusable overflow buckets
when they are freed by map growth.
That is #19992.

We could also use a similar mechanism to do bulk allocation
of overflow buckets.
All these uses can co-exist with only the one additional pointer
in mapextra, given a little care.

name                  old time/op    new time/op    delta
MapPopulate/1-8         60.1ns ± 2%    60.3ns ± 2%     ~     (p=0.278 n=19+20)
MapPopulate/10-8         577ns ± 1%     578ns ± 1%     ~     (p=0.140 n=20+20)
MapPopulate/100-8       8.06µs ± 1%    8.19µs ± 1%   +1.67%  (p=0.000 n=20+20)
MapPopulate/1000-8       104µs ± 1%     104µs ± 1%     ~     (p=0.317 n=20+20)
MapPopulate/10000-8      891µs ± 1%     888µs ± 1%     ~     (p=0.101 n=19+20)
MapPopulate/100000-8    8.61ms ± 1%    8.58ms ± 0%   -0.34%  (p=0.009 n=20+17)

name                  old alloc/op   new alloc/op   delta
MapPopulate/1-8          0.00B          0.00B          ~     (all equal)
MapPopulate/10-8          179B ± 0%      179B ± 0%     ~     (all equal)
MapPopulate/100-8       3.33kB ± 0%    3.38kB ± 0%   +1.48%  (p=0.000 n=20+16)
MapPopulate/1000-8      55.5kB ± 0%    53.4kB ± 0%   -3.84%  (p=0.000 n=19+20)
MapPopulate/10000-8      432kB ± 0%     428kB ± 0%   -1.06%  (p=0.000 n=19+20)
MapPopulate/100000-8    3.65MB ± 0%    3.62MB ± 0%   -0.70%  (p=0.000 n=20+20)

name                  old allocs/op  new allocs/op  delta
MapPopulate/1-8           0.00           0.00          ~     (all equal)
MapPopulate/10-8          1.00 ± 0%      1.00 ± 0%     ~     (all equal)
MapPopulate/100-8         18.0 ± 0%      17.0 ± 0%   -5.56%  (p=0.000 n=20+20)
MapPopulate/1000-8        96.0 ± 0%      72.6 ± 1%  -24.38%  (p=0.000 n=20+20)
MapPopulate/10000-8        625 ± 0%       319 ± 0%  -48.86%  (p=0.000 n=20+20)
MapPopulate/100000-8     6.23k ± 0%     4.00k ± 0%  -35.79%  (p=0.000 n=20+20)

Change-Id: I01f41cb1374bdb99ccedbc00d04fb9ae43daa204
Reviewed-on: https://go-review.googlesource.com/40979
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Updates #19931
Updates #19992

Change-Id: Ib2d4e6b9b89a49caa443310d896dce8d6db06050
Reviewed-on: https://go-review.googlesource.com/40978
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

bmap already has a overflow (getter) method.
Add a setoverflow (setter) method, for readability.

Updates #19931
Updates #19992

Change-Id: I00b3d94037c0d75508a7ebd51085c5c3857fb764
Reviewed-on: https://go-review.googlesource.com/40977
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>