Passes toolstash -cmp

Update #14473.

Change-Id: I15b35d40a5ec1f4355ee38bc6d131920933ac95c
Reviewed-on: https://go-review.googlesource.com/20237
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I01ec7d08884a1e0fbce94ea77281c1ee4a2cfd56
Reviewed-on: https://go-review.googlesource.com/20238Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Also fix some uses of nodeSeqIterator.Len, and fix the implementation in
nodesIterator.

Passes toolstash -cmp.

Update #14473.

Change-Id: I228871470234b7f1314ffd2aae8a4c0624c35f98
Reviewed-on: https://go-review.googlesource.com/20231
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

When the linker was written in C, command line arguments were passed
around as null-terminated byte arrays which encouraged checking
characters one at a time. In Go, that can easily lead to
out-of-bounds panics.

Use the more idiomatic strings.HasPrefix when checking cmd/link's -B
argument to avoid the panic, and replace the manual hex decode with
use of the encoding/hex package.

Fixes #14636

Change-Id: I45f765bbd8cf796fee1a9a3496178bf76b117827
Reviewed-on: https://go-review.googlesource.com/20211
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

gcMarkRootCheck takes ~10ns per goroutine. This is just a debugging
check, so disable it (plus, if something is going to go wrong, it's
more likely to go wrong during concurrent mark).

We may be able to re-enable this later, or move it to after we've
started the world again. (But not for 1.6.x.)

For 1.6.x.

Fixes #14419.

name / 95%ile-time/markTerm          old          new  delta
500kIdleGs-12                24.0ms ± 0%  18.9ms ± 6%  -21.46%  (p=0.000 n=15+20)

Change-Id: Idb2a2b1771449de772c159ef95920d6df1090666
Reviewed-on: https://go-review.googlesource.com/20148Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Currently we reset the mark state during STW sweep termination. This
involves looping over all of the goroutines. Each iteration of this
loop takes ~25ns, so at around 400k goroutines, we'll exceed our 10ms
pause goal.

However, it's safe to do this before we stop the world for sweep
termination because nothing is consuming this state yet. Hence, move
the reset to just before STW.

This isn't perfect: a long reset can still delay allocating goroutines
that block on GC starting. But it's certainly better to block some
things eventually than to block everything immediately.

For 1.6.x.

Fixes #14420.

name \ 95%ile-time/sweepTerm           old          new  delta
500kIdleGs-12                 11312µs ± 6%  18.9µs ± 6%  -99.83%  (p=0.000 n=16+20)

Change-Id: I9815c4d8d9b0d3c3e94dfdab78049cefe0dcc93c
Reviewed-on: https://go-review.googlesource.com/20147Reviewed-by: Rick Hudson <rlh@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Also fix compiler-invoked panics to avoid a confusing "malloc deadlock"
crash if they are invoked while executing the runtime.

Fixes #14599.

Change-Id: I89436abcbf3587901909abbdca1973301654a76e
Reviewed-on: https://go-review.googlesource.com/20219
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Many read-only strings in Go binaries are substrings of other read-only
strings. A common source is the text form of type information, which
will include both "struct { X int }" and "*struct { X int }" or
"*bytes.Reader" and "func(*bytes.Reader)" in the same binary.

Because this character data is referred to by separate string headers,
we can skip writing the smaller string and modify the pointer
relocation to point to the larger string. This CL does this
deduplication in the linker after the reachable set of strings has
been determined.

This removes 765KB from juju (1.4% without DWARF).

Link time goes at tip goes form 4.6s to 6.3s, but note that this CL
is part of a series that recently reduced link time from 9.6s.

For #6853.

Change-Id: Ib2087cf627c9f1e9a1181f9b4c8f81d1a3f42191
Reviewed-on: https://go-review.googlesource.com/19987Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

go test github.com/onsi/gomega/gbytes now passes at tip, and tests
added to the reflect package.

Fixes #14645

Change-Id: I16216c1a86211a1103d913237fe6bca5000cf885
Reviewed-on: https://go-review.googlesource.com/20221
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Minalign > 1 implies that relocations inserted by the linker cannot
target arbitrary bytes.

Related to #14604

Change-Id: Ie68d14887bc4047d9b29b0cb1149a8d14b6c62e2
Reviewed-on: https://go-review.googlesource.com/20214Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Passes toolstash -cmp.

Update #14473.

Change-Id: I60ef7cac553b346ca6b8cc7152cd184e59994b66
Reviewed-on: https://go-review.googlesource.com/20216
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

To turn ssa compilation on or off altogether, use
-ssa=1 or -ssa=0.  Default is on.

To turn on or off consistency checks, do
-d=ssa/check/on or -d=ssa/check/off.  Default is on for now.

Change-Id: I277e0311f538981c8b9c62e7b7382a0c8755ce4c
Reviewed-on: https://go-review.googlesource.com/20217Reviewed-by: David Chase <drchase@google.com>

Passing copy==1 to syslook is only necessary to support subsequent
calls to substArgTypes.  typ2Itab and concatstring* don't have "any"
parameters, so no point in deep copying their function signatures at
every call site.

For a couple other syslook calls (makemap and conv[IET]2[IET]), move
them closer to their corresponding substArgTypes calls so it's easier
to see that all syslook(fn, 1) calls are necessary.

Change-Id: I4a0588ab2b8b5b8ce7a0a44b24c8cf8fda489af6
Reviewed-on: https://go-review.googlesource.com/20215
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The changes to internal/big are completely automatic
by running vendor.bash in that directory.

Also added respective test case.

For #14553.

Change-Id: I98b124bcc9ad9e9bd987943719be27864423cb5d
Reviewed-on: https://go-review.googlesource.com/20199Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

When a big.Float is converted to a denormal float32/64, the rounding
precision depends on the size of the denormal. Rounding may round up
and thus change the size (exponent) of the denormal. Recompute the
correct precision again for correct placement of the mantissa.

Fixes #14553.

Change-Id: Iedab5810a2d2a405cc5da28c6de7be34cb035b86
Reviewed-on: https://go-review.googlesource.com/20198Reviewed-by: Alan Donovan <adonovan@google.com>

Makes godoc 37KB smaller.
For #6853.

Change-Id: I0bd6e40f2b4da193768a9fc2ce494cacf7e83c32
Reviewed-on: https://go-review.googlesource.com/19697
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I443f997ed53f965ef5b33734351ab8a07a09746b
Reviewed-on: https://go-review.googlesource.com/20213
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Pases toolstash -cmp.

Update #14473.

Change-Id: I450d9f51fd280da91952008cd917b749d88960a3
Reviewed-on: https://go-review.googlesource.com/20210
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Good riddance to another one-off linked list type.

Change-Id: Idf9926a701ab4da8a022be1d61f1257020d58fc5
Reviewed-on: https://go-review.googlesource.com/20212
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

This is mostly changing the opXXX helpers to take an int16 (matching Prog.As)
argument and return a uint32. The only bit that's not completely trivial is
passing -p.As to opirr to signal operating on a shifted constant, because AADD
+ ALAST overflows int16.

Change-Id: I69133800bbe41c38fa4a89bbbf49823043b3419c
Reviewed-on: https://go-review.googlesource.com/20182Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This CL addresses some issues noted during CL 20089.

Change-Id: I4e91a8077c07a571ccc9c004278672eb951c5104
Reviewed-on: https://go-review.googlesource.com/20181Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The existing implementation returns nil, ErrBufferFull when n > len(b.buf),
now it will return any data in the buffer and ErrBufferFull.

Fixes #14121

Change-Id: Ie52d32ccd80e4078ebfae6e75393c89675959ead
Reviewed-on: https://go-review.googlesource.com/19091
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Move a few local fields all the way to []*Node while I'm at it.

Update #14473.

Change-Id: Ib18360879839ac592f778cf1042f111bdf14add3
Reviewed-on: https://go-review.googlesource.com/20197
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Automated CL prepared by github.com/mdempsky/unconvert, except for
reverting changes to ssa/rewritegeneric.go (generated file) and
package big (vendored copy of math/big).

Change-Id: I64dc4199f14077c7b6a2f334b12249d4a785eadd
Reviewed-on: https://go-review.googlesource.com/20089
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Dave Cheney <dave@cheney.net>

Add new functions setNodeSeqNode, appendNodeSeq, appendNodeSeqNode.

Passes toolstash -cmp.

Change-Id: I6c1745b1108dea45a2c0d029b9de1917ae17a962
Reviewed-on: https://go-review.googlesource.com/20196
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

cmd/vet's printf checker currently uses a hardcoded map of function
names to expected positions of format strings. We can be a bit more
precise than this by looking up the signature of the function, which
helps when libraries implement functions like Errorf or Logf with
extra arguments like log levels or error codes.

Specifically, the format string param is assumed to be the last string
parameter of the called function.

Fixes #12294.

Change-Id: Icf10ebb819bba91fa1c4109301417042901e34c7
Reviewed-on: https://go-review.googlesource.com/20163
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

Added Seq method to nodeListIterator. Added new functions nodeSeqLen,
nodeSeqFirst, nodeSeqSecond. Allow nil as source argument to setNodeSeq.

Change-Id: Ifc1cd4d7207b7a125b3830c92c4d6d6f00eedd54
Reviewed-on: https://go-review.googlesource.com/20195Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Also rewrite bexport.go to use nodeSeqIterate.

The new setNodeSeq is a transitional generic function to set either a
NodeList or a slice to either a NodeList or a slice.  This should permit
us to flip fields from *NodeList to []*Node, or Nodes, without changing
other code.

Passes toolstash -cmp.

Change-Id: I872cbfe45bc5f432595737c1f6da641c502b1ab6
Reviewed-on: https://go-review.googlesource.com/20194Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The ssa compiler uses the duffcopy and duffzero functions,
which rely on the MOVUPS instructions.

However, this doesn't work on Plan 9, since floating point
operations are not allowed in the note handler.

This change disables the use of duffcopy and duffzero
on Plan 9 in the ssa compiler.

Updates #14605.

Change-Id: I017f8ff83de00eabaf7e146b4344a863db1dfddc
Reviewed-on: https://go-review.googlesource.com/20171Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

I tried to write a program to convert *NodeList to Node, but ran into
too many problem cases.  I'm backing off and trying a more iterative
approach using interfaces.

This CL adds an interface for iteration over either a *NodeList or a
Nodes.  I changed typechecklist to use it, to show how it works.  After
NodeList is eliminated, we can change the typechecklist parameter type
to Nodes.

Passes toolstash -cmp.

Change-Id: I5c7593714b020d20868b99151b1e7cadbbdbc397
Reviewed-on: https://go-review.googlesource.com/20190
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This CL introduces a mergestrings pass after the reachability
analysis to combine all reachable go.string."..." character data
symbols into a single symbol.

Shrinks juju by 1.2mb (1.5%).
Shrinks cmd/go by 0.5% when building without DWARF.
No noticable effect on linker speed.

Change-Id: I2ba3e60bf418f65766bda257f6ca9eea26d895b6
Reviewed-on: https://go-review.googlesource.com/20165
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The listsort function is no longer used, except in a test.  Change the
test to use sort.Sort instead.

Change-Id: Ib634705cc1bc3b1d8fc3795bd4ed2894e6abc284
Reviewed-on: https://go-review.googlesource.com/19964Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Make sure we don't depend on map iterator order.

Fixes #14600

Change-Id: Iac0e0c8689f3ace7a4dc8e2127e2fd3c8545bd29
Reviewed-on: https://go-review.googlesource.com/20158
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

If we're about to enter a loop, load values which are live
and will soon be used in the loop into registers.

name                     old time/op    new time/op    delta
BinaryTree17-8              2.80s ± 4%     2.62s ± 2%   -6.43%          (p=0.008 n=5+5)
Fannkuch11-8                2.45s ± 2%     2.14s ± 1%  -12.43%          (p=0.008 n=5+5)
FmtFprintfEmpty-8          49.0ns ± 1%    48.4ns ± 1%   -1.35%          (p=0.032 n=5+5)
FmtFprintfString-8          160ns ± 1%     153ns ± 0%   -4.63%          (p=0.008 n=5+5)
FmtFprintfInt-8             152ns ± 0%     150ns ± 0%   -1.57%          (p=0.000 n=5+4)
FmtFprintfIntInt-8          252ns ± 2%     244ns ± 1%   -3.02%          (p=0.008 n=5+5)
FmtFprintfPrefixedInt-8     223ns ± 0%     223ns ± 0%     ~     (all samples are equal)
FmtFprintfFloat-8           293ns ± 2%     291ns ± 2%     ~             (p=0.389 n=5+5)
FmtManyArgs-8               956ns ± 0%     936ns ± 0%   -2.05%          (p=0.008 n=5+5)
GobDecode-8                7.18ms ± 0%    7.11ms ± 0%   -1.02%          (p=0.008 n=5+5)
GobEncode-8                6.12ms ± 3%    6.07ms ± 1%     ~             (p=0.690 n=5+5)
Gzip-8                      284ms ± 1%     284ms ± 0%     ~             (p=1.000 n=5+5)
Gunzip-8                   40.8ms ± 1%    40.6ms ± 1%     ~             (p=0.310 n=5+5)
HTTPClientServer-8         69.8µs ± 1%    72.2µs ± 4%     ~             (p=0.056 n=5+5)
JSONEncode-8               16.1ms ± 2%    16.2ms ± 1%     ~             (p=0.151 n=5+5)
JSONDecode-8               54.9ms ± 0%    57.0ms ± 1%   +3.79%          (p=0.008 n=5+5)
Mandelbrot200-8            4.35ms ± 0%    4.39ms ± 0%   +0.85%          (p=0.008 n=5+5)
GoParse-8                  3.56ms ± 1%    3.42ms ± 1%   -4.03%          (p=0.008 n=5+5)
RegexpMatchEasy0_32-8      75.6ns ± 1%    75.0ns ± 0%   -0.83%          (p=0.016 n=5+4)
RegexpMatchEasy0_1K-8       250ns ± 0%     252ns ± 1%   +0.80%          (p=0.016 n=4+5)
RegexpMatchEasy1_32-8      75.0ns ± 0%    75.4ns ± 2%     ~             (p=0.206 n=5+5)
RegexpMatchEasy1_1K-8       401ns ± 0%     398ns ± 1%     ~             (p=0.056 n=5+5)
RegexpMatchMedium_32-8      119ns ± 0%     118ns ± 0%   -0.84%          (p=0.008 n=5+5)
RegexpMatchMedium_1K-8     36.6µs ± 0%    36.9µs ± 0%   +0.91%          (p=0.008 n=5+5)
RegexpMatchHard_32-8       1.95µs ± 1%    1.92µs ± 0%   -1.23%          (p=0.032 n=5+5)
RegexpMatchHard_1K-8       58.3µs ± 1%    58.1µs ± 1%     ~             (p=0.548 n=5+5)
Revcomp-8                   425ms ± 1%     389ms ± 1%   -8.39%          (p=0.008 n=5+5)
Template-8                 65.5ms ± 1%    63.6ms ± 1%   -2.86%          (p=0.008 n=5+5)
TimeParse-8                 363ns ± 0%     354ns ± 1%   -2.59%          (p=0.008 n=5+5)
TimeFormat-8                363ns ± 0%     364ns ± 1%     ~             (p=0.159 n=5+5)

Fixes #14511

Change-Id: I1b79d2545271fa90d5b04712cc25573bdc94f2ce
Reviewed-on: https://go-review.googlesource.com/20151
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

Change-Id: I939129da0e71a7ccc61bec79515a34f0b1e59502
Reviewed-on: https://go-review.googlesource.com/20162Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Idc95452088d23be8e18522209d98f789dfca070b
Reviewed-on: https://go-review.googlesource.com/20161Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #14547.

Change-Id: Ic175ee8f7e65b9b99f1f47fbf267a2aba7c8fec7
Reviewed-on: https://go-review.googlesource.com/20010
Run-TryBot: Caleb Spare <cespare@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

No extra buffering is needed to save the encoding
since the left padding can be computed and written out
before the encoding is generated.

Add extra tests to both string and byte slice formatting.

name                old time/op  new time/op  delta
SprintfHexString-2   410ns ± 3%   194ns ± 3%  -52.60%  (p=0.000 n=20+19)
SprintfHexBytes-2    431ns ± 3%   202ns ± 2%  -53.13%  (p=0.000 n=18+20)

Change-Id: Ibca4316427c89f834e4faee61614493c7eedb42b
Reviewed-on: https://go-review.googlesource.com/20097
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

The ODOTPTRs introduced in CL #19814 don't have field names,
just offsets.  The fieldtrack experiment crashes when
examining them.  Instead, just ignore them.  We'll never track
these fields anyway.

It would be nice to have the runtime type struct build in the
compiler (like we do sudog, for example) so we could use its
fieldnames.  Doesn't seem worth it just for this CL.

Change-Id: I5e75024f5a8333eb7439543b3f466ea40213a1b9
Reviewed-on: https://go-review.googlesource.com/20157Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ib0a116a78f61eafe88a0ea5dc6733750ae755fdf
Reviewed-on: https://go-review.googlesource.com/20156
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>