Current assembler encodes "ADD $0xaaaaaaaa, Rx" to "MOVD off(PC), Rtmp"
 + "ADD Rtmp, Rx", and a 64-bit item is stored in the constant pool.

This patch optimizes it to "MOVWU off(PC), Rtmp" + "ADD Rtmp, Rx",
and a 32-bit item is stored.

The total size of the executable binary go and the library files in
pkg/linux_arm64 decreased about 3KB by this patch.

Change-Id: Ieb1592f78ef9ed52f5d3ad232d6cdf87d0923de1
Reviewed-on: https://go-review.googlesource.com/107516Reviewed-by: Wei Xiao <Wei.Xiao@arm.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Update #18085
Fixes #24009

Change-Id: I655ad76284480002f8d49da269be92ded306128b
Reviewed-on: https://go-review.googlesource.com/107077Reviewed-by: Rob Pike <r@golang.org>

Vendor from golang.org/x/arch repo.  Pull in commits that update
arm64, arm, ppc64 and x86 directories (the latest commit 9111c30).

Change-Id: I2b4b3ea9662e69bcf0eeee9c6aba0118175524df
Reviewed-on: https://go-review.googlesource.com/107695
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes gosimple warning "if err != nil { return err };
return nil' can be simplified to 'return err"

Change-Id: Ife7f78a3a76ab7802b5561d1afec536e103b504a
Reviewed-on: https://go-review.googlesource.com/108275Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The patch rewrites the content of doc.go file. The file describes some
general rules of the mapping between Go assembly syntax and GNU syntax.
And it gives some Go assembly examples and corresponding GNU assembly
examples.

The patch changes the doc.go to use standard doc comment format so that
the link https://golang.org/cmd/internal/obj/arm64/ can display it.

Assembly document framework is mainly contributed by Eric Fang <Eric.Fang@arm.com>
Documentation work is contributed by Eric Fang and Fannie Zhang <Fannie.Zhang@arm.com>

Change-Id: I8b3f6d6c6b91afdc2c44602e8f796beea905085e
Reviewed-on: https://go-review.googlesource.com/102055Reviewed-by: Rob Pike <r@golang.org>

There are a bunch of places where we generate functions: equality and
hash functions; method expression and promoted method wrappers; and
print/delete wrappers for defer/go statements.

This CL brings them in sync by:

1) Always using dclfunc and funcbody. Most were already using this,
but makepartialcall needed some changes.

2) Removing duplicate types.Markdcl/types.Popdcl calls. These are
already handled by dclfunc and funcbody.

3) Using structargs (already used by genwrapper) to construct new
param/result lists from existing types.

4) Always accessing the parameter ONAME nodes through Field.Nname
instead of poking into the ODCLFIELD. Also, since creating a slice of
the entire parameter list is common, extract this out into a
paramNnames helper function.

5) Add a Type.IsVariadic method to simplify identifying variadic
function types.

Passes toolstash-check -gcflags=-dwarf=false. DWARF output changes
because using structargs in makepartialcall changes the generated
parameter names.

Change-Id: I6661d3699afdbe7852ad60db5a4ec6eeb2b696e4
Reviewed-on: https://go-review.googlesource.com/108216
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

On Unix systems, the underlying socket is no longer forced into blocking
mode.

Fixes #24942

Change-Id: I3e0c503c72df0844e30a63af298691dedacd1f46
Reviewed-on: https://go-review.googlesource.com/108297
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

By simply rearranging the logic, we avoid the overhead of a superfluous
call to getsockopt. For, if p is already non empty, there's no point
in having to check if we need to attach dummy payload. This has
performance benefits when using send/recvmsg for high speed
communications.

Change-Id: Id85cff17328ecbf6d09dd52fbeeaa691dbe69b75
Reviewed-on: https://go-review.googlesource.com/108338Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
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This is to allow followup refactorings that will replace
Field.Nname.Pos with Field.Pos.

Passes toolstash-check.

Change-Id: I1060b6a37c60273892f7af5369809057cff61881
Reviewed-on: https://go-review.googlesource.com/108215
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: Robert Griesemer <gri@golang.org>

Fixes golint warning about "if block ends with a return statement,
so drop this else and outdent its block".

Change-Id: Iac4fd324e04e3e3fe3e3933f5e59095041d292c5
Reviewed-on: https://go-review.googlesource.com/107115Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
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Fixes #23373

Fix interfacing with latest(1.4+) pkgconf versions, as they have change the
output format, by extending parsing function splitPkgConfigOutput to accommodate
more possible fragment escaping formats. Function is based on pkgconfigs own
implementation at
https://github.com/pkgconf/pkgconf/blob/master/libpkgconf/argvsplit.c. Along
with this change test case TestSplitPkgConfigOutput have been expanded. Thanks
to ignatenko for help on test cases and insights in to the pkgconfig.

Change-Id: I55301bb564b07128d5564ec1454dd247f84a95c3
Reviewed-on: https://go-review.googlesource.com/86541
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ie4da1a515d5405140d742bdcd55f54a73a7f71fe
Reviewed-on: https://go-review.googlesource.com/108175Reviewed-by: Ian Lance Taylor <iant@golang.org>

ARM64 supports load/store instructions with a memory operand that
the address is calculated by base register + index register.

In this CL,
1. Some rules are added to the compile's ARM64 backend to emit
such efficient instructions.
2. A wrong rule of load combination is fixed.

The go1 benchmark does show improvement.

name                     old time/op    new time/op    delta
BinaryTree17-4              44.5s ± 2%     44.1s ± 1%   -0.81%  (p=0.000 n=28+29)
Fannkuch11-4                32.7s ± 3%     30.5s ± 0%   -6.79%  (p=0.000 n=30+26)
FmtFprintfEmpty-4           499ns ± 0%     506ns ± 5%   +1.39%  (p=0.003 n=25+30)
FmtFprintfString-4         1.07µs ± 0%    1.04µs ± 4%   -3.17%  (p=0.000 n=23+30)
FmtFprintfInt-4            1.15µs ± 4%    1.13µs ± 0%   -1.55%  (p=0.000 n=30+23)
FmtFprintfIntInt-4         1.77µs ± 4%    1.74µs ± 0%   -1.71%  (p=0.000 n=30+24)
FmtFprintfPrefixedInt-4    2.37µs ± 5%    2.12µs ± 0%  -10.56%  (p=0.000 n=30+23)
FmtFprintfFloat-4          3.03µs ± 1%    3.03µs ± 4%   -0.13%  (p=0.003 n=25+30)
FmtManyArgs-4              7.38µs ± 1%    7.43µs ± 4%   +0.59%  (p=0.003 n=25+30)
GobDecode-4                 101ms ± 6%      95ms ± 5%   -5.55%  (p=0.000 n=30+30)
GobEncode-4                78.0ms ± 4%    78.8ms ± 6%   +1.05%  (p=0.000 n=30+30)
Gzip-4                      4.25s ± 0%     4.27s ± 4%   +0.45%  (p=0.003 n=24+30)
Gunzip-4                    428ms ± 1%     420ms ± 0%   -1.88%  (p=0.000 n=23+23)
HTTPClientServer-4          549µs ± 1%     541µs ± 1%   -1.56%  (p=0.000 n=29+29)
JSONEncode-4                194ms ± 0%     188ms ± 4%     ~     (p=0.417 n=23+30)
JSONDecode-4                890ms ± 5%     831ms ± 0%   -6.55%  (p=0.000 n=30+23)
Mandelbrot200-4            47.3ms ± 2%    46.5ms ± 0%     ~     (p=0.980 n=30+26)
GoParse-4                  43.1ms ± 6%    43.8ms ± 6%   +1.65%  (p=0.000 n=30+30)
RegexpMatchEasy0_32-4      1.06µs ± 0%    1.07µs ± 3%     ~     (p=0.092 n=23+30)
RegexpMatchEasy0_1K-4      5.53µs ± 0%    5.51µs ± 0%   -0.24%  (p=0.000 n=25+25)
RegexpMatchEasy1_32-4      1.02µs ± 3%    1.01µs ± 0%   -1.27%  (p=0.000 n=30+24)
RegexpMatchEasy1_1K-4      7.26µs ± 0%    7.33µs ± 0%   +0.95%  (p=0.000 n=23+26)
RegexpMatchMedium_32-4     1.84µs ± 7%    1.79µs ± 1%     ~     (p=0.333 n=30+23)
RegexpMatchMedium_1K-4      553µs ± 0%     547µs ± 0%   -1.14%  (p=0.000 n=24+22)
RegexpMatchHard_32-4       30.8µs ± 1%    30.3µs ± 0%   -1.40%  (p=0.000 n=24+24)
RegexpMatchHard_1K-4        928µs ± 0%     929µs ± 5%   +0.12%  (p=0.013 n=23+30)
Revcomp-4                   8.13s ± 4%     6.32s ± 1%  -22.23%  (p=0.000 n=30+23)
Template-4                  899ms ± 6%     854ms ± 1%   -5.01%  (p=0.000 n=30+24)
TimeParse-4                4.66µs ± 4%    4.59µs ± 1%   -1.57%  (p=0.000 n=30+23)
TimeFormat-4               4.58µs ± 0%    4.61µs ± 0%   +0.57%  (p=0.000 n=26+24)
[Geo mean]                  717µs          698µs        -2.55%

name                     old speed      new speed      delta
GobDecode-4              7.63MB/s ± 6%  8.08MB/s ± 5%   +5.88%  (p=0.000 n=30+30)
GobEncode-4              9.85MB/s ± 4%  9.75MB/s ± 6%   -1.04%  (p=0.000 n=30+30)
Gzip-4                   4.56MB/s ± 0%  4.55MB/s ± 4%   -0.36%  (p=0.003 n=24+30)
Gunzip-4                 45.3MB/s ± 1%  46.2MB/s ± 0%   +1.92%  (p=0.000 n=23+23)
JSONEncode-4             10.0MB/s ± 0%  10.4MB/s ± 4%     ~     (p=0.403 n=23+30)
JSONDecode-4             2.18MB/s ± 5%  2.33MB/s ± 0%   +6.91%  (p=0.000 n=30+23)
GoParse-4                1.34MB/s ± 5%  1.32MB/s ± 5%   -1.66%  (p=0.000 n=30+30)
RegexpMatchEasy0_32-4    30.2MB/s ± 0%  29.8MB/s ± 3%     ~     (p=0.099 n=23+30)
RegexpMatchEasy0_1K-4     185MB/s ± 0%   186MB/s ± 0%   +0.24%  (p=0.000 n=25+25)
RegexpMatchEasy1_32-4    31.4MB/s ± 3%  31.8MB/s ± 0%   +1.24%  (p=0.000 n=30+24)
RegexpMatchEasy1_1K-4     141MB/s ± 0%   140MB/s ± 0%   -0.94%  (p=0.000 n=23+26)
RegexpMatchMedium_32-4    541kB/s ± 6%   560kB/s ± 0%   +3.45%  (p=0.000 n=30+23)
RegexpMatchMedium_1K-4   1.85MB/s ± 0%  1.87MB/s ± 0%   +1.08%  (p=0.000 n=24+23)
RegexpMatchHard_32-4     1.04MB/s ± 1%  1.06MB/s ± 1%   +1.48%  (p=0.000 n=24+24)
RegexpMatchHard_1K-4     1.10MB/s ± 0%  1.10MB/s ± 5%   +0.15%  (p=0.004 n=23+30)
Revcomp-4                31.3MB/s ± 4%  40.2MB/s ± 1%  +28.52%  (p=0.000 n=30+23)
Template-4               2.16MB/s ± 6%  2.27MB/s ± 1%   +5.18%  (p=0.000 n=30+24)
[Geo mean]               7.57MB/s       7.79MB/s        +2.98%

fixes #24907

Change-Id: I94afd0e3f53d62a1cf5e452f3dd6daf61be21785
Reviewed-on: https://go-review.googlesource.com/107376
Run-TryBot: Cherry Zhang <cherryyz@google.com>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>

CL 99337 introduced a file with CRLF line endings. Convert them to LF
line endings as in all other Go files.

Change-Id: I68b28fd443f05bebbbd9280d1821c4ccd33a4a8a
Reviewed-on: https://go-review.googlesource.com/108075
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

Fixes #22874

Change-Id: Ia30fc8df39e88fbc2939a4490c34da8dd5815a94
GitHub-Last-Rev: 3ba7abcc96ee02837fbfd65c044326c2f1923020
GitHub-Pull-Request: golang/go#24307
Reviewed-on: https://go-review.googlesource.com/99337
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Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

Make comment example consistent with its description.
Fixes #24767

Change-Id: Icff54b489040b1ce66c644a21343c6576304cf75
Reviewed-on: https://go-review.googlesource.com/107663Reviewed-by: Rob Pike <r@golang.org>

This change provides VREV64 instruction for AES-GCM implementation.

Change-Id: Icdf278862b03556388586f459964b025c47b8c19
Reviewed-on: https://go-review.googlesource.com/107696Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Previously these examples declared "var v Value" but any caller would
need to write "var v atomic.Value", so we should use the external
package declaration form to avoid confusion about where Value comes
from.

Change-Id: Ic0b1a05fb6b700da61cfc8efca594c49a9bedb69
Reviewed-on: https://go-review.googlesource.com/107975Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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Use AT_TIMEKEEP ELF aux entry to access a kernel mapped ring of timehands structs.
The timehands are updated by the kernel periodically, but for accurate measure the
timecounter still needs to be queried.
Currently the fast path is used only when kern.timecounter.hardware==TSC-low
or kern.timecounter.hardware=='ARM MPCore Timecounter',
other timecounters revert back to regular system call.

TODO: add support for HPET timecounter on 386/amd64.

Change-Id: I321ca4e92be63ba21a2574b758ef5c1e729086ad
Reviewed-on: https://go-review.googlesource.com/93156
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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The current code encodes the register and the shift/extension into a.Offset
field and this is done in the frontend. The CL refactors it to have the
frontend record the register/shift/extension information in a.Reg or a.Index
and leave the encoding stuff for the backend.

Change-Id: I600f456aec95377b7b79cd58e94afcb30aca5d19
Reviewed-on: https://go-review.googlesource.com/106815Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
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Disasm.Decode currently always appends a tab to the formatted instruction,
although not to any relocations after it.

Decode has two clients: objdump and pprof.
pprof emits plain text, so it would be better not to have a trailing tab.
objdump wants the trailing tab for text/tabwriter,
but it is easy to add that to the Fprintf call.

Shifting the responsibility for the trailing tab to the caller
simplifies the code, increases correctness, and slightly improves
performance by reducing and coalescing string concatenations.

Change-Id: I0c85518ee185949e385de819e2e703bce757eba9
Reviewed-on: https://go-review.googlesource.com/106983
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
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This change adds vector multiply instructions to the assembler for
ppc64x.

Change-Id: I5143a2dc3736951344d43999066d38ab8be4a721
Reviewed-on: https://go-review.googlesource.com/107795Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #24831

Change-Id: Icd39093d1b7d9b25aa8374c0298cdb1dea48e672
Reviewed-on: https://go-review.googlesource.com/107817
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
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Reviewed-by: Andrew Bonventre <andybons@golang.org>

VDSO calls do manual stack alignment, which doesn't get tracked in the
pcsp table. Without accurate pcsp information, backtracing them is
dangerous, and causes a crash in the SIGPROF handler. Fortunately,
https://golang.org/cl/97315 saves a clean state in m.vdsoPC/SP. Change
to use those if they're present, without attempting a normal backtrace.

Fixes #24925

Change-Id: I4b8501ae73a9d18209e22f839773c4fe6102a509
Reviewed-on: https://go-review.googlesource.com/107778
Run-TryBot: Heschi Kreinick <heschi@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ia95643752d743d208363e3434497ffcf0af7b2d7
Reviewed-on: https://go-review.googlesource.com/107816
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

syslook cannot be called safely during SSA construction.

Change-Id: Ief173babd2e964fd5016578073dd3ba12e5731c5
Reviewed-on: https://go-review.googlesource.com/107815
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Instead issue a memory barrier on ARMv7 after reading the address.

Fixes #23777

Change-Id: I7aff2ab0246af64b437ebe0b31d4b30d351890d8
Reviewed-on: https://go-review.googlesource.com/94275Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
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Based on the code from https://github.com/riscv/riscv-go/ originally
written by Amol Bhave.

Change-Id: I8d5377096d4ff8b198dadb630511f9a0347f9797
Reviewed-on: https://go-review.googlesource.com/107339
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

There are no strange messages anymore, so define type MyBuffer in the
block where it is used.

Change-Id: Ic65b15dc76a40f6f734d9ac2116338502fbb66fd
Reviewed-on: https://go-review.googlesource.com/107735
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>

Some syscall structures used by crypto/x509 have uintptr
fields that store pointers. These pointers are set with
a pointer to another Go structure. But the pointers are
not visible by garbage collector, and GC does not update
the fields after they were set. So when structure with
invalid uintptr pointers passed to Windows, we get
memory corruption.

This CL introduces CertInfo, CertTrustListInfo and
CertRevocationCrlInfo types. It uses pointers to new types
instead of uintptr in CertContext, CertSimpleChain and
CertRevocationInfo.

CertRevocationInfo, CertChainPolicyPara and
CertChainPolicyStatus types have uintptr field that can
be pointer to many different things (according to Windows
API). So this CL introduces Pointer type to be used for
those cases.

As suggested by Austin Clements.

Fixes #21376
Updates #24820

Change-Id: If95cd9eee3c69e4cfc35b7b25b1b40c2dc8f0df7
Reviewed-on: https://go-review.googlesource.com/106275Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The escape analysis models the flow of "content" of X with a
level of "indirection" (OIND node) of X. This content can be
pointer dereference, or slice/string element. For the latter
case, the type of the OIND node should be the element type of
the slice/string. This CL fixes this. In particular, this
matters when the element type is pointerless, where the data
flow should not cause any escape.

Fixes #15730.

Change-Id: Iba9f92898681625e7e3ddef76ae65d7cd61c41e0
Reviewed-on: https://go-review.googlesource.com/107597Reviewed-by: David Chase <drchase@google.com>

Use bio.Reader. Include newline character in the expected string value
instead of truncating it. Get rid of weird "empty archive" check.

Passes toolstash-check.

Change-Id: I16e42542db4827e6ee3644b9a5540a4a30b9bc41
Reviewed-on: https://go-review.googlesource.com/107620
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The documentation for %v behavior for compound objects uses an ellipsis
to indicate indefinite lenght of elements. This is done for struct
fields as well as elements of arrays and slices. This adds the missing
ellipsis for maps.

Change-Id: Ia433387fe189d2daf5095df32085a541458f00a1
Reviewed-on: https://go-review.googlesource.com/107623Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

These fake imports are just so we can emit build dependencies for the
linker, so the package name isn't really necessary. Also, the package
import logic assumes that if we have the name for a package, then
we've already read some package data for it.

Using the empty string allows the importers to correctly populate it
the first time these packages are seen in package export data.

Passes toolstash-check.

Change-Id: I047bde297600e9dc07478fccc3f57ccc75ce8ae4
Reviewed-on: https://go-review.googlesource.com/107619
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This is already written out by printObjHeader in obj.go.

Change-Id: I23e7a3826a6233307bd591021718c4cf143b381c
Reviewed-on: https://go-review.googlesource.com/107618
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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This code will be useful for the indexed format importer, so break it
out to be easier to reuse separately.

Change-Id: Ie7e6b2ed89770e1ed9aa1edf11682fe35d6bb373
Reviewed-on: https://go-review.googlesource.com/107617
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

cmd/compile internally rewrites blank return parameters to "~bN". Add
a test to make sure this isn't exposed via the go/types API.

Change-Id: I319644dc5adf483ed30520fd8e9d88cf5cea9751
Reviewed-on: https://go-review.googlesource.com/107616
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #18037

Change-Id: I20e27bcc013b00b726eb348daf5ca86b138ddcc2
Reviewed-on: https://go-review.googlesource.com/107598
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

By using local variables and assigning them back to decompressor
at the end of huffSym, we allow compiler to keep them in registers
and avoid reloading/storing them repeatedly. To archive this,
moreBits was inlined and specialized to work with local variables.
Also move EOF error conversion to helper function, to make inlined
part of moreBits more readable. Together this results in nice speed-up:

name                             old time/op    new time/op    delta
Decode/Digits/Huffman/1e4-6         278µs ± 1%     240µs ± 2%  -13.72%  (p=0.000 n=10+10)
Decode/Digits/Huffman/1e5-6        2.38ms ± 1%    2.05ms ± 1%  -14.12%  (p=0.000 n=10+10)
Decode/Digits/Huffman/1e6-6        23.4ms ± 1%    19.9ms ± 0%  -14.69%  (p=0.000 n=9+9)
Decode/Digits/Speed/1e4-6           280µs ± 2%     254µs ± 1%   -9.28%  (p=0.000 n=10+9)
Decode/Digits/Speed/1e5-6          2.53ms ± 1%    2.35ms ± 1%   -7.17%  (p=0.000 n=10+10)
Decode/Digits/Speed/1e6-6          24.8ms ± 1%    23.0ms ± 1%   -7.22%  (p=0.000 n=10+10)
Decode/Digits/Default/1e4-6         281µs ± 2%     259µs ± 3%   -8.03%  (p=0.000 n=10+10)
Decode/Digits/Default/1e5-6        2.45ms ± 1%    2.30ms ± 1%   -6.15%  (p=0.000 n=10+10)
Decode/Digits/Default/1e6-6        24.1ms ± 1%    22.6ms ± 0%   -6.31%  (p=0.000 n=9+9)
Decode/Digits/Compression/1e4-6     279µs ± 2%     261µs ± 2%   -6.53%  (p=0.000 n=8+9)
Decode/Digits/Compression/1e5-6    2.44ms ± 1%    2.30ms ± 1%   -5.72%  (p=0.000 n=10+9)
Decode/Digits/Compression/1e6-6    24.0ms ± 1%    22.6ms ± 0%   -6.10%  (p=0.000 n=10+9)
Decode/Twain/Huffman/1e4-6          316µs ± 2%     267µs ± 3%  -15.30%  (p=0.000 n=9+10)
Decode/Twain/Huffman/1e5-6         2.62ms ± 0%    2.22ms ± 0%  -15.24%  (p=0.000 n=10+10)
Decode/Twain/Huffman/1e6-6         25.7ms ± 1%    21.8ms ± 0%  -15.19%  (p=0.000 n=10+10)
Decode/Twain/Speed/1e4-6            290µs ± 1%     264µs ± 2%   -9.17%  (p=0.000 n=9+10)
Decode/Twain/Speed/1e5-6           2.35ms ± 1%    2.13ms ± 1%   -9.74%  (p=0.000 n=9+10)
Decode/Twain/Speed/1e6-6           22.9ms ± 0%    20.7ms ± 0%   -9.68%  (p=0.000 n=10+9)
Decode/Twain/Default/1e4-6          270µs ± 2%     252µs ± 2%   -6.67%  (p=0.000 n=9+10)
Decode/Twain/Default/1e5-6         2.02ms ± 1%    1.84ms ± 1%   -8.85%  (p=0.000 n=10+10)
Decode/Twain/Default/1e6-6         19.1ms ± 0%    17.5ms ± 1%   -8.73%  (p=0.000 n=9+10)
Decode/Twain/Compression/1e4-6      272µs ± 1%     250µs ± 4%   -8.20%  (p=0.000 n=9+10)
Decode/Twain/Compression/1e5-6     2.01ms ± 0%    1.84ms ± 1%   -8.57%  (p=0.000 n=9+10)
Decode/Twain/Compression/1e6-6     19.1ms ± 0%    17.4ms ± 1%   -8.75%  (p=0.000 n=9+10)

name                             old speed      new speed      delta
Decode/Digits/Huffman/1e4-6      35.9MB/s ± 1%  41.7MB/s ± 2%  +15.91%  (p=0.000 n=10+10)
Decode/Digits/Huffman/1e5-6      41.9MB/s ± 1%  48.8MB/s ± 1%  +16.44%  (p=0.000 n=10+10)
Decode/Digits/Huffman/1e6-6      42.8MB/s ± 1%  50.2MB/s ± 0%  +17.22%  (p=0.000 n=9+9)
Decode/Digits/Speed/1e4-6        35.7MB/s ± 2%  39.4MB/s ± 1%  +10.22%  (p=0.000 n=10+9)
Decode/Digits/Speed/1e5-6        39.6MB/s ± 1%  42.6MB/s ± 1%   +7.73%  (p=0.000 n=10+10)
Decode/Digits/Speed/1e6-6        40.3MB/s ± 1%  43.4MB/s ± 1%   +7.78%  (p=0.000 n=10+10)
Decode/Digits/Default/1e4-6      35.6MB/s ± 2%  38.7MB/s ± 2%   +8.74%  (p=0.000 n=10+10)
Decode/Digits/Default/1e5-6      40.9MB/s ± 1%  43.6MB/s ± 1%   +6.55%  (p=0.000 n=10+10)
Decode/Digits/Default/1e6-6      41.5MB/s ± 1%  44.3MB/s ± 0%   +6.73%  (p=0.000 n=9+9)
Decode/Digits/Compression/1e4-6  35.8MB/s ± 2%  38.3MB/s ± 2%   +6.99%  (p=0.000 n=8+9)
Decode/Digits/Compression/1e5-6  40.9MB/s ± 1%  43.4MB/s ± 1%   +6.07%  (p=0.000 n=10+9)
Decode/Digits/Compression/1e6-6  41.6MB/s ± 1%  44.3MB/s ± 0%   +6.49%  (p=0.000 n=10+9)
Decode/Twain/Huffman/1e4-6       31.7MB/s ± 2%  37.4MB/s ± 3%  +18.08%  (p=0.000 n=9+10)
Decode/Twain/Huffman/1e5-6       38.2MB/s ± 0%  45.0MB/s ± 0%  +17.97%  (p=0.000 n=10+10)
Decode/Twain/Huffman/1e6-6       38.9MB/s ± 1%  45.9MB/s ± 0%  +17.90%  (p=0.000 n=10+10)
Decode/Twain/Speed/1e4-6         34.5MB/s ± 1%  38.0MB/s ± 2%  +10.11%  (p=0.000 n=9+10)
Decode/Twain/Speed/1e5-6         42.5MB/s ± 1%  47.0MB/s ± 1%  +10.79%  (p=0.000 n=9+10)
Decode/Twain/Speed/1e6-6         43.7MB/s ± 0%  48.3MB/s ± 0%  +10.72%  (p=0.000 n=10+9)
Decode/Twain/Default/1e4-6       37.1MB/s ± 2%  39.8MB/s ± 2%   +7.15%  (p=0.000 n=9+10)
Decode/Twain/Default/1e5-6       49.5MB/s ± 1%  54.3MB/s ± 1%   +9.71%  (p=0.000 n=10+10)
Decode/Twain/Default/1e6-6       52.3MB/s ± 0%  57.3MB/s ± 1%   +9.57%  (p=0.000 n=9+10)
Decode/Twain/Compression/1e4-6   36.7MB/s ± 1%  40.0MB/s ± 4%   +8.96%  (p=0.000 n=9+10)
Decode/Twain/Compression/1e5-6   49.8MB/s ± 0%  54.5MB/s ± 1%   +9.38%  (p=0.000 n=9+10)
Decode/Twain/Compression/1e6-6   52.3MB/s ± 0%  57.3MB/s ± 1%   +9.58%  (p=0.000 n=9+10)

Change-Id: Iabfd285535ddb210f7f48f33317c6463b5532400
Reviewed-on: https://go-review.googlesource.com/102235
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updates #23574

Change-Id: I1b87390679e0817a2f6e4e5938994ea32df87bd7
Reviewed-on: https://go-review.googlesource.com/107596Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>