This CL updates ParseFloat to recognize
standard hexadecimal floating-point constants.
See golang.org/design/19308-number-literals for background.

For #29008.

Change-Id: I45f3b0c36b5d92c0e8a4b35c05443a83d7a6d4b3
Reviewed-on: https://go-review.googlesource.com/c/160241
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: I15279e4aa9306bde925929907a7b5e7ef5d8b642
GitHub-Last-Rev: 6bc2d66aecd424b322ec0c23b280e74cb22e08c3
GitHub-Pull-Request: golang/go#30193
Reviewed-on: https://go-review.googlesource.com/c/162018Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ia546d3f0a12a3c3c291f7b6d5291193fdd47d7dd
Reviewed-on: https://go-review.googlesource.com/c/161966
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Permit shifts by non-constant signed integer shift counts.
Share logic for constant shift counts in non-constant
shifts and improve error messages a little bit.

R=Go1.13

Updates #19113.

Change-Id: Ia01d83ca8aa60a6a3f4c49f026e0c46396f852be
Reviewed-on: https://go-review.googlesource.com/c/159317
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

This CL introduces text/scanner support for the new binary and octal integer
literals, hexadecimal floats, and digit separators for all number literals.
The new code is closely mirroring the respective code for number literals in
cmd/compile/internal/syntax/scanner.go.

Uniformly use the term "invalid" rather than "illegal" in error messages
to match the respective error messages in the other scanners directly.

R=Go1.13

Updates #12711.
Updates #19308.
Updates #28493.
Updates #29008.

Change-Id: I2f291de13ba5afc0e530cd8326e6bf4c3858ebac
Reviewed-on: https://go-review.googlesource.com/c/161199
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The -asmhdr flag is used to generate header files for assembly code
such that that code has access to compile-time constants. During
the build these constants end up in the (ephemeral) file go_asm.h.

For historical reasons, floating-point and complex constants are
printed with a 'p' exponent but with decimal mantissa; also, because
of the compiler-internal precision of 512 bits, the mantissae are quite
large (and conversions are comparatively slow).

With the changes to the new Go 2 number literals, the respective
upcoming changes to text/scanner (which in turn is used by the assembler)
will make text/scanner newly accept hexadecimal floats; but also decimal
floats using the incorrect 'p' exponent and report an error in that case.

As a consequence, the assembler will report an error when trying to parse
the before-mentioned decimal floating-point values which are using 'p'
exponents. Since these constants are never needed in the assembly code,
do not emit them in the first place.

Change-Id: I06c7c96b04e8d062441120107992472f87a651b2
Reviewed-on: https://go-review.googlesource.com/c/161904
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Make sure Scanner.tokEnd is set before we call Scanner.Error
and update documentation accordingly.
(Until now tokEnd was only set before returning from Scan,
so a call to TokenText during error handling may have crashed.)

While at it, tighten a check in Scanner.TokenText to ensure
Scanner.tokEnd >= Scanner.tokPos if we have a token.

Also, silence error messages to Stderr in unrelated TestIllegalExponent.

Fixes #29723.

Change-Id: Ia97beeae91eaf9e0ed3dada0a806f1f7122461cc
Reviewed-on: https://go-review.googlesource.com/c/157819Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Rewrite non-decimal number prefixes to always use a lower-case base
("0X" -> "0x", etc.), and rewrite exponents to use a lower-case 'e'
or 'p'. Leave hexadecimal digits and 0-octals alone.

Comparing the best time of 3 runs of `time go test -run All` with
the time for a gofmt that doesn't do the rewrite shows no increase
in runtime for this bulk gofmt application (in fact on my machine
I see a small decline, probably due to cache effects).

R=Go1.13

Updates #12711.
Updates #19308.
Updates #29008.

Change-Id: I9c6ebed2ffa0a6a001c59412a73382090955f5a9
Reviewed-on: https://go-review.googlesource.com/c/160184Reviewed-by: Ian Lance Taylor <iant@golang.org>

This CL ensures that go/types can now handle the new
Go 2 number literals. The relevant changes enabling
them in go/types were made in go/constant in the CL
https://golang.org/cl/160239.

R=Go1.13

Updates #12711.
Updates #19308.
Updates #28493.
Updates #29008.

Change-Id: I45c1387198fac94769ac59c5301d86b4e1a1ff98
Reviewed-on: https://go-review.googlesource.com/c/160240Reviewed-by: Russ Cox <rsc@golang.org>

This CL introduces go/constant support for the new binary and octal integer
literals, hexadecimal floats, and digit separators for all number literals.

R=Go1.13

Updates #12711.
Updates #19308.
Updates #28493.
Updates #29008.

Change-Id: I7a55f91b8b6373ae6d98ba923b626d33c5552946
Reviewed-on: https://go-review.googlesource.com/c/160239Reviewed-by: Russ Cox <rsc@golang.org>

R=Go1.13

Updates #12711.
Updates #19308.
Updates #28493.
Updates #29008.

Change-Id: Icd25aa7f6e18ed671ea6cf2b1b292899daf4b1a5
Reviewed-on: https://go-review.googlesource.com/c/160018Reviewed-by: Russ Cox <rsc@golang.org>

This CL introduces go/scanner support for the new binary and octal integer
literals, hexadecimal floats, and digit separators for all number literals.
The new code is closely mirroring the respective code for number literals in
cmd/compile/internal/syntax/scanner.go.

R=Go1.13

Updates #12711.
Updates #19308.
Updates #28493.
Updates #29008.

Change-Id: I5315c6aaa7cfc41a618296be20e3acd5114d6b3c
Reviewed-on: https://go-review.googlesource.com/c/159997Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

This CL introduces compiler support for the new binary and octal integer
literals, hexadecimal floats, and digit separators for all number literals.

The new Go 2 number literal scanner accepts the following liberal format:

number   = [ prefix ] digits [ "." digits ] [ exponent ] [ "i" ] .
prefix   = "0" [ "b" |"B" | "o" | "O" | "x" | "X" ] .
digits   = { digit | "_" } .
exponent = ( "e" | "E" | "p" | "P" ) [ "+" | "-" ] digits .

If the number starts with "0x" or "0X", digit is any hexadecimal digit;
otherwise, digit is any decimal digit. If the accepted number is not valid,
errors are reported accordingly.

See the new test cases in scanner_test.go for a selection of valid and
invalid numbers and the respective error messages.

R=Go1.13

Updates #12711.
Updates #19308.
Updates #28493.
Updates #29008.

Change-Id: Ic8febc7bd4dc5186b16a8c8897691e81125cf0ca
Reviewed-on: https://go-review.googlesource.com/c/157677Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

The current implementation accepted binary exponents but restricted
them to 'p'. This change permits both 'p' and 'P'.

R=Go1.13

Updates #29008.

Change-Id: I7a89ccb86af4438f17b0422be7cb630ffcf43272
Reviewed-on: https://go-review.googlesource.com/c/159297Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

Make it possible to "unread" more than one byte before the most
recently read rune. Use a better name than ungetr2 and make it
slightly more efficient.

R=Go1.13

Change-Id: I45d5dfa11e508259a972ca6560d1f78d7a51fe15
Reviewed-on: https://go-review.googlesource.com/c/158957Reviewed-by: Russ Cox <rsc@golang.org>

Fixes #30166

Change-Id: I4704b57ed48197f512cd1b818e1f7d2fffc0d9ce
Reviewed-on: https://go-review.googlesource.com/c/161898
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

install.html still insisted that GOROOT must be set if a binary install
of Go is set up in a custom directory. However, since 1.10, this has
been unnecessary as the GOROOT will be found based on the location of
the 'go' binary being run.

Likewise, install-source.html includes an 'export GOROOT' line in a
section that only talks about explicitly setting GOARCH and GOOS, which
is optional. We don't want to have users think it is recommended to set
GOROOT here either, so remove the unnecessary line.

Change-Id: I7dfef09f9a1d003e0253b793d63ea40d5cf1837f
Reviewed-on: https://go-review.googlesource.com/c/161758Reviewed-by: Andrew Bonventre <andybons@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>

runtime/internal/atomic/atomic_mipsx.go enforces 64-bit alignment.

Change-Id: Ifdc36e1c0322827711425054d10f1c52425a13fa
Reviewed-on: https://go-review.googlesource.com/c/161697
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I46046cddceff2d44a7b2517db1ebf7acdf5f2b90
GitHub-Last-Rev: 7fb9f26476d2764f07d068ce612bf79b1e7f44b4
GitHub-Pull-Request: golang/go#30144
Reviewed-on: https://go-review.googlesource.com/c/161718Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

When prepared on a DB, prepared statement code in database/sql handles everything to keep the prepared statement alive as it moves across the connection pool. Understanding this is an important part of using this API correctly, but it was only documented indirectly via `(*Tx) Prepare*`.

Change-Id: Ic8757e0150d59e675d9f0252f6c15aef2cc2e831
GitHub-Last-Rev: 55dba87458542cb631baac80aeea0c3607d8f421
GitHub-Pull-Request: golang/go#29890
Reviewed-on: https://go-review.googlesource.com/c/159077Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Daniel Theophanes <kardianos@gmail.com>

Most of the issues that led to the decision on #30055 were related to
incompatibility with or faulty support for RSA-PSS (#29831, #29779,
v1.5 signatures). RSA-PSS is required by TLS 1.3, but is also available
to be negotiated in TLS 1.2.

Altering TLS 1.2 behavior based on GODEBUG=tls13=1 feels surprising, so
just disable RSA-PSS entirely in TLS 1.2 until TLS 1.3 is on by default,
so breakage happens all at once.

Updates #30055

Change-Id: Iee90454a20ded8895e5302e8bcbcd32e4e3031c2
Reviewed-on: https://go-review.googlesource.com/c/160998
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>

Updates #30055

Change-Id: If68615c8e9daa4226125dcc6a6866f29f3cfeef1
Reviewed-on: https://go-review.googlesource.com/c/160997
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

If a certificate somehow has an AKID, it should still chain successfully
to a parent without a SKID, even if the latter is invalid according to
RFC 5280, because only the Subject is authoritative.

This reverts to the behavior before #29233 was fixed in 77013065. Roots
with the right subject will still be shadowed by roots with the right
SKID and the wrong subject, but that's been the case for a long time, and
is left for a more complete fix in Go 1.13.

Updates #30079

Change-Id: If8ab0179aca86cb74caa926d1ef93fb5e416b4bb
Reviewed-on: https://go-review.googlesource.com/c/161097Reviewed-by: Adam Langley <agl@golang.org>

Change-Id: Idee94a1d93555d53442098dd7479982e3f5afbba
Reviewed-on: https://go-review.googlesource.com/c/161339Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: If3bab2dd5278ebc621235164e9d6ff710ba326ee
Reviewed-on: https://go-review.googlesource.com/c/160898Reviewed-by: Adam Langley <agl@golang.org>

Change-Id: Ia830f59d6f6ca1bc506ec298ccfc154d9f94f01d
GitHub-Last-Rev: 3ab18d4fd1a8d4295713cbb7ff74f30b3838b6d3
GitHub-Pull-Request: golang/go#30067
Reviewed-on: https://go-review.googlesource.com/c/160829
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #22447
Fixes #22448

Change-Id: Ia24f42c31e014c79040ff927f1247dfb2318de4f
Reviewed-on: https://go-review.googlesource.com/c/160778Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>

Expand modules documentation to clarify why @none is useful. The
wording is the one suggested by rsc on the issue.

Fixes #26684

Change-Id: I76dc4ff87e50f1dd8536fd9ac1fd938adb29bee3
Reviewed-on: https://go-review.googlesource.com/c/161037Reviewed-by: Bryan C. Mills <bcmills@google.com>

Change-Id: Ib0a0d04aaaaa3c213fdb8646bd9b7dfdadae40d4
Reviewed-on: https://go-review.googlesource.com/c/160831Reviewed-by: Filippo Valsorda <filippo@golang.org>

Fixes #30065

Change-Id: I3d0fb03bab397548653d5f3b386cfe2980ac1030
Reviewed-on: https://go-review.googlesource.com/c/160830
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Make sure the argument to memmove is of pointer type before we try to
get the element type.

This has been noticed for code that uses unsafe+linkname so it can
call runtime.memmove. Probably not the best thing to allow, but the
code is out there and we'd rather not break it unnecessarily.

Fixes #30061

Change-Id: I334a8453f2e293959fd742044c43fbe93f0b3d31
Reviewed-on: https://go-review.googlesource.com/c/160826
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

We are copying the results to uninitialized stack space. Write
barrier is not needed.

Fixes #30041.

Change-Id: Ia91d74dbafd96dc2bd92de0cb479808991dda03e
Reviewed-on: https://go-review.googlesource.com/c/160737
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

Fixes #30043

Change-Id: I4ecfff7d8a9432240c1927f7484786fe1182b773
Reviewed-on: https://go-review.googlesource.com/c/160797Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

CL 159859 causes build failure with old clang versions (3.4.1) on FreeBSD 10.3/10.4.

Update #29962
Update #27619

Change-Id: I78264ac5d8d17eeae89a982e89aac988eb22b286
Reviewed-on: https://go-review.googlesource.com/c/160777
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

When scavenging small amounts it's possible we over-scavenge by a
significant margin since we choose to scavenge the largest spans first.
This over-scavenging is never accounted for.

With this change, we add a scavenge credit pool, similar to the reclaim
credit pool. Any time scavenging triggered by RSS growth starts up, it
checks if it can cash in some credit first. If after using all the
credit it still needs to scavenge, then any extra it does it adds back
into the credit pool.

This change mitigates the performance impact of golang.org/cl/159500 on
the Garbage benchmark. On Go1 it suggests some improvements, but most of
that is within the realm of noise (Revcomp seems very sensitive to
GC-related changes, both postively and negatively).

Garbage: https://perf.golang.org/search?q=upload:20190131.5
Go1:     https://perf.golang.org/search?q=upload:20190131.4

Performance change with both changes:

Garbage: https://perf.golang.org/search?q=upload:20190131.7
Go1:     https://perf.golang.org/search?q=upload:20190131.6

Change-Id: I87bd3c183e71656fdafef94714194b9fdbb77aa2
Reviewed-on: https://go-review.googlesource.com/c/160297Reviewed-by: Austin Clements <austin@google.com>

Because scavenged and unscavenged spans no longer coalesce, memory that
is freed no longer has a high likelihood of being re-scavenged. As a
result, if an application is allocating at a fast rate, it may work fast
enough to undo all the scavenging work performed by the runtime's
current scavenging mechanisms. This behavior is exacerbated by the
global best-fit allocation policy the runtime uses, since scavenged
spans are just as likely to be chosen as unscavenged spans on average.

To remedy that, we treat each allocation of scavenged space as a heap
growth, and scavenge other memory to make up for the allocation.

This change makes performance of the runtime slightly worse, as now
we're scavenging more often during allocation. The regression is
particularly obvious with the garbage benchmark (3%) but most of the Go1
benchmarks are within the margin of noise. A follow-up change should
help.

Garbage: https://perf.golang.org/search?q=upload:20190131.3
Go1:     https://perf.golang.org/search?q=upload:20190131.2

Updates #14045.

Change-Id: I44a7e6586eca33b5f97b6d40418db53a8a7ae715
Reviewed-on: https://go-review.googlesource.com/c/159500Reviewed-by: Austin Clements <austin@google.com>

GCC 9 has started emitting warnings when taking the address of a field
in a packed struct may cause a misaligned pointer. We use packed
structs in cgo to ensure that our field layout matches the C
compiler's layout. Our pointers are always aligned, so disable the warning

Fixes #29962

Change-Id: I7e290a7cf694a2c2958529e340ebed9fcd62089c
Reviewed-on: https://go-review.googlesource.com/c/159859
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

This update has been automatically generated using the updatecontrib
command at CL 160277:

	cd gotip
	go run golang.org/x/build/cmd/updatecontrib

Actions taken (relative to CONTRIBUTORS at origin/master):

	Added Aaron Cannon <cannona@fireantproductions.com>
	Added Andzej Maciusovic <andzej.maciusovic@gmail.com>
	Added Douglas Danger Manley <doug.manley@gmail.com>
	Added Federico Bond <federicobond@gmail.com>
	Added Frew Schmidt <github@frew.co>
	Added GitHub User @saitarunreddy (21041941) <saitarunreddypalla@gmail.com>
	Added GitHub User @tell-k (26263) <ffk2005@gmail.com>
	Added Guilherme Caruso <gui.martinscaruso@gmail.com>
	Added Jay Taylor <outtatime@gmail.com>
	Added Juan Pablo Civile <elementohb@gmail.com>
	Added Julien Kauffmann <julien.kauffmann@freelan.org>
	Added Maya Rashish <maya@NetBSD.org>
	Added Parminder Singh <parmsingh101@gmail.com>
	Added Peter Dotchev <dotchev@gmail.com>
	Added Quinten Yearsley <qyearsley@chromium.org>
	Added Ross Smith II <ross@smithii.com>
	Added Sean Chen <oohcode@gmail.com>
	Added Sebastiaan van Stijn <github@gone.nl>
	Added Sebastian Schmidt <yath@google.com>
	Added Sebastien Williams-Wynn <sebastien@cytora.com>
	Added Viacheslav Poturaev <vearutop@gmail.com>
	Added Yohei Takeda <yo.tak0812@gmail.com>
	Used GitHub User @saitarunreddy (21041941) form for saitarunreddy <saitarunreddypalla@gmail.com> https://github.com/golang/build/commit/269e03a [build]
	Used GitHub User @tell-k (26263) form for tell-k <ffk2005@gmail.com> https://github.com/golang/tools/commit/85a87a81 [tools]
	Used GitHub name "Akhil Indurti" for smasher164 <aindurti@gmail.com> https://github.com/golang/go/commit/a7af474359 [build go]
	Used GitHub name "Guilherme Caruso" for GuilhermeCaruso <gui.martinscaruso@gmail.com> https://github.com/golang/go/commit/5fae09b738 [go]
	Used GitHub name "Ivan Markin" for nogoegst <nogoegst@users.noreply.github.com> https://github.com/golang/go/commit/a1addf15df [go]
	Used GitHub name "Keiji Yoshida" for yosssi <yoshida.keiji.84@gmail.com> https://github.com/golang/lint/commit/ac6833c [lint]
	Used GitHub name "Marwan Sulaiman" for marwan-at-work <marwan.sameer@gmail.com> https://github.com/golang/go/commit/92caeef892 [go]
	Used GitHub name "Michalis Kargakis" for kargakis <mkargaki@redhat.com> https://github.com/golang/go/commit/e243d242d7 [go]
	Used GitHub name "Robin Eklind" for mewmew <rnd0x00@gmail.com> https://github.com/golang/go/commit/b8620afb8d [go proposal.git]
	Used GitHub name "Sean Chen" for two <oohcode@gmail.com> https://github.com/golang/sys/commit/302c3dd [sys]
	Used GitHub name "Sebastien Williams-Wynn" for GiantsLoveDeathMetal <sebastien@cytora.com> https://github.com/golang/go/commit/4e056ade24 [go]
	Used GitHub name "Yohei Takeda" for yo-tak <yo.tak0812@gmail.com> https://github.com/golang/go/commit/8b7cf898af [go]

Given that the scope of updatecontrib is only to add contributors to
CONTRIBUTORS file, without having to check CLAs or deal with legal
matters, we can relax the requirement of having a space in the name
before it gets added to the CONTRIBUTORS file. That will be done
in a later change.

Updates #12042

Change-Id: I70248f3c82a836ee829256898e931e638ee45eb4
Reviewed-on: https://go-review.googlesource.com/c/160261Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Note the removal of the go tool tour command in the Go 1.12 release
notes.

Updates #24819

Change-Id: I258ab9401ea2cc06a83328c67299376fcf23c980
Reviewed-on: https://go-review.googlesource.com/c/158618Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

Fixes #29983

Change-Id: I24077bde991e621c23d00973b2a77bb3a18e4ae7
Reviewed-on: https://go-review.googlesource.com/c/160180
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>