Allows reading -importmap options from a file instead of putting
them all on the command line, and adds the ability to specify the
file location of specific packages. In effect, -importcfg is a generalization
of and supersedes -importmap, -importsuffix, and -I.
Of course, those flags will continue to be supported,
for compatibility with other tools.

Having this flag in Go 1.9 will let us try some experiments involving
package management without needing guinea pigs to build a
custom Go toolchain.

This flag also helps with #14271 at some later point.

For #20579.

Change-Id: If005dbc2b01d8fd16cbfd3687dfbe82499f4bc56
Reviewed-on: https://go-review.googlesource.com/44850
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #18991.

Change-Id: I46ded007b0c6a6e1173a55f3938007ab3a928dd9
Reviewed-on: https://go-review.googlesource.com/44858
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

Apparently people get confused by the fact that

  Split("", ",")

returns []{""} instead of []{}.

This is actually just a consequence of the fact that if the separator
sep (2nd argument) is not found the string s (1st argument), then the
Split* functions return a length 1 slice with the string s in it.

Document the general case: if sep is not in s, what you get is a len 1
slice with s in it; unless both s and sep are "", in that case you get
an empty slice of length 0.

Fixes #19726

Change-Id: I64c8220b91acd1e5aa1cc1829199e0cd8c47c404
Reviewed-on: https://go-review.googlesource.com/44950Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

Try to avoid a race between the main goroutine exiting and a panic
occurring. Don't try too hard, to avoid hanging.

Updates #3934
Fixes #20018

Change-Id: I57a02b6d795d2a61f1cadd137ce097145280ece7
Reviewed-on: https://go-review.googlesource.com/41052Reviewed-by: Austin Clements <austin@google.com>

Make sure that in complex division we reject divisors that would
underflow to zero when using the textbook complex-division method we
currently use.

This change does for go/types what golang.org/cl/42650 did for gc.

Fixes #20227

Change-Id: Iaa784ac5e60141f51c501eb0e3ce0e9c1c2993d0
Reviewed-on: https://go-review.googlesource.com/44590
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

C code expects CR2, CR3, and CR4 to be preserved across function calls.
Preserve the entire CR register across function calls in
_rt0_ppc64le_linux_lib and crosscall2. The standard ppc64le call frame
uses 8(R1) as the place to save CR; emulate that.

It's hard to write a reliable test for this as it requires writing C
code that sets CR2, CR3, or CR4 across a call to a Go function.

Change-Id: If39e771a5b574602b848227312e83598fe74eab7
Reviewed-on: https://go-review.googlesource.com/44733
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>

The MOVFL instruction (which external PPC64 docs call mtcrf) can take
either a CR register or a constant. It doesn't make sense to specify
both, as the CR register implies the constant value. Specifying either
a register or a constant is enforced by the implementation in the
asmout method (case 69).

However, the optab was providing a form that specified both a constant
and a CR register, and was not providing a form that specified only a
constant. This CL fixes the optab table to provide a form that takes
only a constant.

No test because I don't know where to write it. The next CL in this
series will use the new instruction format.

Change-Id: I8bb5d3ed60f483b54c341ce613931e126f7d7be6
Reviewed-on: https://go-review.googlesource.com/44732
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>

Programs built from N libraries required O(N²) time to do the
deduplication checks, even if there were never any duplicates.
In most programs N is small enough not to worry, but this may
affect large programs.

Noticed by inspection, not any specific bug report.

Fixes #20578.

Change-Id: Ic4108f1058be39da990a79b1e0b8ce95fde44cef
Reviewed-on: https://go-review.googlesource.com/44852
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I4c579d0d02f6c9cbef1dc2bc2c93cff614538dea
Reviewed-on: https://go-review.googlesource.com/44854
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Otherwise removing a .f file won't trigger a rebuild.
Noticed by inspection while working on the code.
I don't have a good way to write a test for this,
and I expect the code to change significantly in the next
release, but might as well get it right for Go 1.9.

Change-Id: I3f6f9f71b3a7d4f0be49a47419dac59899959e7c
Reviewed-on: https://go-review.googlesource.com/44855
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Close any Rows queried within a Tx when the Tx is closed. This prevents
the Tx from blocking on rollback if a Rows query has not been closed yet.

Fixes #20575

Change-Id: I4efe9c4150e951d8a0f1c40d9d5e325964fdd608
Reviewed-on: https://go-review.googlesource.com/44812Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This is another attempt at the change attempted in
https://golang.org/cl/27117 and rolled back in https://golang.org/cl/34134

The difference between this and the previous attempt is that this version only
retries if the new field GetBody is set on the Request.

Additionally, this allows retries of requests with idempotent methods even if
they have bodies, as long as GetBody is defined.

This also fixes an existing bug where readLoop could make a redundant call to
setReqCanceler for DELETE/POST/PUT/etc requests with no body with zero bytes
written.

This clarifies the existing TestRetryIdempotentRequestsOnError test (and changes
it into a test with 4 subtests).  When that test was written, it was in fact
testing "retry idempotent requests" logic, but the logic had changed since then,
and it was actually testing "retry requests with no body when no bytes have been
written". (You can confirm this by changing the existing test from a GET to a
DELETE; it passes without the changes in this CL.) We now test for the no-Body
and GetBody cases for both idempotent and nothing-written-non-idempotent
requests.

Fixes #18241
Fixes #17844

Change-Id: I69a48691796f6dc08c31f7aa7887b7dfd67e278a
Reviewed-on: https://go-review.googlesource.com/42142
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

There are two issues in constant decomposition.

1. A typo in "func immrot2s" blocks "case 107" of []optab be triggered.

2. Though "ADD $0xffff, R0, R0" is decomposed to "ADD $0xff00, R0, R0" and
   "ADD $0x00ff, R0, R0" as expected, "ADD $0xffff, R0" still uses the
   constant pool, which should be the same as "ADD $0xffff, R0, R0".

This patch fixes them and adds more instruction encoding tests.

fix #20516

Change-Id: Icd7bdfa1946b29db15580dcb429111266f1384c6
Reviewed-on: https://go-review.googlesource.com/44335
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Fixes #19526

Change-Id: Ifaaf454e0e89fdf4309118c2e2e6ac0d0a43c39d
Reviewed-on: https://go-review.googlesource.com/44711Reviewed-by: Ian Lance Taylor <iant@golang.org>

Replace int division with (cheaper) byte division in heapBitsSetType.
Provides noticeable speed-up:

GrowSlicePtr-6   181ns ± 3%   169ns ± 3%  -6.85%  (p=0.000 n=10+10)

Change-Id: I4064bb72e8e692023783b8f58d19491844c39382
Reviewed-on: https://go-review.googlesource.com/42290
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Since TestPingPongHog tests the scheduler, it's ultimately
probabilistic. Currently, it requires the result be at most of factor
of 2 off of the ideal. It turns out this isn't quite enough in
practice, with factors on 1000 iterations on linux/amd64 ranging from
0.48 to 2.5. If the test were failing, we would expect a factor closer
to 1000X, so it's pretty safe to expand the accepted factor from 2 to
5.

Fixes #20494.

Change-Id: If8f2e96194fe66f1fb981a965d1167fe74ff38d7
Reviewed-on: https://go-review.googlesource.com/44859
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #17625

Change-Id: I09319b888b547c631a50dbfab9255cc08e8a2426
Reviewed-on: https://go-review.googlesource.com/40691Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

I learned from CL 41770 that valState’s size
matters to compiler performance.
Encode that knowledge in a test.

Change-Id: I7c0fde6a4cf460017619dbcce1c1ddaa7af10239
Reviewed-on: https://go-review.googlesource.com/44737
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

For test.go:

	package main

	import (
	   "C"
	   "fmt"
	)

	func main() {
		 fmt.Println("Hello, world!")
		 C.no_such_f()
	}

Before:

	could not determine kind of name for C.no_such_f

After:

	./test.go:10:2: could not determine kind of name for C.no_such_f

Fixes #18452

Change-Id: I49c136b7fa60fab25d2d5b905d440fe4d106e565
Reviewed-on: https://go-review.googlesource.com/34783
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I98d265bfa4f5944360d0258d2cb6bbc78010c708
Reviewed-on: https://go-review.googlesource.com/44731Reviewed-by: Ian Lance Taylor <iant@golang.org>

1) Split atLineBegin into its two components: writing of // line directives
and writing of indentation (no functionality changes).

2) Don't call writeLineDirective at the beginning of a line if we're
writing white space - it's not necessary. This is the bug fix.

3) Move testing of the SourcePos mode out of writeLineDirective and
into the (single) caller. Clearer and more efficient.

(Instead of these 3 changes one could also have simply called the
original atLineBegin with position p.out rather than p.pos. This
would have caused atLineBegin to not write a line directive.
Factoring the code seemed like a cleaner and more direct approach.)

Fixes #5945.

Change-Id: Ia8710806b6d3d4e5044116b142c036a4ab5a1764
Reviewed-on: https://go-review.googlesource.com/44651Reviewed-by: Alan Donovan <adonovan@google.com>

Fixes #19383

Change-Id: Ic84517053ced7794006f6fc65e6f249e97d6cf35
Reviewed-on: https://go-review.googlesource.com/44691Reviewed-by: Ian Lance Taylor <iant@golang.org>

Defaulting total to 1 for each function, adds up to the
counting error. testing/cover.go already does this once.

Fixes #20515

Change-Id: I0e3f524c2ccb628eb9a8f0a1f81c22365c24cf9a
Reviewed-on: https://go-review.googlesource.com/44337
Run-TryBot: Dhananjay Nakrani <dhananjayn@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Arguments to inlined calls are hidden from setPos as follows:

    args := as.Rlist
    as.Rlist.Set(nil)
    // setPos...
    as.Rlist.Set(args.Slice())

Previously, this code had no effect since the value of as was
overwritten by the assignment in the retvars loop.

Fixes #19799.

Change-Id: Iaf97259f82fdba8b236136337cc42b2774c7fef5
Reviewed-on: https://go-review.googlesource.com/44351
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

The test no longer passes as of https://golang.org/cl/43777, which
intentionally disables the feature that this test was checking for.
Nobody noticed since the test is not run in -short mode.

Updates #20435.

Change-Id: I64f37fd94c01f22ead88470b6d9bfe8a151ddb1c
Reviewed-on: https://go-review.googlesource.com/44650Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>

Fixes #20551

Change-Id: Ia47cae14a26fe5f278ad7209218d083cc50a3ff8
Reviewed-on: https://go-review.googlesource.com/44572Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates #20540

Change-Id: I864008fadd77b0aeb10fe7e7f1ec696516a5add5
Reviewed-on: https://go-review.googlesource.com/44492Reviewed-by: Robert Griesemer <gri@golang.org>

Currently we inline array comparisons for arrays with at most 4 elements.
Compare arrays with small size, but more than 4 elements (e. g. [16]byte)
with larger compares. This provides very slightly smaller binaries,
and results in faster code.

ArrayEqual-6  7.41ns ± 0%  3.17ns ± 0%  -57.15%  (p=0.000 n=10+10)

For go tool:
global text (code) = -559 bytes (-0.014566%)

This also helps mapaccess1_faststr, and maps in general:

MapDelete/Str/1-6               195ns ± 1%     186ns ± 2%   -4.47%  (p=0.000 n=10+10)
MapDelete/Str/2-6               211ns ± 1%     177ns ± 1%  -16.01%  (p=0.000 n=10+10)
MapDelete/Str/4-6               225ns ± 1%     183ns ± 1%  -18.49%  (p=0.000 n=8+10)
MapStringKeysEight_16-6        31.3ns ± 0%    28.6ns ± 0%   -8.63%  (p=0.000 n=6+9)
MapStringKeysEight_32-6        29.2ns ± 0%    27.6ns ± 0%   -5.45%  (p=0.000 n=10+10)
MapStringKeysEight_64-6        29.1ns ± 1%    27.5ns ± 0%   -5.46%  (p=0.000 n=10+10)
MapStringKeysEight_1M-6        29.1ns ± 1%    27.6ns ± 0%   -5.49%  (p=0.000 n=10+10)

Change-Id: I9ec98e41b233031e0e96c4e13d86a324f628ed4a
Reviewed-on: https://go-review.googlesource.com/40771
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

This includes the patch for systems that build PIE executables by
defaul

Updates #20276.

Change-Id: Iecf8dfcf11bc18d397b8075559c37e3610f825cb
Reviewed-on: https://go-review.googlesource.com/44470Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #20540

Change-Id: I440eee02d37b6921613f9ae77875d91eeec48b1e
Reviewed-on: https://go-review.googlesource.com/44490Reviewed-by: Robert Griesemer <gri@golang.org>

Apply the fix in CL 44355 to MIPS.

ARM64 has these rules but commented out for performance reason.
Fix the commented rules, in case they are enabled in the future.

Enhance the test so it triggers the failure on ARM and MIPS without
the fix.

Updates #20530.

Change-Id: I82d77448e3939a545fe519d0a29a164f8fa5417c
Reviewed-on: https://go-review.googlesource.com/44430
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

Fixes #20490

Change-Id: I9cfa604f9ff94df779cb9b4cbbd706258fc473ac
Reviewed-on: https://go-review.googlesource.com/44150
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

The current implementation of forkAndExecInChild for Linux does not allow
spawned processes steal the controlling terminal from a different session
group. This patch passes 1 as the argument to TIOCSCTTY in order to allow
spawned processes steal controlling terminals.

Fixes #20454

Change-Id: I171b8981509d648b07f89bddc1e9d45cb70e00e6
Reviewed-on: https://go-review.googlesource.com/44343Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Block signals explicitly during lwp_create since blocking via
the context does not work.

This was originally added in pkgsrc as
http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/lang/go/patches/patch-src_runtime_os__netbsd.go?rev=1.1

Fixes #19295.

Change-Id: I431e70c047cff446e9cfc20d356f45df98c63487
Reviewed-on: https://go-review.googlesource.com/41350Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This should help narrowing down the possible cause of #20514.

Updates #20514.

Change-Id: Ie997400c9749aace7783bd585b23dbb4cefc181d
Reviewed-on: https://go-review.googlesource.com/44375Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #20529

Change-Id: I3cb0c037b1737fbc3fa3b1b61ed8a42cfaf8e10d
Reviewed-on: https://go-review.googlesource.com/44344
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Replacing byteload-of-bytestore-of-x with x is incorrect
when x contains a larger-than-byte value (and so on for
16 and 32-bit load/store pairs).  Replace "x" with the
appropriate zero/sign extension of x, which if unnecessary
will be repaired by other rules.

Made logic for arm match x86 and amd64; yields minor extra
optimization, plus I am (much) more confident it's correct,
despite inability to reproduce bug on arm.

Ppc64 lacks this optimization, hence lacks this problem.

See related https://golang.org/cl/37154/
Fixes #20530.

Change-Id: I6af9cac2ad43bee99cafdcb04725ce7e55a43323
Reviewed-on: https://go-review.googlesource.com/44355
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

Fixes #20394

Change-Id: Iabb2a53fd1ddb783e7fb5b60ced8482c2e2569c4
Reviewed-on: https://go-review.googlesource.com/44377
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Replaced ../gc/reflect.c with
cmd/compile/internal/gc/reflect.go.

Fixes #20525

Change-Id: Ibafd36ea446ace5c677df27873a4bbf716a0a9bc
Reviewed-on: https://go-review.googlesource.com/44376Reviewed-by: Ian Lance Taylor <iant@golang.org>

Updates golang_org/x/net/lif to rev fcc8ed8 for:
- lif: rename internal types (http://golang.org/cl/43070)

Change-Id: I0aad9a8b504d673b29d3c26b3717ffa8512e0cdf
Reviewed-on: https://go-review.googlesource.com/44392Reviewed-by: Ian Lance Taylor <iant@golang.org>