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24773 Commits

Author SHA1 Message Date
Josh Bleecher Snyder
e5fe33e546 [dev.ssa] cmd/compile: respect phi values in tighten
Given (say)

b1: <- b2 b3
  v1 = Phi <t> v2 v3
b2:
  v2 = ...
b3:
  ...

tighten will move v2 to b1, since it is only used in b1.

This is wrong; v2 needs to be evaluated before entering b1.
Fix it.

Change-Id: I2cc3b30e3ffd221cf594e36cec534dfd9cf3c6a7
Reviewed-on: https://go-review.googlesource.com/13264
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-06 17:07:14 +00:00
Russ Cox
fced03a5c6 net/url: allow all valid host chars in RawPath
The old code was only allowing the chars we choose not to escape.
We sometimes prefer to escape chars that do not strictly need it.
Allowing those to be used in RawPath lets people override that
preference, which is in fact the whole point of RawPath (new in Go 1.5).

While we are here, also allow [ ] in RawPath.
This is not strictly spec-compliant, but it is what modern browers
do and what at least some people expect, and the [ ] do not cause
any ambiguity (the usual reason they would be escaped, as they are
part of the RFC gen-delims class).
The argument for allowing them now instead of waiting until Go 1.6
is that this way RawPath has one fixed meaning at the time it is
introduced, that we should not need to change or expand.

Fixes #5684.

Change-Id: If9c82a18f522d7ee1d10310a22821ada9286ee5c
Reviewed-on: https://go-review.googlesource.com/13258
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-06 02:59:16 +00:00
Russ Cox
e8be9a170c net/url: do not percent-encode valid host characters
The code in question was added as part of allowing zone identifiers
in IPv6 literals like http://[ipv6%zone]:port/foo, in golang.org/cl/2431.

The old condition makes no sense. It refers to §3.2.1, which is the wrong section
of the RFC, it excludes all the sub-delims, which §3.2.2 (the right section)
makes clear are valid, and it allows ':', which is not actually valid,
without an explanation as to why (because we keep :port in the Host field
of the URL struct).

The new condition allows all the sub-delims, as specified in RFC 3986,
plus the additional characters [ ] : seen in IP address literals and :port suffixes,
which we also keep in the Host field.

This allows mysql://a,b,c/path to continue to parse, as it did in Go 1.4 and earlier.

This CL does not break any existing tests, suggesting the over-conservative
behavior was not intended and perhaps not realized.

It is especially important not to over-escape the host field, because
Go does not unescape the host field during parsing: it rejects any
host field containing % characters.

Fixes #12036.

Change-Id: Iccbe4985957b3dc58b6dfb5dcb5b63a51a6feefb
Reviewed-on: https://go-review.googlesource.com/13254
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
2015-08-06 02:55:37 +00:00
Mikio Hara
91e3b35168 doc/go1.5.html: fix typo
Change-Id: Ic61fd38e7d2e0821c6adcaa210199a7dae8849a7
Reviewed-on: https://go-review.googlesource.com/13281
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-06 02:55:27 +00:00
Russ Cox
fc22331ccd net/url: restrict :port checking to [ipv6]:port form
Go 1.4 and earlier accepted mysql://x@y(z:123)/foo
and I don't see any compelling reason to break that.

The CL during Go 1.5 that broke this syntax was
trying to fix #11208 and was probably too aggressive.
I added a test case for #11208 to make sure that stays
fixed.

Relaxing the check did not re-break #11208 nor did
it cause any existing test to fail. I added a test for the
mysql://x@y(z:123)/foo syntax being preserved.

Fixes #12023.

Change-Id: I659d39f18c85111697732ad24b757169d69284fc
Reviewed-on: https://go-review.googlesource.com/13253
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
2015-08-06 02:55:03 +00:00
Andrew Gerrand
e38c801ad1 A+C: add Andy Maloney
Fixes #10639

Change-Id: I0aa3bcbf656e23e6a110041439f6052057074b88
Reviewed-on: https://go-review.googlesource.com/13270
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-05 23:16:22 +00:00
Russ Cox
0fb87abddf cmd/go: fix handling of vendored imports in foo_test.go files
Fixes #11977.
Fixes #11988.

Change-Id: I9f80006946d3752ee6d644ee51f2decfeaca1ff6
Reviewed-on: https://go-review.googlesource.com/13230
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-08-05 23:13:19 +00:00
Robert Griesemer
98aa82287f spec: clarify semantics of built-in functions 'complex', 'real', and 'imag'
For #11669, #11540, #11945, #11946, #11947.

Change-Id: Ifb0053c498cee9f3473c396f9338d82bd856c110
Reviewed-on: https://go-review.googlesource.com/12860
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-08-05 21:09:49 +00:00
Russ Cox
46a2913882 crypto/tls: fix ConnectionState().VerifiedChains for resumed connection
Strengthening VerifyHostname exposed the fact that for resumed
connections, ConnectionState().VerifiedChains was not being saved
and restored during the ClientSessionCache operations.
Do that.

This change just saves the verified chains in the client's session
cache. It does not re-verify the certificates when resuming a
connection.

There are arguments both ways about this: we want fast, light-weight
resumption connections (thus suggesting that we shouldn't verify) but
it could also be a little surprising that, if the verification config
is changed, that would be ignored if the same session cache is used.

On the server side we do re-verify client-auth certificates, but the
situation is a little different there. The client session cache is an
object in memory that's reset each time the process restarts. But the
server's session cache is a conceptual object, held by the clients, so
can persist across server restarts. Thus the chance of a change in
verification config being surprisingly ignored is much higher in the
server case.

Fixes #12024.

Change-Id: I3081029623322ce3d9f4f3819659fdd9a381db16
Reviewed-on: https://go-review.googlesource.com/13164
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
2015-08-05 19:59:28 +00:00
Russ Cox
0290d51b4a build: clean current tree in clean.bash
Otherwise clean.bash cleans $GOROOT, which might be something else entirely.

Fixes #12003.

Change-Id: I2ad5369017dde6db25f0c0514bc27c33d0a8bf54
Reviewed-on: https://go-review.googlesource.com/13251
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-08-05 19:36:15 +00:00
Jed Denlea
26049f6f91 net/http: close server conn after broken trailers
Prior to this change, broken trailers would be handled by body.Read, and
an error would be returned to its caller (likely a Handler), but that
error would go completely unnoticed by the rest of the server flow
allowing a broken connection to be reused.  This is a possible request
smuggling vector.

Fixes #12027.

Change-Id: I077eb0b8dff35c5d5534ee5f6386127c9954bd58
Reviewed-on: https://go-review.googlesource.com/13148
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-05 19:30:24 +00:00
Adam Langley
f51b7fbdc4 crypto/tls: update testing certificates.
This change alters the certificate used in many tests so that it's no
longer self-signed. This allows some tests to exercise the standard
certificate verification paths in the future.

Change-Id: I9c3fcd6847eed8269ff3b86d9b6966406bf0642d
Reviewed-on: https://go-review.googlesource.com/13244
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
2015-08-05 19:06:51 +00:00
Russ Cox
b7fa8b557d go/build: fix internal/testenv dependency
Change-Id: Id1e30d70d6891ef12110f8e7832b94eeac9e2fa9
Reviewed-on: https://go-review.googlesource.com/13250
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-05 17:32:43 +00:00
Austin Clements
d57f037302 runtime: don't recheck heap trigger for periodic GC
88e945f introduced a non-speculative double check of the heap trigger
before actually starting a concurrent GC. This was necessary to fix a
race for heap-triggered GC, but broke sysmon-triggered periodic GC,
since the heap check will of course fail for periodically triggered
GC.

Fix this by telling startGC whether or not this GC was triggered by
heap size or a timer and only doing the heap size double check for GCs
triggered by heap size.

Fixes #12026.

Change-Id: I7c3f6ec364545c36d619f2b4b3bf3b758e3bcbd6
Reviewed-on: https://go-review.googlesource.com/13168
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-05 17:28:56 +00:00
Robert Griesemer
3dd3ab41ac spec: better organization of arithmetic operator section
First step towards cleaning up the operator section - no language
changes. Specifically:

- Grouped arithmetic operations by types (integer, floating-point,
  string), with corresponding h4 headings.

- Changed Operator precedence title from h3 to h4.

- Moved Integer Overflow section after integer operations and changed
  its title from h3 to h4.

This puts things that belong together closer. No heading id's were
lost (in case of references from outside the spec).

Change-Id: I6b349ba8d86a6ae29b596beb297cc45c81e69399
Reviewed-on: https://go-review.googlesource.com/13143
Reviewed-by: Rob Pike <r@golang.org>
2015-08-05 17:05:07 +00:00
Robert Griesemer
05614bfcfa spec: fix inconsistency of visibility rules for method names
Inconsistency identified by Anmol Sethi (anmol@aubble.com).

Fixes #10341.

Change-Id: I1a1f5b22aad29b56280f81026feaa37a61b3e0a9
Reviewed-on: https://go-review.googlesource.com/13132
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-05 17:03:36 +00:00
Robert Griesemer
85789daac3 spec: clarify that short variable declarations can redeclare parameters
Fixes #9837.

Change-Id: Ia513c7e5db221eee8e3ab0affa6d3688d2099fd9
Reviewed-on: https://go-review.googlesource.com/13130
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-05 17:01:05 +00:00
Robert Griesemer
87c8707e6f spec: clarify sentence about non-constant shifts
Fixes #10514.

Change-Id: Iae95a304d3ebb1ed82567aa234e05dc434db984f
Reviewed-on: https://go-review.googlesource.com/13098
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-05 17:00:11 +00:00
Russ Cox
1579822be1 doc/go1.5: fix hyperlink for runtime/trace
Missed in CL 13074.

Change-Id: Ic0600341abbc423cd8d7b2201bf50e3b0bf398a7
Reviewed-on: https://go-review.googlesource.com/13167
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-05 16:14:45 +00:00
Russ Cox
47e0e4233f go/build: enable cgo on freebsd/arm
Now that it works we need to turn it back on.

Fixes #10119.

Change-Id: I9c62d3026f7bb62c49a601ad73f33bf655372915
Reviewed-on: https://go-review.googlesource.com/13162
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-05 16:14:05 +00:00
Russ Cox
7d9faaa19f cmd/go: skip external tests on freebsd-arm builder
It is just far too slow.
I have a CL for Go 1.6 that makes many of these into internal tests.
That will improve the coverage.

It does not matter much, because basically none of the go command
tests are architecture dependent, so the other builders will catch
any problems.

Fixes freebsd-arm builder.

Change-Id: I8b2f6ac2cc1e7657019f7731c6662dc43e20bfb5
Reviewed-on: https://go-review.googlesource.com/13166
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-05 16:13:37 +00:00
Russ Cox
7721ac0535 internal/testenv: add Builder, to report builder name
This works after golang.org/cl/13120 is running on the
coordinator (maybe it already is).

Change-Id: I4053d8e2f32fafd47b927203a6f66d5858e23376
Reviewed-on: https://go-review.googlesource.com/13165
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-05 16:13:25 +00:00
Austin Clements
43a404cf5f doc: mention new DWARF line table decoder in go1.5.html
Change-Id: I4e8c20284255e0e17b6fb72475d2d37f49994788
Reviewed-on: https://go-review.googlesource.com/13113
Reviewed-by: Rob Pike <r@golang.org>
2015-08-05 14:59:24 +00:00
Dmitry Vyukov
de641ef0c4 doc/go1.5.html: update references to runtime/trace package
Tracing functionality was moved from runtime/pprof to runtime/trace.

Change-Id: I694e0f209d043c7ffecb113f1825175bf963dde3
Reviewed-on: https://go-review.googlesource.com/13074
Reviewed-by: Rob Pike <r@golang.org>
2015-08-05 08:13:15 +00:00
Russ Cox
2a60d77059 runtime: align stack pointer during initcgo call on arm
This is what is causing freebsd/arm to crash mysteriously when using cgo.
The bug was introduced in golang.org/cl/4030, which moved this code out
of rt0_go and into its own function. The ARM ABI says that calls must
be made with the stack pointer at an 8-byte boundary, but only FreeBSD
seems to crash when this is violated.

Fixes #10119.

Change-Id: Ibdbe76b2c7b80943ab66b8abbb38b47acb70b1e5
Reviewed-on: https://go-review.googlesource.com/13161
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
2015-08-05 05:31:34 +00:00
Andrew Gerrand
31b0b73924 doc: adjust installation instructions dynamically for a given download
This change allows the download page to redirect the user to
/doc/install?download=filename so the user can see installation
instructions specific to the file they are downloading.

This change also expands the "Test your Go installation" section
to instruct the user to create a workspace, hopefully leading
to less confusion down the line.

It also changes the front page download link to go directly
to the downloads page, which will in turn take them to the
installation instructions (the original destination).

This is related to this change to the tools repo:
https://golang.org/cl/13180

Change-Id: I658327bdb93ad228fb1846e389b281b15da91b1d
Reviewed-on: https://go-review.googlesource.com/13151
Reviewed-by: Chris Broadfoot <cbro@golang.org>
2015-08-05 04:18:56 +00:00
Josh Bleecher Snyder
f91ff1a509 [dev.ssa] cmd/compile: add SSA pass to move values closer to uses
Even this very simple, restricted initial implementation helps.

While running make.bash, it moves 84437 values
to new, closer homes.

As a concrete example:

func f_ssa(i, j int, b bool) int {
	if !b {
		return 0
	}
	return i + j
}

It cuts off one stack slot and two instructions:

Before:

"".f_ssa t=1 size=96 value=0 args=0x20 locals=0x18
	0x0000 00000 (x.go:3)	TEXT	"".f_ssa(SB), $24-32
	0x0000 00000 (x.go:3)	SUBQ	$24, SP
	0x0004 00004 (x.go:3)	FUNCDATA	$0, "".gcargs·0(SB)
	0x0004 00004 (x.go:3)	FUNCDATA	$1, "".gclocals·1(SB)
	0x0004 00004 (x.go:5)	MOVQ	$0, AX
	0x0006 00006 (x.go:3)	MOVQ	32(SP), CX
	0x000b 00011 (x.go:3)	MOVQ	40(SP), DX
	0x0010 00016 (x.go:3)	LEAQ	48(SP), BX
	0x0015 00021 (x.go:3)	MOVB	(BX), BPB
	0x0018 00024 (x.go:3)	MOVQ	$0, SI
	0x001a 00026 (x.go:3)	MOVQ	SI, 56(SP)
	0x001f 00031 (x.go:3)	TESTB	BPB, BPB
	0x0022 00034 (x.go:5)	MOVQ	AX, (SP)
	0x0026 00038 (x.go:3)	MOVQ	CX, 8(SP)
	0x002b 00043 (x.go:3)	MOVQ	DX, 16(SP)
	0x0030 00048 (x.go:4)	JEQ	74
	0x0032 00050 (x.go:3)	MOVQ	8(SP), AX
	0x0037 00055 (x.go:3)	MOVQ	16(SP), CX
	0x003c 00060 (x.go:7)	LEAQ	(AX)(CX*1), DX
	0x0040 00064 (x.go:7)	MOVQ	DX, 56(SP)
	0x0045 00069 (x.go:3)	ADDQ	$24, SP
	0x0049 00073 (x.go:3)	RET
	0x004a 00074 (x.go:5)	MOVQ	(SP), AX
	0x004e 00078 (x.go:5)	MOVQ	AX, 56(SP)
	0x0053 00083 (x.go:3)	JMP	69

After:

"".f_ssa t=1 size=80 value=0 args=0x20 locals=0x10
	0x0000 00000 (x.go:3)	TEXT	"".f_ssa(SB), $16-32
	0x0000 00000 (x.go:3)	SUBQ	$16, SP
	0x0004 00004 (x.go:3)	FUNCDATA	$0, "".gcargs·0(SB)
	0x0004 00004 (x.go:3)	FUNCDATA	$1, "".gclocals·1(SB)
	0x0004 00004 (x.go:3)	MOVQ	32(SP), AX
	0x0009 00009 (x.go:3)	MOVQ	24(SP), CX
	0x000e 00014 (x.go:3)	LEAQ	40(SP), DX
	0x0013 00019 (x.go:3)	MOVB	(DX), BL
	0x0015 00021 (x.go:3)	MOVQ	$0, BP
	0x0017 00023 (x.go:3)	MOVQ	BP, 48(SP)
	0x001c 00028 (x.go:3)	TESTB	BL, BL
	0x001e 00030 (x.go:3)	MOVQ	AX, (SP)
	0x0022 00034 (x.go:3)	MOVQ	CX, 8(SP)
	0x0027 00039 (x.go:4)	JEQ	64
	0x0029 00041 (x.go:3)	MOVQ	8(SP), AX
	0x002e 00046 (x.go:3)	MOVQ	(SP), CX
	0x0032 00050 (x.go:7)	LEAQ	(AX)(CX*1), DX
	0x0036 00054 (x.go:7)	MOVQ	DX, 48(SP)
	0x003b 00059 (x.go:3)	ADDQ	$16, SP
	0x003f 00063 (x.go:3)	RET
	0x0040 00064 (x.go:5)	MOVQ	$0, AX
	0x0042 00066 (x.go:5)	MOVQ	AX, 48(SP)
	0x0047 00071 (x.go:3)	JMP	59

Of course, the old backend is still well ahead:

"".f_ssa t=1 size=48 value=0 args=0x20 locals=0x0
	0x0000 00000 (x.go:3)	TEXT	"".f_ssa(SB), $0-32
	0x0000 00000 (x.go:3)	NOP
	0x0000 00000 (x.go:3)	NOP
	0x0000 00000 (x.go:3)	FUNCDATA	$0, gclocals·a8eabfc4a4514ed6b3b0c61e9680e440(SB)
	0x0000 00000 (x.go:3)	FUNCDATA	$1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
	0x0000 00000 (x.go:4)	CMPB	"".b+24(FP), $0
	0x0005 00005 (x.go:4)	JNE	17
	0x0007 00007 (x.go:5)	MOVQ	$0, "".~r3+32(FP)
	0x0010 00016 (x.go:5)	RET
	0x0011 00017 (x.go:7)	MOVQ	"".i+8(FP), BX
	0x0016 00022 (x.go:7)	MOVQ	"".j+16(FP), BP
	0x001b 00027 (x.go:7)	ADDQ	BP, BX
	0x001e 00030 (x.go:7)	MOVQ	BX, "".~r3+32(FP)
	0x0023 00035 (x.go:7)	RET

Some regalloc improvements should help considerably.

Change-Id: I95bb5dd83e56afd70ae4e983f1d32dffd0c3d46a
Reviewed-on: https://go-review.googlesource.com/13142
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-05 02:37:24 +00:00
Andrew Gerrand
e019767ecb doc: bump minimum requirement to OS X 10.7
Fixes #11995

Change-Id: I9e2901d77ebde705f59822e7d4a8163cbacffcd7
Reviewed-on: https://go-review.googlesource.com/13150
Reviewed-by: Rob Pike <r@golang.org>
2015-08-05 00:52:00 +00:00
Keith Randall
d1c15a0e3e [dev.ssa] cmd/compile/internal/ssa: implement ITAB
Implement ITAB, selecting the itable field of an interface.

Soften the lowering check to allow lowerings that leave
generic but dead ops behind.  (The ITAB lowering does this.)

Change-Id: Icc84961dd4060d143602f001311aa1d8be0d7fc0
Reviewed-on: https://go-review.googlesource.com/13144
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2015-08-04 23:32:42 +00:00
Josh Bleecher Snyder
9495e45c80 [dev.ssa] cmd/compile: make GOSSAFUNC trigger logging
I find myself always adding this in temporarily.
Make it permanent.

Change-Id: I1646b3930a07d0ea01840736ccd449b7fd24f06e
Reviewed-on: https://go-review.googlesource.com/13141
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-04 22:53:11 +00:00
Josh Bleecher Snyder
573c791e81 [dev.ssa] cmd/compile: treat control ops as live at end of block
Failure to treat control ops as live can lead
to them being eliminated when they live in
other blocks.

Change-Id: I604a1977a3d3884b1f4516bea4e15885ce38272d
Reviewed-on: https://go-review.googlesource.com/13138
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-04 22:48:34 +00:00
Josh Bleecher Snyder
54dca047dd [dev.ssa] cmd/compile: always print block control values
They were being omitted after scheduling.

Change-Id: Ia20e2dcb61fde9ec854918b958c3897bafd282a6
Reviewed-on: https://go-review.googlesource.com/13140
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-04 22:05:56 +00:00
Robert Griesemer
3cfc34a555 reflect: fix doc string
Fixes #12017.

Change-Id: I3dfcf9d0b62cae02eca1973383f0aad286a6ef4d
Reviewed-on: https://go-review.googlesource.com/13136
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-04 21:10:58 +00:00
Keith Randall
683f5d7bdb [dev.ssa] cmd/compile/internal/ssa: put new values for block rewrites in rewritten block
Don't put them in the control value's block.
That may be many blocks up the dominator tree.

Change-Id: Iab3ea36a890ffe0e355dadec7aeb676901c4f070
Reviewed-on: https://go-review.googlesource.com/13134
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2015-08-04 19:38:24 +00:00
Josh Bleecher Snyder
b8efee0d8a [dev.ssa] cmd/compile: log progs during ssa codegen
This is helpful when debugging generated code.

Change-Id: I268efa3593a03bb2c4e9f07d9034c004cd40df41
Reviewed-on: https://go-review.googlesource.com/13099
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-04 19:37:19 +00:00
Austin Clements
be39a42920 runtime: fix typos in comments
Change-Id: I66f7937b22bb6e05c3f2f0f2a057151020ad9699
Reviewed-on: https://go-review.googlesource.com/13049
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 18:54:56 +00:00
Austin Clements
e3870aa6f3 runtime: fix assist utilization computation
When commit 510fd13 enabled assists during the scan phase, it failed
to also update the code in the GC controller that computed the assist
CPU utilization and adjusted the trigger based on it. Fix that code so
it uses the start of the scan phase as the wall-clock time when
assists were enabled rather than the start of the mark phase.

Change-Id: I05013734b4448c3e2c730dc7b0b5ee28c86ed8cf
Reviewed-on: https://go-review.googlesource.com/13048
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 18:54:53 +00:00
Austin Clements
1fb01a88f9 runtime: revise assist ratio aggressively
At the start of a GC cycle, the garbage collector computes the assist
ratio based on the total scannable heap size. This was intended to be
conservative; after all, this assumes the entire heap may be reachable
and hence needs to be scanned. But it only assumes that the *current*
entire heap may be reachable. It fails to account for heap allocated
during the GC cycle. If the trigger ratio is very low (near zero), and
most of the heap is reachable when GC starts (which is likely if the
trigger ratio is near zero), then it's possible for the mutator to
create new, reachable heap fast enough that the assists won't keep up
based on the assist ratio computed at the beginning of the cycle. As a
result, the heap can grow beyond the heap goal (by hundreds of megs in
stress tests like in issue #11911).

We already have some vestigial logic for dealing with situations like
this; it just doesn't run often enough. Currently, every 10 ms during
the GC cycle, the GC revises the assist ratio. This was put in before
we switched to a conservative assist ratio (when we really were using
estimates of scannable heap), and it turns out to be exactly what we
need now. However, every 10 ms is far too infrequent for a rapidly
allocating mutator.

This commit reuses this logic, but replaces the 10 ms timer with
revising the assist ratio every time the heap is locked, which
coincides precisely with when the statistics used to compute the
assist ratio are updated.

Fixes #11911.

Change-Id: I377b231ab064946228378fa10422a46d1b50f4c5
Reviewed-on: https://go-review.googlesource.com/13047
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 18:54:48 +00:00
Austin Clements
f9dc3382ad runtime: when gcpacertrace > 0, print information about assist ratio
This was useful in debugging the mutator assist behavior for #11911,
and it fits with the other gcpacertrace output.

Change-Id: I1e25590bb4098223a160de796578bd11086309c7
Reviewed-on: https://go-review.googlesource.com/13046
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 18:54:46 +00:00
Austin Clements
fc9ca85f4c runtime: make sweep proportional to spans bytes allocated
Proportional concurrent sweep is currently based on a ratio of spans
to be swept per bytes of object allocation. However, proportional
sweeping is performed during span allocation, not object allocation,
in order to minimize contention and overhead. Since objects are
allocated from spans after those spans are allocated, the system tends
to operate in debt, which means when the next GC cycle starts, there
is often sweep debt remaining, so GC has to finish the sweep, which
delays the start of the cycle and delays enabling mutator assists.

For example, it's quite likely that many Ps will simultaneously refill
their span caches immediately after a GC cycle (because GC flushes the
span caches), but at this point, there has been very little object
allocation since the end of GC, so very little sweeping is done. The
Ps then allocate objects from these cached spans, which drives up the
bytes of object allocation, but since these allocations are coming
from cached spans, nothing considers whether more sweeping has to
happen. If the sweep ratio is high enough (which can happen if the
next GC trigger is very close to the retained heap size), this can
easily represent a sweep debt of thousands of pages.

Fix this by making proportional sweep proportional to the number of
bytes of spans allocated, rather than the number of bytes of objects
allocated. Prior to allocating a span, both the small object path and
the large object path ensure credit for allocating that span, so the
system operates in the black, rather than in the red.

Combined with the previous commit, this should eliminate all sweeping
from GC start up. On the stress test in issue #11911, this reduces the
time spent sweeping during GC (and delaying start up) by several
orders of magnitude:

                mean    99%ile     max
    pre fix      1 ms    11 ms   144 ms
    post fix   270 ns   735 ns   916 ns

Updates #11911.

Change-Id: I89223712883954c9d6ec2a7a51ecb97172097df3
Reviewed-on: https://go-review.googlesource.com/13044
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 18:54:44 +00:00
Austin Clements
e30c6d64ba runtime: always give concurrent sweep some heap distance
Currently it's possible for the next_gc heap size trigger computed for
the next GC cycle to be less than the current allocated heap size.
This means the next cycle will start immediately, which means there's
no time to perform the concurrent sweep between GC cycles. This places
responsibility for finishing the sweep on GC itself, which delays GC
start-up and hence delays mutator assist.

Fix this by ensuring that next_gc is always at least a little higher
than the allocated heap size, so we won't trigger the next cycle
instantly.

Updates #11911.

Change-Id: I74f0b887bf187518d5fedffc7989817cbcf30592
Reviewed-on: https://go-review.googlesource.com/13043
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 18:54:41 +00:00
Austin Clements
fb5230af8a runtime: assist the GC during GC startup and shutdown
Currently there are two sensitive periods during which a mutator can
allocate past the heap goal but mutator assists can't be enabled: 1)
at the beginning of GC between when the heap first passes the heap
trigger and sweep termination and 2) at the end of GC between mark
termination and when the background GC goroutine parks. During these
periods there's no back-pressure or safety net, so a rapidly
allocating mutator can allocate past the heap goal. This is
exacerbated if there are many goroutines because the GC coordinator is
scheduled as any other goroutine, so if it gets preempted during one
of these periods, it may stay preempted for a long period (10s or 100s
of milliseconds).

Normally the mutator does scan work to create back-pressure against
allocation, but there is no scan work during these periods. Hence, as
a fall back, if a mutator would assist but can't yet, simply yield the
CPU. This delays the mutator somewhat, but more importantly gives more
CPU time to the GC coordinator for it to complete the transition.

This is obviously a workaround. Issue #11970 suggests a far better but
far more invasive way to fix this.

Updates #11911. (This very nearly fixes the issue, but about once
every 15 minutes I get a GC cycle where the assists are enabled but
don't do enough work.)

Change-Id: I9768b79e3778abd3e06d306596c3bd77f65bf3f1
Reviewed-on: https://go-review.googlesource.com/13026
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2015-08-04 18:54:38 +00:00
Austin Clements
88e945fd23 runtime: recheck GC trigger before actually starting GC
Currently allocation checks the GC trigger speculatively during
allocation and then triggers the GC without rechecking. As a result,
it's possible for G 1 and G 2 to detect the trigger simultaneously,
both enter startGC, G 1 actually starts GC while G 2 gets preempted
until after the whole GC cycle, then G 2 immediately starts another GC
cycle even though the heap is now well under the trigger.

Fix this by re-checking the GC trigger non-speculatively just before
actually kicking off a new GC cycle.

This contributes to #11911 because when this happens, we definitely
don't finish the background sweep before starting the next GC cycle,
which can significantly delay the start of concurrent scan.

Change-Id: I560ab79ba5684ba435084410a9765d28f5745976
Reviewed-on: https://go-review.googlesource.com/13025
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
2015-08-04 18:54:32 +00:00
Ian Lance Taylor
d5f5e658ae doc: link to design doc for GOMAXPROCS change in go1.5.html
Change-Id: Ifac10621fece766f3a0e8551e98d1f8d7072852f
Reviewed-on: https://go-review.googlesource.com/13068
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
2015-08-04 18:31:56 +00:00
Ian Lance Taylor
c2ef8e752f cmd/go: fix documentation for exported functions
I accidentally submitted https://golang.org/cl/13080 too early.

Update #11955.

Change-Id: I1a5a6860bb46bc4bc6fd278f8a867d2dd9e411e1
Reviewed-on: https://go-review.googlesource.com/13096
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-04 18:30:00 +00:00
Vincent Batts
a1d093d95d archive/tar: don't treat multiple file system links as a tar hardlink
Do not assume that if stat shows multiple links that we should mark the
file as a hardlink in the tar format.  If the hardlink link was not
referenced, this caused a link to "/".  On an overlay file system, all
files have multiple links.

The caller must keep the inode references and set TypeLink, Size = 0,
and LinkName themselves.

Change-Id: I873b8a235bc8f8fbb271db74ee54232da36ca013
Reviewed-on: https://go-review.googlesource.com/13045
Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-08-04 17:34:43 +00:00
Ian Lance Taylor
bc5a6ce6be cmd/go: document that functions are exported by cgo
The buildmode docs mention exported functions, but don't say anything
about how to export them.  Mention the cgo tool to make this somewhat
clearer.

Fixes #11955.

Change-Id: Ie5420445daa87f5aceec6ad743465d5d32d0a786
Reviewed-on: https://go-review.googlesource.com/13080
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 04:50:07 +00:00
Todd Neal
38ed6c10eb [dev.ssa] cmd/compile: simplify repeated OCOM
Rewrite ^{n}x to be ^{n % 2}x.  This will eventually resolve a fuzz
issue that breaks v1.5.

Updates #11352

Change-Id: I1b3f93872d06222f9ff5f6fd5580178ebaf4c003
Reviewed-on: https://go-review.googlesource.com/13110
Reviewed-by: Keith Randall <khr@golang.org>
2015-08-04 02:18:56 +00:00
Rob Pike
ecead89be9 go/types: remove the renaming import of go/constant
For niceness, when go/exact was moved from x/tools, it
was renamed go/constant.

For simplicity, when go/types was moved from x/tools, its
imports of (now) go/constant were done with a rename:

    import exact "go/constant"

This kept the code just as it was before and avoided the issue
of what to call the internal constant called, um, constant.

But not all was hidden, as the text of some fields of structs and
the like leaked the old name, so things like "exact.Value" appeared
in type definitions and function signatures in the documentation.
This is unacceptable.

Fix the documentation issue by fixing the code. Rename the constant
constant constant_, and remove the renaming import.

This should go into 1.5. It's mostly a mechanical change, is
internal to the package, and fixes the documentation. It contains
no semantic changes except to fix a benchmark that was broken
in the original transition.

Fixes #11949.

Change-Id: Ieb94b6558535b504180b1378f19e8f5a96f92d3c
Reviewed-on: https://go-review.googlesource.com/13051
Reviewed-by: Russ Cox <rsc@golang.org>
2015-08-04 01:56:58 +00:00
Caleb Spare
2bd5237070 doc: link to the release cycle from contribute.html
Change-Id: Ia5d41b66006682084fcbfac3da020946ea3dd116
Reviewed-on: https://go-review.googlesource.com/13093
Reviewed-by: Andrew Gerrand <adg@golang.org>
2015-08-04 01:40:22 +00:00