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2016-04-06runtime: rename os1_linux.go to os_linux.goBrad Fitzpatrick
Change-Id: I938f61763c3256a876d62aeb54ef8c25cc4fc90e Reviewed-on: https://go-review.googlesource.com/21567 Reviewed-by: Minux Ma <minux@golang.org>
2016-04-06runtime: merge os_linux.go into os1_linux.goBrad Fitzpatrick
Change-Id: I791c47014fe69e8529c7b2f0b9a554e47902d46c Reviewed-on: https://go-review.googlesource.com/21566 Reviewed-by: Minux Ma <minux@golang.org>
2016-04-01runtime: support symbolic backtrace of C code in a cgo crashIan Lance Taylor
The new function runtime.SetCgoTraceback may be used to register stack traceback and symbolizer functions, written in C, to do a stack traceback from cgo code. There is a sample implementation of runtime.SetCgoSymbolizer at github.com/ianlancetaylor/cgosymbolizer. Just importing that package is sufficient to get symbolic C backtraces. Currently only supported on linux/amd64. Change-Id: If96ee2eb41c6c7379d407b9561b87557bfe47341 Reviewed-on: https://go-review.googlesource.com/17761 Reviewed-by: Austin Clements <austin@google.com>
2016-03-02all: single space after period.Brad Fitzpatrick
The tree's pretty inconsistent about single space vs double space after a period in documentation. Make it consistently a single space, per earlier decisions. This means contributors won't be confused by misleading precedence. This CL doesn't use go/doc to parse. It only addresses // comments. It was generated with: $ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])') $ go test go/doc -update Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7 Reviewed-on: https://go-review.googlesource.com/20022 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Dave Day <djd@golang.org> Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-02-21all: use cannot instead of can notJosh Bleecher Snyder
You can not use cannot, but you cannot spell cannot can not. Change-Id: I2f0971481a460804de96fd8c9e46a9cc62a3fc5b Reviewed-on: https://go-review.googlesource.com/19772 Reviewed-by: Rob Pike <r@golang.org>
2016-01-14runtime: minimize time between lockextra/unlockextraIan Lance Taylor
This doesn't fix a bug, but may improve performance in programs that have many concurrent calls from C to Go. The old code made several system calls between lockextra and unlockextra. That could be happening while another thread is spinning acquiring lockextra. This changes the code to not make any system calls while holding the lock. Change-Id: I50576478e478670c3d6429ad4e1b7d80f98a19d8 Reviewed-on: https://go-review.googlesource.com/18548 Reviewed-by: Russ Cox <rsc@golang.org>
2016-01-09runtime: for c-archive/c-shared, install signal handlers synchronouslyIan Lance Taylor
The previous behaviour of installing the signal handlers in a separate thread meant that Go initialization raced with non-Go initialization if the non-Go initialization also wanted to install signal handlers. Make installing signal handlers synchronous so that the process-wide behavior is predictable. Update #9896. Change-Id: Ice24299877ec46f8518b072a381932d273096a32 Reviewed-on: https://go-review.googlesource.com/18150 Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-01-06runtime: preserve signal stack when calling Go on C threadIan Lance Taylor
When calling a Go function on a C thread, if the C thread already has an alternate signal stack, use that signal stack instead of installing a new one. Update #9896. Change-Id: I62aa3a6a4a1dc4040fca050757299c8e6736987c Reviewed-on: https://go-review.googlesource.com/18108 Reviewed-by: Russ Cox <rsc@golang.org>
2015-11-24runtime: use a proper type, sigset, for m.sigmaskElias Naur
Replace the cross platform but unsafe [4]uintptr type with a OS specific type, sigset. Most OSes already define sigset, and this change defines a suitable sigset for the OSes that don't (darwin, openbsd). The OSes that don't use m.sigmask (windows, plan9, nacl) now defines sigset as the empty type, struct{}. The gain is strongly typed access to m.sigmask, saving a dynamic size sanity check and unsafe.Pointer casting. Also, some storage is saved for each M, since [4]uinptr was conservative for most OSes. The cost is that OSes that don't need m.sigmask has to define sigset. completes ./all.bash with GOOS linux, on amd64 completes ./make.bash with GOOSes openbsd, android, plan9, windows, darwin, solaris, netbsd, freebsd, dragonfly, all amd64. With GOOS=nacl ./make.bash failed with a seemingly unrelated error. [Replay of CL 16942 by Elias Naur.] Change-Id: I98f144d626033ae5318576115ed635415ac71b2c Reviewed-on: https://go-review.googlesource.com/17033 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Russ Cox <rsc@golang.org>
2015-11-18runtime: fix bad signal stack when using cgo-created threads and async signalsRuss Cox
Cgo-created threads transition between having associated Go g's and m's and not. A signal arriving during the transition could think it was safe and appropriate to run Go signal handlers when it was in fact not. Avoid the race by masking all signals during the transition. Fixes #12277. Change-Id: Ie9711bc1d098391d58362492197a7e0f5b497d14 Reviewed-on: https://go-review.googlesource.com/16915 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Russ Cox <rsc@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-11-18Revert "runtime: use a proper type, sigset, for m.sigmask"Russ Cox
This reverts commit 7db77271e423604c3b58b4c4da60ddc3c3eecc0d. Change-Id: I6d8855eb05ca331025dc49a5533c6da4d1fa4e84 Reviewed-on: https://go-review.googlesource.com/17030 Reviewed-by: Russ Cox <rsc@golang.org>
2015-11-17runtime: use a proper type, sigset, for m.sigmaskElias Naur
Replace the cross platform but unsafe [4]uintptr type with a OS specific type, sigset. Most OSes already define sigset, and this change defines a suitable sigset for the OSes that don't (darwin, openbsd). The OSes that don't use m.sigmask (windows, plan9, nacl) now defines sigset as the empty type, struct{}. The gain is strongly typed access to m.sigmask, saving a dynamic size sanity check and unsafe.Pointer casting. Also, some storage is saved for each M, since [4]uinptr was conservative for most OSes. The cost is that OSes that don't need m.sigmask has to define sigset. completes ./all.bash with GOOS linux, on amd64 completes ./make.bash with GOOSes openbsd, android, plan9, windows, darwin, solaris, netbsd, freebsd, dragonfly, all amd64. With GOOS=nacl ./make.bash failed with a seemingly unrelated error. R=go1.7 Change-Id: Ib460379f063eb83d393e1c5efe7333a643c1595e Reviewed-on: https://go-review.googlesource.com/16942 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org>
2015-11-12runtime: update newosproc asm to access m.id directlyMatthew Dempsky
darwin/386, freebsd/386, and linux/386 use a setldt system call to setup each M's thread-local storage area, and they need access to the M's id for this. The current code copies m.id into m.tls[0] (and this logic has been cargo culted to OSes like NetBSD and OpenBSD, which don't even need m.id to configure TLS), and then the 386 assembly loads m.tls[0]... but since the assembly code already has a pointer to the M, it might as well just load m.id directly. Change-Id: I1a7278f1ec8ebda8d1de3aa3a61993070e3a8cdf Reviewed-on: https://go-review.googlesource.com/16881 Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-11-12runtime: ignore rt_sigaction error if it is for SIGRTMAXMichael Hudson-Doyle
A forward port of https://codereview.appspot.com/124900043/ which somehow got lost somewhere. Fixes #13024 Change-Id: Iab128899e65c51d90f6704e3e1b2fc9326e3a1c2 Reviewed-on: https://go-review.googlesource.com/16853 Reviewed-by: Russ Cox <rsc@golang.org>
2015-11-12runtime: break out system-specific constants into package sysMichael Matloob
runtime/internal/sys will hold system-, architecture- and config- specific constants. Updates #11647 Change-Id: I6db29c312556087a42e8d2bdd9af40d157c56b54 Reviewed-on: https://go-review.googlesource.com/16817 Reviewed-by: Russ Cox <rsc@golang.org>
2015-11-12runtime: restructured os1_linux.go, added mips64 supportYao Zhang
Linux/mips64 uses a different type of sigset. To deal with it, related functions in os1_linux.go is refactored to os1_linux_generic.go (used for non-mips64 architectures), and os1_linux_mips64x.go (only used in mips64{,le}), to avoid code copying. Change-Id: I5cadfccd86bfc4b30bf97e12607c3c614903ea4c Reviewed-on: https://go-review.googlesource.com/14991 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-10-26runtime: use a 64kb system stack on armDavid Crawshaw
I went looking for an arm system whose stacks are by default smaller than 64KB. In fact the smallest common linux target I could find was Android, which like iOS uses 1MB stacks. Fixes #11873 Change-Id: Ieeb66ad095b3da18d47ba21360ea75152a4107c6 Reviewed-on: https://go-review.googlesource.com/14602 Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com> Reviewed-by: Minux Ma <minux@golang.org>
2015-07-27runtime: pass a smaller buffer to sched_getaffinity on ARMMichael Hudson-Doyle
The system stack is only around 8kb on ARM so one can't put an 8kb buffer on the stack. More than 1024 ARM cores seems sufficiently unlikely for the foreseeable future. Fixes #11853 Change-Id: I7cb27c1250a6153f86e269c172054e9dfc218c72 Reviewed-on: https://go-review.googlesource.com/12622 Reviewed-by: Austin Clements <austin@google.com>
2015-07-22runtime: handle linux CPU masks up to 64k CPUsRuss Cox
Fixes #11823. Change-Id: Ic949ccb9657478f8ca34fdf1a6fe88f57db69f24 Reviewed-on: https://go-review.googlesource.com/12535 Reviewed-by: Austin Clements <austin@google.com>
2015-07-22runtime: if we don't handle a signal on a non-Go thread, raise itIan Lance Taylor
In the past badsignal would crash the program. In https://golang.org/cl/10757044 badsignal was changed to call sigsend, to fix issue #3250. The effect of this was that when a non-Go thread received a signal, and os/signal.Notify was not being used to check for occurrences of the signal, the signal was ignored. This changes the code so that if os/signal.Notify is not being used, then the signal handler is reset to what it was, and the signal is raised again. This lets non-Go threads handle the signal as they wish. In particular, it means that a segmentation violation in a non-Go thread will ordinarily crash the process, as it should. Fixes #10139. Update #11794. Change-Id: I2109444aaada9d963ad03b1d071ec667760515e5 Reviewed-on: https://go-review.googlesource.com/12503 Reviewed-by: Russ Cox <rsc@golang.org> Run-TryBot: Ian Lance Taylor <iant@golang.org>
2015-06-24runtime: set m.procid always on LinuxRuss Cox
For debuggers and other program inspectors. Fixes #9914. Change-Id: I670728cea28c045e6eaba1808c550ee2f34d16ff Reviewed-on: https://go-review.googlesource.com/11341 Reviewed-by: Austin Clements <austin@google.com>
2015-06-02runtime: clean up signalstack APIAustin Clements
Currently signalstack takes a lower limit and a length and all calls hard-code the passed length. Change the API to take a *stack and compute the lower limit and length from the passed stack. This will make it easier for the runtime to steal some space from the top of the stack since it eliminates the hard-coded stack sizes. Change-Id: I7d2a9f45894b221f4e521628c2165530bbc57d53 Reviewed-on: https://go-review.googlesource.com/10311 Reviewed-by: Rick Hudson <rlh@golang.org> Reviewed-by: Russ Cox <rsc@golang.org>
2015-05-22runtime: don't always unblock all signalsElias Naur
Ian proposed an improved way of handling signals masks in Go, motivated by a problem where the Android java runtime expects certain signals to be blocked for all JVM threads. Discussion here https://groups.google.com/forum/#!topic/golang-dev/_TSCkQHJt6g Ian's text is used in the following: A Go program always needs to have the synchronous signals enabled. These are the signals for which _SigPanic is set in sigtable, namely SIGSEGV, SIGBUS, SIGFPE. A Go program that uses the os/signal package, and calls signal.Notify, needs to have at least one thread which is not blocking that signal, but it doesn't matter much which one. Unix programs do not change signal mask across execve. They inherit signal masks across fork. The shell uses this fact to some extent; for example, the job control signals (SIGTTIN, SIGTTOU, SIGTSTP) are blocked for commands run due to backquote quoting or $(). Our current position on signal masks was not thought out. We wandered into step by step, e.g., http://golang.org/cl/7323067 . This CL does the following: Introduce a new platform hook, msigsave, that saves the signal mask of the current thread to m.sigsave. Call msigsave from needm and newm. In minit grab set up the signal mask from m.sigsave and unblock the essential synchronous signals, and SIGILL, SIGTRAP, SIGPROF, SIGSTKFLT (for systems that have it). In unminit, restore the signal mask from m.sigsave. The first time that os/signal.Notify is called, start a new thread whose only purpose is to update its signal mask to make sure signals for signal.Notify are unblocked on at least one thread. The effect on Go programs will be that if they are invoked with some non-synchronous signals blocked, those signals will normally be ignored. Previously, those signals would mostly be ignored. A change in behaviour will occur for programs started with any of these signals blocked, if they receive the signal: SIGHUP, SIGINT, SIGQUIT, SIGABRT, SIGTERM. Previously those signals would always cause a crash (unless using the os/signal package); with this change, they will be ignored if the program is started with the signal blocked (and does not use the os/signal package). ./all.bash completes successfully on linux/amd64. OpenBSD is missing the implementation. Change-Id: I188098ba7eb85eae4c14861269cc466f2aa40e8c Reviewed-on: https://go-review.googlesource.com/10173 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-04-24runtime: implement xadduintptr and update system mstats using itSrdjan Petrovic
The motivation is that sysAlloc/Free() currently aren't safe to be called without a valid G, because arm's xadd64() uses locks that require a valid G. The solution here was proposed by Dmitry Vyukov: use xadduintptr() instead of xadd64(), until arm can support xadd64 on all of its architectures (not a trivial task for arm). Change-Id: I250252079357ea2e4360e1235958b1c22051498f Reviewed-on: https://go-review.googlesource.com/9002 Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
2015-04-22runtime: merge clone0 and cloneSrdjan Petrovic
We initially added clone0 to handle the case when G or M don't exist, but it turns out that we could have just modified clone. (It also helps that the function we're invoking in clone0 no longer needs arguments.) As a side-effect, newosproc0 is now supported on all linux archs. Change-Id: Ie603af75d8f164310fc16446052d83743961f3ca Reviewed-on: https://go-review.googlesource.com/9164 Reviewed-by: David Crawshaw <crawshaw@golang.org>
2015-04-14runtime: rename close to closefdDavid Crawshaw
Avoids shadowing the builtin channel close function. Change-Id: I7a729b0937c8248fe27222be61318a88db995eee Reviewed-on: https://go-review.googlesource.com/8898 Reviewed-by: Ian Lance Taylor <iant@golang.org> Run-TryBot: David Crawshaw <crawshaw@golang.org>
2015-04-03runtime: initialize shared library at library-load timeSrdjan Petrovic
This is Part 2 of the change, see Part 1 here: in https://go-review.googlesource.com/#/c/7692/ Suggested by iant@, we use the library initialization entry point to: - create a new OS thread and run the "regular" runtime init stack on that thread - return immediately from the main (i.e., loader) thread - at the first CGO invocation, we wait for the runtime initialization to complete. The above mechanism is implemented only on linux_amd64. Next step is to support it on linux_arm. Other platforms don't yet support shared library compiling/linking, but we intend to use the same strategy there as well. Change-Id: Ib2c81b1b83bee837134084b75a3beecfb8de6bf4 Reviewed-on: https://go-review.googlesource.com/8094 Run-TryBot: Srdjan Petrovic <spetrovic@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
2015-03-30runtime: make "write barriers are not allowed" comments more preciseAustin Clements
Currently, various functions are marked with the comment // May run without a P, so write barriers are not allowed. However, "running without a P" is ambiguous. We intended these to mean that m.p may be nil (which is the condition checked by the write barrier). The comment could also be taken to mean that a stop-the-world may happen, which is not the case for these functions because they run in situations where there is in fact a function on the stack holding a P locally, it just isn't in m.p. Change these comments to state precisely what we mean, that m.p may be nil. Change-Id: I4a4a1d26aebd455e5067540e13b9f96a7482146c Reviewed-on: https://go-review.googlesource.com/8209 Reviewed-by: Minux Ma <minux@golang.org> Reviewed-by: Rick Hudson <rlh@golang.org>
2015-03-26runtime: disallow write barriers in handoffp and calleesAustin Clements
handoffp by definition runs without a P, so it's not allowed to have write barriers. It doesn't have any right now, but mark it nowritebarrier to disallow any creeping in in the future. handoffp in turns calls startm, newm, and newosproc, all of which are "below Go" and make sense to run without a P, so disallow write barriers in these as well. For most functions, we've done this because they may race with stoptheworld() and hence must not have write barriers. For these functions, it's a little different: the world can't stop while we're in handoffp, so this race isn't present. But we implement this restriction with a somewhat broader rule that you can't have a write barrier without a P. We like this rule because it's simple and means that our write barriers can depend on there being a P, even though this rule is actually a little broader than necessary. Hence, even though there's no danger of the race in these functions, we want to adhere to the broader rule. Change-Id: Ie22319c30eea37d703eb52f5c7ca5da872030b88 Reviewed-on: https://go-review.googlesource.com/8130 Run-TryBot: Austin Clements <austin@google.com> Reviewed-by: Minux Ma <minux@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rick Hudson <rlh@golang.org>
2015-01-09runtime: use urandom instead of randomKeith Randall
Random is bad, it can block and prevent binaries from starting. Use urandom instead. We'd rather have bad random bits than no random bits. Change-Id: I360e1cb90ace5518a1b51708822a1dae27071ebd Reviewed-on: https://go-review.googlesource.com/2582 Reviewed-by: Dave Cheney <dave@cheney.net> Reviewed-by: Minux Ma <minux@golang.org>
2014-12-28runtime: rename gothrow to throwKeith Randall
Rename "gothrow" to "throw" now that the C version of "throw" is no longer needed. This change is purely mechanical except in panic.go where the old version of "throw" has been deleted. sed -i "" 's/[[:<:]]gothrow[[:>:]]/throw/g' runtime/*.go Change-Id: Icf0752299c35958b92870a97111c67bcd9159dc3 Reviewed-on: https://go-review.googlesource.com/2150 Reviewed-by: Minux Ma <minux@golang.org> Reviewed-by: Dave Cheney <dave@cheney.net>
2014-12-23runtime: run libc SIGSETXID and SIGCANCEL handlers on signal stackAustin Clements
These signals are used by glibc to broadcast setuid/setgid to all threads and to send pthread cancellations. Unlike other signals, the Go runtime does not intercept these because they must invoke the libc handlers (see issues #3871 and #6997). However, because 1) these signals may be issued asynchronously by a thread running C code to another thread running Go code and 2) glibc does not set SA_ONSTACK for its handlers, glibc's signal handler may be run on a Go stack. Signal frames range from 1.5K on amd64 to many kilobytes on ppc64, so this may overflow the Go stack and corrupt heap (or other stack) data. Fix this by ensuring that these signal handlers have the SA_ONSTACK flag (but not otherwise taking over the handler). This has been a problem since Go 1.1, but it's likely that people haven't encountered it because it only affects setuid/setgid and pthread_cancel. Fixes #9600. Change-Id: I6cf5f5c2d3aa48998d632f61f1ddc2778dcfd300 Reviewed-on: https://go-review.googlesource.com/1887 Reviewed-by: Ian Lance Taylor <iant@golang.org>
2014-12-10runtime: clean up & go-ify the hash function seederKeith Randall
Change-Id: I0e95f8a5962c547da20e19a356ae1cf8375c9107 Reviewed-on: https://go-review.googlesource.com/1270 Reviewed-by: Russ Cox <rsc@golang.org>
2014-11-14[dev.cc] runtime: change set_sec to take int64Russ Cox
Fixes build. Tested that all these systems can make.bash. TBR=austin CC=golang-codereviews https://golang.org/cl/177770043
2014-11-14[dev.cc] runtime: fix linux buildRuss Cox
TBR=austin CC=golang-codereviews https://golang.org/cl/176760044
2014-11-14[dev.cc] all: merge dev.power64 (7667e41f3ced) into dev.ccRuss Cox
This is to reduce the delta between dev.cc and dev.garbage to just garbage collector changes. These are the files that had merge conflicts and have been edited by hand: malloc.go mem_linux.go mgc.go os1_linux.go proc1.go panic1.go runtime1.go LGTM=austin R=austin CC=golang-codereviews https://golang.org/cl/174180043
2014-11-12[dev.cc] runtime: delete scalararg, ptrarg; rename onM to systemstackRuss Cox
Scalararg and ptrarg are not "signal safe". Go code filling them out can be interrupted by a signal, and then the signal handler runs, and if it also ends up in Go code that uses scalararg or ptrarg, now the old values have been smashed. For the pieces of code that do need to run in a signal handler, we introduced onM_signalok, which is really just onM except that the _signalok is meant to convey that the caller asserts that scalarg and ptrarg will be restored to their old values after the call (instead of the usual behavior, zeroing them). Scalararg and ptrarg are also untyped and therefore error-prone. Go code can always pass a closure instead of using scalararg and ptrarg; they were only really necessary for C code. And there's no more C code. For all these reasons, delete scalararg and ptrarg, converting the few remaining references to use closures. Once those are gone, there is no need for a distinction between onM and onM_signalok, so replace both with a single function equivalent to the current onM_signalok (that is, it can be called on any of the curg, g0, and gsignal stacks). The name onM and the phrase 'm stack' are misnomers, because on most system an M has two system stacks: the main thread stack and the signal handling stack. Correct the misnomer by naming the replacement function systemstack. Fix a few references to "M stack" in code. The main motivation for this change is to eliminate scalararg/ptrarg. Rick and I have already seen them cause problems because the calling sequence m.ptrarg[0] = p is a heap pointer assignment, so it gets a write barrier. The write barrier also uses onM, so it has all the same problems as if it were being invoked by a signal handler. We worked around this by saving and restoring the old values and by calling onM_signalok, but there's no point in keeping this nice home for bugs around any longer. This CL also changes funcline to return the file name as a result instead of filling in a passed-in *string. (The *string signature is left over from when the code was written in and called from C.) That's arguably an unrelated change, except that once I had done the ptrarg/scalararg/onM cleanup I started getting false positives about the *string argument escaping (not allowed in package runtime). The compiler is wrong, but the easiest fix is to write the code like Go code instead of like C code. I am a bit worried that the compiler is wrong because of some use of uninitialized memory in the escape analysis. If that's the reason, it will go away when we convert the compiler to Go. (And if not, we'll debug it the next time.) LGTM=khr R=r, khr CC=austin, golang-codereviews, iant, rlh https://golang.org/cl/174950043
2014-11-11[dev.cc] runtime: convert operating system support code from C to GoRuss Cox
The conversion was done with an automated tool and then modified only as necessary to make it compile and run. [This CL is part of the removal of C code from package runtime. See golang.org/s/dev.cc for an overview.] LGTM=r R=r CC=austin, dvyukov, golang-codereviews, iant, khr https://golang.org/cl/174830044