go, branch go1.12beta1

runtime: use QPC for nanotime and time.now on windows/arm

2018-12-18T23:01:06Z

The previous implementation of nanotime and time.now used a time source that was updated on the system clock tick, which has a maximum resolution of about 1ms. On 386 and amd64, this time source maps to the system performance counter, so has much higher resolution. On ARM, use QueryPerformanceCounter() to get a high resolution timestamp. Updates #26148 Change-Id: I1abc99baf927a95b472ac05020a7788626c71d08 Reviewed-on: https://go-review.googlesource.com/c/154758 Reviewed-by: Brad Fitzpatrick Run-TryBot: Brad Fitzpatrick TryBot-Result: Gobot Gobot

doc/go1.12: note that syscall.Getdirentries is no longer supported on iOS

2018-12-18T22:40:56Z

Change-Id: I4277f4130b460b42c5b51fd5a5e07f6c0e62163b Reviewed-on: https://go-review.googlesource.com/c/154720 Reviewed-by: Ian Lance Taylor

api: promote next to go1.12

2018-12-18T21:27:51Z

Change-Id: I9a30c76d1299a494cce69b1060156bc2932ac8d5 Reviewed-on: https://go-review.googlesource.com/c/154857 Reviewed-by: Dmitri Shuralyov Reviewed-by: Ian Lance Taylor Reviewed-by: Brad Fitzpatrick Run-TryBot: Dmitri Shuralyov TryBot-Result: Gobot Gobot

os: show how to print permission bits in octal

2018-12-18T21:17:16Z

Permission bits are most commonly viewed in string form (rwx-- etc) or in octal form (0755), but the latter is relatively rare in Go. Demonstrate how to print a FileMode in readable octal format. Change-Id: I41feb801bcecb5077d4eabafdea27c149fc179a1 Reviewed-on: https://go-review.googlesource.com/c/154423 Run-TryBot: Ian Lance Taylor Reviewed-by: Ian Lance Taylor Reviewed-by: Brad Fitzpatrick

runtime: call mmap with MAP_FIXED on BSDs in race mode

2018-12-18T21:05:05Z

This change makes it so that reserving more of the address space for the heap calls mmap with MAP_FIXED in race mode. Race mode requires certain guarantees on where the heap is located in the address space, and on Darwin 10.10 it appears that the kernel may end up ignoring the hint quite often (#26475). Using MAP_FIXED is relatively OK in race mode because nothing else should be mapped in the memory region provided by the initial hints. Fixes #26475. Change-Id: Id7ac1534ee74f6de491bc04441f27dbda09f0285 Reviewed-on: https://go-review.googlesource.com/c/153897 Reviewed-by: Austin Clements Run-TryBot: Austin Clements TryBot-Result: Gobot Gobot

cmd/cover: avoid repeating positions

2018-12-18T20:57:18Z

When using //line directives and unformatted code it is possible for positions to repeat. Increment the final column position to avoid that. Fixes #27350 Change-Id: I2faccc31360075e9814d4a024b0f98b117f8ce97 Reviewed-on: https://go-review.googlesource.com/c/153061 Run-TryBot: Rob Pike Reviewed-by: Rob Pike

cmd/cover: use -toolexec in tests to run newly built cover program

2018-12-18T20:55:57Z

This ensures that "go test cmd/cover" tests the current cover program, not the installed cover program. Change-Id: I58e718ded7eb1cd8da448d0194262209bb025b20 Reviewed-on: https://go-review.googlesource.com/c/153058 Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot Reviewed-by: Brad Fitzpatrick

cmd/dist: enable race detector test on Linux/ARM64

2018-12-18T20:50:43Z

CL 138675 added the race detector support on Linux/ARM64, but it didn't enable the race detector tests in cmd/dist (therefore in all.bash). Enable them. Updates #28848 Change-Id: I4306dad2fb4167021d568436076b9f535d7f6e07 Reviewed-on: https://go-review.googlesource.com/c/149967 Run-TryBot: Cherry Zhang Reviewed-by: Ian Lance Taylor

doc/go1.12: finish most Go 1.12 release notes

2018-12-18T20:13:07Z

Change-Id: I598c9a2031001a6780b75c31d9015c880741b170 Reviewed-on: https://go-review.googlesource.com/c/154637 Reviewed-by: Brad Fitzpatrick

doc/go1.12: add notes for syscall/js CLs 141644, 143137, 144384

2018-12-18T16:45:33Z

Also update a Go 1 compatibility promise link to canonical URL. Updates #27592 Updates #28264 Change-Id: I5994a0a63e0870c1795c65016590dfad829d26a7 Reviewed-on: https://go-review.googlesource.com/c/154618 Reviewed-by: Richard Musiol Reviewed-by: Brad Fitzpatrick