go, branch go1.12.2

[release-branch.go1.12] go1.12.2

2019-04-05T19:24:53Z

Change-Id: I07e4404196886b7754414726f25092cca39861a7 Reviewed-on: https://go-review.googlesource.com/c/go/+/170888 Run-TryBot: Brad Fitzpatrick Reviewed-by: Brad Fitzpatrick

[release-branch.go1.12] cmd/go: avoid link error when -coverpkg covers main packages (more)

2019-04-05T19:08:44Z

This fixes two problems missed in CL 164877. First, p.Internal.BuildInfo is now part of the cache key. This is important since p.Internal.BuildInfo causes the build action to synthesize a new source file, which affects the output. Second, recompileForTest is always called for test packages. Previously, it was only called when there were internal test sources, so the fix in CL 164877 did not apply to packages that only had external tests. Fixes #30937 Change-Id: Iac2d7e8914f0313f9ab4222299a866f67889eb2e Reviewed-on: https://go-review.googlesource.com/c/go/+/168200 Run-TryBot: Jay Conrod TryBot-Result: Gobot Gobot Reviewed-by: Ian Lance Taylor (cherry picked from commit d34548e0b6acc14a99bc6ffc225eedbb56e03d60) Reviewed-on: https://go-review.googlesource.com/c/go/+/168717 Run-TryBot: Brad Fitzpatrick Reviewed-by: Brad Fitzpatrick

[release-branch.go1.12] runtime: fix write barrier on wasm

2019-04-05T18:47:42Z

The current wasm write barrier implementation incorrectly implements the "deletion" part of the barrier. It correctly greys the new value of the pointer, but rather than also greying the old value of the pointer, it greys the object containing the slot (which, since the old value was just overwritten, is not going to contain the old value). This can lead to unmarked, reachable objects. Often, this is masked by other marking activity, but one specific sequence that can lead to an unmarked object because of this bug is: 1. Initially, GC is off, object A is reachable from just one pointer in the heap. 2. GC starts and scans the stack of goroutine G. 3. G copies the pointer to A on to its stack and overwrites the pointer to A in the heap. (Now A is reachable only from G's stack.) 4. GC finishes while A is still reachable from G's stack. With a functioning deletion barrier, step 3 causes A to be greyed. Without a functioning deletion barrier, nothing causes A to be greyed, so A will be freed even though it's still reachable from G's stack. This CL fixes the wasm write barrier. Fixes #30873. Change-Id: I8a74ee517facd3aa9ad606e5424bcf8f0d78e754 Reviewed-on: https://go-review.googlesource.com/c/go/+/167743 Run-TryBot: Austin Clements Reviewed-by: Cherry Zhang (cherry picked from commit d9db9e32e924a60bbfbb15cc0dd7cfaaf8a62a3b) Reviewed-on: https://go-review.googlesource.com/c/go/+/167745 Reviewed-by: Katie Hockman TryBot-Result: Gobot Gobot

[release-branch.go1.12] doc: document Go 1.12.2

2019-04-05T18:38:08Z

Change-Id: I990c451ff24844b39dee2477cec4caa9db2e8ebb Reviewed-on: https://go-review.googlesource.com/c/go/+/170883 Reviewed-by: Brad Fitzpatrick (cherry picked from commit 5ec938cdcf7ab59f6d397cb3fa4d17459057ef61) Reviewed-on: https://go-review.googlesource.com/c/go/+/170885 Reviewed-by: Andrew Bonventre

[release-branch.go1.12] doc: document Go 1.11.7

2019-04-05T18:37:56Z

Change-Id: Iec5e69b3ea163f42234d3b73696427a7aa8732e3 Reviewed-on: https://go-review.googlesource.com/c/go/+/170884 Reviewed-by: Brad Fitzpatrick (cherry picked from commit e47ced78578c471cbcd34a7d6b223a71e84a46c8) Reviewed-on: https://go-review.googlesource.com/c/go/+/170886 Reviewed-by: Andrew Bonventre

Revert "[release-branch.go1.12] syscall: avoid _getdirentries64 on darwin"

2019-04-05T18:15:47Z

This reverts commit 731ebf4d87dbe349e2eb60233c3965ee62a32690. Reason for revert: It's not working for large directories. Change-Id: Ie0f88e0ed1d36c4ea4f32d2acd4e223bd8229ca0 Reviewed-on: https://go-review.googlesource.com/c/go/+/170882 Reviewed-by: Emmanuel Odeke Reviewed-by: Brad Fitzpatrick Run-TryBot: Andrew Bonventre

[release-branch.go1.12] syscall: avoid _getdirentries64 on darwin

2019-04-05T16:59:48Z

Getdirentries is implemented with the __getdirentries64 function in libSystem.dylib. That function works, but it's on Apple's can't-be-used-in-an-app-store-application list. Implement Getdirentries using the underlying fdopendir/readdir_r/closedir. The simulation isn't faithful, and could be slow, but it should handle common cases. Don't use Getdirentries in the stdlib, use fdopendir/readdir_r/closedir instead (via (*os.File).readdirnames). (Incorporates CL 170837 and CL 170698, which were small fixes to the original tip CL.) Fixes #31244 Update #28984 RELNOTE=yes Change-Id: Ia6b5d003e5bfe43ba54b1e1d9cfa792cc6511717 Reviewed-on: https://go-review.googlesource.com/c/go/+/168479 Reviewed-by: Emmanuel Odeke Reviewed-by: Brad Fitzpatrick Run-TryBot: Emmanuel Odeke TryBot-Result: Gobot Gobot (cherry picked from commit 9da6530faab0a58c4c4e02b2f3f4a5c754dcbd4e) Reviewed-on: https://go-review.googlesource.com/c/go/+/170640 Run-TryBot: Brad Fitzpatrick

[release-branch.go1.12] runtime: skip broken TestLldbPython

2019-04-05T02:38:30Z

It's broken on our builders (once we enabled dev mode on our Macs, see CL 170339) Updates #31188 Change-Id: Iceea65dc79576057b401a461bfe39254fed1f7ed Reviewed-on: https://go-review.googlesource.com/c/go/+/170281 Reviewed-by: Josh Bleecher Snyder Run-TryBot: Brad Fitzpatrick (cherry picked from commit 46c3e217188043c7cea9e181f0d61825d2636ad7) Reviewed-on: https://go-review.googlesource.com/c/go/+/170798 TryBot-Result: Gobot Gobot Reviewed-by: Keith Randall

[release-branch.go1.12] internal/poll: fix deadlock in Write if len(buf) > maxRW

2019-04-04T02:24:05Z

fd.l.Lock shouldn't be called in a loop. Manual backport of CL 165598. It could not be cherry-picked due to conflicts. Fixes #31211 Change-Id: Ib76e679f6a276b32fe9c1594b7e9a506017a7967 Reviewed-on: https://go-review.googlesource.com/c/go/+/170680 Run-TryBot: Ian Lance Taylor Reviewed-by: Brad Fitzpatrick TryBot-Result: Gobot Gobot

[release-branch.go1.12] cmd/compile: fix literal struct interface {} lost passing by value

2019-04-02T19:43:35Z

CL 135377 introduces pass strings and slices to convT2{E,I} by value. Before that CL, all types, except interface will be allocated temporary address. The CL changes the logic that only constant and type which needs address (determine by convFuncName) will be allocated. It fails to cover the case where type is static composite literal. Adding condition to check that case fixes the issue. Also, static composite literal node implies constant type, so consttype checking can be removed. Fixes #31209 Change-Id: Ifc750a029fb4889c2d06e73e44bf85e6ef4ce881 Reviewed-on: https://go-review.googlesource.com/c/go/+/168858 Run-TryBot: Ian Lance Taylor TryBot-Result: Gobot Gobot Reviewed-by: Keith Randall (cherry picked from commit d47db6dc0ce72d1371c81a677b45d7bdba39ff46) Reviewed-on: https://go-review.googlesource.com/c/go/+/170437 Run-TryBot: Andrew Bonventre Reviewed-by: Cherry Zhang