delta/go-git.git, branch tls

cmd/go: report scan error position in 'go list -e'

2020-04-06T18:06:41+00:00

This CL extracts some error handling code into a common method for
presenting errors encountered when loading package data.

Fixes #36087
Fixes #36762

Change-Id: I87c8d41e3cc6e6afa152d9c067bc60923bf19fbe
Reviewed-on: https://go-review.googlesource.com/c/go/+/210938
Run-TryBot: Jay Conrod 
TryBot-Result: Gobot Gobot 
Reviewed-by: Michael Matloob 
Reviewed-by: Bryan C. Mills

cmd/link: remove darwin/arm test

2020-04-06T16:11:47+00:00

The darwin/arm port is removed in Go 1.15. Setting GOOS=darwin
GOARCH=arm will fail, therefore "go test cmd/link" on macOS will
fail (in non -short mode). Remove this test point.

Updates #37611.

Change-Id: Ia9531c4b4a6692a0c49153517af9fdddd1f3e0bf
Reviewed-on: https://go-review.googlesource.com/c/go/+/227341
Reviewed-by: Ian Lance Taylor

cmd/compile: lay out exit post-dominated blocks at the end

2020-04-06T16:08:18+00:00

Complete a long-standing TODO in the code.

Exit blocks are cold code, so we lay them out at the end of the function.
Blocks that are post-dominated by exit blocks are also ipso facto exit blocks.
Treat them as such.

Implement using a simple loop, because there are generally very few exit blocks.

In addition to improved instruction cache, this empirically yields
better register allocation.

Binary size impact:

file    before    after     Δ       %       
cgo     4812872   4808776   -4096   -0.085% 
fix     3370072   3365976   -4096   -0.122% 
vet     8252280   8248184   -4096   -0.050% 
total   115052984 115040696 -12288  -0.011% 

This also appears to improve compiler performance
(-0.15% geomean time/op, -1.20% geomean user time/op),
but that could just be alignment effects.
Compiler benchmarking hasn't been super reliably recently,
and there's no particular reason to think this should
speed up the compiler that much.

Change-Id: I3d262c4f5cb80626a67a5c17285e2fa09f423c00
Reviewed-on: https://go-review.googlesource.com/c/go/+/227217
Run-TryBot: Josh Bleecher Snyder 
TryBot-Result: Gobot Gobot 
Reviewed-by: David Chase

cmd/link: fix data race in testDWARF

2020-04-06T16:08:10+00:00

Multiple instances of testDWARF run in parallel, with a shared
backing store of the env input slice. Do modification of the
environment locally, instead of on the shared slice.

Fixes #38265.

Change-Id: I22a7194c8cd55ba22c9d6c47ac47bf7e710a7027
Reviewed-on: https://go-review.googlesource.com/c/go/+/227342
Run-TryBot: Cherry Zhang 
Reviewed-by: Ian Lance Taylor 
Reviewed-by: Josh Bleecher Snyder 
TryBot-Result: Gobot Gobot

cmd/go: report 'go get' errors for absolute paths outside module root

2020-04-06T15:59:41+00:00

'go get' will now check absolute paths without wildcards the same way
it checks relative paths. modload.DirImportPath may be used for both
without converting path separators.

Fixes #38038

Change-Id: I453299898ece58f3b5002a5e80021d6bfe815fdd
Reviewed-on: https://go-review.googlesource.com/c/go/+/226857
Run-TryBot: Jay Conrod 
TryBot-Result: Gobot Gobot 
Reviewed-by: Bryan C. Mills 
Reviewed-by: Michael Matloob

cmd/compile: make logopt test skip if cannot create scratch directory

2020-04-06T15:22:07+00:00

Fixes #38251.

Change-Id: Ic635843fb503484a1c9a230b0cca571393d3da5a
Reviewed-on: https://go-review.googlesource.com/c/go/+/227339
Run-TryBot: David Chase 
Reviewed-by: Cuong Manh Le

cmd/compile: print block auxint value in HTML output

2020-04-06T14:42:24+00:00

The auxint value was being printed in LongString() but not LongHTML().

Fixes #38250.

Change-Id: I28e819feef8710f912bee424d1b900eb07f3abb8
Reviewed-on: https://go-review.googlesource.com/c/go/+/227160
Run-TryBot: Michael Munday 
TryBot-Result: Gobot Gobot 
Reviewed-by: Cherry Zhang

cmd/compile: improve lowered moves and zeros for ppc64le

2020-04-06T12:09:39+00:00

This change includes the following:
- Generate LXV/STXV sequences instead of LXVD2X/STXVD2X on power9.
These instructions do not require an index register, which
allows more loads and stores within a loop without initializing
multiple index registers. The LoweredQuadXXX generate LXV/STXV.
- Create LoweredMoveXXXShort and LoweredZeroXXXShort for short
moves that don't generate loops, and therefore don't clobber the
address registers or flags.
- Use registers other than R3 and R4 to avoid conflicting with
registers that have already been allocated to avoid unnecessary
register moves.
- Eliminate the use of R14 as scratch register and use R31
instead.
- Add PCALIGN when the LoweredMoveXXX or LoweredZeroXXX generates a
loop with more than 3 iterations.

This performance opportunity was noticed in github.com/golang/snappy
benchmarks. Results on power9:

WordsDecode1e1    54.1ns ± 0%    53.8ns ± 0%   -0.51%  (p=0.029 n=4+4)
WordsDecode1e2     287ns ± 0%     282ns ± 1%   -1.83%  (p=0.029 n=4+4)
WordsDecode1e3    3.98µs ± 0%    3.64µs ± 0%   -8.52%  (p=0.029 n=4+4)
WordsDecode1e4    66.9µs ± 0%    67.0µs ± 0%   +0.20%  (p=0.029 n=4+4)
WordsDecode1e5     723µs ± 0%     723µs ± 0%   -0.01%  (p=0.200 n=4+4)
WordsDecode1e6    7.21ms ± 0%    7.21ms ± 0%   -0.02%  (p=1.000 n=4+4)
WordsEncode1e1    29.9ns ± 0%    29.4ns ± 0%   -1.51%  (p=0.029 n=4+4)
WordsEncode1e2    2.12µs ± 0%    1.75µs ± 0%  -17.70%  (p=0.029 n=4+4)
WordsEncode1e3    11.7µs ± 0%    11.2µs ± 0%   -4.61%  (p=0.029 n=4+4)
WordsEncode1e4     119µs ± 0%     120µs ± 0%   +0.36%  (p=0.029 n=4+4)
WordsEncode1e5    1.21ms ± 0%    1.22ms ± 0%   +0.41%  (p=0.029 n=4+4)
WordsEncode1e6    12.0ms ± 0%    12.0ms ± 0%   +0.57%  (p=0.029 n=4+4)
RandomEncode       286µs ± 0%     203µs ± 0%  -28.82%  (p=0.029 n=4+4)
ExtendMatch       47.4µs ± 0%    47.0µs ± 0%   -0.85%  (p=0.029 n=4+4)

Change-Id: Iecad3a39ae55280286e42760a5c9d5c1168f5858
Reviewed-on: https://go-review.googlesource.com/c/go/+/226539
Run-TryBot: Lynn Boger 
TryBot-Result: Gobot Gobot 
Reviewed-by: Cherry Zhang

time, runtime: only call resetTimer from (*Timer).Reset

2020-04-06T03:35:33+00:00

Previously we stopped the timer and then reset it. With the current
timer implementation that is no longer required.

Change-Id: Ie7aba61ad53ce835f6fcd0b6bce7fe0a15b10e24
Reviewed-on: https://go-review.googlesource.com/c/go/+/227180
Run-TryBot: Ian Lance Taylor 
TryBot-Result: Gobot Gobot 
Reviewed-by: Michael Knyszek

cmd/compile: restore missing columns in ssa.html

2020-04-05T23:23:03+00:00

If the final pass(es) are identical during ssa.html generation,
they are persisted in-memory as "pendingPhases" but never get
written as a column in the html. This change flushes those
in-memory phases.

Fixes #38242

Change-Id: Id13477dcbe7b419a818bb457861b2422ba5ef4bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/227182
Reviewed-by: Josh Bleecher Snyder 
Run-TryBot: Josh Bleecher Snyder 
TryBot-Result: Gobot Gobot