delta/go-git.git/src/runtime/internal, branch dev.link

runtime/internal/atomic: add 32-bit And/Or

2020-10-23T14:17:57+00:00

These will be used in a following CL to perform larger bit clear and bit
set than And8/Or8.

Change-Id: I60f7b1099e29b69eb64add77564faee862880a8d
Reviewed-on: https://go-review.googlesource.com/c/go/+/260977
Run-TryBot: Michael Pratt 
TryBot-Result: Go Bot 
Reviewed-by: Cherry Zhang 
Trust: Michael Pratt

cmd/compiler,cmd/go,sync: add internal {LoadAcq,StoreRel}64 on ppc64

2020-10-21T14:34:44+00:00

Add an internal atomic intrinsic for load with acquire semantics
(extending LoadAcq to 64b) and add LoadAcquintptr for internal
use within the sync package.  For other arches, this remaps to the
appropriate atomic.Load{,64} intrinsic which should not alter code
generation.

Similarly, add StoreRel{uintptr,64} for consistency, and inline.

Finally, add an exception to allow sync to directly use the
runtime/internal/atomic package which avoids more convoluted
workarounds (contributed by Lynn Boger).

In an extreme example, sync.(*Pool).pin consumes 20% of wall time
during fmt tests.  This is reduced to 5% on ppc64le/power9.

From the fmt benchmarks on ppc64le:

name                           old time/op  new time/op  delta
SprintfPadding                  468ns ± 0%   451ns ± 0%   -3.63%
SprintfEmpty                   73.3ns ± 0%  51.9ns ± 0%  -29.20%
SprintfString                   135ns ± 0%   122ns ± 0%   -9.63%
SprintfTruncateString           232ns ± 0%   214ns ± 0%   -7.76%
SprintfTruncateBytes            216ns ± 0%   202ns ± 0%   -6.48%
SprintfSlowParsingPath          162ns ± 0%   142ns ± 0%  -12.35%
SprintfQuoteString             1.00µs ± 0%  0.99µs ± 0%   -1.39%
SprintfInt                      117ns ± 0%   104ns ± 0%  -11.11%
SprintfIntInt                   190ns ± 0%   175ns ± 0%   -7.89%
SprintfPrefixedInt              232ns ± 0%   212ns ± 0%   -8.62%
SprintfFloat                    270ns ± 0%   255ns ± 0%   -5.56%
SprintfComplex                 1.01µs ± 0%  0.99µs ± 0%   -1.68%
SprintfBoolean                  127ns ± 0%   111ns ± 0%  -12.60%
SprintfHexString                220ns ± 0%   198ns ± 0%  -10.00%
SprintfHexBytes                 261ns ± 0%   252ns ± 0%   -3.45%
SprintfBytes                    600ns ± 0%   590ns ± 0%   -1.67%
SprintfStringer                 684ns ± 0%   658ns ± 0%   -3.80%
SprintfStructure               2.57µs ± 0%  2.57µs ± 0%   -0.12%
ManyArgs                        669ns ± 0%   646ns ± 0%   -3.44%
FprintInt                       140ns ± 0%   136ns ± 0%   -2.86%
FprintfBytes                    184ns ± 0%   181ns ± 0%   -1.63%
FprintIntNoAlloc                140ns ± 0%   136ns ± 0%   -2.86%
ScanInts                        929µs ± 0%   921µs ± 0%   -0.79%
ScanRecursiveInt                122ms ± 0%   121ms ± 0%   -0.11%
ScanRecursiveIntReaderWrapper   122ms ± 0%   122ms ± 0%   -0.18%

Change-Id: I4d66780261b57b06ef600229e475462e7313f0d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/253748
Run-TryBot: Lynn Boger 
Reviewed-by: Lynn Boger 
Reviewed-by: Keith Randall 
Trust: Lynn Boger 
TryBot-Result: Go Bot

runtime/internal/atomic: panic nicely on unaligned 64-bit atomics

2020-10-16T17:31:17+00:00

On 386 and arm, unaligned 64-bit atomics aren't safe, so we check for
this and panic. Currently, we panic by dereferencing nil, which may be
expedient but is pretty user-hostile since it gives no hint of what
the actual problem was.

This CL replaces this with an actual panic. The only subtlety here is
now the atomic assembly implementations are calling back into Go, so
they have to play nicely with stack maps and stack scanning. On 386,
this just requires declaring NO_LOCAL_POINTERS. On arm, this is
somewhat more complicated: first, we have to move the alignment check
into the functions that have Go signatures. Then we have to support
both the tail call from these functions to the underlying
implementation (which requires that they have no frame) and the call
into Go to panic (which requires that they have a frame). We resolve
this by forcing them to have no frame and setting up the frame
manually just before the panic call.

Change-Id: I19f1e860045df64088013db37a18acea47342c69
Reviewed-on: https://go-review.googlesource.com/c/go/+/262778
Trust: Austin Clements 
Run-TryBot: Austin Clements 
TryBot-Result: Go Bot 
Reviewed-by: Cherry Zhang 
Reviewed-by: Michael Knyszek

runtime/internal/atomic: drop package prefixes

2020-10-16T17:31:16+00:00

This drops package prefixes from the assembly code on 386 and arm. In
addition to just being nicer, this allows the assembler to
automatically pick up the argument stack map from the Go signatures of
these functions. This doesn't matter right now because these functions
never call back out to Go, but prepares us for the next CL.

Change-Id: I90fed7d4dd63ad49274529c62804211b6390e2e9
Reviewed-on: https://go-review.googlesource.com/c/go/+/262777
Trust: Austin Clements 
Run-TryBot: Austin Clements 
TryBot-Result: Go Bot 
Reviewed-by: Cherry Zhang 
Reviewed-by: Michael Knyszek

all: add GOOS=ios

2020-09-23T18:12:59+00:00

Introduce GOOS=ios for iOS systems. GOOS=ios matches "darwin"
build tag, like GOOS=android matches "linux" and GOOS=illumos
matches "solaris". Only ios/arm64 is supported (ios/amd64 is
not).

GOOS=ios and GOOS=darwin remain essentially the same at this
point. They will diverge at later time, to differentiate macOS
and iOS.

Uses of GOOS=="darwin" are changed to (GOOS=="darwin" || GOOS=="ios"),
except if it clearly means macOS (e.g. GOOS=="darwin" && GOARCH=="amd64"),
it remains GOOS=="darwin".

Updates #38485.

Change-Id: I4faacdc1008f42434599efb3c3ad90763a83b67c
Reviewed-on: https://go-review.googlesource.com/c/go/+/254740
Trust: Cherry Zhang 
Run-TryBot: Cherry Zhang 
TryBot-Result: Go Bot 
Reviewed-by: Austin Clements

runtime: add test for StorepNoWB param leaking

2020-08-24T03:55:18+00:00

CL 249962 added wasm StorepNoWB implementation in assembly, it's now
like all other architectures. This CL adds a general test that the
second param of StorepNoWB must be force to escape.

Fixes #40975

Change-Id: I1eccc7e50a3ec742a1912d65f25b15f9f5ad9241
Reviewed-on: https://go-review.googlesource.com/c/go/+/249761
Run-TryBot: Cuong Manh Le 
TryBot-Result: Gobot Gobot 
Reviewed-by: Matthew Dempsky

runtime: implement StorepNoWB for wasm in assembly

2020-08-23T20:18:56+00:00

The second argument of StorepNoWB must be forced to escape.
The current Go code does not explicitly enforce that property.
By implementing in assembly, and not using go:noescape, we
force the issue.

Test is in CL 249761. Issue #40975.

This CL is needed for CL 249917, which changes how go:notinheap
works and breaks the previous StorepNoWB wasm code.

I checked for other possible errors like this. This is the only
go:notinheap that isn't in the runtime itself.

Change-Id: I43400a806662655727c4a3baa8902b63bdc9fa57
Reviewed-on: https://go-review.googlesource.com/c/go/+/249962
Run-TryBot: Keith Randall 
TryBot-Result: Gobot Gobot 
Reviewed-by: Matthew Dempsky

runtime: eliminate redundant load in Xchg and Xadd on arm64

2020-04-03T17:08:32+00:00

Loading arguments of Xchg(64) and Xadd(64) functions to registers
could be done only once.

Change-Id: Iaf0a695ec9c6a221dfa755855edb68c476978a5b
Reviewed-on: https://go-review.googlesource.com/c/go/+/227001
Reviewed-by: Keith Randall 
Run-TryBot: Keith Randall 
TryBot-Result: Gobot Gobot

cmd/asm,cmd/internal/obj/riscv: add atomic memory operation instructions

2020-03-15T08:13:28+00:00

Use instructions in place of currently used defines.

Updates #36765

Change-Id: I00bb59e77b1aace549d7857cc9721ba2cb4ac6ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/220541
Reviewed-by: Cherry Zhang

cmd/asm,cmd/internal/obj/riscv: add LR/SC instructions

2020-03-15T07:51:41+00:00

Add support for Load-Reserved (LR) and Store-Conditional (SC) instructions.

Use instructions in place of currently used defines.

Updates #36765

Change-Id: I77e660639802293ece40cfde4865ac237e3308d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/220540
Reviewed-by: Cherry Zhang