When a map or slice is used as a return type create an empty value
rather than a nil value.
Fixes#19588
Change-Id: I577fd74956172329745d614ac37d4db8f737efb8
Reviewed-on: https://go-review.googlesource.com/38474
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Verified that BenchmarkBitLen time went down from 2.25 ns/op to 0.65 ns/op
an a 2.3 GHz Intel Core i7, before removing that benchmark (now covered by
math/bits benchmarks).
Change-Id: I3890bb7d1889e95b9a94bd68f0bdf06f1885adeb
Reviewed-on: https://go-review.googlesource.com/38464
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It is currently possible in the compiler to create a struct type,
calculate the widths of types that depend on it,
and then alter the struct type.
transformclosure has local protection against this.
Protect against it at a deeper level.
This is preparation to call dowidth automatically,
rather than explicitly.
Change-Id: Ic1578ca014610197cfe54a9f4d044d122a7217e8
Reviewed-on: https://go-review.googlesource.com/38469
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
In livenessepilogue, if we save liveness information for instructions
before updating liveout, we can avoid an extra bitvector temporary and
some extra copying around.
Passes toolstash-check -all.
Change-Id: I10d5803167ef3eba2e9e95094adc7e3d33929cc7
Reviewed-on: https://go-review.googlesource.com/38408
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
In some newer Linux distros, systemd forces
all mount namespaces to be shared, starting
at /. This disables the CLONE_NEWNS
flag in unshare(2) and clone(2).
While this problem is most commonly seen
on systems with systemd, it can happen anywhere,
due to how Linux namespaces now work.
Hence, to create a private mount namespace,
it is not sufficient to just set
CLONE_NEWS; you have to call mount(2) to change
the behavior of namespaces, i.e.
mount("none", "/", NULL, MS_REC|MS_PRIVATE, NULL)
This is tested and working and we can now correctly
start child process with private namespaces on Linux
distros that use systemd.
The new test works correctly on Ubuntu 16.04.2 LTS.
It fails if I comment out the new Mount, and
succeeds otherwise. In each case it correctly
cleans up after itself.
Fixes#19661
Change-Id: I52240b59628e3772b529d9bbef7166606b0c157d
Reviewed-on: https://go-review.googlesource.com/38471
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
A -0 constant is the same as 0. Use explicit negative zero
for float64 -0.0. Also, fix two test cases that were wrong.
Fixes#19673.
Change-Id: Ic09775f29d9bc2ee7814172e59c4a693441ea730
Reviewed-on: https://go-review.googlesource.com/38463
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
CL 38337 modified canMergeLoad to reject loads with multiple uses
so it is no longer necessary to check this in the SSA rules.
Change-Id: I03498390e778da1be8cb59ae0948e99289008315
Reviewed-on: https://go-review.googlesource.com/38473
Run-TryBot: Michael Munday <munday@ca.ibm.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Introduce a new type, gc.Progs, to manage
generation of Progs for a function.
Use it to replace globals pc and pcloc.
Passes toolstash-check -all.
Updates #15756
Change-Id: I2206998d7c58fe2a76b620904909f2e1cec8a57d
Reviewed-on: https://go-review.googlesource.com/38418
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Regalloc uses loop depths - make sure they are initialized!
Test to make sure we aren't pushing spills into loops.
This fixes a generated-code performance bug introduced with
the better spill placement change:
https://go-review.googlesource.com/c/34822/
Update #19595
Change-Id: Ib9f0da6fb588503518847d7aab51e569fd3fa61e
Reviewed-on: https://go-review.googlesource.com/38434
Reviewed-by: David Chase <drchase@google.com>
We want to merge a load and op into a single instruction
l = LOAD ptr mem
y = OP x l
into
y = OPload x ptr mem
However, all of our OPload instructions require that y uses
the same register as x. If x is needed past this instruction, then
we must copy x somewhere else, losing the whole benefit of merging
the instructions in the first place.
Disable this optimization if x is live past the OP.
Also disable this optimization if the OP is in a deeper loop than the load.
Update #19595
Change-Id: I87f596aad7e91c9127bfb4705cbae47106e1e77a
Reviewed-on: https://go-review.googlesource.com/38337
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
As #19357 reported,
TST has 3 different sub forms
TST $imme, Rx
TST Ry << imme, Rx
TST Ry << Rz, Rx
just like CMP/CMN/TEQ has. But current arm assembler assembles all TST
instructions wrongly. This patch fixes it and adds more tests.
Fixes#19357
Change-Id: Iafedccfaab2cbb2631e7acf259837a782e2e8e2f
Reviewed-on: https://go-review.googlesource.com/37662
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
It was already marked flaky for everything but the dashboard.
Remove that restriction. It's just flaky overall.
It's doing more harm than good.
Updates #13324
Change-Id: I36feff32a1b8681e77700f74b9c70cb4073268eb
Reviewed-on: https://go-review.googlesource.com/38459
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
exporter.nesting was added in c7b9bd74 to mitigate #16369 which was
closed in ee272bbf. Remove the exporter.nesting field as it is now unused.
Change-Id: I07873d1a07d6a08b11994b817a1483ffc2f5e45f
Reviewed-on: https://go-review.googlesource.com/38490
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
CL 38446 introduced the use of the sys.ArchFamily type into the
cmd/internal/obj/mips package and redefined the mips.Mips32 and
mips.Mips64 constants in terms of their sys.ArchFamily counterparts.
This CL removes these local declarations and consolidates on sys.MIPS
and sys.MIPS64 respectively.
Change-Id: Id7aab6c7fd0de42ff43dde605df6bd4c85a3d895
Reviewed-on: https://go-review.googlesource.com/38287
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The step method implementations check directly if the next rune
only needs one byte to be decoded and avoid calling utf8.DecodeRune
for such ASCII characters.
Introduce the same fast path optimization for rune decoding
for the context methods.
Results for regexp benchmarks that use the context methods:
name old time/op new time/op delta
AnchoredLiteralShortNonMatch-4 97.5ns ± 1% 94.8ns ± 2% -2.80% (p=0.000 n=45+43)
AnchoredShortMatch-4 163ns ± 1% 160ns ± 1% -1.84% (p=0.000 n=46+47)
NotOnePassShortA-4 742ns ± 2% 742ns ± 2% ~ (p=0.440 n=49+50)
NotOnePassShortB-4 535ns ± 1% 533ns ± 2% -0.37% (p=0.005 n=46+48)
OnePassLongPrefix-4 169ns ± 2% 166ns ± 2% -2.06% (p=0.000 n=50+49)
Change-Id: Ib302d9e8c63333f02695369fcf9963974362e335
Reviewed-on: https://go-review.googlesource.com/38256
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This greatly improves the latency of starting a child process when
the Go process is using a lot of memory. Even though the kernel uses
copy-on-write, preparation for that can take up to several 100ms under
certain conditions. All other goroutines are suspended while starting
a subprocess so this latency directly affects total throughput.
With CLONE_VM the child process shares the same memory with the parent
process. On its own this would lead to conflicting use of the same
memory, so CLONE_VFORK is used to suspend the parent process until the
child releases the memory when switching to to the new program binary
via the exec syscall. When the parent process continues to run, one
has to consider the changes to memory that the child process did,
namely the return address of the syscall function needs to be restored
from a register.
A simple benchmark has shown a difference in latency of 16ms vs. 0.5ms
at 10GB memory usage. However, much higher latencies of several 100ms
have been observed in real world scenarios. For more information see
comments on #5838.
Fixes#5838
Change-Id: I6377d7bd8dcd00c85ca0c52b6683e70ce2174ba6
Reviewed-on: https://go-review.googlesource.com/37439
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
When unmarshaling, if an element is empty, eg. '<tag></tag>', and
destination type is int, uint, float or bool, do not attempt to parse
value (""). Set to its zero value instead.
Fixes#13417
Change-Id: I2d79f6d8f39192bb277b1a9129727d5abbb2dd1f
Reviewed-on: https://go-review.googlesource.com/38386
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The DefaultServeMux included in net/http uses a map to store routes,
but iterates all keys for every request to allow longer paths.
This change checks the map for an exact match first.
To check performance was better, BenchmarkServeMux has been added -
this adds >100 routes and checks the matches.
Exact matches are faster and more predictable on this benchmark
and on most existing package benchmarks.
https://perf.golang.org/search?q=upload:20170312.1
ServeMux-4 2.02ms ± 2% 0.04ms ± 2% −98.08% (p=0.004 n=5+6)
https://perf.golang.org/search?q=upload:20170312.2
ReadRequestChrome-4 184MB/s ± 8% 186MB/s ± 1% ~
ReadRequestCurl-4 45.0MB/s ± 1% 46.2MB/s ± 1% +2.71%
Read...Apachebench-4 45.8MB/s ±13% 48.7MB/s ± 1% ~
ReadRequestSiege-4 63.6MB/s ± 5% 69.2MB/s ± 1% +8.75%
ReadRequestWrk-4 30.9MB/s ± 9% 34.4MB/s ± 2% +11.25%
Change-Id: I8afafcb956f07197419d545a9f1c03ecaa307384
Reviewed-on: https://go-review.googlesource.com/38057
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This simplifies the code and removes a premature optimization.
It increases the amount of allocated syntax.Node space by ~0.4%
for parsing all of std lib, which is negligible.
Before the change (best of 5 runs):
$ go test -run StdLib -fast
parsed 1517022 lines (3394 files) in 793.487886ms (1911840 lines/s)
allocated 387.086Mb (267B/line, 487.828Mb/s)
After the change (best of 5 runs):
$ go test -run StdLib -fast
parsed 1516911 lines (3392 files) in 805.028655ms (1884294 lines/s)
allocated 388.466Mb (268B/line, 482.549Mb/s)
Change-Id: Id19d6210fdc62393862ba3b04913352d95c599be
Reviewed-on: https://go-review.googlesource.com/38439
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This change adds position information for { and } braces in the
source. There's a 1.9% increase in memory use for syntax.Nodes,
which is negligible relative to overall compiler memory consumption.
Parsing the std library (using syntax package only) and memory
consumption before this change (fastest of 5 runs):
$ go test -run StdLib -fast
parsed 1516827 lines (3392 files) in 780.612335ms (1943124 lines/s)
allocated 379.903Mb (486.673Mb/s)
After this change (fastest of 5 runs):
$ go test -run StdLib -fast
parsed 1517022 lines (3394 files) in 793.487886ms (1911840 lines/s)
allocated 387.086Mb (267B/line, 487.828Mb/s)
While not an exact apples-to-apples comparison (the syntax package
has changed and is also parsed), the overall impact is small.
Also: Small improvements to nodes_test.go.
Change-Id: Ib8a7f90bbe79de33d83684e33b1bf8dbc32e644a
Reviewed-on: https://go-review.googlesource.com/38435
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Change-Id: I2d155c838935cd8427abd142a462ff4c56829715
Reviewed-on: https://go-review.googlesource.com/37948
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Starting in go1.9, the minimum processor requirement for ppc64 is POWER8.
Therefore, the checks for OldArch and the code enabled by it are not necessary
anymore.
Updates #19074
Change-Id: I33d6a78b2462c80d57c5dbcba2e13424630afab4
Reviewed-on: https://go-review.googlesource.com/38404
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Starting in go1.9, the minimum processor requirement for ppc64 is POWER8. This
means the checks for GOARCH_ppc64 in asm_ppc64x.s can be removed, since we can
assume LBAR and STBCCC instructions (both from ISA 2.06) will always be
available.
Updates #19074
Change-Id: Ib4418169cd9fc6f871a5ab126b28ee58a2f349e2
Reviewed-on: https://go-review.googlesource.com/38406
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Asmode is always set to p.Mode,
which is always set based on the arch family.
Instead, use the arch family directly.
Passes toolstash-check -all.
Change-Id: Id982472dcc8eeb6dd22cac5ad2f116b54a44caee
Reviewed-on: https://go-review.googlesource.com/38451
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Replace Ctxt.Mode with a method, Ctxt.RegWidth,
which is calculated directly off the arch info.
I believe that Prog.Mode can also be removed; future CL.
This is a step towards obj.Link immutability.
Passes toolstash-check -all.
Updates #15756
Change-Id: Ifd7f8f6ed0a2fdc032d1dd306fcd695a14aa5bc5
Reviewed-on: https://go-review.googlesource.com/38446
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TestOnlyWriteTimeout assumes wrongly that:
- the Accept method of trackLastConnListener is called only once
- the shared variable conn never becomes nil
and crashes on some circumstances.
Updates #19032.
Change-Id: I61de22618cd90b84a2b6401afdb6e5d9b3336b12
Reviewed-on: https://go-review.googlesource.com/36735
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
To enable this, inline the call to nod and simplify.
Eliminates a reference to lineno from the backend.
Passes toolstash-check -all.
Updates #15756
Change-Id: I9c4bd77d10d727aa8f5e6c6bb16b0e05de165631
Reviewed-on: https://go-review.googlesource.com/38441
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
AMODE appears to have been intended to allow
a Prog to switch between 16 (!), 32, or 64 bit x86.
It is unused anywhere in the tree.
Passes toolstash-check -all.
Updates #15756
Change-Id: Ic57b257cfe580f29dad81d97e4193bf3c330c598
Reviewed-on: https://go-review.googlesource.com/38445
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
By analogy with the handling of methods on types, show the documentation
for a single field of a struct.
% go doc ast.structtype.fields
struct StructType {
Fields *FieldList // list of field declarations
}
%
Fixes#19169.
Change-Id: I002f992e4aa64bee667e2e4bccc7082486149842
Reviewed-on: https://go-review.googlesource.com/38438
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
I broke FreeBSD 9 in https://golang.org/cl/38426 by using Pipe2.
We still want to support FreeBSD 9 for one last release (Go 1.9 will
be the last), and FreeBSD 9 doesn't have Pipe2.
So this still uses Pipe2, but falls back to Pipe on error.
Updates #18854
Updates #19072
Change-Id: I1de90fb83606c93fb84b4b86fba31e207a702835
Reviewed-on: https://go-review.googlesource.com/38430
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Must have been lost when rebasing the SSA liveness CLs.
Change-Id: Iaac33158cc7c92ea44a023c242eb914a7d6979c6
Reviewed-on: https://go-review.googlesource.com/38427
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
