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2403 Commits

Author SHA1 Message Date
Austin Clements
b49b71ae19 runtime: don't rescan globals
Currently the runtime rescans globals during mark 2 and mark
termination. This costs as much as 500µs/MB in STW time, which is
enough to surpass the 10ms STW limit with only 20MB of globals.

It's also basically unnecessary. The compiler already generates write
barriers for global -> heap pointer updates and the regular write
barrier doesn't check whether the slot is a global or in the heap.
Some less common write barriers do cause problems.
heapBitsBulkBarrier, which is used by typedmemmove and related
functions, currently depends on having access to the pointer bitmap
and as a result ignores writes to globals. Likewise, the
reflect-related write barriers reflect_typedmemmovepartial and
callwritebarrier ignore non-heap destinations; though it appears they
can never be called with global pointers anyway.

This commit makes heapBitsBulkBarrier issue write barriers for writes
to global pointers using the data and BSS pointer bitmaps, removes the
inheap checks from the reflection write barriers, and eliminates the
rescans during mark 2 and mark termination. It also adds a test that
writes to globals have write barriers.

Programs with large data+BSS segments (with pointers) aren't common,
but for programs that do have large data+BSS segments, this
significantly reduces pause time:

name \ 95%ile-time/markTerm              old         new  delta
LargeBSS/bss:1GB/gomaxprocs:4  148200µs ± 6%  302µs ±52%  -99.80% (p=0.008 n=5+5)

This very slightly improves the go1 benchmarks:

name                      old time/op    new time/op    delta
BinaryTree17-12              2.62s ± 3%     2.62s ± 4%    ~     (p=0.904 n=20+20)
Fannkuch11-12                2.15s ± 1%     2.13s ± 0%  -1.29%  (p=0.000 n=18+20)
FmtFprintfEmpty-12          48.3ns ± 2%    47.6ns ± 1%  -1.52%  (p=0.000 n=20+16)
FmtFprintfString-12          152ns ± 0%     152ns ± 1%    ~     (p=0.725 n=18+18)
FmtFprintfInt-12             150ns ± 1%     149ns ± 1%  -1.14%  (p=0.000 n=19+20)
FmtFprintfIntInt-12          250ns ± 0%     244ns ± 1%  -2.12%  (p=0.000 n=20+18)
FmtFprintfPrefixedInt-12     219ns ± 1%     217ns ± 1%  -1.20%  (p=0.000 n=19+20)
FmtFprintfFloat-12           280ns ± 0%     281ns ± 1%  +0.47%  (p=0.000 n=19+19)
FmtManyArgs-12               928ns ± 0%     923ns ± 1%  -0.53%  (p=0.000 n=19+18)
GobDecode-12                7.21ms ± 1%    7.24ms ± 2%    ~     (p=0.091 n=19+19)
GobEncode-12                6.07ms ± 1%    6.05ms ± 1%  -0.36%  (p=0.002 n=20+17)
Gzip-12                      265ms ± 1%     265ms ± 1%    ~     (p=0.496 n=20+19)
Gunzip-12                   39.6ms ± 1%    39.3ms ± 1%  -0.85%  (p=0.000 n=19+19)
HTTPClientServer-12         74.0µs ± 2%    73.8µs ± 1%    ~     (p=0.569 n=20+19)
JSONEncode-12               15.4ms ± 1%    15.3ms ± 1%  -0.25%  (p=0.049 n=17+17)
JSONDecode-12               53.7ms ± 2%    53.0ms ± 1%  -1.29%  (p=0.000 n=18+17)
Mandelbrot200-12            3.97ms ± 1%    3.97ms ± 0%    ~     (p=0.072 n=17+18)
GoParse-12                  3.35ms ± 2%    3.36ms ± 1%  +0.51%  (p=0.005 n=18+20)
RegexpMatchEasy0_32-12      72.7ns ± 2%    72.2ns ± 1%  -0.70%  (p=0.005 n=19+19)
RegexpMatchEasy0_1K-12       246ns ± 1%     245ns ± 0%  -0.60%  (p=0.000 n=18+16)
RegexpMatchEasy1_32-12      72.8ns ± 1%    72.5ns ± 1%  -0.37%  (p=0.011 n=18+18)
RegexpMatchEasy1_1K-12       380ns ± 1%     385ns ± 1%  +1.34%  (p=0.000 n=20+19)
RegexpMatchMedium_32-12      115ns ± 2%     115ns ± 1%  +0.44%  (p=0.047 n=20+20)
RegexpMatchMedium_1K-12     35.4µs ± 1%    35.5µs ± 1%    ~     (p=0.079 n=18+19)
RegexpMatchHard_32-12       1.83µs ± 0%    1.80µs ± 1%  -1.76%  (p=0.000 n=18+18)
RegexpMatchHard_1K-12       55.1µs ± 0%    54.3µs ± 1%  -1.42%  (p=0.000 n=18+19)
Revcomp-12                   386ms ± 1%     381ms ± 1%  -1.14%  (p=0.000 n=18+18)
Template-12                 61.5ms ± 2%    61.5ms ± 2%    ~     (p=0.647 n=19+20)
TimeParse-12                 338ns ± 0%     336ns ± 1%  -0.72%  (p=0.000 n=14+19)
TimeFormat-12                350ns ± 0%     357ns ± 0%  +2.05%  (p=0.000 n=19+18)
[Geo mean]                  55.3µs         55.0µs       -0.41%

Change-Id: I57e8720385a1b991aeebd111b6874354308e2a6b
Reviewed-on: https://go-review.googlesource.com/20829
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Rick Hudson <rlh@golang.org>
2016-04-27 18:48:16 +00:00
Zhongwei Yao
74a9bad638 cmd/compile: enable const division for arm64
performance:
benchmark                   old ns/op     new ns/op     delta
BenchmarkDivconstI64-8      8.28          2.70          -67.39%
BenchmarkDivconstU64-8      8.28          4.69          -43.36%
BenchmarkDivconstI32-8      8.28          6.39          -22.83%
BenchmarkDivconstU32-8      8.28          4.43          -46.50%
BenchmarkDivconstI16-8      5.17          5.17          +0.00%
BenchmarkDivconstU16-8      5.33          5.34          +0.19%
BenchmarkDivconstI8-8       3.50          3.50          +0.00%
BenchmarkDivconstU8-8       3.51          3.50          -0.28%

Fixes #15382

Change-Id: Ibce7b28f0586d593b33c4d4ecc5d5e7e7c905d13
Reviewed-on: https://go-review.googlesource.com/22292
Reviewed-by: Michael Munday <munday@ca.ibm.com>
Reviewed-by: David Chase <drchase@google.com>
2016-04-27 17:47:49 +00:00
Matthew Dempsky
e48a2958d1 cmd/compile: treat empty and absent struct field tags as identical
Fixes #15439.

Change-Id: I5a32384c46e20f8db6968e5a9e854c45ab262fe4
Reviewed-on: https://go-review.googlesource.com/22429
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-25 21:28:45 +00:00
Alexandru Moșoi
8b92397bcd cmd/compile: introduce bool operations.
Introduce OrB, EqB, NeqB, AndB to handle bool operations.

Change-Id: I53e4d5125a8090d5eeb4576db619103f19fff58d
Reviewed-on: https://go-review.googlesource.com/22412
Reviewed-by: Keith Randall <khr@golang.org>
2016-04-25 20:43:04 +00:00
Josh Bleecher Snyder
9dcbc43f4f test: add test for issue 15084
The underlying issues have been fixed.
All the individual fixes have their own tests,
but it's still useful to have a plain source test.

Fixes #15084

Change-Id: I06c485a7d0716201bd57d1f3be53668dddd7ec14
Reviewed-on: https://go-review.googlesource.com/22426
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-04-25 19:20:40 +00:00
Josh Bleecher Snyder
3de87bc4d9 test: add test that required algs get generated
This is a follow-up to CLs 19769 and 19770.

Change-Id: Ia9b71055613b80df4ce62b34fcc4f479f04f72fd
Reviewed-on: https://go-review.googlesource.com/22399
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-04-24 21:36:52 +00:00
Keith Randall
934c359964 cmd/compile: reorder how slicelit initializes a slice
func f(x, y, z *int) {
    a := []*int{x,y,z}
    ...
  }

We used to use:
  var tmp [3]*int
  a := tmp[:]
  a[0] = x
  a[1] = y
  a[2] = z

Now we do:
  var tmp [3]*int
  tmp[0] = x
  tmp[1] = y
  tmp[2] = z
  a := tmp[:]

Doesn't sound like a big deal, but the compiler has trouble
eliminating write barriers when using the former method because it
doesn't know that the slice points to the stack.  In the latter
method, the compiler knows the array is on the stack and as a result
doesn't emit any write barriers.

This turns out to be extremely common when building ... args, like
for calls fmt.Printf.

Makes go binaries ~1% smaller.

Doesn't have a measurable effect on the go1 fmt benchmarks,
unfortunately.

Fixes #14263
Update #6853

Change-Id: I9074a2788ec9e561a75f3b71c119b69f304d6ba2
Reviewed-on: https://go-review.googlesource.com/22395
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-04-24 18:15:41 +00:00
Alexandru Moșoi
caef4496fc cmd/compile: convert some Phis into And8.
See discussion at [1]. True value must have a fixed non-zero
representation meaning that a && b can be implemented as a & b.

[1] https://groups.google.com/forum/#!topic/golang-dev/xV0vPuFP9Vg

This change helps with m := a && b, but it's more common to see
if a && b { do something } which is not handled.

Change-Id: Ib6f9ff898a0a8c05d12466e2464e4fe781035394
Reviewed-on: https://go-review.googlesource.com/22313
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-04-22 17:22:03 +00:00
Keith Randall
3c1a4c1902 cmd/compile: don't nilcheck newobject and return values from mapaccess{1,2}
They are guaranteed to be non-nil, no point in inserting
nil checks for them.

Fixes #15390

Change-Id: I3b9a0f2319affc2139dcc446d0a56c6785ae5a86
Reviewed-on: https://go-review.googlesource.com/22291
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-04-22 16:18:42 +00:00
Tal Shprecher
75b886ab79 cmd/compile: reject embedded unsafe.Pointer values
Fixes #14729

Change-Id: Ied819aa7b23e25de30aa8cde049c97297b4cab11
Reviewed-on: https://go-review.googlesource.com/22325
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-21 00:32:01 +00:00
David Crawshaw
7acb642e4f test: print output on link -X failure
(Split out from CL 22205.)

Change-Id: Iab66ac2a1cd3716966d8e59c570931bce95aba9b
Reviewed-on: https://go-review.googlesource.com/22297
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-04-20 17:37:35 +00:00
Alexandru Moșoi
8b20fd000d cmd/compile: transform some Phis into Or8.
func f(a, b bool) bool {
          return a || b
}

is now a single instructions (excluding loading and unloading the arguments):
      v10 = ORB <bool> v11 v12 : AX

Change-Id: Iff63399410cb46909f4318ea1c3f45a029f4aa5e
Reviewed-on: https://go-review.googlesource.com/21872
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
2016-04-19 22:04:30 +00:00
Ian Lance Taylor
f5423a63df cmd/compile: a dot expression can not be a struct literal key
Passes toolstash -cmp.

Fixes #15311.

Change-Id: I1d67f5c9de38e899ab2d6c8986fabd6f197df23a
Reviewed-on: https://go-review.googlesource.com/22162
Reviewed-by: David Crawshaw <crawshaw@golang.org>
2016-04-18 15:09:47 +00:00
Keith Randall
ac8127d7e6 cmd/compile: fix register size for ODOTPTR result
The result of ODOTPTR, as well as a bunch of other ops,
should be the type of the result, not always a pointer type.

This fixes an amd64p32 bug where we were incorrectly truncating
a 64-bit slice index to 32 bits, and then barfing on a weird
load-64-bits-but-then-truncate-to-32-bits op that doesn't exist.

Fixes #15252

Change-Id: Ie62f4315fffd79f233e5449324ccc0879f5ac343
Reviewed-on: https://go-review.googlesource.com/22094
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-14 21:19:12 +00:00
Josh Bleecher Snyder
644493f109 cmd/compile: clear hidden value at end of channel range body
While we’re here, clean up a few comments.

Fixes #15281

Change-Id: Ia6173e9941133db08f57bc80bdd3c5722122bfdb
Reviewed-on: https://go-review.googlesource.com/22082
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-04-14 19:20:26 +00:00
Michael Munday
24bd465bca test: use correct value in error message in init1.go
Print numGC followed by numGC1, rather than printing numGC twice.

Change-Id: I8e7144b6a11d4ae9be0d82d88b86fed04b906e2f
Reviewed-on: https://go-review.googlesource.com/22087
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-04-14 18:35:09 +00:00
Tal Shprecher
24967ec122 cmd/compile: make enqueued map keys fail validation on forward types
Map keys are currently validated in multiple locations but share
a common validation routine. The problem is that early validations
should be lenient enough to allow for forward types while the final
validations should not. The final validations should fail on forward
types since they've already settled.

This change also separates the key type checking from the creation
of the map via typMap. Instead of the mapqueue being populated in
copytype() by checking the map line number, it's populated in the
same block that validates the key type. This isolates key validation
logic while type checking.

Fixes #14988

Change-Id: Ia47cf6213585d6c63b3a35249104c0439feae658
Reviewed-on: https://go-review.googlesource.com/21830
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-13 08:43:12 +00:00
Matthew Dempsky
0e01db4b8d cmd/compile: fix crash on bare package name in constant declarations
Fixes #11361.

Change-Id: I70b8808f97f0e07de680e7e6ede1322ea0fdbbc0
Reviewed-on: https://go-review.googlesource.com/21936
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-04-13 06:37:39 +00:00
Alexandru Moșoi
6c6089b3fd cmd/compile: bce when max and limit are consts
Removes 49 more bound checks in make.bash. For example:

var a[100]int
for i := 0; i < 50; i++ {
  use a[i+25]
}

Change-Id: I85e0130ee5d07f0ece9b17044bba1a2047414ce7
Reviewed-on: https://go-review.googlesource.com/21379
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-11 16:01:22 +00:00
David Chase
c3b3e7b4ef cmd/compile: insert instrumentation more carefully in racewalk
Be more careful about inserting instrumentation in racewalk.
If the node being instrumented is an OAS, and it has a non-
empty Ninit, then append instrumentation to the Ninit list
rather than letting it be inserted before the OAS (and the
compilation of its init list).  This deals with the case that
the Ninit list defines a variable used in the RHS of the OAS.

Fixes #15091.

Change-Id: Iac91696d9104d07f0bf1bd3499bbf56b2e1ef073
Reviewed-on: https://go-review.googlesource.com/21771
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: David Chase <drchase@google.com>
2016-04-08 21:06:39 +00:00
Michael Munday
dae98d5c3b test: skip nilptr3 test on s390x
Fails for the same reason as ppc64 and mips64 (incomplete
optimization).

Change-Id: Ieb4d997fc27d4f2b756e63dd7f588abe10c0213a
Reviewed-on: https://go-review.googlesource.com/20963
Reviewed-by: Bill O'Farrell <billotosyr@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-04-08 17:51:46 +00:00
Keith Randall
68ac1f7746 cmd/compile: Fix constant-folding of unsigned shifts
Make sure the results of unsigned constant-folded
shifts are sign-extended into the AuxInt field.

Fixes #15175

Change-Id: I3490d1bc3d9b2e1578ed30964645508577894f58
Reviewed-on: https://go-review.googlesource.com/21586
Reviewed-by: Alexandru Moșoi <alexandru@mosoi.ro>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-07 21:39:32 +00:00
Alexandru Moșoi
8448d3aace cmd/compile: fold CMPconst and SHR
Fold the comparison when the SHR result is small.

Useful for:
- murmur mix like hashing where higher bits are desirable, i.e. hash = uint32(i * C) >> 18
- integer log2 via DeBruijn sequence: http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogDeBruijn

Change-Id: If70ae18cb86f4cc83ab6213f88ced03cc4986156
Reviewed-on: https://go-review.googlesource.com/21514
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-04-07 13:28:13 +00:00
Richard Miller
a25e368f44 test: make goprint.go wait for goroutine termination
Test goprint.go sometimes failed on a slow builder (plan9_arm)
because of timing dependency.  Instead of sleeping for a fixed
time to allow the child goroutine to finish, wait explicitly for
child termination by calling runtime.NumGoroutine until the
returned value is 1.

Fixes #15097

Change-Id: Ib3ef5ec3c8277083c774542f48bcd4ff2f79efde
Reviewed-on: https://go-review.googlesource.com/21603
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
2016-04-06 18:45:00 +00:00
Keith Randall
309144b7f1 cmd/compile: fix x=x assignments
No point in doing anything for x=x assignments.
In addition, skipping these assignments prevents generating:
    VARDEF x
    COPY x -> x
which is bad because x is incorrectly considered
dead before the vardef.

Fixes #14904

Change-Id: I6817055ec20bcc34a9648617e0439505ee355f82
Reviewed-on: https://go-review.googlesource.com/21470
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
2016-04-06 15:04:32 +00:00
David Chase
d8c815d8b5 cmd/compile: note escape of parts of closured-capture vars
Missed a case for closure calls (OCALLFUNC && indirect) in
esc.go:esccall.

Cleanup to runtime code for windows to more thoroughly hide
a technical escape.  Also made code pickier about failing
to late non-optional kernel32.dll.

Fixes #14409.

Change-Id: Ie75486a2c8626c4583224e02e4872c2875f7bca5
Reviewed-on: https://go-review.googlesource.com/20102
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-04-05 18:10:09 +00:00
Alexandru Moșoi
1747788c56 cmd/compile: add a pass to print bound checks
Since BCE happens over several passes (opt, loopbce, prove)
it's easy to regress especially with rewriting.

The pass is only activated with special debug flag.

Change-Id: I46205982e7a2751156db8e875d69af6138068f59
Reviewed-on: https://go-review.googlesource.com/21510
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-04-05 12:46:59 +00:00
Caio Marcelo de Oliveira Filho
f229e46783 cmd/compile: better error when assigning to struct field in map
Identify this assignment case and instead of the more general error

    prog.go:6: cannot assign to students["sally"].age

produce

    prog.go:6: cannot directly assign to struct field students["sally"].age in map

that explains why the assignment is not possible.

Fixes #13779.

Change-Id: I90c10b445f907834fc1735aa66e44a0f447aa74f
Reviewed-on: https://go-review.googlesource.com/21462
Reviewed-by: David Chase <drchase@google.com>
2016-04-04 14:07:47 +00:00
Eric Engestrom
7a8caf7d43 all: fix spelling mistakes
Signed-off-by: Eric Engestrom <eric@engestrom.ch>

Change-Id: I91873aaebf79bdf1c00d38aacc1a1fb8d79656a7
Reviewed-on: https://go-review.googlesource.com/21433
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-04-03 17:03:15 +00:00
Alexandru Moșoi
27ebc84716 cmd/compile: handle non-negatives in prove
Handle this case:
if 0 <= i && i < len(a) {
        use a[i]
}

Shaves about 5k from pkg/tools/linux_amd64/*.

Change-Id: I6675ff49aa306b0d241b074c5738e448204cd981
Reviewed-on: https://go-review.googlesource.com/21431
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-04-02 20:34:38 +00:00
Todd Neal
ac8d97b679 cmd/compile: fix inlining of switch issue
The issue was seen when inlining an exported function that contained
a fallthrough statement.

Fixes #15071

Change-Id: I1e8215ad49d57673dba7e8f8bd2ed8ad290dc452
Reviewed-on: https://go-review.googlesource.com/21452
Reviewed-by: Dave Cheney <dave@cheney.net>
2016-04-02 12:38:00 +00:00
Alexandru Moșoi
b91cc53033 cmd/compile/internal/ssa: BCE for induction variables
There are 5293 loop in the main go repository.
A survey of the top most common for loops:

     18 for __k__ := 0; i < len(sa.Addr); i++ {
     19 for __k__ := 0; ; i++ {
     19 for __k__ := 0; i < 16; i++ {
     25 for __k__ := 0; i < length; i++ {
     30 for __k__ := 0; i < 8; i++ {
     49 for __k__ := 0; i < len(s); i++ {
     67 for __k__ := 0; i < n; i++ {
    376 for __k__ := range __slice__ {
    685 for __k__, __v__ := range __slice__ {
   2074 for __, __v__ := range __slice__ {

The algorithm to find induction variables handles all cases
with an upper limit. It currently doesn't find related induction
variables such as c * ind or c + ind.

842 out of 22954 bound checks are removed for src/make.bash.
1957 out of 42952 bounds checks are removed for src/all.bash.

Things to do in follow-up CLs:
* Find the associated pointer for `for _, v := range a {}`
* Drop the NilChecks on the pointer.
* Replace the implicit induction variable by a loop over the pointer

Generated garbage can be reduced if we share the sdom between passes.

% benchstat old.txt new.txt
name       old time/op     new time/op     delta
Template       337ms ± 3%      333ms ± 3%    ~             (p=0.258 n=9+9)
GoTypes        1.11s ± 2%      1.10s ± 2%    ~           (p=0.912 n=10+10)
Compiler       5.25s ± 1%      5.29s ± 2%    ~             (p=0.077 n=9+9)
MakeBash       33.5s ± 1%      34.1s ± 2%  +1.85%          (p=0.011 n=9+9)

name       old alloc/op    new alloc/op    delta
Template      63.6MB ± 0%     63.9MB ± 0%  +0.52%         (p=0.000 n=10+9)
GoTypes        218MB ± 0%      219MB ± 0%  +0.59%         (p=0.000 n=10+9)
Compiler       978MB ± 0%      985MB ± 0%  +0.69%        (p=0.000 n=10+10)

name       old allocs/op   new allocs/op   delta
Template        582k ± 0%       583k ± 0%  +0.10%        (p=0.000 n=10+10)
GoTypes        1.78M ± 0%      1.78M ± 0%  +0.12%        (p=0.000 n=10+10)
Compiler       7.68M ± 0%      7.69M ± 0%  +0.05%        (p=0.000 n=10+10)

name       old text-bytes  new text-bytes  delta
HelloSize       581k ± 0%       581k ± 0%  -0.08%        (p=0.000 n=10+10)
CmdGoSize      6.40M ± 0%      6.39M ± 0%  -0.08%        (p=0.000 n=10+10)

name       old data-bytes  new data-bytes  delta
HelloSize      3.66k ± 0%      3.66k ± 0%    ~     (all samples are equal)
CmdGoSize       134k ± 0%       134k ± 0%    ~     (all samples are equal)

name       old bss-bytes   new bss-bytes   delta
HelloSize       126k ± 0%       126k ± 0%    ~     (all samples are equal)
CmdGoSize       149k ± 0%       149k ± 0%    ~     (all samples are equal)

name       old exe-bytes   new exe-bytes   delta
HelloSize       947k ± 0%       946k ± 0%  -0.01%        (p=0.000 n=10+10)
CmdGoSize      9.92M ± 0%      9.91M ± 0%  -0.06%        (p=0.000 n=10+10)

Change-Id: Ie74bdff46fd602db41bb457333d3a762a0c3dc4d
Reviewed-on: https://go-review.googlesource.com/20517
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
2016-04-01 09:37:58 +00:00
David Chase
b64f549ba9 cmd/compile: ignore OXXX nodes in closure captured vars list
Added a debug flag "-d closure" to explain compilation of
closures (should this be done some other way? Should we
rewrite the "-m" flag to "-d escapes"?)  Used this to
discover that cause was an OXXX node in the captured vars
list, and in turn noticed that OXXX nodes are explicitly
ignored in all other processing of captured variables.

Couldn't figure out a reproducer, did verify that this OXXX
was not caused by an unnamed return value (which is one use
of these).  Verified lack of heap allocation by examining -S
output.

Assembly:
(runtime/mgc.go:1371) PCDATA $0, $2
(runtime/mgc.go:1371) CALL "".notewakeup(SB)
(runtime/mgc.go:1377) LEAQ "".gcBgMarkWorker.func1·f(SB), AX
(runtime/mgc.go:1404) MOVQ AX, (SP)
(runtime/mgc.go:1404) MOVQ "".autotmp_2242+88(SP), CX
(runtime/mgc.go:1404) MOVQ CX, 8(SP)
(runtime/mgc.go:1404) LEAQ go.string."GC worker (idle)"(SB), AX
(runtime/mgc.go:1404) MOVQ AX, 16(SP)
(runtime/mgc.go:1404) MOVQ $16, 24(SP)
(runtime/mgc.go:1404) MOVB $20, 32(SP)
(runtime/mgc.go:1404) MOVQ $0, 40(SP)
(runtime/mgc.go:1404) PCDATA $0, $2
(runtime/mgc.go:1404) CALL "".gopark(SB)

Added a check for compiling_runtime to ensure that this is
caught in the future.  Added a test to test the check.
Verified that 1.5.3 did NOT reject the test case when
compiled with -+ flag, so this is not a recently added bug.

Cause of bug is two-part -- there was no leaking closure
detection ever, and instead it relied on capture-of-variables
to trigger compiling_runtime test, but closures improved in
1.5.3 so that mere capture of a value did not also capture
the variable, which thus allowed closures to escape, as well
as this case where the escape was spurious.  In
fixedbugs/issue14999.go, compare messages for f and g;
1.5.3 would reject g, but not f.  1.4 rejects both because
1.4 heap-allocates parameter x for both.

Fixes #14999.

Change-Id: I40bcdd27056810628e96763a44f2acddd503aee1
Reviewed-on: https://go-review.googlesource.com/21322
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
2016-04-01 02:08:56 +00:00
Ian Lance Taylor
92bb694a49 cmd/compile: s.f aliases itself
The change in 20907 fixed varexpr but broke aliased.  After that change,
a reference to a field in a struct would not be seen as aliasing itself.
Before that change, it would, but only because all fields in a struct
aliased everything.

This CL changes the compiler to consider all references to a field as
aliasing all other fields in that struct.  This is imperfect--a
reference to one field does not alias another field--but is a simple fix
for the immediate problem.  A better fix would require tracking the
specific fields as well.

Fixes #15042.

Change-Id: I5c95c0dd7b0699e53022fce9bae2e8f50d6d1d04
Reviewed-on: https://go-review.googlesource.com/21390
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
2016-04-01 00:47:56 +00:00
Keith Randall
4a7aba775d cmd/compile: better job of naming compound types
Compound AUTO types weren't named previously.  That was because live
variable analysis (plive.go) doesn't handle spilling to compound types.
It can't handle them because there is no valid place to put VARDEFs when
regalloc is spilling compound types.

compound types = multiword builtin types: complex, string, slice, and
interface.

Instead, we split named AUTOs into individual one-word variables.  For
example, a string s gets split into a byte ptr s.ptr and an integer
s.len.  Those two variables can be spilled to / restored from
independently.  As a result, live variable analysis can handle them
because they are one-word objects.

This CL will change how AUTOs are described in DWARF information.
Consider the code:

func f(s string, i int) int {
    x := s[i:i+5]
    g()
    return lookup(x)
}

The old compiler would spill x to two consecutive slots on the stack,
both named x (at offsets 0 and 8).  The new compiler spills the pointer
of x to a slot named x.ptr.  It doesn't spill x.len at all, as it is a
constant (5) and can be rematerialized for the call to lookup.

So compound objects may not be spilled in their entirety, and even if
they are they won't necessarily be contiguous.  Such is the price of
optimization.

Re-enable live variable analysis tests.  One test remains disabled, it
fails because of #14904.

Change-Id: I8ef2b5ab91e43a0d2136bfc231c05d100ec0b801
Reviewed-on: https://go-review.googlesource.com/21233
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2016-03-31 22:18:26 +00:00
Keith Randall
47c9e139ae cmd/compile: extend prove pass to handle constant comparisons
Find comparisons to constants and propagate that information
down the dominator tree.  Use it to resolve other constant
comparisons on the same variable.

So if we know x >= 7, then a x > 4 condition must return true.

This change allows us to use "_ = b[7]" hints to eliminate bounds checks.

Fixes #14900

Change-Id: Idbf230bd5b7da43de3ecb48706e21cf01bf812f7
Reviewed-on: https://go-review.googlesource.com/21008
Reviewed-by: Alexandru Moșoi <alexandru@mosoi.ro>
2016-03-31 21:16:23 +00:00
Keith Randall
4b95575bd4 cmd/compile: fix build
Pushed from an old client by mistake.  These are the
missing changes.

Change-Id: Ia8d61c5c0bde907369366ea9ea98711823342803
Reviewed-on: https://go-review.googlesource.com/21349
Reviewed-by: Todd Neal <todd@tneal.org>
2016-03-31 18:00:36 +00:00
Keith Randall
b81f2f106f cmd/compile: place combined loads at the location of the last byte load
We need to make sure all the bounds checks pass before issuing
a load which combines several others.  We do this by issuing the
combined load at the last load's block, where "last" = closest to
the leaf of the dominator tree.

Fixes #15002

Change-Id: I7358116db1e039a072c12c0a73d861f3815d72af
Reviewed-on: https://go-review.googlesource.com/21246
Reviewed-by: Todd Neal <todd@tneal.org>
2016-03-31 17:21:33 +00:00
Matthew Dempsky
e6066711a0 cmd/compile, runtime: fix pedantic int->string conversions
Previously, cmd/compile rejected constant int->string conversions if
the integer value did not fit into an "int" value. Also, runtime
incorrectly truncated 64-bit values to 32-bit before checking if
they're a valid Unicode code point. According to the Go spec, both of
these cases should instead yield "\uFFFD".

Fixes #15039.

Change-Id: I3c8a3ad9a0780c0a8dc1911386a523800fec9764
Reviewed-on: https://go-review.googlesource.com/21344
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-31 10:28:23 +00:00
Brad Fitzpatrick
758447cdc9 test/fixedbugs: add test for divide by zero being optimized away
This only tests amd64 because it's currently broken on non-SSA
backends.

Fixes #8613

Change-Id: I6bc501c81c395e533bb9c7335789750e0c6b7a8f
Reviewed-on: https://go-review.googlesource.com/21325
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-31 06:12:38 +00:00
Alexandru Moșoi
d8f1f8d856 cmd/compile: generalize strength reduction of mulq
* This is an improved version of an earlier patch.
* Verified with gcc up to 100.
* Limited to two instructions based on costs from
https://gmplib.org/~tege/x86-timing.pdf

Change-Id: Ib7c37de6fd8e0ba554459b15c7409508cbcf6728
Reviewed-on: https://go-review.googlesource.com/21103
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Alexandru Moșoi <alexandru@mosoi.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-30 22:27:13 +00:00
Ian Lance Taylor
777a77b4d2 cmd/compile: don't skip PPARAMOUT in esccall after varargs
Fixes bug I introduced in CL 21202.

Fixes #15013.

Change-Id: I2344d7e22b8273425a0a56f4a77588b5c6e4d8c6
Reviewed-on: https://go-review.googlesource.com/21270
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-30 02:43:08 +00:00
David Chase
8eec2bbfbc cmd/compile: added some intrinsics to SSA back end
One intrinsic was needed to help get the very best
performance out of a future GC; as long as that one was
being added, I also added Bswap since that is sometimes
a handy thing to have.  I had intended to fill out the
bit-scan intrinsic family, but the mismatch between the
"scan forward" instruction and "count leading zeroes"
was large enough to cause me to leave it out -- it poses
a dilemma that I'd rather dodge right now.

These intrinsics are not exposed for general use.
That's a separate issue requiring an API proposal change
( https://github.com/golang/proposal )

All intrinsics are tested, both that they are substituted
on the appropriate architecture, and that they produce the
expected result.

Change-Id: I5848037cfd97de4f75bdc33bdd89bba00af4a8ee
Reviewed-on: https://go-review.googlesource.com/20564
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-28 16:29:59 +00:00
Robert Griesemer
c12e1b0b2e cmd/compile: update vendored math/big to latest version
This makes the rounding bug fix in math/big for issue 14651 available
to the compiler.

- changes to cmd/compile/internal/big fully automatic via script
- added test case for issue
- updated old test case with correct test data

Fixes #14651.

Change-Id: Iea37a2cd8d3a75f8c96193748b66156a987bbe40
Reviewed-on: https://go-review.googlesource.com/20818
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-22 17:09:29 +00:00
Keith Randall
d4663e1353 cmd/compile: don't write back unchanged slice results
Don't write back parts of a slicing operation if they
are unchanged from the source of the slice.  For example:

x.s = x.s[0:5]         // don't write back pointer or cap
x.s = x.s[:5]          // don't write back pointer or cap
x.s = x.s[:5:7]        // don't write back pointer

There is more to be done here, for example:

x.s = x.s[:len(x.s):7] // don't write back ptr or len

This CL can't handle that one yet.

Fixes #14855

Change-Id: Id1e1a4fa7f3076dc1a76924a7f1cd791b81909bb
Reviewed-on: https://go-review.googlesource.com/20954
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
2016-03-21 23:40:18 +00:00
Todd Neal
e41f527f4d cmd/compile: allow inlining of functions with switch statements
Allow inlining of functions with switch statements as long as they don't
contain a break or type switch.

Fixes #13071

Change-Id: I057be351ea4584def1a744ee87eafa5df47a7f6d
Reviewed-on: https://go-review.googlesource.com/20824
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2016-03-21 23:05:10 +00:00
Michael Munday
4402ee9fa3 test: add s390x case to nosplit test
Fixes this test on s390x.

Change-Id: Ie5b70e8191169867765ec9248d827ca12c6405f4
Reviewed-on: https://go-review.googlesource.com/20964
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-21 08:14:51 +00:00
Michael Munday
1a82946ea5 test/fixedbugs: add s390x case to issue11656
An instruction consisting of all 0s causes an illegal instruction
signal on s390x. Since 0s are the default in this test this CL just
makes it explicit.

Change-Id: Id6e060eed1a588f4b10a4e4861709fcd19b434ac
Reviewed-on: https://go-review.googlesource.com/20962
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
2016-03-21 07:09:36 +00:00
Todd Neal
fc6bcdee79 cmd/compile: allow inlining of functions that declare a const
Consider functions with an ODCLCONST for inlining and modify exprfmt to
ignore those nodes when exporting. Don't add symbols to the export list
if there is no definition.  This occurs when OLITERAL symbols are looked
up via Pkglookup for non-exported symbols.

Fixes #7655

Change-Id: I1de827850f4c69e58107447314fe7433e378e069
Reviewed-on: https://go-review.googlesource.com/20773
Run-TryBot: Todd Neal <todd@tneal.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2016-03-18 23:26:36 +00:00
Marcel van Lohuizen
5c83e651ad testing: prepare for the introduction of Run methods
The biggest change is that each test is now responsible for managing
the starting and stopping of its parallel subtests.

The "Main" test could be run as a tRunner as well. This shows that
the introduction of subtests is merely a generalization of and
consistent with the current semantics.

Change-Id: Ibf8388c08f85d4b2c0df69c069326762ed36a72e
Reviewed-on: https://go-review.googlesource.com/18893
Reviewed-by: Russ Cox <rsc@golang.org>
2016-03-18 11:25:54 +00:00