Change-Id: I25db1d637dd461cec67ba70659d523b46895c113
Reviewed-on: https://go-review.googlesource.com/38744Reviewed-by: Alan Donovan <adonovan@google.com>

rsc.io/toolstash is gone; use rsc.io/pprof_mac_fix.

This fixes a bug in the test. It turns out the code being tested here
is also broken, so the test still doesn't pass after this CL (filed #19769).

Change-Id: Ieb725c321d7fab600708e133ae28f531e55521ad
Reviewed-on: https://go-review.googlesource.com/38743Reviewed-by: Alan Donovan <adonovan@google.com>

The uintptr-typed Data field in reflect.SliceHeader and
reflect.StringHeader needs special treatment because it is
really a pointer.  Add the special treatment in walk for
bug #19168 to escape analysis.

Includes extra debugging that was helpful.

Fixes #19743.

Change-Id: I6dab5002f0d436c3b2a7cdc0156e4fc48a43d6fe
Reviewed-on: https://go-review.googlesource.com/38738
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Previously, an inlined call to wg.Done() in package main would have the
following incorrect symbol name:

    main.(*sync.WaitGroup).Done

This change modifies methodname to return the correct symbol name:

    sync.(*WaitGroup).Done

This fix was suggested by @mdempsky.

Fixes #19467.

Change-Id: I0117838679ac5353789299c618ff8c326712d94d
Reviewed-on: https://go-review.googlesource.com/37866Reviewed-by: Austin Clements <austin@google.com>

Change-Id: If1a3396175f2afa607d56efd1444181334a9ae3e
Reviewed-on: https://go-review.googlesource.com/37862Reviewed-by: Austin Clements <austin@google.com>

The `skip` argument passed to runtime.Caller and runtime.Callers should
be interpreted as the number of logical calls to skip (rather than the
number of physical stack frames to skip). This changes runtime.Callers
to skip inlined calls in addition to physical stack frames.

The result value of runtime.Callers is a slice of program counters
([]uintptr) representing physical stack frames. If the `skip` parameter
to runtime.Callers skips part-way into a physical frame, there is no
convenient way to encode that in the resulting slice. To avoid changing
the API in an incompatible way, our solution is to store the number of
skipped logical calls of the first frame in the _second_ uintptr
returned by runtime.Callers. Since this number is a small integer, we
encode it as a valid PC value into a small symbol called:

    runtime.skipPleaseUseCallersFrames

For example, if f() calls g(), g() calls `runtime.Callers(2, pcs)`, and
g() is inlined into f, then the frame for f will be partially skipped,
resulting in the following slice:

    pcs = []uintptr{pc_in_f, runtime.skipPleaseUseCallersFrames+1, ...}

We store the skip PC in pcs[1] instead of pcs[0] so that `pcs[i:]` will
truncate the captured stack trace rather than grow it for all i.

Updates #19348.

Change-Id: I1c56f89ac48c29e6f52a5d085567c6d77d499cf1
Reviewed-on: https://go-review.googlesource.com/37854
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Previously, we could not run tests with -l=4 on NaCl since the buildrun
action is not supported on NaCl. This lets us run tests with build flags
on NaCl.

Change-Id: I103370c7b823b4ff46f47df97e802da0dc2bc7c3
Reviewed-on: https://go-review.googlesource.com/38170
Run-TryBot: David Lazar <lazard@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Fixes #19753.

Change-Id: Ib20a69b1d0bcc42aa9e924918bcb578d6a560a31
Reviewed-on: https://go-review.googlesource.com/38742
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The aLongTimeAgo time value in net and net/http is used to cancel
in-flight read and writes. It was set to time.Unix(233431200, 0)
which seemed like far enough in the past.

But Raspberry Pis, lacking a real time clock, had to spoil the fun and
boot in 1970 at the Unix epoch time, breaking assumptions in net and
net/http.

So change aLongTimeAgo to time.Unix(1, 0), which seems like the
earliest safe value. I don't trust subsecond values on all operating
systems, and I don't trust the Unix zero time. The Raspberry Pis do
advance their clock at least. And the reported problem was that Hijack
on a ResponseWriter hung forever, waiting for the connection read
operation to finish. So now, even if kernel + userspace boots in under
a second (unlikely), the Hijack will just have to wait for up to a
second.

Fixes #19747

Change-Id: Id59430de2e7b5b5117d4903a788863e9d344e53a
Reviewed-on: https://go-review.googlesource.com/38785
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

We have lots of rewrite rules that vary only in the fact that
we have 2 versions for the 2 different orderings of various
commuting ops. For example:

(ADDL x (MOVLconst [c])) -> (ADDLconst [c] x)
(ADDL (MOVLconst [c]) x) -> (ADDLconst [c] x)

It can get unwieldly quickly, especially when there is more than
one commuting op in a rule.

Our existing "fix" for this problem is to have rules that
canonicalize the operations first. For example:

(Eq64 x (Const64 <t> [c])) && x.Op != OpConst64 -> (Eq64 (Const64 <t> [c]) x)

Subsequent rules can then assume if there is a constant arg to Eq64,
it will be the first one. This fix kinda works, but it is fragile and
only works when we remember to include the required extra rules.

The fundamental problem is that the rule matcher doesn't
know anything about commuting ops. This CL fixes that fact.

We already have information about which ops commute. (The register
allocator takes advantage of commutivity.)  The rule generator now
automatically generates multiple rules for a single source rule when
there are commutative ops in the rule. We can now drop all of our
almost-duplicate source-level rules and the canonicalization rules.

I have some CLs in progress that will be a lot less verbose when
the rule generator handles commutivity for me.

I had to reorganize the load-combining rules a bit. The 8-way OR rules
generated 128 different reorderings, which was causing the generator
to put too much code in the rewrite*.go files (the big ones were going
from 25K lines to 132K lines). Instead I reorganized the rules to
combine pairs of loads at a time. The generated rule files are now
actually a bit (5%) smaller.
[Note to reviewers: check these carefully. Most of the other rule
changes are trivial.]

Make.bash times are ~unchanged.

Compiler benchmarks are not observably different. Probably because
we don't spend much compiler time in rule matching anyway.

I've also done a pass over all of our ops adding commutative markings
for ops which hadn't had them previously.

Fixes #18292

Change-Id: I999b1307272e91965b66754576019dedcbe7527a
Reviewed-on: https://go-review.googlesource.com/38666
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

reflect.callReflect heap-allocates a stack frame and then constructs
pointers to the arguments and result areas of that frame. However, if
there are no results, the results pointer will point past the end of
the frame allocation. If there are also no arguments, the arguments
pointer will also point past the end of the frame allocation. If the
GC observes either these pointers, it may panic.

Fix this by not constructing these pointers if these areas of the
frame are empty.

This adds a test of calling no-argument/no-result methods via reflect,
since nothing in std did this before. However, it's quite difficult to
demonstrate the actual failure because it depends on both exact
allocation patterns and on GC scanning the goroutine's stack while
inside one of the typedmemmovepartial calls.

I also audited other uses of typedmemmovepartial and
memclrNoHeapPointers in reflect, since these are the most susceptible
to this. These appear to be the only two cases that can construct
out-of-bounds arguments to these functions.

Fixes #19724.

Change-Id: I4b83c596b5625dc4ad0567b1e281bad4faef972b
Reviewed-on: https://go-review.googlesource.com/38736
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Currently for spans with up to 1 MBytes (128 pages) we
maintain an array indexed by the number of pages in the
span. This is efficient both in terms of space as well
as time to insert or remove a span of a particular size.

Unfortunately for spans larger than 1 MByte we currently
place them on a separate linked list. This results in
O(n) behavior. Now that we are seeing heaps approaching
100 GBytes n is large enough to be noticed in real programs.

This change replaces the linked list now used with a balanced
binary tree structure called a treap. A treap is a
probabilistically balanced tree offering O(logN) behavior for
inserting and removing spans.

To verify that this approach will work we start with noting
that only spans with sizes > 1MByte will be put into the treap.
This means that to support 1 TByte a treap will need at most
1 million nodes and can ideally be held in a treap with a
depth of 20. Experiments with adding and removing randomly
sized spans from the treap seem to result in treaps with
depths of about twice the ideal or 40. A petabyte would
require a tree of only twice again that depth again so this
algorithm should last well into the future.

Fixes #19393

Go1 benchmarks indicate this is basically an overall wash.
Tue Mar 28 21:29:21 EDT 2017
name                     old time/op    new time/op    delta
BinaryTree17-4              2.42s ± 1%     2.42s ± 1%    ~     (p=0.980 n=21+21)
Fannkuch11-4                3.00s ± 1%     3.18s ± 4%  +6.10%  (p=0.000 n=22+24)
FmtFprintfEmpty-4          40.5ns ± 1%    40.3ns ± 3%    ~     (p=0.692 n=22+25)
FmtFprintfString-4         65.9ns ± 3%    64.6ns ± 1%  -1.98%  (p=0.000 n=24+23)
FmtFprintfInt-4            69.6ns ± 1%    68.0ns ± 7%  -2.30%  (p=0.001 n=21+22)
FmtFprintfIntInt-4          102ns ± 2%      99ns ± 1%  -3.07%  (p=0.000 n=23+23)
FmtFprintfPrefixedInt-4     126ns ± 0%     125ns ± 0%  -0.79%  (p=0.000 n=19+17)
FmtFprintfFloat-4           206ns ± 2%     205ns ± 1%    ~     (p=0.671 n=23+21)
FmtManyArgs-4               441ns ± 1%     445ns ± 1%  +0.88%  (p=0.000 n=22+23)
GobDecode-4                5.73ms ± 1%    5.86ms ± 1%  +2.37%  (p=0.000 n=23+22)
GobEncode-4                4.51ms ± 1%    4.89ms ± 1%  +8.32%  (p=0.000 n=22+22)
Gzip-4                      197ms ± 0%     202ms ± 1%  +2.75%  (p=0.000 n=23+24)
Gunzip-4                   32.9ms ± 8%    32.7ms ± 2%    ~     (p=0.466 n=23+24)
HTTPClientServer-4         57.3µs ± 1%    56.7µs ± 1%  -0.94%  (p=0.000 n=21+22)
JSONEncode-4               13.8ms ± 1%    13.9ms ± 2%  +1.14%  (p=0.000 n=22+23)
JSONDecode-4               47.4ms ± 1%    48.1ms ± 1%  +1.49%  (p=0.000 n=23+23)
Mandelbrot200-4            3.92ms ± 0%    3.92ms ± 1%  +0.21%  (p=0.000 n=22+22)
GoParse-4                  2.89ms ± 1%    2.87ms ± 1%  -0.68%  (p=0.000 n=21+22)
RegexpMatchEasy0_32-4      73.6ns ± 1%    72.0ns ± 2%  -2.15%  (p=0.000 n=21+22)
RegexpMatchEasy0_1K-4       173ns ± 1%     173ns ± 1%    ~     (p=0.847 n=22+24)
RegexpMatchEasy1_32-4      71.9ns ± 1%    69.8ns ± 1%  -2.99%  (p=0.000 n=23+20)
RegexpMatchEasy1_1K-4       314ns ± 1%     308ns ± 1%  -1.91%  (p=0.000 n=22+23)
RegexpMatchMedium_32-4      106ns ± 0%     105ns ± 1%  -0.58%  (p=0.000 n=19+21)
RegexpMatchMedium_1K-4     34.3µs ± 1%    34.3µs ± 1%    ~     (p=0.871 n=23+22)
RegexpMatchHard_32-4       1.67µs ± 1%    1.67µs ± 7%    ~     (p=0.224 n=22+23)
RegexpMatchHard_1K-4       51.5µs ± 1%    50.4µs ± 1%  -1.99%  (p=0.000 n=22+23)
Revcomp-4                   383ms ± 1%     415ms ± 0%  +8.51%  (p=0.000 n=22+22)
Template-4                 51.5ms ± 1%    51.5ms ± 1%    ~     (p=0.555 n=20+23)
TimeParse-4                 279ns ± 2%     277ns ± 1%  -0.95%  (p=0.000 n=24+22)
TimeFormat-4                294ns ± 1%     296ns ± 1%  +0.58%  (p=0.003 n=24+23)
[Geo mean]                 43.7µs         43.8µs       +0.32%

name                     old speed      new speed      delta
GobDecode-4               134MB/s ± 1%   131MB/s ± 1%  -2.32%  (p=0.000 n=23+22)
GobEncode-4               170MB/s ± 1%   157MB/s ± 1%  -7.68%  (p=0.000 n=22+22)
Gzip-4                   98.7MB/s ± 0%  96.1MB/s ± 1%  -2.68%  (p=0.000 n=23+24)
Gunzip-4                  590MB/s ± 7%   593MB/s ± 2%    ~     (p=0.466 n=23+24)
JSONEncode-4              141MB/s ± 1%   139MB/s ± 2%  -1.13%  (p=0.000 n=22+23)
JSONDecode-4             40.9MB/s ± 1%  40.3MB/s ± 0%  -1.47%  (p=0.000 n=23+23)
GoParse-4                20.1MB/s ± 1%  20.2MB/s ± 1%  +0.69%  (p=0.000 n=21+22)
RegexpMatchEasy0_32-4     435MB/s ± 1%   444MB/s ± 2%  +2.21%  (p=0.000 n=21+22)
RegexpMatchEasy0_1K-4    5.89GB/s ± 1%  5.89GB/s ± 1%    ~     (p=0.439 n=22+24)
RegexpMatchEasy1_32-4     445MB/s ± 1%   459MB/s ± 1%  +3.06%  (p=0.000 n=23+20)
RegexpMatchEasy1_1K-4    3.26GB/s ± 1%  3.32GB/s ± 1%  +1.97%  (p=0.000 n=22+23)
RegexpMatchMedium_32-4   9.40MB/s ± 1%  9.44MB/s ± 1%  +0.43%  (p=0.000 n=23+21)
RegexpMatchMedium_1K-4   29.8MB/s ± 1%  29.8MB/s ± 1%    ~     (p=0.826 n=23+22)
RegexpMatchHard_32-4     19.1MB/s ± 1%  19.1MB/s ± 7%    ~     (p=0.233 n=22+23)
RegexpMatchHard_1K-4     19.9MB/s ± 1%  20.3MB/s ± 1%  +2.03%  (p=0.000 n=22+23)
Revcomp-4                 664MB/s ± 1%   612MB/s ± 0%  -7.85%  (p=0.000 n=22+22)
Template-4               37.6MB/s ± 1%  37.7MB/s ± 1%    ~     (p=0.558 n=20+23)
[Geo mean]                134MB/s        133MB/s       -0.76%
Tue Mar 28 22:16:54 EDT 2017

Change-Id: I4a4f5c2b53d3fb85ef76c98522d3ed5cf8ae5b7e
Reviewed-on: https://go-review.googlesource.com/38732Reviewed-by: Russ Cox <rsc@golang.org>

"go env" prints Go environment information as a shell script format by
default but it's difficult for some tools (e.g. editor packages) to
interpret it.

The -json flag prints the environment in JSON format which
can be easily interpreted by a lot of tools.

$ go env -json
{
        "CC": "gcc",
        "CGO_CFLAGS": "-g -O2",
        "CGO_CPPFLAGS": "",
        "CGO_CXXFLAGS": "-g -O2",
        "CGO_ENABLED": "1",
        "CGO_FFLAGS": "-g -O2",
        "CGO_LDFLAGS": "-g -O2",
        "CXX": "g++",
        "GCCGO": "gccgo",
        "GOARCH": "amd64",
        "GOBIN": "/home/haya14busa/go/bin",
        "GOEXE": "",
        "GOGCCFLAGS": "-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build498013955=/tmp/go-build -gno-record-gcc-switches",
        "GOHOSTARCH": "amd64",
        "GOHOSTOS": "linux",
        "GOOS": "linux",
        "GOPATH": "/home/haya14busa",
        "GORACE": "",
        "GOROOT": "/home/haya14busa/src/go.googlesource.com/go",
        "GOTOOLDIR": "/home/haya14busa/src/go.googlesource.com/go/pkg/tool/linux_amd64",
        "PKG_CONFIG": "pkg-config"
}

Also, it supports arguments with -json flag.

$ go env -json GOROOT GOPATH GOBIN
{
        "GOBIN": "/home/haya14busa/go/bin",
        "GOPATH": "/home/haya14busa",
        "GOROOT": "/home/haya14busa/src/go.googlesource.com/go"
}

Fixes #12567

Change-Id: I75db3780f14a8ab8c7fa58cc3c9cc488ef7b66a1
Reviewed-on: https://go-review.googlesource.com/38757Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

gc.state.placeholder was added in 5a6e511c but never used.

Change-Id: I5a621507279d5bb1f3991b7a412d9a63039c464e
Reviewed-on: https://go-review.googlesource.com/38755Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Make byteswapreg more Go like.

Change-Id: Ibdf3603cae9cad2b3465b4c224a28a4c4c745c2e
Reviewed-on: https://go-review.googlesource.com/38615
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Use namedfield consistently.

Passes toolstash-check.

Change-Id: Ic5a3acb4bfaa1f60dd2eac94612160509e8d7f94
Reviewed-on: https://go-review.googlesource.com/38741
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Automated refactoring using gofmt.

Passes toolstash-check.

Change-Id: I8624e1c231dc736e1bb4cc800acaf629a0af91d7
Reviewed-on: https://go-review.googlesource.com/38740
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Prepared with gofmt -r.

Passes toolstash-check.

Change-Id: I8a4f7a8c365dfe464dfc5868a18c67d56af37749
Reviewed-on: https://go-review.googlesource.com/38739
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Gccgo crashed compiling a function that returned multiple zero-sized values.

Change-Id: I499112cc310e4a4f649962f4d2bc9fee95dee1b6
Reviewed-on: https://go-review.googlesource.com/38772Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This was cherry-picked to 1.8 as CL 38587, but on master issue was fixed
by CL 37661. Add still relevant part (test) and close issue, since test passes.

Fixes #19201

Change-Id: I6415792e2c465dc6d9bd6583ba1e54b107bcf5cc
Reviewed-on: https://go-review.googlesource.com/37376
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Keith Randall <khr@golang.org>

Updates #19683

Change-Id: Ic00d5a9807200791cf37553f4f802dbf27beea19
Reviewed-on: https://go-review.googlesource.com/38770
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Prior to this CL, autotmps were global to a package.
They also shared numbering with static variables.
Switch autotmp numbering to be per-function instead,
and do implicit numbering based on len(Func.Dcl).
This eliminates a dependency on a global variable
from the backend without adding to the Func struct.
While we're here, move statuniqgen closer to its
sole remaining user.

This actually improves compiler performance,
because the autotmp_* names can now be
reused across functions.

name       old alloc/op    new alloc/op    delta
Template      40.6MB ± 0%     40.1MB ± 0%  -1.38%  (p=0.000 n=10+10)
Unicode       29.9MB ± 0%     29.9MB ± 0%    ~     (p=0.912 n=10+10)
GoTypes        116MB ± 0%      114MB ± 0%  -1.53%  (p=0.000 n=10+10)
SSA            865MB ± 0%      856MB ± 0%  -1.04%  (p=0.000 n=10+10)
Flate         25.8MB ± 0%     25.4MB ± 0%  -1.36%  (p=0.000 n=10+10)
GoParser      32.2MB ± 0%     32.0MB ± 0%  -0.72%  (p=0.000 n=10+10)
Reflect       80.3MB ± 0%     79.0MB ± 0%  -1.65%  (p=0.000 n=9+10)
Tar           27.0MB ± 0%     26.7MB ± 0%  -0.86%  (p=0.000 n=10+9)
XML           42.8MB ± 0%     42.4MB ± 0%  -0.95%  (p=0.000 n=10+10)

name       old allocs/op   new allocs/op   delta
Template        398k ± 1%       396k ± 1%  -0.59%  (p=0.002 n=10+10)
Unicode         321k ± 1%       321k ± 0%    ~     (p=0.912 n=10+10)
GoTypes        1.17M ± 0%      1.16M ± 0%  -0.77%  (p=0.000 n=10+10)
SSA            7.65M ± 0%      7.62M ± 0%  -0.40%  (p=0.000 n=10+10)
Flate           240k ± 1%       238k ± 1%  -0.56%  (p=0.001 n=10+10)
GoParser        323k ± 1%       320k ± 1%  -0.65%  (p=0.002 n=10+10)
Reflect        1.01M ± 0%      1.00M ± 0%  -0.37%  (p=0.001 n=9+10)
Tar             256k ± 1%       255k ± 0%    ~     (p=0.101 n=10+8)
XML             400k ± 1%       398k ± 1%    ~     (p=0.063 n=10+10)


Change-Id: I3c23ca98129137d373106990b1a3e1507bbe0cc3
Reviewed-on: https://go-review.googlesource.com/38729
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

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.

This is a re-roll of CL 38469.

Change-Id: Ic5b4baa250618504611fc57cbf51ab01d1eddf80
Reviewed-on: https://go-review.googlesource.com/38534
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Prior to this CL, Type.Width != 0 was the mark
of a Type whose Width had been calculated.
As a result, dowidth always recalculated
the width of struct{}.
This, combined with the prohibition on calculating
the width of a FuncArgsStruct and the use of
struct{} as a function argument,
meant that there were circumstances in which
it was forbidden to call dowidth on a type.
This inhibits refactoring to call dowidth automatically,
rather than explicitly.
Instead add a helper method, Type.WidthCalculated,
and implement as Type.Align > 0.
Type.Width is not a good candidate for tracking
whether the width has been calculated;
0 is a value type width, and Width is subject to
too much magic value game-playing.

For good measure, add a test for #11354.

Change-Id: Ie9a9fb5d924e7a2010c1904ae5e38ed4a38eaeb2
Reviewed-on: https://go-review.googlesource.com/38468
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

It reduces needless allocations on compiling onepass regex.

name                                      old time/op    new time/op    delta
CompileOnepass/^(?:(?:(?:.(?:$))?))...-4    6.31µs ± 3%    6.11µs ± 3%     ~     (p=0.056 n=5+5)
CompileOnepass/^abcd$-4                     5.69µs ±12%    4.93µs ± 4%  -13.42%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a{0,})*?)$-4          7.10µs ±12%    5.82µs ± 5%  -17.95%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a+)*)$-4              5.99µs ±10%    6.07µs ±11%     ~     (p=1.000 n=5+5)
CompileOnepass/^(?:(?:a|(?:aa)))$-4         7.36µs ± 4%    7.81µs ±19%     ~     (p=0.310 n=5+5)
CompileOnepass/^(?:[^\s\S])$-4              4.71µs ± 3%    4.71µs ± 5%     ~     (p=1.000 n=5+5)
CompileOnepass/^(?:(?:(?:a*)+))$-4          6.06µs ± 2%    6.23µs ± 9%     ~     (p=0.310 n=5+5)
CompileOnepass/^[a-c]+$-4                   4.74µs ± 4%    4.64µs ± 6%     ~     (p=0.421 n=5+5)
CompileOnepass/^[a-c]*$-4                   5.17µs ± 2%    4.68µs ± 0%   -9.57%  (p=0.016 n=5+4)
CompileOnepass/^(?:a*)$-4                   5.34µs ± 3%    5.08µs ±12%     ~     (p=0.151 n=5+5)
CompileOnepass/^(?:(?:aa)|a)$-4             7.24µs ± 5%    7.33µs ±12%     ~     (p=0.841 n=5+5)
CompileOnepass/^...$-4                      5.28µs ± 3%    4.99µs ± 9%     ~     (p=0.095 n=5+5)
CompileOnepass/^(?:a|(?:aa))$-4             7.20µs ± 4%    7.24µs ±10%     ~     (p=0.841 n=5+5)
CompileOnepass/^a((b))c$-4                  7.99µs ± 3%    7.76µs ± 8%     ~     (p=0.151 n=5+5)
CompileOnepass/^a.[l-nA-Cg-j]?e$-4          8.30µs ± 5%    7.29µs ± 4%  -12.08%  (p=0.008 n=5+5)
CompileOnepass/^a((b))$-4                   7.34µs ± 4%    7.24µs ±19%     ~     (p=0.690 n=5+5)
CompileOnepass/^a(?:(b)|(c))c$-4            9.80µs ± 6%    9.49µs ±18%     ~     (p=0.151 n=5+5)
CompileOnepass/^a(?:b|c)$-4                 5.23µs ± 3%    4.80µs ±10%     ~     (p=0.056 n=5+5)
CompileOnepass/^a(?:b?|c)$-4                8.26µs ± 3%    7.30µs ± 3%  -11.62%  (p=0.008 n=5+5)
CompileOnepass/^a(?:b?|c+)$-4               9.18µs ± 2%    8.16µs ± 2%  -11.06%  (p=0.008 n=5+5)
CompileOnepass/^a(?:bc)+$-4                 6.16µs ± 3%    6.41µs ±13%     ~     (p=0.548 n=5+5)
CompileOnepass/^a(?:[bcd])+$-4              5.75µs ± 5%    5.50µs ±12%     ~     (p=0.151 n=5+5)
CompileOnepass/^a((?:[bcd])+)$-4            7.65µs ± 5%    6.93µs ± 9%     ~     (p=0.056 n=5+5)
CompileOnepass/^a(:?b|c)*d$-4               13.0µs ± 1%    12.1µs ± 2%   -6.91%  (p=0.008 n=5+5)
CompileOnepass/^.bc(d|e)*$-4                9.20µs ± 4%    8.25µs ± 3%  -10.38%  (p=0.008 n=5+5)
CompileOnepass/^loooooooooooooooooo...-4     254µs ± 2%     220µs ± 6%  -13.47%  (p=0.008 n=5+5)

name                                      old alloc/op   new alloc/op   delta
CompileOnepass/^(?:(?:(?:.(?:$))?))...-4    3.92kB ± 0%    3.41kB ± 0%  -13.06%  (p=0.008 n=5+5)
CompileOnepass/^abcd$-4                     3.20kB ± 0%    2.75kB ± 0%  -14.00%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a{0,})*?)$-4          3.85kB ± 0%    3.34kB ± 0%  -13.31%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a+)*)$-4              3.46kB ± 0%    2.95kB ± 0%  -14.78%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a|(?:aa)))$-4         4.20kB ± 0%    3.75kB ± 0%  -10.67%  (p=0.008 n=5+5)
CompileOnepass/^(?:[^\s\S])$-4              3.10kB ± 0%    2.46kB ± 0%  -20.62%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:(?:a*)+))$-4          3.64kB ± 0%    3.13kB ± 0%  -14.07%  (p=0.008 n=5+5)
CompileOnepass/^[a-c]+$-4                   3.06kB ± 0%    2.48kB ± 0%  -18.85%  (p=0.008 n=5+5)
CompileOnepass/^[a-c]*$-4                   3.10kB ± 0%    2.52kB ± 0%  -18.60%  (p=0.008 n=5+5)
CompileOnepass/^(?:a*)$-4                   3.21kB ± 0%    2.63kB ± 0%  -17.96%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:aa)|a)$-4             4.09kB ± 0%    3.64kB ± 0%  -10.96%  (p=0.008 n=5+5)
CompileOnepass/^...$-4                      3.42kB ± 0%    2.91kB ± 0%  -14.95%  (p=0.008 n=5+5)
CompileOnepass/^(?:a|(?:aa))$-4             4.09kB ± 0%    3.64kB ± 0%  -10.96%  (p=0.008 n=5+5)
CompileOnepass/^a((b))c$-4                  5.67kB ± 0%    4.39kB ± 0%  -22.59%  (p=0.008 n=5+5)
CompileOnepass/^a.[l-nA-Cg-j]?e$-4          5.73kB ± 0%    4.32kB ± 0%  -24.58%  (p=0.008 n=5+5)
CompileOnepass/^a((b))$-4                   5.41kB ± 0%    4.06kB ± 0%  -24.85%  (p=0.008 n=5+5)
CompileOnepass/^a(?:(b)|(c))c$-4            6.40kB ± 0%    5.31kB ± 0%  -17.00%  (p=0.008 n=5+5)
CompileOnepass/^a(?:b|c)$-4                 3.46kB ± 0%    2.88kB ± 0%  -16.67%  (p=0.008 n=5+5)
CompileOnepass/^a(?:b?|c)$-4                5.77kB ± 0%    4.36kB ± 0%  -24.41%  (p=0.008 n=5+5)
CompileOnepass/^a(?:b?|c+)$-4               5.94kB ± 0%    4.59kB ± 0%  -22.64%  (p=0.008 n=5+5)
CompileOnepass/^a(?:bc)+$-4                 3.60kB ± 0%    3.15kB ± 0%  -12.44%  (p=0.008 n=5+5)
CompileOnepass/^a(?:[bcd])+$-4              3.46kB ± 0%    2.94kB ± 0%  -14.81%  (p=0.008 n=5+5)
CompileOnepass/^a((?:[bcd])+)$-4            5.50kB ± 0%    4.09kB ± 0%  -25.62%  (p=0.008 n=5+5)
CompileOnepass/^a(:?b|c)*d$-4               7.24kB ± 0%    6.15kB ± 0%  -15.03%  (p=0.008 n=5+5)
CompileOnepass/^.bc(d|e)*$-4                5.75kB ± 0%    4.47kB ± 0%  -22.25%  (p=0.008 n=5+5)
CompileOnepass/^loooooooooooooooooo...-4     225kB ± 0%     135kB ± 0%  -39.99%  (p=0.008 n=5+5)

name                                      old allocs/op  new allocs/op  delta
CompileOnepass/^(?:(?:(?:.(?:$))?))...-4      52.0 ± 0%      49.0 ± 0%   -5.77%  (p=0.008 n=5+5)
CompileOnepass/^abcd$-4                       44.0 ± 0%      41.0 ± 0%   -6.82%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a{0,})*?)$-4            52.0 ± 0%      49.0 ± 0%   -5.77%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a+)*)$-4                47.0 ± 0%      44.0 ± 0%   -6.38%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:a|(?:aa)))$-4           57.0 ± 0%      54.0 ± 0%   -5.26%  (p=0.008 n=5+5)
CompileOnepass/^(?:[^\s\S])$-4                36.0 ± 0%      33.0 ± 0%   -8.33%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:(?:a*)+))$-4            49.0 ± 0%      46.0 ± 0%   -6.12%  (p=0.008 n=5+5)
CompileOnepass/^[a-c]+$-4                     39.0 ± 0%      36.0 ± 0%   -7.69%  (p=0.008 n=5+5)
CompileOnepass/^[a-c]*$-4                     44.0 ± 0%      41.0 ± 0%   -6.82%  (p=0.008 n=5+5)
CompileOnepass/^(?:a*)$-4                     45.0 ± 0%      42.0 ± 0%   -6.67%  (p=0.008 n=5+5)
CompileOnepass/^(?:(?:aa)|a)$-4               56.0 ± 0%      53.0 ± 0%   -5.36%  (p=0.008 n=5+5)
CompileOnepass/^...$-4                        46.0 ± 0%      43.0 ± 0%   -6.52%  (p=0.008 n=5+5)
CompileOnepass/^(?:a|(?:aa))$-4               56.0 ± 0%      53.0 ± 0%   -5.36%  (p=0.008 n=5+5)
CompileOnepass/^a((b))c$-4                    57.0 ± 0%      53.0 ± 0%   -7.02%  (p=0.008 n=5+5)
CompileOnepass/^a.[l-nA-Cg-j]?e$-4            62.0 ± 0%      58.0 ± 0%   -6.45%  (p=0.008 n=5+5)
CompileOnepass/^a((b))$-4                     51.0 ± 0%      47.0 ± 0%   -7.84%  (p=0.008 n=5+5)
CompileOnepass/^a(?:(b)|(c))c$-4              69.0 ± 0%      65.0 ± 0%   -5.80%  (p=0.008 n=5+5)
CompileOnepass/^a(?:b|c)$-4                   43.0 ± 0%      40.0 ± 0%   -6.98%  (p=0.008 n=5+5)
CompileOnepass/^a(?:b?|c)$-4                  61.0 ± 0%      57.0 ± 0%   -6.56%  (p=0.008 n=5+5)
CompileOnepass/^a(?:b?|c+)$-4                 67.0 ± 0%      63.0 ± 0%   -5.97%  (p=0.008 n=5+5)
CompileOnepass/^a(?:bc)+$-4                   49.0 ± 0%      46.0 ± 0%   -6.12%  (p=0.008 n=5+5)
CompileOnepass/^a(?:[bcd])+$-4                46.0 ± 0%      43.0 ± 0%   -6.52%  (p=0.008 n=5+5)
CompileOnepass/^a((?:[bcd])+)$-4              53.0 ± 0%      49.0 ± 0%   -7.55%  (p=0.008 n=5+5)
CompileOnepass/^a(:?b|c)*d$-4                  109 ± 0%       105 ± 0%   -3.67%  (p=0.008 n=5+5)
CompileOnepass/^.bc(d|e)*$-4                  66.0 ± 0%      62.0 ± 0%   -6.06%  (p=0.008 n=5+5)
CompileOnepass/^loooooooooooooooooo...-4     1.10k ± 0%     1.09k ± 0%   -0.91%  (p=0.008 n=5+5)

Fixes #19735

Change-Id: Ic68503aaa08e42fafcf7e11cf1f584d674f5ea7b
Reviewed-on: https://go-review.googlesource.com/38750Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

It is explicitly assigned in each of the
assemblers as needed.
I plan to remove Cursym entirely eventually,
but this is a helpful intermediate step.

Passes toolstash-check -all.

Updates #15756

Change-Id: Id7ddefae2def439af44d03053886ca8cc935731f
Reviewed-on: https://go-review.googlesource.com/38727
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

It is insufficiently canonical;
see the discussion at issue 19719.

Fixes #19719

Change-Id: I0559ff3b1b39d7bc4b446d104f36fdf8ce3da50e
Reviewed-on: https://go-review.googlesource.com/38722
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

This eliminates references to lineno and
other globals from ssa conversion.

Passes toolstash-check.

Updates #15756

Change-Id: I9792074fab0036b42f454b79139d0b27db913fb5
Reviewed-on: https://go-review.googlesource.com/38721
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Fixes: #18070
Also added a test in: cmd/asm/internal/asm/testdata/arm64.s

Change-Id: Icc43ff7383cc06b8eaccabd9ff0aefa61c4ecb88
Reviewed-on: https://go-review.googlesource.com/33595
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Remove the global obj.Link.Curp.

In asmz.go, replace the only use by passing it as an argument.
In asm0.go and asm9.go, it was written but never read.
In asm5.go and asm7.go, thread it through as an argument.

Passes toolstash-check -all.

Updates #15756

Change-Id: I1a0faa89e768820f35d73a8b37ec8088d78d15f7
Reviewed-on: https://go-review.googlesource.com/38715
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fold the printing of the offending instruction
into the neighboring Diag call, if it is not
already present.

Change-Id: I310f1479e16a4d2a24ff3c2f7e2c60e5e2015c1b
Reviewed-on: https://go-review.googlesource.com/38714
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The result from CFBundleCopyResourceURL is owned by the caller. This
CL adds the necessary CFRelease to release it after use.

Fixes #19722

Change-Id: I7afe22ef241d21922a7f5cef6498017e6269a5c3
Reviewed-on: https://go-review.googlesource.com/38639
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

The global encbuf helped avoid allocations.
It is incompatible with a concurrent backend.
To avoid a performance regression while removing it,
introduce two optimizations.
First, re-use a buffer in dwarf.PutFunc.
Second, avoid a buffer entirely when the int
being encoded fits in seven bits, which is about 75%
of the time.

Passes toolstash-check.

Updates #15756


name       old alloc/op    new alloc/op    delta
Template      40.6MB ± 0%     40.6MB ± 0%  -0.08%  (p=0.001 n=8+9)
Unicode       29.9MB ± 0%     29.9MB ± 0%    ~     (p=0.068 n=8+10)
GoTypes        116MB ± 0%      116MB ± 0%  +0.05%  (p=0.043 n=10+9)
SSA            864MB ± 0%      864MB ± 0%  +0.01%  (p=0.010 n=10+9)
Flate         25.8MB ± 0%     25.8MB ± 0%    ~     (p=0.353 n=10+10)
GoParser      32.2MB ± 0%     32.2MB ± 0%    ~     (p=0.353 n=10+10)
Reflect       80.2MB ± 0%     80.2MB ± 0%    ~     (p=0.165 n=10+10)
Tar           27.0MB ± 0%     26.9MB ± 0%    ~     (p=0.143 n=10+10)
XML           42.8MB ± 0%     42.8MB ± 0%    ~     (p=0.400 n=10+9)

name       old allocs/op   new allocs/op   delta
Template        398k ± 0%       397k ± 0%  -0.20%  (p=0.002 n=8+9)
Unicode         320k ± 0%       321k ± 1%    ~     (p=0.122 n=8+10)
GoTypes        1.16M ± 0%      1.17M ± 0%    ~     (p=0.053 n=10+9)
SSA            7.65M ± 0%      7.65M ± 0%    ~     (p=0.122 n=10+8)
Flate           240k ± 1%       240k ± 1%    ~     (p=0.243 n=10+9)
GoParser        322k ± 1%       322k ± 1%    ~     (p=0.481 n=10+10)
Reflect        1.00M ± 0%      1.00M ± 0%    ~     (p=0.211 n=9+10)
Tar             256k ± 0%       255k ± 1%    ~     (p=0.052 n=10+10)
XML             400k ± 1%       400k ± 0%    ~     (p=0.631 n=10+10)


Change-Id: Ia39d9de09232fdbfc9c9cec14587bbf6939c9492
Reviewed-on: https://go-review.googlesource.com/38713
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

If the user created an httptest.Server directly without using a
constructor it won't have the new unexported 'client' field. So don't
assume it's non-nil.

Fixes #19729

Change-Id: Ie92e5da66cf4e7fb8d95f3ad0f4e3987d3ae8b77
Reviewed-on: https://go-review.googlesource.com/38710
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Kevin Burke <kev@inburke.com>

We reused the old C stack check mechanism for the implementation of
//go:systemstack, so when we execute a //go:systemstack function on a
user stack, the system fails by calling morestackc. However,
morestackc's message still talks about "executing C code".

Fix morestackc's message to reflect its modern usage.

Change-Id: I7e70e7980eab761c0520f675d3ce89486496030f
Reviewed-on: https://go-review.googlesource.com/38572
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

On Android, the thread local offset is found by looping through memory
starting at the TLS base address. The search is limited to
PTHREAD_KEYS_MAX, but issue 19472 made it clear that in some cases, the
slot is located further from the TLS base.

The limit is merely a sanity check in case our assumptions about the
thread-local storage layout are wrong, so this CL raises it to 384, which
is enough for the test case in issue 19472.

Fixes #19472

Change-Id: I89d1db3e9739d3a7fff5548ae487a7483c0a278a
Reviewed-on: https://go-review.googlesource.com/38636
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The proto_test tests are failing on NetBSD:

https://build.golang.org/log/a3a577144ac48c6ef8e384ce6a700ad30549fb78

the failures seem similar to previous failures on Android:

https://build.golang.org/log/b5786e0cd6d5941dc37b6a50be5172f6b99e22f0

The Android failures where fixed by CL 37896. This CL is an attempt
to fix the NetBSD failures with a similar fix.

Change-Id: I3834afa5b32303ca226e6a31f0f321f66fef9a3f
Reviewed-on: https://go-review.googlesource.com/38637Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Follow-up to CL 38668.

Passes toolstash-check -all.

Change-Id: I78a62509c610b5184b5e7ef2c4aa146fc8038840
Reviewed-on: https://go-review.googlesource.com/38670
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

Follow-up to CL 38446.

Passes toolstash-check -all.

Change-Id: I04cadc058cbaa5f396136502c574e5a395a33276
Reviewed-on: https://go-review.googlesource.com/38669
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

These fields are used to encode a single instruction.
Add them to AsmBuf, which is also per-instruction,
and which is not global.

Updates #15756

Change-Id: I0e5ea22ffa641b07291e27de6e2ff23b6dc534bd
Reviewed-on: https://go-review.googlesource.com/38668
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>