Unless you go back and read the hash package documentation, it's
not clear that all the hash packages implement marshaling and
unmarshaling. Document the behaviour specifically in each package
that implements it as it this is hidden behaviour and easy to miss.

Change-Id: Id9d3508909362f1a3e53872d0319298359e50a94
Reviewed-on: https://go-review.googlesource.com/77251Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>

If the Linux kernel was built with CONFIG_OPTIMIZE_INLINING=n and was
built with hardening options turned on, GCC will insert a stack probe
in the VDSO function that requires a full page of stack space.
The stack probe can corrupt memory if another thread is using it.
Avoid sporadic crashes by calling the VDSO on the g0 or gsignal stack.

While we're at it, align the stack as C code expects. We've been
getting away with a misaligned stack, but it's possible that the VDSO
code will change in the future to break that assumption.

Benchmarks show a 11% hit on time.Now, but it's only 6ns.

name                      old time/op  new time/op  delta
AfterFunc-12              1.66ms ± 0%  1.66ms ± 1%     ~     (p=0.905 n=9+10)
After-12                  1.90ms ± 6%  1.86ms ± 0%   -2.05%  (p=0.012 n=10+8)
Stop-12                    113µs ± 3%   115µs ± 2%   +1.60%  (p=0.017 n=9+10)
SimultaneousAfterFunc-12   145µs ± 1%   144µs ± 0%   -0.68%  (p=0.002 n=10+8)
StartStop-12              39.5µs ± 3%  40.4µs ± 5%   +2.19%  (p=0.023 n=10+10)
Reset-12                  10.2µs ± 0%  10.4µs ± 0%   +2.45%  (p=0.000 n=10+9)
Sleep-12                   190µs ± 1%   190µs ± 1%     ~     (p=0.971 n=10+10)
Ticker-12                 4.68ms ± 2%  4.64ms ± 2%   -0.83%  (p=0.043 n=9+10)
Now-12                    48.4ns ±11%  54.0ns ±11%  +11.42%  (p=0.017 n=10+10)
NowUnixNano-12            48.5ns ±13%  56.9ns ± 8%  +17.30%  (p=0.000 n=10+10)
Format-12                  489ns ±11%   504ns ± 6%     ~     (p=0.289 n=10+10)
FormatNow-12               436ns ±23%   480ns ±13%  +10.25%  (p=0.026 n=9+10)
MarshalJSON-12             656ns ±14%   587ns ±24%     ~     (p=0.063 n=10+10)
MarshalText-12             647ns ± 7%   638ns ± 9%     ~     (p=0.516 n=10+10)
Parse-12                   348ns ± 8%   328ns ± 9%   -5.66%  (p=0.030 n=10+10)
ParseDuration-12           136ns ± 9%   140ns ±11%     ~     (p=0.425 n=10+10)
Hour-12                   14.8ns ± 6%  15.6ns ±11%     ~     (p=0.085 n=10+10)
Second-12                 14.0ns ± 6%  14.3ns ±12%     ~     (p=0.443 n=10+10)
Year-12                   32.4ns ±11%  33.4ns ± 6%     ~     (p=0.492 n=10+10)
Day-12                    41.5ns ± 9%  42.3ns ±12%     ~     (p=0.239 n=10+10)

Fixes #20427

Change-Id: Ia395cbb863215f4499b8e7ef95f4b99f51090911
Reviewed-on: https://go-review.googlesource.com/76990Reviewed-by: Austin Clements <austin@google.com>

I verified this change on a corpus of > 200 GB of emails since the mid-90s. With
this change, more addresses parse than before, and anything which parsed before
still parses.

In said corpus, I came across the edge case of comments preceding an
addr-spec (with angle brackets!), e.g. “(John Doe) <john@example.com>”, which
does not satisfy the conditions to be treated as a fallback, as per my reading
of RFC2822.

This change does not parse quoted-strings within comments (a corresponding TODO
is in the code), but I have not seen that in the wild.

Fixes #22670

Change-Id: I526fcf7c6390aa1c219fdec1852f26c514506f76
Reviewed-on: https://go-review.googlesource.com/77474Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

GDB 7.5 recognizes DWARF4 by default.

GDB 7.5 release note does not explicitly mention DWARF4 support
but according to GCC 4.8 release note
 https://gcc.gnu.org/gcc-4.8/changes.html

 "DWARF4 is now the default when generating DWARF debug
 information. ...
 GDB 7.5, Valgrind 3.8.0 and elfutils 0.154 debug information
 consumers support DWARF4 by default."

Change-Id: I56b011c7c38fbc103bbd366ceaea3b709c66ab7f
Reviewed-on: https://go-review.googlesource.com/77570Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>

change hash/crc32 package to use cpu package instead of using
runtime internal variables to check crc32 instruction

Change-Id: I8f88d2351bde8ed4e256f9adf822a08b9a00f532
Reviewed-on: https://go-review.googlesource.com/76490Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

I submitted two CLs which broke the build. Add temporary placeholder
with false bools to fix the build and restore old behavior.

Updates golang/go#22718 (details of why it broke)

Change-Id: I1f30624e14f631a95f4eff5aae462f1091f723a2
Reviewed-on: https://go-review.googlesource.com/77590Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Optimize with ARMv8 SHA256 instructions.
Result (Cortex-A72)

name           old time/op    new time/op      delta
Hash8Bytes-64    1.54µs ± 1%      0.61µs ± 9%    -60.67%  (p=0.008 n=5+5)
Hash1K-64        17.2µs ± 1%       1.4µs ± 2%    -91.91%  (p=0.008 n=5+5)
Hash8K-64         127µs ± 0%         7µs ± 1%    -94.42%  (p=0.008 n=5+5)

name           old speed      new speed        delta
Hash8Bytes-64  5.20MB/s ± 1%   13.23MB/s ±10%   +154.58%  (p=0.008 n=5+5)
Hash1K-64      59.4MB/s ± 1%   735.1MB/s ± 2%  +1136.96%  (p=0.008 n=5+5)
Hash8K-64      64.5MB/s ± 0%  1156.3MB/s ± 1%  +1692.75%  (p=0.008 n=5+5)

Change-Id: I47eca6471b75cd07cb0c77477053a07d0de7494f
Reviewed-on: https://go-review.googlesource.com/61570Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Optimize with ARMv8 SHA1 instructions.
Results (Cortex-A72)

name             old time/op    new time/op     delta
Hash8Bytes-64      1.06µs ± 4%     0.56µs ± 4%   -47.19%  (p=0.008 n=5+5)
Hash320Bytes-64    3.92µs ± 1%     0.82µs ± 2%   -79.07%  (p=0.008 n=5+5)
Hash1K-64          10.2µs ± 2%      1.5µs ± 2%   -85.71%  (p=0.008 n=5+5)
Hash8K-64          73.9µs ± 1%      7.6µs ± 1%   -89.66%  (p=0.008 n=5+5)

name             old speed      new speed       delta
Hash8Bytes-64    7.55MB/s ± 4%  14.29MB/s ± 4%   +89.27%  (p=0.008 n=5+5)
Hash320Bytes-64  81.6MB/s ± 1%  390.0MB/s ± 2%  +377.64%  (p=0.008 n=5+5)
Hash1K-64         100MB/s ± 2%    701MB/s ± 2%  +599.65%  (p=0.008 n=5+5)
Hash8K-64         111MB/s ± 1%   1072MB/s ± 1%  +867.44%  (p=0.008 n=5+5)

Change-Id: I84397f980db9518f4150ac4c5ffa2c5a97a34444
Reviewed-on: https://go-review.googlesource.com/61550Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

A clarifying comment was added to indicate that overflow of a
single Word is not possible in the single digit calculation.
Lehmer's paper includes a proof of the bounds on the size of the
cosequences (u0, u1, u2, v0, v1, v2).

Change-Id: I98127a07aa8f8fe44814b74b2bc6ff720805194b
Reviewed-on: https://go-review.googlesource.com/77451Reviewed-by: Robert Griesemer <gri@golang.org>

Previously when RoundTrip returned a non-nil error, the proxy returned a
StatusBadGateway error, instead of first calling ModifyResponse. This
commit first calls ModifyResponse, whether or not the error returned
from RoundTrip is nil.

Also closes response body when ModifyResponse returns an error. See #22658.

Fixes #21255

Change-Id: I5b5bf23a69ae5608f87d4ece756a1b4985ccaa9c
Reviewed-on: https://go-review.googlesource.com/54030Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

In the doc for QueryUnescape and PathUnescape, clarify that by 0xAB we
means a substring with any two valid hexadecimal digits.

Fixes #18642

Change-Id: Ib65b130995ae5fcf07e25ee0fcc41fad520c5662
Reviewed-on: https://go-review.googlesource.com/77050Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #22703

The fix was already done by Cherry for defer/go of an interface call (CL 23820).
We just need to do it everywhere.

Change-Id: I0115d22e443931fe1bcce44c93c4d0770b5fd268
Reviewed-on: https://go-review.googlesource.com/77450
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Use maxConsecutiveEmptyReads const instead of hardcoded
100 in scan.go too.

Change-Id: I993f353a3748f0d6bdefab38bf5cb224eea8a969
Reviewed-on: https://go-review.googlesource.com/46915Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Just copy some code to make TestWindowsStackMemory build
when CGO_ENABLED is set to 0.

Fixes #22680

Change-Id: I63f9b409a3a97b7718f5d37837ab706d8ed92e81
Reviewed-on: https://go-review.googlesource.com/77430Reviewed-by: Chris Hines <chris.cs.guy@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #19579

Change-Id: Id99ca6de94d8d895dfaed1ed507e9d36c7f60670
Reviewed-on: https://go-review.googlesource.com/48869Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Before terminating the connectionResetter goroutine the connection
pool processes all of the connections on the channel to unlock the
driverConn instances so everthing can shutdown cleanly. However
the channel was never closed so the goroutine hangs on the range.
Close the channel prior to ranging over it. Also prevent additional
connections from being sent to the resetter after the connection
pool has been closed.

Fixes #22699

Change-Id: I440d2b13cbedec2e04621557f5bd0b1526933dd7
Reviewed-on: https://go-review.googlesource.com/77390
Run-TryBot: Daniel Theophanes <kardianos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The cryptographic checksums operate in blocks of 64 or 128 bytes,
which means that the last 128 bytes or so of the input may be encoded
in its original (plaintext) form as part of the state.
Document this so users do not falsely assume that the encoded state
carries no reversible information about the input.

Change-Id: I823dbb87867bf0a77aa20f6ed7a615dbedab3715
Reviewed-on: https://go-review.googlesource.com/77372Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

CL 45412 started hiding autogenerated wrapper functions from call
stacks so that call stack semantics better matched language semantics.
This is based on the theory that the wrapper function will call the
"real" function and all the programmer knows about is the real
function.

However, this theory breaks down in two cases:

1. If the wrapper is at the top of the stack, then it didn't call
   anything. This can happen, for example, if the "stack" was actually
   synthesized by the user.

2. If the wrapper panics, for example by calling panicwrap or by
   dereferencing a nil pointer, then it didn't call the wrapped
   function and the user needs to see what panicked, even if we can't
   attribute it nicely.

This commit modifies the traceback logic to include the wrapper
function in both of these cases.

Fixes #22231.

Change-Id: I6e4339a652f73038bd8331884320f0b8edd86eb1
Reviewed-on: https://go-review.googlesource.com/76770
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

The Go compiler assumes that pointers escape when passed into assembly
functions. To override this behavior we can annotate assembly functions
with go:noescape, telling the compiler that we know pointers do not
escape from it.

By annotating the assembly functions in the s390x P256 code in this way
we enable more variables to be allocated on the stack rather than
the heap, reducing the number of heap allocations required to execute
this code:

name        old alloc/op   new alloc/op   delta
SignP256      3.66kB ± 0%    2.64kB ± 0%  -27.95%  (p=0.008 n=5+5)
VerifyP256    4.46kB ± 0%    1.23kB ± 0%  -72.40%  (p=0.008 n=5+5)

name        old allocs/op  new allocs/op  delta
SignP256        40.0 ± 0%      31.0 ± 0%  -22.50%  (p=0.008 n=5+5)
VerifyP256      41.0 ± 0%      24.0 ± 0%  -41.46%  (p=0.008 n=5+5)

Change-Id: Id526c30c9b04b2ad79a55d76cab0e30cc8d60402
Reviewed-on: https://go-review.googlesource.com/66230
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Split typecheckrange into two, separating the bigger chunk of code that
takes care of the range expression. It had to sometimes exit early,
which was done via a goto in the larger func. This lets us simplify many
declarations and the flow of the code. While at it, also replace the
toomany int with a bool.

In the case of walkselect, split it into two funcs too since using a
defer for all the trailing work would be a bit much. It also lets us
simplify the declarations and the flow of the code, since now
walkselectcases has a narrower scope and straightforward signature.

Also replace the gotos in typecheckaste with a lineno defer.

Passes toolstash -cmp on std cmd.

Change-Id: Iacfaa0a34c987c44f180a792c473558785cf6823
Reviewed-on: https://go-review.googlesource.com/72374
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

If people are interested in contributing to Go, but not sure what
change they'd like to make just yet, we can point them to the scratch
repo, so they can go through the process of submitting and merging
something now, and make more useful contributions later.

My evidence that sending people to the scratch repo would encourage
future contributions is that a number of people who went through the
workshop at Gophercon have continued to send CL's after submitting to
the scratch repo, even though I doubt they planned to before going
through the workshop.

Change-Id: Ieb48415773c0ee7dc400f8bf6f57f752eca8eeb5
Reviewed-on: https://go-review.googlesource.com/49970Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This test fails on 1.9.2, but is ok on tip.
CL 77331 has both the 1.9.2 fix and this test, and is on the 1.9 release branch.
This CL is just the test, and is on HEAD.  The buggy code doesn't exist on tip.

Update #22683

Change-Id: I04a24bd6c2d3068e18ca81da3347e2c1366f4447
Reviewed-on: https://go-review.googlesource.com/77332
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ie64eba5b57b609a343ddb381fe83c01f172c0bf4
Reviewed-on: https://go-review.googlesource.com/60890Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

CL 60410 fixes a bug in reflect that allows assignments to an embedded
field of a pointer to an unexported struct type.
This breaks the json package because unmarshal is now unable to assign
a newly allocated struct to such fields.

In order to be consistent in the behavior for marshal and unmarshal,
this CL changes both marshal and unmarshal to always ignore
embedded pointers to unexported structs.

Fixes #21357

Change-Id: If62ea11155555e61115ebb9cfa5305caf101bde5
Reviewed-on: https://go-review.googlesource.com/76851
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #22608.

Change-Id: Id85eb86b0b262156646e55f102fe888b345b20cf
Reviewed-on: https://go-review.googlesource.com/77230
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

GitHub has defined a set of standard meta files to include with projects
hosted on GitHub. According to the GitHub Insights Community page for
go project the only one missing is the code of conduct.

Go has a code of conduct on it's website and we should link to it in the
prescribed `.github/CODE_OF_CONDUCT.md` so that people can find it in
the standard location on GitHub. This would be consistent with the
contribution guidelines that are linked to in `.github/CONTRIBUTING.md`.

Ref: https://help.github.com/articles/adding-a-code-of-conduct-to-your-project/

Fixes #22685

Change-Id: Ie89aa39d3df741d7d6ed2dba5c8ba3d0e0dbf618
Reviewed-on: https://go-review.googlesource.com/77231Reviewed-by: Gabriel Aszalos <gabriel.aszalos@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Also, with this change, error locations don't print absolute positions
in [] brackets following positions relative to line directives. To get
the absolute positions as well, specify the -L flag.

Fixes #22660.

Change-Id: I9ecfa254f053defba9c802222874155fa12fee2c
Reviewed-on: https://go-review.googlesource.com/77090Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

cmd/cover rewrites Go source code to add coverage annotations.
The approach to date has been to parse the code to AST, analyze it,
rewrite the AST, and print it back out. This approach fails to preserve
line numbers in the original code and has a very difficult time with
comments, because go/printer does as well.

This CL changes cmd/cover to decide what to modify based on the
AST but to apply the modifications as purely textual substitutions.
In this way, cmd/cover can be sure it never adds or removes a newline
character, nor a comment, so all line numbers and comments are
preserved.

This also allows us to emit a single //line comment at the beginning
of the translated file and have the compiler report errors with
correct line numbers in the original file.

Fixes #6329.
Fixes #15757.

Change-Id: Ia95f6f894bb498e80d1f91fde56cd4a8009d7f9b
Reviewed-on: https://go-review.googlesource.com/77150Reviewed-by: Ian Lance Taylor <iant@golang.org>

Per discussion with David Chase, need to check GOSSAHASH$n
for increasing n until one is missing. Also if GSHS_LOGFILE is set,
the compiler writes to that file, so arrange never to cache in that case.

Change-Id: I3931b4e296251b99abab9bbbbbdcf94ae8c1e2a6
Reviewed-on: https://go-review.googlesource.com/77111Reviewed-by: David Chase <drchase@google.com>

It's nice that

	go build -gcflags=-m errors
	go build -gcflags=-m errors

uses the cache for the second command.

Even nicer is to make the second command
print the same output as the first command.

Fixes #22587.

Change-Id: I64350839f01c86c9a095d9d22f6924cd7a0b9105
Reviewed-on: https://go-review.googlesource.com/77110Reviewed-by: Ian Lance Taylor <iant@golang.org>

Another one that is possible thanks to the new -trimprefix stringer
flag.

The only subtle difference is that, in the previous version, some values
such as TUNSAFEPTR were stringified as "TUNSAFEPTR" instead of
"UNSAFEPTR". The new String method is always consistent in removing the
"T" prefix.

Passes toolstash -cmp on std cmd.

Change-Id: I68407f391795403dfcbbfa68c813018c0235bbb5
Reviewed-on: https://go-review.googlesource.com/77250
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Marvin Stenger <marvin.stenger94@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>

Since the slice of names is almost exactly the same as what stringer is
already generating for us.

Passes toolstash -cmp on std cmd.

Change-Id: I3f1e95efc690c0108236689e721627f00f79a461
Reviewed-on: https://go-review.googlesource.com/77190
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

This allows better precision and (the motivation) empty strings to
be handled correctly. With that in place tests for the behaviour of
empty name constraints can be added.

Also fixes a compatibility issue with NSS. See #22616.

Fixes #22616

Change-Id: I5139439bb58435d5f769828a4eebf8bed2d858e8
Reviewed-on: https://go-review.googlesource.com/74271Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #22658

Change-Id: I00e2b007d77b6f54798f7755d0b08e4fea824392
Reviewed-on: https://go-review.googlesource.com/77170Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

CL 76873 added TestGoTestJSON. However, this test
is only succeeding on SMP machines.

This change skips TestGoTestJSON on uniprocessor machines.

Fixes #22665.

Change-Id: I3989d3331fb71193a25a3f0bbb84ff3e1b730890
Reviewed-on: https://go-review.googlesource.com/77130Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Sometimes getmac lists many interfaces for the same MAC address,
while Interfaces returns only single name for that address. Adjust
the test to ignore the names that are not returned by the Interfaces.

Fixes #21027

Change-Id: I08d98746a7c669f2d730dba2da36e07451a6f405
Reviewed-on: https://go-review.googlesource.com/59411Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>

Fixes #22093
Fixes #19988

Change-Id: Ibd8ec89e091fd527f363999e484676931d7aa6e2
Reviewed-on: https://go-review.googlesource.com/67450Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Added in CL 76873 but forgot to add the flag docs.

Change-Id: I448f85cc8cf51399c0d799691226b94f88f327da
Reviewed-on: https://go-review.googlesource.com/77030
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Caleb Spare <cespare@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

If you run

	go test -coverpkg=all fmt

one possible interpretation is that you want coverage for all the
packages involved in the fmt test, not all the packages in the world.
Because coverpkg was previously defined as a list of packages
to be loaded, however, it meant all packages in the world.

Now that the go command has a concept of package notation
being used as a matching filter instead of a direct enumeration,
apply that to -coverpkg, so that -coverpkg=all now has the
more useful filter interpretation.

Fixes #10271.
Fixes #21283.

Change-Id: Iddb77b21ba286d3dd65b62507af27e244865072d
Reviewed-on: https://go-review.googlesource.com/76876
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

It's easy to merge the coverage profiles from the
multiple executed tests, so do that.

Also ensures that at least an empty coverage profile
is always written.

Fixes #6909.
Fixes #18909.

Change-Id: I28b88e1fb0fb773c8f57e956b18904dc388cdd82
Reviewed-on: https://go-review.googlesource.com/76875
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>