This is the detection code. It works well enough that I know of
a handful of missing write barriers. However, those are subtle
enough that I'll address them in separate followup CLs.

GODEBUG=wbshadow=1 checks for a write that bypassed the
write barrier at the next write barrier of the same word.
If a bug can be detected in this mode it is typically easy to
understand, since the crash says quite clearly what kind of
word has missed a write barrier.

GODEBUG=wbshadow=2 adds a check of the write barrier
shadow copy during garbage collection. Bugs detected at
garbage collection can be difficult to understand, because
there is no context for what the found word means.
Typically you have to reproduce the problem with allocfreetrace=1
in order to understand the type of the badly updated word.

Change-Id: If863837308e7c50d96b5bdc7d65af4969bf53a6e
Reviewed-on: https://go-review.googlesource.com/2061Reviewed-by: Austin Clements <austin@google.com>

When constants were declared using unexported constants,
the type information was lost when those constants were filtered out.
This CL propagates the type information of unexported constants
so that it is available for display.

This is a follow-up to CL 144110044, which fixed this problem
specifically for _ constants.

Updates #5397.

Change-Id: I3f0c767a4007d88169a5634ab2870deea4e6a740
Reviewed-on: https://go-review.googlesource.com/2091Reviewed-by: Robert Griesemer <gri@golang.org>

Fixes #9509

Change-Id: I3b86745d38e09093fe2f4b918d774bd6608727d7
Reviewed-on: https://go-review.googlesource.com/2313Reviewed-by: Robert Griesemer <gri@golang.org>

Noticed while investigating the speed of the runtime tests, as part
of debugging while Plan 9's runtime tests are timing out on GCE.

Change-Id: I95f5a3d967a0b45ec1ebf10067e193f51db84e26
Reviewed-on: https://go-review.googlesource.com/2283Reviewed-by: Ian Lance Taylor <iant@golang.org>

The existing go code document did not link to the GOPATH documentation.
This will link to it, in hopes of making it more discoverable.

Change-Id: Ie4ded2fdce08f412e4acbcc93acdd76f5791b84a
Reviewed-on: https://go-review.googlesource.com/2265Reviewed-by: Andrew Gerrand <adg@golang.org>

Change-Id: Ic6bc4af7bcc89b2881b2b9e7290aeb6fd54804e2
Reviewed-on: https://go-review.googlesource.com/2239Reviewed-by: Ian Lance Taylor <iant@golang.org>

This reverts commit ab0535ae.

I think it will remain useful to distinguish code that must
run on a system stack from code that can run on either stack,
even if that distinction is no
longer based on the implementation language.

That is, I expect to add a //go:systemstack comment that,
in terms of the old implementation, tells the compiler,
to pretend this function was written in C.

Change-Id: I33d2ebb2f99ae12496484c6ec8ed07233d693275
Reviewed-on: https://go-review.googlesource.com/2275Reviewed-by: Russ Cox <rsc@golang.org>

Fixes #9504.

Change-Id: I148f407ace3d1b4db3f19fbb8561d1ee6c4c13b3
Reviewed-on: https://go-review.googlesource.com/2273Reviewed-by: Rob Pike <r@golang.org>

Change-Id: Ida3b431a06527f6cd604ab4af5ce517959c8619b
Reviewed-on: https://go-review.googlesource.com/2306Reviewed-by: Dave Cheney <dave@cheney.net>

Change-Id: Ie47c6460c1749aef3cf6d7c6ba44d43305d7ca7b
Reviewed-on: https://go-review.googlesource.com/2305Reviewed-by: Minux Ma <minux@golang.org>

This CL splits the (ever growing) list of ca cert locations by major unix
platforms (darwin, windows and plan9 are already handled seperately).
Although it is clear the unix variants cannot manage to agree on some standard
locations, we can avoid to some extent an artificial ranking of priority
amongst the supported GOOSs.

* Split certFiles definition by GOOS
* Include NetBSD ca cert location

Fixes #9285

Change-Id: I6df2a3fddf3866e71033e01fce43c31e51b48a9e
Reviewed-on: https://go-review.googlesource.com/2208Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>

This ensures that changing an image.YCbCr's Y values can't change its
chroma values, even after re-slicing up to capacity.

Change-Id: Icb626561522e336a3220e10f456c95330ae7db9e
Reviewed-on: https://go-review.googlesource.com/2209Reviewed-by: Rob Pike <r@golang.org>

Fixes #9448.

Change-Id: I8e1d676688d9e9b2fa3519ebc530905f574a1b3e
Reviewed-on: https://go-review.googlesource.com/2088Reviewed-by: Rob Pike <r@golang.org>

Change-Id: I7b65cf3b67bef8950115066d6d12b25cd0a5edfc
Reviewed-on: https://go-review.googlesource.com/2272Reviewed-by: Rob Pike <r@golang.org>

Previously, we ended up passing two compiled objects for the package
being tested when linking the test executable.  Somewhat by luck, this
worked most of the time but occasionally it did not.  This changes the
linking code to not pass two objects for the same ImportPath and to
always pass the object for the test version of the package and removes
some unecessary nil checks.

Change-Id: I7bbd3fc708f14672ee2cc6aed3397421fceb8a38
Reviewed-on: https://go-review.googlesource.com/1840Reviewed-by: Ian Lance Taylor <iant@golang.org>

liblink used to encode both SETEQ BP and SETEQ CH as 0f 94 c5,
however, SETEQ BP should have used a REX prefix.

Fixes #8545.

Change-Id: Ie59c990cdd0ec506cffe4318e9ad1b48db5e57dd
Reviewed-on: https://go-review.googlesource.com/2270Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>

Fixes #9135

Change-Id: I4d0e4eb52a3d64262f107eb7eae4096a6e47ac08
Reviewed-on: https://go-review.googlesource.com/2238Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: I8f518e273c02110042b08f7c50c3d38a648c8b6e
Reviewed-on: https://go-review.googlesource.com/2281Reviewed-by: Minux Ma <minux@golang.org>

This CL adds missing ipv4-mapped ipv6 address test cases to TestParseIP.

Change-Id: I3144d2a88d409bd515cf52f8711d407bfa81ed68
Reviewed-on: https://go-review.googlesource.com/2205Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #8620

Change-Id: Idb49e586919d21d07e94a39ed9ebb0562f403460
Reviewed-on: https://go-review.googlesource.com/2221Reviewed-by: Ian Lance Taylor <iant@golang.org>

Shell out to `uname -r` this time, so that the test will compile
even if the platform doesn't have syscall.Sysctl.

Change-Id: I3a19ab5d820bdb94586a97f4507b3837d7040525
Reviewed-on: https://go-review.googlesource.com/2271Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The test program requires static constructor, which in turn needs
external linking to work, but external linking never works on 10.6.

This should fix the darwin-{386,amd64} builders.

Change-Id: I714fdd3e35f9a7e5f5659cf26367feec9412444f
Reviewed-on: https://go-review.googlesource.com/2235Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Mostly I need to tickle the builders, since I'm working on the
dashboard builders right now.

Change-Id: I833fc22bc942758a58791ed038634cdd812f5411
Reviewed-on: https://go-review.googlesource.com/2261Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ibabbca3988d39bdce584924173a912d45f50f0dd
Reviewed-on: https://go-review.googlesource.com/2243Reviewed-by: Dave Cheney <dave@cheney.net>
Reviewed-by: Minux Ma <minux@golang.org>

If the user provided a key but no value via -ldflag -X,
another linker flag was used as the value.

Placing the user's flags at the end avoids this problem.
It also provides the user the opportunity to
override existing linker flags.

Fixes #8810.

Change-Id: I96f4190713dc9a9c29142e56658446fba7fb6bc8
Reviewed-on: https://go-review.googlesource.com/2242Reviewed-by: Minux Ma <minux@golang.org>

Remove use of itod on posix systems and replace with call to itoa.
Build and use same itoa function on all systems.
Fix infinite recursion in iota function for the case -1<<63.

Change-Id: I89d7e742383c5c4aeef8780501c78a3e1af87a6f
Reviewed-on: https://go-review.googlesource.com/2213Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Updated the issue tracker link the compiler prints out
when asking for a bug report after an internal error.

Change-Id: I092b118130f131c6344d9d058bea4ad6379032b8
Reviewed-on: https://go-review.googlesource.com/2218Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Our definition of struct timespec used to cause problems with
certain versions of mingw-rt. However, as it turns out, we don't
actually need those definitions and prototypes, so remove them.

Fixes #9472.

Change-Id: Ie0880f0d58be112625140f73d0bed71f98b7cf05
Reviewed-on: https://go-review.googlesource.com/2236Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

Fixes #8501

Change-Id: I0dbbdded7f7924351c3d1841d60cb5c934b295b7
Reviewed-on: https://go-review.googlesource.com/2143Reviewed-by: Chris Manghane <cmang@golang.org>

Change-Id: Iac28c4bbe949af5628cef8ecafdd59ab5d71e6cc
Reviewed-on: https://go-review.googlesource.com/2240Reviewed-by: Keith Randall <khr@golang.org>

Preventing returning io.EOF on non-connection oriented sockets is
already applied to Unix variants. This CL applies it to Windows.

Update #4856.

Change-Id: I82071d40f617e2962d0540b9d1d6a10ea4cdb2ec
Reviewed-on: https://go-review.googlesource.com/2203Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

There is no reason to have the redundant test case TestDNSThreadLimt
because TestLookupIPDeadline does cover what we need to test with
-dnsflood flag and more.

Also this CL moves TestLookupIPDeadline into lookup_test.go to avoid
abusing to control the order of test case execution by using file name.

Change-Id: Ib417d7d3411c59d9352c03c996704d584368dc62
Reviewed-on: https://go-review.googlesource.com/2204Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes build on plan9 and windows.

Change-Id: Ic9b02c641ab84e4f6d8149de71b9eb495e3343b2
Reviewed-on: https://go-review.googlesource.com/2233Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

I missed this one in golang.org/cl/2232 and only tested the patch
on openbsd/amd64.

Change-Id: I4ff437ae0bfc61c989896c01904b6d33f9bdf0ec
Reviewed-on: https://go-review.googlesource.com/2234Reviewed-by: Minux Ma <minux@golang.org>

This is a genuine bug exposed by our test for issue 9456: our wrapper
for pthread_create is not initialized until we initialize cgo itself,
but it is possible that a static constructor could call pthread_create,
and in that case, it will be calling a nil function pointer.

Fix that by also initializing the sys_pthread_create function pointer
inside our pthread_create wrapper function, and use a pthread_once to
make sure it is only initialized once.

Fix build for openbsd.

Change-Id: Ica4da2c21fcaec186fdd3379128ef46f0e767ed7
Reviewed-on: https://go-review.googlesource.com/2232Reviewed-by: David Crawshaw <crawshaw@golang.org>

%lL will prepend the current directory to the filename, which is not
what we want here (as the file name is already absolute).

Fixes #9150.

Change-Id: I4c9386be6baf421393b92d9401a264b4692986d0
Reviewed-on: https://go-review.googlesource.com/2231Reviewed-by: Ian Lance Taylor <iant@golang.org>

Some libraries, for example, OpenBLAS, create work threads in a global constructor.
If we're doing cpu profiling, it's possible that SIGPROF might come to some of the
worker threads before we make our first cgo call. Cgocallback used to terminate the
process when that happens, but it's better to miss a couple profiling signals than
to abort in this case.

Fixes #9456.

Change-Id: I112b8e1a6e10e6cc8ac695a4b518c0f577309b6b
Reviewed-on: https://go-review.googlesource.com/2141Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ic2e34f84596b56715d5f41c9a5250f7c9f8e671b
Reviewed-on: https://go-review.googlesource.com/2087Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

Avoid the decimal lookup in digits array and compute the decimal character value directly.
Reduce calls to 64bit division on 32bit plattforms by splitting conversion into smaller blocks.
Convert value to uintptr type when it can be represented by uintptr.

on darwin/386

benchmark               old ns/op     new ns/op     delta
BenchmarkFormatInt      8352          7466          -10.61%
BenchmarkAppendInt      4281          3401          -20.56%
BenchmarkFormatUint     2785          2251          -19.17%
BenchmarkAppendUint     1770          1223          -30.90%

on darwin/amd64

benchmark               old ns/op     new ns/op     delta
BenchmarkFormatInt      5531          5492          -0.71%
BenchmarkAppendInt      2435          2295          -5.75%
BenchmarkFormatUint     1628          1569          -3.62%
BenchmarkAppendUint     726           750           +3.31%

Change-Id: Ifca281cbdd62ab7d7bd4b077a96da99eb12cf209
Reviewed-on: https://go-review.googlesource.com/2105Reviewed-by: Robert Griesemer <gri@golang.org>

+ tests that these parse:
  map[int]int{}[0]++
  interface{f()}(x).f()
  chan int(x) <- 0

Fixes #9474

Change-Id: If9fa57b3ab415ae7e93aa9935ec63edda8fe9d4f
Reviewed-on: https://go-review.googlesource.com/2178Reviewed-by: Robert Griesemer <gri@golang.org>