SignPSS is documented as allowing opts to be nil, but actually
crashes in that case. This change fixes that.

Change-Id: Ic48ff5f698c010a336e2bf720e0f44be1aecafa0
Reviewed-on: https://go-review.googlesource.com/2330Reviewed-by: Minux Ma <minux@golang.org>

First, call clearcheckmarks immediately after changing checkmark,
so that there is less time when the checkmark flag and the bitmap
are inconsistent. The tiny gap between the two lines is fine, because
the world is stopped. Before, the gap was much larger and included
such code as "go bgsweep()", which allocated.

Second, modify gcphase only when the world is stopped.
As written, gcscan_m was changing gcphase from 0 to GCscan
and back to 0 while other goroutines were running.
Another goroutine running at the same time might decide to
sleep, see GCscan, call gcphasework, and start "helping" by
scanning its stack. That's fine, except that if gcphase flips back
to 0 as the goroutine calls scanblock, it will start draining the
work buffers prematurely.

Both of these were found wbshadow=2 (and a lot of hard work).
Eventually that will run automatically, but right now it still
doesn't quite work for all.bash, due to mmap conflicts with
pthread-created threads.

Change-Id: I99aa8210cff9c6e7d0a1b62c75be32a23321897b
Reviewed-on: https://go-review.googlesource.com/2340Reviewed-by: Rick Hudson <rlh@golang.org>

Found with GODEBUG=wbshadow=2 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: I5624b509a36650bce6834cf394b9da163abbf8c0
Reviewed-on: https://go-review.googlesource.com/2310Reviewed-by: Rick Hudson <rlh@golang.org>

Fixes #9121

Change-Id: Id6ca9f259260310c4c6cbdabbc8f2fead8414e6a
Reviewed-on: https://go-review.googlesource.com/2202Reviewed-by: Minux Ma <minux@golang.org>

Change-Id: Ia18b8411bebc47ea71ac1acd9ff9dc570ec15dea
Reviewed-on: https://go-review.googlesource.com/2341Reviewed-by: Dave Cheney <dave@cheney.net>

Use typedmemmove, typedslicecopy, and adjust reflect.call
to execute the necessary write barriers.

Found with GODEBUG=wbshadow=2 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: Iec5b5b0c1be5589295e28e5228e37f1a92e07742
Reviewed-on: https://go-review.googlesource.com/2312Reviewed-by: Keith Randall <khr@golang.org>

These depend on storing arbitrary integer values using
pointer atomics, and we can't support that anymore.

Change-Id: I8cadd6d462c3eebdbe7078f43fe7c779fa8f52b3
Reviewed-on: https://go-review.googlesource.com/2311Reviewed-by: Rick Hudson <rlh@golang.org>

A side effect of this change is that when assertI2T writes to the
memory for the T being extracted, it can use typedmemmove
for write barriers.

There are other ways we could have done this, but this one
finishes a TODO in package runtime.

Found with GODEBUG=wbshadow=2 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: Icbc8aabfd8a9b1f00be2e421af0e3b29fa54d01e
Reviewed-on: https://go-review.googlesource.com/2279Reviewed-by: Keith Randall <khr@golang.org>

Found with GODEBUG=wbshadow=2 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: I1320d5340a9e421c779f24f3b170e33974e56e4f
Reviewed-on: https://go-review.googlesource.com/2278Reviewed-by: Rick Hudson <rlh@golang.org>

Found with GODEBUG=wbshadow=2 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: Iea83d693480c2f3008b4e80d55821acff65970a6
Reviewed-on: https://go-review.googlesource.com/2277Reviewed-by: Keith Randall <khr@golang.org>

Preparation for replacing many memmove calls in runtime
with typedmemmove, which is a clearer description of what
the routine is doing.

For the same reason, rename writebarriercopy to typedslicecopy.

Change-Id: I6f23bef2c2215509fefba175b16908f76dc7538c
Reviewed-on: https://go-review.googlesource.com/2276Reviewed-by: Rick Hudson <rlh@golang.org>

Add write barrier to atomic operations manipulating pointers.

In general an atomic write of a pointer word may indicate racy accesses,
so there is no strictly safe way to attempt to keep the shadow copy
in sync with the real one. Instead, mark the shadow copy as not used.

Redirect sync/atomic pointer routines back to the runtime ones,
so that there is only one copy of the write barrier and shadow logic.
In time we might consider doing this for most of the sync/atomic
functions, but for now only the pointer routines need that treatment.

Found with GODEBUG=wbshadow=1 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: I852936b9a111a6cb9079cfaf6bd78b43016c0242
Reviewed-on: https://go-review.googlesource.com/2066Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

The Gobuf.g goroutine pointer is almost always updated by assembly code.
In one of the few places it is updated by Go code - func save - it must be
treated as a uintptr to avoid a write barrier being emitted at a bad time.
Instead of figuring out how to emit the write barriers missing in the
assembly manipulation, change the type of the field to uintptr, so that
it does not require write barriers at all.

Goroutine structs are published in the allg list and never freed.
That will keep the goroutine structs from being collected.
There is never a time that Gobuf.g's contain the only references
to a goroutine: the publishing of the goroutine in allg comes first.

Goroutine pointers are also kept in non-GC-visible places like TLS,
so I can't see them ever moving. If we did want to start moving data
in the GC, we'd need to allocate the goroutine structs from an
alternate arena. This CL doesn't make that problem any worse.

Found with GODEBUG=wbshadow=1 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: I85f91312ec3e0ef69ead0fff1a560b0cfb095e1a
Reviewed-on: https://go-review.googlesource.com/2065Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Found with GODEBUG=wbshadow=1 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.

Change-Id: Ic8624401d7c8225a935f719f96f2675c6f5c0d7c
Reviewed-on: https://go-review.googlesource.com/2064Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

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>