This works by adding a call to __x86.get_pc_thunk.cx immediately before any
instruction that accesses global data and then assembling the instruction to
use the appropriate offset from CX instead of the absolute address. Some forms
cannot be assembled that way and are rewritten to load the address into CX
first.

-buildmode=pie works now, but is not yet tested.

Fixes #13201 (I think)

Change-Id: I32a8561e7fc9dd4ca6ae3b0e57ad78a6c50bf1f5
Reviewed-on: https://go-review.googlesource.com/17014Reviewed-by: Ian Lance Taylor <iant@golang.org>

I was prodded into doing this in review comments for the ARM version, and it's
going to make shared libs for 386 easier.

Change-Id: Id12de801b1425b8c6b5736fe91b418fc123a4e40
Reviewed-on: https://go-review.googlesource.com/17012Reviewed-by: David Crawshaw <crawshaw@golang.org>

Does not fix #12327 but nicer anyway.

Change-Id: I4ad730a4ca833d76957b7571895b3a08a6a530d4
Reviewed-on: https://go-review.googlesource.com/16964Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #12686.

Change-Id: I7a9f49dbd1f60b1d0240de57787753b425f9548c
Reviewed-on: https://go-review.googlesource.com/17031Reviewed-by: Ian Lance Taylor <iant@golang.org>

Cgo-created threads transition between having associated Go g's and m's and not.
A signal arriving during the transition could think it was safe and appropriate to
run Go signal handlers when it was in fact not.
Avoid the race by masking all signals during the transition.

Fixes #12277.

Change-Id: Ie9711bc1d098391d58362492197a7e0f5b497d14
Reviewed-on: https://go-review.googlesource.com/16915Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: I373a64fc30dee804d99e106d4627b780e1846917
Reviewed-on: https://go-review.googlesource.com/16999Reviewed-by: David Crawshaw <crawshaw@golang.org>

This reverts commit 7db77271.

Change-Id: I6d8855eb05ca331025dc49a5533c6da4d1fa4e84
Reviewed-on: https://go-review.googlesource.com/17030Reviewed-by: Russ Cox <rsc@golang.org>

Change-Id: Ieba62c0cb668daeb343f72fdd568e46b0b21b7d6
Reviewed-on: https://go-review.googlesource.com/16998Reviewed-by: Andrew Gerrand <adg@golang.org>

An internal link may need the C compiler support library, libgcc.a.  Add
a -libgcc option to set the name of the compiler support library.  If
-libgcc is not used, run the compiler to find it.  Permit -libgcc=none
to skip using libgcc at all and hope for the best.

Change cmd/dist to not copy libgcc into the distribution.  Add tests to
ensure that all the standard packages that use cgo can be linked in
internal mode without using libgcc.  This ensures that somebody with a
Go installation without a C compiler can build programs.

Change-Id: I8ba35fb87ab0dd20e5cc0166b5f4145b04ce52a4
Reviewed-on: https://go-review.googlesource.com/16993Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>

This includes the first parts of the general approach to PIC: load PC into CX
whenever it is needed. This is going to lead to large binaries and poor
performance but it's a start and easy to get right.

Change-Id: Ic8bf1d0a74284cca0d94a68cf75024e8ab063b4e
Reviewed-on: https://go-review.googlesource.com/16383Reviewed-by: Ian Lance Taylor <iant@golang.org>

We might be able to do better than this, but it's a start.

Change-Id: I80ebce9094e084a4746039106ccf1ad9c4b8bb7c
Reviewed-on: https://go-review.googlesource.com/16384Reviewed-by: Ian Lance Taylor <iant@golang.org>

Mostly by avoiding CX entirely, sometimes by reloading it.

I also vetted the assembly in other packages, it's all fine.

Change-Id: I50059669aaaa04efa303cf22ac228f9d14d83db0
Reviewed-on: https://go-review.googlesource.com/16386Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ie4cdf50fdaf7b368a189a84f4e2aea4cedd5ca7d
Reviewed-on: https://go-review.googlesource.com/17013Reviewed-by: Ian Lance Taylor <iant@golang.org>

BER allows the sender to choose either short form or long form where
both are legal, but DER requires the minimal one be used. Enforce this
and add a test. Fix one test which was not minimally-encoded and another
which would not distinguish rejecting the input because the long form
length wasn't minimally-encoded from rejecting it because long form was
chosen when short form was allowed.

Change-Id: I1b56fcca594dcdeddea9378b4fab427cbe7cd26d
Reviewed-on: https://go-review.googlesource.com/16517Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Adam Langley <agl@golang.org>

Otherwise _2006 is treated as _2 and then an error.

Fixes #11334

Change-Id: I40a385b45e279e9f4538bf419baab72781cdb215
Reviewed-on: https://go-review.googlesource.com/16311Reviewed-by: Rob Pike <r@golang.org>

Compare basepath and targetpath using strings.EqualFold.  The absence
of this on Windows causes an unterminating condition in `for` statement
later in the function.

Fixes #13258

Change-Id: Ib5a0caba864ee425dc75ece47b9cf6fb626f47f1
Reviewed-on: https://go-review.googlesource.com/16857
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

Only apply RFC 6724's CommonPrefixLen rule for IPv4 source/destination
pairs that are members of the same IPv4 special purpose block.

Fixes #13283.

Change-Id: I2f7c26b408dd4675dfc5c1959e22d05b43bb8241
Reviewed-on: https://go-review.googlesource.com/16995Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

On Windows, Rel emits error messages of the form `Rel: can't make
\windows relative to \windows`. Rather than emitting paths after
stripping volume names, emit the original paths so as to make those of
the form `Rel: can't make d:\windows relative to c:\windows`.  Fixed a
test that expected the error message to emit clean path instead of the
original.

Fixes #13259

Change-Id: I3a9bd5b137205f22794ec8046b4e917ee48cf750
Reviewed-on: https://go-review.googlesource.com/16858
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

no buildmode=c-shared yet.

Update golang/go#9327.

Change-Id: I9989d954d574807bac105da401c3463607fe8a99
Reviewed-on: https://go-review.googlesource.com/16700Reviewed-by: David Crawshaw <crawshaw@golang.org>

Replace the cross platform but unsafe [4]uintptr type with a OS
specific type, sigset. Most OSes already define sigset, and this
change defines a suitable sigset for the OSes that don't (darwin,
openbsd). The OSes that don't use m.sigmask (windows, plan9, nacl)
now defines sigset as the empty type, struct{}.

The gain is strongly typed access to m.sigmask, saving a dynamic
size sanity check and unsafe.Pointer casting. Also, some storage is
saved for each M, since [4]uinptr was conservative for most OSes.

The cost is that OSes that don't need m.sigmask has to define sigset.

completes ./all.bash with GOOS linux, on amd64
completes ./make.bash with GOOSes openbsd, android, plan9, windows,
darwin, solaris, netbsd, freebsd, dragonfly, all amd64.

With GOOS=nacl ./make.bash failed with a seemingly unrelated error.

R=go1.7

Change-Id: Ib460379f063eb83d393e1c5efe7333a643c1595e
Reviewed-on: https://go-review.googlesource.com/16942Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The NamePos value was not being set, and would default to a value
of zero. This would cause the printing logic to get confused as
to where exactly to place the "Has unexported fields" string.

A trivial package changes from

<
type A struct {
	A int // A
	B int
			// B
	// Has unexported fields.
}
>

to

<
type A struct {
	A int // A
	B int // B
	// Has unexported fields.
}
>

Fixes #12971

Change-Id: I53b7799a1f1c0ad7dcaddff83d9aaeb1d6b7823e
Reviewed-on: https://go-review.googlesource.com/16286
Run-TryBot: Joe Tsai <joetsai@digital-static.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

golang.org/cl/16796 broke android/386 by assuming behaviour specific to glibc's
dynamic linker. Copy bionic by using int $0x80 to invoke syscalls on
android/386 as the old alternative (CALL *runtime_vdso(SB)) cannot be compiled
without text relocations, which we want to get rid of on android.

Also remove "CALL *runtime_vdso(SB)" variant from the syscall package.

Change-Id: I6c01849f8dcbd073d000ddc8f13948a836b8b261
Reviewed-on: https://go-review.googlesource.com/16996
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Fixes #12778

Change-Id: I2ca53180d46180b951749abe453fd560d0f1d9d6
Reviewed-on: https://go-review.googlesource.com/16950Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Id164a099e0ac8bd231ee7ed8d7b7a34c91f5f68f
Reviewed-on: https://go-review.googlesource.com/16991
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Completes sniffing for mp4 signature according
to the spec at:
  https://mimesniff.spec.whatwg.org/#signature-for-mp4
Clause 6.2.1

Fixes #8773

Change-Id: Icfc4a23324ae249db52c94a21c0e8509e1833e19
Reviewed-on: https://go-review.googlesource.com/16951Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Not all tests passing yet, but a good chunk are.

Change-Id: I5daebaeabf3aecb380674ece8830a86751a8d139
Reviewed-on: https://go-review.googlesource.com/16458Reviewed-by: Rahul Chaudhry <rahulchaudhry@google.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Inspect the crypto/tls error to recognize this case and give a more
helpful error.

Fixes #11111.

Change-Id: I63f6af8c375aa892326ccccbd29655d54d68df0b
Reviewed-on: https://go-review.googlesource.com/16079
Run-TryBot: Caleb Spare <cespare@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The line correction when reporting a missing package clause
was removed before since it wasn't clear that it was needed.
Added it again because of issue 13267.

No explicit test case has been added to test/fixedbugs because
it would require a file that contains a single byte and such a
file doesn't fit the existing test harness. Instead documented
the problematic line in the parser for future reference.

Fixes #13267.

Change-Id: I590fe8f358042aab73acf16c2ed9567872b174f4
Reviewed-on: https://go-review.googlesource.com/16975Reviewed-by: Chris Manghane <cmang@golang.org>

Issue #13248 was fixed by https://go-review.googlesource.com/#/c/16930/.
This is the corresponding test case (original offending program).

Change-Id: I7c99783db74a5422704409cea7e5073094beadd3
Reviewed-on: https://go-review.googlesource.com/16973Reviewed-by: Chris Manghane <cmang@golang.org>

Fixes #13274.
Fixes #13272.

Change-Id: Ie67a2c4671ee2b49831898fff7677cd65d780942
Reviewed-on: https://go-review.googlesource.com/16972Reviewed-by: Chris Manghane <cmang@golang.org>

Fixes #13266.

Change-Id: I31da922e0599989e52acf346374c2077b157ebb7
Reviewed-on: https://go-review.googlesource.com/16971Reviewed-by: Chris Manghane <cmang@golang.org>

Currently, if an allocation is large enough that arena_end + size
overflows (which is not hard to do on 32-bit), we go ahead and call
sysReserve with the impossible base and length and depend on this to
either directly fail because the kernel can't possibly fulfill the
requested mapping (causing mheap.sysAlloc to return nil) or to succeed
with a mapping at some other address which will then be rejected as
outside the arena.

In order to make this less subtle, less dependent on the kernel
getting all of this right, and to eliminate the hopeless system call,
add an explicit overflow check.

Updates #13143. This real issue has been fixed by 0de59c27, but this is
a belt-and-suspenders improvement on top of that. It was uncovered by
my symbolic modeling of that bug.

Change-Id: I85fa868a33286fdcc23cdd7cdf86b19abf1cb2d1
Reviewed-on: https://go-review.googlesource.com/16961
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Issue introduced by https://go-review.googlesource.com/#/c/16920/ .

TBR=rsc

Change-Id: I2a0e0c81f641f869568230837c566913f6538f37
Reviewed-on: https://go-review.googlesource.com/16990
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

mcache.tiny is in non-GC'd memory, but points to heap memory. As a
result, there may or may not be write barriers when writing to
mcache.tiny. Make it clearer that funny things are going on by making
mcache.tiny a uintptr instead of an unsafe.Pointer.

Change-Id: I732a5b7ea17162f196a9155154bbaff8d4d00eac
Reviewed-on: https://go-review.googlesource.com/16963
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The tiny alloc cache is maintained in a pointer from non-GC'd memory
(mcache) to heap memory and hence must be handled carefully.

Currently we clear the tiny alloc cache during sweep termination and,
if it is assigned to a non-nil value during concurrent marking, we
depend on a write barrier to keep the new value alive. However, while
the compiler currently always generates this write barrier, we're
treading on thin ice because write barriers may not happen for writes
to non-heap memory (e.g., typedmemmove). Without this lucky write
barrier, the GC may free a current tiny block while it's still
reachable by the tiny allocator, leading to later memory corruption.

Change this code so that, rather than depending on the write barrier,
we simply clear the tiny cache during mark termination when we're
clearing all of the other mcaches. If the current tiny block is
reachable from regular pointers, it will be retained; if it isn't
reachable from regular pointers, it may be freed, but that's okay
because there won't be any pointers in non-GC'd memory to it.

Change-Id: I8230980d8612c35c2997b9705641a1f9f865f879
Reviewed-on: https://go-review.googlesource.com/16962
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The user can inspect the record data to detect that the other side is
not using the TLS protocol.

This will be used by the net/http client (in a follow-on CL) to detect
when an HTTPS client is speaking to an HTTP server.

Updates #11111.

Change-Id: I872f78717aa8e8e98cebd8075436209a52039a73
Reviewed-on: https://go-review.googlesource.com/16078Reviewed-by: Adam Langley <agl@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This simplifies covering all cases, reducing the number of branches
and making unrolling for simpler functions manageable.
This significantly improves performance of non-ASCII input.

This change will also allow addressing Issue #11733 in an efficient
manner.

RuneCountTenASCIIChars-8             13.7ns ± 4%  13.5ns ± 2%     ~     (p=0.116 n=7+8)
RuneCountTenJapaneseChars-8           153ns ± 3%    74ns ± 2%  -51.42%  (p=0.000 n=8+8)
RuneCountInStringTenASCIIChars-8     13.5ns ± 2%  12.5ns ± 3%   -7.13%  (p=0.000 n=8+7)
RuneCountInStringTenJapaneseChars-8   145ns ± 2%    68ns ± 2%  -53.21%  (p=0.000 n=8+8)
ValidTenASCIIChars-8                 14.1ns ± 3%  12.5ns ± 5%  -11.38%  (p=0.000 n=8+8)
ValidTenJapaneseChars-8               147ns ± 3%    71ns ± 4%  -51.72%  (p=0.000 n=8+8)
ValidStringTenASCIIChars-8           12.5ns ± 3%  12.3ns ± 3%     ~     (p=0.095 n=8+8)
ValidStringTenJapaneseChars-8         146ns ± 4%    70ns ± 2%  -51.62%  (p=0.000 n=8+7)
DecodeASCIIRune-8                    5.91ns ± 2%  4.83ns ± 3%  -18.28%  (p=0.001 n=7+7)
DecodeJapaneseRune-8                 12.2ns ± 7%   8.5ns ± 3%  -29.79%  (p=0.000 n=8+7)
FullASCIIRune-8                      5.95ns ± 3%  4.27ns ± 1%  -28.23%  (p=0.000 n=8+7)
FullJapaneseRune-8                   12.0ns ± 6%   4.3ns ± 3%  -64.39%  (p=0.000 n=8+8)

Change-Id: Iea1d6b0180cbbee1739659a0a38038126beecaca
Reviewed-on: https://go-review.googlesource.com/16940Reviewed-by: Russ Cox <rsc@golang.org>

Fixes #11590.

Change-Id: I4144107334604a2cc98c7984df3b5d4cde3d30af
Reviewed-on: https://go-review.googlesource.com/16920Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #11699.

Change-Id: I01bf506d76260bcdf828bbde52791e328aa441a5
Reviewed-on: https://go-review.googlesource.com/16921Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #11359.

Change-Id: I0fdfa410939f7e42020cbb19d74a67e1cc3cd610
Reviewed-on: https://go-review.googlesource.com/16919Reviewed-by: Ian Lance Taylor <iant@golang.org>