EvalSymlinks returns error if given path or its target path don't exist.
Add a test for future improvement.

Change-Id: Ic9a4aa5eaee0fe7ac523d54d8eb3132a11b380b3
Reviewed-on: https://go-review.googlesource.com/27330Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>

This change adds runtime/trace support to go tool compile.

Change-Id: I6c496b9b063796123f75eba6af511c53a57c0196
Reviewed-on: https://go-review.googlesource.com/25354
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

Add checks for failure of CreateEvent, SetEvent or
WaitForSingleObject. Any failures are considered fatal and
will throw() after printing an informative message.

Updates #16646

Change-Id: I3bacf9001d2abfa8667cc3aff163ff2de1c99915
Reviewed-on: https://go-review.googlesource.com/26655Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This cosmetic change defines ld.FlagTextAddr using ld.HEADR in
the Plan 9 cases, like it is done for other operating systems.

Change-Id: Ic929c1c437f25661058682cf3e159f0b16cdc538
Reviewed-on: https://go-review.googlesource.com/30912
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Also removes unnecessary allocation.

Change-Id: I3406cf75a7b64d93b2b99c7f1f5c78f580452b60
Reviewed-on: https://go-review.googlesource.com/30891
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Support for multiple text sections was added in CL 27790.
However, this change broke the build on plan9/amd64.

In relocsym, the R_ADDROFF relocation was changed to
use offsets relative to the start of the first text
section. However, Segtext.Vaddr is the address of
the text segment, while we expect to start from
the first section (text.runtime) of the text segment.

Fixes #17411.

Change-Id: I86bbcbda81cea735b0ecf156eab2e6e5d63acce3
Reviewed-on: https://go-review.googlesource.com/30911
Run-TryBot: David du Colombier <0intro@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

All the implementations of NsecToTimespec and NsecToTimeval were the
same other than types. Write a single version that uses
GOARCH/GOOS-specific setTimespec and setTimeval functions to handle the
types.

The logic in NsecToTimespec and NsecToTimeval caused times before 1970
to have a negative usec/nsec. The Linux kernel requires that usec
contain a positive number; for consistency, we do this for both
NsecToTimespec and NsecToTimeval.

Change-Id: I525eaba2e7cdb00cb57fa00182dabf19fec298ae
Reviewed-on: https://go-review.googlesource.com/30826
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

The new implementation parses the plan9 interface files
and builds Interface representations for the net package.

Updates #17218

Change-Id: I3199d18d9e96a17e922186c3abff1d7cd9cbec2e
Reviewed-on: https://go-review.googlesource.com/29963
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Show usage of os.IsNotExist in an example.

Change-Id: I5306ea06c370099de5b02668dfa02b87b0c2beac
Reviewed-on: https://go-review.googlesource.com/25571Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Support the tagging of binaries created with the internal linker
on Solaris as having a non-executable stack by writing a PT_SUNWSTACK
program header.

Fixes #16074

Change-Id: I3888f2153083385d04a52f341570f93e5738b276
Reviewed-on: https://go-review.googlesource.com/24142
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

To prevent slice growth when appending.

Change-Id: I2cdb9b09bc33f63188b19573c8b9a77601e63801
Reviewed-on: https://go-review.googlesource.com/23783
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Updates #15978
Updates #16145

Change-Id: I161f5bc97d41c08bf5e1405ccafa86232d70886d
Reviewed-on: https://go-review.googlesource.com/25320
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

The error coming out of matchGoImport does not differentiate between
having no imports, and having some invalid imports.

This some extra context to the error message to help debug these issues.

Fixes #16467

Change-Id: I3e9a119ed73da1bed5e07365be0221ea6b7f19db
Reviewed-on: https://go-review.googlesource.com/25121
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

If strict option is enabled, when decoding, instead of skip the padding
bits, it will do strict check to enforce they are set to zero.

Fixes #15656

Change-Id: I869fb725a39cc9dde44dbc4ff0046446e7abc642
Reviewed-on: https://go-review.googlesource.com/24964Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Simplify map key literals in "gofmt -s"

Fixes #16461.

Change-Id: Ia61739b34a30ac27f6696f94a98809109a8a7b61
Reviewed-on: https://go-review.googlesource.com/25530
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Update the description of the conditions under which highlighting might
be misleading.

Fixes #16754

Change-Id: I3078a09e0b9a76d12078352e15a3f26ba3f1bbee
Reviewed-on: https://go-review.googlesource.com/30818Reviewed-by: David Chase <drchase@google.com>

This is a followup to CL 24747, where the package doc phrase
"Functions in this package replace occurrences of slash unless otherwise specified."
was removed. The phrase was originally added in CL 7310 together
with this explicit opt out statement for SplitList.

Remove it since it's no longer neccessary. This helps consistency.

Updates #16111.
Updates #10122.

Change-Id: Iba86de57c24100adecac9cb5892ce180126c0ea6
Reviewed-on: https://go-review.googlesource.com/25250Reviewed-by: Russ Cox <rsc@golang.org>

Fix typo in word synchronization in comments.

Change-Id: I453b4e799301e758799c93df1e32f5244ca2fb84
Reviewed-on: https://go-review.googlesource.com/25174Reviewed-by: Russ Cox <rsc@golang.org>

The canBackTrace variable is true for all of the architectures
Go supports and this is likely to remain the case as new
architectures are added.

Change-Id: I73900c018eb4b2e5c02fccd8d3e89853b2ba9d90
Reviewed-on: https://go-review.googlesource.com/22423Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

When generating callgrind format output, produce cost lines at
instruction granularity. This allows visualizers supporting the
callgrind format to display instruction-level profiling information.

We also need to provide the object file (ob=) in order for tools to find
the object file to disassemble when displaying assembly.

We opportunistically group cost lines corressponding to the same
function together, reducing the number of superfluous description lines.
Subposition compression (relative position numbering) is also used to
reduce the output size.

Change-Id: Id8e960b81dc7a47ec1dfbae877521f76972431c4
Reviewed-on: https://go-review.googlesource.com/23781
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Raul Silvera <rsilvera@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>

The trace tool can generate some interesting profiles, but it was only
exposing them as svg through the web UI.  This adds command line options
to generate the raw pprof file.

Change-Id: I52e4f909fdca6f65c3616add444e3892783640f4
Reviewed-on: https://go-review.googlesource.com/23324Reviewed-by: Russ Cox <rsc@golang.org>

All implementations of these functions are identical.

Change-Id: I7cbea53c02bb0cee75e30beed19d29ba0a7ef657
Reviewed-on: https://go-review.googlesource.com/30819
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: I1a2504ad9ca8607588d2d366598115fe360435b5
Reviewed-on: https://go-review.googlesource.com/30870Reviewed-by: Ian Lance Taylor <iant@golang.org>

We should preserve the fact that a roundtrip read on fields with the zero
value should remain the zero for those that are reasonable to stay that way.
If the zero value for a MS-DOS timestamp was used, then it is sensible for
that zero value to also be read back later.

Fixes #17403

Change-Id: I32c3915eab180e91ddd2499007374f7b85f0bd76
Reviewed-on: https://go-review.googlesource.com/30811
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Shrinks cmd/go's text segment by 0.9%.

   text	   data	    bss	    dec	    hex	filename
6447148	 231643	 146328	6825119	 68249f	go.before
6387404	 231643	 146328	6765375	 673b3f	go.after

Change-Id: I431e8482dbb11a7c1c77f2196cada43d5dad2981
Reviewed-on: https://go-review.googlesource.com/30817Reviewed-by: Austin Clements <austin@google.com>

Also, fix a byte-ordering problem with stack maps for assembly
function signatures on big-endian targets.

Change-Id: I6e8698f5fbb04b31771a65f4a8f3f9c045ff3c98
Reviewed-on: https://go-review.googlesource.com/30816Reviewed-by: Austin Clements <austin@google.com>

We save and restore the link register in non-leaf functions because
it is clobbered by CALLs. It is therefore available for general
purpose use.

Only enabled on s390x currently. The RC4 benchmarks in particular
benefit from the extra register:

name     old speed     new speed     delta
RC4_128  243MB/s ± 2%  341MB/s ± 2%  +40.46%  (p=0.008 n=5+5)
RC4_1K   267MB/s ± 0%  359MB/s ± 1%  +34.32%  (p=0.008 n=5+5)
RC4_8K   271MB/s ± 0%  362MB/s ± 0%  +33.61%  (p=0.008 n=5+5)

Change-Id: Id23bff95e771da9425353da2f32668b8e34ba09f
Reviewed-on: https://go-review.googlesource.com/30597Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The Subject and Issuer names in a certificate look like they should be a
list of key-value pairs. However, they're actually a list of lists of
key-value pairs. Previously we only looked at the first element of each
sublist and the vast majority of certificates only have one element per
sublist.

However, it's possible to have multiple elements and some 360
certificates from the “Pilot” log are so constructed.

This change causes all elements of the sublists to be processed.

Fixes #16836.

Change-Id: Ie0a5159135b08226ec517fcf251aa17aada37857
Reviewed-on: https://go-review.googlesource.com/30810Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Ib14b5421bb5e407bbd4d3cbfc68c92d3dd257cb1
Reviewed-on: https://go-review.googlesource.com/30732
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

In some cases the members of the root set from which flood
runs themselves escape, without their referents being also
tagged as escaping.  Fix this by reflooding from those roots
whose escape increases, and also enhance the "leak" test to
include reachability from a heap-escaped root.

Fixes #17318.

Change-Id: Ied1e75cee17ede8ca72a8b9302ce8201641ec593
Reviewed-on: https://go-review.googlesource.com/30693
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

A later CL will be adding more code here.
It will help to keep it separate from the other code.

Change-Id: I971ba53de819cd10991b51fdec665984939a5f9b
Reviewed-on: https://go-review.googlesource.com/30709Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The Montgomery multiply code is applicable to this case
but was being bypassed. Don't do that.

The old test len(x) > 1 was really just a bad approximation to x > 1.

name    old time/op  new time/op  delta
Exp-8   5.56ms ± 4%  5.73ms ± 3%     ~     (p=0.095 n=5+5)
Exp2-8  7.59ms ± 1%  5.66ms ± 1%  -25.40%  (p=0.008 n=5+5)

This comes up especially when doing Fermat (Miller-Rabin)
primality tests with base 2.

Change-Id: I4cc02978db6dfa93f7f3c8f32718e25eedb4f5ed
Reviewed-on: https://go-review.googlesource.com/30708Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This way you can still run 'go test' or 'go bench -run Foo'
without wondering why it is taking so very long.

Change-Id: Icfa097a6deb1d6682acb7be9f34729215c29eabb
Reviewed-on: https://go-review.googlesource.com/30707Reviewed-by: Robert Griesemer <gri@golang.org>

Change-Id: I59f7afa7a5803d19f8b21fe70fc85ef997bb3a85
Reviewed-on: https://go-review.googlesource.com/30542
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>

ARM direct CALL/JMP instruction has 24 bit offset, which can only
encodes jumps within +/-32M. When the target is too far, the top
bits get truncated and the program jumps wild.

This CL detects too-far jumps and automatically insert trampolines,
currently only internal linking on ARM.

It is necessary to make the following changes to the linker:
- Resolve direct jump relocs when assigning addresses to functions.
  this allows trampoline insertion without moving all code that
  already laid down.
- Lay down packages in dependency order, so that when resolving a
  inter-package direct jump reloc, the target address is already
  known. Intra-package jumps are assumed never too far.
- a linker flag -debugtramp is added for debugging trampolines:
    "-debugtramp=1 -v" prints trampoline debug message
    "-debugtramp=2"    forces all inter-package jump to use
                       trampolines (currently ARM only)
    "-debugtramp=2 -v" does both
- Some data structures are changed for bookkeeping.

On ARM, pseudo DIV/DIVU/MOD/MODU instructions now clobber R8
(unfortunate). In the standard library there is no ARM assembly
code that uses these instructions, and the compiler no longer emits
them (CL 29390).

all.bash passes with -debugtramp=2, except a disassembly test (this
is unavoidable as we changed the instruction).

TBD: debug info of trampolines?

Fixes #17028.

Change-Id: Idcce347ea7e0af77c4079041a160b2f6e114b474
Reviewed-on: https://go-review.googlesource.com/29397Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

If we get a SIGPROF on a non-Go thread, and the program has not called
runtime.SetCgoTraceback so we have no way to collect a stack trace, then
record a profile that is just the PC where the signal occurred. That
will at least point the user to the right area.

Retrieving the PC from the sigctxt in a signal handler on a non-G thread
required marking a number of trivial sigctxt methods as nosplit, and,
for extra safety, nowritebarrierrec.

The test shows that the existing test CgoPprofThread test does not test
the stack trace, just the profile signal. Leaving that for later.

Change-Id: I8f8f3ff09ac099fc9d9df94b5a9d210ffc20c4ab
Reviewed-on: https://go-review.googlesource.com/30252
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

When starting tracing, EvGoCreate events are added for existing
goroutines that may have been blocking in syscall. EvGoCreate
increments the runnable goroutine count. This change makes the
following EvGoInSyscall event decrement the runnable goroutine count
because we now know that goroutine is in syscall, and not runnable.

Made generateTrace return an error, at any given time, the number
of runnable/running/insyscall goroutines becomes non-negative.

Added a basic test that checks the number of runnable/running
goroutines don't include the goroutines in syscall - the test failed
before this change.

Change-Id: Ib732c382e7bd17158a437576f9d589ab89097ce6
Reviewed-on: https://go-review.googlesource.com/25552
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>

CL 14472 solved issue #12030 by explicitly linking msvcrt.dll
to every cgo executable we build. This CL achieves the same
by manually loading ntdll.dll during startup.

Updates #12030

Change-Id: I5d9cd925ef65cc34c5d4031c750f0f97794529b2
Reviewed-on: https://go-review.googlesource.com/30737
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>

The (pc, line) deltas in the line number information are currently encoded
either with a special opcode, or with a triplet of DW_LNS_advance_pc,
DW_LNS_advance_line, and DW_LNS_copy instructions.  Instead of DW_LNS_copy,
this change always uses a special opcode, which can make DW_LNS_advance_pc or
DW_LNS_advance_line unnecessary, or make their operands take fewer bytes.  It
chooses the special opcode so that the encoding of the remaining deltas is as
small as possible.

Use DW_LNS_const_add_pc or DW_LNS_fixed_advance_pc instead of DW_LNS_advance_pc
for deltas where they save a byte.

Update LINE_BASE and LINE_RANGE constants to optimal values for this strategy.

This reduces line number information by about 35% and total size by about 2%
for a typical binary.

Change-Id: Ia61d6bf19c95c1d34ba63c67ed32b376beda225f
Reviewed-on: https://go-review.googlesource.com/30577Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

- Add new BenchmarkQuoRem.
- Eliminate allocation in divLarge nat pool
- Unroll mulAddVWW body 4x
- Remove some redundant slice loads in divLarge

name      old time/op  new time/op  delta
QuoRem-8  2.18µs ± 1%  1.93µs ± 1%  -11.38%  (p=0.000 n=19+18)

The starting point in the comparison here is Cherry's
pending CL to turn mulWW and divWW into intrinsics.
The optimizations in divLarge work best because all
the function calls are gone. The effect of this CL is not
as large if you don't assume Cherry's CL.

Change-Id: Ia6138907489c5b9168497912e43705634e163b35
Reviewed-on: https://go-review.googlesource.com/30613
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>