R_ADDRCUOFF refers to the offset from the start of the
compilation unit. Now that we could have multiple compilation
units per package, we should use the start of the compilation
unit, instead of the start of the package.

Change-Id: I3d6a3c5a5c47c9ccf88091ed05413ced826f9934
Reviewed-on: https://go-review.googlesource.com/c/go/+/204828
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>

Clean merge.

Change-Id: I26a4e3d4c09a928c9fd95e394304ee10319ca7c5

Currently, at compile time we emit a function DIE with '"".' in
the function name, and we expand it at link time, with a really
ugly function. We can just expand it at compile time instead.
This way, we don't need to modify the symbol content at link time,
and also no need to allocate memory for that.

Keep the linker expansion, in case the compiler is invoked
without the import path.

Change-Id: Id53cd2e2d3eb61efceb8d44479c4b6ef890baa43
Reviewed-on: https://go-review.googlesource.com/c/go/+/204826Reviewed-by: Than McIntosh <thanm@google.com>

Change-Id: I2e52206a95c9463df5661664726a8b3bbf3ad1fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/204825Reviewed-by: Than McIntosh <thanm@google.com>

In the deadcode pass, we use a work queue for the flood algorithm.
Currently this is a simple LIFO queue. In this order, there is
poor locality in accessing object files.

Since the global indices are assigned in package DAG order, edges
are mostly either within a package or from a smaller index to a
larger one. (With named symbols, there can be backward edges, but
shouldn't be too many.) Using a min-heap for the work queue, we
access all symbols in one object, then move to next one. It
rarely needs to revisit an object that is already visted. This
should result in better locality.

Benchmark result from Than (thanks!):

name                      old time/op       new time/op       delta
LinkCompiler                    1.74s ±11%        1.61s ± 9%  -7.80%  (p=0.000 n=20+19)
LinkWithoutDebugCompiler        1.27s ±11%        1.15s ± 9%  -9.02%  (p=0.000 n=20+20)

Currently this uses the container/heap package, which uses
interface elements. If this allocates too much, we may consider
to hand-code the min heap.

Change-Id: I216d5291c432fe1f40b0b8f4f1b9d388807bf6c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/204438Reviewed-by: Jeremy Faller <jeremy@golang.org>

Currently in the linker we load internal packges first, then the
main package, and then load imported packages following the
dependency graph. As a result, packages are loaded mostly in the
dependency order, except the internal packages. The global symbol
indices are assigned the same way.

By loading the internal packages at the end, the packages are
loaded in the dependency order, so are the global indices. This
way, a relocation edge is mostly either within a packge or a
forward edge from a smaller index to a larger one. This allows
us to use a min-heap work queue in the deadcode pass, to achieve
better spatial locality (in the next CL).

Change-Id: I01fa9b3cf0c9e9e66006040f6378a51fd78f0f39
Reviewed-on: https://go-review.googlesource.com/c/go/+/204437Reviewed-by: Jeremy Faller <jeremy@golang.org>

Cgo internal linking was disabled when switching to new object
files. Reeanble the tests, as they get supported.

Change-Id: I11d2ac8785cce73f3a42f6935c10d9f067bc90a4
Reviewed-on: https://go-review.googlesource.com/c/go/+/204520Reviewed-by: Than McIntosh <thanm@google.com>

Change-Id: I0fe88df182f13e7f04c8de0b82e111db441a26e2
Reviewed-on: https://go-review.googlesource.com/c/go/+/204341
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>

Fixes #34778

Change-Id: If8225a7c41cb2af3f67157fb9670eef86272e85e
Reviewed-on: https://go-review.googlesource.com/c/go/+/204997
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Even though bitwise operations may be slightly more
performant, the readability improvement of a mod
operation is worth the tradeoff.

Change-Id: I352c92ad355c6eb6ef99e3da00e1eff2d2ea5812
Reviewed-on: https://go-review.googlesource.com/c/go/+/204739Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Updates #10958
Updates #24543
Fixes #35294

Change-Id: I60f024d08451565df6d9751dab9832b50cbf637a
Reviewed-on: https://go-review.googlesource.com/c/go/+/204957
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

On illumos systems, and at least historically on Solaris systems, it is
possible for port_getn(3C) calls to return some number of events and
then fail with error ETIME.

Generally we expect this to happen if the caller passes an nget value
larger than 1 and calls with a timeout; if less than the requested
number of events accumulate the system will still return them after
timeout failure so the caller must check the updated nget value in the
ETIME case.  Note that although less likely this can still happen even
when requesting just 1 event, especially with a short timeout value or
on a busy system.

Fixes #35261

Change-Id: I0d83251b69a2fadc64c4e8e280aa596e2e1548ba
Reviewed-on: https://go-review.googlesource.com/c/go/+/204801Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Goroutines clean up takes longer when using deprecated CloseNotifier.

Fixes #35122

Change-Id: Id820a3012b5c781ddfb294b38ee3b009624e398c
Reviewed-on: https://go-review.googlesource.com/c/go/+/204661
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

In newobj mode, cgo attributes are typically set later, as we
create sym.Symbols later. But when internal cgo linking, the
host object loaders still work with sym.Symbols, and the cgo
attributes need to be set for them to work properly. Therefore,
set them early. This will cause creating some Symbols eagerly,
but they are mostly host object symbols and will need to be
created anyway.

Now all cgo internal linking tests pass on ELF systems.

Change-Id: I023a4df4429acc8ebf5e185f62e6809198497a78
Reviewed-on: https://go-review.googlesource.com/c/go/+/204857Reviewed-by: Than McIntosh <thanm@google.com>

If multiple goroutines call time.(*Timer).Reset then the timer will go
from timerWaiting to timerDeleted to timerModifying to timerModifiedLater.
The timer can be on a different P, meaning that simultaneously cleantimers
could change it from timerDeleted to timerRemoving to timerRemoved.
If Reset sees timerRemoved, it was doing an atomic.Store of timerWaiting,
meaning that it did not necessarily see the other values set in the timer,
so the timer could appear to be in an inconsistent state. Use atomic.Cas
to avoid that possibility.

Updates #6239
Updates #27707
Fixes #35272

Change-Id: I1d59a13dc4f2ff4af110fc6e032c8c9d59cfc270
Reviewed-on: https://go-review.googlesource.com/c/go/+/204717
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

In CL 204617, I intend to make "bound" parameter to have special meaning
in typecheckarraylit, so we can distinguish between type-checks array
literal and slice literal. But we end up with other solution. The CL was
submitted without reverting the "bound" parameter in case of slice
literal.

Technically, it's not harmful, but causes the code harder to read and maintain.

Change-Id: Ia522ccc9a6b8e25d7eaad4aa4957cb4fa18edc60
Reviewed-on: https://go-review.googlesource.com/c/go/+/204618
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

User's program was mutating time.Local variable and crashing
itself as a consequence. Instead of documenting that time.Local
variable should not be mutated, recommended way of setting the
system's time zone has been documented.

Fixes #34814

Change-Id: I7781189855c3bf2ea979dfa07f86c283eed27091
Reviewed-on: https://go-review.googlesource.com/c/go/+/200457Reviewed-by: Ian Lance Taylor <iant@golang.org>

I was doing some testing with GODEBUG=schedtrace=1,scheddetail=1 and I
noticed that the program hung after a throw with "all goroutines are
asleep". This is because when doing a throw or fatal panic with schedtrace
the panic code does a final schedtrace, which needs to acquire the
scheduler lock. The checkdead function is always called with the scheduler
lock held. So checkdead would throw with the scheduler lock held, then
the panic code would call schedtrace, which would block trying to acquire
the scheduler lock.

This problem will only happen for people debugging the runtime, but
it's easy to avoid by having checkdead unlock the scheduler lock before
it throws. I only did this for the throws that can happen for a normal
program, not for throws that indicate some corruption in the scheduler data.

Change-Id: Ic62277b3ca6bee6f0fca8d5eb516c59cb67855cb
Reviewed-on: https://go-review.googlesource.com/c/go/+/204778
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This change turns off the scavenger if there's less than one physical
page of work to do. If there's less than one phyiscal page of work
today, then the computed time for the work to be done will be zero,
resulting in a floating point division by zero.

This is bad on two accounts. On the one hand it could cause a fault on
some systems. On the other hand, it could cause the pacing computations
done by the scavenger to be nonsense. While this is generally harmless
in the case where there's a very small amount of work to do anyway (the
scavenger might just back off expontentially forever, or do some work
and immediately sleep, because there's not much of it to do), it causes
problems for the deadlock checker. On platforms with a larger physical
page size, such as 64 KiB, we might hit this path in a deadlock
scenario, in which case the deadlock checker will never fire and we'll
just hang.

Specifically, this happens on ppc64 trybot tests, which is where the
issue was discovered.

Fixes #34575.

Change-Id: I8677db539447b2f0e75b8cfcbe33932244e1508c
Reviewed-on: https://go-review.googlesource.com/c/go/+/203517
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

For debugging. (The "go1.4" can be misleading since it might actually
be go1.4.3 or go1.11 or go1.12 or master)

Change-Id: I27520b931a2be018de577a299592d082260aa467
Reviewed-on: https://go-review.googlesource.com/c/go/+/204757
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Suppress “finding” messages unless they are unusually slow, and
“extracting” messages always (they almost always occur conjunction
with “downloading”, which is already logged).

Log “found” messages for module dependencies added to satisfy missing
import paths.

Log top-level version changes in 'go get' when the selected version
is not identical to the version requested on the command line.

Updates #26152
Updates #33284

Change-Id: I4d0de60fab58d7cc7df8a2aff05c8b5b2220e626
Reviewed-on: https://go-review.googlesource.com/c/go/+/204777
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

A majority of work is spent in dataSize when en/decoding the same
struct over and over again. This wastes a lot of work, since
the result doesn't change for a given reflect.Value.

Cache the result of the function for structs, so that subsequent
calls to dataSize can avoid doing work.

    name         old time/op    new time/op     delta
    ReadStruct     1.00µs ± 1%     0.37µs ± 1%   -62.99%  (p=0.029 n=4+4)
    WriteStruct    1.00µs ± 3%     0.37µs ± 1%   -62.69%  (p=0.008 n=5+5)

    name         old speed      new speed       delta
    ReadStruct   75.1MB/s ± 1%  202.9MB/s ± 1%  +170.16%  (p=0.029 n=4+4)
    WriteStruct  74.8MB/s ± 3%  200.4MB/s ± 1%  +167.96%  (p=0.008 n=5+5)

Fixes #34471

Change-Id: Ic5d987ca95f1197415ef93643a0af6fc1224fdf0
Reviewed-on: https://go-review.googlesource.com/c/go/+/199539Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Iae1ca888729014b6fec97d7bd7ae082dbceb9fe5
Reviewed-on: https://go-review.googlesource.com/c/go/+/204837
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>

Updates #30185
Updates #33326
Updates #34822

Change-Id: Ie13651585898d1bbbf4f779b97ee50b6c7e7ad50
Reviewed-on: https://go-review.googlesource.com/c/go/+/204521
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>

Change the loader to do more bulk allocation when making slices of
small objects (sym.Reloc, etc) as part of creating and populating
sym.Symbols in loader.LoadFull(). This replaces a large number of
small allocations with a smaller number of large allocations,
improving performace. Compilebench numbers (linker portion) for this
change:

name                      old time/op       new time/op       delta
LinkCompiler                    1.71s ±11%        1.57s ± 9%   -8.35%  (p=0.000 n=19+20)
LinkWithoutDebugCompiler        1.19s ±14%        1.10s ±13%   -7.93%  (p=0.000 n=20+19)

name                      old user-time/op  new user-time/op  delta
LinkCompiler                    1.86s ±15%        1.34s ±10%  -28.02%  (p=0.000 n=20+20)
LinkWithoutDebugCompiler        1.05s ±14%        0.95s ± 9%   -9.17%  (p=0.000 n=19+20)

Hyperkube from kubernetes doesn't show any significant benefit (which
seems a little surprising).

Change-Id: Ide97f78532fb60b08bb6e4cfa097e9058f7ea8ab
Reviewed-on: https://go-review.googlesource.com/c/go/+/203457
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Based on the riscv-go port and the linux/riscv64 files in x/sys/unix.

Updates #27532

Change-Id: Ib33a59a61f6b2721b12292c18f1fc9f9d0509cd3
Reviewed-on: https://go-review.googlesource.com/c/go/+/204659
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

config.go needs to be removed from this CL.

Change-Id: I04a267feeae1551bb18f6a03a725adc9db593fdb
Reviewed-on: https://go-review.googlesource.com/c/go/+/204099Reviewed-by: Cherry Zhang <cherryyz@google.com>

The current implementation performs a plain map lookup,
but other header methods canonicalize header keys before
using them.

Fixes #34918

Change-Id: Id4120488b8b39ecee97fa7a6ad8a34158687ffcd
Reviewed-on: https://go-review.googlesource.com/c/go/+/201357Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixed a couple of minor conflicts in lib.go and deadcode.go
relating to debug logging.

Change-Id: I58335fc42ab1f1f3409fd8354da4f26419e8fb22

Based on the riscv-go port.

Updates #27532

Change-Id: I3a4d86783fbd625e3ade16d08f87d66e4502f3f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/204660
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fix up the new dead code pass to include support for populating the
ctxt "Reachparent" map, which is needed to support field tracking.
Since we don't have sym.Symbols created at the point where new dead
code runs, keep track of reachability using global symbol indices, and
then once loader.LoadFull is complete we can translate the index
mappings into symbol mappings.

The fieldtracking output is unfortunately different relative to
master, due to differences in the order in which symbols are
encountered in deadcode, but I have eyeballed the results to make sure
they look reasonable.

Change-Id: I48c7a4597f05c00f15af3bfd37fc15ab4d0017c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/204342
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

ABI alias references in Go symbols are resolved during
loadObjFull. But for external symbols they are not resolved. If
there is a reference from an external symbol to a Go ABIInternal
symbol, this reference will be invalid as it is not resolved.

The old code resolve ABI aliases in the deadcode pass. But the
new deadcode pass doesn't do it, as it works with indices instead
of Symbols. We do this in LoadFull.

This makes all internal cgo linking tests pass on Mach-O.

Change-Id: Iac6c084c03f5ddbcc9455527800ce7ed7313f9a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/204698
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>

Updates #35290

Change-Id: I09cad17f09e78c2bf6a9de98b01f13ed383ca006
Reviewed-on: https://go-review.googlesource.com/c/go/+/204643
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

Change-Id: Ie76303e403f0539bdfe14f6bb5f32896df916bce
Reviewed-on: https://go-review.googlesource.com/c/go/+/204657
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

The addAdjustedTimers function was a late addition, and it got some of
the state machine wrong, leading to failures like
https://storage.googleapis.com/go-build-log/930576b6/windows-amd64-2016_53d0319e.log

Updates #6239
Updates #27707

Change-Id: I9e94e563b4698ff3035ce609055ca292b9cab3df
Reviewed-on: https://go-review.googlesource.com/c/go/+/204280
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>

In internal linking mode, we need to process cgo_import_static
directives before loading host objects, because the directive is
to tell the host object loader how to deal with imported symbols.

This should fix linking with old object files. I think there
needs some similar logic for new object files, but I'll leave
that for later.

Change-Id: Icaa286de626ea1876086dbdd015047084c92caf9
Reviewed-on: https://go-review.googlesource.com/c/go/+/204697
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>

Fixes #35291

Change-Id: I11ae367b6e972cd9e7a22bbc2cb23d32f4d72b98
Reviewed-on: https://go-review.googlesource.com/c/go/+/204617
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Fixes #35222

Change-Id: I8be45092ac4079d21ff54661637a3aa8ec4eb9bc
GitHub-Last-Rev: 954a016c9bb749268e97489911ea577a6df9fb4c
GitHub-Pull-Request: golang/go#35298
Reviewed-on: https://go-review.googlesource.com/c/go/+/204601
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

And simplify the remaining rules.

Updates #30439

Change-Id: Ib89dce16b17ae881824178346ed6ab895b79627e
Reviewed-on: https://go-review.googlesource.com/c/go/+/204600
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Change-Id: Ib29e642c56eca96826187f5737d74f8c0430ac3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/204638
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Katie Hockman <katie@golang.org>