Will also fix type aliases.
Fixes#17766.
For #18130.
Change-Id: I9e1584d47128782152e06abd0a30ef423d5c30d2
Reviewed-on: https://go-review.googlesource.com/35732
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
The runtime internal structField interprets name=="" as meaning anonymous,
but the exported reflect.StructField has always set Name, even for anonymous
fields, and also set Anonymous=true.
The initial implementation of StructOf confused the internal and public
meanings of the StructField, expecting the runtime representation of
anonymous fields instead of the exported reflect API representation.
It also did not document this fact, so that users had no way to know how
to create an anonymous field.
This CL changes StructOf to use the previously documented interpretation
of reflect.StructField instead of an undocumented one.
The implementation of StructOf also, in some cases, allowed creating
structs with unexported fields (if you knew how to ask) but set the
PkgPath incorrectly on those fields. Rather than try to fix that, this CL
changes StructOf to reject attempts to create unexported fields.
(I think that may be the right design choice, not just a temporary limitation.
In any event, it's not the topic for today's work.)
For #17766.
Fixes#18780.
Change-Id: I585a4e324dc5a90551f49d21ae04d2de9ea04b6c
Reviewed-on: https://go-review.googlesource.com/35731
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
A Func's Shortname is just an identifier. No need for an entire ONAME
Node.
Change-Id: Ie4d397e8d694c907fdf924ce57bd96bdb4aaabca
Reviewed-on: https://go-review.googlesource.com/35574
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Plus a few minor changes.
For #18130.
Change-Id: Ica6503fe9c888cc05c15b46178423f620c087491
Reviewed-on: https://go-review.googlesource.com/35233
Reviewed-by: Alan Donovan <adonovan@google.com>
Known issue: #18640 (requires a bit more work, I believe).
For #18130.
Change-Id: I53dc26012070e0c79f63b7c76266732190a83d47
Reviewed-on: https://go-review.googlesource.com/35129
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Known issues:
- needs many more tests
- duplicate method declarations via type alias names are not detected
- type alias cycle error messages need to be improved
- need to review setup of byte/rune type aliases
For #18130.
Change-Id: Icc2fefad6214e5e56539a9dcb3fe537bf58029f8
Reviewed-on: https://go-review.googlesource.com/35121
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Also: Don't allow type pragmas with type alias declarations.
For #18130.
Change-Id: Ie54ea5fefcd677ad87ced03466bbfd783771e974
Reviewed-on: https://go-review.googlesource.com/35102
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
cmd/compile:
- remove crud from prior alias implementation
- better comments in places
go/types:
- fix TypeName.IsAlias predicate
- more tests
go/importer (go/internal/gcimporter15):
- handle "@" format for anonymous fields using aliases
(currently tested indirectly via x/tools/gcimporter15 tests)
For #18130.
Change-Id: I23a6d4e3a4c2a5c1ae589513da73fde7cad5f386
Reviewed-on: https://go-review.googlesource.com/35101
Reviewed-by: Alan Donovan <adonovan@google.com>
This defines the (tentative) export/import format for type aliases.
The compiler doesn't support type aliases yet, so while the code is present
it is guarded with a flag.
The export format for embedded (anonymous) fields now has three modes (mode 3 is new):
1) The original type name and the anonymous field name are the same, and the name is exported:
we don't need the field name and write "" instead
2) The original type name and the anonymous field name are the same, and the name is not exported:
we don't need the field name and write "?" instead, indicating that there is package info
3) The original type name and the anonymous field name are different:
we do need the field name and write "@" followed by the field name (and possible package info)
For #18130.
Change-Id: I790dad826757233fa71396a210f966c6256b75d3
Reviewed-on: https://go-review.googlesource.com/35100
Reviewed-by: Alan Donovan <adonovan@google.com>
- added internal isAlias predicated and test
- use it for improved Object printing
- when printing a basic type object, don't repeat type name
(i.e., print "type int" rather than "type int int")
- added another test to testdata/decls4.src
For #18130.
Change-Id: Ice9517c0065a2cc465c6d12f87cd27c01ef801e6
Reviewed-on: https://go-review.googlesource.com/35093
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
Now a TypeName is just that: a name for a type (not just Named and Basic types
as before). If it happens to be an alias, its type won't be a Named or Basic type,
or it won't have the same name. We can determine this externally.
It may be useful to provide a helper predicate to make that test easily accessible,
but we can get to that if there's an actual need.
The field/method lookup code has become more general an simpler, which is a good sign.
The changes in methodset.go are symmetric to the changes in lookup.go.
Known issue: Cycles created via alias types are not properly detected at the moment.
For #18130.
Change-Id: I90a3206be13116f89c221b5ab4d0f577eec6c78a
Reviewed-on: https://go-review.googlesource.com/35091
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
It's earlier than usual but this will help us put the type alias-aware
code into x/tools without breaking clients on go1.6, go1.7,
or (eventually) go1.8.
Change-Id: I43e7ea804922de07d153c7e356cf95e2a11fc592
Reviewed-on: https://go-review.googlesource.com/35050
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Parsing and printing support for type aliases complete.
go/types recognizes them an issues an "unimplemented" error for now.
For #18130.
Change-Id: I9f2f7b1971b527276b698d9347bcd094ef0012ee
Reviewed-on: https://go-review.googlesource.com/34986
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Change-Id: I429637ca91f7db4144f17621de851a548dc1ce76
Reviewed-on: https://go-review.googlesource.com/34923
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Rule 9 arguably doesn't make sense for IPv4 addresses, and so far it
has only caused problems (#13283, #18518). Disable it until we hear
from users that actually want/need it.
Fixes#18518.
Change-Id: I7b0dd75d03819cab8e0cd4c29f0c1dc8d2e9c179
Reviewed-on: https://go-review.googlesource.com/34914
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CALLPART of STRUCTLIT did not check for incomplete initialization
of struct; modify PTRLIT treatment to force zeroing.
Test for structlit, believe this might have also failed for
arraylit.
Fixes#18410.
Change-Id: I511abf8ef850e300996d40568944665714efe1fc
Reviewed-on: https://go-review.googlesource.com/34622
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
To implement the blocking of a select, a goroutine builds a list of
offers to communicate (pseudo-g's, aka sudog), one for each case,
queues them on the corresponding channels, and waits for another
goroutine to complete one of those cases and wake it up. Obviously it
is not OK for two other goroutines to complete multiple cases and both
wake the goroutine blocked in select. To make sure that only one
branch of the select is chosen, all the sudogs contain a pointer to a
shared (single) 'done uint32', which is atomically cas'ed by any
interested goroutines. The goroutine that wins the cas race gets to
wake up the select. A complication is that 'done uint32' is stored on
the stack of the goroutine running the select, and that stack can move
during the select due to stack growth or stack shrinking.
The relevant ordering to block and unblock in select is:
1. Lock all channels.
2. Create list of sudogs and queue sudogs on all channels.
3. Switch to system stack, mark goroutine as asleep,
unlock all channels.
4. Sleep until woken.
5. Wake up on goroutine stack.
6. Lock all channels.
7. Dequeue sudogs from all channels.
8. Free list of sudogs.
9. Unlock all channels.
There are two kinds of stack moves: stack growth and stack shrinking.
Stack growth happens while the original goroutine is running.
Stack shrinking happens asynchronously, during garbage collection.
While a channel listing a sudog is locked by select in this process,
no other goroutine can attempt to complete communication on that
channel, because that other goroutine doesn't hold the lock and can't
find the sudog. If the stack moves while all the channel locks are
held or when the sudogs are not yet or no longer queued in the
channels, no problem, because no goroutine can get to the sudogs and
therefore to selectdone. We only need to worry about the stack (and
'done uint32') moving with the sudogs queued in unlocked channels.
Stack shrinking can happen any time the goroutine is stopped.
That code already acquires all the channel locks before doing the
stack move, so it avoids this problem.
Stack growth can happen essentially any time the original goroutine is
running on its own stack (not the system stack). In the first half of
the select, all the channels are locked before any sudogs are queued,
and the channels are not unlocked until the goroutine has stopped
executing on its own stack and is asleep, so that part is OK. In the
second half of the select, the goroutine wakes up on its own goroutine
stack and immediately locks all channels. But the actual call to lock
might grow the stack, before acquiring any locks. In that case, the
stack is moving with the sudogs queued in unlocked channels. Not good.
One goroutine has already won a cas on the old stack (that goroutine
woke up the selecting goroutine, moving it out of step 4), and the
fact that done = 1 now should prevent any other goroutines from
completing any other select cases. During the stack move, however,
sudog.selectdone is moved from pointing to the old done variable on
the old stack to a new memory location on the new stack. Another
goroutine might observe the moved pointer before the new memory
location has been initialized. If the new memory word happens to be
zero, that goroutine might win a cas on the new location, thinking it
can now complete the select (again). It will then complete a second
communication (reading from or writing to the goroutine stack
incorrectly) and then attempt to wake up the selecting goroutine,
which is already awake.
The scribbling over the goroutine stack unexpectedly is already bad,
but likely to go unnoticed, at least immediately. As for the second
wakeup, there are a variety of ways it might play out.
* The goroutine might not be asleep.
That will produce a runtime crash (throw) like in #17007:
runtime: gp: gp=0xc0422dcb60, goid=2299, gp->atomicstatus=8
runtime: g: g=0xa5cfe0, goid=0, g->atomicstatus=0
fatal error: bad g->status in ready
Here, atomicstatus=8 is copystack; the second, incorrect wakeup is
observing that the selecting goroutine is in state "Gcopystack"
instead of "Gwaiting".
* The goroutine might be sleeping in a send on a nil chan.
If it wakes up, it will crash with 'fatal error: unreachable'.
* The goroutine might be sleeping in a send on a non-nil chan.
If it wakes up, it will crash with 'fatal error: chansend:
spurious wakeup'.
* The goroutine might be sleeping in a receive on a nil chan.
If it wakes up, it will crash with 'fatal error: unreachable'.
* The goroutine might be sleeping in a receive on a non-nil chan.
If it wakes up, it will silently (incorrectly!) continue as if it
received a zero value from a closed channel, leaving a sudog queued on
the channel pointing at that zero vaue on the goroutine's stack; that
space will be reused as the goroutine executes, and when some other
goroutine finally completes the receive, it will do a stray write into
the goroutine's stack memory, which may cause problems. Then it will
attempt the real wakeup of the goroutine, leading recursively to any
of the cases in this list.
* The goroutine might have been running a select in a finalizer
(I hope not!) and might now be sleeping waiting for more things to
finalize. If it wakes up, as long as it goes back to sleep quickly
(before the real GC code tries to wake it), the spurious wakeup does
no harm (but the stack was still scribbled on).
* The goroutine might be sleeping in gcParkAssist.
If it wakes up, that will let the goroutine continue executing a bit
earlier than we would have liked. Eventually the GC will attempt the
real wakeup of the goroutine, leading recursively to any of the cases
in this list.
* The goroutine cannot be sleeping in bgsweep, because the background
sweepers never use select.
* The goroutine might be sleeping in netpollblock.
If it wakes up, it will crash with 'fatal error: netpollblock:
corrupted state'.
* The goroutine might be sleeping in main as another thread crashes.
If it wakes up, it will exit(0) instead of letting the other thread
crash with a non-zero exit status.
* The goroutine cannot be sleeping in forcegchelper,
because forcegchelper never uses select.
* The goroutine might be sleeping in an empty select - select {}.
If it wakes up, it will return to the next line in the program!
* The goroutine might be sleeping in a non-empty select (again).
In this case, it will wake up spuriously, with gp.param == nil (no
reason for wakeup), but that was fortuitously overloaded for handling
wakeup due to a closing channel and the way it is handled is to rerun
the select, which (accidentally) handles the spurious wakeup
correctly:
if cas == nil {
// This can happen if we were woken up by a close().
// TODO: figure that out explicitly so we don't need this loop.
goto loop
}
Before looping, it will dequeue all the sudogs on all the channels
involved, so that no other goroutine will attempt to wake it.
Since the goroutine was blocked in select before, being blocked in
select again when the spurious wakeup arrives may be quite likely.
In this case, the spurious wakeup does no harm (but the stack was
still scribbled on).
* The goroutine might be sleeping in semacquire (mutex slow path).
If it wakes up, that is taken as a signal to try for the semaphore
again, not a signal that the semaphore is now held, but the next
iteration around the loop will queue the sudog a second time, causing
a cycle in the wakeup list for the given address. If that sudog is the
only one in the list, when it is eventually dequeued, it will
(due to the precise way the code is written) leave the sudog on the
queue inactive with the sudog broken. But the sudog will also be in
the free list, and that will eventually cause confusion.
* The goroutine might be sleeping in notifyListWait, for sync.Cond.
If it wakes up, (*Cond).Wait returns. The docs say "Unlike in other
systems, Wait cannot return unless awoken by Broadcast or Signal,"
so the spurious wakeup is incorrect behavior, but most callers do not
depend on that fact. Eventually the condition will happen, attempting
the real wakeup of the goroutine and leading recursively to any of the
cases in this list.
* The goroutine might be sleeping in timeSleep aka time.Sleep.
If it wakes up, it will continue running, leaving a timer ticking.
When that time bomb goes off, it will try to ready the goroutine
again, leading to any one of the cases in this list.
* The goroutine cannot be sleeping in timerproc,
because timerproc never uses select.
* The goroutine might be sleeping in ReadTrace.
If it wakes up, it will print 'runtime: spurious wakeup of trace
reader' and return nil. All future calls to ReadTrace will print
'runtime: ReadTrace called from multiple goroutines simultaneously'.
Eventually, when trace data is available, a true wakeup will be
attempted, leading to any one of the cases in this list.
None of these fatal errors appear in any of the trybot or dashboard
logs. The 'bad g->status in ready' that happens if the goroutine is
running (the most likely scenario anyway) has happened once on the
dashboard and eight times in trybot logs. Of the eight, five were
atomicstatus=8 during net/http tests, so almost certainly this bug.
The other three were atomicstatus=2, all near code in select,
but in a draft CL by Dmitry that was rewriting select and may or may
not have had its own bugs.
This bug has existed since Go 1.4. Until then the select code was
implemented in C, 'done uint32' was a C stack variable 'uint32 done',
and C stacks never moved. I believe it has become more common recently
because of Brad's work to run more and more tests in net/http in
parallel, which lengthens race windows.
The fix is to run step 6 on the system stack,
avoiding possibility of stack growth.
Fixes#17007 and possibly other mysterious failures.
Change-Id: I9d6575a51ac96ae9d67ec24da670426a4a45a317
Reviewed-on: https://go-review.googlesource.com/34835
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
This adds high-level descriptions of the scheduler structures, the
user and system stacks, error handling, and synchronization.
Change-Id: I1eed97c6dd4a6e3d351279e967b11c6e64898356
Reviewed-on: https://go-review.googlesource.com/34290
Reviewed-by: Rick Hudson <rlh@golang.org>
The comment describing the overall GC algorithm at the top of mgc.go
has gotten woefully out-of-date (and was possibly never
correct/complete). Update it to reflect the current workings of the
GC and the set of phases that we now divide it into.
Change-Id: I02143c0ebefe9d4cd7753349dab8045f0973bf95
Reviewed-on: https://go-review.googlesource.com/34711
Reviewed-by: Rick Hudson <rlh@golang.org>
If one of the c.Get(ts.URL) results in an error, the child goroutine
calls t.Errorf, but the test goroutine gets stuck waiting for <-gotReqCh,
so the test hangs and the program is eventually killed (after 10 minutes!).
Whatever might have been printed to t.Errorf is never seen.
Adjust test so that the test fails cleanly in this case.
Still trying to debug why c.Get might fail.
It seems to have something to do with occasional connection
failures on macOS Sierra.
Change-Id: Ia797787bd51ea7cd6deb1192aec89c331c4f2c48
Reviewed-on: https://go-review.googlesource.com/34836
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Currently, the check for legal pointers in stack copying uses
_PageSize (8K) as the minimum legal pointer. By default, Linux won't
let you map under 64K, but
1) it's less clear what other OSes allow or will allow in the future;
2) while mapping the first page is a terrible idea, mapping anywhere
above that is arguably more justifiable;
3) the compiler only assumes the first physical page (4K) is never
mapped.
Make the runtime consistent with the compiler and more robust by
changing the bad pointer check to use 4K as the minimum legal pointer.
This came out of discussions on CLs 34663 and 34719.
Change-Id: Idf721a788bd9699fb348f47bdd083cf8fa8bd3e5
Reviewed-on: https://go-review.googlesource.com/34890
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
We cannot assume that the platform running documentation service is
the target platform.
Change-Id: I241ed6f8778169faac9ef49e11dcd40f7422cccc
Reviewed-on: https://go-review.googlesource.com/34750
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Fixes#18392.
Avoid nil dereferencing n.Right when dealing with non-existent
self referenced interface methods e.g.
type A interface{
Fn(A.Fn)
}
Instead, infer the symbol name from n.Sym itself.
Change-Id: I60d5f8988e7318693e5c8da031285d8d7347b771
Reviewed-on: https://go-review.googlesource.com/34817
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This change uses runtime.support_bmi2 as an additional condition
to examine the usability of AVX2 version algorithm, fixes
the crash on the platfrom which supports AVX2 but not support BMI2.
Fixes#18512
Change-Id: I408c0844ae2eb242dacf70cb9e8cec1b8f3bd941
Reviewed-on: https://go-review.googlesource.com/34851
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The existing implementations on AMD64 only detects AVX2 usability,
when they also contains BMI (bit-manipulation instructions).
These instructions crash the running program as 'unknown instructions'
on the architecture, e.g. i3-4000M, which supports AVX2 but not
support BMI.
This change added the detections for BMI1 and BMI2 to AMD64 runtime with
two flags as the result, `support_bmi1` and `support_bmi2`,
in runtime/runtime2.go. It also completed the condition to run AVX2 version
in packages crypto/sha1 and crypto/sha256.
Fixes#18512
Change-Id: I917bf0de365237740999de3e049d2e8f2a4385ad
Reviewed-on: https://go-review.googlesource.com/34850
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Fixes#18447
Change-Id: I5d60c3632a5ce625d3bac9d85533ce689e301707
Reviewed-on: https://go-review.googlesource.com/34813
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
No test because in practice these errors never occur.
Change-Id: I11c77893ae931fc621c98920cba656790d18ed93
Reviewed-on: https://go-review.googlesource.com/34811
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Android on ChromeOS uses a restrictive seccomp filter that blocks
sched_getaffinity, leading this code to index a slice by -errno.
Change-Id: Iec09a4f79dfbc17884e24f39bcfdad305de75b37
Reviewed-on: https://go-review.googlesource.com/34794
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Given
var t struct{ lock sync.Mutex }
var fntab []func(t)
f(a(), b(&t), c(), fntab[0](t))
Before:
function call copies lock value: struct{lock sync.Mutex} contains sync.Mutex
After:
call of fntab[0] copies lock value: struct{lock sync.Mutex} contains sync.Mutex
This will make diagnosis easier when there are multiple function calls per line.
Change-Id: I9881713c5671b847b84a0df0115f57e7cba17d72
Reviewed-on: https://go-review.googlesource.com/34730
Reviewed-by: Ian Lance Taylor <iant@golang.org>
