This change moves the responsibility of throwing if an mcache is not
available to the caller, because the inlining cost of throw is set very
high in the compiler. Even if it was reduced down to the cost of a usual
function call, it would still be too expensive, so just move it out.
This choice also makes sense in the context of #42339 since we're going
to have to handle the case where we don't have an mcache to update stats
in a few contexts anyhow.
Also, add getMCache to the list of functions that should be inlined to
prevent future regressions.
getMCache is called on the allocation fast path and because its not
inlined actually causes a significant regression (~10%) in some
microbenchmarks.
Fixes#42305.
Change-Id: I64ac5e4f26b730bd4435ea1069a4a50f55411ced
Reviewed-on: https://go-review.googlesource.com/c/go/+/267157
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
This is a roll-forward of golang.org/cl/262618, which was reverted in
golang.org/cl/267037. The only differences between this CL and the
original are the three calls to fflush from the C files in
build_overlay.txt, to guarantee that the string we're expecting is
actually written out.
This requires rewriting the paths of the files passed to the cgo tool
toolchain to use the overlaid paths instead of the disk paths of
files. Because the directories of the overlaid paths don't exist in
general, the cgo tool have been updated to run in base.Cwd instead of
the package directory.
For #39958
Change-Id: If7e5e057c62c0c22ddb724f9fe650902fc5f4832
Reviewed-on: https://go-review.googlesource.com/c/go/+/267197
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Trust: Michael Matloob <matloob@golang.org>
In Go 1.12, we changed the runtime to use MADV_FREE when available on
Linux (falling back to MADV_DONTNEED) in CL 135395 to address issue
#23687. While MADV_FREE is somewhat faster than MADV_DONTNEED, it
doesn't affect many of the statistics that MADV_DONTNEED does until
the memory is actually reclaimed under OS memory pressure. This
generally leads to poor user experience, like confusing stats in top
and other monitoring tools; and bad integration with management
systems that respond to memory usage.
We've seen numerous issues about this user experience, including
#41818, #39295, #37585, #33376, and #30904, many questions on Go
mailing lists, and requests for mechanisms to change this behavior at
run-time, such as #40870. There are also issues that may be a result
of this, but root-causing it can be difficult, such as #41444 and
#39174. And there's some evidence it may even be incompatible with
Android's process management in #37569.
This CL changes the default to prefer MADV_DONTNEED over MADV_FREE, to
favor user-friendliness and minimal surprise over performance. I think
it's become clear that Linux's implementation of MADV_FREE ultimately
doesn't meet our needs. We've also made many improvements to the
scavenger since Go 1.12. In particular, it is now far more prompt and
it is self-paced, so it will simply trickle memory back to the system
a little more slowly with this change. This can still be overridden by
setting GODEBUG=madvdontneed=0.
Fixes#42330 (meta-issue).
Fixes#41818, #39295, #37585, #33376, #30904 (many of which were
already closed as "working as intended").
Change-Id: Ib6aa7f2dc8419b32516cc5a5fc402faf576c92e4
Reviewed-on: https://go-review.googlesource.com/c/go/+/267100
Trust: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Steps run:
$ cd $(go env GOROOT)/src
$ go get -d golang.org/x/sys
$ go mod tidy
$ go mod vendor
$ go generate syscall/... internal/syscall/...
$ cd cmd
$ go get -d golang.org/x/sys
$ go mod tidy
$ go mod vendor
$ cd ..
$ git add .
This change subsumes CL 260860.
For #36905
Change-Id: I7c677c6aa1ad61b9cbd8cf9ed208ed5a30f29c87
Reviewed-on: https://go-review.googlesource.com/c/go/+/267103
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Minor optimization. Spotted while working on that code.
Change-Id: Ia02dee10d74bce79a0bef1eaba7fac1bfc27df38
Reviewed-on: https://go-review.googlesource.com/c/go/+/266899
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: fannie zhang <Fannie.Zhang@arm.com>
Reviewed-by: David Chase <drchase@google.com>
Adjust mksyscall_windows.go to activate module mode and set
-mod=readonly, and to suppress its own deprecation warning when run
from within GOROOT/src.
We can't vendor the mkwinsyscall tool in to the std module directly,
because std-vendored dependencies (unlike the dependencies of all
other modules) turn into actual, distinct packages in 'std' when
viewed from outside the 'std' module. We don't want to introduce a
binary in the 'std' meta-pattern, but we also don't particularly want
to add more special-cases to the 'go' command right now when we have
an existing wrapper program that can do the job.
I also regenerated the affected packages to ensure that they are
consistent with the current version of mksyscall, which produced some
declaration-order changes in
internal/syscall/windows/zsyscall_windows.go.
Fixes#41916
Updates #25922
Change-Id: If6e6f8ba3dd372a7ecd6820ee6c0ca38d55f0f35
Reviewed-on: https://go-review.googlesource.com/c/go/+/261499
Trust: Bryan C. Mills <bcmills@google.com>
Trust: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
This results in a nicer error message if the argument to Go.run is
omitted or of the wrong type.
Fixes#37000
Change-Id: I7f36d007f41a79b2cea1cebf5cce127786341202
Reviewed-on: https://go-review.googlesource.com/c/go/+/266117
Trust: Richard Musiol <neelance@gmail.com>
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Proof of concept; also an actual optimization that fires 180 times
in the Go source base.
Change-Id: I5cb87474be764264cde6e4cbcb471ef109306f08
Reviewed-on: https://go-review.googlesource.com/c/go/+/248404
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
We already remove racefuncenter and racefuncexit if they are not
needed (i.e. the function doesn't have any other race calls).
racefuncenterfp is like racefuncenter but used on LR machines.
Remove unnecessary racefuncenterfp as well.
Change-Id: I65edb00e19c6d9ab55a204cbbb93e9fb710559f1
Reviewed-on: https://go-review.googlesource.com/c/go/+/267099
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
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Reviewed-by: David Chase <drchase@google.com>
Optimize small (s <= 32) zeroing/moving operations on riscv64.
Avoid generating unaligned memory accesses.
The code is almost one to one translation of the corresponding
mips64 rules with additional rule for s=32.
Change-Id: I753b0b8e53cb9efcf43c8080cab90f3d03539fb8
Reviewed-on: https://go-review.googlesource.com/c/go/+/266217
Reviewed-by: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Add "go/analysis/passes/testinggoroutine" from x/tools and vendor its source in.
This pass will catch misuses of:
* testing.T.Fail*
* testing.T.Fatal*
* testing.T.Skip*
inside goroutines explicitly started by the go keyword.
The pass was implemented in CL 212920.
While here, found 2 misuses in:
* database/sql/sql_test.go
* runtime/syscall_windows_test.go
and fixed them in CL 235527.
Fixes#5746
Change-Id: I1740ad3f1d677bb5d78dc5d8d66bac6ec287a2b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/235677
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
In golang.org/cl/266199, I reused the existing code in inlining that
recognizes anonymous variables. However, it turns out that code
mistakenly recognizes anonymous return parameters as named when
inlining a function from the same package.
The issue is funcargs (which is only used for functions parsed from
source) synthesizes ~r names for anonymous return parameters, but
funcargs2 (which is only used for functions imported from export data)
does not.
This CL fixes the behavior so that anonymous return parameters are
handled identically whether a function is inlined within the same
package or across packages. It also adds a proper cross-package test
case demonstrating #33160 is fixed in both cases.
Change-Id: Iaa39a23f5666979a1f5ca6d09fc8c398e55b784c
Reviewed-on: https://go-review.googlesource.com/c/go/+/266719
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
Trust: Matthew Dempsky <mdempsky@google.com>
Found by go vet pass "testinggoroutines".
Change-Id: I6360af2079617b7aa62dcb9bd7254578ca5d1c1d
Reviewed-on: https://go-review.googlesource.com/c/go/+/235527
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Emmanuel Odeke <emmanuel@orijtech.com>
(*Process).Signal returns an error sentinel, previously errFinished,
when (*Process).done or syscall.ESRCH. Callers would like the ability to
test for this state, so the value has been exported as ErrProcessDone.
Fixes#39444
Change-Id: I510e7647cc032af290180de5149f35ab7b09a526
Reviewed-on: https://go-review.googlesource.com/c/go/+/242998
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Sign extension for consts is unnecessary and zero extension for consts can be avoided
via casts. This removes over 16,000 instructions from the Go binary, in part because it
allows for better zero const absorbtion in blocks - for example,
`(BEQ (MOVBU (MOVBconst [0])) cond yes no)` now becomes `(BEQZ cond yes no)` when
this change is combined with existing rules.
Change-Id: I27e791bfa84869639db653af6119f6e10369ba3d
Reviewed-on: https://go-review.googlesource.com/c/go/+/265041
Trust: Joel Sing <joel@sing.id.au>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
This requires rewriting the paths of the files passed to the cgo tool
toolchain to use the overlaid paths instead of the disk paths of
files. Because the directories of the overlaid paths don't exist in
general, the cgo tool have been updated to run in base.Cwd instead of
the package directory.
For #39958
Change-Id: I8986de889f56ecc2e64fa69f5f6f29fa907408f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/262618
Trust: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
cmd/cgo now has a -trimpath flag that behaves the same as the
-trimpath flag to cmd/compile. This will be used to correct paths
to cgo files that are overlaid.
The code that processes trimpath in internal/objapi has been slightly
refactored because it's currently only accessible via AbsFile, which
does some additional processing to the path names. Now an
ApplyRewrites function is exported that just applies the trimpath
rewrites.
Also remove unused srcfile argument to cmd/cgo.(*Package).godefs.
For #39958
Change-Id: I497d48d0bc2fe1f6ab2b5835cbe79f15b839ee59
Reviewed-on: https://go-review.googlesource.com/c/go/+/266358
Trust: Michael Matloob <matloob@golang.org>
Run-TryBot: Michael Matloob <matloob@golang.org>
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Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Changed fmt.go to print out some extra information for various kinds of
Nodes. This includes some extra (small) info in the %j (jconv) output,
and some missing sections (such as Dcls and the body of a closure) in
nodedump().
Also, added some extra doc comments for a few Node types in syntax.go
Change-Id: I2ec7184e2abe0d5fbe3fb5a2506da7c7b06f2fb1
Reviewed-on: https://go-review.googlesource.com/c/go/+/266437
Run-TryBot: Dan Scales <danscales@google.com>
Trust: Dan Scales <danscales@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Currently worldsema is not released with direct handoff, so the
semaphore is an unfair synchronization mechanism. If, for example,
ReadMemStats is called in a loop, it can continuously stomp on attempts
by the GC to stop the world.
Note that it's specifically possible for ReadMemStats to delay a STW to
end GC since ReadMemStats is able to STW during a GC since #19112 was
fixed.
While this particular case is unlikely and the right answer in most
applications is to simply not call such an expensive operation in a
loop, this pattern is used often in tests.
Fixes#40459.
Change-Id: Ia4a54f0fd956ea145a319f9f06c4cd37dd52fd8a
Reviewed-on: https://go-review.googlesource.com/c/go/+/243977
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: David Chase <drchase@google.com>
Make them always true. Delete code that are only executed when
they are false.
Change-Id: I6194fa00de23486c2b0a0c9075fe3a09d9c52762
Reviewed-on: https://go-review.googlesource.com/c/go/+/264339
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@google.com>
We use systemstack on the locking path to avoid stack splits which could
cause locks to be recorded out of order (see comment on lockWithRank).
This concern is irrelevant on lock assertions, where we simply need to
see if a lock is held and don't care if another is taken in the
meantime. Thus we can simply drop these unless we actually need to
crash.
Updates #40677
Change-Id: I85d730913a59867753ee1ed0386f8c5efda5c432
Reviewed-on: https://go-review.googlesource.com/c/go/+/266718
Run-TryBot: Michael Pratt <mpratt@google.com>
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Reviewed-by: Austin Clements <austin@google.com>
Trust: Michael Pratt <mpratt@google.com>
In golang.org/cl/264477, I missed this new block after rebasing past
golang.org/cl/232298. These fields must be zero if there are no timers.
Updates #28808
Updates #18237
Change-Id: I2d9e1cbf326497c833daa26b11aed9a1e12c2270
Reviewed-on: https://go-review.googlesource.com/c/go/+/266367
Run-TryBot: Michael Pratt <mpratt@google.com>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Michael Pratt <mpratt@google.com>
Some functions that required holding the heap lock _or_ world stop have
been simplified to simply requiring the heap lock. This is conceptually
simpler and taking the heap lock during world stop is guaranteed to not
contend. This was only done on functions already called on the
systemstack to avoid too many extra systemstack calls in GC.
Updates #40677
Change-Id: I15aa1dadcdd1a81aac3d2a9ecad6e7d0377befdc
Reviewed-on: https://go-review.googlesource.com/c/go/+/250262
Run-TryBot: Michael Pratt <mpratt@google.com>
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Reviewed-by: Austin Clements <austin@google.com>
Trust: Michael Pratt <mpratt@google.com>
Stopping the world is an implicit lock for many operations, so we should
assert the world is stopped in functions that require it.
This is enabled along with the rest of lock ranking, though it is a bit
orthogonal and likely cheap enough to enable all the time should we
choose.
Requiring a lock _or_ world stop is common, so that can be expressed as
well.
Updates #40677
Change-Id: If0a58544f4251d367f73c4120c9d39974c6cd091
Reviewed-on: https://go-review.googlesource.com/c/go/+/248577
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Trust: Michael Pratt <mpratt@google.com>
Change-Id: Ibf68e663f29a5cb3b64a7d923c005c16da647769
Reviewed-on: https://go-review.googlesource.com/c/go/+/266537
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
reassignVisitor was short-circuiting on assignment statements after
checking the LHS, but there might be further assignment statements
nested within the RHS expressions.
Fixes#42284.
Change-Id: I175eef87513b973ed5ebe6a6527adb9766dde6cf
Reviewed-on: https://go-review.googlesource.com/c/go/+/266618
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
https://reviews.llvm.org/D90435 is the counterpart in LLVM TSAN.
race_linux_arm64.syso is built with LLVM commit
00da38ce2d36c07f12c287dc515d37bb7bc410e9 on a macOS/ARM64 machine.
(It is not built on a builder with golang.org/x/build/cmd/racebuild
as we don't have darwin/arm64 builder for now.)
Updates #38485.
Change-Id: I391efdacd9480197e308370bfccd05777deb4aee
Reviewed-on: https://go-review.googlesource.com/c/go/+/266373
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Previous is used during downgrading. If the module proxy does not
advertise any versions (for example, because it contains only
pseudo-versions), then Previous should return "none" instead of a
non-nil error.
For #37438
Change-Id: I4edfec19cfeb3ffe50df4979f99a01321c442509
Reviewed-on: https://go-review.googlesource.com/c/go/+/266370
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
I find it pretty difficult to reason about test-dependency modules
when they aren't in the same file as the rest of the test.
Now that 'go get' supports replacements (CL 258220 and CL 266018),
we can localize tests that need 'go get' but don't specifically depend
on module proxy semantics.
For #36460
For #37438
Change-Id: Ib37a6c170f251435399dfc23e60d96681a81eadc
Reviewed-on: https://go-review.googlesource.com/c/go/+/266369
Trust: Bryan C. Mills <bcmills@google.com>
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Reviewed-by: Michael Matloob <matloob@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
For #37438
Change-Id: I2e1f47d567842ac5504b7b8ed0b3fba6f92d778b
Reviewed-on: https://go-review.googlesource.com/c/go/+/266340
Run-TryBot: Bryan C. Mills <bcmills@google.com>
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Reviewed-by: Michael Matloob <matloob@golang.org>
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Trust: Bryan C. Mills <bcmills@google.com>
For #37438
Change-Id: Icb28035ae4027aa09d8959d4ac2f4b94a6c843a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/266339
Run-TryBot: Bryan C. Mills <bcmills@google.com>
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This patch changes the way the linker emits the DWARF line table
prologue, specifically the file table. Previously files were left
unmodified, and the directory table was empty. For each compilation
unit we now scan the unit file table and build up a common set of
directories, emit them into the directory table, and then emit file
entries that refer to the dirs. This provides a modest binary size
savings.
For kubernetes kubelet:
$ objdump -h /tmp/kubelet.old | fgrep debug_line
36 .zdebug_line 019a55f5 0000000000000000 0000000000000000 084a5123 2**0
$ objdump -h /tmp/kubelet.new | fgrep debug_line
36 .zdebug_line 01146fd2 0000000000000000 0000000000000000 084a510a 2**0
[where the value following the section name above is the section size
in hex, so roughly a 30% decrease in this case.]
The actual savings will depend on the length of the pathnames
involved, so it's hard to really pin down how much savings we'll see
here. In addition, emitting the files this way reduces the
"compressibility" of the line table, so there could even be cases
where we don't win at all.
Updates #6853, #19784, #36495.
Change-Id: I298d8561da5ed3ebc9d38aa772874851baa2f4f4
Reviewed-on: https://go-review.googlesource.com/c/go/+/263017
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Trust: Than McIntosh <thanm@google.com>
Also use the simplified nobarrierWakeTime in findrunnable, as it no
longer needs the current time.
Change-Id: I77b125d6a184dde0aeb517fc068164c274f0a046
Reviewed-on: https://go-review.googlesource.com/c/go/+/266304
Trust: Ian Lance Taylor <iant@golang.org>
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Reviewed-by: Michael Pratt <mpratt@google.com>
[This is a roll-forward of CL 262319, with a fix for some Darwin test
failures].
Change the definitions of selected runtime assembly routines
from ABI0 (the default) to ABIInternal. The ABIInternal def is
intended to indicate that these functions don't follow the existing Go
runtime ABI. In addition, convert the assembly reference to
runtime.main (from runtime.mainPC) to ABIInternal. Finally, for
functions such as "runtime.duffzero" that are called directly from
generated code, make sure that the compiler looks up the correct
ABI version.
This is intended to support the register abi work, however these
changes should not have any issues even when GOEXPERIMENT=regabi is
not in effect.
Updates #27539, #40724.
Change-Id: Idf507f1c06176073563845239e1a54dad51a9ea9
Reviewed-on: https://go-review.googlesource.com/c/go/+/266638
Trust: Than McIntosh <thanm@google.com>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Change-Id: Ib833954e8400a63624359a81f5196ca9080199a3
Reviewed-on: https://go-review.googlesource.com/c/go/+/266081
Trust: Alberto Donizetti <alb.donizetti@gmail.com>
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
In CL 264179, some reorganization of error codes was deferred in order
to minimize diffs between patch-sets.
This CL reorganizes the error codes as discussed. It is a pure
reordering, with no material changes other than the changing of internal
const values.
For #42290
Change-Id: I0e9b421a92e96b19e53039652f8de898c5255290
Reviewed-on: https://go-review.googlesource.com/c/go/+/266637
Run-TryBot: Robert Findley <rfindley@google.com>
Trust: Robert Findley <rfindley@google.com>
Trust: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
In the current (pre-CL) version of the spec, the 2nd last shift
example appears to be using the array declared in the last example.
On a 32-bit platform, that array would have length 0, which would
lead to a panic in the 2nd last example. Also, if this code were
inside a function, it wouldn't compile (array declared after use).
Use an explicitly declared array for that specific shift example.
Also, split out all cases that produce different results for 32-
vs 64-bit ints.
Fixes#41835.
Change-Id: Ie45114224509e4999197226f91f7f6f934449abb
Reviewed-on: https://go-review.googlesource.com/c/go/+/260398
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
gcBgMarkWorker G's are primarily scheduled by findRunnableGCWorker, but
that no longer needs to be strictly enforced. Temporary preemption to a
runq is fine when the P is not in use.
We still releasem in gopark in the normal case for efficiency: if
gcDrain stops because gp.preempt is set, then gopark would always
preempt. That is fine, but inefficient, since it will reschedule simply
to park again. Thus, we keep releasem in unlockf to skip this extra
cycle.
Change-Id: I6d1a42e3ca41b76227142a6b5bfb376c9213e3c9
Reviewed-on: https://go-review.googlesource.com/c/go/+/262349
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Trust: Michael Pratt <mpratt@google.com>
Background mark workers perform per-P marking work. Currently each
worker is assigned a P at creation time. The worker "attaches" to the P
via p.gcBgMarkWorker, making itself (usually) available to
findRunnableGCWorker for scheduling GC work.
While running gcMarkDone, the worker "detaches" from the P (by clearing
p.gcBgMarkWorker), since it may park for other reasons and should not be
scheduled by findRunnableGCWorker.
Unfortunately, this design is complex and difficult to reason about. We
simplify things by changing the design to eliminate the hard P
attachment. Rather than workers always performing work from the same P,
workers perform work for whichever P they find themselves on. On park,
the workers are placed in a pool of free workers, which each P's
findRunnableGCWorker can use to run a worker for its P.
Now if a worker parks in gcMarkDone, a P may simply use another worker
from the pool to complete its own work.
The P's GC worker mode is used to communicate the mode to run to the
selected worker. It is also used to emit the appropriate worker
EvGoStart tracepoint. This is a slight change, as this G may be
preempted (e.g., in gcMarkDone). When it is rescheduled, the trace
viewer will show it as a normal goroutine again. It is currently a bit
difficult to connect to the original worker tracepoint, as the viewer
does not display the goid for the original worker (though the data is in
the trace file).
Change-Id: Id7bd3a364dc18a4d2b1c99c4dc4810fae1293c1b
Reviewed-on: https://go-review.googlesource.com/c/go/+/262348
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Trust: Michael Pratt <mpratt@google.com>
Tools using go/types sometimes need to implement special handling for
certain errors produced by the type-checker. They can offer suggested
fixes, expand the error position to surrounding syntax, highlight
related syntax (for example in the case of a declaration cycle), link to
additional documentation, group errors by category, or correlate errors
with signals produced by other static analysis tools.
All these require a notion of error identity. Tools need to be able to
reliably determine the nature of an error without re-implementing type
checking logic or parsing error messages. This CL is a first-pass at
adding such an identifier to types.Error: a (for the moment unexported)
field containing one of many declared errorCode constants.
A wide variety of error code constants are defined, and assigned to type
checker errors according to their 'functional equivalence', meaning that
they should be ideally be stable under refactoring.
With few exceptions, each error code is documented with an example that
produces it. This is enforced by tests.
When error codes are exported they will represent quite a large API
surface. For this reason, as well as the likelihood that error codes
will change at the start, both the code field and the codes themselves
are initially unexported. gopls will read these fields using reflection
during this experimental phase. Others can obviously do the same,
provided they accept the lack of forward compatibility.
For #42290
Change-Id: I15e3c2bffd2046c20297b1857057d421f633098a
Reviewed-on: https://go-review.googlesource.com/c/go/+/264179
Run-TryBot: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Trust: Robert Griesemer <gri@golang.org>
Trust: Robert Findley <rfindley@google.com>
Currently, on all supported platforms, the race detector (LLVM
TSAN) expects the Go heap is at 0xc000000000 - 0xe000000000.
Move the raceenabled condition first, so we always allocate
there.
This means on Linux/ARM64 when race detector is on we will
allocate to 0xc000000000 - 0xe000000000, instead of 0x4000000000.
The old address is meant for 39-bit VMA. But the race detector
only supports 48-bit VMA anyway. So this is fine.
Change-Id: I51ac8eff68297b37c8c651a93145cc94f83a939d
Reviewed-on: https://go-review.googlesource.com/c/go/+/266372
Trust: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
