If a pointer write is not atomic, if the GC is running
concurrently, it may observe a partially updated pointer, which
may point to unallocated or already dead memory. Most pointer
writes, like the store instructions generated by the compiler,
are already atomic. But we still need to be careful in places
like memmove. In memmove, we don't know which bits are pointers
(or too expensive to query), so we ensure that all aligned
pointer-sized units are written atomically.
Fixes#36101.
Change-Id: I1b3ca24c6b1ac8a8aaf9ee470115e9a89ec1b00b
Reviewed-on: https://go-review.googlesource.com/c/go/+/212626
Reviewed-by: Austin Clements <austin@google.com>
When a goroutine yields the remainder of its time to another goroutine
during direct semaphore handoff (as in an Unlock of a sync.Mutex in
starvation mode), it needs to signal that change to the execution
tracer. The discussion in CL 200577 didn't reach consensus on how best
to describe that, but pointed out that "traceEvGoSched / goroutine calls
Gosched" could be confusing.
Emit a "traceEvGoPreempt / goroutine is preempted" event in this case,
to allow the execution tracer to find a consistent event ordering
without being both specific and inaccurate about why the active
goroutine has changed.
Fixes#36186
Change-Id: Ic4ade19325126db2599aff6aba7cba028bb0bee9
Reviewed-on: https://go-review.googlesource.com/c/go/+/211797
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Starting with 2014 (golang.org/cl/46660043), we have enjoyed 6
consecutive years of the gopher. Now, the slice¹ of gophers is
ready to make its way into the next decade, as 2020 is the new
Year of the Gopher.
¹ https://en.wikipedia.org/w/index.php?title=List_of_English_terms_of_venery,_by_animal&oldid=932675028#G
Change-Id: I5f9598dbedb373bd13021964193fa9e44c67693e
Reviewed-on: https://go-review.googlesource.com/c/go/+/213017
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: David Symonds <dsymonds@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Use the libc fcntl (via syscall.fcntl) on aix and solaris like it is
already done for darwin.
For the syscall-based fcntl implementation use FcntlSyscall from
internal/syscall/unix in order to get fcntl64 on 32-bit Linux
systems.
On aix, fcntl with F_DUPFD_CLOEXEC is not supported. Thus, defined
F_DUPFD_CLOEXEC = 0 in the syscall package and check its value before
calling fcntl(fd, syscall.F_DUPFD_CLOEXEC, 0).
On js/wasm, fcntl is not supported thus let its implementation return
ENOSYS directly.
Updates #36211
Change-Id: I96a2ea79e5c4eed2fefd94d0aefd72c940825682
Reviewed-on: https://go-review.googlesource.com/c/go/+/212278
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
On aix and solaris (like on darwin) use libc fcntl to implement
IsNonblock instead of Syscall(SYS_FCNTL, ...) which isn't supported.
Change-Id: I989b02aa0c90b7e2dae025572867dda277fef8be
Reviewed-on: https://go-review.googlesource.com/c/go/+/212600
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Use fcntl64Syscall in forkAndExecInChild1 to get fcntl64 on 32-bit Linux
systems.
Updates #36211
Change-Id: Id0e34359256beace970e72102fdace7a987ff2b0
Reviewed-on: https://go-review.googlesource.com/c/go/+/212598
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Add some new utility functions for decoding "type.*" symbol data
using loader.Sym instead of sym.Symbol. These are needed for DWARF
type DIE generation.
Change-Id: I9a4f81d9c8ea975569ea9a9920d728f1e37d1d15
Reviewed-on: https://go-review.googlesource.com/c/go/+/208229
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Relocate the various new functions for decoding type.* symbol payloads
(using new loader interfaces) to a new file, as opposed to having them
tacked onto the end of deadcode2.go.
Change-Id: I830a8d1b63d70d5bcbc213f2388d00e12f009a77
Reviewed-on: https://go-review.googlesource.com/c/go/+/211305
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Add a Link method that takes a loader sym index instead
of a sym.Symbol.
Change-Id: If59e246cb1adc9066080f019be135387fc1b2fcd
Reviewed-on: https://go-review.googlesource.com/c/go/+/208228
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Add SymbolBuilder helper type -- this type provides a set of methods
intended to make it easy to manipulate the content of a symbol (type,
relocations, data, etc).
Change-Id: I579bf8d04650e66d33a9780a6c2347a576c94c6f
Reviewed-on: https://go-review.googlesource.com/c/go/+/210178
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add a loader method to retrieve the version from a loader.Sym
(useful mainly for debugging at the moment).
Change-Id: I82e0e316bb86eb41b9cf366e656a0f848cf3424e
Reviewed-on: https://go-review.googlesource.com/c/go/+/212617
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This change makes it so that we check whether scavAddr is actually
mapped before trying to look at the summary for the fast path, since we
may segfault if that that part of the summary is not mapped in.
Previously this wasn't a problem because we would conservatively map
all memory for the summaries between the lowest mapped heap address and
the highest one.
This change also adds a test for this case.
Change-Id: I2b1d89b5e044dce81745964dfaba829f4becdc57
Reviewed-on: https://go-review.googlesource.com/c/go/+/212637
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This change disables pageAlloc tests on OpenBSD in short mode because
pageAlloc holds relatively large virtual memory reservations and we make
two during the pageAlloc tests. The runtime may also be carrying one
such reservation making the virtual memory requirement for testing the
Go runtime three times as much as just running a Go binary.
This causes problems for folks who just want to build and test Go
(all.bash) on OpenBSD but either don't have machines with at least 4ish
GiB of RAM (per-process virtual memory limits are capped at some
constant factor times the amount of physical memory) or their
per-process virtual memory limits are low for other reasons.
Fixes#36210.
Change-Id: I8d89cfde448d4cd2fefff4ad6ffed90de63dd527
Reviewed-on: https://go-review.googlesource.com/c/go/+/212177
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Use FcntlSyscall from internal/syscall/unix to get fcntl64 on 32-bit
Linux systems.
Updates #36211
Change-Id: If48a6e09606ca9f7f6e22f3e8dc9a25fb3ccaf65
Reviewed-on: https://go-review.googlesource.com/c/go/+/212537
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Package name and documentation link were wrong.
Change-Id: I274906afc3cf7a3d88e3da76549cd6ab008fd0c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/212538
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Also provide REG_LR to more clearly define the link register.
Based on the riscv-go port.
Updates #27532
Change-Id: I0805f373682f93b3918a01c21d4ef34eb3817c75
Reviewed-on: https://go-review.googlesource.com/c/go/+/204627
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Patch up runtime testing to use the libc fcntl function on Darwin,
which is what we should be doing anyhow. This is similar to how
we handle fcntl on AIX and Solaris.
Fixes#36211
Change-Id: I47ad87e11df043ce21496a0d59523dad28960f76
Reviewed-on: https://go-review.googlesource.com/c/go/+/212299
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
The doc for testing.T and testing.B said that both test and benchmark
logs are printed to stderr, but in reality that wasn't the case.
CL 24311 fixed the doc for T, this change fixes it for B.
Fixes#36257
Change-Id: I0ff77ff44608f60320a1565b371c81e96039e71c
Reviewed-on: https://go-review.googlesource.com/c/go/+/212457
Reviewed-by: Gabriel Aszalos <gabriel.aszalos@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Gabriel Aszalos <gabriel.aszalos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is based on reading through every commit message to runtime and
cmd/{compile,link,internal,asm} since Go 1.13.
Change-Id: I253b1a70ed265f15180fa20c191ceeafa6612ac4
Reviewed-on: https://go-review.googlesource.com/c/go/+/211977
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This patch fixes a couple of bugs introduced in CL 210778 and CL 207606:
- apply the same version selection scheme in loader.CreateExtSym that
we're currently using for loader.Create (since the two functions
will be used in the same way by the host object loader)
- add code to the loader's NewLoader function to create initial map
values for some of the map-based symbol attributes (somewhere along
the line the code to do this seems to have gotten lost, so this
patch adds it back).
- fix a coding error in growAttrBitmaps (wrong bitmap passed to
append when extending attrOnList)
Change-Id: Ie0c8c6876428bb21d788c19a7a2db945ac649fac
Reviewed-on: https://go-review.googlesource.com/c/go/+/212097
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Add new methods to get/set the "dynimplib", "dynimpvers" and
"localentry" attributes for an external Sym in loader.Loader. These
attribute values are stored sparsely, since we expect that most
symbols will not need them; they are set when processing cgo
directives and when dealing with host object symbols.
Change-Id: If0b3c173307801d39cb576bb99c83b9081c42d9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/211298
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add a mechanism for recording symbol alignment for external symbols
under the new loader scheme. Alignments is stored in a side table,
since most symbols don't wind up needing an alignment other than zero.
Change-Id: I97092481412c15eac9b9f4c29b5c273f53759562
Reviewed-on: https://go-review.googlesource.com/c/go/+/210177
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add a new loader method SymSortSub that sorts the sub-symbols
of a given outer symbol (designed to be compatible with the
existing sym.Symbol method).
Change-Id: Icd6627b2e6d04524d657e712cfd39fda0e0e080b
Reviewed-on: https://go-review.googlesource.com/c/go/+/211297
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The test for issue 8945 was marked to only run on gccgo, but there was
no reason for that. It broke for gccgo using GCC 10, because GCC 10
defaults to -fno-common. Make the test run on gc, and split it into
test.go and testx.go to make it work with GCC 10.
The test for issue 9026 used two identical structs which GCC 10 turns
into the same type. The point of the test is not that the structs are
identical, but that they are handled in a particular order. So make
them different.
Updates #8945
Updates #9026
Change-Id: I000fb02f88f346cfbbe5dbefedd944a2c64e8d8e
Reviewed-on: https://go-review.googlesource.com/c/go/+/211217
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
nanotime1 and walltime1 do not preserve BP on linux amd64. Previously, this
did not cause a problem, because nanotime/walltime do preserve the BP. But now
with mid-stack inlining, nanotime/walltime are usually inlined, so BP is not
preserved. So, the BP is now wrong in any function after a call to
nanotime()/walltime() on amd64. That means the frame pointer on the stack can
be wrong for any further function call made after the nanotime() call (notably
runtime.main and various GC functions). [386 doesn't use framepointer.]
Fix is to set a frame size of 8 for nanotime1 and walltime1, which means the
standard prolog/epilog that saves/restore BP in the stack frame is added.
I noticed this while investigating issue 16638 (use frame pointers for
runtime.Callers). This change would needed for progress on that issue (which
doesn't have a high priority). Verified that this fix works/is useful for issue
16638.
Change-Id: I19e19ef2c1a517d737a34928baae034f2eb0b2c2
Reviewed-on: https://go-review.googlesource.com/c/go/+/212079
Run-TryBot: Dan Scales <danscales@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The documentation for RecentTag indicates that it returns an actual
tag, not a canonicalized prefix+version blob equivalent to a tag,
so the canonicalization due to semver.Max seems like a bug here.
Fortunately, RecentTag is not currently ever actually used as a tag,
so the removal of metadata does not result in a user-facing bug.
Nonetheless, it may be a subtle source of confusion for maintainers
in the future.
Updates #32700
Change-Id: I525423c1c0c7ec7c36c09e53b180034474f74e5a
Reviewed-on: https://go-review.googlesource.com/c/go/+/212202
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
I noticed the missing diagnostic when writing a regression test for #33795.
Change-Id: Ic3249436a6109d71f9ff720b7096f9b872f6a94b
Reviewed-on: https://go-review.googlesource.com/c/go/+/212201
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
The 'go' command normally requires the 'go.mod' files for replacement
modules to have a major version compatible with the module they are
replacing.
However, prior to CL 206761, the 'go' command erroneously allowed
unversioned paths (which imply major version 0 or 1) to replace
'gopkg.in' paths with any major-version suffix.
An analysis of proxy.golang.org suggests that these replacements,
while uncommon, are not unheard-of. Rather than breaking the modules
that rely on them, we will continue to allow the erroneous replacement
paths for this particular pairing.
Updates #34254
Change-Id: Icb4e745981803edaa96060f17a8720a058219ab1
Reviewed-on: https://go-review.googlesource.com/c/go/+/212105
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
When the -modfile flag is in use (either explicitly or from GOFLAGS),
'go list -m' will now print the effective go.mod file for the main
module in the GoMod field in -f or -json output.
Fixes#36220
Updates #34506
Change-Id: I89c2ee40f20e07854bb37c6e4e13eeea0cce7b0d
Reviewed-on: https://go-review.googlesource.com/c/go/+/212100
Run-TryBot: Jay Conrod <jayconrod@google.com>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
The recently added slice function used indirectInterface, but then
forgot to actually call reflect.Value.Slice on its result. Calling the
Slice method on the original Value without indirectInterface would
result in a panic, if our slice was indeed behind an interface.
Fix that, and add test cases for all three built-in functions that work
with slices.
Fixes#36199.
Change-Id: I9a18f4f604a3b29967eefeb573f8960000936b88
Reviewed-on: https://go-review.googlesource.com/c/go/+/211877
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
We don't asynchronously preempt if we are in the runtime. We do
this by checking the function name. However, it failed to take
inlining into account. If a runtime function gets inlined into
a non-runtime function, it can be preempted, and bad things can
happen. One instance of this is dounlockOSThread inlined into
UnlockOSThread which is in turn inlined into a non-runtime
function.
Fix this by using the innermost frame's function name.
Change-Id: Ifa036ce1320700aaaefd829b4bee0d04d05c395d
Reviewed-on: https://go-review.googlesource.com/c/go/+/211978
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Add a loader mechanism for recording outer/sub relationships between
symbols without falling back on sym.Symbol. Also includes a new
"PrependSub" method that provides a way to chain a sub-symbol only the
list of an outer symbol (a common operation when manipulating
outer/sub relationships in the linker).
Change-Id: I70c72356945ceec2bacdcdc25bcc352bfb6765a1
Reviewed-on: https://go-review.googlesource.com/c/go/+/210777
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add loader methods SymValue() and SetSymValue() to get/set the
value of a symbol by global index.
Change-Id: Ifc71480fc34c719ad00506d0828edf36c1a57119
Reviewed-on: https://go-review.googlesource.com/c/go/+/211302
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Add in a collection of new loader interfaces for getting/setting
symbol attributes, e.g. properties that would normally be part of the
sym.Symbol "Attr" field. This change also moves references to the
loaders 'reachable' bitmap behind a pair of loader methods, so that we
a consistent way of accessing symbol attributes overall. It is worth
noting that not every symbol attribute is backed by a bitmap; for some
infrequently used attributes, a map[Sym]struct{} is used instead.
Change-Id: I0010c9cd928d41b4bb6cdf45db4581e11c3c5db3
Reviewed-on: https://go-review.googlesource.com/c/go/+/210778
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
Create loader infrastructure for constructing the payloads of external
symbols from scratch, as opposed to passing in a sym.Symbol object
containing the payload.
The general idea is that clients can use the loader to create new
external Sym's using loader.AddExtSym, and then can add
relocations/data to the new sym with symbol builder interfaces (to be
provided in an subsequent patch), as opposed to having to use
sym.Symbol.
This change preserves compatibility with the old way of doing things
(passing in sym.Symbol) via a new loader.InstallSym method. If a
client invokes this method for a specific Sym, then the loader keeps
track of this fact and uses the sym.Symbol as the backing store instead.
Also included is a small unit test for the new interfaces -- not clear
whether this really needs to be kept around long term... it was mainly
useful during initial bringup.
Change-Id: If8ab15df7b64636e56b317155dfe6d7cdfe23b71
Reviewed-on: https://go-review.googlesource.com/c/go/+/207606
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
This makes the check the same as the one in the tests vet check.
It's safer to check the number of arguments rather than for a nil
slice.
Change-Id: I8e04e9c612573f334770c1c4245238649656c6e2
Reviewed-on: https://go-review.googlesource.com/c/go/+/211598
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>
The comment "If the name is the name of this template, overwrite this template."
is incorrect and should be "is not" instead. This comment is no longer
required once the docs are updated to mention this behaviour instead.
Fixes#34695
Change-Id: I773495b2194d7bb7619b13c1a28cbc76e8f69aac
Reviewed-on: https://go-review.googlesource.com/c/go/+/199139
Reviewed-by: Rob Pike <r@golang.org>
Cherry Zhang
Rhys Hiltner
Dmitri Shuralyov
Tobias Klauser
Josh Bleecher Snyder
Than McIntosh
Michael Anthony Knyszek
Ian Lance Taylor
Ariel Mashraki
Isfan Azhabil
Joel Sing
Alberto Donizetti
Austin Clements
Dan Scales
Bryan C. Mills
Jay Conrod
Daniel Martí
Gert Cuykens
Michael Matloob
Oliver Powell