The first word of an interface is a pointer, but for the purposes
of GC we don't need to treat it as such.
1. If it is a non-empty interface, the pointer points to an itab
which is always in persistentalloc space.
2. If it is an empty interface, the pointer points to a _type.
a. If it is a compile-time-allocated type, it points into
the read-only data section.
b. If it is a reflect-allocated type, it points into the Go heap.
Reflect is responsible for keeping a reference to
the underlying type so it won't be GCd.
If we ever have a moving GC, we need to change this for 2b (as
well as scan itabs to update their itab._type fields).
Write barriers on the first word of interfaces have already been removed.
Change-Id: I643e91d7ac4de980ac2717436eff94097c65d959
Reviewed-on: https://go-review.googlesource.com/97518
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Make the hasSideEffects func use type information to see if a CallExpr
is a type conversion or not. In case it is, there cannot be any side
effects.
Now that vet always has type information, we can afford to use it here.
Update the tests and remove the TODO there too.
Change-Id: I74fdacf830aedf2371e67ba833802c414178caf1
Reviewed-on: https://go-review.googlesource.com/79536
Reviewed-by: Robert Griesemer <gri@golang.org>
Explicitly whitelist args of OpSelect{1|2} that zero upper 32 bits.
Use better values in corresponding test.
This should have been a part of CL 96815, but it was submitted, before
relevant comments.
Change-Id: Ic85d90a4471a17f6d64f8f5c405f21378bf3a30d
Reviewed-on: https://go-review.googlesource.com/97295
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
On amd64 we optimize encoding/binary.BigEndian.PutUint{16,32,64}
into bswap + single store, but strangely enough not LittleEndian.PutUint{16,32}.
We have similar rules, but they use 64-bit shifts everywhere,
and fail for 16/32-bit case. Add rules that matchLittleEndian.PutUint,
and relevant tests. Performance results:
LittleEndianPutUint16-6 1.43ns ± 0% 1.07ns ± 0% -25.17% (p=0.000 n=9+9)
LittleEndianPutUint32-6 2.14ns ± 0% 0.94ns ± 0% -56.07% (p=0.019 n=6+8)
LittleEndianPutUint16-6 1.40GB/s ± 0% 1.87GB/s ± 0% +33.24% (p=0.000 n=9+9)
LittleEndianPutUint32-6 1.87GB/s ± 0% 4.26GB/s ± 0% +128.54% (p=0.000 n=8+8)
Discovered, while looking at ethereum_ethash from community benchmarks
Change-Id: Id86d5443687ecddd2803edf3203dbdd1246f61fe
Reviewed-on: https://go-review.googlesource.com/95475
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
We accidentally overlooked needing to still visit Ninit for OIF
statements with constant conditions in golang.org/cl/96778.
Fixes#24120.
Change-Id: I5b341913065ff90e1163fb872b9e8d47e2a789d2
Reviewed-on: https://go-review.googlesource.com/97475
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
LLVM tools, particularly lldb and dsymutil, don't support base address
selection entries in location lists. When targeting GOOS=darwin,
mode, have the linker translate location lists to CU-relative form
instead.
Technically, this isn't necessary when linking internally, as long as
nobody plans to use anything other than Delve to look at the DWARF. But
someone might want to use lldb, and it's really confusing when dwarfdump
shows gibberish for the location entries. The performance cost isn't
noticeable, so enable it even for internal linking.
Doing this in the linker is a little weird, but it was more expensive in
the compiler, probably because the compiler is much more stressful to
the GC. Also, if we decide to only do it for external linking, the
compiler can't see the link mode.
Benchmark before and after this commit on Mac with -dwarflocationlists=1:
name old time/op new time/op delta
StdCmd 21.3s ± 1% 21.3s ± 1% ~ (p=0.310 n=27+27)
Only StdCmd is relevant, because only StdCmd runs the linker. Whatever
the cost is here, it's not very large.
Change-Id: I200246dedaee4f824966f7551ac95f8d7123d3b1
Reviewed-on: https://go-review.googlesource.com/89535
Reviewed-by: David Chase <drchase@google.com>
The pipe2 syscall is part of OpenBSD since version 5.7 and thus exists in
all officially supported versions.
Follows CL 38426 and CL 94035
Change-Id: I8f93ecbc89664241f1b6b0d069e948776941b1d0
Reviewed-on: https://go-review.googlesource.com/97356
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The branchelim pass makes some blocks unreachable, but does not
remove them from Func.Values. Consequently, ssacheck complains
when it finds a block with a non-zero likeliness value but no
successors.
Fixes#24014
Change-Id: I2dcf1d8f4e769a2f363508dab3b11198ead336b6
Reviewed-on: https://go-review.googlesource.com/96075
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Philip Hofer <phofer@umich.edu>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Minor improvements, noticed while investigating other things.
Shorten the prologue.
Make branch direction better for static branch prediction;
the most common case by far is switching stacks (g==curg).
Change-Id: Ib2211d3efecb60446355cda56194221ccb78057d
Reviewed-on: https://go-review.googlesource.com/97377
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When a var or const declaration contains a mixture of exported and unexported
identifiers, replace the unexported identifiers with underscore.
Otherwise, the LHS and the RHS may mismatch or the declaration may mismatch
with an iota from above.
Fixes#22426
Change-Id: Icd5fb81b4ece647232a9f7d05cb140227091e9cb
Reviewed-on: https://go-review.googlesource.com/94877
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Bit-test rules failed to match when matching the highest bit
of a word because operands in SSA are signed int64. Fix
them by treating them as unsigned (and correctly handling
32-bit operands as well).
Tests will be added in next CL.
Change-Id: I491c4e88e7e2f87e9bb72bd0d9fa5d4025b90736
Reviewed-on: https://go-review.googlesource.com/94765
Reviewed-by: Keith Randall <khr@golang.org>
Spotted while working on #18943, it triggers once during bootstrap.
Change-Id: Ia4330ccc6395627c233a8eb4dcc0e3e2a770bea7
Reviewed-on: https://go-review.googlesource.com/94764
Reviewed-by: Keith Randall <khr@golang.org>
Allow the compiler to generate code like CMPQ 16(AX), $7
It's tricky because it's difficult to spill such a comparison during
flagalloc, because the same memory state might not be available at
the restore locations.
Solve this problem by decomposing the compare+load back into its parts
if it needs to be spilled.
The big win is that the write barrier test goes from:
MOVL runtime.writeBarrier(SB), CX
TESTL CX, CX
JNE 60
to
CMPL runtime.writeBarrier(SB), $0
JNE 59
It's one instruction and one byte smaller.
Fixes#19485Fixes#15245
Update #22460
Binaries are about 0.15% smaller.
Change-Id: I4fd8d1111b6b9924d52f9a0901ca1b2e5cce0836
Reviewed-on: https://go-review.googlesource.com/86035
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ilya Tocar <ilya.tocar@intel.com>
Previously, finishcompare just used SetTypecheck, but this didn't
recursively update any untyped bool typed subexpressions. This CL
changes it to call typecheck, which correctly handles this.
Also cleaned up outdated code for simplifying logic.
Updates #23834
Change-Id: Ic7f92d2a77c2eb74024ee97815205371761c1c90
Reviewed-on: https://go-review.googlesource.com/97035
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Currently we generate NEGQ for DIV{Q,L,W}. By generating NEGL and NEGW,
we will reduce code size, because NEGL doesn't require rex prefix.
This also guarantees that upper 32 bits are zeroed, so we can revert CL 85736,
and remove zero-extensions of DIVL results.
Also adds test for redundant zero extend elimination.
Fixes#23310
Change-Id: Ic58c3104c255a71371a06e09d10a975bbe5df587
Reviewed-on: https://go-review.googlesource.com/96815
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
FileHeader.Name also reflects this fact.
Fixes#24018
Change-Id: Id0860a9b23c264ac4c6ddd65ba20e0f1f36e4865
Reviewed-on: https://go-review.googlesource.com/97057
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
The output of go with -x flag is formatted in a manner that file paths
under current directory are modified to start with a dot (.), but when
the directory path ends with a slash (/), the formatting goes wrong.
Fixes#23982
Change-Id: I8f8d15dd52bee882a9c6357eb9eabdc3eaa887c3
GitHub-Last-Rev: 1493f38baf
GitHub-Pull-Request: golang/go#23985
Reviewed-on: https://go-review.googlesource.com/95755
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This is for debugging the reported flaky tests.
Update #24081
Change-Id: Ica046928f675d69e38251a47a6f225efedce920c
Reviewed-on: https://go-review.googlesource.com/96855
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Change https://go-review.googlesource.com/79575 fixed the computation
of recursive method sets by separating the method set computation from
type computation. However, it didn't track an embedded method's scope
and as a result, some methods' signatures were typed in the wrong
context.
This change tracks embedded methods together with their scope and
uses that scope for the correct context setup when typing those
method signatures.
Fixes#23914.
Change-Id: If3677dceddb43e9db2f9fb3c7a4a87d2531fbc2a
Reviewed-on: https://go-review.googlesource.com/96376
Reviewed-by: Alan Donovan <adonovan@google.com>
When using the special import "C", the "cgo" build constraint is implied for the go file,
potentially triggering unclear "undefined" error messages.
Explicitly explain this in the documentation.
Updates #24068
Change-Id: Ib656ceccd52c749ffe7fb2d3db9ac144f17abb32
GitHub-Last-Rev: 5a13f00a9b
GitHub-Pull-Request: golang/go#24072
Reviewed-on: https://go-review.googlesource.com/96655
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Extend cmd/internal/src.PosBase to track column information,
and adjust the meaning of the PosBase position to mean the
position at which the PosBase's relative (line, col) position
starts (rather than indicating the position of the //line
directive). Because this semantic change is made in the
compiler's noder, it doesn't affect the logic of src.PosBase,
only its test setup (where PosBases are constructed with
corrected incomming positions). In short, src.PosBase now
matches syntax.PosBase with respect to the semantics of
src.PosBase.pos.
For #22662.
Change-Id: I5b1451cb88fff3f149920c2eec08b6167955ce27
Reviewed-on: https://go-review.googlesource.com/96535
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
For line directives which have a line and a column number,
an omitted filename means that the filename has not changed
(per the issue below).
For line directives w/o a column number, an omitted filename
means the empty filename (to preserve the existing behavior).
For #22662.
Change-Id: I32cd9037550485da5445a34bb104706eccce1df1
Reviewed-on: https://go-review.googlesource.com/96476
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Despite the existing test that locks in the allocation behavior, people
really want a benchmark. So:
BenchmarkBuildString_Builder/1Write_NoGrow-4 20000000 60.4 ns/op 48 B/op 1 allocs/op
BenchmarkBuildString_Builder/3Write_NoGrow-4 10000000 230 ns/op 336 B/op 3 allocs/op
BenchmarkBuildString_Builder/3Write_Grow-4 20000000 102 ns/op 112 B/op 1 allocs/op
BenchmarkBuildString_ByteBuffer/1Write_NoGrow-4 10000000 125 ns/op 160 B/op 2 allocs/op
BenchmarkBuildString_ByteBuffer/3Write_NoGrow-4 5000000 339 ns/op 400 B/op 3 allocs/op
BenchmarkBuildString_ByteBuffer/3Write_Grow-4 5000000 316 ns/op 336 B/op 3 allocs/op
I don't think these allocate-as-fast-as-you-can benchmarks are very
interesting because they're effectively just GC benchmarks, but sure.
If one wants to see that there's 1 fewer allocation, there it is. The
ns/op and B/op numbers will change as the built string size changes.
Updates #18990
Change-Id: Ifccf535bd396217434a0e6989e195105f90132ae
Reviewed-on: https://go-review.googlesource.com/96980
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>
Error returns for linux/arm syscalls are handled since a long time.
Remove another list of unimplemented syscalls, following CL 96315.
The root-only check in TestSyscallNoError was shown to be sufficient as
part of CL 84485 already.
NetBSD and OpenBSD do not implement the sendfile syscall (yet), so add a
link to golang.org/issue/5847
Change-Id: I07efc3c3203537a4142707385f31b59dc0ecca42
Reviewed-on: https://go-review.googlesource.com/97115
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
On Darwin and FreeBSD, supportsCloseOnExec is defined in its own file,
even though it is set to true as on other Unices. Drop the separate
definitions but keep the accompanying comments.
Change-Id: Iab1d20e1b2590800f141d54b55a099c9cd7ae57e
Reviewed-on: https://go-review.googlesource.com/97155
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Fixes#23123
Change-Id: Ia4ac947cc49ef3d150ef60a095b86552dcef397d
Reviewed-on: https://go-review.googlesource.com/84435
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Giovanni Bajo <rasky@develer.com>
The SOCK_CLOEXEC and SOCK_NONBLOCK flags to the socket syscall and the
accept4 syscall are supported since OpenBSD 5.7.
Follows CL 40895 and CL 94295
Change-Id: Icaf35ace2ef5e73279a70d4f1a9fbf3be9371e6c
Reviewed-on: https://go-review.googlesource.com/97196
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Contrary to bash, double quotes cannot be used to group
arguments in Windows shell, so they were being printed as
literals by the echo command.
Since a literal '>' is present in the string, it is sufficient
to escape it correctly through '^'.
Change-Id: Icc8c92b3dc8d813825adadbe3d921a38d44a1a94
Reviewed-on: https://go-review.googlesource.com/97056
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
There are a few places where the integer value is used.
Use the equivalent constants to aid with readability.
Change-Id: I023b1dbe605340544c056d0e0d9d6d5a7d7d0edc
GitHub-Last-Rev: c1c90bcd25
GitHub-Pull-Request: golang/go#24123
Reviewed-on: https://go-review.googlesource.com/96984
Reviewed-by: Andrew Bonventre <andybons@golang.org>
CL 14624 introduced this label. At that time,
the switch-case had a break to label statement which made this necessary.
But now, the code no longer has a break statement and it directly returns.
Hence, it is no longer necessary to have a label.
Change-Id: Idde0fcc4d2db2d76424679f5acfe33ab8573bce4
Reviewed-on: https://go-review.googlesource.com/96935
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
newUserFromSid() is extended so that the retriaval of the user home
path based on a user SID becomes possible.
(1) The primary method it uses is to lookup the Windows registry for
the following key:
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList\[SID]
If the key does not exist the user might not have logged in yet.
If (1) fails it falls back to (2)
(2) The second method the function uses is to look at the default home
path for users (e.g. WINAPI's GetProfilesDirectory()) and append
the username to that. The procedure is in the lines of:
c:\Users + \ + <username>
The function newUser() now requires the following arguments:
uid, gid, dir, username, domain
This is done to avoid multiple calls to usid.String() and
usid.LookupAccount("") in the case of a newUserFromSid()
call stack.
The functions current() and newUserFromSid() both call newUser()
supplying the arguments in question. The helpers
lookupUsernameAndDomain() and findHomeDirInRegistry() are
added.
This commit also updates:
- go/build/deps_test.go, so that the test now includes the
"internal/syscall/windows/registry" import.
- os/user/user_test.go, so that User.HomeDir is tested on Windows.
GitHub-Last-Rev: 25423e2a38
GitHub-Pull-Request: golang/go#23822
Change-Id: I6c3ad1c4ce3e7bc0d1add024951711f615b84ee5
Reviewed-on: https://go-review.googlesource.com/93935
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
With its new -linecomment flag, it is now possible to use stringer on
values whose strings aren't valid identifiers. This is the case with
tokens and operators in Go.
Operator alredy had inline comments with each operator's string
representation; only minor modifications were needed. The inline
comments were added to each of the token names, using the same strategy.
Comments that were previously inline or part of the string arrays were
moved to the line immediately before the name they correspond to.
Finally, declare tokStrFast as a function that uses the generated arrays
directly. Avoiding the branch and strconv call means that we avoid a
performance regression in the scanner, perhaps due to the lack of
mid-stack inlining.
Performance is not affected. Measured with 'go test -run StdLib -fast'
on an X1 Carbon Gen2 (i5-4300U @ 1.90GHz, 8GB RAM, SSD), the best of 5
runs before and after the changes are:
parsed 1709399 lines (3763 files) in 1.707402159s (1001169 lines/s)
allocated 449.282Mb (263.137Mb/s)
parsed 1709329 lines (3765 files) in 1.706663154s (1001562 lines/s)
allocated 449.290Mb (263.256Mb/s)
Change-Id: Idcc4f83393fcadd6579700e3602c09496ea2625b
Reviewed-on: https://go-review.googlesource.com/95357
Reviewed-by: Robert Griesemer <gri@golang.org>
