[dev.link] cmd/link: accept more types in Xcoffadddynrel
In dodata we overwrite symbol types to SDATA. Now we'll stop
doing that, so accept more symbol types here. This is basically
a list of all writeable types handled in dodata that could appear
in XCOFF.
Than McIntosh [Fri, 24 Apr 2020 19:32:46 +0000 (15:32 -0400)]
[dev.link] cmd/link: support new dodata for PPC64
Add linux/{ppc64,ppc64le} and aix/ppc64 arch support for the new
dodata() phase.
This completes the picture in terms of architecture support for the
new dodata(), but to be safe this patch leaves the command line flag
in place there are problems on the builders (especially given that we
have a dead aix-ppc64 builder).
[dev.link] cmd/link: stop setting ReadOnly attribute in late stage
The ReadOnly attribute was used to do copy on write when applying
relocations to symbols with read-only backing stores. Now that we
always apply relocations in the output buffer (mmap or heap), it
is always writeable. No need to tamper with the ReadOnly
attribute anymore.
Wasm is an exception, where we don't copy symbol contents to the
output buffer first. Do copy-on-write there.
This is in preparation of converting reloc to using the loader.
Than McIntosh [Fri, 24 Apr 2020 15:07:17 +0000 (11:07 -0400)]
[dev.link] cmd/link: create symbol updated lazily in amd64 adddynrel
Tweak the code in the amd64 version of adddynrel to avoid creating a
symbol updated for the symbol being processed until it's clear we need
to alter its relocations. This should help performance for the
PIE+internal linking scenario.
[dev.link] cmd/link: check fingerprint for index consistency
Previous CL introduced index fingerprint in the object files.
This CL implements the second part: checking fingerprint
consistency in the linker when packages are loaded.
Change-Id: I05dd4c4045a65adfd95e77b625d6c75a7a70e4f1
Reviewed-on: https://go-review.googlesource.com/c/go/+/229618
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org>
[dev.link] cmd/internal/goobj2: add index fingerprint to object file
The new object files use indices for symbol references, instead
of names. Fundamental to the design, it requires that the
importing and imported packages have consistent view of symbol
indices. The Go command should already ensure this, when using
"go build". But in case it goes wrong, it could lead to obscure
errors like run-time crashes. It would be better to check the
index consistency at build time.
To do that, we add a fingerprint to each object file, which is
a hash of symbol indices. In the object file it records the
fingerprints of all imported packages, as well as its own
fingerprint. At link time, the linker checks that a package's
fingerprint matches the fingerprint recorded in the importing
packages, and issue an error if they don't match.
This CL does the first part: introducing the fingerprint in the
object file, and propagating fingerprints through
importing/exporting by the compiler. It is not yet used by the
linker. Next CL will do.
Change-Id: I0aa372da652e4afb11f2867cb71689a3e3f9966e
Reviewed-on: https://go-review.googlesource.com/c/go/+/229617 Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org>
In the code there are conditions like !ctxt.IsDarwin(). This will
accidentally be true if HeadType is not yet set. Panic when
HeadType is not set, to catch errors.
Than McIntosh [Tue, 21 Apr 2020 22:37:43 +0000 (18:37 -0400)]
[dev.link] cmd/link: begin converting dodata() to loader APIs
This patch begins the work of converting the linker's dodata phase to
work with loader APIs. Passes all.bash on linux/amd64, but hasn't been
tested on anything else (more arch-specific code needs to be written).
Use of the new dodata() phase is currently gated by a temporary
command line flag ("-newdodata"), and there is code in the linker's
main routine to insure that we only use the new version for the right
GOOS/GOARCH (currently restricted to ELF + AMD64).
Than McIntosh [Wed, 22 Apr 2020 19:16:06 +0000 (15:16 -0400)]
[dev.link] cmd/link: move more error handling into loader
Move the guts of ctxt.Errorf into loader.Loader, so that we can make
calls to it from functions that have a "*loader.Loader" available but
not a "ctxt *Link". This is needed to start converting hooks like
"adddynrel" in the arch-specific portions of the linker to use loader
APIs.
Change-Id: Ieedd4583b66504be0e77d7f3fbadafe0d2307a69
Reviewed-on: https://go-review.googlesource.com/c/go/+/229497
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>
Clients may need to invoke the loader.Reloc2.SetType method to reset
the type of a relocation from external flavor to internal flavor,
meaning that the external type add-in needs to be zeroed (this is
needed when adding dynsym entries).
Add a new SymbolBuider method to support mutating the type of a reloc
for an external symbol, so that the external type can be changed as
well (Reloc2 doesn't have access to that). Also add similar methods
for updating target symbol and addend, so as to have a consistent
interface for ext reloc mutation.
Than McIntosh [Thu, 23 Apr 2020 12:43:29 +0000 (08:43 -0400)]
[dev.link] cmd/link/internal/loader: fix buglet in section handling
Allow for the possibility that a client could call newExtSym(), then
ask for the section of the new sym before SetSectSym is called on it
(check in SymSect for this case).
Change-Id: I7bd78e7b3b7618943705b616f62ea78c4a1b68d0
Reviewed-on: https://go-review.googlesource.com/c/go/+/229603 Reviewed-by: Jeremy Faller <jeremy@golang.org>
Johan Jansson [Mon, 20 Apr 2020 18:35:57 +0000 (21:35 +0300)]
cmd/go: allow generate to process invalid packages
Allow go generate to process packages that contain invalid code. Ignore
errors when loading the package, but process only files which have a
valid package clause. Set $GOPACKAGE individually for each file, based
on the package clause.
Add test script for go generate and invalid packages.
Fixes #36422
Change-Id: I91ea088346a1548ccd6678b4595a527b948331ff
Reviewed-on: https://go-review.googlesource.com/c/go/+/229097 Reviewed-by: Rob Pike <r@golang.org> Reviewed-by: Jay Conrod <jayconrod@google.com>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Matthew Dempsky [Tue, 21 Apr 2020 22:37:29 +0000 (15:37 -0700)]
cmd/compile: refactor variadac call desugaring
In mid-Walk, we rewrite calls to variadic functions to use explicit
slice literals; e.g., rewriting f(a,b,c) into f([]T{a,b,c}...).
However, it would be useful to do that rewrite much earlier in the
compiler, so that other compiler passes can be simplified.
This CL refactors the rewrite logic into a new fixVariadicCall
function, which subsequent CLs can more easily move into earlier
compiler passes.
Passes toolstash-check -race.
Change-Id: I408e655f2d3aa00446a2e6accf8765abc3b16a8a
Reviewed-on: https://go-review.googlesource.com/c/go/+/229486
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
ioutil.TempDir doesn't like path separators in its pattern. Modify
(*common).TempDir to replace path separators with underscores before
using the test name as a pattern for ioutil.TempDir.
Matthew Dempsky [Wed, 22 Apr 2020 21:37:02 +0000 (14:37 -0700)]
cmd/compile: be stricter about recognizing safety rule #4
unsafe.Pointer safety rule #4 says "The compiler handles a Pointer
converted to a uintptr in the argument list of a call". Within escape
analysis, we've always required this be a single conversion
unsafe.Pointer->uintptr conversion, but the corresponding logic in
order is somewhat laxer, allowing arbitrary chains of OCONVNOPs from
unsafe.Pointer to uintptr.
This CL changes order to be stricter to match escape analysis.
Passes toolstash-check.
Change-Id: Iadd210d2123accb2020f5728ea2a47814f703352
Reviewed-on: https://go-review.googlesource.com/c/go/+/229578 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Jeremy Faller [Wed, 22 Apr 2020 16:13:33 +0000 (12:13 -0400)]
[dev.link] cmd/link: only allow heap area to grow to 10MB
With CL 228782, we've removed file I/O, but we're growing the memory too
much. This change will periodically flush the heap area to the mmapped
area (if possible).
Change-Id: I1622c738ee5a1a6d02bff5abb0a5751caf8095c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/229439
Run-TryBot: Jeremy Faller <jeremy@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Cherry Zhang <cherryyz@google.com> Reviewed-by: Than McIntosh <thanm@google.com>
Hana (Hyang-Ah) Kim [Wed, 22 Apr 2020 20:24:30 +0000 (16:24 -0400)]
net/http/pprof: allow "seconds" parameters to most profiles
golang.org/cl/147598 added the support for delta computation for mutex
and block profiles. In fact, this delta computation makes sense for
other types of profiles.
For example, /debug/pprof/allocs?seconds=x will provide how much allocation
was made during the specified period. /debug/pprof/goroutine?seconds=x will
provide the changes in the list of goroutines. This also makes sense for
custom profiles.
Update #23401
Update google/pprof#526
Change-Id: I45e9073eb001ea5b3f3d16e5a57f635193610656
Reviewed-on: https://go-review.googlesource.com/c/go/+/229537
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Hana (Hyang-Ah) Kim [Wed, 22 Apr 2020 19:35:45 +0000 (15:35 -0400)]
net/http/pprof: make TestDeltaProfile less flaky by retrying
In some slow environment, the goroutine for mutexHog2 may not run
within 1secs. So, try with increasing seconds parameters,
and declare failure if it still fails with the longest duration
parameter (32sec).
Also, relax the test condition - previously we expected the
profile's duration is within 0.5~2sec. But obviously, in some
slow environment, that's not even guaranteed. Just check we get
non-zero duration in the result.
Update #38544
Change-Id: Ia9b0d51429a2093e6c9eb92cf463ff6952ef3e10
Reviewed-on: https://go-review.googlesource.com/c/go/+/229498
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com> Reviewed-by: Ian Lance Taylor <iant@golang.org>
Michael Munday [Mon, 17 Feb 2020 11:43:33 +0000 (03:43 -0800)]
cmd/compile: clean up codegen for branch-on-carry on s390x
This CL optimizes code that uses a carry from a function such as
bits.Add64 as the condition in an if statement. For example:
x, c := bits.Add64(a, b, 0)
if c != 0 {
panic("overflow")
}
Rather than converting the carry into a 0 or a 1 value and using
that as an input to a comparison instruction the carry flag is now
used as the input to a conditional branch directly. This typically
removes an ADD LOGICAL WITH CARRY instruction when user code is
doing overflow detection and is closer to the code that a user
would expect to generate.
Change-Id: I950431270955ab72f1b5c6db873b6abe769be0da
Reviewed-on: https://go-review.googlesource.com/c/go/+/219757
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
The code that runs as a part of loadlibfull converts the linker's
outer/sub state and sets the sym.Symbol AttrSubSymbol if a symbol has
both A) an outer sym, and B) is listed as a sub-symbol by some other
symbol.
Make sure that we have the same logic in the original loader method,
since we need to use it as part of dodata() prior to loadlibfull.
Change the timing for preprocessing of integer/floating point constant
symbols so that we populate them with content at an earlier stage.
This is needed to allow them can be picked up by the loader-API
version of dodata().
Change-Id: Icf09f4f4b318b4f77e11d4a0f0a9cbecd76a1d6b
Reviewed-on: https://go-review.googlesource.com/c/go/+/229438
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>
David Finkel [Sun, 4 Aug 2019 19:14:48 +0000 (15:14 -0400)]
runtime/pprof: plumb labels for goroutine profiles
Goroutines are directly associated with labels. It's relatively easy to
plumb those through without creating goroutine-locals in the wild.
This is accomplished by splitting out most of the code from the public
`runtime.GoroutineProfile` into a new unexported
`runtime.goroutineProfileWithLabels`, which then has a thin wrapper
linked into the `runtime/pprof` package as
`runtime_goroutineProfileWithLabels`. (mirroring the way labels get
associated with the `g` for a goroutine in the first place)
Per-#6104, OS-thread creation profiles are a bit useless, as `M`s tend
to be created be created by a background goroutine. As such, I decided
not to add support for capturing the labels at `M`-creation-time, since
the stack-traces seem to always come out `nil` for my simple test
binaries.
This change currently provides labels for debug=0 and debug=1, as
debug=2 is currently entirely generated by the runtime package and I
don't see a clean way of getting the `labelMap` type handled properly
within the `runtime` package.
Update the comment added in cl/131275 to mention goroutine support for
labels.
Updates #23458
Change-Id: Ia4b558893d7d10156b77121cd9b70c4ccd9e1889
Reviewed-on: https://go-review.googlesource.com/c/go/+/189318 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Ruixin(Peter) Bao [Tue, 21 Apr 2020 19:14:11 +0000 (15:14 -0400)]
math/big: clean up whitespace in arith_s390x.s file
This CL looks big but it only does formatting changes to arith_s390x.s.
The file was formatted using asmfmt(https://github.com/klauspost/asmfmt)
, so there should not be any functional impact. I verified that the
generated assembly of big.test file is identical.
Change-Id: I8b4035ef082a4d0357881869327e25253f2d8be1
Reviewed-on: https://go-review.googlesource.com/c/go/+/229302 Reviewed-by: Michael Munday <mike.munday@ibm.com>
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
[dev.link] cmd/internal/goobj: add index to symbol name for indexed symbols
With old object files, when objdump an object file which, for
example, contains a call of fmt.Fprintf, it shows a symbol
reference like
R_CALL:fmt.Fprintf
With new object files, as the symbol reference is indexed, the
reference becomes
R_CALL:fmt.#33
The object file does not contain information of what symbol #33
in the fmt package is.
To make this more useful, print the index when dumping the symbol
definitions. This way, when dumping the fmt package, e.g.
"go tool nm fmt.a", it will print
6c705 T fmt.Fprintf#33
So we can find out what symbol #33 actually is.
Change-Id: I320776597d28615ce18dd0617c352d2b8180db49
Reviewed-on: https://go-review.googlesource.com/c/go/+/229246 Reviewed-by: Austin Clements <austin@google.com> Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org>
[dev.link] cmd/link: reduce memory usage for storing symbol section information
Currently, we use a dense array to store symbol's sections. The
array element is a *sym.Section, which takes 8 bytes per symbol
on a 64-bit machine. And the array is created upfront.
To reduce memory usage, use a 16-bit index for sections, so we
store 2 bytes per symbol. The array is pointerless, reducing GC
work. Also create the array lazily.
This reduces some memory usage: linking cmd/compile,
name old alloc/op new alloc/op delta
Loadlib_GC 42.1MB ± 0% 36.2MB ± 0% -14.01% (p=0.008 n=5+5)
name old live-B new live-B delta
Loadlib_GC 16.8M ± 0% 15.4M ± 0% -8.36% (p=0.008 n=5+5)
Archive_GC 98.2M ± 0% 97.2M ± 0% -1.02% (p=0.008 n=5+5) # at the end
Change-Id: If8c41eded8859660bca648c5e6fdf5830810fbf6
Reviewed-on: https://go-review.googlesource.com/c/go/+/229306 Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org>
Currently markrootSpans, the scanning routine which scans span specials
(particularly finalizers) as roots, uses sweepSpans to shard work and
find spans to mark.
However, as part of a future CL to change span ownership and how
mcentral works, we want to avoid having markrootSpans use the sweep bufs
to find specials, so in this change we introduce a new mechanism.
Much like for the page reclaimer, we set up a per-page bitmap where the
first page for a span is marked if the span contains any specials, and
unmarked if it has no specials. This bitmap is updated by addspecial,
removespecial, and during sweeping.
markrootSpans then shards this bitmap into mark work and markers iterate
over the bitmap looking for spans with specials to mark. Unlike the page
reclaimer, we don't need to use the pageInUse bits because having a
special implies that a span is in-use.
While in terms of computational complexity this design is technically
worse, because it needs to iterate over the mapped heap, in practice
this iteration is very fast (we can skip over large swathes of the heap
very quickly) and we only look at spans that have any specials at all,
rather than having to touch each span.
This new implementation of markrootSpans is behind a feature flag called
go115NewMarkrootSpans.
Matthew Dempsky [Mon, 20 Apr 2020 18:14:36 +0000 (11:14 -0700)]
cmd/compile: more precise analysis of method values
Previously for a method value "x.M", we always flowed x directly to
the heap, which led to the receiver argument generally needing to be
heap allocated.
This CL changes it to flow x to the closure and M's receiver
parameter. This allows receiver arguments to be stack allocated as
long as (1) the closure never escapes, *and* (2) method doesn't leak
its receiver parameter.
Within the standard library, this allows a handful of objects to be
stack allocated instead. Listed here are diagnostics that were
previously emitted by "go build -gcflags=-m std cmd" that are no
longer emitted:
archive/tar/writer.go:118:6: moved to heap: f
archive/tar/writer.go:208:6: moved to heap: f
archive/tar/writer.go:248:6: moved to heap: f
cmd/compile/internal/gc/initorder.go:252:2: moved to heap: d
cmd/compile/internal/gc/initorder.go:75:2: moved to heap: s
cmd/go/internal/generate/generate.go:206:7: &Generator literal escapes to heap
cmd/internal/obj/arm64/asm7.go:910:2: moved to heap: c
cmd/internal/obj/mips/asm0.go:415:2: moved to heap: c
cmd/internal/obj/pcln.go:294:22: new(pcinlineState) escapes to heap
cmd/internal/obj/s390x/asmz.go:459:2: moved to heap: c
crypto/tls/handshake_server.go:56:2: moved to heap: hs
Thanks to Cuong Manh Le for help coming up with this solution.
Matthew Dempsky [Mon, 20 Apr 2020 18:14:15 +0000 (11:14 -0700)]
cmd/compile: refactor Escape.tagHole
This CL refactors tagHole to handle all three call situations (unknown
function; known function in same analysis batch; known function in
previous analysis batch). This will make it somewhat easier to reuse
in a followup CL.
Michael Munday [Fri, 17 Apr 2020 12:05:07 +0000 (05:05 -0700)]
cmd/compile: optimize comparisons with immediates on s390x
When generating code for unsigned equals (==) and not equals (!=)
comparisons we currently, on s390x, always use signed comparisons.
This mostly works well, however signed comparisons on s390x sign
extend their immediates and unsigned comparisons zero extend them.
For compare-and-branch instructions which can only have 8-bit
immediates this significantly changes the range of immediate values
we can represent: [-128, 127] for signed comparisons and [0, 255]
for unsigned comparisons.
When generating equals and not equals checks we don't neet to worry
about whether the comparison is signed or unsigned. This CL
therefore adds rules to allow us to switch signedness for such
comparisons if it means that it brings a constant into range for an
8-bit immediate.
For example, a signed equals with an integer in the range [128, 255]
will now be implemented using an unsigned compare-and-branch
instruction rather than separate compare and branch instructions.
As part of this change I've also added support for adding a name
to block control values using the same `x:(...)` syntax we use for
value rules.
Triggers 792 times when compiling cmd and std.
Change-Id: I77fa80a128f0a8ce51a2888d1e384bd5e9b61a77
Reviewed-on: https://go-review.googlesource.com/c/go/+/228642
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
Reason for revert: This May have caused issue 38567.
Change-Id: I2afa6a9d42cb29cfad09e706fb465c57e3774abd
Reviewed-on: https://go-review.googlesource.com/c/go/+/229301 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Jay Conrod [Tue, 21 Apr 2020 15:29:51 +0000 (11:29 -0400)]
cmd/go/internal/load: load imports for all package data errors
go/build.Import can return errors for many different reasons like
inconsistent package clauses or errors parsing build constraints.
It will still return a *build.Package with imports from files it was
able to process. Package.load should load these imports, even after an
unknown error.
There is already a special case for scanner.ErrorList (parse
error). This CL expands that behavior for all errors.
Fixes #38568
Change-Id: I871827299c556f1a9a5b12e7755b221e9d8c6e0e
Reviewed-on: https://go-review.googlesource.com/c/go/+/229243 Reviewed-by: Bryan C. Mills <bcmills@google.com>
cmd/compile: detect and diagnose invalid //go: directive placement
Thie CL changes cmd/compile/internal/syntax to give the gc half of
the compiler more control over pragma handling, so that it can prepare
better errors, diagnose misuse, and so on. Before, the API between
the two was hard-coded as a uint16. Now it is an interface{}.
This should set us up better for future directives.
In addition to the split, this CL emits a "misplaced compiler directive"
error for any directive that is in a place where it has no effect.
I've certainly been confused in the past by adding comments
that were doing nothing and not realizing it. This should help
avoid that kind of confusion.
The rule, now applied consistently, is that a //go: directive
must appear on a line by itself immediately before the declaration
specifier it means to apply to. See cmd/compile/doc.go for
precise text and test/directive.go for examples.
This may cause some code to stop compiling, but that code
was broken. For example, this code formerly applied the
//go:noinline to f (not c) but now will fail to compile:
Than McIntosh [Fri, 17 Apr 2020 21:23:02 +0000 (17:23 -0400)]
[dev.link] cmd/link: refactor section creation in dodata
Additional cleanups and refactorings in the allocateSections portion
of dodata. Introduce some new helper routines to be used for common
cases in creating sections and assigning symbols, with a goal of
reducing duplicated code blocks and having more readable code.
cmd/go/internal/modfetch: add Unlock before return in checkModSum
In cmd/go/internal/modfetch/fetch.go,
`checkModSum()` forgets Unlock before return, which may lead to deadlock.
https://github.com/golang/go/blob/876c1feb7d5e10a6ff831de9db19b9ff0ea92fa8/src/cmd/go/internal/modfetch/fetch.go#L514-L520
The fix is to add `goSum.mu.Unlock()` before return.
Change-Id: I855b1c1bc00aeada2c1e84aabb5328f02823007d
GitHub-Last-Rev: afeb3763dd1d08c4c15c4c4183fd5705da60dc4c
GitHub-Pull-Request: golang/go#38563
Reviewed-on: https://go-review.googlesource.com/c/go/+/229219
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Jay Conrod <jayconrod@google.com>
Rohith Ravi [Sun, 19 Apr 2020 02:21:15 +0000 (02:21 +0000)]
cmd/trace: fix the broken link in region pages and improve UX
The trace tool had a broken link due to a parameter encoding error,
which has been corrected.
In addition:
- the user regions page has been enhanced to include links to
pprof style profiles for region specific io, block, syscall and
schedwait profiles.
- sortable table headers have a pointer cursor to indicate they're
clickable.
Fixes #38518
Change-Id: I26cd5157bd9753750f5f53ea03aac5d2d41b021c
Reviewed-on: https://go-review.googlesource.com/c/go/+/228899 Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
[dev.link] cmd/link: convert symtab pass to new style
This is more or less a direct translation, to get things going.
There are more things we can do to make it better, especially on
the handling of container symbols.
Change-Id: I11a0087e402be8d42b9d06869385ead531755272
Reviewed-on: https://go-review.googlesource.com/c/go/+/229125
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Jeremy Faller <jeremy@golang.org>
Richard Miller [Tue, 21 Apr 2020 10:00:53 +0000 (11:00 +0100)]
os: correct bad PathError message from FileOpen with O_CREATE on Plan 9
On Plan 9, FileOpen with flag O_CREATE & ~O_TRUNC is done in two
steps. First, syscall.Open is attempted, to avoid truncation when opening
an existing file. If that fails because the file doesn't exist,
syscall.Create is used to create a new file. If the Create fails,
for example because we are racing with another process to create a
ModeExclusive file, the PathError returned from FileOpen should reflect
the result of the Create, not the "does not exist" error from the initial
Open attempt.
Fixes #38540
Change-Id: I90c95a301de417ecdf79cd52748591edb1dbf528
Reviewed-on: https://go-review.googlesource.com/c/go/+/229099
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David du Colombier <0intro@gmail.com>
This is the second attempt. The first attempt was CL 229127,
which got rolled back by CL 229177, because it caused
an infinite loop during compilation on some platforms.
I didn't notice that the trybots hadn't completed when I submitted; mea culpa.
The bug was that we were checking x&(x-1)==0, which is also true of 0,
which does not have exactly one bit set.
This caused an infinite rewrite rule loop.
Matthew Dempsky [Sun, 19 Apr 2020 20:59:16 +0000 (13:59 -0700)]
reflect: disallow invoking methods on unexported embedded fields
Given:
type u struct{}
func (u) M() {}
type t struct { u; u2 u }
var v = reflect.ValueOf(t{})
Package reflect allows:
v.Method(0) // v.M
v.Field(0).Method(0) // v.u.M
but panics from:
v.Field(1).Method(0) // v.u2.M
because u2 is not an exported field. However, u is not an exported
field either, so this is inconsistent.
It seems like this behavior originates from #12367, where it was
decided to allow traversing unexported embedded fields to be able to
access their exported fields, since package reflect doesn't provide an
alternative way to access promoted fields directly.
But extending that logic to promoted *methods* was inappropriate,
because package reflect's normal method handling logic already handles
promoted methods correctly. This CL corrects that mistake.
Fixes #38521.
Change-Id: If65008965f35927b4e7927cddf8614695288eb19
Reviewed-on: https://go-review.googlesource.com/c/go/+/228902
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
cmd/compile: use proper magnitude for (x>>c) & uppermask = 0
This is followup of CL 228860, which rewrite shift rules to use typed
aux. That CL introduced nlz* functions, to refactor left shift rules.
While at it, we realize there's a bug in old rules with both right/left
shift rules, but only fix for left shift rules only.
Change-Id: Ic95f6f78fa56169998a6890beb873693852c5798
Reviewed-on: https://go-review.googlesource.com/c/go/+/228419 Reviewed-by: Ian Lance Taylor <iant@golang.org>
cmd/compile: use oneBit instead of isPowerOfTwo in bit optimization
This optimization works on any integer with exactly one bit set.
This is identical to being a power of two, except in the
most negative number. Use oneBit instead.
The rule now triggers in a few more places in std+cmd,
in packages encoding/asn1, crypto/elliptic, and
vendor/golang.org/x/crypto/cryptobyte.
This change obviates the need for CL 222479
by doing this optimization consistently in the compiler.