Consider these functions:
func f(a any) int
func g(a any) int
Prior to this change, since f and g have identical signatures,
they would share a single generated func type.
types.SubstAny makes a shallow type copy, even after instantiation,
f and g share a single generated Result type.
So if you instantiate f with any=T, call dowidth,
instantiate g with any=U, and call dowidth,
and if sizeof(T) != sizeof(U),
then the Offset of the result for f is now wrong.
I don't believe this happens at all right now, but it bit me hard when
experimenting with some other compiler changes.
And it's hard to debug. It results in rare stack corruption, causing
problems far from the actual source of the problem.
To fix this, change SubstAny to make deep copies of TSTRUCTs.
name old alloc/op new alloc/op delta
Template 35.3MB ± 0% 35.4MB ± 0% +0.23% (p=0.008 n=5+5)
Unicode 29.1MB ± 0% 29.1MB ± 0% +0.16% (p=0.008 n=5+5)
GoTypes 122MB ± 0% 122MB ± 0% +0.16% (p=0.008 n=5+5)
Compiler 513MB ± 0% 514MB ± 0% +0.19% (p=0.008 n=5+5)
SSA 1.94GB ± 0% 1.94GB ± 0% +0.01% (p=0.008 n=5+5)
Flate 24.2MB ± 0% 24.2MB ± 0% +0.08% (p=0.008 n=5+5)
GoParser 28.5MB ± 0% 28.5MB ± 0% +0.24% (p=0.008 n=5+5)
Reflect 86.2MB ± 0% 86.3MB ± 0% +0.09% (p=0.008 n=5+5)
Tar 34.9MB ± 0% 34.9MB ± 0% +0.13% (p=0.008 n=5+5)
XML 47.0MB ± 0% 47.1MB ± 0% +0.18% (p=0.008 n=5+5)
[Geo mean] 80.9MB 81.0MB +0.15%
name old allocs/op new allocs/op delta
Template 348k ± 0% 349k ± 0% +0.38% (p=0.008 n=5+5)
Unicode 340k ± 0% 340k ± 0% +0.21% (p=0.008 n=5+5)
GoTypes 1.27M ± 0% 1.28M ± 0% +0.27% (p=0.008 n=5+5)
Compiler 4.90M ± 0% 4.92M ± 0% +0.36% (p=0.008 n=5+5)
SSA 15.3M ± 0% 15.3M ± 0% +0.03% (p=0.008 n=5+5)
Flate 232k ± 0% 233k ± 0% +0.14% (p=0.008 n=5+5)
GoParser 291k ± 0% 292k ± 0% +0.42% (p=0.008 n=5+5)
Reflect 1.05M ± 0% 1.05M ± 0% +0.14% (p=0.008 n=5+5)
Tar 343k ± 0% 344k ± 0% +0.22% (p=0.008 n=5+5)
XML 428k ± 0% 430k ± 0% +0.36% (p=0.008 n=5+5)
[Geo mean] 807k 809k +0.25%
Change-Id: I62134db642206cded01920dc1d8a7da61f7ca0ac
Reviewed-on: https://go-review.googlesource.com/c/147038
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This change cleans up references to MSpan, MCache, and MCentral in the
docs via a bunch of sed invocations to better reflect the Go names for
the equivalent structures (i.e. mspan, mcache, mcentral) and their
methods (i.e. MSpan_Sweep -> mspan.sweep).
Change-Id: Ie911ac975a24bd25200a273086dd835ab78b1711
Reviewed-on: https://go-review.googlesource.com/c/147557
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
TestTracebackAncestors has a ~0.1% chance of failing with more
goroutines in the traceback than expected. This happens because
there's a window between each goroutine starting its child and that
goroutine actually exiting. The test captures its own stack trace
after everything is "done", but if this happens during that window, it
will include the goroutine that's in the process of being torn down.
Here's an example of such a failure:
https://build.golang.org/log/fad10d0625295eb79fa879f53b8b32b9d0596af8
This CL fixes this by recording the goroutines that are expected to
exit and removing them from the stack trace. With this fix, this test
passed 15,000 times with no failures.
Change-Id: I71e7c6282987a15e8b74188b9c585aa2ca97cbcd
Reviewed-on: https://go-review.googlesource.com/c/147517
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This documentation example was broken:
https://golang.org/pkg/image/png/#example_Decode.
It did not have the "io" package imported,
The package was referenced in the result type of the function.
The "playExample" function did not inspect
the result types of declared functions.
This CL adds inspecting of parameters and result types of functions.
Fixes#28492
Updates #9679
Change-Id: I6d8b11bad2db8ea8ba69039cfaa914093bdd5132
Reviewed-on: https://go-review.googlesource.com/c/146118
Run-TryBot: Yury Smolsky <yury@smolsky.by>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This change re-introduces (temporarily) a work-around for recursive
alias type declarations, originally in https://golang.org/cl/35831/
(intended as fix for #18640). The work-around was removed later
for a more comprehensive cycle detection check. That check
contained a subtle error which made the code appear to work,
while in fact creating incorrect types internally. See #25838
for details.
By re-introducing the original work-around, we eliminate problems
with many simple recursive type declarations involving aliases;
specifically cases such as #27232 and #27267. However, the more
general problem remains.
This CL also fixes the subtle error (incorrect variable use when
analyzing a type cycle) mentioned above and now issues a fatal
error with a reference to the relevant issue (rather than crashing
later during the compilation). While not great, this is better
than the current status. The long-term solution will need to
address these cycles (see #25838).
As a consequence, several old test cases are not accepted anymore
by the compiler since they happened to work accidentally only.
This CL disables parts or all code of those test cases. The issues
are: #18640, #23823, and #24939.
One of the new test cases (fixedbugs/issue27232.go) exposed a
go/types issue. The test case is excluded from the go/types test
suite and an issue was filed (#28576).
Updates #18640.
Updates #23823.
Updates #24939.
Updates #25838.
Updates #28576.
Fixes#27232.
Fixes#27267.
Change-Id: I6c2d10da98bfc6f4f445c755fcaab17fc7b214c5
Reviewed-on: https://go-review.googlesource.com/c/147286
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
As of 07e738e all spans are allocated out of a treap, and not just
large spans or spans for large objects. Also, now we have a separate
treap for spans that have been scavenged.
Change-Id: I9c2cb7b6798fc536bbd34835da2e888224fd7ed4
Reviewed-on: https://go-review.googlesource.com/c/142958
Reviewed-by: Austin Clements <austin@google.com>
This uses the mutator utilization distribution to compute the p99.9,
p99, and p95 mutator utilization topograph lines and display them
along with the MMU.
Change-Id: I8c7e0ec326aa4bc00619ec7562854253f01cc802
Reviewed-on: https://go-review.googlesource.com/c/60800
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
This adds support for computing the quantiles of a mutator utilization
distribution.
Change-Id: Ia8b3ed14bf415c234e2f567360fd1b361d28bd40
Reviewed-on: https://go-review.googlesource.com/c/60799
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
The current MMU analysis considers all Ps together, so if, for
example, one of four Ps is blocked, mutator utilization is 75%.
However, this is less useful for understanding the impact on
individual goroutines because that one blocked goroutine could be
blocked for a very long time, but we still appear to have good
utilization.
Hence, this introduces a new flag that does a "per-P" analysis where
the utilization of each P is considered independently. The MMU is then
the combination of the MMU for each P's utilization function.
Change-Id: Id67b980d4d82b511d28300cdf92ccbb5ae8f0c78
Reviewed-on: https://go-review.googlesource.com/c/60797
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
This adds the ability to click a point on the MMU graph to show a list
of the worst 10 mutator utilization windows of the selected size. This
list in turn links to the trace viewer to drill down on specifically
what happened in each specific window.
Change-Id: Ic1b72d8b37fbf2212211c513cf36b34788b30133
Reviewed-on: https://go-review.googlesource.com/c/60795
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This will let the trace viewer show specifically when poor utilization
happened and link to specific instances in the trace.
Change-Id: I1f03a0f9d9a7570009bb15762e7b8b6f215e9423
Reviewed-on: https://go-review.googlesource.com/c/60793
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
This further optimizes MMU construction by first computing a
low-resolution summary of the utilization curve. This "band" summary
lets us compute the worst-possible window starting in each of these
low-resolution bands (even without knowing where in the band the
window falls). This in turn lets us compute precise minimum mutator
utilization only in the worst low-resolution bands until we can show
that any remaining bands can't possibly contain a worse window.
This slows down MMU construction for small traces, but these are
reasonably fast to compute either way. For large traces (e.g.,
150,000+ utilization changes) it's significantly faster.
Change-Id: Ie66454e71f3fb06be3f6173b6d91ad75c61bda48
Reviewed-on: https://go-review.googlesource.com/c/60792
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
This commit speeds up MMU construction by ~10X (and reduces the number
of windows considered by ~20X) by using an observation about the
maximum slope of the windowed mutator utilization function to advance
the window time in jumps if the window's current mean mutator
utilization is much larger than the current minimum.
Change-Id: If3cba5da0c4adc37b568740f940793e491e96a51
Reviewed-on: https://go-review.googlesource.com/c/60791
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
This adds an endpoint to the trace tool that plots the minimum mutator
utilization curve using information on mark assists and GC pauses from
the trace.
This commit implements a fairly straightforward O(nm) algorithm for
computing the MMU (and tests against an even more direct but slower
algorithm). Future commits will extend and optimize this algorithm.
This should be useful for debugging and understanding mutator
utilization issues like #14951, #14812, #18155. #18534, #21107,
particularly once follow-up CLs add trace cross-referencing.
Change-Id: Ic2866869e7da1e6c56ba3e809abbcb2eb9c4923a
Reviewed-on: https://go-review.googlesource.com/c/60790
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
zgoos_aix.go is missing GoosJs, the order of GoosAndroid and GoosAix is
mixed up in all files and GoosHurd was added after CL 146023 introduced
GOOS=hurd.
Change-Id: I7e2f5a15645272e9020cfca86e44c364fc072a2b
Reviewed-on: https://go-review.googlesource.com/c/147397
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The kernel on some Samsung S9+ models reports support for arm64 8.1
atomics, but in reality only some of the cores support them. Go
programs scheduled to cores without support will crash with SIGILL.
This change unconditionally disables the optimization on Android.
A better fix is to precisely detect the offending chipset.
Fixes#28431
Change-Id: I35a1273e5660603824d30ebef2ce7e429241bf1f
Reviewed-on: https://go-review.googlesource.com/c/147377
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
At each comparison, we're making a copy of the whole string.
Instead, use unsafe to share the string backing store with a []byte.
It reduces the test time from ~4sec to ~1sec on my machine
(darwin/amd64). Some builders were having much more trouble with this
test (>3min), it may help more there.
Fixes#26174Fixes#28573Fixes#26155
Update #26473
Change-Id: Id5856fd26faf6ff46e763a088f039230556a4116
Reviewed-on: https://go-review.googlesource.com/c/147358
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Was only ever filled with one Etype (TFORW) and only used
in one place. Easier to just check for TFORW.
Change-Id: Icc96da3a22b0af1d7e60bc5841c744916c53341e
Reviewed-on: https://go-review.googlesource.com/c/147285
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
The Fatalf mechanism already prints "compiler internal error:"
when reporting an error. There's no need to have "internal error"
in the error message passed to Fatalf calls. Removed them.
Fixes#28575.
Change-Id: I12b1bea37bc839780f257c27ef9e2005bf334925
Reviewed-on: https://go-review.googlesource.com/c/147287
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Currently, WriteObjFile deduplicates symbols by name. This is a
strange and unexpected place to do this. But, worse, there's no
checking that it's reasonable to deduplicate two symbols, so this
makes it incredibly easy to mask errors involving duplicate symbols.
Dealing with duplicate symbols is better left to the linker. We're
also about to introduce multiple symbols with the same name but
different ABIs/versions, which would make this deduplication more
complicated. We just removed the only part of the compiler that
actually depended on this behavior.
This CL removes symbol deduplication from WriteObjFile, since it is no
longer needed.
For #27539.
Change-Id: I650c550e46e83f95c67cb6c6646f9b2f7f10df30
Reviewed-on: https://go-review.googlesource.com/c/146558
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Currently, liveness produces a distinct obj.LSym for each GC bitmap
for each function. These are then named by content hash and only
ultimately deduplicated by WriteObjFile.
For various reasons (see next commit), we want to remove this
deduplication behavior from WriteObjFile. Furthermore, it's
inefficient to produce these duplicate symbols in the first place.
GC bitmaps are the only source of duplicate symbols in the compiler.
This commit eliminates these duplicate symbols by declaring them in
the Ctxt symbol hash just like every other obj.LSym. As a result, all
GC bitmaps with the same content now refer to the same obj.LSym.
The next commit will remove deduplication from WriteObjFile.
For #27539.
Change-Id: I4f15e3d99530122cdf473b7a838c69ef5f79db59
Reviewed-on: https://go-review.googlesource.com/c/146557
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
32-bit negated logical instructions (BICW, ORNW, EONW) with
constants were mis-encoded, because they were missing in the
cases where we handle 32-bit logical instructions. This CL
adds the missing cases.
Fixes#28548
Change-Id: I3d6acde7d3b72bb7d3d5d00a9df698a72c806ad5
Reviewed-on: https://go-review.googlesource.com/c/147077
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Ben Shi <powerman1st@163.com>
Reviewed-by: Ben Shi <powerman1st@163.com>
Scanning through all path patterns is not necessary, since the
paths do not change frequently. Instead, maintain a sorted list
of path prefixes and return the first match.
name old time/op new time/op delta
ServerMatch-12 134ns ± 3% 17ns ± 4% -86.95% (p=0.000 n=19+20)
Change-Id: I15b4483dc30db413321435ee6815fc9bf2bcc546
Reviewed-on: https://go-review.googlesource.com/c/144937
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Go documentation style for boolean funcs is to say:
// Foo reports whether ...
func Foo() bool
(rather than "returns true if")
This CL also replaces 4 uses of "iff" with the same "reports whether"
wording, which doesn't lose any meaning, and will prevent people from
sending typo fixes when they don't realize it's "if and only if". In
the past I think we've had the typo CLs updated to just say "reports
whether". So do them all at once.
(Inspired by the addition of another "returns true if" in CL 146938
in fd_plan9.go)
Created with:
$ perl -i -npe 's/returns true if/reports whether/' $(git grep -l "returns true iff" | grep -v vendor)
$ perl -i -npe 's/returns true if/reports whether/' $(git grep -l "returns true if" | grep -v vendor)
Change-Id: Ided502237f5ab0d25cb625dbab12529c361a8b9f
Reviewed-on: https://go-review.googlesource.com/c/147037
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The compiler must first be built with the constant enableTrace set
to true (typecheck.go). After that, the -t flag becomes available
which enables tracing output of type-checking functions.
With enableTrace == false, the tracing code becomes dead code
and won't affect the compiler.
Typical output might look like this:
path/y.go:4:6: typecheck 0xc00033e180 DCLTYPE <node DCLTYPE> tc=0
path/y.go:4:6: . typecheck1 0xc00033e180 DCLTYPE <node DCLTYPE> tc=2
path/y.go:4:6: . . typecheck 0xc000331a40 TYPE T tc=1
path/y.go:4:6: . . . typecheck1 0xc000331a40 TYPE T tc=2
path/y.go:4:6: . . . . typecheckdef 0xc000331a40 TYPE T tc=2
path/y.go:4:6: . . . . => 0xc000331a40 TYPE T tc=2 type=*T
path/y.go:4:6: . . . => 0xc000331a40 TYPE T tc=2 type=*T
path/y.go:4:6: . . => 0xc000331a40 TYPE T tc=1 type=*T
path/y.go:4:6: . => 0xc00033e180 DCLTYPE <node DCLTYPE> tc=2 type=<T>
path/y.go:4:6: => 0xc00033e180 DCLTYPE <node DCLTYPE> tc=1 type=<T>
Disabled by default.
Change-Id: Ifd8385290d1cf0d3fc5e8468b2f4ab84e8eff338
Reviewed-on: https://go-review.googlesource.com/c/146782
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Implement a basic TLS 1.3 server handshake, only enabled if explicitly
requested with MaxVersion.
This CL intentionally leaves for future CLs:
- PSK modes and resumption
- client authentication
- compatibility mode ChangeCipherSpecs
- early data skipping
- post-handshake messages
- downgrade protection
- KeyLogWriter support
- TLS_FALLBACK_SCSV processing
It also leaves a few areas up for a wider refactor (maybe in Go 1.13):
- the certificate selection logic can be significantly improved,
including supporting and surfacing signature_algorithms_cert, but
this isn't new in TLS 1.3 (see comment in processClientHello)
- handshake_server_tls13.go can be dried up and broken into more
meaningful, smaller functions, but it felt premature to do before
PSK and client auth support
- the monstrous ClientHello equality check in doHelloRetryRequest can
get both cleaner and more complete with collaboration from the
parsing layer, which can come at the same time as extension
duplicates detection
Updates #9671
Change-Id: Id9db2b6ecc2eea21bf9b59b6d1d9c84a7435151c
Reviewed-on: https://go-review.googlesource.com/c/147017
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
crypto/x509 already supports PSS signatures (with rsaEncryption OID),
and crypto/tls support was added in CL 79736. Advertise support for the
algorithms and accept them as a peer.
Note that this is about PSS signatures from regular RSA public keys.
RSA-PSS only public keys (with RSASSA-PSS OID) are supported in neither
crypto/tls nor crypto/x509. See RFC 8446, Section 4.2.3.
testdata/Server-TLSv12-ClientAuthRequested* got modified because the
CertificateRequest carries the supported signature algorithms.
The net/smtp tests changed because 512 bits keys are too small for PSS.
Based on Peter Wu's CL 79738, who did all the actual work in CL 79736.
Updates #9671
Change-Id: I4a31e9c6e152ff4c50a5c8a274edd610d5fff231
Reviewed-on: https://go-review.googlesource.com/c/146258
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
RFC 8446 recommends using the supported_versions extension to negotiate
lower versions as well, so begin by implementing it to negotiate the
currently supported versions.
Note that pickTLSVersion was incorrectly negotiating the ServerHello
version down on the client. If the server had illegally sent a version
higher than the ClientHello version, the client would have just
downgraded it, hopefully failing later in the handshake.
In TestGetConfigForClient, we were hitting the record version check
because the server would select TLS 1.1, the handshake would fail on the
client which required TLS 1.2, which would then send a TLS 1.0 record
header on its fatal alert (not having negotiated a version), while the
server would expect a TLS 1.1 header at that point. Now, the client gets
to communicate the minimum version through the extension and the
handshake fails on the server.
Updates #9671
Change-Id: Ie33c7124c0c769f62e10baad51cbed745c424e5b
Reviewed-on: https://go-review.googlesource.com/c/146217
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>
Note that there is significant code duplication due to extensions with
the same format appearing in different messages in TLS 1.3. This will be
cleaned up in a future refactor once CL 145317 is merged.
Enforcing the presence/absence of each extension in each message is left
to the upper layer, based on both protocol version and extensions
advertised in CH and CR. Duplicated extensions and unknown extensions in
SH, EE, HRR, and CT will be tightened up in a future CL.
The TLS 1.2 CertificateStatus message was restricted to accepting only
type OCSP as any other type (none of which are specified so far) would
have to be negotiated.
Updates #9671
Change-Id: I7c42394c5cc0af01faa84b9b9f25fdc6e7cfbb9e
Reviewed-on: https://go-review.googlesource.com/c/145477
Reviewed-by: Adam Langley <agl@golang.org>
Unlikely to happen in practice, but easy enough to prevent and might
as well do so for completeness.
Fixes#28243.
Change-Id: I848c3af49cb923f088e9490c6a79373e182fad08
Reviewed-on: https://go-review.googlesource.com/c/142719
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Austin Clements <austin@google.com>
There are some OpenGL functions that take more than 15 arguments.
This CL adds Syscall18 to enable to call such functions on Windows
via syscall functions.
Fixes#28434
Change-Id: Ic7e37dda9cadf4516183e98166bfc52844ad2bbe
Reviewed-on: https://go-review.googlesource.com/c/147117
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>