This is a fully backward-compatible language change.
There are not a lot of cases in the std library, but
there are some. Arguably this makes the syntax a bit
more regular - any trailing index variable that is _
can be left away, and there's some analogy to type
switches where the temporary can be left away.
Implementation-wise the change should be trivial as
it can be done completely syntactically. For instance,
the respective change in go/parser is a dozen lines
(see https://golang.org/cl/112970044 ).
Fixes#6102.
LGTM=iant, r, rsc
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/104680043
The runtime has historically held two dedicated values g (current goroutine)
and m (current thread) in 'extern register' slots (TLS on x86, real registers
backed by TLS on ARM).
This CL removes the extern register m; code now uses g->m.
On ARM, this frees up the register that formerly held m (R9).
This is important for NaCl, because NaCl ARM code cannot use R9 at all.
The Go 1 macrobenchmarks (those with per-op times >= 10 µs) are unaffected:
BenchmarkBinaryTree17 5491374955 5471024381 -0.37%
BenchmarkFannkuch11 4357101311 4275174828 -1.88%
BenchmarkGobDecode 11029957 11364184 +3.03%
BenchmarkGobEncode 6852205 6784822 -0.98%
BenchmarkGzip 650795967 650152275 -0.10%
BenchmarkGunzip 140962363 141041670 +0.06%
BenchmarkHTTPClientServer 71581 73081 +2.10%
BenchmarkJSONEncode 31928079 31913356 -0.05%
BenchmarkJSONDecode 117470065 113689916 -3.22%
BenchmarkMandelbrot200 6008923 5998712 -0.17%
BenchmarkGoParse 6310917 6327487 +0.26%
BenchmarkRegexpMatchMedium_1K 114568 114763 +0.17%
BenchmarkRegexpMatchHard_1K 168977 169244 +0.16%
BenchmarkRevcomp 935294971 914060918 -2.27%
BenchmarkTemplate 145917123 148186096 +1.55%
Minux previous reported larger variations, but these were caused by
run-to-run noise, not repeatable slowdowns.
Actual code changes by Minux.
I only did the docs and the benchmarking.
LGTM=dvyukov, iant, minux
R=minux, josharian, iant, dave, bradfitz, dvyukov
CC=golang-codereviews
https://golang.org/cl/109050043
This CL removes the special syntax for method receivers and
makes it just like other parameters. Instead, the crucial
receiver-specific rules (exactly one receiver, receiver type
must be of the form T or *T) are specified verbally instead
of syntactically.
This is a fully backward-compatible (and minor) syntax
relaxation. As a result, the following syntactic restrictions
(which are completely irrelevant) and which were only in place
for receivers are removed:
a) receiver types cannot be parenthesized
b) receiver parameter lists cannot have a trailing comma
The result of this CL is a simplication of the spec and the
implementation, with no impact on existing (or future) code.
Noteworthy:
- gc already permits a trailing comma at the end of a receiver
declaration:
func (recv T,) m() {}
This is technically a bug with the current spec; this CL will
legalize this notation.
- gccgo produces a misleading error when a trailing comma is used:
error: method has multiple receivers
(even though there's only one receiver)
- Compilers and type-checkers won't need to report errors anymore
if receiver types are parenthesized.
Fixes#4496.
LGTM=iant, rsc
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/101500044
This is a clone of 101370043, which I accidentally applied to the
release branch first.
No big deal, it needed to be applied there anyway.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/108090043
The current wording is reversed in 2 places.
Not sure how it got 4 LGTMs (mine was there as well).
Update #6242.
LGTM=dan.kortschak, r, rsc
R=golang-codereviews, 0xjnml, dan.kortschak, r, rsc
CC=golang-codereviews
https://golang.org/cl/101980047
For incomplete struct S, C.T and C.struct_S were interchangeable in Go 1.2
and earlier, because all incomplete types were interchangeable
(even C.struct_S1 and C.struct_S2).
CL 76450043, which fixed issue 7409, made different incomplete types
different from Go's point of view, so that they were no longer completely
interchangeable.
However, imprecision about C.T and C.struct_S - really the same
underlying C type - is the one behavior enabled by the bug that
is most likely to be depended on by existing cgo code.
Explicitly allow it, to keep that code working.
Fixes#7786.
LGTM=iant, r
R=golang-codereviews, iant, r
CC=golang-codereviews
https://golang.org/cl/98580046
Also made it extra clear for goto statements (even though label scopes
are already limited to the function defining a label).
Fixes#8040.
LGTM=r, rsc
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/99550043
The spec was unclear about whether blank methods should be
permitted in interface types. gccgo permits at most one, gc
crashes if there are more than one, go/types permits at most
one.
Discussion:
Since method sets of non-interface types never contain methods
with blank names (blank methods are never declared), it is impossible
to satisfy an interface with a blank method.
It is possible to declare variables of assignable interface types
(but not necessarily identical types) containing blank methods, and
assign those variables to each other, but the values of those
variables can only be nil.
There appear to be two "reasonable" alternatives:
1) Permit at most one blank method (since method names must be unique),
and consider it part of the interface. This is what appears to happen
now, with corner-case bugs. Such interfaces can never be implemented.
2) Permit arbitrary many blank methods but ignore them. This appears
to be closer to the handling of blank identifiers in declarations.
However, an interface type literal is not a declaration (it's a type
literal). Also, for struct types, blank identifiers are not ignored;
so the analogy with declarations is flawed.
Both these alternatives don't seem to add any benefit and are likely
(if only slightly) more complicated to explain and implement than
disallowing blank methods in interfaces altogether.
Fixes#6604.
LGTM=r, rsc, iant
R=r, rsc, ken, iant
CC=golang-codereviews
https://golang.org/cl/99410046
The key property here is what the bit pattern represents,
not what its type is. Storing 5 into a pointer is the problem.
Storing a uintptr that holds pointer bits back into a pointer
is not as much of a problem, and not what we are claiming
the runtime will detect.
Longer discussion at
https://groups.google.com/d/msg/golang-nuts/dIGISmr9hw0/0jO4ce85Eh0J
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/98370045
The spec did not specify the order in which
init() functions are called. Specify that
they are called in source order since we have
now also specified the initialization order
of independent variables.
While technically a language change, no
existing code could have relied on this,
so this should not break anything.
Per suggestion from rsc.
LGTM=r, iant
R=rsc, iant, r, ken
CC=golang-codereviews
https://golang.org/cl/98420046
- split description of package initialization and
program execution
- better grouping of concerns in section on package
initialization
- more explicit definition of what constitues a
dependency
- removed language about constant dependencies -
they are computed at compile-time and not
initialized at run-time
- clarified that independent variables are initialized
in declaration order (rather than reference order)
Note that the last clarification is what distinguishes
gc and gccgo at the moment: gc uses reference order
(i.e., order in which variables are referenced in
initialization expressions), while gccgo uses declaration
order for independent variables.
Not a language change. But adopting this CL will
clarify what constitutes a dependency.
Fixes#6703.
LGTM=adonovan, r, iant, rsc
R=r, rsc, iant, ken, adonovan
CC=golang-codereviews
https://golang.org/cl/99020043
The move from 4kB to 8kB in Go 1.2 was to eliminate many stack split hot spots.
The move back to 4kB was predicated on copying stacks eliminating
the potential for hot spots.
Unfortunately, the fact that stacks do not copy 100% of the time means
that hot spots can still happen under the right conditions, and the slowdown
is worse now than it was in Go 1.2. There is a real program in issue 8030 that
sees about a 30x slowdown: it has a reflect call near the top of the stack
which inhibits any stack copying on that segment.
Go back to 8kB until stack copying can be used 100% of the time.
Fixes#8030.
LGTM=khr, dave, iant
R=iant, khr, r, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/92540043
Make it a little clearer how they are used, in particular that
it is not enough just to return a nil pointer on error, but also
to return an error value explaining the problem.
Fixes#1963.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/97360045
- use previously defined terms (with links) throughout
- specify evaluation order more precisely (in particular,
the evaluation time of rhs expressions in receive cases
was not specified)
- added extra example case
Not a language change.
Description matches observed behavior of code compiled
with gc and gccgo.
Fixes#7669.
LGTM=iant, r, rsc
R=r, rsc, iant, ken, josharian
CC=golang-codereviews
https://golang.org/cl/91230043
This change requires using SWIG version 3.0 or later. Earlier
versions of SWIG do not generate the pragmas required to use
the external linker.
Fixes#7155.
Fixes#7156.
LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/97120046
- A channel may be used between any number of goroutines,
not just two.
- Replace "passing a value" (which is not further defined)
by "sending and receiving a value".
- Made syntax production more symmetric.
- Talk about unbuffered channels before buffered channels.
- Clarify what the comma,ok receive values mean (issue 7785).
Not a language change.
Fixes#7785.
LGTM=rsc, r, iant
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/94030045
This is a clarification of what happens already.
Not a language change.
Fixes#7137.
LGTM=iant, r, rsc
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/96000044
If the underlying type of a type T is a boolean, numeric,
or string type, then T is also a boolean, numeric, or
string type, respectively.
Not a language change.
Fixes#7551.
LGTM=iant, rsc, robert.hencke, r
R=r, rsc, iant, ken, robert.hencke
CC=golang-codereviews
https://golang.org/cl/100130044
Currently tip.golang.org leads to golang.org and
local godoc also leads to golang.org (when you don't have internet connectivity).
LGTM=crawshaw
R=golang-codereviews, crawshaw
CC=golang-codereviews
https://golang.org/cl/100200043
We will serve downloads from here until we work out a better plan.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/95980044
The instructions in this document are useful but not reliable.
Explain the situation up top.
Fixes#7471.
LGTM=josharian, iant
R=golang-codereviews, josharian, iant
CC=golang-codereviews
https://golang.org/cl/96830045
The rewrite is due to Rob.
LGTM=r, bradfitz, josharian
R=golang-codereviews, bradfitz, r, josharian
CC=golang-codereviews
https://golang.org/cl/87410043
This has typically crashed in the past, although usually with
an 'all goroutines are asleep - deadlock!' message that shows
no goroutines (because there aren't any).
Previous discussion at:
https://groups.google.com/d/msg/golang-nuts/uCT_7WxxopQ/BoSBlLFzUTkJhttps://groups.google.com/d/msg/golang-dev/KUojayEr20I/u4fp_Ej5PdUJhttp://golang.org/issue/7711
There is general agreement that runtime.Goexit terminates the
main goroutine, so that main cannot return, so the program does
not exit.
The interpretation that all other goroutines exiting causes an
exit(0) is relatively new and was not part of those discussions.
That is what this CL changes.
Thankfully, even though the exit(0) has been there for a while,
some other accounting bugs made it very difficult to trigger,
so it is reasonable to replace. In particular, see golang.org/issue/7711#c10
for an examination of the behavior across past releases.
Fixes#7711.
LGTM=iant, r
R=golang-codereviews, iant, dvyukov, r
CC=golang-codereviews
https://golang.org/cl/88210044
If we compile a generated file stored in a temporary
directory - let's say /tmp/12345/work/x.c - then by default
6c stores the full path and then the pcln table in the
final binary includes the full path. This makes repeated builds
(using different temporary directories) produce different
binaries, even if the inputs are the same.
In the old 'go tool pack', the P flag specified a prefix to remove
from all stored paths (if present), and cmd/go invoked
'go tool pack grcP $WORK' to remove references to the
temporary work directory.
We've changed the build to avoid pack as much as possible,
under the theory that instead of making pack convert from
.6 to .a, the tools should just write the .a directly and save a
round of I/O.
Instead of going back to invoking pack always, define a common
flag -trimpath in the assemblers, C compilers, and Go compilers,
implemented in liblink, and arrange for cmd/go to use the flag.
Then the object files being written out have the shortened paths
from the start.
While we are here, reimplement pcln support for GOROOT_FINAL.
A build in /tmp/go uses GOROOT=/tmp/go, but if GOROOT_FINAL=/usr/local/go
is set, then a source file named /tmp/go/x.go is recorded instead as
/usr/local/go/x.go. We use this so that we can prepare distributions
to be installed in /usr/local/go without actually working in that
directory. The conversion to liblink deleted all the old file name
handling code, including the GOROOT_FINAL translation.
Bring the GOROOT_FINAL translation back.
Before this CL, using GOROOT_FINAL=/goroot make.bash:
g% strings $(which go) | grep -c $TMPDIR
6
g% strings $(which go) | grep -c $GOROOT
793
g%
After this CL:
g% strings $(which go) | grep -c $TMPDIR
0
g% strings $(which go) | grep -c $GOROOT
0
g%
(The references to $TMPDIR tend to be cgo-generated source files.)
Adding the -trimpath flag to the assemblers required converting
them to the new Go-semantics flag parser. The text in go1.3.html
is copied and adjusted from go1.1.html, which is when we applied
that conversion to the compilers and linkers.
Fixes#6989.
LGTM=iant
R=r, iant
CC=golang-codereviews
https://golang.org/cl/88300045
Also make it clear this is not a complete description of all features.
Fixes#7790.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/88300044
All that's left is net/http and the stuff I need help describing: FreeBSD and Windows.
LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/86320043
Almost all TODOS, but the structure is there and it has the details
from go1.3.txt, which is hereby deleted.
LGTM=dominik.honnef, adg
R=golang-codereviews, dominik.honnef, adg
CC=golang-codereviews
https://golang.org/cl/80240044
This rule not existing has been the source of many discussions
on golang-dev and on issues. We have stated publicly that it is
true, but we have never written it down. Write it down.
Fixes#6242.
LGTM=r, dan.kortschak, iant, dvyukov
R=golang-codereviews, r, dominik.honnef, dvyukov, dan.kortschak, iant, 0xjnml
CC=golang-codereviews
https://golang.org/cl/75130045
They aren't segmented any more, at least with gc.
Also improve the comparison of goroutines and threads.
Fixes#7373.
LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/77950044
Prose referred to 'b', code used 'buf'.
Fixes#7601.
LGTM=dominik.honnef
R=golang-codereviews, dominik.honnef
CC=golang-codereviews
https://golang.org/cl/78470043
The original test would open a local port and then immediately close it
and use the port number in subsequent tests. Between the port being closed
and reused by the later process, it could be opened by some other program
on the machine.
Changed the test to run the server process directly and have it save the
assigned port to a text file to be used by client processes.
Fixes#5564.
LGTM=adg
R=golang-codereviews, gobot, adg
CC=golang-codereviews
https://golang.org/cl/72290043
Smooth out the setup process for new contributors.
* Remove references $GOROOT (often not defined).
* Add a note for contributing to subrepositories.
* Emphasize that hg mail also uploads the latest copy.
LGTM=adg
R=golang-codereviews, iant, adg
CC=golang-codereviews
https://golang.org/cl/74370043
This documents the status quo for most implementations,
with one exception: gc generates a run-time error for
constant but out-of-range indices when slicing a constant
string. See issue 7200 for a detailed discussion.
LGTM=r
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/72160044
The underlying type of the predeclared type error is not itself,
but the interface it is defined as.
Fixes#7444.
LGTM=r, rsc
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/71790044
CLA links are now redirects. Use new URLs instead.
Also, use https:// links for all Google sites where
the http version just redirects to https anyway.
(That's all links on the page, as it turns out)
LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/69980051
This documents the implemented behavior of both
gc and gccgo as an implementation restriction.
NOT A LANGUAGE CHANGE.
Fixes#5425.
LGTM=rsc, r, iant
R=r, iant, rsc, ken
CC=golang-codereviews
https://golang.org/cl/71430043
gccgo considers built-in function calls returning a constant not as function call (issue 7386)
go/types considers any call (regular or built-in) as a function call
The wording and examples clarify that only "function calls" that are issued
at run-time (and thus do not result in a constant result) are considered
function calls in this case.
gc is inconsistent (issue 7385)
gccgo already interprets the spec accordingly and issue 7386 is moot.
go/types considers all calls (constant or not) as function calls (issue 7457).
Fixes#7387.
Fixes#7386.
LGTM=r, rsc, iant
R=r, rsc, iant, ken
CC=golang-codereviews
https://golang.org/cl/66860046
An absent condition/tag in for and switch statements is equivalent
to the predeclared constant true; not simply the expression true
(which might lead to a locally defined true).
Not a language change.
Fixes#7404.
LGTM=iant, r
R=r, iant, rsc, ken
CC=golang-codereviews
https://golang.org/cl/68150046
The new flag was added by CL 68150047 (part of the NaCl replay),
but the change, like the original, omitted documentation of the
new behavior.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/68580043
crypto/tls has two functions for creating a client connection: Dial,
which most users are expected to use, and Client, which is the
lower-level API.
Dial does what you expect: it gives you a secure connection to the host
that you specify and the majority of users of crypto/tls appear to work
fine with it.
Client gives more control but needs more care. Specifically, if it
wasn't given a server name in the tls.Config then it didn't check that
the server's certificates match any hostname - because it doesn't have
one to check against. It was assumed that users of the low-level API
call VerifyHostname on the certificate themselves if they didn't supply
a hostname.
A review of the uses of Client both within Google and in a couple of
external libraries has shown that nearly all of them got this wrong.
Thus, this change enforces that either a ServerName or
InsecureSkipVerify is given. This does not affect tls.Dial.
See discussion at https://groups.google.com/d/msg/golang-nuts/4vnt7NdLvVU/b1SJ4u0ikb0J.
Fixes#7342.
LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/67010043
SetPanicOnFault allows recovery from unexpected memory faults.
This can be useful if you are using a memory-mapped file
or probing the address space of the current program.
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/66590044
Add b.RunParallel function that captures parallel benchmark boilerplate:
creates worker goroutines, joins worker goroutines, distributes work
among them in an efficient way, auto-tunes grain size.
Fixes#7090.
R=bradfitz, iant, josharian, tracey.brendan, r, rsc, gobot
CC=golang-codereviews
https://golang.org/cl/57270043
go/build is changed to list the .m files in a package, and match them for build constraints, adding them to a new field: Package.MFiles.
The go tool is changed to support building .m files and linking in the results during CGO and SWIG builds. This means packages that create a C interface to calls Objective-C code from go are now go-gettable without producing and distributing .syso files. This change is analogous to the one in Go 1.2 made to support C++ built code.
This change doesn't support .mm files (Objective C++).
Also added support for these MFiles to go list's -json mode.
Fixes#6536.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/60590044
This got deleted mistakenly during the content re-org.
Fixes#7275.
LGTM=dvyukov
R=golang-codereviews, minux.ma, dvyukov
CC=golang-codereviews
https://golang.org/cl/60850043
So that we don't need to update the file each time a new version is released.
LGTM=dave, r, adg
R=golang-codereviews, dave, josharian, gobot, adg, r
CC=golang-codereviews
https://golang.org/cl/48730043
Needs to be an h3, not an h2.
Thanks to Mingjie Xing for pointing it out.
LGTM=dsymonds
R=golang-codereviews, dsymonds
CC=golang-codereviews
https://golang.org/cl/55980046
Example of output:
goroutine 4 [sleep for 3 min]:
time.Sleep(0x34630b8a000)
src/pkg/runtime/time.goc:31 +0x31
main.func·002()
block.go:16 +0x2c
created by main.main
block.go:17 +0x33
Full program and output are here:
http://play.golang.org/p/NEZdADI3TdFixes#6809.
R=golang-codereviews, khr, kamil.kisiel, bradfitz, rsc
CC=golang-codereviews
https://golang.org/cl/50420043
No change to the meaning, just bad writing found by
Doug McIlroy.
Let's start the new year off with a bang.
R=golang-codereviews, bradfitz, dave
CC=golang-codereviews
https://golang.org/cl/47110044
