Rémy Oudompheng [Wed, 12 Dec 2012 07:35:08 +0000 (08:35 +0100)]
cmd/6g, cmd/8g: simplify integer division code.
Change suggested by iant. The compiler generates
special code for a/b when a is -0x80...0 and b = -1.
A single instruction can cover the case where b is -1,
so only one comparison is needed.
The code inside the casee and casep labels can perfectly be merged since
they essentially do the same. The character to be stored where cp points is
just the character contained by the c variable.
Brad Fitzpatrick [Tue, 11 Dec 2012 17:07:27 +0000 (12:07 -0500)]
net/http, net/url: permit Request-URI "*"
Also, implement a global OPTIONS * handler, like Apache.
Permit sending "*" requests to handlers, but not path-based
(ServeMux) handlers. That means people can go out of their
way to support SSDP or SIP or whatever, but most users will be
unaffected.
See RFC 2616 Section 5.1.2 (Request-URI)
See RFC 2616 Section 9.2 (OPTIONS)
Robert Griesemer [Mon, 10 Dec 2012 19:55:57 +0000 (11:55 -0800)]
spec: consistently use "indices" (rather than "indexes")
We have been using all three terms "indices", "indexes",
and "index expressions" indiscriminatly for index values.
With this change, "index" refers to an index value,
"indices" is the plural of "index", and "index expression"
refers to an array, slice, or map indexed by an index: a[x].
Russ Cox [Sun, 9 Dec 2012 08:59:33 +0000 (03:59 -0500)]
time: add Round and Truncate
New in Go 1 will be nanosecond precision in the result of time.Now on Linux.
This will break code that stores time in external formats at microsecond
precision, reads it back, and expects to get exactly the same time.
Code like that can be fixed by using time.Now().Round(time.Microsecond)
instead of time.Now() in those contexts.
When giving the same seeds to Go 1.0 and Go 1.1 programs
I would like them to generate the same random numbers.
««« original CL description
math/rand: remove noop iteration in Perm
The first iteration always do `m[0], m[0] = m[0], m[0]`, because
`rand.Intn(1)` is 0.
fun note: IIRC in TAOCP version of this algorithm, `i` goes
backward (n-1->1), meaning that the "already" shuffled part of the
array is never altered betweens iterations, while in the current
implementation the "not-yet" shuffled part of the array is
conserved between iterations.
Robert Griesemer [Thu, 6 Dec 2012 17:17:20 +0000 (09:17 -0800)]
spec: type assertions and type switches must be valid
The spec didn't preclude invalid type assertions and
type switches, i.e., cases where a concrete type doesn't
implement the interface type in the assertion in the first
place. Both, the gc and gccgo compiler exclude these cases.
This is documenting the status quo.
Also:
- minor clean up of respective examples
- added sentence about default case in select statements
Fixes #4472.
R=rsc, iant, r, ken
CC=golang-dev
https://golang.org/cl/6869050
Rémy Oudompheng [Thu, 6 Dec 2012 06:20:03 +0000 (07:20 +0100)]
cmd/6c, cmd/8c: add fixjmp step to regopt.
The fixjmp step eliminates redundant chains of JMP
instructions that are produced by the compiler during
code generation.
It is already implemented in gc, and can be adapted to 6c/8c with
the exception that JMPs refer to destination by pc instead of by
pointer. The algorithm is modified to operate on Regs instead of Progs
for this reason. The pcs are already restored later by regopt.
Russ Cox [Thu, 6 Dec 2012 05:00:20 +0000 (00:00 -0500)]
cmd/ld: skip 0-length write in cwrite
The 0-length part is fine, but some callers that write 0 bytes
also pass nil as the data pointer, and the Plan 9 kernel kills the
process with 'invalid address in sys call' in that case.
Brad Fitzpatrick [Thu, 6 Dec 2012 03:08:42 +0000 (19:08 -0800)]
net/http: fix bug parsing http_proxy lacking a protocol
Per the curl man page, the http_proxy configuration can be
of the form:
[protocol://]<host>[:port]
And we had a test that <ip>:<port> worked, but if
the host began with a letter, url.Parse parsed the hostname
as the scheme instead, confusing ProxyFromEnvironment.
Dave Cheney [Wed, 5 Dec 2012 21:01:33 +0000 (08:01 +1100)]
cmd/5g: use MOVB for fixed array nil check
Fixes #4396.
For fixed arrays larger than the unmapped page, agenr would general a nil check by loading the first word of the array. However there is no requirement for the first element of a byte array to be word aligned, so this check causes a trap on ARMv5 hardware (ARMv6 since relaxed that restriction, but it probably still comes at a cost).
Switching the check to MOVB ensures alignment is not an issue. This check is only invoked in a few places in the code where large fixed arrays are embedded into structs, compress/lzw is the biggest offender, and switching to MOVB has no observable performance penalty.
Thanks to Rémy and Daniel Morsing for helping me debug this on IRC last night.
Ian Lance Taylor [Wed, 5 Dec 2012 00:51:51 +0000 (16:51 -0800)]
test: tweak bug273.go to not have constant len < cap when calling make
The current spec says that when calling make, if both len and
cap are constant, it is an error if len > cap. The gc
compiler does not yet implement that, but when it does this
will need to change. Changing it now for the benefit of
gccgo.
Robert Griesemer [Mon, 3 Dec 2012 22:23:41 +0000 (14:23 -0800)]
spec: channel operations are restricted by the channel direction
Also:
- 'for' statements with a range clause do not accept send-only
channels
- '_, _ = range ch' is not equivalent to "_ = range ch" if ch
is a channel (rewriting the latter to the former leads to
an invalid range clause).
These clarifications document the status quo.
R=rsc, r, iant, ken
CC=golang-dev
https://golang.org/cl/6874053
Dave Cheney [Mon, 3 Dec 2012 21:27:30 +0000 (08:27 +1100)]
cmd/dist: support building on debian/kFreeBSD
The debian/kFreeBSD project uses the FreeBSD kernel and the debian userspace. From our point of view, this is freebsd not linux as GOOS talks about the kernel syscall interface, not the userspace (although cgo alters that). As debian/kFreeBSD is experimental at this time, I do not think it is worth the effort of duplicating all the freebsd specific code so this is proposal represents a reasonable workaround.
Currently cgo is not supported, make.bash will detect this and disable cgo automatically during the build.
dfc@debian:~/go/src$ uname -a
GNU/kFreeBSD debian 8.1-1-686 #0 Sat Jul 21 17:02:04 UTC 2012 i686 i386 Intel(R) Core(TM) i5-2415M CPU @ 2.30GHz GNU/kFreeBSD
dfc@debian:~/go/src$ ../bin/go version
go version devel +d05272f402ec Sat Dec 01 15:15:14 2012 -0800
Johan Euphrosine [Sat, 1 Dec 2012 22:11:46 +0000 (14:11 -0800)]
math/rand: remove noop iteration in Perm
The first iteration always do `m[0], m[0] = m[0], m[0]`, because
`rand.Intn(1)` is 0.
fun note: IIRC in TAOCP version of this algorithm, `i` goes
backward (n-1->1), meaning that the "already" shuffled part of the
array is never altered betweens iterations, while in the current
implementation the "not-yet" shuffled part of the array is
conserved between iterations.
Dmitriy Vyukov [Fri, 30 Nov 2012 06:29:41 +0000 (10:29 +0400)]
runtime: better stack traces in race reports
When a race happens inside of runtime (chan, slice, etc),
currently reports contain only user file:line.
If the line contains a complex expression,
it's difficult to figure out where the race exactly.
This change adds one more top frame with exact
runtime function (e.g. runtime.chansend, runtime.mapaccess).
Dmitriy Vyukov [Fri, 30 Nov 2012 06:27:43 +0000 (10:27 +0400)]
cmd/gc: racewalk: collect stack traces in sync and sync/atomic
W/o this change stack traces do not show from where sync.Once()
or atomic.XXX was called.
This change add funcenter/exit instrumentation to sync/sync.atomic
packages.