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
This is a quick documentation change/clarification, as this
confused me before: in my own cgo-based projects, I currently have
identical #cgo directives in each relevant source file, and I notice
with go build -x that cgo is combining the directives, leading to
pkg-config invocations with the same package name (gtk+-3.0, in my
case) repeated several times, or on Mac OS X, LDFLAGS listing
-framework Foundation -framework AppKit multiple times. Since I am
about to add a CFLAGS as well, I checked the source to cmd/cgo and
go/build (where the work is actually done) to see if that still holds
true there. Hopefully other people who have made the same mistake I
have (I don't know if anyone has) can remove the excess declarations
now; this should make things slightly easier to manage as well.
LGTM=iant
R=golang-codereviews, gobot, iant
CC=golang-codereviews
https://golang.org/cl/91520046
Ignore symbols that aren't text, data, or bss since they cause
problems when dissassembling instructions with small immediate
values.
Before:
build.go:142 0x10ee 83ec50 SUBL $text/template/parse.autotmp_1293(SB), SP
After:
build.go:142 0x10ee 83ec50 SUBL $0x50, SP
Fixes#7947.
LGTM=rsc
R=rsc, 0intro
CC=golang-codereviews
https://golang.org/cl/93520045
Passes the expanded test in CL 100660044,
which gives me some confidence that it
might be right.
(The old code failed by not considering all the
low bits.)
LGTM=r
R=golang-codereviews, r, bradfitz
CC=golang-codereviews, iant, khr
https://golang.org/cl/99410051
Rewrite formatFloat to be much simpler and clearer and
avoid the tricky interaction with padding.
The issue refers to complex but the problem is just floating-point.
The new tests added were incorrectly formatted before this fix.
Fixes#8064.
LGTM=jscrockett01, rsc
R=rsc, jscrockett01
CC=golang-codereviews
https://golang.org/cl/99420048
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
This idea was rejected in CL 5731059. We should fix the
runtime docs instead.
««« original CL description
cmd/dist: reflect local changes to tree in goversion
runtime.Version() requires a trailing "+" when
tree had local modifications at time of build.
Fixes#7701
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/84040045
»»»
LGTM=rsc, mra
R=iant, rsc, mra
CC=golang-codereviews
https://golang.org/cl/100520043
Explain which files the go command looks at, and what they represent.
Fixes#6348.
LGTM=rsc
R=rsc, minux.ma
CC=golang-codereviews
https://golang.org/cl/96480043
Add nacl.bash, the NaCl version of all.bash.
It's a separate script because it builds a variant of package syscall
with a large zip file embedded in it, containing all the input files
needed for tests.
Disable various tests new since the last round, mostly the ones using os/exec.
Fixes#7945.
LGTM=dave
R=golang-codereviews, remyoudompheng, dave, bradfitz
CC=golang-codereviews
https://golang.org/cl/100590044
I don't know when the bug was fixed, but empirically it was.
Make sure it stays fixed by adding a test.
Fixes#7884.
LGTM=adg
R=golang-codereviews, adg
CC=golang-codereviews
https://golang.org/cl/93500043
The USEFIELD instructions no longer make it to the linker,
so we have to do something else to pin the references
they were pinning. Emit a 0-length relocation of type R_USEFIELD.
Fixes#7486.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/95530043
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
The float32 const conversion used to round to float64
and then use the hardware to round to float32.
Even though there was a range check before this
conversion, the double rounding introduced inaccuracy:
the round to float64 might round the value further away
from the float32 range, reaching a float64 value that
could not actually be rounded to float32. The hardware
appears to give us 0 in that case, but it is probably undefined.
Double rounding also meant that the wrong value might
be used for certain border cases.
Do the rounding the float32 ourselves, just as we already
did the rounding to float64. This makes the conversion
precise and also makes the conversion match the range check.
Finally, add some code to print very large (bigger than float64)
floating point constants in decimal floating point notation instead
of falling back to the precise but human-unreadable binary floating
point notation.
Fixes#8015.
LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews, r
https://golang.org/cl/100580044
Update #7980
This CL make the linker abort for the example program. For Go 1.4,
we need to find a general way to handle large memory model programs.
LGTM=dave, josharian, iant
R=iant, dave, josharian
CC=golang-codereviews
https://golang.org/cl/91500046
The temporary-introducing pass was not recursing
into the argumnt of a receive operation.
Fixes#8011.
LGTM=r
R=golang-codereviews, r
CC=golang-codereviews, iant, khr
https://golang.org/cl/91540043
This is the main point of confusion and the emphasis of
a recent Gophercon talk.
Fixes#5886. (mostly fixed in previous commits)
LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/100560043
