TBR=dsymonds
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/112300043

This CL adds 'dropg', which is called to drop the association
between m and its current goroutine, and it makes schedule
handle locked goroutines correctly, instead of requiring all
callers of schedule to do that.

The effect is that if you want to take over an m for, say,
garbage collection work while still allowing the current g
to run on some other m, you can do an mcall to a function
that is:

        // dissociate gp
        dropg();
        gp->status = Gwaiting; // for ready

        // put gp on run queue for others to find
        runtime·ready(gp);

        /* ... do other work here ... */

        // done with m, let it run goroutines again
        schedule();

Before this CL, the dropg() body had to be written explicitly,
and the check for lockedg before schedule had to be
written explicitly too, both of which make the code a bit
more fragile than it needs to be.

LGTM=iant
R=dvyukov, iant
CC=golang-codereviews, rlh
https://golang.org/cl/113110043

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/112970044

CC=golang-codereviews
https://golang.org/cl/110640044

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

This variable allows users to select the compiler when using the
gccgo toolchain.

LGTM=rsc
R=rsc, iant, minux, aram
CC=axwalk, golang-codereviews
https://golang.org/cl/106700044

Fixes #7806.

LGTM=minux
R=golang-codereviews, minux
CC=golang-codereviews
https://golang.org/cl/104690043

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/116720043

warning: /usr/go/src/liblink/asm5.c:720 set and not used: m
warning: /usr/go/src/liblink/asm5.c:807 set and not used: c

LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/108570043

The debug/dwarf package cannot parse the format generated here,
but the format can be changed so it does.
After this edit, tweaking the expression defining the offset
of a struct field, the dwarf package can parse the tables (again?).

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/105710043

Fixes #6293.

Image "testdata/benchRGB-interlace.png" was generated by opening "testdata/benchRGB.png" in the editor Gimp and saving it with interlacing enabled.

Benchmark:
BenchmarkDecodeRGB        	     500	   7014194 ns/op	  37.37 MB/s
ok  	pkg/image/png	4.657s

BenchmarkDecodeInterlacing	     100	  10623241 ns/op	  24.68 MB/s
ok  	pkg/image/png	1.339s

LGTM=nigeltao
R=nigeltao, andybons, matrixik
CC=golang-codereviews
https://golang.org/cl/102130044

(This is a patch from the pkgsrc Go package.)

LGTM=iant
R=golang-codereviews, iant, joerg.sonnenberger, dave
CC=golang-codereviews, joerg
https://golang.org/cl/108340043

debug/elf: add (*File).DynamicSymbols, ErrNoSymbols, and tests for (*File).Symbols and (*File).DynamicSymbols, and formalize symbol order.

Added a complement to (*File).Symbols for the dynamic symbol table.
Would be useful, for instance, if seraching for certain shared objects
compatible with certain libraries (for instance, LADSPA requires an
exported symbol "ladspa_descriptor").

Added a variable ErrNoSymbols that canonicalizes a return from
(*File).Symbols and (*File).DyanmicSymbols if the file has no symbols.

Added tests for both (*File).Symbols and (*File).DynamicSymbols;
there was never a test for (*File).Symbols at all. A small C program using
libelf, included in the test data, was used to produce the golden
symbols to compare against.

As part of the requirements for testing, (*File).Symbols and (*File).DynamicSymbols now document the order in which the symbol tables are returned (in the order the symbols appear in the file).

All tests currently pass.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/107530043

The builder builds with GOROOT_FINAL=/usr/local/go set.

TBR=rsc
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/112100043

Also detect GOARCH automatically based on `uname -m`.

LGTM=crawshaw, dave, rsc
R=rsc, iant, crawshaw, dave
CC=golang-codereviews
https://golang.org/cl/111780043

LGTM=dave, rsc
R=rsc, iant, dave
CC=golang-codereviews
https://golang.org/cl/109390043

LGTM=dave, rsc
R=rsc, iant, dave
CC=golang-codereviews
https://golang.org/cl/101590044

It uses an unsupported addressing mode.

LGTM=iant, rsc
R=rsc, iant
CC=golang-codereviews
https://golang.org/cl/106370043

LGTM=dave, rsc
R=rsc, iant, dave
CC=golang-codereviews
https://golang.org/cl/101620043

LGTM=dave, rsc
R=rsc, iant, dave
CC=golang-codereviews
https://golang.org/cl/110330044

LGTM=rsc
R=rsc, iant, dave
CC=golang-codereviews
https://golang.org/cl/103680046

LGTM=dave, rsc
R=rsc, iant, dave
CC=golang-codereviews
https://golang.org/cl/108360043

LGTM=adg
R=adg
CC=dustmop, golang-codereviews
https://golang.org/cl/111000044

Fixes #8174.

LGTM=minux
R=golang-codereviews, minux
CC=golang-codereviews
https://golang.org/cl/102360043

Fixes #8224.

LGTM=alex.brainman, rsc
R=alex.brainman, rsc, dave
CC=golang-codereviews
https://golang.org/cl/104200046

Found using the vet check in CL 106370045.

This is a second attempt at CL 101670044, which omitted the deps_test change.

This adds dependencies to net/rpc:

        encoding
        encoding/base64
        encoding/json
        html
        unicode/utf16

The obvious correctness and security warrants the additional dependencies.

LGTM=rsc
R=r, minux, rsc, adg
CC=golang-codereviews
https://golang.org/cl/110890043

Generated by a+c.

R=gobot
CC=golang-codereviews
https://golang.org/cl/110970047

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/105100044

LGTM=iant
R=bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/112010045

LGTM=minux, bradfitz
R=golang-codereviews, minux, bradfitz
CC=golang-codereviews
https://golang.org/cl/104650043

LGTM=dave, iant
R=iant, dave
CC=golang-codereviews
https://golang.org/cl/112000043

When we've switched to 8K pages,
heap started to grow by 128K instead of 64K,
because it was implicitly assuming that pages are 4K.
Fix that and make the code more robust.

LGTM=khr
R=golang-codereviews, dave, khr
CC=golang-codereviews, rsc
https://golang.org/cl/106450044

LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/107640044

LGTM=0intro, dave
R=dave, 0intro
CC=golang-codereviews
https://golang.org/cl/106560044

Also remove arch-specific Go files in the Plan 9 syscall package

LGTM=0intro
R=0intro, dave
CC=ality, golang-codereviews, jas, mischief, rsc
https://golang.org/cl/112720043

LGTM=0intro
R=0intro
CC=ality, dave, golang-codereviews, jas, mischief, rsc
https://golang.org/cl/104570043

size instead of abusing text symbol

cmd/addr2line needs to know the virtual address of the start
of the text segment (load address plus header size). For
this, it used the text symbol added by the linker. This is
wrong on amd64. Header size is 40 bytes, not 32 like on 386
and arm. Function alignment is 16 bytes causing text to be
at 0x200030.

debug/plan9obj now exports both the load address and the
header size; cmd/addr2line uses this new information and
doesn't rely on text anymore.

LGTM=0intro
R=0intro, gobot, ality
CC=ality, golang-codereviews, jas, mischief
https://golang.org/cl/106460044

LGTM=0intro, r
R=0intro, r
CC=ality, golang-codereviews, jas, mischief
https://golang.org/cl/108420043

LGTM=0intro, r
R=0intro, r
CC=ality, dave, golang-codereviews, jas, mischief, rsc
https://golang.org/cl/111910043

LGTM=0intro, r
R=0intro, r
CC=ality, dave, golang-codereviews, jas, mischief, rsc
https://golang.org/cl/105580044