Some systems, like Ubuntu, pass --build-id when linking.  The
effect is to put a note in the output file.  This is not
useful when generating an object file with the -r option, as
it eventually causes multiple build ID notes in the final
executable, all but one of which are for tiny portions of the
file and are therefore useless.

Disable that by passing an explicit --build-id=none when
linking with -r on systems that might do this.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/119460043

LGTM=dvyukov
R=dvyukov, khr
CC=golang-codereviews
https://golang.org/cl/121030043

There are lots of internal synchronization in gob,
so it makes sense to have parallel benchmarks.
Also add a benchmark with slices and interfaces.

LGTM=r
R=golang-codereviews, r
CC=golang-codereviews
https://golang.org/cl/115960043

This lets us have non-main packages like cmd/internal or cmd/nm/internal/whatever.

The src/pkg migration (see golang.org/s/go14mainrepo) will allow this
as a natural side effect. The explicit change here just allows use of the
effect a little sooner.

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/117630043

To do in another CL: make cmd/objdump use cmd/internal/objfile too.

There is a package placement decision in this CL:
cmd/internal/objfile instead of internal/objfile.
I chose to put internal under cmd to make clear (and enforce)
that no standard library packages should use this
(it's a bit dependency-heavy).

LGTM=r
R=r
CC=golang-codereviews
https://golang.org/cl/123910043

Update #8314

TBR=r
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/123890043

Eliminating use of this extension makes it easier to port the Go runtime
to other compilers. This CL also disables the extension in cc to prevent
accidental use.

LGTM=rsc, khr
R=rsc, aram, khr, dvyukov
CC=axwalk, golang-codereviews
https://golang.org/cl/106790044

This makes os.Getwd mimic C getwd on OS X,
and possibly other systems. The change on OS X
was a regression from 1.2 to 1.3.

Fixes #8400.

LGTM=bradfitz
R=iant, bradfitz
CC=golang-codereviews
https://golang.org/cl/118970043

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/123880043

benchmark                      old ns/op     new ns/op     delta
BenchmarkMalloc8               28.7          22.4          -21.95%
BenchmarkMalloc16              44.8          33.8          -24.55%
BenchmarkMallocTypeInfo8       49.0          32.9          -32.86%
BenchmarkMallocTypeInfo16      46.7          35.8          -23.34%
BenchmarkMallocLargeStruct     907           901           -0.66%
BenchmarkGobDecode             13235542      12036851      -9.06%
BenchmarkGobEncode             10639699      9539155       -10.34%
BenchmarkJSONEncode            25193036      21898922      -13.08%
BenchmarkJSONDecode            96104044      89464904      -6.91%

Fixes #8452.

LGTM=khr
R=golang-codereviews, bradfitz, rsc, dave, khr
CC=golang-codereviews
https://golang.org/cl/122090043

Fix few remaining cases after cl/117580043.

TBR=dfc
R=golang-codereviews
CC=dave, golang-codereviews
https://golang.org/cl/124850043

FlagNoGC is unused now.
FlagNoInvokeGC is unneeded as we don't invoke GC
on g0 and when holding locks anyway.
mal/malloc have very few uses and you never remember
the exact set of flags they use and the difference between them.
Moreover, eventually we need to give exact types to all allocations,
something what mal/malloc do not support.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, rsc
https://golang.org/cl/117580043

Shrinkstack does not touch normal heap anymore,
so we can shink stacks concurrently with marking.

LGTM=khr
R=golang-codereviews, khr
CC=golang-codereviews, khr, rlh, rsc
https://golang.org/cl/122130043

Fixes #8403.

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/123860043

LGTM=dan.kortschak, dave
R=dave, dan.kortschak
CC=golang-codereviews
https://golang.org/cl/121350043

TBR=gobot
R=golang-codereviews
CC=golang-codereviews
https://golang.org/cl/125790043

LGTM=minux
R=r, agl, minux
CC=golang-codereviews
https://golang.org/cl/121340043

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/126760043

LGTM=dave
R=golang-codereviews, dave
CC=golang-codereviews
https://golang.org/cl/122910043

Among other things, this allows users to match the decoded
pieces with the original XML, which can be necessary for
implementing standards like XML signatures.

Fixes #8484.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/122960043

This fixes two problems: x/internal/y/z was using parent = x/internal/y instead of x,
and hasPathPrefix only looks at /, not \ for Windows.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/121280045

LGTM=iant, bradfitz
R=bradfitz, iant
CC=golang-codereviews
https://golang.org/cl/120700043

Introduce the mFunction type to represent an mcall/onM-able function.
Name such functions using _m.

LGTM=bradfitz
R=bradfitz
CC=golang-codereviews
https://golang.org/cl/121320043

LGTM=rsc, khr
R=rsc, khr, bradfitz
CC=golang-codereviews
https://golang.org/cl/126720043

Hashing on the bytes instead of the words does
a (much) better job of using all the bits, so that
maps of floats have linear performance.

LGTM=khr
R=golang-codereviews, khr
CC=adonovan, golang-codereviews
https://golang.org/cl/126720044

See golang.org/s/go14internal for design.

LGTM=r
R=r, adg
CC=golang-codereviews
https://golang.org/cl/120600043

LGTM=iant
R=dvyukov, iant
CC=golang-codereviews
https://golang.org/cl/117680044

The implementation 'return 0' results in too many collisions.

LGTM=khr
R=golang-codereviews, adonovan, khr
CC=golang-codereviews, iant, khr, r
https://golang.org/cl/125720044

Causes server 500 error, so don't do it.

TBR=minux
CC=golang-codereviews
https://golang.org/cl/125770043

hg insists that we not list explicit files for a merge.

for benefit of other tools reading logs, include branch prefix
at start of every commit message.

LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/124780044

1) The arrayindexof lookup function is O(n). Replace with O(1) lookups.

2) The checkptxt function is O(n²) and is purely for debugging.
Only run when the debugging flags are turned on.

3) Iterating over sparse bitmaps can be done faster word by word.
Introduce and use bvnext for that.

Run times before and after, on my 2.5 GHz Core i5 MacBook Pro.

x.go       9.48  0.84  issue 8259

x100.go    0.01  0.01  issue 8354
x1000.go   0.10  0.10
x2000.go   0.62  0.19
x3000.go   1.33  0.34
x4000.go   2.29  0.49
x5000.go   3.89  0.67
x6000.go   5.00  0.90
x7000.go   6.70  1.13
x8000.go   9.44  1.38
x9000.go  11.23  1.87
x10000.go 13.78  2.09

Fixes #8259.
Fixes #8354.

LGTM=iant, r
R=golang-codereviews, iant, r
CC=golang-codereviews
https://golang.org/cl/125720043

LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/118690043

LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/124800043

The linker currently produces the DWARF 3 DW_TAG_unspecified_type tag, however the Reader in debug/dwarf will panic whenever that tag is encountered.

Fixes #8437.

LGTM=rsc
R=golang-codereviews, bradfitz, iant, rsc
CC=golang-codereviews
https://golang.org/cl/117280043

Generated by a+c.

R=gobot
CC=golang-codereviews
https://golang.org/cl/125750043

This is an experiment. See mail on golang-dev
(subject: "an experiment: development branches").

LGTM=minux
R=minux
CC=golang-codereviews
https://golang.org/cl/117660043

It can happen legitimately if a profiling signal arrives at just the wrong moment.
It's harmless.

Fixes #8153.

LGTM=minux
R=golang-codereviews, minux
CC=golang-codereviews, iant, r
https://golang.org/cl/118670043

Revised version of https://golang.org/cl/81260045/

LGTM=agl
R=golang-codereviews, gobot, agl, ox
CC=golang-codereviews
https://golang.org/cl/107400043

Fixes #8478.

LGTM=iant
R=iant
CC=golang-codereviews
https://golang.org/cl/122150043

Left over from cl/119490044.

LGTM=bradfitz
R=rsc, bradfitz
CC=golang-codereviews
https://golang.org/cl/125730043