Start linker work

When the linker starts up, set link mode correctly and prepare to build
an ELF.

It crashes the linker if you try to link RISC-V code, but the linker
recognizes the riscv GOARCH, and there are a bunch of function stubs
just waiting to be implemented.

cmd/internal/obj: run go fmt

Change-Id: I45d82efe05c08ac59da7784c2a2c13949da912b4

Start asm work

As a first step in progedit, mark branching instructions as branches, as
other arches do.

Change-Id: Ia8e8dbb52ace860d3e461d76b5e7ef9ecbbdff6c

We are just getting and idea of what we are being passed.

Change-Id: I95966efcbc055f704e04d0d818a215e4a856e62a

Its range actually extends beyond 13k, so extend it all the way up to
16k.

Change-Id: Iad3281695d2e84b8895637ed274e447b36358f76

This adds a no-op LinkArch that is actually tied in to a real RISCV asm
obj package, with instruction definitions. Now the hard work begins...

$ cd $(GO)/src
$ GOROOT=$(pwd)/.. GOROOT_BOOTSTRAP=/bootstrap/tools/path ./make.bash
$ cd $(GO)
$ GOARCH=riscv ./pkg/tool/linux_amd64/asm -debug test.s

Change-Id: I16714c560651c8c22791d09f779c5e04c2cc4e40

It can't actually assemble anything, but the tool recognizes it.

Change-Id: Ic325923dfe81f1fb53678019f1f4f69e9a18ae04

Convert some fields of struct Type in go.go from uint8 to bool.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I0a6c53f8ee686839b5234010ee2de7ae3940d499
Reviewed-on: https://go-review.googlesource.com/14370


Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Convert Pkg.Imported, Pkg.Exported, Pkg.Direct from uint8/int8/int8 to bool.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I67a71f1186ff9737c03eca413f7d35d8a79ebc9b
Reviewed-on: https://go-review.googlesource.com/14371


Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Passes go build -a -toolexec 'toolstash -cmp' std cmd.

Change-Id: I804ee4252fa9be78cb277faf7f467e6c9cfdd4a6
Reviewed-on: https://go-review.googlesource.com/14319


Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Remove unused field Type.Siggen in go.go.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: Ia61fe65a226c913fbf4a11a71d7453c56aa46c0e
Reviewed-on: https://go-review.googlesource.com/14372


Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

Passes go build -a -toolexec 'toolstash -cmp' std.

Change-Id: Ica62765d3c1ef052afed34da1b3ac3f80646cc55
Reviewed-on: https://go-review.googlesource.com/14318


Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Convert Type.Broke from a uint8 to a boolean

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I44e7548c71b00467e36576bdf62933c42555a21a
Reviewed-on: https://go-review.googlesource.com/14307


Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Håvard Haugen <havard.haugen@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Convert Label.Used to a boolean. Also move the field to the
bottom of the struct to avoid padding.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: If09ee92f9d54dce807e7b862cf771005daed810d
Reviewed-on: https://go-review.googlesource.com/14308


Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Change-Id: Iccb0221bd9aef062d20798b952eaa09d9e60b902
Reviewed-on: https://go-review.googlesource.com/14345


Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Nicer swaps, loops (removed tmp variables). Use of bool instead of int.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I541904c74b57297848decc51a8a4913a8eca4af3
Reviewed-on: https://go-review.googlesource.com/14316


Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

When building a shared library, all functions that are declared must actually
be defined.

Change-Id: I1488690cecfb66e62d9fdb3b8d257a4dc31d202a
Reviewed-on: https://go-review.googlesource.com/14187


Reviewed-by: Dave Cheney <dave@cheney.net>

Fix mkzversion to produce correctly formatted runtime/zversion.go.

Change-Id: Ie6bcd361a2f2e390b7f6c4980fcae2c41bb7e52f
Reviewed-on: https://go-review.googlesource.com/14355


Reviewed-by: Andrew Gerrand <adg@golang.org>

This one of a set of changes to make the transition away from NodeList
easier by removing cases in which NodeList doesn't act semi-trivially like a
[]*Node.

This CL was originally prepared by Josh Bleecher Snyder <josharian@gmail.com>.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I4d041b343952f4a31f3150fd70669e08fcaa74f8
Reviewed-on: https://go-review.googlesource.com/14305


Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The code parsing register lists involves an inner loop on
each range defined by the lo,hi bounds. The condition on
this loop (for lo<=hi) is fragile, because the bounds
are unsigned 16 bits numbers.

In some corner cases, the calculated upper bound is 2^16-1
leading to an infinite loop.

Parsing operand `[):[o-FP` results in:
- an infinite loop for non ARM architectures
- the generation of almost 2^16 errors for the ARM architecture
  (which are then ignored)

This CL improves the code in 3 ways:
- bail out early when parsing non R prefixed registers
- make sure the register index is never negative
- make sure the number of iterations is limited by the
  maximum size of the range (as a defensive measure).

Fixes #12469

Change-Id: Ib1e7e36fb8ad5a3a52c50fc6219d3cfe2b39cc34
Reviewed-on: https://go-review.googlesource.com/14314


Reviewed-by: Rob Pike <r@golang.org>

This one of a set of changes to make the transition away from NodeList
easier by removing cases in which NodeList doesn't act semi-trivially like a
[]*Node.

This CL was originally prepared by Josh Bleecher Snyder <josharian@gmail.com>.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: I582ff8b077eb384b84721a1edb0c1efbc0c40059
Reviewed-on: https://go-review.googlesource.com/14304


Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>

When running an experimental kernel with IPv4 disabled, Listen(":port")
currently tries to create an AF_INET socket, and fails.  Instead, it
should see !supportsIPv4, and use an AF_INET6 socket.

This sort of environment is quite esoteric at the moment, but I can
force the tests to fail on regular Linux using the following tweaks:

- net/net.go: supportsIPv4, supportsIPv6, supportsIPv4map = false, true, false
- net/sockopt_linux.go: ipv6only=true
- net/ipsock_posix.go: Revert this fix
- ./make.bash && ../bin/go test net

Also, make the arrows in server_test.go point to the left, because
server<-client is easier to read.

Fixes #12510

Change-Id: I0cc3b6b08d5e6908d2fbf8594f652ba19815aa4b
Reviewed-on: https://go-review.googlesource.com/14334


Run-TryBot: Paul Marks <pmarks@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

This is a first of a set of changes to make the transition away from NodeList
easier by removing cases in which NodeList doesn't act semi-trivially like a
[]*Node.

This CL was originally prepared by Josh Bleecher Snyder <josharian@gmail.com>.

This change passes go build -toolexec 'toolstash -cmp' -a std.

Change-Id: Iad10b75e42b5b24e1694407841282fa3bab2dc9f
Reviewed-on: https://go-review.googlesource.com/14232


TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This is more correct with respect to garbage collection.
I don't know of any specific failures it could cause today.

Change-Id: I7eed6a06d2f281051199e79e4a9913aa8360ded7
Reviewed-on: https://go-review.googlesource.com/14137


Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Also go generate to update generated files.

Change-Id: I049708db93455f0030ba5afc6f218fde6220958d
Reviewed-on: https://go-review.googlesource.com/14331


Reviewed-by: Damien Neil <dneil@google.com>

TestNoteReading fails on Solaris with linkmode=external due to some
assumptions made about how ELF .note sections are written by some
linkers.

On current versions of Solaris and older derivatives, SHF_ALLOC is
intentionally ignored for .note sections unless the .note section is
assigned to the text segment via a mapfile.  Also, if .note sections
are assigned to the text segment, no PT_NOTE program header will be
created thwarting Go's attempts at attempting to quickly find the
.note.

Furthermore, Go assumes that the relevant note segment will be placed
early in the file while the Solaris linker currently places the note
segment last in the file, additionally thwarting Go's optimisation
attempts that read only the first 16KB of the file to find the
buildid.

The fix is to detect when the note section is outside of the first
16KB of the file and then fallback to additionally reading that
section of the file.  This way, in future versions of Solaris when
this linking behaviour is changed, the fast path will always succeed
and we'll only be slower if it fails; likewise, any other linker that
does this will also just work.

Fixes #12178

Change-Id: I61c1dc3f744ae3ad63938386d2ace8a432c0efe1
Reviewed-on: https://go-review.googlesource.com/14210


Run-TryBot: Aram Hăvărneanu <aram@mgk.ro>
Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>

Revert "cmd/internal/ld: put read-only relocated data into .data.rel.ro when making a shared object"

This reverts commit 2c2cbb69.

Broke darwin/arm64

Change-Id: Ibd2dea475d6ce6a8b4b40e2da19a83fc0514025d
Reviewed-on: https://go-review.googlesource.com/14301


Reviewed-by: Ian Lance Taylor <iant@golang.org>

Fixes #8434

Change-Id: I323222b4160f3aba35cac1de7f6df93c524b72ec
Reviewed-on: https://go-review.googlesource.com/14169


Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Optimize two calls of io.Copy which cannot make use of neither
io.ReaderFrom nor io.WriterTo optimization tricks by replacing them with
io.CopyBuffer with reusable buffers.

First is fallback call to io.Copy when server misses the optimized case
of using sendfile to copy from a regular file to net.TCPConn; second is
use of io.Copy on piped reader/writer when handler implementation uses
http.CloseNotifier interface. One of the notable users of
http.CloseNotifier is httputil.ReverseProxy.

benchmark                    old ns/op     new ns/op     delta
BenchmarkCloseNotifier-4     309591        303388        -2.00%

benchmark                    old allocs     new allocs     delta
BenchmarkCloseNotifier-4     50             49             -2.00%

benchmark                    old bytes     new bytes     delta
BenchmarkCloseNotifier-4     36168         3140          -91.32%

Fixes #12455

Change-Id: I512e6aa2f1aeed2ed00246afb3350c819b65b87e
Reviewed-on: https://go-review.googlesource.com/14177


Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #11000

Change-Id: Ic137e8a6c5c6b5b7eee213aca9acf78368e1d686
Reviewed-on: https://go-review.googlesource.com/14296


Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Simplify slice/map literal expressions.
Caught with gofmt -d -s, fixed with gofmt -w -s
Checked that the result can still be compiled with Go 1.4.

Change-Id: I5c58801c20919618d2ad52b8e2380d53df2783f1
Reviewed-on: https://go-review.googlesource.com/13831


Reviewed-by: Andrew Gerrand <adg@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Simplify slice/map literal expressions.
Caught with gofmt -d -s, fixed with gofmt -w -s

Change-Id: Iefd5f263c4f89a81da9427a7b9d97f13c35ab64f
Reviewed-on: https://go-review.googlesource.com/13838


Reviewed-by: Andrew Gerrand <adg@golang.org>

All the code was there to do this, it just wasn't hooked up.

Fixes #10914

Change-Id: Ide8f9bbe50fecb5d11cd579915ee98d4c7efe403
Reviewed-on: https://go-review.googlesource.com/14142


Reviewed-by: Ian Lance Taylor <iant@golang.org>

This is generated during fp code when -shared is active.

Change-Id: Ia1092299b9c3b63ff771ca4842158b42c34bd008
Reviewed-on: https://go-review.googlesource.com/14286


Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>

Some symbols, for example, masks requires 16-byte alignment, and
they are placed in the text section. Before this change, the text
section is only aligned to 4-byte, and it's making masks unaligned.

Fixes #12415.

Change-Id: I7767778d1b4f7d3e74c2719a02848350782a4160
Reviewed-on: https://go-review.googlesource.com/14166


Run-TryBot: Minux Ma <minux@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>