This change introduces NaNs (for situations like Inf-Inf, etc.).
The implementation is incomplete (the four basic operations produce
a NaN if any of the operands is an Inf or a NaN); and some operations
produce incorrect accuracy for NaN arguments. These are known bugs
which are documented.

Change-Id: Ia88841209e47930681cef19f113e178f92ceeb33
Reviewed-on: https://go-review.googlesource.com/6540Reviewed-by: Alan Donovan <adonovan@google.com>

These benchmarks show the effect of the combination of this change
and Rick's pending CL 6665. Code with interior pointers is helped
much more than code without, but even code without doesn't suffer
too badly.

benchmark                          old ns/op      new ns/op      delta
BenchmarkBinaryTree17              6989407768     6851728175     -1.97%
BenchmarkFannkuch11                4416250775     4405762558     -0.24%
BenchmarkFmtFprintfEmpty           134            130            -2.99%
BenchmarkFmtFprintfString          491            402            -18.13%
BenchmarkFmtFprintfInt             430            420            -2.33%
BenchmarkFmtFprintfIntInt          748            663            -11.36%
BenchmarkFmtFprintfPrefixedInt     602            534            -11.30%
BenchmarkFmtFprintfFloat           728            699            -3.98%
BenchmarkFmtManyArgs               2528           2507           -0.83%
BenchmarkGobDecode                 17448191       17749756       +1.73%
BenchmarkGobEncode                 14579824       14370183       -1.44%
BenchmarkGzip                      656489990      652669348      -0.58%
BenchmarkGunzip                    141254147      141099278      -0.11%
BenchmarkHTTPClientServer          94111          93738          -0.40%
BenchmarkJSONEncode                36305013       36696440       +1.08%
BenchmarkJSONDecode                124652000      128176454      +2.83%
BenchmarkMandelbrot200             6009333        5997093        -0.20%
BenchmarkGoParse                   7651583        7623494        -0.37%
BenchmarkRegexpMatchEasy0_32       213            213            +0.00%
BenchmarkRegexpMatchEasy0_1K       511            494            -3.33%
BenchmarkRegexpMatchEasy1_32       186            187            +0.54%
BenchmarkRegexpMatchEasy1_1K       1834           1827           -0.38%
BenchmarkRegexpMatchMedium_32      427            412            -3.51%
BenchmarkRegexpMatchMedium_1K      154841         153086         -1.13%
BenchmarkRegexpMatchHard_32        7473           7478           +0.07%
BenchmarkRegexpMatchHard_1K        233587         232272         -0.56%
BenchmarkRevcomp                   918797689      944528032      +2.80%
BenchmarkTemplate                  167665081      167773121      +0.06%
BenchmarkTimeParse                 631            636            +0.79%
BenchmarkTimeFormat                672            666            -0.89%

Change-Id: Ia923de3cdb3993b640fe0a02cbe2c7babc16f32c
Reviewed-on: https://go-review.googlesource.com/6782Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Austin Clements <austin@google.com>

Gc already calculates n as an int, so converting to int64 to call
growslice doesn't serve any purpose except to emit slightly larger
code on 32-bit platforms.  Passing n as an int shrinks godoc's text
segment by 8kB (9472633 => 9464133) when building for ARM.

Change-Id: Ief9492c21d01afcb624d3f2a484df741450b788d
Reviewed-on: https://go-review.googlesource.com/6231Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

SHRQ CX, DX:AX is changing to SHRQ CX, AX, DX.
This is the first step: using SHRQ From=CX, From3=AX, To=DX
as the preferred encoding.
Once the assemblers and 6g have been updated,
support for the old encoding can be removed.

Change-Id: Ie603fb8ac25a6df78e42f7ddcae078a7684a7c26
Reviewed-on: https://go-review.googlesource.com/6693Reviewed-by: Rob Pike <r@golang.org>

The unbounded list-based defer pool can grow infinitely.
This can happen if a goroutine routinely allocates a defer;
then blocks on one P; and then unblocked, scheduled and
frees the defer on another P.
The scenario was reported on golang-nuts list.

We've been here several times. Any unbounded local caches
are bad and grow to infinite size. This change introduces
central defer pool; local pools become fixed-size
with the only purpose of amortizing accesses to the
central pool.

Freedefer now executes on system stack to not consume
nosplit stack space.

Change-Id: I1a27695838409259d1586a0adfa9f92bccf7ceba
Reviewed-on: https://go-review.googlesource.com/3967Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>

The unbounded list-based sudog cache can grow infinitely.
This can happen if a goroutine is routinely blocked on one P
and then unblocked and scheduled on another P.
The scenario was reported on golang-nuts list.

We've been here several times. Any unbounded local caches
are bad and grow to infinite size. This change introduces
central sudog cache; local caches become fixed-size
with the only purpose of amortizing accesses to the
central cache.

The change required to move sudog cache from mcache to P,
because mcache is not scanned by GC.

Change-Id: I3bb7b14710354c026dcba28b3d3c8936a8db4e90
Reviewed-on: https://go-review.googlesource.com/3742Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>

The original C code is: (x->type & SHIDDEN) ? 2 : 0, however when
cleaning up the code for c2go, the ternary operator is rewritten in
the exact opposite way.

We need a test for this, and that's being tracked as #10070.

Fixes #10067.

Change-Id: I24a5e021597d8bc44218c6e75bab6446513b76cf
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/6730Reviewed-by: Ian Lance Taylor <iant@golang.org>

The creation of liblink and subsequent introduction of more explicit
TLS handling broke 6l's (unsupported) -shared flag.  This change adds
-shared flags to cmd/asm and 6g and changes liblink to generate shared-
library compatible instruction sequences when they are passed, and
changes 6l to emit the appropriate ELF relocation.

A proper fix probably also requires go tool changes.

Fixes #9652.

Change-Id: I7b7718fe7305c802ac994f4a5c8de68cfbe6c76b
Reviewed-on: https://go-review.googlesource.com/4321Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes the linux-amd64-nocgo builder.

Regression from https://golang.org/cl/6531

Change-Id: Ibffd1ecfee4a888605ed54196f53956ae42e591c
Reviewed-on: https://go-review.googlesource.com/6700Reviewed-by: Andrew Gerrand <adg@golang.org>

Change-Id: I01e328fc3644b679bacf2209c3d7ade9d8bffe53
Reviewed-on: https://go-review.googlesource.com/6551Reviewed-by: Rob Pike <r@golang.org>

cmd/asm/internal/asm no longer imports obj/$GOARCH, only obj itself.

Change-Id: I7c0d107524d833b4a1b6e6a497cca4addadee570
Reviewed-on: https://go-review.googlesource.com/6670Reviewed-by: Russ Cox <rsc@golang.org>

The name g is an alias for R10 and R30, respectively. Have Rconv
print the alias, for consistency with the input language.

Change-Id: Ic3f40037884a0c8de5089d8c8a8efbcdc38c0d56
Reviewed-on: https://go-review.googlesource.com/6630Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

This will enable test sharding over multiple VMs, to speed trybot answers.

Update #10029

Change-Id: Ie277c6459bc38005e4d6af14d22effeaa0a4667e
Reviewed-on: https://go-review.googlesource.com/6531Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>

Issue #10043

Change-Id: I6ce7f303cd96ac575f7a673dd4a459339382d22e
Reviewed-on: https://go-review.googlesource.com/6692Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

We now wait until we see the completed prompt from a command before
proceeding. This seems to cut down on a spurious error I have seen
this afternoon.

Change-Id: Ic0a3481d8c265c3c3b4449ec7ac1c2752b85b0b6
Reviewed-on: https://go-review.googlesource.com/6691Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Just a missed case in in the handling of branches.

Fixes #10065

Change-Id: I6be054d30bf1f383c12b4c7626abd5f8ae22b22e
Reviewed-on: https://go-review.googlesource.com/6631Reviewed-by: Minux Ma <minux@golang.org>

Apply mask fix from 527b478e to ppc64.

Change-Id: Iac62228f0f04fa8b138e21d82786026158267aaf
Reviewed-on: https://go-review.googlesource.com/6582Reviewed-by: Rob Pike <r@golang.org>

c2go produced accurate but complex constant definitions like
"ElfSymBindLocal  = 0 + iota - 67" which break when any constants
are added above them in the list. Change them to explicit values
in separate blocks by class. I wrote a little program (using awk)
to dump the values of the constants:

    https://gist.github.com/mwhudson/82f82008279a38ce584e

and confirmed that its output before and after this change is the
same.

Change-Id: Ib4aea4a0d688a16cdcb76af4715d1a97ec0f013c
Reviewed-on: https://go-review.googlesource.com/6581
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

- use Bvec, not *Bvec, and bulk allocate backing store
- use range loops
- put Bvecs in BasicBlock struct instead of indexing into parallel slices

Change-Id: I5cb30f50dccb4d38cc18fae422f7f132c52876be
Reviewed-on: https://go-review.googlesource.com/6602Reviewed-by: Rob Pike <r@golang.org>

Also change gc.Naddr to return the Addr instead of filling it in.

Change-Id: I98a86705d23bee49626a12a042a4d51cabe290ea
Reviewed-on: https://go-review.googlesource.com/6601Reviewed-by: Rob Pike <r@golang.org>

The C version of the compiler had just one hash table,
indexed by a (name string, pkg *Pkg) pair.
Because we always know the pkg during a lookup,
replace the one table with a per-Pkg map[string]*Sym.
This also lets us do non-allocating []byte key lookups.

This CL *does* change the generated object files.
In the old code, export data and init calls were emitted
in "hash table order". Now they are emitted in the order
in which they were added to the table.

Change-Id: I5a48d5c9add996dc43ad04a905641d901522de0b
Reviewed-on: https://go-review.googlesource.com/6600Reviewed-by: Rob Pike <r@golang.org>

Strlit was just a poor excuse for a Go string.
Use a Go string.
In the one case where it was a string-or-nil (Type.Note), use a *string.

Zconv was a poor excuse for %q. Use %q.
The only important part about Zconv's implementation
was that the compiler and linker agreed on the quoting rules.
Now they both use %q instead of having two Zconvs.

This CL *does* change the generated object files, because the
quoted strings end up in symbol names.
For example the string "\r\n" used to be named go.string."\r\n"
and is now go.string."\x0d\n".

Change-Id: I5c0d38e1570ffc495f0db1a20273c9564104a7e8
Reviewed-on: https://go-review.googlesource.com/6519Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Rob Pike <r@golang.org>

This avoids the argument appearing to escape
(due to the fact that proginfo is always called
via a function pointer).

Change-Id: Ib9351ba18c80fd89e6a1d4f19dea386d4c657337
Reviewed-on: https://go-review.googlesource.com/6518Reviewed-by: Rob Pike <r@golang.org>

Run rsc.io/grind rev 796d0f2 on C->Go conversions.

This replaces various awkward := initializations with plain var declarations.

Checked bit-for-bit compatibility with toolstash + buildall.

Change-Id: I601101d8177894adb9b0e3fb55dfe0ed4f544716
Reviewed-on: https://go-review.googlesource.com/6517Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

On one recent job I saw an unexpected SIGSTOP, which I suspect is
simply the job timeout. But the lack of other diagnostics suggests
lldb just didn't see the "run" command.

-----

process handle SIGHUP  --stop false --pass true --notify false
process handle SIGPIPE --stop false --pass true --notify false
process handle SIGUSR1 --stop false --pass true --notify false
process handle SIGSEGV --stop false --pass true --notify false
process handle SIGBUS  --stop false --pass true --notify false
breakpoint set -n getwd
run
(lldb) NAME        PASS   STOP   NOTIFY
==========  =====  =====  ======
SIGHUP      true   false  false
(lldb) NAME        PASS   STOP   NOTIFY
==========  =====  =====  ======
SIGPIPE     true   false  false
(lldb) NAME        PASS   STOP   NOTIFY
==========  =====  =====  ======
SIGUSR1     true   false  false
(lldb) NAME        PASS   STOP   NOTIFY
==========  =====  =====  ======
SIGSEGV     true   false  false
(lldb) NAME        PASS   STOP   NOTIFY
==========  =====  =====  ======
SIGBUS      true   false  false
(lldb) Breakpoint 1: where = libsystem_c.dylib`getwd, address = 0x2f7f7294
(lldb) Process 23755 stopped
* thread #1: tid = 0x104c02, 0x1febb000 dyld`_dyld_start, stop reason = signal SIGSTOP
    frame #0: 0x1febb000 dyld`_dyld_start
dyld`_dyld_start:
-> 0x1febb000:  mov    r8, sp
   0x1febb004:  sub    sp, sp, #0x10
   0x1febb008:  bic    sp, sp, #0x7
   0x1febb00c:  ldr    r3, [pc, #112]            ; _dyld_start + 132
(lldb) go_darwin_arm_exec: timeout (stage br getwd)
FAIL	compress/gzip	359.226s

Change-Id: Ifc2123f5ceaa6d3f9b31bb5cb6e77a2c8ec23818
Reviewed-on: https://go-review.googlesource.com/6613Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Change-Id: If2d303caae933eec61634152e5d83faaba591315
Reviewed-on: https://go-review.googlesource.com/6660Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Mishandled the mask for the arm instructions.

TBR=rsc

Change-Id: Idc596097c0fa61dcacdfb4aca5bc6d0b4fd40eeb
Reviewed-on: https://go-review.googlesource.com/6641Reviewed-by: Rob Pike <r@golang.org>

Change-Id: I38d716de9d5a9c1b868641262067d0456d52c86d
Reviewed-on: https://go-review.googlesource.com/6612Reviewed-by: Ian Lance Taylor <iant@golang.org>

Error detection code copied from syscall, where presumably
we actually do it right.

Note that we throw the errno away.  The runtime doesn't use it.

Fixes #10052

Change-Id: I8de77dda6bf287276b137646c26b84fa61554ec8
Reviewed-on: https://go-review.googlesource.com/6571
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

Aconv is the pretty-printer for instruction opcodes like AMOVQ.
There was one for each architecture.
Make the space of A names have a different region for each architecture,
much as we did for the registers, so a single global Aconv function can
do the work. Each architecture registers its region as a slice of names
at a given offset.

The global names like CALL and JMP are now defined only once.

The A values are used for indexing tables, so make it easy to do the
indexing by making the offset maskable.

Remove a bunch of now-duplicated architecture-specific code.

Change-Id: Ib15647b7145a1c089e21e36543691a19e146b60e
Reviewed-on: https://go-review.googlesource.com/6620Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

grind's goto inliner moved a continue and changed its meaning. Oops.

Change-Id: Ifa2d3e1427036a606a069f356cd9b586ef22ec84
Reviewed-on: https://go-review.googlesource.com/6610Reviewed-by: Russ Cox <rsc@golang.org>

Change-Id: I3078385f5e7c92fbf99af7c4ae8918c86b9f86c9
Reviewed-on: https://go-review.googlesource.com/6500Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

Roll forward of 54efdc59. Better testing of the build on
darwin/amd64. There is still some variance between cmd/dist
and the Go tool for build tag handling.

Change-Id: I105669ae7f90c8c89b3839c04b182cff46be8dde
Reviewed-on: https://go-review.googlesource.com/6516
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

Previously, if there was a namespace defined on
a a>b tag, the namespace was ignored when
printing the parent elements. This fixes that,
and also fixes the racy behaviour of printerStack.trim
as discussed in https://go-review.googlesource.com/#/c/4152/10 .

Fixes #9796.

Change-Id: I75f97f67c08bbee151d1e0970f8462dd0f4511ef
Reviewed-on: https://go-review.googlesource.com/5910Reviewed-by: Nigel Tao <nigeltao@golang.org>

No functional changes.

This diff was generated as follows:

* Manually edit cmd/internal/gc/go.go to update types and group variables.
* Manually edit initialization in cmd/internal/gc/align.go--localized s/1/true.
* Manually fix the handling of sign in cmd/internal/gc/walk.go in func bounded (near line 4000).
* Manually update go.y and regenerate y.go.
* Run gofmt -r many times to do the rest, using https://gist.github.com/josharian/0f61dbb2dff81f938e70.

toolstash -cmp on the stdlib comes back green.

Change-Id: I19766ed551714e51b325133e7138818d117b3a9a
Reviewed-on: https://go-review.googlesource.com/6530Reviewed-by: Russ Cox <rsc@golang.org>

This CL makes the switch walking and typechecking code
more idiomatic and adds documentation.
It also removes all but one global variable.

No functional changes. Confirmed with toolstash -cmp on the stdlib.

Change-Id: Ic3f38acc66e906edd722498839aeb557863639cf
Reviewed-on: https://go-review.googlesource.com/6268Reviewed-by: Russ Cox <rsc@golang.org>

This change fixes a missing case that a routing address contains an
invalid address family label but it holds a valid length of address
structure.

Also makes test robust.

Fixes #10041.

Change-Id: I2480ba273929e859896697382d1a75b01a116b98
Reviewed-on: https://go-review.googlesource.com/6391Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This reverts commit 54efdc59.

Broken on darwin.

Change-Id: Ic74275f36d30975263340e2b4045226eae71b16a
Reviewed-on: https://go-review.googlesource.com/6514Reviewed-by: David Crawshaw <crawshaw@golang.org>

A future change will include an NSTimeZone hook so we can determine
the device's current time zone.

Change-Id: Ia4bd6b955e4cb720c518055541b66ff57a4dd303
Reviewed-on: https://go-review.googlesource.com/6511Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Run-TryBot: David Crawshaw <crawshaw@golang.org>

See golang.org/cl/6511.

Change-Id: I2145a42877ed6b78400f29c2ef18969870dab5c3
Reviewed-on: https://go-review.googlesource.com/6512Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>