When casting an ideal to complex{64,128}, for example during the
evaluation of

  var a = complex64(0) / 1e-50

we want the compiler to report a division-by-zero error if a divisor
would be zero after the cast.

We already do this for floats; for example

  var b = float32(0) / 1e-50

generates a 'division by zero' error at compile time (because
float32(1e-50) is zero, and the cast is done before performing the
division).

There's no such check in the path for complex{64,128} expressions, and
no cast is performed before the division in the evaluation of

  var a = complex64(0) / 1e-50

which compiles just fine.

This patch changes the convlit1 function so that complex ideals
components (real and imag) are correctly truncated to float{32,64}
when doing an ideal -> complex{64, 128} cast.

Fixes #11674

Change-Id: Ic5f8ee3c8cfe4c3bb0621481792c96511723d151
Reviewed-on: https://go-review.googlesource.com/37891
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

Move it to the x86 package, matching our handling
of deferreturn in x86 and arm.
While we're here, improve the concurrency safety
of both Plan9privates and deferreturn
by eagerly initializing them in instinit.

Updates #15756

Change-Id: If3b1995c1e4ec816a5443a18f8d715631967a8b1
Reviewed-on: https://go-review.googlesource.com/40408
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

A recent performance improvement for PPC64.rules introduced a
regression for the case where the size of a move is <= 8 bytes
and the value used in the offset field of the instruction is not
aligned correctly for the instruction. In the cases where this happened,
the assembler was not detecting the incorrect offset and still generated
the instruction even though it was invalid.

This fix changes the PPC64.rules for the moves that are now failing
to include the correct alignment checks, along some additional testcases
for gc/ssa for the failing alignments.

I will add a fix to the assembler to detect incorrect offsets in
another CL.

This fixes #19907

Change-Id: I3d327ce0ea6afed884725b1824f9217cef2fe6bf
Reviewed-on: https://go-review.googlesource.com/40290Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
Reviewed-by: David Chase <drchase@google.com>

It is zeroed pointlessly and never read.

Change-Id: I65390501a878f545122ec558cb621b91e394a538
Reviewed-on: https://go-review.googlesource.com/40406
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Curently the vendor paths are not always searched for imports if
the compiler is gccgo.  This change generates the vendor paths
and adds them with -I as arguments to the gccgo compile.

Fixes #15628

Change-Id: I318accbbbd8e6af45475eda399377455a3565880
Reviewed-on: https://go-review.googlesource.com/40432
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

It is only used once and never written to.
Switch to a local constant instead.

Change-Id: Icdd84e47b81f0de44ad9ed56ab5f4f91df22e6b6
Reviewed-on: https://go-review.googlesource.com/40405
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

These are unused after CLs 39922, 40252, 40370, 40371, and 40372.

Change-Id: I76f9276c581067a8cb555de761550d960f6e39b8
Reviewed-on: https://go-review.googlesource.com/40404
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

Continues outside of a loop are not allowed. Most of these possibilities
were tested in label1.go, but one was missing - a plain continue in a
switch/select but no enclosing loop.

This used to error with a "continue not in loop" in 1.8, but recently
was broken by c03e75e5. In particular, innerloop does not only account
for loops, but also for switches and selects. Swap it by bools that
track whether breaks and continues should be allowed.

While at it, improve the wording of errors for breaks that are not where
they should be. Change "loop" by "loop, switch, or select" since they
can be used in any of those.

And add tests to make sure this isn't broken again. Use a separate func
since I couldn't get the compiler to crash on f() itself, possibly due
to the recursive call on itself.

Fixes #19934.

Change-Id: I8f09c6c2107fd95cac50efc2a8cb03cbc128c35e
Reviewed-on: https://go-review.googlesource.com/40357
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>

Previously, int values of #define macro are retrieved from DWARF via enums.
Currently, those values are retrieved from symbol tables.
It seems that previous code is unused.

Change-Id: Id76c54baa46d6196738ea35aebd5de99b05b9bf8
Reviewed-on: https://go-review.googlesource.com/40072Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

The reflect package can be used to create new types at runtime, these
types will have runtime._type entries describing them but no entry in
debug_info (obviously).

A debugger that wanted to print the value of variables with such types
will have to read the runtime._type directly, however the
"specializations" of runtime._type (runtime.slicetype, runtime.maptype,
etc) are not exported to debug_info, besides runtime.interfacetype.

All those types (i.e. runtime.slicetype, runtime.maptype, etc) should
be exported to debug_info so that debuggers don't have to hard-code
their description.

Fixes #19602

Change-Id: I086d523a4421a4ed964e16bc3c2274319a98b45b
Reviewed-on: https://go-review.googlesource.com/38350Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Prevent a crash if the same type in two plugins had a recursive
definition, either by referring to a pointer to itself or a map existing
with the type as a value type (which creates a recursive definition
through the overflow bucket type).

Fixes #19258

Change-Id: Iac1cbda4c5b6e8edd5e6859a4d5da3bad539a9c6
Reviewed-on: https://go-review.googlesource.com/40292
Run-TryBot: Todd Neal <todd@tneal.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

open modified the plugin symbols map while ranging over it. This is
normally harmless, except that the operations performed were not
idempotent leading to function pointers being corrupted.

Fixes #19269

Change-Id: I4b6eb1d45567161412e4a34b41f1ebf647bcc942
Reviewed-on: https://go-review.googlesource.com/40431
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>

This was unintentionally emptied rather than removed in 9417c022.

Change-Id: Ie6fdcf7ef55e58f12e2a2750ab448aa2d9f94d15
Reviewed-on: https://go-review.googlesource.com/40413Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Fixes #19628

Change-Id: I19baf694c66aaca8e0d95297c97aacb40db24c47
Reviewed-on: https://go-review.googlesource.com/40250Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>

Form a new method pattern where *driverConn and
release functions are passed into the method.
They are named DB.execDC, DB.queryDC, DB.beginDC. This
allows more code to be de-duplicated when starting
queries.

The Stmt creation and management code are untouched.

Change-Id: I24c853531e511d8a4bc1f53dd4dbdf968763b4e7
Reviewed-on: https://go-review.googlesource.com/39630
Run-TryBot: Daniel Theophanes <kardianos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

For details see the discussion on the issue below.

RotateLeft functions can now be inlined because the don't panic
anymore for negative rotation counts.

name            old time/op  new time/op  delta
RotateLeft-8    6.72ns ± 2%  1.86ns ± 0%  -72.33%  (p=0.016 n=5+4)
RotateLeft8-8   4.41ns ± 2%  1.67ns ± 1%  -62.15%  (p=0.008 n=5+5)
RotateLeft16-8  4.46ns ± 6%  1.65ns ± 0%  -63.06%  (p=0.008 n=5+5)
RotateLeft32-8  4.50ns ± 5%  1.67ns ± 1%  -62.86%  (p=0.008 n=5+5)
RotateLeft64-8  4.54ns ± 1%  1.85ns ± 1%  -59.32%  (p=0.008 n=5+5)

https://perf.golang.org/search?q=upload:20170411.4

(Measured on 2.3 GHz Intel Core i7 running macOS 10.12.3.)

For #18616.

Change-Id: I0828d80d54ec24f8d44954a57b3d6aeedb69c686
Reviewed-on: https://go-review.googlesource.com/40394Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Also reformat tables.

Fixes #19889

Change-Id: I05083d2bab8bca46c4e22a415eb9b73513df6994
Reviewed-on: https://go-review.googlesource.com/40071Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

sort.Slice was added in Go 1.8.
It's nice to use, and faster than sort.Sort,
so it'd be nice to be able to use it in the toolchain.
This CL adds obj.SortSlice, which is sort.Slice,
but with a slower fallback version for bootstrapping.

This CL also includes a single demo+test use.

Change-Id: I2accc60b61f8e48c8ab4f1a63473e3b87af9b691
Reviewed-on: https://go-review.googlesource.com/40114
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

In the newest AES implementation in asm for ppc64le, this part

MOVW $·rcon(SB), PTR

should be

MOVD $·rcon(SB), PTR

since it is loading a doubleword value into PTR.

Change-Id: I7e3d6ad87a2237015aeeb30c68fb409a18f2801c
Reviewed-on: https://go-review.googlesource.com/40298Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com>

OpenBSD 6.0 and later have support for PT_TLS in ld.so(1). Now that OpenBSD
6.1 has been released, OpenBSD 5.9 is no longer officially supported and Go
can start generating PT_TLS for OpenBSD cgo binaries. This also allows us
to remove the workarounds in the OpenBSD cgo runtime.

This change also removes the environ and progname exports - these are now
provided directly by ld.so(1) itself.

Fixes #19932

Change-Id: I42e75ef9feb5dcd4696add5233497e3cbc48ad52
Reviewed-on: https://go-review.googlesource.com/40331Reviewed-by: Ian Lance Taylor <iant@golang.org>

Noticed by Cherry while reviewing CL 40252.

The alternative to this is to place t on the stack, like

t := obj.Prog{Ctxt: ctxt}

However, there are only a couple of places where we
manually construct Progs, which is useful.

This isn't hot enough code to warrant
breaking abstraction layers to avoid an allocation.

Passes toolstash-check.

Change-Id: I46c79090b60641c90ee977b750ba5c708aca8ecf
Reviewed-on: https://go-review.googlesource.com/40373
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

CL 39922 made the arm assembler concurrency-safe.
This CL does the same, but for s390x.
The approach is similar: introduce ctxtz to hold
function-local state and thread it through
the assembler as necessary.

One race remains after this CL, similar to CL 40252.

That race is conceptually unrelated to this refactoring,
and will be addressed in a separate CL.

Passes toolstash-check -all.

Updates #15756

Change-Id: Iabf17aa242b70c0b078c2e85dae3d93a5e512372
Reviewed-on: https://go-review.googlesource.com/40371
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <munday@ca.ibm.com>

CL 39922 made the arm assembler concurrency-safe.
This CL does the same, but for ppc64.
The approach is similar: introduce ctxt9 to hold
function-local state and thread it through
the assembler as necessary.

One race remains after this CL, similar to CL 40252.

That race is conceptually unrelated to this refactoring,
and will be addressed in a separate CL.

Passes toolstash-check -all.

Updates #15756

Change-Id: Icc37d9a971bed2184c8e66b1a64f4f2e556dc207
Reviewed-on: https://go-review.googlesource.com/40372
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

CL 39922 made the arm assembler concurrency-safe.
This CL does the same, but for arm64.
The approach is similar: introduce ctxt7 to hold
function-local state and thread it through
the assembler as necessary.

One race remains after this CL, deep in aclass,
in the check that a Prog does not take the address
of a TLS variable.

That race is conceptually unrelated to this refactoring,
and will be addressed in a separate CL.

Passes toolstash-check -all.

Updates #15756

Change-Id: Icab1ef70008468f9a5b8bf728a77c4520bbcb67d
Reviewed-on: https://go-review.googlesource.com/40252
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

CL 39922 made the arm assembler concurrency-safe.
This CL does the same, but for mips.
The approach is similar: introduce ctxt0 to hold
function-local state and thread it through
the assembler as necessary.

One race remains after this CL, similar to CL 40252.

That race is conceptually unrelated to this refactoring,
and will be addressed in a separate CL.

Passes toolstash-check -all.

Updates #15756

Change-Id: I2c54a889aa448a4476c9a75da4dd94ef69657b16
Reviewed-on: https://go-review.googlesource.com/40370
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

The hardware divider is an optional component of ARMv7. This patch
detects whether it is available in runtime and use it or not.

1. The hardware divider is detected at startup and a flag is set/clear
   according to a perticular bit of runtime.hwcap.
2. Each call of runtime.udiv will check this flag and decide if
   use the hardware division instruction.

A rough test shows the performance improves 40-50% for ARMv7. And
the compatibility of ARMv5/v6 is not broken.

fixes #19118

Change-Id: Ic586bc9659ebc169553ca2004d2bdb721df823ac
Reviewed-on: https://go-review.googlesource.com/37496
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

These are never accessed.

Change-Id: I45975972d19d1f263f6545c9ed648511501094c6
Reviewed-on: https://go-review.googlesource.com/40315
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Current code could return a non-nil os.FileInfo even if there is an error.
This is a bit incompatible with Stat on other OSes.

Change-Id: I37b608da234f957bb89b82509649de78ccc70bbb
Reviewed-on: https://go-review.googlesource.com/40330
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

This makes the core Flushplist loop clearer.

We may also want to move the Sym initialization
much earlier in the compiler (see discussion on
CL 40254), for which this paves the way.

While we're here, eliminate package log in favor of ctxt.Diag.

Passes toolstash-check -all.

Updates #15756

Change-Id: Ieaf848d196764a5aa82578b689af7bc6638c385a
Reviewed-on: https://go-review.googlesource.com/40313
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>

Changing mheap_.arena_used requires several steps that are currently
repeated multiple times in mheap_.sysAlloc. Consolidate these into a
single function.

In the future, this will also make it easier to add other auxiliary VM
structures.

Change-Id: Ie68837d2612e1f4ba4904acb1b6b832b15431d56
Reviewed-on: https://go-review.googlesource.com/40151
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

Change-Id: Ic9be3249e76da7e86cc41baa88935249a94e4a16
Reviewed-on: https://go-review.googlesource.com/40073
Run-TryBot: Mikio Hara <mikioh.mikioh@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

This avoids false positives
like those found in #19880.

Fixes #19880

Change-Id: I583c16cc3c71e7462a72500db9ea2547c468f8c1
Reviewed-on: https://go-review.googlesource.com/40255
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Extract out some common boiler plate logic.

Passes toolstash-check -all.

Change-Id: Iddc8a733af8262558f56d13c91d9c27ee0d61330
Reviewed-on: https://go-review.googlesource.com/40253
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Fixes #19911

Change-Id: Ib2b2505fe31ce00c6ffc021a0fe5df510633b44b
Reviewed-on: https://go-review.googlesource.com/40251
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

Copy the documentation and example from cmd/go.

Fixes #18840.

Change-Id: Id8022762b48576fb4031de05287d07a6ed23f480
Reviewed-on: https://go-review.googlesource.com/37440Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

For google/pprof#132.

Change-Id: I73785bc8662565ff7b2fac66e23497dd06fc25b6
Reviewed-on: https://go-review.googlesource.com/40231
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

The existing implementation does not provide a useful error message
if a negative offset is passed in File.ReadAt or File.WriteAt. This
change is to return descriptive errors. An error of type *PathError
is returned to keep it consistent with rest of the code.

There is no need to add an exported error variable since it's used only
in one file.

Fixes #19031

Change-Id: Ib94cab0afae8c5fe4dd97ed2887018a09b9f4538
Reviewed-on: https://go-review.googlesource.com/39136Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Users (like myself) may be tempted to think the higher-numbered curve
is somehow better or more secure, but P256 is currently the best
ECDSA implementation, due to its better support in TLS clients, and a
constant time implementation.

For example, sites that present a certificate signed with P521
currently fail to load in Chrome stable, and the error on the Go side
says simply "remote error: tls: illegal parameter".

Fixes #19901.

Change-Id: Ia5e689e7027ec423624627420e33029c56f0bd82
Reviewed-on: https://go-review.googlesource.com/40211Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

I plan to use c as a consistent local variable
in this packages. Rename most variables named c,
excepting only some simple functions in asm9.go.

Changes prepared with gorename.

Passes toolstash-check -all.

Updates #15756

Change-Id: If79baac43fca68fad1076e1ff23ae87c2ba638e4
Reviewed-on: https://go-review.googlesource.com/40172
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

Move global state from obj.Link
to a new function-local state struct arm.ctxt5.

This ends up being cleaner than threading
all the state through as parameters; there's a lot of it.
While we're here, move newprog from a parameter to ctxt5.

We reserve the variable name c for ctxt5,
so a few local variables named c have been renamed.

Instead of lazily initializing deferreturn
and Sym_div and friends, initialize them up front.

Passes toolstash-check -all.

Updates #15756

Change-Id: Ifb4e4b9879e4e1f25e6168d8b7b2a25a3390dc11
Reviewed-on: https://go-review.googlesource.com/39922
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>