Adam Langley [Wed, 17 Aug 2016 20:18:43 +0000 (13:18 -0700)]
crypto/hmac: don't test for length equality in Equal.
subtle.ConstantTimeCompare now tests the length of the inputs (although
it didn't when this code was written) so this test in crypto/hmac is now
superfluous.
Radu Berinde [Tue, 16 Aug 2016 12:05:39 +0000 (08:05 -0400)]
hash/crc32: improve the processing of the last bytes in the SSE4.2 code for AMD64
This commit improves the processing of the final few bytes in
castagnoliSSE42: instead of processing one byte at a time, we use all
versions of the CRC32 instruction to process 4 bytes, then 2, then 1.
The difference is only noticeable for small "odd" sized buffers.
We do the similar improvement for processing the first few bytes in
the case of unaligned buffer.
Fixing the test which was not actually verifying the results for
misaligned buffers (WriteString was creating an internal copy which
was aligned).
Adding benchmarks for length 15 (aligned and misaligned), results
below.
If we cannot infer the asm arch from the filename
or the build tags, assume that it is the
current build arch. Assembly files with no
restrictions ought to be usable on all arches.
Cherry Zhang [Tue, 16 Aug 2016 18:17:33 +0000 (14:17 -0400)]
cmd/compile: add more ARM64 optimizations
- Use machine instructions for uint64<->float conversions
- Do not enforce alignment on Zero/Move
ARM64 supports unaligned load/stores, but only aligned offset
or small offset can be encoded into instructions.
- Do combined loads
Change-Id: Iffca7dd0f13070b17b784861ce5a30af584680eb
Reviewed-on: https://go-review.googlesource.com/27086 Reviewed-by: David Chase <drchase@google.com>
Matthew Dempsky [Wed, 17 Aug 2016 15:57:15 +0000 (08:57 -0700)]
cmd/compile/internal/s390x: cleanup betypeinit
The Width{int,ptr,reg} assignments are no longer necessary since
golang.org/cl/21623. The other arch's betypeinit functions were
cleaned up, but apparently this one was missed.
Change-Id: I1c7f074d7864a561659c1f98aef604f57f285fd0
Reviewed-on: https://go-review.googlesource.com/27272
Run-TryBot: Matthew Dempsky <mdempsky@google.com> Reviewed-by: Michael Munday <munday@ca.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
math/rand: Document origin of cooked pseudo-random numbers
The Source provided by math/rand relies on an array of cooked
pseudo-random 63bit integers for seeding. The origin of these
numbers is undocumented.
Add a standalone program in math/rand folder that generates
the 63bit integer array as well as a 64bit version supporting
extension of the Source to 64bit pseudo-random number
generation while maintaining the current sequence in the
lower 63bit.
The code is largely based on the initial implementation of the
random number generator in the go repository by Ken Thompson
(revision 399).
Austin Clements [Wed, 17 Aug 2016 02:05:57 +0000 (22:05 -0400)]
runtime: fix check for vacuous page boundary rounding
sysUnused (e.g., madvise MADV_FREE) is only sensible to call on
physical page boundaries, so scavengelist rounds in the bounds of the
region being released to the nearest physical page boundaries.
However, if the region is smaller than a physical page and neither the
start nor end fall on a boundary, then rounding the start up to a page
boundary and the end down to a page boundary will result in end < start.
Currently, we only give up on the region if start == end, so if we
encounter end < start, we'll call madvise with a negative length and
the madvise will fail.
Issue #16644 gives a concrete example of this:
start = 0x1285ac000
end = 0x1285ae000 (1 8K page)
This leads to the rounded values
start = 0x1285b0000
end = 0x1285a0000
which leads to len = -65536.
Fix this by giving up on the region if end <= start, not just if
end == start.
Fixes #16644.
Change-Id: I8300db492dbadc82ac1ad878318b36bcb7c39524
Reviewed-on: https://go-review.googlesource.com/27230 Reviewed-by: Keith Randall <khr@golang.org>
Robert Griesemer [Wed, 17 Aug 2016 00:32:54 +0000 (17:32 -0700)]
cmd/compile: remove conditional code dealing with two export formats
This removes some scaffolding introduced pre-1.7, introduced to
fix an export format bug, and to minimize conflicts with older
formats. The currently deployed and recognized format is "v1",
so don't worry about other versions. This is a step towards a
better scheme for internal export format versioning.
For #16244.
Change-Id: Ic7cf99dd2a24ad5484cc54aed44fa09332c2cf72
Reviewed-on: https://go-review.googlesource.com/27205 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Robert Griesemer <gri@golang.org>
cmd/internal/obj: reduce per-architecture opcode space
s390x took up the last available chunk of int16 opcodes.
There are RISC-V and sparc64 ports in progress out of tree,
and there will likely be other architectures.
Reduce the opcode space to allow more architectures to
fit without increasing to int32.
This is the smallest power of two that accomodates all
existing architectures. All else being equal, smaller is
better--smaller numbers are easier to generate immediates
for and easier on the eyes when debugging.
Keith Randall [Wed, 6 Jul 2016 22:02:49 +0000 (15:02 -0700)]
runtime: fix map iterator concurrent map check
We should check whether there is a concurrent writer at the
start of every mapiternext, not just in mapaccessK (which is
only called during certain map growth situations).
Tests turned off by default because they are inherently flaky.
Keith Randall [Thu, 2 Jun 2016 19:41:42 +0000 (12:41 -0700)]
cmd/compile: use shorter versions of zero-extend ops
Only need to zero-extend to 32 bits and we get the top
32 bits zeroed for free.
Only the WQ change actually generates different code.
The assembler did this optimization for us in the other two cases.
But we might as well do it during SSA so -S output more closely
matches the actual generated instructions.
This optimization also helps range and slice.
The compiler must protect against pointers pointing
to the end of a slice/string. It does this by increasing
a pointer by either 0 or 1 * elemsize, based on a condition.
This CL optimizes away a jump in that code.
This CL triggers 382 times while compiling the standard library.
Updating code to utilize this optimization is left for future CLs.
Michael Pratt [Tue, 19 Jul 2016 04:59:14 +0000 (21:59 -0700)]
cmd/internal/obj: convert Aconv to a stringer
Now that assembler opcodes have their own type, they can have a true
stringer, rather than explicit calls to Aconv, which makes for nicer
format strings.
Give *recordingConn the correct WriteTo signature
to be an io.WriterTo. This makes vet happy.
It also means that it'll report errors,
which were previously being ignored.
container/list/list_test.go:274: self-assignment of e1 to e1
container/list/list_test.go:274: self-assignment of e4 to e4
container/list/list_test.go:282: self-assignment of e1 to e1
container/list/list_test.go:286: self-assignment of e1 to e1
container/list/list_test.go:286: self-assignment of e4 to e4
Cherry Zhang [Thu, 11 Aug 2016 13:54:04 +0000 (09:54 -0400)]
cmd/compile: remove nil check in accessing PAUTOHEAP variable
CL 23393 introduces PAUTOHEAP, and access of PAUTOHEAP variable is
rewritten to indirection of a PAUTO variable. Mark this variable
non-nil, so this indirection does not introduce extra nil checks.
This is preliminary work to unifying them.
Aside from Syscall9, all are identical.
Syscall9 has a netbsd/openbsd variant
and a dragonfly/freebsd variant.
Brad Fitzpatrick [Tue, 16 Aug 2016 05:05:00 +0000 (05:05 +0000)]
net/http: make Transport retry non-idempotent requests if no bytes written
If the server failed on us before we even tried to write any bytes,
it's safe to retry the request on a new connection, regardless of the
HTTP method/idempotence.
Jan Mercl [Tue, 2 Aug 2016 11:00:46 +0000 (13:00 +0200)]
go/token: Fix race in FileSet.PositionFor.
Methods of FileSet are documented to be safe for concurrent use by
multiple goroutines, so FileSet is protected by a mutex and all its
methods use it to prevent concurrent mutations. All methods of File that
mutate the respective FileSet, including AddLine, do also lock its
mutex, but that does not help when PositionFor is invoked concurrently
and reads without synchronization what AddLine mutates.
The change adds acquiring a RLock around the racy call of File.position
and the respective test.
Michael Hudson-Doyle [Thu, 11 Aug 2016 22:31:17 +0000 (10:31 +1200)]
cmd/link: when dynlinking, do not mangle short symbol names
When dynamically linking, a type symbol's name is replaced with a name based on
the SHA1 of the name as type symbol's names can be very long. However, this
can make a type's symbol name longer in some cases. So skip it in that case.
One of the symbols this changes the treatment of is 'type.string' and that fixes a
bug where -X doesn't work when dynamically linking.
Fixes #16671
Change-Id: If5269038261b76fb0ec52e25a9c1d64129631e3c
Reviewed-on: https://go-review.googlesource.com/26890
Run-TryBot: Michael Hudson-Doyle <michael.hudson@canonical.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org>
Robert Griesemer [Wed, 15 Jun 2016 00:35:36 +0000 (17:35 -0700)]
go/types: fix computation of initialization order
The old algorithm operated on a dependency graph that included
all objects (including functions) for simplicity: it was based
directly on the dependencies collected for each object during
type checking an object's initialization expression. It also
used that graph to compute the objects involved in an erroneous
initialization cycle.
Cycles that consist only of (mutually recursive) functions are
permitted in initialization code; so those cycles were silently
ignored if encountered. However, such cycles still inflated the
number of dependencies a variable might have (due to the cycle),
which in some cases lead to the wrong variable being scheduled
for initialization before the one with the inflated dependency
count.
Correcting for the cycle when it is found is too late since at
that point another variable may have already been scheduled.
The new algorithm computes the initialization dependency graph as
before but adds an extra pass during which functions are eliminated
from the graph (and their dependencies are "back-propagated").
This eliminates the problem of cycles only involving functions
(there are no functions).
When a cycle is found, the new code computes the cycle path from
the original object dependencies so it can still include functions
on the path as before, for the same detailed error message.
The new code also more clearly distinguishes between objects that
can be in the dependency graph (constants, variables, functions),
and objects that cannot, by introducing the dependency type, a new
subtype of Object. As a consequence, the dependency graph is smaller.
Fixes #10709.
Change-Id: Ib58d6ea65cfb279041a0286a2c8e865f11d244eb
Reviewed-on: https://go-review.googlesource.com/24131 Reviewed-by: Alan Donovan <adonovan@google.com>
Brad Fitzpatrick [Wed, 10 Aug 2016 19:46:48 +0000 (19:46 +0000)]
syscall: test Gettimeofday everywhere, not just on Darwin
The Darwin-only restriction was because we were late in the Go 1.7
cycle when the test was added.
In the process, I noticed Gettimeofday wasn't in the "unimplemented
midden heap" section of syscall_nacl.go, despite this line in the
original go1.txt:
pkg syscall, func Gettimeofday(*Timeval) error
So, add it, returning ENOSYS like the others.
Change-Id: Id7e02e857b753f8d079bee335c22368734e92254
Reviewed-on: https://go-review.googlesource.com/26772
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Quentin Smith <quentin@golang.org>
David Chase [Wed, 10 Aug 2016 18:44:57 +0000 (11:44 -0700)]
[dev.ssa] cmd/compile: PPC64, FP to/from int conversions.
Passes ssa_test.
Requires a few new instructions and some scratchpad
memory to move data between G and F registers.
Also fixed comparisons to be correct in case of NaN.
Added missing instructions for run.bash.
Removed some FP registers that are apparently "reserved"
(but that are also apparently also unused except for a
gratuitous multiplication by two when y = x+x would work
just as well).
Cherry Zhang [Wed, 10 Aug 2016 17:24:03 +0000 (13:24 -0400)]
[dev.ssa] cmd/compile, etc.: more ARM64 optimizations, and enable SSA by default
Add more ARM64 optimizations:
- use hardware zero register when it is possible.
- use shifted ops.
The assembler supports shifted ops but not documented, nor knows
how to print it. This CL adds them.
- enable fast division.
This was disabled because it makes the old backend generate slower
code. But with SSA it generates faster code.
Keith Randall [Thu, 11 Aug 2016 19:56:36 +0000 (12:56 -0700)]
[dev.ssa] cmd/compile: simplify 386+PIC+globals a bit
We shouldn't issue instructions like MOVL foo(SB), AX directly from the
SSA backend. Instead we should do LEAL foo(SB), AX; MOVL (AX), AX.
This simplifies obj logic because now only LEAL needs to be treated
specially. The register allocator uses the LEAL to in effect allocate
the temporary register required for the shared library thunk calls.
Also, the LEALs can now be CSEd. So code like
var g int
func f() { g += 5 }
Requires only one thunk call instead of 2.
Change-Id: Ib87d465f617f73af437445871d0ea91a630b2355
Reviewed-on: https://go-review.googlesource.com/26814
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
Keith Randall [Thu, 11 Aug 2016 16:49:48 +0000 (09:49 -0700)]
[dev.ssa] cmd/compile: fix fp constant loads for 386+PIC
In position-independent 386 code, loading floating-point constants from
the constant pool requires two steps: materializing the address of
the constant pool entry (requires calling a thunk) and then loading
from that address.
Before this CL, the materializing happened implicitly in CX, which
clobbered that register.
Change-Id: Id094e0fb2d3be211089f299e8f7c89c315de0a87
Reviewed-on: https://go-review.googlesource.com/26811
Run-TryBot: Keith Randall <khr@golang.org> Reviewed-by: David Crawshaw <crawshaw@golang.org> Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Cherry Zhang [Wed, 3 Aug 2016 15:47:40 +0000 (11:47 -0400)]
[dev.ssa] cmd/internal/obj/arm64: fix encoding constant into some instructions
When a constant can be encoded in a logical instruction (BITCON), do
it this way instead of using the constant pool. The BITCON testing
code runs faster than table lookup (using map):
(on AMD64 machine, with pseudo random input)
BenchmarkIsBitcon-4 300000000 4.04 ns/op
BenchmarkTable-4 50000000 27.3 ns/op
The equivalent C code of BITCON testing is formally verified with
model checker CBMC against linear search of the lookup table.
Also handle cases when a constant can be encoded in a MOV instruction.
In this case, materializa the constant into REGTMP without using the
constant pool.
When constants need to be added to the constant pool, make sure to
check whether it fits in 32-bit. If not, store 64-bit.
Both legacy and SSA compiler backends are happy with this.