Robert Griesemer [Tue, 13 Mar 2018 23:08:16 +0000 (16:08 -0700)]
cmd/compile: document new line directives
Fixes #24183.
Change-Id: I5ef31c4a3aad7e05568b7de1227745d686d4aff8
Reviewed-on: https://go-review.googlesource.com/100462 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Tobias Klauser [Wed, 14 Mar 2018 15:35:22 +0000 (15:35 +0000)]
runtime, syscall: add RawSyscall6 on Solaris and make it panic
The syscall package currently declares RawSyscall6 for every GOOS, but
does not define it on Solaris. This leads to code using said function
to compile but it will not link. Fix it by adding RawSyscall6 and make
it panic.
Also remove the obsolete comment above runtime.syscall_syscall as
pointed out by Aram.
Alberto Donizetti [Wed, 14 Mar 2018 10:07:06 +0000 (11:07 +0100)]
test/codegen: port all small memmove tests to codegen
This change ports all the remaining tests checking that small memmoves
are replaced with MOVs to the new codegen test harness, and deletes
them from the asm_test file.
Change-Id: I01c94b441e27a5d61518035af62d62779dafeb56
Reviewed-on: https://go-review.googlesource.com/100476
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
David du Colombier [Wed, 14 Mar 2018 12:36:31 +0000 (13:36 +0100)]
runtime: don't use floating point in findnull on Plan 9
In CL 98015, findnull was rewritten so it uses bytes.IndexByte.
This broke the build on plan9/amd64 because the implementation
of bytes.IndexByte on AMD64 relies on SSE instructions while
floating point instructions are not allowed in the note handler.
This change fixes findnull by using the former implementation
on Plan 9, so it doesn't use bytes.IndexByte.
Fixes #24387.
Change-Id: I084d1a44d38d9f77a6c1ad492773f0a98226be16
Reviewed-on: https://go-review.googlesource.com/100577
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Rob Pike <r@golang.org>
Tobias Klauser [Tue, 13 Mar 2018 16:45:17 +0000 (17:45 +0100)]
test: check that size argument errors are emitted at call site
Add tests for the "negative size argument in make.*" and "size argument
too large in make.*" error messages to appear at call sites in case the
size is a const defined on another line.
As suggested by Matthew in a comment on CL 69910.
Change-Id: I5c33d4bec4e3d20bb21fe8019df27999997ddff3
Reviewed-on: https://go-review.googlesource.com/100395 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Giovanni Bajo [Sat, 10 Mar 2018 10:17:05 +0000 (11:17 +0100)]
cmd/compile: remove BTQconst rule
This rule is meant for code optimization, but it makes other rules
potentially more complex, as they need to cope with the fact that
a 32-bit op (BTLconst) can appear everywhere a 64-bit rule maches.
Move the optimization to opcode expansion instead. Tests will be
added in following CL.
Change-Id: Ica5ef291e7963c4af17c124d4a2869e6c8f7b0c7
Reviewed-on: https://go-review.googlesource.com/99995 Reviewed-by: Keith Randall <khr@golang.org>
Daniel Martí [Tue, 13 Mar 2018 20:37:05 +0000 (20:37 +0000)]
cmd/asm: VPERMQ's imm8 arg is an uint8
The imm8 argument consists of 4 2-bit indices, so it can take values up
to $255. However, the assembler was treating it as Yi8, which reads
"fits in int8". Add a Yu8 variant, to also keep backwards compatibility
with negative values possible with Yi8.
Fixes #24378.
Change-Id: I24ddb19c219b54d039a6c1bcdb903717d1c7c3b8
Reviewed-on: https://go-review.googlesource.com/100475
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>
Carlos Eduardo Seo [Wed, 10 Jan 2018 17:29:50 +0000 (15:29 -0200)]
cmd/internal/obj/ppc64: implement full operand support for l*arx instructions
The current implementation of l*arx instructions does not accept non-zero
offsets in RA nor the EH field. This change adds full functionality to those
instructions.
Cherry Zhang [Mon, 12 Mar 2018 23:28:21 +0000 (19:28 -0400)]
cmd/internal/obj/arm64: support logical instructions targeting RSP
Logical instructions can have RSP as its destination. Support it.
Note that the two-operand form, like "AND $1, RSP", which is
equivalent to the three-operand form "AND $1, RSP, RSP", is
invalid, because the source register is not allowed to be RSP.
Also note that instructions that set the conditional flags, like
ANDS, cannot target RSP. Because of this, we split out the optab
entries of AND et al. and ANDS et al.
Merge the optab entries of BIC et al. to AND et al., because they
are same.
David Chase [Fri, 9 Mar 2018 22:33:29 +0000 (17:33 -0500)]
cmd/compile: fix failure to reset reused bit of storage
This is the "3rd bug" that caused compilations to sometimes
produce different results when dwarf location lists were
enabled.
A loop had not been properly rewritten in an earlier
optimization CL, and it accessed uninitialized data,
which was deterministically perhaps wrong when single
threaded, but variably wrong when multithreaded.
jimmyfrasche [Mon, 12 Mar 2018 00:15:44 +0000 (17:15 -0700)]
go/token: add example for retrieving Position from Pos
There are few uses for the majority of the API in go/token for the
average user. The exception to this is getting the filename, line, and
column information from a token.Pos (reported and absolute. This is
straightforward but figuring out how to do it requires combing through
a lot of documentation. This example makes it more easily discoverable.
Updates #24352.
Change-Id: I0a45da6173b3dabebf42484bbbed30d9e5e20e01
Reviewed-on: https://go-review.googlesource.com/100058 Reviewed-by: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Vladimir Kuzmin [Fri, 2 Feb 2018 05:33:56 +0000 (21:33 -0800)]
cmd/compile: avoid extra mapaccess in "m[k] op= r"
Currently, order desugars map assignment operations like
m[k] op= r
into
m[k] = m[k] op r
which in turn is transformed during walk into:
tmp := *mapaccess(m, k)
tmp = tmp op r
*mapassign(m, k) = tmp
However, this is suboptimal, as we could instead produce just:
*mapassign(m, k) op= r
One complication though is if "r == 0", then "m[k] /= r" and "m[k] %=
r" will panic, and they need to do so *before* calling mapassign,
otherwise we may insert a new zero-value element into the map.
It would be spec compliant to just emit the "r != 0" check before
calling mapassign (see #23735), but currently these checks aren't
generated until SSA construction. For now, it's simpler to continue
desugaring /= and %= into two map indexing operations.
isharipo [Fri, 9 Mar 2018 20:09:46 +0000 (23:09 +0300)]
cmd/compile/internal/ssa: emit IMUL3{L/Q} for MUL{L/Q}const on x86
cmd/asm now supports three-operand form of IMUL,
so instead of using IMUL with resultInArg0, emit IMUL3 instruction.
This results in less redundant MOVs where SSA assigns
different registers to input[0] and dst arguments.
Note: these have exactly the same encoding when reg0=reg1:
IMUL3x $const, reg0, reg1
IMULx $const, reg
Two-operand IMULx is like a crippled IMUL3x, with dst fixed to input[0].
This is why we don't bother to generate IMULx for the case where
dst is the same as input[0].
Change-Id: I4becda475b3dffdd07b6fdf1c75bacc82af654e4
Reviewed-on: https://go-review.googlesource.com/99656
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Giovanni Bajo <rasky@develer.com> Reviewed-by: Keith Randall <khr@golang.org>
erifan01 [Wed, 25 Oct 2017 09:22:09 +0000 (09:22 +0000)]
math/big: optimize shlVU and shrVU on arm64
This CL implements shlVU and shrVU with arm64 HW instructions "LDP" and "STP" to reduce load cost,
it also removes unnecessary checks on the number of shifts for better performance.
Daniel Martí [Sat, 10 Mar 2018 16:50:16 +0000 (16:50 +0000)]
cmd: re-generate all stringer files
The tool has gotten better over time, so re-generating the files brings
some advantages like fewer objects, dropping the use of fmt, and
dropping unnecessary bounds checks.
While at it, add the missing go:generate line for obj.AddrType.
Daniel Martí [Sat, 3 Mar 2018 19:53:53 +0000 (19:53 +0000)]
cmd/internal/test2json: support subtests containing colons
The "updates" lines, such as RUN, do not contain a colon. However,
test2json looked for one anyway, meaning that it would be thrown off if
it encountered a line like:
=== RUN TestWithColons/[::1]
In that case, it must not use the first colon it encounters to separate
the action from the test name.
Fixes #23920.
Change-Id: I82eff23e24b83dae183c0cf9f85fc5f409f51c25
Reviewed-on: https://go-review.googlesource.com/98445
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
As before, //-style line directives must start in column 1.
/*-style line directives may be placed anywhere in the code.
In both cases, the specified position applies to the character
immediately following the comment; for line comments that is
the first character on the next line (after the newline of the
comment).
File.AddLineInfo(offset int, filename string, line int)
by adding a column parameter.
Adjusted token.Position computation is changed to take into account
column information if provided via a line directive: A (line-directive)
relative position will have a non-zero column iff the line directive
specified a column; if the position is on the same line as the line
directive, the column is relative to the specified column (otherwise
it is relative to the line beginning). See also #24183.
Finally, Position.String() has been adjusted to not print a column
value if the column is unknown (== 0).
Fixes #24143.
Change-Id: I5518c825ad94443365c049a95677407b46ba55a1
Reviewed-on: https://go-review.googlesource.com/97795 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Ben Shi [Thu, 8 Mar 2018 10:33:37 +0000 (10:33 +0000)]
cmd/compile: fix an issue in MNEG of ARM64
There are two less optimized SSA rules in my previous CL
https://go-review.googlesource.com/c/go/+/95075 .
This CL fixes that issue and a test case gets about 10%
performance improvement.
name old time/op new time/op delta
MNEG-4 263µs ± 3% 235µs ± 3% -10.53% (p=0.000 n=20+20)
(https://github.com/benshi001/ugo1/blob/master/mneg_7_test.go)
Austin Clements [Fri, 9 Mar 2018 21:12:40 +0000 (16:12 -0500)]
runtime: fix abort handling on arm64
The implementation of runtime.abort on arm64 currently branches to
address 0, which results in a signal from PC 0, rather than from
runtime.abort, so the runtime fails to recognize it as an abort.
Fix runtime.abort on arm64 to read from address 0 like what other
architectures do and recognize this in the signal handler.
Ilya Tocar [Thu, 1 Mar 2018 22:52:27 +0000 (16:52 -0600)]
runtime: use bytes.IndexByte in findnull
bytes.IndexByte is heavily optimized. Use it in findnull.
This is second attempt, similar to CL97523.
In this version we never call IndexByte on region of memory,
that crosses page boundary. A bit slower than CL97523,
but still fast:
name old time/op new time/op delta
GoString-6 164ns ± 2% 118ns ± 0% -28.00% (p=0.000 n=10+6)
findnull is also used in gostringnocopy,
which is used in many hot spots in the runtime.
Alberto Donizetti [Wed, 7 Mar 2018 11:54:28 +0000 (12:54 +0100)]
test/codegen: add README file for the codegen test harness
This change adds a README file inside the test/codegen directory,
explaining how to run the codegen tests and the syntax of the regexps
comments used to match assembly instructions.
Change-Id: Ica4eb3ffa9c6975371538cc8ae0ac3c1a3a03baf
Reviewed-on: https://go-review.googlesource.com/99156 Reviewed-by: Keith Randall <khr@golang.org>
Daniel Martí [Thu, 8 Mar 2018 18:47:07 +0000 (18:47 +0000)]
encoding/gob: work around TestFuzzOneByte panic
The index 248 results in the decoder calling reflect.MakeMapWithSize
with a size of 14754407682 - just under 15GB - which ends up in a
runtime out of memory panic after some recent runtime changes on
machines with 8GB of memory.
Until that is fixed in either runtime or gob, skip the troublesome
index.
Updates #24308.
Change-Id: Ia450217271c983e7386ba2f3f88c9ba50aa346f4
Reviewed-on: https://go-review.googlesource.com/99655
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
Borrowed from cmd/compile, TestSizeof ensures
that the size of important types doesn't change unexpectedly.
It also helps reviewers see the impact of intended changes.
Vladimir Kuzmin [Thu, 8 Mar 2018 03:46:54 +0000 (19:46 -0800)]
net: optimize IP.String for IPv4
This is optimization is only for IPv4. It allocates a result buffer and
writes the IPv4 octets as dotted decimal into it before converting
it to a string just once, reducing allocations.
Benchmark shows performance improvement:
name old time/op new time/op delta
IPString/IPv4-8 284ns ± 4% 144ns ± 6% -49.35% (p=0.000 n=19+17)
IPString/IPv6-8 1.34µs ± 5% 1.14µs ± 5% -14.37% (p=0.000 n=19+20)
name old alloc/op new alloc/op delta
IPString/IPv4-8 24.0B ± 0% 16.0B ± 0% -33.33% (p=0.000 n=20+20)
IPString/IPv6-8 232B ± 0% 224B ± 0% -3.45% (p=0.000 n=20+20)
name old allocs/op new allocs/op delta
IPString/IPv4-8 3.00 ± 0% 2.00 ± 0% -33.33% (p=0.000 n=20+20)
IPString/IPv6-8 12.0 ± 0% 11.0 ± 0% -8.33% (p=0.000 n=20+20)
Tobias Klauser [Fri, 9 Mar 2018 12:27:09 +0000 (13:27 +0100)]
runtime: fix comment for hwcap on linux/arm
hwcap is set in archauxv, setup_auxv no longer exists.
Change-Id: I0fc9393e0c1c45192e0eff4715e9bdd69fab2653
Reviewed-on: https://go-review.googlesource.com/99779 Reviewed-by: Ian Lance Taylor <iant@golang.org>
Jean de Klerk [Wed, 21 Feb 2018 01:26:57 +0000 (17:26 -0800)]
cmd/go: briefly document test caching in go test -h output
Fixes #23971
Change-Id: I073f278cc058aa15a23c0ea06292c02d50a3df21
Reviewed-on: https://go-review.googlesource.com/95582 Reviewed-by: Ian Lance Taylor <iant@golang.org> Reviewed-by: Rob Pike <r@golang.org>
Alberto Donizetti [Thu, 8 Mar 2018 16:43:55 +0000 (17:43 +0100)]
test/codegen: port math/bits.RotateLeft tests to codegen
Only RotateLeft{64,32} were tested, and just for ppc64. This CL adds
tests for RotateLeft{64,32,16,8} on arm64 and amd64/386, for the cases
where the calls are actually instrinsified.
RotateLeft tests (the last ones for math/bits functions) are deleted
from asm_test.
This CL also adds a space between the "//" and the arch name in the
comments, to uniform this file to the style used in all the other
files.
Change-Id: Ifc2a27261d70bcc294b4ec64490d8367f62d2b89
Reviewed-on: https://go-review.googlesource.com/99596 Reviewed-by: Giovanni Bajo <rasky@develer.com>
Hana Kim [Fri, 2 Mar 2018 20:52:30 +0000 (15:52 -0500)]
cmd/trace: remove unrelated arrows in task-oriented traceview
Also grey out instants that represent events occurred outside the
task's span. Furthermore, if the unrelated instants represent user
annotation events but not for the task of the interest, skip rendering
completely.
This helps users to focus on the task-related events better.
Robert Griesemer [Fri, 9 Mar 2018 00:06:16 +0000 (16:06 -0800)]
go/printer: simplify handling of line directives
Strangely enough, the existing implementation used adjusted (by line
directives) source positions to determine layout and thus required
position corrections when printing a line directive.
Instead, just use the unadjusted, absolute source positions and then
printing a line directive doesn't require any adjustments, only some
care to make sure it remains in column 1 as before.
The new code doesn't need to parse line directives anymore and simply
ensures that comments with the //line prefix and starting in column 1
remain in that position. That is a slight change from the old behavior
(which ignored incorrect line directives, e.g. because they had an
invalid line number) but unlikely to show up in real code.
This is prep work for handling of line directives that also specify
columns (which now won't require much special handling anymore).
For #24143.
Change-Id: I07eb2e1b35b37337e632e3dbf5b70c783c615f8a
Reviewed-on: https://go-review.googlesource.com/99621 Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Austin Clements [Thu, 8 Mar 2018 22:48:22 +0000 (17:48 -0500)]
runtime: explain and enforce that _panic values live on the stack
It's a bit mysterious that _defer.sp is a uintptr that gets
stack-adjusted explicitly while _panic.argp is an unsafe.Pointer that
doesn't, but turns out to be critically important when a deferred
function grows the stack before doing a recover.
Add a comment explaining that this works because _panic values live on
the stack. Enforce this by marking _panic go:notinheap.
Austin Clements [Thu, 18 Jan 2018 22:33:04 +0000 (17:33 -0500)]
runtime: ensure abort actually crashes the process
On all non-x86 arches, runtime.abort simply reads from nil.
Unfortunately, if this happens on a user stack, the signal handler
will dutifully turn this into a panicmem, which lets user defers run
and which user code can even recover from.
To fix this, add an explicit check to the signal handler that turns
faults in abort into hard crashes directly in the signal handler. This
has the added benefit of giving a register dump at the abort point.
Austin Clements [Wed, 17 Jan 2018 20:51:09 +0000 (15:51 -0500)]
runtime: call abort instead of raw INT $3 or bad MOV
Everything except for amd64, amd64p32, and 386 currently defines and
uses an abort function. This CL makes these match. The next CL will
recognize the abort function to make this more useful.
Austin Clements [Fri, 12 Jan 2018 17:39:22 +0000 (12:39 -0500)]
runtime: make throw safer to call
Currently, throw may grow the stack, which means whenever we call it
from a context where it's not safe to grow the stack, we first have to
switch to the system stack. This is pretty easy to get wrong.
Fix this by making throw switch to the system stack so it doesn't grow
the stack and is hence safe to call without a system stack switch at
the call site.
The only thing this complicates is badsystemstack itself, which would
now go into an infinite loop before printing anything (previously it
would also go into an infinite loop, but would at least print the
error first). Fix this by making badsystemstack do a direct write and
then crash hard.
Austin Clements [Thu, 18 Jan 2018 21:36:20 +0000 (16:36 -0500)]
runtime: move unrecoverable panic handling to the system stack
Currently parts of unrecoverable panic handling (notably, printing
panic messages) can happen on the user stack. This may grow the stack,
which is generally fine, but if we're handling a runtime panic, it's
better to do as little as possible in case the runtime is in an
inconsistent state.
Hence, this commit rearranges the handling of unrecoverable panics so
that it's done entirely on the system stack.
This is mostly a matter of shuffling code a bit so everything can move
into a systemstack block. The one slight subtlety is in the "panic
during panic" case, where we now depend on startpanic_m's caller to
print the stack rather than startpanic_m itself. To make this work,
startpanic_m now returns a boolean indicating that the caller should
avoid trying to print any panic messages and get right to the stack
trace. Since the caller is already in a position to do this, this
actually simplifies things a little.
Austin Clements [Thu, 11 Jan 2018 21:32:02 +0000 (16:32 -0500)]
cmd/compile: add fence-post implications to prove
This adds four new deductions to the prove pass, all related to adding
or subtracting one from a value. This is the first hint of actual
arithmetic relations in the prove pass.
The most effective of these is
x-1 >= w && x > min ⇒ x > w
This helps eliminate bounds checks in code like
if x > 0 {
// do something with s[x-1]
}
Altogether, these deductions prove an additional 260 branches in std
and cmd. Furthermore, they will let us eliminate some tricky
compiler-inserted panics in the runtime that are interfering with
static analysis.
Fixes #23354.
Change-Id: I7088223e0e0cd6ff062a75c127eb4bb60e6dce02
Reviewed-on: https://go-review.googlesource.com/87480 Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Alexandru Moșoi <alexandru@mosoi.ro>
Austin Clements [Wed, 10 Jan 2018 21:28:58 +0000 (16:28 -0500)]
cmd/compile: make prove pass use unsatisfiability
Currently the prove pass uses implication queries. For each block, it
collects the set of branch conditions leading to that block, and
queries this fact table for whether any of these facts imply the
block's own branch condition (or its inverse). This works remarkably
well considering it doesn't do any deduction on these facts, but it
has various downsides:
1. It requires an implementation both of adding facts to the table and
determining implications. These are very nearly duals of each
other, but require separate implementations. Likewise, the process
of asserting facts of dominating branch conditions is very nearly
the dual of the process of querying implied branch conditions.
2. It leads to less effective use of derived facts. For example, the
prove pass currently derives facts about the relations between len
and cap, but can't make use of these unless a branch condition is
in the exact form of a derived fact. If one of these derived facts
contradicts another fact, it won't notice or make use of this.
This CL changes the approach of the prove pass to instead use
*contradiction* instead of implication. Rather than ever querying a
branch condition, it simply adds branch conditions to the fact table.
If this leads to a contradiction (specifically, it makes the fact set
unsatisfiable), that branch is impossible and can be cut. As a result,
1. We can eliminate the code for determining implications
(factsTable.get disappears entirely). Also, there is now a single
implementation of visiting and asserting branch conditions, since
we don't have to flip them around to treat them as facts in one
place and queries in another.
2. Derived facts can be used effectively. It doesn't matter *why* the
fact table is unsatisfiable; a contradiction in any of the facts is
enough.
3. As an added benefit, it's now quite easy to avoid traversing beyond
provably-unreachable blocks. In contrast, the current
implementation always visits all blocks.
The prove pass already has nearly all of the mechanism necessary to
compute unsatisfiability, which means this both simplifies the code
and makes it more powerful.
The only complication is that the current implication procedure has a
hack for dealing with the 0 <= Args[0] condition of OpIsInBounds and
OpIsSliceInBounds. We replace this with asserting the appropriate fact
when we process one of these conditions. This seems much cleaner
anyway, and works because we can now take advantage of derived facts.
This has no measurable effect on compiler performance.
Effectiveness:
There is exactly one condition in all of std and cmd that this fails
to prove that the old implementation could: (int64(^uint(0)>>1) < x)
in encoding/gob. This can never be true because x is an int, and it's
basically coincidence that the old code gets this. (For example, it
fails to prove the similar (x < ^int64(^uint(0)>>1)) condition that
immediately precedes it, and even though the conditions are logically
unrelated, it wouldn't get the second one if it hadn't first processed
the first!)
It does, however, prove a few dozen additional branches. These come
from facts that are added to the fact table about the relations
between len and cap. These were almost never queried directly before,
but could lead to contradictions, which the unsat-based approach is
able to use.
There are exactly two branches in std and cmd that this implementation
proves in the *other* direction. This sounds scary, but is okay
because both occur in already-unreachable blocks, so it doesn't matter
what we chose. Because the fact table logic is sound but incomplete,
it fails to prove that the block isn't reachable, even though it is
able to prove that both outgoing branches are impossible. We could
turn these blocks into BlockExit blocks, but it doesn't seem worth the
trouble of the extra proof effort for something that happens twice in
all of std and cmd.
Tests:
This CL updates test/prove.go to change the expected messages because
it can no longer give a "reason" why it proved or disproved a
condition. It also adds a new test of a branch it couldn't prove
before.
It mostly guts test/sliceopt.go, removing everything related to slice
bounds optimizations and moving a few relevant tests to test/prove.go.
Much of this test is actually unreachable. The new prove pass figures
this out and doesn't try to prove anything about the unreachable
parts. The output on the unreachable parts is already suspect because
anything can be proved at that point, so it's really just a regression
test for an algorithm the compiler no longer uses.
This is a step toward fixing #23354. That issue is quite easy to fix
once we can use derived facts effectively.
Change-Id: Ia48a1b9ee081310579fe474e4a61857424ff8ce8
Reviewed-on: https://go-review.googlesource.com/87478 Reviewed-by: Keith Randall <khr@golang.org>
Austin Clements [Wed, 10 Jan 2018 22:39:43 +0000 (17:39 -0500)]
cmd/compile: simplify limit logic in prove
This replaces the open-coded intersection of limits in the prove pass
with a general limit intersection operation. This should get identical
results except in one case where it's more precise: when handling an
equality relation, if the value is *outside* the existing range, this
will reduce the range to empty rather than resetting it. This will be
important to a follow-up CL where we can take advantage of empty
ranges.
For #23354.
Change-Id: I3d3d75924f61b1da1cb604b3a9d189b26fb3a14e
Reviewed-on: https://go-review.googlesource.com/87477
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org> Reviewed-by: Alexandru Moșoi <alexandru@mosoi.ro>
Alberto Donizetti [Sun, 14 Jan 2018 18:00:36 +0000 (19:00 +0100)]
math/big: allocate less in Float.Sqrt
The Newton sqrtInverse procedure we use to compute Float.Sqrt should
not allocate a number of times proportional to the number of Newton
iterations we need to reach the desired precision.
At the beginning the function the target precision is known, so even
if we do want to perform the early steps at low precisions (to save
time), it's still possible to pre-allocate larger backing arrays, both
for the temp variables in the loop and the variable that'll hold the
final result.
There's one complication. At the following line:
u.Sub(three, u)
the Sub method will allocate, because the receiver aliases one of the
arguments, and the large backing array we initially allocated for u
will be replaced by a smaller one allocated by Sub. We can work around
this by introducing a second temp variable u2 that we use to hold the
Sub call result.
Overall, the sqrtInverse procedure still allocates a number of times
proportional to the number of Newton steps, because unfortunately a
few of the Mul calls in the Newton function allocate; but at least we
allocate less in the function itself.
Matthew Dempsky [Thu, 8 Mar 2018 09:50:36 +0000 (01:50 -0800)]
cmd/compile: cleanup nodpc and nodfp
Instead of creating a new &nodfp expression for every recover() call,
or a new nodpc variable for every function instrumented by the race
detector, this CL introduces two new uintptr-typed pseudo-variables
callerSP and callerPC. These pseudo-variables act just like calls to
the runtime's getcallersp() and getcallerpc() functions.
For consistency, change runtime.gorecover's builtin stub's parameter
type from "*int32" to "uintptr".
Passes toolstash-check, but toolstash-check -race fails because of
register allocator changes.
Change-Id: I985d644653de2dac8b7b03a28829ad04dfd4f358
Reviewed-on: https://go-review.googlesource.com/99416
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Daniel Martí <mvdan@mvdan.cc> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Michael Kasch [Fri, 2 Mar 2018 18:03:21 +0000 (19:03 +0100)]
time: add support for parsing timezones denoted by sign and offset
IANA Zoneinfo does not provide names for all timezones. Some are denoted
by a sign and an offset only. E.g: Europe/Turkey is currently +03 or
America/La_Paz which is -04 (https://data.iana.org/time-zones/releases/tzdata2018c.tar.gz)
erifan01 [Mon, 16 Oct 2017 10:29:02 +0000 (10:29 +0000)]
math/big: optimize addVW and subVW on arm64
The biggest hot spot of the existing implementation is "load" operations, which lead to poor performance.
By unrolling the cycle 4 times and 2 times, and using "LDP", "STP" instructions,
this CL can reduce the "load" cost and improve performance.
When instructions add, and, or, xor, and movd have
constant operands in some cases more instructions are
generated than necessary by the assembler.
This adds more opcode/operand combinations to the optab
and improves the code generation for the cases where the
size and sign of the constant allows the use of 1
instructions instead of 2.
Example of previous code:
oris r3, r0, 0
ori r3, r3, 65533
now:
ori r3, r0, 65533
This does not significantly reduce the overall binary size
because the improvement depends on the constant value.
Some procedures show a 1-2% reduction in size. This improvement
could also be significant in cases where the extra instructions
occur in a critical loop.
Testcase ppc64enc.s was added to cmd/asm/internal/asm/testdata
with the variations affected by this change.
Joe Tsai [Wed, 7 Mar 2018 22:14:19 +0000 (14:14 -0800)]
encoding/csv: avoid mangling invalid UTF-8 in Writer
In the situation where a quoted field is necessary, avoid processing
each UTF-8 rune one-by-one, which causes mangling of invalid sequences
into utf8.RuneError, causing a loss of information.
Instead, search only for the escaped characters, handle those specially
and copy everything else in between verbatim.
This symmetrically matches the behavior of Reader.
Fixes #24298
Change-Id: I9276f64891084ce8487678f663fad711b4095dbb
Reviewed-on: https://go-review.googlesource.com/99297
Run-TryBot: Joe Tsai <thebrokentoaster@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
The original code inserts "else{", deletes "else", and then positions
a new block just after the "}" that must come before the "else".
That works on gofmt'ed code, but fails if the code looks like "}else".
When there is no space between the "{" and the "else", the new block
is inserted into a location that we are deleting, leading to the
"overlapping edits" mentioned above.
This CL fixes this case by not deleting the "else" but just using the
one that is already there. That requires adjust the block offset to
come after the "{" that we insert.
Fixes #23927
Change-Id: I40ef592490878765bbce6550ddb439e43ac525b2
Reviewed-on: https://go-review.googlesource.com/98935
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Robert Griesemer <gri@golang.org>
Ian Lance Taylor [Mon, 26 Feb 2018 22:03:47 +0000 (14:03 -0800)]
runtime: get traceback from VDSO code
Currently if a profiling signal arrives while executing within a VDSO
the profiler will report _ExternalCode, which is needlessly confusing
for a pure Go program. Change the VDSO calling code to record the
caller's PC/SP, so that we can do a traceback from that point. If that
fails for some reason, report _VDSO rather than _ExternalCode, which
should at least point in the right direction.
This adds some instructions to the code that calls the VDSO, but the
slowdown is reasonably negligible:
Ian Lance Taylor [Wed, 7 Mar 2018 04:47:38 +0000 (20:47 -0800)]
runtime: change from rt_sigaction to sigaction
This normalizes the Linux code to act like other targets. The size
argument to the rt_sigaction system call is pushed to a single
function, sysSigaction.
This is intended as a simplification step for CL 93875 for #14327.
Change-Id: I594788e235f0da20e16e8a028e27ac8c883907c4
Reviewed-on: https://go-review.googlesource.com/99077
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
Elias Naur [Wed, 7 Mar 2018 17:23:21 +0000 (18:23 +0100)]
runtime/cgo: make sure nil is undefined before defining it
While working on standalone builds of gomobile bindings, I ran into
errors on the form:
gcc_darwin_arm.c:30:31: error: ambiguous expansion of macro 'nil' [-Werror,-Wambiguous-macro]
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS11.2.sdk/usr/include/MacTypes.h:94:15: note: expanding this definition of 'nil'
Fix it by undefining nil before defining it in libcgo.h.
Change-Id: I8e9660a68c6c351e592684d03d529f0d182c0493
Reviewed-on: https://go-review.googlesource.com/99215
Run-TryBot: Elias Naur <elias.naur@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Ian Lance Taylor <iant@golang.org>
Matthew Dempsky [Fri, 2 Mar 2018 23:20:49 +0000 (15:20 -0800)]
cmd/compile: prevent untyped types from reaching walk
We already require expressions to have already been typechecked before
reaching walk. Moreover, all untyped expressions should have been
converted to their default type by walk.
However, in practice, we've been somewhat sloppy and inconsistent
about ensuring this. In particular, a lot of AST rewrites ended up
leaving untyped bool expressions scattered around. These likely aren't
harmful in practice, but it seems worth cleaning up.
The two most common cases addressed by this CL are:
1) When generating OIF and OFOR nodes, we would often typecheck the
conditional expression, but not apply defaultlit to force it to the
expression's default type.
2) When rewriting string comparisons into more fundamental primitives,
we were simply overwriting r.Type with the desired type, which didn't
propagate the type to nested subexpressions. These are fixed by
utilizing finishcompare, which correctly handles this (and is already
used by other comparison lowering rewrites).
Lastly, walkexpr is extended to assert that it's not called on untyped
expressions.
Fixes #23834.
Change-Id: Icbd29648a293555e4015d3b06a95a24ccbd3f790
Reviewed-on: https://go-review.googlesource.com/98337 Reviewed-by: Robert Griesemer <gri@golang.org>
1. regexps are matched from the start of the disasm line (excluding
line information). This mean that a negative -"memmove" check will
pass against a 'CALL runtime.memmove' line because the line does
not start with 'memmove' (its starts with CALL...).
The way to specify no 'memmove' match whatsoever on the line is
-".*memmove"
2. AFAIK comments on their own line are matched against the first
subsequent non-comment line. So the code above only verifies that
the x := ... line does not generate a memmove. The comment should
be moved near the copy() line, if it's that one we want to not
generate a memmove call.
The fact that the test above is not effective can be checked by
running `go run run.go -v codegen` in the toplevel test directory with
a go1.10 toolchain (that does not have the memmove-elision
optimization). The test will still pass (it shouldn't).
This change changes the regexp to -".*memmove" and moves it near the
line it needs to (not)match.
Tobias Klauser [Wed, 7 Mar 2018 09:20:19 +0000 (10:20 +0100)]
database/sql: fix typo in comment
Change-Id: Ie2966bae1dc2e542c42fb32d8059a4b2d4690014
Reviewed-on: https://go-review.googlesource.com/99115 Reviewed-by: Ian Lance Taylor <iant@golang.org>