We used to compare the init state with == to 0 and 2, which
requires 2 comparisons. Instead, compare with 1 and use
<, ==. That requires only one comparison.
This isn't a big deal performance-wise, as it is just init
code. But there is a fair amount of init code, so this
should help a bit with code size.
Change-Id: I4a2765f1005776f0edce28ac143f4b7596d95a68
Reviewed-on: https://go-review.googlesource.com/18948
Reviewed-by: David Chase <drchase@google.com>
Rename StoreConst to ValAndOff so we can use it for other ops.
Make ValAndOff print nicely.
Add some notes & checks related to my aborted attempt to
implement combined CMP+load ops.
Change-Id: I2f901d12d42bc5a82879af0334806aa184a97e27
Reviewed-on: https://go-review.googlesource.com/18947
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: David Chase <drchase@google.com>
The old write barriers used _nostore versions, which
don't work for Ian's cgo checker. Instead, we adopt the
same write barrier pattern as the default compiler.
It's a bit trickier to code up but should be more efficient.
Change-Id: I6696c3656cf179e28f800b0e096b7259bd5f3bb7
Reviewed-on: https://go-review.googlesource.com/18941
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Compiling && and || expressions often leads to control
flow of the following form:
p:
If a goto b else c
b: <- p ...
x = phi(a, ...)
If x goto t else u
Note that if we take the edge p->b, then we are guaranteed
to take the edge b->t also. So in this situation, we might
as well go directly from p to t.
Change-Id: I6974f1e6367119a2ddf2014f9741fdb490edcc12
Reviewed-on: https://go-review.googlesource.com/18910
Reviewed-by: David Chase <drchase@google.com>
For each value that needs to be in a fixed register at the end of the
block, and try to pick that fixed register when the instruction
generating that value is scheduled (or restored from a spill).
Just used for end-of-block register requirements for now.
Fixed-register instruction requirements (e.g. shift in ecx) can be
added later. Also two-instruction constraints (input reg == output
reg) might be recorded in a similar manner.
Change-Id: I59916e2e7f73657bb4fc3e3b65389749d7a23fa8
Reviewed-on: https://go-review.googlesource.com/18774
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
The OpSB hack didn't quite work. We need to really
CSE these ops to make regalloc happy.
Change-Id: I9f4d7bfb0929407c84ee60c9e25ff0c0fbea84af
Reviewed-on: https://go-review.googlesource.com/19083
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Some tests make multiple Funcs per Config at once.
With value & block caching, we can't do that any more.
Change-Id: Ibdb60aa2fcf478f1726b3be0fcaa06b04433eb67
Reviewed-on: https://go-review.googlesource.com/19081
Reviewed-by: Keith Randall <khr@golang.org>
It is one of the slowest compiler phases right now, and we
run two of them.
Instead of using a map to make the initial partition, use a sort.
It is much less memory intensive.
Do a few optimizations to avoid work for size-1 equivalence classes.
Implement -N.
Change-Id: I1d2d85d3771abc918db4dd7cc30b0b2d854b15e1
Reviewed-on: https://go-review.googlesource.com/19024
Reviewed-by: David Chase <drchase@google.com>
The x86 backend automatically rewrites MOV $0, AX to
XOR AX, AX. That rewrite isn't ok when the flags register
is live across the MOV. Keep track of which moves care
about preserving flags, then disable this rewrite for them.
On x86, Prog.Mark was being used to hold the length of the
instruction. We already store that in Prog.Isize, so no
need to store it in Prog.Mark also. This frees up Prog.Mark
to hold a bitmask on x86 just like all the other architectures.
Update #12405
Change-Id: Ibad8a8f41fc6222bec1e4904221887d3cc3ca029
Reviewed-on: https://go-review.googlesource.com/18861
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Russ Cox <rsc@golang.org>
The conversion from -0.0 to +0.0 happens inside mpgetflt now.
The SSA code doesn't need this fix any more.
Change-Id: I6cd4f4a4e75b13cf284ebbb95b08af050ed9891c
Reviewed-on: https://go-review.googlesource.com/18942
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
Empty blocks are introduced to remove critical edges.
After regalloc, we can remove any of the added blocks
that are still empty.
Change-Id: I0b40e95ac3a6cc1e632a479443479532b6c5ccd9
Reviewed-on: https://go-review.googlesource.com/18833
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Break small structs up into their components so they
can be registerized.
Change StructSelect to use field indexes instead of
field offsets, as field offsets aren't unique in the
presence of zero-sized fields.
Change-Id: I2f1dc89f7fa58e1cf58aa1a32b238959d53f62e4
Reviewed-on: https://go-review.googlesource.com/18570
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Redo how we keep track of forward references when building SSA.
When the forward reference is resolved, update the Value node
in place.
Improve the phi elimination pass so it can simplify phis of phis.
Give SSA package access to decoded line numbers. Fix line numbers
for constant booleans.
Change-Id: I3dc9896148d260be2f3dd14cbe5db639ec9fa6b7
Reviewed-on: https://go-review.googlesource.com/18674
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
Distinguish move/load/store ops. Unify some of this code a bit.
Reduces Mandelbrot slowdown with SSA from 58% to 12%.
Change-Id: I3276eaebcbcdd9de3f8299c79b5f25c0429194c4
Reviewed-on: https://go-review.googlesource.com/18677
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
If a failure occurs in SSA processing, we always report the
last line of the function we're compiling. Modify the callbacks
from SSA to the GC compiler so we can pass a line number back
and use it in Fatalf.
Change-Id: Ifbfad50d5e167e997e0a96f0775bcc369f5c397e
Reviewed-on: https://go-review.googlesource.com/18599
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: David Chase <drchase@google.com>
The timeout means that TestSpecialDomainName will not hang if
the DNS server does not respond to the request.
Fixes#13939
Change-Id: I46e30bbd3c11b6c560656134e704331cf6f8af3f
Reviewed-on: https://go-review.googlesource.com/18661
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Both mips64 architectures share the same runtime/rt0 file, so
we have to hardcode them in buildall.bash.
Ideally we should have cmd/dist report all supported platforms,
see #12270.
Change-Id: I08ce35cfe0a831af5e1e8255b305efd38386fa52
Reviewed-on: https://go-review.googlesource.com/18687
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
No need to say "by default" because there is no alternative and no way
to override. Always HTTP/2.0 is officially spelled HTTP/2 these days.
Fixes#13985 harder
Change-Id: Ib1ec03cec171ca865342b8e7452cd4c707d7b770
Reviewed-on: https://go-review.googlesource.com/18720
Reviewed-by: Rob Pike <r@golang.org>
Fixes#14001
Change-Id: I6f9bc3028345081758d8f537c3aaddb2e254e69e
Reviewed-on: https://go-review.googlesource.com/18708
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is testing code in asm_GOARCH.s, so it's not necessary to run the
test on systems where it doesn't build.
Fixes#13991.
Change-Id: Ia7a2d3a34b32e6987dc67428c1e09e63baf0518a
Reviewed-on: https://go-review.googlesource.com/18707
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
GC assists check gcBlackenEnabled under the assist queue lock to avoid
going to sleep after gcWakeAllAssists has already woken all assists.
However, currently we clear gcBlackenEnabled shortly *after* waking
all assists, which opens a window where this exact race can happen.
Fix this by clearing gcBlackenEnabled before waking blocked assists.
However, it's unlikely this actually matters because the world is
stopped between waking assists and clearing gcBlackenEnabled and there
aren't any obvious allocations during this window, so I don't think an
assist could actually slip in to this race window.
Updates #13645.
Change-Id: I7571f059530481dc781d8fd96a1a40aadebecb0d
Reviewed-on: https://go-review.googlesource.com/18682
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Also adds missing nosplit to unminit.
Fixes#13964.
Change-Id: I07d93a8c872a255a89f91f808b66c889f0a6a69c
Reviewed-on: https://go-review.googlesource.com/18658
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If a user starts two HTTP requests when no http2 connection is
available, both end up creating new TCP connections, since the
server's protocol (h1 or h2) isn't yet known. Once it turns out that
the server supports h2, one of the connections is useless. Previously
we kept upgrading both TLS connections to h2 (SETTINGS frame exchange,
etc). Now the unnecessary connections are closed instead, before the
h2 preface/SETTINGS.
Updates x/net/http2 to git rev a8e212f3d for https://golang.org/cl/18675
This CL contains the tests for https://golang.org/cl/18675
Semi-related change noticed while writing the tests: now that we have
TLSNextProto in Go 1.6, which consults the TLS
ConnectionState.NegotiatedProtocol, we have to gurantee that the TLS
handshake has been done before we look at the ConnectionState. So add
that check after the DialTLS hook. (we never documented that users
have to call Handshake, so do it for them, now that it matters)
Updates #13957
Change-Id: I9a70e9d1282fe937ea654d9b1269c984c4e366c0
Reviewed-on: https://go-review.googlesource.com/18676
Reviewed-by: Andrew Gerrand <adg@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
While the default behavior of eliding runtime frames from tracebacks
usually makes sense, this is not the case when you're trying to test
the runtime itself. Fix this by forcing the traceback level to at
least "system" in the runtime tests.
This will specifically help with debugging issue #13645, which has
proven remarkably resistant to reproduction outside of the build
dashboard itself.
Change-Id: I2a8356ba6c3c5badba8bb3330fc527357ec0d296
Reviewed-on: https://go-review.googlesource.com/18648
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Passes with go test -race -count=1000 -name=TestServerValidatesHostHeader now
without hanging.
Fixes#13950
Change-Id: I41c3a555c642595c95c8c52f19a05a4c68e67630
Reviewed-on: https://go-review.googlesource.com/18660
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This doesn't fix a bug, but may improve performance in programs that
have many concurrent calls from C to Go. The old code made several
system calls between lockextra and unlockextra. That could be happening
while another thread is spinning acquiring lockextra. This changes the
code to not make any system calls while holding the lock.
Change-Id: I50576478e478670c3d6429ad4e1b7d80f98a19d8
Reviewed-on: https://go-review.googlesource.com/18548
Reviewed-by: Russ Cox <rsc@golang.org>
TestFutexsleep is supposed to clean up before returning by waking up
the goroutines it started and left blocked in futex sleeps. However,
it currently fails at this in several ways:
1. Both the sleep and wakeup are done on the address of tt.mtx, but in
both cases tt is a *local copy* of the futexsleepTest created by a
loop, so the sleep and wakeup happen on completely different
addresses. Fix this by making them both use the address of the
global tt.mtx.
2. If the sleep happens after the wakeup (not likely, but not
impossible), it won't wake up. Fix this by using the futex protocol
properly: sleep if the mutex's value is 0, and set the mutex's
value to non-zero before doing the wakeup.
3. If TestFutexsleep runs more than once, channels and mutex values
left over from the first run will interfere with later runs. Fix
this by clearing the mutex value and creating a new channel for
each test and waiting for goroutines to finish before returning
(lest they send their completion to the channel for the next run).
As an added bonus, this test now actually tests that futex
sleep/wakeup work. Previously this test would have been satisfied if
futexsleep was an infinite loop and futexwakeup was a no-op.
Change-Id: I1cbc6871cc9dcb8f4601b3621913bec2b79b0fc3
Reviewed-on: https://go-review.googlesource.com/18617
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Mikio Hara <mikioh.mikioh@gmail.com>
Otherwise it is impossible to vendor a/b/c without hiding the real a/b.
I also updated golang.org/s/go15vendor.
Fixes#13832.
Change-Id: Iee3d53c11ea870721803f6e8e67845b405686e79
Reviewed-on: https://go-review.googlesource.com/18644
Reviewed-by: Andrew Gerrand <adg@golang.org>
Currently readType simultaneously constructs a type graph and resolves
the sizes of the types. However, these two operations are
fundamentally at odds: the order we parse a cyclic structure in may be
different than the order we need to resolve type sizes in. As a
result, it's possible that when readType attempts to resolve the size
of a typedef, it may dereference a nil Type field of another typedef
retrieved from the type cache that's only partially constructed.
To fix this, we delay resolving typedef sizes until the end of the
readType recursion, when the full type graph is constructed.
Fixes#13039.
Change-Id: I9889af37fb3be5437995030fdd61e45871319d07
Reviewed-on: https://go-review.googlesource.com/18459
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Fixes build on those systems.
Also fix printing of AVARLIVE.
Change-Id: I1b38cca0125689bc08e4e1bdd0d0c140b1ea079a
Reviewed-on: https://go-review.googlesource.com/18641
Reviewed-by: Russ Cox <rsc@golang.org>
This will allow the compiler to crunch Prog lists down to code as each
function is compiled, instead of waiting until the end, which should
reduce the working set of the compiler. But not until Go 1.7.
This also makes it easier to write some machine code output tests
for the assembler, which is why it's being done now.
For #13822.
Change-Id: I0811123bc6e5717cebb8948f9cea18e1b9baf6f7
Reviewed-on: https://go-review.googlesource.com/18311
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Consider this code:
func f(*int)
func g() {
p := new(int)
f(p)
}
where f is an assembly function.
In general liveness analysis assumes that during the call to f, p is dead
in this frame. If f has retained p, p will be found alive in f's frame and keep
the new(int) from being garbage collected. This is all correct and works.
We use the Go func declaration for f to give the assembly function
liveness information (the arguments are assumed live for the entire call).
Now consider this code:
func h1() {
p := new(int)
syscall.Syscall(1, 2, 3, uintptr(unsafe.Pointer(p)))
}
Here syscall.Syscall is taking the place of f, but because its arguments
are uintptr, the liveness analysis and the garbage collector ignore them.
Since p is no longer live in h once the call starts, if the garbage collector
scans the stack while the system call is blocked, it will find no reference
to the new(int) and reclaim it. If the kernel is going to write to *p once
the call finishes, reclaiming the memory is a mistake.
We can't change the arguments or the liveness information for
syscall.Syscall itself, both for compatibility and because sometimes the
arguments really are integers, and the garbage collector will get quite upset
if it finds an integer where it expects a pointer. The problem is that
these arguments are fundamentally untyped.
The solution we have taken in the syscall package's wrappers in past
releases is to insert a call to a dummy function named "use", to make
it look like the argument is live during the call to syscall.Syscall:
func h2() {
p := new(int)
syscall.Syscall(1, 2, 3, uintptr(unsafe.Pointer(p)))
use(unsafe.Pointer(p))
}
Keeping p alive during the call means that if the garbage collector
scans the stack during the system call now, it will find the reference to p.
Unfortunately, this approach is not available to users outside syscall,
because 'use' is unexported, and people also have to realize they need
to use it and do so. There is much existing code using syscall.Syscall
without a 'use'-like function. That code will fail very occasionally in
mysterious ways (see #13372).
This CL fixes all that existing code by making the compiler do the right
thing automatically, without any code modifications. That is, it takes h1
above, which is incorrect code today, and makes it correct code.
Specifically, if the compiler sees a foreign func definition (one
without a body) that has uintptr arguments, it marks those arguments
as "unsafe uintptrs". If it later sees the function being called
with uintptr(unsafe.Pointer(x)) as an argument, it arranges to mark x
as having escaped, and it makes sure to hold x in a live temporary
variable until the call returns, so that the garbage collector cannot
reclaim whatever heap memory x points to.
For now I am leaving the explicit calls to use in package syscall,
but they can be removed early in a future cycle (likely Go 1.7).
The rule has no effect on escape analysis, only on liveness analysis.
Fixes#13372.
Change-Id: I2addb83f70d08db08c64d394f9d06ff0a063c500
Reviewed-on: https://go-review.googlesource.com/18584
Reviewed-by: Ian Lance Taylor <iant@golang.org>
