This commit reworks multiway select statements to use normal control
flow primitives instead of the previous setjmp/longjmp-like behavior.
This simplifies liveness analysis and should prevent issues around
"returns twice" function calls within SSA passes.
test/live.go is updated because liveness analysis's CFG is more
representative of actual control flow. The case bodies are the only
real successors of the selectgo call, but previously the selectsend,
selectrecv, etc. calls were included in the successors list too.
Updates #19331.
Change-Id: I7f879b103a4b85e62fc36a270d812f54c0aa3e83
Reviewed-on: https://go-review.googlesource.com/37661
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Now that we don't rescan stacks, stack barriers are unnecessary. This
removes all of the code and structures supporting them as well as
tests that were specifically for stack barriers.
Updates #17503.
Change-Id: Ia29221730e0f2bbe7beab4fa757f31a032d9690c
Reviewed-on: https://go-review.googlesource.com/36620
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
So it could be inlined.
Using bit-tricks it could be implemented without condition
(improved trick version by Minux Ma).
Simple benchmark shows it is faster on i386 and x86_64, though
I don't know will it be faster on other architectures?
benchmark old ns/op new ns/op delta
BenchmarkFastrand-3 2.79 1.48 -46.95%
BenchmarkFastrandHashiter-3 25.9 24.9 -3.86%
Change-Id: Ie2eb6d0f598c0bb5fac7f6ad0f8b5e3eddaa361b
Reviewed-on: https://go-review.googlesource.com/34782
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On amd64p32, rt0_go attempts to reserve 128 bytes of scratch space on
the stack, but due to a register mixup this ends up being a no-op. Fix
this so we actually reserve the stack space.
Change-Id: I04dbfbeb44f3109528c8ec74e1136bc00d7e1faa
Reviewed-on: https://go-review.googlesource.com/32331
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
gobuf.ctxt is set to nil from many places in assembly code and these
assignments require write barriers with the hybrid barrier.
Conveniently, in most of these places ctxt should already be nil, in
which case we don't need the barrier. This commit changes these places
to assert that ctxt is already nil.
gogo is more complicated, since ctxt may not already be nil. For gogo,
we manually perform the write barrier if ctxt is not nil.
Updates #17503.
Change-Id: I9d75e27c75a1b7f8b715ad112fc5d45ffa856d30
Reviewed-on: https://go-review.googlesource.com/31764
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Since barrier-less memclr is only safe in very narrow circumstances,
this commit renames memclr to avoid accidentally calling memclr on
typed memory. This can cause subtle, non-deterministic bugs, so it's
worth some effort to prevent. In the near term, this will also prevent
bugs creeping in from any concurrent CLs that add calls to memclr; if
this happens, whichever patch hits master second will fail to compile.
This also adds the other new memclr variants to the compiler's
builtin.go to minimize the churn on that binary blob. We'll use these
in future commits.
Updates #17503.
Change-Id: I00eead049f5bd35ca107ea525966831f3d1ed9ca
Reviewed-on: https://go-review.googlesource.com/31369
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Currently reflectcall has a subtle dance with write barriers where the
assembly code copies the result values from the stack to the in-heap
argument frame without write barriers and then calls into the runtime
after the fact to invoke the necessary write barriers.
For the hybrid barrier (and for ROC), we need to switch to a
*pre*-write write barrier, which is very difficult to do with the
current setup. We could tie ourselves in knots of subtle reasoning
about why it's okay in this particular case to have a post-write write
barrier, but this commit instead takes a different approach. Rather
than making things more complex, this simplifies reflection calls so
that the argument copy is done in Go using normal bulk write barriers.
The one difficulty with this approach is that calling into Go requires
putting arguments on the stack, but the call* functions "donate" their
entire stack frame to the called function. We can get away with this
now because the copy avoids using the stack and has copied the results
out before we clobber the stack frame to call into the write barrier.
The solution in this CL is to call another function, passing arguments
in registers instead of on the stack, and let that other function
reserve more stack space and setup the arguments for the runtime.
This approach seemed to work out the best. I also tried making the
call* functions reserve 32 extra bytes of frame for the write barrier
arguments and adjust SP up by 32 bytes around the call. However, even
with the necessary changes to the assembler to correct the spdelta
table, the runtime was still having trouble with the frame layout (and
the changes to the assembler caused many other things that do strange
things with the SP to fail to assemble). The approach I took doesn't
require any funny business with the SP.
Updates #17503.
Change-Id: Ie2bb0084b24d6cff38b5afb218b9e0534ad2119e
Reviewed-on: https://go-review.googlesource.com/31655
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
morestack writes the context pointer to gobuf.ctxt, but since
morestack is written in assembly (and has to be very careful with
state), it does *not* invoke the requisite write barrier for this
write. Instead, we patch this up later, in newstack, where we invoke
an explicit write barrier for ctxt.
This already requires some subtle reasoning, and it's going to get a
lot hairier with the hybrid barrier.
Fix this by simplifying the whole mechanism. Instead of writing
gobuf.ctxt in morestack, just pass the value of the context register
to newstack and let it write it to gobuf.ctxt. This is a normal Go
pointer write, so it gets the normal Go write barrier. No subtle
reasoning required.
Updates #17503.
Change-Id: Ia6bf8459bfefc6828f53682ade32c02412e4db63
Reviewed-on: https://go-review.googlesource.com/31550
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
If morestack runs on the g0 or gsignal stack, it currently performs
some abort operation that typically produces a signal (e.g., it does
an INT $3 on x86). This is useful if you're running in a debugger, but
if you're not, the runtime tries to trap this signal, which is likely
to send the program into a deeper spiral of collapse and lead to very
confusing diagnostic output.
Help out people trying to debug without a debugger by making morestack
print an informative message before blowing up.
Change-Id: I2814c64509b137bfe20a00091d8551d18c2c4749
Reviewed-on: https://go-review.googlesource.com/31133
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This makes it possible to inline getcallersp. getcallersp is on the
hot path of defers, so this slightly speeds up defer:
name old time/op new time/op delta
Defer-4 78.3ns ± 2% 75.1ns ± 1% -4.00% (p=0.000 n=9+8)
Updates #14939.
Change-Id: Icc1cc4cd2f0a81fc4c8344432d0b2e783accacdd
Reviewed-on: https://go-review.googlesource.com/29655
TryBot-Result: Gobot Gobot <gobot@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Found by vet.
Updates #11041
Change-Id: I5217b3e20c6af435d7500d6bb487b9895efe6605
Reviewed-on: https://go-review.googlesource.com/27493
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
They do the same thing, except memequal also has the short-circuit
check if the two pointers are equal.
A) We might as well always do the short-circuit check, it is only 2 instructions.
B) The extra function call (memequal->memeq) is expensive.
benchmark old ns/op new ns/op delta
BenchmarkArrayEqual-8 8.56 5.31 -37.97%
No noticeable affect on the former memeq user (maps).
Fixes#14302
Change-Id: I85d1ada59ed11e64dd6c54667f79d32cc5f81948
Reviewed-on: https://go-review.googlesource.com/19843
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
We need a runtime check because the original issue is encountered
when running cross compiled windows program from linux. It's better
to give a meaningful crash message earlier than to segfault later.
The added test should not impose any measurable overhead to Go
programs.
For #12415.
Change-Id: Ib4a24ef560c09c0585b351d62eefd157b6b7f04c
Reviewed-on: https://go-review.googlesource.com/14207
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
We're allocating TLS storage for m0 anyway, so might as well use it.
Change-Id: I7dc20bbea5320c8ab8a367f18a9540706751e771
Reviewed-on: https://go-review.googlesource.com/16890
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This change breaks out most of the atomics functions in the runtime
into package runtime/internal/atomic. It adds some basic support
in the toolchain for runtime packages, and also modifies linux/arm
atomics to remove the dependency on the runtime's mutex. The mutexes
have been replaced with spinlocks.
all trybots are happy!
In addition to the trybots, I've tested on the darwin/arm64 builder,
on the darwin/arm builder, and on a ppc64le machine.
Change-Id: I6698c8e3cf3834f55ce5824059f44d00dc8e3c2f
Reviewed-on: https://go-review.googlesource.com/14204
Run-TryBot: Michael Matloob <matloob@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Make sure that we're moving or zeroing pointers atomically.
Anything that is a multiple of pointer size and at least
pointer aligned might have pointers in it. All the code looks
ok except for the 1-pointer-sized moves.
Fixes#13160
Update #12552
Change-Id: Ib97d9b918fa9f4cc5c56c67ed90255b7fdfb7b45
Reviewed-on: https://go-review.googlesource.com/16668
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Currently, amd64p32's memmove and memclr use 8 byte writes as much as
possible and 1 byte writes for the tail of the object. However, if an
object ends with a 4 byte pointer at an 8 byte aligned offset, this
may copy/zero the pointer field one byte at a time, allowing the
garbage collector to observe a partially copied pointer.
Fix this by using 4 byte writes instead of 8 byte writes.
Updates #12552.
Change-Id: I13324fd05756fb25ae57e812e836f0a975b5595c
Reviewed-on: https://go-review.googlesource.com/15370
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Currently the runtime can install stack barriers in any frame.
However, the frame of cgocallback_gofunc is special: it's the one
function that switches from a regular G stack to the system stack on
return. Hence, the return PC slot in its frame on the G stack is
actually used to save getg().sched.pc (so tracebacks appear to unwind
to the last Go function running on that G), and not as an actual
return PC for cgocallback_gofunc.
Because of this, if we install a stack barrier in cgocallback_gofunc's
return PC slot, when cgocallback_gofunc does return, it will move the
stack barrier stub PC in to getg().sched.pc and switch back to the
system stack. The rest of the runtime doesn't know how to deal with a
stack barrier stub in sched.pc: nothing knows how to match it up with
the G's stack barrier array and, when the runtime removes stack
barriers, it doesn't know to undo the one in sched.pc. Hence, if the C
code later returns back in to Go code, it will attempt to return
through the stack barrier saved in sched.pc, which may no longer have
correct unwinding information.
Fix this by blacklisting cgocallback_gofunc's frame so the runtime
won't install a stack barrier in it's return PC slot.
Fixes#12238.
Change-Id: I46aa2155df2fd050dd50de3434b62987dc4947b8
Reviewed-on: https://go-review.googlesource.com/13944
Reviewed-by: Russ Cox <rsc@golang.org>
I noticed that they were unimplemented on arm64 but then that they were
in fact not used at all.
Change-Id: Iee579feda2a5e374fa571bcc8c89e4ef607d50f6
Reviewed-on: https://go-review.googlesource.com/13951
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently its possible for the garbage collector to observe
uninitialized memory or stale heap bitmap bits on weakly ordered
architectures such as ARM and PPC. On such architectures, the stores
that zero newly allocated memory and initialize its heap bitmap may
move after a store in user code that makes the allocated object
observable by the garbage collector.
To fix this, add a "publication barrier" (also known as an "export
barrier") before returning from mallocgc. This is a store/store
barrier that ensures any write done by user code that makes the
returned object observable to the garbage collector will be ordered
after the initialization performed by mallocgc. No barrier is
necessary on the reading side because of the data dependency between
loading the pointer and loading the contents of the object.
Fixes one of the issues raised in #9984.
Change-Id: Ia3d96ad9c5fc7f4d342f5e05ec0ceae700cd17c8
Reviewed-on: https://go-review.googlesource.com/11083
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Martin Capitanio <capnm9@gmail.com>
Reviewed-by: Russ Cox <rsc@golang.org>
In preparation for rename of cgocall_errno into cgocall and
asmcgocall_errno into asmcgocall in the fllowinng CL.
rsc requested CL 9387 to be split into two parts. This is first part.
Change-Id: I7434f0e4b44dd37017540695834bfcb1eebf0b2f
Reviewed-on: https://go-review.googlesource.com/11166
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This commit implements stack barriers to minimize the amount of
stack re-scanning that must be done during mark termination.
Currently the GC scans stacks of active goroutines twice during every
GC cycle: once at the beginning during root discovery and once at the
end during mark termination. The second scan happens while the world
is stopped and guarantees that we've seen all of the roots (since
there are no write barriers on writes to local stack
variables). However, this means pause time is proportional to stack
size. In particularly recursive programs, this can drive pause time up
past our 10ms goal (e.g., it takes about 150ms to scan a 50MB heap).
Re-scanning the entire stack is rarely necessary, especially for large
stacks, because usually most of the frames on the stack were not
active between the first and second scans and hence any changes to
these frames (via non-escaping pointers passed down the stack) were
tracked by write barriers.
To efficiently track how far a stack has been unwound since the first
scan (and, hence, how much needs to be re-scanned), this commit
introduces stack barriers. During the first scan, at exponentially
spaced points in each stack, the scan overwrites return PCs with the
PC of the stack barrier function. When "returned" to, the stack
barrier function records how far the stack has unwound and jumps to
the original return PC for that point in the stack. Then the second
scan only needs to proceed as far as the lowest barrier that hasn't
been hit.
For deeply recursive programs, this substantially reduces mark
termination time (and hence pause time). For the goscheme example
linked in issue #10898, prior to this change, mark termination times
were typically between 100 and 500ms; with this change, mark
termination times are typically between 10 and 20ms. As a result of
the reduced stack scanning work, this reduces overall execution time
of the goscheme example by 20%.
Fixes#10898.
The effect of this on programs that are not deeply recursive is
minimal:
name old time/op new time/op delta
BinaryTree17 3.16s ± 2% 3.26s ± 1% +3.31% (p=0.000 n=19+19)
Fannkuch11 2.42s ± 1% 2.48s ± 1% +2.24% (p=0.000 n=17+19)
FmtFprintfEmpty 50.0ns ± 3% 49.8ns ± 1% ~ (p=0.534 n=20+19)
FmtFprintfString 173ns ± 0% 175ns ± 0% +1.49% (p=0.000 n=16+19)
FmtFprintfInt 170ns ± 1% 175ns ± 1% +2.97% (p=0.000 n=20+19)
FmtFprintfIntInt 288ns ± 0% 295ns ± 0% +2.73% (p=0.000 n=16+19)
FmtFprintfPrefixedInt 242ns ± 1% 252ns ± 1% +4.13% (p=0.000 n=18+18)
FmtFprintfFloat 324ns ± 0% 323ns ± 0% -0.36% (p=0.000 n=20+19)
FmtManyArgs 1.14µs ± 0% 1.12µs ± 1% -1.01% (p=0.000 n=18+19)
GobDecode 8.88ms ± 1% 8.87ms ± 0% ~ (p=0.480 n=19+18)
GobEncode 6.80ms ± 1% 6.85ms ± 0% +0.82% (p=0.000 n=20+18)
Gzip 363ms ± 1% 363ms ± 1% ~ (p=0.077 n=18+20)
Gunzip 90.6ms ± 0% 90.0ms ± 1% -0.71% (p=0.000 n=17+18)
HTTPClientServer 51.5µs ± 1% 50.8µs ± 1% -1.32% (p=0.000 n=18+18)
JSONEncode 17.0ms ± 0% 17.1ms ± 0% +0.40% (p=0.000 n=18+17)
JSONDecode 61.8ms ± 0% 63.8ms ± 1% +3.11% (p=0.000 n=18+17)
Mandelbrot200 3.84ms ± 0% 3.84ms ± 1% ~ (p=0.583 n=19+19)
GoParse 3.71ms ± 1% 3.72ms ± 1% ~ (p=0.159 n=18+19)
RegexpMatchEasy0_32 100ns ± 0% 100ns ± 1% -0.19% (p=0.033 n=17+19)
RegexpMatchEasy0_1K 342ns ± 1% 331ns ± 0% -3.41% (p=0.000 n=19+19)
RegexpMatchEasy1_32 82.5ns ± 0% 81.7ns ± 0% -0.98% (p=0.000 n=18+18)
RegexpMatchEasy1_1K 505ns ± 0% 494ns ± 1% -2.16% (p=0.000 n=18+18)
RegexpMatchMedium_32 137ns ± 1% 137ns ± 1% -0.24% (p=0.048 n=20+18)
RegexpMatchMedium_1K 41.6µs ± 0% 41.3µs ± 1% -0.57% (p=0.004 n=18+20)
RegexpMatchHard_32 2.11µs ± 0% 2.11µs ± 1% +0.20% (p=0.037 n=17+19)
RegexpMatchHard_1K 63.9µs ± 2% 63.3µs ± 0% -0.99% (p=0.000 n=20+17)
Revcomp 560ms ± 1% 522ms ± 0% -6.87% (p=0.000 n=18+16)
Template 75.0ms ± 0% 75.1ms ± 1% +0.18% (p=0.013 n=18+19)
TimeParse 358ns ± 1% 364ns ± 0% +1.74% (p=0.000 n=20+15)
TimeFormat 360ns ± 0% 372ns ± 0% +3.55% (p=0.000 n=20+18)
Change-Id: If8a9bfae6c128d15a4f405e02bcfa50129df82a2
Reviewed-on: https://go-review.googlesource.com/10314
Reviewed-by: Russ Cox <rsc@golang.org>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The motivation is that sysAlloc/Free() currently aren't safe to be
called without a valid G, because arm's xadd64() uses locks that require
a valid G.
The solution here was proposed by Dmitry Vyukov: use xadduintptr()
instead of xadd64(), until arm can support xadd64 on all of its
architectures (not a trivial task for arm).
Change-Id: I250252079357ea2e4360e1235958b1c22051498f
Reviewed-on: https://go-review.googlesource.com/9002
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
runtime·main·f is normalized by the linker to runtime.main.f, as is
the compiler-generated symbol runtime.main·f. Change the former to
runtime·mainPC instead.
Fixes issue #9934
Change-Id: I656a6fa6422d45385fa2cc55bd036c6affa1abfe
Reviewed-on: https://go-review.googlesource.com/8234
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Implement runtime.atomicand8 for amd64p32 which was overlooked
in CL 7861.
Change-Id: Ic7eccddc6fd6c4682cac1761294893928f5428a2
Reviewed-on: https://go-review.googlesource.com/7920
Reviewed-by: Minux Ma <minux@golang.org>
Also fixed a stack corruption bug for nacl/amd64p32.
Change-Id: I64b821b16999c296a159137d971af3870053c621
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/7073
Reviewed-by: Dave Cheney <dave@cheney.net>
We used to not call traceback from goexit1.
But now tracer does it and crashes on amd64p32:
runtime: unexpected return pc for runtime.getg called from 0x108a4240
goroutine 18 [runnable, locked to thread]:
runtime.traceGoEnd()
src/runtime/trace.go:758 fp=0x10818fe0 sp=0x10818fdc
runtime.goexit1()
src/runtime/proc1.go:1540 +0x20 fp=0x10818fe8 sp=0x10818fe0
runtime.getg(0x0)
src/runtime/asm_386.s:2414 fp=0x10818fec sp=0x10818fe8
created by runtime/pprof_test.TestTraceStress
src/runtime/pprof/trace_test.go:123 +0x500
Return PC from goexit1 points right after goexit (+0x6).
It happens to work most of the time somehow.
This change fixes traceback from goexit1 by adding an additional NOP to goexit.
Fixes#9931
Change-Id: Ied25240a181b0a2d7bc98127b3ed9068e9a1a13e
Reviewed-on: https://go-review.googlesource.com/5460
Reviewed-by: Russ Cox <rsc@golang.org>
Package runtime's Go code was converted to directly call getcallerpc
and getcallersp in https://golang.org/cl/138740043, but the assembly
implementations were not removed.
Change-Id: Ib2eaee674d594cbbe799925aae648af782a01c83
Reviewed-on: https://go-review.googlesource.com/5901
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
eqstring does not need to check the length of the strings.
6g
benchmark old ns/op new ns/op delta
BenchmarkCompareStringEqual 7.03 6.14 -12.66%
BenchmarkCompareStringIdentical 3.36 3.04 -9.52%
5g
benchmark old ns/op new ns/op delta
BenchmarkCompareStringEqual 238 232 -2.52%
BenchmarkCompareStringIdentical 90.8 80.7 -11.12%
The equivalent PPC changes are in a separate commit
because I don't have the hardware to test them.
Change-Id: I292874324b9bbd9d24f57a390cfff8b550cdd53c
Reviewed-on: https://go-review.googlesource.com/3955
Reviewed-by: Keith Randall <khr@golang.org>
The function is here ONLY for symmetry with package bytes.
This function should be used ONLY if it makes code clearer.
It is not here for performance. Remove any performance benefit.
If performance becomes an issue, the compiler should be fixed to
recognize the three-way compare (for all comparable types)
rather than encourage people to micro-optimize by using this function.
Change-Id: I71f4130bce853f7aef724c6044d15def7987b457
Reviewed-on: https://go-review.googlesource.com/3012
Reviewed-by: Rob Pike <r@golang.org>
The implementation is the same assembly (or Go) routine.
Change-Id: Ib937c461c24ad2d5be9b692b4eed40d9eb031412
Reviewed-on: https://go-review.googlesource.com/2828
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Also fix one unaligned stack size for nacl that is caught
by this change.
Fixes#9539.
Change-Id: Ib696a573d3f1f9bac7724f3a719aab65a11e04d3
Reviewed-on: https://go-review.googlesource.com/2600
Reviewed-by: Keith Randall <khr@golang.org>
The equal algorithm used to take the size
equal(p, q *T, size uintptr) bool
With this change, it does not
equal(p, q *T) bool
Similarly for the hash algorithm.
The size is rarely used, as most equal functions know the size
of the thing they are comparing. For instance f32equal already
knows its inputs are 4 bytes in size.
For cases where the size is not known, we allocate a closure
(one for each size needed) that points to an assembly stub that
reads the size out of the closure and calls generic code that
has a size argument.
Reduces the size of the go binary by 0.07%. Performance impact
is not measurable.
Change-Id: I6e00adf3dde7ad2974adbcff0ee91e86d2194fec
Reviewed-on: https://go-review.googlesource.com/2392
Reviewed-by: Russ Cox <rsc@golang.org>
Use typedmemmove, typedslicecopy, and adjust reflect.call
to execute the necessary write barriers.
Found with GODEBUG=wbshadow=2 mode.
Eventually that will run automatically, but right now
it still detects other missing write barriers.
Change-Id: Iec5b5b0c1be5589295e28e5228e37f1a92e07742
Reviewed-on: https://go-review.googlesource.com/2312
Reviewed-by: Keith Randall <khr@golang.org>
This reverts commit ab0535ae3f.
I think it will remain useful to distinguish code that must
run on a system stack from code that can run on either stack,
even if that distinction is no
longer based on the implementation language.
That is, I expect to add a //go:systemstack comment that,
in terms of the old implementation, tells the compiler,
to pretend this function was written in C.
Change-Id: I33d2ebb2f99ae12496484c6ec8ed07233d693275
Reviewed-on: https://go-review.googlesource.com/2275
Reviewed-by: Russ Cox <rsc@golang.org>
Now that we've removed all the C code in runtime and the C compilers,
there is no need to have a separate stackguard field to check for C
code on Go stack.
Remove field g.stackguard1 and rename g.stackguard0 to g.stackguard.
Adjust liblink and cmd/ld as necessary.
Change-Id: I54e75db5a93d783e86af5ff1a6cd497d669d8d33
Reviewed-on: https://go-review.googlesource.com/2144
Reviewed-by: Keith Randall <khr@golang.org>
Replace with uses of //go:linkname in Go files, direct use of name in .s files.
The only one that really truly needs a jump is reflect.call; the jump is now
next to the runtime.reflectcall assembly implementations.
Change-Id: Ie7ff3020a8f60a8e4c8645fe236e7883a3f23f46
Reviewed-on: https://go-review.googlesource.com/1962
Reviewed-by: Austin Clements <austin@google.com>
We don't know what we need yet, so add them all.
Add them even on x86 architectures (as no-ops) so that
the GC can refer to them unconditionally.
Eventually we'll know what we want and probably
have just one 'prefetch' with an appropriate meaning
on each architecture.
LGTM=rlh
R=rlh
CC=golang-codereviews
https://golang.org/cl/179160043
This is to reduce the delta between dev.cc and dev.garbage to just garbage collector changes.
These are the files that had merge conflicts and have been edited by hand:
malloc.go
mem_linux.go
mgc.go
os1_linux.go
proc1.go
panic1.go
runtime1.go
LGTM=austin
R=austin
CC=golang-codereviews
https://golang.org/cl/174180043
Scalararg and ptrarg are not "signal safe".
Go code filling them out can be interrupted by a signal,
and then the signal handler runs, and if it also ends up
in Go code that uses scalararg or ptrarg, now the old
values have been smashed.
For the pieces of code that do need to run in a signal handler,
we introduced onM_signalok, which is really just onM
except that the _signalok is meant to convey that the caller
asserts that scalarg and ptrarg will be restored to their old
values after the call (instead of the usual behavior, zeroing them).
Scalararg and ptrarg are also untyped and therefore error-prone.
Go code can always pass a closure instead of using scalararg
and ptrarg; they were only really necessary for C code.
And there's no more C code.
For all these reasons, delete scalararg and ptrarg, converting
the few remaining references to use closures.
Once those are gone, there is no need for a distinction between
onM and onM_signalok, so replace both with a single function
equivalent to the current onM_signalok (that is, it can be called
on any of the curg, g0, and gsignal stacks).
The name onM and the phrase 'm stack' are misnomers,
because on most system an M has two system stacks:
the main thread stack and the signal handling stack.
Correct the misnomer by naming the replacement function systemstack.
Fix a few references to "M stack" in code.
The main motivation for this change is to eliminate scalararg/ptrarg.
Rick and I have already seen them cause problems because
the calling sequence m.ptrarg[0] = p is a heap pointer assignment,
so it gets a write barrier. The write barrier also uses onM, so it has
all the same problems as if it were being invoked by a signal handler.
We worked around this by saving and restoring the old values
and by calling onM_signalok, but there's no point in keeping this nice
home for bugs around any longer.
This CL also changes funcline to return the file name as a result
instead of filling in a passed-in *string. (The *string signature is
left over from when the code was written in and called from C.)
That's arguably an unrelated change, except that once I had done
the ptrarg/scalararg/onM cleanup I started getting false positives
about the *string argument escaping (not allowed in package runtime).
The compiler is wrong, but the easiest fix is to write the code like
Go code instead of like C code. I am a bit worried that the compiler
is wrong because of some use of uninitialized memory in the escape
analysis. If that's the reason, it will go away when we convert the
compiler to Go. (And if not, we'll debug it the next time.)
LGTM=khr
R=r, khr
CC=austin, golang-codereviews, iant, rlh
https://golang.org/cl/174950043
The main change is that #include "zasm_GOOS_GOARCH.h"
is now #include "go_asm.h" and/or #include "go_tls.h".
Also, because C StackGuard is now Go _StackGuard,
the assembly name changes from const_StackGuard to
const__StackGuard.
In asm_$GOARCH.s, add new function getg, formerly
implemented in C.
The renamed atomics now have Go wrappers, to get
escape analysis annotations right. Those wrappers
are in CL 174860043.
LGTM=r, aram
R=r, aram
CC=austin, dvyukov, golang-codereviews, iant, khr
https://golang.org/cl/168510043
