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Previously, the write barrier calls themselves did the actual
writes to memory. Instead, move those writes out to a common location
that both the wb-enabled and wb-disabled code paths share.
This enables us to optimize the write barrier path without having
to worry about performing the actual writes.
Change-Id: Ia71ab651908ec124cc33141afb52e4ca19733ac6
Reviewed-on: https://go-review.googlesource.com/c/go/+/447780
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Bypass: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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Future CLs will remove the invariant that pointers are always put in
the write barrier in pairs.
The behavior of the assembly code changes a bit, where instead of writing
the pointers unconditionally and then checking for overflow, check for
overflow first and then write the pointers.
Also changed the write barrier flush function to not take the src/dst
as arguments.
Change-Id: I2ef708038367b7b82ea67cbaf505a1d5904c775c
Reviewed-on: https://go-review.googlesource.com/c/go/+/447779
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Bypass: Keith Randall <khr@golang.org>
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On LR architectures, morestack (and morestack_noctxt) are called
with a special calling convention, where the caller doesn't save
LR on stack but passes it as a register, which morestack will save
to g.sched.lr. The stack unwinder currently doesn't understand it,
and would fail to unwind from it. morestack already writes SP (as
it switches stack), but morestack_noctxt (which tailcalls
morestack) doesn't. If a profiling signal lands right in
morestack_noctxt, the unwinder will try to unwind the stack and
go off, and possibly crash.
Marking morestack_noctxt SPWRITE stops the unwinding.
Ideally we could teach the unwinder about the special calling
convention, or change the calling convention to be less special
(so the unwinder doesn't need to fetch a register from the signal
context). This is a stop-gap solution, to stop the unwinder from
crashing.
Fixes #54332.
Change-Id: I75295f2e27ddcf05f1ea0b541aedcb9000ae7576
Reviewed-on: https://go-review.googlesource.com/c/go/+/425396
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
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CL 344955 and CL 359476 removed almost all // +build lines, but leaving
some assembly files and generating scripts. Also, some files were added
with // +build lines after CL 359476 was merged. Remove these or rename
files where more appropriate.
For #41184
Change-Id: I7eb85a498ed9788b42a636e775f261d755504ffa
Reviewed-on: https://go-review.googlesource.com/c/go/+/361480
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
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In asmcgocall() we need to switch to the g0 stack if we're not already on
the g0 stack or the gsignal stack. The prefered way of doing this is to
check gsignal first, then g0, since if we are going to switch to g0 we will
need g0 handy (thus avoiding a second load).
Rewrite/reorder 386 and amd64 to check gsignal first - this shaves a few
assembly instructions off and makes the order consistent with arm, arm64,
mips64 and ppc64. Add missing gsignal checks to mips, riscv64 and s390x.
Change-Id: I1b027bf393c25e0c33e1d8eb80de67e4a0a3f561
Reviewed-on: https://go-review.googlesource.com/c/go/+/335869
Trust: Joel Sing <joel@sing.id.au>
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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Currently, deferreturn runs deferred functions by backing up its
return PC to the deferreturn call, and then effectively tail-calling
the deferred function (via jmpdefer). The effect of this is that the
deferred function appears to be called directly from the deferee, and
when it returns, the deferee calls deferreturn again so it can run the
next deferred function if necessary.
This unusual flow control leads to a large number of special cases and
complications all over the tool chain.
This used to be necessary because deferreturn copied the deferred
function's argument frame directly into its caller's frame and then
had to invoke that call as if it had been called from its caller's
frame so it could access it arguments. But now that we've simplified
defer processing so the runtime only deals with argument-less
closures, this approach is no longer necessary.
This CL simplifies all of this by making deferreturn simply call
deferred functions in a loop.
This eliminates the need for jmpdefer, so we can delete a bunch of
per-architecture assembly code.
This eliminates several special cases on Wasm, since it couldn't
support these calling shenanigans directly and thus had to simulate
the loop a different way. Now Wasm can largely work the way the other
platforms do.
This eliminates the per-architecture Ginsnopdefer operation. On PPC64,
this was necessary to reload the TOC pointer after the tail call
(since TOC pointers in general make tail calls impossible). The tail
call is gone, and in the case where we do force a jump to the
deferreturn call when recovering from an open-coded defer, we go
through gogo (via runtime.recovery), which handles the TOC. On other
platforms, we needed a NOP so traceback didn't get confused by seeing
the return to the CALL instruction, rather than the usual return to
the instruction following the CALL instruction. Now we don't inject a
return to the CALL instruction at all, so this NOP is also
unnecessary.
The one potential effect of this is that deferreturn could now appear
in stack traces from deferred functions. However, this could already
happen from open-coded defers, so we've long since marked deferreturn
as a "wrapper" so it gets elided not only from printed stack traces,
but from runtime.Callers*.
This is a retry of CL 337652 because we had to back out its parent.
There are no changes in this version.
Change-Id: I3f54b7fec1d7ccac71cc6cf6835c6a46b7e5fb6c
Reviewed-on: https://go-review.googlesource.com/c/go/+/339397
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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replace jmpdefer with a loop"
This reverts CL 227652.
I'm reverting CL 337651 and this builds on top of it.
Change-Id: I03ce363be44c2a3defff2e43e7b1aad83386820d
Reviewed-on: https://go-review.googlesource.com/c/go/+/338709
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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Currently, deferreturn runs deferred functions by backing up its
return PC to the deferreturn call, and then effectively tail-calling
the deferred function (via jmpdefer). The effect of this is that the
deferred function appears to be called directly from the deferee, and
when it returns, the deferee calls deferreturn again so it can run the
next deferred function if necessary.
This unusual flow control leads to a large number of special cases and
complications all over the tool chain.
This used to be necessary because deferreturn copied the deferred
function's argument frame directly into its caller's frame and then
had to invoke that call as if it had been called from its caller's
frame so it could access it arguments. But now that we've simplified
defer processing so the runtime only deals with argument-less
closures, this approach is no longer necessary.
This CL simplifies all of this by making deferreturn simply call
deferred functions in a loop.
This eliminates the need for jmpdefer, so we can delete a bunch of
per-architecture assembly code.
This eliminates several special cases on Wasm, since it couldn't
support these calling shenanigans directly and thus had to simulate
the loop a different way. Now Wasm can largely work the way the other
platforms do.
This eliminates the per-architecture Ginsnopdefer operation. On PPC64,
this was necessary to reload the TOC pointer after the tail call
(since TOC pointers in general make tail calls impossible). The tail
call is gone, and in the case where we do force a jump to the
deferreturn call when recovering from an open-coded defer, we go
through gogo (via runtime.recovery), which handles the TOC. On other
platforms, we needed a NOP so traceback didn't get confused by seeing
the return to the CALL instruction, rather than the usual return to
the instruction following the CALL instruction. Now we don't inject a
return to the CALL instruction at all, so this NOP is also
unnecessary.
The one potential effect of this is that deferreturn could now appear
in stack traces from deferred functions. However, this could already
happen from open-coded defers, so we've long since marked deferreturn
as a "wrapper" so it gets elided not only from printed stack traces,
but from runtime.Callers*.
Change-Id: Ie9f700cd3fb774f498c9edce363772a868407bf7
Reviewed-on: https://go-review.googlesource.com/c/go/+/337652
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
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newproc/deferproc
newproc/deferproc takes a siz argument for the go'd/deferred
function's argument size. Now it is always zero. Remove the
argument.
Change-Id: If1bb8d427e34015ccec0ba10dbccaae96757fa8c
Reviewed-on: https://go-review.googlesource.com/c/go/+/325917
Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
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Don't add them to files in vendor and cmd/vendor though. These will be
pulled in by updating the respective dependencies.
For #41184
Change-Id: Icc57458c9b3033c347124323f33084c85b224c70
Reviewed-on: https://go-review.googlesource.com/c/go/+/319389
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
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Panic if the slice is too short.
Updates #395
Change-Id: I90f4bff2da5d8f3148ba06d2482084f32b25c29a
Reviewed-on: https://go-review.googlesource.com/c/go/+/301650
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
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The regabi builders are unhappy about badctxt calling throw
calling systemstack calling gosave_systemstack_switch calling
badctxt, all nosplit, repeating. This wouldn't actually happen
since after one systemstack we'd end up on the system stack
and the next one wouldn't call gosave_systemstack_switch at all.
The badctxt call itself is in a very unlikely assertion failure
inside gosave_systemstack_switch.
Keep the assertion check but call runtime.abort instead on failure,
breaking the detected (but not real) cycle.
Change-Id: Iaf5c0fc065783b8c1c6d0f62d848f023a0714b96
Reviewed-on: https://go-review.googlesource.com/c/go/+/294069
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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No change to actual runtime, but helps reduce the laundry list
of functions.
mcall, morestack, and asmcgocall are not actually top-of-frame,
so those need more attention in follow-up CLs.
mstart moved to assembly so that it can be marked TOPFRAME.
Since TOPFRAME also tells DWARF consumers not to unwind
this way, this change should also improve debuggers a
marginal amount.
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: If1e0d46ca973de5e46b62948d076f675f285b5d9
Reviewed-on: https://go-review.googlesource.com/c/go/+/288802
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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A g's sched.g is set in newproc1:
newg.sched.g = guintptr(unsafe.Pointer(newg))
After that, it never changes. Yet lots of assembly code does
"g.sched.g = g" unnecessarily. Remove all those lines to avoid
confusion about whether it ever changes.
Also, split gogo into two functions, one that does the nil g check
and a second that does the actual switch. This way, if the nil g check
fails, we get a stack trace showing the call stack that led to the failure.
(The SP write would otherwise cause the stack trace to abort.)
Also restore the proper nil g check in a handful of assembly functions.
(There is little point in checking for nil g *after* installing it as the real g.)
Change-Id: I22866b093f901f765de1d074e36eeec10366abfb
Reviewed-on: https://go-review.googlesource.com/c/go/+/292109
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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Both asmcgocall and systemstack need to save the calling Go code's
context for use by traceback, but they do it differently.
Systemstack's appraoch is better, because it doesn't require a
special case in traceback.
So make them both use that.
While we are here, the fake mstart caller in systemstack is
no longer needed and can be removed.
(traceback knows to stop in systemstack because of the writes to SP.)
Also remove the fake mstarts in sys_windows_*.s.
And while we are there, fix the control flow guard code in sys_windows_arm.s.
The current code is using pointers to a stack frame that technically is gone
once we hit the RET instruction. Clearly it's working OK, but better not to depend
on data below SP being preserved, even for just a few instructions.
Store the value we need in other registers instead.
(This code is only used for pushing a sigpanic call, which does not
actually return to the site of the fault and therefore doesn't need to
preserve any of the registers.)
This CL is part of a stack adding windows/arm64
support (#36439), intended to land in the Go 1.17 cycle.
This CL is, however, not windows/arm64-specific.
It is cleanup meant to make the port (and future ports) easier.
Change-Id: Id1e3ef5e54f7ad786e4b87043f2626eba7c3bbd9
Reviewed-on: https://go-review.googlesource.com/c/go/+/288799
Trust: Russ Cox <rsc@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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This change adds support for the new register ABI on amd64 to
reflect.(Value).Call. If internal/abi's register counts are non-zero,
reflect will try to set up arguments in registers on the Call path.
Note that because the register ABI becomes ABI0 with zero registers
available, this should keep working as it did before.
This change does not add any tests for the register ABI case because
there's no way to do so at the moment.
For #40724.
Change-Id: I8aa089a5aa5a31b72e56b3d9388dd3f82203985b
Reviewed-on: https://go-review.googlesource.com/c/go/+/272568
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
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The runtime.gosave function is not used anywhere. Delete.
Note: there is also a gosave<> function, which is actually used
and not deleted.
Change-Id: I64149a7afdd217de26d1e6396233f2becfad7153
Reviewed-on: https://go-review.googlesource.com/c/go/+/289719
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
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This redesigns the way calls work from C to exported Go functions. It
removes several steps from the call path, makes cmd/cgo no longer
sensitive to the Go calling convention, and eliminates the use of
reflectcall from cgo.
In order to avoid generating a large amount of FFI glue between the C
and Go ABIs, the cgo tool has long depended on generating a C function
that marshals the arguments into a struct, and then the actual ABI
switch happens in functions with fixed signatures that simply take a
pointer to this struct. In a way, this CL simply pushes this idea
further.
Currently, the cgo tool generates this argument struct in the exact
layout of the Go stack frame and depends on reflectcall to unpack it
into the appropriate Go call (even though it's actually
reflectcall'ing a function generated by cgo).
In this CL, we decouple this struct from the Go stack layout. Instead,
cgo generates a Go function that takes the struct, unpacks it, and
calls the exported function. Since this generated function has a
generic signature (like the rest of the call path), we don't need
reflectcall and can instead depend on the Go compiler itself to
implement the call to the exported Go function.
One complication is that syscall.NewCallback on Windows, which
converts a Go function into a C function pointer, depends on
cgocallback's current dynamic calling approach since the signatures of
the callbacks aren't known statically. For this specific case, we
continue to depend on reflectcall. Really, the current approach makes
some overly simplistic assumptions about translating the C ABI to the
Go ABI. Now we're at least in a much better position to do a proper
ABI translation.
For comparison, the current cgo call path looks like:
GoF (generated C function) ->
crosscall2 (in cgo/asm_*.s) ->
_cgoexp_GoF (generated Go function) ->
cgocallback (in asm_*.s) ->
cgocallback_gofunc (in asm_*.s) ->
cgocallbackg (in cgocall.go) ->
cgocallbackg1 (in cgocall.go) ->
reflectcall (in asm_*.s) ->
_cgoexpwrap_GoF (generated Go function) ->
p.GoF
Now the call path looks like:
GoF (generated C function) ->
crosscall2 (in cgo/asm_*.s) ->
cgocallback (in asm_*.s) ->
cgocallbackg (in cgocall.go) ->
cgocallbackg1 (in cgocall.go) ->
_cgoexp_GoF (generated Go function) ->
p.GoF
Notably:
1. We combine _cgoexp_GoF and _cgoexpwrap_GoF and move the combined
operation to the end of the sequence. This combined function also
handles reflectcall's previous role.
2. We combined cgocallback and cgocallback_gofunc since the only
purpose of having both was to convert a raw PC into a Go function
value. We instead construct the Go function value in cgocallbackg1.
3. cgocallbackg1 no longer reaches backwards through the stack to get
the arguments to cgocallback_gofunc. Instead, we just pass the
arguments down.
4. Currently, we need an explicit msanwrite to mark the results struct
as written because reflectcall doesn't do this. Now, the results are
written by regular Go assignments, so the Go compiler generates the
necessary MSAN annotations. This also means we no longer need to track
the size of the arguments frame.
Updates #40724, since now we don't need to teach cgo about the
register ABI or change how it uses reflectcall.
Change-Id: I7840489a2597962aeb670e0c1798a16a7359c94f
Reviewed-on: https://go-review.googlesource.com/c/go/+/258938
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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Currently the standard hasher is memhash, which checks whether aes
instructions are available, and if so redirects to aeshash.
With this CL, we call aeshash directly, which then redirects to the
fallback hash if aes instructions are not available.
This reduces the overhead for the hash function in the common case,
as it requires just one call instead of two. On architectures which
have no assembly hasher, it's a single jump slower.
Thanks to Martin for this idea.
name old time/op new time/op delta
BigKeyMap-4 22.6ns ± 1% 21.1ns ± 2% -6.55% (p=0.000 n=9+10)
Change-Id: Ib7ca77b63d28222eb0189bc3d7130531949d853c
Reviewed-on: https://go-review.googlesource.com/c/go/+/190998
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
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This CL adds a new attribute, TOPFRAME, which can be used to mark
functions that should be treated as being at the top of the call
stack. The function `runtime.goexit` has been marked this way on
architectures that use a link register.
This will stop programs that use DWARF to unwind the call stack
from unwinding past `runtime.goexit` on architectures that use a
link register. For example, it eliminates "corrupt stack?"
warnings when generating a backtrace that hits `runtime.goexit`
in GDB on s390x.
Similar code should be added for non-link-register architectures
(i.e. amd64, 386). They mark the top of the call stack slightly
differently to link register architectures so I haven't added
that code (they need to mark "rip" as undefined).
Fixes #24385.
Change-Id: I15b4c69ac75b491daa0acf0d981cb80eb06488de
Reviewed-on: https://go-review.googlesource.com/c/go/+/169726
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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A few examples (for accessing a slice of length 3):
s[-1] runtime error: index out of range [-1]
s[3] runtime error: index out of range [3] with length 3
s[-1:0] runtime error: slice bounds out of range [-1:]
s[3:0] runtime error: slice bounds out of range [3:0]
s[3:-1] runtime error: slice bounds out of range [:-1]
s[3:4] runtime error: slice bounds out of range [:4] with capacity 3
s[0:3:4] runtime error: slice bounds out of range [::4] with capacity 3
Note that in cases where there are multiple things wrong with the
indexes (e.g. s[3:-1]), we report one of those errors kind of
arbitrarily, currently the rightmost one.
An exhaustive set of examples is in issue30116[u].out in the CL.
The message text has the same prefix as the old message text. That
leads to slightly awkward phrasing but hopefully minimizes the chance
that code depending on the error text will break.
Increases the size of the go binary by 0.5% (amd64). The panic functions
take arguments in registers in order to keep the size of the compiled code
as small as possible.
Fixes #30116
Change-Id: Idb99a827b7888822ca34c240eca87b7e44a04fdd
Reviewed-on: https://go-review.googlesource.com/c/go/+/161477
Run-TryBot: Keith Randall <khr@golang.org>
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Reviewed-by: David Chase <drchase@google.com>
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Currently, package runtime contains the definition of reflect.call,
even though it's just a jump to runtime.reflectcall. This "push"
symbol is confusing, since it's not clear where the definition of
reflect.call comes from when you're in the reflect package.
Replace this with a "pull" symbol: the runtime now defines only
runtime.reflectcall and package reflect uses a go:linkname to access
this symbol directly. This makes it clear where reflect.call is coming
from without any spooky action at a distance and eliminates all of the
definitions of reflect.call in the runtime.
Change-Id: I3ec73cd394efe9df8d3061a57c73aece2e7048dd
Reviewed-on: https://go-review.googlesource.com/c/148657
Run-TryBot: Austin Clements <austin@google.com>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
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Add a compiler intrinsic for getcallerpc on following architectures:
arm
mips mipsle mips64 mips64le
ppc64 ppc64le
s390x
Change-Id: I758f3d4742fc214b206bcd07d90408622c17dbef
Reviewed-on: https://go-review.googlesource.com/110835
Run-TryBot: Wei Xiao <Wei.Xiao@arm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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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.
Change-Id: Ic5b4a610df265e47962dcfa341cabac03c31c049
Reviewed-on: https://go-review.googlesource.com/93659
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
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Move bytes.Compare and runtime·cmpstring to bytealg.
Update #19792
Change-Id: I139e6d7c59686bef7a3017e3dec99eba5fd10447
Reviewed-on: https://go-review.googlesource.com/98515
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
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Move bytes.Equal, runtime.memequal, and runtime.memequal_varlen
to the bytealg package.
Update #19792
Change-Id: Ic4175e952936016ea0bda6c7c3dbb33afdc8e4ac
Reviewed-on: https://go-review.googlesource.com/98355
Run-TryBot: Keith Randall <khr@golang.org>
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Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
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Move the IndexByte function from the runtime to a new bytealg package.
The new package will eventually hold all the optimized assembly for
groveling through byte slices and strings. It seems a better home for
this code than randomly keeping it in runtime.
Once this is in, the next step is to move the other functions
(Compare, Equal, ...).
Update #19792
This change seems complicated enough that we might just declare
"not worth it" and abandon. Opinions welcome.
The core assembly is all unchanged, except minor modifications where
the code reads cpu feature bits.
The wrapper functions have been cleaned up as they are now actually
checked by vet.
Change-Id: I9fa75bee5d85db3a65b3fd3b7997e60367523796
Reviewed-on: https://go-review.googlesource.com/98016
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
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Updates #22460.
Change-Id: Ieaca94385c3bb88dcc8351c3866b4b0e2a1412b5
Reviewed-on: https://go-review.googlesource.com/92701
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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This replaces frame size -4/-8 with the NOFRAME flag in mips and
mips64 assembly.
This was automated with:
sed -i -e 's/\(^TEXT.*[A-Z]\),\( *\)\$-[84]/\1|NOFRAME,\2$0/' $(find -name '*_mips*.s')
Plus a manual fix to mkduff.go.
The go binary is identical on both architectures before and after this
change.
Change-Id: I0310384d1a584118c41d1cd3a042bb8ea7227efb
Reviewed-on: https://go-review.googlesource.com/92044
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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Currently systemstack always calls its argument, even if we're already
on the system stack. Unfortunately, traceback with _TraceJump stops at
the first systemstack it sees, which often cuts off runtime stacks
early in profiles.
Fix this by performing a tail call if we're already on the system
stack. This eliminates it from the traceback entirely, so it won't
stop prematurely (or all get mushed into a single node in the profile
graph).
Change-Id: Ibc69e8765e899f8d3806078517b8c7314da196f4
Reviewed-on: https://go-review.googlesource.com/74050
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
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Currently, newstack and gogo have write barriers for maintaining the
context register saved in g.sched.ctxt. This is troublesome, because
newstack can be called from go:nowritebarrierrec places that can't
allow write barriers. It happens to be benign because g.sched.ctxt
will always be nil on entry to newstack *and* it so happens the
incoming ctxt will also always be nil in these contexts (I
think/hope), but this is playing with fire. It's also desirable to
mark newstack go:nowritebarrierrec to prevent any other, non-benign
write barriers from creeping in, but we can't do that right now
because of this one write barrier.
Fix all of this by observing that g.sched.ctxt is really just a saved
live pointer register. Hence, we can shade it when we scan g's stack
and otherwise move it back and forth between the actual context
register and g.sched.ctxt without write barriers. This means we can
save it in morestack along with all of the other g.sched, eliminate
the save from newstack along with its troublesome write barrier, and
eliminate the shenanigans in gogo to invoke the write barrier when
restoring it.
Once we've done all of this, we can mark newstack
go:nowritebarrierrec.
Fixes #22385.
For #22460.
Change-Id: I43c24958e3f6785b53c1350e1e83c2844e0d1522
Reviewed-on: https://go-review.googlesource.com/72553
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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Now that getcallerpc is a compiler intrinsic on x86 and non-x86
platforms don't need the argument, we can drop it.
Sadly, this doesn't let us remove any dummy arguments since all of
those cases also use getcallersp, which still takes the argument
pointer, but this is at least an improvement.
Change-Id: I9c34a41cf2c18cba57f59938390bf9491efb22d2
Reviewed-on: https://go-review.googlesource.com/65474
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
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eqstring is only called for strings with equal lengths.
Instead of pushing a pointer and length for each argument string
on the stack we can omit pushing one of the lengths on the stack.
Changing eqstrings signature to eqstring(*uint8, *uint8, int) bool
to implement the above optimization would make it very similar to the
existing memequal(*any, *any, uintptr) bool function.
Since string lengths are positive we can avoid code redundancy and
use memequal instead of using eqstring with an optimized signature.
go command binary size reduced by 4128 bytes on amd64.
name old time/op new time/op delta
CompareStringEqual 6.03ns ± 1% 5.71ns ± 1% -5.23% (p=0.000 n=19+18)
CompareStringIdentical 2.88ns ± 1% 3.22ns ± 7% +11.86% (p=0.000 n=20+20)
CompareStringSameLength 4.31ns ± 1% 4.01ns ± 1% -7.17% (p=0.000 n=19+19)
CompareStringDifferentLength 0.29ns ± 2% 0.29ns ± 2% ~ (p=1.000 n=20+20)
CompareStringBigUnaligned 64.3µs ± 2% 64.1µs ± 3% ~ (p=0.164 n=20+19)
CompareStringBig 61.9µs ± 1% 61.6µs ± 2% -0.46% (p=0.033 n=20+19)
Change-Id: Ice15f3b937c981f0d3bc8479a9ea0d10658ac8df
Reviewed-on: https://go-review.googlesource.com/53650
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
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Intrinsic enabled on all architectures,
runtime asm implementation removed on all architectures.
Fixes #21258
Change-Id: I2cb86d460b497c2f287a5b3df5c37fdb231c23a7
Reviewed-on: https://go-review.googlesource.com/53411
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: David Chase <drchase@google.com>
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The only non test user of the assembler prefetch functions is the
heapBits.prefetch function which is itself unused.
The runtime prefetch functions have no functionality on most platforms
and are not inlineable since they are written in assembler. The function
call overhead eliminates the performance gains that could be achieved with
prefetching and would degrade performance for platforms where the functions
are no-ops.
If prefetch functions are needed back again later they can be improved
by avoiding the function call overhead and implementing them as intrinsics.
Change-Id: I52c553cf3607ffe09f0441c6e7a0a818cb21117d
Reviewed-on: https://go-review.googlesource.com/44370
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
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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>
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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>
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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>
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I meant to say ~7, instead of ^7, in the review.
Fix build.
Change-Id: I5060bbcd98b4ab6f00251fdb68b6b35767e5acf1
Reviewed-on: https://go-review.googlesource.com/34411
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
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Change-Id: Ib425ead7b340672837d3cb983bd785488706bd6d
Reviewed-on: https://go-review.googlesource.com/34314
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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Only exe buildmode without cgo supported.
Change-Id: Id104a79a99d3285c04db00fd98b8affa94ea3c37
Reviewed-on: https://go-review.googlesource.com/31487
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
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