When callMethod calls the underlying method, after reflectcall
it gets the result registers in "Ints" slots but not in "Ptrs"
slots. If the GC runs at this point, it may lose track of those
pointers and free the memory they point to.
To make sure the GC sees the pointer results, copy "Ints" to
"Ptrs", and keep them alive until we return to the caller.
This fixes test/fixedbugs/issue27695.go with register ABI.
Change-Id: I4092c91bcbd6954683740a12d91d689900446875
Reviewed-on: https://go-review.googlesource.com/c/go/+/309909
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
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Reviewed-by: Michael Knyszek <mknyszek@google.com>
For #42076Fixes#45451
Change-Id: I69646226d3480d5403205412ddd13c0cfc2c8a53
Reviewed-on: https://go-review.googlesource.com/c/go/+/308970
Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
t is the type of the function that was called
tv is the type of the result
This fixes the failures for
GOEXPERIMENT=regabi,regabiargs go test go test text/template
GOEXPERIMENT=regabi,regabiargs go test go test html/template
Updates #40724.
Change-Id: Ic9b02d72d18ff48c9de1209987cc39da619c2241
Reviewed-on: https://go-review.googlesource.com/c/go/+/308189
Trust: David Chase <drchase@google.com>
Run-TryBot: David Chase <drchase@google.com>
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Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This change finishes off functionality register ABI for the reflect
package.
Specifically, it implements a call on a MakeFunc'd value by performing
the reverse process that reflect.Value.Call does, using the same ABI
steps. It implements a call on a method value created by reflect by
translating between the method value's ABI to the method's ABI.
Tests are added for both cases.
For #40724.
Change-Id: I302820b61fc0a8f94c5525a002bc02776aef41af
Reviewed-on: https://go-review.googlesource.com/c/go/+/298670
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
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>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
The bug was introduced by https://golang.org/cl/220844.
Updates #42792.
Fixes#42835.
Change-Id: I03065c7526488aded35ef2f800b7162e1606877a
Reviewed-on: https://go-review.googlesource.com/c/go/+/273326
Trust: Robert Griesemer <gri@golang.org>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
This reverts commit 8f26b57f9a.
Reason for revert: break a bunch of code, include standard library.
Fixes#42123
Change-Id: Ife90ecbafd2cb395623d1db555fbfc9c1b0098e0
Reviewed-on: https://go-review.googlesource.com/c/go/+/264026
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
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Reviewed-by: Russ Cox <rsc@golang.org>
pointers to go:notinheap types should be treated as scalars. That
means they shouldn't be stored directly in interfaces, or directly
in reflect.Value.ptr.
Also be sure to use uintpr to compare such pointers in reflect.DeepEqual.
Fixes#42076
Change-Id: I53735f6d434e9c3108d4940bd1bae14c61ef2a74
Reviewed-on: https://go-review.googlesource.com/c/go/+/264480
Trust: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, mhdr/methods is emitted with the same len/cap. There's no way
to distinguish between exported and non-exported methods statically.
This CL splits mhdr/methods into two parts, use "len" for number of
exported methods, and "cap" for all methods. This fixes the bug in
issue #22075, which intends to return the number of exported methods but
currently return all methods.
Note that with this encoding, we still can access either
all/exported-only/non-exported-only methods:
mhdr[:cap(mhdr)] // all methods
mhdr // exported methods
mhdr[len(mhdr):cap(mhdr)] // non-exported methods
Thank to Matthew Dempsky (@mdempsky) for suggesting this encoding.
Fixes#22075
Change-Id: If662adb03ccff27407d55a5578a0ed05a15e7cdd
Reviewed-on: https://go-review.googlesource.com/c/go/+/259237
Trust: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
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Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
In the common case (<1KB types), no allocation is required
by reflect.Zero.
Also use memclr instead of memmove in Set when the source
is known to be zero.
Fixes#33136
Change-Id: Ic66871930fbb53328032e587153ebd12995ccf55
Reviewed-on: https://go-review.googlesource.com/c/go/+/192331
Trust: Keith Randall <khr@golang.org>
Run-TryBot: Keith Randall <khr@golang.org>
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Reviewed-by: Martin Möhrmann <moehrmann@google.com>
reflect.assignTo writes to the target using write barriers. Make sure
that the memory it is writing to is zeroed, so the write barrier does
not read pointers from uninitialized memory.
Fixes#39541
Change-Id: Ia64b2cacc193bffd0c1396bbce1dfb8182d4905b
Reviewed-on: https://go-review.googlesource.com/c/go/+/238760
Run-TryBot: Keith Randall <khr@golang.org>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, Value.Addr collapses flagRO, which is a combination of
flagEmbedRO and flagStickyRO, to flagStickyRO. This causes exported
fields of unexported anonymous field from Value.Addr.Elem read only.
This commit fix this by keeping all bits of flagRO from origin
value in Value.Addr. This should be safe due to following reasons:
* Result of Value.Addr is not CanSet because of it is not CanAddr
but not flagRO.
* Addr.Elem get same flagRO as origin, so it should behave same as
origin in CanSet.
Fixes#32772.
Change-Id: I79e086628c0fb6569a50ce63f3b95916f997eda1
GitHub-Last-Rev: 78e280e6d0
GitHub-Pull-Request: golang/go#32787
Reviewed-on: https://go-review.googlesource.com/c/go/+/183937
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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The new package "internal/unsafeheader" depends only on "unsafe", and
provides declarations equivalent to reflect.StringHeader and
reflect.SliceHeader but with Data fields of the proper unsafe.Pointer
type (instead of uintptr).
Unlike the types it replaces, the "internal/unsafeheader" package has
a regression test to ensure that its header types remain equivalent to
the declarations provided by the "reflect" package.
Since "internal/unsafeheader" has almost no dependencies, it can be
used in other low-level packages such as "syscall" and "reflect".
This change is based on the corresponding x/sys change in CL 231177.
Fixes#37805
Updates #19367
Change-Id: I7a6d93ef8dd6e235bcab94e7c47270aad047af31
Reviewed-on: https://go-review.googlesource.com/c/go/+/231223
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Allocate the runcases slice on the stack if the number
of select cases is small (up to 4).
Found while looking at production profiles of common
proto based RPC server framework code in Google which do
not have a large number of cases.
name old time/op new time/op delta
Select/1 147ns ± 2% 120ns ± 6% -18.32% (p=0.000 n=7+10)
Select/4 316ns ± 5% 249ns ± 2% -21.23% (p=0.000 n=10+10)
Select/8 516ns ± 3% 515ns ± 3% ~ (p=0.858 n=10+9)
name old alloc/op new alloc/op delta
Select/1 96.0B ± 0% 64.0B ± 0% -33.33% (p=0.000 n=10+10)
Select/4 336B ± 0% 208B ± 0% -38.10% (p=0.000 n=10+10)
Select/8 672B ± 0% 672B ± 0% ~ (all equal)
name old allocs/op new allocs/op delta
Select/1 4.00 ± 0% 3.00 ± 0% -25.00% (p=0.000 n=10+10)
Select/4 7.00 ± 0% 6.00 ± 0% -14.29% (p=0.000 n=10+10)
Select/8 11.0 ± 0% 11.0 ± 0% ~ (all equal)
Change-Id: I1687e74fc8e86606a27f03fa8a561bcfb68775d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/230657
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Given:
type u struct{}
func (u) M() {}
type t struct { u; u2 u }
var v = reflect.ValueOf(t{})
Package reflect allows:
v.Method(0) // v.M
v.Field(0).Method(0) // v.u.M
but panics from:
v.Field(1).Method(0) // v.u2.M
because u2 is not an exported field. However, u is not an exported
field either, so this is inconsistent.
It seems like this behavior originates from #12367, where it was
decided to allow traversing unexported embedded fields to be able to
access their exported fields, since package reflect doesn't provide an
alternative way to access promoted fields directly.
But extending that logic to promoted *methods* was inappropriate,
because package reflect's normal method handling logic already handles
promoted methods correctly. This CL corrects that mistake.
Fixes#38521.
Change-Id: If65008965f35927b4e7927cddf8614695288eb19
Reviewed-on: https://go-review.googlesource.com/c/go/+/228902
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: Ian Lance Taylor <iant@golang.org>
This was accidentally broken in CL 166462, which introduce another
function in the panicking path without adjusting the argument to
runtime.Caller.
Change-Id: Ib6f9ed8673fefd458c7a4e3a918c45c5b31ca552
Reviewed-on: https://go-review.googlesource.com/c/go/+/229082
Run-TryBot: Ian Lance Taylor <iant@golang.org>
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Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Trying this CL again, with a test that skips 387.
When converting from float32->float64->float32, any signal NaNs
get converted to quiet NaNs. Avoid that so using reflect.Value.Convert
between two float32 types keeps the signal bit of NaNs.
Skip the test on 387. I don't see any sane way of ensuring that a
float load + float store is faithful on that platform.
Fixes#36400
Change-Id: Ic316c74ddc155632e40424e207375b5d50dcd853
Reviewed-on: https://go-review.googlesource.com/c/go/+/221792
Run-TryBot: Keith Randall <khr@golang.org>
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Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Instead use string(r) where r has type rune.
This is in preparation for a vet warning for string(i).
Updates #32479
Change-Id: Ic205269bba1bd41723950219ecfb67ce17a7aa79
Reviewed-on: https://go-review.googlesource.com/c/go/+/220844
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Akhil Indurti <aindurti@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Toshihiro Shiino <shiino.toshihiro@gmail.com>
When converting from float32->float64->float32, any signal NaNs
get converted to quiet NaNs. Avoid that so using reflect.Value.Convert
between two float32 types keeps the signal bit of NaNs.
Update #36400
Change-Id: Ic4dd04c4be7189d2171d12b7e4e8f7cf2fb22bb4
Reviewed-on: https://go-review.googlesource.com/c/go/+/213497
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The runtime implementation of select has an upper limit on the number of
select cases that are supported in order to maintain low stack memory
usage. Rather than support an arbitrary number of select cases, we've
opted to panic early with a useful message pointing the user directly
at the problem.
Fixes#37350
Change-Id: Id129ba281ae120387e681ef96be8adcf89725840
Reviewed-on: https://go-review.googlesource.com/c/go/+/220583
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Go specification says: A value x is assignable to a variable of type T if x
is a bidirectional channel value, T is a channel type, x's type V and T have
identical element types, and at least one of V or T is not a defined type.
However, the current reflection implementation is incorrect which makes
"x is assignable to T" even if type V and T are both defined type.
The current reflection implementation also mistakes the base types of two
non-defined pointer types share the same underlying type when the two
base types satisfy the above mentioned special channel assignability rule.
Fixes#29469
Change-Id: Ia4b9c4ac47dc8e76a11faef422b2e5c5726b78b3
GitHub-Last-Rev: 487c20a564
GitHub-Pull-Request: golang/go#29739
Reviewed-on: https://go-review.googlesource.com/c/go/+/157822
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This CL adds -d=checkptr as a compile-time option for adding
instrumentation to check that Go code is following unsafe.Pointer
safety rules dynamically. In particular, it currently checks two
things:
1. When converting unsafe.Pointer to *T, make sure the resulting
pointer is aligned appropriately for T.
2. When performing pointer arithmetic, if the result points to a Go
heap object, make sure we can find an unsafe.Pointer-typed operand
that pointed into the same object.
These checks are currently disabled for the runtime, and can also be
disabled through a new //go:nocheckptr annotation. The latter is
necessary for functions like strings.noescape, which intentionally
violate safety rules to workaround escape analysis limitations.
Fixes#22218.
Change-Id: If5a51273881d93048f74bcff10a3275c9c91da6a
Reviewed-on: https://go-review.googlesource.com/c/go/+/162237
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
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Reviewed-by: Keith Randall <khr@golang.org>
Part 1: CL 199499 (GOOS nacl)
Part 2: CL 200077 (amd64p32 files, toolchain)
Part 3: stuff that arguably should've been part of Part 2, but I forgot
one of my grep patterns when splitting the original CL up into
two parts.
This one might also have interesting stuff to resurrect for any future
x32 ABI support.
Updates #30439
Change-Id: I2b4143374a253a003666f3c69e776b7e456bdb9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/200318
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Make it clear that IsValid checks that we have valid
reflect.Value and not the value of `v`
fixes#34152
Change-Id: Ib3d359eeb3a82bf733b9ed17c777fc4c143bc29c
Reviewed-on: https://go-review.googlesource.com/c/go/+/193841
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Right now we generate hash functions for all types, just in case they
are used as map keys. That's a lot of wasted effort and binary size
for types which will never be used as a map key. Instead, generate
hash functions only for types that we know are map keys.
Just doing that is a bit too simple, since maps with an interface type
as a key might have to hash any concrete key type that implements that
interface. So for that case, implement hashing of such types at
runtime (instead of with generated code). It will be slower, but only
for maps with interface types as keys, and maybe only a bit slower as
the aeshash time probably dominates the dispatch time.
Reorg where we keep the equals and hash functions. Move the hash function
from the key type to the map type, saving a field in every non-map type.
That leaves only one function in the alg structure, so get rid of that and
just keep the equal function in the type descriptor itself.
cmd/go now has 10 generated hash functions, instead of 504. Makes
cmd/go 1.0% smaller. Update #6853.
Speed on non-interface keys is unchanged. Speed on interface keys
is ~20% slower:
name old time/op new time/op delta
MapInterfaceString-8 23.0ns ±21% 27.6ns ±14% +20.01% (p=0.002 n=10+10)
MapInterfacePtr-8 19.4ns ±16% 23.7ns ± 7% +22.48% (p=0.000 n=10+8)
Change-Id: I7c2e42292a46b5d4e288aaec4029bdbb01089263
Reviewed-on: https://go-review.googlesource.com/c/go/+/191198
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
When calling a function obtained from reflect.Value.Method (or
MethodByName), we copy the arguments from the caller frame, which
does not include the receiver, to a new frame to call the actual
method, which does include the receiver. Here we need to align
the first (non-receiver) argument. As the receiver is pointer
sized, it is generally naturally aligned, except on amd64p32,
where the argument can have larger alignment, and this aligning
becomes necessary.
Fixes#33628.
Change-Id: I5bea0e20173f06d1602c5666d4f334e3d0de5c1e
Reviewed-on: https://go-review.googlesource.com/c/go/+/190297
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
There is a subtle distinction between a value
*being* the zero value vs being *equal to* the zero value.
This was discussed at length in #31450.
Using "a zero value" in the docs suggests that there may
be more than zero value. That is possible on the "equal to
zero value" reading, but not the "is zero" reading that we
selected for the semantics of IsZero.
This change attempts to prevent any confusion on this front by
switching to "the zero value" in the documentation.
And while we're here, eliminate a double-space.
(Darn macbook keyboards.)
Change-Id: Iaa02ba297438793f5a90be9919a4d53baef92f8e
Reviewed-on: https://go-review.googlesource.com/c/go/+/182617
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Before this CL we used to panic with "nil pointer dereference" because
the value we're calling assignTo on is the zero Value. Provide a better
error message.
Fixes#28748
Change-Id: I7dd4c9e30b599863664d91e78cc45878d8b0052e
Reviewed-on: https://go-review.googlesource.com/c/go/+/175440
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Instead of requiring exact type match, allow assignment conversions
(those conversions allowed in the language spec without a cast) on the
returned values.
Particularly useful when the type being returned is an interface type,
but the Value actually returned is a concrete value implementing that
type (as it is tricky to return a Value which has interface type).
RELNOTE=y
Fixes#28761
Change-Id: I69eef07ca51690b2086dfa1eb549db5e4724c657
Reviewed-on: https://go-review.googlesource.com/c/go/+/174531
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The spec carefully and consistently uses "key" and "element"
as map terminology. The implementation, not so much.
This change attempts to make the implementation consistently
hew to the spec's terminology. Beyond consistency, this has
the advantage of avoid some confusion and naming collisions,
since v and value are very generic and commonly used terms.
I believe that I found all everything, but there are a lot of
non-obvious places for these to hide, and grepping for them is hard.
Hopefully this change changes enough of them that we will start using
elem going forward. Any remaining hidden cases can be removed ad hoc
as they are discovered.
The only externally-facing part of this change is in package reflect,
where there is a minor doc change and a function parameter name change.
Updates #27167
Change-Id: I2f2d78f16c360dc39007b9966d5c2046a29d3701
Reviewed-on: https://go-review.googlesource.com/c/go/+/174523
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
mustBe was barely over budget, so manually inlining the first flag.kind
call is enough. Add a TODO to reverse that in the future, once the
compiler gets better.
mustBeExported and mustBeAssignable were over budget by a larger amount,
so add slow path functions instead. This is the same strategy used in
the sync package for common methods like Once.Do, for example.
Lots of exported reflect.Value methods call these assert-like unexported
methods, so avoiding the function call overhead in the common case does
shave off a percent from most exported APIs.
Finally, add the methods to TestIntendedInlining.
While at it, replace a couple of uses of the 0 Kind with its descriptive
name, Invalid.
name old time/op new time/op delta
Call-8 68.0ns ± 1% 66.8ns ± 1% -1.81% (p=0.000 n=10+9)
PtrTo-8 8.00ns ± 2% 7.83ns ± 0% -2.19% (p=0.000 n=10+9)
Updates #7818.
Change-Id: Ic1603b640519393f6b50dd91ec3767753eb9e761
Reviewed-on: https://go-review.googlesource.com/c/go/+/166462
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
We are copying the results to uninitialized stack space. Write
barrier is not needed.
Fixes#30041.
Change-Id: Ia91d74dbafd96dc2bd92de0cb479808991dda03e
Reviewed-on: https://go-review.googlesource.com/c/160737
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
UnsafePointer is a valid type kind to call IsNil on.
Fixes#29381
Change-Id: Iaf65d582c67f4be52cd1885badf40f174920500b
Reviewed-on: https://go-review.googlesource.com/c/155797
Run-TryBot: Andrew Bonventre <andybons@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
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>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
During a call to a reflect-generated function or method (via
makeFuncStub or methodValueCall), when should we scan the return
values?
When we're starting a reflect call, the space on the stack for the
return values is not initialized yet, as it contains whatever junk was
on the stack of the caller at the time. The return space must not be
scanned during a GC.
When we're finishing a reflect call, the return values are
initialized, and must be scanned during a GC to make sure that any
pointers in the return values are found and their referents retained.
When the GC stack walk comes across a reflect call in progress on the
stack, it needs to know whether to scan the results or not. It doesn't
know the progress of the reflect call, so it can't decide by
itself. The reflect package needs to tell it.
This CL adds another slot in the frame of makeFuncStub and
methodValueCall so we can put a boolean in there which tells the
runtime whether to scan the results or not.
This CL also adds the args length to reflectMethodValue so the
runtime can restrict its scanning to only the args section (not the
results) if the reflect package says the results aren't ready yet.
Do a delicate dance in the reflect package to set the "results are
valid" bit. We need to make sure we set the bit only after we've
copied the results back to the stack. But we must set the bit before
we drop reflect's copy of the results. Otherwise, we might have a
state where (temporarily) no one has a live copy of the results.
That's the state we were observing in issue #27695 before this CL.
The bitmap used by the runtime currently contains only the args.
(Actually, it contains all the bits, but the size is set so we use
only the args portion.) This is safe for early in a reflect call, but
unsafe late in a reflect call. The test issue27695.go demonstrates
this unsafety. We change the bitmap to always include both args
and results, and decide at runtime which portion to use.
issue27695.go only has a test for method calls. Function calls were ok
because there wasn't a safepoint between when reflect dropped its copy
of the return values and when the caller is resumed. This may change
when we introduce safepoints everywhere.
This truncate-to-only-the-args was part of CL 9888 (in 2015). That
part of the CL fixed the problem demonstrated in issue27695b.go but
introduced the problem demonstrated in issue27695.go.
TODO, in another CL: simplify FuncLayout and its test. stack return
value is now identical to frametype.ptrdata + frametype.gcdata.
Fixes#27695
Change-Id: I2d49b34e34a82c6328b34f02610587a291b25c5f
Reviewed-on: https://go-review.googlesource.com/137440
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Fix the code to use write barriers on heap memory, and no
write barriers on stack memory.
These errors were discoverd as part of fixing #27695. They may
have something to do with that issue, but hard to be sure.
The core cause is different, so this fix is a separate CL.
Update #27695
Change-Id: Ib005f6b3308de340be83c3d07d049d5e316b1e3c
Reviewed-on: https://go-review.googlesource.com/137438
Reviewed-by: Austin Clements <austin@google.com>
Example of use:
iter := reflect.ValueOf(m).MapRange()
for iter.Next() {
k := iter.Key()
v := iter.Value()
...
}
See issue golang/go#11104
Q. Are there any benchmarks that would exercise the new calls to
copyval in existing code?
Change-Id: Ic469fcab5f1d9d853e76225f89bde01ee1d36e7a
Reviewed-on: https://go-review.googlesource.com/33572
Reviewed-by: Keith Randall <khr@golang.org>
On the API level this is just an update of the documentation to match
the current spec more closely.
On the implementation side, this is a rename of various unexported names.
For #22005.
Change-Id: Ie5ae32f3b10f003805240efcceab3d0fd373cd51
Reviewed-on: https://go-review.googlesource.com/112717
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If the type of Type is known to be *rtype than the common
function is a no-op and does not need to be called.
name old time/op new time/op delta
New 31.0ns ± 5% 30.2ns ± 4% -2.74% (p=0.008 n=20+20)
Change-Id: I5d00346dbc782e34c530166d1ee0499b24068b51
Reviewed-on: https://go-review.googlesource.com/96115
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
It's not safe to do p+x with unsafe if that would point past the
end of the object. (Valid in C, not safe in Go.)
Pass a "whySafe" reason (compiled away) to explain at each
call site why it's safe.
Fixes#21733.
Change-Id: I5da8c25bde66f5c9beac232f2135dcab8e8bf3b1
Reviewed-on: https://go-review.googlesource.com/80738
Reviewed-by: Austin Clements <austin@google.com>
Call is meant to mirror the language semantics, which allow:
var r io.ReadWriter
f := func(io.Reader){}
f(r)
even though the conversion from io.ReadWriter to io.Reader is
being applied to a nil interface. This is different from an explicit
conversion:
_ = r.(io.Reader)
f(r.(io.Reader))
Both of those lines panic, but the implicit conversion does not.
By using E2I, which is the implementation of the explicit conversion,
the reflect.Call equivalent of f(r) was inadvertently panicking.
Avoid the panic.
Fixes#22143.
Change-Id: I6b2f5b808e0cd3b89ae8bc75881e307bf1c25558
Reviewed-on: https://go-review.googlesource.com/80736
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
All of these had a return or break in the else body, so flipping the
condition means we can unindent and simplify.
Change-Id: If93e97504480d18a0dac3f2c8ffe57ab8bcb929c
Reviewed-on: https://go-review.googlesource.com/74190
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This somewhat mirrors the special case behavior of the copy built-in.
Fixes#22215
Change-Id: Ic353003ad3de659d3a6b4e9d97295b42510f3bf7
Reviewed-on: https://go-review.googlesource.com/70431
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Currently, methods are sorted by name. This happens to guarantee that
exported ASCII methods appear before non-exported ASCII methods, but
this breaks down when Unicode method names are considered.
Type.Method already accounts for this by always indexing into the
slice returned by exportedMethods. This CL makes Value.Method do the
same.
Fixes#22073.
Change-Id: I9bfc6bbfb7353e0bd3c439a15d1c3da60d16d209
Reviewed-on: https://go-review.googlesource.com/66770
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The reflect API normally grants only read-only access to non-exported
fields, but it specially handles non-exported embedded fields so that
users can still fully access promoted fields and methods. For example,
if v.Field(i) refers to a non-exported embedded field, it would be
limited to RO access. But if v.Field(i).Field(j) is an exported field,
then the resulting Value will have full access.
However, the way this was implemented allowed other operations to be
interspersed between the Field calls, which could grant inappropriate
access.
Relatedly, Elem() is safe to use on pointer-embeddings, but it was
also being allowed on embeddings of interface types. This is
inappropriate because it could allow accessing methods of the dynamic
value's complete method set, not just those that were promoted via the
interface embedding.
Fixes#22031.
Fixes#22053.
Change-Id: I9db9be88583f1c1d80c1b4705a76f23a4379182f
Reviewed-on: https://go-review.googlesource.com/66331
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
If a function with nonzero frame but zero-sized return value is
Call'd, we may write a past-the-end pointer in preparing the
return Values. Fix by return the zero value for zero-sized
return value.
Fixes#21717.
Change-Id: I5351cd86d898467170a888b4c3fc9392f0e7aa3b
Reviewed-on: https://go-review.googlesource.com/60811
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
