This change fixes a race condition between beforeIdle waking up the
innermost event handler and a timer causing a different goroutine to
wake up at the exact same moment. This messes up the wasm event handling
and leads to memory corruption. The solution is to make beforeIdle
return the goroutine that must run next and have findrunnable pick
this goroutine without considering timers again.
Fixes#38093Fixes#38574
Change-Id: Iffbe99411d25c2730953d1c8b0741fd892f8e540
Reviewed-on: https://go-review.googlesource.com/c/go/+/230178
Run-TryBot: Richard Musiol <neelance@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
CL 233857 fixed the underlying issue for #37246,
which had arisen again as #38916.
Add the test case from #37246 to ensure it stays fixed.
Fixes#37246
Change-Id: If7fd75a096d2ce4364dc15509253c3882838161d
Reviewed-on: https://go-review.googlesource.com/c/go/+/233941
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Munday <mike.munday@ibm.com>
When tuple generators and selectors are eliminated as part of the
CSE pass we may end up with tuple selectors that are in different
blocks to the tuple generators that they correspond to. This breaks
the invariant that tuple generators and their corresponding
selectors must be in the same block. Therefore after CSE this
situation must be corrected.
Unfortunately the fixup code did not take into account that selectors
could be eliminated by CSE. It assumed that only the tuple generators
could be eliminated. In some situations this meant that it got into
a state where it was replacing references to selectors with references
to dead selectors in the wrong block.
To fix this we move the fixup code after the CSE rewrites have been
applied. This removes any difficult-to-reason-about interactions
with the CSE rewriter.
Fixes#38916.
Change-Id: I2211982dcdba399d03299f0a819945b3eb93b291
Reviewed-on: https://go-review.googlesource.com/c/go/+/233857
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Taking over Zach's CL 212277. Just cleaned up and added a test.
For a positive, signed integer, an arithmetic right shift of count
(bit-width - 1) equals zero. e.g. int64(22) >> 63 -> 0. This CL makes
prove replace these right shifts with a zero-valued constant.
These shifts may arise in source code explicitly, but can also be
created by the generic rewrite of signed division by a power of 2.
// Signed divide by power of 2.
// n / c = n >> log(c) if n >= 0
// = (n+c-1) >> log(c) if n < 0
// We conditionally add c-1 by adding n>>63>>(64-log(c))
(first shift signed, second shift unsigned).
(Div64 <t> n (Const64 [c])) && isPowerOfTwo(c) ->
(Rsh64x64
(Add64 <t> n (Rsh64Ux64 <t>
(Rsh64x64 <t> n (Const64 <typ.UInt64> [63]))
(Const64 <typ.UInt64> [64-log2(c)])))
(Const64 <typ.UInt64> [log2(c)]))
If n is known to be positive, this rewrite includes an extra Add and 2
extra Rsh. This CL will allow prove to replace one of the extra Rsh with
a 0. That replacement then allows lateopt to remove all the unneccesary
fixups from the generic rewrite.
There is a rewrite rule to handle this case directly:
(Div64 n (Const64 [c])) && isNonNegative(n) && isPowerOfTwo(c) ->
(Rsh64Ux64 n (Const64 <typ.UInt64> [log2(c)]))
But this implementation of isNonNegative really only handles constants
and a few special operations like len/cap. The division could be
handled if the factsTable version of isNonNegative were available.
Unfortunately, the first opt pass happens before prove even has a
chance to deduce the numerator is non-negative, so the generic rewrite
has already fired and created the extra Ops discussed above.
Fixes#36159
By Printf count, this zeroes 137 right shifts when building std and cmd.
Change-Id: Iab486910ac9d7cfb86ace2835456002732b384a2
Reviewed-on: https://go-review.googlesource.com/c/go/+/232857
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Improve the error user experience when users try to set/refer
to unexported fields and methods of struct literals, by directly saying
"cannot refer to unexported field or method"
Fixes#31053
Change-Id: I6fd3caf64b7ca9f9d8ea60b7756875e340792d59
Reviewed-on: https://go-review.googlesource.com/c/go/+/201657
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Omits printing the file:line:column when trying to
open non-existent files
Given:
go tool compile x.go
* Before:
x.go:0: open x.go: no such file or directory
* After:
open x.go: no such file or directory
Reverts the revert in CL 231043 by only fixing the case
of non-existent errors which is what the original bug
was about. The fix for "permission errors" will come later
on when I have bandwidth to investigate the differences
between running with root and why os.Open works for some
builders and not others.
Fixes#36437
Change-Id: I9c8a0981ad708b504bb43990a4105b42266fa41f
Reviewed-on: https://go-review.googlesource.com/c/go/+/230941
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
match:
m = make([]T, x); copy(m, s)
for pointer free T and x==len(s) rewrite to:
m = mallocgc(x*elemsize(T), nil, false); memmove(&m, &s, x*elemsize(T))
otherwise rewrite to:
m = makeslicecopy([]T, x, s)
This avoids memclear and shading of pointers in the newly created slice
before the copy.
With this CL "s" is only be allowed to bev a variable and not a more
complex expression. This restriction could be lifted in future versions
of this optimization when it can be proven that "s" is not referencing "m".
Triggers 450 times during make.bash..
Reduces go binary size by ~8 kbyte.
name old time/op new time/op delta
MakeSliceCopy/mallocmove/Byte 71.1ns ± 1% 65.8ns ± 0% -7.49% (p=0.000 n=10+9)
MakeSliceCopy/mallocmove/Int 71.2ns ± 1% 66.0ns ± 0% -7.27% (p=0.000 n=10+8)
MakeSliceCopy/mallocmove/Ptr 104ns ± 4% 99ns ± 1% -5.13% (p=0.000 n=10+10)
MakeSliceCopy/makecopy/Byte 70.3ns ± 0% 68.0ns ± 0% -3.22% (p=0.000 n=10+9)
MakeSliceCopy/makecopy/Int 70.3ns ± 0% 68.5ns ± 1% -2.59% (p=0.000 n=9+10)
MakeSliceCopy/makecopy/Ptr 102ns ± 0% 99ns ± 1% -2.97% (p=0.000 n=9+9)
MakeSliceCopy/nilappend/Byte 75.4ns ± 0% 74.9ns ± 2% -0.63% (p=0.015 n=9+9)
MakeSliceCopy/nilappend/Int 75.6ns ± 0% 76.4ns ± 3% ~ (p=0.245 n=9+10)
MakeSliceCopy/nilappend/Ptr 107ns ± 0% 108ns ± 1% +0.93% (p=0.005 n=9+10)
Fixes#26252
Change-Id: Iec553dd1fef6ded16197216a472351c8799a8e71
Reviewed-on: https://go-review.googlesource.com/c/go/+/146719
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The {AND,OR,XOR}const ops can only take an int32 as an argument.
Make sure that when rewriting a BTx op to one of these, the result
has no high-order bits.
Fixes#38746
Change-Id: Ia7c5f76952329f60974bc033c29a5433610f3b28
Reviewed-on: https://go-review.googlesource.com/c/go/+/231977
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This reverts commit 4f7053c87f.
Reason for revert: Newly added test is failing on several builders.
Change-Id: I22dcbfebf2f57735b2f479886bbeb623f95b132f
Reviewed-on: https://go-review.googlesource.com/c/go/+/231043
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Omits printing the file:line:column when trying to open either
* non-existent files
* files without permission
Given:
go tool compile x.go
For either of x.go not existing, or if no read permissions:
* Before:
x.go:0: open x.go: no such file or directory
x.go:0: open x.go: permission denied
* After:
open x.go: no such file or directory
open x.go: permission denied
While here, noticed an oddity with the Linux builders, that appear
to always be running under root, hence the test for permission errors
with 0222 -W-*-W-*-W- can't pass on linux-amd64 builders.
The filed bug is #38608.
Fixes#36437
Change-Id: I9645ef73177c286c99547e3a0f3719fa07b35cb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/229357
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
We set up static symbols during walk that
we later make copies of to initialize local variables.
It is difficult to ascertain at that time exactly
when copying a symbol is profitable vs locally
initializing an autotmp.
During SSA, we are much better placed to optimize.
This change recognizes when we are copying from a
global readonly all-zero symbol and replaces it with
direct zeroing.
This often allows the all-zero symbol to be
deadcode eliminated at link time.
This is not ideal--it makes for large object files,
and longer link times--but it is the cleanest fix I could find.
This makes the final binary for the program in #38554
shrink from >500mb to ~2.2mb.
It also shrinks the standard binaries:
file before after Δ %
addr2line 4412496 4404304 -8192 -0.186%
buildid 2893816 2889720 -4096 -0.142%
cgo 4841048 4832856 -8192 -0.169%
compile 19926480 19922432 -4048 -0.020%
cover 5281816 5277720 -4096 -0.078%
link 6734648 6730552 -4096 -0.061%
nm 4366240 4358048 -8192 -0.188%
objdump 4755968 4747776 -8192 -0.172%
pprof 14653060 14612100 -40960 -0.280%
trace 11805940 11777268 -28672 -0.243%
vet 7185560 7181416 -4144 -0.058%
total 113588440 113465560 -122880 -0.108%
And not just by removing unnecessary symbols;
the program text shrinks a bit as well.
Fixes#38554
Change-Id: I8381ae6084ae145a5e0cd9410c451e52c0dc51c8
Reviewed-on: https://go-review.googlesource.com/c/go/+/229704
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
This CL uses fixVariadicCall before escape analyzing function calls.
This has a number of benefits, though also some minor obstacles:
Most notably, it allows us to remove ODDDARG along with the logic
involved in setting it up, manipulating EscHoles, and later copying
its escape analysis flags to the actual slice argument. Instead, we
uniformly handle all variadic calls the same way. (E.g., issue31573.go
is updated because now f() and f(nil...) are handled identically.)
It also allows us to simplify handling of builtins and generic
function calls. Previously handling of calls was hairy enough to
require multiple dispatches on n.Op, whereas now the logic is uniform
enough that we can easily handle it with a single dispatch.
The downside is handling //go:uintptrescapes is now somewhat clumsy.
(It used to be clumsy, but it still is, too.) The proper fix here is
probably to stop using escape analysis tags for //go:uintptrescapes
and unsafe-uintptr, and have an earlier pass responsible for them.
Finally, note that while we now call fixVariadicCall in Escape, we
still have to call it in Order, because we don't (yet) run Escape on
all compiler-generated functions. In particular, the generated "init"
function for initializing package-level variables can contain calls to
variadic functions and isn't escape analyzed.
Passes toolstash-check -race.
Change-Id: I4cdb92a393ac487910aeee58a5cb8c1500eef881
Reviewed-on: https://go-review.googlesource.com/c/go/+/229759
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Triggers a handful of times in std+cmd.
Change-Id: I9bb8ce9a5f8bae2547cb61157cd8f256e1b63e76
Reviewed-on: https://go-review.googlesource.com/c/go/+/229602
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This CL optimizes code that uses a carry from a function such as
bits.Add64 as the condition in an if statement. For example:
x, c := bits.Add64(a, b, 0)
if c != 0 {
panic("overflow")
}
Rather than converting the carry into a 0 or a 1 value and using
that as an input to a comparison instruction the carry flag is now
used as the input to a conditional branch directly. This typically
removes an ADD LOGICAL WITH CARRY instruction when user code is
doing overflow detection and is closer to the code that a user
would expect to generate.
Change-Id: I950431270955ab72f1b5c6db873b6abe769be0da
Reviewed-on: https://go-review.googlesource.com/c/go/+/219757
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Previously for a method value "x.M", we always flowed x directly to
the heap, which led to the receiver argument generally needing to be
heap allocated.
This CL changes it to flow x to the closure and M's receiver
parameter. This allows receiver arguments to be stack allocated as
long as (1) the closure never escapes, *and* (2) method doesn't leak
its receiver parameter.
Within the standard library, this allows a handful of objects to be
stack allocated instead. Listed here are diagnostics that were
previously emitted by "go build -gcflags=-m std cmd" that are no
longer emitted:
archive/tar/writer.go:118:6: moved to heap: f
archive/tar/writer.go:208:6: moved to heap: f
archive/tar/writer.go:248:6: moved to heap: f
cmd/compile/internal/gc/initorder.go:252:2: moved to heap: d
cmd/compile/internal/gc/initorder.go:75:2: moved to heap: s
cmd/go/internal/generate/generate.go:206:7: &Generator literal escapes to heap
cmd/internal/obj/arm64/asm7.go:910:2: moved to heap: c
cmd/internal/obj/mips/asm0.go:415:2: moved to heap: c
cmd/internal/obj/pcln.go:294:22: new(pcinlineState) escapes to heap
cmd/internal/obj/s390x/asmz.go:459:2: moved to heap: c
crypto/tls/handshake_server.go:56:2: moved to heap: hs
Thanks to Cuong Manh Le for help coming up with this solution.
Fixes#27557.
Change-Id: I8c85d671d07fb9b53e11d2dd05949a34dbbd7e17
Reviewed-on: https://go-review.googlesource.com/c/go/+/228263
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
When generating code for unsigned equals (==) and not equals (!=)
comparisons we currently, on s390x, always use signed comparisons.
This mostly works well, however signed comparisons on s390x sign
extend their immediates and unsigned comparisons zero extend them.
For compare-and-branch instructions which can only have 8-bit
immediates this significantly changes the range of immediate values
we can represent: [-128, 127] for signed comparisons and [0, 255]
for unsigned comparisons.
When generating equals and not equals checks we don't neet to worry
about whether the comparison is signed or unsigned. This CL
therefore adds rules to allow us to switch signedness for such
comparisons if it means that it brings a constant into range for an
8-bit immediate.
For example, a signed equals with an integer in the range [128, 255]
will now be implemented using an unsigned compare-and-branch
instruction rather than separate compare and branch instructions.
As part of this change I've also added support for adding a name
to block control values using the same `x:(...)` syntax we use for
value rules.
Triggers 792 times when compiling cmd and std.
Change-Id: I77fa80a128f0a8ce51a2888d1e384bd5e9b61a77
Reviewed-on: https://go-review.googlesource.com/c/go/+/228642
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Thie CL changes cmd/compile/internal/syntax to give the gc half of
the compiler more control over pragma handling, so that it can prepare
better errors, diagnose misuse, and so on. Before, the API between
the two was hard-coded as a uint16. Now it is an interface{}.
This should set us up better for future directives.
In addition to the split, this CL emits a "misplaced compiler directive"
error for any directive that is in a place where it has no effect.
I've certainly been confused in the past by adding comments
that were doing nothing and not realizing it. This should help
avoid that kind of confusion.
The rule, now applied consistently, is that a //go: directive
must appear on a line by itself immediately before the declaration
specifier it means to apply to. See cmd/compile/doc.go for
precise text and test/directive.go for examples.
This may cause some code to stop compiling, but that code
was broken. For example, this code formerly applied the
//go:noinline to f (not c) but now will fail to compile:
//go:noinline
const c = 1
func f() {}
Change-Id: Ieba9b8d90a27cfab25de79d2790a895cefe5296f
Reviewed-on: https://go-review.googlesource.com/c/go/+/228578
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
This optimization works on any integer with exactly one bit set.
This is identical to being a power of two, except in the
most negative number. Use oneBit instead.
The rule now triggers in a few more places in std+cmd,
in packages encoding/asn1, crypto/elliptic, and
vendor/golang.org/x/crypto/cryptobyte.
This change obviates the need for CL 222479
by doing this optimization consistently in the compiler.
Change-Id: I983c6235290fdc634fda5e11b10f1f8ce041272f
Reviewed-on: https://go-review.googlesource.com/c/go/+/229124
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
reflect.Type.Method (and MethodByName) can be used to obtain a
reference of a method by reflection. The linker needs to know
if reflect.Type.Method is called, and retain all exported methods
accordingly. This is handled by the compiler, which marks the
caller of reflect.Type.Method with REFLECTMETHOD attribute. The
current code failed to handle the reflect package itself, so the
method wrapper reflect.Type.Method is not marked. This CL fixes
it.
Fixes#38515.
Change-Id: I12904d23eda664cf1794bc3676152f3218fb762b
Reviewed-on: https://go-review.googlesource.com/c/go/+/228880
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This test started failing at CL 228106 and was fixed by CL 228677.
Fixes#38496
Change-Id: I2dadcd99227347e8d28179039f5f345e728c4595
Reviewed-on: https://go-review.googlesource.com/c/go/+/228698
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Benchmarking suggests that the combo instruction is notably slower,
at least in the places where we measure.
Updates #37955
Change-Id: I829f1975dd6edf38163128ba51d84604055512f4
Reviewed-on: https://go-review.googlesource.com/c/go/+/228157
Run-TryBot: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
When inserting Select0 and Select1 ops we need to ensure that they
live in the same block as their argument. This is because they need
to be scheduled immediately after their argument for register and
flag allocation to work correctly.
Fixes#38356.
Change-Id: Iba384dbe87010f1c7c4ce909f08011e5f1de7fd5
Reviewed-on: https://go-review.googlesource.com/c/go/+/227879
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Consider
switch x:= x.(type) {
case int:
// int stmts
case error:
// error stmts
}
Prior to this change, we lowered this roughly as:
if x, ok := x.(int); ok {
// int stmts
} else if x, ok := x.(error); ok {
// error stmts
}
x, ok := x.(error) is implemented with a call to runtime.assertE2I2 or runtime.assertI2I2.
x, ok := x.(int) generates inline code that checks whether x has type int,
and populates x and ok as appropriate. We then immediately branch again on ok.
The shortcircuit pass in the SSA backend is designed to recognize situations
like this, in which we are immediately branching on a bool value
that we just calculated with a branch.
However, the shortcircuit pass has limitations when the intermediate state has phis.
In this case, the phi value is x (the int).
CL 222923 improved the situation, but many cases are still unhandled.
I have further improvements in progress, which is how I found this particular problem,
but they are expensive, and may or may not see the light of day.
In the common case of a lone concrete type in a type switch case,
it is easier and cheaper to simply lower a different way, roughly:
if _, ok := x.(int); ok {
x := x.(int)
// int stmts
}
Instead of using a type assertion, though, we extract the value of x
from the interface directly.
This removes the need to track x (the int) across the branch on ok,
which removes the phi, which lets the shortcircuit pass do its job.
Benchmarks for encoding/binary show improvements, as well as some
wild swings on the super fast benchmarks (alignment effects?):
name old time/op new time/op delta
ReadSlice1000Int32s-8 5.25µs ± 2% 4.87µs ± 3% -7.11% (p=0.000 n=44+49)
ReadStruct-8 451ns ± 2% 417ns ± 2% -7.39% (p=0.000 n=45+46)
WriteStruct-8 412ns ± 2% 405ns ± 3% -1.58% (p=0.000 n=46+48)
ReadInts-8 296ns ± 8% 275ns ± 3% -7.23% (p=0.000 n=48+50)
WriteInts-8 324ns ± 1% 318ns ± 2% -1.67% (p=0.000 n=44+49)
WriteSlice1000Int32s-8 5.21µs ± 2% 4.92µs ± 1% -5.67% (p=0.000 n=46+44)
PutUint16-8 0.58ns ± 2% 0.59ns ± 2% +0.63% (p=0.000 n=49+49)
PutUint32-8 0.87ns ± 1% 0.58ns ± 1% -33.10% (p=0.000 n=46+44)
PutUint64-8 0.66ns ± 2% 0.87ns ± 2% +33.07% (p=0.000 n=47+48)
LittleEndianPutUint16-8 0.86ns ± 2% 0.87ns ± 2% +0.55% (p=0.003 n=47+50)
LittleEndianPutUint32-8 0.87ns ± 1% 0.87ns ± 1% ~ (p=0.547 n=45+47)
LittleEndianPutUint64-8 0.87ns ± 2% 0.87ns ± 1% ~ (p=0.451 n=46+47)
ReadFloats-8 79.8ns ± 5% 75.9ns ± 2% -4.83% (p=0.000 n=50+47)
WriteFloats-8 89.3ns ± 1% 88.9ns ± 1% -0.48% (p=0.000 n=46+44)
ReadSlice1000Float32s-8 5.51µs ± 1% 4.87µs ± 2% -11.74% (p=0.000 n=47+46)
WriteSlice1000Float32s-8 5.51µs ± 1% 4.93µs ± 1% -10.60% (p=0.000 n=48+47)
PutUvarint32-8 25.9ns ± 2% 24.0ns ± 2% -7.02% (p=0.000 n=48+50)
PutUvarint64-8 75.1ns ± 1% 61.5ns ± 2% -18.12% (p=0.000 n=45+47)
[Geo mean] 57.3ns 54.3ns -5.33%
Despite the rarity of type switches, this generates noticeably smaller binaries.
file before after Δ %
addr2line 4413296 4409200 -4096 -0.093%
api 5982648 5962168 -20480 -0.342%
cgo 4854168 4833688 -20480 -0.422%
compile 19694784 19682560 -12224 -0.062%
cover 5278008 5265720 -12288 -0.233%
doc 4694824 4682536 -12288 -0.262%
fix 3411336 3394952 -16384 -0.480%
link 6721496 6717400 -4096 -0.061%
nm 4371152 4358864 -12288 -0.281%
objdump 4760960 4752768 -8192 -0.172%
pprof 14810820 14790340 -20480 -0.138%
trace 11681076 11668788 -12288 -0.105%
vet 8285464 8244504 -40960 -0.494%
total 115824120 115627576 -196544 -0.170%
Compiler performance is marginally improved (note that go/types has many type switches):
name old alloc/op new alloc/op delta
Template 35.0MB ± 0% 35.0MB ± 0% +0.09% (p=0.008 n=5+5)
Unicode 28.5MB ± 0% 28.5MB ± 0% ~ (p=0.548 n=5+5)
GoTypes 114MB ± 0% 114MB ± 0% -0.76% (p=0.008 n=5+5)
Compiler 541MB ± 0% 541MB ± 0% -0.03% (p=0.008 n=5+5)
SSA 1.17GB ± 0% 1.17GB ± 0% ~ (p=0.841 n=5+5)
Flate 21.9MB ± 0% 21.9MB ± 0% ~ (p=0.421 n=5+5)
GoParser 26.9MB ± 0% 26.9MB ± 0% ~ (p=0.222 n=5+5)
Reflect 74.6MB ± 0% 74.6MB ± 0% ~ (p=1.000 n=5+5)
Tar 32.9MB ± 0% 32.8MB ± 0% ~ (p=0.056 n=5+5)
XML 42.4MB ± 0% 42.1MB ± 0% -0.77% (p=0.008 n=5+5)
[Geo mean] 73.2MB 73.1MB -0.15%
name old allocs/op new allocs/op delta
Template 377k ± 0% 377k ± 0% +0.06% (p=0.008 n=5+5)
Unicode 354k ± 0% 354k ± 0% ~ (p=0.095 n=5+5)
GoTypes 1.31M ± 0% 1.30M ± 0% -0.73% (p=0.008 n=5+5)
Compiler 5.44M ± 0% 5.44M ± 0% -0.04% (p=0.008 n=5+5)
SSA 11.7M ± 0% 11.7M ± 0% ~ (p=1.000 n=5+5)
Flate 239k ± 0% 239k ± 0% ~ (p=1.000 n=5+5)
GoParser 302k ± 0% 302k ± 0% -0.04% (p=0.008 n=5+5)
Reflect 977k ± 0% 977k ± 0% ~ (p=0.690 n=5+5)
Tar 346k ± 0% 346k ± 0% ~ (p=0.889 n=5+5)
XML 431k ± 0% 430k ± 0% -0.25% (p=0.008 n=5+5)
[Geo mean] 806k 806k -0.10%
For packages with many type switches, this considerably shrinks function text size.
Some examples:
file before after Δ %
encoding/binary.s 30726 29504 -1222 -3.977%
go/printer.s 77597 76005 -1592 -2.052%
cmd/vendor/golang.org/x/tools/go/ast/astutil.s 65704 63318 -2386 -3.631%
cmd/vendor/golang.org/x/tools/go/analysis/passes/unreachable.s 8047 7714 -333 -4.138%
Text size regressions are rare.
Change-Id: Ic10982bbb04876250eaa5bfee97990141ae5fc28
Reviewed-on: https://go-review.googlesource.com/c/go/+/228106
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
If -d=ssa/PASS/debug=N is specified (N >= 2) for a rewrite pass
(e.g. lower), when a Value (or Block) is rewritten, print the
Value (or Block) before and after.
For #31915.
Updates #19013.
Change-Id: I80eadd44302ae736bc7daed0ef68529ab7a16776
Reviewed-on: https://go-review.googlesource.com/c/go/+/176718
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Missed as part of CL 221790. It isn't just * and / that can make NaNs.
Update #36400Fixes#38359
Change-Id: I3fa562f772fe03b510793a6dc0cf6189c0c3e652
Reviewed-on: https://go-review.googlesource.com/c/go/+/227860
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This changes the code generated for variable length shift
counts to use isel instead of instructions that set and
read the carry flag.
This reduces the generated code for shifts like this
by 1 instruction and avoids the use of instructions to
set and read the carry flag.
This sequence can be found in strconv with these results
on power9:
Atof64Decimal 71.6ns ± 0% 68.3ns ± 0% -4.61%
Atof64Float 95.3ns ± 0% 90.9ns ± 0% -4.62%
Atof64FloatExp 153ns ± 0% 149ns ± 0% -2.61%
Atof64Big 234ns ± 0% 232ns ± 0% -0.85%
Atof64RandomBits 348ns ± 0% 369ns ± 0% +6.03%
Atof64RandomFloats 262ns ± 0% 262ns ± 0% ~
Atof32Decimal 72.0ns ± 0% 68.2ns ± 0% -5.28%
Atof32Float 92.1ns ± 0% 87.1ns ± 0% -5.43%
Atof32FloatExp 159ns ± 0% 158ns ± 0% -0.63%
Atof32Random 194ns ± 0% 191ns ± 0% -1.55%
Some tests in codegen/shift.go are enabled to verify the
expected instructions are generated.
Change-Id: I968715d10ada405a8c46132bf19b8ed9b85796d1
Reviewed-on: https://go-review.googlesource.com/c/go/+/227337
Run-TryBot: Lynn Boger <laboger@linux.vnet.ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This removes all files that are only used on darwin/arm and cleans up
build tags in files that are still used on other platforms.
Updates #37611.
Change-Id: Ic9490cf0edfc157c6276a7ca950c1768b34a998f
Reviewed-on: https://go-review.googlesource.com/c/go/+/227197
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
I took some of the infrastructure from Austin's lock logging CR
https://go-review.googlesource.com/c/go/+/192704 (with deadlock
detection from the logs), and developed a setup to give static lock
ranking for runtime locks.
Static lock ranking establishes a documented total ordering among locks,
and then reports an error if the total order is violated. This can
happen if a deadlock happens (by acquiring a sequence of locks in
different orders), or if just one side of a possible deadlock happens.
Lock ordering deadlocks cannot happen as long as the lock ordering is
followed.
Along the way, I found a deadlock involving the new timer code, which Ian fixed
via https://go-review.googlesource.com/c/go/+/207348, as well as two other
potential deadlocks.
See the constants at the top of runtime/lockrank.go to show the static
lock ranking that I ended up with, along with some comments. This is
great documentation of the current intended lock ordering when acquiring
multiple locks in the runtime.
I also added an array lockPartialOrder[] which shows and enforces the
current partial ordering among locks (which is embedded within the total
ordering). This is more specific about the dependencies among locks.
I don't try to check the ranking within a lock class with multiple locks
that can be acquired at the same time (i.e. check the ranking when
multiple hchan locks are acquired).
Currently, I am doing a lockInit() call to set the lock rank of most
locks. Any lock that is not otherwise initialized is assumed to be a
leaf lock (a very high rank lock), so that eliminates the need to do
anything for a bunch of locks (including all architecture-dependent
locks). For two locks, root.lock and notifyList.lock (only in the
runtime/sema.go file), it is not as easy to do lock initialization, so
instead, I am passing the lock rank with the lock calls.
For Windows compilation, I needed to increase the StackGuard size from
896 to 928 because of the new lock-rank checking functions.
Checking of the static lock ranking is enabled by setting
GOEXPERIMENT=staticlockranking before doing a run.
To make sure that the static lock ranking code has no overhead in memory
or CPU when not enabled by GOEXPERIMENT, I changed 'go build/install' so
that it defines a build tag (with the same name) whenever any experiment
has been baked into the toolchain (by checking Expstring()). This allows
me to avoid increasing the size of the 'mutex' type when static lock
ranking is not enabled.
Fixes#38029
Change-Id: I154217ff307c47051f8dae9c2a03b53081acd83a
Reviewed-on: https://go-review.googlesource.com/c/go/+/207619
Reviewed-by: Dan Scales <danscales@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Extend CL 220417 (which removed the integer Greater and Geq ops) to
floating point comparisons. Greater and Geq can always be
implemented using Less and Leq.
Fixes#37316.
Change-Id: Ieaddb4877dd0ff9037a1dd11d0a9a9e45ced71e7
Reviewed-on: https://go-review.googlesource.com/c/go/+/222397
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Before using some CPU instructions, we must check for their presence.
We use global variables in the runtime package to record features.
Prior to this CL, we issued a regular memory load for these features.
The downside to this is that, because it is a regular memory load,
it cannot be hoisted out of loops or otherwise reordered with other loads.
This CL introduces a new intrinsic just for checking cpu features.
It still ends up resulting in a memory load, but that memory load can
now be floated to the entry block and rematerialized as needed.
One downside is that the regular load could be combined with the comparison
into a CMPBconstload+NE. This new intrinsic cannot; it generates MOVB+TESTB+NE.
(It is possible that MOVBQZX+TESTQ+NE would be better.)
This CL does only amd64. It is easy to extend to other architectures.
For the benchmark in #36196, on my machine, this offers a mild speedup.
name old time/op new time/op delta
FMA-8 1.39ns ± 6% 1.29ns ± 9% -7.19% (p=0.000 n=97+96)
NonFMA-8 2.03ns ±11% 2.04ns ±12% ~ (p=0.618 n=99+98)
Updates #15808
Updates #36196
Change-Id: I75e2fcfcf5a6df1bdb80657a7143bed69fca6deb
Reviewed-on: https://go-review.googlesource.com/c/go/+/212360
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
We still disallow inlining for an immediately-recursive function, but allow
inlining if a function is in a recursion chain.
If all functions in the recursion chain are simple, then we could inline
forever down the recursion chain (eventually running out of stack on the
compiler), so we add a map to keep track of the functions we have
already inlined at a call site. We stop inlining when we reach a
function that we have already inlined in the recursive chain. Of course,
normally the inlining will have stopped earlier, because of the cost
function.
We could also limit the depth of inlining by a simple count (say, limit
max inlining of 10 at any given site). Would that limit other
opportunities too much?
Added a test in test/inline.go. runtime.BenchmarkStackCopyNoCache() is
also already a good test that triggers the check to stop inlining
when we reach the start of the recursive chain again.
For the bent benchmark suite, the performance improvement was mostly not
statistically significant, but the geomean averaged out to: -0.68%. The text size
increase was less than .1% for all bent benchmarks. The cmd/go text size increase
was 0.02% and the cmd/compile text size increase was .1%.
Fixes#29737
Change-Id: I892fa84bb07a947b3125ec8f25ed0e508bf2bdf5
Reviewed-on: https://go-review.googlesource.com/c/go/+/226818
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
If slice cap is not set, it will be equal to slice len. So
isSmallMakeSlice only needs to check whether slice cap is constant.
While at it, also add test to make sure panicmakeslicecap is called
when make slice contains invalid non-constant len.
For this benchmark:
func BenchmarkMakeSliceNonConstantLen(b *testing.B) {
len := 1
for i := 0; i < b.N; i++ {
s := make([]int, len, 2)
_ = s
}
}
Result compare with parent:
name old time/op new time/op delta
MakeSliceNonConstantLen-12 18.4ns ± 1% 0.2ns ± 2% -98.66% (p=0.008 n=5+5)
Fixes#37975
Change-Id: I4bc926361bc2ffeab4cfaa888ef0a30cbc3b80e8
Reviewed-on: https://go-review.googlesource.com/c/go/+/226278
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
In CL 187657, I refactored constant conversion logic without realizing
that conversions between int/float and complex types are allowed for
constants (assuming the constant values are representable by the
destination type), but are never allowed for non-constant expressions.
This CL expands convertop to take an extra srcConstant parameter to
indicate whether the source expression is a constant; and if so, to
allow any numeric-to-numeric conversion. (Conversions of values that
cannot be represented in the destination type are rejected by
evconst.)
Fixes#38117.
Change-Id: Id7077d749a14c8fd910be38da170fa5254819f2b
Reviewed-on: https://go-review.googlesource.com/c/go/+/226197
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Make sure we don't use the rewrite ptr + (c + x) -> c + (ptr + x), as
that may create an ephemeral out-of-bounds pointer.
I have not seen an actual bug caused by this yet, but we've seen
them in the 386 port so I'm fixing this issue for amd64 as well.
The load-combining rules needed to be reworked somewhat to still
work without the above broken rule.
Update #37881
Change-Id: I8046d170e89e2035195f261535e34ca7d8aca68a
Reviewed-on: https://go-review.googlesource.com/c/go/+/226437
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Retrying CL 222782, with a fix that will hopefully stop the random crashing.
The issue with the previous CL is that it does pointer arithmetic
in a way that may briefly generate an out-of-bounds pointer. If an
interrupt happens to occur in that state, the referenced object may
be collected incorrectly.
Suppose there was code that did s[x+c]. The previous CL had a rule
to the effect of ptr + (x + c) -> c + (ptr + x). But ptr+x is not
guaranteed to point to the same object as ptr. In contrast,
ptr+(x+c) is guaranteed to point to the same object as ptr, because
we would have already checked that x+c is in bounds.
For example, strconv.trim used to have this code:
MOVZX -0x1(BX)(DX*1), BP
CMPL $0x30, AL
After CL 222782, it had this code:
LEAL 0(BX)(DX*1), BP
CMPB $0x30, -0x1(BP)
An interrupt between those last two instructions could see BP pointing
outside the backing store of the slice involved.
It's really hard to actually demonstrate a bug. First, you need to
have an interrupt occur at exactly the right time. Then, there must
be no other pointers to the object in question. Since the interrupted
frame will be scanned conservatively, there can't even be a dead
pointer in another register or on the stack. (In the example above,
a bug can't happen because BX still holds the original pointer.)
Then, the object in question needs to be collected (or at least
scanned?) before the interrupted code continues.
This CL needs to handle load combining somewhat differently than CL 222782
because of the new restriction on arithmetic. That's the only real
difference (other than removing the bad rules) from that old CL.
This bug is also present in the amd64 rewrite rules, and we haven't
seen any crashing as a result. I will fix up that code similarly to
this one in a separate CL.
Update #37881
Change-Id: I5f0d584d9bef4696bfe89a61ef0a27c8d507329f
Reviewed-on: https://go-review.googlesource.com/c/go/+/225798
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The "runindir" tests used "go run", but relied on relative imports
(which are not supported by "go run" in module mode). Instead, such
tests must use fully-qualified imports, which require either a go.mod
file (in module mode) or that the package be in an appropriate
subdirectory of GOPATH/src (in GOPATH mode).
To set up such a directory, we use yet another copy of the same
overlayDir function currently found in the misc subdirectory of this
repository.
Fixes#33912
Updates #30228
Change-Id: If3d7ea2f7942ba496d98aaaf24a90bcdcf4df9f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/225205
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The load and test instructions compare the given value
against zero and will produce a condition code indicating
one of the following scenarios:
0: Result is zero
1: Result is less than zero
2: Result is greater than zero
3: Result is not a number (NaN)
The instruction can be used to simplify floating point comparisons
against zero, which can enable further optimizations.
This CL also reduces the size of .text section of math.test binary by around
0.7 KB (in hexadecimal, from 1358f0 to 135620).
Change-Id: I33cb714f0c6feebac7a1c46dfcc735e7daceff9c
Reviewed-on: https://go-review.googlesource.com/c/go/+/209159
Reviewed-by: Michael Munday <mike.munday@ibm.com>
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
riscv64 now has atomic intrinsics, so re-enable the atomic intrinsic tests.
Fixes#36765
Change-Id: I838f27570a94d7fa5774c43f1ca5f4df2ca104cf
Reviewed-on: https://go-review.googlesource.com/c/go/+/223560
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This reverts commit CL 222782.
Reason for revert: Reverting to see if 386 errors go away
Update #37881
Change-Id: I74f287404c52414db1b6ff1649effa4ed9e5cc0c
Reviewed-on: https://go-review.googlesource.com/c/go/+/225218
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Rolling back portions of CL 222782 to see if that helps
issue #37881 any.
Update #37881
Change-Id: I9cc3ff8c469fa5e4b22daec715d04148033f46f7
Reviewed-on: https://go-review.googlesource.com/c/go/+/224837
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Batch files should use CRLF endings. LF endings mostly
work but in some situations they cause random errors like
goto commands failing for mysterious reasons. See
golang.org/issue/37791 for more information.
Next CL triggered one of such bug (a label was not being
recognized), so prepare for it by converting to CRLF.
This CL also touches all existing batch files to force git
to update the line endings (unfortunately, changing
.gitattributes only has effect next time the file is checked
out or modified).
Fixes#37791
Updates #9281
Change-Id: I6f9a114351cb7ac9881914400aa210c930eb8cc1
Reviewed-on: https://go-review.googlesource.com/c/go/+/96495
Run-TryBot: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
This commit extends the -spectre flag to cmd/asm and adds
a new Spectre mitigation mode "ret", which enables the use
of retpolines.
Retpolines prevent speculation about the target of an indirect
jump or call and are described in more detail here:
https://support.google.com/faqs/answer/7625886
Change-Id: I4f2cb982fa94e44d91e49bd98974fd125619c93a
Reviewed-on: https://go-review.googlesource.com/c/go/+/222661
Reviewed-by: Keith Randall <khr@golang.org>
This commit adds a new cmd/compile flag -spectre,
which accepts a comma-separated list of possible
Spectre mitigations to apply, or the empty string (none),
or "all". The only known mitigation right now is "index",
which uses conditional moves to ensure that x86-64 CPUs
do not speculate past index bounds checks.
Speculating past index bounds checks may be problematic
on systems running privileged servers that accept requests
from untrusted users who can execute their own programs
on the same machine. (And some more constraints that
make it even more unlikely in practice.)
The cases this protects against are analogous to the ones
Microsoft explains in the "Array out of bounds load/store feeding ..."
sections here:
https://docs.microsoft.com/en-us/cpp/security/developer-guidance-speculative-execution?view=vs-2019#array-out-of-bounds-load-feeding-an-indirect-branch
Change-Id: Ib7532d7e12466b17e04c4e2075c2a456dc98f610
Reviewed-on: https://go-review.googlesource.com/c/go/+/222660
Reviewed-by: Keith Randall <khr@golang.org>
//line bogo.go:9999999 will cause 'go tool objdump' to crash
unless bogo.go has that many lines. Guard the array index
and return innocuous values (nil, nil) from the file cache.
Fixes#36683
Change-Id: I4a9f8444dc611654d270cc876e8848dfd2f84770
Reviewed-on: https://go-review.googlesource.com/c/go/+/223081
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
With a clean cache on a laptop
before change
time go run run.go -- . fixedbugs
real 2m10.195s
user 3m16.547s
sys 1m52.939s
Or, before, directly after make.bash (the actual use case we care about)
time go run run.go -- . fixedbugs
real 2m8.704s
user 3m12.327s
sys 1m49.123s
after change
time go run run.go -- . fixedbugs
real 1m38.915s
user 2m38.389s
sys 1m8.490s
Tests, fortunately, still seem to pass.
Latest version of this takes the slow route for cross-compilation, which includes wasm.
Change-Id: Iad19951612defa96c4e9830bce920c5e8733834a
Reviewed-on: https://go-review.googlesource.com/c/go/+/223083
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The default is for later flags to override earlier ones,
so if the asmcheck set flags, it lost the important -S=2.
Change-Id: Id538254908d658da2acb55157ac4f6fa44f6a467
Reviewed-on: https://go-review.googlesource.com/c/go/+/222820
Reviewed-by: Keith Randall <khr@golang.org>
If typehash (used by reflect) does not match the built-in map's hash,
then problems occur. If a map is built using reflect, and then
assigned to a variable of map type, the hash function can change. That
causes very bad things.
This issue is rare. MapOf consults a cache of all types that occur in
the binary before making a new one. To make a true new map type (with
a hash function derived from typehash) that map type must not occur in
the binary anywhere. But to cause the bug, we need a variable of that
type in order to assign to it. The only way to make that work is to
use a named map type for the variable, so it is distinct from the
unnamed version that MapOf looks for.
Fixes#37716
Change-Id: I3537bfceca8cbfa1af84202f432f3c06953fe0ed
Reviewed-on: https://go-review.googlesource.com/c/go/+/222357
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Use a separate compiler pass to introduce complicated x86 addressing
modes. Loads in the normal architecture rules (for x86 and all other
platforms) can have constant offsets (AuxInt values) and symbols (Aux
values), but no more.
The complex addressing modes (x+y, x+2*y, etc.) are introduced in a
separate pass that combines loads with LEAQx ops.
Organizing rewrites this way simplifies the number of rewrites
required, as there are lots of different rule orderings that have to
be specified to ensure these complex addressing modes are always found
if they are possible.
Update #36468
Change-Id: I5b4bf7b03a1e731d6dfeb9ef19b376175f3b4b44
Reviewed-on: https://go-review.googlesource.com/c/go/+/217097
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
CL 212777 added a check to isNonNegative
to return true for unsigned values.
However, the SSA backend isn't type safe
enough for that to be sound.
The other checks in isNonNegative
look only at the pattern of bits.
Remove the type-based check.
Updates #37753
Change-Id: I059d0e86353453133f2a160dce53af299f42e533
Reviewed-on: https://go-review.googlesource.com/c/go/+/222620
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
-gcflags=-flag means apply the flags only to the package named
on the command line (the main package, for these tests).
-gcflags=all=-flag means apply the flags to everything in the build,
including the standard library.
cmd/dist uses -gcflags=all=$GO_GCFLAGS, so test/run should do the same,
as the comment already explains, to avoid rebuilding the entire standard
library without the flags during test/run's builds.
We changed the scope of the flags without a pattern a few releases
ago and missed this one.
Change-Id: I039e60ca619d39e5b502261d4a73e1afc7e3f9fc
Reviewed-on: https://go-review.googlesource.com/c/go/+/213827
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This is one of several changes that were part of a larger rewrite
which I made in early 2019 after switching to the new number literal
syntax implementation. The purpose of the rewrite was to simplify
reading of source code (Unicode character by character) and speed up
the scanner but was never submitted for review due to other priorities.
Part 2 of 3:
This change contains improvements to the scanner error messages:
- Use "rune literal" rather than "character literal" to match the
spec nomenclature.
- Shorter, more to the point error messages.
(For instance, "more than one character in rune literal" rather
than "invalid character literal (more than one character)", etc.)
Change-Id: I1aaf79003374a68dbb05926437ed305cf2a8ec96
Reviewed-on: https://go-review.googlesource.com/c/go/+/221602
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
There are still two places in src/runtime/string.go that use
staticbytes, so we cannot delete it just yet.
There is a new codegen test to verify that the index calculation
is constant-folded, at least on amd64. ppc64, mips[64] and s390x
cannot currently do that.
There is also a new runtime benchmark to ensure that this does not
slow down performance (tested against parent commit):
name old time/op new time/op delta
ConvT2EByteSized/bool-4 1.07ns ± 1% 1.07ns ± 1% ~ (p=0.060 n=14+15)
ConvT2EByteSized/uint8-4 1.06ns ± 1% 1.07ns ± 1% ~ (p=0.095 n=14+15)
Updates #37612
Change-Id: I5ec30738edaa48cda78dfab4a78e24a32fa7fd6a
Reviewed-on: https://go-review.googlesource.com/c/go/+/221957
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Trying this CL again, with a fixed test that allows platforms
to disagree on the exact behavior of converting NaNs.
We store 32-bit floating point constants in a 64-bit field, by
converting that 32-bit float to 64-bit float to store it, and convert
it back to use it.
That works for *almost* all floating-point constants. The exception is
signaling NaNs. The round trip described above means we can't represent
a 32-bit signaling NaN, because conversions strip the signaling bit.
To fix this issue, just forbid NaNs as floating-point constants in SSA
form. This shouldn't affect any real-world code, as people seldom
constant-propagate NaNs (except in test code).
Additionally, NaNs are somewhat underspecified (which of the many NaNs
do you get when dividing 0/0?), so when cross-compiling there's a
danger of using the compiler machine's NaN regime for some math, and
the target machine's NaN regime for other math. Better to use the
target machine's NaN regime always.
Update #36400
Change-Id: Idf203b688a15abceabbd66ba290d4e9f63619ecb
Reviewed-on: https://go-review.googlesource.com/c/go/+/221790
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Print the bytes of the instruction that generated a SIGILL.
This should help us respond to bug reports without having to
go back-and-forth with the reporter to get the instruction involved.
Might also help with SIGILL problems that are difficult to reproduce.
Update #37513
Change-Id: I33059b1dbfc97bce16142a843f32a88a6547e280
Reviewed-on: https://go-review.googlesource.com/c/go/+/221431
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Open-coded defers were fixed and re-enabled on riscv64, however this test was
inadvertantly left disabled.
Updates #36786
Change-Id: I128fc84baa3d51f50d173e19e52051dc4d9a07c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/220920
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The existing implementation outputs inline cost iff function cannot be inlined with Debug['m'] > 1, the cost info is also useful if the function is inlineable.
Fixes#36780
Change-Id: Ic96f6baf96aee25fb4b33d31d4d644dc2310e536
Reviewed-on: https://go-review.googlesource.com/c/go/+/216778
Run-TryBot: Alberto Donizetti <alb.donizetti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The generic Greater and Geq ops can always be replaced with the Less and
Leq ops. This CL therefore removes them. This simplifies the compiler since
it reduces the number of operations that need handling in both code and in
rewrite rules. This will be especially true when adding control flow
optimizations such as the integer-in-range optimizations in CL 165998.
Change-Id: If0648b2b19998ac1bddccbf251283f3be4ec3040
Reviewed-on: https://go-review.googlesource.com/c/go/+/220417
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Ensure that any comparison between two values has the same argument
order. This helps ensure that they can be eliminated during the
lowered CSE pass which will be particularly important if we eliminate
the Greater and Geq ops (see #37316).
Example:
CMP R0, R1
BLT L1
CMP R1, R0 // different order, cannot eliminate
BEQ L2
CMP R0, R1
BLT L1
CMP R0, R1 // same order, can eliminate
BEQ L2
This does have some drawbacks. Notably comparisons might 'flip'
direction in the assembly output after even small changes to the
code or compiler. It should help make optimizations more reliable
however.
compilecmp master -> HEAD
master (218f4572f5): text/template: make reflect.Value indirections more robust
HEAD (f1661fef3e): cmd/compile: canonicalize comparison argument order
platform: linux/amd64
file before after Δ %
api 6063927 6068023 +4096 +0.068%
asm 5191757 5183565 -8192 -0.158%
cgo 4893518 4901710 +8192 +0.167%
cover 5330345 5326249 -4096 -0.077%
fix 3417778 3421874 +4096 +0.120%
pprof 14889456 14885360 -4096 -0.028%
test2json 2848138 2844042 -4096 -0.144%
trace 11746239 11733951 -12288 -0.105%
total 132739173 132722789 -16384 -0.012%
Change-Id: I11736b3fe2a4553f6fc65018f475e88217fa22f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/220425
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This reverts CL 213477.
Reason for revert: tests are failing on linux-mips*-rtrk builders.
Change-Id: I8168f7450890233f1bd7e53930b73693c26d4dc0
Reviewed-on: https://go-review.googlesource.com/c/go/+/220897
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
We store 32-bit floating point constants in a 64-bit field, by
converting that 32-bit float to 64-bit float to store it, and convert
it back to use it.
That works for *almost* all floating-point constants. The exception is
signaling NaNs. The round trip described above means we can't represent
a 32-bit signaling NaN, because conversions strip the signaling bit.
To fix this issue, just forbid NaNs as floating-point constants in SSA
form. This shouldn't affect any real-world code, as people seldom
constant-propagate NaNs (except in test code).
Additionally, NaNs are somewhat underspecified (which of the many NaNs
do you get when dividing 0/0?), so when cross-compiling there's a
danger of using the compiler machine's NaN regime for some math, and
the target machine's NaN regime for other math. Better to use the
target machine's NaN regime always.
This has been a bug since 1.10, and there's an easy workaround
(declare a global varaible containing the signaling NaN pattern, and
use that as the argument to math.Float32frombits) so we'll fix it in
1.15.
Fixes#36400
Update #36399
Change-Id: Icf155e743281560eda2eed953d19a829552ccfda
Reviewed-on: https://go-review.googlesource.com/c/go/+/213477
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
The address calculations in the example end up doing x << 4 + y + 0.
Before this CL we use a SHLQ+LEAQ. Since the constant offset is 0,
we can use SHLQ+ADDQ instead.
Change-Id: Ia048c4fdbb3a42121c7e1ab707961062e8247fca
Reviewed-on: https://go-review.googlesource.com/c/go/+/209959
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The wrapper takes a pointer to the argument, not the argument itself.
Fixes#36705
Change-Id: I566d4457d00bf5b84e4a8315a26516975f0d7e10
Reviewed-on: https://go-review.googlesource.com/c/go/+/215942
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
We should panic in this situation. Rewriting to a SSA op just leads
to a compiler panic.
Fixes#36259
Change-Id: I6e0bccbed7dd0fdac7ebae76b98a211947947386
Reviewed-on: https://go-review.googlesource.com/c/go/+/212405
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
• Inline check function because it's more readable.
• Delete toolPath because it was unused.
• Use strings.TrimPrefix because it's simpler.
• Remove out variable because its value was unused.
• Rename serr to err because it's more consistent.
Change-Id: I084fb4f8b399578834d5eea29a673c386cf3a357
Reviewed-on: https://go-review.googlesource.com/c/go/+/218701
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Hajime Hoshi <hajimehoshi@gmail.com>
The error message is now positioned at the statement position (which is
an identifing token, such as the '=' for assignments); and in case of
assignments it emphasizes the assignment by putting the Lhs and Rhs
in parentheses. Finally, the wording is changed from "use of * as value"
to the stronger "cannot use * as value" (for which there is precedent
elsewhere in the parser).
Fixes#36858.
Change-Id: Ic3f101bba50f58e3a1d9b29645066634631f2d61
Reviewed-on: https://go-review.googlesource.com/c/go/+/218337
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Brad's battery died on a plane and the file stayed open for 8 years
without anyone noticing. 😄
Someone noticed in https://github.com/gopherjs/gopherjs/pull/950.
Updates #2833
Change-Id: I46b28ac014a8c355be94e026615f119f96e5d51a
Reviewed-on: https://go-review.googlesource.com/c/go/+/218700
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
The R_CALLRISCV relocation marker is on the JALR instruction, however the actual
relocation is currently two instructions previous for the AUIPC+ADDI sequence.
Adjust the platform dependent offset accordingly and re-enable open-coded defers.
Fixes#36786.
Change-Id: I71597c193c447930fbe94ce44b7355e89ae877bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/216797
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This test expects that open-coded defers are enabled, which is not currently
the case on riscv64.
Updates issue #27532 and #36786.
Change-Id: I94bb558c5b0734b4cfe5ae12873be81026009bcf
Reviewed-on: https://go-review.googlesource.com/c/go/+/216777
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Open-coded defers are currently broken on riscv64 - disable them for the
time being. All of the standard package tests now pass on linux/riscv64.
Updates issue #27532 and #36786
Change-Id: I20fc25ce91dfad48be32409ba5c64ca9a6acef1d
Reviewed-on: https://go-review.googlesource.com/c/go/+/216517
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
On PPC64, MOVWload, MOVDload, and MOVDstore are assembled to a
"DS from" instruction which requiers the offset is a multiple of
4. Only fold offset to such instructions if it is a multiple of 4.
Fixes#36723.
"GOARCH=ppc64 GOOS=linux go build -gcflags=all=-d=ssa/check/on std cmd"
passes now.
Change-Id: I67f2a6ac02f0d33d470f68ff54936c289a4c765b
Reviewed-on: https://go-review.googlesource.com/c/go/+/216379
Reviewed-by: Carlos Eduardo Seo <cseo@linux.vnet.ibm.com>
This disables some tests that are unsupported on riscv64 and adds support
for risc64 to test/nosplit.
Updates #27532, #36739 and #36765
Change-Id: I0a57797a05bc80236709fc240c0a0efb0ee0d16b
Reviewed-on: https://go-review.googlesource.com/c/go/+/216263
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
CL 214679 added a -race test which shouldn't be run when cgo is not
enabled.
Fixes the nocgo builder.
Change-Id: Iceddf802c4ef6c0de2c3a968e86342303d2d27d8
Reviewed-on: https://go-review.googlesource.com/c/go/+/215477
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This avoids the security problem in #29312 where two very deep, but
distinct, types are given the same name. They both make it to the
linker which chooses one, and the use of the other is now type unsafe.
Instead, give every very deep type its own name. This errs on the
other side, in that very deep types that should be convertible to each
other might now not be. But at least that's not a security hole.
Update #29312.
Change-Id: Iac0ebe73fdc50594fd6fbf7432eef65f9a053126
Reviewed-on: https://go-review.googlesource.com/c/go/+/213517
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
The gccgo compiler did not generate type descriptor for a pointer
to a type alias defined in another package, causing linking error.
The fix is CL 210787. This CL adds a test.
Updates #36085.
Change-Id: I3237c7fedb4d92fb2dc610ee2b88087f96dc2a1a
Reviewed-on: https://go-review.googlesource.com/c/go/+/210858
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
This test was recently added in CL 209961.
Apparently Windows can't seek a directory filehandle?
And move the test from test/fixedbugs (which is mostly for compiler bugs) to
an os package test.
Updates #36019
Change-Id: I626b69b0294471014901d0ccfeefe5e2c7651788
Reviewed-on: https://go-review.googlesource.com/c/go/+/210283
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The first Readdirnames calls opendir and caches the result.
The behavior of that cached opendir result isn't specified on a seek
of the underlying fd. Free the opendir result on a seek so that
we'll allocate a new one the next time around.
Also fix wasm behavior in this regard, so that a seek to the
file start resets the Readdirnames position, regardless of platform.
p.s. I hate the Readdirnames API.
Fixes#35767.
Change-Id: Ieffb61b3c5cdd42591f69ab13f932003966f2297
Reviewed-on: https://go-review.googlesource.com/c/go/+/209961
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The fix for #35652 did not guarantee that it was using a non-empty
src position to replace an empty one. The new code checks again
and falls back to a more certain position. (The input in question
compiles to a single empty infinite loop, and none of the actual instructions
had any source position at all. That is a bug, but given the pathology
of this input, not one worth dealing with this late in the release cycle,
if ever.)
Literally:
00000 (5) TEXT "".f(SB), ABIInternal
00001 (5) PCDATA $0, $-2
00002 (5) PCDATA $1, $-2
00003 (5) FUNCDATA $0, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
00004 (5) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
00005 (5) FUNCDATA $2, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
b2
00006 (?) XCHGL AX, AX
b6
00007 (+1048575) JMP 6
00008 (?) END
TODO: Add runtime.InfiniteLoop(), replace infinite loops with a call to
that, and use an eco-friendly runtime.gopark instead. (This was Cherry's
excellent idea.)
Updates #35652Fixes#35695
Change-Id: I4b9a841142ee4df0f6b10863cfa0721a7e13b437
Reviewed-on: https://go-review.googlesource.com/c/go/+/207964
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
The old recipe for making an infinite loop not be infinite
in the debugger could create an instruction (Prog) with a
line number not tied to any file (index == 0). This caused
downstream failures in DWARF processing.
So don't do that. Also adds a test, also adds a check+panic
to ensure that the next time this happens the error is less
mystifying.
Fixes#35652
Change-Id: I04f30bc94fdc4aef20dd9130561303ff84fd945e
Reviewed-on: https://go-review.googlesource.com/c/go/+/207613
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This reverts CL 207477, restoring CL 207352 with a fix for the
regression observed in the Windows builders.
cmd/compile evidently does not fully support NUL as an output on
Windows, so this time we write ignored 'compile' outputs
to temporary files (instead of os.DevNull as in CL 207352).
Updates #28387Fixes#35619
Change-Id: I2edc5727c3738fa1bccb4b74e50d114cf2a7fcff
Reviewed-on: https://go-review.googlesource.com/c/go/+/207602
Run-TryBot: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This allows maphash.Hash to be allocated on the stack for typical uses.
Fixes#35636
Change-Id: I8366507d26ea717f47a9fb46d3bd69ba799845ac
Reviewed-on: https://go-review.googlesource.com/c/go/+/207444
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This CL detects infinite loops due to negative dereference cycles
during escape analysis, and terminates the loop gracefully. We still
fail to print a complete explanation of the escape path, but esc.go
didn't print *any* explanation for these test cases, so the release
blocking issue here is simply that we don't infinite loop.
Updates #35518.
Change-Id: I39beed036e5a685706248852f1fa619af3b7abbc
Reviewed-on: https://go-review.googlesource.com/c/go/+/206619
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Unlike function calls, when processing instructions that directly
fault we must not subtract 1 from the pc before looking up the
file/line information.
Since the file/line lookup unconditionally subtracts 1, add 1 to
the faulting instruction PCs to compensate.
Fixes#34123
Change-Id: Ie7361e3d2f84a0d4f48d97e5a9e74f6291ba7a8b
Reviewed-on: https://go-review.googlesource.com/c/go/+/196962
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
This API was added for #25819, where it was discussed as math.FMA.
The commit adding it used math.Fma, presumably for consistency
with the rest of the unusual names in package math
(Sincos, Acosh, Erfcinv, Float32bits, etc).
I believe that using an idiomatic Go name is more important here
than consistency with these other names, most of which are historical
baggage from C's standard library.
Early additions like Float32frombits happened before "uppercase for export"
(so they were originally like "float32frombits") and they were not properly
reconsidered when we uppercased the symbols to export them.
That's a mistake we live with.
The names of functions we have added since then, and even a few
that were legacy, are more properly Go-cased, such as IsNaN, IsInf,
and RoundToEven, rather than Isnan, Isinf, and Roundtoeven.
And also constants like MaxFloat32.
For new API, we should keep using proper Go-cased symbols
instead of minimally-upper-cased-C symbols.
So math.FMA, not math.Fma.
This API has not yet been released, so this change does not break
the compatibility promise.
This CL also modifies cmd/compile, since the compiler knows
the name of the function. I could have stopped at changing the
string constants, but it seemed to make more sense to use a
consistent casing everywhere.
Change-Id: I0f6f3407f41e99bfa8239467345c33945088896e
Reviewed-on: https://go-review.googlesource.com/c/go/+/205317
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
We seem to lack any tests for some corner cases of itab.init
(multiple methods with the same name, breaking itab.init doesn't
seem to fail any tests). We also lack tests that fix text of panics.
Add more tests for itab.init.
Change-Id: Id6b536179ba6b0d45c3cb9dc1c66b9311d0ab85e
Reviewed-on: https://go-review.googlesource.com/c/go/+/202451
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
In the dev.link branch we implemented the new object file format
and (part of) the linker improvements described in
https://golang.org/s/better-linker
The new object file is index-based and provides random access.
The linker maps the object files into read-only memory, and
access symbols on-demand using indices, as opposed to reading
all object files sequentially into the heap with the old format.
The linker carries symbol informations using indices (as opposed
to Symbol data structure). Symbols are created after the
reachability analysis, and only created for reachable symbols.
This reduces the linker's memory usage.
Linking cmd/compile, it creates ~25% fewer Symbols, and reduces
memory usage (inuse_space) by ~15%. (More results from Than.)
Currently, both the old and new object file formats are supported.
The old format is used by default. The new format can be turned
on by using the compiler/assembler/linker's -newobj flag. Note
that the flag needs to be specified consistently to all
compilations, i.e.
go build -gcflags=all=-newobj -asmflags=all=-newobj -ldflags=-newobj
Change-Id: Ia0e35306b5b9b5b19fdc7fa7c602d4ce36fa6abd
The logic for keeping arguments alive for calls to //go:uintptrescapes
functions was only applying to direct function calls. This CL changes
it to also apply to direct method calls, which should address most
uses of Proc.Call and LazyProc.Call.
It's still an open question (#34684) whether other call forms (e.g.,
method expressions, or indirect calls via function values, method
values, or interfaces).
Fixes#34474.
Change-Id: I874f97145972b0e237a4c9e8926156298f4d6ce0
Reviewed-on: https://go-review.googlesource.com/c/go/+/198043
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
CL 200958 adds skipping empty init function feature without any tests
for it. A codegen test sounds ideal, but it's unlikely that we can make
one for now, so use a program to manipulate runtime/proc.go:initTask
directly.
Updates #34869
Change-Id: I2683b9a1ace36af6861af02a3a9fb18b3110b282
Reviewed-on: https://go-review.googlesource.com/c/go/+/204217
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
When we do a successful recover of a panic, we resume normal execution by
returning from the frame that had the deferred call that did the recover (after
executing any remaining deferred calls in that frame).
However, suppose we have called runtime.Goexit and there is a panic during one of the
deferred calls run by the Goexit. Further assume that there is a deferred call in
the frame of the Goexit or a parent frame that does a recover. Then the recovery
process will actually resume normal execution above the Goexit frame and hence
abort the Goexit. We will not terminate the thread as expected, but continue
running in the frame above the Goexit.
To fix this, we explicitly create a _panic object for a Goexit call. We then
change the "abort" behavior for Goexits, but not panics. After a recovery, if the
top-level panic is actually a Goexit that is marked to be aborted, then we return
to the Goexit defer-processing loop, so that the Goexit is not actually aborted.
Actual code changes are just panic.go, runtime2.go, and funcid.go. Adjusted the
test related to the new Goexit behavior (TestRecoverBeforePanicAfterGoexit) and
added several new tests of aborted panics (whose behavior has not changed).
Fixes#29226
Change-Id: Ib13cb0074f5acc2567a28db7ca6912cfc47eecb5
Reviewed-on: https://go-review.googlesource.com/c/go/+/200081
Run-TryBot: Dan Scales <danscales@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
"declared and not used" is technically correct, but might confuse
the user. Switching "and" to "but" will hopefully create the
contrast for the users: they did one thing (declaration), but
not the other --- actually using the variable.
This new message is still not ideal (specifically, declared is not
entirely precise here), but at least it matches the other parsers
and is one step in the right direction.
Change-Id: I725c7c663535f9ab9725c4b0bf35b4fa74b0eb20
Reviewed-on: https://go-review.googlesource.com/c/go/+/203282
Run-TryBot: Minux Ma <minux@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Updates #35157 (the bug there was fixed by CL200861)
Change-Id: I67069207b4cdc2ad4a475dd0bbc8555ecc5f534f
Reviewed-on: https://go-review.googlesource.com/c/go/+/203598
Run-TryBot: Giovanni Bajo <rasky@develer.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alberto Donizetti <alb.donizetti@gmail.com>
Generate inline code at defer time to save the args of defer calls to unique
(autotmp) stack slots, and generate inline code at exit time to check which defer
calls were made and make the associated function/method/interface calls. We
remember that a particular defer statement was reached by storing in the deferBits
variable (always stored on the stack). At exit time, we check the bits of the
deferBits variable to determine which defer function calls to make (in reverse
order). These low-cost defers are only used for functions where no defers
appear in loops. In addition, we don't do these low-cost defers if there are too
many defer statements or too many exits in a function (to limit code increase).
When a function uses open-coded defers, we produce extra
FUNCDATA_OpenCodedDeferInfo information that specifies the number of defers, and
for each defer, the stack slots where the closure and associated args have been
stored. The funcdata also includes the location of the deferBits variable.
Therefore, for panics, we can use this funcdata to determine exactly which defers
are active, and call the appropriate functions/methods/closures with the correct
arguments for each active defer.
In order to unwind the stack correctly after a recover(), we need to add an extra
code segment to functions with open-coded defers that simply calls deferreturn()
and returns. This segment is not reachable by the normal function, but is returned
to by the runtime during recovery. We set the liveness information of this
deferreturn() to be the same as the liveness at the first function call during the
last defer exit code (so all return values and all stack slots needed by the defer
calls will be live).
I needed to increase the stackguard constant from 880 to 896, because of a small
amount of new code in deferreturn().
The -N flag disables open-coded defers. '-d defer' prints out the kind of defer
being used at each defer statement (heap-allocated, stack-allocated, or
open-coded).
Cost of defer statement [ go test -run NONE -bench BenchmarkDefer$ runtime ]
With normal (stack-allocated) defers only: 35.4 ns/op
With open-coded defers: 5.6 ns/op
Cost of function call alone (remove defer keyword): 4.4 ns/op
Text size increase (including funcdata) for go binary without/with open-coded defers: 0.09%
The average size increase (including funcdata) for only the functions that use
open-coded defers is 1.1%.
The cost of a panic followed by a recover got noticeably slower, since panic
processing now requires a scan of the stack for open-coded defer frames. This scan
is required, even if no frames are using open-coded defers:
Cost of panic and recover [ go test -run NONE -bench BenchmarkPanicRecover runtime ]
Without open-coded defers: 62.0 ns/op
With open-coded defers: 255 ns/op
A CGO Go-to-C-to-Go benchmark got noticeably faster because of open-coded defers:
CGO Go-to-C-to-Go benchmark [cd misc/cgo/test; go test -run NONE -bench BenchmarkCGoCallback ]
Without open-coded defers: 443 ns/op
With open-coded defers: 347 ns/op
Updates #14939 (defer performance)
Updates #34481 (design doc)
Change-Id: I63b1a60d1ebf28126f55ee9fd7ecffe9cb23d1ff
Reviewed-on: https://go-review.googlesource.com/c/go/+/202340
Reviewed-by: Austin Clements <austin@google.com>
This change introduces an arm intrinsic that generates the FMULAD
instruction for the fused-multiply-add operation on systems that
support it. System support is detected via cpu.ARM.HasVFPv4. A rewrite
rule translates the generic intrinsic to FMULAD.
Updates #25819.
Change-Id: I8459e5dd1cdbdca35f88a78dbeb7d387f1e20efa
Reviewed-on: https://go-review.googlesource.com/c/go/+/142117
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
To permit ssa-level optimization, this change introduces an amd64 intrinsic
that generates the VFMADD231SD instruction for the fused-multiply-add
operation on systems that support it. System support is detected via
cpu.X86.HasFMA. A rewrite rule can then translate the generic ssa intrinsic
("Fma") to VFMADD231SD.
The benchmark compares the software implementation (old) with the intrinsic
(new).
name old time/op new time/op delta
Fma-4 27.2ns ± 1% 1.0ns ± 9% -96.48% (p=0.008 n=5+5)
Updates #25819.
Change-Id: I966655e5f96817a5d06dff5942418a3915b09584
Reviewed-on: https://go-review.googlesource.com/c/go/+/137156
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
In order to make math.FMA a compiler intrinsic for ISAs like ARM64,
PPC64[le], and S390X, a generic 3-argument opcode "Fma" is provided and
rewritten as
ARM64: (Fma x y z) -> (FMADDD z x y)
PPC64: (Fma x y z) -> (FMADD x y z)
S390X: (Fma x y z) -> (FMADD z x y)
Updates #25819.
Change-Id: Ie5bc628311e6feeb28ddf9adaa6e702c8c291efa
Reviewed-on: https://go-review.googlesource.com/c/go/+/131959
Run-TryBot: Akhil Indurti <aindurti@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
We need to explicitly convert pointers to unsafe.Pointer before
passing to the runtime checkptr instrumentation in case the user
declared their own type with underlying type unsafe.Pointer.
Updates #22218.
Fixes#34966.
Change-Id: I3baa2809d77f8257167cd78f57156f819130baa8
Reviewed-on: https://go-review.googlesource.com/c/go/+/201782
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Generate inline code at defer time to save the args of defer calls to unique
(autotmp) stack slots, and generate inline code at exit time to check which defer
calls were made and make the associated function/method/interface calls. We
remember that a particular defer statement was reached by storing in the deferBits
variable (always stored on the stack). At exit time, we check the bits of the
deferBits variable to determine which defer function calls to make (in reverse
order). These low-cost defers are only used for functions where no defers
appear in loops. In addition, we don't do these low-cost defers if there are too
many defer statements or too many exits in a function (to limit code increase).
When a function uses open-coded defers, we produce extra
FUNCDATA_OpenCodedDeferInfo information that specifies the number of defers, and
for each defer, the stack slots where the closure and associated args have been
stored. The funcdata also includes the location of the deferBits variable.
Therefore, for panics, we can use this funcdata to determine exactly which defers
are active, and call the appropriate functions/methods/closures with the correct
arguments for each active defer.
In order to unwind the stack correctly after a recover(), we need to add an extra
code segment to functions with open-coded defers that simply calls deferreturn()
and returns. This segment is not reachable by the normal function, but is returned
to by the runtime during recovery. We set the liveness information of this
deferreturn() to be the same as the liveness at the first function call during the
last defer exit code (so all return values and all stack slots needed by the defer
calls will be live).
I needed to increase the stackguard constant from 880 to 896, because of a small
amount of new code in deferreturn().
The -N flag disables open-coded defers. '-d defer' prints out the kind of defer
being used at each defer statement (heap-allocated, stack-allocated, or
open-coded).
Cost of defer statement [ go test -run NONE -bench BenchmarkDefer$ runtime ]
With normal (stack-allocated) defers only: 35.4 ns/op
With open-coded defers: 5.6 ns/op
Cost of function call alone (remove defer keyword): 4.4 ns/op
Text size increase (including funcdata) for go cmd without/with open-coded defers: 0.09%
The average size increase (including funcdata) for only the functions that use
open-coded defers is 1.1%.
The cost of a panic followed by a recover got noticeably slower, since panic
processing now requires a scan of the stack for open-coded defer frames. This scan
is required, even if no frames are using open-coded defers:
Cost of panic and recover [ go test -run NONE -bench BenchmarkPanicRecover runtime ]
Without open-coded defers: 62.0 ns/op
With open-coded defers: 255 ns/op
A CGO Go-to-C-to-Go benchmark got noticeably faster because of open-coded defers:
CGO Go-to-C-to-Go benchmark [cd misc/cgo/test; go test -run NONE -bench BenchmarkCGoCallback ]
Without open-coded defers: 443 ns/op
With open-coded defers: 347 ns/op
Updates #14939 (defer performance)
Updates #34481 (design doc)
Change-Id: I51a389860b9676cfa1b84722f5fb84d3c4ee9e28
Reviewed-on: https://go-review.googlesource.com/c/go/+/190098
Reviewed-by: Austin Clements <austin@google.com>
Switch the default to new object files.
Internal linking cgo is disabled for now, as it does not work yet
in newobj mode.
Shared libraries are also broken.
Disable some tests that are known broken for now.
Change-Id: I8ca74793423861d607a2aa7b0d89a4f4d4ca7671
Reviewed-on: https://go-review.googlesource.com/c/go/+/200161
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
The Go spec requires
If a deferred function value evaluates to nil, execution
panics when the function is invoked, not when the "defer"
statement is executed.
On Wasm and AIX, currently we actually emit a nil check at the
point of defer statement, which will make it panic too early.
This CL fixes this.
Also, on Wasm, now the nil function will be passed through
deferreturn to jmpdefer, which does an explicit nil check and
calls sigpanic if it is nil. This sigpanic, being called from
assembly, is ABI0. So change the assembler backend to also
handle sigpanic in ABI0.
Fixes#34926.
Updates #8047.
Change-Id: I28489a571cee36d2aef041f917b8cfdc31d557d4
Reviewed-on: https://go-review.googlesource.com/c/go/+/201297
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
When a subsequent load/store of a ptr makes the nil check of that pointer
unnecessary, if their lines differ, change the line of the load/store
to that of the nilcheck, and attempt to rehome the load/store position
instead.
This fix makes profiling less accurate in order to make panics more
informative.
Fixes#33724
Change-Id: Ib9afaac12fe0d0320aea1bf493617facc34034b3
Reviewed-on: https://go-review.googlesource.com/c/go/+/200197
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Add to the testcase originally created for issue 34577 so
as to also trigger the error condition for issue 34852 (the
two bugs are closely related).
Updates #34577.
Updates #34852.
Change-Id: I2347369652ce500184347606b2bb3e76d802b204
Reviewed-on: https://go-review.googlesource.com/c/go/+/201017
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
When assessing whether A <= B, the poset's OrderedOrEqual has a passing
condition which permits A <= B, but is not sufficient to infer that A <= B.
This CL removes that incorrect passing condition.
Having identified that A and B are in the poset, the method will report that
A <= B if any of these three conditions are true:
(1) A and B are the same node in the poset.
- This means we know that A == B.
(2) There is a directed path, strict or not, from A -> B
- This means we know that, at least, A <= B, but A < B is possible.
(3) There is a directed path from B -> A, AND that path has no strict edges.
- This means we know that B <= A, but do not know that B < A.
In condition (3), we do not have enough information to say that A <= B, rather
we only know that B == A (which satisfies A <= B) is possible. The way I
understand it, a strict edge shows a known, strictly-ordered relation (<) but
the lack of a strict edge does not show the lack of a strictly-ordered relation.
The difference is highlighted by the example in #34802, where a bounds check is
incorrectly removed by prove, such that negative indexes into a slice
succeed:
n := make([]int, 1)
for i := -1; i <= 0; i++ {
fmt.Printf("i is %d\n", i)
n[i] = 1 // No Bounds check, program runs, assignment to n[-1] succeeds!!
}
When prove is checking the negative/failed branch from the bounds check at n[i],
in the signed domain we learn (0 > i || i >= len(n)). Because prove can't learn
the OR condition, we check whether we know that i is non-negative so we can
learn something, namely that i >= len(n). Prove uses the poset to check whether
we know that i is non-negative. At this point the poset holds the following
relations as a directed graph:
-1 <= i <= 0
-1 < 0
In poset.OrderedOrEqual, we are testing for 0 <= i. In this case, condition (3)
above is true because there is a non-strict path from i -> 0, and that path
does NOT have any strict edges. Because this condition is true, the poset
reports to prove that i is known to be >= 0. Knowing, incorrectly, that i >= 0,
prove learns from the failed bounds check that i >= len(n) in the signed domain.
When the slice, n, was created, prove learned that len(n) == 1. Because i is
also the induction variable for the loop, upon entering the loop, prove previously
learned that i is in [-1,0]. So when prove attempts to learn from the failed
bounds check, it finds the new fact, i > len(n), unsatisfiable given that it
previously learned that i <= 0 and len(n) = 1.
Fixes#34802
Change-Id: I235f4224bef97700c3aa5c01edcc595eb9f13afc
Reviewed-on: https://go-review.googlesource.com/c/go/+/200759
Run-TryBot: Zach Jones <zachj1@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Giovanni Bajo <rasky@develer.com>
Reviewed-by: Keith Randall <khr@golang.org>
Increases the exec timeout from 5sec to 1min, but
also print out the error value on any test failure.
Fixes#34836
Change-Id: Ida2b8bd460243491ef0f90dfe0f978dfe02a0703
Reviewed-on: https://go-review.googlesource.com/c/go/+/200519
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Test case with code that caused a gccgo error while emitting export
data for an inlinable function.
Updates #34577.
Change-Id: I28b598c4c893c77f4a76bb4f2d27e5b42f702992
Reviewed-on: https://go-review.googlesource.com/c/go/+/198057
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
