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>
Based on riscv-go port.
Updates #27532
Change-Id: Ia329daa243db63ff334053b8807ea96b97ce3acf
Reviewed-on: https://go-review.googlesource.com/c/go/+/204631
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Change the type printer to take a map of types that we're currently
printing. When we happen upon a type that we're already in the middle
of printing, print a reference to it instead.
A reference to another type is built using the offset of the first
byte of that type's string representation in the result. To facilitate
that computation (and it's probably more efficient, regardless), we
print the type to a buffer as we go, and build the string at the end.
It would be nice to use string.Builder instead of bytes.Buffer, but
string.Builder wasn't around in Go 1.4, and we'd like to bootstrap
from that version.
Fixes#29312
Change-Id: I49d788c1fa20f770df7b2bae3b9979d990d54803
Reviewed-on: https://go-review.googlesource.com/c/go/+/214239
Reviewed-by: Robert Griesemer <gri@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>
Currently, a block's control instruction gets the liveness info
of the last Value in the block. However, for an empty block, the
control instruction gets the invalid liveness info and therefore
not preemptible. One example is empty infinite loop, which has
only a control instruction. The control instruction being non-
preemptible makes the whole loop non-preemptible.
Fix this by using a different, preemptible liveness info for
empty block's control. We can choose an arbitrary preemptible
liveness info, as at run time we don't really use the liveness
map at that instruction.
As before, if the last Value in the block is non-preemptible, so
is the block control. For example, the conditional branch in the
write barrier test block is still non-preemptible.
Also, only update liveness info if we are actually emitting
instructions. So zero-width Values' liveness info (which are
always invalid) won't affect the block control's liveness info.
For example, if the last Values in a block is a tuple-generating
operation and a Select, the block control instruction is still
preemptible.
Fixes#35923.
Change-Id: Ic5225f3254b07e4955f7905329b544515907642b
Reviewed-on: https://go-review.googlesource.com/c/go/+/209659
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
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 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>
Intrinsify these functions to match other platforms. Update the
sequence of instructions used in the assembly implementations to
match the intrinsics.
Also, add a micro benchmark so we can more easily measure the
performance of these two functions:
name old time/op new time/op delta
And8-8 5.33ns ± 7% 2.55ns ± 8% -52.12% (p=0.000 n=20+20)
And8Parallel-8 7.39ns ± 5% 3.74ns ± 4% -49.34% (p=0.000 n=20+20)
Or8-8 4.84ns ±15% 2.64ns ±11% -45.50% (p=0.000 n=20+20)
Or8Parallel-8 7.27ns ± 3% 3.84ns ± 4% -47.10% (p=0.000 n=19+20)
By using a 'rotate then xor selected bits' instruction combined with
either a 'load and and' or a 'load and or' instruction we can
implement And8 and Or8 with far fewer instructions. Replacing
'compare and swap' with atomic instructions may also improve
performance when there is contention.
Change-Id: I28bb8032052b73ae8ccdf6e4c612d2877085fa01
Reviewed-on: https://go-review.googlesource.com/c/go/+/204277
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Renames variables sizeof_Array and other array_* variables
that were actually intended for slices and not arrays.
Change-Id: I391b95880cc77cabb8472efe694b7dd19545f31a
Reviewed-on: https://go-review.googlesource.com/c/go/+/180919
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This is intended to allow IDEs to note where the optimizer
was not able to improve users' code. There may be other
applications for this, for example in studying effectiveness
of optimizer changes more quickly than running benchmarks,
or in verifying that code changes did not accidentally disable
optimizations in performance-critical code.
Logging of nilcheck (bad) for amd64 is implemented as
proof-of-concept. In general, the intent is that optimizations
that didn't happen are what will be logged, because that is
believed to be what IDE users want.
Added flag -json=version,dest
Check that version=0. (Future compilers will support a
few recent versions, I hope that version is always <=3.)
Dest is expected to be one of:
/path (or \path in Windows)
will create directory /path and fill it w/ json files
file://path
will create directory path, intended either for
I:\dont\know\enough\about\windows\paths
trustme_I_know_what_I_am_doing_probably_testing
Not passing an absolute path name usually leads to
json splattered all over source directories,
or failure when those directories are not writeable.
If you want a foot-gun, you have to ask for it.
The JSON output is directed to subdirectories of dest,
where each subdirectory is net/url.PathEscape of the
package name, and each for each foo.go in the package,
net/url.PathEscape(foo).json is created. The first line
of foo.json contains version and context information,
and subsequent lines contains LSP-conforming JSON
describing the missing optimizations.
Change-Id: Ib83176a53a8c177ee9081aefc5ae05604ccad8a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/204338
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This restores intrinsic status to functions copied from math/bits
into runtime/internal/sys, as an aid to runtime performance.
Updates #35112.
Change-Id: I41a7d87cf00f1e64d82aa95c5b1000bc128de820
Reviewed-on: https://go-review.googlesource.com/c/go/+/206200
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Previously langSupported applied -lang as though it's a global
restriction, but it's actually a per-package restriction. This CL
fixes langSupported to take a *types.Pkg parameter to reflect this and
updates its callers accordingly.
This is relevant for signed shifts (added in Go 1.12), because they
can be inlined into a Go 1.11 package; and for overlapping interfaces
(added in Go 1.13), because they can be exported as part of the
package's API.
Today we require all Go packages to be compiled with the same
toolchain, and all uses of langSupported are for controlling
backwards-compatible features. So we can simply assume that since the
imported packages type-checked successfully, they must have been
compiled with an appropriate -lang setting.
In the future if we ever want to use langSupported to control
backwards-incompatible language changes, we might need to record the
-lang flag used for compiling a package in its export data.
Fixes#35437.
Fixes#35442.
Change-Id: Ifdf6a62ee80cd5fb4366cbf12933152506d1b36e
Reviewed-on: https://go-review.googlesource.com/c/go/+/205977
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Robert Griesemer <gri@golang.org>
This CL also restores analysis details for (1) expressions that are
directly heap allocated because of being too large for the stack or
non-constant in size, and (2) for assignments that we short circuit
because we flow their address to another escaping object.
No change to normal compilation behavior. Only adds additional Printfs
guarded by -m=2.
Updates #31489.
Change-Id: I43682195d389398d75ced2054e29d9907bb966e7
Reviewed-on: https://go-review.googlesource.com/c/go/+/205917
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
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>
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
Flip back to the old object files for Go 1.14.
Change-Id: I4ad499460fb7156b63fc63e9c6ea4f7099e20af2
Reviewed-on: https://go-review.googlesource.com/c/go/+/204098
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Once defined, a stack slot holding an open-coded defer arg should always be marked
live, since it may be used at any time if there is a panic. These stack slots are
typically kept live naturally by the open-defer code inlined at each return/exit point.
However, we need to do extra work to make sure that they are kept live if a
function has an infinite loop or a panic exit.
For this fix, only in the case of a function that is using open-coded defers, we
compute the set of blocks (most often empty) that cannot reach a return or a
BlockExit (panic) because of an infinite loop. Then, for each block b which
cannot reach a return or BlockExit or is a BlockExit block, we mark each defer arg
slot as live, as long as the definition of the defer arg slot dominates block b.
For this change, had to export (*Func).sdom (-> Sdom) and SparseTree.isAncestorEq
(-> IsAncestorEq)
Updates #35277
Change-Id: I7b53c9bd38ba384a3794386dd0eb94e4cbde4eb1
Reviewed-on: https://go-review.googlesource.com/c/go/+/204802
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Introduce a mechanism for marking architecture-specific Ops
unsafe. And mark ones that use REGTMP on ARM64, as for async
preemption we will be using REGTMP as a temporary register in the
injected call.
Change-Id: I8ff22e87d8f9cb10d02a2f0af7c12ad6d7d58f54
Reviewed-on: https://go-review.googlesource.com/c/go/+/203459
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Austin Clements <austin@google.com>
For async preemption, we will be using REGTMP as a temporary
register in injected call on ARM64, which will clobber it. So any
code that uses REGTMP is not safe for async preemption.
For ZeroRange, which is inserted at the function entry where
there is no register live, we could just use a different register
and avoid REGTMP.
Change-Id: I3db763828df6846908c9843a9912597efb9efcdf
Reviewed-on: https://go-review.googlesource.com/c/go/+/203458
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
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>
This CL extends cmd/compile's experimental libFuzzer support with
calls to __sanitizer_cov_trace_{,const_}cmp{1,2,4,8}. This allows much
more efficient fuzzing of comparisons.
Only supports amd64 and arm64 for now.
Updates #14565.
Change-Id: Ibf82a8d9658f2bc50d955bdb1ae26723a3f0584d
Reviewed-on: https://go-review.googlesource.com/c/go/+/203887
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This CL adds experimental coverage instrumentation similar to what
github.com/dvyukov/go-fuzz produces in its -libfuzzer mode. The
coverage can be enabled by compiling with -d=libfuzzer. It's intended
to be used in conjunction with -buildmode=c-archive to produce an ELF
archive (.a) file that can be linked with libFuzzer. See #14565 for
example usage.
The coverage generates a unique 8-bit counter for each basic block in
the original source code, and emits an increment operation. These
counters are then collected into the __libfuzzer_extra_counters ELF
section for use by libFuzzer.
Updates #14565.
Change-Id: I239758cc0ceb9ca1220f2d9d3d23b9e761db9bf1
Reviewed-on: https://go-review.googlesource.com/c/go/+/202117
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This change renames the "round" function to the more appropriately named
"alignUp" which rounds an integer up to the next multiple of a power of
two.
This change also adds the alignDown function, which is almost like
alignUp but rounds down to the previous multiple of a power of two.
With these two functions, we also go and replace manual rounding code
with it where we can.
Change-Id: Ie1487366280484dcb2662972b01b4f7135f72fec
Reviewed-on: https://go-review.googlesource.com/c/go/+/190618
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
This is a rough attempt at restoring -m=2 escape analysis diagnostics
on par with those that were available with esc.go. It's meant to be
simple and non-invasive.
For example, given this random example from bytes/reader.go:
138 func (r *Reader) WriteTo(w io.Writer) (n int64, err error) {
...
143 b := r.s[r.i:]
144 m, err := w.Write(b)
esc.go used to report:
bytes/reader.go:138:7: leaking param content: r
bytes/reader.go:138:7: from r.s (dot of pointer) at bytes/reader.go:143:8
bytes/reader.go:138:7: from b (assigned) at bytes/reader.go:143:4
bytes/reader.go:138:7: from w.Write(b) (parameter to indirect call) at bytes/reader.go:144:19
With this CL, escape.go now reports:
bytes/reader.go:138:7: parameter r leaks to {heap} with derefs=1:
bytes/reader.go:138:7: flow: b = *r:
bytes/reader.go:138:7: from r.s (dot of pointer) at bytes/reader.go:143:8
bytes/reader.go:138:7: from r.s[r.i:] (slice) at bytes/reader.go:143:10
bytes/reader.go:138:7: from b := r.s[r.i:] (assign) at bytes/reader.go:143:4
bytes/reader.go:138:7: flow: {heap} = b:
bytes/reader.go:138:7: from w.Write(b) (call parameter) at bytes/reader.go:144:19
Updates #31489.
Change-Id: I0c2b943a0f9ce6345bfff61e1c635172a9290cbb
Reviewed-on: https://go-review.googlesource.com/c/go/+/196959
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: David Chase <drchase@google.com>
Currently, the compiler fails to mark any unsafe-points in the initial
instructions of a function as unsafe points. This happens because
unsafe points are encoded as a stack map index of -2 and the compiler
emits PCDATA instructions when there's a change in the stack map
index, but I had set the initial stack map index to -2. The actual
initial PCDATA value assumed by the PCDATA encoder and the runtime is
-1. Hence, if the first instructions had a stack map index of -2, no
PCDATA was emitted, which cause the runtime to assume the index was -1
instead.
This was particularly problematic in the runtime, where the compiler
was supposed to mark only calls as safe-points and everything else as
unsafe-points. Runtime leaf functions, for example, should have been
marked as entirely unsafe-points, but were instead marked entirely as
safe-points.
Fix this by making the PCDATA instruction generator assume the initial
PCDATA value is -1 instead of -2, so it will emit a PCDATA instruction
right away if the first real instruction is an unsafe-point.
This increases the size of the cmd/go binary by 0.02% since we now
emit slightly more PCDATA than before.
For #10958, #24543.
Change-Id: I92222107f799130072b36d49098d2686f1543699
Reviewed-on: https://go-review.googlesource.com/c/go/+/202084
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
In CL 204617, I intend to make "bound" parameter to have special meaning
in typecheckarraylit, so we can distinguish between type-checks array
literal and slice literal. But we end up with other solution. The CL was
submitted without reverting the "bound" parameter in case of slice
literal.
Technically, it's not harmful, but causes the code harder to read and maintain.
Change-Id: Ia522ccc9a6b8e25d7eaad4aa4957cb4fa18edc60
Reviewed-on: https://go-review.googlesource.com/c/go/+/204618
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Number literal strings returned by the lexer (internal/syntax package) and other
arguments to SetString never contain leading whitespace. There's no need (anymore)
to trim the argument.
Change-Id: Ib060d109f46f79a364a5c8aa33c4f625fe849264
Reviewed-on: https://go-review.googlesource.com/c/go/+/203997
Reviewed-by: Robert Griesemer <gri@golang.org>
In my experimentation, I had found that most non-SSAable expressions were
converted to autotmp variables during AST evaluation. However, this was not true
generally, as witnessed by issue #35213, which has a non-SSAable field reference
of a struct that is not converted to an autotmp. So, I fixed openDeferSave() to
handle non-SSAable nodes more generally, and make sure that these non-SSAable
expressions are not evaluated more than once (which could incorrectly repeat side
effects).
Fixes#35213
Change-Id: I8043d5576b455e94163599e930ca0275e550d594
Reviewed-on: https://go-review.googlesource.com/c/go/+/203888
Run-TryBot: Dan Scales <danscales@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
n.Opt() is used in walkCheckPtrArithmetic to prevent infinite loops. The
fact that it's used today because n.Opt() is not used for OCONVNOP
during walk.go. If that changes, then it's not safe to repalce it
anymore. So doing hard fail if that case happens, the author of new
changes will be noticed and must change the usage of n.Opt() inside
walkCheckPtrArithmetic, too.
Change-Id: Ic7094baa1759c647fc10e82457c19026099a0d47
Reviewed-on: https://go-review.googlesource.com/c/go/+/202497
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
For #10958, #24543, but makes sense on its own.
Change-Id: I2a87dab66b82a1863e4b6512b1f8def51463ce2a
Reviewed-on: https://go-review.googlesource.com/c/go/+/203284
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
"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>
ZeroAuto was used with the ambiguously live logic. The
ambiguously live logic is removed as we switched to stack
objects. It is now never called. Remove.
Change-Id: If4cdd7fed5297f8ab591cc392a76c80f57820856
Reviewed-on: https://go-review.googlesource.com/c/go/+/203538
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@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 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>
It can still be manually disabled again using -d=checkptr=0.
It's also still disabled by default for GOOS=windows, because the
Windows standard library code has a lot of unsafe pointer conversions
that need updating.
Updates #34964.
Change-Id: Ie0b8b4fdf9761565e0dcb00d69997ad896ac233d
Reviewed-on: https://go-review.googlesource.com/c/go/+/201783
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
CL 137156 introduces an intrinsic on AMD64 that executes vfmadd231sd
when feature detection is successful. However, because floating-point
isn't allowed in note handler, the builder disables SSE instructions,
and fails when attempting to execute this instruction. This change
disables FMA on plan9 to immediately use the software fallback.
Fixes#35063.
Change-Id: I87d8f0995bd2f15013d203e618938f5079c9eed2
Reviewed-on: https://go-review.googlesource.com/c/go/+/202617
Reviewed-by: Keith Randall <khr@golang.org>
The root cause of #33658 is that fmt.Printf does have side effects when
printing Type.
typefmt for TINTER will call Type.Fields to get all embedded fields and
methods. The thing is that type.Fields itself will call dowidth, which will
expand the embedded interface, make it non-embedded anymore.
To fix it, we add a marker while we are tracing, so dowidth can know and
return immediately without doing anything.
Fixes#33658
Change-Id: Id4b70ff68a3b802675deae96793fdb8f7ef1a4a7
Reviewed-on: https://go-review.googlesource.com/c/go/+/190537
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Make go test -a -short -gcflags=all=-d=checkptr passes on darwin.
Update #34972
Change-Id: I71cf14ec1faccd4837713aa30c90ed665899b908
Reviewed-on: https://go-review.googlesource.com/c/go/+/202158
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
