Most write barrier calls are inserted by SSA, but copy and append are
lowered to runtime.typedslicecopy during walk. Fix these to set
Func.WBPos and emit the "write barrier" warning, as done for the write
barriers inserted by SSA. As part of this, we refactor setting WBPos
and emitting this warning into the frontend so it can be shared by
both walk and SSA.
Change-Id: I5fe9997d9bdb55e03e01dd58aee28908c35f606b
Reviewed-on: https://go-review.googlesource.com/73411
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
When we remove a nil check, add it back to the free Value pool immediately.
Fixes#18732
Change-Id: I8d644faabbfb52157d3f2d071150ff0342ac28dc
Reviewed-on: https://go-review.googlesource.com/58810
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
When package ssa was created, Type was in package gc.
To avoid circular dependencies, we used an interface (ssa.Type)
to represent type information in SSA.
In the Go 1.9 cycle, gri extricated the Type type from package gc.
As a result, we can now use it in package ssa.
Now, instead of package types depending on package ssa,
it is the other way.
This is a more sensible dependency tree,
and helps compiler performance a bit.
Though this is a big CL, most of the changes are
mechanical and uninteresting.
Interesting bits:
* Add new singleton globals to package types for the special
SSA types Memory, Void, Invalid, Flags, and Int128.
* Add two new Types, TSSA for the special types,
and TTUPLE, for SSA tuple types.
ssa.MakeTuple is now types.NewTuple.
* Move type comparison result constants CMPlt, CMPeq, and CMPgt
to package types.
* We had picked the name "types" in our rules for the handy
list of types provided by ssa.Config. That conflicted with
the types package name, so change it to "typ".
* Update the type comparison routine to handle tuples and special
types inline.
* Teach gc/fmt.go how to print special types.
* We can now eliminate ElemTypes in favor of just Elem,
and probably also some other duplicated Type methods
designed to return ssa.Type instead of *types.Type.
* The ssa tests were using their own dummy types,
and they were not particularly careful about types in general.
Of necessity, this CL switches them to use *types.Type;
it does not make them more type-accurate.
Unfortunately, using types.Type means initializing a bit
of the types universe.
This is prime for refactoring and improvement.
This shrinks ssa.Value; it now fits in a smaller size class
on 64 bit systems. This doesn't have a giant impact,
though, since most Values are preallocated in a chunk.
name old alloc/op new alloc/op delta
Template 37.9MB ± 0% 37.7MB ± 0% -0.57% (p=0.000 n=10+8)
Unicode 28.9MB ± 0% 28.7MB ± 0% -0.52% (p=0.000 n=10+10)
GoTypes 110MB ± 0% 109MB ± 0% -0.88% (p=0.000 n=10+10)
Flate 24.7MB ± 0% 24.6MB ± 0% -0.66% (p=0.000 n=10+10)
GoParser 31.1MB ± 0% 30.9MB ± 0% -0.61% (p=0.000 n=10+9)
Reflect 73.9MB ± 0% 73.4MB ± 0% -0.62% (p=0.000 n=10+8)
Tar 25.8MB ± 0% 25.6MB ± 0% -0.77% (p=0.000 n=9+10)
XML 41.2MB ± 0% 40.9MB ± 0% -0.80% (p=0.000 n=10+10)
[Geo mean] 40.5MB 40.3MB -0.68%
name old allocs/op new allocs/op delta
Template 385k ± 0% 386k ± 0% ~ (p=0.356 n=10+9)
Unicode 343k ± 1% 344k ± 0% ~ (p=0.481 n=10+10)
GoTypes 1.16M ± 0% 1.16M ± 0% -0.16% (p=0.004 n=10+10)
Flate 238k ± 1% 238k ± 1% ~ (p=0.853 n=10+10)
GoParser 320k ± 0% 320k ± 0% ~ (p=0.720 n=10+9)
Reflect 957k ± 0% 957k ± 0% ~ (p=0.460 n=10+8)
Tar 252k ± 0% 252k ± 0% ~ (p=0.133 n=9+10)
XML 400k ± 0% 400k ± 0% ~ (p=0.796 n=10+10)
[Geo mean] 428k 428k -0.01%
Removing all the interface calls helps non-trivially with CPU, though.
name old time/op new time/op delta
Template 178ms ± 4% 173ms ± 3% -2.90% (p=0.000 n=94+96)
Unicode 85.0ms ± 4% 83.9ms ± 4% -1.23% (p=0.000 n=96+96)
GoTypes 543ms ± 3% 528ms ± 3% -2.73% (p=0.000 n=98+96)
Flate 116ms ± 3% 113ms ± 4% -2.34% (p=0.000 n=96+99)
GoParser 144ms ± 3% 140ms ± 4% -2.80% (p=0.000 n=99+97)
Reflect 344ms ± 3% 334ms ± 4% -3.02% (p=0.000 n=100+99)
Tar 106ms ± 5% 103ms ± 4% -3.30% (p=0.000 n=98+94)
XML 198ms ± 5% 192ms ± 4% -2.88% (p=0.000 n=92+95)
[Geo mean] 178ms 173ms -2.65%
name old user-time/op new user-time/op delta
Template 229ms ± 5% 224ms ± 5% -2.36% (p=0.000 n=95+99)
Unicode 107ms ± 6% 106ms ± 5% -1.13% (p=0.001 n=93+95)
GoTypes 696ms ± 4% 679ms ± 4% -2.45% (p=0.000 n=97+99)
Flate 137ms ± 4% 134ms ± 5% -2.66% (p=0.000 n=99+96)
GoParser 176ms ± 5% 172ms ± 8% -2.27% (p=0.000 n=98+100)
Reflect 430ms ± 6% 411ms ± 5% -4.46% (p=0.000 n=100+92)
Tar 128ms ±13% 123ms ±13% -4.21% (p=0.000 n=100+100)
XML 239ms ± 6% 233ms ± 6% -2.50% (p=0.000 n=95+97)
[Geo mean] 220ms 213ms -2.76%
Change-Id: I15c7d6268347f8358e75066dfdbd77db24e8d0c1
Reviewed-on: https://go-review.googlesource.com/42145
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This reduces the size of the ssa export data
by 10%, from 76154 to 67886.
It doesn't appear that #20084, which would do this automatically,
is going to be fixed soon. Do it manually for now.
This speeds up compiling cmd/compile/internal/amd64
and presumably its comrades as well:
name old time/op new time/op delta
CompileAMD64 89.6ms ± 6% 86.7ms ± 5% -3.29% (p=0.000 n=49+47)
name old user-time/op new user-time/op delta
CompileAMD64 116ms ± 5% 112ms ± 5% -3.51% (p=0.000 n=45+42)
name old alloc/op new alloc/op delta
CompileAMD64 26.7MB ± 0% 25.8MB ± 0% -3.26% (p=0.008 n=5+5)
name old allocs/op new allocs/op delta
CompileAMD64 223k ± 0% 213k ± 0% -4.46% (p=0.008 n=5+5)
Updates #20084
Change-Id: I49e8951c5bfce63ad2b7f4fc3bfa0868c53114f9
Reviewed-on: https://go-review.googlesource.com/41493
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Prior to this CL, the SSA backend reported violations
of the //go:nowritebarrier annotation immediately.
This necessitated emitting errors during SSA compilation,
which is not compatible with a concurrent backend.
Instead, check for such violations later.
We already save the data required to do a late check
for violations of the //go:nowritebarrierrec annotation.
Use the same data, and check //go:nowritebarrier at the same time.
One downside to doing this is that now only a single
violation will be reported per function.
Given that this is for the runtime only,
and violations are rare, this seems an acceptable cost.
While we are here, remove several 'nerrors != 0' checks
that are rendered pointless.
Updates #15756Fixes#19250 (as much as it ever can be)
Change-Id: Ia44c4ad5b6fd6f804d9f88d9571cec8d23665cb3
Reviewed-on: https://go-review.googlesource.com/38973
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Suggested by mdempsky in CL 38232.
This allows us to use the Frontend field
to associate frontend state and information
with a function.
See the following CL in the series for examples.
This is a giant CL, but it is almost entirely routine refactoring.
The ssa test API is starting to feel a bit unwieldy.
I will clean it up separately, once the dust has settled.
Passes toolstash -cmp.
Updates #15756
Change-Id: I71c573bd96ff7251935fce1391b06b1f133c3caf
Reviewed-on: https://go-review.googlesource.com/38327
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
This makes ssa.Func, ssa.Cache, and ssa.Config fulfill
the roles laid out for them in CL 38160.
The only non-trivial change in this CL is how cached
values and blocks get IDs. Prior to this CL, their IDs were
assigned as part of resetting the cache, and only modified
IDs were reset. This required knowing how many values and
blocks were modified, which required a tight coupling between
ssa.Func and ssa.Config. To eliminate that coupling,
we now zero values and blocks during reset,
and assign their IDs when they are used.
Since unused values and blocks have ID == 0,
we can efficiently find the last used value/block,
to avoid zeroing everything.
Bulk zeroing is efficient, but not efficient enough
to obviate the need to avoid zeroing everything every time.
As a happy side-effect, ssa.Func.Free is no longer necessary.
DebugHashMatch and friends now belong in func.go.
They have been left in place for clarity and review.
I will move them in a subsequent CL.
Passes toolstash -cmp. No compiler performance impact.
No change in 'go test cmd/compile/internal/ssa' execution time.
Change-Id: I2eb7af58da067ef6a36e815a6f386cfe8634d098
Reviewed-on: https://go-review.googlesource.com/38167
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Remove size AuxInt in Store, and alignment in Move/Zero. We still
pass size AuxInt to Move/Zero, as it is used for partial Move/Zero
lowering (e.g. cmd/compile/internal/ssa/gen/386.rules:288).
SizeAndAlign is gone.
Passes "toolstash -cmp" on std.
Change-Id: I1ca34652b65dd30de886940e789fcf41d521475d
Reviewed-on: https://go-review.googlesource.com/38150
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Now that the write barrier insertion is moved to SSA, the SSA
building code can be simplified.
Updates #17583.
Change-Id: I5cacc034b11aa90b0abe6f8dd97e4e3994e2bc25
Reviewed-on: https://go-review.googlesource.com/36840
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The line between ssa.Func and ssa.Config has blurred.
Concurrent compilation in the backend will require more precision.
This CL lays out an (aspirational) organization.
The implementation will come in follow-up CLs,
once the organization is settled.
ssa.Config holds basic compiler configuration,
mostly arch-specific information.
It is configured once, early on, and is readonly,
so it is safe for concurrent use.
ssa.Func is a single-shot object used for
compiling a single Func. It is not concurrency-safe
and not re-usable.
ssa.Cache is a multi-use object used to avoid
expensive allocations during compilation.
Each ssa.Func is given an ssa.Cache to use.
ssa.Cache is not concurrency-safe.
Change-Id: Id02809b6f3541541cac6c27bbb598834888ce1cc
Reviewed-on: https://go-review.googlesource.com/38160
Reviewed-by: Keith Randall <khr@golang.org>
Previously we always issued a spill right after the op
that was being spilled. This CL pushes spills father away
from the generator, hopefully pushing them into unlikely branches.
For example:
x = ...
if unlikely {
call ...
}
... use x ...
Used to compile to
x = ...
spill x
if unlikely {
call ...
restore x
}
It now compiles to
x = ...
if unlikely {
spill x
call ...
restore x
}
This is particularly useful for code which appends, as the only
call is an unlikely call to growslice. It also helps for the
spills needed around write barrier calls.
The basic algorithm is walk down the dominator tree following a
path where the block still dominates all of the restores. We're
looking for a block that:
1) dominates all restores
2) has the value being spilled in a register
3) has a loop depth no deeper than the value being spilled
The walking-down code is iterative. I was forced to limit it to
searching 100 blocks so it doesn't become O(n^2). Maybe one day
we'll find a better way.
I had to delete most of David's code which pushed spills out of loops.
I suspect this CL subsumes most of the cases that his code handled.
Generally positive performance improvements, but hard to tell for sure
with all the noise. (compilebench times are unchanged.)
name old time/op new time/op delta
BinaryTree17-12 2.91s ±15% 2.80s ±12% ~ (p=0.063 n=10+10)
Fannkuch11-12 3.47s ± 0% 3.30s ± 4% -4.91% (p=0.000 n=9+10)
FmtFprintfEmpty-12 48.0ns ± 1% 47.4ns ± 1% -1.32% (p=0.002 n=9+9)
FmtFprintfString-12 85.6ns ±11% 79.4ns ± 3% -7.27% (p=0.005 n=10+10)
FmtFprintfInt-12 91.8ns ±10% 85.9ns ± 4% ~ (p=0.203 n=10+9)
FmtFprintfIntInt-12 135ns ±13% 127ns ± 1% -5.72% (p=0.025 n=10+9)
FmtFprintfPrefixedInt-12 167ns ± 1% 168ns ± 2% ~ (p=0.580 n=9+10)
FmtFprintfFloat-12 249ns ±11% 230ns ± 1% -7.32% (p=0.000 n=10+10)
FmtManyArgs-12 504ns ± 7% 506ns ± 1% ~ (p=0.198 n=9+9)
GobDecode-12 6.95ms ± 1% 7.04ms ± 1% +1.37% (p=0.001 n=10+10)
GobEncode-12 6.32ms ±13% 6.04ms ± 1% ~ (p=0.063 n=10+10)
Gzip-12 233ms ± 1% 235ms ± 0% +1.01% (p=0.000 n=10+9)
Gunzip-12 40.1ms ± 1% 39.6ms ± 0% -1.12% (p=0.000 n=10+8)
HTTPClientServer-12 227µs ± 9% 221µs ± 5% ~ (p=0.114 n=9+8)
JSONEncode-12 16.1ms ± 2% 15.8ms ± 1% -2.09% (p=0.002 n=9+8)
JSONDecode-12 61.8ms ±11% 57.9ms ± 1% -6.30% (p=0.000 n=10+9)
Mandelbrot200-12 4.30ms ± 3% 4.28ms ± 1% ~ (p=0.203 n=10+8)
GoParse-12 3.18ms ± 2% 3.18ms ± 2% ~ (p=0.579 n=10+10)
RegexpMatchEasy0_32-12 76.7ns ± 1% 77.5ns ± 1% +0.92% (p=0.002 n=9+8)
RegexpMatchEasy0_1K-12 239ns ± 3% 239ns ± 1% ~ (p=0.204 n=10+10)
RegexpMatchEasy1_32-12 71.4ns ± 1% 70.6ns ± 0% -1.15% (p=0.000 n=10+9)
RegexpMatchEasy1_1K-12 383ns ± 2% 390ns ±10% ~ (p=0.181 n=8+9)
RegexpMatchMedium_32-12 114ns ± 0% 113ns ± 1% -0.88% (p=0.000 n=9+8)
RegexpMatchMedium_1K-12 36.3µs ± 1% 36.8µs ± 1% +1.59% (p=0.000 n=10+8)
RegexpMatchHard_32-12 1.90µs ± 1% 1.90µs ± 1% ~ (p=0.341 n=10+10)
RegexpMatchHard_1K-12 59.4µs ±11% 57.8µs ± 1% ~ (p=0.968 n=10+9)
Revcomp-12 461ms ± 1% 462ms ± 1% ~ (p=1.000 n=9+9)
Template-12 67.5ms ± 1% 66.3ms ± 1% -1.77% (p=0.000 n=10+8)
TimeParse-12 314ns ± 3% 309ns ± 0% -1.56% (p=0.000 n=9+8)
TimeFormat-12 340ns ± 2% 331ns ± 1% -2.79% (p=0.000 n=10+10)
The go binary is 0.2% larger. Not really sure why the size
would change.
Change-Id: Ia5116e53a3aeb025ef350ffc51c14ae5cc17871c
Reviewed-on: https://go-review.googlesource.com/34822
Reviewed-by: David Chase <drchase@google.com>
Minor fix, because it's the right thing to do.
No significant impact.
Change-Id: I2138285d397494daa9a88c414149c2a7860edd7e
Reviewed-on: https://go-review.googlesource.com/38001
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Values have an Aux and an AuxInt.
We're setting AuxInt, not Aux.
Say so.
Change-Id: I41aa783273bb7e1ba47c941aa4233f818e37dadd
Reviewed-on: https://go-review.googlesource.com/37997
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Rather than collecting static data nodes to be written out later, just
write them out immediately.
Change-Id: I51708b690e94bc3e288b4d6ba3307bf738a80f64
Reviewed-on: https://go-review.googlesource.com/36352
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
XPos is a compact (8 instead of 16 bytes on a 64bit machine) source
position representation. There is a 1:1 correspondence between each
XPos and each regular Pos, translated via a global table.
In some sense this brings back the LineHist, though positions can
track line and column information; there is a O(1) translation
between the representations (no binary search), and the translation
is factored out.
The size increase with the prior change is brought down again and
the compiler speed is in line with the master repo (measured on
the same "quiet" machine as for prior change):
name old time/op new time/op delta
Template 256ms ± 1% 262ms ± 2% ~ (p=0.063 n=5+4)
Unicode 132ms ± 1% 135ms ± 2% ~ (p=0.063 n=5+4)
GoTypes 891ms ± 1% 871ms ± 1% -2.28% (p=0.016 n=5+4)
Compiler 3.84s ± 2% 3.89s ± 2% ~ (p=0.413 n=5+4)
MakeBash 47.1s ± 1% 46.2s ± 2% ~ (p=0.095 n=5+5)
name old user-ns/op new user-ns/op delta
Template 309M ± 1% 314M ± 2% ~ (p=0.111 n=5+4)
Unicode 165M ± 1% 172M ± 9% ~ (p=0.151 n=5+5)
GoTypes 1.14G ± 2% 1.12G ± 1% ~ (p=0.063 n=5+4)
Compiler 5.00G ± 1% 4.96G ± 1% ~ (p=0.286 n=5+4)
Change-Id: Icc570cc60ab014d8d9af6976f1f961ab8828cc47
Reviewed-on: https://go-review.googlesource.com/34506
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Loop breaking with a counter. Benchmarked (see comments),
eyeball checked for sanity on popular loops. This code
ought to handle loops in general, and properly inserts phi
functions in cases where the earlier version might not have.
Includes test, plus modifications to test/run.go to deal with
timeout and killing looping test. Tests broken by the addition
of extra code (branch frequency and live vars) for added
checks turn the check insertion off.
If GOEXPERIMENT=preemptibleloops, the compiler inserts reschedule
checks on every backedge of every reducible loop. Alternately,
specifying GO_GCFLAGS=-d=ssa/insert_resched_checks/on will
enable it for a single compilation, but because the core Go
libraries contain some loops that may run long, this is less
likely to have the desired effect.
This is intended as a tool to help in the study and diagnosis
of GC and other latency problems, now that goal STW GC latency
is on the order of 100 microseconds or less.
Updates #17831.
Updates #10958.
Change-Id: I6206c163a5b0248e3f21eb4fc65f73a179e1f639
Reviewed-on: https://go-review.googlesource.com/33910
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This is a mostly mechanical rename followed by manual fixes where necessary.
Change-Id: Ie5c670b133db978f15dc03e50dc2da0c80fc8842
Reviewed-on: https://go-review.googlesource.com/34137
Reviewed-by: David Lazar <lazard@golang.org>
This is a step toward chosing a different position representation.
By introducing an explicit type, it will be easier to make the
transition step-wise while ensuring everything keeps running.
This has been reviewed via https://go-review.googlesource.com/#/c/34025/.
Change-Id: Ibceddcd62d8f346321ac3250e3940e9c436ed684
Reviewed-on: https://go-review.googlesource.com/34132
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Lazar <lazard@golang.org>
For very large input files, use of GOSSAFUNC to obtain a dump
after compilation steps can lead to both unwieldy large output
files and unwieldy larger processes (because the output is
buffered in a string). This flag
-d=ssa/<phase>/dump:<function name>
provides finer control of what is dumped, into a smaller
file, and with less memory overhead in the running compiler.
The special phase name "build" is added to allow printing
of the just-built ssa before any transformations are applied.
This was helpful in making sense of the gogo/protobuf
problems.
The output format was tweaked to remove gratuitous spaces,
and a crude -d=ssa/help help text was added.
Change-Id: If7516e22203420eb6ed3614f7cee44cb9260f43e
Reviewed-on: https://go-review.googlesource.com/23044
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Should be more asymptotically happy.
We process each variable in turn to find all the
locations where it needs a phi (the dominance frontier
of all of its definitions). Then we add all those phis.
This takes O(n * #variables), although hopefully much less.
Then we do a single tree walk to match all the
FwdRefs with the nearest definition or phi.
This takes O(n) time.
The one remaining inefficiency is that we might end up
introducing a bunch of dead phis in the first step.
A TODO is to introduce phis only where they might be
used by a read.
The old algorithm is still faster on small functions,
so there's a cutover size (currently 500 blocks).
This algorithm supercedes the David's sparse phi
placement algorithm for large functions.
Lowers compile time of example from #14934 from
~10 sec to ~4 sec.
Lowers compile time of example from #16361 from
~4.5 sec to ~3 sec.
Lowers #16407 from ~20 min to ~30 sec.
Update #14934
Update #16361Fixes#16407
Change-Id: I1cff6364e1623c143190b6a924d7599e309db58f
Reviewed-on: https://go-review.googlesource.com/30163
Reviewed-by: David Chase <drchase@google.com>
We compute a lot of stuff based off the CFG: postorder traversal,
dominators, dominator tree, loop nest. Multiple phases use this
information and we end up recomputing some of it. Add a cache
for this information so if the CFG hasn't changed, we can reuse
the previous computation.
Change-Id: I9b5b58af06830bd120afbee9cfab395a0a2f74b2
Reviewed-on: https://go-review.googlesource.com/29356
Reviewed-by: David Chase <drchase@google.com>
Rip out the code that allows SSA to be used conditionally.
No longer exists:
ssa=0 flag
GOSSAHASH
GOSSAPKG
SSATEST
GOSSAFUNC now only controls the printing of the IR/html.
Still need to rip out all of the old backend. It should no longer be
callable after this CL.
Update #16357
Change-Id: Ib30cc18fba6ca52232c41689ba610b0a94aa74f5
Reviewed-on: https://go-review.googlesource.com/29155
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
Atomic swap, add/and/or, compare and swap.
Also works on amd64p32.
Change-Id: Idf2d8f3e1255f71deba759e6e75e293afe4ab2ba
Reviewed-on: https://go-review.googlesource.com/27813
Reviewed-by: Cherry Zhang <cherryyz@google.com>
This adds a sparse method for locating nearest ancestors
in a dominator tree, and checks blocks with more than one
predecessor for differences and inserts phi functions where
there are.
Uses reversed post order to cut number of passes, running
it from first def to last use ("last use" for paramout and
mem is end-of-program; last use for a phi input from a
backedge is the source of the back edge)
Includes a cutover from old algorithm to new to avoid paying
large constant factor for small programs. This keeps normal
builds running at about the same time, while not running
over-long on large machine-generated inputs.
Add "phase" flags for ssa/build -- ssa/build/stats prints
number of blocks, values (before and after linking references
and inserting phis, so expansion can be measured), and their
product; the product governs the cutover, where a good value
seems to be somewhere between 1 and 5 million.
Among the files compiled by make.bash, this is the shape of
the tail of the distribution for #blocks, #vars, and their
product:
#blocks #vars product
max 6171 28180 173,898,780
99.9% 1641 6548 10,401,878
99% 463 1909 873,721
95% 152 639 95,235
90% 84 359 30,021
The old algorithm is indeed usually fastest, for 99%ile
values of usually.
The fix to LookupVarOutgoing
( https://go-review.googlesource.com/#/c/22790/ )
deals with some of the same problems addressed by this CL,
but on at least one bug ( #15537 ) this change is still
a significant help.
With this CL:
/tmp/gopath$ rm -rf pkg bin
/tmp/gopath$ time go get -v -gcflags -memprofile=y.mprof \
github.com/gogo/protobuf/test/theproto3/combos/...
...
real 4m35.200s
user 13m16.644s
sys 0m36.712s
and pprof reports 3.4GB allocated in one of the larger profiles
With tip:
/tmp/gopath$ rm -rf pkg bin
/tmp/gopath$ time go get -v -gcflags -memprofile=y.mprof \
github.com/gogo/protobuf/test/theproto3/combos/...
...
real 10m36.569s
user 25m52.286s
sys 4m3.696s
and pprof reports 8.3GB allocated in the same larger profile
With this CL, most of the compilation time on the benchmarked
input is spent in register/stack allocation (cumulative 53%)
and in the sparse lookup algorithm itself (cumulative 20%).
Fixes#15537.
Change-Id: Ia0299dda6a291534d8b08e5f9883216ded677a00
Reviewed-on: https://go-review.googlesource.com/22342
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
They have different semantics.
Equal is stricter and is designed for the front-end.
Compare is looser and cheaper and is designed for the back-end.
To avoid possible regression, remove Equal from ssa.Type.
Updates #15043
Change-Id: Ie23ce75ff6b4d01b7982e0a89e6f81b5d099d8d6
Reviewed-on: https://go-review.googlesource.com/21483
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Keep track of how many uses each Value has. Each appearance in
Value.Args and in Block.Control counts once.
The number of uses of a value is generically useful to
constrain rewrite rules. For instance, we might want to
prevent merging index operations into loads if the same
index expression is used lots of times.
But I have one use in particular for which the use count is required.
We must make sure we don't combine ops with loads if the load has
more than one use. Otherwise, we may split a single load
into multiple loads and that breaks perceived behavior in
the presence of races. In particular, the load of m.state
in sync/mutex.go:Lock can't be done twice. (I have a separate
CL which triggers the mutex failure. This CL has a test which
demonstrates a similar failure.)
Change-Id: Icaafa479239f48632a069d0c3f624e6ebc6b1f0e
Reviewed-on: https://go-review.googlesource.com/20790
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Todd Neal <todd@tneal.org>
Line numbers are always int32, so the Warnl function should take the
line number as an int32 as well. This matches gc.Warnl and removes
a cast every place it's used.
Change-Id: I5d6201e640d52ec390eb7174f8fd8c438d4efe58
Reviewed-on: https://go-review.googlesource.com/20662
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Split the auxFloat type into 32/64 bit versions and perform checking for
exactly representable float32 values. Perform const folding on
float32/64. Comment out some const negation rules that the frontend
already performs.
Change-Id: Ib3f8d59fa8b30e50fe0267786cfb3c50a06169d2
Reviewed-on: https://go-review.googlesource.com/20568
Run-TryBot: Todd Neal <todd@tneal.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
When calling freeValue for possible const values, remove them from the
cache as well.
Change-Id: I087ed592243e33c58e5db41700ab266fc70196d9
Reviewed-on: https://go-review.googlesource.com/20481
Run-TryBot: Todd Neal <tolchz@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.
This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:
$ perl -i -npe 's,^(\s*// .+[a-z]\.) +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.) +([A-Z])')
$ go test go/doc -update
Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
The -d compiler flag can also specify ssa phase and flag,
for example -d=ssa/generic_cse/time,ssa/generic_cse/stats
Spaces in the phase names can be specified with an
underscore. Flags currently parsed (not necessarily
recognized by the phases yet) are:
on, off, mem, time, debug, stats, and test
On, off and time are handled in the harness,
debug, stats, and test are interpreted by the phase itself.
The pass is now attached to the Func being compiled, and a
new method logStats(key, ...value) on *Func to encourage a
semi-standardized format for that output. Output fields
are separated by tabs to ease digestion by awk and
spreadsheets. For example,
if f.pass.stats > 0 {
f.logStat("CSE REWRITES", rewrites)
}
Change-Id: I16db2b5af64c50ca9a47efeb51d961147a903abc
Reviewed-on: https://go-review.googlesource.com/19885
Reviewed-by: Keith Randall <khr@golang.org>
Reviewed-by: Todd Neal <todd@tneal.org>
Move the cached sparse sets to the Config. I tested make.bash with
pre-allocating sets of size 150 and not caching very small sets, but the
difference between this implementation (no min size, no preallocation)
and a min size with preallocation was fairly negligible:
Number of sparse sets allocated:
Cached in Config w/none preallocated no min size 3684 *this CL*
Cached in Config w/three preallocated no min size 3370
Cached in Config w/three preallocated min size=150 3370
Cached in Config w/none preallocated min size=150 15947
Cached in Func, w/no min 96996 *previous code*
Change-Id: I7f9de8a7cae192648a7413bfb18a6690fad34375
Reviewed-on: https://go-review.googlesource.com/19152
Reviewed-by: Keith Randall <khr@golang.org>
From memory profiling, about 3% reduction in allocation count.
Change-Id: I4b662d55b8a94fe724759a2b22f05a08d0bf40f8
Reviewed-on: https://go-review.googlesource.com/19103
Reviewed-by: Keith Randall <khr@golang.org>
