"abc"[1] is not like 'b', in that -"abc"[1] is uint8 math, not ideal constant math.
Delay the constantification until after ideal constant folding is over.
Fixes#11370.
Change-Id: Iba2fc00ca2455959e7bab8f4b8b4aac14b1f9858
Reviewed-on: https://go-review.googlesource.com/15740
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Previously, we used OKEY nodes to represent keyed struct literal
elements. The field names were represented by an ONAME node, but this
is clumsy because it's the only remaining case where ONAME was used to
represent a bare identifier and not a variable.
This CL introduces a new OSTRUCTKEY node op for use in struct
literals. These ops instead store the field name in the node's own Sym
field. This is similar in spirit to golang.org/cl/20890.
Significant reduction in allocations for struct literal heavy code
like package unicode:
name old time/op new time/op delta
Template 345ms ± 6% 341ms ± 6% ~ (p=0.141 n=29+28)
Unicode 200ms ± 9% 184ms ± 7% -7.77% (p=0.000 n=29+30)
GoTypes 1.04s ± 3% 1.05s ± 3% ~ (p=0.096 n=30+30)
Compiler 4.47s ± 9% 4.49s ± 6% ~ (p=0.890 n=29+29)
name old user-ns/op new user-ns/op delta
Template 523M ±13% 516M ±17% ~ (p=0.400 n=29+30)
Unicode 334M ±27% 314M ±30% ~ (p=0.093 n=30+30)
GoTypes 1.53G ±10% 1.52G ±10% ~ (p=0.572 n=30+30)
Compiler 6.28G ± 7% 6.34G ±11% ~ (p=0.300 n=30+30)
name old alloc/op new alloc/op delta
Template 44.5MB ± 0% 44.4MB ± 0% -0.35% (p=0.000 n=27+30)
Unicode 39.2MB ± 0% 34.5MB ± 0% -11.79% (p=0.000 n=26+30)
GoTypes 125MB ± 0% 125MB ± 0% -0.12% (p=0.000 n=29+30)
Compiler 515MB ± 0% 515MB ± 0% -0.10% (p=0.000 n=29+30)
name old allocs/op new allocs/op delta
Template 426k ± 0% 424k ± 0% -0.39% (p=0.000 n=29+30)
Unicode 374k ± 0% 323k ± 0% -13.67% (p=0.000 n=29+30)
GoTypes 1.21M ± 0% 1.21M ± 0% -0.14% (p=0.000 n=29+29)
Compiler 4.40M ± 0% 4.39M ± 0% -0.13% (p=0.000 n=29+30)
Passes toolstash/buildall.
Change-Id: Iba4ee765dd1748f67e52fcade1cd75c9f6e13fa9
Reviewed-on: https://go-review.googlesource.com/30974
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
aindex is overkill when it's only ever used with known integer
constants, so just use typArray directly instead.
Change-Id: I43fc14e604172df859b3ad9d848d219bbe48e434
Reviewed-on: https://go-review.googlesource.com/30979
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
To compile:
m[k] = v
instead of:
mapassign(maptype, m, &k, &v), do
do:
*mapassign(maptype, m, &k) = v
mapassign returns a pointer to the value slot in the map. It is just
like mapaccess except that it will allocate a new slot if k is not
already present in the map.
This makes map accesses faster but potentially larger (codewise).
It is faster because the write into the map is done when the compiler
knows the concrete type, so it can be done with a few store
instructions instead of calling typedmemmove. We also potentially
avoid stack temporaries to hold v.
The code can be larger when the map has pointers in its value type,
since there is a write barrier call in addition to the mapassign call.
That makes the code at the callsite a bit bigger (go binary is 0.3%
bigger).
This CL is in preparation for doing operations like m[k] += v with
only a single runtime call. That will roughly double the speed of
such operations.
Update #17133
Update #5147
Change-Id: Ia435f032090a2ed905dac9234e693972fe8c2dc5
Reviewed-on: https://go-review.googlesource.com/30815
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
When processing a fallthrough, the casebody function in swt.go
checks that the last statement has indeed Op == OXFALL (not-processed
fallthrough) before setting it to OFALL (processed fallthrough).
Unfortunately, sometimes the fallthrough statement won't be in the
last node. For example, in
case 0:
return func() int {return 1}()
fallthrough
the compiler generates
autotmp_0 = (func literal)(); return autotmp_0; fallthrough; <node VARKILL>
with an OVARKILL node in the last position. casebody will find that
last.Op != OXFALL, won't mark the fallthrough as processed, and the
fallthrough line will cause a "fallthrough statement out of place" error.
To fix this, we change casebody so that it searches for the fallthrough
statement backwards in the statements list, without assuming that it'll
be in the last position.
Fixes#13262
Change-Id: I366c6caa7fd7442d365bd7a08cc66a552212d9b2
Reviewed-on: https://go-review.googlesource.com/22921
Run-TryBot: Quentin Smith <quentin@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Quentin Smith <quentin@golang.org>
Instrumenting copy and append for the race detector changes them to call
different functions. In the runtime package the alternate functions are
not marked as nosplit. This caused a crash in the SIGPROF handler when
invoked on a non-Go thread in a program built with the race detector. In
some cases the handler can call copy, the race detector changed that to
a call to a non-nosplit function, the function tried to check the stack
guard, and crashed because it was running on a non-Go thread. The
SIGPROF handler is written carefully to avoid such problems, but hidden
function calls are difficult to avoid.
Fix this by changing the compiler to not instrument copy and append when
compiling the runtime package. Change the runtime package to add
explicit race checks for the only code I could find where copy is used
to write to user data (append is never used).
Change-Id: I11078a66c0aaa459a7d2b827b49f4147922050af
Reviewed-on: https://go-review.googlesource.com/29472
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
No point in calling a function when we can build the interface
using a known type (or itab) and the address of a local.
Get rid of third arg (preallocated stack space) to convT2{I,E}.
Makes go binary smaller by 0.2%
benchmark old ns/op new ns/op delta
BenchmarkEfaceInteger-8 16.7 10.1 -39.52%
Update #17118
Update #15375
Change-Id: I9724a1f802bfa1e3957bf1856b55558278e198a2
Reviewed-on: https://go-review.googlesource.com/29373
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Old backends did not implement them, but SSA do.
Change-Id: I543b2281dcf4bab0da37c9b1f26a5ef55a0ea11b
Reviewed-on: https://go-review.googlesource.com/29278
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Follow up to CL 29134. Generated with gofmt -r 'Nod -> nod', plus
three manual adjustments to the comments in syntax/parser.go
Change-Id: I02920f7ab10c70b6e850457b42d5fe35f1f3821a
Reviewed-on: https://go-review.googlesource.com/29136
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
Unroll s == "ab" to
len(s) == 2 && s[0] == 'a' && s[1] == 'b'
This generates faster and shorter code
by avoiding a runtime call.
Do something similar for !=.
The cutoff length is 6. This was chosen empirically
by examining binary sizes on arm, arm64, 386, and amd64
using the SSA backend.
For all architectures examined, 4, 5, and 6 were
the ideal cutoff, with identical binary sizes.
The distribution of constant string equality sizes
during 'go build -a std' is:
40.81% 622 len 0
14.11% 215 len 4
9.45% 144 len 1
7.81% 119 len 3
7.48% 114 len 5
5.12% 78 len 7
4.13% 63 len 2
3.54% 54 len 8
2.69% 41 len 6
1.18% 18 len 10
0.85% 13 len 9
0.66% 10 len 14
0.59% 9 len 17
0.46% 7 len 11
0.26% 4 len 12
0.20% 3 len 19
0.13% 2 len 13
0.13% 2 len 15
0.13% 2 len 16
0.07% 1 len 20
0.07% 1 len 23
0.07% 1 len 33
0.07% 1 len 36
A cutoff of length 6 covers most of the cases.
Benchmarks on amd64 comparing a string to a constant of length 3:
Cmp/1same-8 4.78ns ± 6% 0.94ns ± 9% -80.26% (p=0.000 n=20+20)
Cmp/1diffbytes-8 6.43ns ± 6% 0.96ns ±11% -85.13% (p=0.000 n=20+20)
Cmp/3same-8 4.71ns ± 5% 1.28ns ± 5% -72.90% (p=0.000 n=20+20)
Cmp/3difffirstbyte-8 6.33ns ± 7% 1.27ns ± 7% -79.90% (p=0.000 n=20+20)
Cmp/3difflastbyte-8 6.34ns ± 8% 1.26ns ± 9% -80.13% (p=0.000 n=20+20)
The change to the prove test preserves the
existing intent of the test. When the string was
short, there was a new "proved in bounds" report
that referred to individual byte comparisons.
Change-Id: I593ac303b0d11f275672090c5c786ea0c6b8da13
Reviewed-on: https://go-review.googlesource.com/26758
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
After the removal of the old backend many types are no longer referenced
outside internal/gc. Make these functions private so that tools like
honnef.co/go/unused can spot when they become dead code. In doing so
this CL identified several previously public helpers which are no longer
used, so removes them.
This should be the last of the public functions.
Change-Id: I7e9c4e72f86f391b428b9dddb6f0d516529706c3
Reviewed-on: https://go-review.googlesource.com/29134
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
After the removal of the old backend many types are no longer referenced
outside internal/gc. Make these functions private so that tools like
honnef.co/go/unused can spot when they become dead code. In doing so
this CL identified several previously public helpers which are no longer
used, so removes them.
Change-Id: Idc2d485f493206de9d661bd3cb0ecb4684177b32
Reviewed-on: https://go-review.googlesource.com/29133
Run-TryBot: Dave Cheney <dave@cheney.net>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
when not instrumenting:
- Intrinsify uses of slicebytetostringtmp within the runtime package
in the ssa backend.
- Pass OARRAYBYTESTRTMP nodes to the compiler backends for lowering
instead of generating calls to slicebytetostringtmp.
name old time/op new time/op delta
ConcatStringAndBytes-4 27.9ns ± 2% 24.7ns ± 2% -11.52% (p=0.000 n=43+43)
Fixes#17044
Change-Id: I51ce9c3b93284ce526edd0234f094e98580faf2d
Reviewed-on: https://go-review.googlesource.com/29017
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
- also consistently use %v instead of %s when we have a (gc) Formatter
- rewrite done automatically using Formats test in -u (update) mode
- manual update of format strings that were not single string constants
- updated fmt.go, fmt_test.go accordingly
- fmt_test: permit "%T" always
Change-Id: I8f0704286aba5704600ad0c4a4484005b79b905d
Reviewed-on: https://go-review.googlesource.com/28954
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
The ctxt parameter is always set to 0 on entry into anylit so make this
parameter a literal constant, and where possibly remove ctxt as a parameter
where it is known to be a constant zero.
Passes toolstash -cmp.
This is a re-creation of CL 28221 by Dave Cheney.
That CL was graciously reverted in CL 28480
to make merging other CLs easier.
Change-Id: If7a57bf0e27774d9890adbc30af9fabb4aff1058
Reviewed-on: https://go-review.googlesource.com/28483
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dave Cheney <dave@cheney.net>
They were almost identical.
Merge them and some of their calling code.
Passes toolstash -cmp.
Change-Id: I9e92a864a6c09c9e18ed52dc247a678467e344ba
Reviewed-on: https://go-review.googlesource.com/26754
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Does not pass toolstash -cmp due to changed export data,
but the cmd/go binary (which doesn't contain export data)
is bit-for-bit identical.
Change-Id: I6b12f9de18cf7da528e9207dccbf8f08c969f142
Reviewed-on: https://go-review.googlesource.com/26753
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
The ctxt parameter is always set to 0 on entry into anylit so make this
parameter a literal constant, and where possibly remove ctxt as a parameter
where it is known to be a constant zero.
Change-Id: I3e76e06456d7b1a1ea875ffeb2efefa4a1ff5a7e
Reviewed-on: https://go-review.googlesource.com/28221
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Where possible generate calls to runtime makeslice with int arguments
during compile time instead of makeslice with int64 arguments.
This eliminates converting arguments for calls to makeslice with
int64 arguments for platforms where int64 values do not fit into
arguments of type int.
godoc 386 binary shrinks by approximately 12 kilobyte.
amd64:
name old time/op new time/op delta
MakeSlice-2 29.8ns ± 1% 29.8ns ± 1% ~ (p=1.000 n=24+24)
386:
name old time/op new time/op delta
MakeSlice-2 52.3ns ± 0% 45.9ns ± 0% -12.17% (p=0.000 n=25+22)
Fixes #15357
Change-Id: Icb8701bb63c5a83877d26c8a4b78e782ba76de7c
Reviewed-on: https://go-review.googlesource.com/27851
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
This CL reworks walkcompare for clarity and concision.
It also makes one significant functional change.
(The functional change is hard to separate cleanly
from the cleanup, so I just did them together.)
When inlining and unrolling an equality comparison
for a small struct or array, compare the elements like:
a[0] == b[0] && a[1] == b[1]
rather than
pa := &a
pb := &b
pa[0] == pb[0] && pa[1] == pb[1]
The result is the same, but taking the address
and working through the indirect
forces the backends to generate less efficient code.
This is only an improvement with the SSA backend.
However, every port but s390x now has a working
SSA backend, and switching to the SSA backend
by default everywhere is a priority for Go 1.8.
It thus seems reasonable to start to prioritize
SSA performance over the old backend.
Updates #15303
Sample code:
type T struct {
a, b int8
}
func g(a T) bool {
return a == T{1, 2}
}
SSA before:
"".g t=1 size=80 args=0x10 locals=0x8
0x0000 00000 (badeq.go:7) TEXT "".g(SB), $8-16
0x0000 00000 (badeq.go:7) SUBQ $8, SP
0x0004 00004 (badeq.go:7) FUNCDATA $0, gclocals·23e8278e2b69a3a75fa59b23c49ed6ad(SB)
0x0004 00004 (badeq.go:7) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
0x0004 00004 (badeq.go:8) MOVBLZX "".a+16(FP), AX
0x0009 00009 (badeq.go:8) MOVB AL, "".autotmp_0+6(SP)
0x000d 00013 (badeq.go:8) MOVBLZX "".a+17(FP), AX
0x0012 00018 (badeq.go:8) MOVB AL, "".autotmp_0+7(SP)
0x0016 00022 (badeq.go:8) MOVB $0, "".autotmp_1+4(SP)
0x001b 00027 (badeq.go:8) MOVB $1, "".autotmp_1+4(SP)
0x0020 00032 (badeq.go:8) MOVB $2, "".autotmp_1+5(SP)
0x0025 00037 (badeq.go:8) MOVBLZX "".autotmp_0+6(SP), AX
0x002a 00042 (badeq.go:8) MOVBLZX "".autotmp_1+4(SP), CX
0x002f 00047 (badeq.go:8) CMPB AL, CL
0x0031 00049 (badeq.go:8) JNE 70
0x0033 00051 (badeq.go:8) MOVBLZX "".autotmp_0+7(SP), AX
0x0038 00056 (badeq.go:8) CMPB AL, $2
0x003a 00058 (badeq.go:8) SETEQ AL
0x003d 00061 (badeq.go:8) MOVB AL, "".~r1+24(FP)
0x0041 00065 (badeq.go:8) ADDQ $8, SP
0x0045 00069 (badeq.go:8) RET
0x0046 00070 (badeq.go:8) MOVB $0, AL
0x0048 00072 (badeq.go:8) JMP 61
SSA after:
"".g t=1 size=32 args=0x10 locals=0x0
0x0000 00000 (badeq.go:7) TEXT "".g(SB), $0-16
0x0000 00000 (badeq.go:7) NOP
0x0000 00000 (badeq.go:7) NOP
0x0000 00000 (badeq.go:7) FUNCDATA $0, gclocals·23e8278e2b69a3a75fa59b23c49ed6ad(SB)
0x0000 00000 (badeq.go:7) FUNCDATA $1, gclocals·33cdeccccebe80329f1fdbee7f5874cb(SB)
0x0000 00000 (badeq.go:8) MOVBLZX "".a+8(FP), AX
0x0005 00005 (badeq.go:8) CMPB AL, $1
0x0007 00007 (badeq.go:8) JNE 25
0x0009 00009 (badeq.go:8) MOVBLZX "".a+9(FP), CX
0x000e 00014 (badeq.go:8) CMPB CL, $2
0x0011 00017 (badeq.go:8) SETEQ AL
0x0014 00020 (badeq.go:8) MOVB AL, "".~r1+16(FP)
0x0018 00024 (badeq.go:8) RET
0x0019 00025 (badeq.go:8) MOVB $0, AL
0x001b 00027 (badeq.go:8) JMP 20
Change-Id: I120185d58012b7bbcdb1ec01225b5b08d0855d86
Reviewed-on: https://go-review.googlesource.com/22277
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
When T is a scalar, there are no runtime calls
required, which makes this a clear win.
encoding/binary:
WriteInts-8 958ns ± 3% 864ns ± 2% -9.80% (p=0.000 n=15+15)
This also considerably shrinks a core fmt
routine:
Before: "".(*pp).printArg t=1 size=3952 args=0x20 locals=0xf0
After: "".(*pp).printArg t=1 size=2624 args=0x20 locals=0x98
Unfortunately, I find it very hard to get stable
numbers out of the fmt benchmarks due to thermal scaling.
Change-Id: I1278006b030253bf8e48dc7631d18985cdaa143d
Reviewed-on: https://go-review.googlesource.com/26659
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Keith Randall <khr@golang.org>
The frontend rewriting lowers them to runtime calls on 386. It
matches explicitly uint32, but missed uint.
Fixes#16738.
Change-Id: Iece7a45edf74615baca052a53273c208f057636d
Reviewed-on: https://go-review.googlesource.com/27085
Run-TryBot: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
We already inlined
_, ok = e.(T)
_, ok = i.(E)
_, ok = e.(E)
The only ok-only variants not inlined are now
_, ok = i.(I)
_, ok = e.(I)
These call getitab, so are non-trivial.
Change-Id: Ie45fd8933ee179a679b92ce925079b94cff0ee12
Reviewed-on: https://go-review.googlesource.com/26658
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
CL 23393 introduces PAUTOHEAP, and access of PAUTOHEAP variable is
rewritten to indirection of a PAUTO variable. Mark this variable
non-nil, so this indirection does not introduce extra nil checks.
Change-Id: I31853eed5e60238b6c5bc0546e2e9ab340dcddd9
Reviewed-on: https://go-review.googlesource.com/26831
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
Add more ARM64 optimizations:
- use hardware zero register when it is possible.
- use shifted ops.
The assembler supports shifted ops but not documented, nor knows
how to print it. This CL adds them.
- enable fast division.
This was disabled because it makes the old backend generate slower
code. But with SSA it generates faster code.
Turn on SSA by default, also adjust tests.
Change-Id: I7794479954c83bb65008dcb457bc1e21d7496da6
Reviewed-on: https://go-review.googlesource.com/26950
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
GOARCH=386 SSATEST=1 ./all.bash passes
Caveat: still needs changes to test/ files to use *_ssa.go versions. I
won't check those changes in with this CL because the builders will
complain as they don't have SSATEST=1.
Mostly minor fixes.
Implement float <-> uint32 in assembly. It seems the simplest option
for now.
GO386=387 does not work. That's why I can't make SSA the default for
386 yet.
Change-Id: Ic4d4402104d32bcfb1fd612f5bb6539f9acb8ae0
Reviewed-on: https://go-review.googlesource.com/25119
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Machine supports (or the runtime simulates in soft float mode)
(u)int32<->float conversions. The frontend rewrites int64<->float
conversions to call to runtime function.
For int64->float32 conversion, the frontend generates
. . AS u(100) l(10) tc(1)
. . . NAME-main.~r1 u(1) a(true) g(1) l(9) x(8+0) class(PPARAMOUT) f(1) float32
. . . CALLFUNC u(100) l(10) tc(1) float32
. . . . NAME-runtime.int64tofloat64 u(1) a(true) x(0+0) class(PFUNC) tc(1) used(true) FUNC-func(int64) float64
The CALLFUNC node has type float32, whereas runtime.int64tofloat64
returns float64. The legacy backend implicitly makes a float64->float32
conversion. The SSA backend does not do implicit conversion, so we
insert an explicit CONV here.
All cmd/compile/internal/gc/testdata/*_ssa.go tests passed.
Progress on SSA for ARM. Still not complete.
Update #15365.
Change-Id: I30937c8ff977271246b068f48224693776804339
Reviewed-on: https://go-review.googlesource.com/23652
Reviewed-by: Keith Randall <khr@golang.org>
The main check here is that liveness now crashes if it finds an instruction
using a variable that should be tracked but is not.
Comments and adjustments in nodarg to explain what's going on and
to remove the "-1" argument added a few months ago, plus a sketch
of a future simplification.
The need for n.Orig in the earlier CL seems to have been an intermediate
problem rather than fundamental: the new explanations in nodarg make
clear that nodarg is not causing the problem I thought, and in fact now
using n instead of n.Orig works fine in plive.go.
Change-Id: I3f5cf9f6e4438a6d27abac7d490e7521545cd552
Reviewed-on: https://go-review.googlesource.com/23450
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
As in the elimination of PHEAP|PPARAM in CL 23393,
this is something the front end can trivially take care of
and then not bother the back ends with.
It also eliminates some suspect (and only lightly exercised)
code paths in the back ends.
I don't have a smoking gun for this one but it seems
more clearly correct.
Change-Id: I3b3f5e669b3b81d091ff1e2fb13226a6f14c69d5
Reviewed-on: https://go-review.googlesource.com/23431
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
The liveness computation of parameters generally was never
correct, but forcing all parameters to be live throughout the
function covered up that problem. The new SSA back end is
too clever: even though it currently keeps the parameter values live
throughout the function, it may find optimizations that mean
the current values are not written back to the original parameter
stack slots immediately or ever (for example if a parameter is set
to nil, SSA constant propagation may replace all later uses of the
parameter with a constant nil, eliminating the need to write the nil
value back to the stack slot), so the liveness code must now
track the actual operations on the stack slots, exposing these
problems.
One small problem in the handling of arguments is that nodarg
can return ONAME PPARAM nodes with adjusted offsets, so that
there are actually multiple *Node pointers for the same parameter
in the instruction stream. This might be possible to correct, but
not in this CL. For now, we fix this by using n.Orig instead of n
when considering PPARAM and PPARAMOUT nodes.
The major problem in the handling of arguments is general
confusion in the liveness code about the meaning of PPARAM|PHEAP
and PPARAMOUT|PHEAP nodes, especially as contrasted with PAUTO|PHEAP.
The difference between these two is that when a local variable "moves"
to the heap, it's really just allocated there to start with; in contrast,
when an argument moves to the heap, the actual data has to be copied
there from the stack at the beginning of the function, and when a
result "moves" to the heap the value in the heap has to be copied
back to the stack when the function returns
This general confusion is also present in the SSA back end.
The PHEAP bit worked decently when I first introduced it 7 years ago (!)
in 391425ae. The back end did nothing sophisticated, and in particular
there was no analysis at all: no escape analysis, no liveness analysis,
and certainly no SSA back end. But the complications caused in the
various downstream consumers suggest that this should be a detail
kept mainly in the front end.
This CL therefore eliminates both the PHEAP bit and even the idea of
"heap variables" from the back ends.
First, it replaces the PPARAM|PHEAP, PPARAMOUT|PHEAP, and PAUTO|PHEAP
variable classes with the single PAUTOHEAP, a pseudo-class indicating
a variable maintained on the heap and available by indirecting a
local variable kept on the stack (a plain PAUTO).
Second, walkexpr replaces all references to PAUTOHEAP variables
with indirections of the corresponding PAUTO variable.
The back ends and the liveness code now just see plain indirected
variables. This may actually produce better code, but the real goal
here is to eliminate these little-used and somewhat suspect code
paths in the back end analyses.
The OPARAM node type goes away too.
A followup CL will do the same to PPARAMREF. I'm not sure that
the back ends (SSA in particular) are handling those right either,
and with the framework established in this CL that change is trivial
and the result clearly more correct.
Fixes#15747.
Change-Id: I2770b1ce3cbc93981bfc7166be66a9da12013d74
Reviewed-on: https://go-review.googlesource.com/23393
Reviewed-by: Keith Randall <khr@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Updates #15462
Unexport Jconv, Sconv, Fconv, Hconv, Bconv, and VConv as they are
not referenced outside internal/gc.
Econv was only called by EType.String, so merge it into that method.
Change-Id: Iad9b06078eb513b85a03a43cd9eb9366477643d1
Reviewed-on: https://go-review.googlesource.com/22531
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Updates #15462
Replace all use of oconv(op, FmtSharp) with fmt.Printf("%#v", op).
This removes all the callers of oconv.
Change-Id: Ic3bf22495147f8497c8bada01d681428e2405b0e
Reviewed-on: https://go-review.googlesource.com/22530
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Updates #15462
Automatic refactor with sed -e.
Replace all oconv(op, 0) to string conversion with the raw op value
which fmt's %v verb can print directly.
The remaining oconv(op, FmtSharp) will be replaced with op.GoString and
%#v in the next CL.
Change-Id: I5e2f7ee0bd35caa65c6dd6cb1a866b5e4519e641
Reviewed-on: https://go-review.googlesource.com/22499
Run-TryBot: Dave Cheney <dave@cheney.net>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
