b92d39ef69
The standard sort swap method
func (t T) Swap(i, j int) {
t[i], t[j] = t[j], t[i]
}
uses no stack space on architectures for which
FixedFrameSize == 0, currently 386 and amd64.
Nevertheless, we insert a stack check prologue.
This is because it contains a call to
runtime.panicindex.
However, for a few common runtime functions,
we know at compile time that they require
no arguments. Allow them to pass unnoticed.
Triggers for 380 functions during make.bash.
Cuts 4k off cmd/go.
encoding/binary benchmarks:
ReadSlice1000Int32s-8 9.49µs ± 3% 9.41µs ± 5% ~ (p=0.075 n=29+27)
ReadStruct-8 1.50µs ± 3% 1.48µs ± 2% -1.49% (p=0.000 n=30+28)
ReadInts-8 599ns ± 3% 600ns ± 3% ~ (p=0.471 n=30+29)
WriteInts-8 836ns ± 4% 841ns ± 3% ~ (p=0.371 n=30+29)
WriteSlice1000Int32s-8 8.84µs ± 3% 8.69µs ± 5% -1.71% (p=0.001 n=30+30)
PutUvarint32-8 29.6ns ± 1% 28.1ns ± 3% -5.21% (p=0.000 n=28+28)
PutUvarint64-8 82.6ns ± 5% 82.3ns ±10% -0.43% (p=0.014 n=27+30)
Swap assembly before:
"".T.Swap t=1 size=74 args=0x28 locals=0x0
0x0000 00000 (swap.go:5) TEXT "".T.Swap(SB), $0-40
0x0000 00000 (swap.go:5) MOVQ (TLS), CX
0x0009 00009 (swap.go:5) CMPQ SP, 16(CX)
0x000d 00013 (swap.go:5) JLS 67
0x000f 00015 (swap.go:5) FUNCDATA $0, gclocals·3cadd97b66f25a3a642be35e9362338f(SB)
0x000f 00015 (swap.go:5) FUNCDATA $1, gclocals·69c1753bd5f81501d95132d08af04464(SB)
0x000f 00015 (swap.go:5) MOVQ "".i+32(FP), AX
0x0014 00020 (swap.go:5) MOVQ "".t+16(FP), CX
0x0019 00025 (swap.go:5) CMPQ AX, CX
0x001c 00028 (swap.go:5) JCC $0, 60
0x001e 00030 (swap.go:5) MOVQ "".t+8(FP), DX
0x0023 00035 (swap.go:5) MOVBLZX (DX)(AX*1), BX
0x0027 00039 (swap.go:5) MOVQ "".j+40(FP), SI
0x002c 00044 (swap.go:5) CMPQ SI, CX
0x002f 00047 (swap.go:5) JCC $0, 60
0x0031 00049 (swap.go:5) MOVBLZX (DX)(SI*1), CX
0x0035 00053 (swap.go:5) MOVB CL, (DX)(AX*1)
0x0038 00056 (swap.go:5) MOVB BL, (DX)(SI*1)
0x003b 00059 (swap.go:5) RET
0x003c 00060 (swap.go:5) PCDATA $0, $1
0x003c 00060 (swap.go:5) CALL runtime.panicindex(SB)
0x0041 00065 (swap.go:5) UNDEF
0x0043 00067 (swap.go:5) NOP
0x0043 00067 (swap.go:5) CALL runtime.morestack_noctxt(SB)
0x0048 00072 (swap.go:5) JMP 0
Swap assembly after:
"".T.Swap t=1 size=52 args=0x28 locals=0x0
0x0000 00000 (swap.go:5) TEXT "".T.Swap(SB), $0-40
0x0000 00000 (swap.go:5) FUNCDATA $0, gclocals·3cadd97b66f25a3a642be35e9362338f(SB)
0x0000 00000 (swap.go:5) FUNCDATA $1, gclocals·69c1753bd5f81501d95132d08af04464(SB)
0x0000 00000 (swap.go:5) MOVQ "".i+32(FP), AX
0x0005 00005 (swap.go:5) MOVQ "".t+16(FP), CX
0x000a 00010 (swap.go:5) CMPQ AX, CX
0x000d 00013 (swap.go:5) JCC $0, 45
0x000f 00015 (swap.go:5) MOVQ "".t+8(FP), DX
0x0014 00020 (swap.go:5) MOVBLZX (DX)(AX*1), BX
0x0018 00024 (swap.go:5) MOVQ "".j+40(FP), SI
0x001d 00029 (swap.go:5) CMPQ SI, CX
0x0020 00032 (swap.go:5) JCC $0, 45
0x0022 00034 (swap.go:5) MOVBLZX (DX)(SI*1), CX
0x0026 00038 (swap.go:5) MOVB CL, (DX)(AX*1)
0x0029 00041 (swap.go:5) MOVB BL, (DX)(SI*1)
0x002c 00044 (swap.go:5) RET
0x002d 00045 (swap.go:5) PCDATA $0, $1
0x002d 00045 (swap.go:5) CALL runtime.panicindex(SB)
0x0032 00050 (swap.go:5) UNDEF
Change-Id: I57dad14af8aaa5e6112deac407cfadc2bfaf1f54
Reviewed-on: https://go-review.googlesource.com/24814
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
|
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|---|---|---|
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| doc | ||
| lib/time | ||
| misc | ||
| src | ||
| test | ||
| .gitattributes | ||
| .gitignore | ||
| AUTHORS | ||
| CONTRIBUTING.md | ||
| CONTRIBUTORS | ||
| favicon.ico | ||
| LICENSE | ||
| PATENTS | ||
| README.md | ||
| robots.txt | ||
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--
Binary Distribution Notes
If you have just untarred a binary Go distribution, you need to set the environment variable $GOROOT to the full path of the go directory (the one containing this file). You can omit the variable if you unpack it into /usr/local/go, or if you rebuild from sources by running all.bash (see doc/install-source.html). You should also add the Go binary directory $GOROOT/bin to your shell's path.
For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile:
export GOROOT=$HOME/go
export PATH=$PATH:$GOROOT/bin
See https://golang.org/doc/install or doc/install.html for more details.