Stowage/go
2
0
Fork 0
mirror of https://github.com/golang/go.git synced 2025-12-08 06:10:04 +00:00
Code Issues Projects Releases Packages Wiki Activity

strings: fix Contains on amd64

Browse source 
The 17-31 byte code is broken.  Disabled it.

Added a bunch of tests to at least cover the cases
in indexShortStr.  I'll channel Brad and wonder why
this CL ever got in without any tests.

Fixes #15679

Change-Id: I84a7b283a74107db865b9586c955dcf5f2d60161
Reviewed-on: https://go-review.googlesource.com/23106
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Keith Randall 2016-05-14 17:33:23 -07:00
parent aba7b3e91c
commit 0bc14f57ec
3 changed files with 66 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

1
src/runtime/asm_amd64.s
View file

@ -1800,6 +1800,7 @@ loop16:
CMPQ DI,DX
JB loop16
JMP fail
//TODO: the code below is wrong. Fix it. See #15679.
_17_to_31:
LEAQ 1(DI)(DX*1), DX
SUBQ AX, DX

2
src/strings/strings_amd64.go
View file

@ -7,7 +7,7 @@ package strings
// indexShortStr returns the index of the first instance of c in s, or -1 if c is not present in s.
// indexShortStr requires 2 <= len(c) <= shortStringLen
func indexShortStr(s, c string) int // ../runtime/asm_$GOARCH.s
const shortStringLen = 31
const shortStringLen = 16 // TODO: restore to 31 when #15679 is fixed
// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
func Index(s, sep string) int {

64
src/strings/strings_test.go
View file

@ -1036,6 +1036,70 @@ var ContainsTests = []struct {
{"abc", "bcd", false},
{"abc", "", true},
{"", "a", false},
// cases to cover code in runtime/asm_amd64.s:indexShortStr
// 2-byte needle
{"xxxxxx", "01", false},
{"01xxxx", "01", true},
{"xx01xx", "01", true},
{"xxxx01", "01", true},
{"01xxxxx"[1:], "01", false},
{"xxxxx01"[:6], "01", false},
// 3-byte needle
{"xxxxxxx", "012", false},
{"012xxxx", "012", true},
{"xx012xx", "012", true},
{"xxxx012", "012", true},
{"012xxxxx"[1:], "012", false},
{"xxxxx012"[:7], "012", false},
// 4-byte needle
{"xxxxxxxx", "0123", false},
{"0123xxxx", "0123", true},
{"xx0123xx", "0123", true},
{"xxxx0123", "0123", true},
{"0123xxxxx"[1:], "0123", false},
{"xxxxx0123"[:8], "0123", false},
// 5-7-byte needle
{"xxxxxxxxx", "01234", false},
{"01234xxxx", "01234", true},
{"xx01234xx", "01234", true},
{"xxxx01234", "01234", true},
{"01234xxxxx"[1:], "01234", false},
{"xxxxx01234"[:9], "01234", false},
// 8-byte needle
{"xxxxxxxxxxxx", "01234567", false},
{"01234567xxxx", "01234567", true},
{"xx01234567xx", "01234567", true},
{"xxxx01234567", "01234567", true},
{"01234567xxxxx"[1:], "01234567", false},
{"xxxxx01234567"[:12], "01234567", false},
// 9-15-byte needle
{"xxxxxxxxxxxxx", "012345678", false},
{"012345678xxxx", "012345678", true},
{"xx012345678xx", "012345678", true},
{"xxxx012345678", "012345678", true},
{"012345678xxxxx"[1:], "012345678", false},
{"xxxxx012345678"[:13], "012345678", false},
// 16-byte needle
{"xxxxxxxxxxxxxxxxxxxx", "0123456789ABCDEF", false},
{"0123456789ABCDEFxxxx", "0123456789ABCDEF", true},
{"xx0123456789ABCDEFxx", "0123456789ABCDEF", true},
{"xxxx0123456789ABCDEF", "0123456789ABCDEF", true},
{"0123456789ABCDEFxxxxx"[1:], "0123456789ABCDEF", false},
{"xxxxx0123456789ABCDEF"[:20], "0123456789ABCDEF", false},
// 17-31-byte needle
{"xxxxxxxxxxxxxxxxxxxxx", "0123456789ABCDEFG", false},
{"0123456789ABCDEFGxxxx", "0123456789ABCDEFG", true},
{"xx0123456789ABCDEFGxx", "0123456789ABCDEFG", true},
{"xxxx0123456789ABCDEFG", "0123456789ABCDEFG", true},
{"0123456789ABCDEFGxxxxx"[1:], "0123456789ABCDEFG", false},
{"xxxxx0123456789ABCDEFG"[:21], "0123456789ABCDEFG", false},
// partial match cases
{"xx01x", "012", false}, // 3
{"xx0123x", "01234", false}, // 5-7
{"xx01234567x", "012345678", false}, // 9-15
{"xx0123456789ABCDEFx", "0123456789ABCDEFG", false}, // 17-31, issue 15679
}
func TestContains(t *testing.T) {