diff options
Diffstat (limited to 'test/bounds.go')
| -rw-r--r-- | test/bounds.go | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/test/bounds.go b/test/bounds.go new file mode 100644 index 0000000..aa1d51b --- /dev/null +++ b/test/bounds.go @@ -0,0 +1,284 @@ +// errorcheck -0 -m -l + +// Copyright 2012 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +// Test, using compiler diagnostic flags, that bounds check elimination +// is eliminating the correct checks. + +package foo + +var ( + s []int + + a1 [1]int + a1k [1000]int + a100k [100000]int + + p1 *[1]int + p1k *[1000]int + p100k *[100000]int + + i int + ui uint + i8 int8 + ui8 uint8 + i16 int16 + ui16 uint16 + i32 int32 + ui32 uint32 + i64 int64 + ui64 uint64 +) + +func main() { + // Most things need checks. + use(s[i]) + use(a1[i]) + use(a1k[i]) + use(a100k[i]) + use(p1[i]) + use(p1k[i]) + use(p100k[i]) + + use(s[ui]) + use(a1[ui]) + use(a1k[ui]) + use(a100k[ui]) + use(p1[ui]) + use(p1k[ui]) + use(p100k[ui]) + + use(s[i8]) + use(a1[i8]) + use(a1k[i8]) + use(a100k[i8]) + use(p1[i8]) + use(p1k[i8]) + use(p100k[i8]) + + // Unsigned 8-bit numbers don't need checks for len >= 2⁸. + use(s[ui8]) + use(a1[ui8]) + use(a1k[ui8]) // ERROR "index bounds check elided" + use(a100k[ui8]) // ERROR "index bounds check elided" + use(p1[ui8]) + use(p1k[ui8]) // ERROR "index bounds check elided" + use(p100k[ui8]) // ERROR "index bounds check elided" + + use(s[i16]) + use(a1[i16]) + use(a1k[i16]) + use(a100k[i16]) + use(p1[i16]) + use(p1k[i16]) + use(p100k[i16]) + + // Unsigned 16-bit numbers don't need checks for len >= 2¹⁶. + use(s[ui16]) + use(a1[ui16]) + use(a1k[ui16]) + use(a100k[ui16]) // ERROR "index bounds check elided" + use(p1[ui16]) + use(p1k[ui16]) + use(p100k[ui16]) // ERROR "index bounds check elided" + + use(s[i32]) + use(a1[i32]) + use(a1k[i32]) + use(a100k[i32]) + use(p1[i32]) + use(p1k[i32]) + use(p100k[i32]) + + use(s[ui32]) + use(a1[ui32]) + use(a1k[ui32]) + use(a100k[ui32]) + use(p1[ui32]) + use(p1k[ui32]) + use(p100k[ui32]) + + use(s[i64]) + use(a1[i64]) + use(a1k[i64]) + use(a100k[i64]) + use(p1[i64]) + use(p1k[i64]) + use(p100k[i64]) + + use(s[ui64]) + use(a1[ui64]) + use(a1k[ui64]) + use(a100k[ui64]) + use(p1[ui64]) + use(p1k[ui64]) + use(p100k[ui64]) + + // Mod truncates the maximum value to one less than the argument, + // but signed mod can be negative, so only unsigned mod counts. + use(s[i%999]) + use(a1[i%999]) + use(a1k[i%999]) + use(a100k[i%999]) + use(p1[i%999]) + use(p1k[i%999]) + use(p100k[i%999]) + + use(s[ui%999]) + use(a1[ui%999]) + use(a1k[ui%999]) // ERROR "index bounds check elided" + use(a100k[ui%999]) // ERROR "index bounds check elided" + use(p1[ui%999]) + use(p1k[ui%999]) // ERROR "index bounds check elided" + use(p100k[ui%999]) // ERROR "index bounds check elided" + + use(s[i%1000]) + use(a1[i%1000]) + use(a1k[i%1000]) + use(a100k[i%1000]) + use(p1[i%1000]) + use(p1k[i%1000]) + use(p100k[i%1000]) + + use(s[ui%1000]) + use(a1[ui%1000]) + use(a1k[ui%1000]) // ERROR "index bounds check elided" + use(a100k[ui%1000]) // ERROR "index bounds check elided" + use(p1[ui%1000]) + use(p1k[ui%1000]) // ERROR "index bounds check elided" + use(p100k[ui%1000]) // ERROR "index bounds check elided" + + use(s[i%1001]) + use(a1[i%1001]) + use(a1k[i%1001]) + use(a100k[i%1001]) + use(p1[i%1001]) + use(p1k[i%1001]) + use(p100k[i%1001]) + + use(s[ui%1001]) + use(a1[ui%1001]) + use(a1k[ui%1001]) + use(a100k[ui%1001]) // ERROR "index bounds check elided" + use(p1[ui%1001]) + use(p1k[ui%1001]) + use(p100k[ui%1001]) // ERROR "index bounds check elided" + + // Bitwise and truncates the maximum value to the mask value. + // The result (for a positive mask) cannot be negative, so elision + // applies to both signed and unsigned indexes. + use(s[i&999]) + use(a1[i&999]) + use(a1k[i&999]) // ERROR "index bounds check elided" + use(a100k[i&999]) // ERROR "index bounds check elided" + use(p1[i&999]) + use(p1k[i&999]) // ERROR "index bounds check elided" + use(p100k[i&999]) // ERROR "index bounds check elided" + + use(s[ui&999]) + use(a1[ui&999]) + use(a1k[ui&999]) // ERROR "index bounds check elided" + use(a100k[ui&999]) // ERROR "index bounds check elided" + use(p1[ui&999]) + use(p1k[ui&999]) // ERROR "index bounds check elided" + use(p100k[ui&999]) // ERROR "index bounds check elided" + + use(s[i&1000]) + use(a1[i&1000]) + use(a1k[i&1000]) + use(a100k[i&1000]) // ERROR "index bounds check elided" + use(p1[i&1000]) + use(p1k[i&1000]) + use(p100k[i&1000]) // ERROR "index bounds check elided" + + use(s[ui&1000]) + use(a1[ui&1000]) + use(a1k[ui&1000]) + use(a100k[ui&1000]) // ERROR "index bounds check elided" + use(p1[ui&1000]) + use(p1k[ui&1000]) + use(p100k[ui&1000]) // ERROR "index bounds check elided" + + use(a1[i&^-1]) // ERROR "index bounds check elided" + use(a1[i&^0]) + use(a1[i&^-2]) + use(a1[i&^1]) + use(a1k[i&^-1]) // ERROR "index bounds check elided" + use(a1k[i&^0]) + use(a1k[i&^-2]) // ERROR "index bounds check elided" + use(a1k[i&^1]) + use(a1k[i8&^0]) + use(a1k[i8&^-128]) // ERROR "index bounds check elided" + use(a1k[ui8&^1]) // ERROR "index bounds check elided" + use(a1k[ui16&^0xf000]) + use(a1k[ui16&^0xff00]) // ERROR "index bounds check elided" + + // Right shift cuts the effective number of bits in the index, + // but only for unsigned (signed stays negative). + use(s[i32>>22]) + use(a1[i32>>22]) + use(a1k[i32>>22]) + use(a100k[i32>>22]) + use(p1[i32>>22]) + use(p1k[i32>>22]) + use(p100k[i32>>22]) + + use(s[ui32>>22]) + use(a1[ui32>>22]) + use(a1k[ui32>>22]) + use(a100k[ui32>>22]) // ERROR "index bounds check elided" + use(p1[ui32>>22]) + use(p1k[ui32>>22]) + use(p100k[ui32>>22]) // ERROR "index bounds check elided" + + use(s[i32>>23]) + use(a1[i32>>23]) + use(a1k[i32>>23]) + use(a100k[i32>>23]) + use(p1[i32>>23]) + use(p1k[i32>>23]) + use(p100k[i32>>23]) + + use(s[ui32>>23]) + use(a1[ui32>>23]) + use(a1k[ui32>>23]) // ERROR "index bounds check elided" + use(a100k[ui32>>23]) // ERROR "index bounds check elided" + use(p1[ui32>>23]) + use(p1k[ui32>>23]) // ERROR "index bounds check elided" + use(p100k[ui32>>23]) // ERROR "index bounds check elided" + + // Division cuts the range like right shift does. + use(s[i/1e6]) + use(a1[i/1e6]) + use(a1k[i/1e6]) + use(a100k[i/1e6]) + use(p1[i/1e6]) + use(p1k[i/1e6]) + use(p100k[i/1e6]) + + use(s[ui/1e6]) + use(a1[ui/1e6]) + use(a1k[ui/1e6]) + use(p1[ui/1e6]) + use(p1k[ui/1e6]) + + use(s[i/1e7]) + use(a1[i/1e7]) + use(a1k[i/1e7]) + use(a100k[i/1e7]) + use(p1[i/1e7]) + use(p1k[i/1e7]) + use(p100k[i/1e7]) + + use(s[ui/1e7]) + use(a1[ui/1e7]) + use(p1[ui/1e7]) +} + +var sum int + +func use(x int) { + sum += x +} |