1 // Copyright 2014 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // This file contains tests for the suspicious shift checker. 6 7 package testdata 8 9 import ( 10 "fmt" 11 "unsafe" 12 ) 13 14 func ShiftTest() { 15 var i8 int8 16 _ = i8 << 7 17 _ = (i8 + 1) << 8 // ERROR ".i8 . 1. .8 bits. too small for shift of 8" 18 _ = i8 << (7 + 1) // ERROR "i8 .8 bits. too small for shift of 8" 19 _ = i8 >> 8 // ERROR "i8 .8 bits. too small for shift of 8" 20 i8 <<= 8 // ERROR "i8 .8 bits. too small for shift of 8" 21 i8 >>= 8 // ERROR "i8 .8 bits. too small for shift of 8" 22 var i16 int16 23 _ = i16 << 15 24 _ = i16 << 16 // ERROR "i16 .16 bits. too small for shift of 16" 25 _ = i16 >> 16 // ERROR "i16 .16 bits. too small for shift of 16" 26 i16 <<= 16 // ERROR "i16 .16 bits. too small for shift of 16" 27 i16 >>= 16 // ERROR "i16 .16 bits. too small for shift of 16" 28 var i32 int32 29 _ = i32 << 31 30 _ = i32 << 32 // ERROR "i32 .32 bits. too small for shift of 32" 31 _ = i32 >> 32 // ERROR "i32 .32 bits. too small for shift of 32" 32 i32 <<= 32 // ERROR "i32 .32 bits. too small for shift of 32" 33 i32 >>= 32 // ERROR "i32 .32 bits. too small for shift of 32" 34 var i64 int64 35 _ = i64 << 63 36 _ = i64 << 64 // ERROR "i64 .64 bits. too small for shift of 64" 37 _ = i64 >> 64 // ERROR "i64 .64 bits. too small for shift of 64" 38 i64 <<= 64 // ERROR "i64 .64 bits. too small for shift of 64" 39 i64 >>= 64 // ERROR "i64 .64 bits. too small for shift of 64" 40 var u8 uint8 41 _ = u8 << 7 42 _ = u8 << 8 // ERROR "u8 .8 bits. too small for shift of 8" 43 _ = u8 >> 8 // ERROR "u8 .8 bits. too small for shift of 8" 44 u8 <<= 8 // ERROR "u8 .8 bits. too small for shift of 8" 45 u8 >>= 8 // ERROR "u8 .8 bits. too small for shift of 8" 46 var u16 uint16 47 _ = u16 << 15 48 _ = u16 << 16 // ERROR "u16 .16 bits. too small for shift of 16" 49 _ = u16 >> 16 // ERROR "u16 .16 bits. too small for shift of 16" 50 u16 <<= 16 // ERROR "u16 .16 bits. too small for shift of 16" 51 u16 >>= 16 // ERROR "u16 .16 bits. too small for shift of 16" 52 var u32 uint32 53 _ = u32 << 31 54 _ = u32 << 32 // ERROR "u32 .32 bits. too small for shift of 32" 55 _ = u32 >> 32 // ERROR "u32 .32 bits. too small for shift of 32" 56 u32 <<= 32 // ERROR "u32 .32 bits. too small for shift of 32" 57 u32 >>= 32 // ERROR "u32 .32 bits. too small for shift of 32" 58 var u64 uint64 59 _ = u64 << 63 60 _ = u64 << 64 // ERROR "u64 .64 bits. too small for shift of 64" 61 _ = u64 >> 64 // ERROR "u64 .64 bits. too small for shift of 64" 62 u64 <<= 64 // ERROR "u64 .64 bits. too small for shift of 64" 63 u64 >>= 64 // ERROR "u64 .64 bits. too small for shift of 64" 64 _ = u64 << u64 // Non-constant shifts should succeed. 65 66 var i int 67 _ = i << 31 68 const in = 8 * unsafe.Sizeof(i) 69 _ = i << in // ERROR "too small for shift" 70 _ = i >> in // ERROR "too small for shift" 71 i <<= in // ERROR "too small for shift" 72 i >>= in // ERROR "too small for shift" 73 const ix = 8*unsafe.Sizeof(i) - 1 74 _ = i << ix 75 _ = i >> ix 76 i <<= ix 77 i >>= ix 78 79 var u uint 80 _ = u << 31 81 const un = 8 * unsafe.Sizeof(u) 82 _ = u << un // ERROR "too small for shift" 83 _ = u >> un // ERROR "too small for shift" 84 u <<= un // ERROR "too small for shift" 85 u >>= un // ERROR "too small for shift" 86 const ux = 8*unsafe.Sizeof(u) - 1 87 _ = u << ux 88 _ = u >> ux 89 u <<= ux 90 u >>= ux 91 92 var p uintptr 93 _ = p << 31 94 const pn = 8 * unsafe.Sizeof(p) 95 _ = p << pn // ERROR "too small for shift" 96 _ = p >> pn // ERROR "too small for shift" 97 p <<= pn // ERROR "too small for shift" 98 p >>= pn // ERROR "too small for shift" 99 const px = 8*unsafe.Sizeof(p) - 1 100 _ = p << px 101 _ = p >> px 102 p <<= px 103 p >>= px 104 105 const oneIf64Bit = ^uint(0) >> 63 // allow large shifts of constants; they are used for 32/64 bit compatibility tricks 106 107 var h uintptr 108 h = h<<8 | (h >> (8 * (unsafe.Sizeof(h) - 1))) 109 h <<= 8 * unsafe.Sizeof(h) // ERROR "too small for shift" 110 h >>= 7 * unsafe.Alignof(h) 111 h >>= 8 * unsafe.Alignof(h) // ERROR "too small for shift" 112 } 113 114 func ShiftDeadCode() { 115 var i int 116 const iBits = 8 * unsafe.Sizeof(i) 117 118 if iBits <= 32 { 119 if iBits == 16 { 120 _ = i >> 8 121 } else { 122 _ = i >> 16 123 } 124 } else { 125 _ = i >> 32 126 } 127 128 if iBits >= 64 { 129 _ = i << 32 130 if iBits == 128 { 131 _ = i << 64 132 } 133 } else { 134 _ = i << 16 135 } 136 137 if iBits == 64 { 138 _ = i << 32 139 } 140 141 switch iBits { 142 case 128, 64: 143 _ = i << 32 144 default: 145 _ = i << 16 146 } 147 148 switch { 149 case iBits < 32: 150 _ = i << 16 151 case iBits > 64: 152 _ = i << 64 153 default: 154 _ = i << 64 // ERROR "too small for shift" 155 } 156 157 // Make sure other vet checks work in dead code. 158 if iBits == 1024 { 159 _ = i << 512 // OK 160 fmt.Printf("foo %s bar", 123) // ERROR "Printf" 161 } 162 } 163
