1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
// Copyright 2017 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.
// This program generates a test to verify that the standard comparison
// operators properly handle one const operand. The test file should be
// generated with a known working version of go.
// launch with `go run cmpConstGen.go` a file called cmpConst.go
// will be written into the parent directory containing the tests
package main
import (
"bytes"
"fmt"
"go/format"
"io/ioutil"
"log"
"math/big"
"sort"
)
const (
maxU64 = (1 << 64) - 1
maxU32 = (1 << 32) - 1
maxU16 = (1 << 16) - 1
maxU8 = (1 << 8) - 1
maxI64 = (1 << 63) - 1
maxI32 = (1 << 31) - 1
maxI16 = (1 << 15) - 1
maxI8 = (1 << 7) - 1
minI64 = -(1 << 63)
minI32 = -(1 << 31)
minI16 = -(1 << 15)
minI8 = -(1 << 7)
)
func cmp(left *big.Int, op string, right *big.Int) bool {
switch left.Cmp(right) {
case -1: // less than
return op == "<" || op == "<=" || op == "!="
case 0: // equal
return op == "==" || op == "<=" || op == ">="
case 1: // greater than
return op == ">" || op == ">=" || op == "!="
}
panic("unexpected comparison value")
}
func inRange(typ string, val *big.Int) bool {
min, max := &big.Int{}, &big.Int{}
switch typ {
case "uint64":
max = max.SetUint64(maxU64)
case "uint32":
max = max.SetUint64(maxU32)
case "uint16":
max = max.SetUint64(maxU16)
case "uint8":
max = max.SetUint64(maxU8)
case "int64":
min = min.SetInt64(minI64)
max = max.SetInt64(maxI64)
case "int32":
min = min.SetInt64(minI32)
max = max.SetInt64(maxI32)
case "int16":
min = min.SetInt64(minI16)
max = max.SetInt64(maxI16)
case "int8":
min = min.SetInt64(minI8)
max = max.SetInt64(maxI8)
default:
panic("unexpected type")
}
return cmp(min, "<=", val) && cmp(val, "<=", max)
}
func getValues(typ string) []*big.Int {
Uint := func(v uint64) *big.Int { return big.NewInt(0).SetUint64(v) }
Int := func(v int64) *big.Int { return big.NewInt(0).SetInt64(v) }
values := []*big.Int{
// limits
Uint(maxU64),
Uint(maxU64 - 1),
Uint(maxI64 + 1),
Uint(maxI64),
Uint(maxI64 - 1),
Uint(maxU32 + 1),
Uint(maxU32),
Uint(maxU32 - 1),
Uint(maxI32 + 1),
Uint(maxI32),
Uint(maxI32 - 1),
Uint(maxU16 + 1),
Uint(maxU16),
Uint(maxU16 - 1),
Uint(maxI16 + 1),
Uint(maxI16),
Uint(maxI16 - 1),
Uint(maxU8 + 1),
Uint(maxU8),
Uint(maxU8 - 1),
Uint(maxI8 + 1),
Uint(maxI8),
Uint(maxI8 - 1),
Uint(0),
Int(minI8 + 1),
Int(minI8),
Int(minI8 - 1),
Int(minI16 + 1),
Int(minI16),
Int(minI16 - 1),
Int(minI32 + 1),
Int(minI32),
Int(minI32 - 1),
Int(minI64 + 1),
Int(minI64),
// other possibly interesting values
Uint(1),
Int(-1),
Uint(0xff << 56),
Uint(0xff << 32),
Uint(0xff << 24),
}
sort.Slice(values, func(i, j int) bool { return values[i].Cmp(values[j]) == -1 })
var ret []*big.Int
for _, val := range values {
if !inRange(typ, val) {
continue
}
ret = append(ret, val)
}
return ret
}
func sigString(v *big.Int) string {
var t big.Int
t.Abs(v)
if v.Sign() == -1 {
return "neg" + t.String()
}
return t.String()
}
func main() {
types := []string{
"uint64", "uint32", "uint16", "uint8",
"int64", "int32", "int16", "int8",
}
w := new(bytes.Buffer)
fmt.Fprintf(w, "// run\n")
fmt.Fprintf(w, "// Code generated by gen/cmpConstGen.go. DO NOT EDIT.\n\n")
fmt.Fprintf(w, "package main;\n")
fmt.Fprintf(w, "import (\"fmt\"; \"reflect\"; \"runtime\";)\n")
fmt.Fprintf(w, "// results show the expected result for the elements left of, equal to and right of the index.\n")
fmt.Fprintf(w, "type result struct{l, e, r bool}\n")
fmt.Fprintf(w, "var (\n")
fmt.Fprintf(w, " eq = result{l: false, e: true, r: false}\n")
fmt.Fprintf(w, " ne = result{l: true, e: false, r: true}\n")
fmt.Fprintf(w, " lt = result{l: true, e: false, r: false}\n")
fmt.Fprintf(w, " le = result{l: true, e: true, r: false}\n")
fmt.Fprintf(w, " gt = result{l: false, e: false, r: true}\n")
fmt.Fprintf(w, " ge = result{l: false, e: true, r: true}\n")
fmt.Fprintf(w, ")\n")
operators := []struct{ op, name string }{
{"<", "lt"},
{"<=", "le"},
{">", "gt"},
{">=", "ge"},
{"==", "eq"},
{"!=", "ne"},
}
for _, typ := range types {
// generate a slice containing valid values for this type
fmt.Fprintf(w, "\n// %v tests\n", typ)
values := getValues(typ)
fmt.Fprintf(w, "var %v_vals = []%v{\n", typ, typ)
for _, val := range values {
fmt.Fprintf(w, "%v,\n", val.String())
}
fmt.Fprintf(w, "}\n")
// generate test functions
for _, r := range values {
// TODO: could also test constant on lhs.
sig := sigString(r)
for _, op := range operators {
// no need for go:noinline because the function is called indirectly
fmt.Fprintf(w, "func %v_%v_%v(x %v) bool { return x %v %v; }\n", op.name, sig, typ, typ, op.op, r.String())
}
}
// generate a table of test cases
fmt.Fprintf(w, "var %v_tests = []struct{\n", typ)
fmt.Fprintf(w, " idx int // index of the constant used\n")
fmt.Fprintf(w, " exp result // expected results\n")
fmt.Fprintf(w, " fn func(%v) bool\n", typ)
fmt.Fprintf(w, "}{\n")
for i, r := range values {
sig := sigString(r)
for _, op := range operators {
fmt.Fprintf(w, "{idx: %v,", i)
fmt.Fprintf(w, "exp: %v,", op.name)
fmt.Fprintf(w, "fn: %v_%v_%v},\n", op.name, sig, typ)
}
}
fmt.Fprintf(w, "}\n")
}
// emit the main function, looping over all test cases
fmt.Fprintf(w, "func main() {\n")
for _, typ := range types {
fmt.Fprintf(w, "for i, test := range %v_tests {\n", typ)
fmt.Fprintf(w, " for j, x := range %v_vals {\n", typ)
fmt.Fprintf(w, " want := test.exp.l\n")
fmt.Fprintf(w, " if j == test.idx {\nwant = test.exp.e\n}")
fmt.Fprintf(w, " else if j > test.idx {\nwant = test.exp.r\n}\n")
fmt.Fprintf(w, " if test.fn(x) != want {\n")
fmt.Fprintf(w, " fn := runtime.FuncForPC(reflect.ValueOf(test.fn).Pointer()).Name()\n")
fmt.Fprintf(w, " msg := fmt.Sprintf(\"test failed: %%v(%%v) != %%v [type=%v i=%%v j=%%v idx=%%v]\", fn, x, want, i, j, test.idx)\n", typ)
fmt.Fprintf(w, " panic(msg)\n")
fmt.Fprintf(w, " }\n")
fmt.Fprintf(w, " }\n")
fmt.Fprintf(w, "}\n")
}
fmt.Fprintf(w, "}\n")
// gofmt result
b := w.Bytes()
src, err := format.Source(b)
if err != nil {
fmt.Printf("%s\n", b)
panic(err)
}
// write to file
err = ioutil.WriteFile("../cmpConst.go", src, 0666)
if err != nil {
log.Fatalf("can't write output: %v\n", err)
}
}
|
