1 // Copyright 2015 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 package main 6 7 import ( 8 "bytes" 9 "fmt" 10 "go/format" 11 "io/ioutil" 12 "log" 13 ) 14 15 // This program generates tests to verify that zeroing operations 16 // zero the data they are supposed to and clobber no adjacent values. 17 18 // run as `go run zeroGen.go`. A file called zero.go 19 // will be written into the parent directory containing the tests. 20 21 var sizes = [...]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 16, 17, 23, 24, 25, 31, 32, 33, 63, 64, 65, 1023, 1024, 1025} 22 23 func main() { 24 w := new(bytes.Buffer) 25 fmt.Fprintf(w, "// run\n") 26 fmt.Fprintf(w, "// autogenerated from gen/zeroGen.go - do not edit!\n") 27 fmt.Fprintf(w, "package main\n") 28 fmt.Fprintf(w, "import \"fmt\"\n") 29 30 for _, s := range sizes { 31 // type for test 32 fmt.Fprintf(w, "type T%d struct {\n", s) 33 fmt.Fprintf(w, " pre [8]byte\n") 34 fmt.Fprintf(w, " mid [%d]byte\n", s) 35 fmt.Fprintf(w, " post [8]byte\n") 36 fmt.Fprintf(w, "}\n") 37 38 // function being tested 39 fmt.Fprintf(w, "func zero%d_ssa(x *[%d]byte) {\n", s, s) 40 fmt.Fprintf(w, " switch{}\n") 41 fmt.Fprintf(w, " *x = [%d]byte{}\n", s) 42 fmt.Fprintf(w, "}\n") 43 44 // testing harness 45 fmt.Fprintf(w, "func testZero%d() {\n", s) 46 fmt.Fprintf(w, " a := T%d{[8]byte{255,255,255,255,255,255,255,255},[%d]byte{", s, s) 47 for i := 0; i < s; i++ { 48 fmt.Fprintf(w, "255,") 49 } 50 fmt.Fprintf(w, "},[8]byte{255,255,255,255,255,255,255,255}}\n") 51 fmt.Fprintf(w, " zero%d_ssa(&a.mid)\n", s) 52 fmt.Fprintf(w, " want := T%d{[8]byte{255,255,255,255,255,255,255,255},[%d]byte{", s, s) 53 for i := 0; i < s; i++ { 54 fmt.Fprintf(w, "0,") 55 } 56 fmt.Fprintf(w, "},[8]byte{255,255,255,255,255,255,255,255}}\n") 57 fmt.Fprintf(w, " if a != want {\n") 58 fmt.Fprintf(w, " fmt.Printf(\"zero%d got=%%v, want %%v\\n\", a, want)\n", s) 59 fmt.Fprintf(w, " failed=true\n") 60 fmt.Fprintf(w, " }\n") 61 fmt.Fprintf(w, "}\n") 62 } 63 64 // boilerplate at end 65 fmt.Fprintf(w, "var failed bool\n") 66 fmt.Fprintf(w, "func main() {\n") 67 for _, s := range sizes { 68 fmt.Fprintf(w, " testZero%d()\n", s) 69 } 70 fmt.Fprintf(w, " if failed {\n") 71 fmt.Fprintf(w, " panic(\"failed\")\n") 72 fmt.Fprintf(w, " }\n") 73 fmt.Fprintf(w, "}\n") 74 75 // gofmt result 76 b := w.Bytes() 77 src, err := format.Source(b) 78 if err != nil { 79 fmt.Printf("%s\n", b) 80 panic(err) 81 } 82 83 // write to file 84 err = ioutil.WriteFile("../zero.go", src, 0666) 85 if err != nil { 86 log.Fatalf("can't write output: %v\n", err) 87 } 88 } 89
