bug449.go

     1  // runoutput
     2  
     3  // Copyright 2012 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // Issue 3866
     8  // runtime.equal failed to take padding between arguments and
     9  // return values into account, so in certain cases gc-generated
    10  // code will read a random bool from the stack as the result of
    11  // the comparison.
    12  // This program generates a lot of equality tests and hopes to
    13  // catch this.
    14  // NOTE: this program assumes comparing instance of T and T's
    15  // underlying []byte will make gc emit calls to runtime.equal,
    16  // and if gc optimizes this case, then the test will no longer
    17  // be correct (in the sense that it no longer tests runtime.equal).
    18  
    19  package main
    20  
    21  import (
    22  	"bytes"
    23  	"fmt"
    24  	"strconv"
    25  	"strings"
    26  )
    27  
    28  const ntest = 1024
    29  
    30  func main() {
    31  	var decls, calls bytes.Buffer
    32  
    33  	for i := 1; i <= ntest; i++ {
    34  		s := strconv.Itoa(i)
    35  		decls.WriteString(strings.Replace(decl, "$", s, -1))
    36  		calls.WriteString(strings.Replace("call(test$)\n\t", "$", s, -1))
    37  	}
    38  
    39  	program = strings.Replace(program, "$DECLS", decls.String(), 1)
    40  	program = strings.Replace(program, "$CALLS", calls.String(), 1)
    41  	fmt.Print(program)
    42  }
    43  
    44  var program = `package main
    45  
    46  var count int
    47  
    48  func call(f func() bool) {
    49  	if f() {
    50  		count++
    51  	}
    52  }
    53  
    54  $DECLS
    55  
    56  func main() {
    57  	$CALLS
    58  	if count != 0 {
    59  		println("failed", count, "case(s)")
    60  	}
    61  }
    62  `
    63  
    64  const decl = `
    65  type T$ [$]uint8
    66  func test$() bool {
    67  	v := T${1}
    68  	return v == [$]uint8{2} || v != [$]uint8{1}
    69  }`
    70
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