issue7690.go

     1  // run
     2  
     3  // Copyright 2014 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 7690 - Stack and other routines did not back up initial PC
     8  // into CALL instruction, instead reporting line number of next instruction,
     9  // which might be on a different line.
    10  
    11  package main
    12  
    13  import (
    14  	"bytes"
    15  	"regexp"
    16  	"runtime"
    17  	"strconv"
    18  )
    19  
    20  func main() {
    21  	buf1 := make([]byte, 1000)
    22  	buf2 := make([]byte, 1000)
    23  
    24  	runtime.Stack(buf1, false)      // CALL is last instruction on this line
    25  	n := runtime.Stack(buf2, false) // CALL is followed by load of result from stack
    26  
    27  	buf1 = buf1[:bytes.IndexByte(buf1, 0)]
    28  	buf2 = buf2[:n]
    29  
    30  	re := regexp.MustCompile(`(?m)^main\.main\(\)\n.*/issue7690.go:([0-9]+)`)
    31  	m1 := re.FindStringSubmatch(string(buf1))
    32  	if m1 == nil {
    33  		println("BUG: cannot find main.main in first trace")
    34  		return
    35  	}
    36  	m2 := re.FindStringSubmatch(string(buf2))
    37  	if m2 == nil {
    38  		println("BUG: cannot find main.main in second trace")
    39  		return
    40  	}
    41  
    42  	n1, _ := strconv.Atoi(m1[1])
    43  	n2, _ := strconv.Atoi(m2[1])
    44  	if n1+1 != n2 {
    45  		println("BUG: expect runtime.Stack on back to back lines, have", n1, n2)
    46  		println(string(buf1))
    47  		println(string(buf2))
    48  	}
    49  }
    50
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