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List:       llvm-dev
Subject:    [LLVMdev] operator overloading fails while debugging with gdb for i386
From:       Mayur Pandey <mayurthebond () gmail ! com>
Date:       2012-11-29 7:22:06
Message-ID: CAAk8+L7POBYWaBHS7OWJmX6mxr50864_YTZEFQn_2ian7F0B_g () mail ! gmail ! com
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For the given test:

class A1 {
  int x;
  int y;

  public:

  A1(int a, int b)
  {
   x=a;
   y=b;
  }

A1 operator+(const A1&);
};


A1 A1::operator+(const A1& second)
{
 A1 sum(0,0);
 sum.x = x + second.x;
 sum.y = y + second.y;

 return (sum);
}


int main (void)
{
 A1 one(2,3);
 A1 two(4,5);

 return 0;
}


when the exectable of this code is debugged in gdb for i386, we dont get the
expected results.

when we break at return 0; and give the command: print one + two, the result
should be $1 = {x = 6, y = 8}, but the result obtained is $1 = {x = 2, y = 3}.

This is related to debug information generated, as normally the overloading is
occuring.
eg: A1 three = one + two results {x = 6, y = 8}.


On checking the assembly, a suspicious entry is found which may be related for
the failure:

    #DEBUG_VALUE: operator+:this <- undef
    #DEBUG_VALUE: operator+:second <- undef



-- 
Thanx & Regards
*Mayur Pandey *

[Attachment #5 (text/html)]

<pre class="bz_comment_text" id="comment_text_0" \
style="font-size:small;font-family:monospace;white-space:pre-wrap;width:50em;color:rgb \
(0,0,0);font-style:normal;font-variant:normal;font-weight:normal;letter-spacing:normal \
;line-height:normal;text-align:start;text-indent:0px;text-transform:none;word-spacing:0px;background-color:rgb(255,255,255)">
 For the given test: 

class A1 {
  int x;
  int y;

  public:

  A1(int a, int b)
  {
   x=a;
   y=b;
  }

A1 operator+(const A1&amp;);
};


A1 A1::operator+(const A1&amp; second)
{
 A1 sum(0,0);
 sum.x = x + second.x;
 sum.y = y + second.y;

 return (sum);
}


int main (void)
{
 A1 one(2,3);
 A1 two(4,5);

 return 0;
}


when the exectable of this code is debugged in gdb for i386, we dont get the
expected results.

when we break at return 0; and give the command: print one + two, the result
should be $1 = {x = 6, y = 8}, but the result obtained is $1 = {x = 2, y = 3}.

This is related to debug information generated, as normally the overloading is
occuring.
eg: A1 three = one + two results {x = 6, y = 8}.


On checking the assembly, a suspicious entry is found which may be related for
the failure:

    #DEBUG_VALUE: operator+:this &lt;- undef
    #DEBUG_VALUE: operator+:second &lt;- undef</pre><br clear="all"><br>-- \
<br><div>Thanx &amp; Regards <br></div> <div><b>Mayur Pandey \
</b><br></div><br><div><font color="#3333ff"> <br></font></div> <div> </div>
<div> </div><br>



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