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[Arushi Aggarwal <arushi987 AT gmail.com>]

On Fri, Feb 18, 2011 at 10:10 PM, Tarek Chammah <tchammah AT uwaterloo.ca> wrote:

Hi, this issue is possibly a blocker for me.  I'm utilizing DSA to
garner points-to information.  After the top down pass is run and the
buildDSNodeEquivs method is executed to place DSNodes between callers
and callees into their equivalence classes I get rather strange
output.  Using a simple test I dump the nodes in the resulting
equivalence classes.  What I get is a pair of distinct nodes in the
ECs that contain the same program variable/value location information.
 I don't understand why this information is repeated.

I believe the nodes are distinct nodes from different graphs, which map to the

same points-to set. The reason they appear multiple times is because they are

distinct nodes.

 

Eg. I get this, two ECs each containing a pair with repeated
information (about G2 and the string constant):
Node0x1008870 [shape=record,shape=Mrecord,label="{i32: GR\n@G2 + 1
EC\n|{<s0>|<s1>|<s2>|<s3>}}"];
Node0xff4950 [shape=record,shape=Mrecord,label="{i32: GR\n@G2 + 1
EC\n|{<s0>|<s1>|<s2>|<s3>}}"];

Node0x1008af0 [shape=record,shape=Mrecord,label="{i8 array:
GR\n@.str\n|{<s0>}}"];
Node0xff4d50 [shape=record,shape=Mrecord,label="{i8 array:
GR\n@.str\n|{<s0>}}"];

For this sample program:
#include <stdio.h>

int G1 = 4, G2 = 3;
int *XX, *YY;

int main() {
      XX = &G1;
      YY = XX;
      YY = &G2;
      XX = &G2;
      if (*XX>*YY) printf("Not possible!\n");
      return 0;
}


Thanks,

Tarek
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