Tracing Debugger

[jay-j]

You know your input value is good, but where did things go awry?

1. Tell the [debugger] you want to investigate between Point A (variable X at line 1234) and Point B (variable Y at line 5678).
2. [Debugger] finds data path between Point A and B, adds a logging trigger to each transformation.
3. Code execution, debugger collects values as they are calculated, and provides report.

Challenges: data that is only edited or accessed conditionally upon the value of other data (array indices, conditionals, etc.).

Bonus: cursor over a variable shows dependency graph of what affects that variable. Like Microsoft Excel's Trace Precedents tool.

A fake example:

#include <stdio.h>

void procedure1(int* value){
 *value += 3; 
}

int procedure2(int value){
  return value*2;
}

int main(){

  int value_start = 3;
  procedure1(&value_start);
  
  int value_mid = procedure2(value_start);
  value_start -= 2;
    
  int value_final = value_mid - value_start;
  value_mid += 10;
  value_final += 1;
  
  printf("The final value is %d\n", value_final);
  return 0;
}


/* 
Point A: line 13, value_start
Point B: line 23, value_final

Output:
(13) value_start = 3
( 4) value = 6
(14) value_start = 6
( 8) value = 12
(16) value_mid = 12
(17) value_start = 4
(19) value_final = 8
(21) value_final = 9
(22) value_final = 9
*/

[azmr]

This is under development as a tool in WhiteBox 😄
https://whitebox.systems