memcheck/tests/origin4-many.c

   1
   2 /* This test case was originally written by Nicholas Nethercote. */
   3
   4
   5
   6
   7 /* For 'x', we get an uninitialised error for every addition to it.  For
   8    each one we get one origin identified, even though most of them involve
   9    more than one undefined value. */
  10
  11 /* For 'y', we get a single uninitialised value error, on the value handed
  12    to the exit() system call.  Fair enough.
  13
  14    An important question is: which of the origins is reported in the
  15    error?  Well, considering that (1) m_execontext allocates ECUs
  16    (origin tags, basically) in increasing order, and (2) memcheck's
  17    instrumentation for dealing with two uninitialised sources simply
  18    involves 'max'-ing the otags, we expect the origin to be attributed
  19    to the last of the 8 mallocs, that is, to p_ui8.
  20 */
  21
  22 #include <stdlib.h>
  23 #include <stdio.h>
  24
  25 static int x = 0;
  26 static int y = 0;
  27
  28 int main(void)
  29 {
  30    // Do them separately rather than all in one array so they all have
  31    // different origins.
  32    int* p_ui1 = malloc(sizeof(int));
  33    int* p_ui2 = malloc(sizeof(int));
  34    int* p_ui3 = malloc(sizeof(int));
  35    int* p_ui4 = malloc(sizeof(int));
  36    int* p_ui5 = malloc(sizeof(int));
  37    int* p_ui6 = malloc(sizeof(int));
  38    int* p_ui7 = malloc(sizeof(int));
  39    int* p_ui8 = malloc(sizeof(int));
  40    int  ui1 = *p_ui1;
  41    int  ui2 = *p_ui2;
  42    int  ui3 = *p_ui3;
  43    int  ui4 = *p_ui4;
  44    int  ui5 = *p_ui5;
  45    int  ui6 = *p_ui6;
  46    int  ui7 = *p_ui7;
  47    int  ui8 = *p_ui8;
  48
  49 #define P   printf("huh?")
  50
  51    x += (ui1                                    == 0x12345678 ? P : 23);
  52    x += (ui1 +ui2                               == 0x12345678 ? P : 24);
  53    x += (ui1 +ui2 +ui3                          == 0x12345678 ? P : 25);
  54    x += (ui1 +ui2 +ui3 +ui4                     == 0x12345678 ? P : 26);
  55    x += (ui1 +ui2 +ui3 +ui4 +ui5                == 0x12345678 ? P : 27);
  56    x += (ui1 +ui2 +ui3 +ui4 +ui5 +ui6           == 0x12345678 ? P : 28);
  57    x += (ui1 +ui2 +ui3 +ui4 +ui5 +ui6 +ui7      == 0x12345678 ? P : 29);
  58    x += (ui1 +ui2 +ui3 +ui4 +ui5 +ui6 +ui7 +ui8 == 0x12345678 ? P : 30);
  59
  60    y += (ui1                                   );
  61    y += (ui1 +ui2                              );
  62    y += (ui1 +ui2 +ui3                         );
  63    y += (ui1 +ui2 +ui3 +ui4                    );
  64    y += (ui1 +ui2 +ui3 +ui4 +ui5               );
  65    y += (ui1 +ui2 +ui3 +ui4 +ui5 +ui6          );
  66    y += (ui1 +ui2 +ui3 +ui4 +ui5 +ui6 +ui7     );
  67    y += (ui1 +ui2 +ui3 +ui4 +ui5 +ui6 +ui7 +ui8);
  68
  69    return y & 1;
  70 }