[PATCH] bug in build_parse (parse.c)

[David Taylor <taylor at cygnus dot com>]

In build_parse, you'll find the lines:

      num_std_regs = 0;
    #ifdef PC_REGNUM
      if (PC_REGNUM >= 0)
	num_std_regs++;
    #endif
    #ifdef FP_REGNUM
      if (FP_REGNUM >= 0)
	num_std_regs++;
    #endif
    #ifdef SP_REGNUM
      if (SP_REGNUM >= 0)
	num_std_regs++;
    #endif
    #ifdef PS_REGNUM
      if (PS_REGNUM >= 0)
	num_std_regs++;
    #endif

Notice how num_std_regs only gets incremented if {PC_REGNUM,
FP_REGNUM, SP_REGNUM, PS_REGNUM} is *BOTH* defined and >= 0.

      /* create an empty table */
      std_regs = xmalloc ((num_std_regs + 1) * sizeof *std_regs);

But notice how it gets filled in if it's defined, regardless of
whether it is >= 0 or not:

      i = 0;
      /* fill it in */
    #ifdef PC_REGNUM
      std_regs[i].name = "pc";
      std_regs[i].regnum = PC_REGNUM;
      i++;
    #endif
    #ifdef FP_REGNUM
      std_regs[i].name = "fp";
      std_regs[i].regnum = FP_REGNUM;
      i++;
    #endif
    #ifdef SP_REGNUM
      std_regs[i].name = "sp";
      std_regs[i].regnum = SP_REGNUM;
      i++;
    #endif
    #ifdef PS_REGNUM
      std_regs[i].name = "ps";
      std_regs[i].regnum = PS_REGNUM;
      i++;
    #endif

Thus, if one of more of them is defined (possibly because other parts
of GDB won't compile if it's not defined), but is defined as -1
(because the processor doesn't support it of there is no ABI or...),
then build_parse will write off the end of the std_regs array.

Ooops.  Here's a patch to fix it:

Index: parse.c
===================================================================
RCS file: /cvs/src/src/gdb/parse.c,v
retrieving revision 1.8
diff -c -r1.8 parse.c
*** parse.c     2000/07/30 01:48:26     1.8
--- parse.c     2000/08/07 14:20:31
***************
*** 1331,1354 ****
    i = 0;
    /* fill it in */
  #ifdef PC_REGNUM
!   std_regs[i].name = "pc";
!   std_regs[i].regnum = PC_REGNUM;
!   i++;
  #endif
  #ifdef FP_REGNUM
!   std_regs[i].name = "fp";
!   std_regs[i].regnum = FP_REGNUM;
!   i++;
  #endif
  #ifdef SP_REGNUM
!   std_regs[i].name = "sp";
!   std_regs[i].regnum = SP_REGNUM;
!   i++;
  #endif
  #ifdef PS_REGNUM
!   std_regs[i].name = "ps";
!   std_regs[i].regnum = PS_REGNUM;
!   i++;
  #endif
    memset (&std_regs[i], 0, sizeof (std_regs[i]));
  }
--- 1331,1366 ----
    i = 0;
    /* fill it in */
  #ifdef PC_REGNUM
!   if (PC_REGNUM >= 0)
!     {
!       std_regs[i].name = "pc";
!       std_regs[i].regnum = PC_REGNUM;
!       i++;
!     }
  #endif
  #ifdef FP_REGNUM
!   if (FP_REGNUM >= 0)
!     {
!       std_regs[i].name = "fp";
!       std_regs[i].regnum = FP_REGNUM;
!       i++;
!     }
  #endif
  #ifdef SP_REGNUM
!   if (SP_REGNUM >= 0)
!     {
!       std_regs[i].name = "sp";
!       std_regs[i].regnum = SP_REGNUM;
!       i++;
!     }
  #endif
  #ifdef PS_REGNUM
!   if (PS_REGNUM >= 0)
!     {
!       std_regs[i].name = "ps";
!       std_regs[i].regnum = PS_REGNUM;
!       i++;
!     }
  #endif
    memset (&std_regs[i], 0, sizeof (std_regs[i]));
  }