Getting rid of "Cannot access memory at address ..."

Shahab Vahedi shahab.vahedi@gmail.com
Wed Jan 8 13:48:00 GMT 2020


After talking with Andrew, it seems a possible solution could be using
try/catch to catch the usual suspect (a.k.a. MEMORY_ERROR):

Please let me know what you think of this change?

  diff --git a/gdb/tui/tui-disasm.c b/gdb/tui/tui-disasm.c
  index 98c691f3387..7faaa45f039 100644
  --- a/gdb/tui/tui-disasm.c
  +++ b/gdb/tui/tui-disasm.c
  @@ -226,7 +226,18 @@ tui_disasm_window::set_contents (struct gdbarch 
*arch,
     /* Get temporary table that will hold all strings (addr & insn).  */
     std::vector<tui_asm_line> asm_lines (max_lines);
     size_t addr_size = 0;
  -  tui_disassemble (gdbarch, asm_lines, pc, 0, max_lines, &addr_size);
  +  try
  +    {
  +      tui_disassemble (gdbarch, asm_lines, pc, 0, max_lines, &addr_size);
  +    }
  +  catch (const gdb_exception &except)
  +    {
  +      /* In cases where max_lines is asking tui_disassemble() to fetch
  +        too much, like when PC goes past the valid address range, a
  +        MEMORY_ERROR is thrown, but it is alright.  */
  +      if (except.error != MEMORY_ERROR)
  +         throw;
  +    }

     /* Align instructions to the same column.  */
     insn_pos = (1 + (addr_size / tab_len)) * tab_len;

My only concern is what if we have MEMORY_ERROR exception for reasons 
other than disassembling PC addresses that just went beyond the valid
range. Do such reasons exist in this scenario?

--
Shahab



More information about the Gdb mailing list