gdb: safety checks in skip_prologue_using_sal
While working on the previous patch I reverted this commit:
commit e86e87f77fd5d8afb3e714f1d9e09e0ff5b4e6ff
Date: Tue Nov 28 16:23:32 2006 +0000
* symtab.c (find_pc_sect_line): Do not return a line before
the start of a symtab.
When I re-ran the testsuite I saw some GDB crashes in the tests:
gdb.dwarf2/dw2-line-number-zero.exp
gdb.dwarf2/dw2-lines.exp
gdb.dwarf2/dw2-vendor-extended-opcode.exp
GDB was reading beyond the end of an array in the function
skip_prologue_using_sal.
Now, without the above commit reverted I don't believe that this
should ever happen. Reverting the above commit effectively breaks
GDB's symtab_and_line lookup, we try to find a result for an address,
and return the wrong symtab and line-table. In
skip_prologue_using_sal we then walk the line table looking for an
appropriate entry, except we never find one, and GDB just keeps going,
wandering off the end of the array.
However, I think adding extra protection to prevent walking off the
end of the array is pretty cheap, and if something does go wrong in
the future then this should prevent a random crash.
Obviously, I have no reproducer for this, as I said, I don't think
this should impact GDB at all, this is just adding a little extra
caution.
Reviewed-By: Tom Tromey <tom@tromey.com>
1 file changed
