If you combine the lineinfo and the heaptrc information, then the output of the heaptrc unit will contain the names of the files and line numbers of the procedures that occur in the stack backtrace.
In such a case, the output will look something like this:
Marked memory at 00410DA0 invalid
Wrong size : 128 allocated 64 freed
0x0040D8F9 main, line 25 of heapex.pp
Call trace for block 0x00410DA0 size 128
0x0040D8ED main, line 23 of heapex.pp
If lines without filename / line number occur, this means there is a unit which has no debug info included (in the above case, the getmem call itself).