Large memory usage by gdb

My OS is Ubuntu 17.04. Using both gdb 7.12 and 8.0, I experience large 
memory usage when debugging my executable. As I add breakpoints and run 
the executable multiple times in a single session, memory usage grows 
continuously, regularly hitting 10s of GBs. I don't recall experiencing 
this issue with earlier Ubuntu versions (and also likely earlier 
versions of gdb). When I debug the same executable with `lldb`, memory 
usage is pretty much constant at around 2 GB. Does anyone have any 
suggestions?

Alex