4.2 Debugging VHDL programs

Debugging VHDL programs using GDB is possible only on GNU/Linux systems.

GDB is a general purpose debugger for programs compiled by GCC. Currently, there is no VHDL support for GDB. It may be difficult to inspect variables or signals in GDB, however, GDB is still able to display the stack frame in case of error or to set a breakpoint at a specified line.

GDB can be useful to precisely catch a runtime error, such as indexing an array beyond its bounds. All error check subprograms call the __ghdl_fatal procedure. Therefore, to catch runtime error, set a breakpoint like this:

     (gdb) break __ghdl_fatal

When the breakpoint is hit, use the where or bt command to display the stack frames.