A method is provided for synthesizing an HLL program. For one or more variables to observe and/or control in a function of the HLL program, a first code segment is added to the function in the HLL program. For each of the one or more variables a respective second code segment is also added to the HLL program. In response to encountering the first code segment during synthesis of the HLL program, a memory is instantiated in a synthesized design. In response to encountering the second code segment during synthesis of the HLL program, a respective interface circuit is instantiated in the synthesized design. Each interface circuit is configured to replicate a state of the corresponding variable in the memory during operation of the synthesized design. A table is generated that maps names of the one or more variables to respective memory addresses in the memory.