The disclosed embodiments provide a system that facilitates the execution of a software program. During operation, the system obtains a memory layout for an object instance in a software program, wherein the memory layout includes a set of offsets and a set of allocated sizes of a set of components associated with the object instance. Next, the system uses the memory layout to determine a first memory space occupied by data in the object instance and a second memory space occupied by padding in the object instance. The system then displays a visualization of the memory layout on the computer system, wherein the visualization includes a first graphical distinction between the first memory space and the second memory space.