This is useful for language runtimes that compute register values by inspecting the state of the currently running process. Currently, there are no mechanisms enabling these runtimes to set register values to arbitrary values. The alternative considered would involve creating a dwarf expression that produces an arbitrary integer (e.g. using OP_constu). However, the current data structure for Rows is such that they do not own any memory associated with dwarf expressions, which implies any such expression would need to have static storage and therefore could not contain a runtime value. Adding a new rule for constants leads to a simpler implementation. It's also worth noting that this does not make the "Location" union any bigger, since it already contains a pointer+size pair.
19 KiB
19 KiB