Isn't that an argument against many optimizations, such as function inlining? In any case, it's possible to have both, if the compiler outputs some (optional)

Isn't that an argument against many optimizations, such as function inlining? In any case, it's possible to have both, if the compiler outputs some (optional) extra debug information. For example, gcc has options that let you reconstruct a 'virtual' stack trace in gdb even for inlined functions.