On Mon, Jul 20, 2015 at 11:36:46AM -0500, Josh Poimboeuf wrote: > If a function doesn't call any other functions, then it won't ever show > up in a stack trace unless: > > a) the function itself walks the stack, in which case the frame pointer > isn't necessary; or > > b) The function gets hit by an interrupt/exception, in which case frame > pointers can't be 100% relied upon anyway. In case the interrupt happens whilst setting up the frame, right? > I've noticed that gcc *does* seem to create stack frames for leaf > functions. But it's inconsistent, because the early exit path of some > functions will skip the stack frame creation and go straight to the > return. > > We could probably get a good performance boost with the > -momit-leaf-frame-pointer flag. Though it would make stack traces less > reliable when a leaf function gets interrupted. So the information we'd loose in that case would be the location in the calling function, right? Which isn't a problem, if the current function (as obtained through RIP) is only ever called once. However if there's multiple call sites this might be a wee bit confusing. -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
