Bug ID: 23761
Summary: generalized @entry
Assignee: systemtap at sourceware dot org
Reporter: fche at redhat dot com
Target Milestone: ---
With the arrival of non-[uk]retprobe mechanisms to trap return events (e.g.,
tp_syscall.*.return), the traditional @entry(expression) trick is no longer
directly workable. This is because there is no mechanically-obvious entry
probe to collect the expression, and @entry($var) may need $var that are not
available at all in that form.
So we need to generalize this a bit.
One way is to introduce some macros that explicitly implement the @entry()
machinations behind the scenes:
- one macro to 'probe entry point & save variables'
- and one macro to 'probe exit point & expose saved variables'