* proc: move defer breakpoint code into a function
Moves the code that sets a breakpoint on the first deferred function,
used by both next and StepOut, to its function.
* proc: implement reverse step/next/stepout
When the direction of execution is reversed (on a recording) Step, Next and
StepOut will behave similarly to their forward version. However there are
some subtle interactions between their behavior, prologue skipping, deferred
calls and normal calls. Specifically:
- when stepping backwards we need to set a breakpoint on the first
instruction after each CALL instruction, once this breakpoint is reached we
need to execute a single StepInstruction operation to reverse step into the
CALL.
- to insure that the prologue is skipped reverse next needs to check if it
is on the first instruction after the prologue, and if it is behave like
reverse stepout.
- there is no reason to set breakpoints on deferred calls when reverse
nexting or reverse stepping out, they will never be hit.
- reverse step out should generally place its breakpoint on the CALL
instruction that created the current stack frame (which will be the CALL
instruction immediately preceding the instruction at the return address).
- reverse step out needs to treat panic calls and deferreturn calls
specially.
* service,terminal: implement reverse step, next, stepout
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