[Qemu-devel] [RFC][PATCH v2 0/3] trace-instrument: let the user wrap/override code generated from trace-events

[Lluís <xscript@gmx.net>]

XXX: 'tracetool' could be simplified by never generating real tracing code for
     events with the "disable" property (not even with the 'simple' backend).
XXX: Must be applied on top of the 'backdoor' patch series

Adds a new optional keyword ("instrument") to the syntax in "trace-events". When
specified, this event property lets the user provide her own implementation for
that tracing event.

Still, in case the user only wants to wrap around the tracing event, tracetool's
original implementation is accessible through function 'trace_##name##_backend',
instead of the original 'trace_##name' (which now the user has to provide).

The user-provided tracing functions are expected to be in the static library
"libinstrument.a", identified by the "--with-instrument" configuration
parameter.

v2:

Rebase onto latest QEMU version (d33ea50a958b2e050d2b28e5f17e3b55e91c6d74).

Provide a '#define trace_##name##_enabled 1' in "trace.h" in case the tracing
point arguments need some extra computations only when enabled.


TODO:

 * Having the 'simple' backend generate code even when the "disable" property is
   present, complicates the flow in 'tracetool'.
   Is this behaviour really needed?

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---

Lluís Vilanova (3):
      trace: rewrite 'tracetool' to facilitate future extensions
      trace-instrument: let the user override events generated by 'tracetool'
      trace-instrument: handle config-time activation


 Makefile        |    4 -
 Makefile.target |   29 ++++-
 configure       |   30 +++++
 simpletrace.py  |    2 
 trace-events    |   23 +++-
 tracetool       |  340 +++++++++++++++++++++++++++++++++++--------------------
 6 files changed, 293 insertions(+), 135 deletions(-)