[Qemu-devel] [PATCH v4 00/10] trace: [tcg] Allow tracing guest events in TCG-generated code

[Lluís Vilanova]

NOTE: TCG code for execution-time event tracing is always generated, regardless
      of wether the event has been dynamically disabled or not (unless the event
      has the static "disable" property).

      This approach keeps this series simple, and a future series will handle
      the case of having per-CPU tracing states for these events, and only
      generate the code if the event is dynamicaly enabled.

Adds the base ability to specify which events in the "trace-events" file may be
used to trace guest activity in the TCG code (using the "tcg" event propery).

An event with that property actually generates two independent events
"${name}_trans" and "${name}_exec", and a set of conveniency functions. Having
two events allows us to trace both translation and execution of guest code
(e.g., generating vs executing a basic block). See the first patch for more
information on its usage.

Files generating guest code (TCG) must include "trace-tcg.h".

The flow of the generated routines is (convenience wrappers are inlined):


[At translation time]

* trace_${name}_tcg(bool, TCGv)
  Declared: "trace/generated-tcg-tracers.h"
  Defined : "trace/generated-tcg-tracers.h"

  Invokes "trace_${name}_trans" (with all non-TCG arguments) and
  "gen_helper_trace_${name}_exec" (with all arguments).

* trace_${name}_trans(bool)
  Declared: "trace/generated-tracers.h"
  Defined : "trace/generated-tracers.h"

  Invokes the actual tracing backends for the translation-time event.

* gen_helper_trace_${name}_exec(bool, TCGv)
  Declared: "trace/generated-helpers.h"
  Defined : "trace/generated-helpers.h"

  Convenience wrapper that will allocate (and free) TCG temporaries for all
  non-TCG arguments before calling "gen_helper_trace_${name}_exec_proxy".

* gen_helper_trace_${name}_exec_proxy(TCGi32, TCGv)
  Declared: "trace/generated-helpers.h"
  Defined : "trace/generated-helpers.h" (using helper machinery)

  The actual TCG helper function, created using QEMU's TCG helper machinery.


[At execution time]

* helper_trace_${name}_exec_proxy(uint32_t, uint64_t)
  Declared: "trace/generated-helpers.h"
  Defined : "trace/generated-helpers.c"

  Convenience wrapper that casts arguments to the appropriate type before
  calling "trace_${name}_exec".

  This is necessary because TCG helpers can only receive a limited number of
  argument types (e.g., must use 'uint32_t' instead of 'bool').

* trace_${name}_exec(bool, uint64_t)
  Declared: "trace/generated-tracers.h"
  Defined : "trace/generated-tracers.h"

  Invokes the actual tracing backends for the execution-time event.

Signed-off-by: Lluís Vilanova <address@hidden>
---

Changes in v4:

* Rebase on d7d3d60 (use new helper header machinery).

Changes in v3:

* None (re-send with cover).

Changes in v2:

* Split the guest memory access event out of this series.
* Generate two independent events from each "tcg" event (one for
  translation-time events and one for execution-time events).


Lluís Vilanova (10):
      trace: [tcg] Add documentation
      trace: [tcg] Argument type transformation rules
      trace: [tcg] Argument type transformation machinery
      trace: [tcg] Add 'tcg' event property
      trace: [tcg] Declare TCG tracing helper routines
      trace: [tcg] Define TCG tracing helper routines
      trace: [tcg] Include TCG-tracing helpers
      trace: [tcg] Generate TCG tracing routines
      trace: [tcg] Include event definitions in "trace.h"
      trace: [tcg] Include TCG-tracing header on all targets


 .gitignore                               |    3 +
 Makefile                                 |    5 +
 Makefile.objs                            |    7 +
 Makefile.target                          |    5 +
 docs/tracing.txt                         |   40 +++++++
 include/exec/helper-gen.h                |    3 +
 include/exec/helper-proto.h              |    1 
 include/exec/helper-tcg.h                |    1 
 include/trace-tcg.h                      |    7 +
 include/trace.h                          |    1 
 scripts/tracetool/__init__.py            |   95 ++++++++++++++++-
 scripts/tracetool/format/events_h.py     |    5 +
 scripts/tracetool/format/tcg_h.py        |   57 ++++++++++
 scripts/tracetool/format/tcg_helper_c.py |   50 +++++++++
 scripts/tracetool/format/tcg_helper_h.py |   90 ++++++++++++++++
 scripts/tracetool/transform.py           |  166 ++++++++++++++++++++++++++++++
 target-alpha/translate.c                 |    3 +
 target-arm/translate-a64.c               |    2 
 target-arm/translate.c                   |    3 +
 target-cris/translate.c                  |    3 +
 target-i386/translate.c                  |    3 +
 target-lm32/translate.c                  |    3 +
 target-m68k/translate.c                  |    3 +
 target-microblaze/translate.c            |    3 +
 target-mips/translate.c                  |    3 +
 target-openrisc/translate.c              |    3 +
 target-ppc/translate.c                   |    3 +
 target-s390x/translate.c                 |    2 
 target-sh4/translate.c                   |    3 +
 target-sparc/translate.c                 |    3 +
 target-unicore32/translate.c             |    3 +
 target-xtensa/translate.c                |    3 +
 trace/Makefile.objs                      |   45 +++++++-
 33 files changed, 615 insertions(+), 12 deletions(-)
 create mode 100644 include/trace-tcg.h
 create mode 100644 scripts/tracetool/format/tcg_h.py
 create mode 100644 scripts/tracetool/format/tcg_helper_c.py
 create mode 100644 scripts/tracetool/format/tcg_helper_h.py
 create mode 100644 scripts/tracetool/transform.py


To: address@hidden
Cc: Stefan Hajnoczi <address@hidden>
Cc: Richard Henderson <address@hidden>
Cc: Peter Maydell <address@hidden>