Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

Tracing pull request

* remotes/stefanha/tags/tracing-pull-request:
  virtio-rng: add some trace events
  trace: add some tcg tracing support
  trace: teach lttng backend to use format strings
  trace: [tcg] Include TCG-tracing header on all targets
  trace: [tcg] Include event definitions in "trace.h"
  trace: [tcg] Generate TCG tracing routines
  trace: [tcg] Include TCG-tracing helpers
  trace: [tcg] Define TCG tracing helper routine wrappers
  trace: [tcg] Define TCG tracing helper routines
  trace: [tcg] Declare TCG tracing helper routines
  trace: [tcg] Add 'tcg' event property
  trace: [tcg] Argument type transformation machinery
  trace: [tcg] Argument type transformation rules
  trace: [tcg] Add documentation
  trace: install simpletrace SystemTap tapset
  simpletrace: add simpletrace.py --no-header option
  trace: add tracetool simpletrace_stap format
  trace: extract stap_escape() function for reuse

Conflicts:
	Makefile.objs

1 files changed, 40 insertions, 0 deletions

diff --git a/docs/tracing.txt b/docs/tracing.txt
index c6ab1c11c1..2e035a5b3c 100644
--- a/docs/tracing.txt
+++ b/docs/tracing.txt
@@ -307,3 +307,43 @@ guard such computations and avoid its compilation when the event is disabled:
 You can check both if the event has been disabled and is dynamically enabled at
 the same time using the 'trace_event_get_state' routine (see header
 "trace/control.h" for more information).
+
+=== "tcg" ===
+
+Guest code generated by TCG can be traced by defining an event with the "tcg"
+event property. Internally, this property generates two events:
+"<eventname>_trans" to trace the event at translation time, and
+"<eventname>_exec" to trace the event at execution time.
+
+Instead of using these two events, you should instead use the function
+"trace_<eventname>_tcg" during translation (TCG code generation). This function
+will automatically call "trace_<eventname>_trans", and will generate the
+necessary TCG code to call "trace_<eventname>_exec" during guest code execution.
+
+Events with the "tcg" property can be declared in the "trace-events" file with a
+mix of native and TCG types, and "trace_<eventname>_tcg" will gracefully forward
+them to the "<eventname>_trans" and "<eventname>_exec" events. Since TCG values
+are not known at translation time, these are ignored by the "<eventname>_trans"
+event. Because of this, the entry in the "trace-events" file needs two printing
+formats (separated by a comma):
+
+    tcg foo(uint8_t a1, TCGv_i32 a2) "a1=%d", "a1=%d a2=%d"
+
+For example:
+
+    #include "trace-tcg.h"
+    
+    void some_disassembly_func (...)
+    {
+        uint8_t a1 = ...;
+        TCGv_i32 a2 = ...;
+        trace_foo_tcg(a1, a2);
+    }
+
+This will immediately call:
+
+    void trace_foo_trans(uint8_t a1);
+
+and will generate the TCG code to call:
+
+    void trace_foo(uint8_t a1, uint32_t a2);