[Qemu-devel] [PATCH] trace: teach lttng backend to use format strings

[alex.bennee@linaro.org]

From: Alex Bennée <alex.bennee@linaro.org>

This makes the UST backend pay attention to the format string arguments
that are defined when defining payload data. With this you can now
ensure integers are reported in hex mode if you want.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
---
 scripts/tracetool/__init__.py    | 13 +++++++++++--
 scripts/tracetool/backend/ust.py | 16 ++++++++++++----
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
index 175df08..abcdc49 100644
--- a/scripts/tracetool/__init__.py
+++ b/scripts/tracetool/__init__.py
@@ -118,13 +118,16 @@ class Event(object):
         Properties of the event.
     args : Arguments
         The event arguments.
+    arg_fmts : str
+        The format strings for each arugment.
     """
 
     _CRE = re.compile("((?P<props>.*)\s+)?(?P<name>[^(\s]+)\((?P<args>[^)]*)\)\s*(?P<fmt>\".*)?")
+    _FMT = re.compile("(%\w+|%.*PRI\S+)")
 
     _VALID_PROPS = set(["disable"])
 
-    def __init__(self, name, props, fmt, args):
+    def __init__(self, name, props, fmt, args, arg_fmts):
         """
         Parameters
         ----------
@@ -136,11 +139,15 @@ class Event(object):
             Event printing format.
         args : Arguments
             Event arguments.
+        arg_fmts : list of str
+            Format strings for each argument
+
         """
         self.name = name
         self.properties = props
         self.fmt = fmt
         self.args = args
+        self.arg_fmts = arg_fmts
 
         unknown_props = set(self.properties) - self._VALID_PROPS
         if len(unknown_props) > 0:
@@ -163,8 +170,10 @@ class Event(object):
         props = groups["props"].split()
         fmt = groups["fmt"]
         args = Arguments.build(groups["args"])
+        print "%s: %s and %s" % (name, args, fmt)
+        arg_fmts = Event._FMT.findall(fmt)
 
-        return Event(name, props, fmt, args)
+        return Event(name, props, fmt, args, arg_fmts)
 
     def __repr__(self):
         """Evaluable string representation for this object."""
diff --git a/scripts/tracetool/backend/ust.py b/scripts/tracetool/backend/ust.py
index 41c1c75..cb09958 100644
--- a/scripts/tracetool/backend/ust.py
+++ b/scripts/tracetool/backend/ust.py
@@ -56,13 +56,21 @@ def ust_events_h(events):
                 args = ", ".join(", ".join(i) for i in e.args),
                 )
 
-            for t,n in e.args:
-                if ('int' in t) or ('long' in t) or ('unsigned' in t) or ('size_t' in t):
+            types = e.args.types()
+            names = e.args.names()
+            fmts = e.arg_fmts
+            print "/* %s/%s/%s */" % (types, names, fmts)
+            for t,n,f in zip(types, names, fmts):
+                if ('char *' in t) or ('char*' in t):
+                    out('       ctf_string(' + n + ', ' + n + ')')
+                elif ("%p" in f) or ("x" in f) or ("PRIx" in f):
+                    out('       ctf_integer_hex('+ t + ', ' + n + ', ' + n + ')')
+                elif ("ptr" in t) or ("*" in t):
+                    out('       ctf_integer_hex('+ t + ', ' + n + ', ' + n + ')')
+                elif ('int' in t) or ('long' in t) or ('unsigned' in t) or ('size_t' in t):
                     out('       ctf_integer(' + t + ', ' + n + ', ' + n + ')')
                 elif ('double' in t) or ('float' in t):
                     out('       ctf_float(' + t + ', ' + n + ', ' + n + ')')
-                elif ('char *' in t) or ('char*' in t):
-                    out('       ctf_string(' + n + ', ' + n + ')')
                 elif ('void *' in t) or ('void*' in t):
                     out('       ctf_integer_hex(unsigned long, ' + n + ', ' + n + ')')
 
-- 
1.9.1