[Qemu-devel] [PATCH v4 1/2] trace: teach lttng backend to use format strings

["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>

---

v2
  - remove silly debug statements
v3
  - fix spelling
  - rebase to latest tracetool
v4:
  - rebase onto tracing-next

diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
index a51e0f2..36c789d 100644
--- a/scripts/tracetool/__init__.py
+++ b/scripts/tracetool/__init__.py
@@ -136,6 +136,8 @@ class Event(object):
         Properties of the event.
     args : Arguments
         The event arguments.
+    arg_fmts : str
+        The format strings for each argument.
     """
 
     _CRE = re.compile("((?P<props>.*)\s+)?"
@@ -144,10 +146,11 @@ class Event(object):
                       "\s*"
                       "(?:(?:(?P<fmt_trans>\".+),)?\s*(?P<fmt>\".+))?"
                       "\s*")
+    _FMT = re.compile("(%\w+|%.*PRI\S+)")
 
     _VALID_PROPS = set(["disable", "tcg", "tcg-trans", "tcg-exec"])
 
-    def __init__(self, name, props, fmt, args, orig=None):
+    def __init__(self, name, props, fmt, args, arg_fmts, orig=None):
         """
         Parameters
         ----------
@@ -159,13 +162,17 @@ class Event(object):
             Event printing format (or formats).
         args : Arguments
             Event arguments.
+        arg_fmts : list of str
+            Format strings for each argument.
         orig : Event or None
             Original Event before transformation.
+
         """
         self.name = name
         self.properties = props
         self.fmt = fmt
         self.args = args
+        self.arg_fmts = arg_fmts
 
         if orig is None:
             self.original = weakref.ref(self)
@@ -203,6 +210,7 @@ class Event(object):
         if len(fmt_trans) > 0:
             fmt = [fmt_trans, fmt]
         args = Arguments.build(groups["args"])
+        arg_fmts = Event._FMT.findall(fmt)
 
         if "tcg-trans" in props:
             raise ValueError("Invalid property 'tcg-trans'")
@@ -213,7 +221,7 @@ class Event(object):
         if "tcg" in props and isinstance(fmt, str):
             raise ValueError("Events with 'tcg' property must have two formats")
 
-        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/format/ust_events_h.py b/scripts/tracetool/format/ust_events_h.py
index 5102565..d189899 100644
--- a/scripts/tracetool/format/ust_events_h.py
+++ b/scripts/tracetool/format/ust_events_h.py
@@ -63,13 +63,20 @@ def generate(events, backend):
                 name=e.name,
                 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
+            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 + ')')
 
-- 
2.0.3