[PATCH v3 23/24] trace: remove parsing of "disable" event property

["Daniel P. Berrangé" <berrange@redhat.com>]

Finish the removal of the "disable" event property by removing code
that parses properties and the backend code generators.

This "fixes" a bug in the UST backends which looked for a property
called "disabled" instead of "disable".

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 docs/devel/tracing.rst                       | 24 +++-------------
 scripts/tracetool/__init__.py                | 27 ++++--------------
 scripts/tracetool/backend/dtrace.py          |  2 --
 scripts/tracetool/format/c.py                |  9 ++----
 scripts/tracetool/format/d.py                |  3 --
 scripts/tracetool/format/h.py                | 30 +++++++++-----------
 scripts/tracetool/format/log_stap.py         |  3 --
 scripts/tracetool/format/rs.py               | 26 ++++++++---------
 scripts/tracetool/format/simpletrace_stap.py |  3 --
 scripts/tracetool/format/stap.py             |  3 --
 scripts/tracetool/format/ust_events_c.py     |  3 --
 scripts/tracetool/format/ust_events_h.py     |  3 --
 12 files changed, 39 insertions(+), 97 deletions(-)

diff --git a/docs/devel/tracing.rst b/docs/devel/tracing.rst
index f4557ee20e4..f94063587fa 100644
--- a/docs/devel/tracing.rst
+++ b/docs/devel/tracing.rst
@@ -366,30 +366,14 @@ To facilitate simple usage of systemtap where there merely needs to be printf
 logging of certain probes, a helper script "qemu-trace-stap" is provided.
 Consult its manual page for guidance on its usage.
 
-Trace event properties
+Trace event conditions
 ======================
 
-Each event in the "trace-events-all" file can be prefixed with a space-separated
-list of zero or more of the following event properties.
-
-"disable"
----------
-
-If a specific trace event is going to be invoked a huge number of times, this
-might have a noticeable performance impact even when the event is
-programmatically disabled.
-
-In this case you should declare such event with the "disable" property. This
-will effectively disable the event at compile time (by using the "nop" backend),
-thus having no performance impact at all on regular builds (i.e., unless you
-edit the "trace-events-all" file).
-
-In addition, there might be cases where relatively complex computations must be
+There might be cases where relatively complex computations must be
 performed to generate values that are only used as arguments for a trace
 function. In these cases you can use 'trace_event_get_state_backends()' to
-guard such computations, so they are skipped if the event has been either
-compile-time disabled or run-time disabled. If the event is compile-time
-disabled, this check will have no performance impact.
+guard such computations, so they are skipped if the event is not currently
+enabled:
 
 ::
 
diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
index 6ed7cdd6ce4..bdbb06b5205 100644
--- a/scripts/tracetool/__init__.py
+++ b/scripts/tracetool/__init__.py
@@ -362,8 +362,6 @@ class Event(object):
         The event name.
     fmt : str
         The event format string.
-    properties : set(str)
-        Properties of the event.
     args : Arguments
         The event arguments.
     lineno : int
@@ -373,23 +371,18 @@ class Event(object):
 
     """
 
-    _CRE = re.compile(r"((?P<props>[\w\s]+)\s+)?"
-                      r"(?P<name>\w+)"
+    _CRE = re.compile(r"(?P<name>\w+)"
                       r"\((?P<args>[^)]*)\)"
                       r"\s*"
                       r"(?P<fmt>\".+)?"
                       r"\s*")
 
-    _VALID_PROPS = set(["disable"])
-
-    def __init__(self, name, props, fmt, args, lineno, filename):
+    def __init__(self, name, fmt, args, lineno, filename):
         """
         Parameters
         ----------
         name : string
             Event name.
-        props : list of str
-            Property names.
         fmt : str
             Event printing format string.
         args : Arguments
@@ -401,7 +394,6 @@ def __init__(self, name, props, fmt, args, lineno, filename):
 
         """
         self.name = name
-        self.properties = props
         self.fmt = fmt
         self.args = args
         self.lineno = int(lineno)
@@ -411,11 +403,6 @@ def __init__(self, name, props, fmt, args, lineno, filename):
             raise ValueError("Event '%s' has more than maximum permitted "
                              "argument count" % name)
 
-        unknown_props = set(self.properties) - self._VALID_PROPS
-        if len(unknown_props) > 0:
-            raise ValueError("Unknown properties: %s"
-                             % ", ".join(unknown_props))
-
 
     @staticmethod
     def build(line_str, lineno, filename):
@@ -435,7 +422,6 @@ def build(line_str, lineno, filename):
         groups = m.groupdict('')
 
         name = groups["name"]
-        props = groups["props"].split()
         fmt = groups["fmt"]
         if fmt.find("%m") != -1:
             raise ValueError("Event format '%m' is forbidden, pass the error "
@@ -448,14 +434,13 @@ def build(line_str, lineno, filename):
 
         args = Arguments.build(groups["args"])
 
-        return Event(name, props, fmt, args, lineno, posix_relpath(filename))
+        return Event(name, fmt, args, lineno, posix_relpath(filename))
 
     def __repr__(self):
         """Evaluable string representation for this object."""
-        return "Event('%s %s(%s) %s')" % (" ".join(self.properties),
-                                          self.name,
-                                          self.args,
-                                          self.fmt)
+        return "Event('%s(%s) %s')" % (self.name,
+                                       self.args,
+                                       self.fmt)
     # Star matching on PRI is dangerous as one might have multiple
     # arguments with that format, hence the non-greedy version of it.
     _FMT = re.compile(r"(%[\d\.]*\w+|%.*?PRI\S+)")
diff --git a/scripts/tracetool/backend/dtrace.py b/scripts/tracetool/backend/dtrace.py
index f0b58cc1585..6bce25c8d2d 100644
--- a/scripts/tracetool/backend/dtrace.py
+++ b/scripts/tracetool/backend/dtrace.py
@@ -79,8 +79,6 @@ def generate_rs_begin(events, group):
     # These are the Rust declarations of the .probes section semaphores
     # generated by dtrace(1) in its .o file output.
     for e in events:
-        if 'disable' in e.properties:
-            continue
         out('    #[allow(dead_code)]',
             f'    static qemu_{e.name}_semaphore: UnsafeCell<u16>;')
     out('}',
diff --git a/scripts/tracetool/format/c.py b/scripts/tracetool/format/c.py
index 9f06894623e..3754c7e06fd 100644
--- a/scripts/tracetool/format/c.py
+++ b/scripts/tracetool/format/c.py
@@ -16,9 +16,6 @@
 
 
 def generate(events, backend, group):
-    active_events = [e for e in events
-                     if "disable" not in e.properties]
-
     header = "trace-" + group + ".h"
 
     out('/* This file is autogenerated by tracetool, do not edit. */',
@@ -62,7 +59,7 @@ def generate(events, backend, group):
             'trace_init(trace_%(group)s_register_events)',
             group = group.lower())
 
-        backend.generate_begin(active_events, group)
-        for event in active_events:
+        backend.generate_begin(events, group)
+        for event in events:
             backend.generate(event, group)
-        backend.generate_end(active_events, group)
+        backend.generate_end(events, group)
diff --git a/scripts/tracetool/format/d.py b/scripts/tracetool/format/d.py
index e9e33dfe30a..df7780cb0af 100644
--- a/scripts/tracetool/format/d.py
+++ b/scripts/tracetool/format/d.py
@@ -30,9 +30,6 @@
 
 
 def generate(events, backend, group):
-    events = [e for e in events
-              if "disable" not in e.properties]
-
     # SystemTap's dtrace(1) warns about empty "provider qemu {}" but is happy
     # with an empty file.  Avoid the warning.
     # But dtrace on macOS can't deal with empty files.
diff --git a/scripts/tracetool/format/h.py b/scripts/tracetool/format/h.py
index 544bbc0ba93..f719fe09397 100644
--- a/scripts/tracetool/format/h.py
+++ b/scripts/tracetool/format/h.py
@@ -46,14 +46,13 @@ def generate(events, backend, group):
             '#define %(api)s() ( \\',
             api=e.api(e.QEMU_BACKEND_DSTATE))
 
-        if "disable" not in e.properties:
-            backend.generate_backend_dstate(e, group, check_trace_event_get_state=False)
+        backend.generate_backend_dstate(e, group, check_trace_event_get_state=False)
 
-            if backend.check_trace_event_get_state:
-                event_id = 'TRACE_' + e.name.upper()
-                out('    trace_event_get_state_dynamic_by_id(%(event_id)s) || \\',
-                    event_id=event_id)
-                backend.generate_backend_dstate(e, group, check_trace_event_get_state=True)
+        if backend.check_trace_event_get_state:
+            event_id = 'TRACE_' + e.name.upper()
+            out('    trace_event_get_state_dynamic_by_id(%(event_id)s) || \\',
+                event_id=event_id)
+            backend.generate_backend_dstate(e, group, check_trace_event_get_state=True)
 
         out('    false)')
 
@@ -63,16 +62,15 @@ def generate(events, backend, group):
             api=e.api(),
             args=e.args)
 
-        if "disable" not in e.properties:
-            backend.generate(e, group, check_trace_event_get_state=False)
+        backend.generate(e, group, check_trace_event_get_state=False)
 
-            if backend.check_trace_event_get_state:
-                event_id = 'TRACE_' + e.name.upper()
-                cond = "trace_event_get_state(%s)" % event_id
-                out('    if (%(cond)s) {',
-                        cond=cond)
-                backend.generate(e, group, check_trace_event_get_state=True)
-                out('    }')
+        if backend.check_trace_event_get_state:
+            event_id = 'TRACE_' + e.name.upper()
+            cond = "trace_event_get_state(%s)" % event_id
+            out('    if (%(cond)s) {',
+                cond=cond)
+            backend.generate(e, group, check_trace_event_get_state=True)
+            out('    }')
         out('}')
 
     backend.generate_end(events, group)
diff --git a/scripts/tracetool/format/log_stap.py b/scripts/tracetool/format/log_stap.py
index 259303a189d..3fa6c2dd3f2 100644
--- a/scripts/tracetool/format/log_stap.py
+++ b/scripts/tracetool/format/log_stap.py
@@ -90,9 +90,6 @@ def generate(events, backend, group):
         '')
 
     for event_id, e in enumerate(events):
-        if 'disable' in e.properties:
-            continue
-
         out('probe %(probeprefix)s.log.%(name)s = %(probeprefix)s.%(name)s ?',
             '{',
             probeprefix=probeprefix(),
diff --git a/scripts/tracetool/format/rs.py b/scripts/tracetool/format/rs.py
index 1fddcee1ad2..97d89a981da 100644
--- a/scripts/tracetool/format/rs.py
+++ b/scripts/tracetool/format/rs.py
@@ -52,11 +52,10 @@ def generate(events, backend, group):
             '{',
             api=e.api(e.QEMU_RUST_DSTATE))
 
-        if "disable" not in e.properties:
-            backend.generate_backend_dstate(e, group)
-            if backend.check_trace_event_get_state:
-                out('    trace_event_state_is_enabled(unsafe { _%(event_id)s_DSTATE}) ||',
-                    event_id = 'TRACE_' + e.name.upper())
+        backend.generate_backend_dstate(e, group)
+        if backend.check_trace_event_get_state:
+            out('    trace_event_state_is_enabled(unsafe { _%(event_id)s_DSTATE}) ||',
+                event_id = 'TRACE_' + e.name.upper())
 
         out('    false',
             '}',
@@ -68,15 +67,14 @@ def generate(events, backend, group):
             api=e.api(e.QEMU_TRACE),
             args=e.args.rust_decl())
 
-        if "disable" not in e.properties:
-            backend.generate(e, group, check_trace_event_get_state=False)
-            if backend.check_trace_event_get_state:
-                event_id = 'TRACE_' + e.name.upper()
-                out('    if trace_event_state_is_enabled(unsafe { _%(event_id)s_DSTATE}) {',
-                    event_id = event_id,
-                    api=e.api())
-                backend.generate(e, group, check_trace_event_get_state=True)
-                out('    }')
+        backend.generate(e, group, check_trace_event_get_state=False)
+        if backend.check_trace_event_get_state:
+            event_id = 'TRACE_' + e.name.upper()
+            out('    if trace_event_state_is_enabled(unsafe { _%(event_id)s_DSTATE}) {',
+                event_id = event_id,
+                api=e.api())
+            backend.generate(e, group, check_trace_event_get_state=True)
+            out('    }')
         out('}',
             '')
 
diff --git a/scripts/tracetool/format/simpletrace_stap.py b/scripts/tracetool/format/simpletrace_stap.py
index c7bde97a855..393d85319c7 100644
--- a/scripts/tracetool/format/simpletrace_stap.py
+++ b/scripts/tracetool/format/simpletrace_stap.py
@@ -24,9 +24,6 @@ def generate(events, backend, group):
         '')
 
     for event_id, e in enumerate(events):
-        if 'disable' in e.properties:
-            continue
-
         out('probe %(probeprefix)s.simpletrace.%(name)s = %(probeprefix)s.%(name)s ?',
             '{',
             probeprefix=probeprefix(),
diff --git a/scripts/tracetool/format/stap.py b/scripts/tracetool/format/stap.py
index 285c9203ba7..e3d16b72d34 100644
--- a/scripts/tracetool/format/stap.py
+++ b/scripts/tracetool/format/stap.py
@@ -34,9 +34,6 @@ def stap_escape(identifier):
 
 
 def generate(events, backend, group):
-    events = [e for e in events
-              if "disable" not in e.properties]
-
     out('/* This file is autogenerated by tracetool, do not edit. */',
         '/* SPDX-License-Identifier: GPL-2.0-or-later */',
         '')
diff --git a/scripts/tracetool/format/ust_events_c.py b/scripts/tracetool/format/ust_events_c.py
index 074226bfd37..93f88a03e90 100644
--- a/scripts/tracetool/format/ust_events_c.py
+++ b/scripts/tracetool/format/ust_events_c.py
@@ -16,9 +16,6 @@
 
 
 def generate(events, backend, group):
-    events = [e for e in events
-              if "disabled" not in e.properties]
-
     out('/* This file is autogenerated by tracetool, do not edit. */',
         '/* SPDX-License-Identifier: GPL-2.0-or-later */',
         '',
diff --git a/scripts/tracetool/format/ust_events_h.py b/scripts/tracetool/format/ust_events_h.py
index 76c883bc5c0..441e6a41933 100644
--- a/scripts/tracetool/format/ust_events_h.py
+++ b/scripts/tracetool/format/ust_events_h.py
@@ -16,9 +16,6 @@
 
 
 def generate(events, backend, group):
-    events = [e for e in events
-              if "disabled" not in e.properties]
-
     if group == "all":
         include = "trace-ust-all.h"
     else:
-- 
2.55.0