Merge tag 'tracing-pull-request' of https://gitlab.com/stefanha/qemu into staging

Pull request

Tanish Desai and Paolo Bonzini's tracing Rust support.

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* tag 'tracing-pull-request' of https://gitlab.com/stefanha/qemu:
  tracetool/syslog: add Rust support
  tracetool/ftrace: add Rust support
  tracetool/log: add Rust support
  log: change qemu_loglevel to unsigned
  tracetool/simple: add Rust support
  rust: pl011: add tracepoints
  rust: qdev: add minimal clock bindings
  rust: add trace crate
  tracetool: Add Rust format support
  tracetool/backend: remove redundant trace event checks
  tracetool: add CHECK_TRACE_EVENT_GET_STATE
  trace/ftrace: move snprintf+write from tracepoints to ftrace.c
  tracetool: add SPDX headers
  treewide: remove unnessary "coding" header
  tracetool: remove dead code
  tracetool: fix usage of try_import()

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 29 insertions, 14 deletions

diff --git a/scripts/tracetool/backend/__init__.py b/scripts/tracetool/backend/__init__.py
index 7bfcc86cc5..9109a783c7 100644
--- a/scripts/tracetool/backend/__init__.py
+++ b/scripts/tracetool/backend/__init__.py
@@ -1,4 +1,4 @@
-# -*- coding: utf-8 -*-
+# SPDX-License-Identifier: GPL-2.0-or-later
 
 """
 Backend management.
@@ -19,11 +19,15 @@ All backends must generate their contents through the 'tracetool.out' routine.
 Backend attributes
 ------------------
 
-========= ====================================================================
-Attribute Description
-========= ====================================================================
-PUBLIC    If exists and is set to 'True', the backend is considered "public".
-========= ====================================================================
+=========================== ====================================================
+Attribute                   Description
+=========================== ====================================================
+PUBLIC                      If exists and is set to 'True', the backend is
+                            considered "public".
+CHECK_TRACE_EVENT_GET_STATE If exists and is set to 'True', the backend-specific
+                            code inside the tracepoint is emitted within an
+                            ``if trace_event_get_state()`` conditional.
+=========================== ====================================================
 
 
 Backend functions
@@ -94,29 +98,40 @@ def exists(name):
     if name == "nop":
         return True
     name = name.replace("-", "_")
-    return tracetool.try_import("tracetool.backend." + name)[1]
+    return tracetool.try_import("tracetool.backend." + name)[0]
 
 
 class Wrapper:
     def __init__(self, backends, format):
         self._backends = [backend.replace("-", "_") for backend in backends]
         self._format = format.replace("-", "_")
+        self.check_trace_event_get_state = False
         for backend in self._backends:
             assert exists(backend)
         assert tracetool.format.exists(self._format)
+        for backend in self.backend_modules():
+            check_trace_event_get_state = getattr(backend, "CHECK_TRACE_EVENT_GET_STATE", False)
+            self.check_trace_event_get_state = self.check_trace_event_get_state or check_trace_event_get_state
 
-    def _run_function(self, name, *args, **kwargs):
+    def backend_modules(self):
         for backend in self._backends:
-            func = tracetool.try_import("tracetool.backend." + backend,
-                                        name % self._format, None)[1]
-            if func is not None:
-                func(*args, **kwargs)
+             module = tracetool.try_import("tracetool.backend." + backend)[1]
+             if module is not None:
+                 yield module
+
+    def _run_function(self, name, *args, check_trace_event_get_state=None, **kwargs):
+        for backend in self.backend_modules():
+            func = getattr(backend, name % self._format, None)
+            if func is not None and \
+                (check_trace_event_get_state is None or
+                 check_trace_event_get_state == getattr(backend, 'CHECK_TRACE_EVENT_GET_STATE', False)):
+                    func(*args, **kwargs)
 
     def generate_begin(self, events, group):
         self._run_function("generate_%s_begin", events, group)
 
-    def generate(self, event, group):
-        self._run_function("generate_%s", event, group)
+    def generate(self, event, group, check_trace_event_get_state=None):
+        self._run_function("generate_%s", event, group, check_trace_event_get_state=check_trace_event_get_state)
 
     def generate_backend_dstate(self, event, group):
         self._run_function("generate_%s_backend_dstate", event, group)