Re: [PATCH v2 1/2] tracetool: add CHECK_TRACE_EVENT_GET_STATE

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Wed, Aug 06, 2025 at 03:05:38PM +0000, Tanish Desai wrote:
> New attributed added in backends
> CHECK_TRACE_EVENT_GET_STATE which when
> present and is True wraps the code generated
> by generate function in check_trace_event_get_state
> check else it is outside the conditional block.
> 
> Signed-off-by: Tanish Desai <tanishdesai37@gmail.com>
> ---
>  scripts/tracetool/__init__.py         |  1 -
>  scripts/tracetool/backend/__init__.py | 26 ++++++++++++++++-------
>  scripts/tracetool/format/h.py         | 30 ++++++++++-----------------
>  3 files changed, 30 insertions(+), 27 deletions(-)
> 
> diff --git a/scripts/tracetool/__init__.py b/scripts/tracetool/__init__.py
> index 2ae2e562d6..d0a02c45d7 100644
> --- a/scripts/tracetool/__init__.py
> +++ b/scripts/tracetool/__init__.py
> @@ -332,7 +332,6 @@ def formats(self):
>          return self._FMT.findall(self.fmt)
>  
>      QEMU_TRACE               = "trace_%(name)s"
> -    QEMU_TRACE_NOCHECK       = "_nocheck__" + QEMU_TRACE
>      QEMU_TRACE_TCG           = QEMU_TRACE + "_tcg"
>      QEMU_DSTATE              = "_TRACE_%(NAME)s_DSTATE"
>      QEMU_BACKEND_DSTATE      = "TRACE_%(NAME)s_BACKEND_DSTATE"
> diff --git a/scripts/tracetool/backend/__init__.py b/scripts/tracetool/backend/__init__.py
> index 7bfcc86cc5..4194719e52 100644
> --- a/scripts/tracetool/backend/__init__.py
> +++ b/scripts/tracetool/backend/__init__.py
> @@ -23,6 +23,8 @@
>  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', generate function
> +emits code inside check_trace_event_get_state check.
>  ========= ====================================================================

The '=' table formatting is broken. Further down in the file there is an
example of a wider first column and how the second column cells wrap:

=============================== ==============================================
Function                        Description
=============================== ==============================================
generate_<format>_begin(events) Generate backend- and format-specific file
                                header contents.

Please follow that style for consistency. You could also check reST
markup syntax alternatives like an unordered list if tables are too
clumsy.

>  
>  
> @@ -101,22 +103,32 @@ 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)

Spaces are missing on this line: 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)
> diff --git a/scripts/tracetool/format/h.py b/scripts/tracetool/format/h.py
> index ea126b07ea..0ceb49eef5 100644
> --- a/scripts/tracetool/format/h.py
> +++ b/scripts/tracetool/format/h.py
> @@ -59,33 +59,25 @@ def generate(events, backend, group):
>  
>          out('    false)')
>  
> -        # tracer without checks
>          out('',
>              'static inline void %(api)s(%(args)s)',
>              '{',
> -            api=e.api(e.QEMU_TRACE_NOCHECK),
> +            api=e.api(),
>              args=e.args)
>  
>          if "disable" not in e.properties:
> -            backend.generate(e, group)
> -
> +            backend.generate(e, group, check_trace_event_get_state=False)
> +
> +        if backend.check_trace_event_get_state:

This line can be indented...

> +            if "disable" not in e.properties:

...and this duplicate "disable" check can be dropped.

> +                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('}')
>  
> -        cond = "true"
> -
> -        out('',
> -            'static inline void %(api)s(%(args)s)',
> -            '{',
> -            '    if (%(cond)s) {',
> -            '        %(api_nocheck)s(%(names)s);',
> -            '    }',
> -            '}',
> -            api=e.api(),
> -            api_nocheck=e.api(e.QEMU_TRACE_NOCHECK),
> -            args=e.args,
> -            names=", ".join(e.args.names()),
> -            cond=cond)
> -
>      backend.generate_end(events, group)
>  
>      out('#endif /* TRACE_%s_GENERATED_TRACERS_H */' % group.upper())
> -- 
> 2.34.1
> 

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