Re: [PATCH] analyzer: implement reference count checking for CPython plugin [PR107646]

[David Malcolm <dmalcolm@redhat.com>]

On Tue, 2023-08-29 at 00:31 -0400, Eric Feng wrote:
> Hi Dave,

Hi Eric.

Thanks for the updated patch.

A few nits below; this is OK for trunk with them fixed...

[...snip...]

> 
> gcc/analyzer/ChangeLog:
>   PR analyzer/107646
> 	* engine.cc (impl_region_model_context::warn): New optional parameter.
> 	* exploded-graph.h (class impl_region_model_context): Likewise.
> 	* region-model.cc (region_model::pop_frame): New callback feature for
>   * region_model::pop_frame.
> 	* region-model.h (struct append_regions_cb_data): Likewise.
> 	(class region_model): Likewise.
> 	(class region_model_context): New optional parameter.
> 	(class region_model_context_decorator): Likewise.
> 
> gcc/testsuite/ChangeLog:
>   PR analyzer/107646
> 	* gcc.dg/plugin/analyzer_cpython_plugin.c: Implements reference count
>   * checking for PyObjects.
> 	* gcc.dg/plugin/cpython-plugin-test-2.c: Moved to...
> 	* gcc.dg/plugin/cpython-plugin-test-PyList_Append.c: ...here (and
>   * added more tests).
> 	* gcc.dg/plugin/cpython-plugin-test-1.c: Moved to...
> 	* gcc.dg/plugin/cpython-plugin-test-no-plugin.c: ...here (and added
>   * more tests).
> 	* gcc.dg/plugin/plugin.exp: New tests.
> 	* gcc.dg/plugin/cpython-plugin-test-PyList_New.c: New test.
> 	* gcc.dg/plugin/cpython-plugin-test-PyLong_FromLong.c: New test.
> 	* gcc.dg/plugin/cpython-plugin-test-refcnt-checking.c: New test.

The ChangeLog formatting here seems wrong; lines starting with a '*'
should refer to a filename.  Continuation lines begin with just a tab
character.

[...snip...]

> diff --git a/gcc/analyzer/region-model.h b/gcc/analyzer/region-model.h
> index 10b2a59e787..440ea6d828d 100644
> --- a/gcc/analyzer/region-model.h
> +++ b/gcc/analyzer/region-model.h

[...snip...]

> @@ -840,7 +865,8 @@ private:
>  class region_model_context_decorator : public region_model_context
>  {
>   public:
> -  bool warn (std::unique_ptr<pending_diagnostic> d) override
> +  bool warn (std::unique_ptr<pending_diagnostic> d,
> +	     const stmt_finder *custom_finder)
>    {
>      if (m_inner)
>        return m_inner->warn (std::move (d));

This should presumably pass the custom_finder on to the 2nd argument of
m_inner->warn, rather than have the inner call to warn implicitly use
the NULL default arg.

[...snip...]

> diff --git a/gcc/testsuite/gcc.dg/plugin/cpython-plugin-test-1.c b/gcc/testsuite/gcc.dg/plugin/cpython-plugin-test-no-plugin.c
> similarity index 100%
> rename from gcc/testsuite/gcc.dg/plugin/cpython-plugin-test-1.c
> rename to gcc/testsuite/gcc.dg/plugin/cpython-plugin-test-no-plugin.c

Looks like
  "-no-Python-h.c"
would be a better suffix than
  "-no-plugin.c"
as it's the include that's missing, not the plugin.

[...snip...]

> diff --git a/gcc/testsuite/gcc.dg/plugin/plugin.exp b/gcc/testsuite/gcc.dg/plugin/plugin.exp
> index e1ed2d2589e..cbef6da8d86 100644
> --- a/gcc/testsuite/gcc.dg/plugin/plugin.exp
> +++ b/gcc/testsuite/gcc.dg/plugin/plugin.exp
> @@ -161,8 +161,9 @@ set plugin_test_list [list \
>  	  taint-CVE-2011-0521-6.c \
>  	  taint-antipatterns-1.c } \
>      { analyzer_cpython_plugin.c \
> -	  cpython-plugin-test-1.c \
> -	  cpython-plugin-test-2.c } \
> +	  cpython-plugin-test-PyList_Append.c \
> +	  cpython-plugin-test-PyList_New.c \
> +	  cpython-plugin-test-PyLong_FromLong.c } \

Looks like this is missing:
  cpython-plugin-test-no-plugin.c
and
  cpython-plugin-test-refcnt-checking.c
(though as noted above"cpython-plugin-test-no-Python-h.c" would be a
better name for the former)

so it wasn't actually compiling these tests.

Be sure to doublecheck that these tests pass when updating.

[...snip...]

OK for trunk with the above nits fixed.

Dave