Hi,
GCC plugins should only exist when some compiler feature needs to be
proven but does not exist in either GCC nor Clang. For example, if a
desired feature is already in Clang, it should be added to GCC upstream.
Document this explicitly.
I'll put this in -next unless there are objections. :)
Thanks!
-Kees
Kees Cook (2):
gcc-plugins: Explicitly document purpose and deprecation schedule
gcc-plugins: Remove cyc_complexity
Documentation/kbuild/gcc-plugins.rst | 28 ++++++++-
scripts/Makefile.gcc-plugins | 2 -
scripts/gcc-plugins/Kconfig | 20 +-----
scripts/gcc-plugins/cyc_complexity_plugin.c | 69 ---------------------
security/Kconfig.hardening | 9 ++-
5 files changed, 34 insertions(+), 94 deletions(-)
delete mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c
--
2.30.2
This plugin has no impact on the resulting binary, is disabled
under COMPILE_TEST, and is not enabled on any builds I'm aware of.
Additionally, given the clarified purpose of GCC plugins in the kernel,
remove cyc_complexity.
Cc: Masahiro Yamada <[email protected]>
Cc: Michal Marek <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Kees Cook <[email protected]>
---
Documentation/kbuild/gcc-plugins.rst | 2 -
scripts/Makefile.gcc-plugins | 2 -
scripts/gcc-plugins/Kconfig | 16 -----
scripts/gcc-plugins/cyc_complexity_plugin.c | 69 ---------------------
4 files changed, 89 deletions(-)
delete mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c
diff --git a/Documentation/kbuild/gcc-plugins.rst b/Documentation/kbuild/gcc-plugins.rst
index 4b28c7a4032f..0ba76719f1b9 100644
--- a/Documentation/kbuild/gcc-plugins.rst
+++ b/Documentation/kbuild/gcc-plugins.rst
@@ -96,7 +96,6 @@ Enable the GCC plugin infrastructure and some plugin(s) you want to use
in the kernel config::
CONFIG_GCC_PLUGINS=y
- CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=y
CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
...
@@ -115,4 +114,3 @@ The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files
right under scripts/gcc-plugins/. Creating subdirectories is not supported.
It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins
and a relevant Kconfig file.
-See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin.
diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
index 952e46876329..6583ecf2e674 100644
--- a/scripts/Makefile.gcc-plugins
+++ b/scripts/Makefile.gcc-plugins
@@ -1,7 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
-gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) += cyc_complexity_plugin.so
-
gcc-plugin-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) += latent_entropy_plugin.so
gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) \
+= -DLATENT_ENTROPY_PLUGIN
diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
index 3f5d3580ec06..821a725a7f5c 100644
--- a/scripts/gcc-plugins/Kconfig
+++ b/scripts/gcc-plugins/Kconfig
@@ -19,22 +19,6 @@ menuconfig GCC_PLUGINS
if GCC_PLUGINS
-config GCC_PLUGIN_CYC_COMPLEXITY
- bool "Compute the cyclomatic complexity of a function" if EXPERT
- depends on !COMPILE_TEST # too noisy
- help
- The complexity M of a function's control flow graph is defined as:
- M = E - N + 2P
- where
-
- E = the number of edges
- N = the number of nodes
- P = the number of connected components (exit nodes).
-
- Enabling this plugin reports the complexity to stderr during the
- build. It mainly serves as a simple example of how to create a
- gcc plugin for the kernel.
-
config GCC_PLUGIN_SANCOV
bool
# Plugin can be removed once the kernel only supports GCC 6.1.0+
diff --git a/scripts/gcc-plugins/cyc_complexity_plugin.c b/scripts/gcc-plugins/cyc_complexity_plugin.c
deleted file mode 100644
index 73124c2b3edd..000000000000
--- a/scripts/gcc-plugins/cyc_complexity_plugin.c
+++ /dev/null
@@ -1,69 +0,0 @@
-/*
- * Copyright 2011-2016 by Emese Revfy <[email protected]>
- * Licensed under the GPL v2, or (at your option) v3
- *
- * Homepage:
- * https://github.com/ephox-gcc-plugins/cyclomatic_complexity
- *
- * https://en.wikipedia.org/wiki/Cyclomatic_complexity
- * The complexity M is then defined as:
- * M = E - N + 2P
- * where
- *
- * E = the number of edges of the graph
- * N = the number of nodes of the graph
- * P = the number of connected components (exit nodes).
- *
- * Usage (4.5 - 5):
- * $ make clean; make run
- */
-
-#include "gcc-common.h"
-
-__visible int plugin_is_GPL_compatible;
-
-static struct plugin_info cyc_complexity_plugin_info = {
- .version = "20160225",
- .help = "Cyclomatic Complexity\n",
-};
-
-static unsigned int cyc_complexity_execute(void)
-{
- int complexity;
- expanded_location xloc;
-
- /* M = E - N + 2P */
- complexity = n_edges_for_fn(cfun) - n_basic_blocks_for_fn(cfun) + 2;
-
- xloc = expand_location(DECL_SOURCE_LOCATION(current_function_decl));
- fprintf(stderr, "Cyclomatic Complexity %d %s:%s\n", complexity,
- xloc.file, DECL_NAME_POINTER(current_function_decl));
-
- return 0;
-}
-
-#define PASS_NAME cyc_complexity
-
-#define NO_GATE
-#define TODO_FLAGS_FINISH TODO_dump_func
-
-#include "gcc-generate-gimple-pass.h"
-
-__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
-{
- const char * const plugin_name = plugin_info->base_name;
-
- PASS_INFO(cyc_complexity, "ssa", 1, PASS_POS_INSERT_AFTER);
-
- if (!plugin_default_version_check(version, &gcc_version)) {
- error(G_("incompatible gcc/plugin versions"));
- return 1;
- }
-
- register_callback(plugin_name, PLUGIN_INFO, NULL,
- &cyc_complexity_plugin_info);
- register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL,
- &cyc_complexity_pass_info);
-
- return 0;
-}
--
2.30.2
On Wed, Oct 20, 2021 at 7:35 PM Kees Cook <[email protected]> wrote:
>
> - * Copyright 2011-2016 by Emese Revfy <[email protected]>
Perhaps we should Cc this address to give them notice.
Reviewed-by: Miguel Ojeda <[email protected]>
Cheers,
Miguel
On Wed, Oct 20, 2021 at 10:35:54AM -0700, Kees Cook wrote:
> This plugin has no impact on the resulting binary, is disabled
> under COMPILE_TEST, and is not enabled on any builds I'm aware of.
> Additionally, given the clarified purpose of GCC plugins in the kernel,
> remove cyc_complexity.
>
> Cc: Masahiro Yamada <[email protected]>
> Cc: Michal Marek <[email protected]>
> Cc: Nick Desaulniers <[email protected]>
> Cc: Jonathan Corbet <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Kees Cook <[email protected]>
Reviewed-by: Nathan Chancellor <[email protected]>
One comment below.
> ---
> Documentation/kbuild/gcc-plugins.rst | 2 -
> scripts/Makefile.gcc-plugins | 2 -
> scripts/gcc-plugins/Kconfig | 16 -----
> scripts/gcc-plugins/cyc_complexity_plugin.c | 69 ---------------------
> 4 files changed, 89 deletions(-)
> delete mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c
>
> diff --git a/Documentation/kbuild/gcc-plugins.rst b/Documentation/kbuild/gcc-plugins.rst
> index 4b28c7a4032f..0ba76719f1b9 100644
> --- a/Documentation/kbuild/gcc-plugins.rst
> +++ b/Documentation/kbuild/gcc-plugins.rst
> @@ -96,7 +96,6 @@ Enable the GCC plugin infrastructure and some plugin(s) you want to use
> in the kernel config::
>
> CONFIG_GCC_PLUGINS=y
> - CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=y
> CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
> ...
>
There is a comment about the cyc_complexity plugin at the very end of
this file that should also be removed it seems:
"See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin."
> @@ -115,4 +114,3 @@ The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files
> right under scripts/gcc-plugins/. Creating subdirectories is not supported.
> It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins
> and a relevant Kconfig file.
> -See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin.
> diff --git a/scripts/Makefile.gcc-plugins b/scripts/Makefile.gcc-plugins
> index 952e46876329..6583ecf2e674 100644
> --- a/scripts/Makefile.gcc-plugins
> +++ b/scripts/Makefile.gcc-plugins
> @@ -1,7 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0
>
> -gcc-plugin-$(CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) += cyc_complexity_plugin.so
> -
> gcc-plugin-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) += latent_entropy_plugin.so
> gcc-plugin-cflags-$(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) \
> += -DLATENT_ENTROPY_PLUGIN
> diff --git a/scripts/gcc-plugins/Kconfig b/scripts/gcc-plugins/Kconfig
> index 3f5d3580ec06..821a725a7f5c 100644
> --- a/scripts/gcc-plugins/Kconfig
> +++ b/scripts/gcc-plugins/Kconfig
> @@ -19,22 +19,6 @@ menuconfig GCC_PLUGINS
>
> if GCC_PLUGINS
>
> -config GCC_PLUGIN_CYC_COMPLEXITY
> - bool "Compute the cyclomatic complexity of a function" if EXPERT
> - depends on !COMPILE_TEST # too noisy
> - help
> - The complexity M of a function's control flow graph is defined as:
> - M = E - N + 2P
> - where
> -
> - E = the number of edges
> - N = the number of nodes
> - P = the number of connected components (exit nodes).
> -
> - Enabling this plugin reports the complexity to stderr during the
> - build. It mainly serves as a simple example of how to create a
> - gcc plugin for the kernel.
> -
> config GCC_PLUGIN_SANCOV
> bool
> # Plugin can be removed once the kernel only supports GCC 6.1.0+
> diff --git a/scripts/gcc-plugins/cyc_complexity_plugin.c b/scripts/gcc-plugins/cyc_complexity_plugin.c
> deleted file mode 100644
> index 73124c2b3edd..000000000000
> --- a/scripts/gcc-plugins/cyc_complexity_plugin.c
> +++ /dev/null
> @@ -1,69 +0,0 @@
> -/*
> - * Copyright 2011-2016 by Emese Revfy <[email protected]>
> - * Licensed under the GPL v2, or (at your option) v3
> - *
> - * Homepage:
> - * https://github.com/ephox-gcc-plugins/cyclomatic_complexity
> - *
> - * https://en.wikipedia.org/wiki/Cyclomatic_complexity
> - * The complexity M is then defined as:
> - * M = E - N + 2P
> - * where
> - *
> - * E = the number of edges of the graph
> - * N = the number of nodes of the graph
> - * P = the number of connected components (exit nodes).
> - *
> - * Usage (4.5 - 5):
> - * $ make clean; make run
> - */
> -
> -#include "gcc-common.h"
> -
> -__visible int plugin_is_GPL_compatible;
> -
> -static struct plugin_info cyc_complexity_plugin_info = {
> - .version = "20160225",
> - .help = "Cyclomatic Complexity\n",
> -};
> -
> -static unsigned int cyc_complexity_execute(void)
> -{
> - int complexity;
> - expanded_location xloc;
> -
> - /* M = E - N + 2P */
> - complexity = n_edges_for_fn(cfun) - n_basic_blocks_for_fn(cfun) + 2;
> -
> - xloc = expand_location(DECL_SOURCE_LOCATION(current_function_decl));
> - fprintf(stderr, "Cyclomatic Complexity %d %s:%s\n", complexity,
> - xloc.file, DECL_NAME_POINTER(current_function_decl));
> -
> - return 0;
> -}
> -
> -#define PASS_NAME cyc_complexity
> -
> -#define NO_GATE
> -#define TODO_FLAGS_FINISH TODO_dump_func
> -
> -#include "gcc-generate-gimple-pass.h"
> -
> -__visible int plugin_init(struct plugin_name_args *plugin_info, struct plugin_gcc_version *version)
> -{
> - const char * const plugin_name = plugin_info->base_name;
> -
> - PASS_INFO(cyc_complexity, "ssa", 1, PASS_POS_INSERT_AFTER);
> -
> - if (!plugin_default_version_check(version, &gcc_version)) {
> - error(G_("incompatible gcc/plugin versions"));
> - return 1;
> - }
> -
> - register_callback(plugin_name, PLUGIN_INFO, NULL,
> - &cyc_complexity_plugin_info);
> - register_callback(plugin_name, PLUGIN_PASS_MANAGER_SETUP, NULL,
> - &cyc_complexity_pass_info);
> -
> - return 0;
> -}
> --
> 2.30.2
>
On Wed, Oct 20, 2021 at 10:35 AM Kees Cook <[email protected]> wrote:
>
> Hi,
>
> GCC plugins should only exist when some compiler feature needs to be
> proven but does not exist in either GCC nor Clang. For example, if a
> desired feature is already in Clang, it should be added to GCC upstream.
> Document this explicitly.
>
> I'll put this in -next unless there are objections. :)
Acked-by: Nick Desaulniers <[email protected]>
>
> Thanks!
>
> -Kees
>
>
> Kees Cook (2):
> gcc-plugins: Explicitly document purpose and deprecation schedule
> gcc-plugins: Remove cyc_complexity
>
> Documentation/kbuild/gcc-plugins.rst | 28 ++++++++-
> scripts/Makefile.gcc-plugins | 2 -
> scripts/gcc-plugins/Kconfig | 20 +-----
> scripts/gcc-plugins/cyc_complexity_plugin.c | 69 ---------------------
> security/Kconfig.hardening | 9 ++-
> 5 files changed, 34 insertions(+), 94 deletions(-)
> delete mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c
>
> --
> 2.30.2
>
--
Thanks,
~Nick Desaulniers
On Wed, Oct 20, 2021 at 10:48:59AM -0700, Nathan Chancellor wrote:
> On Wed, Oct 20, 2021 at 10:35:54AM -0700, Kees Cook wrote:
> > This plugin has no impact on the resulting binary, is disabled
> > under COMPILE_TEST, and is not enabled on any builds I'm aware of.
> > Additionally, given the clarified purpose of GCC plugins in the kernel,
> > remove cyc_complexity.
> >
> > Cc: Masahiro Yamada <[email protected]>
> > Cc: Michal Marek <[email protected]>
> > Cc: Nick Desaulniers <[email protected]>
> > Cc: Jonathan Corbet <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Kees Cook <[email protected]>
>
> Reviewed-by: Nathan Chancellor <[email protected]>
>
> One comment below.
>
> > ---
> > Documentation/kbuild/gcc-plugins.rst | 2 -
> > scripts/Makefile.gcc-plugins | 2 -
> > scripts/gcc-plugins/Kconfig | 16 -----
> > scripts/gcc-plugins/cyc_complexity_plugin.c | 69 ---------------------
> > 4 files changed, 89 deletions(-)
> > delete mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c
> >
> > diff --git a/Documentation/kbuild/gcc-plugins.rst b/Documentation/kbuild/gcc-plugins.rst
> > index 4b28c7a4032f..0ba76719f1b9 100644
> > --- a/Documentation/kbuild/gcc-plugins.rst
> > +++ b/Documentation/kbuild/gcc-plugins.rst
> > @@ -96,7 +96,6 @@ Enable the GCC plugin infrastructure and some plugin(s) you want to use
> > in the kernel config::
> >
> > CONFIG_GCC_PLUGINS=y
> > - CONFIG_GCC_PLUGIN_CYC_COMPLEXITY=y
> > CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
> > ...
> >
>
> There is a comment about the cyc_complexity plugin at the very end of
> this file that should also be removed it seems:
>
> "See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin."
Yup; I think it was hiding from you, see here:
>
> > @@ -115,4 +114,3 @@ The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files
> > right under scripts/gcc-plugins/. Creating subdirectories is not supported.
> > It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins
> > and a relevant Kconfig file.
> > -See the cyc_complexity_plugin.c (CONFIG_GCC_PLUGIN_CYC_COMPLEXITY) GCC plugin.
^^^^
:)
Thanks!
-Kees
--
Kees Cook
On Wed, Oct 20, 2021 at 07:48:55PM +0200, Miguel Ojeda wrote:
> On Wed, Oct 20, 2021 at 7:35 PM Kees Cook <[email protected]> wrote:
> >
> > - * Copyright 2011-2016 by Emese Revfy <[email protected]>
>
> Perhaps we should Cc this address to give them notice.
Good point; I'm in the habit of that happening automatically as Emese
was a co-maintainer of the gcc-plugins. Sorry for the oversight here.
> Reviewed-by: Miguel Ojeda <[email protected]>
Thanks!
--
Kees Cook
On Wed, 20 Oct 2021 at 19:35, Kees Cook <[email protected]> wrote:
>
> Hi,
>
> GCC plugins should only exist when some compiler feature needs to be
> proven but does not exist in either GCC nor Clang. For example, if a
> desired feature is already in Clang, it should be added to GCC upstream.
> Document this explicitly.
>
> I'll put this in -next unless there are objections. :)
>
> Thanks!
>
> -Kees
>
>
> Kees Cook (2):
> gcc-plugins: Explicitly document purpose and deprecation schedule
> gcc-plugins: Remove cyc_complexity
>
Acked-by: Ard Biesheuvel <[email protected]>
> Documentation/kbuild/gcc-plugins.rst | 28 ++++++++-
> scripts/Makefile.gcc-plugins | 2 -
> scripts/gcc-plugins/Kconfig | 20 +-----
> scripts/gcc-plugins/cyc_complexity_plugin.c | 69 ---------------------
> security/Kconfig.hardening | 9 ++-
> 5 files changed, 34 insertions(+), 94 deletions(-)
> delete mode 100644 scripts/gcc-plugins/cyc_complexity_plugin.c
>
> --
> 2.30.2
>