2017-05-14 16:45:26 +00:00
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=========================
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2016-05-23 22:09:38 +00:00
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GCC plugin infrastructure
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=========================
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2017-05-14 16:45:26 +00:00
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Introduction
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============
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2016-05-23 22:09:38 +00:00
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GCC plugins are loadable modules that provide extra features to the
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2017-05-14 16:45:26 +00:00
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compiler [1]_. They are useful for runtime instrumentation and static analysis.
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2016-05-23 22:09:38 +00:00
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We can analyse, change and add further code during compilation via
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2017-05-14 16:45:26 +00:00
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callbacks [2]_, GIMPLE [3]_, IPA [4]_ and RTL passes [5]_.
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2016-05-23 22:09:38 +00:00
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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The GCC plugin infrastructure of the kernel supports building out-of-tree
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modules, cross-compilation and building in a separate directory.
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Plugin source files have to be compilable by a C++ compiler.
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2016-05-23 22:09:38 +00:00
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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Currently the GCC plugin infrastructure supports only some architectures.
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Grep "select HAVE_GCC_PLUGINS" to find out which architectures support
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GCC plugins.
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2016-05-23 22:09:38 +00:00
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2017-05-14 16:45:26 +00:00
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This infrastructure was ported from grsecurity [6]_ and PaX [7]_.
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2016-05-23 22:09:38 +00:00
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--
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2017-05-14 16:45:26 +00:00
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.. [1] https://gcc.gnu.org/onlinedocs/gccint/Plugins.html
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.. [2] https://gcc.gnu.org/onlinedocs/gccint/Plugin-API.html#Plugin-API
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.. [3] https://gcc.gnu.org/onlinedocs/gccint/GIMPLE.html
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.. [4] https://gcc.gnu.org/onlinedocs/gccint/IPA.html
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.. [5] https://gcc.gnu.org/onlinedocs/gccint/RTL.html
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.. [6] https://grsecurity.net/
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.. [7] https://pax.grsecurity.net/
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2021-10-20 17:35:53 +00:00
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Purpose
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=======
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GCC plugins are designed to provide a place to experiment with potential
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compiler features that are neither in GCC nor Clang upstream. Once
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their utility is proven, the goal is to upstream the feature into GCC
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(and Clang), and then to finally remove them from the kernel once the
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feature is available in all supported versions of GCC.
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Specifically, new plugins should implement only features that have no
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upstream compiler support (in either GCC or Clang).
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When a feature exists in Clang but not GCC, effort should be made to
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bring the feature to upstream GCC (rather than just as a kernel-specific
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GCC plugin), so the entire ecosystem can benefit from it.
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Similarly, even if a feature provided by a GCC plugin does *not* exist
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in Clang, but the feature is proven to be useful, effort should be spent
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to upstream the feature to GCC (and Clang).
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After a feature is available in upstream GCC, the plugin will be made
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unbuildable for the corresponding GCC version (and later). Once all
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kernel-supported versions of GCC provide the feature, the plugin will
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be removed from the kernel.
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2017-05-14 16:45:26 +00:00
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Files
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=====
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2016-05-23 22:09:38 +00:00
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2017-05-14 16:45:26 +00:00
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**$(src)/scripts/gcc-plugins**
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2016-05-23 22:09:38 +00:00
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This is the directory of the GCC plugins.
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2017-05-14 16:45:26 +00:00
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**$(src)/scripts/gcc-plugins/gcc-common.h**
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2016-05-23 22:09:38 +00:00
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This is a compatibility header for GCC plugins.
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It should be always included instead of individual gcc headers.
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2017-05-14 16:45:26 +00:00
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**$(src)/scripts/gcc-plugins/gcc-generate-gimple-pass.h,
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$(src)/scripts/gcc-plugins/gcc-generate-ipa-pass.h,
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$(src)/scripts/gcc-plugins/gcc-generate-simple_ipa-pass.h,
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$(src)/scripts/gcc-plugins/gcc-generate-rtl-pass.h**
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2016-05-23 22:09:38 +00:00
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These headers automatically generate the registration structures for
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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GIMPLE, SIMPLE_IPA, IPA and RTL passes.
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2016-05-23 22:09:38 +00:00
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They should be preferred to creating the structures by hand.
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2017-05-14 16:45:26 +00:00
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Usage
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=====
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2016-05-23 22:09:38 +00:00
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You must install the gcc plugin headers for your gcc version,
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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e.g., on Ubuntu for gcc-10::
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2016-05-23 22:09:38 +00:00
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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apt-get install gcc-10-plugin-dev
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2016-05-23 22:09:38 +00:00
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2020-02-21 00:48:43 +00:00
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Or on Fedora::
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2022-08-27 19:38:36 +00:00
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dnf install gcc-plugin-devel libmpc-devel
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Or on Fedora when using cross-compilers that include plugins::
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dnf install libmpc-devel
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2020-02-21 00:48:43 +00:00
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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Enable the GCC plugin infrastructure and some plugin(s) you want to use
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in the kernel config::
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2016-05-23 22:09:38 +00:00
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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CONFIG_GCC_PLUGINS=y
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CONFIG_GCC_PLUGIN_LATENT_ENTROPY=y
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...
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2016-05-23 22:09:38 +00:00
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2022-08-27 19:38:36 +00:00
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Run gcc (native or cross-compiler) to ensure plugin headers are detected::
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gcc -print-file-name=plugin
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CROSS_COMPILE=arm-linux-gnu- ${CROSS_COMPILE}gcc -print-file-name=plugin
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The word "plugin" means they are not detected::
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plugin
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A full path means they are detected::
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/usr/lib/gcc/x86_64-redhat-linux/12/plugin
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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To compile the minimum tool set including the plugin(s)::
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2016-05-23 22:09:38 +00:00
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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make scripts
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2016-05-23 22:09:38 +00:00
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or just run the kernel make and compile the whole kernel with
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the cyclomatic complexity GCC plugin.
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4. How to add a new GCC plugin
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==============================
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doc: gcc-plugins: update gcc-plugins.rst
This document was written a long time ago. Update it.
[1] Drop the version information
The range of the supported GCC versions are always changing. The
current minimal GCC version is 4.9, and commit 1e860048c53e
("gcc-plugins: simplify GCC plugin-dev capability test") removed the
old code accordingly.
We do not need to mention specific version ranges like "all gcc versions
from 4.5 to 6.0" since we forget to update the documentation when we
raise the minimal compiler version.
[2] Drop the C compiler statements
Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7")
the GCC plugin infrastructure only supports g++.
[3] Drop supported architectures
As of v5.11-rc4, the infrastructure supports more architectures;
arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep
"select HAVE_GCC_PLUGINS") Again, we miss to update this document when a
new architecture is supported. Let's just say "only some architectures".
[4] Update the apt-get example
We are now discussing to bump the minimal version to GCC 5. The GCC 4.9
support will be removed sooner or later. Change the package example to
gcc-10-plugin-dev while we are here.
[5] Update the build target
Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/
via scripts/Makefile"), "make gcc-plugins" is not supported.
"make scripts" builds all the enabled plugins, including some other
tools.
[6] Update the steps for adding a new plugin
At first, all CONFIG options for GCC plugins were located in arch/Kconfig.
After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to
scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the
central place to collect plugin CONFIG options. In my understanding,
this requirement no longer exists because commit 9f671e58159a ("security:
Create "kernel hardening" config area") moved some of plugin CONFIG
options to another file. Find an appropriate place to add the new CONFIG.
The sub-directory support was never used by anyone, and removed by
commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR").
Remove the useless $(src)/ prefix.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-01-23 13:33:33 +00:00
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The GCC plugins are in scripts/gcc-plugins/. You need to put plugin source files
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right under scripts/gcc-plugins/. Creating subdirectories is not supported.
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It must be added to scripts/gcc-plugins/Makefile, scripts/Makefile.gcc-plugins
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and a relevant Kconfig file.
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