[PATCH v3] gen_compile_commands: handle multiple lines per .mod file

[PATCH v3] gen_compile_commands: handle multiple lines per .mod file

[John Hubbard]

scripts/clang-tools/gen_compile_commands.py incorrectly assumes that
each .mod file only contains one line. That assumption was correct when
the script was originally created, but commit 9413e7640564 ("kbuild:
split the second line of *.mod into *.usyms") changed the .mod file
format so that there is one entry per line, and potentially many lines.

The problem can be reproduced by using Kbuild to generate
compile_commands.json, like this:

    make CC=clang compile_commands.json

In many cases, the problem might be overlooked because many subsystems
only have one line anyway. However, in some subsystems (Nouveau, with
762 entries, is a notable example) it results in skipping most of the
subsystem.

Fix this by fully processing each .mod file.

Fixes: 9413e7640564 ("kbuild: split the second line of *.mod into *.usyms")
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---

Link to v2:
https://lore.kernel.org/all/20220616021149.327587-1-jhubbard@nvidia.com/

Changes since v2:

  * Restored a blank line.

  * Rewrote the commit description.

thanks,
John Hubbard


 scripts/clang-tools/gen_compile_commands.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/scripts/clang-tools/gen_compile_commands.py b/scripts/clang-tools/gen_compile_commands.py
index 1d1bde1fd45e..47da25b3ba7d 100755
--- a/scripts/clang-tools/gen_compile_commands.py
+++ b/scripts/clang-tools/gen_compile_commands.py
@@ -157,10 +157,10 @@ def cmdfiles_for_modorder(modorder):
             if ext != '.ko':
                 sys.exit('{}: module path must end with .ko'.format(ko))
             mod = base + '.mod'
-	    # The first line of *.mod lists the objects that compose the module.
+            # Read from *.mod, to get a list of objects that compose the module.
             with open(mod) as m:
-                for obj in m.readline().split():
-                    yield to_cmdfile(obj)
+                for mod_line in m:
+                    yield to_cmdfile(mod_line.rstrip())
 
 
 def process_line(root_directory, command_prefix, file_path):
-- 
2.36.1

Re: [PATCH v3] gen_compile_commands: handle multiple lines per .mod file

[Nick Desaulniers]

On Mon, Jun 27, 2022 at 6:24 PM John Hubbard <jhubbard@nvidia.com> wrote:
>
> scripts/clang-tools/gen_compile_commands.py incorrectly assumes that
> each .mod file only contains one line. That assumption was correct when
> the script was originally created, but commit 9413e7640564 ("kbuild:
> split the second line of *.mod into *.usyms") changed the .mod file
> format so that there is one entry per line, and potentially many lines.
>
> The problem can be reproduced by using Kbuild to generate
> compile_commands.json, like this:
>
>     make CC=clang compile_commands.json
>
> In many cases, the problem might be overlooked because many subsystems
> only have one line anyway. However, in some subsystems (Nouveau, with
> 762 entries, is a notable example) it results in skipping most of the
> subsystem.
>
> Fix this by fully processing each .mod file.
>
> Fixes: 9413e7640564 ("kbuild: split the second line of *.mod into *.usyms")
> Cc: Masahiro Yamada <masahiroy@kernel.org>
> Cc: Nick Desaulniers <ndesaulniers@google.com>

Thanks for the fix, John!
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> ---
>
> Link to v2:
> https://lore.kernel.org/all/20220616021149.327587-1-jhubbard@nvidia.com/
>
> Changes since v2:
>
>   * Restored a blank line.
>
>   * Rewrote the commit description.
>
> thanks,
> John Hubbard
>
>
>  scripts/clang-tools/gen_compile_commands.py | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/scripts/clang-tools/gen_compile_commands.py b/scripts/clang-tools/gen_compile_commands.py
> index 1d1bde1fd45e..47da25b3ba7d 100755
> --- a/scripts/clang-tools/gen_compile_commands.py
> +++ b/scripts/clang-tools/gen_compile_commands.py
> @@ -157,10 +157,10 @@ def cmdfiles_for_modorder(modorder):
>              if ext != '.ko':
>                  sys.exit('{}: module path must end with .ko'.format(ko))
>              mod = base + '.mod'
> -           # The first line of *.mod lists the objects that compose the module.
> +            # Read from *.mod, to get a list of objects that compose the module.
>              with open(mod) as m:
> -                for obj in m.readline().split():
> -                    yield to_cmdfile(obj)
> +                for mod_line in m:
> +                    yield to_cmdfile(mod_line.rstrip())
>
>
>  def process_line(root_directory, command_prefix, file_path):
> --
> 2.36.1
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH v3] gen_compile_commands: handle multiple lines per .mod file

[Masahiro Yamada]

On Wed, Jun 29, 2022 at 3:45 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> On Mon, Jun 27, 2022 at 6:24 PM John Hubbard <jhubbard@nvidia.com> wrote:
> >
> > scripts/clang-tools/gen_compile_commands.py incorrectly assumes that
> > each .mod file only contains one line. That assumption was correct when
> > the script was originally created, but commit 9413e7640564 ("kbuild:
> > split the second line of *.mod into *.usyms") changed the .mod file
> > format so that there is one entry per line, and potentially many lines.
> >
> > The problem can be reproduced by using Kbuild to generate
> > compile_commands.json, like this:
> >
> >     make CC=clang compile_commands.json
> >
> > In many cases, the problem might be overlooked because many subsystems
> > only have one line anyway. However, in some subsystems (Nouveau, with
> > 762 entries, is a notable example) it results in skipping most of the
> > subsystem.
> >
> > Fix this by fully processing each .mod file.
> >
> > Fixes: 9413e7640564 ("kbuild: split the second line of *.mod into *.usyms")
> > Cc: Masahiro Yamada <masahiroy@kernel.org>
> > Cc: Nick Desaulniers <ndesaulniers@google.com>
>
> Thanks for the fix, John!
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>



Applied to linux-kbuild/fixes with Nick's reviewed-by.
Thanks.


-- 
Best Regards
Masahiro Yamada