Re: [PATCH v1] clang_tools:gen_compile_commands: Change the default source directory

[Nathan Chancellor <nathan@kernel.org>]

On Sun, Feb 14, 2021 at 07:49:22PM +0800, Stephen Zhang wrote:
> Masahiro Yamada <masahiroy@kernel.org> 于2021年2月13日周六 下午8:46写道：
> > This is the steps I tested.
> >
> >
> > masahiro@oscar:~/ref/linux$ make O=build  defconfig all -j24
> >   [ snip ]
> > masahiro@oscar:~/ref/linux$
> > ./scripts/clang-tools/gen_compile_commands.py  -d build
> > masahiro@oscar:~/ref/linux$ grep '"file":' compile_commands.json |
> > grep scripts/ | head -n5
> >     "file": "/home/masahiro/ref/linux/scripts/mod/empty.c"
> >     "file": "/home/masahiro/ref/linux/scripts/mod/sumversion.c"
> >     "file": "/home/masahiro/ref/linux/scripts/mod/file2alias.c"
> >     "file": "/home/masahiro/ref/linux/scripts/mod/modpost.c"
> >     "file": "/home/masahiro/ref/linux/build/scripts/kconfig/parser.tab.c"
> >
> > --
> > Best Regards
> > Masahiro Yamada
> 
> Thanks. Nathan had a detailed description about  this:
> 
> > $ make O=build
> >
> > will work with '-d .' because the .cmd files are in '.' and the source
> > files will be placed relative to '.', which is correct. Your command
> > does not work for two reasons:
> >
> > 1. You are using a build directory that is not a subpath of the source
> > directory. In other words, this script would not work for
> >
> > $ make O=/tmp/build
> >
> > because '-d /tmp/build' needs to be used to find the .cmd files but then
> > the relative path of the source files is messed up, as you point out.
> 
> This may help you reproduce the problem. So you shoud try:
> 
> >masahiro@oscar:~/ref/linux$ make O=/tmp/build  defconfig all -j24
> 
> where the build directory  is not a subpath of the source directory.
> 

This will actually work for the regular build system as it uses the full
path to the files when O= is outside of the source tree. My comment
applies only to the tools/ build system, which Masahiro has explicitly
said he does not want this script to support.

Cheers,
Nathan