Re: [PATCH 1/3] handling of _shipped files

[Randy Dunlap <rdunlap@infradead.org>]

On 10/01/14 06:36, Nicholas Mc Guire wrote:
> 
> handling of _shipped files
> 
> This adds a section on handling of _shipped files in kbuild
> Makefiles and the build process.
> 
> Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
> ---
>  Documentation/kbuild/makefiles.txt |   57 +++++++++++++++++++++++++++++++++++-
>  1 file changed, 56 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/kbuild/makefiles.txt b/Documentation/kbuild/makefiles.txt
> index 764f599..d0bd91a 100644
> --- a/Documentation/kbuild/makefiles.txt
> +++ b/Documentation/kbuild/makefiles.txt
> @@ -19,6 +19,7 @@ This document describes the Linux kernel Makefiles.
>  	   --- 3.10 Special Rules
>  	   --- 3.11 $(CC) support functions
>  	   --- 3.12 $(LD) support functions
> +	   --- 3.13 _shipped - generated files
>  
>  	=== 4 Host Program support
>  	   --- 4.1 Simple Host Program
> @@ -595,6 +596,60 @@ more details, with real examples.
>  		LDFLAGS_vmlinux += $(call ld-option, -X)
>  
>  
> +--- 3.13 _shipped - generated files
> +
> +   Some sources in the kernel are generated by tools or special
> +   purpose scrips so that the build process dependencies can be kept

              scripts

> +   at a resonable level. Also in cases where the translation is not

           reasonable
 
> +   configuration dependent but might impact build time _shipped files

                                               build time,

> +   may be added along with the actual sources to speed up the build
> +   process.
> +
> +   For standard tools like lex and yacc the make process will actually
> +   generate the _shipped files (see scripts/Makefile.lib) and retain
> +   them by marking them .PRECIOUS so they are not removed by the clean
> +   targets.
> +
> +   For non standard tools the generation of the _shipped file it self

          non-standard                                           itself

> +   may be manually achived by building and then renaming. A makefile

                      achieved

> +   target for generate the actual target file should to be provided

             to generate

> +   though and can be conditioned on an environment variable.

Most examples that I see just expect the Makefile to be modified to set
(or define) the variable.

> +
> +	Example:
> +		ifdef GENERATE_KEYMAP
> +
> +		$(obj)/defkeymap.c: $(obj)/%.c: $(src)/%.map
> +			loadkeys --mktable $< > $@
> +
> +		endif
> +
> +   The _shipped file does not appear in the actual Makefile, this is
> +   handled by the rules found in scripts/Makefile.lib.
> +
> +		<snip>
> +		cmd_shipped = cat $< > $@
> +
> +		$(obj)/%: $(src)/%_shipped
> +			$(call cmd,shipped)
> +		<snip>
> +
> +   which simply will copy the target_shipped to the target
> +
> +   If a file of a make target is found in the build directory with the
> +   extension _shipped make will used it, rather than generating the

                _shipped, make will use it rather than generating the

> +   respective target file from source.
> +
> +   The build will indicate the use of the _shipped file by the SHIPPED
> +   quiet command in the make output.
> +
> +	Example:
> +		LD      drivers/scsi/aic7xxx/built-in.o
> +		SHIPPED drivers/scsi/aic7xxx/aic79xx_seq.h
> +		SHIPPED drivers/scsi/aic7xxx/aic79xx_reg.h
> +		CC [M]  drivers/scsi/aic7xxx/aic79xx_core.o
> +		CC [M]  drivers/scsi/aic7xxx/aic79xx_pci.o
> +		SHIPPED drivers/scsi/aic7xxx/aic79xx_reg_print.c
> +		CC [M]  drivers/scsi/aic7xxx/aic79xx_reg_print.o
>  === 4 Host Program support
>  
>  Kbuild supports building executables on the host for use during the
> @@ -1423,10 +1478,10 @@ Original version made by Michael Elizabeth Chastain, <mailto:mec@shout.net>
>  Updates by Kai Germaschewski <kai@tp1.ruhr-uni-bochum.de>
>  Updates by Sam Ravnborg <sam@ravnborg.org>
>  Language QA by Jan Engelhardt <jengelh@gmx.de>
> +Kbuild support for shipped files Nicholas Mc Guire <der.herr@hofr.at>
>  
>  === 11 TODO
>  
> -- Describe how kbuild supports shipped files with _shipped.
>  - Generating offset header files.
>  - Add more variables to section 7?
>  
> 


-- 
~Randy