linux.git/scripts/genksyms/Makefile, branch v6.12.80

kbuild: use $(src) instead of $(srctree)/$(src) for source directory

2024-05-09T19:34:52+00:00

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

    src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

  $(obj)     - directory in the object tree
  $(src)     - directory in the source tree  (changed by this commit)
  $(objtree) - the top of the kernel object tree
  $(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada 
Reviewed-by: Nicolas Schier

genksyms: fix stale comment

2021-05-01T15:43:34+00:00

(shipped source) is a stale comment.

Since commit 833e62245943 ("genksyms: generate lexer and parser during
build instead of shipping"), there is no source file to be shipped in
this directory.

Signed-off-by: Masahiro Yamada

kbuild: introduce hostprogs-always-y and userprogs-always-y

2020-08-09T16:32:59+00:00

To build host programs, you need to add the program names to 'hostprogs'
to use the necessary build rule, but it is not enough to build them
because there is no dependency.

There are two types of host programs: built as the prerequisite of
another (e.g. gen_crc32table in lib/Makefile), or always built when
Kbuild visits the Makefile (e.g. genksyms in scripts/genksyms/Makefile).

The latter is typical in Makefiles under scripts/, which contains host
programs globally used during the kernel build. To build them, you need
to add them to both 'hostprogs' and 'always-y'.

This commit adds hostprogs-always-y as a shorthand.

The same applies to user programs. net/bpfilter/Makefile builds
bpfilter_umh on demand, hence always-y is unneeded. In contrast,
programs under samples/ are added to both 'userprogs' and 'always-y'
so they are always built when Kbuild visits the Makefiles.

userprogs-always-y works as a shorthand.

Signed-off-by: Masahiro Yamada 
Acked-by: Miguel Ojeda

kbuild: rename hostprogs-y/always to hostprogs/always-y

2020-02-03T16:53:07+00:00

In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.

It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.

This commit renames like follows:

  always       ->  always-y
  hostprogs-y  ->  hostprogs

So, scripts/Makefile will look like this:

  always-$(CONFIG_BUILD_BIN2C) += ...
  always-$(CONFIG_KALLSYMS)    += ...
      ...
  hostprogs := $(always-y) $(always-m)

I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.

The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.

Signed-off-by: Masahiro Yamada

kbuild: rename KBUILD_ENABLE_EXTRA_GCC_CHECKS to KBUILD_EXTRA_WARN

2019-09-06T14:46:52+00:00

KBUILD_ENABLE_EXTRA_GCC_CHECKS started as a switch to add extra warning
options for GCC, but now it is a historical misnomer since we use it
also for Clang, DTC, and even kernel-doc.

Rename it to more sensible, shorter KBUILD_EXTRA_WARN.

For the backward compatibility, KBUILD_ENABLE_EXTRA_GCC_CHECKS is still
supported (but not advertised in the documentation).

I also fixed up 'make help', and updated the documentation.

Signed-off-by: Masahiro Yamada 
Reviewed-by: Nathan Chancellor 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Sedat Dilek

kbuild: make bison create C file and header in a single pattern rule

2019-08-13T16:10:42+00:00

We generally expect bison to create not only a C file, but also a
header, which will be included from the lexer.

Currently, Kbuild generates them in separate rules. So, for instance,
when building Kconfig, you will notice bison is invoked twice:

  HOSTCC  scripts/kconfig/conf.o
  HOSTCC  scripts/kconfig/confdata.o
  HOSTCC  scripts/kconfig/expr.o
  LEX     scripts/kconfig/lexer.lex.c
  YACC    scripts/kconfig/parser.tab.h
  HOSTCC  scripts/kconfig/lexer.lex.o
  YACC    scripts/kconfig/parser.tab.c
  HOSTCC  scripts/kconfig/parser.tab.o
  HOSTCC  scripts/kconfig/preprocess.o
  HOSTCC  scripts/kconfig/symbol.o
  HOSTLD  scripts/kconfig/conf

Make handles such cases nicely in pattern rules [1]. Merge the two
rules so that one invokcation of bison can generate both of them.

  HOSTCC  scripts/kconfig/conf.o
  HOSTCC  scripts/kconfig/confdata.o
  HOSTCC  scripts/kconfig/expr.o
  LEX     scripts/kconfig/lexer.lex.c
  YACC    scripts/kconfig/parser.tab.[ch]
  HOSTCC  scripts/kconfig/lexer.lex.o
  HOSTCC  scripts/kconfig/parser.tab.o
  HOSTCC  scripts/kconfig/preprocess.o
  HOSTCC  scripts/kconfig/symbol.o
  HOSTLD  scripts/kconfig/conf

[1] Pattern rule

GNU Make manual says:
"Pattern rules may have more than one target. Unlike normal rules,
this does not act as many different rules with the same prerequisites
and recipe. If a pattern rule has multiple targets, make knows that
the rule's recipe is responsible for making all of the targets. The
recipe is executed only once to make all the targets. When searching
for a pattern rule to match a target, the target patterns of a rule
other than the one that matches the target in need of a rule are
incidental: make worries only about giving a recipe and prerequisites
to the file presently in question. However, when this file's recipe is
run, the other targets are marked as having been updated themselves."

https://www.gnu.org/software/make/manual/html_node/Pattern-Intro.html

Signed-off-by: Masahiro Yamada

treewide: prefix header search paths with $(srctree)/

2019-05-18T02:49:57+00:00

Currently, the Kbuild core manipulates header search paths in a crazy
way [1].

To fix this mess, I want all Makefiles to add explicit $(srctree)/ to
the search paths in the srctree. Some Makefiles are already written in
that way, but not all. The goal of this work is to make the notation
consistent, and finally get rid of the gross hacks.

Having whitespaces after -I does not matter since commit 48f6e3cf5bc6
("kbuild: do not drop -I without parameter").

[1]: https://patchwork.kernel.org/patch/9632347/

Signed-off-by: Masahiro Yamada

genksyms: fix typo in parse.tab.{c,h} generation rules

2018-05-05T01:24:53+00:00

'quet' is replaced by 'quiet' in scripts/genksyms/Makefile

Signed-off-by: Mauro Rossi 
Signed-off-by: Masahiro Yamada

kbuild: add %.lex.c and %.tab.[ch] to 'targets' automatically

2018-04-07T10:04:02+00:00

Files generated by if_changed* must be added to 'targets' to include
*.cmd files.  Otherwise, they would be regenerated every time.

The build system automatically adds objects to 'targets' where
appropriate, such as obj-y, extra-y, etc. but does nothing for
intermediate files.  So, each Makefile needs to add them by itself.

There are some common cases where objects are generated by chained
rules.  Lexers and parsers are compiled like follows:

   %.lex.o <- %.lex.c <- %.l
   %.tab.o <- %.tab.c <- %.y

They are common patterns, so it is reasonable to take care of them
in the core Makefile instead of requiring each Makefile to do so.

At this moment, you cannot delete 'target += zconf.lex.c' in the
Kconfig Makefile because zconf.lex.c is included from zconf.tab.c
instead of being compiled separately.  It should be deleted after
Kconfig is more refactored.

Signed-off-by: Masahiro Yamada 
Acked-by: Frank Rowand

genksyms: generate lexer and parser during build instead of shipping

2018-04-07T10:04:02+00:00

Now that the kernel build supports flex and bison, remove the _shipped
files and generate them during the build instead.

There are no more shipped lexer and parser, so I ripped off the rules
in scripts/Malefile.lib that were used for REGENERATE_PARSERS.

The genksyms parser has ambiguous grammar, which would emit warnings:

 scripts/genksyms/parse.y: warning: 9 shift/reduce conflicts [-Wconflicts-sr]
 scripts/genksyms/parse.y: warning: 5 reduce/reduce conflicts [-Wconflicts-rr]

They are normally suppressed, but displayed when W=1 is given.

Signed-off-by: Masahiro Yamada