Kbuild: fix # escaping in .cmd files for future Make

commit 9564a8cf422d7b58f6e857e3546d346fa970191e upstream.

I tried building using a freshly built Make (4.2.1-69-g8a731d1), but
already the objtool build broke with

orc_dump.c: In function ‘orc_dump’:
orc_dump.c:106:2: error: ‘elf_getshnum’ is deprecated [-Werror=deprecated-declarations]
  if (elf_getshdrnum(elf, &nr_sections)) {

Turns out that with that new Make, the backslash was not removed, so cpp
didn't see a #include directive, grep found nothing, and
-DLIBELF_USE_DEPRECATED was wrongly put in CFLAGS.

Now, that new Make behaviour is documented in their NEWS file:

  * WARNING: Backward-incompatibility!
    Number signs (#) appearing inside a macro reference or function invocation
    no longer introduce comments and should not be escaped with backslashes:
    thus a call such as:
      foo := $(shell echo '#')
    is legal.  Previously the number sign needed to be escaped, for example:
      foo := $(shell echo '\#')
    Now this latter will resolve to "\#".  If you want to write makefiles
    portable to both versions, assign the number sign to a variable:
      C := \#
      foo := $(shell echo '$C')
    This was claimed to be fixed in 3.81, but wasn't, for some reason.
    To detect this change search for 'nocomment' in the .FEATURES variable.

This also fixes up the two make-cmd instances to replace # with $(pound)
rather than with \#. There might very well be other places that need
similar fixup in preparation for whatever future Make release contains
the above change, but at least this builds an x86_64 defconfig with the
new make.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=197847
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 1db6d73c8dd2bdfeec2cae452dffc8791b3ef645..31a981d6229d291887c25a71dc7fc3d8da6d42f1 100644 (file)
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -7,6 +7,7 @@ quote   := "
 squote  := '
 empty   :=
 space   := $(empty) $(empty)
+pound   := \#
 
 ###
 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
@@ -236,11 +237,11 @@ endif
 
 # Replace >$< with >$$< to preserve $ when reloading the .cmd file
 # (needed for make)
-# Replace >#< with >\#< to avoid starting a comment in the .cmd file
+# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
 # (needed for make)
 # Replace >'< with >'\''< to be able to enclose the whole string in '...'
 # (needed for the shell)
-make-cmd = $(call escsq,$(subst \#,\\\#,$(subst $$,$$$$,$(cmd_$(1)))))
+make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
 
 # Find any prerequisites that is newer than target or that does not exist.
 # PHONY targets skipped in both cases.

diff --git a/tools/build/Build.include b/tools/build/Build.include
index 1c570528baf7d10060ce32ded1fd9ab5ae65c602..0340d8a51daba8f699fd3d1847c91b4f8073f9a2 100644 (file)
--- a/tools/build/Build.include
+++ b/tools/build/Build.include
@@ -12,6 +12,7 @@
 # Convenient variables
 comma   := ,
 squote  := '
+pound   := \#
 
 ###
 # Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
@@ -43,11 +44,11 @@ echo-cmd = $(if $($(quiet)cmd_$(1)),\
 ###
 # Replace >$< with >$$< to preserve $ when reloading the .cmd file
 # (needed for make)
-# Replace >#< with >\#< to avoid starting a comment in the .cmd file
+# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
 # (needed for make)
 # Replace >'< with >'\''< to be able to enclose the whole string in '...'
 # (needed for the shell)
-make-cmd = $(call escsq,$(subst \#,\\\#,$(subst $$,$$$$,$(cmd_$(1)))))
+make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
 
 ###
 # Find any prerequisites that is newer than target or that does not exist.

diff --git a/tools/scripts/Makefile.include b/tools/scripts/Makefile.include
index 19edc1a7a232269726a55992200685f77675a9b9..7ea4438b801ddb700f070c3e6d843305434185d0 100644 (file)
--- a/tools/scripts/Makefile.include
+++ b/tools/scripts/Makefile.include
@@ -92,3 +92,5 @@ ifneq ($(silent),1)
        QUIET_INSTALL  = @printf '  INSTALL  %s\n' $1;
   endif
 endif
+
+pound := \#