kbuild: strip whitespace in cmd_record_mcount findstring

CC_FLAGS_FTRACE may contain trailing whitespace that interferes with
findstring.

For example, commit 5880e8df6210 ("powerpc: avoid -mno-sched-epilog on
GCC 4.9 and newer") introduced a change such that on my ppc64le box,
CC_FLAGS_FTRACE="-pg -mprofile-kernel ".  (Note the trailing space.)
When cmd_record_mcount is now invoked, findstring fails as the ftrace
flags were found at very end of _c_flags, without the trailing space.

  _c_flags=" ... -pg -mprofile-kernel"
  CC_FLAGS_FTRACE="-pg -mprofile-kernel "
                                       ^
    findstring is looking for this extra space

Remove the redundant whitespaces from CC_FLAGS_FTRACE in
cmd_record_mcount to avoid this problem.

[masahiro.yamada: This issue only happens in the released versions
of GNU Make. CC_FLAGS_FTRACE will not contain the trailing space if
you use the latest GNU Make, which contains commit b90fabc8d6f3
("* NEWS: Do not insert a space during '+=' if the value is empty.") ]

Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> (refactoring)
Fixes: 5880e8df6210 ("powerpc: avoid -mno-sched-epilog on GCC 4.9 and newer").
Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 2554a15ecf2b8796c41e593d97c8b55ee97a4620..76ca30cc4791912fde4d7f36e4a90549e653cfbb 100644 (file)
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -199,11 +199,8 @@ sub_cmd_record_mcount = perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
        "$(if $(part-of-module),1,0)" "$(@)";
 recordmcount_source := $(srctree)/scripts/recordmcount.pl
 endif # BUILD_C_RECORDMCOUNT
-cmd_record_mcount =                                            \
-       if [ "$(findstring $(CC_FLAGS_FTRACE),$(_c_flags))" =   \
-            "$(CC_FLAGS_FTRACE)" ]; then                       \
-               $(sub_cmd_record_mcount)                        \
-       fi
+cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)),        \
+       $(sub_cmd_record_mcount))
 endif # CC_USING_RECORD_MCOUNT
 endif # CONFIG_FTRACE_MCOUNT_RECORD