[PATCH 2/2] kbuild: sort hostprogs before passing it to ifneq

From: Masahiro Yamada
Date: Tue Jul 28 2020 - 23:25:11 EST


The conditional:

ifneq ($(hostprogs),)

... is evaluated to true if $(hostprogs) does not contain any word but
whitespace characters.

ifneq ($(strip $(hostprogs)),)

... is a safe way to avoid interpreting whitespace as a non-empty value,
but I'd rather want to use the side-effect of $(sort ...) to do the
equivalent.

$(sort ...) is used in scripts/Makefile.host in order to drop duplication
in $(hostprogs). It is also useful to strip excessive spaces.

Move $(sort ...) before evaluating the ifneq.

Signed-off-by: Masahiro Yamada <masahiroy@xxxxxxxxxx>
---

scripts/Makefile.build | 5 ++++-
scripts/Makefile.host | 10 ++++------
2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index d41c1cd453b9..e0b6b5db11c2 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -45,12 +45,15 @@ include $(kbuild-file)

include scripts/Makefile.lib

-# Do not include hostprogs rules unless needed
+# Do not include hostprogs rules unless needed.
+# $(sort ...) is used here to remove duplicated words and excessive spaces.
+hostprogs := $(sort $(hostprogs))
ifneq ($(hostprogs),)
include scripts/Makefile.host
endif

# Do not include userprogs rules unless needed.
+# $(sort ...) is used here to remove duplicated words and excessive spaces.
userprogs := $(sort $(userprogs))
ifneq ($(userprogs),)
include scripts/Makefile.userprogs
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index 687ca3f309e9..278b4d6ac945 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -38,24 +38,22 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
# Will compile qconf as a C++ program, and menu as a C program.
# They are linked as C++ code to the executable qconf

-__hostprogs := $(sort $(hostprogs))
-
# C code
# Executables compiled from a single .c file
-host-csingle := $(foreach m,$(__hostprogs), \
+host-csingle := $(foreach m,$(hostprogs), \
$(if $($(m)-objs)$($(m)-cxxobjs),,$(m)))

# C executables linked based on several .o files
-host-cmulti := $(foreach m,$(__hostprogs),\
+host-cmulti := $(foreach m,$(hostprogs),\
$(if $($(m)-cxxobjs),,$(if $($(m)-objs),$(m))))

# Object (.o) files compiled from .c files
-host-cobjs := $(sort $(foreach m,$(__hostprogs),$($(m)-objs)))
+host-cobjs := $(sort $(foreach m,$(hostprogs),$($(m)-objs)))

# C++ code
# C++ executables compiled from at least one .cc file
# and zero or more .c files
-host-cxxmulti := $(foreach m,$(__hostprogs),$(if $($(m)-cxxobjs),$(m)))
+host-cxxmulti := $(foreach m,$(hostprogs),$(if $($(m)-cxxobjs),$(m)))

# C++ Object (.o) files compiled from .cc files
host-cxxobjs := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))
--
2.25.1