[PATCH 1/2] kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)

* [PATCH 1/2] kbuild: change *FLAGS_<basetarget>.o to take the path relative to $(obj)
@ 2019-08-25 17:28 ` Masahiro Yamada
  0 siblings, 0 replies; 15+ messages in thread
From: Masahiro Yamada @ 2019-08-25 17:28 UTC (permalink / raw)
  To: linux-kbuild
  Cc: Masahiro Yamada, Andy Lutomirski, Borislav Petkov,
	H. Peter Anvin, Ingo Molnar, James Morse, Julien Thierry,
	Marc Zyngier, Michal Marek, Russell King, Suzuki K Poulose,
	Thomas Gleixner, kvmarm, linux-arm-kernel, linux-kernel, x86

Kbuild provides per-file compiler flag addition/removal:

  CFLAGS_<basetarget>.o
  CFLAGS_REMOVE_<basetarget>.o
  AFLAGS_<basetarget>.o
  AFLAGS_REMOVE_<basetarget>.o
  CPPFLAGS_<basetarget>
  HOSTCFLAGS_<basetarget>.o
  HOSTCXXFLAGS_<basetarget>.o

The <basetarget> is the filename of the target without its suffix.

This syntax comes into a trouble when two files with the same name
appear in one Makefile, for example:

  obj-y += foo.o
  obj-y += dir/foo.o
  CFLAGS_foo.o := <some-flags>

Here, the <some-flags> applies to both foo.o and dir/foo.o

The real world problem is:

  scripts/kconfig/util.c
  scripts/kconfig/lxdialog/util.c

Both files are compiled into scripts/kconfig/mconf, but only the
latter should be given with additional flags for ncurses.

It is more sensible to use the relative path to the Makefile, like this:

  obj-y += foo.o
  CFLAGS_foo.o := <some-flags>
  obj-y += dir/foo.o
  CFLAGS_dir/foo.o := <other-flags>

The $* variable is replaced with the stem ('%') part in a pattern rule.
In other words, this only works for pattern rules.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 arch/arm/kvm/Makefile        |  5 +++--
 arch/x86/entry/vdso/Makefile |  3 ++-
 scripts/Makefile.host        | 30 +++++++++++++++---------------
 scripts/Makefile.lib         | 10 +++++-----
 scripts/kconfig/Makefile     |  8 ++++----
 5 files changed, 29 insertions(+), 27 deletions(-)

diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index 531e59f5be9c..b76b75bd9e00 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -8,13 +8,14 @@ ifeq ($(plus_virt),+virt)
 	plus_virt_def := -DREQUIRES_VIRT=1
 endif
 
+KVM := ../../../virt/kvm
+
 ccflags-y += -I $(srctree)/$(src) -I $(srctree)/virt/kvm/arm/vgic
-CFLAGS_arm.o := $(plus_virt_def)
+CFLAGS_$(KVM)/arm/arm.o := $(plus_virt_def)
 
 AFLAGS_init.o := -Wa,-march=armv7-a$(plus_virt)
 AFLAGS_interrupts.o := -Wa,-march=armv7-a$(plus_virt)
 
-KVM := ../../../virt/kvm
 kvm-arm-y = $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/eventfd.o $(KVM)/vfio.o
 
 obj-$(CONFIG_KVM_ARM_HOST) += hyp/
diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 8df549138193..0f2154106d01 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -89,6 +89,7 @@ $(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS
 #
 CFLAGS_REMOVE_vdso-note.o = -pg
 CFLAGS_REMOVE_vclock_gettime.o = -pg
+CFLAGS_REMOVE_vdso32/vclock_gettime.o = -pg
 CFLAGS_REMOVE_vgetcpu.o = -pg
 CFLAGS_REMOVE_vvar.o = -pg
 
@@ -128,7 +129,7 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE
 $(obj)/vdsox32.so.dbg: $(obj)/vdsox32.lds $(vobjx32s) FORCE
 	$(call if_changed,vdso_and_check)
 
-CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
+CPPFLAGS_vdso32/vdso32.lds = $(CPPFLAGS_vdso.lds)
 VDSO_LDFLAGS_vdso32.lds = -m elf_i386 -soname linux-gate.so.1
 
 targets += vdso32/vdso32.lds
diff --git a/scripts/Makefile.host b/scripts/Makefile.host
index b402c619147d..cd2b98e2f727 100644
--- a/scripts/Makefile.host
+++ b/scripts/Makefile.host
@@ -80,9 +80,9 @@ host-cxxshobjs	:= $(addprefix $(obj)/,$(host-cxxshobjs))
 # Handle options to gcc. Support building with separate output directory
 
 _hostc_flags   = $(KBUILD_HOSTCFLAGS)   $(HOST_EXTRACFLAGS)   \
-                 $(HOSTCFLAGS_$(basetarget).o)
+                 $(HOSTCFLAGS_$*.o)
 _hostcxx_flags = $(KBUILD_HOSTCXXFLAGS) $(HOST_EXTRACXXFLAGS) \
-                 $(HOSTCXXFLAGS_$(basetarget).o)
+                 $(HOSTCXXFLAGS_$*.o)
 
 # $(objtree)/$(obj) for including generated headers from checkin source files
 ifeq ($(KBUILD_EXTMOD),)
@@ -102,7 +102,7 @@ hostcxx_flags  = -Wp,-MD,$(depfile) $(_hostcxx_flags)
 # host-csingle -> Executable
 quiet_cmd_host-csingle 	= HOSTCC  $@
       cmd_host-csingle	= $(HOSTCC) $(hostc_flags) $(KBUILD_HOSTLDFLAGS) -o $@ $< \
-		$(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(@F))
+		$(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$*)
 $(host-csingle): $(obj)/%: $(src)/%.c FORCE
 	$(call if_changed_dep,host-csingle)
 
@@ -110,9 +110,9 @@ $(host-csingle): $(obj)/%: $(src)/%.c FORCE
 # host-cmulti -> executable
 quiet_cmd_host-cmulti	= HOSTLD  $@
       cmd_host-cmulti	= $(HOSTCC) $(KBUILD_HOSTLDFLAGS) -o $@ \
-			  $(addprefix $(obj)/,$($(@F)-objs)) \
-			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(@F))
-$(host-cmulti): FORCE
+			  $(addprefix $(obj)/, $($*-objs)) \
+			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$*)
+$(host-cmulti): $(obj)/%: FORCE
 	$(call if_changed,host-cmulti)
 $(call multi_depend, $(host-cmulti), , -objs)
 
@@ -128,9 +128,9 @@ $(host-cobjs): $(obj)/%.o: $(src)/%.c FORCE
 quiet_cmd_host-cxxmulti	= HOSTLD  $@
       cmd_host-cxxmulti	= $(HOSTCXX) $(KBUILD_HOSTLDFLAGS) -o $@ \
 			  $(foreach o,objs cxxobjs,\
-			  $(addprefix $(obj)/,$($(@F)-$(o)))) \
-			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(@F))
-$(host-cxxmulti): FORCE
+			  $(addprefix $(obj)/, $($*-$(o)))) \
+			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$*)
+$(host-cxxmulti): $(obj)/%: FORCE
 	$(call if_changed,host-cxxmulti)
 $(call multi_depend, $(host-cxxmulti), , -objs -cxxobjs)
 
@@ -161,9 +161,9 @@ $(host-cxxshobjs): $(obj)/%.o: $(src)/%.c FORCE
 # *.o -> .so shared library (host-cshlib)
 quiet_cmd_host-cshlib	= HOSTLLD -shared $@
       cmd_host-cshlib	= $(HOSTCC) $(KBUILD_HOSTLDFLAGS) -shared -o $@ \
-			  $(addprefix $(obj)/,$($(@F:.so=-objs))) \
-			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(@F))
-$(host-cshlib): FORCE
+			  $(addprefix $(obj)/, $($*-objs)) \
+			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$*.so)
+$(host-cshlib): $(obj)/%.so: FORCE
 	$(call if_changed,host-cshlib)
 $(call multi_depend, $(host-cshlib), .so, -objs)
 
@@ -171,9 +171,9 @@ $(call multi_depend, $(host-cshlib), .so, -objs)
 # *.o -> .so shared library (host-cxxshlib)
 quiet_cmd_host-cxxshlib	= HOSTLLD -shared $@
       cmd_host-cxxshlib	= $(HOSTCXX) $(KBUILD_HOSTLDFLAGS) -shared -o $@ \
-			  $(addprefix $(obj)/,$($(@F:.so=-objs))) \
-			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(@F))
-$(host-cxxshlib): FORCE
+			  $(addprefix $(obj)/, $($*-objs)) \
+			  $(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$*.so)
+$(host-cxxshlib): $(obj)/%.so: FORCE
 	$(call if_changed,host-cxxshlib)
 $(call multi_depend, $(host-cxxshlib), .so, -objs)
 
diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 264611972c4a..0d48e17bfb07 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -109,12 +109,12 @@ basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget))
 modname_flags  = -DKBUILD_MODNAME=$(call name-fix,$(modname))
 
 orig_c_flags   = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) \
-                 $(ccflags-y) $(CFLAGS_$(basetarget).o)
-_c_flags       = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
+                 $(ccflags-y) $(CFLAGS_$*.o)
+_c_flags       = $(filter-out $(CFLAGS_REMOVE_$*.o), $(orig_c_flags))
 orig_a_flags   = $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) \
-                 $(asflags-y) $(AFLAGS_$(basetarget).o)
-_a_flags       = $(filter-out $(AFLAGS_REMOVE_$(basetarget).o), $(orig_a_flags))
-_cpp_flags     = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))
+                 $(asflags-y) $(AFLAGS_$*.o)
+_a_flags       = $(filter-out $(AFLAGS_REMOVE_$*.o), $(orig_a_flags))
+_cpp_flags     = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$*.lds)
 
 #
 # Enable gcov profiling flags for a file, directory or for all files depending
diff --git a/scripts/kconfig/Makefile b/scripts/kconfig/Makefile
index bed7a5a2fbe9..ef2f2336c469 100644
--- a/scripts/kconfig/Makefile
+++ b/scripts/kconfig/Makefile
@@ -166,15 +166,15 @@ $(obj)/nconf.o $(obj)/nconf.gui.o: $(obj)/nconf-cfg
 
 # mconf: Used for the menuconfig target based on lxdialog
 hostprogs-y	+= mconf
-lxdialog	:= checklist.o inputbox.o menubox.o textbox.o util.o yesno.o
-mconf-objs	:= mconf.o $(addprefix lxdialog/, $(lxdialog)) $(common-objs)
+lxdialog	:= $(addprefix lxdialog/, \
+		     checklist.o inputbox.o menubox.o textbox.o util.o yesno.o)
+mconf-objs	:= mconf.o $(lxdialog) $(common-objs)
 
 HOSTLDLIBS_mconf = $(shell . $(obj)/mconf-cfg && echo $$libs)
 $(foreach f, mconf.o $(lxdialog), \
   $(eval HOSTCFLAGS_$f = $$(shell . $(obj)/mconf-cfg && echo $$$$cflags)))
 
-$(obj)/mconf.o: $(obj)/mconf-cfg
-$(addprefix $(obj)/lxdialog/, $(lxdialog)): $(obj)/mconf-cfg
+$(addprefix $(obj)/, mconf.o $(lxdialog)): $(obj)/mconf-cfg
 
 # qconf: Used for the xconfig target based on Qt
 hostprogs-y	+= qconf
-- 
2.17.1


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