Merge tag 'kbuild-thinar-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild thin archives updates from Masahiro Yamada:
 "Thin archives migration by Nicholas Piggin.

  THIN_ARCHIVES has been available for a while as an optional feature
  only for PowerPC architecture, but we do not need two different
  intermediate-artifact schemes.

  Using thin archives instead of conventional incremental linking has
  various advantages:

   - save disk space for builds

   - speed-up building a little

   - fix some link issues (for example, allyesconfig on ARM) due to more
     flexibility for the final linking

   - work better with dead code elimination we are planning

  As discussed before, this migration has been done unconditionally so
  that any problems caused by this will show up with "git bisect".

  With testing with 0-day and linux-next, some architectures actually
  showed up problems, but they were trivial and all fixed now"

* tag 'kbuild-thinar-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  tile: remove unneeded extra-y in Makefile
  kbuild: thin archives make default for all archs
  x86/um: thin archives build fix
  tile: thin archives fix linking
  ia64: thin archives fix linking
  sh: thin archives fix linking
  kbuild: handle libs-y archives separately from built-in.o archives
  kbuild: thin archives use P option to ar
  kbuild: thin archives final link close --whole-archives option
  ia64: remove unneeded extra-y in Makefile.gate
  tile: fix dependency and .*.cmd inclusion for incremental build
  sparc64: Use indirect calls in hamming weight stubs

2 files changed, 41 insertions, 14 deletions

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index 733e044fff8b..4a9a2cec0a1b 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -437,8 +437,8 @@ $(sort $(subdir-obj-y)): $(subdir-ym) ;
 ifdef builtin-target
 
 ifdef CONFIG_THIN_ARCHIVES
-  cmd_make_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
-  cmd_make_empty_builtin = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS)
+  cmd_make_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
+  cmd_make_empty_builtin = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS)
   quiet_cmd_link_o_target = AR      $@
 else
   cmd_make_builtin = $(LD) $(ld_flags) -r -o
@@ -478,7 +478,7 @@ ifdef lib-target
 quiet_cmd_link_l_target = AR      $@
 
 ifdef CONFIG_THIN_ARCHIVES
-  cmd_link_l_target = rm -f $@; $(AR) rcsT$(KBUILD_ARFLAGS) $@ $(lib-y)
+  cmd_link_l_target = rm -f $@; $(AR) rcsTP$(KBUILD_ARFLAGS) $@ $(lib-y)
 else
   cmd_link_l_target = rm -f $@; $(AR) rcs$(KBUILD_ARFLAGS) $@ $(lib-y)
 endif
@@ -531,7 +531,7 @@ cmd_link_multi-link = $(LD) $(ld_flags) -r -o $@ $(link_multi_deps) $(cmd_secana
 
 ifdef CONFIG_THIN_ARCHIVES
   quiet_cmd_link_multi-y = AR      $@
-  cmd_link_multi-y = rm -f $@; $(AR) rcST$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
+  cmd_link_multi-y = rm -f $@; $(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(link_multi_deps)
 else
   quiet_cmd_link_multi-y = LD      $@
   cmd_link_multi-y = $(cmd_link_multi-link)
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index c80291319cb2..e7b7eee31538 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -3,9 +3,12 @@
 # link vmlinux
 #
 # vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_INIT) and
-# $(KBUILD_VMLINUX_MAIN). Most are built-in.o files from top-level directories
-# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
-# Ordering when linking is important, and $(KBUILD_VMLINUX_INIT) must be first.
+# $(KBUILD_VMLINUX_MAIN) and $(KBUILD_VMLINUX_LIBS). Most are built-in.o files
+# from top-level directories in the kernel tree, others are specified in
+# arch/$(ARCH)/Makefile. Ordering when linking is important, and
+# $(KBUILD_VMLINUX_INIT) must be first. $(KBUILD_VMLINUX_LIBS) are archives
+# which are linked conditionally (not within --whole-archive), and do not
+# require symbol indexes added.
 #
 # vmlinux
 #   ^
@@ -16,6 +19,9 @@
 #   +--< $(KBUILD_VMLINUX_MAIN)
 #   |    +--< drivers/built-in.o mm/built-in.o + more
 #   |
+#   +--< $(KBUILD_VMLINUX_LIBS)
+#   |    +--< lib/lib.a + more
+#   |
 #   +-< ${kallsymso} (see description in KALLSYMS section)
 #
 # vmlinux version (uname -v) cannot be updated during normal
@@ -37,9 +43,10 @@ info()
 	fi
 }
 
-# Thin archive build here makes a final archive with
-# symbol table and indexes from vmlinux objects, which can be
-# used as input to linker.
+# Thin archive build here makes a final archive with symbol table and indexes
+# from vmlinux objects INIT and MAIN, which can be used as input to linker.
+# KBUILD_VMLINUX_LIBS archives should already have symbol table and indexes
+# added.
 #
 # Traditional incremental style of link does not require this step
 #
@@ -50,7 +57,7 @@ archive_builtin()
 	if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
 		info AR built-in.o
 		rm -f built-in.o;
-		${AR} rcsT${KBUILD_ARFLAGS} built-in.o			\
+		${AR} rcsTP${KBUILD_ARFLAGS} built-in.o			\
 					${KBUILD_VMLINUX_INIT}		\
 					${KBUILD_VMLINUX_MAIN}
 	fi
@@ -63,11 +70,17 @@ modpost_link()
 	local objects
 
 	if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
-		objects="--whole-archive built-in.o"
+		objects="--whole-archive				\
+			built-in.o					\
+			--no-whole-archive				\
+			--start-group					\
+			${KBUILD_VMLINUX_LIBS}				\
+			--end-group"
 	else
 		objects="${KBUILD_VMLINUX_INIT}				\
 			--start-group					\
 			${KBUILD_VMLINUX_MAIN}				\
+			${KBUILD_VMLINUX_LIBS}				\
 			--end-group"
 	fi
 	${LD} ${LDFLAGS} -r -o ${1} ${objects}
@@ -83,11 +96,18 @@ vmlinux_link()
 
 	if [ "${SRCARCH}" != "um" ]; then
 		if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
-			objects="--whole-archive built-in.o ${1}"
+			objects="--whole-archive			\
+				built-in.o				\
+				--no-whole-archive			\
+				--start-group				\
+				${KBUILD_VMLINUX_LIBS}			\
+				--end-group				\
+				${1}"
 		else
 			objects="${KBUILD_VMLINUX_INIT}			\
 				--start-group				\
 				${KBUILD_VMLINUX_MAIN}			\
+				${KBUILD_VMLINUX_LIBS}			\
 				--end-group				\
 				${1}"
 		fi
@@ -96,11 +116,18 @@ vmlinux_link()
 			-T ${lds} ${objects}
 	else
 		if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
-			objects="-Wl,--whole-archive built-in.o ${1}"
+			objects="-Wl,--whole-archive			\
+				built-in.o				\
+				-Wl,--no-whole-archive			\
+				-Wl,--start-group			\
+				${KBUILD_VMLINUX_LIBS}			\
+				-Wl,--end-group				\
+				${1}"
 		else
 			objects="${KBUILD_VMLINUX_INIT}			\
 				-Wl,--start-group			\
 				${KBUILD_VMLINUX_MAIN}			\
+				${KBUILD_VMLINUX_LIBS}			\
 				-Wl,--end-group				\
 				${1}"
 		fi