kbuild: remove top-level built-in.a (dee94953) · Commits · 戴 / test

Documentation/kbuild/makefiles.txt

+2 −7

Original line number	Diff line number	Diff line
		@@ -154,13 +154,8 @@ more details, with real examples.

		Kbuild compiles all the $(obj-y) files. It then calls
		"$(AR) rcSTP" to merge these files into one built-in.a file.
		This is a thin archive without a symbol table, which makes it
		unsuitable as a linker input.

		The scripts/link-vmlinux.sh script later makes an aggregate
		built-in.a with "${AR} rcsTP", which creates the thin archive
		with a symbol table and an index, making it a valid input for
		the final vmlinux link passes.
		This is a thin archive without a symbol table. It will be later
		linked into vmlinux by scripts/link-vmlinux.sh

		The order of files in $(obj-y) is significant. Duplicates in
		the lists are allowed: the first instance will be linked into

scripts/Makefile.build

+2 −6

Original line number	Diff line number	Diff line
		@@ -394,14 +394,10 @@ $(obj)/%.asn1.c $(obj)/%.asn1.h: $(src)/%.asn1 $(objtree)/scripts/asn1_compiler
		$(sort $(subdir-obj-y)): $(subdir-ym) ;

		#
		# Rule to compile a set of .o files into one .o file
		# Rule to compile a set of .o files into one .a file (without symbol table)
		#
		ifdef builtin-target

		# built-in.a archives are made with no symbol table or index which
		# makes them small and fast, but unable to be used by the linker.
		# scripts/link-vmlinux.sh builds an aggregate built-in.a with a symbol
		# table and index.
		quiet_cmd_ar_builtin = AR $@
		cmd_ar_builtin = rm -f $@; \
		$(AR) rcSTP$(KBUILD_ARFLAGS) $@ $(filter $(real-obj-y), $^)
		@@ -426,7 +422,7 @@ $(modorder-target): $(subdir-ym) FORCE
		$(Q)(cat /dev/null; $(modorder-cmds)) > $@

		#
		# Rule to compile a set of .o files into one .a file
		# Rule to compile a set of .o files into one .a file (with symbol table)
		#
		ifdef lib-target
		quiet_cmd_link_l_target = AR $@

scripts/link-vmlinux.sh

+6 −24

Original line number	Diff line number	Diff line
		@@ -44,24 +44,6 @@ info()
		fi
		}

		# 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
		#
		# built-in.a output file
		#
		archive_builtin()
		{
		info AR built-in.a
		rm -f built-in.a;
		${AR} rcsTP${KBUILD_ARFLAGS} built-in.a \
		${KBUILD_VMLINUX_INIT} \
		${KBUILD_VMLINUX_MAIN}
		}

		# Link of vmlinux.o used for section mismatch analysis
		# ${1} output file
		modpost_link()
		@@ -69,7 +51,8 @@ modpost_link()
		local objects

		objects="--whole-archive \
		built-in.a \
		${KBUILD_VMLINUX_INIT} \
		${KBUILD_VMLINUX_MAIN} \
		--no-whole-archive \
		--start-group \
		${KBUILD_VMLINUX_LIBS} \
		@@ -88,7 +71,8 @@ vmlinux_link()

		if [ "${SRCARCH}" != "um" ]; then
		objects="--whole-archive \
		built-in.a \
		${KBUILD_VMLINUX_INIT} \
		${KBUILD_VMLINUX_MAIN} \
		--no-whole-archive \
		--start-group \
		${KBUILD_VMLINUX_LIBS} \
		@@ -99,7 +83,8 @@ vmlinux_link()
		-T ${lds} ${objects}
		else
		objects="-Wl,--whole-archive \
		built-in.a \
		${KBUILD_VMLINUX_INIT} \
		${KBUILD_VMLINUX_MAIN} \
		-Wl,--no-whole-archive \
		-Wl,--start-group \
		${KBUILD_VMLINUX_LIBS} \
		@@ -160,7 +145,6 @@ cleanup()
		rm -f .tmp_System.map
		rm -f .tmp_kallsyms*
		rm -f .tmp_vmlinux*
		rm -f built-in.a
		rm -f System.map
		rm -f vmlinux
		rm -f vmlinux.o
		@@ -217,8 +201,6 @@ fi;
		# final build of init/
		${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init

		archive_builtin

		#link vmlinux.o
		info LD vmlinux.o
		modpost_link vmlinux.o

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