Commit 62e22107 authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Michal Marek

kbuild: drop shared library support from Makefile.host

The shared library feature in Makefile.host is no longer used.
Rip it off to keep the build infrastucture simple.

Update Documentation/kbuild/makefiles.txt too.
The section "4.3 Definition shared libraries" should be removed
and the following sections should be re-numbered.
Signed-off-by: default avatarMasahiro Yamada <yamada.m@jp.panasonic.com>
Suggested-by: default avatarSam Ravnborg <sam@ravnborg.org>
Signed-off-by: default avatarMichal Marek <mmarek@suse.cz>
parent edb950c1
......@@ -23,11 +23,10 @@ This document describes the Linux kernel Makefiles.
=== 4 Host Program support
--- 4.1 Simple Host Program
--- 4.2 Composite Host Programs
--- 4.3 Defining shared libraries
--- 4.4 Using C++ for host programs
--- 4.5 Controlling compiler options for host programs
--- 4.6 When host programs are actually built
--- 4.7 Using hostprogs-$(CONFIG_FOO)
--- 4.3 Using C++ for host programs
--- 4.4 Controlling compiler options for host programs
--- 4.5 When host programs are actually built
--- 4.6 Using hostprogs-$(CONFIG_FOO)
=== 5 Kbuild clean infrastructure
......@@ -643,29 +642,7 @@ Both possibilities are described in the following.
Finally, the two .o files are linked to the executable, lxdialog.
Note: The syntax <executable>-y is not permitted for host-programs.
--- 4.3 Defining shared libraries
Objects with extension .so are considered shared libraries, and
will be compiled as position independent objects.
Kbuild provides support for shared libraries, but the usage
shall be restricted.
In the following example the libkconfig.so shared library is used
to link the executable conf.
Example:
#scripts/kconfig/Makefile
hostprogs-y := conf
conf-objs := conf.o libkconfig.so
libkconfig-objs := expr.o type.o
Shared libraries always require a corresponding -objs line, and
in the example above the shared library libkconfig is composed by
the two objects expr.o and type.o.
expr.o and type.o will be built as position independent code and
linked as a shared library libkconfig.so. C++ is not supported for
shared libraries.
--- 4.4 Using C++ for host programs
--- 4.3 Using C++ for host programs
kbuild offers support for host programs written in C++. This was
introduced solely to support kconfig, and is not recommended
......@@ -688,7 +665,7 @@ Both possibilities are described in the following.
qconf-cxxobjs := qconf.o
qconf-objs := check.o
--- 4.5 Controlling compiler options for host programs
--- 4.4 Controlling compiler options for host programs
When compiling host programs, it is possible to set specific flags.
The programs will always be compiled utilising $(HOSTCC) passed
......@@ -716,7 +693,7 @@ Both possibilities are described in the following.
When linking qconf, it will be passed the extra option
"-L$(QTDIR)/lib".
--- 4.6 When host programs are actually built
--- 4.5 When host programs are actually built
Kbuild will only build host-programs when they are referenced
as a prerequisite.
......@@ -747,7 +724,7 @@ Both possibilities are described in the following.
This will tell kbuild to build lxdialog even if not referenced in
any rule.
--- 4.7 Using hostprogs-$(CONFIG_FOO)
--- 4.6 Using hostprogs-$(CONFIG_FOO)
A typical pattern in a Kbuild file looks like this:
......
......@@ -20,16 +20,6 @@
# Will compile qconf as a C++ program, and menu as a C program.
# They are linked as C++ code to the executable qconf
# hostprogs-y := conf
# conf-objs := conf.o libkconfig.so
# libkconfig-objs := expr.o type.o
# Will create a shared library named libkconfig.so that consists of
# expr.o and type.o (they are both compiled as C code and the object files
# are made as position independent code).
# conf.c is compiled as a C program, and conf.o is linked together with
# libkconfig.so as the executable conf.
# Note: Shared libraries consisting of C++ files are not supported
__hostprogs := $(sort $(hostprogs-y) $(hostprogs-m))
# C code
......@@ -52,15 +42,6 @@ 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)))
# Shared libaries (only .c supported)
# Shared libraries (.so) - all .so files referenced in "xxx-objs"
host-cshlib := $(sort $(filter %.so, $(host-cobjs)))
# Remove .so files from "xxx-objs"
host-cobjs := $(filter-out %.so,$(host-cobjs))
#Object (.o) files used by the shared libaries
host-cshobjs := $(sort $(foreach m,$(host-cshlib),$($(m:.so=-objs))))
# output directory for programs/.o files
# hostprogs-y := tools/build may have been specified. Retrieve directory
host-objdirs := $(foreach f,$(__hostprogs), $(if $(dir $(f)),$(dir $(f))))
......@@ -82,8 +63,6 @@ host-cmulti := $(addprefix $(obj)/,$(host-cmulti))
host-cobjs := $(addprefix $(obj)/,$(host-cobjs))
host-cxxmulti := $(addprefix $(obj)/,$(host-cxxmulti))
host-cxxobjs := $(addprefix $(obj)/,$(host-cxxobjs))
host-cshlib := $(addprefix $(obj)/,$(host-cshlib))
host-cshobjs := $(addprefix $(obj)/,$(host-cshobjs))
host-objdirs := $(addprefix $(obj)/,$(host-objdirs))
obj-dirs += $(host-objdirs)
......@@ -124,7 +103,7 @@ quiet_cmd_host-cmulti = HOSTLD $@
cmd_host-cmulti = $(HOSTCC) $(HOSTLDFLAGS) -o $@ \
$(addprefix $(obj)/,$($(@F)-objs)) \
$(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
$(host-cmulti): $(obj)/%: $(host-cobjs) $(host-cshlib) FORCE
$(host-cmulti): $(obj)/%: $(host-cobjs) FORCE
$(call if_changed,host-cmulti)
# Create .o file from a single .c file
......@@ -141,7 +120,7 @@ quiet_cmd_host-cxxmulti = HOSTLD $@
$(foreach o,objs cxxobjs,\
$(addprefix $(obj)/,$($(@F)-$(o)))) \
$(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
$(host-cxxmulti): $(obj)/%: $(host-cobjs) $(host-cxxobjs) $(host-cshlib) FORCE
$(host-cxxmulti): $(obj)/%: $(host-cobjs) $(host-cxxobjs) FORCE
$(call if_changed,host-cxxmulti)
# Create .o file from a single .cc (C++) file
......@@ -150,21 +129,5 @@ quiet_cmd_host-cxxobjs = HOSTCXX $@
$(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
$(call if_changed_dep,host-cxxobjs)
# Compile .c file, create position independent .o file
# host-cshobjs -> .o
quiet_cmd_host-cshobjs = HOSTCC -fPIC $@
cmd_host-cshobjs = $(HOSTCC) $(hostc_flags) -fPIC -c -o $@ $<
$(host-cshobjs): $(obj)/%.o: $(src)/%.c FORCE
$(call if_changed_dep,host-cshobjs)
# Link a shared library, based on position independent .o files
# *.o -> .so shared library (host-cshlib)
quiet_cmd_host-cshlib = HOSTLLD -shared $@
cmd_host-cshlib = $(HOSTCC) $(HOSTLDFLAGS) -shared -o $@ \
$(addprefix $(obj)/,$($(@F:.so=-objs))) \
$(HOST_LOADLIBES) $(HOSTLOADLIBES_$(@F))
$(host-cshlib): $(obj)/%: $(host-cshobjs) FORCE
$(call if_changed,host-cshlib)
targets += $(host-csingle) $(host-cmulti) $(host-cobjs)\
$(host-cxxmulti) $(host-cxxobjs) $(host-cshlib) $(host-cshobjs)
$(host-cxxmulti) $(host-cxxobjs)
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