linux/scripts/Makefile.lib
Peter Oberparleiter 2521f2c228 gcov: add gcov profiling infrastructure
Enable the use of GCC's coverage testing tool gcov [1] with the Linux
kernel.  gcov may be useful for:

 * debugging (has this code been reached at all?)
 * test improvement (how do I change my test to cover these lines?)
 * minimizing kernel configurations (do I need this option if the
   associated code is never run?)

The profiling patch incorporates the following changes:

 * change kbuild to include profiling flags
 * provide functions needed by profiling code
 * present profiling data as files in debugfs

Note that on some architectures, enabling gcc's profiling option
"-fprofile-arcs" for the entire kernel may trigger compile/link/
run-time problems, some of which are caused by toolchain bugs and
others which require adjustment of architecture code.

For this reason profiling the entire kernel is initially restricted
to those architectures for which it is known to work without changes.
This restriction can be lifted once an architecture has been tested
and found compatible with gcc's profiling. Profiling of single files
or directories is still available on all platforms (see config help
text).

[1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html

Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Li Wei <W.Li@Sun.COM>
Cc: Michael Ellerman <michaele@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Heiko Carstens <heicars2@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <mschwid2@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-18 13:03:57 -07:00

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# Backward compatibility
asflags-y += $(EXTRA_AFLAGS)
ccflags-y += $(EXTRA_CFLAGS)
cppflags-y += $(EXTRA_CPPFLAGS)
ldflags-y += $(EXTRA_LDFLAGS)
#
# flags that take effect in sub directories
export KBUILD_SUBDIR_ASFLAGS := $(KBUILD_SUBDIR_ASFLAGS) $(subdir-asflags-y)
export KBUILD_SUBDIR_CCFLAGS := $(KBUILD_SUBDIR_CCFLAGS) $(subdir-ccflags-y)
# Figure out what we need to build from the various variables
# ===========================================================================
# When an object is listed to be built compiled-in and modular,
# only build the compiled-in version
obj-m := $(filter-out $(obj-y),$(obj-m))
# Libraries are always collected in one lib file.
# Filter out objects already built-in
lib-y := $(filter-out $(obj-y), $(sort $(lib-y) $(lib-m)))
# Handle objects in subdirs
# ---------------------------------------------------------------------------
# o if we encounter foo/ in $(obj-y), replace it by foo/built-in.o
# and add the directory to the list of dirs to descend into: $(subdir-y)
# o if we encounter foo/ in $(obj-m), remove it from $(obj-m)
# and add the directory to the list of dirs to descend into: $(subdir-m)
# Determine modorder.
# Unfortunately, we don't have information about ordering between -y
# and -m subdirs. Just put -y's first.
modorder := $(patsubst %/,%/modules.order, $(filter %/, $(obj-y)) $(obj-m:.o=.ko))
__subdir-y := $(patsubst %/,%,$(filter %/, $(obj-y)))
subdir-y += $(__subdir-y)
__subdir-m := $(patsubst %/,%,$(filter %/, $(obj-m)))
subdir-m += $(__subdir-m)
obj-y := $(patsubst %/, %/built-in.o, $(obj-y))
obj-m := $(filter-out %/, $(obj-m))
# Subdirectories we need to descend into
subdir-ym := $(sort $(subdir-y) $(subdir-m))
# if $(foo-objs) exists, foo.o is a composite object
multi-used-y := $(sort $(foreach m,$(obj-y), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
multi-used-m := $(sort $(foreach m,$(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))), $(m))))
multi-used := $(multi-used-y) $(multi-used-m)
single-used-m := $(sort $(filter-out $(multi-used-m),$(obj-m)))
# Build list of the parts of our composite objects, our composite
# objects depend on those (obviously)
multi-objs-y := $(foreach m, $(multi-used-y), $($(m:.o=-objs)) $($(m:.o=-y)))
multi-objs-m := $(foreach m, $(multi-used-m), $($(m:.o=-objs)) $($(m:.o=-y)))
multi-objs := $(multi-objs-y) $(multi-objs-m)
# $(subdir-obj-y) is the list of objects in $(obj-y) which uses dir/ to
# tell kbuild to descend
subdir-obj-y := $(filter %/built-in.o, $(obj-y))
# $(obj-dirs) is a list of directories that contain object files
obj-dirs := $(dir $(multi-objs) $(subdir-obj-y))
# Replace multi-part objects by their individual parts, look at local dir only
real-objs-y := $(foreach m, $(filter-out $(subdir-obj-y), $(obj-y)), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m))) $(extra-y)
real-objs-m := $(foreach m, $(obj-m), $(if $(strip $($(m:.o=-objs)) $($(m:.o=-y))),$($(m:.o=-objs)) $($(m:.o=-y)),$(m)))
# Add subdir path
extra-y := $(addprefix $(obj)/,$(extra-y))
always := $(addprefix $(obj)/,$(always))
targets := $(addprefix $(obj)/,$(targets))
modorder := $(addprefix $(obj)/,$(modorder))
obj-y := $(addprefix $(obj)/,$(obj-y))
obj-m := $(addprefix $(obj)/,$(obj-m))
lib-y := $(addprefix $(obj)/,$(lib-y))
subdir-obj-y := $(addprefix $(obj)/,$(subdir-obj-y))
real-objs-y := $(addprefix $(obj)/,$(real-objs-y))
real-objs-m := $(addprefix $(obj)/,$(real-objs-m))
single-used-m := $(addprefix $(obj)/,$(single-used-m))
multi-used-y := $(addprefix $(obj)/,$(multi-used-y))
multi-used-m := $(addprefix $(obj)/,$(multi-used-m))
multi-objs-y := $(addprefix $(obj)/,$(multi-objs-y))
multi-objs-m := $(addprefix $(obj)/,$(multi-objs-m))
subdir-ym := $(addprefix $(obj)/,$(subdir-ym))
obj-dirs := $(addprefix $(obj)/,$(obj-dirs))
# These flags are needed for modversions and compiling, so we define them here
# already
# $(modname_flags) #defines KBUILD_MODNAME as the name of the module it will
# end up in (or would, if it gets compiled in)
# Note: It's possible that one object gets potentially linked into more
# than one module. In that case KBUILD_MODNAME will be set to foo_bar,
# where foo and bar are the name of the modules.
name-fix = $(subst $(comma),_,$(subst -,_,$1))
basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))"
modname_flags = $(if $(filter 1,$(words $(modname))),\
-D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")
#hash values
ifdef CONFIG_DYNAMIC_DEBUG
debug_flags = -D"DEBUG_HASH=$(shell ./scripts/basic/hash djb2 $(@D)$(modname))"\
-D"DEBUG_HASH2=$(shell ./scripts/basic/hash r5 $(@D)$(modname))"
else
debug_flags =
endif
orig_c_flags = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \
$(ccflags-y) $(CFLAGS_$(basetarget).o)
_c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
_a_flags = $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(KBUILD_SUBDIR_ASFLAGS) \
$(asflags-y) $(AFLAGS_$(basetarget).o)
_cpp_flags = $(KBUILD_CPPFLAGS) $(cppflags-y) $(CPPFLAGS_$(@F))
#
# Enable gcov profiling flags for a file, directory or for all files depending
# on variables GCOV_PROFILE_obj.o, GCOV_PROFILE and CONFIG_GCOV_PROFILE_ALL
# (in this order)
#
ifeq ($(CONFIG_GCOV_KERNEL),y)
_c_flags += $(if $(patsubst n%,, \
$(GCOV_PROFILE_$(basetarget).o)$(GCOV_PROFILE)$(CONFIG_GCOV_PROFILE_ALL)), \
$(CFLAGS_GCOV))
endif
# If building the kernel in a separate objtree expand all occurrences
# of -Idir to -I$(srctree)/dir except for absolute paths (starting with '/').
ifeq ($(KBUILD_SRC),)
__c_flags = $(_c_flags)
__a_flags = $(_a_flags)
__cpp_flags = $(_cpp_flags)
else
# -I$(obj) locates generated .h files
# $(call addtree,-I$(obj)) locates .h files in srctree, from generated .c files
# and locates generated .h files
# FIXME: Replace both with specific CFLAGS* statements in the makefiles
__c_flags = $(call addtree,-I$(obj)) $(call flags,_c_flags)
__a_flags = $(call flags,_a_flags)
__cpp_flags = $(call flags,_cpp_flags)
endif
c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(__c_flags) $(modkern_cflags) \
-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags) \
$(debug_flags)
a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(__a_flags) $(modkern_aflags)
cpp_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
$(__cpp_flags)
ld_flags = $(LDFLAGS) $(ldflags-y)
# Finds the multi-part object the current object will be linked into
modname-multi = $(sort $(foreach m,$(multi-used),\
$(if $(filter $(subst $(obj)/,,$*.o), $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))
# Shipped files
# ===========================================================================
quiet_cmd_shipped = SHIPPED $@
cmd_shipped = cat $< > $@
$(obj)/%:: $(src)/%_shipped
$(call cmd,shipped)
# Commands useful for building a boot image
# ===========================================================================
#
# Use as following:
#
# target: source(s) FORCE
# $(if_changed,ld/objcopy/gzip)
#
# and add target to extra-y so that we know we have to
# read in the saved command line
# Linking
# ---------------------------------------------------------------------------
quiet_cmd_ld = LD $@
cmd_ld = $(LD) $(LDFLAGS) $(ldflags-y) $(LDFLAGS_$(@F)) \
$(filter-out FORCE,$^) -o $@
# Objcopy
# ---------------------------------------------------------------------------
quiet_cmd_objcopy = OBJCOPY $@
cmd_objcopy = $(OBJCOPY) $(OBJCOPYFLAGS) $(OBJCOPYFLAGS_$(@F)) $< $@
# Gzip
# ---------------------------------------------------------------------------
quiet_cmd_gzip = GZIP $@
cmd_gzip = (cat $(filter-out FORCE,$^) | gzip -f -9 > $@) || \
(rm -f $@ ; false)
# Bzip2
# ---------------------------------------------------------------------------
# Bzip2 and LZMA do not include size in file... so we have to fake that;
# append the size as a 32-bit littleendian number as gzip does.
size_append = echo -ne $(shell \
dec_size=0; \
for F in $1; do \
fsize=$$(stat -c "%s" $$F); \
dec_size=$$(expr $$dec_size + $$fsize); \
done; \
printf "%08x" $$dec_size | \
sed 's/\(..\)\(..\)\(..\)\(..\)/\\\\x\4\\\\x\3\\\\x\2\\\\x\1/g' \
)
quiet_cmd_bzip2 = BZIP2 $@
cmd_bzip2 = (cat $(filter-out FORCE,$^) | \
bzip2 -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
(rm -f $@ ; false)
# Lzma
# ---------------------------------------------------------------------------
quiet_cmd_lzma = LZMA $@
cmd_lzma = (cat $(filter-out FORCE,$^) | \
lzma -9 && $(call size_append, $(filter-out FORCE,$^))) > $@ || \
(rm -f $@ ; false)