gcov: compile specific gcov implementation based on gcc version

Compile the correct gcov implementation file for the specific gcc version.

Signed-off-by: Frantisek Hrbata <fhrbata@redhat.com>
Cc: Jan Stancek <jstancek@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andy Gospodarek <agospoda@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Frantisek Hrbata 2013-11-12 15:11:27 -08:00 committed by Linus Torvalds
parent 5f41ea0386
commit 17c568d60a
3 changed files with 65 additions and 1 deletions

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@ -50,6 +50,10 @@ Configure the kernel with:
CONFIG_DEBUG_FS=y
CONFIG_GCOV_KERNEL=y
select the gcc's gcov format, default is autodetect based on gcc version:
CONFIG_GCOV_FORMAT_AUTODETECT=y
and to get coverage data for the entire kernel:
CONFIG_GCOV_PROFILE_ALL=y

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@ -46,4 +46,34 @@ config GCOV_PROFILE_ALL
larger and run slower. Also be sure to exclude files from profiling
which are not linked to the kernel image to prevent linker errors.
choice
prompt "Specify GCOV format"
depends on GCOV_KERNEL
default GCOV_FORMAT_AUTODETECT
---help---
The gcov format is usually determined by the GCC version, but there are
exceptions where format changes are integrated in lower-version GCCs.
In such a case use this option to adjust the format used in the kernel
accordingly.
If unsure, choose "Autodetect".
config GCOV_FORMAT_AUTODETECT
bool "Autodetect"
---help---
Select this option to use the format that corresponds to your GCC
version.
config GCOV_FORMAT_3_4
bool "GCC 3.4 format"
---help---
Select this option to use the format defined by GCC 3.4.
config GCOV_FORMAT_4_7
bool "GCC 4.7 format"
---help---
Select this option to use the format defined by GCC 4.7.
endchoice
endmenu

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@ -1,3 +1,33 @@
ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
obj-$(CONFIG_GCOV_KERNEL) := base.o fs.o gcc_3_4.o
# if-lt
# Usage VAR := $(call if-lt, $(a), $(b))
# Returns 1 if (a < b)
if-lt = $(shell [ $(1) -lt $(2) ] && echo 1)
ifeq ($(CONFIG_GCOV_FORMAT_3_4),y)
cc-ver := 0304
else ifeq ($(CONFIG_GCOV_FORMAT_4_7),y)
cc-ver := 0407
else
# Use cc-version if available, otherwise set 0
#
# scripts/Kbuild.include, which contains cc-version function, is not included
# during make clean "make -f scripts/Makefile.clean obj=kernel/gcov"
# Meaning cc-ver is empty causing if-lt test to fail with
# "/bin/sh: line 0: [: -lt: unary operator expected" error mesage.
# This has no affect on the clean phase, but the error message could be
# confusing/annoying. So this dummy workaround sets cc-ver to zero if cc-version
# is not available. We can probably move if-lt to Kbuild.include, so it's also
# not defined during clean or to include Kbuild.include in
# scripts/Makefile.clean. But the following workaround seems least invasive.
cc-ver := $(if $(call cc-version),$(call cc-version),0)
endif
obj-$(CONFIG_GCOV_KERNEL) := base.o fs.o
ifeq ($(call if-lt, $(cc-ver), 0407),1)
obj-$(CONFIG_GCOV_KERNEL) += gcc_3_4.o
else
obj-$(CONFIG_GCOV_KERNEL) += gcc_4_7.o
endif