gcov: compile specific gcov implementation based on gcc version

commit 17c568d60af5a810208baf116dc174a2005c6c3e upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/Documentation/gcov.txt b/Documentation/gcov.txt
index e7ca647..7b72778 100644 (file)
--- a/Documentation/gcov.txt
+++ b/Documentation/gcov.txt
@@ -50,6 +50,10 @@ Configure the kernel with:
         CONFIG_DEBUG_FS=y
         CONFIG_GCOV_KERNEL=y
 
         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
 and to get coverage data for the entire kernel:
 
         CONFIG_GCOV_PROFILE_ALL=y

diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index a920281..74ae965 100644 (file)
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -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.
 
        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
 endmenu

diff --git a/kernel/gcov/Makefile b/kernel/gcov/Makefile
index e97ca59..52aa7e8 100644 (file)
--- a/kernel/gcov/Makefile
+++ b/kernel/gcov/Makefile
@@ -1,3 +1,33 @@
 ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
 
 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