gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT

CONFIG_GCOV_FORMAT_AUTODETECT compiles either gcc_3_4.c or gcc_4_7.c
according to your GCC version.

We can achieve the equivalent behavior by setting reasonable dependency
with the knowledge of the compiler version.

If GCC older than 4.7 is used, GCOV_FORMAT_3_4 is the default, but users
are still allowed to select GCOV_FORMAT_4_7 in case the newer format is
back-ported.

On the other hand, If GCC 4.7 or newer is used, there is no reason to
use GCOV_FORMAT_3_4, so it should be hidden.

If you downgrade the compiler to GCC 4.7 or older, oldconfig/syncconfig
will display a prompt for the choice because GCOV_FORMAT_3_4 becomes
visible as a new symbol.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>

2 files changed, 5 insertions, 14 deletions

diff --git a/kernel/gcov/Kconfig b/kernel/gcov/Kconfig
index 1276aabaab55..1e3823fa799b 100644
--- a/kernel/gcov/Kconfig
+++ b/kernel/gcov/Kconfig
@@ -53,23 +53,16 @@ config GCOV_PROFILE_ALL
 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
+        The gcov format is usually determined by the GCC version, and the
+        default is chosen according to your GCC version. However, 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.
+        In such a case, change this option to adjust the format used in the
+        kernel accordingly.
 
 config GCOV_FORMAT_3_4
         bool "GCC 3.4 format"
+        depends on CC_IS_GCC && GCC_VERSION < 40700
         ---help---
         Select this option to use the format defined by GCC 3.4.
 
diff --git a/kernel/gcov/Makefile b/kernel/gcov/Makefile
index c6c50e5c680e..ff06d64df397 100644
--- a/kernel/gcov/Makefile
+++ b/kernel/gcov/Makefile
@@ -4,5 +4,3 @@ ccflags-y := -DSRCTREE='"$(srctree)"' -DOBJTREE='"$(objtree)"'
 obj-y := base.o fs.o
 obj-$(CONFIG_GCOV_FORMAT_3_4) += gcc_3_4.o
 obj-$(CONFIG_GCOV_FORMAT_4_7) += gcc_4_7.o
-obj-$(CONFIG_GCOV_FORMAT_AUTODETECT) += $(call cc-ifversion, -lt, 0407, \
-                                                        gcc_3_4.o, gcc_4_7.o)