[Buildroot] [PATCH] valgrind: build for the right MIPS ISA revision level

[Vicente Olivert Riera]

When valgrind detects a 32-bit MIPS architecture adds -march=mips32 to
CFLAGS, and when it detects a 64-bit MIPS architecture adds
-march=mips64 instead. This causes valgrind to be built always for the
first ISA revision level (R1) which is not correct because our target
architecture could have a different ISA revision level (i.e. R2). We
need to override the CFLAGS variable and pass the right -march option.

Since R2 is backwards compatible with R1, you can run a valgrind built
for R1 in an R2 core. This is why nobody noticed about this problem, or
at least nobody complained. But, since (I hope) we will support R6 in
Buildroot in the near future, this problem will become very important
because R6 is not backwards compatible with R1 or R2, so building
valgrind for R1 when your target is R6 will result in a non-working
valgrind.

Signed-off-by: Vicente Olivert Riera <Vincent.Riera at imgtec.com>
---
 package/valgrind/valgrind.mk |   10 ++++++++++
 1 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/package/valgrind/valgrind.mk b/package/valgrind/valgrind.mk
index f8f205e..944e721 100644
--- a/package/valgrind/valgrind.mk
+++ b/package/valgrind/valgrind.mk
@@ -13,6 +13,16 @@ VALGRIND_CONF_OPTS = --disable-tls
 VALGRIND_AUTORECONF = YES
 VALGRIND_INSTALL_STAGING = YES
 
+# When valgrind detects a 32-bit MIPS architecture adds -march=mips32 to
+# CFLAGS, and when it detects a 64-bit MIPS architecture adds
+# -march=mips64 instead. This causes valgrind to be built always for the
+# first ISA revision level (R1) which is not correct because our target
+# architecture could have a different ISA revision level (i.e. R2). We
+# need to override the CFLAGS variable and pass the right -march option.
+ifeq ($(BR2_mips)$(BR2_mipsel)$(BR2_mips64)$(BR2_mips64el),y)
+VALGRIND_CONF_ENV += CFLAGS="$(TARGET_CFLAGS) -march=$(BR2_GCC_TARGET_ARCH)"
+endif
+
 # On ARM, Valgrind only supports ARMv7, and uses the arch part of the
 # host tuple to determine whether it's being built for ARMv7 or
 # not. Therefore, we adjust the host tuple to specify we're on
-- 
1.7.1