[PATCH] perf tools: Makefile: Use gcc to determine ARCH

[Lin Ming <ming.m.lin@intel.com>]

The original Makefile uses "uname -m" to determine ARCH.
This causes problem on x86 when compile perf tool on 32 bit userspace
with a 64 bit kernel.

bench/../../../arch/x86/lib/memcpy_64.S: Assembler messages:
bench/../../../arch/x86/lib/memcpy_64.S:28: Error: bad register name `%rdi'

This is because "uname -m" returns x86_64 and memcpy_64.S is included in 32 bit build.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
---
 tools/perf/Makefile |   16 ++++++++++------
 1 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 91ad5cc..1455413 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -43,15 +43,21 @@ ARCH ?= $(shell echo $(uname_M) | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
 				  -e s/ppc.*/powerpc/ -e s/mips.*/mips/ \
 				  -e s/sh[234].*/sh/ )
 
+CC = $(CROSS_COMPILE)gcc
+AR = $(CROSS_COMPILE)ar
+
 # Additional ARCH settings for x86
 ifeq ($(ARCH),i386)
         ARCH := x86
 endif
 ifeq ($(ARCH),x86_64)
-	RAW_ARCH := x86_64
-        ARCH := x86
-	ARCH_CFLAGS := -DARCH_X86_64
-	ARCH_INCLUDE = ../../arch/x86/lib/memcpy_64.S
+	ARCH := x86
+	IS_X86_64 := $(shell echo __x86_64__ | ${CC} -E -xc - | tail -n 1)
+	ifeq (${IS_X86_64}, 1)
+		RAW_ARCH := x86_64
+		ARCH_CFLAGS := -DARCH_X86_64
+		ARCH_INCLUDE = ../../arch/x86/lib/memcpy_64.S
+	endif
 endif
 
 #
@@ -127,8 +133,6 @@ lib = lib
 
 export prefix bindir sharedir sysconfdir
 
-CC = $(CROSS_COMPILE)gcc
-AR = $(CROSS_COMPILE)ar
 RM = rm -f
 MKDIR = mkdir
 FIND = find
-- 
1.7.4.4