[Qemu-devel] [PATCH 4/5] tcg-arm: Simplify logic in detecting the ARM ISA in use

[Richard Henderson <rth@twiddle.net>]

GCC 4.8 defines a handy __ARM_ARCH symbol that we can use, which
will make us nicely forward compatible with ARMv8 AArch32.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 tcg/arm/tcg-target.c | 62 +++++++++++++++++-----------------------------------
 1 file changed, 20 insertions(+), 42 deletions(-)

diff --git a/tcg/arm/tcg-target.c b/tcg/arm/tcg-target.c
index f6bc165..202f1fc 100644
--- a/tcg/arm/tcg-target.c
+++ b/tcg/arm/tcg-target.c
@@ -22,50 +22,28 @@
  * THE SOFTWARE.
  */
 
-#if defined(__ARM_ARCH_7__) ||  \
-    defined(__ARM_ARCH_7A__) || \
-    defined(__ARM_ARCH_7EM__) || \
-    defined(__ARM_ARCH_7M__) || \
-    defined(__ARM_ARCH_7R__)
-#define USE_ARMV7_INSTRUCTIONS
+/* The __ARM_ARCH define is provided by gcc 4.8.  Construct it otherwise.  */
+#ifndef __ARM_ARCH
+# if defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) \
+     || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) \
+     || defined(__ARM_ARCH_7EM__)
+#  define __ARM_ARCH 7
+# elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) \
+       || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__) \
+       || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6T2__)
+#  define __ARM_ARCH 6
+# elif defined(__ARM_ARCH_5__) || defined(__ARM_ARCH_5E__) \
+       || defined(__ARM_ARCH_5T__) || defined(__ARM_ARCH_5TE__) \
+       || defined(__ARM_ARCH_5TEJ__)
+#  define __ARM_ARCH 5
+# else
+#  define __ARM_ARCH 4
+# endif
 #endif
 
-#if defined(USE_ARMV7_INSTRUCTIONS) || \
-    defined(__ARM_ARCH_6J__) || \
-    defined(__ARM_ARCH_6K__) || \
-    defined(__ARM_ARCH_6T2__) || \
-    defined(__ARM_ARCH_6Z__) || \
-    defined(__ARM_ARCH_6ZK__)
-#define USE_ARMV6_INSTRUCTIONS
-#endif
-
-#if defined(USE_ARMV6_INSTRUCTIONS) || \
-    defined(__ARM_ARCH_5T__) || \
-    defined(__ARM_ARCH_5TE__) || \
-    defined(__ARM_ARCH_5TEJ__)
-#define USE_ARMV5_INSTRUCTIONS
-#endif
-
-#ifdef USE_ARMV5_INSTRUCTIONS
-static const int use_armv5_instructions = 1;
-#else
-static const int use_armv5_instructions = 0;
-#endif
-#undef USE_ARMV5_INSTRUCTIONS
-
-#ifdef USE_ARMV6_INSTRUCTIONS
-static const int use_armv6_instructions = 1;
-#else
-static const int use_armv6_instructions = 0;
-#endif
-#undef USE_ARMV6_INSTRUCTIONS
-
-#ifdef USE_ARMV7_INSTRUCTIONS
-static const int use_armv7_instructions = 1;
-#else
-static const int use_armv7_instructions = 0;
-#endif
-#undef USE_ARMV7_INSTRUCTIONS
+#define use_armv5_instructions  (__ARM_ARCH >= 5)
+#define use_armv6_instructions  (__ARM_ARCH >= 6)
+#define use_armv7_instructions  (__ARM_ARCH >= 7)
 
 #ifndef use_idiv_instructions
 bool use_idiv_instructions;
-- 
1.8.1.4