arm-common.c (arm_except_unwind_info): Handle DWARF2_UNWIND_INFO.

2017-10-08  Olivier Hainque  <hainque@adacore.com>

        * common/config/arm/arm-common.c (arm_except_unwind_info):
        Handle DWARF2_UNWIND_INFO.

From-SVN: r253521

gcc/ChangeLog

+2017-10-08  Olivier Hainque  <hainque@adacore.com>
+
+	* common/config/arm/arm-common.c (arm_except_unwind_info):
+	Handle DWARF2_UNWIND_INFO.
+
 2017-10-07  Michael Collison <michael.collison@arm.com>
 
 	* config/aarch64/aarch64.md (*aarch64_reg_<optab>_minus<mode>3):

gcc/common/config/arm/arm-common.c

@@ -63,7 +63,13 @@ arm_except_unwind_info (struct gcc_options *opts)
 	return UI_TARGET;
     }
 
-  /* ... we use sjlj exceptions for backwards compatibility.  */
+  /* ... honor target configurations requesting DWARF2 EH...  */
+#ifdef DWARF2_UNWIND_INFO
+  if (DWARF2_UNWIND_INFO)
+    return UI_DWARF2;
+#endif
+
+  /* ... or fallback to sjlj exceptions for backwards compatibility.  */
   return UI_SJLJ;
 }