gcc: xtensa: enable address sanitizer

gcc/
2017-12-05  Max Filippov  <jcmvbkbc@gmail.com>

	* config/xtensa/xtensa.c (xtensa_asan_shadow_offset): New
	function.
	(TARGET_ASAN_SHADOW_OFFSET): New macro definition.
	* config/xtensa/xtensa.h (FRAME_GROWS_DOWNWARD): Set to 1 if
	ASAN is enabled.

From-SVN: r255420

gcc/ChangeLog

+2017-12-05  Max Filippov  <jcmvbkbc@gmail.com>
+
+	* config/xtensa/xtensa.c (xtensa_asan_shadow_offset): New
+	function.
+	(TARGET_ASAN_SHADOW_OFFSET): New macro definition.
+	* config/xtensa/xtensa.h (FRAME_GROWS_DOWNWARD): Set to 1 if
+	ASAN is enabled.
+
 2017-12-05  Richard Biener   <rguenther@suse.de>
 
 	* timevar.def (TV_TREE_RECIP, TV_TREE_SINCOS, TV_TREE_WIDEN_MUL):

gcc/config/xtensa/xtensa.c

@@ -183,6 +183,7 @@ static bool xtensa_hard_regno_mode_ok (unsigned int, machine_mode);
 static bool xtensa_modes_tieable_p (machine_mode, machine_mode);
 static HOST_WIDE_INT xtensa_constant_alignment (const_tree, HOST_WIDE_INT);
 static HOST_WIDE_INT xtensa_starting_frame_offset (void);
+static unsigned HOST_WIDE_INT xtensa_asan_shadow_offset (void);
 
 
 
@@ -325,6 +326,9 @@ static HOST_WIDE_INT xtensa_starting_frame_offset (void);
 #undef TARGET_STARTING_FRAME_OFFSET
 #define TARGET_STARTING_FRAME_OFFSET xtensa_starting_frame_offset
 
+#undef TARGET_ASAN_SHADOW_OFFSET
+#define TARGET_ASAN_SHADOW_OFFSET xtensa_asan_shadow_offset
+
 struct gcc_target targetm = TARGET_INITIALIZER;
 
 
@@ -4413,4 +4417,12 @@ xtensa_starting_frame_offset (void)
   return crtl->outgoing_args_size;
 }
 
+/* Implement TARGET_ASAN_SHADOW_OFFSET.  */
+
+static unsigned HOST_WIDE_INT
+xtensa_asan_shadow_offset (void)
+{
+  return HOST_WIDE_INT_UC (0x10000000);
+}
+
 #include "gt-xtensa.h"

gcc/config/xtensa/xtensa.h

@@ -430,7 +430,8 @@ enum reg_class
 
 #define STACK_GROWS_DOWNWARD 1
 
-#define FRAME_GROWS_DOWNWARD flag_stack_protect
+#define FRAME_GROWS_DOWNWARD (flag_stack_protect \
+			      || (flag_sanitize & SANITIZE_ADDRESS) != 0)
 
 /* The ARG_POINTER and FRAME_POINTER are not real Xtensa registers, so
    they are eliminated to either the stack pointer or hard frame pointer.  */