diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 1bd5ca36ded..21d0f05910a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2013-01-17  Jack Howarth <howarth@bromo.med.uc.edu>
+
+        PR sanitizer/55679
+        * g++.dg/asan/interception-test-1.C: Skip on darwin.
+        * lib/target-supports.exp (check_effective_target_swapcontext): Use
+        check_no_compiler_messages to test support in ucontext.h.
+	(check_effective_target_setrlimit): Return 0 for Darwin's non-posix
+	compliant RLIMIT_AS.
+
 2013-01-17  Marek Polacek  <polacek@redhat.com>
 
 	PR rtl-optimization/55833
diff --git a/gcc/testsuite/g++.dg/asan/interception-test-1.C b/gcc/testsuite/g++.dg/asan/interception-test-1.C
index f12f3b61e82..04c846a70a0 100644
--- a/gcc/testsuite/g++.dg/asan/interception-test-1.C
+++ b/gcc/testsuite/g++.dg/asan/interception-test-1.C
@@ -3,6 +3,7 @@
 // { dg-do run }
 // { dg-options "-fno-builtin-malloc -fno-builtin-free" }
 // { dg-shouldfail "asan" }
+// { dg-skip-if "Darwin uses mac function interposition" { *-*-darwin* } }
 
 #include <stdlib.h>
 #include <stdio.h>
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index abc90384d5f..0b11817ff61 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -730,12 +730,23 @@ proc check_effective_target_clone {} {
 
 # Return 1 if the target supports setrlimit, 0 otherwise.
 proc check_effective_target_setrlimit {} {
+    # Darwin has non-posix compliant RLIMIT_AS
+    if { [istarget *-*-darwin*] } {
+        return 0
+    }
     return [check_function_available "setrlimit"]
 }
 
 # Return 1 if the target supports swapcontext, 0 otherwise.
 proc check_effective_target_swapcontext {} {
-    return [check_function_available "swapcontext"]
+    return [check_no_compiler_messages swapcontext executable {
+	#include <ucontext.h>
+	int main (void)
+	{
+	  ucontext_t orig_context,child_context;
+	  if (swapcontext(&child_context, &orig_context) < 0) { }
+	}
+    }]
 }
 
 # Return 1 if compilation with -pthread is error-free for trivial