diff --git a/runtime/arch/x86/fault_handler_x86.cc b/runtime/arch/x86/fault_handler_x86.cc
index 8b6c9b1..89baded 100644
--- a/runtime/arch/x86/fault_handler_x86.cc
+++ b/runtime/arch/x86/fault_handler_x86.cc
@@ -28,16 +28,29 @@
 
 #if defined(__APPLE__)
 #define ucontext __darwin_ucontext
+
+#if defined(__x86_64__)
+// 64 bit mac build.
+#define CTX_ESP uc_mcontext->__ss.__rsp
+#define CTX_EIP uc_mcontext->__ss.__rip
+#define CTX_EAX uc_mcontext->__ss.__rax
+#define CTX_METHOD uc_mcontext->__ss.__rax
+#else
+// 32 bit mac build.
 #define CTX_ESP uc_mcontext->__ss.__esp
 #define CTX_EIP uc_mcontext->__ss.__eip
 #define CTX_EAX uc_mcontext->__ss.__eax
 #define CTX_METHOD uc_mcontext->__ss.__eax
+#endif
+
 #elif defined(__x86_64__)
+// 64 bit linux build.
 #define CTX_ESP uc_mcontext.gregs[REG_RSP]
 #define CTX_EIP uc_mcontext.gregs[REG_RIP]
 #define CTX_EAX uc_mcontext.gregs[REG_RAX]
 #define CTX_METHOD uc_mcontext.gregs[REG_RDI]
 #else
+// 32 bit linux build.
 #define CTX_ESP uc_mcontext.gregs[REG_ESP]
 #define CTX_EIP uc_mcontext.gregs[REG_EIP]
 #define CTX_EAX uc_mcontext.gregs[REG_EAX]
@@ -50,9 +63,18 @@
 
 namespace art {
 
+#if defined(__APPLE__) && defined(__x86_64__)
+// mac symbols have a prefix of _ on x86_64
+extern "C" void _art_quick_throw_null_pointer_exception();
+extern "C" void _art_quick_throw_stack_overflow_from_signal();
+extern "C" void _art_quick_test_suspend();
+#define EXT_SYM(sym) _ ## sym
+#else
 extern "C" void art_quick_throw_null_pointer_exception();
 extern "C" void art_quick_throw_stack_overflow_from_signal();
 extern "C" void art_quick_test_suspend();
+#define EXT_SYM(sym) sym
+#endif
 
 // Get the size of an instruction in bytes.
 // Return 0 if the instruction is not handled.
@@ -253,7 +275,7 @@
   *next_sp = retaddr;
   uc->CTX_ESP = reinterpret_cast<uintptr_t>(next_sp);
 
-  uc->CTX_EIP = reinterpret_cast<uintptr_t>(art_quick_throw_null_pointer_exception);
+  uc->CTX_EIP = reinterpret_cast<uintptr_t>(EXT_SYM(art_quick_throw_null_pointer_exception));
   VLOG(signals) << "Generating null pointer exception";
   return true;
 }
@@ -327,7 +349,7 @@
     *next_sp = retaddr;
     uc->CTX_ESP = reinterpret_cast<uintptr_t>(next_sp);
 
-    uc->CTX_EIP = reinterpret_cast<uintptr_t>(art_quick_test_suspend);
+    uc->CTX_EIP = reinterpret_cast<uintptr_t>(EXT_SYM(art_quick_test_suspend));
 
     // Now remove the suspend trigger that caused this fault.
     Thread::Current()->RemoveSuspendTrigger();
@@ -383,7 +405,7 @@
   uc->CTX_EAX = pregion;
 
   // Now arrange for the signal handler to return to art_quick_throw_stack_overflow_from_signal.
-  uc->CTX_EIP = reinterpret_cast<uintptr_t>(art_quick_throw_stack_overflow_from_signal);
+  uc->CTX_EIP = reinterpret_cast<uintptr_t>(EXT_SYM(art_quick_throw_stack_overflow_from_signal));
 
   return true;
 }
diff --git a/runtime/arch/x86_64/asm_support_x86_64.S b/runtime/arch/x86_64/asm_support_x86_64.S
index 70c71c2..682ba43 100644
--- a/runtime/arch/x86_64/asm_support_x86_64.S
+++ b/runtime/arch/x86_64/asm_support_x86_64.S
@@ -112,6 +112,8 @@
     .balign 16
 END_MACRO
 
+// TODO: we might need to use SYMBOL() here to add the underscore prefix
+// for mac builds.
 MACRO1(DEFINE_FUNCTION, c_name)
     FUNCTION_TYPE(\c_name, 0)
     .globl VAR(c_name, 0)
diff --git a/runtime/arch/x86_64/quick_entrypoints_x86_64.S b/runtime/arch/x86_64/quick_entrypoints_x86_64.S
index f021ada..cbf0f38 100644
--- a/runtime/arch/x86_64/quick_entrypoints_x86_64.S
+++ b/runtime/arch/x86_64/quick_entrypoints_x86_64.S
@@ -285,7 +285,7 @@
 NO_ARG_RUNTIME_EXCEPTION art_quick_throw_stack_overflow, artThrowStackOverflowFromCode
 
 // On entry to this function, RAX contains the ESP value for the overflow region.
-DEFINE_FUNCTION art_quick_throw_stack_overflow_from_signal
+DEFINE_FUNCTION SYMBOL(art_quick_throw_stack_overflow_from_signal)
     // Here, the RSP is above the protected region.  We need to create a
     // callee save frame and then move RSP down to the overflow region.
     SETUP_SAVE_ALL_CALLEE_SAVE_FRAME  // save all registers as basis for long jump context
@@ -294,7 +294,7 @@
     mov %gs:THREAD_SELF_OFFSET, %rdi  // pass Thread::Current() as first arg
     call PLT_SYMBOL(artThrowStackOverflowFromCode)    // artThrowStackOverflowFromCode(Thread*, SP)
     int3                              // unreached
-END_FUNCTION art_quick_throw_stack_overflow_from_signal
+END_FUNCTION SYMBOL(art_quick_throw_stack_overflow_from_signal)
 
     /*
      * Called by managed code, saves callee saves and then calls artThrowException