Add checks to runtime functions.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 5e306dda57dc5b694281d2240174e522744f4958..78e1dec51358f5aa40ff2854ffdd989452d0608f 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -3036,19 +3036,18 @@ void FullCodeGenerator::EmitDateField(CallRuntime* expr) {
 
   VisitForAccumulatorValue(args->at(0));  // Load the object.
 
-  Label runtime, done;
+  Label runtime, done, not_date_object;
   Register object = rax;
   Register result = rax;
   Register scratch = rcx;
 
-#ifdef DEBUG
-  __ AbortIfSmi(object);
+  __ JumpIfSmi(object, &not_date_object);
   __ CmpObjectType(object, JS_DATE_TYPE, scratch);
-  __ Assert(equal, "Trying to get date field from non-date.");
-#endif
+  __ j(not_equal, &not_date_object);
 
   if (index->value() == 0) {
     __ movq(result, FieldOperand(object, JSDate::kValueOffset));
+    __ jmp(&done);
   } else {
     if (index->value() < JSDate::kFirstUncachedField) {
       ExternalReference stamp = ExternalReference::date_cache_stamp(isolate());
@@ -3070,8 +3069,12 @@ void FullCodeGenerator::EmitDateField(CallRuntime* expr) {
 #endif
     __ CallCFunction(ExternalReference::get_date_field_function(isolate()), 2);
     __ movq(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
-    __ bind(&done);
+    __ jmp(&done);
   }
+
+  __ bind(&not_date_object);
+  __ CallRuntime(Runtime::kThrowNotDateError, 0);
+  __ bind(&done);
   context()->Plug(rax);
 }
 
@@ -3495,9 +3498,7 @@ void FullCodeGenerator::EmitGetCachedArrayIndex(CallRuntime* expr) {
   ASSERT(args->length() == 1);
   VisitForAccumulatorValue(args->at(0));
 
-  if (generate_debug_code_) {
-    __ AbortIfNotString(rax);
-  }
+  __ AbortIfNotString(rax);
 
   __ movl(rax, FieldOperand(rax, String::kHashFieldOffset));
   ASSERT(String::kHashShift >= kSmiTagSize);