Inserted a missing string encoding check in lastIndexOf.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index f629970ff28209a568124a23ef07bed9194cbe3c..46f314e48b5e38dc0caf01c90d34d65b3e1b7f67 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -3163,25 +3163,31 @@ RUNTIME_FUNCTION(MaybeObject*, Runtime_StringLastIndexOf) {
 
   int position = -1;
 
-  if (pat->IsAsciiRepresentation()) {
-    Vector<const char> pat_vector = pat->ToAsciiVector();
-    if (sub->IsAsciiRepresentation()) {
-      position = StringMatchBackwards(sub->ToAsciiVector(),
+  String* seq_sub = *sub;
+  // Extract flattened substrings of cons strings before determining asciiness.

[Vitaly Repeshko, 2011/08/22 13:37:46]

nit: Move the comment one line above.

+  if (seq_sub->IsConsString()) seq_sub = ConsString::cast(seq_sub)->first();
+  String* seq_pat = *pat;
+  if (seq_pat->IsConsString()) seq_pat = ConsString::cast(seq_pat)->first();
+
+  if (seq_pat->IsAsciiRepresentation()) {
+    Vector<const char> pat_vector = seq_pat->ToAsciiVector();
+    if (seq_sub->IsAsciiRepresentation()) {
+      position = StringMatchBackwards(seq_sub->ToAsciiVector(),
                                       pat_vector,
                                       start_index);
     } else {
-      position = StringMatchBackwards(sub->ToUC16Vector(),
+      position = StringMatchBackwards(seq_sub->ToUC16Vector(),
                                       pat_vector,
                                       start_index);
     }
   } else {
-    Vector<const uc16> pat_vector = pat->ToUC16Vector();
-    if (sub->IsAsciiRepresentation()) {
-      position = StringMatchBackwards(sub->ToAsciiVector(),
+    Vector<const uc16> pat_vector = seq_pat->ToUC16Vector();
+    if (seq_sub->IsAsciiRepresentation()) {
+      position = StringMatchBackwards(seq_sub->ToAsciiVector(),
                                       pat_vector,
                                       start_index);
     } else {
-      position = StringMatchBackwards(sub->ToUC16Vector(),
+      position = StringMatchBackwards(seq_sub->ToUC16Vector(),
                                       pat_vector,
                                       start_index);
     }