Move StringMatch to String::IndexOf

src/objects.cc

Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index 3068b85cdeb6c913b1c6d1e92bdc4d6073509ee5..503354cd373fcb69e04ee01637df8d374e241191 100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -11207,6 +11207,42 @@ ComparisonResult String::Compare(Handle<String> x, Handle<String> y) {
   return result;
 }
 
+int String::IndexOf(Isolate* isolate, Handle<String> sub, Handle<String> pat,
+                    int start_index) {
+  DCHECK(0 <= start_index);
+  DCHECK(start_index <= sub->length());
+
+  int pattern_length = pat->length();
+  if (pattern_length == 0) return start_index;
+
+  int subject_length = sub->length();
+  if (start_index + pattern_length > subject_length) return -1;
+
+  sub = String::Flatten(sub);
+  pat = String::Flatten(pat);
+
+  DisallowHeapAllocation no_gc;  // ensure vectors stay valid
+  // Extract flattened substrings of cons strings before getting encoding.
+  String::FlatContent seq_sub = sub->GetFlatContent();
+  String::FlatContent seq_pat = pat->GetFlatContent();
+
+  // dispatch on type of strings
+  if (seq_pat.IsOneByte()) {
+    Vector<const uint8_t> pat_vector = seq_pat.ToOneByteVector();
+    if (seq_sub.IsOneByte()) {
+      return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
+                          start_index);
+    }
+    return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector,
+                        start_index);
+  }
+  Vector<const uc16> pat_vector = seq_pat.ToUC16Vector();
+  if (seq_sub.IsOneByte()) {
+    return SearchString(isolate, seq_sub.ToOneByteVector(), pat_vector,
+                        start_index);
+  }
+  return SearchString(isolate, seq_sub.ToUC16Vector(), pat_vector, start_index);
+}
 
 bool String::IsUtf8EqualTo(Vector<const char> str, bool allow_prefix_match) {
   int slen = length();