VM: Optimize RegExp.matchAsPrefix(...) by generating a sticky RegExp specialization.

runtime/lib/regexp.cc

Index: runtime/lib/regexp.cc
diff --git a/runtime/lib/regexp.cc b/runtime/lib/regexp.cc
index 7a50561109244c8f55282b3aedc2d02edff0e1f0..87795731c57db2a2461f537c3fa7cacf6ea594dc 100644
--- a/runtime/lib/regexp.cc
+++ b/runtime/lib/regexp.cc
@@ -78,19 +78,34 @@ DEFINE_NATIVE_ENTRY(RegExp_getGroupCount, 1) {
 }
 
 
-DEFINE_NATIVE_ENTRY(RegExp_ExecuteMatch, 3) {
-  // This function is intrinsified. See Intrinsifier::RegExp_ExecuteMatch.
+static RawObject* ExecuteMatch(Zone* zone,
+                               NativeArguments* arguments,
+                               bool sticky) {
   const RegExp& regexp = RegExp::CheckedHandle(arguments->NativeArgAt(0));
   ASSERT(!regexp.IsNull());
   GET_NON_NULL_NATIVE_ARGUMENT(String, subject, arguments->NativeArgAt(1));
   GET_NON_NULL_NATIVE_ARGUMENT(Smi, start_index, arguments->NativeArgAt(2));
 
-  if (FLAG_interpret_irregexp || FLAG_precompiled_runtime) {
+  if (FLAG_interpret_irregexp) {
     return BytecodeRegExpMacroAssembler::Interpret(regexp, subject, start_index,
-                                                   zone);
+                                                   /*sticky=*/sticky, zone);
   }
 
-  return IRRegExpMacroAssembler::Execute(regexp, subject, start_index, zone);
+  return IRRegExpMacroAssembler::Execute(regexp, subject, start_index,
+                                         /*sticky=*/sticky, zone);
 }
 
+
+DEFINE_NATIVE_ENTRY(RegExp_ExecuteMatch, 3) {
+  // This function is intrinsified. See Intrinsifier::RegExp_ExecuteMatch.
+  return ExecuteMatch(zone, arguments, /*sticky=*/false);
+}
+
+
+DEFINE_NATIVE_ENTRY(RegExp_ExecuteMatchSticky, 3) {
+  // This function is intrinsified. See Intrinsifier::RegExp_ExecuteMatchSticky.
+  return ExecuteMatch(zone, arguments, /*sticky=*/true);
+}
+
+
 }  // namespace dart