Port and integrate the irregexp engine from V8

runtime/vm/parser.cc

Index: runtime/vm/parser.cc
diff --git a/runtime/vm/parser.cc b/runtime/vm/parser.cc
index 5bad57247a806ced47b690dfd19c7bf1c34accee..79711bed56e2c05cf0df15ec70147823879e9008 100644
--- a/runtime/vm/parser.cc
+++ b/runtime/vm/parser.cc
@@ -223,6 +223,24 @@ void ParsedFunction::AllocateVariables() {
 }
 
 
+void ParsedFunction::AllocateIrregexpVariables(intptr_t num_stack_locals) {
+  const intptr_t num_fixed_params = function().num_fixed_parameters();
+  const intptr_t num_opt_params = function().NumOptionalParameters();
+  const intptr_t num_params = num_fixed_params + num_opt_params;
+  // Compute start indices to parameters and locals, and the number of
+  // parameters to copy.
+  ASSERT(num_opt_params == 0);
+  // Parameter i will be at fp[kParamEndSlotFromFp + num_params - i] and
+  // local variable j will be at fp[kFirstLocalSlotFromFp - j].
+  first_parameter_index_ = kParamEndSlotFromFp + num_params;
+  first_stack_local_index_ = kFirstLocalSlotFromFp;
+  num_copied_params_ = 0;
+
+  // Frame indices are relative to the frame pointer and are decreasing.
+  num_stack_locals_ = num_stack_locals;
+}
+
+
 struct Parser::Block : public ZoneAllocated {
   Block(Block* outer_block, LocalScope* local_scope, SequenceNode* seq)
     : parent(outer_block), scope(local_scope), statements(seq) {