Port and integrate the irregexp engine from V8

runtime/vm/parser.h

Index: runtime/vm/parser.h
diff --git a/runtime/vm/parser.h b/runtime/vm/parser.h
index d249655e9947fd59f05c10031ed9d09a4c967015..4ccb61568dbd9c967f7af0ac790bf7d9df02c34a 100644
--- a/runtime/vm/parser.h
+++ b/runtime/vm/parser.h
@@ -142,6 +142,10 @@ class ParsedFunction : public ZoneAllocated {
 
   void AllocateVariables();
 
+  // TODO(jgruber): Refactor this, mostly copied from AllocateVariables.
+  // Sets variables required for reserving enough space for local variables.
+  void AllocateIrregexpVariables(intptr_t num_stack_locals);

[Florian Schneider, 2014/09/16 11:11:48]

Why does AllocateVariables not work?

[jgruber1, 2014/09/22 18:58:04]

AllocateVariables calculates the number of locals, while it is passed into
AllocateIrregexpVariables as an argument (ultimately it is taken from the regexp
macro assembler after compilation to Dart IR). 

The logic of the function itself is short enough that it seemed like a better
choice to create a specialized version just for irregexps.

+
   void set_await_temps_scope(LocalScope* scope) {
     ASSERT(await_temps_scope_ == NULL);
     await_temps_scope_ = scope;