Limit work done analyzing regexps with very large fanout.

src/jsregexp.h

Index: src/jsregexp.h
===================================================================
--- src/jsregexp.h	(revision 11692)
+++ src/jsregexp.h	(working copy)
@@ -581,8 +581,10 @@
   // we look forward.  This is used for a Boyer-Moore-like string searching
   // implementation.  TODO(erikcorry):  This should share more code with
   // EatsAtLeast, GetQuickCheckDetails.
+  static const int kFillInBMBudget = 200;
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,

[ulan, 2012/06/01 11:24:04]

Please add a description for budget.

                             BoyerMooreLookahead* bm,
                             bool not_at_start) {
     UNREACHABLE();
@@ -685,9 +687,11 @@
   virtual RegExpNode* FilterASCII(int depth);
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start) {
-    on_success_->FillInBMInfo(offset, recursion_depth + 1, bm, not_at_start);
+    on_success_->FillInBMInfo(
+        offset, recursion_depth + 1, budget - 1, bm, not_at_start);
     if (offset == 0) set_bm_info(not_at_start, bm);
   }
 
@@ -742,6 +746,7 @@
   }
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start);
   Type type() { return type_; }
@@ -813,6 +818,7 @@
       RegExpCompiler* compiler);
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start);
   void CalculateOffsets();
@@ -875,6 +881,7 @@
                                     bool not_at_start);
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start);
   AssertionNodeType type() { return type_; }
@@ -915,6 +922,7 @@
   }
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start);
 
@@ -942,6 +950,7 @@
   }
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start) {
     // Returning 0 from EatsAtLeast should ensure we never get here.
@@ -1034,6 +1043,7 @@
                                     bool not_at_start);
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start);
 
@@ -1086,10 +1096,11 @@
                                     bool not_at_start);
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start) {
     alternatives_->at(1).node()->FillInBMInfo(
-        offset, recursion_depth + 1, bm, not_at_start);
+        offset, recursion_depth + 1, budget - 1, bm, not_at_start);
     if (offset == 0) set_bm_info(not_at_start, bm);
   }
   // For a negative lookahead we don't emit the quick check for the
@@ -1121,6 +1132,7 @@
                                     bool not_at_start);
   virtual void FillInBMInfo(int offset,
                             int recursion_depth,
+                            int budget,
                             BoyerMooreLookahead* bm,
                             bool not_at_start);
   RegExpNode* loop_node() { return loop_node_; }