Fix a bug with deoptimization from inside the default-clause of a switch-statement.

src/hydrogen.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2738 matching lines @@
     not_string_block = graph()->CreateBasicBlock();
 
     string_check->SetSuccessorAt(0, first_test_block);
     string_check->SetSuccessorAt(1, not_string_block);
     current_block()->Finish(string_check);
 
     set_current_block(first_test_block);
   }
 
   // 2. Build all the tests, with dangling true branches
+  int default_id = AstNode::kNoNumber;
   for (int i = 0; i < clause_count; ++i) {
     CaseClause* clause = clauses->at(i);
-    if (clause->is_default()) continue;
-
+    if (clause->is_default()) {
+      default_id = clause->EntryId();
+      continue;
+    }
     if (switch_type == SMI_SWITCH) {
       clause->RecordTypeFeedback(oracle());
     }
 
     // Generate a compare and branch.
     CHECK_ALIVE(VisitForValue(clause->label()));
     HValue* label_value = Pop();
 
     HBasicBlock* next_test_block = graph()->CreateBasicBlock();
     HBasicBlock* body_block = graph()->CreateBasicBlock();
@@ skipping 26 matching lines @@
     current_block()->Finish(compare);
 
     set_current_block(next_test_block);
   }
 
   // Save the current block to use for the default or to join with the
   // exit.  This block is NULL if we deoptimized.
   HBasicBlock* last_block = current_block();
 
   if (not_string_block != NULL) {
-    last_block = CreateJoin(last_block, not_string_block, stmt->ExitId());
+    int join_id = (default_id != AstNode::kNoNumber)
+        ? default_id
+        : stmt->ExitId();
+    last_block = CreateJoin(last_block, not_string_block, join_id);
   }
 
   // 3. Loop over the clauses and the linked list of tests in lockstep,
   // translating the clause bodies.
   HBasicBlock* curr_test_block = first_test_block;
   HBasicBlock* fall_through_block = NULL;
 
   BreakAndContinueInfo break_info(stmt);
   { BreakAndContinueScope push(&break_info, this);
     for (int i = 0; i < clause_count; ++i) {
@@ skipping 4401 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal