Remove all functionality from class HSubgraph.

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 464 matching lines @@
 HConstant* HGraph::GetConstantTrue() {
   return GetConstant(&constant_true_, Heap::true_value());
 }
 
 
 HConstant* HGraph::GetConstantFalse() {
   return GetConstant(&constant_false_, Heap::false_value());
 }
 
 
-void HSubgraph::AppendJoin(HBasicBlock* first,
-                           HBasicBlock* second,
-                           int join_id) {
+HBasicBlock* HGraphBuilder::CreateJoin(HBasicBlock* first,
+                                       HBasicBlock* second,
+                                       int join_id) {
   if (first == NULL) {
-    exit_block_ = second;
+    return second;
   } else if (second == NULL) {
-    exit_block_ = first;
+    return first;
   } else {
     HBasicBlock* join_block = graph_->CreateBasicBlock();
     first->Goto(join_block);
     second->Goto(join_block);
     join_block->SetJoinId(join_id);
-    exit_block_ = join_block;
+    return join_block;
   }
 }
 
 
-void HSubgraph::ResolveContinue(IterationStatement* statement,
-                                HBasicBlock* continue_block) {
+HBasicBlock* HGraphBuilder::JoinContinue(IterationStatement* statement,
+                                         HBasicBlock* exit_block,
+                                         HBasicBlock* continue_block) {
   if (continue_block != NULL) {
     continue_block->SetJoinId(statement->ContinueId());
   }
-  exit_block_ =
-      JoinBlocks(exit_block(), continue_block, statement->ContinueId());
+  return CreateJoin(exit_block, continue_block, statement->ContinueId());
 }
 
 
-HBasicBlock* HSubgraph::JoinBlocks(HBasicBlock* a, HBasicBlock* b, int id) {
-  if (a == NULL) return b;
-  if (b == NULL) return a;
-  HBasicBlock* target = graph_->CreateBasicBlock();
-  a->Goto(target);
-  b->Goto(target);
-  target->SetJoinId(id);
-  return target;
+HBasicBlock* HGraphBuilder::CreateEndless(IterationStatement* statement,
+                                          HBasicBlock* body_entry,
+                                          HBasicBlock* body_exit,
+                                          HBasicBlock* break_block) {
+  if (body_exit != NULL) body_exit->Goto(body_entry, true);
+  if (break_block != NULL) break_block->SetJoinId(statement->ExitId());
+  body_entry->PostProcessLoopHeader(statement);
+  return break_block;
 }
 
 
-void HSubgraph::AppendEndless(IterationStatement* statement,
-                              HBasicBlock* body_entry,
-                              HBasicBlock* body_exit,
-                              HBasicBlock* break_block) {
-  if (exit_block() != NULL) {
-    exit_block()->Goto(body_entry, false);
-  }
-  if (body_exit != NULL) {
-    body_exit->Goto(body_entry, true);
-  }
+HBasicBlock* HGraphBuilder::CreateDoWhile(IterationStatement* statement,
+                                          HBasicBlock* body_entry,
+                                          HBasicBlock* go_back,
+                                          HBasicBlock* exit_block,
+                                          HBasicBlock* break_block) {
+  if (go_back != NULL) go_back->Goto(body_entry, true);
   if (break_block != NULL) break_block->SetJoinId(statement->ExitId());
-  exit_block_ = break_block;
+  HBasicBlock* new_exit =
+      CreateJoin(exit_block, break_block, statement->ExitId());
   body_entry->PostProcessLoopHeader(statement);
+  return new_exit;
 }
 
 
-void HSubgraph::AppendDoWhile(IterationStatement* statement,
-                              HBasicBlock* body_entry,
-                              HBasicBlock* go_back,
-                              HBasicBlock* exit_block,
-                              HBasicBlock* break_block) {
-  if (this->exit_block() != NULL) {
-    this->exit_block()->Goto(body_entry, false);
+HBasicBlock* HGraphBuilder::CreateWhile(IterationStatement* statement,
+                                        HBasicBlock* condition_entry,
+                                        HBasicBlock* exit_block,
+                                        HBasicBlock* body_exit,
+                                        HBasicBlock* break_block,
+                                        HBasicBlock* loop_entry,
+                                        HBasicBlock* loop_exit) {
+  if (break_block != NULL) break_block->SetJoinId(statement->ExitId());
+  HBasicBlock* new_exit =
+      CreateJoin(exit_block, break_block, statement->ExitId());
+
+  if (loop_entry != NULL) {
+    if (body_exit != NULL) body_exit->Goto(loop_entry, true);
+    loop_entry->SetJoinId(statement->EntryId());
+    new_exit = CreateJoin(new_exit, loop_exit, statement->ExitId());
+  } else {

[fschneider, 2011/02/24 13:09:44]

here you could write 

} else if (...) {

}

[Kevin Millikin (Chromium), 2011/02/28 08:53:29]

Good catch.  I'll hold off for now because the "if (blah != NULL)
blah->Goto(whocares);" seems like an idiom that we might abstract, so I'd like
to keep it exactly that way in the code.

+    if (body_exit != NULL) body_exit->Goto(condition_entry, true);
   }
-  if (go_back != NULL) {
-    go_back->Goto(body_entry, true);
-  }
-  if (break_block != NULL) break_block->SetJoinId(statement->ExitId());
-  exit_block_ =
-      JoinBlocks(exit_block, break_block, statement->ExitId());
-  body_entry->PostProcessLoopHeader(statement);
+  condition_entry->PostProcessLoopHeader(statement);
+  return new_exit;
 }
 
 
-void HSubgraph::AppendWhile(IterationStatement* statement,
-                            HBasicBlock* condition_entry,
-                            HBasicBlock* exit_block,
-                            HBasicBlock* body_exit,
-                            HBasicBlock* break_block,
-                            HBasicBlock* loop_entry,
-                            HBasicBlock* loop_exit) {
-  if (this->exit_block() != NULL) {
-    this->exit_block()->Goto(condition_entry, false);
-  }
-
-  if (break_block != NULL) break_block->SetJoinId(statement->ExitId());
-  exit_block_ =
-      JoinBlocks(exit_block, break_block, statement->ExitId());
-
-  if (loop_entry != NULL) {
-    if (body_exit != NULL) {
-      body_exit->Goto(loop_entry, true);
-    }
-    loop_entry->SetJoinId(statement->EntryId());
-    exit_block_ = JoinBlocks(exit_block_, loop_exit, statement->ExitId());
-  } else {
-    if (body_exit != NULL) {
-      body_exit->Goto(condition_entry, true);
-    }
-  }
-  condition_entry->PostProcessLoopHeader(statement);
+void HBasicBlock::FinishExit(HControlInstruction* instruction) {
+  Finish(instruction);
+  ClearEnvironment();
 }
 
 
-void HSubgraph::Append(BreakableStatement* stmt,
-                       HBasicBlock* entry_block,
-                       HBasicBlock* exit_block,
-                       HBasicBlock* break_block) {
-  exit_block_->Goto(entry_block);
-  exit_block_ = exit_block;
-
-  if (stmt != NULL) {
-    entry_block->SetJoinId(stmt->EntryId());
-    if (break_block != NULL) break_block->SetJoinId(stmt->EntryId());
-    exit_block_ = JoinBlocks(exit_block, break_block, stmt->ExitId());
-  }
-}
-
-
-void HSubgraph::FinishExit(HControlInstruction* instruction) {
-  ASSERT(exit_block() != NULL);
-  exit_block_->Finish(instruction);
-  exit_block_->ClearEnvironment();
-  exit_block_ = NULL;
-}
-
-
 HGraph::HGraph(CompilationInfo* info)
     : HSubgraph(this),
       next_block_id_(0),
       info_(info),
       blocks_(8),
       values_(16),
       phi_list_(NULL) {
   start_environment_ = new HEnvironment(NULL, info->scope(), info->closure());
   start_environment_->set_ast_id(info->function()->id());
 }
@@ skipping 1538 matching lines @@
     current_subgraph_ = graph_;
 
     Scope* scope = info->scope();
     SetupScope(scope);
     VisitDeclarations(scope->declarations());
 
     AddInstruction(new HStackCheck());
 
     ZoneList<Statement*>* stmts = info->function()->body();
     HSubgraph* body = CreateGotoSubgraph(environment());
+    current_block()->Goto(body->entry_block());
     AddToSubgraph(body, stmts);
     if (HasStackOverflow()) return NULL;
-    current_subgraph_->Append(NULL,
-                              body->entry_block(),
-                              body->exit_block(),
-                              NULL);
     body->entry_block()->SetJoinId(info->function()->id());
+    set_current_block(body->exit_block());
 
     if (graph()->exit_block() != NULL) {
-      graph_->FinishExit(new HReturn(graph_->GetConstantUndefined()));
+      HReturn* instr = new HReturn(graph()->GetConstantUndefined());
+      graph()->exit_block()->FinishExit(instr);
+      graph()->set_exit_block(NULL);
     }
   }
 
   graph_->OrderBlocks();
   graph_->AssignDominators();
   graph_->EliminateRedundantPhis();
   if (!graph_->CollectPhis()) {
     Bailout("Phi-use of arguments object");
     return NULL;
   }
@@ skipping 180 matching lines @@
   block->SetInitialEnvironment(new_env);
   subgraph->Initialize(block);
   subgraph->entry_block()->AttachLoopInformation();
   return subgraph;
 }
 
 
 void HGraphBuilder::VisitBlock(Block* stmt) {
   if (stmt->labels() != NULL) {
     HSubgraph* block_graph = CreateGotoSubgraph(environment());
+    current_block()->Goto(block_graph->entry_block());
+    block_graph->entry_block()->SetJoinId(stmt->EntryId());
     BreakAndContinueInfo break_info(stmt);
     { BreakAndContinueScope push(&break_info, this);
       ADD_TO_SUBGRAPH(block_graph, stmt->statements());
     }
-    subgraph()->Append(stmt,
-                       block_graph->entry_block(),
-                       block_graph->exit_block(),
-                       break_info.break_block());
+    HBasicBlock* break_block = break_info.break_block();
+    if (break_block != NULL) break_block->SetJoinId(stmt->EntryId());
+    set_current_block(CreateJoin(block_graph->exit_block(),
+                                 break_block,
+                                 stmt->ExitId()));
   } else {
     VisitStatements(stmt->statements());
   }
 }
 
 
 void HGraphBuilder::VisitExpressionStatement(ExpressionStatement* stmt) {
   VisitForEffect(stmt->expression());
 }
 
@@ skipping 15 matching lines @@
     VISIT_FOR_CONTROL(stmt->condition(),
                       then_graph->entry_block(),
                       else_graph->entry_block());
 
     then_graph->entry_block()->SetJoinId(stmt->ThenId());
     ADD_TO_SUBGRAPH(then_graph, stmt->then_statement());
 
     else_graph->entry_block()->SetJoinId(stmt->ElseId());
     ADD_TO_SUBGRAPH(else_graph, stmt->else_statement());
 
-    current_subgraph_->AppendJoin(then_graph->exit_block(),
-                                  else_graph->exit_block(),
-                                  stmt->id());
+    set_current_block(CreateJoin(then_graph->exit_block(),
+                                 else_graph->exit_block(),
+                                 stmt->id()));
   }
 }
 
 
 HBasicBlock* HGraphBuilder::BreakAndContinueScope::Get(
     BreakableStatement* stmt,
     BreakType type) {
   BreakAndContinueScope* current = this;
   while (current != NULL && current->info()->target() != stmt) {
     current = current->next();
@@ skipping 35 matching lines @@
   set_current_block(NULL);
 }
 
 
 void HGraphBuilder::VisitReturnStatement(ReturnStatement* stmt) {
   AstContext* context = call_context();
   if (context == NULL) {
     // Not an inlined return, so an actual one.
     VISIT_FOR_VALUE(stmt->expression());
     HValue* result = environment()->Pop();
-    subgraph()->FinishExit(new HReturn(result));
+    current_block()->FinishExit(new HReturn(result));
+    set_current_block(NULL);
   } else {
     // Return from an inlined function, visit the subexpression in the
     // expression context of the call.
     if (context->IsTest()) {
       TestContext* test = TestContext::cast(context);
       VisitForControl(stmt->expression(),
                       test->if_true(),
                       test->if_false());
     } else {
       HValue* return_value = NULL;
       if (context->IsEffect()) {
         VISIT_FOR_EFFECT(stmt->expression());
         return_value = graph()->GetConstantUndefined();
       } else {
         ASSERT(context->IsValue());
         VISIT_FOR_VALUE(stmt->expression());
         return_value = environment()->Pop();
       }
       current_block()->AddLeaveInlined(return_value,
-                                                function_return_);
+                                       function_return_);
       set_current_block(NULL);
     }
   }
 }
 
 
 void HGraphBuilder::VisitWithEnterStatement(WithEnterStatement* stmt) {
   BAILOUT("WithEnterStatement");
 }
 
@@ skipping 168 matching lines @@
   } else {
     set_current_block(NULL);
   }
 }
 
 bool HGraph::HasOsrEntryAt(IterationStatement* statement) {
   return statement->OsrEntryId() == info()->osr_ast_id();
 }
 
 
-void HSubgraph::PreProcessOsrEntry(IterationStatement* statement) {
+void HGraphBuilder::PreProcessOsrEntry(IterationStatement* statement) {
   if (!graph()->HasOsrEntryAt(statement)) return;
 
   HBasicBlock* non_osr_entry = graph()->CreateBasicBlock();
   HBasicBlock* osr_entry = graph()->CreateBasicBlock();
   HValue* true_value = graph()->GetConstantTrue();
   HTest* test = new HTest(true_value, non_osr_entry, osr_entry);
-  exit_block()->Finish(test);
+  current_block()->Finish(test);
 
   HBasicBlock* loop_predecessor = graph()->CreateBasicBlock();
   non_osr_entry->Goto(loop_predecessor);
 
+  set_current_block(osr_entry);
   int osr_entry_id = statement->OsrEntryId();
   // We want the correct environment at the OsrEntry instruction.  Build
   // it explicitly.  The expression stack should be empty.
-  int count = osr_entry->last_environment()->length();
-  ASSERT(count == (osr_entry->last_environment()->parameter_count() +
-                   osr_entry->last_environment()->local_count()));
+  int count = environment()->length();
+  ASSERT(count ==
+         (environment()->parameter_count() + environment()->local_count()));
   for (int i = 0; i < count; ++i) {
     HUnknownOSRValue* unknown = new HUnknownOSRValue;
-    osr_entry->AddInstruction(unknown);
-    osr_entry->last_environment()->Bind(i, unknown);
+    AddInstruction(unknown);
+    environment()->Bind(i, unknown);
   }
 
-  osr_entry->AddSimulate(osr_entry_id);
-  osr_entry->AddInstruction(new HOsrEntry(osr_entry_id));
-  osr_entry->Goto(loop_predecessor);
+  AddSimulate(osr_entry_id);
+  AddInstruction(new HOsrEntry(osr_entry_id));
+  current_block()->Goto(loop_predecessor);
   loop_predecessor->SetJoinId(statement->EntryId());
-  set_exit_block(loop_predecessor);
+  set_current_block(loop_predecessor);
 }
 
 
 void HGraphBuilder::VisitDoWhileStatement(DoWhileStatement* stmt) {
   ASSERT(current_block() != NULL);
-  subgraph()->PreProcessOsrEntry(stmt);
+  PreProcessOsrEntry(stmt);
 
   HSubgraph* body_graph = CreateLoopHeaderSubgraph(environment());
+  current_block()->Goto(body_graph->entry_block(), false);
   BreakAndContinueInfo break_info(stmt);
   { BreakAndContinueScope push(&break_info, this);
     ADD_TO_SUBGRAPH(body_graph, stmt->body());
   }
-  body_graph->ResolveContinue(stmt, break_info.continue_block());
+  HBasicBlock* body_exit = JoinContinue(stmt,
+                                        body_graph->exit_block(),
+                                        break_info.continue_block());
+  body_graph->set_exit_block(body_exit);
 
   if (body_graph->exit_block() == NULL || stmt->cond()->ToBooleanIsTrue()) {
-    subgraph()->AppendEndless(stmt,
-                              body_graph->entry_block(),
-                              body_graph->exit_block(),
-                              break_info.break_block());
+    set_current_block(CreateEndless(stmt,
+                                    body_graph->entry_block(),
+                                    body_graph->exit_block(),
+                                    break_info.break_block()));
   } else {
     HSubgraph* go_back = CreateEmptySubgraph();
     HSubgraph* exit = CreateEmptySubgraph();
     {
       SubgraphScope scope(this, body_graph);
       VISIT_FOR_CONTROL(stmt->cond(),
                         go_back->entry_block(),
                         exit->entry_block());
       go_back->entry_block()->SetJoinId(stmt->BackEdgeId());
       exit->entry_block()->SetJoinId(stmt->ExitId());
     }
-    subgraph()->AppendDoWhile(stmt,
-                              body_graph->entry_block(),
-                              go_back->exit_block(),
-                              exit->exit_block(),
-                              break_info.break_block());
+    set_current_block(CreateDoWhile(stmt,
+                                    body_graph->entry_block(),
+                                    go_back->exit_block(),
+                                    exit->exit_block(),
+                                    break_info.break_block()));
   }
 }
 
 
 void HGraphBuilder::VisitWhileStatement(WhileStatement* stmt) {
   ASSERT(current_block() != NULL);
-  subgraph()->PreProcessOsrEntry(stmt);
+  PreProcessOsrEntry(stmt);
 
   HSubgraph* cond_graph = NULL;
   HSubgraph* body_graph = NULL;
   HSubgraph* exit_graph = NULL;
 
   // If the condition is constant true, do not generate a condition subgraph.
   if (stmt->cond()->ToBooleanIsTrue()) {
     body_graph = CreateLoopHeaderSubgraph(environment());
+    current_block()->Goto(body_graph->entry_block(), false);
   } else {
     cond_graph = CreateLoopHeaderSubgraph(environment());
+    current_block()->Goto(cond_graph->entry_block(), false);
     body_graph = CreateEmptySubgraph();
     exit_graph = CreateEmptySubgraph();
     {
       SubgraphScope scope(this, cond_graph);
       VISIT_FOR_CONTROL(stmt->cond(),
                         body_graph->entry_block(),
                         exit_graph->entry_block());
       body_graph->entry_block()->SetJoinId(stmt->BodyId());
       exit_graph->entry_block()->SetJoinId(stmt->ExitId());
     }
   }
 
   BreakAndContinueInfo break_info(stmt);
   { BreakAndContinueScope push(&break_info, this);
     ADD_TO_SUBGRAPH(body_graph, stmt->body());
   }
-  body_graph->ResolveContinue(stmt, break_info.continue_block());
+  HBasicBlock* body_exit = JoinContinue(stmt,
+                                        body_graph->exit_block(),
+                                        break_info.continue_block());
+  body_graph->set_exit_block(body_exit);
 
   if (cond_graph != NULL) {
-    AppendPeeledWhile(stmt,
-                      cond_graph->entry_block(),
-                      exit_graph->exit_block(),
-                      body_graph->exit_block(),
-                      break_info.break_block());
+    set_current_block(CreatePeeledWhile(stmt,
+                                        cond_graph->entry_block(),
+                                        exit_graph->exit_block(),
+                                        body_graph->exit_block(),
+                                        break_info.break_block()));
   } else {
     // TODO(fschneider): Implement peeling for endless loops as well.
-    subgraph()->AppendEndless(stmt,
-                              body_graph->entry_block(),
-                              body_graph->exit_block(),
-                              break_info.break_block());
+    set_current_block(CreateEndless(stmt,
+                                    body_graph->entry_block(),
+                                    body_graph->exit_block(),
+                                    break_info.break_block()));
   }
 }
 
 
-void HGraphBuilder::AppendPeeledWhile(IterationStatement* stmt,
-                                      HBasicBlock* condition_entry,
-                                      HBasicBlock* exit_block,
-                                      HBasicBlock* body_exit,
-                                      HBasicBlock* break_block) {
+HBasicBlock* HGraphBuilder::CreatePeeledWhile(IterationStatement* stmt,
+                                              HBasicBlock* condition_entry,
+                                              HBasicBlock* exit_block,
+                                              HBasicBlock* body_exit,
+                                              HBasicBlock* break_block) {
   HBasicBlock* loop_entry = NULL;
   HBasicBlock* loop_exit = NULL;
   if (FLAG_use_peeling && body_exit != NULL && stmt != peeled_statement_) {
     // Save the last peeled iteration statement to prevent infinite recursion.
     IterationStatement* outer_peeled_statement = peeled_statement_;
     peeled_statement_ = stmt;
     HSubgraph* loop = CreateGotoSubgraph(body_exit->last_environment());
-    ADD_TO_SUBGRAPH(loop, stmt);
+    AddToSubgraph(loop, stmt);
     peeled_statement_ = outer_peeled_statement;
+    if (HasStackOverflow()) return NULL;
     loop_entry = loop->entry_block();
     loop_exit = loop->exit_block();
   }
-  subgraph()->AppendWhile(stmt,
-                          condition_entry,
-                          exit_block,
-                          body_exit,
-                          break_block,
-                          loop_entry,
-                          loop_exit);
+  return CreateWhile(stmt,
+                     condition_entry,
+                     exit_block,
+                     body_exit,
+                     break_block,
+                     loop_entry,
+                     loop_exit);
 }
 
 
 void HGraphBuilder::VisitForStatement(ForStatement* stmt) {
   // Only visit the init statement in the peeled part of the loop.
   if (stmt->init() != NULL && peeled_statement_ != stmt) {
     Visit(stmt->init());
     CHECK_BAILOUT;
   }
   ASSERT(current_block() != NULL);
-  subgraph()->PreProcessOsrEntry(stmt);
+  PreProcessOsrEntry(stmt);
 
   HSubgraph* cond_graph = NULL;
   HSubgraph* body_graph = NULL;
   HSubgraph* exit_graph = NULL;
   if (stmt->cond() != NULL) {
     cond_graph = CreateLoopHeaderSubgraph(environment());
+    current_block()->Goto(cond_graph->entry_block(), false);
     body_graph = CreateEmptySubgraph();
     exit_graph = CreateEmptySubgraph();
     {
       SubgraphScope scope(this, cond_graph);
       VISIT_FOR_CONTROL(stmt->cond(),
                         body_graph->entry_block(),
                         exit_graph->entry_block());
       body_graph->entry_block()->SetJoinId(stmt->BodyId());
       exit_graph->entry_block()->SetJoinId(stmt->ExitId());
     }
   } else {
     body_graph = CreateLoopHeaderSubgraph(environment());
+    current_block()->Goto(body_graph->entry_block(), false);
   }
   BreakAndContinueInfo break_info(stmt);
   { BreakAndContinueScope push(&break_info, this);
     ADD_TO_SUBGRAPH(body_graph, stmt->body());
   }
 
   HSubgraph* next_graph = NULL;
-  body_graph->ResolveContinue(stmt, break_info.continue_block());
+  HBasicBlock* body_exit = JoinContinue(stmt,
+                                        body_graph->exit_block(),
+                                        break_info.continue_block());
+  body_graph->set_exit_block(body_exit);
 
   if (stmt->next() != NULL && body_graph->exit_block() != NULL) {
     next_graph =
         CreateGotoSubgraph(body_graph->exit_block()->last_environment());
+    body_graph->exit_block()->Goto(next_graph->entry_block());
+    next_graph->entry_block()->SetJoinId(stmt->ContinueId());
     ADD_TO_SUBGRAPH(next_graph, stmt->next());
-    body_graph->Append(NULL,
-                       next_graph->entry_block(),
-                       next_graph->exit_block(),
-                       NULL);
-    next_graph->entry_block()->SetJoinId(stmt->ContinueId());
+    body_graph->set_exit_block(next_graph->exit_block());
   }
 
   if (cond_graph != NULL) {
-    AppendPeeledWhile(stmt,
-                      cond_graph->entry_block(),
-                      exit_graph->exit_block(),
-                      body_graph->exit_block(),
-                      break_info.break_block());
+    set_current_block(CreatePeeledWhile(stmt,
+                                        cond_graph->entry_block(),
+                                        exit_graph->exit_block(),
+                                        body_graph->exit_block(),
+                                        break_info.break_block()));
   } else {
-    subgraph()->AppendEndless(stmt,
-                              body_graph->entry_block(),
-                              body_graph->exit_block(),
-                              break_info.break_block());
+    set_current_block(CreateEndless(stmt,
+                                    body_graph->entry_block(),
+                                    body_graph->exit_block(),
+                                    break_info.break_block()));
   }
 }
 
 
 void HGraphBuilder::VisitForInStatement(ForInStatement* stmt) {
   BAILOUT("ForInStatement");
 }
 
 
 void HGraphBuilder::VisitTryCatchStatement(TryCatchStatement* stmt) {
@@ skipping 33 matching lines @@
   VISIT_FOR_CONTROL(expr->condition(),
                     then_graph->entry_block(),
                     else_graph->entry_block());
 
   then_graph->entry_block()->SetJoinId(expr->ThenId());
   ADD_TO_SUBGRAPH(then_graph, expr->then_expression());
 
   else_graph->entry_block()->SetJoinId(expr->ElseId());
   ADD_TO_SUBGRAPH(else_graph, expr->else_expression());
 
-  current_subgraph_->AppendJoin(then_graph->exit_block(),
-                                else_graph->exit_block(),
-                                expr->id());
+  set_current_block(CreateJoin(then_graph->exit_block(),
+                               else_graph->exit_block(),
+                               expr->id()));
   ast_context()->ReturnValue(Pop());
 }
 
 
 void HGraphBuilder::LookupGlobalPropertyCell(Variable* var,
                                              LookupResult* lookup,
                                              bool is_store) {
   if (var->is_this()) {
     BAILOUT("global this reference");
   }
@@ skipping 357 matching lines @@
     Push(value);
     instr->set_position(expr->position());
     AddInstruction(instr);
     if (instr->HasSideEffects()) AddSimulate(expr->AssignmentId());
     ast_context()->ReturnValue(Pop());
   } else {
     // Build subgraph for generic store through IC.
     HSubgraph* default_graph = CreateBranchSubgraph(environment());
     { SubgraphScope scope(this, default_graph);
       if (!needs_generic && FLAG_deoptimize_uncommon_cases) {
-        default_graph->FinishExit(new HDeoptimize());
+        default_graph->exit_block()->FinishExit(new HDeoptimize());
+        default_graph->set_exit_block(NULL);
       } else {
         HInstruction* instr = BuildStoreNamedGeneric(object, name, value);
         Push(value);
         instr->set_position(expr->position());
         AddInstruction(instr);
       }
     }
 
     HBasicBlock* new_exit_block =
         BuildTypeSwitch(object, &maps, &subgraphs, default_graph, expr->id());
@@ skipping 266 matching lines @@
   // assignments, count operations, or for-in.  Consequently throw can
   // currently only occur in an effect context.
   ASSERT(ast_context()->IsEffect());
   VISIT_FOR_VALUE(expr->exception());
 
   HValue* value = environment()->Pop();
   HThrow* instr = new HThrow(value);
   instr->set_position(expr->position());
   AddInstruction(instr);
   AddSimulate(expr->id());
-  current_subgraph_->FinishExit(new HAbnormalExit);
+  current_block()->FinishExit(new HAbnormalExit);
+  set_current_block(NULL);
 }
 
 
 void HGraphBuilder::HandlePolymorphicLoadNamedField(Property* expr,
                                                     HValue* object,
                                                     ZoneMapList* types,
                                                     Handle<String> name) {
   int number_of_types = Min(types->length(), kMaxLoadPolymorphism);
   ZoneMapList maps(number_of_types);
   ZoneList<HSubgraph*> subgraphs(number_of_types);
@@ skipping 27 matching lines @@
   // generic load.
   if (maps.length() == 0) {
     HInstruction* instr = BuildLoadNamedGeneric(object, expr);
     instr->set_position(expr->position());
     ast_context()->ReturnInstruction(instr, expr->id());
   } else {
     // Build subgraph for generic load through IC.
     HSubgraph* default_graph = CreateBranchSubgraph(environment());
     { SubgraphScope scope(this, default_graph);
       if (!needs_generic && FLAG_deoptimize_uncommon_cases) {
-        default_graph->FinishExit(new HDeoptimize());
+        default_graph->exit_block()->FinishExit(new HDeoptimize());
+        default_graph->set_exit_block(NULL);
       } else {
         HInstruction* instr = BuildLoadNamedGeneric(object, expr);
         instr->set_position(expr->position());
         PushAndAdd(instr);
       }
     }
 
     HBasicBlock* new_exit_block =
         BuildTypeSwitch(object, &maps, &subgraphs, default_graph, expr->id());
     set_current_block(new_exit_block);
@@ skipping 337 matching lines @@
     AddInstruction(context);
     HCallNamed* call = new HCallNamed(context, name, argument_count);
     call->set_position(expr->position());
     PreProcessCall(call);
     ast_context()->ReturnInstruction(call, expr->id());
   } else {
     // Build subgraph for generic call through IC.
     HSubgraph* default_graph = CreateBranchSubgraph(environment());
     { SubgraphScope scope(this, default_graph);
       if (!needs_generic && FLAG_deoptimize_uncommon_cases) {
-        default_graph->FinishExit(new HDeoptimize());
+        default_graph->exit_block()->FinishExit(new HDeoptimize());
+        default_graph->set_exit_block(NULL);
       } else {
         HContext* context = new HContext;
         AddInstruction(context);
         HCallNamed* call = new HCallNamed(context, name, argument_count);
         call->set_position(expr->position());
         PreProcessCall(call);
         PushAndAdd(call);
       }
     }
 
@@ skipping 699 matching lines @@
                         false_graph->entry_block(),
                         true_graph->entry_block());
       true_graph->entry_block()->SetJoinId(expr->expression()->id());
       true_graph->exit_block()->last_environment()->Push(
           graph_->GetConstantTrue());
 
       false_graph->entry_block()->SetJoinId(expr->expression()->id());
       false_graph->exit_block()->last_environment()->Push(
           graph_->GetConstantFalse());
 
-      current_subgraph_->AppendJoin(true_graph->exit_block(),
-                                    false_graph->exit_block(),
-                                    expr->id());
+      set_current_block(CreateJoin(true_graph->exit_block(),
+                                   false_graph->exit_block(),
+                                   expr->id()));
       ast_context()->ReturnValue(Pop());
     } else {
       ASSERT(ast_context()->IsEffect());
       VISIT_FOR_EFFECT(expr->expression());
     }
 
   } else if (op == Token::BIT_NOT || op == Token::SUB) {
     VISIT_FOR_VALUE(expr->expression());
     HValue* value = Pop();
     HInstruction* instr = NULL;
@@ skipping 1380 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify();
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal