[turbofan] Implement OSR for outer loops.

src/compiler/ast-graph-builder.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/ast-graph-builder.h"
 
 #include "src/compiler.h"
 #include "src/compiler/ast-loop-assignment-analyzer.h"
 #include "src/compiler/control-builders.h"
 #include "src/compiler/machine-operator.h"
@@ skipping 44 matching lines @@
 
 
 bool AstGraphBuilder::CreateGraph() {
   Scope* scope = info()->scope();
   DCHECK(graph() != NULL);
 
   // Set up the basic structure of the graph.
   int parameter_count = info()->num_parameters();
   graph()->SetStart(graph()->NewNode(common()->Start(parameter_count)));
 
+  Node* start = graph()->start();
   // Initialize the top-level environment.
-  Environment env(this, scope, graph()->start());
+  Environment env(this, scope, start);
   set_environment(&env);
 
+  if (info()->is_osr()) {
+    // Use OSR normal entry as the start of the top-level environment.
+    // It will be replaced with {Dead} after typing and optimizations.
+    NewNode(common()->OsrNormalEntry());
+  }
+
   // Initialize the incoming context.
   Node* outer_context = GetFunctionContext();
   set_current_context(outer_context);
 
   // Build receiver check for sloppy mode if necessary.
   // TODO(mstarzinger/verwaest): Should this be moved back into the CallIC?
   Node* original_receiver = env.Lookup(scope->receiver());
   Node* patched_receiver = BuildPatchReceiverToGlobalProxy(original_receiver);
   env.Bind(scope->receiver(), patched_receiver);
 
@@ skipping 503 matching lines @@
     VisitStatements(clause->statements());
     compare_switch.EndCase();
   }
 
   compare_switch.EndSwitch();
 }
 
 
 void AstGraphBuilder::VisitDoWhileStatement(DoWhileStatement* stmt) {
   LoopBuilder while_loop(this);
-  while_loop.BeginLoop(GetVariablesAssignedInLoop(stmt));
+  while_loop.BeginLoop(GetVariablesAssignedInLoop(stmt), IsOsrLoopEntry(stmt));
   VisitIterationBody(stmt, &while_loop, 0);
   while_loop.EndBody();
   VisitForTest(stmt->cond());
   Node* condition = environment()->Pop();
   while_loop.BreakUnless(condition);
   while_loop.EndLoop();
 }
 
 
 void AstGraphBuilder::VisitWhileStatement(WhileStatement* stmt) {
   LoopBuilder while_loop(this);
-  while_loop.BeginLoop(GetVariablesAssignedInLoop(stmt));
+  while_loop.BeginLoop(GetVariablesAssignedInLoop(stmt), IsOsrLoopEntry(stmt));
   VisitForTest(stmt->cond());
   Node* condition = environment()->Pop();
   while_loop.BreakUnless(condition);
   VisitIterationBody(stmt, &while_loop, 0);
   while_loop.EndBody();
   while_loop.EndLoop();
 }
 
 
 void AstGraphBuilder::VisitForStatement(ForStatement* stmt) {
   LoopBuilder for_loop(this);
   VisitIfNotNull(stmt->init());
-  for_loop.BeginLoop(GetVariablesAssignedInLoop(stmt));
+  for_loop.BeginLoop(GetVariablesAssignedInLoop(stmt), IsOsrLoopEntry(stmt));
   if (stmt->cond() != NULL) {
     VisitForTest(stmt->cond());
     Node* condition = environment()->Pop();
     for_loop.BreakUnless(condition);
   } else {
     for_loop.BreakUnless(jsgraph()->TrueConstant());
   }
   VisitIterationBody(stmt, &for_loop, 0);
   for_loop.EndBody();
   VisitIfNotNull(stmt->next());
@@ skipping 55 matching lines @@
       environment()->Pop();
       have_no_properties.Else();
       {
         // Construct the rest of the environment.
         environment()->Push(cache_type);
         environment()->Push(cache_array);
         environment()->Push(cache_length);
         environment()->Push(jsgraph()->ZeroConstant());
         // PrepareForBailoutForId(stmt->BodyId(), NO_REGISTERS);
         LoopBuilder for_loop(this);
-        for_loop.BeginLoop(GetVariablesAssignedInLoop(stmt));
+        for_loop.BeginLoop(GetVariablesAssignedInLoop(stmt),
+                           IsOsrLoopEntry(stmt));
         // Check loop termination condition.
         Node* index = environment()->Peek(0);
         Node* exit_cond =
             NewNode(javascript()->LessThan(), index, cache_length);
         // TODO(jarin): provide real bailout id.
         PrepareFrameState(exit_cond, BailoutId::None());
         for_loop.BreakUnless(exit_cond);
         // TODO(dcarney): this runtime call should be a handful of
         //                simplified instructions that
         //                basically produce
@@ skipping 1498 matching lines @@
   Node* tag = NewNode(jsgraph()->machine()->UintLessThan(), limit, stack);
   stack_check.If(tag, BranchHint::kTrue);
   stack_check.Then();
   stack_check.Else();
   Node* guard = NewNode(javascript()->CallRuntime(Runtime::kStackGuard, 0));
   stack_check.End();
   return guard;
 }
 
 
+bool AstGraphBuilder::IsOsrLoopEntry(IterationStatement* stmt) {
+  return info()->osr_ast_id() == stmt->OsrEntryId();
+}
+
+
 void AstGraphBuilder::PrepareFrameState(Node* node, BailoutId ast_id,
                                         OutputFrameStateCombine combine) {
   if (OperatorProperties::HasFrameStateInput(node->op())) {
     DCHECK(NodeProperties::GetFrameStateInput(node)->opcode() ==
            IrOpcode::kDead);
     NodeProperties::ReplaceFrameStateInput(
         node, environment()->Checkpoint(ast_id, combine));
   }
 }
 
 
 BitVector* AstGraphBuilder::GetVariablesAssignedInLoop(
     IterationStatement* stmt) {
   if (loop_assignment_analysis_ == NULL) return NULL;
   return loop_assignment_analysis_->GetVariablesAssignedInLoop(stmt);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8