Factor out OSR-related graph-building functionality from hydrogen.cc.

src/hydrogen-osr.cc

+// Copyright 2013 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
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "hydrogen.h"
+#include "hydrogen-osr.h"
+
+namespace v8 {
+namespace internal {
+
+// True iff. we are compiling for OSR and the statement is the entry.
+bool HOsrBuilder::HasOsrEntryAt(IterationStatement* statement) {
+  return statement->OsrEntryId() == builder_->current_info()->osr_ast_id();
+}
+
+
+// Build a new loop header block and set it as the current block.
+HBasicBlock *HOsrBuilder::BuildLoopEntry() {
+  HBasicBlock* loop_entry = builder_->CreateLoopHeaderBlock();
+  builder_->current_block()->Goto(loop_entry);
+  builder_->set_current_block(loop_entry);
+  return loop_entry;
+}
+
+
+HBasicBlock* HOsrBuilder::BuildPossibleOsrLoopEntry(
+    IterationStatement* statement) {
+  // Check if there is an OSR here first.
+  if (!HasOsrEntryAt(statement)) return BuildLoopEntry();
+
+  Zone* zone = builder_->zone();
+  HGraph* graph = builder_->graph();
+
+  // only one OSR point per compile is allowed.
+  ASSERT(graph->osr() == NULL);
+
+  // remember this builder as the one OSR builder in the graph.
+  graph->set_osr(this);
+
+  HBasicBlock* non_osr_entry = graph->CreateBasicBlock();
+  osr_entry_ = graph->CreateBasicBlock();
+  HValue* true_value = graph->GetConstantTrue();
+  HBranch* test = new(zone) HBranch(true_value, non_osr_entry, osr_entry_);
+  builder_->current_block()->Finish(test);
+
+  HBasicBlock* loop_predecessor = graph->CreateBasicBlock();
+  non_osr_entry->Goto(loop_predecessor);
+
+  builder_->set_current_block(osr_entry_);
+  osr_entry_->set_osr_entry();
+  BailoutId osr_entry_id = statement->OsrEntryId();
+
+  HEnvironment *environment = builder_->environment();
+  int first_expression_index = environment->first_expression_index();
+  int length = environment->length();
+  osr_values_ = new(zone) ZoneList<HUnknownOSRValue*>(length, zone);
+
+  for (int i = 0; i < first_expression_index; ++i) {
+    HUnknownOSRValue* osr_value = builder_->Add<HUnknownOSRValue>();
+    environment->Bind(i, osr_value);
+    osr_values_->Add(osr_value, zone);
+  }
+
+  if (first_expression_index != length) {
+    environment->Drop(length - first_expression_index);
+    for (int i = first_expression_index; i < length; ++i) {
+      HUnknownOSRValue* osr_value = builder_->Add<HUnknownOSRValue>();
+      environment->Push(osr_value);
+      osr_values_->Add(osr_value, zone);
+    }
+  }
+
+  builder_->AddSimulate(osr_entry_id);
+  builder_->Add<HOsrEntry>(osr_entry_id);
+  HContext* context = builder_->Add<HContext>();
+  environment->BindContext(context);
+  builder_->current_block()->Goto(loop_predecessor);
+  loop_predecessor->SetJoinId(statement->EntryId());
+  builder_->set_current_block(loop_predecessor);
+
+  // Create the final loop entry
+  osr_loop_entry_ = BuildLoopEntry();
+  return osr_loop_entry_;
+}
+
+
+void HOsrBuilder::FinishGraph() {
+  // do nothing for now.
+}
+
+
+void HOsrBuilder::FinishOsrValues() {
+  const ZoneList<HPhi*>* phis = osr_loop_entry_->phis();
+  for (int j = 0; j < phis->length(); j++) {
+    HPhi* phi = phis->at(j);
+    osr_values_->at(phi->merged_index())->set_incoming_value(phi);
+  }
+}
+
+} }  // namespace v8::internal