src/v8/src/hydrogen-osr.cc

   1 // Copyright 2013 the V8 project authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "src/hydrogen.h"
   6 #include "src/hydrogen-osr.h"
   7
   8 namespace v8 {
   9 namespace internal {
  10
  11 // True iff. we are compiling for OSR and the statement is the entry.
  12 bool HOsrBuilder::HasOsrEntryAt(IterationStatement* statement) {
  13   return statement->OsrEntryId() == builder_->current_info()->osr_ast_id();
  14 }
  15
  16
  17 HBasicBlock* HOsrBuilder::BuildOsrLoopEntry(IterationStatement* statement) {
  18   DCHECK(HasOsrEntryAt(statement));
  19
  20   Zone* zone = builder_->zone();
  21   HGraph* graph = builder_->graph();
  22
  23   // only one OSR point per compile is allowed.
  24   DCHECK(graph->osr() == NULL);
  25
  26   // remember this builder as the one OSR builder in the graph.
  27   graph->set_osr(this);
  28
  29   HBasicBlock* non_osr_entry = graph->CreateBasicBlock();
  30   osr_entry_ = graph->CreateBasicBlock();
  31   HValue* true_value = graph->GetConstantTrue();
  32   HBranch* test = builder_->New<HBranch>(true_value, ToBooleanStub::Types(),
  33                                          non_osr_entry, osr_entry_);
  34   builder_->FinishCurrentBlock(test);
  35
  36   HBasicBlock* loop_predecessor = graph->CreateBasicBlock();
  37   builder_->Goto(non_osr_entry, loop_predecessor);
  38
  39   builder_->set_current_block(osr_entry_);
  40   osr_entry_->set_osr_entry();
  41   BailoutId osr_entry_id = statement->OsrEntryId();
  42
  43   HEnvironment *environment = builder_->environment();
  44   int first_expression_index = environment->first_expression_index();
  45   int length = environment->length();
  46   osr_values_ = new(zone) ZoneList<HUnknownOSRValue*>(length, zone);
  47
  48   for (int i = 0; i < first_expression_index; ++i) {
  49     HUnknownOSRValue* osr_value
  50         = builder_->Add<HUnknownOSRValue>(environment, i);
  51     environment->Bind(i, osr_value);
  52     osr_values_->Add(osr_value, zone);
  53   }
  54
  55   if (first_expression_index != length) {
  56     environment->Drop(length - first_expression_index);
  57     for (int i = first_expression_index; i < length; ++i) {
  58       HUnknownOSRValue* osr_value
  59           = builder_->Add<HUnknownOSRValue>(environment, i);
  60       environment->Push(osr_value);
  61       osr_values_->Add(osr_value, zone);
  62     }
  63   }
  64
  65   unoptimized_frame_slots_ =
  66       environment->local_count() + environment->push_count();
  67
  68   // Keep a copy of the old environment, since the OSR values need it
  69   // to figure out where exactly they are located in the unoptimized frame.
  70   environment = environment->Copy();
  71   builder_->current_block()->UpdateEnvironment(environment);
  72
  73   builder_->Add<HSimulate>(osr_entry_id);
  74   builder_->Add<HOsrEntry>(osr_entry_id);
  75   HContext* context = builder_->Add<HContext>();
  76   environment->BindContext(context);
  77   builder_->Goto(loop_predecessor);
  78   loop_predecessor->SetJoinId(statement->EntryId());
  79   builder_->set_current_block(loop_predecessor);
  80
  81   // Create the final loop entry
  82   osr_loop_entry_ = builder_->BuildLoopEntry();
  83   return osr_loop_entry_;
  84 }
  85
  86
  87 void HOsrBuilder::FinishGraph() {
  88   // do nothing for now.
  89 }
  90
  91
  92 void HOsrBuilder::FinishOsrValues() {
  93   const ZoneList<HPhi*>* phis = osr_loop_entry_->phis();
  94   for (int j = 0; j < phis->length(); j++) {
  95     HPhi* phi = phis->at(j);
  96     if (phi->HasMergedIndex()) {
  97       osr_values_->at(phi->merged_index())->set_incoming_value(phi);
  98     }
  99   }
 100 }
 101
 102 } }  // namespace v8::internal