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/crankshaft/hydrogen-osr.h"
6
7#include "src/crankshaft/hydrogen.h"
8
9namespace v8 {
10namespace internal {
11
12// True iff. we are compiling for OSR and the statement is the entry.
13bool HOsrBuilder::HasOsrEntryAt(IterationStatement* statement) {
14  return statement->OsrEntryId() == builder_->current_info()->osr_ast_id();
15}
16
17
18HBasicBlock* HOsrBuilder::BuildOsrLoopEntry(IterationStatement* statement) {
19  DCHECK(HasOsrEntryAt(statement));
20
21  Zone* zone = builder_->zone();
22  HGraph* graph = builder_->graph();
23
24  // only one OSR point per compile is allowed.
25  DCHECK(graph->osr() == NULL);
26
27  // remember this builder as the one OSR builder in the graph.
28  graph->set_osr(this);
29
30  HBasicBlock* non_osr_entry = graph->CreateBasicBlock();
31  osr_entry_ = graph->CreateBasicBlock();
32  HValue* true_value = graph->GetConstantTrue();
33  HBranch* test = builder_->New<HBranch>(true_value, ToBooleanICStub::Types(),
34                                         non_osr_entry, osr_entry_);
35  builder_->FinishCurrentBlock(test);
36
37  HBasicBlock* loop_predecessor = graph->CreateBasicBlock();
38  builder_->Goto(non_osr_entry, loop_predecessor);
39
40  builder_->set_current_block(osr_entry_);
41  osr_entry_->set_osr_entry();
42  BailoutId osr_entry_id = statement->OsrEntryId();
43
44  HEnvironment *environment = builder_->environment();
45  int first_expression_index = environment->first_expression_index();
46  int length = environment->length();
47  osr_values_ = new(zone) ZoneList<HUnknownOSRValue*>(length, zone);
48
49  for (int i = 0; i < first_expression_index; ++i) {
50    HUnknownOSRValue* osr_value
51        = builder_->Add<HUnknownOSRValue>(environment, i);
52    environment->Bind(i, osr_value);
53    osr_values_->Add(osr_value, zone);
54  }
55
56  if (first_expression_index != length) {
57    environment->Drop(length - first_expression_index);
58    for (int i = first_expression_index; i < length; ++i) {
59      HUnknownOSRValue* osr_value
60          = builder_->Add<HUnknownOSRValue>(environment, i);
61      environment->Push(osr_value);
62      osr_values_->Add(osr_value, zone);
63    }
64  }
65
66  unoptimized_frame_slots_ =
67      environment->local_count() + environment->push_count();
68
69  // Keep a copy of the old environment, since the OSR values need it
70  // to figure out where exactly they are located in the unoptimized frame.
71  environment = environment->Copy();
72  builder_->current_block()->UpdateEnvironment(environment);
73
74  builder_->Add<HSimulate>(osr_entry_id);
75  builder_->Add<HOsrEntry>(osr_entry_id);
76  HContext* context = builder_->Add<HContext>();
77  environment->BindContext(context);
78  builder_->Goto(loop_predecessor);
79  loop_predecessor->SetJoinId(statement->EntryId());
80  builder_->set_current_block(loop_predecessor);
81
82  // Create the final loop entry
83  osr_loop_entry_ = builder_->BuildLoopEntry();
84  return osr_loop_entry_;
85}
86
87
88void HOsrBuilder::FinishGraph() {
89  // do nothing for now.
90}
91
92
93void HOsrBuilder::FinishOsrValues() {
94  const ZoneList<HPhi*>* phis = osr_loop_entry_->phis();
95  for (int j = 0; j < phis->length(); j++) {
96    HPhi* phi = phis->at(j);
97    if (phi->HasMergedIndex()) {
98      osr_values_->at(phi->merged_index())->set_incoming_value(phi);
99    }
100  }
101}
102
103}  // namespace internal
104}  // namespace v8
105