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.
HasOsrEntryAt(IterationStatement * statement)12 bool HOsrBuilder::HasOsrEntryAt(IterationStatement* statement) {
13 return statement->OsrEntryId() == builder_->current_info()->osr_ast_id();
14 }
15
16
BuildOsrLoopEntry(IterationStatement * statement)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
FinishGraph()87 void HOsrBuilder::FinishGraph() {
88 // do nothing for now.
89 }
90
91
FinishOsrValues()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
103