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#ifndef V8_ALLOCATION_SITE_SCOPES_H_
6#define V8_ALLOCATION_SITE_SCOPES_H_
7
8#include "src/ast.h"
9#include "src/handles.h"
10#include "src/objects.h"
11#include "src/zone.h"
12
13namespace v8 {
14namespace internal {
15
16
17// AllocationSiteContext is the base class for walking and copying a nested
18// boilerplate with AllocationSite and AllocationMemento support.
19class AllocationSiteContext {
20 public:
21  explicit AllocationSiteContext(Isolate* isolate) {
22    isolate_ = isolate;
23  }
24
25  Handle<AllocationSite> top() { return top_; }
26  Handle<AllocationSite> current() { return current_; }
27
28  bool ShouldCreateMemento(Handle<JSObject> object) { return false; }
29
30  Isolate* isolate() { return isolate_; }
31
32 protected:
33  void update_current_site(AllocationSite* site) {
34    *(current_.location()) = site;
35  }
36
37  void InitializeTraversal(Handle<AllocationSite> site) {
38    top_ = site;
39    current_ = Handle<AllocationSite>(*top_, isolate());
40  }
41
42 private:
43  Isolate* isolate_;
44  Handle<AllocationSite> top_;
45  Handle<AllocationSite> current_;
46};
47
48
49// AllocationSiteCreationContext aids in the creation of AllocationSites to
50// accompany object literals.
51class AllocationSiteCreationContext : public AllocationSiteContext {
52 public:
53  explicit AllocationSiteCreationContext(Isolate* isolate)
54      : AllocationSiteContext(isolate) { }
55
56  Handle<AllocationSite> EnterNewScope();
57  void ExitScope(Handle<AllocationSite> site, Handle<JSObject> object);
58};
59
60
61// AllocationSiteUsageContext aids in the creation of AllocationMementos placed
62// behind some/all components of a copied object literal.
63class AllocationSiteUsageContext : public AllocationSiteContext {
64 public:
65  AllocationSiteUsageContext(Isolate* isolate, Handle<AllocationSite> site,
66                             bool activated)
67      : AllocationSiteContext(isolate),
68        top_site_(site),
69        activated_(activated) { }
70
71  inline Handle<AllocationSite> EnterNewScope() {
72    if (top().is_null()) {
73      InitializeTraversal(top_site_);
74    } else {
75      // Advance current site
76      Object* nested_site = current()->nested_site();
77      // Something is wrong if we advance to the end of the list here.
78      DCHECK(nested_site->IsAllocationSite());
79      update_current_site(AllocationSite::cast(nested_site));
80    }
81    return Handle<AllocationSite>(*current(), isolate());
82  }
83
84  inline void ExitScope(Handle<AllocationSite> scope_site,
85                        Handle<JSObject> object) {
86    // This assert ensures that we are pointing at the right sub-object in a
87    // recursive walk of a nested literal.
88    DCHECK(object.is_null() || *object == scope_site->transition_info());
89  }
90
91  bool ShouldCreateMemento(Handle<JSObject> object);
92
93 private:
94  Handle<AllocationSite> top_site_;
95  bool activated_;
96};
97
98
99} }  // namespace v8::internal
100
101#endif  // V8_ALLOCATION_SITE_SCOPES_H_
102