V8 API Reference, 7.2.502.16 (for Deno 0.2.4)
constants-table-builder.h
1 // Copyright 2018 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_BUILTINS_CONSTANTS_TABLE_BUILDER_H_
6 #define V8_BUILTINS_CONSTANTS_TABLE_BUILDER_H_
7 
8 #include "src/allocation.h"
9 #include "src/base/macros.h"
10 #include "src/handles.h"
11 #include "src/identity-map.h"
12 
13 namespace v8 {
14 namespace internal {
15 
16 class Isolate;
17 class Object;
18 
19 // Utility class to build the builtins constants table and store it on the root
20 // list. The constants table contains constants used by builtins, and is there
21 // to avoid directly embedding them into code objects, which would not be
22 // possible for off-heap (and thus immutable) code objects.
24  public:
25  explicit BuiltinsConstantsTableBuilder(Isolate* isolate);
26 
27  // Returns the index within the builtins constants table for the given
28  // object, possibly adding the object to the table. Objects are deduplicated.
29  uint32_t AddObject(Handle<Object> object);
30 
31  // Self-references during code generation start out by referencing a handle
32  // with a temporary dummy object. Once the final Code object exists, such
33  // entries in the constants map must be patched up.
34  void PatchSelfReference(Handle<Object> self_reference,
35  Handle<Code> code_object);
36 
37  // Should be called after all affected code (e.g. builtins and bytecode
38  // handlers) has been generated.
39  void Finalize();
40 
41  private:
42  Isolate* isolate_;
43 
44  // Maps objects to corresponding indices within the constants list.
46  ConstantsMap map_;
47 
48  DISALLOW_COPY_AND_ASSIGN(BuiltinsConstantsTableBuilder)
49 };
50 
51 } // namespace internal
52 } // namespace v8
53 
54 #endif // V8_BUILTINS_CONSTANTS_TABLE_BUILDER_H_
Definition: libplatform.h:13