1// Copyright 2016 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_INTERPRETER_HANDLER_TABLE_BUILDER_H_
6#define V8_INTERPRETER_HANDLER_TABLE_BUILDER_H_
7
8#include "src/interpreter/bytecode-register.h"
9#include "src/interpreter/bytecodes.h"
10#include "src/zone/zone-containers.h"
11
12namespace v8 {
13namespace internal {
14
15template <typename T>
16class Handle;
17class HandlerTable;
18class Isolate;
19
20namespace interpreter {
21
22// A helper class for constructing exception handler tables for the interpreter.
23class V8_EXPORT_PRIVATE HandlerTableBuilder final BASE_EMBEDDED {
24 public:
25  explicit HandlerTableBuilder(Zone* zone);
26
27  // Builds the actual handler table by copying the current values into a heap
28  // object. Any further mutations to the builder won't be reflected.
29  Handle<HandlerTable> ToHandlerTable(Isolate* isolate);
30
31  // Creates a new handler table entry and returns a {hander_id} identifying the
32  // entry, so that it can be referenced by below setter functions.
33  int NewHandlerEntry();
34
35  // Setter functions that modify certain values within the handler table entry
36  // being referenced by the given {handler_id}. All values will be encoded by
37  // the resulting {HandlerTable} class when copied into the heap.
38  void SetTryRegionStart(int handler_id, size_t offset);
39  void SetTryRegionEnd(int handler_id, size_t offset);
40  void SetHandlerTarget(int handler_id, size_t offset);
41  void SetPrediction(int handler_id, HandlerTable::CatchPrediction prediction);
42  void SetContextRegister(int handler_id, Register reg);
43
44 private:
45  struct Entry {
46    size_t offset_start;   // Bytecode offset starting try-region.
47    size_t offset_end;     // Bytecode offset ending try-region.
48    size_t offset_target;  // Bytecode offset of handler target.
49    Register context;      // Register holding context for handler.
50                           // Optimistic prediction for handler.
51    HandlerTable::CatchPrediction catch_prediction_;
52  };
53
54  ZoneVector<Entry> entries_;
55
56  DISALLOW_COPY_AND_ASSIGN(HandlerTableBuilder);
57};
58
59}  // namespace interpreter
60}  // namespace internal
61}  // namespace v8
62
63#endif  // V8_INTERPRETER_HANDLER_TABLE_BUILDER_H_
64