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/codegen/handler-table.h"
9#include "src/interpreter/bytecode-register.h"
10#include "src/interpreter/bytecodes.h"
11#include "src/objects/fixed-array.h"
12#include "src/zone/zone-containers.h"
13
14namespace v8 {
15namespace internal {
16
17template <typename T>
18class Handle;
19class HandlerTable;
20class Isolate;
21
22namespace interpreter {
23
24// A helper class for constructing exception handler tables for the interpreter.
25class V8_EXPORT_PRIVATE HandlerTableBuilder final {
26 public:
27  explicit HandlerTableBuilder(Zone* zone);
28  HandlerTableBuilder(const HandlerTableBuilder&) = delete;
29  HandlerTableBuilder& operator=(const HandlerTableBuilder&) = delete;
30
31  // Builds the actual handler table by copying the current values into a heap
32  // object. Any further mutations to the builder won't be reflected.
33  template <typename IsolateT>
34  Handle<ByteArray> ToHandlerTable(IsolateT* isolate);
35
36  // Creates a new handler table entry and returns a {hander_id} identifying the
37  // entry, so that it can be referenced by below setter functions.
38  int NewHandlerEntry();
39
40  // Setter functions that modify certain values within the handler table entry
41  // being referenced by the given {handler_id}. All values will be encoded by
42  // the resulting {HandlerTable} class when copied into the heap.
43  void SetTryRegionStart(int handler_id, size_t offset);
44  void SetTryRegionEnd(int handler_id, size_t offset);
45  void SetHandlerTarget(int handler_id, size_t offset);
46  void SetPrediction(int handler_id, HandlerTable::CatchPrediction prediction);
47  void SetContextRegister(int handler_id, Register reg);
48
49 private:
50  struct Entry {
51    size_t offset_start;   // Bytecode offset starting try-region.
52    size_t offset_end;     // Bytecode offset ending try-region.
53    size_t offset_target;  // Bytecode offset of handler target.
54    Register context;      // Register holding context for handler.
55                           // Optimistic prediction for handler.
56    HandlerTable::CatchPrediction catch_prediction_;
57  };
58
59  ZoneVector<Entry> entries_;
60};
61
62}  // namespace interpreter
63}  // namespace internal
64}  // namespace v8
65
66#endif  // V8_INTERPRETER_HANDLER_TABLE_BUILDER_H_
67