1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef frontend_TryEmitter_h
#define frontend_TryEmitter_h
#include "mozilla/Attributes.h"
#include "mozilla/Maybe.h"
#include <stddef.h>
#include <stdint.h>
#include "frontend/BytecodeControlStructures.h"
#include "frontend/JumpList.h"
#include "frontend/TDZCheckCache.h"
namespace js {
namespace frontend {
struct BytecodeEmitter;
class MOZ_STACK_CLASS TryEmitter
{
public:
enum Kind {
TryCatch,
TryCatchFinally,
TryFinally
};
enum ShouldUseRetVal {
UseRetVal,
DontUseRetVal
};
enum ShouldUseControl {
UseControl,
DontUseControl,
};
private:
BytecodeEmitter* bce_;
Kind kind_;
ShouldUseRetVal retValKind_;
// Track jumps-over-catches and gosubs-to-finally for later fixup.
//
// When a finally block is active, non-local jumps (including
// jumps-over-catches) result in a GOSUB being written into the bytecode
// stream and fixed-up later.
//
// If ShouldUseControl is DontUseControl, all that handling is skipped.
// DontUseControl is used by yield* and the internal try-catch around
// IteratorClose. These internal uses must:
// * have only one catch block
// * have no catch guard
// * have JSOP_GOTO at the end of catch-block
// * have no non-local-jump
// * don't use finally block for normal completion of try-block and
// catch-block
//
// Additionally, a finally block may be emitted when ShouldUseControl is
// DontUseControl, even if the kind is not TryCatchFinally or TryFinally,
// because GOSUBs are not emitted. This internal use shares the
// requirements as above.
Maybe<TryFinallyControl> controlInfo_;
int depth_;
unsigned noteIndex_;
ptrdiff_t tryStart_;
JumpList catchAndFinallyJump_;
JumpTarget tryEnd_;
JumpTarget finallyStart_;
enum State {
Start,
Try,
TryEnd,
Catch,
CatchEnd,
Finally,
FinallyEnd,
End
};
State state_;
bool hasCatch() const {
return kind_ == TryCatch || kind_ == TryCatchFinally;
}
bool hasFinally() const {
return kind_ == TryCatchFinally || kind_ == TryFinally;
}
public:
TryEmitter(BytecodeEmitter* bce, Kind kind,
ShouldUseRetVal retValKind = UseRetVal, ShouldUseControl controlKind = UseControl);
MOZ_MUST_USE bool emitJumpOverCatchAndFinally();
MOZ_MUST_USE bool emitTry();
MOZ_MUST_USE bool emitCatch();
MOZ_MUST_USE bool emitFinally(const mozilla::Maybe<uint32_t>& finallyPos = mozilla::Nothing());
MOZ_MUST_USE bool emitEnd();
private:
MOZ_MUST_USE bool emitTryEnd();
MOZ_MUST_USE bool emitCatchEnd(bool hasNext);
MOZ_MUST_USE bool emitFinallyEnd();
};
} /* namespace frontend */
} /* namespace js */
#endif /* frontend_TryEmitter_h */
|
