js/src/jit/BytecodeAnalysis.h

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1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 * vim: set ts=8 sts=4 et sw=4 tw=99:
3 * This Source Code Form is subject to the terms of the Mozilla Public
4 * License, v. 2.0. If a copy of the MPL was not distributed with this
5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
6
7 #ifndef jit_BytecodeAnalysis_h
8 #define jit_BytecodeAnalysis_h
9
10 #include "jsscript.h"
11 #include "jit/IonAllocPolicy.h"
12 #include "js/Vector.h"
13
14 namespace js {
15 namespace jit {
16
17 // Basic information about bytecodes in the script. Used to help baseline compilation.
18 struct BytecodeInfo
19 {
20 static const uint16_t MAX_STACK_DEPTH = 0xffffU;
21 uint16_t stackDepth;
22 bool initialized : 1;
23 bool jumpTarget : 1;
24 bool jumpFallthrough : 1;
25 bool fallthrough : 1;
26
27 // If true, this is a JSOP_LOOPENTRY op inside a catch or finally block.
28 bool loopEntryInCatchOrFinally : 1;
29
30 void init(unsigned depth) {
31 JS_ASSERT(depth <= MAX_STACK_DEPTH);
32 JS_ASSERT_IF(initialized, stackDepth == depth);
33 initialized = true;
34 stackDepth = depth;
35 }
36 };
37
38 class BytecodeAnalysis
39 {
40 JSScript *script_;
41 Vector<BytecodeInfo, 0, IonAllocPolicy> infos_;
42
43 bool usesScopeChain_;
44 bool hasTryFinally_;
45 bool hasSetArg_;
46
47 public:
48 explicit BytecodeAnalysis(TempAllocator &alloc, JSScript *script);
49
50 bool init(TempAllocator &alloc, GSNCache &gsn);
51
52 BytecodeInfo &info(jsbytecode *pc) {
53 JS_ASSERT(infos_[script_->pcToOffset(pc)].initialized);
54 return infos_[script_->pcToOffset(pc)];
55 }
56
57 BytecodeInfo *maybeInfo(jsbytecode *pc) {
58 if (infos_[script_->pcToOffset(pc)].initialized)
59 return &infos_[script_->pcToOffset(pc)];
60 return nullptr;
61 }
62
63 bool usesScopeChain() const {
64 return usesScopeChain_;
65 }
66
67 bool hasTryFinally() const {
68 return hasTryFinally_;
69 }
70
71 bool hasSetArg() const {
72 return hasSetArg_;
73 }
74 };
75
76
77 } // namespace jit
78 } // namespace js
79
80 #endif /* jit_BytecodeAnalysis_h */

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