The Tor Browser / file comparison
comparison: js/src/jsanalyze.h
js/src/jsanalyze.h
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- TOR_BUG_3246
- changeset 7
- 129ffea94266
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| -1:000000000000 | 0:ffab974a9dc1 |
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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 /* Definitions for javascript analysis. */ | |
| 8 | |
| 9 #ifndef jsanalyze_h | |
| 10 #define jsanalyze_h | |
| 11 | |
| 12 #include "jscompartment.h" | |
| 13 | |
| 14 namespace js { | |
| 15 namespace analyze { | |
| 16 | |
| 17 class Bytecode; | |
| 18 struct LifetimeVariable; | |
| 19 class SlotValue; | |
| 20 class SSAValue; | |
| 21 struct SSAValueInfo; | |
| 22 class SSAUseChain; | |
| 23 | |
| 24 // Common representation of slots between ScriptAnalysis, TypeScript, and in the | |
| 25 // case of TotalSlots, Ion. | |
| 26 static inline uint32_t ThisSlot() { | |
| 27 return 0; | |
| 28 } | |
| 29 static inline uint32_t ArgSlot(uint32_t arg) { | |
| 30 return 1 + arg; | |
| 31 } | |
| 32 static inline uint32_t LocalSlot(JSScript *script, uint32_t local) { | |
| 33 return 1 + local + | |
| 34 (script->functionNonDelazifying() ? script->functionNonDelazifying()->nargs() : 0); | |
| 35 } | |
| 36 static inline uint32_t TotalSlots(JSScript *script) { | |
| 37 return LocalSlot(script, 0) + script->nfixed(); | |
| 38 } | |
| 39 | |
| 40 // Analysis information about a script. FIXME: At this point, the entire | |
| 41 // purpose of this class is to compute JSScript::needsArgsObj, and to support | |
| 42 // isReachable() in order for jsinfer.cpp:FindPreviousInnerInitializer to get | |
| 43 // the previous opcode. For that purpose, it is completely overkill. | |
| 44 class ScriptAnalysis | |
| 45 { | |
| 46 friend class Bytecode; | |
| 47 | |
| 48 JSScript *script_; | |
| 49 | |
| 50 Bytecode **codeArray; | |
| 51 | |
| 52 uint32_t numSlots; | |
| 53 | |
| 54 bool *escapedSlots; | |
| 55 | |
| 56 #ifdef DEBUG | |
| 57 /* Whether the compartment was in debug mode when we performed the analysis. */ | |
| 58 bool originalDebugMode_: 1; | |
| 59 #endif | |
| 60 | |
| 61 /* --------- Bytecode analysis --------- */ | |
| 62 | |
| 63 bool canTrackVars:1; | |
| 64 bool argumentsContentsObserved_:1; | |
| 65 | |
| 66 /* --------- Lifetime analysis --------- */ | |
| 67 | |
| 68 LifetimeVariable *lifetimes; | |
| 69 | |
| 70 public: | |
| 71 ScriptAnalysis(JSScript *script) { | |
| 72 mozilla::PodZero(this); | |
| 73 this->script_ = script; | |
| 74 #ifdef DEBUG | |
| 75 this->originalDebugMode_ = script_->compartment()->debugMode(); | |
| 76 #endif | |
| 77 } | |
| 78 | |
| 79 MOZ_WARN_UNUSED_RESULT | |
| 80 bool analyzeBytecode(JSContext *cx); | |
| 81 | |
| 82 bool isReachable(const jsbytecode *pc) { return maybeCode(pc); } | |
| 83 | |
| 84 private: | |
| 85 MOZ_WARN_UNUSED_RESULT | |
| 86 bool analyzeSSA(JSContext *cx); | |
| 87 MOZ_WARN_UNUSED_RESULT | |
| 88 bool analyzeLifetimes(JSContext *cx); | |
| 89 | |
| 90 /* Accessors for bytecode information. */ | |
| 91 Bytecode& getCode(uint32_t offset) { | |
| 92 JS_ASSERT(offset < script_->length()); | |
| 93 JS_ASSERT(codeArray[offset]); | |
| 94 return *codeArray[offset]; | |
| 95 } | |
| 96 Bytecode& getCode(const jsbytecode *pc) { return getCode(script_->pcToOffset(pc)); } | |
| 97 | |
| 98 Bytecode* maybeCode(uint32_t offset) { | |
| 99 JS_ASSERT(offset < script_->length()); | |
| 100 return codeArray[offset]; | |
| 101 } | |
| 102 Bytecode* maybeCode(const jsbytecode *pc) { return maybeCode(script_->pcToOffset(pc)); } | |
| 103 | |
| 104 inline bool jumpTarget(uint32_t offset); | |
| 105 inline bool jumpTarget(const jsbytecode *pc); | |
| 106 | |
| 107 inline const SSAValue &poppedValue(uint32_t offset, uint32_t which); | |
| 108 inline const SSAValue &poppedValue(const jsbytecode *pc, uint32_t which); | |
| 109 | |
| 110 inline const SlotValue *newValues(uint32_t offset); | |
| 111 inline const SlotValue *newValues(const jsbytecode *pc); | |
| 112 | |
| 113 inline bool trackUseChain(const SSAValue &v); | |
| 114 | |
| 115 /* | |
| 116 * Get the use chain for an SSA value. | |
| 117 */ | |
| 118 inline SSAUseChain *& useChain(const SSAValue &v); | |
| 119 | |
| 120 | |
| 121 /* For a JSOP_CALL* op, get the pc of the corresponding JSOP_CALL/NEW/etc. */ | |
| 122 inline jsbytecode *getCallPC(jsbytecode *pc); | |
| 123 | |
| 124 /* Accessors for local variable information. */ | |
| 125 | |
| 126 /* | |
| 127 * Escaping slots include all slots that can be accessed in ways other than | |
| 128 * through the corresponding LOCAL/ARG opcode. This includes all closed | |
| 129 * slots in the script, all slots in scripts which use eval or are in debug | |
| 130 * mode, and slots which are aliased by NAME or similar opcodes in the | |
| 131 * containing script (which does not imply the variable is closed). | |
| 132 */ | |
| 133 inline bool slotEscapes(uint32_t slot); | |
| 134 | |
| 135 /* | |
| 136 * Whether we distinguish different writes of this variable while doing | |
| 137 * SSA analysis. Escaping locals can be written in other scripts, and the | |
| 138 * presence of NAME opcodes which could alias local variables or arguments | |
| 139 * keeps us from tracking variable values at each point. | |
| 140 */ | |
| 141 inline bool trackSlot(uint32_t slot); | |
| 142 | |
| 143 inline const LifetimeVariable & liveness(uint32_t slot); | |
| 144 | |
| 145 void printSSA(JSContext *cx); | |
| 146 void printTypes(JSContext *cx); | |
| 147 | |
| 148 /* Bytecode helpers */ | |
| 149 MOZ_WARN_UNUSED_RESULT | |
| 150 inline bool addJump(JSContext *cx, unsigned offset, | |
| 151 unsigned *currentOffset, unsigned *forwardJump, unsigned *forwardLoop, | |
| 152 unsigned stackDepth); | |
| 153 | |
| 154 /* Lifetime helpers */ | |
| 155 MOZ_WARN_UNUSED_RESULT | |
| 156 inline bool addVariable(JSContext *cx, LifetimeVariable &var, unsigned offset, | |
| 157 LifetimeVariable **&saved, unsigned &savedCount); | |
| 158 MOZ_WARN_UNUSED_RESULT | |
| 159 inline bool killVariable(JSContext *cx, LifetimeVariable &var, unsigned offset, | |
| 160 LifetimeVariable **&saved, unsigned &savedCount); | |
| 161 MOZ_WARN_UNUSED_RESULT | |
| 162 inline bool extendVariable(JSContext *cx, LifetimeVariable &var, unsigned start, unsigned end); | |
| 163 | |
| 164 inline void ensureVariable(LifetimeVariable &var, unsigned until); | |
| 165 | |
| 166 /* SSA helpers */ | |
| 167 MOZ_WARN_UNUSED_RESULT | |
| 168 bool makePhi(JSContext *cx, uint32_t slot, uint32_t offset, SSAValue *pv); | |
| 169 MOZ_WARN_UNUSED_RESULT | |
| 170 bool insertPhi(JSContext *cx, SSAValue &phi, const SSAValue &v); | |
| 171 MOZ_WARN_UNUSED_RESULT | |
| 172 bool mergeValue(JSContext *cx, uint32_t offset, const SSAValue &v, SlotValue *pv); | |
| 173 MOZ_WARN_UNUSED_RESULT | |
| 174 bool checkPendingValue(JSContext *cx, const SSAValue &v, uint32_t slot, | |
| 175 Vector<SlotValue> *pending); | |
| 176 MOZ_WARN_UNUSED_RESULT | |
| 177 bool checkBranchTarget(JSContext *cx, uint32_t targetOffset, Vector<uint32_t> &branchTargets, | |
| 178 SSAValueInfo *values, uint32_t stackDepth); | |
| 179 MOZ_WARN_UNUSED_RESULT | |
| 180 bool checkExceptionTarget(JSContext *cx, uint32_t catchOffset, | |
| 181 Vector<uint32_t> &exceptionTargets); | |
| 182 MOZ_WARN_UNUSED_RESULT | |
| 183 bool mergeBranchTarget(JSContext *cx, SSAValueInfo &value, uint32_t slot, | |
| 184 const Vector<uint32_t> &branchTargets, uint32_t currentOffset); | |
| 185 MOZ_WARN_UNUSED_RESULT | |
| 186 bool mergeExceptionTarget(JSContext *cx, const SSAValue &value, uint32_t slot, | |
| 187 const Vector<uint32_t> &exceptionTargets); | |
| 188 MOZ_WARN_UNUSED_RESULT | |
| 189 bool mergeAllExceptionTargets(JSContext *cx, SSAValueInfo *values, | |
| 190 const Vector<uint32_t> &exceptionTargets); | |
| 191 MOZ_WARN_UNUSED_RESULT | |
| 192 bool freezeNewValues(JSContext *cx, uint32_t offset); | |
| 193 | |
| 194 typedef Vector<SSAValue, 16> SeenVector; | |
| 195 bool needsArgsObj(JSContext *cx, SeenVector &seen, const SSAValue &v); | |
| 196 bool needsArgsObj(JSContext *cx, SeenVector &seen, SSAUseChain *use); | |
| 197 bool needsArgsObj(JSContext *cx); | |
| 198 | |
| 199 public: | |
| 200 #ifdef DEBUG | |
| 201 void assertMatchingDebugMode(); | |
| 202 void assertMatchingStackDepthAtOffset(uint32_t offset, uint32_t stackDepth); | |
| 203 #else | |
| 204 void assertMatchingDebugMode() { } | |
| 205 void assertMatchingStackDepthAtOffset(uint32_t offset, uint32_t stackDepth) { } | |
| 206 #endif | |
| 207 }; | |
| 208 | |
| 209 #ifdef DEBUG | |
| 210 void PrintBytecode(JSContext *cx, HandleScript script, jsbytecode *pc); | |
| 211 #endif | |
| 212 | |
| 213 } /* namespace analyze */ | |
| 214 } /* namespace js */ | |
| 215 | |
| 216 #endif /* jsanalyze_h */ |
