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js/src/jsanalyze.h@b8a032363ba2 (annotated)

js/src/jsanalyze.h

Thu, 22 Jan 2015 13:21:57 +0100

author
Michael Schloh von Bennewitz <michael@schloh.com>
date
Thu, 22 Jan 2015 13:21:57 +0100
branch
TOR_BUG_9701
changeset 15
b8a032363ba2
permissions
-rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

michael@0 1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0 2 * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0 3 * This Source Code Form is subject to the terms of the Mozilla Public
michael@0 4 * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0 6
michael@0 7 /* Definitions for javascript analysis. */
michael@0 8
michael@0 9 #ifndef jsanalyze_h
michael@0 10 #define jsanalyze_h
michael@0 11
michael@0 12 #include "jscompartment.h"
michael@0 13
michael@0 14 namespace js {
michael@0 15 namespace analyze {
michael@0 16
michael@0 17 class Bytecode;
michael@0 18 struct LifetimeVariable;
michael@0 19 class SlotValue;
michael@0 20 class SSAValue;
michael@0 21 struct SSAValueInfo;
michael@0 22 class SSAUseChain;
michael@0 23
michael@0 24 // Common representation of slots between ScriptAnalysis, TypeScript, and in the
michael@0 25 // case of TotalSlots, Ion.
michael@0 26 static inline uint32_t ThisSlot() {
michael@0 27 return 0;
michael@0 28 }
michael@0 29 static inline uint32_t ArgSlot(uint32_t arg) {
michael@0 30 return 1 + arg;
michael@0 31 }
michael@0 32 static inline uint32_t LocalSlot(JSScript *script, uint32_t local) {
michael@0 33 return 1 + local +
michael@0 34 (script->functionNonDelazifying() ? script->functionNonDelazifying()->nargs() : 0);
michael@0 35 }
michael@0 36 static inline uint32_t TotalSlots(JSScript *script) {
michael@0 37 return LocalSlot(script, 0) + script->nfixed();
michael@0 38 }
michael@0 39
michael@0 40 // Analysis information about a script. FIXME: At this point, the entire
michael@0 41 // purpose of this class is to compute JSScript::needsArgsObj, and to support
michael@0 42 // isReachable() in order for jsinfer.cpp:FindPreviousInnerInitializer to get
michael@0 43 // the previous opcode. For that purpose, it is completely overkill.
michael@0 44 class ScriptAnalysis
michael@0 45 {
michael@0 46 friend class Bytecode;
michael@0 47
michael@0 48 JSScript *script_;
michael@0 49
michael@0 50 Bytecode **codeArray;
michael@0 51
michael@0 52 uint32_t numSlots;
michael@0 53
michael@0 54 bool *escapedSlots;
michael@0 55
michael@0 56 #ifdef DEBUG
michael@0 57 /* Whether the compartment was in debug mode when we performed the analysis. */
michael@0 58 bool originalDebugMode_: 1;
michael@0 59 #endif
michael@0 60
michael@0 61 /* --------- Bytecode analysis --------- */
michael@0 62
michael@0 63 bool canTrackVars:1;
michael@0 64 bool argumentsContentsObserved_:1;
michael@0 65
michael@0 66 /* --------- Lifetime analysis --------- */
michael@0 67
michael@0 68 LifetimeVariable *lifetimes;
michael@0 69
michael@0 70 public:
michael@0 71 ScriptAnalysis(JSScript *script) {
michael@0 72 mozilla::PodZero(this);
michael@0 73 this->script_ = script;
michael@0 74 #ifdef DEBUG
michael@0 75 this->originalDebugMode_ = script_->compartment()->debugMode();
michael@0 76 #endif
michael@0 77 }
michael@0 78
michael@0 79 MOZ_WARN_UNUSED_RESULT
michael@0 80 bool analyzeBytecode(JSContext *cx);
michael@0 81
michael@0 82 bool isReachable(const jsbytecode *pc) { return maybeCode(pc); }
michael@0 83
michael@0 84 private:
michael@0 85 MOZ_WARN_UNUSED_RESULT
michael@0 86 bool analyzeSSA(JSContext *cx);
michael@0 87 MOZ_WARN_UNUSED_RESULT
michael@0 88 bool analyzeLifetimes(JSContext *cx);
michael@0 89
michael@0 90 /* Accessors for bytecode information. */
michael@0 91 Bytecode& getCode(uint32_t offset) {
michael@0 92 JS_ASSERT(offset < script_->length());
michael@0 93 JS_ASSERT(codeArray[offset]);
michael@0 94 return *codeArray[offset];
michael@0 95 }
michael@0 96 Bytecode& getCode(const jsbytecode *pc) { return getCode(script_->pcToOffset(pc)); }
michael@0 97
michael@0 98 Bytecode* maybeCode(uint32_t offset) {
michael@0 99 JS_ASSERT(offset < script_->length());
michael@0 100 return codeArray[offset];
michael@0 101 }
michael@0 102 Bytecode* maybeCode(const jsbytecode *pc) { return maybeCode(script_->pcToOffset(pc)); }
michael@0 103
michael@0 104 inline bool jumpTarget(uint32_t offset);
michael@0 105 inline bool jumpTarget(const jsbytecode *pc);
michael@0 106
michael@0 107 inline const SSAValue &poppedValue(uint32_t offset, uint32_t which);
michael@0 108 inline const SSAValue &poppedValue(const jsbytecode *pc, uint32_t which);
michael@0 109
michael@0 110 inline const SlotValue *newValues(uint32_t offset);
michael@0 111 inline const SlotValue *newValues(const jsbytecode *pc);
michael@0 112
michael@0 113 inline bool trackUseChain(const SSAValue &v);
michael@0 114
michael@0 115 /*
michael@0 116 * Get the use chain for an SSA value.
michael@0 117 */
michael@0 118 inline SSAUseChain *& useChain(const SSAValue &v);
michael@0 119
michael@0 120
michael@0 121 /* For a JSOP_CALL* op, get the pc of the corresponding JSOP_CALL/NEW/etc. */
michael@0 122 inline jsbytecode *getCallPC(jsbytecode *pc);
michael@0 123
michael@0 124 /* Accessors for local variable information. */
michael@0 125
michael@0 126 /*
michael@0 127 * Escaping slots include all slots that can be accessed in ways other than
michael@0 128 * through the corresponding LOCAL/ARG opcode. This includes all closed
michael@0 129 * slots in the script, all slots in scripts which use eval or are in debug
michael@0 130 * mode, and slots which are aliased by NAME or similar opcodes in the
michael@0 131 * containing script (which does not imply the variable is closed).
michael@0 132 */
michael@0 133 inline bool slotEscapes(uint32_t slot);
michael@0 134
michael@0 135 /*
michael@0 136 * Whether we distinguish different writes of this variable while doing
michael@0 137 * SSA analysis. Escaping locals can be written in other scripts, and the
michael@0 138 * presence of NAME opcodes which could alias local variables or arguments
michael@0 139 * keeps us from tracking variable values at each point.
michael@0 140 */
michael@0 141 inline bool trackSlot(uint32_t slot);
michael@0 142
michael@0 143 inline const LifetimeVariable & liveness(uint32_t slot);
michael@0 144
michael@0 145 void printSSA(JSContext *cx);
michael@0 146 void printTypes(JSContext *cx);
michael@0 147
michael@0 148 /* Bytecode helpers */
michael@0 149 MOZ_WARN_UNUSED_RESULT
michael@0 150 inline bool addJump(JSContext *cx, unsigned offset,
michael@0 151 unsigned *currentOffset, unsigned *forwardJump, unsigned *forwardLoop,
michael@0 152 unsigned stackDepth);
michael@0 153
michael@0 154 /* Lifetime helpers */
michael@0 155 MOZ_WARN_UNUSED_RESULT
michael@0 156 inline bool addVariable(JSContext *cx, LifetimeVariable &var, unsigned offset,
michael@0 157 LifetimeVariable **&saved, unsigned &savedCount);
michael@0 158 MOZ_WARN_UNUSED_RESULT
michael@0 159 inline bool killVariable(JSContext *cx, LifetimeVariable &var, unsigned offset,
michael@0 160 LifetimeVariable **&saved, unsigned &savedCount);
michael@0 161 MOZ_WARN_UNUSED_RESULT
michael@0 162 inline bool extendVariable(JSContext *cx, LifetimeVariable &var, unsigned start, unsigned end);
michael@0 163
michael@0 164 inline void ensureVariable(LifetimeVariable &var, unsigned until);
michael@0 165
michael@0 166 /* SSA helpers */
michael@0 167 MOZ_WARN_UNUSED_RESULT
michael@0 168 bool makePhi(JSContext *cx, uint32_t slot, uint32_t offset, SSAValue *pv);
michael@0 169 MOZ_WARN_UNUSED_RESULT
michael@0 170 bool insertPhi(JSContext *cx, SSAValue &phi, const SSAValue &v);
michael@0 171 MOZ_WARN_UNUSED_RESULT
michael@0 172 bool mergeValue(JSContext *cx, uint32_t offset, const SSAValue &v, SlotValue *pv);
michael@0 173 MOZ_WARN_UNUSED_RESULT
michael@0 174 bool checkPendingValue(JSContext *cx, const SSAValue &v, uint32_t slot,
michael@0 175 Vector<SlotValue> *pending);
michael@0 176 MOZ_WARN_UNUSED_RESULT
michael@0 177 bool checkBranchTarget(JSContext *cx, uint32_t targetOffset, Vector<uint32_t> &branchTargets,
michael@0 178 SSAValueInfo *values, uint32_t stackDepth);
michael@0 179 MOZ_WARN_UNUSED_RESULT
michael@0 180 bool checkExceptionTarget(JSContext *cx, uint32_t catchOffset,
michael@0 181 Vector<uint32_t> &exceptionTargets);
michael@0 182 MOZ_WARN_UNUSED_RESULT
michael@0 183 bool mergeBranchTarget(JSContext *cx, SSAValueInfo &value, uint32_t slot,
michael@0 184 const Vector<uint32_t> &branchTargets, uint32_t currentOffset);
michael@0 185 MOZ_WARN_UNUSED_RESULT
michael@0 186 bool mergeExceptionTarget(JSContext *cx, const SSAValue &value, uint32_t slot,
michael@0 187 const Vector<uint32_t> &exceptionTargets);
michael@0 188 MOZ_WARN_UNUSED_RESULT
michael@0 189 bool mergeAllExceptionTargets(JSContext *cx, SSAValueInfo *values,
michael@0 190 const Vector<uint32_t> &exceptionTargets);
michael@0 191 MOZ_WARN_UNUSED_RESULT
michael@0 192 bool freezeNewValues(JSContext *cx, uint32_t offset);
michael@0 193
michael@0 194 typedef Vector<SSAValue, 16> SeenVector;
michael@0 195 bool needsArgsObj(JSContext *cx, SeenVector &seen, const SSAValue &v);
michael@0 196 bool needsArgsObj(JSContext *cx, SeenVector &seen, SSAUseChain *use);
michael@0 197 bool needsArgsObj(JSContext *cx);
michael@0 198
michael@0 199 public:
michael@0 200 #ifdef DEBUG
michael@0 201 void assertMatchingDebugMode();
michael@0 202 void assertMatchingStackDepthAtOffset(uint32_t offset, uint32_t stackDepth);
michael@0 203 #else
michael@0 204 void assertMatchingDebugMode() { }
michael@0 205 void assertMatchingStackDepthAtOffset(uint32_t offset, uint32_t stackDepth) { }
michael@0 206 #endif
michael@0 207 };
michael@0 208
michael@0 209 #ifdef DEBUG
michael@0 210 void PrintBytecode(JSContext *cx, HandleScript script, jsbytecode *pc);
michael@0 211 #endif
michael@0 212
michael@0 213 } /* namespace analyze */
michael@0 214 } /* namespace js */
michael@0 215
michael@0 216 #endif /* jsanalyze_h */

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