1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/jsanalyze.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,216 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +/* Definitions for javascript analysis. */
1.11 +
1.12 +#ifndef jsanalyze_h
1.13 +#define jsanalyze_h
1.14 +
1.15 +#include "jscompartment.h"
1.16 +
1.17 +namespace js {
1.18 +namespace analyze {
1.19 +
1.20 +class Bytecode;
1.21 +struct LifetimeVariable;
1.22 +class SlotValue;
1.23 +class SSAValue;
1.24 +struct SSAValueInfo;
1.25 +class SSAUseChain;
1.26 +
1.27 +// Common representation of slots between ScriptAnalysis, TypeScript, and in the
1.28 +// case of TotalSlots, Ion.
1.29 +static inline uint32_t ThisSlot() {
1.30 + return 0;
1.31 +}
1.32 +static inline uint32_t ArgSlot(uint32_t arg) {
1.33 + return 1 + arg;
1.34 +}
1.35 +static inline uint32_t LocalSlot(JSScript *script, uint32_t local) {
1.36 + return 1 + local +
1.37 + (script->functionNonDelazifying() ? script->functionNonDelazifying()->nargs() : 0);
1.38 +}
1.39 +static inline uint32_t TotalSlots(JSScript *script) {
1.40 + return LocalSlot(script, 0) + script->nfixed();
1.41 +}
1.42 +
1.43 +// Analysis information about a script. FIXME: At this point, the entire
1.44 +// purpose of this class is to compute JSScript::needsArgsObj, and to support
1.45 +// isReachable() in order for jsinfer.cpp:FindPreviousInnerInitializer to get
1.46 +// the previous opcode. For that purpose, it is completely overkill.
1.47 +class ScriptAnalysis
1.48 +{
1.49 + friend class Bytecode;
1.50 +
1.51 + JSScript *script_;
1.52 +
1.53 + Bytecode **codeArray;
1.54 +
1.55 + uint32_t numSlots;
1.56 +
1.57 + bool *escapedSlots;
1.58 +
1.59 +#ifdef DEBUG
1.60 + /* Whether the compartment was in debug mode when we performed the analysis. */
1.61 + bool originalDebugMode_: 1;
1.62 +#endif
1.63 +
1.64 + /* --------- Bytecode analysis --------- */
1.65 +
1.66 + bool canTrackVars:1;
1.67 + bool argumentsContentsObserved_:1;
1.68 +
1.69 + /* --------- Lifetime analysis --------- */
1.70 +
1.71 + LifetimeVariable *lifetimes;
1.72 +
1.73 + public:
1.74 + ScriptAnalysis(JSScript *script) {
1.75 + mozilla::PodZero(this);
1.76 + this->script_ = script;
1.77 +#ifdef DEBUG
1.78 + this->originalDebugMode_ = script_->compartment()->debugMode();
1.79 +#endif
1.80 + }
1.81 +
1.82 + MOZ_WARN_UNUSED_RESULT
1.83 + bool analyzeBytecode(JSContext *cx);
1.84 +
1.85 + bool isReachable(const jsbytecode *pc) { return maybeCode(pc); }
1.86 +
1.87 + private:
1.88 + MOZ_WARN_UNUSED_RESULT
1.89 + bool analyzeSSA(JSContext *cx);
1.90 + MOZ_WARN_UNUSED_RESULT
1.91 + bool analyzeLifetimes(JSContext *cx);
1.92 +
1.93 + /* Accessors for bytecode information. */
1.94 + Bytecode& getCode(uint32_t offset) {
1.95 + JS_ASSERT(offset < script_->length());
1.96 + JS_ASSERT(codeArray[offset]);
1.97 + return *codeArray[offset];
1.98 + }
1.99 + Bytecode& getCode(const jsbytecode *pc) { return getCode(script_->pcToOffset(pc)); }
1.100 +
1.101 + Bytecode* maybeCode(uint32_t offset) {
1.102 + JS_ASSERT(offset < script_->length());
1.103 + return codeArray[offset];
1.104 + }
1.105 + Bytecode* maybeCode(const jsbytecode *pc) { return maybeCode(script_->pcToOffset(pc)); }
1.106 +
1.107 + inline bool jumpTarget(uint32_t offset);
1.108 + inline bool jumpTarget(const jsbytecode *pc);
1.109 +
1.110 + inline const SSAValue &poppedValue(uint32_t offset, uint32_t which);
1.111 + inline const SSAValue &poppedValue(const jsbytecode *pc, uint32_t which);
1.112 +
1.113 + inline const SlotValue *newValues(uint32_t offset);
1.114 + inline const SlotValue *newValues(const jsbytecode *pc);
1.115 +
1.116 + inline bool trackUseChain(const SSAValue &v);
1.117 +
1.118 + /*
1.119 + * Get the use chain for an SSA value.
1.120 + */
1.121 + inline SSAUseChain *& useChain(const SSAValue &v);
1.122 +
1.123 +
1.124 + /* For a JSOP_CALL* op, get the pc of the corresponding JSOP_CALL/NEW/etc. */
1.125 + inline jsbytecode *getCallPC(jsbytecode *pc);
1.126 +
1.127 + /* Accessors for local variable information. */
1.128 +
1.129 + /*
1.130 + * Escaping slots include all slots that can be accessed in ways other than
1.131 + * through the corresponding LOCAL/ARG opcode. This includes all closed
1.132 + * slots in the script, all slots in scripts which use eval or are in debug
1.133 + * mode, and slots which are aliased by NAME or similar opcodes in the
1.134 + * containing script (which does not imply the variable is closed).
1.135 + */
1.136 + inline bool slotEscapes(uint32_t slot);
1.137 +
1.138 + /*
1.139 + * Whether we distinguish different writes of this variable while doing
1.140 + * SSA analysis. Escaping locals can be written in other scripts, and the
1.141 + * presence of NAME opcodes which could alias local variables or arguments
1.142 + * keeps us from tracking variable values at each point.
1.143 + */
1.144 + inline bool trackSlot(uint32_t slot);
1.145 +
1.146 + inline const LifetimeVariable & liveness(uint32_t slot);
1.147 +
1.148 + void printSSA(JSContext *cx);
1.149 + void printTypes(JSContext *cx);
1.150 +
1.151 + /* Bytecode helpers */
1.152 + MOZ_WARN_UNUSED_RESULT
1.153 + inline bool addJump(JSContext *cx, unsigned offset,
1.154 + unsigned *currentOffset, unsigned *forwardJump, unsigned *forwardLoop,
1.155 + unsigned stackDepth);
1.156 +
1.157 + /* Lifetime helpers */
1.158 + MOZ_WARN_UNUSED_RESULT
1.159 + inline bool addVariable(JSContext *cx, LifetimeVariable &var, unsigned offset,
1.160 + LifetimeVariable **&saved, unsigned &savedCount);
1.161 + MOZ_WARN_UNUSED_RESULT
1.162 + inline bool killVariable(JSContext *cx, LifetimeVariable &var, unsigned offset,
1.163 + LifetimeVariable **&saved, unsigned &savedCount);
1.164 + MOZ_WARN_UNUSED_RESULT
1.165 + inline bool extendVariable(JSContext *cx, LifetimeVariable &var, unsigned start, unsigned end);
1.166 +
1.167 + inline void ensureVariable(LifetimeVariable &var, unsigned until);
1.168 +
1.169 + /* SSA helpers */
1.170 + MOZ_WARN_UNUSED_RESULT
1.171 + bool makePhi(JSContext *cx, uint32_t slot, uint32_t offset, SSAValue *pv);
1.172 + MOZ_WARN_UNUSED_RESULT
1.173 + bool insertPhi(JSContext *cx, SSAValue &phi, const SSAValue &v);
1.174 + MOZ_WARN_UNUSED_RESULT
1.175 + bool mergeValue(JSContext *cx, uint32_t offset, const SSAValue &v, SlotValue *pv);
1.176 + MOZ_WARN_UNUSED_RESULT
1.177 + bool checkPendingValue(JSContext *cx, const SSAValue &v, uint32_t slot,
1.178 + Vector<SlotValue> *pending);
1.179 + MOZ_WARN_UNUSED_RESULT
1.180 + bool checkBranchTarget(JSContext *cx, uint32_t targetOffset, Vector<uint32_t> &branchTargets,
1.181 + SSAValueInfo *values, uint32_t stackDepth);
1.182 + MOZ_WARN_UNUSED_RESULT
1.183 + bool checkExceptionTarget(JSContext *cx, uint32_t catchOffset,
1.184 + Vector<uint32_t> &exceptionTargets);
1.185 + MOZ_WARN_UNUSED_RESULT
1.186 + bool mergeBranchTarget(JSContext *cx, SSAValueInfo &value, uint32_t slot,
1.187 + const Vector<uint32_t> &branchTargets, uint32_t currentOffset);
1.188 + MOZ_WARN_UNUSED_RESULT
1.189 + bool mergeExceptionTarget(JSContext *cx, const SSAValue &value, uint32_t slot,
1.190 + const Vector<uint32_t> &exceptionTargets);
1.191 + MOZ_WARN_UNUSED_RESULT
1.192 + bool mergeAllExceptionTargets(JSContext *cx, SSAValueInfo *values,
1.193 + const Vector<uint32_t> &exceptionTargets);
1.194 + MOZ_WARN_UNUSED_RESULT
1.195 + bool freezeNewValues(JSContext *cx, uint32_t offset);
1.196 +
1.197 + typedef Vector<SSAValue, 16> SeenVector;
1.198 + bool needsArgsObj(JSContext *cx, SeenVector &seen, const SSAValue &v);
1.199 + bool needsArgsObj(JSContext *cx, SeenVector &seen, SSAUseChain *use);
1.200 + bool needsArgsObj(JSContext *cx);
1.201 +
1.202 + public:
1.203 +#ifdef DEBUG
1.204 + void assertMatchingDebugMode();
1.205 + void assertMatchingStackDepthAtOffset(uint32_t offset, uint32_t stackDepth);
1.206 +#else
1.207 + void assertMatchingDebugMode() { }
1.208 + void assertMatchingStackDepthAtOffset(uint32_t offset, uint32_t stackDepth) { }
1.209 +#endif
1.210 +};
1.211 +
1.212 +#ifdef DEBUG
1.213 +void PrintBytecode(JSContext *cx, HandleScript script, jsbytecode *pc);
1.214 +#endif
1.215 +
1.216 +} /* namespace analyze */
1.217 +} /* namespace js */
1.218 +
1.219 +#endif /* jsanalyze_h */
