1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/jit/CompileInfo.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,340 @@
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 +#ifndef jit_CompileInfo_h
1.11 +#define jit_CompileInfo_h
1.12 +
1.13 +#include "jsfun.h"
1.14 +
1.15 +#include "jit/Registers.h"
1.16 +#include "vm/ScopeObject.h"
1.17 +
1.18 +namespace js {
1.19 +namespace jit {
1.20 +
1.21 +inline unsigned
1.22 +StartArgSlot(JSScript *script)
1.23 +{
1.24 + // Reserved slots:
1.25 + // Slot 0: Scope chain.
1.26 + // Slot 1: Return value.
1.27 +
1.28 + // When needed:
1.29 + // Slot 2: Argumentsobject.
1.30 +
1.31 + // Note: when updating this, please also update the assert in SnapshotWriter::startFrame
1.32 + return 2 + (script->argumentsHasVarBinding() ? 1 : 0);
1.33 +}
1.34 +
1.35 +inline unsigned
1.36 +CountArgSlots(JSScript *script, JSFunction *fun)
1.37 +{
1.38 + // Slot x + 0: This value.
1.39 + // Slot x + 1: Argument 1.
1.40 + // ...
1.41 + // Slot x + n: Argument n.
1.42 +
1.43 + // Note: when updating this, please also update the assert in SnapshotWriter::startFrame
1.44 + return StartArgSlot(script) + (fun ? fun->nargs() + 1 : 0);
1.45 +}
1.46 +
1.47 +// Contains information about the compilation source for IR being generated.
1.48 +class CompileInfo
1.49 +{
1.50 + public:
1.51 + CompileInfo(JSScript *script, JSFunction *fun, jsbytecode *osrPc, bool constructing,
1.52 + ExecutionMode executionMode, bool scriptNeedsArgsObj)
1.53 + : script_(script), fun_(fun), osrPc_(osrPc), constructing_(constructing),
1.54 + executionMode_(executionMode), scriptNeedsArgsObj_(scriptNeedsArgsObj)
1.55 + {
1.56 + JS_ASSERT_IF(osrPc, JSOp(*osrPc) == JSOP_LOOPENTRY);
1.57 +
1.58 + // The function here can flow in from anywhere so look up the canonical
1.59 + // function to ensure that we do not try to embed a nursery pointer in
1.60 + // jit-code. Precisely because it can flow in from anywhere, it's not
1.61 + // guaranteed to be non-lazy. Hence, don't access its script!
1.62 + if (fun_) {
1.63 + fun_ = fun_->nonLazyScript()->functionNonDelazifying();
1.64 + JS_ASSERT(fun_->isTenured());
1.65 + }
1.66 +
1.67 + osrStaticScope_ = osrPc ? script->getStaticScope(osrPc) : nullptr;
1.68 +
1.69 + nimplicit_ = StartArgSlot(script) /* scope chain and argument obj */
1.70 + + (fun ? 1 : 0); /* this */
1.71 + nargs_ = fun ? fun->nargs() : 0;
1.72 + nfixedvars_ = script->nfixedvars();
1.73 + nlocals_ = script->nfixed();
1.74 + nstack_ = script->nslots() - script->nfixed();
1.75 + nslots_ = nimplicit_ + nargs_ + nlocals_ + nstack_;
1.76 + }
1.77 +
1.78 + CompileInfo(unsigned nlocals, ExecutionMode executionMode)
1.79 + : script_(nullptr), fun_(nullptr), osrPc_(nullptr), osrStaticScope_(nullptr),
1.80 + constructing_(false), executionMode_(executionMode), scriptNeedsArgsObj_(false)
1.81 + {
1.82 + nimplicit_ = 0;
1.83 + nargs_ = 0;
1.84 + nfixedvars_ = 0;
1.85 + nlocals_ = nlocals;
1.86 + nstack_ = 1; /* For FunctionCompiler::pushPhiInput/popPhiOutput */
1.87 + nslots_ = nlocals_ + nstack_;
1.88 + }
1.89 +
1.90 + JSScript *script() const {
1.91 + return script_;
1.92 + }
1.93 + JSFunction *funMaybeLazy() const {
1.94 + return fun_;
1.95 + }
1.96 + bool constructing() const {
1.97 + return constructing_;
1.98 + }
1.99 + jsbytecode *osrPc() {
1.100 + return osrPc_;
1.101 + }
1.102 + NestedScopeObject *osrStaticScope() const {
1.103 + return osrStaticScope_;
1.104 + }
1.105 +
1.106 + bool hasOsrAt(jsbytecode *pc) {
1.107 + JS_ASSERT(JSOp(*pc) == JSOP_LOOPENTRY);
1.108 + return pc == osrPc();
1.109 + }
1.110 +
1.111 + jsbytecode *startPC() const {
1.112 + return script_->code();
1.113 + }
1.114 + jsbytecode *limitPC() const {
1.115 + return script_->codeEnd();
1.116 + }
1.117 +
1.118 + const char *filename() const {
1.119 + return script_->filename();
1.120 + }
1.121 +
1.122 + unsigned lineno() const {
1.123 + return script_->lineno();
1.124 + }
1.125 + unsigned lineno(jsbytecode *pc) const {
1.126 + return PCToLineNumber(script_, pc);
1.127 + }
1.128 +
1.129 + // Script accessors based on PC.
1.130 +
1.131 + JSAtom *getAtom(jsbytecode *pc) const {
1.132 + return script_->getAtom(GET_UINT32_INDEX(pc));
1.133 + }
1.134 +
1.135 + PropertyName *getName(jsbytecode *pc) const {
1.136 + return script_->getName(GET_UINT32_INDEX(pc));
1.137 + }
1.138 +
1.139 + inline RegExpObject *getRegExp(jsbytecode *pc) const;
1.140 +
1.141 + JSObject *getObject(jsbytecode *pc) const {
1.142 + return script_->getObject(GET_UINT32_INDEX(pc));
1.143 + }
1.144 +
1.145 + inline JSFunction *getFunction(jsbytecode *pc) const;
1.146 +
1.147 + const Value &getConst(jsbytecode *pc) const {
1.148 + return script_->getConst(GET_UINT32_INDEX(pc));
1.149 + }
1.150 +
1.151 + jssrcnote *getNote(GSNCache &gsn, jsbytecode *pc) const {
1.152 + return GetSrcNote(gsn, script(), pc);
1.153 + }
1.154 +
1.155 + // Total number of slots: args, locals, and stack.
1.156 + unsigned nslots() const {
1.157 + return nslots_;
1.158 + }
1.159 +
1.160 + // Number of slots needed for Scope chain, return value,
1.161 + // maybe argumentsobject and this value.
1.162 + unsigned nimplicit() const {
1.163 + return nimplicit_;
1.164 + }
1.165 + // Number of arguments (without counting this value).
1.166 + unsigned nargs() const {
1.167 + return nargs_;
1.168 + }
1.169 + // Number of slots needed for "fixed vars". Note that this is only non-zero
1.170 + // for function code.
1.171 + unsigned nfixedvars() const {
1.172 + return nfixedvars_;
1.173 + }
1.174 + // Number of slots needed for all local variables. This includes "fixed
1.175 + // vars" (see above) and also block-scoped locals.
1.176 + unsigned nlocals() const {
1.177 + return nlocals_;
1.178 + }
1.179 + unsigned ninvoke() const {
1.180 + return nslots_ - nstack_;
1.181 + }
1.182 +
1.183 + uint32_t scopeChainSlot() const {
1.184 + JS_ASSERT(script());
1.185 + return 0;
1.186 + }
1.187 + uint32_t returnValueSlot() const {
1.188 + JS_ASSERT(script());
1.189 + return 1;
1.190 + }
1.191 + uint32_t argsObjSlot() const {
1.192 + JS_ASSERT(hasArguments());
1.193 + return 2;
1.194 + }
1.195 + uint32_t thisSlot() const {
1.196 + JS_ASSERT(funMaybeLazy());
1.197 + JS_ASSERT(nimplicit_ > 0);
1.198 + return nimplicit_ - 1;
1.199 + }
1.200 + uint32_t firstArgSlot() const {
1.201 + return nimplicit_;
1.202 + }
1.203 + uint32_t argSlotUnchecked(uint32_t i) const {
1.204 + // During initialization, some routines need to get at arg
1.205 + // slots regardless of how regular argument access is done.
1.206 + JS_ASSERT(i < nargs_);
1.207 + return nimplicit_ + i;
1.208 + }
1.209 + uint32_t argSlot(uint32_t i) const {
1.210 + // This should only be accessed when compiling functions for
1.211 + // which argument accesses don't need to go through the
1.212 + // argument object.
1.213 + JS_ASSERT(!argsObjAliasesFormals());
1.214 + return argSlotUnchecked(i);
1.215 + }
1.216 + uint32_t firstLocalSlot() const {
1.217 + return nimplicit_ + nargs_;
1.218 + }
1.219 + uint32_t localSlot(uint32_t i) const {
1.220 + return firstLocalSlot() + i;
1.221 + }
1.222 + uint32_t firstStackSlot() const {
1.223 + return firstLocalSlot() + nlocals();
1.224 + }
1.225 + uint32_t stackSlot(uint32_t i) const {
1.226 + return firstStackSlot() + i;
1.227 + }
1.228 +
1.229 + uint32_t startArgSlot() const {
1.230 + JS_ASSERT(script());
1.231 + return StartArgSlot(script());
1.232 + }
1.233 + uint32_t endArgSlot() const {
1.234 + JS_ASSERT(script());
1.235 + return CountArgSlots(script(), funMaybeLazy());
1.236 + }
1.237 +
1.238 + uint32_t totalSlots() const {
1.239 + JS_ASSERT(script() && funMaybeLazy());
1.240 + return nimplicit() + nargs() + nlocals();
1.241 + }
1.242 +
1.243 + bool isSlotAliased(uint32_t index, NestedScopeObject *staticScope) const {
1.244 + JS_ASSERT(index >= startArgSlot());
1.245 +
1.246 + if (funMaybeLazy() && index == thisSlot())
1.247 + return false;
1.248 +
1.249 + uint32_t arg = index - firstArgSlot();
1.250 + if (arg < nargs())
1.251 + return script()->formalIsAliased(arg);
1.252 +
1.253 + uint32_t local = index - firstLocalSlot();
1.254 + if (local < nlocals()) {
1.255 + // First, check if this local is a var.
1.256 + if (local < nfixedvars())
1.257 + return script()->varIsAliased(local);
1.258 +
1.259 + // Otherwise, it might be part of a block scope.
1.260 + for (; staticScope; staticScope = staticScope->enclosingNestedScope()) {
1.261 + if (!staticScope->is<StaticBlockObject>())
1.262 + continue;
1.263 + StaticBlockObject &blockObj = staticScope->as<StaticBlockObject>();
1.264 + if (blockObj.localOffset() < local) {
1.265 + if (local - blockObj.localOffset() < blockObj.numVariables())
1.266 + return blockObj.isAliased(local - blockObj.localOffset());
1.267 + return false;
1.268 + }
1.269 + }
1.270 +
1.271 + // In this static scope, this var is dead.
1.272 + return false;
1.273 + }
1.274 +
1.275 + JS_ASSERT(index >= firstStackSlot());
1.276 + return false;
1.277 + }
1.278 +
1.279 + bool isSlotAliasedAtEntry(uint32_t index) const {
1.280 + return isSlotAliased(index, nullptr);
1.281 + }
1.282 + bool isSlotAliasedAtOsr(uint32_t index) const {
1.283 + return isSlotAliased(index, osrStaticScope());
1.284 + }
1.285 +
1.286 + bool hasArguments() const {
1.287 + return script()->argumentsHasVarBinding();
1.288 + }
1.289 + bool argumentsAliasesFormals() const {
1.290 + return script()->argumentsAliasesFormals();
1.291 + }
1.292 + bool needsArgsObj() const {
1.293 + return scriptNeedsArgsObj_;
1.294 + }
1.295 + bool argsObjAliasesFormals() const {
1.296 + return scriptNeedsArgsObj_ && !script()->strict();
1.297 + }
1.298 +
1.299 + ExecutionMode executionMode() const {
1.300 + return executionMode_;
1.301 + }
1.302 +
1.303 + bool executionModeIsAnalysis() const {
1.304 + return executionMode_ == DefinitePropertiesAnalysis || executionMode_ == ArgumentsUsageAnalysis;
1.305 + }
1.306 +
1.307 + bool isParallelExecution() const {
1.308 + return executionMode_ == ParallelExecution;
1.309 + }
1.310 +
1.311 + bool canOptimizeOutSlot(uint32_t i) const {
1.312 + if (script()->strict())
1.313 + return true;
1.314 +
1.315 + // Function.arguments can be used to access all arguments in
1.316 + // non-strict scripts, so we can't optimize out any arguments.
1.317 + return !(firstArgSlot() <= i && i - firstArgSlot() < nargs());
1.318 + }
1.319 +
1.320 + private:
1.321 + unsigned nimplicit_;
1.322 + unsigned nargs_;
1.323 + unsigned nfixedvars_;
1.324 + unsigned nlocals_;
1.325 + unsigned nstack_;
1.326 + unsigned nslots_;
1.327 + JSScript *script_;
1.328 + JSFunction *fun_;
1.329 + jsbytecode *osrPc_;
1.330 + NestedScopeObject *osrStaticScope_;
1.331 + bool constructing_;
1.332 + ExecutionMode executionMode_;
1.333 +
1.334 + // Whether a script needs an arguments object is unstable over compilation
1.335 + // since the arguments optimization could be marked as failed on the main
1.336 + // thread, so cache a value here and use it throughout for consistency.
1.337 + bool scriptNeedsArgsObj_;
1.338 +};
1.339 +
1.340 +} // namespace jit
1.341 +} // namespace js
1.342 +
1.343 +#endif /* jit_CompileInfo_h */
