The Tor Browser: js/src/jit/CompileInfo.h@6474c204b198 (annotated)

js/src/jit/CompileInfo.h@6474c204b198 (annotated)

js/src/jit/CompileInfo.h

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  * vim: set ts=8 sts=4 et sw=4 tw=99:
  * This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef jit_CompileInfo_h
 #define jit_CompileInfo_h
 #include "jsfun.h"
 #include "jit/Registers.h"
 #include "vm/ScopeObject.h"
 namespace js {
 namespace jit {
 inline unsigned
 StartArgSlot(JSScript *script)
 {
     // Reserved slots:
     // Slot 0: Scope chain.
     // Slot 1: Return value.
     // When needed:
     // Slot 2: Argumentsobject.
     // Note: when updating this, please also update the assert in SnapshotWriter::startFrame
     return 2 + (script->argumentsHasVarBinding() ? 1 : 0);
 }
 inline unsigned
 CountArgSlots(JSScript *script, JSFunction *fun)
 {
     // Slot x + 0: This value.
     // Slot x + 1: Argument 1.
     // ...
     // Slot x + n: Argument n.
     // Note: when updating this, please also update the assert in SnapshotWriter::startFrame
     return StartArgSlot(script) + (fun ? fun->nargs() + 1 : 0);
 }
 // Contains information about the compilation source for IR being generated.
 class CompileInfo
 {
   public:
     CompileInfo(JSScript *script, JSFunction *fun, jsbytecode *osrPc, bool constructing,
                 ExecutionMode executionMode, bool scriptNeedsArgsObj)
       : script_(script), fun_(fun), osrPc_(osrPc), constructing_(constructing),
         executionMode_(executionMode), scriptNeedsArgsObj_(scriptNeedsArgsObj)
     {
         JS_ASSERT_IF(osrPc, JSOp(*osrPc) == JSOP_LOOPENTRY);
         // The function here can flow in from anywhere so look up the canonical
         // function to ensure that we do not try to embed a nursery pointer in
         // jit-code. Precisely because it can flow in from anywhere, it's not
         // guaranteed to be non-lazy. Hence, don't access its script!
         if (fun_) {
             fun_ = fun_->nonLazyScript()->functionNonDelazifying();
             JS_ASSERT(fun_->isTenured());
         }
         osrStaticScope_ = osrPc ? script->getStaticScope(osrPc) : nullptr;
         nimplicit_ = StartArgSlot(script)                   /* scope chain and argument obj */
                    + (fun ? 1 : 0);                         /* this */
         nargs_ = fun ? fun->nargs() : 0;
         nfixedvars_ = script->nfixedvars();
         nlocals_ = script->nfixed();
         nstack_ = script->nslots() - script->nfixed();
         nslots_ = nimplicit_ + nargs_ + nlocals_ + nstack_;
     }
     CompileInfo(unsigned nlocals, ExecutionMode executionMode)
       : script_(nullptr), fun_(nullptr), osrPc_(nullptr), osrStaticScope_(nullptr),
         constructing_(false), executionMode_(executionMode), scriptNeedsArgsObj_(false)
     {
         nimplicit_ = 0;
         nargs_ = 0;
         nfixedvars_ = 0;
         nlocals_ = nlocals;
         nstack_ = 1;  /* For FunctionCompiler::pushPhiInput/popPhiOutput */
         nslots_ = nlocals_ + nstack_;
     }
     JSScript *script() const {
         return script_;
     }
     JSFunction *funMaybeLazy() const {
         return fun_;
     }
     bool constructing() const {
         return constructing_;
     }
     jsbytecode *osrPc() {
         return osrPc_;
     }
     NestedScopeObject *osrStaticScope() const {
         return osrStaticScope_;
     }
     bool hasOsrAt(jsbytecode *pc) {
         JS_ASSERT(JSOp(*pc) == JSOP_LOOPENTRY);
         return pc == osrPc();
     }
     jsbytecode *startPC() const {
         return script_->code();
     }
     jsbytecode *limitPC() const {
         return script_->codeEnd();
     }
     const char *filename() const {
         return script_->filename();
     }
     unsigned lineno() const {
         return script_->lineno();
     }
     unsigned lineno(jsbytecode *pc) const {
         return PCToLineNumber(script_, pc);
     }
     // Script accessors based on PC.
     JSAtom *getAtom(jsbytecode *pc) const {
         return script_->getAtom(GET_UINT32_INDEX(pc));
     }
     PropertyName *getName(jsbytecode *pc) const {
         return script_->getName(GET_UINT32_INDEX(pc));
     }
     inline RegExpObject *getRegExp(jsbytecode *pc) const;
     JSObject *getObject(jsbytecode *pc) const {
         return script_->getObject(GET_UINT32_INDEX(pc));
     }
     inline JSFunction *getFunction(jsbytecode *pc) const;
     const Value &getConst(jsbytecode *pc) const {
         return script_->getConst(GET_UINT32_INDEX(pc));
     }
     jssrcnote *getNote(GSNCache &gsn, jsbytecode *pc) const {
         return GetSrcNote(gsn, script(), pc);
     }
     // Total number of slots: args, locals, and stack.
     unsigned nslots() const {
         return nslots_;
     }
     // Number of slots needed for Scope chain, return value,
     // maybe argumentsobject and this value.
     unsigned nimplicit() const {
         return nimplicit_;
     }
     // Number of arguments (without counting this value).
     unsigned nargs() const {
         return nargs_;
     }
     // Number of slots needed for "fixed vars".  Note that this is only non-zero
     // for function code.
     unsigned nfixedvars() const {
         return nfixedvars_;
     }
     // Number of slots needed for all local variables.  This includes "fixed
     // vars" (see above) and also block-scoped locals.
     unsigned nlocals() const {
         return nlocals_;
     }
     unsigned ninvoke() const {
         return nslots_ - nstack_;
     }
     uint32_t scopeChainSlot() const {
         JS_ASSERT(script());
         return 0;
     }
     uint32_t returnValueSlot() const {
         JS_ASSERT(script());
         return 1;
     }
     uint32_t argsObjSlot() const {
         JS_ASSERT(hasArguments());
         return 2;
     }
     uint32_t thisSlot() const {
         JS_ASSERT(funMaybeLazy());
         JS_ASSERT(nimplicit_ > 0);
         return nimplicit_ - 1;
     }
     uint32_t firstArgSlot() const {
         return nimplicit_;
     }
     uint32_t argSlotUnchecked(uint32_t i) const {
         // During initialization, some routines need to get at arg
         // slots regardless of how regular argument access is done.
         JS_ASSERT(i < nargs_);
         return nimplicit_ + i;
     }
     uint32_t argSlot(uint32_t i) const {
         // This should only be accessed when compiling functions for
         // which argument accesses don't need to go through the
         // argument object.
         JS_ASSERT(!argsObjAliasesFormals());
         return argSlotUnchecked(i);
     }
     uint32_t firstLocalSlot() const {
         return nimplicit_ + nargs_;
     }
     uint32_t localSlot(uint32_t i) const {
         return firstLocalSlot() + i;
     }
     uint32_t firstStackSlot() const {
         return firstLocalSlot() + nlocals();
     }
     uint32_t stackSlot(uint32_t i) const {
         return firstStackSlot() + i;
     }
     uint32_t startArgSlot() const {
         JS_ASSERT(script());
         return StartArgSlot(script());
     }
     uint32_t endArgSlot() const {
         JS_ASSERT(script());
         return CountArgSlots(script(), funMaybeLazy());
     }
     uint32_t totalSlots() const {
         JS_ASSERT(script() && funMaybeLazy());
         return nimplicit() + nargs() + nlocals();
     }
     bool isSlotAliased(uint32_t index, NestedScopeObject *staticScope) const {
         JS_ASSERT(index >= startArgSlot());
         if (funMaybeLazy() && index == thisSlot())
             return false;
         uint32_t arg = index - firstArgSlot();
         if (arg < nargs())
             return script()->formalIsAliased(arg);
         uint32_t local = index - firstLocalSlot();
         if (local < nlocals()) {
             // First, check if this local is a var.
             if (local < nfixedvars())
                 return script()->varIsAliased(local);
             // Otherwise, it might be part of a block scope.
             for (; staticScope; staticScope = staticScope->enclosingNestedScope()) {
                 if (!staticScope->is<StaticBlockObject>())
                     continue;
                 StaticBlockObject &blockObj = staticScope->as<StaticBlockObject>();
                 if (blockObj.localOffset() < local) {
                     if (local - blockObj.localOffset() < blockObj.numVariables())
                         return blockObj.isAliased(local - blockObj.localOffset());
                     return false;
                 }
             }
             // In this static scope, this var is dead.
             return false;
         }
         JS_ASSERT(index >= firstStackSlot());
         return false;
     }
     bool isSlotAliasedAtEntry(uint32_t index) const {
         return isSlotAliased(index, nullptr);
     }
     bool isSlotAliasedAtOsr(uint32_t index) const {
         return isSlotAliased(index, osrStaticScope());
     }
     bool hasArguments() const {
         return script()->argumentsHasVarBinding();
     }
     bool argumentsAliasesFormals() const {
         return script()->argumentsAliasesFormals();
     }
     bool needsArgsObj() const {
         return scriptNeedsArgsObj_;
     }
     bool argsObjAliasesFormals() const {
         return scriptNeedsArgsObj_ && !script()->strict();
     }
     ExecutionMode executionMode() const {
         return executionMode_;
     }
     bool executionModeIsAnalysis() const {
         return executionMode_ == DefinitePropertiesAnalysis || executionMode_ == ArgumentsUsageAnalysis;
     }
     bool isParallelExecution() const {
         return executionMode_ == ParallelExecution;
     }
     bool canOptimizeOutSlot(uint32_t i) const {
         if (script()->strict())
             return true;
         // Function.arguments can be used to access all arguments in
         // non-strict scripts, so we can't optimize out any arguments.
         return !(firstArgSlot() <= i && i - firstArgSlot() < nargs());
     }
   private:
     unsigned nimplicit_;
     unsigned nargs_;
     unsigned nfixedvars_;
     unsigned nlocals_;
     unsigned nstack_;
     unsigned nslots_;
     JSScript *script_;
     JSFunction *fun_;
     jsbytecode *osrPc_;
     NestedScopeObject *osrStaticScope_;
     bool constructing_;
     ExecutionMode executionMode_;
     // Whether a script needs an arguments object is unstable over compilation
     // since the arguments optimization could be marked as failed on the main
     // thread, so cache a value here and use it throughout for consistency.
     bool scriptNeedsArgsObj_;
 };
 } // namespace jit
 } // namespace js
 #endif /* jit_CompileInfo_h */

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js/src/jit/CompileInfo.h@6474c204b198 (annotated)

js/src/jit/CompileInfo.h