The Tor Browser: js/src/jit/MIRGraph.h@b8a032363ba2 (annotated)

js/src/jit/MIRGraph.h@b8a032363ba2 (annotated)

js/src/jit/MIRGraph.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

 /* -*- 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_MIRGraph_h
 #define jit_MIRGraph_h
 // This file declares the data structures used to build a control-flow graph
 // containing MIR.
 #include "jit/FixedList.h"
 #include "jit/IonAllocPolicy.h"
 #include "jit/MIR.h"
 namespace js {
 namespace jit {
 class BytecodeAnalysis;
 class MBasicBlock;
 class MIRGraph;
 class MStart;
 class MDefinitionIterator;
 typedef InlineListIterator<MInstruction> MInstructionIterator;
 typedef InlineListReverseIterator<MInstruction> MInstructionReverseIterator;
 typedef InlineForwardListIterator<MPhi> MPhiIterator;
 typedef InlineForwardListIterator<MResumePoint> MResumePointIterator;
 class LBlock;
 class MBasicBlock : public TempObject, public InlineListNode<MBasicBlock>
 {
   public:
     enum Kind {
         NORMAL,
         PENDING_LOOP_HEADER,
         LOOP_HEADER,
         SPLIT_EDGE,
         DEAD
     };
   private:
     MBasicBlock(MIRGraph &graph, CompileInfo &info, jsbytecode *pc, Kind kind);
     bool init();
     void copySlots(MBasicBlock *from);
     bool inherit(TempAllocator &alloc, BytecodeAnalysis *analysis, MBasicBlock *pred,
                  uint32_t popped, unsigned stackPhiCount = 0);
     bool inheritResumePoint(MBasicBlock *pred);
     void assertUsesAreNotWithin(MUseIterator use, MUseIterator end);
     // This block cannot be reached by any means.
     bool unreachable_;
     // Pushes a copy of a local variable or argument.
     void pushVariable(uint32_t slot);
     // Sets a variable slot to the top of the stack, correctly creating copies
     // as needed.
     void setVariable(uint32_t slot);
   public:
     ///////////////////////////////////////////////////////
     ////////// BEGIN GRAPH BUILDING INSTRUCTIONS //////////
     ///////////////////////////////////////////////////////
     // Creates a new basic block for a MIR generator. If |pred| is not nullptr,
     // its slots and stack depth are initialized from |pred|.
     static MBasicBlock *New(MIRGraph &graph, BytecodeAnalysis *analysis, CompileInfo &info,
                             MBasicBlock *pred, jsbytecode *entryPc, Kind kind);
     static MBasicBlock *NewPopN(MIRGraph &graph, CompileInfo &info,
                                 MBasicBlock *pred, jsbytecode *entryPc, Kind kind, uint32_t popn);
     static MBasicBlock *NewWithResumePoint(MIRGraph &graph, CompileInfo &info,
                                            MBasicBlock *pred, jsbytecode *entryPc,
                                            MResumePoint *resumePoint);
     static MBasicBlock *NewPendingLoopHeader(MIRGraph &graph, CompileInfo &info,
                                              MBasicBlock *pred, jsbytecode *entryPc,
                                              unsigned loopStateSlots);
     static MBasicBlock *NewSplitEdge(MIRGraph &graph, CompileInfo &info, MBasicBlock *pred);
     static MBasicBlock *NewAbortPar(MIRGraph &graph, CompileInfo &info,
                                     MBasicBlock *pred, jsbytecode *entryPc,
                                     MResumePoint *resumePoint);
     static MBasicBlock *NewAsmJS(MIRGraph &graph, CompileInfo &info,
                                  MBasicBlock *pred, Kind kind);
     bool dominates(const MBasicBlock *other) const;
     void setId(uint32_t id) {
         id_ = id;
     }
     // Mark the current block and all dominated blocks as unreachable.
     void setUnreachable();
     bool unreachable() const {
         return unreachable_;
     }
     // Move the definition to the top of the stack.
     void pick(int32_t depth);
     // Exchange 2 stack slots at the defined depth
     void swapAt(int32_t depth);
     // Gets the instruction associated with various slot types.
     MDefinition *peek(int32_t depth);
     MDefinition *scopeChain();
     MDefinition *argumentsObject();
     // Increase the number of slots available
     bool increaseSlots(size_t num);
     bool ensureHasSlots(size_t num);
     // Initializes a slot value; must not be called for normal stack
     // operations, as it will not create new SSA names for copies.
     void initSlot(uint32_t index, MDefinition *ins);
     // Discard the slot at the given depth, lowering all slots above.
     void shimmySlots(int discardDepth);
     // In an OSR block, set all MOsrValues to use the MResumePoint attached to
     // the MStart.
     void linkOsrValues(MStart *start);
     // Sets the instruction associated with various slot types. The
     // instruction must lie at the top of the stack.
     void setLocal(uint32_t local);
     void setArg(uint32_t arg);
     void setSlot(uint32_t slot);
     void setSlot(uint32_t slot, MDefinition *ins);
     // Rewrites a slot directly, bypassing the stack transition. This should
     // not be used under most circumstances.
     void rewriteSlot(uint32_t slot, MDefinition *ins);
     // Rewrites a slot based on its depth (same as argument to peek()).
     void rewriteAtDepth(int32_t depth, MDefinition *ins);
     // Tracks an instruction as being pushed onto the operand stack.
     void push(MDefinition *ins);
     void pushArg(uint32_t arg);
     void pushLocal(uint32_t local);
     void pushSlot(uint32_t slot);
     void setScopeChain(MDefinition *ins);
     void setArgumentsObject(MDefinition *ins);
     // Returns the top of the stack, then decrements the virtual stack pointer.
     MDefinition *pop();
     void popn(uint32_t n);
     // Adds an instruction to this block's instruction list. |ins| may be
     // nullptr to simplify OOM checking.
     void add(MInstruction *ins);
     // Marks the last instruction of the block; no further instructions
     // can be added.
     void end(MControlInstruction *ins);
     // Adds a phi instruction, but does not set successorWithPhis.
     void addPhi(MPhi *phi);
     // Adds a resume point to this block.
     void addResumePoint(MResumePoint *resume) {
         resumePoints_.pushFront(resume);
     }
     // Adds a predecessor. Every predecessor must have the same exit stack
     // depth as the entry state to this block. Adding a predecessor
     // automatically creates phi nodes and rewrites uses as needed.
     bool addPredecessor(TempAllocator &alloc, MBasicBlock *pred);
     bool addPredecessorPopN(TempAllocator &alloc, MBasicBlock *pred, uint32_t popped);
     // Stranger utilities used for inlining.
     bool addPredecessorWithoutPhis(MBasicBlock *pred);
     void inheritSlots(MBasicBlock *parent);
     bool initEntrySlots(TempAllocator &alloc);
     // Replaces an edge for a given block with a new block. This is
     // used for critical edge splitting and also for inserting
     // bailouts during ParallelSafetyAnalysis.
     //
     // Note: If successorWithPhis is set, you must not be replacing it.
     void replacePredecessor(MBasicBlock *old, MBasicBlock *split);
     void replaceSuccessor(size_t pos, MBasicBlock *split);
     // Removes `pred` from the predecessor list.  `pred` should not be
     // the final predecessor. If this block defines phis, removes the
     // entry for `pred` and updates the indices of later entries.
     // This may introduce redundant phis if the new block has fewer
     // than two predecessors.
     void removePredecessor(MBasicBlock *pred);
     // Resets all the dominator info so that it can be recomputed.
     void clearDominatorInfo();
     // Sets a back edge. This places phi nodes and rewrites instructions within
     // the current loop as necessary. If the backedge introduces new types for
     // phis at the loop header, returns a disabling abort.
     AbortReason setBackedge(MBasicBlock *block);
     bool setBackedgeAsmJS(MBasicBlock *block);
     // Resets a LOOP_HEADER block to a NORMAL block.  This is needed when
     // optimizations remove the backedge.
     void clearLoopHeader();
     // Propagates phis placed in a loop header down to this successor block.
     void inheritPhis(MBasicBlock *header);
     // Compute the types for phis in this block according to their inputs.
     bool specializePhis();
     void insertBefore(MInstruction *at, MInstruction *ins);
     void insertAfter(MInstruction *at, MInstruction *ins);
     // Add an instruction to this block, from elsewhere in the graph.
     void addFromElsewhere(MInstruction *ins);
     // Move an instruction. Movement may cross block boundaries.
     void moveBefore(MInstruction *at, MInstruction *ins);
     // Removes an instruction with the intention to discard it.
     void discard(MInstruction *ins);
     void discardLastIns();
     MInstructionIterator discardAt(MInstructionIterator &iter);
     MInstructionReverseIterator discardAt(MInstructionReverseIterator &iter);
     MDefinitionIterator discardDefAt(MDefinitionIterator &iter);
     void discardAllInstructions();
     void discardAllPhiOperands();
     void discardAllPhis();
     void discardAllResumePoints(bool discardEntry = true);
     // Discards a phi instruction and updates predecessor successorWithPhis.
     MPhiIterator discardPhiAt(MPhiIterator &at);
     // Mark this block as having been removed from the graph.
     void markAsDead() {
         kind_ = DEAD;
     }
     ///////////////////////////////////////////////////////
     /////////// END GRAPH BUILDING INSTRUCTIONS ///////////
     ///////////////////////////////////////////////////////
     MIRGraph &graph() {
         return graph_;
     }
     CompileInfo &info() const {
         return info_;
     }
     jsbytecode *pc() const {
         return pc_;
     }
     uint32_t nslots() const {
         return slots_.length();
     }
     uint32_t id() const {
         return id_;
     }
     uint32_t numPredecessors() const {
         return predecessors_.length();
     }
     uint32_t domIndex() const {
         JS_ASSERT(!isDead());
         return domIndex_;
     }
     void setDomIndex(uint32_t d) {
         domIndex_ = d;
     }
     MBasicBlock *getPredecessor(uint32_t i) const {
         return predecessors_[i];
     }
     MControlInstruction *lastIns() const {
         return lastIns_;
     }
     MPhiIterator phisBegin() const {
         return phis_.begin();
     }
     MPhiIterator phisEnd() const {
         return phis_.end();
     }
     bool phisEmpty() const {
         return phis_.empty();
     }
     MResumePointIterator resumePointsBegin() const {
         return resumePoints_.begin();
     }
     MResumePointIterator resumePointsEnd() const {
         return resumePoints_.end();
     }
     bool resumePointsEmpty() const {
         return resumePoints_.empty();
     }
     MInstructionIterator begin() {
         return instructions_.begin();
     }
     MInstructionIterator begin(MInstruction *at) {
         JS_ASSERT(at->block() == this);
         return instructions_.begin(at);
     }
     MInstructionIterator end() {
         return instructions_.end();
     }
     MInstructionReverseIterator rbegin() {
         return instructions_.rbegin();
     }
     MInstructionReverseIterator rbegin(MInstruction *at) {
         JS_ASSERT(at->block() == this);
         return instructions_.rbegin(at);
     }
     MInstructionReverseIterator rend() {
         return instructions_.rend();
     }
     bool isLoopHeader() const {
         return kind_ == LOOP_HEADER;
     }
     bool hasUniqueBackedge() const {
         JS_ASSERT(isLoopHeader());
         JS_ASSERT(numPredecessors() >= 2);
         return numPredecessors() == 2;
     }
     MBasicBlock *backedge() const {
         JS_ASSERT(hasUniqueBackedge());
         return getPredecessor(numPredecessors() - 1);
     }
     MBasicBlock *loopHeaderOfBackedge() const {
         JS_ASSERT(isLoopBackedge());
         return getSuccessor(numSuccessors() - 1);
     }
     MBasicBlock *loopPredecessor() const {
         JS_ASSERT(isLoopHeader());
         return getPredecessor(0);
     }
     bool isLoopBackedge() const {
         if (!numSuccessors())
             return false;
         MBasicBlock *lastSuccessor = getSuccessor(numSuccessors() - 1);
         return lastSuccessor->isLoopHeader() &&
                lastSuccessor->hasUniqueBackedge() &&
                lastSuccessor->backedge() == this;
     }
     bool isSplitEdge() const {
         return kind_ == SPLIT_EDGE;
     }
     bool isDead() const {
         return kind_ == DEAD;
     }
     uint32_t stackDepth() const {
         return stackPosition_;
     }
     void setStackDepth(uint32_t depth) {
         stackPosition_ = depth;
     }
     bool isMarked() const {
         return mark_;
     }
     void mark() {
         mark_ = true;
     }
     void unmark() {
         mark_ = false;
     }
     void makeStart(MStart *start) {
         add(start);
         start_ = start;
     }
     MStart *start() const {
         return start_;
     }
     MBasicBlock *immediateDominator() const {
         return immediateDominator_;
     }
     void setImmediateDominator(MBasicBlock *dom) {
         immediateDominator_ = dom;
     }
     MTest *immediateDominatorBranch(BranchDirection *pdirection);
     size_t numImmediatelyDominatedBlocks() const {
         return immediatelyDominated_.length();
     }
     MBasicBlock *getImmediatelyDominatedBlock(size_t i) const {
         return immediatelyDominated_[i];
     }
     MBasicBlock **immediatelyDominatedBlocksBegin() {
         return immediatelyDominated_.begin();
     }
     MBasicBlock **immediatelyDominatedBlocksEnd() {
         return immediatelyDominated_.end();
     }
     size_t numDominated() const {
         return numDominated_;
     }
     void addNumDominated(size_t n) {
         numDominated_ += n;
     }
     bool addImmediatelyDominatedBlock(MBasicBlock *child);
     // This function retrieves the internal instruction associated with a
     // slot, and should not be used for normal stack operations. It is an
     // internal helper that is also used to enhance spew.
     MDefinition *getSlot(uint32_t index);
     MResumePoint *entryResumePoint() const {
         return entryResumePoint_;
     }
     MResumePoint *callerResumePoint() {
         return entryResumePoint()->caller();
     }
     void setCallerResumePoint(MResumePoint *caller) {
         entryResumePoint()->setCaller(caller);
     }
     size_t numEntrySlots() const {
         return entryResumePoint()->numOperands();
     }
     MDefinition *getEntrySlot(size_t i) const {
         JS_ASSERT(i < numEntrySlots());
         return entryResumePoint()->getOperand(i);
     }
     LBlock *lir() const {
         return lir_;
     }
     void assignLir(LBlock *lir) {
         JS_ASSERT(!lir_);
         lir_ = lir;
     }
     MBasicBlock *successorWithPhis() const {
         return successorWithPhis_;
     }
     uint32_t positionInPhiSuccessor() const {
         return positionInPhiSuccessor_;
     }
     void setSuccessorWithPhis(MBasicBlock *successor, uint32_t id) {
         successorWithPhis_ = successor;
         positionInPhiSuccessor_ = id;
     }
     size_t numSuccessors() const;
     MBasicBlock *getSuccessor(size_t index) const;
     size_t getSuccessorIndex(MBasicBlock *) const;
     void setLoopDepth(uint32_t loopDepth) {
         loopDepth_ = loopDepth;
     }
     uint32_t loopDepth() const {
         return loopDepth_;
     }
     bool strict() const {
         return info_.script()->strict();
     }
     void dumpStack(FILE *fp);
     void dump(FILE *fp);
     void dump();
     // Track bailouts by storing the current pc in MIR instruction added at this
     // cycle. This is also used for tracking calls when profiling.
     void updateTrackedPc(jsbytecode *pc) {
         trackedPc_ = pc;
     }
     jsbytecode *trackedPc() {
         return trackedPc_;
     }
   private:
     MIRGraph &graph_;
     CompileInfo &info_; // Each block originates from a particular script.
     InlineList<MInstruction> instructions_;
     Vector<MBasicBlock *, 1, IonAllocPolicy> predecessors_;
     InlineForwardList<MPhi> phis_;
     InlineForwardList<MResumePoint> resumePoints_;
     FixedList<MDefinition *> slots_;
     uint32_t stackPosition_;
     MControlInstruction *lastIns_;
     jsbytecode *pc_;
     uint32_t id_;
     uint32_t domIndex_; // Index in the dominator tree.
     LBlock *lir_;
     MStart *start_;
     MResumePoint *entryResumePoint_;
     MBasicBlock *successorWithPhis_;
     uint32_t positionInPhiSuccessor_;
     Kind kind_;
     uint32_t loopDepth_;
     // Utility mark for traversal algorithms.
     bool mark_;
     Vector<MBasicBlock *, 1, IonAllocPolicy> immediatelyDominated_;
     MBasicBlock *immediateDominator_;
     size_t numDominated_;
     jsbytecode *trackedPc_;
 #if defined (JS_ION_PERF)
     unsigned lineno_;
     unsigned columnIndex_;
   public:
     void setLineno(unsigned l) { lineno_ = l; }
     unsigned lineno() const { return lineno_; }
     void setColumnIndex(unsigned c) { columnIndex_ = c; }
     unsigned columnIndex() const { return columnIndex_; }
 #endif
 };
 typedef InlineListIterator<MBasicBlock> MBasicBlockIterator;
 typedef InlineListIterator<MBasicBlock> ReversePostorderIterator;
 typedef InlineListReverseIterator<MBasicBlock> PostorderIterator;
 typedef Vector<MBasicBlock *, 1, IonAllocPolicy> MIRGraphReturns;
 class MIRGraph
 {
     InlineList<MBasicBlock> blocks_;
     TempAllocator *alloc_;
     MIRGraphReturns *returnAccumulator_;
     uint32_t blockIdGen_;
     uint32_t idGen_;
     MBasicBlock *osrBlock_;
     MStart *osrStart_;
     size_t numBlocks_;
     bool hasTryBlock_;
   public:
     MIRGraph(TempAllocator *alloc)
       : alloc_(alloc),
         returnAccumulator_(nullptr),
         blockIdGen_(0),
         idGen_(1),
         osrBlock_(nullptr),
         osrStart_(nullptr),
         numBlocks_(0),
         hasTryBlock_(false)
     { }
     TempAllocator &alloc() const {
         return *alloc_;
     }
     void addBlock(MBasicBlock *block);
     void insertBlockAfter(MBasicBlock *at, MBasicBlock *block);
     void unmarkBlocks();
     void setReturnAccumulator(MIRGraphReturns *accum) {
         returnAccumulator_ = accum;
     }
     MIRGraphReturns *returnAccumulator() const {
         return returnAccumulator_;
     }
     bool addReturn(MBasicBlock *returnBlock) {
         if (!returnAccumulator_)
             return true;
         return returnAccumulator_->append(returnBlock);
     }
     MBasicBlock *entryBlock() {
         return *blocks_.begin();
     }
     void clearBlockList() {
         blocks_.clear();
         blockIdGen_ = 0;
         numBlocks_ = 0;
     }
     void resetInstructionNumber() {
         // This intentionally starts above 0. The id 0 is in places used to
         // indicate a failure to perform an operation on an instruction.
         idGen_ = 1;
     }
     MBasicBlockIterator begin() {
         return blocks_.begin();
     }
     MBasicBlockIterator begin(MBasicBlock *at) {
         return blocks_.begin(at);
     }
     MBasicBlockIterator end() {
         return blocks_.end();
     }
     PostorderIterator poBegin() {
         return blocks_.rbegin();
     }
     PostorderIterator poEnd() {
         return blocks_.rend();
     }
     ReversePostorderIterator rpoBegin() {
         return blocks_.begin();
     }
     ReversePostorderIterator rpoBegin(MBasicBlock *at) {
         return blocks_.begin(at);
     }
     ReversePostorderIterator rpoEnd() {
         return blocks_.end();
     }
     void removeBlocksAfter(MBasicBlock *block);
     void removeBlock(MBasicBlock *block);
     void moveBlockToEnd(MBasicBlock *block) {
         JS_ASSERT(block->id());
         blocks_.remove(block);
         blocks_.pushBack(block);
     }
     size_t numBlocks() const {
         return numBlocks_;
     }
     uint32_t numBlockIds() const {
         return blockIdGen_;
     }
     void allocDefinitionId(MDefinition *ins) {
         ins->setId(idGen_++);
     }
     uint32_t getNumInstructionIds() {
         return idGen_;
     }
     MResumePoint *entryResumePoint() {
         return blocks_.begin()->entryResumePoint();
     }
     void copyIds(const MIRGraph &other) {
         idGen_ = other.idGen_;
         blockIdGen_ = other.blockIdGen_;
         numBlocks_ = other.numBlocks_;
     }
     void setOsrBlock(MBasicBlock *osrBlock) {
         JS_ASSERT(!osrBlock_);
         osrBlock_ = osrBlock;
     }
     MBasicBlock *osrBlock() {
         return osrBlock_;
     }
     void setOsrStart(MStart *osrStart) {
         osrStart_ = osrStart;
     }
     MStart *osrStart() {
         return osrStart_;
     }
     bool hasTryBlock() const {
         return hasTryBlock_;
     }
     void setHasTryBlock() {
         hasTryBlock_ = true;
     }
     // The per-thread context. So as not to modify the calling convention for
     // parallel code, we obtain the current ForkJoinContext from thread-local
     // storage.  This helper method will lazilly insert an MForkJoinContext
     // instruction in the entry block and return the definition.
     MDefinition *forkJoinContext();
     void dump(FILE *fp);
     void dump();
 };
 class MDefinitionIterator
 {
   friend class MBasicBlock;
   private:
     MBasicBlock *block_;
     MPhiIterator phiIter_;
     MInstructionIterator iter_;
     bool atPhi() const {
         return phiIter_ != block_->phisEnd();
     }
     MDefinition *getIns() {
         if (atPhi())
             return *phiIter_;
         return *iter_;
     }
     void next() {
         if (atPhi())
             phiIter_++;
         else
             iter_++;
     }
     bool more() const {
         return atPhi() || (*iter_) != block_->lastIns();
     }
   public:
     MDefinitionIterator(MBasicBlock *block)
       : block_(block),
         phiIter_(block->phisBegin()),
         iter_(block->begin())
     { }
     MDefinitionIterator operator ++(int) {
         MDefinitionIterator old(*this);
         if (more())
             next();
         return old;
     }
     operator bool() const {
         return more();
     }
     MDefinition *operator *() {
         return getIns();
     }
     MDefinition *operator ->() {
         return getIns();
     }
 };
 } // namespace jit
 } // namespace js
 #endif /* jit_MIRGraph_h */

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js/src/jit/MIRGraph.h@b8a032363ba2 (annotated)

js/src/jit/MIRGraph.h