michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef jit_UnreachableCodeElimination_h
michael@0: #define jit_UnreachableCodeElimination_h
michael@0: 
michael@0: #include "jit/MIRGraph.h"
michael@0: 
michael@0: namespace js {
michael@0: namespace jit {
michael@0: 
michael@0: class MIRGraph;
michael@0: 
michael@0: class UnreachableCodeElimination
michael@0: {
michael@0:     typedef Vector<MBasicBlock *, 16, SystemAllocPolicy> BlockList;
michael@0: 
michael@0:     MIRGenerator *mir_;
michael@0:     MIRGraph &graph_;
michael@0:     uint32_t marked_;
michael@0:     bool redundantPhis_;
michael@0:     bool rerunAliasAnalysis_;
michael@0:     bool disableAliasAnalysis_;
michael@0: 
michael@0:     bool prunePointlessBranchesAndMarkReachableBlocks();
michael@0:     void checkDependencyAndRemoveUsesFromUnmarkedBlocks(MDefinition *instr);
michael@0:     bool removeUnmarkedBlocksAndClearDominators();
michael@0:     bool removeUnmarkedBlocksAndCleanup();
michael@0: 
michael@0:     bool enqueue(MBasicBlock *block, BlockList &list);
michael@0:     MBasicBlock *optimizableSuccessor(MBasicBlock *block);
michael@0: 
michael@0:   public:
michael@0:     UnreachableCodeElimination(MIRGenerator *mir, MIRGraph &graph)
michael@0:       : mir_(mir),
michael@0:         graph_(graph),
michael@0:         marked_(0),
michael@0:         redundantPhis_(false),
michael@0:         rerunAliasAnalysis_(false),
michael@0:         disableAliasAnalysis_(false)
michael@0:     {}
michael@0: 
michael@0:     // Walks the graph and discovers what is reachable. Removes everything else.
michael@0:     bool analyze();
michael@0: 
michael@0:     // Removes any blocks that are not marked.  Assumes that these blocks are not
michael@0:     // reachable.  The parameter |marked| should be the number of blocks that
michael@0:     // are marked.
michael@0:     bool removeUnmarkedBlocks(size_t marked);
michael@0: 
michael@0:     // Call this function to prevent alias analysis to run a second time if we
michael@0:     // do not need it.
michael@0:     void disableAliasAnalysis() {
michael@0:         disableAliasAnalysis_ = true;
michael@0:     }
michael@0: };
michael@0: 
michael@0: } /* namespace jit */
michael@0: } /* namespace js */
michael@0: 
michael@0: #endif /* jit_UnreachableCodeElimination_h */