1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/jit/UnreachableCodeElimination.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,64 @@
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_UnreachableCodeElimination_h
1.11 +#define jit_UnreachableCodeElimination_h
1.12 +
1.13 +#include "jit/MIRGraph.h"
1.14 +
1.15 +namespace js {
1.16 +namespace jit {
1.17 +
1.18 +class MIRGraph;
1.19 +
1.20 +class UnreachableCodeElimination
1.21 +{
1.22 + typedef Vector<MBasicBlock *, 16, SystemAllocPolicy> BlockList;
1.23 +
1.24 + MIRGenerator *mir_;
1.25 + MIRGraph &graph_;
1.26 + uint32_t marked_;
1.27 + bool redundantPhis_;
1.28 + bool rerunAliasAnalysis_;
1.29 + bool disableAliasAnalysis_;
1.30 +
1.31 + bool prunePointlessBranchesAndMarkReachableBlocks();
1.32 + void checkDependencyAndRemoveUsesFromUnmarkedBlocks(MDefinition *instr);
1.33 + bool removeUnmarkedBlocksAndClearDominators();
1.34 + bool removeUnmarkedBlocksAndCleanup();
1.35 +
1.36 + bool enqueue(MBasicBlock *block, BlockList &list);
1.37 + MBasicBlock *optimizableSuccessor(MBasicBlock *block);
1.38 +
1.39 + public:
1.40 + UnreachableCodeElimination(MIRGenerator *mir, MIRGraph &graph)
1.41 + : mir_(mir),
1.42 + graph_(graph),
1.43 + marked_(0),
1.44 + redundantPhis_(false),
1.45 + rerunAliasAnalysis_(false),
1.46 + disableAliasAnalysis_(false)
1.47 + {}
1.48 +
1.49 + // Walks the graph and discovers what is reachable. Removes everything else.
1.50 + bool analyze();
1.51 +
1.52 + // Removes any blocks that are not marked. Assumes that these blocks are not
1.53 + // reachable. The parameter |marked| should be the number of blocks that
1.54 + // are marked.
1.55 + bool removeUnmarkedBlocks(size_t marked);
1.56 +
1.57 + // Call this function to prevent alias analysis to run a second time if we
1.58 + // do not need it.
1.59 + void disableAliasAnalysis() {
1.60 + disableAliasAnalysis_ = true;
1.61 + }
1.62 +};
1.63 +
1.64 +} /* namespace jit */
1.65 +} /* namespace js */
1.66 +
1.67 +#endif /* jit_UnreachableCodeElimination_h */
