113 lines
4.1 KiB
C++
113 lines
4.1 KiB
C++
//===- IntervalPartition.h - Interval partition Calculation -----*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the declaration of the IntervalPartition class, which
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// calculates and represents the interval partition of a function, or a
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// preexisting interval partition.
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//
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// In this way, the interval partition may be used to reduce a flow graph down
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// to its degenerate single node interval partition (unless it is irreducible).
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//
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// TODO: The IntervalPartition class should take a bool parameter that tells
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// whether it should add the "tails" of an interval to an interval itself or if
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// they should be represented as distinct intervals.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_INTERVAL_PARTITION_H
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#define LLVM_INTERVAL_PARTITION_H
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#include "llvm/Analysis/Interval.h"
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#include "llvm/Pass.h"
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#include <map>
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namespace llvm {
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//===----------------------------------------------------------------------===//
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//
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// IntervalPartition - This class builds and holds an "interval partition" for
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// a function. This partition divides the control flow graph into a set of
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// maximal intervals, as defined with the properties above. Intuitively, a
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// BasicBlock is a (possibly nonexistent) loop with a "tail" of non looping
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// nodes following it.
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//
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class IntervalPartition : public FunctionPass {
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typedef std::map<BasicBlock*, Interval*> IntervalMapTy;
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IntervalMapTy IntervalMap;
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typedef std::vector<Interval*> IntervalListTy;
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Interval *RootInterval;
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std::vector<Interval*> Intervals;
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public:
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static char ID; // Pass identification, replacement for typeid
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IntervalPartition() : FunctionPass(&ID), RootInterval(0) {}
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// run - Calculate the interval partition for this function
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virtual bool runOnFunction(Function &F);
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// IntervalPartition ctor - Build a reduced interval partition from an
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// existing interval graph. This takes an additional boolean parameter to
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// distinguish it from a copy constructor. Always pass in false for now.
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//
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IntervalPartition(IntervalPartition &I, bool);
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// print - Show contents in human readable format...
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virtual void print(std::ostream &O, const Module* = 0) const;
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void print(std::ostream *O, const Module* M = 0) const {
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if (O) print(*O, M);
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}
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// getRootInterval() - Return the root interval that contains the starting
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// block of the function.
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inline Interval *getRootInterval() { return RootInterval; }
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// isDegeneratePartition() - Returns true if the interval partition contains
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// a single interval, and thus cannot be simplified anymore.
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bool isDegeneratePartition() { return Intervals.size() == 1; }
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// TODO: isIrreducible - look for triangle graph.
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// getBlockInterval - Return the interval that a basic block exists in.
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inline Interval *getBlockInterval(BasicBlock *BB) {
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IntervalMapTy::iterator I = IntervalMap.find(BB);
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return I != IntervalMap.end() ? I->second : 0;
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}
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// getAnalysisUsage - Implement the Pass API
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virtual void getAnalysisUsage(AnalysisUsage &AU) const {
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AU.setPreservesAll();
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}
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// Interface to Intervals vector...
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const std::vector<Interval*> &getIntervals() const { return Intervals; }
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// releaseMemory - Reset state back to before function was analyzed
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void releaseMemory();
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private:
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// addIntervalToPartition - Add an interval to the internal list of intervals,
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// and then add mappings from all of the basic blocks in the interval to the
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// interval itself (in the IntervalMap).
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//
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void addIntervalToPartition(Interval *I);
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// updatePredecessors - Interval generation only sets the successor fields of
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// the interval data structures. After interval generation is complete,
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// run through all of the intervals and propagate successor info as
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// predecessor info.
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//
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void updatePredecessors(Interval *Int);
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};
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} // End llvm namespace
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#endif
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