llvm-6502/include/llvm/Analysis/IntervalPartition.h
Chris Lattner 4dd88f6fbf Big changes. Interval*.h is now more or less finalized. IntervalPartition
is recoded to use IntervalIterators.  IntervalIterators can now maintain
their own memory or let an external entity do it.

Loop depth is a new user of IntervalPartition for calculating the loop
nesting depth of a basic block

TODO: add IntervalPartition capability to split intervals between the looping
portion and the "tail" portion.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69 91177308-0d34-0410-b5e6-96231b3b80d8
2001-06-25 03:54:14 +00:00

97 lines
3.4 KiB
C++

//===- IntervalPartition.h - Interval partition Calculation ------*- C++ -*--=//
//
// This file contains the declaration of the cfg::IntervalPartition class, which
// calculates and represents the interval partition of a method, or a
// preexisting interval partition.
//
// In this way, the interval partition may be used to reduce a flow graph down
// to its degenerate single node interval partition (unless it is irreducible).
//
// TODO: The IntervalPartition class should take a bool parameter that tells
// whether it should add the "tails" of an interval to an interval itself or if
// they should be represented as distinct intervals.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_INTERVAL_PARTITION_H
#define LLVM_INTERVAL_PARTITION_H
#include "llvm/Analysis/Interval.h"
#include <map>
class Method;
namespace cfg {
//===----------------------------------------------------------------------===//
//
// IntervalPartition - This class builds and holds an "interval partition" for
// a method. This partition divides the control flow graph into a set of
// maximal intervals, as defined with the properties above. Intuitively, a
// BasicBlock is a (possibly nonexistent) loop with a "tail" of non looping
// nodes following it.
//
class IntervalPartition {
typedef map<BasicBlock*, Interval*> IntervalMapTy;
IntervalMapTy IntervalMap;
typedef vector<Interval*> IntervalListTy;
IntervalListTy IntervalList;
Interval *RootInterval;
public:
typedef IntervalListTy::iterator iterator;
public:
// IntervalPartition ctor - Build the partition for the specified method
IntervalPartition(Method *M);
// IntervalPartition ctor - Build a reduced interval partition from an
// existing interval graph. This takes an additional boolean parameter to
// distinguish it from a copy constructor. Always pass in false for now.
//
IntervalPartition(IntervalPartition &I, bool);
// Destructor - Free memory
~IntervalPartition();
// getRootInterval() - Return the root interval that contains the starting
// block of the method.
inline Interval *getRootInterval() { return RootInterval; }
// isDegeneratePartition() - Returns true if the interval partition contains
// a single interval, and thus cannot be simplified anymore.
bool isDegeneratePartition() { return size() == 1; }
// TODO: isIrreducible - look for triangle graph.
// getBlockInterval - Return the interval that a basic block exists in.
inline Interval *getBlockInterval(BasicBlock *BB) {
IntervalMapTy::iterator I = IntervalMap.find(BB);
return I != IntervalMap.end() ? I->second : 0;
}
// Iterators to iterate over all of the intervals in the method
inline iterator begin() { return IntervalList.begin(); }
inline iterator end() { return IntervalList.end(); }
inline unsigned size() { return IntervalList.size(); }
private:
// addIntervalToPartition - Add an interval to the internal list of intervals,
// and then add mappings from all of the basic blocks in the interval to the
// interval itself (in the IntervalMap).
//
void addIntervalToPartition(Interval *I);
// updatePredecessors - Interval generation only sets the successor fields of
// the interval data structures. After interval generation is complete,
// run through all of the intervals and propogate successor info as
// predecessor info.
//
void updatePredecessors(Interval *Int);
};
} // End namespace cfg
#endif